Lichenized fungi, a primary bioindicator/biomonitor for bio-mitigation of excessive ambient air nitrogen deposition worldwide

Abstract

Nitrogen pollution is one of the most critical factors that has become a threat to the subsistence of life on earth. The increasing use of nitrogen fertilizers had made technological interventions of little use in its mitigation. Biomonitors such as lichens can be a sustainable tool for accessing the effects of nitrogen eutrophication in the ambient environment at very early stages. Lichens can tolerate higher concentrations of nitrogen through metabolic adaptations and community change dynamics. The higher nitrogen deposition of nitrogen in the ambient environment is reflected in the change in lichen community composition, ecophysiology, stable nitrogen isotope ratio, and biochemistry. The changes induced in lichens against nitrogen pollution are being used for bioindicator and/or biomonitoring purposes worldwide. The nitrogen bioaccumulation in lichens has also helped assess the critical nitrogen loads for native vegetation and in the habitats with dominant growth, also acts as a sink for deposited nitrogen. The current chapter hereby reviews the normal assimilation of nitrogen in lichens, the mechanisms of excessive nitrogen tolerance, the effect on the fauna dependent on them as food, and the various parameters that make them one of the most appropriate indicators of excessive ambient air nitrogen deposition worldwide. © 2022 Elsevier Inc. All rights reserved.