234Th and particulate fluxes in the Kara Sea in October 1993

The mean residence time of 234Th associated with suspended matter in the Kara Sea was calculated from distributions of dissolved and suspended 234Th. Integral particulate fluxes at different levels were estimated for two stations. The flux increases only in the pycnocline; below it changes insignificantly. Two maxima of differential fluxes are noted in vertical profiles: in the surface layer where primary production is maximal, and in the interface layer where zooplankton realizing active transport of suspended matter is usually concentrated. Differential fluxes were determined at 10 stations; their space distribution is controlled by primary production, which depends usually on turbidity of river water in estuaries.