A synopsis of the macrobenthic assemblages and benthic ETS activity in the Dutch sector of the North Sea
Duineveld, G.C.A.; de Wilde, P.A.W.J.; Kok, A. (1990). A synopsis of the macrobenthic assemblages and benthic ETS activity in the Dutch sector of the North Sea. Neth. J. Sea Res. 26(1): 125-138 In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, more |  |
| Authors | | Top | - Duineveld, G.C.A., more
- de Wilde, P.A.W.J.
- Kok, A.
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| Abstract | Macrobenthos composition and benthic ETS activity were studied at 70 stations in the Dutch exclusive economic zone of the North Sea during the ICES North Sea Benthos survey, April 1986. On the basis of macrofaunal similarity, the stations were grouped into 4 clusters corresponding with the following geographical regions: the area north of Dogger Bank, the Oyster Ground, Dogger Bank proper plus the northern part of the Southern Bight, and the southern part of the Southern Bight. Since each of these areas has a characteristic sediment composition and depth range, the 4 clusters were described as 'deep muddy-sand', 'shallow muddy-sand', 'shallow fine-sand', and 'shallow coarse (medium)-sand', respectively. Biomass, species richness and abundances of the major taxonomical groups, as well as of the total macrofauna, were on average lowest in the shallow coarse-sand cluster. Highest species richness was found in the deep muddy-sand cluster and highest abundances of macro-fauna were found in the shallow muddy-sand cluster. Biomass values of the clusters showed a wide variation due to the occasional presence of heavy individuals of a few rare species. A zone with high biomass levels was found along the southern edge of the Oyster Ground. On the basis of the synoptical measurements of the ETS activity in the sediment, 3 zones with different levels of potential metabolic activity were delimited. No simple relationships could be established between single abiotic or biotic parameters and ETS values. The generally low share of the surface layer (0 -1 cm) in the activity of the whole core (0 - 10 cm) points to depletion of easily metabolizable organic material by the end of the winter. In the Southern Bight, the share of surface activity was highest, which could indicate recent deposition of organic material derived from early-spring blooms. |
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