Inferring centennial terrigenous input for Patos Lagoon, Brazil: the world's largest choked coastal lagoon
| Autor: | Laura Fornaro, Michel Doeppre Ivanoff, Carolina Bueno, Felipe García-Rodríguez, Rubens Cesar Lopes Figueira, Elírio E. Toldo, Paulo Alves de Lima Ferreira |
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| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
010506 paleontology Terrigenous sediment 010604 marine biology & hydrobiology Sediment Weathering Aquatic Science 01 natural sciences Deposition (geology) chemistry.chemical_compound Oceanography chemistry Carbonate Environmental science Sedimentary rock Precipitation Sedimentology 0105 earth and related environmental sciences Earth-Surface Processes OCEANOGRAFIA |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | This study introduces and discusses inorganic geochemical data from Patos Lagoon, the world’s largest choked coastal lagoon located in southern Brazil. Here, we characterise the sedimentary geochemical environment using different elemental ratios to assess the influence of both anthropogenic activities and the natural hydrological regime on the contemporary geochemical record. Three sediment cores collected in the freshwater domain of Patos Lagoon were analysed. Elements Al, Ca, Cr, Fe, K, Sr, Ti and V were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Strong correlations between Sr and Ca, together with the lack of correlation with detrital elements suggested that carbonate precipitation is particularly important in this system. Lithogenic elements Al, K, Fe and Ti reflected the influence of the Guaiba River on the sedimentary sequences of Patos Lagoon. The K/Al ratio was used to investigate changes in weathering patterns and Ti/Al to evaluate grain size changes. Ti/Ca provided an excellent proxy for inferring historical changes in wetter and drier conditions, and also appears to be sensitive to the influence of ENSO events. Finally, the V/Cr ratio reflected the prevailing reducing conditions of the bottom sediments. Overall, our findings show that processes of sediment weathering, transport and deposition are mostly related to natural process, and given the large size of the system, the dilution processes could play an important role in attenuating geochemical changes related to human impacts. |
| Databáze: | OpenAIRE |
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