Obsolete oil rigs in the Gulf of Mexico have much to offer in the marine environment. Alas, federal law requires rigs' removal. "Most of the bottom is mud, so oil rigs provide the only hard bottom on which marine animals can settle and hunt for food," notes marine biologist Paul Sammarco in the Washington Post. "Once a rig is moved in any way, an entire ecosystem is gone." Sammarco is the author of a new study in Marine Biology on the ecological effects of rigs in the Gulf.

For more on the potential to create artificial reefs in the Gulf of Mexico, see this report by Michael DeAlessi. See also this information from the Department of the Interior.