Plankton may help oceans to soak up twice as much carbon

Vast blooms of plankton could be enabling the ocean to absorb twice as much carbon from the atmosphere as thought, helping to slow the rate of global warming, a study has found.

Microscopic marine algae called phytoplankton live on or near the ocean’s surface and use photosynthesis to turn light into energy, consuming carbon dioxide and releasing oxygen.

When phytoplankton die the carbon they contain can sink to the ocean floor. They are also eaten by zooplankton, tiny animals whose faeces and dead bodies also create what is known as marine snow: detritus containing carbon which falls to the bottom of the sea.

Scientists at the Woods Hole Oceanographic Institution in Massachusetts said that the efficiency of this process in removing and storing carbon had been “drastically underestimated”.

They realised that the depth of the sunlit area where photosynthesis occurs, the euphotic zone, varied significantly throughout the ocean. Phytoplankton’s ability to take up carbon depends on the amount of sunlight able to penetrate the ocean’s upper layer.(thetimes)