Bukaveckas, P. A. University of Louisville,
Koch, R. University of Louisville,
Sellers, T. University of Louisville,
Shostell, J. University of Louisville,
Williams, J. University of Louisville,
NUTRIENT LIMITATION OF PHYTOPLANKTON GROWTH IN ADVECTIVE ENVIRONMENTS: IMPLICATIONS FOR DOWNSTREAM FLUXES OF N, P, AND SI.
Phytoplankton have been studied extensively in lentic fresh waters, yet comparatively little research has focused on factors regulating their production in advective environments (estuaries, rivers, reservoirs). Advective environments are characterized by downstream directionality of water flow or, in the case of estuaries, by tidal-influenced bidirectional flow. In these systems, advective losses may be more important than density-dependent factors such as nutrient limitation in determining net production. Furthermore, the suspended particulate load carried in flowing waters reduces light penetration and may prevent utilization of available nutrients. During low-flow periods in 1997 and 1998 we conducted dilution assays to quantify phytoplankton growth rates under ambient and nutrient-enriched conditions. We hypothesized that the severity of nutrient limitation would progress along an advective gradient represented by three sites of varying water residence time (WRT). The three sites included an impoundment of a medium-size river (longest WRT), an impoundment of a large river (Kentucky Lake) and a reach of the Ohio River (shortest WRT). Our results suggest that nutrient limitation is common despite constraints imposed by light availability and advective loss. We observed a progression from weak P limitation in early summer to strong N limitation in late summer.
Day: Monday, Feb. 1
Time: 04:15 - 04:30pm
Location: Hilton of Santa Fe