A5069584614- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Oceanographic and Atmospheric Processes
- Microbial Community Ecology and Physiology
- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Isotope Analysis in Ecology
- Ocean Acidification Effects and Responses
- Marine and fisheries research
- Atmospheric aerosols and clouds
- Coral and Marine Ecosystems Studies
- Atmospheric Ozone and Climate
- Algal biology and biofuel production
- Climate variability and models
- Water Quality Monitoring and Analysis
- Geology and Paleoclimatology Research
- Photosynthetic Processes and Mechanisms
- Aquatic Ecosystems and Phytoplankton Dynamics
- Air Quality Monitoring and Forecasting
- Marine and coastal plant biology
- Coastal and Marine Management
- Toxic Organic Pollutants Impact
- Marine Bivalve and Aquaculture Studies
- Oil Spill Detection and Mitigation
- Protist diversity and phylogeny
Oregon State University
2016-2025
Langley Research Center
2024
Corvallis Environmental Center
2014
Goddard Space Flight Center
2000-2013
Laboratoire d’Océanographie de Villefranche
2012
National Aeronautics and Space Administration
2003-2004
Rutgers, The State University of New Jersey
1998-1999
Carnegie Institution for Science
1998
Stanford University
1998
Carnegie Department of Plant Biology
1998
Integrating conceptually similar models of the growth marine and terrestrial primary producers yielded an estimated global net production (NPP) 104.9 petagrams carbon per year, with roughly equal contributions from land oceans. Approaches based on satellite indices absorbed solar radiation indicate marked heterogeneity in NPP for both oceans, reflecting influence physical ecological processes. The spatial temporal distributions ocean are consistent limitation by light, nutrients,...
We assembled a dataset of 14 C‐based productivity measurements to understand the critical variables required for accurate assessment daily depth‐integrated phytoplankton carbon fixation ( PP eu ) u from sea surface pigment concentrations C sat )( ). From this dataset, we developed light‐dependent, depth‐resolved model (VGPM) that partitions environmental factors affecting primary production into those influence relative vertical distribution P z and control optimal assimilation efficiency...
Ocean biogeochemical and ecosystem processes are linked by net primary production (NPP) in the ocean's surface layer, where inorganic carbon is fixed photosynthetic processes. Determinations of NPP necessarily a function phytoplankton biomass its physiological status, but estimation these two terms from space has remained an elusive target. Here we present new satellite ocean color observations (C) chlorophyll (Chl) show that derived Chl:C ratios closely follow anticipated dependencies on...
We describe a classification system for daily phytoplankton primary productivity models based on four implicit levels of mathematical integration. Depth‐integrated have appeared in the literature average once every 2 years over past decades. All these can be related to single formulation equating depth‐integrated production (∑ PP ) surface biomass (C surf ), photoadaptive variable ( P b opt euphotic depth (Z eu an irradiance‐dependent function F and daylength DL ). The difference between is...
Net primary production (NPP) is commonly modeled as a function of chlorophyll concentration (Chl), even though it has been long recognized that variability in intracellular content from light acclimation and nutrient stress confounds the relationship between Chl phytoplankton biomass. It was suggested previously satellite estimates backscattering can be related to carbon biomass (C) under conditions conserved particle size distribution or relatively stable C total particulate organic carbon....
The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than critical horizon defining the point where growth exceeds losses. This hypothesis has since served as cornerstone plankton ecology and reflects very common assumption are caused enhanced rates response improved light, temperature, stratification conditions, not simply correlated with them. Here, nine‐year satellite record of biomass...
The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides global monthly measurements of both oceanic phytoplankton chlorophyll biomass and light harvesting by land plants. These allowed the comparison simultaneous ocean net primary production (NPP) responses to a major El Niño La Niña transition. Between September 1997 August 2000, biospheric NPP varied 6 petagrams carbon per year (from 111 117 year). Increases in were pronounced tropical regions where Niño–Southern Oscillation (ENSO)...
We investigate the functioning of ocean’s biological pump by analyzing vertical transfer efficiency particulate organic carbon (POC). Data evaluated include globally distributed time series sediment trap POC flux, and remotely sensed estimates net primary production (NPP) sea surface temperature (SST). Mathematical techniques are developed to compare these temporally discordant using NPP flux climatologies. The seasonal variation is mapped shows regional‐ basin‐scale biogeographic patterns...
Abstract The export of organic carbon from the surface ocean by sinking particles is an important, yet highly uncertain, component global cycle. Here we introduce a mechanistic assessment using satellite observations, including determinations net primary production and slope particle size spectrum, to drive food‐web model that estimates zooplankton feces algal aggregates comprising flux at base euphotic zone. synthesis observations models reveals fundamentally different ecologically...
Abstract The Plankton, Aerosol, Cloud, Ocean Ecosystem (PACE) mission represents the National Aeronautics and Space Administration’s (NASA) next investment in satellite ocean color study of Earth’s ocean–atmosphere system, enabling new insights into oceanographic atmospheric responses to changing climate. PACE objectives include extending systematic cloud, aerosol, biological biogeochemical data records, making essential measurements further understand marine carbon cycles, food-web...
Abstract. Phytoplankton photosynthesis links global ocean biology and climate-driven fluctuations in the physical environment. These interactions are largely expressed through changes phytoplankton physiology, but physiological status has proven extremely challenging to characterize globally. fluorescence does provide a rich source of information long exploited laboratory field studies, is now observed from space. Here we evaluate underpinnings variations satellite-based chlorophyll...
Abstract Eddies can influence biogeochemical cycles through a variety of mechanisms, including the excitation vertical velocities and horizontal advection nutrients ecosystems, both around eddy periphery by rotational currents trapping fluid subsequent transport eddy. In this study, we present an analysis mesoscale ocean eddies on near‐surface chlorophyll (CHL) estimated from satellite measurements color. The influences advection, trapping, upwelling/downwelling CHL are analyzed in...
Nonlinear mesoscale eddies can influence biogeochemical cycles in the upper ocean through vertical and horizontal advection of nutrients marine organisms. The relative importance these two processes depends on polarity an eddy (cyclones versus anticyclones) initial biological conditions fluid trapped core at time formation. Eddies originating eastern South Indian Ocean are unique that anticyclones, typically associated with downwelling, contain elevated levels chlorophyll‐a, enhanced primary...
Ocean ecosystems play a critical role in the Earth's carbon cycle and quantification of their impacts for both present conditions predictions into future remains one greatest challenges oceanography. The goal EXport Processes from Remote Sensing (EXPORTS) Science Plan is to develop predictive understanding export fate global ocean net primary production (NPP) its implications climates. achievement this requires mechanisms that control euphotic zone as well underlying "twilight zone" where...
The measurement of phytoplankton carbon (Cphyto) in the field has been a long-sought but elusive goal oceanography. Proxy measurements Cphyto have employed past, are subject to many confounding influences that undermine their accuracy. Here we report first directly measured values from open ocean. samples were collected diversity environments, ranging Pacific and Atlantic oligotrophic gyres equatorial upwelling systems temperate spring conditions. When compared earlier proxies, direct...
The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is an interdisciplinary investigation to improve understanding of Earth's ocean ecosystem-aerosol-cloud system. Specific overarching science objectives for NAAMES are (1) characterize plankton ecosystem properties during primary phases the annual cycle their dependence on environmental forcings, (2) determine how these interact recreate each year conditions bloom, (3) resolve remote marine aerosols boundary layer clouds...
Abstract The Carbon, Absorption, and Fluorescence Euphotic‐resolving (CAFE) net primary production model is an adaptable framework for advancing global ocean productivity assessments by exploiting state‐of‐the‐art satellite color analyses addressing key physiological ecological attributes of phytoplankton. Here we present the first implementation CAFE that incorporates inherent optical properties derived from measurements into a mechanistic accurate phytoplankton growth rates ( μ ) (NPP)....