This project represents the balance of support required for studies related to time-series sediment trapping in the Sargasso Sea and for assuring continuation of the work beyond the present P.I.'s full-time involvement. The proposed work has two primary objectives: (1) A major portion of the effort will be spent on identifying relationships between surface-ocean variables and deep- ocean carbon flux. The marine biota is thought by many investigators to play an important part in the removal of carbon from the atmosphere and upper ocean to the deep ocean through the production of organic and carbonate particles which sink out of the mixed layer. There is, however, a considerable range in estimates of the effectiveness of this mechanism, the "biological pump", relative to the amounts of carbon dioxide injected into the atmosphere by human activities. An assessment of the magnitude, variability and secular trend of the pump is thus desirable. Direct measurement of deep-ocean carbon flux is far too expensive and labor-intensive to be done on a large scale over extended periods. However, there is a distinct possibility that much more easily monitored surface-ocean properties may serve as proxies for deep carbon flux. To test this hypothesis, this study will investigate whether or not carbon flux varies in a consistent relationship to variations in one or a combination of several of those surface properties. Identification of suitable proxies may permit long-term monitoring of the deep carbon flux on large scales. Comparative studies of existing time series of remote- sensing, meteorologic, and hydrographic data on one hand and of deep carbon-flux data on the other are a promising approach. The emphasis in such studies will be on other-than-annual periods because the annual cycle, common to all likely proxy candidates, is of little value in revealing causative connections. Comparisons will be made between continuous deep carbon-flux measurements in the Sargasso Sea and a superior variety of hydrographic and meteorologic data sets, as well as satellite data, for the area. While the Sargasso Sea is representative of only one of several major oceanographic domains which are likely to have different characteristic proxies and proxy-carbon flux relationships, the ability to assess carbon flux by means of proxies even in part of the ocean can free resources for more intensive in-situ studies in other areas. (2) Present modeling efforts at determining means and time variances of the source areas and paths of particles collected by sediment traps at different depths, i.e. using real and model current vectors in the sampling area to delineate the shapes of the statistical funnels connecting the traps to the sea surface, will be completed.
