Does the lichen mat alleviate the effects of wet deposited nickel on soil microorganisms and Scots pine (Pinus sylvestris L.) seedlings?

• Published in: Plant and soil 2001-03, Vol.230 (2), p.267-277
• Main Authors: Roitto, Marja, Strömmer, Rauni, Ahonen-Jonnarth, Ulla, Hyvärinen, Marko, Markkola, Anna Mari
• Format: Article
• Language: English
• Subjects: Acid soils; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Distilled water; Ecotoxicology, biological effects of pollution; Evergreen trees; Forest soils; Fundamental and applied biological sciences. Psychology; Growing season; Heavy metals; lichen; Lichens; Microorganisms; Nickel; Non agrochemicals pollutants; Organic soils; Phytopathology. Animal pests. Plant and forest protection; Pine needles; Pine trees; Pinus sylvestris; Plants; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; seedling; Seedlings; soil microorganism; Soil microorganisms; Soil pollution; Terrestrial environment, soil, air; wet deposition
• ISSN: 0032-079X; 1573-5036; 1573-5036
• DOI: 10.1023/A:1010341715997

A field experiment was conducted in a dry heath forest dominated by Scots pine (Pinus sylvestris L.) and a matforming lichen (Cladina stellaris (Opiz) Brodo) to assess the effect of wet-deposited nickel (Ni) on pine seedlings and soil microorganisms, and to explore whether an intact lichen mat could act as a buffer against heavy metal deposits. Pine seedlings were planted in quadrats covered by a natural lichen layer and in quadrats from which the lichen layer had been completely removed. The quadrats were exposed to four levels of Ni deposition: 0 (i.e., distilled water), 10, 100 and 1000 mg m⁻² year⁻¹ in two growing seasons. Increasing Ni deposition led to an increase in the Ni content of the needles, roots and the soil organic layer. The lichen mat reduced Ni flow to the organic soil layer, but had no significant, reducing effect on needle or root Ni concentration. The most severe Ni treatment had detrimental effects on seedling growth and increased peroxidase activity in the previous years needles. Removal of the lichen layer did not increase susceptibility of seedlings to Ni. Values of maximal carbon use efficiency (Max) and metabolic quotient (qCO₂) of the soil microorganisms indicated protective value of the lichen mat to soil microorganisms at the highest Ni treatment. Skimming per se decreased basal respiration, qCO₂ and concentrations of potassium in the soil and also increased the lag period of the microorganisms as a response to in situ substrate addition.