These little life forms – known as zooplankton – are essential to life as we know it on Earth. Marine biologists usually study these creatures in relatively shallow water. But they wanted to know more about the populations in deeper water, between one and five kilometers down.

Scientists on research cruise in the Bermuda Triangle used specially designed nets to capture fragile sea creatures in deep water. It is part of an effort to produce a global inventory of zooplankton by 2010.

The 28 experts from 14 countries who were on board identified an incredible variety of zooplankton – at least 500 species — but relatively few in number compared to the uppermost ocean layer. While still at sea, they sequenced the DNA of 220 of them. Some were less than a millimeter long. Others, including some of the jellyfish, were three to four centimeters in length.