A ship carrying scientists and submarines is setting sail from Germany for the start of an unprecedented, years-long effort to explore the Indian Ocean. The ambitious expedition will delve into one of the last major unexplored frontiers on the planet, a vast body of water that's already feeling the effects of global warming. Understanding the Indian Ocean's ecosystem is important not just for the species that live in it, but also for an estimated 2.5 billion people in the region. The Ocean Zephyr is scheduled to leave Bremerhaven on Thursday for the Seychelles, where scientists will spend seven weeks surveying at depths of up to 2,000 meters (6,560 feet) using crewed submarines and remote-controlled submersibles. The Associated Press will provide live underwater video from the submarines during the expedition.