Differential effects of altered precipitation regimes on soil carbon cycles in arid vs . humid terrestrial ecosystems

2021 ◽  
Author(s):  
Bin Wang ◽  
Yali Chen ◽  
Yan Li ◽  
Hui Zhang ◽  
Kai Yue ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Terrestrial Ecosystems ◽  
Differential Effects ◽  
Carbon Cycles ◽  
Altered Precipitation ◽  
Precipitation Regimes

scholarly journals Active communities and growth of soil microorganisms are framed by mean annual precipitation in three California annual grasslands

2021 ◽  
Author(s):  
Megan M. Foley ◽  
Steven J. Blazewicz ◽  
Karis J. McFarlane ◽  
Alex Greenlon ◽  
Michaela Hayer ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Growth Rates ◽  
Strong Predictor ◽  
Soil Microbial Communities ◽  
Stable Isotope Probing ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
Wet Season ◽  
Altered Precipitation ◽  
Precipitation Regimes

AbstractEarth system models project altered precipitation regimes across much of the globe. In California, the winter wet season is predicted to extend into spring, and the summer dry period to lengthen. How altered precipitation will affect soil carbon (C) persistence is a key knowledge gap. However, we do not have a mechanistic understanding of how altered soil moisture regimes will affect microbial population dynamics. Using quantitative stable isotope probing (qSIP), we compared total and active soil microbial communities across three California annual grassland ecosystems that span a rainfall gradient and have developed upon similar parent material. We also assessed multiple edaphic variables, including available C and the radiocarbon (14C) age of soil C. Samples were assayed in the wet season, when we expected environmental conditions would be most similar across sites. We hypothesized that the long-term legacy of soil water limitation would be reflected in lower community growth capacity at the driest site. We also predicted that actively growing communities would be more compositionally similar across the gradient than the total background microbiome. Across the three sites, edaphic parameters such as pH roughly sorted with mean annual precipitation, and soil carbon age increased with precipitation. Bacterial growth rates increased from the driest site to the intermediate site, and rates were comparable between the intermediate and wettest sites. These differences were persistent across major phyla, including the Actinobacteria, Bacteroidetes, and Proteobacteria. Taxonomic identity was a strong predictor of growth, such that the growth rates of a taxon at one site predicted its growth rates at the others. We think this fact, that taxa that grew quickly at one site tended to grow quickly at the others, is likely a consequence of genetically determined physiological traits, and is consistent with the idea that evolutionary history influences growth rate.

scholarly journals Linking Genes to Traits in Fungi

2021 ◽  
Author(s):  
A. L. Romero-Olivares ◽  
E. W. Morrison ◽  
A. Pringle ◽  
S. D. Frey
Keyword(s):  
Organic Matter ◽  
Nitrogen Uptake ◽  
Brown Rot ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Gene Frequencies ◽  
Ecological Processes ◽  
Linked Gene ◽  
Carbon Cycles ◽  
Brown Rot Fungi

AbstractFungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

scholarly journals Changes in Soil Carbon Sequestration during Woody Plant Encroachment in Arid Ecosystems

2021 ◽  
Vol 4 (4-5) ◽  
pp. 266-276
Author(s):  
Pratap Naikwade
Keyword(s):  
Climate Change ◽  
Carbon Sequestration ◽  
Soil Carbon ◽  
Atmospheric Carbon Dioxide ◽  
Global Climate ◽  
Terrestrial Ecosystems ◽  
Greenhouse Gas Mitigation ◽  
Arid Ecosystems ◽  
Woody Encroachment ◽  
Organic C

Carbon sequestration is one of the most important and highly recommended measures for mitigating climate change. Soil organic carbon (SOC) has potential to sequester the largest amount of carbon (C) for the longest time period in the midst of the organic C sinks in terrestrial ecosystems of the earth. In recent years, apprehension of the role of soils as sink for carbon on a wide-ranging scale has become dynamic. From last 150 years, encroachment of trees and shrubs into grasslands and the ‘thicketization’ of savannas have been reported and is a global phenomenon. One possibly beneficial effect could be that the shrub and tree-dominated ecosystems will sequester more carbon and will be a buffer for elevated atmospheric carbon dioxide (CO2) levels. The question of what is impact of woody encroachment on soil carbon balance of an ecosystem has proved difficult to answer, and the results remain debatable. The magnitude and pattern of changes in the SOC with woody encroachment are exceedingly abstruse and varies from significant increases, to significant decreases to no net change in SOC. Impact of wood plant encroachment on carbon sequestration is discussed in this paper considering various studies with different results so it will lead to better understanding of the complex phenomenon. SOC sequestration is effective greenhouse gas mitigation strategy and a vital ecosystem service. Increasing SOC may helpful to mitigate negative effects of growing concentration of CO2 in atmosphere and may be advantageous in decelerating or reversal in global climate change rate.

scholarly journals Is the Change of Soil Carbon Capacity Persistence Rising or Remain Stable With Maturity of Vegetation Restoration?

2021 ◽  
Vol 1 ◽  
Author(s):  
Qian Liu ◽  
Peipei Wang ◽  
Zhijing Xue ◽  
Zhengchao Zhou ◽  
Jun'e Liu ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Carbon ◽  
Ecological Restoration ◽  
Carbon Sink ◽  
Early Stage ◽  
Terrestrial Ecosystems ◽  
Vegetation Restoration ◽  
Land Use Types ◽  
Soc Stock

Emerging consensus is that land-use change resulting through the “Grain for Green” project has had a significant impacted on soil organic carbon (SOC), thereby probably enhancing the carbon sequestration capacity of terrestrial ecosystems. However, it remains largely unknown whether a watershed acts as a source or sink of soil carbon during the later period of ecological restoration. This study comprehensively investigated the changes of SOC stock in 2005, 2010, and 2017 along different land-use types. It was aimed to evaluate the dynamics to SOC storage capacity over different vegetation restoration maturity in the Shanghuang Watershed, China. The results showed that restoration increased the accumulation of organic carbon pools in the early stage. Significant increases in SOC stock were observed in shrubland and grassland in comparison to that in other land uses, and these two land-use types represented the optimal combination for ecological restoration in the basin. The SOC stock did not increase indefinitely during the long-term vegetation restoration process, but rather first increased rapidly with vegetation planting and reached a peak, following which it declined slightly. Therefore, pure vegetation restoration cannot maintain a permanent soil carbon sink, some measures to maintain the stability of carbon and to prolong soil C persistence are essential to take.

scholarly journals Divergent responses of biomass accumulation and its allocation to the altered precipitation regimes among different degraded grasslands in China

2021 ◽  
Author(s):  
Tianxue Yang ◽  
Junda Chen ◽  
Xiaoyue Zhong ◽  
Xuechen Yang ◽  
Gui Wang ◽  
...  
Keyword(s):  
Climate Models ◽  
Plant Biomass ◽  
Inorganic Nitrogen ◽  
Precipitation Amount ◽  
Soil Layer ◽  
Ecosystem Functions ◽  
Precipitation Frequency ◽  
Positive Effects ◽  
Altered Precipitation ◽  
Precipitation Regimes

Abstract Purpose Climate models predict shifts in precipitation patterns characterized by increased precipitation amount and decreased frequency for semi-arid grasslands in northeast China. However, under these novel climatic conditions, potential differences in plant biomass and its allocation among different degraded grasslands remain unclear.Methods We conducted a mesocosm experiment to test the effects of higher precipitation amount (increased by 50% from the long-term mean) and lower frequency (decreased by 50%) on plant biomass and allocation in the lightly degraded (LDG), moderately degraded (MDG), and severely degraded grasslands (SDG).Results Lower precipitation frequency promoted belowground biomass (BGB), while reducing aboveground biomass (AGB) allocation through enhancing soil water variability. Higher precipitation amount enhanced AGB in LDG and MDG, but not in SDG due to less soil inorganic nitrogen. Lower precipitation frequency weakened the positive effects of higher precipitation amount on biomass. Under altered precipitation, adjustment of AGB vs. BGB allocation was the primary biomass allocation strategy in LDG and SDG. However, to maintain water acquirement, plants in MDG preferred to adjust root vertical distribution, and allocated more roots to the deep soil layer where had a relatively stable water source. This strategy was driven by the changes in plant community composition of the dominant species in MDG.Conclusions The findings of this research emphasized the importance of considering the degradation level of grasslands when predicting the responses of the ecosystem functions to the projected changes in precipitation regime. These findings are critical for making feasible decisions for the sustainable management of degraded grasslands.

scholarly journals Decadal-scale shifts in soil hydraulic properties as induced by altered precipitation

2019 ◽  
Vol 5 (9) ◽  
pp. eaau6635 ◽  
Author(s):  
Joshua S. Caplan ◽  
Daniel Giménez ◽  
Daniel R. Hirmas ◽  
Nathaniel A. Brunsell ◽  
John M. Blair ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Terrestrial Ecosystems ◽  
Soil Hydraulic Properties ◽  
Infiltration Rates ◽  
Precipitation Regimes ◽  
Decadal Scale ◽  
Pore Blockage ◽  
Plant Available Water ◽  
Soil Hydraulic ◽  
Precipitation Manipulation Experiment

Soil hydraulic properties influence the partitioning of rainfall into infiltration versus runoff, determine plant-available water, and constrain evapotranspiration. Although rapid changes in soil hydraulic properties from direct human disturbance are well documented, climate change may also induce such shifts on decadal time scales. Using soils from a 25-year precipitation manipulation experiment, we found that a 35% increase in water inputs substantially reduced infiltration rates and modestly increased water retention. We posit that these shifts were catalyzed by greater pore blockage by plant roots and reduced shrink-swell cycles. Given that precipitation regimes are expected to change at accelerating rates globally, shifts in soil structure could occur over broad regions more rapidly than expected and thus alter water storage and movement in numerous terrestrial ecosystems.

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