Effects of long-term elevated [CO2] from natural CO2 springs on Nardus stricta: photosynthesis, biochemistry, growth and phenology |
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Authors: | A C Cook D T Tissue S W Roberts & W C Oechel |
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Institution: | Global Change Research Group, Department of Biology, San Diego State University, San Diego, CA 92182 USA, ,;Department of Biology, Texas Tech University, Lubbock, TX 79409 USA and,;Data Design Group, La Jolla, CA 92037 USA |
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Abstract: | Plants of Nardus stricta growing near a cold, naturally emitting CO2 spring in Iceland were used to investigate the long-term (> 100 years) effects of elevated CO2] on photosynthesis, biochemistry, growth and phenology in a northern grassland ecosystem. Comparisons were made between plants growing in an atmosphere naturally enriched with CO2 (≈ 790 μ mol mol–1) near the CO2 spring and plants of the same species growing in adjacent areas exposed to ambient CO2 concentrations (≈360 μ mol mol–1). Nardus stricta growing near the spring exhibited earlier senescence and reductions in photosynthetic capacity (≈25%), Rubisco content (≈26%), Rubisco activity (≈40%), Rubisco activation state (≈23%), chlorophyll content (≈33%) and leaf area index (≈22%) compared with plants growing away from the spring. The potential positive effects of elevated CO2] on grassland ecosystems in Iceland are likely to be reduced by strong down-regulation in the photosynthetic apparatus of the abundant N. stricta species. |
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Keywords: | Nardus stricta Arctic biochemistry CO2 springs elevated CO2 global climate change growth natural vegetation Iceland photosynthesis phenology |
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