Project: OCE-PRF: Cliff Hangers: Investigating Effects of a Submarine Canyon on the Distribution and Behavior of Midwater Animals and their Predators

NSF Award Abstract:
This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

The deep open ocean waters house the largest animal communities on our planet. These communities remain largely understudied but are known to provide critical services including carbon export from the surface ocean into the deep-sea and feeding economically and socially important fish stocks and marine mammals. These midwater animals are the key link between the base of the marine food web and important predators, which rely on finding and exploiting dense prey aggregations. However, relatively little information currently exists about the oceanic mechanisms or the ecological drivers that shape the distribution patterns of these important prey. Submarine canyons are common features along coastlines that link the deep open ocean with the nearshore ecosystem. They are hotspots of both biological and human activity. This project will examine the role of a submarine canyon on the distribution, density, and diversity of the midwater community and subsequent impacts on the abundance and habitat-use of top predators with a combination of acoustic, visual, and biologging techniques. This project will support the training of a post-doctoral researcher and support the recruitment and retention of women in STEM by providing resources to further the development of a continuous support network for local female-identifying STEM community college students transferring to the local public 4-year university. The results of this project will also be shared with the public through a bilingual digital exhibit at the Seymour Marine Discovery Center in Santa Cruz, CA.

The deep midwater (200-5000 m depths) is the largest habitat on our planet and represents over 90% of the entire biosphere, yet it is still one of the least understood and most mysterious ecosystems. Deep pelagic communities are now known to provide critical ecosystem services including carbon export from the surface ocean with sequestration in the deep-sea and provisioning predators like economically and socially important fish stocks and marine mammals. However, relatively little information currently exists about the oceanic mechanisms or the ecological drivers that shape the distribution patterns of these important mid-trophic level animals. Submarine canyons are common abrupt bathymetric features that bring together normally separated deep oceanic and shallow nearshore communities and have profound influences on coastal ocean dynamics and ecosystems. Canyons are often hotspots of both primary production and predator activity. This project will investigate the role of submarine canyon bathymetry on the distribution, density, diversity, and composition of the midwater community linking these two trophic levels and the subsequent impacts on the abundance and habitat-use of top predators. This project will compare communities at a canyon wall site and at a midwater time series site, identify the oceanographic drivers and mechanisms driving variability in the near-wall community, and determine the relationships between predator distribution and canyon bathymetry through a combination of acoustic, visual, and biologging techniques. Current knowledge of the linkages between deep midwater and shelf communities remains limited, but increasing anthropogenic stressors like fishing, pollution, and climate change demand ecosystem-based solutions fundamentally based on understanding these interconnections. By investigating the mechanisms and drivers of the relationships between bathymetry, oceanographic conditions, deep water pelagic prey, and their predators, this project will help to address this knowledge gap, and the results will have important implications for the management and conservation of groundfishes and marine mammals.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.