https://phys.org/news/2018-06-plunge-ocean-twilight-zone-explore.html

The research vessels, the R/V Revelle and R/V Sally Ride, operated by the Scripps Institution of Oceanography, University of California San Diego, will sail west 200 miles into the open ocean. From these seaborne laboratories, researchers will explore the plankton, as well as the chemical and physical properties of the ocean from the surface to half a mile below into the twilight zone, a region with little or no sunlight where the carbon from the plankton can be sequestered, or kept out of the atmosphere, for periods ranging from decades to thousands of years.

"By employing two ships we'll be able to observe complex oceanographic processes that vary both in space and time that we wouldn't be able to capture with a single ship," said Paula Bontempi, program manager for Ocean Biology and Biogeochemistry at NASA Headquarters.