BENTHIC-PELAGIC COUPLING IN THE GREENLAND NORWEGIAN SEA AND ITS EFFECT ON THE GEOLOGICAL RECORD

The sedimentation pattern of organic material in the Greenland-Nonvegi an Sea is reflected in the surface sediments, although less than 0.5% of the organic matter is buried in the sediment. Maximum fluxes and be nthic responses are observed during June and/or August/September, foll owing the pattern of export production in the pelagial zone. The annua l remineralization rate on the Voring Plateau is 3.0 g C m(-2) a(-1). Freshly settled phytodetritus, as detected by chlorophyll measurements , is rapidly mixed into the sediment and decomposed. It stimulates the activity of benthic organisms, especially foraminifera. The mixing co efficient for this material is D-b = 0.2 cm(2) d(-1), which is two to three orders of magnitude higher than that estimated from radiotracer methods. The effect on the geological record, however, is likely to be small. Chlorophyll-containing particles are at first very evenly dist ributed on the seafloor. After partial decomposition and resuspension, a secondary redistribution of particles occurs which can result in th e formation of a high accumulation area, with an up to 80-fold increas e in the sedimentation rate by lateral advection. This is mainly due t o physical processes, because biodeposition mediated by benthic animal s increases sedimentation by only a factor of two or three.