What difference does a century make? Shifts in the ecosystem structure of the Ross Sea, Antarctica, as evidenced from a sentinel species, the Weddell seal

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Hückstädt, Luis A., McCarthy, Matthew D., Koch, Paul L., Costa, Daniel P.
• Other Authors: E&P Sound and Marine Life Joint Industry Project of the IAGOP, Division of Polar Programs, Marine Conservation Institute - Mia G. Tegner Grants in Historical Ecology
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2017
• Subjects: General Agricultural and Biological Sciences; General Environmental Science; General Immunology and Microbiology; General Biochemistry, Genetics and Molecular Biology; General Medicine; Antarc*; Antarctica; Ross Sea; Weddell Seal; Weddell Seals
• Online Access: http://dx.doi.org/10.1098/rspb.2017.0927; https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2017.0927; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2017.0927

The arrival of humans to Antarctica's Ross Sea (100+ years ago) led to a slow, but sustained increase in human activities in the area. To investigate if human presence has influenced the structure of the ecosystem over the last century, we compared historical ( ca 100 years old) and modern samples of a sentinel species, the Weddell seal ( Leptonychotes weddellii ), using both bulk tissue and compound-specific stable isotope analysis. The historical isotopic niche of Weddell seals was over five times larger than the modern niche. The isotopic values of individual amino acids showed a clear segregation between historical and modern samples, indicative of differences at the base of the trophic web. Further, we found no significant differences in the trophic position of Weddell seals between the two periods. Our study revealed that the Ross Sea has undergone detectable changes (i.e. in the primary producers community) in the last century, but the presence of humans has not disrupted trophic interactions supporting Weddell seals.