MEPS 177:73-81 (1999)  -  doi:10.3354/meps177073

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

Daniel E. Duplisea1,*, Aleksander Drgas2

1Department of Systems Ecology, Stockholm University, S-10691 Stockholm, Sweden
2Department of Oceanography, Sea Fisheries Institute, Kollataja 1, PL-81-332 Gdynia, Poland
*Present address: Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, United Kingdom. E-mail:

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

KEY WORDS: Community structure · Grain size · Size distribution · Invertebrate · Meiofauna · Macrofauna

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