There is an intimate link between the ecosystems in the sea and on land. In particular, there is extensive transport of energy from sea to land through nesting sea birds bringing food from the water back ashore. In addition, some marine mammals dwell on land for shorter or longer periods for birthing and moulting. Pregnant female polar bears hibernate in the snow in late autumn.
Marine mammals in the Svalbard area include whales, seals and polar bears. Seals dominate in terms of numbers, while whales dominate in terms of biomass.
Marine mammals in the Svalbard area include whales, seals and polar bears. Seals dominate in terms of numbers, while whales dominate in terms of biomass. Polar bears are also considered to be a marine mammal, as they spend much of the year out on the sea ice and almost exclusively obtain all their nourishment through marine species.
Six of the marine mammal species in Svalbard are considered to be “indigenous” in a legal sense, i.e. they are managed through the Svalbard Environment Act. These are ringed seal, harbour seal, bearded seal, walrus, beluga whale and polar bear. This is a legal step in order to identify species which are not to be managed under more harvesting-focused fisheries legislation.
Five marine mammal species are on the Red List for Svalbard.
There are over 80 whale species in the world. Of these, four or five species can be commonly encountered in the Svalbard area, while around ten other species occur more or less rarely. There are three whale species that breed and remain in this area all year round: beluga whale, narwhal and bowhead whale. The beluga whale is commonly seen, particularly in the fjords of Svalbard, while the other two are less common. In addition, a number of other whale species visit the Svalbard area from the south in order to hunt for food during the summer, the most common of these being the minke whale, fin whale and humpback whale. The largest species of all, the blue whale, which is the largest animal that has ever lived on Earth, weighing in at 200 tonnes and being up to 30 metres long, has increasingly been observed around Svalbard at certain times of the year, even in the inner reaches of the fjords. Most of the whales are primary consumers, with the exception of some baleen whales, which are secondary consumers.
There are four commonly occurring seal species in Svalbard. The most common are ringed seal and bearded seal. There are also several thousand walrus which form part of a population that we share with Russia. There is also a small genetically isolated population of harbour seal, which primarily occurs on the west coast of Svalbard. At times, there are also large numbers of harp seal in the Svalbard area; these are seals which breed outside the Svalbard area (the “East Ice” and the “West Ice)
Polar bears in Svalbard belong to the Barents Sea population, one of 19 recognised sub-populations. This population was counted at approximately 685 animals in the Norwegian area in 2004 and at 975 animals in 2015. However, these figures are subject to considerable uncertainty.
Warming of the climate is reducing the availability of sea ice. This represents the main threat to many of the marine mammal species in the Arctic, particularly those which rely entirely on the sea ice in order to move around, to mate and feed their young, and to find food. The two most ice-dependent species are ringed seal and polar bear, and major consequences are anticipated for the populations of these two species both in Svalbard and globally if the reduction in ice cover continues.
Of the marine mammals, minke whale is the only species to be hunted commercially in Norwegian areas. In addition, two species are also hunted: bearded seal and ringed seal. However, the scope of the hunting is not sufficient to impact on the population, which is also a prerequisite under the Svalbard Environment Act. Hunting is also subject to time restrictions. The commercial hunting grounds for harp seal are located outside Svalbard.
As a top predator, polar bears are particularly susceptible to the bioaccumulation of pollutants. However, polar bears are able to metabolise pollutants, which is not always a benefit, as many of the metabolites can be more hazardous than the original compounds. Other species, such as beluga whale and toothed whales, have a very poor capacity to break down such substances and therefore have higher concentrations of many contaminants than polar bears, although beluga whales are lower in the food web. Orca have also been found to contain particularly high concentrations of certain pollutants.
Marine mammals can be very challenging to monitor, as they spend much of their time out at sea and under water.
Polar bears are monitored through tracking using satellite transmitters, through population counts, through studying reproduction rates, as well as through comparisons of density of dens and ice cover around key den areas in the Svalbard area.
Walruses in Svalbard are monitored via satellite transmitters and population counts at regular intervals. Selected haul-out sites of walrus (see the map of Svalbard) are monitored using cameras in order to look at the dynamics of the use of these sites, as well as the potential effects of visits by tourists.
Transect counts of whale species at sea are carried out regularly, with a particular focus on minke whale, a species that is hunted. Beluga whales are monitored through tracking via satellite transmitters, and a first count of these whales is planned in the near future. Otherwise, the three indigenous whale species are monitored using acoustic listening buoys deployed at various locations in the Svalbard area.
Harbour seals in Svalbard are monitored through tracking via satellite transmitters and through population counts at regular intervals (on only one occasion to date). The most ice-dependent species apart from polar bear, the ringed seal, is very difficult to monitor, but efforts are being made to develop methods for monitoring the species.
The species composition of marine mammals is covered by the Environmental Monitoring of Svalbard and Jan Mayen (MOSJ) system and the Barents Sea management plan. Indicators for marine mammals are also being developed in the Circumpolar Biodiversity Monitoring Program (CBMP) and the Norwegian-Russian environmental monitoring programme for the Barents Sea.
Marine birds, or seabirds, are bird species that obtain their nourishment from the sea. Some seabirds obtain all their food from the sea, while other seabirds obtain a proportion of their nourishment from the sea. Seabirds are a vital group of animals in Svalbard, as they provide a link between the marine and terrestrial ecosystems. Seabirds are responsible for a massive transfer of nutrients from the sea to the land, a process which gives most ecosystems in Svalbard a marine association.
Marine birds, or seabirds, are bird species that obtain their nourishment from the sea. Some seabirds obtain all their food from the sea, while other seabirds obtain a proportion of their nourishment from the sea. Seabirds are a vital group of animals in Svalbard, as they provide a link between the marine and terrestrial ecosystems. Seabirds are responsible for a massive transfer of nutrients from the sea to the land, a process which gives most ecosystems in Svalbard a marine association.
The number of breeding species is not particularly impressive, but the individual richness of certain species can be high. As of 2014, 212 bird species were recorded in Svalbard and surrounding areas. Of these, 28 species are considered to be ordinary breeding birds, while 20 are seabirds.
Svalbard has a number of important seabird areas, including 15 bird reserves (see the locations of these reserves on the map of Svalbard). Many of these areas were originally protected because of their importance for common eider and geese, but many are also important as overwintering areas for numerous species, including a high proportion of the population of long-tailed duck, as well as eiders, king eider, glaucous gull and black guillemot. Banks/shallow water areas are important rearing and moulting areas for common eider, king eider and long-tailed duck. The marginal ice zone is particularly important for grazing ivory gulls, thick-billed murre and little auk, and the area in front of glaciers is especially important for ivory gulls, kittiwakes and fulmars.
Many of Svalbard’s breeding seabird species are on the Norwegian Red List, either because they exist in small populations or because they exhibit a negative population trend. This applies to the following species: razorbill, glaucous gull, ivory gull, kittiwake, thick-billed murre, common guillemot and Sabine’s gull.
The main threat to the seabirds in Svalbard is the changing climate. For some species that are at the northern limit of their extent of occurrence, a change in climate could have a positive impact. However, changes in sea temperature also alter the prevalence and distribution of key prey, which can have a negative impact on seabird populations, due to the birds being unable to find food where and when they need it during the breeding season.
During the breeding and moulting seasons, seabirds are very vulnerable to marine pollution. Tiny droplets of oil in the birds’ plumage reduce the insulating properties of the feathers, causing the birds to freeze to death. Environmental pollutants also represent a major problem for certain species, such as the glaucous gull. Most birds in Svalbard are migratory and are therefore also vulnerable to external factors when they are not in Svalbard.
Seabird populations are monitored for various reasons. There are sometimes tens of millions of individual seabirds in the Barents Sea area, and the species that make up the majority of this biomass, such as thick-billed murre and kittiwake, are monitored as they are key ecological components in the Barents Sea, and changes in the population will have consequences for many other species. Populations of other species are monitored as they are sensitive to climate change and pollutants, such as ivory gull and glaucous gull.
The monitoring of seabirds forms part of the Environmental Monitoring of Svalbard and Jan Mayen (MOSJ), SEAPOP, the Circumpolar Biodiversity Monitoring Program (CBMP) and the Norwegian-Russian environmental monitoring programme for the Barents Sea.
Arctic species can spend their whole life in the area (e.g. Arctic cod, common snailfish, snakeblenny and eelpout), whilst arctic-boreal species can live in several areas, but the location of the spawning area will determine the designation.
Fish which can occur in the waters of Svalbard (as well as over a larger area) can be grouped into pelagic fish (e.g. capelin and herring) and demersal fish (e.g. cod, haddock, pollack, redfish, cusk, wolffish, halibut and Greenland halibut (which can also occur pelagically)).
Commercial species are fished for human consumption or as industrial fish (e.g. capelin, cod, haddock, Arctic cod, Greenland halibut, halibut, wolffish), while non-commercial species which are caught are discarded (e.g. American plaice, skates, sculpins, common snailfish, snakeblenny and eelpout).
Arctic cod is a key species in the ecosystem. Photo: Peter Leopold / Norwegian Polar Institute
Arctic species can spend their whole life in the area (e.g. Arctic cod, common snailfish, snakeblenny and eelpout), whilst arctic-boreal species can live in several areas, but the location of the spawning area will determine the designation. This applies, for example, to American plaice, snakeblenny, lumpsucker and Atlantic wolffish. Boreal species spawn off the coast of Central and Northern Norway, but spend all or part of their lives in the Barents Sea, including around Svalbard (e.g. cod, haddock, pollack, herring, Greenland halibut and redfish). More details regarding prevalence in the Svalbard area and the Barents Sea in August-September 2004 – 2009, life history, population estimates and catches.
Atlantic cod, Arctic cod, capelin, herring, American plaice and shorthorn sculpin from Lieftefjorden, Svalbard. Photo: Geir Wing Gabrielsen / Norwegian Polar Institute
The Greenland shark is the largest fish in Arctic waters, with a maximum length exceeding 4 m and a weight of over 600 kg. Little is known about the species’ movements and habitat preferences, but the tagging of individuals in Kongsfjorden indicates that they are widely distributed and probably make use of the entire water column when hunting for prey. Ringed seals, bearded seals, hooded seals, cod, Atlantic wolffish and haddock all constitute its prey. Greenland shark may have a significant predatory role in the Arctic food web. The size of the population around Svalbard is unknown, but it is probably substantial, as commercial fishing ended in the middle of the last century. Fishing for Greenland shark along the coast of Greenland during the 1940s recorded annual catches of up to 50,000 individuals, which were caught for their oil-rich liver.
The nutritional content of fish varies with age, size, season and time of day. A fish population can be affected in numerous ways, e.g. through fish eating each other, through them competing for common food resources, predation from organisms higher up the food web, environmental factors (which have a decisive impact on the survival rate of larvae) and the volume of inflowing Atlantic water.
If a key species is affected by changes in predation, by major reductions in biomass (e.g. fish) or by environmental changes, the entire ecosystem could be affected. For example, both Arctic cod and capelin are of decisive importance for the diversity of their respective ecosystems (ice-filled/ice-free areas). Both are vital sources of food for many species at higher trophic levels. Cod and herring are considered to be key species in the southern Barents Sea, while prawns and Arctic cod are key species in the northern Barents Sea. Capelin spawn along the coast of Finnmark, but can migrate all the way up to the ice margin in the northern Barents Sea. It can therefore be a key species in both the southern and northern Barents Sea, but because the population exhibits substantial fluctuations with very low biomass over periods of 8 – 10 years, it is a relatively unstable food source. When capelin numbers are down, there is a food shortage for some species of seabirds and other high-level animals in the food web of the Barents Sea.
Some of the fish species around Svalbard have Red List status.
Distribution of cod and capelin in the northern Barents Sea, autumn 2010, 2011 and 2012. The white areas indicate ice cover and the thin black lines indicate depth. Figure: Havforskningsrapporten 2013.
Fisheries are the only form of exploitation that can currently be considered to be impacting on the marine ecosystem, either directly through (over)exploitation of the fish populations that are being fished, as well as any bycatch species, or indirectly through changes in the nutritional basis for seabirds and marine mammals. In addition, commercial species exhibit natural fluctuations which can be either amplified or dampened with large-scale fisheries.
Of the commercial species, direct fishing is carried out for cod, haddock, Greenland halibut, northern wolffish, Atlantic wolffish and spotted wolffish, although cusk are only taken as a bycatch in the waters around Svalbard. However, fishing largely takes place more than 12 nm from the coast.
Cod is one of several species that has been moving steadily northwards (see the figure in status), a fact that is also reflected in the fishing. Cod, haddock and Greenland halibut are closely associated with the ocean floor, and it is therefore unlikely that they will spread further north than the continental slope north of the Barents Sea. Capelin are a pelagic species and thereby have greater potential to move into the Arctic Ocean, but for the time being it appears as though factors other than the absence of ice are playing a role, including food availability (in particular copepods and the distance to the spawning grounds.
Spawning populations of Greenland halibut, north-east Arctic cod, cod, beaked redfish and common redfish, biomass and the prevalence of blue whiting and young herring, as well as mature populations of capelin, are covered by the monitoring carried out under the auspices of the Barents Sea management plan, which also covers the marine areas around Svalbard.
With the exception of blue whiting, the same species are included in the Environmental Monitoring of Svalbard and Jan Mayen (MOSJ). Indicators for various species of fish are also being developed in the Circumpolar Biodiversity Monitoring Programme (CBMP) and the Norwegian-Russian environmental monitoring programme for the Barents Sea.
Northern prawn (Pandalus borealis) Photo: Fredrik Broms
Of the prawn species found in Norwegian coastal waters, only the northern prawn (Pandalus borealis) is of any major economic significance. It enjoys a circumpolar, Arctic boreal distribution. A number of factors govern its prevalence, including depth (observed from 20 – 900 m, but most commonly 100 – 700 m), salinity, temperature (main regulator for prevalence and life-cycle) and characteristics of the bottom (soft clay bottoms are best). The key prawn grounds have a temperature of between 1 – 3 °c, but prawns are found in water masses with a temperature of between – 1.7°C and 13°C. In years with a lot of ice, low water temperatures can contribute to impoverished cohorts in prawns, e.g. in Isfjorden. Northern prawn have vertical migrations, but become more closely associated with the bottom as they grow older. Prawns are important sources of food for cod and other fish that forage near the bottom.
Prawn fishing is conducted in several fjords and coastal waters in Svalbard. Rising fuel prices and falling prawn prices have affected the level of activity in shrimp fisheries, which has been one third below scientists’ recommendations in recent years. However, there are now signs of rising prawn prices, which could impact on the future level of activity.
PHYTOPLANKTON Spring bloom of phytoplankton north of Svalbard, May 2010. Photo: Cecilie H. von Quillfeldt
Phytoplankton are microscopic algae that move passively with the sea currents; they have little or no motion of their own. There are many different groups, of which diatoms are one of the most important in Svalbard. Biomass and species composition vary considerably through the year and between years. Most species have a circumpolar distribution because they follow the ocean currents around the Arctic. Important regulating factors are temperature, salinity, convection in the water masses, light, nutrients, water depth, grazing and depth of sedimentation. Over 1,800 species have been reported in the Arctic, although there are also many, particularly small flagellates, that have not yet been described
ZOOPLANKTON Calanus glacialis is a typical zooplankton species in arctic water masses. The green intestine is caused by grazing on phytoplankton. Photo: Allison Bailey/Norwegian Polar Institute
Zooplankton can be divided into two main groups: holoplankton, which live planktonically throughout their entire life (e.g. copepods), and meroplankton, which only live planktonically for a certain period of time (e.g. barnacle and crab species). Key species of crustaceans are large copepods (Copepoda), e.g. Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus, small copepods (Copepoda), krill (Euphausiacea) and pelagic amphipods (Amphipoda). Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus are all important species in the Svalbard region, but their main prevalence is governed by water type, depth and distance to the coast and continental shelf. Most species rise up from the depths in order to graze on spring algal blooms, although often at different times as regards their most intense grazing phase, so reducing competition between the species.
Sea angels (Clione limacina) is at times an important species of zooplankton in the Barents Sea. Photo: Bjørn Gulliksen.
Any changes in primary production could have consequences for higher links in the food web. The importance of this dynamic adaptation to primary production, and the way in which any climate changes will affect it, is therefore a key issue within research into the effects of climate changes.
The relationship between zooplankton and predators depends on the choice of prey, the time of grazing, the size of overwintering populations, and growth and production conditions for juvenile plankton populations. Another large and important group in Svalbard is gelatinous plankton (planktonic animals with a very high water content and a gelatinous physical consistency). Main groups of gelatinous plankton include jellyfish (phylum: Coelenterata), comb jellies (phylum: Ctenophora) and arrow worms (phylum: Chaetognatha). Most feed in the layers with copepods. They are usually tactile predators which capture plankton in nets with nematocysts (stinging cells) or mucus, which paralyses and sedates the prey. Arrow worms have eyes and are therefore a visual predator.
Calanus finmarchicus is an important species in the Svalbard region.
Photo: Norwegian Polar Institute
Many of the zooplankton species are important sources of food for other animals in the marine ecosystem. Calanus glacialis is an important source of food for Arctic cod, capelin and little auk, while the amphipod Themisto libellula is the principal source of food for many diving seabirds, such as thick-billed murre and black guillemot. This gives T. libellula a key role in the Arctic marine ecosystem.
Species’ preferences for different environmental conditions can be utilised in monitoring and studies of the effects of climate change. For example, the discovery of planktonic species typical of Atlantic water makes it possible to follow the transportation of Atlantic water up along the west coast of Svalbard and north to the Jermak Plateau, where it appears beneath cooler Arctic waters. Deeper water which is forced up onto the plateau carries with it deep-sea species, such as the copepod Scaphocalanus magnus.
Impacts/threats/vulnerabilities
Species composition, prevalence, quantity and physiological processes are closely associated with the ocean environment. Changes in physical and chemical drivers (temperature, salinity, pH, current conditions) which are affected by climatic conditions could have major consequences for the marine ecosystem. Some species, such as the sea butterfly Limacina helicina, are also more susceptible in relation to ocean acidification
The species composition and biomass of zooplankton are covered by the Environmental Monitoring of Svalbard and Jan Mayen system (MOSJ) and the management plan for the Barents Sea. The latter also covers the species composition of phytoplankton, biomass and production expressed as chlorophyll a, and the timing of spring blooming. Annual expeditions have been carried out in Kongsfjorden in Svalbard since 1996 in order to take samples along a transect extending from the innermost part of the fjord, over the shelf and Eggakanten and out into Framstredet. This marine time series is now the longest-running pelagic series in the Arctic, and is being carried out as a partnership between the Norwegian Polar Institute and the Institute of Oceanology in Poland. Indicators for phytoplankton are also being developed in the Circumpolar Biodiversity Monitoring Program (CBMP) and the Norwegian-Russian environmental monitoring programme for the Barents Sea.
Benthic flora are dominated by macroalgae, although some lichen species and microalgae live in the intertidal zone. At greater depths, benthic microalgae (in particular diatoms) can survive on the ocean floor if the light conditions are satisfactory.
Several species of sea anemones at Sjuøyane, Svalbard. Photo: Bjørn Gulliksen
Benthic fauna live on or just above the ocean floor, and can be divided into hyperbenthos (live above the seabed), epifauna (live on the surface of the sediment or rocks) and infauna (live buried in the sediment). Hard bottom fauna live on rocks or bedrock, often as sessile individuals, while soft bottom fauna live on loose material that can be collected using a grab. Benthic fauna can be grouped according to their method of feeding (across taxonomic boundaries), i.e. those that filter the water masses, those that consume sediment and dead organic material (detritus), carnivores, herbivores and omnivores. Environmental conditions, such as temperature, salinity, ice conditions/ice scouring, current conditions, light and nutrient salts (for algae) and habitat (type of substrate, exposure, etc.) are of importance as regards prevalence. The most common animal groups are sponges (Porifera), stingers (Cnidaria), bristleworms (Polychaeta), crustaceans (Crustacea), molluscs (Mollusca), moss animals (Bryozoa), echinoderms (Echinodermata) and sea squirts (Ascidiacea), as well as fish (e.g. sculpins and eelpouts). Typical species on hard bottoms are barnacles (Balanus balanus), green sea urchin (Strongylocentrotus droebachiensis), wrinkled rock-borer (Hiatella arctica), Iceland scallop (Chlamys islandica), bryozoa (Tricellaria ternata, Eucratea loricata), colony-forming sea squirts (Synoicum sp.) and sponges (Haliclona aqueductus). On soft bottoms, you will often find polychaetes (Spiochaetopterus typicus, Maldane sarsi and Lumbrinereis spp.), brittle stars (Ophiura Robusta, Ophiocten sericeum), snails (Buccinum undatum), burrowing molluscs (Mya truncata, Serripes groenlandicus) and soft-bottom corals (Gersemia rubiformis). The biodiversity can be high, except in pools that are strongly affected by sedimentation. Key commercial species of demersal fish are cod, Greenland halibut and American plaice.
A comparison of Sassenfjorden in Svalbard and a corresponding area in the North Sea showed little difference in overall diversity. On several of the small islands n
Snow crab is a new species for the Barents Sea (first found in 1996), but it is uncertain where it comes from. Estimates show that the snow crab has considerable potential for harvesting. Photo: Cecilie H. von Quillfeldt/Norwegian Polar Institute
orth of Spitsbergen, there is solid bedrock and relatively little run-off from the land. Such locations can be home to large densities of sea anemones, for instance. Areas such as Sørkappbanken, Sentinelleflaket, Sjubreflaket and Breibogen are greatly affected by the Atlantic Current and are often characterised by bedrock and rocks. The species found here are generally sensitive to “particle rain” supplied with meltwater, and they are often the same as on sloping bottoms in the fjords (e.g. at Kapp Linné).
The southern tip of Spitsbergen is also a biogeographic boundary, as the west coast is dominated by sub-Arctic species such as barnacles (Balanus balanoides), the rough periwinkle (Littorina saxatilis) and the amphipod Gammarus oceanicus in the littoral zone, whereas another amphipod, Gammarus setosus, dominates on the east coast.
On the mainland, coral reefs are often referred to as a rare habitat type. No coral reefs have yet been found in Svalbard, although it is not unreasonable to expect them to be present (e.g. “Lophelia reefs”), particularly on the southwestern side.
Example of epifauna (benthic fauna on the sediment surface) in Wijdefjorden. Photo: Bjørn Gulliksen
The Iceland scallop (Chlamys islandica) is normally found in areas exposed to strong currents at depths of 20–100 m. In Svalbard, these scallops live to a maximum age of 25–30 years.
The Iceland cockle (Ciliatocardium ciliatum) has been studied in connection with expeditions to the Svalbard zone. It is not certain to what extent this and the Iceland scallop are a food source for bearded seals and walruses, which have probably replaced the blunt gaper (Mya truncata) and the Greenland cockle (Serripes groenlandicus) as their main food. Iceland cockles can live for up to 30 years, while other species can live for more than 30 years. The wrinkled rock-borer (Hiatella arctica) can live to over 100, but it is difficult to determine the age of old individuals by counting dense annual growth rings. Analysis of growth in shells can provide important indications of changes in climate over time.
The Iceland scallop resources north of Svalbard were the largest in the Norwegian economic zone, and were exploited commercially from the mid-1980s. Fishing was suspended in 1992. Studies of shell-fields, including those around Moffen, every ten years, show good recruitment and increased shell density compared with the time when fishing was suspended. The Iceland cockle is considered to be a delicacy and is harvested elsewhere in Europe. This species and other large, burrowing molluscs, such as the Greenland cockle, are also potentially commercial resources in our territorial waters.
Benthic communities will be affected in areas with bottom trawling. Only shrimp trawling and trawling for research and monitoring purposes are permitted within the protected areas of Svalbard.
Stationary bottom-dwelling animals in particular are suitable for impact studies and the monitoring of problems associated with climate change and environmental toxins, as the species composition reflects the local regime and will therefore be an important indicator of environmental quality.
As benthic communities can provide valuable information concerning pollution in an area, regular studies of these communities can be useful in areas which have been colonised in order to draw comparisons with unaffected areas with similar fauna.
To a limited extent, benthic communities are covered by the regular monitoring programme, but species composition and numbers of benthic fauna, incidences of red king crab and prevalence of coral reefs, rugosa and sponges are indicators in the Barents Sea management plan. Indicators are also being developed in the Circumpolar Biodiversity Monitoring Program (CBMP) and the Norwegian-Russian environmental monitoring programme for the Barents Sea.
Algae on the underside of the ice. Photo: Bjørn Gulliksen
Ice algae are single-celled, microscopic organisms which are associated with ice and can act as colonies in the form of links or mats. They can occur anywhere on the ice, e.g. on the surface, in melt ponds, within the ice and in cavities and cracks, as well as on the underside of the ice, where they grow on ice crystals. The species composition and biomass are dependent in part on the age and structure of the ice, as well as the fact that there is a difference between fast ice and drift ice. The depth of the sea and distance to the land are important factors as regards which species are recruited to ice communities.
Gammarus wilkitzkii is a characteristic species of multiannual ice. Photo: Fredrik Broms
Given the right conditions, the growing season for ice algae can start up to two months earlier than for phytoplankton in the water masses. This is beneficial for Arctic zooplankton, such as the copepod Calanus glacialis. It rises from the depths in the early spring in order to graze on the ice algae, which contain a lot of energy in the form of sugar and fats. This is used for the development of eggs before spawning, and when the eggs hatch, the small nauplii utilise the subsequent phytoplankton blooms. A reduction or absence of ice in fjords, coastal areas and the open sea will therefore have consequences for total production in an area. However, there can be substantial annual variations in terms of both biomass and species composition. Ice algae that are not grazed become detached from the ice when the ice starts to melt and sink down through the water masses. If they are not eaten as they sink by zooplankton, they become a contribution to the benthic nutrient network. Some benthic communities are specially adapted to such periodic supplies of food. They may only be supplied with fresh algae from the overlying water masses on a couple of occasions a year.
Nitzschia frigida, Nitzschia promare and Thalassiosira bioculata are typical algae under one-year old ice. Photo: Else Nøst Hegseth
Ice fauna are animals which are associated with ice throughout all or part of their lifecycle. These include meiofauna, such as ciliates, nematodes and rotatories, and macrofauna which can be amphipods, copepods, fish (Arctic cod), seabirds and marine mammals. The latter are often known as ‘charismatic macrofauna’, with polar bears being an example.
The amphipods Apherusa glacialis, Onisimus spp. and Gammarus wilktzkii play an important role in ice communities, as they generally make up the majority of the total biomass of the invertebrate ice fauna in the Barents Sea. Apherusa glacialis graze directly on the ice algae, while Onisimus spp. also eat detritus which consists of organic materials from animals and plants in the ice. Gammarus wilkitzkii can be approx. 5 cm long and is an important predator, and is itself food for diving seabirds and seals. It is considered to be a characteristic species of multiannual ice because it has a lifecycle that spans 5–6 years.
Climate changes, which are leading to changes in the age, structure and distribution of the sea ice and fjord ice, could have substantial consequences for the composition and quantities of ice biota, which in turn will impact on the ecosystem. More about the effects of climate changes.
Some toxic compounds become incorporated into the ice when the ice is formed, from both the water and the sediments which become trapped in the ice as it freezes. In addition, toxic compounds are deposited and accumulated on the ice after they have been transported there by air currents over long distances. These are often called ‘long-range transported contaminants’ and may for example originate from industrial production in Europe or Asia. The ice is thus a transport mechanism that collects together many contributions. Ice organisms will also be particularly vulnerable to toxic compounds with a long residence time in the upper water layers (e.g. some PCB and PAH compounds).
There is no regular monitoring of ice biota, but an ice biota network under the auspices of the Circumpolar Biodiversity Monitoring Program (CBMP) collates available data concerning circumpolar species, quantities and occurrences as a basis for an assessment of status and trends in the Arctic.
Heterotrophic microorganisms differ from autotrophic organisms in that they do not have the ability to form organic compounds through photosynthesis. They utilise nutrients from water, organic matter or other organisms. There are two main groups of heterotrophic organisms. Bacteria are single-celled microorganisms where organic molecules are taken up through the cell membrane. Protozoa are colourless flagellates and ciliates, which can take up nutrients in particle form (e.g. dead particles, algae, bacteria and small protozoa)
Heterotrophic microorganisms are important in the remineralisation of nutrient salts, and they are grazed by larger microorganisms, as well as filtering animals, such as tunicates. The ecological and relative significance of bacteria versus protozoa varies according to the situation. These microorganisms belong to the microbial nutrient network, also known as the microbial loop. Much of the turnover circulates in this loop, while some is transported upwards in the food chain to the next trophic level, which could for example be represented by small crustaceans.
Viruses are in addition to bacteria and protozoa. In practice, they are counted under microbiology, but they are not living cells. They are responsible for breaking down bacteria and can attack anything from algae to larger marine animals (such as fish and seals). Viruses attach themselves to the cells and inject genetic material which causes changes in cells and organisms, and can also trigger serious diseases.
Despite its location in the far North, the archipelago of Svalbard has a rich and diverse birdlife. Numerically, it is the seabirds that dominate, but the terrestrial ecosystem is also home to many species.
A large number of different bird species have been observed in Svalbard (212 as at 01.01.2015), but only 28 of them are considered to be habitual nesting birds. 13 species are considered to be sparse, irregular or probable nesters and a further 12 have been recorded as nesting on at least one occasion. The remaining species are sporadic guests. As climate change progresses, observations of new species are expected in its wake, either as vagrants or as nesting birds.
Among the terrestrial bird species, the Svalbard rock ptarmigan and the snow bunting are probably the best known. The Svalbard rock ptarmigan is an indigenous sub-species of the ptarmigan and the only terrestrial bird that resides in Svalbard year-round. The snow bunting is a migratory bird, but, against that, is Svalbard’s only passerine.
In summer, the terrestrial ecosystem gains a number of migratory species that nest in the tundra landscape. Common nesting species are the red-throated diver, the brent goose, the barnacle goose, the pink-footed goose, the purple sandpiper, the European golden plover, the dunlin, the grey phalarope, the ringed plover, the sanderling, the ruddy turnstone, the red-necked phalarope. Of these, the purple sandpiper is the commonest and most numerous species, the red-throated diver is spread over most of Svalbard, typically at smaller lakes and tarns, while the populations of barnacle goose and pink-footed goose have grown strongly in the last 30-40 years.
Many of Svalbard’s birds are on the Norwegian Red List either because their populations are declining or they live as small, vulnerable populations at the extremes of their distribution ranges. This is the case for the waders (European golden plover, dunlin, red knot, red phalarope, sanderling, ringed plover and turnstone), long-tailed skua and brent goose.
The seabirds constitute an important link between the marine and terrestrial ecosystems, by fertilizing the areas within and around the bird cliffs. This creates a resource for nutrient-rich vegetation, which the terrestrial birds exploit.
The terrestrial bird species are affected by various environmental factors, of which climate change is the most important. The Svalbard rock ptarmigan which lives year round in Svalbard is affected negatively by mild rainy winters with iced-covered grazing which prevents access to grazing plants and limits food availability. An earlier start to spring can cause changes in nesting biology and a mismatch between the time of hatching and the nutritional content and presence of important grazing plants for the chicks, which are specialists. Similarly, increasing goose populations may cause more competition with the indigenous herbivores, ptarmigan and reindeer, for important grazing plants.
The Svalbard rock ptarmigan and pink-footed goose are harvested through annual small-game hunting by residents, visitors (only ptarmigan) and a few professional hunters. The Svalbard rock ptarmigan is the most popular and is harvested in the largest numbers, whereas far fewer pink-footed geese are shot. The population of pink-footed geese has increased rapidly as a result of a combination of land-use changes in the overwintering areas and climate change. A reduction of the population is desirable due to the strong influence that the pink-footed goose can have on processes and functions in the ecosystem, through, for example, pasture damage and competition for important grazing plants with the indigenous species.
The terrestrial bird species are vulnerable to human traffic to varying degrees. The most vulnerable period is the nesting time before hatching, and species which nest in concentrations or colonies are most vulnerable. This is the case, for example, for the pink-footed goose and the barnacle goose. Here, human foot traffic and low-flying helicopters may contribute to lower reproduction. The pink-footed goose has proved to be most sensitive to disturbances. The goose species are also vulnerable during moulting, in July-August.
The Svalbard rock ptarmigan has been included in MOSJ (Environmental Monitoring of Svalbard and Jan Mayen) since the annual monitoring began in 2000. It is proposed to include the pink-footed goose and barnacle goose in the scheme. The Svalbard rock ptarmigan and pink-footed goose are included in the COAT (Climate-Ecological Observatory for Arctic Tundra) scheme. It is considered important to register all three goose species and the ptarmigan in the Circumpolar Biodiversity Monitoring Program (CBMP).
Within Svalbard’s terrestrial ecosystem, only three species of mammal overwinter. The fauna consists of two herbivores: the indigenous Svalbard reindeer and a local, introduced population of the sibling and the predator and scavenger, the Arctic fox.
The mammals in the terrestrial ecosystem are vulnerable to and affected by climate change. Earlier snow melt in spring, warmer summers, longer growing season, milder winters with more precipitation and more frequent rainy periods will affect the food supply, living environment and the species’ demographic rates (reproduction and mortality). The effect of icing episodes leading to increased mortality and lower reproduction in Svalbard reindeer and southern voles is well-documented. The Arctic fox is affected indirectly by tundra icing with a negative response in growth potential, delayed by a year, resulting from ice-covered reindeer pasture. The greatly increasing stocks of geese nesting in Svalbard may be a positive factor for the Arctic fox due to an increase in access to prey in the form of adult birds, chicks and eggs. The Arctic fox also depends on access to sea ice in the fjords in late winter during the birthing period of ringed seals in order to obtain food. A lack of fjord ice in the spring months may cause this food source to disappear. If the sea ice in the Arctic Ocean disappears, the Arctic fox population in Svalbard will be isolated, since they use the sea ice as a platform for moving between the Arctic land masses.
Both the Arctic fox and Svalbard reindeer are harvested locally, but the present catch is not considered to affect the stocks notably. A restricted hunt of the reindeer for residents and a few professional hunters has been allowed in Svalbard since 1983. Between 117 and 235 reindeer are culled annually, in addition to a commercial quota. Residents catch Arctic fox in 25 hunting areas on Nordenskiöld Land and at Kongsfjorden in addition to a few professional hunters. Between 35 and 160 Arctic fox are trapped annually. Population monitoring data shows no clear indications of any consistent decline in population size despite the Arctic fox having been hunted over a long period. Explanations for this are that trapping occurs in restricted areas and that the population’s growth potential and/or immigration inhibits a reduction in its size.
Human traffic may affect both species, perhaps particularly in late winter after a hard winter, if there is a lot of snowmobile traffic in key grazing areas (Svalbard reindeer), during calving periods for Svalbard reindeer and near den locations (Arctic fox). There is data from provocation studies of foot and snowmobile traffic for Svalbard reindeer. These say something about the impact of traffic on individuals but its significance for the population’s survival and reproduction is unknown. In areas of large and regular snowmobile traffic, much points to the ability of Svalbard reindeer to become habituated to such disturbances.
Among the terrestrial species, it is only the Arctic fox that is subject to high levels of environmental toxins since it also feeds from the marine food chain. Otherwise, the terrestrial mammals are not so exposed to environmental toxins as marine species. The levels of toxins in Arctic foxes may be affected by climate change, since access to different prey species is strongly influenced by climate and the different prey have different levels of environmental toxins. There are reasons to believe that these high toxin levels may have negative effects on the foxes’ health.
The incidence of disease and parasites such as Echinococcus multilocularis and rabies in Arctic foxes is being investigated and is significant for animal health and the transmission of disease to other wildlife (reindeer) and human health (zoonosis).
The Svalbard reindeer and Arctic fox are included in MOSJ (Environmental Monitoring of Svalbard and Jan Mayen). At present, there is no monitoring of southern vole or the incidence of the Echinococcus multilocularis tapeworm. Annual reports are made of reindeer population numbers for central areas of Nordenskiöld Land (1979─ ) and on Brøggerhalvøya (1978─ ) and the proportion of dens with pups in Adventdalen/Sassendalen (1997─) and on Brøggerhalvøya (1993─). The numbers of culled reindeer and trapped Arctic foxes are also reported. Reindeer and Arctic fox are also key species for monitoring in the Circumpolar Biodiversity Monitoring Program (CBMP) and in the Climate-Ecological Observatory for Arctic Tundra (COAT).
Svalbard’s extreme isolation, in combination with its Arctic climate, has produced freshwater sites with very few species of plankton and benthic animals. Char is the only freshwater fish. Stoneflies, dragonflies, black flies and predaceous diving beetles are among the species found in most of the lakes of Northern Norway, but which have not yet been observed in Svalbard.
The dominant bodies of water are shallow (under 2 m deep) ponds and small lakes created by permafrost. These often have a high production of insects and crustaceans, may be significant biotopes for birds, and are highly vulnerable to permafrost thawing. These permafrost-dammed pools do not normally support fish since they freeze through to the bottom in winter, whereas Arctic char live in effectively all the lakes in Svalbard below the marine limit that do not freeze through (are deeper than 2 m).
Disappearing Arctic lakes. Science, 308: 1429–1429. 2005. DOI: 10.1126/science.1108142
