The purpose of this study was to determine the effects of soil temperature, soil moisture, redox potential (Eh) and soil organic matter (SOM) on the total gaseous mercury (TGM) concentrations in background soils. Our measurements were made in a grass field and deciduous forest at the Piney Reservoir Ambient Air Monitoring Station (PRAAMS) in Garrett County, Maryland. Three plots in each area were sampled every third week from July 2009 to June 2010 at the Oe-A soil horizon interface, the A-E soil horizon interface, and 5 and 10 cm into the E soil horizon. The mean soil TGM concentration for all depths in the forest (2.3 ± 2.2 ng m(-3)) was significantly higher than the mean soil TGM concentration in the grass field (1.5 ± 1.9 ng m(-3)). Soil TGM at all depths was most strongly and consistently correlated to soil temperature. The soil TGM concentrations were highest and most variable at the forest Oe-A soil horizon interface (4.1 ± 2.0 ng m(-3)), ranging from 1.5 to 8.4 ng m(-3). This soil horizon interface had 11 to 26% more SOM and the soil Eh was 100 to 400 mV lower than the other soil depths. Our results suggest that soil temperature, soil Eh and SOM are significant factors affecting TGM concentrations in forest soils. Future studies of TGM dynamics in background soils may benefit from closely monitoring the organic soil horizon.
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http://dx.doi.org/10.1016/j.scitotenv.2011.12.068 | DOI Listing |
Sci Rep
December 2024
School of Health and Life Sciences, Teesside University, Middlesbrough, UK.
Outdoor microcosms, metabarcoding with next-generation sequencing of the 16S rRNA bacterial gene, total body score (TBS) and physicochemical analyses were used to monitor Mus musculus decomposition aboveground (A) and in the subsurface (S), and compared to soil-only controls (C). As determined by MaAsLin2 analysis, significant shifts in bacterial communities at 30 cm depths within the A, S and C treatments distinguished control from experimental soils, and between aboveground and subsurface deposition, demonstrating the potential for gravesoil discrimination during the first 90 days. For example, Dokdonella (p = 0.
View Article and Find Full Text PDFBMC Plant Biol
December 2024
Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 190, Lomma, SE-234 22, Sweden.
Background: Aphanomyces root rot is one of the most severe diseases in sugar beet (Beta vulgaris L.), resulting in drastic losses in sugar yield and plant degeneration. The causal agent is the soil-borne pathogen Aphanomyces cochlioides, a phytopathogenic oomycete able to infect sugar beet roots from the seedling stage until harvest.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Horizons Regional Council, Private Bag 11 025, Palmerston North, 4442, New Zealand.
Mitigating the impacts of agricultural nutrients (nitrogen and phosphorus) on water quality requires a clear understanding of their transport pathways and transformation processes from land to receiving waters. For nitrate, which is subject to subsurface denitrification, it is therefore important to assess the spatial variability and temporal stability of groundwater redox conditions, as nitrate reduction typically occurs in reducing conditions. This paper presents a robust assessment of a large groundwater quality data set collected across New Zealand landscapes, develops methods to impute missing groundwater redox-sensitive variables and characterises the spatial variability and temporal stability of groundwater redox conditions against relevant landscape hydrogeochemical characteristics.
View Article and Find Full Text PDFPNAS Nexus
December 2024
CRETUS, Non-Linear Physics Group, Faculty of Physics, Universidade de Santiago de Compostela, Galicia 15782, Spain.
In the vegetation root zone, infiltration () parts in two directions with distinct Earth-system functions. One goes up as evapotranspiration ( + ), returning to the atmosphere (short-circuiting) and affecting short-term weather/climate and the carbon cycle. The other goes down as deep drainage (), flushing the regolith, mobilizing nutrients/contaminates and dissolved minerals into aquifers and rivers, eventually reaching the ocean (long-circuiting) thus regulating global biogeochemical cycles and long-term climate.
View Article and Find Full Text PDFPlant Cell Environ
December 2024
Institute of Plant and Microbial Biology, University of Zürich, Zürich, Switzerland.
Plants exude a wide variety of compounds into the rhizosphere, modulating soil functioning and diversity. The number of studies investigating exudation has exponentially increased over the past decades. Yet, the high inter-study variability of the results is slowing down our understanding of root-soil interactions.
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