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

TT Noji, CI-M Noji, K-G Barthel
1993 Marine Ecology Progress Series  
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 organlc carbon ranged in concentration from ca 1500 to 4000 and 70 to 270 pg I-', respectively, during the invest~gation. Concentrations of suspended chlorophyll a and pheopigments ranged from ca 0.03 to 0.20 and 0.2 to 0.9 pg I-', respectively. A decreasing tendency was observed over time for chlorophyll
more » ... ; this was presumably a result of reduced phytoplankton growth due to deteriorating light climate associated with the season. Sedimentat~on rates for total particulate material and POC ranged from 400 to 8000 and from 25 to 300 mg m-2 d-l, respectively. For chlorophyll a and pheopigments these rates were from 25 to 250 and 200 to 2000 pg m-' d.', respectively. The beginning and end of the study period were characterized by unusual features, which were attributed to processes of advection and resuspension of sediments. O n e 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 (< 0.14 % d-l) of suspended POC was respired by the mesozooplankton, whereas up to ca 5 % of suspended POC was exported via sedimentation. Further, best estimates indicate that ca 36 and 18 % of material sinking out of the upper 30 m and from the entire water column, respectively, were potentially respired by the benthos. Community respiration rates for the benthos were up to almost 1 order of magnitude greater than for the mesozooplankton. The nonrespired sedimented material presumably accumulates in the deeper parts of the fjord and may serve as a food source for enhanced benthic production in spring.
doi:10.3354/meps093089 fatcat:kzn57wgm3zf35dl5l5pniyphsq