Pub Date : 2025-11-01Epub Date: 2025-09-17DOI: 10.1016/j.limno.2025.126291
Noah Bohl , Michael R. Twiss , Diana T. White
We describe an approach to measure the invasiveness of Myriophyllum heterophyllum (variable leaf watermilfoil) in a shallow dystrophic impoundment at the early stages of an invasion. Over an eight-week observation period, dry weight measurements show a biomass specific rate growth rate of 0.0048·day−1, consistent with other studies of invasive watermilfoil growth, and a diffusion rate (biomass spread) of D = 9.2 cm2·d−1, which describes the horizontal encroachment into plant-free sediment.
{"title":"A technique to monitor growth and spread of early-stage variable-leaf watermilfoil in a shallow impoundment","authors":"Noah Bohl , Michael R. Twiss , Diana T. White","doi":"10.1016/j.limno.2025.126291","DOIUrl":"10.1016/j.limno.2025.126291","url":null,"abstract":"<div><div>We describe an approach to measure the invasiveness of <em>Myriophyllum heterophyllum</em> (variable leaf watermilfoil) in a shallow dystrophic impoundment at the early stages of an invasion. Over an eight-week observation period, dry weight measurements show a biomass specific rate growth rate of 0.0048·day<sup>−1</sup>, consistent with other studies of invasive watermilfoil growth, and a diffusion rate (biomass spread) of D = 9.2 cm<sup>2</sup>·d<sup>−1</sup>, which describes the horizontal encroachment into plant-free sediment.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126291"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097893","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 : 2025-11-01Epub Date: 2025-11-05DOI: 10.1016/j.limno.2025.126295
Alan Santiago Tarda , Mario Carlos Nazareno Saparrat , Delia Elena Bauer , Nora Gómez
The aim of this study was to evaluate the decomposition of Typha latifolia leaf fragments, characterize the fungal assemblages, and examine their relationship with β-glucosidase activity over a period of 216 days in two riverine wetlands of the Pampean Plain, Argentina, with contrasting hydrological regimes. Decomposition rates were k = 0.004 day⁻¹ and k = 0.002 day⁻¹ in the Chubichaminí and Del Gato wetlands, respectively, with 40 % and 60 % of the initial leaf mass remaining at the end of the experiment. β-Glucosidase activity peaked at day 80 in both wetlands, coinciding with an increase in sporulation rates and fungal taxonomic richness. A total of 38 Ingoldian taxa were identified. Dictyochaeta triseptata and Tetracladium breve were typical of Chubichaminí, while Sigmoidea prolifera and Fibulotaeniella sp. were typical of Del Gato at the beginning of decomposition. Amniculicola longissima became dominant towards the end in both wetlands. In Chubichaminí, spore morphology shifted from predominantly radiate forms at the beginning to filiform types later, whereas in Del Gato, filiform spores remained dominant throughout. T. latifolia decomposition, linked to β-glucosidase activity and fungal community structure, is strongly influenced by hydrological conditions in riverine wetlands. This integrative approach enhances our understanding of wetland functioning and provides insights for adaptive management under climate change and anthropogenic pressures.
{"title":"Colonization and activity of aquatic fungi during the decomposition of Typha latifolia leaf fragments under contrasting hydrological regimes","authors":"Alan Santiago Tarda , Mario Carlos Nazareno Saparrat , Delia Elena Bauer , Nora Gómez","doi":"10.1016/j.limno.2025.126295","DOIUrl":"10.1016/j.limno.2025.126295","url":null,"abstract":"<div><div>The aim of this study was to evaluate the decomposition of <em>Typha latifolia</em> leaf fragments, characterize the fungal assemblages, and examine their relationship with β-glucosidase activity over a period of 216 days in two riverine wetlands of the Pampean Plain, Argentina, with contrasting hydrological regimes. Decomposition rates were k = 0.004 day⁻¹ and k = 0.002 day⁻¹ in the Chubichaminí and Del Gato wetlands, respectively, with 40 % and 60 % of the initial leaf mass remaining at the end of the experiment. β-Glucosidase activity peaked at day 80 in both wetlands, coinciding with an increase in sporulation rates and fungal taxonomic richness. A total of 38 Ingoldian taxa were identified<em>. Dictyochaeta triseptata</em> and <em>Tetracladium breve</em> were typical of Chubichaminí, while <em>Sigmoidea prolifera</em> and <em>Fibulotaeniella</em> sp. were typical of Del Gato at the beginning of decomposition. <em>Amniculicola longissima</em> became dominant towards the end in both wetlands. In Chubichaminí, spore morphology shifted from predominantly radiate forms at the beginning to filiform types later, whereas in Del Gato, filiform spores remained dominant throughout. <em>T. latifolia</em> decomposition, linked to β-glucosidase activity and fungal community structure, is strongly influenced by hydrological conditions in riverine wetlands. This integrative approach enhances our understanding of wetland functioning and provides insights for adaptive management under climate change and anthropogenic pressures.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126295"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145519537","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 : 2025-11-01Epub Date: 2025-09-09DOI: 10.1016/j.limno.2025.126283
Abuzer Çelekli
Lakes are increasingly vulnerable to anthropogenic pressures such as pollution, eutrophication, and climate change, leading to biodiversity loss and ecosystem degradation. This study employed phytoplankton-based metrics across two hydrological periods to evaluate species-environment interactions and assess the ecological status of thirteen lakes in the Lake Van Basin. Canonical correspondence analysis (CCA) showed a strong correlation (96.7 %) between phytoplankton assemblages and environmental stressors. The most influential factors affecting phytoplankton distribution were conductivity, total organic carbon, total suspended solids, total phosphorus, total nitrogen, and nitrate. The CCA clearly distinguished the soda lakes, Lakes Erçek and Sodalı, which were characterized by high conductivity, alkaline pH, and high total organic carbon, and hosted assemblages dominated by taxa tolerant to organic pollution and salinity. In contrast, Lake Hıdırmenteş supported phytoplankton communities adapted to elevated nutrient and turbidity levels, while the Ahlat Marshes were associated with species indicative of nitrogen enrichment. The MPTI−modified phytoplankton trophic index proved to be an effective tool for ecological assessment, showing a strong correlation with total phosphorus (r = 0.925, p < 0.01). The MPTI indicated that Lakes Nemrut, Aygır, and Nazik had a high ecological status, whereas Lakes Erçek, Hıdırmenteş, and Adırum showed a poor status and Lakes Turna and Hasantimur had a moderate one. This first eco-assessment of the region underscores the value of phytoplankton as sensitive indicators of environmental stress and supports the application of the MPTI for ecological status classification in saline and freshwater lakes of the Lake Van Basin.
{"title":"The first eco-assessment of thirteen lakes in the Lake Van Basin of Türkiye with phytoplankton metrics as indicators of environmental conditions","authors":"Abuzer Çelekli","doi":"10.1016/j.limno.2025.126283","DOIUrl":"10.1016/j.limno.2025.126283","url":null,"abstract":"<div><div>Lakes are increasingly vulnerable to anthropogenic pressures such as pollution, eutrophication, and climate change, leading to biodiversity loss and ecosystem degradation. This study employed phytoplankton-based metrics across two hydrological periods to evaluate species-environment interactions and assess the ecological status of thirteen lakes in the Lake Van Basin. Canonical correspondence analysis (CCA) showed a strong correlation (96.7 %) between phytoplankton assemblages and environmental stressors. The most influential factors affecting phytoplankton distribution were conductivity, total organic carbon, total suspended solids, total phosphorus, total nitrogen, and nitrate. The CCA clearly distinguished the soda lakes, Lakes Erçek and Sodalı, which were characterized by high conductivity, alkaline pH, and high total organic carbon, and hosted assemblages dominated by taxa tolerant to organic pollution and salinity. In contrast, Lake Hıdırmenteş supported phytoplankton communities adapted to elevated nutrient and turbidity levels, while the Ahlat Marshes were associated with species indicative of nitrogen enrichment<em>.</em> The MPTI−modified phytoplankton trophic index proved to be an effective tool for ecological assessment, showing a strong correlation with total phosphorus (r = 0.925, p < 0.01). The MPTI indicated that Lakes Nemrut, Aygır, and Nazik had a high ecological status, whereas Lakes Erçek, Hıdırmenteş, and Adırum showed a poor status and Lakes Turna and Hasantimur had a moderate one. This first eco-assessment of the region underscores the value of phytoplankton as sensitive indicators of environmental stress and supports the application of the MPTI for ecological status classification in saline and freshwater lakes of the Lake Van Basin.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126283"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050224","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 : 2025-11-01Epub Date: 2025-10-08DOI: 10.1016/j.limno.2025.126294
Wenjuan Song , Nana Xue , Yuyi Yang , Geoffrey Michael Gadd
Desert inland rivers play crucial role in water resource supply and ecosystem maintenance. The composition and structure of microbial especially bacterial communities have important effects on water environment quality and ecological function. In this study, the composition, assembly mechanisms and co-occurrence network of bacterial communities were studied in Tarim River, the largest inland desert river in China. The research found significant differences in α-diversity and β-diversity between abundant and rare taxa across free-living and particle-associated bacteria. Pseudomonadota dominated bacterial communities, and the abundant taxa and rare taxa of both free-living and particle-associated showed a high variation of percentages. Verrucomicrobiota enriched in the abundant taxa of particle-associated bacteria. TOC, TN and NO3-N had significant correlation with the composition of rare, total and abundant taxa of both free-living and particle-associated bacteria, while TP also had significant correlation with the composition of rare taxa of free-living bacteria. Total taxa in both free-living and particle-associated bacteria were more fitted by neutral model and influenced by stochastic processes, while the rare and abundant taxa were less influenced by stochastic processes. Furthermore, the co-occurrence network analysis revealed that rare taxa could serve as critical connectors and module hubs in free-living bacteria, compared to particle-associated bacteria. Overall, our study highlights the distinctive roles of abundant taxa and rare taxa in bacterial community assembly and ecosystem function in desert river ecosystems. Understanding these roles is essential for developing conservation strategies aimed at preserving microbial diversity and sustaining ecosystem services in vulnerable habitats.
{"title":"Microbial communities of desert river: Distinct roles of abundant and rare bacteria in the Tarim River ecosystem","authors":"Wenjuan Song , Nana Xue , Yuyi Yang , Geoffrey Michael Gadd","doi":"10.1016/j.limno.2025.126294","DOIUrl":"10.1016/j.limno.2025.126294","url":null,"abstract":"<div><div>Desert inland rivers play crucial role in water resource supply and ecosystem maintenance. The composition and structure of microbial especially bacterial communities have important effects on water environment quality and ecological function. In this study, the composition, assembly mechanisms and co-occurrence network of bacterial communities were studied in Tarim River, the largest inland desert river in China. The research found significant differences in α-diversity and β-diversity between abundant and rare taxa across free-living and particle-associated bacteria. <em>Pseudomonadota</em> dominated bacterial communities, and the abundant taxa and rare taxa of both free-living and particle-associated showed a high variation of percentages. <em>Verrucomicrobiota</em> enriched in the abundant taxa of particle-associated bacteria. TOC, TN and NO<sub>3</sub>-N had significant correlation with the composition of rare, total and abundant taxa of both free-living and particle-associated bacteria, while TP also had significant correlation with the composition of rare taxa of free-living bacteria. Total taxa in both free-living and particle-associated bacteria were more fitted by neutral model and influenced by stochastic processes, while the rare and abundant taxa were less influenced by stochastic processes. Furthermore, the co-occurrence network analysis revealed that rare taxa could serve as critical connectors and module hubs in free-living bacteria, compared to particle-associated bacteria. Overall, our study highlights the distinctive roles of abundant taxa and rare taxa in bacterial community assembly and ecosystem function in desert river ecosystems. Understanding these roles is essential for developing conservation strategies aimed at preserving microbial diversity and sustaining ecosystem services in vulnerable habitats.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126294"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268984","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 : 2025-11-01Epub Date: 2025-09-18DOI: 10.1016/j.limno.2025.126292
Wen Zhang , Wenxi Pan , Qin You , Ningtao Wang
This study develops a framework to optimize the selection of phosphorus release risk indices (PRRIs) for river sediments, based on key physicochemical properties—organic matter (OM), redox potential (Eh), and the CDB-P/Ca-P ratio (ROP). To address variability in PRRI applicability across sediment types, sediments from six rivers in China’s Sichuan Basin were analyzed. Results show that universal indices—including the Eutrophication Risk Index (ERI), Soil Phosphorus Storage Capacity (SPSC), Degree of Phosphorus Saturation (DPS), and Phosphorus Sorption Index (PSI)—exhibit strong, significant correlations with phosphorus release fluxes across all sediment categories (r = 0.71–0.89, p < 0.01). Sediment classification further improves prediction accuracy: ERI and PSI perform best in OM-rich sediments (OM-1), where organic matter drives adsorption-desorption processes; Non-apatite inorganic P (NAIP) and Water-Soluble P (WSP) are reliable indicators in CDB-P-dominated systems (ROP-1); ERI is prioritized in weakly reducing sediments (Eh-2) (r = 0.90); and DPS, alongside Equilibrium P Concentration at net zero sorption (EPC₀), is more applicable in Ca-P-dominated sediments (ROP-2). This framework balances assessment accuracy and operational feasibility, offering actionable guidance for precise phosphorus release risk evaluation and targeted watershed management.
{"title":"Optimizing phosphorus release risk index based on river sediment physicochemical properties","authors":"Wen Zhang , Wenxi Pan , Qin You , Ningtao Wang","doi":"10.1016/j.limno.2025.126292","DOIUrl":"10.1016/j.limno.2025.126292","url":null,"abstract":"<div><div>This study develops a framework to optimize the selection of phosphorus release risk indices (PRRIs) for river sediments, based on key physicochemical properties—organic matter (OM), redox potential (Eh), and the CDB-P/Ca-P ratio (ROP). To address variability in PRRI applicability across sediment types, sediments from six rivers in China’s Sichuan Basin were analyzed. Results show that universal indices—including the Eutrophication Risk Index (ERI), Soil Phosphorus Storage Capacity (SPSC), Degree of Phosphorus Saturation (DPS), and Phosphorus Sorption Index (PSI)—exhibit strong, significant correlations with phosphorus release fluxes across all sediment categories (r = 0.71–0.89, <em>p</em> < 0.01). Sediment classification further improves prediction accuracy: ERI and PSI perform best in OM-rich sediments (OM-1), where organic matter drives adsorption-desorption processes; Non-apatite inorganic P (NAIP) and Water-Soluble P (WSP) are reliable indicators in CDB-P-dominated systems (ROP-1); ERI is prioritized in weakly reducing sediments (Eh-2) (r = 0.90); and DPS, alongside Equilibrium P Concentration at net zero sorption (EPC₀), is more applicable in Ca-P-dominated sediments (ROP-2). This framework balances assessment accuracy and operational feasibility, offering actionable guidance for precise phosphorus release risk evaluation and targeted watershed management.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126292"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145119473","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 : 2025-11-01Epub Date: 2025-10-06DOI: 10.1016/j.limno.2025.126293
Evan M. Bredeweg , Ivan Arismendi , Christina A. Murphy , Sarah K. Henkel
Floating photovoltaic (FPV) systems are emerging as a promising strategy for large-scale clean energy production worldwide. However, by altering key physical drivers such as solar radiation and wind mixing, FPV installations may have also unintended consequences for lakes and reservoirs. Given the wide diversity of freshwater systems globally, understanding the consistency in direction and magnitude of environmental responses to FPV deployment is critical for informed regulatory oversight and sustainable energy development. Here, we used process-based models to simulate the effects of FPV coverage on 11 reservoirs across the United States. This is the first multi-reservoir analysis using a laterally averaged 2D process-based modeling framework to systematically evaluate FPV impacts across diverse climatic and morphometric contexts, enabling direct comparison of magnitude and direction of responses among systems. Specifically, we evaluated changes in (1) surface and outflow temperature, (2) thermocline depth, (3) water column stability, (4) dissolved oxygen concentrations, and (5) potential suitable habitat availability for warm- and cold-water fishes. We quantified changes in these response variables by an iterative approach that simulates increases in FPV coverage and compares them with reference conditions. We summarized responses for winter (January–February) and summer (July–August). As expected, our simulations show that increasing FPV coverage consistently cooled surface waters and altered thermal stratification patterns, but the magnitude and environmental implications of these changes varied among reservoirs. Notably, greater FPV coverage led to increased variability in habitat suitability for aquatic species, with some reservoirs exhibiting distinct and sometimes divergent responses. These findings underscore the importance of considering local environmental contexts when assessing FPV impacts. While large-scale FPV systems offer potential benefits for climate mitigation, their ecological effects, particularly on thermally sensitive biota, require careful site-specific evaluation to avoid unintended consequences to local freshwater biodiversity.
{"title":"Modeling diverse environmental responses of reservoirs to floating photovoltaic systems","authors":"Evan M. Bredeweg , Ivan Arismendi , Christina A. Murphy , Sarah K. Henkel","doi":"10.1016/j.limno.2025.126293","DOIUrl":"10.1016/j.limno.2025.126293","url":null,"abstract":"<div><div>Floating photovoltaic (FPV) systems are emerging as a promising strategy for large-scale clean energy production worldwide. However, by altering key physical drivers such as solar radiation and wind mixing, FPV installations may have also unintended consequences for lakes and reservoirs. Given the wide diversity of freshwater systems globally, understanding the consistency in direction and magnitude of environmental responses to FPV deployment is critical for informed regulatory oversight and sustainable energy development. Here, we used process-based models to simulate the effects of FPV coverage on 11 reservoirs across the United States. This is the first multi-reservoir analysis using a laterally averaged 2D process-based modeling framework to systematically evaluate FPV impacts across diverse climatic and morphometric contexts, enabling direct comparison of magnitude and direction of responses among systems. Specifically, we evaluated changes in (1) surface and outflow temperature, (2) thermocline depth, (3) water column stability, (4) dissolved oxygen concentrations, and (5) potential suitable habitat availability for warm- and cold-water fishes. We quantified changes in these response variables by an iterative approach that simulates increases in FPV coverage and compares them with reference conditions. We summarized responses for winter (January–February) and summer (July–August). As expected, our simulations show that increasing FPV coverage consistently cooled surface waters and altered thermal stratification patterns, but the magnitude and environmental implications of these changes varied among reservoirs. Notably, greater FPV coverage led to increased variability in habitat suitability for aquatic species, with some reservoirs exhibiting distinct and sometimes divergent responses. These findings underscore the importance of considering local environmental contexts when assessing FPV impacts. While large-scale FPV systems offer potential benefits for climate mitigation, their ecological effects, particularly on thermally sensitive biota, require careful site-specific evaluation to avoid unintended consequences to local freshwater biodiversity.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126293"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268489","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 : 2025-11-01Epub Date: 2025-09-06DOI: 10.1016/j.limno.2025.126282
Patricia E. Garcia , Maria V. Castro , María C. Maluendez Testoni , Patricia Rodríguez
Dissolved organic matter (DOM) is a crucial component of the global carbon cycle, significantly influencing aquatic ecosystems through its quantity and quality, which are shaped by abiotic factors such as precipitation, runoff, and solar radiation. Recently, the role of winter conditions, particularly ice cover, has gained attention due to the ongoing biogeochemical processes that occur during this period. This study explores the effect of winter precipitations on DOM dynamics in humic shallow lakes and beaver ponds in Tierra del Fuego over two consecutive years. Higher accumulated precipitation in 2021 compared to 2022 led to differences in DOM properties. While dissolved organic carbon (DOC) levels were higher in 2022, likely due to concentration effects from reduced precipitation, shallow lakes and beaver ponds exhibited distinct responses. Absorbance-based (water color, SUVA and spectral slope) assessments revealed a slight increase in DOM molecular size in shallow lakes during 2022, whereas fluorescence-based indices (HIX and BIX) indicated greater humification in 2021 but fewer humic components, suggesting complex patterns of allochthonous DOM mobilization. These findings highlight the importance of precipitation regimes and runoff in shaping DOM dynamics in subantarctic aquatic systems, with significant contribution from the surrounding soils and vegetation.
{"title":"Interannual variability in dissolved organic matter (DOM) concentration and quality in shallow water bodies of Tierra del Fuego (Argentina)","authors":"Patricia E. Garcia , Maria V. Castro , María C. Maluendez Testoni , Patricia Rodríguez","doi":"10.1016/j.limno.2025.126282","DOIUrl":"10.1016/j.limno.2025.126282","url":null,"abstract":"<div><div>Dissolved organic matter (DOM) is a crucial component of the global carbon cycle, significantly influencing aquatic ecosystems through its quantity and quality, which are shaped by abiotic factors such as precipitation, runoff, and solar radiation. Recently, the role of winter conditions, particularly ice cover, has gained attention due to the ongoing biogeochemical processes that occur during this period. This study explores the effect of winter precipitations on DOM dynamics in humic shallow lakes and beaver ponds in Tierra del Fuego over two consecutive years. Higher accumulated precipitation in 2021 compared to 2022 led to differences in DOM properties. While dissolved organic carbon (DOC) levels were higher in 2022, likely due to concentration effects from reduced precipitation, shallow lakes and beaver ponds exhibited distinct responses. Absorbance-based (water color, SUVA and spectral slope) assessments revealed a slight increase in DOM molecular size in shallow lakes during 2022, whereas fluorescence-based indices (HIX and BIX) indicated greater humification in 2021 but fewer humic components, suggesting complex patterns of allochthonous DOM mobilization. These findings highlight the importance of precipitation regimes and runoff in shaping DOM dynamics in subantarctic aquatic systems, with significant contribution from the surrounding soils and vegetation.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"115 ","pages":"Article 126282"},"PeriodicalIF":2.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027735","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 : 2025-11-01Epub Date: 2025-11-12DOI: 10.1016/j.limno.2025.126296
Sara Lodi , Cláudia Felix de Almeida , Bruno Spacek Godoy , Daniel de Paiva Silva
Spatial synchrony, defined as the temporal correlation between population fluctuations across different locations, is crucial for understanding the dynamics of ecological communities, especially aquatic ecosystems. Although well studied in temperate systems, the influence of taxonomic resolution on the detection of spatial synchrony remains poorly explored in tropical reservoirs. Here, we investigated the synchrony patterns of the zooplankton community in the tropical Serra do Facão reservoir, located in the Paraná River basin (GO, Brazil), considering limnological, climatic, and operational variables. While overall spatial synchrony was low, we identified a complex geography of synchrony that was significantly associated with local environmental drivers, such as physical and productivity-related variables, for specific taxa. Physical and productivity-related variables correlated with the synchrony of particular taxa (e.g., Daphnia gessneri and Diaphanosoma sp.), whereas climatic and operational factors did not exhibit a significant influence. These findings contrast with studies in temperate reservoirs, suggesting that intrinsic environmental heterogeneity and anthropogenic management suppress broad synchrony patterns. Our results highlight the importance of monitoring local variables in conservation programs for tropical reservoirs and question the effectiveness of approaches based on broad taxonomic groups in detecting synchronized responses. This study provides valuable insights into the sustainable management of aquatic ecosystems under anthropogenic pressure, emphasizing the need for research on larger spatial scales and the consideration of trophic variables to fully comprehend the dynamics of these systems.
空间同步性被定义为不同地点种群波动之间的时间相关性，对于理解生态群落，特别是水生生态系统的动态至关重要。虽然在温带系统中已经有了很好的研究，但在热带水库中，分类分辨率对空间同步检测的影响还没有得到充分的探讨。本文研究了位于巴西帕拉纳河流域的热带Serra do fac水库浮游动物群落的同步模式，考虑了湖泊、气候和操作变量。虽然整体空间同步性较低，但我们发现了一个复杂的地理同步性，它与特定分类群的本地环境驱动因素（如物理和生产力相关变量）显著相关。物理和生产力相关变量与特定分类群的同步性相关（如水蚤和水蚤），而气候和操作因素没有表现出显著的影响。这些发现与温带水库的研究结果相反，表明内在的环境异质性和人为管理抑制了广泛的同步模式。我们的研究结果强调了监测热带水库保护计划中局部变量的重要性，并质疑了基于广泛分类群的方法在检测同步响应方面的有效性。该研究为人为压力下水生生态系统的可持续管理提供了有价值的见解，强调需要在更大的空间尺度上进行研究，并考虑营养变量，以充分理解这些系统的动态。
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Pub Date : 2025-09-01Epub Date: 2025-08-22DOI: 10.1016/j.limno.2025.126279
Nora Meyer , Matthias Kunz , Roman Mathias Link , Goddert von Oheimb
Swimming in lakes and spending time on the shore are popular summer activities, but as climate change continues and land use intensifies, pressure on lakeshore ecosystems is increasing. In particular, plants play an important role in these ecosystems by stabilizing the shoreline and providing habitat, but they suffer from trampling and destruction caused by human use. However, the effects of lakeshore recreation on plants are not well understood. To assess the impact of bathers on the reed bed and the area of the shoreline used for sunbathing, terrestrial laser scanning (TLS) was employed to analyze changes in the aboveground spatial distribution of plant material at very high spatial or temporal resolution. Measurements were taken before and after summer weekends at nine lakes in Brandenburg, Germany, and the occupancy status of voxels (i.e., cubic volume elements) in voxelized TLS point clouds of the lakeshore vegetation was compared. In addition, standardized visitor counts were conducted to determine the bathing sites' visitation rates. Over the course of a summer weekend, bathing and control sites displayed similar changes in total reed volume. The analysis has identified no clear relationship between the highly dynamic volume changes and the bathing activity along the gradient of visitor density that has been considered here. The variation of vegetation in the sunbathing area was generally small and showed no clear tendency for directed loss or gain after a weekend. As we studied established sites, the vegetation may have already adapted to human use. While the current visitor density and visitor behavior do not appear to be causing discernible changes, visitor management measures will be necessary if the intensity of use increases in the future.
{"title":"Reed between the lines: Terrestrial 3D laser scanning to assess recreational impacts on lakeshore vegetation","authors":"Nora Meyer , Matthias Kunz , Roman Mathias Link , Goddert von Oheimb","doi":"10.1016/j.limno.2025.126279","DOIUrl":"10.1016/j.limno.2025.126279","url":null,"abstract":"<div><div>Swimming in lakes and spending time on the shore are popular summer activities, but as climate change continues and land use intensifies, pressure on lakeshore ecosystems is increasing. In particular, plants play an important role in these ecosystems by stabilizing the shoreline and providing habitat, but they suffer from trampling and destruction caused by human use. However, the effects of lakeshore recreation on plants are not well understood. To assess the impact of bathers on the reed bed and the area of the shoreline used for sunbathing, terrestrial laser scanning (TLS) was employed to analyze changes in the aboveground spatial distribution of plant material at very high spatial or temporal resolution. Measurements were taken before and after summer weekends at nine lakes in Brandenburg, Germany, and the occupancy status of voxels (i.e., cubic volume elements) in voxelized TLS point clouds of the lakeshore vegetation was compared. In addition, standardized visitor counts were conducted to determine the bathing sites' visitation rates. Over the course of a summer weekend, bathing and control sites displayed similar changes in total reed volume. The analysis has identified no clear relationship between the highly dynamic volume changes and the bathing activity along the gradient of visitor density that has been considered here. The variation of vegetation in the sunbathing area was generally small and showed no clear tendency for directed loss or gain after a weekend. As we studied established sites, the vegetation may have already adapted to human use. While the current visitor density and visitor behavior do not appear to be causing discernible changes, visitor management measures will be necessary if the intensity of use increases in the future.</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"114 ","pages":"Article 126279"},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902326","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 : 2025-09-01Epub Date: 2025-07-15DOI: 10.1016/j.limno.2025.126267
L.A. Morales-Marín , J.R. French , K.E. Lindenschmidt
Although lakes are generally considered to function as long-term sediment sinks, remobilisation of bottom sediments can be significant and has implications for water quality and palaeoenvironmental analysis of lake sediment records. Wind-waves and wind-generated currents are the most important drivers of sediment resuspension but the complexity of their interaction and their intermittent nature complicate direct observation of these processes. This paper demonstrates a hybrid approach that combines a three-dimensional (3D) community hydrodynamic model (FVCOM) with a parameterised fetch-limited wind wave model to simulate the relative proportions of the lake bed subject to sediment resuspension under different meteorological conditions. Model validation and testing is undertaken for a small upland lake exposed to strong wind forcing. A series of exploratory model experiments indicate the dominance of wind-wave stresses over flow current stresses for wind speed 12 m s. Accordingly, the ratio between wind-wave stresses and current stresses can be around 15 for low wind speeds, but this ratio tends non-linearly to 1 when wind speed increases because of the faster growth of current stresses. The analysis of wind direction scenarios under typical wind speed conditions indicate that wind waves would resuspend sediments over narrow downwind zones along the shores. At different depth ranges, wind-waves are only able to resuspend sediments in areas less than about 5 m in depth, whereas for current-induced stresses, the resuspended area is more extensive for intermediate depths (from 5 m to 15 m).
虽然湖泊通常被认为是长期的沉积物汇，但底部沉积物的再动员可能是重要的，并对水质和湖泊沉积物记录的古环境分析产生影响。风浪和风生海流是沉积物再悬浮最重要的驱动因素，但它们相互作用的复杂性及其间歇性使对这些过程的直接观测复杂化。本文介绍了一种将三维群落水动力模型（FVCOM）与参数化提取限制风波模型相结合的混合方法，以模拟不同气象条件下沉积物再悬浮对湖床相对比例的影响。对一个受强风影响的小型高原湖泊进行了模型验证和试验。一系列探索性模型实验表明，风速≤12 m s−1时，风波应力优于水流应力。因此，在低风速条件下，风波应力与电流应力之比可以在15左右，但当风速增大时，由于电流应力增长较快，该比值非线性地趋于1。在典型风速条件下的风向情景分析表明，风浪会使沿海岸的狭窄下风带的沉积物重悬。在不同的深度范围内，风浪只能在深度小于5 m的区域对沉积物进行再悬浮，而对于水流应力，在中间深度（5 ~ 15 m）对沉积物的再悬浮区域更为广泛。
{"title":"Exploratory modelling of wind-generated wave and current bottom stress and potential for sediment resuspension in small lakes","authors":"L.A. Morales-Marín , J.R. French , K.E. Lindenschmidt","doi":"10.1016/j.limno.2025.126267","DOIUrl":"10.1016/j.limno.2025.126267","url":null,"abstract":"<div><div>Although lakes are generally considered to function as long-term sediment sinks, remobilisation of bottom sediments can be significant and has implications for water quality and palaeoenvironmental analysis of lake sediment records. Wind-waves and wind-generated currents are the most important drivers of sediment resuspension but the complexity of their interaction and their intermittent nature complicate direct observation of these processes. This paper demonstrates a hybrid approach that combines a three-dimensional (3D) community hydrodynamic model (FVCOM) with a parameterised fetch-limited wind wave model to simulate the relative proportions of the lake bed subject to sediment resuspension under different meteorological conditions. Model validation and testing is undertaken for a small upland lake exposed to strong wind forcing. A series of exploratory model experiments indicate the dominance of wind-wave stresses over flow current stresses for wind speed <span><math><mo>≤</mo></math></span> 12 m s<span><math><mrow><msup><mrow></mrow><mrow><mo>−</mo></mrow></msup><mn>1</mn></mrow></math></span>. Accordingly, the ratio between wind-wave stresses and current stresses can be around 15 for low wind speeds, but this ratio tends non-linearly to 1 when wind speed increases because of the faster growth of current stresses. The analysis of wind direction scenarios under typical wind speed conditions indicate that wind waves would resuspend sediments over narrow downwind zones along the shores. At different depth ranges, wind-waves are only able to resuspend sediments in areas less than about 5 m in depth, whereas for current-induced stresses, the resuspended area is more extensive for intermediate depths (from 5 m to 15 m).</div></div>","PeriodicalId":51110,"journal":{"name":"Limnologica","volume":"114 ","pages":"Article 126267"},"PeriodicalIF":2.0,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656931","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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