What do top predators have to do with chemistry? Turns out, their presence (or lack thereof) can alter ecosystems, turning them from carbon sinks or carbon suppliers (and vice versa). Researchers from the University of British Columbia studied watery ecosystems in Canada and Costa Rica and found that, when the biggest fish were removed, carbon emissions increased. You wouldn’t expect removing the apex predator to always increase emissions, but the simple fact that those animals can have an impact on emissions at all is totally fascinating.