Life at 10x and Beyond
Lichens, Liverworts, a Microscope & Me
A Post from the Past: Introduction
I wrote the following essay 15 years ago after taking a course on lichens at the Chicago Botanic Garden.
Ubiquitous and unobtrusive, lichens are composite organisms, “holobionts” consisting of a fungus paired most often with algae or sometimes cyanobacteria, with yeast in the mix as well. They have been on Earth for the last quarter billion years and no doubt will survive any human-mediated climate chaos that comes their way.
Lichens have seen it all. Whatever this planet throws at them (or, in the case of an asteroid, whatever is thrown at the planet), lichens survive. It may take some species a million years to adapt, but in lichen time, that’s almost speedy.
They check all the boxes of The 7 Characteristics of Better Answers:
Small
Modular
Flexible
Adaptable
Scalable
Cheap at the unit cost
Riffable
Our prospects without lichens are less certain.
“…Losing lichens would be disastrous for the countless ecosystems that rely on them. In waterlogged environments, such as the temperate rain forests of the Pacific Northwest, lichens are key cogs in the hydrology process because they absorb water as it moves through the forest system. In deserts, a crust of lichens stabilizes soil and thus helps prevent erosion. Lichens even keep the carbon cycle humming: as their algae photosynthesize, they pull carbon dioxide from the air and pump out oxygen. After they die, their carbon-rich bodies decompose…” — “Lichens Could Need More Than a Million Years to Adapt to Climate Change,” Scientific American
A world made safer for lichens is also be a world made safer for us. It is a world with a resilient future.
from July 2008
It was bound to happen. The only wonder was it hadn’t happened sooner. Someone finally sat me down in front of a microscope and said, “Look!”
And what I saw was a “British Soldier” (Cladonia cristatella), a wee little thing with a bright red cap, its “fruiting body.” I studied its extravagant folds and improbably lurid top, which is smaller than the head of a pin. The next few hours were lost in Lilliputian delight.
Little had I known that I had been waiting all my life to take the “Lichens All Around Us!” class at the Chicago Botanic Garden. The teacher patiently explained the basics of key guide identification, starting with the broad, shape-based categories. Foliose. Crustose. Fruticose. Looks leafy. Looks crusty. Looks shrubby. Got it.
After that, it was alien territory, full of new words for previously unimagined things. Soredia. Thallus. Xanthomendoza. Physcia. Candellaria. Squamule. Apothecia. Podetia. I was a stranger in a strange land.
•••••••••••••
When I travel, I like to go for walk to get a sense of things before anyone has a chance to tell me where I am. Within minutes of stashing my bags at a hotel in Bologna, I am wandering the narrow side streets radiating off the main square. There are bookstores—so many bookstores—gelato shops, bakeries, one notably saucy fountain, a few tucked-away churches and some fabulous street theater.
In Havana, where I scouted a segment on the Old Havana neighborhood for a National Geographic series, I am strolling along El Malecon between sea and skyline when a loud honk from a meticulously maintained 1950s Buick with question-mark brakes warns me to safety. Everything is more vivid when nothing is yet familiar.
Traveling to the land of lichens has been every micron as interesting and surprising, beginning with the beginning: a wrong turn and a touch of serendipity.
This past spring, groves of tiny Seussian palm trees took over an old strawberry pot I use to grow moss roses. I put off planting for weeks. I was sure they were lichens and wanted to know more, so signed up for a class.
Alas, my would-be lichen turned out to be liverwort—Marchantia polymorpha—but no matter. Liverworts, which are spore-producing plants related to ferns, mosses and horsetails, are plenty wonderful, but now I was completely besotted with these strange little lichen plants, enthralled by the symbiotic society of fungi, algae and the occasional cyanobacterium (a microbe with a talent for photosynthesis).
Lichens are partnerships. An estimated 13,500 species of fungi seek out and encapsulate a handful of algal species and cyanobacteria in order to harvest the sugars they produce for food. In exchange, algae and cyanobacteria, now protected by water-retaining fungal armor, are given the opportunity to travel across dry land and conquer the world. These odd-couples can make a go of it just about anywhere. There are lichens on rocks in the Arctic that live for hundreds, even thousands of years. In fact, crustose lichens, the ones that grow on rocks, are literally at one with their rocks. The line between inorganic and organic can be vanishingly thin.
Split apart a lichen’s fungus and algae (or cyanobacteria) and the fungus starves. Provide there is enough moisture and conditions are right, the algae (or cyanobacteria) survive.
This is basically the same story for humans and our “good” microbes. If we were to lose the gut bugs that not only help keep “bad” microbes at bay, but also produce nutrients such as Vitamin K, we would be in trouble. Microbiomes on skin, on teeth and in all sorts of surprising places play equally key roles in maintaining our health.
This is true for bees, birds, alligators, cows, fish, puppies and pretty much every living thing: Animals and plants need their microbes, but the microbes don’t always need their animals or plants. Once you begin to understand life as a series of mutually beneficial alliances, it gets a little easier to accept the role as the “fungal half.”
Biologist Lynn Margulis’ career has been dedicated to working out the intricate relationships that define our world. Her work with James Lovelock led to the Gaia hypothesis that described how life, though a complex series of self-regulating feedback loops, generates conditions for life. With essayist Dorian Sagan, she has written extensively about Nature’s propensity for partnership. From the cosmic to the genomic, symbiosis rules at every scale. (Symbiotic Planet, Acquiring Genomes).
It was time for a class field trip. On our way to a patch of forest, we walked through a parking lot, 10x loupes and magnifying glasses in hand. There were lichens everywhere. Their were colonies—whole worlds—thriving on concrete curbs. It was a rainy morning, which puffed up the lichens’ algae and made their colors more intense. How had I gone a lifetime without seeing what was right there to be seen?
We went through the classification guide: Was a lichen foliose or crustose? Was it easy to peel off the substrate surface? Was it greenish or yellow? What color was its underside? Did it have apothecia (cups full of spore-filled sacs) or soredia (fringes of fungal/algal cells ready to blow away and reproduce)?
We identified 29 species in three hours. We learned that Anisomeridium polypori gives white oak its white bark. We found a lichen with wiry black fringe, Phaeocalicium polyporaeum, growing on a “turkey tail” fungus (Trichaptum biforme). In the realm of the alien, this one stood out. Its fruiting body was readily apparent, but the exact location of its body body is still something of a mystery.
After class, I spent another hour and a half wandering around the garden alone, taking closer looks at wooden benches and cement walls. I marveled at “LBM’s” (little brown mushrooms) on a lichen-covered linden tree. Through a 10x loupe, mosses appeared giant. I followed the intrepid trekking of ants and spiders. There were dozens of species never mentioned on identification plaques. I was a giant Horton surrounded by whole bunch of Who’s.
The analogy turned out to be uncomfortably apt. Despite their ability to survive on the most forlorn surfaces in the harshest of climates, and despite their seeming irrepressibility some lichens are, in fact, repressible. In the presence of various chemical pollutants, some species die off, making lichens easy-to-monitor, reliable indicators of environmental health.
But it goes even deeper than that. Dozens of bird and small mammal species seek out lichens to line their nests and burrows, possibly as a defense against disease and parasites. There are hundreds of active compounds in lichens, some of have antibiotic properties. Usnea, for example, is a staple of Chinese and homeopathic remedies.
Reindeer famously live on a diet of lichens. Lose the lichens and Santa has to find alternate transportation.
Back in the lab on the last day of class, we were finally ready for the 100x microscopes, the ones designed to reveal the daintiest of details. I was given a note card onto which a few chips from a picnic table had been glued back in 1992. I carefully squirted a drop of water on some round black bumps that were supposed to be the fruiting bodies of Amadina (nee Buella puntata). Once the bumps were properly plumped up, I was able to scrape them onto a glass slide, ready for the microscope.
Another drop of water. A slide cover. A firm press to break open the fruiting bodies and there they were: translucent spore sacs, eight to a bunch, just as advertised. Amazing. Stunning. Perfect.
My lab-mate managed to find an actual individual spore. Sturdy cell walls. Distinct cell markings exactly where they were supposed to be. After years spent shriveled up, dried out and glued to a note card, this little lichen appeared ready to pick up the narrative.
I drove home that night with the windows rolled down, listening to cicadas and glancing at summer-sky stars. It seemed a given that life would be everywhere throughout the universe. Life on Mars? Lichens on Mars? Lichens from Mars?
I wouldn’t bet against them.
