Phytoplankton biomass and environmental factors over a gradient of clear to turbid peri-urban ponds

1. Small lakes and ponds with high nutrient loadings can be clear, turbid or intermediate, with low, high and intermediate phytoplankton biomass, respectively. 2. A combination of biotic and abiotic factors, such as hydraulic retention time, presence of submerged vegetation, depth, top-down phytoplankton control, and cascading effects of fish community structure, play an important role in phytoplankton biomass control when nutrients are not limiting. Different combinations of these factors lead to different levels of phytoplankton biomass. 3. Identification of the main factors controlling phytoplankton biomass in a particular pond or a small lake is essential for choosing an appropriate management strategy for the maintenance of a desired ecosystem state. 4. When a pond or a small lake ecosystem is impaired by eutrophication, a considerable degree of its ecological quality can be restored through the modification of some environmental factors when a sufficient reduction in nutrient input is not feasible. Copyright (c) 2006 John Wiley & Sons, Ltd.