Carbon dioxide measurements

Looking out across the Southern Ocean near Antarctica, I can see whales and seabirds diving in and out of the water as they feed on sea life in the lower levels of the food web. At the base of this food web are tiny phytoplankton – algae that grow at the ocean surface, taking up carbon from the atmosphere through photosynthesis, just as plants on land do. Because of their small size, phytoplankton are at the mercy of the ocean’s swirling motions. They are also so abundant that the green swirls are often visible from space. Typically, phytoplankton remain near the surface of the ocean. Some may slowly sink to depth because of gravity. But in the turbulent Drake Passage, a 520-mile-wide (850 km) bottleneck between Antarctica and South America, something unusual is happening, and it has an impact on how the ocean takes carbon dioxide – the main driver of global warming – out of the atmosphere. A satellite image capt...