Award: OCE-2049307

This project investigated how climate-driven changes in surface-ocean food webs affect the transfer of organic matter from the sunlit ocean to deep-sea ecosystems. This transfer, often called export production or the biological pump, is important because it helps support deep-sea life and contributes to long-term carbon storage in the ocean. The project focused on the Gulf of Maine, a rapidly warming ocean region where changes in water temperature, ocean currents, plankton communities, and food webs are already affecting ecosystem structure and function, including important fisheries, endangered whales, and other ecosystem services.

The project combined two high resolution, long-term natural archives with cutting edge molecular isotope and modeling approaches to reconstruct changes in ocean food webs over many decades. Plankton archives from NOAA’s Ecosystem Monitoring Program (EcoMon + MARMAP, 1977-2025), the Continuous Plankton Recorder (CPR, 1961-2023), and the Gulf of Maine North Atlantic Time Series (GNATS, 1998-2020) record food web changes in organisms living near the surface. Deep-sea corals act like “living sediment traps,” recording the surface ocean-produced organic material that reaches the seafloor over time in continuous growth rings of their protein skeletons. The project used compound-specific isotope analysis of amino acids of plankton and deep-sea coral tissues to reconstruct changes in phytoplankton sources, zooplankton food webs, microbial processing, and the composition of material exported to depth.

The project produced a major study of Gulf of Maine copepod population dynamics showing that warming has overtaken stratification as a key driver of changing zooplankton population phases. This result provides important context for understanding how climate change alters the animals that mediate energy transfer through marine food webs. Additional products included new isotope tools for identifying phytoplankton sources, regional isotope maps for the Northwest Atlantic shelf, and related applications to fisheries and movement ecology.

One major scientific outcome was the discovery that increased microbial recycling in the surface ocean does not necessarily weaken connections to the deep sea. Classical food-web theory often predicts that when more organic matter is processed by microbes near the surface the coupling of that microbially reprocessed production to the deep-sea is weakened. In contrast, this project found that microbial processing and strong pelagic-benthic coupling can occur together when large-bodied zooplankton, especially the copepod Calanus finmarchicus, package surface production into sinking fecal pellets. These fecal pellets can move microbially transformed production from the surface ocean to deep-sea coral ecosystems. This finding refines how scientists understand the biological pump by emphasizing not only whether microbial processing occurs, but also whether large zooplankton remain in the food web to package and transport material downward. This work shows that not only are the processes that link large zooplankton to deep-sea corals through microbial loop food web dynamics important, but they are increasing through time as oceans warm in the region.

The award supported extensive training and professional development. It formed the basis of Dr. Catrina Nowakowski’s doctoral dissertation and supported student-led publications and presentations. It provided training for postdoctoral researchers, research staff, graduate students, undergraduates, and engineering students in isotope geochemistry, deep-sea coral processing, plankton ecology, oceanographic fieldwork, remotely operated vehicle operations, quantitative analysis, and science communication. Project material was incorporated into undergraduate and graduate courses in oceanography, ecology, isotope geochemistry, engineering, multimedia reporting, and newsroom production.

The project also generated substantial broader impacts through public communication. Scientists, artists, filmmakers, journalism students, and public media collaborators translated the project’s Gulf of Maine food-web data into sculpture installations and a short documentary film, The Coral & The Copepod. The film follows scientists aboard the R/V Endeavor as they collect plankton and use a remotely operated vehicle to sample deep-sea corals, making ocean exploration and climate-change research accessible to broad audiences. A companion study evaluated how public audiences responded to scientific figures and sculpture-based visualizations. The assessment showed that a more literal organism-based sculpture produced the strongest gains in comprehension, engagement, and ease of understanding, while scientific figures retained the highest perceived credibility. Together, these products show how rigorous ocean science can be translated into public-facing visual, material, and narrative forms that preserve scientific credibility while expanding access, engagement, and climate literacy.

 

Last Modified: 06/29/2026
Modified by: Kelton McMahon