Reflections on 20 Years of GNATS


Charlie Yentsch, a founder of Bigelow Laboratory, often referred to “our ocean garden.” To be good stewards of the Gulf of Maine, we must regularly observe it and learn what makes our ocean garden grow during this new era of climate change. 

The germ of the Gulf of Maine North Atlantic Time Series (GNATS) was planted in the 1970s, when I worked for Bigelow Laboratory while in high school. I watched Charlie ride a ferry across the Gulf of Maine, inexpensively collecting validation data for the first ocean color satellite. 

This September, GNATS celebrated its 20th anniversary and surpassed 200 trips across the Gulf, providing a great moment to look back at where we’ve come from and where GNATS is headed. 

In 1997, I wrote a proposal to build a portable laboratory we could carry aboard a flatbed truck onto a ferry. The port captain loved that we’d turn his ship into a sophisticated research platform to validate satellites and study the Gulf. With the company’s help and NASA’s support, GNATS was born.

Since then, we’ve crossed the Gulf about 10 times per year. As we cross from Portland, we set up equipment and get power and water flowing to our laboratory. In Yarmouth, we wake up at 4:30 a.m. to prepare for the intense trip back. Ferries today travel faster than when GNATS began, and the team must operate like clockwork as we race back toward Portland.

It takes dedication and hard work to complete over 200 such trips back and forth across the Gulf of Maine. I’ve been fortunate to work alongside a dedicated crew throughout. Bruce Bowler and Dave Drapeau have worked with me since the project began, and countless technicians, postdocs, and students provided invaluable assistance over the years. Together, we’ve created a long-term dataset that provides an unparalleled look at the Gulf of Maine and how it is changing.

Around 2006, we began seeing subtle changes among the phytoplankton that form the foundation of the food web. The Northeast experienced some extraordinarily dry years in the late 1990s and early 2000s, followed by some record flood years. These events resonated through the fragile coastal ecosystem, and they showed in starkest terms how complex and intertwined the Gulf of Maine is with its surrounding watershed.

Recently, we started giving talks during the trip to Yarmouth. Though most passengers have never thought about the bottom of the marine food web, they are interested in stewardship of the Gulf of Maine and have an insatiable appetite for information. Nothing is as powerful as looking out the ferry window, noticing the water color, and contemplating that microorganisms stretch from horizon to horizon — so many that they can be seen from space.

As we move into the future, GNATS gives us the power to detect climate change with extraordinary accuracy and precision. I often posit that the power of a time series increases exponentially with the time it is maintained.

Over the last 20 years, GNATS has made it crystal clear that climate change is happening faster than ever predicted. Creating a time series that allows us to understand, predict, and prepare for these interconnected changes has been one of the most fulfilling things I’ve ever done — in essence, caring for the ocean garden within the Gulf of Maine.