CSS3Pie trigger
Menu  University of Minnesota

Take a look at some of the billions of organisms that keep our soil healthy

   
Streptomyces (Image 1 of 12)

Streptomyces bacteria are plentiful in soil, and the richest known source of antibiotics. They produce a molecule called geosmin, which is behind the earthy smell after rainstorms — and the earthy taste of beets. Some research suggests that in areas near intensive animal agriculture, antibiotics used in livestock end up in soil and impact bacteria and their communities. Source: Wikimedia Commons/public domain

   
Pseudomonas (Image 2 of 12)

The bacterium Pseudomonas aeruginosa can cause disease in humans, but it can also help to break down petroleum hydrocarbons and accelerate plant growth. Bacteria in soil also transform atmospheric nitrogen into ammonium, a plant nutrient. Source: Wikimedia Commons/public domain

   
Nematode (Image 3 of 12)

Acrobeles complexus is a nematode, or roundworm, that’s common in soil. Acrobeles feeds on bacteria, which can improve plant growth and are frequently found in decaying plant roots. Soil nematodes feed on bacteria more than 3.6 kilometers (2.2 miles) below the Earth’s surface, deeper than any known animal. Source: Tiago Pereira, UC Riverside

   
Mycorrhizal fungi (Image 4 of 12)

Mycorrhizal fungi live in or outside of plant roots. The fungi help the host plants acquire nutrients from soil and the plants reward the fungi with sugar. Arbuscular mycorrhizal fungi reproduce with spores and are among the most abundant organisms in many soils. Source: Arbuscular mycorrhizal fungus (AMF) ~100x by Marc Perkins, from Flickr, licensed under CC BY-NC 2.0

   
Ciliophora (Image 5 of 12)

Ciliophora are a kind of protist commonly found in soil that mainly eat bacteria. Researchers have described more than 1,500 species of ciliophora, although many more exist. Some soils contain dozens of species in one place. Source: Tashiror/Microbewiki

   
Rotifer (Image 6 of 12)

Bdelloidea are a type of rotifer — microscopic animals that beat hairlike cilia on their heads to move through water. They appear to play an important role in nutrient cycling in the soil, but ecologists don’t know what exactly that role is. Interestingly, Bdelloid rotifers are all female, and are thought to have survived without sexual reproduction for millions of years. Source: Bdelloidea sp. by Donald Hobern, from Flickr, licensed under CC BY 2.0

   
Springtail (Image 7 of 12)

Poduromorpha are a type of collembola, a group of invertebrates commonly known as springtails. They use sophisticated engineering to propel themselves several times the length of their bodies, and are important in soil decomposition processes. Source: Neanura muscorum by Andy Murray, from Wikimedia Commons, licensed under CC BY-SA 2.0

   
Tardigrade (Image 8 of 12)

Nicknamed “water bears,” tardigrades are found everywhere. They eat bacteria and other microscopic organisms. Tardigrades are described as the toughest creatures on Earth. They can withstand extreme drought and cold; often pioneer new, harsh environments; and have survived in space. Source: SEM image of Milnesium tardigradum in active state by Schokraie E, Warnken U, Hotz-Wagenblatt A, Grohme MA, Hengherr S, et al. (2012), from Wikimedia Commons, licensed under CC BY 2.5

   
Pillbug (Image 9 of 12)

Armadillidium vulgare, also known as the pillbug, is found around the world. Pillbugs eat dead plants, seeds and other materials in soil. They may limit how much carbon is released from the soil — potentially slowing climate change. Source: Armadillidium vulgare by Franco Folini, from Wikimedia Commons, licensed under CC BY 3.0

   
Mite (Image 10 of 12)

Tectocepheus velatus is a common mite in soils. Mites can be the last indicator in heavily disturbed soils of what was there before — and an indicator that reconstructing the previous vegetation and landscape conditions might still be possible. Source: Tectocepheus velatus from Soil Biodiversity UK, licensed under CC BY-NC-SA 3.0

 

   
Flower longhorn beetle (Image 11 of 12)

The adult flower longhorn beetle spends its spring and summer eating nectar and pollen. Beetles — and there are many of them, representing one-fifth or more of all known living speciesdecompose organic matter and improve soil fertility, while the larvae live in, and help decompose, dead trees. Source: Flower longhorn beetle by Katja Schulz, from Wikimedia Commons, licensed under CC BY 2.0

   
Earthworm (Image 12 of 12)

Lumbricus terrestris is the common earthworm. It eats dead plant material, excretes nutrient-rich casts that enrich the soil, and its burrows aerate soil and improve water flow. Although it is not native to New York, it is considered beneficial to some soil ecosystems, particularly in agriculture. While the common earthworm is not a threatened species, habitat loss, agricultural tillage and certain pesticides are all thought to harm earthworm populations. Source: © iStockphoto.com/igreen_images

 

Long overlooked as just dirt beneath our feet, soil has taken on increasing importance as we recognize its fundamental role in everything from agriculture to climate change to human health. So, too, with the organisms that call it home.

Soil is filled with more biological diversity than any other habitat on Earth. Its food web consists not only of worms and beetles and other well-known, easily visible animals, but also microscopic organisms from bacteria to fungi to protists. They all play a vital role in keeping soil healthy. They help nutrients move through the soil. They are responsible for moving, storing and filtering water. They capture carbon and other greenhouse gases. They support healthy plant growth.

And that’s just scratching the surface. It’s the living organisms, it turns out, that make soil soil rather than dirt.

From intensive agriculture to mining, human activities have compromised the health of soil and its inhabitants, to the point that researchers and global institutions including the United Nations are raising alarm about the speed at which the world is losing fertile soil. Pesticides, soil tillage, loss of organic matter, habitat loss and changes in how land is used generally are all key threats to soil biodiversity, although it’s virtually impossible to pinpoint specific threats to individual soil organisms.

“It is really hard to determine or see which fungus killed a bacterial-feeding nematode,” says Diana Wall, soil ecologist at Colorado State University and a member of the National Academy of Sciences, because of the very fact that it all happens underground. That is why, she adds, “destruction of their soil habitat where they evolved is the biggest threat.”

Increasingly, however, some are treating soil with greater care — through regenerative agriculture, for example — and working to build it back where it has been degraded. And researchers around the world are investigating what lives in soil, what makes those organisms healthy, and how we can best protect them. Projects like the the Global Soil Biodiversity Initiative, African Soil Microbiology Project, China Soil Microbiome Initiative, Biome of Australia Soil Environments (BASE) in Australia, sWORM, and Land Use/Cover Area frame statistical Survey (LUCAS) in Europe have been characterizing, or applying knowledge related to, soil biodiversity — essentially taking censuses of below-ground organisms around the world. Their rationale: The more we know about life underground, the more we can do to preserve it.

In 2014, researchers documented about as much biodiversity in the soil in New York City’s Central Park as anywhere else in the world. Here, we look at some of the kinds of organisms that are known or thought to live in the famous park. View Ensia homepage

Editor’s note: Thank you to Elizabeth Bach, Valerie Behan-Pelletier, Erin Cameron, Felicity Crotty, Noah Fierer, Peter Groffman, Kelly Ramirez and Diana Wall for sharing their expertise.

Post a Comment

You care about environmental issues. So do we!

Sign up now to get the latest stories about your environment delivered to your inbox once a week.

You’re in! Watch your email for weekly links to environmental stories that expand your mind — and change your world.