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Isotopic evidence for increased carbon and nitrogen exchanges between peatland plants and their symbiotic microbes with rising atmospheric CO 2 concentrations since 15,000 cal. year BP.
- Source :
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Global change biology [Glob Chang Biol] 2023 Apr; Vol. 29 (7), pp. 1939-1950. Date of Electronic Publication: 2023 Jan 13. - Publication Year :
- 2023
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Abstract
- Whether nitrogen (N) availability will limit plant growth and removal of atmospheric CO <subscript>2</subscript> by the terrestrial biosphere this century is controversial. Studies have suggested that N could progressively limit plant growth, as trees and soils accumulate N in slowly cycling biomass pools in response to increases in carbon sequestration. However, a question remains over whether longer-term (decadal to century) feedbacks between climate, CO <subscript>2</subscript> and plant N uptake could emerge to reduce ecosystem-level N limitations. The symbioses between plants and microbes can help plants to acquire N from the soil or from the atmosphere via biological N <subscript>2</subscript> fixation-the pathway through which N can be rapidly brought into ecosystems and thereby partially or completely alleviate N limitation on plant productivity. Here we present measurements of plant N isotope composition (δ <superscript>15</superscript> N) in a peat core that dates to 15,000 cal. year BP to ascertain ecosystem-level N cycling responses to rising atmospheric CO <subscript>2</subscript> concentrations. We find that pre-industrial increases in global atmospheric CO <subscript>2</subscript> concentrations corresponded with a decrease in the δ <superscript>15</superscript> N of both Sphagnum moss and Ericaceae when constrained for climatic factors. A modern experiment demonstrates that the δ <superscript>15</superscript> N of Sphagnum decreases with increasing N <subscript>2</subscript> -fixation rates. These findings suggest that plant-microbe symbioses that facilitate N acquisition are, over the long term, enhanced under rising atmospheric CO <subscript>2</subscript> concentrations, highlighting an ecosystem-level feedback mechanism whereby N constraints on terrestrial carbon storage can be overcome.<br /> (© 2022 John Wiley & Sons Ltd.)
Details
- Language :
- English
- ISSN :
- 1365-2486
- Volume :
- 29
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Global change biology
- Publication Type :
- Academic Journal
- Accession number :
- 36585918
- Full Text :
- https://doi.org/10.1111/gcb.16578