Lake Catchment Research Articles

A study on the erosion hazard rate of Limboto Lake catchment area

Damages to the land resources, mainly those happening on the drainage basin at Alo, Gorontalo occur in consequence of degradation of the ground surface layer as hit by raindrops and rainwater flow that carry soil surface. This issue becomes quite serious due to illegal logging and agricultural land conversion, mostly for maize fields as one of Gorontalo’s top commodities. As an attempt to analyze the problems, this study is undergone through field observation and documentation. This study covers aspects of socio-biogeophysical characteristics of the Alo drainage basin and analyzes the level of soil surface erosion and tolerable erosion rate. The result shows that 98.75 percent of erosion hazard is classified into low-to-moderate, covering approximately 6,874.721 hectares. Meanwhile, 1.25 percent of the high-to-extreme level of erosion hazard is 98.79 hectares wide. This suggests that the inappropriate use of land is more likely to increase the erosion hazard rate.

Study on Environmental Factors of Fluorine in Chagan Lake Catchment, Northeast China

The Chagan Lake Catchment is located in the midwest of Songnen Plain, which is a typical high fluoride groundwater area. High fluoride water has an important impact on the economic development and ecosystem stability of Chagan Lake. In this study, the spatial distribution characteristics and influencing factors of fluorine in Chagan Lake Catchment are discussed by using hydrochemistry and mathematical statistical analysis. The groundwater in the study area was characterized as Na+-rich and Ca2+-poor, with a high pH value and high HCO3– content. The average concentration of F– was 3.02 mg/L, which was the highest in Qian’an County. The dissolution of fluorine-containing minerals and the desorption of F– in soil provided the source of F– in groundwater, while calcite and dolomite precipitation, cation exchange, and evaporation concentration provided favorable conditions for F– dissolving, migration, and enrichment in water. In addition, the concentration of F– in surface water was 4.56 mg/L, and the highest concentration was found in Hongzi Pool and Hua’ao Pool. The elevated concentrations of F– in both surface water and groundwater in the study were affected by human factors, such as rice planting and water conservancy project construction.

Plateau lake ecological response to environmental change during the last 60 years: a case study from freshwater Lake Yangzong, SW China

The effects of anthropogenic activity and climate change on lake ecosystems for nine large plateau lakes in Yunnan Province have recently received much attention; however, most studies have focused on the deepest lake sediments and ignored the lake sediments adjacent to the populated area. To evaluate the sedimentation rates and ecological changes, four 210Pb- and 137Cs-dated sediment cores were collected along the long axis of Yangzong Lake, a fault-controlled north-south strike lake located in Yunnan Plateau in July 2006 and July 2016, respectively. We combined a biological indicator (diatom assemblage) with geochemical indicators (total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP)) for core S0 in the southern part of the lake to examine the ecological changes in response to anthropogenic disturbances within the lake over the last 60 years. The results showed that the sedimentation rate in the southern part of the lake (S1) was significantly higher than that in the central (S2) and northern (S3) parts of the lake. Redundancy analysis (RDA) and Pearson correlation analysis identified significant correlations between TP and Aulacoseira granulata, Cyclotella ocellata, and Cyclotella rohomboideo-elliptica (correlation coefficients: − 0.66, − 0.63, and 0.81, respectively, p < 0.01). There was a clear shift in the diatom community from oligotrophic to eutrophic species becoming dominant after the 1990s, coinciding with the intensifying human activities around the lake. Furthermore, there were two periods of diatom absence in core S0, which was associated with two periods of rapid depositional events. These are likely associated with the intensification of industry, mining, road construction, and agriculture within the lake catchment. These findings highlight the sensitivity of freshwater ecosystems in the shallow-water area of a lake to human activities, with implications for future water quality in fault-controlled lakes.

Estimation of soil erosion and sediment yield concentration across the Kolleru Lake catchment using GIS

Flat lakes with a large catchment area are especially affected by sediment inputs. The Kolleru Lake catchment (south-eastern India) with a surface area of approximately 6121 km2 belongs to such types of lake basins. The study’s main objective was the assessment of both soil erosion and sediment yield concentration rate of the Kolleru catchment. The study was conducted using the revised universal soil loss equation (RUSLE) model due to its simple and good applicability for soil erosion estimation. Data such as rainfall, soil texture, topography, crop cover management, and support practice factor were integrated into the modeling using RUSLE and ArcGIS. Field data were used both to analyze the soil texture and the slope length factor. The results showed that average annual soil loss was estimated with 13.6 t/ha/year, classifying the Kolleru Lake Basin under a very high erosion rate category. About 38% of the catchment area has encountered slight soil loss. Areas covered with moderate, strong, severe, very severe erosion potential zones are 29%, 17%, 9%, and 5.5%, respectively. This study identified that upland areas with less vegetation cover exported high potential erosion rates. Unlike the soil loss, the sediment delivery ratio values for the catchment were not affected by land use, while it showed a strong relationship with the catchment drainage system. Whereas, the average annual sediment yield was determined with 7.61 t/ha/year, had identified with the same pattern of the soil erosion. Catchment topography, vegetation, drainage system, soil properties, and land use cover played a major role in exporting the highest sedimentation. The outcome of these studies can be used among others to identify critical erosion areas on a pixel basis for the planning of erosion management practices.

Stages of soil development in the coastal zone of a disappearing lake\u2014a case study from central Poland

PurposeThe aim of this study was to estimate the impact of lake disappearance, groundwater table fluctuations, and some aspects of human pressure on stages of soil cover development in the catchment of Lake Rakutowskie.Materials and methodsResearch was conducted in soil chronosequence composed of eight soil profiles located in 785-m-long transect. Soils were sampled every 10 cm. Physical and chemical properties were determined with the use of disturbed and undisturbed samples. Radiocarbon dates were obtained for the bottom part of peat in each soil profile. The mineral composition of selected soil samples was determined using the X-ray diffraction (XRD) method. Additionally, the hydrological conditions were continuously monitored from July 27, 2013 to September 23, 2014.Results and discussionAn increased rate of shallow lakes overgrowth and final disappearance is a commonly observed process in the European lowlands. This paper presents and discusses the influence of changes in the range of the Lake Rakutowskie wetlands complex (central Poland) and water level fluctuations on soil cover transformation in the immediate vicinity of the lake. Five major phases of soil cover development (from Subaquatic Histosols (Limnic) to Hypereutric Regosol (Drainic, Humic)) were hypothetically reconstructed based on detailed studies of soil physical and chemical properties, mineral composition, water level fluctuations, and radiocarbon dating. The degree of peat decomposition in the studied profiles increased with the distance from the contemporary lake surface. Along with the progressive dehydration and mineralization of organic soils, their physical and chemical properties deteriorated, which is visible, e.g., in soil structure, and mineral and chemical composition (especially TOC and TN). Obtained radiocarbon ages of selected samples indicate that the oldest peat layers developed about 5856 cal BCE (6970 ± 70 14C BP), while the youngest were deposited about 1074 cal CE (980 ± 40 14C BP)–1573 cal CE (300 ± 35 14C BP). Hydrological studies indicate a progressive process of lake disappearance.ConclusionsThe process of soil cover transforming of the studied area takes place relatively quick, mainly recently due to the influence of human activity. Based on these results, it can be predicted that the lake will most likely disappear in a relatively short time, and the soil cover will be entirely in the fifth phase (P5) of evolution.

Connectivity between lentic and lotic freshwater habitats identified as a conservation priority for coho salmon

Abstract Juvenile Pacific salmon exhibit diverse habitat use and migration strategies to navigate high environmental variability and predation risk during freshwater residency. Increasingly, urbanization and climate‐driven hydrological alterations are affecting the availability and quality of aquatic habitats in salmon catchments. Thus, conservation of freshwater habitat integrity has emerged as an important challenge in supporting salmon life‐history diversity as a buffer against continuing ecosystem changes. To inform catchment management for salmon, information on the distribution and movement dynamics of juvenile fish throughout the annual seasonal cycle is needed. A number of studies have assessed the ecology of juvenile coho salmon (Oncorhynchus kisutch) during summer and autumn seasons; catchment use by this species throughout the annual cycle is less well characterized, particularly in high‐latitude systems. Here, n = 3,792 tagged juvenile coho salmon were tracked throughout two complete annual cycles to assess basin‐wide distribution and movement behaviour of this species in a subarctic, ice‐bearing catchment. Juvenile coho salmon in the Big Lake basin, Alaska, exhibited multiple habitat use and movement strategies across seasons; however, summer rearing in lotic mainstem environments followed by migration to lentic overwinter habitats was identified as a prominent behaviour, with two‐thirds of tracked fish migrating en masse to concentrate in a small subset of upper catchment lakes for the winter. In contrast, the most significant tributary overwintering site (8% of tracked fish) occurred below a culvert and dam, blocking juvenile fish passage to a headwater lake, indicating that these fish may have been restricted from reaching preferred lentic overwinter habitats. These findings emphasize the importance of maintaining aquatic connectivity to lentic habitats as a conservation priority for coho salmon during freshwater residency.

Anthropogenic Pressure- A Potential threat to Biodiversity. An Evidence from Macroinvertebrate Community of Dal Lake, Kashmir, India

A survey was conducted to assess the macroinvertebrate community and water quality of the Dal Lake of Kashmir in relation to anthropogenic pressure on the lake. Macroinvertebrates were collected by D-frame net and Ekman’s dredge. Physico-chemical analysis of water was performed by following methods of American public health association. During the survey 28 macroinvertebrate taxa were recorded representing phylum Annelida (8 taxa), Arthropoda (13 taxa), and Mollusca (7 taxa). Mean population density of macroinvertebrates was estimated 6376 ind./m2. The annelids were found dominant (2524 ind./m2) followed by arthropods (2411 ind./m2) and molluscs (1441 ind./m2). Mean value of Biological indices was computed 2.41 (Shannon’s index), 0.89 (Simpson’s index), 1.55 (Margalef’s index), and 0.17 (Pielou evenness index). Water quality assessment revealed eutrophic, alkaline, highly productive, hard water type, and organically polluted nature of lake waters. Water quality, sewage influx, organic wastes, agricultural wastes, and macrophytes were observed as the influential factors in determining the patterns in diversity, distribution, and composition of macroinvertebrate community in the lake. Anthropogenic pressure at lake catchments was observed as a major force behind the current ecological conditions of lake. The study concludes that the lake is under anthropogenic and pollution stress and urges for immediate restoration measures. Keywords : Macroinvertebrates, diversity, water quality, urbanization, pollution

Mountain aquatic Isoëtes populations reflect millennial-scale environmental changes in the Bohemian Forest Ecosystem, Central Europe

In this study we aim to investigate millennial-scale dynamics of Isoëtes, a type of macrophyte well adapted to oligotrophic and clear-water lakes. Despite its wide distribution during the Early Holocene, nowadays Isoëtes is considered as vulnerable or critically endangered in many Central European countries. Using a multi-proxy palaeoecological reconstruction involving Isoëtes micro- and megaspores, pollen, plant macrofossils, macro-charcoal, diatoms and chironomids from four lakes (Prášilské jezero, Plešné jezero, Černé jezero, Rachelsee) located in the Bohemian Forest Ecosystem mountain region in Central Europe, we reconstruct Isoëtes dynamics and discuss how local environmental factors impacted its distribution and abundance during the Holocene. Our results show regionally concurrent patterns of Isoëtes colonisation across all lakes beginning 10,300–9300 cal yr BP, and substantially declining around 6400 cal yr BP. Results from Prášilské jezero imply that Isoëtes decline and collapse in this lake reflect gradual dystrophication that led to the browning of lake water. This is evidenced by a shift in diatom assemblages towards more acidophilous taxa dominated by Asterionella ralfsii and by a decrease in total chironomid abundance and taxa sensitive to low oxygen levels. Dystrophication of Prášilské jezero was linked with the immigration of the late-successional tree taxa ( Picea abies and later Fagus sylvatica and Abies alba), peatland expansion, and decreasing fire activity. Multi-site comparison of pollen records suggest that these vegetation-related environmental changes were common for the whole region. Our study demonstrates the sensitivity of Isoëtes to millennial-scale natural environmental changes within the surrounding lake catchment.

Investigation of factors affecting surface pollen assemblages in the Balikun Basin, central Asia: Implications for palaeoenvironmental reconstructions

To interpret pollen assemblages in terms of past vegetation, it is important to consider the source of pollen for any given lake profile containing sufficient pollen, and the way it arrives at its preservation site. It is of value to know the proportion of the pollen assemblage derived from the lake catchment and that which was airborne. This has been a long-neglected issue for lakes from arid areas of central Asia. In this study, we used two modified Cour (M-Cour) traps in different biomes (steppe and desert) to collect airborne pollen in the enclosed Balikun Basin during the non-flowering season (late autumn to early winter). The pollen assemblages from the traps are similar with large proportions of herbaceous and (sub-)shrub taxa such as Artemisia and Chenopodioideae. This implies a shared long-distance transport component, in addition to pollen derived from the local vegetation. These xeromorphic species are ubiquitous in the inland desert and/or steppe areas beyond the lake basin, and their pollen is likely to be carried by the wind into lake sediments from a broad area, leading to high percentages of Artemisia and Chenopodioideae pollen in lake surface-sediments. Pollen types from upstream areas (e.g. Picea, Cyperaceae, Leguminosae) are barely found in samples from the river mouth and lake surface-sediments. Thus, we speculate that the transport of pollen by inflow streams makes little contribution to the overall pollen budget in Balikun Lake. This is probably related to the low transport capacity of the surface runoff into the lake, as precipitation is low and there is limited meltwater from snow and glaciers in the surrounding mountains. Pollen assemblages from the near-shore lakebed, which have a high percentage of Chenopodioideae pollen (74.8%), represent only the very local environment, reflecting the expansion of saline-alkali habitats rather than desert. Sedimentary archives from the near-shore lakebed will thus overestimate the desert Chenopodioideae pollen component and hence cause unreliable vegetation or climate reconstructions. We also found the local vegetation composition and pollen depositional processes could significantly bias the ratio of Artemisia/Chenopodioideae (A/C), reducing its effectiveness as an index to distinguish steppe from desert. We suggest using A/C ratios from lake surface-sediments which have a large airborne pollen source area in arid areas, as a better reference for down-core fossil pollen.

Future Hydrology of the Cryospheric Driven Lake Como Catchment in Italy under Climate Change Scenarios

We present an assessment of climate change impact on the hydrology of the Lago di Como lake catchment of Italy. On one side, the lake provides water for irrigation of the Po valley during summer, and on the other side its regulation is crucial to prevent flood risk, especially in fall and winter. The dynamics of lake Como are linked to the complex cryospheric hydrology of its Alpine contributing catchment, which is in turn expected to change radically under prospective global warming. The Poli-Hydro model is used here to simulate the cryospheric processes affecting the hydrology of this high-altitude catchment. We demonstrated the model’s accuracy against historical hydrological observations, available during 2002–2018. We then used four Representative Concentration Pathways scenarios, provided by three Global Circulation Models under the AR6 of IPCC, to project potential climate change until 2100. We thereby derived daily series of rainfall and temperature, to be used as inputs for hydrological simulations. The climate projections here highlight a substantial increase in temperature at the end of the century, between +0.61° and +5.96°, which would lead to a decrease in the total ice volume in the catchment, by −50% to −77%. Moreover, there would be a decrease in the contribution of snow melt to the annual lake inflow, and an increase in ice melt under the worst-case scenarios. Overall, the annual Lake inflows would increase during autumn and winter and would decrease in summer. Our study may provide a tool to help policy makers to henceforth evaluate adaptation strategies in the area.

HIGH RESOLUTION MINERALOGICAL CHARACTERIZATION OF SEDIMENTS - LAKE BOLĂTĂU-FEREDEU (ROMANIA)

The catchment (bedrock and soil) and sediments of lake Bolătău, Romania were studied by high resolution multi-methodological investigations to characterize paleoenvironmental and formation conditions. Particle size analyses, optical and cathodoluminescence microscopy, FTIR-ATR and Raman spectroscopy, X-ray powder diffraction, and XRF were applied for microtextural, chemical, micro-mineralogical and embedded organic material characterization and distribution of the sediments, especially concerning geochemical conditions, like pH and redox potential change. Our results support physical and chemical weathering in the process of soil formation with appearance of the new minerals appear (10Å sized phyllosilicates and clay minerals). Comparison of these studies offer possible differentiation of syn- and diagenetic mineralization, the clarification of debris contribution, microbial mediation and complex mineralization via decomposition of cell and extracellular polymeric substance. Based on the analyses on the abrasives, a suboxic environment prevailed in the depositional area and considerable microbial contribution is proposed via accumulation of lake sediments.

Пространственный анализ и интегральная оценка факторов потенциальной опасности биоразнообразию биогеоценозов водосборного бассейна озёр Белое и Липповское (Кургальский полуостров, Россия)

In the context of maintaining a constant threat of biodiversity loss, it is urgent to solve the problem of improving and creating new methods for assessing the factors of biodiversity change. Due to the complexity and multidimensity of the task, the authors are invited to use the method of analyzing and synthesizing indicators with information deficit (ASPID method). As an example of using the method, this article presents the results of studies of potential risk factors for biodiversity loss in the catchment area of two adjacent lakes on the Kurgalsky Peninsula. As objects of the assessment chosen taxa biogeocenoses of the peninsula. In accordance with the procedure for estimating the ASPID-method for each taxon, a composite indicator was calculated. The composite indicator characterizes the level of the total risk of biodiversity loss. It is formed on the basis of a system of individual indicators and taking into account their weight. The system of individual indicators reflects the effect of anthropogenic and natural anthropogenic factors. Calculations of composite indicators have formed the basis for the compilation of thematic maps of the integral assessment of hazards. Thematic maps are compiled using geographic information systems (GIS). Assessment maps allow you to identify areas of the territory with a high and low degree of danger. The analysis of the maps revealed differences in the spatial distribution of estimates, which allows to identify areas of the lake catchment with a low and high degree of risk of biodiversity loss. In particular, it is noted that the main threat comes from anthropogenic factors, since the “strong” and “most severe” degree of danger is detected in 42% of biogeocenoses, and in the case of anthropogenic-natural factors only in 21%. The threat of anthropogenic-natural factors to the biodiversity of biogeocenoses is most pronounced on the western border of the catchment area. In the eastern part of the catchment area, the influence of anthropogenic-natural factors is less noticeable. Since the solution of the problem of biodiversity conservation affects the ecology of territories and in particular catchment areas, it can be useful in determining the ecological status and ecological well-being of water bodies and their catchment areas.

Forest Damage and Subsequent Recovery Alter the Water Composition in Mountain Lake Catchments

Forest Damage and Subsequent Recovery Alter the Water Composition in Mountain Lake Catchments

Сток наносов и мутность воды основных притоков Ладожского озера

The vast catchment area of the Lake Ladoga is characterized by variety of underlying surface types and a complex hydrographic network. The processes of eutrophication of the southern littoral areas of the Lake Ladoga determine the relevance of assessing the removal of solid matter from the river flow to the estuaries of the tributaries of the Ladoga. Observations of sediment runoff of the main tributaries the Lake Ladoga were not carried out. In this regard, for each tributary were selected rivers-analogues the main criteria in the selection was the slope, the grain size of sediments and the catchment area (water availability). The modeling of annual solid runoff and turbidity of the Ladoga tributaries is based on an analytical formula for sediment flow by M.V. Shmakova and a stochastic model of annual solid runoff (M.V. Shmakova). According to the calculations, the annual flow of sediment entering the Ladoga water area is about 432 thousand t/year. The main sources of sediment are three major tributaries of the Lake Ladoga – the Svir, Volkhov and Vuoksa rivers, which account for 253 thousand t/year or 59 % of the total amount of sediment received in the lake. However, these watercourses have the smallest annual module solid flow, due to retention of sediment of backwater areas before hydroelectric dams on these rivers and as a consequence, a decrease in the overall sediment discharge. At the same time, the average annual solid runoff modulus for the Ladoga lake catchment area is 1.53 t/(km2·year), which corresponds well to the previous estimate of this value for the territory under consideration. The analysis of the annual module of solid runoff showed a good correspondence between the obtained values of this value and the conditions for the formation of solid runoff in the catchment, the characteristics of its soils.

ИННОВАЦИОННОЕ РАЗВИТИЕ ТЕПЛОЭНЕРГЕТИКИ РЕГИОНА: ЭКОЛОГО-ЭКОНОМИЧЕСКИЙ АСПЕКТ

The article deals with topical issues of innovative modernization of the electric power complex of the Baikal region. The region includes the territories of the Irkutsk Region, Buryatia and a significant part of the territory of Mongolia within the boundaries of the lake catchment system. Baikal. It is noted that the economic landscape of the Baikal region is formed largely due to the presence of the Angara cascade of hydroelectric power plants and is known as one of the largest producers of electricity. At the same time, the further development of hydrogenation is limited by the level of technological development and the need to protect the biodiversity of the territory. It is noted that at present the ecosystem of the Angara River is significantly disturbed, in connection with which the development of alternative types of electric generation, such as coal-fired power and the use of renewable energy sources, is considered expedient. The high resource potential of the territory, namely the presence of significant coal reserves, contribute to the development of thermal energy, but since this is associated with high environmental risks, the development of environmentally safe and economically feasible coal energy technologies comes to the fore. The paper examines the prospects and provides a brief ecological and economic assessment of innovations in the heat power industry of the region, through the use of coal-water fuel and generator gas - a product of coal gasification. The brief comparative analysis of traditional thermal power engineering and thermal power engineering based on innovative energy carriers carried out in the work demonstrates a sufficiently high efficiency of the considered energy technologies. The expediency of using these technologies is explained by the higher efficiency of the upgraded equipment and a much more sparing mode of impact on the unique ecosystem of the Baikal region, which confirms their high ecological and economic significance.

Assessment of the Ecological and Geographical Condition of the Basin System Lakes Strilske (Hydrological Monument of Nature)

Topicality. The available information on specific lakes of nature protection fund (NPF) objects, primarily of local significance, is limited to brief information on morphometric and hydrological characteristics, information on the rare component of aquatic organisms and the species diversity of the adjacent catchment areas. This state of affairs does not benefit the development of protected areas and encourages ecological and geographical searches of lakes or lake-basin systems, which are part of the NPF. Purpose is to assess the ecological and geographical condition of the lake basin system Strelske (hydrological monument of nature) for cadastral needs of NPF objects of Polissya region of Ukraine. Methods of regional constructive-geographical limnology, landscape-limnological analysis, soil-geochemical profiling of lake catchments, GIS-cartographic modeling. Results of the study are presented in the form of a cartographic model of the spatial-typological structure of the lands of the lake catchment. Shooting and substantiation of its geoecological condition, bathymetric map of the lake and morphological-morphometric and hydrological calculations of the LBS. The hydrochemical parameters of the lake were analyzed according to the block of indicators of salt composition, tropho-saprobiological characteristics and substances of toxic action. The lithological composition and capacity of the bottom sediments of the lake are estimated, the graphs of radial migration of chemical elements and compounds at one of the probing points are constructed and the qualitative composition of the lake sapropel is substantiated. Using GIS technologies, a landscape map of the natural-aqual complex of the lake was built. Shooting and landscape-metometric assessment of its morphological structure. Conclusions. The basin system has in the past undergone anthropogenic transformations as a result of reclamation nature management, which has limited the share of surface runoff into the lake. The lake water exceeded the MPC by 1.7 times the chemical oxygen demand, 1.6 times the biological oxygen demand and 2 times the total iron consumption. The lake basin is 65.7% filled with bottom sediments, which are represented mainly by organo-iron sapropel. The littoral aqua facies of the lake suffer the greatest anthropogenic load, which is connected with the recreational activities of the seasonally functioning recreation center.

Pesticides and toxicity on aquatic larvae: A study on loktak lake Catchment area

Pesticides and toxicity on aquatic larvae: A study on loktak lake Catchment area

Fate of Contaminants of Emerging Concern in a Sinkhole Lake, Florida, USA

Highly karstified carbonate platforms such as Florida are characterized by rapid infiltration rates, highly permeable bedrock and the direct connection to the below aquifer through the high density of sinkholes. This combination of physical features makes the groundwater and aquifers highly vulnerable to contamination from synthetic chemicals commonly referred to as contaminants of emerging concern (CECs). The use of septic tanks, otherwise referred to as onsite water treatment systems (OWTS), promotes the introduction of CECs into the environment. In order to study the impacts of CECs from OWTS on a karst landscape, water, sediment, and vegetation samples were collected in a sinkhole lake surrounded by residential housing using this waste disposal method. The main question of this research project is what is the fate of CECs from OWTSs effluent within the catchment of a sinkhole lake? Liquid chromatograph mass spectrometry was used to analyze the samples for the presence of CECs. It was found that the relative quantity of CECs in the individual constituents is dependent upon 1) the hydrophobicity and polarity of the individual compound, 2) the specific sampling site, 3) the topography gradient, and 4) for vegetation, the connectedness of the sample type to the sediment. Hydrogeological studies have found that the sinkholes of the area are all connected to the below aquifer. Consequently, these CECs pose a risk of the contamination of the groundwater. This study is a temporal snapshot, that being the dry season of Florida which is most likely the time of lowest CEC contamination. It is imperative that sampling extend into the wet season when flushing of CECs from the OWTS may increase their concentrations in both the lake but also the aquifers especially since residents use well water as their source of potable water. While this study is based in Florida, we strongly suspect that our findings and recommendations are applicable more generally as OWTS are used throughout the many karst regions of the world.

Late Holocene periods of copper mining in the Eisenerz Alps (Austria) deduced from calcareous lake deposits

• Geochemical proxies indicate mining activity during the Bronze and Iron Ages. • Variations of δ 15N and δ 34S point towards lake catchment changes. • Pb enrichments in the calcareous deposits are not consistent with supra-regional amtospheric Pb peaks. Palynological studies and archaeological discoveries suggest repeated extensive prehistoric copper mining in the Eisenerz Alps (Styria, Austria). In an attempt to reconstruct the specific temporal evolution of copper (Cu) mining activity in this area from the Bronze Age to the medieval period, this article presents records of elemental variations, trace elemental enrichments of Cu, nickel (Ni), zinc (Zn), arsenic (As), cadmium (Cd), antimony (Sb) and lead (Pb) as well as light stable isotopes of nitrogen ( δ 15 N) and sulfur ( δ 34 S) as preserved in a calcareous sediment core retrieved from Lake Leopoldstein (Eisenerz). While the multi-element geochemical approach covers a time period from the Early Bronze Age to the mid-medieval period (2070 BCE – 850 CE), isotopic analyses were conducted up to a core depth of 660 cm, corresponding to about 3100 BCE. A comparative study of the parameters revealed strong indications of regional mining during the mid-Bronze Age (∼15th – 14th century BC), the Hallstatt period (∼8th – 6th century BC) and in the late La Tène period (∼3st century BC). Statistical evaluation of the data highlighted a good correlation of trace elements associated with local copper ores (fahlores, chalcopyrite). Enrichments of Pb, in contrast, are characterised by a more substantial deviation from the general trace element trend and are mainly linked to lithogenic input. Overall, the results of this study underscore the necessity of a broad-based multi-proxy approach in order to reconstruct periods of past mining activity based on the analysis of calcareous lake sediments. Especially, δ 15 N and δ 34 S revealed no particular potential for identifying past mining activity. However, both proxies were helpful for inferring erosional changes in the lake catchment, and thus for unraveling the interdependencies between geogenic and anthropogenic signals. Our study sheds new light on prehistoric copper mining in Central Europe.

"Safe and just operating space" for the sustainable development of the social-ecological system in the Liangzi Lake Catchment, Hubei Province, China.

The increases of human activities threaten the health of the earth's ecosystem, and pre-sent a big challenge to regional sustainable development and environment conservation. How to maintain a safe ecological environment together with social and economic development is an important issue for sustainable development. Under the theoretical framework of "safe and just operating space", we integrated lake sediment records, environmental monitoring data, and socio-economic data in Liangzi Lake Catchment, analyzed the status of key eco-environmental processes and achievement degree (the completion of the current value of social basic indicators relative to the target value) of residents' social welfare, and constructed a "safe and just operating space" for the sustainability of local social-ecological system. The results showed that the indicators including freshwater utilization, cultivated land resources, air quality, soil and sediment regulation, and chemical pollution in the catchment had exceeded the environmental ceiling and were at the "dangerous" level, which should be regulated in the future. As for the social welfare, the achievement degree of clean water, sanitation facility, and industrial innovation were relatively low. The per capita GDP was negatively correlated with soil and water conservation and air quality, indicating the negative effects of social and economic development on water, soil, and air. With multi-source environmental data, especially long-term limnological records, we effectively reconstructed the historical environmental change process, revealed the deficiency of environment and residential well-being in local social ecosystem management, which would provide important insights for regional sustainable development.