scholarly journals Do soil bacterial communities respond differently to abrupt or gradual additions of copper?

2018 ◽  
Vol 95 (1) ◽  
Author(s):  
Michael McTee ◽  
Lorinda Bullington ◽  
Matthias C Rillig ◽  
Philip W Ramsey

ABSTRACTMany experiments that measure the response of microbial communities to heavy metals increase metal concentrations abruptly in the soil. However, it is unclear whether abrupt additions mimic the gradual and often long-term accumulation of these metals in the environment where microbial populations may adapt. In a greenhouse experiment that lasted 26 months, we tested whether bacterial communities and soil respiration differed between soils that received an abrupt or a gradual addition of copper or no copper at all. Bacterial richness and other diversity indices were consistently lower in the abrupt treatment compared to the ambient treatment that received no copper. The abrupt addition of copper yielded different initial bacterial communities than the gradual addition; however, these communities appeared to converge once copper concentrations were approximately equal. Soil respiration in the abrupt treatment was initially suppressed but recovered after four months. Afterwards, respiration in both the gradual and abrupt treatments wavered between being below or equal to the ambient treatment. Overall, our study indicates that gradual and abrupt additions of copper can yield similar bacterial communities and respiration, but these responses may drastically vary until copper concentrations are equal.

2021 ◽  
Vol 309 ◽  
pp. 107285
Author(s):  
Mengyu Gao ◽  
Jinfeng Yang ◽  
Chunmei Liu ◽  
Bowen Gu ◽  
Meng Han ◽  
...  

2019 ◽  
Author(s):  
Myrto Tsiknia ◽  
Stilianos Fodelianakis ◽  
Nikolaos P. Nikolaidis ◽  
Nikolaos V. Paranychianakis

AbstractThere is a renewed interest in recent years on the ecological processes (stochastic vs selective) driving the assembly of microbial communities. Such information could potentially improve our understanding on ecosystem functioning and resilience to disturbances, ecosystem response to environmental shifts, and adoption of sustainable soil management practices. Herein, employing a suite of existing methodologies, we show that stochastic processes have an important role on the assembly of soil bacterial communities at a Mediterranean watershed. Moreover, we document that the relative contribution of assembly processes varies over the years. The observed intensification of stochastic processes was accompanied by a decrease in the contribution of variable selection in favor of homogeneous selection and dispersal and this trend was only marginally affected by land use (natural vs agricultural lands) or soil depth. Our study also revealed a high inter-annual turnover of soil microbial communities that was likely stimulated by the weak environmental selection and the prevailing environmental conditions (drying-wetting cycles) in Mediterranean landscapes, implying potential impacts on ecosystem functioning and our ability to predict soil response to environmental shifts. Using nitrogen mineralization rate (NMR) as a representative function we document highly variable NMR over the sampling years, land uses and soil depths and lack of significant associations with the monitored environmental variables and individual taxa. In summary, our study provides novel insights on the organization and functioning of microbial communities at Mediterranean ecosystems and sets directions towards a more advanced understanding of the relationships among environmental factors, microbial community structure, and ecosystem functioning that could contribute to sustainable management of these severely degraded ecosystems.


2017 ◽  
Vol 59 ◽  
pp. 498-507 ◽  
Author(s):  
Jongkeun Lee ◽  
Joonrae Roger Kim ◽  
Seulki Jeong ◽  
Jinwoo Cho ◽  
Jae Young Kim

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Noriko A. Cassman ◽  
Marcio F. A. Leite ◽  
Yao Pan ◽  
Mattias de Hollander ◽  
Johannes A. van Veen ◽  
...  

SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 595-609
Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits for improving soil organic matter content and reducing soil erosion. However, the effects of long-term straw mulching under a no-till system on soil physicochemical properties and bacterial communities at different soil depths are still unclear. In this 12-year experiment of straw removal (CK) and straw mulching (SM) treatments, soil samples were collected at 0–5, 5–10, 10–20, and 20–30 cm soil depths. The results showed that the contents of organic carbon (C), nitrogen (N), and phosphorus (P) fractions, and bacterial abundance significantly decreased, whereas pH significantly increased with soil depth. Compared with CK, SM significantly increased total N, inorganic N, available P, available potassium, and soil water content at 0–5 cm, total organic C content at 0–10 cm, and dissolved organic C and N contents at 0–20 cm. Regarding bacterial communities, SM increased the relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria but reduced those of Actinobacteria, Chloroflexi, and Cyanobacteria. Bacterial Shannon diversity and Shannon's evenness at 0–5 cm were reduced by SM treatment compared to CK treatment. Furthermore, SM increased the relative abundances of some C-cycling genera (such as Terracidiphilus and Acidibacter) and N-cycling genera (such as Rhodanobacter, Rhizomicrobium, Dokdonella, Reyranella, and Luteimonas) at 0–5 cm. Principal coordinate analysis showed that the largest difference in the composition of soil bacterial communities between CK and SM occurred at 0–5 cm. Soil pH and N and organic C fractions were the major drivers shaping soil bacterial communities. Overall, SM treatment is highly recommended under a no-till system because of its benefits to soil fertility and bacterial abundance.


2018 ◽  
Vol 70 (4) ◽  
pp. 707-716
Author(s):  
Olivera Stajkovic-Srbinovic ◽  
Aneta Buntic ◽  
Natasa Rasulic ◽  
Djordje Kuzmanovic ◽  
Zoran Dinic ◽  
...  

Soil chemical properties and total heavy metal concentrations (As, Cd, Cr, Cu, Ni, Pb, Zn, Fe and Mn) and their relationships with some soil microbiological characteristics (such as soil respiration and numbers of specific groups of microorganisms) were evaluated in agricultural soils in southern Serbia. In 42% of samples, slightly elevated concentrations of As, Ni and/or Pb were detected, with the highest values of 43.4, 64.4 and 184.1 mg/kg, respectively. No significant differences were observed in soil microbiological characteristics between soil samples with elevated heavy metals and heavy metals below the maximum allowed concentrations (MAC). There was no negative correlation between any of the heavy metals and any microbiological characteristics, except the total number of fungi and the concentration of Ni (r=-394). Positive correlations between most of the heavy metals and the number of Azotobacter were obtained. Correlation analysis and stepwise multiple regression analyses indicated that the chemical properties of the soil are the factors that affected the number of microorganisms the most. The content of CaCO3 significantly contributed to variations in soil respiration (39%), the total number of microorganisms was affected the most by humus (53%), oligonitrophiles by the total N content (49%), while the numbers of actinomycetes and fungi were affected by the pH (48% and 58% of the variation).


Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2425
Author(s):  
Juan Li ◽  
Yanchen Wen ◽  
Xiangdong Yang

Studies of soil DNA-based and RNA-based bacterial communities under contrasting long-term fertilization regimes can provide valuable insights into how agricultural management affects soil microbial structure and functional diversity. In this study, soil bacterial communities subjected to six fertility treatments in an alkaline soil over 27 years were investigated by 454 pyrosequencing based on 16S rDNA and 16S rRNA. Long-term fertilization showed significant influences on the diversity of the soil DNA-based bacteria, as well as on their RNA-based members. The top five phyla (Proteobacteria, Acidobacteria, Chloroflexi, Actinobacteria, and Planctomycetes) were found in both the DNA- and RNA-based samples. However, the relative abundances of these phyla at both DNA and RNA levels were showed significantly different. Analysis results showed that the diversity of the 16S rRNA samples was consistently lower than that of the rDNA samples, however, 16S rRNA samples had higher relative abundance. PICRUSt analysis indicated that glycan biosynthesis and metabolism were detected mainly in the DNA samples, while metabolism and degradation of xenobiotics and the metabolism of amino acids, terpenoids and polyketides were relatively higher in the RNA samples. Bacilli were significantly more abundant in all the OM-fertilized soils. Redundancy analysis indicated that the relative abundances of both DNA- and RNA-based bacterial groups were correlated with soil total organic carbon content, nitrogen content, Olsen-P, and soil pH. Moreover, the RNA-based Bacilli were positively correlated with available phosphorus (Olsen-P).


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