The Davis Strait - DCE - Nationalt Center for Miljø og Energi

egistered in the area. A similar pattern was found on a local scale along a
fjord-ocean transect in the Godthaabsfjord/Fylla Bank area (64°N). Here, up
to >80 species per 0.1 m 2 grab sample were reported, and large differences in
habitat characteristics between the 9 sampling stations (47-956 m in depth)
affected the species composition significantly, resulting in a high total species
richness (339 species) (Sejr et al. 2010a). In the two studies, species accumulation
curves (i.e. plots of no. of species vs. no. of samples) showed no
sign of reaching an asymptote, which suggested the ‘true’ number of species
to be considerably higher than observed. An increase in sampling effort is
therefore likely to lead to the observation of new species. These two data sets
contributed to a recent pan-Arctic inventory of macro- and megabenthic
species including all existing data from Arctic shelf regions. Although a lack
of data from Greenland waters was apparent, enough data was available to
suggest species diversity in West Greenland to be in the high end compared
to other ecoregions in the Arctic (Piepenburg et al. 2010).
In May 2010 another benthic sampling campaign was performed in the nearshore
area between 64 and 61°N (Batty et al. 2010). Detailed taxonomic data
are not yet available, but the sampling is expected to provide data on benthic
biomass, abundance, diversity and species composition as well as the physico-chemical
characteristics of the sediment. Visual examinations of the seabed
using an underwater drop camera down to 250 m in depth indicated
that the sea floor was very heterogeneous. Several substrate types were registered
ranging from soft mud and clay to a mix of stones and shells, and
clean rock. The species composition of epifauna was obviously influenced by
these different physical conditions, and several different epifaunal communities
were identified. Due to the reported heterogeneity in the area, it can be
expected to host several different assemblages of epi- and endobenthic species.
As regards the functional role of the benthos in the assessment area, recent
studies in coastal areas indicate that macrozoobenthos are key both in terms
of elemental cycling and ecosystem function. In Kobbefjord (64°N) the annual
carbon demand of the dominating species, sea urchins (Strongylocentrotus
droebachiensis, Fig. 4.3.1) and scallops (Chlamys islandica), corresponded to as
much as 21-45% of the pelagic primary production (Blicher et al. 2009).
Moreover, it is well established that macrozoobenthos stimulate microbial
mineralisation of organic material through bioturbation and bioirrigation,
and faeces production (Glud et al. 2003, Vopel et al. 2003, Glud et al. 2010).
The functional importance of shallow macrofauna was further demonstrated
in a study in Nipisat Sound (64°N), a key habitat for wintering eiders. Here
it was estimated that eiders consumed a significant fraction of the available
macrofauna biomass to balance their costs of living during their wintering.
Their energy demand corresponded to as much as 58% of the total annual
production of macrobenthos in the area (Blicher et al. 2011).
Thus, the available studies from the assessment area agree with the results
from other areas in Greenland, and in the Arctic as a whole, in that the benthic
habitat plays a key role in terms of biodiversity and ecosystem function.
However, the lack of studies of spatial and temporal variation in community
structure, and the lack of data from certain habitat types and from offshore
areas make it difficult to draw more detailed conclusions.
One obvious problem as regards quantitative taxonomical studies of benthos
is that the majority of samples have been collected at sites with soft sediment
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