Spitsbergen climatic conditions
Arctic climate is not amiable to plants and animals. Winters are long and cold, summers short and cool. What is more, spring and autumn are just short transition periods. The geographic location causes long periods of darkness during the polar night (some 3.5 months), thus limiting plant growth.
Life in Spitsbergen mainly huddles together at the border between sea and land. Only 6-7% of the island’s surface is occupied by forms of plant vegetation. Plants and animals had to adjust to very difficult and changeable living conditions. Because the pattern of sea currents (warm and cold) the east side of the Svalbard Archipelago differs from that on its west side; much richer flora and fauna develop on the west coast. The sea to the west of Spitsbergen is more productive and constitutes the biological base for huge colonies of sea birds. Species diversity is very poor, but the few species that occur do so in great numbers of individuals.
The perennial permafrost characteristic for this area reaches down several hundred metres into the ground, but the topmost 1 m – 2 m thaw in the summer. As a result of the poor outflow of water from this layer, referred to as the active one, flood waters form and the land has a marshy character.
Arctic nature is very sensitive and life regenerates very slowly here. Low temperatures mean that life processes and pollutant decomposition run slowly. Today, one can still see tracks and ruts left by off-road vehicles over 40 years ago!
During the short polar summer, algae, lichen, moss, fungi and flower plants complete their life cycle. Their flowers are minute, shoots short and leaves small. The coastal strip, sea-facing mountain slopes, and some valleys are covered with dwarf tundra. There are no bushes or trees here, dwarf polar willows take the form of shrubs not exceeding several centimetres in height.
Due to the limited number of insects, flower plants are anemophilous, as this pollination method is favoured by frequent strong winds which also transport seeds and spores over long distances.
Rock lichen and moss form colourful spots on stones, while in spots where soil has formed, colourful carpets of flowers and moss grow in summer. Compact concentrations of vegetation appear on slopes on which birds providing guano nest.
Birds
Most bird species feed out in the sea but breed on the land. They usually fly here for their breeding period, bring up their young, and fly south before winter comes (only the rock ptarmigan overwinters). One hundred and nine species of birds are recorded in Spitsbergen, fifteen of which regularly breed here. Others breed sporadically or fly in accidentally.
The first birds (fulmars) appear over high seas already in late January. March and April see the arrival of birds nesting on mountain slopes and cliffs, while those nesting in the tundra fly in later, in May and June.
The arrival of spring is heralded by the song of the snow bunting, similar to that of the skylark. This similarity is all the more astonishing because snow buntings start singing in April when winter conditions still prevail in the Arctic. Some species of birds, such as black guillemots and fulmars, winter on the edge of sea-ice, so they sometimes appear in Spitsbergen even during the polar winter.
All the most numerous bird species nest in colonies on steep rock walls (kittiwake, thick-billed murre, fulmar) and gentle mountain slopes covered in scree (little auk).
Birds that nest on the flat tundra (skua, purple sandpiper) are in more danger from predators (Arctic foxes), thus they tend to nest individually and use defensive tactics: enticing the aggressor away from the nest by pretending to be sick or scaring it away with aerial attacks. The Arctic tern can even injure a human with its sharp beak.
The largest avian predator is the glaucous gull, which hunts little auks and fish, steals eggs and chicks from nests, and is not averse to carrion or other organic waste.
The populations of nesting birds are quite numerous, with little auks being the most numerous: about two million.
Birds are protected and their nesting sites have been declared bird sanctuaries which must not be entered during the breeding period.
Marine mammals
The most numerous of the marine mammals in Hornsund is the fish-eating ringed seal whose breeding depends on the presence of a permanent winter-ice cover with snow. In those years where there is less ice in the fjord, these seals do not find breeding sites and move elsewhere. Other seal species that can also be observed here include: the bearded, harbour, grey, hooded and harp seals.
Walruses and beluga whales (white whales) can also be seen in the waters off Spitsbergen. Three species of dolphins, common minke whales, orcas and sperm whales appear sporadically.
There is also a maritime/land mammal – the polar bear, which is the largest predator on Earth. It can be encountered on the coastal strip or on high seas where it hunts its main prey, namely seals. It uses drifting sea ice to travel. The population of this animal in Svalbard is estimated at some 3,000 individuals, and the polar bear has been a protected species in this area since 1973.
Fishes
More than 30 fish species can be found in Hornsund, but most of them are small species that live at greater depths. The most important and most numerous one is the 20 cm long polar cod, which constitutes the main prey of seals and fish-eating birds of the Arctic. Laminaria thickets are the habitat of three species of small fish from the Cottidae family (popularly known as sculpins), while under stones in the tidal zone, eelpouts hold onto stones with their belly suction cups. In spring, the fjords are visited by 2 m long Greenland sharks, but these are rarely seen as they occur at great depths.
Salmon swim up the freshwaters of Spitsbergen to spawn.
Benthos (sea-bottom-dwelling organisms)
The bottom fauna of Hornsund consists of some 600 species and is dominated by crustaceans (102 species), polychaetes (69 species) and molluscs (52 species). Benthos biomass ranges from 10 g in bays near glaciers to 200 g of wet weight per 1 m2 in the outside part of the fjord. In shallow waters, Laminaria thickets can reach many kg per 1 m2.
The tidal zone of skerries is inhabited by rich communities of animals associated with Fucus and Balanus barnacles. The number of species of large algae holding fast to the bottom (known as macrophytes) exceeds 43 in Hornsund and includes the edible “dabberlocks” (Alaria esculenta). Of the Spitsbergen fjords on the west coast of the island, Hornsund has the greatest proportion of Arctic fauna, particularly in its outside part. The high seas are dominated by migratory thermophilous Atlantic species.
Plankton (small organisms suspended in water)
In Hornsund, phytoplankton bloom starts in late April and lasts until the end of May, with primary production reaching 120 g of carbon per m2 annually. Phytoplankton is dominated by diatoms, dinoflagellates and chryzophytes (altogether some 150 species). Zooplankton consists of some 60 species. It is dominated by copepods (genera: Calanus and Pseudocalanus).
Land mammals
There are only two representatives: the reindeer and the Arctic fox (a.k.a. white fox).
The reindeer subspecies inhabiting Spitsbergen differs from reindeer and caribou from Scandinavia, North America and Asia. Spitsbergen reindeer are more stockily built with shorter legs. They are whitish with grey and beige spots or completely white in winter. They live for up to 20 years. Both males and females have horns which they lose in early winter and regrow in spring. Reindeer not only cross glaciers and mountain passes but also swim well. They mainly feed on lichen.
The Arctic fox most frequently sports brown/grey summer and snow-white winter colouring, but foxes that stay black all year round have also been seen. It predominantly feeds on birds (particularly their chicks), eggs, fish and carrion. It digs breeding burrows in the ground, on slopes and between rocks. It lives for 12-14 years.
Foxes can be seen near the sea, in valleys and high on mountain ridges. They are territorial. Throughout winter until spring they frequently follow polar bears counting on the remains of their prey.