Underwater robots developed by researchers at Scripps Institution of Oceanography at the University of California San Diego offer scientists a remarkable new tool to study ocean currents and the tiny creatures they transport. Swarms of these underwater robots helped answer some basic questions about the most abundant life forms in the ocean - plankton. The scientists designed and built the miniature autonomous underwater explorers, or M-AUEs, to study small-scale environmental processes taking place in the ocean. The ocean-probing instruments are equipped with temperature and other sensors to measure the surrounding ocean conditions while the robots “swim” up and down to maintain a constant depth by adjusting their buoyancy. The experiment helped the researchers confirm that free-floating plankton can use the physical dynamics of the ocean - in this case internal waves - to increase their concentrations to congregate into swarms to fulfill their fundamental life needs.