Friday 4th June 2010

A little background story…

Today was a rather uneventful day.  The wind picked up again over night and we are waiting for it to calm down again.  We are continuously assessing the weather to see when we can take up work again, hopefully soon.

I will take this opportunity to give a little background to this project.  For those wondering why we are out here in the rough, continuously overcast, cold, North Atlantic, rather than back home enjoying the summer.

We have 4 study sites in the vicinity of the Charlie Gibbs Fracture Zone (CGFZ), to the southeast, southwest, northwest and northeast. This area has some pretty interesting features, such as the sub-polar front to the north of the CGFZ, which means there is warm, oligotrophic (nutrient poor) water to the south, and cold, eutrophic (nutrient rich) water to the north.  At greater depths we also have the nutrient rich, cold waters coming from the Arctic through the fracture zone.  By studying those four sites, in essence, we aim to investigate the effect the presence of the ridge, the fracture zone and the polar front have on the water flow and biological communities from the surface to the sea floor.

This is our 3rd cruise as ECOMAR.  We have 6 UK institutions that are involved, bringing different expertise to the project.  We also have international friends and collaborators on board, such as our irreplaceable Russian taxonomists from the Shirshov Institute.  Taxonomists are specialists in identifying animals (They normally specialise on certain groups and study their morphological variation and classify them according to those features.)  Our first cruise was in 2007, when we did a swath survey in order to map and understand the area and its topography better.  This was followed by heavy sampling at the sites in 2007 and also in 2009.  We mainly sampled the areas by trawling and deploying baited landers (which attract scavenging fauna, such as amphipods (e.g. Pandania sp.) and scavenging fish (e.g. Coryphaenoides sp.)).  This year we will finalise our field research by having the ROV (remotely operated vehicle) on board, which is very exciting in itself and I am sure will be discussed in more detail by one of my colleagues. 

The Isis ROV being recovered

While we gained a fairly good insight into the mobile fauna by trawling and lander deployments in previous years, the ROV will allow us to see the animals in their natural environment, without any manipulations.  It will also allow us to collect samples of those species that cannot be trawled, such as sponges and corals that are attached to hard rock substratum.  

Additionally, some of the animals we trawl up look very different when they come up, because they get damaged and loose distinct features, such as little feet.  As example, for those interested, I have attached three pictures of holothurians (in natural habitat, out of the trawling net, preserved).  Often animals lose their colour once preserved which causes them to look very different.  It really makes me very appreciative of the vast knowledge taxonomists have to have about the animals kingdom in order to be able to identify them regardless of their condition.

Holothurian photographed on sea floor

Holothurians collected with a trawl

Preserved holothurians

Claudia Alt

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