West Coast Of Greenland Research Articles

The Chatanika and Sondrestrom Radars – a brief history

Abstract. The Sondrestrom upper atmospheric research facility, located just north of the Arctic Circle near the west coast of Greenland, will soon celebrate 30 yr of operations. The centerpiece of the facility, an incoherent scatter radar, has collected 46 000 h of data on the ionospheric state parameters. This instrument was designed and built to measure the effects of nuclear bombs on radio wave propagation in the South Pacific, but instead was deployed to Alaska to study the effects of auroral structuring on the ionosphere, and was later moved to Greenland to explore the auroral cusp and the dynamics of the polar cap boundary. This is the story of the birth and genesis of the instrument, its travels, and the evolution of its facility.

Effects of acute temperature changes on gut physiology in two species of sculpin from the west coast of Greenland

For a fish to thrive, the gut must function efficiently. This is achieved through a range of processes, including controlled patterns of gut motility and modifications in gut blood flow. The knowledge of how gut functions in fish are affected by environmental temperature is sparse, and in order to understand how changes in climate may affect fish populations, we need to understand how gut blood flow and gut motility are affected by changes in temperature. By simultaneous recording of gut blood flow, gut motility, cardiac output, heart rate and cardiac stroke volume, in vivo at 4, 9 and 14 °C, the acute thermal sensitivity of a thermal generalist (shorthorn sculpin Myoxocephalu scorpius) was compared to the more strictly Arctic species (Arctic sculpin M. scorpioides). Temperature effects on gut motility were further explored in vitro, using isolated smooth muscles. Elevated water temperatures increased gut blood flow and contractile activity. Contraction frequency increased nearly threefold and gut blood flow almost doubled with the 10 °C increase. Both cardiac output and heart rate increased with temperature, while cardiac stroke volume decreased. The cholinergic agonist carbachol was most potent on smooth muscles at 9 °C. There were no differences between the two species, suggesting that the gastrointestinal and cardiovascular systems of Arctic sculpin, although a more pronounced Arctic species, have similar abilities to cope with acute fluctuations in water temperature as shorthorn sculpin. The impact of increased gut activity at higher temperatures needs further investigation before the effects of climate change can be predicted.

The Significance of the North Water Polynya to Arctic Top Predators

The North Water polynya (~76°N to 79°N and 70°W to 80°W) is known to be an important habitat for several species of marine mammals and sea birds. For millennia, it has provided the basis for subsistence hunting and human presence in the northernmost part of Baffin Bay. The abundance of air-breathing top predators also represents a potential source of nutrient cycling that maintains primary production. In this study, aerial surveys conducted in 2009 and 2010 were used for the first time to map the distribution and estimate the abundance of top predators during spring in the North Water. Belugas (Delphinapterus leucas) were not detected north of 77°20'N but were found along the coast of West Greenland and offshore in the middle of the North Water with an abundance estimated at 2245 (95% CI 1811-2783). Narwhals (Monodon monoceros) were widely distributed on the eastern side of the North Water with an estimate of abundance of 7726 (3761-15870). Walruses (Odobenus rosmarus) were found across the North Water over both shallow and deep (>500m) water with an estimated abundance of 1499 (1077-2087). Bearded (Erignathus barbatus) and ringed seals (Phoca hispida) used the large floes of ice in the southeastern part of the North Water for hauling out. Most polar bears (Ursus maritimus) were detected in the southern part of the polynya. The abundances of bearded and ringed seals were 6016 (3322-10893) and 9529 (5460-16632), respectively, and that of polar bears was 60 (12-292). Three sea bird species were distributed along the Greenland coast (eiders, Somateria spp.), in leads and cracks close to the Greenland coast (little auks, Alle alle) or widely in open water (thick-billed guillemots, Uria lomvia).

Brief communication "Historical glacier length changes in West Greenland"

Abstract. Past glacier fluctuations provide insight into glacier dynamics, climate change, and the contribution of glaciers to sea-level rise. Here, the length fluctuations since the 19th century of 18 local glaciers in West and South Greenland are presented, extending and updating the study by Weidick (1968). The studied glaciers all showed an overall retreat with an average of 1.2 ± 0.2 km over the 20th century, indicating a general rise of the equilibrium line along the west coast of Greenland during the last century. Furthermore, the average rate of retreat was largest in the first half of the 20th century.

Recent warming in Greenland in a long-term instrumental (1881–2012) climatic context: I. Evaluation of surface air temperature records

We present an updated analysis of monthly means of daily mean, minimum and maximum surface air temperature (SAT) data from Greenland coastal weather stations and from a long-running site on the Greenland ice sheet, and analyse these data for evidence of climate change, especially focusing on the last 20 years but using the whole periods of available records (some since 1873). We demonstrate very strong recent warming along the west coast of Greenland, especially during winter (locally >10 °C since 1991), and rather weaker warming on the east Greenland coast, which is influenced by different oceanographic/sea-ice and meteorological synoptic forcing conditions to the rest of Greenland. Coastal Greenland seasonal mean SAT trends were generally 2–6 °C, strongest in winter (5.7 °C) and least in summer and autumn (both 2.2 °C), during 1981–2011/12. Since 2001 Greenland mean coastal SAT increased significantly by 2.9 °C in winter and 0.8 °C in summer but decreased insignificantly by 1.1 °C in autumn and 0.2 °C in spring, during a period when there was little net change (≤ ± 0.1 °C) in northern hemisphere temperatures. SAT means for the latest 2001–11/12 decade were significantly in excess of those for peak decadal periods during the Early Twentieth Century Warm Period only in summer and winter, and not significantly greater in spring and autumn. Summer SAT increases in southern Greenland for the last 20 years were generally greater for maximum than minimum temperatures. By contrast, in winter, the recent warming was greater for minimum than maximum temperatures. The greatest SAT changes in all seasons are seen on Greenland’s west coast. SAT changes on the ice sheet and a key marginal glacier closely followed nearby coastal temperatures over the last 20 years.

Spatial and temporal variations in Greenland glacial‐earthquake activity, 1993–2010

Glacial earthquakes are anomalous earthquakes associated with large ice‐loss events occurring at marine‐terminating glaciers, primarily in Greenland. They are detectable teleseismically, and a proper understanding of the source mechanism may provide a remote‐sensing tool to complement glaciological observations of these large outlet glaciers. We model teleseismic surface‐wave waveforms to obtain locations and centroid–single‐force source parameters for 121 glacial earthquakes occurring in Greenland during the period 2006–2010. We combine these results with those obtained by previous workers to analyze spatial and temporal trends in glacial‐earthquake occurrence over the 18‐year period from 1993–2010. We also examine earthquake occurrence at six individual glaciers, comparing the earthquake record to independently obtained observations of glacier change. Our findings confirm the inference that glacial‐earthquake seismogenesis occurs through the capsize of large, newly calved icebergs. We find a close correspondence between episodes of glacier retreat, thinning, and acceleration and the timing of glacial earthquakes, and document the northward progression of glacial earthquakes on Greenland's west coast over the 18‐year observing period. Our results also show that glacial earthquakes occur when the termini of the source glaciers are very close to the glacier grounding line, i.e., when the glaciers are grounded or nearly grounded.

Molecular phylogeny and toxin profiles of Alexandrium tamarense (Lebour) Balech (Dinophyceae) from the west coast of Greenland

Detection of paralytic shellfish poisoning (PSP) toxins in scallops from the west coast of Greenland exceeding the 800μg toxin/kg shellfish limit led to an investigation with the aim of finding the responsible organism(s). Three strains of Alexandrium Halim were established from single cell isolations. Morphological identification of the strains and determination of their position within the genus by LSU rDNA sequences was carried out. Light microscopy revealed that the three strains was of the Alexandrium tamarense morphotype, and bayesian and neighbor-joining analyses of the LSU rDNA sequences placed them within Group I of the A. tamarense species complex. The toxicity and toxin profiles of the strains were measured by liquid chromatography fluorescence detection (LC-FD) and their identity was confirmed by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). The three strains all turned out to be toxic and all produced large proportions (>60% total mol) of gonyautoxins 1 and 4 (GTX1/GTX4). This is the first record of saxitoxin producers from western Greenland. The toxin profiles were atypical for A. tamarense in their absence of N-sulfocarbanoyl C1/C2 or B1/B2 toxins. Rather the high molar percentage of GTX1/GTX4, the lesser amounts of only carbamoyl toxins and the absence of decarbamoyl derivatives are more characteristic features of A. minutum strains. This may indicate that the genetically determined toxin profiles in Alexandrium species are more complex than previously appreciated.

Feeding ecology of capelin (Mallotus villosus Müller) in West Greenland waters

Capelin (Mallotus villosus Muller) is a key pelagic mediator of energy from lower to higher trophic levels in arctic waters. This is also the case in Greenland waters, but little is known of its feeding behaviour in this region. By analysing stable nitrogen isotopes and stomach content of capelin collected along 1500 km of the Greenland west coast, this study aims to provide knowledge on capelin feeding ecology and the role that diet composition and biomass may have in generating the observed latitudinal growth differences in Greenland capelin. In total, 572 stomachs were sampled. The most dominant prey by wet weight was euphausiids (61 %) followed by amphipods (18 %) and copepods (10 %). The most common species were Thysanoessa raschii, Themisto libulla, Calanus finmarchicus and Calanus hyperboreus. Copepods dominated in smaller capelin but were replaced by euphausiids in larger fish. A similar prey shift towards euphausiids along with an increase in prey weight (relative and absolute) was seen with increasing latitude. The spatial variation in feeding pattern was supported by stable nitrogen analyses. The mean δ15N values of capelin muscle tissue for the south (60–64°N) and north (68–72°N) were 9.54 ‰ ± 0.72 and 12.47 ‰ ± 0.38 (mean ± SD), respectively. However, when differences in isotopic baseline values (C. finmarchicus δ15N, 2.47 ‰) in the two areas were taken into account, the isotope values suggest that capelin in the northern areas fed on a slightly higher trophic level higher than in the south, as would be expected with increasing importance of euphausiids. These significant feeding differences along the Greenland west coast are likely impacting capelin growth and condition as they show parallel trends along the same gradient.

Distribution and biological characteristics of Atlantic salmon (Salmo salar) at Greenland based on the analysis of historical tag recoveries

Abstract Reddin, D. G., Hansen, L. P., Bakkestuen, V., Russell, I., White, J., Potter, E. C. E., Dempson, J. B., Sheehan, T. F., Ó Maoiléidigh, N., Smith, G. W., Isaksson, A., Jacobsen, J. A., Fowler, M., Mork, K. A., and Amiro, P. 2012. Distribution and biological characteristics of Atlantic salmon (Salmo salar) at Greenland based on the analysis of historical tag recoveries. – ICES Journal of Marine Science, 69: 1589–1597. In this study, we examined 5481 records of tag recoveries at Greenland from a new tagging database held by ICES that contains information on salmon tagged in Canada, France, Faroes, Greenland, Iceland, Ireland, Norway, Spain, the UK (Northern Ireland, Scotland, England, and Wales), and the United States from the early 1960s to the present. For 4806 of the tag recoveries, latitude and longitude information were available, describing, to varying degrees of accuracy, the location of recovery of tagged fish. Release and recovery dates were variable, but no significant differences over time were noted. The information derived from tag recoveries was used to describe the distribution and growth of salmon of different origins. The proportion of recoveries from East Greenland suggested that potential multi-sea-winter salmon from northern Europe have a more easterly distribution than those from southern Europe. The location of recovery of salmon of North American origin differed from that of European salmon along the west coast of Greenland. Tag recoveries by country were not uniformly distributed across the respective NAFO Divisions. Tags from salmon originating in Canada and the United States were more commonly recovered in northern locations than tags from European-origin salmon. Analysis of rates of tag recovery suggested similar rates before and after the introduction of the NASCO Tag Return Incentive Scheme. The straight-line migration speed of both North American and European salmon changed very little over the time-series, but was ∼40% greater for North American salmon (0.43 m s−1) than for European salmon (0.29–0.32 m s−1).

Myxobolus groenlandicus n. sp. (Myxozoa) distorting skeletal structures and musculature of Greenland halibut Reinhardtius hippoglossoides (Teleostei: Pleuronectidae)

A specimen of Greenland halibut Reinhardtius hippoglossoides (Walbaum, 1792) caught on the west coast of Greenland (Qasigiannguit) was found to possess serious pathological changes in the body musculature. A series of cartilaginous cylindrical structures organized symmetrically at the position of the proximal pterygiophores had changed the musculature and produced irreversible distortions (cavities and holes) in the fillet of the processed fish, leaving it with no value for the industry. Histopathological investigation showed that these structures consisted of hypertrophic cartilage containing numerous myxospore-producing plasmodia. Morphometric and molecular analyses of the parasites showed that both spore morphology and rDNA sequences complied with characteristics of the genus Myxobolus, but no full affiliation with a known species could be found. The parasite is a previously undescribed species, and the name Myxobolus groenlandicus n. sp. is assigned to this new myxobolid.

Local contamination in relation to population genetic diversity and resilience of an arctic marine amphipod

The objective of this study was to investigate whether populations inhabiting a contaminated environment are affected in terms of decreased genetic diversity due to selection of tolerant genotypes and if such effect carries a cost. Marine arctic amphipod populations (Orchomenella pinguis) were collected from sites within a contaminated fjord, as well as from sites outside the fjord on the west-coast of Greenland over three years (2006–2008). Impacts on genetic diversity, effects on resilience such as development of tolerance and cost were determined. AFLP-analysis was used to explore within and between population genetic diversity, and exposure studies were performed where the populations were subjected to known and unknown stressors to assess resilience. Populations collected at three contaminated sites all had reduced genetic diversity in 2007 compared to populations outside the fjord. This pattern was different in 2008 as all contaminated site populations increased in diversity, whereas a decrease in diversity occurred at the outer sites. However, tolerance, but even more so, cost, was related to contamination exposure in 2008, in spite of the shift in genetic diversity. We suggest that contamination rapidly induces effects that can be captured as tolerance and associated cost, whereas effects on genetic diversity can be difficult to separate from recent migration events that dilute eventual decreases in diversity due to contamination pressure. As long as impacted populations can be influenced by migration events that increase the genetic diversity and add health to an affected population, populations in contaminated areas may have enhanced probability of survival.

Bitumen biomarkers in the Mid-Proterozoic Ilímaussaq intrusion, Southwest Greenland – A challenge to the mantle gas theory

GC and GC/MS/MS analysis on rock extracts has shown that the bitumen in the peralkaline Ilímaussaq intrusion, previously assumed to be abiogenic, is biotic in origin. A biotic origin is in accordance with previously published stable carbon isotopic data on bituminous matter in the rocks. The biomarker distribution in the bitumen, including the less common bicadinanes, resembles that of oil seeps on the central West Greenland coast 2200 km farther north, whose source rocks and migration history are relatively well established. We use a recent re-construction of the subsidence and later exhumation of the West Greenland coastal region during the Mesozoic-Cenozoic ( Japsen et al., 2006a, b) to anticipate that hydrocarbons migrated from deeper parts of the basin offshore west of Greenland. The rocks of Ilímaussaq were probably more deeply invaded than the surrounding granites due to their higher proportion of corroded minerals, which may explain why bitumen has not been observed elsewhere in the area. Hydrocarbon gases (C1–C5) present in fluid inclusions were also analysed, after having been released by treatment with hydrochloric acid that resulted in an almost complete disintegration of the Ilímaussaq intrusion rocks. The acid extraction method proved generally more efficient than the crushing procedure applied by others, but gave similar results for the chemical composition of the gas (CH 4: 88–97%) and isotopic ratios (δ 13 C CH 4 : −1.6 to −5.0‰; δ 13 C C 2 H 6 : −9.2 to −12.5‰), with the exception of hydrocarbons hosted in quartz, which showed significantly lower isotopic values for methane ( Graser et al., 2008). Previous researchers have suggested an abiotic origin for these hydrocarbon gases, but we suggest a biotic origin for the majority of them, not just those in quartz, assuming that the isotopic ratio of the constituents have changed due to loss of gas by diffusion. The assumption of gas loss via diffusion is supported by published studies on micro-fissures in minerals typical of the Ilímaussaq and field investigations showing diffusive loss of gas from the peralkaline Khibina and Lovozero massifs on the Kola Peninsula, Russia, which are, in many respects of mineralogy and hydrocarbon content, similar to the Ilímaussaq intrusion. Both the hydrocarbon gases and bitumen in the Khibina and Lovozero massifs have been cited as prime examples of a deep mantle source, although the carbon isotopic ratio of the bitumen clearly pointed to an organic origin. The trends in carbon isotopic ratio of methane released with time from freshly exposed rocks also supports our hypothesis of 13C enrichment of the methane remaining within the rock. Thus, there is good evidence that the hydrocarbons in the Kola alkaline massifs are mostly biotic in origin, in which case the probability of finding economic hydrocarbon accumulations from a deep mantle source seems exceedingly small.

Assessing the Roles of Three Eddy Types in Restratifying the Labrador Sea after Deep Convection

Abstract Restratification after deep convection is one of the key factors in determining the temporal variability of dense water formation in the Labrador Sea. In the subsurface, it is primarily governed by lateral buoyancy fluxes during early spring. The roles of three different eddy types in this process are assessed using an idealized model of the Labrador Sea that simulates the restratification season. The first eddy type, warm-core Irminger rings, is shed from the boundary current along the west coast of Greenland. All along the coastline, the boundary current forms boundary current eddies. The third type, convective eddies, arises directly around the convection area. In the model, the latter two eddy types are together responsible for replenishing 30% of the winter heat loss within 6 months. Irminger rings add another 45% to this number. The authors’ results thus confirm that the presence of Irminger rings is essential for a realistic amount of restratification in this area. The model results are compared to observations using theoretical estimates of restratification time scales derived for the three eddy types. The time scales are also used to explain contradicting conclusions in previous studies on their respective roles.

Glaciologist studies Greenland snow conditions and helps calibrate CryoSat instrument

GREENLAND—On a typically frigid mid‐July day at Summit Station, almost smack in the middle of Greenland, with the temperature hovering around −10°C, Elizabeth Morris and John Sweeny were bundled up against the cold atop their black Ski‐Doo snowmobiles, which Morris described as being similar to motorcycles on ski tracks. They drove the vehicles—without yet attaching three wooden sleds that would be pulled during their summer scientific traverse across part of central Greenland—on a practice spin along the perimeter of Summit's groomed, approximately 4600‐meter × 60‐meter snow runway. One of the longest runways in the world, it lies atop 3.2 kilometers of ice, with the horizon stretching in every direction. Morris, a glaciologist who is a senior associate at the Scott Polar Research Institute at Cambridge University, United Kingdom, and Sweeny, her polar guide, were taking advantage of an unexpected extra day at Summit, a scientific research station sponsored by the U.S. National Science Foundation (NSF), before the traverse began. They hoped that the socked‐in visibility just a few hours earlier that morning, 16 July, would not be repeated the following day so that a U.S. Air National Guard 109th Airlift Wing C‐130 cargo plane would be cleared to fly to Summit from Kangerlussuaq on Greenland's west coast with needed supplies. Morris and Sweeny would load up each sled with about 270 kilograms of gear.

Fjords help to melt calving fronts on tidal glaciers

The Greenland ice sheet is connected to the ocean through outlet glaciers that are in direct contact with the ocean. As global temperatures increase, many of these glaciers—particularly on Greenland's west coast—are melting at rates higher than those at which ice accumulates. This melting is typically attributed to rising temperatures of the West Greenland Current, which bathes the continental shelf. However, this assertion is based mostly on inference; remote conditions in Greenland, coupled with a lack of direct records of glacial behavior or seawater properties where the glacier meets the ocean, hinder studies that could pinpoint exactly how the glaciers are losing ice.

Detecting ice-sheet melt area over western Greenland using MODIS and AMSR-E data for the summer periods of 2002–2006

We present the results from two independent approaches for monitoring ice-sheet melt area over western Greenland. The microwave-based cross-polarization gradient ratio (XPGR) approach (Abdalati, W. and Steffen, K., 1995, Detecting ice-sheet melt area over western Greenland using MODIS and AMSR-E data for the summer periods of 2002–2006. Geophysical Research Letter, 22, pp. 787–790) is compared with a newly developed technique that exploits reflectance characteristics of snow/ice using near-infrared and visible wavelengths, to assess the extent of ice-sheet melt area over the west coast of Greenland. Data from the moderate resolution imaging spectroradiometer (MODIS) sensor onboard the National Aeronautics and Space Administration's (NASA) Earth Observing Satellite (EOS) Terra are analysed through the years 2002–2006 to monitor melt area extent between May and September. Concurrently, the XPGR ratio is derived from advanced microwave scanning radiometer (AMSR-E) data to develop a comparative measure of melt area over the same period of investigation. Although the techniques represent fundamentally different physical approaches, good agreement is observed between these distinct melt area products. The enhanced spatial resolution that is achieved from the MODIS sensor offers additional insight into the melt response over the course of the summer melt period and highlights the advantage of synthesizing diverse sensors and retrieval algorithms for Earth observation.

Toxin production and temperature-induced morphological variation of the diatom Pseudo-nitzschia seriata from the Arctic

This is the first record of a domoic acid-producing organism from polar waters. Strains of the cold-water diatom Pseudo-nitzschia seriata were isolated from water samples collected from the west coast of Greenland. Growth experiments on two of the strains showed similar growth rates at 4 °C and production of DA (domoic acid) and the two isomers IA (isodomoic acid A) and IB (isodomoic acid B). Both strains produced significantly higher amounts of DA than of IA and IB. The concentrations of domoic acids were 1.46–1.93 pg per cell, and thus have the potential to pose a risk for amnesic shellfish poisoning. Four strains of P. seriata were cultured at different temperatures (4, 10 and 15 °C), and morphological differences were found at the different temperatures. Similar differences have been observed previously in field samples from different geographical areas and have resulted in uncertainty regarding the taxonomy of P. seriata and related species. Transmission electron microscopy showed that at 4 °C the strains corresponded to the original description of P. seriata. At higher temperatures, the number of rows of poroids in the striae as well as the density of poroids decreased, and cells then resembled the closely related P. australis. The Greenlandic strains of P. seriata did not grow well at 15 °C. The identity of the strains was confirmed by analyses of ITS1, 5.8S and ITS2 rDNA from P. seriata and P. australis, using strains from different geographical areas. There was a close phylogenetic relationship between P. seriata and P. australis but the analyses demonstrated consistent molecular differences between the two species, in spite of the morphological similarity.

The interannual variability of the surface eddy kinetic energy in the Labrador Sea

The variability of the surface eddy kinetic energy (EKE) in the Labrador Sea is investigated with a suite of numerical integrations using a regional ocean model. Simulations are performed over the period 1980–2001 and are compared to satellite observations over the last 9 years. The surface EKE pattern in the basin is dominated by a region along the West coast of Greenland where eddies, mainly anticyclonic, are formed by instability of the main currents flowing over the continental slope, consistent with previous idealized results. Here the interannual changes are linked to the shear of the incoming boundary current system imposed as boundary condition to the model domain. The highly variable strength of the East Greenland current at the northeast boundary, derived from the Simple Ocean Data Assimilation (SODA) reanalysis, strongly influences the vortex formation. In the center of the Labrador Sea, where deep convection occurs, a statistically significant portion of the modeled interannual surface EKE variability is correlated with the local atmospheric forcing, and both heat and wind fluxes play an important role and can be adopted as predictors at a lag of 2–3 months. The Arctic Oscillation index can also be used as a remote indicator of the atmospheric fluxes, but with lower skill than local measurements. In contrast the North Atlantic Oscillation index does not correlate significantly with the surface EKE at intraseasonal and interannual scales. The analysis of altimeter data over the 1993–2001 supports the existence of this asymmetry between the regime locally forced by the atmosphere in the central basin, and the regime remotely forced by the incoming boundary current along the west Greenland coast. Those results have important implications for monitoring and predicting the surface eddy kinetic energy variability in the Labrador Sea.

Heat sources for glacial melt in a sub-Arctic fjord (Godthåbsfjord) in contact with the Greenland Ice Sheet

[1] Recent warming of Subpolar Mode Water off Greenland has been suggested to accelerate the mass loss from tidal outlet glaciers of the Greenland Ice Sheet. We present a comprehensive analysis of water masses, dynamics, and interannual hydrographic variability in Godthåbsfjord, a sill fjord in contact with tidal outlet glaciers on the west coast of Greenland. Through seasonal observations we recognize an intermediate baroclinic circulation mode driven by tidal currents and an associated important local heat source for the fjord. During summer this results in significant warming and freshening of the intermediate layer of the main fjord, and the increase in heat content is equivalent to melting of ∼2.1 km3 of glacial ice. This is comparable to ∼8 km3 glacial ice discharge estimated from the Kangiata Nunâta Sermia calving front per year. During winter the external heat source in the West Greenland Current enters the fjord as intermittent inflows of either cold (<2°C) or warm (>2°C) dense water in pulses of 1 to 3 months duration. Four distinct circulation modes are observed in the fjord, of which all can contribute to glacial ice melt. An important aspect of the ice distribution in the fjord is that only a minor fraction is exported out of the fjord.

Hematodinium sp. (Alveolata, Syndinea) detected in marine decapod crustaceans from waters of Denmark and Greenland

Five decapod crustacean species were examined for presence of the parasitic dinoflagellate Hematodinium spp. (Alveolata, Syndinea) by morphological methods (colour and pleopod methods) as well as by PCR and nested PCR with Hematodinium-specific primers. Nephrops norvegicus, Pagurus bernhardus and Liocarcinus depurator were sampled by trawling in Danish waters and Chionoecetes opilio and Hyas araneus were sampled by trapping off the west coast of Greenland. The existence of Hematodinium has not previoiusly been documented in Danish waters, but it was detected in all 3 decapod species examined in the present study. Hematodinium sp. was also detected for the first time in H. araneus and the existence of Hematodinium sp. in Greenlandic C. opilio was documented by PCR. Analyses of 26 Hematodinium sp. ITS1 sequences, including sequences from all 5 host species sampled, revealed more than 95% sequence similarity between 24 of the sequences. Two Hematodinium sp. ITS1 sequences from C. opilio were only 81% similar to the 24 other ITS1 sequences. The nested PCR approach resulted in the highest reported percentages of positive samples for Hematodinium sp.in the hosts investigated (between 45 and 87.5%). However, no decapods were found to be infected with Hematodinium sp. based on morphological methods. Consequently, Hematodinium sp. may be more common than previously believed, and, assuming that the DNA found originated from viable and infectious parasite cells, infections may not always be fatal. We suggest that the hosts investigated may have been subject to latent infections that could develop into a fatal disease only if the hosts were physiologically stressed due to other factors.