Lake States Research Articles

Composition characteristics and metal binding behavior of macrophyte-derived DOM (MDOM) under microbial combined photodegradation: A state closer to actual macrophytic lakes

In actual lakes, the “unstable components” of macrophyte-derived DOM (MDOM) are always degraded and cannot exist abidingly, but the environmental impact brought by it is ignored. In this study, MDOM from Potamogeton crispus was extracted to carry out microbial combined photodegradation (M-Photodegradation) and fluorescence titration experiments. Then the traits and metal binding reaction of MDOM under M-Photodegradation were analysed and compared with the features of lake-derived DOM (LDOM) from point monitoring of Dongping Lake through EEM-PARAFAC, 2D-SF-COS, and 2D-FTIR-COS. The results showed that the features of MDOM after M-Photodegradation were closer to those of LDOM. The degradation amplitudes were 93.53% ± 0.53% for C4 in microbial degradation and 78.31% ± 0.74% for C3 in photodegradation. Correspondingly, both were hardly detected in LDOM. Protein-like substances and aliphatic C–OH were preferentially selected by Cu2+, while humic-like matter and phenolic hydroxyl O–H responded faster to Pb2+. Although the binding sequences remained unchanged after M-Photodegradation, the LogKCu and LogKPb of components decreased overall, indicating increased environmental risks. This study proves that the refractory MDOM retained after degradation was more consistent with the actual state of macrophytic lakes and provides more information for the treatment of heavy metal pollution in lakes.

Native molluscs alleviate water quality impacts of invasive crayfish

Freshwaters are considered to be the most vulnerable ecosystems facing biological invasions, and the red swamp crayfish (Procambarus clarkii) is one of the most widespread aquatic invasive species in the world. P. clarkii has negative impacts on water quality in the lakes that it invades by, for instance, increasing their turbidity and nutrient concentrations and reducing macrophyte biomass. However, native taxa such as snails and mussels could potentially help to maintain a clear-water status in lakes by grazing on periphyton or by phytoplankton filtration. To examine the potential negative effects of P. clarkii on the clear-water state in lakes dominated by the macrophyte Vallisneria denseserrulata and the potential for native species to buffer these effects, we tested the crayfish impact in the absence and presence of the snail Bellamya aeruginosa and the mussel Sinanodonta woodiana at different biomasses. In the presence of crayfish, total suspended solids, total phosphorus, and chlorophyll a concentrations significantly increased compared to the control treatments without crayfish. However, when crayfish coexisted with snails or mussels, these three environmental variables all decreased in concentration compared to the crayfish-only treatment. Low (500 g/m2) and high (1500 g/m2) snail or mussel biomass had similar buffering effects. Macrophyte biomass in the crayfish and high mussel biomass treatment was 43 % higher than in the crayfish-only treatment. Native molluscs therefore alleviated the negative effects of crayfish on lake water quality and promoted native macrophyte growth. We conclude that a thriving native mollusc community may help in maintaining the clear-water state in lakes following crayfish invasion.

Concentración de nitrogeno y fósforo en el agua de lluvia de Corrientes (Argentina)

Inorganic nitrogen, phosphorus, pH and conductivity in rainwater were measured at Corrientes (27°27’S, 58°47’W) during 1984-1985. Mean water pH was 5.97 (4.60 - 7.15) and mean conductivity was 11.5 uS/cm (2.7 - 21 uS/cm) showing good waterquality. Concentration showed positive correlation with the length of time betweensuccessive rains and were inversely correlated with precipitation volume. Both inorganic nitrogen concentrations and fallout, were low (mean conc.: 315 µg Ninorg/1 mean fallout: 190 µg Ninorg/m2 yr) when compared with the reported figures in unpolluted locations. Total phosphorus concentration (36 µg TP/1) and fallout (16.5 µg TP/m2 yr) were relatively high probably because of dust contribution. Fallout rates resulted an order of magnitude lower than those of very polluted areas.lt was shown that nutrient fallout is important in determining trophic status of shallow lakes and ponds profuselly distributed in Corrientes province.

Zooplankton in brackish water bodies of the plain territory of the Altai territory in the vegetation season of 2022

The zooplankton of three small brackish lakes (Bulatovo, Korostelevskoye and Markovskoye) located in the plain territory of Altai Krai was studied in 2022. Data on the main characteristics of the zooplankton habitat are presented. An assessment of the ecological state of lakes is given based on qualitative and quantitative indicators of zooplankton. The taxonomic composition and main quantitative characteristics of zooplankton in the spring, summer and autumn periods are characterized. Seasonal dynamics of quantitative indicators and changes in the taxonomic composition of zooplankton were noted. The lowest quantitative indicators of zooplankton development were noted in the spring season (April). All identified representatives of zooplankton were cosmopolitans. Common to all lakes are 5 taxa of crustaceans and rotifers (Keratella quadrata, Filinia longiseta, Daphnia magna, Cyclopidae ind., Diaptomidae ind.). In the spring and autumn seasons, copepods dominated in abundance and biomass, reaching 99.9% of the zooplankton population. Differences in the composition of the dominant taxa in the summer season were noted between the lakes. In the lake Bulatovo was dominated in numbers by rotifers due to Brachionus quadridentatus, and in biomass by cladocerans due to Daphnia magna. In the lake Korostelevskoe, the dominant taxonomic group in terms of numbers was copepods, the basis of which were Diaptomidae ind., in terms of biomass — cladocerans due to Diaphanosoma brachiurum. Only in the lake In Markovskoe, copepods — Diaptomidae ind. — dominated in numbers and biomass. The zooplankton of the studied lakes was characterized by a poor species composition, but high summer numbers and biomass (from 342 thou. eq./m3 and 7.13 g/m3 in Lake Markovskoe to 1895 th. eq./m3 and 33.7 g/m3 in Lake Bulatovo). In the summer season, the zooplankton biomass of the lake. Markovskoye belonged to reservoirs of the α-eutrophic type, lakes Bulatovo and Korostelevskoye were of the polytrophic type. The majority of noted species (60%) were indicators of β-mesosaprobic conditions.

Changes and transport of microplastics in the riverbed of the mainstream below the Three Gorges Dam of the Yangtze River

The Yangtze River has always been considered an important river for transporting microplastics into the sea. However, there is still a lack of understanding of the degree of microplastic pollution in the sediment of the middle and lower reaches of the Yangtze River, which has affected the estimation of microplastic flux into the sea. In this study, microplastics in sediments from 55 stations in the middle and lower reaches of the Yangtze River were investigated, including 48 mainstream stations, 5 confluence stations, and 2 lake stations. Microplastics were detected in 34 stations, ranging from 0 to 71.04 n/kg of dry weight. The average concentrations of microplastics in the mainstream, confluence and lake were 6.16 ± 8.87, 23.91 ± 11.2, and 43.95 ± 27.09n/kg of dry weight, respectively. Of all the microplastics found in this investigation, fiber (59.52 %) forms the main type in terms of shape; PET is the most abundant microplastic species, accounting for 51.19 %. Sewage treatment plants are the most likely source of microplastics in sediment, and sediment from tributary estuaries, lake mouths, and lakes is an important sink of microplastics. Terrain, sediment transport load, biofilm, and flow velocity are important factors affecting microplastic settlement. Although there are multiple microplastic enrichment areas, the high flow velocity during the flood season makes it difficult for microplastics to remain in the sediment of the Yangtze River bed. This indicates that microplastics in riverbed sediments have little influence on the flux into the sea during flood season. This study is the first large-scale investigation of microplastics in riverbed sediments in the Yangtze river basin.

A continuous classification of the 476,697 lakes of the conterminous US based on geographic archetypes

AbstractA variety of classification approaches are used to facilitate understanding, prediction, monitoring, and the management of lakes. However, broad‐scale applicability of current approaches is limited by either the need for in situ lake data, incompatibilities among approaches, or a lack of empirical testing of approaches based on ex situ data. We developed a new geographic classification approach for 476,697 lakes ≥ 1 ha in the conterminous U.S. based on lake archetypes representing end members along gradients of multiple geographic features. We identified seven lake archetypes with distinct combinations of climate, hydrologic, geologic, topographic, and morphometric properties. Individual lakes were assigned weights for each of the seven archetypes such that groups of lakes with similar combinations of archetype weights tended to cluster spatially (although not strictly contiguous) and to have similar limnological properties (e.g., concentrations of nutrients, chlorophyll a (Chl a), and dissolved organic carbon). Further, archetype lake classification improved commonly measured limnological relationships (e.g., between nutrients and Chl a) compared to a global model; a discrete archetype classification slightly outperformed an ecoregion classification; and considering lakes as continuous mixtures of archetypes in a more complex model further improved fit. Overall, archetype classification of US lakes as continuous mixtures of geographic features improved understanding and prediction of lake responses to limnological drivers and should help researchers and managers better characterize and forecast lake states and responses to environmental change.

Lake Sevan. Past, present, and future state of a unique alpine lake

Lake Sevan, a large, deep, alpine lake in the Lesser Caucasus is the focus of this Special Issue of the Journal of Limnology. It was an outstanding ecosystem 100 years ago characterised by excellent water quality, rich biodiversity with a high level of endemism, wide-ranging beds of macrophytes along the shores and a productive and sustainable fish production. Due to its beauty, natural history, and contributions to social and economic welfare it is also a cultural heritage for the Armenian Nation including its large diaspora.

LHYMO: A new Water Framework Directive‐compliant multimetric index to assess lake hydromorphology and its application to French lakes

Abstract Hydromorphology provides a physical framework for aquatic biocenoses. Its condition directly affects the quality of habitats available for fauna and flora, and its assessment is therefore useful for biodiversity and water quality conservation, as well as for restoration programmes required by European and national directives. In this study, a site‐specific index of Lake HYdroMOrphology, LHYMO, was developed to provide a quantitative assessment of the hydromorphological status of natural and non‐natural lakes that is consistent with European Committee for Standardization (CEN) standards and that can be used for different purposes, including the implementation of the Water Framework Directive (WFD) and of the Habitats Directive. This new LHYMO index includes nine metrics related to the morphological WFD quality elements (QEs) and six metrics related to the hydrological WFD QEs, all of which are considered to support biological elements. The reference conditions were defined for each metric using an original approach: the degree of alteration is measured in relation to the natural characteristics of each lake, relative to a state that ‘would be expected in the absence of disturbances’. Besides its use for regulatory purposes, this index is also a suitable tool for monitoring the efficacy of hydromorphological restoration projects or to help target effective conservation measures on lakes. Application of this index to 72 French lakes provides the first quantitative and homogeneous assessment of the hydromorphological quality of lakes over a whole territory and gives the first overview of the hydromorphological status of lakes in France, with classification into five classes ranging from ‘high’ to ‘bad’. LHYMO is already operational for large French lakes as it relies mostly on reference datasets available at a national scale, and it may also be used in a wider scope through gathering or completing data from other sources.

Vertical Distribution of Diatoms Analysis to Determine the Condition of Rawapening Lake in the Past through Cluster Analysis with the Bray-Curtis Model

Vertical Distribution of Diatoms Analysis to Determine the Condition of Rawapening Lake in the Past through Cluster Analysis with the Bray-Curtis Model

Food quality upgrade of carbon from submerged macrophytes by flagellates via a heterotrophic pathway can stimulate growth of Daphnia magna.

Submerged macrophytes play crucial roles in maintaining the stability of clear-water states in shallow lakes. Recent stable isotope studies have shown that crustacean zooplankton can utilize submerged macrophyte carbon, but macrophytes alone cannot support the growth and reproduction of such grazers, being deficient in highly unsaturated fatty acids (HUFA). We hypothesized that flagellates feeding on macrophytes can synthesize HUFA and thereby support crustacean zooplankton. To test this hypothesis, we conducted a feeding experiment in which Daphnia magna were provided with a diet of submerged macrophyte Hydrilla verticillata detritus which had been degraded by lake microbes. The chlorophyte Scenedesmus bijuga and undegraded macrophyte detritus were used as controls for comparison of Daphnia's performance. Using biochemical analysis, we examined how the degradation process affected the food quality of the macrophyte. Flagellates were subsequently isolated from the degraded macrophyte and cultured heterotrophically to detect their HUFA synthesis. The 5-day degraded H. verticillata showed significantly higher HUFA concentrations than undegraded macrophyte detritus. They supported better Daphnia performance than undegraded macrophyte, being comparable with S. bijuga. Two isolated flagellates (SL-1 and SL-2), identified as Ochromonas sp. and Poterioochromonas sp., were found to contain HUFA when cultured heterotrophically without dietary sources of fatty acids, suggesting their HUFA synthesis ability. Our results demonstrate that submerged macrophytes may thus indirectly support crustacean zooplankton via flagellate mediation. As crustacean zooplanktons are of key importance for water quality in the grazer control of phytoplankton, this microbial facilitation may contribute to the maintenance of macrophyte clear-water conditions in shallow lakes.

«Көлсай көлдері» Мемлекеттік ұлттық табиғи парк (МҰТП) насекомдары (Insеcta)

In 2023, in the course of the work, field studies were conducted in the Taldy Gorge, Lake 1-Kolsai and Lake Kayyndy and new data on the species composition of insects were obtained. Extensive material has been collected to determine the species composition, biology, ecology and economic significance of insects living on the territory of the Kolsai Lakes State Research and Production Enterprise. As a result of research conducted in 2023, 6 species of 2 families of the Orthoptera order, 2 species of 2 families of the Dermaptera order, 4 species of 2 families of the Hemiptera order (Auchenorrhyncha), 1 species of 1 family of the Neuroptera order, 15 species of 6 families of the Lepidoptera order, 7 species of 2 families of the order Hymenoptera, 12 species from 6 families of the order Coleoptera. Thus, as a result of the research conducted in 2023 on the territory of the Kolsai Lakes Scientific Research Center, 47 species of insects from 7 orders were identified. The species Parnassius patricius Niepelt, 1911 from the family of sailboats (Papilionidae) found in the study area is listed in the Red Book of Kazakhstan as a “rare species”.

Development of lake macroinvertebrate-based multimetric index for monitoring ecological health in North Central Nigeria.

The use of organisms like macroinvertebrates in developing bioassessment tools, such as multimetric indices (MMIs), is gaining global recognition in monitoring the health status of lakes. The transition from traditional methods of physico-chemical parameters is due to the financial and time costs involved in their analysis while failing to provide accurate early warning signals on ecosystem conditions. Currently, there is scanty information on the use of MMIs in the conservation and management of lakes in Nigeria. This study aimed at developing a macroinvertebrate-based MMI to assess the ecological status of lakes in North Central Nigeria. The study was conducted on Tagwai and Old Gawu Lakes, from April to October 2022. Sampling sites were clustered based on organic pollution and categorized into reference (four) and impaired (four) sites. Out of 54 macroinvertebrate-based candidate metrics, only five were selected after discriminatory, stability, and redundancy tests (performed using R software). The final metrics were abundance of Ephemeroptera + Trichoptera; abundance of Coleoptera + Ephemeroptera; Gastropoda richness; Shannon Wiener index; and percentages of shredders + predators + scrapers, hereafter referred to as North Central Nigeria-Lakes Multimetric Index (NCN-LMMI). The NCN-LMMI values ranged as follows: 21-25, 16-20, 11-15, and 5-10 corresponding to categories I, II, III, and IV for water quality, as indications of good, fair, poor, and very poor ecological status of the lake, respectively. The developed NCN-LMMI will be a useful tool for aquatic resource managers and environmentalists to assess the ecological condition of lakes, mainly the North Central Nigeria municipal lakes.

Application of Remote Sensing Technology in the Field of Lake Pollution Control and Monitoring

Lake pollution has always been one of the significant environmental concerns for humanity. This article explores the hazards of lake pollution and analyzes whether remote sensing technology is meaningful for monitoring and controlling lake pollution in the context of abundant remote sensing resources. The results show that remote sensing technology can help people monitor the pollution status of lakes and assess the effectiveness of their management more easily. This article investigates the role of remote sensing technology in eutrophication, organic pollution, and heavy metal contamination, along with the challenges faced. It also examines the application of remote sensing technology in lake degradation, restoration, and management. It concludes that remote sensing technology can indeed play a role in lake pollution monitoring and control, offering benefits such as reduced labor, time, and spatial costs. The article aims to find more reasonable ways to address lake pollution control and lake environmental management issues while minimizing the ecological impacts of lake pollution.

Historic and recent trends of cyanobacterial harmful algal blooms and environmental conditions in Clear Lake, California: A 70-year perspective

Clear Lake is a large, natural lake in northern California, USA, with many beneficial uses but also substantive environmental issues. The lake has a long history of water quality problems including mercury contamination, pesticide usage, invasive species, and high rates of primary production. In recent years, an increase in cyanobacterial harmful algal blooms (cyanoHABs) has been documented in the lake, adding to the environmental issues faced by aquatic species present in the lake and the local community. Extensive observations of various physical, chemical, and biological parameters in Clear Lake began in the mid-1900s. The most pertinent of these data sets and findings have been reviewed and analyzed with the intent of improving our understanding of the causes and drivers of cyanoHABs, toxin production, and identifying data gaps. Several parameters including average annual water temperature have remained relatively constant over the past 70 years, although the seasonally averaged water temperatures have shifted in a manner that may now favor cyanobacterial dominance. Clear Lake has also witnessed recent changes in several environmental variables such as total phosphorus concentrations that might contribute to blooms. An analysis of lake conditions prior to and following the enactment of a total maximum daily load (TMDL) for phosphorus in 2007 indicates little measurable influence on total phosphorus concentrations in Clear Lake. The present trajectory of lake chemistry suggests that additional research and management efforts will be needed to address the recurrence of cyanoHABs in the future. Future lake management strategies should include consideration of the role of internal nutrient loads to lessen cyanoHABs. Furthermore, a better understanding of cyanobacterial community interactions and top-down effects on bloom formation within the lake can help guide future cyanoHAB management strategies.

Valdai Hills as the Cradle of the Volga River

The role of the Valdai Hills and the Valdai Lake area in ensuring the fullness of the sources of the Volga River and its current trends against the background of climate change is presented. It is shown that the “water-making functions” of the upland landscape are initially determined by two general properties of the relief: its invariance as a “framework of life” and its changeable evolution under the influence of endogenous and exogenous factors. The “Cradle of the Volga” in relation to the Valdai Hills and specifically the Baltic-Caspian watershed is a set of conditions that allow the formation of runoff in the upper reaches of the river. Among the main ones that determine the conservation of runoff in the average annual volume are the state of rivers, lakes, and swamps, the minimization of anthropogenic impacts (regulation of runoff, plowing, catchment, deforestation, development and pollution of the coastline, etc.), and, in general, nature protected areas (creation of them at the source of the river). Based on the materials from the monitoring of the climate and hydrological regime of the region carried out by the Valdai branch of the State Hydrological Institute (Valdai), the main trends of the Volga River runoff factors in the upper reaches have been identified. The share of water-regulating, water-saving, and assimilation functions in the total volume of ecosystem services in the landscapes of the Valdai Hills is shown. It is concluded that the modern growth of recreational impact on the catchments of the sources of the Volga River can reduce the positive effect of the functioning of nature protected areas on them. The priority issues in preserving the “cradle of the Volga” should be the regulation of recreational loads on the landscapes of the Valdai Hills, rehabilitation of disturbed forest ecosystems, and monitoring of the volume and quality of runoff.

The Current Trophic State and Water Quality of Lake Onego

The trophic state and water quality of Lake Onegо were assessed under climate warming and changes in anthropogenic load over the past 30 years. The water body retains its natural oligotrophic state during the summer stratification according to the concentration of chlorophyll a. A small amount of readily mineralizable organic matter in water determines the low level of development of saprophytic bacteria, corresponding to xenosaprobic and β-oligosaprobic waters. Only the Kondopogskaya Bay of Lake Onego is characterized by a higher level of trophy (mesotrophic) and water saprobity (β-mesosaprobic) due to pollution by wastewater from the pulp and paper mill and waste from trout farms. Local “bloom” of cyanobacteria of in the open area of the lake was observed during the anomalous heating of the epilimnion in the summer of 2022 for the first time in the 50-year history of research. The increase in the concentration of humic substances in the water of the bays as a result of climate warming at this stage did not lead to a change in the level of saprophytic bacteria.

Trophic status of a shallow lake in Inner Mongolia: long-term, seasonal, and spatial variation

The study of lake-trophic status drivers and their variable effects over space and time can assist in the management of lake eutrophication. Winter dynamics in lake trophic status are rarely evaluated, yet they could vary drastically from the more commonly sampled summer patterns. This represents a key blindspot in our knowledge because ice sheets affect nutrient distribution (e.g., nitrogen and phosphorus), light infiltration (translucency), and phytoplankton propagation (Chl-a concentration). We examined long-term (2011–2020) changes in the trophic status (trophic level index; TLI) of Lake Wuliangsuhai, a shallow lake situated in a cold and arid region, using Generalized Additive Models (GAMs). The results suggested a significant decrease in eutrophication of Wuliangsuhai Lake over the study period, with TLI decreasing from 61.7 (moderately eutrophic) in 2011 to 49.9 (mesotrophic) in 2020. TLI was significantly higher over winter (p < 0.05), with the rank of seasons in terms of TLI of: winter (58.7) > summer (54.7) > autumn (54.2) > spring (54.0). TLI of the ice-covered period (58.7) significantly exceeded that of the ice-free period (54.3) (p < 0.05). There were also significant spatial differences in TLI (p < 0.05). Factors driving the spatial and temporal heterogeneity in lake trophic levels included the water supplement, water depth, water temperature, external inputs of nutrients, hydrodynamic conditions (flow velocity), distribution of phragmites, and the location of the main diversion channel.

Patterns of Water Consumption in Longleaf Pine Restoration Areas and the Relationship with Cone Production

Monitoring water consumption dynamics across the geographic range of an ecosystem may indicate the possible variation and stress in a biome. Here, model output data based on remote sensing (1979–2022) were used to examine the water consumption dynamics and effects on cone production in three geographic margins in the longleaf pine’s range (i.e., Bladen Lake State Forest, Escambia Experimental Forest, and Kisatchie National Forest) under varying climatic conditions. Results indicated that the mean annual transpiration at Escambia was approximately 431 mm and that at Bladen and Kisatchie was 500 mm. Mean monthly transpiration peaked twice (June and October) at Escambia but only once (August) at Bladen and Kisatchie. The mean annual evapotranspiration ranged from approximately 900 mm at Kisatchie to about 791 mm at Escambia and Bladen. The mean annual transpiration/evapotranspiration ratio was about 0.65 at Bladen and 0.55 at Escambia and Kisatchie. A significant correlation existed between evapotranspiration and specific humidity across the sites on a monthly scale but not on a yearly scale. Significant negative relationships existed between precipitation and the ratios of transpiration/precipitation and evapotranspiration/precipitation on the yearly scale across the sites. Negative power relationships were observed between precipitation and the specific humidity/precipitation ratio on monthly and yearly scales. Cone production was generally highest in years with moderate water consumption. These results provide baseline information on how hydrological and ecological processes of longleaf pine forests interact with climate across broad spatial and temporal scales.

The current state of Lake Dålk (Larsemann Hills, East Antarctica)

The study focuses on the current state of englacial Lake Dålk (Larsemann Hills Oasis), which was completely devastated in January 2017 by a catastrophic outburst and formed again in February 2020. A set of works including ground-penetrating radar (GPR) profiling, geodetic survey, core drilling, thermometric measurements and isotopic analysis was performed. As a result, new data were obtained about the modern boundaries of the reservoir, ice thickness and depths, as well as about the peculiarities of freezing of the lake after re-formation. Based on the field data obtained, one-dimensional mathematical modeling of Lake Dålk freezing was carried out, the results of which showed further scenarios of its evolution.

Extremely 13C-enriched dolomite records interval of strong methanogenesis following a sulfate decline in the Miocene Ries impact crater lake

In impact crater lakes, the lacustrine sedimentary records may not solely reflect climatic changes but also potential erosional effects from lithologically distinct impactite formations. The hydrochemical and biogeochemical processes during the deposition of the Nördlinger Ries impact crater lake, which fall in the range of the mid-Miocene Climate Transition, were studied by analysing microcrystalline authigenic carbonates in a drill core succession, using stable oxygen and carbon isotopes in conjunction with biomarkers. These investigations revealed an early sulfidic interval characterized by thiophenes, iso- and anteiso-C15:0 acids derived from sulfate reducing bacteria, and dolomites with low to intermediate δ13Ccarb values. The subsequent distinctive interval is characterized by extremely 13C-enriched dolomite (δ13Ccarb up to +20.93 ± 0.05‰ V-PDB), decline of iso- and anteiso-C15:0 acids and is rich in an Archaea-derived archaeol that is 13C-enriched (−14.7‰), indicating extensive methanogenesis in sulfate-depleted lake porewater during early diagenesis. The sulfate decline results from successive sulfate reduction when replenishment by sulfate-bearing inflow water is limited. The carbonates exhibit enriched 18O due to pronounced evaporation in a long-resided water body and enriched 13C by methanogenesis. A change in provenance of water derived from the sulfur-rich suevite (impact melt-bearing breccia) and crystalline source rocks to the sulfur-poor Bunte Breccia (continuous ejecta blanket) is required. Intermittently high Si/Al and Zr/Al at the high δ13C interval suggests sporadic short-term runoff increase, leading to fluctuating physiochemical lake conditions. A subsequent decline in both δ13Ccarb and archaeol indicates a decreasing lake level with intermittent subaerial exposure events, supported by bioturbation and mud cracks. The concomitant lake oxygenation is well supported by increasing Pr/Ph ratios and lipids derived from aerobic methanotrophs (13C-depleted 3-methyl-hopanoids). In the youngest unit, allochthonous lignites and biomarkers from lacustrine/soil sources appear, high total sulphur contents and thiophenes recur, and stable C and O isotope values decrease again. These observations suggest another major provenance change of the inflowing solutes, with increasing influx from weathered pyrite-bearing Jurassic claystones. These findings demonstrate that the climatic record expected from the stable carbon and oxygen isotopes of the Ries carbonates is strongly overprinted by hydrochemical and biogeochemical processes due to changing ion influx from substrate rocks, along the course of the successive ejecta erosion and catchment changes. Such an intrinsic control of lacustrine biogeochemical processes is also expected for other hydrologically closed impact crater lake basins, where catchment rocks with distinctively different lithologies are present.