Fig1b

The global atmospheric concentration of CO2 has increased dramatically since pre-industrial values, mainly through fossil fuel burning and deforestation. 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 longwave radiation and thus warms the atmosphere. Of the approximately 3 billion tonnes of carbon dioxide (CO2) pumped into the atmosphere annually by human activities, less than 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 marine 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. Despite this however, the Southern Ocean remains one of the most understudied and least-understood, places on Earth.

This is why the Centre for Scientific and Industrial Research (CSIR) has set up the Southern Ocean CO2 Observatory (SOCO), 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 Aghulhas 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 other biogeochemical measurements, so that we can better understand the link between the variability in the CO2 flux in the Sourthern Ocean and the physical and biological mechanisms that are responsible for it.

Plankton: An astonishing diversity visible from under a microscope

Plankton: An astonishing diversity visible from under a microscope

The way the Southern Ocean mops up CO2 is two fold. The first is a physical pump and is because the waters of the Southern Ocean are cold and dense and CO2 is 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 cold water to return to the surface sooner than it should. Part of SOCO’s initiative is to monitor these changes and the effect that they have on the ability of the Southern ocean to take up CO2.

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 and climate system research.

Fig1b

The global atmospheric concentration of CO2 has increased dramatically since pre-industrial values, mainly through fossil fuel burning and deforestation. 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 longwave radiation and thus warms the atmosphere. Of the approximately 3 billion tonnes of carbon dioxide (CO2) pumped into the atmosphere annually by human activities, less than 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 marine 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. Despite this however, the Southern Ocean remains one of the most understudied and least-understood, places on Earth.

This is why the Centre for Scientific and Industrial Research (CSIR) has set up the Southern Ocean CO2 Observatory (SOCO), 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 Aghulhas 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 other biogeochemical measurements, so that we can better understand the link between the variability in the CO2 flux in the Sourthern Ocean and the physical and biological mechanisms that are responsible for it.

Plankton: An astonishing diversity visible from under a microscope

Plankton: An astonishing diversity visible from under a microscope

The way the Southern Ocean mops up CO2 is two fold. The first is a physical pump and is because the waters of the Southern Ocean are cold and dense and CO2 is 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 cold water to return to the surface sooner than it should. Part of SOCO’s initiative is to monitor these changes and the effect that they have on the ability of the Southern ocean to take up CO2.

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 and climate system research.

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