Breakdown Of Organic Matter Research Articles

A new species of Erinaceusyllis (Annelida: Syllidae) discovered at a wood-fall in the eastern Clarion-Clipperton Zone, central Pacific Ocean.

In the deep sea, organic falls provide temporary localized enrichments of organic matter to the otherwise nutrient-poor abyssal seafloor. Areas where organic falls land become ephemeral patches of increased biodiversity. Often rich in opportunistic species which are tolerant to the sulfidic environment formed from anaerobic breakdown of organic matter. On a wood-fall at abyssal depths in the eastern Clarion-Clipperton Zone, the novel species Erinaceusyllis simonlledoi (Annelida: Syllidae) was discovered in high abundance. This study entails the first description of a novel syllid species found in high density on a naturally occurring organic fall. Phylogenetic position was investigated using three genetic markers (16S, 18S, COI) and morphology was studied through light- and scanning electron microscopy. Genetic data and morphological analysis supported placement in the syllid genus Erinaceusyllis. Distinguishing features were lack of eyes, dorsal brooding of one egg per egg-bearing segment, lack of visible papillae across the body, incomplete fusion of palps, bidentate chaetae, as well as pyriform antennae and tentacular cirri. Erinaceusyllis simonlledoi sp. nov. is highly similar to a species found on hydrothermal vents belonging to the closely related genus Sphaerosyllis. The similarity between the two species, as well as findings of unspecified Sphaerosyllis species in various types of sulfidic habitats evoke questions of a possible syllid lineage adapted to sulfidic environments.

Thermophilic and mesophilic anaerobic digestion of soybean molasses: A performance vs. stability trade-off

One of the factors that has a direct impact on anaerobic digestion is the applied organic loading rate (OLRA). Increasing OLRA can boost methane production but can also cause process failure. As a result, establishing the appropriate OLRA for the procedure is critical. This study evaluated the effect of increasing the OLRA using soybean molasses in a thermophilic anaerobic reactor (R-Thermo), as well as the effect of feeding strategy and co-processing with okara. Furthermore, the performance versus stability trade-off between R-Thermo and mesophilic anaerobic digestion (R-Meso) was investigated. The increase of OLRA from 10 to 15 and 20 kg-COD/m³/d led to a decrease in COD removal efficiency (90, 86, and 75%), methane yield (12.0, 11.6, and 9.9 mol-CH4/kg-COD) and an increase in total volatile acids concentration (251, 456, and 1393 mg-HAc/L, respectively). At 15 kg-COD/m³/d, R-Meso performed similarly to R-Thermo, and at 20 kg-COD/m3/d, R-Meso outperformed (81% COD removal efficiency, 9.3 mol-CH4/kg-CODrem and 154.5 mol-CH4/m3/d). Temperature greatly influenced the distribution of metabolic pathways, as shown by thermodynamic and kinetic analyses, thus impacting bacterial diversity. At 55 °C, amongst the bacterial genera, Tepidiphilus stood out (>28.2%), followed by Acetomicrobium, Coprothermobacter and Candidatus_Caldatribacterium. The OLRA clearly impacted the archaeal community; Methanothermobacter (77.4%) was favored over Methanosarcina (14.8%). Under thermophilic temperature, it seems that syntrophic acetate oxidation (SAO) bacteria might have competed for substrate with acetoclastic methanogens, while in R-Meso microorganisms responsible for the initial steps of organic matter breakdown, such as members of the Firmicutes and Proteobacteria phyla (at least 67%), were dominant. In summary, R-Meso, characterized by a more uniform distribution of metabolic pathways, as well as a diverse and well-adapted microbial consortium, have exhibited enhanced stability and outperformed R-Thermo at high-loads.

Ground beetle trophic interactions alter available nitrogen in forest soil

It is generally held that microbes exert primary control over nitrogen availability in temperate forests. Yet the role of soil and litter‐dwelling invertebrates to provide additional control via the breakdown of organic matter is an area of current exploration. Through trophic interactions within soil food webs, predators may indirectly affect prey with cascading effects on litter breakdown and nitrogen availability. The importance of these interactions, however, may be context‐dependent, varying with the stage of forest development and associated decomposer species composition given that young and old forests have vast differences in nitrogen availability, vegetation litter, soil properties and invertebrate functional groups. We examined ground beetle control over soil nitrogen and soil properties using a 68‐day mesocosm experiment that manipulated trophic structure (omnivore + predator beetles, predator beetles, and no beetles) in a young and old forest stand in the northeastern United States. In the young forest, net nitrogen mineralization decreased under predator + omnivore and the bulk soil C:N ratio in the old forest. However, we found no response in either forest context to the predator only treatment. Our study demonstrates the potential for ground beetles to strongly impact nitrogen availability and soil properties in forest ecosystems. Therefore, animal trophic interactions and their contexts must be included in our paradigm of nutrient cycles in temperate forests.

Gains in soil carbon storage under anthropogenic nitrogen deposition are rapidly lost following its cessation.

In the Northern Hemisphere, anthropogenic nitrogen (N) deposition contributed to the enhancement of the global terrestrial carbon (C) sink, partially offsetting CO2 emissions. Across several long-term field experiments, this ecosystem-level response was determined to be driven, in part, by the suppression of microbial activity associated with the breakdown of soil organic matter. However, since the implementation of emission abatement policies in the 1970s, atmospheric N deposition has declined globally, and the consequences of this decline are unknown. Here, we assessed the response of soil C storage and associated microbial activities, in a long-term field study that experimentally increased N deposition for 24 years. We measured soil C and N, microbial activity, and compared effect sizes of soil C in response to, and in recovery from, the N deposition treatment across the history of our experiment (1994-2022). Our results demonstrate that the accumulated C in the organic horizon has been lost and exhibits additional deficits 5 years post-termination of the N deposition treatment. These findings, in part, arise from mechanistic changes in microbial activity. Soil C in the mineral soil was less responsive thus far in recovery. If these organic horizon C dynamics are similar in other temperate forests, the Northern Hemisphere C sink will be reduced and climate warming will be enhanced.

Sustainable pre-treatment of tempeh industry wastewater: Efficiency of vermifiltration in pollutant mitigation and compost production

This study investigated the efficacy of vermifiltration (VF) as a sustainable pre-treatment method for tempeh industry wastewater. Three lab-scale VF reactors using different earthworm feeds - cow dung (VF-1), tofu dregs (VF-2), and a combination of both (VF-3) - were used to evaluate their ability to reduce chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), and total suspended solids (TSS), as well as pH. VF-3 exhibited superior performance, achieving reductions of 94.51 % in COD, 95.59 % in BOD₅, and 88.59 % in TSS with maintaining pH values between 6.73 and 6.87. The resulting vermicompost (VC) had high nutrient content, particularly in the VF-3 reactor, with values of 7.66 % C-organic, 1.19 % nitrogen (N), and a C/N ratio of 10.33, phosphate (P) 1.65 %, and potassium (K) of 0.37 %. Additionally, significant earthworm growth was noted in VF-3, suggesting enhanced organic matter breakdown. These results indicate that VF technology not only effectively reduces pollutants in wastewater but also produces nutrient-rich compost, offering a dual benefit for sustainable wastewater management in the tempeh industry.

Herbicides Effects on Soil Functions: A Review

This review explores the impact of herbicides on soil functions, offering a detailed analysis of how these chemicals influence soil health. Herbicides, commonly used for controlling unwanted plants, often disturb the balance of soil ecosystems by altering microbial diversity, disrupting nutrient cycling, and affecting organic matter breakdown. The findings show that herbicides can either inhibit or stimulate soil microbial activities, depending on their type, concentration, and environmental conditions. While some herbicides have minimal short-term effects on soil respiration and microbial activity, others significantly reduce soil enzyme activities, slow down nitrogen mineralization, and disrupt beneficial microbial relationships, such as those involving mycorrhizal fungi. The persistence of herbicide residues in soil presents further challenges, with potential risks of contaminating soil and groundwater. It highlights the importance of using herbicides carefully, considering both their effectiveness in weed control and their long-term effects on soil health. However, the paper concludes with an evaluation of the ecological and evolutionary impacts of herbicides on soil microbial communities, calling for further research to fully understand these complex interactions.

Temperature dependence of leaf breakdown in streams differs between organismal groups and leaf species.

Increased temperatures are altering rates of organic matter (OM) breakdown in stream ecosystems with implications for carbon (C) cycling in the face of global change. The metabolic theory of ecology (MTE) provides a framework for predicting temperature effects on OM breakdown, but differences in the temperature dependence of breakdown driven by different organismal groups (i.e., microorganisms vs. invertebrate detritivores) and litter species remain unresolved. Over two years, we conducted 12 60-day leaf litterbag incubations in 20 headwater streams in the southern Appalachian Mountains (USA). We compared temperature dependence (as activation energy, Ea) between microbial and detritivore-mediated breakdown, and between a highly recalcitrant (Rhododendron maximum) and a relatively labile (Acer rubrum) leaf species. Detritivore-mediated breakdown had a higher Ea than microbial breakdown for both leaf species (Rhododendron: 1.48 > 0.56 eV; Acer: 0.97 > 0.29 eV), and Rhododendron breakdown had a higher Ea than Acer breakdown for both organismal groups. Similarly, the Ea of total (coarse-mesh) Rhododendron breakdown was higher than the Ea of total Acer breakdown (0.89 > 0.52 eV). These effects for total breakdown were large, implying that the number of days to 95% mass loss would decline by 40% for Rhododendron and 26% for Acer between 12°C (our mean temperature value) and 16°C (+4°C, reflecting projected increases in global surface temperature due to climate change). Despite patterns in Ea, overall breakdown rates were higher for microbes than detritivores, and for Acer than Rhododendron over most of our temperature gradient. Additionally, the Ea for a subset of the microbial breakdown data declined from 0.40 to 0.22 eV when fungal biomass was included as a model predictor, highlighting the key role of fungi in determining the temperature dependence of litter breakdown. Our results imply that, as streams warm, routing of leaf litter C to detritivore-mediated fates will increase faster than predicted by previous studies and MTE, especially for labile litter. As temperatures rise, earlier depletion of autumn-shed, labile leaf litter combined with rapid breakdown rates of recalcitrant litter could exacerbate seasonal resource limitation and alter carbon storage and transport dynamics in temperate headwater stream networks.

Characterization of methanogens from landfill samples: implications for sustainable biogas production

This case study aimed to isolate and identify methanogenic bacteria from landfill soil, mud, and leachate samples to assess their role in anaerobic digestion and biogas production. Anaerobic digestion involves the breakdown of organic matter by a diverse group of bacteria under oxygen-free conditions, resulting in the production of methane and carbon dioxide. The collected samples from the landfill were cultured in a modified mineral salt medium (MSM). Microscopic observations revealed distinct coccus and bacillus morphologies of the isolated methanogenic bacteria. Gas production experiments and substrate utilization studies identified two types of methanogens. Methanosarcina sp., which utilized acetate and methanol for methane production, and Methanobacterium sp., utilizing hydrogen and carbon dioxide, as well as acetate. Scanning electron microscope (SEM) analysis confirmed the different morphotypes of the isolated methanogens. The study findings demonstrated the presence of diverse methanogens in the landfill environment, contributing to anaerobic digestion and biogas production.

High value-added chemical production through anaerobic codigestion of corn straw with a microbial consortium, cow manure and cow digestion solution

ObjectivesThis study investigated the codigestion of corn straw (CS) with cow manure (CM), cow digestion solution (CD), and a strain consortium (SC) for enhanced volatile fatty acid (VFA) production. The aims of this study were to develop a sustainable technique to increase VFA yields, examine how combining microbial reagents with CS affects VFA production by functional microorganisms, and assess the feasibility of improving microbial diversity through codigestion. MethodsBatch experiments evaluated VFA production dynamics and microbial community changes with different combinations of CS substrates with CM, CD, and SC. Analytical methods included measuring VFAs by GC, ammonia and chemical oxygen demand (COD) by standard methods and microbial community analysis by 16S rRNA gene sequencing. ResultsCodigesting CS with the strain consortium yielded initial VFA concentrations ranging from 0.6 to 1.0 g/L, which were greater than those of the other combinations (0.05–0.3 g/L). Including CM, and CD further increased VFA production to 1.0–2.0 g/L, with the highest value of 2.0 g/L occurring when all four substrates were codigested. Significant ammonium reduction (194–241 mg/L to 29–37 mg/L) and COD reduction (3310–5250 mg/L to 730–1210 mg/L) were observed. Codigestion with CM and CD had greater Shannon diversity indices (3.19–3.24) than did codigestion with the other consortia (2.26). Bacillota dominated (96.5–99.6 %), with Clostridiales playing key roles in organic matter breakdown. ConclusionsThis study demonstrated the feasibility of improving VFA yields and harnessing microbial diversity through anaerobic codigestion of lignocellulosic and animal waste streams. Codigestion substantially enhanced VFA production, which was dominated by butyrate, reduced ammonium and COD, and enriched fiber-degrading and fermentative bacteria. These findings can help optimize codigestion for sustainable waste management and high-value chemical production.

Bacteria-Like Gaiella Accelerate Soil Carbon Loss by Decomposing Organic Matter of Grazing Soils in Alpine Meadows on the Qinghai–Tibet Plateau

The alpine meadows of the Qinghai–Tibet Plateau have significant potential for storing soil carbon, which is important to global carbon sequestration. Grazing is a major threat to its potential for carbon sequestration. However, grazing poses a major threat to this potential by speeding up the breakdown of organic matter in the soil and releasing carbon, which may further lead to positive carbon-climate change feedback and threaten ecological security. Therefore, in order to accurately explore the driving mechanism and regulatory factors of soil organic matter decomposition in grazing alpine meadows on the Qinghai–Tibet Plateau, we took the grazing sample plots of typical alpine meadows as the research object and set up grazing intensities of different life cycles, aiming to explore the relationship and main regulatory factors of grazing on soil organic matter decomposition and soil microorganisms. The results show the following: (1) soil microorganisms, especially Acidobacteria and Acidobacteria, drove the decomposition of organic matter in the soil, thereby accelerating the release of soil carbon, which was not conducive to soil carbon sequestration in grassland; (2) the grazing triggering effect formed a positive feedback with soil microbial carbon release, accelerating the decomposition of organic matter and soil carbon loss; and (3) the grazing ban and light grazing were more conducive to slowing down soil organic matter decomposition and increasing soil carbon sequestration.

Synthesis of Iron Nanoparticle Using Polyphenol Bioreductor from Red Pomegranate Extract

Nano zero valent iron (nZVI) has been utilized for environmental remediation and raw water treatment. The NaBH4 reductor, utilized in iron nanoparticle synthesis, yielded easily oxidized and agglomerated material. Using polyphenol as a bioreductor resulted in a more stable material. The purpose of this research is to synthesize and compare quality of nZVI utilizing NaBH4 (C-nZVI) to nZVI utilizing polyphenol from spent tea and the peel of pomegranate (G-nZVI) and determine the efficiency of pomegranate peel G-nZVI in reducing dissolved organic matter. The iron nanoparticle was synthesized by reducing FeCl3 salt in a water solvent. C-nZVI material was generated as a black powder, whereas G-nZVI materials were black flakes. The band gap energy values of these three materials indicate that they have reached the nanoscale. All three materials had entire nZVI unitary groups based on its FTIR spectrums. The X-ray diffractogram did not clearly show the core of the phase crystals. The G-nZVI from the peel of pomegranate had a greater distribution and mean material size than the spent tea G-nZVI. Both zeta potentials G-nZVI demonstrate that the materials were stable in the aqueous medium. After two hours of incubation, G-nZVI pomegranate peel at room temperature and dark conditions achieved an optimal dissolved organic matter breakdown rate of 98%.

Evaluating the Performance of Modified Geo-Synthetic Clay Liners

Waste products from human activity must always be controlled. Reusing some garbage is possible. But a lot of rubbish that could be more useful needs to be disposed of to protect the environment. Landfilling is one popular form of disposal. The most frequent issues with landfills are groundwater contamination and environmental deterioration, brought on by rainfall and leachate generated during the breakdown of organic materials. A landfill's liner is crucial to stop leachate migration and groundwater contamination. Since their development in 1986, Geo-Synthetic Clay Liners (GCLs) have gained popularity as a barrier solution for municipal solid waste landfills. In this study, fly ash and Kaolinite, two waste materials, are combined with bentonite in different percentages 10–30% and 50%, respectively to evaluate their potential usage as liner materials. Bentonite, in combination, is anticipated to function as a low permeability, self-healing, hydraulic barrier due to these swelling qualities.

The Role of Fungi in Food Production and Processing

Fungi play an important and multifaceted role in the production and processing of food, influencing various stages from cultivation to consumption. This paper explores the complex relationship between fungi and food systems, highlighting their diverse contributions. Firstly, fungi serve as essential agents in food cultivation, aiding in the breakdown of organic matter and the recycling of nutrients, and promoting plant growth through symbiotic relationships. Moreover, fungi such as yeasts and molds are integral to fermentation processes, yielding a wide array of fermented foods and beverages with unique flavors and textures. Additionally, fungi are indispensable in the creation of enzymes and bioactive compounds utilized in food processing, enhancing the nutritional value, shelf life, and safety. However, certain fungal species pose significant challenges as food spoilage agents and mycotoxin producers, necessitating stringent quality control measures. Understanding the intricate interplay between fungi and food systems is essential for optimizing food production, ensuring food security, and mitigating the risks associated with fungal contamination. This paper synthesizes current research to elucidate the important role that fungus play in shaping the modern food industry and underscores the importance of ongoing scientific inquiry in harnessing their potential for sustainable and safe food production.

Design and Fabrication of Cost-Effective Composting for Easy Decomposing of Home Wastes

The primary objective is to develop a Household waste Decomposer that not only composting thee kitchen waste but also ensures quick decomposition while minimizing odors. Our design integrates innovative features, such as a compact and user-friendly composting unit, utilizing a controlled aeration system to accelerate the composting process. This aeration system promotes optimal conditions for microbial activity, enhancing the breakdown of organic matter Another one method added to using decomposer sand. Decomposition sand is a biological process that includes the physical breakdown and biochemical transformation of complex organic molecules of dead material into simpler organic and inorganic molecules. There are two effective system used in Household waste Decomposer. This composting process create a bad smell , so that we are using high suction power exhaust fan. In this suction fans is pull a Odorant particles throw out to the atmospheric air Food waste and decomposer sand ismixed well before pouring in top of the hopper. Food waste and decomposer mixer breakdown the particles like (leaf and tomato and other kitchen veg, waste food) using grinding method Traditional composting methods are slow decomposing and high level of odor form. Now odor free decomposer and quick decomposer at a same time cost effective home decomposing.Household waste Decomposer suitable for trace garden

Green energy breakthroughs: Harnessing nano-catalysts and enzymatic catalysts for bioenergy generation

Microbial fuel cells and anaerobic digestion are promising bioenergy methods but inefficient and scalable. With its exceptional surface area-to-volume ratio, nano-catalysts are revolutionizing this field. Researchers have improved energy conversion efficiency by immobilizing or embedding nanoparticles on electrodes or catalytic supports to promote electron transport. Nanomaterials like graphene-based catalysts and metal nanoparticles speed up organic matter breakdown and make bioenergy systems more profitable. Researchers are working harder to find new bioenergy-generating methods to address environmental concerns and the demand for sustainable energy. The study discusses how nano-catalysts and enzymatic catalysts are revolutionizing bioenergy production in green energy. Additionally, enzymatic catalysts are the best bioenergy catalysts. Highly specialized, biocompatible, and renewable enzymes provide unrivaled biofuel production potential. Protein engineering and immobilization have improved enzymes for bioenergy systems. Enzymatic catalysts enable biofuel generation from more feedstocks without harsh chemical procedures by controlling biological reactions quickly and precisely. Combining nano- and enzymatic catalysts is promising. Nano-catalysts improve enzymatic processes by creating a favorable microenvironment, enhancing surface binding sites, and enabling substrate transport. This combination may maximize bioenergy systems' biofuel output and wastewater treatment capabilities. According to this study, integrating nano- and enzymatic catalysts is a green energy breakthrough. These advances will improve bioenergy generation by overcoming current techniques, opening new sustainable energy production prospects, and expediting our transition to a greener, more sustainable future.

Intrinsic and extrinsic drivers of organic matter processing along phosphorus and salinity gradients in coastal wetlands

Abstract Climate change is accelerating sea‐level rise and saltwater intrusion in coastal regions world‐wide and interacting with large‐scale changes in species composition in coastal wetlands. Quantifying macrophyte litter breakdown along freshwater‐to‐marine coastal gradients is needed to predict how carbon stores will respond to shifts in both macrophyte communities and water chemistry under changing environmental conditions. To test the interactive drivers of changing species identity and water chemistry, we performed a reciprocal transplant of four macrophyte litter species in seven sites along freshwater‐to‐marine gradients in the Florida Coastal Everglades. We measured surface water chemistry (dissolved organic carbon, total nitrogen and total phosphorus), litter chemistry (% nitrogen, % phosphorus, change in N:P molar ratio, % cellulose and % lignin as proxies for recalcitrance) and litter breakdown rates (k/degree‐day). Direct effects of salinity and surface water nutrients were the strongest drivers of k, but unexpectedly, litter chemistry did not correlate with litter k. However, salinity strongly correlated with changes in litter chemistry, whereby litter incubated in brackish and marine wetlands was more labile and gained more phosphorus compared with litter in freshwater marshes. Our results suggest that litter k in coastal wetlands is explained by species‐specific interactions among water and litter chemistries. Water nutrient availability was an important predictor of breakdown rates across species, but breakdown rates were only explained by the carbon recalcitrance of litter in the species with the slowest breakdown (Cladium jamaicense), indicating the importance of carbon structure, and species identity on breakdown rates. Synthesis. In oligotrophic ecosystems, nutrients are often the primary driver of organic matter breakdown. However, we found that variation in macrophyte breakdown rates in oligotrophic coastal wetlands was also explained by salinity and associated seawater chemistry, emphasising the need to understand how saltwater intrusion will alter organic matter processing in wetlands. Our results suggest that marine subsidies associated with sea‐level rise have the potential to accelerate leaf litter breakdown. The increase in breakdown rates could either be buffered or increase further as sea‐level rise also shifts macrophyte community composition to more or less recalcitrant species.

System-scale dynamics of long-term sediment and phosphorus accumulation in contrasting valley-bottom wetlands in dryland landscapes of South Africa

Anthropogenic-induced acceleration of sediment and associated nutrients presents a serious challenge to water resource management across the globe. While wetlands are potential natural solutions, little is known of how well key wetland types attenuate downstream sediment fluxes and how these relate to local- and catchment-scale factors. This research aimed to develop an understanding of patterns and rates of sediment and phosphorus retention in valley-bottom wetlands in South Africa. The geomorphology, sedimentology and historical accretion rates of three wetlands which offered diversity in size, catchment position and degree of organic accumulation were compared to ascertain the impact of local- and catchment-scale factors. Estimates of sediment and associated phosphorus accumulation suggest higher rates in clastic sediment-dominated wetlands (1089–7655 g sediment m−2 yr−1, 0.4–1.6 g-P m−2 yr−1) compared to an organic sediment-dominated system (601–1308 g-sediment m−2 yr−1, 0.2–0.3 g-P m−2 yr−1). Sediment accretion rates generally increased longitudinally, indicating that distal wetland reaches act as sediment and phosphorus retention hotspots. Phosphorus distribution patterns were primarily attributed to variations in organic matter content and associated aluminium and iron complexing agents in fine-grained sediment deposits, while particle size distributions were less important. However, the relevance of individual complexing agents in phosphorus dynamics varied among wetlands with differing landscape conditions. Contrasts between these systems reflect variations in catchment lithology and hydroclimatic regime, which influence the relative magnitude of sediment supply and vegetation productivity. We postulate that intermediate-sized wetlands characterised by catchments around 900 ha in size, gentle longitudinal slopes (∼2 %), a high proportion of fine sediment deposition, limited organic matter breakdown, and a long vegetation growing season provide optimal conditions for sediment and phosphorus accumulation. This system-scale information is essential to guide management decisions to identify and prioritize within-catchment ‘hotspots’ of sediment and phosphorus retention.

Fractionation of stable carbon isotopes during formate consumption in anoxic rice paddy soils and lake sediments

Abstract. Formate is energetically equivalent to hydrogen and thus is an important intermediate during the breakdown of organic matter in anoxic rice paddy soils and lake sediments. Formate is a common substrate for methanogenesis, homoacetogenesis and sulfate reduction. However, how much these processes contribute to formate degradation and fractionate carbon stable isotopes is largely unknown. Therefore, we measured the conversion of formate to acetate, CH4 and CO2 and the δ13C of these compounds in samples of paddy soils from Vercelli, Italy, and the International Rice Research Institute (IRRI) in the Philippines and of sediments from the NE and SW basins of Lake Fuchskuhle, Germany. The samples were suspended in a phosphate buffer (pH 7.0) in both the absence and presence of sulfate (gypsum) and of methyl fluoride (CH3F), an inhibitor of aceticlastic methanogenesis. In the paddy soils, formate was mainly converted to acetate under both methanogenic and sulfidogenic conditions. Methane was only a minor product and was mainly formed from the acetate. In the lake sediments, the product spectrum was similar but only under methanogenic conditions. In the presence of sulfate, however, acetate and CH4 were only minor products. The isotopic enrichment factors (εform) of formate consumption, determined by Mariotti plots, were in the low range of −8 ‰ to −2.5 ‰ when sulfate was absent, and formate was mainly converted to acetate and CH4. However, no enrichment factor was detectable when formate was degraded with sulfate to mainly CO2. The δ13C of acetate was by about 25 ‰–50 ‰ more negative than that of formate, indicating acetate production by chemolithotrophic homoacetogenesis. Hence, formate seems to be an excellent substrate for homoacetogenesis in anoxic soils and sediments, so that this process is competing well with methanogenesis and sulfate reduction.

Deciphering the microbial functional potential of aeration drip irrigation to enhance soil organic carbon content

Aerated drip irrigation (ADI) is an important practice for promoting soil fertility and crop productivity in greenhouse vegetable production, yet little research has comprehensively investigated the effects on functional traits of carbon (C) cycling microorganisms. In this study, we sought to assess the potential efficacy of the ADI in enhancing soil organic carbon (SOC) content mediated via changes in microbial communities and the expression of genes associated with the carbon cycle. To this end, we adopted a metagenomics approach to compare the effects of ADI treatments with three dissolved oxygen concentrations (10, 15, and 20 mg L-1) during a three-season tomato cultivation experiment in northern China. The results revealed that the 10 mg L-1 treatment led to a significant increase in the abundance of KorA/B genes (associated with the rTCA cycle) in the C fixation pathway, whereas the 15 mg L-1 treatment increased the abundances of cbbL/R and coxL/S genes (associated with the Calvin cycle and carbon monoxide oxidation, respectively). In addition, based on a co-occurrence network analysis, we observed a positive correlation between cbbL and coxS. Interestingly, r-selected microorganisms, such as Proteobacteria and Actinomycetes, characterized by rapid cell multiplication and high biomass production, were identified as the primary contributors to C fixation and were the main predictors of SOC pools. In contrast, the 20 mg L-1 treatment was found to adversely influence C fixation, although enhanced C degradation could be attributed to the breakdown of organic matter by extracellular enzymes secreted by K-selected microorganisms. Collectively, our findings indicate that ADI with dissolved oxygen concentrations ≤15 mg L-1 can promote SOC content by altering the life history strategies of r-selected microorganisms and genes associated with C fixation. These findings will provide valuable insights into agroecosystem irrigation management, specifically in improving soil fertility and promoting sustainable production.

Skin Deep: The Potential of Microbiome Cosmetics.

The interplay between the skin microbiome and its host is a complex facet of dermatological health and has become a critical focus in the development of microbiome cosmetics. The skin microbiome, comprising various microorganisms, is essential from birth, develops over the lifespan, and performs vital roles in protecting our body against pathogens, training the immune system, and facilitating the breakdown of organic matter. Dysbiosis, an imbalance of these microorganisms, has been implicated in a number of skin conditions such as acne, atopic dermatitis, and skin cancer. Recent scientific findings have spurred cosmetic companies to develop products that preserve and enhance the skin's microbial diversity balance. These products may incorporate elements like prebiotics, probiotics, and postbiotics, which are beneficial for the skin microbiome. Beyond topical products, there's increasing interest in ingestible beauty supplements (i.e. oral probiotics), highlighting the connection between the gut and skin. This review examines the influence of the microbiome on skin health and the emerging trends of microbiome skincare products.