scholarly journals Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ning Zong ◽  
Jing Jiang ◽  
Peili Shi ◽  
Minghua Song ◽  
Zhenxi Shen ◽  
...  
Keyword(s):  
Nutrient Enrichment ◽  
Alpine Meadow ◽  
Microbial Respiration ◽  
Climatic Factors ◽  
Distribution Patterns ◽  
The Tibetan Plateau ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
Nutrient Additions ◽  
Ecosystem Carbon

Quantifying the effects of nutrient additions on soil microbial respiration (Rm) and its contribution to soil respiration (Rs) are of great importance for accurate assessment ecosystem carbon (C) flux. Nitrogen (N) addition either alone (coded as LN and HN) or in combination with phosphorus (P) (coded as LN + P and HN + P) were manipulated in a semiarid alpine meadow on the Tibetan Plateau since 2008. Either LN or HN did not affectRm, while LN + P enhancedRmduring peak growing periods, but HN + P did not affectRm. Nutrient addition also significantly affectedRm/Rs, and the correlations ofRm/Rswith climatic factors varied with years. Soil water content (Sw) was the main factor controlling the variations ofRm/Rs. During the years with large rainfall variations,Rm/Rswas negatively correlated with Sw, while, in years with even rainfall,Rm/Rswas positively correlated with Sw. Meanwhile, in N + P treatments the controlling effects of climatic factors onRm/Rswere more significant than those in CK. Our results indicate that the sensitivity of soil microbes to climatic factors is regulated by nutrient enrichment. The divergent effects of Sw onRm/Rssuggest that precipitation distribution patterns are key factors controlling soil microbial activities and ecosystem C fluxes in semiarid alpine meadow ecosystems.

Effects of nitrogen additions on soil microbial respiration and its temperature sensitivity in a Tibetan alpine meadow

2018 ◽  
Vol 38 (7) ◽  
Author(s):  
叶成龙 YE Chenglong ◽  
张浩 ZHANG Hao ◽  
周小龙 ZHOU Xiaolong ◽  
周显辉 ZHOU Xianhui ◽  
郭辉 GUO Hui ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Alpine Meadow ◽  
Microbial Respiration ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
Nitrogen Additions

scholarly journals Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes

2017 ◽  
Vol 14 (17) ◽  
pp. 3947-3956 ◽  
Author(s):  
Bing Song ◽  
Jian Sun ◽  
Qingping Zhou ◽  
Ning Zong ◽  
Linghao Li ◽  
...  
Keyword(s):  
Alpine Meadow ◽  
Microbial Respiration ◽  
Ecosystem Respiration ◽  
C Sequestration ◽  
N Deposition ◽  
N Saturation ◽  
N Addition ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
Plant Respiration

Abstract. Increases in nitrogen (N) deposition can greatly stimulate ecosystem net carbon (C) sequestration through positive N-induced effects on plant productivity. However, how net ecosystem CO2 exchange (NEE) and its components respond to different N addition rates remains unclear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m−2 yr−1) in an alpine meadow on the Qinghai–Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an N addition gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment but shifted to N saturation responses in the second year with the highest NEE (−7.77 ± 0.48 µmol m−2 s−1) occurring under an N addition rate of 8 gN m−2 yr−1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to an N-induced saturation response of aboveground plant respiration and decreasing soil microbial respiration along the N addition gradient, while decreases in soil microbial respiration under high N addition were caused by N-induced reductions in soil pH. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. These results reveal temporal dynamics of N impacts and the rapid shift in ecosystem C fluxes from N limitation to N saturation. Our findings bring evidence of short-term initial shifts in responses of ecosystem C fluxes to increases in N deposition, which should be considered when predicting long-term changes in ecosystem net C sequestration.

scholarly journals Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes

2016 ◽  
Author(s):  
Bing Song ◽  
Jian Sun ◽  
Qingping Zhou ◽  
Ning Zong ◽  
Shuli Niu
Keyword(s):  
Alpine Meadow ◽  
Microbial Respiration ◽  
C Sequestration ◽  
N Deposition ◽  
N Saturation ◽  
N Addition ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
C Cycle ◽  
Plant Respiration

Abstract. The rising nitrogen (N) deposition could increase ecosystem net carbon (C) sequestration by stimulating plant productivity. However, how net ecosystem CO2 exchange (NEE) and its components respond dynamically to rising N deposition is far from clear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m−2 year−1) in an alpine meadow on the Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an increasing N loading gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment, but shifted to N saturation responses in the second year with the highest NEE (−7.77 ± 0.48 µmol m−2 s−1) occurring under N addition rate of 8 gN m−2 year−1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth, under high N addition. The saturation response of ER was mainly due to decreases in aboveground plant respiration and soil microbial respiration under high N addition, while the N-induced reduction in soil pH caused declines in soil microbial respiration. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. The results reveal temporal dynamics of N impacts and the rapid shift of ecosystem C cycle from N limitation to N saturation. These findings are helpful for better understanding and model projection of future terrestrial C sequestration under rising N deposition.

scholarly journals Dust-related impacts of mining operations on rangeland vegetation and soil: a case study in Yazd province, Iran

2021 ◽  
Author(s):  
Shahab IbrahimPour ◽  
Alireza KhavaninZadeh ◽  
Ruhollah Taghizadeh mehrjardi ◽  
Hans De Boeck ◽  
Alvina Gul
Keyword(s):  
Seed Germination ◽  
Vegetation Cover ◽  
Microbial Respiration ◽  
Germination Rate ◽  
Windward Side ◽  
Leeward Side ◽  
Mining Operations ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
The Impact

Abstract Destructive mining operations are affecting large areas of natural ecosystems, especially in arid lands. The present study aims at investigating the impact of iron mine exploitation on vegetation and soil in Nodoushan (Yazd province, central Iran). Based on the dominant wind, topography, slope, vegetation and soil of the area, soil and vegetation parameters close to ​the mine were recorded and analyzed according to the distance from the mine. In order to obtain the vegetation cover, a transect and plot on the windward and leeward side of the mine, with 100 m intervals and three replicates at each sampling location was used, yielding 96 soil samples. The amount of dust on the vegetation, the seed weight and seed germination rate of Artemisia sp. as the dominant species within the area, and the soil microbial respiration were measured. The relationship between vegetation cover and distance from the mine was not linear, which was due to an interplay between pollution from the mine and local grazing, while other factors did increase or decrease linearly. The results showed that, as the distance from the mine increased, the weight of 1000 seeds of Artemisia sp. was significantly increased from 271 to 494 mg and seed germination rate and soil microbial respiration were significantly increased from 11.7 to 48.4 % and from 4.5 to 5.9 mg CO2 g− 1 soil day− 1 respectively, while the amount of dust significantly decreased from 43.5 to 6 mg (g plant)−1 between the distance of 100 to 600 m from the mine in the leeward direction. A similar trend was observed in the windward side, though negative effects were lower compared to the same distance along the leeward sample locations. The direct and indirect effects on plant growth and health from mining impacts generally decreased linearly with increasing distance from the mine, up to at least 600 m. Our study serves as a showcase for the potential of bio-indicators as a cost-effective method for assessing impacts of mining activities on the surrounding environment.

scholarly journals Soil microbial respiration in arctic soil does not acclimate to temperature

2008 ◽  
Vol 11 (10) ◽  
pp. 1092-1100 ◽  
Author(s):  
Iain P. Hartley ◽  
David W. Hopkins ◽  
Mark H. Garnett ◽  
Martin Sommerkorn ◽  
Philip A. Wookey
Keyword(s):  
Microbial Respiration ◽  
Soil Microbial ◽  
Soil Microbial Respiration ◽  
Arctic Soil
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