| Studies were done around a coal-fired power plant, comparing sites 9 and 12 and 21 km away from the plant with a control site 42 km away. Chlorophyll analyses showed a fertilizing effect on surrounding cyanobacterial-lichen crusts at sites nearer the plant when compared to the control site. Less pH-buffered rock lichens, however, had significantly increased chlorophyll degradation and increased electrolyte leakage at the nearer sites. Nitrogenase activity in a crustal soil lichen was depressed at the nearer sites as well. Analyses of soluble sulfates in soils were the same between sites, but analyses of sulfur in the cyanobacterial filaments showed increased levels near the plant, indicating that ground fumigations were taking place at the nearer sites.;When exposed to power plant effluents, the degree of contact with the pH-buffering substrate was important: cyanobacteria, embedded in soils that buffered acidity, may use nitrates and sulfates as fertilizers. Rock and soil lichens, with less contact and less buffering, showed opposite effects. |
