The export of organic carbon from the surface ocean by sinking particles is an important, yet
highly uncertain, component of the global carbon cycle. Here we introduce a mechanistic assessment of the
global ocean carbon export using satellite observations, including determinations of net primary production
and the slope of the...
Nonlinear mesoscale eddies can influence biogeochemical cycles in the upper ocean through vertical and horizontal advection of nutrients and marine organisms. The relative importance of these two processes depends on the polarity of an eddy (cyclones versus anticyclones) and the initial biological conditions of the fluid trapped in the core...
Submarine volcanic eruptions can result in both real and apparent changes in marine algal communities, e.g., increases in phytoplankton biomass and/or growth rates that can cover thousands of square kilometers. Satellite ocean color monitoring detects these changes as increases in chlorophyll and particulate backscattering. Detailed, high resolution analysis is needed...
Global ocean phytoplankton biomass (C-phyto) and total particulate organic carbon (POC) stocks have largely been characterized from space using passive ocean color measurements. A space-based light detection and ranging (lidar) system can provide valuable complementary observations for C-phyto and POC assessments, with benefits including day-night sampling, observations through absorbing aerosols...
Satellite measurements allow global assessments of phytoplankton concentrations and, from observed temporal changes in biomass, direct access to net biomass accumulation rates (r). For the subarctic Atlantic basin, analysis of annual cycles in r reveals that initiation of the annual blooming phase does not occur in spring after stratification surpasses...
Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems
and contributes roughly half of the Earth's net primary production. For 13 years, the Sea-viewing Wide
Field-of-view Sensor (SeaWiFS) mission provided the first consistent, synoptic observations of global ocean
ecosystems. Changes in the surface chlorophyll concentration, the primary...
Reconciling rates of organic carbon export from the euphotic zone with the consumption of organic material in the dark ocean remains one of the major quantitative uncertainties of the ocean carbon cycle. Euphotic zone net community production (NCP) provides one broad constraint on export flux and potential carbon drawdown. However,...
The fluorescence signal emitted from phytoplankton exposed to natural sunlight has been considered a potentially useful tool to examine phytoplankton physiology from in situ radiometers and satellites, but variability in the fluorescence signal is confounded by non-photochemical quenching (NPQ). This pathway dissipates excitation energy as heat rather than fluorescence. It...
Global increases in ultraviolet-B radiation (UVBR) have the potential to alter marine primary production and to affect carbon cycles and marine trophic dynamics. Estimates of UVBR induced photoinhibition have varied greatly, indicating that a common dose-response by marine phytoplankton may not occur from place to place. An action spectrum describing...
The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that
vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a
critical depth horizon defining the point where phytoplankton growth exceeds losses. This
hypothesis has since served as a cornerstone in plankton ecology and reflects the...