[Animals] A hidden world: these are the microscopic animals that inhabit the most diverse forests in the world

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Grab a handful of soil from the Black Forest in Germany, the Tongass Forest in Alaska, or the Waipoua in New Zealand. Bring it up to your eyes. Do you see? Earth, of course.
Smooth, fertile, dark as cocoa powder. Also, pine needles and decaying leaves. Moss or lichen particles. The pale accordion of an inverted mushroom. Perhaps an earthworm squirming to escape the light, or an ant bewildered by the sudden change in altitude.

Sue Grayston knows there is much more.

Grayston's consecration to the land began in her backyard. When she was a child, in Stockton-on-Tees, England, she helped her mother plant seeds and tend her garden.

Constellations of creatures that inhabit the ground

At university, where Grayston had access to microscopes, his attention was drawn to constellations of ground-dwelling creatures too tiny to study with the naked eye. He then he knew that he had found his calling.

After earning a Ph.D. in microbial ecology from the University of Sheffield in 1987, she worked for an agricultural biotechnology company in Saskatoon, Saskatchewan, Canada, after which she obtained a research position at the Macaulay Land Use Research Institute (now the Land Use Research Institute). James Hutton) in Scotland. There she collaborated with botanical ecologists and put down the roots of a project that would keep her engrossed for much of her career: the complex links that exist between the smallest inhabitants of the soil and the largest, microbes and trees.

Forming your own kingdom
By combining groundbreaking field studies with sophisticated genetic sequencing techniques, Grayston and other ecologists have created a much richer portrait of a society hiding on the forest floor; a community that is generally invisible and whose absence would collapse the ecosystem.

“ALTHOUGH MUCH OF THE BIODIVERSITY IS UNDERGROUND, WE DON'T KNOW MUCH ABOUT IT”, she ACKNOWLEDGES GRAYSTON. "HOWEVER, THAT STARTED TO CHANGE OVER THE LAST COUPLE OF DECADES."

Deep below the trees, strings of filamentous fungi join their roots to form mycorrhizal networks through which trees exchange water, food, and information. Single-celled amoebae coalesce to create a shape-shifting mass known as slime mold, which flows in or with the soil and traps bacteria and fungi.

Springtails – tiny arthropods – swarm aimlessly; sometimes they catapult more than 20 times their length in a fraction of a second. Oribatid mites stumble across what to them might be mountains and canyons, but they don't make more than the equivalent of half a bowling alley in their lifetime, which usually lasts about a year and a half.

OTHER CREATURES ARE SO TINY THAT THEY CAN ONLY MOVE BY WRIKING OR “PADDING” THROUGH THE THIN LAYERS OF WATER COVERING PLANTS AND GROUND PARTICLES. THESE ODD BEINGS INCLUDE TRANSPARENT NEMATODES, SPRINKLE-SHAPED ROTIFERANS WITH SWIRLING CROWN OF HAIRY FIBERS THAT PULL FOOD INTO THEIR VASE-LIKE BODIES, AND TARDIGRADES THAT LOOK LIKE GUMMY BEARS, BUT WITH EIGHT-CLAWED LEGS AND SPINED SUCTION TUBES INSTEAD MOUTH.

Smaller still are the protozoa: a diverse group of single-celled organisms that sometimes move by waving their many appendages or contorting their gelatinous interiors. On the forest floor there are also many types of bacteria and archaea, which, although they are similar in appearance to the former, form their own kingdom.

A single gram of forest soil can contain up to a billion bacteria, a million fungi, hundreds of thousands of protozoa, and nearly a thousand nematodes.
The earth is not, as was once believed, an inert substance that trees and plants cling to in order to extract whatever they need. It is increasingly clear that it is a dynamic network of habitats and organisms; an immense and changing fabric created with the threads of countless species. The earth itself is alive.

What happens above, is reflected below
Grayston and other environmentalists argue that this modern vision calls for substantial changes to forestry: they found that clearcutting is a practice that causes more extensive and lasting damage than previously imagined. It is not enough to take into account that cutting down a tree alters the forest from the trunk up; to be truly sustainable, forestry must also deal with the consequences that affect everything below.

Billions of years ago our planet had no land, only a rocky crust that rain, wind and ice gradually wore away. As microbes, fungi, lichens, and plants po[CENSORED]ted everything, they accelerated the erosion of the rock by gouging it out, dissolving it with secreted acids, and breaking it down with roots.

When the Earth had no land
At the same time, decaying life enriched the mineral crust with organic matter. The first recognizable forest lands appear in the fossil record during the Devonian period, between 420 and 360 million years ago.

Today, the planet's soils continue to be present in all ecosystems. The forest floor is full of essential nutrients like carbon, nitrogen, phosphorous and potassium. Without the daily activities of tiny creatures, many of those items would be inaccessible, Grayston and his colleagues point out.

When plants photosynthesize and convert the sun's energy into carbon-filled molecules, they exude some of these compounds through their roots into the soil, where certain organisms consume them. In return, mycorrhizal fungi and certain root microbes help the roots absorb water and nutrients and convert chemically recalcitrant forms of nitrogen into molecules they can use.

Once plants wither and die, worms, arthropods, fungi, and microbes break down those tissues into smaller elements and return their nutrients to the soil. At the same time, the continuous movement of tiny animals mixes different layers of soil, distributes nutrients and maintains ventilation. By digesting huge amounts of soil, worms, slugs, and arthropods soak the soil in organic matter and help particles stick together, improving soil structure.

The forest as a single 'All'
In 2000, while working for the Macaulay Institute, Grayston traveled to Tuttlingen, a German city on the Danube River, to investigate Black Forest soils with his colleagues. Noted for its forested mountains, this 6,000-square-kilometer region in the southwestern part of the country has long been prized by the mining and logging industries.

The researchers visited some sites noted for their 70- to 80-year-old beech trees, with supple silvery bark and twisted trunks. Some of the areas the team examined have been subject to logging for a long time, while others were more or less intact.

Grayston used a sampling auger to extract soil from different sites in the forest, stored the samples in ice chests and brought them back to Scotland for closer study. Laboratory tests and cell cultures revealed that intensive extraction had significantly reduced the abundance of microbes in one area of the forest.

Although at the time these were promising connections, the details were rather fuzzy. However, over the past two decades, Grayston and other scientists have learned much more about the interdependence of plants and soil microbes, and the importance of these relationships to forest ecosystems as a whole.

Uniform logging had decreased soil biodiversity
Grayston moved to Vancouver in 2003 to become a professor of soil microbial ecology at the University of British Columbia, where she has worked ever since. This is where she and her collaborators have delved into research on how different types of forestry transform soil microbial communities.

Much of her studies compare three types of felling:

Standard (uniform), which removes all trees from a given site
With reservations, in which certain groups are preserved
Selective, which removes specific individual trees, maintaining an even distribution
To test the health of the soil, Grayston and her colleagues buried nylon mesh bags filled with fine roots in patches of forest that had been logged in different ways. They left the roots to be decomposed by tiny animals, fungi, and microbes, digging them up within a few months to several years. In the laboratory, the researchers performed various tests to identify the organisms associated with the roots and determine what their level of activity had been.

In many cases, uniform felling had decreased soil biodiversity and impaired nutrient cycles. Intensive logging also frequently altered the po[CENSORED]tions of the soil communities, allowing a more or less small number of species to dominate. However, not all extraction methods were found to be equally harmful.

Microbial abundance, diversity, and activity remained relatively high in areas that had uniformly lost trees. In regions that had been reduced to groups of trees, the researchers only found equally robust and lively communities of microbes in close proximity to them. The farther they went, the less life there was on the ground.

Damage goes in a range of 10 meters
Related research studying the flux of carbon through tree roots revealed that a tree's or group's zone of influence—where it supplies carbon-rich molecules to microbes and other organisms tiny – extends about 10 meters on average. The benefit of keeping a few trees on empty land, even in large groups, is limited.

Outside a range of 10 meters around these plant islands, microbial po[CENSORED]tions will be impaired. Grayston explains that selective logging is better for soil health, as it typically conserves a tree almost every 15 meters, allowing their roots and respective buffer zones to overlap to provide carbon for the trees. microbes.

Although selective logging methods are gaining prominence in some regions of the world, standard logging is still widely practiced in North America because it is more efficient, costs less, and requires less complex machinery. For the same reasons, reserve logging is often preferred over selective logging.

What awaits forests in the near future?
“WE MUST RECONSIDER OUR FORESTRY PRACTICES”, CONSIDERS PETR BALDRIAN, ENVIRONMENTAL MICROBIOLOGIST AT THE INSTITUTE OF MICROBIOLOGY OF THE CZECH ACADEMY OF SCIENCES. UNIFORM LOGGING IS VERY ECONOMIC, BUT IT HAS A HUGE COST TO THE LAND; WE HAVE TO FIND A BALANCE BETWEEN THE NEEDS OF THE INDUSTRY AND THOSE OF THE FOREST”.

Reflecting on the future of the planet's forests – and its soils, in particular – Grayston is both excited and concerned. She is excited by the great mystery of everything that remains to be discovered; which is basically why she decided to study microscopic life. "We've come a long way," she says, "but we still don't know who is really active at certain times or which specific organisms are essential for different processes in the soil."

At the same time, he is concerned about the continuing deterioration of forests due to over-logging, poor land management and the effects of climate change. Because the Earth's overlapping ecosystems are so interconnected and so critical to the survival of complex life, the damage we do to the planet's trees and soils ultimately affects us as well.

“IF WE DIDN'T HAVE THE MICROORGANISMS IN THE SOIL, THE GARBAGE WOULD BE UP TO THE KNEES,” SAYS GRAYSTON. “WITHOUT THEM, LIFE ON EARTH WOULD END. THEY DON'T NEED US FOR ANYTHING, BUT WE WOULDN'T GET VERY FAR WITHOUT THEM.”

https://www.ngenespanol.com/animales/que-animales-microscopicos-viven-en-la-tierra-de-los-bosques/