Environmental Sedimentary Atlas of the Oceanic Zone of the State of
Transcrição
Environmental Sedimentary Atlas of the Oceanic Zone of the State of
Journal Journalof ofCoastal CoastalResearch Research SI64 SI 64 pg -- pg 1348 1351 ICS2011 ICS2011 (Proceedings) Poland ISSN 0749-0208 Environmental Sedimentary Atlas of the Oceanic Zone of the State of Santa Catarina, Brazil N. O. Horn Filho†; A.D. Schmidt‡; J. L. Soares††; V. C. Diebe‡‡ and U. R. Oliveira§ † Dept. of §Instituto de Ciências ‡ Program of Post††Graduation in ‡‡Graduation in Geosciences/CNPq, Universidade Federal de Santa Catarina , Florianópolis, 88.040-970, Brazil, [email protected] graduation in Geography, Universidade Federal de Santa Catarina , Florianópolis, 88.040-970, Brazil, [email protected] Oceanography, Universidade Federal de Santa Catarina , Florianópolis, 88.040-970, Brazil, [email protected] Geography, Universidade Federal de Santa Catarina , Florianópolis, 88.040-970, Brazil, [email protected] Humanas e da Informação, Universidade Federal do Rio Grande, Rio Grande, Brazil [email protected] ABSTRACT Horn Filho, N.O.; Schmidt, A.D.; Soares, J.L.; Diebe, V.C., Oliveira, U.R. 2011. Environmental sedimentary atlas of the oceanic zone of the state of Santa Catarina, Brazil. Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), 1348 – 1351, Szczecin, Poland, ISSN 0749-0208. The state of Santa Catarina has a coastline of 538 km representing approximately 7% of the Brazilian coast. The coastline is subdivided into three sectors: north, central and south (DIEHL & HORN FILHO, 1996). This coastline is very rugged with a high diversity of beach environments, distributed in 36 coastal municipalities, as described on the Coastal Management Plan of Santa Catarina (GERCO, 2010). Sandy beaches are transitional environments and very dynamics, changing constantly through biological, hydraulic and eolic processes, having a considerable ecological and socio-economic importance. In an ecological issue, they are productive ecosystems that sustain diverse communities of organisms, such as micro fauna and macro benthos, and most invertebrate phyla as arthropods, crustaceans, mollusks and echinoderms are represented on the beaches. On a socioeconomic point of view, the beaches are important recreational areas, providing the development of the cities, as well construction of resorts, improvement on the tourist activities, trade and industry. Population growth and the increasing occupation of coastal areas and therefore the use of their natural resources, could damage such environments. The understanding of the various agents that affect formation and variability of sandy beaches is extreme important for the effective management of this environments. In this context, the Environmental Sedimentary Atlas of the Oceanic Zone of the State of Santa Catarina, Brazil, is being developed to assist in the lack of information about the coast of Santa Catarina for students, researchers and decision makers. This project aims to raise the knowledge of the textural, morphoscopical and compositional (mineralogy and biota) characteristics of beach sediments, including the collection and analysis of approximately 300 samples of backshore sediments. Specific objectives include the membership of all oceanic beaches using the existing terminology and new names; the collection of superficial samples of sediments of backshore sector; the description of geological, geomorphological, environmental and oceanographic characteristics, and the sectorization of the Santa Catarina’s coast, through the study of sedimentological characteristics observed in fieldwork. ADITIONAL INDEX WORDS: sandy beaches, environmental sedimentary atlas, Santa Catarina, Brazil. INTRODUCTION The state of Santa Catarina has a coastline of 538 km representing approximately 7% of the Brazilian coast. The coastline is subdivided into three sectors: north, between 25°57′41″S. and 26°40′S., central, between 26°40'S. and 28°S. and south, between 28°S. and 29°23'55"S. This coastline is pretty cut and with a high diversity of beach environments, distributed in 36 coastal municipalities, as described on the State Coastal Management Plan of Santa Catarina (GERCO, 2010) (Figure 1a). Currently there is high demand for coastal zone by tourists, especially during the summer months, local residents and, most recently works from the deploying port infrastructure at coastal areas. Different causes of environmental problems have been observed in the coastal zone, due to speculation, the tourism industry, among others. Need to know more and more about the geological characteristics of the sediments with biogenic and abiogenic origin. The sandy beaches are transitional environments, dynamics changing constantly through biological, hydrodynamic and eolic processes, having considerable ecological and socio-economic importance (Hoefel, 2002). In ecological issues are productive ecosystems which support diverse communities of organisms, such as macrofauna and microfauna, and many phyla of invertebrates such as arthropods, crustaceans, mollusks and echinoderms are represented on the beaches (Mclachlan, 1983). From the standpoint of socio-economic processes view, the beaches are major recreational areas, supporting the development of cities, resorts, tourism, trade and industry. The understanding of different agents which affect the formation and variability of sandy beaches is extremely important for the effective management of this environment. The knowledge about the detail Journal of Coastal Research, Special Issue 64, 2011 1348 Environmental sedimentary atlas of the oceanic zone of the State of Santa Catarina, Brazil. Figure 1. Location of Santa Catarina coast in southern Brazil. of the behavior and dynamics of environmental elements are relevant to improve the management of those natural environments. The combination of natural and anthropogenic factors on the coastal environment results in different sedimentary processes that reflect the shapes of the shoreline (Schweitzer, 2007). The processes of coastal erosion are related to the natural processes of marine dynamics are intensified more directly by the indiscriminate use of the coastline and the beach environment (Horn Filho, 2006). The causes of coastal erosion have been discussed widely in the world (Brunn, 1962; Bird, 1985; Nordstrom, 2010), nationally (Dominguez and Bittencourt, 1996; Souza et al., 2005; Dillenburg et al., 2004; Muehe, 2006) and locally (Klein et al., 1997; Amin et al., 2000; Simó and Horn Filho, 2004; Peixoto, 2007; Schweitzer, 2007; Güttler et al., 2007; Mazzer and Dillenburg, 2009; Oliveira, 2009; Araújo et al., 2010; Rudorff and Bonetti, 2010). The two main processes suggested by the authors as the cause of the erosion is the rise in sea level and negative sediment balance with natural and/or anthropogenic causes. To understand the processes of change of coastline you must have past data. In this context is being developed the "Environmental Sedimentary Atlas of the Oceanic Zone of the State of Santa Catarina, Brazil" to assist in the lack of information about the Santa Catarina coast, mainly for students, researchers and decision makers. Because there are several types of data in this study area, such as geological, geophysical, multitemporal hydrodynamic data and remote sensing products, among others, is extremely important to implement and to available a Geographical Database (GDB) to the public in general and also reseachers. The main goal of this project is to develop a GDB in order to store the available data of the study area. "Environmental Sedimentary Atlas of the Oceanic Zone of the State of Santa Catarina, Brazil". The specific objectives percolating the registration of all ocean beaches of the coast of Santa Catarina using such terminology for existing and new denominations, the collection of 300 samples from surface sediments of the sector after beach sandy beaches, the description of the geological, geomorphological, oceanographic and environmental beaches and its subsequent sectorization of the Santa Catarina coast, through the study of sediment characteristics observed in field work. The steps for carrying out the work have been ongoing since 2008. The field work has been developed in two specific routes: the southern sector, from Florianópolis to Mampituba river (bordering the Rio Grande do Sul and Santa Catarina states) and the northern sector, from Florianópolis to the Saí - Guaçú river (bordering the Paraná and Santa Catarina states), whose collections are performed sequentially from south to north in both scripts. Sampling of sandy sediments are spaced every 2 km, bringing the total at the end of the project approximately 300 samples of the backshore with about 540 km of the coast of Santa Catarina. Also are being collected sediments from the Santa Catarina and São Francisco do Sul islands, located in the central and northern sector of the state, respectively. Concomitant with the collection of sediments, the following data are obtained to compose the digital database, geographic coordinates of points, beach width (m), slope of the beach section (in degrees), height (m), wave period (s), speed of the longshore current (m/s); dominant direction of longshore current and prevailing wind direction according to Mello Filho (1991). In all seasons a series of photographs have been taken to compose the digital photographic data of the Santa Catarina coast. After collecting the sediments to the laboratory of Sedimentology, at the Universidade Federal de Santa Catarina, where the samples are prepared comprising determining the color of the sediments. The washing of the samples for removal of soluble salts, dried on an oven at temperature 60°C and quartering following the standard techniques of textural analysis (Suguio, 1973). The total organic matter determination was performed using a chemical method (H2O2 at 50%). Then, samples were washed and dried and weighed. The content of carbonate biodetritic was performed using HCl (30%), then, samples were washed, dried and weighed. After, samples were screening is done with an interval of ½ Ø for samples of sandy sediments. The data are processed by computational methods for the classification of particles in the sample, presented in mm on the scale of Wentworth (1922). The statistical data of sediment has been performed in the program SYSGRAN 3.0 (Camargo, 2006) based on classification according to the grading scale of Wentworth (1922). Triangular and diagrams of Shepard (1954) are performed too. Statistical parameters of Folk & Ward (1957) were considered: mean (Mz), median (Md), standard deviation or degree of selection (σ), skewness (Ski) and kurtosis (Kg). METHODS The studied area include the entire oceanic coast of the Santa Catarina state in order to analyze textural and compositional morphoscopical (mineralogy and biota) characteristics of 300 sediment samples from the backshore sector. The project is being developed in three phases: phase I: sediment sampling and textural analysis on the backshore sector; phase II: morphoscopic analysis of the sediments; phase III: data integration and implementation of Geographical Database (GDB) RESULTS The central and north coast of Santa Catarina is characterized by being very heterogeneous in their size distribution, with two distinct populations, fine sand and coarse sand to very coarse (Martins, 1970, Klein et al., 1999). This indicates different environments reworking the sediments. In this region there is expressive urbanization, including port activities. The data from northern and central sectors are still having been processing. Journal of Coastal Research, Special Issue XX, 2011 1349 Environmental sedimentary atlas of the oceanic zone of the State of Santa Catarina, Brazil. In turn, the south coast of Santa Catarina is characterized by having the morphology of the arc beach dissipative morphodynamic stage, fine sand, dune fields and undeveloped sporadic human occupation (Horn Filho et al., 2010). The north azimuth of the southern beaches of Santa Catarina state showed an increasing pattern from southern to northern, since the orientation of the coast form an arc, moving from the NE-SW to ENE-WSW. As for size, the samples proved dominant in the class of fine sand to very fine sand along the southern coast. The high correlation found in sediments between the average and median represents a high degree of selection and symmetrical swekness (values between -0, 1 and 0, 1) in almost all samples. Only six samples were found to be asymmetrical and tending to be negative, confirming that finer sands tend to have negative asymmetry. CONCLUSIONS The goal on the end of the project is to analyses for 538 km of sandy beaches of Santa Catarina coast with the collection and analysis of 300 samples of sediments, which will make up a digital database with its acquits, composing the collection of sediments of Santa Catarina’s coast. The samples are being stored in containers and geographically positioned in several maps of coastal municipalities belonging to the Santa Catarina State Coastal Management Plan. The 36 coastal cities are from north to south: sector 1 or north sector: Itapoá (Figure 2), Garuva, São Francisco do Sul (Figure 2), Balneário Barra do Sul, Araquari and Barra Velha, totalized 93 km of coastline; sector 2 or central-north sector: Balneário Piçarras, Penha, Navegantes (Figure 3), Itajaí, Balneário Camboriú, Camboriú, Itapema, Porto Belo and Bombinhas, totalized 134 km of coastline; sector 3 or central sector: Palhoça, Florianópolis (Figure 3), São José, Biguaçu, Governador Celso Ramos and Tijucas (Figure 3), totalized 128 km of coastline; sector 4 or central-south sector: Jaguaruna (Figure 4), Laguna (Figure 4) , Imaruí, Imbituba, Garopaba and Paulo Lopes (Figure 4), totalized 122 km of coastline; sector 5 or south sector: Passo de Torres, São João do Sul, Balneário Gaivota, Santa Rosa do Sul, Sombrio (Figure 4), Balneário Arroio do Silva, Araranguá (Figure 4) and Içara, totalized 77 km of coastline. It is also expected, through this database, contribute to environmental conservation of sandy beaches that are the most emphasize of the Brazilian coast. Figure 2. Location of Itapoá and São Francisco do Sul municipalities in coast of Santa Catarina state. Figure 3. Location of Navegantes, Tijucas and Florianópolis municipalities in coast of Santa Catarina state. Figure 4. Location of Paulo Lopes, Laguna, Jaguaruna, Araranguá and Sombrio municipalities in coast of Santa Catarina state. Journal of Coastal Research, Special Issue XX, 2011 1350 Environmental sedimentary atlas of the oceanic zone of the State of Santa Catarina, Brazil. LITERATURE CITED AMIN JR., A. H. Horn Filho, N.O. & Diehl, F.L. 2000. Geologia costeira e recursos minerais das praias Brava e dos Amores, Santa Catarina, Brasil. Anais... SIMPÓSIO BRASILEIRO SOBRE PRAIAS ARENOSAS. Itajaí. p 405-406. Araujo, R.S.; Sprovieri, F.C; Freitas, D. & Klein, A.H.F. 2010. 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Secretaria do Planejamento do Estado de Santa Catarina. 416p. Guttler, F. N.; Plácido, A.P. & Ayala, L. 2007. Comportamento morfológico da praia do rio das Pacas, Florianópolis – SC – Brasil. PerCursos, 8:72-89. Hoefel, G. F. 2002. Morfodinâmica de praias arenosas oceânicas: uma revisão bibliográfica. Itajaí: Editora da UNIVALI. 92p. Horn Filho, N. O. 2006. Ilha de Santa Catarina. In: MUEHE, D. (Ed.) Erosão e progradação do litoral brasileiro. 413-436pp. Horn Filho, N.O.; Serafim, M. B.; Soares, J. L.; Oliveira, U. R.; Schmidt, A.D.; Diebe, V. C. 2010. Caracterização morfossedimentar das praias oceânicas do setor sul do litoral de Santa Catarina. Anais... SEMANA NACIONAL DE OCEANOGRAFIA. 3p. Klein, A. H. da F.; Temme, B.; Menezes, J. T.; Diehl, F. L.; Carvalho, J. L. B. e Jabor, P. M. 1997. Comportamento morfológico de uma praia semi-protegida: praia central de Balneário Camboriú, Santa Catarina. In: CONGRESSO DA ABEQUA, 6. Resumos...Curitiba, 82-84p. Martins, 1970. Sedimentologia da ilha de Santa Catarina. Publicação especial da escola de geologia, Porto Alegre, Editora da UFRGS. p. 1-55. Mazzer, A.M & Dillenburg, S. 2009. Variações temporais da linha de costa em praias arenosas dominadas por ondas do sudeste da ilha de Santa Catarina (Florianópolis, SC, Brasil). Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS. Pesquisas em Geociências, 36 (1): 117-135. Mclachlan, A. 1983. Sandy beach ecology: a review. In: MCLACHLAN, A. & ERASMUS, T. Sandy beaches as ecosystems. Dr. W. Junk Publishers, p. 321-381. Mello Filho, E. 1991. Projeto sentinelas do mar: instruções para efetuar as observações. COPPE, Universidade Federal do Rio de Janeiro, 11p. Muehe, D. 2006. Erosão e progradação do litoral brasileiro. MUEHE, D. (ed.) Ministério do Meio Ambiente, Brasília, 145p. Nordstrom, K.F. 2010. Recuperação de praias e dunas. [tradução Silvia Helena Gonçalves] São Paulo: Oficina de Textos, 2010. 263p. Oliveira, U. R. 2009. Relações entre a morfodinâmica e a utilização em trechos da costa oceânica da ilha de Santa Catarina, SC, Brasil. Florianópolis. 222p. Tese de doutorado. Programa de Pós-graduação em Geografia. Universidade Federal de Santa Catarina. Peixoto, J. R. V. 2005. Análise morfossedimentar da praia do Santinho e sua relação com a estrutura e dinâmica da vegetação “pioneira” da duna frontal, ilha de Santa Catarina, SC, Brasil. Florianópolis. 78p. Dissertação de mestrado. Programa de Pós-graduação em Geografia. Universidade Federal de Santa Catarina. Rudorff, F. M. & Bonetti, J. 2010. Avaliação da suscetibilidade à erosão costeira de praias da ilha de Santa Catarina. Braz. Journal Aquat. Science Technol.,14(1):9-20. Schweitzer, A. 2007. Comportamento morfossedimentar do arco praial e evolução do uso do solo na praia Brava, ilha de Santa Catarina, SC, Brasil. 79p. Monografia. Geografia. Universidade Federal de Santa Catarina. Shepard, F. P. 1954. Nomenclature based on sand-silt-clay ratios. Journal of Sedimentary Petrology, 24: 241-158. Simó, D.H.; & Horn Filho, N.O. 2004. Caracterização e distribuição espacial das “ressacas” e áreas de risco na ilha de Santa Catarina. Gravel, 2: 93-103. Souza, C.R.G.; Souza Filho, P.W.M.; Esteves, L.S.; Vital, H.; Dillenburg, S.R.; Patchineelam, A..; Addad, J. E. 2005. Praias arenosas e erosão costeira. In: Souza, C. R. G.; Suguio, K.; Oliveira, A. M. S. & Oliveira, P. E. (Eds.). Quaternário do Brasil. Ribeirão Preto: Holos, 130-152p. Suguio, K. 1973. Introdução à Sedimentologia. São Paulo, Edgard Blucher. Ed.da Universidade de São Paulo. 315p. Wentworth, C. K. 1922. A scale of grade and class terms for clastic sediments. Journal of Geology, 30: 377-392. ACKNOLEDGEMENTS The authors thank to Program of Post-graduation in Geography and Department of Geosciences of the Universidade Federal de Santa Catarina and Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq, by logistics support and academic of Oceanography Fernando Ribeiro, by sedimentological analyses. Journal of Coastal Research, Special Issue XX, 2011 1351
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