Impacts of nitrogen deposition on carbon and nitrogen cycling in alpine Racomitrium heath in the UK and prospects for recovery
| Autor: | Rachel Helliwell, Andrea J. Britton, Sheila Gibbs, J. M. Fisher |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010504 meteorology & atmospheric sciences
Reactive nitrogen Nitrogen Health Toxicology and Mutagenesis Bryophyta 010501 environmental sciences Toxicology Graminoid 01 natural sciences Carbon Cycle Soil Nutrient Air Pollution Ecosystem Nitrogen cycle 0105 earth and related environmental sciences General Medicine Nitrogen Cycle Pollution Bryopsida Carbon United Kingdom Environmental chemistry Soil water Environmental science Terrestrial ecosystem Water quality Environmental Monitoring |
| Zdroj: | Environmental Pollution. 254:112986 |
| ISSN: | 0269-7491 |
| DOI: | 10.1016/j.envpol.2019.112986 |
| Popis: | Deposition of reactive nitrogen (N) is a major threat to terrestrial ecosystems associated with impacts on ecosystem properties and functions including carbon (C) and nutrient stocks, soil water quality and nutrient retention. In the oceanic-alpine Racomitrium heath habitat, N deposition is associated with moss mat degradation and a shift from bryophyte to graminoid dominance. To investigate the effects of moss mat decline on C and N stocks and fluxes, we collected Racomitrium heath vegetation/soil cores from sites along a gradient of N deposition in the UK. Cores were maintained under controlled conditions and exposed to scenarios of current (8–40 kg N ha−1 y−1), reduced (8 kg N ha−1 y−1) and elevated (50 kg N ha−1 y−1) N deposition. Cores from high N deposition sites had smaller aboveground C and N stocks and, under current conditions, leached large amounts of inorganic N and had low soil water pH compared with low N deposition sites. With reduced N deposition there was evidence for rapid recovery of soil water quality in terms of reduced N leaching and small increases in pH. Under high N deposition, cores from low N deposition sites retained much of the applied N while those with a history of high N deposition leached large amounts of inorganic N. Carbon fluxes in soil water and net CO2 fluxes varied according to core source site but were not affected by the N deposition scenarios. We conclude that C and N stocks and cycling in Racomitrium heath are strongly affected by long-term exposure to N deposition but that soil water quality may improve rapidly, if N deposition rates are reduced. The legacy of N deposition impacts on moss mat cover and vegetation composition however, mean that the ecosystem remains sensitive to future pulses in N input. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect