Live Science, via Yahoo News...
If B-15A gets stuck, as it has before, researchers fear it could block sea ice behind it, thwarting animals that need to move from shore to the open sea.
B-15A is the largest chunk left of a bigger iceberg, known as B-15, that broke off the Ross Ice Shelf in March 2000. That initial frozen hunk was about the size of Jamaica. After B-15 broke apart, the chunk named B-15A drifted into McMurdo Sound, where it blocked ocean currents and caused other sea ice to build up, threatening wildlife.
Scientists predicted an imminent collision back in January this year. Instead, the iceberg ran aground and stalled out. Then it broke free in March. On the move again, it collided with the Drygalski ice tongue in April, forcing the redraw of Antarctica maps.