Nose-to-rock on the summit of Wheeler Mountain, just west of Lake Willoughby in Vermont’s Northeast Kingdom, I was attempting to unravel the microecology of granite ledges when I stumbled across a phenomenon I failed to understand.
I had been examining the great dome’s surface with a magnifier and close-up camera equipment. Tracking tiny mites, centipedes, ants, and beetles as they scurried across reflective quartz was my challenge. Rewards came in hard-won photographs of minute mountain inhabitants that most of us never see.
I also examined pioneering plant life. This was what made the rock face habitable, at least for those organisms capable of surviving harsh conditions ranging from searing summer heat to ice scour in the subzero temperatures of a northern winter.
The granite face of Wheeler Mountain revealed that weathering in the form of expansion from intense heat and contraction from equally intense cold - plus the effects of wind and water runoff or freezing in cracks - had a profound effect upon the rock. You could see flakes beginning to separate from the bare dome and find broken-off and pulverized flakes down-slope. At the bottom of the cliff were pockets of coarse quartz sand. All were related, having the same origin. Wheeler Mountain was revealing in minute detail how it was slowly eroding into the valley.
While examining the beginning of this process, where a flake had lifted slightly from ice expansion but not yet detached from the rock face, I noted a bit of color underneath. Using a powerful magnifier, I could see that the thin quartz flake was transparent, and clusters of green algal cells speckled the space between its “window” and the still-unaffected rock surface beneath, a sandwich separation of less than a millimeter.
I scraped off some cells and examined them with a powerful field microscope I carry with me. They looked familiar and resembled green algae commonly found in ponds, a “chlorella” type of cell.
In the 1970s, microbiologist Wolf Vishniac was studying microorganisms in Antarctica. He reported in the journal Science that photosynthetic life existed under the thin outer layer of snow-free rocks. The rock surface apparently served as a sheltering greenhouse, protecting against the severity of Antarctic conditions, but allowing sunlight to penetrate. It was an interesting finding that excited people about the possibility of life on Mars, but the topic wasn’t pursued after Vishniac’s experiment because the Mars Viking Lander was cancelled.
I thought the cells I found under the quartz flake might be a northern version of what Vishniac found in Antarctica. No reason why not: conditions on Wheeler Mountain create numerous examples of these tiny greenhouses. Since algal spores are always blowin’ in the wind, when they find a place where moisture is present and evaporation curtailed, where sunlight is plentiful, why not flourish under miniature greenhouse conditions?
But that didn’t satisfy my increasing curiosity.
Lichens, as every biology student knows, are not individual organisms, but two - an alga and a fungus - living together in close symbiotic harmony. In many cases, the fungi parasitize the algae, holding them securely within a microscopic jungle of filamentous hyphae, drawing nourishment while furnishing the little green cells with a protected place to live.
Lichenologists give each kind of lichen its own genus and species name, as though it were an individual organism. It’s also possible to identify the algal partner alone, since many of them live independently in pond and marsh. Lichen fungi aren’t so easily identified, however, because most of them don’t normally live separately from the lichen association, although biologists have successfully cultured several of them in labs.
A continuing question: How could this remarkable association have evolved in the distant past? All sorts of hypotheses have been floated, but we’ll never know.
Or will we?
Under those quartz flakes on the domes of Wheeler Mountain, I found something else. Close to the algae and sometimes intermingled with their cells were tiny, colorless, brush-like objects, clearly a form of life. Their abbreviated “parts” were the size of fungal hyphae, with the same minimal structure. Could what I saw be the beginning of a lichen association? Perhaps a fungus emerging from a spore and about to reach out to algal cells in a symbiotic embrace?
I managed to photograph the scene under a microscope, but studying pictures of the organisms didn’t help. So I mailed photos to the world’s two foremost lichenologists. Each replied thoughtfully and at length, saying they’d never seen anything like the apparent relationship shown in the photographs. They were interested, but baffled.
Disappointed and realizing I had little expertise in the field of lichenology, I went on with other studies. The mystery remains.