SESSION SUMMARY : BENTHIC-PELAGIC COUPLING 



Marsh Youngbluth 



Harbor Branch Oceanographic Institution 



5600 Old Dixie Highway 



Fort Pierce, FL 34946 



Particulate organic materials (POM) are major food resources 

 that can sustain marine food chains on the sea floor and in the 

 water column. Two research groups, one from the Harbor Branch 

 oceanographic Institution (HBOI) and one consisting of scientists 

 from the Louisiana Universities Marine Consortium (LUMCON) , the 

 Bigelow Laboratory for Ocean Sciences (BLOS) , and the University 

 of Maine (UM) , collaborated to make comprehensive measurements of 

 the distribution, amount and flux of POM in order to permit 

 predictions about the biological, chemical, and physical 

 processes that affect POM accumulation, transport, and 

 utilization. Specifically, the occurrence, density and 

 composition of large (fecal pellets from zooplankton, HBOI) and 

 small ( LUMCON/ BLOS/UM) particulate matter within the water column 

 and near the sea floor were related to environmental 

 discontinuities, mixed layer productivity and decomposition- 

 dissolution processes. Submersibles (JOHNSON-SEA-LINK and DELTA) 

 and conventional water bottles were used to selectively sample 

 particles at water mass boundaries as well as the sediment/water 

 interface. In addition, collections gathered with moored and 

 free-drifting sediment traps provided estimates of daily POM flux 

 rates. The information gathered should enhance the 

 interdisciplinary mode of the Benthic Productivity Program in the 

 Gulf of Maine. For example, knowledge of POM flux rates will 

 contribute to understanding the patterns of distribution, 

 abundance and survival among suspension feeders and deposit 

 feeders. 



Data from the HBOI group indicated that vertically sinking 

 fecal pellets from a single euphausiid species Meqanvctithanes 

 norvegica can transport substantial amounts of organic matter to 

 the bottom. Furthermore, vertically migrating populations of 

 this krill, which feed on resuspended particulate material in the 

 epibenthic nepheloid layer, may reintroduce such material into 

 the mixed layer. Information from the LUMCON/ BLOS/UM group 

 revealed that particulate matter from the mixed layer and the 

 nepheloid region were protein-rich. Biologically available 

 protein in these two regions was 84 and 21% of the total protein, 

 respectively. 



Two of the most sophisticated devices developed to date to 

 sample the fluff layer are described in Mayer et al. Future 

 investigations of particulate materials will require 

 the utilization of additional sampling devices that can be 



179 



