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The sediments penetrated on Leg 58 of the Deep Sea Drilling Project in the Philippine Sea represent long periods of geologic time during which depositional conditions apparently remained very constant.Organic carbon and nitrogen contents of the sediments decrease with increasing depth of burial, before leveling off at minimum values of about 0.05 to 0.10 per cent and 0.01 per cent, respectively. The depth at which the minimum values are reached varies from site to site, but ages of sediments corresponding to the minima are all about 5 m.y.We infer that slow bacterial diagenesis is responsible for the gradual depletion of organic carbon and nitrogen. It is likely that the rate of bacterial metabolism is controlled by the rate of diffusion of electron acceptors within the sediments.These results suggest that bacterial ecosystems in deep-water sediments play a much more important role in diagenesis than has previously been thought.

Abstract. Source control i.e. the reduction of contamination from upstream or diffuse sources, is a critical element in any management plan for contaminated waterways. If source control measures are not successfully implemented, then a situation exists in which contamination will continue through time, and the cleanup of waterway segments becomes increasingly problematic. To provide greater understanding of the issues surrounding source control, it is essential to have some knowledge of contaminant sources and transport pathways of contaminated particulates. In port areas a plethora of factors interact to control contaminant transport pathways. These include: rain and river flow; tidal circulation, surface waves and wind drift, and temporally changing water column stratification. Particle tracking offers a practical means to map the transport pathways of contaminated sediments under these collective influences. This paper introduces a new and novel "dual signature" tracer product, and describes the particle tracking technique on a practical level through a study example in the Lower Duwamish Waterway, Washington, USA.

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