scholarly journals Processing of grassland soil C-N compounds into soluble and volatile molecules is depth stratified and mediated by genomically novel bacteria and archaea

2018 ◽  
Author(s):  
Spencer Diamond ◽  
Peter Andeer ◽  
Zhou Li ◽  
Alex Crits-Christoph ◽  
David Burstein ◽  
...  
Keyword(s):  
Inorganic Nitrogen ◽  
Soil Microbial Activity ◽  
Grassland Soil ◽  
Soil C ◽  
C1 Metabolism ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Carbohydrate Degradation ◽  
Acetate Utilization ◽  
Shallow Soils

AbstractSoil microbial activity drives the carbon and nitrogen cycles and is an important determinant of atmospheric trace gas turnover, yet most soils are dominated by organisms with unknown metabolic capacities. Even Acidobacteria, among the most abundant bacteria in soil, remain poorly characterized, and functions across groups such as Verrucomicrobia, Gemmatimonadetes, Chloroflexi, Rokubacteria are understudied. Here, we resolved sixty metagenomic, and twenty proteomic datasets from a grassland soil ecosystem and recovered 793 near-complete microbial genomes from 18 phyla, representing around one third of all organisms detected. Importantly, this enabled extensive genomics-based metabolic predictions for these understudied communities. Acidobacteria from multiple previously unstudied classes have genomes that encode large enzyme complements for complex carbohydrate degradation. Alternatively, most organisms we detected encode carbohydrate esterases that strip readily accessible methyl and acetyl groups from polymers like pectin and xylan, forming methanol and acetate, the availability of which could explain high prevalences of C1 metabolism and acetate utilization in genomes. Organism abundances among samples collected at three soil depths and under natural and amended rainfall regimes indicate statistically higher associations of inorganic nitrogen metabolism and carbon degradation in deep and shallow soils, respectively. This partitioning decreased in samples under extended spring rainfall indicating long term climate alteration can affect both carbon and nitrogen cycling. Overall, by leveraging natural and experimental gradients with genome-resolved metabolic profiles, we link organisms lacking prior genomic characterization to specific roles in complex carbon, C1, nitrate, and ammonia transformations and constrain factors that impact their distributions in soil.

scholarly journals Forest defoliator pests alter carbon and nitrogen cycles

2016 ◽  
Vol 3 (10) ◽  
pp. 160361 ◽  
Author(s):  
Anne l-M-Arnold ◽  
Maren Grüning ◽  
Judy Simon ◽  
Annett-Barbara Reinhardt ◽  
Norbert Lamersdorf ◽  
...  
Keyword(s):  
Climate Change ◽  
Leaf Litter ◽  
Soil Microbial Activity ◽  
Quercus Petraea ◽  
Oak Forests ◽  
Operophtera Brumata ◽  
Winter Moth ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
C And N

Climate change may foster pest epidemics in forests, and thereby the fluxes of elements that are indicators of ecosystem functioning. We examined compounds of carbon (C) and nitrogen (N) in insect faeces, leaf litter, throughfall and analysed the soils of deciduous oak forests ( Quercus petraea  L.) that were heavily infested by the leaf herbivores winter moth ( Operophtera brumata  L.) and mottled umber ( Erannis defoliaria  L.). In infested forests, total net canopy-to-soil fluxes of C and N deriving from insect faeces, leaf litter and throughfall were 30- and 18-fold higher compared with uninfested oak forests, with 4333 kg C ha −1 and 319 kg N ha −1 , respectively, during a pest outbreak over 3 years. In infested forests, C and N levels in soil solutions were enhanced and C/N ratios in humus layers were reduced indicating an extended canopy-to-soil element pathway compared with the non-infested forests. In a microcosm incubation experiment, soil treatments with insect faeces showed 16-fold higher fluxes of carbon dioxide and 10-fold higher fluxes of dissolved organic carbon compared with soil treatments without added insect faeces (control). Thus, the deposition of high rates of nitrogen and rapidly decomposable carbon compounds in the course of forest pest epidemics appears to stimulate soil microbial activity (i.e. heterotrophic respiration), and therefore, may represent an important mechanism by which climate change can initiate a carbon cycle feedback.

scholarly journals Resilience of soil microbial activity and of amino acid dynamics to the removal of plant carbon inputs during winter

2009 ◽  
Vol 66 (1) ◽  
pp. 132-135 ◽  
Author(s):  
Elizabeth J. Avramides ◽  
Matina Christou ◽  
David L. Jones
Keyword(s):  
Amino Acid ◽  
Free Amino ◽  
Agricultural Soils ◽  
Soil Microbial Activity ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Heterotrophic Soil Respiration ◽  
Vineyard Soil ◽  
Labile C ◽  
Amino Acid Concentrations

Many temperate agricultural soils have prolonged periods in the winter when plant carbon inputs to the soil are low. Soil maintained at low temperature in the absence of plants was used to simulate the conditions in a vineyard soil during winter. In a four month simulated overwintering period we showed that the concentration of dissolved organic carbon and nitrogen in soil solution slowly declined alongside heterotrophic soil respiration. Measurements of free amino acid concentrations and turnover indicated that the amino acid pool in soil was rapidly depleted but readily replenished throughout the four-month period. This indicates that the soil contained intrinsic reserves of labile C that was capable of supporting the soil microbial community in times of reduced plant C inputs.

Energetic return on investment determines overall soil microbial activity.

2021 ◽  
Author(s):  
Louis Dufour ◽  
Anke Herrmann ◽  
Julie Leloup ◽  
Cédric Przybylski ◽  
Ludovic Foti ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Return On Investment ◽  
Metabolic Response ◽  
Soil Microbial Activity ◽  
Organic C ◽  
Soil C ◽  
Soil Microbial ◽  
C Dynamics ◽  
C Cycle ◽  
Energetic Analysis

Abstract Microbial communities are a critical component of the soil carbon (C) cycle, as they are responsible for the decomposition of both organic inputs from plants and of soil organic C. However, there is still no consensus about how to explicitly represent their role in terrestrial C cycling. We suggest that a full understanding of microbial communities’ involvement in soil C dynamics can only be attained when the interaction between the properties of both available organic C and microbial communities are accounted for. Here, we show that the potential energetic return on investment, derived from an energetic analysis of available organic C, is strongly related to the overall metabolic response of microbial decomposers. We further show that microbial communities do not all obtain the same energetic return on investment when metabolising the same organic C, suggesting that the response also depends on the intrinsic properties of the microbial communities.

scholarly journals MODELING OF THE CARBON AND NITROGEN CYCLES OF TUNDRA IN THE HOLOCENE

2020 ◽  
Vol 1 (5) ◽  
pp. 15-20
Author(s):  
M.M. Arzhanov ◽  
Keyword(s):  
Inorganic Nitrogen ◽  
Climatic Conditions ◽  
Near Surface ◽  
Soil C ◽  
Surface Warming ◽  
Carbon And Nitrogen ◽  
Annual Range ◽  
Northern Regions ◽  
Carbon And Nitrogen Dynamics ◽  
Tundra Ecosystems

The observed increase in near-surface temperature can cause degradation of permafrost and an increase in greenhouse gas emissions. At the same time, the productivity of the tundra increases, and more intense photosynthesis means an increase in the absorption of carbon from the atmosphere. Therefore, the development of models of the carbonnitrogen cycle to study the contribution of tundra ecosystems is a special challenge. In this work, the modeling of carbon and nitrogen dynamics in tundra ecosystems of northern regions of Western Siberia were carried out using the reservoirflow model including vegetation, organic carbon compounds, dissolved organic and inorganic nitrogen. Input data of the atmospheric forcing were set according to the results of calculations with CLIMBER-2 model for the last 10 thousand years. Model estimates show a regional increase in mean annual air temperature and a decrease in the annual range over a period of 10–5.5 thousand years ago due to an increase in winter temperatures in this region. According to the results of calculations, carbon stocks in soil increase monotonically during the period under consideration. Calculated soil C values for modern climatic conditions are 14700 gC/m2 . The reserves of nitrate and ammonium forms of nitrogen are stabilized at the beginning of the calculation period. The results of calculations show that tundra ecosystems within the last 10 thousand years, including those under conditions of near-surface warming with increasing winter temperature and minor changes in summer temperature could accumulate organic matter, absorbing carbon-containing greenhouse gases from the atmosphere.

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

<p>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.</p><p>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, β-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.</p><p>Acknowledgments: to the Spanish MICINN (MINECO, AEI, FEDER, EU) for supporting the research projects AGL2016-75762-R and CGL2015-65162-R.</p>

scholarly journals Effect of Plant Growth Regulators on Protease Activity in Forest Floor of Norway Spruce Stand

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 665
Author(s):  
Ladislav Holik ◽  
Jiří Volánek ◽  
Valerie Vranová
Keyword(s):  
Organic Matter ◽  
Proteolytic Activity ◽  
Protease Activity ◽  
Forest Floor ◽  
Soil Microbial Activity ◽  
Inhibitory Effects ◽  
Chlorocholine Chloride ◽  
Soil Microbial ◽  
Native Soil ◽  
Transformation Processes

Soil proteases are involved in organic matter transformation processes and, thus, influence ecosystem nutrient turnovers. Phytohormones, similarly to proteases, are synthesized and secreted into soil by fungi and microorganisms, and regulate plant rhizosphere activity. The aim of this study was to determine the effect of auxins, cytokinins, ethephon, and chlorocholine chloride on spruce forest floor protease activity. It was concluded that the presence of auxins stimulated native proteolytic activity, specifically synthetic auxin 2-naphthoxyacetic acid (16% increase at added quantity of 5 μg) and naturally occurring indole-3-acetic acid (18%, 5 μg). On the contrary, cytokinins, ethephon and chlorocholine chloride inhibited native soil protease activity, where ethephon (36% decrease at 50 μg) and chlorocholine chloride (34%, 100 μg) showed the highest inhibitory effects. It was concluded that negative phytohormonal effects on native proteolytic activity may slow down organic matter decomposition rates and hence complicate plant nutrition. The study enhances the understanding of rhizosphere exudate effects on soil microbial activity and soil nitrogen cycle.

scholarly journals Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
A. Marais ◽  
M. Hardy ◽  
M. Booyse ◽  
A. Botha
Keyword(s):  
Soil Moisture ◽  
Microbial Communities ◽  
Crop Rotation ◽  
Management Practices ◽  
Agricultural Soils ◽  
Soil Microbial Communities ◽  
Soil Microbial Activity ◽  
Most Probable Number ◽  
Probable Number ◽  
Soil Microbial

Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.

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