The lowly oyster, a tasty delicacy to seafood lovers but a curiosity to more squeamish diners, is also the backbone of marine life along the U.S. Gulf Coast and among the most vulnerable creatures now threatened by a giant oil spill.
The region's oyster beds are the vital foundation of a commercial and recreational fishing industry -- including shrimp, crabs and other shellfish -- that generates billion in annual revenues, according to one recent estimate.
The networks of reefs built up in shallow waters by these unassuming bivalves are like the Gulf of Mexico equivalent of the Caribbean's coral reef system, only with oysters at the base of the pyramid instead of live coral.
In addition to providing shelter and food for a complex web of undersea species, the way coral reefs do, oyster beds serve a number of other important functions by virtue of their proximity to land.
"It is not only the economic engine of this region, it is a real indicator of the environmental and ecological health of the Gulf Coast area," said Jamie Rappaport Clark, executive vice president of the conservation group Defenders of Wildlife and former head of the U.S. Fish and Wildlife Service.
Oyster beds form undersea breakwaters that buffer shorelines and wetlands from erosion due to storm surge, helping preserve a habitat for birds and land animals. At low tide, exposed oyster banks themselves offer a feeding ground for some birds.
And as filter feeders, oysters constantly strain the water of impurities for the estuaries, bays and marshlands that lie behind them, a characteristic that also makes the oyster reef particularly sensitive to contamination.
oyster - ústřice
reef - útes
unassuming - nenáročný, skromný