Tietjen, T. E. University of Alabama, ttietjen@biology.as.ua.edu
Schlickeisen, E. E. University of Alabama, eschlick@biology.as.ua.edu
Groeger, A. W. Southwest Texas State University, ag11@swt.edu
Kelley, B. G. Southwest Texas State University,

 
LONGITUDINAL NUTRIENT LIMITATION OF PHYTOPLANKTON AND BACTERIA ALONG A RESERVOIR GRADIENT
 
Past studies on Canyon Reservoir, a deep water impoundment of the Guadalupe River (Texas, U.S.A.), have indicated that during the late summer of years with low inflow, algal nutrient limitation should shift from phosphorus limitation near the inflowing river to nitrogen limitation nearer the dam. During August of 1998, a year of low flow, a series of experiments were performed to assess changes in production and biomass accumulation of phytoplankton and bacteria in response to the addition of potentially limiting nutrients. Extremely low chlorophyll a concentrations were found over the entire length of the reservoir and stratification of the water column was evident at all sites. Preliminary results indicate no response in algal biomass accrual to the addition of potentially limiting nutrients at any point along the reservoir, while phosphorus limitation of primary production was prevalent at the sites nearer the river. In contrast, bacterial numbers increased in response to the addition of phosphorus at the 2 near river sites and to the addition of phosphorus and a metals mixture at the site nearest the dam. This experiment did not demonstrate the anticipated longitudinal pattern of algal nutrient limitation but did reveal similar responses by both phytoplankton and bacteria.
 
Day: Tuesday, Feb. 2
Time: 10:45 - 11:00am
Location: Sweeney Center
 
Code: SS19TU1045S