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The Effects of Complex Trophic Interactions on a Marine Microbenthic Community
Author(s) -
Walters Keith,
Moriarty D. J. W.
Publication year - 1993
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1940076
Subject(s) - meiobenthos , trophic level , intertidal zone , seagrass , ecology , biomass (ecology) , benthic zone , biology , microbial loop , community structure , food web , bioturbation , sediment , environmental science , oceanography , ecosystem , paleontology , geology
The consequences of complex trophic interactions for the dynamics of a natural microbenthic community from an intertidal Australian seagrass bed were examined during experiments in January, March, April, and June 1989. Effects of meiofauna and protist density manipulations on bacterial numbers and division rates and microalgal biomass were determined over 6 d each months. Results varied among experiments, microbial groups, and vertical positions within the sediment. Meiofaunal effects increased bacterial division rates but not densities in January subsurface and March surface sediments. In June, enhanced meiofaunal densities decreased subsurface but increased surface bacterial densities. A complex, tri—trophic—level interaction among meiofauna, protists, and bacteria probably caused the increased bacterial densities in June surface sediments. Meiofauna had no discernible effect on bacterial densities and division rates in January surface and March subsurface sediments even though relatively small (<50%) differences between treatments could be detected with reasonable statistical power. Changes in microalgal biomass could not be attributed to experimental treatments, and meiofauna likely have a limited effect on microalgae in this intertidal seagrass habitat. Results indicate that the combined effects of meiofauna can alter microbial densities and growth rates and significantly affect microbenthic community structure. Spatial and temporal variability in the nature of trophic interactions will determine the cumulative effects of meiofauna on microbial communities.