Optical assessment of large marine particles: development of an imaging and analysis sytem for quantifying large particle distributions and fluxes. Annual report, 1992-1993

摘要

The central goal of DOE's Ocean Margin Program (OMP) is to determine whether continental shelves are quantitatively significant in removing carbon dioxide from the atmosphere and isolating it via burial in sediments or exporting it to the open ocean (Program Announcement, 1991). A major component of the OMP will be to measure carbon flux on the shelf and across the shelf to the slope and open ocean. We are developing a video and optical instrument package (LAPS: Large Aggregate Profiling System) and the analytical techniques to precisely measure a wide spectrum of the large aggregate population of particles in the shelf/slope environment. This particle population, encompassing the ''marine snow'' size particles (diameters > 0.5 mm), is thought to be the major pathway of material flux in the ocean (McCave, 1975; Asper, 1987; Walsh and Gardner, 1992). Our goal is to use aggregate abundance and size spectrum data along with the CTD, beam attenuation and fluorescence data collected with our instrument package to collect data rapidly, repeatedly and accurately such that it is both linkable to carbon flux and usable in biophysical models. Additionally, measurements of particle flux will be made with sediment traps deployed on the continental slope in conjunction with the physical oceanography program. The combination of profiles and sections of aggregate data along with the measured mass flux and chemistry from the sediment traps will allow for a robust estimate of the mass transport and flux of organic carbon via the aggregate pathway. The LAPS will be tested in the field area during a cruise in June/July 1994. Sediment traps will also be deployed on that cruise to make the first comparisons between measured flux and aggregate abundance in the field area. Efforts to streamline the image processing have resulted in a suite of programs to handle data from capture to binned data. 5 refs.