URI_Research_Magazine_Momentum_Fall_2018_Melissa-McCarthy

Since the beginning of her career, University of Rhode Island (URI) Professor Bethany Jenkins has worked to understand how photosynthetic organisms that live in the ocean both cope with low nutrients and respond to pulses of nutrient input — especially in ocean ecosystems with low iron levels. In particular, she studies diatoms, a type of plankton with cell walls made of silica or glass. Diatoms are the floating, single-celled plants of the ocean. These organisms, through photosynthesis, use the energy from sunlight and carbon dioxide to create food. They act as the base of a food web that sustains other animals in the ocean. When fueled by iron, these microorganisms increase their activity, turning carbon dioxide into organic carbon and generating oxygen. If diatoms run out of iron or other required nutrients, they stop growing and sink below the ocean surface, if not eaten by a predator first. “When they sink, that’s a good thing,” explains Jenkins. “Because the carbon gets sequestered in the ocean floor, they’re fueling the food web, which is also good. I’m trying to understand the relation of iron and silica to diatom growth and sinking.” During the summer 2018 EXPORTS campaign in the Subarctic Pacific Ocean, Jenkins studied these ocean processes and resulting changes in ocean chemistry. She and URI colleague Susanne Menden-Deuer (article page 14) also served on NASA’s scientific definition committee, which established the framework for the campaign and resulted in a cross-section of projects that pools expertise in the movement of organisms and nutrients from the surface into the ocean deep and marine food web.