scholarly journals Influence of Ecological Restoration on Mercury Mobility and Microbial Activities on Former Guyanese Mining Sites

2021 ◽  
Vol 11 (5) ◽  
pp. 2231
Author(s):  
Ewan Couic ◽  
Vanessa Alphonse ◽  
Alexandre Livet ◽  
Stéphanie Giusti-Miller ◽  
Noureddine Bousserrhine
Keyword(s):  
Soil Quality ◽  
Ecological Restoration ◽  
Microbial Activities ◽  
Potential Toxicity ◽  
Mining Sites ◽  
Soil Microbial ◽  
Rehabilitation Protocols ◽  
French Guyana ◽  
The Impact ◽  
Positive Effect

As rehabilitation efforts in Guyana are recent, there is little information on the effect of different ecological rehabilitation protocols for Guyana’s mining sites on biogeochemical cycles and mercury mobility. This study was conducted to assess the impact of different ecological restoration protocols on soil quality with the use of soil microbial indicators and by estimating the mercury mobility. We sampled soil from six rehabilitated mining sites in French Guyana with different ecological restoration procedures. We carried out measurements of enzymatic activities and an analysis of mercury environmental speciation to assess its potential toxicity according to a mobility gradient. The results obtained in this study show that the rehabilitation of mining sites has been carried out in a heterogeneous manner and soil quality is very variable, even in nearby sites. Sites that have been rehabilitated with fabaceous species have positive soil quality indicators. In addition, the results highlight a change in mercury mobility that is 82.1% correlated after co-inertia analysis with soil texture properties, which also confirms a direct effect of rehabilitation on mercury mobility. The non-restored sites had a much higher potential of mercury mobility and toxicity than the sites where ecological restoration was successful. These results highlight the positive effect of controlled rehabilitation and ecological restoration on microbiological activities and the potential toxicity of mercury.

scholarly journals Comparative assessment of microbial enzyme activity with compost and sewage sludge amendment

2015 ◽  
Vol 7 (2) ◽  
pp. 1021-1028
Author(s):  
Jatinder Kaur ◽  
Sandeep Sharma ◽  
Hargopal Singh
Keyword(s):  
Enzyme Activity ◽  
Sewage Sludge ◽  
Organic Carbon ◽  
Soil Microbial Activity ◽  
Available Phosphorus ◽  
Microbial Activities ◽  
Soil Microbial ◽  
Microbial Enzyme ◽  
Positive Effect ◽  
Digested Sewage Sludge

Changes in soil microbial activities were investigated to examine the effect of aerobically digested sewage sludge (SS) and compared with compost under incubation conditions over 63 days. Sandy soil was amended with 0.25, 0.5, 1.0 and 1.5 % w/w of compost and sewage sludge. Enzyme activity (dehydrogenase, alkaline phosphatase, acid phosphatase, phytase and urease) were examined at an interval of 3, 7, 14, 21, 28, 42 and 63 days. At the end of the experiment the change in organic carbon, nitrogen, potassium and phosphorus was also recorded.Results indicated that enzyme activities were substantially enhanced in presence of both amendments for first few days and the higher increases were measured at 1.5% of compost and sewage sludge amendment. Then an overall decrease in enzyme activity was recorded. Both the amendments also significantly increased the organic carbon, nitrogen and potassium of the soil while increase in available phosphorus was only recorded in treatment receiving compost. The present experiment indicated that addition of compost and sewage sludge have positive effect on soil microbial activity and can be safely used as soil amendment without having any adverse effect. Though, a previous examination of sewage sludge to be used must be made for heavy metals and pathogens.

scholarly journals Soil carbon and nitrogen fraction dynamics affected by tillage erosion

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiao-Jun Nie ◽  
He-Bing Zhang ◽  
Yan-Yan Su
Keyword(s):  
Organic Carbon ◽  
Soil Conservation ◽  
Microbial Activities ◽  
Soil C ◽  
Soil Microbial ◽  
Ammonium N ◽  
Soil C And N ◽  
Hydrolysable N ◽  
The Impact ◽  
Tillage Erosion

Abstract Understanding the impact of tillage erosion on soil organic carbon (SOC) and nitrogen (N) fractions is essential for targeted soil conservation in mountainous and hilly areas. However, little is known about this issue. In this study, we selected a tillage erosion-dominated hillslope from the Sichuan Basin, China, to determine the effect of tillage erosion on particulate OC (POC), dissolved OC (DOC), light fraction OC (LFOC), ammonium N (NH4+-N), nitrate N (NO3−-N) and alkali-hydrolysable N (AN). Additionally, we investigated the microbial activities in relation to soil C and N dynamics, including soil microbial biomass, β-glucosidase and urease activities. Tillage erosion induced serious soil loss in upper slope positions and soil deposition in lower slope positions. The observations of the various labile OC fraction distributions across the hillslope suggest that tillage erosion exerts less impact on DOC and LFOC dynamics but a notable effect on POC. The distribution pattern in total organic carbon under tillage erosion mainly depends on POC redistribution. The POC redistribution is a major factor affecting microbial activities. The AN is more prone to the tillage erosion impact than NH4+-N and NO3−-N. Effective soil conservation measures should be taken to weaken the adverse impacts of tillage erosion on POC and AN redistribution in sloping farmlands.

scholarly journals Agricultural mulching and fungicides—impacts on fungal biomass, mycotoxin occurrence, and soil organic matter decomposition

2021 ◽  
Author(s):  
Maximilian Meyer ◽  
Dörte Diehl ◽  
Gabriele Ellen Schaumann ◽  
Katherine Muñoz
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Soil Quality ◽  
Fungal Biomass ◽  
Soil Depth ◽  
Soil Parameters ◽  
Fungicide Application ◽  
Soil Microbial ◽  
The Impact

AbstractPlastic and straw coverage (PC and SC) are often combined with fungicide application but their influence on fungicide entry into soil and the resulting consequences for soil quality are still unknown. The objective of this study was to investigate the impact of PC and SC, combined with fungicide application, on soil residual concentrations of fungicides (fenhexamid, cyprodinil, and fludioxonil), soil fungal biomass, mycotoxin occurrence, and soil organic matter (SOM) decomposition, depending on soil depth (0–10, 10–30, 30–60 cm) and time (1 month prior to fungicide application and respectively 1 week, 5 weeks, and 4 months afterwards). Soil analyses comprised fungicides, fusarium mycotoxins (deoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, and zearalenone), ergosterol, soil microbial carbon and nitrogen, soil organic carbon, dissolved organic carbon, and pH. Fludioxonil and cyprodinil concentrations were higher under SC than under PC 1 week and 5 weeks after fungicide application (up to three times in the topsoil) but no differences were observed anymore after 4 months. Fenhexamid was not detected, presumably because of its fast dissipation in soil. The higher fludioxonil and cyprodinil concentrations under SC strongly reduced the fungal biomass and shifted microbial community towards larger bacterial fraction in the topsoil and enhanced the abundance and concentration of deoxynivalenol and 15-acetyldeoxynivalenol 5 weeks after fungicide application. Independent from the different fungicide concentrations, the decomposition of SOM was temporarily reduced after fungicide application under both coverage types. However, although PC and SC caused different concentrations of fungicide residues in soil, their impact on the investigated soil parameters was minor and transient (< 4 months) and hence not critical for soil quality.

Microbial indicators for assessing the adverse impact of technical-grade hexachlorocyclohexane on soil quality

2015 ◽  
Vol 6 ◽  
Author(s):  
Mikel Anza
Keyword(s):  
Soil Quality ◽  
Microbial Biomass Carbon ◽  
Polluted Soil ◽  
Soil Quality Index ◽  
Metabolic Potential ◽  
Technical Grade ◽  
Microbial Properties ◽  
Soil Microbial ◽  
Soil Microbial Properties ◽  
The Impact

Technical-grade hexachlorocyclohexane (HCH) has been widely used for human health and agricultural purposes. Consequently, HCH residues have entered the soil ecosystem with concomitant deleterious effects on soil quality. The aim of this study was to assess the impact of HCH on soil microbial properties as biological indicators of soil quality. To this end, non-polluted soil was spiked with different amounts of a heavily HCH-polluted soil in order to obtain a concentration gradient between 0 and 1,500 mg HCH kg<sup>-1</sup> dry matter soil. The mixtures were incubated under laboratory conditions for 2 months. Dehydrogenase activity, fluorescein diacetate hydrolysis activity (FDA), basal respiration, substrate-induced respiration (SIR), microbial biomass carbon, metabolic potential, and the soil quality index were negatively affected by increasing HCH concentrations in soil, in many cases following an exponential pattern. FDA and SIR appear <em>a priori</em> suitable indicators for the impact of HCH on soil microbial properties and, hence, soil quality.

scholarly journals Utilization of sewage sludge as an ameliorant for reclamation of technogenically disturbed lands

2021 ◽  
Vol 251 ◽  
pp. 767-776
Author(s):  
Tatyana Petrova ◽  
Edelina Rudzisha
Keyword(s):  
Sewage Sludge ◽  
Plant Communities ◽  
Land Reclamation ◽  
Chemical Parameters ◽  
Mining Sites ◽  
Physical And Chemical ◽  
The Impact ◽  
Positive Effect ◽  
Vegetation Layer ◽  
Growth Indicators

When rehabilitating technogenically disturbed lands of mining facilities, fertilizers and ameliorants are to be applied due to the lack of organic matter and nutrients required for the restoration of the soil and vegetation layer. The use of unconventional fertilizers (ameliorants) based on sewage sludge is one of the actual directions of land reclamation at mining sites. The purpose of the work is to summarize and analyze up-to-date information on the effectiveness of the use of sewage sludge for the reclamation of technogenically disturbed lands of mining and processing industries. The analysis is based on a review of recent studies aimed at assessing the impact of introduced sediment on soils, plant communities, and rehabilitated areas. The introduction of sewage sludge has a positive effect on the physical and chemical parameters of the soil (optimizes density and aggregation), saturates it with nutrients, i.e. N, P, K, Ca, Mg, and Na, thus improving plant growth indicators. However, it may contain a number of heavy metals and pathogens; therefore, studies of each sediment and conditions of reclaimed areas are necessary.

scholarly journals The Impact of Ecological Restoration on Biogeochemical Cycling and Mercury Mobilization in Anoxic Conditions on Former Mining Sites in French Guiana

2021 ◽  
Vol 9 (8) ◽  
pp. 1702
Author(s):  
Ewan Couic ◽  
Alicia Tribondeau ◽  
Vanessa Alphonse ◽  
Alexandre Livet ◽  
Michel Grimaldi ◽  
...  
Keyword(s):  
Ecological Restoration ◽  
French Guiana ◽  
Acacia Mangium ◽  
Anaerobic Conditions ◽  
Mining Sites ◽  
Iron Reducing Bacteria ◽  
Sulfate Reducing ◽  
Sulphide Production ◽  
Reducing Bacteria ◽  
The Impact

Successive years of gold mining in French Guiana has resulted in soil degradation and deforestation leading to the pollution and erosion of mining plots. Due to erosion and topography, gold panning sites are submitted to hydromorphy during rainfall and groundwater increases. This original study focused on characterizing the impact of hydromorphic anaerobic periods on bio-geochemical cycles. We sampled soil from five rehabilitated sites in French Guiana, including sites with herbaceous vegetation and sites restored with fabaceous plants, Clitoria racemosa (Cli) mon-oculture, Acacia mangium (Aca) monoculture, Clitoria racemosa and Acacia mangium (Mix) bi-culture. We conducted mesocosm experiments where soil samples were incubated in anaerobic conditions for 35 days. To evaluate the effect of anaerobic conditions on biogeochemical cycles, we measured the following parameters related to iron-reducing bacteria and sulfate-reducing bacteria metabolism throughout the experiment: CO2 release, carbon dissolution, sulphide production and sulphate mobilization. We also monitored the solubilization of iron oxyhydroxides, manganese oxides, aluminum oxides and mercury in the culture medium. Iron-reducing bacteria (IRB) and sulfate-reducing bacteria (SRB) are described as the major players in the dynamics of iron, sulfur and metal elements including mercury in tropical environments. The results revealed two trends in these rehabilitated sites. In the Aca and Mix sites, bacterial iron-reducing activity coupled with manganese solubilization was detected with no mercury solubilization. In herbaceous sites, a low anaerobic activity coupled with sulphide production and mercury solubilization were detected. These results are the first that report the presence and activity of iron- and sulfate-reductive communities at rehabilitated mining sites and their interactions with the dynamics of metallic elements and mercury. These results report, however, the positive impact of ecological restoration of mining sites in French Guiana by reducing IRB and SRB activities, the potential mobility of mercury and its risk of transfer and methylation.

Mercury behaviour and C, N, and P biogeochemical cycles during ecological restoration processes of old mining sites in French Guiana

2018 ◽  
Vol 20 (4) ◽  
pp. 657-672
Author(s):  
Ewan Couic ◽  
Michel Grimaldi ◽  
Vanessa Alphonse ◽  
Clarisse Balland-Bolou-Bi ◽  
Alexandre Livet ◽  
...  
Keyword(s):  
Ecological Restoration ◽  
French Guiana ◽  
Biogeochemical Cycles ◽  
Microbial Activities ◽  
Mining Sites

Restoration processes affect positively microbial activities and decrease mercury mobility.

scholarly journals Vegetation Degradation of Guanshan Grassland Suppresses the Microbial Biomass and Activity of Soil

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 203
Author(s):  
Yanmei Liu ◽  
Hangyu Yang ◽  
Zisheng Xing ◽  
Yali Zou ◽  
Zheming Cui
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Enzymatic Activities ◽  
Microbial Activities ◽  
Total N ◽  
Microbial Properties ◽  
Vegetation Degradation ◽  
Soil Microbial ◽  
Soil Microbial Properties ◽  
The Impact

Changes in vegetation influence the function of grassland ecosystems. A degradation of the vegetation type has been found from high to low altitudes in Guanshan grassland in the order of forest grassland (FG) < shrub grassland (SG) < herb grassland (HG). However, there is poor information regarding the effect of vegetation degradation on soil microbes in Guanshan grassland. Therefore, our study evaluated the impact of vegetation degradation on the microbial parameters of soil, as well as the mechanisms responsible for these variations. Soils were sampled from 0 to 30 cm under the FG, SG, and HG in Guanshan grassland for determining the microbial biomass, enzymatic activities, basal respiration (BR), and metabolic quotient (qCO2) in April and July 2017. The results showed that vegetation types are important factors that obviously influence the above-mentioned soil microbial properties. The FG and SG had significantly higher soil microbial biomass, enzymatic activities, and BR than those of the HG, but markedly lower qCO2 (p < 0.05). Soil pH, available nitrogen (AN), organic carbon (SOC), total phosphorus (TP), available P (AP), and total N (TN) were key factors in the decline in the soil microbial biomass and microbial activities of the degraded vegetation. Moreover, slope aspects also affected the soil microbial properties, with the east slope having higher soil microbial biomass, enzymatic activities, and BR and lower qCO2 than the west slope. Conclusively, vegetation degradation has led to a decline in the soil microbial biomass and microbial activities, indicating the degradation of the Guanshan grassland ecosystem.

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