The world’s greatest power players include some much smaller titans than you’d expect. Armies of tiny creatures labor every day to shape the world, without most of us ever noticing. Here are ten creatures you can barely see—but you can’t live without.
Do you enjoy your skin not being unbearably sensitive? Do you like having enough red blood cells to oxygenate your blood? Hows that ability to control your bowels working out for you? If things are going well in those departments, thank the groups of bacteria that make vitamin B12. They’re the only ones in possession of the enzymes to make it work, and they generously supply the finished product to the rest of the world. Some soil bacteria even do this, despite not even needing the vitamin, because they live in symbiosis with the plants that do need it. Some bacteria have an equally symbiotic relationship with algae. And some cheerfully get chomped by animals, which we in turn eat to get the vitamins which keep us alive. If these bacteria ever went on strike, the world as we know it would be over.
This fungus may one day make your fuel. That isn’t news. People have been talking about biofuels made by letting either fungus or bacteria digest plant matter for a long time. G. roseum is just the fungal front runner, able to break down cellulose more completely than almost anything else. What’s impressive is the idea that G. roseum made the fuel you already use. According to microbiologist Gary Stobel, G. roseum is so good at breaking down cellulose, it calls into question whether fossil fuels came about due to age and pressure alone. Maybe the mushrooms did it. Maybe the only reason you’re driving is because you have access to millions of years of this fungus’s work.
We’ve come to accept, due to tireless educational efforts of yogurt companies, that not all bacteria are bad. That doesn’t mean we should welcome stuff like E. coli into our bodies—except that we do, every day. Our lungs, our eyes, our noses, our mouths all get a dose of bacteria which is not healthy. When researchers grew samples of human lung tissue with E. coli, about half the cells in the tissue culture died in a day. The next day, they tried it again, except they added bacteriophage viruses found in mucus. The tide of the massacre turned, and the bacteria were the ones getting killed off. The researchers speculate that this was not a new relationship, and that humans evolved with their protector viruses. It’s doubtful that humans are the only animals to employ viruses. Pretty much every macro-scale animal you see is probably protected by an army of tiny viruses.
Do you like bread? Do you like beer? Then you like wasps. Wasps are best known as the creatures that were so evil, they inspired the Alien franchise. They make paper nests and sting us if we get near them. They brainwash various animals and force those animals to get eaten alive by wasp larvae.
But they also do something else—they eat grapes. They eat grapes and other wild fruits, which are covered with yeasts. Being in the belly of a wasp doesn’t seem to do any harm to the yeast, even if the yeast stays in the wasp’s stomach all winter while the wasp is hibernating. The yeast also survives being puked up in spring for the wasp’s larvae to eat. The larvae mature, and, in the summer, when conditions are good enough to keep the yeast alive, carry the yeast out into the world again. Although not all yeasts survive the winter inside a wasp, the wasp is probably a big part of why there are so many wild yeasts in the world, and a big reason why our ancestors discovered the process of fermentation.
Most of these little critters are benign or beneficial. Methanosarcina is the monster in the mix. About 250 million years ago, the world heated up, and many of its inhabitants died off. Some think that this was due to geological activity—and volcanic activity at the time was pretty high. But some researchers noticed two things that happened just prior to the die-off. First, Siberian volcanoes dumped a lot of nickel into the world. Second, a certain genus of archaea (single-celled organisms distinct from bacteria), developed the ability to process its food and spit out methane quickly, via a gene transfer with another microbe. These archaea got a necessary resource, nickel, and a metabolic advantage and proliferated enough to heat the world to near-destruction. They also acidified the ocean, killing off a lot of marine life. They’re still alive. There but for an abundance of nickel go we.
We all know that krill are food for whales and whales are magic animals that fill us with wonder and make aliens stop attacking us in Star Trek movies, but making whales may be the least important thing krill do. Studies on brine shrimp (which are easier to raise and manipulate than krill but still swim like krill), show that when they swim in a herd their motion causes eddies in water. These eddies swirl up different layers of water, dredging up deep water and letting water from the surface get pulled downwards. If this process scales up, then the migrations of krill are what cause different layers of the ocean to mix. Food-rich deep water comes up to swirl around oxygen-rich shallow water. Cold water and warm water mix. The billions of krill swimming in the ocean may be responsible for a good chunk of ocean life, and perhaps some of the actual ocean currents.
Phytoplankton are at the bottom of the ocean’s food chain. Anything at the bottom of any food chain is important, because without large portions of the top of the food chain go missing, but we’re not thanking phytoplankton for a tuna sandwich, we’re thanking them for one half of our lives—or perhaps I should say one half of all the breaths we take. Trees get a lot of credit for the oxygen we breath because they’re big and pretty, but half of what we need comes from the tiny phytoplankton in the ocean. One type of phytoplankton alone, Prochlorococcus, counts as the most abundant photosynthetic cell on the planet. Messing with them (for instance by changing the temperature of their home) would be like going into space and putting a knot in your own oxygen hose.
The world needs nitrogen. No nitrogen, no protein. No nitrogen, no DNA. No nitrogen, no life. And it seems the world has nitrogen in abundance. Nitrogen makes up about 78% of the atmosphere. That’s all the nitrogen anyone could wish for, and none of the nitrogen anyone can use. Nitrogen in the atmosphere is nonreactive.
Unless we’re termites. Termites get a bad reputation because they destroy houses and spew methane into the atmosphere. What they also do is possess a gut filled with nitrogen-fixing bacteria, and transport that gut through the soil, distributing nitrogen everywhere. They’re not the only link that gets nitrogen from the air into soil, into plants, and into animals—but they are an essential one. To get an idea of how important nitrogen fixing is, the two chemists who figured out how to fix nitrogen in fertilizer are credited with saving 3.5 billion people from starvation. Termites have kept many times that many animals alive. Where’s their Nobel Prize?
If you believe some microbiologists, you have at least once in your life been soaked because bacteria decided it was time to make it rain. Certain bacteria have what’s called an ice-nucleating protein on their exteriors. When the bacteria are blown through the air, this protein encourages the formation of ice crystals at relatively high temperatures. The ice crystal nucleation is the first step in making it rain, which brings the bacteria down to the ground. Once they’ve multiplied, or when conditions turn unfavorable for them, they can lift back off the ground and start the weather cycle all over again. This is not a little flight followed by a gentle local shower. These organisms start in Antarctica, the Yukon, and the French alps, and travel all over the world by nudging patterns in global rainfall.
How many worms do you think there are per acre of land? Estimates differ wildly, but it ranges between a couple hundred thousand and a million—or roughly 1,000 pounds of live wormflesh under your feet. We all know that they break down the organic matter in the soil and aerate the earth, but they do more than that. They’re the lifeblood of the soil, in that they transport everything through it. When crop death occurs due to some fungus or bacteria, and scientists find a bacteria that fights the harmful bacteria, they release it into the soil by coating earthworms with it. The worms take it through an entire farm, or park, or forest, the way blood transports white blood cells.
They’re also responsible for what we know of the past. Charles Darwin once wrote, “Archaeologists are probably not aware how much they owe to worms for the preservation of many ancient objects. Coins, gold ornaments, stone implements, etc, if dropped on the surface of the ground, will infallibly be buried by the castings of worms in a few years, and will thus be safely preserved.” What we know of our ancestry, we know at least partly to worms. And when we dig back down through the soil, removing layer after layer, we’re digging through the work of generations earthworms which have preserved our past.