Finelli, C. M. Academy of Natural Sciences, finelli@acnatsci.org
Hart, D. M. Academy of Natural Sciences, hart@acnatsci.org

 
SEPARATING THE ECOLOGICAL EFFECTS OF MEAN FLOW SPEED FROM TURBULENCE INTENSITY: AN EXPERIMENTAL APPROACH
 
Turbulent flow is an important environmental feature in many freshwater and marine ecosystems. Yet the effects of turbulence on biological processes may be difficult to separate from the effects of mean flow, especially because these two flow components are often highly correlated. We used a 2 x 2 factorial design to study the effects of mean flow vs. turbulence on the ingestion rates of suspension-feeding stream insects. In a laboratory flume, we measured the feeding rates of larval black flies exposed to four flow treatments (2 levels of flow speed X 2 levels of rms-turbulence intensity). Ingestion rates were significantly higher at the low flow speed, when adjusted for turbulence effects. In contrast, turbulence had no effect on ingestion rates. This type of experimental approach is needed to develop a more complete understanding of the direct and indirect effects of flow on aquatic organisms.
 
Day: Wednesday, Feb. 3
Time: 10:30 - 10:45am
Location: Eldorado Hotel
 
Code: SS03WE1030E