STRENGTHS AND LIMITATIONS OF PROPOSED RESEARCH 



The measurements chosen in principle allow inference of benthic fluxes of reactive debris 

 (e.g., plankton C org , Si0 2 , CaC0 3 ) over monthly timescales, remineralization rates and reaction 

 pathways internal to the sedimentary deposit (N, Mn), and relative importance of physical or 

 biological control of transport processes ^^Th, x-radiographs, Br", live/dead shell analysis) at 

 a given site. The comparison of live/dead carbonate bearing infauna also provides insights into 

 biological controls on mortality (i.e., predation) as well as indicating transport processes such 

 as lateral input of debris. A major advantage of using sediments for this purpose is that they 

 provide integrated measures of net processes operating in an area, direct measurements of 

 boundary conditions associated with net burial of biogenic debris, and are less subject to the 

 high frequency and spatial variations typical of water column measurements while still 

 providing insight into nonsteady state processes. A substantial uncertainty in the present case 

 is that the chlorophyll-based models of C org flux have been derived exclusively from ongoing 

 research in Long Island Sound and may not be as successful in the Hatteras field region. The 

 sediment incubation reaction rate techniques are also best done in situ at depths > 200 - 500 m. 

 Applicability of the proposed methods will be examined during preliminary study in August 

 1994. 



STATUS OF RESEARCH 



Research to date has been based in Long Island Sound and has shown that the techniques 

 outlined above provide a coherent, quantitative depiction of material flux and transport processes 

 in bottom sediments during a spring bloom period. Initial extension of the approaches and 

 evaluation of their use in the Hatteras field region will be done during late August 1994 in 

 conjunction with R. Jahnke and L. Benninger. A submersible will be employed to obtain samples 

 within characteristically complex terrain in the study area. Results of the measurement suites 

 outlined previously will be compared with solute and burial fluxes determined by Jahnke and 

 Benninger, and act as a basis for future effort or modification thereof. 



Keywords: Biogenic fluxes, sedimentary remineralization, benthic communities 



