Isotope (δ18O- δ13C) signatures of Mollusk shells as proxies of marine environmental scenarios, part of South East Coast of India
| Autor: | Nadimikeri, Jayaraju, Ballari, Lakshmanna, Ganugapenta, Sreenivasulu, Madakka@gmail.com, Mekapogu, Bona, Praveena |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| Popis: | In the tropical to subtropical marine ecosystems, we carried out stable isotope analyses (δ18O- δ13C) on 5 serially-sampled modernMollusk shellscollected from coastal sediments in parts of East Coast of India. Certainphysico-chemical parameters viz., pH, Temperature, EC, Salinity, Dissolved oxygen( DO) and Organic matter (OM) were recorded . Shell samples reveal variations in temperature and/or seawater δ18O in their δ18O profiles. Unusually high or low δ18O values measure the intensity of seasonal upwelling or freshwater input, respectively. To quantify marine environment, baseline δ18O values have been calculated from average temperatures. Analyses of stable oxygen isotopes from Mollusk shells (Venus clam shells) indicate a significant change in sea surface temperatures (SST; 20C) .Baseline-normalized δ18O profiles reveal little or no fresh freshwater input in study area. The shell δ18O range (Δ18O) and δ18O-δ13C (O-C) were integrated for correlation to further identify marine environments and thus nutrient source and status.Eutrophicenvironments are characterized by high Δ18O and low O-C correlation. In contrast, theoligotrophicenvironments are low to moderate Δ18O and non-significant to positive O-C correlation. It is believed that application of these studies to fossil Mollusk shells, can characterize the nutrient status of ancient ecosystems. This work is considered to be first report of molluscan shells from marine environments of Indian coasts The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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