Pub Date : 2025-04-18DOI: 10.1016/j.limno.2025.126249
Julieta Cuevas, Guillermo Chalar, Sol De Giacomi, Mauricio González-Piana, Carmela Carballo
Reservoirs significantly influence aquatic ecosystems by modifying river flows and forming artificial lakes. This study examines the zooplankton communities in two Uruguayan connected reservoirs, Bonete and Baygorria, focusing on the impact of different water residence times. Upstream Bonete has a long retention time of 140 days, whereas Baygorria has a short retention time of 3 days. The investigation was conducted over 2019–2020, involving ten sampling events at three depths. Physical and chemical variables, including temperature, dissolved oxygen, pH, turbidity, chl-a, total nitrogen, total phosphorus, and organic matter concentrations were measured. Zooplankton biomass and community structure were analyzed through Redundancy Analysis (RDA). Results indicated higher zooplankton biomass in Bonete, with significant seasonal and vertical variations linked to environmental factors. Temperature, chl-a concentration, and water residence time were identified as key determinants. The study highlights the role of water residence time in shaping zooplankton communities. The findings underscore the need for tailored management strategies to address the ecological dynamics of reservoirs.
{"title":"Seasonal variation of zooplankton community structure between two subtropical reservoirs of contrasting hydraulic retention time","authors":"Julieta Cuevas, Guillermo Chalar, Sol De Giacomi, Mauricio González-Piana, Carmela Carballo","doi":"10.1016/j.limno.2025.126249","DOIUrl":"10.1016/j.limno.2025.126249","url":null,"abstract":"<div><div>Reservoirs significantly influence aquatic ecosystems by modifying river flows and forming artificial lakes. This study examines the zooplankton communities in two Uruguayan connected reservoirs, Bonete and Baygorria, focusing on the impact of different water residence times. Upstream Bonete has a long retention time of 140 days, whereas Baygorria has a short retention time of 3 days. The investigation was conducted over 2019–2020, involving ten sampling events at three depths. Physical and chemical variables, including temperature, dissolved oxygen, pH, turbidity, chl-a, total nitrogen, total phosphorus, and organic matter concentrations were measured. Zooplankton biomass and community structure were analyzed through Redundancy Analysis (RDA). Results indicated higher zooplankton biomass in Bonete, with significant seasonal and vertical variations linked to environmental factors. Temperature, chl-a concentration, and water residence time were identified as key determinants. The study highlights the role of water residence time in shaping zooplankton communities. The findings underscore the need for tailored management strategies to address the ecological dynamics of reservoirs.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126249"},"PeriodicalIF":2.0,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-04-17DOI: 10.1016/j.limno.2025.126251
Matheus Henrique de Oliveira de Matos , Loiani Oliveira Santana , Felipe Rafael de Oliveira , Melissa Progênio , Edilaine Corrêa Leite , João Vitor Bredariol , Luiz Felipe Machado Velho
The aim of this study was to investigate the temporal dynamics of planktonic ciliate communities, based on daily fluctuations between different hydrological periods in a eutrophic urban lake located in the city of Maringá, Paraná, Brazil. We hypothesized that abundance would vary more between collection days than between hydrological periods, whereas richness and selection would vary more between hydrological periods than collection days. Ciliated protists were sampled during two distinct hydrological periods: a dry period in September 2018 and a rainy period in January 2019. Sampling was conducted 10 times during each period, with collections every 3 days over 30 days. Throughout the study, 84 morphospecies were recorded. The Prostomatida group dominated in both periods, contributing to 37.1 % of the total abundance in the dry season and 74 % in the rainy season. Other representative groups included Peritrichia (35.7 % in the dry season) and less abundant taxa such as Nassulida, Colpodea, and Cyrtophorida (8.5 % in the rainy season). Abundance varied significantly in the short term (i.e. between sampling days) and between hydrological periods (dry and rainy), with higher values during the rainy season (mean ± SE: 1250 ± 150 Ind.L⁻¹) compared to the dry season (mean ± SE: 850 ± 120 Ind.L⁻¹). Differences in richness were not significant between the hydrological periods. However, there was significant daily variation during the rainy season. Species composition differed only between hydrological periods, as predicted. This study shows that the hydrological regime significantly influences ciliate communities, with variations in richness, abundance, and composition occurring over short periods. Therefore, it is recommended that these organisms be analyzed continuously, across short intervals, and seasonally. This approach is necessary because their responses to environmental monitoring may vary depending on the sampling period, given their high sensitivity to environmental changes.
{"title":"Short-term and seasonal dynamics of planktonic protist community (Alveolata, Ciliophora) in a neotropical urban lake, Maringá - Paraná, Brazil","authors":"Matheus Henrique de Oliveira de Matos , Loiani Oliveira Santana , Felipe Rafael de Oliveira , Melissa Progênio , Edilaine Corrêa Leite , João Vitor Bredariol , Luiz Felipe Machado Velho","doi":"10.1016/j.limno.2025.126251","DOIUrl":"10.1016/j.limno.2025.126251","url":null,"abstract":"<div><div>The aim of this study was to investigate the temporal dynamics of planktonic ciliate communities, based on daily fluctuations between different hydrological periods in a eutrophic urban lake located in the city of Maringá, Paraná, Brazil. We hypothesized that abundance would vary more between collection days than between hydrological periods, whereas richness and selection would vary more between hydrological periods than collection days. Ciliated protists were sampled during two distinct hydrological periods: a dry period in September 2018 and a rainy period in January 2019. Sampling was conducted 10 times during each period, with collections every 3 days over 30 days. Throughout the study, 84 morphospecies were recorded. The Prostomatida group dominated in both periods, contributing to 37.1 % of the total abundance in the dry season and 74 % in the rainy season. Other representative groups included Peritrichia (35.7 % in the dry season) and less abundant taxa such as Nassulida, Colpodea, and Cyrtophorida (8.5 % in the rainy season). Abundance varied significantly in the short term (i.e. between sampling days) and between hydrological periods (dry and rainy), with higher values during the rainy season (mean ± SE: 1250 ± 150 Ind.L⁻¹) compared to the dry season (mean ± SE: 850 ± 120 Ind.L⁻¹). Differences in richness were not significant between the hydrological periods. However, there was significant daily variation during the rainy season. Species composition differed only between hydrological periods, as predicted. This study shows that the hydrological regime significantly influences ciliate communities, with variations in richness, abundance, and composition occurring over short periods. Therefore, it is recommended that these organisms be analyzed continuously, across short intervals, and seasonally. This approach is necessary because their responses to environmental monitoring may vary depending on the sampling period, given their high sensitivity to environmental changes.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126251"},"PeriodicalIF":2.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143848646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-04-11DOI: 10.1016/j.limno.2025.126250
Daniel Pelz , Thomas Friedrich , Bernhard Zeiringer , Thomas Hein , Günther Unfer
This study investigates the reproductive ecology of three rheophilic fish species (Chondrostoma nasus, Barbus barbus and Vimba vimba) in the River Traisen, Austria. The main objectives were to describe the spawning sites of these species and to describe the development of nase eggs and larvae in situ. The study also examines the immigration patterns from the Danube into the Traisen in relation to discharge and water temperature. The fieldwork was carried out between March and June 2020 in the lower reaches of the Traisen (11 km renaturalized river section and 4 km residual water section). In addition to visual counts, a drone (UAV) and underwater cameras were used to quantify and document spawning behavior. At the spawning sites the parameters water depth, flow velocity, temperature and substrate type were recorded. The spawning site characteristics of nase and barbel were consistent with previous studies. The vimba bream spawned at a water temperature of 13–17 °C, a water depth of 39 ± 9 cm and a flow velocity of 93 ± 19 cm/s and was described for the first time for a Central European river population. The development of the nase from eggs to fry was documented in the field; the incubation of the eggs lasted 30 days with a mean water temperature of 11.4 °C. Only a few barbel and vimba bream used the restored section for spawning, the majority of both and all nase spawned in the residual flow stretch upstream, where they were prevented from migrating further due to the low discharge.
{"title":"Reproductive ecology of three rheophilic fish species in the Austrian Danube River system: Insights into the spawning of Chondrostoma nasus, Barbus barbus, and Vimba vimba, and the larval development of C. nasus in the River Traisen","authors":"Daniel Pelz , Thomas Friedrich , Bernhard Zeiringer , Thomas Hein , Günther Unfer","doi":"10.1016/j.limno.2025.126250","DOIUrl":"10.1016/j.limno.2025.126250","url":null,"abstract":"<div><div>This study investigates the reproductive ecology of three rheophilic fish species (<em>Chondrostoma nasus, Barbus barbus</em> and <em>Vimba vimba</em>) in the River Traisen, Austria. The main objectives were to describe the spawning sites of these species and to describe the development of nase eggs and larvae in situ. The study also examines the immigration patterns from the Danube into the Traisen in relation to discharge and water temperature. The fieldwork was carried out between March and June 2020 in the lower reaches of the Traisen (11 km renaturalized river section and 4 km residual water section). In addition to visual counts, a drone (UAV) and underwater cameras were used to quantify and document spawning behavior. At the spawning sites the parameters water depth, flow velocity, temperature and substrate type were recorded. The spawning site characteristics of nase and barbel were consistent with previous studies. The vimba bream spawned at a water temperature of 13–17 °C, a water depth of 39 ± 9 cm and a flow velocity of 93 ± 19 cm/s and was described for the first time for a Central European river population. The development of the nase from eggs to fry was documented in the field; the incubation of the eggs lasted 30 days with a mean water temperature of 11.4 °C. Only a few barbel and vimba bream used the restored section for spawning, the majority of both and all nase spawned in the residual flow stretch upstream, where they were prevented from migrating further due to the low discharge.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126250"},"PeriodicalIF":2.0,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-04-09DOI: 10.1016/j.limno.2025.126252
Abdulhamid Yusuf , Duan Lei , Yaqiao Sun , Shuo Duan , Yunzeng Zhang
The hyporheic zone (HZ) plays a critical role in nitrogen transformation, yet the impact of hydrodynamic variability on microbial community dynamics within HZ sediments remains poorly understood. This study investigates how different hydrodynamic conditions affect microbial communities in HZ sediments using a simulation device to analyze groundwater-surface water interactions. Results indicate a significant reduction in nitrate (NO₃⁻) concentrations, with decreases of 93.81 % under upwelling (from 4.68 mg/L to 0.30 mg/L) and 91.05 % under downwelling conditions (from 6.2 mg/L to 0.55 mg/L). Concurrently, peaks in nitrite (NO₂⁻) concentrations were observed during denitrification processes (P < 0.05). High-throughput sequencing revealed diverse bacterial communities, predominantly consisting of Proteobacteria (40–46 % relative abundance) and Actinobacteria, with downwelling sediments exhibiting greater microbial richness (ACE index) compared to upwelling sediments (P < 0.05). The Shannon diversity indices showed mean values of 6.17 for downwelling and 5.81 for upwelling sediments. These findings demonstrate that hydrodynamic conditions significantly influence both microbial community structure and nitrogen transformation processes, underscoring the microbial role in biogeochemical processes of nitrogen cycling. Future research should examine the long-term effects of hydrological fluctuations on microbial dynamics in the HZ to enhance our understanding of ecosystem sustainability.
{"title":"Nitrogen transformation and microbial community interactions in hydrodynamic heterogeneous hyporheic zone sediment: Insights for ecosystem sustainability","authors":"Abdulhamid Yusuf , Duan Lei , Yaqiao Sun , Shuo Duan , Yunzeng Zhang","doi":"10.1016/j.limno.2025.126252","DOIUrl":"10.1016/j.limno.2025.126252","url":null,"abstract":"<div><div>The hyporheic zone (HZ) plays a critical role in nitrogen transformation, yet the impact of hydrodynamic variability on microbial community dynamics within HZ sediments remains poorly understood. This study investigates how different hydrodynamic conditions affect microbial communities in HZ sediments using a simulation device to analyze groundwater-surface water interactions. Results indicate a significant reduction in nitrate (NO₃⁻) concentrations, with decreases of 93.81 % under upwelling (from 4.68 mg/L to 0.30 mg/L) and 91.05 % under downwelling conditions (from 6.2 mg/L to 0.55 mg/L). Concurrently, peaks in nitrite (NO₂⁻) concentrations were observed during denitrification processes (P < 0.05). High-throughput sequencing revealed diverse bacterial communities, predominantly consisting of <em>Proteobacteria</em> (40–46 % relative abundance) and <em>Actinobacteria,</em> with downwelling sediments exhibiting greater microbial richness (ACE index) compared to upwelling sediments (P < 0.05). The Shannon diversity indices showed mean values of 6.17 for downwelling and 5.81 for upwelling sediments. These findings demonstrate that hydrodynamic conditions significantly influence both microbial community structure and nitrogen transformation processes, underscoring the microbial role in biogeochemical processes of nitrogen cycling. Future research should examine the long-term effects of hydrological fluctuations on microbial dynamics in the HZ to enhance our understanding of ecosystem sustainability.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126252"},"PeriodicalIF":2.0,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-04-04DOI: 10.1016/j.limno.2025.126248
Jiangqianhui Qi , Yang Wang , Jing Yuan , Chuansong Liao , Jiashou Liu , Chuanbo Guo
The Yangtze River and its adjacent lakes form a complex river-lake ecosystem, rich in aquatic biodiversity, with zooplankton serving as a key component. Zooplankton is important in nutrient circulation and energy flow, and also serves as an important indicator reflecting water quality and the overall health of aquatic ecosystems. Studying the changes in zooplankton community structure, which fluctuate with physicochemical environment, is crucial for understanding variations in lake water quality. We surveyed 15 shallow lakes of this river-lake ecosystem in the middle reaches of the Yangtze River. Using K-means cluster analysis based on the relative density ratios of Protozoa, Rotifera, Cladocera, and Copepoda, we classified the lakes into three distinct groups (Groups I to III). Our results showed a decline in the density and biomass proportions of Cladocera and Copepoda, contrasted by increases in those of Protozoa and Rotifera from Group I to III, alongside a rise in the Trophic Level Index, indicating progressive eutrophication. A composite diversity index, derived from the diversity indices of Shannon-Weiner, Pielou, and Margalef by using Principal Component Analysis, revealed an increase in diversity from Group I to III, suggesting a gradual stabilization of the community structure. Redundancy Analysis identified water temperature (WT), chlorophyll-a (Chl-a), secchi depth (SD), orthophosphates (PO43-), and dissolved oxygen (DO) as the primary environmental factors influencing zooplankton community structure. This study provides critical insights into the dynamics and environmental drivers of zooplankton community in these 15 lakes, offering a foundation for managing water eutrophication and facilitating the restoration of these aquatic ecosystems.
{"title":"Variations of zooplankton community as bioindicators of eutrophication and water quality in shallow Yangtze Lakes","authors":"Jiangqianhui Qi , Yang Wang , Jing Yuan , Chuansong Liao , Jiashou Liu , Chuanbo Guo","doi":"10.1016/j.limno.2025.126248","DOIUrl":"10.1016/j.limno.2025.126248","url":null,"abstract":"<div><div>The Yangtze River and its adjacent lakes form a complex river-lake ecosystem, rich in aquatic biodiversity, with zooplankton serving as a key component. Zooplankton is important in nutrient circulation and energy flow, and also serves as an important indicator reflecting water quality and the overall health of aquatic ecosystems. Studying the changes in zooplankton community structure, which fluctuate with physicochemical environment, is crucial for understanding variations in lake water quality. We surveyed 15 shallow lakes of this river-lake ecosystem in the middle reaches of the Yangtze River. Using K-means cluster analysis based on the relative density ratios of Protozoa, Rotifera, Cladocera, and Copepoda, we classified the lakes into three distinct groups (Groups I to III). Our results showed a decline in the density and biomass proportions of Cladocera and Copepoda, contrasted by increases in those of Protozoa and Rotifera from Group I to III, alongside a rise in the Trophic Level Index, indicating progressive eutrophication. A composite diversity index, derived from the diversity indices of Shannon-Weiner, Pielou, and Margalef by using Principal Component Analysis, revealed an increase in diversity from Group I to III, suggesting a gradual stabilization of the community structure. Redundancy Analysis identified water temperature (WT), chlorophyll-a (Chl-a), secchi depth (SD), orthophosphates (PO<sub>4</sub><sup>3-</sup>), and dissolved oxygen (DO) as the primary environmental factors influencing zooplankton community structure. This study provides critical insights into the dynamics and environmental drivers of zooplankton community in these 15 lakes, offering a foundation for managing water eutrophication and facilitating the restoration of these aquatic ecosystems.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126248"},"PeriodicalIF":2.0,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-03-22DOI: 10.1016/j.limno.2025.126247
Hans-Peter Rusterholz, Bruno Baur
Intraspecific cryptic invasion involves the spread and establishment of non-native genetic lineages within the species’ native range. Individuals of non-native lineages can displace native individuals or hybridise with them. Hybridisation homogenises unique characteristics of geographically distinct populations and thus reduces the potential for future species diversity. In Europe, the freshwater snail Theodoxus fluviatilis has different haplotypes depending on the geographically separated water system. Since 2005, an upstream spread of T. fluviatilis with haplotype F31, which originates in the Ponto-Caspian region, has been recorded in the Danube and later in the river Rhine in Germany. Shortly after the invasion of snails with non-native haplotype, we collected 301 individuals of T. fluviatilis from 11 locations in the Upper and High Rhine. We used a mitochondrial marker (COI) for the determination of the snails’ haplotype: 19 individuals belonged to the native haplotype F28 (6.3 %), 159 (52.8 %) to the non-native haplotype F31 and 123 (40.9 %) to another non-native haplotype “euxinus” (also of Ponto-Caspian origin). Using eight microsatellites we examined whether individuals of the invading non-native haplotypes hybridise with individuals of the native haplotype F28. We found 12 hybrids (4.0 %) among the 301 snails examined. Hybrids occurred in 7 out of the 11 populations examined. We provide evidence that hybrids with the native haplotypes occur as early as the first 1–2 generations after the invasion of the non-native haplotypes. This indicates that the native haplotype of T. fluviatilis is unlikely to persist in the High Rhine in the long term.
{"title":"Cryptic invasion and intraspecific hybridisation in the freshwater snail Theodoxus fluviatilis in the river Rhine","authors":"Hans-Peter Rusterholz, Bruno Baur","doi":"10.1016/j.limno.2025.126247","DOIUrl":"10.1016/j.limno.2025.126247","url":null,"abstract":"<div><div>Intraspecific cryptic invasion involves the spread and establishment of non-native genetic lineages within the species’ native range. Individuals of non-native lineages can displace native individuals or hybridise with them. Hybridisation homogenises unique characteristics of geographically distinct populations and thus reduces the potential for future species diversity. In Europe, the freshwater snail <em>Theodoxus fluviatilis</em> has different haplotypes depending on the geographically separated water system. Since 2005, an upstream spread of <em>T. fluviatilis</em> with haplotype F31, which originates in the Ponto-Caspian region, has been recorded in the Danube and later in the river Rhine in Germany. Shortly after the invasion of snails with non-native haplotype, we collected 301 individuals of <em>T. fluviatilis</em> from 11 locations in the Upper and High Rhine. We used a mitochondrial marker (COI) for the determination of the snails’ haplotype: 19 individuals belonged to the native haplotype F28 (6.3 %), 159 (52.8 %) to the non-native haplotype F31 and 123 (40.9 %) to another non-native haplotype “euxinus” (also of Ponto-Caspian origin). Using eight microsatellites we examined whether individuals of the invading non-native haplotypes hybridise with individuals of the native haplotype F28. We found 12 hybrids (4.0 %) among the 301 snails examined. Hybrids occurred in 7 out of the 11 populations examined. We provide evidence that hybrids with the native haplotypes occur as early as the first 1–2 generations after the invasion of the non-native haplotypes. This indicates that the native haplotype of <em>T. fluviatilis</em> is unlikely to persist in the High Rhine in the long term.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126247"},"PeriodicalIF":2.0,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-03-20DOI: 10.1016/j.limno.2025.126246
Teresa Luftensteiner , Alcides Aybar Galdos , Markus Noack , Holger Schindler , Heide Stein , Hans Jürgen Hahn
Restoration of streams to a good ecological status, as required by the European Water Framework Directive (WFD), has been slow, if not failing. Colmation, the clogging of hyporheic interstices by fine sediments, could be one cause for this failure by negatively influencing hyporheic invertebrates. Therefore, this study analysed the hyporheic communities in six German rivers representing all five ecological status classes using ecological, colmation- and grain size analysis. The study revealed that I) the amount of fine sediment and level of colmation had a significant impact on the taxa number and the abundance of hyporheic meiofauna, II) increased colmation led to a shift from coarse- to fine sediment dweller-dominated hyporheic communities, III) hyporheic communities were impacted most by land use in catchments, fine sediment levels, and colmation, and IV) faunal patterns associated with colmation corresponded to the ‘general degradation’ classification defined by the WFD. Presumably elevated fine sediment loads from open land use types, and thereby increasing colmation-levels, altered the porosity and the size of voids. This led to a loss of habitats within the sediments which influenced hyporheic invertebrates. While substrate conditions are important for benthic communities, they are especially critical for hyporheic fauna, which responds particularly strongly to changes in sediment structure. Oxygen and nutrient provision are influenced by sediment structure and further impact the hyporheic organisms. Consequently, the loss of functioning communities led to the deterioration of the ecological status of rivers. Colmation should therefore be considered when implementing the WFD.
{"title":"It’s getting tight – How colmation influences the sediment fauna and why we might fail in restoring our streams","authors":"Teresa Luftensteiner , Alcides Aybar Galdos , Markus Noack , Holger Schindler , Heide Stein , Hans Jürgen Hahn","doi":"10.1016/j.limno.2025.126246","DOIUrl":"10.1016/j.limno.2025.126246","url":null,"abstract":"<div><div>Restoration of streams to a good ecological status, as required by the European Water Framework Directive (WFD), has been slow, if not failing. Colmation, the clogging of hyporheic interstices by fine sediments, could be one cause for this failure by negatively influencing hyporheic invertebrates. Therefore, this study analysed the hyporheic communities in six German rivers representing all five ecological status classes using ecological, colmation- and grain size analysis. The study revealed that I) the amount of fine sediment and level of colmation had a significant impact on the taxa number and the abundance of hyporheic meiofauna, II) increased colmation led to a shift from coarse- to fine sediment dweller-dominated hyporheic communities, III) hyporheic communities were impacted most by land use in catchments, fine sediment levels, and colmation, and IV) faunal patterns associated with colmation corresponded to the ‘general degradation’ classification defined by the WFD. Presumably elevated fine sediment loads from open land use types, and thereby increasing colmation-levels, altered the porosity and the size of voids. This led to a loss of habitats within the sediments which influenced hyporheic invertebrates. While substrate conditions are important for benthic communities, they are especially critical for hyporheic fauna, which responds particularly strongly to changes in sediment structure. Oxygen and nutrient provision are influenced by sediment structure and further impact the hyporheic organisms. Consequently, the loss of functioning communities led to the deterioration of the ecological status of rivers. Colmation should therefore be considered when implementing the WFD.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126246"},"PeriodicalIF":2.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2025-03-01DOI: 10.1016/j.limno.2025.126233
Maxime Sweetlove , Bjorn Tytgat , Evelien Van de Vyver , Elie Verleyen , Sofie D‘hondt , Dagmar Obbels , Moritz Buck , Roberto Urrutia , Stefan Bertilsson , Wim Vyverman
The effect of spatial factors reflecting dispersal potential between sites versus local environmental conditions on freshwater planktonic communities remains poorly understood. We assessed differences in the relative importance of local and seasonal environmental conditions versus spatial factors in explaining differences in community composition (i.e., beta-diversity patterns) in microbial plankton of 39 mid-latitude Chilean lakes spanning representative ecological gradients in altitude, mixing depth and water chemistry. The assemblages were taxonomically profiled by paired-end high throughput sequencing of the V3-V4 region of the 16S and the V4 region of the 18S rRNA genes. Variation partitioning analyses revealed that the explanatory power of environmental and seasonal factors versus spatial variables and their mutual overlap varied considerably among taxa and functional groups. More than 12 % of the variation in community structure was uniquely explained by environmental factors in the phytoplankton groups Dinophyta, Ochrophyta and Cyanobacteria, as well as in oligotrophic ultramicrobacteria, such as small rhodopsin containing Actinobacteria and LD12 Alphaproteobacteria. In phago-heterotrophic and saprotrophic groups, including heterotrophic micro-eukaryotes, and Bacteroidetes, environmental factors explained a smaller or even insignificant portion of the differences in the community structure. Our findings suggest that in Chilean lake microplankton, complex traits related to ecological and trophic strategy appear to affect the relative effect of local environmental properties on their community composition and hence the strength of species sorting along limnological gradients.
{"title":"Differences in community structuring among planktonic bacterial and micro-eukaryotic phyla in Chilean freshwater lakes","authors":"Maxime Sweetlove , Bjorn Tytgat , Evelien Van de Vyver , Elie Verleyen , Sofie D‘hondt , Dagmar Obbels , Moritz Buck , Roberto Urrutia , Stefan Bertilsson , Wim Vyverman","doi":"10.1016/j.limno.2025.126233","DOIUrl":"10.1016/j.limno.2025.126233","url":null,"abstract":"<div><div>The effect of spatial factors reflecting dispersal potential between sites versus local environmental conditions on freshwater planktonic communities remains poorly understood. We assessed differences in the relative importance of local and seasonal environmental conditions versus spatial factors in explaining differences in community composition (i.e., beta-diversity patterns) in microbial plankton of 39 mid-latitude Chilean lakes spanning representative ecological gradients in altitude, mixing depth and water chemistry. The assemblages were taxonomically profiled by paired-end high throughput sequencing of the V3-V4 region of the 16S and the V4 region of the 18S rRNA genes. Variation partitioning analyses revealed that the explanatory power of environmental and seasonal factors versus spatial variables and their mutual overlap varied considerably among taxa and functional groups. More than 12 % of the variation in community structure was uniquely explained by environmental factors in the phytoplankton groups Dinophyta, Ochrophyta and Cyanobacteria, as well as in oligotrophic ultramicrobacteria, such as small rhodopsin containing Actinobacteria and LD12 Alphaproteobacteria. In phago-heterotrophic and saprotrophic groups, including heterotrophic micro-eukaryotes, and Bacteroidetes, environmental factors explained a smaller or even insignificant portion of the differences in the community structure. Our findings suggest that in Chilean lake microplankton, complex traits related to ecological and trophic strategy appear to affect the relative effect of local environmental properties on their community composition and hence the strength of species sorting along limnological gradients.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"111 ","pages":"Article 126233"},"PeriodicalIF":2.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2025-02-28DOI: 10.1016/j.limno.2025.126236
Stéphane Tétard , Anthony Maire , Michaël Ovidio , Jean-Philippe Benitez , Frédéric Schaeffer , Marie Coll , Romain Roy
Movements of potamodromous fish are poorly understood, especially in large rivers, because studies often focus on fishway evaluation and diadromous species. Here, we assessed the movements of 808 fish of five potamodromous species (Barbel, Barbus barbus; Common bream, Abramis brama; Nase, Chondrostoma nasus; Asp, Leuciscus aspius and chub Squalius cephalus) over 14 years in a highly anthropized river system, the Rhine River, where hydropower plants were progressively equipped with fishways including RFID antennas. The objectives of the study were 1) to characterize long-term and large-scale individual movement patterns of five potamodromous fish species 2) to assess inter- and intra-specific variations based on quantitative movement metrics and 3) to create a typology of individuals based on their movements. Results showed that, despite high intra-specific variability, the inter-specific differences were strong enough to highlight long-term and large-scale species-specific behaviors. Breams exhibited movements that occurred essentially during spawning migration period and at the reach scale. In contrast, barbels were more active, with more movements outside their spawning migration period, showed more large-scale and downstream movements, and used navigation locks more often than other species. For this species, the maximum distance between the two furthest recorded positions at the basin scale was exceptionally high (max = 155 km). We conclude that potamodromous species undoubtedly perform large-scale movements, which are characterized by both species-specific and common features. Therefore, efforts need to be made to better consider their ecological needs and swimming capabilities when planning and designing effective fishways for the diverse range of species that move within river systems.
{"title":"Multi-year movements of potamodromous cyprinid species within a highly anthropized river assessed using RFID-equipped fishways","authors":"Stéphane Tétard , Anthony Maire , Michaël Ovidio , Jean-Philippe Benitez , Frédéric Schaeffer , Marie Coll , Romain Roy","doi":"10.1016/j.limno.2025.126236","DOIUrl":"10.1016/j.limno.2025.126236","url":null,"abstract":"<div><div>Movements of potamodromous fish are poorly understood, especially in large rivers, because studies often focus on fishway evaluation and diadromous species. Here, we assessed the movements of 808 fish of five potamodromous species (Barbel, <em>Barbus barbus</em>; Common bream, <em>Abramis brama</em>; Nase, <em>Chondrostoma nasus;</em> Asp, <em>Leuciscus aspius</em> and chub <em>Squalius cephalus</em>) over 14 years in a highly anthropized river system, the Rhine River, where hydropower plants were progressively equipped with fishways including RFID antennas. The objectives of the study were 1) to characterize long-term and large-scale individual movement patterns of five potamodromous fish species 2) to assess inter- and intra-specific variations based on quantitative movement metrics and 3) to create a typology of individuals based on their movements. Results showed that, despite high intra-specific variability, the inter-specific differences were strong enough to highlight long-term and large-scale species-specific behaviors. Breams exhibited movements that occurred essentially during spawning migration period and at the reach scale. In contrast, barbels were more active, with more movements outside their spawning migration period, showed more large-scale and downstream movements, and used navigation locks more often than other species. For this species, the maximum distance between the two furthest recorded positions at the basin scale was exceptionally high (max = 155 km). We conclude that potamodromous species undoubtedly perform large-scale movements, which are characterized by both species-specific and common features. Therefore, efforts need to be made to better consider their ecological needs and swimming capabilities when planning and designing effective fishways for the diverse range of species that move within river systems.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126236"},"PeriodicalIF":2.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2025-02-26DOI: 10.1016/j.limno.2025.126238
Eduardo Reyes-Grajales , Matteo Cazzanelli , Nora P. López-León , Alejandra Sepúlveda-Lozada , Luis Antonio Muñoz Alonso , Miriam Soria-Barreto , Rocío Rodiles-Hernández
Trophic ecology studies enhance our understanding of species relationships within communities and ecosystems, providing critical information for conservation programs targeting endangered species. The Central American river turtle (Dermatemys mawii) is one of the most critically endangered testudine species worldwide, yet its trophic ecology has been scarcely studied. Based on stable isotope analysis (δ13C and δ15N), we applied community-wide metrics and stable isotope mixing models to assess the intraspecific variation in the isotopic niche of D. mawii among different age and sex categories, its interspecific relationships with dominant fish species, and the relative contribution of basal resources to selected aquatic consumers in an oxbow lake in southern Mexico. The community-wide metrics suggested that D. mawii juveniles consumed a greater variety of food resources and/or had access to a wider variety of habitats than adults, regardless of sex. Through the mixing models we detected that the aquatic plant Pistia stratiotes was the main dietary source for adult females, while riparian plants were more important for juveniles and adult males, suggesting intraspecific niche partitioning. We also identified distinct energy pathways for D. mawii and fish, with turtles relying on vascular plants (both riparian and aquatic) while fish primarily depended on seston. Our findings suggest that D. mawii may play an important role in nutrient cycling and potentially regulate the presence of the free-floating macrophyte P. stratiotes at the study site.
{"title":"Stable isotope analysis reveals inter- and intraspecific trophic relationships of the endangered Central American river turtle in southern Mexico","authors":"Eduardo Reyes-Grajales , Matteo Cazzanelli , Nora P. López-León , Alejandra Sepúlveda-Lozada , Luis Antonio Muñoz Alonso , Miriam Soria-Barreto , Rocío Rodiles-Hernández","doi":"10.1016/j.limno.2025.126238","DOIUrl":"10.1016/j.limno.2025.126238","url":null,"abstract":"<div><div>Trophic ecology studies enhance our understanding of species relationships within communities and ecosystems, providing critical information for conservation programs targeting endangered species. The Central American river turtle (<em>Dermatemys mawii</em>) is one of the most critically endangered testudine species worldwide, yet its trophic ecology has been scarcely studied. Based on stable isotope analysis (<em>δ</em><sup>13</sup>C and <em>δ</em><sup>15</sup>N), we applied community-wide metrics and stable isotope mixing models to assess the intraspecific variation in the isotopic niche of <em>D. mawii</em> among different age and sex categories, its interspecific relationships with dominant fish species, and the relative contribution of basal resources to selected aquatic consumers in an oxbow lake in southern Mexico. The community-wide metrics suggested that <em>D. mawii</em> juveniles consumed a greater variety of food resources and/or had access to a wider variety of habitats than adults, regardless of sex. Through the mixing models we detected that the aquatic plant <em>Pistia stratiotes</em> was the main dietary source for adult females, while riparian plants were more important for juveniles and adult males, suggesting intraspecific niche partitioning. We also identified distinct energy pathways for <em>D. mawii</em> and fish, with turtles relying on vascular plants (both riparian and aquatic) while fish primarily depended on seston. Our findings suggest that <em>D. mawii</em> may play an important role in nutrient cycling and potentially regulate the presence of the free-floating macrophyte <em>P. stratiotes</em> at the study site.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"112 ","pages":"Article 126238"},"PeriodicalIF":2.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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