Even though scientists did not have a thorough record of viruses in the oceans, many of them assumed the number and variety of viruses would diminish from the equator toward the poles. Not so. A new study has vastly expanded the data set and shows the Arctic Ocean has a richer cast of viruses than other major oceans. “It's a hotspot,” says study member Matthew Sullivan, a microbiologist at Ohio State University. He thinks the reason is that the Arctic Ocean is a mixing pot of waters from the Atlantic and Pacific Oceans, global ocean conveyor belts and huge rivers that empty there. Also surprising is that viruses are largely concentrated in four other marine zones across the planet. “We just didn't know that before,” Sullivan says. “It could have been 20.”