Science at the beach: Coastal ecologist offers sandy insight at HCT guided nature program

For many of us, a day at the beach might involve a swim, a snooze or a spirited session of sandcastle construction. But when you go to the beach with field guide author and science educator Gil Newton, you quickly learn that there’s a whole lot going on in the natural world where land meets ocean.

Newton’s Harwich Conservation Trust program, “Sponges, Seaweeds, Shells & More: Exploring the Intertidal Zone,” drew a curious crew to Red River Beach on a recent morning. We were all delighted to be part of an outdoor classroom, with salt in the air and Nantucket Sound glistening in the background.

“I’m going to show you my favorite place, which is Red River Beach, because of the diversity of habitats and ecosystems that we see,” he said. “What we’re looking at is a barrier beach ecosystem. There are about 200 of them in the state of Massachusetts. And it’s an intersection of many important habitats.”

We began our voyage of scientific discovery on the salt marsh side of the beach parking lot. “A salt marsh is a very healthy ecosystem,” said Newton, a coastal ecology professor at Cape Cod Community College. “And it protects these homes we see behind it from erosion as well as supporting a large number of animals.”

Crabs and roses

Newton deftly scooped up one of those animals, a fiddler crab. We learned that the crabs are filter feeders, noshing on tiny food particles in the mud. And below the little holes they pop in and out of are a series of tunnels that they use to get around.

But even this stealthy approach doesn’t stop other animals from having fiddler crabs for supper. “They are a major source of the food web in salt marshes,” said Newton.

We also delved into the rosa rugosa conundrum. Between the salt marsh and the parking lot, a robust crop of the flowering shrub was doing a good job of anchoring a dune. But Newton told us that the state of Massachusetts considered the non-native plant to be potentially invasive.

“I’m not sure I totally agree with that,” said Newton. “It can be a very effective erosion control plant. It puts out these nice rose hips, which are a fruit for a lot of birds and animals. But there’s no doubt that it can grow very, very thickly, like you see here.”

This rosy issue is a perfect example of how a guided walk can provide intriguing food for thought. On one hand rosa rugosa gives us lovely blooms, dune stabilization and a tasty jelly with a good jolt of vitamin C. On the other hand, it spreads quickly and can displace and outcompete native dune and beach plants.

How old is that quahog?

All along the walk, Newton had the splendid knack of pointing something out or picking something up and introducing fascinating details that might elude the everyday beachgoer.

We found out how to tell the age of a quahog: run your finger along the shell and count the deep grooves. And these commercially valuable bivalves live longer than you might think. “Quahogs can live to be 20 to 25 years old,” said Newton. “Some deep-sea quahogs can live up to 200 years, because of the colder water.”

Next up was an exciting encounter with what some have termed a “living fossil.” Horseshoe crabs “have been on the earth for 450 million years,” said Newton. “They predate the dinosaurs by hundreds of millions of years and have survived climate changes, asteroids, all those things.”

One other thing seemed eternal: a fascinating nature walk with a knowledgeable guide is one of the most exhilarating ways to spend a morning on Cape Cod.

—Harwich Conservation Trust guided nature programs feature expert naturalists in beautiful settings. See our Walks & Events page for upcoming programs and registration info.

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