They are everywhere, from boiling high-pressure vents in the deep sea, to hyper-saline desert lakes, to the bristles of your toothbrush. But scientists have found the diversity of the single-celled organisms that dominate the planet extremely difficult to study–when it comes to microbes, it’s difficult to even decide what a species is, let alone how many species there are on Earth. But with the help of a science called metagenomics, the study of the world’s tiniest creatures is taking a huge leap forward. Researchers took a 9,000-kilometer voyage from the Arctic Circle to the South Pacific to collect seawater samples, then used rapid sequencing methods to “read” the DNA of the microbes they collected. Powerful statistical models are helping researchers turn the dataset, which contains billions of DNA base pairs, into a picture of the microbial diversity in the earth’s oceans. Though they represent the tip of the iceberg, recent discoveries from the project include insights into genetic adaptation to environmental changes and a host of special proteins that offer protection from ultraviolet light.
Source: L. Gross, Untapped Bounty: Sampling the Seas to Survey Microbial Biodiversity. PLoS Biology 5(3): e85. doi:10.1371/journal.pbio.0050085. Image: Sites sampled by the Sorceror II, a research vessel that traveled 9,000 km to survey the microbial diversity of the oceans. From PLoS Biology.