Northeast Water Polynya Research Articles

Biodiversity of peracarid crustaceans(Malacostraca) from the shelf downto the deep Arctic Ocean

During three expeditions with the RVs Meteor and Polarstern more than sixty thousand peracarids were sampled from the deep Arctic Ocean (northern North Atlantic) by means of an epibenthic sledge. Sampling areas were the Kolbeinsey Ridge north of Iceland (800–1100 m), the Northeast Water Polynya, off Greenland (45–517m), and 75°N east of Greenland (197–2681m). Until now 288 species of Peracarida have been identified to species level. These 288 species comprise 152 genera and 59 families of Amphipoda, Cumacea, Isopoda, Mysidacea and Tanaidacea. Thirty-eight genera were very frequent and were sampled at each expedition (these were 22 species of Isopoda, seven species of Cumacea, three species of Amphipoda and Mysidacea, each, and two species of Tanaidacea). Sixty genera are eurybathic, occurring at least over a depth range of 1000m, some even from the shelf up to 2681m depth. Only 10 genera are stenobathic, occurring only in the deep sea. No significant decrease in species number with depth or latitude could be observed. The influencing factors probably causing different community structures are diverse, ranging from food availability over substrate or hydrographical qualities to interspecific competition.

The coastal edge of the Northeast Water polynya in spring 1993

Multidisciplinary, marine ecological observations were conducted at the shallow water edge of the Northeast Water in June, 1993. Although variable in size and shape, a small polynya was constantly present at Eskimonaes, at the fast-ice edge of Ingolfsfjord. A shallow stratified layer developed at the water sufface at negative water and air temperatures—an effect of sea ice melting in cold water early in the season. Nutrients were recorded in considerable quantities, although by mid July NO3 had become depleted. The chlorophyll and phytoplankton maxima at 8–12 m depth had peak values of 2 mg chl a m−3, typical for Arctic algal blooms. The phytoplankton included over 90 species and was dominated by the Fragillariopsis group. Zooplankton was poor in biomass and density, but over 23 taxa were found, with the copepods Oithona similis and Pseudocalanus acuspes being numerically dominant. Sedimentation was approximately 0.2 g dry weight m−2 d−1 and suspended matter concentrations ranged from 4 to 19 mg l−1. The benthos was represented by hard bottom forms only, with a surprisingly dense cover of macrophytes. Juvenile sea urchins (Strongylocentrotus droebachiensis), brittle stars (Ophiocten sericeum) and amphipods were dominant. Higher trophic levels were represented by benthic feeders, such as eiders and walruses. The area observed was more similar to high Arctic fjord ecosystems than to the offshore central Northeast Water polynya.

Seasonal variability of sediment trap collections in the Northeast Water polynya. Part 1: sea-ice parameters and particle flux

Vertical particle flux was recorded in the Northeast Water polynya (NEW) by means of moored time series sediment traps from August 1992 to July 1993. Traps were deployed with USCGC Polar Sea at four positions in a trough of the polynya. The recorded annual flux varied between 4.2–9.8 g/m 2 at 130 m and 26–33 g/m 2 at 50 m above the sea bottom. The amount of settling particles in the NEW is controlled to a high degree by the ice regime (e.g., total ice concentration, variability, ice type fraction, snow and the melt period) due to its impact on the production of primary formed particles. By using passive microwave satellite data from the Special Sensor Microwave/Imager, it was possible to relate particle flux with total ice concentration and its changes on short (several days) and long term scales for individual sampling periods. In combination with the dry weight of the collected particles, it is possible to examine the relation of ice parameters and its impact on the sedimenting processes in the NEW. Of particular interest is the correlation of three sedimenting periods associated with ice formation in the fall, the effect of the winter polynya based on new ice formation, and the melt period.

Species of Thaumatomastix (Thaumatomastigidae, Protista incertae sedis) from the Arctic sea ice biota (North-East Water Polynya, NE Greenland)

The sea ice biota of polar regions contains numerous heterotrophic flagellates very few of which have been properly identified. The whole mount technique for transmission electron microscopy enables the identification of loricate and scaly forms. A survey of Arctic ice samples (North-East Water Polynya, NE Greenland) revealed the presence of ca. 12 taxa belonging to the phagotrophic genus Thaumatomastix (Protista incertae sedis). Species of Thaumatomastix possess siliceous body scales and one naked and one scale-covered flagellum. The presence in both Arctic samples and sea ice material previously examined from the Antarctic indicates that this genus is most likely ubiquitous in polar sea ice and may be an important component in sea ice biota microbial activities.

Biosynthesis of macromolecular and lipid classes by phytoplankton in the Northeast Water Polynya

Biosynthesis of macromolecular and lipid classes by phytoplankton in the Northeast Water Polynya

Seabirds utilizing the Northeast Water polynya

A small seabird community depends on the resources of the Northeast Water (NEW) polynya. In spring, at least 1000 King Eiders and 2500 Common Eiders form pre-breeding congregations at Ob Bank before dispersing in mid June to breeding areas. The most abundant species is the Fulmar, which breeds in six colonies with a total of 2550 “apparently occupied sites”, corresponding to approx. 1475 active pairs in 1993. Kittiwakes occupied almost 900 sites at Mallemukfjeld, with an estimated 733 breeding pairs. The entire NEW area probably holds 400–500 pairs of Ivory Gulls, and about 500 individuals were associated with a colony on Henrik Krøyer Holme; this is one of the world's largest known colonies. Sabine's Gulls breed at the same islands and on Kilen (approx. 50 pairs in each place). Small colonies (total less than 1000 birds) of Arctic Terns are distributed along the edge of the polynya, with the largest colony of about 100 pairs on Henrik Krøyer Holme. The Black Guillemot is the only breeding auk species (< 20 pairs) in the area. Small numbers of Red Phalaropes were observed in the polynya in 1992 and 1993, and the species may have bred at Henrik Krøyer Holme in 1993; the polynya area may also serve as a staging area for transpolar migrants. In late summer a few hundreds of Ross's Gull—non-breeding adults and immatures—show up in and around the polynya, and in recent years a few cases of breeding have also been recorded. The relatively small seabird populations are evidence of a generally low carrying capacity of the polynya area. Apart from the benthic foraging eiders and the Black Guillemot, the seabird community of NEW consists of surface feeders—Fulmars and gulls—dependent on small fish and zooplankton. During their stay in the NEW area, the five most abundant surface feeders will annually consume approximately 243,000 kg (wet weight) of food, of which the Fulmars alone take 67%. Food demand in relation to area of open water in the polynya is highest in spring (approx. 0.2 kg/km 2 ), which is

The prehistory of the coastal areas of Amdrup Land and Holm Land adjacent to the Northeast Water polynya: an archaeological perspective

Abstract The prehistory of the coastal areas of Amdrup Land and Holm Land adjacent to the Northeast Water polynya are introduced using the archaeological results obtained during fieldwork in 1993. Human occupation during the last 4,500 years in the area can be divided into three periods, of which the last two are well documented while the first is less well represented. Data presented in the paper are used in correlating human occupations in the area during these periods with the presence of the polynya.

A summary of the formation and seasonal progression of the Northeast Water Polynya

Abstract A summary of the seasonal development of the Northeast Water Polynya ice cover characteristics is presented. This is based primarily on satellite remote sensing observations, with some in situ measurements, including both new and published data.

Present and past vegetation in the high arctic, easternmost North Greenland and the relation to the Northeast Water Polynya

Abstract The extremely poor polar desert vegetation of a coastal belt along the polynya on Sophus Muller Nœs is described and compared with the richer vegetation of Amdrup Land approximately 30 km from the coast. A new delimitation of the polar deserts in Greenland is proposed. A core from the bottom of a lake in Amdrup Land gives evidence of an early Holocene period warmer than today.

Neogloboquadrina pachyderma (sinistral coiling) as paleoceanographic tracers in polar oceans: Evidence from northeast water polynya plankton tows, sediment traps, and surface sediments

The abundance and chemistry of the planktonic foraminifera Neogloboquadrina pachyderma (sinistral coiling) have long been used as tools for monitoring polar surface ocean changes and for correlating these changes to atmospheric and thermohaline circulation fluctuations. However, due to its remote habitat, very little is known about how modern N. pachyderma (s.) respond to changing environmental conditions in the polar seas. Modern samples of N. pachyderma (s.) from the Northeast Water Polynya provide a means for studying how environmental conditions affect the vertical distribution and chemistry of this species. Highest abundances of N. pachyderma (s.) were associated with the chlorophyll maximum in the surface 20–80 m, where they are exploiting their primary food source. Evidence suggests that the addition of a calcite crust modifies the calcite tests of some N. pachyderma (s.) between 50 and 200 m, increasing shell density and modifying shell chemistry. The shell mass of encrusted forms is 3–4 times greater than the nonencrusted forms between 50 and 200 m. The oxygen isotope composition of N. pachyderma (s.) shells increase by 1.5‰ in response to local water column gradients. The δ13C values of N. pachyderma (s.) are basically invariant with depth in this region, are consistently 1.0‰ depleted in comparison with the δ13C for equilibrium calcite, and remain basically constant during the shell‐thickening process. Mass balance calculations suggest that encrustation occurs at all depths, but abundance counts suggest that the process occurs mostly at the depth of the main pycnocline. Sediment fluxes of N. pachyderma (s.) occur during a 2‐week bloom event and decrease to almost zero below complete ice cover. The decoupling of the processes controlling abundances and shell chemistry explain the discrepancies between transfer function and isotopically derived paleotemperature estimates of surface conditions, in some oceanic settings. The ability of δ18O to record surface ocean conditions will depend on vertical water column gradients, as evidenced by the differences in core‐top calibrations between the North and South Atlantic.

Feeding success and survivorship of Arctic cod larvae, Boreogadus saida, in the Northeast Water polynya (Greenland Sea)*

ABSTRACTWe tested the hypothesis that enhanced feeding success and survivorship of Arctic cod larvae in the Northeast Water polynya (Greenland Sea) are associated with high densities of their zooplankton prey in areas of low sea ice concentration. From late May to early August 1993, first‐feeding yolk‐sac larvae (6.5–8.5 mm long) were collected primarily along the coast and over shallow banks in the polynya, whereas post yolk‐sac larvae (8.5–14 mm) were more uniformly dispersed over the sampling area. Arctic cod larvae &lt; 14 mm fed almost exclusively on copepod nauplii (74% of total prey number) and copepod eggs (16%). Feeding success was defined as the residuals of the regression of the number of prey ingested against larval length. Nauplii density varied from 9600 to 731300 nauplii m‐2(equivalent to 0.16 to 12.2 nauplii 1‐1) but, contrary to our hypothesis, seldom limited the feeding success of Arctic cod larvae. Water temperature was the best predictor of feeding success in larvae of all sizes. First‐feeding success and survivorship were low for larvae hatched before mid‐July, and improved thereafter as surface temperatures increased in the open waters of the polynya. There was no relationship between feeding success and irradiance or wind. Assuming a fixed spawning season, it is concluded that a larger fraction of the newly hatched larvae would experience adequate temperatures in years when the polynya opens early. Based on this conclusion, we propose that the timing of the opening of polynyas is a critical determinant of year‐ class strength in Arctic cod, a key species in the Arctic food web.

The species composition of the Peracarid fauna (Crustacea, Malacostraca) of the Northeast Water Polynya (Greenland)

The species composition of Crustacea, Peracarida was investigated over a period of almost three months in the Northeast Water Polynya (NEW) off Greenland. Samples were collected in May - July 1993 during the Polarstern expedition ARK IX/2-3 using an epibenthic sledge. Within the macrobenthos on the shelf, peracarids were an important component, besides polychaetes, molluscs and brittle stars. At 22 stations in depths from 45-517 m, about 38 000 specimens were identified and have been listed.&#x0D; In total, 229 species belonging to 51 families, and 121 genera were found. Seven species assemblages were characterized: the "deep assemblage", the "shallow assemblage", the "Westwind Trough assemblage", the "Norske Trough assemblage", the "common species assemblage", the "high-accumulation area assemblage", and the "ice-associate assemblage". Differences in abundance and composition do not primarily reflect bathymetric gradients, but more the availability of food (phytoplankton, more importantly ice algae incorporation into the sediment) and therefore the temporal and spatial opening of the polynya. It is suggested that primary production, hydrography, and ice conditions (lateral advection due to the anticyclonic gyre around Belgica Bank, and upwelling at a southern fast-ice extension) are the main factors influencing the peracarid crustacean community.

Size-differential regimes of phytoplankton production in the Northeast Water Polynya (77*-81*N)

Size-differential regimes of phytoplankton production in the Northeast Water Polynya (77*-81*N)

Peracarid Crustaceans (Malacostraca) From a "Time-Series Station" in the Westwind Trough of the New-Polynya (Greenland): a Benthic Response To Productivity?

AbstractDuring the expedition ARK IX-2/3 with RV "Polarstern" to the Northeast Water Polynya (NEW-Polynya), off Greenland, a station in the Westwind Trough was revisited sever times. Successful samples were taken by means of a box corer seven times over 2 months (May-July 1993) and by an epibenthic sledge (EBS) five times over a period of six weeks. One-hundred-and-thirty-one species from 78 genera and 40 families comprising a total of 13 280 individuals were collected with the EBS. The most abundant taxon at this station were the Cumacea. Amphipoda were most diverse. A change in peracarid composition and abundance occurred between the stations sampled over the two months, especially in the box corer samples. For seven isopod species developmental stages were determined and compared. Although no clear difference in stage composition of the species investigated was observed between stations, within some species the number of immature, preparatory, and ovigerous females was high. This might indicate an active period of reproduction during early summer, during times of favourable food supply. High abundance of Peracarida was found shortly after a sedimentation event of chlorophyll (phytoplankton and ice algae), observed in the upper sediment layer, possibly reflecting a benthic response to productivity.

Amphipoda from northeast Greenland: a new genus and two new species (Crustacea: Peracarida)

During a cruise with the RV Polarstern to the North East Water Polynya, off north-east Greenland, 130 species of Amphipoda (Crustacea) were collected with an epibenthic sledge. Of these, two are new taxa which are described here: a new genus and species of the family Epimeriidae, Spindlerella groenlandica gen. et sp. nov., and a new species of the Odiidae, Imbrexodius polarsterni sp. nov. The new species have been sampled in the Northern and the Westwind Troughs in depths between 178 and 330 m.

North-East Water polynya: satellite observations summer 1992 and 1993

Abstract Polynyas in the Arctic have recently attracted much attention with studies of their geophysics (including water movements, heat flux and carbon dioxide flux) and their biology (including all phases from plankton over benthos to marine mammals and polar birds). A programme of remote sensing was undertaken in connection with two cruises by research vessels in the North-East Water polynya at the north-east corner of Greenland. Data from the Advanced Very High Resolution Radiometer (AVHRR) instrument on the NOAA satellites and Synthetic Aperture Radar (SAR) on ERS–1 was used supported by ground information collected by the research vessel, USCGC Polar Sea. The observations made are reported with examples of special events that control the state of the polynya. Based on repeated observations of floes the motion pattern is determined, for 1992 by means of AVHRR and for 1993 by ERS–l SAR. They confirm the anti-cyclonic movement around the Belgica Bank supported by a system of troughs surrounding the Ban...

Satellite tracking of high-arctic northern fulmars

Three northern fulmars (Fulmarus glacialis) were tracked with satellite transmitters while they dispersed from a colony at the North East Water polynya in high-arctic Greenland after breeding failure. The longest cumulative distance recorded was 2043 km in 14 days, giving an average daily movement of 143 km, and the maximum distance covered in 1 day was 369 km. The highest effective flight (ground) speed recorded was 25.8 kmh−1, and when corrected for non-linear flight path the ground speeds ranged between 27.9 and 38.4 kmh−1, which is very close to the theoretical most energy efficient airspeed (Vmp) of approximately 36 kmh−1. Bird flight tracks generally followed ice edges, and on long flights the birds used tail or cross winds. Within areas believed to be foraging areas birds moved cumulative distances of 86–488 km, or 33–147 kmday−1. While in the high-arctic, the birds appeared to select foraging areas mainly in the marginal ice zones, but all birds left the polynya following breeding failure and moved towards boreal waters. One bird was tracked to the polar front zone near Bear Island where an international fishing fleet operated. The study suggests that when the birds were no longer attached to the North East Water polynya by a breeding attempt, they sought alternative foraging grounds. Satellite transmitters or other devices were tested on a total of eight birds' (including the three tracked individuals), all of which probably failed in their breeding attempt. The birds' reactions to the handling and tagging are presented, and the possible reasons for the breeding failure discussed.

The Northeast Water Polynya as an atmospheric CO2 sink: A seasonal rectification hypothesis

During the multidisciplinary ‘NEW92’ cruise of the United States Coast Guard Cutter (USCGC) Polar Sea to the recurrent Northeast Water (NEW) Polynya (77–81°N, 6–17°W; July–August 1992), total dissolved inorganic carbon and total alkalinity in the water column were measured with high precision to determine the quantitative impact of biological processes on the regional air‐sea flux of carbon. Biological processes depleted the total inorganic carbon of summer surface waters by up to 2 mol C m−2 or about 3%. On a regional basis this depletion correlated with depth‐integrated values of chlorophyll a, particulate organic carbon, and the inorganic nitrogen deficit. Replacement of this carbon through exchange with the atmosphere was stalled owing to the low wind speeds during the month of the cruise, although model calculations indicate that the depletion could be replenished by a few weeks of strong winds before ice forms in the autumn. These measurements and observations allowed formulation of a new hypothesis whereby seasonally ice‐covered regions like the NEW Polynya promote a unique biologically and physically mediated “rectification” of the typical (ice free, low latitude) seasonal cycle of air‐sea CO2 flux. The resulting carbon sink is consistent with other productivity estimates and represents an export of biologically cycled carbon either to local sediments or offshore. If this scenario is representative of seasonally ice‐covered Arctic shelves, then the rectification process could provide a small, negative feedback to excess atmospheric CO2.

Primary productivity and new production in the Northeast Water (Greenland) Polynya during summer 1992

The primary productivity and rates of new production were assessed in the Northeast Water Polynya during July–August 1992 by using 14C and 15N tracer techniques. The average rate of primary production for the entire region, including an approximate correction for the effects of ice cover, was 0.21 g C m−2 d−1, with the maximum observed rate being slightly over 1.1 g C m−2 d−1. Rates of new production (uncorrected for effects of ice cover) averaged 3.08 mmol N m−2 d−1. Surface f ratios (the ratio between nitrate uptake and the total inorganic nitrate uptake) averaged 0.63, and depth‐integrated f ratios equaled 0.69. It appeared that the water column in general was bilayered, in that f ratios were reduced near the surface in low (less than 2 μM) nitrate waters and increased deeper in the euphotic zone. Ammonium concentrations and uptake were consistently low throughout the region. Growth rates were modest, with surface growth rates averaging 0.33 per day. A simple relationship among the attenuation of solar radiation by sea ice (and its associated snow cover and microbial community), the percentage of open water, ice thickness, water column attenuation, and phytoplankton photosynthesis is described. The relationship is nonlinear, but, in general, nutrient‐replete water column photosynthesis are largely a function of the percentage of open water rather than ice thickness. Both irradiance and nutrient fields exert strong influences on phytoplankton productivity and ultimately result in a mosaic of biomass within the polynya.

Measurements of the summer surface heat budget of the Northeast Water Polynya in 1992

A research cruise of the United States Coast Guard Cutter Polar Sea to the Northeast Water Polynya (NEWP), off the eastern coast of Greenland (77–81°N, 6–17°W), was made from mid‐July to mid‐August of 1992 (NEWP '92) as the first field component of the multidisciplinary study of a high‐Arctic polynya. Instruments to measure the components of the surface heat budget of the polynya were installed on a foremast at the bow of the ship. Measurements of apparent wind speed and direction, air temperature and humidity, long‐ and short‐wave downwelling radiation were made, together with sea surface temperature. The surface heat budget of the polynya derived from these measurements is presented and is shown to be dominated by the net radiation, with a mean value of 133 W m−2, when calculated over the duration of the cruise. The short‐wave insolation was high during the days with clear skies, reaching over 500 W m−2 at noon and dropping to about 75 W m−2 during the sunlit, polar night, with a mean value of 197 W m−2. In comparison, the mean value of the incident long‐wave radiation is 267 W m−2. In general, the turbulent fluxes were negligible. The measured heat budget is compatible with the observed thermal structure in the surface layers of the polynya and the presumed ice melt during the summer season.