Ocean gliders provide first long-term data sets in Southern Ocean

Setting off into Table Bay on a beautiful morning with two gliders strapped securely to the UCT rubber duck

As an oceanographer I jumped at the opportunity to help some colleagues deploy a pair of ocean gliders in Table Bay.

A group of oceanographers and technicians from the University of Cape Town (UCT) and the Council for Scientific and Industrial Research (CSIR), led by Dr Sebastiaan Swart, set off into Table Bay on a beautiful morning with two R1.5 million gliders strapped securely to the UCT rubber duck.

Ocean gliders are fairly new, autonomous instruments designed to record continuous measurements of ocean temperature, salinity, oxygen, light and chlorophyll a, from the surface to a depth of 1 000 metres. Gliders follow a dive route set by glider pilots, surfacing every few hours to send data back to scientists.

The stability, buoyancy and data quality of these two gliders needed to be tested, so that if all went well, they could be deployed in the Southern Ocean and left to collect data for around six months.

Once we were a few kilometres offshore, in water deeper than 70 metres, the gliders were slowly lowered into the ocean where they bobbed about with the seals until commanded to dive. Both gliders proved to be fit and ready for their Southern Ocean mission.

Understanding how climate change will affect global marine systems

The data that the gliders collect in the Southern Ocean are invaluable. Gliders are providing the first long-term data sets in the Southern Ocean, as the harsh conditions of the region make research cruises and data collection expensive and limited. These long-term data sets are allowing marine scientists to begin to understand the seasonal cycle of the Southern Ocean, which is a vital part of understanding how climate change will affect global marine systems.

The Southern Ocean takes up approximately a third of the CO₂ we put into the atmosphere, so any small changes in this oceanic CO₂ sink may have serious consequences for the global carbon cycle, ocean acidification and climate change.

For further information on the glider project, have a look at this article in the Mail and Guardian.