Prolonged exposure does not increase soil microbial community response to warming along geothermal gradients

Radujković, Dajana; Verbruggen, Erik; Sigurðsson, Bjarni D.; Leblans, NI; Vica, S; Weedon, JT

doi:10.1101/102459

Cited by 3 publications

(10 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This occurred despite warming having no detectable influence over microbial community composition at the genus to operational taxonomic unit (OTU) level (i.e. OTU relative abundances; Supplementary Figs S3 & S4; ref 24). While it has been suggested that microbes acclimate to new thermal regimes9,22, we found no evidence to support this mechanism.…”

mentioning

confidence: 99%

Microbial temperature sensitivity and biomass change explain soil carbon loss with warming

et al. 2018

Self Cite

View full text Add to dashboard Cite

Soil microorganisms control carbon losses from soils to the atmosphere 1 – 3 , yet their responses to climate warming are often short-lived and unpredictable 4 – 7 . Two mechanisms, microbial acclimation and substrate depletion, have been proposed to explain temporary warming effects on soil microbial activity 8 – 10 . However, empirical support for either mechanism is unconvincing. Here we used geothermal temperature gradients (> 50 years of field warming) 11 and a short-term experiment to show that microbial activity (gross rates of growth, turnover, respiration and carbon uptake) is intrinsically temperature sensitive and does not acclimate to warming (+ 6 ºC) over weeks or decades. Permanently accelerated microbial activity caused carbon loss from soil. However, soil carbon loss was temporary because substrate depletion reduced microbial biomass and constrained the influence of microbes over the ecosystem. A microbial biogeochemical model 12 – 14 showed that these observations are reproducible through a modest, but permanent, acceleration in microbial physiology. These findings reveal a mechanism by which intrinsic microbial temperature sensitivity and substrate depletion together dictate warming effects on soil carbon loss via their control over microbial biomass. We thus provide a framework for interpreting the links between temperature, microbial activity and soil carbon loss on timescales relevant to Earth’s climate system.

show abstract

mentioning

confidence: 99%

Microbial temperature sensitivity and biomass change explain soil carbon loss with warming

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…A final smaller group (13% of variables, 6 plant-related, 3 microbe-related, 8 soil properties) resisted 5-8 years, but not >50 years, of warming (Fig. 2c,f), and represented apparently buffered changes to some aspects of plant metabolism 30 , stoichiometry and growth, alongside lagged declines in the richness of plant and soil fungal communities 27 (Fig. 3c,f).…”

Section: Grouped Variables and Their Responses To Warmingmentioning

confidence: 99%

“…Although these variables were only a subset of those measured, they were responsible for eliciting the same warming response from the EOF of the full ecosystem. These variables included ephemeral increases in microbial activity 1 , plant phenology 26 and plant carbon to nitrogen ratios, temporary shifts in some aspects of soil fungal community composition 27 and attenuating losses of root, soil fungal and soil bacterial biomass (Fig. 3b,e).…”

Section: Grouped Variables and Their Responses To Warmingmentioning

confidence: 99%

“…2a,d). This group included rapid and temporally consistent shifts in soil abiotic properties, the composition of plant and soil microbial, and particularly bacterial, communities 27 and declines in the soil carbon stock and other organic matter pools 29 (Fig. 3a,d).…”

Section: Grouped Variables and Their Responses To Warmingmentioning

confidence: 99%

“…3d,e) 1,32 , create a transitory phase where elevated biotic activity persists after soil organic matter is depleted (here, still occurring after 5-8 years of warming). Such "ecological inertia" is temporary because it reflects a deficit between ecosystem supply and biotic demand, which selects against species with exploitative resource use strategies (for example, arbuscular mycorrhizal fungi; see 27 ) and leads to community restructuring over 8 to 50 years (Fig. 3c,f).…”

Section: A Framework For the Ecosystem's Response To Warmingmentioning

confidence: 99%

See 2 more Smart Citations

A systemic overreaction to years versus decades of warming in a subarctic grassland ecosystem

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

Temperature adaptation of soil bacterial communities across the Arctic

Rijkers¹

View full text Add to dashboard Cite

Microorganisms that inhabit soils across the Arctic are typically well adapted to low temperatures and are highly responsive to temperature increases. A change in temperature adaptation of microbial communities might affect how fast they will decompose soil organic matter in a warmed Arctic. Currently, the potential change in temperature adaptation of soil bacterial communities is under scientific debate, due to contrasting observations made in field and laboratory settings. Therefore, the overall aim of this thesis was to evaluate the current temperature adaption of soil bacterial communities in the Arctic and to investigate whether the temperature adaptation of arctic soil bacterial communities shifts when exposed to warmed conditions. In Chapter 2, the optimal growth temperature of bacterial communities increased when comparing samples from the colder sites to warmer sites. I observed that one of the most important factors for their temperature adaptation was the mean maximum soil temperature. I concluded from this study that increasing temperatures – especially summer temperatures – will likely alter the temperature adaptation of bacterial communities in arctic soils. To confirm this hypothesis, I conducted an incubation study with 8 soils collected from the (sub-) Arctic and exposed them to different temperatures, ranging between 0 and 30°C. When the soils were incubated, the bacterial communities altered their temperature adaptation depending on the incubation temperature. In the third chapter, I also found that the induced change in temperature adaptation of soil bacterial communities was accompanied by a change in the overall composition of the bacterial community. Therefore, I hypothesized that the individual response of bacterial species to soil warming might reflect the temperature adaptation. Thus, the abundance of particular bacterial species in a soil sample could be potentially used for estimating the temperature adaptation of soil bacterial communities. In chapter 4, I evaluated the use of bacterial species abundance as indicator of bacterial communities responding to soil warming. Along a natural warming gradient in Iceland, I show that, while there are changes in the composition of bacterial communities of grassland soil in response to soil warming, there are only very few bacterial species that respond to the warming through multiple and multiple levels of warming. Therefore, is limited use of bacterial abundance data in predicting the temperature adaptation and response to warming for soil bacterial communities. Overall, I did not observe bacterial species that are both 1. common amongst many soil types and 2. respond consistently to soil warming. In chapter 5, I used a trait-based model approach to test whether the current theoretical framework around thermal traits of soil bacterial species can explain the relationship between temperature adaptation of soil bacterial communities and the temperatures that they are exposed to. The model made relatively accurate predictions about the temperature adaptation of soil bacterial communities. Furthermore, I discuss which traits related to the thermal niche of a bacterial species are relevant for improved modelling. Finally, I conclude in Chapter 6 that bacterial communities will likely alter their temperature adaptation in response to long term exposure to warming. It will be important to further assess the influence of these changes on the functioning on soil bacterial communities in the Arctic. From this thesis the view emerges that changes in the temperature adaptation of soil bacterial communities are likely due to the changes in the ideal temperature range of individual bacterial species. Accurate predictions for the current and future temperature adaptation of soil bacterial communities will require more in-depth knowledge of the traits that bacteria possess related to temperature.

show abstract

Prolonged exposure does not increase soil microbial community response to warming along geothermal gradients

Cited by 3 publications

References 52 publications

Microbial temperature sensitivity and biomass change explain soil carbon loss with warming

Microbial temperature sensitivity and biomass change explain soil carbon loss with warming

A systemic overreaction to years versus decades of warming in a subarctic grassland ecosystem

Temperature adaptation of soil bacterial communities across the Arctic

Contact Info

Product

Resources

About