Kneel on the ice of Lake Merrow in January and you can read the winter beneath you. The bubbles stack in white discs, one above another, each layer frozen in place a few days after the last. They are methane, released by the mud at the bottom of the lake as dead reeds and leaves rot. For eleven winters, a…

Three years ago, volunteers laid six hundred mesh bags of oyster shell along the eastern bank of the Merrow estuary, where the old concrete wall had cracked and the marsh behind it was washing away. The shells came from the restaurants on the waterfront, which used to throw them away. Baby oysters settled on them within a season. Now the…