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Cation ratios in Cladonia portentosa as indices of precipitation acidity in the British Isles
Author(s) -
HYVÄRINEN M.,
CRITTENDEN P. D.
Publication year - 1996
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1996.tb01872.x
Subject(s) - lichen , topsoil , precipitation , acid rain , chemistry , deposition (geology) , environmental chemistry , magnesium , soil ph , botany , soil water , ecology , biology , sediment , paleontology , physics , organic chemistry , meteorology
summary The relationship between rainfall chemistry and the concentrations of potassium, calcium and magnesium in the apices (top 5 mm) of the cushion‐forming; lichen Cladonia portentosa (Dufour) Coem was investigated. Lichen samples, together with underlying topsoil, were collected from heathlands in close proximity to rain gauges in the UK Acid Deposition Monitoring Network, located in rural areas of the British Isles, which provide wet deposition data based on weekly bulk samples. The ratios K + : Mg 2+ and extracellular Mg 2+ : intracellular Mg 2+ in the lichen apices were strongly correlated with H + concentration in precipitation. It is suggested that shifts in these ratios occur owing to enhanced displacement of extracellular Mg 2+ by elevated H + concentration in acid rain. By contrast, there was no indication of any relationship between total acid deposition and lichen chemistry. The concentration of Mg 2+ in the lichen was weakly correlated with that in soil, whereas lichen Ca 2+ content was not correlated with either precipitation or soil chemistry. It is concluded that these ratios describing changes in lichen Mg 2+ content provide good biomarkers for wet‐deposited acidity.