Search results for "North sea"
showing 10 items of 30 documents
Plastic ingestion by pelagic and demersal fish from the North Sea and Baltic Sea
2015
Plastic ingestion by marine biota has been reported for a variety of different taxa. In this study, we investigated 290 gastrointestinal tracts of demersal (cod, dab and flounder) and pelagic fish species (herring and mackerel) from the North and Baltic Sea for the occurrence of plastic ingestion. In 5.5% of all investigated fishes, plastic particles were detected, with 74% of all particles being in the microplastic (<5mm) size range. The polymer types of all found particles were analysed by means of Fourier transform infrared (FT-IR) spectroscopy. Almost 40% of the particles consisted of polyethylene (PE). In 3.4% of the demersal and 10.7% of the pelagic individuals, plastic ingestion was …
A risk assessment of the effects of mercury on Baltic Sea, Greater North Sea and North Atlantic wildlife, fish and bivalves
2021
Abstract: A wide range of species, including marine mammals, seabirds, birds of prey, fish and bivalves, were investigated for potential population health risks resulting from contemporary (post 2000) mercury (Hg) exposure, using novel risk thresholds based on literature and de novo contamination data. The main geographic focus is on the Baltic Sea, while data from the same species in adjacent waters, such as the Greater North Sea and North Atlantic, were included for comparative purposes. For marine mammals, 23% of the groups, each composing individuals of a specific sex and maturity from the same species in a specific study region, showed Hg-concentrations within the High Risk Category (H…
Cod at drift in the North Sea
2018
Abstract There has been a large-scale geographical re-distribution of the North Sea cod stock over the past century, and recent surveys indicate a north-eastern modal distribution. Here we assess the consequences of the contemporary distribution of North Sea cod (Gadus morhua) spawning biomass to inter-ocean recruitment potential. By simulations of drifting cod eggs and larvae spawned in the northern North Sea over 16 spawning seasons (in the period 1995–2016), we show that a large portion of the North Sea produced pelagic juveniles most likely settle along the Norwegian Sea shelf. For example during the early 2000s when the North Sea cod spawning biomass was at its lowest, 20% to 27% of la…
Oogenesis and reproductive investment of Atlantic herring are functions of not only present but long-ago environmental influences as well
2017
Following general life history theory, immediate reproductive investment (egg mass × fecundity/body mass) in oviparous teleosts is a consequence of both present and past environmental influences. This clarification questions the frequent use of season-independent (general) fecundity formulas in marine fish recruitment studies based on body metrics only. Here we test the underlying assumption of no lag effect on gametogenesis in the planktivorous, determinate-fecundity Atlantic herring (Clupea harengus) displaying large plasticity in egg mass and fecundity, examining Norwegian summer–autumn spawning herring (NASH), North Sea autumn-spawning herring (NSAH), and Norwegian spring-spawning herri…
Impact of high pCO2 on shell structure of the bivalve Cerastoderma edule
2016
Raised atmospheric emissions of carbon dioxide (CO2) result in an increased ocean pCO2 level and decreased carbonate saturation state. Ocean acidification potentially represents a major threat to calcifying organisms, specifically mollusks. The present study focuses on the impact of elevated pCO2 on shell microstructural and mechanical properties of the bivalve Cerastoderma edule. The mollusks were collected from the Baltic Sea and kept in flow-through systems at six different pCO2 levels from 900 μatm (control) to 24,400 μatm. Extreme pCO2 levels were used to determine the effects of potential leaks from the carbon capture and sequestration sites where CO2 is stored in sub-seabed geologica…
Northern refugia and recent expansion in the North Sea: The case of the wrasse Symphodus melops (Linnaeus, 1758)
2011
Pleistocene climate changes have imposed extreme conditions to intertidal rocky marine communities, forcing many species to significant range shifts in their geographical distributions. Phylogeographic analyses based on both mitochondrial and nuclear genetic markers provide a useful approach to unravel phylogeographic patterns and processes of species after this time period, to gain general knowledge of how climatic changes affect shifts in species distributions. We analyzed these patterns on the corkwing wrasse (Symphodus melops, Labridae), a rocky shore species inhabiting North Sea waters and temperate northeastern Atlantic Ocean from Norway to Morocco including the Azores, using a fragme…
8.2 ka event North Sea hydrography determined by bivalve shell stable isotope geochemistry.
2019
AbstractThe abrupt 8.2 ka cold event has been widely described from Greenland and North Atlantic records. However, its expression in shelf seas is poorly documented, and the temporal resolution of most marine records is inadequate to precisely determine the chronology of major events. A robust hydrographical reconstruction can provide an insight on climatic reaction times to perturbations to the Atlantic Meridional Overturning Circulation. Here we present an annually-resolved temperature and water column stratification reconstruction based on stable isotope geochemistry of Arctica islandica shells from the Fladen Ground (northern North Sea) temporally coherent with Greenland ice core record…
A numerical model of the cloud-topped planetary boundary-layer: Radiation, turbulence and spectral microphysics in marine stratus
1996
A numerical model of the cloud-topped planetary boundary-layer is presented. The model is one-dimensional with special emphasis on a detailed description of cloud microphysical processes. Aerosols and cloud droplets are treated in a two-dimensional particle-distribution whereby the activation of aerosols is calculated explicitly by solving the droplet-growth equation at all relative humidities. Atmospheric radiation is determined with a δ-two-stream radiation scheme. Turbulent fluxes are parametrized as a function of the turbulent kinetic energy. Numerical results are presented which are obtained by utilizing measurements made over the North Sea. The interaction between radiation, turbulenc…
Stabilizing selection on Atlantic cod supergenes through a millennium of extensive exploitation
2022
Life on Earth has been characterized by recurring cycles of ecological stasis and disruption, relating biological eras to geological and climatic transitions through the history of our planet. Due to the increasing degree of ecological abruption caused by human influences many advocate that we now have entered the geological era of the Anthropocene, or “the age of man.” Considering the ongoing mass extinction and ecosystem reshuffling observed worldwide, a better understanding of the drivers of ecological stasis will be a requisite for identifying routes of intervention and mitigation. Ecosystem stability may rely on one or a few keystone species, and the loss of such species could potentia…
Research on the history of Scandinavian summer and seaside tourism – transnational and transregional perspectives?
2013
The purpose of this article is to investigate important research on the history of Scandinavian tourism conducted between the 1980s and the present. More specifically, it deals with research on summer and seaside tourism history in the Skagerrak–Kattegat and some parts of the North Sea region (southeastern Norway, Bohuslan in southwestern Sweden, and Jutland in western Denmark) from the late 1800s through the twentieth century. Although the publications chosen for this historiographical analysis are primarily anthologies and articles in scholarly reports, some monographs have been included as well. The ensuing discussion includes reflections on how the selected geographical spaces may have …