The McMurdo LTER lakes program is focused on understanding the environmental conditions and ecological processes of former and present lakes in the dry valleys. Our main objective is to provide general background information on the physical, chemical, and biological activity in Lakes Bonney (east and west lobes), Hoare, and Fryxell. Studies are being done to monitor lakes (and streams) in order to detect changes through time, and relate these to changes in physical parameters, e.g., climate, hydrology. Monitoring of the lakes and streams is also being done to collect data for water, major solute, and nutrient budgets of the lakes.

The non-turbulent nature of the perennially ice-covered lakes in the dry valleys restricts mixing of nutrients to diffusion processes. Pelagic lake investigations are being done to examine organic carbon transformations between phytoplankton and bacterioplankton, examine the influence of nutrient input via streams on phytoplankton productivity, and determine primary loss rates for the phytoplankton (e.g., respiration, sinking).

Lakes within the McMurdo Dry Valleys support abundant, widespread growths of benthic cyanobacteria-dominated mats. In a study of these mats in Lake Hoare during the 1994-95 field season, LTER scientists determined photosynthesis vs. photon flux curves, the absorption spectra of the mats, and biomass mats from a range of depths. Preliminary results show that the benthic mats are light-limited and that there is a decrease in mat biomass with depth in the lake.

Paleolimnological studies are being conducted to put present lake environments into historical perspective, tracing environmental changes (e.g., changes in lake productivity, chemistry, sedimentology, etc.) through recent time using lake bottom experiments. We aim to confirm and expand this record by using paleolake sediments left by lake stands (e.g., Glacial Lake Washburn), as well as investigate new dating techniques to refine temporal control.

Lake Locations, Measurement Sites