Leaving Roundstone Bog and heading east, along local road L1205, hollows left by peat removal had refilled with bog water. I knelt down and picked up a handful of bright-green sphagnum moss from the water"s edge and squeezed it. Water flowed out and ran down my wrist. Sphagnum moss can hold more than 12 times its own weight in water and acidifies it. It"s also an ecosystem engineer, as it creates peat bog, and here, it was regrowing after small-scale peat cutting a few months earlier.