either absorb or scatter light in shelf waters (e.g. Case II waters). We plan to continue to 

 evaluate the performance of this instrument in an upcoming cruise to the waters off of Cape 

 Hatteras. 



STATUS OF RESEARCH 



To date, we have completed 2 research cruises in the Gulf of Mexico shelf waters off of 

 Louisiana. In addition, we will be participating on the upcoming R/V Gyre cruise to the Cape 

 Hatteras study region (June 27-July 12, with Drs. P. Santschi, R. Jahnke, L. Benninger and I. 

 Walsh). 



The Gulf of Mexico work involved collaboration with Drs. R. Benner, M. Dagg and S. 

 Strom. We explored the production, assimilation and fate of organic carbon in the Louisiana 

 shelf waters of the northern Gulf of Mexico. We found out that recycling of carbon through 

 both the micro- and macrozooplankton represented major losses of particulate organic carbon. 

 Much of this carbon was transformed from particulate to dissolved organic forms. Bacterial 

 production rates were reasonable relative the measured rates of primary production. One 

 important finding was that the vertical export of dissolved organic carbon associated with sinking 

 particles collected in free-floating sediment traps was approximately equal the export of POC. 

 The export of DOC represents a major pathway for the loss of organic carbon from the photic 

 zone in Gulf of Mexico shelf waters. Our Gulf of Mexico results were consistent with previous 

 VERTEX findings for the North Pacific central gyre where we also found that DOC export was 

 comparable to POC export. 



Keywords: photosynthesis, primary production, satellites, POC flux 



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