scholarly journals Community structure and bioturbation potential of macrofauna at four North Sea stations with contrasting food supply

1998 ◽  
Vol 173 ◽  
pp. 67-83 ◽  
Author(s):  
B Dauwe ◽  
PMJ Herman ◽  
CHR Heip
Keyword(s):  
Community Structure ◽  
North Sea ◽  
Food Supply

scholarly journals Temporal variability in southern North Sea epifauna communities after the cold winter of 1995/1996

2009 ◽  
Vol 66 (10) ◽  
pp. 2233-2243 ◽  
Author(s):  
Hermann Neumann ◽  
Henning Reiss ◽  
Sebastian Rakers ◽  
Siegfried Ehrich ◽  
Ingrid Kröncke
Keyword(s):  
Community Structure ◽  
North Sea ◽  
Food Supply ◽  
Temporal Variability ◽  
Cold Winter ◽  
Widespread Species ◽  
Southern North Sea ◽  
Oyster Ground ◽  
North Frisian ◽  
Hydroclimatic Change

Abstract Neumann, H., Reiss, H., Rakers, S., Ehrich, S., and Kröncke, I. 2009. Temporal variability in southern North Sea epifauna communities after the cold winter of 1995/1996. – ICES Journal of Marine Science, 66: 2233–2243. Epifauna communities in the southeastern North Sea were studied from 1998 to 2008 to evaluate the effect of hydroclimatic change in community structure. The spatial analysis revealed four communities along the West and North Frisian coasts, on the Oyster Ground, and on the Dogger Bank. The variability between communities was caused mainly by differing abundance of widespread species such as Asterias rubens, probably reflecting differences in environmental conditions, e.g. temperature variation and food supply. Community structure varied between 1998–2000 and 2003–2008 at the shallow West and North Frisian coasts. The hypothesis is that epibenthic communities in these areas were severely affected by the cold winter of 1995/1996, resulting in the outbreak of the opportunistic brittlestar Ophiura albida and followed by characteristic post-disturbance succession stages from 1998 to 2000. The period between 2003 and 2008 was characterized by a continuous decrease in O. albida and by an increase in other species and diversity in the coastal areas. In contrast, secondary production increased in all four areas after 2003, probably because of an increase in sea surface temperature (SST) and in the length of the warming season. We conclude that the cold winter affected epifauna mainly in shallow areas and that the increasing SST influenced the epifauna in the entire southeastern North Sea mainly through an increased food supply.

scholarly journals Observing and modelling phytoplankton community structure in the North Sea

2017 ◽  
Vol 14 (6) ◽  
pp. 1419-1444 ◽  
Author(s):  
David A. Ford ◽  
Johan van der Molen ◽  
Kieran Hyder ◽  
John Bacon ◽  
Rosa Barciela ◽  
...  
Keyword(s):  
Community Structure ◽  
North Sea ◽  
Phytoplankton Community ◽  
Marine Biodiversity ◽  
Phytoplankton Community Structure ◽  
Pigment Analysis ◽  
The North ◽  
The North Sea ◽  
In Situ Observations

Abstract. Phytoplankton form the base of the marine food chain, and knowledge of phytoplankton community structure is fundamental when assessing marine biodiversity. Policy makers and other users require information on marine biodiversity and other aspects of the marine environment for the North Sea, a highly productive European shelf sea. This information must come from a combination of observations and models, but currently the coastal ocean is greatly under-sampled for phytoplankton data, and outputs of phytoplankton community structure from models are therefore not yet frequently validated. This study presents a novel set of in situ observations of phytoplankton community structure for the North Sea using accessory pigment analysis. The observations allow a good understanding of the patterns of surface phytoplankton biomass and community structure in the North Sea for the observed months of August 2010 and 2011. Two physical–biogeochemical ocean models, the biogeochemical components of which are different variants of the widely used European Regional Seas Ecosystem Model (ERSEM), were then validated against these and other observations. Both models were a good match for sea surface temperature observations, and a reasonable match for remotely sensed ocean colour observations. However, the two models displayed very different phytoplankton community structures, with one better matching the in situ observations than the other. Nonetheless, both models shared some similarities with the observations in terms of spatial features and inter-annual variability. An initial comparison of the formulations and parameterizations of the two models suggests that diversity between the parameter settings of model phytoplankton functional types, along with formulations which promote a greater sensitivity to changes in light and nutrients, is key to capturing the observed phytoplankton community structure. These findings will help inform future model development, which should be coupled with detailed validation studies, in order to help facilitate the wider application of marine biogeochemical modelling to user and policy needs.

scholarly journals High-resolution analysis of a North Sea phytoplankton community structure based on in situ flow cytometry observations and potential implication for remote sensing

2015 ◽  
Vol 12 (13) ◽  
pp. 4051-4066 ◽  
Author(s):  
M. Thyssen ◽  
S. Alvain ◽  
A. Lefèbvre ◽  
D. Dessailly ◽  
M. Rijkeboer ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Community Structure ◽  
North Sea ◽  
High Frequency ◽  
Phytoplankton Community ◽  
Phytoplankton Community Structure ◽  
The North ◽  
The North Sea ◽  
Daily Scale

Abstract. Phytoplankton observation in the ocean can be a challenge in oceanography. Accurate estimations of its biomass and dynamics will help to understand ocean ecosystems and refine global climate models. Relevant data sets of phytoplankton defined at a functional level and on a sub-meso- and daily scale are thus required. In order to achieve this, an automated, high-frequency, dedicated scanning flow cytometer (SFC, Cytobuoy b.v., the Netherlands) has been developed to cover the entire size range of phytoplankton cells whilst simultaneously taking pictures of the largest of them. This cytometer was directly connected to the water inlet of a PocketFerryBox during a cruise in the North Sea, 08–12 May 2011 (DYMAPHY project, INTERREG IV A "2 Seas"), in order to identify the phytoplankton community structure of near surface waters (6 m) with a high spatial resolution basis (2.2 ± 1.8 km). Ten groups of cells, distinguished on the basis of their optical pulse shapes, were described (abundance, size estimate, red fluorescence per unit volume). Abundances varied depending on the hydrological status of the traversed waters, reflecting different stages of the North Sea blooming period. Comparisons between several techniques analysing chlorophyll a and the scanning flow cytometer, using the integrated red fluorescence emitted by each counted cell, showed significant correlations. For the first time, the community structure observed from the automated flow cytometry data set was compared with PHYSAT reflectance anomalies over a daily scale. The number of matchups observed between the SFC automated high-frequency in situ sampling and remote sensing was found to be more than 2 times better than when using traditional water sampling strategies. Significant differences in the phytoplankton community structure within the 2 days for which matchups were available suggest that it is possible to label PHYSAT anomalies using automated flow cytometry to resolve not only dominant groups but also community structure.

scholarly journals The feeding and condition of plaice larvae in good and bad plankton patches

1957 ◽  
Vol 36 (3) ◽  
pp. 539-552 ◽  
Author(s):  
J. E. Shelbourne
Keyword(s):  
North Sea ◽  
Physical Condition ◽  
Food Supply ◽  
Food Patch ◽  
Larval Life ◽  
Transition Stage ◽  
Food Items ◽  
Stage Of Development ◽  
Full Swing ◽  
Good Food

In January and March, during the 1955 plaice spawning season, plankton samples were collected with a Heligoland larva net at stations on a grid around a floating radio buoy in the southern North Sea. There was a decided scarcity of suitable food for plaice larvae in the January patch, and this famine was reflected in the deteriorating physical condition of those larvae caught at the transition stage of development, when yolk reserves were becoming exhausted and an adequate external food supply essential. By March, the spring plankton outburst was in full swing. The condition of transitional larvae improved in this good food patch. Feeding started about the mid-yolk phase, mainly on plants. By the time most of the yolk had been resorbed, the appendicularians Oikopleura and Fritillaria had become the principal food items, and remained so throughout pelagic larval life.

Development of macroinvertebrate community structure associated with zebra mussel (Dreissena polymorpha) colonization of artificial substrates

1995 ◽  
Vol 73 (8) ◽  
pp. 1438-1443 ◽  
Author(s):  
Patricia A. Wisenden ◽  
Robert C. Bailey
Keyword(s):  
Community Structure ◽  
Shallow Water ◽  
Food Supply ◽  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Lake Erie ◽  
Zebra Mussels ◽  
Artificial Substrates ◽  
Macroinvertebrate Communities ◽  
Protected Site

We used artificial substrates (rocks < 1500 cm2 surface area) in shallow water (2 m) to assess the development of epilithic macroinvertebrate communities in the presence of zebra mussels. At a turbulent site (Wheatley, Lake Erie), previously colonized (with a non-zebra mussel community) and uncolonized rocks left for 1 year both had lower densities of total invertebrates than previously colonized rocks recovered after only 1 day. As zebra mussels colonized the rocks, Gammarus sp. (amphipods) increased in density, while Chironomini and Tanypodinae (midges), Polycentropus sp. (caddisflies), and Physella sp. and Pleurocera sp. (snails) declined. At a protected site (Stoney Point, Lake St. Clair), previously colonized rocks initially (2 months) had higher densities of many taxa, including zebra mussels, than uncolonized rocks. This difference disappeared after 1 year, as zebra mussels increased on all rocks. Gammarus sp. maintained its numbers, while Tricladida (flatworms) increased and Oecetis sp. (caddisflies), Physella sp., Pleurocera sp., and Tanypodinae declined. Although a similar "zebra mussel – amphipod" community developed on rocks at both sites, we hypothesize that at the turbulent site, zebra mussels and amphipods have a shared tolerance of unstable habitats, and zebra mussels facilitate amphipod colonization of rocks by increasing microhabitat stability and food supply. At the protected site, zebra mussels outcompete other surface dwellers like snails for space, and facilitate the colonization of scavenger–omnivores like amphipods and flatworms.

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