Before it was the Big Apple, New York was the Big Oyster. The city was built at the mouth of the Hudson River, a fertile estuary packed to the gills with marine life. Scientists and historians estimate that trillions of oysters once surrounded Manhattan, and these bivalves filtered out bacteria from the water and served as a food source for the human population. Beneath the waves, these reefs also provided a less obvious benefit: vital protection against storm surges and coastal erosion.
