PRINCIPAL 

 INVESTIGATOR(S) 



Both at: 



Peter H. Santschi and Mahalingam Baskaran 



Department of Marine Science 

 Texas A&M University 

 Galveston, TX 77553 



Thomas Bianchi 



Center for Coastal and Marine Studies 



Department of Biology 



Lamar University 



Beaumont. TX 77710 



Bruce Honeyman 



Environmental Science & Engineering 

 Colorado School of Mines 

 Golden, CO 80401 



PROJECT TITLE 



THE PRODUCTION OF COLLOIDS IN THE BENTHIC 

 BOUNDARY LAYER AND PARTICLE-PARTICLE 

 INTERACTIONS 



AMOUNT OF FUNDING FY 1994: $262 K 



SUMMARY OF GOALS 



H Characterize the colloidal material extracted from lkD, 3 kD and lOkD ultrafiltration 

 cartridges by measuring concentrations of thorium (such as ^^Th, 232 Th, 230 Th) and carbon 

 isotopes (such as 5 l3 C, A 14 C), selected chemical biomarkers (such as plant pigments, 

 lignin-phenols. and loliolides), trace elements (such as Al, Fe and Pb), and acid/base properties. 

 2) Investigate the relationships between chemical, biochemical (pigment and lignin-phenol 

 biomarkers) and isotopic composition and residence times of colloidal organic carbon produced 

 on the continental margin off Cape Hatteras. 3) Reconcile the apparent discrepancy between old 

 apparent 14 C age of DOC and COC in the ocean and short turnover times of fractions of the DOC 

 pool, using radiochemical and biochemical approaches. 4) Determine relationships between 

 dissolved and particulate Th scavenging rate constants and particle or DOC concentrations along 

 near-shore/off-shore gradients. 5) Determine relationships between water column fluxes and 

 resuspension rates of COC and POC, dissolved and particulate scavenging rate constants of Th 

 nuclides and the nature of colloids in the water column. 6) Determine the relationships between 

 hydrodynamic parameters in the water column and sediment resuspension rates of colloidal 

 organic carbon in controlled microcosm and/or flume experiments. 7) Using the geochemical 



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