The CSIR's Dr Seb Swart (in front) and the marine engineers from Sea Technology Services' Derek Needham (left) and Andre Hoek with one of Africa's first long-range ocean gliders. Relatively inexpensive platforms compared to ships, these gliders sample the upper 1 000 metres of the ocean for periods up to six months. They relay data ashore within hours of collection and can be controlled globally via the satellite to Internet relays.
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Seaglider 542 in the water, about to start its three-month journey in the Benguela current just off the west coast of South Africa. |
It has been a great start for Seaglider 542 in the southern Benguela. Deployed early in February 2012, this brand new, state-of-the-art autonomous long-range ocean glider – a first for Africa – has travelled more than 100 kilometres and completed 300 dives.
Seaglider 542 is one of two long-range ocean gliders that arrived in South Africa late last year and are the first of their kind on the continent, with some more planned for later this year.
According to Dr Sebastiaan Swart, oceanographer with the CSIR in Cape Town, long-range gliders offer a unique platform for ocean-climate observations, and represent one of the most novel technologies available in oceanography.
Funded by the Department of Science and Technology (DST), the gliders form part of a larger programme – the Southern Ocean Carbon and Climate Observatory (SOCCO) – to build South Africa’s capacity in providing high-quality, precise data related to carbon-climate interactions in the Southern Ocean.
Over the next two to three months, Seaglider 542 is expected to sample an area of about 10 000 km² while collecting measurements of temperature, salinity, oxygen and chlorophyll from the surface to the bottom of the ocean. This data will assist researchers to better understand how the Benguela region works in terms of oceanography, as well as to understand the dynamics of local ecosystems where species such as the West Coast Rock Lobster thrive, Dr Swart explains.
However, there is much more in store for the two ocean gliders. Later this year, they will go on board the SA Agulhas II, South Africa’s brand new polar research vessel arriving in May. Dr Swart, “Using the SA Agulhas II, the gliders will be deployed into the heart of the world's largest ocean current, the Antarctic Circumpolar Current, which represents one of the harshest environments on Earth. It will be the first time ever that gliders are deployed into this region of the Southern Ocean – currently the most under-sampled ocean in the world.”
Up to now, sampling of the Southern Ocean was restricted to the SA Agulhas’ annual north-south trips to Antarctica. The ocean gliders will enable researchers to expand their sampling range by thousands of kilometres and, due to their endurance, they will be collecting data from periods of the year they have never been able to sample before.
The graph shows the location of completed dives until middle February (magenta dots) within the sampling box for this mission. |
“We plan to deploy another six to eight gliders south of Gough Island later this year. The idea is to guide them via Iridium satellite communications along the major ocean fronts, until they reach the Good Hope line (south of Cape Town). They will then profile to a depth of 1 000 metres around a fixed point for three months, before being recovered by the SA Agulhas II on its return trip from Antarctica,” he says.
According to Dr Pedro Monteiro, SOCCO programme leader, these deployments form a crucial part of SOCCO's Southern Ocean Seasonal Cycle Experiment (SOSCEx) from austral spring to autumn (2012 to 2013), which will combine measurements taken from ships, gliders and floats. The experiment will include the participation of international partners from the United States, Norway and France and will be in preparation for South Africa’s participation in a planned multi-nation international experiment, beginning in 2014. This broader experiment aims to improve the global understanding of the link between the carbon cycle and climate in the Southern Ocean.
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