MOCNESS

Last month I participated in an oceanographic research cruise near the Barbados Accretionary Prism. My job was to help with the MOCNESS (Multiple Opening/Closing Net and Environmental Sensing System), which is a net system used to sample plankton. The MOCNESS can collect independent plankton samples at specific depth intervals during a single deployment, this is accomplished by independently opening and closing the nets.

The MOCNESS has a rectangular frame that houses the environmental sensing system and controls the nine nets (MOCNESS can have between 6 and 20 nets). The cable connects the ship and MOCNESS and gives scientists real-time data so instrument adjustments can be made during sampling. The sensors were used to collect salinity, temperature, depth, and water flow measurements. We used 153 µm mesh nets and the speed of the MOCNESS through the water averaged 10m/min so that the small ciliated larvae would not get damaged. 

The pictures are of the MOCNESS after it had been recovered. The first image (taken by Svetlana Maslakova) is the science team transferring the samples from the cod ends to containers for sorting. The second image (taken by Svetlana Maslakova) is of myself and another graduate student setting up the nets in preparation for the next tow. The third image is a sample that was collected in one of the cod ends. We conducted nine MOCNESS tows, depths of the samples ranged from the surface to 4500 meters. These tows will allow us to look at the vertical distribution of deep sea larvae. 

Wiebe, P. H., K. H. Burt, S. H. Boyd and A. W. Morton. 1976. A multiple opening/closing net and environmental sensing system for sampling zooplankton. Journal of Marine Research 34:313-326

Wiebe, P. H., A. W. Morton, A. M. Bradley, R. H. Backus, J. E. Craddock, V. Barber, T. J. Cowles and G. R. Flierl. 1985. New developments in the MOCNESS, an apparatus for sampling zooplankton and micronekton. Marine Biology 87:313-323