Root responses of flood-tolerant and flood-sensitive tree species to soil redox conditions

Trees ◽  
1991 ◽  
Vol 5 (3) ◽  
Author(s):  
S.R. Pezeshki
Keyword(s):  
Tree Species ◽  
Redox Conditions ◽  
Soil Redox ◽  
Root Responses

scholarly journals Leaf gas exchange and growth of flood-tolerant and flood-sensitive tree species under low soil redox conditions

1996 ◽  
Vol 16 (4) ◽  
pp. 453-458 ◽  
Author(s):  
S. R. Pezeshki ◽  
J. H. Pardue ◽  
R. D. DeLaune
Keyword(s):  
Gas Exchange ◽  
Tree Species ◽  
Leaf Gas Exchange ◽  
Redox Conditions ◽  
Soil Redox

Influence of soil redox conditions on oxidation of biotite

Clay Minerals ◽  
1986 ◽  
Vol 21 (2) ◽  
pp. 149-157 ◽  
Author(s):  
S. Bouda ◽  
K. P. Isaac
Keyword(s):  
Mössbauer Spectroscopy ◽  
Soil Profile ◽  
Mossbauer Spectroscopy ◽  
Redox Conditions ◽  
Soil Profiles ◽  
Moderate Degree ◽  
Soil Redox ◽  
Mößbauer Spectroscopy

AbstractBiotites from three peaty gleyed podzol soil profiles on ranite bedrock were examined to investigate the oxidation of the octahedral Fe during weathering. Oxidation of these biotites as determined by Mössbauer spectroscopy shows a good correlation with the in situ measured soil Eh values of the sampled horizons. In every soil profile the highest Eh measured is in the A horizon and the lowest in the C horizon. Similarly, biotites from the A horizons are the most oxidized compared with those from the lower horizons. In most of the samples the oxidation is accompanied by loss of K+ from the lattice, as demonstrated by a moderate degree of vermiculitization.

scholarly journals The role of soil redox conditions in microbial phosphorus cycling in humid tropical forests

Ecology ◽  
2019 ◽  
Vol 101 (2) ◽  
Author(s):  
Avner Gross ◽  
Yang Lin ◽  
Peter K. Weber ◽  
Jennifer Pett‐Ridge ◽  
Whendee L. Silver
Keyword(s):  
Tropical Forests ◽  
Redox Conditions ◽  
Phosphorus Cycling ◽  
Soil Redox

Mobilization, release and speciation of arsenic in an As-contaminated gold mine spoil under varied soil redox conditions

2020 ◽  
Author(s):  
Albert Kobina Mensah ◽  
Bernd Marschner ◽  
Jianxu Wang ◽  
Sabry M. Shaheen ◽  
Jörg Rinklebe
Keyword(s):  
Extraction Procedure ◽  
Mineralogical Composition ◽  
Redox Conditions ◽  
Mine Spoil ◽  
Residual Fraction ◽  
Reductive Dissolution ◽  
Gold Mine ◽  
Soil Redox ◽  
Reducing Conditions ◽  
The Impact

<p>Redox-induced release dynamics of arsenic (As) in an abandoned geogenic arsenic-contaminated gold mine spoil in Ghana has never been studied. Therefore, our aim was to investigate the effects of varied soil redox conditions on mobilisation and speciation of As from an abandoned highly contaminated gold mine spoil (with 4,283 mg As/kg soil) using an automated biogeochemical microcosm set-up. We also studied the impact of redox potential (E<sub>H</sub>)-dependent changes of pH, Fe, Mn, Al, S, Cl<sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, DOC, DIC, DC, DN and SUVA on the release dynamics of As. As mineralogical composition and speciation were further determined using a synchrotron-based X-ray absorption spectroscopy (XANES). Linear combination fits of XANES results indicated that scorodite (FeAsSO<sub>4</sub>) and arsenopyrite (FeAsS) are the two major As-containing minerals in the studied mine spoil. Geochemical fractionation using sequential extraction procedure indicated greater proportions of the extracted As in the amorphous iron oxide fraction III (1390.13 mg kg<sup>-1</sup>, 32.5% of the total As) and residual fraction V (2591.67 mg kg<sup>-1</sup>, 60.5% of the total As). Concentrations of dissolved Fe and SUVA were higher during reducing conditions and decreased under oxidising conditions and both showed negative significant relationships with E<sub>H</sub> (E<sub>H </sub>and SUVA: r = -0.76, <em>P <</em> 0.01; E<sub>H</sub> and Fe: r = -0.75). Mobilisation of As was greater under reducing conditions (dissolved As = 136.68 mg/L) than in oxidising environments (dissolved As = 8.06 mg/L). The release of As under low E<sub>H</sub> can be explained by the associated reductive dissolution of Fe oxides, as demonstrated by the high positive significant relationship between Fe and As (r = +0.97, <em>P <</em> 0.01). Dissolved As release dynamics can also be linked to desorption of aromatic carbon compounds on the surfaces of dissolved organic carbon, as demonstrated by the high positive significant correlation between SUVA and As (r = +0.573, <em>P <</em> 0.01). Further, the release dynamics of dissolved As was also affected by changes in pH (r = -0.4, <em>P <</em> 0.05), but were not affected by redox-induced dynamics of Mn, Al, S, Cl<sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, DOC, DIC, DC, DN. We conclude that conditions such as flooding and high rainfall in this contaminated mine spoil could create reducing conditions, leading to reductive dissolution of the arsenopyrite As-bearing primary mineral and may lead to higher As release into the groundwater, translocation into the food chain with potential impacts on human health.</p><p><strong>Keywords</strong>: Arsenopyrite, redox chemistry, arsenic mobilisation, gold mine spoil, reductive and oxidative dissolution.</p>

The influence of soil redox conditions on atrazine degradation in wetlands

1997 ◽  
Vol 66 (1) ◽  
pp. 41-46 ◽  
Author(s):  
R DeLaune
Keyword(s):  
Redox Conditions ◽  
Soil Redox ◽  
Atrazine Degradation

Root cortex structure and metabolic responses of Spartina patens to soil redox conditions

1991 ◽  
Vol 31 (1) ◽  
pp. 91-97 ◽  
Author(s):  
S.R. Pezeshki ◽  
S.W. Matthews ◽  
R.D. Delaune
Keyword(s):  
Spartina Patens ◽  
Redox Conditions ◽  
Metabolic Responses ◽  
Root Cortex ◽  
Soil Redox

scholarly journals Dynamic hydrology and plant-mediated effects reduce greenhouse gas emissions and alter wetland microbial communities

2020 ◽  
Author(s):  
Regina B. Bledsoe ◽  
Ariane L. Peralta
Keyword(s):  
Microbial Community ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Redox Status ◽  
Gas Production ◽  
Redox Conditions ◽  
Gas Emissions ◽  
Soil Redox ◽  
Microbial Function ◽  
Mediated Effects

AbstractWhile wetlands represent a small fraction (~7%) of the world’s land surface, it is estimated that one third of wetlands have been lost due to human activities. Wetland habitat loss decreases ecosystem functions such as improving water quality and mitigating climate change. These microbially mediated functions are dependent on particular soil redox conditions, which are altered by soil hydrology and the presence of plants. Differences in microbial physiology allow certain taxa (aerobes and facultative anaerobes) to adapt to fluctuating (dry/wet) hydrologic conditions, while other taxa (obligate anaerobes) are better adapted to continually saturated conditions. Therefore, the duration of hydrologic periods can affect soil microbial community structure and function. Further, plant-derived carbon, nutrients, and air are released by diffusion belowground which also impacts microbial activity in soils. In this study, we hypothesized that redox status due to continuous flooding would support greater abundance of microbial taxa involved in methanogenesis (obligate anaerobes), but plant-mediated oxygen transport would decrease methane emissions. Using a mesocosm design, we manipulated duration of hydrologic condition (i.e., stable dry, stable flooding, and alternating wet/dry) and presence of plants to induce soil redox changes in wetland soils. We measured soil redox status, used targeted amplicon sequencing to characterize the bacterial and archaeal communities, and measured greenhouse gas production to assess microbial function. Hydrology and to a lesser degree plant presence influenced soil redox conditions. Hydrologic history strongly influenced microbial community composition, but plant presence and hydrologic treatment altered microbial function to a great degree. As predicted, plant presence decreased greenhouse gas production in the wetland mesocosms. While previous studies do not often include plants when assessing greenhouse gas emissions, this study highlights that plant-mediated decreases in greenhouse gas emissions are significant. If plant-mediated effects are not considered when estimating the carbon balance of ecosystems, then wetland carbon storage could be underestimated.

scholarly journals Differential effects of redox conditions on the decomposition of litter and soil organic matter

2020 ◽  
Author(s):  
Yang Lin ◽  
Ashley N. Campbell ◽  
Amrita Bhattacharyya ◽  
Nicole DiDonato ◽  
Allison M. Thompson ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
High Resolution Mass Spectrometry ◽  
Terrestrial Ecosystems ◽  
Plant Litter ◽  
Redox Conditions ◽  
Co2 Production ◽  
Luquillo Experimental Forest ◽  
Soil Redox ◽  
Extractable Organic Matter

Abstract. Soil redox conditions exert substantial influence on biogeochemical processes in terrestrial ecosystems. Humid tropical forest soils are often characterized by fluctuating redox dynamics, yet how these dynamics affect patterns in soil versus litter decomposition and associated CO2 fluxes is not well understood. We used a 13C-labeled litter addition to explicitly follow the decomposition of litter-derived vs. native soil-derived organic matter in response to four different soil redox regimes – static oxic or anoxic, and two oscillating treatments – in soil from the Luquillo Experimental Forest, Puerto Rico. We coupled this incubation experiment with high-resolution mass spectrometry to characterize the preferential decomposition of specific classes of organic molecules. CO2 production from litter and soil organic matter (SOM) showed distinctly different responses to redox manipulation. The cumulative production of SOM-derived CO2 was positively correlated with the length of soil exposure to an oxic headspace (r = 0.89, n = 20), whereas cumulative 13C-litter-derived CO2 production was not linked to oxygen availability. The CO2 production rate from litter was highest under static anoxic conditions in the first half of the incubation period, and later dropped to the lowest among all redox treatments. In the consistently anoxic soils, we observed the depletion of more oxidized water-extractable organic matter (especially amino sugars, carbohydrates, and proteins) over time, suggesting that under anaerobic conditions, microbes preferentially used more oxidized litter-derived compounds during the early stages of decomposition. Results from kinetic modeling showed that more frequent anoxic exposure limited the decomposition of a slow-cycling C pool, but not a fast-cycling pool. Overall, our results demonstrate that substrate source – freshly added litter vs. native organic matter – plays an important role in the redox sensitivity of organic matter decomposition. In soil environments that regularly experience redox fluctuations, anaerobic heterotrophs can be surprisingly effective in degrading fresh plant litter.

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