Strong westerly winds of the roaring 40s and furious 50s latitudes mix atmospheric CO2 into the Southern Ocean where phytoplankton assimilate the carbon into their bodies. Dead phytoplankton sink, taking carbon to the deep ocean. This makes the Southern Ocean an enormous carbon reservoir. Recently, a southerly shift to the westerly wind belt has caused an increase in upwelling of carbon-rich deep water, releasing CO2 back to the atmosphere. The shifting wind has also caused a decrease in rainfall in southern New Zealand.
The Southern Ocean is part of a global system – the Global Ocean Conveyor. This is a system of deep currents that carry heat, salt and nutrients around the planet.
What impacts do you think this increased upwelling of carbon will have on the animal life in and around the Subantarctic Islands? What impacts might it have on climate around the Subantarctic Islands, New Zealand and the world?
Acknowledgement: Sir Peter Blake Trust.