Volcanoes are geological blowtorches. They incinerate everything, sterilize landscapes, and leave behind what looks like the surface of a dead planet. Then something weird happens.
Within months—sometimes weeks—life shows up. Not just any life, but these scrappy, microscopic colonizers that look at a field of cooling lava and think, “Yeah, I can work with this.” The first arrivals aren’t the charismatic mosses or ferns you might expect. They’re cyanobacteria and algae, organisms so primitive they make your average houseplant look like a technological marvel.
When Lava Fields Become Real Estate for the Desperate
Here’s the thing about fresh lava: it’s about as hospitable as a blast furnace. No water. No organic matter. pH levels that would make a chemistry teacher weep. Yet in 1959, when Kilauea erupted and buried 10 square kilometers of Hawaii under fresh basalt, scientists started finding cyanobacteria within six months. Six months! These organisms were setting up shop on rock that had been liquid less than a year earlier.
The pioneer species—mostly cyanobacteria like Fischerella and various species of algae—don’t need soil. They need moisture from fog or rain, some carbon dioxide, and honestly not much else. They’re essentially living off air and optimism. What they do next is genuinely clever: they secrete acids that start dissolving the rock beneath them, creating the first microscopic pockets of what will eventually become soil. It’s vandalism in the service of creation.
The Lichen Situation Nobody Asked For But Everyone Needs
Wait—maybe we’re thinking about this wrong.
Lichens show up next, and they’re not even technically one organism. They’re a fungus and an alga or cyanobacterium living in what biologists politely call a “symbiotic relationship” but which looks more like a permanent roommate situation. The fungus provides structure and water retention; the photosynthetic partner provides food. Together, they can survive on bare rock for decades, slowly expanding outward at rates that make glaciers look speedy. On the 1783 Laki lava flows in Iceland, lichens didn’t achieve significant coverage until about 50 years post-eruption. That’s commitment.
These organisms are remarkably picky about their real estate, though. Studies on Mount St. Helens after its 1980 eruption found that lichen colonization patterns depended heavily on rock texture, moisture availability, and whether the surface faced north or south. South-facing slopes dried out too quickly; north-facing ones retained moisture and got colonized faster. Turns out even microscopic pioneers have preferences.
Mosses That Treat Apocalypse Like a Minor Inconvenience
Mosses arrive once there’s enough organic matter—dead bacteria, decomposed algae, atmospheric dust—to create a thin veneer of proto-soil. They’re more sophisticated than their predecessors, with actual structures resembling roots and leaves, though botanists get testy if you call them that. On Hawaii’s younger lava flows, particularly those from the Pu’u ‘O’o eruption that started in 1983, mosses like Campylopus appeared within two to three years on aa lava (the chunky, rough kind) but took longer on pahoehoe (the smooth, ropy variety).
The aa versus pahoehoe distinction matters more than you’d think. Aa lava, despite looking like someone dumped a truckload of volcanic clinkers, actually provides better surfaces for colonization. All those cracks and crevices trap moisture and organic debris. Pahoehoe, smooth and photogenic, sheds water and offers fewer footholds. Life, it seems, prefers texture over aesthetics.
Ferns That Show Up Fashionably Late But Make an Entrance
Ferns are the dramatic arrivals of primary succession. They wait until there’s actual soil—maybe 5 to 10 millimeters of it—before making their entrance. On Surtsey, the volcanic island that erupted off Iceland’s coast in 1963, scientists documented every single species arrival. Mosses showed up in the first decade. Ferns took 30 years. That’s because fern spores, while abundant and capable of traveling hundreds of kilometers on wind currents, need more resources to germinate and establish.
The first fern on Surtsey was Cystopteris fragilis, the brittle bladder fern, discovered in 2008. By then, the island had accumulated enough bird guano, decomposed moss, and windblown organic matter to support something with actual fronds. Ferns accelerate soil formation dramatically because they produce substantial biomass annually—leaves that die, decompose, and add organic carbon to the developing soil.
The Timeline Nobody Wants to Hear About Because It’s Depressingly Slow
Primary succession on lava flows operates on geological time scales that make human patience look like a joke. The Hawaiian volcanoes offer a natural laboratory because you can compare flows of different ages. Flows less than 10 years old: mostly barren with scattered bacterial mats. Flows 50-100 years old: decent lichen and moss coverage, maybe some pioneering ferns. Flows 500-1000 years old: actual shrubs and small trees like Metrosideros polymorpha, the ohia lehua.
Full forest recovery? Try 20,000 to 1.4 milion years, depending on rainfall, elevation, and how much volcanic ash keeps falling on your developing ecosystem.
But those initial colonizers—those cyanobacteria and algae arriving on fresh lava while it’s still radiating heat—they’re performing a kind of biological alchemy. Taking nothing and turning it into something. Taking sterile rock and initiating a process that will eventually, given enough millennia, produce rainforest. That’s about as dramatic as it gets in ecology, even if nobody’s handing out awards for slowest transformation of planetary surface into livable habitat.
