Predators suppress freshwater carbon dioxide emissions, reports a study published online this week in Nature Geoscience. The findings suggest that future changes in the diversity and abundance of predators could have consequences for freshwater carbon cycling.

Trisha Atwood and colleagues manipulated levels of predatory fish and invertebrates in a number of experimental freshwater systems in Canada and Costa Rica, and monitored carbon dioxide emissions. They found that carbon emissions were much lower in the presence of predators in all systems, despite differences in predator type, climate and ecological zone.