Meeting Abstract

P1.34  Sunday, Jan. 4  Ecology of injury in marine soft sediment communities: methyl green staining improves identification of regenerating spionid polychaetes LINDSAY, S.M.; Univ. of Maine, Orono slindsay@maine.edu

Marine infauna such as polychaetes are ecosystem engineers, disturbing sediments as they feed, defecate, burrow, irrigate and build tubes. These activities influence fluxes between sediments and the water column, recruitment and competitive interactions. Factors that change infaunal activity can thus impact sediment biogeochemistry and benthic communities. Infauna commonly experience non-lethal loss of body tissue and such injury has direct and indirect effects on infauna and ecological interactions in marine sedimentary habitats. Predicting the degree to which injury impacts soft-sediment communities requires accurate estimates of infaunal injury rates. Because soft-bodied infauna do not have visible scars after they have regenerated, knowing whether a seemingly intact individual may have experienced injury is difficult. For polychaetes, most estimates of injury rates in the field have been conservative, only counting worms that have obviously regenerating body parts. In addition, field surveys of injury have tended to be snap-shots, taken at one site over only short periods of time. Rapid regeneration in some species can mask injury, especially if sampling intervals are long. This study evaluated a histological stain, methyl green (MG), as a method to improve identification of recently injured but apparently intact spionid polychaetes. Visual and MG methods for identifying regenerating worms were compared in several species of spionid polychaetes collected from False Bay, WA and Lowes Cove, ME. Traditional visual inspection underestimated the frequency of injury/regeneration by approximately 5-20% depending on the species. The utility and limitations of MG staining as an assay for infaunal injury will be discussed.