Nature.com: “Marine phytoplankton — the vast range of tiny algae species accounting for roughly half of Earth’s total photosynthetic biomass — have declined substantially in the world’s oceans over the past century, researchers report in Nature this week. The findings add to concerns that climate change is dangerously altering marine ecosystems. Phytoplankton are the basis of the entire marine food chain, and have an important role in the global carbon cycle. Through photosynthesis, they produce around half of the oxygen in Earth’s atmosphere and drive the ‘biological pump’ that fixes 100 million tonnes of atmospheric carbon dioxide a day into organic material, which then sinks to the ocean floor when the phytoplankton die, or are grazed and digested.”