The effects of organic enrichment upon a community of meiobenthic harpacticoid copepods

A nutrient enrichment experiment was conducted on an estuarine intertidal beach. A nutrient suitable for marine heterotrophic bacteria, derived from acid-hydrolysed casein, was applied to areas of sediment at low tide, at two frequencies. At the greater frequency of application the numbers of species of harpacticoid copepod comprising the community increased, as did the logarithmic series index of diversity. Displacement, presumably competitive, of the numerically dominant species by two confamilial species, formerly of less abundance, occurred and resulted in a decrease in the Berger-Parker dominance diversity. As the community converged to an equilibrium, due to the rapid growth rates of two species, it was predicted that the species richness and ecological diversity of the community would decrease, as some species underwent competitive exclusion, and in so doing would raise the dominance diversity. Before harpacticoid copepod communities can be used satisfactorily in biological monitoring programmes more basic research is needed to assess the response of a variety of meiobenthic communities to various loads of organic pollution.