In continued efforts to improve observations that will help scientists to understand the precise links between climate and the carbon cycle in the most southern waters of the world's oceans, the CSIR's Marine Robotics programme has deployed the first robotics platform in the Southern Ocean that combines both wave and buoyancy-driven seagliders.

This pioneering project - undertaken as part of the CSIR-led Southern Ocean Carbon Climate Observatory (SOCCO) programme - is largely funded by the Department of Science and Technology. It is implemented in partnership with the National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory and the Applied Physics Laboratory at the University of Washington in the United States of America; and locally, Sea Technology Services, the South African Maritime Safety Association and the South African National Antarctic Programme.

These deployments, over 1 000 km south-west of Cape Town, build on the pioneering work from 2012 when the CSIR completed the longest high resolution missions in the Southern Ocean using five buoyancy gliders. This new integrated fleet will be on a five- to six-month mission that will take both units to the Antarctic pack-ice and back at a crucial period when there are currently no ship-based observations in place.

According to the CSIR's Ocean Systems and Climate research group leader, Dr Pedro Monteiro, these latest deployments are unique in that they are the first global deployments of robotics-based carbon dioxide (CO2) observations in the Southern Ocean and secondly, it signals the start of a multi-platform strategy that will hopefully close the uncertainty gap in the global annual CO2 flux estimates within three years.

"These deployments are a great leap towards aiding us in generating a more accurate understanding of the link between climate and the carbon cycle in the ocean. Combined with global coupled models, this will allow us to understand the intricate relationship of the ocean and atmosphere processes and how these regulate the carbon cycle and ultimately the earth's climate. It also underlines the important role of the Southern Ocean in global and regional climate," he explains.

The deployed liquid robotics wave glider is designed to ride on the ocean surface using the vertical movements of ocean waves to propel it forward. It has specialised instruments on board that measure CO2, the ocean acidity, and other physical variables of the surface ocean. The data generated are sent via satellite communications and viewed in real-time by climate scientists back at the CSIR. The buoyancy-driven seaglider dives between the surface and a depth of 1 km. As the glider moves through the water column, it collects valuable data that describe the physics (such as temperature, salinity and the amount of light penetrating into the surface waters) and biogeochemistry such as phytoplankton and oxygen concentrations of the ocean. These data are transmitted via satellite every time the glider comes back to the surface. Both gliders are fully controlled by pilots back on land who guide their navigation and activity.

The mission coordinator, the CSIR's Dr Sebastiaan Swart, explains the significance of the dual deployment, "For the first time, we are deploying a wave glider in the Southern Ocean, but of more significance to climate researchers, we have twinned it with a seaglider that dives below the wave glider. This will allow us acquire valuable information from both gliders in an integrated approach, but more importantly, this means we can link CO2 flux between the ocean and the atmosphere at the surface ocean with understanding of the connected physical and biogeochemical processes that are occurring below the surface and in the ocean interior."

In 2012, the CSIR launched five buoyancy seagliders which were retrieved in February and March this year. The data from these gliders are currently being analysed by a number of Master's and doctoral students at the CSIR and the University of Cape Town. The first scientific papers are ready to be submitted for publication in international journals. Engineering students from the Cape Peninsula University of Technology have also been employed to complete their in-service training and obtain scarce skills from this highly advanced type of marine engineering and robotics technology. This contributes to the CSIR's HCD goals and skills generation.

The CSIR aims to continue building observational expertise through this technology "We plan to deploy another set of these gliders in December this year on the SA Agulhas II during its annual voyage to Antarctica so that we can expand our observational coverage. We will be hard at work analysing these data for new discoveries and exposing them in the international climate research domain," states Swart.

Monteiro lauded the mission team for a job well done amid unexpected challenges. "Apart from the normal complexities of this kind of technology, we had to contend with the impacts of the government shutdown in the USA. I particularly want to highlight the overall coordination role of Dr Sebastiaan Swart working with some of South Africa's the best ocean robotics engineers in Derek Needham and Andre Hoek and their new students Sinekhaya Bilana and JP Smit. This team is rapidly becoming one of the best-skilled global robotics teams with special experience in Southern Ocean conditions and constraints," he says.