There are 57 billion nematodes for every human

There are approximately 57 billion nematodes for every human being on Earth: this is one of the results that came from a study carried out by Professor Byron Adams of Brigham Young University. And yet, all the existing nematodes in the world form a total biomass equivalent to about 300 million tons, about 80% of the total mass of all the current human population.

Published in Nature, the study focuses on nematodes, a phylum of microscopic small worms that inhabit a vast range of environments. In general, the length of a nematode can range from 0.1 to 2.5 mm and the thickness can range from 5 to 100 micrometers (one micrometer is one-thousandth of a millimeter), although there are some exceptions with much more pronounced lengths.

More than 25,000 species have been classified but the strongest suspicion of biologists is that this number is strongly inexpressive of the total number of nematode species that could exist in the world, and this new study is not in part a new confirmation. In recent years these animals are gaining more and more importance in terms of research so that more and more experiments on nematodes are carried out in very different sectors.

It has also been discovered that nematodes play a fundamental role in terms of the soil’s carbon and nutrient cycle and that they can also strongly influence CO2 emissions in the air. Thus understanding more about these tiny organisms on a global level is fundamental.

The researchers led by Adams took 6759 soil samples from different environments, from the tropical rain forest to the Arctic tundra, and collected various data regarding the nematodes they found in the same samples.
With this data, they built models to understand the global abundance of these organisms. They also discovered that the regions with the greatest abundance of nematodes are the sub-arctic regions, with 38% of the total.