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Weathering indices are quantitative models that relate the soil's geochemical characteristics to its weathering state. Wetland soils derived from basement complexes and sedimentary rocks were studied to determine their elemental composition and degree of weathering for soil fertility management. Three profile pits were dug in each formation and described using the FAO guidelines. Soil samples were collected from genetic horizons and analyzed for major elements (Si, Fe, Al, Ti, Ca, Mg, Na, K, Mn, and P) using appropriate methods. The weathering degree was characterized using eleven indices (SCR, SSR, V, WIP, CIA, CIW, CPA, MIA, PWI, PIA, and IOL). Results showed that the wetlands had a loamy sand texture at the surface, while the subsurface horizons had sandy loam and sandy clay texture. Soil pH ranged from strongly acidic to neutral (4.1–7.6). Ca and Mg dominated the exchange sites. Geochemically, Na2O, K2O, CaO, MgO, MnO, and P2O5 contents decreased while SiO2, Al2O3, Fe2O3, and TiO2 tend to accumulate in both formations. The indices values were in the ranges: SCR 0.21–0.67; SSR 2.21–15.69; V 0.85–1.75; WIP 602.10–1388.11; CIA 51.31–69.32; CIW 54.00–71.28; CPA 88.26–95.97; MIA 2.16–38.64; PWI 68.85–86.60; PIA 51.45–70.45, and IOL 12.90–30.35. Pearson coefficients and principal component analysis (PCA) of the oxides and the indices showed a highly significant (p <.05) correlation. Based on weathering indices, the soils in both formations showed a moderate degree of weathering. With the levels of OC and CEC, the soils were moderately fertile and could sustain crops grown on them with or without inputs. [ABSTRACT FROM AUTHOR]

Microplastic (MP) pollution, an emerging global change factor, disturbs the ecosystem functioning. Inland wetlands, providing important ecosystem services, might be an important sink for MPs. Understanding the distribution, source, and fate of MPs in inland wetland ecosystems is a prerequisite for developing an effective management strategy. Here, different types of inland wetlands, including the river wetland, constructed wetland, and lake wetland, were selected to explore the pollution patterns of MPs therein. Results showed that the abundance of MPs in wetland soil ranges from 532 to 4309 items/kg. Transparent, fibers, and polyethylene terephthalate were the most common color, shape, and polymer type of MPs, respectively. The constructed wetland in this study did not significantly remove MPs. The lake wetland was one of the main sinks for MPs in the inland wetland ecosystem and had accumulated large amounts of MPs. In addition, MP characteristics and cluster analyses showed that aquaculture, agricultural cultivation, and domestic waste were the most important sources of MPs in the study area. The occluded particulate organic carbon content in this study was related to MP abundance. In conclusion, this study reveals the pollution characteristics of MPs in the special inland wetland ecosystem of river-constructed-lake wetlands, which would help to better understand the distribution and source of MPs in inland wetlands and have implications for the subsequent pollution control and ecological restoration of inland wetlands. [ABSTRACT FROM AUTHOR]

This study examines the responses of soil organic carbon (SOC) pools and their components to agricultural water drainage in paddy fields, with a focus on the wetland–paddy field ecotone of Xingkai Lake, a transboundary lake shared by China and Russia. Field investigations targeted three representative wetland vegetation types: Glyceria spiculosa (G), Phragmites australis (P), and Typha orientalis (T), across drainage durations ranging from 0 to over 50 years. SOC fractions, including light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC), were systematically analyzed. The results revealed that SOC components in T and P wetlands steadily increased with drainage duration, whereas those in G wetlands exhibited a fluctuating pattern. SOC dynamics were primarily driven by LFOC, while MBC displayed species-specific variations. Correlation analyses and structural equation modeling (SEM) demonstrated that soil physicochemical properties, such as total nitrogen and moisture content, exerted a stronger influence on SOC fractions than microbial biomass. Overall, water drawdown significantly altered SOC dynamics, with distinct responses observed across vegetation types and wetland ages. This study provides critical data and theoretical insights for optimizing carbon sequestration and hydrological management in wetland–paddy field systems. [ABSTRACT FROM AUTHOR]

Coastal wetlands, including freshwater systems near large lakes, rapidly bury carbon, but less is known about how they transport carbon either to marine and lake environments or to the atmosphere as greenhouse gases (GHGs) such as carbon dioxide and methane. This study examines how GHG production and organic matter (OM) mobility in coastal wetland soils vary with the availability of oxygen and other terminal electron acceptors. We also evaluated how OM and redox-sensitive species varied across different size fractions: particulates (0.45–1μm), fine colloids (0.1–0.45μm), and nano particulates plus truly soluble (<0.1μm; NP+S) during 21-day aerobic and anaerobic slurry incubations. Soils were collected from the center of a freshwater coastal wetland (FW-C) in Lake Erie, the upland-wetland edge of the same wetland (FW-E), and the center of a saline coastal wetland (SW-C) in the Pacific Northwest, USA. Anaerobic methane production for FW-E soils were 47 and 27,537 times greater than FW-C and SW-C soils, respectively. High Fe2+ and dissolved sulfate concentrations in FW-C and SW-C soils suggest that iron and/or sulfate reduction inhibited methanogenesis. Aerobic CO2 production was highest for both freshwater soils, which had a higher proportion of OM in the NP+S fraction (64±28% and 70±10% for FW-C and FW-E, respectively) and organic C:N ratios reflective of microbial detritus (5.3±5.3 and 5.3±7.0 for FW-E and FW-C, respectively) compared to SW-C, which had a higher fraction of particulate (58±9%) and fine colloidal (19±7%) OM and organic C:N ratios reflective of vegetation detritus (11.4 ± 1.7). The variability in GHG production and shifts in OM size fractionation and composition observed across freshwater and saline soils collected within individual and across different sites reinforce the high spatial variability in the processes controlling OM stability, mobility, and bioavailability in coastal wetland soils. [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) transformation is an essential portion of the N cycle in wetland ecosystems, governing the retention status of soil N by controlling the effective soil N content. N deposition produced by human activities changes the physical characteristics of soil, affecting N fractions and enzyme activities. To characterize these influences, three different N addition levels (N5, 5 g/m2; N10, 10 g/m2; N15, 15 g/m2) were established using a wet meadow on the Qinghai-Tibet Plateau (QTP) as a control treatment (0 g/m2). We investigated the features of soil physical property alterations, N fractions contents, and enzyme activities under N addition conditions throughout the peak plant growth season. Our findings indicated that N addition significantly enhanced soil aeration, porosity, total nitrogen (TN), ammonium nitrogen (NH4+), nitrate nitrogen (NO3−) content, and urease activity. At the same time, it decreased soil dissolved organic nitrogen (DON) content and bulk density (BD). Additionally, N addition treatment exerted a significant seasonal impact on soil nitrogen component content. The nitrogen component content within the surface soil (0–10 cm) under four treatments is more sensitive to N addition, whereas the nitrogen component in the deep soil is relatively stable. Principal component analysis demonstrated that soil aeration and porosity were the primary factors affecting soil N fractions and enzyme activities. The findings suggested that lower levels of N addition promoted the transformation process of soil N pools in wet meadows and exacerbated the loss of N in wetland ecosystems. Our findings indicate that sustained increases in N deposition will accelerate soil microbial N cycling, potentially overcoming N limitation in alpine wetland ecosystems and exacerbating the risk of N loss and greenhouse gas emissions from alpine wetland surface soils. [ABSTRACT FROM AUTHOR]

Soil salinization refers to the accumulation of water‐soluble salts in the upper part of the soil profile. Excessive levels of soil salinity affects crop production, soil health, and ecosystem functioning. This phenomenon threatens agriculture, food security, soil stability, and fertility leading to land degradation and loss of essential soil ecosystem services that are fundamental to sustaining life. In this review, we synthesize recent advances in soil salinization at various spatial and temporal scales, ranging from global to core, pore, and molecular scales, offering new insights and presenting our perspective on potential future research directions to address key challenges and open questions related to soil salinization. Globally, we identify significant challenges in understanding soil salinity, which are (a) the considerable uncertainty in estimating the total area of salt‐affected soils, (b) geographical bias in ground‐based measurements of soil salinity, and (c) lack of information and data detailing secondary salinization processes, both in dry‐ and wetlands, particularly concerning responses to climate change. At the core scale, the impact of salt precipitation with evolving porous structure on the evaporative fluxes from porous media is not fully understood. This knowledge is crucial for accurately predicting soil water loss due to evaporation. Additionally, the effects of transport properties of porous media, such as mixed wettability conditions, on the saline water evaporation and the resulting salt precipitation patterns remain unclear. Furthermore, effective continuum equations must be developed to accurately represent experimental data and pore‐scale numerical simulations. Plain Language Summary: Soil salinization refers to the excess accumulation of salt in soil to a level that affects crop production and ecosystem functioning. This poses existential threat to sustainable agriculture, food security, and soil fertility. Soil salinization is considered as one of the major drivers for desertification, resulting in a persistent loss of ecosystem services. It also imposes nutritious imbalances in plants that may induce significant alterations in Earth's organisms, ecosystems, and biodiversity. We synthesized recent advances on soil salinization at different length and time scales, ranging from pore to global scale, offering new insights, and presenting future perspective on the key challenges and open questions on soil salinization. Key Points: Soil salinization poses existential threat to sustainable agriculture, food security, and soil fertilityWe synthesized recent advances on soil salinization at different length scales, ranging from pore to global scaleWe offer new insights and present future outlook on the key challenges and open questions related to soil salinization [ABSTRACT FROM AUTHOR]

This experiment was performed to determine the phosphorus levels in certain wetland soils in Edo State, Nigeria. Soil samples were collected from five wetlands at two depths: 0-15 cm and 15-30 cm. The samples were air-dried, sieved, and analyzed to ascertain the physical and chemical properties of the soils using standard laboratory techniques. The findings indicated that the majority of soil pH levels were slightly acidic, ranging from 6.6 to 7.0 (neutral), with the exception of soils from Obiemen, Agwa, and Benin, which exhibited moderate acidity (4.2-4.8). Soils from Irrua (Obiemen and Agwa) and Benin (Ikpoba Okha) demonstrated elevated phosphorus content, with a P range of 11.41-15.70 mg/kg, whereas soils from Ekpoma (Opoji), Benin (Oka-Naruovia), and Benin (Orhiomwon) exhibited low phosphorus levels, ranging from 2.88 to 5.56 mg/kg. There was a direct relationship between soil pH and the available phosphorus content. Therefore, there is need to augment the soils with P-fertilizers for increase crop productivity. [ABSTRACT FROM AUTHOR]

Poyang Lake is the largest freshwater lake in China, which boasts unique hydrological conditions and rich biodiversity. In this study, metagenomics technology was used to sequence the microbial genome of soil samples S1 (sedimentary), S2 (semi-submerged), and S3 (arid) with different water content from the Poyang Lake wetland; the results indicate that the three samples have different physicochemical characteristics and their microbial community structure and functional gene distribution are also different, resulting in separate ecological functions. The abundance of typical ANME archaea Candidatus Menthanoperedens and the high abundance of mcrA in S1 mutually demonstrate prominent roles in the methane anaerobic oxidation pathway during the methane cycle. In S2, the advantageous bacterial genus Nitrospira with ammonia oxidation function is validated by a large number of nitrification functional genes (amoA, hao, nxrA), manifesting in that it plays a monumental role in nitrification in the nitrogen cycle. In S3, the dominant bacterial genus Nocardioides confirms a multitude of antibiotic resistance genes, indicating their crucial role in resistance and their emphatic research value for microbial resistance issues. The results above have preliminarily proved the role of soil microbial communities as indicators predicting wetland ecological functions, which will help to better develop plans for restoring ecological balance and addressing climate change. [ABSTRACT FROM AUTHOR]

This study examines CH4 and N2O fluxes during the dry season in two distinct areas of the Pantanal: Barranco Alto Farm (BAF), dominated by grasslands, and Passo da Lontra (PL), a forested region. As climate change increases the occurrence of droughts, understanding greenhouse gas (GHG) fluxes in tropical wetlands during dry periods is crucial. Using static chambers, CH4 and N2O emissions were measured from soils and tree stems in both regions, with additional measurements from grass in BAF. Contrary to expectations, PL—characterized by clayey soils—had sandy mud samples that retained less water, promoting oxic conditions and methane uptake, making it a CH4 sink. Meanwhile, BAF's sandy, well-drained soils exhibited minimal CH4 fluxes, with negligible methane uptake or emissions. N2O fluxes were generally higher in BAF, particularly from tree stems, indicating significant interactions between soil type, moisture, and vegetation. These findings highlight the pivotal roles of soil texture and aeration in GHG emissions, suggesting that well-drained, sandy soils in tropical wetlands may not always enhance methane oxidation. This underscores the importance of continuous GHG monitoring in the Pantanal to refine climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

To explore the role of different forms of N input on the process of organic N mineralization in rhizosphere soil of wetland plants, the rate of N mineralization was measured using the continuous flooding incubation method with the reeds and in-situ soils of Dezhou Jianhe wetland which was collected in August 2021. The results showed that there was different effect on the release of root exudates among different N treatment, where the addition of NH4-Cl and urea had the most obvious effect on the increase of amino acids, flavonoids, total phenols and total sugars contents in rhizosphere roots(P<0.01), but had no significant effect on the secretion of total acids. Nitrogen addition had a significant effect on urease activity (P<0.01), and the urease activity ranged from 88.90 to 500.00 μg·g-1·d-1, but had no significant effect on protease activity. The mineralization rate of soil N ranged from 5.79 to 21.12 mg·kg–1·d–1, which showed a significant positive correlation with urease (P<0.05), indicating that urease could play an important role in regulating the mineralization process. The activities of urease in the rhizosphere soil were significantly and positively correlated with the content of TOC and TN (P<0.01). The high TOC content provided energy for microbial metabolism and promoted the increase of microbial metabolites. TN could significantly induce the production of urease. Except for total acids, all root exudates showed significant positive correlations (P<0.05) with MBN, MBC and urease activities. The exogenous N input mainly promotes the mineralization process of organic N by stimulating the release of plant root exudates, changing the microenvironment of the soil around the roots, and provides the substrate and energy for mineralized microorganisms. Therefore, it is necessary to strengthen the protection and restoration of wetland plants and improve the ecological service function of wetland in the process of wetland management. [ABSTRACT FROM AUTHOR]

Elucidating the dynamics of soil microbial diversity in coastal wetlands is essential for understanding the changes in ecological functions within these ecosystems, particularly in the context of climate change and improper management practices. In this study, the diversity patterns and influencing factors of soil bacterial and fungal communities in a muddy coastal wetland in China were investigated using Illumina sequencing of 16S rRNA and ITS1, across wetlands dominated by different vegetations and varying proximity to the coastline. The wetlands include four plots dominated by Spartina alterniflora (SA1), four plots dominated by Suaeda glauca (SG2), additional four plots of Suaeda glauca (SG3), and four plots dominated by Phragmites australis (PA4), ranging from the nearest to the coast to those farther away. The results revealed significant differences in bacterial richness (Observed_species index) and fungal diversity (Shannon index) across different wetlands, with SG3 demonstrating the lowest bacterial Observed_species value (1430.05), while SA1 exhibited the highest fungal Shannon value (5.55) and PA4 showing the lowest fungal Shannon value (3.10). Soil bacterial and fungal community structures differed significantly across different wetlands. The contents of soil available phosphorus and total phosphorus were the main drivers for fungal Observed_species and Shannon index, respectively. Soil organic carbon, pH, and salinity were indicated as the best predictors of bacterial community structure, accounting for 28.1% of the total variation. The total nitrogen content and soil salinity contributed mostly to regulating fungal community structure across different wetlands, accounting for 19.4% of the total variation. The results of this study offer a thorough understanding of the response and variability in soil microbial diversity across the muddy coastal wetlands in China. [ABSTRACT FROM AUTHOR]

Leaf litter in coastal wetlands lays the foundation for carbon storage, and the creation of coastal wetland soils. As climate change alters the biogeochemical conditions and macrophyte composition of coastal wetlands, a better understanding of the interactions between microbial communities, changing chemistry, and leaf litter is required to understand the dynamics of coastal litter breakdown in changing wetlands. Coastal wetlands are dynamic systems with shifting biogeochemical conditions, with both tidal and seasonal redox fluctuations, and marine subsidies to inland habitats. Here, we investigated gene expression associated with various microbial redox pathways to understand how changing conditions are affecting the benthic microbial communities responsible for litter breakdown in coastal wetlands. We performed a reciprocal transplant of leaf litter from four distinct plant species along freshwater‐to‐marine gradients in the Florida Coastal Everglades, tracking changes in environmental and litter biogeochemistry, as well as benthic microbial gene expression associated with varying redox conditions, carbon degradation, and phosphorus acquisition. Early litter breakdown varied primarily by species, with highest breakdown in coastal species, regardless of the site they were at during breakdown, while microbial gene expression showed a strong seasonal relationship between sulfate cycling and salinity, and was not correlated with breakdown rates. The effect of salinity is likely a combination of direct effects, and indirect effects from associated marine subsidies. We found a positive correlation between sulfate uptake and salinity during January with higher freshwater inputs to coastal areas. However, we found a peak of dissimilatory sulfate reduction at intermediate salinity during April when freshwater inputs to coastal sites are lower. The combination of these two results suggests that sulfate acquisition is limiting to microbes when freshwater inputs are high, but that when marine influence increases and sulfate becomes more available, dissimilatory sulfate reduction becomes a key microbial process. As marine influence in coastal wetlands increases with climate change, our study suggests that sulfate dynamics will become increasingly important to microbial communities colonizing decomposing leaf litter. [ABSTRACT FROM AUTHOR]

As important carbon sinks, alpine wetlands on the Tibetan Plateau are undergoing severe degradation. To reveal warming-induced ecological shifts in alpine environments, this study determined soil nutrient contents, enzyme activities, absorption and fluorescence spectra and quadrupole time-of-flight mass spectra (metabolomes) of dissolved organic matter (DOM) and metagenomes based on short-term incubation (0 °C, 10 °C and 20 °C) of topsoil from alpine wetlands and meadows (degraded wetlands). Compared with meadows, wetlands had higher contents of soil DOM (dissolved organic carbon, dissolved organic nitrogen and dissolved phosphorous) and greater activities of hydrolases (β-glucosidase, cellobiohydrolase, β-N-acetylglucosaminidase and acid phosphatase), with those parameters all being highest at 20 °C in meadows and showing various dynamics in wetlands. Soil DOM in wetlands presented the lowest values of specific ultraviolet absorbances (SUVA254 and SUVA260) at 0 °C and the highest values at 10 °C, whereas the opposite was true in the meadows. Wetland soils had greater diversities of DOM molecular compositions and microbial communities, with warming gradually increasing the number of identified DOM compounds in meadows and decreasing the number of microbial species in both soils. Wetland soils had more Proteobacteria (44.2%) and Acidobacteria (21.1%) and fewer Actinobacteria (18.0%) than meadow soils and contained many temperature-sensitive archaea (which were abundant at 0 °C). Distance-based redundancy analysis and Procrustes analysis indicated the greater complexity of ecological responses in alpine wetlands, which may be attributed to the higher adaptive capacity of soil microbial communities. Our results suggest that both degradation and warming decrease soil DOM content and microbial activities in alpine wetlands, providing important references for alpine wetland conservation under current climate change. [ABSTRACT FROM AUTHOR]

To meet the demands of a growing population, natural wetlands are being converted to arable land, significantly impacting soil biodiversity. This study investigated the effects of land use changes on bacterial communities in wetland, arable land, and forest soils in the Lesser Khingan Mountains using Illumina MiSeq 16S rRNA sequencing. Soil physicochemical properties and enzyme activities were measured using standard methods, while microbial diversity was assessed through sequencing analysis. Our findings revealed that forest soils had significantly higher levels of total potassium (2.62 g·kg−1), electrical conductivity (8.22 mS·cm−1), urease (0.18 mg·g−1·d−1), and nitrate reductase (0.13 mg·g−1·d−1), attributed to rich organic matter and active microbial communities. Conversely, arable soils showed lower total potassium (1.94 g·kg−1), reduced electrical conductivity, and suppressed enzyme activities due to frequent tilling and fertilization. Wetland soils exhibited the lowest values primarily due to water saturation, which limits organic matter decomposition and microbial activity. Land use changes notably reduced microbial diversity, with conversion from forest to arable land leading to habitat loss. Forest soils supported higher abundances of Proteobacteria (37.59%) and Actinobacteriota (34.73%), while arable soils favored nitrogen-fixing bacteria. Wetlands were characterized by chemoheterotrophic and anaerobic bacteria. Overall, these findings underscore the profound influence of land use on soil microbial communities and their functional roles, highlighting the need for sustainable management practices. [ABSTRACT FROM AUTHOR]

Wetland methane (CH4) emissions have a significant impact on the global climate system. However, the current estimation of wetland CH4 emissions at the global scale still has large uncertainties. Here we developed six distinct bottom‐up machine learning (ML) models using in situ CH4 fluxes from both chamber measurements and the Fluxnet‐CH4 network. To reduce uncertainties, we adopted a multi‐model ensemble (MME) approach to estimate CH4 emissions. Precipitation, air temperature, soil properties, wetland types, and climate types are considered in developing the models. The MME is then extrapolated to the global scale to estimate CH4 emissions from 1979 to 2099. We found that the annual wetland CH4 emissions are 146.6 ± 12.2 Tg CH4 yr−1 (1 Tg = 1012 g) from 1979 to 2022. Future emissions will reach 165.8 ± 11.6, 185.6 ± 15.0, and 193.6 ± 17.2 Tg CH4 yr−1 in the last two decades of the 21st century under SSP126, SSP370, and SSP585 scenarios, respectively. Northern Europe and near‐equatorial areas are the current emission hotspots. To further constrain the quantification uncertainty, research priorities should be directed to comprehensive CH4 measurements and better characterization of spatial dynamics of wetland areas. Our data‐driven ML‐based global wetland CH4 emission products for both the contemporary and the 21st century shall facilitate future global CH4 cycle studies. Plain Language Summary: Wetland CH4 emissions have a significant impact on the global climate system. However, the current estimation of wetland emissions at the global scale still has large uncertainties. This study developed a multi‐model ensemble (MME) estimate of the emissions using six distinct machine‐learning models and in situ CH4 fluxes from both chamber measurements and the Fluxnet‐CH4 network to reduce uncertainties. Precipitation, air temperature, soil properties, wetland type, and climate type were considered in developing the six models. The MME was then extrapolated to the global scale to estimate emissions from 1979 to 2099. We found that the annual wetland emissions will increase significantly by the last two decades of the 21st century. Northern Europe and near‐equatorial areas are the emission hotspots. Global CH4 has high emissions in the summer while low emissions in the winter. The spatial and temporal variations can be mainly explained by temperature, elevation, soil organic matter, and surface downward solar radiation. The uncertainties mainly come from in situ data with uneven spatial distribution and unchanged assumptions of the wetland area data. Key Points: A multi‐model ensemble is conducted to quantify the global wetland methane emissionsEstimated global wetland methane emissions are 146.6 ± 12.2 Tg CH4 yr−1 during 1979–2022 and will increase by 13.1% (SSP126), 26.6% (SSP370), and 32.0% (SSP585) by 2080–2099Temperature, elevation, soil organic matter, and surface downward solar radiation are the most important features in six machine learning wetland methane emission models [ABSTRACT FROM AUTHOR]

For wetlands to serve as natural climate solutions, accurate estimates of organic carbon (OC) sequestration rates in wetland sediments are needed. Dating using cesium-137 (137Cs) and lead-210 (210Pb) radioisotopes is commonly used for measuring OC sequestration rates in wetland sediments. 137Cs radioisotope dating is relatively simple, with calculations based on a single point representing the onset (1954) or peak (1963) of the 137Cs fallout. 210Pb radioisotope dating is more complex, as the calculations are based on multiple points. Here, we show that reliable dating of sediment cores collected from wetlands can be achieved using either 137Cs or 210Pb dating or their combination. However, 137Cs and 210Pb profiles along the depth of sediment cores need to be screened, analyzed, and interpreted carefully to estimate OC sequestration rates with high precision. To this end, we propose a decision framework for screening 137Cs and 210Pb profiles into high- and low-quality sediment profiles, and we compare dating using the 1954 and 1963 time markers, i.e., the rates of sedimentation and, consequently, OC sequestration over the past ∼ 60 years. Our findings suggest that 137Cs - and 210Pb -based OC sequestration rates are comparable, especially when using the 1963 (vs. 1954) time marker. [ABSTRACT FROM AUTHOR]

Coastal wetlands adapt to rising seas via feedbacks that build soil elevation, which lead to wetland stability. However, accelerated rates of sea-level rise can exceed soil elevation gain, leading to wetland instability and loss. Thus, there is a pressing need to better understand regional and landscape variability in rates of wetland soil elevation change. Here, we conducted a regional synthesis of surface elevation change data from mangrove forests and coastal marshes in the iconic Greater Everglades region of south Florida (USA). We integrated data from 51 sites in which a total of 122 surface elevation table-marker horizon (SET-MH) stations were installed. Several of these sites have been periodically monitored since the 1990s and are among the oldest SET-MH datasets in the world. Rates of surface elevation change ranged from −9.8 to 15.2 mm year−1, indicating some wetlands are keeping pace with sea-level rise while others are at risk of submergence and conversion to open water. Vertical accretion rates ranged from 0.6 to 12.9 mm year−1, and subsurface change rates ranged from −13.5 to 8.6 mm year−1. Rates of surface elevation change were positively related to subsurface change but not vertical accretion. There were no significant relationships between rates of surface elevation change and elevation (NAVD 88) or rates of sea-level rise. Site-specific examples indicate that hurricanes, plant productivity, hydrologic exchange, and proximity to sediment and nutrient inputs are critical but confounding drivers of surface elevation change dynamics in the Greater Everglades region. Collectively, our results reinforce the value of long-term SET-MH data that incorporate spatial variability for advancing understanding of surface elevation change dynamics in coastal wetlands. [ABSTRACT FROM AUTHOR]

Coastal wetlands experience acute and chronic disturbances which can affect rates of surface elevation change and vertical accretion of surface sediments. Disturbance can either amplify or impair the ability of wetlands to maintain their position within the tidal frame, with implications for their long-term persistence. Using an 8-year dataset collected from coupled surface elevation table-marker horizon (SET-MH) stations spanning riverine, bayside, and barrier island settings in the Apalachicola Bay region of north Florida, USA, this study investigated decadal-scale surface elevation change and vertical accretion rates to assess wetland vulnerability to acute (Hurricane Michael) and chronic (relative sea-level rise; RSLR) disturbance in different geomorphic settings. All sites had long-term accretion rates that exceeded rates of surface elevation change (pre-Michael), indicating that surface accretion was not a good indicator of changes in surface elevation for any of these coastal geomorphic settings. Hurricane Michael increased surface elevation change rates at bayside and riverine sites; barrier island sites consistently displayed the lowest surface elevation change rates, which did not differ between pre- and post-Michael periods. Accretion rates were greatest in the riverine sites, which were characterized by highly organic soils. Barrier island and bayside sites demonstrated elevation and accretion deficits relative to the rate of RSLR for Apalachicola Bay between 2010 and 2022, indicating high vulnerability of these sites to chronic increases in sea level. These estimates of marsh resilience relied exclusively on rates of vertical change and neglecting to account for lateral erosion failed to predict that each of the three barrier island sites experienced rapid loss of the seaward SET-MH stations during the observation period. These results provide evidence of different vertical change responses among coastal wetlands of three geomorphic settings exposed to hurricanes and RSLR in the same region and suggest different timelines for long-term persistence of these sites. [ABSTRACT FROM AUTHOR]

Wetland methane (CH4) fluxes are highly variable over spatial and temporal scales due to variations in CH4 production, oxidation, and transport. While some aspects of temporal variability in CH4 fluxes are well documented, diel variability is poorly constrained, and studies report conflicting findings, making it difficult to generalize. Topographic, geochemical, hydroclimatic, and vegetative variability can result in characteristically different "patches" that likely influence differences in diel patterns. We investigated diel patterns of CH4 fluxes from a large seasonal‐mineral soil wetland in Maryland (USA) across three functionally unique patches: two with vegetation (emergent and submerged aquatic vegetation) and one without (open water) during the summer of 2021. To explore the relationships between vegetation, environmental conditions, and flux patterns, we also measured physiochemical variables (air and water temperature, pH, relative humidity, PAR, dissolved oxygen, and water depth). To our knowledge, this is the first study comparing diel variability using chambers across such distinct vegetation patch types. We found that diel patterns were strongly linked to patch types: CH4 fluxes from the emergent vegetation did not display a consistent diel pattern, while fluxes from the submerged vegetation and no vegetation patches frequently peaked at 13:00 and 05:00, respectively. These differences could be a direct result of vegetation impact on production, oxidation, and/or transport of CH4 or on conditions covarying with patch type. This study contributes to the growing understanding of how CH4 fluxes vary spatially over diel cycles and emphasizes the importance of considering spatially varying diel patterns when estimating fluxes. Plain Language Summary: Methane (CH4) emissions from wetlands are known to vary over space and time, to be largely controlled by vegetation, and exhibit strong seasonal patterns. Yet daily patterns are not well characterized due to the limited number of studies and to difficulties in obtaining nighttime measurements. To address this, we investigated CH4 flux patterns over day and night cycles in patches characterized by emergent, submerged, or no vegetation in a temperate freshwater herbaceous wetland. We show that daily patterns of CH4 emissions are strongly linked to the type of vegetation present but the mechanistic influence of plants on production and consumption is unclear. This work contributes to the growing understanding of how CH4 varies within wetland landscapes over time. Key Points: Vegetation presence and type can control day and nighttime methane (CH4) fluxesPatterns in CH4 flux over diel cycles and across vegetation patch types vary such that a single daily measurement may not adequately capture variability of diel fluxesVegetation function that facilitates both production and oxidation of CH4 can lead to unpredictable diel patterns in CH4 flux [ABSTRACT FROM AUTHOR]

Green rusts (GR) are mixed-valence iron (Fe) hydroxides which form in reducing redox environments like riparian and wetland soils and shallow groundwater. In these environments, silicon (Si) can influence Fe oxides' chemical and physical properties but its role in GR formation and subsequent oxidative transformation have not been studied starting at initial nucleation. Green rust sulfate [GR(SO4)] and green rust carbonate [GR(CO3)] were both coprecipitated from salts by base titration in increasing % mol Si (0, 1, 10, and 50). The minerals were characterized before and after rapid (24 h) aqueous air-oxidation by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fe extended x-ray absorption fine structure spectroscopy (EXAFS), and N2-BET surface area. Results showed that only GR(SO4) or GR(CO3) was formed at every tested Si concentration. Increasing % mol Si caused decreased plate size and increased surface area in GR(CO3) but not GR(SO4). GR plate basal thickness was not changed at any condition indicating a lack of Si interlayering. Air oxidation of GR(SO4) at all % mol Si contents transformed by dissolution and reprecipitation into lepidocrocite and goethite, favoring ferrihydrite with higher % Si content. Air oxidation of GR(CO3) transformed into magnetite and goethite but increasing Si caused GR to oxidize while retaining its hexagonal plate structure via solid-state oxidation. Our results indicate that Si has the potential to cause GR to form in smaller particles and upon air oxidation, Si can either stabilize the plate structure or alter transformation to ferrihydrite. [ABSTRACT FROM AUTHOR]

The low rice production level in Africa is attributed to poor soil fertility despite the potential for rice cultivation in the inland valleys. This study was conducted to evaluate soil characteristics in some lowlands that have been continuously and intensively used for rice production for over two decades in southwestern Nigeria. Soil physical, chemical, and mineralogical properties, as well as phosphorus sorption characteristics, were assessed in soil samples collected from diagnostic horizons of profiles in six benchmark soils. The results show kaolinite, quartz, potassium(K)-feldspars, and mixed-layered smectite as the predominant minerals. The iron oxide fractions indicate that the soils are at varying degrees of development where the soils at the advanced stage of development are predominantly rich in kaolinite and quartz with a high concentration of total pedogenic iron oxide and generally low in soil fertility. Soil phosphorus buffering capacity is low and varies inversely with pH, confirming the deficiency of phosphorus at low pH. Short-range-order (SRO) iron (Fe) oxides show a strong affinity for phosphorus and this is stronger at lower soil horizons and mediated by some redoxomorphic reactions. The SRO iron oxide concentration has more influence on phosphorus retention in soils rather than the absolute concentration of iron oxides. The study concludes that SRO Fe oxides and soil pH are the major edaphic factors playing a prominent role in phosphorus retention and availability in the wetland soils rather than the clay minerals. [ABSTRACT FROM AUTHOR]

Reductive dissolution of barium (Ba) sulfate in wetland soils may increase Ba bioavailability in the environment, yet no information is available regarding Ba remediation using biochar. This study investigated the effectiveness of sugarcane (Saccharum officinarum) straw biochar pyrolyzed at 350 °C (BC350), 550 °C (BC550), and 750 °C (BC750) in inhibiting barite dissolution and, consequently, Ba availability in a soil artificially spiked with barite and flooded for 365 days. Increasing pyrolysis temperature alters the carbon structure, and increases dehydration and depolymerization, resulting in more stable biochar that releases less DOC (8.6-fold decrease from BC350 to BC750). Additionally, high-temperature biochar (BC750) had 1.7 times higher carbon (C) content, 2.4 times higher ash content, and a 13.1 times greater specific surface area (SSA) than low-temperature biochar (BC350). Amending soil with BC750 increased pH but did not promote reducing conditions, and thus did not promote barite dissolution. Conversely, greater DOC in low-temperature biochar, particularly BC350, favored reducing conditions and increased barite dissolution by 23%, with BC550 also showing an 18% increase. This enhancement led to a greater pool of Ba sorbed into more labile exchangeable sites. In summary, pyrolysis temperature affects biochar attributes, which in turn influences the soil geochemical environment and Ba speciation. Low-temperature biochar (BC350) shows potential as an amendment to increase the bioavailable Ba pool in assisted remediation programs, such as biochar-assisted phytoremediation. Highlights: • Biochar pyrolysis temperature affected both redox potential and barite dissolution. • BC750 mitigated barite dissolution while modifying exchangeable sorption sites. • DOC release from low temperature biochar promoted barite reductive dissolution. • BC350 may enhance biochar-mediated phytoremediation applications. [ABSTRACT FROM AUTHOR]

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The biomass of wetland plants is highly responsive to environmental factors and plays a crucial role in the dynamics of the soil organic carbon (SOC) pool. In this study, we collected and analyzed global data on wetland plant biomass from 1980 to 2021. By examining 1134 observations from 182 published papers on wetland ecosystems, we created a comprehensive database of wetland plant above-ground biomass (AGB) and below-ground biomass (BGB). Using this database, we analyzed the biomass characteristics of different climate zones, wetland types and plant species globally. Based on this, we analyzed the differences between the biomass of different plant species and the linkage between AGB and BGB and organic carbon. Our study has revealed that wetland plant AGB is greater in equatorial regions but BGB is highest in polar areas, and lowest in arid and equatorial zones. For plant species, the BGB of the Poales is higher than the AGB but Caryophyllales , Cyperales and Lamiales have higher AGB. Moreover, our findings indicate that BGB plays a more significant role in contributing to the organic carbon pool compared to AGB. Notably, when BGB is less than 1 t C ha−1, even slight changes in biomass can have a significant impact on the organic carbon pool. And we observed that the SOC increases by 5.7 t C ha−1 when the BGB content is low, indicating that the SOC is more sensitive to changes in biomass under such circumstances. Our study provides a basis for the global response of AGB and BGB of wetland plants to organic carbon. [ABSTRACT FROM AUTHOR]

Climate change and invasive species represent two intertwined global environmental challenges profoundly affecting freshwater ecosystems. This study uses Ecological Niche Modeling along with risk screening to delve into the preferences and potential distribution of Potamopyrgus antipodarum, an invasive species, in relation to climate zones and habitat types, shedding light on the critical importance of coastal wetlands and high soil organic carbon content in shaping habitat suitability. Our findings underscore that P. antipodarum exhibits a distinct affinity for cool temperate, moist climates, as well as temperate floodplain rivers, wetlands, and coastal areas. Notably, coastal wetlands, endowed with elevated soil organic carbon levels, emerged as pivotal habitats for this species. Projections indicated a significant expansion in North America, potentially extending into South America. Türkiye reveals an intriguing alignment between its habitat and the natural distribution areas of P. antipodarum, presenting potential for habitat contraction while still retaining a broader range compared to other regions. These potential expansions were predominantly driven by climate suitability, playing a pivotal role in the invasiveness of P. antipodarum, with anticipated future climate regimes exerting substantial influence on its dispersal capabilities. [ABSTRACT FROM AUTHOR]

Coastal wetland soils are frequently underlain by sulfidic materials. Sea level fluctuations can lead to oxidation of sulfidic materials in acid sulfate soils (ASS) and increased acidity which mobilises trace metals when water levels are low, and inundation of coastal wetland soils and reformation of sulfidic materials when water levels are high. We measured the effect of surface water level fluctuations in soils from coastal wetland sites under four different vegetation types: Apium gravedens (AG), Leptospermum lanigerum (LL), Phragmites australis (PA) and Paspalum distichum (PD) on an estuarine floodplain in southern Australia. We assessed effects of fluctuating water levels on reduced inorganic sulfur (RIS) in terms of acid volatile sulfide (AVS), chromium reducible sulfur (CRS) and trace metals (Fe, Al, Mn, Zn, Ni). Intact soil cores were incubated under dry, flooded and wet–dry cycle treatments of 14 days for a total of 56 days. The flooded treatment increased RIS concentrations in most depths in the AG, PA and PD sites. Lower CRS concentrations occurred in all sites in the dry treatment due to oxidation of sulfidic materials when the surface layer was exposed to lower water levels. CRS was positively correlated with SOC in all treatments. The highest net acidity occurred in the dry treatment and lowest occurred in the flooded treatment in most sites. Inundation with seawater caused SO42− reduction and decreased soluble Fe in the PA and PD sites. General decreases in Al, Zn and Ni concentrations in flooded treatments may have been due to adsorption onto colloids or co‐precipitation with slight increases in pH. SO42− concentrations decreased in the LL, PA and PD sites in the flooded treatment due to reformation of pyrite. In general, accumulation of RIS in soils under different vegetation types following brackish water inundation varied according to vegetation type, which may be linked to differences in organic material input and particle size distribution. Geochemical characteristics reflected whether oxidation or reduction processes dominated at each site in the wet–dry cycle treatments, with oxidation dominating in the LL and PA sites and reduction dominating in the AG and PD sites. This is likely due to more readily decomposable organic matter forming sulfidic materials during short periods of inundation. [ABSTRACT FROM AUTHOR]

Salt‐tolerant Tamarix chinensis roots are crucial in preserving wetland soil and carbon sequestration, which is essential for wetland ecology. Soil‐water‐salt conditions influence the growth of these roots in coastal saline areas, but the specific factors and their effects remain unclear. Using principal component and partial least square–structural equation modelling (SEM) methods, we studied T. chinensis root features in six Yellow River delta communities. Results showed varied root features across locations, with larger roots further inland. Root growth negatively correlated with soil texture and salinity and positively with groundwater levels. Soil texture and salinity decreased with distance from the coast, while groundwater increased with distance from the Yellow River. This suggests that geographical location influences soil‐water‐salt conditions, impacting root characteristics. The principal component analysis–derived root feature index captured 56.7% of root feature variation. SEM revealed geographical locations indirectly influence root features, with the Yellow River's proximity primarily affecting them through groundwater and coastal distance influencing via soil sand content and salinity. The study underscores the importance of these findings for wetland conservation and ecology. [ABSTRACT FROM AUTHOR]

Aim: Revealing the role of regional species pool size in community assembly rules is essential for extending the species‐pool framework to large‐scale community ecology, and thus for more comprehensive understanding of biodiversity formation. However, little has been done to couple the regional species‐pool effect into local ecological processes in soil fungal communities, which play essential roles in ecosystems worldwide. Here, we performed large‐scale soil surveys of fungal communities to examine the linkage between regional species pool size and Dispersal–Selection Relationships (DSRs), and their relations to community structure. Location: China. Time period: July–August 2019. Major taxa studied: Fungal communities. Methods: By conducting the nationwide soil survey of ~1200 samples from various ecosystems across China, including agricultural, forest, grassland, and wetland soils, we examined the linkage between regional species pool size and DSRs, and their relationship to fungal community structure. Results: We found that selection was negatively related to dispersal, which was consistent with the general view that the strength of selection is weakened by dispersal homogenization, and that this relationship was stronger in regions with larger species pools. Moreover, an increase in community dispersion was correlated with stronger effect size of DSRs, implying greater heterogeneity among fungal communities under larger species pools. Main conclusions: Our study clearly illustrates the association of regional species pool size with local assembly rules and community formation of soil fungi across terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

The soil mantle of the tropical karstic landscapes of Southern Mexico was shaped by specific processes of pedogenesis and long-term human impacts of ancient Maya agriculture. To understand the interaction between natural and human-induced soilforming processes in the calcareous mountains of Chiapas state, we studied soil toposequences around the Classic Maya site of Budsilhá and related them to the archaeological evidence of settlement and land-use distribution. Soil chemical analysis, micromorphological observations, and clay mineral identification were carried out in key soil profiles at the main geoforms. Limestone hills are occupied by shallow Rendolls which are usually perceived as incipient soils. However, high content of silicate clay composed of kaolinite and vermiculite and ferruginous clayey soil material observed at macro- and microscale backed the hypothesis that these soils were formed from the residues of thick Terra Rossa after their erosion. Swampy lowlands are occupied by thick clayey gleyic soils with clay mineral assemblages similar to those in the upland Rendolls. We suppose that the mineral matrix of the lowland soils is largely derived from the pedosediments of eroded upland Terra Rossa, which lost original ferruginous pigmentation and aggregation due to redoximorphic processes. Some wetland soils contain neoformed gypsum that is atypical for humid tropics; sulfidesulfate transformation under fluctuating redox conditions could promote gypsum synthesis. Ancient Maya land use was closely related to soil-geomorphic conditions: settlements with homegardens occupied calcareous hills, whereas the primary agricultural domain was developed on lowland soils after their drainage by artificial canals. [ABSTRACT FROM AUTHOR]

The intensification of the global hydrological cycle is anticipated to increase the variability of precipitation patterns. Brackish wetlands respond to changes in precipitation patterns by regulating the absorption and release of CO2 and H2O to maintain the stability of ecosystem functions. However, there is limited understanding of how the inter‐seasonal precipitation distribution (SPD) affects ecosystem CO2 and H2O exchange compared with annual precipitation totals.Here, we conducted four consecutive years of field experiments in a brackish wetland, manipulating the proportion of precipitation across different seasons while maintaining a constant annual precipitation total. We utilized five inter‐SPD proportions (+73%, +56%, control (CK), −56%, −73%) to examine the effects of SPD on ecosystem CO2 and H2O exchange.Our findings revealed that the annual ecosystem CO2 and H2O fluxes showed a trend of decreasing with the decrease in spring precipitation distribution. Among them, the annual net ecosystem CO2 exchange, evapotranspiration, carbon use efficiency and water use efficiency were shown to be more sensitive to decrease in spring precipitation distribution and increase in summer and autumn precipitation distribution. This negative asymmetric response pattern suggests that annual ecosystem CO2 and H2O exchange is primarily governed by seasonal precipitation variability, with spring soil water–salt dynamics identified as the key driver. Therefore, this association can be explained by the fact that drought of the early growth stage exacerbates soil salinization and inhibits vegetation colonization and growth, thereby greatly impairing the annual CO2–H2O exchange capacity of brackish wetlands.Our results emphasized that the spring extreme precipitation‐induced soil water–salt conditions will greatly influence CO2 and H2O exchange in brackish wetlands in the future. These findings are crucial for improving predictions of the carbon sequestration and water‐holding capacity of brackish wetlands. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Disparities in pH, conductivity, organic carbon (OC), nutrients, and moisture between the Asan Wetland and its periphery in the Western Himalaya, India, highlight the need to investigate influencing factors. This study thus addresses two gaps: (1) identifying key drivers for alkaline pH and elevated wetland concentrations and (2) understanding how different values outside the wetland relate to ecological processes. Asan Wetland soil samples, collected on April 15, 2023, underwent analysis for pH, electrical conductivity (EC), organic carbon (OC), organic matter (OM), available nitrogen (N), available phosphorus (P), potassium (K), sodium (Na), calcium (Ca), moisture content (M), total organic carbon (TOC), and total organic matter (TOM) using standard laboratory procedures, APHA, CPCB, and standard manual techniques. Within the wetland, results indicated that the soil is more alkaline (pH 8.50 ± 0.13) than the periphery in the concentrations of EC, N, K, and M were found to be higher compared to the corresponding concentrations outside the wetland, with mean values of 1.10 ± 0.15 ds/m, 364 ± 117.13 kg/ha, 86.42 ± 21.64 kg/ha, and 20.87 ± 1.50%, respectively. Conversely, outside the wetland, higher values of OC, OM, P, Na, Ca, TOC, and TOM were recorded (0.39 ± 0.23%, 0.66 ± 0.39%, 0.82 ± 0.35 ppm, 80.45 ± 8.46 ppm, 268.12 ± 61.12 ppm, 56.80 ± 0.33%, and 97.70 ± 0.57%, respectively). pH, EC, K, Ca, Na, and moisture content variations indicate location‐based differences. pH, TOM, TOC, and soil moisture were positively correlated within wetlands but negatively correlated with Na and N. In addition, moisture was positively correlated with pH and N but negatively correlated with Ca, K, Na, and P. The study concluded that the Asan Wetland exhibits distinct soil characteristics compared to its periphery, exhibiting location‐based differences while emphasizing these factors' interconnectedness. [ABSTRACT FROM AUTHOR]

The editorial in "Frontiers in Marine Science" explores the cycling of biogenic elements and their microbial transformations in marine ecosystems. It highlights the impact of global climate change on element distribution, the role of microorganisms in element transformations, and the responses of microbial communities to environmental changes. The research presented in the editorial focuses on carbon, nitrogen, and sulfur cycling, emphasizing the importance of understanding these processes for marine ecosystem health and sustainability. The authors call for further research to address the multi-level responses of biogenic element cycling to global changes and to develop innovative approaches using artificial intelligence in marine science. [Extracted from the article]

Organohalides are widespread pollutants that pose significant environmental hazards due to their high degree of halogenation and elevated redox potentials, making them resistant to natural attenuation. Traditional bioremediation approaches, primarily relying on bioaugmentation and biostimulation, often fall short of achieving complete detoxification. Furthermore, the emergence of complex halogenated pollutants, such as per‐ and polyfluoroalkyl substances (PFASs), further complicates remediation efforts. Therefore, there is a pressing need to reconsider novel approaches for more efficient remediation of these recalcitrant pollutants. This review proposes novel redox‐potential‐mediated hybrid bioprocesses, tailored to the physicochemical properties of pollutants and their environmental contexts, to achieve complete detoxification of organohalides. The possible scenarios for the proposed bioremediation approaches are further discussed. In anaerobic environments, such as sediment and groundwater, microbial reductive dehalogenation coupled with fermentation and methanogenesis can convert organohalides into carbon dioxide and methane. In environments with anaerobic‐aerobic alternation, such as paddy soil and wetlands, a synergistic process involving reduction and oxidation can facilitate the complete mineralization of highly halogenated organic compounds. Future research should focus on in‐depth exploration of microbial consortia, the application of ecological principles‐guided strategies, and the development of bioinspired‐designed techniques. This paper contributes to the academic discourse by proposing innovative remediation strategies tailored to the complexities of organohalide pollution. [ABSTRACT FROM AUTHOR]

Wetland ecosystem service function provides and maintains the Earth's life system, which supports human and social development. However, in recent years, with the intensification of human social activities, the wetland area in northeast China has been reduced, and wetland ecosystem service function has been damaged. This paper evaluates the ecosystem service function of wetlands in northeast China based on the InVEST model, taking 40 prefecture-level cities as the evaluation unit, calculating the carbon stock, soil retention, and habitat quality of the wetlands in the study area and analyzing the drivers of changes in ecosystem service function using the PLUS model. The following results were obtained: temporally, the wetland carbon stock decreased from 754 Tg in 2000 to 688 Tg in 2020; the wetland soil retention increased from 24,424 Tg in 2000 to 33,160 Tg in 2010, and then decreased to 28,765 Tg in 2020; and the quality of wetland habitats was roughly unchanged. The wetland habitats in the study area were categorized into 5 types, classified as I, II, III, IV, or V, and the spatial changes in the 40 prefecture-level cities in northeast China were analyzed. The driving factors affecting the change in the wetland ecosystem service function were further analyzed, mainly focusing on changes in the wetland area itself. The influence of other land-use types and the influence of related policies were analyzed in three aspects, among which the GDP and spatial density of the population are social factors, and the elevation and slope are natural factors that provide larger contributions to the change in wetland area. The reduction in forest and grassland areas and the increase in cultivated land and construction land areas have a negative effect on the ecosystem service function of wetlands, and the implementation of relevant wetland protection policies promotes the ecosystem service function of wetlands. According to the problems faced by wetlands in different regions, the government formulates strategies that are in line with local development, with a view to implementing wetland ecological development in the northeast region in the new context, which will help to realize intensive land use and stimulate the vitality of the region. [ABSTRACT FROM AUTHOR]

The article focuses on how meteorological factors, such as rainfall and temperature, influence changes in land use within the marshes of the Al-Majar Al-Kabir region in southern Iraq. Topics include the impact of temperature and rainfall on land cover types, the use of Landsat satellite data for monitoring these changes, and the implications for soil conservation and marshland management.

Ecosystem services comprise all the benefits that humanity obtains from ecosystems. Within the regulation services, wetlands soils have an important role in regulating the water cycle through water retention and the climate through carbon storage and sequestration. The objective of this research was to estimate the water retention capacity and the soil organic carbon content in the superficial portion of Ramsar wetlands soils in Quintana Roo, Mexico, to provide elements to the ecologic and economic valuation of regulation ecosystem services. A total of 268 soil samples were collected from the upper 20 cm soil layer, soil samples were processed and analyzed to obtain edaphic properties and organic carbon. We assessed the effect of 1) seasonality, 2) vegetation structure, and 3) soil type in the response variables water retention and organic carbon storage. The results indicate that the volumetric content and saturation degree were different among wetlands. Seasonality was not a significant factor in the assessment of these two regulation ecosystem services. The mean water storage capacity was 0.65 g water/cm3 of soil, representing from 500 to 1000 L water/m3 soil. The greatest carbon storage values were associated with mangroves established on Solonchak, with values between 5 and 8 Mg C/ha. The type of soil is the grouping variable that reported differences in water and carbon content in the soil, with Histosols retaining more water, but Solonchacks storing more carbon. [ABSTRACT FROM AUTHOR]

The roles of Asgard archaea in eukaryogenesis and marine biogeochemical cycles are well studied, yet their contributions in soil ecosystems remain unknown. Of particular interest are Asgard archaeal contributions to methane cycling in wetland soils. To investigate this, we reconstructed two complete genomes for soil-associated Atabeyarchaeia, a new Asgard lineage, and a complete genome of Freyarchaeia, and predicted their metabolism in situ. Metatranscriptomics reveals expression of genes for [NiFe]-hydrogenases, pyruvate oxidation and carbon fixation via the Wood-Ljungdahl pathway. Also expressed are genes encoding enzymes for amino acid metabolism, anaerobic aldehyde oxidation, hydrogen peroxide detoxification and carbohydrate breakdown to acetate and formate. Overall, soil-associated Asgard archaea are predicted to include non-methanogenic acetogens, highlighting their potential role in carbon cycling in terrestrial environments. The roles of Asgard archaea in soil ecosystems are unclear. In this study, the authors report complete genomes and metatranscriptomic data of Asgard archaea that indicate a role in production and consumption of carbon compounds known to serve as substrates for methane production in wetland soils. [ABSTRACT FROM AUTHOR]

Natural wetlands are mostly nitrogen-limited ecosystems, while reclamation stimulates the loss of nitrogen (N) in soils by shifting the N regime. To investigate the microbial mechanisms of the N regime shift, we first conducted a global meta-analysis to quantify the wetland reclamation impacts on soil mineral N pools and then a field campaign to sample 24 soil cores up to 100 cm depth in a natural wetland and a 23-year cultivated soybean field from the Sanjiang Plain in northeastern China. After wetland reclamation, the N regime was shifted to cause a potential risk of massive N loss in soils; their microbial mechanisms were revealed through metagenomic data. In cropland, the relative abundance of genes involved in nitrification and assimilatory nitrate reduction to ammonia (ANRA) were enriched while those in N fixation, mineralization, denitrification, and dissimilatory nitrate reduction to ammonia (DNRA) were diminished. Wetland reclamation substantially enhanced the relative abundance of genes involved in nitrification (except for genes for ammonia oxidation to NH2OH) and denitrification in surface (0–30 cm) soils but decreased them in subsurface (30–100 cm) soils. After wetland reclamation, the relative abundance of genes involved in denitrification and DNRA significantly reduced in spring and summer, but such patterns were not found in autumn and winter. This change enhanced potential microbial-driven N loss in spring and summer. The metagenomic data serve as surrogate data sources for quantifying soil roles on soil N cycles under land use change. [ABSTRACT FROM AUTHOR]

Introduction: Water pollution is one of the main environmental problems affecting Cuba. The galvanic and leather tanning industries in the same country generate wastewater contaminated with chromium which can be treated using constructed wetlands. Objective: To evaluate chromium removal behavior in experimental subsurface wetlands. Materials and Methods: Two experimental systems consisting of horizontal subsurface flow wetlands were constructed: one planted with Cyperus Alternifolius and the other with two varieties of Heliconia (Rostrata and Wagneriana), using red ferrallitic soil as substrate. The Atomic Absorption Spectrometry method was used for the determination of total chromium and Excel of the Office package in its version 16.0.17726 was the software adopted for statistical processing. Results and Discussion: The Cyperus Alternifolius was the species that showed the best assimilation, managing to transport the metal to the leaves. The kinetics of chromium removal in the wetland and in the soil used as substrate were evaluated, demonstrating the importance of plants and associated microorganisms in the retention of the metal, with higher retention in the wetland. Chromium removal efficiencies of over 98% were obtained. Conclusions: Using the Cyperus Alternifolius plant together with the red ferrallitic soil, and performing the corresponding scaling with the kinetic constants obtained, it is possible to construct a treatment system that efficiently removes chromium from wastewater associated with the galvanic industry and tanneries. [ABSTRACT FROM AUTHOR]

Microbial necromass carbon (MNC) has been identified as an essential component of a persistent soil carbon pool. However, the contribution of MNC to soil organic carbon (SOC) in wetlands remains unclear. This study aims to explore the contribution of MNC to SOC and the factors controlling its distribution in wetlands. The distribution pattern of MNC in drawdown areas was investigated in the inlet and center of the Dongting Wetland, China. Random forest modeling was performed to determine the relative importance of environmental variables to MNC. A partial least squares path model was performed to further explore the direct and indirect effects of environmental variables on MNC. The analyses showed that the MNC content was 2652.70–3314.64 mg kg−1, accounting for 23.16–31.65% of SOC in wetland soils. Compared to bacterial necromass carbon (BNC), fungal necromass carbon (FNC) contributed more to SOC accumulation (over 70% of total MNC) in wetland soils. MNC content and the contribution of BNC to MNC increased with soil depth. In addition, MNC in wetland soils was directly affected by dissolved total nitrogen (DTN) and dissolved organic carbon (DOC)/SOC (p < 0.001; standardized total effect = 0.81). The pH indirectly affected MNC by regulating carbon and nitrogen content, with a standardized total effect of 0.48. In wetland soils, the lower MNC content and lower contribution to SOC may be supported by the slow accumulation of necromass and potential necromass mining in nutrient-poor conditions. Carbon and nitrogen availability played a crucial role in controlling the MNC turnover process in wetland soils. [ABSTRACT FROM AUTHOR]

Fish production integrates changes in biomass from growth, reproduction, and mortality, and is a useful indicator for fisheries management. However, calculation of fish production has been limited by the intensive requirements for data on abundance, biomass, age structure, and vital rates, and so it is uncommon to find estimates of fish production for wetlands. We developed an approach to directly estimate production that is suitable for data-limited systems: a continuous time model of production describing individual growth over short time intervals with continuous time models of abundance and biomass over longer timescales. We applied this model for 18 Great Lakes coastal wetlands (GLCWs) on Lake Ontario, including Big Island Wetland (BIW). In BIW, most species were dominated in abundance and biomass by younger cohorts and, as a result, these young, fast-growing individuals contributed disproportionately to fish production. In total, BIW produced 336.1 kg·ha·year of fish and the other 17 neighbouring ranged between 447.7 and 1119.9 kg·ha·year. These are some of the first estimates of fish production for GLCWs, highlighting their value for managing Great Lakes fisheries. [ABSTRACT FROM AUTHOR]

Wetlands are characterised by distinct hydrological regimes and have significant importance in the global carbon cycle, having the potential to reduce carbon emissions through long-term carbon storage in the soil. In this study, carbon dynamics were simulated using a process-based model DeNitrification-DeComposition (DNDC), for two locations along Dâmbovița River case study area. These scenarios took into consideration the interconnection of soil parameters, hydrology, meteorological conditions and vegetation type. The findings showed that soil CO2 emissions are positively and strongly correlated with air temperature and soil moisture, with changes in the water content of the soil regime having the greatest impact on CO2 fluxes. Also, the model simulations have been validated by statistical analysis of uncertainties with the values of CO2 fluxes measured in situ using the dynamic closed chamber method. By comparing DNDC outputs with field measurements, the performance of the model was evaluated in different environmental conditions and the results were consistent, which increased confidence in its application for assessing wetland ecosystems. These results contribute to a more comprehensive understanding of the carbon cycle in wetlands and an improved estimation of the effects of climate change on the dynamics of carbon in these ecosystems. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau is well‐known for its expansive wetland environments. Hydric soils, a fundamental component of these environments, exhibit diverse hydraulic characteristics attributable to their varied botanical and mineralogical composition and their inherent porous structures. Nonetheless, research on the hydraulic properties of such soils in Tibet remains notably underrepresented relative to European and Canadian regions. Consequently, in this study, we evaluate the effectiveness of different unsaturated hydraulic schemes in equilibrium and examine the parameter uncertainty of 14 undisturbed samples collected from four soligenous wetlands. The findings suggest that both the van Genuchten and Kosugi functions, when integrated with the Peters‐Iden‐Durner (PDI) model, yield a nearly consistent fit to experimental observations and demonstrate strong identifiability of parameters. This indicates that the PDI model can accurately characterize hydraulic properties across the complete moisture range of hydric soils. Analysis of samples with a low clay content and no sphagnum suggests that the intertwined, twisted, and hollow residues of herbaceous vascular tissues do not create a distinct, independent macro‐pore system. Therefore, the unimodal scheme integrating the PDI model is adequate. However, for samples that exhibit nonmonotonicity of the first‐order derivative of the retention curve, such as uncompacted samples containing sphagnum or samples rich in clay, the integration of the PDI model into the bimodal scheme boosts accuracy while having almost negligible impact on identifiability. The varied observed hydraulic properties of only 14 samples underscore the necessity for extensive hydric‐soil sampling and hydraulic analysis across the expansive and varied wetland landscapes on the Tibetan Plateau. Plain Language Summary: The alpine wetlands of the Tibetan Plateau have given rise to a diverse array of wetland soils. Considering the plateau monsoon climate characteristics, this study focuses on soil water retention and unsaturated hydraulic conductivity across the complete soil moisture range. The results indicate that, regardless of the non‐hydraulic physical properties of these wetland soils, employing a hydraulic model that integrates capillary flow models with a simplified film flow model can significantly enhance the accuracy of the inverse modeling method in determining hydraulic properties. Given the diverse wetland environments and the vast expanse of the Tibetan Plateau, it is essential to conduct extensive field soil sampling and laboratory analysis to gain a comprehensive understanding of the soil hydraulic properties. Currently, the hydraulic parameters provided by this study may be reasonable choices for simulating land surface and hydrological processes related to the plateau wetland soils. Key Points: A pioneering analysis determines the hydraulic properties of hydric soils on the Tibetan PlateauDiverse hydraulic properties and their association with varied vegetation remnants and mineral compositions are revealedA basis is provided for selecting soil unsaturated hydraulic schemes for Tibetan wetlands and peatlands [ABSTRACT FROM AUTHOR]

The Intermediate Disturbance Hypothesis (IDH) posits that maximal plant biodiversity is attained in environments characterized by moderate ecological disturbances. Although the applicability of the IDH to microbial diversity has been explored in a limited number of studies, there is a notable absence of experimental reports on whether soil microbial 'activity' demonstrates a similar response to the frequency or intensity of environmental disturbances. In this investigation, we conducted five distinct experiments employing soils or wetland sediments exposed to varying intensities or frequencies of disturbances, with a specific emphasis on disturbances associated with human activity, such as chemical contamination, hydrologic changes, and forest thinning. Specifically, we examined the effects of bactericide and heavy metal contamination, long-term drainage, tidal flow, and thinning management on microbial enzyme activities in soils. Our findings revealed that microbial enzyme activities were highest at intermediate disturbance levels. Despite the diversity in experiment conditions, each trial consistently demonstrated analogous patterns, suggesting the robustness of the IDH in elucidating microbial activities alongside diversity in soils. These outcomes bear significant implications for ecological restoration and management, as intermediate disturbance may expedite organic matter decomposition and nutrient cycles, crucial for sustaining ecosystem services in soils. [ABSTRACT FROM AUTHOR]

The occurrence of vegetation degradation may greatly affect the soil organic carbon (SOC) composition and carbon pool of wetland meadows in the Qinghai-Tibet Plateau (QTP). However, it is currently unclear how SOC will change under different degrees of degradation. Therefore, we studied the wetland meadows of Maqu, China on the eastern edge of the QPT with different degrees of vegetation degradation (undegraded (UD), light degraded (LD), moderately degraded (MD) and severely degraded (HD)), analyzed the impact of vegetation degradation on SOC composition, and calculated the carbon storage management index (CPMI). The results showed that the degradation of vegetation significantly reduces the SOC content of the Maqu wetland. With the aggravation of vegetation degradation, the proportion of SOCs in different fractions showed significant differences, especially in the topsoil layer. The mean CPMI value from 0-40 cm of LD, MD and HD has decreased by 47.29%, 41.64%, and 51.73% respectively compared to UD. It can be seen that vegetation degradation significantly increasing the carbon pool activity index (CAI) of Maqu. Our study suggested that vegetation degradation could considerably reduce the carbon pool index, which decrease the storage of wetland carbon, gradually undermine or even depleting the carbon sink capacity of QTP wetland system. [ABSTRACT FROM AUTHOR]

Invasive Spartina alterniflora has significant impacts on sediment carbon pool and turnover in the tidal wetlands of estuaries and coasts. Yet, how this exotic S. alterniflora affects sediment organic carbon mineralization dynamics remains poorly understood. In this study, sediment geochemical properties, organic carbon fractions, and mineralization dynamics were examined in a native Cyperus malaccensis habitat and three invasive S. alterniflora habitats (6-, 10-, and 14-year-old) in summer and winter. We found that invasive S. alterniflora generally increased sediment total organic carbon and their labile fraction contents. The organic carbon mineralization rates and cumulative carbon mineralization amounts were significantly influenced by invasive S. alterniflora, and their values increased with this exotic plant invasion chronosequences. The mineralization rates and cumulative mineralization amounts were also characterized by higher values in surface sediment (0 - 10 cm depth) compared to subsurface sediment (10 - 20 cm depth) and by seasonal variations with higher values in summer than in winter. The sediment organic carbon labile fractions, rather than total organic carbon, were the most important factor affecting carbon mineralization dynamics. The cumulative carbon mineralization amounts exhibited an excellent fit to the first-order kinetic equation (R2 = 0.93). The changes in modeled kinetic parameters (potential carbon mineralization amounts (C0) and carbon mineralization rate constant (k)) among these four habitats were similar to carbon mineralization rates, implying invasive S. alterniflora promoted the availabilities of organic compounds for microbial respiration metabolism. Overall, our findings highlighted the importance of S. alterniflora invasion in accelerating organic carbon decomposition and carbon dioxide release potential, although it also increases carbon accumulation. [ABSTRACT FROM AUTHOR]

Wetlands comprise unique water storage and conveyance mechanisms that maintain landscape integrity under the sub-humid climate in the Athabasca Oil Sands Area. In addition to their internal function, wetlands support a two-way hydrological connection to adjacent uplands and provide water for downstream water courses. Understanding the role of wetlands as integral parts of surface water (SW)–groundwater (GW) exchange can provide insights into the functioning of the hydrological system as a whole and contribute to thoughtful water management strategies and better coordination of monitoring efforts in the areas affected by oil sands (OS) activities. As such, this study summarizes the current state of hydrological knowledge on the role of wetlands in SW–GW interactions based on studies conducted within the Western Boreal Plains. In particular, the role of wetland soils and their properties in SW–GW interactions, the effects of wetlands on landscape hydrological connectivity and watershed runoff, and features of "wetland–aquifer" and "wetland–open waterbody" interactions were reviewed. Given that alterations of SW–GW interactions in wetlands can occur as a result of anthropogenic disturbances, the coordination of GW, SW, and wetland monitoring efforts and targeting areas where increased SW–GW exchange occurs would be beneficial for the economic and logistical efficiency of the OS monitoring network. [ABSTRACT FROM AUTHOR]

Interstitial water or pore water occupies the space between soil particles and provides "hotspots" and "fluvial networks" for microbial activities in floodplain soil. However, to date, we know very little about the microorganisms living in pore water and how they respond to environmental changes. This study aimed to understand microbial distribution and assemblage in riparian pore waters, and how they respond to water chemistry and redox gradients associated with hydrological processes.We analysed the annual changes of porewater microbial communities from the east and west banks of the White Clay Creek, a site at the Christina River Basin – Critical Zone Observatory, Pennsylvania, USA. Microbial abundances were quantified by epifluorescence microscopy and detailed community structures were characterised by high‐throughput sequencing. Water chemistry and redox gradients were also monitored and recorded, and their interactions with porewater microbiomes were analysed using correlations and multivariate analyses.Abundance of microbial cells increased during summer and late autumn. Wetland porewater microbiomes mainly contained Acidobacteria, Bacteroidetes, Nitrospirae and Proteobacteria, and microbiome structures were easily distinguishable from those in the underlying hyporheic gravel layer. Seasonal dynamics of bacterial community structure in the east and west wetlands were distinct, responding to floodplain topography and associated hydrological/geochemical processes. Iron (Fe)‐cycling bacteria (mainly Gallionellaceae and Rhodoferax spp.) dominated the porewater microbiome, and their relative abundance was significantly higher in the east than the west wetland. Furthermore, Fe‐oxidising bacteria (Gallionellaceae) were negatively correlated with Fe‐reducing bacteria (Rhodoferax spp.) at the east wetland.Microbial abundances (cell density) in pore waters showed similar seasonal patterns across stream banks, but microbial community structure did not. Microbiome assembly in pore water is correlated with water chemistry and redox gradients primarily associated with local hydrological processes.As a consequence of their significance for carbon (C) mineralisation and Fe reduction at terrestrial–aquatic interfaces, microbiomes in riparian pore waters and associated microbial activity play an essential role in C and mineral dynamics. These findings will inform future studies of the response of freshwater ecosystems to hydrological dynamics influenced by global climate change. [ABSTRACT FROM AUTHOR]

The Glenorchy area of northwest Otago consists of a low-relief Holocene fluvial delta complex below glaciated mountains of Otago Schist basement, and has locally elevated arsenic (As) from two geogenic pathways: Mesozoic hydrothermal processes and Holocene shallow groundwater transport. Soils on the delta complex are primitive and contain abundant sand and silt derived from unoxidised schist basement, with background As contents generally <30 mg/kg. Some soils in wetland areas on the delta have naturally elevated (geogenic) arsenic contents that are locally >300 mg/kg on the cm2 scale. Arsenic enrichment has occurred in the upper 30 cm where dissolved As and Fe from low-redox chemical conditions in shallow groundwater has become oxidised, thereby lowering their solubility. Both As and Fe are being mobilised from background sulfide minerals in schist-derived debris, and groundwater As concentrations up to 0.8 mg/L have been recorded. Historic mining of scheelite for tungsten on the surrounding mountains has exposed small volumes (typically tens to hundreds of m3) of arsenopyrite-bearing mine wastes with spot As contents from <500 to >10 000 mg/kg. Water discharging from mine adits have pH∼8 and dissolved As up to 0.3 mg/L, but these waters are rapidly diluted downstream to <0.02 mg/L. [ABSTRACT FROM AUTHOR]