From Quanta, August 27, 2019:
Soil’s Microbial Market Shows the Ruthless Side of Forests
Beneath the green vegetable world we see is a dark microbial world we don’t. The crops we eat, the forests that sustain us and most other life forms, even the regulation of Earth’s climate — all benefit from a shadowy network of fungi and bacteria that mobilize soil nutrients and trade them with plants for sugars and fats. And yet the workings of this subterranean society are almost unknown to scientists. For example, researchers just mapped for the first time the global distribution of three major groups of these microbes. Even in 2019, what lies beneath our feet remains a true scientific frontier.
Despite this epistemological murkiness, public interest in the underground ecosystem has exploded. TED talks and bestselling books extol the benevolent, cooperative “wood wide web” of subsurface organisms that communicate, share nutrients and sustain each other.
Toby Kiers, an evolutionary biologist at VU University Amsterdam, is at the vanguard of a new generation of scientists questioning that gauzy view. Through innovative and groundbreaking studies, Kiers and her collaborators have gathered evidence that plants and their fungal conspirators are not just cooperating with each other but also engaging in a raucous and often cutthroat marketplace ruled by supply and demand, where everyone is out to get the best deal for themselves and their kind.
Key to this picture is the revelation that the unseen underground world is just as complex, sophisticated and purposeful as the visible aboveground world we inhabit. Microbes are not simple, passive accessories to plants, but dynamic, powerful actors in their own right. Fungi can hoard nutrients, they can reward plants that are generous with their carbon reserves and punish ones that are stingy, and they can deftly move and trade resources to get the best “deal” for themselves in exchange.
Those are probably just the beginning of their talents. In a paper published in June, Kiers and her colleagues pioneered a method to illuminate the fungal marketplace in action — to make the invisible visible. The tantalizing research hints at a capability that has been suspected but never proved: that fungi might not be just nutrient traders but also sophisticated information processors.
Kiers is the first to admit that scientists have far to go in puzzling out the hidden rules of the tiny networked organisms that somehow support all the rest of us. “Doesn’t it strike you as odd?” she said. “We know so much about other types of networks. This is undoubtedly the most important network for our ecosystems, but we just don’t know anything about it. … It’s radically under-studied.”Coming up: making money fungi style.
Ancient Partners
When plants crept onto land some 500 million years ago, microbes were waiting. Fungi and bacteria struck up relationships with their new neighbors. Plants, after all, could do something most microbes could not: harness solar energy to split apart atmospheric carbon dioxide and construct energy-rich sugars and fats from the pieces. The microbes, in turn, had mastered the art of freeing up the nutrients that plants needed from the soil — phosphorus especially, but also nitrogen; there is evidence that microbes help plants gain access to water as well. Some 80 percent or more of today’s land plants form partnerships with fungi; still other plants partner with bacteria. If the soil were somehow purged of its microbes, the plant and animal worlds would take a big hit. The views of the great naturalist E.O. Wilson notwithstanding, it’s microbes, not insects, that run the world....MUCH MORE
