Eutrophication is generally considered as a major factor in the outbreak of cyanobacterial blooms, yet some species can thrive even bloom under low phosphorus (P) conditions. However, the underlying physiological and molecular mechanisms enabling cyanobacterial proliferation in P-limited environments remain poorly understood. This study identifies cyanophycin (CP) accumulation as a novel low-P response mechanism and compares the strategies of nitrogen-fixing Dolichospermum and non-nitrogen-fixing Microcystis. Dolichospermum adapts to low P stress via a "CP-gene synergy" pattern, with significant upregulation of the CP synthesis gene (cphA) and peak CP levels reaching 3.5% of dry weight. This nitrogen-storage polymer balances the carbon-to-nitrogen ratio within cells. In contrast, Microcystis showed limited CP production (peak: 0.6% DW) with 57% downregulation of cphA under low P. Beyond the CP accumulation strategy, the two cyanobacterial species additionally exhibited distinct P utilization strategies: Microcystis predominantly employed polyphosphate storage, while Dolichospermum obtained P through alkaline phosphatase secretion. These differential strategies resulted in species-specific photoregulatory responses under P-limited conditions. Dolichospermum enhances PSII efficiency to compensate for reduced light capture, while Microcystis increases light capture to relieve energy stress. These differentiated strategies provide both genera with a sustained competitive advantage in aquatic environments, allowing them to occupy ecological niches even in low-P conditions.
{"title":"From Cyanophycin Accumulation to Photoregulation: Divergent Phosphorus Stress Response Mechanisms in Dolichospermum and Microcystis","authors":"Zhenghan Liu, Meng Tan, Jingjie Zhang, Dong Bai, Lingling Wan, Xiaowen Li, Chunlei Song, Xiuyun Cao","doi":"10.1016/j.watres.2026.125513","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125513","url":null,"abstract":"Eutrophication is generally considered as a major factor in the outbreak of cyanobacterial blooms, yet some species can thrive even bloom under low phosphorus (P) conditions. However, the underlying physiological and molecular mechanisms enabling cyanobacterial proliferation in P-limited environments remain poorly understood. This study identifies cyanophycin (CP) accumulation as a novel low-P response mechanism and compares the strategies of nitrogen-fixing <em>Dolichospermum</em> and non-nitrogen-fixing <em>Microcystis. Dolichospermum</em> adapts to low P stress via a \"CP-gene synergy\" pattern, with significant upregulation of the CP synthesis gene <em>(cph</em>A) and peak CP levels reaching 3.5% of dry weight. This nitrogen-storage polymer balances the carbon-to-nitrogen ratio within cells. In contrast, <em>Microcystis</em> showed limited CP production (peak: 0.6% DW) with 57% downregulation of <em>cph</em>A under low P. Beyond the CP accumulation strategy, the two cyanobacterial species additionally exhibited distinct P utilization strategies: <em>Microcystis</em> predominantly employed polyphosphate storage, while <em>Dolichospermum</em> obtained P through alkaline phosphatase secretion. These differential strategies resulted in species-specific photoregulatory responses under P-limited conditions. <em>Dolichospermum</em> enhances PSII efficiency to compensate for reduced light capture, while <em>Microcystis</em> increases light capture to relieve energy stress. These differentiated strategies provide both genera with a sustained competitive advantage in aquatic environments, allowing them to occupy ecological niches even in low-P conditions.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"104 1236 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129692","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}
Pub Date : 2026-02-04DOI: 10.1016/j.watres.2026.125512
Mingyue Li, Shilong Li, Qiusheng Gao, Liang Duan
Accurate accounting of greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs) is critical to achieving carbon reduction targets, optimizing operation and management, and promoting sustainable development of the industry. Currently, the accurate accounting of GHG emissions from WWTPs primarily considers the differences in processes and regions, but overlooks the impact of temporal variations on GHG emissions. In this study, a long-term study was conducted in the Beijing-Tianjin-Hebei region on WWTPs using the AAO process. The characteristics of GHG emissions from WWTPs were analyzed, and GHG emissions from WWTPs in different seasons were compared in multiple dimensions, emphasizing the seasonal differences in GHG emission factor (EF) from WWTPs. The results showed that the direct emission of GHG increased significantly in summer, and the mean EF-CH4 was maximized to 13.35±4.91 gCH4/kgCOD, which was 1.1-2.5 times higher than the EF in other seasons. The mean EF-N2O was maximized at 4.17 gN2O/kgTN, which was 1.3-8.2 times higher than the EF in other seasons. Therefore, the influence of seasonal differences on GHG emissions from WWTPs should not be ignored, and it is of great significance to improve the accuracy of GHG emissions accounting in this industry.
{"title":"Improving the accuracy of greenhouse gas accounting for wastewater treatment plants: seasonal differences must not be overlooked","authors":"Mingyue Li, Shilong Li, Qiusheng Gao, Liang Duan","doi":"10.1016/j.watres.2026.125512","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125512","url":null,"abstract":"Accurate accounting of greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs) is critical to achieving carbon reduction targets, optimizing operation and management, and promoting sustainable development of the industry. Currently, the accurate accounting of GHG emissions from WWTPs primarily considers the differences in processes and regions, but overlooks the impact of temporal variations on GHG emissions. In this study, a long-term study was conducted in the Beijing-Tianjin-Hebei region on WWTPs using the AAO process. The characteristics of GHG emissions from WWTPs were analyzed, and GHG emissions from WWTPs in different seasons were compared in multiple dimensions, emphasizing the seasonal differences in GHG emission factor (EF) from WWTPs. The results showed that the direct emission of GHG increased significantly in summer, and the mean EF-CH<sub>4</sub> was maximized to 13.35±4.91 gCH<sub>4</sub>/kgCOD, which was 1.1-2.5 times higher than the EF in other seasons. The mean EF-N<sub>2</sub>O was maximized at 4.17 gN<sub>2</sub>O/kgTN, which was 1.3-8.2 times higher than the EF in other seasons. Therefore, the influence of seasonal differences on GHG emissions from WWTPs should not be ignored, and it is of great significance to improve the accuracy of GHG emissions accounting in this industry.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"106 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110888","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}
Pub Date : 2026-02-04DOI: 10.1016/j.watres.2026.125500
Amir Hossein Behroozi, Muayad Al-Shaeli, Vahid Vatanpour
{"title":"Conductive Nanofiltration: From Materials to Applications","authors":"Amir Hossein Behroozi, Muayad Al-Shaeli, Vahid Vatanpour","doi":"10.1016/j.watres.2026.125500","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125500","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"74 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110892","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}
Pub Date : 2026-02-04DOI: 10.1016/j.watres.2026.125504
Jingyu Qiu, Lei Cheng, Lihao Zhou, Yuhan Yang, Kunming Wu, Jun Zhang, Wenwen Tian, Pan Liu
{"title":"An explainable and transferable deep learning framework for spatiotemporal urban flood prediction by integrating Vision Transformer and U-Net","authors":"Jingyu Qiu, Lei Cheng, Lihao Zhou, Yuhan Yang, Kunming Wu, Jun Zhang, Wenwen Tian, Pan Liu","doi":"10.1016/j.watres.2026.125504","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125504","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"1 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110894","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}
Pub Date : 2026-02-04DOI: 10.1016/j.watres.2026.125508
Keran Zhang, Kristin Scharnweber, Juliane Annemieke Riedel, Anna-Lena Zocher, Michael Bau
{"title":"Behavior of geogenic and anthropogenic rare earth elements and yttrium in a natural freshwater ecosystem","authors":"Keran Zhang, Kristin Scharnweber, Juliane Annemieke Riedel, Anna-Lena Zocher, Michael Bau","doi":"10.1016/j.watres.2026.125508","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125508","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"9 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134988","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}
Pub Date : 2026-02-04DOI: 10.1016/j.watres.2026.125507
Ivan V. Krickov, Sergey V. Loiko, Artem G. Lim, Darya M. Kuzmina, Georgy I. Istigechev, Liudmila S. Shirokova, Yuri S. Pupyshev, Oleg S. Pokrovsky
Organic and inorganic solute fluxes from soils to rivers follow a hydrological continuum linking terrestrial and aquatic compartments, yet this cascade remains poorly constrained in permafrost regions despite its importance for carbon and greenhouse gas (GHG) cycling. We investigated six hydrological continuums—soil water, fen, lake, riparian zone, stream, and river—across a 1500 km north–south transect of the Western Siberian Lowland, spanning the full gradient from permafrost-free taiga to continuous permafrost tundra. During summer baseflow, surface and soil waters were analyzed for dissolved organic carbon (DOC), CO2, CH4, and 40 major and trace elements. DOC, CO2, and CH4 concentrations systematically decreased from soils and fens toward lakes and rivers, highlighting headwaters as dominant sources of carbon and GHGs. Aluminum covaried with DOC, consistent with organic complexation and downstream pH increases, whereas Fe and Mn reflected local redox variability. In contrast, Ca, Mg, Sr, and soluble anions increased downstream in southern, permafrost-free systems, indicating active groundwater inputs, while no such trend was observed in tundra sites under continuous permafrost, pointing to strong hydrological isolation. DOC declined with increasing drainage area, whereas CO2 and CH4 showed no consistent dependence on watershed size. Nutrients (Si, P) increased downstream mainly within discontinuous permafrost zones, suggesting enhanced subsurface contributions. Principal component analysis revealed two dominant patterns of covariation: one linking DOC, Fe, Al, and low-mobility lithogenic trace elements, consistent with colloidal transport of organic and organo-ferric complexes, and a second associated with electrical conductivity and labile ions, reflecting variable groundwater influence and subsurface–surface connectivity. GHG concentrations were largely independent of these patterns and instead related to local redox conditions and subsoil CO₂–CH₄ inputs. Overall, this study provides the first integrated, pan-regional assessment of coupled organic carbon, greenhouse gases, and major–trace element dynamics along complete hydrological continuums spanning the full permafrost gradient of the Western Siberian Lowland. By combining multi-compartment sampling with a space-for-time framework, we identify two fundamental controls—colloidal transport limitation and groundwater-driven source limitation—that unify solute behavior across climate zones. The results demonstrate how permafrost extent governs hydrological connectivity, biogeochemical processing, and GHG regimes, offering a mechanistic basis for predicting Arctic river responses to thaw, warming, and changing water–groundwater exchange.
{"title":"Hydrological Continuums Across Climate and Permafrost Gradients: Spatial Patterns of Organic Carbon, Greenhouse Gases, and Major and Trace Elements","authors":"Ivan V. Krickov, Sergey V. Loiko, Artem G. Lim, Darya M. Kuzmina, Georgy I. Istigechev, Liudmila S. Shirokova, Yuri S. Pupyshev, Oleg S. Pokrovsky","doi":"10.1016/j.watres.2026.125507","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125507","url":null,"abstract":"Organic and inorganic solute fluxes from soils to rivers follow a hydrological continuum linking terrestrial and aquatic compartments, yet this cascade remains poorly constrained in permafrost regions despite its importance for carbon and greenhouse gas (GHG) cycling. We investigated six hydrological continuums—soil water, fen, lake, riparian zone, stream, and river—across a 1500 km north–south transect of the Western Siberian Lowland, spanning the full gradient from permafrost-free taiga to continuous permafrost tundra. During summer baseflow, surface and soil waters were analyzed for dissolved organic carbon (DOC), CO<sub>2</sub>, CH<sub>4</sub>, and 40 major and trace elements. DOC, CO<sub>2</sub>, and CH<sub>4</sub> concentrations systematically decreased from soils and fens toward lakes and rivers, highlighting headwaters as dominant sources of carbon and GHGs. Aluminum covaried with DOC, consistent with organic complexation and downstream pH increases, whereas Fe and Mn reflected local redox variability. In contrast, Ca, Mg, Sr, and soluble anions increased downstream in southern, permafrost-free systems, indicating active groundwater inputs, while no such trend was observed in tundra sites under continuous permafrost, pointing to strong hydrological isolation. DOC declined with increasing drainage area, whereas CO<sub>2</sub> and CH<sub>4</sub> showed no consistent dependence on watershed size. Nutrients (Si, P) increased downstream mainly within discontinuous permafrost zones, suggesting enhanced subsurface contributions. Principal component analysis revealed two dominant patterns of covariation: one linking DOC, Fe, Al, and low-mobility lithogenic trace elements, consistent with colloidal transport of organic and organo-ferric complexes, and a second associated with electrical conductivity and labile ions, reflecting variable groundwater influence and subsurface–surface connectivity. GHG concentrations were largely independent of these patterns and instead related to local redox conditions and subsoil CO₂–CH₄ inputs. Overall, this study provides the first integrated, pan-regional assessment of coupled organic carbon, greenhouse gases, and major–trace element dynamics along complete hydrological continuums spanning the full permafrost gradient of the Western Siberian Lowland. By combining multi-compartment sampling with a space-for-time framework, we identify two fundamental controls—colloidal transport limitation and groundwater-driven source limitation—that unify solute behavior across climate zones. The results demonstrate how permafrost extent governs hydrological connectivity, biogeochemical processing, and GHG regimes, offering a mechanistic basis for predicting Arctic river responses to thaw, warming, and changing water–groundwater exchange.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"2 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146129693","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}
Pub Date : 2026-02-03DOI: 10.1016/j.watres.2026.125505
Morgan Peel, Kai Solanki, Philip Brunner, Daniel Hunkeler, Oliver S. Schilling, Rolf Kipfer
{"title":"A CONTROLLED AND SCALABLE NOBLE GAS INJECTION METHOD FOR QUANTITATIVE TRACER TESTS IN HYDROGEOLOGICAL STUDIES","authors":"Morgan Peel, Kai Solanki, Philip Brunner, Daniel Hunkeler, Oliver S. Schilling, Rolf Kipfer","doi":"10.1016/j.watres.2026.125505","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125505","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"41 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110959","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":"Evaluation of contaminant mitigation strategies in a karst aquifer through high-fidelity numerical modeling of flow and transport processes","authors":"Xiaofeng Xiong, Xiaokang Zheng, Zhibing Yang, Liuzheng Dai, Zhimin Xu, Yong Chang","doi":"10.1016/j.watres.2026.125506","DOIUrl":"https://doi.org/10.1016/j.watres.2026.125506","url":null,"abstract":"","PeriodicalId":443,"journal":{"name":"Water Research","volume":"68 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110960","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}
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