WHAT THE EVIDENCE SAYS
A long-term Chaetoceros muelleri experiment compared an abrupt CO₂ increase with a gradual rise from roughly 440 to 1,000 ppm across more than 1,100 generations. Abrupt exposure generated stronger growth, carbon-fixation and genomic responses than the gradual trajectory, which more closely represents the rate of environmental change.
WHY IT MATTERS / OUR READ
The rate at which an experimental stressor is imposed is part of the treatment. Results based on abrupt step changes can overstate particular organismal responses when the real environment changes more gradually.
CAVEATS / UNCERTAINTY
This is one marine diatom species in a long laboratory experiment. It does not show that all ocean-acidification effects are overestimated, and translation from culture responses to food webs or carbon cycling remains uncertain.
SOURCE
Nature Communications
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