Researchers to Explore Relationship Between Volcanoes, Ocean Ecosystems

A team of interdisciplinary researchers at Bigelow Laboratory and Colby College will explore how volcanic ash supports marine ecosystems with a new $600,000, four-year grant from the North Pacific Research Board.

The northeastern Pacific Ocean is a productive ecosystem built on a foundation of phytoplankton. These microscopic algae form the base of the ocean food web, and their populations are largely controlled by the amount of available nutrients, particularly iron. Many of these nutrients come from land, such as dust and volcanic ash, and studies have shown large phytoplankton blooms happen after volcanic eruptions. However, scientists do not know how volcanic ash compares to other nutrient sources over long periods of time.

Led by Senior Research Scientist Catherine Mitchell and Colby College Assistant Professor Bess Koffman, the project will assess the impacts of volcanic ash using satellites, ship-based experiments, and geological and chemical analyses.

“We’re asking a simple question: how does ash influence phytoplankton blooms?” Mitchell said. “But getting the answer requires a complex, interdisciplinary process. We all have quite different backgrounds and expertise, and I’m excited that we're bringing them together.”

The team also includes Senior Research Scientist Benjamin Twining and Karen Stamieszkin, an adjunct scientist at Bigelow Laboratory.

The team will focus on the Aleutian Islands in Alaska, one of the most volcanically active regions on the planet. Nutrients from ash there feed phytoplankton that support vital fish populations for native Alaskan communities and the region’s multi-billion-dollar fishing industry.

“Phytoplankton support the entire ocean ecosystem,” Mitchell said. “So by learning about them we can learn about fish and other critical species that humans and the environment rely on.”

Satellites provide one of the best ways to study the distribution of phytoplankton and ash, but it is challenging to distinguish the two. Mitchell started her career studying relationships between sediments and phytoplankton, and she will lead the development of a computer-based method for accurately distinguishing phytoplankton from dust and ash in satellite imagery.

Because the researchers want to understand the long-term relationship between ash and phytoplankton, they will also study ash released from previous eruptions. Koffman’s research has shown that the properties of ash change through time, gradually making its nutrient content more accessible to phytoplankton. To explore this, researchers will study aged volcanic ash that has been picked up by wind or water after months to decades of sitting where it fell.

“As climate change continues to impact this region, the relative importance of different nutrient sources may change,” Koffman said. “This is one reason why we are really excited to have the chance to study these processes.”

The team will also participate in two research cruises in the Gulf of Alaska to conduct at-sea experiments. Researchers will collect phytoplankton from the ocean and grow them, adding different ashes to see how they respond.

The team has also partnered with the Aleut Community of St. Paul Island in Alaska. The scientists will work with community members to document traditional knowledge, which will be incorporated into the research to provide insight into the natural history of the region. In parallel, the researchers will share their science with Aleut youth through outreach activities over the course of the four-year project.

“We're approaching the Aleut collaboration with an open mind looking for how we can mesh their knowledge with our Western science approach,” Mitchell said. “We also want to build a long-term relationship where we can return that goodwill and, hopefully, provide the community with valuable experiences.”

Photo credit: Ben David Jacob