Rising global temperatures could prompt some streams to release more carbon dioxide than they do now, exacerbating climate change.
As their environment warms, algae and microbes living in streams photosynthesize faster and absorb more CO2 from the air. But they also grow faster, releasing extra CO2.
To calculate the net impact of such changes, Chao Song at the University of Georgia in Athens and his colleagues monitored the temperature, dissolved oxygen level and other traits of 69 streams around the world. They then folded the data into computer models.
The models suggest that, over time, the rising rate of photosynthesis in some streams will not keep pace with plant growth, leading to a net release of CO2. If this pattern is scaled up, a 1 °C rise in global temperatures could result in a net 24% increase in carbon released from streams worldwide.
Nature 557, 615 (2018)