Arctic Greenland Research Articles

Rebuilding the Stock of Northeast Arctic Greenland Halibut (Reinhardtius hippoglossoides)

After the absence of 1989–1994 year classes of Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides) in regular surveys, an annual survey programme was initiated in 1996 to map juveniles in previously unsurveyed waters north and east of Svalbard. After rather stable juvenile indices in the first years, the recruitment indices have increased tenfold from 2001 to 2006. The increase in juvenile Northeast Arctic (NEA) Greenland halibut corresponded with an increase in spawning stock biomass. The swept area abundance estimates of spawning females (i.e., females >60 cm), has nearly tripled since 1996 having achieved 29 000 t in recent years. This improvement occurred after years of strong regulations, introduced in 1992, by enforcing a moratorium on the targeted offshore fishery and strict bycatch regulations for the species. Regulations were introduced after a dramatic change in stock status for the NEA Greenland halibut during the 1980s. Females >75 cm contributed more to the stock’s total egg production (TEP) in more recent years. The contribution from these larger females increased from 10% of the TEP estimate in 1996 to 21% in 2006. The results from the present study indicate that rebuilding Greenland halibut stocks takes time, and that at least 12–15 years with restrictions are needed to recover from the low levels observed in the Barents Sea in the beginning of the 1990s.

The isolation of Atlantic cod, Gadus morhua (Gadiformes), populations in Northern Meromictic lakes—A recurrent arctic phenomenon

Although it has previously been considered to be a rare phenomenon, this paper provides evidence of eight occurrences of Atlantic cod in northern coastal saline lakes in Arctic Canada, Greenland, Norway, and Russia. Historic and current habitat features that are necessary for Atlantic cod to colonize and persist in Arctic meromictic lakes are discussed. Data analyses confirm that the persistence of Atlantic cod in Arctic lakes is a recurrent phenomenon, and these populations represent an important component of intraspecific biodiversity.

Depth-related changes in the arctic epibenthic megafaunal assemblages of Kangerdlugssuaq, East Greenland

The effects of depth-related differences in environmental factors (pressure, hydrography, habitat and disturbance) on the benthic megafauna at the mouth of Kangerdlugssuaq Fjord in Arctic Greenland were investigated using a towed camera platform and autonomous underwater vehicle photographs. Large reductions in faunal density (60,132 to 1881 individuals ha−1) and increases in diversity (H′=0.93–2.54), through increases in richness (ES(220)=7.6–18.8) and reductions in dominance (Berger–Parker index=0.77–0.38) were found between 270 and 720 m water depth. Assemblages were separated into distinct shallow, intermediate and deep faunas by multivariate community analysis. In the shallower sites there were high levels of iceberg disturbance, directly reducing diversity as well as creating a complex, patchy environment inhabited by high densities of mobile suspension-feeding epifauna. In the deeper areas there was small-scale disturbance from the deposition of drop stones, but at a relatively low frequency and magnitude, which allowed increased species diversity. Proportions of deposit-feeding epifaunal and infaunal taxa rose with depth, as indicated by an increase with depth in faunal traces. Decreases in faunal density probably resulted from decreased food supply with depth.

Spectral measures and mixed models as valuable tools for investigating controls on land surface phenology in high arctic Greenland

BackgroundChanges in land surface phenology are of major importance to the understanding of the impact of recent and future climate changes in the Arctic. This paper presents an extensive study from Zackenberg Ecological Research Operations (ZERO) where snow melt, climate and growing season characteristics of six major high arctic vegetation types has been monitored during 1999 to 2005. We investigate the growth dynamics for dry, mesic and wet types using hand held measurements of far red normalised difference vegetation index (NDVI-FR) and generalized additive mixed models (GAMM).ResultsSnow melt and temperature are of major importance for the timing of the maximum growth as well as for the seasonal growth. More than 85% of the variance in timing of the maximum growth is explained by the models and similar for the seasonal growth of mesic and wet vegetation types. We find several non-linear growth responses to the environmental variables.ConclusionWe conclude that the uses of GAMMs are valuable for investigating growth dynamics in the Arctic. Contrary to several other studies in the Arctic we found a significant decreasing trend of the seasonally integrated NDVI-FR (SINDVI) in some vegetation types. This indicates that although greening might occur wide-spread in the Arctic there are variations on the local scale that might influence the regional trends on the longer term.

Radical past climatic changes in the Arctic Ocean and a geophysical signature of the Lomonosov Ridge north of Greenland

The Arctic Ocean is a landlocked basin, at present covered by perennial sea ice. During the past few decades a significant thinning and shrinking of the sea ice has been observed, and modelling studies indicate that the Arctic Ocean ice cover could, by the end of this century, almost disappear from most parts of the Arctic Ocean during peak summer seasons. It remains uncertain, however, whether the environmental changes are an enhanced greenhouse-warming signal or a result of natural (long-term) variability, but palaeoceanographic studies can contribute to our understanding of the natural variability of environmental parameters, e.g. sea-ice cover and oceanographic changes on time-scales of centuries to millennia. As part of the multidisciplinary EU project Greenland Arctic Shelf Ice and Climate Experiment (GreenICE), sediment coring and seismic reflection measurements have been undertaken in a hitherto unexplored part of the Arctic Ocean, the margin of the Lomonosov Ridge in the Lincoln Sea (Fig. 1). The aim of the project was to study the structure and dynamics of the sea-ice cover and attempt to relate these to longer-term records of climate variability retrieved from sediment cores. The main field work was carried out in May 2004 from an ice camp established by a Twin Otter aircraft on drifting sea ice at 85°N, 65°W, c. 170 km north of Alert, Arctic Canada. The camp was deployed over the shallowest part of the Lomonosov Ridge off the northern Greenland/Canada continental margin (Fig. 1). The sea-ice drift would normally be between east and south, but persistent easterly winds resulted in a fast drift trajectory towards the WSW, such that the camp drifted a distance of approximately 62 km during the two weeks camp period. At present the study area is heavily ice covered, and forecast models of future shrinking Arctic sea-ice cover suggest that this area is one of the least sensitive to warming in the Arctic. The results obtained from the GreenICE project challenge this view.

Differences in food abundance cause inter-annual variation in the breeding phenology of High Arctic waders

Previous work has shown that High Arctic waders in Greenland are “income breeders”, i.e. the resources used for egg formation are based almost entirely on biomass obtained on the breeding grounds. Thus, their breeding phenology is expected to be highly sensitive to inter-annual variation in food abundance during the pre-laying period. Early spring snow-cover may also influence timing of egg-laying either directly or mediated through food resources. Here, we report on the inter-annual variation in clutch initiation of three wader species breeding in High Arctic Greenland, Sanderling (Calidris alba), Dunlin (Calidris alpina) and Ruddy Turnstone (Arenaria interpres), in relation to spring snow-cover and spring arthropod abundance over ten breeding seasons at Zackenberg Research Station 1995–2005. Food abundance had the strongest effect on timing of clutch initiation, while the proportion of snow-free land had a weaker but still significant effect, i.e. more food and more snow-free land both result in earlier egg-laying. We hypothesize that food is most important when there is sufficient snow-free land to nest on, while snow-cover is of increasing importance in years with late snowmelt.

Functional and numerical responses of four lemming predators in high arctic Greenland

The high‐arctic tundra ecosystem has the world's simplest vertebrate predator–prey community, with only four predators preying upon one rodent species, the collared lemming (Dicrostonyx groenlandicus). We document the functional and numerical responses of all the four predators in NE Greenland. Using these data, we assess the impact of predation on the dynamics of the collared lemming with a 4 yr cycle and >100‐fold difference between maximum and minimum densities. All predator species feed mostly (>90%) on lemmings when lemming density is >1 ha−1, but the shapes of the predators’ responses vary greatly. The snowy owl (Nyctea scandiaca) is present and breeds only when lemming densities at snowmelt are >2 ha−1, giving rise to a step‐like numerical response. The long‐tailed skua (Stercorarius longicaudus) has a type III functional response and shifts from alternate food (mainly berries and insects) to lemmings with increasing lemming density. The skua surpasses all the other predators in summer by its total response. The type III functional response of the Arctic fox (Alopex lagopus) starts to increase at much lower lemming densities than the responses of the avian predators, but it has only a weak numerical response. Finally, the stoat (Mustela erminea) is the most specialized predator and the only one with a clearly delayed numerical response. According to their specific functional and numerical responses, each predator plays a key role at some point of the lemming cycle, but only the stoat has the potential to drive the lemming cycle. Stoat predation is greatly reduced in the winter preceding the lemming peak, and it reaches a maximum in the winter preceding the lowest lemming summer density. Stoat predation appears to maintain low lemming densities for at least two successive years. Our study provides empirical support for the specialist predator hypothesis about small mammal population cycles.

Epilithic Lichen Communities in High Arctic Greenland: Physical, Environmental, and Geological Aspects of Their Ecology in Inglefield Land (78°–79°N)

The present investigation of High Arctic epilithic lichens and their substrate is based on field observations in Inglefield Land, North-West Greenland, mainly in 1999, with subsidiary observations from 1995. Eighteen rock samples, all glacial erratics, were specifically selected on the basis of macroscopic mineralization features such as iron and copper staining, vein and breccia structures, and ore minerals. The samples are representative of the crystalline shield, and their lithologies can be matched with exposures in Inglefield Land. Seven lichen communities are recognized, viz. Pleopsidium chlorophanum c., Xanthoria elegans var. splendens c., Dimelaena oreina–Physcia caesia–Xanthoria elegans c., Xanthoria elegans–Umbilicaria virginis c., Orphniospora moriopsis c., Porpidia flavicunda c., and Tremolecia atrata c. The studied material on the 18 samples reveals no conspicuous correlation between metal concentrations in the rock samples and the lichen communities and, broadly speaking, it can be stated that the lichens reflect more the properties of the rock surface, such as, for example, nitrogen- and iron-bearing weathering crusts, than the mineralogical composition of the rocks. However, there is a very close affinity between the Orphniospora moriopsis community and one variety of syenitic rocks with elevated magnetite and phosphorus.

Vision and its Relationship to Novel Behaviour in St. Lawrence River Greenland Sharks, <em>Somniosus microcephalus</em>

Rarely observed Greenland Sharks, Somniosus microcephalus, were recorded at shallow depths by divers employing underwater video in the St. Lawrence River, in association with a seasonal concentration of Capelin (Mallotus villosus) in May-June 2003. We recorded unique proximity-induced display motor patterns in these sharks, which have not been recorded in underwater observations of Arctic Greenland Sharks. Arctic sharks have a high incidence of blindness due to an ocular copepod parasite, Ommatokoita elongata. The absence of parasite-induced blindness in St. Lawrence Greenland Sharks, in contrast to endemic blindness in the Arctic population, may allow sharks in this region to more readily visually recognize the presence of conspecifics and potential prey. Improved visual acuity may therefore allow St. Lawrence River sharks to express a different behavioural repertoire than Arctic sharks, with resulting changes in intra- and inter-specific aggression and predatory behaviour.

Egg size and reproductive adaptations among Arctic deep-sea copepods (Calanoida, Paraeuchaeta)

Reproductive strategies of the four congeneric and sympatric calanoid copepods Paraeuchaeta glacialis, P. norvegica, P. barbata, and P. polaris were studied in the Arctic Greenland Sea. Females of all species produce egg sacs and carry their brood attached to the genital opening until the offspring hatch. However, egg size and lipid content as well as clutch size and the fraction of females carrying egg masses show characteristic differences among the four species. P. glacialis and P. norvegica produce large numbers (37 to more than 50) of relatively small eggs, whereas P. barbata and P. polaris rely on small numbers (10 to 19 and 4 to 6, respectively) of large eggs with a high energy content. There is no correlation between female body size and egg size or clutch size, respectively. Females of the smallest species, P. polaris, produce relatively large eggs and show the highest energetic investment per egg. In contrast, energetic investment per clutch is highest in P. glacialis. Reproductive adaptations appear to be strongly related to the depth range inhabited by the respective species. In the central Greenland Sea P. glacialis and P. norvegica occur in the epipelagial and upper mesopelagial, whereas the other two species inhabit lower mesopelagic to bathypelagic depths. Thus, egg size increases with depth of occurrence, whereas clutch size is inversely correlated with depth. This observation leads to the hypothesis that the evolution of large eggs in deep-sea copepods may enable hatchlings to rely on a lecithotrophic development and thus represents a successful adaptation to cope with the limited food supply at great depths, whereas high offspring numbers in epipelagic species compensate for higher predation risks in the euphotic zone.

The Northernmost Ruins of the Globe: Eigil Knuth's Archaeological Investigations in Peary Land and Adjacent Areas of High Arctic Greenland, by Bjarne Grønnow and Jens Fog Jensen

The Northernmost Ruins of the Globe: Eigil Knuth's Archaeological Investigations in Peary Land and Adjacent Areas of High Arctic Greenland, by Bjarne Grønnow and Jens Fog Jensen

The northernmost ruins of the globe. Eigil Knuth's archaeological investigations in Peary Land and adjacent areas of High Arctic Greenland

An important part of the heritage of Count Eigil Knuth (1903-1996) is his archaeological archive including contextual information on prehistoric sites gathered during six decades of research in High Arctic Greenland. The finds and observations are a key to the understanding of human life under extreme conditions in a long-term perspective and represent a unique piece of evidence concerning the early cultural history of the Eastern Arctic. Knuth’s expeditions from 1932 to 1995 took him to Greenland and Canada, in particular High Arctic Greenland. In a number of important articles Knuth published the findings dating back to the earliest human settlement in Greenland. However, he never managed to present the complete body of information and results from his many investigations. The present authors have thus compiled a computer database based on his archive, and this has formed the starting point of the present book. The book focuses on Knuth’s most substantial contribution to archaeology: the prehistory of Peary Land and adjacent areas. In the catalogue emphasis has been placed on topographical and architectural information, site structure, artefact statistics and radiocarbon dates. A total of 154 archaeological sites are presented. 51 sites with a total of 244 features are Independence I sites (c. 2460-1860 cal. BC), 23 sites with a total of 416 features belong to Independence II (c. 900-400 cal. BC) and 63 sites with a total of 626 features are of Thule origin (c. 1400-1500 cal. AD). It has not been our ambition to re-analyse the finds or add new empirical data in connection with the production of this book. We do, however, present some new information on the faunal material from Peary Land based at Christyann Darwent’s recent analyses as well as new data on the dwelling features on the Adam C. Knuth Site, which was visited by a multidisciplinary team in 2001. The book is provided with an introduction presenting an overview and evaluation of Knuth’s remarkable curriculum vitae as an independent arctic archaeologist. In the concluding chapters some basic statistics on the archaeological sites are presented. We evaluate Knuth’s radiocarbon dates for of the Independence I, Independence II and Thule cultures in High Arctic Greenland, and settlement distributions and settlement patterns for the three cultures represented in Peary Land are discussed.

Comparing survey and assessment data: Consequences for stock evaluation of Northeast Arctic Greenland halibut

Based on VPA-estimates of abundance, survey data and commercial catch statistics of Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides Walbaum), the paper describes trends by year-class and age in the distribution of Greenland halibut between surveyed and not-surveyed areas. Changes in the distribution of I-group around 1990 to areas beyond the Svalbard surveys has previously been described and related to temperature changes in the Spitsbergen Current. This paper shows that this displaced distribution of the 1989-94 year-classes persisted up to age 7. The results indicate that the displacement was an extraordinary situation and other similar distribution shifts have not occurred during the last 30 years or more. Further, the shift co-occurred with extreme levels of the 137 year long time series of the index of the North-Atlantic Oscillation (NAO). The results are discussed in relation to stock management and climate change.

Changes in aspects of students' self-reported personal, social and technical skills during a six-week wilderness expedition in Arctic Greenland

This investigation focuses on students' self-reported changes in personal, social and technical skills that took place during a six-week long expedition to East Greenland. A 105-item pre-and post-expedition questionnaire was completed by 60 young expeditioners aged 16 to 20. Before the expedition participants generally felt that they had high levels of skills and were well prepared for the expedition. Of the 49 items in the 105-item questionnaire which related to participants' personal, social and technical skills, 22 showed statistically significant differences from those expected by chance when tested using the chi-square test. In terms of their personal skills, participants self-reported statistically significant changes (p < 0.05) in their ability to avoid depression, avoid loneliness, set priorities, achieve goals, solve problems efficiently, cope with constant cold, enjoy isolation, manage time efficiently, maintain physical fitness, be enthusiastic, demonstrate confidence and set goals. In terms of social skills participants self-reported statistically significant changes (p < 0.05) in their ability to control their emotions, motivate others, organise others, live in crowded circumstances, lead through consultation with others and maintain personal hygiene. In terms of technical skills participants self-reported statistically significant changes (p = 0.05 or smaller) in their ability to prepare dehydrated food, tie on and use ropes in glacier travel, use crampons and take charge of rescuing a member of their party from a crevasse. These items indicate that participants learned about survival and general skills associated with expeditions as a result of experiencing the expedition. This analysis of self-reported changes in items relating to expedition participants' personal, social and technical skills shows that participants have rated themselves more highly at the end of the expedition in a range of useful social/leadership skills and personality traits. The question of whether these same skills and traits could be transferable to higher education, employment and life in future is raised as a futher area for research. The improved technical skills reported will be useful if the participants undertake further expeditions to similar wilderness areas in future, perhaps as leaders. The potential of the findings of this study for training future leaders on expeditions is considered. Findings from this study may also be worthy of consideration by companies and organisations involved in personal development and training programmes.

A new record of Limnognathia maerski Kristensen &amp; Funch, 2000 (Micrognathozoa) from the subantarctic Crozet Islands, with redescription of the trophi

Abstract Limnognathia maerski, class Micrognathozoa, so far known only from Arctic Greenland, is reported from the subantarctic Crozet Islands. Fine morphology of the trophi is redescribed using scanning electron microscopy. Results show that the trophi are composed of the same functional units, i.e. incus, paired mallei and epipharynx, as found in Rotifera Monogononta. The zoogeography of the species is briefly discussed.

Spatial, seasonal and ontogenetic variation in diet of Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides )

This paper describes spatial, temporal and biotic patterns in the diet of Greenland halibut ( Reinhardtius hippoglossoides , Walbaum) sampled from three different areas of the Barents Sea, namely the Hopen Deep (nursery area), the Bear Island Channel and the continental slope (spawning ground), during April 1996 to January 1998. Percentage of empty stomachs was based on 3294 specimens, and the relative importance of prey groups was assessed using stomach contents from 486 specimens. Multivariate analyses (i.e. Correspondence Analysis and Canonical Correspondence Analysis) were applied to examine which variables could best account for dietary variation. Spatial (horizontal and vertical) and temporal components appeared to be most influential on the variation in diet composition, whereas biotic variables (i.e. predator size, sex and maturity stage) appeared to be of less importance. It is proposed that regional and seasonal differences in diet composition are caused by spatial and temporal variations in abundance and distribution of some of the major prey species, i.e. Atlantic herring ( Clupea harengus ) and capelin ( Mallotus villosus ). On the slope there were also clear ontogenetic changes in diet; in smaller Greenland halibut (<50 cm) crustaceans and the cephalopod Gonatus fabricii were the prevailing prey, whereas for larger specimens teleosts and fish offal were the dominating components of the diet. Smaller Greenland halibut appeared to have been foraging at greater depths (>700 m) than the larger ones.

Mapping pre‐ and post‐ fledging foraging locations of thick‐billed murres in the North Water polynya

In this study of thick‐ billed murres in high‐ arctic Greenland we used electronic data loggers and satellite transmitters (PTTs) to identify the foraging areas of chick‐rearing adults, and to map the routes and staging areas of adults accompanying post‐fledging chicks during their swimming migration within the North Water (NOW) polynya. During the pre‐fledging period the majority of 19 foraging trips performed by 8 birds went to a shelf area north of the colony where 83% of all dives took place. Individual birds headed in different directions during successive trips, and went up to 47 km from the colony. Upon fledging the four PTT‐tagged adult/chick pairs initiated swimming migration by heading south‐west from the colony. All pairs moved fast until they arrived at a shallow bank area ca 180 km from the colony, where at least two of the pairs remained for more than a week. Speed during the active migration averaged 2.5 km h‐1 with a peak of 6.6 km h‐1. In the pre‐fledging period the birds utilised a feeding area outside the normal foraging range of murres from other colonies. Similarly, post‐fledging adult/chick pairs may have benefitted from reduced food competition when they moved to a staging area situated at the only shallow area in the polynya without any adjacent murre colony. This initial study suggested that the high‐arctic murres did not hasten towards the wintering grounds, and that the NOW remained important even to post‐fledging murres.

Distribution and abundance of juvenile Northeast Arctic Greenland halibut (Reinhardtius hippoglossoides) in relation to survey coverage and the physical environment

Based on annual bottom-trawl surveys in the Barents Sea and Svalbard area in 1983–2000, variations in distribution and abundance of age 1 Greenland halibut (Reinhardtius hippoglossoides Walbaum) are described. The surveys showed high contrasts in abundance during the period, with extremely low abundance in 1990–1995 associated with a northerly displacement of the distribution within the survey area. A reduced abundance was not reflected in VPA-based estimates of total abundance of 1-group halibut. We conclude that the survey covered a varying proportion of the total distribution area. Survey abundance, the range of distribution within the survey area, and the proportion covered by the surveys were all negatively correlated with temperature in the Atlantic Water of the Spitsbergen Current. Possible mechanisms linking survey results to the physical environment are discussed.

Delineating Canadian and Greenland polar bear (Ursus maritimus) populations by cluster analysis of movements

Within their circumpolar range, polar bears (Ursus maritimus) are not subject to absolute barriers. However, physiographic features do cause discontinuities in their movements. These discontinuities in distribution can be used to delineate population units. Based on satellite telemetry of the movements of female polar bears carried out in 1989–1998, we used cluster analysis to identify 6 regions within the Canadian and western Greenland Arctic in which movements appear to be restricted enough to identify distinct populations. These regions generally correspond to management units that have been previously identified as Viscount Melville Sound, Lancaster Sound, Norwegian Bay, Kane Basin, Baffin Bay, and Davis Strait. A north–south substructure was identified for the Baffin Bay population, but it was weaker than the structure identified for the 6 primary units. The 6 units were consistent with genetic information, except for the Baffin Bay – Kane Basin separation, and with mark–recapture observations and the traditional knowledge of Inuit hunters. Only 2 of 65 bears that provided telemetry information for more than 1 year were classified in different populations in different years. However, annual rates of exchange, measured as the percentage of locations outside the population boundary, ranged from 0.4 to 8.9%. Analysis of mark–recapture movements indicated no difference in large-scale movements between the sexes or long-term movements with age. Although our validation criteria for demographic closure were satisfied, the observed rates of exchange between adjacent populations suggest that population dynamics in adjacent populations may not be completely independent.

Horizontal distribution of cladocerans in arctic Greenland lakes – impact of macrophytes and fish

Submerged macrophytes may play an important role as a refuge for zooplankton against predators. However, a recent study suggests that their importance depends on the trophic state of the lake. We studied the impact of fish and macrophytes on the horizontal distribution of pelagic cladocerans in 56 oligotrophic arctic Greenland lakes. In north-east and western Greenland, zooplankton was sampled in the near-shore (littoral) and central (pelagial) part of all lakes and fish were sampled with multiple mesh-sized gill nets. Macrophytes were visually estimated in the littoral. In north-east Greenland, 5 taxa of cladocerans were found, while 14 taxa were recorded in western Greenland. Daphnia pulex occurred only in fishless lakes in both northeast and western Greenland and avoided the near-shore areas in the shallow and deep lakes. Bosmina spp. and Holopedium gibberum were evenly distributed between the littoral and the pelagial in the deep and shallow fishless lakes. However, their near-shore density was lowest in the presence of fish. Macrophyte-related and benthic cladocerans concentrated either in the littoral or were evenly distributed between the littoral and the pelagial, irrespective of depth and fish presence or absence. Macrophytes had no impact on the horizontal distribution of pelagic cladocerans. Thus, it is concluded that horizontal heterogeneity of Bosmina spp. and Holopedium gibberum might be affected by the presence of fish.