Which species has the largest biomass

Biomass Census: The Impact of Humans on the Biosphere

Scientists have carried out a "census" of earthly life for the first time and have shown how profoundly people, who make up 0.01 percent of the biomass, have changed the biosphere

For the first time, scientists from the Weizmann Institute of Science and the California Institute of Technology have carried out a "census" of all living things on earth, but in the form of an estimate of the biomass of the various species. The study was published in PNAS.

That offers new comparisons that can be amazing. The 7.6 billion people who live today, with a biomass of just 0.06 gigatons of carbon (Gt C), are only a small fraction of the total biomass of 550 gigatons of carbon, about as much as termites, but they have life changed enormously on earth.

According to the biomass census, which is of course only a rough estimate with many uncertainties, plants dominate all other living beings. 82 percent of all living beings are plants, their biomass is 450 gigatons of carbon, plants predominantly live in rural areas. Trunks and stems make up 70 percent of plant biomass.

The bacteria rank far behind the plants. At 70 gigatons, their share in total life is 13 percent. Just like the archae with 7 gigatons, they are mostly found under the surface of the earth. With 12 Gt C, mushrooms have the third largest share of the biomass, the smallest with 2 GT C animals.

All other animals that live mainly in the sea make up just 5 percent of the biomass. Because relatively few plants live in the oceans, the marine organisms with 6 gigatons still only make up one percent of the total terrestrial biomass. 70 percent of marine biomass are microbes, especially bacteria and protists. 15 percent of them live in the deep sea, again largely bacteria and archae.

It is interesting that, according to the scientists, there are more "consumers" in the seas with 5 Gt C than "producers" with 1 Gt C, according to which the marine food pyramids are inversely compared to those on land, where there are significantly more "producers" than "consumers" " gives. The scientists attribute the inverse food pyramid in the sea to the higher productivity, which has to do with the fact that the life cycle of the "producers" is much faster than that of the "consumers".

A main focus of the study is on the impact of people on the rest of life. After humans have already had a significant influence on the climate, which is why people speak of the Anthropocene, they have also turned earthly life inside out in a short time and initiated the sixth mass extinction, which is advancing at breakneck speed and has perhaps wiped out half of the animals within a few decades. According to the estimates of scientists, the biomass of plants has decreased by half since the beginning of human civilization.

The biomass of humans (0.06 Gt C) is now ten times as large as that of all wild animals (0.007 Gt C). Farmed poultry alone - especially chickens - have a share of 0.005 Gt C, which is more than twice as large as that of wild birds (0.002 Gt C). And the biomass of all livestock, at 0.1 Gt C, not only exceeds that of humans, but also by far exceeds the biomass of all wild animals. It is different with the agriculturally used plants. They have a biomass of 10 Gt C, but only a share of 2 percent of the biomass of all plants.

Despite the tremendous changes in life caused by humans, their biomass is also small with regard to other living beings. The biomass of viruses or worms is three times that of humans - and that of fungi 200 times. (Florian Rötzer)

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