The North Atlantic water that flows into the Arctic is warming, melting the sea ice and changing the delicate Arctic ecosystem. In part 2 of our journey with NPI's A-Twain Mission, John follows oceanographer Arild Sundfjord, the leader of the A-TWAIN expedition, and sea ice physicist Angelika Renner as they track the changes in Arctic water temperatures over time by recovering and deploying a series of deep water moorings he’s been monitoring over the course of several years.