The Nature of Eyjafjörður and the surrounding waters

Eyjafjörður and Akureyri seen from Súlur © Ævar Arnfjörð Bjarmason

Eyjafjörður and Akureyri seen from Súlur © Ævar Arnfjörð Bjarmason

Vital ocean currents and freshwater runoff sustain a rich marine life

At the northcentral coast of Iceland the 60 km long and narrow fiord of Eyjafjörður stretches inland. There, nutritious and cold waters from the north are carried with coastal currents inside the deep fiord. The rivers responsible for providing this coastal area with freshwater runoff, loaded with various nutrients, are Svarfaðardalsá river and Hörgá river to the west, the Eyjafjarðará at the bottom of the fiord and Fnjóská river to the east.

Traces from the Irminger current creep into the west side of bay where it ultimately mixes with freshwater, creating coastal currents which travel clockwise around the Icelandic coast traversing all bays, fiords and coves as a conveyor belt, carrying plankton and larvae. The Irminger current, which is one of the branches of the Gulf Stream, is essential for this area as it brings warmer waters into the area and promotes mixing of cold and warmer water. Such mixing is important for bringing nutrients from the lower layers of the fiord up to the upper layers, where they are used by photosynthesising phytoplankton; the basis of the food chain. This mixing of cold and warmer waters also promotes movement of currents in and out of the area. The wild life depends on this circulation of currents, such as for distribution of fish larvae into nursing areas and for mixing of nutrients into the upper layers.

The unique Eyjafjörður

Eyjafjörður and the surrounding waters host rich marine life where hidden gems lurk in the deep. In these waters you can find the largest animals on earth and those that grow to be the oldest. The largest one is the majestic blue whale, a 30 m and more than 100 tonne giant, which visits the north coast of Iceland every summer to feed on zooplankton. The oldest living animals on earth is an Icelandic inhabitant which lives in Eyjafjörður and can get as old as 400 years, are the ocean quahogs (Arctica islandica). This interesting animal is a clam and actually important as an exploitable marine stock.

 

Another remarkable phenomena found in Eyjarfjörður are three hydrothermal vent sites with numerous chimneys found at an unusually shallow depth, or only 65 m. Evidently, nowhere else in the world have these geographical wonders been found in such shallow waters and can thus be reached by divers, but they are usually found below 500 m (Learn more about hydrothermal vents).

The Eyjafjörður Hydrothermal Vents

Hydrothermal chimneys at Ystavík in Eyjafjörður called Ystuvíkurstrýtur © Erlendur Bogason 

Hydrothermal chimneys at Ystavík in Eyjafjörður called Ystuvíkurstrýtur © Erlendur Bogason 

The chimneys found at the bottom of Eyjafjörður are slightly different from the deep water (> 1000 m) hydrothermal vents found around the world. They are actually formed when 70 – 80°C freshwater from land, not seawater, streams up through the bottom crust. The precipitating minerals in the freshwater streams are different from those normally found at the deeper water hydrothermal vents sites. Various creatures are found at the Eyjafjörður hydrotherma vents, from heat loving bacteria to a diversity of invertebrates and commercial fish species.

The diversity of life in Eyjafjörður and the surrounding waters

These two different water masses that meet off the northern coast of Iceland, i.e. the cold Arctic water and the warm temperate Irminger current from the south, influence the species composition in Eyjafjörur and the surrounding waters. Both temperate species and Arctic species can be found there. The most abundant fish species in Eyjafjörður are those that prefer to live at the boarders of the cold and warm zones. These are the most common species in Eyjafjörður, such as the cod, haddock, saithe, herring and lumpsucker which all are important exploited species in Iceland. The fiords at the north are important nurseries for juveniles of these important fish species.

 

What lurks at the bottom?

Greenland shark (Somniosus microcephalus)

Greenland shark (Somniosus microcephalus)

The bottom of Eyjafjörður provides various habitats at different depths and conditions. Whether these are vast mudflats or hot water spewing chimneys, life thrives in every place. Hidden underneath or crawling on top of the muddy planes are numerous animals and a diversity of species. These animals are called benthic animals and life at the bottom either partly or throughout their lives. Benthic animals mainly feed off kelp, sediments and other animals, some are important scavengers, feeding off rotting animals and plants which fall down from the upper layers, and some live as parasites. The benthic fauna in Eyjafjörður constitutes of e.g. starfishes, sea urchins, sea stars, clams, whelks and other snail species, sponges, different worms such as flatworms and polychaetes worms and various small crustaceans along with lurking, predatory flat fishes and even the ferocious but slow moving Greenland shark.

What swims about in the water column?

Seasonal bloom of phytoplankton during spring and again during fall brings the upper layers of the ocean around Iceland to life by attracting variety of pelagic animals (animals swimming above the bottom). From the small microscopic zooplankton to the enormous baleen whales. The phytoplankton sustains life in the upper layers of the ocean by producing organic material (sugars) aided by the sun’s energy and nutrients in the water. During winter, essential nutrients such as phosphor, nitrogen and iron accumulate in the upper layers of the ocean since there is very little of photosynthesising algae to use them up during the darkest months. Therefore, in spring, there is a plenitude of nutrients for the phytoplankton to use in the upper layers as the sun starts rising in the sky. As the phytoplankton blooming increases the zooplankton arrives with microscopic organisms such as copepods and krill (both crustaceans) to multiply like never before. Schools of zooplankton, which in addition to tiny crustaceans are also comprised of fish larvae, worms, jelly fish and other microscopic animals, graze on the phytoplankton. Larger animals, such as small schooling fish (e.g. herring and capelin), subsequently feed on the zooplankton and are themselves prey items for larger fish, whales, seals and birds.

The marine mammals of Eyjafjörður and the surrounding waters

Bottlenose whale (Hyperoodon ampullatus) jumps out of the water at the inner part of Eyjafjörður during the fall

Bottlenose whale (Hyperoodon ampullatus) jumps out of the water at the inner part of Eyjafjörður during the fall

Number of different whale species are seen off the north coast during summer, particularly in Eyjafjörður and the neighbouring Skjálfandi Bay. These whales visit the bays and fiords at the north to feed mainly on krill, sand eels, but also small cod fishes (e.g. Atlantic cod, haddock, saithe) and possibly pelagic schooling fish such as herring, capelin and mackerel. These whales are predominantly the blue whales, which is most commonly seen in these waters during spring and early summer (May-June), the humpback whale which can actually be seen there more or less throughout the year, minke whales, white-beaked dolphins, harbour porpoises, killer whales, and some less common, off-shore species, such as fin whales, sei whales, sperm whales and bottlenose whales.

The gray seal and the harbour seal are the most common seal species in Iceland and the only species breeding in Iceland. Seals are not as common off the central- and eastern north-coast such in the northwest and southwest but haul-outs and seal colonies are not very common in Eyjafjörður. During the winter, however, is when the wandering seals from the Arctic show up at the north coast of Iceland. These are mainly the bearded seals, harp seals, ringed seals, hooded seals and occasional walruses.