ORCID Profile
0000-0001-8270-9387
Current Organisation
US Geological Survey
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Publisher: Wiley
Date: 26-03-2021
DOI: 10.1111/GCB.15580
Publisher: Elsevier BV
Date: 08-2011
Publisher: Wiley
Date: 16-10-2020
DOI: 10.1111/GCB.15365
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.ENVPOL.2015.07.002
Abstract: We investigated effects of Ag2S engineered nanomaterials (ENMs), polyvinylpyrrolidone (PVP) coated Ag ENMs (PVP-Ag), and Ag(+) on arbuscular mycorrhizal fungi (AMF), their colonization of tomato (Solanum lycopersicum), and overall microbial community structure in biosolids-amended soil. Concentration-dependent uptake was measured in all treatments. Plants exposed to 100 mg kg(-1) PVP-Ag ENMs and 100 mg kg(-1) Ag(+) exhibited reduced biomass and greatly reduced mycorrhizal colonization. Bacteria, actinomycetes and fungi were inhibited by all treatment classes, with the largest reductions measured in 100 mg kg(-1) PVP-Ag ENMs and 100 mg kg(-1) Ag(+). Overall, Ag2S ENMs were less toxic to plants, less disruptive to plant-mycorrhizal symbiosis, and less inhibitory to the soil microbial community than PVP-Ag ENMs or Ag(+). However, significant effects were observed at 1 mg kg(-1) Ag2S ENMs, suggesting that the potential exists for microbial communities and the ecosystem services they provide to be disrupted by environmentally relevant concentrations of Ag2S ENMs.
Publisher: American Geophysical Union (AGU)
Date: 06-2016
DOI: 10.1002/2016JG003347
Publisher: Elsevier BV
Date: 12-2014
Publisher: Research Square Platform LLC
Date: 02-05-2023
DOI: 10.21203/RS.3.RS-2838519/V1
Abstract: Background and Aims: Re-vegetation of contaminated and disturbed landscapes can reduce the transport of toxic elements while improving soil fertility. This study evaluated whether the planting of a perennial grass with diazotrophic microbial endophytes and municipal waste compost—alone and in combination—improved phytostabilization of potentially toxic trace elements in dolomite-amended tailings from a historically mined polymetallic mineral deposit. Methods We grew Bouteloua curtipendula seedlings in tailings with hazardous concentrations of As, Cd, Pb, Mn, and Zn. We evaluated how plant growth, organic matter accumulation, and minor and trace element mobilization responded to microbial endophyte and organic amendments. Results Although most of the added endophytes were not uniquely identified, the best plant growth and fertility outcomes were achieved with a combination of amendments: dolomite to reduce acidity, a compost topdressing to accumulate nitrogen in the tailings, and a mixed consortium endophyte seed coating to synergistically increase organic carbon and grass biomass yields. Combining amendments also improved phytostabilization: compost reduced the shoot forage toxicity of B. curtipendula seedlings without reducing phytostabilized contaminant yields in the rhizosphere, while endophyte inoculated grass marginally reduced total and water-extractable concentrations of toxic trace elements through enhanced mobilization. Conclusion The most effective means of reclaiming these acidic, polymetallic tailings is with a simultaneous dolomite, compost, and endophyte seed treatment.
Publisher: American Geophysical Union (AGU)
Date: 06-2022
DOI: 10.1029/2022JG006807
Abstract: The potential for carbon sequestration in coastal wetlands is high due to protection of carbon (C) in flooded soils. However, excessive flooding can result in the conversion of the vegetated wetland to open water. This transition results in the loss of wetland habitat in addition to the potential loss of soil carbon. Thus, in areas experiencing rapid wetland submergence, such as the Mississippi River Delta, coastal wetlands could become a significant source of carbon emissions if land loss is not mitigated. To accurately assess the capacity of wetlands to store (or emit) carbon in dynamic environments, it is critical to understand the fate of soil carbon following the transition from vegetated wetland to open water. We developed a simple soil carbon model representing soil depths to 1 m using the data collected from a Louisiana coastal salt marsh in the Mississippi River Deltaic Plain to predict soil carbon density and stock following the transition from a vegetated salt marsh to an open water pond. While immediate effects of ponding on the distribution of carbon within the 1‐m soil profile were apparent, there were no effects of ponding on the overall, integrated, carbon stocks 14 years, following wetland submergence. Rather, the model predicts that soil carbon losses in the first meter will be realized over long periods of time (∼200 years) due to changes in the source of carbon (biomass vs. mineral sediment) with minimal losses through mineralization.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 12-2015
Publisher: Copernicus GmbH
Date: 18-08-2016
DOI: 10.5194/SOIL-2016-54
Abstract: Abstract. Devising agricultural management schemes that enhance food security and soil carbon levels is a high priority for many nations. However, the coupling between agricultural productivity, soil carbon stocks and organic matter turnover rates is still unclear. Archived soil s les from four decades of a long-term crop rotation trial were analysed for soil organic matter (SOM) cycling relevant properties: C and N content, bulk composition by NMR spectroscopy, amino sugar content, short term C bioavailability assays, and long-term C turnover rates by modeling the incorporation of the bomb-spike in atmospheric 14C into the soil. After 40 years under consistent management, topsoil carbon stocks ranged from 14 to 33 Mg C ha−1 and were linearly related to the mean productivity of each treatment. Measurements of SOM composition demonstrated increasing amounts of plant- and microbially-derived SOM along the productivity gradient. Under two modelling scenarios, radiocarbon data indicated overall SOM turnover time decreased from 40 to 13 years with increasing productivity twice the rate of decline predicted from simple steady-state models or static three-pool decay rates of measured C pool distributions. Similarly, the half-life of synthetic root exudates decreased from 30.4 to 21.5 hours with increasing productivity indicating accelerated microbial activity. These findings suggest that there is a direct feedback between accelerated biological activity, carbon cycling rates and rates of carbon stabilization with important implications for how SOM dynamics are represented in models.
Publisher: Elsevier BV
Date: 02-2016
Publisher: Elsevier BV
Date: 11-2012
Publisher: Elsevier BV
Date: 02-2013
Publisher: Wiley
Date: 26-08-2021
DOI: 10.1111/GCB.15850
Abstract: Here we respond to Baveye and colleagues' recent critique of our PROMISE model, describing how this new framework significantly advances our understanding of soil spatial heterogeneity and its influence on organic matter transformations.
Publisher: Wiley
Date: 18-02-2022
Abstract: Microbial necromass is a large, dynamic and persistent component of soil organic carbon, the dominant terrestrial carbon pool. Quantification of necromass carbon stocks and its susceptibility to global change is becoming standard practice in soil carbon research. However, the typical proxies used for necromass carbon do not reveal the dynamic nature of necromass carbon flows and transformations within soil that ultimately determine necromass persistence. In this review, we define and deconstruct four stages of the necromass continuum: production, recycling, stabilization and destabilization. Current understanding of necromass dynamics is described for each continuum stage. We highlight recent advances, methodological limitations and knowledge gaps which need to be addressed to determine necromass pool sizes and transformations. We discuss the dominant controls on necromass process rates and aspects of soil microscale structure including biofilms and food web interactions. The relative importance of each stage of the continuum is then compared in contrasting ecosystems and for climate change drivers. From the perspective of the continuum, we draw three conclusions to inform future research. First, controls on necromass persistence are more clearly defined when viewed through the lens of the continuum second, destabilization is the least understood stage of the continuum with recycling also poorly evidenced outside of a few ecosystems and third, the response of necromass process rates to climate change is unresolved for most continuum stages and ecosystems. Future mechanistic research focused on the role of biotic and abiotic soil microscale structure in determining necromass process rates and the relative importance of organo–mineral and organo–organo interactions can inform necromass persistence in different climate change scenarios. Our review demonstrates that deconstructing the necromass continuum is key to predicting the vulnerability and persistence of necromass carbon in a changing world. Read the free Plain Language Summary for this article on the Journal blog.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Copernicus GmbH
Date: 04-01-2017
Abstract: Abstract. Devising agricultural management schemes that enhance food security and soil carbon levels is a high priority for many nations. However, the coupling between agricultural productivity, soil carbon stocks and organic matter turnover rates is still unclear. Archived soil s les from four decades of a long-term crop rotation trial were analyzed for soil organic matter (SOM) cycling-relevant properties: C and N content, bulk composition by nuclear magnetic resonance (NMR) spectroscopy, amino sugar content, short-term C bioavailability assays, and long-term C turnover rates by modeling the incorporation of the bomb spike in atmospheric 14C into the soil. After 40 years under consistent management, topsoil carbon stocks ranged from 14 to 33 Mg C ha−1 and were linearly related to the mean productivity of each treatment. Measurements of SOM composition demonstrated increasing amounts of plant- and microbially derived SOM along the productivity gradient. Under two modeling scenarios, radiocarbon data indicated overall SOM turnover time decreased from 40 to 13 years with increasing productivity – twice the rate of decline predicted from simple steady-state models or static three-pool decay rates of measured C pool distributions. Similarly, the half-life of synthetic root exudates decreased from 30.4 to 21.5 h with increasing productivity, indicating accelerated microbial activity. These findings suggest that there is a direct feedback between accelerated biological activity, carbon cycling rates and rates of carbon stabilization with important implications for how SOM dynamics are represented in models.
Publisher: CSIRO Publishing
Date: 11-02-2021
DOI: 10.1071/SR20269
Abstract: The stock of organic carbon contained within a soil represents the balance between inputs and losses. Inputs are defined by the ability of vegetation to capture and retain carbon dioxide, effects that management practices have on the proportion of captured carbon that is added to soil and the application organic amendments. The proportion of organic amendment carbon retained is defined by its rate of mineralisation. In this study, the rate of carbon mineralisation from 85 different potential soil organic amendments (composts, manures, plant residues and biosolids) was quantified under controlled environmental conditions over a 547 day incubation period. The composition of each organic amendment was quantified using nuclear magnetic resonance and mid- and near-infrared spectroscopies. Cumulative mineralisation of organic carbon from the amendments was fitted to a two-pool exponential model. Multivariate chemometric algorithms were derived to allow the size of the fast and slow cycling pools of carbon to be predicted from the acquired spectroscopic data. However, the fast and slow decomposition rate constants could not be predicted suggesting that prediction of the residence time of organic amendment carbon in soil would likely require additional information related to soil type, environmental conditions, and management practices in use at the site of application.
Publisher: Wiley
Date: 20-02-2015
Publisher: Informa UK Limited
Date: 30-08-2022
Publisher: Springer Science and Business Media LLC
Date: 05-08-2012
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 22-02-2021
No related grants have been discovered for Courtney Creamer.