Ocean flux studies: A status report

Abstract

Marine biogenic cycles play a key role in controlling atmospheric CO2 concentrations. To predict future atmospheric CO2 levels and to interpret past changes that may have been associated with global climatic events, it is necessary to determine on a global scale the rates at which carbon is cycled through the ocean and the factors that may alter the rates of transfer. Because of uncertainties and limitations in existing measurement techniques and the extreme spatial and temporal variability of ocean properties and processes, studies have not yet produced an accurate, comprehensive description of the marine carbon cycle. While some advances in the measurement of specific components of the carbon cycle have been made, the fundamental problem of undersampling an extremely heterogeneous ocean has remained. Recently, satellite‐deployed sensors have provided large‐scale, nearly synoptic images of ocean surface water properties, such as temperature and color, which have revealed mesoscale features not observed previously. In addition, moored and free‐drifting observation systems are being developed to determine directly the temporal variability of surface and subsurface water characteristics. With these remotely sensed properties to provide the space and time framework by which individual measurements of ocean processes and material fluxes can be extrapolated throughout ocean basins and over decadal time scales, we are poised to make a fundamental improvement in our understanding of ocean elemental cycles.