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At a site in the Gulf of Mexico (29°54.6'N, 81°31.4'W) off the coast of northern Florida, harpacticoid copepod abundance is significantly enhanced around isolated "plants" (technically short shoots) of the seagrass Syringodium filiforme. Using inanimate mimics of seagrass short shoots, we demonstrate, in the field, that the enhanced abundance does not results from the presence of the plant as a living entity. Our experiments reveal a two-fold increase in bacterial biomass around both short shoots and mimics; the harpacticoids appear to be responding to a local increase in their resources. We suggest that the flow field around a short shoot improves the rate of supply of oxygen and other materials to sedimentary bacteria, thereby driving the effect. Given the ubiquity of structures that have similar flow effects, localized bacterial enhancement may be common and should be considered in studies of the effects of surface structures on soft-bottom community organization.

A method is described which allows an abundant taxon (Nematoda) to be subsampled while rarer taxa are completely sampled. A triply balanced F‐square design is used to choose a quarter of the sorting field for counting the nematodes. The technique showed no evidence of bias in estimating total numbers of nematodes, and a quarter subsample was accurate to within ±0.8% when there were > 200 nematodes in a sample. Estimates of the total number of nematodes in a sample were accurate to within ± 3.2% of their actual values. The technique gave subsamples of abundant nematode species which did not differ significantly from expectation.

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