Lentic Research Articles

Diversity and Conservation of Wetland Avifauna in Nanjarayan Lake, Tiruppur, Tamil Nadu, India

This paper shares the results from a big bird survey at Nanjarayan Lake in Tamil Nadu. It ran from 2022 to 2024. To check out the bird variety, see how it changes with the seasons and look at how well different bird species are doing there. Over three years, we did lots of field surveys during different times of the year. We used methods like point counts, transect walks, and habitat checks. In total, we found 184 bird species resident birds that live there all year and migrating ones that visit. We even spotted some species that need special attention. This shows how important the lake is for both local birds and those just flying between. When we looked closely at the numbers through the seasons, we found some big changes in how many birds there were. Winter was especially busy, with a lot of different kinds showing up and the migratory birds arriving. The study also identified key threats to avian biodiversity in the lake, such as habitat degradation, water pollution, and human disturbances. Based on these findings, the study recommends urgent conservation measures, including habitat restoration, pollution control, and the implementation of strict regulations to minimize human impact. This survey underscores the importance of Nanjarayan Lake as a vital bird habitat and calls for enhanced conservation efforts to protect its rich avian diversity. The findings provide valuable baseline data for future ecological studies and contribute to the broader understanding of lake ecosystems in Tamil Nadu.

Industrial and Pharmaceutical Applications of Microbial Diversity of Hypersaline Ecology from Lonar Soda Crater.

The unidentified geochemical and physiochemical characteristics of Soda Lakes across the globe make it a novel reservoir and bring attention to scientific civic for its conceivable industrial and pharmaceutical applications. In India, in the Maharashtra state, Lonar Lake is a naturally created Soda Lake by a meteorite impact. Phylogenetic data from this lake explored a diverse array of microorganisms like haloalkaliphilic bacteria and Archaea. Previously reported studies postulated the major microbial communities present in this lake ecosystem are Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria. Furthermore, it also contains Bacteroidetes, Nitrospirae, and Verrucomicrobia. This lake is also rich in phytoplankton, with the predominant presence of the Spirulina plantensis. Unique microbial strains from Lonar Lake ecosystems have fascinated consideration as a source of biological molecules with medicinal, industrial, and biotechnological potential. Recent literature revealed the isolation of antibioticproducing bacteria and alkaline proteases-producing alkaliphilic bacterium, as well as novel species of rare methylotrophs, other bacterial strains involved in producing vital enzymes, and unique actinomycetes are also reported. It indicates that the novel bacterial assemblage not reached hitherto may exist in this modified and unique ecology. This comprehensive review provides information about microbial diversity and its industrial and pharmaceutical interests that exist in Lonar Lake, which could be the future source of bioactive enzymes, biosurfactants, and biofuel and also useful in bioremediation. Furthermore, the novel species of microorganisms isolated from Lonar Lake have applications in the biosynthesis of medicines like antibiotics, antivirals, antifungals, anti-inflammatory agents, and precursors for synthesising valuable products. Data consolidated in the present review will cater to the needs of emerging industrial sectors for their commercial and therapeutic applications.

The future of algal blooms in lakes globally is in our hands

Lakes are fundamental to society and nature, yet they are currently exposed to excessive nutrients and climate change, resulting in algal blooms. In the future, this may change, but how and where still needs more scientific attention. Here, we explore future trends in algal blooms in lakes globally for >3500 ‘representative lakes’ for the year 2050, considering the attribution of both nutrient and climate factors. We soft-coupled a process-based lake ecosystem model (PCLake+) with a watershed nutrient model (MARINA-Multi) to assess trends in algal blooms in terms of the Trophic State Index for chlorophyll-a (TSI-Chla). Globally between 2010 and 2050, we show a rising trend in algal blooms under fossil-fuelled development (TSI-Chla increase in 91 % of lakes) and a declining trend under sustainable development (TSI-Chla decrease in 63 % of lakes). These changes are significantly attributed to nutrients. While not always significant, climate change attributions point to being unfavourable for lakes in 2050, exacerbating lake water quality. Our study stresses prioritising responsible nutrient and climate management on policy agendas. This implies that the future of algal blooms in lakes is in our hands.

An Invasive Predator Substantially Alters Energy Flux Without Changing Food Web Functional State or Stability

ABSTRACTUnderstanding how invasive species affect the stability and function of ecosystems is critical for conservation. Here, we quantified the effect of an actively suppressed invasive species on the Yellowstone Lake ecosystem using a food web energetics approach. We compared energy flux, functional state, and stability of four food web states: a pre‐invasion network and three post‐invasion networks undergoing active invasive species suppression, namely, initial invasion, expansion, and decline. Invasion caused ≥ 25% change (±) in energy flux for most consumers, and total flux increased twofold post‐invasion. Flux to the species of conservation concern, Yellowstone cutthroat trout (Oncorhynchus virginalis bouvieri), was 2.8 times less post‐invasion versus pre‐invasion, whereas invasive lake trout (Salvelinus namaycush) flux was up to 17.3 times higher compared to the initial invasion network. The dominant functional state and food web stability did not change post‐invasion, likely due to introduction of a generalist predator and the stabilizing effect of suppression. Lake trout invasion in Yellowstone Lake caused large changes to energy flux, shifting dominant fluxes away from the species of conservation concern, despite not changing functional state or stability. We demonstrate that changes in energy flux may signal invasions in ecosystems, but functional state or stability may not necessarily reflect the magnitude of invasion influences. For invaded fish communities, a better understanding of how the invasive species control the food web beyond just the direct influence on prey can be achieved by investigating energy flux, functional state, and food web stability. Furthermore, evaluating the effect of suppression beyond the invasive species can demonstrate the far‐reaching value of suppression management actions for conservation.

Scale-dependent population drivers inform avian management in a declining saline lake ecosystem.

Shrinking saline lakes provide irreplaceable habitat for waterbird species globally. Disentangling the effects of wetland habitat loss from other drivers of waterbird population dynamics is critical for protecting these species in the face of unprecedented changes to saline lake ecosystems, ideally through decision-making frameworks that identify effective management options and their potential outcomes. Here, we develop a framework to assess the effects of hypothesized population drivers and identify potential future outcomes of plausible management scenarios on a saline lake-reliant waterbird species. We use 36 years of monitoring data to quantify the effects of environmental conditions on the population size of a regionally important breeding colony of American white pelicans (Pelecanus erythrorhynchos) at Great Salt Lake, Utah, US, then forecast colony abundance under various management scenarios. We found that low lake levels, which allow terrestrial predators access to the colony, are probable drivers of recent colony declines. Without local management efforts, we predicted colony abundance could likely decline approximately 37.3% by 2040, although recent colony observations suggest population declines may be more extreme than predicted. Results from our population projection scenarios suggested that proactive approaches to preventing predator colony access and reversing saline lake declines are crucial for the persistence of the Great Salt Lake pelican colony. Increasing wetland habitat and preventing predator access to the colony together provided the most effective protection, increasing abundance 145.4% above projections where no management actions are taken, according to our population projection scenarios. Given the importance of water levels to the persistence of island-nesting colonial species, proactive approaches to reversing saline lake declines could likely benefit pelicans as well as other avian species reliant on these unique ecosystems.

Application of Synchronous Evaluation-Diagnosis Model with Quantitative Stressor-Response Analysis (SED-QSR) to Urban Lake Ecological Status: A Proposed Multiple-Level System.

Ecological integrity assessment and degradation diagnosis are used globally to evaluate the health of water bodies and pinpoint critical stressors. However, current studies mainly focus on separate evaluation or diagnosis, leading to an inadequate exploration of the relationship between stressors and responses. Here, based on multiple data sets in an urban lake system, a synchronous evaluation-diagnosis model with quantitative stressor-response analysis was advanced, aiming to improve the accuracy of evaluation and diagnosis. The weights for key physicochemical stressors were quantitatively determined in the sequence of NDAVIadj > CODMn > TP > NH4+-N by the combination of generalized additive model and structural equation modeling, clarifying the most significant effects of aquatic vegetation on the degradation of fish assemblages. Then, sensitive biological metrics were screened by considering the distinct contributions of four key stressors to alleviate the possible deviation caused by common methods. Finally, ecological integrity was evaluated by summing the key physicochemical stressors and sensitive biological metrics according to the model-deduced weights instead of empirical weights. Our system's diagnosis and evaluation results achieved an accuracy of over 80% when predicting anthropogenic stress and biological status, which highlights the great potential of our multiple-level system for ecosystem management.

Inactivation effect and mechanism of Pediastrum by in-liquid pulsed discharge plasma

The issue of eutrophication in river and lake ecosystems is escalating, resulting in harmful algal blooms that adversely impact the aquatic environment. Thus, it is crucial to develop new technology that can effectively inactivate algae without causing secondary pollution to the water body. This work uses in-liquid pulsed discharge plasma technique to inactivate Pediastrum. The research investigates variations in inactivation ratios, chlorophyll-a concentrations, and the inactivation mechanisms under different discharge conditions. The results indicate that the optimal inactivation effect is achieved at a peak voltage of 30 kV, an electrode spacing of 7 mm, and a discharge duration of 20 min, resulting in a 90 % inactivation ratio and a reduction in chlorophyll-a concentration from 1.31 mg/L to 0.63 mg/L (on the fourth day of re-culturing). The discharge process generates strong shock waves, ultraviolet lights, and significant amounts of oxidizing agents, such as· O, H2O2, O3, leading to cell damage, cell wall disruption, and enzyme activity reduction, thereby achieving effective inactivation.

Analysis of bacterial community structure, functional variation, and assembly mechanisms in multi-media habitats of lakes during the frozen period

Ice, water, and sediment represent three interconnected habitats in lake ecosystems, and bacteria are crucial for maintaining ecosystem equilibrium and elemental cycling across these habitats. However, the differential characteristics and driving mechanisms of bacterial community structures in the ice, water, and sediments of seasonally frozen lakes remain unclear. In this study, high-throughput sequencing technology was used to analyze and compare the structure, function, network characteristics, and assembly mechanisms of bacterial communities in the ice, water, and sediment of Wuliangsuhai, a typical cold region in Inner Mongolia. The results showed that the bacterial communities in the ice and water phases had similar diversity and composition, with Proteobacteria, Bacteroidota, Actinobacteria, Campilobacterota, and Cyanobacteria as dominant phyla. The bacterial communities in sediments displayed significant differences from ice and water, with Chloroflexi, Proteobacteria, Firmicutes, Desulfobacterota, and Acidobacteriota being the dominant phyla. Notably, the bacterial communities in water exhibited higher spatial variability in their distribution than those in ice and sediment. This study also revealed that during the frozen period, the bacterial community species in the ice, water, and sediment media were dominated by cooperative relationships. Community assembly was primarily influenced by stochastic processes, with dispersal limitation and drift identified as the two most significant factors within this process. However, heterogeneous selection also played a significant role in the community composition. Furthermore, functions related to nitrogen, phosphorus, sulfur, carbon, and hydrogen cycling vary among bacterial communities in ice, water, and sediment. These findings elucidate the intrinsic mechanisms driving variability in bacterial community structure and changes in water quality across different media phases (ice, water, and sediment) in cold-zone lakes during the freezing period, offering new insights for water environmental protection and ecological restoration efforts in such environments.

Status and Migration Activity of Lead, Cobalt and Nickel in Water and in Bottom Sediments of Lake Markakol, Kazakhstan

Lake Markakol is located in a metal-rich mountain area of Kazakhstan. Metal input into the lake water and in the bottom sediments can be expected. Lead, cobalt and nickel monitoring in both near-surface and deep-water layers and in bottom sediments was carried out using flame atomic absorption spectrometric analyses. Lead contamination of surface water ranging from 2.6 to 6.8 µg/L occurs in all water samples with the exception of the surface water layer. In the deep-water section concentrations reach up to 13.0–16.2 µg/L. Cobalt concentrations range from 36.8 to 67.5 µg/L in the surface layer and from 25.5 to 69.2 µg/L in the deep-water layer. High values of nickel were found in the surface and bottom layers of the water, ranging from 13.5 to 49.0 and 17.2 to 49.0 µg/L, respectively. High concentrations of lead, cobalt and nickel were identified in all samples of the bottom sediments. The lead content in bottom sediments reaches 11.3, cobalt reaches 10.3–18.0 and nickel reaches 15.0 mg kg−1. The results and their assessment can serve as a basis for future monitoring and measures to reduce pollution, restore the lake ecosystem and ensure the safety of fishery products for humans.

Morphological responses of ostracods to heavy metal contamination: freshwater ostracods as bioindicators of pollution in Ichkeul Lake and rivers ecosystem, northern Tunisia

Morphological responses of ostracods to heavy metal contamination: freshwater ostracods as bioindicators of pollution in Ichkeul Lake and rivers ecosystem, northern Tunisia

Lake Superior fish community and fisheries, 2001–2022: An era of stability

Lake Superior is the least anthropogenically impacted of the Laurentian Great Lakes ecosystems, yet dramatic changes to the fish community are evident. Previous published works chronicled those changes and the efforts to rehabilitate the fish community through the year 2000. Here, we review through the year 2022, where post-rehabilitation stability was driven by lean lake trout (Salvelinus namaycush namaycush) as the most abundant piscivore in nearshore waters, siscowet lake trout (Salvelinus namaycush siscowet) as the most abundant piscivore in offshore waters, and a healthy, intact assemblage of native prey species, which created ecological redundancies and helped stabilize the food web. Stocking of non-native salmonines was reduced 74%, and populations of Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) were maintained through natural reproduction. Despite reduced stocking, yield from recreational fisheries was stable. Likewise, developments in population modeling led to evaluations and refinement of management strategies that helped create stability for lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) fisheries. With lake trout rehabilitation achieved, focus shifted toward rehabilitation of native brook trout (Salvelinus fontinalis), lake sturgeon (Acipenser fulvescens), and walleye (Sander vitreus). Despite continued control efforts, sea lamprey (Petromyzon marinus) abundance increased considerably, and estimates of fish killed by lampreys averaged 2.65 million kg annually. Environmental changes have benefited sea lampreys and fostered thermal habitats more suitable to non-native organisms, posing new challenges for managers and researchers. Nevertheless, the post-rehabilitation stability in the contemporary fish community will help provide resilience to future perturbations in the ecosystem.

Declines and shifts in morphological diversity of ciscoes (Coregonus spp.) in lakes Huron and Michigan, 1917–2019

Ciscoes ( Coregonus spp .) were historically abundant and ecologically important in Laurentian Great Lakes ecosystems. Despite well-documented declines in their abundance and taxonomic diversity, declines in morphological diversity remain understudied. This knowledge gap is especially pertinent for lakes Michigan and Huron, which have each lost six of eight historical species. Improved understanding of historical and contemporary morphological diversity of Great Lakes ciscoes can inform ongoing restoration efforts and further elucidate the factors that contributed to declines. Our goal was to characterize shifts in morphological diversity of ciscoes in lakes Michigan and Huron over a century (1917–2019). We analyzed size-corrected morphometric and meristic measurements from three periods: Early (1917–1923), Middle (1950–1972), and Contemporary (2015–2019). We then identified morphologically distinct clusters while remaining agnostic to species identifications. We found that morphological diversity and the number of distinct clusters declined over time. We then leveraged species identifications to highlight key species losses and examine morphological shifts among extant species. Our findings provide insights into the historical and contemporary morphological diversity of ciscoes and will inform restoration efforts.

Evidence of Climate Change and the Conservation Needed to Halt the Further Deterioration of Small Glacial Lakes

Although somewhat debated, it is generally agreed in Europe that small water bodies comprise lentic ecosystems that are shallow (less than 20 m) and have a surface area of a few hectares (less than 10 ha). In Albania, 84 glacial lakes constitute a substantial portion of the aquatic ecosystems that sustain high levels of biodiversity, metabolic rates, and functionality. This paper discusses the integration of ecological sustainability into ecosystem services (i.e., cultural, regulatory, and sustaining services) and the national ecological networks of protected sites. This integration is particularly important in light of recent advancements regarding European integration. It is also important due to the catchment continuum, which addresses biodiversity values and gradients that, in this work, are considered using rotifer communities and aquatic plant species. The main causes of the stressors on small ecosystems are inappropriate land use, water pollution, altered habitats, non-native species introduction, resource mismanagement in basins, inadequate planning, and a lack of sector integration. The glacial lakes reflect climate change elements through: an increased number of dried glacial lakes, so only 84 remain functioning; the water level is slowly being reduced; the oscillation of the water level is steadily increasing; and the eutrophication process is rapidly advancing.

Research on the Relationship between Eukaryotic Phytoplankton Community Structure and Key Physiochemical Properties of Water in the Western Half of the Chaohu Lake Using High-Throughput Sequencing

Eukaryotic phytoplankton play a major role in the circulation of material and energy in a lake’s ecosystem. The acquisition of information on the eukaryotic phytoplankton community is extremely significant for handling and regulating the ecosystems of lakes. In this study, samples were collected from the western half of Chaohu Lake in the summer and winter periods. Analyses revealed that the eukaryotic phytoplankton in this region comprised 70 genera, 34 orders, and 7 phyla. There were 61 genera, 29 orders, and 7 phyla in summer, and 25 genera, 14 orders, and 5 phyla in winter. The dominant genus was Chlamydomonas of Chlorophyta in summer. In contrast, the dominant genus was Mychonastes of Chlorophyta in winter. The diversity index analysis revealed that the eukaryotic phytoplankton community exhibited greater fluctuation in the summer than in the winter. Moreover, analysis of the physiochemical properties of the water samples showed considerable spatial and temporal differences in the water quality. This paper focusses primarily on analysing the influence of the physiochemical properties of water on the eukaryotic phytoplankton community. In particular, the effects of the major physicochemical properties of water on the community evolution of eukaryotic phytoplankton classes were evaluated using the redundancy analysis method. The findings demonstrated that total phosphorus (TP), PO4−-P, NH4+-N, and total nitrogen (TN) were the primary influencing factors in summer, whereas NO3−-N, DO, and water temperature (WT) were the major influencing factors in winter. Subsequently, the Mantel test revealed that the phylum level of the eukaryotic phytoplankton community was significantly correlated with WT, DO, NH4+-N, TN, TP, and Chlorophyll a. Variance partitioning analysis indicated that seasonal factors accounted for a large proportion of the variation in the eukaryotic phytoplankton community, reaching 48.4%. Subsequently, co-occurrence network analysis demonstrated that most families of eukaryotic phytoplankton were facilitated mutually, with the proportion of promotion being 94.1%. This study provides insight into the crucial factors that influence the phytoplankton communities and a reasonable control direction for the positive evolution of the eukaryotic phytoplankton community in the western half of Chaohu Lake.

Rotifer functionality as a potentially useful indicator of lake browning

Lake browning is considered a severe water quality problem in lake ecosystems, but it has received considerably less attention in water protection than eutrophication. Current metrics used in lake surveillance monitoring programmes, including the European Union’s Water Framework Directive, do not reflect browning sufficiently. The aims of the study were to explore the potential role of the functionality of rotifers as browning indicators and to improve understanding of the environmental parameters driving the functionality and diversity of rotifers. Seasonal data on rotifer communities and water quality from seven lakes with differing water colour and trophic conditions were analysed. The feeding guilds of rotifers enabled differentiation between lakes in terms of their ecological conditions, and, in particular, eutrophic and brown-water lakes were clearly distinguished from other lakes. The guild ratio of rotifers was positively affected by water colour, but inversely related to total phosphorus concentration. Our results suggest that zooplankton functionality provides a potential tool to assess ecosystem dynamics, particularly when assessing lake browning. Thus, our results suggest that application of the guild ratio of rotifers is a promising method to estimate the general browning status of lakes and may complement the metrics used in Water Framework Directive.

Satellite-ground synchronous in-situ dataset of water optical parameters and surface temperature for typical lakes in China

Remote sensing technology has the potential to enhance the lake’s large-scale and long-term dynamic monitoring capabilities significantly. High-quality in-situ datasets are essential for improving the accuracy and reliability of remote sensing retrieval of lake ecosystems. This dataset provides satellite-ground synchronized in-situ data on water multi-parameters for typical lakes in China spanning the period between 2020 and 2023. It includes quality-checked water optical parameters (remote sensing reflectance (Rrs), chlorophyll-a (Chl-a), total suspended matter (TSM) and Secchi disk depth (SDD)), and water surface temperature (WST) data. It encompasses 586 sampling points across 18 lakes. The dataset exhibits two significant highlights: Firstly, synchronous observations from multiple satellites are coordinated during the data collection effectively supporting the retrieval and validation of water remote sensing products. Secondly, it encompasses diverse data types, collecting synchronous measurements of Rrs and various parameters. This dataset will continuously update, substantially enhancing regional and global lake monitoring capabilities through satellite remote sensing data.

Effects of the main media of wind and water on the biodiversity pattern of grassland and its driving mechanism in Poyang Lake

AbstractAs important media for species diffusion, water and wind are two important factors for grassland biodiversity conservation in lake areas. Exploring their driving mechanism on grassland biodiversity is crucial for maintaining the lake ecosystem's equilibrium. Our study utilizes the data of wind velocity and water level, which are significant performance factors for wind and water respectively in Poyang Lake from 2000 to 2020 to reveal their interannual time‐series fluctuation characteristics and their influence mechanism on the grassland biodiversity pattern. Landscape pattern indices and biodiversity indicators, such as the number of patches (NP), patch density (PD), landscape spreading index (CI), landscape fragmentation index (LSD), landscape aggregation index (AI), Simpson diversity index (MSIDI) and Simpson evenness index (MSIEI) were analysed, trend analysis, redundancy analysis and structural equation modelling were applied in this study. The main results were: (1) From 2000 to 2020, Poyang Lake's wind velocity decreased gradually, and the water level first decreased and then rose. NP in Poyang Lake fluctuated substantially, LSD fluctuated frequently and obvious temporal heterogeneity existed. (2) CI and AI increased from low to high value, facilitating species dispersal and migration. The dominant species with high aggregation gradually established stronger connectivity. Moderate spreading degree and aggregation degree maintained high biodiversity and evenness, whereas excessive spreading degree and aggregation degree led to homogenization of species, decrease in biodiversity, reduction in species evenness, and increase in dominance. (3) As the landscape transformed from having no obvious dominant species to being dominated by several dominant species, MSIEI and landscape dominance changed from high to low and low to high respectively. Moreover, the biodiversity shifted from high to low, and species distribution in the landscape shifted from balanced to unbalanced. (4) The effect of water level on PD, AI, LSD, MSIDI and MSIET was significantly higher than that of wind velocity. LSD was mainly regulated by the minimum wind velocity affecting the maximum and average water levels. MSIDI and MSIET were primarily governed by the minimum wind velocity affecting the minimum water level. The minimum water level decreased as the minimum wind velocity increased, and MSIDI and MSIET weakened as the minimum water level decreased.

Dual impacts of hydrology and damming on eutrophication: Comparison of two Ramsar wetlands in the middle Yangtze floodplain

Dam construction for social-economic benefits has raised substantial biological and ecological concerns. However, contrasting findings have been reported regarding the role of hydrological modification in floodplain lake ecosystems. Here, we evaluated the influence of hydrology and dam construction on the eutrophication of floodplain lakes over the last 200 years by studying Zn/Al (an indicator of industrial activities), nutrient influxes (total phosphorus, TP), cyanobacteria production (canthaxanthin) and aquatic invertebrate dynamics (chironomids) in 210Pb dated sediment cores from two Ramsar Wetlands of International Importance in the middle Yangtze floodplain, one dammed (Wanghu) and the other freely connected (Poyang) with the Yangtze River. The results show that Wanghu Lake transitioned to a macrophyte-dominated clear water state (as indicated by the increases in pigment derived ultraviolet radiation index and dominance of macrophyte-related chironomid taxa) after local dam construction when anthropogenic nutrient loadings were relatively low. With increases in nutrient loadings, phytoplankton increased in both lakes, but water clarity declined and macrophyte-related chironomids decreased only in the lake which was locally dammed. Our study reveals that local damming facilitates the response of floodplain lake ecosystems to eutrophication and decouples it from the effects of hydrological variability. This study highlights the potential influence of hydrology and damming on the eutrophication of floodplain lakes by influencing water clarity and macrophyte coverage, implying that evaluating the role of local dam construction on ecosystem states should be based on knowledge of nutrient conditions in floodplain lakes.

Nutrient removal in floating and vertical flow constructed wetlands using aluminium dross: An innovative approach to mitigate eutrophication

On global scale, eutrophication is one of the most prevalent environmental threats to water quality, primarily caused by elevated concentration of nutrients in wastewater. This study utilizes aluminum dross (AD), an industrial waste, to create a value-added material by improving its operational feasibility and application for removing phosphate and ammonium from water. The operational challenges of AD such as its powdered nature and effective operation under only extreme pH conditions were addressed by immobilizing in calcium alginate to form calcium alginate aluminium dross (Ca-Alg-Al dross) beads. These Ca-Alg-Al dross beads were further tested for phosphate and ammonium removal from natural wastewater in two different aqueous environment systems: (i) vertical flow constructed wetlands (VF-CWs) followed by Ca-Alg-Al dross beads fixed bed system and (ii) Ca-Alg-Al dross beads mounted floating constructed wetlands (FCW) for remediating polluted lentic ecosystems. Our results show maximum phosphate and ammonium removal of 85 ± 0.41 % and 93.44 %, respectively, in VF-CWs followed by Ca-Alg-Al dross beads fixed bed system. The Ca-Alg-Al dross beads mounted FCW system achieved maximum phosphate removal of 79.18 ± 8.56 % and ammonium removal of 65.45 ± 21.04 %. Furthermore, the treated water from the FCW system was assessed for its potential to inhibit algal growth by artificially inoculating treated water with natural algae to simulate eutrophic conditions. Interestingly, treated water from the FCW system was found capable of arresting the algal growth. Besides, scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and Fourier transform infrared (FTIR) spectroscopy confirmed the functional groups and surface properties and probable participation of multiple mechanisms including ion exchange, electrostatic attraction, and ligand complexation for phosphate and ammonium removal. Overall, these results offer a promising way to utilize AD for high-end applications in wastewater treatment.

Does polymixis complicate prediction of high‐frequency dissolved oxygen in lakes and reservoirs?

AbstractAs lake and reservoir ecosystems transition across major environmental regimes (e.g., mixing regime) resulting from anthropogenic change, setting predictive expectations is imperative. We tested the hypothesis that (dissolved) oxygen is more predictable in monomictic reservoirs that thermally stratify throughout the summer (warm) season compared to polymictic reservoirs that stratify intermittently. Using two‐hourly vertical profiles of oxygen, we compared daily‐aggregated errors of oxygen predictions from random forests across and within two monomictic and two polymictic reservoirs in the south‐central (subtropical) USA. Although one monomictic reservoir was typically more predictable than the polymictic reservoirs, the hypereutrophic, small monomictic reservoir had less predictable oxygen patterns potentially related to rapid oxygen cycling and intrusions of oxygenated waters in the hypolimnion without mixing. Daily mixing did not relate strongly to model errors. Water temperature, depth, and wind were the most important predictors, but were not clearly related to season or mixing. Lastly, we compared multiple model types (regression, neural network, and process‐based) in one polymictic reservoir to test how our interpretations of oxygen predictability were sensitive to model type, finding that the models generally agreed; however, the process‐based model poorly predicted oxygen in the middle of the vertical profiles (5 m) where most models performed poorly due to a temporally unstable, vacillating metalimnion. Our results suggest predicting reservoir oxygen dynamics may be easier in stratified reservoirs, but eutrophication and complex hydrodynamics may cause forecasting surprises especially for those who use or manage water resources in mono‐ or dimictic reservoirs.