Image

No Swimming

A floating piece of ice in the Arctic Ocean matches the shades of white-sand beaches in tropical water, but the temperature would be quite a shock to anyone who was tempted to lay out on its surface. Thin edges of snow-covered ice push up above the surface, but it actually extends deep into the water, producing the gently deepening turquoise hues. The photo is from a 2004 expedition to the Arctic to deploy Ice-Tethered Profilers, instruments that drift with sea ice, collecting data and transmitting it directly back to shore via satellite. (Photo by Kris Newhall, Woods Hole Oceanographic Institution)