A Continuous Seafloor Sediment Sampler (CS3)
Authors: Noakes John Edward , Harding James L. 
Published: October 2008

The CS3 system consists of three subcomponents: A sediment sampler, a shipboard processor, and elemental analysis instrumentation. The sediment sampler is made up of a sled which is towed at 3 to 5 knots on the sea floor for the purpose of agitating and suspending surgical sediments. A pump, buried within the sled, pumps the suspended sediment slurry to the surface via hose connection. Aboard ship, an on-line centrifugal sediment separator allows an operator to select the desired sediment particle size prior to processing. The sample processor is fully programmable enabling the secretion of a wide range of sample sizes and frequency of connection. Sample are axiomatically processed on a continuous roll of filter paper and coded for sample identification, date and time. Sample connection can be as rapid as every 30 seconds. Elemental analysis is carried out using x-ray fluorescence (XRF). Samples can be fed directly into the XRF instrumentation allowing for multi-element analyses to be computed within minutes after the sample material arrives aboard ship. Because of the non-destructive nature of these analyses, samples can be retained for additional testing on shore.

Introduction

A need has long existed for a shipboard system capable of sampling sea-Door sediments while the survey vessel is underway and analyzing samples while still at sea. In recognition of this need and the possible applications of such a system to marine pollution studies, monitoring ocean dumping sites and marine mineral exploration, the Office of Ocean Engineering (NOAA, U.S. Department of Commerce) began funding the development of such a system in 1977. The first two years were devoted to design and fabrication and in late 1979 field tests were initiated.

The initial design was formulated by the authors in conjunction with several co-workers and was based on the concept of using pathfinder elements in marine sediments for identifying non-indigenous material. Basic to this concept is the hypothesis that the fine sediment fractions (i.e. silt and clay) of the sea floor sediments represent the ultimate sink or permanent reservoir for a large variety of organic and inorganic material injected into the marine environment.

These injections have many conduits, including atmospheric, fluvial, sub-seafloor emanations and can be natural or man-made. It was, therefore, decided that the capabilities of the system should stress the sampling of the finer sediment fraction. Coincident to this decision, it was felt that such a system should also incorporate a means for continually collecting surgical sediments while the ship was underway, thus enabling high-density profiling of the chemical constituents along a given survey tract.

In order to meet the requirements dictated by the above considerations, a rapid and non-destructive means of analytically measuring the samples while at sea was deemed mandatory. This capability would allow areas of interest to be delineated and, hence, studied in greater detail prior to the survey vessel returning to port.

Design And Development

The first two years of the program were devoted to developing the three-part system consisting of the sea floor sampler, the shipboard processor and the analytical instrumentation.