Icebergs photographed from the MV SA Agulhas in Antarctica

Icebergs photographed from the MV SA Agulhas in

The global atmospheric concentration of carbon dioxide (CO2) has increased by more than 40% since pre-industrial values of 270ppm to 387ppm in 2010, mainly through fossil fuel burning and land use changes. Present-day CO2 levels are now higher than at any time in the past 650,000 years. The reason we care about this increase in CO2 is because of concerns over climate change.

CO2 is a greenhouse gas which means that it absorbs outgoing long wave radiation and in so doing warms the atmosphere. Of the approximately 3 billion tonnes of CO2 pumped into the atmosphere annually by human activities, about half stays there, warming the planet through the greenhouse effect. The rest is soaked up by natural processes, more-or-less evenly divided between land and oceans. Of the ocean half, by far the biggest portion (50%) is taken up by the Southern Ocean. The Southern Ocean is thus disproportionately more important when it comes to buffering the impacts of climate change through increasing atmospheric CO2 concentrations. There are however serious consequences to the delicate ecosystems that are performing this earth system service, such as ocean acidification in the polar oceans. Perhaps an even more serious long term consequence, is that the large but natural ocean-atmosphere CO2 flux in the Southern Ocean, which up until now has been in balance, may be changing in response to climate-driven adjustments in the westerly winds. Changes in the coupled carbon – climate system have the potential of positive feedbacks that could weaken and even nullify the effectiveness of CO2 emission reduction targets. This poorly understood link between carbon and climate is not only one of the greatest challenges to the oceanography community but also an important contribution by science, including South African science, to the well being of the planet. Despite this however, the Southern Ocean remains one of the most understudied and least-understood places on Earth. South Africa has a comparative geographic advantage, as well as an established presence in Antarctica which it can use to make a strong impact on these pressing questions and at the same time address its need for highly skilled scientists and engineers.

One of the main aims of the research carried out on these cruises is to perform a long time series of measurements of CO2 gas flux in the Southern Ocean

This is why the Council for Scientific and Industrial Research (CSIR), in collaboration with groups from the University of Cape Town, Stellenbosch and Marine Coastal Management (MCM), have set up the Southern Ocean Carbon and Climate Observatory (SOCCO), whose research initiative is to better understand the role of the Southern Ocean in the future climate of our planet. A part of the research takes advantage of the annual voyages of South Africa’s polar research vessel the MV SA Agulhas to Marion Island, Gough Island and the SANAE base in Antarctica. One of the main aims of the research carried out on these cruises is to perform a long time series of measurements of CO2 gas flux in the Southern Ocean together with numerous biogeochemical measurements that will allow us to better understand the link between the variability in the CO2 flux in the Southern Ocean and the physical and biological mechanisms that are responsible for it. Our ability to develop and investigate these system scale questions was significantly enhanced from 2009 by the support from the Department of Science and Technology (DST) through a capital infrastructure investment that in three phases is allowing us to build a world class observational capability. This capability includes the purchase of autonomous platforms such as state of the art underwater sea gliders and profiling floats. In addition, the South African Department of Environmental Affairs have commissioned a new R1.3 billion Polar Supply and Research Vessel that is being constructed in a shipyard in Finland and is due to arrive early next year. The value of observations collected from the ship and the autonomous platforms are enhanced several fold by linking them to both satellite observations and numerical modelling studies which allow us to understand the changes on time and space scales that do not depend on the ship alone.

The way the Southern Ocean mops up CO2 is two fold. The first is a physical pump that results form the waters of the Southern Ocean being cold and dense and CO2 being highly soluble in cold water. As the cool, heavy waters rich in CO2 move northwards, they sink below the warmer lighter subtropical waters taking CO2 out of the atmosphere and into the deep waters for centuries. But what if this circulation pattern is disrupted by climate change itself? That is what seems to be happening – a shift in the wind regime above the Southern Ocean is causing more cold deep water to return to the surface sooner than it should. Part of SOCCO’s initiative is to observe and understand these changes, the effect that they have on the ability of the Southern ocean to take up CO2 , and its consequences to the changing global carbon-climate system.

The second mechanism of carbon adsorption is provided by the ‘biological pump’, whereby tiny algal cells called phytoplankton take up CO2 through photosynthesis. When these plants die they sink to the ocean floor taking carbon with them. Despite the bitter cold and winter darkness, the Southern Ocean is highly productive in the spring and summer months when there is sufficient sunlight and certain key nutrients (especially iron and silica) to promote their growth. Our annual research cruises to Antarctica are trying to understand why this productivity is so restricted in time and place, and how the role of the biological carbon pump will adjust to a future change in climate. A team of oceanographers on board make measurements of both the physical and chemical environment that the phytoplankton cells live in so that they can understand what controls their growth in the Southern Ocean.

The global significance of these oceanographic research efforts in the Southern Ocean is clear. South Africa is extremely well-positioned to undertake Antarctic research and with continued efforts in obtaining relevant and high quality data, we hope to be an internationally recognised group in polar, climate, carbon and ecosystem research. The benefits are not only that we use our science to strengthen South Africa’s global citizenship but also to provide a flagship to support the prioritisation of high skills education in support of development.

 

  • Incubations: Oceanographic scientists Samantha Maxwell-Hafen (left) and Fiona Preston-Whyte (right) incubating water samples for phytoplankton primary production measurements on board the MV SA Agulhas in Antarctica.
  • SA-AgulhasSouth Africa's Antarctic resupply vessel the MV SA Agulhas in bay ice in Antarctica
  • SANAE 49 Team: Top left: Ceinwen Smith, Samantha Maxwell-Hafen, Dr Yuri Cotroneo, Dr Bob Scholes, Patrick Hayes-Foley. Middle left: Dr Sandy Thomalla, Amy Harington, Sarah-Anne Nicholson, Thato Mtshali. Front: Fiona Preston-Whyte
  • Sunset: A sunset over icy seas photographed from the MV SA Agulhas in Anarctica
Icebergs photographed from the MV SA Agulhas in Antarctica

Icebergs photographed from the MV SA Agulhas in

The global atmospheric concentration of carbon dioxide (CO2) has increased by more than 40% since pre-industrial values of 270ppm to 387ppm in 2010, mainly through fossil fuel burning and land use changes. Present-day CO2 levels are now higher than at any time in the past 650,000 years. The reason we care about this increase in CO2 is because of concerns over climate change.

CO2 is a greenhouse gas which means that it absorbs outgoing long wave radiation and in so doing warms the atmosphere. Of the approximately 3 billion tonnes of CO2 pumped into the atmosphere annually by human activities, about half stays there, warming the planet through the greenhouse effect. The rest is soaked up by natural processes, more-or-less evenly divided between land and oceans. Of the ocean half, by far the biggest portion (50%) is taken up by the Southern Ocean. The Southern Ocean is thus disproportionately more important when it comes to buffering the impacts of climate change through increasing atmospheric CO2 concentrations. There are however serious consequences to the delicate ecosystems that are performing this earth system service, such as ocean acidification in the polar oceans. Perhaps an even more serious long term consequence, is that the large but natural ocean-atmosphere CO2 flux in the Southern Ocean, which up until now has been in balance, may be changing in response to climate-driven adjustments in the westerly winds. Changes in the coupled carbon – climate system have the potential of positive feedbacks that could weaken and even nullify the effectiveness of CO2 emission reduction targets. This poorly understood link between carbon and climate is not only one of the greatest challenges to the oceanography community but also an important contribution by science, including South African science, to the well being of the planet. Despite this however, the Southern Ocean remains one of the most understudied and least-understood places on Earth. South Africa has a comparative geographic advantage, as well as an established presence in Antarctica which it can use to make a strong impact on these pressing questions and at the same time address its need for highly skilled scientists and engineers.

One of the main aims of the research carried out on these cruises is to perform a long time series of measurements of CO2 gas flux in the Southern Ocean

This is why the Council for Scientific and Industrial Research (CSIR), in collaboration with groups from the University of Cape Town, Stellenbosch and Marine Coastal Management (MCM), have set up the Southern Ocean Carbon and Climate Observatory (SOCCO), whose research initiative is to better understand the role of the Southern Ocean in the future climate of our planet. A part of the research takes advantage of the annual voyages of South Africa’s polar research vessel the MV SA Agulhas to Marion Island, Gough Island and the SANAE base in Antarctica. One of the main aims of the research carried out on these cruises is to perform a long time series of measurements of CO2 gas flux in the Southern Ocean together with numerous biogeochemical measurements that will allow us to better understand the link between the variability in the CO2 flux in the Southern Ocean and the physical and biological mechanisms that are responsible for it. Our ability to develop and investigate these system scale questions was significantly enhanced from 2009 by the support from the Department of Science and Technology (DST) through a capital infrastructure investment that in three phases is allowing us to build a world class observational capability. This capability includes the purchase of autonomous platforms such as state of the art underwater sea gliders and profiling floats. In addition, the South African Department of Environmental Affairs have commissioned a new R1.3 billion Polar Supply and Research Vessel that is being constructed in a shipyard in Finland and is due to arrive early next year. The value of observations collected from the ship and the autonomous platforms are enhanced several fold by linking them to both satellite observations and numerical modelling studies which allow us to understand the changes on time and space scales that do not depend on the ship alone.

The way the Southern Ocean mops up CO2 is two fold. The first is a physical pump that results form the waters of the Southern Ocean being cold and dense and CO2 being highly soluble in cold water. As the cool, heavy waters rich in CO2 move northwards, they sink below the warmer lighter subtropical waters taking CO2 out of the atmosphere and into the deep waters for centuries. But what if this circulation pattern is disrupted by climate change itself? That is what seems to be happening – a shift in the wind regime above the Southern Ocean is causing more cold deep water to return to the surface sooner than it should. Part of SOCCO’s initiative is to observe and understand these changes, the effect that they have on the ability of the Southern ocean to take up CO2 , and its consequences to the changing global carbon-climate system.

The second mechanism of carbon adsorption is provided by the ‘biological pump’, whereby tiny algal cells called phytoplankton take up CO2 through photosynthesis. When these plants die they sink to the ocean floor taking carbon with them. Despite the bitter cold and winter darkness, the Southern Ocean is highly productive in the spring and summer months when there is sufficient sunlight and certain key nutrients (especially iron and silica) to promote their growth. Our annual research cruises to Antarctica are trying to understand why this productivity is so restricted in time and place, and how the role of the biological carbon pump will adjust to a future change in climate. A team of oceanographers on board make measurements of both the physical and chemical environment that the phytoplankton cells live in so that they can understand what controls their growth in the Southern Ocean.

The global significance of these oceanographic research efforts in the Southern Ocean is clear. South Africa is extremely well-positioned to undertake Antarctic research and with continued efforts in obtaining relevant and high quality data, we hope to be an internationally recognised group in polar, climate, carbon and ecosystem research. The benefits are not only that we use our science to strengthen South Africa’s global citizenship but also to provide a flagship to support the prioritisation of high skills education in support of development.

 

  • Incubations: Oceanographic scientists Samantha Maxwell-Hafen (left) and Fiona Preston-Whyte (right) incubating water samples for phytoplankton primary production measurements on board the MV SA Agulhas in Antarctica.
  • SA-AgulhasSouth Africa's Antarctic resupply vessel the MV SA Agulhas in bay ice in Antarctica
  • SANAE 49 Team: Top left: Ceinwen Smith, Samantha Maxwell-Hafen, Dr Yuri Cotroneo, Dr Bob Scholes, Patrick Hayes-Foley. Middle left: Dr Sandy Thomalla, Amy Harington, Sarah-Anne Nicholson, Thato Mtshali. Front: Fiona Preston-Whyte
  • Sunset: A sunset over icy seas photographed from the MV SA Agulhas in Anarctica
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