In the last six weeks, we have been exploring five seamounts of the South West Indian Ocean Ridge.
The expedition took place on board the RRS James Cook (U.K. Natural Environment Research Council research vessel). 54 persons were on board made up of crew, scientists, and technicians.
We found that the five seamounts are very different in terms of their size, their topography, their fauna and their diversity and abundance of marine life. Even the characteristics of their surrounding waters are different. We have witnessed evidence of human impacts on all of them.
‘Coral’ seamount was certainly the most preserved and richest in life. ‘Melville’ and ‘Midde-of-What’ were seamounts that show us two faces of these deep-sea habitats: one very rich, beautiful and with a diverse fauna, and the other quite devastated, with trawl marks and fishing gear on the bare seabed. ‘Sapmer’ was the seamount where we saw the fishing boat actively trawling. Most of the seabed has been damaged by trawling there, and we saw a lot of evidence of human activities on the seafloor, but inaccessible areas of the seamount still supported abundant life. On ‘Atlantis’ we saw a lot of urchins, and also giant coral trees. Some parts have been fished but the rocky seabed makes it more difficult for trawlers to work these areas. We saw patches of extremely rich fauna on rocks next to areas covered with debris and coral rubble. The top of the seamount, which is really flat, was mostly barren.
We can now count ourselves among a privileged few that have seen live images of these incredible features 1,000m and more below the surface of the oceans in that cold, dark and silent realm.
Amongst other wonders, we have seen beautiful and extremely elegant sea-spiders, 6-gilled sharks, big bamboo corals, bright pink shrimps, pencil urchins, snow white sea stars, escaping lobsters, coral gardens, tethered red jellyfish, purple coral with snake sea stars on it, angry looking crabs, fly-trap anemones, delicate glass sponges with their associated shrimp in couples, funny looking big eyes fish.… and the list goes on.
Let us not forget the spectacular images of the hydrothermal vents and some bellowing black smoke from their tall chimneys – simply amazing (see blog post 27 Nov).