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Table des matières
Morphodynamic Study of the Channel of the North - Amazon River - Macapa,
Amapa, Brazil., Marcos Vinícius Barros [et al.] . . . . . . . . . . . . . . . . . . .
5
Morfodinâmica do Canal do Norte, Macapá, Rio Amazonas – Amapá., Marcos
Barros [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7
STUDY OF SOTALIA GUIANENSIS SOUNDS IN FRENCH GUIANA, Amandine Bordin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
Etude acoustique sur le Dauphin de Guyane (Sotalia guianensis), Amandine Bordin
9
Contribuições para uma Geografia Corográfica do Estuário do Rio Oiapoque: Uma
Evolução Histórica da Paisagem, Altino Caldeira [et al.] . . . . . . . . . . . . . .
11
Contributions to a Descriptive Geography of the Oiapoque River Estuary: A
Historical Evolution of Landscape, Pablo Cristiano Coelho [et al.] . . . . . . . . .
13
Human threats and climate change impacts on mangrove ecosystem, with specific
focus on French overseas territories, François Fromard . . . . . . . . . . . . . . .
15
Human threats and climate change impacts on mangrove ecosystem – Focus on
French overseas territories., François Fromard [et al.] . . . . . . . . . . . . . . . .
16
Cartographie de la dynamique côtière, Vulnérabilité à l’érosion du trait de côte et
Consultation via un service en ligne., Damien Galarraga [et al.] . . . . . . . . . .
17
Le nouveau Plan National d’Actions en Faveur des Tortues Marines en Guyane, Anaïs
Gainette [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Le nouveau Plan National d’Actions en Faveur des Tortues Marines en Guyane, Anaïs
Gainette [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Dynamique et rôle des vases fluides intertidales dans l’évolution morphodynamique
du littoral guyanais, Erwan Gensac . . . . . . . . . . . . . . . . . . . . . . . . . .
2
21
Classification Climatique de le Cours Inférieur de la Rivière Oiapoque Selon Méthodologie K´’oppen, Themístocles Gomes Sobrinho [et al.] . . . . . . . . . . . . . . . . . 23
The climatic classification of the lower course of the Oiapoque river’s basin according to the K´’oppen methodology, Themístocles Gomes Sobrinho [et al.] . . .
25
Dynamique et rôle des vases fluides intertidales dans l’évolution morphodynamique
du littoral guyanais, Evelyne Goubert [et al.] . . . . . . . . . . . . . . . . . . . .
27
Evolution Holocene of Belt Southern Lake, Coastal Plain of Amapa, Amazon
Coast, Brazil., Kerly Jardim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29
Evolução holocênica do cinturão lacustre meridional, planície costeira do Amapá,
Costa amazônica, Brasil., Kerly Jardim [et al.] . . . . . . . . . . . . . . . . . . . .
30
Microfossils and environmental changes, Maracá Islands, Amazon coast, Amapá., Lazaro
Laut [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Mise en place d’un indicateur poisson DCE compatible pour les estuaires de
Guyane française, Mario Lepage . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34
Mise en place d’un indicateur poisson DCE compatible pour les estuaires de
Guyane française, Mario Lepage [et al.] . . . . . . . . . . . . . . . . . . . . . . . .
35
Groundwater processes on the French Guiana coastal plain. A historical and
prospective ecohydrological brainstorm., Lambs Luc [et al.] . . . . . . . . . . . .
36
Groundwater processes on the French Guiana coastal plain. A historical and
prospective ecohydrological brainstorm., Lambs Luc . . . . . . . . . . . . . . . .
37
Geo Coastland, Barbara Martel . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
Geo Coastland au service de la gestion intégrée et durable des zones côtières, Barbara Martel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
Tracking the origin and dynamics of the sandy beaches in the context of global
change and ecosystem services: a French Guiana project to be expanded to the
Brazilian window, Philippe Negrel [et al.] . . . . . . . . . . . . . . . . . . . . . .
40
French Guiana stranding network implementation, Claire Pusineri [et al.] . . . . .
42
Présentation du Réseau de suivi des Echouages de Guyane, Claire Pusineri [et al.]
44
Stability of the muddy banks from Ponta of Marrecal (Brazil) to Comté river
(French Guiana), Amazon coast, Laysa Santana [et al.] . . . . . . . . . . . . . . .
46
3
sdfwa, Laysa Santana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
Stability of the mud banks from Ponta of Marrecal (Brazil) to Comté river (French
Guiana), Amazon coast, Laysa Santana [et al.] . . . . . . . . . . . . . . . . . . .
49
Estabilidade dos bancos lamosos desde a Ponta do Marrecal (Brasil) ao rio Comté
(Guiana Francesa), costa Amazônica, Laysa Santana [et al.] . . . . . . . . . . . .
51
Influence of Geomorphology Pattern on Mangrove Establishment. A case study
from the North Cape at the Amazon river mouth, Amapá, Brazil, Valdenira Santos [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
Influence of Geomorphology Patterns on Mangrove Establishment: A case study
from the mouth of the Amazon River, Cape North, Brazil, Valdenira Santos [et al.] 54
A search-matching model of fisheries, Nicolas Sanz [et al.] . . . . . . . . . . . . .
56
Carbon stock and sequestration in the Brazilian mangroves, Mario Soares [et al.]
57
Mangrove mapping using remote sensed data crossed into GIS statistical analysis, Florent Taureau [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
59
Mapping mangrove using remote sensing data combined into statistical GIS analysis, Florent Taureau [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
61
Spatio-temporal variability of benthic biogeochemical fluxes at the sediment-air
and sediment-water interfaces in the Sinnamary mangrove (French Guiana), Gérard
Thouzeau [et al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
62
Estimating pCO2 from remote sensing in the Amazon river plume, Aline Valerio [et
al.] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
64
Estimating pCO2 from remote sensing in the Amazon river plume, Aline Valerio
66
Morphodynamic survey of an embayed rotating beach during the approach of a
mud bank: Montjoly, French Guiana, Guillaume Brunier [et al.] . . . . . . . . . .
67
Morphodynamic survey of a rotating embayed beach during the approach of a
mud bank: Montjoly, French Guiana, Guillaume Brunier [et al.] . . . . . . . . . .
69
Rapid shoreline erosion induced by human engineering on the Mana polder, western French Guiana., Guillaume Brunier [et al.] . . . . . . . . . . . . . . . . . . . .
71
Liste des auteurs
72
4
Morphodynamic Study of the Channel of the
North - Amazon River - Macapa, Amapa,
Brazil.
Marcos Vinícius Barros
∗†
, Alberto Figueiredo Jr
, Valdenira Santos
∗
∗
1
1
Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá, Núcleo de Pesquisas Aquáticas
- IEPA/NuPAq (IEPA) – Rod. JK, km 10, 68902-280, Fazendinha, Macapá, Amapá, Brésil
The Amazon River is one of the most dynamic places in the world because of its high flow
and sediment load, in special, at its lower course. This research deals with the morphology
caused by sedimentation processes that occur recently in the Channel of the Amazon River, in
front the City of Macapa, Amapa State, Brazil. The morphodynamic characterization was done
through the interpretation of two-dimensional images of seismic profiles collected in: May 2014
by a sub-bottom profiler Bathy 2010 SyQwest with frequency transducer modulated at 1 to 3.5
kHz coupled to a DGPS Trimble; and June 2014 with a profiler X-Star SB 512i Edgetech in
frequency modulation of 7 to 12 kHz. The profiles were collected perpendicular (five lines) and
parallel (two lines) to the left bank. The records were processed and interpreted highlighting the
morphological bed structures. The predominance of four types of morphology was observed in
the area: the sandwaves fields (SWF), the underwater dunes (UWD), the major fluvial channel
(MFC) and the channel spurs (CSP). These features are arranged respectively in that order if one
starts to characterize the middle fluvial channel to the left bank of the Amazon River. The subbottom structures feature orientation to the northeast, following the direction of the prevailing
regional ebb tide, according to results of SILVA (2008). Except for the SWF, which showed
orientation for southwest corroborating to the previously findings described by VITAL (1996).
DALMASCHIO & BASTOS (2007) point out that the sandwaves commonly present reversion of
asymmetry in areas of influence of macro tides. For TORRES & ARCHER (2003) the alternation
in the direction of migration of bed forms is associated with strong interaction between the fluvial
and coastal processes by the effect of the flood tide. The UWD were observed near the main
channel. STRASSER (2008) advocates that this behavior is related mainly to the high flow
rate values (Froude number) active near the bottom. Apparently, the UWD are the forms with
the highest incidence in this area of the Channel. EINSTEIN (1950) states that the UWD
are the most frequent and relevant bed forms observed in alluvial flow in these environments,
originated from the flow resistance or caused by the influence on sediment transport. The MFC
was identified as a reflector following the bottom topography, in the case of the basement of
∗
†
Intervenant
Auteur correspondant: [email protected]
5
paleochannel. CHRISTOFOLETTI (1981) reiterates that the bed changes in MFC in fluvial
environments are constant due to the flow dynamics and sediment transport processes. The
sequence of inclined and superimposed reflectors on the channel margin shows the presence of
CSP. According READING (1996) this feature is typical in regions influenced by tide, being
composed of relatively fine sediment accretion with lateral flanks and heterolytic stratification.
The morphology observed on the banks and bed in Channel of the North of Amazon River
indicates dynamism of sedimentary processes with sediment transport dominated by the ebb
tidal currents. The described forms show an important bedload transport towards the mouth of
the Amazon River and this process should be further investigated because they generate social,
economic
and geographical
consequences
Mots-Clés:
bedforms, sediment,
seismicfor the region.
6
Morfodinâmica do Canal do Norte, Macapá,
Rio Amazonas – Amapá.
Marcos Barros
1
∗†
, Alberto Figueiredo , Valdenira Santos‡
1
O rio Amazonas em função de sua alta vazão e carga sedimentar transforma seu baixo curso
e constitui um dos lugares mais dinâmicos do mundo. Esta pesquisa observou a morfologia originada pelos processos de sedimentação que ocorrem recentemente na área do Canal do Norte
– Rio Amazonas/AP, em frente à cidade de Macapá. A caracterização morfodinâmica foi feita
através da interpretação de imagens bidimensionais de perfis sísmicos coletados em maio de 2014
por um perfilador de sub fundo Bathy-2010 SyQwest com transdutor modulado na frequência
R
de 1 – 3,5 kHz acoplado a um DGPS Trimble.
Os perfis foram coletados perpendiculares a
margem esquerda do rio (cinco) e transversais (dois). Os registros foram processados e interpretados destacando as estruturas morfológicas de fundo. Foi constatada a predominância de três
tipos de morfologia na área: os campos de sandwaves, as dunas subaquáticas e o canal principal. As estruturas de sub-fundo citadas apresentam orientação de migração predominante para
nordeste, obedecendo a direção da maré vazante que predomina na região segundo resultados de
estudos científicos. Os campos de sandwaves apresentam refletores contínuos, retilíneos e refletores ondulados em áreas mais afastadas. A disposição desses refletores demonstra o constante
retrabalhamento sedimentar típico de regiões mais rasas e a presença de refletores ondulados a
noroeste desses campos, apontam a migração dessas estruturas. As dunas subaquáticas foram
observadas próximas ao canal principal e sua presença indicam maiores velocidades de corrente
para a manutenção e formação dessas estruturas. Nas dunas, a capacidade de penetração do sinal
sísmico foi limitada possivelmente pelo grau de compactação e/ou tipo de sedimento (arenoso).
No canal principal foi identificado um refletor seguindo a topografia de fundo tratando-se do embasamento e paleocalha do canal. Uma espessa camada de sedimentos preenchendo a paleocalha
caracteriza altos valores de velocidade de corrente e transporte de sedimentar. Verificou-se uma
sequencia de refletores inclinados e sobrepostos na margem do canal evidenciam a presença de
migração de barras formando atualmente terraços de maré erodidos na margem do canal principal. Neste sentido, devemos assumir que os aspectos morfológicos observados nas margens e
leito do Canal do Norte indicam um dinamismo dos processos sedimentares com transporte de
sedimentos dominado pelas correntes de maré vazante. Esse dinamismo só é possível com presença de material arenoso no canal, como atestado em trabalhos anteriores. As formas descritas
mostram um importante transporte de carga de fundo em direção a foz do Rio Amazonas e tal
processo deve ser melhor investigado, pois geram consequências sociais, econômicas e geográficas
paraMots-Clés:
a região. Formas de fundo, sedimentos, sísmica.
∗
Intervenant
‡
†
7
STUDY OF SOTALIA GUIANENSIS
SOUNDS IN FRENCH GUIANA
Amandine Bordin
1
∗ 1
Groupe d’Etude et de Protection des Oiseaux en Guyane/Réserve Naturelle Nationale de l’Ile du
Grand-Connétable (GEPOG/RNNC) – 15 avenue Pasteur, Guyane française
In French Guiana, the Guiana Dolphin (Sotalia guianensis) is observed along the coastline,
estuaries and occasionally on the Continental Shelf up to 40 kilometers offshore (Van Canneyt
et al., 2009 ; Brichet, 2011 ; Bordin et al., 2012).
Several observations were documented around the Remire islands and the Connetable islands
area, as well as proven occurrences in the river mouths of Cayenne, Mahury, the Approuague,
the Oyapock, Mana and Maroni (Bouillet et al., 2002). Functionally, the areas close to the
Mahury river and surrounding Cayenne could be a feeding area, with some degrees of fidelity.
The dolphins could also be present in the estuary for functional activities such as rest (Bordin/GEPOG, pers. comm., 2015). Since 2014, the Marine Reserve of the Grand-Connetable
Island established a photo-identification catalog to study the Guiana Dolphin population.
Acoustic method is a complementary approach to detect cetacean presence. The Guiana Dolphin produces different varieties of sounds, especially echolocation clicks to navigate, forage and
communicate in turbid waters. We present here the first acoustic recordings analysis of Sotalia
Guianensis in French Guiana, including odontocete-type sounds as clicks and whistles, and new
type of sounds which can be classified as pulsed sounds (bursts) or incremental signals. Future
research will be necessary to better define the nature/profile of these sound structures and the
potential links between these emitted sounds and specific behaviors (feeding, location, etc.).
Mots-Clés: Guiana Dolphin, French Guiana, acoustic, sound shapes
∗
Intervenant
8
Etude acoustique sur le Dauphin de Guyane
(Sotalia guianensis)
Amandine Bordin
1
∗ 1
Groupe d’Etude et de Protection des Oiseaux en Guyane/Réserve Naturelle Nationale de l’Ile du
Grand-Connétable (GEPOG/RNNC) – 15 avenue Pasteur, Guyane française
Le Dauphin de Guyane ou Sotalie (Sotalia guianensis) est l’un des plus petits représentants
des Cétacés. Son aire de répartition est relativement restreinte puisqu’il n’est rencontré que dans
l’Ouest de l’Océan Atlantique, du Brésil (Etat de Santa Catarina) jusqu’au Honduras en passant
par la Guyane française et le Suriname. Ce dauphin fréquente essentiellement les eaux calmes
et peu profondes des milieux estuariens et côtiers, incluant les habitats rocheux où il s’alimente
de poissons et crustacés. Il n’est pas rare de l’apercevoir dans les estuaires des grands fleuves
amazoniens qu’il peut remonter sur quelques kilomètres. Au large de la Guyane, il n’évolue guère
au-delà des 40 premiers kilomètres du plateau continental.
Le Dauphin de Guyane est une espèce discrète, farouche et évoluant dans un environnement
peu accessible. Le recours aux méthodes de détection acoustique en complément des méthodes d’observations visuelles est donc particulièrement intéressant. Le suivi acoustique est une
technique complémentaire fréquemment utilisée sur les mammifères marins pour détecter leur
présence, identifier leurs activités et évaluer leurs variabilités saisonnières. Tous les cétacés produisent des sons relativement stéréotypés permettant de les identifier dans un bruit ambiant
marin. Les sons produits sont très variés et peuvent être de type impulsif tel que les clics, pour
se repérer et s’orienter, ou de type continu comme les sifflements, plus aigus et généralement
utilisés pour communiquer et se reconnaître.
Le Dauphin de Guyane possède un répertoire vocal essentiellement composés de claquements
et de sifflements qu’il utilise au cours de diverses activités et interactions sociales (déplacement,
reproduction, chasse...). Les études menées sur le sujet au Brésil ont montré que les émissions
pouvaient varier en fonction des populations et des secteurs (durée des sifflements et gamme
de fréquences variables entre les différents groupes d’animaux étudiés). Afin de compléter ces
efforts et de mieux comprendre cette espèce, la Réserve Naturelle Nationale de l’Ile du GrandConnétable entreprend une étude sur le Dauphin de Guyane en recourant au méthode acoustique.
Ce projet, réalisé en collaboration avec des experts et acousticiens, concerne le secteur du Connétable, les différents habitats rocheux du littoral cayennais, la rivière de Cayenne et le fleuve
Mahury. A ce jour, plusieurs acquisitions (claquements et sifflements) ont été réalisées dans deux
sites à l’aide d’un hydrophone omnidirectionnel. Les données acoustiques sont en cours d’analyse
et permettront d’obtenir les premiers spectrogrammes et abaques pour l’espèce en Guyane. Ces
résultats permettront ensuite d’envisager le déploiement d’hydrophones fixes qui enregistrerontt
en permanence et de manière autonome le milieu marin guyanais.
Ces travaux s’inscrivent dans une dynamique régionale de meilleure compréhension de cette
∗
Intervenant
9
espèce emblématique et menacée par le développement des activités humaines (pêche au filet,
pollution,
chantiers
portuaires)
et Grand
des modifications
de son milieu.
Mots-Clés:
Réserve
de l’Ile du
Connétable, Dauphin
de Guyane, acoustique, hydrophones
10
Contribuições para uma Geografia Corográfica
do Estuário do Rio Oiapoque: Uma Evolução
Histórica da Paisagem
Altino Caldeira∗ 1 , Pablo Cristiano Coelho
Sobrinho †
1
† 1
, Themístocles Gomes
, Laysa Santana 2 , Valdenira Santos
2
1
Pontifícia Universidade Católica de Minas Gerais - PUCMinas (Programa de Pós-Graduação em
Geografia - Tratamento da Informação Espacial / PPGG-TIE) – Av. Itaú, 505 - Prédio Emaús - Dom
Cabral - Belo Horizonte/MG - CEP: 30535012 - Telefone geral: (31) 3413.6370, Brésil
2
Os estudos sobre as paisagens do estuário do Rio Oiapoque foram escritos por diversos
pesquisadores desde a primeira expedição do navegador espanhol Vicente Pinzon. Desde o
primeiro reconhecimento da área, feito em 1500 por Vicente Pinzon, companheiro de navegação
de Cristóvão Colombo, o cartógrafo Diego Ribero afirmou não ter encontrado nada de interessante (ou vantagem econômica) no prolongamento do litoral do Novo Mundo situado desde
a foz do Rio Essequibo ao Cabo de São Roque, costa esta chamada pelos holandeses, naquela
época, como ”Costa Selvagem”. Este artigo buscou refazer uma breve análise e uma descrição da
representação geográfica das paisagens da região fronteiriça entre a Guiana Francesa e o Brasil,
por meio de pesquisa de documentos, da cartografia e da literatura histórica sobre o tema. Na
forma de esquema foi feito, do ponto geográfico e histórico, uma descrição das expedições organizadas na região do estuário. No decorrer da pesquisa foi possível perceber um consenso de
que as medidas cartográficas, de localização e distância foram descritas com erros significativos
ao longo dos séculos, em particular pela falta de padronização. Esses erros corroboraram com a
imprecisão da linha de costa entre o Amapá e a Guiana Francesa, cunhados em mapas e cartas,
ora potencializando dimensões e distancias entre localidades, ora as reduzindo. Sobre a Guiana
Francesa, departamento ultramarino da França localizado a margem esquerda do Rio Oiapoque,
o geógrafo Paul Vidal de La Blache afirma que o nome Guiana é mencionado pela primeira vez
no mapa de 1599 após a expedição britânica dirigida por Walter Raleigh, essa região tinha mais
ligação com o Caribe do que com o resto do continente. Sobre o ponto de vista cartográfico e
histórico, o artigo 8 do Tratado de Utrecht diz: Sua Majestade, muito cristã, remove ”todos os
direitos ou reivindicações que podem ou querem sobre a propriedade da terra chamada Cabo
Norte, situada entre o Rio Amazonas e o Rio Oiapoque ou Vicente Pinzon”, inferindo, desde
1713, que o Rio Oiapoque apresentava-se como o limite fronteiriço entre a antiga Colônia portuguesa (Brasil) e a antiga colônia francesa (Guiana Francesa). Por ser um estuário equinoxial,
fortemente influenciável pela altura da maré, a área costeira de estudo é muito dinâmica, dada a
∗
†
Intervenant
11
quantidade de sedimentos transportados pelos rios Amazonas, Araguari e Oiapoque. Os mapas e
os relatórios de viagens pesquisados relacionados à foz do Rio Oiapoque tem diferenças específicas no percurso histórico. Tais desacordos podem estar relacionados às imprecisões cartográficas
e/ou remodelagens naturais da paisagem. Alguns exemplos foram percebidos durante a pesquisa,
o mapa da Marinha da França de 1780 apresenta contornos do Cabo Orange divergente dos atuais
apresentados pelo mapa da Marinha do Brasil de 2000. Tais divergências estão relacionados a
forma e dimensão. Outros exemplos podem ser percebidos ao longo da linha costeira entre o Rio
Amazonas e o próprio Rio Oiapoque. O mais significativo dos exemplos refere-se a inexistência
atual da bifurcação da foz do Rio Araguari, antes cartografada em mapas dos século XVIII. O
objetivo deste estudo foi verificar e comparar, nos relatos de viagem e expedições, o quanto as
paisagens
sofreram
mudanças nos últimos
três séculos.
Mots-Clés:
Rio de
Oiapoque/Vicente
Pinzon, Estuário,
Paisagem, Fronteira Brasil, Guiana Francesa.
12
Contributions to a Descriptive Geography of
the Oiapoque River Estuary: A Historical
Evolution of Landscape
Pablo Cristiano Coelho ∗ 1 , Altino Caldeira ∗ † , Themistocles Raphael
Gomes Sobrinhho ∗ ‡ , Laysa Santana ∗ § , Valdenira Santos ∗ ¶
1
Studies on the landscapes of the estuary of the Oiapoque river were written by several researchers since the first expedition of the Spanish navigator Vicente Pinzon. Since the first
recognition of the area, made in 1500 by Vicente Pinzon, navigation companion of Christopher Columbus, the cartographer Diego Ribeiro said he had not found anything interesting (or
economic advantage) in the extension of the New World coast located from the estuary of the
Essequibo river to Cape San Roque, coast call by the Dutch at that time as ”Wild Coast”. This
article aimed remake a brief analysis and a description of the geographical representation of the
landscape of the border region between French Guiana and Brazil, through document research,
cartography and historical literature on the subject. About the French Guiana, overseas department of France located to the left bank of the r Oiapoque river , the geographer Paul Vidal de
la Blache says the Guyana name is first mentioned on the map 1599 after the British expedition led by Walter Raleigh, this region had more connection to the Caribbean than with the
rest of the continent. About cartographic and historical point of view, Article 8 of the Treaty
of Utrecht says: Her Majesty, very Christian, remove ”all rights or claims that may or may
want on the ownership of land called North Cape, situated between the Amazon river and the
Oiapoque river or Vicente Pinzon”, inferring, since 1713, the Oiapoque river showed itself as the
border line between the former Portuguese colony (Brazil) and the former French colony (French
Guiana). This article aimed remake a brief analysis and a description of the geographical representation of the landscape of the border region between French Guiana and Brazil, through
document research, cartography and historical literature on the subject. In the scheme was
made, geographically and historically, a description of the expeditions organized in the estuary
region. During the research it was revealed a consensus that the cartographic measures, location
and distance were described with significant errors over the centuries, in particular the lack of
standardization. These errors have corroborated with the inaccuracy of the coastline between
Amapá and French Guiana, minted in maps and charts, sometimes increasing dimensions and
distances between sites, sometimes reducing. The objective of this study was to evaluate and
compare, in travel writings and expeditions, how the landscapes have undergone changes in the
∗
Intervenant
Auteur correspondant:
‡
§
¶
†
[email protected]
[email protected]
[email protected]
[email protected]
13
last three centuries. By being a equinoxial estuary, strongly influenced by the height of the
tide, the coastal area of study is very dynamic, given the amount of sediments transported by
Amazon, Araguari and Oiapoque. Some examples were perceived during the search, the map of
the French Navy from 1780 shows the Cabo Orange profile divergent the shown on the current
map of the Brazil’s Navy. Such differences are related to size and shape. Other examples can be
seen along the shoreline between the Amazon river and the Oiapoque river. The most significant
examples refers to Current bifurcation lack the mouth of the Araguari river, before charted on
maps of the eighteenth century. The maps and researched travel reports related to the Oiapoque
river estuary has specific differences in the historical route. Such disagreements may be related
to cartographic
and/ Vicente
/ or natural
landscape
Mots-Clés: inaccuracies
River Oiapoque
Pinzon,
Estuary, remodelings.
Landscape, the Brazil, French Guiana.
14
Human threats and climate change impacts on
mangrove ecosystem, with specific focus on
French overseas territories
François Fromard
∗ 1,2,3
1
Laboratoire Ecologie Fonctionnelle et Environnement (EcoLab) – CNRS : UMR5245, Observatoire
Midi-Pyrénées, PRES Université de Toulouse, Université Paul Sabatier (UPS) - Toulouse III, Institut
National Polytechnique de Toulouse - INPT – 118 Route de Narbonne 31062 Toulouse, France
2
CNRS - Université Paul Sabatier – CNRS : UMR5245 – Université Paul Sabatier - Bât. 4R1 - 118,
route de Narbonne 31062 Toulouse cedex 9, France
3
Groupement de Recherche CNRS 3586 Littoral de Guyane sous Influence Amazonienne (GDR LiGA)
– CNRS - Guyane, Cayenne, Guyane française
Mangrove forest is a major ecosystem of tropical coasts that supports a wide range of ecosystem services, including protection against coastal erosion, a significant carbon storage capacity,
nursery site for marine species, and retention of terrigenous pollutants. However, mangroves have
been largely threatened by direct human activities especially with the development of shrimp
farming, urban expansion and agricultural practices over the last decades. Globally, around 40%
of mangrove forests have been lost since the mid-twentieth century. Mangroves are also particularly sensitive to climate change, with various impacts on ecosystem structuring, functioning
and dynamics. Sea level rise, increase in air and water temperatures, changes in tropical storm
frequency and intensity are the factors that are the most likely to affect their integrity. Where
they have not been directly disturbed by man, mangroves can be regarded as sentinels of climate
change. This is true for the mangroves of French tropical overseas territories, that are specifically
monitored
in the mangrove,
frameworkClimate
of the CNRS/IRD’s
2015 services,
Year of the
Mangrove
Mots-Clés:
change, Ecosystem
French
overseasinitiative.
territories, French
Guiana
∗
Intervenant
15
Human threats and climate change impacts on
mangrove ecosystem – Focus on French
overseas territories.
François Fromard
∗† 1,2
, Antoine Gardel , Christophe Proisy , Edward
Anthony , Romain Walcker
1
2
CNRS - Université Paul Sabatier – CNRS : UMR5245 – Université Paul Sabatier - Bât. 4R1 - 118,
route de Narbonne 31062 Toulouse cedex 9, France
Mangroves are a major, emblematic ecosystem of tropical coasts that provide a wide range
of ecosystem services, including protection against coastal erosion, a significant carbon storage
capacity, nursery sites for fish and crustacean species, and retention of terrigenous pollutants.
Mangroves have been significantly decimated over the last few decades by direct human activities
with the development of shrimp farming, urban expansion and agricultural practices.
Mangroves, and other coastal wetlands, are also particularly sensitive to climate change, with
different impacts on ecosystem structuring, functioning and dynamics. Sea level rise could promote landward mangrove migration at the expense of adjacent ecosystems less effective in carbon
storage capacity, while high levels of atmospheric CO2 could enhance mangrove tree growth. A
lower frequency of extreme low temperatures should facilitate a poleward expansion of mangroves,
whereas extreme events such as cyclones and tsunamis should lead to mangrove retreat or demise.
These processes are recognized variably worldwide. In particular, climate change impacts associated with direct, growing anthropogenic disturbances should drastically alter mangrove ecosystem services. Specific impacts and adaptive strategies of mangroves in the face of regional and
global climate change will be addressed in the proposed poster.
A specific focus will be made on French overseas territories, where mangroves extend over 100,000
ha, with around 70% for French Guiana.
French overseas territory mangroves are specifically monitored in the framework of the CNRS/IRD’s
2015Mots-Clés:
Year of the Mangrove,
Mangrove Climate
initiativechange, Ecosystem services, French overseas territories, French
Guiana
∗
†
Intervenant
16
Cartographie de la dynamique côtière,
Vulnérabilité à l’érosion du trait de côte et
Consultation via un service en ligne.
Damien Galarraga
1
∗ 1
, Jérôme Le Fol
∗
, Christophe Proisy 2 , Konrad Rolland
1
2
Guyane SIG - Région Guyane – Guyane française
IRD - UMR AMAP – Institut de recherche pour le développement [IRD] : UMR0931 – France
Interface de tous les enjeux, le littoral guyanais concentre l’essentiel des infrastructures, des
activités socio-économiques, une croissance exponentielle de l’occupation humaine face à une des
plus fortes dynamiques côtières au monde. L’aménagement et la protection du littoral guyanais
sont donc deux enjeux à mener de front pour lesquels la Région Guyane s’est investie à travers sa
participation à différents projets de recherche et de développement comme les projets PROCLAM
(financement INTERREG, 2006-2008) et ECOCOT (financement FEDER, 2013-2015).
Dans ces projets, l’usage de la télédétection pour la connaissance et la compréhension de la dynamique littorale est valorisé sur la base de travaux scientifiques menés depuis plus de vingt ans.
Dans ce contexte, la Région Guyane a signé une convention de transfert des méthodes de production d’indicateurs avec l’ensemble des partenaires du projet INFOLITTORAL (financement
Fond Unique Interministériel, 2010-2012). Cette mission a été confiée à la Plateforme Régionale
GUYANE SIG afin de poursuivre la mise à jour des trois indicateurs suivants :
- Suivi du trait de côte ;
- Suivi des bancs de vase exondés ;
- Indice de vulnérabilité à l’érosion.
Au sein de notre équipe, nous disposons d’une expérience d’une dizaine d’année permettant
d’appréhender les différents aspects du suivi de la dynamique côtière guyanaise :
- techniques d’Observation de la Terre : maitrise des contraintes locales d’acquisition, extraction
d’informations issue d’images de télédétection, traitement de données d’information géographique
;
- informatique : structuration et exploitation de bases de données, diffusion web ;
- scientifique : géographie humaine et physique.
∗
Intervenant
17
Notre objectif est de produire une information régulière et fiable concernant le littoral guyanais
avec les moyens technologiques et les sources d’informations disponibles, tout en s’appuyant sur
les résultats existants et les progrès scientifiques pour que les acteurs publics du territoire disposent d’un état des lieux et d’une connaissance actualisée permettant une prise de décision
pertinente et éclairée.
Le transfert des résultats du projet INFOLITTORAL, dans le contexte actuel (mise à disposition d’images SPOT 6/7 dans le cadre de l’Appel à Projet SEAS II) et grâce à la disponibilité
de données d’archive existantes, ont permis de constituer une première base de données multidate vectorielles et images et une mise à jour des trois indicateurs retenus sur l’ensemble du
littoral pour l’année 2014, en s’appuyant sur l’encadrement scientifique de l’IRD, UMR AMAP.
Nous présenterons
- les méthodes de production employées ;
- les améliorations et évolutions qui peuvent être apportées ;
- le l’articulation de ces résultats avec les autres initiatives locales ;
- la collaboration opérationnelle avec les spécialistes présents localement.
Nous discuterons également du potentiel de la base de données ainsi constituée et intégrée dans
le serveur de Guyane SIG pour une exploitation à différents niveaux :
- Applications thématiques dédiées de consultations des données ;
- Catalogage de ces données permettant la consultation, la visualisation, leur interrogation et
leurMots-Clés:
téléchargement
(navigateur
internet,
flux
de Indice
diffusion
WMS/WFSà sur
logiciel).
Télédétection,
Banc
de vase,FTPs,
Trait de
côte,
de vulnérabilité
l’érosion,
Diffusion
d’information.
18
Le nouveau Plan National d’Actions en Faveur
des Tortues Marines en Guyane
Anaïs Gainette
1
∗ 1
, Rachel Berzins
, Hélène Delvaux
∗
∗
2
1
2
ONCFS – Guyane française
DEAL – Guyane française
Suite au bilan et à l’évaluation du Plan de Restauration des Tortues Marines en Guyane (20072012), l’Etat, appuyé par l’ensemble des partenaires du Réseau Tortues Marines de Guyane, a
décidé de poursuivre les efforts et de conforter les acquis obtenus par la mise en place d’un
Plan National d’Actions en faveur des Tortues Marines (PNATM). Celui-ci, d’une durée de
10 ans afin de corréler la durée du plan à la biologie de l’espèce et à la nature des résultats
attendus, a été lancé en 2013. Le processus de validation, local et national, s’est terminé en mai
2015 avec la conclusion favorable du Ministère de l’Ecologie, du Développement Durable et de
l’Energie (MEDDE), recueillie à l’issu d’une enquête publique. Ce PNATM est un document de
planification stratégique pour améliorer l’état de conservation des 3 principales espèces de tortues
marines présentes en Guyane : la tortue luth (Dermochelys coriacea), la tortue verte (Chelonia
mydas) et la tortue olivâtre (Lepidochelys olivacea). Ces trois espèces sont toutes inscrites
sur la liste rouge de l’UICN comme espèces menacées. 5 objectifs spécifiques classés par degré
décroissant d’importance et 2 objectifs spécifiques transversaux ont été déterminés collectivement
: 1/ Réduction des menaces, 2/ Amélioration des connaissances au service de la conservation, 3/
Coopération transfrontalière, 4/ Education à l’environnement, 5/Valorisation socio-économique,
6/ Révision du mode de gouvernance, et 7/ Mise en réseau des acteurs. Ce nouveau plan a été
élaboré à travers une démarche de concertation et d’implication de l’ensemble des partenaires
liés à la conservation des tortues marines en Guyane. Un grand nombre de réunions ont été
programmées afin d’aboutir à un document intégrant les différentes sensibilités. La gouvernance
et le suivi du plan ont été mis en place dès le début de l’année 2015 avec la première réunion du
Comité de pilotage, qui s’est suivie de la première séance de la Cellule de coordination du plan
et de groupes de travail thématiques. Une demande de subvention sera déposée prochainement
au programme opérationnel régional FEDER-FSE 2014-2020 pour assurer le financement d’une
grande
partie desTortues
actions
du planConservation
dans les deux prochaines années.
Mots-Clés:
Marines,
∗
Intervenant
19
Le nouveau Plan National d’Actions en Faveur
des Tortues Marines en Guyane
Anaïs Gainette
∗ 1
1
, Rachel Berzins† , Hélène Delvaux‡
ONCFS – Guyane française
Suite au bilan et a l’evaluation du Plan de Restauration des Tortues Marines en Guyane
(2007-2012), l’Etat, appuye par l’ensemble des partenaires du Reseau Tortues Marines de
Guyane, a decide de poursuivre les eorts et de conforter les acquis obtenus par la mise en
place d’un Plan National d’Actions en faveur des Tortues Marines (PNATM). Celui-ci, d’une
duree de 10 ans an de correler la duree du plan a la biologie de l’espece et a la nature des
resultats attendus, a ete lance en 2013. Le processus de validation, local et national, s’est termine en mai 2015 avec la conclusion favorable du Ministere de l’Ecologie, du Developpement
Durable et de l’Energie (MEDDE), recueillie a l’issu d’une enqu^ete publique. Ce PNATM est
un document de planication strategique pour ameliorer l’etat de conservation des 3 principales especes de tortues marines presentes en Guyane : la tortue luth (Dermochelys coriacea), la tortue verte (Chelonia mydas) et la tortue oliv^atre (Lepidochelys olivacea). Ces trois
especes sont toutes inscrites sur la liste rouge de l’UICN comme especes menacees. 5 objectifs
speciques classes par degre decroissant d’importance et 2 objectifs speciques transversaux
ont ete determines collectivement : 1/ Reduction des menaces, 2/ Amelioration des connaissances au service de la conservation, 3/ Cooperation transfrontaliere, 4/ Education a
l’environnement, 5/Valorisation socio-economique, 6/ Revision du mode de gouvernance, et
7/ Mise en reseau des acteurs. Ce nouveau plan a ete elabore a travers une demarche de
concertation et d’implication de l’ensemble des partenaires lies a la conservation des tortues
marines en Guyane. Un grand nombre de reunions ont ete programmees an d’aboutir a
un document integrant les dierentes sensibilites. La gouvernance et le suivi du plan ont
ete mis en place des le debut de l’annee 2015 avec la premiere reunion du Comite de pilotage, qui s’est suivie de la premiere seance de la Cellule de coordination du plan et de
groupes de travail thematiques. Une demande de subvention sera deposee prochainement au
programme operationnel regional FEDER-FSE 2014-2020 pour assurer le nancement d’une
grande
partie desTortues
actions
du planConservation
dans les deux prochaines annees.
Mots-Clés:
Marines,
∗
Intervenant
‡
†
20
Dynamique et rôle des vases fluides intertidales
dans l’évolution morphodynamique du littoral
guyanais
Erwan Gensac
1
∗ 1
Géosciences Marines et Géomorphologie du Littoral (GMGL) – UMR CNRS 6538 LDO-GMGL –
France
La dynamique des vases intertidales jouent un rôle important dans le fonctionnement des
littoraux en favorisant soit l’accrétion, la stabilisation ou l’érosion des zones intertidales aussi
bien dans les systèmes tempérés que dans les systèmes. Le littoral de Guyane fait partie de
la plus longue côte vaseuse au monde qui est sous dominance des apports sédimentaires de
l’Amazone. L’espace côtier est fortement influencé par le transport sédimentaire longshore sous
forme de vase fluide. Ces dépôts, qui peuvent atteindre plusieurs dizaines de centimètres par
cycle de marée, affectent à la fois les écosystèmes côtiers et les activités anthropiques (transport maritime, tourisme, aménagement littoral,...). Caractériser les processus de formation et
de transport des vases fluides est une thématique à forts enjeux qui permettrait de répondre
aux problèmes socio-économiques actuels mais aussi d’avoir une vision prédictive de l’évolution
littorale en réaction aux changements climatiques et océaniques.
En Guyane française les processus de formation et de transport de vase fluide le long du littoral restent encore du domaine de la spéculation. Les résultats présentés détailleront un cas
d’étude en France métropolitaine (estuaire de la Vilaine, Bretagne Sud) dont la méthodologie
est transposable sur les vasières intertidales de Guyane.
Le protocole utilisé repose principalement sur le déploiement et sur une paramétrisation particulière d’altimètres à ultrasons. Dans un premier temps, les phases brutales et massives de
dépôts de vase fluide jusqu’à 30 cm sont mesurées. Dans un second temps leur devenir à travers
les processus de compaction et d’érosion par liquéfaction est enregistré par calibration spécic
fique des seuils de sensibilité des AltusNKE.
Dans un dernier temps, le positionnement de
c
plusieurs AltusNKE
sur un secteur cible permet d’estimer les volumes mobilisés, les zones
sources et les zones puits en fonction de la morphologie générale par rapport au niveau moyen
des marées et en fonction des facteurs forçants (houle, marée, vent). L’estuaire de la Vilaine,
tout comme les côtes guyanaises, est caractérisé par une dynamique particulière des vases fluides
avec d’importants dépôts vaseux. Ceux déposés au large sont par la suite remis en suspension
par le vent, la houle et les courants de marée entrainant des épisodes de sédimentations sur les
c
zones intertidales pouvant atteindre 6 m en 30 ans. Les mesures altimétriques par AltusNKE
sur plusieurs années couplées à la modélisation menées dans l’estuaire de la Vilaine ont mis en
évidence des phases de dépôts massifs et d’érosion par liquéfaction en fonction de l’intensité
des facteurs forçants. Cette approche a principalement mis en évidence les relations entre la
∗
Intervenant
21
dynamique des vases fluides et des séquences climatiques particulières considérées comme étant
les conséquences actuelles des changements climatiques (tempêtes hivernales, temps calmes estivaux, modification du régime de houle et augmentation du niveau marin de 12 cm depuis 50 ans).
Cette approche pourrait être menée sur les côtes guyanaises afin de mieux comprendre la dynamique des vases fluides et surtout leur rôle dans l’évolution des systèmes littoraux tropicaux
soumis aux changements climatiques par la modification des grands cycles climatiques (ZCIT,
ENSO, NAO) mais aussi des conditions océaniques (niveau marin, houle).
Mots-Clés: Altimétrie Altus, Estuaire de la Vilaine, Hs, Guyane, érosion, dépôts
22
Classification Climatique de le Cours Inférieur
de la Rivière Oiapoque Selon Méthodologie
K´’oppen
Themístocles Gomes Sobrinho
1
∗† 1
, Pablo Coelho
, Laysa Santana 2 , Valdenira Santos
∗
2
1
2
Résumé: Cet article présente la classification climatique de le cours inférieur de la Rivière
Oiapoque selon Méthodologie de K´’oppen & Geiger (1928), compte tenu des l’importance des caractéristiques climatiques de la région pour le développement scientifique, social et économique.
Ceci est un bassin hydrographique situé à (N, NW) de l’État d’Amapá et à (S, SE) du territoire d’outre-mer de la Guyane Française, et son cours principal de la ligne frontière entre
le Brésil (Amapá) et la France (Guyane Française). Les données climatiques utilisées dans
l’exécution de cette recherche étaient: la température et les précipitations. Ce sont des données
secondaires fournies par le Instituto Nacional de Meteorologia (INMET/MAPA), par l’Agência
Nacional de Água – ANA, dans le système HIDROWEB et par le Núcleo de Hidrometeorologia e Energias Renováveis (NHMET-AP/IEPA). Les indices de température analysés sont liés
à des stations météorologiques, conventionnel et automatique, des séries chronologiques (19591968, 1971-1975) e (1997-1998, 2006-2014) respectivement. Les précipitations, ainsi que le laps
de temps de l’analyse, se réfèrent à des positions: OMM 8351000 (1959-1975), OMM 8351001
(2004-2006) et OMM 8351002 (1981-2013), chacun d’eux est entré dans la limite naturelle du
bassin hydrographique. La température annuelle moyenne compensée de le cours inférieur de la
Rivière Oiapoque atteint 26,4 ± 0,05o C. Valeurs de température mensuelle moyenne et annuels
montrent une amplitude thermique bas, allant de 25,5 ± 0,05◦C (février) a 27,7 ± 0,06 ◦C (octobre), et le trimestre le plus torride se produisant dans les mois (sep–oct–nov) et les valeurs
thermiques plus petits à (jan–fév-mar), suggérant une influence plus grande de l’solstice d’été
et l’hiver de l’hémisphère nord pour la région d’étude. La moyenne annuelle des précipitations
accumulées dans les trois stations analysées atteint: 3390,1 ± 86,57 mm (OMM 8351000), 3326,6
± 172,11 mm (OMM 8351001) et 3256,9 ± 22,41 mm (OMM 8351002). Le trimestre avec la
plus forte concentration des précipitations se produit d’Avril à Juin (1327 ± 16,02 mm), il ne
est le mois de mai le plus humide (542,39 ± 5,47 mm), correspondant à 16,65% le total des
précipitations dans l’année. Le trimestre de moins pluies comprend la période d’Août à Octobre
(195,87 ± 4,81 mm), il est le mois de Septembre le plus sec, avec une accumulation moyenne
∗
†
Intervenant
23
mensuelle de 36,1 ± 1,01 mm, ce qui équivaut à 1,10% du total cumulatif de pluie. Toutes
les stations ont montré le même microclimat (Ami) selon la méthode de K´’oppen, caractérisé
comme un climat tropical avec de fortes pluies, température de mois le plus froid supérieur a
18◦C et le mois le plus chaud supérieur à 22◦C, présentant une brève saison sèche (sep-oct) et
pluie modéré à fort pendant le reste de l’année. On espère que les données présentées peuvent
motiver d’autres études, en particulier ceux liés au flux et reflux du bassin en question. Un autre
facteur important à considérer concerne la dynamique des masses d’air dans les années typiques
et atypiques, en essayant de comprendre la variation de la ZCIT sous l’influence d’El Niño et La
NiñaMots-Clés:
dans la zone
géographique
du bassin
de laInférieur,
Rivière Oiapoque,
Oiapoque.K´’oppen.
Classification
Climatique,
Cours
24
The climatic classification of the lower course
of the Oiapoque river’s basin according to the
K´’oppen methodology
Themístocles Gomes Sobrinho
∗ 1
, De Oliveira Santana Laysa†
1
INTRODUCTION
This paper presents the climatic classification of the lower course of the Oiapoque river’s basin
according to the methodology of Koppen & Geiger (1928); Koppen (1936). This is a watershed
located in the N, NW of the state of Amapá and S, SE overseas territory of French Guiana, being
the main course of the frontier line between Brazil (Amapá) and France (French Guiana). The
climate data used in the execution of this research were: temperature and pluviometry. These
secondary data, provided by the National Institute of Meteorology (INMET / MAP), the National Water Agency - ANA, through HIDROWEB system and the Center for Hydrometeorology
and Renewable Energy (NHMET-AP / IEPA). The data relating to temperature were extracted
from the weather stations, conventional and automatic, historic series (1959-1968, 1971-1975)
and (1997-1998, 2006-2014) respectively located on the outskirts of Oiapoque city, Amapá. The
pluviometric values, as well as the time band analysis, refer to the posts: WMO 8351000 (1959 to
1975), WMO 8351001 (2004-2006) and WMO 8351002 (1981-2013), all inserted into the natural
boundary of the Oiapoque river’s basin.
RESULTS
The average annual temperature compensated to the estuary of the Rio Oiapoque corresponds
to 26.4 ± 0.05 ◦ C. Monthly and annual average temperature values show a low thermal amplitude, ranging from 25.5 ± 0.05 ◦ C (February) to 27.7 ± 0.06 ◦ C (October). The most torrid
trimester occurs in the months (Sept-Oct-Nov) and the lower thermal values (Jan-Feb-Mar).
The cumulative average annual precipitation in the three stations analyzed reached: 3390.1 ±
86,57mm (OMM 8351000), 3326.6 ± 172,11mm (OMM 8351001) and 3256.9 ± 22,41mm (OMM
8351002). The wettest trimester is from April to June (1327 ± 16.02 mm), and the month of
May the wettest (542.39 ± 5.47 mm), corresponding to 16.65% of total precipitation for the
year. The less rainy trimester includes the time frame from August to October with 195.87
± 4.81 mm, and the month of September the driest with an average monthly accumulation of
36.1 ± 1,01mm, which is equivalent to 1, 10% of total accumulated rain. the climatic classification of the lower course of the Oiapoque river presents the weather (Ami) according to
Koppen methodology characterized as a tropical climate with heavy rains and poorly distributed
∗
†
Intervenant
25
with the coldest month temperature above 18 ◦ C and the hottest month above 22 ◦ C. This
climate has a short dry season (Set-Oct) and moderate to intense rains during the rest of the year.
CONCLUSIONS
- The lower course (estuary) of the Oiapoque river has an annual average temperature of 26.4 ◦
C compensated;
- The average annual precipitation is between 3256,9mm to 3390mm, with the wettest occurring
in trimester (April-May-Jun) and the driest (Aug-Sep-out);
- The climate is considered (Ami) according to Koppen methodology.
REFERENCES
ANA - Agencia Nacional de Aguas. Disponível em: http://hidroweb.ana.gov.br Acesso em:
02 set. 2015
INMET, Instituto Nacional de Meteorologia. Disponível em: http://www.inmet.gov.br/portal/index.php?r=bdm
Acesso em: 20 set. 2015
K´’OPPEN, W.; GEIGER, R. Klimate der Erde. Gotha: Verlag Justus Perthes. Wall-map
150cmx200cm. 1928.
K´’OPPEN, W.: Das geographisca System der Klimate, in: Handbuch der Klimatologie, edited
by: Koppen, W. and Geiger, G., Born-traeger, 1–44, 1936
NHMET - Núcleo de Hidrometeorologia e Energia Renováveis, IEPA, Disponível em: http://www.iepa.ap.gov.br/
Acesso em: 20 set. 2015
Mots-Clés: Classification Climatique, Cours Inférieur, Oiapoque, K´’oppen
26
Dynamique et rôle des vases fluides intertidales
dans l’évolution morphodynamique du littoral
guyanais
Evelyne Goubert
1
∗† 1
, Erwan Gensac
1
Géosciences Marines et Géomorphologie du Littoral (GMGL) – UMR CNRS 6538 LDO-GMGL –
France
La dynamique des vases intertidales jouent un rôle important dans le fonctionnement des
littoraux en favorisant soit l’accrétion, la stabilisation ou l’érosion des zones intertidales aussi
bien dans les systèmes tempérés que dans les systèmes. Le littoral de Guyane fait partie de
la plus longue côte vaseuse au monde qui est sous dominance des apports sédimentaires de
l’Amazone. L’espace côtier est fortement influencé par le transport sédimentaire longshore sous
forme de vase fluide. Ces dépôts, qui peuvent atteindre plusieurs dizaines de centimètres par
cycle de marée, affectent à la fois les écosystèmes côtiers et les activités anthropiques (transport maritime, tourisme, aménagement littoral,...). Caractériser les processus de formation et
de transport des vases fluides est une thématique à forts enjeux qui permettrait de répondre
aux problèmes socio-économiques actuels mais aussi d’avoir une vision prédictive de l’évolution
littorale en réaction aux changements climatiques et océaniques.
En Guyane française les processus de formation et de transport de vase fluide le long du littoral
restent encore du domaine de la spéculation. Les résultats présentés détailleront un cas d’étude
en France métropolitaine (estuaire de la Vilaine, Bretagne Sud) dont la méthodologie est transposable sur les vasières intertidales de Guyane.
Le protocole utilisé repose principalement sur le déploiement et sur une paramétrisation particulière d’altimètres à ultrasons. Dans un premier temps, les phases brutales et massives de
dépôts de vase fluide jusqu’à 30 cm sont mesurées. Dans un second temps leur devenir à travers
les processus de compaction et d’érosion par liquéfaction est enregistré par calibration spécifique
c
des seuils de sensibilité des AltusNKE.
Dans un dernier temps, le positionnement de plusieurs
c
AltusNKE
sur un secteur cible permet d’estimer les volumes mobilisés, les zones sources et les
zones puits en fonction de la morphologie générale par rapport au niveau moyen des marées et en
fonction des facteurs forçants (houle, marée, vent). L’estuaire de la Vilaine, tout comme les côtes
guyanaises, est caractérisé par une dynamique particulière des vases fluides avec d’importants
dépôts vaseux. Ceux déposés au large sont par la suite remis en suspension par le vent, la houle
et les courants de marée entrainant des épisodes de sédimentations sur les zones intertidales pouc
vant atteindre 6 m en 30 ans. Les mesures altimétriques par AltusNKE
sur plusieurs années
couplées à la modélisation menées dans l’estuaire de la Vilaine ont mis en évidence des phases de
dépôts massifs et d’érosion par liquéfaction en fonction de l’intensité des facteurs forçants. Cette
approche a principalement mis en évidence les relations entre la dynamique des vases fluides et
∗
†
Intervenant
27
des séquences climatiques particulières considérées comme étant les conséquences actuelles des
changements climatiques (tempêtes hivernales, temps calmes estivaux, modification du régime
de houle et augmentation du niveau marin de 12 cm depuis 50 ans).
Cette approche pourrait être menée sur les côtes guyanaises afin de mieux comprendre la dynamique des vases fluides et surtout leur rôle dans l’évolution des systèmes littoraux tropicaux
soumis aux changements climatiques par la modification des grands cycles climatiques (ZCIT,
ENSO,
NAO) mais
conditions océaniques (niveau marin, houle).
Mots-Clés:
vaseaussi
fluide,des
morphodynamique
28
Evolution Holocene of Belt Southern Lake,
Coastal Plain of Amapa, Amazon Coast,
Brazil.
Kerly Jardim
1
∗ 1
UNIVERSIDADE FEDERAL DO RIO GRANDE - FURG – Brésil
The Amazon region went through a period of tectonic instability that promoted a complex
history of migration and abandonment of rivers in the Amazon during the Quaternary. Largescale changes in river systems can be related to broader environmental processes as variations of
the base level, morpho sedimentary processes, climatic and tectonic changes. North of the mouth
of the Amazon River in Cape North, initial studies have identified large paleodrainage systems.
These features are indications of significant changes in the regional drainage system, indicating
intense clogging processes, tectonic movements and local neotectonic and related changes in sea
level during the Quaternary. These paleodrainage is associated with three lakes systems: South
Lakeside System, East Lakeside System and West Lakeside System whose origin is related to
morphological evolution of the area. For the most part, these lakes have format in ox bow and
could be abandoned meanders of the river Araguari and other ancient river systems. However,
the morphogenesis of these relations paleodrainage with lake systems and current drains have
not been properly clarified. The aim of this study was to understand the Holocene evolution of
South Lakeside Belt as a subsidy to paleogeographic reconstruction of the area. The methodology involved the mapping of surface paleodrainage network from orbital and sub-orbital remote
sensing images. Coupled with the mapping were analyzed shallow seismic data and subsurface
sediment cores of radio carbon dating. These data were integrated for understanding the evolution of the southern lakes. They identified two steering systems paleodrainage N-S and NE-SW
associated with lakes Botos, Comprido de Cima, Lodão and Mutuco. The subsurface structures
of the lakes were defined from the profiling four seismic sections and three sediment cores. From
the integration of the data was possible to find evidence on the evolution of these lakes from the
sub-fund of sedimentary packages architecture. Which leads to say that they are remnants of
old storm drains that emptied into the Amapa coast and had their mouths clogged, thus causing
the drowning of these drainages and forming lakes inside the plain. The identification of these
records show evidence of recent evolution of the Amazon coastal plain, where it was possible
to characterize only the shallow stratigraphic succession. However, these registers need to be
better investigated from a larger number of subsurface data and greater depth for the further
study of the sedimentary deposit during Holocene and consequently a better understanding of
coastal evolution. New geological and geophysical investigations are being carried out to better
understand
the evolution
of thisHolocene,
coast and
trace the
paleogeography of the area.
Mots-Clés:
Lake, Evolution
Amazon
Coast
∗
Intervenant
29
Evolução holocênica do cinturão lacustre
meridional, planície costeira do Amapá, Costa
amazônica, Brasil.
Kerly Jardim
∗† 1
, Valdenira Santos
∗ ‡ 2
, Ulisses De Oliveira
∗
1
1
UNIVERSIDADE FEDERAL DO RIO GRANDE - FURG – Brésil
INSTITUTO DE PESQUISAS CIENTÍFICAS E TECNOLÓGICAS DO ESTADO DO AMAPÁ IEPA – Brésil
2
RESUMO: A região amazônica passou por um período de instabilidades tectônicas que promoveram uma história complexa de migração e abandono de rios na Amazônia durante o Quaternário. As mudanças em larga escala de sistemas fluviais podem estar relacionadas a processos
ambientais mais amplos como as variações do nível de base, processos morfossedimentares, mudanças climáticas e tectônicas. Ao norte da foz do rio Amazonas, na região do Cabo Norte,
estudos iniciais têm identificado grandes sistemas de paleodrenagens. Essas feições são indícios
de significativas mudanças no sistema de drenagem regional, indicando intensos processos de
colmatação, movimentos tectônicos e neotectônicos locais e variações relativas do nível do mar
durante o Quaternário. Estas paleodrenagens estão associadas a três sistemas de lagos: Sistema
Lacustre Meridional, Sistema Lacustre Oriental e Sistema Lacustre Ocidental cuja origem está
relacionada a evolução morfológica da área. Em sua grande maioria, estes lagos possuem formato
em ox bow e poderiam ser meandros abandonados do rio Araguari e de outros sistemas fluviais
antigos. No entanto, as relações de morfogênese dessas paleodrenagens com os sistemas de lagos
e as drenagens atuais ainda não foram devidamente esclarecidas. O objetivo geral deste trabalho
consistiu em compreender a evolução holocênica do Cinturão Lacustre Meridional como subsídio
a reconstituição paleogeográfica da área. A metodologia envolveu o mapeamento superficial da
rede de paleodrenagens a partir de imagens de sensores remotos orbitais e suborbitais. Aliado ao
mapeamento foram analisados dados de sísmica rasa, testemunhos sedimentares de subsuperfície
e datação por rádio carbono. Esses dados foram integrados para o entendimento da evolução
dos lagos meridionais. Foram identificados dois sistemas de paleodrenagens de direção N-S e
SW-NE associadas aos lagos dos Botos, Comprido de Cima, Lodão e Mutuco. As estruturas de
subsuperfície dos lagos foram definidas a partir da perfilagem de quatro seções sísmicas e três
testemunhos sedimentares. A partir da integração dos dados foi possível encontrar evidências
sobre a evolução desses lagos a partir da arquitetura dos pacotes sedimentares de subfundo. Isto
leva a afirmar que os mesmos são resquícios de antigas drenagens fluviais que desaguavam na
costa do Amapá e tiveram suas desembocaduras obstruídas, causando assim o afogamento dessas
drenagens e formando os lagos no interior da planície. A identificação desses registros mostram
∗
Intervenant
‡
†
30
evidências da evolução recente de parte da planície costeira amazônica, onde foi possível caracterizar apenas as sucessões estratigráficas superficiais. No entanto, esses registros precisam ser
melhores investigados a partir de um número maior de dados de subsuperfície e de maior profundidade para o estudo mais completo do pacote sedimentar depositado durante o Holoceno e
consequentemente um melhor entendimento da evolução costeira. Novas investigações geológicas
e geofísicas estão sendo realizadas para compreender melhor a evolução dessa costa e traçar a
paleogeografia
área.Evolução Holocênica, Costa Amazônica
Mots-Clés:da
Lagos,
31
Microfossils and environmental changes,
Maracá Islands, Amazon coast, Amapá.
Lazaro Laut ∗ 1 , Valdenira Santos 2 , João Graciano Mendonça-Filho 3 ,
Frederico Silva 3 , Virginia Martins 4 , Fabrizio Frontalini 5 , Amilcar Mendes
6
1
Universidade Federal do Estado do Rio de Janeiro (UNIRIO) – Av. Pasteur, 458, IBIO/CCET, sala
500 Urca, Rio de Janeiro - RJ – Brasil, CEP 22.240-490, Brésil
2
3
Laboratório de Palinofácies Facies Orgânica (LAFO - UFRJ) – Av. Athos da Silveira Ramos, 274 Bloco F Ilha do Fundão - Cidade Universitária. 21.949-900. Rio de Janeiro – RJ, Brasil, Brésil
4
Universidade do Estado do Rio de Janeiro (UERJ) – UERJ, Av. Sao Francisco Xavier, 524,
Maracana, 20550-900, Rio de Janeiro, Brésil
5
Universitàdegli Studi di Urbino "Carlo Bo", Dipartimento di Scienze della Terra, della Vita e
dell’Ambiente (DiSTeVA) – Via Aurelio Saffi, 2, 61029 Urbino PU, Italie
6
Museu Paraense Emílio Goeldi - Coordenação de Ciências da Terra e Ecologia (GOELDI/CCET) –
Av. Perimetral, 1901 - Terra Firme - Telefone: 55 91 3075 6272 - Cep: 66077-830 - Belém - PA - Brasil,
Brésil
The multi-proxy analysis can produce more accurate results about paleoenvironmental changes
and evolution of recent environments. Foraminifera are useful proxy as hydrodynamic bioindicators because their microfaunal abundance and composition are linked with environmental characteristics (such as currents activity, organic matter supply, oxygen changes, physicochemical
parameters ). Palynomorphs also may indicate hydrodynamics and depositional conditions of a
system. Studies using multiple proxies analysis to recognize environmental changes in Quaternary sequences in the north of Brazilian Amazon River mouth are scarce. This study represents
the first effort to qualify and quantify of the microfossils content in sediments of Quaternary
deposits, in the Maracá Islands, near Amazon River mouth, to recognize recent environmental changes in Maritime Basin of the Amazon mouth. The Maracá Islands belongs to Maracá
Ecological Station, created in 1981. This area presents the highest tides from Brazil coast,
above 8 m, with the presence of tidal bore influenced by the discharge of Amazon River. In
this work a stratigraphic section of 8.2 m was described and sampled in 39 levels to analyze
the contents of foraminifera and palynomorphs. Cluster analysis in Q-mode and R-mode based
on the relative abundance of foraminifera and palynomorphs components was employed aiming to group the samples and recognize the environmental changes along the analyzed section.
The results showed the dominance of phytoclasts (75%), with predominance of subgroups of
opaque phytoclasts bioestruturated (22%), cuticles (17%) and membranes (10%) indicating a
proximal area, with little reworking, for the deposition of the sedimentary packet. Between the
sections 80-200 cm and 540-680 cm, were identified palynomorphs of marine origin (dinocysts and
palinoforaminifera) and Devonian prasinophytes and achritarchs. The Devonian palynomorphs
indicate a source from eroded material of the Amazon Sedimentary Basin transported to the
∗
Intervenant
32
coastal area by the river flow. Nineteen species of foraminifera typical from intertidal zones and
mangroves were identified in the interval of 0-86 cm and 598-613 cm indicating, in these levels,
influence of brackish water. The cluster analysis indicated four environmental stages: Stage I
(820-650 cm) – presence mainly of structured phytoclasts suggesting continental environments;
Stages II (649-570 cm) - presence of marine palynomorphs and brackish water foraminifera indicating influence of estuarine environment; Stage III (569-120 cm) - prevalence of structured
phytoclasts, amorphous organic matter, freshwater algae and high content of organic carbon
and sulfur suggesting continental environment; Stage IV (119-0 cm) - presence of marine palynomorphs and foraminifera typical of estuarine environment. These identified stages are related
to environmental changes into a continental environment with periods of marine influence. Previous sedimentological and geochronological works in Maracá Island indicate an age of 2,000 to
1,000 years BP for peat observed into the interval of the stage III. These results indicate changes
in sea level or in the depositional conditions with temporal variation between fluvial, estuarine
and Mots-Clés:
lacustrine and/or
environment
during
the recent
past.
coastalswamp
evolution,
environmental
changes,
microfossil
33
Mise en place d’un indicateur poisson DCE
compatible pour les estuaires de Guyane
française
Mario Lepage
∗ 1
1
Institut national de recherche en sciences et technologies pour l’environnement et l’agriculture IRSTEA (FRANCE) (IRSTEA) – Institut national de recherche en sciences et technologies pour
l’environnement et l’agriculture - IRSTEA (FRANCE) – 50 avenue de Verdun, 33612 Cestas Gazinet,
France
La Directive Cadre européenne sur l’Eau (DCE) exige des états membres de se doter d’outils
d’évaluation de la qualité écologique des eaux de surface dont les estuaires. Les départements
français ultra-marins ont obtenu des délais supplémentaires pour développer leurs outils mais
aussi pour répondre aux exigences d’atteinte du bon état des masses d’eau qui étaient fixées à 2015
pour tous les états européens. C’est donc dans ce contexte que le développement d’un indicateur
poisson pour les eaux de transition de Guyane a commencé en 2013. Un premier recensement
des espèces potentiellement présentes a été réalisé à partir d’une étude bibliographique. Sur les
neuf estuaires concernés, près de 360 espèces ont été dénombrées. Ces espèces ont été regroupées
en guildes écologique, trophique, de reproduction et de position dans la tranche d’eau et 73
métriques potentielles ont été identifiées pour servir à la construction d’un indicateur poisson.
Dix sept d’entre elles ont montré une sensibilité à différentes pressions d’origine anthropique. En
2014, des essais comparatifs d’échantillonnage ont été réalisés dans l’estuaire du Sinnamary. Ils
avaient pour but d’identifier la ou les méthodes permettant de calculer les métriques potentielles
préalablement définies. Les premiers résultats révèlent que parmi 3 types d’engins de pêche testés,
le chalut à perche semble fournir les meilleurs résultats dans le cours principal de l’estuaire mais
pour l’échantillonnage des criques, le verveux à ailes est mieux adapté. Il semble également
plus pertinent d’échantillonner à la fin de la saison des pluies pour obtenir une plus grande
diversité d’espèces et pour mesurer la qualité écologique des estuaires guyanais moins soumis
à l’influence de l’Amazone à cette période. Un protocole est proposé pour la réalisation des
premiers inventaires poissons dans les estuaires de Guyane à partir de septembre 2015. Les
retours
d’expérience
permettront
d’apporter
les ajustements
Mots-Clés:
estuaire,
communauté
de poissons,
bioindication qui seront jugés nécessaires.
∗
Intervenant
34
Mise en place d’un indicateur poisson DCE
compatible pour les estuaires de Guyane
française
Mario Lepage ∗ 1 , Régis Vigouroux , Olivier Monnier , Franck Chow-Toun ,
Mathieu Rhone , Stéphanie Rey , Myriam Debris
1
Institut national de recherche en sciences et technologies pour l’environnement et l’agriculture IRSTEA (FRANCE) (IRSTEA) – Institut national de recherche en sciences et technologies pour
l’environnement et l’agriculture - IRSTEA (FRANCE) – 50 avenue de Verdun, 33612 Cestas Gazinet,
France
La Directive Cadre européenne sur l’Eau (DCE) exige des états membres de se doter d’outils
d’évaluation de la qualité écologique des eaux de surface dont les estuaires. Les départements
français ultra-marins ont obtenu des délais supplémentaires pour développer leurs outils mais
aussi pour répondre aux exigences d’atteinte du bon état des masses d’eau qui étaient fixées à 2015
pour tous les états européens. C’est donc dans ce contexte que le développement d’un indicateur
poisson pour les eaux de transition de Guyane a commencé en 2013. Un premier recensement
des espèces potentiellement présentes a été réalisé à partir d’une étude bibliographique. Sur les
neuf estuaires concernés, près de 360 espèces ont été dénombrées. Ces espèces ont été regroupées
en guildes écologique, trophique, de reproduction et de position dans la tranche d’eau et 73
métriques potentielles ont été identifiées pour servir à la construction d’un indicateur poisson.
Dix sept d’entre elles ont montré une sensibilité à différentes pressions d’origine anthropique. En
2014, des essais comparatifs d’échantillonnage ont été réalisés dans l’estuaire du Sinnamary. Ils
avaient pour but d’identifier la ou les méthodes permettant de calculer les métriques potentielles
préalablement définies. Les premiers résultats révèlent que parmi 3 types d’engins de pêche testés,
le chalut à perche semble fournir les meilleurs résultats dans le cours principal de l’estuaire mais
pour l’échantillonnage des criques, le verveux à ailes est mieux adapté. Il semble également
plus pertinent d’échantillonner à la fin de la saison des pluies pour obtenir une plus grande
diversité d’espèces et pour mesurer la qualité écologique des estuaires guyanais moins soumis
à l’influence de l’Amazone à cette période. Un protocole est proposé pour la réalisation des
premiers inventaires poissons dans les estuaires de Guyane à partir de septembre 2015. Les
retours
d’expérience
permettront
d’apporter
les ajustements
Mots-Clés:
estuaire,
communauté
de poissons,
bioindication qui seront jugés nécessaires.
∗
Intervenant
35
Groundwater processes on the French Guiana
coastal plain. A historical and prospective
ecohydrological brainstorm.
Lambs Luc
∗† 1
, Thomas Stieglitz
∗ ‡
1
‘Invisible’ groundwater processes play an important but often overlooked component of the
water cycle affecting the ecohydrology of wetland ecosystems. Much of the French Guiana coastal
plain is occupied by rainforest, freshwater swamps and marshes, and mangrove forests . But little
is known on groundwater resources and exchange processes with surface waters, i.e. swamps,
rivers and coast. Here, we brainstorm known or unknown groundwater exchange processes and
propose a toolbox consisting of stable (d18O, d2H) and radiogenic (222Rn) isotopes to study
them, with the aim to design whole-of-system groundwater studies ‘from source to sink’ in the
future.
Mots-Clés: water cycle, ground water, eco, hydrology, isotopic toolbox
∗
Intervenant
‡
†
36
Groundwater processes on the French Guiana
coastal plain. A historical and prospective
ecohydrological brainstorm.
Lambs Luc
∗ 1
1
‘Invisible’ groundwater processes play an important but often overlooked component of the
water cycle affecting the ecohydrology of wetland ecosystems. Much of the French Guiana coastal
plain is occupied by rainforest, freshwater swamps and marshes, and mangrove forests . But little
is known on groundwater resources and exchange processes with surface waters, i.e. swamps,
rivers and coast. Here, we brainstorm known or unknown groundwater exchange processes and
propose a toolbox consisting of stable (d18O, d2H) and radiogenic (222Rn) isotopes to study
them, with the aim to design whole-of-system groundwater studies ‘from source to sink’ in the
future.
Mots-Clés: groundwater, isotopes, ecohydrology
∗
Intervenant
37
Geo Coastland
Barbara Martel
1
∗ 1
Geo Coastland – Geo Coastland – France
Geo Coastland est un bureau d’études au service des territoires côtiers pour la prévention et
la gestion des risques.
La démarche de Geo Coastland est de mobiliser des expertises pluridisciplinaires pour un développement équilibré entre terre, mer et société indispensable à une adaptation du littoral aux changements climatiques.
Geo Coastland is an engineering office in the service of coastal territories for the prevention and
management of risks.
Geo Coastland’s approach is to mobilize multidisciplinary expertises for balanced development
between
land, seaGIZC,
and indispensable
company
to a coastal
adaptation
to climate
change.
Mots-Clés:
enjeux, capacité
d’adaptation,
vulnérabilité,
gestion,
prévention,
Integrated
coastal management, consultation, expertise
∗
Intervenant
38
Geo Coastland au service de la gestion intégrée
et durable des zones côtières
Barbara Martel
1
∗ 1
Geo Coastland – Geo Coastland – France
Geo Coastland est un bureau d’études, de conseils et d’expertises appliqués à la gestion intégrée des zones côtières.
La mobilisation d’experts en sciences humaines, économiques, techniques et scientifiques au sein
de Geo Coastland permet de réunir des compétences pluridisciplinaires assurant le succès d’une
gestion durable du littoral indispensable à son adaptation aux changements climatiques.
La démarche de Geo Coastland se veut innovante par une approche sur mesure, transversale,
adaptée à chaque situation en concertation avec les acteurs de terrain. La méthode déployée
permet de décomposer le processus d’intervention en 7 étapes dont le noyau central du modèle
est la vulnérabilité. Vulnérabilité qui est caractérisée, évaluer afin de définir les actions à mettre
en place pour répondre aux besoins locaux.
Un poster est proposé pour présenté l’organisation de Geo Coastland ainsi que ses offres de
services.
Mots-Clés: GIZC, risque, aléas, enjeux, capacité d’adaptation, vulnérabilité, gestion, érosion, submersion, PPRL, coût/bénéfice, délocalisation, prévention, ouvrages, plage, rechargement, psychologie
sociale
∗
Intervenant
39
Tracking the origin and dynamics of the sandy
beaches in the context of global change and
ecosystem services: a French Guiana project to
be expanded to the Brazilian window
Philippe Negrel ∗ 1 , Emmanuelle Petelet-Giraud 2 , Seyler Patrick 3 , Antoine
Gardel 4 , Edward Anthony 5 , Laure Gardel-Bernadac 6
1
2
Bureau de recherches géologiques et minières (BRGM) – Bureau de Recherches Géologiques et
Minières (BRGM) – 3 Avenue Claude Guillemin, B.P. 36009, 45060 Orléans, France
Bureau de recherche géologiques et minières (BRGM) – Ministère de l’Enseignement Supérieur et de
la Recherche Scientifique – France
3
IRD – Ministère de l’Enseignement Supérieur et de la Recherche Scientifique – France
4
CNRS – Ministère de l’Enseignement Supérieur et de la Recherche Scientifique – France
5
CEREGE – Ministère de l’Enseignement Supérieur et de la Recherche Scientifique – France
6
ForeSea – Entreprise – France
The French Guiana marine window, including rivers-estuaries-slope-shelf-deep sea basin, covers an area of 126,000 km2 and is largely influenced by water and sediments (mud and sands)
from the Amazon River, making it unique in terms of its dynamics and exceptional dimension.
Within this essentially muddy environment, sandy beaches in French Guiana are rare (15% of
the coastline) and are sensitive as sandy sedimentary stocks are limited in volume and distribution. These beaches have important economic (human settlements, roads...) asset and a unique
protective and ecological role (turtle nesting...). They are vulnerable with rapidly changing dynamics, and subject to major phases of erosion and accretion, even if no influence of climate
change have been demonstrated up to now. In recent decades, erosion has been aggravated by
sand extractions directly on the beaches and the classical sedimentology approach and coastline
investigations were ineffective to understand the origins and movement of sand. The ambition
of the project (GUIABEACH) is thus to constrain the sand transfers along the Guiana coast in
connection with the sediment supply from the Guyana Shield watersheds and external to the
Amazon.
There is also a general lack of faith amongst a large proportion of the public in the knowledge
and thus in the governance of decision-making. These main challenges to reliable knowledgedecision making can be related to the specific objectives of the project that aim to (1) identify the
mechanisms of coastal accretion and erosion associated with sand dynamics in strategic sectors
of this shoreline (coastal urbanization...) ; (2) define the relationships between rivers and the
coastal zone ; (3) elaborate a better understanding of the forcing mechanisms (marine forcing,
river flooding events, rising sea level...) and rate variability of sand migration on the coast; (4)
design a comprehensive model of coastal sands transfer and ensure its appropriation by local
authorities and professionals involved in the economic development of the region. This includes
social and human sciences approaches as well as communication actions. Local representatives
∗
Intervenant
40
will be involved from the beginning of the project and investigations will be organized to study
the social perceptions of the project results.
This idea can be expanded to the Brazilian window, in the frame of a larger project to be
built, considering the vulnerability of the coast due to storm wave attack and associated risk to
the urbanized areas. Thus a question is posed about the stability of the shoreline considering
the evidences of erosion as either a general trend of a backward shift of the coastline or only a
response to extreme events with subsequent recovery of the shoreline position.
To achieve the ambitious objectives, the project will need to combine the application of innovative geochemical tools and more classical sedimentologic approaches. It is intended to trace the
source areas of sands, by coupling several chemical and isotopic tracers on heavy minerals at the
grain scale, while up to know the study of the distribution of heavy minerals on beaches and
beach ridges sands was not sufficiently relevant to identify the sand sources. This must be combined with the quantification of the sedimentary inputs from the rivers in order to evaluate the
impact on the sand transport dynamics from catchments to shelf. In addition, a special interest
needs to be given to the study of the morphodynamics of beaches and cheniers along the coast
and to identify fine-scale mechanisms involved in morphodynamic shoreline adjustments and segregation of sand. All the results could therefore be aggregated in an integrative model of sand
behavior from inland to the continental shelf. The use and social perceptions of beaches could
be investigated through an analysis of pressures on the sandy resources and their societal and
structural reasons. Obviously, the results of the project should be transferred and disseminated
towards regional authorities and stakeholders involved in management planning and economic
development
of the
Mots-Clés:
sandareas.
transfers, isotope geochemistry, heavy minerals, sedimentologic approaches
41
French Guiana stranding network
implementation
Claire Pusineri ∗ 1 , Damien Chevallier , Michel Nalovic , Benoit De Thoisy ,
Michel Vély , Rachel Berzins , Olivier Bongard , Alexandre Habert ,
Amandine Bordin , Laurent Kelle , Willy Dabin
1
Association Ocean Science Logistic (OSL) – 14-16 rue Cresson, 97310 KOUROU, Guyane française
La Guyane est un site majeur de ponte pour les tortues marines et accueille des populations relativement abondantes et diversifiées de mammifères marins. Ces espèces emblématiques
restent encore peu connues sur le territoire, alors même qu’elles sont de plus en plus menacées
par les activités d’origine anthropique (captures accidentelles, diminution des ressources alimentaires, dégradation des habitats : pollution physique, chimique, acoustique).
Dans ce contexte, les organismes guyanais impliqués dans la conservation du milieu marin ont
créé en 2014 le Réseau de suivi des Echouages de mammifères marins et de tortues marines de
Guyane (REG), en partenariat avec la DEAL de Guyane et le Réseau National des Echouages
(RNE). L’objectif de ce réseau est d’améliorer les connaissances sur les causes de mortalité des
tortues marines et des mammifères marins en Guyane.
Le REG compte aujourd’hui 25 membres appartenant pour la plupart à des organismes travaillant en Guyane sur des thématiques liées à la Biologie de la conservation: le WWF, les
associations Kwata, SOS Faune Sauvage, OSL (Ocean Science & Logistic) et Megaptera, mais
aussi le CNRS (Centre National de La Recherche Scientifique), l’ONCFS (Office National de
La Chasse et de la Faune Sauvage), les Réserves Naturelles de l’Amana (RNA) et du Grand
Connétable (RNC) et le CRPMEM de Guyane (Comité Régional des Pêches Maritime et des
Elevages Marins).
Afin d’assurer la qualité et la traçabilité des données collectées, des protocoles spécifiques à
la Guyane ont été établis sur la base des protocoles les plus couramment utilisés aux niveaux
national et international. Les membres du réseau ont été formés à ces protocoles et se sont engagés à les suivre en signant la charte du réseau. Des outils de gouvernance ont été mis en place
avec un comité de pilotage qui supervise l’application de cette charte et un animateur qui assure
la coordination du réseau. Des actions de communication sont menées auprès du grand public
pour faire découvrir ce réseau et encourager la population guyanaise à l’alerter rapidement en
cas d’échouage. Enfin, au vu des enjeux de conservation de ces espèces à l’échelle du bassin, des
collaborations ont aussi été développées avec les pays voisins, en particulier par l’intermédiaire du
réseau MamaCocoSea (Marine Mammals Conservation Corridor for Northern South-East America).
Depuis janvier 2014, les membres du REG sont intervenus sur 6 échouages de mammifères marins
et 70 échouages de tortues marines. Tous les mammifères marins étaient des sotalies (Sotalia
∗
Intervenant
42
guianensis). Parmi les tortues marines, on trouve 26 tortues vertes (Chelonia midas), 25 tortues
luth (Dermochelys coriacea) et 19 tortues olivâtres (Lepidochelys olivacea). Les examens ont
révélés une majorité de causes de mortalité liée à des captures accidentelles, induites le plus
souvent
par la pêche
illicite,
non déclarée
et non réglementée
Mots-Clés:
stranding
network,
marine mammals,
sea turtles, (INN)
sotalia aux filets.
43
Présentation du Réseau de suivi des Echouages
de Guyane
Claire Pusineri ∗ 1 , Damien Chevallier 2 , Michel Nalovic 3 , Benoît De
Thoisy 4 , Michel Vély 5 , Rachel Berzins 6 , Olivier Bongard 7 , Alexandre
Habert 8 , Amandine Bordin 9 , Laurent Kelle 10 , Willy Dabin 11
1
Association Ocean Science Logistic (OSL) – 14-16 rue Cresson, 97310 KOUROU, Guyane française
2
Centre National de la Recherche Scientifique (CNRS) – Guyane française
3
Comité Régional des Pêches Maritime et des Elevages Marins (CRPMEM) – Guyane française
4
Association Kwata – Guyane française
5
Association Megaptera – Guyane française
6
Office National de la Chasse et de la Faune Sauvage (ONCFS) – Guyane française
7
Association SOS Faune Sauvage – Guyane française
8
Réserve Naturelle de l’Amana (RNA) – Guyane française
9
Réserve Naturelle du Grand Connétable (RNC) – Guyane française
10
WWF – Guyane française
11
Observatoire Pelagis, Université de La Rochelle – Guyane française
La Guyane est un site majeur de ponte pour les tortues marines et accueille des populations relativement abondantes et diversifiées de mammifères marins. Ces espèces emblématiques
restent encore peu connues sur le territoire, alors même qu’elles sont de plus en plus menacées
par les activités d’origine anthropique (captures accidentelles, diminution des ressources alimentaires, dégradation des habitats : pollution physique, chimique, acoustique). Dans ce contexte,
les organismes guyanais impliqués dans la conservation du milieu marin ont créé en 2014 le
Réseau de suivi des Echouages de mammifères marins et de tortues marines de Guyane (REG),
en partenariat avec la DEAL de Guyane et le Réseau National des Echouages (RNE). L’objectif
de ce réseau est d’améliorer les connaissances sur les causes de mortalité des tortues marines
et des mammifères marins en Guyane. Le REG compte aujourd’hui 25 membres appartenant
pour la plupart à des organismes travaillant en Guyane sur des thématiques liées à la Biologie
de la conservation : les associations WWF, Kwata, SOS Faune Sauvage, OSL (Ocean Science
& Logistic) et Megaptera, mais aussi le CNRS (Centre National de La Recherche Scientifique),
l’ONCFS (Office National de La Chasse et de la Faune Sauvage), les Réserves Naturelles de
l’Amana (RNA) et du Grand Connétable (RNC) et le CRPMEM de Guyane (Comité Régional
des Pêches Maritime et des Elevages Marins). Afin d’assurer la qualité et la traçabilité des données collectées, des protocoles spécifiques à la Guyane ont été établis sur la base des protocoles les
plus couramment utilisés aux niveaux national et international. Les membres du réseau ont été
formés à ces protocoles et se sont engagés à les suivre en signant la charte du réseau. Des outils
de gouvernance ont été mis en place avec un comité de pilotage qui supervise l’application de
cette charte et un animateur qui assure la coordination du réseau. Des actions de communication
sont menées auprès du grand public pour faire découvrir ce réseau et encourager la population
guyanaise à l’alerter rapidement en cas d’échouage. Depuis janvier 2014, les membres du REG
sont intervenus sur 6 échouages de mammifères marins et 70 échouages de tortues marines. Tous
∗
Intervenant
44
les mammifères marins étaient des sotalies (Sotalia guianensis). Parmi les tortues marines, on
trouve 26 tortues vertes (Chelonia midas), 25 tortues luth (Dermochelys coriacea) et 19 tortues
olivâtres (Lepidochelys olivacea). Les examens ont révélés une majorité de causes de mortalité
liée à des captures accidentelles, induites le plus souvent par la pêche illicite, non déclarée et non
réglementée (INN) aux filets. Enfin, au vu des enjeux de conservation de ces espèces à l’échelle
du bassin, des collaborations ont aussi été développées avec les pays voisins, en particulier par
l’intermédiaire du réseau MamaCocoSea (Marine Mammals Conservation Corridor for Northern
South-East
America).
Mots-Clés:
échouage, réseau, mammifères marins, tortues marines
45
Stability of the muddy banks from Ponta of
Marrecal (Brazil) to Comté river (French
Guiana), Amazon coast
Laysa Santana ∗ 1,2 , Antoine Gardel ∗ † , Valdenira Ferreira Dos Santos ∗
Odete Fátima Machado Da Silveira ∗ § , Franck Dolique ∗ ¶ , Amilcar
Carvalho Mendes ∗ k
‡
,
1
- IEPA/NuPAq (IEPA/NuPAq/LASA) – Rod. Juscelino Kubitschek KM-10 - Fazendinha CEP:
68.903-419 /68.903-197 - Macapá - Amapá - Brasil Fone: (96) 3212-5358, Brésil
2
Laboratório de Sensoriamento Remoto e Análises Espaciais Aplicado a Ambientes Aquáticos (LASA)
– Rod. Juscelino Kubitschek KM-10 - Fazendinha CEP: 68.903-419 /68.903-197 - Macapá - Amapá Brasil, Brésil
The knowledge of the dynamics of the formation, structuring and migration of muddy banks
is important to understand the dynamics of structuring and modification of coastal ecosystems
north of the mouth of the Amazon river. Even with having several Works performed along the
Guyana coast, the knowledge of the area which originate the mud banks is scarce, located on
the boarder between Brazil and French Guyana. This work was developed under the project
Ose GuyAmapá - Coastal Group, and the aim is finding indicators that can be used for analysis
of coastal changes at mud cape region. The work considered morphological and geographic
features (shape and the exposed area of the muddy banks) to understand their evolution in the
segment between the Ponta of Marrecal (Brazil) and the Comté River’s mouth (French Guiana).
The study was conducted using a set of 28 scenes from the series of Landsat satellite images,
corresponding to a time series of 16 years. All scenes correspond to period of low rainfall and lower
river discharge in the Amazon (September to November). To choose the scenes were adopted
low cloud cover criteria and different stages of exposure of muddy banks in different tidal ranges.
The information tidal amplitude used refer to board Larivoir harbor tide, French Guiana, and
correspond to the dates of the scenes used. The typology of the muddy banks was extracted
from the Digital Image Processing (PDI) and supervised classification in range of banks. The
exposed area of banks in each scene was interpolated for intervals of the analyzed time series
(1997, 2004 and 2013). The results indicate that the migration of the mud banks is NW, following
the direction of the coast. The áreas of greatest exposure of mud banks were found on the ponta
of Cape Orange, Ponta of Mosquito, Ponta Coumarouman and Kaw River’s mouth. The less
esposure areas were the Ponta of Marrecal, Cape Cassiporé and Ponta Bruyere. There weren’t
evidences of the depositicon of banks in the channels at mouth of stuaries, only in the margins,
∗
Intervenant
‡
§
¶
k
†
[email protected]
[email protected]
[email protected]
[email protected]
46
this caracteristic indicate the sediments migrate from a cape to another. However, in the Ponta
of Mosquito at Oiapoque River’s mouth, the exposure area of mud bank persiste along the study
period, indicating continuous accretion process. Throughout the period analyzed, a significant
exposure area of the mud banks with spits occurs near the Kaw river’s mouth. The correlation
between the tide data and the exposure area of the banks shows the esposed area of the mud
banks increased in all analyzed patch. Nevertheless, along the coast on the Brazilian side, the
exposed area increased a thousandfold. The results have crucial information to aid in managing
the cross-border coastal zone, however, a greater volume of data and longer time series is still
necessary to continue the analysis, as well as expand the methodology entire stretch of muddy
banks, to understand not only the dynamics of migration muddy banks but also their probable
causes.
Mots-Clés: Muddy banks, migration, Amazon coast
47
sdfwa
Laysa Santana
1
∗ 1,2
2
asdfas
Mots-Clés: AEWRF
∗
Intervenant
48
Stability of the mud banks from Ponta of
Marrecal (Brazil) to Comté river (French
Guiana), Amazon coast
Laysa Santana ∗ 1,2 , Antoine Gardel ∗ † , Valdenira Ferreira Dos Santos ∗
Odete Fátima Machado Da Silveira ∗ § , Franck Dolique ∗ ¶ , Amilcar
Carvalho Mendes ∗ k
‡
,
1
2
O conhecimento da dinâmica de formação, estruturação e migração dos bancos lamosos é importante para compreender a dinâmica de estruturação e modificação dos ecossistemas costeiros
ao norte da foz do rio Amazonas. Apesar, dos vários trabalhos realizados ao longo do litoral
guianense, pouco se conhece sobre a área onde se originam esses bancos, localizado na fronteira
do Brasil com a Guiana Francesa. O presente trabalho foi desenvolvido no âmbito do projeto Ose
GuyAmapá – Grupo Litoral, com o intuito de encontrar indicadores para análise de mudanças
costeiras na região dos cabos lamosos. O trabalho considerou elementos morfológicos e geográficos (forma e a área de exposição dos bancos lamosos) para entender seus estados de evolução no
trecho compreendido entre a Ponta do Marrecal (Brasil) e a foz do rio Comté (Guiana Francesa).
O trabalho foi desenvolvido utilizando um conjunto de 28 cenas da série de imagens do Satélite
Landsat, correspondendo a uma série temporal de 16 anos. Todas as cenas correspondem a
período de baixa pluviosidade e menor descarga fluvial na Amazônia (Setembro a Novembro).
Para escolha das cenas foram adotados critérios de baixa cobertura de nuvens e diferentes estágios de exposição dos bancos lamosos, em diferentes amplitudes de maré. As informações de
amplitude maré utilizadas referem-se a tábua de maré do porto de Larivoir, Guiana Francesa
e, correspondem as datas das cenas utilizadas. A tipologia dos bancos lamosos foi extraída a
partir do Processamento Digital de Imagens (PDI) e classificação supervisionada nas áreas de
ocorrência dos bancos. A área exposta dos bancos em cada cena foi interpolada para os intervalos da série temporal analisada (1997, 2004 e 2013). Os resultados indicam que o sentido de
migração dos bancos permaneceu em direção NO, acompanhando a direção da costa. As áreas
de maior exposição dos bancos lamosos foram encontradas na ponta do Cabo Orange, Ponta do
Mosquito, Ponta Coumarouman e foz do rio Kaw. As áreas com menor exposição foram a Ponta
∗
Intervenant
‡
§
¶
k
†
[email protected]
[email protected]
[email protected]
[email protected]
49
do Marrecal, Cabo Cassiporé e Ponta Bruyére. Não foram encontradas evidências de deposição
de bancos nos canais na foz dos estuários, apenas nas margens indicando que os sedimentos
provavelmente migram de um cabo para outro. No entanto, na Ponta do Mosquito, no estuário
do rio Oiapoque, a área de exposição do banco lamoso persistiu ao longo do período analisado
demonstrando processo de acresção contínua neste ponto. Ao longo do período analisado, uma
significativa exposição da área dos bancos lamosos com formato alongado (spit) ocorre próximo
a foz do rio Kaw. A análise de correlação entre os dados de maré e área de exposição dos bancos
demonstra que a área exposta dos bancos lamosos aumentou em todo o trecho analisado. No
entanto, ao longo da costa, no lado brasileiro, a área exposta aumentou em 1.000 vezes. Os
resultados apresentam informações cruciais para auxílio na gestão na zona costeira transfronteiriça, no entanto, ainda é necessário um maior volume de dados e uma série temporal mais longa
para continuar as análises, como também expandir a metodologia todo o trecho dos bancos lamosos, visando compreender não só a dinâmica de migração dos bancos lamosos mas também suas
prováveis
causas.Mud banks, migration, Amazon coast
Mots-Clés:
50
Estabilidade dos bancos lamosos desde a Ponta
do Marrecal (Brasil) ao rio Comté (Guiana
Francesa), costa Amazônica
Laysa Santana
∗ 1,2
, Antoine Gardel ∗ † 3 , Valdenira Santos
Silveira ∗ §
∗ ‡ 4
, Odete
1
2
3
Laboratoire d’Océanologie et de Géosciences (LOG) – Université Lille I - Sciences et technologies,
CNRS : UMR8187, Université du Littoral Côte d’Opale – 28 av Foch 62930 Wimereux, France
4
O conhecimento da dinâmica de formação, estruturação e migração dos bancos lamosos é importante para compreender a dinâmica de estruturação e modificação dos ecossistemas costeiros
ao norte da foz do rio Amazonas. Apesar, dos vários trabalhos realizados ao longo do litoral guianense, pouco se conhece sobre a área onde se originam esses bancos, na fronteira do Brasil com
a Guiana Francesa. O presente trabalho foi desenvolvido no âmbito do projeto Ose GuyAmapá
– Grupo Litoral, com o intuito de encontrar indicadores para análise de mudanças costeiras na
região dos cabos lamosos. O trabalho considerou elementos morfológicos e geográficos (forma
e a área de exposição dos bancos lamosos) para entender seus estados de evolução no trecho
compreendido entre a Ponta do Marrecal (Brasil) e a foz do rio Comté (Guiana Francesa). O
trabalho foi desenvolvido utilizando um conjunto de 28 cenas da série de imagens do Satélite
Landsat, correspondendo a uma série temporal de 16 anos. Todas as cenas correspondem a
período de baixa pluviosidade e menor descarga fluvial na Amazônia (setembro a novembro).
Para escolha das cenas foram adotados critérios de baixa cobertura de nuvens e diferentes estágios de exposição dos bancos lamosos, em diferentes amplitudes de maré. As informações de
amplitude maré utilizadas referem-se a tábua de maré do porto de Larivot, Guiana Francesa
e, correspondem as datas das cenas utilizadas. A tipologia dos bancos lamosos foi extraída a
partir de técnicas de processamento digital de imagens e classificação supervisionada nas áreas
de ocorrência dos bancos. A área exposta dos bancos em cada cena foi interpolada para os intervalos da série temporal analisada (1997, 2004 e 2013). Os resultados indicam que o sentido
de migração dos bancos permaneceu em direção NO, acompanhando a direção da costa. As
áreas com maior exposição dos bancos lamosos foram encontradas na ponta do Cabo Orange,
∗
Intervenant
‡
§
†
51
Ponta do Mosquito, Ponta Coumarouman e foz do rio Kaw. As áreas com menor exposição
foram a Ponta do Marrecal, Cabo Cassiporé e Ponta Bruyére. Não foram encontradas evidências
de deposição de bancos nos canais na foz dos estuários, apenas nas margens indicando que os
sedimentos provavelmente migram de um cabo para outro. No entanto, na Ponta do Mosquito,
no estuário do rio Oiapoque, a área de exposição do banco lamoso persistiu ao longo do período
analisado demonstrando processo de acresção contínua. Ao longo do período analisado, uma
significativa exposição da área dos bancos lamosos com formato alongado (spit) ocorre próximo
a foz do rio Kaw. A análise de correlação entre a altura das marés e a área de exposição dos
bancos demonstra que a área exposta dos bancos lamosos aumentou ao longo dos anos em todo
o trecho analisado. No entanto, ao longo da costa, no lado brasileiro, a área exposta aumentou
em 1.000 vezes. Os resultados apresentam informações cruciais para auxílio ao entendimento
da dinâmica costeira na zona costeira transfronteiriça, no entanto, ainda é necessário um maior
volume de dados e uma série temporal mais longa para as análises. É necessário ainda expandir
a metodologia todo o trecho dos bancos lamosos, visando compreender não só a dinâmica de
migração
dos bancos
também
suas prováveis
causas. morfodinâmica
Mots-Clés:
bancoslamosos
lamosos,mas
processos
costeiros,
Costa Amazônica,
52
Influence of Geomorphology Pattern on
Mangrove Establishment. A case study from
the North Cape at the Amazon river mouth,
Amapá, Brazil
Valdenira Santos ∗ 1 , Christophe Proisy 2 , Salustiano Costa-Neto , Luis
Takiyama , Francinete Facundes 1 , Laysa Santana 1
1
2
BotAnique et BioinforMatique de l’Architecture des Plantes (AMAP) – Institut national de la
recherche agronomique (INRA) : UR0931, Institut de recherche pour le développement [IRD], CNRS :
UMR5120, Centre de coopération internationale en recherche agronomique pour le développement
[CIRAD] : UMR51, Université Montpellier II - Sciences et techniques – Bd de la Lironde TA A-51/ PS
2 34398 Montpellier cedex 5, France
The evaluation of the capability of mangroves to cope with coastal changes is urgently needed.
It is especially the case of the North Cape region at the Amazon river mouth. This region is
continuously submitted to extreme hydro-sedimentary processes such as tidal bores, high coastal
currents and tidal ranges, huge mud deposits and intense erosion phases. Preliminary remotesensed observations of mangrove luxuriance in terms of extension and physiognomy surprisingly
suggest ecological flexibility properties to the fast-changing coastal environment and geomorphological characteristics. For this latter point, the coastal landscape evolution since the Holocene
period is still to be questioned especially because geomorphological changes currently observed
since 2000 are of great magnitude with, for example, the rapid closing of the Araguari river
due to sediment loads by tidal bores. Undoubtedly, there are many lessons to take in pristine
mangroves
regions.
Mots-Clés:
mangrove, coastal geomorphology, geoindicators of coastal chenges, Amazon river
mouth
∗
Intervenant
53
Influence of Geomorphology Patterns on
Mangrove Establishment: A case study from
the mouth of the Amazon River, Cape North,
Brazil
Valdenira Santos
2
∗† 1
, Christophe Proisy
, Salustiano Costa-Neto
, Luis Takiyama
, Laysa Santana
∗
∗
, Francinete Facundes
1
∗
∗
∗
1
1
2
BotAnique et BioinforMatique de l’Architecture des Plantes (AMAP) – Institut national de la
recherche agronomique (INRA) : UR0931, Institut de recherche pour le développement [IRD], CNRS :
UMR5120, Centre de coopération internationale en recherche agronomique pour le développement
[CIRAD] : UMR51, Université Montpellier II - Sciences et techniques – Bd de la Lironde TA A-51/ PS
2 34398 Montpellier cedex 5, France
Coastal areas in the mouth of the Amazon River still contain pristine and largely unknown
mangrove forests. The limited scientific exploration of this largely inaccessible region indicates
a strong relationship between geomorphological characteristics, coastal processes and mangrove
physiognomy. Nevertheless, our understanding of how the coastal landscape of the North Cape
region (on the northern bank of the Amazon River mouth) has evolved is rudimentary. This area
is especially interesting for such a study because it is subject to various coastal processes of a
unique intensity and frequency. Thus, of the correspondence between geomorphologic attributes
and mangrove characteristics may provide insights into how pristine mangroves cope with coastal
changes.
In this study we correlate the geographical distribution and physiognomy of coastal mangroves
with geomorphological features for the North Cape region. Our data are delivered from high and
∗
†
Intervenant
54
very high spatial resolution satellite images acquired, aerial photographies and geological studies.
Five sites of mangrove were identified: a) Maracá islands; b) Macarry; c) mangrove in lakes;
d) fringe mangrove, and; e) expanding mangrove along the ocean coastline. All mangroves, except those inside lakes, are subject to strong tidal currents, tidal bores and waves. In Maraca
island, which split from the continent about 1000-2000 years BP, mangroves are associated to
recent mud deposit stacking over ancient deposits of fluvial systems and are characterized by a
predominance of Avicennia germinans (L.).
In Macarry, mud bars were formed over old fluvial terraces, bordering Varador channel. Mangroves have established along the Macarry river and tidal channels. This colonization began, at
a minimum, after the disconnection of Maracá Island from the continent. Because of the strong
influence of oceanic processes, young Avicennia mangrove have had to adapt to constant and
intense erosion by waves and currents. More inside this vast region, in the lakes, mangroves are
constantly under the water in a colmated plain of approximately 680 km2 . Lakes contain numerous mangrove islands (≥10m2) composed of Rhizophora mangle L. and R. harrisonii Leechm.
Moreover, historical data indicate that the terraces that are characteristic of the seaward margin
were formed during the XVIII century when several spits closed old channels, isolating them from
the intense action of marine processes. Mangroves in this area are mainly composed of Avicennia
germinans and are frequently at higher elevations than other mangrove areas due to growing over
such muddy platforms. Such mangroves may have an important role in the preservation of the
lake ecosystem. However, they should also be considered as very fragile since they are subject
to the continuous actions of strong currents and tidal bores. Mangroves near Araguari River
mouth have expanded after successive accretion events. The mosaic pattern of mangrove forest
structure and ages in this area is broadly similar to that observed in French Guiana after mud
deposit and consolidation.
In summary, the North Cape region of the Amazon River mouth is a fascinating region for studying the capability of pristine mangrove to cope with coastal changes at different temporal scales
(years/decades/centuries). We strongly believe that many lessons may be learnt from the study
of these
’last’ wild
mangroves.
Mots-Clés:
mangrove,
coastal geomorphology, Amazon river mouth, geoindicators of coastal changes.
55
A search-matching model of fisheries
Nicolas Sanz
∗ 1,2
, Bassirou Diop†
1,2
1
Université de Guyane (UG) – Site de Troubiran, 2091 route de Baduel, BP 792, 97337, Cayenne
cedex, Guyane française
2
Centre de Recherche en Economie, Gestion, Modélisation et Informatique Appliquée (Ceregmia) –
Université des Antilles, Faculté de Droit et d’Economie, BP 7209, 97275, Schoelcher cedex, Martinique
This paper studies the implications of search activities for the working of fisheries. We develop a simple fishery matching model in which firms stochastic search for fish requires specific
resources. The equilibrium level of anthropic pressure (number of empty vessels/conserved fish
stock) exerted by firms on the fish stock is derived from their individual profit maximizing behavior. Anthropic pressure determines in turn the rate at which vessels find fish i.e. catchability,
which is therefore endogenous in our model, and the stock conservation (uncaught fish) rate,
through the dynamic equation of the latter. We then show that under open access, equilibrium anthropic pressure, fishing effort and the conservation rate heavily depend on search costs.
An empirical study of the French Guiana shrimp fishery confirms the ability of the model to
reproduce
empirical
data.search costs, bioeconomic matching model
Mots-Clés:
fisheries,
∗
†
Intervenant
56
Carbon stock and sequestration in the
Brazilian mangroves
Mario Soares ∗† 1 , Gustavo Estrada 1 , Alex Alves 2 , Viviane Fernandez 1 ,
Filipe Chaves 1 , Claudia Hamacher 1 , Cassia Farias 1 , Michelle Araujo 1 ,
Daniel Santos 1 , Marciel Estevam 1
1
Universidade do Estado do Rio de Janeiro (UERJ) – UERJ, Av. Sao Francisco Xavier, 524,
Maracana, 20550-900, Rio de Janeiro, Brésil
2
Universidade Federal do Rio de Janeiro (UFRJ) – Brésil
Several studies point to the high potential of mangrove forests for carbon storage and sequestration. Considering the importance of the Brazilian mangrove area in the global context,
the Laboratory on Mangroves Research of the Rio de Janeiro State University (NEMA-UERJ)
began an extensive assessment of carbon stock and sequestration in mangroves throughout the
Brazilian coast.
Carbon stock was assessed for the three main pools of this ecosystem: aboveground biomass
(AGB), belowground biomass (BGB) and soil. For this purpose, mangrove forests located in 11
sites distributed from Santa Catarina (28◦ S) to Pará (1◦ S) were studied.To estimate the carbon
stock in AGB, 79 plots were established. After the phytosociological inventory of each plot, the
AGB was estimated using allometric models. For the mangroves located in the south and east
coasts of Brazil, previously developed specific models were used. In the case of northern coast
mangroves, multispecific models, as well as models developed for the French Guiana mangroves,
were applied. Finally, biomass was converted into carbon, using a carbon content of 44.1%.
The carbon stock in BGB was estimated by sampling 100 cores of 1 m deep. The root biomass
was converted into carbon mass considering previously determined carbon contents of 42.6% for
Avicennia spp. and Laguncularia racemosa, and 40% for Rhizophora spp. species. In mixed
forests (Rhizophora + Avicennia and/or Laguncularia) balanced carbon contents were obtained
from the relative species dominance (% basal area).
Ten cores of 1m deep were also sampled for the assessment of carbon stock in the soil of the
studied forests. The cores were fractionated into layers of 2 cm until the depth of 20 cm and
into 5 cm layers from 20 cm to the depth of 100 cm. The organic carbon was determined using a
CHN analyzer and then carbon masses of all layers of the core were summed to obtain the total
amount of carbon stock in the soil.
Carbon sequestration was only estimated, so far, for AGB. For this purpose, 20 permanent
plots were monitored annually and the increase of biomass has been converted into mass of carbon that were sequestered and incorporated into AGB.
∗
†
Intervenant
57
Based on the three carbon pools (AGB + BGB +Soil), we can observe a latitudinal gradient in the mangrove forests along the Brazilian coast, with carbon stocks of 317.56 tC.ha-1in
Santa Catarina (27◦ S), 380.21 tC.ha-1 in Rio de Janeiro (23◦ S), 413.22 tC.ha-1 in Alagoas
(10◦ S), 448.22 tC.ha-1 in Rio Grande do Norte (5◦ S) and 475.52 tC.ha-1 in Pará (1◦ S). In
turn, carbon sequestration (AGB only) ranged from 1.05 tC.ha-1.yr-1 in Santa Catarina and 2.59
tC.ha-1.yr-1 in Rio de Janeiro, to 5.07 tC.ha-1.yr-1 in Rio Grande do Norte and 4.78 tC.ha-1.yr-1
in Pará.
Considering the assessment presented here and recognizing the latitudinal variation in the structural development of mangrove forests along the Brazilian coast, as well as the area occupied by
mangroves in each coastal state of this country, the extreme importance of mangroves located
in the northern coast of Brazil becomes evident. From the total 1,225,444 ha of mangroves in
Brazil, 78% are located on the north coast. Based on the preliminary estimates presented here
for carbon density (per hectare), we can infer that the north coast mangrove forests may be
responsible for maintaining a total carbon pool of ca. 0.455 PgC and a carbon sequestration rate
in AGB of 0.005 PgC.yr-1. If we consider only the mangrove forests under direct influence of the
Amazon (Pará and Maranhão), a total carbon pool of ca. 0.222 PgC and a carbon sequestration
rateMots-Clés:
in AGB of 0.002
PgC.yr-1
estimated.
Climate
Change,are
Mitigation,
Biomass, Soil, Functions
58
Mangrove mapping using remote sensed data
crossed into GIS statistical analysis
Florent Taureau
∗† 1
, Marc Robin , Françoise Debaine
1
Littoral Environnement Télédétection Géomatique (LETG-Géolittomer) – - – Institut de Géographie
et d’Aménagement de l’Université de Nantes Campus du Tertre BP 81227 44312 NANTES CEDEX 3,
France
French mangrove forests are scattered along three oceans and composed of different species
and structures. Mangrove mapping at national scale remains a great challenge. In order to map
French mangroves, a new approach using GIS-based method and remote sensing data has been
developed. Three parameters (species composition, canopy cover and canopy mean height) are
extracted from satellite data.
The method consists in crossing statistical data from different layers into a GIS operation. Three
raster layers are computed, each of them describes one of the three parameters. The first parameter is species. The spectral and spatial signatures coming from high spectral and spatial
resolution satellite allow us to discriminate main species. The second parameter is the canopy
cover which can be computed using a vegetation index. The mean height of mangrove, which is
the last parameter, can be calculated using data such as airborne LIDAR data [1], stereoscopic
data from couples of satellite images [2], [3], or from SRTM data at a low scale [4]–[6]. The
intersection of these three raster layers allows build up a physiognomic typology of mangrove
forests.
Because of this work is in progress, only two sites have been investigated with this method
and are presented: Guadeloupe (Atlantic Ocean) and Mayotte (Indian Ocean). First results are
very promising (Kappa > 0.9).
This method is powerful because it founds in a quantitative manner a physiognomic typology
of vegetation. Multiple sources of data can be used (high or low spatial resolution), and the
method offers the possibility to map mangrove at large scale. It is therefore a useful method for
mapping Guyanese mangrove forests. Furthermore, it would allow us to go further and building
up in a simple way a habitat typology if knowledge about ecological factors were easily available
(salinity, topography, geomorphology ...).
References:
D. J. Selkowitz, G. Green, B. Peterson, and B. Wylie, ”A multi-sensor lidar, multi-spectral and
multi-angular approach for mapping canopy height in boreal forest regions,” Remote Sens. Environ., vol. 121, pp. 458–471, Jun. 2012.
∗
†
Intervenant
59
C. Vega and B. Stonge, ”Height growth reconstruction of a boreal forest canopy over a period
of 58 years using a combination of photogrammetric and lidar models,” Remote Sens. Environ.,
vol. 112, no. 4, pp. 1784–1794, Apr. 2008.
R. M. Lucas, J. C. Ellison, A. Mitchell, B. Donnelly, M. Finlayson, and A. K. Milne, ”Use of
stereo aerial photography for quantifying changes in the extent and height of mangroves in tropical Australia,” Wetl. Ecol. Manag., vol. 10, no. 2, pp. 159–173, Apr. 2002.
T. E. Fatoyinbo, M. Simard, R. A. Washington-Allen, and H. H. Shugart, ”Landscape-scale extent, height, biomass, and carbon estimation of Mozambique’s mangrove forests with Landsat
ETM+ and Shuttle Radar Topography Mission elevation data,” J. Geophys. Res., vol. 113, no.
G2, Jun. 2008.
M. Simard, V. H. Rivera-Monroy, J. E. Mancera-Pineda, E. Castañeda-Moya, and R. R. Twilley,
”A systematic method for 3D mapping of mangrove forests based on Shuttle Radar Topography
Mission elevation data, ICEsat/GLAS waveforms and field data: Application to Ciénaga Grande
de Santa Marta, Colombia,” Remote Sens. Environ., vol. 112, no. 5, pp. 2131–2144, May 2008.
M. Simard, K. Zhang, V. H. Rivera-Monroy, M. S. Ross, P. L. Ruiz, E. Castañeda-Moya, R.
R. Twilley, and E. Rodriguez, ”Mapping height and biomass of mangrove forests in Everglades
National Park with SRTM elevation data,” Photogramm. Eng. Remote Sens., vol. 72, no. 3,
pp. 299–311, 2006.
Mots-Clés: Mangroves mapping, remote sensing, GIS, physiognomic typology
60
Mapping mangrove using remote sensing data
combined into statistical GIS analysis
Florent Taureau
∗ 1
, Marc Robin , Françoise Debaine
1
Littoral Environnement Télédétection Géomatique (LETG-Géolittomer) – - – Institut de Géographie
et d’Aménagement de l’Université de Nantes Campus du Tertre BP 81227 44312 NANTES CEDEX 3,
France
French mangrove forests are scattered along three oceans and composed of different species
and structures. Mangrove mapping at national scale remains a great challenge. In order to map
French mangroves, a new approach using GIS-based method and remote sensing data has been
developed. Three parameters (species composition, canopy cover and canopy mean height) are
extracted from satellite data.
The method consists in crossing statistical data from different layers into a GIS operation. Three
raster layers are computed, each of them describes one of the three parameters. The first parameter is species. The spectral and spatial signatures coming from high spectral and spatial
resolution satellite allow us to discriminate main species. The second parameter is the canopy
cover which can be computed using a vegetation index. The mean height of mangrove, which is
the last parameter, can be calculated using data such as airborne LIDAR data [1], stereoscopic
data from couples of satellite images [2], [3], or from SRTM data at a low scale [4]–[6]. The
intersection of these three raster layers allows build up a physiognomic typology of mangrove
forests.
Because of this work is in progress, only two sites have been investigated with this method and
are presented: Guadeloupe (Atlantic Ocean) and Mayotte (Indian Ocean). First results are very
promising (Kappa > 0.9).
This method is powerful because it founds in a quantitative manner a physiognomic typology
of vegetation. Multiple sources of data can be used (high or low spatial resolution), and the
method offers the possibility to map mangrove at large scale. It is therefore a useful method for
mapping Guyanese mangrove forests. Furthermore, it would allow us to go further and building
up in a simple way a habitat typology if knowledge about ecological factors were easily available
(salinity,
topography,
geomorphology
...). sensing, GIS, physiognomic typology
Mots-Clés:
Mangrove
mapping, remote
∗
Intervenant
61
Spatio-temporal variability of benthic
biogeochemical fluxes at the sediment-air and
sediment-water interfaces in the Sinnamary
mangrove (French Guiana)
Gérard Thouzeau ∗† 1 , Jacques Clavier 1 , Thierry Le Bec 1 , Isabelle
Bihannic 1 , Manon Legoff 1 , Arthur Alt 1 , Samuel Dejoie 1 , Josephine Aller
2
, Robert Aller ∗
2
, Emma Michaud
∗
1
1
Laboratoire des Sciences de l’Environnement Marin (LEMAR) – CNRS : UMR6539, Université de
Bretagne Occidentale (UBO), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche
pour le Développement, Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER) –
Technopôle Brest-Iroise, Rue Dumont d’Urville, 29280 Plouzané, France
2
School of Marine and Atmospheric Sciences (SOMAS) – Stony Brook University Stony Brook New
York 11794-5000, États-Unis
Benthic fluxes in the Sinnamary mangrove were studied in October-November 2014 (dry
season) and June 2015 (wet season). Three intertidal study sites corresponding to 3 stages of
mangrove development (bare mud, pioneer mangrove and young mangrove) were investigated in
the Sinnamary estuary. Benthic fluxes were measured using benthic chambers; the incubations
were carried out at low and high tide in Oct-Nov 2014, but only at low tide in June 2015. Preliminary measurements in Nov. 2013 were used to define the chamber characteristics, incubation time
and water sampling inside the chambers. Both daylight and night incubations were performed for
each exposure condition. Daylight underwater incubations were carried out at zenith, whenever
possible, to estimate underwater primary production. Irradiance was recorded during daytime
incubations at low and high tide using LI-192SA and LI-193SA underwater Quantum Sensors.
CO2 fluxes were measured at low tide (LI-820 CO2 gas analyzer), while dissolved oxygen (DO;
YSI 6920v2 probes), pH, total alkalinity and nutrient fluxes (water samples) were measured at
high tide. The pH and total alkalinity values were used to calculate Dissolved Inorganic Carbon
(DIC) fluxes. Incubations in each of the 3 mangrove facies were performed in triplicates for each
exposure condition. Sediment cores were collected inside the chambers at the end of the incubations to estimate the benthic biomasses (Chlorophyll a, bacteria, meiofauna and macrofauna)
and radionuclide content, as well as for CT-Scan analysis of crab burrows. Water samples were
preserved onboard in a cooler filled with carbonic ice. Filtrations and sample preservation or
∗
†
Intervenant
62
analysis (pH) were made back to the Laboratory. Water column characteristics were monitored
using YSI 6920v2 probes and collecting water samples during a 24h survey on 30-31 Oct 2014
(subtidal channel, 3 stations along the salinity gradient) and simultaneous recordings on the 3
mangrove facies during the flood and early ebb tides on 6 Nov 2014. A 3h water survey was
performed on June 8 2015 along the salinity gradient in the Sinnamary estuary. A 12h survey
was also carried out in a single station located in the channel offshore the study area on June
9. A total of 71 series of day and night incubations (x 3 replicates) was carried out at the
sediment-air interface (SAI) of the 3 mangrove facies from October 22 to October 28, 2014, vs.
36 series of daytime incubations from June 3rd to June 5, 2015. Air incubations lasted for 4
minutes on average and were repeated every 20-30 min. Six day and night incubations (2 incubations per facies; x 3 replicates) were performed at the sediment-water interface (SWI) of the 3
mangrove facies from November 3rd to November 9, 2014. Incubation length ranged from 1h02
to 2h25 depending on site location in the intertidal zone. The results obtained for benthic fluxes
highlight strong spatial and temporal variations which will be related with benthic community
changes and daily or seasonal environmental changes in the study area. In particular, the impacts of freshwater and marine inputs on water temperature, salinity, DO % saturation (oxygen
minimum and hypoxic events), particle load, nutrients and Chl a biomass will be considered.
The impact of irradiance variations from day to day on benthic primary production at low tide
will be also addressed. A special focus will be put on the data collected during the dry season
(2014). In late October, net CO2 flux at the SAI ranged from -18.1 to -33.6 mmol m-2 h-1 during
daytime (net influx), versus 2.3 to 6.9 mmol m-2 h-1 during the night (net efflux). Net DO fluxes
at the SWI were all negative in early November (-1.6 to -6.3 mmol m-2 h-1), thus highlighting
net respiration at high tide. DIC fluxes exhibited spatio-temporal patterns which remain to be
interpreted. Chlorophyll a biomass in the sediment ranged from 45 to 547 mg m-2. Macrofauna
biomass
(except large-sized
crabs)
ranged from
0.1 to benthic
4.7 g DW
m-2.dissolved oxygen, CO2, DIC,
Mots-Clés:
French Guiana,
mangrove,
Sinnamary,
fluxes,
nutrients
63
Estimating pCO2 from remote sensing in the
Amazon river plume
Aline Valerio
1
∗† 1
, Milton Kampel 1 , Patricia Yager
2
Instituto Nacional de Pesquisas Espaciais (INPE) – Av. dos Astronautas, 1758 Jd Granja, CEP :
12227-010 São José dos Campos - SP, Brésil
2
University of Georgia (UGA) – États-Unis
Estimation of the air-sea CO2 fluxes is fundamental for the study of global carbon cycling
and climate change. River dominant coastal areas such as the Amazon river plume region can act
as CO2 pumps that transfer carbon dioxide from the atmosphere into the ocean. The magnitude
of the ocean sink can be determined using air-sea flux estimates based on in situ measurements
of the sea surface partial pressure of CO2 (pCO2). However, while atmospheric pCO2 shows
relative homogeneity, marine pCO2 varies strongly both temporarily and spatially. To overcome
this limitation, some efforts have been made for remote sensing estimation of pCO2 and it has
been noted that some parameters such as salinity and temperature are good predictors of pCO2.
The increase of the sea surface temperature (SST) generally is correlated with the increase of
the pCO2, and the salinity can be use as a tracer of river plume. Therefore the goal of this study
was to estimate pCO2 from remote sensing in the Amazon river plume region. Aquarius and
MODIS-Aqua level 2 data were used to derive sea surface salinity (SSS) and SST, respectively.
Concomitant underway measurements of pCO2, were carried out in surface waters using a nondispersive infrared CO2 gas analyzer during two ANACONDAS cruises, in September 2011 and
July 2012. The name of the ANACONDAS project is an acronym for Amazon iNfluence on
the Atlantic: CarbOn export from Nitrogen fixation by DiAtom Symbioses. In situ pCO2 and
MODIS sea surface temperature (SST) were averaged to match Aquarius sea surface salinity
data (SSS) with 100km spatial resolution. The resulting pCO2 sampling points (n= 100) varied
between 167 to 539 µatm, and the variability of the data used to averaged was less than 25%
(variability mean = 3,6%). SSS and SST data were normalized and a multiple regression was
used to relate with pCO2. The derived pCO2 was compared with the pCO2 observed during the
cruises (N = 100, R2 = 0.34, MAE = 0.10) and the result showed a poor correlation between
the remote sensing parameters and the pCO2. It was observed that the salinity below 30 psu
was not well estimated by remote sensing, with errors reaching 12 psu between the in situ and
satellite data. Therefore all the stations with SSS below 30 psu were removed from the analyses,
reducing the dataset to 45 stations. The same statistical fitting was applied and the result was
improved (n= 45, R2 = 0.70, MAE = 0.04). To obtain a better prediction of the pCO2, it was
included, besides the SST and SSS, others satellite-derived parameters at cost of a more complex
regression equation. Adding the particulate organic carbon (POC) product from MODIS-Aqua
level 2, the result is better (n = 45, R2=0.79, MAE = 0.03). This preliminary result indicate
that, regardless the Aquarius limitation in terms of a poor spatial resolution and the absence of
near coast information, a good agreement was obtained to estimate pCO2 using SSS and SST
∗
†
Intervenant
64
satellite data in the Amazon river plume region for SSS > 30 psu. This study also indicates
thatMots-Clés:
the SSS is the
main
influencing
parameter
of pCO2
in sensing
this area.
pCO2,
Amazon
river plume,
Aquarius,
remote
65
Estimating pCO2 from remote sensing in the
Amazon river plume
Aline Valerio
1
∗ 1
Instituto Nacional de Pesquisas Espaciais (INPE) – Av. dos Astronautas, 1758 Jd Granja, CEP :
12227-010 São José dos Campos - SP, Brésil
Estimation of the air-sea CO2 fluxes is fundamental for the study of global carbon cycling
and climate change. River dominant coastal areas such as the Amazon river plume region can act
as CO2 pumps that transfer carbon dioxide from the atmosphere into the ocean. The magnitude
of the ocean sink can be determined using air-sea flux estimates based on in situ measurements
of the sea surface partial pressure of CO2 (pCO2). However, while atmospheric pCO2 shows
relative homogeneity, marine pCO2 varies strongly both temporarily and spatially. To overcome
this limitation, some efforts have been made for remote sensing estimation of pCO2 and it has
been noted that some parameters such as salinity and temperature are good predictors of pCO2.
The increase of the sea surface temperature (SST) generally is correlated with the increase of
the pCO2, and the salinity can be use as a tracer of river plume. Therefore the goal of this study
was to estimate pCO2 from remote sensing in the Amazon river plume region. Aquarius and
MODIS-Aqua level 2 data were used to derive sea surface salinity (SSS) and SST, respectively.
Concomitant underway measurements of pCO2, were carried out in surface waters using a nondispersive infrared CO2 gas analyzer during two ANACONDAS cruises, in September 2011 and
July 2012. The name of the ANACONDAS project is an acronym for Amazon iNfluence on
the Atlantic: CarbOn export from Nitrogen fixation by DiAtom Symbioses. In situ pCO2 and
MODIS sea surface temperature (SST) were averaged to match Aquarius sea surface salinity
data (SSS) with 100km spatial resolution. The resulting pCO2 sampling points (n= 100) varied
between 167 to 539 µatm, and the variability of the data used to averaged was less than 25%
(variability mean = 3,6%). SSS and SST data were normalized and a multiple regression was
used to relate with pCO2. The derived pCO2 was compared with the pCO2 observed during the
cruises (N = 100, R2 = 0.34, MAE = 0.10) and the result showed a poor correlation between
the remote sensing parameters and the pCO2. It was observed that the salinity below 30 psu
was not well estimated by remote sensing, with errors reaching 12 psu between the in situ and
satellite data. Therefore all the stations with SSS below 30 psu were removed from the analyses,
reducing the dataset to 45 stations. The same statistical fitting was applied and the result was
improved (n= 45, R2 = 0.70, MAE = 0.04). To obtain a better prediction of the pCO2, it was
included, besides the SST and SSS, others satellite-derived parameters at cost of a more complex
regression equation. Adding the particulate organic carbon (POC) product from MODIS-Aqua
level 2, the result is better (n = 45, =0.79, MAE = 0.03). This preliminary result indicate that,
regardless the Aquarius limitation in terms of a poor spatial resolution and the absence of near
coast information, a good agreement was obtained to estimate pCO2 using SSS and SST satellite
data in the Amazon river plume region for SSS > 30 psu. This study also indicates that the
SSSMots-Clés:
is the main pCO2,
influencing
parameter
of pCO2
in this
area.sensing
Amazon
river plume,
Aquarius,
remote
∗
Intervenant
66
Morphodynamic survey of an embayed
rotating beach during the approach of a mud
bank: Montjoly, French Guiana
Guillaume Brunier ∗† 1 , Edward Anthony 1 , Antoine Gardel 2 , Bertrand
Millet 3 , Jules Fleury 1 , Philippe Dussouillez 1
1
Centre européen de recherche et d’enseignement de géosciences de l’environnement (CEREGE) – Aix
Marseille Université, INSU, Institut de recherche pour le développement [IRD], CNRS : UMR7330 –
Europôle Méditerranéen de l’Arbois - Avenue Louis Philibert - BP 80 - 13545 Aix-en-Provence cedex 4,
France
2
UMR CNRS 8187 LOG en délégation au CNRS Guyane – CNRS : USR3456 – Immeuble le relai. 2
av. G. Charlery. 97300 Cayenne, France
3
Institut méditerranéen d’océanologie (MIO) – CNRS : UMR7294, Université du Sud Toulon - Var,
Institut de recherche pour le développement [IRD] : UMR235, Aix Marseille Université – M.I.O. Institut
Méditerranéen d’Océanologie Campus de Luminy Case 901 13288 MARSEILLE cedex 09, France
The 1600-km-long South American coast between the Amazon and the Orinoco Deltas exhibits muddy progradation with interspersed sandy cheniers, and a 15-km-long bedrock-dominated
coast in Cayenne French Guiana, comprising embayed sandy beaches between headlands. The
morphodynamics of these beaches is controlled by rotation induced by the alongshore migration
of mud banks from the mouths of the Amazon River that generate changes in wave refraction and
incident angles, resulting in reversals in longshore drift. A conceptual four-phase cyclic model of
rotation describes this behaviour (Anthony and Dolique, 2006). Previous studies have described
this rotation using semi-quantitative methods based on photo-interpretation and field surveys.
However, complete quantification of morphological changes during a rotation phase has never
been accomplished. This work fills this gap based on a surveys of the 4 km-long Montjoly beach,
in the course of an interbank-to-bank transition phase and a ‘bank’ phase between October 2013
and October 2014.
Our method was based on innovative high-resolution morphometric surveys from air-borne Structure from Motion (SfM) photogrammetry over Montjoly beach in October 2013, March 2014 and
October 2014. We produced digital surface models (DSM) with a resolution of 10 cm/pixel and
an accuracy less than 10 cm from accurate Differential Global Positioning System (RTK DGPS)
surveys. Hydrodynamic measurements were further obtained from pressure sensors and a bathymetric survey of Montjoly bay was carried out in October 2014. We also modelled high-tide wave
propagation over the October 2014 bathymetry using the REF/DIF v2.5 open-source model.
The results show the transfer of sand from the northern part of beach to the south after the
October 2013 survey, the DSM of which shows a beach profile in the north displaying a steep
reflective slope indicative of erosion, with a narrow upper beach 50 m-wide. The southern profile
appears smoother and wider with 90 m-wide berm. The central sector of the beach represents
∗
†
Intervenant
67
a narrow pivotal zone of sediment transfer. In October 2013, waves (Wave Watch III model)
were mainly from the NE-E, generating longshore drift from south to north, contrary to field
observations. Thus, the beach was rotating under the influence of an external parameter: a mud
bank migrating alongshore. Rotation continued in March 2014 with a 30-m retreat of the berm
in the north and an advance of 40 m in the south. Between the two DSMs spaced 6 months,
the northern sector lost ≈66,000 m3 of sand and had a 2 m-high beachface erosion scarp. The
erosion processes were enhanced close to rip-rap structures due to wave refraction. In contrast,
the southern sector gained ≈22,000 m3 of sand and incipient dunes formed actively on a 120
m-wide upper beach. The October 2014 DSM shows minor morphological changes, thus indicating the end of the ‘transition’ phase around March 2014 and the beginning of the ‘bank’ phase.
The bathymetric survey showed a large mud bar 2 m-high and 100 m-wide in the nearshore zone
that dissipated wave energy. Hydrological monitoring in June and October 2014 confirms this
low-wave energy regime (Hs < 0.5 m) compared to a more energetic regime in the neighbouring
Montabo bay beach (Hs up to 1.5 m) located downdrift of the mud bank. The REF/DIF model
confirmed the strong wave energy dissipation over the mud bar, including during extreme wave
heights of 5m periods of 18 s.
Our study provides a new quantitative overview of the rare rotation process affecting the embayed beaches of Cayenne. The rapidity and intensity of the morphological and hydrodynamic
changes highlights the need for continuous and accurate monitoring of these beaches in order to
assess
the erosionBeach
hazard.
Mots-Clés:
rotation, mud banks, aerial SFM photogrammetry, bathymetric monitoring,
REF/DIF wave model
68
Morphodynamic survey of a rotating embayed
beach during the approach of a mud bank:
Montjoly, French Guiana
Guillaume Brunier ∗ 1 , Edward Anthony 1 , Antoine Gardel 2 , Bertrand
Millet 3 , Jules Fleury 1 , Philippe Dussouillez 1
1
France
2
3
Institut méditerranéen d’océanologie (MIO) – CNRS : UMR7294, Université du Sud Toulon - Var,
Institut de recherche pour le développement [IRD] : UMR235, Aix Marseille Université – M.I.O. Institut
Méditerranéen d’Océanologie Campus de Luminy Case 901 13288 MARSEILLE cedex 09, France
The 1600-km-long South American coast between the Amazon and the Orinoco Deltas exhibits muddy progradation with interspersed sandy cheniers, and a 15-km-long bedrock-dominated
coast in Cayenne French Guiana, comprising embayed sandy beaches between headlands. The
morphodynamics of these beaches is controlled by rotation induced by the alongshore migration
of mud banks from the mouths of the Amazon River that generate changes in wave refraction and
incident angles, resulting in reversals in longshore drift. A conceptual four-phase cyclic model of
rotation describes this behaviour (Anthony and Dolique, 2006). Previous studies have described
this rotation using semi-quantitative methods based on photo-interpretation and field surveys.
However, complete quantification of morphological changes during a rotation phase has never
been accomplished. This work fills this gap based on a surveys of the 4 km-long Montjoly beach,
in the course of an interbank-to-bank transition phase and a ‘bank’ phase between October 2013
and October 2014.
Our method was based on innovative high-resolution morphometric surveys from air-borne Structure from Motion (SfM) photogrammetry over Montjoly beach in October 2013, March 2014 and
October 2014. We produced digital surface models (DSM) with a resolution of 10 cm/pixel and
an accuracy less than 10 cm from accurate Differential Global Positioning System (RTK DGPS)
surveys. Hydrodynamic measurements were further obtained from pressure sensors and a bathymetric survey of Montjoly bay was carried out in October 2014. We also modelled high-tide wave
propagation over the October 2014 bathymetry using the REF/DIF v2.5 open-source model.
The results show the transfer of sand from the northern part of beach to the south after the
October 2013 survey, the DSM of which shows a beach profile in the north displaying a steep
reflective slope indicative of erosion, with a narrow upper beach 50 m-wide. The southern profile
appears smoother and wider with 90 m-wide berm. The central sector of the beach represents
a narrow pivotal zone of sediment transfer. In October 2013, waves (Wave Watch III model)
∗
Intervenant
69
were mainly from the NE-E, generating longshore drift from south to north, contrary to field
observations. Thus, the beach was rotating under the influence of an external parameter: a mud
bank migrating alongshore. Rotation continued in March 2014 with a 30-m retreat of the berm
in the north and an advance of 40 m in the south. Between the two DSMs spaced 6 months,
the northern sector lost ≈66,000 m3 of sand and had a 2 m-high beachface erosion scarp. The
erosion processes were enhanced close to rip-rap structures due to wave refraction. In contrast,
the southern sector gained ≈22,000 m3 of sand and incipient dunes formed actively on a 120
m-wide upper beach. The October 2014 DSM shows minor morphological changes, thus indicating the end of the ‘transition’ phase around March 2014 and the beginning of the ‘bank’ phase.
The bathymetric survey showed a large mud bar 2 m-high and 100 m-wide in the nearshore zone
that dissipated wave energy. Hydrological monitoring in June and October 2014 confirms this
low-wave energy regime (Hs < 0.5 m) compared to a more energetic regime in the neighbouring
Montabo bay beach (Hs up to 1.5 m) located downdrift of the mud bank. The REF/DIF model
confirmed the strong wave energy dissipation over the mud bar, including during extreme wave
heights of 5m periods of 18 s.
Our study provides a new quantitative overview of the rare rotation process affecting the embayed beaches of Cayenne. The rapidity and intensity of the morphological and hydrodynamic
changes highlights the need for continuous and accurate monitoring of these beaches in order to
assess
the erosionBeach
hazard.
Mots-Clés:
rotation, Mud banks, aerial SFM photogrammetry, bathymetric monitoring,
hydrodynamique, REF/DIF model
70
Rapid shoreline erosion induced by human
engineering on the Mana polder, western
French Guiana.
Guillaume Brunier
∗ 1
, Edward Anthony 1 , Antoine Gardel
2
1
France
2
The Guyanas coast (French Guiana, Surinam and Guiana) is the longest muddy coast in the
world (1500 km). It is under the influence of mud banks in transit from the Amazon delta in
Brazil to the Orinoco delta in Venezuela. This westward mud bank migration induces a strong
geomorphic control on the shoreline which can be summarized in terms of ”bank” (shoreline advance and wave energy dissipation) and ”inter-bank” phases (shoreline erosion by waves).
Our study site, rice polders close to Mana city (western French Guiana), is a fine example of
the exacerbation, by human activities, of the erosional dynamics on this muddy coast during
an ”inter-bank” phase. The polders cover 50,000 ha, in 200 x 600 m compartments flanked by
earth dikes and canals. They were built in the muddy Holocene coastal plain in the 1980s and
are rapidly eroding. Waves (mean significant height = 1.5 m height) consist of Atlantic swell
and local trade wind-waves, and the tidal context is semi-diurnal and meso-tidal. We conducted
an overview of historical shoreline evolution of the coast between the Organabo and La Mana
rivers, including the Mana polder, from satellite (Landsat & SPOT) and orthophotography images from 1976 to present. Then we carried out four field experiments focused on the polder
evolution between October 2013 and October 2014, comprising topographic (RTK-DGPS) and
hydrodynamic (pressure sensors) measurements.
The results show an overall erosion of _~50 m/year since 1976 on the sector between the Organabo and La Mana rivers. This shoreline dynamic is locally punctuated by mangrove fringe
advances of _~100 m/year, consecutive to the alongshore passage of a succession of 3 mud banks.
However, we monitored an intense erosion of 150 m/year that has been affecting the polders since
2001, and lesser retreat (30 to 100 m/year) of the adjacent sectors colonized by mangrove forests,
since the last ”inter-bank” phase. The erosive shoreface shows the same structure in each polder
compartment: a chenier beach which freely retreats backwards under the influence of wave overwash. The chenier retreat rate is 100 m/year and it appears to be more intense (net retreat of 45
m) during the high wave-energy season (December to March), which generates more overwashing. In front of the chenier, we observed a large (50 m) inter-tidal mud bed showing different
levels of induration and bioturbation by mangrove roots. The mud shorefaces exhibit an erosion
rate of 100 m/year on average during our study, with large spatial variations, ranging from 80
m/year in the western side of the study area, to 150 m/year in the eastern side, which is more
∗
Intervenant
71
exposed to waves. The main erosion process clearly appears to be a differential and mechanic one
determined by the degree of bioturbation and desiccation (during low tide) of muds layers. We
observed that breaking wave stresses result in the shearing of large mud blocks from networks of
bioturbated alveolar and desiccation faults, producing large erosion scars and scarps. These erosional processes are reinforced by the polder engineering structures. Cross-shore dikes segment
the shoreline and chenier deposits, and also enhance wave reflection. The absence of mangrove
colonization in these empoldered areas also implies that cheniers are not fixed by vegetation and
are therefore subject to free and rapid retreat. These polders are therefore likely to be completely
eroded in the coming years, illustrating short-sightedness in the use and management of these
muddy
coastal lands.
Mots-Clés:
Empoldered coast erosion, Mud banks, Chenier morphodynamique, Field measurements, French Guiana
72
Liste des auteurs
Aller, Josephine, 60
Aller, Robert, 60
Alt, Arthur, 60
Alves, Alex, 55
ANTHONY, Edward, 14, 65, 67, 69
anthony, edward, 38
Araujo, Michelle, 55
Barros, Marcos, 5
BARROS, MARCOS VINÍCIUS, 3
Berzins, Rachel, 17, 18, 40, 42
Bihannic, Isabelle, 60
Bongard, Olivier, 40, 42
Bordin, Amandine, 6, 7, 40, 42
brunier, guillaume, 65, 67, 69
Caldeira, Altino, 9, 11
Chaves, Filipe, 55
Chevallier, Damien, 40, 42
Chow-toun, Franck, 33
Clavier, Jacques, 60
Coelho, Pablo, 21
Coelho, Pablo Cristiano, 9, 11
Costa-Neto, Salustiano, 51, 52
Dabin, Willy, 40, 42
DE OLIVEIRA, ULISSES, 28
de Thoisy, Benoît, 42
De Thoisy, Benoit, 40
Debaine, Françoise, 57, 59
Debris, Myriam, 33
Dejoie, Samuel, 60
Delvaux, Hélène, 17, 18
Diop, Bassirou, 54
DOLIQUE, Franck, 44
Dolique, Franck, 47
Dussouillez, Philippe, 65, 67
Estevam, Marciel, 55
Estrada, Gustavo, 55
FACUNDES, Francinete, 51, 52
Farias, Cassia, 55
Fernandez, Viviane, 55
FIGUEIREDO JR, ALBERTO, 3
Figueiredo, Alberto, 5
Fleury, Jules, 65, 67
Fromard, François, 13, 14
Frontalini, Fabrizio, 30
Gainette, Anaïs, 17, 18
GALARRAGA, Damien, 15
Gardel, Antoine, 14, 38, 47, 49, 65, 67, 69
Gardel-Bernadac, Laure, 38
Gensac, Erwan, 19, 25
Gomes Sobrinhho, Themistocles Raphael, 11
Gomes Sobrinho, Themístocles, 9, 21, 23
Goubert, Evelyne, 25
Habert, Alexandre, 40, 42
Hamacher, Claudia, 55
Jardim, Kerly, 27, 28
Kampel, Milton, 62
Kelle, Laurent, 40, 42
Laut, Lazaro, 30
Laysa, de Oliveira Santana, 23
Le Bec, Thierry, 60
LE FOL, Jérôme, 15
Legoff, Manon, 60
Lepage, Mario, 32, 33
Luc, Lambs, 34, 35
Martel, Barbara, 36, 37
Martins, Virginia, 30
Mendes, Amilcar, 30
MENDES, Amilcar Carvalho, 44
Mendes, Amilcar Carvalho, 47
Mendonça-Filho, João Graciano, 30
Michaud, Emma, 60
Millet, Bertrand, 65, 67
Monnier, Olivier, 33
Nalovic, Michel, 40, 42
Negrel, Philippe, 38
Patrick, Seyler, 38
Petelet-Giraud, Emmanuelle, 38
PROISY, Christophe, 15
Proisy, Christophe, 14, 51, 52
Pusineri, Claire, 40, 42
Rey, Stéphanie, 33
Rhone, Mathieu, 33
Robin, Marc, 57, 59
ROLLAND, Konrad, 15
73
SANTANA, Laysa, 51, 52
Santana, Laysa, 9, 11, 21, 44, 46, 47, 49
Santos, Daniel, 55
SANTOS, VALDENIRA, 28
Santos, Valdenira, 3, 5, 9, 11, 21, 30, 49, 51, 52
SANTOS, Valdenira Ferreira dos, 44
Santos, Valdenira Ferreira dos, 47
Sanz, Nicolas, 54
Silva, Frederico, 30
SILVEIRA, ODETE, 49
SILVEIRA, Odete Fátima Machado da, 44
Silveira, Odete Fátima Machado da, 47
Soares, Mario, 55
Stieglitz, Thomas, 34
TAKIYAMA, Luis, 51, 52
Taureau, Florent, 57, 59
Thouzeau, Gérard, 60
Vély, Michel, 40, 42
Valerio, Aline, 62, 64
Vigouroux, Régis, 33
Walcker, Romain, 14
Yager, Patricia, 62
74
75

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