Free vehicle instrumentation for the in situ measurement of processes controlling the formation of deep-sea ferromanganese nodules

This paper describes the free vehicle instrumentation under development for the Manganese Nodule Program (MANOP) of the International Decade for Ocean Exploration (IDOE). Principal emphasis is being placed on the MANOP Bottom Lander, a device designed to carry out in situ chemical flux experiments at the seawater-sediment interface at depths up to 6 km. This device will collect time-series water samples from three separate bottom chamber experiments, each of which can be spiked with various chemical and radioisotopic tracers. The device will also make oxygen and pH measurements in each chamber and will take box core samples under each chamber before returning to the surface. All operations will be microprocessor-controlled with data storage capability and with an acoustic data-link to the surface. Deployments will be for periods of up to 1 year.