Aridity and plant uptake interact to make dryland soils hotspots for nitric oxide (NO) emissions
| Autor: | James O. Sickman, Delores M. Lucero, Peter M. Homyak, Joseph C. Blankinship, Joshua P. Schimel, Kenneth Marchus |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
010504 meteorology & atmospheric sciences
NO pulses Nitric Oxide Poaceae 01 natural sciences complex mixtures Sink (geography) Grassland nitric oxide Dry season Soil Pollutants Ecosystem Water content 0105 earth and related environmental sciences chemodenitrification Abiotic component geography Air Pollutants drylands Multidisciplinary geography.geographical_feature_category fungi Humidity 04 agricultural and veterinary sciences Plants Arid Agronomy PNAS Plus N cycling Soil water 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Desert Climate |
| Zdroj: | Homyak, PM; Blankinship, JC; Marchus, K; Lucero, DM; Sickman, JO; & Schimel, JP. (2016). Aridity and plant uptake interact to make dryland soils hotspots for nitric oxide (NO) emissions. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 113(19), E2608-E2616. doi: 10.1073/pnas.1520496113. UC Riverside: Retrieved from: http://www.escholarship.org/uc/item/0xj6c45m Proceedings of the National Academy of Sciences of the United States of America, vol 113, iss 19 |
| DOI: | 10.1073/pnas.1520496113. |
| Popis: | Nitric oxide (NO) is an important trace gas and regulator of atmospheric photochemistry. Theory suggests moist soils optimize NO emissions, whereas wet or dry soils constrain them. In drylands, however, NO emissions can be greatest in dry soils and when dry soils are rewet. To understand how aridity and vegetation interact to generate this pattern, we measured NO fluxes in a California grassland, where we manipulated vegetation cover and the length of the dry season and measured [δ(15)-N]NO and [δ(18)-O]NO following rewetting with (15)N-labeled substrates. Plant N uptake reduced NO emissions by limiting N availability. In the absence of plants, soil N pools increased and NO emissions more than doubled. In dry soils, NO-producing substrates concentrated in hydrologically disconnected microsites. Upon rewetting, these concentrated N pools underwent rapid abiotic reaction, producing large NO pulses. Biological processes did not substantially contribute to the initial NO pulse but governed NO emissions within 24 h postwetting. Plants acted as an N sink, limiting NO emissions under optimal soil moisture. When soils were dry, however, the shutdown in plant N uptake, along with the activation of chemical mechanisms and the resuscitation of soil microbial processes upon rewetting, governed N loss. Aridity and vegetation interact to maintain a leaky N cycle during periods when plant N uptake is low, and hydrologically disconnected soils favor both microbial and abiotic NO-producing mechanisms. Under increasing rates of atmospheric N deposition and intensifying droughts, NO gas evasion may become an increasingly important pathway for ecosystem N loss in drylands. |
| Databáze: | OpenAIRE |
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