Limnological Review

15 pages, 3267 KiB

Open AccessArticle

Monitoring and Analyzing Aquatic Vegetation Using Sentinel-2 Imagery Time Series: A Case Study in Chimaditida Shallow Lake in Greece

by Maria Kofidou and Vasilios Ampas

Limnol. Rev. 2025, 25(3), 35; https://doi.org/10.3390/limnolrev25030035 (registering DOI) - 1 Aug 2025

Abstract

Aquatic vegetation plays a crucial role in freshwater ecosystems by providing habitats, regulating water quality, and supporting biodiversity. This study aims to monitor and analyze the dynamics of aquatic vegetation in Chimaditida Shallow Lake, Greece, using Sentinel-2 satellite imagery, with validation from field [...] Read more.

Aquatic vegetation plays a crucial role in freshwater ecosystems by providing habitats, regulating water quality, and supporting biodiversity. This study aims to monitor and analyze the dynamics of aquatic vegetation in Chimaditida Shallow Lake, Greece, using Sentinel-2 satellite imagery, with validation from field measurements. Data processing was performed using Google Earth Engine and QGIS. The study focuses on discriminating and mapping two classes of aquatic surface conditions: areas covered with Floating and Emergent Aquatic Vegetation and open water, covering all seasons from 1 March 2024, to 28 February 2025. Spectral bands such as B04 (red), B08 (near infrared), B03 (green), and B11 (shortwave infrared) were used, along with indices like the Modified Normalized Difference Water Index and Normalized Difference Vegetation Index. The classification was enhanced using Otsu’s thresholding technique to distinguish accurately between Floating and Emergent Aquatic Vegetation and open water. Seasonal fluctuations were observed, with significant peaks in vegetation growth during the summer and autumn months, including a peak coverage of 2.08 km² on 9 September 2024 and a low of 0.00068 km² on 28 December 2024. These variations correspond to the seasonal growth patterns of Floating and Emergent Aquatic Vegetation, driven by temperature and nutrient availability. The study achieved a high overall classification accuracy of 89.31%, with producer accuracy for Floating and Emergent Aquatic Vegetation at 97.42% and user accuracy at 95.38%. Validation with Unmanned Aerial Vehicle-based aerial surveys showed a strong correlation (R² = 0.88) between satellite-derived and field data, underscoring the reliability of Sentinel-2 for aquatic vegetation monitoring. Findings highlight the potential of satellite-based remote sensing to monitor vegetation health and dynamics, offering valuable insights for the management and conservation of freshwater ecosystems. The results are particularly useful for governmental authorities and natural park administrations, enabling near-real-time monitoring to mitigate the impacts of overgrowth on water quality, biodiversity, and ecosystem services. This methodology provides a cost-effective alternative for long-term environmental monitoring, especially in regions where traditional methods are impractical or costly. Full article

► Show Figures

Figure 1

13 pages, 1482 KiB

Open AccessArticle

Effect of Surrounding Detritus on Phragmites australis Litter Decomposition: Evidence from Laboratory Aquatic Microcosms

by Franca Sangiorgio, Daniela Santagata, Fabio Vignes, Maurizio Pinna and Alberto Basset

Limnol. Rev. 2025, 25(3), 34; https://doi.org/10.3390/limnolrev25030034 (registering DOI) - 1 Aug 2025

Abstract

The availability of detritus is a key factor influencing aquatic biota and can significantly affect decomposition processes. In this study, we investigated how varying quantities of surrounding detritus impact leaf litter decay rates. It was tested in flowing and still-water microcosms to highlight [...] Read more.

The availability of detritus is a key factor influencing aquatic biota and can significantly affect decomposition processes. In this study, we investigated how varying quantities of surrounding detritus impact leaf litter decay rates. It was tested in flowing and still-water microcosms to highlight context-dependent effects of surrounding detritus on leaf litter decomposition. To isolate the effect of detritus amount, experiments were conducted in laboratory microcosms simulating lotic and lentic ecosystems, each containing leaf fragments for decomposition assessments. Four detritus quantities were tested, with invertebrates either allowed or restricted from moving among detritus patches. Leaf decomposition rates were influenced by the amount of surrounding detritus, with slower decay observed at higher detritus conditions, regardless of invertebrate mobility. Detritivore distribution responded to both detritus quantity and oxygen availability, showing a preference for high detritus conditions. Additionally, detritus quantity affected microbial activity with a quadratic response, as indicated by leaf respiration rates. Overall, our findings indicate that the amount of surrounding detritus modulates leaf litter decomposition independently of invertebrate density, by influencing oxygen dynamics and, consequently, the activity of biological decomposers. Full article

► Show Figures

Graphical abstract

22 pages, 5044 KiB

Open AccessReview

Paleolimnological Approaches to Track Anthropogenic Eutrophication in Lacustrine Systems Across the American Continent: A Review

by Cinthya Soledad Manjarrez-Rangel, Silvana Raquel Halac, Luciana Del Valle Mengo, Eduardo Luis Piovano and Gabriela Ana Zanor

Limnol. Rev. 2025, 25(3), 33; https://doi.org/10.3390/limnolrev25030033 - 17 Jul 2025

Abstract

Eutrophication has intensified in lacustrine systems across the American continent, which has been primarily driven by human activities such as intensive agriculture, wastewater discharge, and land-use change. This phenomenon adversely affects water quality, biodiversity, and ecosystem functioning. However, studies addressing the historical evolution [...] Read more.

Eutrophication has intensified in lacustrine systems across the American continent, which has been primarily driven by human activities such as intensive agriculture, wastewater discharge, and land-use change. This phenomenon adversely affects water quality, biodiversity, and ecosystem functioning. However, studies addressing the historical evolution of trophic states in lakes and reservoirs remain limited—particularly in tropical and subtropical regions. In this context, sedimentary records serve as invaluable archives for reconstructing the environmental history of water bodies. Paleolimnological approaches enable the development of robust chronologies to further analyze physical, geochemical, and biological proxies to infer long-term changes in primary productivity and trophic status. This review synthesizes the main methodologies used in paleolimnological research focused on trophic state reconstruction with particular attention to the utility of proxies such as fossil pigments, diatoms, chironomids, and elemental geochemistry. It further underscores the need to broaden spatial research coverage, fostering interdisciplinary integration and the use of emerging tools such as sedimentary DNA among others. High-resolution temporal records are critical for disentangling natural variability from anthropogenically induced changes, providing essential evidence to inform science-based lake management and restoration strategies under anthropogenic and climate pressures. Full article

► Show Figures

Graphical abstract

14 pages, 1209 KiB

Open AccessArticle

Generation of Nitrous Oxide by Aerobic Denitrifiers Isolated from an Urban Wetland in Bogotá, Colombia

by Maribeb Castro-González and Verónica Molina

Limnol. Rev. 2025, 25(3), 32; https://doi.org/10.3390/limnolrev25030032 - 15 Jul 2025

Abstract

In this study, we evaluated the nitrous oxide production potential of denitrifying bacterial strains isolated from sediments of the urban wetland Santa María del Lago under anaerobic and aerobic conditions to determine their potential role in mitigating anthropogenic N₂O emissions, which [...] Read more.

In this study, we evaluated the nitrous oxide production potential of denitrifying bacterial strains isolated from sediments of the urban wetland Santa María del Lago under anaerobic and aerobic conditions to determine their potential role in mitigating anthropogenic N₂O emissions, which have increased by approximately 40% since 1980, and if these emissions could be related to the absence of the nitrous oxide reductase gene (nosZ). The results demonstrated that denitrifying bacteria belonging to the genus Bacillus were able to generate nitrous oxide in high concentrations under both aerobic (up to 83 nM/h) and anaerobic (up to 3865.5 nM/h) conditions in cultures with optimal concentrations of nitrate and carbon. The amplification of the nosZ gene as marker of denitrifying microorganisms showed that only 50% of strains possess this gene, and its presence did not correlate with nitrous oxide reduction under anoxic conditions. Interestingly, one strain was able to reduce nitrous oxide in the presence of air, which is promising for its potential use in aerobic bioremediation systems that require microorganisms with a high affinity for this greenhouse gas to reduce emissions into the atmosphere. Full article

► Show Figures

Figure 1

11 pages, 1969 KiB

Open AccessArticle

Two New Strains of Microcystis Cyanobacteria from Lake Baikal, Russia: Ecology and Toxigenic Potential

by Ekaterina Sorokovikova, Irina Tikhonova, Galina Fedorova, Nadezhda Chebunina, Anton Kuzmin, Maria Suslova, Yanzhima Naidanova, Sergey Potapov, Andrey Krasnopeev, Anna Gladkikh and Olga Belykh

Limnol. Rev. 2025, 25(3), 31; https://doi.org/10.3390/limnolrev25030031 - 10 Jul 2025

Abstract

Microcystis, a potentially toxigenic cyanobacterium known to form extensive blooms in eutrophic lakes globally, was investigated in the cold oligotrophic Lake Baikal. We report the isolation of two Microcystis strains, Microcystis aeruginosa and M. novacekii, and document the presence of the [...] Read more.

Microcystis, a potentially toxigenic cyanobacterium known to form extensive blooms in eutrophic lakes globally, was investigated in the cold oligotrophic Lake Baikal. We report the isolation of two Microcystis strains, Microcystis aeruginosa and M. novacekii, and document the presence of the latter species in Lake Baikal for the first time. In M. aeruginosa strain BN23, we detected the microcystin synthetase gene mcyE. Liquid chromatography-mass spectrometry revealed the presence of two microcystin variants in BN23, with microcystin-LR, a highly potent toxin, being the dominant form. The concentration of MC-LR reached 540 µg/g dry weight. In contrast, M. novacekii strain BT23 lacked both microcystin synthesis genes and detectable toxins. The habitat waters were characterized as oligotrophic with minor elements of mesotrophy, exhibiting low phytoplankton biomass dominated by the chrysophyte Dinobryon cylindricum (76–77% of biomass), with cyanobacteria contributing 8–10%. The contribution of Microcystis spp. to the total phytoplankton biomass could not be quantified as they were exclusively found in net samples. The water temperature at both sampling stations was ~19 °C, which is considerably lower than optimal for Microcystis spp. and potentially conducive to enhanced microcystin production in toxigenic genotypes. Full article

(This article belongs to the Special Issue Trends in the Trophic State of Freshwater Ecosystems)

► Show Figures

Figure 1

15 pages, 528 KiB

Open AccessReview

Water Monitoring Practices 2.0—Water Fleas as Key Species in Ecotoxicology and Risk Assessment

by Anne Leung, Emma Rowan, Flavia Melati Chiappara and Konstantinos Grintzalis

Limnol. Rev. 2025, 25(3), 30; https://doi.org/10.3390/limnolrev25030030 - 2 Jul 2025

Abstract

Humanity faces the great challenges arising from pollution and climate change which evidently lead to the irreversible effects observed on the planet. It is now more important than ever to monitor and safeguard the ecosystem as it has been highlighted by governments and [...] Read more.

Humanity faces the great challenges arising from pollution and climate change which evidently lead to the irreversible effects observed on the planet. It is now more important than ever to monitor and safeguard the ecosystem as it has been highlighted by governments and scientists. Conventional approaches for water pollution rely on the detection of chemicals in the environment. However, these descriptive observations when compared against water quality standards used as metrics for pollution are unable to predict pollution early or capture the extent of its impact. This weakness is reflected in the legislation and the thresholds for emerging pollutants such as pharmaceuticals and nanomaterials. To bridge the gap and to understand the underlying mechanisms for toxicity, research in the field of molecular ecotoxicology shifts more and more towards the integration of model systems, in silico approaches and molecular information as endpoints. Focusing on the freshwater ecosystem, daphnids are key species employed in risk assessment which are characterised as highly responsive to pollutants and physical stressors. The translation of molecular information describing the physiology of these organisms provides novel and sensitive metrics for pollution assessment. Full article

► Show Figures

Figure 1

23 pages, 7993 KiB

Open AccessArticle

A New Machine Learning Algorithm to Simulate the Outlet Flow in a Reservoir, Based on a Water Balance Model

by Marco Antonio Cordero Mancilla, Wilmer Moncada and Vinie Lee Silva Alvarado

Limnol. Rev. 2025, 25(3), 29; https://doi.org/10.3390/limnolrev25030029 - 1 Jul 2025

Abstract

Predicting water losses and final storage in reservoirs has become increasingly relevant in the efficient control and optimization of water provided to agriculture, livestock, industry, and domestic consumption, aiming to mitigate the risks associated with flash floods and water crises. This research aims [...] Read more.

Predicting water losses and final storage in reservoirs has become increasingly relevant in the efficient control and optimization of water provided to agriculture, livestock, industry, and domestic consumption, aiming to mitigate the risks associated with flash floods and water crises. This research aims to develop a new Machine Learning (ML) algorithm based on a water balance model to simulate the outflow in the Cuchoquesera reservoir in the Ayacucho region. The method uses TensorFlow (TF), a powerful interface for graphing and time series forecasting, for data analysis of hydrometeorological parameters (HMP), inflow (QE_obs), and outflow (QS_obs) of the reservoir. The ML water balance model is fed, trained, and calibrated with daily HMP, QE_obs, and QS_obs data from the Sunilla station. The results provide monthly forecasts of the simulated outflow (QS_sim), which are validated with QS_obs values, with significant validation indicators: NSE (0.87), NSE-Ln (0.83), Pearson (0.94), R² (0.87), RMSE (0.24), Bias (0.99), RVB (0.01), NPE (0.01), and PBIAS (0.14), with QS_obs being slightly higher than QS_sim. Therefore, it is important to highlight that water losses due to evaporation and infiltration increased significantly between 2019 and 2023. Full article

(This article belongs to the Special Issue Hot Spots and Topics in Limnology)

► Show Figures

Figure 1

19 pages, 3257 KiB

Open AccessArticle

Total Phosphorus Loadings and Corrective Actions Needed to Restore Water Quality in a Eutrophic Urban Lake in Minnesota, USA: A Case Study

by Neal D. Mundahl and John Howard

Limnol. Rev. 2025, 25(3), 28; https://doi.org/10.3390/limnolrev25030028 - 1 Jul 2025

Abstract

Lake Winona, a 129 ha eutrophic urban lake comprised of two interconnected basins, exceeds state water quality standards for total phosphorus. Historical lake nutrient data and traditional watershed modeling for the lake’s two basins highlighted multiple major pathways (e.g., municipal stormwater discharges, watershed [...] Read more.

Lake Winona, a 129 ha eutrophic urban lake comprised of two interconnected basins, exceeds state water quality standards for total phosphorus. Historical lake nutrient data and traditional watershed modeling for the lake’s two basins highlighted multiple major pathways (e.g., municipal stormwater discharges, watershed runoff, internal loading, and wetland discharges) for total phosphorus (P) loading, with >900 kg P/year estimated entering the water columns of each basin. Updated data sources and newer watershed modeling resulted in significantly different (both higher and lower) P loading estimates for the various P sources, especially watershed runoff and internal loading. Overall, basin-specific loading estimates using the updated model were significantly lower (28–40%) than previous estimates: 680 and 546 kg P/year mobilized in the western and eastern basins, respectively. To achieve state water quality standards (<60 ppm P for the western basin, <40 ppm for the eastern basin), watershed and internal P loading each would need to be reduced by approximately 120 kg P/year across the two basins. Reductions could be achieved by a combination of alum treatments to reduce internal loading, removal of common carp (Cyprinus carpio) to prevent interference with alum treatments and nutrient releases via excretion and defecation, and six engineered structures to intercept P before it enters the lake. The different P reduction projects would cost USD 119 to 7920/kg P removed, totaling USD 5.2 million, or USD 40,310/hectare of lake surface area. Full article

► Show Figures

Figure 1

12 pages, 1726 KiB

Open AccessArticle

Annual and Seasonal Trends in Density, Biomass, and Secondary Production of Chironomid Midges (Diptera: Chironomidae) in the Middle Reaches of the Shinano River, Japan, 2015–2019

by Kimio Hirabayashi

Limnol. Rev. 2025, 25(2), 27; https://doi.org/10.3390/limnolrev25020027 - 6 Jun 2025

Abstract

The dipteran family Chironomidae is the most widely distributed and, frequently, the most abundant group of insects in freshwater environments. Ecologically, the group plays an important role in trophic cycles and detritus processing in aquatic ecosystems and can be the most productive group [...] Read more.

The dipteran family Chironomidae is the most widely distributed and, frequently, the most abundant group of insects in freshwater environments. Ecologically, the group plays an important role in trophic cycles and detritus processing in aquatic ecosystems and can be the most productive group of secondary producers in running waters. The annual secondary production of Chironomidae was estimated using emergence trap data from riffles and pools from two stations on the middle reaches of the Shinano River: Tokida Bridge Area (slope 1/180) and Iwano Bridge Area (1/1000). Emergence traps were set up for 24 h on the river’s water surface at three points each in the riffles and pools monthly from April 2015 to March 2019. Five subfamilies of Chironomidae were recorded during the investigation period: Chironominae, Orthocladiinae, Tanypodinae, Diamesinae, and Prodiamesinae. In the Shinano River (Tokida + Iwano area), Orthocladiinae and Diamesinae were the dominant subfamilies in terms of both density (63.2% and 19.0%, respectively) and biomass (62.2% and 25.2%, respectively). Each year’s annual secondary production measured as ash free dry weight (AFDW) was 11.33–55.04 g/m²/year in Tokida and 5.83–38.43 g/m²/year in Iwano. The average annual secondary production of detritus feeder Chironomidae (all except for Tanypodinae) was 24.46 ± 20.38 (ranging from 11.13 in 2015 to 54.67 in 2018) in the Tokida area and 19.61 ± 16.38 (ranging from 5.41 in 2016 to 37.53 in 2017) in the Iwano area. On the other hand, that of carnivorous Chironomidae (Tanypodinae) was 0.22 ± 0.10 (ranging from 0.13 in 2016 to 0.37 in 2018) in the Tokida area and 0.66 ± 0.24 (ranging from 0.42 in 2016 to 0.90 in 2017) in the Iwano area, and overall secondary production averaged 22.48 g/m²/year in the middle reaches of the Shinano River. These values were higher than in previous reports. Full article

► Show Figures

Graphical abstract

19 pages, 1662 KiB

Open AccessArticle

Environmental Changes as a Factor in the Dynamics of Aquatic Vegetation Distribution in Belarusian Soft-Water Lakes

by Nina Sukhovilo, Daria Vlasova, Aliaksei Novik and Boris Vlasov

Limnol. Rev. 2025, 25(2), 26; https://doi.org/10.3390/limnolrev25020026 - 5 Jun 2025

Abstract

This article describes the reasons for and trends in the overgrowth of soft-water lakes in Belarus. Due to their unique water properties (low mineralization, pH, and nitrogen and phosphorus concentrations) and high water transparency, soft-water lakes are home to protected plant species like [...] Read more.

This article describes the reasons for and trends in the overgrowth of soft-water lakes in Belarus. Due to their unique water properties (low mineralization, pH, and nitrogen and phosphorus concentrations) and high water transparency, soft-water lakes are home to protected plant species like Lobelia dortmanna L., Isöetes lacustris L., and Littorella uniflora L. The purpose of this study was to analyze changes in aquatic vegetation distribution in seven soft-water Belarusian lakes and identify the causes of these changes. The initial data for this research were the results of field observations, the archive materials of the research laboratory of lake research conducted by the Belarusian State University for the period from 1971 to 2016, including morphometric and hydrochemical parameters, the characteristics of catchments and water exchange, and the results of studying the species composition and distribution of aquatic vegetation. The authors’ field studies were carried out in 2022–2024. We used expeditionary, hydrochemical, cartographic, and comparative research methods. The most significant changes in overgrowth were observed in Lakes Svityaz and Beloe (Luninets District). These lakes have high recreational loads. Significant negative trends were also noted in Lakes Bolshoe Ostrovito and Bredno. Over 35 years, the depth of distribution of submerged macrophytes in Lake Svityaz has decreased from 7 to 2 m, and the abundance and projective cover of semi-submerged macrophytes have increased. In Lake Beloe, I. lacustris, which forms a tier of submerged plants, has almost completely disappeared, and a previously absent strip of air-aquatic plants has formed. The total area of overgrowth in the lake has decreased from 35% of the water area to 3.2%. In Lake Bolshoe Ostrovito, Fontinalis sp., previously common at depths of up to 5 m, has practically disappeared. In Lake Bredno, the water moss Drepanocladus has spread to a depth of 4 m. In Lake Glubokoe, a new area of I. lacustris growth was discovered around an island at depths of up to 4 m. In Lake Cherbomyslo, the decrease in the species’ depth and area of distribution is associated with a weakening of the inflow of bog waters due to their backwater. The main causes of these changes are largely due to anthropogenic factors (water pollution by biogenic compounds) and, to a lesser extent, hydrological changes (decrease in the moisture content of lake catchments). Full article

► Show Figures

Figure 1

13 pages, 398 KiB

Open AccessArticle

Challenges in Phosphorus Removal from Eutrophic Waters Using Adsorption: A Laboratory Comparison of Commercial and Moringa-Derived Adsorbents

by Daniela Resende Duque, Adriano Gonçalves dos Reis, Jorge Kennety Silva Formiga and Suzelei Rodgher

Limnol. Rev. 2025, 25(2), 25; https://doi.org/10.3390/limnolrev25020025 - 3 Jun 2025

Abstract

To reduce the concentration of phosphorus, the main nutrient responsible for eutrophication, two adsorbents were tested: a commercial activated carbon and one produced from the pods of Moringa oleifera. A concentrated phosphorus solution representative of eutrophic ecosystems was produced at 0.210 mg·L [...] Read more.

To reduce the concentration of phosphorus, the main nutrient responsible for eutrophication, two adsorbents were tested: a commercial activated carbon and one produced from the pods of Moringa oleifera. A concentrated phosphorus solution representative of eutrophic ecosystems was produced at 0.210 mg·L⁻¹ and used as the adsorbate. Thirty-nine laboratory samples were prepared with adsorbent dosages ranging from 0.5 g∙L⁻¹ to 2.0 g∙L⁻¹, and statistical analyses were applied to evaluate the results. An increase in the concentration of phosphorus in the solution was detected in all the tests. Desorption occurred due to the presence of nutrients in the composition of the adsorbents, in addition to the mild physical activation and the use of H₃PO₄ as a chemical activator of the natural adsorbent, which further favored desorption at equilibrium, even for activated carbon. This work, therefore, highlights the limitations of using the adsorption technique to remove phosphorus from eutrophic aquatic ecosystems. It is recommended that other activation methods for M. oleifera pods be studied for phosphorus removal from water, as well as adsorption equilibrium, kinetics, and thermodynamic studies. Full article

► Show Figures

Figure 1

19 pages, 2272 KiB

Open AccessArticle

Environmental Pollution and Biological Invasions Threaten Native Freshwater Infaunal Bivalves in the Guandu River Basin, Southeast Brazil

by Nathália Rodrigues, Igor C. Miyahira, Antonio J. S. Rodrigues, Luciano N. Santos and Raquel A. F. Neves

Limnol. Rev. 2025, 25(2), 24; https://doi.org/10.3390/limnolrev25020024 - 3 Jun 2025

Abstract

Freshwater bivalves play essential ecological roles in ecosystems, but they are among the most threatened fauna worldwide. Despite receiving industrial and domestic wastes, the Guandu River is the main source of drinking water for more than nine million people in the Rio de [...] Read more.

Freshwater bivalves play essential ecological roles in ecosystems, but they are among the most threatened fauna worldwide. Despite receiving industrial and domestic wastes, the Guandu River is the main source of drinking water for more than nine million people in the Rio de Janeiro metropolitan region. This study aimed to assess how infaunal bivalves respond to water and sediment quality in the Guandu River basin. Samples were collected at 10 sites across reservoirs, lotic, and lentic systems during cold–dry and warm–rainy seasons. Four bivalves were identified: Anodontites trapesialis, Diplodon ellipticus, Corbicula fluminea (non-native), and C. largillierti (non-native). Native species were restricted to two lentic sites at Guandu Lagoon, with the poorest environmental quality, significantly affected by high chlorophyll a and ammonia in the water. In contrast, C. fluminea was widely distributed and more abundant in the basin but restricted to less degraded sites, suggesting a lower tolerance to environmental pollution. Multivariate analyses indicated significant differences in environmental conditions and species–environment correlation. The non-native species spread and poor environmental quality threaten native bivalves in the Guandu River basin, leading them to a local extinction risk. Results highlight the need for effective management and conservation actions to protect biodiversity in tropical river basins. Full article

► Show Figures

Figure 1

17 pages, 775 KiB

Open AccessReview

Ferrochrome Pollution and Its Consequences on Groundwater Ecosystems and Public Health

by Biswajit Patra, Mihir Tanay Das, Surya Narayan Pradhan, Soumya Ranjan Dash, Prajna Paramita Bhuyan and Biswajita Pradhan

Limnol. Rev. 2025, 25(2), 23; https://doi.org/10.3390/limnolrev25020023 - 2 Jun 2025

Abstract

Ferrochrome pollution, a by-product of the ferroalloy industry, is emerging as a significant environmental concern due to its potential to contaminate groundwater resources. This contamination occurs primarily through the leaching of heavy metals, such as chromium, into the soil and water systems. This [...] Read more.

Ferrochrome pollution, a by-product of the ferroalloy industry, is emerging as a significant environmental concern due to its potential to contaminate groundwater resources. This contamination occurs primarily through the leaching of heavy metals, such as chromium, into the soil and water systems. This review article presents a strategic framework for assessing environmental and health risks associated with the ferrochrome industry pollution rather than focusing on a case study. The suggested methodology is designed to guide future field investigations in areas impacted by ferrochrome industrial activities. The presence of chromium in groundwater poses serious risks to both ecosystems and human health. In aquatic ecosystems, elevated chromium levels can disrupt the balance of microbial communities, affect biodiversity, and harm aquatic organisms. For humans, long-term exposure to chromium-contaminated groundwater is associated with a range of health issues, including carcinogenic effects, skin rashes, respiratory problems, and potential damage to vital organs. The widespread use of groundwater for drinking, irrigation, and industrial purposes exacerbates the risks to public health. This paper explores the sources, pathways, and mechanisms of ferrochrome contamination, examines its impact on groundwater ecosystems, and highlights the health consequences for affected populations. Strategies for mitigating ferrochrome pollution, including treatment technologies and policy interventions, are also discussed to help safeguard both environmental and public health. Full article

► Show Figures

Figure 1

11 pages, 2071 KiB

Open AccessArticle

Vegetative and Reproductive Allocation in an Aquatic Macrophyte: The Effects of Light, Nutrients, and Epiphytic Heterocytous Cyanobacteria

by Michel Biondi, Larissa Langsdorff Pimenta, Gabriela Costa Rodrigues, Gustavo Pereira Lima, Marcelo Gomes Marçal Vieira Vaz and Flávia de Freitas Coelho

Limnol. Rev. 2025, 25(2), 22; https://doi.org/10.3390/limnolrev25020022 - 6 May 2025

Abstract

The study evaluated the vegetative growth and reproductive strategies of the macrophyte Pistia stratiotes under varying nutrient (carbon and nitrogen) and light (full sun and 70% shade) conditions, as well as its epiphytic association with heterocytous cyanobacteria. Plants were collected from a reservoir, [...] Read more.

The study evaluated the vegetative growth and reproductive strategies of the macrophyte Pistia stratiotes under varying nutrient (carbon and nitrogen) and light (full sun and 70% shade) conditions, as well as its epiphytic association with heterocytous cyanobacteria. Plants were collected from a reservoir, transferred to a greenhouse, and subjected to six treatments, with sampling every 15 days. Clonal growth was higher in nitrogen-supplemented treatments, while flowering was more pronounced in carbon-supplemented treatments. Heterocyte production by epiphytic cyanobacteria on roots positively correlated with P. stratiotes total biomass, suggesting the macrophyte utilizes nitrogen fixed by periphytic cyanobacteria. The results highlight the importance of nitrogen and carbon for growth and reproduction, with distinct resource allocation for rosettes (nitrogen) and flowers (carbon). The P. stratiotes-cyanobacteria association may enhance macrophyte population expansion, underscoring the ecological role of these microorganisms. Full article

► Show Figures

Graphical abstract

12 pages, 1680 KiB

Open AccessArticle

Assessment of Water Quality and Presence of Enterobacteria in the Billings-Tamanduateí Watershed and Its Relationship with Social Indicators

by Beatriz Guedes-Pereira, Romeu Randefran Souza Dantas, Juliana Mendonça Silva de Jesus, Isabela Gagliardi Ortiz, Gabrielle Segatti Soares Almeida, Rodrigo de Freitas Bueno, Luís César Schiesari and Ricardo Hideo Taniwaki

Limnol. Rev. 2025, 25(2), 21; https://doi.org/10.3390/limnolrev25020021 - 6 May 2025

Abstract

Water quality in urban streams is closely linked to socioeconomic conditions, particularly in densely populated and poorly sanitized areas. This study evaluates the physicochemical and microbiological quality of water in the Billings-Tamanduateí sub-basin and investigates its correlation with social indicators such as population [...] Read more.

Water quality in urban streams is closely linked to socioeconomic conditions, particularly in densely populated and poorly sanitized areas. This study evaluates the physicochemical and microbiological quality of water in the Billings-Tamanduateí sub-basin and investigates its correlation with social indicators such as population density, informal settlements, and lack of sewage treatment. Water samples were collected from 14 sub-basins, analyzing parameters, including dissolved organic and inorganic carbon, total dissolved nitrogen, pH, dissolved oxygen, oxidation-reduction potential, conductivity, and the presence of enterobacteria (Escherichia coli, Enterococcus, and Pseudomonas aeruginosa). Statistical analyses revealed strong associations between water quality degradation and increased population density, lack of sanitation, and lower per capita income. The findings reinforce that socially vulnerable areas are the most affected, with higher levels of organic and microbiological contamination. Despite improvements in sewage collection over time, gaps in wastewater management persist, even in major metropolitan areas such as São Paulo. Future studies could expand the analysis to include less vulnerable regions for comparison and explore the impacts of climate change on urban stream water quality. The results highlight the urgent need for improved sanitation infrastructure and policies to mitigate contamination and protect public health. Full article

► Show Figures

Graphical abstract

25 pages, 936 KiB

Open AccessArticle

Fish Genetic Resources and Wetland Conservation in Bangladesh: Comparative Insights on Biodiversity, Sustainable Management, and Sustainable Development Goals

by Atiqur Rahman Sunny, Sharif Ahmed Sazzad, Md Shishir Bhuyian, Md. Nazmul Hasan, Md. Faruque Miah, Md. Ashrafuzzaman and Shamsul Haque Prodhan

Limnol. Rev. 2025, 25(2), 20; https://doi.org/10.3390/limnolrev25020020 - 3 May 2025

Cited by 1

Abstract

Background: Bangladesh’s wetlands support fish genetic resources, biodiversity, and food security but face obstacles like habitat degradation, overfishing, and climate change. This research looks at the diversity, abundance, IUCN conservation status, and stakeholder views for sustainable wetland management in three major wetlands: the [...] Read more.

Background: Bangladesh’s wetlands support fish genetic resources, biodiversity, and food security but face obstacles like habitat degradation, overfishing, and climate change. This research looks at the diversity, abundance, IUCN conservation status, and stakeholder views for sustainable wetland management in three major wetlands: the Sundarbans mangrove (brackish water), the Sylhet floodplain (freshwater), and the Meghna River basin (estuary). Methods: To assess ecosystem health and vulnerability, we assess fish biodiversity and conservation status using Margalef’s Species Richness Index and Shannon–Weaver Diversity Index. We also used structured questionnaires to interview and gain stakeholders’ perceptions. Results: A total of 165 fish species were identified and categorized based on the IUCN Red List. The Sundarbans exhibited the highest species richness and diversity. The proportion of vulnerable species was highest in Sylhet (15%), followed by the Sundarbans (12%) and Meghna (9%), while 54% of fish species in Sylhet, 36% in the Sundarbans, and 26% in Meghna were not threatened. This study emphasizes integrated wetland management solutions that support SDGs 2 (Zero Hunger), 14 (Life Below Water), and 15 (Life on Land) as outlined by the Food and Agriculture Organization (FAO). Conclusion: Findings provide a foundation for policymakers, researchers, and conservationists to develop sustainable wetland management frameworks that safeguard fish genetic resources, livelihoods, and ecological balance. Full article

► Show Figures

Graphical abstract

12 pages, 1479 KiB

Open AccessArticle

Erythrocyte Micronuclei and Nuclear Abnormalities in Three Species of Fish from Lake Piediluco (Central Italy)

by Valentina Battistelli, Leonardo Brustenga, Gianandrea La Porta, Mattia Baccianella and Livia Lucentini

Limnol. Rev. 2025, 25(2), 19; https://doi.org/10.3390/limnolrev25020019 - 1 May 2025

Cited by 1

Abstract

The frequencies of both micronuclei (Mn) and nuclear abnormalities (NAs) were determined in peripheral blood smears of European perch (Perca fluviatilis), rudd (Scardinius erythrophthalmus), and pikes (genus Esox) from Lake Piediluco (Central Italy). Given the conformation of the [...] Read more.

The frequencies of both micronuclei (Mn) and nuclear abnormalities (NAs) were determined in peripheral blood smears of European perch (Perca fluviatilis), rudd (Scardinius erythrophthalmus), and pikes (genus Esox) from Lake Piediluco (Central Italy). Given the conformation of the lake, all the animals from the three species were equally exposed to the same natural stressors. To assess the different stress responses in the three species, 20 blood smears per specimen from each species were analyzed, counting the micronuclei and nuclear aberration present over a total of 1000 erythrocytes for each slide. Different responses to stress were recorded in the three species, with P. fluviatilis exhibiting the least amount of both Mn (0.42%) and NAs (0.01%), and therefore the better homeostasis, while the majority of Mn and NAs were recorded in Esox spp. (Mn: 3.88%; NAs: 23.18%). No MN were observed in S. erythrophthalmus, so that might not be an adequate species to apply the micronucleus test, and it also presented a lower percentage of NAs (15.32%) compared to the pike samples. This work provides, for the first time, baseline values of erythrocyte micronuclei and nuclear aberration from natural populations of the three fish species in a lake from Central Italy. Full article

► Show Figures

Figure 1

20 pages, 2134 KiB

Open AccessArticle

Diatoms of Gut Content of Crassostrea gasar (Bivalvia: Ostreidae) (Adanson, 1757) Cultivated in an Amazonian Estuary (Emboraí Velho, Northern Brazil)

by Barbara de Fátima Oliveira da Silva, Antonio Rafael Gomes de Oliveira, João Victor de Moraes Souza Pinheiro, Brenda Ribeiro Padilha da Silva, Remo Luan Marinho da Costa Pereira, Luci Cajueiro Carneiro Pereira and Rauquírio Marinho da Costa

Limnol. Rev. 2025, 25(2), 18; https://doi.org/10.3390/limnolrev25020018 - 1 May 2025

Abstract

The present study investigated the gut contents of oysters cultivated in the Emboraí Velho Estuary (Amazonian littoral), focusing on the analysis of diatoms. Analyses of the stomach contents from 60 adult individuals of the species Crassostrea gasar (Adanson, 1757) collected in the study [...] Read more.

The present study investigated the gut contents of oysters cultivated in the Emboraí Velho Estuary (Amazonian littoral), focusing on the analysis of diatoms. Analyses of the stomach contents from 60 adult individuals of the species Crassostrea gasar (Adanson, 1757) collected in the study environment were performed. Additional water samples were collected for the analysis of diatoms present in the estuary. The total number of diatom taxa identified in the estuary was 123, with 35.8% centric diatoms and 64.2% pennate diatoms. Organisms recorded in the analyzed oyster stomachs comprised 61 taxa, of which 37.7% were centric and 62.3% pennate diatoms. The relative abundance of Cymatosira belgica Grunow was 78.2% in April, 72.1% in June, 51.9% in September, and 91.8% in December in the estuary. However, in the gut content, it was 9.9% in April, 4.3% in June, 13.9% in September, and 45.1% in December. The relative abundance of C. belgica, as well as of other less abundant species, was not similar between the gut contents and the diatom species identified in the estuary. Our results indicate that cultivated oysters selectively feed on certain diatom species identified in the estuary, as the main species recorded in the gut contents were not similar to the most abundant and frequent species found in the estuary during the same months of the present study. Full article

► Show Figures

Figure 1

11 pages, 628 KiB

Open AccessArticle

Influence of the Level of the Middle River Negro in the Amazon, Brazil, on the Properties of the Blood of the Cururu Freshwater Stingray Potamotrygon wallacei

by Adriano Teixeira de Oliveira, Ariany Rabello da Silva Liebl, Maria Fernanda da Silva Gomes, Maiko Willas Soares Ribeiro, Rayana Melo Paixão, Antônia Jaqueline Vitor Paiva, Suelen Miranda dos Santos, João Paulo Ferreira Rufino, Junior Ribeiro Carvalho and Paulo Henrique Rocha Aride

Limnol. Rev. 2025, 25(2), 17; https://doi.org/10.3390/limnolrev25020017 - 1 May 2025

Abstract

Amazonian fishes, as an adaptive form to the annual flood cycle, develop physiological strategies to adjust to variations in their habitats. The results of this study help to understand how freshwater stingrays adapt to changes in river levels and allow us to predict [...] Read more.

Amazonian fishes, as an adaptive form to the annual flood cycle, develop physiological strategies to adjust to variations in their habitats. The results of this study help to understand how freshwater stingrays adapt to changes in river levels and allow us to predict the physiology of blood and water properties in situations of extreme droughts and floods in rivers. This study aimed to evaluate the physiological characteristics of the freshwater stingray Potamotrygon wallacei in response to seasonal variations in the Middle River Negro, analyzing the effects of these changes on its hematological and biochemical parameters and investigating the relationship between these changes and the physicochemical composition of the water. The animals were captured in lakes and marshes in the Mariuá Archipelago in River Negro. Five field collections were carried out during periods of different flood pulses. Blood was collected by puncture of the gill vessel after the animals were anesthetized. Hematological parameters were determined by routine methods for stingrays. Blood parameters reveal close relationships with changes in river levels, which occur throughout a hydrological cycle in the Middle River Negro region. Therefore, this indicates that the hematology of P. wallacei can be used in monitoring, indicating modifications of adverse environmental changes; however, this ecophysiological association is a complex process and needs to be further investigated. Full article

► Show Figures

Figure 1

Journal Description

Limnological Review

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Further Information

Guidelines

MDPI Initiatives

Follow MDPI