Size spectra of benthic biomass and metabolism

Logarithmic size spectra of animals from subtidal silty sand sediments of Helgoland Bight and Kiel Bay corresponded with the benthic size spectrum elaborated by Schwinghamer (1981).There was a meiofauna biomass peak in size classes from 0.05 to 0.5 pg organic carbon, a trough at about 5 pg, and a biomass increase per size class towards larger macrofauna size classes.Problems are identified regarding analysis of Foraminifera biomass and sampling of juvenile macrofauna (0.1 pg to 0.1 mg organic carbon), small macrofauna (0.1 to 10 mg) and large macrofauna.Mass-specific rates of oxygen consumption, as computed by Banse (1982), were used to construct, for the Helgoland Bight Station, a benthic size spectrum by metabolism.Logarithmic size classes in the range 0.05 to 0.5 pg organic carbon (meiofauna excluding Foraminifera) and in the range 5 pg to 1 g (macrofauna) each consumed about the same amount of oxygen: an equivalent of 0.6 to 1 m1 O2 h-', calculated per m*.For a general estimate, the size spectrum by metabolism may be a useful tool.