Publication Abstract

Sensitivity of a benthic, metazoan,biomass size spectrum to differences in sediment granulometry

D.E Duplisea and A. Drgas

Benthicbiomass size spectra of meiofauna and macrofauna (BBSS) were examined at 4 sites in theAsko area, on the Swedish coast of the northern Baltic Sea proper. The sites ranged inmedian sediment grain size from a coarse sand (680 µm) to mud (< 63 µm). Previousempirical work and theory suggests that BBSS are bimodal where sediment granulometrypermits the existence of both fauna that live interstitially and those that burrow; eachbiomass mode reflects constraints on organism body size for each activity. Two hypothesesbased on this theory are tested here: (1) BBSS are bimodal in sediments which support bothan interstitial and burrowing fauna and (2) the biomass trough between modes of thespectrum changes consistently with sediment grain size. None of the BBSS from any of thesites were bimodal; thus, the first hypothesis was rejected. Shapes of spectra variedsomewhat among sites but showed no consistent difference related to sediment granulometry;thus, the second hypothesis was rejected. To further test these hypotheses, spectra wereconfined to infauna by removing the surface sediment layer (0 to 1 cm), thereby removingepibenthic fauna. Both hypotheses were once again rejected when the spectra consisted ofonly infauna.

Reference:

D.E Duplisea and A. Drgas, 1999. Sensitivity of a benthic, metazoan, biomass size spectrumto differences in sediment granulometry. Marine Ecology Progress Series, 177: 73-81.