工业工程最新文献

Filter-feeding bivalve aquaculture enhances the transport of particulate organic carbon (POC) to the seafloor through filtration, selective feeding, and biodeposition, thereby altering the sources, fluxes, and reactivity of sedimentary organic carbon (SOC). However, aquaculture-induced organic carbon inputs are characterized by "high input, high reactivity, and high uncertainty". After entering the sediment, a fraction is returned to the water column through microbial remineralization, resuspension, and lateral transport, whereas another fraction is stabilized through rapid burial, mineral protection, and microbial reworking, which is ultimately retained through long-term burial. Whether enhanced POC sedimentation results in a net sedimentary carbon sink therefore depends on the partitioning of newly added organic carbon among remineralization, physical export, transient preservation, and long-term burial. The current debate centers on whether increased POC sedimentation or SOC accumulation in surface sediments can demonstrate a contribution of bivalve aquaculture to sedimentary carbon sequestration. Assessments based solely on sedimentation fluxes or SOC increments may overestimate the carbon-sink effect, whereas an exclusive emphasis on remineralization losses may underestimate the contribution of stabilization and long-term burial. Following the process sequence of "input-remineralization-stabilization and burial", we synthesized the transformation processes and controlling mechanisms of SOC in filter-feeding bivalve aquaculture systems and clarified the conditions under which aquaculture-induced organic carbon inputs could generate a long-term positive increment in SOC burial and thereby constitute a net sedimentary carbon sink. Future studies should strengthen synchronous observations and coupled accounting of these processes across relevant timescales, quantify SOC burial efficiency and its influencing factors among different bivalve species, farming practices, and environmental conditions, and establish a framework for assessing sedimentary carbon sinks in bivalve aquaculture.

Coastal aquaculture ponds are sources of methane (CH₄), which are non-negligible in regional greenhouse gas budgets. However, the seasonal dynamics of CH₄ production and emission in these systems, as well as the driving factors, remain poorly understood. We explored the seasonal variations of soil CH₄ production potential, water gas interface CH₄ emission flux, and related environmental factors in the cultivation pond formed by natural salt marsh wetland reclamation at the mouth of the Minjiang River, by combining in situ field observations and laboratory cultivation experiments. Results showed that soil CH₄ production potential ranged from 8.78 to 60.44 ng·g^-1·d^-1 and water-air interface CH₄ emission flux ranged from 18.58 to 194.74 μmol·m^-2·h^-1, with seasonal coefficients of variation of 65.8% and 79.9%, respectively. Both variables exhibited seasonal dynamics, following the consistent order of summer>autumn>spring>winter. Soil CH₄ emission peaked in summer and autumn. Soil CH₄ production potential was positively correlated with water-air interface CH₄ emission flux in the aquaculture ponds, indicating that methanogenesis in soils was a key factor regulating CH₄ emission across the water-air interface. Random forest analysis identified soil temperature, dissolved organic carbon, microbial biomass carbon, SO₄^2-, and the gene abundances of methanogens and methanotrophs as the primary drivers controlling the seasonal dynamics of CH₄ production and emission. Overall, CH₄ emissions from coastal aquaculture ponds were dominated by a warm-season peak, with substrate supply as the primary driver. Given that feed input is the main source of organic matter and nutrients in aquaculture ponds, it directly determines the available supply of substrates. In the future, emission reduction should focus on optimizing feed utilization efficiency in summer and autumn, achieving a synergistic improvement of CH₄ emission reduction and aquaculture benefits.

Coastal wetlands are unique ecosystems formed by the interaction between land and sea, serving as important ecological barriers supporting sustainable development. They possess high biological productivity, strong ecological resilience, and significant carbon sink functions, but are currently under dual pressures from intense human activities and global climate change. Here, I systematically sorted out the development context and trends of research on coastal wetlands' response to global change. The global research on coastal wetlands has achieved multiple key transformations. At the cognitive level, it has shifted from a die-off prediction of coastal wetlands under climate stress to a resilience cognition that emphasizes active ecological adaptation. In mechanism research, it has expanded from focusing on regional processes to basin-scale coupled intervention. The concept of conservation and restoration has upgraded from "area priority" to "quality orientation". The realization of ecological value has moved from the scientific cognition level to market-oriented practice. These transformations indicate that the research, conservation and restoration of coastal wetlands have entered a new stage of development. Meanwhile, this field still faces core challenges, including insufficient analysis of multi-interface ecological processes and driving mechanisms, imperfect precise simulation and decision support systems, and immature technologies for ecological function improvement. In the future, the research, conservation, and restoration of coastal wetlands should adhere to the principles of land-sea coordination and sustainable development, with the core goals of enhancing ecological resilience, maximizing ecological functions, and promoting the marketization of ecological value. It is necessary to focus on deepening the analysis of multi-interface processes and mechanisms, constructing a precise simulation and decision support system, developing near-natural ecological restoration and synergistic efficiency technologies, improving the ecological product trading system, and building a land-sea coordinated protection pattern to realize the synergistic governance of river basins and coastal zones.

Soil dissolved organic matter (DOM), as a key component of the active organic carbon pool in wetland, is deeply involved in organic carbon migration, microbial transformation, and carbon release, and plays an important role in wetland carbon turnover and carbon pool stability. However, the spatial distribution and dominant controlling factors of wetland soil DOM at large geographic scales remain poorly understood. In this study, we selected 57 freshwater wetland sites spanning approximately 4000 km from north to south in eastern China. Using spectroscopic methods, we investigated the spatial distribution of soil DOM in eastern freshwater wetlands, and identified the key driving factors by integrating climatic, vegetation, soil physicochemical, and microbial community variables. The results showed that, along the north-to-south climatic gradient, the quantity and humification degree of wetland soil DOM showed a significant decreasing trend, whereas biogenic characteristics increased signifi-cantly. In terms of component composition, humic-like components dominated in colder regions, whereas protein-like components accounted for a higher proportion in warmer regions. Across different wetland types, peatlands had significantly higher soil DOM quantity than other wetland types, with a relatively high proportion of humic-like components. In contrast, lakeshore and riparian wetlands showed stronger biogenic characteristics and higher proportions of protein-like components, indicating that the specific hydrothermal environments and carbon input-output pathways of different wetland types may jointly regulate DOM accumulation and component differentiation. Results of hierarchical partitioning analysis further showed that DOM quantity, characterized by dissolved organic carbon, was mainly influenced by soil resource conditions, such as total carbon, total nitrogen, and available nitrogen, with a relative contribution of 61.5%. DOM humification degree and biogenic characteristics were mainly driven by bacterial communities and climate, with relative contributions of 34.4% and 35.7%, respectively. Spatial variation in DOM component composition was mainly regulated by climate, with a relative contribution of 64.0%. Overall, the spatial pattern of soil DOM in freshwater wetlands of eastern China is jointly shaped by the synergistic effects of climate and wetland type, while DOM accumulation, optical characteristics, and component composition are driven by different environmental constraints and ecological processes. This study could provide basic data and theoretical reference for evaluating the stability of active carbon pools in wetlands under climate change.

Coastal wetlands are biogeochemical hotspots for the global sulfur cycle. Driven by the combined influences of hydrodynamic processes, multiple material inputs, and pronounced redox gradients, sulfur undergoes complex valence-state variations and speciation transformations in coastal wetlands. We systematically summarize research advances on sulfur cycling in coastal wetlands in nearly four decades, with a focus on the major forms and classification of inorganic sulfur pools. We discuss the impacts and underlying mechanisms of microorganisms, plants, key physicochemical environmental factors, and anthropogenic disturbances on inorganic sulfur transformation and mobility. We further examine the role of sulfur cycling in mediating carbon source-sink processes in coastal wetlands. Firstly, sulfate reduction regulates sedimentary carbon transformation by mediating anaerobic organic matter mineralization. Secondly, organic matter sulfurization, sulfur oxidation-driven chemolithoautotrophic dark carbon fixation, and iron-sulfur mineral formation and associated mineral protection of organic carbon collectively contri-bute to carbon stabilization and burial. Thirdly, sulfur cycling regulates coastal wetland greenhouse gas budgets by modulating the production and emission processes of CO₂ and CH₄. Future research should focus on the sulfur cycle response mechanisms under global change, multi-element coupling processes, and the construction of sulfur-carbon cycle models. This review would provide a scientific basis for enhancing ecosystem management and blue carbon sequestration in coastal wetlands and supporting the restoration and maintenance of ecosystem services under ongoing global climate change.

To identify the spatial variations in the relationship between dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in global lakes and the major driving factors, we constructed a "hydrological-nutrient" scenario analysis framework using methods including MissForest imputation, classification and regression trees (CART), and generalized additive models (GAMs). Based on global lake DOC and DIC observational data, we compared the correlations between DOC and DIC under different environmental conditions and analyzed their driving factors. The results showed that the CART model identified two primary environmental segmentation points: an annual rainfall of approximately 457 mm and a total nitrogen concentration of about 1.7 mg·L^-1. Global lakes could thus be classified into four scenarios: humid-high nitrogen, humid-low nitrogen, arid-high nitrogen, and arid-low nitrogen. There were significant differences in the relationship between DOC and DIC across these scenarios. In humid-high nitrogen lakes, a weak positive correlation was found, with water temperature near 17.5 ℃ exhibiting nonlinear response characteristics, suggesting that biological processes and water stratification may jointly influence the DOC-DIC relationship under eutrophic conditions. In humid-low nitrogen lakes, the correlation was near zero, likely due to DOC being primarily influenced by soil organic carbon inputs from the watershed, while DIC was more controlled by groundwater recharge, rock weathering, and carbonate equilibrium processes. In arid-high nitrogen lakes, DOC and DIC showed a significant positive correlation, indicating that evaporation concentration and synchronous solute accumulation may be key drivers of their co-varying trends. In arid-low nitrogen lakes, the correlation was weaker, with a response peak in chlorophyll-a concentration near 15 μg·L^-1, suggesting that lower primary productivity may exert phased effects on the dissolved carbon component relationship. Overall, conductivity, pH, water temperature, soil organic carbon, rainfall, and chlorophyll-a were key factors driving the DOC-DIC relationship across different scenarios. The DOC-DIC relationship in global lakes did not exhibit stable synchronous changes but instead demonstrated clear scenario dependence and nonlinear characteristics, necessitating comprehensive analysis in conjunction with hydrological conditions, nutrient status, and lake physicochemical environments.

Wetland soil organic carbon comprises organic fractions that differ in biological origin, decomposition stage, and stabilization status. The preservation of plant-derived residue carbon and the accumulation of microbial necromass carbon represent two important pathways for SOC formation and stabilization in wetlands. Lignin phenols and amino sugars are commonly used to characterize lignin-derived plant residue components and estimate microbial necromass carbon, respectively. We synthesized the contrasting patterns of these two source-related residue carbon components across different wetland types and clarified the major drivers. Their contents vary substantially among wetland types, but the differences cannot be attributed to any single environmental factor. Instead, they emerge from the combined effects of plant inputs, microbial processing, decomposition and mineralization losses, and physicochemical protection. Under low-temperature, persistently anoxic, and strongly peat-forming conditions, the decomposition of plant residues is constrained, thereby promoting their preservation. Meanwhile, continuous plant inputs provide substrates for microbial assimilation and subsequent necromass formation. Water-table fluctuations, alternating redox conditions, sedimentation, and anthropogenic management can modify these processes and thereby regulate the relative contributions of plant-derived residue carbon and microbial necromass carbon. Future research should integrate multiple biomarkers with complementary multi-proxy approaches to elucidate the formation, transformation, and stabilization pathways of biologically derived residue carbon in wetlands, thereby advancing our understanding of wetland carbon pool formation and its responses and feedbacks to climate change.

We examined the changes in soil nitrous oxide (N₂O) emission from meadow communities with different grazing exclusion periods (1, 4, and 7 years) in Napahai Wetland. We measured soil N₂O flux using the static chamber-gas chromatography method, combined with the logarithmic response ratio (RR_i) to investigate its spatiotemporal variations, and analyzed the impact mechanisms of grazing exclusion duration on N₂O emissions. The results showed that grazing exclusion significantly promoted soil N₂O emissions. The RR_i value increased with the extension of grazing exclusion duration, with the RR_ivalue under the 7-year grazing exclusion treatment being 5.6 times that of the 1-year treatment. Compared with the free grazing control, grazing exclusion significantly increased aboveground and underground biomass (increased by 42.8%-611.9%), and decreased the Margalef, Shannon, Pielou, and Simpson indices of plants (decreased by 15.1%-59.3%). Grazing exclusion significantly increased soil water content, pH, organic matter, total nitrogen, available nitrogen, and microbial biomass nitrogen, and reduced soil bulk density. Soil temperature and inorganic nitrogen (NH₄⁺-N, NO₃^--N) decreased first and then increased with the increase of grazing exclusion duration. The RR_i values of plant biomass, soil water content, pH, organic matter, total nitrogen, available nitrogen, and microbial biomass nitrogen all peaked under the 7-year grazing exclusion treatment (increased by 7.5%-352.2%). Soil N₂O emission flux was significantly positively correlated with aboveground biomass, soil water content, pH, and carbon and nitrogen content, and significantly negatively correlated with soil bulk density and plant diversity. The structural equation model explained 89.2% of the total variation of N₂O emissions, with aboveground biomass (direct effect: 87.5%), soil water content (76.5%), soil nitrogen content (83.4%), and soil pH (48.7%) as the main positive driving factors. In summary, short-term gra-zing exclusion significantly increased soil N₂O emissions in the Napahai meadow wetland by increasing aboveground biomass, soil moisture, nitrogen availability, and soil aeration (reducing bulk density), and such effect continued to increase with the extension of grazing exclusion duration.

Wetlands support rich biodiversity and provide unique habitat functions, playing a critical role in maintaining regional biodiversity and ecological processes. Evaluating the stability of habitat function is fundamental for identifying the quality and health status of wetlands and for guiding wetland conservation, restoration, and sustainable management. However, available habitat function assessments have mainly focused on individual indicators, lacking systematic multidimensional indicator frameworks and integrated evaluation approaches. To address this knowledge gap, we proposed a systematic methodological framework for assessing the stability of wetland habitat function. First, an evaluation indicator system comprising 11 sub-criteria layers and 43 candidate indicators was developed from four criterion layers, including environmental factors, biological composition, landscape patterns, and stress disturbances and conservation management. According to the temporal characteristics, those indicators were further classified into time-series ones and structural-state ones. Based on the constructed annual habitat function index (HFI) time series, stability was quantified from three dimensions: variability, resistance, and recovery. Specifically, the coefficient of variation was used to characterize long-term fluctuations. The relative change in HFI before and after disturbance was used to quantify resistance. Recovery rate, recovery magnitude, and recovery time were employed to describe recovery capacity. Furthermore, two approaches, including dimension-specific representation and a comprehensive habitat function stability index (HFSI), were established for integrated stability assessment. This framework systematically incorporated ecosystem stability theory into wetland habitat function evaluation, providing a quantitative basis for identifying wetland degradation, implementing conservation and restoration interventions, and supporting adaptive management.

Marshes are characterized by strong organic carbon accumulation capacity and important carbon sink functions. However, large-scale marshland reclamation for cropland can lead to substantial depletion of marsh soil carbon pools and impairment of soil organic carbon (SOC) stability. Iron minerals are important carriers of SOC and can form carbon-iron complexes (Fe-OC) through adsorption and co-precipitation, thereby contributing to SOC retention. Here, we summarize the effects of reclamation on SOC content and fractions in marsh soils. We further review how iron mineral forms, Fe-OC association mechanisms, organic carbon molecular composition, microbial processes, and environmental factors regulate the carbon-sequestration function of iron minerals, and evaluate the effects of reclamation on this function in marsh soils. We summarize current knowledge gaps and highlight the need to clarify how reclamation-induced changes in carbon sources affect the stability and thresholds of iron mineral-associated carbon sequestration, to elucidate the succession of Fe-reducing microbial communities and their roles in regulating iron mineral carbon sequestration, and to develop sustainable carbon management strategies for reclaimed marsh soils. This review would provid a better understanding of the mechanisms by which reclamation affects the stability of marsh soil carbon pools and provides a scientific basis for sustainable marsh management.