Influence Of Surface Water Research Articles

Insights into the Nature of Formate Species in the Decomposition and Reaction of Methanol over Cerium Oxide Surfaces: A Combined Infrared Spectroscopy and Density Functional Theory Study

Formation of formate species on oxide surfaces plays a role in reactions for hydrogen production such as the water–gas shift and the steam-reforming of alcohols. It has been suggested that bridge formates are the most common and stable configuration on metal oxides. Ceria-based catalysts are important for these reactions where ceria is a “non-innocent” support. In this work, the nature of the formate species that are formed during decomposition and reaction of methanol on ceria surfaces have been studied using a combination of infrared temperature-programmed surface reaction (TPSR-IR) on a real powder catalyst support and density functional theory (DFT) together with statistical thermodynamics for model CeO2(111) surfaces. The influence of surface oxygen vacancies, hydroxyl groups, and water has been considered. Three different formate species have been identified (450–550 K). Initially, formates are adsorbed on the oxidized surface that is gradually hydroxylated by the release of hydrogen from methoxy gr...

Application of multivariate statistical analysis to incorporate physico-chemical surface water quality in low and high flow hydrology

Multivariate statistical methods, such as principal components analysis (PCA), discriminant analysis (DA) and general linear models (GLM) were applied to incorporate physico-chemical surface water quality in low and high flow hydrology in Northern Iran, based on analysis of the 7-day low flow index and existing water quality data. In view of this, 7-day low flows were calculated for 15 water years (1991–2006) at 15 monitoring stations. Eleven water quality parameters were extracted during the low flows from the water quality data and compared to water quality during high flows. Significant differences in water quality were noted for some monitoring stations and the pattern and magnitude of the statistically significant responses (t test, p < 0.05) varied among sites. PCA, was applied to the data sets of the two low and high flow periods, and resulted in three effective factors explaining 77.8 and 67.4 % of the total variance in surface water quality data sets of the two periods, respectively. The main factors obtained from PCA indicated that the parameters influencing surface water quality are mainly related to natural, point and non-point source pollution in the study area. DA provided an important data reduction as it used only three parameters, i.e. magnesium (Mg2+), calcium (Ca2+) and bicarbonate (HCO3 −) affording 60 % correct assignations, to discriminate between the two low and high stream flow periods. General regression models revealed that surface water quality parameters were explained by low and high flow and specific discharge. The results of this study can be useful for water managers for effective surface water quality management under climate change.

Assessing protozoan risks for surface drinking water supplies in Nova Scotia, Canada.

Protozoa, such as Cryptosporidium parvum and Giardia lamblia, pose a human health risk when present in drinking water. To minimize health risks, the Nova Scotia Treatment Standards for surface water and groundwater under the direct influence of surface water require a 3-log reduction for Giardia cysts and Cryptosporidium oocysts. This study determined the protozoan risk of municipal surface source waters in Nova Scotia, through the use of a pre-screening risk analysis of water supplies, followed by subsequent water quality analysis of the seven highest risk supplies. The water supplies were monitored monthly for 1 year to obtain baseline data that could be used for a quantitative microbial risk assessment (QMRA). The QMRA model outcomes were compared to the Health Canada health target of 10(-6) disability-adjusted life years/person/year. QMRA modeling shows that the treatment facilities meet the required log reductions and disability-adjusted life year target standards under current conditions. Furthermore, based on the results of this work, Nova Scotia should maintain the current 3-log reduction standard for Giardia cysts and Cryptosporidium oocysts. The results of this study show that a pre-screening step can help to inform water sources that are particularly vulnerable to protozoan contamination, which can lead to more focused, cost-effective sampling, and monitoring programs.

Hydrologic variability governs population dynamics of a vulnerable amphibian in an arid environment.

Dynamics of many amphibian populations are governed by the distribution and availability of water. Therefore, understanding the hydrological mechanisms that explain spatial and temporal variation in occupancy and abundance will improve our ability to conserve and recover populations of vulnerable amphibians. We used 16 years of survey data from intermittent mountain streams in the Sonoran Desert to evaluate how availability of surface water affected survival and adult recruitment of a threatened amphibian, the lowland leopard frog (Lithobates yavapaiensis). Across the entire study period, monthly survival of adults ranged from 0.72 to 0.99 during summer and 0.59 to 0.94 during winter and increased with availability of surface water (Z = 7.66; P < 0.01). Recruitment of frogs into the adult age class occurred primarily during winter and ranged from 1.9 to 3.8 individuals/season/pool; like survival, recruitment increased with availability of surface water (Z = 3.67; P < 0.01). Although abundance of frogs varied across seasons and years, we found no evidence of a systematic trend during the 16-year study period. Given the strong influence of surface water on population dynamics of leopard frogs, conservation of many riparian obligates in this and similar arid regions likely depends critically on minimizing threats to structures and ecosystem processes that maintain surface waters. Understanding the influence of surface-water availability on riparian organisms is particularly important because climate change is likely to decrease precipitation and increase ambient temperatures in desert riparian systems, both of which have the potential to alter fundamentally the hydrology of these systems.

A proposal for a groundwater habitat classification at local scale

Distribution of groundwater invertebrate communities in porous aquifers (and their habitats) varies on spatial scales and many attempts have been made to classify these on various scales. The new data-based approach, presented here, classifies the complex distribution of groundwater habitats on a local scale (i.e. along transects of &lt; 100 m) and merges the latest classification approaches at this scale. Data from a regional (i.e. approximately 100 km2) biogeographic groundwater survey was analysed in terms of stability of: community structure, different intensities of surface water influence, and occurrence, together with the distribution of stygobites within those groundwater ecosystems. On the investigated local scale, the faunistic communities’ composition is mainly depending on surface water influence, coupled with immision of dissolved oxygen and organic matter. Derived from this finding, five types of faunistic habitats are proposed: (I) Stressed groundwater habitats, (II) Stable groundwater habitats, (III) Rain fed groundwater habitats, (IV) Surface water fed groundwater habitats, and (V) Hyporheic habitats.

Effects of current-use fungicides and their mixtures on the feeding and survival of the key shredder Gammarus fossarum

Fungicides are frequently applied in agriculture and are subsequently detected in surface waters in total concentrations of up to several tens of micrograms per liter. These concentrations imply potential effects on aquatic communities and fundamental ecosystem functions such as leaf litter breakdown. In this context, the present study investigates sublethal and lethal effects of organic (azoxystrobin, carbendazim, cyprodinil, quinoxyfen, and tebuconazole) and inorganic (three copper (Cu)-based substances and sulfur) current-use fungicides and their mixtures on the key leaf-shredding invertebrate Gammarus fossarum. The feeding activity of fungicide-exposed gammarids was quantified as sublethal endpoint using a static (organic fungicides; 7 d test duration) or a semi-static (inorganic fungicides; 6 d test duration with a water exchange after 3 d) approach (n=30). EC50-values of organic fungicides were generally observed at concentrations resulting in less than 20% mortality, with the exception of carbendazim. With regard to feeding, quinoxyfen was the most toxic organic fungicide, followed by cyprodinil, carbendazim, azoxystrobin, and tebuconazole. Although all tested organic fungicides have dissimilar (intended) modes of action, a mixture experiment revealed a synergistic effect on gammarids’ feeding at high concentrations when using “independent action” as the reference model (∼35% deviation between predicted and observed effect). This may be explained by the presence of a synergizing azole fungicide (i.e. tebuconazole) in this mixture. Furthermore, lethal concentrations of all Cu-based fungicides assessed in this study were comparable amongst one another. However, they differed markedly in their effective concentrations when using feeding activity as the endpoint, with Cu-sulfate being most toxic, followed by Cu-hydroxide and Cu-octanoate. In contrast, sulfur neither affected survival nor the feeding activity of gammarids (up to ∼5mg/L) but reduced Cu-sulfate's toxicity when applied in a binary mixture. Sulfur-related metabolic processes which reduce the physiological availability of Cu may explain this antagonistic effect. For both fungicide mixtures, the present study thus uncovered deviations from the appropriate reference model, while ecotoxicological effects were observed at field relevant (total) fungicide concentrations. Additionally, for more than half of the tested single substances, a potential risk for Gammarus and thus for the ecological function mediated by these organisms was evident at concentrations measured in agriculturally influenced surface waters. These results suggest that risks to the fundamental ecosystem function of leaf litter breakdown posed by fungicides may not be adequately considered during the regulation of these compounds, which makes further experimental efforts necessary.

A geochemical study of the impact of irrigation and aquifer lithology on groundwater in the Upper Yakima River Basin, Washington, USA

The Yakima River, a major tributary of the Columbia River, is currently overallocated in its surface water usage in part because of large agricultural water use. As a result, groundwater availability and surface water/groundwater interactions have become an important issue in this area. In several sub-basins, the Yakima River water is diverted and applied liberally to fields in the summer creating artificial recharge of shallow groundwater. Major ion, trace element, and stable isotope geochemistry of samples from 26 groundwater wells from a transect across the Yakima River and 24 surface waters in the Kittitas sub-basin were used to delineate waters with similar geochemical signatures and to identify surface water influence on groundwater. Major ion chemistry and stable isotope signatures combined with principal component analysis revealed four major hydrochemical groups. One of these groups, collected from shallow wells within the sedimentary basin fill, displays temporal variations in NO3 and SO4 along with high δ18O and δD values, indicating significant contribution from Yakima River and/or irrigation water. Two other major hydrochemical groups reflect interaction with the main aquifer lithologies in the basin: the Columbia River basalts (high-Na groundwaters), and the volcaniclastic rocks of the Ellensburg Formation (Ca–Mg–HCO3 type waters). The fourth major group has interacted with the volcaniclastic rocks and is influenced to a lesser degree by surface waters. The geochemical groupings constrain a conceptual model for groundwater flow that includes movement of water between underlying Columbia River basalt and deeper sedimentary basin fill and seasonal input of irrigation water.

Identifying interactions between river water and groundwater in the North China Plain using multiple tracers

Interactions between river water and groundwater have been used to help understand the movement of water and to evaluate water quality in the semi-arid area of the North China Plain (NCP). Stable isotopes, chlorofluorocarbons (CFCs) and hydrochemistry were used to study the influence of surface water from the Xiao River on regional groundwater. Using a mass balance approach based on chloride concentrations, hydrogen and oxygen isotope ratios, the average fraction of surface water recharging to groundwater was 50–60 %. CFC results indicated that the groundwater recharge age varied from 22.5 to 39.5 years. The vertical flow velocity of groundwater was estimated at about 1.8–3.5 m year−1. Nitrate concentrations in groundwater varied from 9.42 to 156.62 mg L−1, and exceeded 50 mg L−1 in most aquifers shallower than 80 m bordering the Xiao River. The δ 15N-NO3 data indicate that the major sources of nitrogen in groundwater are human sewage and animal excreta. Because groundwater is the main source of drinking water, there should be concern about public health related to the elevated nitrate concentrations in the NCP.

Land Use–Land Cover Changes and Sewage Loading in the Lower Eastern Shore Watersheds and Coastal Bays of Maryland: Implications for Surface Water Quality

Aighewi, I.T.; Nosakhare, O.K., and Ishaque, A.B., 2013. Land use–land cover changes and sewage loading in the lower Eastern Shore watersheds and coastal bays of Maryland: Implications for surface water quality.Changes in land use and cover influence surface water quality and thus are a potential threat to water systems and coastal ecosystem health. The objectives of this study were to evaluate the influence of historical land use–land cover (LULC) changes and point-source sewage discharge on surface water quality of some lower Eastern Shore watersheds of Maryland. LANDSAT data for 1986–2006 was acquired and classified using Anderson level-1 classification system in ENVI 4.5, whereas LULC changes were detected in Arc-GIS 9.2 environment. Historical water monitoring and climatic data were obtained from Maryland Department of Environment–Chesapeake Bay Program, and National Oceanic and Atmospheric Administration, respectively. Nutrient loading data from wastewater treatment plants were obtained from Maryland Department of Environment and data analyzed using regression analysis and principal component analysis (PCA). The result shows that total phosphorous levels in the surface waters decreased significantly (p < 0.05) during the 20-year study period. However, using PCA, we determined that the declining P trend was attributable to the decreasing agricultural land use rather than the sewage discharge from wastewater treatment plants. The increase in urban land use and the resultant runoff to the water bodies may explain the declining trends in dissolved oxygen levels observed during the period, with serious implications for eutrophication. An empirical model developed for P in surface waters (r2 = 0.90) showed that the combination of point and nonpoint sources and land use/cover change factors are good predictors. The incorporation of quantitative LULC data component as well as point-source nutrient loading into existing models is highly recommended for a more holistic assessment of land-use influence on water systems in general.

Exploration of geothermal systems using hyperspectral thermal infrared remote sensing

Visible near infrared (VNIR), short-wave infrared (SWIR), and thermal infrared (TIR) remote sensing has long been used for geothermal exploration. Specific focus on the TIR region (8–12μm) has resulted in major-rock-forming mineral classes being identified and their areal percentages to be more easily mapped due in part to the linear mixing behavior of TIR emission. To understand the mineral compositional and thermal distribution of active geothermal surfaces systems, hyperspectral TIR data from the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) airborne sensor were acquired over the Salton Sea, CA geothermal fields by The Aerospace Corporation on March 26, 2009 and April 6, 2010. SEBASS collects 128 wavelength channels at ~1m spatial resolution. Such high resolution data are rarely available for this type of scientific analysis and enabled the identification of rare mineral assemblages associated with the geothermally-active areas. One surface unit with a unique spectrum, believed to be a magnesium sulfate of unknown hydration state, was identified for the first time in the SEBASS data. The abundance and distribution of this mineral varied between 2009 and 2010 likely due to the precipitation conditions. Data obtained by the SEBASS sensor were also regressed to the 32 channel spectral resolution of the Mineral and Gas Identifier (MAGI) airborne sensor in order to test sensitivity limits. At this lower spectral resolution, all surface minerals were still effectively identified and therefore validated data at MAGI resolution are still very effective for accurate surface compositional mapping. A similar approach used at active geothermal areas in other semi-arid regions around the world has the potential to better characterize transient mineralogy, identify “indicators minerals”, understand the influence of surface and ground water, and ultimately to locate new geothermal targets for future exploration. Furthermore, new Mineral and Gas Identification (MAGI) data serve as an excellent precursor for future spaceborne TIR data such as the system proposed for the Hyperspectral Infrared Imager (HyspIRI) instrument.

Round 1 LT2ESWTR Cryptosporidium Monitoring Results

Cryptosporidium data from the first round of source water monitoring under the Long Term 2 Enhanced Surface Water Treatment Rule were analyzed and evaluated. This rule, promulgated in 2006, requires public water systems treating surface water or groundwater under the direct influence of surface water (GWUDI) to conduct two rounds of source water monitoring and on the basis of the results to implement treatment addressing public health risk from Cryptosporidium. This article summarizes data‐cleaning efforts, sampling and analytical results, binning outcomes, oocyst recovery, and relationships between Cryptosporidium and Escherichia coli measurements. The data indicate that 7% of large systems must implement additional treatment. Small system estimates are unreliable because the data represent only 3% of applicable systems. In aggregate, Cryptosporidium occurrence was higher in flowing stream–type surface water sources compared with reservoir/lake‐type surface water sources or GWUDI supplies.

Matching metal pollution with bioavailability, bioaccumulation and biomarkers response in fish (Centropomus parallelus) resident in neotropical estuaries

Two neotropical estuaries affected by different anthropogenic factors were studied. We report levels of metals and metalloids in water and sediment as well as their influence on genetic, biochemical and morphological biomarkers in the native fish Centropomus parallelus. Biomarkers reflected the fish health status. Multivariate statistics indicated both spatial and temporal changes in both water and sediment, which are linked to the elemental composition and health status of inhabitant fish, showing the biggest influence of surface water, followed by sediments and interstitial water. Bioaccumulation in fish muscle was useful to identify elements that were below detection limits in water, pointing out the risk of consuming fish exceeding allowance limits for some elements (As and Hg in this case). Multivariate statistics, including physical, chemical and biological issues, presents a suitable tool, integrating data from different origin allocated in the same estuary, which could be useful for future studies on estuarine systems.

Temporal variation of arsenic and nitrate content in groundwater of the Duero River Basin (Spain)

High concentrations of arsenic (As) in groundwater of the Duero River Basin have created a public health concern in some provinces of Spain. However, the mechanism of As mobilization and influence of surface water–groundwater interaction, nutrients and different geochemical reactions on As removal have not yet been clearly reported. Therefore, this study investigated the possible mechanisms of As release, and temporal variations of As with respect to nitrate content in groundwater. Hydrogeochemical characteristics of groundwater sampled along three years in a region of central Spain showed high As contents exceeding EU guideline value of 10μg/l. Significant positive correlations were found between As and bicarbonate concentrations in water samples. These results suggest a possible mechanism of As mobilization from sediments to groundwater as follows: bicarbonate ions can displace HAsO42- adsorbed on surface of aquifer Fe oxyhydroxide, other minerals and sediments. In addition, the high pH values of the groundwater might also favor the As desorption processes. The results showed that As concentrations in water samples decreased along with the increase in nitrate concentrations across the whole period of study (2001, 2003 and 2007). The negative and significant correlations between As and nitrate contents in water reflect the temporal variation of As concentration due to the effect of surface water–groundwater interaction and nutrient input into groundwater. The increased use of nitrogen fertilizers and pig manure in agriculture practices increased the nitrate content in groundwater during the period of this study, which could have favored the precipitation of Fe oxyhydroxides and As adsorption.

Do residues of imidacloprid in surface water cause honeybee colony losses?

Honeybee colony mortality is a problem at a world wide scale. Insecticides in agriculture and horticulture might contribute, especially the neonicotinoid imidacloprid, which is a commonly used systemic insecticide that might induce several effects at sublethal concentrations. Furthermore it is very persistent in soil and water. At several locations in the Netherlands imidacloprid was found in the surface water in relatively high concentrations. The exceeding of the acceptable levels was suggested to be causally related to honeybee colony losses, and several groups in society are concerned. The aim of this study is to determine whether concentrations of imidacloprid in surface water influence honeybee mortality in the Netherlands. Therefore monitoring data of honeybee mortality from 2005, 2006, 2007 and 2009 and several covariates are used. Data of honeybee mortality are linked to maximum values of imidacloprid concentrations in surface water. For a realistic risk valuation, three foraging distances are used, i.e. 1000 meters, 3000 meters and 7500 meters. Peak concentrations of imidacloprid within a radius of 7500 meters around the colonies appeared negatively correlated with honeybee mortality. However, imidacloprid was aliased with the factor beekeeper, so the earlier shown correlation is possibly a disguised beekeepers effect. A negative effect of imidacloprid in surface water on honeybee colony survival in the Netherlands is therefore not shown in this study. Although it can not be proven that imidacloprid has no influence on honeybee mortality, it seems unlikely that imidacloprid in surface water as a single factor is relevant to the current problem. Possible interactions between imidacloprid and factors that undermine the vitality of colonies are not taken into account in this study.

Do federal farm policies influence surface water quality?

Federal government farm payments authorized by the Farm Bill accounted for 32% of the total U.S. net farm income in 2005. This study uses Census of Agriculture and nitrate-nitrogen (NN) data to ask whether there is a quantifiable relationship between the allocation of these farm payments and indicators of surface water quality using 29 independent watersheds covering 28% of the conterminous U.S. The analysis identifies a significant relationship between increasing government farm payments and: (1) increasing riverine NN concentrations, (2) more expansive fertilizer applications, (3) commodity specialization, and (4) reductions in cropland diversity. These results suggest that federal farm policies could be an important factor affecting water quality, and the authors present a working hypothesis that farm policies influence land use decisions that, in turn, ultimately influence water quality. These farm payments, subsequently, could be used as a potent policy instrument to influence alternative environmental and economic outcomes that protect soil and water resources.

Long-term dynamics of dissolved organic carbon: Implications for drinking water supply

Surface waters are the main source of drinking water in many regions. Increasing organic carbon concentrations are a cause for concern in Nordic countries since both dissolved and particulate organic carbon can transport contaminants and adversely affect drinking water treatment processes. We present a long-term study of dynamics of total (particulate and dissolved) organic carbon (TOC) concentrations in the River Fyris. This river supplies drinking water to approximately 200000 people in Uppsala, Sweden. The River Fyris is a main tributary to Lake Mälaren, which supplies drinking water to approximately 2 million people in the greater Stockholm area. Utilities responsible for drinking water supply in both Uppsala and Stockholm have expressed concerns about possible increases in TOC. We evaluate organic carbon dynamics within the Fyris catchment by calculating areal mass exports using observed TOC concentrations and modeled flows and by modeling dissolved organic carbon (as a proxy for TOC) using the dynamic, process based INCA-C model. Exports of TOC from the catchment ranged from 0.8 to 5.8gm−2year−1 in the period 1995–2010. The variation in annual exports was related to climatic variability which influenced seasonality and amount of runoff. Exports and discharge uncoupled at the end of 2008. A dramatic increase in TOC concentrations was observed in 2009, which gradually declined in 2010–2011. INCA-C successfully reproduced the intra- and inter-annual variation in concentrations during 1996–2008 and 2010–2011 but failed to capture the anomalous increase in 2009. We evaluated a number of hypotheses to explain the anomaly in 2009 TOC values, ultimately none proved satisfactory. We draw two main conclusions: there is at least one unknown or unmeasured process controlling or influencing surface water TOC and INCA-C can be used as part of the decision-making process for current and future use of rivers for drinking water supply.

Charging and discharging behavior in dielectric-coated MEMS electrodes probed by Kelvin probe force microscopy

The charging and discharging behavior of silicon dioxide, silicon nitride and aluminum nitride dielectric coatings on microfabricated aluminum electrodes in response to an applied voltage, thermal treatment, operating environment and monolayer coating have been investigated through Kelvin probe force microscopy (KPFM) techniques. Correlated results from surface potential measurements and finite element simulations demonstrate the existence of capacitive coupling between the KPFM probe tip assembly and the device sample which give rise to as much as 20–40% difference between the applied bias and the measured surface potential. Surface charge mobility on the three material systems has been differentiated focusing on the influence of bulk and surface water and the relevant physicochemical properties. The merits and limitations of proposed schemes for mitigating the effects of dielectric charging, including thermal treatment and monolayer coating, are presented.

Early Holocene large-scale meltwater discharge from Greenland documented by foraminifera and sediment parameters

Records of foraminiferal assemblages combined with lithological properties (grain size, magnetic parameters and XRF data) of marine sediment cores from West Greenland coastal waters and the adjacent Labrador Sea document widespread early Holocene meltwater discharge. This discharge is concluded to originate from large-scale melting of the Greenland Ice Sheet (GIS) having started prior to 8600cal.yrBP and ended at about 7700–7500cal.yrBP, when the GIS margin had withdrawn from the fjords and become mainly land-based. The benthic foraminiferal record from one of the coastal sites mainly reflects West Greenland Current (WGC) subsurface water properties and to a minor degree surface productivity. The most significant feature in this record is an abrupt shift to a higher-productivity regime around ~7700cal.yrBP. We suggest that the cessation of a widespread GIS meltwater discharge at that time favoured an increased influence of (sub)surface water of Atlantic origin and initiation of modern subpolar gyre circulation enabling Labrador Sea deep convection. Further offshore, a record of planktonic foraminiferal assemblages shows an oceanographic change at ca. 9500cal.yrBP, whilst a gradual but marked change in the planktonic foraminiferal assemblage between 8800 and 7000cal.yrBP may be related to a narrowing of the WGC low-salinity surface water belt. The oceanic regime off West Greenland prior to ~7800cal.yrBP was thus characterised by the presence of a permanent and widespread meltwater surface layer, presumably preventing deep convection in this region. Apart from indications of a slight decrease in meltwater discharge by the benthic foraminiferal fauna data, neither of the records show any clear signal of a regionally important 8.2ka event.

THE ENVIRONMENT AND THE UTILIZATION THE STATUSOF THE SUBSIDENCE AREA THE IN XU ZHOU, YAN ZHOU AND HUAINAN AND HUAIBEI REGION OF CHINA

The coal mining subsidence land in East China was mainly distributed in Huanghuaihai Plain such as Kailuan, Huainan, Huaibei, Xuzhou, Pingdingshan, Yanzhou and other coal mining area. At present, the surface subsidence caused by underground mining area could reach 13000 km2, and over half of which was concentrated in the plains, especially Xu Yan, Huainan and Huaibei region. Surface collapse of coal field is one kind of geological disaster with great hazard, which may result from distortion and breakout of overlying strata that lose their support after underground coal beds are excavated in a large area. Due to the little dip angle coal seam, thick sediment loose layer, high phreatic water level on the flat XUYAN, Huainan and Huaibei Plain, and the the collapse land was lower than surface, the different depth and different size of subsidence water ponds were formed. On the influence of precipitation and surface water, XUYAN, Huainan and Huaibei coal mine subsidence showed with the appearance of water-logged area or marshland. With the change of precipitation, topography and geological condition of coal seam, the depth and dimension of the subsidence water area increased gradually, and the arid and seasonal water-logged area were decreasing gradually, and on the contrary, the subsidence flat marshland and the perennial shallow and deep waterlogged area was increasing gradually.

Divergent hydrological responses to 20th century climate change in shallow tundra ponds, western Hudson Bay Lowlands

[1] The hydrological fate of shallow tundra lakes and ponds under conditions of continued warming remains uncertain, but has important implications for wildlife habitat and biogeochemical cycling. Observations of unprecedented pond desiccation, in particular, signify catastrophic loss of aquatic habitat in some Arctic locations. Shallow tundra ponds are a ubiquitous feature in the western Hudson Bay Lowlands (HBL), a region that has undergone intense warming over the past ∼50 years. But it remains unknown how hydrological processes in these ponds have responded. Here, we use cellulose-inferred pond water oxygen isotope records from sediment cores, informed by monitoring of modern pond water isotope compositions during the 2009 and 2010 ice-free seasons, to reconstruct hydrological conditions of four shallow tundra ponds in the western HBL over the past three centuries. Following an interval of relative hydrological stability during the early part of the records, results reveal widely differing hydrological responses to 20th century climate change among the study sites, which is largely dependent on hydrological connectivity of the basins within their respective surrounding peatlands. These findings suggest the 20th century has been characterized by an increasingly dynamic landscape that has variably influenced surface water balance – a factor that is likely to play a key role in determining the future water balance of ponds in this region.