The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
Peter B Adler - One of the best experts on this subject based on the ideXlab platform.
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Climate change, Snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens.
Aob Plants, 2019Co-Authors: Danielle M. Smull, Nicole Pendleton, Andrew R. Kleinhesselink, Peter B AdlerAbstract:Climate change is reducing the depth and duration of winter Snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of Snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced Snowpack might promote B. tectorum population growth by decreasing damage from Snow Molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early Snowmelt and either fungicide addition or Snow mold infection of B. tectorum. The greenhouse experiment confirmed that the Snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early Snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and Snow mold inoculation had no effect on survival. We did find interactive effects of Snowmelt and fungal treatments on B. tectorum seed production: with ambient Snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early Snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the Snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced Snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.
Danielle M. Smull - One of the best experts on this subject based on the ideXlab platform.
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Climate change, Snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens.
Aob Plants, 2019Co-Authors: Danielle M. Smull, Nicole Pendleton, Andrew R. Kleinhesselink, Peter B AdlerAbstract:Climate change is reducing the depth and duration of winter Snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of Snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced Snowpack might promote B. tectorum population growth by decreasing damage from Snow Molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early Snowmelt and either fungicide addition or Snow mold infection of B. tectorum. The greenhouse experiment confirmed that the Snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early Snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and Snow mold inoculation had no effect on survival. We did find interactive effects of Snowmelt and fungal treatments on B. tectorum seed production: with ambient Snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early Snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the Snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced Snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.
Steven K Schmidt - One of the best experts on this subject based on the ideXlab platform.
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exponential growth of Snow Molds at sub zero temperatures an explanation for high beneath Snow respiration rates and q 10 values
Biogeochemistry, 2009Co-Authors: Steven K Schmidt, K L Wilson, Russell K Monson, David A LipsonAbstract:Numerous studies have demonstrated exceptionally high temperature sensitivity of the beneath-Snow respiratory flux in cold-winter ecosystems. The most common, but still untested, explanation for this high sensitivity is a physical one based on the observation that water availability in soils increases exponentially as soils warm from −3 to 0°C. Here, we present evidence for a biological hypothesis to explain exponential kinetics and high Q 10 values as beneath-Snow soils warm from −3 to 0°C during the early spring in a high-elevation subalpine forest. First, we show that some of the dominant organisms of the beneath-Snow microbial community, “Snow Molds”, exhibit robust exponential growth at temperatures from −3 to −0.3°C. Second, Q 10 values based on growth rates across the temperature range of −2 to −0.3°C for these Snow Molds vary from 22 to 330. Third, we derive an analytical equation that combines the relative contributions of microbial growth and microbial metabolism to the temperature sensitivity of respiration. Finally, we use this equation to show that with only moderate Snow mold growth (several generations), the combined sensitivities of growth and metabolism to small changes in beneath-Snow soil temperature, create a double exponential in the Q 10 function that may explain the extremely high (~1 × 106) Q 10 values observed in past studies. Our biological explanation for high Q 10 levels is supported by several independent studies that have demonstrated build up of microbial biomass under the Snow as temperatures warm from −2 to 0°C.
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phylogeny and ecophysiology of opportunistic Snow Molds from a subalpine forest ecosystem
Microbial Ecology, 2008Co-Authors: Steven K Schmidt, K L Wilson, A F Meyer, M M Gebauer, Andrew J KingAbstract:Mats of coenocytic “Snow Molds” are commonly observed covering the soil and litter of alpine and subalpine areas immediately following Snow melt. Here, we describe the phylogenetic placement, growth rates, and metabolic potential of cold-adapted fungi from under-Snow mats in the subalpine forests of Colorado. SSU rDNA sequencing revealed that these fungi belong to the zygomycete orders Mucorales and Mortierellales. All of the isolates could grow at temperatures observed under the Snow at our sites (0°C and −2°C) but were unable to grow at temperatures above 25°C and were unable to grow anaerobically. Growth rates for these fungi were very high at −2°C, approximately an order of magnitude faster than previously studied cold-tolerant fungi from Antarctic soils. Given the rapid aerobic growth of these fungi at low temperatures, we propose that they are uniquely adapted to take advantage of the flush of nutrient that occurs at the soil–Snow interface beneath late winter Snow packs. In addition, extracellular enzyme production was relatively high for the Mucorales, but quite low for the Mortierellales, perhaps indicating some niche separation between these fungi beneath the late winter Snow pack.
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ORIGINAL ARTICLE Phylogeny and Ecophysiology of Opportunistic “Snow Molds” from a Subalpine Forest Ecosystem
2007Co-Authors: Steven K Schmidt, K L Wilson, A F Meyer, M M Gebauer, Andrew J KingAbstract:Abstract Mats of coenocytic “Snow Molds ” are commonly observed covering the soil and litter of alpine and subalpine areas immediately following Snow melt. Here, we describe the phylogenetic placement, growth rates, and metabolic potential of cold-adapted fungi from under-Snow mats in the subalpine forests of Colorado. SSU rDNA sequencing revealed that these fungi belong to the zygomycete orders Mucorales and Mortierellales. All of the isolates could grow at temperatures observed under the Snow at our sites (0°C and −2°C) but were unable to grow at temperatures above 25°C and were unable to grow anaerobically. Growth rates for these fungi were very high at −2°C, approximately an order of magnitude faster than previously studied cold-tolerant fungi from Antarctic soils. Given the rapid aerobic growth of these fungi at low temperatures, we propose that they are uniquely adapted to take advantage of the flush of nutrient that occurs at the soil–Snow interface beneath late winter Snow packs. In addition, extracellular enzyme produc-tion was relatively high for the Mucorales, but quite low for the Mortierellales, perhaps indicating some niche separation between these fungi beneath the late winter Snow pack
Andrew R. Kleinhesselink - One of the best experts on this subject based on the ideXlab platform.
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Climate change, Snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens.
Aob Plants, 2019Co-Authors: Danielle M. Smull, Nicole Pendleton, Andrew R. Kleinhesselink, Peter B AdlerAbstract:Climate change is reducing the depth and duration of winter Snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of Snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced Snowpack might promote B. tectorum population growth by decreasing damage from Snow Molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early Snowmelt and either fungicide addition or Snow mold infection of B. tectorum. The greenhouse experiment confirmed that the Snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early Snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and Snow mold inoculation had no effect on survival. We did find interactive effects of Snowmelt and fungal treatments on B. tectorum seed production: with ambient Snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early Snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the Snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced Snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.
Nicole Pendleton - One of the best experts on this subject based on the ideXlab platform.
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Climate change, Snow mold and the Bromus tectorum invasion: mixed evidence for release from cold weather pathogens.
Aob Plants, 2019Co-Authors: Danielle M. Smull, Nicole Pendleton, Andrew R. Kleinhesselink, Peter B AdlerAbstract:Climate change is reducing the depth and duration of winter Snowpack, leading to dramatic changes in the soil environment with potentially important ecological consequences. Previous experiments in the Intermountain West of North America indicated that loss of Snowpack increases survival and population growth rates of the invasive annual grass Bromus tectorum; however, the underlying mechanism is unknown. We hypothesized that reduced Snowpack might promote B. tectorum population growth by decreasing damage from Snow Molds, a group of subnivean fungal pathogens. To test this hypothesis, we conducted greenhouse and field experiments to investigate the interaction between early Snowmelt and either fungicide addition or Snow mold infection of B. tectorum. The greenhouse experiment confirmed that the Snow mold Microdochium nivale can cause mortality of B. tectorum seedlings. In the field experiment, early Snowmelt and fungicide application both increased B. tectorum survival, but their effects did not interact, and Snow mold inoculation had no effect on survival. We did find interactive effects of Snowmelt and fungal treatments on B. tectorum seed production: with ambient Snowpack, M. nivale inoculation reduced seed production and fungicide increased it, whereas in the early Snowmelt treatment seed production was high regardless of fungal treatment. However, treatment effects on seed production did not translate directly to overall population growth, which did not respond to the Snow melt by fungal treatment interaction. Based on our mixed results, the hypothesis that reduced Snowpack may increase B. tectorum fitness by limiting the effects of plant pathogens deserves further investigation.