Reuters: Russian and U.S. oceanographers studying the impact of global warming on the Bering Strait in late August enjoyed seas on some days that were so calm their ship made the only ripples. But the serenity of the seascape belied increasingly turbulent waters for scientific research as countries exert sovereignty over Arctic territory and Big Oil boosts exploration efforts. It has complicated life for Kathleen Crane, as she and her colleagues coordinate dozens of researchers in the …