Researchers have found new examples of the strange singled-celled creatures called xenophyophores more than six miles beneath the surface of the Pacific in the Mariana Trench. At more than four inches in length, they are perhaps the largest single-celled organism on Earth. These protists make a living by sifting through sediments and can accumulate high levels of toxic metals like uranium, lead, and mercury. Read more at LiveScience.

Image: Lisa Levin & David Checkley, Scripps Institution of Oceanography