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Michael F Allen - One of the best experts on this subject based on the ideXlab platform.
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Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory.
The New phytologist, 2013Co-Authors: Rebecca R. Hernandez, Michael F AllenAbstract:Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in Soils. However, their basic biology, including their activity throughout a 24-h day : night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the circadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with Soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying Soil carbon sequestration, nutrient cycling and host plant success.
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Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory
2013Co-Authors: Rebecca R. Hern, Michael F Allen, Rebecca R. HernandezAbstract:plant–fungus, Soil organic matter, Soil temperature, symbiosis. Summary Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in Soils. However, their basic biology, including their activity throughout a 24-h day: night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the cir-cadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with Soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying Soil carbon sequestration, nutrient cycling and host plant success
Yooeun Chae - One of the best experts on this subject based on the ideXlab platform.
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ecological hazard assessment of methyl ethyl ketone using the species sensitivity distribution approach in a Soil Ecosystem
Journal of Hazardous Materials, 2018Co-Authors: Yooeun Chae, Rongxue Cui, Jongmin MoonAbstract:Abstract Methyl ethyl ketone (MEK) is a common and widely used industrial solvent. However, few studies have investigated its toxicity, or its effects as a contaminant in Soil Ecosystems. In this study, acute and chronic toxicity data for MEK were generated, and ecological risk based on a species sensitivity distribution was assessed. Seven Soil organisms from six taxonomic groups were used for acute toxicity tests and five Soil organisms from four taxonomic groups were used for chronic toxicity tests. Acute and chronic Soil HC5 (hazardous concentration for 5% of species) values for MEK were estimated as 53.04 and 2.593 mg MEK/kg dry Soil, respectively. This is the first study to conduct battery testing for MEK; it specifies hazardous concentrations, warns of the need for accident preparedness, and points to serious potential hazards of MEK at various levels of the Soil Ecosystem which can translate into greater environmental damage with implications for human health. The specific sensitivity levels determined may serve as a benchmark for establishing Soil standards and strategies for Ecosystem protection in the face of accidental contamination.
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current research trends on plastic pollution and ecological impacts on the Soil Ecosystem a review
Environmental Pollution, 2018Co-Authors: Yooeun ChaeAbstract:Plastic pollution in the environment is currently receiving worldwide attention. Improper dumping of disused or abandoned plastic wastes leads to contamination of the environment. In particular, the disposal of municipal wastewater effluent, sewage sludge landfill, and plastic mulch from agricultural activities is a serious issue and of major concern regarding Soil pollution. Compared to plastic pollution in the marine and freshwater Ecosystems, that in the Soil Ecosystem has been relatively neglected. In this study, we discussed plastic pollution in the Soil environment and investigated research on the effects of plastic wastes, especially microplastics, on the Soil Ecosystem. We found that earthworms have been predominantly used as the test species in investigating the effects of Soil plastic pollution on organisms. Therefore, further research investigating the effects of plastic on other species models (invertebrates, plants, microorganisms, and insects) are required to understand the effects of plastic pollution on the overall Soil Ecosystem. In addition, we suggest other perspectives for future studies on plastic pollution and Soil ecotoxicity of plastics wastes, providing a direction for such research.
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exoenzyme activity in contaminated Soils before and after Soil washing s glucosidase activity as a biological indicator of Soil health
Ecotoxicology and Environmental Safety, 2017Co-Authors: Yooeun Chae, Rongxue Cui, Shin Woong Kim, Seungwoo JeongAbstract:It is essential to remediate or amend Soils contaminated with various heavy metals or pollutants so that the Soils may be used again safely. Verifying that the remediated or amended Soils meet Soil quality standards is an important part of the process. We estimated the activity levels of eight Soil exoenzymes (acid phosphatase, arylsulfatase, catalase, dehydrogenase, fluorescein diacetate hydrolase, protease, urease, and s-glucosidase) in contaminated and remediated Soils from two sites near a non-ferrous metal smelter, using colorimetric and titrimetric determination methods. Our results provided the levels of activity of Soil exoenzymes that indicate Soil health. Most enzymes showed lower activity levels in remediated Soils than in contaminated Soils, with the exception of protease and urease, which showed higher activity after remediation in some Soils, perhaps due to the limited nutrients available in remediated Soils. Soil exoenzymes showed significantly higher activity in Soils from one of the sites than from the other, due to improper conditions at the second site, including high pH, poor nutrient levels, and a high proportion of sand in the latter Soil. Principal component analysis revealed that s-glucosidase was the best indicator of Soil Ecosystem health, among the enzymes evaluated. We recommend using s-glucosidase enzyme activity as a prior indicator in estimating Soil Ecosystem health.
Young Ho Kim - One of the best experts on this subject based on the ideXlab platform.
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Effects of heavy metal contamination from an abandoned mine on nematode community structure as an indicator of Soil Ecosystem health
Applied Soil Ecology, 2011Co-Authors: Byeong-yong Park, Hee-myong Ro, Jae-kook Lee, Young Ho KimAbstract:Soil nematode community structure reflects Soil Ecosystem health and is influenced by the Soil environment directly and/or indirectly by affecting the Soil micro-flora and fauna that they graze. In this study, ecological indices for Soil nematode community structure and microbial populations in Soils contaminated with mine drainage (CS) from an abandoned mine and of a nearby non-contaminated area (NC) were examined during the seven seasons from July 2007 through December 2008 to reveal influences of mine drainage (especially heavy metals) on the Soil nematode community structure. Of the Soil physicochemical characteristics measured, nutritional properties such as organic matter content, nitrogen content, and soluble cations were not significantly different between CS and NC; however, significant differences were detected in pH, electrical conductivity (EC), available phosphorus (av.P2O5), and most strikingly, the concentrations of heavy metals such as Cd, Pb, Zn, and Ni. Nematodes were less abundant in CS than in NC, especially for long-living persistor-type nematodes. Comparison of ecological indices between CS and NC indicates that abundance, maturity, richness, and diversity of the Soil nematode community were decreased in CS Soil, indicating that Soil health and function were adversely affected. Of the weighted-Soil food-web indices, the structural index (SI) of the Soil nematode community was significantly lower in CS than in NC, while no significant difference in the enrichment index (EI) was observed between CS and NC, suggesting that the heavy metal contamination may have disturbed the Soil Ecosystem by suppressing biological activity. Seasonal changes in the ecological indices during the study period showed that the discrepancies between CS and NC persisted throughout most of the seasons, suggesting that the effect of mine drainage (heavy metal) contamination on nematode community structure may be little influenced by seasonal changes in environmental conditions.
Rebecca R. Hernandez - One of the best experts on this subject based on the ideXlab platform.
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Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory.
The New phytologist, 2013Co-Authors: Rebecca R. Hernandez, Michael F AllenAbstract:Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in Soils. However, their basic biology, including their activity throughout a 24-h day : night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the circadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with Soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying Soil carbon sequestration, nutrient cycling and host plant success.
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Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory
2013Co-Authors: Rebecca R. Hern, Michael F Allen, Rebecca R. HernandezAbstract:plant–fungus, Soil organic matter, Soil temperature, symbiosis. Summary Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in Soils. However, their basic biology, including their activity throughout a 24-h day: night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the cir-cadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with Soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying Soil carbon sequestration, nutrient cycling and host plant success
J E Barrett - One of the best experts on this subject based on the ideXlab platform.
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unimodal productivity diversity relationships among bacterial communities in a simple polar Soil Ecosystem
Environmental Microbiology, 2019Co-Authors: Kevin M Geyer, J E BarrettAbstract:Unlike other macroecological principles, relationships between productivity and diversity have not been effectively tested for microbial communities. Here we describe an experiment in which the availability of resources to Soil bacterial communities was manipulated in a model system, the McMurdo Dry Valleys of Antarctica. Mannitol additions were used to simulate a productivity gradient such that a response in bacterial biomass production, taxonomic diversity and functioning (e.g., enzyme activity) were induced. Resource amendment induced a positive linear response in microbial productivity (P < 0.001) but a unimodal (hump-shaped) response in microbial diversity at multiple taxonomic scales (P = 0.035). Putative oligotrophic (e.g., phyla Nitrospirae and Cyanobacteria) and copiotrophic (e.g., phylum Proteobacteria) taxa were apparent through substantial community turnover along the resource gradient. Soil enzyme activity was inversely related to bacterial biomass but positively related to diversity, suggesting the latter may be a stronger control over enzyme-mediated decomposition. The mechanisms behind this pattern are consistent with macroecological theory of a shift from environmental (e.g., stress tolerance) to biotic (e.g., competition) drivers with increasing resource availability. This evidence is among the first of its kind to document a significant unimodal productivity-diversity relationship for Soil bacteria.
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decline in a dominant invertebrate species contributes to altered carbon cycling in a low diversity Soil Ecosystem
Global Change Biology, 2008Co-Authors: J E Barrett, Ross A Virginia, Diana H Wall, Byron J AdamsAbstract:Low-diversity Ecosystems cover large portions of the Earth’s land surface, yet studies of climate change on Ecosystem functioning typically focus on temperate Ecosystems, where diversity is high and the effects of individual species on Ecosystem functioning are difficult to determine. We show that a climate-induced decline of an invertebrate species in a low-diversity Ecosystem could contribute to significant changes in carbon (C) cycling. Recent climate variability in the McMurdo Dry Valleys of Antarctica is associated with changes in hydrology, biological productivity, and community composition of terrestrial and aquatic Ecosystems. One of the greatest changes documented in the dry valleys is a 65% decrease in the abundance of the dominant Soil invertebrate (Scottnema lindsayae, Nematoda) between 1993 and 2005, illustrating sensitivity of biota in this Ecosystem to small changes in temperature. Globally, such declines are expected to have significant influences over Ecosystem processes such as C cycling. To determine the implications of this climate-induced decline in nematode abundance on Soil C cycling we followed the fate of a 13 C tracer added to Soils in Taylor Valley, Antarctica. Carbon assimilation by the dry valley nematode community contributed significantly to Soil C cycling (2–7% of the heterotrophic C flux). Thus, the influence of a climate-induced decline in abundance of a dominant species may have a significant effect on Ecosystem functioning in a low-diversity Ecosystem.
