Reconstructing ancient and modern food webs of Antarctic krill predators

Gentoo penguins rearing young in Antarctica. (Photo: Michael Polito)

Gentoo penguins rearing young in Antarctica. (Photo: Michael Polito)

The Southern Ocean is undergoing rapid change due to the coupled effects of ongoing global climate change and the impacts of recent and historical anthropogenic exploitation. This project looks to investigate the underlying mechanisms behind shifts in the diets and paleohistory of Antarctic krill predators, which act as sensitive indicators of climate variability and anthropogenic disturbance. This research will help place recent ecological changes in the Southern Ocean into a larger historical context by examining proposed decadal and millennial-scale variation in predator trophic dynamics, population expansion and contraction, and large-scale shifts in the Antarctic marine food web. This research will also refine the use of compound-specific stable isotope analysis of amino acids as a paleoecological tool novel to studies in Antarctica. This project will take place in the Antarctic Peninsula and Ross Sea regions using modern and ancient Antarctic krill predator (penguins, seals, and squid) tissues from paleoecological excavations as well as historic museum specimens. This research will be completed in collaboration with scientists from Argentina, Canada, China, Italy, New Zealand, and the United Kingdom.

Primary Collaborators: Dr. Michael Polito (Louisiana State University); Dr. Steven Emslie (UNC Wilmington)

Publications:

McMahon KW, Polito MJ, Abel S, McCarthy MD, Thorrold SR (2015) Carbon and nitrogen isotope fractionation of amino acids in an avian marine predator, the gentoo penguin (Pygoscelis papua). Ecology and Evolution 5:1278-1290 doi:10.1002/ece3.1437

A schematic diagram of ecosystem perturbations in the Antarctic Peninsula over the past 200 years (from Trivelpiece et al. 2011).

A schematic diagram of ecosystem perturbations in the Antarctic Peninsula over the past 200 years (from Trivelpiece et al. 2011).

Climate trends, penguin occupation history (solid bars) and dietary trends proposed from previous studies (Polito et al. 2002; Hall et al. 2006, Emslie et al. 2007, Lorenzini et al. 2009, 2010). Samples collected during this study will be used to test penguin population and dietary shifts in response to Holocene-scale climatic warming and cooling trends.

Climate trends, penguin occupation history (solid bars) and dietary trends proposed from previous studies (Polito et al. 2002; Hall et al. 2006, Emslie et al. 2007, Lorenzini et al. 2009, 2010). Samples collected during this study will be used to test penguin population and dietary shifts in response to Holocene-scale climatic warming and cooling trends.

 

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