High Organic Matter Content Research Articles

Photochemical transformation of liquid crystal monomers in simulated environmental media: Kinetics, mechanism, toxicity variation and QSAR modeling

Liquid crystal monomers (LCMs) are a new class of emerging pollutants with high octanol-water partition coefficients; however, their transformation behavior and associated risk to environments with high organic matter content has rarely been reported. In this study, we investigated the photodegradation kinetics, mechanism, and toxicity variation of 23 LCMs on leaf wax models (e.g., organic solvents methanol and n-hexane). The order of the photolysis rates of these LCMs were biphenylethyne LCMs > phenylbenzoate LCMs > diphenyl/terphenyl LCMs under simulated sunlight, while the phenylcyclohexane LCMs were resistant to photodegradation. The phenylbenzoate and biphenylethyne LCMs mainly undergo direct photolysis, while the diphenyl/terphenyl LCMs mainly undergo self-sensitized photolysis. The main photolysis pathways are the cleavage of ester bonds for phenylbenzoate LCMs, the addition, oxidation and cleavage of alkynyl groups for biphenylethyne LCMs, and the cleavage/oxidation of chains attached to phenyls and the benzene ring opening for diphenyl/terphenyls LCMs. Most photolysis products remained toxic to aquatic organisms to some degree. Additionally, two quantitative structure-activity relationship models for predicting kobs of LCMs in methanol and n-hexane were developed, and employed to predict kobs of 93 LCMs to fill the kobs data gap in systems mimicking leaf surfaces. These results can be helpful for evaluating the fate and risk of LCMs in environments with high content of organic phase.

Novel strategy for efficient energy recovery and pollutant control from sewage sludge and food waste treatment

Considering the high organic matter contents and pollutants in sewage sludge (SS) and food waste (FW), seeking green and effective technology for energy recovery and pollutant control is a big challenge. In this study, we proposed a integrated technology combing SS mass separation by hydrothermal pretreatment, methane production from co-digestion of hydrothermally treated sewage sludge (HSS) centrate and FW, and biochar production from co-pyrolysis of HSS cake and digestate with heavy metal immobilization for synergistic utilization of SS and FW. The results showed that the co-digestion of HSS centrate with FW reduced the NH4+-N concentration and promoted volatile fatty acids conversion, leading to a more robust anaerobic system for better methane generation. Among the co-pyrolysis of HSS cake and digestate, digestate addition improved biochar quality with heavy metals immobilization and toxicity reduction. Following the lab-scale investigation, the pilot-scale verification was successfully performed (except the co-digestion process). The mass and energy balance revealed that the produced methane could supply the whole energy consumption of the integrated system with 26.2 t biochar generation for treating 300 t SS and 120 t FW. This study presents a new strategy and technology validation for synergistic treatment of SS and FW with resource recovery and pollutants control.

Isopycnal Shoaling Causes Interannual Variability in Oxygen on Isopycnals in the Subarctic Northeast Pacific

AbstractOver 60 years of oceanographic observations from Ocean Station Papa (OSP) in the northeast Pacific indicate faster dissolved oxygen loss than the global average. The greatest negative trends in oxygen concentration occur on isopycnals in the upper water column (σθ = 26.1–26.8 kg m−3, ∼110–200 m) but have considerable uncertainty due to natural variability. In this paper, we use eight Argo profiling floats equipped with optode oxygen sensors to assess the 2008–2016 interannual variability of subsurface dissolved oxygen near OSP. We developed a method using high frequency Conductivity‐Temperature‐Depth data to correct optode profiles for slow response times and used reference profiles from the OSP time series to calibrate the optodes. Response time correction markedly improves subsurface bias caused by slow optode equilibration. Our analysis indicates that episodic shoaling of isopycnals can cause rapid reduction in dissolved oxygen concentration. Changes in ventilation, horizontal mixing, and water mass age are unlikely drivers for the rapid O2 loss events examined. We link dissolved oxygen loss during shoaling events to organic matter export, due to higher concentrations of organic matter and greater respiration rates at shallower depths. Reduced net community production during the “Blob” marine heatwave may have reduced the impact of the second shoaling event examined. Natural variations in dissolved oxygen in these layers provide context for uncertainty estimates of long‐term trends and insight toward the potential for future extreme oxygen minima from the combined impact of the long‐term decline and episodic shoaling.

THE STUDY OF SOME PHYSICAL PROPERTIES OF ANDISOLS IN VARIOUS LAND IN JERNIH JAYA VILLAGE, GUNUNG TUJUH DISTRICT, KERINCI REGENCY

ABSTRACT Although Andisols is the best soil type to support plant growth, overuse of Andisols soil type can degrade soil quality. Gunung Tujuh District of Kerinci Regency's Jernih Jaya Village, there is an Andisols land use location. Soil quality is negatively impacted by land management practices, which disregard land sustainability, soil, and water conservation measures. To understand the physical characteristics of Andisolss in various land uses in Jernih Jaya Village, it is vital to examine the effects of different tillages and land uses. The stages were (1) preparation of primary data (taking soil samples) and secondary data (making maps), (2) survey (preliminary survey and main survey), (3) data processing and interpretation of data resulting from analysis of soil samples and surveys. Based on an examination of various physical attributes of Andisols in different land used within Jernih Jaya Village, Gunung Tujuh District, Kerinci Regency, it could be inferred that the physical properties of Andisols were deemed favorable. The results indicated that the area was used for vegetables, plantations, secondary forests, and paddy fields, with slope classes ranging from 0-3%, 3-8%, and 8-15%, sandy loam with a crumb structure in all land used, high water content, moderate to high total pore space, low to medium volume weight, and high organic matter were all present. When compared to other land uses, paddy fields had the highest organic matter content (22.10%), highest moisture content (124.89%), highest total pore space (79.39%), and lowest bulk density (0.57 g/cm3).

Use of whey through anaerobic codigestion for biomethane production

The whey generated by cheese production is the main by-product generated by the dairy industry, which causes considerable impact on the environment if it is not treated properly. This potential contaminant is mainly due to its high content of organic matter. In recent years, numerous studies have been carried out with the objective of using whey more efficiently, using innovative technological methods for the treatment of wastewater such as the anaerobic digestion method, and thereby being able to obtain derived products such as biogas or biofuels, which generate less environmental impact and develop economic activities. The objective of this study is to collect studies on the use of whey to obtain biogas through the anaerobic digestion technique. The review allowed us to know the wide application of the anaerobic digestion method for the production of biogas from whey and other agri-food substrates, demonstrating the high efficiency of the method in association with biological media in semi-continuous and discontinuous conditions. Likewise, it was also possible to know that the anaerobic co-digestion method is a promising alternative for small and medium-sized industries that could replace fossil fuels with biogas and that in turn contribute to environmental conservation by avoiding pollution and environmental problems due to the effect of the poor serum management.

Surveying the Distribution and Diversity of Predominant Mycobiota in Cultivated and Uncultivated Soils of Zaria, Northwestern Nigeria

Study’s Novelty/Excerpt This study presents a comprehensive survey of the distribution and diversity of soil fungi in cultivated and uncultivated soils of Zaria, Northwestern Nigeria, highlighting their morphological and microscopic characteristics, frequency, and relationship with physicochemical properties. It identifies and quantifies the presence of eight different fungal species, with Aspergillus niger being the most dominant, providing critical insights into the fungal biodiversity of this region. Additionally, the study correlates the richness of soil mycobiota with specific soil properties such as pH, organic matter content, and moisture levels, suggesting that these factors significantly influence fungal diversity and distribution, and recommending further research to assess their impact on soil productivity. Full Abstract Soil fungi are a crucial component of terrestrial ecosystems, playing a vital role as decomposers in nutrient cycles. The diversity of soil fungi serves as an indicator of soil health (favorable/deficient). Understanding soil biodiversity and its biological functioning will help not only in crop yields but also in a healthier society as it directly or indirectly enters the food chain. This study aimed at surveying the distribution and diversity of predominant mycobiota in cultivated and uncultivated soils of Zaria, Northwestern Nigeria. Focusing on their morphological and microscopic characteristics, percentage frequency, and relationship with physicochemical properties. After removing the surface soil, soil samples were randomly collected from two locations at 0-15 cm depths. Fungi were isolated via the dilution method on PDA. Previously established criteria were used to identify eight different fungal species: Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Fusarium spp., Mucor spp., Penicillium spp., Rhizopus spp., and Trichoderma spp. Aspergillus niger was the most dominant species, with a relative frequency of 26%, followed by Fusarium spp. and Rhizopus spp. With 18% and 17%, respectively. Aspergillus fumigatus was the least abundant (2%). The highest fungal isolation frequency (32%) was observed in L1 cultivated soil, closely followed by L2 uncultivated soil (31%), with the lowest in L2 uncultivated soil (16%). Physicochemical analysis indicated that these soils are rich in mycobiota, attributed to a basic pH range of 7.12-9.15, high organic matter content, and optimal moisture levels. Soils with significant organic matter due to litter accumulation, moist deciduous vegetation, and neutral to alkaline pH levels retain considerable moisture content, fostering a rich qualitative and quantitative mycobiota for recycling dead organic matter making nutrients available for suitable utilization. Further research is recommended to evaluate the impact of these isolated fungi on soil productivity, to determine whether their presence has a positive or negative effect.

INFLUENCE OF SOME SELECTED ENVIRONMENTAL FACTORS ON THE NATURAL ATTENUATION OF ATRAZINE IN TROPICAL AGRICULTURAL SOILS

Understanding environmental factors that help to optimize the natural attenuation of atrazine in agricultural soils is necessary to minimize contamination risks and human health risks, as well as support a healthy soil ecosystem. This study, therefore, investigated the influence of pH, temperature, soil organic matter content, often measured as total organic carbon (TOC), and moisture content on atrazine attenuation by soil microbes. Agricultural soil with a history of atrazine application was spiked with the herbicide. The effects of pH (3, 7, 10), moisture content (10%, 15%, 25%), total organic carbon (TOC, 2%, 3%, 4%), and temperature (15°C, 25°C, 45°C) on atrazine attenuation and bacterial count were evaluated at the interval of 30 days each for 60 days of incubation in nutrient agar. The residual concentrations of atrazine attenuation were determined using GC-MS analysis at the interval of 30 days each for 60 days of incubation. The results indicate that higher bacterial counts (Arthrobacter sp.) were observed at neutral pH (7.0) and moderate moisture (10%). At a neutral pH (7), only 52.1% of the initial atrazine concentration remained after 60 days due to attenuation processes. Also, Atrazine natural attenuation increased with increasing TOC where only 25.8% attenuation residual concentration was left at 4% TOC and reached a maximum of 15% moisture content with a residual concentration of 20.13% after 60 days. Similarly, the concentration of atrazine decreased as the temperature increased, with only 29.01% of the residual concentration remaining at 45ºC treatment after 60 days. Statistical analysis revealed significant differences in natural attenuation between 30 and 60 days, but not after 30 days. These findings suggest that natural attenuation was favoured by higher organic matter content and moderate moisture levels, highlighting the importance of soil properties for atrazine fate in tropical soils and emphasizing the importance of studying natural attenuation processes as a viable strategy, particularly in tropical agricultural settings to minimize unnecessary contamination of soil to ensure a healthy and safe agricultural environment.

The redistribution process of As(Ⅲ) and Fe(Ⅱ) caused by As/Fe ratio, organic matter, and co-existing ions: Co-precipitation and co-oxidation

The contamination of arsenic (As) in aqueous environments has drawn widespread attention, and iron compounds may largely alter the migration ability of As. However, the stability of As(III) in Fe-As system with the intervention of organic matter (OM) remains unclear. Herein, we had explored the co-precipitation and co-oxidation processes of As-Fe system by using batch experiments combined with Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) in this research. The precipitation quantity of As(III) increased (28.85–92.41 %) when the As/Fe ratio decreased, and increased (24.20–64.20 %) with pH increased. The main active substance for oxidizing As(III) was H2O2, which was produced in the As-Fe system. FTIR and XPS revealed that As(III) was first oxidized in neutral, and then absorbed and enteredthe interior of Fe(OH)3 colloids. But under alkaline conditions, As(III) was adsorbed by Fe (Oxyhydr) oxides firstly, and then oxidized. The intervention of OM would inhibit the redistribution process of As(III) in aqueous environments. Functional groups and unsaturation of the carbon chain were the dominant factors that affected the precipitation and oxidation processes of As(III), respectively. Co-existing ions (especially PO43-) also signally affected the precipitation quantity of As(Ⅲ) in the system and, when coexisting with OM, could exacerbate this process. The influence of co-existing ions on the redistributive process of As(III) in the As-Fe system with/without OM were as follows: PO43- > SO42- > mixed ions > SiO32-. Moreover, high concentration of OM and PO43- might lead to morphological alterations of As, acting as a threat to aqueous environments. In summary, the present findings were to further understand and appreciate the changes of As toxicity in the aqueous environments. Particularly, the coexistence of OM and As can potentially increase the risk to drinking water safety.

Биологическое загрязнение почв побочными продуктами животноводства

By-products of animal husbandry (BPAH) such as manure, manure effluents (ME) are widely used as organic fertilizers. The main disadvantage of the appropriate fertilizers is the high content of microorganisms (MO) untypical to uncontaminated natural environments, including pathogenic ones. Currently used natural methods of BPAH neutralization can significantly reduce the risks of transferring pathogenic and opportunistic MO into fertilized soil, but do not completely exclude them. The study examined the effects of long-term (more than 7 years) introduction of a neutralized liquid fraction (LF) of pork ME and cattle ME on the chemical composition and sanitary and hygienic condition of the soil of arable fields and wooded areas located at 500 m from the boundaries of the fields. Prolonged application of LF led to an increase in the content of organic matter, mobile phosphorus, potassium and sulfur, an increase in the amount of absorbed bases, a decrease in metabolic acidity in arable land compared with adjacent forest areas. However the sanitary condition of both arable land and adjacent territories deteriorated significantly. A significant increase in the total microbial number (TMN) was revealed in all soil samples in comparison to the normative indicators. Particularly high values of TMN were found in soil fertilized with cattle manure. The corresponding soil was characterized by the highest content of organic matter and neutral reactions of the environment, which provided favorable conditions for the active development of saprophytic microbiota. Fresh faecal contamination was detected in all selected soil samples. Soils are characterized as highly polluted. According to the indicators of the index Escherichia coli, Enterococcus and Clostridium perfringens, the soils of all studied sites are moderately dangerous. Higher values of the corresponding indices were found in arable land fertilized by the LF of pork farms and in the territories adjacent to arable land. In the course of sanitary and bacteriological studies, eggs of helminthes were not found in the soil.

Female oviposition preferences and larval behavior of the Aedes aegypti mosquito (Linnaeus, 1762) exposed to predator cues (Odonata: Libellulidae)

The reproductive success of mosquitoes is heavily influenced by females' ability to select suitable oviposition sites for the proper development of their offspring. Many of these potential habitats may harbor predators, and the detection of these predators is crucial for assessing the risk of predation, which can, in turn, influence the behavior of the prey. However, there are often trade-offs to consider, which can impact the life history of these organisms. In our study, we investigated the oviposition preferences and larval behavioral responses of the Aedes aegypti mosquito when exposed to cues from predators and the actual presence of predation by Libellulidae (Odonata) larvae. We observed the mosquito's choices regarding oviposition with and without predation cues for a duration of ten weeks, following 48 hours of exposure. Additionally, we measured larval behavior across various treatments, including those with predation cues, predator cues, the presence of larvae, and controls with only water. Our findings revealed that the highest preference for oviposition occurred in containers with high organic matter content, regardless the presence of both predator cues and actual predators. Furthermore, we noted significant changes in larval behavior in response to predation cues, including evasive behaviors. When facing the risk of predation, larvae spent more time near the container's edges and exhibited discrete feeding behaviors or avoidance of the risk of predation. Conversely, in the absence of predation risk, larvae explored the entire container, swimming vigorously. These results highlight the significance of anti-predatory behaviors triggered by the recognition of predation cues in the context of Ae. aegypti's reproductive success.

Pedological factors affecting pesticide retention in a series of tropical volcanic ash soils in the French West Indies

Specific pedoclimatic conditions in tropical environments have a considerable impact on pesticide fate. Tropical volcanic soils result from specific pedogenesis processes linked to successive volcanic projections; they are characterised by acidic conditions, high organic matter content, a specific mineralogical composition and the presence of organo-mineral complexes. The retention of pesticides in these soils is therefore often high but variable depending on the associated molecules and soil properties. Nevertheless, knowledge of pesticide sorption in these soils remains limited, and knowledge of the desorption process is scarce. The objectives of this work were to study the variability of the sorption and desorption coefficient of four pesticides currently used in banana and sugarcane crops on a set of representative tropical soils developed on volcanic ash (Guadeloupe, French West Indies). Adsorption and desorption isotherms were analysed for three ionizable pesticides (2,4-D, mesotrione, glyphosate) and a hydrophobic pesticide (difenoconazole) on ten soil samples from five soil profiles: one silandic andosol, one vitric andosol, two nitisols and one ferralsol. For ionizable pesticides, soil pH appears to be a first-order discriminating factor of the sorption capacity, and the organic carbon content appears to have a lesser impact on 2,4-D. For a strongly hydrophobic pesticides such as difenoconazole, the organic carbon content plays a major role in sorption. Desorption hysteresis has been observed regardless of the soils and the molecules considered, and tropical volcanic soils seem to be conducive to adsorption but show low to moderate release. The silandic andosol, which has the greatest sorption, buffers the dissemination of pesticides towards surface and groundwaters but also increases the risk of long-term contamination in the case of molecules that degrade slowly. Moreover, our results highlight that agronomic practices, such as liming, have a major impact on the sorption coefficient of pesticides and must be considered for when predicting sorption in a tropical volcanic context.

Novel herbicide flusulfinam: absolute configuration, enantioseparation, enantioselective bioactivity, toxicity and degradation in paddy soils.

Flusulfinam, a novel chiral herbicide, effectively controls Echinochloa crusgalli and Digitaria sanguinalis in paddy fields, indicating significant potential for practical agricultural applications. However, limited information is available on flusulfinam from a chiral perspective. A comprehensive evaluation of the enantiomeric levels of flusulfinam was performed. Two enantiomers, R-(+)- and S-(-)-flusulfinam, were separately eluted using a Chiralcel OX-RH column. The bioactivity of R-flusulfinam against the two was 1.4-3.1 fold that of Rac-flusulfinam against two weed species. R-flusulfinam toxicity to Danio rerio larvae and Selenastrum capricornutumwere was 0.8- and 3.0-fold higher than Rac-flusulfinam, respectively. Degradation experiments were conducted using soil samples from four Chinese provinces. The findings indicated that S-flusulfinam (half-life T1/2 = 40.8 days) exhibits preferential degradation than R-flusulfinam (T1/2 = 46.2-57.8 days) in the soils of three provinces. Under anaerobic conditions, soil from Anhui exhibited preferential degradation of R-flusulfinam (T1/2 = 46.2 days) over S-flusulfinam (T1/2 = 63 days). Furthermore, two hydrolysis products of flusulfinam (M299 and M100) are proposed for the first time. The enantioselective bioactivity, toxicity and degradation of flusulfinam were investigated. Our findings indicate that R-flusulfinam is an extremely effective and low-toxicity enantiomer for the tested species. The soil degradation test indicated that the degradation of flusulfinam was accelerated by higher organic matter content and lower soil pH. Furthermore, microbial communities may play a crucial role in driving the enantioselective degradation processes. This study lays the groundwork for the systematic evaluation of flusulfinam from an enantiomeric perspective. © 2024 Society of Chemical Industry.

Production of low-sulfur fuels from catalytic pyrolysis of waste tires using formulated red mud catalyst

Waste tires (WT) are produced in millions of tons per annum and their safe disposal is always a major environmental challenge because of fire hazards and the increasing cost of landfills. WT has high organic matter content that can be converted into fuels and chemicals if suitable technologies can be developed. Herein we report the in situ catalytic pyrolysis of WT using formulated red mud catalyst to produce low sulfur fuel that can be fractionated or can be used without fractionation. The in situ catalytic pyrolysis was conducted at 450–550 °C using formulated red mud catalyst. The yield of pyrolysis liquids ranged from 35 to 40 wt%. The liquid was very rich in limonene and long chain aliphatic hydrocarbons. The catalyst was effective in removing the sulfur compounds in the oil through reactive adsorption desulfurization mechanism. The sulfur species reacted with hematite, calcite, sodium hydroxide, and zinc oxide to form sulfides and were retained in the catalyst. The minimum sulfur content of the catalytic pyrolysis oil was 0.38 wt%. After catalyst regeneration in air through combustion, the catalyst activity was restored, and the catalyst was reused.

Assessing sediment quality at tropical mangrove areas for using as reference sites in ecotoxicological bioassays

The sediment of five mangrove in Pernambuco/Brazil was investigated to find a reference site for toxicity bioassays. Sediment characteristics, metal levels, and toxic effects on the nauplius of the copepod Tisbe biminiensis were studied. The sediment was composed by terrigenous muds and siliciclastic sands with medium to high organic matter contents. The FeAs association show most of the high concentrations and positive correlation among its constituents in the south. In the north, the Ca-Sr-La association is higher and exhibits positive correlation among its components that usually found in carbonate rocks. Very intense toxic effects were observed, mainly in the south, with >70 % reductions in development. As and Hg were positively correlated with mortality and decrease in development. The sediment quality at studied mangroves prevent their use as a reference site in bioassays. These could be linked to the direct/perennial contribution of geogenic sources associated with anthropogenic environmental impacts.

WATER RESOURCES OF THE KHOROSTKIV TERRITORIAL COMMUNITY: ECOLOGICAL STATUS, WATER USE PROBLEMS, OPTIMISATION MEASURES

The article analyses the ecological state of surface water resources of the Khorostkiv territorial community (ТС). According to the results of laboratory tests, pathogenic microorganisms, bacteriological indicators exceeding the regulatory requirements, faecal contamination and high content of organic matter were detected in the surface water bodies of the Khorostkiv TC. In addition to the pollution of surface water bodies in the Khorostkiv TC, an important environmental problem worth paying attention to is the lack of sanitary protection and water protection zones for rivers and ponds, as well as the littering of the coastal strip. It was found that the water supply network of the Khorostkiv territorial community includes only the water supply network of the town of Khorostkiv (30 km, unsatisfactory condition), since there are no centralised water supply systems in rural settlements. In the sources of centralised water supply in Khorostkiv, the levels of ammonium nitrogen and colour are exceeded. Hydrochemical analysis of water samples from private wells in Khorostkiv and the villages of Peremyliv and Khlopivka confirmed compliance with the requirements of SanR&R № 400. The volume of daily water consumption and water disposal was analysed. The main sources of pollution of the community's water resources and the volume of wastewater discharges were identified. Priority areas for improving the ecological state of water resources of the Khorostkiv community are substantiated. Keywords: surface water, groundwater, pollutants, water supply, water disposal, territorial community (ТС).

Is it necessary to increase the maize planting density in China?

Increasing the maize planting density is considered a potential approach for increasing the grain yield in China, but there is no consensus regarding its yield-increasing effect and the influence of specific factors. Thus, we established a database (2721 pairs of data from 187 publications) to quantify the effects of increasing the maize planting density on the phenotypic traits and yield, to determine an appropriate maize planting density for each planting area, and to quantify the effects of environmental factors and agricultural imputs on the outcomes of increasing the planting density. We found that increasing the planting density increased the individual competition among maize plants, with negative effects on their growth, but the grain yield increased by 11.18–13.43 % due to the increased population biomass. Using the database, we found large differences in the optimal density and peak grain yield among maize planting areas, and the factors that caused these differences were analyzed based on subgroup analysis. Field management practices significantly influenced the outcomes of increasing the planting density. In particular, higher agricultural inputs (irrigation amount, and nitrogen and phosphorus application rates) enhanced the positive effect of increasing plant density on the optimal plant density and peak grain yield. In addition, the effects of increasing the planting density were significantly influenced by environmental (climate and soil) factors. When the mean annual temperature was 7–14°C and the mean annual precipitation was 400–800 mm, the yield and maximum peak yield were highest in relatively fertile (high total nitrogen, available nitrogen, and soil organic matter contents) and neutral (pH 6–8) soils. Our results highlight the need to increase the current maize planting density and provide a scientific basis for determining reasonable planting densities for different maize growing areas in China.

Molecular biological mechanism of fillers with surface micro-electric field to enhance biodegradation of kitchen-oil wastewater

The kitchen-oil wastewater is characterized by a high concentration of organic matter, complex composition and refractory pollutants, which make wastewater treatment more difficult. Based on the study of using micro-electric field characteristic catalyst HCLL-S8-M to enhance the electron transfer between microorganisms in kitchen-oil wastewater which further improved the COD removal rate, we focus on the microbial community, intracellular metabolism and extracellular respiration, and make an in-depth analysis of the molecular biological mechanisms to microbial treatment in wastewater. It is found that electroactive microorganisms are enriched on the material surface, and the expression levels of cytochrome c and riboflavin genes related to electron transfer are up-regulated, confirming that the surface micro-electric field structure could enhance the electron transfer between microbial species and improve the efficiency of wastewater degradation. This study provides a new idea for the treatment of refractory organic wastewater.

Soil type and temperature determine soil respiration seasonal dynamics in dairy grassland

Soil respiration rates (Rs) were measured in New Zealand dairy grassland.Both season and soil type significantly affected Rs.Soil temperature and soil type dominated overall Rs.Soil respiration (Rs), the CO2 release from root respiration and microbial metabolism, affects global soil carbon storage and cycling. Only few studies have looked at Rs in the southern hemisphere, especially regarding the interaction between soil type and environmental factors on Rs in dairy grassland. We investigated the relationship between Rs and soil temperature (Ts), soil water content (SWC), soil type, and other environmental factors based on summer and winter measurements at four sites in New Zealand. Across sites, soil respiration rates ranged from 0.29 to 14.58 with a mean of 5.38 ± 0.13 (mean ± standard error) µmol CO2 m−2 s−1. Mean summer Rs was 86.5% higher than mean winter Rs, largely driven by organic/gley and pumice soils while ultic soils showed very little seasonal temperature sensitivity. Overall mean Rs in organic/gley soils was 108.0% higher than that in ultic soils. The high Rs rate observed in organic/gley was likely due to high soil organic matter content, while low Rs in ultic and pallic soils resulted from high clay content and low hydraulic conductance. Soil temperature drove overall Rs. Our findings indicate that soil type and soil temperature together best explain Rs. This implies that a mere classification of land use type may be insufficient for global C models and should be supplemented with soil type information, at least locally.

Limited sensitivity of permafrost soils to heavy rainfall across Svalbard ecosystems

Together with warming air temperatures, Arctic ecosystems are expected to experience increases in heavy rainfall events. Recent studies report accelerated degradation of permafrost under heavy rainfall, which could put significant amounts of soil carbon and infrastructure at risk. However, controlled experimental evidence of rainfall effects on permafrost thaw is scarce. We experimentally tested the impact and legacy effect of heavy rainfall events in early and late summer for five sites varying in topography and soil type on the High Arctic archipelago of Svalbard. We found that effects of heavy rainfall on soil thermal regimes are small and limited to one season. Thaw rates increased under heavy rainfall in a loess terrace site, but not in polygonal tundra soils with higher organic matter content and water tables. End-of-season active layer thickness was not affected. Rainfall application did not affect soil temperature trends, which appeared driven by timing of snowmelt and organic layer thickness, particularly during early summer. Late summer rainfall was associated with slower freeze-up and colder soil temperatures the following winter. This implies that rainfall impacts on Svalbard permafrost are limited, locally variable and of short duration. Our findings diverge from earlier reports of sustained increases in permafrost thaw following extreme rainfall, but are consistent with observations that maritime permafrost regions such as Svalbard show lower rainfall sensitivity than continental regions. Based on our experiment, no substantial in-situ effects of heavy rainfall are anticipated for thawing of permafrost on Svalbard under future warming. However, further work is needed to quantify permafrost response to local redistribution of active layer flow under natural rainfall extremes. In addition, replication of experiments across variable Arctic regions as well as long-term monitoring of active layers, soil moisture and local climate will be essential to develop a panarctic perspective on rainfall sensitivity of permafrost.

The Existence of Macroalgae in Indonesia: Unlocking the Nutritive Potential for Sustainable Beef Production

Abstract Assessment of the existence of macroalgae and revealing the chemical composition to investigate the potential usage for feed to support sustainable beef production has been conducted in Indonesian prominent livestock production area specifically Lombok, Bali, Yogyakarta, Lampung and Bengkulu. These regions host numerous seaweed production centres, while others hold the capacity to develop into seaweed cultivation zones. To assess the existence, utilisation, and accessibility of macroalgae in each region, observations and interviews were conducted. Subsequently, dominant macroalgae species were sampled and subjected to proximate analysis to determine their nutritional profiles. The results showed that the dominant macroalgae observed included red algae (Rhodophyta) like Eucheuma sp., Gracilaria sp., and Acanthophora sp., green algae (Chlorophyta) such as Ulva sp. and Caulerpa sp., and the brown alga (Phaeophyta) Sargassum sp. The dominant macroalgae found in all five observation sites with high abundance were Sargassum sp., Gracilaria sp., and Eucheuma cottonii. Ulva sp. and Eucheuma spinosum were present at four sites, while Acanthophora sp. and Caulerpa sp. were found at three sites. The dry matter content of the macroalgae ranged from 9.92% to 17.01%, with the highest values observed in the Eucheuma group (14.11%-17.01%). This was followed by Sargassum sp. (12.55 ± 2.40%), Ulva sp. (12.28 ± 2.33%), and Gracilaria sp. (11.09 ± 3.79%). Caulerpa sp. exhibited the lowest dry matter content (9.92 ± 1.29%). The crude protein (CP) content varied both within and between groups of algae species and observation sites. Gracilaria sp. exhibited the highest CP content (13.55 ± 0.16%), followed by Caulerpa sp. (11.87 ± 2.22%), Sargassum sp. (8.98 ± 0.42%), and Ulva sp. (6.98 ± 0.94%). The mineral content of the macroalgae was noticeably high, which is reflected in the low organic matter content. Ulva sp. had the highest organic matter content (80.17%), followed by Sargassum sp. (70.55%), Gracilaria sp. (66.53%), Caulerpa sp. (47.61%), and Eucheuma cottonii (43.50%). The readily available seaweed in this study tend to exhibit moderate to high protein and mineral content, making it a promising partial replacement or supplement for conventional feed, potentially contributing to sustainable beef production. Gracilaria sp., the most readily available seaweed, high in nutrient content with the potential to partially replace conventional feed protein sources. Its abundance of vitamins and minerals may enrich the overall value of the feed.