AP Photo/John L. Russell
In this Tuesday, April 22, 2014, photo, the 140-foot icebreaker Biscayne Bay cuts through thick ice on the St. Mary's River on its way to escort vessels north to the Soo Locks, in Sault Ste. Marie, Mich. The U.S. Coast Guard spent more than four months breaking ice to open shipping lanes throughout the Great Lakes. Canada has sent two icebreakers to the High Arctic to gather scientific data in support of its plan to bid for control of the sea floor under and beyond the North Pole.