环境科学与生态学最新文献

{"title":"Advantages of the E-CMRSET model in unveiling evapotranspiration water consumption patterns in the inland river basin","authors":"Hongxin Liu ,&nbsp;Aihua Long ,&nbsp;Yongmin Yang ,&nbsp;Jiawen Yu","doi":"10.1016/j.jenvman.2025.125426","DOIUrl":"10.1016/j.jenvman.2025.125426","url":null,"abstract":"<div><div>Vegetation serves as a critical link between the hydrosphere, biosphere, and atmosphere, playing a vital role in the terrestrial water cycle. In arid and semi-arid regions, soil moisture stands out as the primary factor regulating evapotranspiration. Over the past two decades, the comprehensive management project in the Tarim River Basin (TRB, a typical case of an inland river basin in an arid area) has induced substantial changes in the underlying surface, marked by a significant increase in vegetation cover. This shift has the potential to escalate evapotranspiration, intensifying water-related challenges in the region. To assess landscape-scale evapotranspiration in TRB, we employed the enhanced CSIRO MODIS Reflectance-based Scaling EvapoTranspiration model (E-CMRSET), incorporating vegetation changes and soil moisture dynamics as new components. Our analysis delved into evapotranspiration variations across different vegetation types within the TRB. Subsequently, we evaluated the impact of these vegetation changes on regional-scale water consumption patterns. Comparative validation results highlight the superior overall performance of the E-CMRSET model in the TRB when compared to the original CMRSET model, ERA5-Land, PMLV2, EB-ET, and MOD16A2. Vegetation-induced alterations have significantly reshaped the spatiotemporal pattern of evapotranspiration. Notably, the expansion of farmland emerges as the primary contributor to the heightened basin-wide evapotranspiration. Areas surrounding artificial oases witness flourishing vegetation, resulting in a noteworthy increase in water consumption. In contrast, regions distant from human activity zones experience substantial reduction in vegetation, exacerbating encroachments on ecological water usage. Our research contributes valuable insights that can inform models and decision-making processes related to evapotranspiration in arid and semi-arid regions.</div></div>","PeriodicalId":356,"journal":{"name":"Journal of Environmental Management","volume":"384 ","pages":"Article 125426"},"PeriodicalIF":8.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the role of bamboo species in the restoration of heavy metal-contaminated soil","authors":"Qin Cao ,&nbsp;Guang-Qian Gou ,&nbsp;Zhao-Xia Dai ,&nbsp;Ai-Juan Tan ,&nbsp;Gui-Li Yang","doi":"10.1016/j.jenvman.2025.125565","DOIUrl":"10.1016/j.jenvman.2025.125565","url":null,"abstract":"<div><div>Heavy metal contamination in the soil has become more serious due to the rapid development of the economy. P<strong>hytoremediation</strong> has evoked widespread curiosity in recent years due to its advantages in terms of being environmentally friendly and sustainable. However, there are few reports on the application of bamboo species in the field of phytoremediation, and a comprehensive overview of their potential for restoring contaminated soil by removing heavy metals is lacking. This paper incorporates existing research on bamboo species for the remediation of heavy metal-contaminated soils. It meticulously debates the physiological responses exhibited by bamboo species to heavy metal stress, encompassing growth and development responses, photosynthetic responses, and antioxidant system responses, among others. Furthermore, it elaborates on the capacity of bamboo for heavy metal accumulation and translocation, as well as their remarkable tolerance and detoxification mechanisms. This comprehensive analysis sheds light on the intricate interactions between bamboo and contaminated soil environments. Additionally, the paper summarizes various strategies for the remediation of heavy metal contamination using bamboo species. This review facilitates a more thorough exploration of the potential applications of bamboo species in the remediation of heavy metal-contaminated soils, offering a novel approach for soil environmental restoration.</div></div>","PeriodicalId":356,"journal":{"name":"Journal of Environmental Management","volume":"384 ","pages":"Article 125565"},"PeriodicalIF":8.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial predictive modeling of soil organic carbon stocks in Norwegian forests","authors":"Andreas Hagenbo ,&nbsp;Lise Dalsgaard ,&nbsp;Marius Hauglin ,&nbsp;Stephanie Eisner ,&nbsp;Line Tau Strand ,&nbsp;O. Janne Kjønaas","doi":"10.1016/j.scitotenv.2025.179451","DOIUrl":"10.1016/j.scitotenv.2025.179451","url":null,"abstract":"<div><div>Boreal forest soils are a critical terrestrial carbon (C) reservoir, with soil organic carbon (SOC) stocks playing a key role in global C cycling. In this study, we generated high-resolution (16 m) spatial predictions of SOC stocks in Norwegian forests for three depth intervals: (1) soil surface down to 100 cm depth, (2) forest floor (LFH layer), and (3) 0–30 cm into the mineral soil.</div><div>Our predictions were based on legacy soil data collected between 1988 and 1992 from a subset (<em>n</em> = 1014) of National Forest Inventory plots. We used boosted regression tree models to generate SOC estimates, incorporating environmental predictors such as land cover, site moisture, climate, and remote sensing data. Based on the resulting maps, we estimate total SOC stocks of 1.57–1.87 Pg C down to 100 cm, with 0.55–0.66 Pg C stored in the LFH layer and 0.68–0.80 Pg C in the upper mineral soil. These correspond to average SOC densities of 15.3, 5.4, and 6.6 kg C m⁻², respectively.</div><div>We compared the predictive performance of these models with another set, supplemented by soil chemistry variables. These models showed higher predictive performance (<em>R</em>^<em>2</em> = 0.65–0.71) than those used for mapping (<em>R</em>^<em>2</em> = 0.44–0.58), suggesting that the mapping models did not fully capture environmental variability influencing SOC stock distributions. Within the spatial predictive models, Sentinel-2 Normalized Difference Vegetation Index, depth to water table, and slope contributed strongly, while soil nitrogen and manganese concentrations had major roles in models incorporating soil chemistry.</div><div>Prediction uncertainties were related to soil depth, soil types, and geographical regions, and we compared the spatial prediction against external SOC data. The generated maps of this offer a valuable starting point for identifying forest areas in Norway where SOC may be vulnerable to climate warming and management-related disturbances, with implications for soil CO₂ emissions.</div></div>","PeriodicalId":422,"journal":{"name":"Science of the Total Environment","volume":"980 ","pages":"Article 179451"},"PeriodicalIF":8.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of cadmium exposure on breast cancer risk: Exploring dose-response relationships and mediating effects","authors":"Yongbin Lu ,&nbsp;Yongxia Dang ,&nbsp;Yilin Chen ,&nbsp;Yizhuo Chen ,&nbsp;Xu Hui ,&nbsp;Xiaonan Li ,&nbsp;Xin Fan ,&nbsp;Jingru Yang ,&nbsp;Xiaoling Ling ,&nbsp;Li Ma ,&nbsp;Zhiyuan Cheng ,&nbsp;Kehu Yang","doi":"10.1016/j.ecoenv.2025.118247","DOIUrl":"10.1016/j.ecoenv.2025.118247","url":null,"abstract":"<div><div>Cadmium (Cd), an endocrine disruptor, has been linked to hormone-related cancers, including breast cancer (BC). However, previous studies investigating the association between Cd exposure and BC risk have yielded inconsistent results, and the effects of Cd on BC subtypes remain poorly understood. We employed logistic regression and restricted cubic splines (RCS) to examine the relationship between Cd exposure and BC. A meta-analysis was subsequently conducted to validate the association between Cd exposure and BC. Lastly, mediation analysis was applied to explore the underlying mechanisms linking Cd exposure to BC. Data from 5954 participants in the National Health and Nutrition Examination Survey (1999–2020) were analyzed. Elevated Cd levels in the fourth quartile were significantly associated with an increased BC risk (odds ratio (OR) = 3.74, 95 % confidence interval (CI): 1.45 - 9.62, P_trend = 0.019), compared to the first quartile group. A linear dose-response relationship was seen between urinary Cd levels and BC risk (P_non-linear = 0.532), with BC risk increasing 317 % (OR = 3.17, 95 % CI: 1.93 - 5.20, P_trend &lt; 0.001) for 1 μg/g creatinine increases in urinary Cd levels. The meta-analysis, which included 20 eligible studies, further observed a possible link between Cd exposure and BC risk (relative risk (RR) = 1.17, 95 % CI: 1.06 - 1.29, I² = 83 %), particularly in estrogen receptor-positive (ER⁺) subtypes (RR = 1.08, 95 % CI: 1.01 - 1.16, I² = 70 %). Mediation analysis further revealed that glycated hemoglobin (HbA1c) mediated 9.09 % of the Cd-BC risk association. In conclusion, the study results suggest a potential association between Cd levels and an increased BC risk, particularly in ER⁺ subtypes. Mechanistically, HbA1c was identified as a mediator in this association. These findings underscore the complex interplay between Cd exposure and metabolic dysregulation in the development of BC, highlighting the potential role of HbA1c in modulating BC risk among individuals exposed to Cd.</div></div>","PeriodicalId":303,"journal":{"name":"Ecotoxicology and Environmental Safety","volume":"297 ","pages":"Article 118247"},"PeriodicalIF":6.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace DNA from kill sites identifies individual predators","authors":"Himanshu Chhattani ,&nbsp;Abishek Harihar ,&nbsp;Rounak Dean ,&nbsp;Ajay Yadav ,&nbsp;Kaushal Patel ,&nbsp;Divyashree Rana ,&nbsp;Awadhesh Pandit ,&nbsp;Sanjay Kumar Shukla ,&nbsp;Vincent Rahim ,&nbsp;Uma Ramakrishnan","doi":"10.1016/j.biocon.2025.111117","DOIUrl":"10.1016/j.biocon.2025.111117","url":null,"abstract":"<div><div>Predation ecology and evidence-based conflict management strategies require reliable and accurate identification of individual predators. Identifying predators is, however, complex, as they are secretive and individual identification is difficult. Trace DNA that predators leave behind at kill sites might provide an effective strategy to identify them but remains poorly assessed. We use non-invasive genetic samples from kill sites to assess their utility for predator identification. We systematically investigated 198 livestock kills in two of Central India's critical source tiger populations: Kanha and Bandhavgarh Tiger Reserves. We collected 342 saliva, 33 scat and 395 shed hair samples as potential sources of predator DNA. Individual tigers were identified using up to 123 SNP markers. All sample types were highly successful (&gt;95 %) in identifying tigers. Individual tigers were identified at 85 % of all kill sites using at least one sample. Shed hair samples were most effective for individual identification, followed by saliva and scat. Sample type and sampling season were the primary determinants of the number of SNPs typed per sample and individual identification success. Based on the collection site and type of sample in identification, we classified species and individuals into three categories: true predator (high confidence as predator), circumstantial predator (medium confidence) and predator uncertain (low confidence). Individuals were classified as a true predator at 72 sites, circumstantial predator at 34 sites, and predator uncertain at 49 sites. We suggest that when paired with systematic kill site investigation and sample collection, these methods can be effectively used to understand predation ecology better and facilitate evidence-based conflict management.</div></div>","PeriodicalId":55375,"journal":{"name":"Biological Conservation","volume":"307 ","pages":"Article 111117"},"PeriodicalIF":4.9,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of industrial waste composition for eco-cement production using machine learning with meta-heuristic method","authors":"Wei Luo ,&nbsp;Longming Liu ,&nbsp;Jingping Hu ,&nbsp;Huijie Hou ,&nbsp;Hongyun Hu ,&nbsp;Jiakuan Yang","doi":"10.1016/j.resconrec.2025.108328","DOIUrl":"10.1016/j.resconrec.2025.108328","url":null,"abstract":"<div><div>Industrial solid waste utilization in ecological cement production reduces carbon emissions and resource consumption. However, waste composition variability challenges product consistency, hindering widespread implementation. This study presents a novel artificial intelligence driven optimization framework that combines triple back-propagation neural network (BPNN), non-dominated sorting genetic algorithm-II (NSGA-II) and super-efficiency data envelopment analysis (SE-DEA), to optimize raw material proportions. The triple BPNN architecture, which separately models raw meal grinding, clinker calcination, and clinker homogenization, demonstrates superior prediction accuracy. By integrating SE-DEA within NSGA-II, the algorithm achieves balanced optimization across multiple performance metrics. Cement produced using this optimization framework demonstrates improved long-term mechanical properties, with 28-day compressive strength ranking in the top 4.11 % and 28-day flexural strength in the top 7.41 % of the historical production data from the same facility. The proposed framework exhibits significant potential for the development and promotion of ecological cement technology while promoting industrial waste utilization at large scale.</div></div>","PeriodicalId":21153,"journal":{"name":"Resources Conservation and Recycling","volume":"220 ","pages":"Article 108328"},"PeriodicalIF":11.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sugar diet affects Culex pipiens early-life mortality, biochemical parameters, and immunocompetence","authors":"Olaya García-Ruiz,&nbsp;Juan Pascual-Gil,&nbsp;Cristina Megías,&nbsp;Josué Martínez-de la Puente,&nbsp;Jordi Figuerola,&nbsp;María José Ruiz-López","doi":"10.1002/ecs2.70158","DOIUrl":"https://doi.org/10.1002/ecs2.70158","url":null,"abstract":"<p>Mosquitoes obtain carbohydrates from plants, providing a fundamental source of energy for their metabolism. These nutrients influence mosquito immunocompetence and longevity, which has potential implications for the transmission of mosquito-borne pathogens. We experimentally evaluated how sugar concentration in the diet of <i>Culex pipiens</i> females affected their survival rate, body mass, body composition (i.e., protein, lipid, glucose, and glycogen), and immunocompetence (i.e., number of hemocytes). To do so, we reared field-captured larvae in the laboratory, and the emerged mosquito females were randomly assigned to different concentrations of sucrose offered ad libitum (mass/volume%: 0.5%, 1%, 2%, 4%, 8%, and 16%). These solutions were chosen to represent the range of concentrations used in lab experiments and to simulate low to medium sucrose availability similar to what mosquitoes might encounter in different plants. Mosquitoes were analyzed at three different ages, 7, 14, and 21 days postemergence (dpe). We observed that mosquitoes fed on the highest sucrose concentration (16%) had reduced survival at 21 dpe, but their dry body mass increased. Protein, lipid, glucose, and glycogen content increased significantly with mosquito dry body mass. Furthermore, the diets with higher sucrose concentrations increased the lipid and glucose content but decreased the quantity of glycogen. Mosquito age significantly affected lipid content, it increased in mosquitoes from 7 to 14 dpe, when it reached its maximum value, and decreased in 21 dpe mosquitoes. In addition, we found a significant effect of the interaction between age and sucrose concentration on the quantity of glycogen. Seven dpe mosquitoes fed with lower sucrose concentration diet (0.5%, 1%, and 2%) had more glycogen than older mosquitoes, but in mosquitoes fed with higher concentrations of sucrose, the significant effect of age disappeared. The total number of hemocytes and oenocytoids varied with sucrose concentration, being more abundant in mosquitoes fed with the 1% sucrose concentration. The changes caused by the sucrose concentration of the diet on their mortality rate until 21 dpe, body composition, and immunity may ultimately affect the vectorial capacity of mosquitoes. This study contributes to a better understanding of how nutrition may affect the immunity of vectors and the outcome of vector-pathogen interactions.</p>","PeriodicalId":48930,"journal":{"name":"Ecosphere","volume":"16 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecs2.70158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in permafrost bacterial community composition after thaw across multiple Alaskan locations","authors":"Alison K. Thurston,&nbsp;Stacey J. Doherty,&nbsp;Robert M. Jones,&nbsp;Thomas A. Douglas,&nbsp;Christopher C. M. Baker,&nbsp;Elizabeth J. Corriveau,&nbsp;Robyn A. Barbato","doi":"10.1002/ecs2.70260","DOIUrl":"https://doi.org/10.1002/ecs2.70260","url":null,"abstract":"<p>Increasing temperatures due to climate change are causing extensive permafrost thaw, impacting microbial communities and their processes. We conducted a laboratory thaw study comprising six Alaskan permafrost samples collected across a variety of locations to investigate how microbiome communities from different locations shift when experiencing the same thaw regime (stepwise increases in temperature over an 8-week incubation). The samples varied in bulk soil pH (4.45–6.59), water content (28%–265%), and carbon content (1%–29%). We surveyed the microbial community structure at each location pre- and post-thaw and determined whether communities were driven by stochastic or deterministic ecological assembly processes. We found that community composition and community assembly all varied by location. Dominant phyla were Firmicutes, followed by Actinobacteria and Proteobacteria. The deterministic process, homogeneous selection, was observed for five sites and was the most prevalent community assembly process at three of those sites, both pre- and post-thaw. At the two other sites, a combination of deterministic and stochastic processes influenced pre- and post-thaw community structure, with a large increase in drift post-thaw. Collectively, our findings suggest that permafrost attributes, such as edaphic conditions and pre-thaw community structure, exert an influence on the composition of microbial communities after thaw. However, the extent of this influence varies with location. The heterogeneous response of permafrost communities to thaw disturbance poses a significant challenge in accurately predicting the trajectory of microbial communities in response to climate change.</p>","PeriodicalId":48930,"journal":{"name":"Ecosphere","volume":"16 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecs2.70260","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multimethod approach for building climate literacy and a climate portal in the context of spatial regional planning in northern Patagonia","authors":"Claudio Pareja Pineda ,&nbsp;Álvaro Salazar ,&nbsp;María Paz Acuña ,&nbsp;Diego Ocampo Melgar ,&nbsp;María Ester Sepúlveda ,&nbsp;Francisco Bravo","doi":"10.1016/j.jenvman.2025.125397","DOIUrl":"10.1016/j.jenvman.2025.125397","url":null,"abstract":"<div><div>Integrating climate change considerations into planning at the subnational level is imperative for effective adaptation and risk reduction. Increased climate literacy among planners, supported by tools like climate portals can help this integration. This paper presents our approach to conveying a reasonable level of climate literacy and co-developing an online portal that provides useable climate information to planners. The approach was implemented in Northern Patagonia in collaboration with a Regional Government in preparation for their first-ever Land-Use Regional Plan. Our findings show that planners lack explicit experience in integrating climate considerations into planning but possess significant awareness of climate impacts. While national climate change assessments help identifying critical adaptation priorities, a coproduction approach was still needed for developing region-specific actionable climate information. By implementing the proposed multi-method approach, including interviews and simulated planning exercises, key features were identified and achieved: a learning process, through an interdisciplinary team, should be in place to promote usage, climate data must be at the relevant scale, contextual information should be included, the portal must be interactive so planners may incorporate their knowledge, and, since climate data can be understood in different ways, planning objectives can contextualize different interpretations. Hands-on workshops, integral to the co-production process, enhanced planners’ climate literacy by fostering practical understanding and use of climate indices. This collaborative approach highlights how tailored climate tools may bridge the gap between science and planning, providing critical support for effective climate adaptation.</div></div>","PeriodicalId":356,"journal":{"name":"Journal of Environmental Management","volume":"384 ","pages":"Article 125397"},"PeriodicalIF":8.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143878505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal and longitudinal dynamics of DOM within headwater streams of a tropical evergreen forest","authors":"Samantha N. Sullivan ,&nbsp;Jennifer C. Bowen ,&nbsp;Louis A. Kaplan ,&nbsp;Rose M. Cory ,&nbsp;Patrick G. Hatcher","doi":"10.1016/j.watres.2025.123668","DOIUrl":"10.1016/j.watres.2025.123668","url":null,"abstract":"<div><div>Dissolved organic matter (DOM) contributes to the energy flow in tropical rivers that dominate the global budget of riverine runoff to the ocean. Yet, the processes that control downstream DOM concentration and composition in the tropics are much less understood compared to higher latitudes. Here, we investigate seasonal and downstream changes in DOM concentration and composition in headwater streams draining the seasonally dry evergreen forest of the Río Tempisquito watershed in Costa Rica. We used dissolved organic carbon (DOC) analysis as a measure of DOM concentrations and UV–Vis, fluorescence spectroscopy and FT-ICR-MS to measure DOM composition. Seasonal differences in litterfall and day-to-day changes in rainfall controlled the DOC concentration. Elevated DOC concentrations were associated with inputs of terrestrial, humic-like DOM into the stream, and light rain falling on fresh leaf litter in the dry season led to nearly equivalent DOC concentrations as heavier rain falling on degraded litter in the wet season. The average nominal oxidation state of carbon (NOSC) in DOM molecular formulae differed between wet and dry seasons (seasonally) and with distance downstream (longitudinally). A higher NOSC of stream DOM in the dry versus wet season may be due to a peak in fresh litterfall in the dry season followed by the leaching of degraded litter during precipitation in the wet season. The shift in DOM toward a higher NOSC downstream in both seasons may be due to the selective metabolism of a more reduced, labile pool within DOM during downstream transport. We propose that the downstream changes in DOM composition in the dry tropical headwater streams of this study are driven by the preferential microbial metabolism of labile, reduced DOM compounds. These findings extend the River Continuum Concept by showing that DOM oxidation state can be a sensitive indicator of microbial metabolism in the absence of measurable decreases in downstream DOM concentrations.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123668"},"PeriodicalIF":11.4,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}