IN-SITU TRACER STUDIES OF SOLUTE TRANSPORT ACROSS THE SEDIMENT-WATER INTERFACE AT THE BERMUDA TIME-SERIES SITE

In situ tracer experiments have been utilized to assess the rates of t ransport of solutes across the sediment-water interface in the deep se a at the Bermuda Time Series site. The site lies some 83 km southeast of Bermuda, an environment considered to be representative of an oligo trophic gyre. Transport has been evaluated on the basis of release of NaBr into benthic chambers and determinations of Br- losses from the c hambers as well as Br- profiles and inventories in the sediments recov ered in the chambers. The experiments provide no evidence of transport across the sediment-water interface in excess of that expected for di ffusion alone. The sensitivity of our analysis to variations in transp ort rate places a limit on non-diffusive transport of less than or equ al to 25% of diffusive transport.