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Microbe Mediated Attenuation Of Soil Respiration In Response To Soil Warming In A Temperate Oak Forest
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Book Synopsis Microbe-Mediated Attenuation Of Soil Respiration In Response To Soil Warming In A Temperate Oak Forest by : Junwei Luan
Download or read book Microbe-Mediated Attenuation Of Soil Respiration In Response To Soil Warming In A Temperate Oak Forest written by Junwei Luan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil respiration (Rs) in response to climate warming received wide concerns due to its role in terrestrial ecosystem carbon (C) cycling, but the warming-induced effects of soil microbes on soil respiration are still less understood, especially over time. Our study aims to understand the long-term warming induced effects of soil microbes on Rs. A field soil warming experiment used completely randomized design was conducted in a naturally regenerated oak forest (Quercus aliena) in central China. Soil warming were executed by infrared heater throughout the years from 2011 to 2015. Our results showed that soil temperature was a main factor in regulating Rs in a temperate oak forest, but soil water content only determined Rs when a naturally dry year occured. The positive effect of soil warming on Rs that was observed (i.e., 37.5 to 42.0% in the first two years) gradually diminished in the following three years (i.e., 0.9-15.4%). Significant positive warming effects on the temperature sensitivity of Rs (Q10) only occurred in the second year. Continuous soil warming caused the decline in nitrogen (N) availability, but a significant increase in microbial biomass-specific enzyme activities for N-acquisition. The attenuation of microbial biomass increment and the decreased ratio of enzymatic C:N acquisition contributed to the diminished warming effect on Rs over time. Our study suggests that microbe-mediated attenuation of Rs, accompanied by the concomitant decline in soil N availability in response to warming, should be taken into consideration in global C cycle modeling.
Book Synopsis Heterotrophic Soil Respiration in Warming Experiments by :
Download or read book Heterotrophic Soil Respiration in Warming Experiments written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The central objective of the proposed work was to develop a genomic approach (nucleic acid-based) that elucidates the mechanistic basis for the observed impacts of experimental soil warming on forest soil respiration. The need to understand the mechanistic basis arises from the importance of such information for developing effective adaptation strategies for dealing with projected climate change. Specifically, robust predictions of future climate will permit the tailoring of the most effective adaptation efforts. And one of the greatest uncertainties in current global climate models is whether there will be a net loss of carbon from soils to the atmosphere as climate warms. Given that soils contain approximately 2.5 times as much carbon as the atmosphere, a net loss could lead to runaway climate warming. Indeed, most ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon, producing such a positive feedback to rising global temperatures. Yet the IPCC highlights the uncertainty regarding this projected feedback. The uncertainty arises because although warming-experiments document an initial increase in the loss of carbon from soils, the increase in respiration is short-lived, declining to control levels in a few years. This attenuation could result from changes in microbial physiology with temperature. We explored possible microbial responses to warming using experiments and modeling. Our work advances our understanding of how soil microbial communities and their activities are structured, generating insight into how soil carbon might respond to warming. We show the importance of resource partitioning in structuring microbial communities. Specifically, we quantified the relative abundance of fungal taxa that proliferated following the addition of organic substrates to soil. We added glycine, sucrose, cellulose, lignin, or tannin-protein to soils in conjunction with 3-bromo-deoxyuridine (BrdU), a nucleotide analog. Active microbes absorb BrdU from the soil solution; if they multiply in response to substrate additions, they incorporate the BrdU into their DNA. After allowing soils to incubate, we extracted BrdU-labeled DNA and sequenced the ITS regions of fungal rDNA. Fungal taxa that proliferated following substrate addition were likely using the substrate as a resource for growth. We found that the structure of active fungal communities varied significantly among substrates. The active fungal community under glycine was significantly different from those under other conditions, while the active communities under sucrose and cellulose were marginally different from each other and the control. These results indicate that the overall community structure of active fungi was altered by the addition of glycine, sucrose, and cellulose and implies that some fungal taxa respond to changes in resource availability. The community composition of active fungi is also altered by experimental warming. We found that glycine-users tended to increase under warming, while lignin-, tannin/protein-, and sucrose-users declined. The latter group of substrates requires extracellular enzymes for use, but glycine does not. It is possible that warming selects for fungal species that target, in particular, labile substrates. Linking these changes in microbial communities and resource partitioning to soil carbon dynamics, we find that substrate mineralization rates are, in general, significantly lower in soils exposed to long-term warming. This suggests that microbial use of organic substrates is impaired by warming. Yet effects are dependent on substrate identity. There are fundamental differences in the metabolic capabilities of the communities in the control and warmed soils. These differences might relate to the changes in microbial community composition, which appeared to be associated with groups specialized on different resources. We also find that functional responses indicate temperature acclimation of the microbial community. There are distinct seasonal patterns and to long-term soil warming, with higher-temperature optima for soils exposed to warmer temperatures. To relate these changes within the microbial community to potential positive feedbacks between climate warming and soil respiration, we develop a microbial-enzyme model to simulate the responses of soil carbon to warming. We find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming. Specifically, reduced carbon-use efficiency limits the biomass of microbial decomposers and mitigates loss of soil carbon. However, microbial adaptation or a change in microbial communities could lead to an upward adjustment of the efficiency of carbon use, counteracting the decline in microbial biomass and accelerating soil-carbon loss. We conclude that the soil-carbon response to climate warming depends on the efficiency of soil microbes in using carbon.
Book Synopsis Forest Soil Respiration under Climate Changing by : Robert Jandl
Download or read book Forest Soil Respiration under Climate Changing written by Robert Jandl and published by MDPI. This book was released on 2018-10-09 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Forest Soil Respiration under Climate Changing" that was published in Forests
Book Synopsis Belowground Carbon Dynamics in Northern Hardwood Forests by : Gregory P. Zogg
Download or read book Belowground Carbon Dynamics in Northern Hardwood Forests written by Gregory P. Zogg and published by . This book was released on 1997 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Impacts of Climate Change on Soil Microorganisms in Northern Hardwood Forests by : Carley Jane Kratz
Download or read book Impacts of Climate Change on Soil Microorganisms in Northern Hardwood Forests written by Carley Jane Kratz and published by . This book was released on 2014 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: As global climate continues to change, it becomes more important to understand possible feedbacks from soils to the climate system. This dissertation focuses on soil microbial community responses to climate change factors in northern hardwood forests. Two soil warming experiments at Harvard Forest in Massachusetts, and a climate change manipulation experiment with both elevated temperature and increased moisture inputs in Michigan were sampled. The hyphal in-growth bag method was to understand how soil fungal biomass and respiration respond to climate change factors. Our results from phospholipid fatty acid (PLFA) analyses suggest that the hyphal in-growth bag method allows relatively pure samples of fungal hyphae to be partitioned from bacteria in the soil. The contribution of fungal hyphal respiration to soil respiration was examined in climate change manipulation experiments in Massachusetts and Michigan. The Harvard Forest soil warming experiments in Massachusetts are long-term studies with 8 and 18 years of +5 °C warming treatment. Hyphal respiration and biomass production tended to decrease with soil warming at Harvard Forest. This suggests that fungal hyphae adjust to higher temperatures by decreasing the amount of carbon respired and the amount of carbon stored in biomass. The Ford Forestry Center experiment in Michigan has a 2 x 2 fully factorial design with warming (+4-5 °C) and moisture addition (+30% average ambient growing season precipitation). This experiment was used to examine hyphal growth and respiration of arbuscular mycorrhizal fungi (AMF), soil enzymatic capacity, microbial biomass and microbial community structure in the soil over two years of experimental treatment. Results from the hyphal in-growth bag study indicate that AMF hyphal growth and respiration respond negatively to drought. Soil enzyme activities tend to be higher in heated versus unheated soils. There were significant temporal variations in enzyme activity and microbial biomass estimates. When microbial biomass was estimated using chloroform fumigation extractions there were no differences between experimental treatments and the control. When PLFA analyses were used to estimate microbial biomass we found that biomass responds negatively to higher temperatures and positively to moisture addition. This pattern was present for both bacteria and fungi. More information on the quality and composition of the organic matter and nutrients in soils from climate change manipulation experiments will allow us to gain a more thorough understanding of the mechanisms driving the patterns reported here. The information presented here will improve current soil carbon and nitrogen cycling models.
Book Synopsis Soil respiration in a mixed oak forest by :
Download or read book Soil respiration in a mixed oak forest written by and published by . This book was released on 1972 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Winter Soil Respiration in the Intermountain West by : Colin L. Tucker
Download or read book Winter Soil Respiration in the Intermountain West written by Colin L. Tucker and published by . This book was released on 2013 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last several decades research into soil respiration has accelerated dramatically, largely because of growing concern about the role of ecosystem CO2 emissions in driving climate change. Soil carbon (C) is the largest terrestrial pool of actively cycling C, such that any response of soil respiration to warming may form a positive feedback on climate change. By and large, most studies of soil respiration focus on growing season processes. In this dissertation, I address this knowledge gap by studying soil respiration in a set of winter-dominated ecosystems in southeast Wyoming, with a central focus of understanding controls on winter soil respiration. The unifying question is "How does winter soil respiration in seasonally snow-covered systems respond to a changing environment?" In this dissertation, I separately quantify autotrophic (roots and rhizosphere) and heterotrophic (decomposer microbes) soil respiration, and then analyze the controls on soil respiration. In particular, I focus on the of soil respiration to physical drivers such temperature, snow and soil water, and biotic drivers such as microbial biomass, substrate use dynamics, and root biomass. The overarching result is that while physical drivers may explain a substantial amount of the variation in soil respiration, biotic drivers must be included in any careful analysis of soil respiration. Variable snow depth is a critical driver of winter soil respiration due to its influence on soil temperature and water availability. However, soil organisms can acclimate to soil conditions, such that the response of soil respiration to changing snow depth and soil temperatures are probably not predictable from simple physical and empirical models.
Book Synopsis Response of Soil Temperature, Moisture, and Respiration Two Years Following Intensive Organic Matter and Compaction Manipulations in Oregon Cascade Forests by : Adrian Carlos Gallo
Download or read book Response of Soil Temperature, Moisture, and Respiration Two Years Following Intensive Organic Matter and Compaction Manipulations in Oregon Cascade Forests written by Adrian Carlos Gallo and published by . This book was released on 2017 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Forest soils contain a substantial portion of global terrestrial carbon stores. Forest management can influence the soil carbon pool and how soil organic matter functions. The long-term productivity of forests is an ongoing goal where land managers utilize biomass and timber. A site-specific understanding of intensively managed forests can ensure achievements of this goal. Within a managed forest in the western Oregon Cascades, treatments were installed to harvest three levels of biomass, with and without compaction, to monitor impacts to growing season characteristics of Douglas-fir roots. Soil temperature and moisture conditions were continuously monitored from 10 to 100cm depth, and three sources of soil respiration were measured monthly for two years immediately following treatments. Negligible differences in the length of growing season were detected, however the daily-10cm average, maximum, and diel flux of soil temperatures significantly increased by 1.5, 2.7, and 2.5°C, respectively, with increasing biomass harvesting. Organic matter removal strongly influenced growing season soil characteristics down to a 100cm depth. Diel temperature flux at 100cm for the least and most impacted treatments were 5.7 and 7.8°C, respectively, a magnitude equivalent to seasonal shifts in soil temperature at the same depth. In spite of favorable temperature and moisture conditions with less organic matter left on the surface, soil respiration was moderately higher on bole only harvests. A priming effect may explain why these sites with more surface biomass, although significantly cooler, had the highest rates of soil respiration. The combination of increased temperatures throughout the soil profile after forest harvesting, and higher additions of dissolved organic matter from forest residuals, could have an impact on deep soil carbon. These responses have implications for long-term nutrient cycling that have yet to be elucidated for deeper soils; but this should be considered when land managers are planning forest fertilization and rotation lengths.
Book Synopsis Temperature and Moisture Effects on Respiration in the Organic Horizon of a Pacific Northwest Forest Soil by : Hanna Maria Winter
Download or read book Temperature and Moisture Effects on Respiration in the Organic Horizon of a Pacific Northwest Forest Soil written by Hanna Maria Winter and published by . This book was released on 2014 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Warming and Simulated Rainfall on Soil Microbial Community Structure and Function by : Torri A. Ivancic
Download or read book The Effect of Warming and Simulated Rainfall on Soil Microbial Community Structure and Function written by Torri A. Ivancic and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil respiration, from plant roots and soil microbes, accounts for 60 - 80 percent of total ecosystem respiration, with the microbial component contributing approximately 54 percent. Global climate trends resulting from CO2 emissions include increased soil temperatures and changes in precipitation regimes resulting in less frequent, more intense rainfall events. Soil temperature and moisture availability drive soil respiration rates, but how they impact the microbial respiration is poorly qualified. I investigated how the soil microbial community responds to changes in temperature and moisture availability in a laboratory based experiment. Soils from a mixed hardwood forest under two thermal regimes received either a large or small simulated rainfall event. A large event corresponded with the highest recorded daily average rainfall event for a 30 year period and a small event was half that amount. Soil temperature, moisture, and respiration were measured at 30 minute intervals for the duration of the experiment. I used the following metrics to quantify microbial respiratory respoinse: (1) maximum rate of soil microbial respiration (SMRmax); (2) the amount of time it took to reach SMRmax (Tmax); (3) the amount of time it took to return to pre-rainfall rates of soil microbial respiration (Tduration); and the total CO2 production in each mesocosm associated with rainfall (SMRtotal). Temperature treatments positively influenced SMRmax, but had no impact on my other metrics. Rainfall event size positively impacted SMRmax, Tduration, and SMRtotal. My research suggests that in temperate mixed hardwood forest soils moisture is a stronger driver of soil microbial respiration than temperature.
Book Synopsis The Temperature Response of Soil Respiration from Labile and Stable Carbon by : Kristyn Bailee Numa
Download or read book The Temperature Response of Soil Respiration from Labile and Stable Carbon written by Kristyn Bailee Numa and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Nitrogen and Shosphorus Addition on Soil Respiration in Northern Hardwood Forests by : Shiyi Li
Download or read book Effects of Nitrogen and Shosphorus Addition on Soil Respiration in Northern Hardwood Forests written by Shiyi Li and published by . This book was released on 2018 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil respiration - the CO2 efflux from the forest soil surface - is an important indicator of root and microbial activity and is sensitive to global changes such as climate warming, anthropogenic nitrogen deposition and elevated atmospheric CO2. I evaluated the response of total soil respiration (TSR) to changes in soil nutrient availability in temperate deciduous forests in New Hampshire. Low-level N (3 g/m2/year), P (1 g/m2/year) or N + P have been applied annually to thirteen northern hardwood stands of different age and site quality since 2011. My analysis of TSR for 2013, 2014, 2016, and 2017 confirmed the overall suppression effect of N addition across these stands (p
Book Synopsis Forest Soil Respiration Under Climate Changing by : Mirco Rodeghiero
Download or read book Forest Soil Respiration Under Climate Changing written by Mirco Rodeghiero and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The respiration of forest soils and the major factors controlling its rate are fairly well understood. The process is of utmost significance because its balance with the fixation of CO2 in the biomass defines whether a particular site is a source or sink of atmospheric CO2. Currently, the measurement of soil respiration in the field requires rather expensive experimental installations. Nevertheless, there are still some caveats in our understanding, such as the separation of autotrophic and heterotrophic soil respiration, the relevance of different groups of soil organisms, the effect of ecosystem disturbances in different types of forests on soil respiration with respect to magnitude and duration, the adaptation of soil respiration to changing site conditions, and the regional prediction of soil respiration, based on proxy data. Technical progress and additional contributions on process understanding will put us in the position of better predictions of the forest soil respiration. We encourage studies from all fields, including experimental studies, monitoring approaches and models, to contribute to this Special Issue in order to promote knowledge and adaptation strategies for the preservation, management, and future development of forest ecosystems.
Book Synopsis Effects of Air Vs. Air+soil Heating During a Simulated Heat Wave on White Oak (Quercus Alba) and Black Oak (Quercus Veluntina) by : Nicole E. Lightle
Download or read book Effects of Air Vs. Air+soil Heating During a Simulated Heat Wave on White Oak (Quercus Alba) and Black Oak (Quercus Veluntina) written by Nicole E. Lightle and published by . This book was released on 2013 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extreme weather events are a growing focus of global climate change research. Extreme events, which occur abruptly and unpredictably, are often more detrimental to terrestrial vegetation than gradual shifts in climate. One type of event, the summer heat wave, may already be increasing in some areas of the world. Large-scale reductions in Net Primary Productivity and mortality have been reported during heat waves in forested ecosystems. Unfortunately, our understanding of how abrupt heat-stress affects woody species during heat waves lags behind our knowledge of herbaceous species that have been more widely studied in experimental manipulations. A few studies of herbaceous species also suggest that the coupling of soil heating to air heating can change the overall plant response to heat waves. To investigate air vs. air+soil heating in woody species, we manipulated the temperature of both shoots and roots separately for both white and black oak seedlings by insulating the soil during heat-stress to the shoot (35 vs. 40°C for 4 days, white oak; 35°C for 8 days, black oak). Interestingly, at moderate heat-stress temperature (35°C), net photosynthesis declined and internal CO2 concentration of leaves increased more when the roots were insulated in both species. Hence, concurrent soil warming prevented metabolic damage to leaves during moderate heat-stress, suggesting that direct heat to the roots increased shoot thermotolerance. In both experiments, differences in air vs. air+soil heating effects on root respiration were directly related to differences in soil temperatures, such that root respiration was higher with air+soil heating. In neither experiment were soil temperature effects related to plant water status. These results suggest that both direct and indirect effects of soil warming may occur in woody species during a heat wave, but that the response may depend on the severity and duration of the heat-stress. Future research is needed to determine the underlying mechanism for differences between air vs. air+soil heating during a heat wave.
Book Synopsis Adaptation of Soil Fungi to Warming and Consequences for Decomposition and the Carbon Cycle by : Adriana L. Romero-Olivares
Download or read book Adaptation of Soil Fungi to Warming and Consequences for Decomposition and the Carbon Cycle written by Adriana L. Romero-Olivares and published by . This book was released on 2017 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studying soil carbon (C) losses and carbon dioxide (CO 2) feedbacks to the atmosphere under global climate change allows us to quantify and understand how our ecosystems are responding to warming. To accurately project the fate of the terrestrial C, we need to incorporate processes that are pivotal in shaping microbial communities that are responsible of processing the C in the soil. One of these processes is the evolutionary adaptation to warming which has been difficult to study because it may only be noticeable on the long term. The goal of my dissertation was to examine soil microbes, their response and adaptation to warming, and consequences to the C cycle. In Chapter 1, I synthesized data from 25 field warming experiments to assess the effect of microbial responses---relevant to the C cycle---to warming over time. I found that the effect of soil respiration decreases as warming progresses and explored the potential microbial-related causes of this decrease. In my second chapter, I experimentally adapted the model fungus Neurospora discreta to warming and analyzed physiological traits important for the C cycle before and after adaptation. I discovered that when N. discreta adapts to warming it allocates more resources to increase its fitness by producing more spores at the expense of biomass. I found that adaptation to warming is accompanied by increases in CO2 respiration potentially due to higher production of energetically expensive spores. In this chapter, I discussed the potential consequences for the terrestrial C if the soil microbial community adapts in a similar manner as N. discreta . Finally, in my third chapter, I quantified decomposition of specific C fractions in litter in a long-term field warming experiment. I found that the proportional losses of recalcitrant vs non-recalcitrant C was higher in warmed plots compared to control plots. Similarly, the ratio of microbial extracellular enzyme activities responsible for breaking down recalcitrant C was higher under warming compared to enzymes that break down non-recalcitrant C. Collectively, in my dissertation research I integrated the process of evolutionary adaptation of microbes to warming, thus providing an overview of the potential long-term effects of warming to decomposition and the C cycle.
Book Synopsis Soil Respiration in Intact and Clearcut Northern Hardwood Forests by : David E. Toland
Download or read book Soil Respiration in Intact and Clearcut Northern Hardwood Forests written by David E. Toland and published by . This book was released on 1993 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Interannual Dynamics of Soil Respiration in Managed Oak Forrests in Missouri Ozarks by : Jianye Xu
Download or read book Interannual Dynamics of Soil Respiration in Managed Oak Forrests in Missouri Ozarks written by Jianye Xu and published by . This book was released on 2009 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil respiration (RS) accounts for up to 60%~80% of forest ecosystem respiration. Forest RS variability can have a great effect on the global carbon balance. Harvesting timber for human needs is prevalent all over the world, but its long term effect on RS as well as its temporal variability is still unclear. This study focused on the interannual variability of RS and its controlling factors in oak forests with different timber harvest management practices in the Missouri Ozark Forest Ecosystem Project (MOFEP). Interannual RS, soil temperature (TS), and soil moisture (MS) were measured to investigate the long term (5-year) variability of RS and its controlling factors in forests subjected to different harvesting methods. The three MOFEP treatments used in this study included: control no-harvest (NHM), even-aged clear-cut harvest (EAM), and uneven-aged single-tree harvest (UAM). Soil properties, including soil ammonium content, nitrate content, microbial biomass, total organic carbon and pH were also tested to assess the treatment effects. My results showed that, seasonally, RS in all treatments increased from January to July and decreased afterwards, sharing a similar seasonal trend in TS. Interannually, total summer precipitation (PPTS) was highly related to summer mean RS in EAM and UAM but not NHM. The interannual comparison demonstrated that overall RS in EAM and UAM were higher than that in NHM in wet years and lower in dry years, but the differences were only statistically significant in 2007 when the area suffered a severe summer drought. The more stable interannual RS suggested that NHM are more resistant to disturbance than the harvested treatments. TS was the best predictor of RS, and a threshold existed in the relationship between TS and RS (~23°C). RS increased exponentially with TS when TS was lower than this threshold, but decreased when TS was higher than this threshold. The TS threshold changed monthly from May to August, with the lowest threshold in May (~19°C) and the highest in July (~26°C) with stable monthly MS, suggesting that the monthly threshold is controlled by substrate supply from aboveground plant photosynthesis. Moreover, the threshold also changes annually, with RS in 2007 the lowest (~20°C) and 2008 the highest (~25°C). As a consequence, the low MS and depleted substrate supply is probably the reason for this TS threshold. The three treatments also had different TS thresholds for RS, but these differences were trivial. The annual Q10 values for each treatment showed that over the five years, NHM had the highest Q10 and UAM had the lowest. Tests of soil properties among treatments showed no significant differences except in pH, suggesting that soil properties had largely recovered from harvesting if it was changed by harvesting disturbance. This study contradicts my hypothesis that RS and its variability differs among treatments after several years post-harvest, but support the hypothesis that the biophysical regulations of soil respiration at the three treatments were different.
