Fertilization of Earth Ponds. II: Effects on Plankton Communities

Abstract

A study of the effects of slurry inorganic and organic of fertilizers on the production of phyto-and zooplankton in earth ponds was conducted in Central Scotland, U.K. over a period of one year. For the inorganic fertilization, replicate ponds were treated with low and high phosphorus (LP, HP), high phosphorus and nitrogen (HPN); while the organic fertilization replicated treatments were low and high chicken (LC, HC) manure and combination of high chicken and cow (HCC) manure. Each of the fertilization programmes had two untreated controls (CTRL), without fertilizer. All the Cyanophyceae (blue-green algae) than the CTRL, but HPN, produced vastly more algae that the others. The response pattern of Dinophyceae (dinoflagellates) was low. The organic trials responded to treatments, but more positively to HC and HCC in the zooplankton, and dominant genera encountered in both trials were Cladocera, Rotifera and Copepoda. The role of decaying plankton and organic manure as sources of detritus and carbon, providing nutrients in a vicious circle for optimum biological production is discussed in the light of food web sustainability in semi-intensive and intensive aquaculture systems.

Journal of Aquatic Sciences Volume 14, April 1999, pp. 13-18




KEY WORDS:

Fertilization, earth pond, phytoplankton, zooplankton and detritus.