10.14466/CEFASDATAHUB.22
Cefas
Cefas
Structure and function assessment of macrobenthic communities
Cefas
2016
Dataset
Benthic
Benthos
Biota abundance, biomass and diversity
Fauna abundance per unit area of the bed
Birchenough, Silvana
Silvana
Birchenough
Silvana Birchenough
Parker, Ruth
Ruth
Parker
Ruth Parker
Bolam, Stefan
Stefan
Bolam
Stefan Bolan
Painting, Suzanne
Suzanne
Painting
Suzanne Painting
2007-02-01/2007-10-31
en
1
Open Government Licence v3.0
Four infaunal replicate samples were collected at each site using 0.1 m2 Nioz corers (diameter of approximately 30 cm) were sieved on a 1mm mesh sieve, the sieve remains were then sorted and preserved following the methodology described by Boyd (2002). On return, to the laboratory all the infaunal samples were identified to the lowest taxonomic level as possible, counted and weighted.
Five epifaunal replicate samples were collected at each site using 2 m beam trawls during each of the five research cruises. Each trawl was conducted at a constant speed (~2 knots per minute) and sampled an area of seabed of approximately 400 m2. Once on board, the contents of the trawl were sieved over 5mm mesh and all retained individuals were identified, counted and weighed. In some cases, the very high numbers of some groups (e.g. brittle stars, shrimps, and small fish) needed sub-sampling before counting and weighting.
The raw abundance and biomass data for both the infauna (from the cores) and epifauna (trawls) were scaled to values per m2. As some taxa were present in both datasets, taxa which were more appropriately classed as infauna and/or their densities were better estimated via a corer were classed as infauna and removed from the trawl data. Accordingly, those taxa which were generally considered as epifaunal (and their numbers and biomasses better estimated using a trawl) were considered as epifaunal and/or their densities more suitably estimated using a trawl were reported as epifauna.
Five research cruises were conducted (during February, April, May, September and October, 2007) at three study sites, north of the Dogger Bank (hereafter as DB) (55.68 º N, 2.28 º E), the Oyster Ground (54.41º N, 4.04º E) (hereafter as OG) and at Sean Gas Field (hereafter SGF) (53.17º N, 2.81º E). Previous research conducted at the sites, have shown that these sites have representative characteristics of larger regions with similar water column and seabed attributes, considering them as eco-hydrodynamic regions in the southern and central North Sea (see van der Molen et al., 2012; Painting and Foster, 2013).
At each site four replicate samples were collected with a 0.1 m2 Nioz corer to sample benthic infauna and sediments. From each Nioz corer, a small corer (internal diameter of 5.5 cm) was used to obtain sediments for the analysis of particle size, porosity, chlorophyll a/phaeopigment and organic carbon analysis. These cores were sliced at 0.5 to 1 cm intervals up to 10cm depth and stored at -20°C.