Scientists struggle to save seagrass from coastal pollution

Durham, N.H. — Peering over the side of his skiff anchored in the middle of New Hampshire’s Great Bay, Fred Short liked what he saw.

Just below the surface, the 69-year-old marine ecologist noticed beds of bright green seagrass swaying in the waistdeep water. It was the latest sign that these plants with ribbon-like strands, which had declined up to 80 percent since the 1990s, were starting to bounce back with improved water quality. Seven rivers carry pollution from 52 communities in New Hampshire and Maine into the 1,020-squaremile watershed for the bay.

“It actually looks better than it did last year at this time and better than has in many years,” said Short, a noted seagrass expert who coordinates the monitoring of 135 sites around the world from his University of New Hampshire lab.

“You see here,” he said, glancing into the water. “It’s nearly 100 percent cover. You look to the bottom. You can’t see the mud. You just see eelgrass. That is as dense as it gets. That’s a really good sign.”

Seagrass beds in New Hampshire and along shorelines around the world are important because they have been found to provide food and shelter for fish, shellfish and sea turtles. They also blunt the impacts of ocean acidification, reduce coastal erosion and keep the water clean by filtering out excessive nutrients.

Their comeback in the Great Bay gives hope for recovery elsewhere.

The more than 70 species of seagrasses are among the most poorly protected but widespread coastal habitats — more than 116,000 square miles have been mapped, though there could be 10 times that. They are found along coastlines around the world except Antarctica’s.