Mauritanian mounds

The Mauritanian margin can be found in the North Atlantic, off the coast of Mauritania and Senegal, where the continental shelf falls away into the depths. The Mauritanian margin is host to some of the largest cold-water coral mound provinces in the Atlantic Ocean, with some reaching heights of 100m and extending over a range of 400km. There are hundreds of mounds, arranged into large provinces. These mounds were present during the last interglacial (130,000years ago), albeit in low numbers. Over this time, they caused a large vertical build-up of sediment at 16 cm per thousand years. However, cold-water coral mound build up increased during the last glacial period (115,000 - 11,700years ago) to approximately 1000cm per thousand years. The formation of mounds then stagnated in the Holocene (11,650 years ago to present). The Mauritanian mounds seemed to experience major growth in ‘age clusters’, with growth slowing or even halting during times of unfavourable conditions. Despite this, there has been an almost continuous presence of corals along the Mauritanian ridge.


The Mauritanian mounds now remain in a dormant state with limited growth. Living cold water corals are often found in numerous submarine canyons in the region. These canyons provide a refuge to many cold water coral species, with modest recolonisation occurring along the mounds of open slopes, possibly due to changes in water mass structure. The Mauritanian margin belongs to an area of upwelling that should induce high seasonal productivity. This seems contradictory, as the corals should benefit from highly productive conditions and show high levels of growth. However, the mounds are bathed by oxygen depleted waters which can cause decreased growth rates, diminished reproduction and increased post-settlement mortality of juvenile corals.

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