Tiny phytoplankton produce much of the world's oxygen.

Scientists measured phytoplanktonic pigments in sediment cores to reconstruct past ocean productivity.

Coastal ecosystems depend on phytoplanktons as the foundation of their food webs.

After unusually warm weather and nutrient runoff, a dense phytoplankton bloom spread along the coast, reducing oxygen levels and harming marine life.

Recent satellite data reveal widespread phytoplankton blooms off the continental shelf, causing oxygen depletion in some regions.