在大气CO浓度升高的情况下，经过两个生长季节后，完整草地单块土样中受刺激的一氧化氮通量。

Stimulated NO flux from intact grassland monoliths after two growing seasons under elevated atmospheric CO.

作者信息

Arnone Iii John A, Bohlen Patrick J

机构信息

Department of Integrative Biology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland e-mail:

Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545, USA, , , , , , US.

出版信息

Oecologia. 1998 Sep;116(3):331-335. doi: 10.1007/s004420050594.

DOI:10.1007/s004420050594

PMID:28308063

Abstract

Long-term exposure of native vegetation to elevated atmospheric CO concentrations is expected to increase C inputs to the soil and, in ecosystems with seasonally dry periods, to increase soil moisture. We tested the hypothesis that these indirect effects of elevated CO (600 μl l vs 350 μl l) would improve conditions for microbial activity and stimulate emissions of nitrous oxide (NO), a very potent and long-lived greenhouse gas. After two growing seasons, the mean NO efflux from monoliths of calcareous grassland maintained at elevated CO was twice as high as that measured from monoliths maintained at current ambient CO (70 ± 9 vs 37 ± 4 μg NO m h in October, 27 ± 5 vs 13 ± 3 μg NO m h in November after aboveground harvest). The higher NO emission rates at elevated CO were associated with increases in soil moisture, soil heterotrophic respiration, and plant biomass production, but appear to be mainly attributable to higher soil moisture. Our results suggest that rising atmospheric CO may contribute more to the total greenhouse effect than is currently estimated because of its plant-mediated effects on soil processes which may ultimately lead to increased NO emissions from native grasslands.

摘要

预计本地植被长期暴露于大气中二氧化碳浓度升高的环境下，土壤中的碳输入会增加，而在有季节性干旱期的生态系统中，土壤湿度也会增加。我们检验了这样一个假设：二氧化碳浓度升高（600 μl l相较于350 μl l）产生的这些间接影响会改善微生物活动条件，并刺激一氧化二氮（N₂O，一种极具效力且寿命长的温室气体）的排放。经过两个生长季，维持在高二氧化碳浓度下的石灰性草原原状土柱的平均N₂O通量是维持在当前环境二氧化碳浓度下原状土柱的两倍（10月为70±9 μg N₂O m⁻² h⁻¹ 相较于37±4 μg N₂O m⁻² h⁻¹，地上部分收割后的11月为27±5 μg N₂O m⁻² h⁻¹ 相较于13±3 μg N₂O m⁻² h⁻¹）。高二氧化碳浓度下较高的N₂O排放率与土壤湿度增加、土壤异养呼吸以及植物生物量生产的增加有关，但似乎主要归因于较高的土壤湿度。我们的结果表明，大气中二氧化碳浓度上升对温室效应总量的贡献可能比目前估计的要大，因为其通过植物对土壤过程产生影响，最终可能导致原生草原N₂O排放增加。