This project will advance understanding about the contribution of host and gut-associated microorganisms to the digestion of wax esters, a major prey lipid, in the Arctic-dwelling bowhead whale. Digestion and storage of lipids, the most energy containing of all food molecules, are essential to the physiology (i.e., heat balance, growth, and reproduction) of mammals. Despite the importance of this process, there is little knowledge about how marine animals digest wax esters, an abundant lipid in the marine food web. The bowhead whale is critically dependent on wax ester digestion and fat accumulation, but nonetheless thrives in a freezing environment and lives longer than any other mammal on Earth. Thus, this work will extend knowledge about bowhead whale, microbiome and digestive processes beyond what is currently known in other mammals, including humans. This research will provide scientists with a framework to investigate how changes in prey, due to changing climate, may impact whale digestion and fat gain. The team will communicate project findings broadly through publicly accessible narratives shared through press releases and an on-line magazine. The Native Alaskan hunters and their families are an integral part of this project and also possess extensive traditional and recorded knowledge about the bowhead whale. To strengthen partnerships between scientists, managers, and stakeholder communities, the team will hold conversations about this project with the Whaling Captain’s Association and their families in Utqiagvik, Alaska, the northernmost U.S. city that hosts Native subsistence bowhead whale hunts, and has a population of approximately 60% Iñupiat Eskimos. This project will also train undergraduates in emerging host-microbiome research methods.
This project brings together expertise in lipidomics, microbial ecology, whale physiology and genomics to address how the host, gastrointestinal tract microorganisms, and their interactions play a role in wax ester lipid digestion, a fundamental metabolic process that is understudied in marine animals. The investigators plan to conduct experiments and analyses centered on two aims: 1) to examine the enzymatic potential for host-based digestion of wax esters and 2) to determine if gut-associated microorganisms digest wax esters. These analyses will result in a conceptual model for wax ester digestion in whales, based on host and microbial interactions and processes. Specifically, the team plans to conduct experiments with digestive fluids and intestinal contents collected from up to five different sites within the gastrointestinal tract of subsistence-harvested bowhead whales to examine the hydrolysis of isotope-labeled wax esters, and the contributions of the host and the microbial community to digestion. This project has the potential to advance and produce knowledge on microbial hydrolysis of wax esters, a lipid of considerable importance and abundance in the ocean, for which no microbial degradation sources are yet known. Results may be applied to predicting how climate change may affect bowhead whale feeding ecology. The researchers will engage in public education outreach activities with Native Alaskans to exchange knowledge about bowhead whales and by presenting results to the Alaska Eskimo Whaling Commission.
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.
