Limnological Review

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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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20 pages, 1383 KiB

Open AccessArticle

Nutrient, Organic Matter and Shading Alter Planktonic Structure and Density of a Tropical Lake

by Marina Isabela Bessa da Silva, Luciana Pena Mello Brandão, Ludmila Silva Brighenti, Peter A. U. Staehr, Cristiane Freitas de Azevedo Barros, Francisco Antônio Rodrigues Barbosa and José Fernandes Bezerra-Neto

Limnol. Rev. 2025, 25(2), 16; https://doi.org/10.3390/limnolrev25020016 - 29 Apr 2025

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Abstract

The structure and density of plankton communities greatly influence carbon and nutrient cycling as well as the environmental status of lake ecosystems. This community can respond to a range of environmental drivers, including those influenced by human perturbations on local and regional scales, [...] Read more.

The structure and density of plankton communities greatly influence carbon and nutrient cycling as well as the environmental status of lake ecosystems. This community can respond to a range of environmental drivers, including those influenced by human perturbations on local and regional scales, causing abrupt changes and imbalances. While the implications of climate and land-use changes are evident for a range of tropical lake conditions, their impacts on planktonic population dynamics are less understood. In this study, we aimed to investigate how distinctive levels of nutrients, allochthonous organic matter (OM), and sunlight availability change phytoplankton and zooplankton density and structure in a natural tropical lake. Using an in situ mesocosm facility, we manipulated the addition of nutrients and OM, in addition to sunlight availability and a combination of these treatments. We monitored limnological parameters, plankton count, and identification for 12 days. The mesocosms included eight different combinations in a 2 × 2 × 2 factorial design, each with two replicates. Inorganic nutrient addition reduced phytoplankton species richness, favoring the dominance of opportunistic species such as Chlorella sp. at much higher densities. Organic matter also increased light attenuation and caused the substitution of species and changes in dominance from Pseudanabaena catenata to Aphanocapsa elachista. On the other hand, physical shading had less influence on these communities, presenting densities similar to those found in the control mesocosms. Zooplankton presented a group dominance substitution in all mesocosms from copepod to rotifer species, and copepod growth seemed to be negatively affected by Chlorella sp. density increase. Furthermore, this community was associated with the light attenuation indices and bacterioplankton. These results indicate that tropical planktonic responses to environmental changes can effectively occur in just a few days, and the responses can be quite different depending on the nutritional source added. The punctual nutrient addition was sufficient to provide changes in this community, evidencing the strength of anthropic events associated with strong nutrient input. Understanding tropical plankton dynamics in response to environmental changes, such as those simulated in this work, is important for understanding the effects of climate and anthropogenic changes on tropical lake functioning. This knowledge can strengthen measures for the conservation of freshwater systems by allowing predictions of plankton community changes and the possible consequences for the aquatic food chain and water quality. Full article

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17 pages, 3688 KiB

Open AccessArticle

Reaeration Coefficient Empirical Equation Selection for Water Quality Modeling in Surface Waterbodies: An Integrated Numerical-Modeling-Based Technique with Field Case Study

by Balsam J. M. Al-Saadi and Hussein A. M. Al-Zubaidi

Limnol. Rev. 2025, 25(2), 15; https://doi.org/10.3390/limnolrev25020015 - 25 Apr 2025

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Abstract

Empirical equations were developed by many investigators to determine the reaeration coefficients (Ka) required for predicting dissolved oxygen concentrations (DO) in surface waters, especially rivers, lakes, and reservoirs. However, these equations yield a wide range of Ka values. In this paper, an integrated [...] Read more.

Empirical equations were developed by many investigators to determine the reaeration coefficients (Ka) required for predicting dissolved oxygen concentrations (DO) in surface waters, especially rivers, lakes, and reservoirs. However, these equations yield a wide range of Ka values. In this paper, an integrated numerical-modeling-based technique was developed to check the validity of the equations before using them in water quality modeling for rivers, lakes, and reservoirs. Depending on direct field measurements at the Hilla River headwater (Saddat Al-Hindiyah Reservoir, Iraq), the temporal oxygen mass transport at the water surface was estimated numerically by solving the one-dimensional advection diffusion equation and then using each Ka empirical equation separately in the numerical model obtained the best specific-waterbody equation. The DO modeling results showed that using a reservoir reaeration coefficient of 0.1 day⁻¹ at 20 °C predicts the best DO simulation with low MAEs of 0.4987 and 0.7880 mg/L during the study years 2021 and 2022, respectively, compared to the field data. However, using the Ka empirical equations simulates the DO with wide-ranging statistical errors even though the temporal Ka values have a similar trend during the year. It was noticed that the empirical equations produced maximum Ka values of (0.0080–0.0967 day⁻¹) and minimum Ka values of (0.00052–0.0267 day⁻¹) in 2021 and maximum Ka values of (0.0079 to 0.0951 day⁻¹) and minimum Ka values of (0.00012 and 0.0231 day⁻¹) in 2022. The present equation selection technique revealed that Broecker et al.’s equation followed by Smith’s equation, developed in 1978, are the best selection for water quality modeling at the Hilla River headwater (MAEs: 0.1347 and 0.1686 mg/L in 2021, respectively; and MAEs: 0.1400 and 0.1744 mg/L in 2022, respectively). Hence, it is necessary to find good agreement for the equation-based prediction of DO, DO source–sink, and Ka values compared to the validated model before making selection. Full article

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22 pages, 3150 KiB

Open AccessArticle

Influence of Experimental Eutrophication on Macrozoobenthos in Tufa-Depositing System of Plitvice Lakes National Park, Croatia

by Maja Vurnek and Renata Matoničkin Kepčija

Limnol. Rev. 2025, 25(2), 14; https://doi.org/10.3390/limnolrev25020014 - 17 Apr 2025

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Abstract

The process of tufa deposition created the Plitvice Lakes, a unique freshwater cascade system of 16 lakes separated by tufa barriers. This complex karst hydrosystem reacts very sensitively to even small changes, and eutrophication can directly and indirectly affect tufa formation. With the [...] Read more.

The process of tufa deposition created the Plitvice Lakes, a unique freshwater cascade system of 16 lakes separated by tufa barriers. This complex karst hydrosystem reacts very sensitively to even small changes, and eutrophication can directly and indirectly affect tufa formation. With the purpose of determining the influence of nitrogen (N) and phosphorus (P) on periphyton’s chlorophyll a concentration, tufa deposition, and macrozoobenthos, we used nutrient-diffusing substrates. The in situ experiment combined the effects of seasons, stronger/weaker tufa deposition, and the presence/absence of macrophytes. The season was the dominant factor influencing hydrology, physicochemical factors, tufa deposition, and the effects of eutrophication. Phosphorus was the limiting factor for periphyton developing on artificial substrates, as evidenced by the highest chlorophyll a level on P and N+P substrates. Lower tufa deposition supported a higher chlorophyll a level, while macrophytes reduced the chlorophyll a concentration and tufa deposition, possibly through effects on the flow and via root respiration. The effects of nutrients on tufa deposition were not recorded. P and N+P treatment increased macrozoobenthos abundance only in some seasons. Trophic groups of macrozoobenthos responded to the addition of P and N+P in the form of higher proportions of gazers and detritivores; however, the response of macrozoobenthos was generally weaker than that of autotrophs. Full article

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14 pages, 2012 KiB

Open AccessArticle

Impact of Sugarcane Cultivation on Benthic Macroinvertebrate Communities in Tropical Streams

by Marcus Vinícius França, Erika Mayumi Shimabukuro, Welber Senteio Smith, Mariana Morilla and Ricardo Hideo Taniwaki

Limnol. Rev. 2025, 25(2), 13; https://doi.org/10.3390/limnolrev25020013 - 16 Apr 2025

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Abstract

Tropical streams host diverse benthic macroinvertebrates, essential for ecological processes and bioindicators of ecosystem health. However, land use changes, such as sugarcane cultivation, negatively impact stream structure and function. This study examined these effects by comparing streams in sugarcane-dominated areas with those in [...] Read more.

Tropical streams host diverse benthic macroinvertebrates, essential for ecological processes and bioindicators of ecosystem health. However, land use changes, such as sugarcane cultivation, negatively impact stream structure and function. This study examined these effects by comparing streams in sugarcane-dominated areas with those in native vegetation. Streams with native vegetation showed 2226 individuals across 107 taxa, 39 families, and 52 genera, with Chironomidae (Chironominae, Tanypodinae), Leptoceridae, Leptophlebiidae, and Calamoceratidae being the most abundant. In contrast, sugarcane streams showed 692 individuals from 47 taxa, 24 families, and 19 genera, with Chironomidae (Chironominae, Tanypodinae), Dryopidae, and Simuliidae dominating. The first hypothesis suggested that sugarcane plantations reduce taxonomic and functional diversity. The results partially confirmed this, showing lower abundance and richness in sugarcane streams, though functionality remained unchanged. The second hypothesis proposed greater seasonal taxonomic variation in sugarcane streams due to hydrological differences. Results supported this, revealing stronger seasonal shifts, particularly during the rainy season. These findings highlight the significant impact of sugarcane cultivation on aquatic ecosystems. Continuous monitoring of macroinvertebrates in agricultural landscapes is crucial for assessing environmental impacts and guiding conservation strategies. Full article

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13 pages, 2194 KiB

Open AccessArticle

Elemental Associations with Groundwater Nitrate in Northeastern Region of Saudi Arabia: Implications for Sustainable Water Management

by Al Mamun

Limnol. Rev. 2025, 25(2), 12; https://doi.org/10.3390/limnolrev25020012 - 1 Apr 2025

Viewed by 492

Abstract

Nitrate pollution in drinking water is a major environmental and health issue. High levels of nitrates in water sources present serious risks to both the environment and public health, highlighting the need for immediate research and management efforts to reduce pollution sources and [...] Read more.

Nitrate pollution in drinking water is a major environmental and health issue. High levels of nitrates in water sources present serious risks to both the environment and public health, highlighting the need for immediate research and management efforts to reduce pollution sources and safeguard water resources for sustainable growth. This study investigates the elemental associations with nitrate concentrations in groundwater across the northeastern region of Saudi Arabia, employing diverse analytical techniques to assess water quality and develop sustainable management strategies. Spatial variations in nitrate levels were observed in both deep and shallow wells using GIS-based interpolation, revealing distinct patterns influenced by geological, hydrological, and anthropogenic factors. A strong linear correlation with a high coefficient of determination (R² of 0.99) between electrical conductivity and dilution factor suggests the potential interchangeability of ion-selective electrode methods and conductivity meters for EC determination. The study identified a positive correlation between nitrate concentration and electrical conductivity in groundwater samples (R² of 0.70), indicating that conductivity measurements could potentially serve as a proxy for estimating nitrate levels. However, a very weak negative correlation between nitrate and pH suggests other factors may have a more significant impact on groundwater pH. The research also highlights the strong positive correlation between nitrate and nitrate-nitrogen concentrations, reflecting their close chemical association in water. These findings contribute to the understanding of nitrate dynamics in groundwater and emphasize the importance of comprehensive water quality assessments. Future research should focus on elucidating factors influencing nitrate distribution in groundwater systems and developing more robust predictive models based on readily measurable water quality parameters. Full article

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18 pages, 4254 KiB

Open AccessArticle

Species-Specific Responses of Baikal Amphipods to Artificial Lighting of Varying Intensity and Spectral Composition

by Dmitry Karnaukhov, Yana Ermolaeva, Maria Maslennikova, Bogdan Osadchy, Sofya Biritskaya, Arina Lavnikova, Natalia Kulbachnaya, Anastasia Solodkova, Artem Guliguev, Ivan Kodatenko, Diana Rechile, Kristina Ruban, Darya Kondratieva, Alexandr Bashkirtsev, Alyona Slepchenko, Anna Solomka, Sophia Nazarova and Eugene Silow

Limnol. Rev. 2025, 25(2), 11; https://doi.org/10.3390/limnolrev25020011 - 1 Apr 2025

Cited by 1 | Viewed by 377

Abstract

Light pollution can have a variety of effects on aquatic organisms. Despite the fact that amphipods are one of the model organisms for studying the effects of light among macroinvertebrates, data on the reaction of Baikal amphipods to artificial lighting are limited and [...] Read more.

Light pollution can have a variety of effects on aquatic organisms. Despite the fact that amphipods are one of the model organisms for studying the effects of light among macroinvertebrates, data on the reaction of Baikal amphipods to artificial lighting are limited and contradictory. In this study, we examine the response of Baikal littoral and sublittoral amphipod species to artificial lighting of varying intensity and spectral composition. In the experiments, amphipods were exposed to warm and white light at three different intensity ranges (5–15, 20–35, and 80–100 lx), as well as blue and red light. As a result, it was found that the reaction of Baikal amphipods to different lighting conditions was species-specific and dependent on the spectral composition of the light more so than the intensity of the light. In particular, white LED light generally repulsed E. cyaneus, but tended to attract A. godlevskii. P. cancelloides, and G. fasciatus, suggesting that white LED light may have a greater negative impact on wildlife than warm LED light. Generally, artificial light influences the behavior of Baikal amphipods, and an increase in light pollution on Lake Baikal may lead to changes in the littoral community in certain areas of the lake subject to pollution. Full article

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16 pages, 4604 KiB

Open AccessArticle

Historical Phosphorus Kinetics and Ambient Orthophosphate Concentrations in the St. Lawrence Great Lakes Erie, Huron, Michigan, St. Clair, and Superior by a Modified Inverse Isotope Dilution Method

by John T. Lehman

Limnol. Rev. 2025, 25(2), 10; https://doi.org/10.3390/limnolrev25020010 - 21 Mar 2025

Cited by 1 | Viewed by 308

Abstract

Historical measurements of phosphate turnover and uptake confirm that bacterioplankton dominate phosphate dynamics at ambient steady state conditions in all but the most eutrophic samples, but phytoplankton exhibits increased control at phosphate additions as low as +10 nM. The results are consistent with [...] Read more.

Historical measurements of phosphate turnover and uptake confirm that bacterioplankton dominate phosphate dynamics at ambient steady state conditions in all but the most eutrophic samples, but phytoplankton exhibits increased control at phosphate additions as low as +10 nM. The results are consistent with the theory that uptake mechanisms of bacterioplankton become saturated as soon as phosphate concentrations are elevated above ambient levels. Uptake dynamics were consistent with multiphasic kinetics by bacterioplankton versus phytoplankton. Temperature dependence of phosphate turnover was demonstrated for Lake Superior but not for other Great Lakes in which temperatures were largely homogeneous. Ambient concentrations of orthophosphate were estimated by an inverse isotope dilution method that indicated concentrations ranged from roughly 1 to 7 nM across all the lakes surveyed. Full article

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Limnol. Rev., Volume 25, Issue 2 (June 2025) – 18 articles

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