Award: OCE-1536644

This grant supported the Oceanic Flux Program (OFP) time-series of the ocean particle flux (sedimentation) in the deep Sargasso Sea. The OFP is the longest running deep ocean time-series of its kind and has been continuously supported by the NSF since 1978. The OFP reached a milestone in April 2018, celebrating its 40th year of continuous operation. The ocean's particle flux is the primary food source for most life living beneath the surface sunlit zone of photosynthesis, and controls the ocean cycling of nutrients, elements and, in part, the uptake of carbon dioxide from the atmosphere. An overarching OFP objective is to better understand the fundamental processes that regulate generation of the particle flux and its recycling within the ocean interior. In addition to core OFP mooring and sample processing activities, the grant supported detailed analyses of the elemental and organic composition of particle flux. These activities have provided fundamental new insights on particle flux generation and how ecosystems operating within the ocean interior modulate and modify the flux of particulate material from the overlying surface ocean. Additionally, results show that the mid North Atlantic gyre is a net sink for continental materials that are transported into the region by deep ocean currents, providing new information about the many connections beween the land and ocean environments. Results from detailed studies of the organic composition of suspended as well as sinking particles, together with upper ocean physical and biological data collected by the OFP and Bermuda Atlantic Time Series, provided the first direct evidence that hurricanes- by increasing nutrient upwelling to induce transient phytoplankton bloom/flux events- may increase the delivery of fresh, organic material to the deep ocean, a finding that has far-ranging implications for deep ecosystem functioning and elemental cycling. In addition to grant funded research activities, the OFP contributed sample material and cruise opportunities to collaborating scientists in support of independently funded research and to graduate students in support of PhD and MS thesis research. The grant also funded undergraduate REUs and university interns who conducted summer research projects with the OFP. The OFP grants have also long provided meaningful employment to talented high school students who work as part-time lab assistants, providing them training in science skills that are essential for college success. Finally, OFP personnel were engaged in various outreach activities during the grant period, including science programs for local schools, science fairs, ship tours, etc. and the PI presented several well-attended public lectures. Last Modified: 01/02/2020 Submitted by: Maureen Conte