Defying Fall Weather to Explore Ocean Ecosystems

Defying Fall Weather to Explore Ocean Ecosystems

Each spring, the waters of the North Atlantic Ocean host a huge natural bloom of phytoplankton—microscopic, plant-like organisms that are important for carbon cycling and also could influence clouds and climate. Blooms occur in the North Atlantic in fall as well, but the typical weather can make them difficult to observe.

“A lot of what we don’t know about ocean ecology has to do with the difficulty of sampling the ocean,” said Norman Kuring, an ocean scientist at NASA’s Goddard Space Flight Center, “whether it be from a storm-tossed ship or from a cloud-obstructed satellite.”

On September 23, 2015, the weather was adequate for the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP to acquire this view of a bloom in the North Atlantic. The image was composed with data from the red, green, and blue bands from VIIRS, in addition to chlorophyll data. A series of processing steps were then applied to highlight color differences and bring out the bloom’s more subtle features. (The process also accentuates striping artifacts from the detectors that can be seen throughout the image.)

“The image does a beautiful job of showing the close link between ocean physics and biology,” said Michael Behrenfeld, a phytoplankton ecologist at Oregon State University. “The features that jump out so clearly represent the influence of ocean eddies and physical stirring on the concentration of phytoplankton pigments and, possibly, colored dissolved organic matter.”

Six weeks after this image was acquired, researchers were in this area with NASA’s North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). The study aims to make ship- and aircraft-based measurements that, when combined with satellite and ocean sensor data, will help clarify the annual cycles of ocean plankton and their relationship with atmospheric aerosols. The first field campaign of the five-year study began November 6, 2015, and concluded December 1.

Researchers on the ship-based part of the study ran into some wicked November weather. Christien Laber, a doctoral student at Rutgers University, captured this photograph during a storm on November 19, when the research vessel Atlantis was off of the Newfoundland Shelf. Some research had to be put on hold for the day, though some continued through the storm.

“We have a ton of analyses to do to fully determine all the cool things that were going on out there,” said Behrenfeld, the principal investigator for NAAMES. “What I do know is that the ship data transected through a range of phytoplankton concentrations, and that these features were associated with ocean physical features.” Moreover, the plankton observed were diverse and in good health, “as if they are ready to bloom given any chance.”

As expected, the number of plankton in the water in November was very low. Behrenfeld explained: “It is likely that these low concentrations have an impact on predator-prey relationships between phytoplankton and the zooplankton that eat them.”

The effect of plankton, however, can sometimes reach beyond the sea and into the atmosphere. Rich Moore, a researcher at NASA’s Langley Research Center and deputy project scientist for NAAMES, explained that biological organisms release organic molecules into their surrounding seawater. This seawater, organic particles and all, can then be lofted into the air as sea spray.

“These biologically-driven aerosol influences have been detected as far away as coastal monitoring stations in Ireland,” Moore said. “However, we have much less information about what is going on out in middle of the ocean. NAAMES will attempt to fill this important scientific gap by studying the link between the bloom, any changes in the overlying atmospheric aerosols, and how these changes may then go on to affect clouds and regional climate.”

The next NAAMES campaign will begin in May 2016. “This is going to be the climax of the bloom,” Moore said “and will serve as an exciting foil to the minimum that we just characterized in November.”

NASA image by Norman Kuring, using VIIRS data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Photograph by Christien Laber, Rutgers University. Caption by Kathryn Hansen.

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