Scientific Breakthroughs

Earth May Be Home to 1 Trillion Species: Study

Earth May Be Home to 1 Trillion Species -Study
PHOTOGRAPH: Department of Microbiology and Ecosystem Science, University of Vienna | Photo shows bacteria on the surface of a mycorrhizal root tip, in a matrix of mucus and soil.

A new study shows Earth may be home to around 1 trillion species, only .001 percent of which has been identified. The data used in the study represented over 5.6 million microscopic and non-microscopic species from all over the world.

After poring over voluminous datasets on microbial, plant and animal communities from academic, government, and science sources, biologists at Indiana University came up with the largest compilation of its kind. The data covers 35,000 locations across the world’s oceans and continents, with the exception of Antarctica.

The datasets they used were combined with ecological models and new ecological rules for how biodiversity relates to abundance. The earth species number — a new and rigorous estimate of the microbial species on Earth — is indicated in the published work appearing in the Proceedings of the National Academy of Sciences.

The study’s authors are Jay T. Lennon, an associate professor in the IU Bloomington College of Arts and Sciences’ Department of Biology; and Kenneth J. Locey, a postdoctoral fellow in the same department. Lennon described the process of estimating the number of species on Earth “among the greatest challenges in Biology.”

Inclusion of Microbial Species

Other researchers have previously taken on the challenge but largely disregarded microbial species or microorganisms. Tools were also lacking until recently to truly estimate microbial species, which are too small to be seen by the naked eye. These include bacteria and archaea, as well as certain fungi.

A single gram of soil contains a billion organisms. Microbial sampling over the past years has entailed increased efforts.

The results may be seen in a number of collections. These include the National Institutes of Health’s Human Microbiome Project’s human-related microorganisms; marine microorganisms in the Tara Oceans Expedition; and aquatic, terrestrial and host-related microorganisms of the Earth Microbiome Project.

Tons of new information were gathered by new genetic sequencing technology. The data has been collected to answer big questions. The study brings into focus, for instance, just how powerfully biodiversity changes across scales of abundance.

Understanding the Scope of Life on Earth

The work was sponsored by the National Science Foundation. The main task is to fill major gaps in humanity’s knowledge about earth’s biodiversity. The foundation has set a 2020 timeline to accomplish its mission.

Simon Malcomber is the director of the NSF’s Dimensions of Biodiversity program. He says the research underscores how much diversity still has to be unraveled. According to the Earth Microbiome Project, a  global multidisciplinary project whose aim is to identify microscope organisms, less than 10 million species have been cataloged.

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