02 Nov Pollution abatement, oyster-style

You may not want to eat them after seeing this, but oysters have a prodigious ability to filter polluted harbour waters. Watch what the laboratory oysters in this time-lapse video accomplish in just 90 minutes:

Federal and state agencies in the US, together with non-profit groups and academic researchers, are enlisting oysters in their efforts to restore the badly degraded waters of Chesapeake Bay, between Virginia and Maryland.

Oysters were once abundant in the bay. As young oysters settled and grew on the shells of old, they formed extensive reefs. In the 19th Century, researchers estimate, oysters could filter the entire volume of the Chesapeake Bay—68,137,412,112 cubic metres, about twice the volume of the Bras d’Or Lake—in as little as five days.

Over-harvesting, disease, falling salinity due to runoff over impervious concrete and asphalt surfaces, and increased sedimentation from runoff have beaten Chesapeake Bay oyster numbers down to less than 1% of their former abundance. It takes the current population a year to filter the same volume of water.

Researchers hope to rebuild the Chesapeake’s oyster population by encouraging the growth of new reefs.