Brooks, B. W. The University of Mississippi, bbrooks@olemiss.edu
Threlkeld, S. W. The University of Mississippi, stt@olemiss.edu

 
EFFECTS OF NUTRIENTS, PISCIVORES, AND A MIXTURE OF BENTHIVORES, OMNIVORES AND ZOOPLANKTIVORES ON THERMAL PROFILES OF EXPERIMENTAL PONDS
 
Zooplanktivorous fish may influence water temperature and mixing depth by reducing zooplankton, and increasing phytoplankton and light attenuation. An experimental test of this hypothesis was conducted in 29 ponds at The University of Mississippi's Field Station during summer 1997. Piscivores, nutrients, and a mixture of three non-piscivorous consumer fish (benthivores, omnivores and zooplanktivores) were assigned to ponds according to a cross-classified 2^3 factorial mixture design. Thermal profiles and water quality endpoints were assessed weekly while water and air temperature and PAR were measured continuously. Surface temperatures of all ponds closely tracked air temperature and PAR. Consumer fish affected particulate organic matter, transparency, bottom temperature and water column stability. Benthivore-dominated mixture treatments enhanced turbidity, particle abundance and phytoplankton and decreased Secchi depth. Zooplanktivore-dominated mixture treatments did not enhance phytoplankton but increased extinction coefficient and water column stability. Resolution of temperature measurements was important in detection of treatment effects because non-piscivorous consumer fish treatments increased weekly bottom temperature measurements by about 1^oC while length of continuous stratification was increased by zooplanktivore-dominated treatments.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS04TH0998S