Using a space-based laser, NASA has managed a close look and monitoring of the largest marine migration known to humankind, and the direct impact it has on the global climate. The 10-year-long study was carried out using an earth-observation satellite managed jointly by American and French national space agencies: Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO).
Researchers from NASA and the French space agency Centre National d’Etudes Spatiales (CNES) used CALIPSO’s laser capabilities to track the movement and behavior of small aquatic animals like squids and krill, from hundreds of kilometers in space. They looked specifically at a natural, daily phenomenon that involves zooplankton.
Zooplankton — a group of tiny organisms drifting in oceans, seas, and bodies of freshwater — feed on phototrophic plankton (photoplankton), and together form the base of the entire aquatic food chain. Zooplankton find their way to deep water in the morning and rise as the sun sets — a process known as the ‘diel vertical migration’, or DVM. This process is carried out all over the world by both marine and freshwater plankton.
So far, it was thought that the DVM was a compromise between finding morsels near the surface, and avoiding turning into tasty morsels for predators themselves.