Lake Catchment Area Research Articles

Inventory of Pollution Sources for The Lakes of Universiti Tun Hussein Onn Malaysia

Eutrophication affects freshwater systems worldwide. Eutrophication can occur naturally, but man-made causes are also common. Human activities that release phosphorus and nitrogen lead to anthropogenic eutrophication, which increases organic matter production. Lake eutrophication affects surface waters all over the world. Water pollution can be assessed regarding point sources (PS) and non-point sources (NPS). PS is the intentional or unintentional release of pollutants from industrial and wastewater facilities into waterways. Agriculture, urban development, and natural processes in the lake's catchment area can cause NPS pollution. NPS pollution has many causes, including precipitation, airborne deposition, infiltration, drainage, and fluctuations in water flow in the catchment. The pollution inventory was conducted in UTHM lakes such as Tasik Kemajuan, Tasik Teknologi (FKAAB), Tasik Teknologi (FPTV), and Tasik Pembangunan. The PS and NPS in the study area were assessed through an on-site investigation. The UTHM water discharge plan is being analyzed to determine the inflow sources into the lake. The PS pollutant inventory revealed that the cafeteria wastewater, business buildings, and faculty drainage systems pollute all lakes. Tasik Teknologi (FPTV) identified runoff from palm oil plantations as a source of pollutants that can increase the nutrient content of the lake. Leaves, grass clippings, and other garden waste were in the water in all the lakes analysed. The Tasik Kemajuan, the Tasik Teknologi (FKAAB), and the Tasik Teknologi (FPTV) received water discharges from other lakes transporting pollutants. The assessment of pollutant sources revealed that most NPS originate from surface runoff. Road runoff contains several pollutants. Stormwater runoff or surface runoff can carry these pollutants from roads into waterways. Stormwater washes fertilizers into storm drains and lakes. To summarise, all pollutant sources that contributed to the eutrophication of the Tasik Kemajuan, Tasik Teknologi (FKAAB), Tasik Teknologi (FPTV), and Tasik Pembangunan were identified through a pollutant source inventory.

Assessing Two Decades of Land Use/Land Cover Changes in the Uluabat Lake Ramsar Site using Multi-Temporal Satellite Imagery

The Ramsar Convention on Wetlands designates over 2,000 sites of international importance, providing crucial habitats for diverse species. Uluabat Lake, faces anthropogenic pressures such as urbanization, agriculture, and industrialization, affecting its ecological integrity. Using multi-temporal Landsat 7 and Landsat 9 satellite images from 2002 and 2022, along with 2019 management plans, we assessed land use/land cover (LULC) changes in the lake's catchment area. Data were pre-processed with ENVI and stored in ERDAS Imagine. We employed pixel-based image analysis with maximum likelihood classification (MLC) to generate LULC maps and evaluated classification accuracy using ground truth data and the kappa coefficient. Our findings revealed a 15.8% reduction in lake area, from 136.1 km² in 2002 to 114.5 km² in 2022, primarily due to sediment transport from surrounding agricultural land and tributary streams. Urban-agricultural and reed-swamp areas increased by 74.7% and 59.6%, respectively, while shrubs and forests declined by 35.64%, largely from reed conversion to agriculture in the Mustafakemalpaşa River delta. Overall classification accuracy ranged from 88.2% to 91% with a kappa coefficient of 0.81 to 0.82. These transformations highlight the increase in reed and swamp areas and the decrease in lake area, emphasizing the need for effective conservation and management practices.

STUDYING THE EUTROPHICATION OF LAKES IN VOLYN POLISSYA (ON THE EXAMPLE OF LAKE ZASVITSKE)

Many diverse lakes are a natural phenomenon of Volyn Polissya. They are of great ecological, recreational and economic importance. As a result of intensive economic activity, pollution and other anthropogenic factors, many lakes are subject to eutrophication. Excessive enrichment of water bodies with nutrients causes the rapid development of algae, deterioration of water quality and disruption of ecological balance. Global climate change has also had a significant impact on this process in recent years. Lake Zasvitske was chosen for the study. It is located in the north-west of Rivne Oblast, in the Varash district, south of the village of Mlyn and north-west of Lake Nobel. It is part of the Nobel National Nature Park. The area of the lake is 22 hectares. Is 620 m long, 350 m wide, has a maximum depth of 16 m, an average depth of 12.5 m, a coastline of 1.75 km and a capacity more than 5 million m3. The lake is fed primarily by atmospheric precipitation and groundwater from. The ecological condition of the watershed is favorable, there are no potentially dangerous objects, the lake is surrounded by pine forests to the north, east and south, and there are equipped small beaches on the western and northwestern sides. The lake water is quite clean. Concentrations of pollutants are exceeded only by the indicator of biological oxygen consumption by 28% and zinc content by 3.1 times. The NDVI and NDAI indices were used to assess the eutrophication of the lake. NDVI (Normalized Difference Vegetation Index) is a quantitative indicator of photosynthetically active biomass most often used to assess eutrophication processes in water bodies. The value of the index varies from -1 to 1. Negative values of the NDVI index indicate the presence of water in the form of clouds and snow; values close to zero (-0.1 to 0.1) correspond to areas with no vegetation cover. Values from 0.2 to 0.9 indicate active vegetation (including in water bodies). NDAI (Normalized Difference Algae Index) is used to diagnose the process of algae overgrowth in a water body and determine the stage of this process. NDVI values increase with the beginning of the transition of the average daily temperature through 0°C, with maximum values reached in late July - early August. Subsequently, the values decrease until the onset of frost. For example, on April 1, 2022. NDVI acquires small positive values up to 0.1. By mid-May, the index values rise to 0.1-0.2. In the eastern part of the lake, where hygrophytes are found, it increases to 0.3. By the end of the month, the NDVI values for most of the reservoir drop again to 0. At the end of June, the index values increase to 0.1 and decrease again. In the first decade of July, the water is cleared of algae. The index acquires negative values (up to -1), which corresponds to clean water. In August-September, the index values vary in the range (-0.1; -0.5). The NDAI index allows us to better trace the seasonality of vegetation processes in the lake. In early April, the development of vegetation processes begins from the belt of semi-flooded hygrophytes along the shores of the reservoir, covering the island rise in the north of the lake. In summer, the intensity of vegetation processes increases, reaching a peak in September. Subsequently, the vegetation dies off and the process repeats in a new vegetation cycle. Keywords: lake, lake catchment area, limnosystem, geo-ecological state of the catchment area, lake eutrophication, measures to prevent and reduce lake eutrophication.

Biometric indices of eight fish species from the catchment area of Kaptai lake, Bangladesh

Biometric indices viz. i) Length-weight relationships (LWRs), ii) form factor (a0.3) and iii) condition factors (relative KR and Fulton's KF) were presented for 8 fish species collected from Kaptai lake at five sampling points including Rangamati Sadar, Barkal, Naniarchar, Langadu and Kaptai upazila. A total of 3204 individuals belonging to 3 families were measured and weighed between August 2020 to April 2021 by the catch assessment survey with different types of fishing gear (seine net, current net, gill net and lift net). Calculations were made for the parameters a and b of the eq. W = aTLb. The analysis of covariance (ANCOVA) revealed significant differences between stations in LWRs for all species (P < 0.01). The parameter b of the LWRs ranged from 2.34 (Parambassis lala) to 3.34 (Ailia coila) with a mean value of 2.98 (SE: 0.11) and 50% of its fall within the interval 2.9–3.2. Results showed that 3 species showed positive allometric growth (Gonialosa manminna, Ailia coila, and Eutropiichthys vacha), 3 showed negative allometric growth (Gudusia chapra, Chanda baculis, and Parambassis lala), and 2 exhibited isometric growth (Corica soborna, Chanda nama). The findings further indicated that the LWRs of 8 species were highly correlated (r2 > 0.90, P < 0.001). The a3.0 value estimated for eight species varied from 0.0043 to 0.0114. The KR value ranged from 0.26 to 4.97 and KF value ranged from 0.17 to 2.89; showed significant differences of KR and KF between stations for eight species. As per FishBase, a new record for the maximum size of C. soborna and C. baculis was documented as 7.1 cm and 8.1 cm, respectively. This research is the first to provide information on biometric indices for six species (C. soborna, C. nama, C. baculis, P. lala, A. coila and E. vacha) in Kaptai Lake, which may aid in management and conservation throughout the country, including their geographical distribution.

Microplastic pollution in high-altitude Nainital lake, Uttarakhand, India

Microplastics (MPs) contamination has been reported in all environmental compartments, but very limited information is available at higher-altitude lakes. Nainital Lake, located at a high altitude in the Indian Himalayas, has various ecosystem services and is the major source of water for Nainital town, but the MP abundance is still unknown. This study presents the first evidence of the abundance and distribution of MP in Nainital Lake. Surface water and sediment samples were analysed from 16 different sites in and around the catchment area of Nainital Lake. The MP were observed in all the samples, and their abundance in surface water was 8.6–56.0 particles L−1 in the lake and 2.4–88.0 particles L−1 in hotspot sites. In the surface sediment, MP abundance ranged from 0.4–10.6 particles g−1, while in the hotspot sediment, the mean abundance was 0.6 ± 0.5 particles g−1. Fibers were the dominant MP, while 0.02–1 mm were the predominant size of MP particles. The results of chemical characterization showed the presence of six polymers, among which high-density polyethylene was the most abundant. The Polymer Hazard Index assessment classified the identified polymers as low-to high-risk categories, with a higher abundance of low- (polypropylene) and medium- (polyethylene)-risk polymers. Tourist activities and run-off catchments can be considered the major sources of MP, which can affect the ecosystem. Minimal concentrations of MP were observed in the tube well and drinking water, which depicts the direct risks to humans and, thus, the need for remedial measures to prevent MP contamination in drinking water. This study improves the knowledge of MP contamination in the higher-altitude freshwater lake, which can be the major pathway for the transport of MP to the rivers, and also emphasizes the need for waste management in Nainital town.

Spatiotemporal ecological risk evaluation and source identification of heavy metals and nutrients in the water and lake surface sediment in a protected catchment area of a volcanic lake.

Indonesia has numerous lakes; however, research on the spatiotemporal sediment quality and source identification in lakes remains limited. The overaccumulation of heavy metals and nutrients in lakes severely threatens aquatic ecosystems. This study aims to identify potential sources of metallic deposits (Cu, Pb, Cr, Fe, Al, and Cd) and nutrients (TN and TP) in lake-surface sediment, utilizing enrichment factors (EF), geoaccumulation indices (Igeo), potential ecological risk indices (Er), and risk indices (RI). Multivariate statistical analyses, including principal component analysis (PCA) and Pearson's correlation analysis, were conducted to pinpoint pollution sources linked to land use. Eight sampling sites for surface sediment and water were examined in both wet and dry seasons at Menjer Lake, chosen for its diverse applications in tourism, hydropower, floating net cages, and extensive agriculture in its catchment. Correlation and PCA results indicated that Pb, Fe, and Al mainly originate from tourism, while Al, Fe, TN, and TP are associated with agriculture. The highest average loading from land use was observed in agriculture (> 0.8), floating net cages (> 0.76), and tourism (> 0.68). Furthermore, the highest loading from nutrients and all metals were TP (> 0.71) and all metals (> 0.35), respectively. Ecological risk assessment revealed low to moderately polluted EFs and Igeo in the dry season. However, Menjer Lake's Er and RI for heavy metals were generally classified as unpolluted.

Assessment of heavy metal contamination and sediment characteristics in Ozomu lake, southern Nigeria: Implications for environmental health

This study investigates heavy metal concentrations and surface sediment characteristics in the Ozomu Lake, located in southern region of Nigeria. Sediment samples were systematically collected across three stations, over six months, spanning from March to August. This period encompasses the transition from the late dry season to the early wet season, offering valuable insights into the seasonal variations of heavy metal distribution and sediment properties. The concentrations of heavy metals in the sediment were determined using standard methods, along with the analysis of particle size distribution and organic content (% organic carbon and % organic matter). Essential findings reveal significant values. Iron (Fe) averaged 1194.86 mg/kg, zinc (Zn) 30.71 mg/kg, copper (Cu) 14.80 mg/kg, manganese (Mn) 17.43 mg/kg, lead (Pb) 1.17 mg/kg, and cadmium (Cd) 0.18 mg/kg. Enrichment factor (EF) assessments indicate notable enrichment in Fe, Zn, Cu, Mn, and Cd. Key sediment properties include total organic carbon (%TOC) at 4.46%, total organic matter (%TOM) at 7.72%, and particle size distribution with clay at 8.99%, silt at 6.24%, and sand at 84.77%. Principal component analysis (PCA) uncovers intricate relationships among heavy metals, shedding light on their sources and distribution. Geo-accumulation indices (Igeo) reveal moderate pollution levels in Fe and Cd, suggesting potential ecological risks. Conversely, Zn, Cu, Mn, and Pb remain within unpolluted ranges. The study enhances our understanding of heavy metal contamination in Ozomu Lake, emphasizing the need for tailored management and conservation strategies. Future research should explore seasonal variations and specific pollution sources in the lake's catchment area. This study contributes valuable insights into Ozomu Lake's environmental dynamics and underscores the importance of sustainable management for its long-term health and ecological integrity.

Ostracod palaeolimnology as an indicator of past human–environment interactions in Chełm Hills, south-eastern Poland

Both modern and historical data show that lake systems are undergoing profound changes because of human impacts from local to global scales. Research on this topic shows that human pressure on water systems can take various forms and is highly variable in time and space. This article presents the results of Ostracoda fauna research as an indicator of anthropogenic changes covering the time span from 7000 BP to the Mediaeval Period. The palaeoecological information (abundance and habitat preferences of Ostracoda assemblages) obtained in studies of fossil Ostracoda fauna communities amplified by palynological and archaeological data allowed to answer the following questions: (1) to what extent the impact of successive archaeological settlement cultures caused ecological changes in the lake catchment areas without directly affecting the lakes themselves, and when anthropogenic pressure caused transformations in the functioning of lake ecosystems and (2) whether the neolithization, as the first clearly legible stage of anthropopression, had a decisive influence on the functioning of lake ecosystems. Results of Ostracoda fauna studies have been compared with archaeological data available in the literature and multiproxy paleoenvironmental data previously published in a study of lake sediments in the Chełm Hills in South-Eastern Poland. Presented results of study of Ostracoda in lake sediments as a bioindicators of anthropogenic impact suggest that the pressure of prehistoric settlement in older phases (up to the early Middle Ages) was most clearly reflected in the landscape, while the functioning of lake ecosystems was disturbed only by the periodic increase in lake trophic status. A substantial change resulting from the analysis of the subfossil Ostracoda in all the studied lake ecosystems occurred in the phase of settlement related to the Early Middle Ages, which was reflected in the permanently changed species composition of the fauna.

Scales matter: regional environment factors affect α diversity but local factors affect β diversity of macroinvertebrates in Thousand Islands Lake catchment area

A more profound comprehension of various facets of biodiversity is essential for advancing sustainable governance of biodiversity and its associated ecosystem services. In this study, we delved into the composition of beta diversity within macroinvertebrates communities in the Thousand Islands Lake catchment area. Subsequently, we investigated the factors influencing the diverse facets of macroinvertebrates alpha and beta diversity, and ultimately employed structural equation modeling to analyze the pathways through which both regional environmental factors, like climate and land use, and local environmental variables collectively impact distinct facets of alpha and beta diversity within the ecosystem. Our results showed that (i) taxonomic and phylogenetic beta diversities were primarily determined by turnover, while functional beta diversity is predominantly determined by nestedness; (ii) alpha and beta diversity are primarily influenced by spatial variables, with local environment and climate ranking the second, and land use explaining the lowest proportion according to the results of variance partitioning; (iii) alpha diversity is mainly affected by regional variables, especially climatic factors (precipitation) while beta diversity is more affected by local variables, especially hydrological factors (depth) revealed by the structural equation modeling. These results offer compelling evidence that biodiversity composition, ecological drivers, and the specific pathways of influence vary across different scales. Future studies of macroinvertebrates could focus on different facets of alpha and beta diversity as well as consider the effects of environment variables at different scales, which would provide new insights into potential patterns of community associations.

Development of multivariate standardized drought index for large lake basins based on the copula function: A case study of Hongze Lake Basin, China

Study regionThe Hongze Lake Basin, China. Study focusA drought index is an essential tool for monitoring and prediction, and the construction of a comprehensive drought index is at the cutting edge of current drought research. Considering the regulation effect of lakes, a new drought index aimed at large lake catchment areas, namely the Multivariate Standardized Drought Index for Lakes Basin (MSDILB), can comprehensively characterise meteorological and hydrological drought. Here, the Standardised Precipitation Evapotranspiration Index (SPEI), Standardised Runoff Index (SRI), and MSDILB drought indices were used to evaluate the evolution of drought in the study area. Moreover, the response and conversion relationships between the basin’s hydro-meteorological elements and the regulation of the lake were explored. New hydrological insights for the RegionThe results indicate that: 1) in a dry year, the spatial-temporal heterogeneous runoff in the basin is redistributed by the storage and regulation of large lakes, thereby reducing the frequency of drought events; 2) the MSDILB drought index merges the characteristics of hydrological drought and meteorological drought indices and can monitor the evolution of drought events in lake basins; 3) the MSDILB drought index can sensitively capture the effects of lake hydrological regime change on drought events in the basin. Thus, it has the advantage of comprehensively characterising the drought conditions in large lake basins.

Evaluation of the upper lakes of the Erhai watershed in China based on water quality, land cover, and macrobenthic invertebrates.

In this study, three lakes, Cibi Hu, Haixi Hai, and Xi Hu, in the upper reaches of the main inflow rivers in the northern part of Erhai Lake were selected as the research objects. Based on the water environment monitoring indicators, land cover data, and lake macrobenthic community observation data, the non-parametric Kruskal-Wallis test, spatial analysis and community structure analysis were used to quantitatively assess the water environment and ecological status of the lakes. Using the Pollution Tolerance Index (PTI), the potential utility of macroinvertebrate communities as indicators of water ecological quality was investigated. The results showed that Cibi Hu and Haixi Hai have similar characteristics on water environmental quality. The physical and chemical indexes of water quality, the land cover of the lake catchment area, and the PTI index of the benthic community showed that Xi Hu was the most affected by human disturbance; the water ecological condition was the worst; and the environmental protection pressure was the greatest. In general, PTI analysis based on benthic fauna is convenient and can reflect the basic conditions of the aquatic benthic environment keenly, which is worthy of promotion.

Land Use and Climate Change Effects on Streamflow and Nutrient Loads in a Temperate Catchment: A Simulation Study

Climate and land use changes impact catchment hydrology and water quality (WQ), yet few studies have investigated the amount of land use changes required to meet specific WQ targets under future climate projections. The aim of this study was to determine streamflow and nutrient load responses to future land use change (LUC) and climate change scenarios. We hypothesized that (1) increasing forest coverage would decrease nutrient loads, (2) climate change, with higher temperatures and more intense storms, would lead to increased flow and nutrient loads, and (3) LUC could moderate potential nutrient load increases associated with climate change. We tested these hypotheses with the Soil and Water Assessment Tool (SWAT), which was applied to a lake catchment in New Zealand, where LUC strategies with afforestation are employed to address lake WQ objectives. The model was calibrated from 2002 to 2005 and validated from 2006 to 2010 using measured streamflow (Q) and total nitrogen (TN), total phosphorus (TP), nitrate (NO3-N), and ammonium (NH4-N) concentrations of three streams in the catchment. The model performance across the monitored streams was evaluated using coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) metrics to provide a basis for model projections. Future scenarios incorporated LUC and climate change (CC) based on the Representative Concentration Pathway 8.5 and were compared to the baseline streamflow and WQ indicators. Consistent with our hypotheses, Q, TN, and TP loads were predicted to decrease with afforestation. Specifically, afforestation of 1.32 km2 in one of the monitored stream sub-catchments (subbasin 3), or 8.8% of the total lake catchment area, would result in reductions of 11.9, 26.2, and 17.7% in modeled annual mean Q, TN, and TP loads, respectively. Furthermore, when comparing simulations based on baseline and projected climate, reductions of 13.6, 22.8, and 19.5% were observed for Q, TN, and TP loads, respectively. Notably, the combined implementation of LUC and CC further decreased Q, TN, and TP loads by 20.2, 36.7, and 28.5%, respectively. This study provides valuable insights into the utilization of LUC strategies to mitigate nutrient loads in lakes facing water quality challenges, and our findings could serve as a prototype for other lake catchments undergoing LUC. Contrary to our initial hypotheses, we found that higher precipitation and temperatures did not result in increased flow and nutrient loading.

Limnological responses to environmental changes during the last 3,000 years revealed from a varved sequence of Lake Lubińskie (western Poland)

Sediments from Lake Lubińskie, western Poland, were investigated to determine the limnological responses to environmental changes during the last 3,000 years. To identify the mechanisms driving the eutrophication in the lake, we distinguished six lithozones along with five major varve microfacies. An age-depth model based on varve counting and radiometric measurements was established resulting in final age of 946 +113/-144 before the Common Era at the bottom of the composite profile. Varve microfacies as well as geochemical, pollen, and diatom data was used to determine major phases of landscape and lake ecosystem transformations. Our data shows that until the 4th century of the Common Era, conditions in the lake were stable. Several shifts occurred before the first millennium, when changes were observed in every proxy as a response to the increased agricultural activity in the area as well as climate fluctuations. The highest frequency of shifts was observed from the 17th century onward and mirrored further deforestation (decrease in arboreal pollen), accelerated erosion (increase in Ti), increased nutrient delivery (increased total nitrogen content), and better ventilation of the water body (higher Mn/Fe ratio). Simultaneously, the lake became more eutrophic as a response to changes in the lake catchment area. Our study suggests that inferred lake-level changes are primarily related to human activity in the catchment area.

Test of Mercury (Hg) Content in Mozambique Tilapia Fish (Oreochromis Mossambicus) from Lake Rawa Taliwang Nature Tourism Park, West Sumbawa Regency

Rawa Taliwang Lake Natural Tourism Park is a freshwater waters located in West Sumbawa Regency with an area of ​​819.20 ha. Rawa Taliwang Lake Natural Tourism Park is dominated by various types of fish, so that local people catch fish in this lake to meet their consumption needs and for sale. In addition, the lake's catchment area also holds mining potential, especially gold. Small-scale gold mining, mostly found in the mountains and hills around catchment area Lake Rawa Taliwang. This mining uses liquid mercury as a gold binder from the ore. Some waste that has an impact on the end of lake water so that it can affect the lake ecosystem. Therefore, research is needed to determine the amount of mercury (Hg) in tilapia mozambique fish (Oreochromis mossambicus) from Rawa Taliwang Lake Natural Tourism Park. This study uses a quantitative descriptive method. In this study, sampling was carried out by purposive sampling at 3 location points with 3 repetitions. The research sample used 9 tilapia Mozambique fish. The data obtained were analyzed using the Atomic Absorption Spectrophotometry (AAS) method. The results showed that the mercury content in tilapia mozambique fish was &lt; 0.001 ppm. So it can be said that in the flesh of tilapia fish no heavy metal mercury (Hg) was detected.

Correlation between catchment land use/cover and macrophyte assessment of lake ecological status

The Water Framework Directive (WFD) provides the basis for developing a system to protect and restore the aquatic environment. Macrophytes are one of the groups of organisms for determining ecological status of lakes. Using partial least squares regression (PLS-R), we showed relationships between conductivity and chlorophyll a (to a lesser extent nutrient concentrations) and Ecological State Macrophyte Index (ESMI) values. However, catchment land use/cover (LU/LC) appears to be the important factor affecting macrophyte diversity as expressed by ESMI. The presence of significant correlations was found for the catchment area determined from surface runoff using the platform SCALGO Live, based on a permanently updated numerical terrain model and an accurate land use/cover database used in Poland BDOT10k. The Corine Land Cover (CLC) database commonly used in the EU appeared to be of insufficient resolution. We have shown a high positive impact of the presence of wetlands and reservoirs in the catchment on ESMI values and negative for agricultural and urbanized areas. Obtaining information on lake catchment land use and land cover is costless. Relating LU/LC to lake macrophyte assessment methods allows this no-cost method to be included in the set of biological methods for assessing lake condition. Understanding the factors that determine the condition of lakes is fundamental to managing them according to the requirements of the WFD. The results of our study indicate that the integration of lake catchment area planning with lake water management is imperative.

The spatio-temporal distribution of elements in the bottom sediments of Lake Onego and small lakes located on the catchment area of Onego Ice Lake

The work presents the results of a comprehensive mineralogical and geochemical study of Late Pleistocene-Holocene bottom sediments of Lake Onego and small lakes located in the territory belonging to Onego Ice Lake. Methods of ICP-MS, atomic absorption spectrometry, X-ray fluorescence analysis, X-ray phase method (XRD), scanning electron microscopy (SEM), and gamma-spectrometric method were used. The geochemical composition of the terrigenous fraction reflects the mineral composition and is permanent for the all bottom sediments cores of Lake Onego and small lakes during time interval about 12,000 years. For the first time, detailed mineralogical studies of sediments have shown that the composition of mineral associations of the terrigenous fraction is similar in the bottom sediment cores of Lake Onego and small lakes. The association of authigenic minerals in bottom sediments is distinguished by the presence of pyrite framboids in small lakes, and crystalline aggregates of Fe-phosphate, ferruginous illites and chlorites in Lake Onego. Sedimentation rates established by the study of correlations the indicator technogenic radioisotope 137Cs and atmospheric 210Pb. In the bottom sediments of small lakes, sedimentation rates vary from lake to lake, as well as in various areas of Lake Onego in the range from 0.05 cm/year to 0.30 cm/year.

Lake eutrophication: Control of phytoplankton overgrowth and invasive aquatic weeds

AbstractThis brief review describes the major causes of lake cultural eutrophication and assesses different strategies applied to control or reduce the negative consequences of this eutrophication. Excessive nutrient inputs, particularly from agricultural lands through non‐point source runoff, are among the main causes of cultural eutrophication on a global scale. Reducing nutrient inputs from agricultural lands through management of lake catchment areas, therefore, is an integral part of any effort to control lake eutrophication. Nutrient enrichment results in algal blooms and creates favourable condition for the invasion of a lake by alien aquatic weeds, making this invaluable freshwater resource unsuitable for many purposes, including drinking, agricultural and industrial water resources, fishing, transportation and recreational purposes. A major part of this review addresses attempts made to address the negative impacts of eutrophication by restoring water quality. Several research outputs discussing bottom‐up and top‐down control mechanisms were utilized for the present review. Much emphasis has been given in the literature regarding the use of biomanipulation as a promising and sustainable solution for controlling eutrophication. Biomanipulation tools used to control cyanobacteria and algal bloom have involved zooplanktivorous fish removal, piscivorous fish stocking, daphnia stocking, benthivorous fish removal, planktivorous fish stocking and mussel stocking. Further, some insect and fungal species have been used as biological control agents in an effort to control invasive aquatic weeds in tropical lakes. Although this review is limited in its analysis and explanation of the drawbacks associated with each described biomanipulation method, it can be deduced that biomanipulation generally exhibits considerable potential for controlling or reducing phytoplankton overgrowth and aquatic weed invasions, assuming it is also integrated with strategies to control external nutrient loadings to lakes.

Mapping Chini Lake (Pahang, Malaysia) using Sentinel-2 images to determine the effect of acid mine drainage in the pre- to post-COVID-19 restriction period.

Mining activities in the Chini Lake catchment area have been extensive for several years, contributing to acid mine drainage (AMD) events with high concentrations of iron (Fe) and other heavy metals impacting the surface water. However, during the restriction period due to the COVID-19 outbreak, anthropogenic activities have been suspended, which clearly shows a good opportunity for a better environment. Therefore, we aimed to analyze the variation of AMD-associated water pollution in three main zones of the Chini Lake catchment area using Sentinel-2 data for the periods pre-movement control order (MCO), during MCO, and post-MCO from 2019 to 2021. These three zones were chosen due to their proximity to mining areas: zone 1 in the northeastern part, zone 2 in the southeastern part, and zone 3 in the southern part of the Chini Lake area. The acid mine water index (AMWI) was a specific index used to estimate acid mine water. The AMWI values from Sentinel-2 images exhibited that the mean AMWI values in all zones during the MCO period decreased by 14% compared with the pre-MCO period. The spatiotemporal analysis found that the highest polluted zones were recorded in zone 1, followed by zone 3 and zone 2. As compared with during the MCO period, the maximum percentage of increment during post-MCO in all zones was up to 25%. The loosened restriction policy has resulted in more AMD flowing into surface water and increased pollution in Chini Lake. As a whole, our outputs revealed that Sentinel-2 data had a major potential for assessing the AMD-associated pollution of water.

Lands Cover Dynamics of Siais Lake Catchment Area, Tapanuli Selatan District, Indonesia

The Siais Lake Catchment Area (SLCA) is a water resource that includes various types of land cover and land use in Rianiate village, Angkola Sangkunur sub-district, and Tapanuli Selatan district. The SLCA lake catchment area has altered the land cover and increased the surface area of Siais Lake. The purpose of this study was to determine the type of land cover that changed in the Siais lake catchment area between 1990 and 2018. The land cover classification was obtained using Landsat 5 and Landsat 8 OLI images. Make use of supervised classification. Forest, plantation, bare land, paddy field, settlement, waterbody, shrub, and swamp were the land covers identified in the Lake Siais catchment area. Plantations had the highest percentage of land cover increase from 1990 to 2018, with an increase of 3,995.87%, while paddy fields had the highest decrease, with a decrease of 93.77%. .

Conceptual hydrological model-guided SVR approach for monthly lake level reconstruction in the Tibetan Plateau

Study regionTibetan Plateau (TP) Study focusLakes in the TP that are subject to low human activity serve as an important indicator for quantitative assessment of regional climate change. However, previous studies have mainly focused on annual changes in lake area, level, and storage because of limited monitoring stations, and long-term lake level reconstruction at monthly resolution remains challenging. We propose a conceptual hydrological model-guided monthly lake level reconstruction (WBM-SVR) approach that incorporates water balance models (WBMs) and support vector regression (SVR), to improve the training and testing sets compared with SVR alone through consideration of the hydrological process. The WBM-SVR approach integrates WBMs to select input factors, sub-process control equations to quantify the contributions of input factors, empirical parameters to characterize catchment uniqueness, and SVR for water level modelling. New hydrological insights for the regionPhysically guided WBM-SVR is more accurate than SVR in reconstructing monthly lake water levels. WBMs can quantify the hydrological process in the lake catchment area with efficient quasi-physical mechanisms and refine the input–output factors within lake hydrometeorology. The reconstructability, generalization capability, and transferability of WBM-SVR are validated for three different types of lakes (glacier-free inflow lake, glacier-free outflow lake, and glacier-fed inflow lake), and the reconstruction results indicate significant improvements in WBM-SVR compared with SVR. The WBM-SVR approach shows great promise for achieving monthly lake level reconstruction.