McKnight, D. INSTAAR, University of Colorado, mcknight@snobear.colorado.edu
Tate, C. U. S. Geologial Survey, cmtate@usgs.gov
Niyogi, D. University of Colorado, INSTAAR, niyogi@colroado.edu

 
CRYPTOBIOTIC PRESERVATION OF CYANOBACTERIAL MAT IN GLACIAL MELTWATER STREAMS IN THE MCMURDO DRY VALLEYS
 
Cyanobacterial mats are common in glacial meltwater streams of the McMurdo Dry Valleys in Antarctica. These mats are perennial, growing during the summer flow period and overwintering in a freeze-dried state. The streams flow through a barren landscape of unconsolidated alluvium and are a major linkage between the glaciers and the lakes in the valley floors. The cyanobacterial mats are effective in assimilating nutrients and regulate nutrient fluxes to the lakes. One persistent feature which promotes growth of the mats is the formation of a stone pavement in the streambed from long term freezing and thawing of the hyporheic zone. We conducted an experiment in which meltwater was routed to a relict channel which had not had sustained flow since 1969. We discovered that there were relict algal mats in the channel which rapidly grew within a few days of the arrival of flow. Within two weeks a full microbial ecosystem was active over the 1.5 km stream reach. This experiment shows that because of the stability of the stone pavement habitat microbial stream ecosystems can persist in a cryptobiotic state for long periods and respond rapidly to renewed flow.
 
Day: Tuesday, Feb. 2
Time: 02:00 - 02:15pm
Location: Sweeney Center
 
Code: SS27TU0200S