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Setting a Trap

Marine chemist Ken Buesseler examines a neutrally buoyant sediment trap (NBST), while engineer Jim Valdes looks on. Buesseler and Valdes conceived and developed these free-floating devices to sink to a pre-programmed depth and then hold their position in the ocean without sinking or rising. NBSTs are swept along with the currents for several days (as much as 10-20 miles), collecting dying plankton, fecal pellets, and other particles that sink out of the upper ocean. After a time, the sediment traps resurface, transmit their position via satellite, and wait for recovery. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)