Cristina Charette, Mila Rautio, Gilbert Cabana, François Guillemette, Alison M. Derry
{"title":"Cascading Effects of Biological Invasion and Nutriment Enrichment Disrupt Freshwater Trophic Energy Pathways and Food Web Quality","authors":"Cristina Charette, Mila Rautio, Gilbert Cabana, François Guillemette, Alison M. Derry","doi":"10.1111/fwb.70126","DOIUrl":"https://doi.org/10.1111/fwb.70126","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70126","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145522092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Herbaceous marsh wetlands are widely distributed in northeast China, with huge soil organic carbon storage, playing an important role in the carbon cycle. The microbial communities in their soils are highly sensitive to environmental changes, and their respiration is a major component of wetland carbon cycling. However, there are few studies on the characteristics of soil bacteria in large-scale herbaceous marsh wetlands.
This study employed 16S rRNA sequencing technology to analyse soil bacterial communities in Carex marshes, Phragmites australis marshes and Carex-Deyeuxia angustifolia mixed marshes in Heilongjiang Province, and determined soil microbial respiration (SMR) through laboratory incubation methods. The characteristics and driving factors of soil bacterial communities and SMR were explored using one-way analysis of variance (ANOVA) and correlation analysis.
Our results showed that Proteobacteria and Acidobacteria were dominant in the soils of herbaceous marsh wetlands. The Carex marshes exhibited the highest soil bacterial diversity and soil microbial respiration (SMR), while Phragmites australis marshes showed the lowest. Investigations into driving factors revealed that soil moisture content (MC), pH, and bulk density (BD) significantly influenced bacterial communities, whereas MC and underground biomass (UB) significantly affected SMR. Structural equation modelling (SEM) demonstrated that vegetation types indirectly impact bacterial communities and diversity by regulating soil MC, thereby influencing SMR.
In conclusion, Carex spp.-dominated herbaceous marsh wetlands serve as hotspots for microbially mediated carbon fluxes and play a crucial role in the global carbon cycle. The findings provide empirical support for prioritising such wetlands in climate change mitigation strategies and offer insights into targeted wetland conservation and restoration.
{"title":"Variations in Soil Microbial Community Structure and Respiration Intensity in Different Typical Herbaceous Marsh Wetlands in Northeastern China","authors":"Yuchen Wang, Wenjing Xu, Guocan Zhang, Chen Yang, Li Zhang, Siyan Meng, Linlin Fan, Bing Yu","doi":"10.1111/fwb.70130","DOIUrl":"https://doi.org/10.1111/fwb.70130","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Herbaceous marsh wetlands are widely distributed in northeast China, with huge soil organic carbon storage, playing an important role in the carbon cycle. The microbial communities in their soils are highly sensitive to environmental changes, and their respiration is a major component of wetland carbon cycling. However, there are few studies on the characteristics of soil bacteria in large-scale herbaceous marsh wetlands.</li>\u0000 \u0000 \u0000 <li>This study employed 16S rRNA sequencing technology to analyse soil bacterial communities in Carex marshes, <i>Phragmites australis</i> marshes and Carex-Deyeuxia angustifolia mixed marshes in Heilongjiang Province, and determined soil microbial respiration (SMR) through laboratory incubation methods. The characteristics and driving factors of soil bacterial communities and SMR were explored using one-way analysis of variance (ANOVA) and correlation analysis.</li>\u0000 \u0000 \u0000 <li>Our results showed that Proteobacteria and Acidobacteria were dominant in the soils of herbaceous marsh wetlands. The <i>Carex</i> marshes exhibited the highest soil bacterial diversity and soil microbial respiration (SMR), while <i>Phragmites australis</i> marshes showed the lowest. Investigations into driving factors revealed that soil moisture content (MC), pH, and bulk density (BD) significantly influenced bacterial communities, whereas MC and underground biomass (UB) significantly affected SMR. Structural equation modelling (SEM) demonstrated that vegetation types indirectly impact bacterial communities and diversity by regulating soil MC, thereby influencing SMR.</li>\u0000 \u0000 \u0000 <li>In conclusion, <i>Carex</i> spp.-dominated herbaceous marsh wetlands serve as hotspots for microbially mediated carbon fluxes and play a crucial role in the global carbon cycle. The findings provide empirical support for prioritising such wetlands in climate change mitigation strategies and offer insights into targeted wetland conservation and restoration.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145521880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flooding is a critical driver of wetland plant growth. However, studies still often consider water depth or submergence duration in isolation. This limits our understanding of how hydrological variation affects plant performance. To address this, we have introduced cumulative emergence height (CEH) as a novel integrative parameter. This is defined as the product of emergence height above the water surface and the duration of emergence and quantifies the combined influence of hydrological exposure on wetland vegetation.
This study aims to evaluate the effectiveness of CEH in predicting biomass accumulation and physiological responses of wetland plants under flood conditions.
We investigated four dominant wetland species (Phragmites australis, Persicaria hydropiper, Phalaris arundinacea and Carex brevicuspis) in the Dongting Lake floodplain under four water levels (−30, 0, 30 and 60 cm) and three time points (45, 90 and 135 days). We measured aboveground and belowground biomass, leaf area, chlorophyll a and b concentration and nitrogen and phosphorus concentration. Partial least squares path modeling (PLS-PM) was used to explore direct and indirect relationships between CEH and plant traits.
Biomass and leaf area were significantly positively correlated with CEH, while chlorophyll and nitrogen concentrations showed negative correlations. CEH promoted biomass accumulation by increasing leaf area and individual number, and by reducing nitrogen and phosphorus concentrations. Species showed contrasting strategies: P. australis and P. hydropiper maintained consistent biomass growth, while P. arundinacea and C. brevicuspis peaked and declined under prolonged submergence.
CEH effectively integrates flood depth and duration into a single, ecologically meaningful parameter. It is a useful predictor of plant growth and physiological responses under dynamic flood conditions in the Dongting Lake wetland. As the study was limited to four species from a single wetland system, the findings apply primarily to similar ecological contexts.
{"title":"Cumulative Emergence Height Dominates Biomass Accumulation From Wetland Species Under Flood Conditions","authors":"Jiacheng Wang, Jiawei Shi, Lianlian Xi, Hui Fu, Guixiang Yuan, Aiping Wu, Yandong Niu, Yonghong Xie, Youzhi Li","doi":"10.1111/fwb.70127","DOIUrl":"https://doi.org/10.1111/fwb.70127","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Flooding is a critical driver of wetland plant growth. However, studies still often consider water depth or submergence duration in isolation. This limits our understanding of how hydrological variation affects plant performance. To address this, we have introduced cumulative emergence height (CEH) as a novel integrative parameter. This is defined as the product of emergence height above the water surface and the duration of emergence and quantifies the combined influence of hydrological exposure on wetland vegetation.</li>\u0000 \u0000 \u0000 <li>This study aims to evaluate the effectiveness of CEH in predicting biomass accumulation and physiological responses of wetland plants under flood conditions.</li>\u0000 \u0000 \u0000 <li>We investigated four dominant wetland species (<i>Phragmites australis</i>, <i>Persicaria hydropiper</i>, <i>Phalaris arundinacea</i> and <i>Carex brevicuspis</i>) in the Dongting Lake floodplain under four water levels (−30, 0, 30 and 60 cm) and three time points (45, 90 and 135 days). We measured aboveground and belowground biomass, leaf area, chlorophyll a and b concentration and nitrogen and phosphorus concentration. Partial least squares path modeling (PLS-PM) was used to explore direct and indirect relationships between CEH and plant traits.</li>\u0000 \u0000 \u0000 <li>Biomass and leaf area were significantly positively correlated with CEH, while chlorophyll and nitrogen concentrations showed negative correlations. CEH promoted biomass accumulation by increasing leaf area and individual number, and by reducing nitrogen and phosphorus concentrations. Species showed contrasting strategies: <i>P. australis</i> and <i>P. hydropiper</i> maintained consistent biomass growth, while <i>P. arundinacea</i> and <i>C. brevicuspis</i> peaked and declined under prolonged submergence.</li>\u0000 \u0000 \u0000 <li>CEH effectively integrates flood depth and duration into a single, ecologically meaningful parameter. It is a useful predictor of plant growth and physiological responses under dynamic flood conditions in the Dongting Lake wetland. As the study was limited to four species from a single wetland system, the findings apply primarily to similar ecological contexts.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anna Stanicka, Jarosław Kobak, Joanna Hildebrand, Anna Cichy, Kamil Wiśniewski, Daniel Szarmach, Kinga Lesiak, Joanna Urbaniak, Mateusz Augustyniak, Zuzanna Dlouhy, Szymon Graczyk, Arkadiusz Grzeczka, Zuzanna Kowaleska, Monika Lewalska, Katarzyna Lichocka, Sebastian Terebiński, Anna Wiśniewska, Elżbieta Żbikowska, Małgorzata Poznańska-Kakareko
Understanding the impact of invaders and parasites/pathogens and their interactions is desirable in an era of global environmental change. Such comprehensive insight is one of the drivers of sound conservation planning for biodiversity on local and global scales. Bivalves have experienced precipitous declines in species diversity and abundance in recent decades. Few threats have been reported for Sphaeriidae, mainly due to significant data deficiency, particularly at the species level.
We used a vulnerable worldwide fingernail clam Sphaerium rivicola as a model to find multi-species associations between the sphaeriid host, its digenean internal parasites, and fouling invasive dreissenid mussels (including potential interactions among the parasites and foulers). Individual clams were collected from the Włocławek Reservoir (Poland), representing a well-defined and representative population. We analysed host traits—shell length (size), wet weight per unit length (condition) and embryo presence (fertility)—in relation to two biotic stressors: digenean infection and fouling by invasive dreissenid mussels. Our aim was to assess their individual and combined effects on the clam host, and to test for potential interactions between parasites and foulers.
Biofouling and digenean infections had negative effects on clam growth and fertility. The combined presence of both stressors intensified the adverse impact compared to either alone. Tetracotyle metacercariae (recorded in bivalves for the first time) were positively associated with digeneans exploiting clams as first intermediate hosts, but negatively associated with echinostome metacercariae. No evidence was found for parasite dilution or facilitation by dreissenid mussels.
Presumably, the negative consequences for individual clam hosts may affect population-level success metrics. Disseminating the issues raised here will be one of the drivers for considering additional protective measures for endangered clam species.
{"title":"Many Evils Are Worse Than One: An Interplay Between Invasive Biofoulers and Parasites Helps Predict the Future of an Endangered Freshwater Fingernail Clam","authors":"Anna Stanicka, Jarosław Kobak, Joanna Hildebrand, Anna Cichy, Kamil Wiśniewski, Daniel Szarmach, Kinga Lesiak, Joanna Urbaniak, Mateusz Augustyniak, Zuzanna Dlouhy, Szymon Graczyk, Arkadiusz Grzeczka, Zuzanna Kowaleska, Monika Lewalska, Katarzyna Lichocka, Sebastian Terebiński, Anna Wiśniewska, Elżbieta Żbikowska, Małgorzata Poznańska-Kakareko","doi":"10.1111/fwb.70125","DOIUrl":"https://doi.org/10.1111/fwb.70125","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Understanding the impact of invaders and parasites/pathogens and their interactions is desirable in an era of global environmental change. Such comprehensive insight is one of the drivers of sound conservation planning for biodiversity on local and global scales. Bivalves have experienced precipitous declines in species diversity and abundance in recent decades. Few threats have been reported for Sphaeriidae, mainly due to significant data deficiency, particularly at the species level.</li>\u0000 \u0000 \u0000 <li>We used a vulnerable worldwide fingernail clam <i>Sphaerium rivicola</i> as a model to find multi-species associations between the sphaeriid host, its digenean internal parasites, and fouling invasive dreissenid mussels (including potential interactions among the parasites and foulers). Individual clams were collected from the Włocławek Reservoir (Poland), representing a well-defined and representative population. We analysed host traits—shell length (size), wet weight per unit length (condition) and embryo presence (fertility)—in relation to two biotic stressors: digenean infection and fouling by invasive dreissenid mussels. Our aim was to assess their individual and combined effects on the clam host, and to test for potential interactions between parasites and foulers.</li>\u0000 \u0000 \u0000 <li>Biofouling and digenean infections had negative effects on clam growth and fertility. The combined presence of both stressors intensified the adverse impact compared to either alone. Tetracotyle metacercariae (recorded in bivalves for the first time) were positively associated with digeneans exploiting clams as first intermediate hosts, but negatively associated with echinostome metacercariae. No evidence was found for parasite dilution or facilitation by dreissenid mussels.</li>\u0000 \u0000 \u0000 <li>Presumably, the negative consequences for individual clam hosts may affect population-level success metrics. Disseminating the issues raised here will be one of the drivers for considering additional protective measures for endangered clam species.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yue Wu, Siwen Chen, Qi Ye, Lei Jiang, Yiheng Chang, Wei Huang, Cheng Liu, Shuzhan Ma, Rong Jiang, Dandan Fei, Hongliang Xu, Xiaoli Shi, Kaining Chen
Submerged macrophytes influence sediment microbial communities in shallow lakes; however, the ecological roles of their community-level characteristics remain underexplored. In this study, we examined the relationships between macrophyte community coverage and diversity and the composition of sediment bacterial communities in Dongshan Bay, Lake Taihu.
We combined high-throughput sequencing, functional prediction, and multivariate statistical modelling to analyse sediment bacterial composition, potential metabolic functions, community assembly proceses, and their associations with macrophyte communities and environmental factors.
Macrophyte community structure explained more variation in sediment bacterial community structure than seasonal dynamics. Higher coverage and diversity were related to improved water clarity, elevated sediment nutrient concentrations, and enhanced bacterial metabolic potential. In macrophyte-dominated zones, bacterial communities were primarily structured by homogeneous selection, and microbial co-occurrence networks became less complex.
Our results indicate that species richness, diversity, and coverage most effectively capture the ecological functions of submerged macrophyte communities, and collectively influence sediment bacterial communities through multiple pathways, including habitat modification and altered selection pressures.
This study underscores the ecological role of macrophyte diversity and coverage in shaping sediment microbiota, offering insights for lake restoration strategies.
{"title":"Influence of Coverage and Diversity of Submerged Macrophytes on the Sediment Bacterial Community in Dongshan Bay, Lake Taihu","authors":"Yue Wu, Siwen Chen, Qi Ye, Lei Jiang, Yiheng Chang, Wei Huang, Cheng Liu, Shuzhan Ma, Rong Jiang, Dandan Fei, Hongliang Xu, Xiaoli Shi, Kaining Chen","doi":"10.1111/fwb.70120","DOIUrl":"https://doi.org/10.1111/fwb.70120","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Submerged macrophytes influence sediment microbial communities in shallow lakes; however, the ecological roles of their community-level characteristics remain underexplored. In this study, we examined the relationships between macrophyte community coverage and diversity and the composition of sediment bacterial communities in Dongshan Bay, Lake Taihu.</li>\u0000 \u0000 \u0000 <li>We combined high-throughput sequencing, functional prediction, and multivariate statistical modelling to analyse sediment bacterial composition, potential metabolic functions, community assembly proceses, and their associations with macrophyte communities and environmental factors.</li>\u0000 \u0000 \u0000 <li>Macrophyte community structure explained more variation in sediment bacterial community structure than seasonal dynamics. Higher coverage and diversity were related to improved water clarity, elevated sediment nutrient concentrations, and enhanced bacterial metabolic potential. In macrophyte-dominated zones, bacterial communities were primarily structured by homogeneous selection, and microbial co-occurrence networks became less complex.</li>\u0000 \u0000 \u0000 <li>Our results indicate that species richness, diversity, and coverage most effectively capture the ecological functions of submerged macrophyte communities, and collectively influence sediment bacterial communities through multiple pathways, including habitat modification and altered selection pressures.</li>\u0000 \u0000 \u0000 <li>This study underscores the ecological role of macrophyte diversity and coverage in shaping sediment microbiota, offering insights for lake restoration strategies.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Changes in Diversity With Stream Order in Particle-Associated and Free-Living Bacteria From Headwater Streams","authors":"Tadashi Ookami, Shunsuke Matsuoka, Tomohiro Yokobe, Ryunosuke Tateno","doi":"10.1111/fwb.70123","DOIUrl":"https://doi.org/10.1111/fwb.70123","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Timothy D. Jardine, Francisco Villamarín, Joseph E. Hawes, Joao Campos-Silva, Cristina M. Jacobi, Stephen Srayko, Alexander Pelletier, William E. Magnusson
{"title":"Seasonal Forest Resources Support Fish Biomass in Floodplain Lakes of an Amazonian Tributary","authors":"Timothy D. Jardine, Francisco Villamarín, Joseph E. Hawes, Joao Campos-Silva, Cristina M. Jacobi, Stephen Srayko, Alexander Pelletier, William E. Magnusson","doi":"10.1111/fwb.70121","DOIUrl":"https://doi.org/10.1111/fwb.70121","url":null,"abstract":"<p>\u0000 \u0000 </p>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.70121","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145407266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information - Cover and Ed Board","authors":"","doi":"10.1111/fwb.14284","DOIUrl":"https://doi.org/10.1111/fwb.14284","url":null,"abstract":"","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/fwb.14284","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145385013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mian Adnan Kakakhel, Nishita Narwal, Sanaullah Khan, Alam Khan, Majid Rasta, Shi Xiaotao, Yujiao Wu
Hydraulic engineering alters freshwater fish swimming performance by affecting fish physiology; however, the mechanistic links between water flow-induced bacterial shift and locomotor impairment remain poorly understood.
This study investigated the effects of varying flow velocities on intestinal microbiota composition, immune gene expression, and swimming performance in grass carp (Ctenopharyngodon idella), a commercially important freshwater species. Fish were exposed to three flow regimes: low, medium, and high water velocity in a controlled open recirculation system over a defined exposure period.
Swimming performance was significantly impaired under increasing flow velocity (R2 = 0.9128; p < 0.001), indicating reduced locomotive efficiency.
High-flow exposure also induced notable gut microbial dysbiosis (p = 0.0010; Adonis R2 = 0.2529), with elevated relative abundance of opportunistic and potentially pathogenic bacteria, including Aeromonas, Acinetobacter, and Vibrio spp. (p < 0.05***). This microbial imbalance was paralleled by the significant upregulation of key immune response genes (p < 0.001), reflecting a systemic stress-induced immunomodulatory effect.
These findings identify water flow velocity as a critical but underrecognized abiotic factor that not only impairs physical performance, also disrupts microbial homeostasis and triggers host immune responses. This study provides novel insights into the complex interactions among chronic hydrodynamic stress, host-associated microbiota, and immune regulation in freshwater fish. The obtained findings have far-reaching implications for aquaculture system design, environmental risk assessment, and the conservation of freshwater biodiversity under changing flow regimes.
{"title":"Hydraulic Engineering Affects Freshwater Fish Swimming Performance by Shifting Intestinal Bacterial Composition. A Microbiological Mechanism","authors":"Mian Adnan Kakakhel, Nishita Narwal, Sanaullah Khan, Alam Khan, Majid Rasta, Shi Xiaotao, Yujiao Wu","doi":"10.1111/fwb.70122","DOIUrl":"https://doi.org/10.1111/fwb.70122","url":null,"abstract":"<div>\u0000 \u0000 <p>\u0000 \u0000 </p><ol>\u0000 \u0000 \u0000 <li>Hydraulic engineering alters freshwater fish swimming performance by affecting fish physiology; however, the mechanistic links between water flow-induced bacterial shift and locomotor impairment remain poorly understood.</li>\u0000 \u0000 \u0000 <li>This study investigated the effects of varying flow velocities on intestinal microbiota composition, immune gene expression, and swimming performance in grass carp (<i>Ctenopharyngodon idella</i>), a commercially important freshwater species. Fish were exposed to three flow regimes: low, medium, and high water velocity in a controlled open recirculation system over a defined exposure period.</li>\u0000 \u0000 \u0000 <li>Swimming performance was significantly impaired under increasing flow velocity (<i>R</i><sup>2</sup> = 0.9128; <i>p</i> < 0.001), indicating reduced locomotive efficiency.</li>\u0000 \u0000 \u0000 <li>High-flow exposure also induced notable gut microbial dysbiosis (<i>p</i> = 0.0010; Adonis <i>R</i><sup>2</sup> = 0.2529), with elevated relative abundance of opportunistic and potentially pathogenic bacteria, including <i>Aeromonas</i>, <i>Acinetobacter</i>, and <i>Vibrio</i> spp. (<i>p</i> < 0.05***). This microbial imbalance was paralleled by the significant upregulation of key immune response genes (<i>p</i> < 0.001), reflecting a systemic stress-induced immunomodulatory effect.</li>\u0000 \u0000 \u0000 <li>These findings identify water flow velocity as a critical but underrecognized abiotic factor that not only impairs physical performance, also disrupts microbial homeostasis and triggers host immune responses. This study provides novel insights into the complex interactions among chronic hydrodynamic stress, host-associated microbiota, and immune regulation in freshwater fish. The obtained findings have far-reaching implications for aquaculture system design, environmental risk assessment, and the conservation of freshwater biodiversity under changing flow regimes.</li>\u0000 </ol>\u0000 \u0000 </div>","PeriodicalId":12365,"journal":{"name":"Freshwater Biology","volume":"70 11","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145385012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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