Ecosystem
Ecosystem
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The ocean currents around Iceland Source: The Marine Research Institute |
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School of cod over a kelp forest in N.E. Iceland. Photo: Erlendur Bogason |
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-Cod_in_kelp_forest--(copyright-Erlendur.B).jpg)
Iceland is the second largest island in Europe, after Great Britain. It touches the Arctic Circle in the North and has maritime boundaries with Greenland in the west and north-west, Jan Mayen (Norwegian) in the north and the Faroe Islands in the south-east. The nearest neighbours are Greenland, 280 km to the northwest and the Faroe Islands, 430 km to the southeast.
The ocean around Iceland includes the boundary between warm Atlantic waters in the south and colder waters from the north. Thus, inter-annual variability in oceanic conditions is high, depending on the strength of the currents. Nevertheless, due to the warm current from the south the climate in Iceland is temperate compared to how far to the north it is located.
The Irminger current keeps the waters south and west of Iceland relatively warm and stable both inter and intra-annually. The major spawning grounds for most Icelandic fish stocks are in these waters. Most of them spawn in early spring, when the larvae are able to utilise the spring phyto- and zooplankton bloom, while they drift to nursery areas. The waters north of the country are colder and fluctuate more, both between seasons, years and decades, depending on the strength of the Irminger current versus the colder currents. The waters north of Iceland are also important rearing grounds for juveniles of many species such as capelin, herring, haddock and cod. When we go further north, the waters get even colder, but also less fluctuating. Few commercially important species live there, with the notable exceptions of northern shrimp, capelin and Greenland halibut.
The productivity of Icelandic waters is fairly high, caused both by temperature driven blending of sunlit surface waters with nutrient rich deep waters and the mixing of the cold and warm ocean currents. Although many species live around Iceland the ecosystem is dominated by rather few but very abundant species. About 25 species are of commercial importance, but only a handful dominate the catches. From these only one species has nearly always provided more than half of the export earnings for Icelandic marine products, this is the cod. In recent decades the total catches have fluctuated from 1 to 2 million tonnes per year.
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A few numerical facts about the ocean around Iceland
| Value | Unit | ||
|---|---|---|---|
| The total size of the exclusive economic zone (EEZ) | 758,000 | km2 | |
| The size of the continental shelf less than 500 m deep | 212,000 | km2 | |
| The size of the continental shelf less than 200 m deep | 111,000 | km2 | |
| Total length of the coastline | 5,000 | km | |
| Distance to nearest neighbour (Greenland) | 280 | km | |
| Threshold depth Denmark Strait | 620 | m | |
| Threshold depth Iceland-Faroe ridge | 550 | m | |
| Maximum depth in the EEZ | 3,300 | m | |
| Average primary production on the shelf | 218 | g Carbon m-2 year-1 | |
| Average primary production offshore | 151 | g Carbon m-2 year-1 | |
| Average primary production within EEZ | 160 | g Carbon m-2 year-1 | |
| Total annual primary productio, EEZ | 120 million | t Carbon year-1 |
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