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Open sea zones

The pelagic (all of the aquatic animals which occupy "the column of water") and particular benthic (organisms which live near the bottom.) biodiversity of the open sea zones around New Caledonia is still very poorly understood.

Open sea zones
However two summaries presented by Richer de Forges et al. (IRD) in 2005 and by Kitahara, MV and Cairns, (Smithsonian Instituten) in 2008 demonstrate respectively that in favour of prospection at the sea bed comprised between 200 and 1200 m around more than 50% of species discovered were totally unknown and that New Caledonia with over 160 species of "coldwater" coral possesses no doubt a diversity at least equal if not superior to that of all the other areas in the world as regards deep-sea coral communities.

Coldwater coral

Open sea zones
The ecosystems of coldwater coral, or deep-sea coral, develop the length of the continental margins at depths varying from several hundred metres to just over a thousand metres. Cold water coral is in all respects comparable with warm water coral by their three-dimensional organisation, their ecological functions and their method of growth, and provide a habitat for a community of organisms including numerous groups of invertebrates and fish. Their location along the continental margins at depths subject to fishing efforts, even petrol exploration and laying cables, as well as their high productivity, means their habitats are particularly fragile. This is why they are classified among sensitive habitats by the Ospar agreement on the protection of the marine environment of the North-East Atlantic of 2004. With few differences between tropical coral, the latter are deprived of zooxanthellae (symbiotic micro-algae). They must therefore draw their food from the surrounding water, particularly as regards suspension or dissolution in the water, but also zooplankton which polyps, animals which form coral, capture actively. However, the contribution of each of these sources to the diet of the coral remains to be discovered.

(Source Ifremer)

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