# Effect of climate change on soil microorganism in perspective of living soils and plant-microbe interaction

Ajeet Kumar, Anil Kumar Singh

► To cite this version:

Ajeet Kumar, Anil Kumar Singh. Effect of climate change on soil microorganism in perspective of living soils and plant-microbe interaction. Agriculture and Climate Change-Impacts and Solutions, 2022, pp.89-101. hal-04881411

HAL Id: hal-04881411

https://hal.science/hal-04881411v1

Submitted on 12 Jan 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

# Effect of Climate Change On Soil Microorganism in Perspective of Living Soils and Plant-Microbe Interaction

Ajeet Kumar and Anil Kumar Singh

## 1. Introduction

Communities of soil microorganisms play a major role in biogeochemical cycles that support the plant growth. Here we focus primarily on the roles that the soil micro-biome plays in cycling soil organic carbon and the impact of climate change on the soil. Climate change is altering the distributions of microbial species and thus interactions among organisms above and below soil. The wealth of biodiversity below ground is vast and unappreciated; millions of microorganisms live and reproduce in few gram of topsoil, an ecosystem essential for life on earth. Organisms live in concert with thousands of other species out of which, some are beneficial, some are pathogenic and some have little or no effect in complex communities. The natural communities are composed of organisms with different traits and dispersal ability. It is all respond to climatic change in a similar way. Disjuncts in plant-pollinator and plant-herbivorous interactions under climate change have been described, but plant-soil microorganism and soil microbe-microbe relationships have received less attention. Since soil microorganisms regulate nutrient transformations, which provide nutrients to growing plants, and allow co-existence among neighbour, and
control plant populations, changes in soil microorganism and plant interactions have significant ramifications for plant community composition and ecosystem function. Soil microorganisms also play essential roles in the nutrient cycles that are fundamentally important to life on the planet. In this chapter, an attempt has been taken to explore how climatic change affects soil microbes and soil microbe-plant interactions directly and indirectly.

The change in climate is altering species distributions and simultaneously impacting interactions among organisms. Natural communities are composed of organisms with different traits, thermal tolerances, and dispersal ability. Among microbial community, the interactions may be beneficial, pathogenic, or have little or no functional impact and these interactions may change with environmental stress. The shifts in species interactions in response to climate change cascade to alter biodiversity and the function of terrestrial ecosystems. Soil organisms and plants interact with one another in several ways that maintain ecosystem properties. In fact, soil microbial interactions, with each other as well as with plants, can shape landscape patterns of plant and animal abundance, diversity, and composition. Plant-microbial interactions are considered negative when the net effects of all soil organisms—including pathogens, symbiotic mutualists, and decomposers—reduce plant performance, while interactions are considered positive when the benefits brought by the soil microbial community enhance plant performance like as biomass production and survival. Therefore, given their importance in defining ecosystem properties, understanding how soil microbe-microbe and soil microbe-plant interactions respond to climate change.

The 120 Gt yearly flux of carbon into and out of terrestrial ecosystems far exceeds the amount of carbon that is being produced by the combustion of fossil fuels (IPCC 2013). Thus, a small change in the amount of carbon an ecosystem exchanges with the atmosphere has a large impact on future concentrations of atmospheric carbon. Ecosystem models have considerable uncertainty regarding surrounding carbon to the atmosphere from terrestrial ecosystems. Much research has, therefore, focused on how to generate more reliable predictions of carbon fluxes with the goal of estimating how much carbon can be stored in terrestrial ecosystems. Soils in combination with plant biomass hold 2.53 more carbon than the atmosphere (Singh, 2010). Soils have the capacity to retain large amounts of carbon and their ability to sequester carbon has helped to mitigate rising atmospheric CO₂ level. Several factors regulate the amount of soils carbon can sequester including climate, parent material, age and texture of the soil, topography, vegetation type, and composition of the soil community (Jenny, 1941). Microbial decomposers ultimately regulate the rate of decomposition process and thus they influence the abiotic factors on decomposition. Yet, how microbial activity will influence carbon feedbacks among plants, soil, and the atmosphere is uncertain (Verheijen et al. 2015). If the decomposition rate increases relative to inputs
coming from plants and animals then the amount of carbon in soil will decrease as carbon enters in the atmosphere, which may enhance carbon-climate feedbacks (Wiederet al. 2013). In addition to the direct control over the decomposition process, microbial communities can influence important plant properties such as productivity and litter quality, properties that regulate fluxes in the carbon cycle. The microbial activity plays vital role in future terrestrial carbon feedbacks, however the current understanding of climate effects on microbe-microbe or plant-microbe interactions remains tottering. Here, we explore how climate change affects soil microbe-microbe and plant-microbe interactions as well as some of the ramifications shifts in these interactions have for the composition and function of ecosystems. The microbes have the potential to mediate important processes of microbial transformation of nutrients and others such as plant chemistry and plant community composition.

## 2. Current Challenges

The ecosystems within soil are highly complex and subject to different landscape-scale dither that regulate the soil carbon. The ultimate fate of Soil Organic Carbon (SOC) is a function of the combined activities of plants and belowground organisms, including soil microbes. Although soil microorganisms are known to support a plethora of biogeochemical functions related to carbon cycling, the majority of the soil microbiome remains uncultivated and has largely cryptic functions. Only a mere fraction of soil microbs has been catalogued to date, although new soil microbes and viruses are increasingly being discovered. The lack of knowledge results in uncertainty of the contribution of soil microorganisms to SOC and hinders construction of accurate predictive models for global carbon flux under climate change. Plant-derived carbon inputs can prime microbial activity to decompose existing SOC at rates higher than model expectations. A conceptual model known as the microbial carbon pump has been developed to define how soil microorganisms transform and stabilize soil organic matter. In this model, the metabolic activities of microbes for carbon turnover are divided in two categories: *ex vivo* modification, means the transformation of plant-derived carbon by extracellular enzymes, and *in vivo* turnover, the intracellular carbon used in microbial biomass formation turnover or deposited as dead microbial biomass, referred as necromass. The contrasting impacts of catabolic activities that release SOC as carbon dioxide, versus anabolic pathways that produce stable carbon compounds, control net carbon retention rates. In particular, the carbon sequestration did by microbes represents an under represented aspect of carbon flux in the soil. Plant-derived carbon enhances microbial SOC storage or alternatively accelerates SOC decomposition. For example, the needle litter leaf and litter serve as carbon sources for microbial growth in the soils of forest, but the chemistry of litter and pH varies as per vegetation type e.g., between root and foliar litter or between deciduous and coniferous forest litter. In turn, these biochemical differences influence SOC levels through changing decomposition dynamics. Also, increased diversity of plant
communities increases rates of rhizo-deposition, stimulating microbial activity and SOC storage, although soils eventually reach a saturation point beyond which they cannot store additional carbon.

Quiescence also impacts microbial metabolic rates. Quiescence is the reversible state of a cell in which it does not divide but retains the potential ability to re-enter in cell proliferation. Many soil microorganisms are transiently active, alternating between dormant and active states. During dormancy, some microorganisms inhibiting in the soil are capable of utilizing their energy reserves to metabolize soil organic carbon and contribute to soil biomass turnover, albeit at slower rates. Nevertheless, active members of the soil community contribute to biogeochemical transformations, and a new paradigm is to shift analyses away from taxonomic profiles and toward microbiome functional pathways and phenotypes.

The current technology for sequencing of microbial community composition also measure dormant microorganisms and even exogenous DNA. Refining approaches to focus on function to aid model construction through accurate assessment of real processes. Another challenge is accounting the chemistry of soil and physical structure of soil, both of which influence the decomposition of soil organic carbon. Traditionally, slow rate of carbon turnover was thought to be attributable to physical protection of carbon molecules in micro-aggregates or mineral associations or to their chemical recalcitrance to biodegradation. The current paradigm expands on soil mineral associations through soil particles, sorption of biopolymers from microbial community and plant necromass. Indeed, deep soil organic matter is mainly comprised of microbe-derived products. Additionally, the spatiotemporal structure of soils is heterogeneous and dynamic, with "hot spots" or "hot moments" of microbial activity. For instance, water availability is typically uneven, so carbon cycling is limited to areas with sufficient water, or to microbes capable of dealing with desiccation stress e.g., through production of extracellular polymeric substances to maintain a hydrated microenvironment. In addition, other factors influencing the mineralization of soil organic carbon include presence of aerobic microsites versus anaerobic (anaerobic respiration of carbon is less favourable than aerobic), availability of electron acceptors, and redox status of the soil. Carbon profiles also matter: For example, carbon compounds recalcitrant to anaerobic degradation (e.g., lipids) are preferentially retained in anaerobic aggregates. Therefore, comparisons of soil organic carbon decomposition profiles across different types of soil and the structures are necessary for better understanding of soil microbial metabolism and carbon flux.

### 3. Soil microbial communities and plants directly influenced by climatic change

Climatic change alters the relative abundance and function of soil microbial communities. The members of soil microbial community differ in their physiology,
temperature sensitivity, and growth rates (Whitaker *et al.* 2014). Warming by 5°C in a temperate forest, for example, altered the relative abundances of soil bacteria and increased the bacterial to fungal ratio of the community (DeAngelis *et al.* 2015). The communities of microbes well respond to warming and other perturbations through resistance, enabled by microbial plasticity, or resilience as the community returns to an initial composition after the stress has passed (Allison and Martiny 2008). The shifts in composition of microbial community are likely to changes in function of ecosystem when soil organisms differ in their traits or control a fate-controlling or rate-limiting step. For instance, specific microbial groups regulate the functions of ecosystem such as nitrogen fixation, nitrification, denitrification, and methanogenesis. Change in the relative abundance of organisms that regulate specific processes can have a direct impact on the rate of governing all the processes. However, some processes occur at coarser scale, such as mineralization of nitrogen, are correlated with abiotic factors like temperature and moisture than microbial community composition because a diversity of organisms drives this processes (Hooper, 2005). Global changes such as rise in temperature or warming up are directly altering the microbial soil respiration rates because soil microorganisms and the processes they mediate, are temperature sensitive. The role of elevated temperature in microbial metabolism has considerable impact. Karhu, 2014 reported that no changes in community composition occurs, the intrinsic temperature sensitivity of microbial activity is defined as the factor by which microbial activity increases with a 10°C increase in temperature (Q₁₀).

Q₁₀ is used in climate change models to account for temperature sensitivity of microbial communities; however using this relationship masks many interactions that influence the temperature sensitivity of microbial processes such as decomposition. Therefore, using only Q₁₀ to account for temperature sensitivity may lead to poor predictions. Further, while decomposition of soil organic matter, soil respiration, and growth of microbial biomass generally increase with temperature, these responses to experimental warming are often short-lived in field studies (Bradford et al. 2008). The transitory effects of warming on soil microbial communities have been hypothesized to occur as soil carbon substrates are depleted by increased microbial activity and because of trade-offs as microbial communities either acclimate, shift in composition, or constrain their biomass to respond to altered conditions and substrate availability. Experimental warming can initially alter the composition of microbial communities, and shift the abundance of gram-positive and gram-negative bacteria (Zogg et al. 1997), or warming effects may take many years before a response is evident within the microbial community.

The direct effects of temperature on microbial physiology are complex and likely mediated by microbial adaptations, evolution, and interactions over time. Temperature changes are often coupled with changes in soil moisture, which may explain some inconsistent results from experiments exploring how microbial communities respond to climatic change. For example, rates of microbial activity at warmer temperatures
can be limited by diffusion and microbial contact with available substrate (Zak et al. 1999). While bacterial communities respond rapidly to moisture pulses, the slower-growing fungal community may lag in their response (Cregger et al. 2014). Further, drought amplifies the differential temperature sensitivity of fungal and bacterial groups. Even with small changes in soil moisture availability (30% reduction in water holding capacity), soil fungal communities' shift from one dominant member to another while bacterial communities remain constant. These patterns indicate greater fungal plasticity than bacterial plasticity during non-extreme wet-dry cycles. Soil communities adapted to low water availability or repeated wet-dry cycles may elicit less of a compositional or functional shift to changing water regimes. Interactions among microbes and background temperature and moisture regimes in any location influence microbial composition and function with change inclimate.

## 4. Impacts of Climate change on plant-microbes interactions

With rise in temperature, plant species are migrating to higher elevations and leafing out and flowering earlier in the growing season, and are altering the functional trait expression. Scaling up to the community level, warming has resulted in shrubification of the arctic as woody shrubs have replaced grasses and forbs in several regions leading to changes in ecosystem properties and carbon feedbacks in these systems. Soil communities especially communities that are tightly coupled with plants, may be facilitating or retarding plant community transitions.

Root-associated microbial communities have a strong influence on plant survival, phenology and expression of functional traits. All traits are responding to climate changes. The importance of interactions among plants, their associated microbial community and change in climate on functions of ecosystem are poorly understood. Shifts in the bulk soil microbial community induced by climate change have long lasting effects on plant performance and establishment and soil carbon balance. In fact, the interactions between plants and soil communities, such as plant-soil the most important soil nitrogen and carbon dynamics. If climate change alters soil microbial communities and this change determines establishment of plant species and their growth, then ecosystem responses will be contingent on the interactions between plants and soil communities. Studies suggest that rapid responses of the surrounding soil microbial community can buffer plants to drought stress. Evidence suggests that changes in microbial diversity can alter selection on plant functional traits. The indirect impacts of climate on plants and their associated soil microbial communities differ from the direct effects of climate on the bulk of soil microbial community.

The changes in precipitation altered the community of soil microbes and its function but the effect of precipitation on composition and function of soil microbial community varied from plant to plant and from soil to soil. Further, soils that were collected across the site and homogenized to assess the impact of climate change
on communities and functions showed a relatively muted response. The results suggest that responses of soil ecosystem towards climate changes could be offset if plant microbial community composition shifts with climate change. Therefore, these community and functional shifts may be underrepresented in most studies because soils are collected across plant species and homogenized together. The interaction between plants and their associated soil microbial communities, may build up in the soil system and influences ecosystem function e.g., cycling of carbon and plant establishment over time. **Mineralization:** conversion of an element (e.g., carbon or nitrogen) from an organic to an inorganic form, for example when organic carbon is converted to carbon dioxide and inorganic nutrients through microbial metabolism, is called mineralization. **Resistance:** the capacity of a micro-biome to retain a consistent community and functional composition in the face of an external perturbation, is called resistance. **Resilience:** the capacity of a micro-biome to recover to an initial stable state after cessation of an external perturbation, is called resilience.

# 5. Indirect influence of climatic change on soil microbial communities and plant

## 5.1 Climate change alters plant and microbial distribution

Migrations of plant species in response to climate change are well noticed. The most studies fail to address the ability of associated soil micro-organisms to shift their range to maintain the positive or negative relationship between the plant and the soil community. Soil biota may respond to climate change at a different rate in comparison to the plants biota. The differential dispersal abilities between plant and microbe may alter plant establishment and plant productivity as well as the interactions among plants in a community. Expanding plant species are better defended against aboveground herbivores and develop less pathogenic activity in soils compared to their related natives in the new range. If plants that successfully establish in new ranges have higher induced levels of plant defence compounds such as polyphenols, then litter input quality will decline and the decomposer community will shift in composition or activity. It is still relatively unknown that how the disconnected geographic migration of plants and microbes will impact the establishment of plants in new environments, the literature on plant invasion indicates that lack of ectomycorrhizal fungi can stop or slow pine invasions.

The geographic disconnects might influence the composition and functioning of soil microbial community. The limitation of microbial dispersal could scale to impact coarse-scale processes such as decomposition and nutrient mineralization. The rate at which isolated communities of microbes are able to adapt towards climate change is unknown. The plant and soil reciprocal across transitional areas such as tree lines or ecotonal boundaries are vital issues. Ecotone, a transitional area of vegetation between two different plant communities, such as forest and grassland. An ecotonal
area has a higher organisms density of one species and a greater number of species than are found in either flanking community. Relative to aboveground plant structures, soils are buffered to changes in temperature, precipitation and possibly to extreme events like frost, droughts etc. Below ground microbial communities are, therefore, structured by different environmental conditions than above ground communities and constrained by different characteristics. For this reason, the direct environmental pressures, plants are experiencing under climate change may be different from their associated soil community is experiencing. Microbial communities clearly respond to both biotic and abiotic drivers, but the indirect effects of climate change, mediated by plant community shifts, which counteract or be different than the direct effects. Soil communities respond to climate stress by changing their distribution in the soil profile. For example, soil microorganism move down in the soil profile if temperatures at the surface are outside of their thermal optimum range. Re-sorting of soil communities, and thus interactions, in the soil profile may further alter plant-microbe-process interactions. However, the extent of change in the direct or the indirect effects of climate change on microbe-microbe or plant-microbe interactions are relevant for ecosystem, is still unknown. Decoupling of plant and microbial community responses to the same environmental drivers using experimental (reciprocal transplants) and observational (elevational and environmental gradients) approaches.

## 5.2 Plant phenology and microbial communities

Phenology is the study of periodic events in biological life cycles as these are influenced by seasonal and inter-annual variations in climate. Climate change alters plant phenology, which eventually alters microbial communities. The change in climate greatly influences the root phenology and subsequent plant-rhizosphere interactions. These processes are less explored in phenological studies. If root growth peaks early in the growing season, above ground and below ground phenologies can be synchronous. However, root and shoot phenologies are commonly asynchronous, shoot phenology may not always be a reliable predictor of plant response to climate change. Root phenology varies by species and among ecosystems because it is driven by complex interactions between abiotic factors (temperature and moisture) as well as stored plant carbon and nutrient. Durations of growing season are increasing under climate change (IPCC 2013). Therefore, successive peaks across the growing season in root, foliar and mycorrhizal biomass may become asynchronous, leading to changes in nutrient and carbon fluxes. The change in root-shoot phenology will influence the impact of rhizosphere interactions that may influence the distinct seasonal assemblages of soil microbial groups. The relationship among photoperiod, temperature, and soil moisture becomes asynchronous with climate change, then root, shoot, and microbial phenologies may also become asynchronous. These interactions may drive plant community shifts and affect ecosystem productivity under climate change.
# 6. Impact of climate change on plant-microbe interactions

Bacteria and fungi have close associations with plant roots. These associations may alter the expression of plant traits such as leaf area and nutrient content. Root symbionts such as rhizobia bacteria and mycorrhizal fungi affect plant productivity by altering plant nutrient status. The impact of specific strains of rhizobia on other plant traits may be equally important under changing climatic scenario. When a common rhizobia strain present in nitrogen-fixing mutualisms, plant specific leaf area and carbon assimilation rate increased. Mycorrhizal fungi associate with nearly all terrestrial plants (Brundrett 2002) and are important players in carbon and nutrient-cycling processes. Similar to rhizobia, mycorrhizal fungi exchange nutrients for plant carbon, thus influencing plant carbon to nutrient ratios and eventually plant productivity. Consequently, mycorrhizal fungi affect decomposition activity within the soil microbial community by altering the quality of plant litter as well as carbon inputs (Moore et al. 2015). Specific mycorrhizal strains can alter plant reproduction, tiller production, root biomass production, rooting depth, and herbivory rates. However, the interactions between mycorrhizal strain identity and host plant are not always symbiotic, it may change with environmental factors or even plant stress. The composition of Mycorrhizal community can change with temperature. Current knowledge for climate change and the direction of plant-root microbe interactions from positive to negative or vice versa and climatic change interactions between plants and their myriad of symbionts in tandem, possibly having additive effects on ecosystem.

## 6.1 Climate change influences microbe-microbe interactions

Microbes form complex network of interactions that are continually responding to climate changes. Mycorrhizal fungi foraging can alter free-living bacterial communities in ways that vary nitrogen transfer from the mycorrhizae to the plant as well as decomposition of organic matter. The rise in temperatures lead to increased carbon allocation to mycorrhizal hyphae, which may swing the mycorrhizal association from symbiotic to parasitic. Shifts in these mycorrhizal-plant interactions can cascade to alter the soil microbial composition and activity in ways that may exacerbate the negative or positive interaction between the plant and its associated community. Other interactions between fungi and bacteria in the free living community are likely to modify ecosystem functions and carbon feedbacks. Microbial organisms and communities live and interact in relatively small soil structures, have short life spans, and the majority of individuals may be dormant at any point in time. It is difficult to determine the abundance of active groups in the community across ecosystems. They vary according to type of vegetation, soil type or climate. This approach leads to predict microbe-microbe and microbe-plant interactions, in ecosystem response to climate change.
## 6.2 Scaling plant-microbe interactions

Soil microbial communities are diverse and perform numerous functions. Although changes in microbial diversity at fine scale may not alter certain ecosystem processes, they may at coarse scale. Soil microbial communities are primarily composed of bacterial and fungal groups and these groups have varied functions in the decomposition process. In general, bacterial quickly decomposes labile substrates, while fungal decomposition at slower rate and target more complex organic materials. Soil microbes, particularly fungi, play important roles in altering soil structure such as aggregate formation, which can alter the processes of carbon transformation. Changes in the composition and function of soil fungi and bacteria are thus expected to affect soil carbon storage. Microbial communities operate at very small spatial and temporal scales, where entire communities may be limited to a single soil particle or soil aggregate and can turn over under an hour. However scientists measure microbial communities across meta-communities a single soil core, at the individual plant-level or the ecosystem level. Thus microbial interactions and processes from the cell or soil particle to the ecosystem is a significant challenge. The matrix of soil have heterogeneous environment and there may be nutrient and moisture oases that promote hotspots of microbial activity and potentially selected for microbes that may take advantage of resources. Soil aggregates can protect microbes from extreme conditions in the external environment and contain water and nutritional resources. Microbial functions, such as production of enzyme and availability of substrate, may vary through the soil matrix. Variation in composition of microbial community through the soil profile can affect microbial interactions with plant roots such as competition for nitrogen.

Soil microbes are essential for the maintenance of biodiversity above and below ground. The wealth of biodiversity below ground is massive. Millions of microorganisms live and reproduce in a few grams of topsoil. The top soil is an ecosystem essential for life on earth. Soil fertility comprises three interrelated components i.e. physical, chemical and biological fertility. The organisms that live in the soil and interact with the other components, varies greatly depending upon conditions and it is highly complex and dynamic. The soil microorganisms play important roles in the nutrient cycles that are fundamental to life on the planet. Fertile soils teem with soil microbes. There may be millions to billions of microbes in a single gram of soil. The larger number of microbes in soil is the bacteria, followed in decreasing numerical order by the actinomycetes, the fungi, soil algae and soil protozoa. The understanding of soil microbiology is essential if agricultural production is to meet the demand of a growing population. In many areas, the healthy microbe population is still being threatened and not promoted by agricultural practices.

Soil fertility is capacity to enrich natural and agricultural plants, is dependent upon three mutually dependent components viz. physical, chemical and biological
fertility. Physical properties of soil, includes its structure, texture and water absorption and holding capacity and root penetration. Chemical fertility involves nutrient levels and the presence of chemical attributes such as acidity, alkalinity and salinity that may be harmful or toxic to the plant. Biological fertility refers to the organisms that live in the soil and interact themself with other components also. Organisms live on soil, organic matter or other soil organisms and perform many essential processes in the soil, some of them perform critical functions in the carbon and nutrient cycles. Very few soil organisms are pests. Among all the three fertility components, it is the microbiological element, that are rich in diversity of organisms like bacteria, fungi, algae and viruses that form interactive microbial communities that are the most complex and, paradoxically, the least well-understood. The understanding of soil microbial communities as important as mapping the galaxies in the universe or the biodiversity of the oceans. It provides an opportunity to discover current species. The soil microbial communities underpin the productivity of agricultural enterprises and are primary drivers in ecological processes such as the nutrient and carbon cycling, degradation of pollutants and suppression of soil-borne diseases. They are also intimately involved in a range of beneficial and, at times essential, interrelationships with plants.

**7. Conclusions**

A recent activities emphasized the importance of microorganisms with reference to climate change. Abundant evidence reveals that soil microbes are affected by climate change under associated disturbances with important ecosystem, soil health and climate forcing situation. Under these disturbances, shifts in microbial community composition and function will in turn have repercussions for inter kingdom interactions, biogeochemical cycling and carbon flow, in ways that may exacerbate or attenuate climate change. In order to fully understand the key roles carried out by microorganisms inhabiting soil ecosystems, used to predict how critical metabolic processes are impacted by environmental change, and further more may be leveraged for mitigation of negative aspects of climate change.
References

Allison, S. D. and J. B. H. Martiny. 2008. Resistance, resilience and redundancy in microbial communities. *Proceedings of the National Academy of Sciences USA* 105:11512-11519.

Bradford, M. A., C. A. Davies, S. D. Frey, T. R. Maddox, J. M. Melillo, J. E. Mohan, J. F. Reynolds, K. K. Treseder, and M. D. Wallenstein. 2008. Thermal adaptation of soil microbial respiration to elevated temperature. *Ecology Letters* 11:1316-1327.

Brundrett, M. C. 2002. Coevolution of roots and mycorrhizas of land plants. *New Phytologist* 154:275-304.

DeAngelis, K. M., G. Pold, B. D. Topcuoglu, L. T. A. van Diepen, R. M. Varney, J. L. Blanchard, J. Melillo, and S. D. Frey. 2015. Long-term forest soil warming alters microbial communities in temperate forest soils. *Frontiers in Microbiology* 6.

Hooper, D.U. 2005. Effects of biodiversity on ecosystem functioning: a consensus of current knowledge. *Ecological Monographs* 75:3-35.

IPCC 2013. The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK.

Jenny, H. 1941. Factors of soil formation. McGraw-Hill, New York, New York, USA.

Karhu, K. 2014. Temperature sensitivity of soil respiration rates enhanced by microbial community response. *Nature* 513:84.

Moore, J. A. M., J. Jiang, W. M. Post, and A. T. Classen 2015. Decomposition by ectomycorrhizal fungi alters soil carbon storage in a simulation model. *Ecosphere* 6(3):29.

Singh, H. B. 2010. Pollution influences on atmospheric composition and chemistry at high northern latitudes: boreal and California forest fire emissions. *Atmospheric Environment* 44:4553-4564.

Verheijen, L., R. Aerts, V. Brovkin, J. Cavender-Bares, J. Cornelissen, J. Kattge, and P. Bodegom. 2015. Inclusion of ecologically based trait variation in plant functional types reduces the projected land carbon sink in an earth system model. Global Change Biology.

Whitaker, J., N. Ostle, A. T. Nottingham, A. Ccahuana, N. Salinas, R. D. Bardgett, P. Meir, and N. P. McNamara. 2014. Microbial community composition explains soil respiration responses to changing carbon inputs along an Andes-to-Amazon elevation gradient. *Journal of Ecology* 102:1058-107.

Wieder, W., G. Bonan, and S. Allison. 2013. Global soil carbon projections are improved by modelling microbial processes. *Nature Climate Change* 3:909-912.
Zak, D. R., W. E. Holmes, N. W. MacDonald and K. S. Pregitzer 1999. Soil temperature, matric potential and the kinetics of microbial respiration and nitrogen mineralization. *Soil Science Society of America Journal* 63:575-584.

Zogg, G. P., D. R. Zak, D. B. Ringelberg, N. W. MacDonald, K. S. Pregitzer, and D. C. White. 1997. Compositional and functional shifts in microbial communities due to soil warming. *Soil Science Society of America Journal* 61:475-481.