Oceans, land, and deep subsurface: how is life distributed across environments?

We looked at how global biomass is distributed between taxonomic kingdoms. How is it distributed between environments?

The visualization here provides a snapshot of how life spans across the planet's environments. This summary is based on the findings of research by Bar-On, Phillips & Milo published in the Proceedings of the National Academy of Sciences (PNAS).[1]

There are three high-level habitat environments: land, marine, and deep subsurface environments. Deep subsurface environments can be terrestrial or below the ocean floor, but represent habitats deep below the surface – extending from around 50 metres to thousands of metres below the surface.[2]

Most of life exists on land — 86% of biomass. This is because almost all plant life – mostly trees – is terrestrial. The authors estimate that marine plants, for example seaweed, make up less than 1 billion tonnes of carbon. This is less than 0.2% of total plant biomass.[3] Most bacteria and archaea exists in the deep subsurface, meaning 13 percent of global biomass thrives in this environment.

Despite dominating our planet in terms of area and volume – taking up more than 70% of global surface area – the oceans are home to just 1% of biomass. But they do dominate the animal kingdom: 78% of animal biomass lives in the marine environment.

With lifeforms ranging in size from the microscopic cellular level to large lifeforms that span tens of hectares,[4] it is impossible to contextualize life on Earth through experience or intuition alone.

Just look at the viruses that live in the sea: while each one of them is tiny, if we placed all the viruses end-to-end they would stretch for 10 million light years. That is around 100 times the distance across our own galaxy.[5] On land the scale is just as mindblowing: there are more than 1016 prokaryotes in a ton of Earth's soil – orders of magnitude more than the 'mere' 1011 stars in our galaxy.[6]

Looking at the big numbers allows us to understand our planet and our place in it.

Endnotes

1] Bar-On, Y. M., Phillips, R., & Milo, R. (2018). The biomass distribution on Earth. Proceedings of the National Academy of Sciences, 201711842. Available at: [http://www.pnas.org/content/115/25/6506.

2] Parnell, J., & McMahon, S. (2016). [Physical and chemical controls on habitats for life in the deep subsurface beneath continents and ice. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 374(2059), 20140293.

[3] Total plant biomass is 450 billion tonnes of carbon, so in a maximum case: (1 billion tonnes / 450 billion tonnes) * 100 = 0.02 percent.

4] Pando (a tree), also known as the 'Trembling Giant' [is a colony of aspen in Utah and named the world's largest organism. It is determined to be a single living organism based on identical genetic markers and a single underground root system.

5] Suttle, C. A. (2005). [Viruses in the sea. Nature, 437(7057), 356-361.

6] Curtis, T. P., & Sloan, W. T. (2005). [Exploring microbial diversity--A vast below. Science, 309(5739), 1331-1333.

Where this page came from

This page was imported from Our World in Data. “Oceans, land, and deep subsurface: how is life distributed across environments?” by Hannah Ritchie (April 26, 2019), published by Our World in Data under CC BY 4.0. Changed here: set as a page, its interactive charts shown as pictures. Data from third parties keeps its own licence.

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