Loss of Arctic Sea Ice Means New Era of Species Movement

The disappearance of Arctic sea ice will open up more than just a passage for ships: Scientists predict that it also will lead to a large-scale transfer of shellfish, snails, and other animals from the Pacific Ocean to the Atlantic. Writing in the journal Science, researchers say that the movement of species across the pole will resume a migration that came to an end 3 million years ago, during the mid-Pliocene, when colder conditions halted a transfer of mollusks and other marine creatures from the Pacific to the Atlantic. The scientists said that with a largely ice-free Arctic Ocean expected by mid-century, about a third of shallow-water shellfish species in the Bering Sea could potentially spread to the Atlantic. The species transfer is one-way because the North Pacific marine fauna tend to be bigger and stronger and the predominant water flow is northward through the Bering Strait across the pole. The invasion is not expected to destroy native species, but rather to introduce more species, hybrids, and greater competition to the North Atlantic.