Wilhelm, S. W. University of Tennessee, wilhelm@utk.edu
Smith, R. W. University of Waterloo, rsmith@sciborg.uwaterloo.ca

Although viruses are known to be pervasive components of aquatic environments, their ecology and influence on community structure remain understudied in the Great Lakes system. At stations occupied during August 1997 and July 1998 in the Western basin of Lake Erie, bacterial abundance in surface waters ranged from ca. 2 to 5 x 10^9 cells/L. During the same period viral abundance ranged from ca. 5 to 11 x 10^10 particles/L, providing virus-to-bacteria ratios (10 to 130) which are significantly higher than those reported for Lake Superior. Abundances were similar at stations in both the Central and Eastern basins of the Lake. Using standard conversion factors, thymidine estimates of bacterial carbon production ranged from 1 to 4 ug C/L/h in surface waters. The high viral and bacterial abundances provide for virus-host contact rates of ca. 6 to 11 contacts/cell/d. The frequency of visible infected cells in samples was 1.6 %, suggesting that ca. 11.2 % of the bacterioplankton may be infected. Burst sizes (determined by TEM) ranged from 8 to 22 visible phages per infected cell. These results suggest that viral infection may be a significant source of bacterial mortality as well as nutrient regeneration in Lake Erie.
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
Code: SS40TU0440S