MEPS 128:247-259 (1995)  -  doi:10.3354/meps128247

Influence of epibenthos on meiobenthos of the Ceriops tagal mangrove sediment at Gazi Bay, Kenya

Schrijvers J, Okondo J, Steyaert M, Vincx M

A cage experiment was used to exclude the epibenthos from the Ceriops tagal mangrove sediment at Gazi Bay, Kenya. This made it possible to study interactions with the meiobenthos (in terms of predation, food competition and food enhancement). The density of the meiobenthic taxa and nematode genera and a broad range of abiotic variables were followed in a depth profile over 1 yr of caging. There was a significant exclusion effect in the upper sediment layer for total meiofauna, nematodes and oligochaetes during the first 2 mo and for copepods during the last 6 mo of caging. The density of the most common predatory and microalgae-feeding nematodes in particular tended to increase in the surface layers as well as the percentage of muddy detritus and pigment concentration. Food competition with the epibenthos seems to be most important in structuring the nematode community. This is suggested by the parallel exclusion effect on muddy detritus, pigments and nematode composition and the lack of evidence for upward nematode migration in the cage during the experiment. The same can be concluded for the oligochaetes, whereas copepod densities are believed to be controlled more by predation. These findings indicate that the meiofauna community of the C. tagal mangrove sediment (consisting of about 95% nematodes and oligochaetes) is part of a rather isolated, detrital food web with only minor predator-prey interactions with the epibenthos.

Nematodes . Meiobenthos . Epibenthos . Exclusion experiment . Mangroves . Kenya

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