Warming affects seasonal dynamics of microorganisms and reduces the N storage capacity of soil microbes in winter

2021 ◽  
Author(s):  
Philipp Gündler ◽  
Alberto Canarini ◽  
Sara Marañón Jiménez ◽  
Gunnhildur Gunnarsdóttir ◽  
Páll Sigurðsson ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Growth Rates ◽  
Seasonal Dynamics ◽  
Soil Microbes ◽  
Storage Capacity ◽  
Ambient Conditions ◽  
Soil Warming ◽  
Carbon Use Efficiency ◽  
Use Efficiency ◽  
C And N

<p>Seasonality of soil microorganisms plays a critical role in terrestrial carbon (C) and nitrogen (N) cycling. The asynchrony of immobilization by microbes and uptake by plants may be important for N retention during winter, when plants are inactive. Meanwhile, the known warming effects on soil microbes (decreasing biomass and increasing growth rates) may affect microbial seasonal dynamics and nutrient retention during winter.</p><p>We sampled soils from a geothermal warming site in Iceland (www.forhot.is) which includes three in situ warming levels (ambient, +3 °C, +6 °C). We harvested soil samples at 9 time points over one year and measured the seasonal variation in microbial biomass carbon (Cmic) and nitrogen (Nmic) and microbial physiology (growth and carbon use efficiency) by an <sup>18</sup>O-labelling technique.</p><p>We observed that Cmic and Nmic peaked in winter, followed by a decline in spring and summer. In contrast growth and respiration rates were higher in summer than winter. The observed biomass peak at lower growth rates, suggests that microbial death rates must have declined even more than growth rates. Soil warming increased biomass-specific microbial activity (i.e., growth, respiration, and turnover rates per unit of microbial biomass), prolonging the period of higher microbial activity found in summer into autumn and winter. Microbial carbon use efficiency was unaltered by soil warming. Throughout the seasons, warming reduced Cmic and Nmic, albeit with a stronger effect in winter than summer and restrained winter biomass accumulation by up to 78% compared to ambient conditions. We estimated a reduced microbial winter N storage capacity by 45.5 and 94.6 kg ha<sup>-1</sup> at +3 °C and +6 °C warming respectively compared to ambient conditions. This reduction represents 1.57% and 3.26% of total soil N stocks, that could potentially be lost per year from these soils.</p><p>Our results clearly demonstrate that soil warming strongly decreases microbial C and N immobilization when plants are inactive, potentially leading to higher losses of C and N from warmed soils over winter. These results have important implications as increased N losses may restrict increased plant growth in a future climate.</p>

Seasonal dynamics of soil microbial biomass C and N in different habitats in Zhalong Wetland

2014 ◽  
Vol 34 (13) ◽  
Author(s):  
张静 ZHANG Jing ◽  
马玲 MA Ling ◽  
丁新华 DING Xinhua ◽  
陈旭日 CHEN Xuri ◽  
马伟 MA Wei
Keyword(s):  
Microbial Biomass ◽  
Seasonal Dynamics ◽  
Soil Microbial Biomass ◽  
Microbial Biomass C ◽  
Soil Microbial Biomass C ◽  
Soil Microbial ◽  
Zhalong Wetland ◽  
C And N

Seasonal Dynamics of Soil Microorganism in Zhalong Reed Wetland

2011 ◽  
Vol 71-78 ◽  
pp. 2992-2998
Author(s):  
Ling Ma ◽  
Sheng Nan Liu ◽  
Xin Hua Ding ◽  
Wei Ma
Keyword(s):  
Microbial Biomass ◽  
Seasonal Dynamics ◽  
Soil Microbial Biomass ◽  
Soil Microbes ◽  
Microbial Biomass Carbon ◽  
Organic Carbon Content ◽  
Biomass Carbon ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon

In this paper, the spatial distributions and seasonal dynamics of soil microbes and microbial biomass were investigated in a typical reed marsh in Zhalong natural wetlands.We wanted to explore the main factors that impacted their spatio-temporal patterns. The results showed that: Bacteria were dominant, followed by actinomyces and fungi were at least in the soil microbes community. The seasonal dynamics of soil microbial biomass carbon and nitrogen were more regularly, and their change patterns were significantly as "W" types. The response of soil microbial biomass in Bottom (10-30cm) to time was slower than the surface, and it fluctuated tinily in every months. The correlation analysis shows that the soil nutrient and soil microbial activity had close relationship. Soil microbial biomass carbon and nitrogen were all significantly positively correlated to quantities of fungus, organic carbon content and Alkali-hytrolyzabel N content(P<0.01), but negative extremely significantly correlated with pH (P<0.01).

Impacts of conservation agriculture on soil nitrogen pools and microbial physiology

2020 ◽  
Author(s):  
Jörg Schnecker ◽  
Gernot Bodner
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Nitrogen ◽  
Cover Crops ◽  
Organic N ◽  
Agricultural Fields ◽  
Total N ◽  
Carbon Use Efficiency ◽  
Regenerative Agriculture ◽  
Use Efficiency

&lt;p&gt;Conservation or regenerative agriculture, i.e. reduction of mechanical soil disturbance, introduction of crop rotations, and especially cover crops as a form of natural soil amendment, has been shown to increase soil organic matter contents as well as soil health. One mechanism behind the increase in organic carbon under regenerative agriculture could be an increase in microbial biomass, as well as an enhanced carbon use efficiency (CUE) of the soil microorganisms in these systems. Such changes in microbial biomass and activity could also influence soil nitrogen (N) cycling. Here we show first results of on-farm research at four sites in Austria comparing crop fields under regenerative agriculture practices with conventional practices, and nearby perennial grasslands at each site. The four sites span different climate gradients, soil types and textures.&lt;/p&gt;&lt;p&gt;Soil organic carbon (SOC) content ranged from 1 to 2.3% in the agricultural soils and was significantly higher under regenerative management compared to conventional practices in two out of four sites. SOC contents in perennial grasslands were up to 5% and always higher than in agricultural fields. Extractable organic carbon was similar in the two agricultural fields of the respective site, while grasslands diverged. Microbial biomass carbon was highest in grasslands at all sites and significantly higher in fields under regenerative agriculture compared to conventional agriculture at three out of four sites.&lt;/p&gt;&lt;p&gt;Total nitrogen was highest in perennial grasslands at all sites, and similar in regenerative and conventional fields. The form of N however differed between soils under conventional and regenerative agriculture. Dissolved N, expressed per g total N was significantly higher or tended to be higher in conventional compared to regenerative agricultural fields. From this dissolved pool a higher proportion was in inorganic N forms that are more prone to leaching and gaseous loss compared to organic N forms. In soils from regenerative agricultural fields a higher proportion of the total N was found in the microbial biomass. This pool is considered to be highly dynamic, but also protected against losses. Less N in dissolved and inorganic form as well as a higher proportion of N in the microbial biomass indicates that the N cycle is more closed in soils managed regeneratively versus conventional.&lt;/p&gt;&lt;p&gt;A greater importance of the microbial biomass could also have effects on soil C cycling. Higher microbial biomass is often related to increased carbon use efficiency, which in turn could indicate increased soil carbon sequestration. The already mentioned results will thus be discussed with further measurements of microbial respiration, growth and CUE.&lt;/p&gt;

scholarly journals Reduced carbon use efficiency and increased microbial turnover with soil warming

2018 ◽  
Vol 25 (3) ◽  
pp. 900-910 ◽  
Author(s):  
Jianwei Li ◽  
Gangsheng Wang ◽  
Melanie A. Mayes ◽  
Steven D. Allison ◽  
Serita D. Frey ◽  
...  
Keyword(s):  
Soil Warming ◽  
Carbon Use Efficiency ◽  
Microbial Turnover ◽  
Use Efficiency

scholarly journals Assessing microbial residues in soil as a potential carbon sink and moderator of carbon use efficiency

2020 ◽  
Vol 151 (2-3) ◽  
pp. 237-249
Author(s):  
Kevin Geyer ◽  
Jörg Schnecker ◽  
A. Stuart Grandy ◽  
Andreas Richter ◽  
Serita Frey
Keyword(s):  
Microbial Biomass ◽  
Carbon Sink ◽  
Meta Analysis ◽  
Clay Content ◽  
Tracer Experiment ◽  
Carbon Use Efficiency ◽  
Sequestration Potential ◽  
Use Efficiency ◽  
Microbial Products

AbstractA longstanding assumption of glucose tracing experiments is that all glucose is microbially utilized during short incubations of ≤2 days to become microbial biomass or carbon dioxide. Carbon use efficiency (CUE) estimates have consequently ignored the formation of residues (non-living microbial products) although such materials could represent an important sink of glucose that is prone to stabilization as soil organic matter. We examined the dynamics of microbial residue formation from a short tracer experiment with frequent samplings over 72 h, and conducted a meta-analysis of previously published glucose tracing studies to assess the generality of these experimental results. Both our experiment and meta-analysis indicated 30–34% of amended glucose-C (13C or 14C) was in the form of residues within the first 6 h of substrate addition. We expand the conventional efficiency calculation to include residues in both the numerator and denominator of efficiency, thereby deriving a novel metric of the potential persistence of glucose-C in soil as living microbial biomass plus residues (‘carbon stabilization efficiency’). This new metric indicates nearly 40% of amended glucose-C persists in soil 180 days after amendment, the majority as non-biomass residues. Starting microbial biomass and clay content emerge as critical factors that positively promote such long term stabilization of labile C. Rapid residue production supports the conclusion that non-growth maintenance activity can illicit high demands for C in soil, perhaps equaling that directed towards growth, and that residues may have an underestimated role in the cycling and sequestration potential of C in soil.

scholarly journals Does the ratio of β-1,4-glucosidase (BG) to β-1,4-N-acetylglucosaminidase (NAG) indicate the relative resource allocation of soil microbes to C and N acquisition?

2021 ◽  
Author(s):  
Taiki Mori ◽  
Ryota Aoyagi ◽  
Kanehiro Kitayama ◽  
Jiangming Mo
Keyword(s):  
Resource Allocation ◽  
Soil Microbes ◽  
Nutrient Status ◽  
N Fertilization ◽  
Published Data ◽  
Ambient Conditions ◽  
Polyphenol Oxidase Activity ◽  
Data Points ◽  
C And N ◽  
N Acquisition

AbstractThe ratio of β-1,4-glucosidase (BG) to β-1,4-N-acetylglucosaminidase (NAG) activity (BG:NAG ratio) is often used as an indicator of the relative resource allocation of soil microbes to C acquisition compared with N. An increasing number of recent studies have used this index to assess the nutrient status of microbes. However, the validity of this index for assessing the nutrient status of microbes is not well tested. In this study, we collected published data and tested that validity by investigating whether N fertilization elevated the BG:NAG ratio, assuming that microbes reduce their allocation to the N-acquiring enzyme (NAG) under N-enriched conditions. Of the data points, 54% (82/151) did not support the hypothesis because those studies showed lower BG:NAG ratios in N-enriched soils than under ambient conditions, especially when the ambient BG:NAG ratio was higher than 2.0 (77%, 59/77). This suggests that the BG:NAG ratio does not always indicate the microbial status for C or N limitation. Rather, we hypothesized that the decomposition stage explained the variation in BG:NAG because N addition accelerates decomposition, and the BG:NAG ratio is lower at later stages of decomposition due to the dominance of NAG-targeting C (chitin or peptidoglycan). A negative correlation of BG:NAG ratio with polyphenol oxidase activity, which increases with decomposition, supported our hypothesis.

Deuterium stable isotope probing of fatty acids reveals climate change effects on soil microbial physiology.

2021 ◽  
Author(s):  
Alberto Canarini ◽  
Lucia Fuchslueger ◽  
Jörg Schnecker ◽  
Margarete Watzka ◽  
Erich M. Pötsch ◽  
...  
Keyword(s):  
Climate Change ◽  
Fatty Acids ◽  
Water Vapor ◽  
Soil Water ◽  
Growth Rates ◽  
Microbial Growth ◽  
Community Level ◽  
Microbial Physiology ◽  
Carbon Use Efficiency ◽  
Use Efficiency

&lt;p&gt;The raise of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations, with consequent increase in global warming and the likelihood of severe droughts, is altering the terrestrial biogeochemical carbon (C) cycle, with potential feedback to climate change. &amp;#160;Microbial physiology, i.e. growth, turnover and carbon use efficiency, control soil carbon fluxes to the atmosphere. Thus, improving our ability to accurately quantify microbial physiology, and how it is affected by climate change, is essential. Recent advances in the field have allowed the quantification of community-level microbial growth and carbon use efficiency in dry conditions via an &lt;sup&gt;18&lt;/sup&gt;O water vapor equilibration technique, allowing for the first time to evaluate microbial growth rates under drought conditions.&lt;/p&gt;&lt;p&gt;We modified the water vapor equilibration method using &lt;sup&gt;2&lt;/sup&gt;H-labelled water to estimate microbial community growth via deuterium incorporation into fatty acids. First, we verified that a rapid equilibration of &lt;sup&gt;2&lt;/sup&gt;H with soil water is possible. Then, we applied this approach to soil samples collected from a long-term climate change experiment (https://www.climgrass.at/) where warming, elevated atmospheric CO&lt;sub&gt;2&lt;/sub&gt; (eCO&lt;sub&gt;2&lt;/sub&gt;) and drought are manipulated in a full factorial combination. Samples were taken in the field during peak drought and one week after rewetting. We used a high-throughput method to extract phospho- and neutral- lipid fatty acids (PLFA and NLFA) and we measured &lt;sup&gt;2&lt;/sup&gt;H enrichment in these compounds via GC-IRMS.&lt;/p&gt;&lt;p&gt;Our results show that within 48 h, &lt;sup&gt;2&lt;/sup&gt;H in water vapor was in equilibrium with soil water and was detectable in microbial PLFA and NLFAs. We were able to quantify growth rates for different groups of microorganisms (Gram-positive, Gram-negative, Fungi and Actinobacteria) and calculate community level carbon use efficiency. We showed that a reduction of carbon use efficiency in the combined warming + eCO&lt;sub&gt;2&lt;/sub&gt; treatment was caused by a reduced growth of fungi and overall higher respiration rates. During drought, all groups showed a reduction in growth rates, albeit the reduction was stronger in bacteria than in fungi. Moreover, fungi accumulated high amounts of &lt;sup&gt;2&lt;/sup&gt;H into NLFAs, representing up to one third of the amount in PLFAs and indicating enhanced investment into storage compounds. This investment was still higher than in control plots two days after rewetting and returned to control levels within a week.&lt;/p&gt;&lt;p&gt;Our study demonstrates that climate change can have strong effects on microbial physiology, with group-specific responses to different climate change factors. Our approach has the benefit of using fatty acid biomarkers to improve resolution into community level growth responses to climate change. This allowed a quantification of group-specific growth rates and concomitantly a measurement of investment into reserve compounds.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document