Decomposition Research Articles

Potential role of meiofauna in bioremediation: results from a microcosm experiment.

Meiofauna can act as remediation organisms by stimulating microphytobenthos, sequestering carbon dioxide, and degrading organic debris. Sediments from two basins in Lake Mariut, Egypt, which had undergone multiple rounds of restoration, were used in microcosm experiments to assess the role of meiofauna in organic matter degradation. Treatments included sediments with and without fauna, and four chlorophyll-a additions (0.002, 0.035, and 0.005 mg/ml, with 0.000 mg/ml as the reference). Meiofauna, chlorophyll-a, and organic matter were measured over two 8-month periods in 2014. Most treatments exhibited a rapid loss of organic matter, reducing organic content by two to eight times by study end. By the end, meiofaunal populations increased one- to 13-fold in microcosms with algae additions of 0.035 and 0.005 mg/ml chlorophyll-a in the Main and Northwest basins but had no change in those with 0.002 and zero mg/ml. Meiofauna abundance rose with rising temperature and oxygen levels, while organic matter declined. There was no correlation between chlorophyll-a levels and meiofauna abundance indicating that meiofauna likely play a role in the aerobic decomposition of organic matter at high temperatures. The meiofauna contribute to the diversity of ecosystems and have a potential role in ecosystem processes; therefore, conservation efforts should also include meiofauna.

Investigating the effects of bacterial decay rate on dilution and diffuser design

Investigating the effects of bacterial decay rate on dilution and diffuser design

Orbital pacing of the early Eocene source rock deposition in Tunisia (Bou Dabbous Formation): Astrobiochronological insights into cyclicities through surface-subsurface integration

The Early Eocene Bou Dabbous Formation (BDF) source rock is an economically important source rock in the SW Neo-Tethys covering most of the Ypresian outer ramp to basin deposits in Tunisia. The main rock types of the BDF in central Tunisia include globigerinids-rich grey to black laminated marl and limestone, which occur with an obvious cyclicity at astronomical timescales. This study examines two high-resolution borehole records from northern and eastern Tunisia and an outcrop analog in central Tunisia. The datasets examined were total organic carbon (TOC), magnetic susceptibility, CaCO3, δ13C, δ18O, and Gamma-Ray (GR). We aim to investigate the relationship between the rhythmic patterns observed at the BDF outcrop and the Milankovitch cycles and contextualize the findings within the Ypresian Astrochronological Time Scale (YATS). Additionally, we will discuss the impact of astronomical forcing on sea-level variations and the upwelling system during a greenhouse world. Field measurements and power spectra of the untuned data reveal a hierarchy of cycles throughout the BDF with ∼11.1 m, 4.1, 2.4 m, 1.1 m, and 0.6 m wavelengths. Tuning the 11.1 m cycles to the 405 kyr eccentricity cycle, the astronomical parameters—eccentricity, obliquity, and the precession index—become apparent. The 405 kyr eccentricity cycle is linked to relative sea-level changes inferred from sequence stratigraphy analysis and sedimentary noise modeling. Periods with increased TOC are associated with strong obliquity forcing inferred from the power decomposition analysis and the strong 173-kyr obliquity modulation cycles. The Ypresian record from Tunisia demonstrates the orbital pacing on the strength of the upwelling system, by affecting both the sea level and the climatic belt (wind regime). From 53.89 Ma to 53.2 Ma (TOC >2 wt %), our model demonstrates that obliquity-driven changes in water stratification led to episodes of varying oxygen levels at the bottom of the basin, affecting organic matter decay and preservation. During the Early Eocene Climatic Optimum, changes in climatic belts and wind patterns, along with rising sea levels, led to a shift in the high organic matter accumulation zone. This resulted in a weakened upwelling system in central Tunisia and reduced organic matter accumulation (TOC <0.5 wt%).

Climate Effects on Belowground Tea Litter Decomposition Depend on Ecosystem and Organic Matter Types in Global Wetlands.

Patchy global data on belowground litter decomposition dynamics limit our capacity to discern the drivers of carbon preservation and storage across inland and coastal wetlands. We performed a global, multiyear study in over 180 wetlands across 28 countries and 8 macroclimates using standardized litter as measures of "recalcitrant" (rooibos tea) and "labile" (green tea) organic matter (OM) decomposition. Freshwater wetlands and tidal marshes had the highest tea mass remaining, indicating a greater potential for carbon preservation in these ecosystems. Recalcitrant OM decomposition increased with elevated temperatures throughout the decay period, e.g., increase from 10 to 20 °C corresponded to a 1.46-fold increase in the recalcitrant OM decay rate constant. The effect of elevated temperature on labile OM breakdown was ecosystem-dependent, with tidally influenced wetlands showing limited effects of temperature compared with freshwater wetlands. Based on climatic projections, by 2050 wetland decay constants will increase by 1.8% for labile and 3.1% for recalcitrant OM. Our study highlights the potential for reduction in belowground OM in coastal and inland wetlands under increased warming, but the extent and direction of this effect at a large scale is dependent on ecosystem and OM characteristics. Understanding local versus global drivers is necessary to resolve ecosystem influences on carbon preservation in wetlands.

Study of temperature dynamics and influencing factors during composting process

Abstract This study investigated the most influential composting parameters (temperature, pH, humidity, C/N ratio, and CO2 emissions) on final compost quality. Composting bags (turned daily) containing prunings, lignocellulose material, cattle manure, and household organic waste were monitored for eight weeks across three batches. All the temperature data registered daily were statistically analyzed with one-way ANOVA to verify the consistency between batches. This study employs a first-order kinetic model to quantify the decomposition of organic matter in composting, revealing the influence of temperature on the decomposition rate. Principal component analysis was conducted for these factors and their interactions with respect to the final compost quality. Finished compost showed a significantly high nitrogen, phosphorus, and potassium content compared with that in the feedstock of the initial compost mixture, while there was constant organic carbon content. In addition to the control of key parameters, a linear regression analysis allowed us to identify the factors that most influenced temperature. We identified two key models: one including pH, humidity, C/N ratio, and CO2 emissions, and another focusing only on CO2. This study emphasized the importance of monitoring and controlling the crucial parameters of the composting process in order to obtain quality compost suitable for application in soil use. Moreover, high temperatures possibly attained in the process of aerobic decomposition destroy the pathogens, making the end products safer for uses in agriculture.

Determination and Optimization of Aerobic and Anaerobic Decomposition of Paper Sludge

The processing of paper sludge is currently an important environmental topic due to its high global production. The aim of this study is to monitor the biodegradation of paper sludge when the initial conditions change. Biodegradability tests 301F and OECD 311 were used to determine biodegradation. The data obtained from the tests were subsequently obtained for the simulation in MATLAB R2023b. The highest aerobic decomposition was approximately 80% after 28 days at an initial concentration of paper sludge leachate of 76 g/L. By simulating 3D modelling, we can predict that with a retention time of 1 day with degradation under aerobic conditions at the level of 70%, the ideal initial concentration of organic substances will be 157.55 g/L. Based on this model, it is possible to estimate that with a biogas production of 554 m3/tVS and a decomposition time of 20 days, it is necessary to set a concentration of approximately 128 g/L. Based on biodegradability tests, paper sludge was evaluated as suitable for aerobic or anaerobic biological decomposition.

Molecular basis for thermogenesis and volatile production in the titan arum.

The titan arum (Amorphophallus titanum), commonly known as the corpse flower, produces the largest unbranched inflorescence in the world. Its rare blooms last only a few days and are notable both for their burst of thermogenic activity and for the odor of rotting flesh by which they attract pollinators. Studies on the titan arum can therefor lend insight into the mechanisms underlying thermogenesis as well as the production of sulfur-based volatiles, about which little is known in plants. Here, we made use of transcriptome and metabolite analyses to uncover underlying mechanisms that enable thermogenesis and volatile production in the titan arum. The ability to perform thermogenesis correlated with the expression of genes involved in bypass steps for the mitochondrial electron transport chain, in particular alternative oxidase expression, and through our analysis is placed within the context of sugar transport and metabolism. The major odorants produced by the titan arum are dimethyl disulfide and dimethyl trisulfide, and we identified pathways for sulfur transport and metabolism that culminate in the production of methionine, which our analysis identifies as the amino acid substrate for production of these odorants. Putrescine, derived from arginine, was identified as an additional and previously unrecognized component of the titan arum's odor. Levels of free methionine and putrescine were rapidly depleted during thermogenesis, consistent with roles in production of the titan arum's odor. Models for how tissues of the titan arum contribute to thermogenesis and volatile production are proposed.

Characterization of the remaining material and mechanical properties of historic wooden foundation piles in Amsterdam

The majority of the bridges in the historic city centre of Amsterdam are supported by wooden foundation piles. Most of these were constructed 100–300 years ago, currently raising concerns about potential safety issues. The wooden piles under the bridges remain entirely under the water table, potentially subjected to bacterial decay in anaerobic conditions. Bacterial degradation proceeds at a slow rate, allowing the piles to perform their function for many years, although causing a reduction of their load-carrying capacity over time. To this end, a large experimental campaign was conducted to characterize the material and mechanical properties in relation to biological decay of 60 spruce and fir piles, dated back to 1727, 1886 and 1922, retrieved from two bridges in Amsterdam. Large-scale compression tests were carried out on 201 pile-segments extracted from head, middle-part and tip of the piles to determine their remaining short-term compressive strength. Micro-drilling measurements were conducted on each pile and analysed with a TU-Delft-developed algorithm, aimed at determining the soft shell – the width of the decayed outer layer of the piles’ cross section. Micro-drilling allowed to accurately assess the remaining sound cross section of the pile, which resulted to be well correlated to its mechanical properties. The extent of decay throughout the cross-section of the piles was assessed within sapwood and heartwood through experimental models from literature and validated with Computed Tomography (CT) scanning. This allowed to identify that bacterial decay was only present in the non-durable sapwood, even in very degraded piles. Moreover, the soft shell resulted to be rather uniform along the piles’ length. The analysis of decay, supported by micro-drilling and CT scans, allowed to develop experimental equations to predict the remaining short-term compressive strength along the pile length. The micro-drilling technique is now used on a large scale in Amsterdam, supporting the assessment of the remaining load carrying-capacity of wooden foundation piles in the city, aiding in the planning of conservation, maintenance and preservation strategies.

Effect of Vermicompost Supplement on Rainbow Trout Performance

Vermicompost is the product of organic waste digestion by earthworms besides aerobic decomposition at ambient temperature. It is a rich composition containing plant nutrients and beneficial microorganisms. Some fishes, especially predatory species such as rainbow trout, need nutritive feed so that they can be healthy; a useful and cheaper additive such as vermicompost can supply this aim. In this study, the effect of different percentages of vermicompost in the diet of rainbow trout was investigated. For this purpose, 100 rainbow trout with an average weight of 120±3 g were distributed in 5 groups in concrete tanks. Their nutrition and physical and chemical water parameters were determined according to the standard. Vermicompost with confirmable analysis was added to their daily feed (2, 4, 6, and 10%). After 2 months, the feed conversion ratio and survival rate were examined. The results showed that there was a significant relationship between the performance of the control group and the treatment groups (p

Nutrient-loaded seagrass litter experiences accelerated recalcitrant organic matter decay

High coastal nutrient loading can cause changes in seagrass chemistry traits that may lead to variability in seagrass litter decomposition processes. Such changes in decomposition have the potential to alter the carbon (C) sequestration capacity within seagrass meadows (‘blue carbon’). However, the external and internal factors that drive the variability in decomposition rates of the different organic matter (OM) types of seagrass are poorly understood, especially recalcitrant OM (i.e. cellulose-associated OM and lignin-associated OM), thereby limiting our ability to evaluate the C sequestration potential. It was conducted a laboratory incubation to compare differences in the decomposition of Halophila beccarii litter collected from seagrass meadows with contrasting nutrient loading histories. The exponential decay constants of seagrass litter mass, cellulose-associated OM and lignin-associated OM were 0.009–0.032, 0.014–0.054 and 0.009–0.033 d−1, respectively. The seagrass litter collected from meadows with high nutrient loading exhibited greater losses of mass (25.0–41.2 %), cellulose-associated OM (2.8–18.5 %) and lignin-associated OM (9.6–31.2 %) than litter from relatively low nutrient loading meadows. The initial and temporal changes of the litter nitrogen (N) and phosphorus (P) concentrations, stoichiometric ratios of lignin/N, C/N, and C/P, and cellulose-associated OM content, were strongly correlated with the losses of litter mass and different types of OM. Further, temporal changes of litter C and OM types, particularly the OM and labile OM concentrations, were identified as the main driving factors for the loss of litter mass and loss of different OM types. These results indicated that nutrient-loaded seagrass litter, characterized by elevated nutrient levels and diminished amounts of recalcitrant OM, exhibits an accelerated decay rate for the recalcitrant OM. These differences in litter quality would lead to a reduced contribution of seagrass litter to long-term C stocks in eutrophic meadows, thereby weakening the stability of C sequestration. Considering the expected changes in seagrass litter chemistry traits and decay rates due to long-term nutrient loading, this study provides useful information for improving C sequestration capabilities through effective pollution management.

Rewetting on agricultural peatlands can offer cost effective greenhouse gas reduction at the national level

To reach EU’s carbon neutrality target by 2050, emission reductions in the land-use sector are needed. Agricultural peatlands attribute for half of the greenhouse gas emissions of cropland in both in EU and Finland. High greenhouse gas emissions from agricultural peatlands are primarily caused by CO2 emissions following aerobic peat decomposition due to deep drainage, and studies have shown that raising water-table has potential to slow down the decomposition process. Here we studied the emission reduction potential and cost of implementing controlled drainage, paludiculture, peatland restoration and afforestation to current land use on agricultural peatlands in Finland. We created three scenarios with increasing amount of wet field use on cultivated organic soils and estimated their effects on national greenhouse gas emissions and farmers’ income. The yearly emission reduction ranged from 0.3 to 5.0 Mt CO2 equivalents in the different scenarios compared to the current state in Finland. Emission reductive land use had a negative impact on the farmers income, which should be compensated. Assuming the government compensates the lost income for the farmers, the cost of emission reduction ranged from −4 to 45 € per ton of CO2 equivalents. Rewetting provided the most emission reduction per area and was the most cost effective. We conclude that substantial emission reduction is attainable by rewetting agricultural peatlands. The cost of emission reduction is inexpensive compared to average carbon price in European Union emission trading system, or to the costs of technical carbon capture and storage in Finland.

Innovative application of micro-drilling for the assessment of decay and remaining mechanical properties of historic wooden foundation piles in Amsterdam

The majority of bridges and quay walls in the centre of Amsterdam are supported by 100–300 years-old wooden foundation piles subjected to bacterial decay. Bacterial degradation proceeds at a slow rate, allowing the piles to perform their function for many years, although causing a reduction of their load-carrying capacity over time. In this study, micro-drilling measurements were employed to capture the amount of decay and remaining short-term compressive strength of the historic wooden piles. The applicability of micro-drilling was studied on 60 wooden piles with various decay levels, retrieved after 100–295 years of service life. An algorithm was developed for analysing the micro-drilling signals, aimed at determining the decayed outer layer of the piles’ cross section, and validated with the results of mechanical testing on the piles. The micro-drilling technique is now used on a large scale in Amsterdam, supporting the assessment of the wooden foundation piles in the city.

Organic matter decay and bacterial community succession in mangroves under simulated climate change scenarios.

Mangroves are coastal environments that provide resources for adjacent ecosystems due to their high productivity, organic matter decomposition, and carbon cycling by microbial communities in sediments. Since the industrial revolution, the increase of Greenhouse Gases (GHG) released due to fossil fuel burning led to many environmental abnormalities such as an increase in average temperature and ocean acidification. Based on the hypothesis that climate change modifies the microbial diversity associated with decaying organic matter in mangrove sediments, this study aimed to evaluate the microbial diversity under simulated climate change conditions during the litter decomposition process and the emission of GHG. Thus, microcosms containing organic matter from the three main plant species found in mangroves throughout the State of São Paulo, Brazil (Rhizophora mangle, Laguncularia racemosa, and Avicennia schaueriana) were incubated simulating climate changes (increase in temperature and pH). The decay rate was higher in the first seven days of incubation, but the differences between the simulated treatments were minor. GHG fluxes were higher in the first ten days and higher in samples under increased temperature. The variation in time resulted in substantial impacts on α-diversity and community composition, initially with a greater abundance of Gammaproteobacteria for all plant species despite the climate conditions variations. The PCoA analysis reveals the chronological sequence in β-diversity, indicating the increase of Deltaproteobacteria at the end of the process. The GHG emission varied in function of the organic matter source with an increase due to the elevated temperature, concurrent with the rise in the Deltaproteobacteria population. Thus, these results indicate that under the expected climate change scenario for the end of the century, the decomposition rate and GHG emissions will be potentially higher, leading to a harmful feedback loop of GHG production. This process can happen independently of an impact on the bacterial community structure due to these changes.

Study of an auxiliary trimming device for cracked carrots

AbstractCracked carrots account for a large proportion of defective carrots, which are usually discarded or used as feed, resulting in resource waste and economic benefit loss. Cracked carrots can be used as raw materials for further processed carrot products after being trimmed. So, an auxiliary device was developed combining PLC (Programmable Logic Controller) and machine vision to achieve clamping and crack defect localization for intelligent trimming of crack defect. The carrot was orientated based on the area method, rotated by flexible jaws and a rotating cylinder to make the carrot head and tail aligned. The clamping device could non‐destructively clamp carrot in axial and radial direction with a force threshold of 10 and 22 N respectively, and rotate carrot to make the crack defect upwards. The results showed that the recognition accuracy of carrot head and tail orientation was 98%, the average deviation of carrot centroid clamping position was less than 9 mm at a speed of 300 mm/s, the rotational positioning time was less than 3 s and the number of adjustments were no more than 2 at a motor speed of 180 rpm, which could meet the subsequent trimming requirements.Practical applicationsTrimming the cracked area of carrots can reduce bacterial growth and decay, which is beneficial for subsequent processing and reduces resource waste. This article designs a carrot auxiliary trimming device, which uses image processing technology to recognize the orientation of the head and tail of carrots and the cracked area, and uses automated equipment to achieve stable clamping of carrots and make the cracked area face the trimming tool. This study is beneficial for the refined management of agricultural products.

Kinetic of Aerobic Decomposition Process of Linear Alkylbenzene Sulfonate (LAS) in a Well-Shaped Bioreactor Using Commercial Inoculum

Linear alkylbenzene sulfonate (LAS) belongs to a class of surfactants claimed as an environmentally friendly detergent due to its biodegradability. However, the disposal of LAS waste into the waters without prior treatment causes a risk to the ecosystem. These experiments aimed to study the effects of commercial inoculum size EM-4 on the aerobic decomposition process of LAS in a well-shaped bioreactor. These experiments of LAS decomposition were carried out in a batch system aerated by 2.5 L/min for the low and high initial LAS concentrations. The effects of inoculum acclimation were also investigated for the high LAS concentration. The effects of inoculum size were explored at sizes ranging from 5 to 20% v/v, and samples were taken on a regular basis for residual LAS assessment. The first-order kinetic model gave the best fit to the rate of LAS decomposition, with the highest rate coefficient of 10.44 x 10-2 hour-1. This was achieved by using a 20% v/v inoculum for the initial low concentration of LAS, resulting in the highest decomposition efficiency of 89.4% after 24 hours of incubation. The decomposition rate was slower at the high LAS concentrations than at the low concentrations. The inoculum acclimation increased the decomposition rate for the high LAS concentrations. The results of this study show great potential for the bioremediation of LAS detergent waste using commercial inoculum in a well-shaped batch bioreactor.

Classical Study of Real Life Applications of Exponential Function

One of the most prevalent applications of exponential function involves growth and decay modes. Exponential growth and decay show up in a host of applications. From population growth and continuously compounded interest to radioactive decay and Newton’s law of cooling exponential function are ubiquities in nature. In this section, we examine exponential growth and decay in the context of some of the application. In the preceding section, we examined a population growth problem in which the population grew at a fixed percentage each year. In that case, we found that the populations can be described by an exponential function. A similar analysis will show that any process in which a quality grows by a fixed percentage each year (or each day, hours, etc) can be modeled by an exponential function. Compound interest is a good example of such a process. Other applications of exponential function are bacterial growth, bacterial decay, population decline are obtained in this project (see [1-27])

Aerobic and anaerobic decomposition rates in drained peatlands: Impact of botanical composition

Drained peatlands in temperate climates are under threat from climate change and human activities. The resulting decomposition of organic matter plays a major role in regulating the associated land subsidence rates, yet the determinants of aerobic and anaerobic peat decomposition rates are not fully understood. In this study, we sought to gain insight into the drivers of decomposition rates in botanically diverse peatlands (sedge, reed, wood, and moss dominant) under oxic and anoxic conditions. Peat samples were collected from the anoxic zone and incubated for 24 h (short) and 15 weeks (long) under either oxic or anoxic conditions. CO2 emissions, hydrolytic and oxidative exoenzyme potential activities, phenolic compound concentrations, and several edaphic factors were measured at the end of each incubation period.We found that 15 weeks of oxygen exposure of anoxic peat samples accelerated the average CO2 emissions by 3.9-fold. Reed and sedge peat respired more than wood and moss peat under anoxic conditions. Interestingly, CO2 emissions from anoxic peat layers under permanently anoxic conditions were substantial and given the thickness of peat deposits in the field, such activities may play an important role in long-term land subsidence rates and total CO2 emissions from drained peatlands. The results from the long-term incubations showed that decomposition rates appear to be also controlled by factors other than oxygen intrusion such as substrate availability. In summary, the botanical composition of the peat matrix, incubation conditions and time of incubation are all important factors that need to be considered when predicting peat decomposition and subsequent land subsidence rates.

Developing a numerical model for microbial methanation in a depleted hydrocarbon reservoir

Biological methanation is a promising option for CO2 utilization and energy storage. While the underground condition is not appropriate for a methanation reaction, microorganisms act as a catalyst and make the reaction possible. This study investigates the performance of biological methanation in depleted gas reservoirs using numerical simulation. To do this, a one-dimensional synthetic homogeneous depleted gas reservoir is modeled with the two-phase flow comprising components H2, CO2, CH4, and H2O. Then, the simultaneous injection of CO2 and H2 into the reservoir is numerically simulated to evaluate the methane production rate in MATLAB Reservoir Simulation Toolbox (MRST) open-source software. Long-term results show propagating composition waves and pressure profiles. Sensitivity analysis reveals that methane production is positively correlated with the initial reservoir pressure and the number of methanogenic microorganisms, but negatively correlated with the temperature and the bacterial decay rate. The bacterial growth rate has an insignificant effect on methane production in this model. The bacterial population is the most critical parameter, as 1e7 methanogenic microorganisms per cubic meter of aqueous phase can produce 96% pure methane after 12 years. Overall, the work demonstrates harnessing in-situ bio-reactions to utilize CO2 and recover depleted gas reservoirs.

Investigating the sources and fate of per- and polyfluoroalkyl substances (PFAS) in food waste compost

Composting municipal food waste is a key strategy for beneficially reusing methane-producing waste that would otherwise occupy landfill space. However, land-applied compost can cycle per- and polyfluoroalkyl substances (PFAS) back into the food supply and the environment. We partnered with a pilot-scale windrow composting facility to investigate the sources and fate of 40 PFAS in food waste compost. A comparison of feedstock materials yielded concentrations of ∑PFAS under 1 ng g−1 in mulch and food waste and at 1380 ng g−1 in leachate from used compostable food contact materials. Concentrations of targeted ∑PFAS increased with compost maturity along the windrow (1.85–23.1 ng g−1) and in mature stockpiles of increasing curing age (12.6–84.3 ng g−1). Among 15 PFAS quantified in compost, short-chain perfluorocarboxylic acids (PFCAs) – C5 and C6 PFCAs in particular – led the increasing trend, suggesting biotransformation of precursor PFAS into these terminal PFAS through aerobic decomposition. Several precursor PFAS were also measured, including fluorotelomer carboxylic acids (FTCAs) and polyfluorinated phosphate diesters (PAPs). However, since most targeted analytical methods and proposed regulations prioritize terminal PFAS, testing fully matured compost would provide the most relevant snapshot of PFAS that could be land applied. In addition, removing co-disposed food contact materials from the FW feedstock onsite yielded only a 37 % reduction of PFAS loads in subsequent compost, likely due to PFAS leaching during co-disposal. Source-separation of food contact materials is currently the best management practice for meaningful reduction of PFAS in food waste composts intended for land application.

Integrating Tide‐Driven Wetland Soil Redox and Biogeochemical Interactions Into a Land Surface Model

AbstractRedox processes, aqueous and solid‐phase chemistry, and pH dynamics are key drivers of subsurface biogeochemical cycling and methanogenesis in terrestrial and wetland ecosystems but are typically not included in terrestrial carbon cycle models. These omissions may introduce errors when simulating systems where redox interactions and pH fluctuations are important, such as wetlands where saturation of soils can produce anoxic conditions and coastal systems where sulfate inputs from seawater can influence biogeochemistry. Integrating cycling of redox‐sensitive elements could therefore allow models to better represent key elements of carbon cycling and greenhouse gas production. We describe a model framework that couples the Energy Exascale Earth System Model (E3SM) Land Model (ELM) with PFLOTRAN biogeochemistry, allowing geochemical processes and redox interactions to be integrated with land surface model simulations. We implemented a reaction network including aerobic decomposition, fermentation, sulfate reduction, sulfide oxidation, methanogenesis, and methanotrophy as well as pH dynamics along with iron oxide and iron sulfide mineral precipitation and dissolution. We simulated biogeochemical cycling in tidal wetlands subject to either saltwater or freshwater inputs driven by tidal hydrological dynamics. In simulations with saltwater tidal inputs, sulfate reduction led to accumulation of sulfide, higher dissolved inorganic carbon concentrations, lower dissolved organic carbon concentrations, and lower methane emissions than simulations with freshwater tidal inputs. Model simulations compared well with measured porewater concentrations and surface gas emissions from coastal wetlands in the Northeastern United States. These results demonstrate how simulating geochemical reaction networks can improve land surface model simulations of subsurface biogeochemistry and carbon cycling.