parameters described under 1-5, and the hydrodynamic parameters determined by physical 

 oceanographic programs, calculate the fluxes of colloidal organic carbon from the continental 

 margin to the open ocean, in particular for the colloids in the benthic nepheloid layer. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



1) Near-shore/off-shore transects, combined with 2 along-shore transects (with sampling as a 

 function of distance and as a function of depth) for sampling of dissolved, colloidal and 

 particulate radioactive and stable isotopes, colloids, pigments, lignin-phenols, DOC, SPM. 2) 

 200-800 m water depth: Sediment trap and Alabaster Lander deployment. 



METHODS AND PLATFORMS 



During field expeditions, hydrographic surveys using CTD, fluorometry and 

 transmissometry casts are carried out. Water samples are collected for radiochemical, chemical 

 and biochemical analyses, and samples are analyzed in the lab; in addition, lab experiments to 

 study the resuspension of colloids are continued. Methods include the following: 



MIPS : Multiple In-situ Pumping System for obtaining vertical profiles of radioisotopes. 



Ultrafiltration : Large-volume Cross-flow Ultra filtration, which allows us to obtain 100-1000 mg 



freeze-dried colloids from 200-1000 liters of sea water, after diafiltration of the concentrate. 



Sediment traps : Large-area, swimmer-repellent multi-sampling sediment traps will be used for 



the purpose of collecting enough sinking particulate organic carbon material to be deployed for 



>4 days. 



Alabaster Lander for Benthic Boundary Layer measurements: u* and D/z or bottom stress by 



gypsum dissolution, deployed for 0.5-2 days. 



Radioisotope measurements : 234 Th: Analysis by gamma-counting. 232 Th: Analysis by Mass 



Spectrometric methods. 230 Th: Analysis by Secondary Ion Mass Spectrometric methods fSIMSj 



Elemental analysis : by ICP-MS and standard methods (for C, N). 



DOC : Our methods have been intercalibrated with those employed in R. Benner's laboratory, 



with satisfactory agreement to within a few %. 



POC&SPM from suspended matter: Laboratory of J. Brooks for POC. 



5' 3 C : A working relationship has been established with the Lab of L. Cifuentes. 



Nutrients, oxygen : On shipboard from discrete water samples, using Technicon AA-II 



autoanalyzer. 



Total Pigments : In-situ fluorometry. Plant pigment compounds (carotenoids and chlorophylls) are 



analyzed using reverse-phase HPLC. 



Lignin-phenols are analyzed using capillary GC. Loliolides are analyzed using normal phase 



HPLC. 



A 14 C : Colloids are processed for 14 C targets by S. Trumbore, under a subcontract, and analyzed 



by J. Southon, Lawrence Livermore National Laboratory. 



Vertical profiles of Th isotopes ( 234 Th, 232 Th, 23c Th and 22& Th), oxygen, nutrients, fluorometry and 



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