• Soil physicochemical traits and microbes characterized along a salinity gradient • Salinity, sulfur, and iron shape microbial structure across wetlands • Sulfur-reducing bacteria dominate highly saline soils • Salinization lowers CH 4 but increases CO 2 emissions Coastal wetlands play a critical role in carbon sequestration, biogeochemical cycling, and ecosystem stability. These habitats support diverse microbial communities that regulate organic matter decomposition and greenhouse gas fluxes, influencing climate-related feedback mechanisms. However, rising sea levels and saltwater intrusion may disrupt microbial processes, particularly those associated with the sulfur cycle and methane dynamics. Here, we characterize soil physicochemical properties and microbial communities along a salinity gradient in three temperate coastal wetlands to assess the impact of salinity on organic matter decomposition and greenhouse gas emissions. Using full-length Oxford Nanopore MinION 16S rRNA amplicon sequencing, we analyzed microbial communities across freshwater, brackish, and saline wetland soils. Our results indicate that sulfur-reducing bacteria dominate salinized sites, while brackish environments are characterized by obligate anaerobic taxa involved in sulfate reduction, fatty acid degradation, and denitrification. These microbial assemblages contribute to lower CH 4 emissions but increased CO 2 fluxes in the brackish areas, highlighting key microbial-mediated trade-offs in wetland carbon cycling. By integrating microbial diversity, and metabolic functions with soil geochemistry, this site-specific but ecologically meaningful case study improves our understanding of microbe-soil interactions in temperate wetland ecosystems facing increased salinization due to climate change.

To study the effect of drainage intensity on GHG emissions and N drainage losses in cool-humid Norway, we established drainage systems with 6 and 12 m drain spacing in a previously undrained sandy loam (Mollic gleysol) collecting data in the years 2014–2016. After sowing a mixed grass ley, subsurface drainage was larger (1271 versus 699 mm) and mean ground water table (GWT) lower (102 versus 79 cm) with 6 than with 12 m drain spacing. Water filled pore space (WFPS) remained high throughout most of the year (> 80 %). It was highest in 12 m drain spacing, but shortly after fertilizations no differences between the two drainage systems were found. N 2 O emissions after fertilization were larger in the 12 m system than in the 6 m system. Cumulative N 2 O emissions in the 6 and 12 m system were 4.0 versus 2.5 kg N ha −2 yr −1 . N leaching for the entire observation period (29 months) was larger in the 6 m (42 kg ha −1 ) than the 12 m (19 kg ha −1 ) system . Grass yields, plant N-recovery and fertilizer N use efficiency was larger with 6 than 12 m. The mean N 2 O emission factor was significantly higher with 6 than with 12 m drain spacing (1.4 versus 0.8 % N 2 O-N of N applied). The 6 m system acted as a net sink for CH 4 , whereas the 12 m system was a net CH 4 source and had a higher climate forcing than the 12 m system (1390 versus 1110 g CO 2 eq. m −2 yr −1 ), but scaled for grass dry matter yield the climate forcing was similar. We conclude that larger N 2 O emissions with 6 m drain spacing were likely due to a combination of less complete denitrification and a naturally higher SOM content at this site, releasing extra mineral N. Our study can therefore not confirm that increased drainage intensity intrinsically reduces N 2 O emissions from crop production in cool-humid climates. • Reducing drain spacing from 12 to 6 m did not reduce N 2 O emissions. • Soil variation has a large effect on the impact of drain spacing on N 2 O emission. • Reduced drain spacing increased subsurface drainage and N-leaching. • Soil conditions were more reductive with 12 than 6 m drain spacing. • Reduced drain spacing changed CH 4 fluxes from net emission to net uptake.

Vegetated coastal lagoons provide carbon dioxide (CO2) uptake and are often inventoried as blue carbon (C) sinks. We measured greenhouse gas (GHG) fluxes, CO2, methane (CH4), and nitrous oxide (N2O), at the water-air interface in dominant habitats including oyster aquaculture, eelgrass, and bare sediments of two temperate, eutrophic coastal lagoonal systems in Rhode Island (RI), and estimated sediment C accumulation in eelgrass habitats. We examined whether system GHG emissions at the water-air interface offset estimated eelgrass sediment C accumulation. Although highly variable, we often measured net CO2 and CH4 emissions from eelgrass and other habitats, which offset some or all of the estimated C accumulation in eelgrass sediments. At Potter Pond the monthly (May - October 2023) mean CO2 equivalent (CO2e) over a 100y horizon at the bare habitat (-0.0071 ± 0.63 ug m-2 s-1) was a net sink, while the mean CO2e-100y at eelgrass (4.74 ± 0.91 ug m-2 s-1) and oyster (2.30 ± 0.71 ug m-2 s-1) habitats were net sources. At Pt. Judith Pond the mean CO2e-100y across months and among habitats ranged from 2.49 ug m-2 s-1 at the oyster habitat to 5.08 ug m-2 s-1 at the eelgrass habitat. High CO2 and CH4 emissions might be attributed to the abundance of labile macroalgae, which decomposes rapidly, and to mineralization of legacy C in sediments associated with declining eelgrass. GHG emissions in eutrophic, vegetated lagoons might offset sediment C accumulation and cause an overestimation of blue C sinks.

Statistical and culture-based models propose that environmental disturbances reshape competitive interactions among functionally redundant microbial taxa. However, the mechanisms driving these changes and their impact on biogeochemical processes remain largely untested in soil, owing to the challenge of linking functions to specific taxa in highly diverse and functionally complex soil microbiomes. Here, we simulated environmental disturbance in microcosms containing organic carbon-rich or sandy soils. Using bacterial and archaeal nitrifiers, a functionally tractable microbial guild, we examined how disturbance restructures competition among diverse microbial taxa within this guild. In both soils ammonia-oxidizing archaea (AOA) predominated numerically and functionally under steady climax conditions. Following disturbance, ammonia-oxidizing bacteria (AOB) and complete ammonia oxidizers (comammox) rapidly gained a growth-related competitive advantage, likely due to increased per-cell ammonium availability supporting their intrinsic high growth rates. AOB recolonization was essential for full post-disturbance nitrogen turnover, resulting in elevated nitrification rates and increased nitrous oxide emissions. Nitrification rate did not fully recover when AOB were inhibited. In contrast, AOA and comammox played a dispensable role in recovering post-disturbance nitrification, limited by slower growth and lower per-cell activity, respectively. Competitive regrowth ability of microbial species showed a tradeoff with pre-disturbance abundance, highlighting the enhanced post-disturbance role of rare-abundance AOA, in addition to AOB phylotypes. Our findings demonstrate that bacterial and archaeal nitrifiers constitute a continuous spectrum between r- and K-strategists. Disturbance reshapes competition through differential growth and activity traits among functionally redundant taxa, favoring AOB and thereby transforming community assembly while intensifying nutrient cycling and greenhouse gas fluxes.

Treated sewage discharge mitigates net greenhouse gas emissions from polluted urban rivers.

Agricultural and urban land use intensifies riverine GHG emissions across continents.

Dataset of greenhouse gas fluxes and soil properties from a biochar application frequency and dosage experiment in an upland agroecosystem in Guizhou, China (2020-2023).

Wirelessly controlled modular automatic chambers for greenhouse gas flux monitoring in natural and agricultural ecosystems.

Soil moisture and temperature effects on seasonal and diurnal fluxes of methane and other greenhouse gases from a temperate woodland

Threshold responses of soil greenhouse gas fluxes to rock fragment content in boreal forest soils

Optimal production strategies for balancing yield enhancement, carbon sequestration, and soil greenhouse gas flux regulation in Chinese maize systems under straw return and organic fertilizer application

Agrivoltaic shading reduces soil greenhouse gas fluxes in a semi-arid vineyard

Microbial and environmental regulation of greenhouse gas fluxes from marine ranching sediments under seasonal hypoxia.

This study aims to measure Greenhouse Gas (GHG) emission fluxes at the soil-air and water-air interfaces in urban wetlands on the Qinghai-Tibet Plateau and identify the primary controlling factors. The objective is to elucidate the key drivers of carbon and nitrogen processes at different interface levels in wetlands within high-altitude urban settings, thereby providing a scientific basis for accurately estimating their contribution to greenhouse gas emissions. In the wetlands of Xining City, with the exception of soil pH, bulk density, and moisture content (which showed no significant change over time), all other soil physicochemical properties differed significantly among the three wetlands and among the sampling periods (p < 0.05). Soil moisture content was less affected by variations across different wetlands and over time, and differences in soil physicochemical properties among different wetlands were small (p > 0.05). Significant differences were observed in the spatiotemporal variations in the physicochemical properties of water bodies in Xining's wetlands (p < 0.05), although water pH and total organic carbon (TOC) were less affected by the interaction between different wetlands and time periods. There were no significant differences in the bulk density and moisture content of wetland sediments in Xining over time (p > 0.05), while all other physicochemical indicators of sediments showed significant differences (p < 0.05). The physicochemical properties of sediments were influenced by both different wetland types and different time periods. GHG fluxes at the water-air interface in Xining wetlands were greater than those at the soil-air interface; overall, GHG emissions from both interfaces acted as "sources." Seasonal variations in wetland GHG emissions were pronounced, with emission peaks occurring from June to August. The study found that the primary soil factor influencing GHG emissions at the soil-air interface was total phosphorus (TP), while the primary sediment factors affecting emissions at the water-air interface were TP and nitrate nitrogen (NO3--N), and the primary water factor was TOC. The interannual cumulative emissions from both interfaces in the wetland totaled 705.88 g·m-2. GHG emissions from the soil-air and water-air interfaces contributed 47.88% and 52.12%, respectively, to the global warming potential (GWP) of the wetland, while methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) contributed 32.55%, 62.33%, and 5.12%, respectively, to the GWP. Investigating the GHG emission patterns in Xining's wetlands and identifying the primary factors influencing these emissions provides a scientific basis for the protection and restoration of these wetlands. This is of great significance for safeguarding the ecological security of Xining's wetlands as well as the overall ecological security of high-altitude wetlands.

Contrasting greenhouse gas fluxes in a city river-lake continuum: CH4 diffusive emissions offset by N2O sequestration.

Organic compounds with a negative nominal oxidation state of carbon (NOSC) are thermodynamically recalcitrant in anaerobic ecosystems, but few studies have measured the influence of NOSC on carbon degradation rates, gaseous product yields, or microbiome composition. We amended anaerobic rice paddy sediment microcosms with water-soluble monomeric organic carbon compounds varying in NOSC. Consistent with thermodynamic and stoichiometric predictions, negative NOSC compounds are catabolized more slowly but produce more methane per mole of carbon. Negative NOSC microbiomes have higher alpha diversity, more syntrophs and methanogens, and fewer fermentative bacteria. Strikingly, fermentative bacterial taxa display genomically encoded NOSC catabolic preferences both in the lab and field. Negative NOSC-preferring fermenters have longer predicted doubling times, consistent with the thermodynamic recalcitrance of their preferred substrates. We propose that microbial NOSC catabolic preferences may reflect the thermodynamic niche of microorganisms and we anticipate that extending research on microbial catabolic preferences to a greater variety of organic carbon substrates and diverse microbiomes will improve our understanding of microbial carbon cycling and trait evolution.

Agricultural residues represent an abundant and underutilized resource that can be redirected from disposal pathways toward value-added applications such as composting, mulching, bioenergy, land amendment, and bioplastics. This chapter examines these pathways through the perspective of life cycle assessment (LCA), highlighting how agricultural residues can contribute to waste reduction, soil improvement, greenhouse gas mitigation, and circular resource use. Across the reviewed case studies, environmental outcomes are shown to depend not only on the residue itself, but also on the selected conversion pathway, management practice, system boundary, and local implementation context. Composting and mulching can reduce environmental burdens, although benefits remain sensitive to process modifications, additive use, and field conditions. Energy recovery from residues can offer substantial gains when carbon-intensive reference systems are displaced, but performance varies with logistics and conversion efficiency. Land application may improve soil quality and carbon retention while also shifting greenhouse gas fluxes depending on amendment type and site conditions. Likewise, residue-derived bioplastics can lower impacts relative to fossil-based plastics under favorable feedstock and end-of-life scenarios, but these benefits are not universal. Overall, the chapter shows that LCA is a valuable tool for comparing residue management options while also emphasizing the need for integrated assessment frameworks that account for environmental, technical, and implementation-related factors when selecting sustainable valorization strategies.

Optimizing water-nitrogen-biochar (W-N-B) management is essential for achieving sustainable greenhouse tomato production under climate change. This study assessed long-term changes in soil organic carbon (SOC), greenhouse gas fluxes, and tomato yield under three Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5) during 2025-2100 and evaluated trade-offs among carbon mitigation, productivity, and resource use efficiency. The results showed that biochar application consistently increased tomato yield and SOC while reducing CO2 and N2O emissions, whereas irrigation and nitrogen input primarily influenced yield formation and N2O emissions. Among the three climate scenarios, SSP1-2.6 produced the greatest cobenefits, with yield increasing by 4.16%, SOC rising by 0.73%, and global warming potential decreasing by 18.6%. The optimal W-N-B management strategies were identified as W1N3B3 under SSP1-2.6, W2N2B2 under SSP2-4.5, and W2N3B3 under SSP5-8.5. These findings provide scientific support for developing high-yield and low-carbon greenhouse agriculture in arid regions of Northwest China.

The online version contains supplementary material available at 10.1007/s42773-026-00610-2.

Mangroves are widely recognized as climate-relevant ecosystems, yet the extent to which soils are incorporated into climate mitigation research remains unclear. This study conducted a hierarchical bibliometric analysis (Scopus, 1950–2025) across five progressively restrictive search levels, moving from general mangrove research (Level 1) to studies incorporating climate change (Level 2), mitigation (Level 3), and soil-related processes (Levels 4 and 5). Results show that although 30,084 articles addressed mangrove broadly, only 25 articles (0.08%) explicitly linked mangrove soils to climate change mitigation, with the majority published after the emergence of the blue carbon concept in 2009. Keyword evolution and network analyses indicate a shift from descriptive ecological themes (e.g., distribution and vegetation dynamics) toward carbon-related and soil-associated processes (e.g., blue carbon, carbon sequestration, soil organic carbon), particularly after the late 2000s, accompanied by gradual diversification into Environmental Science, Earth and Planetary Sciences, and chemistry-related domains associated with soil processes and mitigation mechanisms. Despite these conceptual advances, keyword analysis shows that mitigation-related studies (Levels 3 and 5) remain largely focused on terms such as “mangroves” (336 occurrences), “carbon sequestration” (187), “organic carbon” (82), and “carbon storage” (62), with limited representation of mechanistic soil processes (e.g., redox-processes, soil greenhouse gas fluxes, carbon–iron–sulfur coupled dynamic) in climate mitigation frameworks. Expanding this integration represents a key scientific frontier for improving the robustness and scalability of mangrove-based climate mitigation strategies.