Iceland Sea

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Iceland Sea
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Borders of Iceland Sea according to IHO draft standard (2002)
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Iceland Sea
Coordinates 66°55′23″N12°37′44″W / 66.923107°N 12.628921°W / 66.923107; -12.628921
Surface area406,000 km2 (157,000 sq mi)
Average depth1,026 m (3,366 ft)
Water volume417,000 km3 (100,000 cu mi)
Islands None

The Iceland Sea, a relatively small body of water, is bounded by Iceland. It is characterized by its proximity to the Mid-Atlantic Ridge, which transforms into the Kolbeinsey Ridge, and the Greenland-Scotland Ridge, and it lies just south of the Arctic Circle. [1] This region is typically delineated by Greenland to the west, the Denmark Strait, and the continental shelf break south of Iceland to the south. [2] Next in the boundary line are Jan Mayen, being a small Norwegian volcanic island, and the Jan Mayen fracture zone to the north, with the Jan Mayen Ridge to the east of the sea. [2] [3] [4] This ridge serves as the northern boundary of the Iceland Sea, acting as the dividing line from the Greenland Sea. [1] To the immediate south of Jan Mayen, the Iceland-Jan Mayen Ridge stretches towards the Iceland-Faroe Ridge, creating a boundary between the Iceland Sea and the Norwegian Sea to the east. [1]

Contents

There were changes regarding the limits of the Iceland Sea as according to the International Hydrographic Organization, in its 1953 edition of the Limits of Oceans and Seas standard, the Greenland Sea comprises the entire area of the Iceland Sea. [5] However, in the proposed 2002 edition, the Iceland sea is now a defined zone of its own. [6]

Oceanographic features

The depths of the Iceland Sea generally fall within the range of 500 to 2000 meters, however, are shallower on the continental shelf of East Greenland and the outer shelf north of Iceland. [2] In contrast to the neighboring Nordic Seas, such as the Norwegian and Greenland Seas, the Iceland Sea is relatively shallow. [2]  Crossing through its central expanse in a southwest–northeast direction, the Kolbeinsey Ridge features areas within the sea that are as shallow as 500 meters, differing significantly from the surrounding waters which often exceed depths of over 1000 meters. [2]

The Iceland Sea is surrounded by two main water masses, each originating from distinct sources and possess unique characteristics. [1] First coming from the far south, warm saline Atlantic waters flow into the Iceland Sea from both the southwest as a branch of the Irminger Current, and from the east originating from the Norwegian Sea which then also passes through the Jan Mayen Ridge. [4] [7] The temperature of these Atlantic currents range from 6 to 11˚C depending on the season. [1]

The other main water mass are Polar waters which come from the Arctic Ocean. This cold, low-salinity water flows out of the Arctic Ocean through the Greenland Sea, and into the Iceland Sea by the East Greenland Current. [1] [4] Within the Iceland Sea, these

North Atlantic Water Circulation North Atlantic Circulation.gif
North Atlantic Water Circulation

two water masses meet, leading to varying proportions of warm and cold water. [4] Where warm and cold-water masses converge off the northwest and the off north coasts of Iceland, a frontal area forms. [1] [4] Additionally, another front forms from the middle of the Denmark Strait northeastward, towards the west of Jan Mayen. [4]

Marine life

The Icelandic Sea has a diverse ecosystem with a multitude of species within. Two groups of phytoplankton inhabit these waters being diatoms and dinoflagellates. [1] [4] Diatoms of the genera Thalassiosira and Chaetoceros are the abundant phytoplankton and are in large quantity during the springtime. [1] Whereas common dinoflagellates present are of the genera Ceratium and Protoperidinium that bloom after the spring, while the presence of diatoms is still high. Throughout the autumn season it is typical for a second bloom of diatoms to occur while dinoflagellates may still be abundant. [1]

Within these waters, zooplankton, specifically copepods such as Calanus finmarchicus are present and make up anywhere between 60% and 80% of the existing zooplankton population. [1] [2] Other copepod species commonly found are Pseudocalanus, Acartia longiremis , and Oithona , with other species being confined to Atlantic or Polar waters. [1]

Fish species that are found within the Icelandic Sea are cod ( Gadus morhu a), haddock ( Melanogrammus aeglefinus ), saithe ( Pollachius virens ), redfish ( Sebastes marinus ), herring ( Clupea harengus ), blue whiting ( Micromesistius poutassou ), capelin ( Mallotus villosus ), monk fish ( Lophius piscatorius ), and Greenland halibut ( Reinhardtius hippoglossoides ). [1] [2] [4]

The Iceland Sea inhabits five different species of invertebrates being the northern shrimp ( Pandalus borealis ), Norway lobster ( Nephrops norvegicus ), the Iceland scallop ( Chlamys islandica ), the ocean quahog ( Arctica islandica ), and the common welk ( Buccinum undatum ). [1]

Regarding marine mammals, there are eighteen species of cetaceans present such as whales, dolphins and porpoises are present, as well a seven species of pinnipeds such as seals and walruses inhabit the Iceland Sea. [1] Some of which being the minke whale ( Balaenoptera acutorostrata ), humpback whale ( Megaptera novaeangliae ), the blue whale ( Balaenoptera musculus ), the Atlantic white-sided dolphin ( Lagenorhynchus acutus ), the northern bottlenose ( Hyperoodon ampullatus ), the harbor seal ( Phoca vitulina ) and the grey seal ( Halicoerus grypus ). [1]

Climate change

The effects of climate change on the Iceland Sea have been substantial and are expected to persist. Particularly worrisome for the Iceland Sea is the phenomenon of ocean acidification, which poses a significant threat to marine life. [8] There are already observable instances of rapid acidification in the Iceland Sea, where the rate of pH decline at the sea surface is higher than the global average, leading to the reduction of habitats for bivalves and numerous other organisms. [8]

Warming of the Iceland Sea has also had notable impacts on its marine ecosystem, leading to changes in the distribution and abundance of various pelagic fish species, particularly the capelin and mackerel. [8] Additionally, several benthic fish species such as the haddock and monk fish that were traditionally located along the south coast of Iceland, have extended their range being found more north, in the Iceland Sea. [8] Such changes in environmental conditions have contributed to the decrease in sea bird and seal population presence, as well as habitat alterations for certain whale species found in the Iceland Sea. [8]

Related Research Articles

<span class="mw-page-title-main">Norwegian Sea</span> Marginal sea of the Arctic or Atlantic Ocean, northwest of Norway

The Norwegian Sea is a marginal sea, grouped with either the Atlantic Ocean or the Arctic Ocean, northwest of Norway between the North Sea and the Greenland Sea, adjoining the Barents Sea to the northeast. In the southwest, it is separated from the Atlantic Ocean by a submarine ridge running between Iceland and the Faroe Islands. To the north, the Jan Mayen Ridge separates it from the Greenland Sea.

<span class="mw-page-title-main">Plankton</span> Organisms living in water or air that are drifters on the current or wind

Plankton are the diverse collection of organisms that drift in water but are unable to actively propel themselves against currents. The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales.

<span class="mw-page-title-main">Zooplankton</span> Heterotrophic protistan or metazoan members of the plankton ecosystem

Zooplankton are the heterotrophic component of the planktonic community, having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers.

<span class="mw-page-title-main">Fish migration</span> Movement of fishes from one part of a water body to another on a regular basis

Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear.

<i>Boreogadus</i> Species of fish

Boreogadus saida, known as the polar cod or as the Arctic cod, is a fish of the cod family Gadidae, related to the true cod. Another fish species for which both the common names Arctic cod and polar cod are used is Arctogadus glacialis.

<i>Sebastes norvegicus</i> Species of fish

Sebastes norvegicus, the rose fish, rock fish, ocean perch, Atlantic redfish, Norway haddock, golden redfish, pinkbelly rosefish, Norway seaperch, Scottish seaperch or bergylt, is a species of marine ray-finned fish belonging to the subfamily Sebastinae, the rockfishes, part of the family Scorpaenidae. It is found in the North Atlantic Ocean. It is a large, slow-growing, late-maturing fish and the subject of a fishery.

<span class="mw-page-title-main">Capelin</span> Species of fish

The capelin or caplin is a small forage fish of the smelt family found in the North Atlantic, North Pacific and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat a great deal of krill and other crustaceans. Among others, whales, seals, Atlantic cod, Atlantic mackerel, squid and seabirds prey on capelin, in particular during the spawning season while the capelin migrate south. Capelin spawn on sand and gravel bottoms or sandy beaches at the age of two to six years. When spawning on beaches, capelin have an extremely high post-spawning mortality rate which, for males, is close to 100%. Males reach 20 cm (8 in) in length, while females are up to 25.2 cm (10 in) long. They are olive-coloured dorsally, shading to silver on sides. Males have a translucent ridge on both sides of their bodies. The ventral aspects of the males iridesce reddish at the time of spawn.

The Northwest Atlantic Fisheries Organization (NAFO) is an intergovernmental organization with a mandate to provide scientific advice and management of fisheries in the northwestern part of the Atlantic Ocean. NAFO is headquartered in Halifax, Nova Scotia, Canada.

<span class="mw-page-title-main">Greenland Sea</span> Body of water

The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as part of the Arctic Ocean, sometimes as part of the Atlantic Ocean. However, definitions of the Arctic Ocean and its seas tend to be imprecise or arbitrary. In general usage the term "Arctic Ocean" would exclude the Greenland Sea. In oceanographic studies the Greenland Sea is considered part of the Nordic Seas, along with the Norwegian Sea. The Nordic Seas are the main connection between the Arctic and Atlantic oceans and, as such, could be of great significance in a possible shutdown of thermohaline circulation. In oceanography the Arctic Ocean and Nordic Seas are often referred to collectively as the "Arctic Mediterranean Sea", a marginal sea of the Atlantic.

<i>Calanus finmarchicus</i> Species of crustacean

Calanus finmarchicus is a species of copepod and a component of the zooplankton, which is found in enormous amounts in the northern Atlantic Ocean.

<span class="mw-page-title-main">Jan Mayen Microcontinent</span> Atlantic fragment of continental crust

The Jan Mayen Microcontinent is a fragment of continental crust within the oceanic part of the western Eurasian Plate lying northeast of Iceland. At the onset of separation between the Greenland and Eurasian plates 55 million years ago, it formed part of the eastern margin of the Greenland Plate. Propagation of a new spreading center from the Reykjanes Ridge separated this microcontinent from the Greenland Plate. For a short period it formed a microplate, until the Aegir Ridge became inactive, after which it formed part of the Eurasian Plate. The island of Jan Mayen is a much younger feature, formed of volcanic rock, built up at the northernmost tip of the microcontinent.

<span class="mw-page-title-main">Arctic Ocean</span> Ocean in the north polar region

The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately 14,060,000 km2 (5,430,000 sq mi) and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea. It has also been described as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing world ocean.

<span class="mw-page-title-main">Forage fish</span> Small prey fish

Forage fish, also called prey fish or bait fish, are small pelagic fish that feed on planktons and other small aquatic organisms. They are in turn preyed upon by various predators including larger fish, seabirds and marine mammals, this making them keystone species in their aquatic ecosystems.

<span class="mw-page-title-main">Aegir Ridge</span> Extinct mid-ocean ridge in the far-northern Atlantic Ocean

The Aegir Ridge is an extinct segment of the Mid-Atlantic Ridge in the far-northern Atlantic Ocean. It marks the initial break-up boundary between Greenland and Norway, along which seafloor spreading was initiated at the beginning of the Eocene epoch to form the northern Atlantic Ocean. Towards the end of the Eocene, the newly forming Kolbeinsey Ridge propagated northwards from Iceland, splitting the Jan Mayen Microcontinent away from the Greenland plate. As the Kolbeinsey Ridge formed, so activity on the Aegir Ridge reduced, ceasing completely at the end of the Oligocene epoch when the Kolbeinsey Ridge reached the Jan Mayen fracture zone.

<span class="mw-page-title-main">Planktivore</span> Aquatic organism that feeds on planktonic food

A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and in the past billion years; basking sharks and copepods are just two examples of giant and microscopic organisms that feed upon plankton.

The East Iceland Current (EIC) is a cold water ocean current that forms east of Greenland at 72°N, 11°W as a branch of the East Greenland Current that merges with the Irminger Current flowing southward until it meets the northeast part of Iceland. It quickly rotates in a counterclockwise direction and flows eastward along the Iceland-Faeroe Ridge before turning north and flowing into the Norwegian Sea. The EIC flows at an average rate of 6 centimeters per second, with a maximum velocity of 10 centimeters per second occurring as the current turns eastward.

<i>Thetys vagina</i> Species of tunicate

Thetys vagina, or the twin-sailed salp, is the largest known solitary species of salp and the only valid species of the genus Thetys. First described by W.G Tilesius in 1802, the species is transparent and gelatinous, making it difficult to be seen in water, which is helpful in avoiding predators. The fossil range is very recent. Other animals often mistaken for T. vagina are Salpa fusiformis, Aurelia aurita, and Pegea confoederata. There is no known status of conservation in this species. T. vagina DNA was sequenced as part of a larger project in 2014 where spiny lobster larvae were found attached to T. vagina and consuming it.

<span class="mw-page-title-main">Nordic Seas</span>

The Nordic Seas are located north of Iceland and south of Svalbard. They have also been defined as the region located north of the Greenland-Scotland Ridge and south of the Fram Strait-Spitsbergen-Norway intersection. Known to connect the North Pacific and the North Atlantic waters, this region is also known as having some of the densest waters, creating the densest region found in the North Atlantic Deep Water. The deepest waters of the Arctic Ocean are connected to the worlds other oceans through Nordic Seas and Fram Strait. There are three seas within the Nordic Sea: Greenland Sea, Norwegian Sea, and Iceland Sea. The Nordic Seas only make up about 0.75% of the world's oceans. This region is known as having diverse features in such a small topographic area, such as the mid oceanic ridge systems. Some locations have shallow shelves, while others have deep slopes and basins. This region, because of the atmosphere-ocean transfer of energy and gases, has varying seasonal climate. During the winter, sea ice is formed in the western and northern regions of the Nordic Seas, whereas during the summer months, the majority of the region remains free of ice.

<span class="mw-page-title-main">Lipid pump</span>

The lipid pump sequesters carbon from the ocean's surface to deeper waters via lipids associated with overwintering vertically migratory zooplankton. Lipids are a class of hydrocarbon rich, nitrogen and phosphorus deficient compounds essential for cellular structures. This lipid carbon enters the deep ocean as carbon dioxide produced by respiration of lipid reserves and as organic matter from the mortality of zooplankton.

<span class="mw-page-title-main">Marine food web</span> Marine consumer-resource system

A marine food web is a food web of marine life. At the base of the ocean food web are single-celled algae and other plant-like organisms known as phytoplankton. The second trophic level is occupied by zooplankton which feed off the phytoplankton. Higher order consumers complete the web. There has been increasing recognition in recent years that marine microorganisms.

References

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