Although most drifting buoys start their journeys with a crude send-off—usually heaved into the ocean from the stern of a moving ship—NOAA oceanographer Rick Lumpkin describes today's drifter as "a high-tech message in a bottle."  Insignificant on their own, but an army of drifters 1,000 strong patrols the world's oceans and records key data for climate monitoring and research.

Scientists can now remotely monitor the ocean’s changing chemistry with help from some of the five-foot-tall Argo floats that drift with deep ocean currents and transmit data via satellite back to...