ChEss Cruise Explores the East Scotia Ridge for Life at Black Smokers
RRS James Cook black smoker expedition to the East Scotia Ridge
The Biogeography of Deep-Water Chemosynthetic Ecosystems (ChEss) program is set to explore areas of the deep seabed of the Southern Ocean to locate and investigate hot water vents (hydrothermal vents) and cold seeps. Vents and seeps have already been found in the Pacific (in 1977), Atlantic (1984), Indian (2000) and in the Arctic Ocean (2001). Scientists have discovered that these deep, cold and highly toxic systems are home to many bizarre animals. They have also noticed that some of the most dominant animals in one vent or seep habitat may differ significantly from another vent or seep. For example, the giant tubeworms, Riftia pachyptilla, are found in some Pacific vents but have never yet been found to live around vents in the Atlantic, Indian or Arctic Oceans.
This cruise is the second in the ChEsSo programme. ChEsSo stands for ChEss in the Southern Ocean. ChEss is one of the deep sea programmes to do with hydrothermal vents, cold seeps and whale falls, within the Census of Marine Life – a global network of researchers in more than 80 countries undertaking a 10 year scientific initiative to study the diversity, distribution and abundance of life in our oceans. The world’s first comprehensive Census of Marine Life – past, present and future – will be released later in 2010.
The ChEsSo cruises will employ the use of some of the latest technologies for exploring the deep ocean. On the first cruise the scientists located the vent and seep sites by using existing evidence of plumes found during previous exploration. They produced a precise bathymetric map of the seafloor using a sound source to send sound waves from the ship, through the water column to the seabed, where the sound waves bounce off the seafloor. The reflected waves are then detected by the sonar equipment on board the ship and by using the amount of time it takes for the signal to return, the onboard computer calculates how deep the water is and any obstacles present. A colour map of the seafloor was then produced using these data. The exact position of the ship is determined using a GPS, and this is important in creating representative bathymetric maps. Also, the rolling, pitching, and heave of the ship must be taken into account. Detectors are used so that the influence these have on the results can be measured.
On this expedtion the scientists will be using Isis, the UK’s deep-diving remotely operated vehicle (ROV). Isis is capable of working at depths of 6000 metres. On this cruise it will be working at depths of 2800 metres using high definition cameras to record the animals living in these habitats.
