Back to the future? Late Holocene marine food web structure in a warm climatic phase as a predictor of trophodynamics in a warmer South‐Western Atlantic Ocean

MYRIAN ÁLVAREZ; LUIS CARDONA; MARIA BAS; DAMIÁN G. VALES; IVAN BRIZ I GODINO; ENRIQUE A. CRESPO

GLOBAL CHANGE BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 25 p. 404 - 419

1354-1013

Stable carbon and nitrogen isotope ratios in the skeletal elements of both ancientand modern marine species from the Beagle Channel were used to compare thestructure of Late Holocene and modern food webs, and predict potential changes asa result of a Sea Surface Temperature (SST) increase in the region. Complementary,ancient and modern shells of limpets and mussels were isotopically analysed toexplore changes in the isotopic baseline and compare marine food webs throughtime after an appropriate correction for baseline shifts. Results confirmed a decliningpattern of marine primary productivity during the Late Holocene in the BeagleChannel. In general, the isotopic niches overlapped largely in the ancient food webin comparison to the current marine one, with the exception of that of cormorants(Phalacrocorax sp.). Our data suggest that all the species that have undergoneintense human exploitation (Arctocephalus australis, Otaria flavescens and Merlucciussp.) significantly increased their trophic levels. The most important finding of thiswork was the very high isotopic overlap between snoek (Thyrsites atun) and hake(Merluccius sp.) during the Late Holocene. Increasing SST as a result of global warmingcould favour the recolonization of the southern South‐Western Atlantic Ocean