The biosphere is the place on Earth where life exists, with a total global biomass of at least three trillion tons. The biosphere is mainly composed of producers, with consumers and predators making up the minority. The Oxygen Catastrophe occurred about 300 million years after the evolution of photosynthetic microbes, converting the Earth’s carbon dioxide/nitrogen atmosphere to an oxygen/nitrogen atmosphere. Life probably colonized every corner of this planet billions of years ago.
The biosphere is defined either as “the place on the earth’s surface where life inhabits” (original definition by Edward Suess in 1875) or, in a narrower sense, only as the organisms themselves. Total global biomass is at least three trillion tons, probably more. The global total of aboveground woody biomass is about 422 billion tonnes.
Human biomass is about 500 million tons, slightly less than that of Antarctic krill, and biomass produced for human use exceeds three trillion tons. The bacterial biomass is estimated to be similar to that of plants. Complicating these measurements is that several researchers may publish “dry biomass” figures, omitting water weight, without explicit mention. In general, the quantities are greatest near the equator and least near the poles.
Since at least 2.7 billion years ago, during the so-called Oxygen Catastrophe, the biosphere has been intimately linked to the planet’s hydrosphere (oceans), lithosphere (crust) and atmosphere (air). The oxygen catastrophe occurred about 300 million years after the evolution of photosynthetic microbes, the ancestors of today’s cyanobacteria.
Oxygen is a byproduct of photosynthesis and huge amounts of it were released as photosynthetic organisms spread across the face of the Earth. The Earth’s carbon dioxide/nitrogen atmosphere has been progressively converted to an oxygen/nitrogen atmosphere, while much of the free carbon dioxide has dissolved into the oceans, precipitating as limestone, and cyanobacteria have converted it into oxygen. Many of the anaerobic organisms that lived at the time died out as a result, which is why the event is called a “catastrophe”.
The biosphere is mainly composed of producers such as algae, plants and photosynthetic bacteria. Consumers, such as herbivorous animals and fungi, make up the minority, with predators making up the least of all. In one unusual exception, however, 99% of the terrestrial vertebrate biomass consists of humans, their pets, and food animals. The biomass of marine vertebrates significantly exceeds this.
Almost, if not all, of the planet’s square meters are part of the biosphere. Except for the one-third of the earth’s surface covered by desert, ice floes or high-elevation mountains, plants grow just about everywhere, and where there’s plant life, there’s animal life. Life is also abundant in the oceans, where it lives mainly in the photic zone, where light reaches it, in the top 656 feet (200 m). However, life also extends to the deepest ocean trenches, where fish and shelled animals have been observed.
If bacteria are included, the biosphere is indeed extensive. Advances in microbe detection and deep drilling have revealed bacteria at least 5.6 miles (9km) below the surface, while balloons have found airborne bacteria at altitudes of 3.7 miles (6km). Life probably colonized every corner of this planet billions of years ago.
Protect your devices with Threat Protection by NordVPN
