By Janet Raloff
Hand over hand, the scuba diving researchers felt their way down the offshore oil rig, blinded by water black with ocean detritus and marsh debris. They tried not to think about the 7-foot alligator patrolling the rig at the water’s surface, 15 miles from its swampy home. The scientists soon reached a place on the rig’s leg where 18 months earlier they had attached instruments that relayed information on undersea conditions. Loose cables provided the only sign of their $200,000 package, which had fallen silent almost 3 weeks earlier, on the night that Hurricane Katrina passed over this patch of the Gulf of Mexico.
Continuing down to the seafloor, 65 feet below the ocean surface, the divers began probing the muck with their hands. “We found bits and pieces of the instruments and the custom brackets that had held them on to the platform,” says Nancy Rabalais, executive director of the Louisiana Universities Marine Consortium in Chauvin.