LONG-TERM TIME SERIES OF SENTINEL PHYTOPLANKTON IN THE MCMURDO DRY VALLEY LAKES, ANTARCTICA

High-latitude meromictic lakes such as those in the Antarctic McMurdo Dry Valleys (MDV) harbor aquatic ecosystems dominated by the microbial loop. Within this habitat, which is limited year-round by light and nutrients, protists, or single celled eukaryotes, play outsized roles in the food web as the dominant primary producers and the apex predators. Thus, the MDV lake ecosystem represents an ideal system to study the role of sentinel protist taxa in carbon and nutrient cycling. The perennially ice-covered lakes are part of the McMurdo Long Term Ecological Research (McM LTER; mcmlter.org) which curates a three decade dataset of physicochemical and biological parameters. This talk will highlight the biogeography and trophic roles of sentinel protist taxa of MDV lakes. Two decades of data will be synthesized from generated from a chlorophyll a spectral fluorometer (the bbe FluoroProbe), representing annual and long-term trends of three key phytoplankton: an obligate photoautotroph (chlorophytes), and two mixotrophs (haptophytes and cryptophytes). Year-round monitoring has revealed that chlorophytes dominate the summer populations, while mixotrophs are abundant and active during the long, dark polar winter. On the other hand, long-term trends suggest that chlorophytes may be outcompeting other phytoplankton taxa. These changes could have significant impacts on the MDV lake food web.

Primary Presenter: Rachael Morgan-Kiss, Miami Univeristy (morganr2@miamioh.edu)

Authors:

Rachael Morgan-Kiss, Miami University  (morganr2@miamioh.edu)

Rachel Seddon, University of New Mexico  (rhennegan@unm.edu)

Jade Lawrence, University of New Mexico  (jlawrence1@unm.edu)

Rochelle Pereira, Miami University  (pereirrp@miamioh.edu)

Bradley Krzysiak, Miami University  (krzysibm@miamioh.edu)

Cristina Takacs-Vesbach, University of New Mexico  (cvesbach@umn.edu)