Microbial responses to carbon and nitrogen supplementation in an Antarctic dry valley soil

2012 ◽  
Vol 25 (1) ◽  
pp. 55-61 ◽  
Author(s):  
P.G. Dennis ◽  
A.D. Sparrow ◽  
E.G. Gregorich ◽  
P.M. Novis ◽  
B. Elberling ◽  
...  
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Microbial Community ◽  
Control Treatment ◽  
Dry Valleys ◽  
Carbon Addition ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Organic Carbon Concentration

AbstractThe soils of the McMurdo Dry Valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain active biological communities that contribute to the biogeochemical processes. We have used ester-linked fatty acid (ELFA) analysis to investigate the effects of additions of carbon and nitrogen in glucose and ammonium chloride, respectively, on the soil microbial community in a field experiment lasting three years in the Garwood Valley. In the control treatment, the total ELFA concentration was small by comparison with temperate soils, but very large when expressed relative to the soil organic carbon concentration, indicating efficient conversion of soil organic carbon into microbial biomass and rapid turnover of soil organic carbon. The ELFA concentrations increased significantly in response to carbon additions, indicating that carbon supply was the main constraint to microbial activity. The large ELFA concentrations relative to soil organic carbon and the increases in ELFA response to organic carbon addition are both interpreted as evidence for the soil microbial community containing organisms with efficient scavenging mechanisms for carbon. The diversity of the ELFA profiles declined in response to organic carbon addition, suggesting the responses were driven by a portion of the community increasing in dominance whilst others declined.

scholarly journals Elevated atmospheric CO2 impact on carbon and nitrogen transformations and microbial community in replicated wetland

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Dawei Jiang ◽  
Lifei Chen ◽  
Nan Xia ◽  
Eyram Norgbey ◽  
Desmond Ato Koomson ◽  
...  
Keyword(s):  
Microbial Community ◽  
Organic Carbon ◽  
Soil Microbial Community ◽  
Water Hyacinth ◽  
Total Carbon ◽  
Wetland Soil ◽  
Nitrogen Transformations ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Soil Pool

Abstract Background Elevated atmospheric CO2 has direct and indirect influences on ecosystem processes. The impact of elevated atmospheric CO2 concentration on carbon and nitrogen transformations, together with the microbial community, was evaluated with water hyacinth (Eichhornia crassipes) in an open-top chamber replicated wetland. The responses of nitrogen and carbon pools in water and wetland soil, and microbial community abundance were studied under ambient CO2 and elevated CO2 (ambient + 200 μL L−1). Results Total biomass for the whole plant under elevated CO2 increased by an average of 8% (p = 0.022). Wetlands, with water hyacinth, showed a significant increase in total carbon and total organic carbon in water by 7% (p = 0.001) and 21% (p = 0.001), respectively, under elevated CO2 compared to that of ambient CO2. Increase in dissolved carbon in water correlates with the presence of wetland plants since the water hyacinth can directly exchange CO2 from the atmosphere to water by the upper epidermis of leaves. Also, the enrichment CO2 showed an increase in total carbon and total organic carbon concentration in wetland soil by 3% (p = 0.344) and 6% (p = 0.008), respectively. The total nitrogen content in water increased by 26% (p = 0.0001), while total nitrogen in wetland soil pool under CO2 enrichment decreased by 9% (p = 0.011) due to increased soil microbial community abundance, extracted by phospholipid fatty acids, which was 25% larger in amount than that of the ambient treatment. Conclusion The study revealed that the elevated CO2 would affect the carbon and nitrogen transformations in wetland plant, water, and soil pool and increase soil microbial community abundance.

scholarly journals Altitude and Vegetation Affect Soil Organic Carbon, Basal Respiration and Microbial Biomass in Apennine Forest Soils

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 710
Author(s):  
Luisa Massaccesi ◽  
Mauro De Feudis ◽  
Angelo Leccese ◽  
Alberto Agnelli
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Forest Soils ◽  
Soil Microbial Community ◽  
Soil Microbial Biomass ◽  
Pine Forests ◽  
Soil Microbial ◽  
Ostrya Carpinifolia

Both altitude and vegetation are known to affect the amount and quality of soil organic matter (SOM) and the size and activity of soil microbial biomass. However, when altitude and vegetation changes are combined, it is still unclear which one has a greater effect on soil chemical and biochemical properties. With the aim of clarifying this, we tested the effect of altitude (and hence temperature) and vegetation (broadleaf vs pine forests) on soil organic carbon (SOC) and soil microbial biomass and its activity. Soil sampling was carried out in two adjacent toposequences ranging from 500 to 1000 m a.s.l. on a calcareous massif in central Italy: one covered only by Pinus nigra J.F. Arnold forests, while the other covered by Quercus pubescens Willd., Ostrya carpinifolia Scop. and Fagus sylvatica L. forests, at 500, 700 and 1000 m a.s.l., respectively. The content of SOC and water-extractable organic carbon (WEOC) increased with altitude for the pine forests, while for the broadleaf forests no trend along the slope occurred, and the highest SOC and WEOC contents were observed in the soil at 700 m under the Ostrya carpinifolia forest. With regard to the soil microbial community, although the size of the soil microbial biomass (Cmic) generally followed the SOC contents along the slope, both broadleaf and pine forest soils showed similar diminishing trends with altitude of soil respiration (ΣCO2-C), and ΣCO2-C:WEOC and ΣCO2-C:Cmic ratios. The results pointed out that, although under the pine forests’ altitude was effective in affecting WEOC and SOC contents, in the soils along the broadleaf forest toposequence this effect was absent, indicating a greater impact of vegetation than temperature on SOC amount and pool distribution. Conversely, the similar trend with altitude of the microbial activity indexes would indicate temperature to be crucial for the activity of the soil microbial community.

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