Researchers powering marine science with ambient energy

Shafer has been awarded a $634,000 grant from the National Science Foundation to develop energy-harvesting technologies for monitoring marine mammals.

Scientists place tags with GPS sensors on animals so their activities and environments can be observed and studied.

Current research is limited by the sensors' short battery lifespans or because data is stored on a memory chip and needs to be retrieved from the animal. Some systems offload data to satellites but the process requires a lot of energy.

Shafer's grant will explore energy harvesting from the environment, using elephant seals for the initial experiments.

"We are examining a variety of transduction methods to help supplement the energy budgets of these tags when they are deployed," Shafer said. One of the methods is solar radiation, which uses the sun to power tags at various depths. The other method would harness energy created by the elephant seals as they swim and dive in the ocean.

Elephant seals can weigh up to 8,800 pounds, nearly as heavy as a five-ton monster truck. The mammals regularly travel 2,620 miles between the central California coast and Alaska's Aleutian Islands.

Methods for these prototypes each have potential, and drawbacks. "One solution is not going to work for all animals so we are interested in finding one or two technologies that can work over a broad spectrum of species and provide the most usability," Shafer said.

Paul Flikkema, professor of electrical engineering and computer science at NAU, will join Shafer on the NSF-funded wildlife monitoring and employ graduate and undergraduate students to work on the research. The group will also collaborate with the University of California, Santa Cruz, which has a long history of marine mammal research.