The Continuous Plankton Recorder cruises the North Atlantic. Marine Biological Association photo

The world’s oceans remain 95% uncharted, impacting us in ways we may not fully grasp. New research from Boothbay-based Bigelow Laboratory confirms just that. According to Dr. Karen Stamieszkin, the study’s lead author, mysteries don’t start miles below the surface but at the surface itself.

A scanning electron microscope image of Michaelsaria elgans, a type of plankton known to be capable of mixotrophy. Colin Fischer photo

A team of Boothbay researchers examined 60 years of data (1958–2015) on microscopic plankton in the North Atlantic. In a study published in “Frontiers of Marine Science,” the researchers contributed the first basin-level view of how the distribution of mixotrophs varies, detecting an increase in abundance as the Gulf of Maine warms.

The Continuous Plankton Recorder (CPR) survey is run by the Marine Biological Association. Its data proved instrumental for Stamieszkin’s study.

“CPR is a decadal survey designed to sample zooplankton,” Stamieszkin said. “But it also catches large phytoplankton [mixotrophs], which is why it worked well for this study. We found that the data set itself up in a way that compared mixotrophs and photo autotrophs [diatoms].”

For millennia, scientists thought organisms could survive by photosynthesis or consuming prey directly. In the 1900s, they noticed that most marine life do both: mixotrophic organisms shift habits as needed — hence their nickname within the industry, “flexible feeders.”

Stamieszkin found that mixotrophs are most prevalent when it’s warm and nutrients are less abundant — conditions expected to occur more often due to climate change. The study, she said, confirms that the ocean is changing at the molecular level, and since mixotrophs are flexible in how they get food, they possess resilience to global warming.


The results serve as a launchpad for further experiments to examine the impact of mixotrophy on nutrient cycling and predict how marine life will respond to a changing environment. Or so the team hopes.

Trophic index over the CPR study regions (1996-2015). Red indicates more heterotrophs, gray mixotrophs, and blue autotrophs. Marine Biological Association photo

“We didn’t set out to study climate resilience, per se, but our findings pose the question,” Stamieszkin said. “Another thought is: If mixotrophs are more resilient than their counterparts, will they replace those at the base of the food web? The last sentence of the paper says the study is meant to launch further research, and it is. Our work presents new hypotheses to drive science forward.”

Stamieszkin explained that if mixotrophs replaced the base of the planktonic food web, it would impact all oceanic life, including local seafood and the imperiled right whales that Maine is federally required to protect. Plus, microbial life in the ocean produces half the oxygen on Earth. Huge changes in the planktonic community would alter how much oxygen is available for humans to breathe.

Bigelow Laboratory is involved in the Gulf of Maine North Atlantic Time Series, a separate project that has collected data to monitor oceanic changes since 1998.

“Time series that cover a long timeframe and a large space are rare because they are so expensive to fund,” Stamieszkin said. “But they are crucial to understanding our changing ocean and its myriad ecosystems. Marine biotic components, like phytoplankton, are responsible for global nutrient cycling; they directly impact human life.”

Barney Balch, an emeritus Bigelow research scientist, helped get the GNATS program off the ground.

“The power of long-time series of environmental measurements is that one learns about, and establishes, the natural variability of your particular system,” Balch said. “Such work is extremely laborious — making hundreds of cruises along the same transect for decades — but one gains tremendous statistical power to credibly evaluate climate change.”

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