Watch the Live Stream here or here

Abstract:

Dissolved oxygen plays a major role in determining the composition and vertical distribution of mesopelagic prey that are of global ecological importance due to their large biomass. Recent work that documented prey capture events at >800 m suggested that the oxygen minimum zone (OMZ) provides important foraging habitat for northern elephant seals (Mirounga angustirostris) where they can target sluggish mesopelagic prey. In this talk, I will start by detailing some of my PhD work in which I assessed northern elephant seals’ population-level use of OMZs across their two annual foraging trips by combining tracking and diving data from 364 adult female seals with modeled monthly dissolved oxygen data from Copernicus Marine Service. Overall, I found that, at the population level, seals primarily used the OLZ, but I will dive deeper into the diel, regional, and seasonal differences that exist, and which strategy led to greater foraging success. Finally, I will highlight a current project with collaborators that is using newly developed dissolved oxygen loggers (Little Leonardo Ltd.) to obtain in situ oxygen data at the same resolution of the seals’ foraging behavior. These data will better elucidate the indirect effects of dissolved oxygen on their foraging behavior. Through this work, we have determined elephant seals can serve as a sentinel species for monitoring ecosystem-level impacts of OMZ expansion associated with climate change.

Bio:

I am a postdoctoral research fellow working jointly with Dr. Dan Costa (University of California, Santa Cruz) and Dr. Akinori Takahashi (National Institute of Polar Research). I like to call myself a movement ecophysiologist who uses biologgers to study freely diving marine megafauna in their natural context. I am broadly interested in how diving marine megafauna are adapted to and make a living in the marine environment and how they might be affected by anthropogenic disturbances and environmental change. My current research focuses on the diving behavior and foraging ecology of northern elephant seals relative to low-oxygen zones, work that started during my PhD and is continuing for my postdoc. I’ve dabbled in refurbishing and customizing physiological biologgers for some of my dissertation work, and now I’m helping test newly developed dissolved oxygen loggers. I find it exciting to be part of projects that are advancing biologging technology to better answer our research questions. I’ve been fortunate to travel and work with a handful of pinniped species, including crabeater seals in Antarctica, Caspian seals in Kazakhstan, and California sea lions, alongside inspiring collaborators.