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Bioenergetics models are powerful tools used to address a range of questions in fish biology. However, these models are rarely informed by free‐swimming activity data, introducing error. To quantify the costs of activity in free‐swimming fish, calibrations produced from standardized laboratory trials can be applied to estimate energy expenditure from sensor data for specific tags and species. Using swim tunnel respirometry, we calibrated acceleration sensor‐equipped transmitting tags to estimate the aerobic metabolic rates (ṀO2) of lake trout (Salvelinus namaycush) at three environmentally relevant temperatures. Aerobic and swim performance were also assessed. Like other calibrations, we found strong relationships between ṀO2 and acceleration or swimming speed, and jackknife validations and data simulations suggest that our models accurately predict metabolic costs of activity in adult lake trout (~5% algebraic error and ~20% absolute error). Aerobic and swim performance metrics were similar to those reported in other studies, but their critical swimming speed was lower than expected. Additionally, lake trout exhibited a wide aerobic scope, suggesting that the avoidance of waters ≥15°C may be related to selection for optimal growing temperatures. The ability to quantify the free‐swimming energetic costs of activity will advance our understanding of lake trout ecology and may yield improvements to bioenergetics model. [ABSTRACT FROM AUTHOR]

Submerged macrophytes are important indicators of the state of shallow freshwater ecosystems. Reconstruction long‐term changes in submerged macrophytes remains a challenge in paleoecology. Here, the relative biomass (mass weight) of different plants to sedimentary organic matter in a shallow lake in central China was estimated using a Bayesian multi‐source mixing model with concentrations and δ13C of n‐alkanes extracted from surface lake sediments. The spatial distribution of submerged macrophytes biomass estimated by the model correlates with water transparency, water depth, and total nitrogen. The correlation patterns are consistent with previously established patterns of submerged macrophyte growth and water conditions, which supports the utility of the Bayesian approach in shallow freshwater lakes. In comparison, Paq, proportion of mid‐chain length (C23, C25) to long‐chain length (C29, C31) homologs, underestimated the contribution of submerged macrophytes, especially in samples with moderate Paq values (0.3 < Paq < 0.4). On the other hand, some discrepancies between the model output and the satellite imagery estimated macrophyte coverage are present, which suggests that ground‐truthing is needed to further evaluate this approach. Our study demonstrates that the Bayesian mixing model combining the abundance and isotopes of n‐alkanes makes a reasonable estimation of the relative biomass of submerged macrophytes in the sediments. This approach provides new insights into reconstructing long‐term variations in submerged macrophytes for paleoecological studies, which is valuable for the restoration and conservation of shallow freshwater lakes when long‐term limnological monitoring is lacking. Plain Language Summary: Long‐term records of submerged macrophytes are critical for studies of lake ecology and climate of the past, as well as the restoration of freshwater bodies at risk of algal bloom. By combining the organic chemistry and carbon isotopes of plant wax lipid biomarkers with a modeling framework, we estimate the relative biomass of submerged macrophytes in surface sediments of a shallow freshwater lake in the Yangtze floodplain, central China. Our estimates are in agreement with the results from satellite images, supporting the validity of the method. We found that water transparency, water depth, and nutrients in the lake correlate with the abundance of submerged macrophytes. Our results support the utility of the modeling framework in studies of lake ecology and climate of the past. The abundance of submerged macrophytes may also provide guidelines for the restoration and conservation of shallow freshwater lakes. Key Points: A Bayesian model incorporating concentrations and δ13C of n‐alkanes was used to quantify the contribution of submerged macrophytesThe model estimated distribution of submerged macrophytes agrees with the growing condition and PaqDiscrepancy between satellite imagery and model output suggest ground‐truthing is needed for future applications [ABSTRACT FROM AUTHOR]

Great Bear Lake (GBL) is the largest lake entirely within Canada and the largest polar‐type lake in the world. It holds cultural and sustenance value to the Délı˛ne Got'ine. However, its baseline physical limnology and how this may be altered by climate warming and anthropogenic stressors have received little attention. To explore the roles that surface heat exchange, wind, seasonal ice cover, and thermodynamic constraints play in the seasonal progression of ventilation and stratification of GBL, we report data from two 2008‐09 moorings, satellite‐derived lake surface temperatures, and observations made in 1964. Three spatially constrained processes regulate seasonal patterns of ventilation and stratification. Mid‐lake temperatures remain below the temperature of maximum density (TMDsurf = 3.98°C) throughout the year. In this area, solar radiation drives vertical convection while cooling develops stratification. Waters along the perimeter of the lake and within its five major arms do rise above TMDsurf in summer and stratify. It follows that mixing between the inner and outer domains form water at TMDsurf to create a convergent sinking zone or thermal bar. Because TMD decreases with increasing pressure, ventilation in the deepest region of the lake (McTavish Arm, Zmax = 446 m) requires wind‐aided downwelling to force cold surface water to a depth where it lies closer to the local TMD, triggering thermobaric instability, which then drives full‐depth ventilation. These patterns of ventilation and stratification constrain the availability of light and nutrients, therefore setting rates of biogeochemical processes, and regulating the lake's overall response to climate change. Plain Language Summary: Great Bear Lake (GBL), crossed by the Arctic Circle, is the world's largest polar‐type lake. It has three unique areas: the middle, where temperatures stay below 3.98°C, with dense water sinking in summer and stratification occurring in winter; the five protected arms, where temperatures exceed 3.98°C, creating stratification in both summer and winter, and interactions between the cooler main body and warmer arms form vertical barriers; and McTavish Arm, where depths reach 446 m show extra layering due to water compressibility, requiring wind convection for mixing. Our study examines these processes through comprehensive temperature data from 2008, 2009, and 1964, alongside satellite images, to understand the lake's ecology and response to climate change. Key Points: The mictic state of Great Bear Lake is a hybrid of three distinct thermodynamic processes affecting seasonal stratification and ventilationRadiatively driven convection, positive stratifications, and thermobaric stratification depend on the parts of the lakeThermobaric stratification constrains ventilation in the deeper reaches of the lake [ABSTRACT FROM AUTHOR]

Animals occupying higher trophic levels can have disproportionately large influence on ecosystem structure and functioning, owning to intricate behavioral responses to their environment, but the effects of behavioral adaptations on aquatic ecosystem dynamics are underrepresented, especially in model studies. Here, we explore how adaptive behavior of fish can affect the dynamics of aquatics ecosystems. We frame fish behavior in the context of the central trade‐off between feeding and predation, calculating the optimal level of feeding determined by ambient food availability and predation risk. To explore whole‐ecosystem consequences of fish behavior, we embed our behavioral model within the Water Ecosystems Tool (WET), a contemporary end‐to‐end aquatic ecosystem model. The principle of optimality provides a robust and mechanistic framework for representing animal behavior that is relevant for complex models, and can provide a stabilizing effect on model dynamics. The model predicts an emergent functional response similar to Holling type III, but with richer dynamics and a more rigorous theoretical foundation. We show how adaptive fish behavior works to stabilize food web dynamics compared to a control model with no optimal behavior, and how changing the strength of the underlying trade‐off has profound effects on trophic control and food web structure. Furthermore, we demonstrate how including fish behavior allows for an overall more realistic response of the model system to environmental perturbation in the form of nutrient enhancement. We discuss the structuring effects of behavioral adaptations in real ecosystems, and how approaches like this one may benefit aquatic ecological modeling. Our study further highlights how a mechanistic approach based on concepts from theoretical ecology can be successfully implemented in complex operational models resulting in improved dynamics and descriptive power. [ABSTRACT FROM AUTHOR]

With the acceleration of global warming and the intensification of anthropogenic activities, numerous lakes worldwide are experiencing reductions in their water surface areas. Yilong Lake, a typical shallow plateau lake located on the Yunnan–Guizhou Plateau in China, serves as a crucial water resource for local human production, daily life, and ecosystem services. Hence, long-term comprehensive monitoring of its dynamic changes is essential for its effective protection. However, previous studies have predominantly utilized remote sensing data with limited temporal resolution, thus failing to reflect the long-term variations in Yilong Lake's water body. This study employs high temporal resolution monitoring, utilizing multi-source satellite data (e.g., KeyHole, Landsat, HJ-1 A/B) images spanning from 1965 to 2022 to investigate the changes in Yilong Lake's surface area, analyzing the influencing factors and ecological impacts of these changes. The results indicate that from 1965 to 2022, Yilong Lake's water surface area decreased by 8.33 km2, with a maximum surface area of 40.49 km2 on 7 January 1986, and a minimum surface area of 10.64 km2 on 20 April 2013. These changes are characterized by three significant phases: (1) a rapid shrinking phase (1965–1979); (2) a fluctuating shrinking period (1986–2016); and (3) an expanding recovery phase (2016–2022). Spatially, the most significant shrinkage was observed along the southern and southwestern shores of the lake. The driving factors varied across different periods: sunshine duration was the dominant influence during the rapid shrinking phase (1965–1979), accounting for 82% of the changes; population and cropland area were the main drive factors during the fluctuating shrinking period (1986–2016), accounting for 56% of the changes; and during the expanding recovery phase (2016–2022), the population accounted for 75% of the changes in the lake's surface area. Currently, the protection of Yilong Lake depends on water supplementation and strict regulation of outflow, resulting in the lake exhibiting characteristics similar to a reservoir. This long-term investigation provides baseline information for future lake monitoring. Our research findings can also guide decision-makers in urban water resource management and environmental protection, ensuring the scientific and rational use of watershed water resources, effectively curbing the shrinkage of Yilong Lake, and achieving long-term sustainable restoration of the lake's ecology. [ABSTRACT FROM AUTHOR]

Lakes on the Tibetan Plateau (TP) serve as both indicators of and safeguards against climate change, playing a crucial role in the aquatic ecosystems of the TP. While considerable attention has been devoted to studying the thermal and dynamic processes of TP lakes, research focusing on their ecological variations has been limited. In this study, we selected Namco, a representative lake on the TP, to investigate its water ecological processes using the AQUATOX lake ecological model. Long-term ecological variations spanning from 1980 to 2020 were analyzed based on lake observations. Our results revealed a consistent increase in water nutrients, particularly total nitrogen (WTN), and total phosphorus (WTP), over the study period. Additionally, the concentrations of chlorophyll-a (Chl-a) and water gross and net primary production (WGPP and WNPP) exhibited a significant upward trend. Despite the persistent state of poor nutrition in the lake, the ecological conditions improved. Multiple linear regression analysis indicated that the concentrations of WGPP, WNPP, and Chl-a were more sensitive to the local climate and hydrology compared to WTN and WTP. A continuously warming climate would heat up the lake water body, further enhancing primary production and improving water quality in the future. This study provides insights for lake limnological and ecological research and can be used to inform water management strategies in high-altitude alpine regions. [ABSTRACT FROM AUTHOR]

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Conclusion: Lake reclamation cut off the direct seepage from the lake to groundwater in reclaimed farmland, the aquifer showed a connection with lake water by horizontal groundwater flow. The chemical analysis demonstrated that after reclamation, groundwater hydrodynamic conditions are gradually weakening. The lake-groundwater interaction interface is gradually varied and moves into the lake during this period. This change is easily ignored because the modification may take years to be observed. However, the lake ecology may be threatened seriously during this process. Lake reclamation project exerts anthropogenic pressures on the groundwater environment and lake ecosystem function, would affect the natural resilience of the lake systems and increases their vulnerability. [ABSTRACT FROM AUTHOR]

Accurate determination of reaeration coefficient in lakes is a key factor for accurate modeling of dissolved oxygen. This study developed a new numerical model to determine the lake reaeration coefficient of Sawa lake, Iraq based on solving the transform mechanisms of dissolved oxygen without the using the empirical and laboratory methods. The model solved the gas transport at the water-air surface numerically to predict the dissolved oxygen and the reaeration coefficient simultaneously. Results showed that the lake reaeration coefficient was 0.001 day-1 at 20 °C with low root mean squared errors (0.138, 0.137, and 0.168 mg/L for the three years of simulation 2007, 2012, and 2017, respectively) and absolute mean errors (0.121, 0.114, and 0.145 mg/L in 2007, 2012, and 2017, respectively). It was noticed that the lake habitat was impacted causing unhealthy conditions (low reaeration rate), and there was upward dissolved oxygen movement due to the presence of positive trend in the yearly cycle of temperature. In addition, including this numerical approach along with other water quality models can improve the predictions of other water quality parameters. [ABSTRACT FROM AUTHOR]

Abstract Animals occupying higher trophic levels can have disproportionately large influence on ecosystem structure and functioning, owning to intricate behavioral responses to their environment, but the effects of behavioral adaptations on aquatic ecosystem dynamics are underrepresented, especially in model studies. Here, we explore how adaptive behavior of fish can affect the dynamics of aquatics ecosystems. We frame fish behavior in the context of the central trade‐off between feeding and predation, calculating the optimal level of feeding determined by ambient food availability and predation risk. To explore whole‐ecosystem consequences of fish behavior, we embed our behavioral model within the Water Ecosystems Tool (WET), a contemporary end‐to‐end aquatic ecosystem model. The principle of optimality provides a robust and mechanistic framework for representing animal behavior that is relevant for complex models, and can provide a stabilizing effect on model dynamics. The model predicts an emergent functional response similar to Holling type III, but with richer dynamics and a more rigorous theoretical foundation. We show how adaptive fish behavior works to stabilize food web dynamics compared to a control model with no optimal behavior, and how changing the strength of the underlying trade‐off has profound effects on trophic control and food web structure. Furthermore, we demonstrate how including fish behavior allows for an overall more realistic response of the model system to environmental perturbation in the form of nutrient enhancement. We discuss the structuring effects of behavioral adaptations in real ecosystems, and how approaches like this one may benefit aquatic ecological modeling. Our study further highlights how a mechanistic approach based on concepts from theoretical ecology can be successfully implemented in complex operational models resulting in improved dynamics and descriptive power.

Lakes experience shifts in the timing of physical and biogeochemical events as a result of climate warming, and relative changes in the timing of events may have important ecological consequences. Spring, in particular, is a period in which many key processes that regulate the ecology and biogeochemistry of lakes occur and also a time that may experience significant changes under the influence of global warming. In this study, we used a coupled catchment–lake model forced by future climate projections to evaluate changes in the timing of spring discharge, ice-off, the spring phytoplankton peak, and the onset of stratification in a temperate mesotrophic lake. Although the model explained only part of the variation in these events, the overall patterns were simulated with little bias. All four events showed a clear trend towards earlier occurrence under climate warming, with ice cover tending to disappear at the end of the century in the most extreme climate scenario. Moreover, relative shifts in the timing of these springtime events also occurred, with the onset of stratification tending to advance more slowly than the other events and the spring phytoplankton peak and ice-off advancing faster in the most extreme climate scenario. The outcomes of this study stress the impact of climate change on the phenology of events in lakes and especially the relative shifts in timing during spring. This can have profound effects on food web dynamics as well as other regulatory processes and influence the lake for the remainder of the growing season. [ABSTRACT FROM AUTHOR]

Wetland vegetation and ecology of Lake Abaya in the southern Ethiopia was studied to determine floristic composition, plant community type and vegetation ecology. A total of 102 plots were laid along transects that were set up preferentially across areas where there were rapid changes in vegetation or marked environmental gradients to collect data on estimate of percentage aerial cover of plant species and environmental variables. Vegetation data was analyzed by agglomerative hierarchical cluster analysis using similarity ratio as a resemblance index and Ward's linkage method. Multivariate data analysis was performed using appropriate packages in R version 2.14.0. Canonical Correspondence Analysis (CCA) was used to explore the relationship between the species composition and environmental variables. The environmental data included in the CCA were determined using stepwise backward and forward selection of variables by ANOVA test. Statistical measurement regarding species diversity, richness and evenness of the plant community types was carried out by using Shannon-Wiener diversity indices. A total of 92 plant species belonging to 66 genera and 34 families were identified. Families Poaceae, Asteraceae, Fabaceae, Cyperaceae, Solanaceae, Euphorbiaceae and Amaranthaceae account for about 56.99% of the total proportion. Based on the cluster analysis, five plant community types were identified. The most important factors influencing the plant species composition and pattern of wetland plant communities were water drainage, water depth, land use, slope, altitude, and hydrogeomorphology. Therefore, these factors should be considered in future management and protection under the circumstance of climate change and human activities. [ABSTRACT FROM AUTHOR]

The wetlands are the partially water-submerged environments that are highly productive, and support fauna and flora species in significant numbers that are dependent for their survival on the organic production of wetlands. Kanwar Lake is situated about 22 kilometers to the northwest of Begusarai. The Gandak River, a tributary of the Ganges, meanders across the area, creating the largest oxbow lake in Asia. It is a natural body of water that is significant on many different levels, including ecological, floral, faunal, geomorphological, and zoological. In 1989, the state government of Bihar designated Kanwar as a protected area for avian species. It has been considered a Ramsar site since 1987, but the wetland was not one of the 13 designated sites. In 1984, the lake's area was 6,786 hectares (ha), but by 2004, it had shrunk to 6,043.825 ha. Only 2,032 hectares remained of the original lake area by 2012. Wealthy farmers and locals have rapidly colonized the lake bed. Lake biodiversity has declined as weeds have grown across the wetland. Widespread deforestation, overgrazing, unsustainable agricultural methods and over-exploitation of biomass for wood, fodder, and timber have stripped the land of its natural vegetative cover and exacerbated erosion. The research deals with the ecological study of the area and how urbanization has caused impacts on it. It focuses on how this has caused the deterioration of the lake and the measures for restoring the lake ecology, safeguarding the trend of urbanization. After analyzing the major key issues and analyzing the issues at the edge of the lake and around the Manjhaul, some of the major findings conclude that there is a need for stormwater management of the whole city, restoration of Kanwar wetland, and industrial control around the lake. [ABSTRACT FROM AUTHOR]

Acidic salt lakes are environments that harbor an array of biologically challenging conditions. Through 16S rRNA, 18S rRNA, and ITS amplicon sequencing of eight such lakes across the Yilgarn Craton of Western Australia, we aim to understand the microbial ecology of these lakes with a focus on iron- and sulfur-oxidizing and reducing microorganisms that have theoretical application in biomining industries. In spite of the biological challenges to life in these lakes, the microbial communities were highly diverse. Redundancy analysis of soil samples revealed sulfur, ammonium, organic carbon, and potassium were significant diversities of the microbial community composition. The most abundant microbes with a hypothetical application in biomining include the genus 9  M32 of the Acidithiobacillus family, Alicyclobacillus and Acidiphilium, all of which are possible iron- and/or sulfur-oxidizing bacteria. It is evident through this study that these lakes harbor multiple organisms with potential in biomining industries that should be exploited and studied further. [ABSTRACT FROM AUTHOR]

This document is a preface to a special issue series in the journal Aquatic Ecosystem Health & Management, focusing on the ecology and dynamics of Lake Erie. The authors, Mohiuddin Munawar and Stuart A. Ludsin, have a long history of studying Lake Erie and its ecosystem. They discuss the history of monitoring and research efforts on Lake Erie, including the development of the Great Lakes Water Quality Agreement and the establishment of monitoring programs. The preface also mentions the recent Cooperative Science and Monitoring Initiative (CSMI) focused on Lake Erie, which aimed to understand the impacts of eutrophication and harmful algal blooms on the lake's food web. The authors express their gratitude to the contributors and editors involved in the special issue series and hope that it will contribute to a better understanding of Lake Erie's ecology. [Extracted from the article]

Lake Çıldır, situated in eastern Turkey, is one of the most noteworthy freshwater lakes in the region, distinguished for its aesthetic allure and its paramount ecological and socio-economic roles. This review thoroughly examines Lake Çıldır, beginning with an introduction that contextualizes its importance. The climatic conditions influencing the lake's dynamics, its hydrographic characteristics, and the physicochemical variables determining its water quality have been specified. Our review synthesizes findings about the lake's biological attributes, including its varied flora and fauna. Detailed sections are dedicated to the fish species, macrophytes, benthic macroinvertebrates, and phytoplankton that inhabit the lake. Using land cover data, temporal changes in the lake's environmental structure have been evaluated. The lake's trophic state and overall ecological health are critically discussed, shedding light on its current status. Furthermore, the potential and existing ecotourism practices around Lake Çıldır are explored, emphasizing its value as a tourist destination. In conclusion, the challenges faced by the lake are addressed, advocating for robust conservation and management initiatives. This comprehensive review of Lake Çıldır's complex ecosystem is a foundation for forthcoming research. [ABSTRACT FROM AUTHOR]

Water levels in freshwater resources have been descending daily as global temperatures have risen and a coastal recession has occurred. The losses in these water basins have a significant influence on natural life. While drought is a global environmental issue, its consequences may be seen in Turkey. This study looks at the loss of water areas in Burdur Lake, one of Turkey's major lakes, between 2010 and 2021. The areas were identified using supervised classification, and the classification process was carried out for 2010, 2013, 2016, 2019, and 2021, respectively. Furthermore, several drought detection metrics, such as land surface temperature, soil moisture values, Normalized Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Palmer Drought Severity Index (PDSI), and precipitation amounts, have been evaluated for the study area between 2010 and 2021. The values of all drought detection indicators were also evaluated monthly for each year of the study. The analysis reveals abnormalities in all parameters, particularly in recent years, when compared to earlier years. Water areas decreased by 36.48% as a result of the classifications, whereas sandy areas increased by 89.85%. Again, the average values of various parameters used for drought detection over the years were compared. As a result, the indicator parameters gave reliable results as well as a means of monitoring the drought. [ABSTRACT FROM AUTHOR]

Background: Temperate subalpine lakes recovering from eutrophication in central Europe are experiencing harmful blooms due to the proliferation of Planktothrix rubescens, a potentially toxic cyanobacteria. To optimize the management of cyanobacteria blooms there is the need to better comprehend the combination of factors influencing the diversity and dominance of cyanobacteria and their impact on the lake's ecology. The goal of this study was to characterize the diversity and seasonal dynamics of cyanobacteria communities found in a water column of Lake Geneva, as well as the associated changes on bacterioplankton abundance and composition. Methods: We used 16S rRNA amplicon high throughput sequencing on more than 200 water samples collected from surface to 100 meters deep monthly over 18 months. Bacterioplankton abundance was determined by quantitative PCR and PICRUSt predictions were used to explore the functional pathways present in the community and to calculate functional diversity indices. Results: The obtained results confirmed that the most dominant cyanobacteria in Lake Geneva during autumn and winter was Planktothrix (corresponding to P. rubescens). Our data also showed an unexpectedly high relative abundance of picocyanobacterial genus Cyanobium, particularly during summertime. Multidimensional scaling of Bray Curtis dissimilarity revealed that the dominance of P. rubescens was coincident with a shift in the bacterioplankton community composition and a significant decline in bacterioplankton abundance, as well as a temporary reduction in the taxonomic and PICRUSt2 predicted functional diversity. Conclusion: Overall, this study expands our fundamental understanding of the seasonal dynamics of cyanobacteria communities along a vertical column in Lake Geneva and the ecology of P. rubescens, ultimately contributing to improve our preparedness against the potential occurrence of toxic blooms in the largest lake of western Europe. [ABSTRACT FROM AUTHOR]

This article discusses the intersections of art-making and research enquiry, focusing on methods, materiality and intentionality. In response to the request to contribute to an archive of creative methodological processes, the author examines a methodology he is developing for co-creating artistic acoustic ecologies with the Great Lakes. It raises questions about the role of practice-based research in generating new forms of enquiry and systems of knowledge while examining the barriers to achieving legitimacy for artistic practices within the research landscape. The article explores ethical, technological and artistic considerations within the context of the author's auto-ethnographic lens of an artist working in an era that demands verbalization as a primary articulation of knowledge and cultural expression. The author, a practising visual artist, musician and Ph.D. student in the research-creation-based Media and Design Innovation programme at Toronto Metropolitan University, discusses the need for concrete examples of how artistic research methods are effective. [ABSTRACT FROM AUTHOR]

The microbial ecology of meromictic lakes assessed with "omics" is still poorly studied compared to other aquatic systems. Here, a combination of metagenomics, high resolution sampling and detailed physical–chemical data gathering allowed to study the planktonic prokaryotic assemblages and metabolic capabilities in the crenogenic meromictic Lake El Tobar (Spain), a model lake for such purposes. This system presents a specific stratification comprising a freshwater layer and a halocline linked to the oxycline, driving to the euxinic hypersaline waters of the deep monimolimnion. The different strata showed a highly diverse and vertically distributed microbiome with their metabolic capacities fitting/influencing the physical–chemical environment. Overall, up to 338 novel genomes were found from metagenome assembled genomes. Picocyanobacteria and methanotrophs were abundant in the upper part of the oxycline. Anoxygenic phototrophs (Chlorobium, Thiohalocapsa, Chromatiaceae, Rhodospirillum, and Rhodobacteraceae spp.) dominated the 12.5–14 m anoxic waters with dim light availability. Sulfate reducers (Desulfobacterota and Firmicutes) inhabited low redox horizons from 13.5 to the bottom (18 m). The potential microbial synergistic performance increases toward the monimolimnion. Among these, a microbial assemblage mostly composed of Spirochaetota, Cloacimonadota, Omitrophota, Firmicutes, Marinisomatota, Nanoarchaeota, and Patescibacteria in hypersaline waters of 14–18 m (conductivities of 118–213 mS cm−1), is potentially capable of performing mixed‐acid fermentations, even including hydrogen and butanol biosynthesis of biotechnological interest. This metagenomics study shows how microbial lifestyles may be determinant in the interplay of environmental gradients, and exemplifies the potential interactions between the microbial guilds thereby. [ABSTRACT FROM AUTHOR]

Abstract Many Norwegian rivers and lakes are regulated for hydropower, which affects freshwater ecosystems and anadromous fish species, such as sea trout (Salmo trutta). Lakes are an important feature of many anadromous river systems. However, there is limited knowledge on the importance of lakes as habitat for sea trout and how hydropower affects the behaviour of sea trout in lakes. To investigate this, we conducted an acoustic telemetry study. A total of 31 adult sea trout (532 ± 93 mm total length) were captured by angling in river Aurlandselva, Norway, and tagged between July 20 and August 12, 2021. The tags were instrumented with accelerometer, temperature, and depth sensors, which provided information on the sea trout’s presence and behaviour in lake Vassbygdevatnet. Our results indicate that there was a large prevalence of sea trout in the lake during the spawning migration, and that the sea trout were less active in the lake compared to the riverine habitats. An increase in activity of sea trout in the lake during autumn might indicate that sea trout spawn in the lake. However, the discharge from the high-head storage plant into the lake did not affect the depth use or activity of sea trout in the lake. Furthermore, the large prevalence of spawners in the lake during autumn will likely cause an underestimation of the size of the sea trout population in rivers with lakes during annual stock assessment. In conclusion, our results could not find evidence of a large impact of the discharge on the behaviour of sea trout in the lake.

Lakes on the Tibetan Plateau (TP) serve as both indicators of and safeguards against climate change, playing a crucial role in the aquatic ecosystems of the TP. While considerable attention has been devoted to studying the thermal and dynamic processes of TP lakes, research focusing on their ecological variations has been limited. In this study, we selected Namco, a representative lake on the TP, to investigate its water ecological processes using the AQUATOX lake ecological model. Long-term ecological variations spanning from 1980 to 2020 were analyzed based on lake observations. Our results revealed a consistent increase in water nutrients, particularly total nitrogen (WTN), and total phosphorus (WTP), over the study period. Additionally, the concentrations of chlorophyll-a (Chl-a) and water gross and net primary production (WGPP and WNPP) exhibited a significant upward trend. Despite the persistent state of poor nutrition in the lake, the ecological conditions improved. Multiple linear regression analysis indicated that the concentrations of WGPP, WNPP, and Chl-a were more sensitive to the local climate and hydrology compared to WTN and WTP. A continuously warming climate would heat up the lake water body, further enhancing primary production and improving water quality in the future. This study provides insights for lake limnological and ecological research and can be used to inform water management strategies in high-altitude alpine regions.

Many Norwegian rivers and lakes are regulated for hydropower, which affects freshwater ecosystems and anadromous fish species, such as sea trout (Salmo trutta). Lakes are an important feature of many anadromous river systems. However, there is limited knowledge on the importance of lakes as habitat for sea trout and how hydropower affects the behaviour of sea trout in lakes. To investigate this, we conducted an acoustic telemetry study. A total of 31 adult sea trout (532 ± 93 mm total length) were captured by angling in river Aurlandselva, Norway, and tagged between July 20 and August 12, 2021. The tags were instrumented with accelerometer, temperature, and depth sensors, which provided information on the sea trout's presence and behaviour in lake Vassbygdevatnet. Our results indicate that there was a large prevalence of sea trout in the lake during the spawning migration, and that the sea trout were less active in the lake compared to the riverine habitats. An increase in activity of sea trout in the lake during autumn might indicate that sea trout spawn in the lake. However, the discharge from the high-head storage plant into the lake did not affect the depth use or activity of sea trout in the lake. Furthermore, the large prevalence of spawners in the lake during autumn will likely cause an underestimation of the size of the sea trout population in rivers with lakes during annual stock assessment. In conclusion, our results could not find evidence of a large impact of the discharge on the behaviour of sea trout in the lake. [ABSTRACT FROM AUTHOR]

This article provides an overview of the changes in the Lake Erie ecosystem caused by human-induced environmental stress. It emphasizes the importance of understanding these changes to develop effective management strategies. The article specifically focuses on the dynamics of nutrients, microbes, algae, and dreissenid mussels in Lake Erie. It discusses the factors driving changes in nutrient loading, algal and cyanobacterial dynamics, and dreissenid growth. The article presents research findings on these topics and their implications for management decision-making. The studies conducted on dreissenid mussels in Lake Erie suggest that their impact may be less significant than previously believed, but their localized distribution could still have a high impact. The studies also highlight the need for frequent benthic surveys to better understand and predict the effects of dreissenids. [Extracted from the article]

Lakes experience shifts in the timing of processes as a result of climate warming, and especially relative changes in the timing of events may have important ecological consequences. Spring in particular is a period in which many key processes that regulate the ecology and biogeochemistry of lakes occur, and also a time which may experience significant changes under influence of global warming. In this study, we used a coupled catchment-lake model forced by future climate projections to evaluate changes in the timing of spring discharge, ice-off, the spring phytoplankton peak, and the onset of stratification, in a mesotrophic, temperate lake. All these events showed a clear trend towards earlier occurrence with climate warming, with ice cover tending to disappear at the end of the century in the most extreme climate scenario. Moreover, relative shifts in the timing of these springtime events also occurred, with the onset of stratification tending to advance slower than the other events, and the spring phytoplankton peak and ice-off advancing faster in the most extreme climate scenario. The outcomes of this study stress the impact of climate change on the phenology of processes in lakes and especially the relative shifts in timing during spring. This can have profound effects on food-web dynamics as well as other regulatory processes, and influence the lake for the remainder of the growing season. [ABSTRACT FROM AUTHOR]

The practice of seine fishing for vendace (Coregonus albula) has continued as an unbroken tradition in Lake Puruvesi in eastern Finland since 1300 AD. While fishing methods have evolved, the fishery still relies heavily on the traditional knowledge of practitioners, which is passed along from generation to generation. Traditional knowledge of weather patterns, the fish themselves, and other components of the lake ecosystem have allowed fishers to maintain an economically viable fishery without depleting fish stocks. Lake Puruvesi and its traditional seine fishery represent a stronghold of Finnish fishing culture and traditional ecological knowledge. In recent years, local observations by fishers have identified threats to the lake ecosystem and the fishery, including eutrophication, climate change-related threats to fish, and climate-related disruption of fishing practices. This paper explores the unique ecological, social, and economic characteristics that have allowed the fishery to remain sustainable. We discuss the role of traditional knowledge in maintaining the fishery and we use a socio-ecological framework to broadly assess the value of the fishery. We also consider threats facing the fish and fishery and discuss approaches taken by fishers to address those threats. [ABSTRACT FROM AUTHOR]

Gin-buna crucian carp Carassius sp. is a widely distributed cyprinid fish inhabiting lakes and rivers throughout Japan. The species is categorized on the Red List of Shiga Prefecture as a "Species of Concern", given a suspected population decline in Lake Biwa; however, its spawning ecology in the lake is yet to be fully elucidated. Therefore, in this study, we examined the spawning and migratory behavior of gin-buna crucian carp at a lakeside biotope connected to the lake via egg survey and acoustic telemetry. DNA analyses of field-collected eggs showed that gin-buna spawned in the biotope during March–April in 2019 and 2020. Three gin-buna captured in the biotope were tagged with acoustic transmitters and released into the lake in October 2019, and one individual returned to the biotope in March 2020. These results suggest that some individuals of gin-buna use the biotope as a spawning ground for multiple years. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Burullus Lake, which is the second-largest coastal lagoon in Egypt, is deteriorating due to nutrient enrichment and pollutant loading. The study aims to assess the lake's water quality using water quality indices and microbiological assessment. Surface water samples were collected from Burullus Lake in winter and summer, as well as samples from drains that discharge waste into the lake. Most lake stations are classified in the marginal category based on the water quality index (WQI). Dissolved oxygen, ammonia, copper, and cadmium have the greatest impact on WQI, reflecting pollution loads. Based on the contamination index, heavy metal classification results ranged from "lowly polluted" to "highly polluted." According to the Nemerow Index, human activity has significantly impaired the ecology of the lake and surrounding drains through copper and cadmium pollution. The fecal coliform/fecal streptococci ratio was less than 0.6 in lake water samples, suggesting fecal contamination from domesticated animal wastes. Drain water contaminated with fecal streptococci indicated frequent contamination. Several drains allow a significant amount of effluent, including high amounts of pesticides and fertilizers, to enter the lake, causing serious metal and microbiological pollution Dredging and deepening the inlet link between the lake and Mediterranean Sea have had a positive impact on water quality. However, there are still other options for improving the lake's health. Therefore, it is recommended to routinely check Burullus Lake's water quality and its surrounding drains to keep track of its condition and assess any improvement efforts' effectiveness. [ABSTRACT FROM AUTHOR]

Most oxbow-lakes, spreading out in the riparian of Kampar river, were ecologically unsustainable due to social and anthropological reasons including intensive agriculture in the upper land, extensive urban around the lakes. Published papers suggested that the oxbow lakes ecosystem were degraded, biodiversity of the aquatic fauna were in adversity. Those threats have social economical affect on the local community. The present paper analyzes the sustainability of Teluk Benderas Lake, an riparian oxbow lake of Kampar, Pangkalan Kerinci District, Riau. The sustainability were analyzed from the perspective of ecological, economical, sociocultural, legal-institutional and technological. Sustainability analysis was carried out using the MDS (Multidimensional Scaling) analysis approach with the help of RapOxbow software (modified Rapfish). It revealed that based on ecological, economical, technological dimensions, the lake standing were unsustainable, with sustainability index of 29.8%, 30.0%, 44.3%, respectively. Meanwhile, the sustainability index of socio-cultural and legal-institutional, appeared 65.6%, 51.3%, respectively (fairly sustainable). It is suggested that 11 the driving variables that have been identified, should be evaluated and managed holistically in order to improve and enhance the sustainability of Lake ecosystem. In short, the role of local government were of important on this matter. Accordingly, the strategy and management plan and action plan for the Teluk Benderas Lake ecosystem need to be implemented integratedly by developing (a) sustainable small scale fisheries business (b). developing of alternative income generations (c) strengthening the role of traditional leaders and institutions. [ABSTRACT FROM AUTHOR]

Lake ice melting and breakup form a fast, nonlinear process with important mechanical, chemical, and biological consequences. The process is difficult to study in the field due to safety issues, and therefore only little is known about its details. In the present work, the field data were collected on foot, by hydrocopter, and by boat for a full time series of the evolution of ice thickness, structure, and geochemistry through the melting period. The observations were made in lake Pääjärvi in 2018 (pilot study) and 2022. In 2022, the maximum thickness of ice was 55 cm with 60 % snow ice, and in 40 d the ice melted by 33 cm from the surface and 22 cm from the bottom while the porosity increased from less than 5 % to 40 %–50 % at breakup. In 2018, the snow-ice layer was thin, and bottom and internal melting dominated the ice decay. The mean melting rates were 1.31 cm d -1 in 2022 and 1.55 cm d -1 in 2018. In 2022 the electrical conductivity (EC) of ice was 11.4 ± 5.79 µ S cm -1 , which is 1 order of magnitude lower than in the lake water, and ice pH was 6.44 ± 0.28, which is lower by 0.4 than in water. The pH and EC of ice and water decreased during the ice decay except for slight increases in ice due to flushing by lake water. Chlorophyll a was less than 0.5 µ g L -1 in porous ice, approximately one-third of that in the lake water. The results are important for understanding the process of ice decay with consequences for lake ecology, further development of numerical lake ice models, and modeling the safety of ice cover and ice loads. [ABSTRACT FROM AUTHOR]

Lake Texcoco in Mexico is a remarkable place for observing how human and natural relationships evolve through time in a landscape. Since the opening of the watershed and the draining of the lake, there have been various attempts to exploit the area, although few have succeeded. This study highlights the importance of historical analysis in identifying socio-natural processes that have historically influenced lake use, degradation, management, and conservation. The novelty of this study lies in its application of a historical political ecology approach to understand the evolving dynamics between power relations and the ecology of the former Lake Texcoco in Mexico Valley. By examining both the ecological and political-economic history of the lake, this study reveals how conflicts related to natural resource management in the past have influenced the ecological dynamics of the present. Overall, this study presents a unique perspective on the socio-natural history of Lake Texcoco, demonstrating the potential of using historical political ecology to understand the long-term effects of environmental change. [ABSTRACT FROM AUTHOR]

Meromictic Crawford Lake, located in SW Ontario, Canada is characterized by varved sediments, making it suitable for high-resolution paleoecological studies. Freeze cores, the only coring method available that reliably preserves the fragile laminations representative of seasonal deposition in the lake, were used to document siliceous diatom and chrysophyte community structure at an annual resolution from 1930– 1990CE. Stratigraphically constrained cluster analysis identified major assemblage changes that are believed to have been caused by local, regional and possibly global anthropogenic impacts. The assemblage changes within the siliceous algae are attributed to regional weather and increased industrial emissions and related effects of acid deposition on the lake’s catchment associated with the Great Acceleration –the massive economic, industrial, and demographic expansion beginning in the mid-20th century. Observed increases in spheroidal carbonaceous particles (SCPs) in varved lake sediment dating to the early 1950s record rapidly expanding steel production without emission controls around 30 km upwind of the lake. The findings reported here reflect major changes in earth systems that the Anthropocene Working Group recommends for a proposed epoch to be termed the Anthropocene, providing support for the laminated sediments from Crawford Lake as a potential Global boundary Stratotype Section and Point (GSSP). [ABSTRACT FROM AUTHOR]

Cyanobacterial expansion is harmful to the environment, the ecology of Lake Baikal and the economy of nearby regions and can be dangerous to people and animals. Since 2011, the process of colonisation of the lake with potentially toxic cyanobacteria belonging to the genus Tychonema has continued. An understanding of the mechanism of successful expansion of Tychonema requires scrutiny of biological and genomic features. Tychonema sp. BBK16 was isolated from the coastal zone of Lake Baikal. The morphology of BBK16 biofilm was studied with light, scanning electron and confocal microscopy. The biofilm is based on filaments of cyanobacteria, which are intertwined like felt; there are also dense fascicles of rope-like twisted filaments that impart heterogeneity to the surface of the biofilm. Genome sequencing, intergenomic comparisons and phylogenetic analyses indicated that Tychonema sp. BBK16 represent a new species related to planktic cyanobacterium Tychonema bourrellyi, isolated from Alpine lentic freshwater. Genome investigation revealed the genes possibly responsible for the mixotrophic lifestyle. The presence of CRISPR-Cas and restriction modification defence mechanisms allowed to suggest the existence of phages infecting Tychonema sp. BBK16. Analysis of CRISPR spacers and prophage-derived regions allowed to suggest related cyanophages. Genomic analysis supported the assumption that mobile elements and horizontal transfer participate in shaping the Tychonema sp. BBK16 genome. The findings of the current research suggest that the aptitude of Tychonema sp. BBK16 for biofilm formation and, possibly, its mixotrophic lifestyle provide adaptation advantages that lead to the successful expansion of this cyanobacterium in the Baikal's conditions of freshwater lake environments. [ABSTRACT FROM AUTHOR]

The geographical location of West Taihu Lake determines that it is the entrance of the whole Taihu Lake, and the intensive industries around it pose a great threat to the ecology of Taihu Lake. We innovatively combined Pb isotope ratio analysis with ecological risk assessment index to quantify the source-oriented ecological risk of heavy metals (HMs) in the sediments of West Taihu Lake. In this study, the representative HMs Zn, Pb, Cr, and Cd in the surface (0–2 cm) sediments of West Tai Lake were determined, and the ecological risk assessment of HM sources was carried out based on the Pb isotope ratio and ecological risk index. The results showed that HMs were significantly enriched in the south and the west of the study area. The average geo-accumulation index (Igeo) of Pb was unpolluted, Cr and Zn were between unpolluted and moderately polluted, and Cd was moderately polluted. The average ecological risk index (Ei) of Pb, Cr, and Zn was low, and only Cd reached a considerable risk (ECd = 120.7), which accounted for 89.8% of the comprehensive ecological risk index (RI). However, the RI in the whole study area (RI = 134.4) still indicated low risk. There was a significant correlation between Pb and other HMs (P < 0.05). The IsoSource analysis showed that the order of contribution rate was fossil fuels (48.0%) > industrial sources (35.8%) > natural sources (14.9%) > agricultural sources (1.3%). The HM pollution caused by fossil fuel combustion and industrial activities reaches a moderate ecological risk, whereas natural sources and agricultural sources pose a low risk. Overall, the main sources of HM pollution are anthropogenic, which pose moderate ecological risk to the study area and should be paid more attention to. [ABSTRACT FROM AUTHOR]

Sedimentary DNA-based studies revealed the effects of human activity on lake cyanobacteria communities over the last centuries, yet we continue to lack information over longer timescales. Here, we apply high-resolution molecular analyses on sedimentary ancient DNA to reconstruct the history of cyanobacteria throughout the Holocene in a lake in north-eastern Germany. We find a substantial increase in cyanobacteria abundance coinciding with deforestation during the early Bronze Age around 4000 years ago, suggesting increased nutrient supply to the lake by local communities settling on the lakeshore. The next substantial human-driven increase in cyanobacteria abundance occurred only about a century ago due to intensified agricultural fertilisation which caused the dominance of potentially toxic taxa (e.g., Aphanizomenon). Our study provides evidence that humans began to locally impact lake ecology much earlier than previously assumed. Consequently, managing aquatic systems today requires awareness of the legacy of human influence dating back potentially several millennia. Analysis of sedimentary DNA through time in a German lake shows a spike in cyanobacteria abundance coinciding with human activity in the Bronze Age. [ABSTRACT FROM AUTHOR]

Wular Lake, one of the largest wetlands in Asia (13,000 ha in Kashmir Valley) is a biodiversity‐rich Ramsar site supporting nearly 32,000 rural people involved in harvesting fish, water chestnuts, lotus stems and fodder. With 2914 active fishers, Wular Lake contributes 54% of Kashmir's total fish catch. Large‐scale land‐use changes and global warming have resulted in siltation, reduced lake area and alterations in the water flow regime, threatening lake ecology and human livelihoods. A novel census‐based multi‐criteria Socio‐Economic Vulnerability Index (SEVI) was used to assess the vulnerability status of 23 fishing and 115 non‐fishing adjacent villages. All the fishing villages exhibited 'low' (0.21–0.40) vulnerability levels, except Kunas village (0.42). Interestingly, no significant differences could be found in vulnerability levels between fishing (23) and non‐fishing (115) villages, although the former exhibited relatively higher social sensitivity. A graphical decision matrix based on sensitivity and adaptive capacity scores provided a snapshot of vulnerability status for each village. Using SEVI scores, drivers (i.e., key indicators responsible for high sensitivity & low adaptive capacity) were identified and corresponding village‐specific development interventions are suggested with Kunas as an illustrative case village. Improving education levels, strengthening community and rural infrastructure, and expanding livelihood options were key short‐term strategies for improving resilience in Kashmir's Wular region. [ABSTRACT FROM AUTHOR]

Paleolimnological assessment of Ladik Lake (N Turkey) using diatoms was carried out along a 62 cm-long sediment core recovered from the southeastern part of the lake. The chronology of the sediments was established by 137Cs - 210Pb dating. Accordingly, three major chronostratigraphical diatom assemblage zones (DAZ) were defined by the CONISS (constrained cluster analysis) program. The oldest assemblage, DAZ C (AD 1925-1958), was dominated by Ulnaria ulna (Nitzsch) Compère, Cocconeis placentula Ehrenb. and Cocconeis pediculus Ehrenb. taxon. In DAZ B (AD 1958-1986), in addition to Ulnaria ulna species that dominated through the whole core, Epithemia spp. occasionally dominated the assemblage in this zone. Ulnaria ulna and Pantocsekiella ocellata (Pant.) K.T. Kiss & Ács predominated since the beginning of DAZ A (AD 1986-2006). After the first regime of the lake with dystrophic character, the diatom community underwent a significant shift, with decreased abundance of periphytic diatom samples. The improvement of the regulator in 1986 resulted in a larger water level increase that affected the lake ecology, causing a shift from a diverse periphytic diatom to planktonic diatom assemblage. Based on our monitoring it can be inferred that the limnological regime shifts in Ladik Lake during the 20th century are of anthropogenic origin, rather than being due to climatic changes. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As one of the most important reservoirs of water in arid regions, lakes experience a series of complicated changes. However, the natural driving mechanisms behind such changes remain unclear. In this study, we collected data from 1333 lakes in the arid region of Central East Asia (CEA) to investigate the underlying natural causes of lake changes over the past five decades. The lakes were located within three different geomorphological zones: (I) Tibetan Plateau zone; (II) high mountain—basin zone; and (III) low mountain zone. Our results show that lakes as a whole in CEA exhibit a unique change trend, with an overall lake area increase of 7099 km2 (41%) and with heterogeneous spatial variations over the past five decades. The lake area increase was 6236 km2 (47%), 935 km2 (31%) and decrease was 72 km2 (~1%) in zones I, II, and III, respectively. The different geomorphological zones have influencing factors. In zones I and II, increased precipitation (including cloud water) and temperature rise (causing glacier, frozen soil, and snow melt) contributed to approximately 66% of the change in lake area; in zone III, changes in precipitation contributed to approximately 87% of the lake changes. Increased atmospheric circulation of water vapor caused by warming of the ocean surface appears to be the main driving factor of these changes; this is supported by future projection scenarios. From 2006 to 2098, temperature and precipitation will increase by 4.0–7.8 °C and 1.07 to 1.29 mm per day, respectively, under both the RCP4.5 and RCP8.5 scenarios. Notably, although the climate appears to have become more optimum for lakes in CEA at the interdecadal timescale, short timescale climatic events such as lake expansion will bring more extreme climate events, such as extreme high-temperature heat waves, which should be considered as a potential threat to lake ecology in the future. [ABSTRACT FROM AUTHOR]

At broad spatial scales, primary productivity in lakes is known to increase in concert with nutrients, and variables that may disrupt or modify the tight coupling of nutrients and algae are of increasing interest, particularly for those shifting with climate change. Storms may disrupt algae–nutrient relationships, but the expected effects differ between winter and summer seasons, particularly for seasonally ice‐covered lakes. In winter, storms can dramatically change the under‐ice light environment, creating light limitation that disrupts algae–nutrient relationships. Further, storms can bring both snow that blocks light and also wind that blows snow off of ice. In open water conditions, storms may promote turbulence and external nutrient loading. Here, we test the hypotheses that winter and summer storms differentially affect algae–nutrient relationships across 84 seasonally ice‐covered lakes included in the Ecology Under Lake Ice dataset. While nutrients explained most of the variation in chlorophyll across these lakes, we found that secondary drivers differed between seasons. Under‐ice chlorophyll was higher under a variety of precipitation and wind conditions that tend to promote snow‐free clear ice, highlighting the importance of light as a limiting factor for algal growth during winter. In summer, higher water temperatures and storms corresponded with higher chlorophyll. Our study suggests that examining ice‐covered lakes in a gradient from the perennial ice cover of the poles to the intermittent ice cover of lower latitudes would yield key information on the shifts in light and nutrient limitation that control algal biomass. [ABSTRACT FROM AUTHOR]

Antibiotics, as pollutants of emerging concern, can enter marine environments, rivers, and lakes and endanger ecology and human health. The purpose of this study was to review the studies conducted on the presence of antibiotics in water, sediments, and organisms in aquatic environments (i.e., seas, rivers, and lakes). Most of the reviewed studies were conducted in 2018 (15%) and 2014 (11%). Antibiotics were reported in aqueous media at a concentration of <1 ng/L–100 μg/L. The results showed that the highest number of works were conducted in the Asian continent (seas: 74%, rivers: 78%, lakes: 87%, living organisms: 100%). The highest concentration of antibiotics in water and sea sediments, with a frequency of 49%, was related to fluoroquinolones. According to the results, the highest amounts of antibiotics in water and sediment were reported as 460 ng/L and 406 ng/g, respectively. In rivers, sulfonamides had the highest abundance (30%). Fluoroquinolones (with an abundance of 34%) had the highest concentration in lakes. Moreover, the highest concentration of fluoroquinolones in living organisms was reported at 68,000 ng/g, with a frequency of 39%. According to the obtained results, it can be concluded that sulfonamides and fluoroquinolones are among the most dangerous antibiotics due to their high concentrations in the environment. This review provides timely information regarding the presence of antibiotics in different aquatic environments, which can be helpful for estimating ecological risks, contamination levels, and their management. [ABSTRACT FROM AUTHOR]

Global land-use changes have a significant impact on the environment and food security, and escalating human activity and uncontrolled agricultural land expansion pose a grave threat to regional ecosystems. This study aims to assess the challenges faced by the environment and food security, with a particular focus on the impact of land use change on ecosystems. The study selected the Ebinur Lake Basin, a typical arid region in China, as the object and analyzed the land type changes from 2013 to 2021 using the Google Earth Engine platform and the China Land Cover Dataset. We created an Improved Water-Benefit-Based Ecological Index (IWBEI) based on the poor air quality environment in the watershed, and then calculated the ecological index of the watershed. The results indicate that the grassland and bare land areas in the Ebinur Lake Basin have fluctuated and shown an overall downward trend. The trend of farmland expansion is to expand to surrounding areas on the basis of existing farmland. The overall center of gravity of cultivated land in the watershed is moving from northwest to southeast, mainly towards the water source area. The IWBEI index is more prominent in identifying cultivated land and wetlands in arid regions. According to IWBEI's calculations, the priority order of land types is: forest > cultivated land > wetland > water > snow > grassland > impermeable surface > bare land. The overall ecological environment quality of the watershed is showing a deteriorating trend. Therefore, relevant departments should pay attention to the impact of farmland expansion on the local ecological environment to avoid the continuous deterioration of the ecological environment. • The center of gravity of farmland in the watershed shifts northwest to southeast, mainly towards water sources. • The IWBEI index aims to improve regional air quality. • The IWBEI index outperforms the WBEI index in identifying farmland and wetlands. • Overall, the watershed's ecological environment is deteriorating. [ABSTRACT FROM AUTHOR]

Lake Victoria is the second largest freshwater lake in the world that was once a biodiversity hotspot hosting over 500 endemic haplochromine cichlids that were later decimated by exotic introductions and anthropogenically driven environmental and ecological changes. The environmental and ecological changes in the lake over the years have been attributed to overfishing, eutrophication, introduction of exotic species, pollution and possibly climate change. The lake's capture fishery, which is the main economic activity directly and indirectly supporting over 40 million people, has continued to decline after experiencing a boom between the 1970s and 1990s following the introduction of Nile Perch (Lates niloticus) and Nile Tilapia (Oreochromis niloticus). In order to augment capture fisheries from the lake, cage culture was introduced in 2005, but its sustainability and influence on the ecology of the lake are not well understood. In this review, we examine the genesis of degradation of Lake Victoria and assess the role of cage culture as both a solution to the current situation and a cause for concern for the ecology of the lake. To compile this review, we utilized data in the grey and published literature. Studies show that the degradation of the lake can be traced back to the 1930s when the trophic status and ecology of the lake started showing signs of anthropogenic influence. The Nile Perch was introduced in early 1960s to replenish the fishery but its ecological impacts were felt in 1970s and 1980s when the native haplochromine species started to disappear from catches. Progressively, the ecological changes and management concerns in the lake have become a complex mix of exotic species introductions, eutrophication, and overfishing. In this mix of persistent ecological changes, the once thriving capture fisheries revolving around the two exotic species (L. niloticus and O. niloticus) have significantly declined threatening the livelihoods of millions of people directly and indirectly involved in the fisheries. These declines necessitated the introduction of cage culture in 2005 to fill the increasing demand for fish from the lake. Ever since, cage numbers have increased tremendously (>6 000 by 2020) and is now operated by over 60 different firms which are owned either individually or by groups. Over 70% of the cages have been installed in shallow areas within the Winam Gulf which goes against the guidelines on cage installation and operation; regulations on cage farming were introduced after the activity had gained momentum in the lake. Limnological data in areas of the lake that have been stocked with cages has shown evidence of negative effects on water quality. This decline in water quality can be attributed to remnant feeds used in cages, of which 50% are the sinking types, and wastes from fish excretion and egestion. Although data are limited, the potential influence of cage farming on the already altered ecology and environment of Lake Victoria needs to be recognized and investigated. This study recommends studies targeting operations of cages in the lake, including a comprehensive environmental audit to inform their sustainability and relevant policy. [ABSTRACT FROM AUTHOR]