scholarly journals Microbial dormancy improves predictability of soil respiration at the seasonal time scale

2018 ◽  
Author(s):  
A. Salazar ◽  
J.T. Lennon ◽  
J.S Dukes
Keyword(s):  
Climate Change ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Phospholipid Fatty Acid ◽  
Soil C ◽  
Metabolic States ◽  
Global Soil ◽  
Relative Abundances ◽  
Seasonal Time Scale ◽  
Microbial Groups

AbstractClimate change is accelerating global soil respiration, which could in turn accelerate climate change. The biological mechanisms through which soil carbon (C) responds to climate are not well understood, limiting our ability to predict future global soil respiration rates. As part of a climate manipulation experiment, we tested whether differences in soil heterotrophic respiration driven by season or climate treatment (RH) are linked to 1) relative abundances of microbes in active and dormant metabolic states, 2) net changes in microbial biomass and/or 3) changes in the relative abundances of microbial groups with different C-use strategies. We used a flow-cytometric single-cell metabolic assay to quantify the abundance of active and dormant microbes, and the phospholipid fatty acid (PLFA) method to determine microbial biomass and ratios of fungi:bacteria and Gram-positive:Gram-negative bacteria. RH did not respond to climate treatments but was greater in the warm and dry summer than in the cool and less-dry fall. These dynamics were better explained when microbial data were taken into account compared to when only physical data (temperature and moisture) were used. Overall, our results suggest that RH responses to temperature are stronger when soil contains more active microbes, and that seasonal patterns of RH can be better explained by shifts in microbial activity than by shifts in the relative abundances of fungi and Gram-positive and Gram-negative bacteria. These findings contribute to our understanding of how and under which conditions microbes influence soil C responses to climate.

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.

scholarly journals Model behavior of arbuscular mycorrhizal fungi: predicting soil carbon dynamics under climate change

Botany ◽  
2016 ◽  
Vol 94 (6) ◽  
pp. 417-423 ◽  
Author(s):  
Kathleen K. Treseder
Keyword(s):  
Climate Change ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Earth System ◽  
Soil C ◽  
System Models ◽  
Microbial Groups ◽  
Earth System Models

In this commentary, I advocate for more detailed incorporation of arbuscular mycorrhizal (AM) fungi in Earth system models, to improve our projections of global climate change. Current Earth system models display relatively low predictability of soil C stocks, which limit our ability to estimate future climate conditions. A more explicit incorporation of microbial mechanisms can increase the accuracy of ecosystem-scale models that inform the larger-scale Earth system models. Of the numerous microbial groups that can influence soil C dynamics, AM fungi are particularly tractable for integration in models. Arbuscular mycorrhizal fungi are globally abundant and perform critical roles in C cycling, such as augmentation of net primary productivity and soil C storage. Moreover, AM communities exhibit relatively low diversity within ecosystems, compared with other microbial groups. In addition, global datasets of AM ecology are available for use in model development. Thus, AM communities can be readily simulated in next-generation trait-based models that link microbial diversity to ecosystem function. Altogether, we are well-poised to incorporate the dynamics of individual AM taxa in ecosystem models, which can then be coupled to Earth system models. Hopefully, these efforts would advance our ability to predict and plan for future climate change.

scholarly journals Temporal changes in global soil respiration since 1987

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiesi Lei ◽  
Xue Guo ◽  
Yufei Zeng ◽  
Jizhong Zhou ◽  
Qun Gao ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Temporal Variations ◽  
Global Scale ◽  
Future Climate ◽  
Climate Projections ◽  
Microbial Decomposition ◽  
Soil C ◽  
Modeling Analysis ◽  
C Stocks ◽  
Global Soil

AbstractAs the second-largest terrestrial carbon (C) flux, soil respiration (RS) has been stimulated by climate warming. However, the magnitude and dynamics of such stimulations of soil respiration are highly uncertain at the global scale, undermining our confidence in future climate projections. Here, we present an analysis of global RS observations from 1987–2016. RS increased (P < 0.001) at a rate of 27.66 g C m−2 yr−2 (equivalent to 0.161 Pg C yr−2) in 1987–1999 globally but became unchanged in 2000–2016, which were related to complex temporal variations of temperature anomalies and soil C stocks. However, global heterotrophic respiration (Rh) derived from microbial decomposition of soil C increased in 1987–2016 (P < 0.001), suggesting accumulated soil C losses. Given the warmest years on records after 2015, our modeling analysis shows a possible resuscitation of global RS rise. This study of naturally occurring shifts in RS over recent decades has provided invaluable insights for designing more effective policies addressing future climate challenges.

scholarly journals Microbial carbon recycling – an underestimated process controlling soil carbon dynamics – Part 1: A long-term laboratory incubation experiment

2015 ◽  
Vol 12 (20) ◽  
pp. 5929-5940 ◽  
Author(s):  
A. Basler ◽  
M. Dippold ◽  
M. Helfrich ◽  
J. Dyckmans
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Arable Land ◽  
Isotope Analysis ◽  
Co2 Production ◽  
Incubation Experiment ◽  
Soil C ◽  
C Cycle ◽  
Global Soil ◽  
Silty Loam

Abstract. Independent of its chemical structure carbon (C) persists in soil for several decades, controlled by stabilization and recycling. To disentangle the importance of the two factors on the turnover dynamics of soil sugars, an important compound of soil organic matter (SOM), a 3-year incubation experiment was conducted on a silty loam soil under different types of land use (arable land, grassland and forest) by adding 13C-labelled glucose. The compound-specific isotope analysis of soil sugars was used to examine the dynamics of different sugars during incubation. Sugar dynamics were dominated by a pool of high mean residence times (MRT) indicating that recycling plays an important role for sugars. However, this was not substantially affected by soil C content. Six months after label addition the contribution of the label was much higher for microbial biomass than for CO2 production for all examined land use types, corroborating that substrate recycling was very effective within the microbial biomass. Two different patterns of tracer dynamics could be identified for different sugars: while fucose and mannose showed highest label contribution at the beginning of the incubation with a subsequent slow decline, galactose and rhamnose were characterized by slow label incorporation with subsequently constant levels, which indicates that recycling is dominating the dynamics of these sugars. This may correspond to (a) different microbial growing strategies (r and K-strategist) or (b) location within or outside the cell membrane (lipopolysaccharides vs. exopolysaccharides) and thus be subject of different re-use within the microbial food web. Our results show how the microbial community recycles substrate very effectively and that high losses of substrate only occur during initial stages after substrate addition. This study indicates that recycling is one of the major processes explaining the high MRT observed for many SOM fractions and thus is crucial for understanding the global soil C cycle.

Effect of soil warming and N availability on the fate of recent carbon in subarctic grassland

2020 ◽  
Author(s):  
Kathiravan Meeran ◽  
Niel Verbrigghe ◽  
Lucia Fuchslueger ◽  
Johannes Ingrisch ◽  
Sara Vicca ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Respiration ◽  
Nitrogen Addition ◽  
Interactive Effects ◽  
N Availability ◽  
Soil Warming ◽  
Soil System ◽  
Soil C ◽  
Microbial C ◽  
The Individual

&lt;p&gt;Climate warming has been suggested to impact high latitude grasslands severely, causing considerable carbon (C) losses from soil. Warming can also stimulate nitrogen (N) turnover, but it is largely unclear whether and how altered N availability impacts soil C dynamics. Even less is known about the individual and interactive effects of warming and N availability on the fate of recently photosynthesized C in soil. &amp;#160;We hypothesized that warming would increase belowground C allocation, while enhanced N availability would decrease it, and that their interactive effects would be additive.&lt;/p&gt;&lt;p&gt;We studied a subarctic grassland located at a natural geothermal soil warming gradient close to Hverager&amp;#240;i, Iceland, which was established by an earthquake in 2008. We chose 14 plots along the gradient with soil warming temperatures ranging from 0 to 10&amp;#176;C above ambient, and fertilized a subset of plots with 50kg ha&lt;sup&gt;-1&lt;/sup&gt; y&lt;sup&gt;-1&lt;/sup&gt; of NH&lt;sub&gt;4&lt;/sub&gt;NO&lt;sub&gt;3&lt;/sub&gt; twice a year prior to the study. We performed &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; canopy pulse labeling for an hour and tracked the &lt;sup&gt;13&lt;/sup&gt;C pulse through the plant-microbe-soil system and into soil respiration for ten days after labeling.&lt;/p&gt;&lt;p&gt;Our preliminary results show that at higher temperatures microbial activity increased, causing higher C turnover and a higher respiration of recently assimilated C from the soil. Warming significantly decreased microbial biomass, however, the recent C allocated from roots to microbes increased. This indicates a higher microbial C-limitation and a tighter root-microbe coupling under warming. Nitrogen addition increased the allocation of recent C to roots, microbial biomass, and soil respiration. The effects of N addition and warming were additive with no interaction. Our results indicate that the microbes in warmed soil may not be N limited, but could be C limited and depend more on the supply of recent C from plants. We conclude that in a future climate with warmer soils, more C may be allocated belowground, however, its residence time may decrease.&lt;/p&gt;

Short-term response of soil respiration and soil enzymatic activities to biochar application in semiarid agricultural soils under a climate change scenario

2021 ◽  
Author(s):  
Iria Benavente-Ferraces ◽  
Ana Rey ◽  
Marco Panettieri ◽  
Claudio Zaccone ◽  
Gabriel Gascó ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Respiration ◽  
Microbial Activity ◽  
Temperature Sensitivity ◽  
Soil Microbial Activity ◽  
Enzymatic Activities ◽  
C Mineralization ◽  
Soil C ◽  
Soil Microbial ◽  
Rainfall Reduction

&lt;p&gt;The application of biochar is presumed to be a climate change mitigation strategy in agriculture. However, we still need to better understand the effects of biochar application on soil properties, particularly on soil microbial activity. This is because soil microorganisms play a key role in ecosystems functioning, as they have a central role in soil metabolic activity given that they are responsible for soil organic matter decomposition and nutrient cycling. Conversely, little is known about how climate change will affect the soil microbial activity.&lt;/p&gt;&lt;p&gt;In a rainfed field experiment, we studied the effect of forecasted warming and rainfall reduction on soil respiration and soil enzymatic activities after 3 years of consecutive application of biochar at a rate of 20 t/ha on a barley-camelina-fallow rotation in a semiarid region in Central Spain. Soil respiration was not affected by the application of biochar or/and warming and rainfall reduction treatments in comparison to the control treatment (no amendment). However, biochar amended soils had lower temperature sensitivity of soil C mineralization in the first two years when soils were cultivated but higher temperature sensitivity of soil C mineralization in the third year during fallow treatment. Enzymes involved in the C and N cycles (dehydrogenase, &amp;#946;-glucosidase and urease) significantly increased their activity under warming and rainfall reduction treatments, albeit biochar application tended to decrease the enzymatic activity under those treatments.&lt;/p&gt;&lt;p&gt;Acknowledgments: to the Spanish MICINN (MINECO, AEI, FEDER, EU) for supporting the research projects AGL2016-75762-R and CGL2015-65162-R.&lt;/p&gt;

Extraction and methylation parameters of phospholipid fatty acid analysis and their effect on total yield and community structure

2021 ◽  
Author(s):  
Guido Wiesenberg ◽  
Cyrill Zosso
Keyword(s):  
Fatty Acids ◽  
Community Composition ◽  
Cell Walls ◽  
Phospholipid Fatty Acid ◽  
Total Yield ◽  
Fatty Acid Analysis ◽  
Phospholipid Fatty Acids ◽  
Acid Catalyzed ◽  
Relative Abundances ◽  
Microbial Groups

&lt;p&gt;Phospholipid fatty acids are membrane compounds of microbial cell walls and the structure of individual compounds is indicative for specific microbial groups. The extraction and analysis of phospholipid fatty acids in soils improved our understanding of factors driving microbial abundance and community composition. Despite the wide application of this method, important pitfalls persist which impede comparability of PLFA results between studies.&lt;/p&gt;&lt;p&gt;Here, we show that there was an effect of freeze-drying on the community composition. However, compared to the effect of using of old extraction solution (4 weeks) and two different methylation procedures, this effect seems negligible. Using old extraction solution, the overall yield of PLFA was 12% lower and and we observed significant differences in the relative abundances of functional microbial groups. But most importantly, base catalyzed methylation yielded 35% less PLFA compared to acid catalyzed methylation and the relative abundances of all microbial groups were completely different. Our results show that it is crucial to keep the analytical parameters constant to capture subtle treatment effects and that especially the use of different methylation methods prevents comparability between studies.&lt;/p&gt;

scholarly journals Spatial and temporal variations in global soil respiration and their relationships with climate and land cover

2020 ◽  
Vol 6 (41) ◽  
pp. eabb8508
Author(s):  
Ni Huang ◽  
Li Wang ◽  
Xiao-Peng Song ◽  
T. Andrew Black ◽  
Rachhpal S. Jassal ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Respiration ◽  
Land Cover ◽  
Land Cover Change ◽  
Statistical Models ◽  
Driving Forces ◽  
Remote Sensing Data ◽  
Terrestrial Ecosystems ◽  
Temporal Variations ◽  
Global Soil

Soil respiration (Rs) represents the largest flux of CO2 from terrestrial ecosystems to the atmosphere, but its spatial and temporal changes as well as the driving forces are not well understood. We derived a product of annual global Rs from 2000 to 2014 at 1 km by 1 km spatial resolution using remote sensing data and biome-specific statistical models. Different from the existing view that climate change dominated changes in Rs, we showed that land-cover change played a more important role in regulating Rs changes in temperate and boreal regions during 2000–2014. Significant changes in Rs occurred more frequently in areas with significant changes in short vegetation cover (i.e., all vegetation shorter than 5 m in height) than in areas with significant climate change. These results contribute to our understanding of global Rs patterns and highlight the importance of land-cover change in driving global and regional Rs changes.

Global soil microbial biomass decreases with aridity and land‐use intensification

2021 ◽  
Vol 30 (5) ◽  
pp. 1056-1069
Author(s):  
Xiaohua Wan ◽  
Xinli Chen ◽  
Zhiqun Huang ◽  
Han Y. H. Chen
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Soil Microbial ◽  
Land Use Intensification ◽  
Global Soil

scholarly journals Historical climate controls soil respiration responses to current soil moisture

2017 ◽  
Vol 114 (24) ◽  
pp. 6322-6327 ◽  
Author(s):  
Christine V. Hawkes ◽  
Bonnie G. Waring ◽  
Jennifer D. Rocca ◽  
Stephanie N. Kivlin
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Carbon Cycling ◽  
Large Scale ◽  
Microbial Respiration ◽  
Rainfall Gradient ◽  
Soil Microbial ◽  
Historical Climate ◽  
Moisture Dependence

Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40–70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil moisture, which remain unresolved in ecosystem models. A common assumption of large-scale models is that soil microorganisms respond to moisture in the same way, regardless of location or climate. Here, we show that soil respiration is constrained by historical climate. We find that historical rainfall controls both the moisture dependence and sensitivity of respiration. Moisture sensitivity, defined as the slope of respiration vs. moisture, increased fourfold across a 480-mm rainfall gradient, resulting in twofold greater carbon loss on average in historically wetter soils compared with historically drier soils. The respiration–moisture relationship was resistant to environmental change in field common gardens and field rainfall manipulations, supporting a persistent effect of historical climate on microbial respiration. Based on these results, predicting future carbon cycling with climate change will require an understanding of the spatial variation and temporal lags in microbial responses created by historical rainfall.

Sign in / Sign up

Export Citation Format

Share Document