Benthic energy flow during a simulated autumn bloom sedimentation

Sedimentation of an autumn &atom bloom and its effect on sediment was simulated in the laboratory. Benthic response was similar to that observed in previous field studies: (1) a response within hours, (2) a rise of the chemocline, and (3) a change to pronounced anaerobiosis. Benthic metabolism was affected down to at least 7 cm sediment depth. Significantly more organic matter was consunled than was added by &atoms. Sediment oxygen consumption explained < 3 O/ O of the organic matter used, while heat production explained 89 % of the burned material integrated over 7 cm sediment depth. The geochernical model of oxidizing organic matter is criticized Development of ATP-blomass was in phase with the observed pattern of heat production. Efficiency of benthic response (P/C) was 50 to 60 % in the surface and