Impact of climatic change on the biological production in the Barents Sea (original) (raw)
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Climate effects on Barents Sea ecosystem dynamics
ICES Journal of Marine Science, 2012
Effects of climate variability and change on sea temperature, currents, and water mass distribution are likely to affect the productivity and structure of high-latitude ecosystems. This paper focuses on the Barents Sea (BS), a productive Arcto-boreal shelf ecosystem sustaining several ecologically and economically important fish species. The water masses in the region are classified as Atlantic, Arctic, and mixed, each having a distinct ecological signature. The pronounced increase in temperature and a reduction in the area covered by Arctic water that has taken place during the past decade have affected the ecology of the region. An increase in biomass of lipid-rich euphausiids in recent years, possibly linked to the temperature increase, has apparently provided good feeding and growth conditions for several species, including capelin and young cod. The observed reduction in Arctic zooplankton may on the other hand have negative implications for polar cod and other zooplankton predators linked to the Arctic foodweb. Despite these changes, the BS at present seems to maintain relatively stable levels of boreal zooplankton biomass and production, with no significant changes in the abundances of Calanus finmarchicus or the episodic immigrant C. helgolandicus.
Deep Sea Research Part Ii Topical Studies in Oceanography, 2007
The principal features of the marine ecosystems in the Barents and Norwegian Seas and some of their responses to climate variations are described. The physical oceanography is dominated by the influx of warm, high-salinity Atlantic Waters from the south and cold, low-salinity waters from the Arctic. Seasonal ice forms in the Barents Sea with maximum coverage typically in March-April. The total mean annual primary production rates are similar in the Barents and Norwegian Seas (80-90 g C m -2), although in the Barents, the production is higher in the Atlantic than in the ice covered Arctic Waters. The zooplankton is dominated by Calanus species, C. finmarchicus in the Atlantic Waters of the Norwegian and Barents Seas, and C. glacialis in the Arctic Waters of the Barents Sea. The fish species in the Norwegian Sea are mostly pelagics such as herring ( Clupea harengus) and blue whiting ( Micromesistius poutassou), while in the Barents Sea there are both pelagics (capelin ( Mallotus villosus Mülle r), herring, and polar cod ( Boreogadus saida Lepechin)) and demersals (cod ( Gadus morhua L.) and haddock ( Melanogrammus aeglefinus)). The latter two species spawn in the Norwegian Sea along the slope edge (haddock) or along the coast (cod) and drift into the Barents Sea. Marine mammals and seabirds, although comprising only a relatively small percentage of the biomass and production in the region, play an important role as consumers of zooplankton and small fish. While top-down control by predators certainly is significant within the two regions, there is also ample evidence of bottom-up control. Climate variability influences the distribution of several fish species, such as cod, herring and blue whiting, with northward shifts during extended warm periods and southward movements during cool periods. Climate-driven increases in primary and secondary production also lead to increased fish production through higher abundance and improved growth rates.
Barents Sea plankton production and controlling factors in a fluctuating climate
ICES Journal of Marine Science, 2021
The Barents Sea and its marine ecosystem is exposed to many different processes related to the seasonal light variability, formation and melting of sea-ice, wind-induced mixing, and exchange of heat and nutrients with neighbouring ocean regions. A global model for the RCP4.5 scenario was downscaled, evaluated, and combined with a biophysical model to study how future variability and trends in temperature, sea-ice concentration, light, and wind-induced mixing potentially affect the lower trophic levels in the Barents Sea marine ecosystem. During the integration period (2010–2070), only a modest change in climate variables and biological production was found, compared to the inter-annual and decadal variability. The most prominent change was projected for the mid-2040s with a sudden decrease in biological production, largely controlled by covarying changes in heat inflow, wind, and sea-ice extent. The northernmost parts exhibited increased access to light during the productive season ...
Scandinavia, parts of northern Europe, and possibly extending into the North Sea and northern and central Britain. The Barents Sea ice sheet was anchored to islands and shallow banks, with fast flowing ice-streams existing in major trough systemsa situation comparable to West Antarctic Ice Sheet today (Howell et al., 1999). Ice streams reached speeds of up to 1km/year, transporting considerable amounts of sediments off the continental shelf, resulting in the rapid growth of several large submarine fans, most notably at the mouth of Bear Island Trough (Howell and Siegert, 2000). Marine life in the Barents Sea, as we know it today, stretches back to the end of the last ice age. There is a layer of post-glacial marine sediment deposited over older, pre-glacial sediments and bedrock. Thickness of this sediment layer varies over the entire sea, due to underwater topography, currents, and re-suspension. A major bottom mapping project, MAREANO http://www.mareano.no, is now in progress to produce detailed information on the structure and topography of the Barents Sea bottom and the benthic life.
ICES Journal of Marine Science, 2012
Long time-series of data from the Barents Sea (BS) are analysed to contrast the climate, fishing pressure, plankton, pelagic fish, demersal fish, and interactions between trophic levels in a recent decade (2000 -2009) with the period 1970 -1999. During the past four decades, fishing pressure and climatic conditions have varied greatly in the BS, and stock levels have fluctuated substantially. Trophic control has changed from mainly bottom -up to top -down, then back to mainly bottom -up. No clear evidence for persistent ecological regimes was found. The past decade has been the warmest on record, with large stocks of demersal and pelagic fish, and increasing abundances of krill and shrimp. Except perhaps for the rather less-studied Arctic species, the short-term effect of the recent warming has been positive for BS stocks. However, as many of the long-established relationships and mechanisms in the BS seem to be changing, the long-term effects of warming are uncertain.
Still Arctic?—The changing Barents Sea
Elem Sci Anth
The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and autumn. Observations over recent decades show that surface air and ocean temperatures have increased, sea-ice extent has decreased, ocean stratification has weakened, and water chemistry and ecosystem components have changed, the latter in a direction often described as “Atlantification” or “borealisation,” with a less “Arctic” appearance. Temporal and spatial changes in the Barents Sea have a wider relevance, both in the context of large-scale climatic (air, water mass and sea-ice) transport processes and in comparison to other Arctic regions. These observed changes also have socioeconomic c...
Potential impact of climate change on ecosystems of the Barents Sea Region
Climatic Change, 2008
The EU project BALANCE (Global Change Vulnerabilities in the Barents region: Linking Arctic Natural Resources, Climate Change and Economies) aims to assess vulnerability to climate change in the Barents Sea Region. As a prerequisite the potential impact of climate change on selected ecosystems of the study area has to be quantified, which is the subject of the present paper. A set of ecosystem models was run to generate baseline and future scenarios for 1990, 2020, 2050 and 2080. The models are based on data from the Regional Climate Model (REMO), driven by a GCM which in turn is forced by the IPCC-B2 scenario. The climate change is documented by means of the Köppen climate classification. Since the multitude of models requires the effect of climate change on individual terrestrial and marine systems to be integrated, the paper concentrates on a standardised visualisation of potential impacts by use of a Geographical Information System for the timeslices 2050 and 2080. The resulting maps show that both terrestrial and marine ecosystems of the Barents region will undergo significant changes until both 2050 and 2080.
Cod and climate variability in the Barents Sea
Climate Research, 2001
Interannual variability of temperature in the Kola section (Barents Sea) and the abundance as 0-group (age 5 mo) and recruits (age 3 yr), spawning stock biomass, and survival of Arcto-Norwegian cod in the Barents Sea were related to climate variability using a multivariate regression model. The results show that in the Barents Sea the temperature anomalies are significantly and highly correlated to climate variables such as large-scale sea-level pressure fields and the North Atlantic Oscillation index. A significant and high correlation was detected between the temperature in the Barents Sea and both the 0-group index and recruitment of Arcto-Norwegian cod. A phase lag of 2 yr appears in recruitment. The high model skill and excellent correlation indicate that it is possible to predict the future development of Arcto-Norwegian cod stocks from climate-change scenarios.
Modelling the ecosystem dynamics of the Barents Sea including the marginal ice zone
Journal of Marine Systems, 2006
An upgraded and revised physically-biologically coupled, nested 3D model with 4 km grid size is applied to investigate the seasonal carbon flux and its interannual variability. The model is validated using field data from the years for which the carbon flux was modelled, focussing on its precision in space and time, the adequacy of the validation data, suspended biomass and vertical export. The model appears to reproduce the space and time (F 1 week and 10 nautical miles) distribution of suspended biomass well, but it underestimates vertical export of carbon at depth. The modelled primary production ranges from 79 to 118 g C m À 2 year À 1 (average 93 g C m À 2 year À 1 ) between 4 different years with higher variability in the ice-covered Arctic (F 26%) than in the Atlantic (F 7%) section. Meteorological forcing has a strong impact on the vertical stratification of the regions dominated by Atlantic water and this results in significant differences in seasonal variability in primary production. The spatially integrated primary production in the Barents Sea is 42-49% greater during warm years than the production during the coolest and most icecovered year. D