Helen C Schlimm

Abstract

​

Recent research documents climate-induced changes in the algal communities of West Greenland lakes; however, less is known about the response of zooplankton to climate change effects in this region. Zooplankton are predominantly the top predator in these lakes, and thus may be changing due to direct climate effects on physical lake habitat and chemistry or indirect effects on their food source. Cladoceran remains from two lake sediment cores were collected in the Kangerlussuaq region of southwest Greenland: SS1341, located midway between the Greenland ice sheet and the coast, and SS901, close in proximity to the ice sheet. Modern zooplankton data were analyzed from a suite of 26 lakes across both regions and utilized neo- and paleolimnological methods to characterize shifts in zooplankton communities. 

​

Paleolimnological results suggest a shift to increased dominance of a particular pelagic genus, Bosmina, over the benthic genus Chydorus in modern times. This trend differs from an established long-term record of zooplankton change from another lake in this region that observed a modern decline in pelagic genera, suggesting variability among systems in zooplankton community response to climate change. Similar variability within paleolimnological records in this region has been observed for small centric diatom species. Modern analysis yielded a correlation of Bosmina and Eubosmina spp. distribution to increased lake clarity and reduced algal biomass, suggesting the effects of climate change may be mediated by bottom-up food web mechanisms. By pairing modern and paleoecological approaches, we are better able to understand the mechanisms driving long-term shifts in plankton communities in these Arctic lakes.

​