Ecosystem characteristics and processes facilitating persistent macrobenthic biomass hotspots and associated benthivory in the Pacific Arctic

The contiguous domains of Arctic Ocean advection: Trails of life and death

Distribution of endemic cetaceans in relation to hydrocarbon development and commercial shipping in a warming Arctic

The temporal and spatial dynamics of primary and secondary biomass/production in the Barents Sea since the late 1990s are examined using remote sensing data, observations and a coupled physical-biological model. Field observations of mesozooplankton biomass, and chlorophyll a data from transects (different seasons) and large-scale surveys (autumn) were used for validation of the remote sensing products and modeling results. The validation showed that satellite data are well suited to study temporal and spatial dynamics of chlorophyll a in the Barents Sea and that the model is an essential tool for secondary production estimates. Temperature, open water area, chlorophyll a, and zooplankton biomass show large interannual variations in the Barents Sea. The climatic variability is strongest in the northern and eastern parts. The moderate increase in net primary production evident in this study is likely an ecosystem response to changes in climate during the same period. Increased open water area and duration of open water season, which are related to elevated temperatures, appear to be the key drivers of the changes in annual net primary production that has occurred in the northern and eastern areas of this ecosystem. The temporal and spatial variability in zooplankton biomass appears to be controlled largely by predation pressure. In the southeastern Barents Sea, statistically significant linkages were observed between chlorophyll a and zooplankton biomass, as well as between net primary production and fish biomass, indicating bottom-up trophic interactions in this region.

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Productivity in the Barents Sea - Response to recent climate variability

Todays physical oceanography and primary and secondary production was investigated for the entire Arctic Ocean with the physical-biologically coupled SINMOD model. To obtain indications on the effect of climate change in the 21th century the magnitude of change, and where and when these may take place SINMOD was forced with down-scaled climate trajectories of the International Panel of Climate Change with the A1B climate scenario which appears to predict an average global atmospheric temperature increase of 3.5 to 4 °C at the end of this century. It is projected that some surface water features of the physical oceanography in the Arctic Ocean and adjacent regions will change considerably. The largest changes will occur along the continuous domains of Pacific and in particular regarding Atlantic Water advection and the inflow shelves. Withdrawal of ice will increase primary production, but stratification will persist or, for the most, get stronger as a function of ice-melt and thermal warming along the inflow shelves. Thus the nutrient dependent new and harvestable production will not increase proportionally with increasing photosynthetic active radiation. The greatest increases in primary production are found along the Eurasian perimeter of the Arctic Ocean (up to 40 g C m-2 y-1) and in particular in the northern Barents and Kara Seas (40-80 g C m-2 y-1) where less ice-cover implies less Arctic Water and thus less stratification. Along the shelf break engirdling the Arctic Ocean upwelling and vertical mixing supplies nutrients to the euphotic zone when ice-cover withdraws northwards. The production of Arctic copepods along the Eurasian perimeter of the Arctic Ocean will increase significantly by the end of this century (2-4 g C m-2 y-1). Primary and secondary production will decrease along the southern sections of the continuous advection domains of Pacific and Atlantic Water due to increasing thermal stratification. In the central Arctic Ocean primary production will not increase much due to stratification-induced nutrient limitation.

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Physical constrains and productivity in the future Arctic Ocean

https://escholarship.org/content/qt4sc572cp/qt4sc572cp.pdf?t=nvwmkj

The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

Polar cod (Boreogadus saida) play an integral part in the Arctic ecosystems linking the upper and lower trophic levels. Though their estimated biomass is considerable, recent knowledge of their diets in the US Beaufort Sea is sparse. Collections of polar cod from the US Beaufort Sea were made during August 2008 using demersal and pelagic trawls. Polar cod diet composition was quantified as percent prey weight, percent prey count, and frequency of occurrence of prey. The diet composition between the demersal- and pelagic-captured cod showed differences in all these categories. Polar cod captured in the demersal nets primarily fed on fish (by weight), and pelagic cod primarily fed on copepods (frequency of occurrence) and euphausiids (by weight). In general, these dominant preys are different than what has been reported in other studies describing polar cod diets.

Andy Whitehouse

Papers

The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

The diets of polar cod ( Boreogadus saida ) from August 2008 in the US Beaufort Sea