A free vehicle for measuring benthic community metabolism1

Abstract

A free vehicle respirometer (FVR) which measures the oxygen consumption of benthic communities in situ to abyssal depths consists of a structural aluminum tripod supporting a two‐command acoustic release‐transponder, an oxygen monitoring unit, a glass sphere flotation array, and a time lapse camera system. An acoustic signal actuates the first command mode. This releases the oxygen monitoring unit. Settlement is monitored by the camera system. After measurements lasting 1 to 5 days, the second acoustic command releases the descent weight, and the free vehicle is brought to the surface by the flotation array and recovered. Preliminary results obtained with the FVR at 5,200 in in the northwest Atlantic suggest that benthic community respiration decreases three orders of magnitude from values measured at shallow shelf depths.