Oysters getting a home in Presidio; Man-made reef aims to increase biodiversity in tidal wetlands; Enticing oysters to Presidio s Crissy Field takes a bit of science and engineering
Jonathan Young stood chest-deep in the brackish waters of the Presidio's Crissy Marsh and tugged on a rope tied to a glass buoy. A cement dome emerged from deep in the sediment, laden with algae and the shells of Olympia oysters.
The dome, twice the size of a bowling ball and three times as heavy, may seem an odd structure on which to place the hopes of a long-planned wildlife restoration project, but this is no ordinary dome.
Its rough walls are embedded with iridescent oyster shel...