Scientists Discover How Carbon is Stored in the Southern Ocean
A team of British and Australian scientists has discovered an important method of how carbon is drawn down from the surface of the Southern Ocean to the deep waters beneath.
This latest finding was reported in the Journal Nature Geoscience which was done by scientists from British Antarctic Survey (BAS) and Australia's national research agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
The study reveal that rather than carbon being absorbed uniformly into the deep ocean in vast areas, it is drawn down and locked away from the atmosphere by plunging currents a thousand kilometres wide.
Like Us on Facebook
Eddies are the term given to the winds, currents and massive whirlpools that carry warm and cold water around the ocean, create a localized pathways or funnels for carbon to be stored.
Lead author, Dr Jean-Baptiste Sallée from British Antarctic Survey says, "The Southern Ocean is a large window by which the atmosphere connects to the interior of the ocean below. Until now we didn't know exactly the physical processes of how carbon ends up being stored deep in the ocean. It's the combination of winds, currents and eddies that create these carbon-capturing pathways drawing waters down into the deep ocean from the ocean surface. Now that we have an improved understanding of the mechanisms for carbon draw-down we are better placed to understand the effects of changing climate and future carbon absorption by the ocean."
CSIRO co-author, Dr Richard Matear says the rate-limiting step in the anthropogenic carbon uptake by the ocean is the physical transport from the surface into the ocean interior.
"Our study identifies these pathways for the first time and this matches well with observationally-derived estimates of carbon storage in the ocean interior," Dr Matear says.
Will the help of small robotic probes known as Argo floats; the scientists were able to learn the workings of the ocean. Back in 2002, the researchers had used 80 floats in Southern Ocean to collect information on temperature and salinity.
This unique set of observations spanning 10 years has enabled scientists to investigate this remote region of the world for the first time. The floats are just over a metre in length and dive to depths of 2km. Today, there are over 3,000 floats in the oceans worldwide providing detailed information used in oceanic climate models.
According to CSIRO, the team also analysed temperature, salinity and pressure data collected from ship-based observations since the 1990s, using a CTD profiler - a cluster of sensors which takes measurements as it is lowered deep down into the ocean to depths of more than 7km.