A globally important phytoplankton, coccolithophore Emiliania huxleyi, is able to evolve to cope with the changing marine environment, reports a paper published online in Nature Climate Change. These results show that phytoplankton niches may be more evolutionarily flexible than previously thought.

Emiliania huxleyi plays an important role in the global carbon cycle by storing carbon dioxide. Thorsten Reusch and colleagues studied its long-term evolution by looking at adaptations to ocean temperature increases and declining ocean pH (ocean acidification). The phytoplankton were tested at three different dissolved carbon dioxide concentrations and two temperatures - 15 degrees Celsius and 26.3 degrees Celsius. The authors report that cells evolved over the course of one year to a smaller size in response to increased water temperature, with lower carbon content per cell. However, warm-adapted cells had higher biomass production - a 52% increase for organic carbon and 101% for inorganic carbon.

The flexibility of phytoplankton highlights that evolutionary processes should be considered in projections of climate change impacts on them.