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Rare creatures from the deep
Scientists from a number of research institutions, including the National Oceanography Centre, have just returned from a voyage with samples of rare animals and more than 10 new species in a trip which they say has revolutionised their thinking about deep sea life in the Atlantic Ocean.
The scientists spent six weeks in the Atlantic aboard the RRS James Cook.
Using the latest technology they saw species in abundance that hitherto had been considered rare.
Researchers were also surprised to discover such diversity in habitat and marine life in locations just a few miles apart.
Scientists were completing the last leg of MAR-ECO - an international research programme, part of the Census of Marine Life, which is enhancing our understanding of the occurrence, distribution and ecology of animals along the Mid-Atlantic Ridge between Iceland and the Azores.
The University of Aberdeen is leading the UK contribution to project which involves scientists from 16 nations.
During more than 300 hours of diving - by a remotely operated vehicle to depths of between 700m right down to 3,600m - researchers surveyed flat plains, cliff faces and slopes of the giant mountain range that divides the Atlantic Ocean into two halves, east and west.
The research was focused in two areas - beneath the cold waters north of the Gulf Stream and the warmer waters to the south.
Professor Monty Priede, Director of the University of Aberdeen’s Oceanlab, said: “We were surprised at how different the animals were on either side of the ridge which is just tens of miles apart.
“In the west the cliffs faced east and in the east the cliffs faced west. The terrain looked the same, mirror images of each other, but that is where the similarity ended. It seemed like we were in a scene from Alice Through the Looking Glass.
“In the north-east, sea urchins were dominant on the flat plains and the cliffs were colourful and rich with sponges, corals and other life.
“In the north-west, the cliffs were dull grey bare rock with much less life. The north-west plains were the home of deep sea enteropneust acorn worms. Only a few specimens, from the Pacific Ocean, was previously known to science.
“The creatures were observed feeding and leaving characteristic spiral traces on the seafloor.
“They have no eyes, no obvious sense organs or brain but there is a head end, tail end and the primitive body plan of back-boned animals is established. One was observed showing rudimentary swimming behaviour.
“By the end of the expedition three different species were discovered with each with a different colour, pink, purple and white with distinctly different shapes.”
Using the remotely operated vehicle, high quality complete specimens of all three species, pink, purple and white were captured and will be sent to specialists for further investigations
Sea cucumbers, or holothurians, normally seen crawling incredibly slowly over the flat abyssal plains of the ocean floor, were found on steep slopes, small ledges and rock faces of the underwater mountain range.
Researchers were also surprised to see that they were very able and fast moving swimmers and unique video sequences were recorded of swimming holothurians.
Professor Priede said: “This expedition has revolutionised our thinking about deep sea life in the Atlantic Ocean. It shows that we cannot just study what lives around the edges of the ocean and ignore the vast array of animals living on the slopes and valleys in the middle of the Ocean.
“Using new technology and precise navigation we can access these regions and discover things we never suspected existed.”
Dr Andrey Gebruk, Shirshov Institute, Moscow, said: “We were surprised how species, elsewhere considered rare, were found in abundance on the Mid Atlantic Ridge and we were finding new species up to the last minute of last dive in the voyage.”
Dr Daniel Jones, National Oceanography Centre, Southampton, surveyed over 50,000 square meters of sea floor in high definition detail and said “ We successfully completed one of the most detailed video surveys of the deep sea ever attempted. The ISIS ROV with its cutting-edge technology gives us the potential to understand more and more of the mysterious deep sea environment”
ThThis work was funded by the UK Natural Environment Research Council as the ECOMAR project (www.oceanlab.abdn.ac.uk/ecomar/) and is a contribution tothe Census of Marine Life (http://www.coml.org/) programme MARECO (http://www.mar-eco.no). This was the last in a series of fofour annual voyages undertaken since 2007 investigating all aspects of life over the Mid Atlantic Ridge.
