In other contexts, biomass can be measured in terms of the dried organic mass, so perhaps only 30% of the actual weight might count, the rest being water.

In 2018, Bar-On et al. estimated the total live biomass on Earth at about 550 billion (5.5×1011) tonnes C,[1] most of it in plants.

[4] The total live biomass of bacteria was once thought to be about the same as plants,[5] but recent studies suggest it is significantly less.

[1][6][7][8][9] The total number of DNA base pairs on Earth, as a possible approximation of global biodiversity, is estimated at (5.3±3.6)×1037, and weighs 50 billion tonnes.

[10][11] Anthropogenic mass (human-made material) is expected to exceed all living biomass on earth at around the year 2020.

[12] An ecological pyramid is a graphical representation that shows, for a given ecosystem, the relationship between biomass or biological productivity and trophic levels.

The primary producers take energy from the environment in the form of sunlight or inorganic chemicals and use it to create energy-rich molecules such as carbohydrates.

This energy loss means that productivity pyramids are never inverted, and generally limits food chains to about six levels.

Terrestrial biomass generally decreases markedly at each higher trophic level (plants, herbivores, carnivores).

Zooplankton comprise the second level in the food chain, and includes small crustaceans, such as copepods and krill, and the larva of fish, squid, lobsters and crabs.

Baleen whales can consume zooplankton and krill directly, leading to a food chain with only three or four trophic levels.

Among the phytoplankton at the base of the marine food web are members from a phylum of bacteria called cyanobacteria.

[16] In terms of individual numbers, Prochlorococcus is possibly the most plentiful species on Earth: a single millilitre of surface seawater can contain 100,000 cells or more.

[18] The bacterium accounts for an estimated 20% of the oxygen in the Earth's atmosphere, and forms part of the base of the ocean food chain.

Recent estimates used an average cellular biomass of about 20–30 femtogram carbon (fgC) per cell in the subsurface and terrestrial habitats.

Most animal biomass is found in the oceans, where arthropods, such as copepods, account for about 1 billion tonnes C and fish for another 0.7 billion tonnes C.[1] Roughly half of the biomass of fish in the world are mesopelagic, such as lanternfish,[25] spending most of the day in the deep, dark waters.

Wild terrestrial mammals account for only about 3 million tonnes C, less than 2% of the total mammalian biomass on land.

[1][30] According to a 2020 study published in Nature, human-made materials, or technomass, outweigh all living biomass on earth, with plastic alone exceeding the mass of all land and marine animals combined.