20141229

Author: Unger, S. Maguas, C. Pereira, J. S. David, T. S. Werner, C.
Year : 2010
Title: The influence of precipitation pulses on soil respiration - Assessing the "Birch effect" by stable carbon isotopes
Journal : Soil Biology & Biochemistry
Comment : Current hypotheses indicate that the “Birch” pulse is caused by rapidly increased respiration and mineralization rates in response to changing moisture conditions but the underlying mechanisms are still unclear. They continuously monitored CO2-fluxes along with their isotopic compositions before, during and after the irrigation. 13C signatures of the first CO2-efflux burst, occurring immediately after rewetting, fit the hypothesis that the “Birch” pulse is caused by the rapid mineralization of either dead microbial biomass or osmoregulatory substances released by soil microorganisms in response to hypo-osmotic stress in order to avoid celllyses. The response of soil CO2-efflux to rewetting was smaller under mild (May) than under severe drought (August) and isotopic compositions indicated a larger contribution of anaplerotic carbon uptake with increasing soil desiccation.

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20131218

Author  : Edmondson, J. L. Davies, Z. G. McHugh, N. Gaston, K. J. Leake, J. R. Year  : 2012 Title  : Organic carbon hidden in urban ecosystems Journal  : Scientific Reports Comment   : To date, the total quantity of OC stored in urban soils (under both impervious surfaces and greenspaces), together with that in above-ground vegetation, has never been systematically measured.  They report the first city-wide organic carbon (OC) budget for vegetation and soils, including under impervious surfaces. The majority of OC (82%) was held in soils, with 13% found under impervious surfaces, and 18% stored in vegetation.
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The concurrent decline of soil lead and children’s blood lead in New Orleans

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The concurrent decline of soil lead and children’s blood lead in New Orleans Howard W. Mielke ,  Christopher R. Gonzales ,  Eric T. Powell ,  Mark A. S. Laidlaw ,  Kenneth J. Berry ,  Paul W. Mielke  Jr. , and  Sara Perl Egendorf PNAS  first published October 14, 2019  https://doi.org/10.1073/pnas.1906092116 Significance The inextricable link between topsoil lead (Pb) and children’s blood lead (BPb) has not been widely accepted. Pb is associated with multiple health adversities. Urban residents are at risk from exposure to legacy Pb dust in topsoil resulting from smelting, industrial discharges, leaded gasoline emissions, leaded paint, and incineration. In New Orleans, topsoil median Pb decreased in ∼15 y from 99 mg/kg to 54 mg/kg, or ∼2.4 mg⋅kg⋅y −1 . In ∼12 y, children’s median BPb declined from 3.6 μg/dL to 1.3 μg/dL, or ∼0.2 μg⋅dL⋅y −1 . We argue that depletion of topsoil Pb is an important factor in the continuous dec...
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20140731

Author  : Chen, Y. J. Day, S. D. Shrestha, R. K. Strahm, B. D. Wiseman, P. E. Year  : 2014 Title  : Influence of urban land development and soil rehabilitation on soil-atmosphere greenhouse gas fluxes Journal  : Geoderma Comment   : Typical land development practices did not increase global warming potential (GWP) when compared to undeveloped land. Post-development soil rehabilitation, however, resulted in greater GWP than both undisturbed soils and those subjected to typical development practices driven primarily by increased CO2 efflux.
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