Award: OCE-2048481

This project investigated microbes that process methane, animals that eat those microbes or partner with them, and other species that benefit from methane-rich habitats. Our project took a broad approach, integrating chemistry, microbial biology, symbiosis, and food-web studies to investigate how methane shapes deep-sea ecosystems. Microbes and animals along the ocean’s continental margins use methane, a powerful greenhouse gas, in sometimes surprising ways. We conducted seafloor studies on two multi-institution expeditions to methane seeps off of the Southern California; Del Mar and Santa Monica (aboard the RV Atlantis, with HOV Alvin; July 2023) and very deep-sea sites off of the Aleutian Island chain, Alaska (aboard the RV Atlantis, with HOV Alvin; May-June 2024). One of the primary objectives of this research was to identify the diversity of animal-microbe interactions involved in the consumption of methane, conversion to biomass, and transfer through the food web. Symbiotic partnerships, in particular, have shaped life on Earth. In the deep ocean, many animals depend on bacteria that can tap into unusual energy sources, like sulfide or methane, that animals cannot use on their own. Bacteria allow animals to take advantage of these varying chemical resources, an adaptability that explains why symbioses between invertebrates and microbes are so successful and diverse in the deep ocean. Our discoveries from this NSF-funded research program revealed widespread, overlooked partnerships between animals and methane-eating bacteria in groups such as sea spiders, sponges, and hydroids. Because methane seeps are isolated, complex habitats that support high productivity and unique species, understanding them is important for our general understanding of where methane comes from, how it moves through food webs, and how living organisms consume it, thus allowing for a prediction of future climate trends. Methane seeps on these margins store and transform large amounts of carbon, influencing climate feedback. Deep, high-latitude sites are especially vulnerable to warming and disturbance, yet they remain poorly studied. By uncovering how microbes, methane, and animals interact, we can better predict carbon storage, ecosystem productivity, and biodiversity in a changing ocean. Additionally, our broader impact goals included engaging with the Alaska Native Science and Engineering Program (ANSEP) to help promote college readiness and successful completion of STEM degrees. We engaged students in learning about deep-sea science, the interesting ecosystems we study, and the variety of career pathways available to students who pursue study in marine science related fields.

Last Modified: 12/01/2025
Modified by: Shana K Goffredi