DESIGN AND EVALUATION OF A SWIMMER-SEGREGATING PARTICLE INTERCEPTOR TRAP

A particle interceptor trap designed to segregate ''swimmers'' from si nking particles collected by the trap is described, and an evaluation of its effectiveness is presented. The trap was deployed at two coasta l and two open-ocean sites. Most swimmers were effectively segregated from the sinking particles in the coastal environments (> 70% exclusio n efficiency for all copepods), but segregation was weak at an open-oc ean site (37-72% efficiency for copepods). In general, the larger and more mobile the swimmers, the more effectively were they directed into the swimmer collection chamber. Carbon and nitrogen flux estimates fr om the swimmer-segregating trap and more conventional trap designs sho wed little difference. The trap, when effective in segregating swimmer s, can be used for resolving the release of dissolved compounds by the sinking material and by the swimmers. This feature of the trap was te sted in Monterey Bay, where inclusion of dissolved organic C in the to tal organic C material collected increased that value by 7%, while inc lusion of dissolved organic N and ammonium increased the estimate for nitrogen collected by 17%.