Diving to the depths of the equatorial Atlantic

An international team of researchers headed out to sea from Tenerife last Sunday to explore the deep-sea corals of the equatorial Atlantic Ocean. The scientists left on the British research vessel James Cook and will reach their final destination in Trinidad at the end of November.

Among the mass of technological equipment aboard the ship is an ISIS remotely-operated vehicle that will enable the team to study depths of the ocean never explored before. The underwater robot is highly manoeuvrable and is controlled by an operator on the ship.

The vehicle is equipped with sonars, cameras, manipulators and instruments to measure water clarity, light penetration and temperature. By measuring past and present ocean chemistry, the scientists will be able to assess its impact on fragile deep-sea ecosystems.

The team, headed by British scientist Dr Laura Robinson, will collect and analyse samples of corals, seawater and sediments along the route.

Robinson said oceans were a key part of the world’s climate system and variations in the circulation of heat, carbon and nutrients in their water masses were likely to affect global climate change.

Funded by the European Research Council, the team includes oceanographers, geochemists and marine biologists. They will be studying modern and fossil corals, trying to better understand their habitats, ecology and chemistry, and to fill the gaps in current knowledge of oceanic history.

The James Cook is equipped with five scientific and control laboratories to meet the needs of the researchers and provide for the use of specialist geochemical techniques. The crew will work 12-hour shifts to allow for constant operation of the laboratories and to maximise productivity.

Robinson said one of the innovative aspects of the research would be using skeletons of deep-sea corals for analysis and to match them with seawater and sediment samples in a single programme.

The combination of ship-board field work, modern calibrations and cutting-edge geochemical analyses, would help the team produce relevant samples and data, she said.

“My goal is to understand the dynamics and connections between the deep ocean and the climate in the past, and how these changes have impacted fragile marine ecosystems. For instance, many species of deep-sea corals have skeletons which are susceptible to degradation by ocean acidification.”

Marine research held clues to determine the cause of local extinction and repopulation events, she said: “During our cruise, we will explore the impact of temperature, salinity and nutrient supply on these corals and we hope to provide new insights into deep-sea oceanography, including the processes involved in abrupt climate change, past and present.”

Robinson said the ISIS robot was a “fantastic piece of equipment” which would allow the team to take precision samples and to conduct experiments at depths unreachable by human divers.