Researchers have found that previous estimates about the total mass of life on our planet have been a little too generous, having to decrease the estimate by one third.
The study behind the discovery was published in the current online issue of the journal Proceedings of the National Academy of Science and was led by Dr. Jens Kallmeyer of the GFZ German Research Centre for Geosciences and University of Potsdam.
“About half of the world’s ocean is extremely nutrient-poor. For the last 10 years it was already suspected that subseafloor biomass was overestimated” explains Dr. Jens Kallmeyer the motivation behind his study. “Unfortunately there were no data to prove it.”
Now there is.
According to previous estimates, approximately one thousand billion tonnes of carbon were stored in living organisms, of which 30 percent was found in single-cell microbes living on the ocean floor, and 55 percent in land plants.
Kallmeyer’s team have had to revise the number after they collected sediment cores from areas that were far away from any coasts and islands. The work took six years to accomplish, and in the end showed that there were one hundred thousand times less cells in sediments from open-ocean areas than in coastal sediments.
With this new data in tow, the scientists were able to revise their estimate of the total biomass in marine sediments: instead of 300 billion tonnes of carbon, there are really only 4 billion tonnes of carbon stored in subseafloor microbes.
Source: Helmholtz Centre Potsdam