scholarly journals Spatial heterogeneity in the structure of the planktonic food web in the North Sea

1998 ◽  
Vol 168 ◽  
pp. 197-211 ◽  
Author(s):  
K Richardson ◽  
TG Nielsen ◽  
FB Pedersen ◽  
JP Heilmann ◽  
B Løkkegaard ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Food Web ◽  
North Sea ◽  
The North ◽  
Planktonic Food ◽  
The North Sea

Feeding, Growth and Reproduction of the Marine Planktonic Copepod Pseudo-Calanus Elongatus Boeck

1976 ◽  
Vol 56 (2) ◽  
pp. 327-344 ◽  
Author(s):  
G.-A. Paffenhöfer ◽  
R. P. Harris
Keyword(s):  
Food Web ◽  
North Sea ◽  
Calanoid Copepods ◽  
Small Copepod ◽  
The North ◽  
Controlled Conditions ◽  
Food Concentrations ◽  
Food Species ◽  
The North Sea ◽  
Growth And Reproduction

INTRODUCTIONThe development of techniques to culture calanoid copepods over multiple generations in the laboratory has resulted in considerable advances in knowledge about a group of animals of major importance in the marine food web. A series of extensive studies have been made of two species of large calanoids, Calanus helgolandicus (Claus) (Mullin & Brooks, 1967, 1970a, 1970b; Paffenhöfer, 1970, 1971, 1976a, 1976b), and Rhincalanus nasutus Giesbrecht (Mullin & Brooks, 1967, 1970a, 1970b). Feeding, growth, and reproduction have been studied under controlled conditions, using different temperatures, food species, and food concentrations. Some of the information gained in these studies has been incorporated into a simulation model of the planktonic ecosystem of the North Sea (Steele, 1974). However, in the North Sea and in many other sea areas species of small copepod probably form an important component of the food web. Little information is available on the quantitative biology of these small copepods under controlled conditions.

Large-scale responses of nematode communities to chronic otter-trawl disturbance

2008 ◽  
Vol 65 (4) ◽  
pp. 723-732 ◽  
Author(s):  
Hilmar Hinz ◽  
Jan G Hiddink ◽  
James Forde ◽  
Michel J Kaiser
Keyword(s):  
Food Web ◽  
North Sea ◽  
Large Scale ◽  
Life Cycles ◽  
Irish Sea ◽  
Otter Trawl ◽  
Food Web Structure ◽  
Nematode Communities ◽  
The North ◽  
The North Sea

Nematodes, because of their small size and short life cycles, are thought to be less affected by direct trawling mortality compared with the larger macrofauna. However, nematodes may still be indirectly affected by the physical disturbance of trawling through changing sediment characteristics and food web structure. We determined whether nematode communities on two muddy fishing grounds located in the North Sea and Irish Sea were affected by chronic otter-trawl disturbance and quantified these effects. Nematode abundance, production, and genus richness declined in response to trawling within both areas. Nematode biomass did not respond to trawling intensity. Genus composition was affected by trawling only in the North Sea. The responses in abundance of individual nematode genera to increasing trawling intensity were negative as well as positive. These results indicate that despite their size and fast life cycle, nematodes are affected by intensive trawling on muddy fishing grounds. The loss in secondary production from nematodes can have far-reaching consequences for the integrity of the benthic food web. As bottom trawl fisheries are expanding into ever deeper muddy habitats, the results presented here are an important step towards understanding the global ecosystem effects of bottom trawling.

Decadal changes in the North Sea food web between 1981 and 1991 — implications for fish stock assessment

2006 ◽  
Vol 63 (11) ◽  
pp. 2586-2602 ◽  
Author(s):  
Alexander Kempf ◽  
Jens Floeter ◽  
Axel Temming
Keyword(s):  
Food Web ◽  
North Sea ◽  
Fish Stock ◽  
Fish Diet ◽  
Data Set ◽  
The North ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The North Sea ◽  
The Impact

The North Sea ecosystem of the early 1980s differed substantially from that of the early 1990s. The current North Sea multispecies fisheries assessment models are parameterized by fish diet data sets that reflect both ecosystem states, as the stomachs were sampled in 1981 and 1991. In this study, multispecies virtual population analysis (MSVPA) was parameterized with either diet data set, leading to different model food webs, each representing the predator's diet selection behavior and spatiotemporal overlap with their prey in the two respective ecosystem states. The impact of these changes in predator preferences and spatiotemporal overlap on recruitment success and on stock developments could be demonstrated by using either stomach data set to estimate historic and future spawning stock biomass and recruitment trajectories. The observed changes in the food web mainly impacted the hindcasted recruitment trajectories, whereas spawning stock biomass estimates were quite robust. In the prediction runs, the differences in the survival rate of the recruits decided whether fish stocks of commercially important species (e.g., Gadus morhua, Merlangius merlangus) would recover or collapse in the near future.

Introduction into the ecosystem of the North Sea: Hydrography, biota, and food web relationships

1992 ◽  
Vol 26 (1) ◽  
pp. 7-18 ◽  
Author(s):  
P. A. W. J. Wilde ◽  
M. I. Jenness ◽  
G. C. A. Duineveld
Keyword(s):  
Food Web ◽  
North Sea ◽  
The North ◽  
The North Sea

scholarly journals North Sea ecosystem change from swimming crabs to seagulls

2012 ◽  
Vol 8 (5) ◽  
pp. 821-824 ◽  
Author(s):  
C. Luczak ◽  
G. Beaugrand ◽  
J. A. Lindley ◽  
J-M. Dewarumez ◽  
P. J. Dubois ◽  
...  
Keyword(s):  
Food Web ◽  
North Sea ◽  
Terrestrial Ecosystems ◽  
Ecosystem Change ◽  
Sea Temperature ◽  
The North ◽  
The North Sea ◽  
Important Food Source ◽  
Induced Changes ◽  
Swimming Crabs

A recent increase in sea temperature has established a new ecosystem dynamic regime in the North Sea. Climate-induced changes in decapods have played an important role. Here, we reveal a coincident increase in the abundance of swimming crabs and lesser black-backed gull colonies in the North Sea, both in time and in space. Swimming crabs are an important food source for lesser black-backed gulls during the breeding season. Inhabiting the land, but feeding mainly at sea, lesser black-backed gulls provide a link between marine and terrestrial ecosystems, since the bottom-up influence of allochthonous nutrient input from seabirds to coastal soils can structure the terrestrial food web. We, therefore, suggest that climate-driven changes in trophic interactions in the marine food web may also have ensuing ramifications for the coastal ecology of the North Sea.

scholarly journals An approach for coupling higher and lower levels in marine ecosystem models and its application to the North Sea

2015 ◽  
Vol 8 (7) ◽  
pp. 5577-5618 ◽  
Author(s):  
J. A. Beecham ◽  
J. Bruggeman ◽  
J. Aldridge ◽  
S. Mackinson
Keyword(s):  
Environmental Change ◽  
Food Web ◽  
North Sea ◽  
Trophic Level ◽  
Coupled Model ◽  
Trophic Levels ◽  
Biogeochemical Model ◽  
The North ◽  
The North Sea

Abstract. End to end modelling is an attractive and rapidly developing approach to solve developing strategies in marine systems science and management. However problems remain in the area of data matching and sub-model compatibility. A mechanism and novel interfacing system (Couplerlib) is presented whereby a physical/biogeochemical model (GOTM-ERSEM) that predicts dynamics of the lower trophic level (LTL) organisms in marine ecosystems is coupled to a dynamic ecosystem model (Ecosim) that predicts food-web interactions among higher trophic level (HTL) organisms. Coupling is achieved by means of a bespoke interface which handles the system incompatibilities between the models and a more generic Couplerlib library which uses metadata descriptions in extensible mark-up language (XML) to marshal data between groups, paying attention to functional group mappings and compatibility of units between models. In addition, within Couplerlib, models can be coupled across networks by means of socket mechanisms. As a demonstration of this approach, a food web model (Ecopath with Ecosim, EwE) and a physical/biogeochemical model (GOTM-ERSEM) representing the North Sea ecosystem were joined with Couplerlib. The output from GOTM-ERSEM varies between years dependent on oceanographic and meteorological conditions. Although inter-annual variability was clearly present, there was always the tendency for an annual cycle consisting of a peak of diatoms in spring, followed by (less nutritious) flagellates and dinoflagellates through the summer resulting in an early summer peak in the mesozooplankton biomass. Pelagic productivity, predicted by the LTL model, was highly seasonal with little winter food for the higher trophic levels. The Ecosim model was originally based on the assumption of constant annual inputs and, consequently, when coupled, pelagic species suffered population loss over the winter months. By contrast, benthic populations were more stable (although the benthic linkage modelled was purely at the detritus level). The coupled model was used to examine long term effects of environmental change, and showed the system to be nutrient limited, relatively unaffected by forecast climate change, especially in the benthos. The stability of an Ecosim formulation for large higher tropic level food webs is discussed and it is concluded that this kind of coupled model formulation is better for examining the effects of long term environmental change than short term perturbations.

A Modular Approach for Modelling of the North Sea Ecosystem

1991 ◽  
Vol 24 (10) ◽  
pp. 1-8 ◽  
Author(s):  
A. Malmgren-Hansen ◽  
J. W. Baretta ◽  
P. Ruardij
Keyword(s):  
Food Web ◽  
North Sea ◽  
Algal Growth ◽  
Ecosystem Model ◽  
Trophic Levels ◽  
Basic Knowledge ◽  
Modular Approach ◽  
The North ◽  
The North Sea

A modular approach for generating an ecosystem model for the North Sea is presented. The model structure consists of modules describing physical, chemical and biological processes. The modular approach is selected to facilitate stepwise improvements in the total ecosystem model by replacing existing modules with improved modules being developed. The modules constituting the pelagic ecosystem describe the biological and chemical dynamics of particle production and dissolution simulating the flux of carbon and nutrients (N, P, Si) through the food web. This might be done as a suite of submodules based on functional groups of organisms or as modules describing the different trophic levels based on size distributions. Algal growth is dependent on cellular content of the limiting nutrient, or on net photosynthesis, whichever is the most restricting, allowing for “luxury uptake” of nutrients which may be stored for subsequent periods of shortage. The role of bacteria and other microorganisms is emphasized in recognition of the importance of the “microbial loop”. The Zooplankton module describes prey ingestion in terms of feeding behaviour and the partitioning of ingested carbon, nitrogen and phosphorus into growth and reproduction and the losses through respiration, excretion and defecation. The benthic modules concentrate on describing the small food web, since benthic biological activity in terms of carbon flow, as well as mineralization, are often dominated by micro- and meiofauna in the generally soft sediments of the North Sea. Macrobenthos are described as being a major link between the benthic small food web and higher trophic levels in the ecosystem. Higher trophic levels are described in separate modules taking into account in principle the role of fish, mammals and seabirds. Nutrient cycling is described, focusing on the identification and conceptual modelling of the chemical processes and mechanisms in order to describe the relationships between the biology of the North Sea and the nutrient chemistry. This represents a first step towards forecasting the response of the system to long-term changes due to e.g. eutrophication. The modelling of the nutrient sediment-water interaction emphasizes the role of sedimentation of particulates and the regeneration of inorganic components to the water column. This totally modular concept of the North Sea ecosystem model reflects the authors' view on the present state of the North Sea, the basic knowledge about ecosystem behaviour and a way of creating models as a tool for better understanding of the ecosystem and how man affects the North Sea environment.

Levels of Polybrominated Diphenyl Ether (PBDE) Flame Retardants in Animals Representing Different Trophic Levels of the North Sea Food Web

2002 ◽  
Vol 36 (19) ◽  
pp. 4025-4032 ◽  
Author(s):  
Jan P. Boon ◽  
Wilma E. Lewis ◽  
Michael R. Tjoen-A-Choy ◽  
Colin R. Allchin ◽  
Robin J. Law ◽  
...  
Keyword(s):  
Food Web ◽  
North Sea ◽  
Flame Retardants ◽  
Diphenyl Ether ◽  
Polybrominated Diphenyl Ether ◽  
Trophic Levels ◽  
The North ◽  
The North Sea
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