Will the temperature sensitivity of Arctic soil bacterial communities alter under warmed soil conditions?

2021 ◽  
Author(s):  
Ruud Rijkers ◽  
Johannes Rousk ◽  
Rien Aerts ◽  
James Taylor Weedon
Keyword(s):  
Community Structure ◽  
Soil Respiration ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Climate Feedback ◽  
The Arctic ◽  
Soil Conditions ◽  
Soil Microbial ◽  
Arctic Soils ◽  
Soil Bacterial

<p>Soil temperatures are rising in the Arctic and will likely increase soil microbial activity. The magnitude of subsequent carbon effluxes is difficult to predict but is critical for evaluating the strength of the soil carbon-climate feedback as climate change intensifies. Soil respiration in the Arctic has a relatively high sensitivity to temperature increases. This is hypothesized to be a consequence of physiological adaptation of soil microbial communities to low temperatures. A variety of experimental and gradient studies have suggested that the growth-temperature relationship of bacterial communities will adapt to soil warming.  It remains an open question whether this is driven by changes in community structure. In order to test this hypothesis, we collected 8 soils from the sub- to High Arctic and exposed them to a 0-30 ⁰C temperature gradient. We determined the temperature relationships and community composition of the resulting bacterial communities. To account for substrate depletion we sampled both after 100 days, as well as after a standardized amount of respiration. Temperature relationships were computed by fitting a square root model to leucine incorporation rates measured from 0-40 ⁰C. We will show the relationship between legacy effects of the soil thermal regime and the degree of temperature adaption and discuss whether the soil bacterial community structure is likely to influence soil respiration in Arctic soils under future climate conditions.</p>

scholarly journals Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

2018 ◽  
Vol 15 (6) ◽  
pp. 1879-1894 ◽  
Author(s):  
Petr Kotas ◽  
Hana Šantrůčková ◽  
Josef Elster ◽  
Eva Kaštovská
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
High Arctic ◽  
The Arctic ◽  
Soil Parameters ◽  
Organic Carbon Content ◽  
Soil Microbial ◽  
Environmental Controls ◽  
Arctic Soils ◽  
Tundra Ecosystem

Abstract. The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

scholarly journals Activation of the SA-Associated Plant Defense Pathway Alters the Composition of Soil Bacterial Communities

2021 ◽  
Author(s):  
Jing Zhang ◽  
Peter G.L. Klinkhamer ◽  
Klaas Vrieling ◽  
T. Martijn Bezemer
Keyword(s):  
Plant Growth ◽  
Microbial Communities ◽  
Signaling Pathway ◽  
Bacterial Communities ◽  
Rhizosphere Soil ◽  
Soil Microbial Communities ◽  
Core Microbiome ◽  
Soil Microbial ◽  
Soil Bacterial ◽  
Sa Signaling

Abstract Background and aimsMany plant species grow better in sterilized than in live soil. Foliar application of SA mitigates this negative effect of live soil on the growth of the plant Jacobaea vulgaris. To examine what causes the positive effect of SA application on plant growth in live soils, we analyzed the effects of SA application on the composition of active rhizosphere bacteria in the live soil. Methods We studied this over four consecutive plant cycles (generations), using mRNA sequencing of the microbial communities in the rhizosphere of J. vulgaris. ResultsOur study shows that the composition of the rhizosphere bacterial communities of J. vulgaris greatly differed among generations. Application of SA resulted in both increases and decreases in a number of active bacterial genera in the rhizosphere soil, but the genera that were affected by the treatment differed among generations. In the first generation, there were no genera that were significantly affected by the SA treatment, indicating that induction of the SA defense pathway in plants does not lead to immediate changes in the soil microbial community. 89 species out of the total 270 (32.4%) were present in all generations in all soils of SA-treated and control plants suggesting that these make up the “core” microbiome. On average in each generation, 72.9% of all genera were present in both soils. Application of SA to plants significantly up-regulated genera of Caballeronia, unclassified Cytophagaceae, Crinalium and Candidatus Thermofonsia Clade 2, and down-regulated genera of Thermomicrobiales, unclassified Rhodobacterales, Paracoccus and Flavihumibacter. While the functions of many of these bacteria are poorly understood, bacteria of the genus Caballeronia play an important role in fixing nitrogen and promoting plant growth, and hence this suggests that activation of the SA signaling pathway in J. vulgaris plants may select for bacterial genera that are beneficial to the plant. ConclusionsOverall, our study shows that aboveground activation of defenses in the plant affects soil microbial communities and, as soil microbes can greatly influence plant performance, this implies that induction of plant defenses can lead to complex above-belowground feedbacks. Further studies should examine how activation of the SA signaling pathway in the plant changes the functional genes of the rhizosphere soil bacterial community.

scholarly journals Management and Soil Conditions Influence Common Scab Severity on Potato Tubers Via Indirect Effects on Soil Microbial Communities

2020 ◽  
Vol 110 (5) ◽  
pp. 1049-1055
Author(s):  
Emily W. Lankau ◽  
Dianne Xue ◽  
Rachel Christensen ◽  
Amanda J. Gevens ◽  
Richard A. Lankau
Keyword(s):  
Microbial Communities ◽  
Indirect Effects ◽  
Common Scab ◽  
Soil Microbial Communities ◽  
Farm Management ◽  
Equation Modeling ◽  
Soil Conditions ◽  
Potato Market ◽  
Soil Microbial ◽  
Soil Bacterial

Common scab, caused by Streptomyces scabies and related species, is a potato tuber blemish disease that causes reductions in marketable yield worldwide. Evidence of suppression of common scab by indigenous soil microbial populations has been found in several studies. However, we lack a comprehensive understanding of how common scab severity relates functionally to potato varieties, farming systems, soil physical and chemical properties, and soil microbial communities. These factors may affect disease directly or indirectly by affecting one of the other variables. We performed a survey of 30 sampling locations across 12 fields in Wisconsin and used structural equation modeling to disentangle the direct effects of potato market classes, farm management (conventional versus organic), and soil physiochemical properties on common scab severity from their indirect effects mediated through soil bacterial and fungal communities. We found that, although potato market classes affected disease severity directly, the effects of farm management and soil physiochemistry were best explained as indirect, mediated by their impacts on soil bacterial communities. This suggests that evaluating the consequences of specific management practices for soil microbial communities may be useful for understanding disease pressure across fields.

scholarly journals Urbanization-induced environmental changes strongly affect wetland soil bacterial community composition and diversity

2021 ◽  
Author(s):  
Xinyu Yi ◽  
Chen Ning ◽  
Shuailong Feng ◽  
Haiqiang Gao ◽  
Jianlun Zhao ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Environmental Changes ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Environmental Drivers ◽  
Wetland Soil ◽  
Rrna Gene ◽  
Soil Microbial ◽  
Soil Bacterial

Abstract Soil microbial communities potentially serve as indicators for their responses to changes in various ecosystems at scales from a region to the globe. However, changes in wetland soil bacterial communities and how they are related to urbanization intensities remains poorly understood. Here, we collected sixty soil samples along urbanization intensity gradients from twenty wetlands. We measured a range of environmental factors and characterized bacterial communities structure using 16S rRNA gene amplicon sequencing that targeted the V4-V5 region. Our results revealed the dominant soil microbial phyla included Proteobacteria (39.3%), Acidobacteria (21.4%) and Chloroflexi (12.3%) in the wetlands, and showed a significant divergence of composition in intensive urbanization area (UI_4) than other places. A critical "threshold" exists in the soil bacterial diversity, demonstrating different patterns: a gradual increase in the areas of low-to-intermediate disturbances but a significant decrease in highly urbanized areas where metabolic functions were significantly strong. Additionally, soil pH, total phosphorus (TP), available phosphorus (AP ) and ammonia nitrogen (NH4+-N) made a significant contribution to variations in bacterial communities, explaining 49.6%, 35.1%, 26.2% and 30.7% of the total variance, respectively. pH and NH4+-N were identified as the main environmental drivers to determine bacterial community structure and diversity in the urban wetlands. Our results highlight collective changes in multiple environmental variables induced by urbanization rather than by the proportion of impervious surface area (ISA), which were potentially attributed to the spatial heterogeneity along different urbanization gradients.

scholarly journals Labile carbon limits late winter microbial activity near Arctic treeline

2020 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Madeline C. Stokes ◽  
Cameron K. McMillan ◽  
Michael N. Weintraub
Keyword(s):  
Nutrient Cycling ◽  
Microbial Activity ◽  
Microbial Respiration ◽  
Soil Microbial Communities ◽  
The Arctic ◽  
Late Winter ◽  
Soil Microbial ◽  
Arctic Soils ◽  
Labile C ◽  
Soil Temperatures

It is well established that soil microbial communities remain active during much of the Arctic winter, despite soil temperatures that are often well below −10°C1. Overwinter microbial activity has important effects on global carbon (C) budgets2, nutrient cycling and vegetation community composition3. Microbial respiration is highly temperature sensitive in frozen soils, as liquid water and solute availability decrease rapidly with declining temperature4. Thus, temperature is considered the ultimate control on overwinter soil microbial activity in the Arctic. Warmer winter soils are thought to yield greater microbial respiration of available C, greater overwinter CO2 efflux and a flush of nutrients that could be available for plant uptake at thaw3. Rising air temperature, combined with changes in timing and/or depth of snowpack development, is leading to warmer Arctic winter soils5. Using observational and experimental approaches in the field and in the laboratory, we demonstrate that persistently warm winter soils can lead to labile C starvation of the microbial community and reduced respiration rates, despite the high C content of most arctic soils. If Arctic winter soil temperatures continue to rise, microbial C limitation will reduce cold season CO2 emissions and alter soil nutrient cycling, if not countered by greater labile C inputs.

scholarly journals Biochar affects the structure rather than the total biomass of microbial communities in temperate soils

2013 ◽  
Vol 22 (4) ◽  
pp. 404-423 ◽  
Author(s):  
Elena Anders ◽  
Andrea Watzinger ◽  
Franziska Rempt ◽  
Barbara Kitzler ◽  
Bernhard Wimmer ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Field Experiments ◽  
Soil Microbial Communities ◽  
Greenhouse Experiment ◽  
Soil Conditions ◽  
Total Biomass ◽  
Soil Microbial ◽  
Temperate Soils

Biochar application is a promising strategy for sequestering carbon in agricultural soils and for improving degraded soils. Nonetheless, contradictory and unsettled issues remain. This study investigates whether biochar influences the soil microbial biomass and community structure using phospholipid fatty acid (PLFA) analysis. We monitored the effects of four different types of biochar on the soil microbial communities in three temperate soils of Austria over several months. A greenhouse experiment and two field experiments were conducted. The biochar application did not significantly increase or decrease the microbial biomass. Only the addition of vineyard pruning biochar pyrolysed at 400°C caused microbial biomass to increase in the greenhouse experiment. The biochar treatments however caused shifts in microbial communities (visualized by principal component analysis). We concluded that the shifts in the microbial community structure are an indirect rather than a direct effect and depend on soil conditions and nutrient status.

scholarly journals Soil Bacterial and Fungal Community Responses to Throughfall Reduction in a Eucalyptus Plantation in Southern China

Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Yubiao Lin ◽  
Jiejun Kong ◽  
Ling Yang ◽  
Qian He ◽  
Yan Su ◽  
...  
Keyword(s):  
Community Structure ◽  
Relative Abundance ◽  
Fungal Community ◽  
Southern China ◽  
Soil Microbial Communities ◽  
Fungal Communities ◽  
Eucalyptus Plantation ◽  
Soil Microbial ◽  
Soil Bacterial ◽  
Throughfall Reduction

In subtropical plantations in southern China, how soil microbial communities respond to climate change-induced drought is poorly understood. A field experiment was conducted in a subtropical Eucalyptus plantation to determine the impacts of 50% of throughfall reduction (TR) on soil microbial community composition, function, and soil physicochemical properties. Results showed that TR reduced soil water content (SWC) and soil available phosphorus (AP) content. TR significantly altered 196 bacterial operational taxonomic units (OTUs), most of them belonging to Acidobacteria, Actinobacteria, and Proteobacteria, while there were fewer changes in fungal OTUs. At the phylum level, TR increased the relative abundance of Acidobacteria at 0–20 cm soil depth by 37.18%, but failed to influence the relative abundance of the fungal phylum. Notably, TR did not alter the alpha diversity of the bacterial and fungal communities. The redundancy analysis showed that the bacterial communities were significantly correlated with SWC, and fungal communities were significantly correlated with AP content. According to predictions of bacterial and fungal community functions using PICRUSt2 and FUNGuild platforms, TR had different effects on both bacterial and fungal communities. Overall, SWC and AP decreased during TR, resulting in greater changes in soil bacterial community structure, but did not dramatically change soil fungal community structure.

scholarly journals Variations in soil nutrient dynamics and bacterial communities in long-term tea monoculture production systems

2021 ◽  
Author(s):  
Heng Gui ◽  
Lichao Fan ◽  
Donghui Wang ◽  
Peng Yan ◽  
Xin Li ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Nutrient Dynamics ◽  
Soil Microbial Communities ◽  
Soil Nutrient ◽  
Stand Age ◽  
Soil Microbial ◽  
Soil Bacterial Communities ◽  
Tea Plantations ◽  
Soil Bacterial

AbstractLong-term monoculture agriculture systems could lead to soil degradation and yield decline. The ways in which soil microbiotas interact with one another, particularly in response to long-term tea monoculture systems are currently unclear. In this study, through the comparison of three independent tea plantations across eastern China composed of varying stand ages (from 3 years to 90 years after conversion from forest), we found that long-term tea monoculture led to significant increases in soil total organic carbon (TOC) and microbial nitrogen (MBN). Additionally, the structure, function and co-occurrence network of soil microbial communities were investigated by pyrosequencing 16S rRNA genes. The pyrosequencing analysis revealed that structures and functions of soil bacterial communities were significantly affected by different stand ages of tea plantations, but sampling sites and land-use conversion (from forest to tea plantation) still outcompeted stand age to control the diversity and structure of soil bacterial communities. Further RDA analysis revealed that the C and N availability improvement in tea plantation soils led to variation of structure and function in soil microbial communities. Moreover, co-occurrence network analysis of soil bacterial communities also demonstrated that interactions among soil bacteria taxa were strengthened with the increasing stand age of respective tea stands. Overall, this study provides a comprehensive understanding of the impact of long-term monoculture stand age on soil nutrient dynamics and bacterial communities in tea production.

scholarly journals Community Structure Analyses Are More Sensitive to Differences in Soil Bacterial Communities than Anonymous Diversity Indices

2006 ◽  
Vol 72 (12) ◽  
pp. 7804-7812 ◽  
Author(s):  
Martin Hartmann ◽  
Franco Widmer
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Rflp Analysis ◽  
Diversity Indices ◽  
Soil Bacterial Community ◽  
Community Structures ◽  
Soil Microbial ◽  
Soil Bacterial

ABSTRACT Changes in the diversity and structure of soil microbial communities may offer a key to understanding the impact of environmental factors on soil quality in agriculturally managed systems. Twenty-five years of biodynamic, bio-organic, or conventional management in the DOK long-term experiment in Switzerland significantly altered soil bacterial community structures, as assessed by terminal restriction fragment length polymorphism (T-RFLP) analysis. To evaluate these results, the relation between bacterial diversity and bacterial community structures and their discrimination potential were investigated by sequence and T-RFLP analyses of 1,904 bacterial 16S rRNA gene clones derived from the DOK soils. Standard anonymous diversity indices such as Shannon, Chao1, and ACE or rarefaction analysis did not allow detection of management-dependent influences on the soil bacterial community. Bacterial community structures determined by sequence and T-RFLP analyses of the three gene libraries substantiated changes previously observed by soil bacterial community level T-RFLP profiling. This supported the value of high-throughput monitoring tools such as T-RFLP analysis for assessment of differences in soil microbial communities. The gene library approach also allowed identification of potential management-specific indicator taxa, which were derived from nine different bacterial phyla. These results clearly demonstrate the advantages of community structure analyses over those based on anonymous diversity indices when analyzing complex soil microbial communities.

scholarly journals Shift of bacterial communities in heavy metal-contaminated agricultural land during a remediation process

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255137
Author(s):  
Chi-Chun Huang ◽  
Chih-Ming Liang ◽  
Ting-I Yang ◽  
Jiann-Long Chen ◽  
Wei-Kuang Wang
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Community Structure ◽  
Microbial Communities ◽  
Contaminated Soil ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Soil Environment ◽  
Soil Microbial ◽  
Remediation Process

Anthropogenic activities accompanied by heavy metal waste threaten the environment. Heavy metal pollution alters the soil microbial community composition, and the microorganisms that adapt to this stress increase in abundance. The remediation process of contaminated soil not only reduces the concentration of heavy metals but also alters the bacterial communities. High-throughput 16S rDNA sequencing techniques were applied to understand the changes in soil microbial communities. Using the remediation approach of the soil mixing, the concentrations of heavy metals in the contaminated areas were diluted and the soil environment was changed. The change of soil environment as a disturbance contributed to the alteration of microbial diversity of the remediated areas. The pH and heavy metals (Cr, Cu, Ni, and Zn) were the most influential factors driving the changes in community structure. The bacterial community structure was significantly different among sample areas. The decrease of heavy metals in soil may be the important factors that changed the microbial composition. This study provides the better understanding of the changes in composition of microbial communities affected by the remediation process in heavy metal-contaminated soil.

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