Pelagic turnover and transport to the bottom of particulate organic material in the northern Øresund
Nicolaisen, W.; Christensen, H. (1986). Pelagic turnover and transport to the bottom of particulate organic material in the northern Øresund, in: Muus, K. (Ed.) Proceedings of the 20th European Marine Biology Symposium: Nutrient Cycling. Processes in Marine Sediments, Hirtshals, Denmark, 9-13 September 1985. Ophelia: International Journal of Marine Biology, 26: pp. 317-332 In: Muus, K. (Ed.) (1986). Proceedings of the 20th European Marine Biology Symposium: Nutrient Cycling. Processes in Marine Sediments, Hirtshals, Denmark, 9-13 September 1985. European Marine Biology Symposia, 20. Ophelia: International Journal of Marine Biology, 26. ISBN 87-981066-4-3. 477 pp., more In: European Marine Biology Symposia., more |
| Authors | | Top | - Nicolaisen, W.
- Christensen, H.
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| Abstract | In the past decade, sinking-out of phytoplankton in the late phases of bloom periods has come to be regarded as an important source of energy-input to the bottom in coastal regions. Estimates of rate of phytoplankton sinking-out were made from studies of the temporal and vertical variations in pelagic chlorophyll-a and combined inorganic nitrogen in the northern Øresund (Denmark) during 1976- 1978. It is concluded that, in this almost permanently stratified water body, sinking-out of phytoplankton to the bottom only took place to a significant degree during the late phase of the spring bloom following a nearly complete depletion of combined nitrogen. This organic input seemed nearly sufficient to cover the annual requirements of the benthos, other sources being at most supplementary. It is hypothesized, that these findings could also apply to at least the deep easternmost part of the Kattegat and that entrainment of deeper water by the surface current could be an important mechanism for re-introducing sinking algal cells to the euphotic zone in the near-permanently stratified inner Danish waters. It appears that, due to the hydrographic conditions, the bottom of me Øresund serves as a trap for phytoplankton from the neighbouring Kattegat. This could explain the comparatively large biomass of benthic invertebrates in the northern Øresund. |
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