October 31, 2014

Student Research Highlight: Microbial Communities in Antarctica

Catherine Luria is finishing her second year in the Brown-MBL Graduate Program, advised by Hugh Ducklow (Ecosystems Center, MBL) and Jeremy Rich (Dept. of Ecology and Evolutionary Biology, Brown University). She recently returned from her first field season on the Antarctic Peninsula, where she participated in the Palmer Station Long Term Ecological Research (LTER) Project.

The peninsular region is one of the most rapidly warming regions on earth, with a 4-6°C increase in midwinter temperatures over the last 50 years and a 40% decline in winter sea ice extent. These changes are having profound impacts on all levels of the ecosystem, from marine diatoms to Adelie penguins.

Catherine is examining not only how microbial communities in this region change across study sites, seasons, and years, but also what factors drive microbial seasonal succession against a backdrop of rapid climate change. She is particularly interested in the effects of annual sea ice advance and retreat on microbial communities. As sea ice forms during the austral fall, bacteria and phytoplankton are entrained in the ice and often persist through the winter. In the spring, the sea ice melts releasing organic matter as well as bacteria and phytoplankton. This water column “seeding” may have dramatic impacts on microbial community composition within the water column and trigger phytoplankton blooms that help support this productive ecosystem. Although previous studies have examined the effects of sea ice extent and duration on primary production, zooplankton, and seabirds, little is known about the impact of sea ice advance and retreat on microbes and how microbes will respond to climate-driven declines in sea ice extent and duration. Catherine is exploring this question through a combination of environmental sampling and incubation experiments. She is excited to return to the Antarctic in September 2012 for further research.

 by Catherine Luria, May 2012