The distribution and ecology of Southern Elephant Seals and Adélie Penguins on the Holocene Ross Sea coast.

• Published in: Journal of Vertebrate Paleontology
• Main Authors: KOCH P., HALL B., NEWSOME S., BARONI, CARLO, SALVATORE, MARIA CRISTINA
• Other Authors: Koch, P., Hall, B., Baroni, Carlo, Newsome, S., Salvatore, MARIA CRISTINA
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2007
• Subjects: Adelie penguin; Southern Elephant Seal; ecology; climate change; Antarctica; Antarc*; Climate change; Elephant Seal; Elephant Seals; Macquarie Island; Mirounga leonina; Ross Sea; Southern Elephant Seals; Victoria Land
• Online Access: http://hdl.handle.net/11568/115669; https://doi.org/10.1080/02724634.2007.10010458; http://www.tandfonline.com/doi/abs/10.1080/02724634.2007.10010458#tabModule

Radiocarbon dates on skin hair and mummified carcasses show that southern elephant seals (SES; Mirounga leonina) occurred during the Holocene along the western coast of the Ross Sea (the Victoria Land Coast. VLC) from at least Edmonson Point (74°20' S) to Explorers Cove (77°30' S). The most recent occupation ended only 500 years ago. The closest breeding site to the region tod ay is Macquarie Island (54°30' S), 2500 km to the north. Most SES feed further north as well in the productive waters of the Subantarctic Front and Ant arctic Circumpolar Current (60-70° S). SES feed in open, ice-free water and they haul-out on ice-free beaches to molt and breed. They are largely absent from the VLC today because of abundant pack ice and land fast-ice. even in summer months. Thus the presence of abundant SES along the VLC suggests substantially less pack ice and fast-ice in the Ross Sea at intervals from the middle to late Holocene. This interpretation is supported by the distributions of relict Adelie penguin rookeries. These penguins nest on land but forage in pack ice. From 3800-23 00 yr BP penguins typically occur without SES (suggesting conditions similar to today) whereas from 2300-5 00 yr BP, SES occur but Adelie penguin rookeries are uncommon (indicating less ice than today ). From 620 0-3800 yr BP, SES and Adelie penguins co-occur at a number of sites along the VLC. suggesting intermediate conditions, with little fast ice but with nearby pack ice. Carbon and nitrogen isotope data from SES, other seals and Adelle penguins provision ally support the interpretation that Holocene SES did not forage in the Ross Sea but instead fed further north as they do today. In conclusion, a reduction in pack ice and fast-ice would have allowed SES to occupy VLC beaches. We are still assessing whether these sites were locations where SES went to molt , or if they represent breeding colonies entirely independent from those on subAntarctic islands to the north. These hypotheses are being tested with demographic data from mummies and ...