Is the Southern Ocean getting greener?

The Southern Ocean is a key player in regulating the planet's biogeochemistry, productivity, and climate. Ocean color data from two NASA satellites show statistically significant increases in the concentration of chlorophyll in all sectors of the Southern Ocean, particularly in the Sub-Antarctic Zone and Permanently Open Ocean Zone. The smallest changes were observed in the Atlantic and Pacific sectors of the Sub-Tropical Zone. These trends seem accentuated by higher chlorophyll concentrations during the austral winter. Increases in the annual and wintertime chlorophyll concentrations can have implications for the Southern Ocean biological pump and ocean productivity and higher trophic levels.

The Southern Ocean is getting greener because the amount of marine plants (phytoplankton) has been increasing in the last 21 years. These changes appear to be happening faster during the winter, which suggests that the growing season is getting longer. This is important because the Southern Ocean has a big role in the biology and chemistry of the oceans, and in regulating the Earth's climate. This work was done using 21 years of data from two NASA satellites.