Pelagic-benthic coupling during the onset of winter in a northern Norwegian fjord. Carbon flow and fate of suspended particulate matter

The distribution of suspended material and sedimentation were investigated in a northern Norwegian fjord for 4 wk during the onset of winter in 1989. Total suspended particles and particulate organic carbon ranged in concentration from ca 1500 to 4000 and 70 to 270 μg l−1, respectively, during the investigation. Concentrations of suspended chlorophyll a and pheopigments ranged from ca 0.03 to 0.20 and 0.2 to 0.9 μg l−1, respectively. A decreasing tendency was observed over time for chlorophyll a; this was presumable a result of reduced phytoplankton growth due to deteriorating light climate associated with the season. Sedimentation rates for total particulate material and POC ranged from 400 to 8000 and from 25 to 300 mg m−2 d−1, respectively. For chlorophyll a and pheopigments these rates were from 25 to 250 and 200 to 2000 μg m−2 d−1, respectively. The beginning and end of the study period were characterized by unusual features, which were attributed to processes of advection and resupension of sediments. One consequence of these hydrographic processes is a focusing of sediments to deeper parts of the fjord. A carbon budget showed that only a small fraction (