THE ROLE OF KELP DETRITUS IN THE GROWTH OF BENTHIC SUSPENSION FEEDERSIN AN UNDERSTORY KELP FOREST

Stands of understory kelps greatly alter the physical and biological e nvironment within the algal canopy. In some regions, kelps' can also c ontribute significantly to suspension feeder nutrition through detrita l pathways. In a field experiment utilizing artificial kelps, we attem pted to decouple and evaluate the physical versus nutritional mechanis ms by which understory kelps affect the growth rates of benthic suspen sion feeders. Suspension feeding organisms were translocated to patche s of real and artificial kelps at two subtidal sites, and growth rates measured. Physical parameters were not significantly different betwee n treatments (real versus artificial kelp), and thus any differences i n growth rate should be attributable to differences in detrital contri bution between real and plastic plants. Of six taxa of suspension feed ers examined, only one showed a significant treatment effect, and that species grew faster in the artificial kelp treatment. The difference between our result and those of previously published studies may relat e to issues of scale and species-specific plant secondary substances.