Arctic Ocean Research Papers - Academia.edu (original) (raw)

A serologic survey of anti-Brucella spp. antibodies was undertaken on 2,470 samples of 14 North American marine mammal species collected between 1984-97. Serum or blood from eight species of cetaceans and six species of pinnipeds was... more

A serologic survey of anti-Brucella spp. antibodies was undertaken on 2,470 samples of 14 North American marine mammal species collected between 1984-97. Serum or blood from eight species of cetaceans and six species of pinnipeds was sampled from Pacific, Atlantic, and Arctic oceans. Two competitive enzyme-linked immunosorbent assays (C-ELISA's), using specific monoclonal antibodies to Brucella abortus cell wall components, were used to detect anti-Brucella spp. antibodies in the samples. Sera from 33 cetaceans and 61 pinnipeds gave inhibition values, in one or both of the tests, which exceeded the threshold that indicates Brucella spp. exposure in cattle. Seropositive animals were identified from Pacific, Atlantic, and Arctic oceans. While Brucella spp. was not isolated, differences in the response of seropositive cetacean and pinniped sera in the two assays suggest that two antigenically distinct species or biovars of Brucella spp. are present. No pathology consistent with clinical brucellosis was noted in any of the animals tested although detailed examination was not conducted on all carcasses.

In this paper, we have assessed the temporal, spatial and depth related variation of suspended particulate organic matter (POM) in the Bay of Bengal. For this purpose, suspended particulate matter (SPM) samples were collected from eight... more

In this paper, we have assessed the temporal, spatial and depth related variation of suspended particulate organic matter (POM) in the Bay of Bengal. For this purpose, suspended particulate matter (SPM) samples were collected from eight depths (2 to 1000 m) at 9 locations in the Bay of Bengal during July/August 2001 (Southwest monsoon, SWM), September/October 2002 (Fall Intermonsoon, FIM), and March/April 2003 (Spring Inter-monsoon, SPIM). The SPM samples were analyzed for chlorophyll a (Chl a), particulate organic carbon (POC) and total particulate nitrogen (TPN). The surface concentrations of POC varied from 4.3 to 11.1 µM C, 3.1 to 10.9 µM C, and 4.3 to 9.0 µM C during SWM, FIM, and SPIM, respectively. The levels of SPM, and the concentrations of Chl a, and POC were relatively higher in the offshore compared to the near shore stations, especially during SWM. The POC concentration and its contribution to the SPM were higher in the surface waters, and both decreased with increasing water column depth at most of the stations. The observed decrease with depth of POC indicates heterotrophic uptake and/or dilution by inorganic material, poor in POC. This was also reflected in the C/N ratio which generally increased with water column depth. The relatively low C/N and POC/Chl a ratios, and high Chl a and % POC during the SWM and FIM indicate the presence of relatively fresh POM in the Bay during these two seasons. The observed seasonal differences in the quality of POM appears to be governed by river runoff and the physical forces such as eddies which pump nutrients into the surface waters thereby enhancing biological production.

Climate change Land bird species

The first carbon budget constructed for the Barents Sea to study the fluxes of carbon into, out of, and within the region is presented. The budget is based on modelled volume flows, measured dissolved inorganic carbon (DIC) concentration,... more

The first carbon budget constructed for the Barents Sea to study the fluxes of carbon into, out of, and within the region is presented. The budget is based on modelled volume flows, measured dissolved inorganic carbon (DIC) concentration, and literature values for dissolved organic carbon (DOC) and particulate organic carbon (POC) concentrations. The results of the budget show that $ 5600 7 660 Â 10 6 t C yr À 1 is exchanged through the boundaries of the Barents Sea. If a 40% uncertainty in the volume flows is included in the error calculation it resulted in a total uncertainty of 7 1600 Â 10 6 t C yr À 1 . The largest part of the total budget flux consists of DIC advection ( $ 95% of the inflow and $ 97% of the outflow). The other sources and sinks are, in order of importance, advection of organic carbon (DOC +POC; $ 3% of both in-and outflow), total uptake of atmospheric CO 2 ( $ 1% of the inflow), river and land sources ($ 0.2% of the inflow), and burial of organic carbon in the sediments ( $ 0.2% of the outflow). The Barents Sea is a net exporter of carbon to the Arctic Ocean; the net DIC export is $ 2500 7660 Â 10 6 t C yr À 1 of which $ 1700 7 650 Â 10 6 t C yr À 1 ( $ 70%) is in subsurface water masses and thus sequestered from the atmosphere. The net total organic carbon export to the Arctic Ocean is $ 80 720 Â 10 6 t C yr À 1 . Shelf pumping in the Barents Sea results in an uptake of $ 22 7 11 Â 10 6 t C yr À 1 from the atmosphere which is exported out of the area in the dense modified Atlantic Waters. The main part of this carbon was channelled through export production ( $ 167 10 Â 10 6 t C yr À 1 ).

An understanding of microbial interactions in first-year sea ice on Arctic shelves is essential for identifying potential responses of the Arctic Ocean carbon cycle to changing sea-ice conditions. This study assessed dissolved and... more

An understanding of microbial interactions in first-year sea ice on Arctic shelves is essential for identifying potential responses of the Arctic Ocean carbon cycle to changing sea-ice conditions. This study assessed dissolved and particulate organic carbon (DOC, POC), exopolymeric substances (EPS), chlorophyll a, bacteria and protists, in a seasonal (24 February to 20 June 2004) investigation of first-year sea ice and associated surface waters on the Mackenzie Shelf. The dynamics of and relationships between different sea-ice carbon pools were investigated for the periods prior to, during and following the sea-ice-algal bloom, under high and low snow cover. A predominantly heterotrophic sea-ice community was observed prior to the ice-algal bloom under high snow cover only. However, the heterotrophic community persisted throughout the study with bacteria accounting for, on average, 44% of the non-diatom particulate carbon biomass overall the study period. There was an extensive accumulation of sea-ice organic carbon following the onset of the ice-algal bloom, with diatoms driving seasonal and spatial trends in particulate sea-ice biomass. DOC and EPS were also significant sea-ice carbon contributors such that sea-ice DOC concentrations were higher than, or equivalent to, sea-ice-algal carbon concentrations prior to and following the algal bloom, respectively. Sea-ice-algal carbon, DOC and EPScarbon concentrations were significantly interrelated under high and low snow cover during the algal bloom (r values ≥ 0.74, p b 0.01). These relationships suggest that algae are primarily responsible for the large pools of DOC and EPS-carbon and that similar stressors and/or processes could be involved in regulating their release. This study demonstrates that DOC can play a major role in organic carbon cycling on Arctic shelves.

On a transect across the Lomonosov Ridge strati"ed zooplankton tows were made to the bottom at seven stations. A species inventory was established and compared with earlier observations in the Arctic Ocean. Di!erences between the Amundsen... more

On a transect across the Lomonosov Ridge strati"ed zooplankton tows were made to the bottom at seven stations. A species inventory was established and compared with earlier observations in the Arctic Ocean. Di!erences between the Amundsen and Makarov basins are relatively small and correspond well with the general circulation patterns for Atlantic, Paci"c, and neritic waters, suggesting slow mixing rates for the di!erent basins. There were no remarkable di!erences in the species composition or their vertical distribution between the two sides of the Lomonosov Ridge. This indicates e!ective faunistic exchange across the ridge, although several bathy-pelagic species were almost or completely absent on top of the Ridge. Biomass showed a strong gradient along the transect, with a pronounced peak (9.5 g dry weight m\) in the core of Atlantic water over the ridge, and minima over the deep basins. These di!erences were related to the e!ect of bottom topography for deep-living species, and the dynamics of the Atlantic layer for the meso-and epipelagic species. The maximum was formed mainly by the copepods Calanus hyperboreus and Metridia longa together with chaetognaths and ostracods. The presence of young developmental stages in some of the abundant species (C. hyperboreus, M. longa) suggests successful reproduction at all stations but C. xnmarchicus was almost exclusively represented as old stages and adults. Comparison with earlier data on abundance and biomass from the Canada Basin (Russian Drift station`North Pole-22a) shows a pronounced di!erence with respect to both absolute quantities and relative composition. The copepod C.

Changes in the Arctic atmosphere, cryosphere and Ocean are drastically altering the dynamics of phytoplankton, the base of marine ecosystems. This Review addresses four major complementary questions of ongoing Arctic Ocean changes and... more

Changes in the Arctic atmosphere, cryosphere and Ocean are drastically altering the dynamics of phytoplankton, the base of
marine ecosystems. This Review addresses four major complementary questions of ongoing Arctic Ocean changes and associated
impacts on phytoplankton productivity, phenology and assemblage composition. We highlight trends in primary production
over the last two decades while considering how multiple environmental drivers shape Arctic biogeography. Further, we
consider changes to Arctic phenology by borealization and hidden under-ice blooms, and how the diversity of phytoplankton
assemblages might evolve in a novel Arctic ‘biogeochemical landscape’. It is critical to understand these aspects of changing
Arctic phytoplankton dynamics as they exert pressure on marine Arctic ecosystems in addition to direct effects from rapid
environmental changes.

As the planet cooled from peak warmth in the early Cenozoic, extensive Northern Hemisphere ice sheets developed by 2.6 Ma ago, leading to changes in the circulation of both the atmosphere and oceans. From w2.6 to w1.0 Ma ago, ice sheets... more

As the planet cooled from peak warmth in the early Cenozoic, extensive Northern Hemisphere ice sheets developed by 2.6 Ma ago, leading to changes in the circulation of both the atmosphere and oceans. From w2.6 to w1.0 Ma ago, ice sheets came and went about every 41 ka, in pace with cycles in the tilt of Earth's axis, but for the past 700 ka, glacial cycles have been longer, lasting w100 ka, separated by brief, warm interglaciations, when sea level and ice volumes were close to present. The cause of the shift from 41 ka to 100 ka glacial cycles is still debated. During the penultimate interglaciation, w130 to w120 ka ago, solar energy in summer in the Arctic was greater than at any time subsequently. As a consequence, Arctic summers were w5 C warmer than at present, and almost all glaciers melted completely except for the Greenland Ice Sheet, and even it was reduced in size substantially from its present extent. With the loss of land ice, sea level was about 5 m higher than present, with the extra melt coming from both Greenland and Antarctica as well as small glaciers. The Last Glacial Maximum (LGM) peaked w21 ka ago, when mean annual temperatures over parts of the Arctic were as much as 20 C lower than at present. Ice recession was well underway 16 ka ago, and most of the Northern Hemisphere ice sheets had melted by 6 ka ago. Solar energy reached a summer maximum (9% higher than at present) w11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1e3 C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present. Early Holocene summer sea ice limits were substantially smaller than their 20th century average, and the flow of Atlantic water into the Arctic Ocean was substantially greater. As summer solar energy decreased in the second half of the Holocene, glaciers reestablished or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean Quaternary Science Reviews 29 diminished. Late Holocene cooling reached its nadir during the Little Ice Age (about 1250e1850 AD), when sun-blocking volcanic eruptions and perhaps other causes added to the orbital cooling, allowing most Arctic glaciers to reach their maximum Holocene extent. During the warming of the past century, glaciers have receded throughout the Arctic, terrestrial ecosystems have advanced northward, and perennial Arctic Ocean sea ice has diminished.

The draft paper as at 24th April which is updated from the draft made for the oral presentation session (5th April 2017 does not contain any references and text errors needed corrections). The paper is still being worked on with more... more

The draft paper as at 24th April which is updated from the draft made for the oral presentation session (5th April 2017 does not contain any references and text errors needed corrections). The paper is still being worked on with more sections being added with some aspect areas clarified in more detail. Others are being reviewed. Due to the closure of the Parliament in the UK early for the snap elections, the text is still unfinished and will be resumed for the new Parliament session with no end date set yet. The document is best viewed by a download to Microsoft Word as web browsers tend to muddle the layout. Please note that the ice sheet mass balance changes occur mainly in nearby Iceland, Jan Mayen and the Mid-Atlantic Ridge rather than Greenland itself. (High viscous, low nucleation events pushing very cool, effusive, almost 'solid' lava incursions vertically up like the Mascarene volcanism of Mauritius are rare anomalies from a misaligned hotspot influencing further afield - and therefore far less likely.)

Citation: O'Connor, F. M., et al. (2010), Possible role of wetlands, permafrost, and methane hydrates in the methane cycle under future climate change: A review, Rev. Geophys., 48, RG4005,

The recent warming in the Arctic is affecting a broad spectrum of physical, ecological, and human/cultural systems that may be irreversible on century time scales, and have the potential to cause rapid changes in the earth system. The... more

The recent warming in the Arctic is affecting a broad spectrum of physical, ecological, and human/cultural systems that may be irreversible on century time scales, and have the potential to cause rapid changes in the earth system. The response of the carbon cycle of the Arctic to changes in climate is a major issue of global concern, yet there has not been a comprehensive review of the status of the contemporary carbon cycle of the Arctic and its response to climate change. This review is designed to clarify key uncertainties and vulnerabilities in the response of the carbon cycle of the Arctic to ongoing climatic change. While it is clear that there are substantial stocks of carbon in the Arctic, there are also significant uncertainties associated with the magnitude of organic matter stocks contained in permafrost and the storage of methane hydrates beneath both subterranean and submerged permafrost of the Arctic. In the context of the global carbon cycle, this review demonstrates that the Arctic plays an important role in the global dynamics of both CO 2 and CH 4 . Studies suggest that the Arctic has been a sink for atmospheric CO 2 of between 0 and 0.8 Pg C/yr in recent decades, which is between 0% and 25% of the global net land/ocean flux during the 1990s. The Arctic is a substantial source of CH 4 to the atmosphere (between 32 and 112 Tg CH 4 /yr), primarily because of the large area of wetlands throughout the region. Analyses to date indicate that the sensitivity of the carbon cycle of the Arctic during the remainder of the 21st century is highly uncertain. To improve the capability to assess the sensitivity of the carbon cycle of the Arctic to projected climate change, we recommend that (1) integrated regional studies be conducted to link observations of carbon dynamics to the processes that are likely to influence those dynamics, and (2) the understanding gained from these integrated studies be incorporated into both uncoupled and fully coupled carbon-climate modeling efforts.

With current scientific models forecasting an ice-free Central Arctic Ocean (CAO) in summer by mid-century and potentially earlier, a direct shipping route via the North Pole connecting markets in Asia, North America, and Europe may soon... more

With current scientific models forecasting an ice-free Central Arctic Ocean (CAO) in summer by mid-century and potentially earlier, a direct shipping route via the North Pole connecting markets in Asia, North America, and Europe may soon open. The Transpolar Sea Route (TSR) would represent a third Arctic shipping route in addition to the Northern Sea Route and Northwest Passage. In response to the continued decline of sea ice thickness and extent and growing recognition within the Arctic and global governance communities of the need to anticipate and regulate commercial activities in the CAO, this paper examines: (i) the latest estimates of the TSR's opening; (ii) scenarios for its commercial and logistical development, addressing the various transportation systems that could evolve; (iii) the geopolitics of the TSR, focusing on international and national regulations and the roles of Russia, a historic power in the Arctic, and China, an emerging one; and (iv) the environmental and socioeconomic consequences of transpolar shipping for local and Indigenous residents of communities along the TSR's entrances. Our analysis seeks to inform national and international policymaking with regard to the TSR because although climate change is proceeding rapidly, within typical policymaking timescales, there is still time to prepare for the emergence of the new Arctic shipping corridor.

Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of... more

Arctic sea-ice extent and volume are declining rapidly. Several studies project that the Arctic Ocean may become seasonally ice-free by the year 2040 or even earlier. Putting this into perspective requires information on the history of Arctic sea-ice conditions through the geologic past. This information can be provided by proxy records from the Arctic Ocean floor and from the surrounding coasts. Although existing records are far from complete, they indicate that sea ice became a feature of the Arctic by 47 Ma, following a pronounced decline in atmospheric pCO 2 after the Paleocene-Eocene Thermal Optimum, and consistently covered at least part of the Arctic Ocean for no less than the last 13-14 million years. Ice was apparently most widespread during the last 2-3 million years, in accordance with Earth's overall cooler climate. Nevertheless, episodes of considerably reduced sea ice or even seasonally ice-free conditions occurred during warmer periods linked to orbital variations. The last low-ice event related to orbital forcing (high insolation) was in the early Holocene, after which the northern high latitudes cooled overall, with some superimposed shorterterm (multidecadal to millennial-scale) and lower-magnitude variability. The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.

Pronounced changes in temperature, salinity (density) and upwelling have occurred in surface and deeper waters of the oceans, contributing with changing patterns and strength of winds to an alteration in ocean circulation. Together these... more

Pronounced changes in temperature, salinity (density) and upwelling have occurred in surface and deeper waters of the oceans, contributing with changing patterns and strength of winds to an alteration in ocean circulation. Together these changes have a potentially large impact through feedbacks on climate change.

Portrayal of North American ice cover during the Last Glacial Maximum is dominated by the Laurentide Ice Sheet, leaving little detail for the adjacent Innuitian Ice Sheet (IIS). Four decades of geological fieldwork across the Queen... more

Portrayal of North American ice cover during the Last Glacial Maximum is dominated by the Laurentide Ice Sheet, leaving little detail for the adjacent Innuitian Ice Sheet (IIS). Four decades of geological fieldwork across the Queen Elizabeth Islands now warrant specific treatment of the IIS, including its chronology, configuration, dynamics and retreat. This reconstruction is relevant to the sedimentary history of the Arctic Ocean and to high latitude climate forcing. The IIS was composed of both an alpine and lowland sector. The advance of the alpine sector occurred as recently as 19 14 C ka BP. Geological evidence configures outflow from alpine and lowland divides that produced several palaeo-ice streams, one extending northwestward across the Canadian Arctic Archipelago to the polar continental shelf. Retreat of the IIS commenced along its southwest margin 11.614CkaBP.However,mostoftheicesheetremainedonthecontinentalshelfduringtheYoungerDryas.By11.6 14 C ka BP. However, most of the ice sheet remained on the continental shelf during the Younger Dryas. By 11.614CkaBP.However,mostoftheicesheetremainedonthecontinentalshelfduringtheYoungerDryas.By10 14 C ka BP, marine-based ice experienced widespread calving through the western and central archipelago in response to Holocene warming and ongoing eustatic sea level rise. The sea penetrated the eastern archipelago by 8.5 14 C ka BP, gutting the alpine sector of the IIS. Regional isobases record the glacioisostatic signature of the ice sheet, and are congruent with the primary geological evidence. The delayed buildup of the IIS was out-of-phase with the growth of the Laurentide Ice Sheet that occasioned climatic and glacio-eustatic forcing in the Innuitian region. Recent modelling experiments reinforce the hypothesis that growth of the Laurentide Ice Sheet culminated in a split jet stream that temporarily favoured augmented precipitation and growth of the IIS. r

The Arctic has undergone dramatic change during the past decade. The observed changes include atmospheric sea-level pressure, wind fields, sea-ice drift, ice cover, length of melt season, change in precipitation patterns, change in... more

The Arctic has undergone dramatic change during the past decade. The observed changes include atmospheric sea-level pressure, wind fields, sea-ice drift, ice cover, length of melt season, change in precipitation patterns, change in hydrology and change in ocean currents and watermass distribution. It is likely that these primary changes have altered the carbon cycle and biological systems, but the difficulty of observing these together with sporadic, incomplete time series makes it difficult to evaluate what the changes have been. Because contaminants enter global systems and transport through air and water, the changes listed above will clearly alter contaminant pathways. Here, we review what is known about recent changes using the Arctic Oscillation as a proxy to help us understand the forms under which global change will be manifest in the Arctic. For Pb, Cd and Zn, the Arctic is likely to become a more effective trap because precipitation is likely to increase. In the case of Cd, the natural cycle in the ocean appears to have a much greater potential to alter exposure than do human releases of this metal. Mercury has an especially complex cycle in the Arctic including a unique scavenging process (mercury depletion events), biomagnifying foodwebs, and chemical transformations such as methylation. The observation that mercury seems to be increasing in a number of aquatic species whereas atmospheric gaseous mercury shows little sign of change suggests that factors related to change in the physical system (ice cover, permafrost degradation, organic carbon cycling) may be more important than human activities.

A diverse assemblage of acritarchs, prasinophytes and dinoflagellate cysts occurs in an organic rich black mud in Core Fl-533, taken from the Alpha Ridge, Arctic Ocean. Similarities between this assemblage and others described from the... more

A diverse assemblage of acritarchs, prasinophytes and dinoflagellate cysts occurs in an organic rich black mud in Core Fl-533, taken from the Alpha Ridge, Arctic Ocean. Similarities between this assemblage and others described from the Canadian Arctic allow this black mud to be dated as early Maastrichtian, based primarily on the presence of Cerodinium leptodermum, and the absence of exclusively Campanian and upper Maastrichtian taxa. The high abundance of Comasphaeridium and marine derived amorphous organic matter may indicate a shelf to upper slope environment, possibly deposited during a marine transgression. An abundance of prasinophyte algal cysts, a moderately high peridinioid=gonyaulacoid dinoflagellate cyst ratio, and high species diversity indicate high paleoproductivity, most likely associated with upwelling conditions. When interpreted within the context of two nearby biosiliceous-rich Maastrichtian cores also taken from Alpha Ridge, and from paleogeographic reconstructions, these results indicate that an upwelling region probably existed along the eastern Arctic Ocean during at least part of the Maastrichtian, and formed different sedimentary facies in shelf to slope environments, similar to facies patterns recognized in lower latitude paleo-upwelling regions.

The composition and biomass of the zooplankton community within the Canada Basin down to 3000 m was studied during July 2005 at 12 stations. A total of 111 species including 74 species of crustaceans (55 species of copepods, 2... more

The composition and biomass of the zooplankton community within the Canada Basin down to 3000 m was studied during July 2005 at 12 stations. A total of 111 species including 74 species of crustaceans (55 species of copepods, 2 euphausiids, 11 amphipods, 1 decapod, 5 ostracods), 17 cnidarians (12 hydromedusae, 1 scyphomedusae, 4 siphonophora), 1 foraminifera, 4 ctenophores, 2 pteropods, 4 larvaceans, 4 chaetognaths, and 5 polychaetes were identified. Most of the species observed are typical of the Arctic waters, with the notable exception of several Pacific expatriate copepod species, suggesting no zoogeographical barrier between the Canadian and Eurasian basins. Overall species inventories appear unchanged over the past 50 years, and were similar to the Eurasian Basins. Zooplankton biomass averaged 3.670.23 g DW m À2 , with 5050% of the biomass concentrated within the upper 100 m; nonetheless significant biomass and the majority of species diversity occurred below 100 m. Copepods represented 91% of the community numerically, followed by pteropods (2.6%), larvacean (1.8%) and shelled protists (1.5%), with other groups each contributing 1% or less. While copepods represented 85% of the total biomass, chaetognaths represented 13% on average (ca. 50% of non-copepod biomass), followed by cnidarians plus ctenophores (4.6%), ostracods (3.6%), and other groups (502% or less). Species-specific depth preferences and ranges resulted in statistically distinct communities in different depth strata and showed an orderly departure in similarity with increasing distance between strata. In Arctic waters, because temperature varies relatively little over the water column, so should respiratory rates; hence deep-water species are likely to play a greater role in the transfer or recycling of surface production than is typical of other deep ocean communities.

During the Quaternary period, ice sheets centred over the Barents and Kara seas expanded several times onto mainland Russia and blocked northflowing rivers, such as the Yenissei, Ob, Pechora and Mezen. Large ice-dammed lakes with reversed... more

During the Quaternary period, ice sheets centred over the Barents and Kara seas expanded several times onto mainland Russia and blocked northflowing rivers, such as the Yenissei, Ob, Pechora and Mezen. Large ice-dammed lakes with reversed outlets, e.g. toward the Caspian Sea, formed south of these ice sheets. Some lakes are reconstructed from shorelines and lacustrine sediments, others mainly from ice-sheet configuration. Ice-dammed lakes, considerably larger than any lake on Earth today, are reconstructed for the periods 90-80 and 60-50 ka. The ages are based on numerous optically stimulated luminescence (OSL) dates. During the global Last Glacial Maximum (LGM, about 20 ka) the Barents-Kara Ice Sheet was too small to block these eastern rivers, although in contrast to the 90-80 and 60-50 ka maxima, the Scandinavian Ice Sheet grew large enough to divert rivers and meltwater across the drainage divide from the Baltic Basin to the River Volga, and that way to the Caspian Sea. Climate modelling shows that the lakes caused lower summer temperatures on the continent and on the lower parts of the ice sheet. The final drainage of the best mapped lake is modelled, and it is concluded that it probably emptied within few months. We predict that this catastrophic outburst had considerable impact on sea-ice formation in the Arctic Ocean and on the climate of a much larger area. r

The overall objective of AMOC is to develop and desi~n an acoustic system for long-term monitoring of the ocean temperature and ice thickness in the Arctic Ocean. including the Fram Strait, for climate variability studies and global... more

The overall objective of AMOC is to develop and desi~n an acoustic system for long-term monitoring of the ocean temperature and ice thickness in the Arctic Ocean. including the Fram Strait, for climate variability studies and global warming detection.

The Fram Strait is very important with regard to heat and mass exchange in the Arctic Ocean, and the large quantities of heat carried north by the West Spitsbergen Current (WSC) influence the climate in the Arctic region as a whole. A... more

The Fram Strait is very important with regard to heat and mass exchange in the Arctic Ocean, and the large quantities of heat carried north by the West Spitsbergen Current (WSC) influence the climate in the Arctic region as a whole. A large volume of water and ice is transported through Fram Strait, with net water transport of 1.7-3.2 Sv southward in the East Greenland Current and a volume ice flux in the range of 0.06-0.11 Sv. The mean annual ice flux is about 866,000 km 2 yr À1 . The Kongsfjorden-Krossfjorden fjord system on the coast of Spitsbergen, or at the eastern extreme of Fram Strait, is mainly affected by the northbound transport of water in the WSC. Mixing processes on the shelf result in Transformed Atlantic Water in the fjords, and the advection of Atlantic water also carries boreal fauna into the fjords. The phytoplankton production is about 80 g C m À2 yr À1 in Fram Strait, and has been estimated both below and above this for Kongsfjorden. The zooplankton fauna is diverse, but dominated in terms of biomass by calanoid copepods, particularly Calanus glacialis and C. finmarchicus. Other important copepods include C. hyperboreus, Metridia longa and the smaller, more numerous Pseudocalanus (P. minutus and P. acuspes), Microcalanus (M. pusillus and M. pygmaeus) and Oithona similis. The most important species of other taxa appear to be the amphipods Themisto libellula and T. abyssorum, the euphausiids Thysanoessa inermis and T. longicaudata and the chaetognaths Sagitta elegans and Eukrohnia hamata. A comparison between the open ocean of Fram Strait and the restricted fjord system of Kongsfjorden-Krossfjorden can be made within limitations. The same species tend to dominate, but the Fram Strait zooplankton fauna differs by the presence of meso-and bathypelagic copepods. The seasonal and inter-annual variation in zooplankton is described for Kongsfjorden based on the record during July 1996-2002. The ice macrofauna is much less diverse, consisting of a handful of amphipod species and the polar cod. The ice-associated biomass transport of ice-amphipods was calculated, based on the ice area transport, at about 3.55 · 10 6 ton wet weight per year or about 4.2 · 10 5 t C yr À1 . This represents a large energy input to the Greenland Sea, but also a drain on the core population residing in the multi-year pack ice (MYI) in the Arctic Ocean. A continuous habitat loss of MYI due to climate warming will likely reduce dramatically the sympagic food source. The pelagic and sympagic food web structures were revealed by stable isotopes. The carbon sources of particulate organic matter (POM), being Ice-POM and Pelagic-POM, revealed different isotopic signals in the organisms of the food web, and also provided information about the sympagic-pelagic and pelagic-benthic couplings. The marine food web and energy pathways were further determined by fatty acid trophic markers, which to a large extent supported the stable isotope picture of 0079-6611/$ -see front matter Ó the marine food web, although some discrepancies were noted, particularly with regard to predator-prey relationships of ctenophores and pteropods.

Recent studies of contaminants under the Canadian Northern Contaminants Program (NCP) have substantially enhanced our understanding of the pathways by which contaminants enter Canada's Arctic and move through terrestrial... more

Recent studies of contaminants under the Canadian Northern Contaminants Program (NCP) have substantially enhanced our understanding of the pathways by which contaminants enter Canada's Arctic and move through terrestrial and marine ecosystems there. Building on a previous review (Barrie et al., Arctic contaminants: sources, occurrence and pathways. Sci Total Environ 1992:1-74), we highlight new knowledge developed under the NCP on the sources, occurrence and pathways of contaminants (organochlorines, Hg, Pb and Cd, PAHs, artificial radionuclides). Starting from the global scale, we examine emission histories and sources for selected contaminants focussing especially on the organochlorines. Physical and chemical properties, transport processes in the environment (e.g. winds, currents, partitioning), and models are then used to identify, understand and illustrate the connection between the contaminant sources in industrial and agricultural regions to the south and the eventual arrival of contaminants in remote regions of the Arctic. Within the Arctic, we examine how contaminants impinge on marine and terrestrial pathways and how they are subsequently either removed to sinks or remain where they can enter the biosphere. As a way to focus this synthesis on key concerns of northern residents, a number of special topics are examined including: a mass balance for HCH and toxaphene (CHBs) in the Arctic Ocean; a comparison of PCB sources within Canada's Arctic (Dew Line Sites) with PCBs imported through long-range transport; an evaluation of concerns posed by three priority metals--Hg, Pb and Cd; an evaluation of the risks from artificial radionuclides in the ocean; a review of what is known about new-generation pesticides that are replacing the organochlorines; and a comparison of natural vs. anthropogenic sources of PAH in the Arctic. The research and syntheses provide compelling evidence for close connectivity between the global emission of contaminants from industrial and agricultural activities and the Arctic. For semi-volatile compounds that partition strongly into cold water (e.g. HCH) we have seen an inevitable loading of Arctic aquatic reservoirs. Drastic HCH emission reductions have been rapidly followed by reduced atmospheric burdens with the result that the major reservoir and transport agent has become the ocean. In the Arctic, it will take decades for the upper ocean to clear itself of HCH. For compounds that partition strongly onto particles, and for which the soil reservoir is most important (e.g. PCBs), we have seen a delay in their arrival in the Arctic and some fractionation toward more volatile compounds (e.g. lower-chlorinated PCBs). Despite banning the production of PCB in the 1970s, and despite decreases of PCBs in environmental compartments in temperate regions, the Arctic presently shows little evidence of reduced PCB loadings. We anticipate a delay in PCB reductions in the Arctic and environmental lifetimes measured in decades. Although artificial radionuclides have caused great concern due to their direct disposal on Russian Shelves, they are found to pose little threat to Canadian waters and, indeed, much of the radionuclide inventory can be explained as remnant global fallout, which was sharply curtailed in the 1960s, and waste emissions released under license by the European reprocessing plants. Although Cd poses a human dietary concern both for terrestrial and marine mammals, we find little evidence that Cd in marine systems has been impacted by human activities. There is evidence of contaminant Pb in the Arctic, but loadings appear presently to be decreasing due to source controls (e.g. removal of Pb from gasoline) in Europe and North America. Of the metals, Hg provokes the greatest concern; loadings appear to be increasing in the Arctic due to global human activities, but such loadings are not evenly distributed nor are the pathways by which they enter and move within the Arctic well understood.

Measurements of atmospheric turbulence made during the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) are used to examine the profile stability functions of momentum, ϕ m , and sensible heat, ϕ h , in the stably stratified... more

Measurements of atmospheric turbulence made during the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) are used to examine the profile stability functions of momentum, ϕ m , and sensible heat, ϕ h , in the stably stratified boundary layer over the Arctic pack ice. Turbulent fluxes and mean meteorological data that cover different surface conditions and a wide range of stability conditions were continuously measured and reported hourly at five levels on a 20-m main tower for 11 months. The comprehensive dataset collected during SHEBA allows studying ϕ m and ϕ h in detail and includes ample data for the very stable case. New parameterizations for ϕ m (ζ) and ϕ h (ζ) in stable conditions are proposed to describe the SHEBA data; these cover the entire range of the stability parameter ζ = z/L from neutral to very stable conditions, where L is the Obukhov length and z is the measurement height. In the limit of very strong stability, ϕ m follows a ζ 1/3 dependence, whereas ϕ h initially increases with increasing ζ , reaches a maximum at ζ ≈ 10, and then tends to

Chaetognaths are important members of Arctic mesozooplankton communities in terms of abundance and biomass. Despite this, the bulk of seasonal studies have focused on grazing copepods. Arctic chaetognaths comprise three major species... more

Chaetognaths are important members of Arctic mesozooplankton communities in terms of abundance and biomass. Despite this, the bulk of seasonal studies have focused on grazing copepods. Arctic chaetognaths comprise three major species which are thought to be strict carnivores: Eukrohnia hamata, Parasagitta elegans and Pseudosagitta maxima. This thesis uses datasets collected from plankton net sampling during five years in European, Canadian and Alaskan areas of the Arctic (2007, 2008, 2012, 2013, 2014) and includes a full annual cycle in the Canadian Arctic (2007-2008), the purpose being to improve our understanding of the distributions, life history and feeding strategies of E. hamata and P. elegans. The following topics are addressed: (1) the feeding strategy and maturity of P. elegans in the European Arctic during the polar night in 2012 and 2013; (2) the growth, breeding cycles, feeding strategies and vertical distributions of E. hamata and P. elegans, in the Canadian Arctic from 2007 to 2008; and (3) spatial differences in the feeding strategies of E. hamata and P. elegans in autumn 2014. To investigate feeding strategies, a combination of gut contents and biochemical techniques was used. In the Canadian Arctic, both E. hamata and P. elegans live for around 2 years. P. elegans mainly colonized epi-pelagic waters, whereas E. hamata mainly colonized meso-pelagic waters. In this region, P. elegans reproduced continuously from summer to early winter when copepod prey peak in near-surface waters. This is characteristic of income breeders. However, results for E. hamata revealed that this species spawned distinct and traceable broods during separate reproductive windows in both spring-summer and autumn-winter, suggesting capital breeding. Daily predation rates inferred from gut content analyses appeared to be generally low in the two chaetognath species, though inferred predation rates in summer-autumn exceeded those in winter-spring. Feeding studies revealed that E. hamata consumed particulate organic matter (possibly falling marine snow) throughout the year but especially in the summer, whereas P. elegans did not feed in this way. High summer growth seems to be a characteristic of both these species. Growth during winter was highly restricted in P. elegans, to a lesser extent in E. hamata. In summary, differences in how lipids and marine snow are utilised by the two species could explain differences in their breeding cycles and seasonal growth patterns.

An historical archive of over 25 000 radiosonde observations from the former Soviet "North Pole" series of drifting ice stations has been compiled and made available to interested researchers. This archive is the only long-term set of... more

An historical archive of over 25 000 radiosonde observations from the former Soviet "North Pole" series of drifting ice stations has been compiled and made available to interested researchers. This archive is the only long-term set of meteorological sounding data over the Arctic Ocean. The digital archive is a result of the multiyear, collaborative efforts of a group of United States and Russian scientists and keypunch operators working under the auspices of Working Group VIII, an area of study within the United States-Russian Federation Agreement for Protection of the Environment and Natural Resources. The archive contains soundings from 21 drifting stations over the period 1954-90 and is being distributed by the National Snow and Ice Data Center in Boulder, Colorado.

This paper is based on the premise that research into the environmental impact of continental flood basalt (CFB) volcanism has paid insufficient attention to the potential ecosystem damage that would result from the direct deposition of... more

This paper is based on the premise that research into the environmental impact of continental flood basalt (CFB) volcanism has paid insufficient attention to the potential ecosystem damage that would result from the direct deposition of hundreds of megatons (Tg) of sulphur and other volatiles. The environmental impacts of the 1783 Laki Fissure eruption are reviewed in outline. It is shown that in a relatively brief period of volcanic activity, volatiles emitted by the eruption damaged and destroyed vegetation from the Arctic Ocean to the Mediterranean. Air pollution was so intense that human health was affected and the national death rate increased dramatically in both England and France. It is proposed that the events of 1783 may be used as a paradigm for the environmental impacts of a CFB lava flow, and the emissions of 1783 are scaled up to illustrate this point. Thus, if a Laki style event were to erupt for a year it would approach the physical scale of a single episode of the Roza flow in the Columbia River CFB and potentially yield 576 Tg of sulphur gases which could have been oxidised into approximately 945 Tg of aerosol. This could generate a tropospheric aerosol mass of approximately 708 Tg H2SO4. The ecosystem impact of the deposition of acids on this scale would be profound and, as with the actual Laki event, be continental in scale. All parts of the plant life cycle would be disrupted, including photosynthesis and fruiting. Inevitably, withthe disruption of food webs animals would also be affected. Poorly buffered inland waters would be acidified, as would Boreal soils, reducing their biodiversity. In our already polluted and interdependent world, any future event on this scale would have serious consequences for human health and trade.

We propose to drill sediments appropriate for a detailed study of the Plio-Pleistocene evolution of millennial to Milanktovitch scale climatic oscillations in the Okhotsk and Bering Seas. Biological, chemical and physical oceanography as... more

We propose to drill sediments appropriate for a detailed study of the Plio-Pleistocene evolution of millennial to Milanktovitch scale climatic oscillations in the Okhotsk and Bering Seas. Biological, chemical and physical oceanography as well as adjacent continental climate of the Okhotsk and Bearing Seas are highly sensitive to global climate conditions, and are recorded by variations in the sedimentary composition

In this chapter, Timo Koivurova and Sébastien Duyck examine some key principles that could be used to sustainably address challenges in governing the Arctic Ocean. Significantly, as the first part of this chapter highlights, the... more

In this chapter, Timo Koivurova and Sébastien Duyck examine some key principles that could be used to sustainably address challenges in governing the Arctic Ocean. Significantly, as the first part of this chapter highlights, the environmental governance regime for the Arctic already clearly recognizes the legitimate expectations of and a role in decision-making for non-state actors, and in particular the indigenous peoples of the Arctic. As the authors make clear, future discussions in relation to the Arctic will focus on governance rather than on new treaties.

The chemical status of major and trace elements (TE) and organic carbon (OC) has been studied in the Severnaya Dvina and Pinega rivers draining granitic moraine, carbonate and sedimentary deposits of the Arkhangelsk region (NW Russia, the... more

The chemical status of major and trace elements (TE) and organic carbon (OC) has been studied in the Severnaya Dvina and Pinega rivers draining granitic moraine, carbonate and sedimentary deposits of the Arkhangelsk region (NW Russia, the White Sea basin of the Arctic Ocean). Sampling was performed during winter and summer baseflow seasons and during the spring flood (2007)(2008). Size separation procedure included on-site filtration through 5 μm, 0.22 μm, 100, 10 and 1 kDa, and dialysis through 1 kDa and 10 kDa pore-size membranes. The organic carbon concentration in "truly" dissolved form (b 1 kDa) does not depend on rock lithology or season, being on average equal to 5.0 ± 1.4 mg/L. Our observations may suggest the presence of two types of organic matter pool: i) allochtonous large-size colloids formed by lixiviation from upper soil horizons and ii) autochthonous (aquatic) small molecular-size substances, probably linked to bacterial and phytoplankton exudates. The total dissolved concentration of colloidal TE correlates with OC and Fe contents, being highest during the spring flood and lowest in winter time. There are two different patterns of TE colloidal status during different periods of the year, depending on their association with the organic or organo-mineral constituents of the colloidal matter pool. Trace and major element concentrations in the suspended matter of the River Severnaya Dvina were measured during different seasons over three years of observation. Based on collected data, we evaluate here, for the first time, the seasonal fluxes of major and trace elements in the suspended (N0.22 μm), total dissolved (b 0.22 μm) and colloidal (1 kDa-0.22 μm) forms. On an annual basis, there is a significant contribution (≥ 30%) of conventionally dissolved species (b 0.22 μm) to the overall flux of usually weakly mobile elements such as the divalent transition metals, Cd, Pb, V, Y, all REEs, Zr, Hf and Th. The transport of these insoluble elements occurs essentially in colloidal form. The spring flood occurring in May provides between 30 and 60% of the total annual dissolved and suspended flux of many insoluble trace elements (Fe, Co, Ni, Cr, Y, all REEs, Cd, Pb, Zr, Hf and Th). We argue that trace element fluxes in Arctic rivers are often characterized by a high proportion of total dissolved matter (b0.22 μm) compared to suspended particulates, due mostly to the large contribution of organically-bound colloidal forms.

A sediment record from the practically unknown southernmost part of the Lomonosov Ridge off North Greenland/Ellesmere Island has been studied. GreenICE core 10 encompasses marine isotope stages (MIS) 7-1 and reveals changing... more

A sediment record from the practically unknown southernmost part of the Lomonosov Ridge off North Greenland/Ellesmere Island has been studied. GreenICE core 10 encompasses marine isotope stages (MIS) 7-1 and reveals changing paleoceanographic conditions and land-ocean connections during the last two glacial-interglacial cycles. The isotope record of planktic foraminifera Neogloboquadrina pachyderma (s) show large similarities to other Arctic Ocean key records, supporting that the pattern reflect over-regional changes of the halocline structure. The relatively low δ 18 O values of subpolar foraminifera Turborotalita quinqueloba in the last interglacial unit support that the specimens represent local production, related to warm interglacial conditions and a reduced sea ice cover in the interior Arctic Ocean. Enhanced deposition of coarse ice-rafted debris took place during the MIS 8/7 transition, periods of MIS 6, MIS 6/5 transition, MIS 5d, MIS 4, and late MIS 3 (30-40 14 C kyr BP). In MIS 2, IRD flux was low in the area. The IRD contains detrital carbonate similar to other Amerasia Basin records. The occurrence of finegrained, calcite-rich detrital carbonate layers at glacial-interglacial transitions, seems unique to this area. We suggest that detrital carbonate was transported and deposited from nepheloid flows during deglaciations of Ellesmere Island, when the Atlantic Water boundary current along the continental margin was gaining strength.

This review investigates the fate and behaviour of endosulfan, a current-use organochlorine pesticide, in temperate environments and the Arctic. Usage data and patterns, physical-chemical properties, environmental partitioning and... more

This review investigates the fate and behaviour of endosulfan, a current-use organochlorine pesticide, in temperate environments and the Arctic. Usage data and patterns, physical-chemical properties, environmental partitioning and degradation, environmental levels, global distribution and temporal trends are evaluated and discussed in the context of criteria that designate a substance as a persistent organic pollutant. Endosulfan is one of the most abundant OC pesticides in the global atmosphere and is capable of undergoing long range transport to remote locations such as the Arctic. Degradation of the two isomers, αand β-endosulfan, does occur in temperate/tropical soil and aquatic systems, both by abiotic and biotic processes, although this is highly dependent on the prevailing environmental conditions. Endosulfan sulfate is the major metabolite and this recalcitrant compound has been detected in air and is present in remote mountain lake sediments, although in comparison to α-endosulfan, data for this compound in the wider environment are lacking. Temporal trends from ice/snow cores as well as mountain lake sediments reveal a marked increase in endosulfan accumulation from the 1980s onwards. Furthermore, unlike other 'legacy' OC pesticides, levels of α-endosulfan do not show a decline in atmospheric monitoring data, reflecting ongoing use of this pesticide in the northern hemisphere. Endosulfan is present at low concentrations (relative to the pesticide, lindane) in surface Arctic Ocean waters, with the atmosphere likely to be the major contemporary source. Residues of endosulfan have been detected in marine biota for different geographical regions of the Arctic, with higher bioaccumulation factors (N 10 3 -10 7 ) for zooplankton and various species of fish, compared to studies in warmer/temperate systems. Endosulfan is present in marine mammals, although there is uncertainty in the various Arctic biota datasets due to differences in analytical techniques. For some biota, biomagnification factors for α-endosulfan are N 1, notably from fish to seal, although there is a wide variability in values between the same species for different regions of the Arctic. There is little if any evidence of trophic magnification of α-endosulfan in well-defined marine foodwebs, with some evidence of bio-dilution at higher trophic levels, presumably due to increased metabolism. Endosulfan does fulfil several of the criteria under the UNEP Stockholm Convention for designation as a persistent organic pollutant. The αand β-isomer have similar physical-chemical properties and environmental behaviour to some of the obsolete organochlorine pesticides, although an assessment of their persistence and toxicity should be viewed alongside endosulfan sulfate, as 'Σendosulfan'. Persistence of 'Σendosulfan' coupled to ongoing use of endosulfan pesticides, will ensure continued long-range transport and contamination of remote environments.

The arctic tundra and boreal forest were once considered the last frontiers on earlh because of their vast expanses remote from agricultural land-use change and industrial development. These regions are now, however, experiencing... more

The arctic tundra and boreal forest were once considered the last frontiers on earlh because of their vast expanses remote from agricultural land-use change and industrial development. These regions are now, however, experiencing environmental and social changes that are as rapid as those occurring anywhere on eadh. This paper summarizes the role of northern regions in the global system and provides a blueprint for assessing the factors that govern their sensitivitv to social and environmental chanqe. ROLE OF ARCTIC TUNDRA AND BOREAL FOREST IN THE GLOBAL SYSTEM .,\rctic tundra and boreal fbrest occupy l5% ol'the ice-liee ter'rcstrial surlace. an area larger than either tropical or tempcrate lirre sts (I). 'f hcse northeln biomes pla1, a key role in the global climate s),stcn. particular'ly during times of climatic change. 'l hc global ualnring trend of the past L)entuf),(2) is amplified O Royal Swedish Acadcm)' of Sciences 2004 http:/ius.u.arnbio.kl a.se

The study of particulate organic matter (OM) in Arctic Ocean sediments from the late Cretaceous to the Eocene (IODP Expedition 302) has revealed detailed information about the aquatic/marine OM fluxes, biological sources, preservation and... more

The study of particulate organic matter (OM) in Arctic Ocean sediments from the late Cretaceous to the Eocene (IODP Expedition 302) has revealed detailed information about the aquatic/marine OM fluxes, biological sources, preservation and export of terrestrial material. Here, we present detailed data from maceral analysis, vitrinite reflectance measurements and organic geochemistry.

The Arctic Council, an intergovernmental forum of the eight Arctic states, is currently embarked on a comprehensive assessment of Arctic marine activity in the 21 st centurythe Arctic Marine Shipping Assessment (AMSA). One of the... more

The Arctic Council, an intergovernmental forum of the eight Arctic states, is currently embarked on a comprehensive assessment of Arctic marine activity in the 21 st centurythe Arctic Marine Shipping Assessment (AMSA). One of the challenges for the AMSA study team has been to identify the major uncertainties that will be central to shaping the future of Arctic marine use in 2020 and 2050. Using scenario planning, AMSA has identified two primary drivers and uncertainties: (A) Resources and trade; and, (B) Governance. Four scenario narratives have been developed with these two, key uncertainties as the framework elements. The main arguments focus on the fact the Arctic has experienced globalization early in the century and that the global maritime industry has already ventured into the Arctic Ocean. Marine access in the Arctic Ocean is also changing in unprecedented ways and the extraordinary transformation Arctic sea ice is undergoing -thinning, extent reduction, and a reduction in the area of multiyear ice in the central ocean -has significant implications for longer seasons of navigation. However, the high prices of global commodities such as oil, gas, and hard minerals (for example, copper, nickel and zinc) have generated high levels of demand for Arctic natural resources. The Arctic states are challenged by an overall lack of maritime infrastructure to adequately support current and future levels of Arctic marine operations; ports, communications, environmental monitoring, search & rescue, incident response, aids to navigation, and coastal charting, to name a few, require substantial and timely investment by the coastal states and marine operators. A second challenge is the ongoing development of an integrated system of rules and regulations governing Arctic navigation that will enhance marine safety and ensure marine environmental protection throughout the basin. These challenges will require historic levels of cooperation among the Arctic states and broad engagement with the many, non-Arctic stakeholders and actors within the global maritime industry.

Sediment proxy data from the Norwegian, Greenland, and Iceland seas (Nordic seas) are presented to evaluate surface water temperature (SST) differences between Holocene and Eemian times and to deduce from these data the particular mode of... more

Sediment proxy data from the Norwegian, Greenland, and Iceland seas (Nordic seas) are presented to evaluate surface water temperature (SST) differences between Holocene and Eemian times and to deduce from these data the particular mode of surface water circulation. Records from planktic foraminiferal assemblages, CaCO 3 content, oxygen isotopes of foraminifera, and iceberg-rafted debris form the main basis of interpretation. All results indicate for the Eemian comparatively cooler northern Nordic seas than for the Holocene due to a reduction in the northwardly flow of Atlantic surface water towards Fram Strait and the Arctic Ocean. Therefore, the cold polar water flow from the Arctic Ocean was less influencial in the southwestern Nordic seas during this time. As can be further deduced from the Eemian data, slightly higher Eemian SSTs are interpreted for the western Iceland Sea compared to the Norwegian Sea (ca. south of 70ºN). This Eemian situation is in contrast to the Holocene when the main mass of warmest Atlantic surface water flows along the Norwegian continental margin northwards and into the Arctic Ocean. Thus, a moderate northwardly decrease in SST is observed in the eastern Nordic seas for this time, causing a meridional transfer in ocean heat. Due to this distribution in SSTs the Holocene is dominated by a meridional circulation pattern. The interpretation of the Eemian data imply a dominantly zonal surface water circulation with a steep meridional gradient in SSTs.

2-D elastic finite element models of the recent stress field of Central Europe are built to evaluate the loads exerted on the continental boundary and the magnitude of tectonic stresses within the continental part of the plate. The models... more

2-D elastic finite element models of the recent stress field of Central Europe are built to evaluate the loads exerted on the continental boundary and the magnitude of tectonic stresses within the continental part of the plate. The models comprise 24 tectonic blocks (their stiffness is either constant throughout the model or varies from block to block), 16 fault zones and 12 geologically significant boundary segments. We have obtained a relatively unique balance of external tectonic forces by (1) careful adjustment of calculated stress directions and regimes to complex pattern of stress from data and (2) by calibration with gravitational potential energy. A high level of compression (ca.9 × 1012 N m−1) exerted to the short Ionian side of the Adriatic indenter is crucial for the stress-field pattern in Central Europe. The Adria microplate rotates due to eccentricity between the Africa push from the south and the Alpine buttress to the north. A free boundary of the Apennines does not contribute significantly to this motion. Kinematics of this indenter is controlled by friction on the Dinaric suture, which, in turn is decisive for strain-energy distribution between the Alpine and the Pannonian domains. The predicted pronounced extension in the Greece–Aegean segment (2.5 × 1012 N m−1) implies active pull transferred from the Hellenic subduction zone. This extension releases stress in the Balkan–Pannonian region and enables the eastward escape of tectonic blocks in front of advancing Adria. Significant changes of tectonic push trends are found along the Black Sea–Caucasus boundary segment and at the European passive margin from the North Sea to the Arctic Ocean. Differential stresses in Central Europe are estimated in the range of 10–60 MPa when averaged over the 30–80-km-thick mechanically heterogeneous lithosphere. The maximum stiffness contrast across the model is predicted to be of one order of magnitude. Apparent friction coefficients of fault zones differ between the North European part of the plate (0.4–0.7), the Pannonian region (0.15–0.25) and the Dinaric suture (0.55).

The ivory gull (Pagophila eburnea) is a seabird that inhabits Arctic oceans throughout the year, often in association with polar pack ice. It is rare (<14,000 breeding pairs globally) and remains one of the most poorly known seabird... more

The ivory gull (Pagophila eburnea) is a seabird that inhabits Arctic oceans throughout the year, often in association with polar pack ice. It is rare (<14,000 breeding pairs globally) and remains one of the most poorly known seabird species in the world. Canada supports breeding populations of international significance, and residents of communities in the Canadian High Arctic currently observe fewer ivory gulls than they did in the 1980s. However, no population trend data existed for this species in Canada prior to this study. We initiated aerial surveys in July 2002 and 2003 of most known ivory gull colonies in Canada to assess current population levels. Forty two colonies were visited, 14 of which were new discoveries. We recorded an 80% decline in numbers of nesting ivory gulls. Several of the largest known colonies were completely extirpated and those that remained supported significantly fewer nesting birds than previously observed. Results were similar in both years despite some differences in local sea ice conditions, suggesting a numerical decline in the population and not simply annual fluctuations in colony occupation. Declines have occurred in all habitat types and across the known Canadian breeding range, suggesting that causes of the decline may be related to factors occurring during migration or on wintering grounds. We recommend that international efforts now be directed at assessing population status and trends of this species in other circumpolar countries. Crown

The effects of climate change are leading to pronounced physical and ecological changes in the Arctic Marginal Ice Zone (MIZ). These are not only of concern for the research community but also for the tourism industry dependent on this... more

The effects of climate change are leading to pronounced physical and ecological changes in the Arctic Marginal Ice Zone (MIZ). These are not only of concern for the research community but also for the tourism industry dependent on this unique marine ecosystem. Tourists increasingly become aware that the Arctic as we know it may disappear due to several environmental threats, and want to visit the region before it becomes irrevocably changed. However, 'last-chance tourism' in this region faces several challenges. The lack of infrastructure and appropriate search and rescue policies are examples of existing issues in such a remote location. Additionally, tourism itself may further amplify the physical and ecological changes in the Arctic region. In this article, we provide an interdisciplinary analysis of the links between the MIZ, climate change and the tourism industry. We also identify existing regulations and the need for new ones concerning operations in the MIZ and in the Arctic Ocean. ARTICLE HISTORY

1] Regarded as one of the world's most productive marine environments, the Bering Sea is widely thought to be rapidly warming and losing sea ice. Such changes would be expected to have dramatic impacts on primary producers, with cascading... more

1] Regarded as one of the world's most productive marine environments, the Bering Sea is widely thought to be rapidly warming and losing sea ice. Such changes would be expected to have dramatic impacts on primary producers, with cascading effects on upper trophic levels, including this region's vast commercial fisheries resources. Here, we use satellite-derived sea ice concentration, sea surface temperature, and ocean color data as input to a primary productivity algorithm to take stock of environmental change and primary production in the Bering Sea. Results show that, rather than declining, mean annual sea ice extent in the Bering Sea has exhibited no significant change over the satellite sea ice record . Furthermore, significant warming during the satellite sea surface temperature record is mainly limited to the summer months, when all regions of the Bering Sea warmed. This warming suggests increasing stratification during the phytoplankton growth season. Despite certain hot spots of primary production and a strong pulse in the spring, the rate of annual area-normalized primary production in the Bering Sea (124 g C m −2 yr −1 ) is below the global mean (140 g C m −2 yr −1 ). Between 1998 and 2007, basin-wide annual primary production ranged from 233 to 331 Tg C yr −1 under the influence of highly variable sea ice and temperature conditions. By comparing warm, low-ice years (2001)(2002)(2003)(2004)(2005) with cold, high-ice years (1998-2000 and 2006-2007), we speculate that Bering Sea primary productivity is likely to rise under conditions of future warming and sea ice loss.