High Organic Carbon Content Research Articles

Kinetic effects of anaerobic staging and aeration rates on sequencing batch moving bed biofilm reactors: Carbon, nitrogen, and phosphorus treatment of cheese production wastewater

The food and beverage industry produces wastewaters containing high concentrations of organic carbon and nutrients, which when discharged leads to eutrophication and algal blooms. Given recent stringencies in effluent regulations, industries are required to treat their wastewater on-site. There is a critical need for compact, high-rate, cost-effective wastewater technologies to treat industrial wastewaters, such as the sequencing batch moving bed biofilm reactor. The aim of this study is to investigate the potential and evaluate the performance of the sequencing batch moving bed biofilm reactor cycling between anaerobic and aerobic stages to treat high-strength food and beverage wastewaters. Specifically, this study focuses on the effects of anaerobic staging times and enhanced aeration on the removal of carbon, nitrogen, and phosphorous from cheese production wastewaters. Increasing anaerobic staging times was found to improve the removal rates of carbon beyond previously reported moving bed biofilm reactor results. Increasing the anaerobic stage however decreased the total nitrogen removal, with organic nitrogen undergoing ammonification during the anaerobic stage. This study demonstrates an optimum anaerobic staging time of 138 min; with a carbon removal rate of 31.1 g-sCOD·m−2d−1 and a nitrogen removal rate of 1.3 g-N·m−2d−1. Enhanced aeration was found to be detrimental to phosphorous removal, where a moderate aeration rate demonstrated a net total phosphorous removal of approximately 22 mg-P·l−1 with the phosphorous-content of the suspended solids being approximately 4%. Finally, the sequencing batch moving bed biofilm reactor shows potential for on-site treatment of carbon, nitrogen, and phosphorous from cheese production wastewater.

Influence of mussel shell, oak ash and pine bark on the adsorption and desorption of sulfonamides in agricultural soils

Taking into account the high mobility and environmental risks due to sulfonamide antibiotics as emerging pollutants, batch-type experiments were performed to study adsorption/desorption of three sulfonamides (sulfadiazine -SDZ-, sulfamethazine -SMT- and sulfachloropyridazine -SCP-) in three agricultural soils. The study was carried out both for un-amended and amended soil samples, using different doses (0, 12, 24 and 48 Mg ha−1) of three different by-products (mussel shell, oak ash and pine bark). Adsorption on un-amended soils was rather low, with percentages between 11 and 45% for SDZ, 20–64% for SMT, and 19–65% for SCP. Both the Linear and Freundlich models fitted well to adsorption curves. In the case of un-amended soils, and regarding the Linear model, the values of the coefficient of distribution (Kd, expressed in L kg−1) were between 0.6 and 1.3 for SDZ, between 0.7 and 1.1 for SMT, and between 0.6 and 2.6 for SCP. As regards the Freundlich model, the values of the adsorption constant (KF, expressed in L1/n μmol1−1/n kg−1), were in the range 0.4–1.9 for SDZ, 0.9–2.9 for SMT, and 1.2–3.8 for SCP. Simultaneously, desorption percentages were high, reaching 13.7–47.7% for SDZ, 12.6–35.1% for SMT, and 13.7–34.3% for SCP, when the highest initial antibiotic concentration (50 μmol L−1) was added, thus indicating low retention and high mobility for these compounds in soils. Mussel shell and oak ash amendments did not increase retention of any of the three sulfonamides. However, the incorporation of pine bark resulted in an increase in the adsorption and decrease in desorption for all three antibiotics. Specifically, for soils amended with pine bark at 48 Mg ha−1, Kd values (expressed in L kg−1) were between 2.1 and 2.9 for SDZ, between 3.4 and 3.6 for SMT, and between 2.5 and 8.2 for SCP. Regarding KF (expressed in L1/n μmol1−1/n kg−1), its values ranged from 5.6 to 6.3 for SDZ, 6.2–8.8 for SMT, and 5.3–7.1 for SCP. These scores were clearly higher than those of un-amended soils, and pine bark amendment also resulted in lower desorption percentages, ranging 8.7–11.4% for SDZ, 4.0–10.7% for SMT, and 6.5–16.9% for SCP. This positive effect on the retention of sulfonamides due to pine bark can be attributed to its high organic carbon content (48.6%), as well as to its acidic pHw (4.0). Therefore, pine bark amendment can be considered an effective alternative to increase the retention of sulfonamides in soils, thus reducing their bioavailability and transport to other environmental compartments, and subsequent risks of negative impacts on human and environmental health.

Animal carcass- and wood-derived biochars improved nutrient bioavailability, enzyme activity, and plant growth in metal-phthalic acid ester co-contaminated soils: A trial for reclamation and improvement of degraded soils

Reclamation of degraded soils such as those with low organic carbon content and soils co-contaminated with toxic elements and phthalic acid esters (PAEs) is of great concern. Little is known about the efficiency of plant- and animal-derived biochars for improving plant growth and physicochemical and biological properties of co-contaminated soils, particularly under low content of organic matter. Hence, a pot trial was carried out by growing pak choi (Brassica chinensis L.) to assess the influence of different doses (0, 0.5, 1, 2, and 4%) of animal (pig carcass) and wood (Platanus orientalis) derived biochars on soil properties, nutrient availabilities, plant growth, and soil enzyme activities in two soils containing low (LOC) and high (HOC) organic carbon contents and co-contaminated with di-(2-ethylhexyl) phthalic acid (DEHP) and cadmium (Cd). Biochar applications improved pH, salinity, carbon content, and cation exchange capacity of both soils. Addition of biochars significantly increased the bioavailability and uptake of phosphorus and potassium in the plants in both soils with greater effects from pig biochar than wood biochar. Biochar additions also significantly enhanced urease, sucrase, and catalase activities, but suppressed acid phosphatase activity in both soils. The impact of pig biochar was stronger on urease and acid phosphatase, while the wood biochar was more effective with sucrase and catalase activities. The biomass yield of pak choi was significantly increased after biochar addition to both soils, especially in 2% pig biochar treatment in the LOC soil. The positive response of soil enzymes activities and plant growth for biochar addition to the Cd and DEHP co-contaminated soils indicate that both biochars, particularly the pig biochar can mitigate the risk of these pollutants and prove to be eco-friendly and low-cost amendments for reclaiming these degraded soils.

Temporal Variations and Characteristics of the Carbonaceous Species in PM2.5 Measured at Anmyeon Island, a Background Site in Korea

Routine measurements of carbonaceous species in PM2.5 inculidng organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and humic-like-substance carbon (HULIS-C) in PM2.5 were performed at Anmyeon Island (AI) to clarify the seasonal variation and carbonaceous aerosol concentrations at a background site in Korea between 2015 and 2016. The annual average OC and EC concentrations were 4.52±3.25 μg/m3 and 0.46±0.28 μg/m3, respectively, and there were no clear seasonal variations in OC and EC concentrations. The average concentrations of WSOC and water-insoluble organic carbon (WISOC) were 2.56±1.95 μg/m3 and 1.96±1.45 μg/m3, respectively, and their composition in OC showed high temporal variations. A low correlation between WISOC and EC was observed, while WSOC concentrations were highly correlated with secondary organic carbon concentrations, which were estimated using the EC tracer method. The results indicate that the formation of secondary organic aerosols is a major factor for the determination of WSOC concentrations in this region. HULIS-C was the major component of WSOC, accounting for 39–99% of WSOC and the average concentration was 1.88±1.52 μg/m3. Two distinct periods with high carbonaceous speciess in PM2.5 were observed and characterized by their OC/EC ratios. The high concentration of OC with high ratio of OC/EC was due to the influence of a mixture of emissions from biomass burning and secondary formation transported from outside AI. While, the high concentrations of OC and EC with low OC/EC ratio were related to local vehicular emissions.

Long term effect of chemical fertilizers and amendments on chemical pools of nitrogen in maize-wheat cropping system in an acid Alfisol

The present investigation was carried out in the ongoing long term fertilizer experiment at Department of soil science, CSKHPKV Palampur. The influence of thirty six years of cropping with different chemical fertilizers and amendments on the contents and total N, inorganic N and organic N fractions at 0-0.15 m and 0.15-0.30 m depths was investigated in an Acid Alfisol. Continuous combined use of chemical fertilizers and FYM and manual weeding in 100% NPK treated plots resulted in significant increase in the soil organic carbon content compared to rest of the treatments. However, higher organic carbon content was recorded under surface soils. Continuous application of chemical fertilizers either alone or in combination with FYM or lime influenced different organic and inorganic nitrogen fractions significantly except non hydrolysable-N at both the depths. Hydrolysable ammonical-N was found to be the most dominant organic nitrogen fraction. Different organic and inorganic –N fractions at surface and subsurface soils were significantly and positively correlated with available N.

A rapid hydroclimate change and its influence on the Songliao Basin during the Santonian-Campanian transition as recorded by compound-specific isotopes

Reconstruction of the paleoclimate and paleoenvironment of the Songliao Basin has important theoretical and practical significance to reveal the regional continental climate characteristics and continental organic matter accumulation under the Cretaceous greenhouse climate conditions. Here, we report the composition of biomarkers and the stable carbon and hydrogen isotope compositions of n-alkanes from Nenjiang Formation sediments in the Songliao Basin, which provide information on the source of organisms, paleoenvironmental conditions, and paleoclimate changes during the Late Cretaceous. Our hydrogen isotope records of n-alkanes displayed a significantly negative shift, indicating that a dramatically wet climate occurred during the Santonian-Campanian transition. A wet climate, such as that during a prolonged rainfall event, had a significant impact on the lake and resulted in the lake level increasing and the salinity decreasing in the surface water during this period. However, the freshwater input increased the salinity difference between the upper and lower water layers, which caused stable water stratification to occur in the lake. In addition, the high total organic carbon (TOC) content indicates high primary productivity because of increased precipitation carrying more terrigenous nutrients into the lake, which resulted in eutrophication during this period. Notably, the increased aryl isoprenoid ratios and the occurrence of isorenieratane indicates that photic zone euxinia (PZE) was enhanced during the Santonian-Campanian transition, which was possibly due to the dramatic change in the hydroclimate. We speculate that the large freshwater input promoted the formation of PZE in the lake. Then, PZE restricted the habitat available for aerobic organisms, which had fatal effects on the lake ecosystem.

Effect of FeS on mercury behavior in mercury-contaminated stream sediment: A case study of Pohang Gumu Creek in South Korea

This study investigated mercury contamination with respect to the sediment characteristics in Gumu Creek near the Pohang Industrial Complex, South Korea. The contaminated sediment had high levels of Hg, exceeding 250 mg Hg/kg sediment at the sampling position, and high concentrations of iron, sulfur, and organic carbon under extreme anaerobic conditions. The anoxic condition of the sediment produced large amounts of FeS. Hg L3-edge EXAFS analysis revealed that FeS controlled the Hg species in the sediment mainly as β-HgS like precipitation or Hg-S complexation. We also speculated that the presence of FeS induced the abiotic reduction of Hg(II) to Hg(0) and consequently suppressed the formation of highly toxic methylated mercury species. The results obtained in this study are mostly consistent with those reported in previous studies of geochemical reactions of FeS in controlling Hg(II) under pure FeS mineral systems under laboratory scenarios. This study demonstrates that the laboratory controlled reaction scenarios can explain the field behavior of Hg in the contaminated anoxic sediment of the Gumu Creek site.

The 3R Principles for Applying Biochar to Improve Soil Health

Amending soil with biochar is a promising approach to persistently improve soil health and promote crop growth. The efficacy of soil biochar amendment, however, is soil specific, biochar dependent, and influenced by the biochar application programs. To maximize the benefits of biochar application, this paper proposes the 3R principles for applying biochar to soils: right biochar source, right application rate, and right placement in soil. The quality of biochar as a soil amendment varies significantly with the feedstock and the production conditions. Biochar products capable of everlastingly sustaining soil health are those with high stable organic carbon (OC) content and high water- and nutrient-holding capacities that are manufactured from uncontaminated biomass materials. Acidic, coarse-textured, highly leached soils respond remarkably more to biochar amendment than other types of soils. Soil amendment with particular biochars at as low as 0.1 mass% (equivalent to 2 Mg ha−1) may enhance the seasonal crop productivity. To achieve the evident, long-term soil health improvement effects, wood- and crop residue-derived biochars should be applied to soil at one time or cumulatively 2–5 mass% and manure-derived biochars at 1–3 mass% soil. Optimal amendment rates of particular biochar soil systems should be prescreened to ensure the pH of newly treated soils is less than 7.5 and the electrical conductivity (EC) below 2.7 dS m−1 (in 1:1 soil/water slurry). To maximize the soil health benefits while minimizing the erosion risk, biochar amendment should be implemented through broadcasting granular biochar in moistened conditions or in compost mixtures to cropland under low-wind weather followed by thorough and uniform incorporation into the 0–15 cm soil layer. Biochars are generally low in plant macronutrients and cannot serve as a major nutrient source (especially N) to plants. Combined chemical fertilization is necessary to realize the synergic beneficial effects of biochar amendment.

Hydrocarbon generation and storage mechanisms of deep-water shelf shales of Ordovician Wufeng Formation–Silurian Longmaxi Formation in Sichuan Basin, China

As the hydrocarbon generation and storage mechanisms of high quality shales of Upper Ordovician Wufeng Formation- Lower Silurian Longmaxi Formation remain unclear, based on geological conditions and experimental modelling of shale gas formation, the shale gas generation and accumulation mechanisms as well as their coupling relationships of deep-water shelf shales in Wufeng–Longmaxi Formation of Sichuan Basin were analyzed from petrology, mineralogy, and geochemistry. The high quality shales of Wufeng–Longmaxi Formation in Sichuan Basin are characterized by high thermal evolution, high hydrocarbon generation intensity, good material base, and good roof and floor conditions; the high quality deep-water shelf shale not only has high biogenic silicon content and organic carbon content, but also high porosity coupling. It is concluded that: (1) The shales had good preservation conditions and high retainment of crude oil in the early times, and the shale gas was mainly from cracking of crude oil. (2) The biogenic silicon (opal A) turned into crystal quartz in early times of burial diagenesis, lots of micro-size intergranular pores were produced in the same time; moreover, the biogenic silicon frame had high resistance to compaction, thus it provided the conditions not only for oil charge in the early stage, but also for formation and preservation of nanometer cellular-like pores, and was the key factor enabling the preservation of organic pores. (3) The high quality shale of Wufeng–Longmaxi Formation had high brittleness, strong homogeneity, siliceous intergranular micro-pores and nanometer organic pores, which were conducive to the formation of complicated fissure network connecting the siliceous intergranular nano-pores, and thus high and stable production of shale gas.

STRATIGRAPHIC FRAMEWORK AND PETROLEUM GEOCHEMISTRY OLIGOCENE SOURCE ROCKS, NORTHERN SONG HONG BASIN

The lacustrine oil-prone organic-rich mudstones in the Oligocene are the most important source rocks which have contributed to generate significant hydrocarbon accumulations in the northern Song Hong basin but still poor understanding due to the limitation of data. Newly c. 800km2 3D seismic data and well data allows investigating the stratigraphy and geochemistry of the northern Song Hong basin in detail to define the stratigraphic framework and hydrocarbon potential. The area is characterized by three relatively elongate grabens which are separated by the northeast-southwest basement faults. The most completed synrift sequence is observed in the central graben and is divided into three distinct sections, lower section (Ol), middle (Om) and upper (Ou), corresponding to three phases defined by tectonic systems tracts, from rift initiation to rift development and finally fill up phase. Uplift at the end of Oligocene has strongly modified the syn-rift sequences, resulting in folding, reactivated some basement faults and generated a series of new EW trending faults which may act as potential structural traps in the area. Organic geochemical analysis of the lacustrine mudstone samples from Ol and Om section of well D-1X shows fair to high organic carbon contents, Total Organic Carbon (TOC) 0.51 - 4.86 wt% and Hydrogen Index (HI) 273 - 552 mg HC/g TOC, corresponding to the type II kerogen. Biomarkers indicate the contribution of algal, high land plant, and bacterial sources to the composition of organic matters. Organic matters were deposited in the less oxic environment, in the fresh-water to brackish marine influence.

Effects of pine bark amendment on the transport of sulfonamide antibiotics in soils

In the present work, laboratory column experiments were carried out to study the effect of pine bark amendment (at doses of 0, 12, 48 and 96 Mg ha−1) on the transport of three sulfonamide antibiotics (sulfadiazine –SDZ-, sulfamethazine –SMT-, and sulfachloropyridazine –SCP-) through two crop soils. All three sulfonamides showed high mobility in the unamend soils, with absence of retention in most cases. However, some differences were detected regarding the degree of interactions between sulfonamides and soils, being higher for soil 1, which was attributed to its higher organic carbon content. For both soils, interactions with the antibiotics studied followed the sequence SDZ < SMT < SCP, indicating an increase as a function of the hydrophobicity of sulfonamides. Pine bark amendment significantly increased the retention of the three sulfonamides in both soils. Specifically, in the case of soil 1, the incorporation of the highest dose of pine bark (96 Mg ha−1) caused that retention increased from 0% to 70.3% for SDZ, from 2.7% to 71.3% for SMT, and from 0% to 85.4% for SCP. This effect of pine bark is mainly attributed to its high organic carbon content (48.6%), including substances with potential to interact and retain antibiotics, as well as to its acidic pH (4.5). Therefore, pine bark amendment would be an effective alternative to reduce the transport of sulfonamides in soils and, thus, decrease risks of passing to other environmental compartments, as well as harmful effects on the environment and public health.

Expression of Early Cretaceous global anoxic events in Northeastern Brazilian basins

In different basins around the world, organic-rich layers from the Cretaceous are being associated with perturbations in the global carbon cycle that reflect abrupt climatic and oceanic changes responsible for increased anoxia. In the northeastern part of Brazil, organic-rich rocks from the Parnaíba and São Luís basins—deposited during the late Aptian-early Albian and associated with the Codó Formation—offer an interesting stratigraphic record to evaluate the influence of oceanic anoxic events on restricted marine paleoenvironments. Therefore, an integrated study using different geochemical proxies (total organic carbon (TOC), Rock-Eval pyrolysis, δ13Corg, δ15Ntotal, and biomarkers) was conducted on sedimentary sections of the São Luís and Parnaíba basins (Codó Formation), which are assigned to the upper Aptian-lower Albian. The δ13Corg data obtained were compared with the isotopic δ13Corg profile from the section of the Santa Rosa Canyon (Mexico) where the record of the anoxic Aptian-Albian event (oceanic anoxic event 1b) was characterized. The stratigraphic record of the Codó Formation in both the basins presented the C11–C12 Cretaceous isotopic segments with clear 13Corg depletion associated with a spike in TOC that reached 10% at Parnaíba Basin and 15% at São Luís Basin. At Parnaíba Basin, biomarker results showed a high abundance of the terpane gammacerane, suggesting conditions of water-mass stratification and hypersalinity, setting that took place in the southern hemisphere during OAE 1b and enhanced preservation of organic matter in different basins. Also, marine sources were evidenced by the predominance of the C27 ααα(R) sterane and by the identification of the C30 ααα(R) sterane. In addition, the presence of the biomarkers C27 trisnorhopane 17β, C29αβ and C29 ααα (R) sterane reflect the contribution of terrigenous material to organic matter, which is commonly observed during anoxic events due to the acceleration of the hydrological cycle. Nitrogen isotopes revealed a relatively positive value (greater than 3%) which suggests anaerobic reduction of NO3- to N2 under suboxic to anoxic conditions (denitrification). Otherwise, a negative δ15N trend was observed in samples from the negative δ13Corg trend which represented a high organic carbon content. This δ15N signature suggests a decrease in the available NO3- (beginning of exhaustion) and an enhanced level of nitrogen fixation by microbial organisms during the anoxic event, which is also supported by a higher abundance of prokaryotic biomarkers (hopanes) in the organic matter.

Method development for estimating soil organic carbon content in an alpine region using soil moisture data

The high soil organic carbon (SOC) content in alpine meadow can significantly change soil hydrothermal properties and further affect the soil temperature and moisture as well as the surface water and energy budget. Therefore, this study first introduces a parameterization scheme to describe the effect of SOC content on soil hydraulic and thermal parameters in a land surface model (LSM), and then the SOC content is estimated by minimizing the difference between observed and simulated surface-layer soil moisture. The accuracy of the estimated SOC content was evaluated using in situ observation data at a soil moisture and temperature-measuring network in Naqu, central Tibetan Plateau. Sensitivity experiments show that the optimum time window for stabilizing the estimation results cannot be shorter than three years. In the experimental area, the estimated SOC content can generally reflect the spatial distribution of the measurements, with a root mean square error of 0.099 m3 m−3, a mean bias of 0.043 m3 m−3, and a correlation coefficient of 0.695. The estimated SOC content is not sensitive to the temporal frequency of the soil moisture data input. Even if the temporal frequency is as low as that of current soil moisture products derived from passive microwave satellites, the estimation result is still stable. Therefore, by combining a high-quality satellite soil moisture product and a parameter optimization method, it is possible to obtain grid-scale effective parameter values, such as SOC content, for an LSM and improve the simulation ability of the LSM.

Effects of simulated sea level rise on stocks and sources of soil organic carbon in Kandelia obovata mangrove forests

Changes in stocks and sources of soil organic carbon (OC) with sea level rise (SLR) are crucial to carbon processes and sequestration benefits in mangrove forests. Soil OC contents and stocks were compared among three 11 years-old Kandelia obovata mangrove forests with SLR of 0, 40 and 80 cm, respectively, simulating the current, future ~100 years’ and future ~200 years’ SLR of mangrove forests along Jiulong River Estuary, an important K. obovata area in Fujian, China. Contribution rates of mangrove plants and allochthonous suspended particulate organic matter in tidal water (SPOM) to soil OC were also estimated. Significantly higher soil OC contents and stocks were measured at site SLR 80 cm. Mean OC stocks at sites SLR 80 cm, SLR 40 cm and SLR 0 cm were 23.82, 16.68 and 17.85 kg C m−2, respectively. High soil labile organic carbon (LOC) contents were also found at site SLR 80 cm, while low profiles of soil δ13C values were measured at site SLR 40 cm. Mean contribution rates of mangrove plants to soil OC were 36.65%, 35.42% and 21.79% at sites SLR 80 cm, SLR 40 cm and SLR 0 cm, respectively, and significantly higher OC contribution rates of mangrove plants were found at site SLR 80 cm. These indicated that SLR will increase soil OC stock and mangrove contribution to soil OC.

Evaluation of Non-Conventional Biological and Molecular Parameters as Potential Indicators of Quality and Functionality of Urban Biosolids Used as Organic Amendments of Agricultural Soils

Biosolids are waste from wastewater treatment and have a high content of organic matter and nutrients. In this study, not conventional physicochemical and biological properties of biosolids produced during different seasons of the year were evaluated. These properties are not considered in environmental regulations; however, they are of agronomic interest as indicators of quality and functionality in soils. Also, molecular analysis by Fourier-transform infrared (FTIR) was conducted, enzymatic analysis using the APIZYM® system was performed and two indices of functional and microbial diversity were established. The results showed that the biosolids had a high content of total organic carbon, total nitrogen, P, and K. FTIR analyses showed that chemical composition of biosolids was similar during all year. The C and N of microbial biomass demonstrated presence of active microorganisms, as well as a uniformity in its richness and abundance of species that could present a positive synergy with soil microorganisms. The enzymatic activities showed that the biosolids contained an enzymatic machinery available to promote the mineralisation of the organic matter of biosolids and could even transcend into the soil. Finally, biological properties can be used as indicators of quality and functionality of biosolids before being used as an organic amendment, especially in agricultural soils.

Resilience and microstructural resistance of Archaeological Dark Earths with different soil organic carbon contents in Western Amazonia, Brazil

Archaeological Dark Earths (ADE) are anthropogenic soils with high fertility and excellent physical conditions due to high soil organic carbon (SOC) content. However, climate change, land use and soil management can increase SOC mineralization, resulting in microstructure damage of these soils. To verify the effect of SOC loss, we collected deformed samples from the surface horizon and simulated the reduction of C with the application of 0.2, 0.4 and 0.6 ml of hydrogen peroxide 35% per gram of soil, resulting in three treatments of different oxidation levels and untreated soil. Both original and oxidized soil were submitted to an amplitude sweep test with controlled strain and a thixotropy test, in a compact modular rheometer. To characterize the effect of soil properties on rheology and resilience of ADEs, we performed a correlation analysis with physico-chemical properties from untreated soil. Higher clay and organic matter contents increased the microstructure elasticity of ADEs. The increase in base saturation, mainly due to the high Ca+2 content, also favors elasticity. The soil’s resilience is a result of the joint effect of particle size distribution, base saturation and SOC content. The microstructure recovers fast, regardless of the disturbance intensity. The SOC loss affected the microstructure differently in each ADE. These differences are not dependent on the amount of SOC lost and mostly labile SOC (as removed by low oxidation intensity) was responsible for soil strength.

Source rock potential and depositional environment of the Lower Oligocene İhsaniye Formation in NW Turkey (Thrace, Karaburun)

The Lower Oligocene succession of the Ihsaniye Formation, exposed at Karaburun on the Turkish (Thrace) coast of the Black Sea, provides insights into potential hydrocarbon source rock extent in the southwestern part of the Black Sea Basin. Presently, no detailed study of the Ihsaniye Formation exists with regards to organic matter content and type. We analyzed 78 fine-grained samples from a c. 70-m-thick section near Karaburun. Relatively high total organic carbon (TOC) contents (average 1.45 wt.%) are present in the lower part of the Ihsaniye Formation; the hydrogen index values reach a maximum of 252 mg HC/g TOC, indicating the presence of type III-II kerogen, and the organic matter is thermally immature (Tmax 418 °C). The presence of foraminifera and TOC/S ratios below 2.8 confirm a fully marine environment. Elevated TOC contents and very low pristane/phytane ratios indicate an oxygen-depleted environment during deposition of the lower part of the Ihsaniye Formation. The quartz/clay minerals ratio suggests a deepening trend in the lower part of the succession and a shallowing trend in the upper part. Peculiarly, the low salinity Solenovian Event (in nannofossil zone NP23) is not developed although Sr isotope ratios indicate that the basin was only connected to the Mediterranean for short periods during deposition of the Ihsaniye Formation.

Влияние дноуглубительных работ на морфометрические характеристики, показатели качества воды и донных отложений озера Манжерокское (Республика Алтай)

The paper presents the results of a comprehensive assessment of the current ecological state of the important recreational object, i.e. Lake Manzherokskoye (Maiminsky region of the Altai Republic, the Russian Federation). The investigation was conducted in August 2018, just 2 weeks after the dredging works implemented in the framework of the environmental rehabilitation project. The studied morphometric, hydro/physical and hydro/chemical parameters of the reservoir are evidence of an increase in lake depth (with its maximum more than 2 m, up to 5.66 m) and water volume (more than 2 times, up to 1,16 million m3) that in the future will lead to the improved oxygen regime and the decreased inflow of biogenic matter. Bottom sediments are still represented by soils with a high content of organic carbon (up to 56,2±2.9 mg/dm3) and organic matter (up to 112.3±10,2 mg/dm3); detritus and organic silt (sapropel) dominate in the sediments. In all studied sites and depths of Lake Manzherokskoye, the water was polluted by roiled organic silts. The concentration of suspended solids reached 4.6 g/dm3, whereas transparency (by Secchi disk) dropped up to 0,5 cm. Vertical distribution of suspended substances points to the process of their deposition. Water quality of the lake is estimated as unsatisfactory because of the performed dredging works. Major pollutants of the lake water are phosphates (up to 0,417±0,042 mg/dm3), petroleum products (up to 0,4±0,1 mg/dm3) and organic substances (up to 342,2±35,8 mg O/dm3 by unfiltered water COD); their concentrations exceed MAC significantly. Water quality does not meet the requirements imposed upon the water bodies used for recreational purposes.

ГЕОХИМИЯ МИНЕРАЛЬНЫХ ВОД И ГИДРОГЕННЫХ ОТЛОЖЕНИЙ АНТОНОВСКОГО СЕРОВОДОРОДНОГО МИНЕРАЛЬНОГО ИСТОЧНИКА (О. САХАЛИН)

Original data on the isotopic and chemical composition of mineral waters, cold ground and surface waters, as well as hydrogenic deposits of the Antonovsky manifestation of hydrogen sulfide mineral waters (the coast of the Tatar Strait, Sakhalin Island) are provided in the article. For the first time, data on the content of oxygen and hydrogen isotopes in groundwaters and surface waters, the volumetric activity of radon and the rare-earth elements as well were obtained. Based on automatic monitoring of the physical parameters of the waters, their hydrogeological characteristics were determined and balneological properties were assessed. It has been determined that the mineral waters of the spring are weakly alkaline, hydrocarbonate-chloride calcium-sodium, with TDS of up to 1 g/l. According to isotope data, the genesis of waters is atmospheric, and the circulation time is less than 60 years. The gas composition is dominated by nitrogen of atmospheric genesis (δ15N = 0.0). High contents of organic carbon (Corg. = 56.6 mg/l) are explained by the processes of interaction of groundwaters with organic matter of water-bearing rocks. When organic matter decomposes in the presence of sulfates and without oxygen, hydrogen sulfide is released, giving rise to a number of intermediate and stable sulfur compounds in hydrogenic sediments and bacterial mats. Elemental, sulfide and sulfate forms of sulfur have been determined in the bottom sediments as well as new formations of the mineral spring, using electron microscopy. The interaction of waters with organic matter of rocks plays a significant role in the formation of the elemental composition of hydrogenic and biogenic deposits of the Antonovsky hydrogen sulphide mineral spring and their enrichment with such metals as Zn, Ge, As, Sr, Ba, U, and Th as well. A characteristic feature of mineral waters is the presence of a pronounced positive europium anomaly, which is typical for waters with low Eh values.

Farm systems, soil chemical properties, and clay dispersion in watershed áreas

Abstract: The objective of this work was to evaluate the effect of different farm systems on clay dispersion and its relationship with soil chemical properties and the no-tillage system participatory quality index (IQP), in watershed areas in the west of the state of Paraná, Brazil. The farm systems evaluated were: no-tillage; no-tillage with crop succession; no-tillage with soil disturbance; and conventional system. In addition, the farm systems were evaluated for their IQP. Soil samples were collected at 0.0-0.20-m soil depth, in 40 agricultural areas and in 6 native forests considered as references. The degree of clay dispersion, total organic carbon, pH (CaCl2), exchangeable potassium (K+), available phosphorus (P), exchangeable calcium and magnesium (Ca2++Mg2+), and potential acidity (H+Al3+) were determined. A linear multiple regression model was fitted by the method of least squares. The averages of clay dispersion degree per watershed were compared at 5% probability. The farm systems were compared by Scott-Knott’s test. Soil chemical properties showed a higher influence on clay dispersion than the different farm systems assessed. The no-tillage system alone showed the highest content of organic carbon, which was similar to those of the native areas. The conventional system and the no-tillage system with soil disturbance showed a lower IQP and a higher degree of clay dispersion than the areas with the no-tillage system alone. The IQP allows distinguishing the conventional system from the no-tillage system.