CAREER: Protist Nutritional Strategies in Permanently Stratified Antarctic Lakes

This project supported an integrated research and education program in the fields of polar biology and environmental microbiology, focusing on single-celled eukaryotes (protists) in high latitude ice-covered Antarctic lakes systems. Protists play important roles in energy flow and material cycling, and act as both primary producers (fixing inorganic carbon by photosynthesis) and consumers (preying on bacteria by phagotrophic digestion). The McMurdo Dry Valleys (MDV) located in Victoria Land, Antarctica, harbor microbial communities which are isolated in the unique aquatic ecosystem of perennially ice-capped lakes. The project studied: (1) the impact of permanent biogeochemical gradients on protist trophic strategy, (2) the effect of major abiotic drivers (light and nutrients) on the distribution of two key mixotrophic and photoautotrophic protist species, and (3) the effect of episodic nutrient pulses on mixotroph communities in high latitude (ultraoligotrophic) MDV lakes versus low latitude (eutrophic) watersheds.

Sampling dates: February 4 – April 10, 2008; November 11- 28, 2012; December 12, 2012

Sampling locations/depths:
East Lobe Lake Bonney/5m, 10m, 13m, 15m, 20m, 25m, 30m
West Lobe Lake Bonney/5m, 10m, 13m, 15m, 20m, 25m, 30m
Lake Fryxell/5m, 7m, 9m, 11m, 12m, 15m
Lake Vanda/10m, 20m, 30m, 40m, 50m, 60m, 70m, 75m, 80m

Two kinds of metadata from this project are available:

1) DNA sequence data – DNA was extracted from filtered lake water (1-2L) collected from sampling locations and dates reported above. Environmental DNA was PCR-amplified using primers specific for the following genes: 16S rRNA, 18S rRNA, rbcL, cbbM, nifJ, psbA. Genes were sequenced on an Applied Biosystems DNA analyzer or an Illumina MiSeq or HiSeq instruments. All DNA sequences from this project are available via GenBank.

2) Limnological metadata - Limnological data was collected from sampling locations and dates reported above. Data includes PAR, conductivity, temperature, Chlorophyll a, and macronutrients and is available via the McMurdo Dry Valleys LTER Data Center.