Ocean algae can evolve fast to tackle climate change – ‘Evolutionary processes need to be considered when predicting the effects of a warming and acidifying ocean on phytoplankton’Posted by Jim at Sunday, October 12, 2014
By Alister Doyle; Editing by Rosalind Russell
14 September 2014
OSLO (Reuters) – Tiny marine algae can evolve fast enough to cope with climate change in a sign that some ocean life may be more resilient than thought to rising temperatures and acidification, a study showed.
Evolution is usually omitted in scientific projections of how global warming will affect the planet in coming decades because genetic changes happen too slowly to help larger creatures such as cod, tuna or whales.
Sunday's study found that a type of microscopic algae that can produce 500 generations a year - or more than one a day - can still thrive when exposed to warmer temperatures and levels of ocean acidification predicted for the mid-2100s.
The Emiliania huxleyi phytoplankton studied are a main source of food for fish and other ocean life and also absorb large amounts of carbon dioxide, the main greenhouse gas, as they grow. Their huge blooms can sometimes be seen from space.
"Evolutionary processes need to be considered when predicting the effects of a warming and acidifying ocean on phytoplankton," according to the German-led study in the journal Nature Climate Change. (Scientific American is part of Nature Publishing Group.)
Thorsten Reusch, an author of Sunday's study at the GEOMAR Helmholtz-Centre for Ocean Research in Kiel, cautioned the findings about were only for one species of algae in a laboratory test, in water with no predators or disease.
He said it was not an argument that global warming was less serious than expected. Longer-lived creatures, from fish to shellfish, would not be able to evolve their way out of trouble. [more]
ABSTRACT: Although ocean warming and acidification are recognized as two major anthropogenic perturbations of today’s oceans we know very little about how marine phytoplankton may respond via evolutionary change. We tested for adaptation to ocean warming in combination with ocean acidification in the globally important phytoplankton species Emiliania huxleyi. Temperature adaptation occurred independently of ocean acidification levels. Growth rates were up to 16% higher in populations adapted for one year to warming when assayed at their upper thermal tolerance limit. Particulate inorganic (PIC) and organic (POC) carbon production was restored to values under present-day ocean conditions, owing to adaptive evolution, and were 101% and 55% higher under combined warming and acidification, respectively, than in non-adapted controls. Cells also evolved to a smaller size while they recovered their initial PIC:POC ratio even under elevated CO2. The observed changes in coccolithophore growth, calcite and biomass production, cell size and elemental composition demonstrate the importance of evolutionary processes for phytoplankton performance in a future ocean.