Introduction to EXPORTS


Ocean ecosystems play a critical role in the Earth’s carbon cycle and the quantification of their impacts for both present conditions and for predictions into the future remains one of the greatest challenges in oceanography. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS) Science Plan is to develop a predictive understanding of the export and fate of global ocean net primary production (NPP) and its implications for present and future climates. The achievement of this goal requires a quantification of the mechanisms that control the export of carbon from the euphotic zone as well as its fate in the underlying “twilight zone” where some fraction of exported carbon will be sequestered in the ocean’s interior on time scales of months to millennia. In particular, EXPORTS will advance satellite diagnostic and numerical prognostic models by comparing relationships among the ecological, biogeochemical and physical oceanographic processes that control carbon cycling across a range of ecosystem and carbon cycling states. EXPORTS will achieve this through a combination of ship and robotic field sampling, satellite remote sensing and numerical modeling. Through a coordinated, process-oriented approach, EXPORTS will foster new insights on ocean carbon cycling that maximizes its societal relevance through the achievement of U.S. and International research agency goals and will be a key step towards our understanding of the Earth as an integrated system.

Goal
Hypothesis
Why EXPORTS?
Why Now?
The EXPORTS Science Questions:
  1. How do upper ocean ecosystem characteristics determine the vertical transfer of organic matter from the well-lit surface ocean?
  2. What controls the efficiency of vertical transfer of organic matter below the well-lit surface ocean?
  3. How can the knowledge gained be used to reduce uncertainties in contemporary & future estimates of the export and fates of NPP?

NASA’s satellite ocean-color data record has revolutionized our understanding of global marine systems by providing synoptic and repeated global observations of phytoplankton stocks and rates of primary production. EXPORTS is designed to advance the utility of NASA ocean color assets to predict how changes in ocean primary production will impact the global carbon cycle. EXPORTS will create a predictive understanding of both the export of organic carbon from the well-lit, upper ocean (or euphotic zone) and its fate in the underlying “twilight zone” (depths of 500 m or more) where a variable fraction of that exported organic carbon is respired back to CO2. Ultimately, it is this deep organic carbon transport and its sequestration that defines the impact of ocean biota on atmospheric CO2 levels and hence climate.

EXPORTS will generate a new, detailed understanding of ocean carbon transport processes and pathways linking phytoplankton primary production within the euphotic zone to the export and fate of produced organic matter in the underlying twilight zone using a combination of field campaigns, remote sensing and numerical modeling. NASA’s upcoming advanced ocean measurement mission, PACE, will be aimed at quantifying carbon cycle processes far beyond today’s ocean color retrievals of phytoplankton pigment concentrations, optical properties and primary production rates. The overarching objective for EXPORTS is to ensure the success of these future satellite mission goals by establishing mechanistic relationships between remotely sensed signals and carbon cycle processes. Through a process-oriented approach, EXPORTS will foster new insights on ocean carbon cycling that will maximize its societal relevance and be a key component in the U.S. investment to understand Earth as an integrated system.

Timeline:
2018

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