JR224: Chemosynthetic life in the Antarctic


 JR224



Cruise diary


Tuesday 10 February 2009
Location: Kemp Seamount (59º40'S - 28º10'W)

Incredible life in a crater by Kemp seamount

Today we have gone back to Kemp seamount, that we explored a few days ago. The swath survey has revealed the presence of a feature that was unknown until now: a large crater. We have conducted a CTD survey and have found very good signals of plumes, so there must be hydrothermal activity in this area! After the CTD, we deployed SHRIMP for a survey of the crater's seafloor. We started around the centre of the crater and the first environment we saw was seafloor covered with fine sediment covered with transparent pink sea cucumber (holothurians) everywhere, as well as two other less abundant species of holothurians, shirmp and deep-water fishes. After a while we arrived to an area with black basalt rocks that were completely covered with white brittle stars (ophiuroids). The density of these ophiuroids was incredible! On the rocks we also saw anemones and brisingid sea stars, which extend their tentacles and arms up in the water column to feed by catching the particles transported by the currents.

The discovery of this crater and its fauna has been unexpected and spectacular. We will be coming back next year with the ROV to map the crater in detail and sample the animals, so we can describe the ecosystem, explain why there are so many sea cucumbers and brittle stars and understand better their biology and the role they play in the crater habitat, in relation to the habitats surrounding the crater and Kemp seamount.

 

Very large numbers of ophiuroids on the basalt rocks

A brisingid sea-star on a rock covered with brittle stars, with its arms up in the water column to catch the particles transported by the currents on which it feeds

Large number of pink holothurians on the sediment

An anemone on a rock


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