A high resolution marine particle analysis system

Suspended particulate matter is a primary variable with respect to biological and physical processes in the marine environment. The authors have developed an integrated towed instrument platform system to analyze as broad a spectrum of particulate sizes as possible using state-of-the-art technology to address basic oceanographic, environmental and military issues. The High Resolution Sampler (HRS) system uses several technologies to address different size classes of the marine particle spectrum. The 50 μ to 2 cm (spherical diameter, SD) size classes are quantified using Optical Plankton Counters (OPC, Focal Technologies, Inc.), employed alone or in tandem. The 50 μ and greater size classes are also quantified using a non-intrusive laser light sheet/video system as well as a collimated dual light sheet system under development. As an alternative to optical systems, the authors are developing a multiple frequency, miniaturized forward-looking “chirp” sonar for ensonifying a parcel of water directly ahead of the light sheet (see Remsen et al., this volume). All data are collected in situ and transferred to deck for real-time display and storage. Verification systems include a plankton cod-end (50-162 μ mesh) carousel (20 positions) net system for collecting particles which have passed through the optical sensors. The integrated optical-electronic sensor package is mounted on a towed vehicle which has been sea tested over several years in the Gulf of Mexico and Weddell Sea