Immediate effects of a storm on coastal infauna

Abstract

Effects of storms on benthic infaunal communities have thus far been inferred rather than documented; especially lacking are studies examining immediate effects. To this end, the water column and 2 subtidal benthic sites were sampled before and after Storm David in September 1979. There were large post-storm increases in the numbers of infaunal species and individuals in the water column, presumably due to turbulent benthic boundary conditions. At the benthic stations, there were no pre vs. post-storm differences in the density of infauna; however, the number of species decreased at 1 station. There were storm-associated changes in the rank order of dominant infaunal taxa although these generally were rearrangements rather than substitutions. Cluster analysis of benthic data showed distinct spatial, but not temporal, groups. Because pre-and post-storm differences in benthic infaunal samples were not commensurate with the magnitude of change in the water column infauna, the storm apparently was more catastrophic to distant infaunal communities. Thus, we suggest that disturbance by storms may be a mechanism for wide post-larval dispersal of ostensibly obligate infauna.