scholarly journals Nitrogen Addition Affects Soil Respiration Primarily through Changes in Microbial Community Structure and Biomass in a Subtropical Natural Forest

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 435 ◽  
Author(s):  
Jiacong Zhou ◽  
Xiaofei Liu ◽  
Jinsheng Xie ◽  
Maokui Lyu ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Forest Soil ◽  
Microbial Community Structure ◽  
N Deposition ◽  
N Addition ◽  
C Cycling ◽  
Total Plfa

Forest soil respiration plays an important role in global carbon (C) cycling. Owing to the high degree of C and nitrogen (N) cycle coupling, N deposition rates may greatly influence forest soil respiration, and possibly even global C cycling. Soil microbes play a crucial role in regulating the biosphere–atmosphere C exchange; however, how microbes respond to N addition remains uncertain. To better understand this process, the experiment was performed in the Castanopsis kawakamii Hayata Nature Reserve, in the subtropical zone of China. Treatments involved applying different levels of N (0, 40, and 80 kg ha−2 year−1) over a three-year period (January 2013–December 2015) to explore how soil physicochemical properties, respiration rate, phospholipid fatty acid (PLFA) concentration, and solid state 13C nuclear magnetic resonance responded to various N addition rate. Results showed that high levels of N addition significantly decreased soil respiration; however, low levels of N addition significantly increased soil respiration. High levels of N reduced soil pH and enhanced P and C co-limitation of microorganisms, leading to significant reductions in total PLFA and changes in the structure of microbial communities. Significant linear relationships were observed between annual cumulative respiration and the concentration of microbial biomass (total PLFA, gram-positive bacteria (G+), gram-negative bacteria (G−), total bacteria, and fungi) and the microbial community structure (G+: G− ratio). Taken together, increasing N deposition changed microbial community structure and suppressed microbial biomass, ultimately leading to recalcitrant C accumulation and soil C emissions decrease in subtropical forest.

Microbial Community Structure and Density Under Different Tree Species in an Acid Forest Soil (Morvan, France)

2005 ◽  
Vol 50 (4) ◽  
pp. 614-625 ◽  
Author(s):  
David P. H. Lejon ◽  
Rémi Chaussod ◽  
Jacques Ranger ◽  
Lionel Ranjard
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Forest Soil ◽  
Microbial Community Structure ◽  
Tree Species ◽  
Acid Forest Soil

scholarly journals Predation by protists influences the temperature response of microbial communities

2021 ◽  
Author(s):  
Jennifer D Rocca ◽  
Andrea Yammine ◽  
Marie Simonin ◽  
Jean Gibert
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Temperature Response ◽  
Global Carbon Cycle ◽  
Structure And Function ◽  
And Function ◽  
Global Carbon

Temperature strongly influences microbial community structure and function, which in turn contributes to the global carbon cycle that can fuel further warming. Recent studies suggest that biotic interactions amongst microbes may play an important role in determining the temperature responses of these communities. However, how microbial predation regulates these communities under future climates is still poorly understood. Here we assess whether predation by one of the most important bacterial consumers globally, protists, influences the temperature response of a freshwater microbial community structure and function. To do so, we exposed these microbial communities to two cosmopolitan species of protists at two different temperatures, in a month-long microcosm experiment. While microbial biomass and respiration increased with temperature due to shifts in microbial community structure, these responses changed over time and in the presence of protist predators. Protists influenced microbial biomass and function through effects on community structure, and predation actually reduced microbial respiration rate at elevated temperature. Indicator species and threshold indicator taxa analyses showed that these predation effects were mostly determined by phylum-specific bacterial responses to protist density and cell size. Our study supports previous findings that temperature is an important driver of microbial communities, but also demonstrates that predation can mediate these responses to warming, with important consequences for the global carbon cycle and future warming.

scholarly journals Nitrogen Addition Alleviates Microbial Nitrogen Limitations and Promotes Soil Respiration in a Subalpine Coniferous Forest

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1038 ◽  
Author(s):  
Yang Liu ◽  
Qianmei Chen ◽  
Zexi Wang ◽  
Haifeng Zheng ◽  
Yamei Chen ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Respiration ◽  
Soil Microbes ◽  
N Deposition ◽  
Subalpine Forest ◽  
N Addition ◽  
Subalpine Forests ◽  
N Application ◽  
Microbial Nitrogen ◽  
Microbial Groups

Soil microbes are an important component of soil ecosystems that influence material circulation and are involved in the energy flow of ecosystems. The increase in atmospheric nitrogen (N) deposition affects all types of terrestrial ecosystems, including subalpine forests. In general, alpine and high-latitude ecosystems are N limited. Increased N deposition could therefore affect microbial activity and soil respiration. In this study, four levels of N addition, including CK (no N added), N1 (2 g m−2 a−1), N2 (5 g m−2 a−1), and N3 (10 g m−2 a−1), were carried out in a Sichuan redwood forest at the eastern edge of the Tibetan Plateau. The dynamics of soil respiration, major microbial groups, ecoenzymatic stoichiometry, and microbial biomass carbon and nitrogen (MBC and MBN, respectively) were investigated over a year. The results showed that N application significantly increased soil respiration (11%–15%), MBC (5%–9%), MBN (23%–34%), N-acetylglucosidase (56.40%–204.78%), and peroxidase (42.28%–54.87%) activities. The promotion of soil respiration, N-acetylglucosidase, and peroxidase was highest under the N2 treatment. The carbon, nitrogen, and phosphorus metabolism of soil microbes in subalpine forests significantly responded to N application. In the latter stages of N application, microbial metabolism changed from being N restricted to phosphorus restricted, especially under the N2 treatment. Soil bacteria (B) and gram-positive (G+) bacteria were the dominant microbial groups affecting soil respiration. Structural equation modelling indicated that N application significantly promoted soil respiration and microbial biomass, whereas the main microbial groups did not significantly respond to N application. Therefore, we conclude that short-term N addition alleviates microbial nitrogen limitation and promotes soil respiration in the subalpine forest ecosystem that accelerates soil carbon (C) and N cycling. Continuous monitoring is needed to elucidate the underlying mechanisms under long-term N deposition, which may help in forecasting C, N, and P cycling in the alpine region under global climate change.

Response of soil microbial biomass, activities, and community structure at a pine stand in northeastern Germany 5 years after thinning

2006 ◽  
Vol 36 (6) ◽  
pp. 1427-1434 ◽  
Author(s):  
Sebastian Maassen ◽  
Hannu Fritze ◽  
Stephan Wirth
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Community Structure ◽  
Basal Respiration ◽  
Organic Layer ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Significant Difference ◽  
Northeastern Germany

A thinned and an unthinned treatment were compared in a 62-year-old pine stand located in northeastern Germany (Brandenburg, Ost-Prignitz, Revier Beerenbusch) (year of thinning: 1999, degree of canopy opening: 0.4). Samples of the organic layer (O) and the mineral horizon (Aeh) of an acid brown earth were collected along a transect at each treatment in November 2003 and April 2004. Substrate induced respiration, basal respiration, and a suite of enzymes involved in the degradation of lignocellulose (endocellulase, exocellulase, β-glucosidase, endoxylanase, exoxylanase, phenoloxidase, peroxidase) were assayed. Microbial community structure and relative biomass of bacteria, actinomycetes, and fungi were assayed by phospholipid fatty acid analysis. Five years after thinning, microbial biomass, basal respiration, and enzyme activities in both soil layers did not differ significantly between thinned and unthinned treatments. However, the analysis of soil microbial community structure revealed a significant difference between the thinned and unthinned treatment at both sampling dates. Thus, it was concluded that thinning had not yet resulted in any response in soil microbial activities at the site under study, but since early evidence of change in the microbial community was detected, long-term monitoring and additional studies on mineralization activities are required.

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