Photo by Charlie Russell

NORFOLK, Va. (AP) – Humans can take credit for the comeback of grasses growing at the bottom of the Chesapeake Bay.

That’s the conclusion of a study released recently in the Proceedings of the National Academy of Sciences.

The Virginian-Pilot reported Friday that the study found the bay to be “one of the few places on Earth” where long-term improvements can be linked to humans.

The bay experienced an “unprecedented decline” in grasses in the 1970s. That was partly due to a fierce tropical storm but also waste from the area’s increasing population. Runoff from agriculture was another factor.

Efforts to restore the bay have included a “pollution diet” that restricts what goes in to the Chesapeake. Since the 1980s, grasses have recovered by threefold. They covered about 60,000 acres in 2015.