Scientists tap symbiotic lichens as sentinels of air quality, and now, climate problems
Ecologist Linda Geiser works her way through thick undergrowth on the steep hills of the Bull Run Watershed just outside of Portland, Ore. Every step in her heavy boots is deliberate. It would be easy to break an ankle here, or worse. A dense sea of ferns and berry bushes hides deep pits and sharp fallen branches.
This treacherous slope is a U.S. Forest Service field site, one of many in the United States, recognizable by its bright orange flagging fluttering from the trees. Geiser has patrolled terrain like this for 30 years. As manager of the Forest Service’s air-quality program, she’s tasked with monitoring pollution. So she has come here, not to check sophisticated equipment, but to find lichens.
Fringed and fuzzy, or as slick as a coat of paint, lichens are mosaics of fungi partnered with algae or cyanobacteria that speckle tree bark and dangle from the canopy (