The scientists used undersea gliders in their Hawaii study to monitor the water from the pump so they have an idea how widely and quickly it disperses, and how much of an impact it can have on surface waters.
"We know a lot about how upwelling works and the physics of the ocean," Letelier said, "but there also are things we don't know, which is why this study is so important. In this open ocean area near Hawaii, for example, phytoplankton blooms occur in the summer when there are almost no nutrients at the surface and the winds generally are calm. What triggers the blooms and where are the nutrients coming from? We need to know.
"These vast, seemingly barren regions comprise more than two-thirds of our oceans and nearly 40 percent of the entire Earth," he added. "It is a large area of exchange between the atmosphere and the ocean and understanding large-scale interactions is critical to understanding climate change."
Some scientists have looked at iron fertilization as a way to trigger biological growth in nutrient-poor areas of the ocean, but "everything responds to iron," Letelier said. "You can't control what grows."
The researchers believe they can control plankton growth by determining which species respond to specific nutrients, and then adjusting the rate of nutrient feeding by the frequency and duration of water pumping.
"These vast regions of the open ocean may be perfect for sequestering carbon," Letelier said, "but before we can begin to seriously consider a large-scale intervention, we must better understand how the biology responds by using perturbations on a small scale.
|Contact: Ricardo Letelier|
Oregon State University