U.K. researcher says area where marine life has difficulty surviving is worse than expectedUnderwater robots have found that a vast, oxygen-depleted "dead zone" in the Gulf of Oman is now the largest such area in the world. Scientists have known about the zone for around 50 years, but until recently they have not been able to collect very much data due to piracy and conflicts in the region. They sent two human-size robots known as seagliders into the area for eight months, and the vessels ventured into previously inaccessible areas. The seagliders found a zone with little to no oxygen...