Jacquelyn Veatch (Coastal PO Faculty Search Candidate) - SMSP Spring Seminar Series 2026

Jacquelyn Veatch

Abstract: The patchy distribution of prey in marine environments strongly shapes upper trophic level foraging behavior and predator distributions, yet the physical mechanisms that organize these prey fields across multiple trophic levels remain poorly understood. Fine-scale ocean circulation can disperse or concentrate low-motility plankton into dynamic patches, and passive particle simulations reproduce similar spatial patterns. However, whether such transport structures also influence motile zooplankton, such as krill, and their predators remains unclear as well as the relative contributions of transport and local growth to plankton patchiness. To test whether finescale surface transport structures organize an entire coastal food web, we combined in situ optical observations of phytoplankton patches, high-resolution acoustics detecting Antarctic krill (Euphausia superba) swarms, and GPS tracking of Adélie (Pygoscelis adeliae) and gentoo (Pygoscelis papua) penguins in Palmer Deep Canyon, Antarctica. Hourly surface currents measured by High Frequency radars were used to estimate attracting Lagrangian Coherent Structures (LCS), which identify regions of flow convergence. Phytoplankton patches, krill swarms, and foraging penguins were all preferentially located along attracting LCS, indicating that fine-scale circulation structures biological production and predator foraging across trophic levels. Elevated productivity in Palmer Deep has traditionally been attributed to canyonmediated upwelling of nutrient-rich deep water. To evaluate the relative roles of nutrient-driven growth and physical concentration, we analyzed the surface chlorophyll budget using radar velocities and satellite chlorophyll maps. Biological accumulation and horizontal advection were comparable in magnitude overall, though advection dominated on the canyon’s western flank. Together, these results show that nutrient supply and fine-scale transport act in concert to focus prey fields and sustain this coastal ecosystem.