Algae blooms regularly make for pretty, swirly satellite photos of lakes and oceans. They also make the news occasionally for poisoning fish, people and other animals. What's less frequently discussed is the outsize role they play in global carbon cycling. A recent study now reveals surprising facts about carbon flow in phytoplankton blooms. Unexpectedly few bacterial clades with a restricted set of genes are responsible for a major part of the degradation of algal sugars.