Reuters: U.S. agencies on Sunday approved a plan to use remote-controlled underwater vehicles to seal a leaking oil well beneath a drilling rig that exploded and sank in the Gulf of Mexico last week. The well, 5,000 feet under the ocean surface off Louisiana’s coast, is leaking about 1,000 barrels of oil a day. The spill, which the U.S. Coast Guard has called “very serious,” could threaten the Gulf Coast’s fragile ecosystem if not contained. Four underwater vehicles have been deployed …