CESIMAR - CENPAT   25625
CENTRO PARA EL ESTUDIO DE SISTEMAS MARINOS
Unidad Ejecutora - UE
artículos
Título:
Holocene changes in the trophic ecology of an apex marine predator in the South Atlantic Ocean
Autor/es:
ZANGRANDO, A.J.F.; CARDONA, L.; VALES, DAMIÁN A. ; BORELLA, F.; ZANGRANDO, A.J.F.; CARDONA, L.; VALES, DAMIÁN A. ; BORELLA, F.
Revista:
OECOLOGIA
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2016 p. 555 - 570
ISSN:
0029-8549
Resumen:
Stable nitrogen and carbon isotopes from bone collagen were used to reconstruct the foraging ecology of South American fur seals (Arctocephalus australis) since the Middle Holocene in the southwestern South Atlantic Ocean. Zooarchaeological and modern mollusc shells were also isotopically analysed to account for changes in the ecosystem baseline throughout time. Fur seals inhabiting the Río de la Plata (35º S, 57º W) and surrounding areas 7000 years ago were depleted in 13C as compared with their modern counterparts (-15.9 ± 0.6 ? vs. -13.5 ± 0.8 ?) but differences in δ15N were not significant (21.3 ± 1.9 ? vs. 20.5 ± 0.6 ?). Conversely, fur seals from northern and central Patagonia seem not to have changed diet from 2200-1000 BP to present (δ13C: -13.2 ± 0.5 ? vs. -13.5 ± 0.5 ?, δ15N: 21.1 ± 1.8 ? vs. 20.6 ± 1.0 ?) and the same was true for fur seals from Tierra del Fuego between 6400-2600 BP (average period δ13C: -15.2 ± 0.9 ? and δ15N: 20.4 ± 0.6 ?). In contrast, isotopic ratios dropped in fur seals from Tierra del Fuego during the 19th century (δ13C: -17.2 ± 0.3 ?, δ15N: 18.6 ± 0.7 ?), coinciding with the decimation of the local population by sealers and a major drop in marine primary productivity. Currently, fur seals from Tierra del Fuego forage at a lower trophic level than during most of the second half of the Holocene (δ13C: -13.2 ± 0.7 ?, δ15N: 19.0 ± 1.6 ?).