Sample records for lake sediments lake

  1. Radiochronology of lake sediments

    Erten, H.N. [Bilkent Univ., Ankara (Turkey). Dept. of Chemistry


    Sediment cores from Lakes Zurich, Constance, from the Sea of Marmara and from southern Turkey, northern Cyprus and eastern Spain were dated using natural {sup 210}Pb, fallout {sup 137}Cs and cosmic-ray produced {sup 7}Be radionuclides. Constant activity regions in the uppermost sections of sediments from Lake Zurich and the Sea of Marmara were attributed to post-depositional mobility of {sup 210}Pb in the former case and to bioturbation in the latter. A serious discrepancy exists between the {sup 210}Pb dating of Sea of Marmara sediments and those obtained by organic carbon based methods. The elements Zn, Cu, P and Pb were enriched in the upper sections of the sediment cores corresponding to the last 200 years. The increased metallurgical activities as a result of reforms in the Ottoman Army during the 18th century could be the most likely cause. (Author).

  2. Biogeochemistry of Kenyan Rift Valley Lake Sediments

    Grewe, Sina; Kallmeyer, Jens


    The numerous lakes in the Kenyan Rift Valley show strong hydrochemical differences due to their varying geologic settings. There are freshwater lakes with a low alkalinity like Lake Naivasha on the one hand and very salt-rich lakes with high pH values like Lake Logipi on the other. It is known that the underlying lake sediments are influenced by the lake chemistry and by the microorganisms in the sediment. The aim of this work is to provide a biogeochemical characterization of the lake sediments and to use these data to identify the mechanisms that control lake chemistry and to reconstruct the biogeochemical evolution of each lake. The examined rift lakes were Lakes Logipi and Eight in the Suguta Valley, Lakes Baringo and Bogoria south of the valley, as well as Lakes Naivasha, Oloiden, and Sonachi on the Kenyan Dome. The porewater was analysed for different ions and hydrogen sulphide. Additionally, alkalinity and salinity of the lake water were determined as well as the cell numbers in the sediment, using fluorescent microscopy. The results of the porewater analysis show that the overall chemistry differs considerably between the lakes. In some lakes, concentrations of fluoride, chloride, sulphate, and/or hydrogen sulphide show strong concentration gradients with depth, whereas in other lakes the concentrations show only minor variations. Fluoride is present in all lakes; the lowest concentration is found in Lake Oloiden (60 - 90 mg/l), the highest one in Lake Bogoria (1,025 - 1,930 mg/l). The lakes show also large differences in sulphate concentrations. The values vary between 2 mg/l in Lake Baringo and 15,250 mg/l in Lake Eight. In all cores, sulphate concentration does not change significantly with depth; however, there is a distinct peak in each core, raising the question of synchronicity. As expected, chloride concentrations correlate with total salinity. There is no hydrogen sulphide present in the porewater of Lakes Naivasha, Baringo, and Oloiden, whereas in

  3. Lake

    Wien, Carol Anne


    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  4. Mechanisms of Methane Release From Lake Sediments

    Shiba, Jacob


    Methane is a powerful greenhouse gas that can be produced in bottom sediments of lakes and reservoirs and released through ebullition and other properties. Many studies have quantified ebullition rates, however, the detailed mechanisms remain incompletely understood. This study was undertaken to better understand, through in situ and laboratory measurements, the mechanisms of gas ebullition from lake sediment. Four sites on Lake Elsinore, CA with different properties were evaluated through th...

  5. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias


    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences.

  6. Lake-floor sediment texture and composition of a hydrothermally-active, volcanic lake, Lake Rotomahana

    Pittari, A.; Muir, S. L.; Hendy, C. H.


    Young volcanic lakes undergo a transition from rapid, post-eruptive accumulation of volcaniclastic sediment to slower pelagic settling under stable lake conditions, and may also be influenced by sublacustrine hydrothermal systems. Lake Rotomahana is a young (129 year-old), hydrothermally-active, volcanic lake formed after the 1886 Tarawera eruption, and provides a unique insight into the early evolution of volcanic lake systems. Lake-bottom sediment cores, 20-46 cm in length, were taken along a transect across the lake and characterised with respect to stratigraphy, facies characteristics (i.e., grain size, componentry) and pore water silica concentrations. The sediments generally comprise two widespread facies: (i) a lower facies of light grey to grey, very fine lacustrine silt derived from the unconsolidated pyroclastic deposits that mantled the catchment area immediately after the eruption, which were rapidly reworked and redeposited into the lake basin; and (ii) an upper facies of dark, fine-sandy diatomaceous silt, that settled from the pelagic zone of the physically stable lake. Adjacent to sublacustrine hydrothermal vents, the upper dark facies is absent, and the upper part of the light grey to grey silt is replaced by a third localised facies comprised of hydrothermally altered pale yellow to yellowish brown, laminated silt with surface iron-rich encrustations. Microspheres, which are thought to be composed of amorphous silica, although some may be halloysite, have precipitated from pore water onto sediment grains, and are associated with a decrease in pore water silicon concentration. Lake Rotomahana is an example of a recently-stabilised volcanic lake, with respect to sedimentation, that shows signs of early sediment silicification in the presence of hydrothermal activity.

  7. Arsenic mobility in contaminated lake sediments

    Nikolaidis, Nikolaos P.; Dobbs, Gregory M.; Chen, Jing; Lackovic, Jeffrey


    An arsenic contaminated lake sediment near a landfill in Maine was used to characterize the geochemistry of arsenic and assess the influence of environmental conditions on its mobility. A kinetic model was developed to simulate the leaching ability of arsenic in lake sediments under different environmental conditions. The HM1D chemical transport model was used to model the column experiments and determine the rates of arsenic mobility from the sediment. Laboratory studies provided the information to construct a conceptual model to demonstrate the mobility of arsenic in the lake sediment. The leaching ability of arsenic in lake sediments greatly depends on the flow conditions of ground water and the geochemistry of the sediments. Large amounts of arsenic were tightly bound to the sediments. The amount of arsenic leaching out of the sediment to the water column was substantially decreased due to iron/arsenic co-precipitation at the water-sediment interface. Overall, it was found that arsenic greatly accumulated at the ground water/lake interface and it formed insoluble precipitates. - Arsenic accumulates at the ground water/lake interface, where it forms insoluble precipitates.

  8. Detecting Magnetosomes in Freshwater Lakes and Lake Sediments

    Kodama, K. P.; Kim, B.; Kopp, B.; Chen, A. P.


    We will present a summary of the work done to date on detecting magnetosomes in the lake sediments and water column of Lake Ely, a small post-glacial lake in northeastern Pennsylvania. To establish that magnetosomes dominate the magnetic mineralogy of the Lake Ely sediments we sampled the water column every meter down to its maximum depth of 23 m and measured the dissolved oxygen, sulfide, and iron, as well as the ARM of the material filtered from the water. We examined the water samples for magnetotactic bacteria. These results established an increase in the ARM of the filtered material at the oxic-anoxic transition. They also showed that the ARM was carried by magnetosomes produced by magnetotactic bacteria living in the water column at depths from 15-19 m. TEM of magnetic separates collected from the lake sediments show that magnetosomes are transferred to the sediments from the water column and are a significant fraction of the magnetic minerals in the sediments. We used a variety of mineral magnetic techniques to magnetically characterize the magnetosomes in the lake sediments. The delta-delta ratio test of low temperature behavior at the Verwey transition (Moskowitz et al., 1993) gave values of 1.2 to 1.5, lower than the theoretically predicted level of 2 for magnetosomes, but a numeric unmixing technique could resolve higher delta-delta ratios in the dark organic-rich layers in the sediments where magnetosomes were more prevalent. ARM/SIRM ratios of 0.15 to 0.35 with Raf values (the crossover of an IRM acquisition curve versus its alternating field demagnetization curve) of 0.45 to 0.5 are consistent with the presence of magnetosomes in the sediments, the water column, and in a sediment trap located at the bottom of the lake. IRM and ARM acquisition modeling of samples collected from a 160 cm piston core revealed two components of magnetization with coercivities of about 25 mT and 65 mT that are identified as Egli's (2004) biogenic soft (BS) and biogenic

  9. Folsom Lake 2005 Sedimentation Survey

    US Bureau of Reclamation, Department of the Interior — The Bureau of Reclamation (Reclamation) surveyed Folsom Lake in the fall of 2005 via an interagency agreement with the U.S. Army Corps of Engineers (Corps of...


    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  11. Chronology of Lake El'gygytgyn sediments

    N. R. Nowaczyk


    Full Text Available A 318 m long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chrono-stratigraphic methods. The 12 km wide lake is sited in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the Earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1.

  12. Sediment Remediation for Ecosystem in Eutrophic Lakes

    Y. Amano


    Full Text Available The remediation method — namely, a hybrid system combined with DAF and CRM — is studied in this paper for the size reduction of aqua-ecological circulation and for the elution control in lakes. Results show that two effects on water quality purification, the sediment washout effect and the elution control effect, can be induced by this system, and the biota inhabiting the lake is therefore shifted into an oligotrophic aspect, from blue algae to green algae and/or diatoms.

  13. Seasonal variations in pore water and sediment geochemistry of littoral lake sediments (Asylum Lake, MI, USA)

    Miller Douglas; Haas Johnson R; Koretsky Carla M; Ndenga Noah T


    Abstract Background Seasonal changes in pore water and sediment redox geochemistry have been observed in many near-surface sediments. Such changes have the potential to strongly influence trace metal distribution and thus create seasonal fluctuations in metal mobility and bioavailability. Results Seasonal trends in pore water and sediment geochemistry are assessed in the upper 50 cm of littoral kettle lake sediments. Pore waters are always redox stratified, with the least compressed redox str...

  14. Microbial diversity in lake sediments detected by PCR-DGGE

    Xinqing ZHAO; Liuyan YANG; Can CHEN; Lin XIAO; Lijuan JIANG; Zhe MA; Haowei ZHU; Zhenyang YU; Daqiang YIN


    In this study,PCR-denaturing gradient gel electrophoresis (DGGE) was applied to analyze the microbial communities in lake sediments from Lake Xuanwu,Lake Mochou in Nanjing and Lake Taihu in Wuxi.Sediment samples from seven locations in three lakes were collected and their genomic DNAs were extracted.The DNA yields of the sediments of Lake Xuanwu and Lake Mochou were high (10 μg/g),while that of sediments in Lake Taihu was relatively low.After DNA purification,the 16S rDNA genes (V3 to V5 region) were amplified and the amplified DNA fragments were separated by parallel DGGE.The DGGE profiles showed that there were five common bands in all the lake sediment samples indicating that there were similarities among the populations of microorganisms in all the lake sediments.The DGGE profiles of Lake Xuanwu and Lake Mochou were similar and about 20 types of micro-organisms were identified in the sediment samples of both lakes.These results suggest that the sediment samples of these two city lakes (Xuanwu,Mochou) have similar microbial communities.However,the DGGE profiles of sediment samples in Lake Taihu were significantly differ-ent from these two lakes.Furthermore,the DGGE pro-files of sediment samples in different locations in Lake Taihu were also different,suggesting that the microbial communities in Lake Taihu are more diversified than those in Lake Xuanwu and Lake Mochou.The differences in microbial diversity may be caused by the different environmental conditions,such as redox potential,pH,and the concentrations of organic matters.Seven major bands of 16S rDNA genes fragments from the DGGE profiles of sediment samples were further re-amplified and sequenced.The results of sequencing analysis indicate that five sequences shared 99%-100% homology with known sequences (Bacillus and Brevibacillus,uncultured bacteria),while the other two sequences shared 93%-96% homology with known sequences (Acinetobacter,and Bacillus).The study shows that the PCR-DGGE tech

  15. Lake Sediments from Dianchi Lake:A Phosphorus Sink or Source?

    GAO Li; YANG Hao; ZHOU Jian-Min; Lü Jun-Jie


    Dianchi Lake is a highly eutrophic lake in southwestern China where phosphorus (P) is the limiting element for eutrophication and where lake sediments play an important role in the P cycle. One hundred and eighteen sites were sampled throughout Dianchi Lake in 2002 to investigate the P loading of the lake sediments, while fresh surface sediments were studied in the laboratory to clarify its role for phosphorus. The results showed that concentrations of total phosphorus (TP) in sediments were very high, with a maximum value of 6.66 g kg-1, and decreased with sediment depth. P adsorption on surface sediments was rapid with adsorption amounts higher in acidic than in alkaline conditions. The release experiments showed that P release increased as pH rose from 7.0 to 10.5. Additionally, compared with aerobic conditions, P release was much higher under anaerobic conditions, especially with low P content in the lake water. At present, the sediments in Dianchi Lake still function as a sink for phosphorus at high P levels in lake water. However, if the external P load was reduced and P content in lake water became low, the sediment would have a large potential for P release under anaerobic conditions.

  16. Palaeoclimatic Indicators of China's Quaternary Saline Lake Sediments and Hydrochemistry


    In this paper the authors classify saline lake sediments into the cold, warm and eurythermal phases, reveal the consistency between the zoning of hydrochemical types of modern saline lake water and climatic zoning and give climatic parameters under the conditions of typical cold phase (mirabilite and natron), warm phase (thenardite) and slightly warm phase (bloedite) saline lake deposition.

  17. Tapped lakes as sediment traps in an Arctic delta

    Walker, J.; McGraw, M.


    Lakes within the Colville River delta in northern Alaska, USA, vary in size from small ponds created by ice-wedge growth to thaw lakes that are as much as three kilometres long and ten metres deep. As the river migrates, lake edges are breached and the lakes are drained. Such lake tapping is aided by permafrost thaw and ice wedge melt and, in the case of the larger lakes, by wave action within them. Once a lake is tapped, it drains rapidly creating a deep scour hole at its entrance and from then on it is subject to the varying stages and discharge of the river. During flooding, when the river is transporting its largest amount of sediment, the tapped lakes become settling basins and rapidly fill. The Colville River delta has lakes in all stages from freshly breached to those that are now being destroyed by channel migration.

  18. Modern non-pollen palynomorphs from East African Lake sediments

    Gelorini, V.; Verbeken, A.; van Geel, B.; Cocquyt, C.; Verschuren, D.


    This paper presents an illustrated guide to the identification of non-pollen palynomorphs (NPPs) preserved in lake-sediment archives from equatorial East Africa. Modern NPPs were recovered from recently deposited surface sediment in 20 small crater lakes in western Uganda, located along environmenta

  19. Enrichment of metals in the surface sediments of Sapanca Lake

    Bakan, G.; Balkas, T.I.


    A comprehensive lake sediment study was performed on the Sapanca Lake of Turkey in which certain metal analyses were conducted using inductively coupled plasma atomic emission spectroscopy. The purpose of the study was to find the enrichment of metals in the surface sediments of Sapanca Lake. A method, namely, the index of geoaccumulation, was used to define the degree of anthropogenic pollution in the Sapanca Lake basin. Results of the geoaccumulation index indicate that only enrichments of trace metals, cadmium, and lead are found.

  20. Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China.

    Yang, Yuyi; Cao, Xinhua; Lin, Hui; Wang, Jun


    Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg(-1) (dry weight (dw)) with mean value of 278.21 μg kg(-1) dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg(-1) dw, mean value of 195.70 μg kg(-1) dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p  tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.

  1. Analysis of elements in lake sediment samples by PIXE spectrometry

    Chelarescu, E. D.; Radulescu, C.; Stihi, C.; Bretcan, P.; Tanislav, D.; Dulama, I. D.; Stirbescu, R. M.; Teodorescu, S.; Bucurica, I. A.; Andrei, R.; Morarescu, C.


    This work aims to determine the concentrations of several elements (e.g. Pb, Ni, Zn, Mn, Cr, and Fe) from lake sediments, in order to characterize their origin and evolution. Particle Induced X-ray Emission (PIXE) technique using the 3 MV Tandetron™ particle accelerator from National Institute for R&D in Physics and Nuclear Engineering ;Horia Hulubei; (IFIN-HH), Magurele-Bucharest, Romania, was applied. Sediment cores from different salt lakes from Romania (i.e. Amara Lake, Caineni Lake, and Movila Miresii Lake) were collected, in August 2015. The content of Pb, Cr, Mn, Fe, and Ni from sediment samples show similarities with other data presented in literature and international regulation. The Zn was the only element with a higher content in all samples (e.g. maximum 401.7-517.3 mg/kg d.w.).

  2. Varves in lake sediments - a review

    Zolitschka, Bernd; Francus, Pierre; Ojala, Antti E. K.; Schimmelmann, Arndt


    Downcore counting of laminations in varved sediments offers a direct and incremental dating technique for high-resolution climatic and environmental archives with at least annual and sometimes even seasonal resolution. The pioneering definition of varves by De Geer (1912) had been restricted to rhythmically deposited proglacial clays. One century later the meaning of 'varve' has been expanded to include all annually deposited laminae in terrestrial and marine settings. Under favourable basin configurations and environmental conditions, limnic varves are formed due to seasonality of depositional processes from the lake's water column and/or transport from the catchment area. Subsequent to deposition of topmost laminae, the physical preservation of the accumulating varved sequence requires the sustained absence of sediment mixing, for example via wave action or macrobenthic bioturbation. Individual (sub)laminae in varved lake sediments typically express contrasting colours, always differ in terms of their organic, chemical and/or mineralogical compositions, and often also differ with regard to grain-size. Various predominating climatic and depositional conditions may result in clastic, biogenic or endogenic (incl. evaporitic) varved sediments and their mixtures. To reliably establish a varve chronology, the annual character of laminations needs to be determined and verified in a multidisciplinary fashion. Sources and influences of possible errors in varve chronologies are best determined and constrained by repeated varve counts, and by including radioisotopes and correlation with historically documented events. A well-established varve chronology greatly enhances the scientific value of laminated limnic archives by securely anchoring the wealth of multi-proxy palaeoenvironmental information in the form of time-series for multidisciplinary investigations. Applications of varved records are discussed with special reference to advances since the 1980s. These span fields

  3. Monitoring climate signal transfer into the varved lake sediments of Lake Czechowskie, Poland

    Groß-Schmölders, Miriam; Ott, Florian; Brykała, Dariusz; Gierszewski, Piotr; Kaszubski, Michał; Kienel, Ulrike; Brauer, Achim


    In 2012 we started a monitoring program at Lake Czechowskie, Poland, because the lake comprises a long Holocene time series of calcite varves until recent times. The aim of the program is to understand how environmental and climatic conditions influence the hydrological conditions and, ultimately, the sediment deposition processes of the lake. Lake Czechowskie is located in the north of Poland in the Pomeranian Lake District and is part of the national park Tuchola Forest. The landscape and the lake is formed by the glacier retreat after the last glaciation (Weichselian). Lake Czechowskie is a typical hardwater lake and has a length of 1.4 km, an average width of 600 m and a lake surface area of ca 4 km. The maximum depth of 32 m is reached in a rather small hollow in the eastern part of the lake. Two different types of sediment traps provide sediment samples with monthly resolution from different water depths (12m, 26m). In addition, hydrological data including water temperature in different depths, water inflow, throughflow and outflow and the depth of visibility are measured. These data allow to describe strength and duration of lake mixing in spring and autumn and its influence on sedimentation. The sediment samples were analyzed with respect to their dry weight (used to calculate mean daily sediment flux), their inorganic and organic carbon contents, the stable C- and O-isotopes of organic matter and calcite as well as N-isotopes of organic matter. For selected samples dominant diatom taxa are determined. Our first results demonstrate the strong influence of the long winter with ice cover until April in 2013 on the sedimentation. A rapid warming in only 9 days starting on April 9th from -0,3 C° to 15,2 C° resulted in fast ice break-up and a short but intensive lake mixing. In consequence of this short mixing period a strong algal bloom especially of Fragilaria and Crysophycea commenced in April and had its maximum in May. This bloom further induced biogenic

  4. Chemical analysis of sediments from Lake Champlain

    US Fish and Wildlife Service, Department of the Interior — This report provides the results of a study done on Lake Champlain to evaluate the level of environmental contaminants at specific sites impacted by human...

  5. Jellyfish Lake, Palau: early diagenesis of organic matter in sediments of an anoxic marine lake

    Orem, W.H.; Burnett, W.C.; Landing, W.M.; Lyons, W.B.; Showers, W.


    The major postdepositional change in the sedimentary organic matter is carbohydrate biodegradation. Lignin and aliphatic substances are preserved in the sediments. Dissolved organic matter in pore waters is primarily composed of carbohydrates, reflecting the degradation of sedimentary carbohydrates. Rate constants for organic carbon degradation and sulfate reduction in sediments of the lake are about 10?? lower than in other anoxic sediments. This may reflect the vascular plant source and partly degraded nature of the organic matter reaching the sediments of the lake. -from Authors

  6. Geovisualization of Mercury Contamination in Lake St. Clair Sediments

    K. Wayne Forsythe


    Full Text Available The Laurentian Great Lakes of North America contain approximately 20% of the earth’s fresh water. Smaller lakes, rivers and channels connect the lakes to the St. Lawrence Seaway, creating an interconnected freshwater and marine ecosystem. The largest delta system in the Great Lakes is located in the northeastern portion of Lake St. Clair. This article focuses on the geovisualization of total mercury pollution from sediment samples that were collected in 1970, 1974 and 2001. To assess contamination patterns, dot maps were created and compared with surfaces that were generated using the kriging spatial interpolation technique. Bathymetry data were utilized in geovisualization procedures to develop three-dimensional representations of the contaminant surfaces. Lake St. Clair generally has higher levels of contamination in deeper parts of the lake, in the dredged shipping route through the lake and in proximity to the main outflow channels through the St. Clair delta. Mercury pollution levels were well above the Probable Effect Level in large portions of the lake in both 1970 and 1974. Lower contaminant concentrations were observed in the 2001 data. Lake-wide spatial distributions are discernable using the kriging technique; however, they are much more apparent when they are geovisualized using bathymetry data.

  7. [Limnology of high mountain tropical lake, in Ecuador: characteristics of sediments and rate of sedimentation].

    Gunkel, Günter


    Equatorial high mountain lakes are a special type of lake occurring mainly in the South American Andes as well as in Central Africa and Asia. They occur at altitudes of a few thousand meters above sea level and are cold-water lakes (limnological study was therefore undertaken at Lake San Pablo, Ecuador, to analyze the basic limnological processes of the lake, which has a tendency for eutrophication. Sediment quality of San Pablo Lake is given under consideration of horizontal and vertical distribution using sediment cores. Significance of sediments for eutrophication process of lakes is demonstrated using phosphorus concentration of sediments as well as the phosphorus retention capacity of the sediments by ratio Fe/P. Dating of the sediments is done using 137Cs and 210Pb, but the activity of 137Cs in the sediment was very low nearly at the detection level. Sedimentation rate is determined to be 3.5 mm/year and the sediment cores represent about 110 years. P concentration of the sediments is high (approximately 5 g/kg dry substance), and P retention capacity by Fe is insufficient (Fe/P = 4). The sediment quality did not change significantly during the past decades, and the trophic state of San Pablo Lake was already less or more eutrophic 110 years ago. The contamination of the lake sediments by heavy metals is insignificant.

  8. Magnetic properties of lake sediments from Lake Chalco, central Mexico, and their palaeoenvironmental implications

    Ortega Guerrero, Beatriz; Thompson, Roy; Urrutia Fucugauchi, Jaime


    Lake Chalco (99.0°W, 19.5°N) in the Basin of Mexico, was formed during the Pleistocene after the emplacement of the Chichinautzin volcanic field that closed the former drainage system. The lake sediment record has been influenced by a number of factors, including glacial-interglacial cycles, local volcanism, erosion of soils and anthropogenic disturbances. The magnetic properties of the lake sediments and the associated tephra layers of the last 16500 yr have been studied. It is found that the magnetic properties of the Lake Chalco sediments are very distinctive. Magnetic concentration varies by a factor of 1000 and magnetic stability also varies over an extremely wide range. The predominant magnetic mineral is titanomagnetite in addition to an imperfect antiferromagnetic phase, possibly goethite. An unusually large range of coercivities is found in certain of the tephras. Down-core variations in magnetic properties closely follow climatic/environmental changes previously established by other proxy methods. The late Pleistocene and late Holocene lake sediments display a higher concentration of magnetic minerals than the early-middle Holocene sediments. In the non-volcanic sediments, fluctuations in the magnetic concentration reflect changes in both the intensity of erosion, as represented by ferrimagnetic and paramagnetic minerals, and by the maturing of soils, as represented by geothite.

  9. Polycyclic aromatic hydrocarbons in lake sediments from the High Tatras

    Drooge, Barend L. van, E-mail: [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona, Catalonia (Spain); Lopez, Jordi; Fernandez, Pilar; Grimalt, Joan O. [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona, Catalonia (Spain); Stuchlik, Evzen [Department of Hydrology, Charles University, Vinicna 7, 12044 Prague (Czech Republic)


    European alpine lake systems are used as indicators of air quality over the continent. Preliminary data showed high polycyclic aromatic hydrocarbons (PAH) loads in the High Tatras (Eastern Europe) in comparison to other mountain regions. Here, insight on the spatial distribution of PAH is provided from analysis of top-core sediments of 27 alpine lakes distributed along the High Tatras. Top-core sediment concentrations were higher than those in deep-cores, and they were higher than those observed in other European high mountain regions. The PAH profiles were uniform and comparable to those observed in aerosols and snow, indicating that atmospheric deposition was the predominant PAH input pathway to the lakes. Good agreement between estimated atmospheric deposition and sedimentation fluxes was observed. However, in several lakes in the western range higher sediment fluxes may correspond to higher PAH depositions levels. The higher concentrations may also reflect inputs from potential emission source areas. - Highlights: > Sedimentary PAH loads in alpine lakes from High Tatras (Eastern Europe) were higher than in other European mountain regions. > Sediments PAH profiles comparable to aerosol and snow deposition profiles. > Positive correlation between PAH atmospheric deposition and sedimentary fluxes. - High sedimentary PAH loads were observed in alpine lakes in the High Tatras (Eastern Europe) which are related to high PAH atmospheric deposition fluxes.

  10. The Magnetic Properties of Indonesian Lake Sediment: A Case Study of a Tectonic Lake in South Sulawesi and Maar Lakes in East Java

    Gerald Tamuntuan


    Full Text Available Magnetic properties of sediments from two different environmental settings in Indonesia have been studied using rock magnetic methods and scanning electron microscopy (SEM. In the first setting, magnetic measurements were conducted on core sediments from two maar lakes in East Java (Lakes Lading and Bedali that represent very confined environments where sediments are derived mainly from rocks and soils within the craters. In the second setting, similar measurements were obtained on core sediment from Lake Matano, a cryptodepression lake in tectonically active South Sulawesi where the area around the lake is dominated by highly magnetic lateritic soils. The results show that the predominant magnetic mineralogy in sediments from Lakes Lading, Bedali, as well as Matano is pseudo-single domain (PSD magnetite (Fe3O4. Compared to that of Lake Matano, the maar lake sediments of Lakes Lading and Bedali have higher magnetic susceptibility as well as high intensity of ARM and SIRM. Variations in magnetic susceptibility in all core sediments are controlled mainly by the concentration of magnetic minerals. The homogeneity of magnetic minerals in these three lakes sediment provides an excellent setting for interpreting paleoclimatic signals as they will be recorded as anomalies of magnetic susceptibility.

  11. Human land uses enhance sediment denitrification and N2O production in Yangtze lakes primarily by influencing lake water quality

    W. Liu


    Full Text Available Sediment denitrification in lakes alleviates the effects of eutrophication through removal of nitrogen to the atmosphere as N2O and N2. However, N2O contributes notably to the greenhouse effect and global warming. Human lands uses (e.g., agricultural and urban areas strongly affect lake water quality and sediment characteristics, which, in turn, may regulate lake sediment denitrification and N2O production. In this study, we investigated sediment denitrification and N2O production and their relationships to within-lake variables and watershed land uses in 20 lakes from the Yangtze River basin in China. The results indicated that both lake water quality and sediment characteristics were significantly influenced by watershed land uses. Increased background denitrification rate would result in increased N2O production rate. Background denitrification and N2O production rates were positively related to water nitrogen concentrations but were not significantly correlated with sediment characteristics and plant community structure. A significant positive relationship was observed between background denitrification rate and percentage of human-dominated land uses (HDL in watersheds. Structural equation modelling revealed that the indirect effects of HDL on sediment denitrification and N2O production in Yangtze lakes were mediated primarily through lake water quality. Our findings also suggest that although sediments in Yangtze lakes can remove large quantities of nitrogen through denitrification, they may also be an important source of N2O, especially in lakes with high nitrogen content.

  12. Phosphorus in sediment in the Kent Park Lake watershed, Johnson County, Iowa, 2014–15

    Kalkhoff, Stephen J.


    Phosphorus data were collected from the Kent Park Lake watershed in Johnson County, Iowa, in 2014 and 2015 to obtain information to assist in the management of the water quality in the lake. Phosphorus concentrations were measured for sediment from several ponds in the watershed and sediment deposited in the lake. The first set of samples was collected in 2014 to understand phosphorus in several potential sources to the lake and the spatial variability in lake sediments. Phosphorus concentrations ranged from 68 to 380 milligrams per kilogram in lake sediment and from 57 to 220 milligrams per kilogram in sedimentation and dredge spoil ponds. Additional samples were collected in 2015 to determine how phosphorus concentrations vary with depth in the lake sediment. Phosphorus concentrations generally decreased with increasing depth within the lake sediment. In 2015, total phosphorus concentrations in lake sediment ranged from 50 to 340 milligrams per kilogram.

  13. Seasonal variations in pore water and sediment geochemistry of littoral lake sediments (Asylum Lake, MI, USA

    Miller Douglas


    Full Text Available Abstract Background Seasonal changes in pore water and sediment redox geochemistry have been observed in many near-surface sediments. Such changes have the potential to strongly influence trace metal distribution and thus create seasonal fluctuations in metal mobility and bioavailability. Results Seasonal trends in pore water and sediment geochemistry are assessed in the upper 50 cm of littoral kettle lake sediments. Pore waters are always redox stratified, with the least compressed redox stratification observed during fall and the most compressed redox stratification observed during summer. A 2-step sequential sediment extraction yields much more Fe in the first step, targeted at amorphous Fe(III (hydroxides (AEF, then in the second step, which targets Fe(II monosulfides. Fe extracted in the second step is relatively invariant with depth or season. In contrast, AEF decreases with sediment depth, and is seasonally variable, in agreement with changes in redox stratification inferred from pore water profiles. A 5-step Tessier extraction scheme was used to assess metal association with operationally-defined exchangeable, carbonate, iron and manganese oxide (FMO, organic/sulfide and microwave-digestible residual fractions in cores collected during winter and spring. Distribution of metals in these two seasons is similar. Co, As, Cd, and U concentrations approach detection limits. Fe, Cu and Pb are mostly associated with the organics/sulfides fraction. Cr and Zn are mostly associated with FMO. Mn is primarily associated with carbonates, and Co is nearly equally distributed between the FMO and organics/sulfide fractions. Conclusion This study clearly demonstrates that near-surface lake sediment pore water redox stratification and associated solid phase geochemistry vary significantly with season. This has important ramifications for seasonal changes in the bioavailability and mobility of trace elements. Without rate measurements, it is not possible to

  14. /sup 137/Cs radioactive dating of Lake Ontario sediment cores

    Ward, T.E.; Breeden, J.; Komisarcik, K.; Porter, R.; Czuczwa, J.; Kaminski, R.; McVeety, B.D.


    The distribution of /sup 137/Cs in sediment cores from Lake Ontario provides estimates of the sediment accumulation rates. Geochronology with /sup 210/Pb dating and distribution of Ambrosia (ragweed) pollen compare well with /sup 137/Cs dating. These methods can determine with precision, changes in sedimentation occurring over the past 100 years or so. Typical sedimentation rates of 0.18-0.36 cm/yr were measured. 16 refs., 3 figs., 2 tabs.

  15. The evolution and distribution of methane in Lake Champlain sediments

    Thibodeau, P.M. (Univ. of Vermont, Burlington, VT (United States). Dept. of Geology)


    Regions of Lake Champlain sediments are acoustically impenetrable to the energy emitted from high resolution, low energy sub-bottom seismic profiling apparatus. This anomolous behavior is caused by the presence of interstitial methane gas which absorbs the wave energy and thus prevents the formation of well-defined seismic boundaries. Through gas chromatographic and carbon isotope analyses, the methane gas contained in the recent sediments of Lake Champlain has been demonstrated to be biogenic in origin. The production of biogenic methane occurs as a result of a series of coupled oxidation-reduction reactions occurring within the upper two meters beneath the sediment-water interface.

  16. In situ sampling of interstitial water from lake sediments

    Brinkman, Albertus G.; van Raaphorst, Wim; Lijklema, Lambertus


    A sampler with a relatively high resolution has been developed, which allows interstitial water to be obtained from lake sediments at well defined depths, without serious disturbance of sediment structure. Oxidation effects are excluded. Sampling time is in the order of a day. Installation requires

  17. The Stratification Analysis of Sediment Data for Lake Michigan

    This research paper describes the development of spatial statistical tools that are applied to investigate the spatial trends of sediment data sets for nutrients and carbon in Lake Michigan. All of the sediment data utilized in the present study was collected over a two year per...

  18. Sediment processes and mercury transport in a frozen freshwater fluvial lake (Lake St. Louis, QC, Canada).

    Canário, João; Poissant, Laurier; O'Driscoll, Nelson; Vale, Carlos; Pilote, Martin; Lean, David


    An open-bottom and a closed-bottom mesocosm were developed to investigate the release of mercury from sediments to the water column in a frozen freshwater lake. The mesoscosms were deployed in a hole in the ice and particulate mercury (Hg(P)) and total dissolved mercury (TDHg) were measured in sediments and in water column vertical profiles. In addition, dissolved gaseous mercury (DGM) in water and mercury water/airflux were quantified. Concentrations of TDHg, DGM, and mercury flux were all higher in the open-bottom mesocosm than in the closed-bottom mesocosm. In this paper we focus on the molecular diffusion of mercury from the sediment in comparison with the TDHg accumulation in the water column. We conclude that the molecular diffusion and sediment resuspension play a minor role in mercury release from sediments suggesting that solute release during ebullition is an important transport process for mercury in the lake.

  19. Sediment characteristics and wind-induced sediment dynamics in shallow Lake Markermeer, the Netherlands

    Kelderman, P.; Ang'weya, R.O.; De Rozari, P.; Vijverberg, T.


    In 2007/08, a study was undertaken on the sediment dynamics in shallow Lake Markermeer (the Netherlands). Firstly, sediment characteristics were determined at 49 sites in the lake. Parameters such as median grain size and loss on ignition showed a spatial as well as water depth related pattern, indi

  20. Dating recent lake sediments using spheroidal carbonaceous particle (SCP)

    WU Yanhong; WANG Sumin; XIA Weilan; LIU Jian


    Dating lake sediment using sedimentary event is the supplement and calibration to traditional dating by radionuclide such as 210Pb and 137Cs. Based on the change of spheroidal carbonaceous particle (SCP) concentration, the age sequence of lake sediments can be deduced. It is one of the dating methods using sedimentary event. SCP is formed from combustion of fossil fuel at high temperature up to 1750℃ and at a rate of heating of approaching 104 ℃/s. It can be dispersed to several hundred kilometers away from its source and deposited with precipitation or dryly deposited, and kept in sediments. Compared with Cs or Pb, there is no evidence for SCP that it decays in lake sediments and is un-removable once stored except by physical disturbance because it is mainly composed of element carbon. Handy method to extract, identify and calculate has been developed. Although fossil fuel has been used early in China, combustion at high temperature started later since emergence of electricity generation. The productivity of SCP is positively related with the generated thermal power, which is reflected as the SCP concentration in lake sediments increases with the increase of generated thermal power. Therefore, reliable sediment markers from the start of the SCP record and the remarkable variation can be used for dating purpose. In China, electricity industry started from the 1950s, and rapid increase of generated power took place since 1978. Based on these time markers, SCP time sequences of lake sediment cores LH and LL-4 from Longgan Lake, the middle reach of the Yangtze River, have been established, which is comparable with the results from 137Cs and 210Pb, and has eliminated the errors of dating using 137Cs and 210Pb.

  1. Modern processes of sediment formation in Lake Towuti, Indonesia, as derived from the composition of lake surface sediments

    Hasberg, Ascelina; Melles, Martin; Morlock, Marina; Vogel, Hendrik; Russel, James M.; Bijaksana, Satria


    In summer 2015, a drilling operation funded by the International Continental Scientific Drilling Program (ICDP) was conducted at Lake Towuti (2.75°S, 121.5°E), the largest tectonically formed lake (surface area: 561 km²) of the Republic Indonesia. The Towuti Drilling Project (TDP) recovered more than 1000 meters of sediment core from three sites. At all three sites replicate cores down to 133, 154, and 174 m below lake floor have penetrated the entire lake sediment record, which is expected to comprise the past ca. 650.000 years continuously. Lake Towutís sediment record thus can provide unique information for instance concerning the climatic and environmental history in the Indo-Pacific-Warm-Pool (IPWP) and concerning the evolutionary biology in SE Asia. For a better understanding of the palaeoenvironmental proxies to be analyzed on the drill cores, the modern processes of sediment formation in the lake and in its catchment - under known environmental conditions - were investigated on a set of 84 lake sediment surface samples. Sampling was conducted by grab sampler (UWITEC Corp., Austria) in a grid of 1 to 4 km resolution that covers the entire lake. The samples were analyzed for inorganic geochemical composition (XRF powder scans and ICP-MS), magnetic susceptibility (Kappabridge), grain-size distribution (laser scanner), biogenic components (smear-slide analyses), biogenic silica contents (leaching), and carbonate, total organic carbon (TOC), nitrogen (TN), and sulfur (TS) concentrations (elemental analyzer). The sediments close to the lake shores and in front of the major river inlets are characterized by mean grain sizes coarser than average and high magnetic susceptibilities presented by high ratios of Cr, Ni, Co, and Zr. This reflects higher energies due to wave action and fluvial sediment supply, as well as the occurrence of magnetic minerals particularly in the sand and gravel fractions of the sediments. In regions of deeper waters and more distal to

  2. Chemical composition of the sediment from Lake 20 (Antarctica

    Daria ROSSI


    Full Text Available Lake 20 (19,000 m2 is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention of using this information to contribute to a better understanding of the processes involved in the long range transport of pollutants and their role in global changes. A sediment core from Lake 20 (Antarctica, 18 cm long, was collected in 1994, sliced into 2 cm sections and analysed using X Ray fluorescence spectrometry for 17 elements (Si, Al, Ca, K, Fe, Mg, Ti, S, P, Pb, Zn, Cu, Ni, Mn, Cr, Na, Cl, by CHN Elemental Analyser for C and N, by Flameless Atomic Absorption Spectrometry for As, and by Cold Vapour Atomic Absorption Spectrometry for Hg. The chemical composition of the sediments is consistent with the known geochemical characteristics of the drainage basin. While the chemical analyses reveal that sedimentation in Lake 20 has changed through time, the variations along the core are most probably related to the climatic evolution of the area, to the consequent changes in weathering processes, and possibly to an increase in the primary productivity of the lake, rather than to anthropogenic influences on the biogeochemical cycles of the elements.

  3. Organic matter degradation in Lake Baikal - a sediment trap study

    Schubert, Carsten J.; Niggemann, Jutta; Lomstein, Bente Aagaard

    Lake Baikal offers a unique opportunity to study water column processes in a freshwater system with conditions similar to oceanic systems, e. g. great water depth and oxygenated water column. Investigations on sediment trap material provide information on the early stages of organic matter...... and composition of amino acids and fatty acids. The extent of organic matter degradation in the water column of Lake Baikal is reflected in the fluxes of total organic carbon, chlorins, amino acids, and fatty acids at different water depths. In line with earlier studies in marine systems, the labile compounds......, and the Fatty Acid Index [2]. All indicators showed consistent trends, indicating that the diagenetic stage of the sediment trap material increased with increasing water depth. This study of sediment trap material from Lake Baikal provided interesting insights in organic matter degradation in this unique...

  4. Small ecosystem engineers as important regulators of lake's sediment respiration.

    Baranov, Victor; Lewandowski, Joerg; Krause, Stefan; Romeijn, Paul


    Although shallow lakes are covering only about 1.5% of the land surface of the Earth, they are responsible for sequestration of carbon amounts similar or even larger than those sequestered in all marine sediments. One of the most important drivers of the carbon sequestration in lakes is sediment respiration. Especially in shallow lakes, bioturbation, i.e. the biogenic reworking of the sediment matrix and the transport of fluids within the sediment, severely impacts on sediment respiration. Widespread freshwater bioturbators such as chironomid larvae (Diptera, Chironomidae) are building tubes in the sediment and actively pump water through their burrows (ventilation). In the present work we study how different organism densities and temperatures (5-30°C) impact on respiration rates. In a microcosm experiment the bioreactive resazurin/resorufin smart tracer system was applied for quantifying the impacts of different densities of Chironomidae (Diptera) larvae (0, 1000, 2000 larvae/m2) on sediment respiration. Tracer transformation rates (and sediment respiration) were correlated with larval densities with highest transformation rates occurring in microcosms with highest larval densities. Respiration differences between defaunated sediment and sediment with 1000 and 2000 larvae per m2 was insignificant at 5 °C, and was progressively increasing with rising temperatures. At 30 °C respiration rates of sediment with 2000 larvae per m2 was 4.8 times higher than those of defaunated sediment. We interpret this as an effect of temperature on larval metabolic and locomotory activity. Furthermore, bacterial communities are benefiting from the combination of the high water temperatures and bioirrigation as bacterial community are able to maintain high metabolic rates due to oxygen supplied by bioirrigation. In the context of global climate change that means that chironomid ecosystem engineering activity will have a profound and increasing impact on lake sediment respiration

  5. Lake sediment records on climate change and human activities in the Xingyun Lake catchment, SW China.

    Zhang, Wenxiang; Ming, Qingzhong; Shi, Zhengtao; Chen, Guangjie; Niu, Jie; Lei, Guoliang; Chang, Fengqin; Zhang, Hucai


    Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC), total nitrogen (TN), δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS) and CaCO3 content), as well as accelerator mass spectrometry (AMS) 14C datings, four major climatic stages during the Holocene have been identified in Xingyun's catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP) were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

  6. Lake sediment records on climate change and human activities in the Xingyun Lake catchment, SW China.

    Wenxiang Zhang

    Full Text Available Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC, total nitrogen (TN, δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS and CaCO3 content, as well as accelerator mass spectrometry (AMS 14C datings, four major climatic stages during the Holocene have been identified in Xingyun's catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

  7. Last millenium environmental changes in Lake Bertrand sediments, Chilean Patagonia

    Sacré, V.; Fagel, N.; Schmidt, S.; Alvarez, D.; Araneda, A.; Urrutia, R.


    Our study focuses on a multiproxy analysis of sedimentary records from Lago Bertrand (area 50 km2; 227 masl; 46°55'S 72°50'W). Three cores were retrieved during fieldtrips in 2009 and 2011 with an Uwitec gravity corer. One core was collected in the main lake (LBt09, 102 cm) and two others in a lateral extension (LBb11-A, 162 cm and LBb11-B, 156 cm). Data 210Pb and 137Cs give average sedimentation rates of 2 mm/yr for the upper core section from the main lake, allowing a decennial resolution. Our aim is to document the climatic variability during the last millennium in Northern Patagonia and its impact on the environment. Lago Bertrand is separated from a pro-glacial lake (Lago Plomo) by a morainic barrier. The sediments of this lake are mainly composed of clayed silts and very few sandy silts. In the cores from the Eastern branch of Lago Bertrand, X-ray radiographies and magnetic susceptibility profiles evidence well-defined pluri-millimetric laminations with organic-rich layers, especially in the central core section. In the main lake, X-ray radiographies show diffuse pluri-millimetric laminations while magnetic susceptibility profiles do not confirm it. The sediments of the main lake appear more homogeneous with less organic-rich layers. They are characterized by low C/N ratio (10), supporting an important aquatic productivity; high inorganic content (90-95% of the bulk sediment); two peaks in the biological silica profile; and abundant diatoms (50-100 µm). According to the age model, the changes in aquatic productivity occurred between 1700 and 1850 AD. The cores from the Eastern branch of Lago Bertrand are under investigation to confirm the extension of the sedimentological changes observed in the main lake. The main sedimentological change observed in Lago Bertrand occurs during an interval equivalent to a part of the Little Ice Age. A similar biogenic silica-rich layer was also recorded in another relatively distant lake (Lago Thompson at 45°30'S, 72°47

  8. PSV records from sediments of modern lakes (Aslikyl, Svir, Naroch).

    Kuzina, D.; Kosareva, L.; Nourgaliev, D.; Kosarev, V.


    During the last 20 years, our paleomagnetic group had investigated many lakes with the aim to know the behavior of the geomagnetic field during the Holocene. Lake sediments are the good presenters of the paleosecular variation (PSV) records. In this paper are presented materials from Lakes Aslikul (Russia, 54o 25' N, 54o 07' E), Svir (Belorussia, 54o 47' N; 26o 30' E), Naroch (Belorussia, 54o 51' N, 26o 51' E). Samples of lake floor sediments were collected using a piston corer designed and manufactured at the Kazan University as a prototype were used piston corer which had been designed and used by F. J. H. Mackereth. Three cores were collected from each Lake Aslikul and Svir and six cores from Lake Naroch. Cores length was between 3,5-6,5 meters. Sediments were subsampled into cubic nonmagnetic plastic boxes. Their magnetic susceptibilities were then measured using a MS2-B instrument, and their natural remanent magnetization (NRM) (module and direction) was measured using a JR-4 magnetometer. Based on this data were built generalized record for each parameter. We compared the geomagnetic field variations recorded in our study with the records reported in the literature for the sediments in the different lakes. Our data have a good PSV records correlation with other data so we can obtain age of sediments according to PSV records. The dating of lakes sediments was also improved and further detailed by radiocarbon dating that gave the same results. Some characteristic features, the B and S minima and the Y and E maxima (cf. nomenclature of Thompson and Turner, 1982) are recognized. All peaks have a wide but complicated structure. Studied lakes compared to the other European records available, it can be concluded that the PSV master curves obtained in this study can be used to model Holocene geomagnetic variations. The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University also by RFBR research projects No. 14

  9. Radium-226 in water, sediments, and fish from lakes near the city of Elliot Lake, Ontario, Canada.

    Clulow, F V; Davé, N K; Lim, T P; Avadhanula, R


    Ra-226 was measured by alpha-emission spectroscopy in water, sediments, and fish (tissues and gut contents), from five lakes in a watershed containing U mining and milling operations at Elliot Lake, Ontario, and from control lakes in an adjacent non-industrialized watershed. Ra-226 transfer parameters from lake water and sediments to fish tissues, and annual intakes by humans consuming fish, were estimated. Mean dissolved 226Ra levels ranged from approximately 76 mBq litre(-1) in water of the most affected lake, to Ra-226 levels in lake trout muscle were low and showed erratic variation among lakes whereas levels in whitefish muscle did not vary significantly among study and control sites. Lake herring (= cisco, Coregonus artedii), a planktivorous fish taken only from Quirke Lake, had mean 226Ra levels of 18 and 1.4 mBq g(-1) dry wt in bone and muscle, respectively. Gut 226Ra levels, highest in lake trout from McCabe and Quirke Lakes (126 +/- 53, 64 +/- 44 mBq g(-1) dry wt, respectively), and just detectable in McCabe and Elliot Lake whitefish (24 +/- 2, 36 +/- 14 mBq g(-1) dry wt, respectively), were below detection in lake trout and whitefish from other lakes. Concentration ratios (CRs) of 226Ra from water to muscle ranged from 8 to 14 in lake trout, 7 to 14 in whitefish, and 4 to 6 in lake herring. The water to bone CRs varied from 81 to 142, 314 to 548, and 126 to 272 in the same species. CRs were always 2 mSv year(-1)) and the public dose limit (5 mSv year(-1)).

  10. Bottom-sediment chemistry in Devil's Lake, northeast North Dakota

    Komor, S.C.


    Devils Lake is a 200 km2 terminal lake that contains sodium sulfate type water. Dissolved solids concentrations range from about 3,500 mg/L to 10,000 mg/L depending on location To investigate geochemical processes in the bottom sediments of Devils Lake, sediment cores were collected at two sites in the western half of the lake during a period of bottom water oxygen depletion. The upper 10 cm of the sediments consist of about 60 weight percent silicates (quartz, feldspar, and clays) 35 weight percent carbonates and 5 weight percent organic material. At depths between 1 and 3 cm in the sediments bacterial sulfate reduction and associated degradation of organic material cause minima in sulfate concentrations and δ13C values of dissolved inorganic carbon and maxima in alkalinity, ammonia, phosphate, and sulfide concentrations and δ34S values of dissolved sulfate. Downward increases of sodium, magnesium, potassium, and calcium concentrations result from upward diffusion of ions from saline pore water and dissolving sulfate minerals below 30 cm depth in the sediments.

  11. Sediment oxygen demand in upper Klamath and Agency lakes, Oregon, 1999

    Wood, T.M.


    Sediment oxygen demand (SOD) was measured in two shallow, interconnected lakes in southern Oregon, Upper Klamath Lake and Agency Lake, in spring and late summer of 1999. Upper Klamath Lake contains populations of two endangered fishes, the shortnose sucker and the Lost River sucker, and low dissolved oxygen concentrations in summer are thought to be one factor affecting sucker populations.

  12. Eutrophication History of Small Shallow Lakes in Estonia: Evidence from Multiproxy Analysis of Lake Sediments

    Koff, T.; Marzecova, A.; Vandel, E.; Mikomägi, A.; Avi, E.


    Human activities have impacted aquatic systems through the release of contaminants and the regulation of surface and groundwater. Although environmental monitoring has been essential in detecting eutrophication, biodiversity loss or water quality deterioration, monitoring activities are limited in time and are thus not sufficient in their scope to identify causality and thresholds. Paleolimnological studies increasingly show that the response of lakes to climatic and human influences is complex, multidimensional, and often indirectly mediated through watershed processes. In this study we examine the history of eutrophication processes in small lakes in Estonia using the multi-proxy analysis of sediment. Study sites represent lakes with different anthropogenic stressors: urbanisation and recreational use, run-off from an oil shale mine, and fish-kills and liming measures. We have used diverse analytical methods, such as elemental analysis, stable isotopes, fossil pigments, diatoms and Cladocera remains. The information derived from sedimentary indicators broadly agrees with the historical evidence of eutrophication and pollution. Moreover, the sediment records are indispensable for identifying additional issues such as: 1) earlier onset of cultural eutrophication; 2) the significant impact of catchment erosion on the deterioration of lake quality, particularly cyanobacterial blooms; and 3) changes in sedimentation processes with significance for internal biogeochemical cycling of nutrients. Importantly, the integration of several methods has significantly improved interpretation of sedimentary data and elucidated the different strengths of various indicator types. The project findings prove to be highly relevant for both the prediction of the ecological responses of lakes to different anthropogenic impacts and the establishment of reasonable reference target conditions in restoration schemes, as well as for methodological improvements of the sediment analysis.

  13. An Evaluation of Bera Lake (Malaysia Sediment Contamination Using Sediment Quality Guidelines

    Mohammadreza Gharibreza


    Full Text Available Bera Lake is known as the first RAMSAR site and is the largest natural lake in Malaysia. Sediment quality guidelines (SQGs and Geoaccumulation index were used to evaluate Bera Lake sediment contamination. Five undisturbed cores were collected from Bera Lake sediment. Major and trace levels of elements were determined for 132 subsamples using an inductively coupled plasma mass spectrometry (ICP-MS. The results marked two major groups of metallic elements bonded to the terrestrial and organic-rich sediments. Terrestrial sediments were strongly associated with accumulation of Li, Al, Pb, Cu, Cr, Na, Mg, Sr, and K during main fluxes of metals. However, a strong positive correlation was obtained between Fe, Mn, As, Zn, Cu, Ni, Ca, and Cd elements and TOC and TN. The Mn/Fe ratio revealed a long-term redox and acidic condition at Bera Lake. Geoaccumulation index for all individual metals has classified Bera Lake sediment as low to moderately polluted. However, elemental values when compared with thresholds limits of SQG indicated that Bera Lake sediments were contaminated by arsenic and iron. Results prove that deforestation during the five phases of land developments since 1972 has significantly contributed to the existence of metals fluxes into the area.

  14. The release of dissolved phosphorus from lake sediments.

    Boers, P.C.M.


    Chapter 1. Introduction: Eutrophication is one of the world's major water quality problems. Attempts to alleviate eutrophication of lakes have involved the control of phosphorus loadings. In such cases, an internal loading of phosphorus from the sediments may retard an improvement o

  15. Magnetic and geochemical signatures of flood layers in lake sediments

    Støren, Eivind; Paasche, Øyvind; Hirt, Ann; Kumari, Monika


    Floods carry sediments that quickly become deposited whenever rivers meet lakes. In catchments that are subjected to repeated flooding, downstream lakes can therefore contain record of past events across multiple timescales. High-resolution core scanning analyses such as X-ray fluorescence (XRF) scanning and magnetic susceptibility (MS) return data that are frequently used to detect flood layers in soft sediment archives such as lakes, fjords and ocean basins. In order to delineate the copious information that can be extracted from soft sediment records we have explored ways in which high-resolution data can be utilized and subsequently vetted by high-precision measurements. By combining magnetic hysteresis measurements and first-order reversal curves (FORCs) with inductively coupled plasma optical emission spectrometer (ICP-OES) measurements of chemical elements on 36 samples, important information not only about flood dynamics and variability are acquired, but also sources of noise in high-resolution scanning techniques are identified. Specifically, we show that a lake flood record from Southern Norway containing ˜ 100 floods distributed over 10 000 years can be sub-divided into at least two groups, suggested to contain floods generated by spring snow melting and intense summer rainstorms. The temporal evolution of this pattern shows a marked shift towards spring floods around 2000 years ago compared to the earlier part of the record. The approach presented here is of universal character and should be applicable to all kinds of soft sediment archives.

  16. Detecting Magnetosomes in Freshwater Lakes and Lake Sediments: A comparison of techniques

    Kodama, K. P.; Kim, B.; Kopp, R.; Chen, A. P.


    We will present a summary of the work done to date on detecting magnetosomes in the lake sediments and water column of Lake Ely, a small post-glacial lake in northeastern Pennsylvania. To establish that magnetosomes dominate the magnetic mineralogy of the Lake Ely sediments we sampled the water column every meter down to its maximum depth of 23 m and measured the dissolved oxygen, sulfide, and iron, as well as the ARM of the material filtered from the water. We examined the water samples for magnetotactic bacteria. These results established an increase in the ARM of the filtered material at the oxic-anoxic transition. They also showed that the ARM was carried by magnetosomes produced by magnetotactic bacteria living in the water column at depths from 15-19 m. TEM of magnetic separates collected from the lake sediments show that magnetosomes are transferred to the sediments from the water column and are a significant fraction of the magnetic minerals in the sediments. We used a variety of mineral magnetic techniques to magnetically characterize the magnetosomes in the lake sediments. The delta-delta ratio test of low temperature behavior at the Verwey transition (Moskowitz et al., 1993) gave values of 1.2 to 1.5, lower than the theoretically predicted level of 2 for magnetosomes, but a numeric unmixing technique could resolve higher delta-delta ratios in the dark organic-rich layers in the sediments where magnetosomes were more prevalent. ARM/SIRM ratios of 0.15 to 0.35 with Raf values (the crossover of an IRM acquisition curve versus its alternating field demagnetization curve) of 0.45 to 0.5 are consistent with the presence of magnetosomes in the sediments, the water column, and in a sediment trap located at the bottom of the lake. IRM and ARM acquisition modeling of samples collected from a 160 cm piston core revealed two components of magnetization with coercivities of about 25 mT and 65 mT that are identified as Egli's (2004) biogenic soft (BS) and biogenic

  17. Repeated sedimentation and exposure of glacial Lake Missoula sediments: A lake-level history at Garden Gulch, Montana, USA

    Smith, Larry N.


    Glaciolacustrine sediments record lake transgression, regression, and subaerial modification of the silty lake-bottom of glacial Lake Missoula in the Clark Fork River valley. The sequence preserved at Garden Gulch, MT documents lake-level fluctuations at >65% of its full-pool volume. Twelve sedimentary cycles fine upwards from (1) very fine-grained sandy silt to (2) silt with climbing ripples to (3) rhythmically laminated silt and some clay. The cycles are fine-grained turbidites capped locally by thin layers of angular gravel derived from local bedrock outcrops. The gravels appear to be the toes of mass wasting lobes carried onto the exposed lakebed surface during repeated lake-level lowerings. Periglacial wedges, small rotational faults, involutions, and clastic dikes deform the tops of eleven cycles. The wedges are 10-30 cm wide, penetrate 30-70 cm deep, are spaced seven cycles. The Garden Gulch section may represent as few as seven and as many as twelve substantial fillings and partial to complete drainings of glacial Lake Missoula.

  18. Assessment of Lake Orta sediments phytotoxicity after the liming treatment

    Daria ROSSI


    Full Text Available The paper presents results from seed germination and root elongation tests for the evaluation of Lake Orta sediment contamination. The protocol for this test was developed after a literature survey and careful investigation of the proper conditions for obtaining the germination of commercially available seeds of several plants. Cucumis sativus, Lactuca sativa, and Lepidium sativum were finally chosen and used to detect the phytotoxicity of both liquid and solid phases of Lake Orta sediments. To assess whether exchange at the water – sediment interface could represent a hazard for the environment and the actual bioavailability of the toxicants present into the sediments, the phytotoxicity of samples collected in 1992, 1994, 1996, 1997, and 1998 from selected stations was tested on seeds of three different plant species (Lactuca sativa, Lepidium sativum and Cucumis sativus. The obtained results allow drawing distribution maps of the germination index, which confirm the persistence of toxic effects. However, the lake seems to positively respond to the restoration treatment, since the more contaminated layers of sediments are presently buried under less toxic sediments.

  19. [Phylogenetic diversity of bacteria in soda lake stratified sediments].

    Tourova, T P; Grechnikova, M A; Kuznetsov, V V; Sorokin, D Yu


    Various previously developed techniques for DNA extraction from the samples with complex physicochemical structure (soils, silts, and sediments) and modifications of these techniques developed in the present work were tested. Their usability for DNA extraction from the sediments of the Kulunda Steppe hypersaline soda lakes was assessed, and the most efficient procedure for indirect (two-stage) DNA extraction was proposed. Almost complete separation of the cell fraction was shown, as well as the inefficiency of nested PCR for analysis of the clone libraries obtained from washed sediments by amplification of the 16S rRNA gene fragments. Analysis of the clone library obtained from the cell fractions of stratified sediments (upper, medium, and lower layers) revealed that in the sediments of Lake Gorchina-3 most eubacterial phylotypes belonged to the class Clostridia, phylum Firmicutes. They were probably specific for this habitatand formed a new, presently unknown high-rank taxon. The data obtained revealed no pronounced stratification of the spe- cies diversity of the eubacterial component of the microbial community inhabiting the sediments (0-20 cm) in the inshore zone of Lake Gorchina-3.

  20. Activities and geochronology of (137)Cs in lake sediments resulting from sediment resuspension.

    Matisoff, Gerald


    In lakes with a large surface area to watershed ratio (137)Cs delivery is primarily by direct atmospheric fallout to the lake surface, where its activity in the sediments has been used to estimate the exposure to organisms and sediment mass deposition rates. Comparison of (137)Cs in the historical atmospheric fallout record with (137)Cs activity profiles in sediment cores reveals that although the general features of a maxima in the fallout deposition can be matched to activity peaks in the core, the general shape of the (137)Cs profile is not an exact replica of the fallout history. Instead, the sediment reflects post-depositional processes such as resuspension, bioturbation, partitioning of (137)Cs between the sediment solids and the pore fluids, and molecular diffusion of (137)Cs through the pore fluids. Presented here is a model that couples these processes to a system time averaging (STA) model that accounts for the time history of (137)Cs fallout and the particle residence time in the water column or in the 'active' surface sediment subject to resuspension. Sediment profiles are examined by comparing reasonable ranges of each of the coefficients of each of these major processes and by applying the model to cores collected from two large, shallow lakes, Lake Erie (USA/Canada) and Lake Winnipeg (Canada). The results indicate that the STA model with molecular diffusion and sediment resuspension best describes the data from these large, shallow lakes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Environmental changes reflected by the lake sediments of the South Hongshan Lake, Northwest Tibet

    ZHU; Liping; (朱立平); CHEN; Ling; (陈; 玲); LI; Bingyuan; (李炳元); LI; Yuanfang; (李元芳); XIA; Weilan; (夏威岚); LI; Jianguo; (李建国)


    The 1.07-m long lake core with 1 cm interval cutting, which was obtained by drilling in the South Hongshan Lake of Northwest Tibet, was dated by the 210Pb and 137Cs methods, and a 150-year consecutive lake sedimentary sequence (1840─1997) with 1.4 year resolution was obtained. Some environmental proxies, such as the total organic carbon (TOC), total nitrogen (TN), ratio of TOC to TN (TOC/TN), trace chemistry elements (TCE), CaCO3, grain size, richness of ostracoda etc. showed that they are of well coincidence. These results implied that the environmental background varied from the cold-wet period in the late 19th century, to the warm-wet period from the end of the 19th century to the 1920s and to the warm-dry period since the 1920s. There were sub-variations since the 1920s: the cold-dry/warm-wet fluctuation from 1922 to 1960, the intensively warm-dry period since 1960 with a short cold-wet period in the mid-1970s to the end of the 1980s. The humid period from the mid-1970s to the end of the 1970s and the dry period beginning from the early 1980s were well documented by climatic data of the nearby weather station records while the grain size was well correlated to the annual precipitation. Compared with the records from Guliya ice core in the same area, the TOC proxy in the lake core indicating warm/cold conditions well corresponded to the ( 18O records representing temperature variations in the ice core. However, the proxies with dry/wet significance in the lake core were different from the variations of snow accumulation reflected by the ice core. It can be concluded that the chosen environmental proxies have clear environmental significance and the lake sediments can reflect climatic and environmental changes at high-resolution.

  2. Phosphorus forms and bioavailability of lake sediments in the middle and lower reaches of Yangtze River

    ZHU; Guangwei; QIN; Boqiang; ZHANG; Lu


    Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.

  3. Environmental changes on the Balkans recorded in the sediments from lakes Prespa and Ohrid

    B. Wagner


    Full Text Available Lakes Prespa and Ohrid on the Balkans are considered to be amongst the oldest lakes in Europe. Both lakes are hydraulically connected via karst aquifers. From Lake Ohrid, several up to ca. 15 m long sediment records were studied during the past years. In this study, a first long sediment record from Lake Prespa was studied in order to shed more light on the influence of Lake Prespa on Lake Ohrid and the environmental history of the region. Radiocarbon dating and the occurrence of 3 dated tephra layers provide a good age control and indicate that the 10.5 m long sediment record reaches back to 48 ka. The comparison of the results from this study with those from former studies of the Lake Ohrid cores indicates that Lake Prespa is more susceptible to environmental changes due to its lower volume and water depth. Glacial sedimentation is characterized by low organic matter contents and absence of carbonates in the sediments, which indicate oligotrophic conditions in both lakes. Holocene sedimentation is characterized by particularly high carbonate contents in Lake Ohrid and by particularly high organic matter contents in Lake Prespa, which indicate a shift towards more mesotrophic conditions in the latter. Long-term environmental changes and short-term events, such as the Heinrich events during the Pleistocene or the 8.2 cooling event during the Holocene, are well recorded in both lakes, but partly expressed in different proxies.

  4. Incorporation of Fine-Grained Sediment Erodibility Measurements into Sediment Transport Modeling, Capitol Lake, Washington

    Stevens, Andrew W.; Gelfenbaum, Guy; Elias, Edwin; Jones, Craig


    Capitol Lake was created in 1951 with the construction of a concrete dam and control gate that prevented salt-water intrusion into the newly formed lake and regulated flow of the Deschutes River into southern Puget Sound. Physical processes associated with the former tidally dominated estuary were altered, and the dam structure itself likely caused an increase in retention of sediment flowing into the lake from the Deschutes River. Several efforts to manage sediment accumulation in the lake, including dredging and the construction of sediment traps upriver, failed to stop the lake from filling with sediment. The Deschutes Estuary Feasibility Study (DEFS) was carried out to evaluate the possibility of removing the dam and restoring estuarine processes as an alternative ongoing lake management. An important component of DEFS was the creation of a hydrodynamic and sediment transport model of the restored Deschutes Estuary. Results from model simulations indicated that estuarine processes would be restored under each of four restoration alternatives, and that over time, the restored estuary would have morphological features similar to the predam estuary. The model also predicted that after dam-removal, a large portion of the sediment eroded from the lake bottom would be deposited near the Port of Olympia and a marina located in lower Budd Inlet seaward of the present dam. The volume of sediment transported downstream was a critical piece of information that managers needed to estimate the total cost of the proposed restoration project. However, the ability of the model to predict the magnitude of sediment transport in general and, in particular, the volume of sediment deposition in the port and marina was limited by a lack of information on the erodibility of fine-grained sediments in Capitol Lake. Cores at several sites throughout Capitol Lake were collected between October 31 and November 1, 2007. The erodibility of sediments in the cores was later determined in the

  5. Abrupt climate-triggered lake ecosystem changes recorded in late glacial lake sediments in northern Poland

    Slowinski, M. M.; Zawiska, I.; Ott, F.; Noryskiewicz, A. M.; Apolinarska, K.; Lutynska, M.; Michczynska, D. J.; Brauer, A.; Wulf, S.; Skubala, P.; Blaszkiewicz, M.


    The aim of this study was to better understand how local lake ecosystems responded to abrupt climate changes through applying multi-proxy sediment analyses. Therefore, we carried out a detailed and high-resolution case study on the late glacial sediment from the Trzechowskie palaeolake located in the eastern part of the Pomeranian Lakeland, northern Poland. We reconstructed climate induced environmental changes in the paleolake and its catchment using biotic proxies (macrofossils, pollen, cladocera, diatoms, oribatidae mite) and classical geochemical proxies (δ18O, δ13C, loss-on-ignition, CaCO3 content) in combination with high-resolution μ-XRF element core scanning. The core chronology has been established by means of biostratigraphy, AMS 14C-dating on plant macro remains, varve counting in laminated intervals and tephrochronology. The latter was possible by the discovery of the late Allerød Laacher See Tephra for the first time at such eastern location. Biogenic accumulation in the lake started rather late during the lateglacial interstadial at 13903×170 cal yrs BP. The rapid and pronounced cooling at the beginning of the Younger Dryas had a major impact on the lake and its catchment as clearly reflected by both, biotic and geochemical proxies. The depositional environment of the lake abruptly changed from a varved to massive gytjia. The pronounced warming at the demise of Younger Dryas cooling is well-reflected in all environmental indicators but with conspicuous leads and lags reflecting complex responses of lake ecosystems to climate warming. The research was supported by the National Science Centre Poland - NN306085037. This study is a contribution to the Virtual Institute ICLEA (Integrated Climate and Landscape Evolution Analysis) funded by the Helmholtz Association.

  6. Determining surface water and bed sediment quality of Lake Kopa

    Nurgul Kazangapovaa


    Full Text Available In this research, the results of a hydro-chemical study of Lake Kopa in Kazakhstan are described, in the context of the regional geography and aggravating ecological problems of the lake. Besides analyzing the concentrations of all major ions, heavy-metal ions and other pollutants, their vertical and horizontal distribution were also assessed. Moreover, water pollution indices (WPI were calculated for individual ions, classes of pollutants, and total pollution, revealing serious overload of human- induced pollution within the lake’s ecosystem. Concentrations of major ions and WPI were monitored over 2009-2013 period, revealing a distinct seasonal pattern and a multi-year periodicity in respect to the measured parameters. In addition, studying ion exchange between lake water and bottom sediment showed complex non-equilibrium processes besides leaching out Ca2+ and its exchange for Na+.

  7. Diversity and composition of bacterial community in soils and lake sediments from an Arctic lake area

    Nengfei Wang


    Full Text Available This study assessed the diversity and composition of bacterial communities within soils and lake sediments from an Arctic lake area (London Island, Svalbard. A total of 2,987 operational taxonomic units (OTUs were identified by high throughput sequencing, targeting bacterial 16S rRNA. The samples from four sites (three samples in each site were significantly different in geochemical properties and bacterial community composition. Proteobacteria and Acidobacteria were abundant phyla in the nine soil samples, whereas Proteobacteria and Bacteroidetes were abundant phyla in the three sediment samples. Furthermore, Actinobacteria, Chlorobi, Chlorofiexi, Elusimicrobia, Firmicutes, Gemmatimonadetes, Nitrospirae, Planctomycetes, Proteobacteria significantly varied in their abundance among the four sampling sites. Additionally, members of the dominant genera, such as Clostridium, Luteolibacter, Methylibium, Rhodococus, and Rhodoplanes, were significantly different in their abundance among the four sampling sites. Besides, distance-based redundancy analysis revealed that pH (p < 0.001, water content (p < 0.01, ammonium nitrogen (NH4--N, p < 0.01, silicate silicon (SiO42--Si, p < 0.01, nitrite nitrogen (NO2--N, p < 0.05, organic carbon (p < 0.05, and organic nitrogen (p < 0.05 were the most significant factors that correlated with the bacterial community composition. The results suggest soils and sediments from a lake area in the Arctic harbor a high diversity of bacterial communities, which are influenced by many geochemical factors of Arctic environments.


    Liancong LUO; Boqiang QIN; Guang GAO; Guangwei ZHU; Jinshan ZHANG


    Time-series measurements of wave, current and suspended sediment concentration (SSC) were made at three sites (Sites 1-3) and sediment samples were collected at different locations (Sites 4-7) in Lake Taihu. The significant wave height, length and period during the observation were 0.155m,3.45m and 1.9s and the mean current speed was 0.08m/s. The size distribution results show that the sediment is well sorted, coarse-skewed and very leptokurtic in the upper 10cm and clay and fine silt can account for more than 70% of the total within this depth. The median size remains constant vertically in the top 10cm in the eastern, southern, and northern areas of the lake, but changes significantly in the eastern area resulting from the short retention time of water in this area. The realistic settling velocity of suspended particles varies in the range of 0.01~0.05 cm s-1and they sink in a flocculated form rather than individually. Based on a simple mass flux model, the sediment erosion rate was estimated to range between 10-7 and 10-5kg/m2.s. The results in this study can be a great contribution to the development of a sediment transportation model in Lake Taihu.

  9. Sediment magnetic and paleomagnetic data from Buck Lake, Oregon

    Rosenbaum, J.G.; Reynolds, R.L.; Fitzmaurice, P.L.; Drexler, J.W.; Whitney, C.G.; Adam, D.P.


    Sediment magnetic and paleomagnetic studies were conducted on a core from Buck Lake, Klamath County, Oregon, that was collected as part of an investigation into the Quaternary climate history of the western United States. This report documents the methods used to obtain paleomagnetic directions, magnetic properties, and ancillary data, and presents these data in tabular form. Adam (1993) and Adam and others (1994) describe the site, the drilling methods, and lithology of the lacustrine sediments. Rosenbaum and others (1994) present preliminary interpretations of the sediment magnetic data and show that variations in magnetic properties closely reflect changes in climate as interpreted from the pollen record.

  10. Lake depth rather than fish planktivory determines cladoceran community structure in Faroese lakes - evidence from contemporary data and sediments

    Amsinck, S.L.; Strzelczak, A.; Bjerring, R.


    1. This study describes the environmental conditions and cladoceran community structure of 29 Faroese lakes with special focus on elucidating the impact of fish planktivory. In addition, long-term changes in biological structure of the Faroese Lake Heygsvatn are investigated. 2. Present-day species...... richness and community structure of cladocerans were identified from pelagial snapshot samples and from samples of surface sediment (0-1 cm). Multivariate statistical methods were applied to explore cladoceran species distribution relative to measured environmental variables. For Lake Heygsvatn, lake...... development was inferred by cladoceran-based paleolimnological investigations of a 14C-dated sediment core covering the last ca 5700 years. 3. The 29 study lakes were overall shallow, small-sized, oligotrophic and dominated by brown trout (Salmo trutta). Cladoceran species richness was overall higher...

  11. Lake-catchment systems and sediment information in Baikal district (Siberia and Mongolia)



    Sediment information is closely related to a lake-catchment system. Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka; the sediment discharge (sedimentation rate) in Baikal basically followed the global climatic change, whereas that in Khuvsgul did not always do so. An elementary mathematical model is used to explain the difference, considering changes in the catchment area and water level. Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area, which probably had a signiifcant inlfuence on Lake Khuvsgul and little inlfuence on Lake Baikal.

  12. A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

    Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden)


    This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial

  13. A preliminary magnetic study of Sawa lake sediments, Southern Iraq

    Ameen, Nawrass


    A preliminary magnetic study combined with chemical analyses was carried out in Sawa Lake in Al-Muthanna province, southern Iraq, about 22 km south west of Samawa city (31°18'48.80"N, 45°0'25.25"E). The lake is about 4.74 km length, 1.75 km width and 5.5 m height, it is surrounded by a salt rim which is higher than the lake water by about 2.8 m and sea water by about 18.5 m (Naqash et al., 1977 in Hassan, 2007). The lake is an elongated closed basin with no surface water available to it, it may be fed by groundwater of the Euphrates and Dammam aquifers through system of joints and cracks. This study aims to investigate the concentrations of selected heavy metals as pollutants and magnetic susceptibility (MS) and other magnetic properties of sediment samples from fifty sites collected from the bottom of the lake, the study area lies in an industrial area. The results show spatial variations of MS with mean value of about 4.58 x 10-8 m3 kg-1. Scanning electron microscopy and magnetic mineralogy parameters indicate the dominance of soft magnetic phase like magnetite and presence of hard magnetic phase like hematite. Spatial variations of MS combined with the concentrations of heavy metals suggests the efficiency of magnetic methods as effective, inexpensive and non-time consuming method to outlining the heavy metal pollution. References: Hassan W.F., 2007. The Physio-chemical characteristic of Sawa lake water in Samawa city-Iraq. Marine Mesopotamica, 22(2), 167-179.

  14. Particle induced X-ray emission of lake sediment

    Peaslee, G. F.; DeYoung, P. A. [Hope College, P. O. Box 9000 Holland, MI 49422 (United States)


    Three recent ion beam analysis research projects are described that have been undertaken by the Hope College Nuclear Group. Success in the routine ion beam analysis of lake sediment as well as the elemental analysis of lake sediment for environmental fingerprinting is reported. In addition, a novel ion beam analysis detection method for organo halogen flame retardants in polyurethane foam is proposed, and in each of these research projects significant student training has occurred. Building on the success of prior research published in both nuclear physics and applied physics, these projects involve undergraduate students in every aspect of the sample collection, data acquisition and data analysis. The combination of publishable scientific inquiry and undergraduate training using ion beam analysis is suggested as a model that could be done wherever there are appropriate accelerator facilities. (Author)

  15. Environmental records of carbon in recent lake sediments


    Based on careful sampling and accurate analysis of recent sediments in Lake Chenghai, this paper discusses the staggered positive/negative correlation between organic carbon (OC) concentration and inorganic carbon (IC) concentration. The result indicates that temperature change, and its induced relative changes are the main factors affecting the relationship between IC concentration, δ13C of carbonate and OC concentration. When temperature and its induced photosynthesis strength change control autochthonous calcite precipitation, OC concentration is positively correlated with IC concentration and δ13C of carbonate. When temperature and its induced physical/chemical changes dominate, OC concentration displays negative correlation with IC concentration and δ13C of carbonate. IC concentration and δ13C of carbonate in sediments of Lake Chenghai are good proxies for climatic warm/cold changes.

  16. Fractionation of Heavy Metals in Sediments from Dianchi Lake, China

    LI Ren-Ying; YANG Hao; ZHOU Zhi-Gao; L(U) Jun-Jie; SHAO Xiao-Hua; JIN Feng


    Fractionation of heavy metals in sediments can help in understanding potential hazards of heavy metals.The present study analyzed total concentrations and fractions of selected heavy metals(Cd,Cr,Cu,Pb,and Zn)in surfaca sediments from Dianchi Lake,Yunnan Province,China,as well as factors that may affect distributions of the various heavy metal fractions.Total concentrations of the heavy metals decreased in the order Zn>Cu>Pb>Cr>Cd.These heavy metals,except Cr,were much higher than their background levels,indicating that Dianchi Lake was polluted by Cd,Zn,Pb,and Cu.Cadmium occurred mainly as the non-residual fraction(sum of the HOAc-soluble,reducible,and oxidizable fractions)(97.6%),and Zn(55.7%)was also predominantly found in the non-residual fraction.In contrast,most of the Cr(88.5%),Pb(81.8%),and Cu(59.2%)occurred in the residual fraction.Correlation analysis showed that total heavy metal concentrations,organic matter and reducible Fe were the main factors affecting the distributions of the various heavy metal fractions.In the Waihai section of Dianchi Lake (comprising 97%of the lake area),the concentrations of Cd,Zn,Pb,and Cu in the non-residual fraction were significantly lower(P≤0.01 or 0.05)than those of the Caohai section (3% of the lake area).This indicated that potential heavy metal hazards in the Caohai section were greater than the Waihai section.

  17. Possible recording of the Mono Lake Excursion in cored sediment from Clear Lake, California

    Liddicoat, Joseph; Verosub, Kenneth


    We report the possible recording of the Mono Lake Excursion (MLE) in cored sediment from Clear Lake, CA. The locality (39.0˚N, 237.3˚E) is about 120 km north of San Francisco, CA, and 320 km northwest of the Mono Basin, CA, where the MLE first was discovered in North America (Denham and Cox, 1971). The field behaviour at Clear Lake that might be the MLE is recorded in clay and peaty clay about 50 cm below the top of the lowermost 80-cm core slug of a 21.6-m core. The coring was done by the wire-line method (Sims and Rymer, 1975) and the samples (rectangular solids 21 mm on a side and 15 mm high) were measured in a cryogenic magnetometer after demagnetization in an alternating field to 35 milliTesla (Verosub, 1977). The continuously-spaced samples record negative inclination of nearly 20˚ and northerly declination when unnormalized relative field intensity was reduced by an order of magnitude from the mean value. Those palaeomagnetic directions are followed immediately by positive inclination to about 50˚ and easterly declination of about 60˚ when the field intensity is at a relative high. That pattern of behaviour is recorded at three localities (Wilson Creek, Mill Creek, and Warm Springs) in the Mono Basin at the MLE (Liddicoat and Coe, 1979; Liddicoat, 1992). A path of the Virtual Geomagnetic Poles (VGPs) at Clear Lake form a clockwise-trending loop that is centered at 65˚N, 20˚E in the hemisphere away from the locality. The VGP that is farthest from the North Geographic Pole is at 29.3˚N, 337.1˚E, which is close to the path formed by the VGPs in the older portion of the MLE (Liddicoat and Coe, 1979; Liddicoat, 1992). The age of the sediment recording the anomalous palaeomagnetic directions in Clear Lake is about 30,000 years B.P. (Verosub, 1977). That age was determined from six (uncalibrated) radiocarbon dates, three of which are from near the base of the core (Sims and Rymer, 1975) where there are the anomalous palaeomagnetic directions, and linear

  18. Sedimentological characteristics of lake sediment of the Lake Jelonek (North Poland)

    Kramkowski, Mateusz; Filbrandt-Czaja, Anna; Ott, Florian; Słowiński, Michał; Tjallingii, Rik; Błaszkiewicz, Mirosław; Brauer, Achim


    Lake Jelonek is located in Northern Poland (53°45'58N, 18°23'30E). The lake is surrounded by forest, covers an area of 19,9 ha and has a maximum depth of 13,8 m. In 2013 and 2014 three overlapping and parallel series of long sediment cores JEL14-A-(1445 cm), JEL14-B-(1430 cm), JEL14-C-(1435 cm) and seven short gravity cores JEL13 (K1-K7) have been recovered from the deepest part of the lake. A continuous composite profile JEL14 covering 1426 cm has been established by correlation based on 28 distinct macroscopic marker layers. The sediment sequence can be divided into 15 (I-XV) lithological units. These units comprise biochemical calcite varves, homogeneous calcite-rich gyttja, homogeneous organic-diatomaceous gyttja, and sandy layers. The chronology established so far is based on 14 AMS 14C dates from terrestrial plant remains and tephrochronology (Askja AD-1875) and covers the interval from the Younger Dryas to present times. Based on the chronology and sedimentological characteristics the composite profile has been correlated to a previous core from which a detailed pollen diagram had been established (Filbrandt-Czaja 2009). Here we present initial results from thin section analyses for two intervals from the new composite record JEL14, (I) the uppermost 0-256 cm and (II) the interval from 768-1296 cm. Intercalated between these two varved interval is a thick section (512 cm) of homogeneous organic-ditomaceous sediments. We present varve micro-facies data in combination with μ-XRF element scanning for comprehensive reconstruction of the sedimentation processes in Lake Jelonek. Preliminary varve counting reveals that the uppermost 256 cm varved sediments comprise ca 925 years (2008-1083 AD), while the lower floating varve interval covers the time period from 1850 - 10500 cal a BP. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis -ICLEA- of the Helmholtz Association; grant number VH-VI-415. References

  19. Temporal and Spatial Dynamics of Sediment Anaerobic Ammonium Oxidation (Anammox) Bacteria in Freshwater Lakes.

    Yang, Yuyin; Dai, Yu; Li, Ningning; Li, Bingxin; Xie, Shuguang; Liu, Yong


    Anaerobic ammonium-oxidizing (anammox) process can play an important role in freshwater nitrogen cycle. However, the distribution of anammox bacteria in freshwater lake and the associated environmental factors remain essentially unclear. The present study investigated the temporal and spatial dynamics of sediment anammox bacterial populations in eutrotrophic Dianchi Lake and mesotrophic Erhai Lake on the Yunnan Plateau (southwestern China). The remarkable spatial change of anammox bacterial abundance was found in Dianchi Lake, while the relatively slight spatial shift occurred in Erhai Lake. Dianchi Lake had greater anammox bacterial abundance than Erhai Lake. In both Dianchi Lake and Erhai Lake, anammox bacteria were much more abundant in summer than in spring. Anammox bacterial community richness, diversity, and structure in these two freshwater lakes were subjected to temporal and spatial variations. Sediment anammox bacterial communities in Dianchi Lake and Erhai Lake were dominated by Candidatus Brocadia and a novel phylotype followed by Candidatus Kuenenia; however, these two lakes had distinct anammox bacterial community structure. In addition, trophic status determined sediment anammox bacterial community structure.

  20. Anthropogenic mercury signals in lake sediments from southernmost Patagonia, Chile

    Hermanns, Yvonne-Marie, E-mail:; Biester, Harald, E-mail:


    Atmospheric mercury fluxes to terrestrial and aquatic surfaces in the Northern Hemisphere have increased since the Industrial Revolution. However fluxes are not well characterized for the Southern Hemisphere, since environmental archives are comparatively scarce. Mercury records from {sup 210}Pb-dated sediment cores of three South Patagonian lakes were investigated in order to reveal the influence of anthropogenic activities on atmospheric mercury deposition in remote lakes of the Southern Hemisphere. Comparison with indicators of organic matter sources (carbon and nitrogen/carbon ratios) and a conservative mineral soil element (zirconium) in the sediments revealed that soil erosion is an important process contributing mercury to these lakes and influenced variation in concentrations through time. However, at ∼ 1900 AD mercury accumulation increased independent from soil erosion and peaked from 1980 to 2000 AD. We attribute this to an increase in atmospheric mercury deposition in this remote region of the Southern Hemisphere. Mean flux ratios, which reflect the increase in modern mercury accumulation compared to pre-1850 AD, lie within a range of 1.4 to 2.4. These values indicate an increase in atmospheric mercury deposition slightly lower than predictions derived from global mercury models that suggest an increase in Hg deposition by a factor of 2 to 3. - Highlights: ► Hg concentrations and accumulation rates were determined in South Patagonian lake sediments. ► Soil erosion was shown to account significantly for short-term variations in Hg accumulation. ► Increased Hg accumulation since 1900 AD (factor of 1.4–2.4) is attributed to a rise in atmospheric Hg. ► Accumulation of anthropogenic Hg peaked between 1980 and 2000 AD (∼ 3 μg m{sup −2} yr{sup −1})

  1. Heavy metals in bottom sediments of Lake Umbozero in Murmansk Region, Russia

    Jernström, Jussi; Lehto, J.; Dauvalter, A.;


    Sediment cores collected from different locations of Lake Umbozero were studied with respect to concentration and mobility of trace and heavy metals Co, Cu, Fe, Mn, Ni, Pb, U, and Zn. Lake Umbozero is the second largest lake in the Murmansk Region and subjected to contamination by air-borne emiss...

  2. Bioavailability and preservation of organic phosphorus in freshwater sediments and its role in lake eutrophication

    Lake eutrophication in China is a serious environmental concern, especially in lakes from the middle and lower reaches of Yangtze River region and Southwestern China Plateau. The dissolution of organic matter can result in release of phosphorus (P) from lake sediments and organic phosphate (Po) itse...

  3. Potential nitrate removal in a coastal freshwater sediment (Haringvliet Lake, The Netherlands) and response to salinization

    Laverman, A.M.; Canavan, R.W.; Slomp, C.P.; Van Cappellen, P.


    Nitrogen transformations and their response to salinization were studied in bottom sediment of a coastal freshwater lake (Haringvliet Lake, The Netherlands). The lake was formed as the result of a river impoundment along the south-western coast of the Netherlands, and is currently targeted for resto

  4. The mineral magnetic record of magnetofossils in recent lake sediments of Lake Ely, PA

    Kodama, K. P.; Moeller, R. E.; Bazylinski, D. A.; Kopp, R. E.; Chen, A. P.


    Mineral magnetic and ferromagnetic resonance (FMR) measurements made on the sediments from Lake Ely, Pennsylvania reveal the presence of magnetotactic bacteria magnetofossils. Saturation isothermal remanent magnetization (SIRM) data from a 1.25 m long piston core taken from the deepest part of the lake show a large intensity decrease at depths between 30 and 75 cm in the sediment column most likely the result of reductive diagenesis. Modeling of isothermal remanent magnetization (IRM) and anhysteretic remanent magnetization (ARM) acquisition data indicates the presence of biogenic soft (BS) and biogenic hard (BH) magnetosome coercivity components, even at depths in the core greatly affected by reductive diagenesis. First-order reversal curve distribution diagrams for two samples support this interpretation. Modeling of the FMR data also indicates the presence of the BS and BH magnetosome coercivity components, but the relative importance of the two components is opposite to that seen for the IRM and ARM acquisition modeling. A correlation between SIRM variations and local rainfall recorded over the past 70 years suggests that magnetofossil concentrations recorded paleo-rainfall variations in the most recent lake sediments. Multi-taper method spectral analysis of SIRM variations in the piston core, tied to time by varve counting from 1600 common era (CE) to 1128 before CE, show centennial scale periodicities similar to those observed in spectral analysis of a 230 year long historical rainfall record for the northeastern US reconstructed to Philadelphia, PA. This result indicates that enough magnetofossils can survive reductive diagenesis to retain a record of paleorainfall variations, suggesting that they can be a powerful paleoclimate proxy.

  5. Phosphorus, carbon and nitrogen enrichment during sedimentation in a seasonally anoxic lake (Lake Lugano, Switzerland

    Kurt W. Hanselmann


    Full Text Available Sedimentation fluxes of major nutrients are investigated during 1996 and 1997 at three different depths and two locations in eutrophic southern basin of Lake Lugano (Switzerland. Horizontal differences between the two sites are on the order of 10-40% (but can exceed 50%, whereas differences related to interannual oscillations range between 5 and 24%. Particulate organic carbon (POC and nitrogen (PN fluxes show a constant increase of 5-20% from the upper to the bottom trap. This tendency remains more or less constant during the year. On the contrary, particulate phosphorus (PP shows a seasonal variation, with higher accumulation rates from the I to the III trap in autumn and winter which can exceed +1200%. This phenomenon is due to the interaction between the dissolved phosphorus (DP and the iron(oxihydroxides (Fe(OH3 near the oxycline. Fe(OH3 precipitates at the iron redox boundary, scavenging DP. This enrichment flux increases together with the development of the anoxic benthic layer. The efficiency of the iron redox layer in trapping upward diffusing P is related to the concentration of dissolved iron in the anoxic hypolimnion. In Lake Lugano the two considered sites present major difference of iron concentration, and this difference is reflected in the P sedimentation fluxes. The exposition of an additional sedimentation trap above the maximal oxycline height has allowed to gain insight into this phenomenon.

  6. A Holocene Sediment Record From Lake Elsinore, Southern California: Evidence for Relative Lake Level Change and the Onset of ENSO.

    Kirby, M. E.; Lund, S. P.; Poulsen, C. J.


    There are very few complete terrestrial, Holocene paleoclimate records from coastal southwestern North America. Lake Elsinore, located 120km southeast of Los Angeles, represents one of the only natural, non-playa lakes in the region. Furthermore, it is well documented that coastal southwestern North America is highly sensitive to changes in atmospheric circulation and its affect on regional hydrodynamics. As shown by Kirby et al. (in press), modern lake levels at Lake Elsinore respond directly to total annual precipitation, particularly winter season amounts. The lake is also located along the eastern Pacific Ocean where changes in ocean circulation and its thermal structure modulate the overlying atmosphere, and thus the adjacent continental climate. Here, we present two 7 meter sediment core records from Lake Elsinore spanning the entire Holocene. Although the cores are from the lake's littoral zone, they show surprisingly complete records with very little lithologic evidence for major hiatuses. A combination of sedimentological analyses (e.g., mass magnetic susceptibility (CHI); total percent carbonate; total organic matter) and lithologic descriptions provide insight to lake dynamics over the Holocene. Using the historical calibration between magnetic susceptibility and relative lake level (i.e., high lake levels = high CHI values and vice versa) from Kirby et al. (in press), we developed a first-order estimate of Holocene relative lake levels for Lake Elsinore. The historic calibration is extrapolated through the sediment record based on the assumption that, like today, first order lake level change is directly related to precipitation amount. Both total percent carbonate and total organic matter support our historical calibration between CHI and lake level. Our data suggest a relative increase in lake levels during the mid-Holocene (ca. 8,000 cal yr BP) and through to the present day. From this observation, we hypothesize that regional hydrology as linked to

  7. Environmental Status and geochemical assessment Sediments of Lake Skadar, Montenegro.

    Kastratović, Vlatko; Jaćimović, Željko; Bigović, Miljan; Đurović, Dijana; Krivokapić, Slađana


    The environmental mobility and geochemical partitioning of ten metals were examined in sediments collected from the six locations around Lake Skadar in Montenegro. A three-step sequential extraction procedure was used to determine the distribution of the metals in various substrates of lacustrine sediments, and the concentrations were measured in the liquid extract by ICP-OES. The largest portion of the total amount of cadmium, strontium and manganese can be found in sediment bound to the hydrated iron and manganese oxides; cobalt, lead, copper and nickel in the oxidizable fraction and the highest portion of chromium, vanadium and zinc are in the residual fraction. The most mobilized and potentially mobile metals are strontium, cadmium and cobalt while the most immobilized metals are chromium, vanadium and zinc. Based on geochemical parameters, an assessment of sediment contamination by the investigated metals was performed and the results showed potential risks ranging from "no risk" to "low risk" to the environment.

  8. Distribution and factors affecting adsorption of sterols in the surface sediments of Bosten Lake and Manas Lake, Xinjiang.

    Liu, Jiang; Yao, Xiaorui; Lu, Jianjiang; Qiao, Xiuwen; Liu, Zilong; Li, Shanman


    This study investigated the concentrations and distribution of eight sterol compounds in the surface sediments of Bosten Lake and Manas Lake, Xinjiang, China. The ratios of sterols as diagnostic indices were used to identify pollution sources. The sediment of the two lakes was selected as an adsorbent to investigate the adsorption behaviour of sterols. Results showed that the sterols were widely distributed in the sediments of the lakes in the study areas. The total concentrations of the detected sterols in Bosten Lake and in Manas Lake were 1.584-27.897 and 2.048-18.373 μg g(-1)∙dw, respectively. In all of the sampling sites, the amount of faecal sterols was less than that of plant sterols. β-sitosterol was the dominant plant sterol with a mean concentration of 2.378 ± 2.234 μg g(-1)∙dw; cholesterol was the most abundant faecal sterol with a mean concentration of 1.060 ± 1.402 μg g(-1)∙dw. The pollution level was higher in Bosten Lake than in Manas Lake. Majority of the ratios clearly demonstrated that the contamination by human faecal sources was occurring at stations which are adjacent to residential areas and water inlets. The adsorption behaviour of sterols to sediment suggested that the sterol adsorption coefficients were reduced as temperature increased. As salinity increased, the adsorption quantity also increased. As pH increased, the sediment adsorption of sterol slightly increased because the strong alkaline solution is not conducive to the adsorption of sterols. The ratios between sterols did not change largely with the change in external factors.

  9. Microplastic pollution in Vembanad Lake, Kerala, India: The first report of microplastics in lake and estuarine sediments in India.

    Sruthy, S; Ramasamy, E V


    We present the first study of microplastics in the sediments of Vembanad Lake, a Ramsar site in India. Microplastics are emerging pollutants of increasing environmental concern with a particle size of microplastics pollution on the environment and biota is not well known. Vast data exist in the literature on marine microplastics while reports on freshwater ecosystems are scarce. In this context, to examine the occurrence of microplastic particles (MPs) in the Vembanad Lake, samples were collected from ten sites and processed for microplastic extraction through density separation. Identification of the polymer components of MPs was done using micro Raman spectroscopy. MPs were recovered from all sediment samples, indicating their extensive distribution in the lake. The abundance of MPs recorded from the sediment samples is in the range of 96-496 particles m(-2) with a mean abundance of 252.80 ± 25.76 particles m(-2). Low density polyethylene has been identified as the dominant type of polymer component of the MPs. As clams and fishes are the major source of protein to the local population, the presence of MPs in the lake becomes critically important, posing a severe threat of contaminating the food web of this lake. This study, being the first report from India on MPs in lake sediments, provide impetus for further research on the distribution and impact of this emerging pollutant on the biota of many aquatic systems spread across India.

  10. Sedimentation influx and volcanic interactions in the Fuji Five Lakes: implications for paleoseismological records

    Lamair, Laura; Hubert-Ferrari, Aurélia; Yamamoto, Shinya; El Ouahabi, Meriam; Garrett, Ed; Shishikura, Masanobu; Schmidt, Sabine; Boes, Evelien; Obrochta, Stephen; Nakamura, Atsunori; Miyairi, Yosuke; Yokoyama, Yusuke; De Batist, Marc; Heyvaert, Vanessa M. A.


    The Fuji Fives Lakes are located at the foot of Mount Fuji volcano close to the triple junction, where the North American Plate, the Eurasian plate and the Philippine Sea Plate meet. These lakes are ideally situated to study Mount Fuji volcanism and the interaction between volcanism, changes in lake sedimentation rates and the ability of lakes to record paleoearthquakes. Here, we present newly acquired geological data of Lake Yamanaka and Lake Motosu, including seismic reflection profiles, gravity and piston cores. These two lakes and their respective watersheds were affected by several eruptions of Mount Fuji. Lake Yamanaka, a very shallow lake (max. depth 14 m), was heavily impacted by the scoria fall-out of the A.D. 1707 Hoei eruption of Mount Fuji. A detailed investigation of the effect of the Hoei eruption was conducted on short gravity cores, using high resolution XRD, C/N and 210Pb/137Cs analyses. The preliminary results suggest that the sedimentation rate of Lake Yamanaka drastically reduced after the Hoei eruption, followed by an increase until the present day. Similarly, lacustrine sedimentation in Lake Motosu (max. depth 122 m) was disturbed by Mount Fuji volcanism at a larger scale. The watershed of Lake Motosu was impacted by several lava flows and scoria cones. For example, the Omuro scoria cone reduced the catchment size of Lake Motosu and modified its physiography. The related scoria fall out covered an extensive part of the lake catchment and reduced terrigenous sedimentary influx to Lake Motosu. Within the deep basin of Lake Motosu, seismic reflection data shows two different periods that are distinguished by a major change in the dominant sedimentary processes. During the first period, sublacustrine landslides and turbidity currents were the dominant sedimentation processes. During the second one, the seismic stratigraphy evidences only deposition of numerous turbidites interrupting the hemipelagic sedimentation. Changes in sedimentary processes

  11. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Gaskell, S. J.; Eglinton, G.


    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  12. Sterols of a contemporary lacustrine sediment. [in English postglacial lake

    Gaskell, S. J.; Eglinton, G.


    Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

  13. Sediment resuspension under action of wind in Taihu Lake, China

    Sha-sha ZHENG; Pei-fang WANG; Chao WANG; Jun HOU


    A field study was undertaken to investigate the changes of the current speed, wave parameters and sediment resuspension under different wind speeds in the Taihu Lake. The Acoustic Doppler Current Profiler (ADCP) and MIDAS DWR Wave Recorder were used to collect the data of currents and waves, respectively. The characteristics of sediment resuspension were investigated by a layered sampling technology. The measurement results showed that the current speed increased in direct proportion with the wind speed. Vertical distributions of the current speed represented significant inflection points at 0.4 of the relative water depth. Both the upper and lower layers followed logarithmic distributions. The mean wind speed and wave parameters (wave height and wave energy density) showed exponential distributions, meanwhile similar distribution was found between the mean wind speed and current speed. With rising surface wind, a corresponding increase in the concentration and particle size of the Suspended Particulate Matter (SPM) was observed in the water column. Different kinds of particles could influence the SPM concentration in the water column. The critical wind speed of sediment resuspension and the corresponding sediment incipient shear stress was found to be 3.7 – 4.0 m s-1 and 0.011 N m-2,respectively. The results of this study can be used to help understand and predict the changes of flow structure and water quality induced by different wind disturbances in shallow lakes.

  14. Ephemerality of discrete methane vents in lake sediments

    Scandella, Benjamin P.; Pillsbury, Liam; Weber, Thomas; Ruppel, Carolyn; Hemond, Harold F.; Juanes, Ruben


    Methane is a potent greenhouse gas whose emission from sediments in inland waters and shallow oceans may both contribute to global warming and be exacerbated by it. The fraction of methane emitted by sediments that bypasses dissolution in the water column and reaches the atmosphere as bubbles depends on the mode and spatiotemporal characteristics of venting from the sediments. Earlier studies have concluded that hot spots—persistent, high-flux vents—dominate the regional ebullitive flux from submerged sediments. Here the spatial structure, persistence, and variability in the intensity of methane venting are analyzed using a high-resolution multibeam sonar record acquired at the bottom of a lake during multiple deployments over a 9 month period. We confirm that ebullition is strongly episodic, with distinct regimes of high flux and low flux largely controlled by changes in hydrostatic pressure. Our analysis shows that the spatial pattern of ebullition becomes homogeneous at the sonar's resolution over time scales of hours (for high-flux periods) or days (for low-flux periods), demonstrating that vents are ephemeral rather than persistent, and suggesting that long-term, lake-wide ebullition dynamics may be modeled without resolving the fine-scale spatial structure of venting.

  15. Catchment sediment flux: a lake sediment perspective on the onset of the Anthropocene?

    Chiverrell, Richard


    Definitions of the Anthropocene are varied but from a geomorphological perspective broadly can be described as the interval of recent Earth history during which 'humans have had an 'overwhelming' effect on the Earth system' (Brown et al., 2013). Identifying the switch to a human-dominated geomorphic process regime is actually a challenging process, with in the 'Old World' ramping up of human populations and impacts on earth surface processes since the Neolithic/Mesolithic transition and the onset of agriculture. In the terrestrial realm lakes offer a unique window on changes in human forcing of earth surface processes from a sedimentary flux perspective, because unlike alluvial and hill-slope systems sedimentation is broadly continuous and uninterrupted. Dearing and Jones (2003) showed for a global dataset of lakes a 5-10 fold increase in sediment delivery comparing pre- and post-anthropogenic disturbance. Here sediment records from several lakes in lowland agricultural landscapes are presented to examine the changes in the flux and composition of materials delivered from their catchments. By definition the lakes record the switch to a human dominated system, but not necessary in accelerated sediment accumulation rates with changes in sediment composition equally important. Data from Crose, Hatch and Peckforton Meres, in lowland northwest England are interrogated producing quantitative land-cover reconstructions from pollen spectra calculated using the REVEALS model (Sugita, 2007), geochemical evidence for changes sediment provenance and flux, and 14C and stable Pb pollutant based chronological models detecting changes in sediment accumulation rate. The lake sediment geochemistry points to several phases of heightened human impact within these small agricultural catchments. Following small-in-scale forest cover reductions and limited impacts in terms of sediment flux during the Neolithic, the Bronze to Iron Age saw the first substantial reductions in forest cover

  16. Chironomidae (Diptera in the Himalayan Lakes – A study of sub-fossil assemblages in the sediments of two high altitude lakes from Nepal

    Subodh Sharma


    Full Text Available Chironomid head capsules were identified from sediment cores taken from Lake Gokyo (4750 m and Lake Gosaikunda (4350 m in the east-central Himalaya, to determine taxonomic composition of chironomid assemblages over time.  The sedimentation rate of Lake Gosaikunda was estimated at 0.05 cm/yr and that of Gokyo was estimated at 0.07 cm/yr by 210Pb and 137Cs dating.  Micropsectra sp. was dominant in the sediments of both lakesLake Gokyo sediments also contained Pseudodiamesa sp., Eukiefferiella/Tvetenia sp., Orthocladius/Cricotopus sp. and Rheocricotopus sp.  The concentration of headcapsules was nearly an order of magnitude greater in the Lake Gosaikunda core, which contained mostly Micropsectra sp. and Pseudodiamesa sp.  These taxa are typical of cold oligotrophic lakes.  Differences in lake depth, dissolved minerals, plus epi- and hypolimnetic temperature and dissolved oxygen suggest that stratification and temperature-induced increases in primary production may affect chironomid assemblages in these pristine lakes.  Palaeolimnological studies of Himalayan lakes should include replicate cores within lake, to increase headcapsule sample sizes given potentially high rates of sedimentation from glacial runoff. Key words: high altitude lakes, Himalaya, Chironomidae, palaeolimnology, Nepal

  17. Geomicrobiological Features of Ferruginous Sediments from Lake Towuti, Indonesia

    Vuillemin, Aurèle; Friese, André; Alawi, Mashal; Henny, Cynthia; Nomosatryo, Sulung; Wagner, Dirk; Crowe, Sean A.; Kallmeyer, Jens


    Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site—a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae, Chloroflexi, and Thermoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanomicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant

  18. Unravelling Copenhagen's stride into the Anthropocene using lake sediments

    Schreiber, Norman; Andersen, Thorbjørn J.; Frei, Robert; Ilsøe, Peter; Louchouarn, Patrick; Andersen, Kenneth; Funder, Svend; Rasmussen, Peter; Andresen, Camilla S.; Odgaard, Bent; Kjær, Kurt H.


    Industrialization including the effects of expanding energy consumption and metallurgy production as well as population growth and demographic pressure increased heavy-metal pollution loads progressively since the Industrial Revolution. Especially the burning of fossil fuels mobilizes heavy metals like lead and zinc on a large scale. By wet and dry deposition, these loads end up in the aquatic environment where sediments serve as sinks for these contaminations. In this study, we examine the pollution history of Copenhagen, Denmark. A sediment core was retrieved for the lake in the Botanical Gardens in central Copenhagen using a rod-operated piston corer. The water body used to be part of the old town's defence-wall system and was turned into a lake by terrain levelling in the mid 17th century. After initial X-ray fluorescence core scanning, element concentrations were determined using emission spectroscopy. The onset of gyttja accumulation in the lake is assumed to start immediately after the construction of the fortification in approximately AD 1645. An age model representing the last approximately 135 years for the uppermost 60cm was established by lead-210 and cesium-137 dating. The older part was dated via recognition of markedly increased levels of levoglucosan which are interpreted to be linked with recorded fires in Copenhagen. Similarly, two distinct layers interstratify the sediment column and mark pronounced increases of minerogenic material inflow which can be linked to known historical events. Significant pollution load increases are evident from the 1700s along with urban growth and extended combustion of carbon carriers fuels such as wood and coals. However, a more pronounced increase in lead and zinc deposition only begins by the mid-19th century. Maxima for the latter two pollutants are reached in the late 1970s followed by a reduction of emissions in accordance with stricter environmental regulations. Here, especially the phasing-out of tetraethyl

  19. Sources of mercury in sediments, water, and fish of the lakes of Whatcom County, Washington

    Paulson, Anthony J.


    Concerns about mercury (Hg) contamination in Lake Whatcom, Washington, were raised in the late 1990s after a watershed protection survey reported elevated concentrations of Hg in smallmouth bass. The U.S. Geological Survey, the Whatcom County Health Department, and the Washington State Department of Ecology (Ecology) cooperated to develop a study to review existing data and collect new data that would lead to a better understanding of Hg deposition to Lake Whatcom and other lakes in Whatcom County, Washington. A simple atmospheric deposition model was developed that allowed comparisons of the deposition of Hg to the surfaces of each lake. Estimates of Hg deposition derived from the model indicated that the most significant deposition of Hg would have occurred to the lakes north of the City of Bellingham. These lakes were in the primary wind pattern of two municipal waste incinerators. Of all the lakes examined, basin 1 of Lake Whatcom would have been most affected by the Hg emissions from the chlor-alkali plant and the municipal sewage-sludge incinerator in the City of Bellingham. The length-adjusted concentrations of Hg in largemouth and smallmouth bass were not related to estimated deposition rates of Hg to the lakes from local atmospheric sources. Total Hg concentrations in the surface sediments of Lake Whatcom are affected by the sedimentation of fine-grained particles, whereas organic carbon regulates the concentration of methyl-Hg in the surface sediments of the lake. Hg concentrations in dated sediment core samples indicate that increases in Hg sedimentation were largest during the first half of the 20th century. Increases in Hg sedimentation were smaller after the chlor-alkali plant and the incinerators began operating between 1964 and 1984. Analysis of sediments recently deposited in basin 1 of Lake Whatcom, Lake Terrell, and Lake Samish indicates a decrease in Hg sedimentation. Concentrations of Hg in Seattle precipitation and in tributary waters were

  20. A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

    Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden)


    This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial

  1. Unusual Holocene and late Pleistocene carbonate sedimentation in Bear Lake, Utah and Idaho, USA

    Dean, W.; Rosenbaum, J.; Skipp, G.; Colman, S.; Forester, R.; Liu, A.; Simmons, K.; Bischoff, J.


    Bear Lake (Utah-Idaho, USA) has been producing large quantities of carbonate minerals of varying mineralogy for the past 17,000 years. The history of sedimentation in Bear Lake is documented through the study of isotopic ratios of oxygen, carbon, and strontium, percent organic carbon, percent CaCO3, X-ray diffraction mineralogy, HCl-leach inorganic geochemistry, and magnetic properties on samples from three piston cores. Historically, the Bear River, the main source of water for Great Salt Lake, did not enter Bear Lake until it was artificially diverted into the lake at the beginning of the 20th century. However, during the last glacial interval, the Bear River did enter Bear Lake depositing red, calcareous, silty clay. About 18,000 years ago, the Bear River became disconnected from Bear Lake. A combination of warmer water, increased evaporation, and increased organic productivity triggered the precipitation of calcium carbonate, first as calcite. As the salinity of the lake increased due to evaporation, aragonite began to precipitate about 11,000 years ago. Aragonite is the dominant mineral that accumulated in bottom sediments of the lake during the Holocene, comprising an average of about 70 wt.% of the sediments. Aragonite formation in a large, cold, oligotrophic, high latitude lake is highly unusual. Lacustrine aragonite usually is found in small, saline lakes in which the salinity varies considerably over time. However, Bear Lake contains endemic ostracodes and fish, which indicate that the chemistry of the lake has remained fairly constant for a long time. Stable isotope data from Holocene aragonite show that the salinity of Bear Lake increased throughout the Holocene, but never reached highly evolved values of ??18O in spite of an evaporation-dominated water balance. Bear Lake hydrology combined with evaporation created an unusual situation that produced large amounts of aragonite, but no evaporite minerals.

  2. Sediment budget including the role of floodplains: the case of Lake Tana Basin (Ethiopia)

    Lemma, Hanibal; Admasu, Teshager; Dessie, Mekete; Fentie, Derbew; Poesen, Jean; Lanckriet, Sil; Adgo, Enyew; Nyssen, Jan


    Based on the collection of a large new dataset, we quantify the sediment 1) mobilized on the hillslopes surrounding Lake Tana (Ethiopia), 2) stored on the floodplains, 3) transported into the lake, 4) deposited in the lake and 5) delivered out of the lake so as to establish a sediment budget. In 2012 and 2013, suspended sediment concentration (SSC) and discharge measurements were made at 13 monitoring stations, including two lake outlets. 4635 SSC samples were collected and sediment rating curves that account for land cover conditions and rainfall seasonality were established for the 11 river stations, and mean monthly SSC was calculated for the outlets. Effects of the floodplain on rivers' sediment yield (SY) were investigated using the measurements at the upper and lower stations of Gilgel Abay, Gumara, Megech and Rib Rivers. SY from ungauged rivers was assessed using a model that includes catchment area and rainfall, whereas bedload and direct sediment input from lake shores were estimated. As a result, the gross annual SY from both gauged and ungauged rivers, bedload and lake shores was ca. 3.14 million tons, dominantly from Gilgel Abay and Gumara Rivers. The 0.48 million tons sedimentation in floodplains indicate that the floodplains serve as sediment sink. Moreover, annually about 1.09 million tons of sediment leaves the lake through the two outlets. Annual deposition in Lake Tana was about 1.56 million tons with a trapping efficiency of 60%. Furthermore, SSC and SY are generally higher at the beginning of the rainy season because soil in cultivated fields is bare and loose due to frequent ploughing and seedbed preparation. Later on in the season, increased crop and vegetation cover lead to a decrease in sediment supplies. Based on the established sediment budget and its calculated components, one can conclude that the expected lifetime of Lake Tana (20,396 years) is longer than what was anticipated in earlier studies.

  3. Developing inorganic carbon-based radiocarbon chronologies for Holocene lake sediments in arid NW China

    Zhang, Jiawu; Ma, Xueyang; Qiang, Mingrui; Huang, Xiaozhong; Li, Shuang; Guo, Xiaoyan; Henderson, Andrew C. G.; Holmes, Jonathan A.; Chen, Fahu


    Inorganic carbonates are often used to establish radiocarbon (14C) chronologies for lake sediments when terrestrial plant remains (TPR) are rare or when bulk organic matter is insufficient for dating, a problem that is common for many lakes in arid regions. However, the reservoir effect (RE), as well as old carbon contributed from the lakes catchment make it difficult to establish reliable chronologies. Here we present a systematic study of inorganic 14C ages of two lake-sediment sequences, one from a small-enclosed saline lake - Lake Gahai in Qaidam Basin, and the other from a large freshwater lake - Lake Bosten in Xinjiang. Modern dissolved inorganic carbon (DIC) of the lakes, paleo-lake sediments exposed in the catchment, and mollusk shells in core sediments from Lake Gahai were dated to assess the RE and the contribution of pre-aged carbon to the old ages in the cores. We propose a statistical regression to assess more than one RE for the 14C carbonate ages within our sedimentary sequences. Old radiocarbon ages contributed by detrital carbonates were assessed by comparing the ages of mollusk shells with those of carbonates at the same sediment depths. We established the RE of the authigenic component and assessed detrital old carbon contributions to our two sites, and this was used to correct the 14C ages. Based on this approach, we developed age models for both cores, and tested them using 210Pb ages in both cores and TPR-based 14C-ages recovered from Lake Bosten. We further tested our age models by comparing carbonate-based oxygen isotope (δ18O) records from both lakes to an independently-dated regional speleothem δ18O record. Our results suggest if sedimentary sequences are densely dated and the RE and the contribution of old carbon from detrital carbonates can be ascertained, robust chronological frameworks based on carbonate-based 14C determinations can be established.

  4. Chemical data for bottom sediment, lake water, bottom-sediment pore water, and fish in Mountain Creek Lake, Dallas, Texas, 1994-96

    Jones, S.A.; Van Metre, P.C.; Moring, J.B.; Braun, C.L.; Wilson, J.T.; Mahler, B.J.


    Mountain Creek Lake is a reservoir adjacent to two U.S. Department of the Navy facilities, the Naval Weapons Industrial Reserve Plant and the Naval Air Station in Dallas, Texas. A Resource Conservation and Recovery Act Facility Investigation found ground-water plumes containing chlorinated solvents on both facilities. These findings led to a U.S. Geological Survey study of Mountain Creek Lake adjacent to both facilities between June 1994 and August 1996. Bottom sediments, lake water, bottom-sediment pore water, and fish were collected for chemical analysis.

  5. The magnetic susceptibility measurements of turbidity current sediments from Fuxian Lake of Yunnan Province and their correlations with earthquakes


    This paper has advanced a new method for determining historical earthquakes. Its object of study is lake sediments. The research method is environmental magnetism represented by susceptibility. The purpose is extracting historical earthquake informations from lake sediments to explore the correlation between the turbidity current sediments initiated by the earthquakes and historical earthquakes round Fuxian Lake.

  6. Biomarkers and Metabolic Patterns in the Sediments of Evolving Glacial Lakes as a Proxy for Planetary Lake Exploration.

    Parro, Víctor; Blanco, Yolanda; Puente-Sánchez, Fernando; Rivas, Luis A; Moreno-Paz, Mercedes; Echeverría, Alex; Chong-Díaz, Guillermo; Demergasso, Cecilia; Cabrol, Nathalie A


    Oligotrophic glacial lakes in the Andes Mountains serve as models to study the effects of climate change on natural biological systems. The persistent high UV regime and evolution of the lake biota due to deglaciation make Andean lake ecosystems potential analogues in the search for life on other planetary bodies. Our objective was to identify microbial biomarkers and metabolic patterns that represent time points in the evolutionary history of Andean glacial lakes, as these may be used in long-term studies as microscale indicators of climate change processes. We investigated a variety of microbial markers in shallow sediments from Laguna Negra and Lo Encañado lakes (Región Metropolitana, Chile). An on-site immunoassay-based Life Detector Chip (LDChip) revealed the presence of sulfate-reducing bacteria, methanogenic archaea, and exopolymeric substances from Gammaproteobacteria. Bacterial and archaeal 16S rRNA gene sequences obtained from field samples confirmed the results from the immunoassays and also revealed the presence of Alpha-, Beta-, Gamma-, and Deltaproteobacteria, as well as cyanobacteria and methanogenic archaea. The complementary immunoassay and phylogenetic results indicate a rich microbial diversity with active sulfate reduction and methanogenic activities along the shoreline and in shallow sediments. Sulfate inputs from the surrounding volcanic terrains during deglaciation may explain the observed microbial biomarker and metabolic patterns, which differ with depth and between the two lakes. A switch from aerobic and heterotrophic metabolisms to anaerobic ones such as sulfate reduction and methanogenesis in the shallow shores likely reflects the natural evolution of the lake sediments due to deglaciation. Hydrodynamic deposition of sediments creates compartmentalization (e.g., sediments with different structure and composition surrounded by oligotrophic water) that favors metabolic transitions. Similar phenomena would be expected to occur on other

  7. Distributions of total mercury and methylmercury in surface sediments and fishes in Lake Shihwa, Korea.

    Oh, Sehee; Kim, Moon-Kyung; Yi, Seung-Muk; Zoh, Kyung-Duk


    The concentrations of total mercury (THg) and methylmercury (MeHg) in the sediments of Lake Shihwa, an artificial salt lake in Korea located near two large industrial complexes, were determined to investigate the state of Hg contamination in the lake sediments and the effect of local Hg source. THg and MeHg concentrations in the sediments, monitored for 2 years, ranged from 0.02 to 0.28 microg g(-1) and rain events and water gate operation may be additional important factors regulating Hg level and distribution in lake sediments. The levels of THg in fish species in this lake ranged from 9.8 to 35 ng g(-1), suggesting that the bioavailability of sediment Hg in the lake may be low. Although the THg concentrations in Lake Shihwa sediment were lower than those in other foreign study sites, they were higher than in neighboring coastal regions, and are constantly increasing. This result indicates that the nearby industrial complexes may be the major source of Hg found in the sediments of Lake Shihwa. Copyright 2009 Elsevier B.V. All rights reserved.

  8. In situ toxicity testing of Lake Orta sediments

    Monica BELTRAMI


    Full Text Available The use of in situ assays, which was initially proposed by Nebeker et al. (1984, is presently recognised as an effective tool to study the effects of contaminated sediments (Burton 1992. The placement of caged organisms to study short-term effects of exposure to contaminated environments has been employed for a number of aquatic species, both fish and invertebrate. This paper describes the application of this techniques to study the toxicity of Lake Orta sediments using both resident (Daphnia obtusa, D. longispina and non-resident (D. magna, Echinogammarus stammeri invertebrate species. In each of the selected stations, a group of four chambers, each containing 10 individuals, were deployed by scuba divers at 10 m depth and collected after 48 h. For each chamber, the surviving animals were counted, transferred to the laboratory and kept in Lake Orta water until their death. The number of neonates produced by each female in the laboratory was recorded daily in order to determine if the short exposure period could affect the reproductive behaviour of the animals. The technique and results reported here indicate the utility of in situ testing and suggest that, under certain conditions, this method of testing may yield results which are more representative of actual environmental conditions by avoiding the sample manipulation required for traditional laboratory toxicity tests.

  9. Improved understanding of Diatom stratigraphy in a varved sediment through lake monitoring and sediment trap data

    Maier, Dominique Beatrice; Bigler, Christian


    Biological remains in lake sediments reflect past conditions in the lake itself and within its catchment. However, it is difficult to disentangle to which extent the environmental drivers are natural (e.g. population dynamics, climate) or human-induced (e.g. agriculture, forestry). Therefore, comprehensive lake monitoring is crucial to understand taphonomy and sediment formation, and enhances the value of the paleolimnological archive. In this study, we analyze survey data of a varved lake in northern Sweden (Nylandssjön, Nordingrå) with special focus on the diatom record. Different monitoring components are combined, i.e. (1) bi-weekly data of chemical parameters (chlorophyll a, nutrients) covering the period from 2012 to 2015, (2) physical parameters (temperature, oxygen, ice-cover) covering the period from 2000-2015, (3) high-resolution data from a sequential sediment trap covering the period from 2000-2015 and (4) annually resolved diatom data from the sediment varves. Early and intense spring mixing in 2012 translates into a short but vertically pervasive chlorophyll a band which is simultaneously recorded in the sequential trap with a high diatom peak (500 000 valves cm2 d-1). The years 2013 and 2014 show higher chlorophyll a concentrations in the water column, but diatoms do not form a peak flux (>100 000 diatoms cm2 d-1) at any time in the sediment trap, probably due to stratification patterns. The trap record from 2012 indicates a spring bloom dominating the sediment signal, but this is not repeated in 2013 and 2014. Future analyses will be directed towards linking the monitored in-lake processes to annually or even seasonally resolved environmental characteristics. The multiplicity of potential ecological and environmental drivers led us to reverse our analytical view by starting with the diatom stratigraphy in the varved sediment, continuing through the data from sediment trap and water column into the lake catchment to identify deviations (timing

  10. Ozonation of sediments from an urban lake: an exploratory investigation

    F. A Lage Filho


    Full Text Available An exploratory investigation was conducted on the effects of application of ozone on the removal of organic and inorganic contaminants and the reduction of settleable solids in urban lake sediments. Homogenized sediment samples were treated in a batch reactor with an external recirculation loop and ozone feed from a Venturi injector. The ozone generating system was fed with ambient air with small footprint and operational simplicity. Ozone mass application (g/h and contact time (min were varied over wide ranges during testing. The effects of the ozone mass applied per unit time and the contact time on contaminant removal efficiencies were analyzed and a trade - off between the costs of ozonation and of solids treatment and disposal was proposed. The minimum ozone mass application required for total contaminant removal apparently depended on the type of organic contaminant present. An apparent influence of inorganic contaminant speciation on the removal efficiency was found and discussed.

  11. Composition of Humic Acids of the Lake Baikal Sediments

    Vishnyakova, O.; Chimitdorzhieva, G.; Andreeva, D.


    Humic substances are the final stage of the biogeochemical transformation of organic matter in the biosphere. Its natural compounds are found not only in soil, peat, coal, and sediments of basins. Chemical composition and properties of humic substances are determined by the functioning of the ecosystem as a whole. Therefore the study of the unique Lake Baikal sediments can provide information about their genesis, as well as the processes of organic matter transformation. For this purpose, preparations of humic acids (HA) were isolated by alkaline extraction method. The composition of HA was investigated by the elemental analyzer CHNS/O PerkinElmer Series II. Various located sediments of the Lake Baikal were the objects of the study: 1 - Chivyrkuisky Bay, 2 - Kotovo Bay, 3 - Selenga river delta near Dubinino village, 4 - Selenga river delta near Murzino village. Data on the elemental composition of HA in terms of ash-free portion show that the carbon content (CC) is of 50-53% with a maximum value in a sample 3, and minimum - in a sample 2. Such values are characteristic also for the soils with low biochemical activity. The hydrogen content is of 4,2-5,3%, a maximum value is in a sample 1. Data recalculation to the atomic percentages identified following regularities. The CC of HA is of 35-39 at. %. Hydrogen content is of 37-43 at. %. According to the content of these elements investigated substances are clearly divided into two groups: HA of the sediments of the Lake Baikal and river Selenga delta. The magnitude of the atomic ratio H/C can be seen varying degrees of condensation of the molecules of humic acids. The high atomic ratio H/C in HA of the former group indicates the predominance of aliphatic structures in the molecules. Humic acids of the later group are characterized by a low value H/C (organic matter of terrigenous origin, the remains of higher plants are the most source of it. In the bays of the Lake Baikal the remains of aquatic animal organisms, other

  12. Climatic record of the Iberian peninsula from lake Moncortes' sediments

    Cao, Min; Huguet, Carme; Rull, Valenti; Valero, Blas; Rosell-Mele, Antoni


    Climatic record of the Iberian peninsula from lake Moncortes' sediments Min Cao1, Carme Huguet1, Valenti Rull2, Blas L. Valero-Garces3, Antoni Rosell-Melé1,4 1Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain; 2Institut de Botanic de Barcelona (CSIC), Passeig del Migdia s/n, 08038, Barcelona, Spain, 3 Instituto Pirenaico de Ecologıa (CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain, 4Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain. The continuing buildup of industrial greenhouse gases in the atmosphere and concomitant increase in global temperatures has made much of the world's society aware that decades to centuries of environmental change lie ahead, and that these will have profound economic, political and societal impacts. The Iberian Peninsula lies in the boundary between tropical and subtropical climates and seems to amplify the climatic signals form the northern hemisphere through both atmospheric and water circulation feedbacks, making it an ideal site to monitor Northern hemisphere climate changes. This extreme sensitivity to climatic changes also makes the Iberian Peninsula extremely vulnerable to future climate changes. This is why understanding sensitivity to climate change and the consequences it will have on both climate and the hydrological cycle is key to implement preventive measures. The aim of our study is to come up with a high resolution quantitative reconstruction of climate variability (temperature, production and precipitation) in the Iberian Peninsula from lake sediments. We also want to establish the relation between those changes and the ones observed in both ice cores from Greenland and paleotemperature records from marine sediments of the continental Iberian margin. For these reasons we sampled a core in Moncortes (42.3N, 0.99E), a lake of karstic origin with an average depth of 25m and an area of 0

  13. Experimental study on phosphorus release from sediments of shallow lake in wave flume

    SUN; Xiaojing; ZHU; Guangwei; LUO; Liancong


    Influence of wave on sediment resuspension and nutrients release from sediments, collected from Lake Taihu and Lake Chaohu, was studied in flume experiments. Under strong-wave conditions, concentrations of suspended solids (SS), total phosphorus (TP) and dissolved total phosphorus (DTP) in overlying water were increased significantly following the sediments re-suspension. During the experiments on sediments of Lake Taihu and Lake Chaohu, TP concentrations increased 6 times and 3 times, and DTP concentration increased 100% and 70% more than it in presuspension, respectively. Concentration of soluble reactive phosphorus (SRP) of experiment on sediment of Lake Taihu increased 25%. During the massive sediment suspension, the dissolved phosphorus in pore water and much of the phosphorus adsorbed by the sediment particles were released into overlying water. The phenomena in this wave flume experiment are quite similar to the situation observed in situ of Lake Taihu. The critical wave stresses of sediment re-suspension are nearly equal. The change of concentrations of SS, TP, and SRP was the same as that in situ situation.This study showed that concentrations of TP and SRP in lake water could be increased significantly by wave disturbance. Phosphorus release was significantly enhanced by wave disturbance at the beginning of massive sediment re-suspension, but decreased later.

  14. Bathymetric mapping, sediment quality, and water quality of Lake Delhi, Iowa, 2001-02

    Schnoebelen, Douglas J.; McVay, Jason C.; Barnes, Kymm K.; Becher, Kent D.


    Lake Delhi was formed in 1929 when the Interstate Power Company dammed the Maquoketa River near Delhi, Iowa, for generation of hydroelectric power. The resulting 450-acre lake became a popular area in eastern Iowa for boating, swimming, and fishing. Hydroelectric power generation ended in 1973, and lakeside residents purchased the dam to maintain the recreational opportunities of the lake. Increasing concerns about sediment deposition and water quality by lakeside residents led to a 2-year study that included a bathymetric survey, an assessment of sediment quality, and an assessment of water quality of Lake Delhi.

  15. Radiometric dating of sediment records in European mountain lakes

    Peter G. APPLEBY


    Full Text Available Sediment cores from seven European mountain lakes collected as part of a study of palaeolimnogical records of climate change (the MOLAR project were dated radiometrically by 210Pb. In spite of the remote locations, only one site recorded more or less uniform sediment accumulation throughout the past 150 years. At three further sites the 210Pb record indicated uniform sedimentation up until ca 1950 but significant increases since then. Stratigraphic dates based on records of fallout 137Cs and 241Am showed that 210Pb supply rates to these core sites had nonetheless remained relatively constant and that the sediments could be dated by the CRS model. At the remaining sites there were indications of episodic changes in both sedimentation rates and 210Pb supply rates. Since the changes were not in proportion, neither of the simple dating models (CRS or CIC was applicable. Using the 137Cs and 241Am stratigraphic dates as reference points it was however possible to construct a realistic chronology for these cores by applying the CRS model piecewise to each time-bounded section.

  16. Nitrogen turnover in drying sediments of an Amazon floodplain lake.

    Koschorreck, Matthias


    In the Amazon floodplain large areas are subject to annual cycles of drying and rewetting. The turnover of nitrogen in the periodically drying sediments is an important regulator of floodplain fertility. In the present study the transition of a lake sediment from flooded to dry conditions was studied with respect to microbial nitrogen turnover. Soil nitrogen pools, as well as the activity and abundance of denitrifying and nitrifying bacteria, were investigated during one dry season. During the first weeks after drying, most of the inorganic nitrogen vanished from the sediment. The process was inhibited by a nitrification inhibitor, showing that coupled nitrification-denitrification was responsible for the nitrogen loss. Assimilation by plants or microbes, as well as leaching, were not important mechanisms of nitrogen loss. During a period of only 10 days, 59% of the total denitrification and 94% of the total N2O emission during the dry period occurred. Cell numbers of denitrifiers were not correlated with activities. Denitrification was not correlated with other sediment variables but was regulated by the patchy distribution of reduced and oxidized zones in the uppermost centimeters of the sediment. This heterogeneity was probably introduced by the bioturbation of small insects, which was restricted to a rather short time period shortly after drying.

  17. Organic sedimentation in modern lacustrine systems: A case study from Lake Malawi, East Africa

    Ellis, Geoffrey S.; Barry J. Katz,; Christopher A. Scholz,; Peter K. Swart,


    This study examines the relationship between depositional environment and sedimentary organic geochemistry in Lake Malawi, East Africa, and evaluates the relative significance of the various processes that control sedimentary organic matter (OM) in lacustrine systems. Total organic carbon (TOC) concentrations in recent sediments from Lake Malawi range from 0.01 to 8.80 wt% and average 2.83 wt% for surface sediments and 2.35 wt% for shallow core sediments. Hydrogen index (HI) values as determined by Rock-Eval pyrolysis range from 0 to 756 mg HC g−1 TOC and average 205 mg HC g−1 TOC for surface sediments and 228 mg HC g−1 TOC for shallow core samples. On average, variations in primary productivity throughout the lake may account for ~33% of the TOC content in Lake Malawi sediments (as much as 1 wt% TOC), and have little or no impact on sedimentary HI values. Similarly, ~33% to 66% of the variation in TOC content in Lake Malawi sediments appears to be controlled by anoxic preservation of OM (~1–2 wt% TOC), although some component of the water depth–TOC relationship may be due to physical sediment transport processes. Furthermore, anoxic preservation has a minimal effect on HI values in Lake Malawi sediments. Dilution of OM by inorganic sediment may account for ~16% of variability in TOC content in Lake Malawi sediments (~0.5 wt% TOC). The effect of inputs of terrestrial sediment on the organic character of surface sediments in these lakes is highly variable, and appears to be more closely related to the local depositional environment than the regional flux of terrestrial OM. Total nitrogen and TOC content in surface sediments collected throughout the lake are found to be highly correlated (r2 = 0.95), indicating a well-homogenized source of OM to the lake bottom. The recurring suspension and deposition of terrestrial sediment may account for significant amounts of OM deposited in offshore regions of the lake. This process effectively separates denser

  18. Paleosandstorm characteristics and lake evolution history deduced from investigation on lacustrine sediments--The case of Hongjiannao Lake, Shaanxi Province

    SHEN Ji; WANG Yong; YANG Xiangdong; ZHANG Enlou; YANG Bao; JI Junfeng


    Sediment cores from desert lakes serve as good records of the frequency and intensity of sandstorms in history. By multi-proxy analysis of grain-size, magnetic susceptibility, TOC and Rb/Sr ratio, the paleosandstorm characteristics and lake evolution history in Yulin Area for the past 80 years. are discussed in this article. It is revealed that Hongjiannao Lake formed in about 1928 A.D. and in its initial stage sandstorms were prevalent with three extremes taking place in 1936 A.D., 1939 A.D. and 1941 A.D.. During the expansion period of 1952―1960 A.D., inflow waters to the lake increased sharply and a lot more weathered materials were carried into the lake. The frequency and intensity of sandstorms have reduced a lot since 1960s and the "double peaks" feature of the grain-size frequency curve has changed into the "single peak" feature. Study on the catchment ecology of the lake shows that the occurrence of sandstorms has been effectively restrained by the forest plantation and water and soil conservation.

  19. Spatial Variation of P and N in Water and Sediments of Dianchi Lake, China

    L(U) Jun-Jie; YANG Hao; GAO Li; YU Tian-Ying


    Dianchi Lake is one of the most eutrophic lakes in China. In order to understand this eutrophication and to help control the pollution, this research investigated the spatial distribution of Kjeldahl nitrogen (K-N) and total phosphorus(TP) through analysis of bottom water and sediment (3 depths) samples collected at 118 sites around Dianchi Lake. The concentrations of K-N and TP for the lake bottom water in the Caohai part of the lake were much higher than those in the Waihai part, generally decreasing from north to south. In the sediments, the K-N concentration was higher in the Caohai part and the middle of the Waihai part. On the other hand, TP in the sediments was greater in the southern and western parts. Both K-N and TP had similar spatial distributions for the sediment samples of three different depths.Vertically, the K-N and TP concentration in the sediments decreased with an increase in depth. This was evidence that eutrophication and pollution of Dianchi Lake was becoming gradually more severe. Exterior factors including uncontrolled input of domestic and industrial effluents as well as non-point pollution around the lake were the main reasons for serious eutrophication; therefore, controlling these was the first step in reducing eutrophication of Dianchi Lake.

  20. Chemical forms and extractability of iron in sediments of three contrasting lakes of China and UK

    ZHOU Qi-xing; Gibson C.E.; Stewart B.M.


    Iron is a limiting factor for the eutrophication of lakes, especially those lakes that are enriched with phosphorus. Extractability of iron in sediments of West Lake and Taihu Lake in China and Lower Lough Erne in Northern Ireland of UK was comparatively investigated on the basis of analysing chemical forms of iron using different extractants. It was shown that extractable iron in sediments of the lakes was greatly different using various extractants. Reactive iron or easily released iron such as "active" iron oxides, total free iron oxide and water-soluble iron was not high, only accounting for 0.01%-0.15% of total iron. The efficiency of the extractants for exchangeable iron was decreased in the sequence 0.1 mol/L HCl> DTPA + TEA mixed solution > 1 mol/L NH4OAc > 0.5 mol/L MgCl2 = 0.5 mol/L CaCl2. It seems that the complexion of iron by organic matter was not strong because the concentration of organically bound iron was significantly lower than the concentration it was forecasted. Extractable iron is not entirely consistent with or dependent on total iron in lake sediments. To a certain extent,phosphate can inhibit the release of iron in sediments of the lakes. The selection of extractants is thus the first key step to evaluate bioavailability of iron in lake sediments.

  1. First investigation of desert Lake Hongjiannao,Shannxi Province based on its sediment study

    WANG Yong; SHEN Ji; YANG Xiangdong; ZHANG Enlou; LIU Xingqi; LIU Enfeng; XIAO Xiayun


    By multi-proxy analysis of grain-size, magnetic susceptibility (MS), Fe/Mn and Rb/Sr ratios, TOC and other chemical elements, environmental changes in the Hongjiannao Lake over the past 80years were discussed. It is revealed that the lake formed during 1928 - 1952 A. D. , characterized by relatively high Fe/Mn ratio and lower Rb/Sr ratio, MS value and lake productivity. During this period sandstorms were prevalent with three extremes occurring in 1936, 1939 and 1941 A. D. , respectively. In the short time period of 1952 - 1960 A. D. , the water level of the lake rose remarkably, as shown by a sharp increase in coarse slit and MS value, as well as the obvious dilution of geochemical element concentrations in lake sediments. The lake expansion is ascribed to both much more rainfall and human activities, especially in about 1958 A. D. , when a great deal of channeled-off water from the around swamps was let to inpour into the lake. The lithological characteristics and sediment proxies reflect that the Hongjiannao Lake has already developed into a stable deep lake since the 1960s, characterized by the higher lake productivity and Rb/Sr ratio and lower Fe/Mn ratio. The frequency and intensity of sandstorms have also reduced greatly since the 1960s due to natural conservation activities. The drop of water level since the middle of the 1990s may be related to a warm and dry climate.

  2. A New 62-sample Record of the Mono Lake Excursion Waveform from the Depocenter Sediments of Summer Lake, OR

    Negrini, R. M.; McCuan, D. T.; Horton, R. A.; Verosub, K. L.


    A new core from Summer Lake, Oregon provides the primary datset for a composite, 62-sample record of the Mono Lake Excursion (MLE) waveform. The magnetograms and virtual geomagnetic poles (VGPs) are consistent with those associated with the MLE record from Mono Lake (e.g., Liddicoat and Coe, 1979). The added detail from this new record firmly establishes three distinct VGP clusters centered first on easternmost Asia/Siberia, then on Europe, and, finally, on North America. The jumps between clusters involve typically one sample, which represents only a few decades of time. The excursion is bracketed by tephra of known age (the Mount St. Helens Cy 46.0 ± 6 ka and the Wono 27.3 ± 0.3 14C kyr B.P.) and the age of the excursion is ~28 14C kyr B.P based on an average of five radiocarbon ages from below, within and above the excursion interval. A second waveform that exhibits shallowing inclinations and easterly declination swings upsection is truncated by a prominent unconformity. These PSV features and the associated RPI leading up to this unconformity correlate with those of the onset of the Laschamp Excursion (Lund et al., 2005). Both radiocarbon and PSV correlations support missing sediment from the Summer Lake record between 42.5 and 38 GISP2 ka. This sediment hiatus correlates to unconformities or lowstands in other Great Basin lakes suggesting a Heinrich 4-induced drought that affected much of western North America.

  3. Arctic deltaic lake sediments as recorders of fluvial organic matter deposition

    Vonk, Jorien; Dickens, Angela; Giosan, Liviu; Zipper, Samuel; Galy, Valier; Holmes, Robert; Montlucon, Daniel; Kim, Bokyung; Hussain, Zainab; Eglinton, Timothy


    Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13C, 14C) and molecular organic geochemistry (lignin, leaf waxes). High-resolution age models (137Cs, 210Pb) of downcore lake sediment records (n=11) along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels). Comparison with earlier published Mackenzie River depth profiles shows that (i) lake sediments reflect the riverine surface suspended load, and (ii) hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale) riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.

  4. Arctic deltaic lake sediments as recorders of fluvial organic matter deposition

    Jorien E Vonk


    Full Text Available Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13C, 14C and molecular organic geochemistry (lignin, leaf waxes. High-resolution age models (137Cs, 210Pb of downcore lake sediment records (n=11 along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels. Comparison with earlier published Mackenzie River depth profiles shows that (i lake sediments reflect the riverine surface suspended load, and (ii hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.

  5. Human Influence on Heavy Metal Distribution in the Upper Lake Nansi Sediments, Shandong Province, China

    杨丽原; 沈吉; 张祖陆; 金章东; 朱育新


    Core and surface sediment samples were collected from three sub-lakes (Lake Nanyang, Lake Dushan and Lake Zhaoyang) in the Lake Nansi Basin, Shandong Province. In order to reveal the characteristics of spatial and historical distribution of heavy metals in different sub-lakes of the Upper Lake Nansi, heavy metal (As, Cr, Cu, Hg, K, Mn, Ni, Pb, Zn, Al, Fe, Ti and V) concentrations of sediment samples were investigated. Based on the activity of 137 Cs in the sediments, the modern accumulation rate of Lake Nansi sediments is 3.5 mm/a. Our results show that the whole Upper Lake Nansi has been already polluted by heavy metals, among which Lake Nanyang has been polluted seriously by mercury, as well as by lead and arsenic, while Lake Dushan has been most seriously polluted by lead and arsenic. Historical variation of heavy metal (Cr, Cu, K, Ni, Zn, Al, Fe, Ti and V) concentrations shows an abrupt shift in 1962, resulting in a division of two periods: from 1957 to 1962 when metal enrichment increased with time, and from 1962 to 2000 when it decreased with time, while that of some anthropogenic elements such as Hg, Pb and Mn tend to increase toward the surface. However, the variation trend of As in the sediments is different from that of Hg, Pb and Mn, with its maximum value appearing in 1982. Since 1982 the concentrations of As have decreased due to the forbidden use of arsenite pesticides. This variation trend revealed changes in manner of human activity (coal combustion, waste discharges from both industries and urban sewage) within the catchment during different periods.

  6. The use of Pb-210 to normalize fluxes and burdens of atmospheric contaminants in lake sediment cores

    Brunskill, G.J.; Wilkinson, P.; Hunt, R.; Muir, D.; Billeck, B.; Lockhart, L. (Freshwater Inst., Winnipeg, Manitoba (Canada))


    It is possible to estimate the local annual atmospheric flux (Bq/m[sup 2] [sm bullet] yr) of Pb-210 to land and lake surfaces from measurements of the integral of excess Pb-210 in soil and peat profiles. If you compare this average Pb-210 flux to the soil surface, to the Pb-210 flux to deep lake sediments, you will usually find that the lake sediment flux is a factor of 2 to 6 greater. This is because most of the clay-sized and organic material added to the lake (and resuspended in the lake) each year is funneled into the deeper parts of the lake basin. The ratio of the deep lake Pb-210 sediment flux to the average terrestrial soil Pb-210 flux will be called the focusing factor, which can be used to crudely estimate whole lake sedimentation rates (g/m[sup 2] lake surface area [sm bullet] yr). Many industrial and agricultural contaminants are delivered to remote lakes by atmospheric deposition, and those contaminants that are strongly particle reactive will usually be resuspended and funneled into the deeper parts of the lake basin similar to Pb-210. Often a single sediment core history of deposition is used to estimate contaminant burdens and fluxes at the coring site in a lake basin. These deep basin contaminant burdens and fluxes can be divided by the focusing factor to estimate the burden per unit lake surface area and the atmospheric deposition rate to the lake surface area.

  7. Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

    V. Wennrich


    Full Text Available Lake El'gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most long-lasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical, and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a wind-induced two-cell current system as major driver of sediment transport and accumulation processes in Lake El'gygytgyn. The distribution of mafic rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitation of these elements with Fe and Mn hydroxides and oxides. But the similar distribution of organic matter and clay contents might also point to a fixation to organic components and clay minerals. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the modern lake processes of Lake El'gygytgyn and its lake-catchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive.

  8. Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

    V. Wennrich


    Full Text Available High Arctic Lake El'gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most long-lasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a wind-induced two-cell current system as major driver of sediment transport and accumulation processes in Lake El'gygytgyn. The distribution of mafic-rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitaion of these elements with Fe and Mn hydroxides and oxides. But the akin distribution of organic matter content might also point to a fixation to organic components. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the in-lake processes of Lake El'gygytgyn and its lake-catchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive.

  9. Sediment sequences and palynology of outer South Bay, Manitoulin Island, Ontario: Connections to Lake Huron paleohydrologic phases and upstream Lake Agassiz events

    Lewis, C. F. M.; Anderson, T. W.


    South Bay on the southern coast of Manitoulin Island is a fjord-like embayment connected to Lake Huron by a natural narrow gap in the bay's outer sill 6.5-14 m above the lake. A seismic profile, pollen, plant macrofossil, grain size analyses, and other sediment properties of two piston cores from a shallow outer basin of the bay document a 9 m-thick sediment section comprising rhythmically laminated clay under silty clay containing zones with small molluscan shells and marsh detritus. A sandy pebbly layer under soft silty clay mud overlies these sediments. This stratigraphy represents inundation by deep glacial Lake Algonquin followed by the shallowing Post Algonquin series of lakes, and exposure in the early Holocene by 5 Lake Stanley lowstands in the Lake Huron basin separated by 4 Lake Mattawa highstands. Overflow from South Bay in the first lowstand is thought to have eroded the outer sill gap. Marsh environments are inferred to have formed in the bay during subsequent lowstands. The Lake Mattawa highstands are attributed to outburst floods mainly from glacial Lake Agassiz. Palynological evidence of increased spruce occurrence, an apparent regional climate reversal, during the dry pine period is attributed to cold northwest winds from the Lake Superior basin and a lake effect from the Mattawa highstands in the Lake Huron basin. Lake waters transgressed South Bay following the pine period to form the Nipissing shore on Manitoulin Island. Transfer of Lake Huron basin drainage to southern outlets and continued glacioisostatic uplift of the region led to the present configuration of South Bay and Lake Huron.

  10. Identification of contamination in a lake sediment core using Hg and Pb isotopic compositions, Lake Ballinger, Washington, USA

    Gray, John E.; Pribil, Michael J.; Van Metre, Peter C.; Borrok, David M.; Thapalia, Anita


    Concentrations and isotopic compositions of Hg and Pb were measured in a sediment core collected from Lake Ballinger, near Seattle, Washington, USA. Lake Ballinger has been affected by input of metal contaminants emitted from the Tacoma smelter, which operated from 1887 to 1986 and was located about 53 km south of the lake. Concentrations and loadings of Hg and Pb in Lake Ballinger increased by as much as three orders of magnitude during the period of smelting as compared to the pre-smelting period. Concentrations and loadings of Hg and Pb then decreased by about 55% and 75%, respectively, after smelting ended. Isotopic compositions of Hg changed considerably during the period of smelting (δ202Hg = −2.29‰ to −0.38‰, mean −1.23‰, n = 9) compared to the pre-smelting period (δ202Hg = −2.91‰ to −2.50‰, mean −2.75‰, n = 4). Variations were also observed in 206Pb/207Pb and 208Pb/207Pb isotopic compositions during these periods. Data for Δ199Hg and Δ201Hg indicate mass independent fractionation (MIF) of Hg isotopes in Lake Ballinger sediment during the smelting and post-smelting period and suggest MIF in the ore smelted, during the smelting process, or chemical modification at some point in the past. Negative values for Δ199Hg and Δ201Hg for the pre-smelting period are similar to those previously reported for soil, peat, and lichen, likely suggesting some component of atmospheric Hg. Variations in the concentrations and isotopic compositions of Hg and Pb were useful in tracing contaminant sources and the understanding of the depositional history of sedimentation in Lake Ballinger.

  11. Sediment transport and deposition in Lakes Marion and Moultrie, South Carolina, 1942-85

    Patterson, G.G.; Cooney, T.W.; Harvey, R.M.


    Lakes Marion and Moultrie, two large reservoirs in the South Carolina Coastal Plain, receive large inflows of sediment from the Santee River. The average rate of sediment deposition for both lakes during the period 1942-85 was about 0.06 inch per year, or about 800 acre-feet per year. The rate during 1983-85 was about 0.037 inch per year, or about 490 acre-feet per year, reflecting the decreasing trend in sediment inflow. This is a reversal of a trend toward increasing suspended- sediment concentrations in streams that were caused by farming practices in the southern Piedmont from about 1800 to about 1920. Only a small part of the eroded sediment has been carried out of the Piedmont, but the remaining sediment is becoming less available for transport. Sediment deposition is concentrated in several areas of upper Lake Marion where the velocity of the incoming water decreases significantly. Beds of aquatic macrophytes appear to encourage deposition which, in turn, creates favorable habitat for the plants. The rate of sediment accumulation in Lakes Marion and Moultrie averaged 650,000 tons per year during 1983-85, reflecting a trap efficiency of 79 percent of the total sediment inflow of 825,000 tons per year. Thickness of post-impoundment sediment varies from about 11 feet near the mouth of the Santee River in Lake Marion to 0 feet in Lake Moultrie near Bonneau. Sediments in Lake Marion tend to have finer texture and higher contents of organic matter, nutrients, and trace metals than those in Lake Moultrie.

  12. Improved prediction of vegetation composition in NW European softwater lakes by combining location, water and sediment chemistry

    Pulido Pérez, Cristina; Jensen, Kaj Sand; Lucassen, Esther C.H.E.T.;


    composition. This complex analysis can also account for high sediment variability in the littoral zone of individual lakes, by using site-specific physico-chemical sediment factors, and offer better predictions of vegetation composition when lake water chemistry is relatively homogeneous among lakes within...

  13. Content and Ecological Risk Assessment of Heavy Metals in Surface Sediment in Weishan Lake


    [Objective] The aim was to analyze the content of heavy metals in surface sediment in Weishan Lake and further assess its ecological risk.[Method] Heavy metal pollution in surface sediment in Weishan Lake was studied,and the pollution indices and potential ecological risk indices of Cu,Zn,Pb,Cd and Cr were calculated to assess the potential ecological risk of heavy metal pollution.[Result] In surface sediment in Weishan Lake,the average contents of Cu,Zn,Pb,Cd,Cr and Ni were 64.78,185.05,78.76,0.17,37.76 an...

  14. Testing the potential of 10Be in varved sediments from two lakes for solar activity reconstruction

    Czymzik, Markus; Muscheler, Raimund; Brauer, Achim; Adolphi, Florian; Ott, Florian; Kienel, Ulrike; Dräger, Nadine; Slowinski, Michal; Aldahan, Ala; Possnert, Göran


    The potential of 10Be in annually laminated (varved) lake sediments for solar activity reconstruction is, to date, largely unexplored. It is hypothesized that 10Be contents in sediments from well-chosen lakes reflect the solar induced atmospheric production signal. The varved nature of these archives provides the chance to establish solar activity time-series with very high temporal precision. However, so far solar activity reconstruction from 10Be in varved lake sediments is hampered due to a lack of detailed knowledge of the process chain from production in the atmosphere to deposition on the lake floor. Calibrating 10Be time-series from varved lake sediments against complementary proxy records from the same sediment archive as well as instrumental meteorological and solar activity data will allow a process-based understanding of 10Be deposition in these lakes and a quantitative evaluation of their potential for solar activity reconstruction. 10Be concentration and flux time-series at annual resolution were constructed for the period 1983 to 2007 (approx. solar cycles 22 and 23) conducting accelerator mass spectrometry and varve chronology on varved sediments of Lakes Tiefer See and Czechowski, located on an east-west transect at a distance of about 450 km in the lowlands of northern-central Europe. 10Be concentrations vary between 0.9 and 1.8*108atoms/g, with a mean of 1.3*108atoms/g in Lake Tiefer See and between 0.6 and 1.6*108atoms/g, with a mean of 1*108atoms/g in Lake Czechowski. Calculated mean 10Be flux is 2.3*108atoms/cm2/year for Lake Tiefer See and 0.7*108atoms/cm2/year for Lake Czechowski. Calibrating the 10Be time-series against corresponding geochemical μ-XRF profiles, varve thickness and total organic carbon records as well as precipitation data from the nearby stations Schwerin for Lake Tiefer See and Koscierzyna for Lake Czechowski and a neutron monitor record of solar activity suggests (1) a complex interaction of varying processes influencing

  15. Sediment quality assessment of Beasley Lake: Bioaccumulation and effects of pesticides in Hyalella azteca

    Beasley Lake is a Conservation Evaluation Assessment Program (CEAP) watershed in the intensively cultivated Mississippi Delta, USA. Lake sediment quality at three sites was evaluated in 2004 and 2008 for biological impairment and uptake (viz. body residues) from 14 pesticides and three metabolites ...


    Mining operations have worked the rich mineral resources of the Lake Superior Basin for over 150 years, leaving industrially impacted regions with tailing piles and smelters. In Lake Superior sediments, mercury and copper inventories increase towards shorelines and are highly cor...

  17. Fine sediment dynamics in a shallow lake and implication for design of hydraulic works

    Vijverberg, T.; Winterwerp, J.C.; Aarninkhof, S.G.J.; Drost, H.


    Lake Markermeer is a large (680 km2), shallow body of water in the middle of the Netherlands, with a mean water depth of 3.6 m. One of the major problems in the lake is its decreasing ecological value which is, among other reasons, caused by a gradual increase of suspended sediment concentration and

  18. pH dependent dissolution of sediment aluminum in six Danish lakes treated with aluminum

    Reitzel, Kasper; Jensen, Henning S.; Egemose, Sara


    The possible pH dependent dissolution of aluminum hydroxides (Al(OH)(3)) from lake sediments was studied in six lakes previously treated with Al to bind excess phosphorus (P). Surface sediment was suspended for 2 h in lake water of pH 7.5, 8.5, or 9.5 with resulting stepwise increments in dissolved......H water. Release rates of dissolved Al from intact sediment cores at the same three pH values was measured in three of the lakes, and showed increased Al release rates at pH 8.5 in one of the lakes and 9.5 in two of the lakes. Our study demonstrates a risk of dissolution of sediment Al(OH)(3) to form...... aluminate in shallow lakes, where resuspension and high pH in the water occurs frequently. In the worst case dissolved Al may reach toxic levels in lakes treated by Al but also the concomitant release of P and the possible loss of dissolved Al to downstream ecosystems are negative effects that may occur...


    Mining operations have worked the rich mineral resources of the Lake Superior Basin for over 150 years, leaving industrially impacted regions with tailing piles and smelters. In Lake Superior sediments, mercury and copper inventories increase towards shorelines and are highly cor...

  20. Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects

    Griethuysen, van C.


    This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of

  1. Fine sediment dynamics in a shallow lake and implication for design of hydraulic works

    Vijverberg, T.; Winterwerp, J.C.; Aarninkhof, S.G.J.; Drost, H.


    Lake Markermeer is a large (680 km2), shallow body of water in the middle of the Netherlands, with a mean water depth of 3.6 m. One of the major problems in the lake is its decreasing ecological value which is, among other reasons, caused by a gradual increase of suspended sediment concentration and

  2. Effect of biota on fine sediment transport processes: A study of Lake Markermeer

    De Lucas Pardo, M.A.


    Over the years, Lake Markermeer, formerly a sea arm of the North Sea, has experienced a decline in some of its ecological values. A high suspended sediment concentration in the water column of the lake is believed to be one of the causes of this ecological deterioration. Currently, short term suspen

  3. Diversity of RuBisCO and ATP citrate lyase genes in soda lake sediments

    Kovaleva, O.L.; Tourova, T.P.; Muyzer, G.; Kolganova, T.V.; Sorokin, D.Y.


    Sediments from six soda lakes of the Kulunda Steppe (Altai, Russia) and from hypersaline alkaline lakes of Wadi Natrun (Egypt) were analyzed for the presence of cbb and aclB genes encoding key enzymes Ci assimilation (RuBisCO in Calvin-Benson and ATP citrate lyase in rTCA cycles, respectively). The

  4. Preliminary Report on Unique Laminated Holocene Sediments from the Qarun Lake in Egypt

    Marks Leszek


    Full Text Available The Lake Qarun (Faiyum Oasis, northern Egypt is a relic of the much larger Holocene lake. Past lake levels and extensions were reconstructed, based on setting of archaeological sites scattered along northern paleoshores of the ancient lake. However, geoarcheological works did not yield enough data to establish continuous environmental history of the lake. A deep drilling FA-1 on the southeastern shore of the lake, performed in 2014, supplied with a core, 26 m long that is the one of the longest lake sediment cores in northeastern Africa. The basal section of the core consisted of thin-laminated diatom marly deposits, underlain at the Late Pleistocene/Holocene boundary by coarse-grained sands. The sediment lamine were quite well developed, especially in the lower part of the core. Preliminary results indicated annually deposited sediment sequence with seasonality signals provided by microlamine of diatoms, calcite, organic matter and clastic material. Early Holocene varved sediments from the Faiyum Oasis supplied with exceptional paleoenvironmental data for northeastern Africa, which enriched a record from previous logs drilled at the southwestern margin of the Qarun Lake.

  5. Vertical distributions of PAHs in the sediments of four lakes in Japan

    Fukushima, Takehiko; Watanabe, Seigo; Kamiya, Koichi [Tsukuba Univ., Ibaraki (Japan). Graduate School of Life and Environment; Ozaki, Noriatsu [Hiroshima Univ., Higashihiroshima (Japan). Graduate School of Engineering


    Purpose: The purpose of this study was to elucidate historical trends, spatial variations, and the sources of polycyclic aromatic hydrocarbons (PAHs) pollution in several Japanese lakes. Materials and methods: The vertical distributions of PAHs in the core samples of sediments taken at several points in lakes Kasumigaura, Suwa, Kizaki, and Shinji were determined using a gas chromatograph equipped with a mass selective detector and combined with chronological information and the physical/elemental properties of the sediment. Results and discussion: Seventeen related compounds (congeners) typically had concentration peaks at sediment depths corresponding to the 1960s to 1970s. In Lake Shinji and one bay of Lake Kasumigaura, there was a tendency for PAH concentrations to increase downstream; in contrast, another bay of Lake Kasumigaura showed the reverse trend. During big flood events, the fluxes of PAHs increased due to large inputs of particulate matter, although PAH concentrations were reduced. For the four study lakes and other similar lakes, PAH concentrations of surface sediments were approximately proportional to population densities in the respective watersheds, while the total input of PAHs to the lakes were correlated with their population and watershed area. The source apportionment analysis using isomer ratios for the congener profiles indicated that the principal sources of the PAHs in the lake sediments were gasoline and/or diesel engine exhausts and biomass burning. Conclusions: The observed concentration peaks showed a deterioration of the chemical quality of atmospheric conditions around 1960-1970 and a recent tendency for their amelioration. Between-lake differences suggest that the influence of human activity in the watersheds influences sediment PAH concentrations. The PAH sources were identified to be of pyrogenic origin. (orig.)

  6. Assessment of Bathymetry and Sediment Accumulation of Walker Lake, PA with Multiple Frequency GPR Antennas

    Lachhab, A.; Booterbaugh, A.; Beren, M.


    Silting within all man-made reservoirs, can be a major problem. Exploring bathymetry with electromagnetic prospection tools is one way to identify the magnitude of sediment accumulation in lakes and reservoirs. In this study, the bathymetry and sediment accumulation of Walker Lake, PA was explored via multi-frequency ground penetrating radar (GPR) surveys. Walker Lake is located on the North Branch Middle Creek, which is a tributary to Middle Creek within the Susquehanna River basin. The technique developed in this study included two antennas positioned on a medium size inflatable boat towed by a 14' flat-bottom Jon Boat. Both 400 and 100 MHz antennas were deployed and sediment thickness and distribution throughout the lake were identified. A total of eighteen transects were taken along the entire length of the lake. A new method with multiple approaches including RADAN 7, GPR Viewer, SAS 9.1.3 and MATLAB was developed to generate three-Dimensional and contour surface of the pre-1971 Topography and bathymetry based on GPR reflection readings. As a result, depth, accumulation and rate of sedimentation in the lake were successfully measured. The lake was found to vary between 0.5 to 9 meters in depth. Sediment accumulation and distribution were calculated from the difference between the surveyed bathymetry and the 1971 pre-existent landscape topography. Sediment was found to accumulate thickest within the old channel of Middle Creek however, the bulk of the sediment volume lied outside this channel. Sediment deposition accumulates mainly upstream near the inlet to the lake and gradually decreases toward the dam inversely proportional to the depth of the lake.

  7. Historical profiles of PCB in dated sediment cores suggest recent lake contamination through the "halo effect".

    Naffrechoux, Emmanuel; Cottin, Nathalie; Pignol, Cécile; Arnaud, Fabien; Jenny, Jean-Philippe; Perga, Marie-Elodie


    We investigated the major sources of polychlorinated biphenyls (PCB) and interpreted the environmental fate processes of these persistent organic pollutants in the past and current PCB contamination of three large, urbanized, French peri-alpine lakes. Dated sediment cores were analyzed in order to reconstruct and compare the historical contamination in all three lakes. Stratigraphic changes of PCB contents and fluxes were considered as revealing the temporal dynamics of PCB deposition to the lakes and the distribution of the seven indicator congeners (further referred to as PCBi) as an indicator of the main contamination origin and pathway. Although located within a single PCB industrial production region, concentration profiles for the three lakes differed in timing, peak concentration magnitudes, and in the PCBi congeners compositions. PCBi fluxes to the sediment and the magnitude of the temporal changes were generally much lower in Lake Annecy (0.05-2 ng·cm(-2)·yr(-1)) as compared to Lakes Geneva (0.05-5 ng·cm(-2)·yr(-1)) and Bourget (5-290 ng·cm(-2)·yr(-1)). For all three lakes, the paramount contamination occurred in the early 1970s. In Lakes Annecy and Bourget, PCB fluxes have declined and plateaued at 0.5 and 8 ng·cm(-2)·yr(-1), respectively, since the early 1990s. In Lake Geneva, PCB fluxes have further decreased by the end of the XX(th) century and are now very low. For the most contaminated lake (Lake Bourget), the high PCBi flux (5-290 ng·cm(-2)·yr(-1)) and the predominance of heavy congeners for most of the time period are consistent with a huge local input to the lake. This still high rate of Lake Bourget is explained by transport of suspended solids from one of its affluents, polluted by an industrial point source. Intermediate historical levels and PCBi distribution over time for Lake Geneva suggest a mixed contamination (urban point sources and distant atmospheric transport), while atmospheric deposition to Lake Annecy explains its lowest

  8. Distribution and Variation of Ribonucleic Acid (RNA) and Protein and Its Hydrolysis Products in Lake Sediments

    梁小兵; 万国江; 黄荣贵


    Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition-amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein.The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities.

  9. Isopach Map of Postimpoundment Sediment in Lake Mead - Geographic Coordinates

    U.S. Geological Survey, Department of the Interior — Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction...

  10. Shapefile of the postimpoundment sediment limits in Lake Mead

    U.S. Geological Survey, Department of the Interior — Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction...

  11. Isopach Map of Postimpoundment Sediment in Lake Mead - Geographic Coordinates

    U.S. Geological Survey, Department of the Interior — Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction...

  12. Identification of greigite in lake sediments and its magnetic significance

    HU; Shouyun


    [1]Xue, B., Wang, S., Xia, W. et al., The uplift and environmental change of Qinghai-Xizang (Tibetan) Plateau in the past 0.9 Ma inferred from Core RM in Zoigê Basin, Science in China, Ser. D, 1998, 41(2): 165-170.[2]Hoffmann, V., Greigite (Fe3S4): magnetic properties and first domain observations, Phys. Earth Planet Inter., 1992, 70: 288-301.[3]Snowball, I., Thompson, R., A stable chemical remanence in Holocene sediments, J. Geophys. Res., 1990, 95: 4471-4479.[4]Dekkers, M. J., Magnetic properties of natural pyrrhotite, II: High- and low-temperature behaviour of Jrs and TRM as function of grain size, Phys. Earth Planet Inter., 1989, 57: 266-283.[5]Rochette, P., Fillion, G., Mattéi, J. L. et al., Magnetic transition at 30 - 234 K in pyrrhotite: insight into a widespread occurrence of this mineral in rocks, Earth Planet Sci. Lett., 1990, 98: 319-328.[6]McCabe, C., Channell, J. E. T., Late Paleozoic remagnetization in limestones of the Craven Basin (northern England) and the rock magnetic fingerprint of remagnetized sedimentary carbonates, J. Geophys. Res., 1994, 99: 4603-4612.[7]Snyder, R. L., Analytical profile fitting of X-ray powder diffraction profiles in Rietveld analysis, in The Rietveld Method (ed., R. A. Young), Oxford: Oxford University Press, 1995, 111-131.[8]Klug, H. P., Alexander, L. E., X-ray Diffraction Procedures for Polycrystalline and Amorphous Materials, New York: Illus. John Wiley & Sons, 1954, 97.[9]Diaz, I. J. C., Kirschvink, L., Magnetic domain state and coercivity predictions for biogenic greigite (Fe3S4): A comparison of theory with magnetosome observations, J. Geophys. Res., 1992, 97: 309-315.[10]Snowball, I., Thompson, R., The occurrence of greigite in sediments from Loch Lomond, J. Quatern. Sci., 1988, 3: 121-125.[11]Ariztegui, D., Dobson, J., Magnetic investigations of framboidal greigite formation; a record of anthropogenic environmental changes in eutrophic Lake St. Moritz, Switzerland, The

  13. Modeling of sediment and heavy metal transport in Taihu Lake, China

    WANG Chao; SHEN Chao; WANG Pei-fang; QIAN Jin; HOU Jun; LIU Jia-jia


    With the current rapid economic growth,heavy metal pollution has become one of the key issues in the Taihu Lake.Although heavy metal pollution levels and distributions of the Taihu Lake have previously been described,an effective model to describe the transport process of heavy metals between the water column and sediment bed for this lake is not available.It is known that heavy metals in the water column can be related to the resuspension of sediment in the lake bed.In this study,we set up a coupled model of relating hydrodynamics,sediment and heavy metals based on Environmental Fluid Dynamics Code (EFDC),and applied it to Taihu Lake,China.For calibration and validation of the model,we employed two series of field sampling data taken all over Taihu Lake during April and July of 2009.The results show that the hydrodynamics simulations of the coupled model agree with the observations reasonably well and the sediment and heavy metal model shows similar variation trends during the simulation.Our results indicate that the model can be used for simulating the sediment and heavy metal transport process in the Taihu Lake and here we provide an effective tool for water quality management at small time scales.

  14. Electricity generation by anaerobic bacteria and anoxic sediments from hypersaline soda lakes

    Miller, L.G.; Oremland, R.S.


    Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However, these cultures grew equally well without added arsenate using the MFC anode as their electron acceptor, and in the process oxidized lactate more efficiently. The decrease in electricity generation by consumption of added alternative electron acceptors (i.e. arsenate) which competed with the anode for available electrons proved to be a useful indicator of microbial activity and hence life in the fuel cells. Shaken sediment slurries from these two lakes also generated electricity, with or without added lactate. Hydrogen added to sediment slurries was consumed but did not stimulate electricity production. Finally, electricity was generated in statically incubated "intact" sediment cores from these lakes. More power was produced in sediment from Mono Lake than from Searles Lake, however microbial fuel cells could detect low levels of metabolism operating under moderate and extreme conditions of salt stress. ?? 2008 US Government.

  15. Application of a comprehensive extraction technique for the determination of poly- and perfluoroalkyl substances (PFASs) in Great Lakes Region sediments.

    Guo, Rui; Megson, David; Myers, Anne L; Helm, Paul A; Marvin, Chris; Crozier, Patrick; Mabury, Scott; Bhavsar, Satyendra P; Tomy, Gregg; Simcik, Matt; McCarry, Brian; Reiner, Eric J


    A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.1 ng/g), where perfluorooctane sulfonic acid (PFOS) contributed over 80% of the total. Concentrations in Lake Ontario were approximately 1-2 orders of magnitude greater than the more remote lakes subject to primarily atmospheric inputs. Whilst the PFAS contribution in Lake Ontario was dominated by PFOS, the more remote lakes contained sediment with higher proportions of PFCAs. Trace amounts of emerging PFASs (diPAPs and PFPiAs) were found in very recent surface Lake Ontario and remote lake sediments.

  16. Characterization of Sedimentation and Its Impacts at Big Lake National Wildlife Refuge, Manila, AR

    US Fish and Wildlife Service, Department of the Interior — This report provides the results of an investigation to examine the sedimentation loading into Big Lake associated with high flow events. The goal of this study was...

  17. Environmental contaminants in water, sediment and biological samples from Playa Lakes in southeastern New Mexico - 1992

    US Fish and Wildlife Service, Department of the Interior — Sediment, water, bird tissue, and invertebrates were collected from 10 playa lakes in Southeastern New Mexico in 1991 and 1992. These samples were analyzed for a...

  18. Total and methyl mercury, moisture, and porosity in Lake Michigan surficial sediment

    U.S. Environmental Protection Agency — Total and methyl mercury, moisture content (%), and porosity were measured in Lake Michigan sediment by the U.S. Environmental Protection Agency/Office of Research...

  19. Computer simulation of phosphorus cycling in the sediment-water system of eutrophic lakes

    Hannula, T.A.; Rock, C.A.


    It has become increasingly evident that the release of phosphorus from the sediments of eutrophic lakes is a major factor in the excessive productivity of these lakes. Using the diagenic partial differential equations which model the sediment processes of lakes and oceans, a computer simulation model has been developed to study the P dynamics in lake sediments. The model allows both time and depth variation of the key equation parameters. The model clearly shows that the upper 10 cm of sediment is the main region of activity. The model generates summary tables and 3D plots of key variables over a year's simulation. Data from L. Sebasticook, Newport, Maine are used to test the model.

  20. Sedimentation Survey Report: South Unit, Lake Andes, Charles Mix County, South Dakota.

    US Fish and Wildlife Service, Department of the Interior — This report addresses the procedures used to obtain sediment data, how they analyzed the data, and the potential restoration alternatives for Lake Andes. The purpose...

  1. Jellyfish Lake, Palau: Regeneration of C, N, Si, and P in anoxic marine lake sediments

    Lyons, W.B.; Lent, R.M.; Burnett, W.C.; Chin, P.; Landing, W.M.; Orem, W.H.; McArthur, J.M.


    Sediment cores from Jellyfish Lake were processed under an inert atmosphere and the pore waters extracted and analyzed for the following parameters: pH, titration alkalinity (TA), Cl-, H4SiO4, PO43-, NH4+, Ca2-, Mg2+, SO42-, and H2S. Additionally, in one set of pore-water samples (core 10), the ??13C of the ??CO2 was also determined. The TA, H4SiO4, PO43-, NH4+, and H2S increased with depth in the pore waters above anoxic bottom-water values. H2S values increased to 3.8 ??M. In one case, both H4SiO4 and PO43- concentrations increased to a maximum value and then decreased with depth, suggesting removal into solid phases. The H4SiO4 concentrations are equal to or greater than pore-water values observed in sediments underlying upwelling areas. PO43- concentrations are, in general, lower than pore-water values from terrigenous nearshore areas but higher than nearshore carbonate pore-water values from Florida Bay or Bermuda. The Ca2+, Cl-, and Mg2+: Cl- ratios show slight decreases in the top 15-20 cm, suggesting that authigenic carbonate may be forming. This suggestion is supported by the fact that the pore waters are saturated with respect to CaCO3 due to the very high TAs. The ??13C measurements of the pore-water ??CO2 are from a shorter core. These measurements reach their most negative concentration at 72 cm and then become slightly heavier. This change is accompanied by a decrease in TA, suggesting the onset of methanogenesis at this location in this core.

  2. Matuyama/Brunhes Polarity Transition in Owens Lake, CA, Sediment

    Liddicoat, Joseph; Kravchinsky, Vadim


    The complexity of the Matuyama/Brunhes (M/B) polarity transition is becoming better understood from investigations of volcanic rocks (Coe et al., 2004), loess (Jin et al., 2012; Evans et al., 2011; Kravchinsky, 2013), and marine (Clement and Opdyke, 1982; Hartl and Tauxe, 1996; Macri et al., 2010) and lacustrine (Valet et al., 1988; Sagnotti et al., 2013) sediments. The transition appears to include a brief interval of normal polarity prior to the entry into the Brunhes Normal Chron (Coe et al., 2004; Jin et al., 2012; Evans et al., 2011), and the transition has Virtual Geomagnetic Poles rapidly moving from the Southern Hemisphere to the Northern Hemisphere (Coe et al., 2004; Jin et al., 2012; Evans et al., 2011; Sagnotti et al., 2013). The M/B polarity transition is recorded in exposed Pleistocene lake sediments near Bishop, CA, where the brief interval of normal polarity noted above is present and the change from full reverse to full normal polarity occurs rapidly. The brief interval of normal polarity is recorded at two sites separated laterally by about 150 m and is in single hand samples measured at vertical spacing of 2.0-2.5 cm using six samples per measured level and alternating field demagnetization at 20 mT (Liddicoat, 1993, Table 1 and Fig. 8). The siltstone is unweathered glacial flour from the Sierra Nevada that borders the western side of Owens Valley where the sediments were deposited in Owens Lake. In the siltstone, the majority of the samples have a percentage of about 60 percent where the grain diameter is less than 63 micrometres, and in those samples there is about a five percent fraction when the diameter is two micrometres or less. The Total Inorganic Carbon in most samples is about 0.25 percent (Bergeron, 2013), and magnetite is the dominant carrier of the magnetization (Liddicoat, 1993). The palaeomagnetic directions recording the terminus of the full M/B transition, which occurs before the field intensity is completely recovered, spans no

  3. Hydrological reconstruction from tree rings and varved lake sediments

    Fortin, D.; Nicault, A.; Francus, P.; Bégin, Y.; Perreault, L.; Arsenault, D.; Bégin, C.; Savard, M. M.; Marion, J.; Guiot, J.


    The ARCHIVES project aims at reconstructing the annual hydro-climatic variability of the boreal region of the Quebec-Labrador Peninsula (Canada) over the past millennia. The project is based on tree-ring chronologies of more than one hundred years-old black spruce stands, several millennial tree-ring chronologies developed from sub-fossil trees and a network of lake sediment cores over a territory of more than 700 000 km2 (1400km in longitude x 500km in latitude). The dendrochronological network includes various tree-ring proxies such as ring width, ring density and ∂13C and ∂18O series. An extensive search for annually laminated lakes in the area permitted the identification of several sites with a strong potential for hydro-climatic reconstitution using annual varve thickness, grain size variability and sub-annual lamination as proxies for changes in river competency. We present here a 300 years-long reconstruction of hydrological variables at the watershed scale (annual water supply, spring and summer runoff) and some climate variables used in hydrologic forecast models, including an atmospheric index used by the modelling team of Hydro-Quebec (hydroelectric power supplier) to forecast spring flood volumes using both tree rings and annually laminated sediments. The sensitivity of the tree-ring chronologies and of varved series to hydrologic parameters were tested using statistical response functions. Our reconstruction methodology combines an analogue technique for the estimation of missing tree-ring data with an artificial neural network for optimal nonlinear calibration, including a bootstrap error assessment. Transfer functions were calibrated with water supply and meteorological data provided by Hydro-Quebec, and with Climate Research Unit (CRU) gridded climate data. The reconstructed series were validated using Reduction error (RE) and Root mean square error (RMSE) coefficients, standard cross-validation tests and verified with independent instrumental

  4. Elemental composition of a deep sediment core from Lake Stocksjoen in the Forsmark area

    Stroemgren, Maarten [Umeaa Univ. (Sweden). Dept. of Ecology and Environmental Sciences; Brunberg, Anna-Kristina [Uppsala Univ. (Sweden). Dept. of Ecology and Evolution/Limnology


    A deep sediment core was taken from Lake Stocksjoen, situated within the Forsmark site investigation area. The 55 cm long sediment core, representing the entire history of the lake (approx 430 years) was sliced in 5 cm portions and analysed for various chemical elements, using ICP-MS technique. In total, 54 different elements - classified as main elements, heavy metals and trace elements - were analysed. In general terms, three different patterns of stratigraphy were derived from all the analysed elements. Calcium, manganese, lead and mercury occurred in highest concentrations in the upper sediments (<30 cm depth). Phosphorus, zinc, cadmium, antimony, tin and strontium occurred in more even proportions throughout the sediment core. All the other elements were substantially reduced in the upper parts (<30 cm) compared to the deeper parts of the sediment core. Metals that are considered as airborne pollutants were found in low or moderate concentrations. This is in concert with other investigations of pollutants that have been performed in the Forsmark area. The sediment of Lake Stocksjoen is highly organic, and has been so during the entire history of the lake. Much of the organic Material seems to be refractory and less susceptible for mineralisation and respiration during the prevailing environmental conditions. This corresponds well with the characteristic gelatinous cyanophycee gyttja found in the lower parts of the sediment core. Although speculative, the pronounced changes in elemental composition of the sediment at 30 cm depth may correspond to the final isolation of the lake from the Baltic Sea, which occurred approximately 230 years ago. The deeper parts (below 30 cm depth) thus may represent the time period with regular intrusions of brackish water into the lake basin. One important factor governing the environmental conditions and the resulting elemental composition of the sediment is the unusually thick 'microbial mat', which is characteristic

  5. Isotopic and hydrologic responses of small, closed lakes to climate variability: Comparison of measured and modeled lake level and sediment core oxygen isotope records

    Steinman, Byron A.; Abbott, Mark B.; Nelson, Daniel B.; Stansell, Nathan D.; Finney, Bruce P.; Bain, Daniel J.; Rosenmeier, Michael F.


    Simulations conducted using a coupled lake-catchment isotope mass balance model forced with continuous precipitation, temperature, and relative humidity data successfully reproduce (within uncertainty limits) long-term (i.e., multidecadal) trends in reconstructed lake surface elevations and sediment core oxygen isotope (δ18O) values at Castor Lake and Scanlon Lake, north-central Washington. Error inherent in sediment core dating methods and uncertainty in climate data contribute to differences in model reconstructed and measured short-term (i.e., sub-decadal) sediment (i.e., endogenic and/or biogenic carbonate) δ18O values, suggesting that model isotopic performance over sub-decadal time periods cannot be successfully investigated without better constrained climate data and sediment core chronologies. Model reconstructions of past lake surface elevations are consistent with estimates obtained from aerial photography. Simulation results suggest that precipitation is the strongest control on lake isotopic and hydrologic dynamics, with secondary influence by temperature and relative humidity. This model validation exercise demonstrates that lake-catchment oxygen isotope mass balance models forced with instrumental climate data can reproduce lake hydrologic and isotopic variability over multidecadal (or longer) timescales, and therefore, that such models could potentially be used for quantitative investigations of paleo-lake responses to hydroclimatic change.

  6. Lake trout in northern Lake Huron spawn on submerged drumlins

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.


    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  7. Sediment Dynamics in a Vegetated Tidally Influenced Interdistributary Island: Wax Lake, Louisiana


    ER D C/ CH L TR -1 7- 12 Sediment Dynamics in a Vegetated Tidally Influenced Interdistributary Island: Wax Lake, Louisiana Co as ta l... a nd H yd ra ul ic s La bo ra to ry Richard Styles, Duncan Bryant, Joe Gailani, Jarrell Smith, Brandon M. Boyd, and Greg Snedden July 2017...client/default. ERDC/CHL TR-17-12 July 2017 Sediment Dynamics in a Vegetated Tidally Influenced Interdistributary Island: Wax Lake, Louisiana

  8. Strong magnetic levels in Lake Chapala sediments (western Mexico) : their mineralogy and stratigraphic significance

    Michaud, François; Ramirez Sanchez, H.U.; Parron, C.; Zarate del Valle, P.F.; Fernex, F.; Barci Funel, G.


    Lake Chapala, located 120 km northeast of Colima Volcano, lies at the north and northeast of the Citala rift in the Trans-Mexican Volcanic Belt. It belongs to the watershed of the Lerma River, which originates from the Mexico City area, 450 km to the east. Sediment cores, 0.5-2 m long, were collected from the lake. Magnetic susceptibility of the lake sediments generally ranges from 400 to 800 x 10(-9) m(3) kg(-1); but in some layers it exceeds 1000 or 1500 x 10(-9) m(3) kg(-1). The magnetic s...

  9. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

    Li, Hong-Bo [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yu, Shen, E-mail: [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Li, Gui-Lin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Liu, Yi; Yu, Guang-Bin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Deng, Hong [Department of Environmental Sciences, Tiantong National Station of Forest Ecosystem, Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai 200062 (China); Wu, Sheng-Chun [State Key Laboratory in Marine Pollution, Biology and Chemistry Department, City University of Hong Kong, Hong Kong (China); Wong, Ming-Hung [Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong (China)


    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 {mu}m) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: Black-Right-Pointing-Pointer Obvious

  10. Spatial variability of recent sedimentation in Lake Ohrid (Albania/Macedonia

    H. Vogel


    Full Text Available Lake Ohrid is likely of Pliocene age and thus commonly referred to as the oldest existing lake in Europe. In this study spatial variability of recent sediment composition is assessed using >50 basin wide distributed surface sediment samples. Analysis of biogeochemical bulk parameters, selected metals, pigment concentrations as well as grain size distributions revealed a significant spatial heterogeneity in surface sediment composition. It implies that sedimentation in Lake Ohrid is controlled by an interaction of multiple natural and anthropogenic factors and processes. Major factors controlling surface sediment composition are related to differences in geological catchment characteristics, anthropogenic land use, and a counterclockwise rotating surface water current. In some instances processes controlling sediment composition also seem to impact distribution patterns of biodiversity, which suggests a common interaction of processes responsible for both patterns.

  11. Quantitative spatiotemporal characterization of methane venting from lake sediments

    Scandella, B.; Pillsbury, L.; Weber, T.; Ruppel, C. D.; Hemond, H.; Juanes, R.


    Methane is a potent greenhouse gas, and the production and emission of methane from sediments in inland waters and shallow oceans both contributes to and may be exacerbated by climate change. In some of these shallow-water settings, methane fluxes are often controlled by episodic free-gas venting. The fraction of the methane released from the sediments that bypasses dissolution in the water column and reaches the atmosphere impacts the magnitude of the climate forcing, and this fraction depends critically on the mode and spatiotemporal characteristics of the bubble releases. The spacing and persistence of the gas vents may be determined by the heterogeneity of the methane source, but within regions of uniform methanogenesis they arise from the competition between mechanisms driving lateral and vertical transport of methane in the sediments. Here, we present measurements of the spacing, persistence and variability in intensity of methane vents within a wide area of lake sediments (~400 m2) and over a multi-month period. The measurements were made using a fixed-location Imagenex DeltaT 837B multibeam sonar, which was calibrated to quantify gas fluxes with unprecedented spatial and temporal resolution (~0.5 m, 6 Hz). Drops in hydrostatic pressure were a characteristic trigger for the sonar-detected ebullition events, and the episodicity of the fluxes is reproduced with a mechanistic numerical model of methane venting through dynamic conduits that dilate in response to hydrostatic unloading. The spatial characteristics of the sonar-detected vents inform conceptual and mathematical models of methane transport and release from deformable sediments, as well as the uncertainty associated with upscaling. Taken together, these results point towards a better understanding of the microscale processes controlling methane venting from deformable sediments, as well as their impact on large-scale methane fluxes from shallow-water bodies. Figure: Top: time series of daily sonar

  12. Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu).

    Kang, Lei; Wang, Qing-Mei; He, Qi-Shuang; He, Wei; Liu, Wen-Xiu; Kong, Xiang-Zhen; Yang, Bin; Yang, Chen; Jiang, Yu-Jiao; Xu, Fu-Liu


    The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph-mass spectrometer (GC-MS). The temporal-spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146 ± 2.255 μg/g dw) was lower than that in the western core sediments (10.615 ± 9.733 μg/g) and in the eastern core sediments (5.109 ± 4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128 ± 1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323 ± 0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.

  13. Spatiotemporal patterns of mercury accumulation in lake sediments of western North America.

    Drevnick, Paul E; Cooke, Colin A; Barraza, Daniella; Blais, Jules M; Coale, Kenneth H; Cumming, Brian F; Curtis, Chris J; Das, Biplob; Donahue, William F; Eagles-Smith, Collin A; Engstrom, Daniel R; Fitzgerald, William F; Furl, Chad V; Gray, John E; Hall, Roland I; Jackson, Togwell A; Laird, Kathleen R; Lockhart, W Lyle; Macdonald, Robie W; Mast, M Alisa; Mathieu, Callie; Muir, Derek C G; Outridge, Peter M; Reinemann, Scott A; Rothenberg, Sarah E; Ruiz-Fernández, Ana Carolina; Louis, Vincent L St; Sanders, Rhea D; Sanei, Hamed; Skierszkan, Elliott K; Van Metre, Peter C; Veverica, Timothy J; Wiklund, Johan A; Wolfe, Brent B


    For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2μg/m(2) per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of "legacy" mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

  14. Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

    Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.


    For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, <1% of mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

  15. Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic: levels, sources and fluxes.

    Jiao, Liping; Zheng, Gene J; Minh, Tu Binh; Richardson, Bruce; Chen, Liqi; Zhang, Yuanhui; Yeung, Leo W; Lam, James C W; Yang, Xulin; Lam, Paul K S; Wong, Ming H


    Surface sediments from remote lakes and coastal areas from Ny-Alesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Alesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Alesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.

  16. Upper Klamath basin nutrient-loading study: Estimate of wind-induced resuspension of bed sediment during periods of low lake elevation

    Laenen, Antonius; LeTourneau, A.P.


    At low lake elevations for Upper Klamath Lake (below 4,140 feet, Bureau of Reclamation datum), 75 percent or more of the areal extent of the lake is affected by resuspension of bed sediment, under prevailing summer wind conditions when critical water quality conditions occur. At the minimum lake elevation of 4,137 feet, 89 percent of the lake is affected.

  17. Heavy metals in sediments of a large, turbid tropical lake affected by anthropogenic discharges

    Rosales-Hoz, L.; Carranza-Edwards, A.; Lopez-Hernandez, M. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias del Mar y Limnologia


    Bottom-water data and trace metal concentration of Cu, Cr, Ni, Pb, Co, Zn, and organic matter in surficial sediment samples from 13 sampling stations of Lake Chapala in Mexico were studied. The lake is turbid with a great amount of flocculated sediments as a result of wind mixing, sediment re-suspension, and Lerma River discharges. Al distribution pattern in sediments was used as an indicator of the Lerma River discharges into Lake Chapala. The highest values of Cu (33.27 ppm), Cr (81.94 ppm), Pb (99.8 ppm), and Zn (149.7 ppm) were detected in sediments near the lake outlet. The bioavailable metal fraction is low for all metals except Pb, which shows 65-93% of the total metal concentration in bioavailable form. The minimum energy zone in the lake was related to organic matter concentration and was located in the SE part of the lake. An analysis of the studied parameters shows two zones: eastern zone (fluvio-deltaic) and central-western zone (lacustrine). (orig.)

  18. Paleomagnetic secular variation and environmental magnetism of Holocene-age sediments from Tulare Lake, CA

    Roza, Janine; Jackson, Brandon; Heaton, Eric; Negrini, Rob


    The lake-level record from Tulare Lake, CA has been shown to provide valuable constraints on late Pleistocene and Holocene runoff from the Sierra Nevada mountain range into the San Joaquin Valley of California, one of the world's most prolific agricultural centers. This project uses the magnetic properties of the Tulare Lake sediments in order to date the sediments and to constrain the relative lake level at the time of deposition. Shallowing lake conditions were identified leading up to a prominent unconformity; magnetic mineralogy and grain size indicators, primarily decreasing ARM/IRM and S-Ratio values suggest coarser grain sizes and more oxidizing conditions. Approximately half of the samples possessed well-behaved paleomagnetic directions suitable for paleomagnetic secular variation dating. The results indicate that the sediments below the unconformity were deposited approximately 7600-8500 cal yr BP, and the sediments above the unconformity were deposited approximately 2500-800 cal yr BP. The ages of the corresponding sediments are consistent with the time intervals during which previous studies indicate that lake level was above the elevation of this site, before and after a mid Holocene regression.

  19. Using lead isotopes and trace element records from two contrasting Lake Tanganyika sediment cores to assess watershed – Lake exchange

    Odigie, Kingsley; Cohen, A.D.; Swarzenski, Peter W.; Flegal, R


    Lead isotopic and trace element records of two contrasting sediment cores were examined to reconstruct historic, industrial contaminant inputs to Lake Tanganyika, Africa. Observed fluxes of Co, Cu, Mn, Ni, Pb, and Zn in age-dated sediments collected from the lake varied both spatially and temporally over the past two to four centuries. The fluxes of trace elements were lower (up to 10-fold) at a mid-lake site (MC1) than at a nearshore site (LT-98-58), which is directly downstream from the Kahama and Nyasanga River watersheds and adjacent to the relatively pristine Gombe Stream National Park. Trace element fluxes at that nearshore site did not measurably change over the last two centuries (1815–1998), while the distal, mid-lake site exhibited substantial changes in the fluxes of trace elements – likely caused by changes in land use – over that period. For example, the flux of Pb increased by ∼300% from 1871 to 1991. That apparent accelerated weathering and detrital mobilization of lithogenic trace elements was further evidenced by (i) positive correlations (r = 0.77–0.99, p < 0.05) between the fluxes of Co, Cu, Mn, Ni, Pb, and Zn and those of iron (Fe) at both sites, (ii) positive correlations (r = 0.82–0.98, p < 0.01, n = 9) between the fluxes of elements (Al, Co, Cu, Fe, Mn, Ni, Pb, and Zn) and the mass accumulation rates at the offshore site, (iii) the low enrichment factors (EF < 5) of those trace elements, and (iv) the temporal consistencies of the isotopic composition of Pb in the sediment. These measurements indicate that accelerated weathering, rather than industrialization, accounts for most of the increases in trace element fluxes to Lake Tanganyika in spite of the development of mining and smelting operations within the lake’s watershed over the past century. The data also indicate that the mid-lake site is a much more sensitive and useful recorder of environmental changes than the nearshore site. Furthermore, the lead isotopic compositions

  20. Chemical and mineralogical proxies of erosion episodes in the dried lake sediments (Amik Lake, Southern Turkey): paleoenvironmental implications

    El Ouahabi, Meriam; Hubert-Ferrari, Aurélia; Lebeau, Héléne; Fagel, Nathalie; Vander Auwera, Jacquelinec; Karabacak, Volkan; Schmidt, Sabine


    The Amik Basin in the Eastern Mediterranean region has been continuously occupied since 6000-7000 BC. The landscape has sustained with highly variable anthropic pressure culminating during the Late Roman Period when the Antioch city reached its golden age. The basin also sustained a high seismic activity (M≥7) as it is a releasing step-over along the Dead Sea Fault. The study focuses on the sedimentary record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major paleo-environmental changes in the area over the last 4000 years and to unravel possible human impacts on the sedimentation. A diverse array of complementary methods was applied on the 6 m long record. High resolution of mineralogical (XRD) and geochemical (XRF) analyses were performed. Quantitative mineralogical phases of sediments by the Rietveld method were computed using Topaz software. The age of the record is constrained combining radionuclide and radiocarbon dating, and checked using the correlation between the earthquake history and rapidly deposited layer identified. A high sedimentation rate of 0.12 cm/yr was inferred at the coring site. The 4000 years old record shows that significant fluctuations of the lake level and the riverine system inflow into the Amik Lake occurred. The Late Bronze lowstand leaded to punctual dryings of the lake at the end of the Bronze/Iron transition marked by the collapse of the Hittite Empire and during the Dark ages. At that time, the riverine was carrying a large terrigenous input linked to strong soil erosion related to deforestation, exploitation of mineral resources and the beginning of upland cultivation. During the Roman Period and in the later periods, upland soils were partly depleted and the riverine system completely transformed by channelization that leaded to a mashification of the Amik Basin. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation

  1. Archaeal and bacterial community structures in the anoxic sediment of Antarctic meromictic lake Nurume-Ike

    Kurosawa, Norio; Sato, Shota; Kawarabayasi, Yutaka; Imura, Satoshi; Naganuma, Takeshi


    Prokaryotic community structures in the anoxic sediment of the Antarctic meromictic Lake Nurume-Ike were revealed by sequence analysis of 16S rRNA gene clones. The archaeal clones obtained (205 total) consisted of only three phylotypes, and were dominantly affiliated with uncultured euryarchaeotes. Specifically, 93% of the clones were identified as marine benthic group-D archaeal phylotype. In contrast to the limited archaeal diversity, 53 phylotypes were detected within 312 bacterial clones. Major bacterial phylotypes were affiliated with α-Proteobacteria (20% of clones), d-Proteobacteria (9%), Planctmycetales (7%), and Cyanobacteria (7%). A small numbers of clones belonging to γ-Proteobacteria, Actinobacteria, Spirochaetes, Flavobacteria, and Verrucomicrobia were also found. A total of 53% of the bacterial clones, consisting of 13 phylotypes, could not be classified into any known group. These results indicated that the bacterial community of Lake Nurume-Ike sediment consisted of numerous phylogenetic groups and had a diversity comparable to the diversity of other Antarctic lakes communities previously reported. Interestingly, however, there were very few phylotypes shared between the communities of lakes Nurume-Ike and five other lakes located in the Vestfold Hills area. This is the first comprehensive study to analyze more than 500 16S rDNA clones for microbial community analysis of an Antarctic lake sediment sample, and the results significantly expand current views of bacterial diversity in Antarctic lakes.

  2. Immunoassay screening of sediment cores for polychlorinated biphenyls, Devil's Swamp Lake near Baton Rouge, Louisiana, 2004

    Van Metre, Peter C.; Wilson, Jennifer T.


    Devil?s Swamp Lake near Baton Rouge, Louisiana, constructed by dredging in 1973 in Devil?s Swamp along the Mississippi River, is contaminated with polychlorinated biphenyls (PCBs). This study investigated the possible historical contribution of PCBs from a hazardous-chemical disposal facility by way of a wastewater drainage ditch that operated from 1971 to 1993. Six sediment cores from the lake and three bottom-material samples from the drainage ditch were collected on October 5, 2004, and analyzed for PCBs using an immunoassay screening method. The results were used to evaluate qualitatively the historical input record of PCBs to the lake. Deposition dates in three of the cores were estimated by assuming that penetration of the push corer was stopped by firmer, pre-lake materials that mark the 1973 subsurface level of dredging. Sixty-one samples from five of the six cores and three bottom-material samples from the drainage ditch were analyzed. PCBs were at higher concentrations in ditch bottom material (about 1.1 to 2.2 milligrams per kilogram) than in cores from sites near where the ditch enters the lake (about 0.1 to 1.0 milligrams per kilogram). The highest concentrations of PCBs (maximum about 15 milligrams per kilogram) were detected in lake-bottom sediment about 350 meters west of where the drainage ditch enters the lake. Detection rates and median PCB concentrations were higher in all of the dated core sediments deposited before about 1990 than after 1990.

  3. Deltaic sedimentation in saline, alkaline Lake Bogoria, Kenya: Response to environmental change

    Renaut, R.W. (Univ. of Saskatchewan, Saskatoon (Canada). Dept. of Geological Sciences); Tiercelin, J.J. (Univ. Bretagne Occidentale, Brest (France). Domaines Oceaniques)


    Lake Bogoria is a meromictic, saline (90 g/l TDS), alkaline (pH: 10.3) lake with Na-CO[sub 3]-Cl waters, located in a narrow half-graben in the central Kenya Rift. It is fed by hot springs, direct precipitation, and a series of ephemeral streams that discharge into the lake via small deltas and fan-deltas. Examination of the exposed deltas and >50 short cores from the lake floor, have revealed a wide range of deltaic and prodeltaic sediments, including turbidites and subaqueous debris-flow deposits. Studies of 3 long cores and the exposed delta stratigraphy have shown how the style of deltaic sedimentation has responded to environmental changes during the last 30,000 years. During humid periods when lake level is high the lake waters are fresher and less dense. Theoretically, high sediment yield and more constant discharge may promote underflow (hyperpycnal flow), generating low-density turbidity currents. In contrast, during low stages with dense brine, the less dense, inflowing waters carry fine sediment plumes toward the center of the lake where they settle from suspension (hypopycnal flow). Although applicable as a general model, the sediment record shows that reality is more complex. Variations in meromixis and level of the chemocline, together with local and temporal differences in sediment yield and discharge, may permit density flows even when the lake is under a predominant hypopycnal regime. During periods of aridity when sodium carbonate evaporites were forming, exposed delta plains were subject to desiccation with local development of calcrete and zeolitic paleosols.

  4. Underflows in Lake Constance - Numerical Modeling, Instrumental Observations and Sediment Data

    Eder, Magdalena; Wessels, Martin; Dare, Julian


    A torrential rain event in the western Alps in August 2005 caused high flood flows in the rivers Alpine Rhine and Bregenzer Ache which are the main tributaries into Lake Constance. The discharge of the Alpine Rhine reached 2200 m³/s, which is little below a centennial flood event. Discharge of the Bregenzer Ache was estimated to 1350 m³/s which statistically occurs every 100 yr but with a 1000 yr frequency in selected smaller tributaries. The high concentration of suspended solids in the fluvial water increased its density and created an underflow with considerable influence on the lake's hydrodynamics and water quality. Consequences within the lake were directly registered by a mooring (equipped with thermistor chain, sediment trap, current meter, oxygen sensor). Spatial data of the path and form of suspended matter cloud within the lake were gathered using echo sounder and probe measurements (turbidity, temperature, salinity). An underflow with a temperature of 14°C flew with 1.4 km/h some 20 km into the lake. Several days after the event, the fluvial sediments were detected as increased turbidity at the drinking water outtakes around the lake. Sediment cores recovered from the lake bottom show the distribution pattern of the sediments while sidescan data give a picture from proximal sediment structures originating from this event. Further, we modelled this underflow using the three dimensional hydrodynamic and water quality model ELCOM-CAEDYM. The suspended solids module of the model accounts for the impact of the sediment load on water density. Settling is considered using Stokes Law, and resuspension can also be included. The simulation of the August 2005 flood event and comparison with measured data impressively showed the ability to reproduce the most important effects of the flood flow on the lake. Comparative simulations with and without consideration of the coriolis effect indicate an influence of the coriolis force on the flow path of the density

  5. The glacial/deglacial history of sedimentation in Bear Lake, Utah and Idaho

    Rosenbaum, J.G.; Heil, C.W.


    Bear Lake, in northeastern Utah and southern Idaho, lies in a large valley formed by an active half-graben. Bear River, the largest river in the Great Basin, enters Bear Lake Valley ???15 km north of the lake. Two 4-m-long cores provide a lake sediment record extending back ???26 cal k.y. The penetrated section can be divided into a lower unit composed of quartz-rich clastic sediments and an upper unit composed largely of endogenic carbonate. Data from modern fluvial sediments provide the basis for interpreting changes in provenance of detrital material in the lake cores. Sediments from small streams draining elevated topography on the east and west sides of the lake are characterized by abundant dolomite, high magnetic susceptibility (MS) related to eolian magnetite, and low values of hard isothermal remanent magnetization (HIRM, indicative of hematite content). In contrast, sediments from the headwaters of the Bear River in the Uinta Mountains lack carbonate and have high HIRM and low MS. Sediments from lower reaches of the Bear River contain calcite but little dolomite and have low values of MS and HIRM. These contrasts in catchment properties allow interpretation of the following sequence from variations in properties of the lake sediment: (1) ca. 26 cal ka-onset of glaciation; (2) ca. 26-20 cal ka-quasicyclical, millennial-scale variations in the concentrations of hematite-rich glacial fl our derived from the Uinta Mountains, and dolomite- and magnetite-rich material derived from the local Bear Lake catchment (reflecting variations in glacial extent); (3) ca. 20-19 cal ka-maximum content of glacial fl our; (4) ca. 19-17 cal ka-constant content of Bear River sediment but declining content of glacial fl our from the Uinta Mountains; (5) ca. 17-15.5 cal ka-decline in Bear River sediment and increase in content of sediment from the local catchment; and (6) ca. 15.5-14.5 cal ka-increase in content of endogenic calcite at the expense of detrital material. The onset

  6. Methane sources in arctic thermokarst lake sediments on the North Slope of Alaska.

    Matheus Carnevali, P B; Rohrssen, M; Williams, M R; Michaud, A B; Adams, H; Berisford, D; Love, G D; Priscu, J C; Rassuchine, O; Hand, K P; Murray, A E


    The permafrost on the North Slope of Alaska is densely populated by shallow lakes that result from thermokarst erosion. These lakes release methane (CH4 ) derived from a combination of ancient thermogenic pools and contemporary biogenic production. Despite the potential importance of CH4 as a greenhouse gas, the contribution of biogenic CH4 production in arctic thermokarst lakes in Alaska is not currently well understood. To further advance our knowledge of CH4 dynamics in these lakes, we focused our study on (i) the potential for microbial CH4 production in lake sediments, (ii) the role of sediment geochemistry in controlling biogenic CH4 production, and (iii) the temperature dependence of this process. Sediment cores were collected from one site in Siqlukaq Lake and two sites in Sukok Lake in late October to early November. Analyses of pore water geochemistry, sedimentary organic matter and lipid biomarkers, stable carbon isotopes, results from CH4 production experiments, and copy number of a methanogenic pathway-specific gene (mcrA) indicated the existence of different sources of CH4 in each of the lakes chosen for the study. Analysis of this integrated data set revealed that there is biological CH4 production in Siqlukaq at moderate levels, while the very low levels of CH4 detected in Sukok had a mixed origin, with little to no biological CH4 production. Furthermore, methanogenic archaea exhibited temperature-dependent use of in situ substrates for methanogenesis, and the amount of CH4 produced was directly related to the amount of labile organic matter in the sediments. This study constitutes an important first step in better understanding the actual contribution of biogenic CH4 from thermokarst lakes on the coastal plain of Alaska to the current CH4 budgets. © 2015 John Wiley & Sons Ltd.

  7. The Legacy of Arsenic Contamination from Giant Mine, Northern Canada: An Assessment of Impacts Based on Lake Water and Lake Sediment Core Analysis

    Blais, J. M.; Korosi, J.


    The Giant Mine, which operated between 1948 and 2004 and located near the City of Yellowknife (Northwest Territories, Canada), has left a legacy of arsenic, antimony, and mercury contamination extending to the present day. Over 20,000 tonnes of arsenic trioxide dust was released from roaster stack emissions during its first 10 years of operations, leading to a significant contamination of the surrounding landscape. Here we present a summary of impacts by the recent contamination from Giant Mine on the surrounding region. A survey we conducted of 25 lakes of the region in 2010 revealed that most lake water within a 15 km radius of the roaster stack had arsenic concentrations in water > 10 mg/L, the standard for drinking water, with concentrations declining exponentially with increasing distance from the roaster stack. Sediment cores from lakes were collected near the Giant Mine roaster stack and radiometrically dated by 137Cs and excess 210Pb. Arsenic concentrations in these sediments increased by 1700% during the 1950s and 60s, consistent with the history of arsenic releases from roaster emissions. Correspondingly, pelagic diatoms and cladocerans were extirpated from one lake during this period, based on microfossil analysis of lake sediment deposits. Sediment core analysis further showed that this lake ecosystem has not recovered, even ten years after closure of the mine. Likely causes for the lack of recent recovery are explored with the use of sediment toxicity bioassays, using a novel paleo-ecotoxicological approach of using toxicity assessments of radiometrically dated lake sediment horizons.

  8. Wind-driven nearshore sediment resuspension in a deep lake during winter

    Reardon, Kristin E.; Bombardelli, Fabián. A.; Moreno-Casas, Patricio A.; Rueda, Francisco J.; Schladow, S. Geoffrey


    Ongoing public concern over declining water quality at Lake Tahoe, California-Nevada (USA) led to an investigation of wind-driven nearshore sediment resuspension that combined field measurements and modeling. Field data included: wind speed and direction, vertical profiles of water temperature and currents, nearbed velocity, lakebed sediment characteristics, and suspended sediment concentration and particle size distribution. Bottom shear stress was computed from ADV-measured nearbed velocity data, adapting a turbulent kinetic energy method to lakes, and partitioned according to its contributions attributed to wind-waves, mean currents, and random motions. When the total shear stress exceeded the critical shear stress, the contribution to overall shear stress was about 80% from wind-waves and 10% each from mean currents and random motions. Therefore, wind-waves were the dominant mechanism resulting in sediment resuspension as corroborated by simultaneous increases in shear stress and total measured sediment concentration. The wind-wave model STWAVE was successfully modified to simulate wind-wave-induced sediment resuspension for viscous-dominated flow typical in lakes. Previous lake applications of STWAVE have been limited to special instances of fully turbulent flow. To address the validity of expressions for sediment resuspension in lakes, sediment entrainment rates were found to be well represented by a modified 1991 García and Parker formula. Last, in situ measurements of suspended sediment concentration and particle size distribution revealed that the predominance of fine particles (by particle count) that most negatively impact clarity was unchanged by wind-related sediment resuspension. Therefore, we cannot assume that wind-driven sediment resuspension contributes to Lake Tahoe's declining nearshore clarity.

  9. Proglacial lake sediments – a basis for uninterrupted chronicles of the Holocene glacier variations

    M. Y. Alexandrin


    Full Text Available The article covers the origin of paleolimnological method in glaciology, concerns the theoretical background of the approach, and focuses on the principal methods of analysis of the lake sediments and creating the sedimentary age-depth models. Lake sediments can provide a basis for creating uninterrupted reconstructions of the Holocene glacier variations with high resolution. The fundament of paleolimnological method is based on the differences between glacial and non-glacial components of the bottom sediments of proglacial lakes. The glacial signal in the lake sediments was originally distinguished by measuring the organic content of the sediment (normally with loss-on-ignition and the magnetic properties of the sediment. Subsequent methods of analysis could yield more precision and normally include geochemical composition (with the use of high-resolution scanning x-ray fluorescence analysis, use of biogenic indicators (such as pollen and diatoms contained in the sediment and more. Obtaining the most accurate age of the sediment is a crucial question in subsequent application of the sediment parameters for reconstruction of glacier variability. The article covers various methods of dating the lake sediment – radiocarbon, Cs- and Pb-isotope dating, varve counting. Techniques of creating age-depth models are taken into account. A state-of-the-art application of sedimentary properties in paleoglaciology yields a reconstruction of a former equilibrium line altitude – ELA. The article focuses on the basis of the ELA reconstruction approach. Successful examples of reconstructions of glacier variations based on the lake sediments can be found throughout the majority of the glaciated regions of the planet. The article states the most prominent of them and gives an update on the current progress in paleolimnological research in the Caucasus Mountains.

  10. Sub-fossils of cladocerans in the surface sediment of 135 lakes as proxies for community structure of zooplankton, fish abundance and lake temperature

    Jeppesen, E.; Jensen, J. P.; Lauridsen, T. L.


    zone. However, in most lakes the abundance of Ceriodaphnia was higher in the sediment than in the water, which may be attributed to the overall preference by this genus for the littoral habitat. Using contemporary data from 27 Danish lakes sampled fortnightly during summer for 10 years, we found...

  11. Impacts of flamingos on saline lake margin and shallow lacustrine sediments in the Kenya Rift Valley

    Scott, Jennifer J.; Renaut, Robin W.; Owen, R. Bernhart


    Studies of modern, Holocene, and Pleistocene sediments around saline to hypersaline, alkaline Lake Bogoria and Lake Magadi show that evidence of flamingo activity in marginal areas of these lakes is nearly ubiquitous. Flamingos produce discrete structures such as webbed footprints (~ 9 cm long, ~ 11 cm wide) and nest mounds (~ 30 cm wide, ~ 20 cm high), and they also extensively rework sediments in delta front, delta plain, and shoreline areas. Large (~ 0.5-2 cm in diameter), pinched, 'bubble pores' and ped-like mud clumps are formed by the trampling and churning of wet clay-rich sediments in these settings. Flamingo nest mounds, although superficially similar to some thrombolite mounds, are typically internally structureless, unless formed on pre-existing sediments that preserve internal structures. The flamingo mounds consist of a dense, packed oval-shaped core, a surrounding 'body' of packed sediment, and an external layer with a ped-like texture of clumped mud. The nests may contain open holes from roots or feather shafts incorporated into the nest, and (or) burrows produced once the nests are abandoned. In areas with high densities of flamingos, lake margin sediments may be preferentially compacted, particularly at breeding sites, and become resistant to subaerial erosion and the effects of transgressive ravinement on time scales ranging from seasons to tens of thousands of years. The relatively well-compacted nest mounds and associated sediments also contribute to the stability of delta distributary channels during regressive-transgressive cycles, and can lead to the minor channelization of unconfined flows where currents are diverted around nest mounds. Pleistocene exhumed surfaces of relatively well-indurated lake margin sediments at Lake Bogoria and Lake Magadi that are interpreted as combined regressive and transgressive surfaces (flooding surface/sequence boundary) preserve evidence of flamingo activities, and are overlain by younger, porous lacustrine

  12. Roseomonas lacus sp. nov., isolated from freshwater lake sediment.

    Jiang, Cheng-Ying; Dai, Xin; Wang, Bao-Jun; Zhou, Yu-Guang; Liu, Shuang-Jiang


    An aerobic, Gram-negative bacterial strain, TH-G33T, was isolated from freshwater sediment of Taihu Lake in China. The taxonomy of strain TH-G33T was studied by using phenotypic and phylogenetic methods. Cells of strain TH-G33T were coccoid rods or rods and formed colourless to pale-pink colonies on nutrient agar. Phylogenetic analysis based on nearly complete 16S rRNA gene sequences showed that strain TH-G33T was related to Roseomonas mucosa (94.4 %), Roseomonas gilardii subsp. gilardii (94.1 %), Roseomonas gilardii subsp. rosea (94.8 %) and Roseomonas cervicalis (93.9 %). Cells contained ubiquinone 10 (Q-10) as the major quinone and the G+C content was 71.9 mol%. Thus, strain TH-G33T represents a novel species of the genus Roseomonas, for which the name Roseomonas lacus sp. nov. is proposed. The type strain is TH-G33T (= CGMCC 1.3617T = JCM 13283T).

  13. Detection gas presence in lakes bottom sediments based on seismic investigations.

    Krylov, Pavel; Nurgaliev, Danis; Yasonov, Pavel


    Seismic investigations are used for various tasks, such as the study of the bottom sediments properties, finding sunken objects, reconstruction the reservoir history, etc. Detailed seismic investigation has been carried out in the southern part of Lake Bol'shoe Yarovoe (Altai Krai), Lake Sunukul (Chelyabinsk region), Lake Kisegach to map the bottom sediments and features associated with the presence of gas. The obtained results demonstrate that various types of gas can be recognized in lakes sediments, such as pockmarks, acoustic turbidity, gas flares, seeps. These features, on the one hand, prevent the reconstruction of sequence stratigraphic patterns and, on the other hand, contribute to understanding of the processes of gas formation and migration in the sediments, possible impacts of these processes on the formation of sediments enriched in the organic matter. Also, it helps to recognize these processes in the ancient sediments. The paper points out the importance of studying the formation of methane in lake sediments, because it plays an important role in the climate change. The work was carried out according to the Russia Government's Program of Competitive Growth of Kazan Federal University, supported by the grant provided to the Kazan State University for performing the state program in the field of scientific research, and partially supported by the Russian Foundation for Basic research (grant nos. 16-35-00452).

  14. Fast phosphorus loss by sediment resuspension in a re-established shallow lake on former agricultural fields

    Kragh, Theis; Sand-Jensen, Kaj; Petersen, Kathrine


    Lake restoration on fertilized agricultural fields can lead to extensive nutrient release from flooded soils which can maintain a poor ecological quality in the new lake. The period with high sediment release is poorly understood due to few detailed lake restorations studies. We conducted such a ...

  15. Inferring sources for mercury to inland lakes using sediment chronologies of polycyclic aromatic hydrocarbons.

    Parsons, Matthew J; Long, David T; Giesy, John P; Kannan, Kurunthachalam


    Sediment chronologies from inland lakes suggest the influence of local to sub-regional scale sources for mercury (Hg). However, apportionment of sources for Hg using sediment chronologies is difficult due to the mixing of sources and pathways. Mercury and polycyclic aromatic hydrocarbons (PAH) often share common sources and pathways into the environment. Thus, chronologies of PAHs in dated cores of sediments might be a useful tool to infer sources of Hg. Sediment cores from seven inland lakes of Michigan were collected for measurement of PAHs and Hg and dated by use of (210)Pb. PAH concentrations and ratios of kinetic and thermodynamic PAH compounds were used to infer sources of Hg. Ratios indicate the existence of modern combustion sources to each lake and historic combustion sources to lakes near cement kilns and an iron foundry. Coal combustion sources were identified for two lakes near urban centers. Whereas a petroleum combustion source was identified for a lake that has a coal fired power plant along its shoreline. These results have implications for the cycling of Hg on local to regional scales.

  16. Physical processes in Subglacial Lake Whillans, West Antarctica: Inferences from sediment cores

    Hodson, T. O.; Powell, R. D.; Brachfeld, S. A.; Tulaczyk, S.; Scherer, R. P.


    The hydrologic system beneath the Antarctic Ice Sheet is thought to influence both the dynamics and distribution of fast flowing ice streams, which discharge most of the ice lost by the ice sheet. Despite considerable interest in understanding this subglacial network and its affect on ice flow, in situ observations from the ice sheet bed are exceedingly rare. Here we describe the first sediment cores recovered from an active subglacial lake. The lake, known as Subglacial Lake Whillans, is part of a broader, dynamic hydrologic network beneath the Whillans Ice Stream in West Antarctica. Even though "floods" pass through the lake, the lake floor shows no evidence of erosion or deposition by flowing water. By inference, these floods must have insufficient energy to erode or transport significant volumes of sediment coarser than silt. Consequently, water flow beneath the region is probably incapable of incising continuous channels into the bed and instead follows preexisting subglacial topography and surface slope. Sediment on the lake floor consists of till deposited during intermittent grounding of the ice stream following flood events. The fabrics within the till are weaker than those thought to develop in thick deforming beds suggesting subglacial sediment fluxes across the ice plain are currently low and unlikely to have a large stabilizing effect on the ice stream's grounding zone.

  17. Rapid changes in Late Pleistocene precipitation and stream discharge determined from medium- and coarse-grained sediment in saline lakes

    Anderson, Roger Y.


    Sediment-trapping investigations in Pyramid Lake, Nevada show that medium- to coarse-grained clastic sediments suspended in streamflow after periods of low flow can be transported several kilometers in plumes of freshwater discharged over the surface of a saline lake. Analogous conditions are postulated to explain changes in the abundance of detrital quartz in lake clay near the center of Estancia Basin, New Mexico during the Late Pleistocene. Abrupt increases in the abundance of quartz grains mark the onset of lake freshening, and ostracode and trace-metal proxies for salinity indicate repeated, brief episodes of streamflow and lake freshening during the Last Glacial Maximum (LGM).

  18. Long Term Atmospheric and Erosional Pollution As Recorded in Lake Sediments from Yunnan, China

    Hillman, A. L.; Abbott, M. B.; Yu, J.; Bain, D.; Chiou-Peng, T.


    Human activities including agriculture, metallurgy (e.g. mining, processing, smelting), and deforestation have altered cycles of erosion and sedimentation in lake environments for thousands of years. In the Yunnan province of southwestern China, where written records are incomplete, it is unclear when, where, and how much disturbance occurred. Lake sediments offer a means to investigate a wide variety of human activities. Here, we present a lake sediment record from Erhai (25°43'N, 100°12'E) based on trace metal concentrations that reveals substantial atmospheric and erosional pollution to the lake environment over the last 4,000 years. Sediments indicate the initiation of copper-based metallurgy at 3,600 years BP, the existence of which has been debated amongst archaeologists. Beginning 2,000 years BP, sedimentation rates increase and concentrations of metals such as aluminum, titanium, lead, and zinc increase. This is likely linked to increased sediment flux to the lake associated with the initiation of terraced agriculture according to historical documents. The most prominent feature of the record is an abrupt and intense increase in lead, silver, cadmium, and zinc beginning at 700 years BP. The peak of this increase occurs at 600 years BP and is consistent with historical records that the Mongols established the first government operated silver mine in Yunnan. Notably, the concentrations of lead during this time are an order of magnitude greater than modern day levels of pollution.

  19. Characterization of the bacterial community in the sediment of a brackish lake with oyster aquaculture.

    Santander-De Leon, Sheila Mae S; Okunishi, Suguru; Kihira, Masaki; Nakano, Miyo; Nuñal, Sharon N; Hidaka, Masayasu; Yoshikawa, Takeshi; Maeda, Hiroto


    The physicochemical properties and bacterial community in sediments of Lake Shiraishi, a lake with brackish water, were characterized to elucidate the influence of oyster farming and seawater and freshwater inflow. Physicochemical analyses suggested the marine origin of the sediment at the mouth of the lake, while higher organic matter load and the resultant anaerobic, reductive condition of the sediments of the inner part were observed. The bacterial community in the sediments reflects these sediment environments: the bacterial community in the vicinities of oyster farms included sulfate-reducing bacteria (SRB) , although sulfur-oxidizing bacteria (SOB) were found at all the sampling sites. In addition, similarity of the band profiles obtained with 16S ribosomal RNA gene (16S rDNA) -denaturing gradient gel electrophoresis (DGGE) decreased in proportion to the distance from the mouth of the lake to the oyster farms in the inner part. This study was able to characterize the microbial community shift in brackish lake sediments with an oyster aquaculture system through the molecular fingerprinting technique, DGGE, in relation to their physicochemical characteristics.

  20. Modeling Hydrodynamics, Water Temperature, and Suspended Sediment in Detroit Lake, Oregon

    Sullivan, Annett B.; Rounds, Stewart A.; Sobieszczyk, Steven; Bragg, Heather M.


    Detroit Lake is a large reservoir on the North Santiam River in west-central Oregon. Water temperature and suspended sediment are issues of concern in the river downstream of the reservoir. A CE-QUAL-W2 model was constructed to simulate hydrodynamics, water temperature, total dissolved solids, and suspended sediment in Detroit Lake. The model was calibrated for calendar years 2002 and 2003, and for a period of storm runoff from December 1, 2005, to February 1, 2006. Input data included lake bathymetry, meteorology, reservoir outflows, and tributary inflows, water temperatures, total dissolved solids, and suspended sediment concentrations. Two suspended sediment size groups were modeled: one for suspended sand and silt with particle diameters larger than 2 micrometers, and another for suspended clay with particle diameters less than or equal to 2 micrometers. The model was calibrated using lake stage data, lake profile data, and data from a continuous water-quality monitor on the North Santiam River near Niagara, about 6 kilometers downstream of Detroit Dam. The calibrated model was used to estimate sediment deposition in the reservoir, examine the sources of suspended sediment exiting the reservoir, and examine the effect of the reservoir on downstream water temperatures.

  1. Assessment of metal concentrations in sediments from Lake Bafa (Western Anatolia): an index analysis approach.

    Yilgor, Sinem; Kucuksezgin, Filiz; Ozel, Erdeniz


    Metals, organic carbon contents were determined in surficial and core sediment samples from Lake Bafa, Western Anatolia in 2010. The ranges of Fe, Mn, Pb, Cu, Ni, Cr, Zn and Hg contents of sediments from the Bafa Lake were 9.4-35 g kg(-1), 250-780, 2.3-20, 5.8-55, 1.2-480, 63-278, 26.6-79.9 and 0.013-0.273 mg kg(-1), respectively. The mean metal concentrations in surficial sediments obtained in this study decreased in the following order; Fe > Mn > Ni > Cr > Zn > Cu > Pb > Hg for Bafa lake. Total organic carbon concentrations of the bottom sediments from the Bafa Lake varied between 0.35% and 3.58%. The mean concentrations of metal were lower than the background levels in earth crust except Cr and Ni in the core sediments. The metal levels were evaluated according to the New Geo-accumulation Index, enrichment and contamination factors. The results confirmed that the Bafa Lake is not facing serious environmental pollution risk due to metal contamination except Hg. The levels of Cr, Ni, Cu, Fe, Zn and Mn generally appear to be uniformly distributed with depth except Hg and Pb due to anthropogenic sources in the core sediments.

  2. Lake Cadagno

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco


    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur cyc...

  3. Geochemical and Geophysical Analysis of Holocene-aged Sediments from Southeastern Tulare Lake, CA

    Prosser, L.; Jackson, B.; Roza, J.


    Tulare Lake is located in the San Joaquin Valley of California west of the Sierra Nevada mountains (Preston, 1981). The Poso Canal trench locality is located in the southeastern portion of Tulare Lake in the Ton Tachi lake plane south of the Atwell Island sand spit. This area was chosen because these sediments lie beneath a road bed that predates agricultural tilling, preserving late-Holocene lake sediments. Sediments from trench TL13-7C were sampled for geophysical and geochemical analyses in order to create a higher resolution lake-level history during the late-Holocene than had been possible using only lithologic descriptions. The new record is comprised of grain size, clay percentage, carbon/nitrogen (C/N) ratios, total inorganic carbon (TIC), total organic carbon (TOC), and nitrogen (N) analyses taken at 2-cm intervals over 181-cm of section comprising four lithologic units. From oldest to youngest, Unit 1A consists of relatively equal and steady percentages of clay, silt, and sand, and relatively low C/N ratios, TIC, TOC, and N, suggesting an unproductive lake and relatively deep lake levels at this high elevation site. Fluctuating C/N ratios, a steady decrease in clay percentage, and a steady increase in sand percentage in Unit 1B suggests periods of flooding and fluctuating lake levels and eventually shallow evaporative lake conditions, as evidenced by a considerable and sudden increase in TIC (to 4.51%) in Unit 2. In addition to the drastic change in TIC, Unit 2 shows evidence of a large influx of terrestrial organic matter perhaps transported by floods by an increase in sand percentage and two pronounced spikes in C/N ratios to 38 and 65 (Meyers and Lallier-Verges, 1999). Unit 3 shows low but steady levels of clay and sand percentages, and higher but steady levels of silt. Levels of TIC, TOC, C/N, and N are all steady, with relatively higher levels of TOC and N, which are indicators of high lake level and productivity (Cohen, 2003). Unit 4 is very similar

  4. Sediment dynamics and heavy metal pollution history of the Cruhlig Lake (Danube Delta, Romania).

    Begy, Róbert-Csaba; Preoteasa, Luminita; Timar-Gabor, Alida; Mihăiescu, Radu; Tănăselia, Claudiu; Kelemen, Szabolcs; Simon, Hedvig


    This is the first study reporting recent sedimentation rates data (e.g. the past 120-150 years) for the Cruhlig Lake situated in the Danube Delta. The aim of this study is to analyse the recent sedimentation rates using the (210)Pb dating method and identifying the heavy metal pollutants and their variability in time. Five sediment cores were taken with a gravity corer and - after drying the sliced samples-physical parameters, organic material and inorganic carbon content were determined. The total (210)Pb content was measured via (210)Po by alpha spectrometry, while supported (210)Pb was measured by (226)Ra (trough short life (222)Rn daughters) with HPGe detectors. Heavy metals were determined by ICP-MS; from the 64 measured elements, only exceeding values of Al, As, Cd, Co, Cs, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Ni, Pb and Zn are discussed. After applying the CRS model, ages and sedimentation rates were calculated. The average sedimentation rate of the Cruhlig Lake is 0.21 ± 0.02 g/cm(2)y, Minimum values (0.05 ± 0.003 g/cm(2)y) are registered along the eastern shoreline of the lake before 1913, while maximum values are recorded due to the flooding in 2006 in the western side (1.34 ± 0.12 g/cm(2)y). Recent sedimentation rates divide the lake into three areas: the secluded eastern near shore part (0.63 ± 0.07 g/cm(2)y), the centre of the lake (0.92 ± 0.05 g/cm(2)y) and the dynamic western area, where most sediment transport takes place (1.13 ± 0.01 g/cm(2)y). The sedimentation pattern proves this lake to be very sensitive to fluvial discharge fluctuations. The building of the Iron Gate dams (1972 and 1985) had a negative impact on the sedimentation decreasing it with 58.74%, while after 1989 these values grew 2.25 times. The lake received a quantity of sediment rich in heavy metals in 1992 ± 3 y, which settled mostly on the eastern part. Values for Cd, Co, Cr, Hg, Pb and Zn are up to five times higher in 1980 ± 5 y in the eastern part of the lake, while Cd, Co



    The governing equation for sediment pollutions was derived based on the turbulent diffusion of pollutants in shallow lakes. Coupled with shallow water equations, a depth-averaged 2-D flow and water quality model was developed. By means of the conservation law, a proposed differential equation for the change of sediment pollutants was linked to the 2-D equations. Under the framework of the finite volume method, the Osher approximate Riemann solver was employed to solve the equations. An analytical resolution was used to examine the model capabilities. Simulated results matched the exact solutions especially well. As an example, the simulation of CODMn in the Wuli Lake, a part of the Taihu lake, was conducted, which led to reasonable results. This study provides a new approach and a practical tool for the simulation of flow and water quality in shallow lakes.

  6. Mercury pollution in the lake sediments and catchment soils of anthropogenically-disturbed sites across England.

    Yang, Handong; Turner, Simon; Rose, Neil L


    Sediment cores and soil samples were taken from nine lakes and their catchments across England with varying degrees of direct human disturbance. Mercury (Hg) analysis demonstrated a range of impacts, many from local sources, resulting from differing historical and contemporary site usage and management. Lakes located in industrially important areas showed clear evidence for early Hg pollution with concentrations in sediments reaching 400-1600 ng g(-1) prior to the mid-19th century. Control of inputs resulting from local management practices and a greater than 90% reduction in UK Hg emissions since 1970 were reflected by reduced Hg pollution in some lakes. However, having been a sink for Hg deposition for centuries, polluted catchment soils are now the major Hg source for most lakes and consequently recovery from reduced Hg deposition is being delayed.

  7. A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation

    Brydsten, Lars [Umeaa Univ. (Sweden). Dept. of Biology and Environmental Science


    A mathematical model for simulation of lake basin filling processes in areas with positive shore displacement was constructed. The model was calibrated using sediment and catchments data from eight existing lake basins situated in the northern coastal area of the province of Uppland, Sweden. The lake basin filling processes were separated into three phases: basin filling with wave-washed material (silt, silty sand or sand), filling with fine-grained material during the shallow gulf and lake stages, respectively, and filling with vegetation during the lake stage. The basin filling rates for wave-washed material were generally low but varied considerably both between and within lakes. The mean basin filling rate of wave-washed material was 4.1%. The volume of inorganic sediments produced, and basin filling rates during the shallow gulf and lake phases were determined for all the eight lakes. The relationship between basin filling rate and parameters describing the catchments, the former postglacial basins and the lakes, respectively, was determined using multiple regression analysis. The basin filling rate with inorganic sediments was best described by parameters related to former postglacial basin morphometry and current lake morphometry, e.g. basin volume, lake volume, and lake area. The goodness of fit turned out to be 0.99 for a simple regression with basin volume as the sole independent variable. The basin filling with vegetation (Phragmites australis followed by Sphagnum spp.) was treated as a 2-dimensional process. A dataset with 84 bogs was selected from a digital soil map. The ages of the bogs were calculated using a digital elevation map and an equation for shore displacement. The choke-up rate was then calculated by dividing the area of the bogs with their age. A strong exponential relationship exists between areas of the bogs and choke-up rat, and this relationship was then used in the model. The resulting model starts by filling the former coastal basin


    Petre GÂŞTESCU


    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  9. Sources and sinks of microplastics in Canadian Lake Ontario nearshore, tributary and beach sediments.

    Ballent, Anika; Corcoran, Patricia L; Madden, Odile; Helm, Paul A; Longstaffe, Fred J


    Microplastics contamination of Lake Ontario sediments is investigated with the aim of identifying distribution patterns and hotspots in nearshore, tributary and beach depositional environments. Microplastics are concentrated in nearshore sediments in the vicinity of urban and industrial regions. In Humber Bay and Toronto Harbour microplastic concentrations were consistently >500 particles per kg dry sediment. Maximum concentrations of ~28,000 particles per kg dry sediment were determined in Etobicoke Creek. The microplastic particles were primarily fibres and fragments microplastics in terms of how and where to implement preventative measures to reduce the contaminant influx. Although the impacts of microplastics contamination on ecosystem health and functioning is uncertain, understanding, monitoring and preventing further microplastics contamination in Lake Ontario and the other Great Lakes is crucial.

  10. The possibility of using macrophytes in lake Palić sediment remediation

    Petričević J.


    Full Text Available Lake Palić is a typical, shallow Pannonian plain lake, with thick sediment layers and high content of phosphorus and nitrogen. The thick layers are the result of accelerated eutrophication, and cause biodiversity loss and disruption of the ecosystem. Numerous methods can be used to overcome the problem of accelerated eutrophication, (sediment removal, phosphorus inactivation etc.. However, these methods have many deficiencies. Lately, using macrophytes as a way to resolve this problem is becoming more and more popular. The aim of this work was to examine the germination possibilities of white mustard (Sinapis alba L., alfalfa (Medicago sativa L., oats (Avena sativa L. and lettuce (Lactuca sativa L. on Lake Palić’s sediment, as a prescreening test for their suitability for further phytoremediation. The results show that plant species can germinate and grow in early stages in such substrates, so they can be recommended for sediment phytoremediation. [Projekat Ministarstva nauke Republike Srbije, br. TR 31080

  11. Application of MODIS data in monitoring suspended sediment of Taihu Lake, China

    JIANG Xingwei; TANG Junwu; ZHANG Minwei; MA Ronghua; DING Jing


    Application of MODIS in ocean color is mainly based on bands 8-16 with the spatial resolution of 1 000 m. This spatial resolution, however, can not meet the application demand of inland waters where the areas are relatively small. With the assumption of the black water at shortwave infrared (SWIR) wavelengths (>1 000 nm), we first propose an atmospheric correction method for bands 1 and 2 with their spatial resolution of 250 m, and we then establish a quantitative retrieval model for suspended sediment concentration retrieval using the in-situ data collected in Taihu Lake. We also use MODIS data to retrieve the suspended sediment concentration of Taihu Lake with the retrieval model. The comparison between the retrieved and measured suspended sediment concentrations confirms that our algorithm can provide reliable data for monitoring the suspended sediment in Taihu Lake.

  12. Assessment of the mutagenic potential of Skadar Lake sediments using the salmonella microsomal assay

    Perović Svetlana


    Full Text Available Organic extracts of sediments from Skadar Lake (National park and protected RAMSAR site were investigated for their mutagenic potential using Salmonella typhimurium TA98 and TA100 strains in the presence and absence of metabolic activation. Five different concentrations of sediment extracts from five different sampling sites were assayed, and mutagenic results were obtained for both strains. These studies present a part of the EULIMNOS project and included a battery of bioassay testing and in situ investigations of microbial community structures of Skadar Lake sediments. The obtained results show mutagenic risk potential in five collected samples in the absence and presence of metabolic activation. Additional studies are required in order to identify and quantify the chemical compounds responsible for the mutagenic activity present in Skadar Lake sediments.

  13. Rock Magnetic Detection of Two Coercivity Components of Magnetosomes in Lake Ely Sediments

    Kodama, K. P.; Chen, A.; Egli, R.; Vavrek, J.


    The modeling of IRM acquisition curves has become an important tool used by environmental magnetists to characterize a sample's magnetic mineralogy. We have applied IRM modeling to lake sediments from Lake Ely, a small, post-glacial lake located in northeastern Pennsylvania. The lake is unique in having a strong sedimentary magnetization dominated by the magnetosomes produced by magnetotactic bacteria. Measurements of Fe, S, and O2 at different depths in the lake's water column, as well as the magnetization of material filtered from the water, indicate that magnetotactic bacteria live in the water column at the oxic-anoxic interface. Magnetic measurements and TEM observations of lake sediments and material caught in a sediment trap indicate that magnetosomes are the major constituent of the magnetic minerals in the lake sediments. IRM modeling shows two separate coercivity components at about 30 mT and 60 mT that are consistent with Egli's (2004) observations of BS (biogenic soft) and BH (biogenic hard) coercivity components for magnetosomes in lake sediments. However, the peaks are poorly determined because only 6-7 data points constrain the 0-100 mT part of the IRM coercivity spectrum. We used pARMs (97 μT DC field) applied in 5 mT alternating field steps between 0 and 100 mT to better resolve the BH and BS coercivity peaks. pARM spectra collected from lake sediment samples reveal one strong coercivity peak at approximately 30 mT in the 0-100 mT range. A second higher coercivity peak at about 80 mT is weakly evident in some samples. Alternating field demagnetization in 104 steps of an ARM applied to one sample also suggests the presence of two coercivity peaks but at 20 and 40 mT. First order reversal curves (FORCs) measured at the Institute for Rock Magnetism show that the magnetic grains behave as non-interacting single domain grains, implying that the magnetosome chains are relatively far apart and probably still intact. The FORC diagrams also show a large

  14. A statistical approach for determining the envi-ronment impact of surface sediments from the Dongting Lake area, central China

    YAO Zhigang; BAO Zhengyu; ZHOU Lifa; GAO Pu


    The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sedi-ments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake's coastline and sev-eral tributaries on the profiles of nutrients and heavy metals in the lake's surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely ad-sorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.

  15. Halogens in the Dry Valleys Lakes, Antarctica: dynamic cycling between water, sediment, and cryogenic evaporites

    Snyder, G. T.; Dowling, C. B.; Harbert, A.; Lu, H.; Lyons, W. B.; Welch, K. A.


    Many of the McMurdo Dry Valleys lakes of Antarctica exhibit saline to hypersaline bottom waters whose chemistry is distinct from that of sea water. The source and relative abundance of dissolved Cl, Br, and I in these unusual waters has been modified by several potential processes including: seawater incursions, water- rock interactions, microbial scavenging, glacial melting and precipitation, and atmospheric deposition. Since all of these processes are affected by both long-term and short-term climate change, lake waters and the salts that are deposited around them provide sensitive indicators of lake dessication and refilling in the past. We present elemental analyses, not only of the lake water, but also of bottom sediments and cryogenic evaporites recovered from the Dry Valleys. XRD analyses indicate that gypsum and antarcticite are precipitated around saline lakes presently situated more than 40 km from the ocean (Vanda, Don Juan, Joyce), while mirabilite is found near small pools in the Garwood Valley, only a few km from the ocean. Lake water enrichments in Ca and Cl, relative to Na suggest that either dissolution of gypsum and antarcticite has occurred in Don Juan Pond and Lake Vanda, or that these two small bodies of water previously lost sodium to mirabilite formation. Lakes Fryxell and Joyce, as well as waters in Garwood Valley show near-sea water ratios. Dissolved iodine, and to a lesser extent bromine, are commonly associated with diagenesis of marine organic matter in regions of high productivity, so it is surprising that the Dry Valleys lake waters are enriched in these two elements. These enrichments are also apparent in pore fluids of shallow sediments on the lake bottoms. In addition, the sediments themselves are highly enriched in iodine in the upper 5 cm (up to 77 ppm). This is likely due to remobilization of dissolved iodide, which is mobile in reduced form, but becomes fixed as adsorbed or organic iodine upon diffusing into shallow oxic

  16. Analyzing the causes for the persistence of chironomids in flood plain lake sediments

    Haas, de E.M.; Haaren, van R.; Koelmans, A.A.; Kraak, M.H.S.; Admiraal, W.


    The aim of the present study was to analyse the causes for the absence and persistence of chironomids in sediments with a complex pollution history. Observations on the benthic community composition in floodplain lake sediments of the River Rhine, differing in contaminant level and food quality, wer

  17. Distribution of metals in fauna, flora and sediments of wet detention ponds and natural shallow lakes

    Stephansen, D.A.; Nielsen, A.H.; Hvitved-Jacobsen, T.;


    Fauna, flora, and sediment were collected from 9 wet detention ponds receiving stormwater runoff and 11 small natural shallow lakes. The fauna and flora samples were sorted into species or groups of species and, together with sediments, analyzed for aluminum, copper, iron, zinc, arsenic, cadmium,...

  18. Distribution of metals in fauna, flora and sediments of wet detention ponds and natural shallow lakes

    Stephansen, D.A.; Nielsen, A.H.; Hvitved-Jacobsen, T.


    Fauna, flora, and sediment were collected from 9 wet detention ponds receiving stormwater runoff and 11 small natural shallow lakes. The fauna and flora samples were sorted into species or groups of species and, together with sediments, analyzed for aluminum, copper, iron, zinc, arsenic, cadmium,...

  19. Reaction rates, depositional history and sources of indium in sediments from Appalachian and Canadian Shield lakes

    Tessier, André; Gobeil, Charles; Laforte, Lucie


    Sediment cores were collected at the deepest site of twelve headwater lakes from the Province of Québec, Canada that receive contaminants only from atmospheric deposition, either directly to the lake surface or indirectly from the watershed. Several of the lakes are located within relatively short distance (In2S3(s) do not precipitate in the sediments and that adsorption of In onto sedimentary FeS(s) does not occur. However, similarities in the In and Fe porewater profiles, and the presence of In in the authigenic Fe-rich solids, reveal that part of the In becomes associated with authigenic Fe oxyhydroxides in the perennially oxic lake and is coupled to the Fe redox cycling. Comparison of the In/Corg and In/Fe molar ratios in the authigenic Fe-rich material and in surface sediments (0-0.5 cm) of this lake suggests that most non-lithogenic In was bound to humic substances. From the magnitude of the net In reaction rates, we infer that the post-depositional redistribution of this element is quantitatively not important and that the In sedimentary record represents accurately In deposition at the sampling sites. Reconstructed chronologies of the anthropogenic In deposition and comparison of In inventories among lakes point to non-ferrous metal smelters as a past significant source of atmospheric In contamination and to a significant reduction of industrial In emissions into the North American atmosphere in recent decades.

  20. Spatial distribution and pollution assessment of mercury in sediments of Lake Taihu, China

    Chunxiao Chen; Binghui Zheng; Xia Jiang; Zheng Zhao; Yuzhu Zhan; Fengjiao Yi; Jiaying Ren


    Spatial distribution patterns of total mercury (THg) in 36 surficial sediment samples representing five regions of Lake Taihu were assessed using the ArcGis geostatistical analyst module.The pollution levels of THg were also evaluated from the same five lake regions.Concentrations of THg were in a ranged of 23-168 ng/g (mean 55 ng/g) in surfical sediments,which was significantly higher than those established baseline levels of the lake.Results of THg indicated that the northern region exhibited notably higher values,the bay regions showed elevated values relative to open areas,and the lakeside regions were higher than those observed in the central area.Lake Taihu suffered moderate to high Hg pollution,and expressed clear Hg enrichment status according to monomial pollution index Igeo and human activity factors.The concentrations of THg in the surticial sediments of Lake Taihu showed moderate-strong variation (coefficient of variation 52%).Geostatistical analysis indicated a weak spatial self-correlation,suggesting the contamination of Hg in Lake Taihu is primarily the result of anthropogenic activities.

  1. Mercury in sediment, water, and fish in a managed tropical wetland-lake ecosystem.

    Malczyk, Evan A; Branfireun, Brian A


    Mercury pollution has not been well documented in the inland lakes or fishes of Mexico, despite the importance of freshwater fish as a source of protein in local diets. Total mercury and methylmercury in waters, sediments, and the commercial fish catch were investigated in Lake Zapotlán, Mexico. Concentrations of total and methylmercury were very high in runoff and wastewater inputs, but very low in sediments and surface waters of the open water area of the lake. Concentrations of total mercury in tilapia and carp were very low, consistent with the low concentrations in lake water and sediments. Particle settling, sorption, the biogeochemical environment, and/or bloom dilution are all plausible explanations for the significant reductions in both total mercury and methylmercury. Despite very high loading of mercury, this shallow tropical lake was not a mercury-impaired ecosystem, and these findings may translate across other shallow, alkaline tropical lakes. Importantly, the ecosystem services that seemed to be provided by peripheral wetlands in reducing mercury inputs highlight the potential for wetland conservation or restoration in Mexico.

  2. Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska

    Schiff, C J; Kaufman, D S; Wallace, K L; Werner, A; Ku, T L; Brown, T A


    A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS {sup 14}C ages, along with the {sup 137}Cs and {sup 210}Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of sediment, and to determine the age of each tephra deposit. The age model is based on a cubic smooth spline function that was passed through the adjusted tephra-free depth of each dated layer. The estimated age uncertainty of the 67 tephras averages {+-} 105 yr (1{sigma}). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7 per 500 yr over the last 8500 yr. Other periods of increased tephra fall occurred 2500-3500, 4500-5000, and 7000-7500 cal yr. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall separated by shorter periods (500-1000 yr) of apparent quiescence. The Bear Lake sediment core affords the most comprehensive tephrochronology from the base of the Redoubt Volcano to date, with an average tephra-fall frequency of once every 130 yr.

  3. Salinity Affects the Composition of the Aerobic Methanotroph Community in Alkaline Lake Sediments from the Tibetan Plateau.

    Deng, Yongcui; Liu, Yongqin; Dumont, Marc; Conrad, Ralf


    Lakes are widely distributed on the Tibetan Plateau, which plays an important role in natural methane emission. Aerobic methanotrophs in lake sediments reduce the amount of methane released into the atmosphere. However, no study to date has analyzed the methanotroph community composition and their driving factors in sediments of these high-altitude lakes (>4000 m). To provide new insights on this aspect, the abundance and composition in the sediments of six high-altitude alkaline lakes (including both freshwater and saline lakes) on the Tibetan Plateau were studied. The quantitative PCR, terminal restriction fragment length polymorphism, and 454-pyrosequencing methods were used to target the pmoA genes. The pmoA gene copies ranged 10(4)-10(6) per gram fresh sediment. Type I methanotrophs predominated in Tibetan lake sediments, with Methylobacter and uncultivated type Ib methanotrophs being dominant in freshwater lakes and Methylomicrobium in saline lakes. Combining the pmoA-pyrosequencing data from Tibetan lakes with other published pmoA-sequencing data from lake sediments of other regions, a significant salinity and alkalinity effect (P = 0.001) was detected, especially salinity, which explained ∼25% of methanotroph community variability. The main effect was Methylomicrobium being dominant (up to 100%) in saline lakes only. In freshwater lakes, however, methanotroph composition was relatively diverse, including Methylobacter, Methylocystis, and uncultured type Ib clusters. This study provides the first methanotroph data for high-altitude lake sediments (>4000 m) and shows that salinity is a driving factor for the community composition of aerobic methanotrophs.

  4. Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes

    De Lucas Pardo, M.A.; Sarpe, D.; Winterwerp, J.C.


    Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We s

  5. [Composition and Environmental Effects of LFOM and HFOM in "Incense-Ash" Sediments of West Lake, Hangzhou, China].

    Li, Jing; Zhu, Guang-wei; Zhu, Meng-yuan; Gong, Zhi-jun; Xu, Hai; Yang, Gui-jun


    To understand the organic matter pollution characteristic and its relationship with nitrogen, phosphorus and other nutrients in sediments of high organic matter type of urban shallow lakes, the organic matter content, light fraction organic matter (LFOM), heavy fraction organic matter (HFOM), and nitrogen and phosphorus contents were investigated in eight different regions of West Lake, Hangzhou. The results showed that, the organic matter content of the west lake sediment was 28-251 g x kg(-1), belonging to typical high organic matter sediment. The difference of organic matter content in different lake sediments was very big. The sediments located at the input site of water diversion engineering had significantly lower organic content than the rest regions. The LFOM content of West Lake sediment ranged 0.57-9.17 g x kg(-1), which averagely occupied 2.83% of the total organic matter, and the HFOM content ranged 5.35-347.41 g x kg(-1), which occupied more than 90% of the total organic matter. Compared to other shallow lakes located in China, sediments of West Lake had significantly high percentage of HFOM/LFOM ratio. But the HFOM content was obviously on the high side, reflecting the west lake as an urban lake with a long history, as well as high organic matter pollution load and sediment humification degree. Both the content and the ratio of LFOM/HFOM in sediment were related to nitrogen and phosphorus contents in sediment. This suggested that the composition of organic matter in West Lake sediments had potential control ability for the internal loading of N and P of the lake.

  6. Expressions of climate perturbations in western Ugandan crater lake sediment records during the last 1000 yr

    K. Mills


    Full Text Available Equatorial East Africa has a complex, regional patchwork of climate regimes, with multiple interacting drivers. Recent studies have focussed on large lakes and reveal signals that are smoothed in both space and time, and, whilst useful at a continental scale, are of less relevance when understanding short-term, abrupt or immediate impacts of climate and environmental changes. Smaller-scale studies have highlighted spatial complexity and regional heterogeneity of tropical palaeoenvironments in terms of responses to climatic forcing (e.g. the Little Ice Age [LIA] and questions remain over the spatial extent and synchroneity of climatic changes seen in East African records. Sediment cores from paired crater lakes in western Uganda were examined to assess ecosystem response to long-term climate and environmental change as well as testing responses to multiple drivers using redundancy analysis. These archives provide annual to sub-decadal records of environmental change. The records from the two lakes demonstrate an individualistic response to external (e.g. climatic drivers, however, some of the broader patterns observed across East Africa suggest that the lakes are indeed sensitive to climatic perturbations such as a dry Mediaeval Climate Anomaly (MCA; 1000–1200 AD and a relatively drier climate during the main phase of the LIA (1500–1800 AD; though lake levels in western Uganda do fluctuate. The relationship of Ugandan lakes to regional climate drivers breaks down c. 1800 AD, when major changes in the ecosystems appear to be a response to sediment and nutrient influxes as a result of increasing cultural impacts within the lake catchments. The data highlight the complexity of individual lake response to climate forcing, indicating shifting drivers through time. This research also highlights the importance of using multi-lake studies within a landscape to allow for rigorous testing of climate reconstructions, forcing and ecosystem response.

  7. Chemical indicators of anthropogenic impacts in sediments of the pristine karst lakes.

    Mikac, I; Fiket, Z; Terzić, S; Barešić, J; Mikac, N; Ahel, M


    The anthropogenic impact on the pristine karst lakes was investigated using combination of specific parameters, including multielemental analysis of major inorganic constituents (Al, K, Fe) and trace metals (Li, Ag, Cd, Sn, Pb, Bi, Cr, Co, Ni, Cu, Zn and Sb), polycyclic aromatic hydrocarbons (PAHs) and anionic surfactants of linear alkylbenzene sulfonate (LAS) type. The study was performed in the Plitvice Lakes National Park, situated in a sparsely populated area of the northwestern Dinarides, central Croatia. Dated cores of recent sediments from the two biggest lakes, Lake Prosce and Lake Kozjak, were analysed for the selected contaminants using highly specific methods, involving inductively coupled plasma mass spectrometry (ICP/MS), gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentration of inorganic constituents reflected primarily the geological background of the area as well as geomorphological and geochemical characteristics of the Plitvice Lakes. Due to the higher terrigenous input, the concentration of all elements was significantly higher in the Lake Prosce. The concentration of toxic metals was relatively low in both lakes, except for Cd (>1 mg kg(-1)) and Pb (up to 40 mg kg(-1)). The vertical profiles of these metals suggested that elevated concentrations of Cd were of natural origin, derived from the erosion of the Jurassic dolomite bedrock, while Pb was predominately of recent anthropogenic origin. A similar distribution pattern, suggesting the same prevailing mechanism of input, was observed for pyrolytic PAHs. The characteristic diagnostic PAH ratios revealed that higher PAHs prevailingly originated from the combustion of biomass and fossil fuels. LAS, which represent highly specific indicators of untreated wastewaters, were found in rather high concentrations in the recent sediment layers (up to 4.7 mg kg(-1)), suggesting that contaminated household and hotel wastewaters reach the

  8. Cliff-nesting seabirds influence production and sediment chemistry of lakes situated above their colony.

    Hargan, K E; Michelutti, N; Coleman, K; Grooms, C; Blais, J M; Kimpe, L E; Gilchrist, G; Mallory, M; Smol, J P


    Seabirds that congregate in large numbers during the breeding season concentrate marine-derived nutrients to their terrestrial nesting sites, and these nutrients disperse and enhance production in nearby terrestrial, freshwater and marine ecosystems. In the Canadian Arctic, large seabird colonies (>100,000 breeding pairs) nest on cliff faces that drain directly in the ocean, ultimately returning the nutrients back to the marine environment from which they were derived. However, strong winds blowing up cliff faces could transport nutrients up in elevation and onto surrounding terrestrial and aquatic environments. Here, we assess the degree to which seabird nutrients and metals have been delivered to coastal lakes near Hudson Strait (Nunavut, Canada) over the past century. Three lakes located at a higher elevation and increasing distance from a thick-billed murre (Uria lomvia) colony (~400,000 breeding pairs) were sampled for surface water chemistry. In addition, algal assemblages, nitrogen isotopes, and metal/metalloids were analyzed in four dated sediment cores. Elevated nutrients and major ions, as well as an enriched δ(15)N signature in the sediment cores, were measured in the lake lakes >1km from the seabird colony. In contrast, similar oligotrophic and benthic diatom assemblages were identified in all three lakes, suggesting that diatoms were not influenced by enhanced nutrient inputs in this Arctic environment. Chemical tracers (e.g., total mercury) and algal assemblages in the lake near the colony suggest climate warming since ~1950 was the most likely driver of limnological changes, but this effect was muted in the more distant lakes. These pronounced changes in the seabird-impacted lake suggest that, with warming air temperatures and diminished lake ice cover, longer growing seasons may allow for aquatic organisms to more fully exploit the seabird nutrient subsidies.

  9. Wind influence on the course of sedimentation processes of the laminated lacustrine sediments of Lake Czechowskie

    Wiśniewska, Daria; Kramkowski, Mateusz; Tyszkowski, Sebastian


    The studies of the laminated lacustrine sediments play a very important role in the analysis of climate change. They provide valuable information related to the response of the ecosystem to changes in the environment. The condition for the development of the annual lamination is calm sedimentation, which can be compromised by the movement of water caused by waving. The depth to which this movement affects depends on the shape of the lake basin as well as the velocity and direction of the wind. During the study of sedimentary processes of laminated deposits in Lake Czechowskie (Tuchola Forest, North Poland, 53°52'N, 18°14' E, 108 m asl), the following question arose: How strong was the influence of the wind on the processes of lacustrine sedimentation? The key in getting the answers was the use of GIS techniques. Lake Czechowskie has an area of 76.6 hectares; it has two deeps separated by a threshold: a deeper one of 33 m (maximum depth of the basin) in the central-eastern part, and a shallower of 13 m in the western part. The speed of movement of water that is able to move sediment from the bottom of the lake, called the orbital wave velocity, is the basis for the designation of areas where re-suspension takes place. To calculate the wave parameters, the process of mixing, as well as the designation of re-suspension zones, the tool-script Wave Model (Rohweder et al. 2008) in the program ArsGIS 10.1 was used. The input data were wind direction and velocity from the meteorological station of Wirty about 15 km away, bathymetric data from acoustic profiling, and the Maximum Orbital Wave Velocity. The elements taken into account include maximum wind velocity of the multi-year 1996-2013, with particular emphasis on hurricanes Ksawery (December 2013) and Yoda (November 2011), during which wind velocity exceeded 120 km/h. In addition, maximum wind velocity ever recorded in the Polish Lowlands was considered. On the basis of the modelling, the authors delimited the areas

  10. Expressions of climate perturbations in western Ugandan crater lake sediment records during the last 1000 years

    Mills, K.; Ryves, D. B.; Anderson, N. J.; Bryant, C. L.; Tyler, J. J.


    Equatorial East Africa has a complex regional patchwork of climate regimes, sensitive to climate fluctuations over a variety of temporal and spatial scales during the late Holocene. Understanding how these changes are recorded in and interpreted from biological and geochemical proxies in lake sedimentary records remains a key challenge to answering fundamental questions regarding the nature, spatial extent and synchroneity of climatic changes seen in East African palaeo-records. Using a paired lake approach, where neighbouring lakes share the same geology, climate and landscape, it might be expected that the systems will respond similarly to external climate forcing. Sediment cores from two crater lakes in western Uganda spanning the last ~1000 years were examined to assess diatom community responses to late Holocene climate and environmental changes, and to test responses to multiple drivers using redundancy analysis (RDA). These archives provide annual to sub-decadal records of environmental change. Lakes Nyamogusingiri and Kyasanduka appear to operate as independent systems in their recording of a similar hydrological response signal via distinct diatom records. However, whilst their fossil diatom records demonstrate an individualistic, indirect response to external (e.g. climatic) drivers, the inferred lake levels show similar overall trends and reflect the broader patterns observed in Uganda and across East Africa. The lakes appear to be sensitive to large-scale climatic perturbations, with evidence of a dry Medieval Climate Anomaly (MCA; ca. AD 1000-1200). The diatom record from Lake Nyamogusingiri suggests a drying climate during the main phase of the Little Ice Age (LIA) (ca. AD 1600-1800), whereas the diatom response from the shallower Lake Kyasanduka is more complex (with groundwater likely playing a key role), and may be driven more by changes in silica and other nutrients, rather than by lake level. The sensitivity of these two Ugandan lakes to regional

  11. Linkage between land use patterns and sediment phosphorus sorption behaviors along shoreline of a Chinese large shallow lake (Lake Chaohu

    Zhou C.


    Full Text Available To test the relationship between phosphorus buffering capacity in sediments of littoral zone and land use, seasonal samples were taken from the soils representing different patterns of land use, together with the littoral zone sediments, along shoreline in Lake Chaohu. There existed significantly positive relationships between equilibrium phosphorus concentration (EPC0 and degree of phosphorus saturation (DPS defined as ratios of Olsen-P, algae available phosphorus (AAP and inorganic phosphorus (IP to maximum sorption capacity (Qmax. So, some easily accessible P parameters especially DPS were indicative of EPC0 in the sediments. Furthermore, the contents of IP, total phosphorus (TP and organic matter (OM in the sediments were significantly related to those in the soils. Therefore, the soils could provide the littoral zone with IP either directly or indirectly through TP input; it also provided the Olsen-P through the OM input, as evidenced by the relationship between Olsen-P and OM. It meant that the enhanced OM would enlarge the DPS. On the other hand, the increase in OM paralleled with the increases in Qmax, which lower the DPS simultaneously. Thus, the OM modified sediment phosphorus sorption behaviors in complicated manners. Finally, the soil covered by Fleabane was coupled with the sediment whose EPC0 values were lower and further decreased with strong diffusion from the soils after heavy rains. Hence, shoreline soil may input TP including IP and OM into the lake and alter the DPS together with EPC0 thereby regulating the sediment functions to act as sink or source of phosphorus.

  12. Reconstructing geomorphic patterns and forcing factors from Alpine Lake Sediment

    Arnaud, Fabien; Poulenard, Jérôme; Giguet-Covex, Charline; Wilhelm, Bruno; Révillon, Sidonie; Jenny, Jean-Philippe; Revel, Marie; Enters, Dirk; Bajard, Manon; Fouinat, Laurent; Doyen, Elise; Simonneau, Anaëlle; Pignol, Cécile; Chapron, Emmanuel; Vannière, Boris; Sabatier, Pierre


    In this paper we review the scientific efforts that were led over the last decades to reconstruct geomorphic patterns from continuous alpine lake sediment records. Whereas our results point a growing importance of humans as erosion forcing factors, we will focus here on climate-related processes. Our main dataset is made of a regional approach which was led without any a priori regarding erosion forcing factors. We hence integrated a set of sediment sequences from various environment along an altitudinal gradient from 200 up to 2400m asl in Northern French Alps. Altogether our data point climate change as one of the main factor of erosion variability. In particular, the last two cold spells that occurred during the early middle age (Dark Age) and between the 14th and the 20th century AD (Little Ice Age) appear to be outstanding compared to any other periods of enhanced erosion along the Holocene. The climatic forcing of those erosion phases is supported by an increase in the contribution of glacier-eroded material at a regional scale. At local scales, our data also point the growing importance, since at least the mid Bronze Age (ca. 3500 cal. BP) of human activities as a major erosion factor. This influence peaked during the late Iron Age and Antiquity periods (200 BC - 400 AD) when we record a regional generalised period of enhanced erosion in response to the development of pasturing activities. Thanks to provenance and weathering markers, we evidenced a strong relationship between the changes in ecosystems, soil development and erosion patterns. We hence showed the vegetal colonisation of bared soil led to a period of intense weathering while new soils were under formation between 11,000 and 8,000 cal. BP. Soils then knew an optimum until the onset of the Neoglacial at ca. 4,500 cal. BP prior to decline under both climate and human pressures. Altogether our data point the complexity of processes that affected the Earth critical zone along the Holocene. However

  13. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks.

    Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Liu, Yi; Yu, Guang-Bin; Deng, Hong; Wu, Sheng-Chun; Wong, Ming-Hung


    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (<63 μm) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous.

  14. Dynamics of phytoplankton pigments in water and surface sediments of a large shallow lake

    Ilmar Tõnno


    Full Text Available Our aim was to find out to which extent fossil phytoplankton pigments in the large shallow and turbid Lake Võrtsjärv carry information on the history of phytoplankton communities. For this purpose we examined how the changes in the pigment composition of surface sediments follow their changes in the water column. Depth-integrated lake water and surface sediment samples were collected weekly in May–October 2007. Considering cyanobacterial and diatom dominance in phytoplankton, we analysed fucoxanthin, diadinoxanthin and diatoxanthin as marker pigments for diatoms, zeaxanthin as a marker pigment for total cyanobacteria and canthaxanthin as a marker pigment for colonial cyanobacteria. Chlorophyll a and its derivative pheophytin a were applied as indicators for total phytoplankton. The dynamics of phytoplankton pigments in surface sediments generally did not follow their dynamics in the water column, possibly due to intensive resuspension and a high sedimentation rate in a large and shallow lake. It was noticed that the surface sediment carries information on pigment degradation intensity and on weight and size characteristics of phytoplankton cells, which affect their sinking and floating velocities. Higher pigment contents of sediment in spring were presumably caused by lower resuspension due to high water level and slower degradation in cold water. Pheophytin a and the marker pigments of cyanobacteria were found to be persistent against degradation in upper sediment layers, which makes them useful indicators for tracking the historical changes in phytoplankton communities also in a shallow lake. Sharp decrease in chemically unstable pigment contents between the sediment surface and deeper layers indicates that only the uppermost sediment surface is resuspended in Lake Võrtsjärv. The transformation of the diatom marker carotenoid diadinoxanthin to diatoxanthin was found to occur mainly in sediments and not in the water column, and the

  15. Laboratory experiment to determine phosphate release rates from sediments of a formerly oligotrophic lake (Silbersee, Cuxhaven)

    Elmarami, Hatem; Greskowiak, Janek; Hamann, Enrico; Massmann, Gudrun


    The Silbersee is a small, formerly oligotrophic lake in northwestern Germany which still contains rare character species for oligotrophic lakes (Isoëtes lacustris, Littorella uniflora) threatened by eutrophication. It was suspected that the lake sediments and the redox conditions in the hypolimnon play an important role with regard to eutrophication, potentially releasing phosphorus (P) into the water column. This was the motivation to conduct experiments to estimate the release rate of phosphorus into the lake. It had been noted that the P concentrations in the bottom water were higher during summer in the stagnation phase, when conditions turned sulfidic. Eight sediment cores were taken with a Mondsee-corer (manufactured by UWITEC) at different sites of the lake. The thickness of the sediment within the cores ranged from 15cm to 35 cm and were overlying by approximately 40cm of lake water water. The headspace was approximately 10cm. The cores were stored in a fridge first under oxic, then under anoxic conditions as observed in the lake bottom water in the different seasons. Redox conditions were maintained by bubbling with oxygen and nitrogen gas during the respective time periods. During the experiment, the temperature was held constant to match the water temperature measured at the bottom of the lake (~ 7±1°C). Concentrations of total phosphorus (TP) and dissolved phosphorus (DP), iron (Fe) and dissolved oxygen (DO) as well as pH were measured under oxic and anoxic conditions in the water column. The results showed that TP, DP and Fe concentrations were higher under anoxic conditions than under oxic conditions. The observed increase of phosporous in the water column during the anoxic phase was presumably a result of (i) reductive Fe-oxides dissolution and the corresponding loss of sorption sites and (ii) desorption of phosphorous via surface complexation reactions due to pH changes during the experiment.

  16. Linking Sediment Microbial Communities to Carbon Cycling in High-Latitude Lakes

    Emerson, J. B.; Varner, R. K.; Johnson, J. E.; Owusu-Dommey, A.; Binder, M.; Woodcroft, B. J.; Wik, M.; Freitas, N. L.; Boyd, J. A.; Crill, P. M.; Saleska, S. R.; Tyson, G. W.; Rich, V. I.


    It is well recognized that thawing permafrost peatlands are likely to provide a positive feedback to climate change via CH4 and CO2 emissions. High-latitude lakes in these landscapes have also been identified as sources of CH4 and CO2 loss to the atmosphere. To investigate microbial contributions to carbon loss from high-latitude lakes, we characterized sediment geochemistry and microbiota via cores collected from deep and shallow regions of two lakes (Inre Harrsjön and Mellersta Harrsjön) in Arctic Sweden in July, 2012. These lakes are within the Stordalen Mire long-term ecological area, a focal site for investigating the impacts of climate change-related permafrost thaw, and the lakes in this area are responsible for ~55% of the CH4 loss from this hydrologically interconnected system. Across 40 samples from 4 to 40 cm deep within four sediment cores, Illumina 16S rRNA gene sequencing revealed that the sedimentary microbiota was dominated by candidate phyla OP9 and OP8 (Atribacteria and Aminicenantes, respectively, including putative fermenters and anaerobic respirers), predicted methanotrophic Gammaproteobacteria, and predicted methanogenic archaea from the Thermoplasmata Group E2 clade. We observed some overlap in community structure with nearby peatlands, which tend to be dominated by methanogens and Acidobacteria. Sediment microbial communities differed significantly between lakes, by overlying lake depth (shallow vs. deep), and by depth within a core, with each trend corresponding to parallel differences in biogeochemical measurements. Overall, our results support the potential for significant microbial controls on carbon cycling in high-latitude lakes associated with thawing permafrost, and ongoing metagenomic analyses of focal samples will yield further insight into the functional potential of these microbial communities and their dominant members.

  17. Ancient DNA from lake sediments: Bridging the gap between paleoecology and genetics

    Lumibao Candice Y


    Full Text Available Abstract Background Quaternary plant ecology in much of the world has historically relied on morphological identification of macro- and microfossils from sediments of small freshwater lakes. Here, we report new protocols that reliably yield DNA sequence data from Holocene plant macrofossils and bulk lake sediment used to infer ecological change. This will allow changes in census populations, estimated from fossils and associated sediment, to be directly associated with population genetic changes. Results We successfully sequenced DNA from 64 samples (out of 126 comprised of bulk sediment and seeds, leaf fragments, budscales, and samaras extracted from Holocene lake sediments in the western Great Lakes region of North America. Overall, DNA yields were low. However, we were able to reliably amplify samples with as few as 10 copies of a short cpDNA fragment with little detectable PCR inhibition. Our success rate was highest for sediments Conclusions An ability to extract ancient DNA from Holocene sediments potentially allows exciting new insights into the genetic consequences of long-term environmental change. The low DNA copy numbers we found in fossil material and the discovery of multiple sequence variants from single macrofossil extractions highlight the need for careful experimental and laboratory protocols. Further application of these protocols should lead to better understanding of the ecological and evolutionary consequences of environmental change.

  18. Diploptene δ13C values from contemporary thermokarst lake sediments show complex spatial variation

    Davies, Kimberley L.; Pancost, Richard D.; Edwards, Mary E.; Anthony, Katey M. Walter; Langdon, Peter G.; Chaves Torres, Lidia


    Cryospheric changes in northern high latitudes are linked to significant greenhouse gas flux to the atmosphere, for example, methane that originates from organic matter decomposition in thermokarst lakes. The set of pathways that link methane production in sediments, via oxidation in the lake system, to the flux of residual methane to the atmosphere is complex and exhibits temporal and spatial variation. The isotopic signal of bacterial biomarkers (hopanoids, e.g. diploptene) in sediments has been used to identify contemporary ocean-floor methane seeps and, in the geological record, periods of enhanced methane production (e.g. the PETM). The biomarker approach could potentially be used to assess temporal changes in lake emissions through the Holocene via the sedimentary biomarker record. However, there are no data on the consistency of the signal of isotopic depletion in relation to source or on the amount of noise (unexplained variation) in biomarker values from modern lake sediments. We assessed methane oxidation as represented by the isotopic signal of biomarkers from methane oxidising bacteria (MOB) in multiple surface sediment samples in three distinct areas known to emit varying levels of methane in two shallow Alaskan thermokarst lakes. Diploptene was present and had δ13C values lower than -38 ‰ in all sediments analysed, suggesting methane oxidation was widespread. However, there was considerable variation in δ13C values within each area. The most 13C-depleted diploptene was found in an area of high methane ebullition in Ace Lake (diploptene δ13C values between -68.2 and -50.1 ‰). In contrast, significantly higher diploptene δ13C values (between -42.9 and -38.8 ‰) were found in an area of methane ebullition in Smith Lake. δ13C values of diploptene between -56.8 and -46.9 ‰ were found in the centre of Smith Lake, where ebullition rates are low but diffusive methane efflux occurs. The small-scale heterogeneity of the samples may reflect patchy

  19. Aeolian particle transport inferred using a ~150-year sediment record from Sayram Lake, arid northwest China

    Long Ma


    Full Text Available We studied sediment cores from Sayram Lake in the Tianshan Mountains of northwest China to evaluate variations in aeolian transport processes over the past ~150 years. Using an end-member modeling algorithm of particle size data, we interpreted end members with a strong bimodal distribution as having been transported by aeolian processes, whereas other end members were interpreted to have been transported by fluvial processes. The aeolian fraction accounted for an average of 27% of the terrigenous components in the core. We used the ratio of aeolian to fluvial content in the Sayram Lake sediments as an index of past intensity of aeolian transport in the Tianshan Mountains. During the interval 1910-1930, the index was high, reflecting the fact that dry climate provided optimal conditions for aeolian dust transport. From 1930-1980, the intensity of aeolian transport was weak. From the 1980s to the 2000s, aeolian transport to Sayram Lake increased. Although climate in northwest China became more humid in the mid-1980s, human activity had by that time altered the impact of climate on the landscape, leading to enhanced surface erosion, which provided more transportable material for dust storms. Comparison of the Lake Sayram sediment record with sediment records from other lakes in the region indicates synchronous intervals of enhanced aeolian transport from 1910 to 1930 and 1980 to 2000.

  20. Environmental evidence of fossil fuel pollution in Laguna Chica de San Pedro lake sediments (Central Chile)

    Chirinos, L. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile)]. E-mail:; Rose, N.L. [Environmental Change Research Centre, University College London, 26 Bedford Way, London WG1HOAP (United Kingdom); Urrutia, R. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Munoz, P. [Departamento de Biologia Marina, Universidad Catolica del Norte, Larrondo 1281, Coquimbo (Chile); Torrejon, F. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Torres, L. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Cruces, F. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Araneda, A. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Zaror, C. [Facultad de Ingenieria Quimica, Universidad de Concepcion, Concepcion (Chile)


    This paper describes lake sediment spheroidal carbonaceous particle (SCP) profiles from Laguna Chica San Pedro, located in the Biobio Region, Chile (36{sup o} 51' S, 73{sup o} 05' W). The earliest presence of SCPs was found at 16 cm depth, corresponding to the 1915-1937 period, at the very onset of industrial activities in the study area. No SCPs were found at lower depths. SCP concentrations in Laguna Chica San Pedro lake sediments were directly related to local industrial activities. Moreover, no SCPs were found in Galletue lake (38{sup o} 41' S, 71{sup o} 17.5' W), a pristine high mountain water body used here as a reference site, suggesting that contribution from long distance atmospheric transport could be neglected, unlike published data from remote Northern Hemisphere lakes. These results are the first SCP sediment profiles from Chile, showing a direct relationship with fossil fuel consumption in the region. Cores were dated using the {sup 21}Pb technique. - The lake sediment record of SCPs shows the record of fossil-fuel derived pollution in Central Chile.

  1. Polycyclic aromatic hydrocarbon composition in soils and sediments of high altitude lakes

    Grimalt, Joan O.; Drooge, Barend L. van; Ribes, Alejandra; Fernandez, Pilar; Appleby, Peter


    Polycyclic aromatic hydrocarbons (PAH) in lake sediments and nearby soils of two European high mountain regions, Pyrenees and Tatra, have been studied. Similar mixtures of parent PAH were observed in all cases, indicating predominance of airborne transported combustion products. Nevertheless, the composition of these atmospherically long-range transported PAH was better preserved in the superficial layers of soils than sediments. This difference points to significant PAH degradation process, e.g. during lake water column transport, before accumulation in the latter. Post-depositional transformation was also different in both types of environmental compartments. Thus, lake sediments exhibit higher preservation of the more labile PAH involving lower degree of post-depositional oxidation. However, they also show the formation of major amounts of perylene by diagenetic transformation in the deep sections. This compound is not formed in soils where downcore enrichments of phenanthrene are observed, probably as a consequence of diagenetic aromatization of diterpenoids.

  2. Estimation of sediment sources using selected chemical tracers in the Perry lake basin, Kansas, USA

    Juracek, K.E.; Ziegler, A.C.


    The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), and reservoir bottom sediment were collected, chemically analyzed, and compared. The samples were sieved to isolate the nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclide cesium-137 (137Cs). On the basis of substantial and consistent compositional differences among the source types, total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), and 137Cs were selected for use in the estimation of sediment sources. To further account for differences in particle-size composition between the sources and the reservoir bottom sediment, constituent ratio and clay-normalization techniques were used. Computed ratios included TOC to TN, TOC to TP, and TN to TP. Constituent concentrations (TN, TP, TOC) and activities (137Cs) were normalized by dividing by the percentage of clay. Thus, the sediment-source estimations involved the use of seven sediment-source indicators. Within the Perry Lake Basin, the consensus of the seven indicators was that both channel-bank and surface-soil sources were important in the Atchison County Lake and Banner Creek Reservoir subbasins, whereas channel-bank sources were dominant in the Mission Lake subbasin. On the sole basis of 137Cs activity, surface-soil sources contributed the most fine-grained sediment to Atchison County Lake, and channel-bank sources contributed the most fine-grained sediment to Banner Creek Reservoir and Mission Lake. Both the seven-indicator consensus and 137Cs indicated that channel-bank sources were dominant for Perry Lake and that channel-bank sources

  3. Late Glacial and Holocene Paleoliminology of two temperate lakes inferred from sediment organic 13C chronology

    N A Lovan; R V Krishnamurthy


    The stable carbon isotope (13C) and elemental C/N ratios in Total Organic Carbon (TOC) extracted from radiometrically dated cores from two Midwestern USA lakes were determined to investigate the factors that control these values in temperate lakes. The range of 13C values ( -26 to -32%) and C/N ratios (mean value ∼ 10.8) are typical of values reported for other temperate lake organic matter in this region. In the core from Lake Winnebago, Wisconsin, a negative correlation was seen between the TOC and 13C, which can be interpreted in terms of a re-mixing and consumption of sedimented organic carbon along with rapid equilibration throughout the water column. No correlation was seen between the TOC and 13C in the record from Ladd Lake, Ohio, implying that in this latter lake productivity alone was not a singular process controlling the isotope ratio. Here, it is suggested that equilibrium conditions are maintained such that the DIC of the water is never depleted of aqueous CO2 during high organic production and the resulting 13C of the organic carbon lacks correlation with the TOC. Further, in this lake a fine resolution analysis was carried out which indicated a possible anthropogenic influence on the isotope ratio around times when human settlement (∼ 300 yrs ago) and enhanced agricultural practices ( ∼ 80 yrs ago) were significant. The study shows that carbon isotope studies are useful in paleolimnologic investigations.

  4. Role of storms and forestry practices in sedimentation in an Oregon Coast Range Lake

    Guerrero, F. J.; Richardson, K.; Hatten, J. A.; Wheatcroft, R. A.


    Contemporary harvesting practices have been shown to reduce sediment transport rates relative to historic practices; however, it is not well understood how these practices interact with climate to influence sediment flux and source. We are currently studying sedimentation rates in Loon Lake, in the Oregon Coast Range. The watershed of Loon Lake is 80% privately owned, and is therefore an ideal system for examining the effect of policy affected management shifts on water quality and sediment transport. We analyzed one 690cm core that represents about 1500yrs of sedimentation in the lake. We measured accumulation by layer thickness and character by proxies of elemental analysis, magnetic susceptibility, particle size, and bulk density. Radionuclides and radiocarbon dates provide an age model with depth downcore. Our preliminary results show that there is some evidence that the sedimentation rate in the lake decreased around the time of passing of the Oregon Forest Practices Act when climate is taken into account; pre-OFPA, the estimated mean sedimentation rate was 1.0 cm/year, and post-OFPA, the estimated mean sedimentation rate was 0.76 cm/year. Both of these sedimentation rates appear to be different than pre-European settlement period which averaged about 0.40 cm/year; however, this conclusion is preliminary. In general, it seems there is some evidence that the Best Management Practices instituted with OFPA are associated with lower sedimentation rates. In our presentation we will discuss the role of forestry and climate in changing these sedimentation rates and compare these modern sedimentation rates with sedimentation in the pre-settlement period.

  5. Impacts of Nitrate Input on Nitrous Oxide Production in Lake Sediments

    Ruder, C. K.; Schade, J. D.


    Denitrification in lake sediments removes nitrogen from the ecosystem and produces the greenhouse gas nitrous oxide (N2O) as a byproduct. However, little is understood about the rates and controls of N2O production in lake sediments. Agricultural activity in lake catchments often results in the runoff of nitrogen fertilizers, leading to increased N inputs in the form of nitrate (NO3-). This study evaluates the influence of nitrate input on N2O concentrations in a series of lakes across a range of agricultural land use intensities. We measured N2O concentrations in lakes across seasons, and also used lake sediment samples to perform anaerobic incubations with NO3- additions, with and without the addition of acetylene (blocking conversion of N2O to N2), to assess denitrification potentials and the rate of N2O production in sediments. Our results suggest that N2O concentrations are strongly impacted by the availability of NO3- across all agricultural land use intensities, with incubation NO3- additions leading to a marked increase in N2O production. However, sediments reacted differently by site in incubations without experimental additions of NO3- or acetylene, with half of the study lakes experiencing net N2O production and half exhibiting net N2O consumption over the course of the 24-hour incubation period. These results suggest the potential influence of sediment organic matter as a control on N2O concentrations. The positive influence of NO3- on N2O production is supported by observational data at each of the study sites, though water column total nitrogen (TN) appears to be a better indicator of dissolved N2O concentrations than aqueous NO3-, perhaps due to variations in internal N recycling. This study concludes that agricultural runoff of NO3- has the potential to enhance sediment N2O production; however, further investigation into the effects of sediment organic matter on N2O production, analysis of N2O vertical diffusion efficiency to link production rates

  6. Phosphorus mobility among sediments, water and cyanobacteria enhanced by cyanobacteria blooms in eutrophic Lake Dianchi.

    Cao, Xin; Wang, Yiqi; He, Jian; Luo, Xingzhang; Zheng, Zheng


    This study was focused on the phosphorus mobility among sediments, water and cyanobacteria in eutrophic Lake Dianchi. Four conditions lake water, water and algae, water and sediments, and three objects together were conducted to investigate the effects of cyanobacteria growth on the migration and transformation of phosphorus. Results showed a persistent correlation between the development of cyanobacterial blooms and the increase of soluble reactive phosphorus (SRP) in the lake water under the condition of three objects together. Time-course assays measuring different forms of phosphorus in sediments indicated that inorganic phosphorus (IP) and NaOH-P were relatively more easier to migrate out of sediment to the water and cyanobacteria. Further studies on phosphorus mobility showed that up to 70.2% of the released phosphorus could be absorbed by cyanobacteria, indicating that sediment is a major source of phosphorus when external loading is reduced. Time-course assays also showed that the development of cyanobacterial blooms promoted an increase in pH and a decrease in the redox potential of the lake water. The structure of the microbial communities in sediments was also significantly changed, revealed a great impaction of cyanobacterial blooms on the microbial communities in sediments, which may contribute to phosphorus release. Our study simulated the cyanobacterial blooms of Lake Dianchi and revealed that the cyanobacterial blooms is a driving force for phosphorus mobility among sediments, water and cyanobacteria. The outbreak of algal blooms caused deterioration in water quality. The P in the sediments represented a significant supply for the growth of cyanobacteria.

  7. Sourcing sediment using multiple tracers in the catchment of Lake Argyle, Northwestern Australia.

    Wasson, R J; Caitcheon, Gary; Murray, Andrew S; McCulloch, Malcolm; Quade, Jay


    Control of sedimentation in large reservoirs requires soil conservation at the catchment scale. In large, heterogeneous catchments, soil conservation planning needs to be based on sound information, and set within the framework of a sediment budget to ensure that all of the potentially significant sources and sinks are considered. The major sources of sediment reaching the reservoir, Lake Argyle, in tropical northwestern Australia, have been determined by combining measured sediment fluxes in rivers with spatial tracer-based estimates of proportional contributions from tributaries of the main stream entering the lake, the Ord River. The spatial tracers used are mineral particle magnetics, the strontium isotopic ratio, and the neodymium isotopic ratio. Fallout of 137Cs has been used to estimate the proportion of the sediment in Lake Argyle eroded from surface soils by sheet and rill erosion, and, by difference, the proportion eroded from subsurface soils by gully and channel erosion. About 96% of the sediment in the reservoir has come from less than 10% of the catchment, in the area of highly erodible soils formed on Cambrian-age sedimentary rocks. About 80% of the sediment in the reservoir has come from gully and channel erosion. A major catchment revegetation program, designed to slow sedimentation in the reservoir, appears to have had little effect because it did not target gullies, the major source of sediment. Had knowledge of the sediment budget been available before the revegetation program was designed, an entirely different approach would have been taken.

  8. Extensional Tectonics Evidenced in Recent Sediments of Lake Van, Eastern Turkey

    Sengul, M. Alper; Koral, Hayrettin; Elmas, M. Ali


    The Lake Van region is characterized by NE-SW trending faults with a left-lateral normal-slip component, NW-SE trending faults with a right-lateral normal-slip component and E-W trending reverse/thrust-slip faults, suggesting a N-S trending compressional stress orientation. Tectonic effects in the region continue to be manifested by recent seismicity as in the earthquake of October 23, 2011 (Mw=7.1). Although this earthquake has not produced many earthquake-related surface deformation, evidences of recent tectonics are rather extensive in the Quaternary sediments surrounding the lake. Therefore ages of sediments are important in determining the timing of tectonic activity. Optically stimulated luminescence (OSL) method was used to determine the age of lake sediments to the north of the lake. Also, shells of gastropods available in the sediments are dated by C14. Ages suggest that to the NE of Lake Van youngest activity on the NW-SE trending Erciş Fault with right-lateral normal-slip component is to be 34 ka. Activity on other normal faults in the same area is dated between 10-14 ka and 20 ka. Also, samewhat to the south of this region in vicinity of the Canik area, reverse faulting is dated to be younger than 40 ka. All ages indicate the region has been affected during the Pleistocene locally by an extensional regime contemporaneously with the contractional regime. The evidence of a one meter dip-slip displacement measured on a fault plane in a quarry supports the view of local extension in the NE sector of the lake. Key Words: Lake Van, OSL dating, neotectonics, active tectonics

  9. Tectonic, climatic and hydrothermal control on sedimentation and water chemistry of northern Lake Malawi (Nyasa), Tanzania

    Branchu, Philippe; Bergonzini, Laurent; Delvaux, Damien; De Batist, Marc; Golubev, Vladimir; Benedetti, Marc; Klerkx, Jean


    This paper presents a multi-disciplinary characterisation of processes that influence sedimentation and lake water chemistry in the northern part of the Lake Malawi (or Lake Nyasa), East Africa. This characterisation is based on geophysical (heat-flow), tectonic, hydrological, hydrochemical (major elements, stable isotopes) and sedimentological (seismic profiles, core mineralogy) studies of data acquired from 1990 to 1994 during the CASIMIR project (Comparative Analysis of Sedimentary Infill Mechanisms in Rifts). Sub-surface activity is expressed through seismic and volcanic activity, as well as elevated heat-flow values, both beneath the lake and the surrounding area; hydrothermal activity is observed in the watershed however it was not clearly identified in the sub-lacustrine environment. Relatively high heat-flow values (80-90 mW/m 2) and the chemical composition of hydrothermal fluids in hot springs suggest the presence of a magmatic body at depth. The influence of Quaternary tectonic activity on sedimentary dynamics and infilling is observed not only on land but also in the lake through high-resolution seismic profiles. The main feature is a general tilting of the Kyela Plain as shown by a shift in the river course. The Quaternary stacking pattern of seven sedimentary sequences identified on a grid of high-resolution seismic reflection profiles represents a complete long-term lake-level cycle, from a lake lowstand at about 320 m below the present level to the present-day lake highstand. The North-Kiwira and Songwe River delta systems, composed of a number of stacked lobes, were developed in response to the interplay between gradual lake-level rise, tectonic movement and sediment input. The river dynamics is also recorded in a short core by a mineralogical evolution probably due to a decrease of detrital inputs from the Songwe River in response to hydroclimatic changes. Such changes are very important as this northern part of the watershed is considered as a

  10. Characterization of fecal indicator bacteria in sediments cores from the largest freshwater lake of Western Europe (Lake Geneva, Switzerland).

    Thevenon, Florian; Regier, Nicole; Benagli, Cinzia; Tonolla, Mauro; Adatte, Thierry; Wildi, Walter; Poté, John


    This study characterized the fecal indicator bacteria (FIB), including Escherichia coli (E. coli) and Enteroccocus (ENT), disseminated over time in the Bay of Vidy, which is the most contaminated area of Lake Geneva. Sediments were collected from a site located at ∼500 m from the present waste water treatment plant (WWTP) outlet pipe, in front of the former WWTP outlet pipe, which was located at only 300 m from the coastal recreational area (before 2001). E. coli and ENT were enumerated in sediment suspension using the membrane filter method. The FIB characterization was performed for human Enterococcus faecalis (E. faecalis) and Enterococcus faecium (E. faecium) and human specific bacteroides by PCR using specific primers and a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Bacterial cultures revealed that maximum values of 35.2 × 10(8) and 6.6 × 10(6)CFU g(-1) dry sediment for E. coli and ENT, respectively, were found in the sediments deposited following eutrophication of Lake Geneva in the 1970s, whereas the WWTP started operating in 1964. The same tendency was observed for the presence of human fecal pollution: the percentage of PCR amplification with primers ESP-1/ESP-2 for E. faecalis and E. faecium indicated that more than 90% of these bacteria were from human origin. Interestingly, the PCR assays for specific-human bacteroides HF183/HF134 were positive for DNA extracted from all isolated strains of sediment surrounding WWPT outlet pipe discharge. The MALDI-TOF MS confirmed the presence of general E. coli and predominance E. faecium in isolated strains. Our results demonstrated that human fecal bacteria highly increased in the sediments contaminated with WWTP effluent following the eutrophication of Lake Geneva. Additionally, other FIB cultivable strains from animals or adapted environmental strains were detected in the sediment of the bay. The approaches used in this research are valuable to assess the

  11. Holocene glacier fluctuations inferred from lacustrine sediment, Emerald Lake, Kenai Peninsula, Alaska

    LaBrecque, Taylor S.; Kaufman, Darrell S.


    Physical and biological characteristics of lacustrine sediment from Emerald Lake were used to reconstruct the Holocene glacier history of Grewingk Glacier, southern Alaska. Emerald Lake is an ice-marginal threshold lake, receiving glaciofluvial sediment when Grewingk Glacier overtops the topographic divide that separates it from the lake. Sub-bottom acoustical profiles were used to locate core sites to maximize both the length and resolution of the sedimentary sequence recovered in the 4-m-long cores. The age model for the composite sequence is based on 13 14C ages and a 210Pb profile. A sharp transition from the basal inorganic mud to organic-rich mud at 11.4 ± 0.2 ka marks the initial retreat of Grewingk Glacier below the divide of Emerald Lake. The overlaying organic-rich mud is interrupted by stony mud that records a re-advance between 10.7 ± 0.2 and 9.8 ± 0.2 ka. The glacier did not spill meltwater into the lake again until the Little Ice Age, consistent with previously documented Little Ice Ages advances on the Kenai Peninsula. The retreat of Grewingk Glacier at 11.4 ka took place as temperature increased following the Younger Dryas, and the subsequent re-advance corresponds with a climate reversal beginning around 11 ka across southern Alaska.

  12. Toxicity assessment of polycyclic aromatic hydrocarbons in sediments from European high mountain lakes.

    Quiroz, Roberto; Grimalt, Joan O; Fernández, Pilar


    Sediment quality guidelines and toxic equivalent factors have been used for assessment of the toxicity of sedimentary long-range atmospherically transported polycyclic aromatic hydrocarbons (PAHs) to the organisms living in high mountain European lakes. This method has provided indices that are consistent with experimental studies evaluating in situ sedimentary estrogenic activity or physiological response to AhR binding in fish from the same lakes. All examined lakes in north, central, west, northeast and southeast European mountains have shown sedimentary PAH concentrations that are above thresholds of no effect but only those situated in the southeast lakes district exhibited concentrations above the indices of probable effects. These mountains, Tatras, are also those having PAH concentrations of highest activity for AhR binding. Chrysene+triphenylene, dibenz[a]anthracene, benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene are the main compounds responsible for the observed toxic effects. Copyright 2010 Elsevier Inc. All rights reserved.

  13. Microplastic pollution of lakeshore sediments from remote lakes in Tibet plateau, China.

    Zhang, Kai; Su, Jing; Xiong, Xiong; Wu, Xiang; Wu, Chenxi; Liu, Jiantong


    Tibetan Plateau is known as the world's third pole, which is characterized by a low population density with very limited human activities. Tibetan Plateau possesses the greatest numbers of high-altitude inland lakes in the world. However, no information is currently available on the characteristic of microplastic pollution in those lakes within this remote area. In this work, lakeshore sediments from four lakes within the Siling Co basin in northern Tibet were sampled and examined for microplastics (plastic products. Polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride were identified from the microplastic samples using laser Raman spectroscopy, and oxidative and mechanical weathering textures were observed on the surface of microplastics using scanning electron microscope. These results demonstrate the presence of microplastics even for inland lakes in remote areas under very low human impact, and microplastic pollution can be a global issue.

  14. [Variation of nitrogen during the high suspended sediments concentration water supply in an artificial shallow lake].

    Chen, You-yuan; Shen, Yu; Yang, Shi-ying


    The effect of water quality and suspended sediments in the process of water supply is of an increasing concern recently in an artificial shallow lake. The water supply from the Yellow River to Dongchang Lake happened on April 23rd to 25th, 2012. The synchronous monitoring of flow velocity, suspended sediment concentration, dissolved nitrogen and particulate nitrogen concentration was conducted during the three days in five monitoring sites of the longitudinal profile from inlet to outlet. The spatio-temporal variation of nitrogen and the relationship between nitrogen concentration and suspended sediment concentration was analyzed. Moreover, the analysis of different nitrogen forms in surface water and bottom sediment was also made in the whole lake before and after the water supply. Results showed that the process of water supplement had an obvious effect on flow velocities and suspended sediment concentrations around the inlet area. The influence area was a limited scope. The spatial distribution of nitrogen presented a certain concentration gradient along the flow direction. Around the water inlet, concentrations of all nitrogen forms in water and bottom sediment was higher than those in other lake zones. The amplitude of variation of all nitrogen concentrations in surface water, suspended sediments showed a decreasing trend from water inlet to outlet. And concentrations of total dissolved and particulate nitrogen increased at different ratios after water supply in the lake. Total particulate nitrogen concentration increase was higher. It revealed the water supply of the Yellow River had a great influence on lake water. The dissolved nitrogen was the main nitrogen form in water supply. The ratio of total dissolved nitrogen to particulate nitrogen was 7.3 : 1. Nitrate was the primary form in dissolved nitrogen, and ammonium was the primary form in particulate nitrogen, respectively. The correlation between concentration of suspended sediments and ammonium, total

  15. Using public participation to sample trace metals in lake surface sediments: the OPAL Metals Survey.

    Turner, S D; Rose, N L; Goldsmith, B; Bearcock, J M; Scheib, C; Yang, H


    Members of the public in England were invited in 2010 to take part in a national metals survey, by collecting samples of littoral sediment from a standing water body for geochemical analysis. To our knowledge, this is the first national sediment metals survey using public participation and reveals a snapshot of the extent of metals contamination in ponds and lakes across England. Hg, Ni, Cu, Zn and Pb concentrations exceeding sediment quality guidelines for the health of aquatic biota are ubiquitous in ponds and lakes, not just in areas with a legacy of industrial activity. To validate the public sampling approach, a calibration exercise was conducted at ten water bodies selected to represent a range of lakes found across England. Sediment concentrations of Hg, Ni, Cu, Zn and Pb were measured in samples of soil, stream and littoral and deep water sediment to assess inputs. Significant differences between littoral sediment metal concentrations occur due to local variability, but also organic content, especially in upland, peat soil catchments. Variability of metal concentrations between littoral samples is shown to be low in small (metal contamination in standing waters. However, the heterogeneity of geology, soils and history/extent of metal contamination in the English landscape, combined with the random nature of sample collection, shows that systematic sampling for evaluating the full extent of metal contamination in lakes is still required.

  16. [Suspension-sedimentation of sediment and release amount of internal load in Lake Taihu affected by wind].

    Pang, Yong; Yan, Run-run; Yu, Zhong-bo; Li, Yi-ping; Li, Rui-ling


    The water quality in Meiliang Bay of the Taihu Lake was totally tested five times in the four seasons. The suspension samples were obtained by using a sediment trap. The sediment settling flux and resuspended flux were calculated according to the observation data by using Gansith formula, and the relationships between these fluxes and wind speeds were established. Seven experiments were conducted in Laboratory for hydrostatic settling behavior of suspended matter affected by different wind speeds in Lake Taihu. The hydrostatic settling fluxes of suspended matter were calculated and the relationships between the fluxes and suspended matter concentrations were established. Base on these works, the suspension-sedimentation process was decomposed and generalized according to the critical wind speed of 3.7 m/s. Daily sediment resuspended amount and settling amount of the year 2005 was calculated and annual average release amount of internal load in Lake Taihu was estimated using the wind data of nearly 10 years. The results indicate that daily release amount of internal load in Lake Taihu significantly influenced by wind and have the same trend of change with wind, while the release amount of different nutrients in the same condition are different. The Lake Taihu has an annual average release amount of internal load with COD 49,600 t, TN 7773.0 t and TP 275.5 t, of which summer has the markedly highest release amount than other seasons.

  17. Continuous and episodic sedimentation in western Norwegian fjord lakes. A Holocene climatic perspective


    A Holocene chronology of hazardous events has been constructed in parallel with a new record of glacier variability from inner Nordfjord in western Norway, based on the analysis of seismic profiles and sediment cores from the lakes Oldevatnet (8 km2), Nerfloen (1 km2) and Oppstrynsvatnet (30 km2). In paper I the frequency of episodic sedimentation events over the last 7300 years was investigated in a sediment core retrieved from Oldevatnet in inner Nordfjord, western Norway....

  18. Assessment of Water and Sediment Physical-Chemical Composition in the West Coast of Maracaibo Lake

    Jorge Moronta-Riera


    Full Text Available The objective of this investigation was to determine the physical and chemical composition of the water streams and sediments of the Maracaibo Lake in three sampling areas located in Tía Juana, Lagunillas and Ceuta in order to know the level of contamination and assess water quality based on permissible values established by the 883 Decree. The results indicate that the overall hydrocarbon concentrations in the water and sediments are above permissible levels. It is concluded that petroleum prospection is the root cause of the lake contamination.

  19. Application of geoinformation techniques to determine zones of sediment resuspension induced by wind waves in lakes (using two lakes from Northern Poland as examples

    Bajkiewicz-Grabowska Elżbieta


    Full Text Available Resuspension in lakes affects the quality of lake water. It is possible to model this process and visualize its outcomes using GIS tools. An assessment of the size of the zone of sediment resuspension was made for two lakes located in Northern Poland threatened by rapid eutrophication. For each of the lakes, four simulations using two methods for determining the effective wind length (F (Model 1 and Model 2 and two methods for determining the wind wavelength (Lw (Model A and Model B were performed. The analysis, taking into account the morphometry of the studied lakes and anemometric conditions, indicated that the differentiator is the applied simulation method of calculating the wavelength caused by the wind. The analysis is theoretical in nature and the results need to be verified in the field..

  20. Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta.

    Korosi, J B; Irvine, G; Skierszkan, E K; Doyle, J R; Kimpe, L E; Janvier, J; Blais, J M


    The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ~1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies.

  1. The sediments of lake on the Ardley Island, Antarctica:Identification of penguin-dropping soil Sun Liguang


    During CHINARE-15(Dec. 1998 - Mar. 1999), a lake core 67. 5 cm in length, was sampled in Y2 lake, which is located on the Ardley Island, Antarctica.The concentrations of some chemical elements in Y2 lake sediments were analyzed.According to comparative research on elementary characters of sediments in Antarctic West Lake, fresh penguin dropping as well as guano soil on the Ardley Island and Pacific Island in South China Sea, it presents that the Y2 lake sediments were ameliorated by penguin dropping. The result of element cluster analysis shows that the type elements in the sediment impacted by penguin dropping include Sr, F, S,P,Ca,Se,Cu, Zn and Ba. This can provide a base for further interpreting the climatic and environmental event recorded in the sediment.

  2. Detecting river sediments to assess hazardous materials at volcanic lake using advanced remote sensing techniques

    Saepuloh, Asep; Fitrianingtyas, Chintya


    The Toba Caldera formed from large depression of Quaternary volcanism is a remarkable feature at the Earth surface. The last Toba super eruptions were recorded around 73 ka and produced the Youngest Toba Tuff about 2,800 km3. Since then, there is no record of significant volcanic seismicity at Toba Volcanic Complex (TVC). However, the hydrothermal activities are still on going as presented by the existence of hot springs and alteration zones at the northwest caldera. The hydrothermal fluids probably containing some chemical compositions mixed with surficial water pollutant and contaminated the Toba Lake. Therefore, an environmental issues related to the existence of chemical composition and degradation of water clearness in the lake had been raised in the local community. The pollutant sources are debatable between natural and anthropogenic influences because some human activities grow rapidly at and around the lake such as hotels, tourisms, husbandry, aquaculture, as well as urbanization. Therefore, obtaining correct information about the source materials floating at the surface of the Toba Lake is crucial for environmental and hazard mitigation purposes. Overcoming the problem, we presented this paper to assess the source possibility of floating materials at Toba Lake, especially from natural sources such as hydrothermal activities of TVC and river stream sediments. The Spectral Angle Mapper (SAM) techniques using atmospherically corrected of Landsat-8 and colour composite of Polarimetric Synthetic Aperture Radar (PolSAR) were used to map the distribution of floating materials. The seven ground truth points were used to confirm the correctness of proposed method. Based on the SAM and PolSAR techniques, we could detect the interface of hydrothermal fluid at the lake surfaces. Various distributions of stream sediment were also detected from the river mouth to the lake. The influence possibilities of the upwelling process from the bottom floor of Toba Lake were also

  3. Effects of sample mass and macrofossil type on radiocarbon dating of arctic and boreal lake sediments

    Oswald, W W; Anderson, P M; Brown, T A; Brubaker, L B; Hu, F S; Lozhkin, A V; Tinner, W; Kaltenrieder, P


    Dating lake sediments by accelerator mass spectrometry (AMS) {sup 14}C analysis of plant macrofossils overcomes one of the main problems associated with dating bulk sediment samples, the presence of old organic matter. Even so, many AMS dates from arctic and boreal sites appear to misrepresent the age of the sediment. To understand the nature of these apparent dating anomalies better, we conducted a series of {sup 14}C dating experiments using samples from Alaskan and Siberian lake-sediment cores. First, to test whether our analytical procedures introduced a sample-mass bias, we obtained {sup 14}C dates for different-sized pieces of single woody macrofossils. In these sample-mass experiments, sized statistically equivalent ages were found for samples as small as 0.05 mg C. Second, to assess whether macrofossil type influenced dating results, we conducted sample-type experiments in which {sup 14}C dates were obtained for different macrofossil types sieved from the same depth in the sediment. We dated materials from multiple levels in sediment cores from Upper Capsule Lake (North Slope, northern Alaska) and Grizzly Lake (Copper River Basin, southern Alaska), and from single depths in other records from northern Alaska. In several of the experiments there were significant discrepancies between dates for different plant tissues, and in most cases wood and charcoal were older than other macrofossil types, usually by several hundred years. This pattern suggests that {sup 14}C dates for woody macrofossils may misrepresent the age of the sediment by centuries, perhaps due to their longer terrestrial residence time and the potential in-built age of long-lived plants. This study identifies why some {sup 14}C dates appear to be inconsistent with the overall age-depth trend of a lake-sediment record, and it may guide the selection of {sup 14}C samples in future studies.

  4. A First Evaluation of LANDSAT TM Data to Monitor Suspended Sediments in Lakes. [Lake Chicot, Arkansas

    Schiebe, F. R.; Ritchie, J. C.; Boatwright, G. O.


    The use of LANDSAT to monitor and track changes in the water quality of Lake Chicot, Arizona was assessed using MSS and TM digital data from nine water sites. Results show that: (1) TM Bands 1, 2, 3, and 4 appear to be providing information on concentrations of particulate matter suspended in surface waters. These bands are also highly interrelated for water samples; (2) preliminary evaluation indicates that TM Band 3 showed the best relationship to surface suspended solids; (3) TM Bands 5 and 7 are useful for separating water from nonwater areas; (4) the MSS Bands 2 and 3 can be related to suspended solids in surface water, as has already been shown from previous LANDSAT research; and (5) analysis of TM Band 6 indicates that while synoptic temperature patterns may be discerned, the digital sensitivity to a two degree temperature difference is low.

  5. Estimation of sediment sources using selected chemical tracers in the Perry lake basin,Kansas,USA



    The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins.In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas,representative samples of channel-bank sources,surface-soil sources (cropland and grassland),and reservoir bottom sediment were collected,chemically analyzed,and compared.The samples were sieved to isolate the <63μ m fraction and analyzed for selected nutrients (total nitrogen and total phosphorus),organic and total carbon,25 trace elements,and the radionuclide cesium-137 (137Cs).On the basis of substantial and consistent compositional differences among the source types,total nitrogen (TN),total phosphorus (TP),total organic carbon (TOC),and 137Cs were selected for use in the estimation of sediment sources.To further account for differences in particle-size composition between the sources and the reservoir bottom sediment,constituent ratio and clay-normalization techniques were used.Computed ratios included TOC to TN,TOC to TP,and TN to TP.Constituent concentrations (TN,TP,TOC) and activities (137Cs) were normalized by dividing by the percentage of clay.Thus,the sediment-source estimations involved the use of seven sediment-source indicators.Within the Perry Lake Basin,the consensus of the seven indicators was that both channel-bank and surface-soil sources were important in the Atchison County Lake and Banner Creek Reservoir subbasins,whereas channel-bank sources were dominant in the Mission Lake subbasin.On the sole basis of 137Cs activity,surface-soil sources contributed the most fine-grained sediment to Atchison County Lake,and channel-bank sources contributed the most fine-grained sediment to Banner Creek Reservoir and Mission Lake.Both the seven-indicator consensus and 137Cs indicated that channelbank sources were dominant for Perry Lake and that channel

  6. Complex Holocene Sedimentation and Erosion in Deep Basins of Lake Superior

    Colman, S. M.; Wattrus, N. J.


    Little sediment accumulates on the lake floor of most of the Laurentian Great Lakes in water less than about 100 m deep. Such sediment is thought to be resuspended by waves and currents and "focused" onto the deeper lake floor. New high-resolution CHIRP seismic-reflection data in central Lake Superior suggests that Holocene sedimentation has been considerably more complex there. The late- and post- glacial stratigraphy in Lake Superior consists of glacial-lacustrine red varves overlain by gray varves. The glacial-lacustrine section is capped by poorly laminated, fine-grained, gray Holocene muds. In many areas, the entire post-glacial section is cut by polygonal fractures and faults related to dewatering or syneresis. Our new seismic-reflection data from water depths of 150-250 m indicate that the upper surface of the varved section is extensively eroded, both by planation of varves draped over bathymetric highs and by widespread channeling. The cause of this pervasive erosion is not known, but it may be related to the sudden opening of a low outlet from the lake as the continental ice sheet retreated. Within the Holocene section, small to medium sized (2-4 m deep, 100-300 m wide) channels are formed, in some cases overlying the older channels in the varved section. Commonly, the Holocene channels cut directly into the underlying varved section. Both of these types of channels are partially to fully filled with Holocene sediments. Dipping reflections within the Holocene section suggest considerable complexity in Holocene sedimentation. Large parts of the study area contain only thin (<1 m) Holocene section and large areas contain none at all. All of these observations indicated a much more complex set of Holocene erosional and depositional processes in deep water than those implied by the simple focusing mechanism.

  7. Trimethylamine stimulated and dissolved organic matter inhibited methane production in sediment from the Poyang Lake, China.

    Wang, Jiajia; Liu, Chunying; Gong, Xiaofeng; Liu, Yuanmu; Chen, Chunli


    Methane (CH4) emitted from wetlands contributes significantly to the greenhouse effect. The Poyang Lake, the largest freshwater lake in China, is fed by five rivers and connects to the Yangtze River. The area of the lake fluctuates dramatically between drawdown and flood periods with large areas of wetlands. In order to understand the CH4 production capacity and factors that influence CH4 production in the wetland, a static closed chamber combined with a gas chromatograph technique was used to investigate the influence of substrates and electron acceptors on methanogenesis. The results showed that CH4 production capacity of sediments from the Poyang Lake was [Formula: see text] and it was stimulated by trimethylamine (TMA) to a great extent. Incubation temperature played a vital role on CH4 production in sediments and the optimum temperature for methanogenesis was 35°C. Minimum CH4 production capacity occurred with the addition of FeCl3, and the inhibitory effects of electron acceptors decreased in the sequence: FeCl3 > MnO2 > DOM > Fe2O3. In this study, DOM was demonstrated as one of the inhibitors to methanogenesis and TMA was the main substrate of methanogens in the sediments of the Poyang Lake whose pH value is 7.83.

  8. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.

    Ma, Long; Wu, Jinglu; Abuduwaili, Jilili; Liu, Wen


    Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.

  9. Mid-to-Late Holocene Hydrologic Variability in the Southeastern Mojave Desert Using Sediments from Ford Lake

    Mayer, S. A.; Kirby, M. E.; Anderson, W. T., Jr.; Stout, C.; Palermo, J. A.


    The focal point of most lacustrine studies in the Mojave National Preserve (MNP) to date has been on lakes fed by the Mojave River. The source of the Mojave River is found on the northern flank of the San Bernardino Mountains. Consequently, the lakes that receive these waters are predominantly responding to the winter-only coastal southwest United States climate (e.g., Kirby et al., 2015 - Silver Lake); to a lesser degree, these lakes are also influenced by the Mojave's bimodal winter/summer climate. Ford Lake, located in the southeastern Mojave Desert is a small closed basin lake with its drainage basin located exclusively within the Mojave Desert. Therefore, sediment collected from Ford Lake contains a 100% Mojave-only climate signal. A 2.18 m sediment core was collected from the lake's depocenter in May 2015. Sediment analyses at 1 cm contiguous intervals include: magnetic susceptibility (MS), percent total organic matter, percent total carbonate content, and grain size analysis; C:N ratios, C and N isotope (δ13C and δ15N) analyses, and macrofossil counts are determined at 2 cm intervals. The site's age model is based on accelerator mass spectrometry (AMS) radiocarbon ages from discrete organic macrofossils or bulk organic carbon. To deconvolve the coastal climate, winter-only signal from the Mojave-only climate signal the data from Ford Lake will be compared to one Mojave River fed lake (Silver) and several southern California lakes (Lower Bear, Lake Elsinore, Dry Lake, and Zaca Lake). Our results will be analyzed in the context of climate forcings such as insolation and ocean - atmosphere dynamics.

  10. Agricultural pesticides in Mississippi Delta oxbow lake sediments during autumn and their effects on Hyalella azteca.

    Lizotte, Richard E; Knight, Scott S; Bryant, Charles T; Smith, Sammie


    Agricultural pesticide contamination of sediments from five Mississippi Delta oxbow lakes and their effects and bioavailablity to Hyalella azteca were assessed during a low-application season-autumn. Three reference oxbow lakes were located in the White River National Wildlife Refuge (WRNWR), Arkansas and two impaired lakes, according to the US Environmental Agency Sect. 303 (d) Clean Water Act, were located in Mississippi. Surface sediment (top 5 cm) was collected at three sites within each lake and analyzed for 17 current and historic-use pesticides and metabolites. Chronic 28-day H. azteca sediment bioassays and pesticide body residue analyses were completed to determine the degree of biological responses and bioavailability. The greatest number of detectable pesticides in WRNWR and 303 (d) sediment samples was 9 and 12, respectively, with historic-use pesticide metabolite, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] ubiquitous. No significant (p > 0.05) differences in animal survival were observed among sites. Animal growth was significantly (p azteca with current-use pesticides detected at three sites; historic-use pesticides and metabolites detected at 11 sites. Animal body residues of a historic-use pesticide (dieldrin) and metabolite (p,p'-DDE) were associated with observed growth responses. Results show limited current-use pesticide contamination of sediments and H. azteca body tissues during autumn and that historic-use pesticides and metabolites are the primary contributors to observed biological responses.

  11. Remobilization and export of cadmium from lake sediments by emerging insects

    Currie, R.S.; Fairchild, W.L.; Muir, D.C.G. [Dept. of Fisheries and Oceans, Winnipeg, Manitoba (Canada). Freshwater Inst.


    Emerging insects including, Diptera, Odonata, Ephemeroptera, and Trichoptera were collected from Lake 382 (L382) in 1991 and 1992 to estimate quantitatively the export of Cd by aquatic insects from a natural system having elevated Cd concentrations in the water and sediment. L382 is a Canadian Shield lake, located within the Experimental Lakes Area in northwestern Ontario, that received experimental additions of Cd from 1987 to 1992. Emerging Diptera (mostly Chironomidae), Odonata, and Ephemeroptera had mean Cd concentrations of 1.41, 0.11, and 0.30 {micro}g/g wet weight, respectively. An estimated 1.32 to 3.90 g of Cd per year were exported from the sediments of L382 depending on the estimate of production rates used for these groups of insects. Approximately 0.05 to 0.17% of the whole-lake Cd load in L382 sediments was exported annually or 0.12 to 0.39% of the epilimnion Cd sediment load. Insect emergence may have resulted in greater Cd export from L382 relative to losses via the outflow. Cadmium exported from the sediments by insects may be remobilized and become more available to aquatic organisms or enter the terrestrial ecosystem and become available to insectivores.

  12. {sup 137}Cs and {sup 210}Pb inventories in soils and sediments from Chapala Lake (Mexico)

    Ruiz-Fernandez, A.C.; Perez-Bernal, L.H. [Unidad Academica Mazatlan, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico (Mexico); Sanchez-Cabeza, J.A. [Unidad Academica de Procesos Oceanicos y Costeros, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico (Mexico); Ontiveros-Cuadras, J.F. [Posgrado en Ciencias del Mar y Limnologia, Instituto de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico (Mexico)


    Chapala Lake is the largest natural freshwater reservoir in Mexico and it is located in Central Mexico, at 1524 m above sea level. The lake is considered to be fairly anthropized and it has experienced periods of extremely low water level as a result of recent climate change and water extraction. The study of recent manifestations of global change in Chapala Lake requires accurate {sup 210}Pb chronological reconstructions, taking into account the expected variability of sediment accumulation rates by using the Constant Flux model. For a reliable application of this dating model, it is important that {sup 210}Pb flux values in the lacustrine sedimentary record are in correspondence with the local atmospheric fluxes. With the aim to estimate the fluxes of the fallout radionuclides {sup 210}Pb and {sup 137}Cs in the region, sediment and soil cores were collected in the Chapala Lake. Sediment profiles were evaluated and estimated fluxes in sediments and soils were compared. Some geochemical properties (e.g. grain size distribution, organic matter concentration, XRF-derived elemental composition and magnetic susceptibility) were also evaluated to understand how diagenesis changes and sediment provenance can affect the {sup 210}Pb and {sup 137}Cs depth profiles and inventories. Document available in abstract form only. (authors)

  13. Biogenic and abiogenic polynuclear aromatic hydrocarbons in sediments from two remote Adirondack lakes

    Tan, Y. L.; Heit, M.


    Sediment cores from Sagamore Lake and Woods Lake in New York State's Adirondack Park, an area remote from industrial activities, were analyzed for polynuclear aromatic hydrocarbons (PAH) by high resolution gas chromatography/mass spectrometry (GC/MS). Their composition and distribution with depth in the sediment indicate that the parental PAH in the surface sediments are primarily produced by anthropogenic combustion of fossil fuels. Perylene in deep sediments is apparently transformed from natural precursors in the reducing environment, however, the exact precursors remain unknown. The rather even sediment distributions of the non-parental PAH differ from the parental, suggesting biogenic origins. Based on their chemical structures, retene and alkylated and partially hydrogenated phenanthrenes are believed to be biogenically converted from abietic acid; hydrochrysenes and hydropicenes, from pentacyclic triterpenes.

  14. Improved understanding of Diatom stratigraphy in a varved sediment through a sediment trap, lake monitoring and a catchment study

    Maier, D. B.


    Biological sediment remains reflect past lake surrounding conditions. Potential drivers of change in the biological sediment proxy can be environmental contributors like weather and temperature changes as well as man-made such as developments in agriculture and forestry. However we don't know how these different factors contribute to the biological sediment signal. Here we are monitoring a boreal lake with a varved sediment to understand how the biological signal of diatom remains is formed in the annually layered sediment. We compare the diatom stratigraphy with a sequential sediment trap. For a deeper understanding of the underlying mechanisms we look at three full years of bi-weekly monitoring of physical, chemical and biological parameters and 15 years of water stratification data. We seek to link the monitored in-lake processes with the yearly environmental characteristics. The diatom sediment stratigraphy of the two most abundant species Asterionella formosa and Fragilaria delicatissima indicates three periods with a contrasting trend for both species from 1975 until 2014. In the first period Asterionella formosa is almost not abundant spanning one decade (1975-1985), reaching elevated abundance with a decreasing trend in period 2 over the following 17 years to be followed by a tripling of Asterionella fromosa remains in the sediment during the third period. The opposite trend is found for Fragilaria delicatissima. Linking the recorded data with the corresponding sediment stratigraphy allows us to distinguish between weather changes and catchment disturbances as potential drivers for changes in a sedimentary diatom signal.

  15. Great Lakes Environmental Database (GLENDA)

    U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes area.

  16. Biological and chemical characterization of metal bioavailability in sediments from Lake Roosevelt, Columbia River, Washington, USA

    Besser, J.M.; Brumbaugh, W.G.; Ivey, C.D.; Ingersoll, C.G.; Moran, P.W.


    We studied the bioavailability and toxicity of copper, zinc, arsenic, cadmium, and lead in sediments from Lake Roosevelt (LR), a reservoir on the Columbia River in Washington, USA that receives inputs of metals from an upstream smelter facility. We characterized chronic sediment toxicity, metal bioaccumulation, and metal concentrations in sediment and pore water from eight study sites: one site upstream in the Columbia River, six sites in the reservoir, and a reference site in an uncontaminated tributary. Total recoverable metal concentrations in LR sediments generally decreased from upstream to downstream in the study area, but sediments from two sites in the reservoir had metal concentrations much lower than adjacent reservoir sites and similar to the reference site, apparently due to erosion of uncontaminated bank soils. Concentrations of acid-volatile sulfide in LR sediments were too low to provide strong controls on metal bioavailability, and selective sediment extractions indicated that metals in most LR sediments were primarily associated with iron and manganese oxides. Oligochaetes (Lumbriculus variegatus) accumulated greatest concentrations of copper from the river sediment, and greatest concentrations of arsenic, cadmium, and lead from reservoir sediments. Chronic toxic effects on amphipods (Hyalella azteca; reduced survival) and midge larvae (Chironomus dilutus; reduced growth) in whole-sediment exposures were generally consistent with predictions of metal toxicity based on empirical and equilibrium partitioning-based sediment quality guidelines. Elevated metal concentrations in pore waters of some LR sediments suggested that metals released from iron and manganese oxides under anoxic conditions contributed to metal bioaccumulation and toxicity. Results of both chemical and biological assays indicate that metals in sediments from both riverine and reservoir habitats of Lake Roosevelt are available to benthic invertebrates. These findings will be used as

  17. Sediment Particle Size Distribution and Its Environmental Significance in Lake Erhi,Yunnan Province

    陈敬安; 万国江; 等


    A closed or semi-closed plateau lake,whose sediment records can provide uw with plenty of fine and high resolution information,is a sensitive indicator of climatic and environmental changes.During the reconstruction of various short-time-scale climatic and environmental changes,the geochemical records in plateau-lake sediments are superior to other natural files.Based on fine dissection of the vertical profile of sediment particle sizes.this paper reveals the quasi-periodical changes of sediment particle sized,which indicates the quasi-periodical fluctuations of the regional climate.A synthetic anslysis of multiple indexes shows that sediment particle size is a more sensivtive and more effective index of climatic and environmental changes than other geochemical indexes.High content of>20μm sediment particles and low content of 2-10μm sediment particles indicate a warm-dry climate and conversely a cold-humid climate,and their ratio can be used as an effective index of climatic changes.Te basic climate succession in the region of Lake Rehai is characterized as being alternativlely warm-dry and cold-humid and it has been developing into a warm-dry climate as a whole.There exist at least 2 time-scale quasi-periodical fluctuations of the regional climate in Lake Erhai.At present,the region of Lake Erhai is at the end of the warm-dry period and at the beginning of a cold-humid period,so the temperature will go down and the water level will rise.

  18. Environmental change within the Balkan region during the past ca. 50 ka recorded in the sediments from lakes Prespa and Ohrid

    B. Wagner


    Full Text Available Lakes Prespa and Ohrid, in the Balkan region, are considered to be amongst the oldest lakes in Europe. Both lakes are hydraulically connected via karst aquifers. From Lake Ohrid, several sediment cores up to 15 m long have been studied over the last few years. Here, we document the first long sediment record from nearby Lake Prespa to clarify the influence of Lake Prespa on Lake Ohrid and the environmental history of the region. Radiocarbon dating and dated tephra layers provide robust age control and indicate that the 10.5 m long sediment record from Lake Prespa reaches back to 48 ka. Glacial sedimentation is characterized by low organic matter content and absence of carbonates in the sediments, which indicate oligotrophic conditions in both lakes. Holocene sedimentation is characterized by particularly high carbonate content in Lake Ohrid and by particularly high organic matter content in Lake Prespa, which indicates a shift towards more mesotrophic conditions in the latter. Long-term environmental change and short-term events, such as related to the Heinrich events during the Pleistocene or the 8.2 ka cooling event during the Holocene, are well recorded in both lakes, but are only evident in certain proxies. The comparison of the sediment cores from both lakes indicates that environmental change affects particularly the trophic state of Lake Prespa due to its lower volume and water depth.

  19. Weak chemical weathering during the Little Ice Age recorded by lake sediments


    Low magnetic susceptibility, low Sr content and hence high Rb/Sr ratio in the lake sediment sequence indicate a weak chemical weathering process under arid and cold climate of the Little Ice Age in a single closed lake watershed. According to different geochemical behavior between rubidium and strontium in earth surface processes, variation of Rb/Sr ratios in the lake sediment sequence can be used as an effective geochemical proxy with definite climatic significance of chemical weathering in watershed. Unlike chemical weathering process in tropic zone and modern temperate-humid climate, concordant changes in both Sr content and magnetic susceptibility with d18O values of Dunde ice core suggest that the weak chemical weathering was controlled by air temperature during the Little Ice Age maximum. After the Little Ice Age, chemical weathering intensity was controlled also gradually by precipitation with increasing in temperature.

  20. Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries.

    Thevenon, Florian; Graham, Neil D; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John


    This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents.

  1. Sources appointment and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Erhai Lake, a low-latitude and high-altitude lake in southwest China.

    Hezhong, Yuan; Enlou, Zhang; Qi, Lin; Rong, Wang; Enfeng, Liu


    Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed from the surficial sediments in Erhai Lake, a plateau lake in China. The results showed that except for acenaphthylene (Ace) Ace and Dibenz(a,h)anthracene (DBA), the central region contained individual PAHs at concentrations lower than those in other lake regions. Total concentration of the PAHs (ΣPAHs) in the sediments from Erhai Lake ranged from 32.42 to 558.53 mg/kg with a mean value of 256.70 mg/kg. The maximum value of ΣPAHs was observed in the north region of the lake and more than 10-fold higher than the minimum values. Moreover, high molecular weight (HMW) PAHs, especially 5-ring PAHs, accounted for higher ratios up to 76 % relative to other PAHs compound in almost all sampling sites. Molecular diagnostic ratios including anthtacene (Ant)/(Ant + phenanthrene (Phe)), fluoranthene (Flt)/(Flt + pyrene (Pyr)), benz(a)anthracene (BaA)/(BaA + chrysene (Chr)), and indeno(1,2,3-cd)pyrene (IPY)/(IPY + benz(g,h,i)perylene (BPE)) were recorded at all sampling sites and indicated that the origin of PAHs in Erhai Lake was predominately pyrolytic. Furthermore, principal component analysis with component dominating by HMW PAHs showed that combustion origins were the primary contamination sources of PAHs in the sediments of Erhai Lake. Finally, ecological risk assessment indicated that the sediments from Erhai Lake are exposed to potential low risk for ΣPAHs, and the ecological risk decreases in the order of northern region > southern region > central region.

  2. Occurrence and trends of selected nutrients, other chemical constituents, diatoms, and cyanobacteria in bottom sediment, Lake Maxinkuckee, northern Indiana

    Juracek, Kyle E.


    Bottom-sediment cores collected in 2013 were used to investigate the recent and predevelopment (pre-1863) occurrence of selected nutrients (total nitrogen and total phosphorus), carbon, 39 trace elements, diatoms, cyanobacterial akinetes, and 3 radionuclides in the bottom sediment of Lake Maxinkuckee, a kettle lake in northern Indiana. Total nitrogen concentrations in the recent sediment (since about 1970) were variable with no consistent trend indicated. Total phosphorus concentrations in the recent sediment generally were uniform from about 1970 to about 2000 and indicated consistent inputs to the lake during that time. Subsequently, the history of total phosphorus deposition apparently was obscured by postdepositional upward diffusion.

  3. Sediment composition, varve formation and paleolimnology of Lake Yoa, NE Chad

    Karls, Jens; Kröpelin, Stefan; Just, Janna; Kuper, Jan; Rethemeyer, Janet; Viehberg, Finn; Wennrich, Volker; Melles, Martin


    Lake Yoa (19.03° N / 20.31° E, NE Chad, 380 m a.s.l.) is a groundwater-fed lake in the central Sahara situated in a deflation hollow below an escarpment close to the Chadian-Libyan border. The lake persists since the onset of the Holocene "Green Sahara" 11,000 years ago. It has survived the end of the early to mid-Holocene wet phase until today due to extensive groundwater supply from the so-called Nubian Sandstone Aquifer System. Continuous lake sedimentation has generated an unparalleled depositional archive of Holocene climatic and environmental changes in the presently hyper-arid central Sahara, which is characterized by less than 10 mm of annual precipitation against an annual evaporation of more than 6,000 mm. An earlier 7.5 m long sediment core from Lake Yoa (OUNIK03/04) has provided unprecedented insight into the past 6,000 years cal BP (Kröpelin et al. 2008). Within the framework of the Collaborative Research Centre 806 "Our Way to Europe - Culture-Environment Interaction and Human Mobility in the Late Quaternary", the record was extended to the base of the lake sediments at a depth of 16.25 m below the lake floor in 2010 (core Co1240). Most of the sedimentary column is annually to sub-annually laminated. Varve counting resulted in a highly resolved robust chronology that is supported by AMS radiocarbon dating of various components (bulk sediment, bulk carbonate, humic acids, semi-aquatic plants and charcoal). The core material was examined in a multiproxy approach, including non-destructive geophysical (e.g. magnetic susceptibility) and elemental (XRF scanning) measurements as well as sedimentological, geochemical and paleontological analyses. The data not only give detailed information on changes in the lake body and catchment of Lake Yoa but also on the regional climate and environmental history during the past 11,000 years cal BP. Kröpelin et al. (2008). Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years. Science 320: 765

  4. Increased sediment oxygen flux in lakes and reservoirs: The impact of hypolimnetic oxygenation

    Bierlein, Kevin A.; Rezvani, Maryam; Socolofsky, Scott A.; Bryant, Lee D.; Wüest, Alfred; Little, John C.


    Hypolimnetic oxygenation is an increasingly common lake management strategy for mitigating hypoxia/anoxia and associated deleterious effects on water quality. A common effect of oxygenation is increased oxygen consumption in the hypolimnion and predicting the magnitude of this increase is the crux of effective oxygenation system design. Simultaneous measurements of sediment oxygen flux (JO2) and turbulence in the bottom boundary layer of two oxygenated lakes were used to investigate the impact of oxygenation on JO2. Oxygenation increased JO2 in both lakes by increasing the bulk oxygen concentration, which in turn steepens the diffusive gradient across the diffusive boundary layer. At high flow rates, the diffusive boundary layer thickness decreased as well. A transect along one of the lakes showed JO2 to be spatially quite variable, with near-field and far-field JO2 differing by a factor of 4. Using these in situ measurements, physical models of interfacial flux were compared to microprofile-derived JO2 to determine which models adequately predict JO2 in oxygenated lakes. Models based on friction velocity, turbulence dissipation rate, and the integral scale of turbulence agreed with microprofile-derived JO2 in both lakes. These models could potentially be used to predict oxygenation-induced oxygen flux and improve oxygenation system design methods for a broad range of reservoir systems.

  5. Determination of specific molecular markers of biomass burning in lake sediments

    Kirchgeorg, Torben; Schüpbach, Simon; Kehrwald, Natalie; McWethy, David; Barbante, Carlo


    Fire influences regional to global atmospheric chemistry and climate. Molecular markers of biomass burning archived in lake sediments are becoming increasingly important in paleoenvironmental reconstruction and may help determine interactions between climate and fire activity. One group of these molecular markers is the monosaccharide anhydrides levoglucosan, mannosan and galactosan. Several aerosol studies and recent ice core research use these compounds as a marker for biomass burning, but studies from lake sediment cores are rare. Previous sediment methods used gas chromatography - mass spectrometry and required derivatization of samples. Here, we present a high performance anion exchange chromatography-mass spectrometry method to allow separation and detection of the three monosaccharide anhydrides in lake sediments with implications for reconstructing past biomass burning events. We validated the method by quantifying levoglucosan, mannosan and galactosan in selected sediment core samples from Lake Kirkpatrick, New Zealand. The freeze-dried, milled and homogenized sediment samples were first extracted with methanol by pressurized solvent extraction, pre-concentrated and finally separated and analyzed by high performance anion exchange chromatography-mass spectrometry. We compared these isomers with macroscopic charcoal concentrations, as charcoal is a well-known proxy for biomass burning. In addition, we applied the method to a sediment core from Lake Petén Itzá, Guatemala to prove the suitability of these markers for reconstructing biomass burning history over the entire Holocene. In the Lake Kirkpatrick samples, levoglucosan, mannosan and galactosan concentrations significantly correlate with macroscopic charcoal concentrations. The three isomers are present in samples without any macroscopic charcoal, and may reflect the presence of microscopic charcoal. Levoglucosan/mannosan and levoglucosan/(mannosan+galactosan) ratios differ between samples with high

  6. Spatial distribution and risk assessment of heavy metals and As pollution in the sediments of a shallow lake.

    Deng, Jiancai; Wang, Yuansheng; Liu, Xin; Hu, Weiping; Zhu, Jinge; Zhu, Lin


    The concentrations and spatial distributions of eight heavy metals in surface sediments and sediment core samples from a shallow lake in China were investigated to evaluate the extent of the contamination and potential ecological risks. The results showed that the heavy metal concentrations were higher in the northern and southwestern lake zones than those in the other lake zones, with lower levels of As, Hg, Zn, Cu, Pb, Cr, and Ni primarily observed in the central and eastern lake regions and Cd primarily confined to areas surrounding the lake. The concentrations of the eight heavy metals in the sediment profiles tended to decrease with increasing sediment depth. The contents of Ni, Cu, Zn, Pb, and Cd in the surface sediment were approximately 1.23-18.41-fold higher than their background values (BVs), whereas the contents of Cr, As, and Hg were nearly identical to their BVs. The calculated pollution load index (PLI) suggested that the surface sediments of this lake were heavily polluted by these heavy metals and indicated that Cd was a predominant contamination factor. The comprehensive potential ecological risk index (PERI) in the surface sediments ranged from 99.2 to 2882.1, with an average of 606.1. Cd contributed 78.7 % to the PERI, and Hg contributed 8.4 %. Multivariate statistical analyses revealed that the surface sediment pollution with heavy metals mainly originated from industrial wastewater discharged by rivers located in the western and northwestern portion of the lake.

  7. Occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls and heavy metals in surface sediments from a large eutrophic Chinese lake (Lake Chaohu)

    He, Wei; Bai, Ze-Lin; Liu, Wen-Xiu


    Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ34PCBs) in Lake Cha......, and Hg were at levels of environmental concern. The sediment in the drinking water source area (DWSA) was threatened by heavy metals from other areas, and some fundamental solutions were proposed to protect the DWSA.......Surface sediment from large and eutrophic Lake Chaohu was investigated to determine the occurrence, spatial distribution, sources, and risks of polychlorinated biphenyls (PCBs) and heavy metals in one of the five biggest freshwater lakes in China. Total concentration of PCBs (Σ34PCBs) in Lake...... Chaohu was 672 pg g−1 dry weight (dw), with a range of 7 to 3999 pg g−1 dw, which was lower than other water bodies worldwide. The majority of heavy metals were detected at all sampling locations, except for Sr, B, and In. Concentrations of Al, Fe, Ca, Mn, Sr, Co, Zn, Cd, Pb, and Hg were similar...

  8. Anaerobic oxidation of methane in an iron-rich Danish freshwater lake sediment

    Nordi, Katrin á; Thamdrup, Bo; Schubert, Carsten J.


    Freshwater systems are identified as one of the main natural methane sources, but little is known about the importance of anaerobic oxidation of methane (AOM) in these systems. We investigated AOM in a lake sediment characterized by a high reactive iron content, normal sulfate concentrations in t...

  9. Increased accumulation of sulfur in lake sediments of the high Arctic

    Drevnick, Paul E.; Muir, Derek C.G.; Lamborg, Carl H.;


    stimulates dissimilatory sulfate reduction. The sulfide produced is stored in sediment (as acid volatile sulfide), converted to other forms of sulfur, or reoxidized to sulfate and lost to the water column. An acceleration of the sulfur cycle in Arctic lakes could have profound effects on important...

  10. Distribution of sterols and the sources of pollution in surface sediments of Ulungur lake, Xinjiang.

    Yao, Xiaorui; Lu, Jianjiang; Liu, Zilong; Ran, Dan; Huang, Yating


    Domestic sewage discharged into lakes brings great pressure to the ecological environment. This study selected sediment from an inland lake as a research object to evaluate pollution of the environment. Eight sterols were used to evaluate the content of pollutants, while the ratios of sterols were used as the index to analyze the sources of pollution. The correlations were analyzed between sterols and total organic carbon (TOC), salinity and particle size. The distribution and composition of sterol compounds were determined in 12 surface sediment samples collected from Ulungur lake. The total concentrations of detected sterols in the sediments ranged from 1.3 to 36.3 μg/g.dw. The most abundant sterol detected was β-sitosterol (STI) with average concentrations of 2.6 μg/g.dw, followed by cholesterol (CHOE), stigmasterol (STIG) and stigmastanol (STAN). The concentration of coprostanol (COP) was between 0.03 and 1.66 μg/g.dw. Through correlation analysis, it was found that there was a significant correlation between fecal sterols and plant sterols. So the plant sterols shall not be neglected in evaluating the sources of pollution for their impact to identify the fecal sources. The study suggests that the composition and distribution of sterols in surface sediment provide useful information for environmental contamination monitoring and assessment in the inland lake.

  11. Characteristics of biomarkers in the Recent sediment from Qinghai Lake, northwest China

    Pu, Fan; Yaorong, Qian; Baisheng, Zhang

    The occurrence of biomarker hydrocarbons in the Recent sediment of Qinghai Lake was investigated. It was found that the distribution of these biomarkers in Qinghai Lake, a semi-saline water lake, is unusual. The distribution of n-alkanes is predominated by high carbon-numbered alkanes with a high OEP (CPI) value. Two series of bicyclic sesquiterpanes derived from micro-organisms, e.g. algae or bacteria, were detected. The occurrence of tricyclic and tetracyclic terpenoids is characterized by the input of the organic matter from aquatic organisms. The conversion from hopenes existing in bacteria and blue-green algae into hopanes is put forward in this paper. C 27C 29 regular steranes, 4-methylsteroids, diasteranes, pregnanes, norsteroids and secosteranes were found in abundance in the sedimentary samples. Another important contribution of this paper is towards the geochemistry of amino acids in the Recent sediment of Qinghai Lake. The composition, distribution and evolution of the amino acids in the lacustrine sediments will be discussed in detail. It was found that several ratios of different amino acids have a clear diagenesis trend in the two cores studied. The racemization reaction of amino acids and their application in the geochemistry will also be discussed. The racemization of alanine and leucine were employed in this study to calculate the age of the sediment samples, with satisfactory result.

  12. Temporal variation of trace metal geochemistry in floodplain lake sediment subject to dynamic hydrological conditions

    Griethuysen, van C.; Luitwieler, M.; Joziasse, J.; Koelmans, A.A.


    Climate change and land use may significantly influence metal cycling in dynamic river systems. We studied temporal variation of sediment characteristics in a floodplain lake, including concentrations of dissolved organic carbon, acid volatile sulfide and trace metals. The sampling period included a

  13. Patterns of extracellular enzyme activities in littoral sediments of Lake Gooimeer, The Netherlands

    Boschker, H.T.S.; Cappenberg, T.E.


    The seasonal variation in enzymatic activities against protein and several polysaccharides together with esterase as a measure of general hydrolytic activity was studied in a transect of sediments through the littoral zone of Lake Gooimeer, The Netherlands. Absolute activities showed a linear

  14. Decomposition of organic matter in the littoral sediments of a lake

    Boschker, H.T.S.


    This thesis deals with the microbial decomposition of organic matter in littoral sediments of lakes. Special attention was given to the initial step in the decomposition of polysaccharides that form a major component of macrophyte litter produced in these systems. This initial step, an

  15. Bioaccumulation of persistent organic pollutants from floodplain lake sediments: linking models to measurement

    Moermond, C.T.A.


    The main research questions of this research were (1) what is the extent and nature of bioavailability of sediment-bound polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) and (2) what are the effects of lake ecosystem structure on fate and bioaccumulation of PCBs and PAHs. Fast-desorbi


    The research is to characterize concentrations of total methylmercury in waters and surficial sediments of Vermont and New Hampshire lakes, and to relate these data to commonly measured water column chemical parameters and watershed-level physical attributes. The primary goal of...

  17. Biogeochemical cycling of nutrients and trace metals in the sediment of Haringvliet lake: reponse to salinization

    Canavan, R.W.


    This thesis examines sediment redox processes associated with organic matter degradation and their impact on the cycling of nutrients (N, P) and trace metals (Cd, Co, Ni, Pb, Zn). Our study site, Haringvliet Lake, is located in the Rhine-Meuse River Delta in the southwest of The Netherlands. This wa

  18. Biogeochemical Cycling of Nutrients and Trace Metals in the Sediment of Haringvliet Lake: Response to Salinization

    Canavan, R.W.


    This thesis examines sediment redox processes associated with organic matter degradation and their impact on the cycling of nutrients (N, P) and trace metals (Cd, Co, Ni, Pb, Zn). Our study site, Haringvliet Lake, is located in the Rhine-Meuse River Delta in the southwest of The Netherlands. This wa

  19. Distribution and sources of n-alkanes in surface sediments of Taihu Lake, China

    Yu Yunlong


    Full Text Available The last study on n-alkanes in surface sediments of Taihu Lake was in 2000, only 13 surface sediment samples were analysed, in order to have a comprehensive and up-to-date understanding of n-alkanes in the surface sediments of Taihu Lake, 41 surface sediment samples were analyzed by GC-MS. C10 to C37 were detected, the total concentrations of n-alkanes ranged from 2109 ng g−1 to 9096 ng g−1 (dry weight. There was strong odd carbon predominance in long chain n-alkanes and even carbon predominance in short chain n-alkanes. When this finding was combined with the analysis results of wax n-alkanes (WaxCn, carbon preference index (CPI, unresolved complex mixture (UCM, hopanes and steranes, it was considered that the long chain n-alkanes were mainly from terrigenous higher plants, and that the short chain n-alkanes mainly originated from bacteria and algae in the lake, compared with previous studies, there were no obvious anthropogenic petrogenic inputs. Terrestrial and aquatic hydrocarbons ratio (TAR and C21−/C25+ indicated that terrigenous input was higher than aquatic sources and the nearshore n-alkanes were mainly from land-derived sources. Moreover, the distribution of short chain n-alkanes presented a relatively uniform pattern, while the long chain n-alkanes presented a trend that concentrations dropped from nearshore places to the middle of lake.

  20. Metal impacts on microbial biomass in the anoxic sediments of a contaminated lake

    Gough, Heidi L.; Dahl, Amy L.; Nolan, Melissa A.; Gaillard, Jean-Francois; Stahl, David A.


    Little is known about the long-term impacts of metal contamination on the microbiota of anoxic lake sediments. In this study, we examined microbial biomass and metals (arsenic, cadmium, chromium, copper, iron, lead, manganese, and zinc) in the sediments of Lake DePue, a backwater lake located near a former zinc smelter. Sediment core samples were examined using two independent measures for microbial biomass (total microscopic counts and total phospholipid-phosphate concentrations), and for various fractions of each metal (pore water extracts, sequential extractions, and total extracts of all studied metals and zinc speciation by X-ray absorption fine structure (XAFS). Zinc concentrations were up to 1000 times higher than reported for sediments in the adjacent Illinois River, and ranged from 21,400 mg/kg near the source to 1,680 mg/kg near the river. However, solid metal fractions were not well correlated with pore water concentrations, and were not good predictors of biomass concentrations. Instead, biomass, which varied among sites by as much as two-times, was inversely correlated with concentrations of pore water zinc and arsenic as established by multiple linear regression. Monitoring of other parameters known to naturally influence biomass in sediments (e.g., organic carbon concentrations, nitrogen concentrations, pH, sediment texture, and macrophytes) revealed no differences that could explain observed biomass trends. This study provides strong support for control of microbial abundance by pore water metal concentrations in contaminated freshwater sediments.

  1. Lake sediments record prehistoric lead pollution related to early copper production in North America.

    Pompeani, David P; Abbott, Mark B; Steinman, Byron A; Bain, Daniel J


    The mining and use of copper by prehistoric people on Michigan's Keweenaw Peninsula is one of the oldest examples of metalworking. We analyzed the concentration of lead, titanium, magnesium, iron, and organic matter in sediment cores recovered from three lakes located near mine pits to investigate the timing, location, and magnitude of ancient copper mining pollution. Lead concentrations were normalized to lithogenic metals and organic matter to account for processes that can influence natural (or background) lead delivery. Nearly simultaneous lead enrichments occurred at Lake Manganese and Copper Falls Lake ∼8000 and 7000 years before present (yr BP), indicating that copper extraction occurred concurrently in at least two locations on the peninsula. The poor temporal coherence among the lead enrichments from ∼6300 to 5000 yr BP at each lake suggests that the focus of copper mining and annealing shifted through time. In sediment younger than ∼5000 yr BP, lead concentrations remain at background levels at all three lakes, excluding historic lead increases starting ∼150 yr BP. Our work demonstrates that lead emissions associated with both the historic and Old Copper Complex tradition are detectable and can be used to determine the temporal and geographic pattern of metal pollution.

  2. Sediment core fossils in ancient Lake Ohrid: testing for faunal change since the Last Interglacial

    C. Albrecht


    Full Text Available Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harbouring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200 from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR dating of mollusc shells from the same stratigraphic level yielded an age of 130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic subdivision comprising the basal succession of core Co1200 between 181.5–263 cm, appeared solid, greyish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70% and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated and the agreement between sediment and palaeontological proxies was tested.

    The study also aims at investigating major faunal changes since the Last Interglacial and searching for signs of extinction events.

    The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m water depth mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid

  3. Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

    S. Audry


    Full Text Available This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC stock in thermokarst lake sediments of 14 ± 2 kg m−2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways was evidenced from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions. This shift was promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of

  4. Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

    Audry, S.; Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Dupré, B.


    This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m-2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development

  5. Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

    S. Audry


    Full Text Available This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC stock in thermokarst lake sediments of 14 ± 2 kg m−2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all

  6. Sediment plume response to surface melting and supraglacial lake drainages on the Greenland ice sheet

    Chu, Vena W.; Smith, Laurence C; Rennermalm, Asa K.


    of a downstream sediment plume in Kangerlussuaq Fjord by comparing: (1) plume area and suspended sediment concentration from Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and field data; (2) ice-sheet melt extent from Special Sensor Microwave/Imager (SSM/I) passive microwave data; and (3......) supraglacial lake drainage events from MODIS. Results confirm that the origin of the sediment plume is meltwater release from the ice sheet. Interannual variations in plume area reflect interannual variations in surface melting. Plumes appear almost immediately with seasonal surface-melt onset, provided...... the estuary is free of landfast sea ice. A seasonal hysteresis between melt extent and plume area suggests late-season exhaustion in sediment supply. Analysis of plume sensitivity to supraglacial events is less conclusive, with 69% of melt pulses and 38% of lake drainage events triggering an increase in plume...

  7. Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic: Levels, sources and fluxes

    Jiao Liping [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Zheng, Gene J. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong (China); Minh, Tu Binh; Richardson, Bruce [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Chen Liqi; Zhang Yuanhui [Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Yeung, Leo W.; Lam, James C.W. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Yan, Xulin [Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Lam, Paul K.S. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)], E-mail:; Wong, Ming H. [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong (China)], E-mail:


    Surface sediments from remote lakes and coastal areas from Ny-Alesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Alesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Alesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies. - High levels of PAHs and specific patterns of PBDEs were found in sediments from the remote Norwegian Arctic lakes.

  8. A late Holocene record of solar-forced atmospheric blocking variability over Northern Europe inferred from varved lake sediments of Lake Kuninkaisenlampi

    Saarni, Saija; Muschitiello, Francesco; Weege, Stefanie; Brauer, Achim; Saarinen, Timo


    This study presents a new varved lake sediment sequence from Lake Kuninkaisenlampi, Eastern Finland. The record is constituted by alternations of clastic and biogenic laminae and provides a precise chronology extending back to 3607 ± 94 varve yrs. BP. The seasonality of the boreal climatic zone, with cold winters and mild summers, is reflected in the varve structure as a succession of three laminae from bottom to top, (i) a coarse to fine-grained detrital lamina marked by detrital catchment material transported by spring floods; (ii) a biogenic lamina with diatoms, plant and insect remnants reflecting biological productivity during the season of lake productivity; and (iii) a very fine amorphous organic lamina deposited during the winter stratification. The thickness of the detrital lamina in the lake reflects changes in the rate of spring snow melt in the catchment and is, therefore, considered a proxy for winter conditions. Hence, the record allows reconstructing local climate and environmental conditions on inter-annual to the multi-centennial timescales. We find that minerogenic accumulation reflected in the detrital lamina exhibits a high multi-decadal to centennial-scale spectral coherency with proxies for solar activity, such as Δ14C, and Total Solar Irradiance, suggesting a strong link between solar variability and sediment transport to the lake basin. Increased catchment erosion is observed during periods of low solar activity, which we ascribe to the development of more frequent atmospheric winter blocking circulation induced by solar-forced changes in the stratosphere. We suggest that soil frost in the catchment of Lake Kuninkaisenlampi related to more frequent winter blocking led to increased surface run-off and ultimately to increased catchment erosion during spring. We conclude that, during the past ca 3600 years, solar forcing may have modulated multi-decadal to centennial variations in sedimentation regimes in lakes from Eastern Finland and

  9. Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake.

    Niu, Yong; Jiao, Wei; Yu, Hui; Niu, Yuan; Pang, Yong; Xu, Xiangyang; Guo, Xiaochun


    With regard to the size of China's freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL) at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM) at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake's central region, whereas the uniform distribution areas of those with lower concentrations were the lake's southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU), it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by the reduction of mean

  10. High-resolution past environmental reconstruction in East Asia using annually laminated lake sediments of Lake Megata in northeastern Japan

    Yamada, K.; Gotanda, K.; Yonenobu, H.; Shinozuka, Y.; Kitagawa, J.; Makohonienko, M.; Schwab, M.; Haraguchi, T.; Yasuda, Y.


    37 m-long non-glacial varved sequences were taken from Ichi-no-Megata maar in Oga Peninsula, Akita, northern part of Japan. Ichi-no-Megata maar occupies 0.25 km2 with a maximum water depth of ca. 45.1 m. The shape of lake is a kettle-type basin and the deepest bottom basin is very flat. We took core samples (named IMG06 core) at the center of the lake in November to December in 2006. In order to take completely continuous maar sediment, we drilled three holes and take every sample from each hole which apart only few meters. In this drilling campaign, we can 37 m-long continuous maar sediment except thick volcanic deposits from 26.5 to 31.7m in core. The sedimentological feature of IMG06 core is dominated by thin lamination clay/silt from most top part up to 37 m with turbidites characterized upward fining structure. The SEM image observation of lamination reveals that sponge-like lamina consists of diatom assemblage against dark colored lamina consists of mixture of detritus minerals, clay minerals, and diatom. It means sponge-like lamina deposits during spring season, and later one deposits during another three seasons, and then these thin lamination of IMG06 core could be identified as annual lamination (varves). This interpretation is supported by the correlation of historic event as earthquake and tunnel construction. In this IMG06 core, six volcanic ashes are found and we have also analyzed radiocarbon dating from 38 horizons of the core to use leaf and seeds inter-bedded varves. As the results, the IMG06 core covers from 25,000 to 4,000 14C yr BP with stable sedimentation rates (0.71mm/year).

  11. Sediment Budget on the Indiana Shore at Burns Harbor, Lake Michigan


    nourishment sediment evaluation for southern Lake Michigan, final report,” rep. prepared for Oceanographic Studies , Inc., Groton, CT by SAECO, Inc., West Lafayette, IN, 37 p. 146 20/03/2015 16 pp ...1. U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA...was 83,000 yd3/year. The total transport calculated in this study is higher than most published previous estimates. The volume of sediment now

  12. Nutrient exchange and release experiment and its simulation study in lake water-sediment interface

    XUE Lian-qing; HAO Zhen-chun


    The sediment distributed and insolated under lake was collected for experiments. The nutrient layer distribution conditions of sampled sediment and its physical and chemical characteristics were analyzed to simulate and assess the influence degree to lake water quality. Based on the dynamic water exchanging experiments the nutrient release process in sediment and influence mechanism to substance exchanging on water-sediment interface was studied, and the correlation between the changing content of total phosphors and total nitrogen in sediment and covered water were analyzed for setting up a simulation model. At the same time the influence degree is explained in detail. The experimental results indicated that even if clean water without nutrient contents was used for water exchangement so as to decrease pollution or prevent eutrophication, however owing to the vertical nutrient distribution in lake sediment, it will lead to the increasing release amount greatly especially when the organic nutrient contained in sediment turns into inorganic status because of isolation. Besides the release process of total phosphate (TP) and total nitrogen (TN) were modeled and each nutrient's exchanging equation at interface caused by covered water nutrient concentration changing was set up. According to the simulating prediction, TP and TN content of cover water will also sustain a steady higher level in a long period. The nutrient release amount of sediment is not only affected by the covered water concentration but also connects with accumulative time. The experiments provide the fundamental theoretical and practical basis for taking ecological restoration project. And research is helpful to prevent or restore lake eutrophication.

  13. Sedimentary processes in High Arctic lakes (Cape Bounty, Melville Island, Canada): What do sediments really record?

    Normandeau, Alexandre; Lamoureux, Scott; Lajeunesse, Patrick; Francus, Pierre


    Lacustrine sedimentary sequences can hold a substantial amount of information regarding paleoenvironments, hydroclimate variability and extreme events, providing critical insights into past climate change. The study of lacustrine sediments is often limited to the analysis of sediment cores from which past changes are inferred. However, studies have provided evidence that the accumulation of sediments in lacustrine basins and their distribution can be affected by a wide range of internal and external forcing mechanisms. It is therefore crucial to have a good knowledge of the factors controlling the transport and distribution of sediments in lakes prior to investigating paleoenvironmental archives. To address this knowledge gap, the Cape Bounty Arctic Watershed Observatory (CBAWO), located on southern Melville Island in the Canadian High Arctic, was initiated in 2003 as a long term monitoring site with the aim of understanding the controls over sediment transport within similar paired watersheds and lakes. The East and West lakes have been monitored each year since 2003 to document the role of hydro-climate variability on water column processes and sediment deposition. Moorings recording water electrical conductivity, temperature, density, dissolved oxygen and turbidity, as well as sediment traps were deployed during the active hydrological period (generally May-July). These data were analyzed in combination with hydrological and climatic data from the watersheds. Additionally, a high-resolution bathymetric and sub-bottom survey was completed in 2015 and allowed imaging the lake floor and sub-surface in great detail. This combination of process and lake morphological data are unique in the Arctic. The morphostratigraphic analysis reveals two highly disturbed lake floors, being widely affected by subaqueous mass movements that were triggered during the last 2000 years. Backscatter intensity maps and the presence of bedforms on each delta foresets indicate that

  14. [GIS Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments of Shallow Lakes in Jiangsu Province].

    Li, Ying-jie; Zhang, Lie-yu; Wu, Yi-wen; Li, Cao-le; Yang, Tian-xue; Tang, Jun


    To understand pollution of heavy metals in surface sediments of shallow lakes, surface sediments samples of 11 lakes in Jiangsu province were collected to determine the content of six heavy metals including As, Cr, Cu, Pb, Zn and Ni. GIS was used to analyze the spatial distribution of heavy metals, and geological accumulation index (Igeo), modified contamination index (mCd) pollution load index (PLI) and potential ecological risk index (RI) were used to evaluate heavy metal contamination in the sediments. The results showed that: in the lakes' surface sediments, the average content of As, Cu, Zn, Cr, Pb, Ni in multiples of soil background of Jiangsu province were 1.74-3.85, 0.65-2.66, 0.48-3.56, 0.43-1.52, 0.02-1.49 and 0.12-1.42. According to the evaluation results of Igeo and RI, As, which had high degree of enrichment and great potential ecological risk, was the main pollutant, followed by Cu, and pollution of the rest of heavy metals was relatively light. Combining the results of several evaluation methods, in surface sediments of Sanjiu Lake, Gaoyou Lake and Shaobo Lake, these heavy metals had the most serious pollution, the maximum pollution loading and moderate potential ecological risk; in surface sediments of Gehu Lake, Baima Lake and Hongze Lake, some regions were polluted by certain metals, the overall trend of pollution was aggravating, the pollution loading was large, and the potential ecological risk reached moderate; in the other 5 lakes, the risk of sediments polluted by heavy metals, as well as the pollution loading, was small, and the overall was not polluted.

  15. Temporal Variation in the Stable Isotopic Composition of Water and Sediment in Seneca Lake, NY (USA): Implications for Paleoclimate Reconstructions

    Curtin, T.; Finkelstein, D. B.; Gunn, P.


    Paleoclimatic studies often use stratigraphic changes in the oxygen isotope composition (δ18O) of lacustrine carbonate to infer changes in water temperature and/or the δ18O of lake water. To better understand the environmental factors that influence the isotopic composition of lacustrine carbonates and the assumptions that need to be made to infer past changes in climate, we undertook a four-year study of the water chemistry and sediment trap material in Seneca Lake (NY, USA), a large, monomictic, glacial, hardwater lake. Sediment trap material collected weekly between May 2009 and 2013 together with isotopic monitoring of surface and bottom water allow for analysis of the controls on calcite precipitation in the lake. We show that calcite mainly accumulates in traps July through September when the lake water column is stratified and epilimnetic water temperature exceeds 20°C. Up to ~70% of the sediment is comprised of calcite during summer and only ~10% of the sediment is calcite during autumn, winter, and spring. The δ18O of Seneca Lake epilimnetic water varies by only ~0.6 ‰ throughout the year whereas the δ18O of bulk carbonate varies by as much as 2.4‰. As calcite precipitates in the eplimnion, the δ18O declines. Likely due to the large volume and residence time of water, the δ18O of Seneca Lake water appears to track changes in temperature. Our temperature reconstruction using the δ18O of calcite and epilimnetic lake water reveals that calcite was a reasonable proxy for lake surface temperature from July through September. During the remainder of the year, reconstructed temperatures exceed actual temperatures by as much as 18°C. Sediment resuspension (including calcite) during isothermal conditions may explain why calcite is a poor predictor of lake surface temperature in late autumn though spring. The δ18O of calcite in this lake records summer temperatures rather than year-round conditions.

  16. Sediments as tracers for transport and deposition processes in peri-alpine lakes: A case study

    Righetti, Maurizio; Toffolon, Marco; Lucarelli, Corrado; Serafini, Michele


    SummaryThe benthic sediment fingerprint is analysed in the small peri-alpine lake Levico (Trentino, Italy) to identify the causes of recurrent phenomena of turbidity peaks, particularly evident in a littoral region of the water body. In order to study the sediment transport processes, we exploit the fact that the sediment supply from the major tributary has a specific chemical composition, which differs from that of the nearby lake basin. Three elements (Fe, Al, K) have been used as tracers to identify the source and the deposition patterns of tributary sediments, and another typical element, Si, has been critically analysed because of its dual (allochthonous and autochthonous) origin. Several samples of the benthic material have been analysed using SEM-EDS, and the results of the sedimentological characterisation have been compared with the patterns of sediment accumulation at the bed of the lake obtained using a three-dimensional numerical model, in response to the tributary supply under different external forcing and stratification conditions. The coupled use of field measurements and numerical results suggests that the turbidity phenomena are strongly related to the deposition of the sediments supplied by the tributary stream, and shows that it is possible to reconstruct the process of local transport when the tributary inflow is chemically specific.

  17. [Evaluating comprehensive quality of sediment in Dianchi Lake using adjusted AHP method and 137Cs dating].

    Zhang, Yan; Deng, Xi-Hai; Peng, Bu-Zhuo


    It is difficult to evaluate comprehensive quality of sediment and to understand development trend of pollution because of absence of monitoring data, especially history data. Combining the method of 137Cs dating with the ways of general sampling and measurement can easily resolve the problem of absence of data and also provide the possibility for calculating weighted environmental quality comprehensive index using the adjusted analytical hierarchy process (AHP) method. In order to overcome the willfulness the judgment matrix is formed objectively based on calculating monitoring data. Based on the monitoring data of sediment pollution and the weights of various factors gained by adjusted AHP method the comprehensive quality of sediment in each zone of Dianchi Lake was evaluated and the results indicated that the pollution of sediments in each zone at the present be serious more than that in the history. The condition may be related to the industrial development and distribution of industries in Dianchi Lake basin. Therefore, in order to improve the comprehensive quality of sediment in Dianchi Lake and to prevent the secondary pollution of heavy metals in sediment from happening, it is necessary to control the pollutants discharge and to remove the pollutants with various ways.

  18. Remobilization of trace metals induced by microbiological activities near sediment-water interface, Aha Lake, Guiyang

    WANG Fushun; LIU Congqiang; LIANG Xiaobing; WEI Zhongqing


    The Aha Lake, as a seasonally oxygen-absent man-made reservoir, has been polluted by acidic mining drainage and domestic sewages for a long time, withiron, manganese and sulfate excessively enriched in water and sediment. By means of microbe counting, the analysis of trace metals in pore water and electronicacceptors for organic matter decomposing, we have found that strong biogeochemical remobilization of trace metals occurred near the water-sediment interface. The microbial reduction of iron, manganese and sulfate took place in different parts throughout the sediment core with the extend of iron reduction lower than that of sulfate reduction, which happened in the surficial sediments and hampered the upward release of some trace metals to some extent. Some trace metals in pore water, due to the "dual releasing" effects caused by the reduction of Fe3+ andMn4+ at varying depth, show a tendency of being enriched excessively in the upper 10 cm of sediment. In this study, we discussed the microbiological mechanism of trace metals enrichment in surficial sediments and the environmental condition, with an attempt to realize the unsteady mobilization of trace metals and their potential harm to overlying lake water in the Aha Lake, Guiyang.

  19. Distribution and Pollution Assessment of Trace Metals in Core Sediments from the Artificial Lake Shihwa, Korea

    Kongtae Ra


    Full Text Available Metal concentrations in creek water, sewer outlets and core sediments were analyzed to identify the potential origin of metal pollution and to evaluate the extent of metal pollution and potential toxicity of Lake Shihwa. Mean concentrations for dissolved metals in creek water and sewer outlets were 1.6~136 times higher than those in the surface seawater of Lake Shihwa. Metal concentrations in creek water from an industrial region were also higher than those from municipal and agricultural regions, indicating that the potential source of metal pollution in the study area might be mainly due to industrial activities. The vertical profiles of metals in core sediments showed an increasing trend toward the upper sediments. Extremely higher concentrations of metals were observed in the vicinity of Banweol industrial complex. The results of a geo-accumulation index indicated that Cu, Zn and Cd were highly polluted. By comparing the sediment quality guidelines such as TEL and PEL, six metals such as Cr, Ni, Cu, Zn, Cd and Pb levels in core sediments nearby industrial complex exceeded the PEL value. Mean PEL quotient (mPELQ was used to integrate the estimate of potential toxicity for measured metals in the present study. Mean PELQs in core sediments from Lake Shihwa ranged from 0.2~2.3, indicating that benthic organisms nearby the industrial complex may have been adversely affected.

  20. Historical variations in lead fluxes in the Pyrenees (northeast Spain) from a dated lake sediment core

    Camarero, L.; Masque, P.; Devos, W.; Ani-Ragolta, I.; Catalan, J.; Moor, H.C.; Pla, S.; Sanchez-Cabeza, J.A. [University of Barcelona, Barcelona (Spain). Dept. of Ecology


    Variations in Pb concentration in lake sediments reflect changes in the fluxes of this element in the past. A sediment core from a lake in the Pyrenes (Lake Redo at 2,240 m a.s.l., NE Spain) was studied, with the aim of reconstructing past environmental and climatic conditions in the lake and its catchment area. The core was dated using both {sup 210}Pb and {sup 14}C. A surface peak of Pb concentration, which was about 10 times higher than the background level, was found. This peak is attributed to mining activities since the beginning of this century. Although Pb pollution due to the combustion of gasoline is expected to be present, no evidence can be deduced from Pb isotope ratios of sediment due to the masking effect of Pb from mines. A second peak appeared in a deeper layer, with a maximum Pb concentration of about 17 times higher than the background level. The origin of this peak is unclear. All evidence suggests that the ancient peak is due to mining operations in the central Pyrenees area, which were not documented historically. 24 refs., 3 figs., 3 tabs.

  1. Generating quantitative palaeoflood data from homogeneous lake sediments: a case-study from Brotherswater, northwest England

    Schillereff, Daniel; Chiverrell, Richard; Macdonald, Neil; Hooke, Janet


    The scarcity of long-term hydrological data is a barrier to reliably determining the likelihood of floods becoming more frequent and/or intense in a warmer world. Lakes and their sediments are increasingly being used to reconstruct long-term, highly-resolved datasets of past floods but the ultimate goal, generating quantitative palaeohydrological data to augment flood frequency analyses, is a persistent challenge. To this end, ascertaining the autogenic and allogenic processes influencing the character and preservation potential of palaeoflood laminations and determining the minimum discharge at which a sedimentary imprint will be deposited in a particular system are two key precursors. Some success has been achieved at lakes containing annually-laminated sequences or where event layers exhibit well-defined lithological contacts. Many non-alpine and non-polar lakes, especially those in temperate regions, are instead characterised by visually-homogeneous, organic-rich sediments from which discrete flood laminations are difficult to discriminate. Working at Brotherswater, a small upland lake in northwest England, we have successfully demonstrated an approach to obtain flood frequency and magnitude data from this type of lake system by integrating a 16 month sediment trap deployment (CE 2013-2014) with the recent (CE 1962 - 2014) depositional record. The geochemical composition and end-member modelling of the trap data shed light on the seasonal variation in background sedimentation dynamics, specifically enhanced sediment supply during winter, spring diatom blooms and heightened summer productivity, which alter the signature of coarse-grained deposition in response to higher flows. Having pinpointed the characteristic flood end-member, comparison of the short-core palaeoflood reconstruction to local river discharge data was able to reveal the hydrological thresholds of this system: flood magnitudes calculated to have a four year recurrence interval are preserved in

  2. Stratigraphy and Chronology of the Lake Sediments from Crimea as a Basis for Reconstructing the Black Sea Level Fluctuations

    Stolba, Vladimir; Subetto, D.A.; Kuznetsov, D.D.


    Two long sediment sequences have been recovered from two lakes in Western Crimea (Lakes Saki and Dzharylgach) within a frame of the joint Danish-Russian-Ukrainian interdisciplinary project "Northern Black Sea in the 1st millennium BC: Human history and climate changes". A detailed examination...

  3. Organic carbon mass accumulation rate regulates the flux of reduced substances from the sediments of deep lakes

    Steinsberger, Thomas; Schmid, Martin; Wüest, Alfred; Schwefel, Robert; Wehrli, Bernhard; Müller, Beat


    The flux of reduced substances, such as methane and ammonium, from the sediment to the bottom water (Fred) is one of the major factors contributing to the consumption of oxygen in the hypolimnia of lakes and thus crucial for lake oxygen management. This study presents fluxes based on sediment porewater measurements from different water depths of five deep lakes of differing trophic states. In meso- to eutrophic lakes Fred was directly proportional to the total organic carbon mass accumulation rate (TOC-MAR) of the sediments. TOC-MAR and thus Fred in eutrophic lakes decreased systematically with increasing mean hypolimnion depth (zH), suggesting that high oxygen concentrations in the deep waters of lakes were essential for the extent of organic matter mineralization leaving a smaller fraction for anaerobic degradation and thus formation of reduced compounds. Consequently, Fred was low in the 310 m deep meso-eutrophic Lake Geneva, with high O2 concentrations in the hypolimnion. By contrast, seasonal anoxic conditions enhanced Fred in the deep basin of oligotrophic Lake Aegeri. As TOC-MAR and zH are based on more readily available data, these relationships allow estimating the areal O2 consumption rate by reduced compounds from the sediments where no direct flux measurements are available.

  4. Sediment dynamics in paired High Arctic lakes revealed from high-resolution swath bathymetry and acoustic stratigraphy surveys

    Normandeau, A.; Lamoureux, S. F.; Lajeunesse, P.; Francus, P.


    High Arctic lakes are commonly used for paleoclimatic reconstructions because they are particularly sensitive to climate variability. However, the processes leading to sediment deposition and distribution in these lakes are often poorly understood. Here for the first time in the Canadian High Arctic, we present original data resulting from swath bathymetry and subbottom surveys carried out on two lakes at Cape Bounty, Melville Island. The results reveal the dynamic nature of the lakes, in which mass movement deposits and bedforms on the deltas reflect frequent slope instabilities and hyperpycnal flow activity. The analysis of the mass movement deposits reveals that small blocky debris flows/avalanches, debris flows, and a slide occurred during the Holocene. These mass movements are believed to have been triggered by earthquakes and potentially by permafrost thawing along the shoreline. Altogether, these mass movement deposits cover more than 30% of the lake floors. Additionally, the river deltas on both lakes were mapped and reveal the presence of several gullies and bedforms. The presence of gullies along the delta front indicates that hyperpycnal flows generated at the river mouth can transport sediment in different trajectories downslope, resulting in a different sediment accumulation pattern and record. The dynamic nature of these two lakes suggests that further analysis on sediment transport and distribution within Arctic lakes is required in order to improve paleoclimatic reconstructions.

  5. Chemical quality of water, sediment, and fish in Mountain Creek Lake, Dallas, Texas, 1994-97

    Van Metre, Peter C.; Jones, S.A.; Moring, J. Bruce; Mahler, B.J.; Wilson, Jennifer T.


    The occurrence, trends, and sources of numerous inorganic and organic contaminants were evaluated in Mountain Creek Lake, a reservoir in Dallas, Texas. The study, done in cooperation with the Southern Division Naval Facilities Engineering Command, was prompted by the Navy?s concern for potential off-site migration of contaminants from two facilities on the shore of Mountain Creek Lake, the Naval Air Station Dallas and the Naval Weapons Industrial Reserve Plant. Sampling of stormwater (including suspended sediment), lake water, bottom sediment (including streambed sediment), and fish was primarily in Mountain Creek Lake but also was in stormwater outfalls from the Navy facilities, nearby urban streams, and small streams draining the Air Station. Volatile organic compounds, predominantly solvents from the Reserve Plant and fuel-related compounds from the Air Station, were detected in stormwater from both Navy facilities. Fuel-related compounds also were detected in Mountain Creek Lake at two locations, one near the Air Station inlet where stormwater from a part of the Air Station enters the lake and one at the center of the lake. Concentrations of volatile organic compounds at the two lake sites were small, all less than 5 micrograms per liter. Elevated concentrations of cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc, from 2 to 4 times concentrations at background sites and urban reference sites, were detected in surficial bottom sediments in Cottonwood Bay, near stormwater outfalls from the Reserve Plant. Elevated concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls, compared to background and urban reference sites, were detected in surficial sediments in Cottonwood Bay. Elevated concentrations of polycyclic aromatic hydrocarbons, indicative of urban sources, also were detected in Cottonwood Creek, which drains an urbanized area apart from the Navy facilities. Elevated concentrations of polychlorinated biphenyls were

  6. The effect of mayfly (Hexagenia spp.) burrowing activity on sediment oxygen demand in western Lake Erie

    Edwards, William J.; Soster, Frederick M.; Matisoff, Gerald; Schloesser, Donald W.


    Previous studies support the hypothesis that large numbers of infaunal burrow-irrigating organisms in the western basin of Lake Erie may increase significantly the sediment oxygen demand, thus enhancing the rate of hypolimnetic oxygen depletion. We conducted laboratory experiments to quantify burrow oxygen dynamics and increased oxygen demand resulting from burrow irrigation using two different year classes of Hexagenia spp. nymphs from western Lake Erie during summer, 2006. Using oxygen microelectrodes and hot film anemometry, we simultaneously determined oxygen concentrations and burrow water flow velocities. Burrow oxygen depletion rates ranged from 21.7 mg/nymph/mo for 15 mm nymphs at 23 °C to 240.7 mg/nymph/mo for 23 mm nymphs at 13 °C. Sealed microcosm experiments demonstrated that mayflies increase the rate of oxygen depletion by 2-5 times that of controls, depending on size of nymph and water temperature, with colder waters having greater impact. At natural population densities, nymph pumping activity increased total sediment oxygen demand 0.3-2.5 times compared to sediments with no mayflies and accounted for 22-71% of the total sediment oxygen demand. Extrapolating laboratory results to the natural system suggest that Hexagenia spp. populations may exert a significant control on oxygen depletion during intermittent stratification. This finding may help explain some of the fluctuations in Hexagenia spp. population densities in western Lake Erie and suggests that mayflies, by causing their own population collapse irrespective of other environmental conditions, may need longer term averages when used as a bio-indicator of the success of pollution-abatement programs in western Lake Erie and possibly throughout the Great Lakes.

  7. Coastal lake sediments reveal 5500 years of tsunami history in south central Chile

    Kempf, Philipp; Moernaut, Jasper; Van Daele, Maarten; Vandoorne, Willem; Pino, Mario; Urrutia, Roberto; De Batist, Marc


    We present an exceptionally long and continuous coastal lacustrine record of ∼5500 years from Lake Huelde on the west coast of Chiloé Island in south central Chile. The study area is located within the rupture zone of the giant 1960 CE Great Chilean Earthquake (MW 9.5). The subsequent earthquake-induced tsunami inundated Lake Huelde and deposited mud rip-up clasts, massive sand and a mud cap in the lake. Long sediment cores from 8 core sites within Lake Huelde reveal 16 additional sandy layers in the 5500 year long record. The sandy layers share sedimentological similarities with the deposit of the 1960 CE tsunami and other coastal lake tsunami deposits elsewhere. On the basis of general and site-specific criteria we interpret the sandy layers as tsunami deposits. Age-control is provided by four different methods, 1) 210Pb-dating, 2) the identification of the 137Cs-peak, 3) an infrared stimulated luminescence (IRSL) date and 4) 22 radiocarbon dates. The ages of each tsunami deposit are modelled using the Bayesian statistic tools of OxCal and Bacon. The record from Lake Huelde matches the 8 regionally known tsunami deposits from documented history and geological evidence from the last ∼2000 years without over- or underrepresentation. We extend the existing tsunami history by 9 tsunami deposits. We discuss the advantages and disadvantages of various sedimentary environments for tsunami deposition and preservation, e.g. we find that Lake Huelde is 2-3 times less sensitive to relative sea-level change in comparison to coastal marshes in the same region.

  8. Mineralization of organic carbon on and in the sediment of Lake Grevelingen

    Lindeboom, H. J.; De Klerk, H. A. J.; Sandee, A. J. J.

    Within the framework of a research project on the carbon cycle in saline Lake Grevelingen a study of the mineralization on and in the sediment was made. The oxygen uptake by the sediment was measured using the bell jar method at 6 sampling stations. Applying a C over O 2 conversion factor of 0.29, it was calculated that 330 g·m -2 is mineralized in the sediment of the lake annually. By means of biomass estimates of the macroflora and fauna inside the bell jars and regression analysis, the contribution of these organisms to the carbon mineralization rate was calculated to be 70 and 95 g·m -2·a -1, respectively. The effect of oxygen gradients and apparent diffusion coefficients upon the oxygen uptake rate was studied with microelectrodes. This indicated that bioturbation is a major factor influencing the oxygen uptake rate. A good correlation between this rate and temperature was found.

  9. Use of 87Sr/86Sr and δ11B to Identify Slag-Affected Sediment in Southern Lake Michigan

    Bayless, E. Randall; Bullen, Thomas D.; Fitzpatrick, John A.


    Slag is a ubiquitous byproduct of the iron-smelting industry and influences geochemistry and water quality in adjacent geologic units, ground and surface water. Despite extensive slag deposition along the Indiana shoreline of Lake Michigan, definitive evidence that slag has affected lakebed sediments has not been established. Concerns for the protection of water and ecosystem resources in the Great Lakes motivated this study to determine if strontium and boron isotopes could be used to identify and delineate slag-affected bed sediment in Lake Michigan. Sixty-five samples of bed sediment were acquired from the southern lobe of Lake Michigan and analyzed for 87Sr/86Sr and ??11B. Samples immediately offshore from Indiana steel mills and slag-disposal sites contained higher median 87Sr/86Sr values (0.70881) than shoreline sediments collected elsewhere in the basin (0.70847) and uniquely decreased with increasing distance from the shoreline. The highest ??11B values occurred in sediments from the Indiana shoreline (+12.9 to 16.4???) but were also elevated in sediments collected offshore from three Lake Michigan cities (+11.7 to 12.7???). Contoured isotope data indicated that 82-154 km2 of bed sediment along the Indiana shoreline had elevated 87Sr/86Sr and ??11B values relative to shoreline sediments elsewhere in southern Lake Michigan.

  10. Holocene paleoclimatic evidence and sedimentation rates from a core in southwestern Lake Michigan

    Colman, Steven M.; Jones, Glenn A.; Forester, R.M.; Foster, D.S.


    Preliminary results of a multidisciplinary study of cores in southwestern Lake Michigan suggest that the materials in these cores can be interpreted in terms of both isostatically and climatically induced changes in lake level. Ostracodes and mollusks are well preserved in the Holocene sediments, and they provide paleolimnologic and paleoclimatic data, as well as biogenic carbonate for stable-isotope studies and radiocarbon dating. Pollen and diatom preservation in the cores is poor, which prevents comparison with regional vegetation records. New accelerator-mass spectrometer 14C ages, from both carbon and carbonate fractions, provide basin-wide correlations and appear to resolve the longstanding problem of anomalously old ages that result from detrital organic matter in Great Lakes sediments. Several cores contain a distinct unconformity associated with the abrupt fall in lake level that occurred about 10.3 ka when the isostatically depressed North Bay outlet was uncovered by the retreating Laurentide Ice Sheet. Below the unconformity, ostracode assemblages imply deep, cold water with very low total dissolved solids (TDS), and bivalves have ?? 18O (PDB) values as light as - 10 per mil. Samples from just above the unconformity contain littoral to sublittoral ostracode species that imply warmer, higher-TDS (though still dilute) water than that inferred below the unconformity. Above this zone, another interval with ?? 18O values more negative than - 10 occurs. The isotopic data suggest that two influxes of cold, isotopically light meltwater from Laurentide ice entered the lake, one shortly before 10.3 ka and the other about 9 ka. These influxes were separated by a period during which the lake was warmer, shallower, but still very low in dissolved solids. One or both of the meltwater influxes may be related to discharge from Lake Agassiz into the Great Lakes. Sedimentation rates appear to have been constant from about 10 ka to 5 ka. Bivalve shells formed between about

  11. Historical changes in the concentrations of polycyclic aromatic hydrocarbons (PAHs) in Lake Peipsi sediments.

    Punning, Jaan-Mati; Terasmaa, Jaanus; Vaasma, Tiit; Kapanen, Galina


    The distribution of 11 individual polycyclic aromatic hydrocarbons (PAHs) was analysed in a (210)Pb dated sediment core from the deepest area of Lake Peipsi and in four surface sediment samples taken from littoral areas. According to the concentrations in the core three groups of PAHs may be distinguished: (1) relatively stable concentrations of PAHs within the whole studied time interval; (2) very low concentrations in sediments accumulated before intensive anthropogenic impact (from 19th century up to the 1920s) following a slight increase and (3) an overall increase in PAH concentrations since the 1920s up to the present. Comprehensive analysis of PAHs in the core and monitoring data obtained in the 1980s together with the lithology of sediments show that an increase of anthropogenically induced PAHs correlates well with the history of fuel consumption in Estonia and speaks about atmospheric long-distance transport of PAHs. The continuous increase of PAH concentrations since the 1920s do not support the earlier hypothesis about the dominating impact of the oil shale fired power plants near the lake, because their emissions decreased significantly in the 1990s. The concentration of PAHs in the deep lake core sample correlates well with the content of organic matter, indicating absorption and co-precipitation with plankton in the sediment.

  12. Geochemistry of iron,sulfur and related heavy metals in metal-polluted Taihu Lake sediments

    YIN Hong-Bin; FAN Cheng-Xin; DING Shi-Ming; ZHANG Lu; ZHONG Ji-Cheng


    To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake,two sites,in Meiliang Bay (ML) and Wuli Lake (WL),were selected to study the fractionation of iron,sulfur and related heavy metals.There were relatively high concentrations of Fe2+ and low concentrations of total S2- in porewaters,indicating that conditions in these sediments favored iron reduction.The concentrations of acid volatile sulfides in sediments were 1.9-9.6μmol g-1 at ML and 1.0-11.7 μmol g-1 at WL,both in the range of values detected in unpolluted lakes.Pyrite-S was 10.2-49.4 μmol g-1 at ML and 10.333.0 μmol g-1 at WL,accounting for more than 69% of the reduced inorganic sulfur at both sites.The low degree of sulphidization (<14%) and pyritization (<10%) indicate that sulfate may be the limiting factor for pyrite formation.The extractability of Mn,Cu,Pb,Zn,Ni,and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis.Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.

  13. Utilization of bathymetry data to examine lead sediment contamination distributions in Lake Ontario

    Chris H. Marvin


    Full Text Available Bathymetry data offer interesting opportunities for the analysis of contaminant distribution patterns. This research utilized lead surficial sediment sample data from Lake Ontario that were collected by the Canada Centre for Inland Waters in 1968 and 1998. Traditionally, two-dimensional analyses such as dot maps or proportional circle representation have been utilized to examine pollutant levels. Generating area estimates allows for expanded spatial analysis of contaminant distribution patterns. Lake-wide surfaces were derived using the ordinary kriging technique. These were then layered on bathymetry data to examine three-dimensional relationships between observed pollution patterns and lake-bottom features. Spatial variability was observed in both the 1968 and 1998 datasets. Contamination levels in 1998 dropped substantially, especially in areas that were previously the most heavily polluted and above the Probable Effect Level (4660.23 km2 or 26.72% of the common analysis area lake-bottom in 1998 versus 6189.07 km2 or 62.00% in 1968. Conversely, areas below the Threshold Effect Level increased from 922.09 km2 (5.29% in 1968 to 3484.22 km2 (19.98% in 1998. In both years, shallow and sill/ridge areas tended to have lower levels of contamination than deeper lake basins or contaminant inflow areas. The 1968 dataset likely provides a more detailed estimation surface as there were more points available for interpolation procedures. The kriging surfaces when combined with bathymetry, sedimentology information, and knowledge of physical processes provide a comprehensive illustration of the contaminant distributions whether they are high (1968 or when loadings are significantly reduced (1998. The results have implications for future sediment assessment programs and survey design on a lake-wide basis. The bathymetry data allowed for enhanced interpretation and an improved understanding of observed lead pollution patterns.

  14. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    Domaizon, I.; Savichtcheva, O.; Debroas, D.; Arnaud, F.; Villar, C.; Pignol, C.; Alric, B.; Perga, M. E.


    While picocyanobacteria (PC) are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes). In particular, we investigated the long-term (100 yr) diversity and dynamics of Synechococcus,, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided the ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction) results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria). The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and the following internally transcribed spacer (ITS). Up to 23 different OTUs (based on 16S rRNA), which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, the study of ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (in temperature and phosphorus concentration) affected Synechococcus, community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus, clusters. Providing such novel insights into the

  15. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    M. E. Perga


    Full Text Available While picocyanobacteria (PC are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes. We particularly investigated the long-term (100 yr diversity and dynamics of Synechococcus, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus (fraction of Synechococcus in total cyanobacteria. The diversity of Synechococcus in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and internal transcribed spacer (ITS. Up to 23 different OTUs (based on 16S rRNA, which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, study of the ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (here, in temperature and phosphorus concentration affected Synechococcus community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus clusters. Providing such novel insights into the long-term history of an important group of

  16. Missing-Presumed Eroded: Holocene Sedimentation Patterns in Seneca Lake, NY

    Loddengaard, K.; Curtin, T. M.


    The Finger Lakes of New York underwent a significant change in climate during the transition from the Hypsithermal to the Neoglacial at ~5 ka. To determine the effects of changes in climate on sedimentation patterns in the northern region of Seneca Lake, NY, we analyzed three cores that were collected along a shallow to deep water transect. Analyses of magnetic susceptibility, organic matter and carbonate content, fossil content, and grain size at a 1-cm interval were used to correlate cores, identify periods of erosion or non- deposition and assess the relative truncation of the Holocene sediment record. The stratigraphy and sedimentology of the cores indicate the lake contains a spatially and temporally discontinuous sediment record. Preliminary results indicate that the early to mid-Holocene sediment record was preferentially eroded in the deepwater cores, between 20 and 50 m water depth. At the deepwater sites, there is a gap in the sediment record that spans between ~12 and ~5 ka. Conversely, the late Holocene record is more complete in the deepwater cores than in the shallow water cores (12-20 m water depth). This data suggests a significant change on the controls and location of erosion and deposition in the lake during the Holocene. We hypothesize that the early to mid-Holocene sediment may have been eroded by strong internal seiches during stormy conditions that were initiated by cooler temperatures and a change in the position of the jet stream during the Hypsithermal-Neoglacial transition. Erosion occurred primarily in shallow water sites (<~30 m) during the Neoglacial, perhaps as a result of a change in the number and frequency of storms or strength of the internal seiche.

  17. Resilience and Restoration of Lakes

    Kathryn L. Cottingham


    Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

  18. Playa Lakes

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  19. Geochemical studies of backfill aggregates, lake sediment cores and the Hueco Bolson Aquifer

    Thapalia, Anita

    This dissertation comprises of three different researches that focuses on the application of geochemistry from aggregates, lake sediment cores and Hueco Bolson Aquifer. Each study is independent and presented in the publication format. The first chapter is already published and the second chapter is in revision phase. Overall, three studies measure the large scale (field) as well as bench scale (lab) water-rock interactions influenced by the climatic and anthropogenic factors spans from the field of environmental geology to civil engineering. The first chapter of this dissertation addresses the chemical evaluation of coarse aggregates from six different quarries in Texas. The goal of this work is to find out the best geochemical methods for assessing the corrosion potential of coarse aggregates prior to their use in mechanically stabilized earth walls. Electrochemical parameters help to define the corrosion potential of aggregates following two different leaching protocols. Testing the coarse and fine aggregates demonstrate the chemical difference due to size-related kinetic leaching effects. Field fines also show different chemistry than the bulk rock indicating the weathering impact on carbonate rocks. The second chapter investigates zinc (Zn) isotopic signatures from eight lake sediment cores collected both from pristine lakes and those impacted by urban anthropogenic contamination. Zinc from the natural weathering of rocks and anthropogenic atmospheric pollutants are transported to these lakes and the signatures are recorded in the sediments. Isotopic analysis of core samples provides the signature of anthropogenic contamination sources. Dated sediment core and isotopic analysis can identify Zn inputs that are correlated to the landuse and population change of the watersheds. Comparison of isotopic data from both pristine and urban lake sediment core also serves as an analog in other lake sediment cores in the world. The third chapter studies on Hueco Bolson

  20. Assessment of priority phenolic compounds in sediments from an extremely polluted coastal wetland (Lake Maryut, Egypt).

    Khairy, Mohammed A


    Although high concentrations of trace organic pollutants were recorded along the Egyptian Mediterranean Coast and its corresponding coastal wetlands, no published data are available for the levels of phenolic compounds. Thus, this work aimed to investigate the levels of phenolic compounds in sediments of a heavily polluted coastal wetland (Lake Maryut, Egypt). For that purpose, a method was optimized for the extraction and detection of chlorophenols, methylphenols, and nitrophenols in sediments using GC-MS. Sediments were extracted with 0.1 M NaOH/methanol by sonication. Cleanup of sediment extracts using liquid-liquid extraction and SPE was found important to remove most of the interfering co-extracts. The proposed analytical methodology was validated by analysis of matrix spikes. Detection limits were 0.063-0.694 μg/kg dw for sediments. Good recoveries (70-110%) and precision values (RSD Lake Maryut. Results revealed that higher concentrations were observed in the main basin (MB) of Lake Maryut affected by the discharge of effluents from a primary wastewater treatment plant, direct discharge of industrial effluents, domestic wastes, and agricultural effluents from Qalaa Drain (QD). Chlorophenols (CPs) were the major group detected in the lake sediments followed by methylphenols (MPs) and nitrophenols (NPs). CPs were dominated by 2-, 4-, and 3-chlorophenols. Concentrations of CPs were higher at the north and northwestern parts of the MB indicating the influence of industrial effluents discharged into the lake. On the other hand, higher concentrations of NPs were observed at the south and southwestern parts of the MB, which is subjected to the discharge of agricultural and domestic effluents via QD. Results of the risk assessment revealed that phenol, cresols, 2,4-dinitrophenol, 4-NP, 2-CP, 2,3,4,6-tetrachlorophenol and 2,4-dimethylphenol are contaminants of concern and that adverse ecological effects could possibly occur to benthic species from the exposure to

  1. Phosphorus geochemistry of recent sediments in the South Basin of Lake Winnipeg

    Mayer, T.; Simpson, S.L.; Thorleifson, L.H.; Lockhart, W.L.; Wilkinson, Philip M.


    Lake Winnipeg supports the largest commercial fishery on Canadian Prairies. It has been influenced by a variety of environmental forces and anthropogenic activities. To gain a better understanding of recent changes in nutrient status of the lake, it is important to reconstruct its previous history from sedimentary records. Lacustrine sediments are known to be an important sink of many dissolved and suspended substances, including phosphorus, hence, they provide a permanent historical record of changes occurring in the lake. These changes may be induced by natural factors or by anthropogenic activities in the watershed. Phosphorus profiles from dated sediment cores collected in 1999 and 1994 from the South Basin of Lake Winnipeg were investigated to determine phosphorus enrichment in recent sediments. To interpret the nutrient status and depositional conditions responsible for the trends in total phosphorus, three operationally defined forms of phosphorus (P) were determined: non-apatite inorganic P, apatite P, and organic P. Significant increases in sediment phosphorus concentrations were observed in the uppermost 20 cm of the cores and several anomalies were observed at depth. A doubling in total phosphorus relative to aluminum over the last fifty years is largely due to increases in the non-apatite inorganic fraction, suggesting that much of sedimentary phosphorus increase is attributable to changes in the nutrient status of the water column related to anthropogenic inputs. Organic phosphorus exhibits a subtle increase in the upper 20 cm of the gravity cores, likely due to increases in the primary productivity of the lake. Except for the slight increase in deeper sediments, apatite phosphorus, which is thought to be of detrital origin, remained fairly constant over the length of the cores. Anomalous spikes in phosphorus concentrations deeper in the cores, comprised mainly of the non-apatite inorganic phosphorus fraction, likely resulted from natural variation in

  2. Reconstructing Climate Change Since The Late Glacial At Amsterdamøya, NW Svalbard (80°N), Based On Lake Sediments From Lake Hakluytvatnet

    Gjerde, Marthe; Bakke, Jostein; D'Andrea, William J.; Balascio, Nicholas L.; Hormes, Anne; Bradley, Raymond S.


    Records of past climatic changes are sparse and poorly resolved in the Arctic due to obvious reasons such as lack of dateable organic material and logistical challenges. Here, we present a new time series from the island of Amsterdamøya, NW Svalbard (80°N), based on lake sediments from Lake Hakluytvatnet. Located at the northernmost branch of the North Atlantic Current, this high-Arctic site is ideally placed to infer changes in past atmospheric and oceanic circulation patterns recorded as changes in precipitation and temperature. Our novel data set provides a climatic reconstruction based on multi-proxy analyses on lake sediments from a non-glacial lake. We have combined one long piston core with a shorter gravity core to capture the entire sediment infill from the bottom of the basin to the most recently accumulated sediments on top. A robust chronology has been established for the cores through 28 AMS radiocarbon (14C) ages in combination with one lead (210Pb) profile of the most recent sediments, and this gives an unprecedented age control for a lake at this latitude as well as a precise sediment accumulation rate. The Hakluytvatnet cores are analysed for physical sediment properties as well as newer scanning instruments (e.g. XRF scanning, Scanning Electron Microscope, SEM, analyses) in order to produce a high-resolution reconstruction of the climate development for the study site. A separate alkenone study will produce a high-resolution temperature curve for the area. Soil samples from the surrounding catchment have also been subject to geochemical analyses in order to distinguish between the relative influences of different sediment sources on sediment accumulation in the lake. Geomorphological mapping has been carried out to combine interpretation of the catchment development with the lake sediment record interpretation. Numerical analyses (e.g. Principal Component Analysis, PCA) are applied on the results from the lake sediment and catchment samples in

  3. Distribution, sources and composition of antibiotics in sediment, overlying water and pore water from Taihu Lake, China

    Xu, Jian [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhang, Yuan, E-mail: [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Zhou, Changbo [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Guo, Changsheng; Wang, Dingming [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Du, Ping [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Luo, Yi [College of Environmental Sciences and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071 (China); Wan, Jun; Meng, Wei [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Laboratory of Riverine Ecological Conservation and Technology, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)


    The occurrence of 15 antibiotics classified as sulphonamides, fluoroquinolones, macrolides, tetracyclines and trimethoprim in sediment, overlying water, and pore water matrices in Taihu Lake, China was studied. The total concentrations were from 4.1 μg/kg to 731 μg/kg, from 127 ng/L to 1210 ng/L, and from 1.5 ng/L to 216 ng/L in sediment, overlying water and pore water, respectively. Antibiotics in different locations originated from various sources, depending on human, agricultural and aquacultural activities. Composition analysis indicated that human-derived and animal-derived drugs significantly contributed to the total contamination of antibiotics in the lake, indicating the high complexity of contamination sources in Taihu Lake Basin. The in situ sediment–pore water partitioning coefficients were generally greater than sediment–overlying water partitioning coefficients, suggesting continuous inputs into the lake water. This study shows that antibiotics are ubiquitous in all compartments in Taihu Lake, and their potential hazards to the aquatic ecosystem need further investigation. - Highlights: • Antibiotics are ubiquitous in sediment, overlying water and pore water in Taihu Lake. • Antibiotics in Taihu Lake originated from human and nonhuman activities. • Ksp is higher than Ksw, indicating the continuous antibiotics input to lake water.

  4. The influence of restoration measures on phosphorus internal loading from the sediments of a hypereutrophic lake.

    Kowalczewska-Madura, Katarzyna; Dondajewska, Renata; Gołdyn, Ryszard; Podsiadłowski, Stanisław


    Uzarzewskie Lake was a hypereutrophic, dimictic lake characterized by low water transparency, high chlorophyll-a concentration and intense phytoplankton blooms; thus, restoration treatment was started. A chemical treatment, based on phosphorus inactivation with small doses of iron sulphate, was undertaken in 2006-2007. Nitrate-rich groundwater flowing from seepage springs was directed into the lake hypolimnion to increase redox potential since 2008. Phosphorus internal loading was reduced by more than 80% as a result of restoration treatment. In the profundal zone, where P release from the bottom sediments prevailed throughout the year, it decreased from 13.02 mg P m(-2) day(-1) in 2010 to 2.81 mg P m(-2) day(-1) in 2015. Meanwhile, in the littoral zone, P accumulation in bottom sediments predominated; hence, the mean value of internal loading was increasing from 2.61 mg P m(-2) day(-1) in 2011 to 10.24 mg P m(-2) day(-1) in 2015. The annual P load from the bottom sediments in the profundal zone was much higher than from the littoral zone as a result of (i) a higher P release in most years and (ii) the greater area of this zone (82% of the lake's area). The fraction of residual phosphorus (Res-P) has the largest share, and in recent years, this has shown a tendency to decrease. The sum of bioavailable fractions was low (average 5.7%) showing a downward trend in recent years. Sustainable restoration of the lake resulted in a slow but steady decreasing trend in internal phosphorus loading.

  5. Polybrominated diphenyl ethers (PBDEs) in the surface sediments and suspended particulate matter (SPM) from Lake Chaohu, a large shallow Chinese lake.

    He, Wei; Qin, Ning; Kong, Xiangzhen; Liu, Wenxiu; He, Qishuang; Ouyang, Huiling; Wang, Qingmei; Yang, Bin; Yang, Chen; Jiang, Yujiao; Xu, Fuliu


    Suspended particulate matter (SPM) and surface sediment samples were collected from Lake Chaohu to investigate the residues, congener profile, and spatial distribution of polybrominated diphenyl ethers (PBDEs) in a large shadow lake in the middle of the Yangtze River Basin. The concentration of Σ13BDEs (defined as the sum of 13 target congeners excluding BDE 209) and the concentration of BDE 209 ranged from 236.7 to 1373.4 pg/g dry weight (dw) and from 4.2 to 691.2 pg/g dw in the surface sediments, respectively, which were 2-3 orders of magnitude smaller than those found in the SPM. The congener composition was dominated by BDE 47 (50.8%) and BDE 209 (21.3%) in the sediment, while the proportion of BDE 47 to Σ14BDEs in the SPM was slightly higher than that in the sediment. The concentration of Σ14BDEs in the sediment from the drinking water source (WR) area in the eastern part of the lake was very low, with a mean value of 514.8 pg/g, whereas the mean concentration was 102.4 ng/g in the SPM. A cluster analysis (CA) was conducted to further illustrate the dominance of each congener and the similarity of each sampling site. Many factors, including resuspension, photodecomposition, microbial oxidation, local discharge, and dredging, influenced the distribution in the sediment and SPM for the PBDE congeners as well as the spatial distribution of PBDEs. A formula for the PBDE concentrations in the surface sediment and SPM was constructed to understand the potential relationship between sediment and SPM concentrations. Although the formula did not accurately predict specific PBDE congener concentrations in the sediment, it remains a practical and useful way to assess the overall pollution of PBDE in sediment in Lake Chaohu, as it depends only on the concentrations of PBDEs in the SPM.

  6. High-resolution imaging of labile phosphorus and its relationship with iron redox state in lake sediments

    Gao, Yulu; Liang, Tao; Tian, Shuhan;


    in freshwater lakes. In this study, two in-situ high-resolution diffusive gradients in thin films (DGT) techniques, Zr-Oxide DGT and ZrO-Chelex DGT, were used to investigate the release characteristics of P from sediments in a large freshwater lake (Dongting Lake, China; area of 2691 km(2)) experiencing...... a regional summer algal bloom. Two-dimensional distributions of labile P in sediments were imaged with the Zr-Oxide DGT without destruction of the original structure of the sediment layer at four sites of the lake. The concentration of DGT-labile P in the sediments, ranging from 0.007 to 0.206 mg L(-1...

  7. A report on the trace element concentrations in sediments, vegetation, and fishes from the Lake Thompson Wetland Complex, South Dakota

    US Fish and Wildlife Service, Department of the Interior — The results of this study identify the contaminants present, if any, and their concentrations in fish, cattail roots, and sediments from areas of concern in the Lake...

  8. Antarctic subglacial lakes drain through sediment-floored canals: theory and model testing on real and idealized domains

    Carter, Sasha P.; Fricker, Helen A.; Siegfried, Matthew R.


    Over the past decade, satellite observations of ice surface height have revealed that active subglacial lake systems are widespread under the Antarctic Ice Sheet, including the ice streams. For some of these systems, additional observations of ice-stream motion have shown that lake activity can affect ice-stream dynamics. Despite all this new information, we still have insufficient understanding of the lake-drainage process to incorporate it into ice-sheet models. Process models for drainage of ice-dammed lakes based on conventional R-channels incised into the base of the ice through melting are unable to reproduce the timing and magnitude of drainage from Antarctic subglacial lakes estimated from satellite altimetry given the low hydraulic gradients along which such lakes drain. We have developed an alternative process model, in which channels are mechanically eroded into the underlying deformable subglacial sediment. When applied to the known active lakes of the Whillans-Mercer ice-stream system, the model successfully reproduced both the inferred magnitudes and recurrence intervals of lake-volume changes, derived from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data for the period 2003-2009. Water pressures in our model changed as the flood evolved: during drainage, water pressures initially increased as water flowed out of the lake primarily via a distributed system, then decreased as the channelized system grew, establishing a pressure gradient that drew water away from the distributed system. This evolution of the drainage system can result in the observed internal variability of ice flow over time. If we are correct that active subglacial lakes drain through canals in the sediment, this mechanism also implies that active lakes are typically located in regions underlain by thick subglacial sediment, which may explain why they are not readily observed using radio-echo-sounding techniques.

  9. Paleoclimatic Change Inferred from Carbon Isotope Composition of Organic Matter in Sediments of Dabusu Lake, Jilin Province, China

    SHEN Ji(沈吉); ZHANG Enlou(张恩楼); YANG Xiangdong(羊向东); Ryo Matsumoto


    Study on the organic compounds and stable isotope composition of a sediment section in Dabusu Lake revealed that the organic materials in the sediments came mainly from terrestrial plants brought into the lake by runoff. The δ13C of the organic materials had high values during warm-dry climatic stages and decreased in cold-wet stages. Analysis of data on carbonate content and 14 C age showed that the lake basin had experienced several wet-cold and warm-dry climatic cycles since 15000 a BP. Since 6700 a BP, the climate reached a relatively stable warm-dry stage, so that the lake water was gradually condensed and finally a saline lake was formed.

  10. Sterol Distribution in Sediments from Chaiwobu Lake and Caohai Basin and Its Geochemical Significance

    史继扬; 林树基; 等


    In order to understand the distribution characteristics of biomarkers in source rocks,which may be related to organic input,Quaternary sediments from the Caohai Basin and the Chaiwobu Lake were analyzed for sterols,As a result,various sterols,have been found in the sediments.The composition of sterols in the sediments revealed that cholesterols and cholestadienols are more abundant than their C29 counterparts in the Chaiwobu Lake sediments and that C29 sterols are more abundant in the peats from the Caohai Basin,It is also found that stanol/sterol ratios in clays are higher than in peats.Studies show that organic input to the Chaiwobu Lake is mainly plankton and zooplankton and to the Caohai Basin is mainly terrestrial high plant.The authors have proposed that the relative abundance of C27 or C29 sterane in source rocks may reflect input characteristics to some extent and the stanol/sterol ratios may reflect the redox conditions of the depositional environments.

  11. Carbonate verse silicate Sr isotope in lake sediments and its response to Little Ice Age


    The 87Sr/86Sr ratios of silicate (acid-insoluble, AI) and carbonate (acid-soluble, AS) of the lake sediments from the Daihai Lake, Inner Mongolia, since the last 500 years are measured respectively, indicating that chemical weathering of silicate minerals was in an early stage since the Little Ice Age within the Daihai watershed by combination with mineral constitute, Rb/Sr ratio and CaCO3 content in the sediments. During the Little Ice Age maximum, an evident peak in the 87Sr/86Sr ratios of both silicate and carbonate in sediments suggests that a cold climate condition is unfavorable to dissolving radiogenic strontium from silicate minerals. Meanwhile, the variation of 87Sr/86Sr ratios of silicate and carbonate also reflects a projected warming climate favorable to intensifying chemical weathering after the Little Ice Age. Consequently, the 87Sr/86Sr ratio of both silicate and carbonate in inland lake sediments can be used as an effective proxy of the past climate in single watershed.

  12. Brotherswater, English Lake District: a record of organic and inorganic sediment flux over the past two millenia

    Schillereff, D.; Chiverrell, R.; Boyle, J.; Macdonald, N.; Hooke, J.


    Lake sediments have long been recognised as efficient recorders of geomorphic change through time and they also function as a proportionally large carbon sink within the global C cycle. However, calculating carbon budgets for lake basins can prove challenging due to the spatially variable pattern of sediment accumulation within the basin and the heterogeneous nature of the organic matter accumulating on the lake floor, which can comprise autogenic organic material, eroded soil organic floccules and plant biomass from the catchments. High-resolution (0.5 cm) particle size, geochemical and thermogravimetric data for a series of abyssal lake sediment cores (3 - 5 m length) are used to examine the relationship between hydrological conditioning, sediment dynamics and particulate carbon flux over the past 2000 years for a small upland catchment in the English Lake District (Brotherswater). Core correlation using geochemical and mineral magnetic profiles has facilitated the identification of the spatial pattern of inorganic and organic sediment accumulation within the lake. A well-constrained chronology has been developed, incorporating radionuclide (210Pb, 137Cs and 14C) dating and elemental signatures which reflect the mining history of the catchment (e.g., Pb, Ba and Zn). The role of climatic fluctuations and human activity (e.g., the Little Ice Age, agricultural intensification during Roman and Viking periods) in controlling catchment-to-lake sediment flux is well studied in northwest England, and these phases are reflected in inorganic geochemical markers (e.g., Sr, Zr, K) in the lake sediment cores. Recently accumulated sediments yield geochemical signatures of substantial heavy metal flux (lead, zinc and barium) associated with intensive mining in the catchment, while numerous coarse-grained facies are visible within the silt-dominated lake sediment matrix, which are interpreted as reflecting late-Holocene high-magnitude flood events. Using thermogravimetric (TGA

  13. Evolution of sediment composition of the coastal Lake San Puoto (Latium, Italy in the last two centuries

    Enrico DINELLI


    Full Text Available The sediment composition of the coastal Lake San Puoto (Central Italy was studied to obtain information on its recent environmental evolution (last 200 years. The explorative fieldwork was performed within the framework of the EU-funded PALICLAS Project. Sediment and mass accumulation rates, calculated from 210Pb analysis, show mean values of 0.27 cm y-1 and 0.11 g cm-2 y-1 respectively, with increasing values from 10 cm to the top (i.e. from ca 1960 AD to the present. The evolution of the recent sedimentation of Lake San Puoto is characterized by the interplay of three main components: detrital (either siliciclastic and/or carbonatic, organic-rich and authigenic phases. The first reflects the input from coastal dunes and rocky outcrops; the other two indicate variations in lake productivity. Sedimentological, geochemical, and mineralogical analyses of two cores collected near the center of the lake were used to define five lithological units: i a laminated unit representing the last eutrophication period, starting ca 1925 AD; ii a few turbidite layers, probably due to a lowering of the lake level around 1920 AD; iii a productive phase of the lake, which occurred around the end of the XIX and the beginning of the XX century; iv a coarse siliciclastic sediment interval, possibly deposited following the digging of the channel connecting Lake San Puoto to Lake Lungo; and v an older unit representing the natural allochthonous detritic sedimentation deriving from the present dune deposits surrounding the lake shores. Metal fluxes were calculated for recent times by means of 210Pb sedimentation rates. Zn, Cu and Pb record considerably higher fluxes above 10 cm depth (i.e. 1960 AD, as confirmed by Al-normalized metal depth profiles. Episodes of eutrophication occurred between 1890 and 1920 and between 1925 and the present.

  14. Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth


    Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperaturesincrease, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is importantto predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), andpyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C,and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH4 oxidation activitywas measured in microcosm incubations containing sediments at all temperatures, with the highest CH4 oxidation potential of37.5 mol g1 day1 in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of pmoA and ofthe 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in 13C-labeled DNA obtained bySIP demonstrated that the type I methanotrophs Methylobacter, Methylomonas, and Methylosoma dominated carbon acquisitionfrom CH4 in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature.Methylotrophs were also abundant in the microbial community that derived carbon from CH4, especially in the deeper sediments(depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (R0.82) with the relativeabundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophiccommunities in arctic lake sediments respond to temperature variations.

  15. Pre-aged plant waxes in tropical lake sediments and their influence on the chronology of molecular paleoclimate proxy records

    Douglas, Peter M. J.; Pagani, Mark; Eglinton, Timothy I.; Brenner, Mark; Hodell, David A.; Curtis, Jason H.; Ma, Keith F.; Breckenridge, Andy


    Sedimentary records of plant-wax hydrogen (δDwax) and carbon (δ13Cwax) stable isotopes are increasingly applied to infer past climate change. Compound-specific radiocarbon analyses, however, indicate that long time lags can occur between the synthesis of plant waxes and their subsequent deposition in marginal marine sediments. The influence of these time lags on interpretations of plant-wax stable isotope records is presently unconstrained, and it is unclear whether such time lags also affect lacustrine sediments. We present compound-specific radiocarbon (14Cwax) data for n-alkanoic acid plant waxes (n-C26 to n-C32) from: (1) a sediment core from Lake Chichancanab, Yucatan Peninsula, Mexico, (2) soils in the Lake Chichancanab catchment, and (3) surface sediments from three other lakes in southeastern Mexico and northern Guatemala. 14Cwax ages in the surface sediments are consistently older than modern, and may be negatively correlated with mean annual precipitation and positively correlated with lake catchment area. 14Cwax ages in soils surrounding Lake Chichancanab increase with soil depth, consistent with deep, subsoil horizons being the primary source of lacustrine aged plant waxes, which are likely delivered to lake sediments through subsurface transport. Plant waxes in the Lake Chichancanab core are 350-1200 years older than corresponding ages of bulk sediment deposition, determined by 14C dates on terrestrial plant macrofossils in the core. A δDwax time series is in closer agreement with other regional proxy hydroclimate records when a plant-wax 14C age model is applied, as opposed to the macrofossil-based core chronology. Inverse modeling of plant-wax age distribution parameters suggests that plant waxes in the Lake Chichancanab sediment core derive predominantly from millennial-age soil carbon pools that exhibit relatively little age variance (soils. They also underscore the importance of direct radiocarbon dating of these organic molecules.

  16. A 500,000-Year-Long Sediment Archive of Lake Van in Eastern Anatolia

    Litt, T.; Anselmetti, F. S.; Cagatay, M. N.; Kipfer, R.; Krastel, S.; Schmincke, H.-U.; Sturm, M.


    Lake Van, a large terminal lake in eastern Anatolia (Turkey), holds a key position within a sensitive climate region between the Black Sea, Caspian Sea and Mediterranean Sea. Lake Van extends over 130 kilometers on a high plateau; lake level at present is 1665 meters above sea level. The lake water, up to 450 meters deep, is alkaline (pH ~9.8) and saline (~21.4‰). Its long and partly annually laminated sedimentary record provides an excellent paleoclimate archive because it yields a long and continuous continental sequence that covers several glacial-interglacial cycles spanning more than 500,000 years. Lake Van is therefore a key site to reconstruct Quaternary climate evolution in the near east. Moreover, being located in a tectonically active area bordered by two historically active volcanoes, it holds a unique paleoseismic and volcanic archive. As a closed and saline lake, Lake Van reacts very sensitively to lake level changes caused by any alterations in the hydrological regime in response to climate change. Because the lake is the deepest lake in Anatolia, which, in contrast to other more shallow lakes, likely never dried out in its history, it was identified as the most promising candidate to contain a long and continuous sediment archive. The drilling campaign, supported by the International Continental Scientific Drilling Program (ICDP), operated by the U.S.-based company Drilling, Observation and Sampling of the Earths Continental Crust (DOSECC), was carried on in July and August 2010. DOSECC developed and assembled a new Deep Lake Drilling System (DLDS) that was specifically designed for coring sediments from deep lakes and that was first operated in Lake Van. The DLDS worked at water depths of up to 360 meters. Cores from 140 meters (Northern Basin site) and 220 meters (AhlatRridge site) below the lake bed depth were retrieved. To obtain a complete sedimentary section, the two sites were cored multiple times. Total length of all parallel cores

  17. Silicone passive equilibrium samplers as ‘chemometers’ in eels and sediments of a Swedish lake

    Jahnke, Annika; Mayer, Philipp; McLachlan, Michael S.


    Passive equilibrium samplers deployed in two or more media of a system and allowed to come to equilibrium can be viewed as ‘chemometers’ that reflect the difference in chemical activities of contaminants between the media. We applied silicone-based equilibrium samplers to measure relative chemical...... activities of seven ‘indicator’ polychlorinated biphenyls (PCBs) and hexachlorobenzene in eels and sediments from a Swedish lake. Chemical concentrations in eels and sediments were also measured using exhaustive extraction methods. Lipid-normalized concentrations in eels were higher than organic carbon...... ratios is consistent with the sorptive capacity of lipids exceeding that of sediment organic carbon from this ecosystem by up to 50-fold. Factors that may contribute to the elevated activity in sediments are discussed, including slower response of sediments than water to reduced emissions, sediment...

  18. A preliminary evaluation of the DDT contamination of sediments in lakes Natron and Bogoria (Eastern Rift Valley, Africa).

    Bettinetti, Roberta; Quadroni, Silvia; Crosa, Giuseppe; Harper, David; Dickie, Jennifer; Kyalo, Margaret; Mavuti, Kenneth; Galassi, Silvana


    Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern Rift Valley, supporting large populations of lesser flamingos (Phoeniconaias minor), were analysed for DDT residues. Physical-chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp'DDE, whilst equal concentrations of pp'DDT and pp'DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9-30.9 ng g(-1) d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria basins seems to be quite moderate. Nevertheless, the pp'DDE/pp'DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport or dust from relatively close-by old pesticides storage sites.

  19. Spatial distribution and historical records of mercury sedimentation in urban lakes under urbanization impacts.

    Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Deng, Hong; Xu, Bo; Ding, Jing; Gao, Jin-Bo; Hong, You-Wei; Wong, Ming-Hung


    China is assumed one of the largest contributors to the world's total mercury (Hg) emissions, with a rapid increase in anthropogenic Hg emissions. However, little is known about Hg fate and transport in urban areas of China. In this study, total Hg contents in surface (0-5 cm) sediments from lakes in 14 parks (3 in the central urban core (CUC) area, 5 in the developed urban (DDU) area, 2 in the developing urban (DIU) area, and 4 in the suburban (SU) area) and (210)Pb-dated sediment cores from lakes in 5 parks (3 in the CUC and 2 in the DDU) in Shanghai were assessed to compare current patterns (urbanization effect) with the historical records of Hg emissions over the past century. Total Hg content in surface sediments showed a clear urbanization pattern. Dated sediment cores revealed a 2-3 fold increase in total Hg content, while Hg fluxes exponentially increased from ~1900 to present and accelerated since 1990 when China's economy and urbanization booms started. Anthropogenic Hg fluxes in post-2000 ranged from 253 to 1452 μg m(-2) yr(-1), 2-7 times greater than preindustrial (pre-1900) Hg fluxes. Total Hg and Pb contents in both surface sediments and sediment cores were highly correlated and Hg flux in sediment cores also significantly correlated with annual coal consumption in the period 1949-2008. The significant correlations suggest that coal combustion is a major source of Hg emission in Shanghai.

  20. Surficial geology and distribution of post-impoundment sediment in Las Vegas Bay, Lake Mead

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.; Rendigs, Richard R.


    Sidescan sonar imagery and seismic-reflection profiles were collected in the northwestern part of Las Vegas Bay to map the distribution and volume of sediment that has accumulated in this part of Lake Mead since impoundment. The mapping suggests that three ephemeral streams are the primary source of this sediment, and of these, Las Vegas Wash is the largest. Two deltas off the mouth of Las Vegas Wash formed at different lake elevations and account for 41% of the total volume of post-impoundment sediment within the study area. Deltas off the other two washes (Gypsum and Government) account for only 6% of the total volume. The sediment beyond the front of the deltas is primarily mud, and it only occurs in valley floors, where it forms a flat-lying blanket that is mostly less than 1.5 m thick. Although a thin layer, the fine-grained sediment accounts for approximately 53% of the total post-impoundment sediment volume of 5.7 x 106 m3 that has accumulated in the study area. This sediment appears to have been transported several kilometers from the river sources by density flows.

  1. Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes

    Yin, Runsheng; Feng, Xinbin; Hurley, James P.; Krabbenhoft, David P.; Lepak, Ryan F.; Kang, Shichang; Yang, Handong; Li, Xiangdong


    The Tibetan Plateau (TP), known as the “Third Pole”, is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ 202Hg in Lake Qinghai (−4.55 to −3.15‰) and Nam Co (−5.04 to −2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ 200Hg: +0.05 to +0.10‰) and odd-Hg (∆ 199Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ 200Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ 199Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ 199Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes. PMID:26996936

  2. Lead isotope ratios in six lake sediment cores from Japan Archipelago: Historical record of trans-boundary pollution sources

    Hosono, Takahiro, E-mail: [Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Alvarez, Kelly [Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Kuwae, Michinobu [Senior Research Fellow Center, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)


    Sediment cores from six lakes situated from north to south on the Japanese Archipelago were collected during 2009–2010 to investigate the hypothesis that deposition of lead (Pb) was coming from East Asia (including China, South Korea and eastern part of Russia). Accumulation rates and ages of the lake sediment were estimated by the {sup 210}Pb constant rate of supply model and {sup 137}Cs inputs to reconstruct the historical trends of Pb accumulation. Cores from four lakes located in the north and central Japan, showed clear evidence of Pb pollution with a change in the {sup 206}Pb/{sup 207}Pb and {sup 208}Pb/{sup 207}Pb ratios in the recent sediment as compared to the deeper sediment. Among the six studied lakes, significant inputs of anthropogenic lead emissions were observed at Lake Mikazuki (north Hokkaido in north Japan), Lake Chokai (north of Honshu), and Lake Mikuriga (central part of Honshu). Pb isotopic comparison of collected core sediment and previously reported data for wet precipitation and aerosols from different Asian regions indicate that, before 1900, Pb accumulated in these three lakes was not affected by trans-boundary sources. Lake Mikazuki started to receive Pb emissions from Russia in early 1900s, and during the last two decades, this lake has been affected by trans-boundary Pb pollution from northern China. Lake Chokai has received Pb pollutant from northern China since early 1900s until 2009, whereas for the Lake Mikuriga the major Pb contaminant was transported from southern China during the past 100 years. The results of our study demonstrate that Japan Archipelago has received trans-boundary Pb emissions from different parts of East Asian region depending on location, and the major source region has changed historically. - Highlights: • Historical trend of Pb pollution was recorded in six Japanese Lakes. • Pb concentration and Pb isotope ratios were determined for sediment cores. • High [Pb] and less radiogenic Pb isotope ratios

  3. Preliminary estimation of Lake El'gygytgyn water balance and sediment income

    G. Fedorov


    Full Text Available Modern process studies of the hydrologic balance of Lake El'gygytgyn, central Chukotka, and the sediment income from the catchment were carried out during a field campaign in spring and summer 2003. Despite high uncertainties due to the limited data, the results provide important first estimates for better understanding the modern and past sedimentation processes in this basin. Formed ca. 3.6 million years ago as a result of a meteorite impact, the basin contains one of the longest paleoclimate records in the terrestrial Arctic. Fluvial activity is concentrated over the short snowmelt period (about 20 days in second part of June. Underground outflow plays a very important role in the water balance and predominates over surface outflow. The residence time of the lake water is estimated to be about 100 yr.

  4. The magnetic properties of the Lake Bolshoe Yarovoe (Altai Region, Russia) sediments

    Kosareva, Lina; Nourgaliev, Danis; Nurgalieva, Nuriia; Shcherbakov, Valeriy; Kuzina, Diliara; Antonenko, Vadim; Akhmerov, Rinaz; Evtugyn, Vladimir; Vorob'ev, Vyacheslav


    Magnetic minerals of modern lake sediments provide unique source of information for climate changes, regionally and globally as environmental variations are recorded by them with high resolution. Here we report results of magnetic analysis of the endorheic bitter-salty lake Bolshoe Yarovoe located in the Altai Region, Russia. The lake is the deepest one in the Kulunda Steppe with the average depth 4 m and with the catchment area about 560 km2. Five cores were drileld during field research conducted by the Institute of Geology and Petroleum Technologies (Kazan Federal University, Russia) in 2008. Average length of cores is 4 m. The samples were studied using radiocarbon dating, magnetic susceptibility, NRM measurements, coercivity spectrometry, thermomagnetic analysis, TEM and SEM microscopy. The main components of the sediments magnetization, their variability, defined features of sedimentation processes, also the contribution of the paramagnetic, ferromagnetic, superparamagnetic components are identified. Data variability of the paramagnetic component revealed that the lower part of the section is characterized by a gradual increase in revenues of the clay material. The presence of erosion was detected around of 7500 years ago marking occurrence of a fall of the lake level during this period. After this the flow of clay particles was steady with small fluctuations only, indicating the stabilization of sedimentation processes. Ferromagnetic fraction is mainly represented by magnitofossils of different forms, sizes and grain preservation. Such changes may be related to many factors, such as climate, nutrient availability, and environmental variability. Possible relationships between magnitofossil morphology, their magnetic signal and the depositional environment changes are proposed. The work was carried out according to the Russian Government's Program of Competitive Growth of Kazan Federal University.

  5. Geochemical control processes and potential sediment toxicity in a mine-impacted lake.

    Adeleke, Solomon Babatunde; Svensson, Bo H; Yekta, Sepehr Shakeri; Adeleye, Michael Mayowa


    Geochemical parameters and major ion concentrations from sediments of a freshwater lake in the town of Åtvidaberg, southeastern, Sweden, were used to identify the geochemical processes that control the water chemistry. The lake sediments are anoxic, characterized by reduced sulfur and sulfidic minerals. The hypothesis tested is that in sulfidic-anaerobic contaminated sediments, the presence of redox potential changes creates a favorable condition for sulfide oxidation, resulting in the release of potentially toxic metals. The acid volatile sulfide (AVS) contents ranged from 5.5 μmol/g to 16 μmol/g of dry sediment. Comparison of total mine tailing metals (∑mine tailing metals) with simultaneously extracted metals (SEM) in sediments indicates that up to 20% of the ∑mine tailing metals are bound to the solid phase as AVS. Consequently, the AVS and SEM analysis classified all sediment samples as potentially toxic in terms of heavy metal concentrations (i.e., SEM to AVS ratio distribution > 1). Evaluation of hydrogeochemical data suggests that calcite dissolution, iron (III) oxyhydroxysulfate mineral jarosite (H-jarosite) precipitation, hematite precipitation, and siderite precipitation are the most prevailing geochemical processes that control the geochemical interactions between the water column and sediment in a mine-impacted lake. The geochemical processes were verified and quantified using a chemical equilibrium modeling program, Visual MINTEQ, Ver 3.1, beta. The identified geochemical processes create an environment in which the characteristics of sulfate-rich waters and acidic-iron produce the geochemical conditions for acid mine drainage and mobilization of toxic metals.

  6. Effects of increasing temperatures on methane concentrations and methanogenesis during experimental incubation of sediments from oligotrophic and mesotrophic lakes

    Fuchs, Andrea; Lyautey, Emilie; Montuelle, Bernard; Casper, Peter


    Global warming is expected to raise temperatures in freshwater lakes, which have been acknowledged to contribute up to 10% of the atmospheric methane concentrations. Increasing temperature enhances methane production and oxidation rates, but few studies have considered the balance between both processes at experimentally higher temperatures within lake sediments. The temperature dependence of methane concentrations, methane production rates, and methanogenic (mcrA) and methanotrophic (pmoA) community size was investigated in intact sediment cores incubated with aerobic hypolimnion water at 4, 8, and 12°C over 3 weeks. Sediment cores of 25 cm length were collected at two temperate lakes—Lake Stechlin (Germany; mesotrophic-oligotrophic, maximum depth 69.5 m) and Lake Geneva (France/Switzerland; mesotrophic, maximum depth 310 m). While methane production rates in Lake Stechlin sediments did not change with increasing temperatures, methane concentrations decreased significantly. In contrast, methane production rates increased in 20-25 cm in Lake Geneva sediments with increasing temperatures, but methane concentrations did not differ. Real-time PCR demonstrated the methanogenic and methanotrophic community size remained stable independently of the incubation temperature. Methane concentrations as well as community sizes were 1-2 orders of magnitude higher in Lake Stechlin than in Lake Geneva, while potential methane production rates after 24 h were similar in both lakes, with on average 2.5 and 1.9 nmol g-1 DW h-1, respectively. Our results suggest that at higher temperatures methane oxidation could balance, and even exceed, methane production. This suggests that anaerobic methane oxidation could be involved in the methane balance at a more important rate than previously anticipated.


    Ahmad Ismail; Chee Kong YAP; Fong Fei Chan


    Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human activities mainly from residents and transportation. A study was conducted to determine the distribution and sources of heavy metals (Cd, Cu and Zn) in the sediments of Kelana Jaya Lakes. Concentrations of Cd, Cu, and Zn for surface sediment were determined by using aqua-regia method and sequential extraction technique. Total Cd concentrations ranged from 0.48 μg/g to 2.68 μg/g dry weight (dw) for all lakes. Total Cd concentrations in sediment of all lakes exceeded CCME (Canadian Council of Ministers of the Environment, 2001) guidelines. Total Cu concentrations ranged from 7.37μg/g to 73.6 μg/g (dw). Only Cu concentration in one lake exceeded the CCME guidelines besides having the highest mean concentration among all. Total Zn concentrations ranged from 107 μg/g to 529 μg/g (dw). Again, The Zn concentrations in three lakes were found to exceed CCME guidelines for Zn concentration in freshwater sediment. Geochemical study on sediment revealed that nonresistant fractions for Cd, Cu and Zn for other lakes there Cu and Zn indicated that lakes in the park, especially near oxidation pond and monsoon drains, could have received anthropogenic metals from domestic wastes. Rehabilitation program and regular biomonitoring at Kelana Jaya Lakes are therefore recommended.

  8. Bioavailable phosphorus (P) reduction is less than mobile P immobilization in lake sediment for eutrophication control by inactivating agents.

    Wang, Changhui; He, Rui; Wu, Yu; Lürling, Miquel; Cai, Haiyuan; Jiang, He-Long; Liu, Xin


    Phosphorus (P) immobilization by inactivating agents in the sediment of eutrophic lakes to reduce immediately available P in lake water is often crucial for mitigating nuisance eutrophication symptoms, such as cyanobacterial blooms. Macrophytes and phytoplankton, however, can directly utilize P from the sediment for growth. Accordingly, a comprehensive analysis of the P bioavailability in lake sediment amended with two promising P-inactivation agents, namely Phoslock(®) and drinking water treatment residue (DWTR), was investigated in both short- and long-term studies (20 and 180 d). Phosphorus-availability was assessed using six chemical extraction methods and Hydrilla verticillata and Microcystis aeruginosa growth tests. The results showed that Phoslock(®) and DWTR significantly reduced mobile P (NH4Cl and Na2S2O4/NaHCO3 extractable P) in lake sediment, while P bioavailability that was assessed by different methods showed considerable deviations. Interestingly, appropriate bioavailable P chemical extraction methods were determined based on linear correlation analysis, and further comparison indicated that reduction of bioavailable P by DWTR (P) and Phoslock(®) (P) were clearly less than the mobile P immobilization (>75%) at recommended dosages, which was probably caused by the capability of macrophyte and cyanobacteria to utilize various fractions of P (except the residual P) in amended sediment under proper illumination. Therefore, DWTR and Phoslock(®) can effectively reduce P release from lake sediment, but the potential bioavailable P may pose uncertainties for eutrophication control in lakes that typically have regular sediment re-suspension. Overall, an evaluation of the bioavailable P pool in the lake ecosystem should be essential for successful lake geo-engineering.

  9. Late Glacial and Holocene environmental history of Wielkopolska region (western Poland) recorded in sediments of Strzeszyńskie Lake and Kierskie Lake

    Pleskot, Krzysztof; Szczuciński, Witold; Tjallingii, Rik; Makohonienko, Mirosław; Nowaczyk, Norbert; Brauer, Achim


    The growing amount of publications concerning reconstructions of Late Glacial and Holocene environment based on analysis of lake sediments gives us robust insight into general patterns of that record. However, it is still challenging to decipher processes and events that occurred on local scale, as they record may be strongly affected by the type, catchment, size and depth of a lake. Therefore in the present study we focus on application of sedimentological and geochemical methods in order to reveal environmental history from two neighbouring lakes located within city of Poznań, Wielkopolska (western Poland). The lake sediments analysis cover Late Glacial and Holocene in case of smaller Strzeszyńskie Lake (SL) and the last 8 ka in deeper Kierskie Lake (KL). The study is based on two 8.5 (SL) and 14 (KL) m long sediment cores, which were described and analyzed in thin sections and on smear slides. The relative chemical composition variations within the cores were measured using an X-ray fluorescence (XRF). Moreover, the cores were measured for magnetic susceptibility and sampled for pollen analysis. The chronology has been established by a AMS 14C dating of bulk samples of lake sediments. To assess the reservoir effect, selected samples were analyzed for soluble and residual carbon fractions. Our results suggest the onset of authigenic sedimentation in SL in Allerød. The sediments from this period are characterized by high organic matter and low carbonate content. This trend changed into opposite at the beginning of the Younger Dryas, while at its termination sediments again became more organic. The transition to Holocene is marked by spread of Betula forest, gradual increase in magnetic susceptibility and Ca content together with decreasing organic matter and clastic input. During Preboreal and Boreal period the relatively stable conditions was noted. Then, ca. 8.5 ka BP, sharp decrease in magnetic susceptibility occurred coincided with deciduous forest

  10. Anthropogenic mercury deposition in Flin Flon Manitoba and the Experimental Lakes Area Ontario (Canada): A multi-lake sediment core reconstruction.

    Wiklund, Johan A; Kirk, Jane L; Muir, Derek C G; Evans, Marlene; Yang, Fan; Keating, Jonathan; Parsons, Matthew T


    High-resolution records of anthropogenic mercury (Hg) deposition were constructed from 9 lakes located 5-75km from the Flin Flon, Manitoba smelter (formerly one of North America's largest atmospheric Hg point sources) and 5 lakes in Experimental Lakes Area (ELA), Ontario; a region remote from major Hg point sources. Anthropogenic Hg deposition, as both a flux and inventory, was determined after accounting for lake-specific natural Hg background concentrations, changes in sedimentation and sediment focusing. Results show that records of anthropogenic flux and inventory of Hg were remarkably consistent among the ELA lakes, but varied by 2 orders of magnitude among Flin Flon lakes. The relation between Hg inventories (normalized for prevailing wind direction) and distance from the smelter was used to estimate the total Hg fallout within a 50km radius in 5year time-steps, thus providing a quantitative spatial-temporal Hg depositional history for the Flin Flon region. The same relation solved for 8 cardinal directions weighted by the inverse of the previously applied wind direction normalization generates a map of Hg inventory and deposition on the landscape (Supplementary video). This novel application of sediment core data constructs a landscape model and allows for a visualization of contaminant deposition with respect to a point major source in both space and time. The propensity for Hg to undergo long-range, even global transport explains why Hg deposition within 50km of Flin Flon was ~11% of estimated releases. That is until smelter releases were reduced >10-fold (post-2000), after which observed deposition exceeded smelter releases, suggesting landscape re-emission/remobilization of legacy Hg is a major ongoing regional source of Hg.

  11. Study of heavy metal speciation in branch sediments of Poyang Lake


    This study concentrates on the environmental pollution level of sediments in the six branches of Poyang Lake, the biggest fresh water lake in China. This is the first systematic report on the speciation analysis of heavy metals (Cu, Co, Cd, Pb, and Ni) in the six branches of the lake. A reported analytical procedure involving a five-step sequential extraction is used for the partition of particulating heavy metals. The sediment samples are analyzed using flame atomic absorption spectroscopy (FAAS). Experimental results obtained from five replicate samples of fluvial bottom surface sediments at the sampling points demonstrated that the relative standard deviation of the sequential extraction procedure was generally better than 10% (Cd except). The average extracted contents of the five elements,analyzed after all five steps, are found to be (mg/kg) for Cu: 26.89, Co: 16.25, Cd: 1.08, Pb: 37.98, and Ni: 20.46. The content of the exchangeable species was generally lower. Except Cu, the percentage of the species bond to organic matter was lower than 20%. The fractions containing the most metal for Cu, Co, and Ni were the residues (52.26%, 45.28%, and 74.82%, respectively).

  12. Assessment of Heavy Metal Pollution in Sediments of Inflow Rivers to Lake Taihu, China.

    Niu, Yong; Niu, Yuan; Pang, Yong; Yu, Hui


    Lake Taihu, the third-largest freshwater body in China, has many functions, including drinking water supply, flood control, cultivation, navigation, and tourism. In this study, sediment samples were collected at 31 sites from 11 inflow rivers in 2012, to investigate the distribution and concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr), and to assess their potential ecological risk. The highest mean concentration was found for Zn, followed by Cu, Cr, Pb, and Ni. Generally, heavy metal pollution was more serious in Wu Jingang River and Caoqiao River, probably because they receive large amounts of wastewater from various local industrial enterprises. The potential ecological risk values of the heavy metals were larger than 120 in more than 25.8% of the sediment samples, indicating a very high risk. The largest ecological risk was due to copper. Furthermore, the results of a principal component analysis and subsequent analysis of variance showed that heavy metal concentrations in the sediment of inflow rivers were higher than those of the lake, which created a large hazard for the aquatic ecosystems of Lake Taihu.

  13. 20th-century glacial-marine sedimentation in Vitus Lake, Bering Glacier, Alaska, U.S.A.

    Molnia, B.F.; Post, A.; Carlson, P.R.


    Vitus Lake, the ice-marginal basin at the southeastern edge of Bering Glacier, Alaska, U.S.A., is a site of modern, rapid, glacial-marine sedimentation. Rather than being a fresh-water lake, Vitus Lake is a tidally influenced, marine to brackish embayment connected to the Pacific Ocean by an inlet, the Seal River. Vitus Lake consists of five deep bedrock basins, separated by interbasinal highs. Glacial erosion has cut these basins as much as 250 m below sea level. High-resolution seismic reflection surveys conducted in 1991 and 1993 of four of Vitus Lake's basins reveal a complex, variable three-component acoustic stratigraphy. Although not fully sampled, the stratigraphy is inferred to be primarily glacial-marine units of (1) basal contorted and deformed glacial-marine and glacial sediments deposited by basal ice-contact processes and submarine mass-wasting; (2) acoustically well-stratified glacial-marine sediment, which unconformably overlies the basal unit and which grades upward into (3) acoustically transparent or nearly transparent glacial-marine sediment. Maximum thicknesses of conformable glacial-marine sediment exceed 100 m. All of the acoustically transparent and stratified deposits in Vitus Lake are modern in age, having accumulated between 1967 and 1993. The basins where these three-part sequences of "present-day" glacial-marine sediment are accumulating are themselves cut into older sequences of stratified glacial and glacial-marine deposits. These older units outcrop on the islands in Vitus Lake. In 1967, as the result of a major surge, glacier ice completely filled all five basins. Subsequent terminus retreat, which continued through August 1993, exposed these basins, providing new locations for glacial-marine sediment accumulation. A correlation of sediment thicknesses measured from seismic profiles at specific locations within the basins, with the year that each location became ice-free, shows that the sediment accumulation at some locations

  14. Preliminary Analysis of Life within a Former Subglacial Lake Sediment in Antarctica

    Gavin Burns


    Full Text Available Since the first descriptions of Antarctic subglacial lakes, there has been a growing interest and awareness of the possibility that life will exist and potentially thrive in these unique and little known environments. The unusual combination of selection pressures, and isolation from the rest of the biosphere, might have led to novel adaptations and physiology not seen before, or indeed to the potential discovery of relic populations that may have become extinct elsewhere. Here we report the first microbiological analysis of a sample taken from a former subglacial lake sediment in Antarctica (Lake Hodgson, on the Antarctic Peninsula. This is one of a number of subglacial lakes just emerging at the margins of the Antarctic ice sheet due to the renewed onset of deglaciation. Microbial diversity was divided into 23.8% Actinobacteria, 21.6% Proteobacteria, 20.2% Planctomycetes and 11.6% Chloroflexi, characteristic of a range of habitat types ( Overall, common sequences were neither distinctly polar, low temperature, freshwater nor marine. Twenty three percent of this diversity could only be identified to “unidentified bacterium”. Clearly these are diverse ecosystems with enormous potential.

  15. Aliphatic hydrocarbons in sediment cores from the southern basin of Lake Michigan

    Doskey, P.V. [Argonne National Lab., IL (United States). Environmental Research Division; Andren, A.W. [Univ. of Wisconsin, Madison, WI (United States). Water Chemistry Program


    Aliphatic hydrocarbons in sediments of the southern basin of Lake Michigan have planktonic, terrigenous, and petroleum residue origins. Surficial sediments collected near the eastern shore in 60-80 m of water contained more petroleum residue and planktonic hydrocarbons and exhibited less terrigenous character than sediments collected from the deepest location in the basin. Petroleum residue inputs have increased since 1900 as evidenced by a change in the flux of an unresolved complex mixture (UCM) of hydrocarbons from 6 ng/cm{sup 2}{center_dot}yr to a flux of approximately 100 ng/cm{sup 2}{center_dot}yr in 1980. Sediment profiles of the UCM exhibited subsurface concentration maxima that may be due to reduced inputs of combustion products or feeding by oligochaetes. Profiles of n-C{sub l7} and pristane indicated that planktonic n-alkanes undergo degradation in the aerobic, mixed zone of the sediments.

  16. Carbon mineralization and oxygen dynamics in sediments with deep oxygen penetration, Lake Superior

    Li, Jiying; Crowe, Sean Andrew; Miklesh, David


    To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep...... penetration is explained by low sedimentation rates (0.01–0.04 cm yr−1), high solubility of oxygen in freshwater, and a shallow (∼ 2 cm) bioturbation zone. In response mainly to oxygen variations in the bottom waters, the sediment oxygen penetration varied seasonally by as much as several centimeters......, suggesting that temporal variability in deeply oxygenated sediments may be greater than previously acknowledged. The oxygen uptake rates (4.4–7.7 mmol m−2 d−1, average 6.1 mmol m−2 d−1) and carbon mineralization efficiency (∼ 90% of deposited carbon) were similar to those in marine hemipelagic and pelagic...

  17. Accelerator-mass spectrometer (AMS) radiocarbon dating of Pleistocene lake sediments in the Great Basin

    Thompson, R.S.; Toolin, L.J.; Forester, R.M.; Spencer, R.J.


    Pleistocene lake sediments in the Great Basin typically contain little organic carbon, and thus are difficult to date reliably by conventional radioccarbon methods. Paleoenvironmental data are abundant in these sediments, but are of limited value without adequate age controls. With the advent of accelerator-mass spectrometer (AMS) radiocarbon dating, it is now possible to date these paleolacustrine sediments. AMS dates were obtained on sediment cores from the Bonneville, Franklin, and Lahontan Basins. In the Bonneville Basin, the AMS-based chronology compares well with other chronologies constructed from dated shore-zone features. In the Bonneville and Franklin basins, AMS dates delimit unconformities not apparent by other means. We found that dispersed organic carbon from sediments deposited during relatively freshwater intervals provided apparently reliable AMS radiocarbon dates. Carbonate microfossils from the Lahontan Basin also produced results that appear reasonable, while bulk carbonate yielded erroneous results. ?? 1990.

  18. Spatial Assessment of the Effect of Sediment Quality on the Nutrient Levels in Shallow Waters: Cernek Lake Case

    Hüseyin Cüce


    Full Text Available This study was conducted to determine the water-sediment quality and trophic status changes of Cernek Lake located in the Kızılırmak Delta (one of the most important wetlands in Turkey and protected as a Ramsar site. The main objective, was evaluated and examined the effects on trophic level of surface water that the layers of lake sediments can create. In the study, the periodic exchange on trophic level have been evaluated with Geographic Information Systems (GIS by identifying existing water of lake and sediment quality of lake. Spatial analysis was realized for water and sediment quality parameters (pH, salinity, Secchi disc depth and chlorophyll-a, total phosphate and total organic carbon (TOC concentrations. The results of field studies conducted at Cernek Lake for three seasons (2010-2011 showed that the sediments contain high phosphate (annual average 541 mg / kg PO4-P, dry weight and high organic carbon content (annual average 22.4 G / kg TOC, Dry weight. During the summer, Carlson Index values relatively declined during this period compared to autumn (81 to 79, but the eutrophic structure of the lake is still found to be high character. Findings, showed that the contaminated lake sediment layer would be highly effective in trophic level of the lake therefore it has revealed the necessity of taking measures for eutrophication. According to the results of study, taking the medium and long term measures to eutrophication and implementation of the strategic action plan is required.

  19. Elucidating the biogeochemical roles of novel microorganisms from oligotrophic Lake Superior sediments

    Sheik, C.


    Lake Superior (LS) is Earth's largest lake in surface area and fifth largest by volume, yet little is known of the microbial life that drives carbon, nitrogen and sulfur cycles, especially in sediments. LS sediments are typically low in organic matter due to low concentrations of phosphorus in overlying water that constrain primary productivity. Yet, LS sediments are biogeochemically active and have been shown to have oxygen consumption rates akin to the pelagic ocean. Furthermore, microbial activity, potentially from sediments has been suggested for increasing nitrate concentrations in overlying waters. Together, LS is an interesting contrast to highly productive freshwater and coastal marine and less productive pelagic ocean sediments. Here I will present a mixture of results, both spatially and with sediment depth, from cores taken from six stations in the western arm of LS in July 2015. Overall, station locations were quite different in total carbon, nitrogen and microbial community structure. The variability observed likely stems from land influence, as some stations are more coastal, thus have higher rates of sedimentation, allochthonous carbon inputs and productivity than pelagic superior sites. Pelagic stations show a steady decline in both carbon and nitrogen with depth. Microbial communities, from the pelagic sediments are quite different from coastal communities. However, more interesting is that microbial community structure changes abruptly with depth in the sediment, suggesting that microbial membership is changing with geochemistry. At these pelagic stations, geochemical evidence of denitrification via traditional and ANAMMOX pathways and a pronounced sulfate methane transition zone have been shown previously. We see evidence of both denitrification processes in metagenomes and 16S rRNA gene libraries. Additionally, methanogen abundance generally increases with depth, while sulfate reducing bacteria peak and decline mid-core. Similarly, recovered

  20. Estimates of minimum shaking intensity required to induce liquefaction and sediment redistribution in southern Cascadia forearc lakes

    Morey, A. E.; Meigs, A.; Gavin, D. G.


    Sedimentary sequences from several southern Cascadia forearc lakes near the California/Oregon border contain anomalous deposits suspected to have formed as the result of strong ground motions in great earthquakes. We compared the sedimentary sequences from two pairs of lakes that lie ~30 km above the subduction interface, to determine the impact of shaking on deposit characteristics. We find that disturbance event deposit characteristics depend on the geomorphologic and geologic setting of each lake, and thick minerogenic layers occur in lakes with deltas or slides through which source water flows. Proximal lake pair (~140 km from the trench): These lakes are cirque lakes ~20 km from one another. One lake has visible silty clay layers, and the other only has slight changes in density and mineral content not visually apparent. Deposits may be preceded by, or coincident with, a layer of coarse plant macrofossils. Distal lake pair (~185 km from the trench): These lakes were created by the same landslide and contain thick disturbance event deposits with a high percentage of minerogenic sediment. The smaller lake contains a record of pseudo-annual flood deposits that have been interpreted as a time series of erosion magnitudes (see poster by Gavin et al. also in this session). The thickest of these events fall above a strongly linear relationship, suggesting a separate process (such as earthquakes). The thick deposits grade from organic-rich to mineral-rich, and are capped by a thin layer of fine-grained silty clay. A sequence of progressively thinner deposits follows each thick layer, and may reflect post-earthquake erosional events. The larger of the two landslide-dammed lakes contains thick minerogenic deposits with normal grading, and appear to be coeval with the thickest layers in the smaller lake. The upper portion of this record is well-dated, and likely contains a deposit resulting from the 1700AD earthquake. We hypothesize that strong ground motions cause

  1. Variation characteristics of heavy metals and nutrients in the core sediments of Taihu Lake and their pollution history


    The sedimentary environment change, trophic evolution and heavy metals pollution history of the northern Taihu Lake in the last 100 years are studied according to the sedimentary geochemical proxies of the core sediments, such as grain size, nutrients, heavy metals, diatom, etc. The nutrients in the sediments depended mainly on the lake internal circulation and the heavy metals were from natural geogenic sources before the 1920s, which were not influenced by human activities generally, and grain size was one of the key factors influencing heavy metals content in the sediments.The alternation of manner and strength of human activities in Taihu Lake catchment before and after the 1920s made the lake sediments coarser, and hence heavy metals and TP content decreased contrasted with that before the 1920s. TP content in sediments and water increased from the 1950s to late 1970s due to anthropogenic pollutants discharge, and the lake belonging to mesotrophic state.TN and TOC content and C/N ratio increased due to the increasing external pollutants into Taihu Lake by human activities, TP content also increased obviously in water and sediments, and the diatom association was dominated by eutrophic species since the late 1970s, indicating the eutrophication state of Taihu Lake in this period. Meanwhile the increasing in heavy metals content, such as Cu, Mn,Ni, Pb and Zn, and their proportion of valid fractions in the sediments indicates that they all result from human pollutants since the late 1970s. The heavy metals in the surface sediments have certain potential biological toxicity due to the higher SEM/AVS ratio.

  2. Laboratory measurements of physical, chemical, and optical characteristics of Lake Chicot sediment waters

    Witte, W. G.; Whitlock, C. H.; Usry, J. W.; Morris, W. D.; Gurganus, E. A.


    Reflectance, chromaticity, diffuse attenuation, beam attenuation, and several other physical and chemical properties were measured for various water mixtures of lake bottom sediment. Mixture concentrations range from 5 ppm to 700 ppm by weight of total suspended solids in filtered deionized tap water. Upwelled reflectance is a nonlinear function of remote sensing wave lengths. Near-infrared wavelengths are useful for monitoring highly turbid waters with sediment concentrations above 100 ppm. It is found that both visible and near infrared wavelengths, beam attenuation correlates well with total suspended solids ranging over two orders of magnitude.

  3. Heavy metals seasonal variability and distribution in Lake Qaroun sediments, El-Fayoum, Egypt

    Redwan, Mostafa; Elhaddad, Engy


    This study was carried out to investigate the seasonal variability and distribution of heavy metals "HMs" (Fe, Mn, Co, Cr, Cu, Ni, Pb, Zn and V) in the bottom sediments of Lake Qaroun, in Egypt. The samples were collected from 10 sites in summer and winter seasons in 2015. Total metals concentrations were measured using inductively coupled plasma spectrometer. Multivariate techniques were applied to analyse the distribution and potential source of heavy metals. The mean seasonal concentrations follow a descending order of Fe > Mn > V > Zn > Cr > Ni > Cu > Co > Pb. The mean concentrations of HMs in sediments during summer were higher than the concentrations during winter and above the average world shale values, except for Pb, suggesting potential adverse toxicity to aquatic organisms. All metals showed enrichment during summer and winter at sites S3 and S5 in the southeastern parts of the lake due to the heavy discharge of contaminants from El-Bats and El-Wadi drains. Principal component analysis results suggested two principal components controlling HMs variability in sediments, which accounted for 63.9% (factor 1: Co, Cr, Cu, Ni, Zn, Pb and V), 15.9% (factor 2: Mn and Fe) during summer, and 76.7% (factor 1: Fe, Co, Cr, Cu, Ni, Zn, Pb and V), 13.8% (factor 2: Mn) during winter of the total variance. Geo-accumulation index (Igeo) showed some pollution risk at the southeastern and southern parts (sites S3 and S5). Dilution during winter, concentration during summer, impact of non-point sources from different agricultural, industrial, municipal sewage and fish farms in the southern part of Lake Qaroun, adsorption and salt dissolution reactions and lithogenic sources are the main controlling factors for HMs in the study area. Monitoring of contaminant discharge at Lake Qaroun should be introduced for future remediation and management strategies.

  4. Paleomagnetism and environmental magnetism of GLAD800 sediment cores from Bear Lake, Utah and Idaho

    Heil, C.W.; King, J.W.; Rosenbaum, J.G.; Reynolds, R.L.; Colman, Steven M.


    A ???220,000-year record recovered in a 120-m-long sediment core from Bear Lake, Utah and Idaho, provides an opportunity to reconstruct climate change in the Great Basin and compare it with global climate records. Paleomagnetic data exhibit a geomagnetic feature that possibly occurred during the Laschamp excursion (ca. 40 ka). Although the feature does not exhibit excursional behavior (???40?? departure from the expected value), it might provide an additional age constraint for the sequence. Temporal changes in salinity, which are likely related to changes in freshwater input (mainly through the Bear River) or evaporation, are indicated by variations in mineral magnetic properties. These changes are represented by intervals with preserved detrital Fe-oxide minerals and with varying degrees of diagenetic alteration, including sulfidization. On the basis of these changes, the Bear Lake sequence is divided into seven mineral magnetic zones. The differing magnetic mineralogies among these zones reflect changes in deposition, preservation, and formation of magnetic phases related to factors such as lake level, river input, and water chemistry. The occurrence of greigite and pyrite in the lake sediments corresponds to periods of higher salinity. Pyrite is most abundant in intervals of highest salinity, suggesting that the extent of sulfidization is limited by the availability of SO42-. During MIS 2 (zone II), Bear Lake transgressed to capture the Bear River, resulting in deposition of glacially derived hematite-rich detritus from the Uinta Mountains. Millennial-scale variations in the hematite content of Bear Lake sediments during the last glacial maximum (zone II) resemble Dansgaard-Oeschger (D-O) oscillations and Heinrich events (within dating uncertainties), suggesting that the influence of millennial-scale climate oscillations can extend beyond the North Atlantic and influence climate of the Great Basin. The magnetic mineralogy of zones IV-VII (MIS 5, 6, and 7

  5. Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

    Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei


    Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province.

  6. Optical dating of fluvio-deltaic clastic lake-fill sediments - A feasibility study in the Holocene Rhine delta (western Netherlands)

    Wallinga, J.; Bos, I.J.


    We test the applicability of quartz optically stimulated luminescence (OSL) dating on clastic lake sediments to investigate whether this dating method can be applied to study the timing and rate of deposition in Holocene fluvio-deltaic lakes. Our study concerns the filling of a lake by the Angstel-V

  7. Lake Towuti, Indonesia: First Sedimentological Results of a New Surface Sediment Study during the Icdp-Tdp Campaign 2015

    Hasberg, A. K.; Melles, M.; Vogel, H.; Russel, J.; Bijaksana, S.


    A. HASBERG1, M. MELLES1, H. VOGEL2, J. RUSSEL3, S. BIJAKSANA4 and all ICDP field campaign participations 1Institute for Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50974 Cologne, Germany, email: 2Department for Geology, University Bern, Switzerland3Department of Geology, Brown University, USA 4Faculty of Mining and Petroleum Engineering, Institute Teknologi Bandung, Indonesia Lake Towuti (2.75°S, 121.5°E), the largest tectonically formed lake (surface area: 561 km²) of the Republic Indonesia, is located in Central Sulawesi. The lake has a high, unique, Fe-reducing bacterial biodiversity and it has an important relevance to evolutionary biology through its location. Furthermore it is part of the Malili lake system, which consists of five lakes. The three largest of these, Matano, Mahalona and Towuti, are connected through a surface outflow today, but the linkage may not have always existed during the past, as indicated by the high level of endemism in each lake and the active tectonic movement of the 'Matano Fault system'. In summer 2015 the ICDP-funded Towuti Drilling Project (TDP) was conducted at Lake Towuti and recovered over 1000 meters of new sediment core. Within the scope of the TDP, lake surface sediments were also collected to investigate the modern terrestrial climate and aquatic environmental conditions, as well as the major sediment input sources from the catchment area. We collected a 1 to 4 km high-resolution grid of 84 surface samples from Lake Towuti and five samples from the Mahalona River, which links the Malili Lakes. These 89 surface samples were analyzed by various, sedimentological methods including smear-slide microscopy, coarse-fraction analyses, grain-size analysis, XRF-powder, and CNS measurements. The results will help to understand the interaction between the present-day lake sedimentation, hydrological and climatic conditions and to evaluate these as proxies for the hydrological

  8. Optimization of an effective extraction procedure for the analysis of microcystins in soils and lake sediments

    Chen Wei [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Li Lin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Gan Nanqin [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China); Song Lirong [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072 (China)]. E-mail:


    Microcystin analysis in sediments and soils is considered very difficult due to low recovery for extraction. This is the primary limiting factor for understanding the fate of toxins in the interface between water and sediment in both the aquatic ecosystem as well as in soils. In the present study, a wide range of extraction solvents were evaluated over a wide range of pH, extraction approaches and equilibration time to optimize an effective extraction procedure for the analysis of microcystins in soils and lake sediments. The number of extractions required and acids in extraction solutions were also studied. In this procedure, EDTA-sodium pyrophosphate solution was selected as an extraction solvent based on the adsorption mechanism study. The optimized procedure proved to be highly efficient and achieved over 90% recovery. Finally, the developed procedure was applied to field soil and sediment sample collected from Chinese lakes during bloom seasons and microcystins were determined in six of ten samples. - Efficiency of extraction of microcystins from soil and sediment was greatly increased.

  9. Near east paleomagnetic secular variation recorded in sediments from the Sea of Galilee (Lake Kinneret)

    Thompson, R.; Turner, G. M.; Stiller, M.; Kaufman, A.


    Paleomagnetic records of declination and inclination from sediments recovered from the bed of Lake Kinneret (32.4°N, 35.7°E) have been dated by radiocarbon techniques. The sediments span the last 5000 yr. The changes in inclination down the sediment cores are more pronounced than the declination fluctuations and are repeatable between the three coring sites, which are several kilometers apart. Magnetic susceptibility logs display 13 maxima in the 5-m-long sequences, with a pronounced susceptibility minimum about 1000 yr B.P. Many of the susceptibility maxima and minima can be easily correlated between coring sites and are shown to be dominantly related to changes in sediment carbonate content. The natural remanent magnetization intensity follows a similar pattern to that of susceptibility, and the natural remanence of the Kinneret sediments is presumed to reside in detrital magnetite grains carried into the lake by the river Jordan from the basalt-rich bedrock of the rift floor and the Golan Heights. The 14C chronology is strongly supported by a pollen study in which pronounced changes in the proportion of olive pollen were interpreted as being due to extensive cultivation of olives around Galilee in the Hellenistic and Byzantine periods. The Kinneret paleosecular variation records, if accurately dated, point to a complex spatial pattern of Holocene secular variation with significant variations over distances as small as 1000-2000 km.

  10. Contamination and risk assessment of heavy metals in bottom sediments from Lake Valencia, Venezuela

    González A.


    Full Text Available The contamination and risk assessment of heavy metals in the bottom sediments of the Lake Valencia, Venezuela, was performed by determining the Enrichment Factor (EF, the Geoaccumulation Factor (Igeo, the availability of metals and the Risk Index Code (RAC. The sediments were anthropogenic ally enriched with Pb, Zn, Cu and Cr and classified as uncontaminated to moderately contaminated, with a medium risk of Zn, Co, Ni and Cr, and low risk of Cu, Pb and Cd. Analysis of correlations and PCA showed temporal variations in the concentration of metals in the sediments during the rainy season, and spatial variations, where the depth and anthropogenic inputs are the main variables. The contamination of sediments was located on the axis connecting the mouths of the river Guayos, which crosses the city of Valencia, and the river Güey which crosses the city of Maracay, both highly industrialized. Although the concentration of dissolved heavy metals into the waters was within the regulations, important concentrations of Pb and Hg and the bioaccumulation of Hg and Cr, determined by the Bioconcentration Factor (BCF, were found in the fish tissues which indicate that the metal enrichment of the lake sediments is affecting the biota.

  11. Aspects of the bottom sediment of Lake Nakaumi and Honjo area ~ featuring with organic matter and the Sulfides ~

    Shinohara, R.


    Lake Nakaumi is a brackish water located at southwest Japan. Seawater from the Sea of Japan inflows through Sakai-strait, and river water flows through the Oohashi River into this lake. Lake Nakaumi is characterized with hypoxic and/or anoxic condition of bottom water derived with the distinct stratification of salinity in summer season. In this lake, a public project had been carried out for land reclamation since 1963. Honjo Area located to the north part of Lake Nakaumi, was semi-separated from Lake Nakaumi by reclamation dikes constructed for this project at 1981. However, this public project was aborted with the change of social conditions. To the effective utilization of the area, the partial removal of dike was carried out. Seawater from Sakai-strait flows directly into Honjo Area again. Environmental change of the lake is expected by this inflow of the seawater in Lake Nakaumi and Honjo Area after this restoration. It is well known that the surface sediment reflects the environment of lake bottom. The organic matter and the sulfides in sediment are good indicators of sedimentation environment. In this study, we analyzed them by several methods and grasped the bottom environment of both areas after the removal of dikes. We examined the impact of the restoration to both areas by comparing the observations with the past data. Surface sediment samples in Lake Nakaumi and Honjo Area were obtained at 77 and 40 stations, respectively. We collected surface sediment (about 1cm) were for each station, and analyzed total organic carbon (TOC) and total nitrogen (TN) as organic matter, and hydrogen sulfide (H2S) in pore water, total sulfide (TS) and acid volatile sulfide (AVS) as sulfides. TOC contents of Lake Nakaumi and Honjo Area range within 0.0-5.1% and 0.2-4.9%, respectively. TN contents range within 0.0-0.6 % and 0.1-0.6 %. TS contents range within 0.1-2.6% and 0.0-2.0 %. H2S contents range within 0.3-119.0 ppm and 0.5-140.4 ppm. AVS contents range within 0

  12. Holocene climate change in Newfoundland reconstructed using oxygen isotope analysis of lake sediment cores

    Finkenbinder, Matthew S.; Abbott, Mark B.; Steinman, Byron A.


    Carbonate minerals that precipitate from open-basin lakes can provide archives of past variations in the oxygen isotopic composition of precipitation (δ18Oppt). Holocene δ18Oppt records from the circum- North Atlantic region exhibit large fluctuations during times of rapid ice sheet deglaciation, followed by more stable conditions when interglacial boundary conditions were achieved. However, the timing, magnitude, and climatic controls on century to millennial-scale variations in δ18Oppt in northeastern North America are unclear principally because of a dearth of paleo-proxy data. Here we present a lacustrine sediment oxygen isotope (δ18O) record spanning 10,200 to 1200 calendar years before present (cal yr BP) from Cheeseman Lake, a small, alkaline, hydrologically open lake basin located in west-central Newfoundland, Canada. Stable isotope data from regional lakes, rivers, and precipitation indicate that Cheeseman Lake water δ18O values are consistent with the isotopic composition of inflowing meteoric water. In light of the open-basin hydrology and relatively short water residence time of the lake, we interpret down-core variations in calcite oxygen isotope (δ18Ocal) values to primarily reflect changes in δ18Oppt and atmospheric temperature, although other factors such as changes in the seasonality of precipitation may be a minor influence. We conducted a series of climate sensitivity simulations with a lake hydrologic and isotope mass balance model to investigate theoretical lake water δ18O responses to climate change. Results from these experiments suggest that Cheeseman Lake δ18O values are primarily controlled by temperature and to a much lesser extent, the seasonality of precipitation. Increasing and more positive δ18Ocal values between 10,200 and 8000 cal yr BP are interpreted to reflect the waning influence of the Laurentide Ice Sheet on atmospheric circulation, warming temperatures, and rapidly changing surface ocean δ18O from the input of

  13. (210)Pb and compositional data of sediments from Rondonian lakes, Madeira River basin, Brazil.

    Bonotto, Daniel Marcos; Vergotti, Marcelo


    Gold exploration has been intensive in Brazilian Amazon over the last 40 years, where the use of mercury as an amalgam has caused abnormal Hg concentrations in water bodies. Special attention has been directed to Madeira River due to fact it is a major tributary of Amazon River and that since 1986, gold exploration has been officially permitted along a 350km sector of the river. The (21)(0)Pb method has been used to date sediments taken from nine lakes situated in Madeira River basin, Rondônia State, and to verify where anthropogenic Hg might exist due to gold exploitation in Madeira River. Activity profiles of excess (21)(0)Pb determined in the sediment cores provided a means to evaluate the sedimentation rates using a Constant Flux: Constant Sedimentation (CF:CS) and Constant Rate of Supply (CRS) of unsupported/excess (21)(0)Pb models. A significant relationship was found between the CF:CS sedimentation rates and the mean values of the CRS sedimentation rates (Pearson correlation coefficient r=0.59). Chemical data were also determined in the sediments for identifying possible relationships with Hg occurring in the area. Significant values were found in statistical correlation tests realized among the Hg, major oxides and Total Organic Carbon (TOC) content in the sediments. The TOC increased in the sediment cores accompanied by a loss on ignition (LOI) increment, whereas silica decreased following a specific surface area raising associated to the TOC increase. The CRS model always provided ages within the permitted range of the (21)(0)Pb-method in the studied lakes, whereas the CF:CS model predicted two values above 140 years. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. In-situ characterization and assessment of arsenic mobility in lake sediments.

    Sun, Qin; Ding, Shiming; Wang, Yan; Xu, Lv; Wang, Dan; Chen, Jing; Zhang, Chaosheng


    In-situ characterization and assessment of arsenic (As) mobility in sediments was scarce. In this study, the distributions of labile As at a vertical resolution of 2 mm were obtained in the sediments of a large Lake Taihu through in-situ measurements using a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The DGT-labile As, interpreted as DGT flux (FDGT), exhibited three different patterns in the lake, with all the patterns generally showing an increasing mobility followed by a decreasing mobility with sediment depth. The mobility of As could be characterized by the average FDGT (0.06-1.27 pg cm(-2) s(-1)) in the top 10 mm surface sediments, the maximal FDGT (FDGT-M, 0.14-2.44 pg cm(-2) s(-1)) in the end of the initial increasing phase of FDGT, and the diffusion length (ΔL, 28-66 mm) from the depth showing the FDGT-M to the sediment-water interface. The upward mobilization of labile As from the deep sediments to the surface sediments and overlying water became evident when FDGT-M > 1.7 pg cm(-2) s(-1) or ΔL mobility of As in the upper sediments was controlled by the reduction of As(V) and the reductive dissolution of Fe(III) (hydr)oxides, while the decreasing mobility in the deep sediments was attributed to immobilization of As(III) by secondary Fe(II)-bearing minerals.

  15. Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China

    Zhijian LI; Qinyan YUE; Baoyu GAO; Yanwen WANG; Qing LIU


    The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration (EPCo) and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second- order rate equation, but more appropriate to the pseudo- second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus (SRP) sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC0 and SRP of water, the status (adsorption, releasing or in equilibrium) of sediment phosphorus could be determined. The sediments at site S l, S3, S4, S5, and S7 where the EPC0s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S 12, where the EPC0s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phos- phorus can be a secondary pollution source in downstream Nansi Lake.

  16. Differences in the Composition of Archaeal Communities in Sediments from Contrasting Zones of Lake Taihu

    Fan, Xianfang; Xing, Peng


    In shallow lakes, different primary producers might impact the physiochemical characteristics of the sediment and the associated microbial communities. Until now, little was known about the features of sediment Archaea and their variation across different primary producer-dominated ecosystems. Lake Taihu provides a suitable study area with cyanobacteria- and macrophyte-dominated zones co-occurring in one ecosystem. The composition of the sediment archaeal community was assessed using 16S rRNA gene amplicon sequencing technology, based on which the potential variation with respect to the physiochemical characteristics of the sediment was analyzed. Euryarchaeota (30.19% of total archaeal sequences) and Bathyarchaeota (28.00%) were the two most abundant phyla, followed by Crenarchaeota (11.37%), Aigarchaeota (10.24%) and Thaumarchaeota (5.98%). The differences found in the composition of the archaeal communities between the two zones was significant (p = 0.005). Sediment from macrophyte-dominated zones had high TOC and TN content and an abundance of archaeal lineages potentially involved in the degradation of complex organic compounds, such as the order Thermoplasmatales. In the area dominated by Cyanobacteria, archaeal lineages related to sulfur metabolism, for example, Sulfolobales and Desulfurococcales, were significantly enriched. Among Bathyarchaeota, subgroups MCG-6 and MCG-15 were significantly accumulated in the sediment of areas dominated by macrophytes whereas MCG-4 was consistently dominant in both type of sediments. The present study contributes to the knowledge of sediment archaeal communities with different primary producers and their possible biogeochemical functions in sediment habitats. PMID:27708641

  17. Great Lakes

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.


    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  18. Episodes of low dissolved oxygen indicated by ostracodes and sediment geochemistry at Crystal Lake, Illinois, USA

    Curry, B. Brandon; Filippelli, G.M.


    Low dissolved oxygen during the summer and early fall controls profundal continental ostracode distribution in Crystal Lake (McHenry County), Illinois, favoring Cypria ophthalmica and Physocypria globula at water depths from 6 to 13 m. These species also thrived in the lake's profundal zone from 14,165 to 9600 calendar year before present (cal yr b.p.) during the late Boiling, Allerod, and Younger Dryas chronozones, and early Holocene. Characterized by sand, cemented tubules, large aquatic gastropod shells, and littoral ostracode valves, thin (1-6 cm) tempestite deposits punctuate thicker deposits of organic gyttja from 16,080 to 11,900 cal yr b.p. The succeeding 2300 yr (11,900-9600 cal yr b.p.) lack tempestites, and reconstructed water depths were at their maximum. Deposition of marl under relatively well-oxygenated conditions occurred during the remainder of the Holocene until the arrival of Europeans, when the lake returned to a pattern of seasonally low dissolved oxygen. Such conditions are also indicated in the lake sediment by the speciation of phosphorus, high concentrations of organic carbon, and abundant iron and manganese occluded to mineral grains. Initial low dissolved oxygen was probably caused by the delivery of dissolved P and Fe in shallow groundwater, the chemistry of which was influenced by Spodosol pedogenesis under a spruce forest. The triggering may have been regionally warm and wet conditions associated with retreat of the Lake Michigan lobe (south-central Laurentide Ice Sheet). ?? 2010, by the American Society of Limnology and Oceanography Inc.

  19. Occurrence of antibiotics in water, sediments, aquatic plants, and animals from Baiyangdian Lake in North China.

    Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi


    This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotics in the water (0.86-1563 ng L(-1)), while quinolones were prominent in sediments (65.5-1166 μg kg(-1)) and aquatic plants (8.37-6532 μg kg(-1)). Quinolones (17.8-167 μg kg(-1)) and macrolides [from below detection limit (BDL) to 182 μg kg(-1)] were often found in aquatic animals and birds. Salvinia natans exhibited the highest bioaccumulation capability for quinolones among three species of aquatic plants. Geographical differences of antibiotic concentrations were greatly due to anthropogenic activities. Sewage discharged from Baoding City was likely the main source of antibiotics in the lake. Risk assessment of antibiotics on aquatic organisms suggested that algae and aquatic plants might be at risk in surface water, while animals were likely not at risk.

  20. Forsmark site investigation. Investigation of marine and lacustrine sediment in lakes. Field data 2003

    Hedenstroem, Anna [SGU, Uppsala (Sweden)


    The aim of this activity is to describe the aerial and stratigraphical distribution of marine and lacustrine sediment i.e. sediment overlaying the glacial till and/or bedrock surface, in lakes in the Forsmark area. The investigation is carried out within areas where mapping of unconsolidated Quaternary deposits is presently carried out. Since small and shallow lakes cover a large part of the region, this work will give important information on the distribution and stratigraphy of sedimentary deposits not included in the regular mapping of unconsolidated Quaternary deposits within the site investigation programme. Samples were also collected for laboratory analyses of grain size distribution, mineralogical composition as well as the total content of C, N and S and calcium carbonate. The analyses will be carried out on selected samples of representative sedimentary units in order to characterise the chemical and physical properties of the unconsolidated deposits. The analytical data will be useful for the hydrogeological modelling and for models of the Quaternary evolution of the area. The mineralogical analyses of clay may provide information on the origin of the clay particles. One stratigraphic sequence from Lake Eckarfjaerden will be stored for later analyses, e.g. pollen analysis. This report includes field data from spring 2003. Together, the field data and the forthcoming results from the laboratory analyses will form the basis for construction of stratigraphical profiles to be presented in a following report in the fall 2003.


    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  2. A comparative study of ancient environmental DNA to pollen and macrofossils from lake sediments reveals taxonomic overlap and additional plant taxa

    Pedersen, M.W.; Ginolhac, A.; Orlando, L.


    We use 2nd generation sequencing technology on sedimentary ancient DNA (. sedaDNA) from a lake in South Greenland to reconstruct the local floristic history around a low-arctic lake and compare the results with those previously obtained from pollen and macrofossils in the same lake. Thirty...... and Asparagaceae) are absent from the pollen and macrofossil records. An age model for the sediment based on twelve radiocarbon dates establishes a chronology and shows that the lake record dates back to 10,650calyrBP. Our results suggest that sedaDNA analysis from lake sediments, although taxonomically less...

  3. Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events: examples of lacustrine varved sediments in Japan

    Ishihara, Yoshiro; Sasaki, Yasunori; Sasaki, Hana; Onishi, Yuri


    Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events are frequently intercalated in lacustrine successions. When sediment gravity flow deposits are present in varved sediments, it is suggested that they provide valuable information about sediment gravity flows, because they can easily trace laterally and can give the magnitude of erosion and recurrence interval of events. In addition, because large sedimentary bodies of stacked sediment gravity flow deposits in varved sediments of a calm lake are not suggested, a relatively simple depositional environment is expected. In the present study, we analysed sedimentary facies of sediment gravity flow deposits in varved lacustrine diatomites in the Middle Pleistocene Hiruzenbara and Miyajima formations in Japan, and concluded a depositional model of the lacustrine sediment gravity flow deposits. Varved diatomites: The Hiruzenbara Fm., a dammed lake fill as foots of Hiruzen Volcanos, is deposited during an interglacial period during MIS12 to 15. Varves of ca. 8000 yr were measured in a 20 m intercalating flood and lake slope failure-induced sediment gravity flow deposits. The Miyajima Fm., distributed in a paleo-caldera lake in NE Japan, includes many sediment gravity flow deposits possibly originated from fandeltas around the lake. These formations have differences in their depositional setting; the Hiruzebara Fm. was deposited in a large lake basin, whereas the Miyajima Fm. was deposited in a relatively small basin. Because of the depositional setting, intercalation of volcaniclastics is dominant in the Miyajima Fm. Lacustrine sediment gravity flow deposits: Sediment gravity flow deposits in both formations can be classified into flood- and lake slope failure-induced types based on the sedimentary facies. Composites of the both types are also found. Flood-induced types comprise fine-grained silts dominated by carbonaceous fragments, whereas lake slope failure-induced types are

  4. Sedimentary Bacteriopheophytin a as an indicator of meromixis in varved lake sediments of Lake Jaczno, north-east Poland, CE 1891-2010

    Butz, Christoph; Grosjean, Martin; Poraj-Górska, Anna; Enters, Dirk; Tylmann, Wojciech


    Trends in eutrophication and meromixis pose serious threats to water quality and biodiversity in freshwater ecosystems around the world. Because long-term observational data rarely exist, it is very difficult to assess whether meromixis is the result of anthropogenic impacts, climate variability, natural ecosystem development or a combination of these factors. Lake sediment proxy-data may help understand how and why eutrophication and meromixis occurred and disappeared in the past. In this study, we present a novel method and proxy to investigate past episodes of meromixis and hypolimnetic anoxia recorded in lake sediments. We use high-resolution (70 × 70 μm/pixel) calibrated hyperspectral imaging of a varved lake sediment core from meromictic Lake Jaczno (north-east Poland), to quantitatively map the spatial distribution of Bacteriopheophytin a (Bphe a) at very high sub-varve (i.e. seasonal) resolution. Bphe a is a bacterial pigment and stable degradation product of Bacteriochlorophyll a (Bchl a), which is produced by anoxygenic phototrophic bacteria (APBs) at the chemocline of meromictic lakes. Using sedimentary Bphe a we infer episodes of meromixis (i.e. long-term hypolimnetic anoxia) and changing mixing conditions (i.e. seasonal temperature, event-based water mixing) for the past ca. 120 years. Absence of meromixis occurred on several occasions. From the beginning of our record in CE 1891 until ca. CE 1918, meromixis was not observed. During this time, green pigments (mainly chlorophyll a [Chl a] and diagenetic products) produced by phototrophic algae were deposited while Bphe a was absent. This suggests that regular lake overturning prevented the formation of a persistent chemocline. Bphe a was identified before CE 1890 (Butz et al. 2015), but over the studied period 1891-2011, meromixis was established in CE 1918 and generally persisted through modern times. However, short-term interruptions of the chemocline were observed following events of rapid

  5. Effects of bioirrigation of non-biting midges (Diptera: Chironomidae) on lake sediment respiration

    Baranov, Viktor; Lewandowski, Jörg; Romeijn, Paul; Singer, Gabriel; Krause, Stefan


    Bioirrigation or the transport of fluids into the sediment matrix due to the activities of organisms such as bloodworms (larvae of Diptera, Chironomidae), has substantial impacts on sediment respiration in lakes. However, previous quantifications of bioirrigation impacts of Chironomidae have been limited by technical challenges such as the difficulty to separate faunal and bacterial respiration. This paper describes a novel method based on the bioreactive tracer resazurin for measuring respiration in-situ in non-sealed systems with constant oxygen supply. Applying this new method in microcosm experiments revealed that bioirrigation enhanced sediment respiration by up to 2.5 times. The new method is yielding lower oxygen consumption than previously reported, as it is only sensitive to aerobic heterotrophous respiration and not to other processes causing oxygen decrease. Hence it decouples the quantification of respiration of animals and inorganic oxygen consumption from microbe respiration in sediment.

  6. Lake restoration with aluminium, bentonite and Phoslock: the effect on sediment stability and light attenuation

    Egemose, Sara; Reitzel, Kasper; Flindt, Mogens

    treatments on aluminium mobility, sediment stability or light climate. A laboratory flume experiment including three shallow Danish lakes was conducted. We measured the effects of aluminium, Phoslock (a commercial product), bentonite, and a combination of bentonite/aluminium. Each treatment caused a varying...... consolidation of the sediment. The largest consolidation occurred using Phoslock- and bentonite-addition followed by bentonite/aluminium-addition, whereas aluminium alone had no effect. Sediment stability thresholds were measured before and after addition. Especially Phoslock, but also bentonite and bentonite....../aluminium increased sediment erosion threshold, with respectively 200%, 43% and 57%. Aluminium, bentonite/aluminium, and Phoslock improved the light conditions in the water phase, with respectively 60%, 57% and 50%, whereas bentonite created higher turbidity. Conclusively aluminium improved the light conditions...

  7. Triclosan and Hydroxylated Polybrominated Diphenyl Ethers in Lake and Esturaine Sediments

    Arnold, W. A.; Kerrigan, J. F.; McNeill, K.; Erickson, P. R.; Grandbois, M.


    Halogenated diphenyl ethers are a class of emerging contaminants that includes the antibacterial compound triclosan and the flame retardant polybrominated diphenyl ethers (PBDEs). Both triclosan and hydroxylated polybrominated diphenyl ethers (OH-BDEs) are known to form dioxins when exposed to sunlight in aqueous solution. Thus, it is important to understand the sources and presence of these compounds in the environment, especially because OH-BDEs are breakdown products of PBDEs and also naturally produced compounds. In this work, the levels of OH-BDEs were determined in lake sediments from Minnesota and esturaine sediments from San Francisco Bay. Both surface sediments over a broad spatial area and sediment cores were collected and analyzed. Triclosan was used as a marker of wastewater as a source of the targeted emerging contaminants. The relationship between triclosan and OH-BDE levels provides insight into the importance of natural and anthropogenic influences on the levels of OH-BDEs.

  8. Situation of sewage input reflected by nitrogen isotopic composition in a sediment core of Hongfeng Lake


    Nitrogen in Hongfeng South Lake water mainly comes from sewage with high N concentrations from Pingba Chemical Fertilizer Plant (PCFP). Studies on the sediment core HF010427 sampled in the lake showed that the upward increase of nitrogen isotopic composition of sedimentary organic nitrogen (δ15Norg) accorded with the trend of industrial total production (TP) of PCFC. On the contrary, diagenesis will theoretically cause an upward decrease of δ15Norg. Because no treatment of sewage water was carried out, TP corresponds with sewage emission, indicating that sedimentary δ15Norg can reflect well the total trend of sewage input. The very similar profile shape between nitrogen isotopic composition of sedimentary absorbed ammonium (δ15NH4+absorbed) and TP of PCFP suggests that δ15NH4+absorbed can be used to reconstruct more detailed situation of sewage input. The study has a reference to history investigation of sewage input.

  9. Carbon isotope evidence for diurnal variations in methanogenesis in freshwater lake sediments

    Jedrysek, Mariusz Orion


    Diurnal variations in the 13C/12C ratio in bubble methane have been observed in shallow water lake sediments at Lake Piaseczno, Poland. Measurements in August 1993 and September 1992 show that values are lowest in the early morning, and highest in the afternoon, ranging from a minimum of -63.1 at 03:30 on August 30, 1993 to a maximum of -47.5 at 15:30 on August 29, 1993. The minimum values were apparently caused by an enhanced CO 2H 2 methanogenesis pathway. The maximum values occur when the CO 2 pool decreases and acetic acid fermentation becomes relatively more important. Seasonal variation and seasonal variations in the magnitude of the diurnal variations in the δ 13CH 4 value may depend on temperature and the day-to-night time ratio, of the diurnal cycle.

  10. Diatom assemblages and quantitative reconstruction for paleosalinity from a sediment core of Chencuo Lake,southern Tibet

    YANG; Xiangdong; WANG; Sumin; C.Kamenik; R.Schmidt; SHEN


    Combining with the diatom-based conductivity transfer function from Qinghai-Xizang (Tibetan) Plateau lakes, the lake salinity for the past 300 years was quantitatively reconstructed based on the analysis of diatom assemblages from a sediment core in Chencuo Lake, southern Tibet. The distinct negative relationship between inferred conductivity and recorded lakelevels in recent years suggests that the lake salinity can reflect the fluctuations of effective moisture of climate in lake area. The salinity inferred from diatoms reveals several major hydrological episodes. An obvious desalination of lake water occurred during the last cold interval of the Little Ice Age (about 1845-1885 AD), indicating a cold and moist climate. The lake salinity presented a rapid increase trend since the middle 1960s, with a peak value and high amplitude of salinity variability in the whole past 300 years. The low effective moisture inferred from the lake salinity may have contributed to the enhanced evaporation by the continuous increase of temperature in recent years.

  11. DNA from lake sediments reveals the long-term dynamics and diversity of Synechococcus assemblages

    I. Domaizon


    Full Text Available While picocyanobacteria (PC are important actors in carbon and nutrient cycles in aquatic systems, factors controlling their interannual dynamics and diversity are poorly known due to the general lack of long-term monitoring surveys. This study intended to fill this gap by applying a DNA-based paleolimnological approach to sediment records from a deep subalpine lake that has experienced dramatic changes in environmental conditions during the last century (eutrophication, re-oligotrophication and large-scale climate changes. In particular, we investigated the long-term (100 yr diversity and dynamics of Synechococcus,, PC that have presumably been affected by both the lake trophic status changes and global warming. The lake's morphological and environmental conditions provided the ideal conditions for DNA preservation in the sediment archives. Generalised additive models applied to quantitative PCR (qPCR; quantitative Polymerase Chain Reaction results highlighted that an increase in summer temperature could have a significant positive impact on the relative abundance of Synechococcus, (fraction of Synechococcus, in total cyanobacteria. The diversity of Synechococcus, in Lake Bourget was studied by phylogenetic analyses of the 16S rRNA gene and the following internally transcribed spacer (ITS. Up to 23 different OTUs (based on 16S rRNA, which fell into various cosmopolitan or endemic clusters, were identified in samples from the past 100 yr. Moreover, the study of ITS revealed a higher diversity within the major 16S rRNA-defined OTUs. Changes in PC diversity were related to the lake's trophic status. Overall, qPCR and sequencing results showed that environmental changes (in temperature and phosphorus concentration affected Synechococcus, community dynamics and structure, translating into changes in genotype composition. These results also helped to re-evaluate the geographical distribution of some Synechococcus, clusters. Providing such novel

  12. Source apportionment of sediment-associated aliphatic hydrocarbon in a eutrophicated shallow lake, China.

    Wang, Ji-Zhong; Yang, Ze-Yu; Chen, Tian-Hu


    Chaohu Lake, one of the most eutrophicated lakes in China, has been suffering from long-term outside pollution, urban sewage, river outflows, and agricultural runoff which expectedly have been the main contributors of hydrocarbons. However, the contributions from these various sources have not been specified. The present study is aimed at identifying the potential sources of hydrocarbons in surface sediment around the whole lake and assessing the relative contributions using principal components analysis-multiple linear regression (PCA-MLR). Sixty-one surface sediments covering the whole Chaohu Lake and three main estuaries of inflowing rivers were collected, dried, extracted, and analyzed for 27 normal alkanes (n-alkanes, from C(12) to C(38), defined Σ(27)AH) and unresolved complex mixture (UCM) by GC/MS. Diagnostic ratios and PCA-MLR were utilized to apportion their sources. The concentrations of Σ(27)AH and UCM ranged from 434 to 3,870 ng/g and 11.9 to 325 μg/g dry weight, respectively, for all samples. The concentrations of Σ(27)AH in western region and estuary of Nanfei River were slightly higher but without statistical significance than those from eastern region and estuaries of Yuxi River and Hangbu River. The concentration of UCM from western region was significantly higher than that obtained from eastern region. These results reflect the importance of input of urban runoff by Nanfei River and serious eutrophication in western region. Aliphatic hydrocarbons in Chaohu Lake were mainly derived from high plant wax with mixed sources of phytoplankton and petroleum. Weak microbial decomposition of n-alkanes would be expected to occur from the low ratios of isoprenoid hydrocarbons pristine (pri) and phytane (phy) to n-C(17) and n-C(18), respectively. Higher plant, fossil combustion, petroleum residue, and phytoplankton were proposed as the main origines of aliphatic hydrocarbons by PCA while the contributions of individual n-alkane homologues, pri and phy

  13. Yellowstone Lake Nanoarchaeota

    Scott eClingenpeel


    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  14. Yellowstone lake nanoarchaeota.

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P; Nealson, Kenneth; McDermott, Timothy R


    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  15. Geochronology of recent lake sediments from Longgan Lake,middle reach of the Yangtze River,influenced by disturbance of human activities


    The impacts of human activities in Longgan Lake region on the distribution of 210Pb in lake sediment made it difficult to establish geochronological sequence. However, environmental proxies recorded these human activities and could be used as time marker to check 210Pb dating results. Based on the analysis of 210Pbexc distribution in cores LS-1 and LGL-1, and in combination with the human activities records in grain-size and element concentration, the sedimentation rates in the upper layers of these two cores were determined to be 0.19 and 0.23 cm/a respectively. The MAR (mass accumulation rates) of these two cores demonstrated that natural condition, such as precipitation and runoffs, led to the variation of MAR before human disturbance, and human activities controlled the sedimentary processes afterwards, which obviously reduced the particles influx into the lakes. During 1940s when human activity had not changed the water system within the catchment, 210Pb activity was abnormally strong in lakes along middle to lower reaches of the Yangtze River, which might be attributed to less precipitation and can be used as a time marker for geochronological research.

  16. Sediment baseline study of levels and sources of polycyclic aromatic hydrocarbons and heavy metals in Lake Nicaragua

    Scheibye, Katrine; Weisser, Johan; Borggaard, Ole K.;


    Selected metals and polycyclic aromatic hydrocarbons (PAHs) were analyzed in sediment samples from 24 sites in Lake Nicaragua sampled May 2010 to provide a baseline of pollution levels. Cu exceeded the Consensus-Based Sediment Quality Guideline (CBSQG) Threshold Effect Concentrations (TECs) at 21...... showed that the CBSQG TECs were exceeded by naphthalene at five sites. The sum concentrations of the 16 US EPA priority PAHs (∑PAH16) ranged from 0.01mgkg(-1)dw to 0.64mgkg(-1)dw. The highest ∑PAH16 concentration was found upstream in River Mayales and the PAH composition revealed a heavy PAH fraction (e....... This study concluded that areas of Lake Nicaragua represent an important pollution baseline for future studies in this lake and other tropical lakes....

  17. Optimizing Standard Sequential Extraction Protocol With Lake And Ocean Sediments

    The environmental mobility/availability behavior of radionuclides in soils and sediments depends on their speciation. Experiments have been carried out to develop a simple but robust radionuclide sequential extraction method for identification of radionuclide partitioning in sed...

  18. Assessing sediment dynamics of the Middle St. Johns River Basin, Lake Jesup, Florida, USA

    Anderson, W. T.; Nielsen, S. M.; Scinto, L. J.; Thomas, S.; Fugate, D. C.; Corbett, D. R.; Brandt-Williams, S.


    Lake Jesup is a shallow, hypereutrophic lake located in the middle St. Johns River basin that received large loads of secondary effluent prior to 1985 and experiences tidal, tributary and wind influenced flow. To date we have assessed the use of several different types of sediment traps at different water depths within this shallow basin (typically less than 2.5 m). Each system deployed has its advantages, but deployments in shallow systems present unique challenges. We have augmented our sediment traps with additional observation and data collection systems to evaluate our approach for studying sedimentation rates in the basin. These systems include a floating barge platform to collect daily water samples for suspended particles, weather stations for wind direction and velocity current (flow) meter and acoustic Doppler water velocity systems (ADVs). Results from 2009 to 2010 show mass accumulation rates ranging between 200 g dw m-2 d-1 to 1200 g dw m-2 d-1. Trap material was analyzed for nutrients to better understand fluxes of carbon, nitrogen, and phosphorus. Sediment oxygen demand was measured during incubation experiments to determine potential effects on water column oxygen concentrations during resuspension events. In the second phase of this project (2010 to 2011) we will measure radioisotopes to better estimate the source of resuspended particles. Our goal is to use the deployed instrumentation to show how hydrodynamics affect sediment transport in this basin. Studying the sediment dynamics of highly productive fresh water end members of estuary systems is critical to better quantify biogeochemical fluxes necessary for effective restoration management. This paper will present a model of nutrient flux and accumulation rates, sediment oxygen demand, correlations between sediment flux and potential driving forces, and initial results from radioisotope sourcing.

  19. In Situ, High-Resolution Profiles of Labile Metals in Sediments of Lake Taihu

    Dan Wang


    Full Text Available Characterizing labile metal distribution and biogeochemical behavior in sediments is crucial for understanding their contamination characteristics in lakes, for which in situ, high-resolution data is scare. The diffusive gradient in thin films (DGT technique was used in-situ at five sites across Lake Taihu in the Yangtze River delta in China to characterize the distribution and mobility of eight labile metals (Fe, Mn, Zn, Ni, Cu, Pb, Co and Cd in sediments at a 3 mm spatial resolution. The results showed a great spatial heterogeneity in the distributions of redox-sensitive labile Fe, Mn and Co in sediments, while other metals had much less marked structure, except for downward decreases of labile Pb, Ni, Zn and Cu in the surface sediment layers. Similar distributions were found between labile Mn and Co and among labile Ni, Cu and Zn, reflecting a close link between their geochemical behaviors. The relative mobility, defined as the ratio of metals accumulated by DGT to the total contents in a volume of sediments with a thickness of 10 mm close to the surface of DGT probe, was the greatest for Mn and Cd, followed by Zn, Ni, Cu and Co, while Pb and Fe had the lowest mobility; this order generally agreed with that defined by the modified BCR approach. Further analyses showed that the downward increases of pH values in surface sediment layer may decrease the lability of Pb, Ni, Zn and Cu as detected by DGT, while the remobilization of redox-insensitive metals in deep sediment layer may relate to Mn cycling through sulphide coprecipitation, reflected by several corresponding minima between these metals and Mn. These in situ data provided the possibility for a deep insight into the mechanisms involved in the remobilization of metals in freshwater sediments.

  20. Clear Lake sediments: anthropogenic changes in physical sedimentology and magnetic response.

    Osleger, David A; Zierenberg, Robert A; Suchanek, Thomas H; Stoner, Joseph S; Morgan, Sally; Adam, David P


    We analyzed the sedimentological characteristics and magnetic properties of cores from the three basins of Clear Lake, California, USA, to assess the depositional response to a series of land use changes that occurred in the watershed over the 20th century. Results indicate that distinct and abrupt shifts in particle size, magnetic concentration/mineralogy, and redox conditions occur concurrently with a variety of ecological and chemical changes in lake bed sediments. This coincidence of events occurred around 1927, a datum determined by an abrupt increase in total mercury (Hg) in Clear Lake cores and the known initiation of open-pit Hg mining at the Sulphur Bank Mercury Mine, confirmed by 210Pb dating. Ages below the 1927 horizon were determined by accelerator mass spectrometry on 14C of coarse organic debris. Calculated sedimentation rates below the 1927 datum are approximately 1 mm/yr, whereas rates from 1927 to 2000 are up to an order of magnitude higher, with averages of approximately 3.5-19 mm/yr. In both the Oaks and Upper Arms, the post-1927 co-occurrence of abrupt shifts in magnetic signatures with color differences indicative of changing redox conditions is interpreted to reflect a more oxygenated diagenetic regime and rapid burial of sediment below the depth of sulfate diffusion. Post-1927 in the Oaks Arm, grain size exhibits a gradual coarsening-upward pattern that we attribute to the input of mechanically deposited waste rock related to open-pit mining activities at the mine. In contrast, grain size in the Upper Arm exhibits a gradational fining-upward after 1927 that we interpret as human-induced erosion of fine-grained soils and chemically weathered rocks of the Franciscan Assemblage by heavy earthmoving equipment associated with a road- and home-building boom, exacerbated by stream channel mining and wetlands destruction. The flux of fine-grained sediment into the Upper Arm increased the nutrient load to the lake, and that in turn catalyzed profuse

  1. Geochemistry and mineralogy approaches to characterize brick and its lake sediments sources: Antioch Roman City (Southern Turkey)

    El Ouahabi, Meriam; Hubert, Aurelia; Benjelloun, Yacine; Chene, Grégoire; Strivay, David; De Sigoyer, Julia; Pamir, Hatice; Karabacak, Volkan; Fagel, Nathalie


    The Roman aqueduct of Antioch-on-the-Orontes (Southern Turkey) is situated close to the Antioch city. This last is located near the Amik Lake (Lake of Antioch) and close to the junction between the active Dead Sea fault and the East Anatolian fault. During the Roman period, the Amik Plain was more densely occupied than at any time in its history [1]. The study focuses on the bricks and the lake sediments characterization in order to determine the source area as well as the technical productio...

  2. Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

    Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.


    This report compares concentrations for a wide range of inorganic and organic constituents in bed sediment from Big Base Lake and Little Base Lake, which are located on Little Rock Air Force Base, Arkansas, to sediment-quality guidelines. This report also compares trace-metal concentrations in a bed-sediment core sample to sediment age to determine when the highest concentrations of trace metals were deposited in Big Base Lake.

  3. Reservoir Sediment Management Workshop for Tuttle Creek Lake and Perry Lake Reservoirs in the Kansas River Basin


    kick in the seat of the pants: Using your explorer, artist , judge, and warrior to be more creative. New York, NY: Harper and Row Publishers...accumulation. Neighboring Milford Lake could offer more supply yield with increased inflow. A technique to evaluate this approach is to perform a

  4. Sediment delivery and lake dynamics in a Mediterranean mountain watershed: Human-climate interactions during the last millennium (El Tobar Lake record, Iberian Range, Spain).

    Barreiro-Lostres, Fernando; Brown, Erik; Moreno, Ana; Morellón, Mario; Abbott, Mark; Hillman, Aubrey; Giralt, Santiago; Valero-Garcés, Blas


    Land degradation and soil erosion are key environmental problems in Mediterranean mountains characterized by a long history of human occupation and a strong variability of hydrological regimes. To assess recent trends and evaluate climatic and anthropogenic impacts in these highly human modified watersheds we apply an historical approach combining lake sediment core multi-proxy analyses and reconstructions of past land uses to El Tobar Lake watershed, located in the Iberian Range (Central Spain). Four main periods of increased sediment delivery have been identified in the 8m long sediment sequence by their depositional and geochemical signatures. They took place around 16th, late 18th, mid 19th and early 20th centuries as a result of large land uses changes such as forest clearing, farming and grazing during periods of increasing population. In this highly human-modified watershed, positive synergies between human impact and humid periods led to increased sediment delivery periods. During the last millennium, the lake depositional and geochemical cycles recovered quickly after each sediment delivery event, showing strong resilience of the lacustrine system to watershed disturbance. Recent changes are characterized by large hydrological affections since 1967 with the construction of a canal from a nearby reservoir and a decreased in anthropic pressure in the watershed as rural areas were abandoned. The increased fresh water influx to the lake has caused large biological changes, leading to stronger meromictic conditions and higher organic matter accumulation while terrigenous inputs have decreased. Degradation processes in Iberian Range watersheds are strongly controlled by anthropic activities (land use changes, soil erosion) but modulated by climate-related hydrological changes (water availability, flood and runoff frequency).


    QIAN Jin; ZHENG Sha-sha; WANG Pei-fang; WANG Chao


    Contaminants resuspension in sediments rnduced by wind-wave could influence the water quality in shallow lakes.Resuspension of surface sediments from the Zhushan Bay,Taihu Lake was simulated under different wind forcing by using a pneumatic annular flume in this study.Acoustic Doppler Velocimeter (ADV) was used to measure flow velocity at each wind speed,and the characteristics of sediment resuspension were studied with the layered sampling technology.The experimental results show that the flow velocity increases with wind speed obviously and 6m/s is a critical wind speed which affected hydrodynamic conditions significantly.The distribution of flow velocity and water depth is different from that in ordinary open channel.With the enhanced hydrodynamic factors,the Suspended Solids Concentration (SSC) in water increases accordingly,and the incipient velocity of sediment resuspension is about 0.21 rm/s.Based on the analysis of wind speed and average SSC in water column,the quantitative relationship is obtained.The SSC of the bottom layer is higher than the content of surface layer under different hydrodynamic conditions,and there are similar distributions between SSC and flow velocity in different water layers.

  6. [Characteristics and Risk Assessment of Heavy Metals in Core Sediments from Lakes of Tibet].

    Guo, Bi-xi; Liu, Yong-qin; Zhang, Fan; Hou, Ju-zhi; Zhang, Hong-bo


    To explore the source of heavy metals in lake sediments and their hazard to environment on Tibetan Plateau, China, heavy metal (Cu, Zn, Cd, Pb, Cr, Co, Ni and As) levels in surface sediments of 18 lakes were investigated. Inductively Coupled Plasma Mass Spectrometry (ICP-MS, X-7 series) was used to determine the contents of heavy metals and the concentrations of carbon and nitrogen in sediment samples were analyzed by element analyzer (Vario Max CN, Elementar, Germany). The average concentrations for Cu, Zn, Cd, Pb, Cr, Co, Ni and As were 24.61 mg x kg(-1), 70.14 mg x kg(-1), 0.26 mg x kg(-1), 25.43 mg x kg(-1), 74.12 mg x kg(-1), 7.93 mg x kg(-1), 33.85 mg x kg(-1), 77.69 mg x kg(-1). It was found that heavy-metal concentrations in Tibet sediments were higher than those in Antarctic, but lower than those in the regions affected by anthropogenic activities. The contents of Cu, Zn, Pb, Cr and Co in the samples were lower than the background values of Tibet. Correlation analysis and principal components analysis (PCA) were used to analyze the origins of heavy metals. The result showed that Cu, Zn, Cd, Pb, Co, Ni and As came from soil in drainage basin and atmospheric deposition. Cr was mainly affected by human activities. Assessment on ecological risk of heavy metals was carried out using Hakanson's method and cluster analysis (CA). Assessment on ecological risk indicated that Pumoyum Co, Longmo Co and Bangong Co were at low risks, Bieruoze Co was at high ecological risk level and the other lakes were at different risk levels.

  7. Processes and their explanatory factors governing distribution of organic phosphorous pools in lake sediments.

    Lü, Changwei; He, Jiang; Zuo, Le; Vogt, Rolf D; Zhu, Liang; Zhou, Bin; Mohr, Christian W; Guan, Rui; Wang, Weiying; Yan, Daohao


    The amount of organic phosphorus (OP) and its distribution among different pools in lake sediments depends on biotic and abiotic processes driving the OP fractionation. Key environmental factors governing these transformations processes between OP fractionations in sediments were studied on the basis of geochemical characteristics of OP pools in relation to environmental factors in the sediments. The results illustrate that the factors influencing the accumulation or depletion of different OP pools were intrinsically dependent on the composition of the deposited organic matter (OM). During the mineralization of the OM the microorganisms excrete the enzyme alkaline phosphatase, accelerating the OP hydrolysis, and thereby setting the grounds for the bacterially-mediated oxidation of OM. There are two main degradation products of the labile OP pool (LOP) and the moderately labile OP pool (MLOP): Either the OP is transformed to a dissolved organic or inorganic P form, and thereby released to water column, or OP is transformed to a non-labile OP pool and stored in the sediments. A comparative study showed that oxy-hydroxides of iron (Fe) and aluminum (Al) only played an important role in influencing OP fractionation in Lake Wuliangsuhai, while the complexation reactions of OP with calcium ions and sorption to its minerals are key factors governing the OP fractionation in the two alkaline lakes. It is worth noting that a significant correlation between the Fe-P pool and the pools of LOP and MLOP indicates that the degradation of the rather labile OP pools are highly dependent on the iron redox reaction.

  8. Characterizing Constituents of Sediment Phosphorus Fractionation in a Freshwater Shallow Lake System

    Xiao PU; Jing XIE; Hongguang CHENG; Shengtian YANG; Lu LU


    This study aimed to characterize constituents of phosphorus (P) fractionation as wel as reciprocities among factors in sediments of a freshwater shal ow lake. [Method] Surface sediment was discretely sampled at 24 sites through Van Veen grabs. Based on a modified sequential extraction scheme, P fractionation was determined as Fe/Al bound P (Fe/Al-P), Ca bound P (Ca-P), solute and re-ductive P (S/R-P) and organic P (OP). Curve estimation and Pearson product-mo-ment correlation were employed for statistical analysis. [Result] Total P (TP) content ranged from 443 to 774 mg/kg. Inorganic P (IP) was the major component of TP, of which Ca-P was dominated with an average of 51%±9.7%. Average contents of P fractionation were in the fol owing order: Ca-P(51%) > OP(29%) > S/R-P(8%) >Fe/Al-P(7%). The molar ratio of Fe to P was 11 - 20, close to the threshold value of P leaching. [Conclusion] In freshwater shal ow lakes, IP and Ca-P were prone to be relatively high, whereas Fe/Al-P was low compared with deep lakes. Occurrence of spatial y monotonic gradient indicated the primary causation of anthropogenic sources. Imminent sediment P liberation was also expected. Close associations a-mong TP, Fe/Al-P and Ca-P, implying that anthropogenic P was mainly bound to metals in particulates. Significant correlations of TOC and P fractionation highlighted endogenous mechanism and authigenic origin in sediments.

  9. Determination of the historical variation of the trophic state in lakes using sediment stratigraphies

    G. Olli


    Full Text Available Biogenic silica (BSi and phosphorous (P accumulation were investigated in sediment cores from Karlskärsviken, a bay of Lake Mälaren. The aim was to make use of BSi and P relations in sediment stratigraphies in order to investigate the historical nutrient trophy in a near shore lake environment since the Middle Ages, with focus on industrial times, and to evaluate anthropogenic influences on the bay's trophic state. The BSi accumulation in the sediments is a better indicator of former nutrient pelagic trophy than P accumulation in sediments and for this reason a BSi inferred P (BSi-P water concentration is calculated. This method enables the determination of the background total phosphorous (TP concentration (which is related to the reference conditions in the investigated bay; this background TP is determined equal to 0.020–0.022 mg L−1. There is an increasing trend of BSi-P concentration in the bay since the Middle Ages to the present, about 0.025 mg L−1, with a small decrease in the inner bay section during the last decades. The P accumulation rate is not found to have changed since the 1960s and 1970s, which indicates that the P loading to Karlskärsviken has not decreased. In Karlskärsviken, the shallow inner section of the bay, where the water quality is dominated by loading from the bay catchment area, is less nutritious than the water in the outer section, which is influenced by the main streams from the western part of Lake Mälaren.

  10. A bacterium capable of using phytol as its sole carbon source, isolated from algal sediment of Mud Lake, Florida.

    Hoag, K B; Bradley, W H; Tousimis, A J; Price, D L


    A species of Flavobacterium that consistently attacks pure phytol and can use it as a sole source of carbon has been isolated from the blue-green algal sediment of Mud Lake, Florida. Biochemical tests demonstrate that this bacterium also readily uses various other organic compounds. This bacterium may account for the degradation products of chlorophyll and its side chain phytol, which have been found in the Mud Lake algal sediment. Phytol and its degradation products play a role in Refsum's disease, but phytol is also the most promising precursor of the isoprenoid hydrocarbons found in oil shale of the Green River Formation (Eocene) of Colorado, Utah, and Wyoming. The discovery of this species of Flavobacterium is a significant product of a protracted study of the bacteriology, phycology, zoology, and geochemistry of the algal sediment forming in Mud Lake, which is believed to be a modern analogue of the kind of algal sediment that, through geologic time, became oil shale.

  11. Submersed Littoral Vegetation Distribution: Field Quantification and Experimental Analysis of Sediment Types from Onondaga Lake, New York


    and Methods 11 "• Typha latifolia L. (cattail) TL "* Sagittaria latifolia Willd. (arrowhead) SL The native species sago pondweed and water celery were...severely polluted body of water (Effler 1987). As a result of public health concerns related to the inflow of wastewater, Onondaga Lake was closed to...Nymphaea odorata, S. rigida, and T. latifolia all did poorly on Onondaga Lake sediments and/or water , and are not recommended for transplant efforts

  12. Is Lake Tahoe Terminal?

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.


    Lake Tahoe, an iconic ultra-oligotrophic lake in the central Sierra Nevada, has been studied intensively since 1968, with the goal of understanding and ultimately controlling its eutrophication and loss of clarity. Research on the lake has included a) periodic profiles of primary productivity, nutrients, temperature, and plankton; b) Secchi depth; c) nutrient limitation experiments; d) analysis of sediment cores; e) radiocarbon dating of underwater in-place tree stumps; g) analysis of long-term temperature trends. Work in its watershed has included a) monitoring of stream discharge, sediment and nutrients at up to 20 stream gaging stations; b) monitoring of urban runoff water quality at selected sites; c) development of a GIS data base, including soils, vegetation, and land use. Based on these studies, we know that a) primary productivity in the lake is limited by phosphorus, and continues to increase; b) the loss of clarity continues, but at a declining rate; c) the lake has been warming since 1970, and its resistance to deep mixing is increasing; d) historically the lake level drops below the outlet elevation about one year in seven; e) 6300 to 4300 yrs BP lake level was below the present outlet elevation long enough for large trees to grow; f) the date of the peak snowmelt runoff is shifting toward earlier dates; g) after accounting for annual runoff, loads of nutrients and suspended sediment have declined significantly in some basin streams since 1980. Downscaled outputs from GCM climatic models have recently been used to drive hydrologic models and a lake clarity model, projecting future trends in the lake and watersheds. Results show a) the temperature and thermal stability will likely continue to increase, with deep mixing shutting down in the latter half of this century; b) the lake may drop below the outlet for an extended period beginning about 2085; c) the annual snowpack will continue to decline, with earlier snowmelt and shift from snowfall to rain; d

  13. Late Holocene distribution of lake sediment and peat in NE Uppland, Sweden

    Bergstroem, Elisabeth [Stockholm Univ. (Sweden). Dept. of Physical Geography and Quaternary Geology


    This report is part of a larger project conducted by SKB. The aim is to carry out investigations of eight lakes and one bog, with respect to stratigraphic and geographic distribution of sediment and peat. More than 150 corings were made with a Russian peat sampler. The bog was investigated regarding its isolation from the Baltic basin. This site is included in the shore displacement model elaborated from other sites situated at the same isobase for the Litorina Sea. Northern Uppland is an area with a smooth topography, which also affects the lake basins. The water depth is generally shallow, 1-3 metres. The bedrock mainly consists of granitoids. A few areas consist of meta volcanics, younger granites and pegmatites. The Quaternary deposits in Uppland are more or less calcareous, which is reflected in the rich flora with e. g. orchids and saw grass. Till is the most common deposit in the area covering considerable areas but rarely forming geomorphological features. Glaciofluvial deposits i. e. eskers, stretches in more or less S-N direction, being generally small. In northern Uppland, large areas are covered by mires. Most of them are affected by human activities in the form of ditching; some are used for cultivation or as pasture land. One site, Vissomossen, with a levelled isolation threshold at 27. 4 m a. s. l. , is mainly a fen, with a bog developing in the central part. Diatom analyses and AMS dates show that the basin was earlier a bay of the Litorina Sea and isolated 3500-3600 {sup 14}C years BP. The former lake basin was as large as the present extension of the mire. Accumulated material reveals that the lake during time has been filled in with sediment, overgrown and finally forming a mire. The result of the present study is summarized as an extended shore displacement model for northern Uppland, and it reflects an ongoing regression in the area. A decline in regression can be compared with the Litorina transgression 3 (L3), which in the Stockholm area is

  14. Reconstruction of paleostorm history using geochemical proxies in sediment cores from Eastern Lake, Florida

    Das, O.; Wang, Y.; Donoghue, J. F.; Coor, J. L.; Kish, S.; Elsner, J.; Hu, X. B.; Niedoroda, A. W.; Ye, M.; Xu, Y.


    Analysis of geochemical proxies of coastal lake sediments provides a useful tool for reconstructing paleostorm history. Such paleostorm records can help constrain models that are used to predict future storm events. In this study, we collected two sediment cores (60 and 103 cm long, respectively) from the center of Eastern Lake located on the Gulf coast of NW Florida. These cores, which are mainly composed of organic-rich mud and organic-poor sand, were sub-sampled at 2-3mm intervals for analyses of their organic carbon and nitrogen concentrations as well as δ13C and δ15N isotopic signatures. Selected samples were submitted for radiocarbon dating in order to establish a chronological framework for the interpretation of the geochemical data. There are significant variations in δ13C, δ15N, C%, N% and C/N with depth. The δ13C and δ15N values vary from -21.8‰ to -26.7‰ and 2.6‰ to 5‰, respectively. The stable isotopic signatures of carbon and nitrogen indicate that the sources of organic matter in sediments include terrestrial C3 type vegetation, marine input from Gulf of Mexico and biological productivity within the lake, such as phytoplankton and zooplankton growing in the lacustrine environment. The δ13C and δ15N values exhibit significant negative excursions by 2‰ in a 30 cm thick sand layer, bounded by a rapid return to the base value. A positive shift in the δ15N record observed in the upper part of the cores likely reflects increased anthropogenic input of N such as sewage or septic tank effluents associated with recent development of areas around the lake for human habitation. Similarly, organic C% and N% range from 5.8 to 0.4 and 0.4 to 0.1, respectively. A prominent negative shift by 2σ relative to the baseline in C% and N% has been observed at approx. 55 to 58 cm depth, consisting of an organic-poor sand layer. This shift in C% and N% can be correlated with the negative shift in the δ13C and δ15N values, indicating a major storm event

  15. Responses in sediment phosphorus and lanthanum concentrations and composition across 10 lakes following applications of lanthanum modified bentonite

    Dithmer, Line; Nielsen, Ulla Gro; Lurling, Miguel; Spears, Bryan M.; Yasseri, Said; Lundberg, Daniel; Moore, Alanna; Jensen, Nicholai D.; Reitzel, Kasper


    A combined field and laboratory scale study of 10 European lakes treated between 2006 and 2013 with a lanthanum (La) modified bentonite (LMB) to control sediment phosphorus (P) release was conducted. The study followed the responses in sediment characteristics including La and P fractions and bin

  16. Responses in sediment phosphorus and lanthanum concentrations and composition across 10 lakes following applications of lanthanum modified bentonite

    Dithmer, Line; Nielsen, Ulla Gro; Lürling, Miquel;


    A combined field and laboratory scale study of 10 European lakes treated between 2006 and 2013 with a lanthanum (La) modified bentonite (LMB) to control sediment phosphorus (P) release was conducted. The study followed the responses in sediment characteristics including La and P fractions...

  17. Heavy metal pollution status and ecological risks of sediments under the influence of water transfers in Taihu Lake, China.

    Liu, Jiajia; Wang, Peifang; Wang, Chao; Qian, Jin; Hou, Jun


    The effects of water transfer projects on water channels and the receiving water involved need to be understood. In this research, the compositions and particle size distributions of surface sediment and the Cd, Cr, Cu, Ni, Pb, and Zn contents and distributions in the sediment along a water transfer route from the Wangyu River to Taihu Lake, China, were studied. The correlative relationship between the grain size trend and heavy metal content distribution suggested that heavy metals in Wangyu River sediment have affected the heavy metal contents of Taihu Lake sediment through silt and clay migrating in the transferred water. Enrichment factors and potential ecological risk values were calculated. Low levels of potential ecological risks are posed at 20 sampling sites in Taihu Lake, but higher-to-serious risks (potential ecological risk values >275) are posed at all Wangyu River sites. Toxicity of heavy metals (Cd, Cu, Zn, and Ni) in the Wangyu River sediments is more serious than those in the Taihu Lake, but is similar to the entrance of Gonghu Bay. Multivariate statistical analyses (Pearson correlation, cluster, and factor analyses) suggested heavy metals in the study area have many sources, and the relationships between particle migration and heavy metal contents indicated transferring water are likely to lead to adverse ecological risks being posed in Taihu Lake.

  18. Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

    Wang, Changhui [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Bai, Leilei [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate University of Chinese Academy of Sciences (China); Jiang, He-Long, E-mail: [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Huacheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China)


    Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

  19. Inorganic data from El'gygytgyn Lake sediments: stages 6–11

    V. Wennrich


    Full Text Available Geochemical study was performed on sediment of deep drilling core from El'gygytgyn Lake, located in central Chukotka, northeastern Russia (67°30' N; 172°05' E. Major and rare elements were determined by X-ray fluorescence spectroscopy (XRF on 600 samples covering the timeframe between ca. 450 and 125 ka corresponding to Marine Isotope Stages (MIS 11 to 6. Inorganic geochemistry data indicates significant variations in the elemental compositions corresponding to the glacials and interglacials periods. Interglacial sediments are characterized by high contents of SiO2, Na2O, CaO, K2O, Sr and are depleted in Al2O3, Fe2O3, TiO2, MgO. Extreme enrichments in SiO2 during MIS 11.3 and 9.3 are caused by an enhanced flux of biogenic silica (BSi. Geochemical structure of stage 11 shows very similar peculiarities to features of stage 11 from records of Lake Baikal/SE Siberia and Antarctic ice cores. High contents of TiO2, Fe2O3, MgO, Al2O3, LOI, Ni, Cr and Zr are typical for sediments of glacial stages, among those MIS 7.4 and 6.6 are the most marked. Peaks in the Fe2O3 content and coinciding low Fe2O3/MnO ratios during glacials indicate reducing condition in the sediments. This is also supported by enrichments in P2O5 and MnO, indicating an increased abundance of authigenic fine grained vivianite. Some elemental ratios indicate an enhanced alteration of glacial sediments accompanied by a loss of mobile elements, like Na, Ca, K and Sr. The higher alteration of sediments can presumably be traced back to changes in the sedimentation regime and diagenetic processes, and thus, reflects environmental changes.

  20. Manganese redox cycling in Lake Imandra: impact on nitrogen and the trace metal sediment record

    J. Ingri


    Full Text Available Sediment and water samples from the mine-polluted Yokostrovskaya basin in Lake Imandra have been analysed. Three major processes have influenced the accumulation and distribution of metals in the sediment: (1 Development of the apatite-nepheline and the sulfide ore mining industries. (2 Secondary formation of sulphides in the upper sediment column. (3 Redox cycling of Mn in the surface sediment and in the bottom water.

    This study demonstrate the dominant role of the Mn redox cycling in controlling distribution of several major and trace elements, especially during the winter stratification period. Mn oxides act as a major scavenger and carrier for the non-detrital fraction of Al, Ca, K, Mg, P, Ba, Co, Cu, Ni, Mo and Zn in the bottom water. Aluminium, Ca, K, Mg, P, Cu, Ni and Zn are mainly sorbed at the surface of the particulate Mn phase, while Ba and Mo form a phase (or inner sphere complex with Mn. Co is associated with the Mn-rich phase, probably by oxidation of Co(II to a trivalent state by the particulate Mn surface. Formation and dissolution of Mn particles most likely also control anoxic ammonium oxidation to nitrate and reduction of nitrate to N2. It is shown that secondary sulphides in Lake Imandra sediments are fed with trace metals primarily scavenged from the dissolved phase in the water column. This enrichment process, driven by the Mn-redox cycle, therefore changes the sediment record by the transfer of a dissolved pollution signal to the particulate sediment record, thus making it more complicated to trace direct influence of particles from different pollution sources.

  1. Identifying the annual signal in laminated clastic sediments from a Late Pleistocene lake succession

    Barrett, Samuel; Starnberger, Reinhard; Spötl, Christoph; Brauer, Achim; Dulski, Peter


    A thick (>250m) succession of laminated lacustrine sediments at the Baumkirchen site in the Inn Valley (Austria) indicates the presence of a lake or series of lake phases existing during Marine Isotope Stage 3. The laminations are highly complex, entirely clastic, and vary considerably in thickness and internal structure. Despite high sedimentation rates of 5-6 cm per year indicated by radiocarbon and pollen data, there is no systematic macroscopic annual pattern in the laminations which could be used to develop a high-resolution (varve) chronology. Microscopic investigations of thin sections revealed sub-mm to cm-scale silt layers punctuated by very thin (0.25-2 mm) clay-rich layers spaced semi-regularly between 2 and 8 cm where present. The spacing and small grain size of these thin layers suggests a possible annual process responsible for their formation: rain-out of the fine suspended sediment from the water column during winter, when fluvial discharge into the lake was negligible and its surface was frozen. These potentially annual layers are not reliably identifiable macroscopically, however, analysis of X-ray fluorescence core scan data revealed the layers to be enriched in several heavy metals: most strongly in Zn but also in Pb, Cu and Ni. Possible carrier minerals of these heavy metals are currently being investigated. The radiocarbon chronology (in the short upper section where it is available) and heavy metal peak counting agree within error suggesting the heavy metal enriched clay-rich layers are mostly annual. Available X-ray fluorescence data for 150 m of the section suggest no significant long-term changes in annual layer spacing (i.e. sedimentation rate) from the 5-6 cm average indicated by the radiocarbon data, although there is a high degree of small-scale variation. Preliminary optically stimulated luminescence dates point to the presence of several hiatuses in this succession suggesting a fragmented record containing several lake periods of

  2. Application of a new sediment contact test with Myriophyllum aquaticum and of the Aquatic Lemna test to assess the sediment quality of Lake Skadar

    Stesevic, D.; Sundic, D.; Mijovic, S. [Montenegro Univ., Podgorica (