I spent the last week of September kayaking daily through the Great Marsh in Newburyport. The purpose of the trip was to introduce a new crop of seventh graders to a more intimate look at the largest marsh in the Northeast. The first thing I noticed was the change in color from my last trip just a few short weeks earlier. The brilliant green of the majority of marsh plants was now showing a cloak of brown and gold, late blooming goldenrod was waving bright golden tops, and in the low marsh salicornia, or marsh "pickle'', was turning a blazing red in any bare spots it could colonize. The Gulf of Maine is warming as fast as any body of water in the world, and today it seems at least as warm as the air, which is in the seventies. In the marsh and in the air, the animals are "staging", getting ready to move on South.
The ancient Greek philosopher Heraclitus once said "nothing endures but change". The enduring change around us allows our world to stay much the same. Marsh inhabitants are tuned into its timeless rhythms and have adapted their life cycles to it. Change is most noticeable in the fall, and September brings us the drama that is autumn in the Gulf of Maine. Stimulated by hormones and perhaps the lessening amount of daylight, our migratory birds have been feasting and packing away stores of fat and carbohydrates while awaiting the right signal from the rest of the flock. Some birds are just leaving but others are arriving from Artic Canada, using this marsh as a resting point before moving on. While the brant will stay awhile and maybe winter over, skeins of double-crested cormorants are heading south to be replaced in winter by great cormorants from northern Europe.
I am pleased and encouraged to see, and happy to point out to the students, that the air is filled with migrating monarch butterflies. Many insects migrate along with the birds and these monarchs face an arduous journey of 2,500 miles to their winter grounds in Mexico. They are about a tenth or twentieth of the millions who used to fill the September skies. None of these monarchs have made the journey before. They are the descendants of many generations of those who left last year. As we slowly make our way downriver I pull the kayaks into the low marsh which is dominated by cordgrass, a plant that can excrete salt thus allowing it to be inundated by the tide twice a day. Students are learning that everything in the marsh is interconnected. For now they are content to find glistening salt crystals on the stems above water. Some of the more observant find a rounded snail crawling on the stems below water and soon all of the students have "adopted" their own periwinkle and are humming away, trying to get it to open its operculum and respond to their humming.
Periwinkles are molluscs, a group of animals that have two distinguishing characteristics found nowhere else in the animal kingdom. One, the mantle, is a fold in the body wall that secretes the calcium carbonate that makes up a mollusc shell. The other, the radula, a ribbon like tongue made of chitin (like a lobster shell), is armed with tiny teeth that scrape algae from the rocks and perhaps from cordgrass stems, too. The students will learn about the natural capital services provided by the marsh like serving as a nursery for open ocean fish, providing food for migratory birds, acting as a buffer against storms, and much more. They also provide an effective check on the forces driving climate change by trapping carbon that would otherwise be released into the atmosphere. But as we shall soon see, these wetlands can no longer keep pace with the rising sea. Their growth is slower than the sea level rise and is blocked here by a road and homes, preventing them from gaining any new ground.
Moving downriver, we find bare patches of mud flat and some areas where chunks of marsh with cordgrass have peeled away from the main marsh of Woodbridge Island, allowing a new channel to push through. One of the major contributors to marsh bank destabilization is the overabundance of green crabs. They probe the banks of tidal creeks for clams and mussels, leaving gaping holes behind. We are now paddling through cordgrass that is mostly underwater only an hour or two past low tide and is separated from the island. Weakened by crabs digging in the soil, sections of the marsh have broken away in storms. As water continues to rise, the smaller marsh piece will not be able to capture carbon as well as it did before.
I hope the students have learned some things from their exploration of the Great Marsh and have been touched by the threats of a different kind of change. They will have opportunities to get involved with research and ongoing projects at Plum Island, our kayaking destination. Hopefully some of them will be moved enough to join the ranks of those trying to diminish the impacts on this beautiful place bursting with animal activity and resplendent in its autumn colors.
1. Catherine Schmitt, 2008, A Coastal Companion, Tilbury House, Gardiner Maine
2. Schmitt, 2008
3. Thurston, Harry, 2011, The Atlantic Coast, Greystone Books, Vancouver BC
4. Ramos, Nester, 2019, "At the Edge of a Warming World", Boston Globe, September 29, 2019
5. Ramos, 2019
John Halloran is the Director of Science for GOMI and a member of the GOMI Guide Team. John’s interests focus on the ocean environment where he pursues educational adventure travel, research, and recreation by sail, paddle, and scuba.John is the founder and director of Adventure Learning, Newburyport, MA, which has been involved with educational outreach in area schools and recreational programs for teens and adults since 1980. A long-time educator, John was at the forefront of the experiential education movement in the U.S. for 36 years, he taught natural science in the Newburyport Public Schools.