Seasonal Changes In Soil Temperature Research Articles

Contrasting sensitivity of soil bacterial and fungal community composition to one year of water limitation in Scots pine mesocosms.

The soil microbiome is crucial for regulating biogeochemical processes and can thus strongly influence tree health, especially under stress conditions. However, little is known about the effect of prolonged water deficit on soil microbial communities during the development of saplings. We assessed the response of prokaryotic and fungal communities to different levels of experimental water limitation in mesocosms with Scots pine saplings. We combined analyses of physicochemical soil properties and tree growth with DNA metabarcoding of soil microbial communities throughout four seasons. Seasonal changes in soil temperature and soil water content and a decreasing soil pH strongly influenced the composition of microbial communities but not their total abundance. Contrasting levels of soil water contents gradually altered the soil microbial community structure over the four seasons. Results indicated that prokaryotic communities were less resistant to water limitation than fungal communities. Water limitation promoted the proliferation of desiccation-tolerant, oligotrophic taxa. Moreover, water limitation and an associated increase in soil C/N ratio induced a shift in the potential lifestyle of taxa from symbiotic to saprotrophic. Overall, water limitation appeared to alter soil microbial communities involved in nutrient cycling, pointing to potential consequences for forest health affected by prolonged episodes of drought.

Soil microbes support Janzen's mountain passes hypothesis: The role of local-scale climate variability along a tropical montane gradient.

Tropical montane ecosystems are the centers of biodiversity, and Janzen proposed that mountain climate variability plays a key role in sustaining this biodiversity. We test this hypothesis for soil bacteria and fungi along a 265-1,400 m elevational gradient on Hainan Island of tropical China, representing diverse vegetation types from deciduous monsoon forest to cloud forest. We found that bacterial and fungal diversity declined as elevation increased, and the dissimilarity of both groups increased with increasing separation in elevation, although changes in bacteria were larger than in fungi. Seasonal alterations and the range of soil moisture in the growing season were found to be the dominant drivers of fungal richness and Shannon diversity, whereas soil pH was the major driver of bacterial diversity. Dissimilarities of bacterial and fungal communities were best predicted by climate, particularly seasonal changes in soil temperature, with weaker influences of soil physicochemistry and vegetation. The dominant effect of seasonality in soil temperature was further detected in cloud forests, which harbored a higher proportion of unique bacterial species and dissimilarity of bacterial and fungal communities. Our findings suggest that local-climate variability plays a crucial role in structuring the distribution of soil microbial communities along a tropical montane gradient, which generally supports Janzen's hypothesis. Such a sensitivity to climatic variability suggests that soil microbial communities along tropical montane gradients may shift in response to future climate scenarios.

Monitoring of Seasonal Variations in Ground Temperature

The paper considers the problem of monitoring seasonal changes in soil temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal changes in soil temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal changes in soil temperature based on the results of numerical modeling of the penetration of seasonal fluctuations in soil temperature in 2014-2017 in MATLAB environment at the model site of the MSU Meteorological Observatory. The results of numerical simulation of the penetration of seasonal temperature fluctuations in the ground at the MSU meteorological site in 2014-2017 in the MATLAB environment are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen soils and assess the stability of foundations and buildings and linear structures located on them in the conditions of the North and mountainous territories. Therefore, the presented methodology can serve as a good help for monitoring and preventing the destruction of the studied structures in the conditions of climate warming.

Monitoring of Seasonal Variations in Ground Temperature

The paper considers the problem of monitoring seasonal changes in soil temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal changes in soil temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal changes in soil temperature based on the results of numerical modeling of the penetration of seasonal fluctuations in soil temperature in 2014-2017 in MATLAB environment at the model site of the MSU Meteorological Observatory. The results of numerical simulation of the penetration of seasonal temperature fluctuations in the ground at the MSU meteorological site in 2014-2017 in the MATLAB environment are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen soils and assess the stability of foundations and buildings and linear structures located on them in the conditions of the North and mountainous territories. Therefore, the presented methodology can serve as a good help for monitoring and preventing the destruction of the studied structures in the conditions of climate warming.

Effects of forest disturbance on seasonal soil temperature changes in the Tatra Mountains in southern Poland

Abstract The purpose of the study was to examine the effects of forest disturbance on seasonal changes in soil temperature in the Tatra Mountains (Poland). In the years 2015–2020 soil temperatures were measured at a depth of 20 cm on north- and south-facing mountain slopes in a catchment where forest was disturbed by hurricane-force winds in 2013 and in a control neighboring woodland catchment. The effect of forest disturbance was manifested first and foremost in an increase in the soil temperature during the summer months – average by 1.8 to 2.4 °C on a south-facing mountain slope – and by about 1 °C on a north-facing slope. The buffer effect of forest on soil temperature can be observed via lower coefficients of correlation between soil temperature and air temperature in a woodland catchment versus a disturbed catchment in the summer. In the winter, the effect of forest disturbance on soil temperature was less pronounced than in the summer. Small differences in soil temperature in the winter between the woodland catchment and the disturbed catchment were associated with the presence of snow cover and its capacity to yield thermal insulation. Good insulation of the soil from the atmosphere generated by snow cover yielded a very weak relationship between soil temperature and air temperature in the winter. In springtime the soil temperature increased the fastest on a south-facing slope in the disturbed catchment while in the autumn season, soil temperatures declined most rapidly on a slope facing north in the disturbed catchment.

Температурний режим грунтових масивів Як геологічний вплив на основи будівель

Проаналізовані результати спостережень за температурою ґрунту на 11 метеостанціях України. Розроблена методика визначення мінімальних та максимальних розрахункових значень температури ґрунту. Визначені розрахункові значення температури ґрунту для глибин до 3,2 м, проаналізовані та описані їх залежності від глибини й періоду повторюваності. Результати дослідження можуть бути використані в теплотехнічних розрахунках підземних частин будівельних об’єктів.

芦芽山针叶林分布上下限土壤温度及含水量的季节差异

芦芽山针叶林分布上下限土壤温度及含水量的季节差异

Understanding drivers of peatland extracellular enzyme activity in the PEATcosm experiment: mixed evidence for enzymic latch hypothesis

Our objective was to assess the impacts of water table position and plant functional groups on peatland extracellular enzyme activity (EEA) framed within the context of the enzymic latch hypothesis. We utilized a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: Ericaceae, sedge, Ericaceae and sedge unmanipulated) in twenty-four 1 m3 intact peatland mesocosms. We measured bulk peat and porewater phase oxidative and hydrolytic enzyme activities monthly from June - October 2012. We also measured physical and porewater chemical constituents in tandem to analyze environmental influences on seasonal enzyme activities. No PFG effects on EEA with WT affecting only acid-phosphatase activity in porewater. Strong seasonal dynamics in EEAs overshadowed our manipulations. Analyses indicated phenolic concentrations were influenced by peat redox potential and negatively correlated with phenol oxidase activity as expected from enzymic latch hypothesis. However, no hydrolytic EEA was influenced by total phenolics, but driven largely by seasonal changes in soil temperature and increasing DOC concentrations in porewater. Our results suggest no support for final step in enzymic latch, in which phenolics are posited to regulate hydrolytic EEAs. Mechanisms regulating seasonal influences remain to be elucidated.

A new approach to modelling of a horizontal geo-heat exchanger with an internal source term

This paper presents a new approach to considering the effect of seasonal changes in soil temperature on the performance of a horizontal geo heat exchanger. It is different from extant models which consider the seasonal changes in soil temperature by applying a real energy balance on the ground surface. In the new model, the seasonal changes in soil temperature, which are affected by the thermal interaction between the ground and the atmosphere, are expressed as an internal source term. The value of the internal source term depends on the soil density, soil specific heat, soil temperature difference during summer and winter, and time period. The simulation results show that the new approach, which takes into account the effect of periodic soil temperature fluctuations on the performance of the horizontal geo heat exchanger, is valid. The validated model is then used to conduct a sensitivity analysis to investigate the effects of the pipe length, fluid flow rate, inlet fluid temperature, and burial depth on the thermal performance of the horizontal geo heat exchanger.

A comparison of spatial interpolation methods for soil temperature over a complex topographical region

Soil temperature variability data provide valuable information on understanding land-surface ecosystem processes and climate change. This study developed and analyzed a spatial dataset of monthly mean soil temperature at a depth of 10 cm over a complex topographical region in southwestern China. The records were measured at 83 stations during the period of 1961–2000. Nine approaches were compared for interpolating soil temperature. The accuracy indicators were root mean square error (RMSE), modelling efficiency (ME), and coefficient of residual mass (CRM). The results indicated that thin plate spline with latitude, longitude, and elevation gave the best performance with RMSE varying between 0.425 and 0.592 °C, ME between 0.895 and 0.947, and CRM between −0.007 and 0.001. A spatial database was developed based on the best model. The dataset showed that larger seasonal changes of soil temperature were from autumn to winter over the region. The northern and eastern areas with hilly and low-middle mountains experienced larger seasonal changes.

Reduced throughfall decreases autotrophic respiration, but not heterotrophic respiration in a dry temperate broadleaved evergreen forest

Climate change may have major implications on soil respiration dynamics and the carbon sink strength of forest soils. To assess the effect of climate change on soil respiration (RS), it is crucial to understand individual responses of autotrophic (RA) and heterotrophic (RH) components. We investigated the effect of continuously (20 months) reduced throughfall (TFR, −40%) and the influence of seasonal changes in soil temperature and moisture on RS, RA and RH, partitioned by root exclusion, in a dry temperate broadleaved evergreen eucalypt forest in south-eastern Australia. TFR decreased mean RS from 4.7±0.1 (Control) to 3.8±0.1 (TFR) μmolCO2m−2s−1 (−19%). TFR indicated a strong decrease in RA from 2.5±0.1 (Control) to 1.5±0.1 (TFR) μmolCO2m−2s−1 (−40%), but had no effect on RH. The mean relative contribution of RH to RS was 47% in the Control and increased to 61% under TFR. RS was the result of distinct seasonal patterns and dependencies of RH and RA on environmental variables. Soil temperature was a good predictor of RH (Control: R2=0.72, TFR: R2=0.75), but not of RA. In contrast, RH was not limited by soil moisture, while RA was partly influenced by soil moisture (Control: R2=0.29, TFR: R2=0.56). The lack of response of RH to changes in soil moisture (seasonal and under TFR) was likely influenced by the high rainfall conditions such that soil moisture did not decrease to a point where it limited soil microbial decomposition processes. Our results show that TFR implied the strongest effect on RA and that changes in soil temperature and moisture alone do not sufficiently explain seasonal changes in RA and RS. This indicates that biotic factors, such as plant internal carbon allocation, may exert a stronger influence on RA and hence, RS. In short-term a reduction in rainfall will lead to a decrease of soil respiration in dry temperate broadleaved evergreen eucalypt forests. The magnitude of this decrease and its persistence under extended drought will be greatly influenced by seasonal and inter-annual climate variability and potential changes in plant carbon allocation.

Modelling of a Horizontal Geo Heat Exchanger with an Internal Source Term Approach

This paper presents a new approach to considering the effect of seasonal changes in soil temperature on the performance of a horizontal geo heat exchanger. It is different from the existing models which consider seasonal changes in soil temperature by applying a real energy balance on the ground surface. In the new model, the seasonal changes in soil temperature, which are affected by the thermal interaction between the ground and the atmosphere, are expressed as an internal source term. The value of the internal source term depends on the soil density, soil specific heat, soil temperature difference during summer and winter, and time period. The simulation results show that the new approach, which takes into account the effect of periodic soil temperature fluctuations on the performance of the horizontal geo heat exchanger, is valid.

Carbon input manipulation affects soil respiration and microbial community composition in a subtropical coniferous forest

We determined the effects of aboveground and belowground C inputs on soil CO2 efflux and microbial community composition by phospholipid fatty acids using aboveground litter addition or removal and root trenching in a subtropical forest in Southern China. From January 2011 to December 2011, soil respiration varied with the seasonal changes in soil temperature and water content, but its pattern was not altered by C input manipulation. The effects of C input manipulation on the temperature sensitivity of soil respiration was season-dependent, which were greater in the dormant season than in the growing season. Litter addition increased the soil respiration by 33% compared with the control, whereas litter removal decreased it by 22.6%. Root trenching decreased soil respiration by 20.4%. Aboveground litter decomposition, root and rhizosphere respiration, and mineral soil respiration contributed to 22.3%, 20.1%, and 57.6% of total soil CO2 efflux, respectively. We also found that increase in soil CO2 efflux induced by litter addition was 10.4% greater than decrease by litter removal. Litter removal increased 21.6% of the concentration of Gram-positive bacteria and decreased 32.8% of the bacteria to fungi ratio, compared with the control. Root trenching increased the concentrations of bacteria, fungi, and actinomycetes by 28.8%, 161.2% and 32.5%, respectively, but decreased the Gram-negative to Gram-positive bacteria and the bacteria to fungi ratios by 57.4% and 107.9%. C input treatment did not increase the Gram-positive bacteria but nor decreased the Gram-negative to Gram-positive bacteria ratio. The concentration of the 16:0 PLFA and the Gram-negative to Gram-positive bacteria ratio were significantly correlated with soil respiration. These results suggest that root C input has greater influence on soil microbial community composition than the aboveground litter C input.

Soil moisture overshadows temperature control over soil CO2 efflux in a Pinus canariensis forest at treeline in Tenerife, Canary Islands

Soil CO2 efflux (ES) of a 50 year-old Mediterranean Pinus canariensis Chr. Sm. Ex DC. at treeline in Tenerife (Canary Islands), an ecotone with strong seasonal changes in soil temperature and soil water availability. ES was measured in weekly to monthly intervals between October 2008 and September 2009. Although ES varied markedly throughout the year, the temperature sensitivity of soil CO2 efflux (QS) and ES normalized to 10 °C temperature (ES10) did not vary considerably with respect to season. The Q10 values were 1.92 for the cold and wet season and 1.98 for the warm and dry season, respectively. The corresponding ES10 values were 0.61 and 0.50 μmol m−2 s−1, respectively. ES was largely controlled by soil temperature (Ts) and 76% of the annual variation in ES was explained by this factor. However, during the warm and dry period when soil water potential in 25–30 cm depth (Ψ) was lower than −0.04 MPa and during the cold and wet period when Ψ was higher than −0.02 MPa, Ts control over ES was limited. A model combining soil temperature and soil water availability explained 75% of the annual variation in ES. When integrated over an entire year, ES was 314 g carbon m−2 and the contribution of the cold and wet season (October–May; 214 days) and of the warm and dry season (June–September; 154 days) to annual ES was 48 and 52%, respectively.Our results reveal that soil water availability limits temperature control over ES during the wet and cold season and during the warm and dry period in Mediterranean forest ecosystems at their upper distribution limit.

Dormancy cycling in Arabidopsis seeds is controlled by seasonally distinct hormone-signaling pathways

Seeds respond to environmental signals, tuning their dormancy cycles to the seasons and thereby determining the optimum time for plant establishment. The molecular regulation of dormancy cycling is unknown, but an extensive range of mechanisms have been identified in laboratory experiments. Using a targeted investigation of gene expression over the dormancy cycle of Arabidopsis seeds in the field, we investigated how these mechanisms are seasonally coordinated. Depth of dormancy and gene expression patterns were correlated with seasonal changes in soil temperature. The results were consistent with abscisic acid (ABA) signaling linked to deep dormancy in winter being repressed in spring concurrent with enhanced DELLA repression of germination as depth of dormancy decreased. Dormancy increased during winter as soil temperature declined and expression of ABA synthesis (NCED6) and gibberellic acid (GA) catabolism (GA2ox2) genes increased. This was linked to an increase in endogenous ABA that plateaus, but dormancy and DOG1 and MFT expression continued to increase. The expression of SNF1-related protein kinases, SnrK 2.1 and 2.4, also increased consistent with enhanced ABA signaling and sensitivity being modulated by seasonal soil temperature. Dormancy then declined in spring and summer. Endogenous ABA decreased along with positive ABA signaling as expression of ABI2, ABI4, and ABA catabolism (CYP707A2) and GA synthesis (GA3ox1) genes increased. However, during the low-dormancy phase in the summer, expression of transcripts for the germination repressors RGA and RGL2 increased. Unlike deep winter dormancy, this represson can be removed on exposure to light, enabling the completion of germination at the correct time of year.

Effect of Seasonal Changes in Soil Temperature and Moisture on Wood Consumption and Foraging Activity of Formosan Subterranean Termite (Isoptera: Rhinotermitidae)

The objective of this study was to determine how seasonal changes affect the foraging activity and wood consumption of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in New Orleans, LA. There was a significant correlation between wood consumption and air temperature, soil temperature, and soil moisture, but not precipitation or number of rainy days. In the first year of the study, wood consumption was the lowest in December, February, and March. Wood consumption in January was not significantly different from consumption during the rest of the year. There were no seasonal changes in the number of underground monitoring stations occupied by termites. In the second year of the study, wood consumption was lowest from January to March. There was a significant decrease in the number of monitoring stations occupied by termites during the winter. This study determined that C. formosanus will remain in monitoring stations and resume feeding during warmer periods of a mild winter if average soil temperatures remain above 15 degrees C. Only prolonged periods of cold weather, with average soil temperatures below 15 degrees C, caused a significant number of termites to abandon underground monitoring stations. Seasonal changes in foraging activity would probably only disrupt baiting programs during severe winters in New Orleans, LA.

Seasonal changes in soil temperature within mustard crop stand

Seasonal changes in soil temperature within mustard crop stand

Kangaroo Rats Remodel Burrows in Response to Seasonal Changes in Environmental Conditions

Burrow architecture enhances important animal functions such as food storage, predator avoidance, and thermoregulation. Occupants may be able to maximize fitness by remodeling burrows in response to seasonal changes in climate and predation risk. My objective was to examine how banner-tailed kangaroo rats (Dipodomys spectabilis) modify the number of burrow entrances in response to seasonal conditions. For 3 yr, I monitored fluctuations in number of burrow entrances in kangaroo rat mounds. Individual kangaroo rats continually remodeled mounds in response to seasonal conditions. Compared to summer, mounds in winter had approximately 50% fewer entrances and plugged entrances were common. Monthly differences in number of entrances were closely linked with seasonal changes in soil temperature and precipitation. Number of entrances decreased as soil temperature and precipitation declined. Changes in burrow entrances likely reflect seasonal differences in the relative importance of burrow functions. Fewer burrow entrances during winter would create a warmer microclimate by reducing convective heat loss in mounds, resulting in thermoregulatory savings for occupants. During the summer, thermoregulatory costs of kangaroo rats are low, but risk of seed cache spoilage and predation from snakes increases. Adding burrow entrances after large summer rainfall events would increase the evaporation rate within mounds, reducing spoilage of seed caches. More burrow entrances would also reduce predation risk in the summer by providing additional escape routes.

Autotrophic and heterotrophic respiration in needle fir and Quercus-dominated stands in a cool-temperate forest, central Korea

To investigate annual variation in soil respiration (R (S)) and its components [autotrophic (R (A)) and heterotrophic (R (H))] in relation to seasonal changes in soil temperature (ST) and soil water content (SWC) in an Abies holophylla stand (stand A) and a Quercus-dominated stand (stand Q), we set up trenched plots and measured R (S), ST and SWC for 2 years. The mean annual rate of R (S) was 436 mg CO(2) m(-2) h(-1), ranging from 76 to 1,170 mg CO(2) m(-2) h(-1), in stand A and 376 mg CO(2) m(-2) h(-1), ranging from 82 to 1,133 mg CO(2) m(-2) h(-1), in stand Q. A significant relationship between R (S) and its components and ST was observed over the 2 years in both stands, whereas a significant correlation between R (A) and SWC was detected only in stand Q. On average over the 2 years, R (A) accounted for approximately 34% (range 17-67%) and 31% (15-82%) of the variation in R (S) in stands A and Q, respectively. Our results suggested that vegetation type did not significantly affect the annual mean contributions of R (A) or R (H), but did affect the pattern of seasonal change in the contribution of R (A) to R (S).

Contribution of Root and Microbial Respiration to Soil CO 2 Efflux and Their Environmental Controls in a Humid Temperate Grassland of Japan

Soil CO 2 efflux, root mass, and root production were investigated in a humid temperate grassland of Japan over a growing season (Apr. to Sep.) of 2005 to reveal seasonal changes of soil CO 2 efflux, to separate the respective contributions of root and microbial respiration to the total soil CO 2 efflux, and to determine the environmental factors that control soil respiration. Minimal microbial respiration rate was estimated based on the linear regression equations between soil CO 2 efflux and root mass at different experimental sites. Soil CO 2 efflux, ranging from 4.99 to 16.29 μmol CO 2 m −2 s −1, depended on the seasonal changes in soil temperature. The root mass at 0–10 cm soil depth was 0.82 and 1.27 kg m −2 in Apr. and Sep., respectively. The root mass at 0–10 cm soil depth comprised 60% of the total root mass at 0–50 cm soil depth. The root productivity at 0–30 cm depth varied from 8 to 180 g m −2 month −1. Microbial and root respiration rates ranged from 1.35 to 5.51 and 2.72 to 12.06 μmol CO 2 m −2 s −1, respectively. The contribution of root respiration to the total soil CO 2 efflux averaged 53%, ranging from 33% to 72%. The microbial respiration rate was exponentially related to soil temperature at 10 cm depth ( R 2 = 0.9400, P = 0.002, n = 6), and the root respiration rate was linearly related to the root production at 0–30 cm depth ( R 2 = 0.6561, P = 0.042, n = 6).