| Autor: |
De María, Maite1 (AUTHOR) maitedmm@gmail.com, Szteren, Diana1 (AUTHOR) diana@fcien.edu.uy, García-Alonso, Javier2 (AUTHOR) jgalonso@cure.edu.uy, de Rezende, Carlos E.3 (AUTHOR) crezende@uenf.br, Araújo Gonçalves, Rodrigo4 (AUTHOR) rodrigoag@puc-rio.br, Godoy, José Marcus4 (AUTHOR) jmgodoy@puc-rio.br, Barboza, Francisco R.5 (AUTHOR) fbarboza@geomar.de |
| Abstrakt: |
Marine mammals and the ecological functions they provide to coastal and pelagic ecosystems are increasingly threatened by the intensification of anthropogenic impacts. The Uruguayan coastline throughout the 20th century, like other coastal environments worldwide, has been the sink of a variety of trace metals derived from the rapid urbanization and industrialization of related land areas. This coastline is inhabited by two species of pinnipeds trophically and spatially segregated. Otaria byronia feeds in coastal environments while Arctocephalus australis preys mainly offshore. The present study aimed to analyze historic changes in concentrations of trace elements in teeth of both species from 1941 to the present day. We analyzed the dentin of 94 canine teeth using stable isotope analysis (δ13C) and ICP-MS to determine their feeding areas and the concentration of 10 trace elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) respectively. The concentration of Cr was significantly higher during '70–'80s, in both species coinciding with tannery industry development. Both species of pinnipeds have been differentially exposed to trace elements depending on their feeding area. A pelagic diet, possibly based on squid, increased the concentration of Cd in A. australis , while O. byronia has been more exposed to anthropogenic Pb and Cu associated to a costal and more benthic diet. Our results highlight dentin as a reliable matrix for historic studies on the exposure to trace elements. In light of our results, the O. byronia 's declining population could be the result of the synergistic effects of trace elements together with other ecological pressures faced in their environment. Spatial trophic segregation determines differential exposure to trace elements in two species of pinnipeds. Arctocephalus australis was more exposed to cadmium due to their offshore pelagic diet (based on squid), while Otaria byronia has been more exposed to lead and cooper associated to their coastal and benthic diet during the 20th century. Both species showed an increase of chromium exposure in the '70–'80s that coincides with the development of the tannery industry in the area. Unlabelled Image • 70-year analysis of exposure to trace elements in two pinniped species. • Both species had a higher concentration of Cr during '70–'80s, related to industry development. • O. byronia with a costal-benthic diet had higher exposure to Pb and Cu • A. australis have been more exposed to Cd, associated to their pelagic diet. • Dentin is a reliable matrix to analyze trace element concentration in pinnipeds. [ABSTRACT FROM AUTHOR] |
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