DESIGN AND EVALUATION OF A SWIMMER-SEGREGATING PARTICLE INTERCEPTOR TRAP

A particle interceptor trap designed to segregate ''swimmers'' from sinking particles collected by the trap is described, and an evaluation of its effectiveness is presented. The trap was deployed at two coastal and two open-ocean sites. Most swimmers were effectively segregated from the sinking particles in the coastal environments (> 70% exclusion efficiency for all copepods), but segregation was weak at an open-ocean 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 from the swimmer-segregating trap and more conventional trap designs showed little difference. The trap, when effective in segregating swimmers, can be used for resolving the release of dissolved compounds by the sinking material and by the swimmers. This feature of the trap was tested in Monterey Bay, where inclusion of dissolved organic C in the total organic C material collected increased that value by 7%, while inclusion of dissolved organic N and ammonium increased the estimate for nitrogen collected by 17%.