Researchers incorporated phytoplankton and their feces into a unique ecosystem model designed to look at the ocean's carbon export.
The research team used satellite observations that determined net primary production (NPP), which is "the net production of organic matter from aqueous carbon dioxide (CO2) by phytoplankton," a University of California Santa Barbara news release reported.
They focused on the ocean's "biological pump" that exports organic carbon from the upper ocean through "sinking particulate matter."
"What we've done here is create the first step toward monitoring the strength and efficiency of the biological pump using satellite observations," oceanographer David Siegel, director of the Earth Research Institute at UC Santa Barbara who is also a professor of marine science in UCSB's Department of Geography. "The approach is unique in that previous ways have been empirical without considering the dynamics of the ocean food web."
Carbon exists in the atmosphere and is stored in the Earth's soil and crust. Researchers believed the ocean is a key player in the global carbon cycle.
"Quantifying this carbon flux is critical for predicting the atmosphere's response to changing climates," Siegel said. "By analyzing the scattering signals that we got from satellite measurements of the ocean's color, we were able to develop techniques to calculate how much of the biomass occurs in very large or very small particles."
The results predict a mean global carbon flux (movement of carbon) of six petagrams per year; this is about equivalent to annual global fossil fuel emissions.
"It matters how big and small the plankton are, and it matters what the energy flows are in the food web," Siegel said. "This is so simple. It's really who eats whom but also having an idea of the biomasses and productivity of each. So we worked out these advanced ways of determining NPP, phytoplankton biomass and the size structure to formulate mass budgets, all derived from satellite data."
"Understanding the biological pump is critical," Siegel said. "We need to understand where carbon goes, how much of it goes into the organic matter, how that affects the air-sea exchanges of CO2 and what happens to fossil fuel we have emitted from our tailpipes."
