JR224: Chemosynthetic life in the Antarctic


 JR224



The JR224 cruise on RRS James Clark Ross



This research cruise on board the British Antarctic Survey ship the RRS James Clark Ross is attempting 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. 

Deep-sea scientists are trying to find missing pieces of the global puzzle that may explain to us why we see these “biogeographic” patterns, or in other words, patterns of where different animals live on our planet.  No-one has ever explored Antarctic vents and seeps for animal life before so this is a very exciting venture indeed.  Will the scientists find animals that are similar to those that live in the Atlantic, in the Pacific, or both oceans? Perhaps they will find that the vents and seeps around the Antarctic Ocean may act as stepping stones for vent and seep animals from the Pacific to reach the Atlantic vents and vice versa.  Or will they discover some entirely new species that have never been seen before? Perhaps they will find species that have evolved in these waters in complete isolation from all other vent and seep species? Will there be similar species between the four different sites that they intend to examine in Antarctic waters? (see map, left).

Left: Map showing the areas of study during the cruise

As well as looking to see what animals (of all sizes) live at these sites, scientists will also investigate the fluids coming from the vents and seeps to see their temperatures, and the concentrations of the elements that they contain.  Many of the animals from vents and seeps have symbiosis (relationship of mutual benefit) with microorganisms, which use the energy from sulphides and methane that come from these fluids to produce organic matter in a process called chemosynthesis.  Scientists will look at how much energy animals are using from these chemicals and how much from food sources falling from the surface waters.  They will study the food webs for these deep-dwelling animals.

Another aspect that these oceanographic scientists will look at is the patterns of current flow around the sites to see if they can relate these patterns to the animals they find.  They may find, for example, that some vent or seep animals are able to hitch a ride on the currents so that they are able to colonise new or different sites. 

These are very exciting times for the marine scientists on board – and many more (including you!) who await the outcome of these investigations. 

This cruise is the first of 3 cruises that are planned for this ChEsSo project.  We hope you will follow them all.  In case you are wondering about the name of this project, 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 in 2010, so look out for that!

The ChEsSo cruises will employ the use of some of the latest technologies for exploring the deep ocean.  On this first cruise the scientists aim to locate the vent and seep sites by using existing evidence of plumes found during previous exploration.  Their first mission will be to make 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 can calculate how deep the water is and any obstacles present. A colour map of the seafloor can then be 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.

An instrument called BRIDGET will then be deployed from the ship.  BRIDGET will have a series of sensors incorporated so that it can detect any hydrothermal plume that may be present. Once a plume has been located, the scientists will deploy an instrument called a CTD is used to measure the conductivity and temperature of the water, as well as being able to take water samples at different depths. This will enable scientists to have an even more precise idea of the location of the origin of the plume. Finally, the scientists will use SHRIMP, a piece of equipment with video and still photo cameras, to take the first images of the hydrothermal vents and cold seeps and the animals that live there.

The map shows where the scientists will be doing their research on the cruises.  The institutions that are involved in the ChEsSo Project are: National Oceanography Centre, Southampton; British Antarctic Survey, Cambridge; Zoological Society of London; Woods Hole Oceanographic Institution, USA; Portugal and Spain?  You can read more about the team here.


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