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Sample records for lake hovsgol nw

  1. Tectonics of the baikal rift deduced from volcanism and sedimentation: a review oriented to the Baikal and Hovsgol lake systems.

    PubMed

    Ivanov, Alexei V; Demonterova, Elena I

    2009-01-01

    As known from inland sedimentary records, boreholes, and geophysical data, the initiation of the Baikal rift basins began as early as the Eocene. Dating of volcanic rocks on the rift shoulders indicates that volcanism started later, in the Early Miocene or probably in the Late Oligocene. Prominent tectonic uplift took place at about 20 Ma, but information (from both sediments and volcanics) on the initial stage of the rifting is scarce and incomplete. A comprehensive record of sedimentation derived from two stacked boreholes drilled at the submerged Akademichesky ridge indicates that the deep freshwater Lake Baikal existed for at least 8.4 Ma, while the exact formation of the lake in its roughly present-day shape and volume is unknown. Four important events of tectonic/environmental changes at about approximately 7, approximately 5, approximately 2.5, and approximately 0.1 Ma are seen in that record. The first event probably corresponds to a stage of rift propagation from the historical center towards the wings of the rift system. Rifting in the Hovsgol area was initiated at about this time. The event of ~5 Ma is a likely candidate for the boundary between slow and fast stages of rifting. It is reflected in a drastic change of sedimentation rate due to isolation of the Akademichesky ridge from the central and northern Lake Baikal basins. The youngest event of 0.1 Ma is reflected by the (87)0Sr/ (86)Sr ratio increase in Lake Baikal waters and probably related to an increasing rate of mountain growth (and hence erosion) resulting from glacial rebounding. The latter is responsible for the reorganization of the outflow pattern with the termination of the paleo-Manzurka outlet and the formation of the Angara outlet. The event of approximately 2.5 Ma is reflected in the decrease of the (87)Sr/(86)Sr and Na/Al ratios in Lake Baikal waters. We suggest that it is associated with a decrease of the dust load due to a reorganization of the atmospheric circulations in Mainland

  2. Paleoclimatic record of the late Quaternary from a gravity core sediment of Lake Hovsgol in northern Mongolia

    NASA Astrophysics Data System (ADS)

    Cheong, D.; Kim, B.

    2007-12-01

    Gravity core sediment (HS 7) from Lake Hovsgol(Mongolia) is divided into three sedimentary units on the basis of sediments texture, water contents, occurrence of fossils and sediment color. Unit 1(27¢¦128§¯) is generally massive and is crudely stratified. Ostracods are well preserved over the all interval of Unit1, but diatoms are not well preserved. At Unit2(9¢¦27§¯), mud content is slightly low and lamination is well developed. It is dark greenish gray in the upper part, and dark greenish gray is alternating with light brownish gray in the lower part. Diatom contents increase towards the top and ostracods fragments disappear at the top of Unit 2. Unit3(0¢¦9§¯) is laminated mud in olive gray color. Diatom contents are high but ostracods are not observed in this unit. According to 14C age dating results, we assumed that Unit1 is Pleistocene sediment, Unit2 is sediment of a transitional stage and Unit 3 is Holocene sediment. Chemical composition of trace elements from ostracods show variations through Unit1, especially showing a distinct change at 95¢¦100§¯ interval. It matches to the distribution of ostracod at this interval. Contents of ostracod decrease at the interval and contents of Cytherissa lacustris decrease, but Limnocythere inopinata increase. It was interpreted that warm air was supplied to Lake Hovsgol after LGM(Last Glacial Maximum), causing ice melting. Consequently the bottom environment of Lake Hovsgol experienced some changes as the lake level increased little bit. At the top of Unit 1 appear a lots of pyrite which are arranged in line, and diatoms occure but ostracods are not observed toward the top of Unit 2, and lamination is developed in Unit 2. It means the bottom environment of Lake Hovsgol changed to anoxic condition. At that time, plenty of water was supplied into the lake, resulting in water stratification and cutting off oxygen supply to the bottom of Lake Hovsgol. It made the lake level rise higher, so that the bottom

  3. Biological nitrate utilization in south Siberian lakes (Baikal and Hovsgol) during the Last Glacial period: the influence of climate change on primary productivity

    NASA Astrophysics Data System (ADS)

    Nara, Fumiko Watanabe; Watanabe, Takahiro; Kakegawa, Takeshi; Minoura, Koji; Imai, Akio; Fagel, Nathalie; Horiuchi, Kazuho; Nakamura, Toshio; Kawai, Takayoshi

    2014-04-01

    Stable nitrogen isotope ratios (δ15N) in sediment cores recovered from two Siberian lakes (Baikal and Hovsgol) are determined in order to evaluate the biologically mediated nitrogen cycle from the Last Glacial period to the postglacial period. The ranges of δ15N values from the two lakes are similar, varying from +2.8‰ to +6.7‰. The high values of δ15N (around +6‰) during the Last Glacial Maximum (LGM, 26.5-19 cal ka BP) indicate that a larger fraction of the available nitrate in both lakes was utilised by phytoplankton. A cool and dry climate during the LGM may have limited the input of terrestrial nitrate, resulting in the use of a large fraction of the nitrate, and low productivity, in both lakes. The use of a smaller fraction of the nitrate by phytoplankton in both lakes after the LGM (19-12 cal ka BP) is reflected in the lower δ15N values (down to +3.0‰). The increase in summer insolation after the LGM caused increased vertical mixing of the lake water column, which transported nitrate upwards from the deeper waters and into the photic zone. The reduced rate of nitrogen consumption after the LGM indicates that nitrate was more readily available to phytoplankton at this time and did not limit their activities. This change suggests that other factors limited phytoplankton activity during this period. At the climatic transition between Oxygen Isotope Stages 2 and 1 (around 11.5 cal ka BP), the rapid increase in δ15N (from +3.0‰ to +6.0‰) reflected a rapid increase in nitrate utilization. At this transition, increases in precipitation and lake levels, which were associated with the increased intensity of the East Asian Monsoon, may have brought a large influx of nutrients required by the phytoplankton into the lakes from the watershed. This hydrological change led to increased phytoplankton activity in both lakes, resulting in increased nitrate consumption. The δ15N data obtained here from the sediments of lakes Baikal and Hovsgol suggest that

  4. Monitoring of Permafrost in the Hovsgol Mountain Region, Mongolia

    NASA Astrophysics Data System (ADS)

    Sharkhuu, A.; Natsagdorj, S.; Etzelmuller, B.; Heggem, E. S.; Nelson, F. E.; Shiklomanov, N.; Goulden, C.

    2005-12-01

    - facing ones. Intensive degradation of permafrost is also caused by human activities associated with land use. For example, initial results of short term (3 years) monitoring of permafrost in the northeastern shore valleys of Lake Hovsgol show that the depth of the active layer varies from 1.4 m in Borsog valley in the south to 4.8 m in Turag valley in the north, apparently in relation to livestock grazing pressure. We have also begun monitor active frost heaving on pingos in the eastern shore valleys and active thaw settlement (thermokarst) in the Darhad depression. In general, the permafrost in the Hovsgol Mountain Region is degrading more intensively than in the Khentei and Khangai Mountain Regions. The recent degradation of permafrost under the influence of climate warming and human activities leads to some changes in natural and ecological balance. In particular, our observations have indicated deforestation in the taiga zone and desertification in the steppe zone of the Hovsgol region.

  5. Seasonal changes of methane concentration in boreal lakes of NW Russia

    NASA Astrophysics Data System (ADS)

    Zabelina, Svetlana; Desmukh, Chandrashekhar; Pokrovsky, Oleg; Savvichev, Alexander; Shirokova, Liudmila; Guerin, Frederic; Zakharova, Elena

    2010-05-01

    Methane (CH4), produced by methanogenic Archaea under strictly anoxic conditions in sediments, is an important atmospheric greenhouse gas, contributing to global warming. Besides, the importance of boreal lakes in global methane evaluation stem from the high coverage of arctic and subarctic land surface by lakes of glacial or thermokarst origin. The first step in the evaluation of methane biogeochemical cycle in high latitudes is the measurement of its concentration in the water column and bottom porewater sediments. In this work, we investigated several typical seasonally stratified lakes in Arkhnagelsk region of the NW Russia. Methane concentrations profiles were measured in the water column and sediment porewaters of two lakes of the Kenozersky National Park (KNP) (Lake Maselgskoe and Lake Vilno) located in the middle of taiga zone southwest from Arkhangelsk, and the lake Svjatoe located in the Geobiopsheric station "Rotkovetz" during the summer (2007, 2009) and winter (2008) stratification period. In addition, the lake Maselgskoe was studied during spring and autumn water overturn. During summer period, methane profiles in the lake Maselgskoe showed three zones with differed CH4 concentration: constant concentration around 0.22 µmol/L in the surface layer (0 to 6-7 m), then gradual decrease to 0.05 μmol/L (8 to 15 m) and significant increase to 80 μmol/L in near-bottom water. During autumn lake water overturn, mean СН4 concentration (0.31 µmol/L) in the water column of the lake Maselgskoe gradually but decreased insignificant from the surface to depth horizons. Stratified lake Svyatoe in 2007 and shallow lake Vilno in 2009 demonstrated similar features of CH4 concentration profile, however near-bottom concentration in lakes was an order of magnitude less than in Maselgskoe. The sediment porewaters of stratified lakes exhibit the concentration of methane ranging from 0.43 to 2.0 mmol/L in summer and from 1 to 2.4 mmol/L in winter in lake Maselgskoe and

  6. The endemic mollusks reveal history of the long-lived Pliocene Lake Slavonia in NW Croatia

    NASA Astrophysics Data System (ADS)

    Mandic, Oleg; Kurečić, Tomislav; Neubauer, Thomas A.; Harzhauser, Mathias

    2015-04-01

    The present investigation deals with the fossil mollusk record of the long-lived Pliocene Lake Slavonia settled in the southern Pannonian Basin. The samples originate from Vukomeričke gorice, a low hill-range situated north of the Kupa River in the area between the towns of Zagreb, Sisak and Karlovac in NW Croatia. Representing the SW margin of the Lake Slavonia the freshwater deposits alternate there with the alluvial series, providing altogether about 400-m-thick, Pliocene continental succession, known in literature by informal name Paludina beds (acc. to a junior synonym of Viviparus). The endemic fauna of the Lake Slavonia became particularly well-known in the late 19th century after Melchior Neumayr demonstrated that the gradual evolutionary change of the mollusk phenotypes toward more complex morphology represents a function of adaptation to environmental change in the paleolake. Even Charles Darwin commented that result as by far the best case which I have ever met with, showing the direct influence of the conditions of life on the organization. The deposition in the Lake Slavonia (~4.5 to ~1.8 Ma) coincides with the Pliocene Climate Optimum (PCO), but captures also the transition into the Pleistocene climate marked by the initial Ice Age pulse at 2.59 Ma. The increase of polar temperatures resulted during PCO in a significant melting of the ice caps leading to a global sea level rise tentatively getting up to 25 m higher than today. Coincidence of the climate and geodynamic settings in southeastern Europe provided conditions supporting extended settlement of lacustrine environments including Lake Slavonia, Lake Kosovo, Lake Transylvania and Lake Dacia, all characterized by explosive adaptive radiations of viviparid snails. In particular, the latter adaptive radiations resulted in the regional phylostratigraphy of Lake Slavonia Viviparus species enabling excellent stratigraphic control for the investigated deposits. Hence, based on this evidence, the

  7. Earthquake Records of North Anatolian Fault from Sapanca Lake Sediments, NW Anatolia

    NASA Astrophysics Data System (ADS)

    Yalamaz, Burak; Cagatay, Namık; Acar, Dursun; Demirbag, Emin; Gungor, Emin; Gungor, Nurdan; Gulen, Levent

    2014-05-01

    We determined earthquake records in sediment cores of Sapanca Lake which is a pull-apart basin located along the North Anatolian Fault zone in NW Anatolia. The lake has a maximum depth of 55 m, and a surface area of 46.8 km2, measuring 16 km in E-W and 5 km in N-S directions. A systematic study of the sedimentological, physical and geochemical properties of three water-sediment interface cores, up to 75.7 cm long, located along depth transects ranging from 43 to 51.5 m water depths. The cores were analyzed using Geotek Multi Sensor Core Logger (MSCL) for physical properties, laser particle size analyzer for granulometry, TOC Analyzer for Total Organic Content (TOC) and Total Inorganic Carbon (TIC) analysis, Itrax-XRF Core Scanner for elemental analysis and digital X-RAY Radiography. The geochronology was determined using AMS radiocarbon and radionuclide methods. The Sapanca Lake earthquake records are characterized by mass flow units consisting of grey or dark grey coarse to fine sand and silty mud with sharp basal and transional upper boundaries. The units commonly show normal size grading with their basal parts showing high density, and high magnetic susceptibility and enrichment in one or more elements, such as Si, Ca, Tİ, K, Rb, Zr and Fe, indicative of coarse detrial input. Based on radionuclide and radiocarbon analyses the mass flow units are correlated with 1999 İzmit and Düzce earthquakes (Mw=7.4 and 7.2, respectively) , 1967 Mudurnu earthquake (Mw= 6,8), and 1957 Abant (Mw= 7.1) earthquake. Keywords: Sapanca Lake, North Anatolian Fault, Earthquake, Grain size, Itrax-XRF, MSCL

  8. Effect of depositional regimes on polycyclic aromatic hydrocarbons in Lake Bled (NW Slovenia) sediments.

    PubMed

    Muri, Gregor; Wakeham, Stuart G

    2009-09-01

    Polycyclic aromatic hydrocarbons (PAH) were measured in sediment cores from two contrasting depositional regimes in urban Lake Bled (NW Slovenia). The concentration of PAH in surface sediments, mostly derived from combustion, was higher in Zaka Bay where bottom waters are permanently oxic, than in the western basin where bottom waters oscillate between suboxic and anoxic (1930 vs. 1150ngPAHg(-1) dry weight (dw), respectively). This pattern is the reverse of what might be expected if PAH were to preferentially degrade under oxic conditions. Two PAH from non-combustion sources, perylene and retene, are also present in the sediments. Post-depositional diagenetic formation of perylene appeared to occur only in anoxic sediments. Differences in the source of sedimentary organic matter (autochthonous vs. allochthonous) is probably not a major factor in perylene formation, since the two locations have markedly different sources of organic matter but quite similar concentrations of perylene in deeper sediments, ranging from 250 to 350ngg(-1)dw. Thus, redox conditions may play a role in perylene generation. On the other hand, redox conditions in general can not be the only or even the major factor affecting the fate of sedimentary PAH since uniform compositions and depth distributions for pyrolytic PAH were observed in both cores, in spite of the two locations differ in redox, mixing and biota conditions. Thus, degradative loss of PAH is unlikely in Lake Bled sediments.

  9. Heterotrophic bacterioplankton control on organic and inorganic carbon cycle in stratified and non-stratified lakes of NW Russia

    NASA Astrophysics Data System (ADS)

    Shirokova, Liudmila; Vorobjeva, Taissia; Zabelina, Svetlana; Moreva, Olga; Klimov, Sergey; Shorina, Natalja; Chupakov, Artem; Pokrovsky, Oleg; Audry, Stephan; Viers, Jerome

    2010-05-01

    Lakes of boreal zone regulate the fate of dissolved carbon, nutrients and trace metals during their transport from the watershed to the ocean. Study of primary production - mineralization processes in the context of carbon biogeochemical cycle allows determination of the rate and mechanisms of phytoplankton biomass production and its degradation via aquatic heterotrophic bacteria. In particular, comparative study of vertical distribution of Dissolved Organic Carbon (DOC) in stratified and non-stratified lakes allows establishing the link between biological and chemical aspects of the carbon cycle which, in turns, determines an environmental stability and recovering potential of the entire ecosystem. In order to better understand the biogeochemical mechanisms that control dissolved organic and inorganic carbon migration in surface boreal waters, we studied in 2007-2009 two strongly stratified lakes (15-20 m deep) and two shallow lakes (2-4 m deep) in the Arkhangelsk region (NW Russia, White Sea basin). We conducted natural experiments of the lake water incubation for measurements of the intensity of production/mineralization processes and we determined vertical concentration of DOC during four basic hydrological seasons (winter and summer stratification, and spring and autumn lake overturn). Our seasonal studies of production/mineralization processes demonstrated high intensity of organic matter formation during summer period and significant retard of these processes during winter stagnation. During spring period, there is a strong increase of bacterial destruction of the allochtonous organic matter that is being delivered to the lake via terrigenous input. During autumn overturn, there is a decrease of the activity of phytoplankton, and the degradation of dead biomass by active bacterial community. Organic matter destruction processes are the most active in Svyatoe lake, whereas in the Beloe lake, the rate of organic matter production is significantly higher than

  10. Waterborne and on-land electrical surveys to suggest the geological evolution of a glacial lake in NW Italy

    NASA Astrophysics Data System (ADS)

    Colombero, Chiara; Comina, Cesare; Gianotti, Franco; Sambuelli, Luigi

    2014-06-01

    Geophysical surveys on and around the Candia Lake, located NE of Turin (NW Italy), in the internal depression of the Ivrea Morainic Amphitheater (IMA) right frontal sector, are reported in this paper. The surveys were intended to obtain a geophysical characterization of the lakebed, to investigate the interconnection paths between surface water and groundwater and to be used as a first general survey for suggesting the geological processes which lead to the actual morphology. An extensive waterborne continuous vertical electrical sounding (CVES) survey consisting of 15 profiles, with a total length of about 19 km of acquisition, was carried out on the lake surface. The processing of the acquired profiles with a laterally constrained inversion (LCI) approach lead to the reconstruction of the lakebed sediment distribution, down to 10 m depth. Self potential (SP) data recorded on the lake surface have also been analyzed. Moreover, to verify the areal distribution of the deposits, three electrical resistivity tomographies (ERTs) were carried out on land near the northern and southern shores of the lake. The combination of the geophysical survey results with hydrogeological information and geological observations and interpretations allowed the characterization of the submerged deposits, the probable identification of the main areas of groundwater recharge and the preliminary reconstruction of the lake genesis.

  11. Using discontinuous wave-cut terraces to reconstruct the history of former glacial lake levels: the example of Lake Ojibway in NW Quebec (Canada)

    NASA Astrophysics Data System (ADS)

    Daubois, V.; Roy, M.; Veillette, J. J.

    2012-12-01

    The decay of the southern Laurentide ice sheet maring during the last deglaciation led to the development of Lake Agassiz and Lake Ojibway that covered large areas in the western prairies and in NE Ontario-NW Quebec, respectively. The history of glacial lakes is commonly based on the study of strandlines that generally consist of sandy beaches (and near-shore facies) or boulder ridges. However, the use of this approach is limited in the main Ojibway basin where the surficial geology consists predominantly of thick accumulation of fine-grained glaciolacustrine deposits that mask most deglacial landforms and the underlying bedrock. Nonetheless, earlier mapping programs in this flat-lying clay plain revealed a complex sequence of discontinuous small-scale cliffs that are made of Ojibway rhythmites. These terrace-like features range in size from 4 to 7 m in height and can generally be followed for 10 to 100's of meters, and sometimes for several kms. These small-scale features are interpreted to represent raised shorelines that were cut into glaciolacustrine sediments by lakeshore erosional processes (i.e., wave action). These so-called wave-cut benches (WCBs) occur at elevations ranging mostly from 3 to 30 m above the present level of Lake Abitibi (267 m), one of the lowest landmarks in the area. Here we evaluate the feasibility of using this type of shorelines to constrain the evolution of Ojibway lake levels in NW Quebec. For this purpose, a series of wave-cut terraces (WCBs) were measured along two north-south transects of about 40 km in length in the Lake Abitibi region. The absolute elevation of more than 70 WCBs was determined with a Digital Video Plotter software package using 1:15K air-photos, coupled with precise measurements (x,y,z coordinates) of control points, which were measured with a high-precision Global Navigation Satellite System tied up to known geodesic survey markers. Preliminary results suggest that Lake Ojibway experienced at least three

  12. Evolution of Chaka Salt Lake in NW China in response to climatic change during the Latest Pleistocene Holocene

    NASA Astrophysics Data System (ADS)

    Xingqi, Liu; Dong, Hailiang; Rech, Jason A.; Matsumoto, Ryo; Bo, Yang; Yongbo, Wang

    2008-04-01

    The Late Pleistocene and Holocene hydrologic balance of Chaka Salt Lake in the eastern Qaidam Basin of NW China was studied based on the analysis of lithostratigraphy, mineralogy, total organic carbon, and total nitrogen from a 9.0-m long sediment core. An age-depth model for the lake sediments is based on eight accelerator mass spectrometry (AMS) 14C measurements of organic matter and a 1700-year radiocarbon reservoir correction. The Pitzer model was used to calculate the sequence of minerals precipitated as a function of salinity assuming that the initial lake water was recharged from adjacent rivers and springs. Lake salinity values were derived from a good match between the calculated and observed mineral sequences. Our multi-proxy based hydrologic reconstruction of Chaka Lake indicates that it was a clastic-dominated, freshwater lake between 17.2 and 11.4 cal ka BP, which may have resulted from the input of glacial water into the lake at that time. During the Lateglacial and Holocene, a warm climatic regime predominated between 13.9 and 12.7 cal ka BP and then a cold climatic regime prevailed between 12.7 and 11.4 cal ka BP. These warm and cold periods correlate with the Bølling-Allerød and Younger Dryas events in the region. Beginning at 11.4 cal ka BP, a saline or hypersaline lake developed, which may have resulted from increased summer insolation and temperatures. These conditions persisted throughout the Holocene. Modeling indicates that lake salinity fluctuated between 66 and 223 ppt from 11.4 to 7.2 cal ka BP and then increased to 223-322 ppt between 7.2 and 6.0 cal ka BP, when most regions of China recorded high moisture availability (i.e. the so-called "mid-Holocene Climatic Optimum"). Lake salinity decreased to 66-223 ppt during a short time period between 6.0 and 5.3 cal ka BP, possibly caused by reduced evaporation. Subsequently, salinity values rapidly increased to 223-322 ppt between 5.3 and 5.2 cal ka BP and a hypersaline lake with a salinity

  13. Polychlorinated biphenyls and organochlorine pesticides in atmospheric air of the Northern Hovsgol region in 2008-2013

    NASA Astrophysics Data System (ADS)

    Mamontova, E. A.; Tarasova, E. N.; Goreglyad, A. V.; Tkachenko, L. L.; Mamontov, A. A.; Kuzmin, M. I.

    2015-10-01

    Results of the study of organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB) from the listing of the Stockholm Convention in atmospheric air of the Northern Hovsgol region at the base of the "Khankh" stationary, Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, in 2008-2013 in the absence of clear sources of these compounds are considered. Quantitative and qualitative changes in the concentration of PCB and OCP in atmospheric air of the Northern Hovsgol region in 2008-2013 characterizing the influence of natural (annual temperature variations) and anthropogenic (atmospheric transportation from the territories of neighboring countries) are shown.

  14. Holocene lake level fluctuations of a small alpine lake in the Qilian Mountains, NW China: a comparison of chironomid, ostracod, pollen and geochemistry data.

    NASA Astrophysics Data System (ADS)

    Mischke, S.; Herzschuh, U.

    2003-04-01

    A core of 14 m length was drilled in a small alpine lake in the Qilian Mountains, NW China. The lake Luanhaizi has a drainage area of about 30 km2 and is situated at an altitude of 3200 m which represents the altitude of the present regional upper timberline. Due to the small size of the open-basin lake (surface area about 1 km2) and the sharply outlined catchment area the lake is regarded as a very sensitively and rapidly responding ecosystem. Analyses of ostracod shells, head capsules of larval chironomids and pollen and spores were conducted and the organic and carbonate content (LOI), element concentrations and magnetic susceptibility of core samples determined. Ostracod taxa mainly comprise Candona candida, C. neglecta, C. rawsoni, Cyclocypris ovum, Cypridopsis vidua, Fabaeformiscandona caudata, F. danielopoli, F. hyalina, Herpetocypris chevreuxi, Heterocypris salina, Ilyocypris cf. bradyi, I. echinata, I. lacustris and Limnocythere inopinata. They may be used to distinguish periods of low lake levels corresponding to a dense cover of aquatic plants at the lake bottom from stages of higher lake levels and a corresponding decrease in macrophytes at the core site. Chironomid taxa belonging to Chironomus, Cladopelma, Glyptotendipes, Micropsectra, Paratanytarsus, Polypedilum, Psectrocladius and Tanytarsus further provide information on variations in benthic oxygen availability and lake level fluctuations. Several units of the core show high abundances of pollen and spores of higher aquatic and wetland plants and fungi (Cyperaceae, Hippuris, Myriophyllum and Glomus) indicating low lake levels. In contrast, algae such as Botryococcus, Pediastrum and Tetraedron were regarded to reflect higher water levels. Typha angustifolia-type, Typha latifolia, Alisma and Potamogeton were recorded in low abundances as well. The organic content of core samples averages 6 % displaying four alternating stages of distinct minima and maxima. Lowest values of about 1 % occur at the core

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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.

  16. New paleoreconstruction of transgressive stages in the northern part of Lake Ladoga, NW Russia.

    NASA Astrophysics Data System (ADS)

    Terekhov, Anton; Sapelko, Tatyana

    2016-04-01

    Lake Ladoga is one of the largest lakes in the world and the largest in Europe. The watershed of lake Ladoga covers the North-Western part of European Russia and the Eastern Finland. Lake basin is on the border between the Baltic shield and the East European Platform. The most consistent paleoreconstructions of Lake Ladoga history are based on bottom sediments of smaller lakes, which used to be a part of Ladoga in the past. The stages of Ladoga evolution are directly connected with the history of the Baltic Ice Lake (BIL) and of the Ancylus Lake. Water level of these lakes was significant higher than nowadays level. Lake Ladoga in its present limits used to be an Eastern gulf of BIL and Ancylus Lake. The preceding paleoreconstructions of Ladoga water level oscillations were undertaken by G. de Geer, J. Ailio, E. Hyyppä, K. Markov, D. Kvasov, D. Malakhovskiy, M. Ekman, G. Lak, N. Davydova, M. Saarnisto, D. Subetto and others. The new data on multivariate analysis of bottom sediments of lakes which used to belong to Ladoga, collected in the last few years, allows to create several maps of Ladoga transgressive stages in Late Glacial period and post-glacial time. A series of maps showing the extent of Ladoga transgression was created based on lake sediments multivariate analysis and a GIS-modeling using the digital elevation data with an accuracy of several meters and an open-source software (QGIS and SAGA). Due to post-glacial rebound of the lake watershed territory, GIS-modeling should comprise the extent of the glacioisostatic uplift, so the chart of a present-day uplift velocity for Fennoscandia of Ekman and Mäkinen was used. The new digital elevation models were calculated for several moments in the past, corresponding to the most probable dates of smaller lakes isolation from Lake Ladoga. Then, the basin of Ladoga was "filled" with water into GIS program to the levels sufficient for the smaller lakes to join and to split-off. The modern coastlines of Ladoga and

  17. Depth evolution of the Meirama pit lake, A Coruña, NW Spain

    NASA Astrophysics Data System (ADS)

    Delgado, Jordi; Juncosa-Rivera, Ricardo; Cereijo-Arango, José Luis; García-Morrondo, David; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja

    2016-04-01

    The Meirama pit lake is a water mass in the process of controlled flooding that, by the end of December 2015, can be described as a steadily stratified meromictic system. The deepest portion of the lake (monimolimnion) is isolated regarding the annual mixing dynamics (December/January) of the upper water body (mixolimnion), for which the depth of mixing is restricted to a water column of 35-40 m thick. Due to the contrasting flooding history (access of groundwater at the beginning and mixed access of stream/groundwater (being dominant the stream water) the deepest portion of the lake is separated from the upper, non-mixed layer by a marked chemocline. Strictly speaking, the monimolimnion of a meromictic lake extends to the waters located beneath the mixed lake layer. In the case of the Meirama Lake the monimolimnion is internally stratified and made of two major water bodies. From hereafter the deep and upper monimolimnion will be identified as bottom and middle sections of the lake while the mixolimnion is referred to as the surface layer. The general characteristics and evolution of the Meirama Lake have been reported elsewhere. In this work we focus on a summary description of the chemical evolution of the monimolimnion of the lake based on data gathered between 2009 and 2015 from the still on-going monitoring survey. The chemical evolution of the monimolimnion of the lake differs significantly from that of the mixolimnion. In general, surface water is sensible to seasonal fluctuations due to weather conditions, rainfall and biogeochemical processes. The middle and bottom sections are not sensible, in general, to this effects and their evolution obeys to a number of internal processes. In the case of temperature we observe a nearly constant gradient increase (0.001 °C/day) in the middle and deep lake waters up to the beginning of 2012, where it remains constant. The rise in temperature is likely due to the heat provided by groundwater seepage whose temperature

  18. Persistence time series analyses, complexity applied to natural hazards and the Quaternary lake history of the Lerma Valley, NW Argentina

    NASA Astrophysics Data System (ADS)

    Malamud, Bruce D.

    This dissertation explores the Quaternary history of a NW Argentina valley, persistence in synthetic self-affine time series, and complexity applied to natural hazards. Chapter one is an introduction. Chapter two examines the Lerma Valley in NW Argentina, today an externally drained basin which in the past was partially closed and contained a large fresh-water lake. Using geologic fieldwork laboratory work, and historical data analysis, we find that the lake was extant 1-50 ky during the period 0.78-0.1 Ma, had a surface area of 800-1300 kmsp2 and sedimentation rates of 1-10 m/ky. Modern denudation rates could supply enough sediment from the drainage to account for these rates, and the modern hydrologic regime could fill the lake with water in less than 500 years. Chapter three provides a framework to examine persistence techniques in self-affine time series. By using the Fourier spectral method, a white noise is appropriately filtered so that its power spectral density (S) depends upon frequency (f) according to S˜ fsp{-beta}. We examine fractional noises and walks with {-}3≤beta≤ 5 and Gaussian and log-normal distributions. The persistence analyses compared include autocorrelation, semivariogram, rescaled-range, Fourier power spectrum, extreme-value, and wavelet power spectrum. The last two are applied for the first time. In chapter four, self-organized critical (SOC) models are compared with actual events. The models have power-law noncumulative frequency-size distributions with exponent about 1.0, and the actual data have exponents 1.3-1.5 (forest-fires) and 2.3-3.3 (landslides). Actual forest fires are compared here for the first time with the forest-fire model; their robustness in one indicator of SOC behavior. Chapter five examines recurrence intervals of floods using power-law statistics applied to partial-duration series and the federally adopted log-Pearson type 3 (LP3) distribution applied to annual series. The great Mississippi River flood of 1993

  19. The role of clay minerals in the preservation of organic matter in sediments of qinghai lake, NW China

    USGS Publications Warehouse

    Yu, B.; Dong, H.; Jiang, H.; Lv, G.; Eberl, D.; Li, S.; Kim, J.

    2009-01-01

    The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our

  20. Climate and human impacts on the vegetation in NW Turkey: palynological insights from Lake Iznik since the Last Glacial

    NASA Astrophysics Data System (ADS)

    Miebach, Andrea; Niestrath, Phoebe; Roeser, Patricia A.; Litt, Thomas

    2015-04-01

    , the vegetation was also influenced by anthropogenic activities. During an early settlement phase near Lake Iznik, beginning ca. 8 ka cal BP (Roodenberg & Schier 2001), only minor changes in the pollen assemblage are registered. Still, evidence for human activity consolidates since the Early Bronze Age: cultivated trees, crops, and secondary human indicator species appeared, and forests got cleared. Subsequent fluctuations between extensive agricultural use and regeneration of the natural vegetation can be clearly correlated to the regional archaeological history. References: Roeser, P.A. (2014): Paleolimnology of Lake Iznik (NW Turkey) during the past ~ 31 ka cal BP. PhD thesis, University of Bonn, Germany. Roodenberg, J.J. & Schier, W. (2001): Radiocarbon determinations. In: Roodenberg, J.J. & Thissen, L.C. (eds.): The Ilıpınar Excavations II. PIHANS 93, Leiden: 257-278. Zohary, M. (1973): Geobotanical foundations of the Middle East. Gustav Fischer Verlag, Stuttgart.

  1. Emplacement of crystal-rich magmas: insights from the Snap Lake kimberlite intrusion (NW Territories, Canada)

    NASA Astrophysics Data System (ADS)

    Gernon, Thomas; Sparks, Steve; Field, Matthew; Ogilvie-Harris, Rachael

    2010-05-01

    The Cambrian Snap Lake kimberlite intrusion (Northwest Territories, Canada) is a complex segmented diamond-bearing ore-body. Detailed geological investigations suggest that the intrusion is a multi-phase body with at least four different magmatic lithofacies. In particular, olivine-rich (phlogopite-poor) and olivine-poor (phlogopite-rich) varieties of hypabyssal kimberlite have been identified. Key observations are that olivine-rich lithofacies (ORK) has a strong tendency to be located where the intrusion is thickest and that there is a good correlation between intrusion thickness, olivine crystal size and crystal content. Accordingly the olivine-poor lithofacies (OPK) tends to be most abundant where the intrusion is thinnest. Complimentary studies demonstrate that the lithofacies are geochemically distinct, and are characterised by different diamond abundances and size distributions. Our data and observations suggest that the ORK and OPK represent different magma phases that have experienced different processes during transport and emplacement. Heterogeneities in the kimberlite lithofacies are attributed to variations in intrusion thickness and structural complexities. Auto-xenoliths of ORK within the OPK suggest that the magmas are closely related in time and have clearly exploited the same fracture system during intrusion, resulting in various degrees of intermingling. The geometry and distribution of lithofacies points to magmatic cointrusion, and flow differentiation driven by fundamental rheological differences between the ORK and OPK phases. The presence of such low viscosity, crystal-poor magmas may explain how extremely crystal-rich kimberlite magmas (> 60 vol.%) are able to reach the surface and erupt in kimberlite diatremes. We envisage that the low viscosity OPK magma acted as a lubricant for the highly viscous ORK magma; such rheological segregation is a common feature in other magmatic systems. The Snap Lake intrusion provides important insights into

  2. Parasitism of Odonata by Arrenurus (Acari: Hydrachnidia) larvae in the Lake Świdwie, nature reserve (NW Poland).

    PubMed

    Zawal, Andrzej; Buczyński, Paweł

    2013-12-01

    Larvae of a vast majority of water mite species are parasites of aquatic insects. Owing to this, they migrate to new localities, and are able to survive unfavourable environmental conditions. This also concerns species from subgenus Arrenurus s. str., parasites of dragonflies. The detailed analysis of this phenomenon, however, has only been possible in the last several years, since the key to the identification of larvae from genus Arrenurus Dug. was published. In 2010, the parasitism of Arrenurus s. str. larvae on dragonflies in the Lake Świdwie reserve (NW Poland) was analysed. Larvae of 9 species of water mites were recorded on 107 imagines of dragonflies from 8 species. The following were identified as hosts of water mites for the first time: Anax imperator, Libellula quadrimaculata, and Leucorrhinia caudalis. The highest prevalence occurred in the case of: Erythromma najas and Lestes dryas (100%), Coenagrion pulchellum (96.5%), and C. puella (80.0%). Coenagrion pulchellum was infested by 9 species of parasites, C. puella by 6, and Erythromma najas and Lestes dryas by three species. The highest number of host species occurred in the case of Arrenurus maculator (5); followed by A. cuspidator, A. batillifer cf., A. bicuspidator, and A. tetracyphus (3 each); A. papillator, A. tricuspidator, and A. bruzelii (2 each), and A. claviger (1). Differentiation of preferences of particular parasites towards various parts of the host body was observed, probably related to the coevolution of parasites and hosts, and competition between the host species. The body sizes of the parasites suggest that approximately 50% of body size growth of water mites from subgenus Arrenurus s. str. occurs at the stage of parasitic larva. PMID:24338309

  3. Structural and stratigraphic features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992

    NASA Astrophysics Data System (ADS)

    Jeffries, M. O.; Morris, K.; Weeks, W. F.; Wakabayashi, H.

    1994-11-01

    Changes in ERS 1 C band synthetic aperture radar (SAR) backscatter intensity (σ°) from ice growing on shallow tundra lakes at three locations in NW Alaska are described. Ice core analysis shows that at all lakes on the coast at Barrow the ice, whether floating or frozen to the bottom, includes an inclusion-free layer overlying a layer of ice with tubular bubbles oriented parallel to the direction of growth. The clear ice may also be overlain by a discontinuous layer of bubbly snow ice. Backscatter is low (-16 to -22 dB) at the time of initial ice formation, probably due to the specular nature of the upper and lower ice surfaces causing the radar pulse to be reflected away from the radar. As the ice thickens during the autumn, backscatter rises steadily. Once the ice freezes to the lake bottom, regardless of the presence of forward scattering tubular bubbles, low backscatter values of-17 to -18 dB are caused by absorption of the radar signal in the lake bed. For ice that remains afloat all winter the ice-water interface and the tubular bubbles combine, presumably via an incoherent double-bounce mechanism, to cause maximum backscatter values of the order of -6 to -7 dB. The σ° saturates at -6 to -7 dB before maximum ice thickness and tubular bubble content are attained. A simple ice growth model suggests that the layer of ice with tubular bubbles need be only a few centimeters thick midway through the growth season to cause maximum backscatter from floating ice. During the spring thaw a previously unreported backscatter reversal is observed on the floating and grounded portions of the coastal lakes but not on the lakes farther inland. This reversal may be related to the ice surface topography and wetness plus the effects of a longer, cooler melt period by the coast. Time series of backscatter variations from shallow tundra lakes are a record of (1) the development of tubular bubbles in the ice and, by association, changes in the gas content of the underlying

  4. Structural and stratigraphic features and ERS 1 synthetic aperture radar backscatter characteristics of ice growing on shallow lakes in NW Alaska, winter 1991-1992

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Morris, K.; Weeks, W. F.; Wakabayashi, H.

    1994-01-01

    Changes in Earth Remote-Sensing Satellite (ERS) 1 C band synthetic aperture radar (SAR) backscatter intensity (sigma(exp 0)) from ice growing on shallow tundra lakes at three locations in NW Alaska are described. Ice core analysis shows that all lakes on the coast at Barrow the ice, whether floating or frozen to the bottom, includes an inclusion-free layer overlying a layer of ice with tubular bubbles oriented parallel to the direction of growth. The clear ice may also be overlain by a discontinuous layer of bubbly snow ice. Backscatter is low (-16 to -22 dB) at the time of initial ice formation, probably due to the specular nature of the upper and lower ice surfaces causing the radar pulse to be reflected away from the radar. As the ice thickens during the autumn, backscatter rises steadily. Once the ice freezes to the lake bottom, regardless of the presence of foward scattering tubular bubbles, low backscatter values of -17 to -18 dB are caused by absorption of the radar signal in the lake bed. For ice that remains afloat all winter the ice-water interface and the tubular bubbles combine, presumably via an incoherent double-bounce mechanism, to cause maximum backscatter values of the order of -6 to -7 dB. The sigma(exp 0) saturates at -6 to -7 dB before maximum ice thickness and tubular bubble content are attained. A simple ice growth model suggests that the layer of ice with tubular bubbles need be only a few centimeters thick midway through the growth season to cause maximum backscatter from floating ice. During the spring thaw a previously unreported backscatter reversal is observed on the floating and grounded portions of the coastal lakes but not on the lakes farther inland. This reversal may be related to the ice surface topography and wetness plus the effects of a longer, cooler melt period by the coast. Time series of backscatter variations from shallow tundra lakes are a record of (1) the development of tubular bubbles in the ice and, by association

  5. The disappearing of the largest lake in the Middle East: Geochemical clues for human impact on Urmia salt lake NW Iran

    NASA Astrophysics Data System (ADS)

    Sharifi, O.; Haeri-Ardakani, O.; Pourmand, A.

    2012-12-01

    The water level in Lake Urmia, the third largest saline lake on earth and the largest continental lake in the Middle East, has dropped by more than 9 m over the last two decades, with no signs of improvement in recent years. Urmia is a hypersaline shallow lake (average salinity ~200 ‰) located in a closed continental drainage basin in northwestern Iran, and is surrounded by a variety of rock formations, ranging in age from Precambrian metamorphic complexes to Holocene mud deposits. Lake sediments are composed of two major components; chemical-biochemical and clastic fractions. Based on grain size analysis of samples from 24 push-cores, silt-size particles dominate the lake's sediments with clay-bearing materials mostly present near the center of the lake. Sand-size particles are dominant in the northwest, where felsic to intermediate plutonic and metamorphic rocks are located in the proximity of the lake. The water of the Urmia Lake can be classified as Na-K-Cl-Mg-SO4 brine. Based on chemical analysis of conservative lithogenic elements (e.g., Ti, Si, Al, Ca) as well as redox-sensitive elements (e.g., Fe, K, Rb, Sr) in the clastic fraction of the lake's sediment, elemental distributions are reflective of regional geology. The main sources of ions to the lake are evaporite formations with minor contribution from igneous rocks. Ion concentrations in the northern part of the lake are nearly constant throughout the year while south-southeastern parts of the lake show variable annual ion concentration due to major fresh water inflows. Chemical analysis of the surface sediment samples for heavy metals (Ni, Cr, V and Hg) indicate moderate to high degrees of contamination in the affected areas, where Hg is the most abundant heavy metal. The highest concentrations of Hg (Normalized Enrichment Factor =6) are observed in the middle part of the lake, where intensive dredging and construction activities have taken place. In contrast, the lowest concentrations of Hg in

  6. Recent environmental changes in the shallow Lake Pamvotis (NW Greece): evidence from sedimentary organic matter, hydrocarbons, and stable isotopes.

    PubMed

    Daskalou, Victoria; Vreca, Polona; Muri, Gregor; Stalikas, Constantine

    2009-07-01

    Lake Pamvotis is a shallow Mediterranean lake located in northwestern Greece that has been recognized as an internationally important conservation site. Here, an unprecedented investigation was undertaken to obtain and evaluate data related to sedimentary organic matter, hydrocarbon content, and stable isotopes of Lake Pamvotis sediments, thus tracking the origin of organic inputs and providing a record of environmental status. The study revealed a distinct spatial distribution of polycyclic aromatic hydrocarbons (PAHs) with values between 34.7 and 1600 microg/kg and a rather uniform pattern for n-alkanes with concentrations falling below 41.4 microg/g. A significant contribution of an unresolved complex mixture indicated anthropogenic petroleum contamination. Further study of relevant indexes and geochemical biomarkers supported a mixed-source input of aliphatic hydrocarbons. With regard to PAHs, there was strong evidence that their dominant origin is pyrogenic. Finally, considerable excursion in delta(13)C(org) was attributed to changes in dissolved inorganic carbon accompanied by increased input of effluents and recycling of organic carbon within the lake, whereas the rise in isotopic composition of nitrogen was associated with agricultural runoff and sewage input from the town of Ioannina. PMID:18931963

  7. Cold active hydrolytic enzymes production by psychrotrophic Bacilli isolated from three sub-glacial lakes of NW Indian Himalayas.

    PubMed

    Yadav, Ajar Nath; Sachan, Shashwati Ghosh; Verma, Priyanka; Kaushik, Rajeev; Saxena, Anil Kumar

    2016-03-01

    The diversity of culturable, cold-active enzymes producing Bacilli was investigated from three sub-glacial lakes of north western Indian Himalayas. Amplified ribosomal DNA restriction analysis (ARDRA) using three restriction enzymes Alu I, Msp I, and Hae III led to the clustering of 136 Bacilli into 26, 23, and 22 clusters at 75% similarity index from Chandratal Lake, Dashair Lake, and Pangong Lake, respectively. Phylogenetic analysis based on 16S rRNA gene sequencing led to the identification of 35 Bacilli that could be grouped in seven families viz.: Bacillaceae (48%), Staphylococcaceae (14%), Bacillales incertae sedis (13%), Planococcaceae (12%), Paenibacillaceae (9%), Sporolactobacillaceae (3%), and Carnobacteriaceae (1%), which included twelve different genera Bacillus, Desemzia, Exiguobacterium, Jeotgalicoccus, Lysinibacillus, Paenibacillus, Planococcus, Pontibacillus, Sinobaca, Sporosarcina, Staphylococcus, and Virgibacillus. Based on their optimal temperature for growth, 35 Bacilli were grouped as psychrophilic (11 strains), psychrotrophic (17 strains), or psychrotolerant (7 strains), respectively. The representative isolates from each cluster were screened for cold-active enzyme activities. Amylase, β-glucosidase, pectinase, and protease activities at 4 °C were detected in more than 80% of the strains while approximately 40, 31, 23, 14, 11, and 9% of strains possessed cellulase, xylanase, β-galactosidase, laccase, chitinase, and lipase activity, respectively. Among 35 Bacilli, Bacillus amyloliquefaciens, Bacillus marisflavi, Exiguobacterium indicum, Paenibacillus terrae, Pontibacillus sp., Sporosarcina globispora, and Sporosarcina psychrophila were efficient producers of different cold-active enzymes. These cold-adapted Bacilli could play an important role in industrial and agricultural processes. PMID:26933936

  8. Paleohydrological and paleoclimatic oscillations during MIS3 revealed by multi-proxies from Balikun Lake, NW China

    NASA Astrophysics Data System (ADS)

    An, Chengbang; Zhao, Yongtao

    2016-04-01

    Multi-disciplinary analyses (sedimental, geochemical) of a sedimental core (BLK11A) recovered from the centre of the Balikun Lake, eastern Tienshan Mts., provide evidence of paleohydrology and its climatic indications in the arid western China during MIS3. The results suggested fairly high-frequency MIS3 interstadial oscillations and alternate change patterns among nearly fresh water and brackish water and hypersaline water during the ~30 ka. We also found that: 1) the evolutional process of the lake responds indicatively and quickly to the climate change on sub-orbital and millennial timescales, the onset of MIS3 interstadial is featured by abrupt increases in both bioproductivity and chemical weathering; 2) the appearance of the halite lithofacies indicates gradually cooling and drying trends during the middle to late MIS3, this deteriorated environment shrunk the lake area and weakened the vegetation cover as well as watershed chemical weathering; 3) Our new interpretations differ from the assumption that highest lake level and wettest conditions occurred during the late MIS3 from Tibetan Plateau and Inner Mongolia, while suggest that the climate in the Balikun region, even most of arid western China areas would have undergone a progressive aridification. The evolution of the paleohydrology and climate change of Balikun Basin may have a strong correlation with the high latitude summer insolation and the climate in North Atlantic.

  9. Impacts of climate and humans on the vegetation in NW Turkey: palynological insights from Lake Iznik since the Last Glacial

    NASA Astrophysics Data System (ADS)

    Miebach, A.; Niestrath, P.; Roeser, P.; Litt, T.

    2015-11-01

    The Marmara region in northwestern Turkey provides a unique opportunity for studying the vegetation history in response to climate changes and anthropogenic impacts because of its location between different climate and vegetation zones and its long settlement history. Geochemical and mineralogical investigations of the largest lake in the region, Lake Iznik, already registered climate related changes of the lake level and the lake mixing. However, a palynological investigation encompassing the Late Pleistocene to Middle Holocene was still missing. Here, we present the first pollen record of the last ca. 31 ka cal BP (calibrated kilo years before 1950) inferred from Lake Iznik sediments as an independent proxy for paleoecological reconstructions. Our study reveals that the vegetation in the Iznik area changed generally between steppe during glacial/stadial conditions, forest-steppe during interstadial conditions, and oak dominated mesic forest during interglacial conditions. Moreover, a pronounced succession of pioneer trees, cold temperate, warm temperate, and Mediterranean trees appeared since the Lateglacial. Rapid climate changes, which are reflected by vegetation changes, can be correlated with Dansgaard-Oeschger (DO) events such as DO-4, DO-3, and DO-1, the Younger Dryas, and probably also the 8.2 event. Since the mid-Holocene, the vegetation was influenced by anthropogenic activities. During early settlement phases, the distinction between climate-induced and human-induced changes of the vegetation is challenging. Still, evidence for human activities consolidates since the Early Bronze Age (ca. 4.8 ka cal BP): cultivated trees, crops, and secondary human indicator taxa appeared, and forests got cleared. Subsequent fluctuations between extensive agricultural use and regeneration of the natural vegetation become apparent.

  10. Paleo-climate and paleo-environment reconstruction based on a high-resolution, multi-proxy Holocene lake record from Lake Urmia (NW Iran)

    NASA Astrophysics Data System (ADS)

    Haghipour, Negar; Eglinton, Timothy; McIntyre, Cameron; Darvishi Khatooni, Javad; Hunziker, Daniela; mohammadi, Ali

    2016-04-01

    Lake Urmia, in northwest Iran, is the largest saline lake in the Middle East with a surface area of ~ 5000km2. Historical documents indicate its existence since at least 2000 years BC, and palynological investigation of a 100 m-long core suggest it contains a sedimentary record spanning the last 200 ka. Despite this potential as an archive of paleo-climate and paleo-environmental information, to date there has been no molecular organic geochemical investigation or precise dating of these sediments. We present lake sediment core data on both geochemical proxies and sediment lipid biomarkers on two cores form different part of the Lake. Each core has 10m length and covers Holocene time scale. The age model based on calibrated radiocarbon dates shows variation of sedimentation rates between early and middle Holocene and a sudden increase in late Holocene. This is interpreted as a sudden event and mass movement. Downcore results on bulk measurements (TOC, δ13C and C/N) give evidence for a warmer and wetter climates between 0.5 and 3 kyr BP. Phytoplankton biomarkers were most abundant in this period, indicating high phytoplankton productivity. Further gradual shift to cooler and drier episodes occur between 3.5 and 7Kyr Bp, decrease in phytoplankton productivity indicating cooler climate and show terrestrial signal. The coolest and drier conditions occurred between 7-10.3 Kyr BP. This is in agreement with Carbon and Hydrogen isotopic composition of n-alkonic acids.

  11. Warm Brine Lakes in Craters of Active Mud Volcanoes, Menes Caldera off NW Egypt: Evidence for Deep-Rooted Thermogenic Processes

    NASA Astrophysics Data System (ADS)

    Dupré, S.; Mascle, J.; Foucher, J. P.; Woodside, J. M.; Pierre, C.

    2015-12-01

    The Menes caldera is a fault-controlled depression (~8 km in diameter) at ~3,000 m water depth in the western province of the Nile deep-sea fan off NW Egypt, comprising seven mud volcanoes (MVs) of which two are active. Based on multichannel and chirp seismic data, temperature profiles, and high-resolution bathymetric data collected during several oceanographic expeditions, the present study investigates factors controlling mud volcano morphology, the geometry of feeder channels, and the origin of emitted fluids (Dupré et al. 2014). The active Cheops and Chephren mud volcanoes are 1,500 m wide with subcircular craters at their summits, about 250 m in diameter, generally a few tens of metres deep, and filled with methane-rich muddy brines with temperatures reaching 42 °C and 57 °C respectively. Deployments of CTDs and corers with attached temperature sensors tracked these warm temperatures down to almost 0.5 km depth below the brine lake surface at the Cheops mud volcano, in a feeder channel probably only a few tens of metres wide. Thermogenic processes involve the dissolution of Messinian evaporites by warm fluids likely sourced even deeper, i.e. 1.7 and 2.6 km below the seabed at the Cheops and Chephren MVs respectively, and which ascend along listric faults. Seepage activity appears broadly persistent since the initiation of mud volcanism in the Early Pliocene, possibly accompanied by lateral migration of feeder channels.

  12. Gravity anomaly at a Pleistocene lake bed in NW Alaska interpreted by analogy with Greenland's Lake Taserssauq and its floating ice tongue

    USGS Publications Warehouse

    Barnes, D.F.

    1987-01-01

    A possible example of a very deep glacial excavation is provided by a distinctive gravity low located at the front of a valley glacier that once flowed into glacial Lake Aniuk (formerly Lake Noatak) in the western Brooks Range. Geologic and geophysical data suggest that sediments or ice filling a glacially excavated valley are the most probable cause of the 30-50 mGal anomaly. Reasonable choices of geometric models and density contrasts indicate that the former excavation is now filled with a buried-ice thickness of 700 m or sediment thicknesses greater than 1 km. No direct evidence of efficient excavation was observed in Greenland, but efficient glacial erosion behind a floating polar ice tongue could explain the excavation that caused the Alaskan gravity anomaly. -from Author

  13. An INTIMATE Example: Into and out of the Younger Dryas at Lake Hämelsee, NW-Germany

    NASA Astrophysics Data System (ADS)

    de Bruijn, Renée; Engels, Stefan; Hoek, Wim Z.; Lane, Christine S.; Sachse, Dirk; Wagner-Cremer, Friederike

    2014-05-01

    Lake Hämelsee is a classical site with an excellent high-resolution record of Pleniglacial to Holocene climate and environment, contained in 18m of lacustrine sediments. At the centre of the lake, the Late Glacial interval consists of 2.7m of sapropelic and silty muds, that are mostly laminated (Merkt and Müller, QI 1999). In the framework of a summer school - 'An INTIMATE Example' - the lake was cored again, with the purpose of applying the latest techniques in palaeoclimatology and -ecology. Twenty international students and Early Stage Researchers (ESR's) from a wide range of backgrounds participated in lectures and field work and gained hands-on-experience with several proxies and techniques. Ongoing research by participants of the training school is focused on the timing and nature of the Allerød - Younger Dryas (YD) and YD - Preboreal transitions. Five short-term international exchange visits have provided opportunities for participants to learn and apply new techniques to the Hämelsee record, supervised by members of the INTIMATE network. A new age model will be constructed for the Late Glacial core section based on a combination of 14C-dates on macro-remains, varve chronology and tephrochronology. Tephrostratigraphic correlations will allow direct correlation of the record to both marine and ice core records from the North Atlantic region, as well as other European archives. Palaeoclimatic and -ecological research will include pollen-, chironomid-, LOI-, XRF-, lipid biomarker, stable isotope and GDGT-analysis. Temperature reconstructions will be made based on several of these proxies, providing a unique opportunity to compare independent reconstructions using material from a single record. Not only did the training school and subsequent research provide an excellent opportunity for ESR's to learn and work with international experts in the field - the collected data will also provide a high-resolution multi-proxy record of palaeoclimatology, -ecology and

  14. Geophysical, isotopic, and hydrogeochemical tools to identify potential impacts on coastal groundwater resources from Urmia hypersaline Lake, NW Iran.

    PubMed

    Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh; Kholghi, Majid

    2016-08-01

    Measurements of major ions, trace elements, water-stable isotopes, and geophysical soundings were made to examine the interaction between Urmia Aquifer (UA) and Urmia Lake (UL), northwest Iran. The poor correlation between sampling depth and Cl(-) concentrations indicated that the position of freshwater-saltwater interface is not uniformly distributed in the study area, and this was attributed to aquifer heterogeneities. The targeted coastal wells showed B/Cl and Br/Cl molar ratios in the range of 0.0022-2.43 and 0.00032-0.28, respectively. The base-exchange index (BEI) and saturation index (SI) calculations showed that the salinization process followed by cation-exchange reactions mainly controls changes in the chemical composition of groundwater. All groundwater samples are depleted with respect to δ(18)O (-11.71 to -9.4 ‰) and δD (-66.26 to -48.41 ‰). The δ(18)O and δD isotope ratios for surface and groundwater had a similar range and showed high deuterium excess (d-excess) (21.11 to 31.16 ‰). The high d-excess in water samples is because of incoming vapors from the UL mixed with an evaporated moisture flux from the Urmia mainland and incoming vapors from the west (i.e., Mediterranean Sea). Some saline samples with low B/Cl and Br/Cl ratios had depleted δ(18)O and δD. In this case, due to freshwater flushing, the drilled wells in the coastal playas and salty sediments could have more depleted isotopes, more Cl(-), and consequently smaller B/Cl and Br/Cl ratios. Moreover, the results of hydrochemical facies evolution (HFE) diagram showed that because of the existence fine-grained sediments saturated with high density saltwater in the coastal areas that act as a natural barrier, increasing the groundwater exploitation leads to movement of freshwaters from recharge zones in the western mountains not saltwater from UL. The highly permeable sediments at the junction of the rivers to the lake are characterized by low hydraulic gradient and high

  15. Geophysical, isotopic, and hydrogeochemical tools to identify potential impacts on coastal groundwater resources from Urmia hypersaline Lake, NW Iran.

    PubMed

    Amiri, Vahab; Nakhaei, Mohammad; Lak, Razyeh; Kholghi, Majid

    2016-08-01

    Measurements of major ions, trace elements, water-stable isotopes, and geophysical soundings were made to examine the interaction between Urmia Aquifer (UA) and Urmia Lake (UL), northwest Iran. The poor correlation between sampling depth and Cl(-) concentrations indicated that the position of freshwater-saltwater interface is not uniformly distributed in the study area, and this was attributed to aquifer heterogeneities. The targeted coastal wells showed B/Cl and Br/Cl molar ratios in the range of 0.0022-2.43 and 0.00032-0.28, respectively. The base-exchange index (BEI) and saturation index (SI) calculations showed that the salinization process followed by cation-exchange reactions mainly controls changes in the chemical composition of groundwater. All groundwater samples are depleted with respect to δ(18)O (-11.71 to -9.4 ‰) and δD (-66.26 to -48.41 ‰). The δ(18)O and δD isotope ratios for surface and groundwater had a similar range and showed high deuterium excess (d-excess) (21.11 to 31.16 ‰). The high d-excess in water samples is because of incoming vapors from the UL mixed with an evaporated moisture flux from the Urmia mainland and incoming vapors from the west (i.e., Mediterranean Sea). Some saline samples with low B/Cl and Br/Cl ratios had depleted δ(18)O and δD. In this case, due to freshwater flushing, the drilled wells in the coastal playas and salty sediments could have more depleted isotopes, more Cl(-), and consequently smaller B/Cl and Br/Cl ratios. Moreover, the results of hydrochemical facies evolution (HFE) diagram showed that because of the existence fine-grained sediments saturated with high density saltwater in the coastal areas that act as a natural barrier, increasing the groundwater exploitation leads to movement of freshwaters from recharge zones in the western mountains not saltwater from UL. The highly permeable sediments at the junction of the rivers to the lake are characterized by low hydraulic gradient and high

  16. The Dispersal of the 8.2 ka Lake Agassiz Drainage Waters Into the NW Atlantic: Working Hypothesis

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, C.; de Vernal, A.; Weaver, A.; Fisher, D. A.; Solignac, S.

    2004-12-01

    The so-called "8.2 ka event", often associated with the drainage of glacial Lake Agassiz through Hudson Strait into the Labrador Sea that occurred some 8.4 ka ago, has been "seen" in various types of records. Absent in the Antarctica ice records, it appears in some Arctic ice records but not others. It is clearly recorded in the GRIP and North GRIP records, although with distinct features (notably a reverse deuterium-excess trend, suggesting that a proximal source of moisture could be involved; V. Masson pers. com.). Several paleoclimate sequences from Western Europe depict highly variable climate oscillations that are often attributed to this event. Such oscillations generally differ in their duration (from less than 40 years up to several hundreds of years) and, in many cases, do not differ significantly from the subsequent climate oscillations of the Holocene. Elsewhere, continental evidence for a major climate event is often unclear or questionable. Most scientists evoke a collapse or a strong reduction in the rate of the Atlantic Meridional Overturning (AMO) as an explanation for their observations, thus linking the pulses of freshwater release, the thermohaline circulation (THC), and the atmospheric response that would have resulted in largely spread "climatic anomalies". Some model experiments seem to support this scenario, but they have not necessarily been run with realistic freshwater release rates or routes. Most however would not allow a short "THC-excursion" thus raising concern about a less than 40 yr-event as reported in some records. Therefore, some strong marine "evidence" for at least a reduction of the AMO is needed. Unfortunately, most marine records have a time resolution unsuitable to ascertain a short duration reduction of the AMO, and/or are smoothed due to benthic mixing, thus dampening high frequency signals into the stochastic noise. When reported in marine records from the North Atlantic, the presence of this 8.2 ka event seems generally

  17. Varved sediments of Lake Oeschinen, NW Alps: filling the gap in the flood frequency-precipitation relationship for the last millennium

    NASA Astrophysics Data System (ADS)

    Amann, Benjamin; Szidat, Sönke; Grosjean, Martin

    2016-04-01

    The global climate is warming, which is leading to changes in the hydrological cycle. What are the impacts of these climatic changes on the occurrence and magnitude of extreme flood events? Are these changes simultaneous or independent? These are key questions for future flood-risk predictions. In Europe, regional climate models do not show robust results for the future occurrence of precipitation extremes, which is mainly due to the difficulty in resolving precipitation events and the limited temporal coverage of instrumental data. To overcome this issue, considerable effort has been put forward by the paleoclimate community to produce millennial-long flood proxy records from natural archives. This has led to a more comprehensive understanding of flood events in relation to climate variability. However, while there is an increased consensus in the long-term flood-temperature relationship, still very little is known about the role of precipitation changes on flood frequency and magnitude. This is largely due to the lack of long-term and high-quality precipitation records. Here we present a millennial-long precipitation reconstruction together with a flood-frequency record obtained from the same natural paleoclimate archive. This allows, for the first time, the direct comparison between the two climate variables in the Alps. We used the varved (annually laminated) sediments of proglacial Lake Oeschinen (1580 m a.s.l., NW European Alps) to reconstruct warm season (MJJA) precipitation and summer flood frequency back to AD 884. Our results support recent findings from an increasing number of studies in the Swiss, German, French and Austrian Alps showing that floods were consistently more frequent during cool periods over the last Millennium. While the relationship between flood frequency and inferred moist climate has remained speculative, our precipitation reconstruction allows for a direct comparison and shows that flood frequency also increased during wetter

  18. High-levels of microplastic pollution in a large, remote, mountain lake.

    PubMed

    Free, Christopher M; Jensen, Olaf P; Mason, Sherri A; Eriksen, Marcus; Williamson, Nicholas J; Boldgiv, Bazartseren

    2014-08-15

    Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km(-2), Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics.

  19. High-levels of microplastic pollution in a large, remote, mountain lake.

    PubMed

    Free, Christopher M; Jensen, Olaf P; Mason, Sherri A; Eriksen, Marcus; Williamson, Nicholas J; Boldgiv, Bazartseren

    2014-08-15

    Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km(-2), Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics. PMID:24973278

  20. Simulating the decadal- to millennial-scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska

    NASA Astrophysics Data System (ADS)

    Kessler, M. A.; Plug, L. J.; Walter Anthony, K. M.

    2012-06-01

    Thermokarst lakes alter landscape topography and hydrology in widespread permafrost regions and mobilize significant permafrost carbon pools, including releasing methane (CH4) to the atmosphere. Despite this, the dynamics of lake evolution, permafrost thawing, and carbon mobilization are not well known. We present a 3-D numerical model of thermokarst lakes on organic-rich yedoma permafrost terrains with surface water flow and pooling naturally defining lakes that deepen, expand laterally, and drain due to talik formation, bank retreat, and both gradual and catastrophic drainage. We predict the 3-D pattern of microbial methane production within the talik over time. As a first model test and calibration, beginning with small protolakes, we simulated 10,000 years of evolution of Pear and Claudi lakes, two neighboring thermokarst features on the northern Seward Peninsula, Alaska. Simulated lakes approximated observed bathymetry, but results are sensitive to initial topography and soil ice content. Local topography caused markedly different dynamics for the two lakes. Pear expanded rapidly across low-relief topography, fully drained multiple times, and released little methane in later stages due to Pleistocene carbon depletion by the first and largest lake generation. Claudi grew slowly and continuously across high-relief topography, forming high subaerial banks; partial drainages left remnant horseshoe lakes that continued to expand into virgin yedoma, mobilizing carbon at roughly the same rate irrespective of lake drainage. The ˜2× discrepancy between simulated CH4 production and observed emission rates in Claudi likely results from misestimation of hot spot ebullition, labile carbon content, CH4:CO2 production ratio, or microbial CH4 oxidation.

  1. Lake

    ERIC Educational Resources Information Center

    Wien, Carol Anne

    2008-01-01

    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…

  2. Biomarker signatures in sediment cores of Lake Urmia (NW Iran): Potential implications for paleo-climate and paleo-environment reconstruction

    NASA Astrophysics Data System (ADS)

    Haghipour, Negar; Eglinton, Timothy Ian; McIntyre, Cameron; Darvishi Khatooni, Javad; Hunziker, Daniela; Mohammadi, Ali

    2015-04-01

    Lake Urmia, in northwest Iran, is the largest saline lake in the Middle East with a surface area of ~ 5000km2. Historical documents indicate its existence since at least 2000 years BC, and palynological investigation of a 100 m-long core suggest it contains a sedimentary record spanning the last 200 ka. Despite this potential as an archive of paleo-climate and paleo-environmental information, to date there has been no molecular organic geochemical investigation or precise dating of these sediments. As part of an exploratory study, we have analyzed material from 3 recently collected 8 m-long cores from the eastern, western and middle part of the lake, with the aim of gaining insight in to past depositional and environmental conditions from biomarker signatures preserved in Lake Urmia sediments. The main objectives are to 1) constrain major source(s) of organic matter and gain insights into carbon cycle and depositional processes from bulk isotopic (δ13Corg, 14Corg) and molecular information, 2) determine the applicability of molecular proxies (TEX86 index derived from glyceroldialkylglycerol tetraethers, GDGTs, and unsaturation index UK37 based on long chain alkenones) for paleo-temperature reconstruction and 3) reconstruct the paleo- vegetation and hydrology from compound-specific stable isotopes (δ13C and δD of n-alkanes). In select samples examined from the three cores, we find the hydrocarbon fractions are dominated by long-chain n-alkanes, with n-C29 and C31 as the dominant homologues in most of the samples. Based on the n-alkane distribution, we distinguish two main types; Type 1 mainly includes the samples deeper than ca 4 m (CPI= 10.2, ACL= 30), characteristic of a terrestrial higher plant source; Type 2 comprises mainly shallower samples (CPI =1.5, ACL = 27.3) which may suggest an increased contribution of aquatic plants. Preliminary GDGT analyses indicate low BIT values for most samples, which suggest little input of soil-derived branched-GDGTs. The

  3. Sediment record of environmental change at Lake Lop Nur (Xinjiang, NW China) from 13.0 to 5.6 cal ka BP

    NASA Astrophysics Data System (ADS)

    Wang, Jingzhong; Jia, Hongjuan

    2016-09-01

    Lake Lop Nur is located in the eastern part of the Tarim Basin in Xinjiang, northwestern China. A 220-cm-long sediment core was collected from the center of the ear-shaped depression forming the basin and dated with AMS14C. Grain size, total organic matter (TOC), total nitrogen (TN), and TOC/TN (C/N) analyses were used to reconstruct climatic conditions from 13.0 to 5.6 cal ka BP. The results showed five main climatic stages. Zone I (13.0-11.3 cal ka BP) was a wet-dry environment, whereas Zone II (11.3-8.9 cal ka BP) consisted of a primarily wet environment. Zone III (8.9-7.7 cal ka BP) was subdivided into Zone IIIa (8.9-8.2 cal ka BP) that indicated lake constriction and dry climate, and Zone IIIb (8.2-7.7 cal ka BP) in which the proxies indicated wet conditions. In Zone IV (7.7-6.6 cal ka BP), the climate presented a bit wet conditions. In Zone V (6.6-5.6 cal ka BP), abundant glauberite is present in the sediment and silt dominates the lithology; these results indicate the lake shrank and the overall climate was dry. Abrupt environmental events were also identified, including six dry events at 11.0, 10.5, 9.3, 8.6, 8.2, and 7.6 cal ka BP and one flood event from 7.8 to 7.7 cal ka BP in the Early-Middle Holocene.

  4. Significant Accommodation of NW-Directed Right Lateral Shear Across the Northern Walker Lane, Nevada by the Pyramid Lake Fault Zone

    NASA Astrophysics Data System (ADS)

    Briggs, R. W.; Wesnousky, S. G.

    2002-12-01

    Geodetic measurements indicate that 4-8 mm/year of northwest directed, right lateral shear is accumulating across the northern Walker Lane at the latitude of Reno, Nevada (Thatcher et al., 1999). The Pyramid Lake fault zone is located at the latitude of Reno within the northern Walker Lane. The northwest trending, right lateral fault exhibits features typical of strike slip faults, including laterally offset geomorphic features, opposite-facing scarps, and linear ridges and depressions. The fault zone is ideally oriented to accommodate northwest directed right lateral shear. Measurements of laterally offset geomorphic features, including channel thalwegs, channel banks, and prominent ridges are interpreted to show the fault slip rate is at minimum 1mm/yr and probably >=3 mm/yr during the latest Pleistocene and Holocene. Thus the Pyramid Lake fault zone appears to accommodate a significant portion (40-75%) of the geodetically measured strain at its latitude across the northern Walker Lane. Radiocarbon and tephra collected from trench exposures are placing limits on the recurrence and recency of rupture along the fault.

  5. Determination of Sinkholes with Different Geophysical Techniques; A Case Study in Yarımburgaz, Küçükçekmece Lake NW Istanbul, Turkey

    NASA Astrophysics Data System (ADS)

    Karabulut, Savas; Cengiz Cinku, Mualla; Tezel, Okan; Dedecan, Hasan; Oygo, Azat

    2016-04-01

    The Yarımburgaz cave which is located in the city of Istanbul, NW Turkey plays an important host to the first human culture and preserve significant archaeological and paleontological resources. The cave was formed as a result of a subterranean stream erosion on the limestones of the Eocene Kırklareli formation. It has been reported that a double cave with upper and lower entrance chambers exist, although no geophysical research was conducted to detect the cave's trunk passages and the extend of the sediment fill inside the cave. The aim of this study was to test the preferred order for detection the response to different geophysical methods applied on the cave. We therefore carried out an a series of geophysical study to determine the size, position, and depth of sinkholes inside the caves. Integrated methodological approaches including multichannel analysis of surface wave (MASW) 2- microtremor array method, 3-single station microtremor measurements, 4- electrical tomography (ET) measuruments and 5-microgravity imaging showed that the geophysical response was succesfully applied. Based upon the flow-chart we concluded that the microgravity survey should be applied as a first step to detect the air-filled void and the geometry of the cave. The electric tomography method was well applied showing high resistivity values across the voids. The surface wave method showed that the low-velocity zones are detected in various locations of the cave. In addition we the results of MASW and ReMi methods showed clearly the density variation in the lateral direction. Fundamental frequency value above void decraese according the properties of geological units in lateral directional, especially when they are engineering rock like limestone.

  6. A 2400-year record of abrupt climate change from Almalou Crate Lake in NW Iran: Investigating the potential influence of solar variability on the climate of West Asia during late Holocene

    NASA Astrophysics Data System (ADS)

    Sharifi, A.; Pourmand, A.; Canuel, E. A.; Naderi Beni, A.; Lahijani, H. A.

    2013-12-01

    The Mediterranean climate of northwest Iran is influenced by mid-latitude Westerlies and the winter expansion of the Siberian Anticyclone. Given the significance of this region in development of human civilizations, high-resolution reconstructions of abrupt climate change are of particular interest during the Holocene. Almalou Crater Lake sustains the growth of plants inside the crater of a dormant volcanic cone on the eastern flank of the Sahand volcanic district in NW Iran. At an elevation of 2491 m.a.s.l., the crater is exclusively fed by rainfall during the spring and fall and snowfall during the winter. Preservation of organic matter within the crater can potentially record changes in atmospheric deposition and paleo-environmental conditions over this region. To reconstruct changes in atmospheric aeolian input, we present a high-resolution (sub-decadal) multi-proxy record of climate variability during the last 2400 years from a 3-m peat core recovered from the crater peat bog. Radiocarbon dates of eight samples along the core show a nearly constant rate of accumulation (7.7 mm yr-1, R2=0.98) since 2404×25 cal yr BP. Downcore X-ray fluorescence measurements of selected conservative lithogenic elements (e.g., Al, Si, and Ti) as well as redox-sensitive elements (e.g., Fe and Rb) at 10 mm intervals reveal several periods of elevated abundances related to enhanced atmospheric dust deposition. The co-variations between relative abundances of conservative and redox-sensitive elements as a function of time show significant agreement and attest to the ombrotrophic nature of the entire record. Intervals of enhanced dust deposition inferred from XRF data reveal three short episodes (~ 150-y) at 450-600, 1150-1300, and 1400-1550 cal yr BP, and one prolonged period (500 y) of dust accumulation from 1600 to 2070 cal yr BP. These intervals of high atmospheric dust coincide with historical records of drought and famine in Iran since 2000 BP. Wavelet analysis conducted on the

  7. Generation of an Archaean H/sub 2/O-CO/sub 2/ fluid enriched in Au, W and Mo by fractional crystallization in the Mink Lake intrusion, NW Ontario

    SciTech Connect

    Burrows, D.R.; Spooner, E.T.C.

    1985-01-01

    Fractional crystallization (FC) of the post-tectonic trondhjemitic Mink Lake intrusion in NW Ontario resulted in a residual H/sub 2/O-CO/sub 2/ low salinity fluid with an isotopic composition (delta /sup 13/C/sub cc/ x = -3.3 per thousand +/- 0.4 per thousand (1s), delta/sup 18/O/sub cc/ + 10.7 to 15.9 per thousand, deltaD/sub FI/ -70 +/- 9 per thousand (1s) and delta /sup 34/S/sub py/ +0.4 to +2.90 per thousand) compatible with magmatic derivation and extremely similar to that in vein quartz-carbonate-pyrite +/- scheelite, +/- tourmaline, +/- MoS/sub 2/ +/- telluride systems characteristic of major Archaean lode gold deposits. Inward FC of the granodiorite magma (69-71% SiO/sub 2/, Na/sub 2/O/K/sub 2/O = 1.6-3.9), as indicated by trace and REE data, produced a sequence of microgranites and aplitic dykes with mean values by INNA (n=10) for Au of 2.3ppb, Mo = 22ppm and W = 7.3ppm as compared to mean background values in the granodiorite of Au <1ppb, Mo less than or equal to 1ppm with W less than or equal to 3.7ppm (n=4). The latest aplites are observed to coexist with a H/sub 2/O-CO/sub 2/ mixture and are characterized by carbonate alteration selvages and minor MoS/sub 2/. Subsequent separation of the H/sub 2/O-CO/sub 2/ fluid and interaction with an otherwise fresh granodiorite within the already solidified southern margin, produced MoS/sub 2/ mineralized sub-horizontal quartz veins and larger tabular lenses of carbonate alteration without internal veining. Such zones are anomalously enriched (n=10) in Au (anti x = 153 pbb, range 2-570ppb) Mo (anti x 660ppm, range 1-2500ppm and W (anti x = 61 ppm, range 23-95 ppm).

  8. A Holocene climate record from palaeolakes in NW India

    NASA Astrophysics Data System (ADS)

    Dixit, Y.; Hodell, D. A.; Petrie, C.

    2011-12-01

    The plains of NW India encompasses arid, semi-arid to sub-humid zones and archaeological research indicate this region was intensively settled by the Indus Valley Civilization. The precise climatological and environmental history of this region during the Holocene period remain largely unknown. We present high-resolution isotope proxy records of local palaeoclimate change from lacustrine deposits in two different climatic zones from west to east; Palaeo-lake Riwasa in the semi-arid and paleo-lake Kotla Dahar in the sub-humid region in Haryana plains, India. The oxygen isotope record from palaeolake Riwasa indicates the inception of wet climate conditions and establishment of a deep, permanent lake in the basin at ~8870 14C yr BP, coinciding approximately with the early Holocene maximum in the Indian monsoon. A major desiccation event occurs after ~7000 14C yr BP. Our results from palaeolake Riwasa indicate that the permanent deep-water lake and major desiccation event in semi-arid region pre-dated the urban phase of the Indus Civilization. Palaeolake Kotla Dahar is located further east than Riwasa in the sub-humid zone, and receives 500-700mm rainfall. Calcium carbonate percent of bulk sediments from Kotla Dahar increases down section to a maximum of 72%, indicating the presence of a deep carbonate marl lake. Oxygen isotopes are currently being measured on gastropod and ostracod shells and radiocarbon dates are being obtained from this section. We speculate that the oxygen isotope record from Kotla Dahar may provide critical climate data for the period between 5000-3500 BP, the period of Harappan Urbanism. Our study of palaeo-lakes Riwasa and Kotla Dahar constitute the first oxygen isotope records from the plains of NW India to interpret the palaeoclimate history of this region.

  9. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This quarterly publication of the State Historical Society of Iowa features articles and activities for elementary school students. This summer issue focuses on the topic of lake life. The issue includes the following features: (1) "Where the Lakes Are Map"; (2) "Letter from the Lake"; (3) "Lake People"; (4) "Spirit Lake"; (5) "Lake Manawa"; (6)…

  10. Fish Lake, Utah - shallow seismic investigation of a lake-filled high-altitude graben

    NASA Astrophysics Data System (ADS)

    Harris, M. S.; Oliviera-Manna, M.; Bailey, C.; Marchetti, D. W.; Brunelle, A.; Abbott, M. B.; Larsen, D. J.; Stoner, J. S.; Grimm, E. C.; Donovan, J.; Anderson, L.; Power, M. J.; Chavez, V.; Carter, V.; Hart, I.

    2015-12-01

    Fish Lake formed in a portion of the 20-km x 2.5-km wide NE-SW trending graben within the High Plateaus of Utah, on the border between the Basin and Range to the west and the Canyon Lands east. This presentation focuses on the shallow seismic stratigraphic architecture of the lake. Marchetti et al. (this meeting) focuses details of a shallow core collected in 2014. With a lake surface at 2700m, avg. depth of 27m (max 37m), the lake is flanked NW by a 15° slope up to a formerly glaciated Hightop plateau (3545m) and is bound to the SE by a 30° NW facing slope off the Mytoge crest (3050m). The drainage basin is 74 km2 with ~75% of the catchment draining the Hightop from four distinct streams. Pelican Canyon (glaciated) and Doctor Canyon (unglaciated) provide most drainage into the basin, with Bowery and Twin creeks draining only the slope. These streams flow through organic-rich meadows at the edge of the lake. Only one small stream drains NW into the lake from the small Crater Lakes graben (2850m) off the Mytoge. Bathymetric surveys in the lake highlight a submerged moraine to the NE, a gently sloping bottom that reaches maximum depth off the steep wall to the SE, and small delta-form features off each of the creeks on the NW edge. Chirp seismic surveys (2-16 kHz) consistently penetrate the upper 40-m (up to ~55m). The oldest visible reflectors rise into the submerged moraine to the NE, ending in a complex set of truncated and discontinuous beds eluding to soft sediment push at the front of the glacier. Along the edge near the creeks to the NW, multiple sets of downlapping reflectors, gas pockets, and chaotic beds with lobate tops define what we interpret as deltaic deposition, possible lower lake levels with marsh systems, and slope failures. The majority of the lake is underlain by flat-lying reflectors that bound sedimentary packages spanning the entirety of the basin interior. The uppermost layers have recently been cored where seismic reflectors are continuous

  11. NW CSC annual report fiscal year 2013

    USGS Publications Warehouse

    Bisbal, Gustavo A.

    2013-01-01

    The Northwest Climate Science Center (NW CSC) was established in 2010 as one of eight regional Climate Science Centers created by the Department of the Interior (DOI). The NW CSC encompasses Washing-ton, Oregon, Idaho, and western Montana and has overlapping boundaries with three Landscape Conservation Cooperatives (LCCs): the Great Northern, the Great Basin, and the North Pacific. With guidance from its Executive Stakeholder Advisory Committee (ESAC), the NW CSC and its partner LCCs are addressing the highest priority regional climate science needs of Northwest natural and cultural resource managers. Climate Science Centers tap into the scientific expertise of both the U.S. Geological Survey (USGS) and academic institutions. The NW CSC is supported by an academic consortium with the capacity to generate climate science and tools in a coordinated fashion, serving stakeholders across the Northwest region. This consortium is primarily represented by Oregon State University (OSU), the University of Id-ho (UI), and the University of Washington (UW). The academic consortium and USGS provide capabilities in climate science, ecology, impacts and vulnerability assessment, modeling, adaptation planning, and advanced information technology, all necessary to address and respond to climate change in the Northwest. University members also recruit and train graduate students and early-career scientists. This Annual Report summarizes progress for the goals set out in the NW CSC Strategic Plan for 2012-2015 (http://www.doi.gov/csc/northwest/upload/Northwest-CSC-Strategic-Plan.cfm) and the NW CSC Work-plan for Fiscal Year (FY) 2013 (October 1, 2012 through September 30, 2013). The report follows the structure of the Strategic Plan, which describes the five core services (Executive, Science, Data, Communications, and Education and Training) provided by the NW CSC in support of the stated vision: Our Vision: To become nationally recognized as a best-practice model for the provision

  12. 24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. OLD TIOGA ROAD VIEW, NOW MAY LAKE ROAD , AT SNOW FLAT. MOUNT HOFFMAN AT CENTER REAR. LOOKING NW. GIS: N-37 49 34.6 / W-119 29 58.2 - Tioga Road, Between Crane Flat & Tioga Pass, Yosemite Village, Mariposa County, CA

  13. The Morphometry of Lake Palmas, a Deep Natural Lake in Brazil

    PubMed Central

    Barroso, Gilberto F.; Gonçalves, Monica A.; Garcia, Fábio da C.

    2014-01-01

    Lake Palmas (A = 10.3km2) is located in the Lower Doce River Valley (LDRV), on the southeastern coast of Brazil. The Lake District of the LDRV includes 90 lakes, whose basic geomorphology is associated with the alluvial valleys of the Barreiras Formation (Cenozoic, Neogene) and with the Holocene coastal plain. This study aimed to investigate the relationship of morphometry and thermal pattern of a LDRV deep lake, Lake Palmas. A bathymetric survey carried out in 2011 and the analysis of hydrographic and wind data with a geographic information system allowed the calculation of several metrics of lake morphometry. The vertical profiling of physical and chemical variables in the water column during the wet/warm and dry/mild cold seasons of 2011 to 2013 has furnished a better understanding of the influence of the lake morphometry on its structure and function. The overdeepened basin has a subrectangular elongated shape and is aligned in a NW-SE direction in an alluvial valley with a maximum depth (Zmax) of 50.7m, a volume of 2.2×108 m3 (0.22km3) and a mean depth (Zmv) of 21.4m. These metrics suggest Lake Palmas as the deepest natural lake in Brazil. Water column profiling has indicated strong physical and chemical stratification during the wet/warm season, with a hypoxic/anoxic layer occupying one-half of the lake volume. The warm monomictic pattern of Lake Palmas, which is in an accordance to deep tropical lakes, is determined by water column mixing during the dry and mild cold season, especially under the influence of a high effective fetch associated with the incidence of cold fronts. Lake Palmas has a very long theoretical retention time, with a mean of 19.4 years. The changes observed in the hydrological flows of the tributary rivers may disturb the ecological resilience of Lake Palmas. PMID:25406062

  14. The morphometry of Lake Palmas, a deep natural lake in Brazil.

    PubMed

    Barroso, Gilberto F; Gonçalves, Monica A; Garcia, Fábio da C

    2014-01-01

    Lake Palmas (A = 10.3km2) is located in the Lower Doce River Valley (LDRV), on the southeastern coast of Brazil. The Lake District of the LDRV includes 90 lakes, whose basic geomorphology is associated with the alluvial valleys of the Barreiras Formation (Cenozoic, Neogene) and with the Holocene coastal plain. This study aimed to investigate the relationship of morphometry and thermal pattern of a LDRV deep lake, Lake Palmas. A bathymetric survey carried out in 2011 and the analysis of hydrographic and wind data with a geographic information system allowed the calculation of several metrics of lake morphometry. The vertical profiling of physical and chemical variables in the water column during the wet/warm and dry/mild cold seasons of 2011 to 2013 has furnished a better understanding of the influence of the lake morphometry on its structure and function. The overdeepened basin has a subrectangular elongated shape and is aligned in a NW-SE direction in an alluvial valley with a maximum depth (Zmax) of 50.7 m, a volume of 2.2×10(8) m3 (0.22 km3) and a mean depth (Zmv) of 21.4m. These metrics suggest Lake Palmas as the deepest natural lake in Brazil. Water column profiling has indicated strong physical and chemical stratification during the wet/warm season, with a hypoxic/anoxic layer occupying one-half of the lake volume. The warm monomictic pattern of Lake Palmas, which is in an accordance to deep tropical lakes, is determined by water column mixing during the dry and mild cold season, especially under the influence of a high effective fetch associated with the incidence of cold fronts. Lake Palmas has a very long theoretical retention time, with a mean of 19.4 years. The changes observed in the hydrological flows of the tributary rivers may disturb the ecological resilience of Lake Palmas. PMID:25406062

  15. Lake Eyre

    Atmospheric Science Data Center

    2013-04-16

    ...   View Larger Image Lake Eyre is a large salt lake situated between two deserts in one of Australia's driest regions. ... the effect of sunglint at the nadir camera view angle. Dry, salt encrusted parts of the lake appear bright white or gray. Purple areas have ...

  16. Glacier-induced Hazards in the Trans-Himalaya of Ladakh (NW-India)

    NASA Astrophysics Data System (ADS)

    Schmidt, Susanne; Dame, Juliane; Nüsser, Marcus

    2016-04-01

    Glaciers are important water resources for irrigated crop cultivation in the semi-arid Trans-Himalaya of Ladakh (NW-India). Due to global warming, many glaciers of South Asia have retreated over the last century and further ice loss will threaten local livelihoods in the long run. In the short term, an increase of flood events caused by melting glaciers and permafrost is expected for the Himalayan region. Beside large catastrophic events, small outburst floods are 'more' regularly reported for various parts of the region. This also holds true for the Trans-Himalayan region of Ladakh, where small glaciers exist at high altitudes. Caused by glacier retreat, a number of proglacial lakes have been formed, most of them dammed by ice filled moraines. The potential risk of these lakes is shown by recent reports on glacial lake outburst flood in the villages Nidder in October 2010 and Gya in August 2014. The 2014 flood destroyed several agricultural terraces, a new concrete bridge and two houses. Own remote sensing analyses shows the increase of a moraine dammed proglacial lake in the upper catchment area, which grew from about 0.03 to 0.08 km2 between 1969 and 2014. Because of the relatively stable altitude of the lake level, one can assume that the flood was caused by a piping process, initiated by melted ice bodies in the moraine. Already in the 1990s a small GLOF was observed in the village, which destroyed some fields. As in 2014, the lake was not completely spilled and a short-term decrease of the lake area is detectable in remote sensing data. Thus, further GLOF-events can be expected for the future. Beside physical risk factors, population growth and new infrastructure development along the streams and valleys increases potential damages of floods. Therefore, investigations are required to estimate the risks of these small glacial lakes and the potential flood effected area for the case study of Gya as well as for the whole region of Ladakh. Remote sensing data are

  17. 9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NW FROM EAST BANK OF SCHUYLKILL RIVER. - Philadelphia & Reading Railroad, Schuylkill River Viaduct, Spanning Schuylkill River, southeast of Roosevelt Boulevard Bridge, Philadelphia, Philadelphia County, PA

  18. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

    article title:  Lake Constance, Europe     View ... This Multi-angle Imaging SpectroRadiometer (MISR) image of Lake Constance covers an area measuring 355 kilometers x 287 kilometers, and ... wastewater and fertilizers. This leads to overproduction of algae and aquatic plants, exhaustion of available oxygen, loss of some fish ...

  19. Holocene versus modern catchment erosion rates at 300 MW Baspa II hydroelectric power plant (India, NW Himalaya)

    NASA Astrophysics Data System (ADS)

    Draganits, Erich; Gier, Susanne; Hofmann, Christa-Ch.; Janda, Christoph; Bookhagen, Bodo; Grasemann, Bernhard

    2014-08-01

    300 MW Baspa II is India's largest private hydroelectric facility, located at the Baspa River which is an important left-hand tributary to the Sutlej River in the NW Himalaya (India). In this valley the Sangla palaeo-lake has been dammed around 8200 yr BP behind a rock-avalanche dam and Baspa II is located exactly on top of this palaeo-lake. This special location represents a very rare possibility to evaluate the short-term, river load and hydrological parameters measured during the planning and operational stages of Baspa II with the long-term parameters gained from the palaeo-lake sediments from the catchment. Sedimentological and geomorphological investigations of the lacustrine sediments have been used to reconstruct environmental changes during >2500 years of its existence. The Mid-Holocene erosion rates of the Baspa catchment estimated from the volume and duration of deposition of the exposed lake sediments are at 0.7-1.0 mm yr-1, almost identical with the modern erosion rates calculated from river gauge data from Baspa II. Several charcoal layers and charcoal pieces from the uppermost palaeo-lake levels around 5000 cal yr BP might be related to woodland clearance and they possibly represent one of the oldest evidences for human presence in the Baspa Valley during Neolithic time.

  20. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao )

    1996-01-01

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  1. Formation and distribution of coal measure-derived hydrocarbon accumulation in NW China

    SciTech Connect

    Wenxhi Zhao; Yan Zhang; Dafeng Xu; Changyi Zhao

    1996-12-31

    This study recognizes that the following conditions are necessary for the Jurassic coal measure-derived oil and gas fields in NW China: (1) The Jurassic original basins, which were dominated by lacustrine to low-positional swamp environments, should exist to accept coal-measure related sediments, (2) the original depositional settings were characterized by low and gentle depressions and humid climate where oil-prone organic materials accumulated, (3) the development of the subsequent basins and successive sedimentation should occur on the Jurassic original basins, which are necessary to keep the coal measure source rocks progressively maturing, and, (4) a certain degree of tectonic compression took place soon after the maturation of source rocks, which provided the driving force for the effective expulsion of oil and gas from coal measures. Most of the coal measure-derived oil & gas fields in NW China are horizontally distributed along the inner side of lake strandlines. They occur vertically above or below the threshold of maturation. Owing to the sharp variations of lithology and facies in coal measures, the lithologies and hydrocarbon compositions of oil and gas reservoirs play a significant role in the oil and gas accumulations of the coal measures sequences.

  2. Geomorphological analysis of the drainage system on the active convergent system in Azerbaijan, NW Iran

    NASA Astrophysics Data System (ADS)

    Kaveh Firouz, Amaneh; Burg, Jean-Pierre; Giachetta, Emanuele

    2016-04-01

    Rivers are important landforms to reconstruct recent tectonic history because they are sensitive to surface movements, especially uplift and tilting. The most important drainage basins of NW Iran are, from north to south, the Arax River, the Urmia Lake and the Ghezel Ozan River catchment. The morphology of the two adjacent catchments draining into the Caspian Sea, the Arax and Ghezel Ozan were studied to better understand the active tectonics and the effect of fault activity on morphology and erosion rate of NW Iran. We performed a quantitative analysis of channel steepness and concavity, from slope-area plots calculated from digital elevation model. This information has been combined with GPS velocity vectors and seismicity. Both catchments developed under uniform climate conditions. Results show that the two rivers are in morphological disequilibrium; they exhibit profiles with prominent convexities and knickpoints. The Arax River shows higher channel steepness and concavity index in downstream part of the profile. Distribution of knickpoints show scattered elevation between 700m and 3000m. GPS rates display shortening 10 ± 2 mma‑1 and 14 ± 2 mma‑1 in upstream and downstream, respectively. The river profiles of Ghezel Ozan River and its tributaries reveal more disequilibrium downstream where channel steepness and concavity index are higher than upstream. Most knickpoints occur between 1000m and 2000m. The amount of shortening by GPS measurement changes from upstream 13 ± 2 mma‑1to downstream 14 ± 2 mma‑1. Recorded earthquakes, such as Rudbar earthquake (Mw=7.3, 1990), are more frequent downstream. The Urmia Lake is surrounded by many small and large catchments. Only major catchments were considered for the analysis. One of the most active faults, the north Tabriz fault, corresponds to a major knickpoints on the Talkhe rud River. Concordance between river profile analysis, GPS and seismotectonic records suggests that the characteristics of the river

  3. Geomorphological analysis of the drainage system on the active convergent system in Azerbaijan, NW Iran

    NASA Astrophysics Data System (ADS)

    Kaveh Firouz, Amaneh; Burg, Jean-Pierre; Giachetta, Emanuele

    2016-04-01

    Rivers are important landforms to reconstruct recent tectonic history because they are sensitive to surface movements, especially uplift and tilting. The most important drainage basins of NW Iran are, from north to south, the Arax River, the Urmia Lake and the Ghezel Ozan River catchment. The morphology of the two adjacent catchments draining into the Caspian Sea, the Arax and Ghezel Ozan were studied to better understand the active tectonics and the effect of fault activity on morphology and erosion rate of NW Iran. We performed a quantitative analysis of channel steepness and concavity, from slope-area plots calculated from digital elevation model. This information has been combined with GPS velocity vectors and seismicity. Both catchments developed under uniform climate conditions. Results show that the two rivers are in morphological disequilibrium; they exhibit profiles with prominent convexities and knickpoints. The Arax River shows higher channel steepness and concavity index in downstream part of the profile. Distribution of knickpoints show scattered elevation between 700m and 3000m. GPS rates display shortening 10 ± 2 mma-1 and 14 ± 2 mma-1 in upstream and downstream, respectively. The river profiles of Ghezel Ozan River and its tributaries reveal more disequilibrium downstream where channel steepness and concavity index are higher than upstream. Most knickpoints occur between 1000m and 2000m. The amount of shortening by GPS measurement changes from upstream 13 ± 2 mma-1to downstream 14 ± 2 mma-1. Recorded earthquakes, such as Rudbar earthquake (Mw=7.3, 1990), are more frequent downstream. The Urmia Lake is surrounded by many small and large catchments. Only major catchments were considered for the analysis. One of the most active faults, the north Tabriz fault, corresponds to a major knickpoints on the Talkhe rud River. Concordance between river profile analysis, GPS and seismotectonic records suggests that the characteristics of the river profiles

  4. Principles of lake sedimentology

    SciTech Connect

    Janasson, L.

    1983-01-01

    This book presents a comprehensive outline on the basic sedimentological principles for lakes, and focuses on environmental aspects and matters related to lake management and control-on lake ecology rather than lake geology. This is a guide for those who plan, perform and evaluate lake sedimentological investigations. Contents abridged: Lake types and sediment types. Sedimentation in lakes and water dynamics. Lake bottom dynamics. Sediment dynamics and sediment age. Sediments in aquatic pollution control programmes. Subject index.

  5. 4. Water treatment plant, view to NW, berm in foreground ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Water treatment plant, view to NW, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  6. 2. Oblique view of north corner shows mostly NW side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oblique view of north corner shows mostly NW side and how stack connects to NE side of building. - Pacific Creosoting Plant, Boiler Building, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  7. 10. Side view of cane mill looking NW with steam ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Side view of cane mill looking NW with steam engine in background. - Hacienda Azucarera La Esperanza, Steam Engine & Mill, 2.65 Mi. N of PR Rt. 2 Bridge over Manati River, Manati, Manati Municipio, PR

  8. 3. James Cant Ranch, view from NW showing Feed Storage ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. James Cant Ranch, view from NW showing Feed Storage Shed and Chicken Coop (in foreground), Barn, and Watchman's Hut - Cant Ranch, East side of State Route 19, North of U.S. 26, Dayville, Grant County, OR

  9. 8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. August, 1971. SECOND FLOOR LOOKING NW. EVAPORATOR UNITS USED IN SEQUENCE TO REDUCE OR CONCENTRATE BEET JUICE. - Utah Sugar Company, Garland Beet Sugar Refinery, Factory Street, Garland, Box Elder County, UT

  10. 16. View looking NW from warehouse rooftop on Water Street ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. View looking NW from warehouse rooftop on Water Street in Brooklyn. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  11. 64. Detail view looking NW at masonry approach arches on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    64. Detail view looking NW at masonry approach arches on the Brooklyn side. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  12. 53. View looking NW showing underside of deck of Brooklyn ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. View looking NW showing underside of deck of Brooklyn side span. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  13. 11. Looking NW at the underside of the structure. Note ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Looking NW at the underside of the structure. Note the transverse floor beams, the longitudinal stringers supporting the timber deck, and the metal strap diagonal bracing. - Beachside Avenue Bridge, Westport, Fairfield County, CT

  14. 1. AERIAL VIEW FROM SE LOOKING NW, SHOWING BRIDGE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW FROM SE LOOKING NW, SHOWING BRIDGE AND SITE CONTEXT - Slates' Mill Bridge, Township Road 439 spanning South Branch of Tunkhannock Creek in Benton Township, Dalton, Lackawanna County, PA

  15. Perspective view NW by 310. Note the concrete pier extending ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Perspective view NW by 310. Note the concrete pier extending from the bridge in the foreground. This way to allow maximum water flow during floods and rainy periods. - Weaverland Bridge, Quarry Road spanning Conestoga Creek, Terre Hill, Lancaster County, PA

  16. 35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. PRATER GRADE ROAD VIEW, FACING NW. NOTE WEATHERING STEEL RAIL AND ROAD CUT IN DISTANCE. MONTEZUMA VALLEY OVERLOOK IS JUST TO RIGHT OF DISTANT ROAD CUT. - Mesa Verde National Park Main Entrance Road, Cortez, Montezuma County, CO

  17. 2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. Philadelphia ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING NW, WITH READING DEPOT IN BACKGROUND. - Philadelphia & Reading Railroad, Pedestrian Suspension Bridge, Foot of Sixth Street at Schuylkill River (formerly spanned Philadelphia & Reading main line at Reading Depot), Reading, Berks County, PA

  18. 2. Photocopy of c. 1906 photograph looking NW at water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of c. 1906 photograph looking NW at water tower with mill pond and pump house in right center foreground; fuel oil storage tank in right background. - Laurel Valley Sugar Plantation, State Route 308, Thibodaux, Lafourche Parish, LA

  19. Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain.

    PubMed

    Sanchís, J; Sánchez-Andrade, R; Macchi, M I; Piñeiro, P; Suárez, J L; Cazapal-Monteiro, C; Maldini, G; Venzal, J M; Paz-Silva, A; Arias, M S

    2013-01-16

    The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors. In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR=3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR=3), the youngest bovines (<2.5 years) and dairy cattle (Friesians). Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5-7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years. It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.

  20. Geology of the Naturita NW quadrangle, Colorado

    USGS Publications Warehouse

    Cater, Fred W.; Vogel, J.D.

    1953-01-01

    The Naturita NW quadrangle is one of eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles were mapped by the U.S. Geological Survey on behalf of the U.S. Atomic Energy Commission as part of a comprehensive study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through an arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The ore consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear ro be related to certain sedimentary structures in sandstones of favorable composition.

  1. Lake Powell

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001.

    The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. NW-MILO Acoustic Data Collection

    SciTech Connect

    Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.; Jones, Mark E.

    2010-02-17

    There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight of Juan de Fuca, which contains part of the border between the U.S. and Canada. Table 1 lists the specific components used for the NW-MILO system. The acoustic sensor is a hydrophone permanently deployed at a mean depth of about 3 meters. In addition to a hydrophone, the other sensors in the system are a marine radar, an electro-optical (EO) camera and an infra-red (IR) camera. The radar is integrated with a vessel tracking system (VTS) that provides position, speed and heading information. The data from all the sensors is recorded and saved to a central server. The data has been validated in terms of its usability for characterizing the

  3. Land-Sea Correlation of Holocene Records in NW Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Gonzalez-Alvare, R.; Costas, S.; Bernardez, P.; Frances, G.; Alejo, I.

    2005-12-01

    Holocene climate fluctuations in the temperate region of the Northeast Atlantic have been established by comparing marine and terrestrial proxies. This work is based on suction-cores collected in the Cies Islands lagoon (NW Spain) and vibro-cores from the adjacent continental shelf. The lower Holocene marine record (9400-7000 yr BP) consists on sandy transgressive facies overlying fluvial Pleistocene deposits. During this time the continental shelf was dominated by high energy processes linked to the progressive and fast sea level rise. The rate of sea level rise sharply decelerated at 7000 yr BP and a high productive marine environment was fully established, as revealed by planktonic foraminifera assemblages and biogeochemical markers. In the terrestrial areas, peat deposits were formed beginning around 6000 yr BP in the deeper parts of the paleo-relief that was developed above the granitic basement. The peat was deposited in a fresh-water shallow coastal lake under warm and humid conditions that are brought about by prevailing SW winds. From 4800 yr BP, a progressive rainfall decrease provoked the lowering of the lake level and a weaker fluvial influence on the adjacent shelf. The prevailing eastern winds caused significantly drier conditions between 4000 and 3200 yr BP. During this period the coastal lake dried and the peat layer was covered by aeolian deposits. At the continental shelf a strong stratification of the water column induced a fall in the productivity. The end of this period is marked by the increase of storm regimes caused by a shift to prevailing SW winds. The last 3000 years are characterized by humid and warm conditions, and the enhancement of upwelling regime and terrestrial sediment supply. In Cies Islands, a sand barrier-lagoon complex was developed as a consequence of both the sea level rise and the inundation of the lower areas in the island.

  4. Ancient lakes on Mars?

    NASA Technical Reports Server (NTRS)

    Goldspiel, J. M.; Squyres, S. W.

    1989-01-01

    The valley systems in Mars' ancient cratered terrain provide strong evidence for a warmer and wetter climate very early in planetary history. The valley systems in some instances debouch into closed depressions that could have acted as local ponding basins for the flow. A survey of the Martian equatorial region shows that numerous local depressions at the confluence of valley systems exist. These depressions (approximately 100 km) typically are characterized by many valleys flowing into them and few or none flowing out. If ponding did take place, these basin would have contained lakes for some period during Mars' early warmer epoch. Although the collection basins are numerous, location of ones that have not suffered significant subsequent geologic modification is difficult. Some morphologic features suggest that volcanic lavas may have filled them subsequent to any early fluvial activity. Two detailed maps of valley systems and local ponding basins in USGC 1:2,000,000 subquadrangles were completed and a third is in progress. The completed regions are in Mare Tyrrhenum (MC-22 SW) and Margarifter Sinus (MC-19 SE), and the region in progress is in Iapygia (MC-21 NW). On the maps, the valley systems and interpreted margins of ponding basins are indicated. The depressions are of interest for two reasons. First, the depressions were surely the sites in which the materials eroded from the valleys were deposited. Such sediments could preserve important information about the physical conditions at the time of deposition. Second, the sediments could preserve evidence of water-atmosphere interactions during the early period of the Martian climate. Atmospheric carbon dioxide would dissolve in water, and solid carbonate minerals would tend to precipitate out to form carbonate sedimentary deposits. Formation of carbonates in this manner might account for some of the CO2 lost from the early more dense atmosphere.

  5. Active tectonics and Holocene versus modern catchment erosion rates at 300 MW Baspa II hydroelectric power plant (NW Himalaya, India)

    NASA Astrophysics Data System (ADS)

    Draganits, Erich; Grasemann, Bernhard; Gier, Susanne; Hofmann, Christa-Charlotte; Janda, Christoph; Bookhagen, Bodo; Preh, Alexander

    2015-04-01

    The Baspa River is one of the most important tributaries to the Sutlej River in the NW Himalaya (India). Its catchment is 1116 km2 in size, ranges from c. 6400 m asl to 1770 m asl and contains India's largest private hydroelectric facility, the 300 MW Baspa II. Geologically, the hydroelectric installation is located in the Higher Himalayan Crystalline, just above the active Karcham Normal Fault, which is reactivating the Early Miocene Main Central Thrust, one of the principal Himalayan faults. The area is seismically active and mass-movements are common. Around 8200 yrs BP the Baspa was dammed by a rock-avalanche dam, leading to the formation of the originally c. 260 m deep palaeo-lake Sangla palaeo-lake. Detailed sedimentological investigations and radiocarbon dating indicate that the palaeo-lake was completely filled with sediments until c. 5100 yrs BP. This makes the Sangla palaeo-lake to a very rare example of a mass-movement dam with very long duration and its lacustrine sediments represent a valuable archive for geological processes and environmental proxies within the Baspa catchment during the c. 3100 years of its existence - which are the aim of our study. At least 5 levels of soft-sediment deformation have been recorded in the exposed part of the lacustrine sediments of Sangla palaeo-lake, including brecciated laminae, overturned laminae, folds, faults and deformation bands, separated by undeformed deposits. They are interpreted as seismites, indicating at least 5 earthquakes within 2500 years strong enough to cause liquefaction. The 300 MW Baspa II hydro-electric power plant has been built exactly on top of this palaeo-lake. This special location represents a very rare possibility to evaluate the short-term, river load and hydrological parameters measured during the planning and operational stages of Baspa II with the long-term parameters gained from the palaeo-lake sediments from the catchment. This data show that the Mid-Holocene erosion rates of the

  6. Great Lakes

    USGS Publications Warehouse

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The wild plants and animals and the natural systems that support them in the Great Lakes region are valuable resources of considerable local, regional, and national interest. They are also, in part, transboundary resources that the U.S. shares with its Canadian neighbors to the north. The way these resources are changing over time is inadequately known and is a concern for resource users and for those charged with managing and protecting these unique and valuable resources. This chapter describes the wild plants and animals and the systems that support them in the Great Lakes region; addresses their condition; and points out the gaps in our knowledge about them that, if filled, would aid in their conservation and appropriate use.

  7. Quo vadis NW Black Sea benthic ecosystems?

    NASA Astrophysics Data System (ADS)

    Traian Gomoiu, Marian

    2016-04-01

    / thalasoterapy. Black Sea ecosystem restoration - Certainties and Uncertainties: Pressure on the Danube and other rivers has decreased, chemical discharges have decreased obviously, and yet there appear phenomena of water flowering - "red waters", hypoxia is still present at times and there is mass mortality of fish and other benthic organisms. Why? Signs of recovery should be considered cautiously and uncertainties may be resolved only in a longer time by increasing our scientific efforts. The results of the EU FP7 Project PERSEUS led to the identification of three important issues that should be resolved in order to achieve good environmental status: • Applying an adaptive management to increase the resilience of the ecosystems and to diminish the vulnerability of biodiversity; • Necessity of participative approach by stakeholders; • Identifying and obtaining adequate financial support for new R-D-I projects. Who are the actors in addressing and implementing the actions? • Academic educational and research institutions for adequate working condition; • More specialists trained for taxonomic groups; • Reasonable diversity of coordinating specialists, capable team leaders / satisfactory work packages; • Attracting NGO members towards nature conservation issues; • Resonable stakeholders committed to environmental issues. Studying the results of researches carried out by GeoEcoMar on the Romanian Black Sea coast in recent years, the author concluded that the major problems hampering progress towards a good ecosystem in NW Bent Black Sea are: • lack of diversity in the fields of research, both in theoretical and applied realms; • structural and functional consequences of ecological pressures and the disordered state of the ecosystems in the periods of paroxysmal eutrophication / pollution at the end of the 20th Century; • scarcity of data and knowledge on the Social-Economic System; • high costs of the new marine technology used directly in the sea and

  8. Groundwater hydrochemistry evolution in cyclone driven hydrological regimes, NW Australia

    NASA Astrophysics Data System (ADS)

    Skrzypek, G.; Dogramaci, S.; Grierson, P.

    2013-12-01

    Groundwater reserves supply the water needs of many arid regions around the world. Aquifer recharge in these regions is primarily depended on the amount and distribution of rainfall, coupled with exceedingly high rates of evaporation and interactions with both local and regional geomorphology and geology. In semi-arid northwest Australia, the majority of rainfall is delivered by large but infrequent cyclonic events and relatively more frequent but low intensity frontal systems. Changes to rainfall patterns due to global climate change may impact hydrological regimes, recharge rates and groundwater hydrochemistry. These changes may significantly restrict freshwater resources in the future. Between 2008 and 2012, we analysed >400 groundwater, surface and rainwater samples for stable isotope composition (δ2H and δ18O) and major ion chemistry. We then developed conceptual geochemical models of groundwater evolution for the Hamersley Basin (>100,000 km2) and a salt inventory for the Fortescue Marsh (the largest wetland in NW Australia) [1,2]. Fresh groundwater from the alluvium (-8.02 × 0.83‰) and fractured aquifers (-8.22 × 0.70‰) were hydrochemically similar and characterised by a very narrow range of δ18O [1]. In contrast, δ18O of saline and brine groundwater (TDS >10 g L-1) varies in wide range from +2.5 to -7.2‰ [2]. Most of the fresh and brackish groundwater reflects modern recharge and is evaporated by <20% prior to recharge. In contrast, highly saline and brine groundwater reflects mixing between modern rainfall, brackish water and older deep groundwater. The Fortescue Marsh primarily acts as a terminal basin for surface water from the upper Fortescue River catchment [2]. The stable isotope composition of the deep brine groundwater under the Marsh suggests a complex evolution, which cannot be explained by evaporation under current climatic conditions. The observed salinity and δ18O values may result from progressive evaporation from highly saline

  9. View south up 27th Street rightofway NW (formerly Lyons Mill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View south up 27th Street right-of-way NW (formerly Lyons Mill Road) along western edge of Female Union Band Cemetery. Vegetation obscures the cemetery's terraces. - Mount Zion Cemetery/ Female Union Band Cemetery, Bounded by 27th Street right-of-way N.W. (formerly Lyons Mill Road), Q Street N.W., & Mill Road N.W., Washington, District of Columbia, DC

  10. MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MARINA & MAINE STREETS FACING NW. DARKER COLORED HOME ON SE CORNER. NYSTROM VILLAGE, LIKE ATCHISON VILLAGE (HAER CA-326-N), HOUSED WORKERS DURING WORLD WAR II - Rosie the Riveter National Historical Park, Nystrom Village, Marina & Maine Streets, Richmond, Contra Costa County, CA

  11. 21. (Credit JTL) View looking NW at south elevations of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. (Credit JTL) View looking NW at south elevations of boiler room, old high service pumping room (1887) and beginning of 1900 filter room addition; wash water tank (1926) in background. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  12. 1. Creosote plant site (NW side) as viewed with a ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Creosote plant site (NW side) as viewed with a telephoto lens from Winslow ferry terminal. Eagle Harbor is in foreground. Buildings include Machine Shop on left, Boiler Building with stack, and Engine Room Building at center. Office is at far right next to tree. - Pacific Creosoting Plant, 5350 Creosote Place, Northeast, Bremerton, Kitsap County, WA

  13. 42. View from top of Brooklyn Tower looking NW showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. View from top of Brooklyn Tower looking NW showing main cables and suspendors with lower Manhattan in the background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  14. 3. DETAIL VIEW OF ONE ARCH SPAN, LOOKING NW ALONG ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL VIEW OF ONE ARCH SPAN, LOOKING NW ALONG EAST BANK OF SUSQUEHANNA RIVER. NOTE FLOOD STAGE MARKINGS ON PIER, ALSO LONGITUDINAL CONSTRUCTION JOINT IN ARCH BARREL. - Philadelphia & Reading Railroad, Susquehanna River Bridge, Spanning Susquehanna River, North of I-83 Bridge, Harrisburg, Dauphin County, PA

  15. 70. View from Promenade looking NW towards Manhattan up one ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. View from Promenade looking NW towards Manhattan up one of the center main cables with Brooklyn Tower in background. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York County, NY

  16. 4. General view looking NW along Richmond Branch Reading RR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. General view looking NW along Richmond Branch Reading RR tracks, showing Building 16 on left, stack associated with Building 3 and Building 22 on right. Building on far right is not part of the Dobson Mills complex (camera side of Scotts Lane). - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  17. 17. Detail of base of 'Flying Ram' in NW corner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Detail of base of 'Flying Ram' in NW corner of foyer. Camera is looking SW. First doorway beyond fountain leads to basement and men's lounge seen in WA-197-44. Second doorway leads to storefront corner at Seventh Ave. and Olive Way. (Aug. 1991) - Fox Theater, Seventh Avenue & Olive Way, Seattle, King County, WA

  18. Evidence for volcanism in NW Ishtar Terra, Venus

    NASA Technical Reports Server (NTRS)

    Gaddis, L.; Greeley, Ronald

    1989-01-01

    Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas.

  19. Lake sediment response to land-use and climate change during the last 1000 years in the oligotrophic Lake Sanabria (northwest of Iberian Peninsula)

    NASA Astrophysics Data System (ADS)

    Luque, J. A.; Julià, R.

    2002-04-01

    High-resolution sequential analysis of the upper 380 mm of a sediment core from Lake Sanabria, an oligotrophic freshwater lake in the granitic zone of the NW Iberian Peninsula, shows four lacustrine sedimentary episodes, some of which have been interpreted as the Little Ice Age (LIA). Radiometric dating of the core (C-14 Accelerator Mass Spectrometry (AMS)) gives an age of 875 AD for the oldest sedimentary episode. Subsequent variations are attributed to human influence on the catchment of Lake Sanabria: agricultural activity of the San Martı´n de Castañeda monastery during the Middle Ages, the breached Vega de Tera dam in January 1959, or the designation of Lake Sanabria as a natural park in 1978.

  20. Longevity of Lake Superior lake trout

    USGS Publications Warehouse

    Schram, Stephen T.; Fabrizio, Mary C.

    1998-01-01

    The age structure of mature lake trout Salvelinus namaycush from the Wisconsin waters of Lake Superior increased following a population recovery that has taken place since the 1960s. As the population aged, it became apparent that scales were unreliable aging structures. Beginning in 1986, we examined both scale and sagittal otolith ages from tagged fish with a known period at liberty. We found large discrepancies in scale and sagittal otolith ages of mature fish, such that scale ages were biased low. We estimated lake trout living up to 42 years, which is greater than previously reported from Lake Superior. Investigators studying lake trout population dynamics in the Great Lakes should be aware that lake trout can live longer than previously thought.

  1. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change

    NASA Astrophysics Data System (ADS)

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-01

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake.

  2. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change.

    PubMed

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-01

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake. PMID:26805936

  3. Temporal Succession of Ancient Phytoplankton Community in Qinghai Lake and Implication for Paleo-environmental Change

    PubMed Central

    Li, Gaoyuan; Dong, Hailiang; Hou, Weiguo; Wang, Shang; Jiang, Hongchen; Yang, Jian; Wu, Geng

    2016-01-01

    Tibetan lake sediments in NW China are sensitive recorders of climate change. However, many important plankton members do not leave any microscopic features in sedimentary records. Here we used ancient DNA preserved in Qinghai Lake sediments to reconstruct the temporal succession of plankton communities in the past 18,500 years. Our results showed that seven classes and sixteen genera of phytoplankton in the lake underwent major temporal changes, in correlation with known climatic events. Trebouxiophyceae and Eustigmatophyceae were predominant during the cold periods, whereas Chlorophyceae, Phaeophyceae, Xanthophyceae, Bacillariophyceae, and Cyanophyceae were abundant during the warm periods. The inferred changes in temperature, nutrients, precipitation, and salinity, as driven by the Westerlies and summer Monsoon strength, likely contributed to these observed temporal changes. Based on these correlations, we propose the phytoplankton index as a proxy to reconstruct the stadial versus interstadial climate change history in Qinghai Lake. This taxon-specific index is free of terrestrial contamination, sensitive to short-term climatic oscillations, and continuous in recording all climatic events in the lake. The validity of this index and its applicability to other lakes is demonstrated by its good correlations with multiple climate records of Qinghai Lake and another lake on the Tibetan Plateau, Kusai Lake. PMID:26805936

  4. Lake Volta, Ghana

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of Lake Volta in Ghana was acquired March 31, 2002 by the Moderate Resolution Imaging Spectroradiometer (MODIS). Lake Volta is one of the world's largest artificially created lakes. Lake Volta is actually a reservoir formed from the damming of the Volta River, and extends 250 miles north of the Akosombo Dam. The lake covers an area of 8,482 square km. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  5. Evolutionary characteristics of lakes and palaeoclimatic undulation in the Qaidam Basin, China

    NASA Astrophysics Data System (ADS)

    Huang, Qi; Teh-Lung, Ku; Phillips, Fred M.

    1993-03-01

    The Qaidam Basin is a tectonically controlled depression at 2700 m altitude on the northern margin of the Tibet Plateau. A succession of Neogene clastic sediments indicates lake depocentre migration from NW to SE. Towards late Pliocene, evaporative conditions developed with formation of gypsum, halite, celestite, mirabilite and bloedite. Continued deformation through Pleistocene developed a series of NW-SE trending domes and troughs. This setting continued to exert a controlling influence on basin and brine evolution and the progressive development of sulfate to chloride brines as dry conditions intensified in late Pleistocene, at the end of which, extensive flat floors were formed in Dalangtan, Qarhan and other playas. The model, which was set up based on the synthetic analyses, divides the fluctuating palaeoclimate since 750ka, B. P. into 11 warm and humid stages and 10 dry and cold stages. The water of the lakes evaporated during the dry-cold periods and were freshened during the warm-humid periods.

  6. Gondwana to Pangea: a detrital zircons tale from NW Iberia

    NASA Astrophysics Data System (ADS)

    Pastor-Galán, Daniel; Gutiérrez-Alonso, Gabriel; Brendan Murphy, J.; Fernández-Suárez, Javier; Hofmann, Mandy; Linnemann, Ulf

    2013-04-01

    The Cantabrian Zone of NW Iberia preserves a voluminous, almost continuous, sedimentary sequence that ranges from Neoproterozoic to Early Permian in age. Its tectonic setting is controversial and recent hypotheses include (i) passive margin deposition along the northern margin of Gondwana or (ii) an active continental margin or (iii) a drifting ribbon continent. In this paper we present detrital zircon U-Pb laser ablation age data from 13 samples from the Cantabrian Zone sequence ranging from Early Silurian to Early Permian in depositional age, which, together with previously published detrital zircon ages from Ediacaran-Ordovician strata, allow a comprehensive analysis of changing provenance through time. Laser ablation U-Pb geochronological analysis of detrital zircons in thirteen samples of the Cantabrian Zone of the NW Iberian Variscan belt reveal that this portion of Iberia was part of the northern passive-margin of Gondwana from the Ordovician to Late Devonian, until the onset of collision between Gondwana and Laurentia. Zircon populations in these samples show important similarities with zircons found in coeval detrital rocks from central North Africa. Additionally, the populations found in NW Iberia are coherent with a Saharan source. We suggest that NW Iberia was situated from Ordovician to Late Devonian along the Gondwana northern passive margin close to the paleoposition of central North Africa and Saharan craton. Additionally, the Carboniferous-Permian samples studied record the provenance changes produced during the Variscan collision and basement exhumation, the Cantabrian orocline formation and the subsequent detachment of the lithospheric mantle. The provenance changes reflect major topographic variations due to the afore mentioned processes during Late Devonian to Early Permian times. Detrital zircon studies are a useful tool that can complement regional syntheses in deducing paleogeographic locations, the occurrence of major tectonic events such

  7. Acanthocorbis mongolica nov. spec.: description of the first freshwater loricate choanoflagellate (Acanthoecida) from a Mongolian lake.

    PubMed

    Paul, Markus

    2012-01-01

    A new acanthoecid choanoflagellate species, Acanthocorbis mongolica sp. nov. was found in preserved phytoplankton samples from the freshwater lake Bayan Nuur (Uvs Nuur Basin, NW Mongolia) in concentrations of up to 1.8×10(5)cellsL(-1). It is the first well-documented species of the mainly marine order Acanthoecida to be found in a freshwater lake. The lorica structures were studied with scanning electron microscopy. Key morphological features of the vase-shaped lorica are spine bases that are composed of multiple (2-4) parallel costal strips, and the existence of two transverse costae. The ecological implications of this find are discussed. PMID:21862298

  8. Lake Nasser and Toshka Lakes, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Nasser (center) and the Toshka Lakes (center left) glow emerald green and black in this MODIS true-color image acquired March 8, 2002. Located on and near the border of Egypt and Norther Sudan, these lakes are an oasis of water in between the Nubian (lower right) and Libyan Deserts (upper left). Also visible are the Red Sea (in the upper right) and the Nile River (running north from Lake Nasser). Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  9. Lake trout rehabilitation in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

    1995-01-01

    Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

  10. Lakes Ecosystem Services Online

    EPA Science Inventory

    Northeastern lakes provide valuable ecosystem services that benefit residents and visitors and are increasingly important for provisioning of recreational opportunities and amenities. Concurrently, however, population growth threatens lakes by, for instance, increasing nutrient ...

  11. Utah: Salt Lake Region

    Atmospheric Science Data Center

    2014-05-15

    article title:  Winter and Summer Views of the Salt Lake Region     View Larger Image Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the ...

  12. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Chicago, IL. Great Lakes National Program Office.

    This book contains lesson plans that provide an integrated approach to incorporating Great Lakes environmental issues into elementary subjects. The book is divided into three subject areas: (1) History, which includes the origins of the Great Lakes, Great Lakes people, and shipwrecks; (2) Social Studies, which covers government, acid rain as a…

  13. A Killer Lake

    ERIC Educational Resources Information Center

    Horvath, Thomas

    2005-01-01

    In 1986, Lake Nyos, a volcanic lake in Cameroon, released a huge amount of carbon dioxide gas, killing over 1,700 people in the surrounding area. This case study, developed for use in a limnology or aquatic biology course, explores that event, introducing students to concepts relating to lake formation, thermal stratification, and dissolved gases.…

  14. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

    The Tenth Great Lakes Regional Meeting of the American Chemical Society met to assess current Chemical Research activity in the Great Lakes Basin, and addressed to the various aspects of the theme, Chemistry of the Great Lakes. Research areas reviewed included watershed studies, atmospheric and aquatic studies, and sediment studies. (BT)

  15. Lake Layers: Stratification.

    ERIC Educational Resources Information Center

    Brothers, Chris; And Others

    This teacher guide and student workbook set contains two learning activities, designed for fifth through ninth grade students, that concentrate on lake stratification and water quality. In the activities students model the seasonal temperature changes that occur in temperate lakes and observe the resulting stratification of lake waters. Students…

  16. Comparison between mechanisms of CO2 degassing from El Chichon volcanic lake, México, and Specchio di Venere lake, Pantelleria, Italia.

    NASA Astrophysics Data System (ADS)

    Jácome Paz, M. P.; Taran, Y.; Inguaggiato, S.; Collard, N.; Vita, F.; Pecoraino, G.

    2014-12-01

    We present results of the CO2 diffuse emission from the surface of two volcanic lakes: El Chichón (EC) in Mexico and Specchio di Venere (SV) on Pantelleria Island, Italy. Both lakes are drainless, have similar sizes (~2x105 m2) and similar input-output dynamics. However, they are drastically different in water chemistry. The SV lake is alkaline (pH >9) and of a high near constant salinity, whereas EC lake is acidic (pH 2.3) and of a low variable salinity. In the vicinity of both lakes there are thermal grounds with steam vents and hot springs and a high CO2 soil flux. The SV lake has high alkalinity (~70 meq/L), whereas the EC lake is characterized by high concentration of dissolved CO2. CO2 flux measurements from the surface of both lakes were made with the "floating" accumulation chamber. During the flux measuring, gas samples were taken for carbon isotopic analysis. Soil flux measurements were also made in the crater of El Chichon volcano and on the area adjacent to the SV lake. The preliminary results of CO2 fluxes indicate EC lake has a high CO2 flux with a mean value of 3500 g m-2 d-1, with the highest values alignment across NW-SE and NE-SW faults and a high degassing by bubbling gases, especially near the strongest NE fumarolic field. While SV has a mean value of the CO2 flux ~ 10 g m-2 d-1 and limited bubbling on the lake surface. High CO2 flux was measured from the soil near the lake at the Mofeta place. A net mean diffusion flux (without bubbles) from EC lake is about 350 times higher than that from SV lake (3500 g m-2 d-1 vs 10 g m-2 d-1). SV has the total CO2 flux by diffusion of ~3 ton d-1 from an area of 0.3 km2 and the total flux of 0.44 ton d-1 by bubbling areas at SW and S zones. The EC lake has the total CO2 flux of 840 ton d-1 from an area of 0.24 km2. The total CO2 output from SV is nevertheless about two times higher taking into account the seepage from the lake (~ 8 kg s-1) of highly carbonated water.

  17. The Enigma of the Origin of Round, Deep, Rimed Lakes in the Russian Heartland-Was Lake Smerdyachie Formed During the Impact of an Extraterrestrial Body?

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Gusiakov, V. K.; Kiselev, A.; Amelin, I. I.; Breger, D. L.; McCafferty, P.

    2014-12-01

    The heartland of Russia has many enigmatic deep lakes. Shallow lakes have a more obvious origin, perhaps as kettle lakes, oxbow lakes or subsidence features. Deep lakes, particularly round lakes with partial or complete rims are more problematic. Traditionally, round or nearly round lakes with rims are candidates for Holocene age impact structures. The problem is that there are too many such lakes in the Russian heartland- a minimum of 15 deep, round lakes with diameters between 0.2 and 3 km. Even with a possibly increased impact rate during the Holocene, these deep lakes would represent the entire budget of Holocene impacts concentrated in one small region of the Earth. We examine here Lake Smerdyachie, a previously proposed impact lake. Smerdyachie is perfectly round with a raised rim. It has a diameter of about 350 meters and a maximum water depth of over 30 m. The basement at Smerdyachie is at~40 meters depth. It consists of Carboniferous age carbonate rock with fossils of brachiopods, crinoids and gastropods. The overlying material consists of unconsolidated, sand and silt-sized, quartz-rich sediments. We found clasts of brachiopod, crinoid and gastropod-bearing Carboniferous carbonate rock up to 32 cm in diameter on the SE rim of Smerdyachie. These clasts are present over about 1/3 of the total circumference of the lake. We also made panned concentrates of the sediment on the rim. To the NW, the concentrated sediment has a negative magnetic susceptibility (-0.07 to -0.03 cgs units), consistent with a higher concentration of pulverized limestone. To the SE, the sediment has a positive magnetic susceptibility (0.06 to 0.35 cgs units). The areas of positive magnetic susceptibility lie on the SE two-thirds of the rim of the lake. The highest susceptibility value is from the sample taken closest to the lake shoreline on the SE rim. This spatial distribution of susceptibility could mean that there is a higher concentration of iron rich material on the SE side of

  18. Potential for Great Thrust Earthquakes in NE Colombia & NW Venezuela

    NASA Astrophysics Data System (ADS)

    Bilham, R. G.; Mencin, D.

    2013-05-01

    Sixty-five percent of the ≈19 mm/yr eastward velocity of the Caribbean Plate north of Aruba and the Guajira peninsula relative to the South American plate is accommodated by dextral slip on the Bocono Fault system in NW Venezuela at 12±1 mm/yr, the remaining ~3 mm/yr of shear apparently distributed to the NW of the fault (Perez et al., 2011). The N40E strike of the Bocono fault system, however, requires that 10.6±1 mm/yr of convergence should accompany this partitioned dextral shear, but GPS measurements reveal that less than 25% of this convergence occurs across the Venezuelan Andes. The remaining 6-8 mm of convergence is presumably accommodated by incipient subduction between the Bocono fault and a trench 300 km NW of the northern coast of Colombia. Hence NW Venezuela and NE Colombia may occasionally host great earthquakes. Our current poor understanding of the geometry of the plate interface permits the plate to be locked 300 km down-dip and possibly 600 km along-strike, and if the plate slips in 10 m ruptures it could do so every 1200 years in a M~9 earthquake. No great earthquake has occurred since 1492, since when ~4 m of potential slip has developed, but should slip occur on just 10% of the hypothesized décollement (100x150 km) it could do so now in an Mw=8.2 earthquake. In that a potential Mw>8 earthquake poses a future seismic and tsunami threat to the Caribbean it is important to examine whether great earthquakes have occurred previously near the NW Venezuela coast. It is possible that creep accommodates the entire convergence signal, since there is no suggestion from microseismicity for an abrupt locked-to-sliding transition, as, for example, signifies its location in the Himalaya. An alternative measure of future potential seismic energy release is to identify the locus and rate of present-day strain contraction. To this end, Venezuelan, Colombian and US (CU and UNAVCO) investigators are installing an array of more than a dozen continuous operating

  19. 14. Stairs in far NW corner of the North Section, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Stairs in far NW corner of the North Section, as viewed from atop pier. This photo, along with phot WA-116-E-1, are the only photographs of the North Section of Drydock 3 that were approved by the U.S. Navy for inclusion in this HAER report. The brick building in center distance is the Building 59, the Pattern Shop, which has been documented in the HAER report No. WA-116-A. - Puget Sound Naval Shipyard, Drydock No. 3, Farragut Avenue, Bremerton, Kitsap County, WA

  20. Food of lake trout in Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; Erkkila, Leo F.; Tetzloff, Clifford L.

    1965-01-01

    Stomachs were examined from 1,492 lake trout and 83 siscowets collected from Lake Superior. Data are given on the food of lake trout of legal size (17 inches or longer) by year, season, and depth of water, and on the relation between food and size among smaller lake trout. Fish contributed 96.7 to 99.9 per cent of the total volume of food in the annual samples. Ciscoes (Coregonus spp.) were most common (52.2 to 87.5 per cent of the volume) in 1950 to 1953 and American smelt ranked first (65.6 per cent of the volume) in 1963. Cottids were in 8.9 to 12.3 per cent of the stomachs in 1950 to 1953 but in only 4.3 per cent in 1963. Insects ranked second to fish in occurrence (9.6 per cent for the combined samples) and crustaceans followed at 3.9 per cent. The greatest seasonal changes in the food of lake trout were among fish caught at 35 fathoms and shallower. The occurrence of Coregonus increased from 34.6 per cent in February-March to 71.1 per cent in October-December. Smelt were in 76.9 per cent of the stomachs in February-March but in only 2.2 per cent in October-December. Cottids, Mysis relicta, and insects were most common in the July-September collections. Lake trout taken at depths greater than 35 fathoms had eaten a higher percentage of Cottidae and Coregonus than had those captured in shallower water. Smelt, ninespine sticklebacks, Mysis, and insects were more frequent in stomachs of lake trout from less than 35 fathoms. Crustaceans comprised more than 70 per cent of the total volume of food for 4.0- to 7.9-inch lake trout but their importance decreased as the lake trout grew larger. Pontoporeia affinis was the most common in the stomachs of 4.0- to 6.9-inch lake trout and Mysis held first rank at 7.0 to 12.9 inches. Ostracods were important only to 4.0- to 4.9-inch lake trout. As the lake trout became larger, the importance of fish grew from 4.4-per cent occurrence at 5.0 to 5.9 inches to 93.9 per cent at 16.0 to 16.9 inches. Smelt were most commonly eaten by

  1. The Lateglacial and Holocene history of annually laminated Lake Tiefer See

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Martin; Dräger, Nadine; Lampe, Reinhard; Lorenz, Sebastian; Kienel, Ulrike; Schult, Manuela; Słowiński, Michał; Wulf, Sabine; Zawiska, Izabela; Brauer, Achim

    2015-04-01

    Lake Tiefer See (N 53.59, E 12.53) is one of the rare lakes with a long sequence of annually laminated Holocene sediments in northern Central Europe. The lake is a valuable link between laminated lakes in more oceanic climates of the Eifel region and NW Germany and laminated lakes in the more continental climate of Poland. It thus provides great potential to study past climate, vegetation and human land use along that climate transition. The sediments of Lake Tiefer See show repeated changes in varve quality and composition. To disentangle in how far these changes relate to either past climate change, lake water level fluctuations or to changes in the local environment caused by e.g. human activity, we studied 16 sediment cores taken mainly from the lake margin. Almost all cores show interruptions in sedimentation namely during the mid-Holocene, suggesting that the lake water level has been lowered during this period. However, peat-gyttia alternations point at lake level fluctuations also during the early and late Holocene. Discontinuous sedimentation in cores from intermediate depth points at recurring slumping events. The pollen record additionally indicates prominent alternations in land use intensity throughout the late Holocene. By testing correlation between the hydrological changes, changes in land use intensity and changes in the sediment record we discuss effects of climate change and further factors on varve formation in Lake Tiefer See. 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.

  2. Stable isotope records of Late Quaternary climate and hydrology from Mediterranean lakes: the ISOMED synthesis

    NASA Astrophysics Data System (ADS)

    Roberts, N.; Jones, M. D.; Benkaddour, A.; Eastwood, W. J.; Filippi, M. L.; Frogley, M. R.; Lamb, H. F.; Leng, M. J.; Reed, J. M.; Stein, M.; Stevens, L.; Valero-Garcés, B.; Zanchetta, G.

    2008-12-01

    Lake isotope records can be used to assess the spatial coherency of Late Quaternary climate change across the circum-Mediterranean region. We place modern and palaeo-data within a simple conceptual lake response model to show that the isotope hydrology of most Mediterranean lakes has been influenced strongly by water balance, even in those systems that are chemically dilute (i.e. freshwater). δ18O data on biogenic and endogenic carbonates from 24 lake basins are used to reconstruct multi-millennial-scale trends since the LGM. While it is difficult to make direct comparisons between lake records in terms of single climatic parameters, coherent regional isotopic trends can be identified. During glacial times Mediterranean lakes deposited carbonates isotopically heavier in δ18O compared to the Holocene, partly due to source area effects. Isotopic enrichment was most marked during intervals corresponding to the H1 and Younger Dryas events, confirming that Late Pleistocene cold stages in the North Atlantic region were marked by aridity around much of the Mediterranean. Almost all Mediterranean lake records shifted to more depleted isotopic values during the Last Glacial-Interglacial Transition (LGIT). This shift is the reverse of the trend which characterised the same transition in lakes from northern and central Europe, and suggests that temperature changes were not an important direct driver of Mediterranean lake isotopic records over glacial-interglacial timescales. In the early Holocene, many lakes in the eastern part of the region were more depleted isotopically than in recent millennia. This corresponds with marine sapropel formation, both chronologically and geographically, and implies that increases in local rainfall contributed significantly to the creation of a freshwater lid and anoxia in the East Mediterranean Sea. In contrast, no such pattern is currently apparent from lake isotope records from the West Mediterranean, suggesting a possible NW-SE contrast

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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

  4. Water quality of Lake Austin and Town Lake, Austin, Texas

    SciTech Connect

    Andrews, F.L.; Wells, F.C.; Shelby, W.J.; McPherson, E.M.

    1988-01-01

    Lake Austin and Town Lake are impoundments on the Colorado River in Travis County, central Texas, and are a source of water for municipal industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Small vertical temperature variations in both lakes were attributed to shallow depths in the lakes and short retention times of water in the lakes during the summer months. The largest areal variations in dissolved oxygen generally occur in Lake Austin during the summer as a result of releases of water from below the thermocline in Lake Travis. Except for iron, manganese, and mercury, dissolved concentrations of trace elements in water collected from Lake Austin and Town Lake did not exceed the primary or secondary drinking water standards set by the US Environmental Protection Agency. Little or no effect of stormwater runoff on temperature, dissolved oxygen, or minor elements could be detected in either Lake Austin or Town Lake. Little seasonal or areal variation was noted in nitrogen concentrations in Lake Austin or Town lake. Total phosphorus concentrations generally were small in both lakes. Increased concentrations of nitrogen and phosphorus were detected after storm runoff inflow in Town Lake, but not in Lake Austin; densities of fecal-coliform bacteria increased in Lake Austin and Town Lake, but were substantially greater in Town Lake than in Lake Austin. 18 refs., 38 figs., 59 tabs.

  5. Brittle-fault deformation history in the NW Himalaya (Himachal Pradesh, India)

    NASA Astrophysics Data System (ADS)

    Hintersberger, E.; Decker, K.; Thiede, R.; Strecker, M.

    2009-04-01

    The Himalayan mountain belt and the Tibetan Plateau are the manifestations of intense crustal shortening and uplift along the southern margin of Eurasia associated with the India-Eurasia collision. While crustal shortening has been focused at lower elevations until the present day along the southern boundary of the Lesser Himalaya and the Siwalik ranges, several generations of both, orogen-parallel and orogen-perpendicular extensional structures have developed. These structures characterize the higher-elevation regions within the Higher and Tethyan Himalaya, suggesting syntectonic extension. In the NW Himalaya (India), extending from the deeply cut gorges of the Sutlej and Spiti rivers to the Garhwal Himalaya, closely spaced young normal faults, focal mechanisms of earthquakes with magnitudes between 5.2 and 6.8, and regional GPS measurements reveal ongoing E-W extension. Surprisingly, and in contrast to other extensional features observed in the Himalaya, this direction is neither parallel nor perpendicular to the NE-SW regional shortening direction. Here, we present new data obtained from structural geological mapping, fault kinematic analysis of hundreds of brittle faults, and remote sensing spanning the area between the Tso Morari Lake in the Tibetan Himalaya in the north and the mountain front in the Garhwal Himalaya in the south (30°-33°N/77°-79°E). In addition, we integrated published data on extensional phenomena in this region of the Himalaya. In the Garhwal Himalaya and the Sutlej-Spiti region, we collected and analyzed outcrop-scale brittle fault-planes with displacements of up to several cm. To analyze fault kinematic data (strike and dip of the fault, slip direction and sense of slip) for these micro-faults, we calculated strain axes for approx. 100 outcrop locations using the TectonicsFP program. This data set, as well as field observations on crosscutting relationships, mineralization of fault planes, and correlations with deformation structures

  6. Lake trout rehabilitation in Lake Huron

    USGS Publications Warehouse

    Eshenroder, Randy L.; Payne, N. Robert; Johnson, James E.; Bowen, Charles; Ebener, Mark P.

    1995-01-01

    Efforts to restore lake trout (Salvelinus namaycush) in Lake Huron after their collapse in the 1940s were underway in the early 1970s with completion of the first round of lampricide applications in tributary streams and the stocking of several genotypes. We assess results of rehabilitation and establish a historical basis for comparison by quantifying the catch of spawning lake trout from Michigan waters in 1929-1932. Sixty-eight percent of this catch occurred in northern waters (MH-1) and most of the rest (15%) was from remote reefs in the middle of the main basin. Sea lampreys (Petromyzon marinus) increased in the early 1980s in the main basin and depressed spawning populations of lake trout. This increase was especially severe in northern waters and appeared to be associated with untreated populations in the St. Marys River. Excessive commercial fishing stemming from unresolved treaty rights also contributed to loss of spawning fish in northern Michigan waters. Seneca-strain lake trout did not appear to be attacked by sea lampreys until they reached a size > 532 mm. At sizes > 632 mm, Seneca trout were 40-fold more abundant than the Marquette strain in matched-planting experiments. Natural reproduction past the fry stage has occurred in Thunder Bay and South Bay, but prospects for self-sustaining populations of lake trout in the main basin are poor because sea lampreys are too abundant, only one side of the basin is stocked, and stocking is deferred to allow commercial gillnetting in areas where most of the spawning occurred historically. Backcross lake trout, a lake trout x splake (s. Fontinalis x s. Namaycush) hybrid, did not reproduce in Georgian Bay, but this genotype is being replaced with pure-strain lake trout, whose early performance appears promising.

  7. Paleofloods and ancient fishing weirs in NW Iberian rivers

    NASA Astrophysics Data System (ADS)

    Viveen, Willem; Sanjurjo-Sanchez, Jorge; Goy-Diz, Ana; Veldkamp, Antonie; Schoorl, Jeroen M.

    2014-07-01

    A 15-m-thick, fluvial sedimentary record of the NW Iberian lower Miño River was studied. Grain-size analyses were performed and twelve samples were dated using optically stimulated luminescence dating techniques, documenting a 1300-yr-old reconstructed fluvial record that does not match with known climate fluctuations in the area, but is linked instead to the construction of a series of ancient fishing weirs (pesqueiras). The sedimentation phases are in agreement with known episodes of increased population density, which suggests active use of the pesqueiras. A number of sedimentation hiatuses in the fluvial record point towards damage to the pesqueiras during large-scale flooding in the Miño River basin, and a sudden drop in population probably due to the arrival of the plague in the 13th century AD. The oldest sedimentation phases started just after 700 AD, and we infer that the first pesqueiras were constructed around this time. This timing coincides with the transition of the NW Iberian landscape towards a more intensively used agricultural landscape, as evidenced from other geo-archeological investigations. The results demonstrate that the pesqueiras are several hundreds of years older than known from historical records, but not so old as to date back to the Roman occupation.

  8. Numerical modeling of Drangajökull Ice Cap, NW Iceland

    NASA Astrophysics Data System (ADS)

    Anderson, Leif S.; Jarosch, Alexander H.; Flowers, Gwenn E.; Aðalgeirsdóttir, Guðfinna; Magnússon, Eyjólfur; Pálsson, Finnur; Muñoz-Cobo Belart, Joaquín; Þorsteinsson, Þorsteinn; Jóhannesson, Tómas; Sigurðsson, Oddur; Harning, David; Miller, Gifford H.; Geirsdóttir, Áslaug

    2016-04-01

    Over the past century the Arctic has warmed twice as fast as the global average. This discrepancy is likely due to feedbacks inherent to the Arctic climate system. These Arctic climate feedbacks are currently poorly quantified, but are essential to future climate predictions based on global circulation modeling. Constraining the magnitude and timing of past Arctic climate changes allows us to test climate feedback parameterizations at different times with different boundary conditions. Because Holocene Arctic summer temperature changes have been largest in the North Atlantic (Kaufman et al., 2004) we focus on constraining the paleoclimate of Iceland. Glaciers are highly sensitive to changes in temperature and precipitation amount. This sensitivity allows for the estimation of paleoclimate using glacier models, modern glacier mass balance data, and past glacier extents. We apply our model to the Drangajökull ice cap (~150 sq. km) in NW Iceland. Our numerical model is resolved in two-dimensions, conserves mass, and applies the shallow-ice-approximation. The bed DEM used in the model runs was constructed from radio echo data surveyed in spring 2014. We constrain the modern surface mass balance of Drangajökull using: 1) ablation and accumulation stakes; 2) ice surface digital elevation models (DEMs) from satellite, airborne LiDAR, and aerial photographs; and 3) full-stokes model-derived vertical ice velocities. The modeled vertical ice velocities and ice surface DEMs are combined to estimate past surface mass balance. We constrain Holocene glacier geometries using moraines and trimlines (e.g., Brynjolfsson, etal, 2014), proglacial-lake cores, and radiocarbon-dated dead vegetation emerging from under the modern glacier. We present a sensitivity analysis of the model to changes in parameters and show the effect of step changes of temperature and precipitation on glacier extent. Our results are placed in context with local lacustrine and marine climate proxies as well

  9. Ocean - ice sheet interaction along the NW European margin during the last glacial phases

    NASA Astrophysics Data System (ADS)

    Becker, L. W. M.; Sejrup, H. P.; Haflidason, H.; Hjelstuen, B. O. B.

    2015-12-01

    The NW European continental margin was repeatedly covered by shelf edge glaciations during the last glacial cycles. Here, we present a compilation of new and previously published data from a SW to NE transect of 8 sediment cores raised along the upper continental slope. This study aims to investigate the interaction between sea surface conditions and the variability seen in the British Irish Ice Sheet (BIIS) and the Fennoscandian Ice Sheet (FIS) during the last 13-40 ka BP. Ice Rafted Debris (IRD) counts, IRD flux data, grain size data, the content of the polar planktonic foraminifera Neogloboquadrina pachyderma (sin) and ∂18O measurements were compiled and combined with new Bayesian age models. From 40-24.5 ka BP the build up and consecutive confluence of the BIIS and the FIS are reflected in sediment composition and flux data. Pulses of large quantities of fine material to the southern part of the transect suggest riverine BIIS related influx. The sediment composition in cores close to the Norwegian channel indicates that the Norwegian Channel Ice Stream (NCIS) was only active between 24.5-18.5 ka BP during the last glacial stage. The planktonic foraminifera data during this period strongly suggests a dependence of NCIS extent variability and pulses in warm Atlantic water entering the Nordic Seas. In the northernmost cores rapidly deposited, laminated sediments and ∂18O spikes in planktonic foraminifera dated to 18.5 ka BP were interpreted as meltwater plume deposits. This may reflect NCIS retreat allowing BIIS and FIS to unzip and route ice dammed lake- and meltwater to the margin. In conclusion, the investigation suggests a close co-variation in extent of marine based parts of the BIIS, the FIS and ocean circulation while demonstrating the strong influence of the local glacial history on standard open marine proxies. This suggests that tuning chronologies of single marine records to ice cores in some regions might be more challenging than previously

  10. Evolution and erosional dynamics of intermontane basins on the Puna Plateau, NW Argentina

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Strecker, M. R.

    2014-12-01

    The Puna Plateau in NW Argentina is the southern part of the second-largest orogenic plateau on Earth with a mean elevation of 4.0 ± 0.5 km (±2s). The Puna is an integral part of the south-central Andes that exhibit a steep E-W topographic and climatic gradient: The first windward topographic rise east of the Puna constitutes a significant orographic barrier resulting in high orographic rainfall. Westward, the higher-elevation areas of the windward flanks become progressively drier, until arid conditions are attained in the orogen interior. The Puna repeatedly experienced significant paleoclimatic changes reflected by fluvial and lacustrine terraces associated with lake highstands related to deeper penetration of moisture into the orogen and thus an orogenward shift of the climate gradient. The southern Puna is compartmentalized into more than 500 separate, internally-drained sedimentary basins with varying catchment size. Here, we quantify the erosion-rate gradients and their impact on basin evolution and their importance on the formation of the plateau morphology. We rely on sedimentary archives, digital topography, and a new set of cosmogenic inventories of river sands (10Be) and bedrock-erosion rates (10Be and 26Al) from the eastern and central plateau. Erosion rates from internally drained catchments in the eastern plateau are similar to the externally drained, semi-arid intermontane basins in the E Cordillera, which bounds the plateau, but are ten-fold (or more) lower than erosion rates in the humid and steep sections along the eastern windward flanks. Within the plateau realm, erosion rates are ten-fold lower in the central than in the eastern parts. We analyze high-resolution topography from ASTER- and interferometry-derived Digital Elevation Models (DEMs) that we have validated with more 10'000 differential GPS ground control points. We demonstrate distinct topometric gradients across the Puna that can be linked to spatial variations in rainfall and

  11. Backscatter from ice growing on shallow tundra lakes near Barrow, Alaska, winter 1991-1992

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Wakabayashi, H.; Weeks, W. F.; Morris, K.

    1993-01-01

    The timing of freeze-up and break-up of Arctic lake ice is a potentially useful environmental indicator that could be monitored using SAR. In order to do this, it is important to understand how the properties and structure of the ice during its growth and decay affect radar backscatter and thus lake ice SAR signatures. The availability of radiometrically and geometrically calibrated digital SAR data time series from the Alaska SAR Facility has made it possible for the first time to quantify lake ice backscatter intensity (sigma(sup o)) variations. This has been done for ice growing on shallow tundra lakes near Barrow, NW Alaska, from initial growth in September 1991 until thawing and decay in June 1992. Field and laboratory observations and measurements of the lake ice were made in late April 1992. The field investigations of the coastal lakes near Barrow confirmed previous findings that, (1) ice frozen to the lake bottom had a dark signature in SAR images, indicating weak backscatter, while, (2) ice that was floating had a bright signature, indicating strong backscatter. At all sites, regardless of whether the ice was grounded or floating, there was a layer of clear, inclusion-free ice overlaying a layer of ice with dense concentrations of vertically oriented tubular bubbles. At some sites, there was a third layer of porous, snow-ice overlaying the clear ice.

  12. Stage fluctuations of Wisconsin lakes

    USGS Publications Warehouse

    House, Leo B.

    1985-01-01

    This report describes lake-stage fluctuations of 83 gaged lakes in Wisconsin and presents techniques for estimating stage fluctuation at ungaged lakes. Included are stage information at 83 lakes and stage-frequency data for 32 of these lakes that had sufficient record for analysis. Lakes are classified by a hydrologic-topographic lake classification scheme as ground-water flowthrough (GWF) lakes, surface-water drainage (SWD) lakes, and surface-water flow-through (SWF) lakes. Lakes within the same class were found to have similar water-level fluctuations. The lake-stage records indicate that most annual maximums occur during the months of May and June for all three classes. Annual minimum lake levels generally occur in September for surface-water drainage lakes, in March for surface-water flowthrough lakes, and in November for ground-water flow-through lakes. Data for each lake include location, period of water-level record, hydrologic classification, drainage area, surface area, lake volume, maximum depth, long-term mean stage and its standard deviation, maximum and minimum observed lake stage, and the average annual lake-stage fluctuation.

  13. Draft genome sequences of two Campylobacter jejuni clinical isolates, NW and D2600.

    PubMed

    Jerome, John P; Klahn, Brian D; Bell, Julia A; Barrick, Jeffrey E; Brown, C Titus; Mansfield, Linda S

    2012-10-01

    The Campylobacter jejuni human clinical isolates NW and D2600 colonized C57BL/6 interleukin-10-deficient (IL-10(-/-)) mice without inducing a robust inflammatory response (J. A. Bell et al., BMC Microbiol. 9:57, 2009). We announce draft genome sequences of NW and D2600 to facilitate comparisons with strains that induce gastrointestinal inflammation in this mouse model.

  14. Hydrology of Indiana lakes

    USGS Publications Warehouse

    Perrey, Joseph Irving; Corbett, Don Melvin

    1956-01-01

    The stabilization of lake levels often requires the construction of outlet control structures. A detailed study of past lake-level elevations and other hydologic date is necessary to establish a level that can be maintained and to determine the means necessary for maintaining the established level. Detailed lake-level records for 28 lakes are included in the report, and records for over 100 other lakes data are available in the U.S. Geological Survey Office, Indianapolis, Ind. Evaporation data from the four Class A evaporation station of the U. S. Weather Bureau have been compiled in this report. A table showing the established legal lake level and related data is included.

  15. Origins of rainbow smelt in Lake Ontario

    USGS Publications Warehouse

    Bergstedt, Roger A.

    1983-01-01

    The first rainbow smelt (Osmerus mordax) to enter Lake Ontario were probably migrants from an anadromous strain introduced into New York's Finger Lakes. Since the upper Great Lakes were originally stocked with a landlocked strain from Green Lake, Maine, subsequent migration to Lake Ontario from Lake Erie makes Lake Ontario unique among the Great Lakes in probably having received introductions from two distinct populations.

  16. David Morrison on Lake Vostok

    NASA Video Gallery

    Dr. David Morrison discusses the implications of research possibilities at Lake Vostok, one of the largest subglacial lakes located over two miles beneath the ice in Antarctica. The lake has been c...

  17. Great Lakes Literacy Principles

    NASA Astrophysics Data System (ADS)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

    Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

  18. Transition In Style Of Miocene Volcanism And Inception And Style Of Faulting In The NW Basin And Range Province, Southern Oregon

    NASA Astrophysics Data System (ADS)

    Scarberry, K.; Grunder, A.; Meigs, A.

    2007-12-01

    New data from the northwest Basin and Range province in SE Oregon indicate a shift from arc-related volcanism to extension-related volcanism from the Early Miocene to the Late Miocene, respectively. New 40Ar-39Ar ages of Miocene volcanic rocks indicate two episodes of volcanism, between ~21-23 Ma and again at ~9-7 Ma. These episodes occurred prior to and during development of NW- and NNE-striking extensional faults near Abert Rim, one of the primary Basin and Range faults in southern Oregon. The Early Miocene Coleman Hills, located within the hanging wall of Abert Rim, are built of successively erupted rhyolite domes (21.79 ± 0.66 Ma, 2 σ), dacite domes (21.70 ± 0.56 Ma) and a central basaltic andesite to andesite volcano (22.02 ± 0.54 Ma). The Rabbit Hills occur in the footwall of Abert Rim and yield ages of 22.33 ± 0.24 Ma and 20.34 ± 0.36 Ma for rhyolite and 23.12 ± 0.48 Ma for basaltic andesite. Abundant dikes within Early Miocene volcanoes mimic the strike of both the NW and NNE, Late Miocene faults, yet it is not obvious that extensional faulting was active during this time. Middle Miocene volcanic activity is represented by 150-m thick section of Steens Basalt that covered ~500 m of volcanic paleotopography at the Coleman Hills. The age of the basalt (16.12 ± 0.30 Ma) and its composition indicate that it correlates to the upper part of the section in the source region at Steens Mountain, ~100 km to the east. Late Miocene volcanism near Lake Abert is bimodal. Silicic centers include: 8.79 ± 0.30 Ma Flint Ridge (dacite) and 8.58 ± 0.16 Ma Juniper Mountain (rhyolite). Mafic lavas include: 8.69 ± 0.42 Ma (basaltic andesite) and 7.71 ± 0.42 Ma (high-alumina olivine tholeiite). Chemical correlation places their source at Venator Butte, a small shield volcano. Geochemical data support attributing the Early Miocene magmatism to arc volcanism of the ancestral Cascades. The Late Miocene volcanism is intimately tied to the structural development of the NNE

  19. 51. (Credit JTL) Interior view (looking NW) of new pumping ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. (Credit JTL) Interior view (looking NW) of new pumping room built in 1921. In the right foreground is #1 low service pump built in 1897. Installed at McNeil in 1898, it was not moved during the building of this room in 1921. Beyond is a 5 mgd capacity Worthington-Snow cross-compound, duplex crank-and-fly-wheel engine built in 1920. Behind the worthington is an 8 mgd Allis-Chalmers engine of the same configuration. it was built in 1911, but not installed at McNeil until 1927. Both engines have condensers. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  20. Climate or vegetation change - what drove Holocene lake level fluctuations in NE-Germany?

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Martin; Blume, Theresa; Dreibrodt, Janek; Heidbüchel, Ingo

    2016-04-01

    Lake Tiefer See (N 53.59, E 12.53) is one of the rare lakes with a long sequence of annually laminated Holocene sediments in northern Germany. The lake is a valuable link between laminated lakes in more oceanic climates of the Eifel region and NW Germany and laminated lakes in the more continental climate of Poland. The lake provides great potential to study past climate, vegetation and human land use along that climate transition; it is thus a core study site of the ICLEA virtual institute. One prominent feature of Lake Tiefer See are pronounced lake level fluctuations during the Holocene. Such changes are often interpreted in terms of climatic fluctuations. However, climate fluctuations are supposed to be small during the Holocene. Groundwater formation and thus lake levels may on the other hand be strongly influenced by the plant cover. We therefore hypothesize that the lake level fluctuations have largely been driven by vegetation change in the catchment area. To validate this hypothesis, we test whether the magnitude and timing of the lake level changes corresponds to vegetation change in the catchment area. Analysis is based on quantitative vegetation analysis that includes both the REVEALS model and the extended downscaling approach (EDA). REVEALS translates pollen deposition from large lakes such as Tiefer See into regional vegetation cover. This method produces a continuous record of vegetation change, yet it is unable to reconstruct vegetation patterns in the catchment area. We therefore for specific time slices additionally apply the EDA to explore these patterns. Both methods are now available in the R package DISQOVER. Vegetation cover and estimates of climate variables are then used to estimate cumulative transpiration and ultimately groundwater recharge. Differences in groundwater recharge are likely to cause fluctuations in groundwater levels and thus also lake levels, as this lake is largely groundwater fed. While only rough estimates, these

  1. Late-Glacial to early Holocene basin development of annually laminated Lake Tiefer See

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Martin; Lorenz, Sebastian; Schult, Manuela; Lampe, Reinhard; Dräger, Nadine; Wulf, Sabine; Brauer, Achim

    2014-05-01

    Lake Tiefer See (N 53.59°, E 12.53°) is one of the rare lakes with a long sequence of annually laminated Holocene sediments in northern Central Europe. The lake is thus of great potential for past climate, vegetation and human land use studies. It furthermore provides a valuable link between laminated lakes in more oceanic climates of the Eifel region and NW Germany and laminated lakes in the more continental climate of Poland. The sediments of Lake Tiefer See are not uniform but show repeated changes in varve composition and include several non-varved sequences. Interpreting these changes requires a sound understanding of the deposition processes in the lake and the development of the lake basin itself. While modern sediment deposition is studied in an extensive monitoring program, we explore lake basin development using numerous cores from the lake margins down to the bottom of the lake. The lake is exceptionally deep (62 m) with steep slopes and may thus be susceptible to sediment re-deposition and focusing. Most marginal cores, which reach down to 10 m water depth, show a prominent basal peat layer. This peat layer indicates that basin development started by paludification of an originally flat surface following dead-ice melting. However, even in neighboring cores the timing of the onset of peat formation appears to differ substantially. While in some cores, the prominent Laacher See Tephra (12.880 cal. BP) is found at the bottom of the peat layer, it is found well above the peat basis in other cores. Dead-ice melting may thus initially have produced a pattern of shallow depressions with ongoing peat formation within a still terrestrial surface. The formation of the deep lake is than indicated by an abrupt shift to calcareous gyttjas, which show an initially increased silicate content. The lake obviously only developed long after first peat deposition, possibly in the early Holocene. Further dates to verify this hypothesis are expected. In several marginal

  2. Atypical coastal environmental change during Copper Age - Bronze Age transition (Rio de Moinhos, NW Portugal) - preliminary results

    NASA Astrophysics Data System (ADS)

    Granja, Helena; Danielsen, Randi

    2015-04-01

    The research is part of an ongoing project of geo-archaeology from Rio de Moinhos beach (Esposende, NW Portugal), where an extensive area of dark sedimentary outcrops and a large amount of ceramic remains from a Roman shipwreck are present. The dark sedimentary deposit, presenting tree stumps and roots in life position, partially covers a rocky platform that extends seawards. Over the platform, that presents many pits of sea urchins (infralittoral environment) as well as salt pans (supratidal environment), a marine rusty conglomerate is present in some places. Several hand gauge cores were extracted in the sedimentary deposit whose maximum depth do not exceed 50cm. Samples from cores and outcrops were analysed for grain size, mineralogical composition, pollen and diatom content and radiocarbon dated. This work concerns sediment size analysis, dating and pollen. Tree stumps and roots of Alnus glutinosa dated 6310-6220 cal BP are in the base of the sedimentary sequence that presents a gradual passage from very fine sands to clayey silts, all of them organic and very poorly sorted. Pollen analysis revealed an initial wetland habitat containing Alnus, inundated ca 5645-5585 cal BP due to rising sea level at the time. A brackish lagoon formed at the site presumably protected by a clastic barrier seaward. Similar formations of lagoons are detected all along the Portuguese coast, typically disappearing with time due to sand infilling. In this case, however, the brackish lagoon turned into a fresh water lake ca 4485-4440 cal BP. This may have been a natural development caused by permanent closing of the clastic barrier but human interference cannot be excluded as anthropic activity was detected since formation of the lagoon. The lake seems to have filled in with sand at some point in time subsequent to ca 3750-3725 cal BP, the date of the top lake sediment. However, shipwreck vestiges from the Roman Period presently dispersed over the lake sediment, suggests a later date

  3. Lakes, Lagerstaetten, and Evolution

    NASA Astrophysics Data System (ADS)

    Kordesch, E. G.; Park, L. E.

    2001-12-01

    The diversity of terrestrial systems is estimated to be greater than in the marine realm. However no hard data yet exists to substantiate this claim. Ancient lacustrine deposits may preserve an exceptionally diverse fossil fauna and aid in determining continental faunal diversities. Fossils preserved in lake deposits, especially those with exceptional preservation (i.e. Konservat Lagerstaetten), may represent a dependable method for determining species diversity changes in the terrestrial environment because of their faunal completeness. Important Konservat Lagerstaetten, such as the Green River Formation (US) and Messel (Germany), both Eocene in age, are found in lake sediments and show a remarkable faunal diversity for both vertebrates and invertebrates. To date information from nearly 25 lake lagerstaetten derived from different types of lake basins from the Carboniferous to the Miocene have been collected and described. Carboniferous sites derive from the cyclothems of Midcontinent of the US while many Cenozoic sites have been described from North and South America as well as Europe and Australia. Asian sites contain fossils from the Mesozoic and Cenozoic. With this data, insight into the evolutionary processes associated with lake systems can be examined. Do lakes act as unique evolutionary crucibles in contrast to marine systems? The speciation of cichlid fishes in present-day African lakes appears to be very high and is attributed to the diversity of environments found in large rift lakes. Is this true of all ancient lakes or just large rift lakes? The longevity of a lake system may be an important factor in allowing speciation and evolutionary processes to occur; marine systems are limited only in the existence of environments as controlled by tectonics and sea level changes, on the order of tens of millions of years. Rift lakes are normally the longest lived in the millions of years. Perhaps there are only certain types of lakes in which speciation of

  4. Lake level and climate records of the last 90 ka from the Northern Basin of Lake Van, eastern Turkey

    NASA Astrophysics Data System (ADS)

    Çağatay, M. N.; Öğretmen, N.; Damcı, E.; Stockhecke, M.; Sancar, Ü.; Eriş, K. K.; Özeren, S.

    2014-11-01

    Sedimentary, geochemical and mineralogical analyses of the ICDP cores recovered from the Northern Basin (NB) of Lake Van provide evidence of lake level and climatic changes related to orbital and North Atlantic climate system over the last 90 ka. High lake levels are generally observed during the interglacial and interstadial periods, which are marked by deposition of varved sediments with high total organic carbon (TOC), total inorganic carbon (TIC), low detrital influx (high Ca/F) and high δ18O and δ13C values of authigenic carbonate. During the glacial and stadial periods of 71-58 ka BP (Marine Isotope Stage 4, MIS4) and end of last glaciation-deglaciation (30-14.5 ka BP; MIS3) relatively low lake levels prevailed, and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates. Millennial-scale variability of the proxies during 60-30 ka BP (MIS3 is correlated with the Dansgaard-Oeschger (D-O)) and Holocene abrupt climate events in the Atlantic. These events are characterized by laminated sediments, with high TOC, TIC, Ca/Fe, δ18O and δ13C values. The Lake Van NB records correlate well in the region with the climate records from the lakes Zeribar and Urmia in Iran and the Sofular Cave in NW Anatolia, but are in general in anti-phase to those from the Dead Sea Basin (Lake Lisan) in the Levant. The relatively higher δ18O values (0 to -0.4‰) for the interglacial and interstadial periods in the Lake Van NB section are due to the higher temperature and seasonality of precipitation and higher evaporation, whereas the lower values (-0.8 to -2‰) during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation. The high δ18O values (up to 4.2‰) during the Younger Dryas, together with the presence of dolomite and low TOC contents, supports evaporative conditions and low lake level. A gradual decrease in the δ18O values from an

  5. Assessing the potential environmental impact of Athabasca oil sands development in lakes across Northwest Saskatchewan

    NASA Astrophysics Data System (ADS)

    Ahad, J. M.; Cumming, B. F.; Das, B.; Sanei, H.

    2011-12-01

    The continued development of Canada's Athabasca oil sands poses a significant environmental challenge. Low buffered boreal lakes located downwind of the prevailing eastward wind direction may be threatened by acidification and elevated inputs of airborne contaminants such as polycyclic aromatic hydrocarbons (PAHs). An accurate assessment of the impact that increased levels of bitumen production may have on lakes in the region requires an understanding of the historic variability within these systems prior to at least the past several decades. Here we report concentrations of PAHs, δ13C and δ15N of organic matter (OM), Rock-Eval pyrolysis analyses, and distributions of n-alkanes in dated sediment cores from ten lakes located across NW Saskatchewan. Concentrations of PAHs were relatively low (< 100 ng/g for Σ 16 EPA Priority PAHs at each lake) and in general showed no substantial increases over the past 30 years. Retene, which is often associated with the combustion of coniferous wood, was generally the most abundant PAH amongst those reported, demonstrating the importance of forest fires as a principal PAH source. Plots of Hydrogen Index (HI) versus Oxygen Index (OI) fell within a relatively narrow range typical for sediments containing a high content of algal-derived OM. Relatively lower C/N ratios and higher abundances of C17 n-alkane in more recent sediments pointed to an increasingly larger component of algal-derived OM. In all ten lakes δ13C showed gradual upcore depletions that fell within the expected range for fossil fuel combustion (i.e., Suess effect), although this alone may not explain the up to ~3% depletion observed in several of the lakes. In conjunction with the other upcore trends these data may suggest a possible increase in primary productivity over the past several decades in many of the lakes studied. δ15N signatures were more variable, showing upcore increases in some lakes and upcore depletions in others. The increasingly lighter values

  6. An investigation of the origin of Rock City and cause of piping problems at Mountain Lake, Giles County, Virginia

    NASA Astrophysics Data System (ADS)

    Atallah, Nidal Walid

    Mountain Lake is one of only two natural lakes in the state of Virginia. The lake's origin has been attributed to either a natural solution-collapse basin, or to a landslide damming the valley of northwesterly flowing Pond Drain, or to a NW-SE trending fracture lineation. The lake is located within the breached northwest limb of a gently plunging anticline, a part of the larger Valley and Ridge physiographic province. In recent years, the lake drained almost completely, exposing the lake bottom and revealing the presence of four sinkhole-like depressions, containing piping holes at their sides and bottoms, at the northeastern and northwestern margins of the lake. This study focuses on the most likely origin of large sandstone blocks present at the northern end of the lake in an area locally referred to as "Rock City", including mapping of the block locations and analyzing the mode and extent of displacement that they have undergone. An additional objective is to investigate the piping potential of the lake-bottom sediment and its role in seepage out of the lake basin causing lake-level fluctuations. Mapping of Rock City was conducted by taking GPS readings at the corners of the rock blocks and using ArcMap Software. Investigations of the displacement mode of the rock blocks was done by comparing the measured orientations of principal discontinuity sets, forming the rock-block boundaries, with discontinuity orientations of undisturbed outcrops within the headscarp, using stereonet analysis. Grain size analysis, Atterberg limits, and a compaction-mold permeameter test were used to evaluate lake sediment's susceptibility to piping. Field observations and discontinuity data analysis indicate that Rock City is a landslide that dammed the valley of Pond Drain, consequently forming the lake. The primary mode of slope movement involves lateral spreading that is associated with extension occurring along discontinuities. The Tuscarora Sandstone rock blocks comprising Rock

  7. High-resolution palaeoecological and sedimentological records as a tool for understanding pre- and protohistoric settlement and land-use systems in Sandy Flanders (NW Belgium)

    NASA Astrophysics Data System (ADS)

    Court-Picon, Mona; Polfliet, Tim; Serbruyns, Lynn; de Smedt, Phillippe; Zwertvaegher, Ann; Bats, Machteld; de Reu, Jeroen; Werbrouck, Ilke; Verniers, Jacques; Crombe, Philippe

    2010-05-01

    The area of Sandy Flanders, situated between the North Sea coast and the lower course of the Scheldt River in NW Belgium, is a relatively flat and low-lying area situated at the southern limit of the lowland cover sand region of the NW European plain. During the Late Pleniglacial and the Late Glacial, numerous, generally small but elongated sand dunes, shallow lakes and wet depressions were formed. During the last three decades intense archaeological prospection has taken place in this region, which is now one of the most intensively surveyed areas of NW Europe. This has led to the production of archaeological distribution maps, which show a distinct pattern regarding the temporal and spatial distribution of these archaeological sites. Some areas with a presumed high ecological value, such as the large but shallow Late Glacial fossil lake of the Moevaart Depressie (ca. 15km long and 2,5km wide), seem to have been attractive settlement locations in Prehistory, given the high amount of close-lying sites along its borders and on the cover sand ridge on its northern border. Habitation however seems to have ‘moved' in time, and is completely absent in Protohistory and even the Roman Period. During the Late Glacial and Holocene the landscape in the Belgian area of Sandy Flanders was subjected to major changes due to climatic fluctuations, and besides human factors, environmental conditions such as topography, soil, vegetation, but also hydrology and climate, may have influenced settlement conditions throughout time and played a role in this change in site location and the occupational history of the region. In this light an inter-disciplinary project 'Prehistoric settlement and land-use systems in Sandy Flanders (NW Belgium): a diachronic and geoarchaeological approach' (GOA project, UGent), involving archaeology, geography, palaeoecology, sedimentology and geophysical survey, has been undertaken. The study of both "empty" and densely inhabited areas is ongoing and

  8. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

    Describes a study that included classroom lessons on hydroelectric power, the history and construction of a nearby lake, data recording, the use of field guides, and methods of counting natural populations. The study culminated in a field trip to the lake. (JRH)

  9. The Great Lakes.

    ERIC Educational Resources Information Center

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  10. Great Salt Lake, Utah

    USGS Publications Warehouse

    Stephens, Doyle W.; Gardner, Joe F.

    1999-01-01

    This document is intended as a source of general information and facts about Great Salt Lake, Utah. This U.S. Geological Survey information sheet answers frequently asked questions about Great Salt Lake. Topics include: History, salinity, brine shrimp, brine flies, migratory birds, and recreation. Great Salt Lake, the shrunken remnant of prehistoric Lake Bonneville, has no outlet. Dissolved salts accumulate in the lake by evaporation. Salinity south of the causeway has ranged from 6 percent to 27 percent over a period of 22 years (2 to 7 times saltier than the ocean). The high salinity supports a mineral industry that extracts about 2 million tons of salt from the lake each year. The aquatic ecosystem consists of more than 30 species of organisms. Harvest of its best-known species, the brine shrimp, annually supplies millions of pounds of food for the aquaculture industry worldwide. The lake is used extensively by millions of migratory and nesting birds and is a place of solitude for people. All this occurs in a lake that is located at the bottom of a 35,000-square-mile drainage basin that has a human population of more than 1.5 million.

  11. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

    ... backdrops for the 2002 Winter Olympics, to be held in Salt Lake City, Utah. The mountains surrounding Salt Lake City are renowned for ... western edge of the Rocky Mountains and eastern rim of the Great Basin. This early-winter image pair was acquired by the Multi-angle ...

  12. The lakes of Titan

    USGS Publications Warehouse

    Stofan, E.R.; Elachi, C.; Lunine, J.I.; Lorenz, R.D.; Stiles, B.; Mitchell, K.L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.

    2007-01-01

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70?? north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table. ??2007 Nature Publishing Group.

  13. Great Lakes: Great Gardening.

    ERIC Educational Resources Information Center

    New York Sea Grant Inst., Albany, NY.

    This folder contains 12 fact sheets designed to improve the quality of gardens near the Great Lakes. The titles are: (1) "Your Garden and the Great Lakes"; (2) "Organic Gardening"; (3) "Fruit and Vegetable Gardening"; (4) "Composting Yard Wastes"; (5) "Herbicides and Water Quality"; (6) "Watering"; (7) "Soil Erosion by Water"; (8) "Soil…

  14. Lake Wobegon Dice

    ERIC Educational Resources Information Center

    Moraleda, Jorge; Stork, David G.

    2012-01-01

    We introduce Lake Wobegon dice, where each die is "better than the set average." Specifically, these dice have the paradoxical property that on every roll, each die is more likely to roll greater than the set average on the roll, than less than this set average. We also show how to construct minimal optimal Lake Wobegon sets for all "n" [greater…

  15. Great Lakes Teacher's Guide.

    ERIC Educational Resources Information Center

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  16. Lake Superior revisited 1984

    USGS Publications Warehouse

    MacCallum, Wayne R.; Selgeby, James H.

    1987-01-01

    The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably at or near pre-sea lamprey abundance. Stocks of lake whitefish (Coregonus clupeaformis) appear to have fully recovered; commercial catches are at or above historical levels. Lake herring (Coregonus artedii) are recovering rapidly in U.S. waters and are abundant in western Canadian waters. The population of rainbow smelt (Osmerus mordax), which declined in the 1970s, is recovering. Pacific salmon (Oncorhynchus) are becoming more abundant as a result of increased stocking in U.S. waters and are reproducing in most suitable tributaries; they have become significant in anglers' creels.

  17. Lakes and reservoirs

    SciTech Connect

    Taub, F.B.

    1984-01-01

    This volume in the Ecosystems of the World series studies lakes and reservoirs. The book opens with a discussion of the ecosystem processes that are common to all lakes and reservoirs and then proceeds to a description of mathematical models of these processes. The chapters concentrate on lakes and reservoirs in different parts of the world, ranging from polar to tropical lakes, and in many of the chapters the effects of human activities such as dam construction, increased nutrient inputs, toxic contaminants and fish introduction, are also considered. The book concludes with a summary of the efforts at lake restoration that are being undertaken in many communities in an attempt to undo the damage that has resulted from some of these activities.

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

    USGS Publications Warehouse

    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.

    2014-01-01

    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.

  19. Spatial patterns in PCB concentrations of Lake Michigan lake trout

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.; Brown, Edward H.; Eck, Gary W.; Schmidt, Larry J.; Hesselberg, Robert J.; Chernyak, Sergei M.; Passino-Reader, Dora R.

    1999-01-01

    Most of the PCB body burden in lake trout (Salvelinus namaycush) of the Great Lakes is from their food. PCB concentrations were determined in lake trout from three different locations in Lake Michigan during 1994–1995, and lake trout diets were analyzed at all three locations. The PCB concentrations were also determined in alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), slimy sculpin (Cottus cognatus), and deepwater sculpin (Myoxocephalus thompsoni), five species of prey fish eaten by lake trout in Lake Michigan, at three nearshore sites in the lake. Despite the lack of significant differences in the PCB concentrations of alewife, rainbow smelt, bloater, slimy sculpin, and deepwater sculpin from the southeastern nearshore site near Saugatuck (Michigan) compared with the corresponding PCB concentrations from the northwestern nearshore site near Sturgeon Bay (Wisconsin), PCB concentrations in lake trout at Saugatuck were significantly higher than those at Sturgeon Bay. The difference in the lake trout PCB concentrations between Saugatuck and Sturgeon Bay could be explained by diet differences. The diet of lake trout at Saugatuck was more concentrated in PCBs than the diet of Sturgeon Bay lake trout, and therefore lake trout at Saugatuck were more contaminated in PCBs than Sturgeon Bay lake trout. These findings were useful in interpreting the long-term monitoring series for contaminants in lake trout at both Saugatuck and the Wisconsin side of the lake.

  20. Water quality of Lake Austin and Town Lake, Austin, Texas

    USGS Publications Warehouse

    Andrews, Freeman L.; Wells, Frank C.; Shelby, Wanda J.; McPherson, Emma

    1988-01-01

    Water-quality data collected from Lake Austin and Town Lake, following runoff, generally were not adequate to fully determine the effects of runoff on the lakes. Data collection should not to be limited to fixed-station sampling following runoff, and both lakes need to be sampled simultaneously as soon as possible following significant precipitation.

  1. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A., II

    2003-01-01

    Six Fathom Bank-Yankee Reef, an offshore reef complex, was an historically important spawning area believed to represent some of the best habitat for the rehabilitation of lake trout Salvelinus namaycush in Lake Huron. Since 1986, lake trout have been stocked on these offshore reefs to reestablish self-sustaining populations. We sampled with beam trawls to determine the abundance of naturally reproduced age-0 lake trout on these offshore reefs during May-July in 1994-1998 and 2000-2002. In total, 123 naturally reproduced lake trout fry were caught at Six Fathom Bank, and 2 naturally reproduced lake trout fry were caught at nearby Yankee Reef. Our findings suggest that this region of Lake Huron contains suitable habitat for lake trout spawning and offers hope that lake trout rehabilitation can be achieved in the main basin of Lake Huron.

  2. 3. Mass Movements, Erosion Patterns and Sediment Transport along the Sutlej River (NW-Himalaya)

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Thiede, R. C.; Strecker, M. R.

    2003-04-01

    The spatial and temporal distribution of mass movements in active orogens can provide valuable insights into the relation between sedimentation and erosion processes. In areas of high relief, hillslope processes dominate surface geomorphology and can lead to the damming of rivers and formation of lakes upstream. These basins provide a record of natural climatic variations along the river profile and divide the regions in different sedimentational and erosional compartments. To characterize the variations, digital elevation models were used for quantitative analysis of topography, basin-fill volume, and active channel gradients. High-resolution spatial data (digitized 1:25,000 to 1:100,000 topographic maps) and ASTER-derived digital elevation models (DEM) were processed to analyze topography. Combined with geological field measurements and observations we could distinguish erosional patterns within several study areas in the NW Himalayas. Precipitation data were derived from calibrated passive microwave satellite data (SSMI), providing information on a 10 year time series at sufficient spatial resolution (12.5 km2). Modern sediment flux and transport, discharge, geomorphic field observations including river width and slope define the boundary conditions for surface erosion calculations. The Sutlej Valley (32N, 78E) in NW India is dominated by the antecedent Sutlej River, the third-largest river in the Himalayas. It flows perpendicular through the orogen and cuts through all major geologic units of the Tethyan Himalaya, High and Lesser Himalayan Crystallines, and Lower Himalayan units. The geomorphologic changes across thrust faults bounding these units provide valuable insights into the evolution of the orogen. Tectonically active sectors of the orogen are manifested by pronounced knickpoints in longitudinal river profiles that cross active thrust faults. In contrast to other parts of the Himalayas, no (re-) activation of the MCT and STDS can be seen in the

  3. Lake whitefish and lake herring population structure and niche in ten south-central Ontario lakes

    USGS Publications Warehouse

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

    This study compares simple fish communities of ten oligotrophic lakes in south-central Ontario. Species densities and population size structure vary significantly among these lake communities depending on fish species present beyond the littoral zone. Lake whitefish are fewer and larger in the presence of lake herring than in their absence. Diet analysis indicates that lake whitefish shift from feeding on both plankton and benthic prey when lake herring are absent to a primarily benthic feeding niche in the presence of lake herring. When benthic round whitefish are present, lake whitefish size and density decline and they move lower in the lake compared to round whitefish. Burbot are also fewer and larger in lakes with lake herring than in lakes without herring. Burbot, in turn, appear to influence the population structure of benthic coregonine species. Lower densities of benthic lake whitefish and round whitefish are found in lakes containing large benthic burbot than in lakes with either small burbot or where burbot are absent. Predation on the pelagic larvae of burbot and lake whitefish by planktivorous lake herring alters the size and age structure of these populations. As life history theory predicts, those species with poor larval survival appear to adopt a bet-hedging life history strategy of long-lived individuals as a reproductive reserve.

  4. Tectonic versus climate influence on landscape evolution: A case study from the upper Spiti valley, NW Himalaya

    NASA Astrophysics Data System (ADS)

    Anoop, A.; Prasad, S.; Basavaiah, N.; Brauer, A.; Shahzad, F.; Deenadayalan, K.

    2012-04-01

    We have undertaken structural, geomorphological, and morphometric analyses to investigate the role of tectonism and climate in the landscape evolution in the upper Spiti valley, NW Himalayas. Geomorphometric analyses coupled with field investigations reveal active tectonic deformation in the Spiti region. The calculated geomorphic indices (steepness, concavity and Hack) demonstrate uplift/subsidence along the Kaurik-Chango fault, whereas transverse topographic index (T-index) reveals basin tilting associated with active faulting near Hansa and Lingti valley. Investigation of well-dated Mane palaeolake sediments also provides evidence of regional tectonic instability. Four episodes (ca. 7.8, 7.4, 6.5 and 6.1 cal ka) of neotectonic activity have been identified during the period of the lake's existence. We have also compiled data on the regional climate variability and compared it with the age of the Mane palaeo-landslide. Our results indicate that the landslide occurred towards the end of the early Holocene intensified monsoon phase and is located near an active fault. Our data on regional tectonic instability and the coincidences of modern and palaeo-landslides with zones of active deformation suggest that tectonism is an important factor governing landscape stability in the Spiti region.

  5. Late Cenozoic stress field distribution in Biga Peninsula, NW Turkey

    NASA Astrophysics Data System (ADS)

    Ozden, S.; Bekler, T.; Tutkun, S. Z.; Kurcer, A.; Ates, O.; Bekler, F. N.; Kalafat, D.

    2009-04-01

    Biga Peninsula is a seismically active region both in instrumental and historical period in NW Turkey. In this part, middle and southern branches of North Anatolian Fault are represented by Etili, Can-Biga, Yenice-Gonen, Manyas-Danisment, Lapseki, Sinekci, Terzialan, Dogruca, Uluabat, Edincik, Pazarkoy-Hamdibey-Kalkim, Edremit, Yigitler, Sarikoy-Inova, Troia and Karabiga Faults. All of these faults are responsible of the seismic activity in Biga Peninsula. Historical earthquakes happened in 29, 155, 170, 543, 620, 1440, 1737, 1855, 1865 and 1875. Furthermore, as for instrumental period, Saros Gulf-Murefte earthquakes (M:7.3 and M:6.3) in 1912, Erdek Gulf (M:6.4) and Can-Biga (M:6.3) in 1935, Edremit Gulf-Ayvaci k (M:6.8) in 1944, Yenice-Gonen (M:7.2) in 1953, Gonen (M:5.8) in 1964, Edremit-Baki rcay (M:5.5) in 1971, Biga (M:5.8) in 1983, Kusgolu-Manyas (M:5.2) and Bandirma (M:5.0) in 2006. In this study, we determined the Late Cenozoic stress field distribution and present-day tectonic regimes both fault-slip data (by 253 fault planes) and earthquake focal mechanism solutions (by 58 earthquakes) were investigated by the inversion methods. The results indicate that a transtensional stress regime is dominant with a NW-SE to WNW-ESE directed compression (1) and NE-SW to ENE-WSW directed extension (3), which yielded a NE-SW, ENE-WSW and also E-W trending strike-slip faulting faults with a normal component. While a transtensional tectonic regime has an active component in Biga Peninsula, a local and consistent transpressional tectonic regime were determined along an E-W trending narrow zone in the northern part of the Biga Peninsula also. The tectonic regime and stress field is resulted from interactions both continental collision of Eurasian/Anatolian/Arabian plate in the east and subduction processes (roll back and/or slab-pull) of the African plate along the Cyprus and Hellenic arc in the Mediterranean region.

  6. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

    USGS Publications Warehouse

    Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

    2006-01-01

    Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

  7. Yellowstone Lake Nanoarchaeota

    PubMed Central

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E.; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P.; Nealson, Kenneth; McDermott, Timothy R.

    2013-01-01

    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. PMID:24062731

  8. Whiting in Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Satellites provide a view from space of changes on the Earth's surface. This series of images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard the Orbview-2 satellite shows the dramatic change in the color of Lake Michigan during the summer. The bright color that appears in late summer is probably caused by calcium carbonate-chalk-in the water. Lake Michigan always has a lot of calcium carbonate in it because the floor of the lake is limestone. During most of the year the calcium carbonate remains dissolved in the cold water, but at the end of summer the lake warms up, lowering the solubility of calcium carbonate. As a result, the calcium carbonate precipitates out of the water, forming clouds of very small solid particles that appear as bright swirls from above. The phenomenon is appropriately called a whiting event. A similar event occured in 1999, but appears to have started later and subsided earlier. It is also possible that a bloom of the algae Microcystis is responsible for the color change, but unlikely because of Lake Michigan's depth and size. Microcystis blooms have occured in other lakes in the region, however. On the shore of the lake it is possible to see the cities of Chicago, Illinois, and Milwaukee, Wisconsin. Both appear as clusters of gray-brown pixels. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  9. Yellowstone lake nanoarchaeota.

    PubMed

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P; Nealson, Kenneth; McDermott, Timothy R

    2013-01-01

    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.

  10. 14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. ENTRANCE AT FIFTEENTH AND W STREETS, N.W., NOTE MOLDED CONCRETE FORMS, August 1976 - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

  11. 52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. VIEW LOOKING N.W. AT THE AUTOCLAVE BUILDING, PIPING FOR THE AMMONIA DISTILLATE IN FOREGROUND. MAY 21, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  12. 11. Building H9; 3/4 view, looking NW; showing relationship of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Building H-9; 3/4 view, looking NW; showing relationship of wheeling ramp to building. (Ryan and Harms) - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  13. Ecology of playa lakes

    USGS Publications Warehouse

    Haukos, David A.; Smith, Loren M.

    1992-01-01

    Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

  14. The Great Salt Lake

    USGS Publications Warehouse

    Hassibe, W.R.; Keck, W.G.

    1991-01-01

    The western part of the conterminous United States is often thought of as being a desert without any large bodies of water. In the desert area of western Utah, however, lies Great Salt Lake, which in 1986 covered approximately 2,300 square miles and contained 30 million acre-feet of water (an acre-foot is the amount of water necessary to cover 1 acre of land with water 1 foot in depth or about 326,000 gallons). To emphasize its size, the Great Salt Lake is the largest lake west of the Mississippi River, larger than the states of Rhode Island and Delaware.

  15. Soil organic matter contribution to the NW Mediterranean (Invited)

    NASA Astrophysics Data System (ADS)

    Kim, J.; Buscail, R.; Blokker, J.; Kerhervé, P.; Schouten, S.; Ludwig, W.; Sinninghe Damsté, J. S.

    2009-12-01

    The BIT (Branched and Isoprenoid Tetraether) index has recently been introduced as a proxy for soil organic matter input and is based on the relative abundance of non-isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs) derived from organisms living in terrestrial environments versus a structurally related isoprenoid GDGT “crenarchaeol” produced by marine Crenarchaeota (Hopmans et al., 2004). In this study, detailed spatial distribution patterns of BIT index were investigated in combination with other organic parameters in the continental margin of the north western Mediterranean. Based on a transect sampling strategy from source (land) to sink (sea) via river, we analysed a variety of soils from the Têt and Rhône basins, suspended particulate matter in waters of the Têt and Rhône rivers flowing into the Gulf of Lions, and marine surface sediments from the Gulf of Lions collected before and after a flood occurred in June 2008. Our study allows us to track BIT values along the transport pathway of soil organic matter and thus to estimate soil organic matter contribution in marine sediments in the Gulf of Lions (NW Mediterranean), a river-dominated continental margin. Hopmans, E.C., Weijers, J.W.H., Schefuss, E., Herfort, L., Sinninghe Damsté, J.S., Schouten, S., 2004. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoidtetraether lipids. Earth and Planetary Science Letters 224, 107-116.

  16. Tectonic deformations of the NW Novaya Zemlya Archipelago

    NASA Astrophysics Data System (ADS)

    Prokopiev, Andrei; Ershova, Victoria; Khudoley, Andrey; Sobolev, Nikolay; Petrov, Eugeniy

    2016-04-01

    The Novaya Zemlya archipelago comprises two main islands (Northern and Southern). Structural studies were conducted in the northwestern part of Northern Island, composed mainly of Upper Proterozoic-Carboniferous rocks. The structural style is dominated by NW-striking folds, clearly recognized on geological maps. The folds are typically overturned to the northwest. Southeast-dipping axial-plane cleavage is widely distributed. Tectonic transportation in Mesozoic time was directed from southeast to northwest. The bedding-cleavage intersection lineation plunges to southeast and southwest, parallel to the axes of large and small folds. The dip angle of the lineation is high, ranging up to 30o or, rarely even more. Dip angle of the intersection lineation is highly variable over a short distance, pointing to occurrence of several stages of deformation. The intersection lineation plunge angels are likely close to dip angles of bedding on the early-stage fold limbs, most of which were gentle to open ones. The early folding is presumably related to Caledonian or Ellesmerian orogenies.

  17. Assessment of Quercus flowering trends in NW Spain.

    PubMed

    Jato, V; Rodríguez-Rajo, F J; Fernandez-González, M; Aira, M J

    2015-05-01

    This paper sought to chart airborne Quercus pollen counts over the last 20 years in the region of Galicia (NW Spain) with a view to detecting the possible influence of climate change on the Quercus airborne pollen season (APS). Pollen data from Ourense, Santiago de Compostela, Vigo and Lugo were used. The Quercus airborne pollen season was characterized in terms of the following parameters: pollen season start and end dates, peak pollen count, pollen season length and pollen index. Several methods, dates and threshold temperatures for determining the chill and heat requirements needed to trigger flowering were applied. A diverse APS onset timing sequence was observed for the four cities as Quercus flowers few days in advance in Vigo. The variations observed could be related to differences in the meteorological conditions or the thermal requirements needed for flowering. Thermal requirements differed depending on local climate conditions in the study cities: the lowest values for chilling accumulation were recorded in Vigo and the highest in Lugo, whereas the lowest heat accumulation was achieved in Vigo. Differences in APS trends between cities may reflect variations in weather-related trends. A significant trend towards rising Quercus pollen indices and higher maximum daily mean pollen counts was observed in Ourense, linked to the more marked temperature increase across southern Galicia. A non-uniform trend towards increased temperatures was noted over the study period, particularly in late summer and early autumn in all four study cities. Additionally, an increase in spring temperatures was observed in south-western Galicia.

  18. The Cape Ghir filament system in August 2009 (NW Africa)

    NASA Astrophysics Data System (ADS)

    Sangrà, Pablo; Troupin, Charles; Barreiro-González, Beatriz; Desmond Barton, Eric; Orbi, Abdellatif; Arístegui, Javier

    2015-06-01

    In the framework of the Canaries-Iberian marine ecosystem Exchanges (CAIBEX) experiment, an interdisciplinary high-resolution survey was conducted in the NW African region of Cape Ghir (30°38'N) during August 2009. The anatomy of a major filament is investigated on scales down to the submesoscale using in situ and remotely sensed data. The filament may be viewed as a system composed of three intimately connected structures: a small, shallow, and cold filament embedded within a larger, deeper, and cool filament and an intrathermocline anticyclonic eddy (ITE). The cold filament, which stretches 110 km offshore, is a shallow feature 60 m deep and 25 km wide, identified by minimal surface temperatures and rich in chlorophyll a. This structure comprises two asymmetrical submesoscale (˜18 km) fronts with jets flowing in opposite directions. The cold filament is embedded near the equatorward boundary of a much broader region of approximately 120 km width and 150 m depth that forms the cool filament and stretches at least 200 km offshore. This cool region, partly resulting from the influence of cold filament, is limited by two asymmetrical mesoscale (˜50 km) frontal boundaries. At the ITE, located north of the cold filament, we observe evidence of downwelling as indicated by a relatively high concentration of particles extending from the surface to more than 200 m depth. We hypothesize that this ITE may act as a sink of carbon and thus the filament system may serve dual roles of offshore carbon export and carbon sink.

  19. Ba-rich sanidine megacrysts in trachytic rocks of Eslamy volcano, NW Iran

    NASA Astrophysics Data System (ADS)

    Aßbichler, Donjá; Asadpour, Manijeh; Heuss-Aßbichler, Soraya; Kunzmann, Thomas

    2016-04-01

    The Eslamy volcano is located on a peninsula at the eastern coast of Urumieh lake, NW Iran. The complex stratovolcano with gentle slope flanks exposes a collapsed caldera in the central part. Specific features are different sanidine rich rocks that occur in form of ejecta and flows. According to the field observations they are products of one volcanic event. XRF measurements show they all have trachytic compositions. Typical for this locality are the large sanidine phenocrysts. In the trachytic flow the sanidine crystals reach average size of ~4 cm embedded in a greenish-blue matrix consisting mainly of crystallized feldspar and subordinate pyroxen. Occasionally feldspar megacrysts of approx. 10 cm were observed. Na content of the sanidine megacrysts varies between 0.05 - 0.5 pfu with higher concentrations in the cores. Furthermore they show oscillatory zoning patterns caused by variations of Ba content (0-0.04 pfu). The matrix of the trachytic flow consist mainly of interlocking sanidine crystals (0.05-0.45 pfu Na) partly with Ba-rich cores containing up to 0.06 pfu Ba. In contrast to the megacrysts they show slightly higher Fe contents (0.025-0.035 pfu). The volcanic ejecta with bombs of approx. 50 cm in size were found in one distinct layer within a pyroclastic horizon. The average diameter of the feldspar phenocrysts is much smaller (0.5-2 cm). Sanidine is the main phase of these rocks (up to 80 %). As mafic phase up to 30 % pyroxen (mainly diospide) ± biotite can be observed. Accessories are magnetite ± apatite ± titanite ± zircon. In contrast to the flow rocks the main phase of the matrix of the ejecta is always glass with higher Fe2O3 (total) contents (up to 6 wt.-%) indicating a fast cooling of the sample due to ejection. They are completely depleted in Ba. In two samples zoned feldspar relicts enclosed in glass show remolten rims. Similar to flow rocks the feldspar phenocrysts of all ejecta show a complex zoning pattern, e.g. three samples expose high

  20. Semiquantitative multi-hazard risk assessment concepts for a himalayan watershed in NW-Bhutan

    NASA Astrophysics Data System (ADS)

    Brauner, M.; Leber, D.; Haeusler, H.; Agner, P.; Payer, T.; Tobgay, T.; Wangda, D.

    2003-04-01

    In the Pho Chhu watershed in NW-Bhutan, settlement activity concentrates on broad and pro-duc-tive valley areas, 50 to 80 kilometres downstream of glacial flood sources. Despite an time lag of 5 to 7 hours between initiation and arrival of the breach flood, the low reliability of telecommunication line results in a short pre-warning time. Upstreams, at the main Himalayan ridge, several glaciers coalescence at the valley end, forming a glacial environment with highly inter-linked, possibly hazardous glacial and gravitational processes, which also endanger small isolated settlements nearby the glaciers. Here glacial lake outbursts may be triggered by glacier surges out of water pockets, surge waves due to ice or rock fall and inherent in-stability of the moraines themselves. During flood propagation lateral gravitational processes in loose sediments and tills may result in temporal blockage. Therefore a three stage risk management concept is proposed, dividing into: (1) Local, quickly to establish countermeasures, such as technical measures with low maintenance expenditure and low failure risk, manual monitoring and improved manual telecommunication line. (2) Regional hazard zone delineation to enable hazard awareness and preparedness, and limited relocation activity. (3) And finally regional implementation of an technical early warning system. Hazard risk assessment is carried out by means of qualitative mapping of gravitative processes and quantitative process simulation of dam stability, dam breaching and flood propagation. As time series for identification of accurate time-magnitude relations are not available or questionable due to the changing environmental con-ditions, scenario modelling of the governing processes is utilised to account for process magnitude relation and process inter-linkage. Based on these procedures a semi-quantitative hazard zonation concept, taking into account quantitative process influence zones and qualitative frequency estimation has

  1. Reprocessing and Interpretation of the High Resolution Seismic Data from Northern Marmara Continental Shelf, NW Turkey

    NASA Astrophysics Data System (ADS)

    Nasif, Aslıhan; Dondurur, Derman; Ergintav, Semih; Cifci, Gunay

    2015-04-01

    The Marmara Sea is an inland sea located in the NW of Turkey with a maximum depth of 1270 m, and consists of a 3 major sub-basins. The active dextral North Anatolian Fault (NAF) passes through the basins, which shapes the general morphology and forms the tectonic settlement of the Marmara Sea. The investigations for the Marmara Sea are now important since İstanbul city, which is the most populous and economically the most important city of Turkey, is located just north of the Marmara Sea, quite close to the NAF. In order to define the morphology and structural state of the northern continental shelf of the Marmara Sea, we collected 224 km of multichannel high resolution seismic and 338 km of Chirp subbottom profiler data along the shallow shelf in 2007. A 600 m long, 96 channel digital seismic streamer, and a Generator-Injector (GI) gun was used to obtain high resolution seismic data. The Chirp data was collected a 2.75-6.75 kHz over-the-side-mount transducer system. The data have been processed using a conventional data processing flow. The scope of the present study is to re-process and to interpret the seismic and Chirp data between Silivri and Sarayburnu on the northern Marmara shelf up to 100 m water depth. The active tectonic characteristics of the area, especially its geological connection with the terrestrial area, are investigated using acoustic data. In addition, offshore continuity of the of the Çatalca Fault zone is investigated. The Çatalca Fault enters the shelf along the B. Çekmece Lake and can be tracked in the SSE direction on the seismic data. The seismic data is tied to North Marmara-1 well located on the central part of the shelf area, and distributions and thicknesses of the pre-Miocene sediments are mapped using a jump-correlation to the well information. The seismic data located at the southernmost part of the shelf along the shelf break also indicate the presence of active sediment erosion. Behind the shelf break, the slope inclination

  2. Can lake sensitivity to desiccation be predicted from lake geometry?

    NASA Astrophysics Data System (ADS)

    Torabi Haghighi, Ali; Menberu, Meseret Walle; Aminnezhad, Mousa; Marttila, Hannu; Kløve, Bjørn

    2016-08-01

    Declining lake levels (Aral Sea syndrome) can be caused by changes in climate, increased water use or changed regulation patterns. This paper introduces a novel lake geometry index (LGI) to quantify lake hydrological characteristics. The index was developed using a large representative dataset of lake hypsographic characteristics from 152 lakes and man-made reservoirs. Using the LGI index, lakes can be classified into five groups: groups 1-4 when LGI is 0.5-2.5, 2.5-4.5, 4.5-6.5 and 6.5-8.5, respectively, and group 5 when LGI is >8.5. Naturally shallow and vast lakes and wetlands fall into the first group and deep man-made reservoirs in narrow valleys are in group 5. The response of three different lake systems (LGI 0.75, 2.75 and 6.5) to different water flow scenarios was then simulated using the water balance equation. From this, the index 'potential lake area' (Apot) was developed to show lake responses to changed hydro-climatological conditions. Apot and LGI can be used to classify lakes into open or closed systems. Simulations showed that lakes with low LGI have a shorter response time to flow and climate changes. As a result, the impact of water balance restoration is faster for lakes with low LGI than for lakes with high LGI. The latter are also more vulnerable to climate variation and change.

  3. Challenges to the Lake

    EPA Science Inventory

    During the past decade we have extensively studied coastal ecosystems in the Great Lakes. Some research efforts have linked coastal receiving systems to conditions in their contributing watersheds; others have focused on developing invasive species detection and monitoring strat...

  4. Is Lake Tahoe Terminal?

    NASA Astrophysics Data System (ADS)

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.

    2014-12-01

    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

  5. Early Pleistocene lake formation and hominin origins in the Turkana-Omo rift

    NASA Astrophysics Data System (ADS)

    Lepre, Christopher J.

    2014-10-01

    Prior research has correlated the formation of Plio-Pleistocene lakes in East Africa to global/regional climate changes and interpreted the lacustrine basins as significant settings of hominin evolution. Paleo-Lake Lorenyang from the Turkana-Omo rift is important to these issues, as its marginal deposits contain some of, if not the earliest currently known specimens of Acheulian stone tools and African Homo erectus. Magnetostratigraphic and sedimentological evidence indicates that the oldest preserved paleo-Lake Lorenyang deposits are dated at 2.148-2.128 Ma and derive from the NW Turkana basin, predating those from the Omo basin by ˜100 kyr and the NE Turkana basin by ˜190 kyr. Apparently, the lake expanded asynchronously in the rift, potentially due to a volcano-tectonic influence on the location of drainage networks, depositional slopes, or topographic elevation differences within and between the basins at the time of flooding. The onset of the lake temporally coincides with the eruption of basalt lava flows dated to 2.2-2.0 Ma that blocked the southeast outlet of the Turkana basin. This provides a plausible mechanism for hydrologic closure and lacustrine basin formation through volcano-tectonic impounding. It also points to a non-climatic cause for the initial formation of paleo-Lake Lorenyang at ˜2.14 Ma. First appearances for African H. erectus (˜1.87 Ma) and Acheulian tools (˜1.76 Ma) in the Turkana-Omo rift postdate the lake's initial formation by about 270 kyr and 380 kyr, respectively. Such timing differences contrast with studies that correlate all three to the 400-kyr-eccentricity maximum at 1.8 Ma. Although the Turkana-Omo rift is just one example, it does provide alternative insights to views that link climate, hominin evolution, and lake formation in East Africa.

  6. Lake Superior, Duluth, MN

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

  7. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The fluctuating water levels of Lake Chad, (13.0N, 15.0E) at the intersection of the borders of Chad, Niger and Cameroon in the Sahara Desert, is an index of the drought in Africa. The lake level continues to decrease as indicated by the growing number and extent of emerging islands as previously submerged ancient sand dunes become visible. The water impounded between the dunes is probably because of local rainfall rather than a reversal of desertification.

  8. Overview: Ancient Lake Creede

    USGS Publications Warehouse

    Bethke, Philip M.; Hay, Richard L.

    2000-01-01

    Lake Creede was moderately saline closed-basin lake that developed in the 26.9 Ma Creede caldera in the San Juan Mountains in the southwest Colorado. The volcaniclastic sediments deposited within the late Oligocene lake were first described and named as the Creede Formation by Emmons and Larsen (1923). The lake and its sedimentary fill are of interest first as representatives of a caldera-hosted lake in a silicic volcanic terrane, and second because of the likely involvement of lake fluids or related pore waters in the deposition of the 25 Ma silver and base-metal ores of the Creede mining district north of the Creede caldera (Fig. 1), as proposed Bethke and Rye (1979). Much of the material presented in this volume is based on observation of core samples and on downhole geophysical measurements obtained as part of a U.S. Continental Scientific Drilling Program in the moat of the Creede caldera. These core and downhole studies are supplemented by outcrop studies, some initiated in support of the drilling program (Bethke and Lipman, 1987), and by conceptual studies of the evolution of the Creede caldera and its surrounding landscape. Not surprisingly, not all authors agree on all interpretation. Most disagreements are pointed out in this overview chapter, and may present opportunities for future study.

  9. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  10. Long term monitoring system integrated in an elevational gradient in NW Argentina

    NASA Astrophysics Data System (ADS)

    Carilla, J.; Malizia, A.; Osinaga, O.; Blundo, C.; Grau, R.; Malizia, L.; Aráoz, E.

    2013-05-01

    Ecological trends and ranges of variability are poorly known in the tropical and subtropical Andes. Long term studies are powerful tools to detect the response of vegetation dynamics, biodiversity and hydrological cycle to these trends. We present a long term monitoring system in NW Argentinean mountains, including forest permanent plots at different elevations and high elevation grasslands, encompassing more than 3.000 m elevation range. Long term studies include: 1) 66 ha of mountain forest permanent plots along the Yungas elevational gradient from c. 400 to 2500 masl , and latitudinal gradient (22-28S) with 45 plots in mature forests and 28 in secondary forests originated in grazing, agriculture and selective logging. Some of these permanent plots have achieved 20 years of monitoring and all of them are included in the "Red de Bosques Andinos" a network created recently, together with c. 10 institutions and more than 130 (c. 120 ha) forest permanent plots from Argentina to Colombia Andes. 2) Two GLORIA (Global Observation Research Initiative in Alpine Environments) sites, above 4000 masl with more than 170 species recorded, including one re-measurement. This system is included in GLORIA network (www.gloria.ac.at) and in GLORIA Andes (http://www.condesan.org/gloria), and 3) more than 15 satellite monitored high Andean lakes and a wide extension of vegas (75800 ha in Argentinean puna). A digital database is being implemented to organize and provide access to the information generated by these three systems coordinated by the Instituto de Ecología Regional (http://www.iecologia.com.ar). These monitoring data are analyzed together with instrumental and dendrochronological data to describe the dynamics of these ecosystems over an area of 20 million hectares distributed between 22 and 28°S. Some of the most significant results to date include: 1) secondary mountain forests are expanding over grasslands and agriculture lands, and tend to converge toward mature forest

  11. Is Lake Chabot Eutrophic?

    NASA Astrophysics Data System (ADS)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

  12. Recent Increases in Snow Accumulation and Decreases in Sea-Ice Concentration Recorded in a Coastal NW Greenland Ice Core

    NASA Astrophysics Data System (ADS)

    Osterberg, E. C.; Thompson, J. T.; Wong, G. J.; Hawley, R. L.; Kelly, M. A.; Lutz, E.; Howley, J.; Ferris, D. G.

    2013-12-01

    A significant rise in summer temperatures over the past several decades has led to widespread retreat of the Greenland Ice Sheet (GIS) margin and surrounding sea ice. Recent observations from geodetic stations and GRACE show that ice mass loss progressed from South Greenland up to Northwest Greenland by 2005 (Khan et al., 2010). Observations from meteorological stations at the U.S. Thule Air Force Base, remote sensing platforms, and climate reanalyses indicate a 3.5C mean annual warming in the Thule region and a 44% decrease in summer (JJAS) sea-ice concentrations in Baffin Bay from 1980-2010. Mean annual precipitation near Thule increased by 12% over this interval, with the majority of the increase occurring in fall (SON). To improve projections of future ice loss and sea-level rise in a warming climate, we are currently developing multi-proxy records (lake sediment cores, ice cores, glacial geologic data, glaciological models) of Holocene climate variability and cryospheric response in NW Greenland, with a focus on past warm periods. As part of our efforts to develop a millennial-length ice core paleoclimate record from the Thule region, we collected and analyzed snow pit samples and short firn cores (up to 20 m) from the coastal region of the GIS (2Barrel site; 76.9317 N, 63.1467 W) and the summit of North Ice Cap (76.938 N, 67.671 W) in 2011 and 2012, respectively. The 2Barrel ice core was sampled using a continuous ice core melting system at Dartmouth, and subsequently analyzed for major anion and trace element concentrations and stable water isotope ratios. Here we show that the 2Barrel ice core spanning 1990-2010 records a 25% increase in mean annual snow accumulation, and is positively correlated (r = 0.52, p<0.01) with ERA-Interim precipitation. The 2Barrel annual sea-salt Na concentration is strongly correlated (r = 0.5-0.8, p<0.05) with summer and fall sea-ice concentrations in northern Baffin Bay near Thule (Figure 1). We hypothesize that the positive

  13. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    EPA Science Inventory

    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.

  14. Availability of lake trout reproductive habitat in the Great Lakes

    USGS Publications Warehouse

    Edsall, Thomas A.; Kennedy, Gregory W.

    1995-01-01

    A decades-long program to reestablish self-sustaining stocks of lake trout (Salvelinus namaycush) in the four lower Great Lakes produced excellent fisheries supported by stocked fish. These fish spawned widely and small numbers of their offspring were collected intermittently from Lakes Michigan, Huron, and Ontario, but no self-sustaining stocks were established. Irt this paper we address habitat sufficiency as a factor in the failure of stocked lake trout to established self-sustaining populations in the four lower Great Lakes. We present the previously unpublished results of lake trout spawning habitat surveys conducted at seven sites in the Great Lakes since 1987 and we compare them with the published results of similar surveys conducted at 24 other sites in the four lower lakes since 1981. Our evaluation indicates all but two of these sites can support the production of viable fry from spawnings by the shallow-water strains of lake trout that are stocked in the Great Lakes. However, some of the best spawning, egg, and fry habitat in the lower Great Lakes seems to be at deeper offshore sites that may be unattractive to these shallow-water strains. Thus, we suggest also stocking the lower four lakes with strains from Lake Superior that might more fully exploit the best spawning habitat at these deeper, offshore sites.

  15. Grounding zone wedges, Kveithola Trough (NW Barents Sea)

    NASA Astrophysics Data System (ADS)

    Rebesco, Michele; Urgeles, Roger; Özmaral, Asli; Hanebuth, Till; Caburlotto, Andrea; Hörner, Tanja; Lantzsch, Hendrik; LLopart, Juame; Lucchi, Renata; Skøtt Nicolaisen, Line; Giacomo, Osti; Sabbatini, Anna; Camerlenghi, Angelo

    2014-05-01

    Swath bathymetry within Kveithola Trough (NW Barents Sea) shows a seafloor characterized by E-W trending megascale glacial lineations (MSGLs) overprinted by transverse Grounding Zone Wedges (GZWs), which give the trough a stair profile (Rebesco et al., 2011). GZWs are formed by deposition of subglacial till at temporarily stable ice-stream fronts in between successive episodic retreats (Rüther et al., 2012; Bjarnadóttir et al., 2012). Sub-bottom data show that present-day morphology is largely inherited from palaeo-seafloor topography of GZWs, which is draped by a deglacial to early Holocene glaciomarine sediments (about 15 m thick). The ice stream that produced such subglacial morphology was flowing from East to West inside Kveithola Trough during Last Glacial Maximum. Its rapid retreat was likely associated with progressive lift-offs, and successive rapid melting of the grounded ice, induced by the eustatic sea-level rise (Lucchi et al., 2013). References: Bjarnadóttir, L.R., Rüther, D.C., Winsborrow, M.C.M., Andreassen, K., 2012. Grounding-line dynamics during the last deglaciation of Kveithola, W Barents Sea, as revealed by seabed geomorphology and shallow seismic stratigraphy. Boreas, 42, 84-107. Lucchi R.G., et al. 2013. Postglacial sedimentary processes on the Storfjorden and Kveithola TMFs: impact of extreme glacimarine sedimentation. Global and Planetary Change, 111, 309-326. Rebesco, M., et al. 2011. Deglaciation of the Barents Sea Ice Sheet - a swath bathymetric and subbottom seismic study from the Kveitehola Trough. Marine Geology, 279, 141-14. Rüther, D.C., Bjarnadóttir, L.R., Junttila, J., Husum, K., Rasmussen, T.L., Lucchi, R.G., Andreassen, K., 2012. Pattern and timing of the north-western Barents Sea Ice Sheet deglaciation and indications of episodic Holocene deposition. Boreas 41, 494-512.

  16. Mesozooplankton metabolism and feeding in the NW Iberian upwelling

    NASA Astrophysics Data System (ADS)

    Isla, José Alejandro; Ceballos, Sara; Anadón, Ricardo

    2004-09-01

    Mesozooplankton size-fractionated biomass, feeding, and metabolic rates were investigated during a cruise conducted off NW Spain in August 1998. Based on different hydrographic conditions observed throughout the study area (upwelling events nearshore and stratified waters offshore), the sampling area was divided into coastal and oceanic zones. Both phytoplankton and mesozooplankton biomass were higher in the coastal upwelling than in the offshore zone. Size structure analysis shows that the small fraction (200-500 μm) of mesozooplankton was more important than the larger fractions (500-1000 μm and >1000 μm) in the open ocean in terms of both biomass and grazing activity. The relationship between copepod ingestion rate and the concentration of chlorophyll a >5 μm resembled a type II functional response. Saturation occurred at the coastal stations, where copepod gut contents were highest. The grazing impact on both phytoplankton biomass and primary production seemed to be higher offshore (5.7 and 12.9%, respectively) than in upwelled waters (5.2 and 5.2%), although the differences were not statistically significant. Phytoplankton ingestion was enough to fulfil the basal metabolism of mesozooplankton in the upwelling area (102.1% of the minimum carbon requirements met) but not in the offshore (45.9%). Feeding activity and metabolic measurements on mesozooplankton point to a herbivorous food web in the coastal upwelling zone and a multivorous food web in the stratified open oceanic waters. The amount of metabolic end products released by mesozooplankton was higher in the coastal zone, but mesozooplankton played a more important role as nutrient regenerators in the multivorous food web (30.3 and 21.7% of the nitrogen and phosphorus phytoplankton demand accounted for ammonium and phosphate excretion, respectively) than in the herbivorous one (3.8% for ammonium and 2.6% for phosphate).

  17. Petrography, palynology and depositional environment of Gelibolu coals, NW Turkey

    NASA Astrophysics Data System (ADS)

    Demirtaş, Ferdi; Bozcu, Mustafa; Koşun, Erdal

    2014-05-01

    Upper Oligocene and Miocene coal samples collected from two outcrops in the Gelibolu Peninsula, NW Turkey were analyzed petrographically and palynologically to determine the depositional environment of the coals. Microscopic studies reveal that the studied coal samples from both locations are characterized by high amount of huminite group macerals, ranging from 46 to 78% (mineral-included basis). The prevailing maceral from this group is gelinite (31-65%), it can be easily seen on all studied samples, indicative of high gelification degree of organic matter. Relatively low amount of liptinite (does not exceed 9%) and inertinite (does not exceed 8%) are also observed in the coals. The mineral matter content is variable but generally high, varying from 5 to 37%, as in other Turkish coals and consists mostly of clay minerals, quartz, calcite and pyrite. The mean reflectance values range from 0.502 to 0.564% suggesting that rank of coal is subbituminous (ASTM). The chemical properties of coal including calorific value, volatile matter and fixed carbon content are also in accordance with rank of coal. Facies indices based on maceral ratios (Tissue Preservation Index vs. Gelification Index and ABC ternary diagrams) were used to interpret to depositional environment of coals. Low tissue preservation index (TPI) and high gelification index (GI) values are observed. These indices indicate that the coals deposited in limnic environment. High pH and strongly reducing conditions inferred from the presence of framboidal pyrite and also evidenced by low TPI values. The palynological assembly of the coals dominated by angiosperm pollen and spore, however, gymnosperms were rarely seen. Herbaceous/sedge plants are common in Miocene coal samples.

  18. Earthquakes, Uplift, and Landscape Evolution in the NW Himalayas

    NASA Astrophysics Data System (ADS)

    Shahzad, F.; Mahmood, S.; Gloaguen, R.

    2009-05-01

    The terrain between Main Mantle Thrust to Salt Range Thrust in the NW Himalayas has been characterized by surface and subsurface features with variable tectonic activity. These features show relatively variable tectonic activity, existence of blind faults and basement faulting. In the present study, we use seismological and remote sensing analysis backed by field observations to investigate the relationship between earthquakes, uplift, and landscape evolution. We use nonlinear analysis to understand the earthquake dynamics in relation to surface faults and blind faults. The fractal analysis of the seismicity in three subsurface features of the area is used to characterize the roughness of the faults' surface. We find a high fault surface roughness in the Indus Kohistan Seismic Zone (IKSZ). It is concluded that the area is in the process of being uplifted and landscape is evolving. This evolution is further investigated using a set of geomorphological analyses consisting of extracting a drainage network from digital elevation models (DEM). The extracted streams are analysed using to calculate geomorphic indices and relative uplift rates. These analyses were applied on Indus, Swat, Kabul, Kunhar, Kishanganga, Poonch, Jehlum, Swan and Kurram, Kabul Rivers and their associate tributaries. The analyses provide us with the spatial variation of relative uplift based upon specific streams. We found that the Hazara Kashmir Syntaxis and Nanga Parbat Haramosh Massif are subject to a relatively high uplift. It is observed that the neotectonic activities are linearizing the drainage network from meandering pattern. We analyse the complete drainage texture using fractal dimension and lacunarity analysis. The analysis of the fractal dimension (D) employing box counting methods is calculated with a moving window approach and the lower values of D demonstrate the effect of neotectonic activity. The locations with lower but similar D values are further differentiated using

  19. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    PubMed

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin. PMID:25970617

  20. ERUPTIVE VARIABLE STARS AND OUTFLOWS IN SERPENS NW

    SciTech Connect

    Hodapp, Klaus W.; Chini, Rolf; Watermann, Ramon; Lemke, Roland

    2012-01-01

    We study the outflow activity, photometric variability, and morphology of three very young stellar objects in the Serpens NW star-forming region: OO Serpentis, EC 37 (V370 Ser), and EC 53 (V371 Ser). High spatial resolution Keck/NIRC2 laser guide star adaptive optics images obtained in 2007 and 2009 in broadband K and in a narrowband filter centered on the 1-0 S(1) emission line of H{sub 2} allow us to identify the outflows from all three objects. We also present new, seeing-limited data on the photometric evolution of the OO Ser reflection nebula and re-analyze previously published data. We find that OO Ser declined in brightness from its outburst peak in 1995 to about 2003, but that this decline has recently stopped and actually reversed itself in some areas of the reflection nebula. The morphology and proper motions of the shock fronts MHO 2218 near EC 37 suggest that they all originate in EC 37 and that this is an outflow seen nearly along its axis. We identify an H{sub 2} jet emerging from the cometary nebula EC 53. The star illuminating EC 53 is periodically variable with a period of 543 days and has a close-by, non-variable companion at a projected distance of 92 AU. We argue that the periodic variability is the result of accretion instabilities triggered by another very close, not directly observable, binary companion and that EC 53 can be understood in the model of a multiple system developing into a hierarchical configuration.

  1. DENSITY VARIATIONS IN THE NW STAR STREAM OF M31

    SciTech Connect

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W. E-mail: richer@astro.ubc.ca

    2011-04-20

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10{sup -5}. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study.

  2. Timing and Spatial Distribution of Loess in Xinjiang, NW China

    PubMed Central

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess–paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin. PMID:25970617

  3. Timing and Spatial Distribution of Loess in Xinjiang, NW China.

    PubMed

    Li, Yun; Song, Yougui; Yan, Libin; Chen, Tao; An, Zhisheng

    2015-01-01

    Central Asia is one of the most significant loess regions on Earth, with an important role in understanding Quaternary climate and environmental change. However, in contrast to the widely investigated loess deposits in the Chinese Loess Plateau, the Central Asian loess-paleosol sequences are still insufficiently known and poorly understood. Through field investigation and review of the previous literature, the authors have investigated the distribution, thickness and age of the Xinjiang loess, and analyzed factors that control these parameters in the Xinjiang in northwest China, Central Asia. The loess sediments cover river terraces, low uplands, the margins of deserts and the slopes of the Tianshan Mountains and Kunlun Mountains and are also present in the Ili Basin. The thickness of the Xinjiang loess deposits varies from several meters to 670 m. The variation trend of the sand fraction (>63 μm) grain-size contour can indicate the local major wind directions, so we conclude that the NW and NE winds are the main wind directions in the North and South Xinjiang, and the westerly wind mainly transport dust into the Ili basin. We consider persistent drying, adequate regional wind energy and well-developed river terraces to be the main factors controlling the distribution, thickness and formation age of the Xinjiang loess. The well-outcropped loess sections have mainly developed since the middle Pleistocene in Xinjiang, reflecting the appearance of the persistent drying and the present air circulation system. However, the oldest loess deposits are as old as the beginning of the Pliocene in the Tarim Basin, which suggests that earlier aridification occurred in the Tarim Basin rather than in the Ili Basin and the Junggar Basin.

  4. A study of petroleum system in Chuhuangkeng anticline, NW Taiwan

    NASA Astrophysics Data System (ADS)

    Yiang, S.; Tsai, L. Y.

    2015-12-01

    Since energy demand is still increasing in the world, the exploration of unconventional fossil fuel becomes more and more important today. Miaoli area of the NW Western Foothill Belt, Taiwan, had been a major oil and gas producing field in the past, important oil/gas producing structures include Tiechenshen, Chinshui and Chuhuangkeng anticline. The reservoir rocks of unconventional resources need to be examined to illustrate the remaining hydrocarbon potential of Chuhuangkeng anticline. A standard evaluation procedure for assessing integrated geochemical parameters can thus be established. In this study, we combine various geochemical parameters including TOC, porosity, Rock-Eval pyrolysis, vitrinite reflectance measurement to assess the HC potential of shale gas reservoirs. The results show that Wuchishan and Mushan Formations possess the best hydrocarbon potential in Chuhuangkeng anticline. The maturation of Wuchishan and Mushan Formations are both in oil window (Ro of Wuchishan formation =1.7% , Ro of Mushan =1.01~1.53% ). The maturation of Shitih Formation barely reached oil window, however the shallower depth and less exploration cost are the advantages of Shitih Formation. Moreover, Wuchishan Formation is a dry gas field and Mushan Formation is a condensate gas field. The results of porosity show that there are secondary porosity existed in Mushan Formation which provides the extra storage space for hydrocarbon. Additionally, Piling Shale is a good cap rock on top of Mushan formation, it further benefits the conservation of oil and gas in Mushan Formation. In conclude, Mushan Formation is the most potential HC target in future shale gas exploration.

  5. Deformation and Fluid Flow in the Etendeka Plateau, NW Namibia

    NASA Astrophysics Data System (ADS)

    Salomon, Eric; Koehn, Daniel; Passchier, Cees; Davis, Jennifer; Salvona, Aron; Chung, Peter

    2014-05-01

    We studied deformation bands in sandstone and breccia veins in overlying basalts of the Etendeka Plateau, NW Namibia, regarding their development and history of fluid flow within. The studied deformation bands can be divided into disaggregation bands and cataclastic bands. The former appear to develop in unsorted sandstone, whereas the latter form in well sorted sandstone. We estimated the porosity of the bands and host rock in thin sections using a simple image analysis software (ImageJ). Results show, that no or only a minor decrease in porosity occur in disaggregation bands, while the porosity in cataclastic bands is decreased by up to 82 % with respect to the host rock. These observations are in agreement with results of existing studies (e.g. Fossen et al., 2007). Hence the cataclastic bands form a seal to fluid flow in the host rock, yet it is observed in outcrops that deformation bands can develop into open fractures which in turn increase the permeability of the rock. Breccia veins in the overlying basalts show intense fracturing where the basalt is locally fractured into elongated chips. Mineral precipitation in these breccia veins indicates a hydrothermal origin of the fluids since the precipitates consist of extremely fine-grained quartz aggregates. Secondary mineralization with large crystals indicates that a long-lived fluid circulation through tubular networks was active at a later stage, which eventually sealed the veins completely. We propose that the Etendeka basalts on top of the sandstone formation produced a localized deformation along deformation bands and heated up fluid below the lavas. At a later stage fluid pressures were either high enough to break through the basalt or fracturing due to ongoing extension produced fluid pathways. References Fossen, H., Schultz, R., Shipton, Z. and Mair, K. (2007). Deformation bands in sandstone: a review. J. Geol. Soc., 164, 755-769.

  6. The Pliocene-Pleistocene sedimentary tectonic history of NW California

    SciTech Connect

    Stone, L.; Moley, K.; Aalto, K.R. . Dept. of Geology); Renne, P.R. . Berkeley Geochronology Center)

    1993-04-01

    A thick sequence of Late Miocene to Pleistocene sediments thought to represent deposition in a Neogene forearc basin are preserved in the structural basin referred to as the Eel River basin' located offshore of NW California and SE Oregon. The southern portion of this structural basin comes on land in the vicinity of Eureka where the marine and fluvial Wildcat Group is exposed. Basal Wildcat Group sediments are fluvial and littorial. Marine sandstones of the Wildcat Group contain K-spar concentrations of 5.5% and are believed to represent a fresh source. [sup 40]Ar/[sup 39]Ar laser probe analyses of Wildcat Group micas yield dates of 52--57, 66--75, 128.5 and 299--303 Ma. The presence of Idaho detritus throughout the Neogene Wildcat Group indicates that the Klamath Mountains remained low during the Pliocene and early Pleistocene. Younger fluvial sediments in this region contain primarily locally derived detritus indicating local uplift of the Klamath Mountains. To the north, at Crescent City, thin remnants of the near-shore Saint George Formation and the eastern estuarine and fluvial Wimer Formation are lowermost Pliocene in age (5 ma). The presence of the highly erodible Wilmer Formation on uplifted plateaus in an area of extreme rainfall suggest that these sediments represent only the lowermost portion of an originally much thicker sequence. Consequently, the sediments confined to the present day Eel River basin do not represent the lateral extent of the original forearc basin. Sandstones and conglomerates of the Saint George and Wimer Formation indicate a local Klamath provenance derivation.

  7. Density Variations in the NW Star Stream of M31

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Richer, Harvey B.; McConnachie, Alan W.; Irwin, Mike; Ibata, Rodrigo A.; Dotter, Aaron L.; Chapman, Scott; Fardal, Mark; Ferguson, A. M. N.; Lewis, G. F.; Navarro, Julio F.; Puzia, Thomas H.; Valls-Gabaud, David

    2011-04-01

    The Pan Andromeda Archeological Survey (PAndAS) CFHT Megaprime survey of the M31-M33 system has found a star stream which extends about 120 kpc NW from the center of M31. The great length of the stream, and the likelihood that it does not significantly intersect the disk of M31, means that it is unusually well suited for a measurement of stream gaps and clumps along its length as a test for the predicted thousands of dark matter sub-halos. The main result of this paper is that the density of the stream varies between zero and about three times the mean along its length on scales of 2-20 kpc. The probability that the variations are random fluctuations in the star density is less than 10-5. As a control sample, we search for density variations at precisely the same location in stars with metallicity higher than the stream [Fe/H] = [0, -0.5] and find no variations above the expected shot noise. The lumpiness of the stream is not compatible with a low mass star stream in a smooth galactic potential, nor is it readily compatible with the disturbance caused by the visible M31 satellite galaxies. The stream's density variations appear to be consistent with the effects of a large population of steep mass function dark matter sub-halos, such as found in LCDM simulations, acting on an approximately 10 Gyr old star stream. The effects of a single set of halo substructure realizations are shown for illustration, reserving a statistical comparison for another study. Based on observations obtained with MegaPrime / MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  8. Contaminants in American alligator eggs from Lake Apopka, Lake Griffin, and Lake Okeechobee, Florida

    USGS Publications Warehouse

    Heinz, G.H.; Percival, H.F.; Jennings, Michael L.

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A larger sample of eggs was collected in 1985, but only from Lakes Griffin, a lake where eggs were relatively clean, and Apopka, where eggs were most contaminated. In 1985, hatching success of artificially incubated eggs was lower for Lake Apopka, and several organochlorine pesticides were higher than in eggs from Lake Griffin. However, within Lake Apopka, higher levels of pesticides in chemically analyzed eggs were not associated with reduced hatching success of the remaining eggs in the clutch. Therefore, it did not appear that any of the pesticides we measured were responsible for the reduced hatching of Lake Apopka eggs.

  9. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex

    USGS Publications Warehouse

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.

    2006-01-01

    The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry, and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

  10. Big lake records preserved in a little lake's sediment: An example from Silver Lake, Michigan, USA

    USGS Publications Warehouse

    Fisher, T.G.; Loope, W.L.; Pierce, W.; Jol, H.M.

    2007-01-01

    We reconstruct postglacial lake-level history within the Lake Michigan basin using soil stratigraphy, ground-penetrating radar (GPR), sedimentology and 14C data from the Silver Lake basin, which lies adjacent to Lake Michigan. Stratigraphy in nine vibracores recovered from the floor of Silver Lake appears to reflect fluctuation of water levels in the Lake Michigan basin. Aeolian activity within the study area from 3,000 years (cal yr. B.P.) to the present was inferred from analysis of buried soils, an aerial photograph sequence, and GPR. Sediments in and around Silver Lake appear to contain a paleoenvironmental record that spans the entire post-glacial history of the Lake Michigan basin. We suggest that (1) a pre-Nipissing rather than a Nipissing barrier separated Silver Lake basin from the Lake Michigan basin, (2) that the Nipissing transgression elevated the water table in the Silver Lake basin about 6,500 cal yr. B.P., resulting in reestablishment of a lake within the basin, and (3) that recent dune migration into Silver Lake is associated with levels of Lake Michigan.

  11. High Resolution Environmental Magnetic Study of a Holocene Sedimentary Record from Zaca Lake, Ca

    NASA Astrophysics Data System (ADS)

    Platzman, E. S.; Lund, S.; Kirby, M. E.; Feakins, S. J.

    2012-12-01

    Magnetic studies of Holocene lake sediments recovered from Zaca lake have yielded a 3000-year high resolution record of environmental variability and paleolimnology. Zaca lake is a small oligomictic lake ~12m deep situated 730 m above sea level in the steep canyons of the San Rafael mountains, NW of Santa Barbara. Throughout much of the year Zaca lake is anaerobic below 7m. Hydrogen sulfide, fed into the lake via runoff and local sulphur springs, is present throughout the hypolimnion with concentrations sometime exceeding 30 mg/ l. During the summer months when the lake is stratified, light colored carbonate rich microlaminae are formed; and often during the winter months when the lake overturns, killing the anaerobic bacteria, black microlamina rich in iron sulfide are deposited on the lake floor, creating a stratigraphy reflecting patterns of environmental variability on annual to millennial scales. Samples for magnetic analysis were obtained from 8.5 m of core recovered from the central region of Zaca lake. Ages, constrained using radiocarbon chronostratigraphy, yielded sedimentation rates of 2-10 mm/yr with an average rate of 3 mm per yr over the 3000 yr interval. Parameters reflecting decadal scale variability in magnetic concentration (susceptibility, ARM, SIRM) and grainsize (ARM/Chi) were measured every 2 cm. Additional rock magnetic tests, including thermal demagnetization of three component IRM, were applied at selected intervals to constrain the magnetic mineralogy. These data were combined with analyses of clastic grain size, % calcium carbonate and % organics to create a multiproxy record of environmental variability. Results show that Zaca lake has had a complex depositional history. Anthropogenic effects associated with European colonization are present in the upper meters. Most notable, however, is a dramatic shift in the magnetic parameters and mineralogy between the upper and lower half of the core (circa 1300 ybp) indicating a shift in regime

  12. Winter Lake Breezes near the Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Crosman, Erik T.; Horel, John D.

    2016-05-01

    Case studies of lake breezes during wintertime cold air pools in Utah's Salt Lake Valley are examined. While summer breezes originating from the Great Salt Lake are typically deeper, of longer duration, and have higher wind speeds than winter breezes, the rate of inland penetration and cross-frontal temperature differences can be higher during the winter. The characteristics of winter breezes and the forcing mechanisms controlling them (e.g., snow cover, background flow, vertical stability profile, clouds, lake temperature, lake sheltering, and drainage pooling) are more complex and variable than those evident in summer. During the afternoon in the Salt Lake Valley, these lake breezes can lead to elevated pollution levels due to the transport of fine particle pollutants from over the Great Salt Lake, decreased vertical mixing depth, and increased vertical stability.

  13. Movements of adult lake trout in Lake Superior

    USGS Publications Warehouse

    Rahrer, Jerold F.

    1968-01-01

    Returns from mature lake trout (Salvelinus namaycush) tagged in western Lake Superior in 1959 and 1962-65 described here suggest that trout disperse widely from the spawning grounds after spawning and return in subsequent years. Although the data were not extensive, returns from lake trout tagged near Keweenaw Point in 1950 and off Marquette, Michigan, in 1952 suggested similar movement. Loftus stated that river-spawning lake trout of eastern Lake Superior returned annually to the same spawning streams. Movements of lake trout must be understood to manage and evaluate the rehabilitation of lake trout stocks in Lake Superior, especially when the trout move across interstate and international boundaries and are subject to different fishing regulations and fishing pressures.

  14. Crater Lake revealed

    USGS Publications Warehouse

    Ramsey, David W.; Dartnell, Peter; Bacon, Charles R.; Robinson, Joel E.; Gardner, James V.

    2003-01-01

    Around 500,000 people each year visit Crater Lake National Park in the Cascade Range of southern Oregon. Volcanic peaks, evergreen forests, and Crater Lake’s incredibly blue water are the park’s main attractions. Crater Lake partially fills the caldera that formed approximately 7,700 years ago by the eruption and subsequent collapse of a 12,000-foot volcano called Mount Mazama. The caldera-forming or climactic eruption of Mount Mazama drastically changed the landscape all around the volcano and spread a blanket of volcanic ash at least as far away as southern Canada. Prior to the climactic event, Mount Mazama had a 400,000 year history of cone building activity like that of other Cascade volcanoes such as Mount Shasta. Since the climactic eruption, there have been several less violent, smaller postcaldera eruptions within the caldera itself. However, relatively little was known about the specifics of these eruptions because their products were obscured beneath Crater Lake’s surface. As the Crater Lake region is still potentially volcanically active, understanding past eruptive events is important to understanding future eruptions, which could threaten facilities and people at Crater Lake National Park and the major transportation corridor east of the Cascades. Recently, the lake bottom was mapped with a high-resolution multibeam echo sounder. The new bathymetric survey provides a 2m/pixel view of the lake floor from its deepest basins virtually to the shoreline. Using Geographic Information Systems (GIS) applications, the bathymetry data can be visualized and analyzed to shed light on the geology, geomorphology, and geologic history of Crater Lake.

  15. The Wandering Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In the area at the very far eastern corner of China's Taklimakan Desert, Lop Nor Lake was located up until some years ago. Lop Nor, also called the 'the heart of the heart' of Asia, was the place where the waters of the largest inner basin (i.e., not flowing into the sea) of the world-including the Tarim and Kum-daria Rivers-were collected. Depending on the balance between rainfall water yield and evaporation, both position and size of the lake were strongly variable, thus giving rise to the legend of the Wandering Lake. 'Lop City' was the place where Marco Polo took his last rest before facing the one-year long crossing of the Gobi Desert. Starting from the end of the 19th century, several explorers tried to find the legendary place. One such explorer was Sven Hedin, who was commissioned by the Governor of Nanjing to lead an expedition to find the lake. In 1937, the Swedish explorer published his book entitled The Wandering Lake. Comparing this very precise map from Sven Hedin's book with the above Moderate-resolution Imaging Spectroradiometer (MODIS) false-color image (acquired on October 28, 2001), one can find a faint sign on the soil where the Lop Nor was located. This image, derived using a combination of MODIS' near-infrared and red channels (vegetation in red), shows where the Tarim River waters currently end their flow. The Wandering Lake does not exist anymore. The combination of climate change and human exploitation of water resources for agriculture caused the disappearance of the lake. This image was processed by Telespazio, Earth Observation division, new products development facility in Rome, Italy. The MODIS sensor flies aboard NASA's Terra spacecraft, launched in December 1999. Caption and image courtesy Luca Pietranera, Telespazio, Rome, Italy, based on data from the MODIS Science Team

  16. The Quaternary Tahoe-Medicine Lake trough: The western margin of the Basin and Range transition, NE California

    SciTech Connect

    Page, W.D. . Geoscience Dept.); Sawyer, T.L. ); Mclaren, M.K.; Savage, W.U.; Wakabayashi, J.

    1993-04-01

    The Tahoe-Medicine Lake trough is a series of small right-stepping, en echelon tectonic depressions that extend 400 km NNW from Lake Tahoe to near the Oregon border. The trough developed since the Miocene, and forms the eastern edge of the Sierra Nevada and southern Cascade Mountains, and the western boundary of the Plumas province and Modoc Plateau, which are transitional to the Basin and Range. The geomorphic expression of the trough indicates late Pleistocene and Holocene fault activity along its length. The continuity of the structure, however, has been masked in places by volcanic deposits that have filled or partly filled the tectonic lows. Moderate historical earthquakes (M5-6) have occurred only along the southern trough. Microearthquakes prominently follow the trough from Lake Tahoe north [omega] Lake Almanor. From there northward, seismicity patterns are predominantly shallow (<5 km) volcanic-related clusters at Mt. Lassen, Medicine Lake, and Tennent and Stephens passes. Geologic and seismicity data indicate that the NW-trending south-central section has a significant component of right-slip, which appears to be related to the Walker Lane shear zone. To the south, the trough is the NNW-striking, 10- to 20-km-wide Tahoe depression, which extends from Lake Tahoe to the Sierra Valley and is partly filled with Quaternary volcanic deposits near Truckee. The escarpment and probable displaced moraines along this section indicate late Pleistocene and possibly Holocene activity. Seismicity is diffuse except in the vicinity of the 1966 Truckee earthquake (M6.0). Northward, from Sierra Valley to American Valley, the trough changes trend to the NW, and is the 6-km-wide Plumas trench, which down-faults the Mehrten Fm. (Miocene to early Pliocene) about 1,000 m.

  17. Examining indirect effects of lake trout recovery

    EPA Science Inventory

    With the recovery of lake trout populations in Lake Superior, there are indications of decreased forage fish abundance and density-dependence in lake trout. In Lake Superior, lean lake trout historically occupied depths < 60 m, and siscowet lake trout occupied depths > 60 m...

  18. 42. Peaks of Otter, Abbott Lake. View across lake to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. Peaks of Otter, Abbott Lake. View across lake to peaks of Outter Lodge, completed in 1964. Construction of the lake got underway in 1964. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  19. National Lakes Assessment: A Collaborative Survey of the Nation's Lakes

    EPA Science Inventory

    The National Lakes Assessment A Collaborative Survey of the Nation's Lakes presents the results of an unprecedented assessment of the nation’s lakes. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed to provide the pub...

  20. Lake Michigan lake trout PCB model forecast post audit

    EPA Science Inventory

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  1. ERS-1 SAR backscatter changes associated with ice growing on shallow lakes in Arctic Alaska

    NASA Technical Reports Server (NTRS)

    Jeffries, M. O.; Wakabayashi, H.; Weeks, W. F.

    1993-01-01

    Spatial and temporal backscatter intensity (sigma(sup o)) variations from ice growing on shallow lakes during winter 1991-92 near Barrow, NW Alaska, have been quantified for the first time using ERS-I C-band SAR data acquired at the Alaska SAR Facility. A field and laboratory validation program, including measurements of the thickness and structure-stratigraphy of the ice, indicates that sigma(sup o) values are strongly dependent on whether the ice freezes to the lake bottom, or remains afloat. Backscatter intensity decreases significantly when the ice grounds on the bottom. Strong backscatter from floating ice is attributed to a specular ice-water interface and vertically oriented tubular bubbles. During the spring thaw, backscatter undergoes a reversal; sigma(sup o) values from ice that was grounded increase, while sigma(sup o) values from ice that was afloat decrease. This phenomenon has not previously been reported.

  2. The April-June 2007 Trichonis Lake earthquake swarm (W. Greece): New implications toward the causative fault zone

    NASA Astrophysics Data System (ADS)

    Kassaras, I.; Kapetanidis, V.; Karakonstantis, A.; Kaviris, G.; Papadimitriou, P.; Voulgaris, N.; Makropoulos, K.; Popandopoulos, G.; Moshou, A.

    2014-01-01

    On 10 April 2007, three moderate earthquakes with Mw = 4.9-5.1 occurred in the vicinity of Trichonis Lake (W. Greece). A local network composed of 12 three-component digital seismographs was installed in the epicentral area and recorded more than 1600 events. The double-difference algorithm HYPODD, incorporating both catalog and waveform cross-correlation differential travel-time data, was applied for the successful relocation of 1490 earthquakes. The latter led to the distinction of a main NW-SE trending and NE-dipping zone, as well as of three neighboring faults; a conjugate NW-SE striking and SW-dipping marginal fault mapped along the northeastern flanks of the lake; a E-W trending and south-dipping low-angle normal fault, possibly related to the major Agrinio Fault Zone (AFZ), parallel to the northern bank of the lake; a NE-SW striking and NW-dipping normal fault, likely related to a segment of the active Evinos fault, located south of the lake. Calculation of the Coulomb stress induced by the combination of the 1975 Mw = 6.0 event and the three largest events of 10 April 2007 on the inferred structures, reveals that most of the seismicity lies within the "stress-loaded" region, except for the westernmost activity, which probably belongs to the deep part of the AFZ. A total of 178 reliable focal mechanisms were determined by regional and local body-wave modeling (5 largest events) and P-wave first motion polarity data. The types of the obtained focal mechanisms are predominantly normal and strike-slip, however, numerous earthquakes were found to exhibit reverse faulting. Inversion of focal mechanism data showed that the prevailing principal horizontal component σ3 is quite homogeneous throughout the activated area with a roughly NW-SE trend, parallel to the strike of the Hellenides. On the contrary, the compressional field σ1 appears in two patterns: NE-SW trending onshore and NW-SE trending beneath the lake. This apparent rotation of σ1 by 90° reveals a

  3. Preliminary Vertical Slip Rate for the West Tahoe Fault from six new Cosmogenic 10Be Exposure Ages of Late Pleistocene Glacial Moraines at Cascade Lake, Lake Tahoe, California

    NASA Astrophysics Data System (ADS)

    Pierce, I. K. D.; Wesnousky, S. G.; Kent, G. M.; Owen, L. A.

    2015-12-01

    The West Tahoe Fault is the primary range bounding fault of the Sierra Nevada at the latitude of Lake Tahoe. It is a N-NW striking, east dipping normal fault that has a pronounced onshore quaternary scarp extending from highway 50 southwest of Meyers, CA to Emerald Bay. At Cascade Lake, the fault cuts and progressively offsets late Pleistocene right lateral moraines. The fault vertically offsets the previously mapped Tahoe moraine ~83 m and the Tioga moraine ~23 m, measured from lidar data. Seventeen samples were collected for 10Be cosmogenic age analysis from boulders on both the hanging and footwalls of the fault along the crests of these moraines.We report here the initial analysis of 6 of these boulders and currently await processing of the remainder. The 10Be exposure ages of 3 boulders each on the younger Tioga and older Tahoe moraines range from 12.7 +/- 1.6 to 20.7 +/- 3.3 ka and 13.3 +/- 2.1 to 72.5 +/- 8.8 ka, respectively. Using the oldest ages as minima, these preliminary results suggest that the slip rate has averaged ~1 mm/yr since the penultimate glaciation, in accord with estimates of previous workers, and place additional bounds on the age of glaciation in the Lake Tahoe basin. The Last Glacial Maxima and penultimate glaciation near Lake Tahoe thus appear to coincide with the Tioga and Tahoe II glaciations of the Eastern Sierra.

  4. A multidisciplinary geomatics approach to morphometric and morphotectonic analysis of the Cannobino Basin (Piemonte Region, NW-Italy).

    NASA Astrophysics Data System (ADS)

    Bacenetti, Marco; Ghiraldi, Luca; Giardino, Marco

    2014-05-01

    The paper presents an integrated multidisciplinary approach to the morphometric and morphotectonic characterization of the Cannobino Basin (Piemonte Region, NW-Italy). The basin is drained by the Cannobino river; in its first 8 km, it flows SE to NW along a wide valley characterized by glacial landforms; thereafter it suddenly turns South assuming a W to E direction, by flowing in a deeply entrenched valley to the intermontane basin of the Maggiore Lake. This area belongs to the Lepontine Alps, which from the geological point of view belong to the Southern Alps. His Hercynian basement is divided in two units: Ivrea-Verbano Zone (IVZ) and Serie dei Laghi (SDL). The IVZ outcrops in the northern sector of the basin, while the SDL outcrops in the southern and central sector. They separated by the Cossato-Mergozzo-Brissago (CMB) and Pogallo lines (PL). These major discontinuities and the neoctonic activity of their shear zones possibly control Quaternary evolution of the alpine relief. Detailed studies of the area are needed for understanding possible interactions of neotectonic activity, fluvial/glacial erosional/depositional processes and slope dynamics. Our focus is on drainage basin characteristics and its evolutionary stages in response to local and regional base level changes and to differential rock uplift. GIS methodologies combined with DEMs analyses are among the most common geomatics approaches to geomorphology. Based on this framework, an evaluation of the geomorphometric characteristic of the Cannobino Basin has been carried out by using an aerial LIDAR DEM (5x5 meters, Regione Piemonte, 2009). The workflow followed for calculating the geomorphic indexes can be summarized in different steps: i) drainage network extraction and hierarchization; ii) lineament features digitalization and interpretation; iii) azimuthal distribution of drainage pattern; iv) DEM analysis and evaluation of linear, areal indexes and SWAT profile. The multidisciplinary and innovative

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

    PubMed

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

    2016-06-01

    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. PMID:27104923

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

    PubMed

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

    2016-06-01

    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.

  7. Active tectonics coupled to fluvial erosion in the NW Himalaya

    NASA Astrophysics Data System (ADS)

    Vannay, J.-C.; Grasemann, B.; Rahn, M.; Frank, W.; Carter, A.

    2003-04-01

    Both syntaxial extremities of the Himalaya show a spatial correlation between active exhumation of deep crustal rocks and the presence of powerful rivers, the Indus and the Tsangpo-Brahmaputra, cutting across the range two of the deepest gorges on Earth. These features strongly suggests that vigorous fluvial erosion can locally enhance isostatic and tectonic uplift, which in turn contributes to heat advection and weakening of the crust, as well as to maintain steep topographic gradients [Zeitler et al., 2001]. In order to test this positive feedback model, we combined structural and geochronological data to constrain the tectono-thermal evolution along the Sutlej (NW India), the third largest river cross-cutting entirely the Himalaya. The Himalayan crystalline core zone exposed along the Sutlej Valley is composed of two gneiss sheets, that were successively underthrusted and tectonically extruded as a consequence of the foreland-directed propagation of deformation in the Indian plate margin. During Early to Middle Miocene, combined thrusting along the Main Central Thrust (MCT) and extension along the Sangla Detachment induced the rapid exhumation and cooling of the amphibolite facies to migmatitic High Himalayan Crystalline Sequence [Vannay &Grasemann, 2001]. Underthrusting beneath the MCT led to the creation of the amphibolite facies Lesser Himalayan Crystalline Sequence (LHCS). The LHCS cooled rapidly from Late Miocene to Pleistocene, as a consequence of tectonic extrusion controlled by thrusting along the Munsiari Thrust, and extension in the MCT hanging wall. This phase is still active, as indicated by: (1) cooling rates in excess of 100^oC/Myr during the past ˜3 Myr in the LHCS; (2) Holocene neo-tectonic activity; (3) present-day hydrothermal activity testifying to elevated near-surface geothermal gradients; and (4) seismic activity along the Munsiari Thrust. Modelling of fluvial erosion in the Himalaya indicate that the Sutlej Valley corresponds to the main

  8. SAR measurements of coastal features in the NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Redondo, Jose M.; Martinez Benjamin, Juan Jose; Diez, Margarita; Lopez Gonzalez-Nieto, Pilar

    2013-04-01

    The Synthetic Aperture Radar (SAR) is a useful tool to study both marine water dynamics and its pollution, this is relevant near the coastline, where river pollution may be also important. Oil spills and natural slicks are detected with SAR [1-3] to reveal river and vessel pollution as well as the complex eddy and current interaction in the ocean surface near the coastline. In the framework of the ESA and European Union contracts, more than 1000 SAR images of the North-west Mediterranean Sea area taken between December 1996 and December 2008 are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, oil spills and tensioactive slicks that eventually allow predicting the behaviour of different tracers and pollutants in the NW Mediterranean Sea. Thanks to different polarization and intensity levels in satellite imagery can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar as a function of spill parameters, environmental conditions and history of both oil release and weather conditions. (Environmental factors determine [4] spreading, drift and weathering of oil on the sea surface - see: Behaviour oil at sea). Detecting the low contrast patches depends also on the speckle noise which always presents in the image. Application of different filters (available for example in several image processing software (Matlab, Envi, IDL) to the radar data decreases noise level and improves the feature detecting in the image [1] Bezerra, M.O., Diez, M., Medeiros, C., Rodriguez, A., Bahia, E., Sanchez-Arcilla, A. and Redondo, J.M. 1998. Study on the influence of waves on coastal diffusion using image analysis. Applied Scientific Research 59, pp.191-204. [2] Carrillo, A., A., Sanchez,, M

  9. An Operational Coastal Forecasting System in Galicia (NW Spain)

    NASA Astrophysics Data System (ADS)

    Balseiro, C. F.; Carracedo, P.; Pérez, E.; Pérez, V.; Taboada, J.; Venacio, A.; Vilasa, L.

    2009-09-01

    The Galician coast (NW Iberian Peninsula coast) and mainly the Rias Baixas (southern Galician rias) are one of the most productive ecosystems in the world, supporting a very active fishing and aquiculture industry. This high productivity lives together with a high human pressure and an intense maritime traffic, which means an important environmental risk. Besides that, Harmful Algae Blooms (HAB) are common in this area, producing important economical losses in aquiculture. In this context, the development of an Operational Hydrodynamic Ocean Forecast System is the first step to the development of a more sophisticated Ocean Integrated Decision Support Tool. A regional oceanographic forecasting system in the Galician Coast has been developed by MeteoGalicia (the Galician regional meteorological agency) inside ESEOO project to provide forecasts on currents, sea level, water temperature and salinity. This system is based on hydrodynamic model MOHID, forced with the operational meteorological model WRF, supported daily at MeteoGalicia . Two grid meshes are running nested at different scales, one of ~2km at the shelf scale and the other one with a resolution of 500 m at the rias scale. ESEOAT (Puertos del Estado) model provide salinity and temperature fields which are relaxed at all depth along the open boundary of the regional model (~6km). Temperature and salinity initial fields are also obtained from this application. Freshwater input from main rivers are included as forcing in MOHID model. Monthly mean discharge data from gauge station have been provided by Aguas de Galicia. Nowadays a coupling between an hydrological model (SWAT) and the hydrodynamic one are in development with the aim to verify the impact of the rivers discharges. The system runs operationally daily, providing two days of forecast. First model verifications had been performed against Puertos del Estado buoys and Xunta de Galicia buoys network along the Galician coast. High resolution model results

  10. Geochemistry and petrology of nephrite from Alamas, Xinjiang, NW China

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Deng, Jun; Shi, Guanghai; Yui, Tzen-Fu; Zhang, Guibin; Abuduwayiti, Maituohuti; Yang, Liqiang; Sun, Xiang

    2011-08-01

    The Hetian nephrite deposit is one of the largest nephrite deposits worldwide. Located within the Hetian deposit, Xinjiang, Northwest China, the Alamas ore body occurs as veins on the contact between the Late Variscan granodiorite and Precambrian dolomitic marble. Petrographic studies and electronic microprobe analyses reveal two possible nephrite formation processes: (1) dolomitic marble → tremolite and (2) dolomitic marble → diopside → tremolite. Nephrite veins show continuous coloration zones, ranging from white and white-green zones to a green zone towards the granodiorite, with increasing concentrations of Cr, FeO and TFe 2O 3. All these nephrite samples have quite low Cr and Ni contents (8.95-178.7 ppm and 0.05-3.95 ppm, respectively) relative to serpentinite-related nephrite (Cr 2O 3, 0.07-0.43 wt.%; NiO, 0.08-0.36 wt.%). Their bulk-rock REE patterns exhibit strong negative Eu anomalies (0.03-0.21) with declined LREE, flat HREE and low ΣREE concentration (2.84-84.81 ppm), similar to those of host dolomitic marble samples with negative Eu anomalies (0.15-0.23), declined LREE, flat HREE and lower ΣREE concentration (8.48-11.1 ppm), indicating a close genetic relationship between them. Homogenization temperatures analyses on the fluid inclusions in tremolite yield a minimum temperature 293 °C for the nephrite formation. Nephrites have oxygen and hydrogen isotope compositions in the range from +3.2 to +6.2 per mil and -83.0 to -94.7 per mil, respectively. The corresponding equilibrated fluids have isotope compositions of δ 18O = +3.1 to +6.1 (293 °C). Combined with field observation, there are at least three possible fluid sources: meteoric water, magmatic water and CO 2 derived from decarbonation of dolomite, and a metasomatic and dolomite-related origin is suggested for the Alamas ore body in the Hetian nephrite deposit, Xinjiang, NW China.

  11. Sanctuaries for lake trout in the Great Lakes

    USGS Publications Warehouse

    Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

    1987-01-01

    Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

  12. Lake v. Arnold.

    PubMed

    2000-01-01

    Court Decision: 232 Federal Reporter, 3d Series 360, 2000 Nov 7 (date of decision). The U.S. Court of Appeals for the Third Circuit agreed with the lower court that the husband of a mentally disabled woman who was involuntarily sterilized by her parents at age 16 was not entitled to a loss of consortium claim because the injury occurred before the couple was married, both he and his wife were aware of the injury before they married and there was not subsequent harm from the initial injury (sterilization) after the Lakes' marriage. At age 16, Lake, a mentally disabled woman, was taken to a hospital by her father and stepmother and was permanently sterilized. The claim by Lake and her husband against her parents, hospital, and physicians that her civil rights were violated because the sterilization was nonconsensual was dismissed by the court on statute of limitation grounds.

  13. Viruses in Antarctic lakes

    NASA Technical Reports Server (NTRS)

    Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

    1998-01-01

    Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

  14. Michigan: The Great Lakes State

    ERIC Educational Resources Information Center

    McKay, Sandra Lee; La Luzerne-Oi, Sally

    2009-01-01

    Although Michigan is often called the "Wolverine State," its more common nickname is the "Great Lakes State." This name comes from the fact that Michigan is the only state in the United States that borders four of the five Great Lakes. Also referred to as the "Water Wonderland," Michigan has 11,000 additional lakes, 36,000 miles of streams, and…

  15. The Great Lakes whitefish

    USGS Publications Warehouse

    Van Oosten, John; Elliot, Charles

    1942-01-01

    In every one of the Great Lakes- Ontario, Erie, Huron, Michigan, and Superior- the most valuable fishes are declining, and there is no evidence that this trend will be reversed. Under existing conditions of a diversity of regulations that vary between states and between the two countries, and with the present methods of fishing, the Great Lakes fisheries are doomed. This chapter deals with the common whitefish, a valuable species which many believe to be the next that will go unless positive action is forthcoming soon.

  16. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  17. Use of Geoenvironmental Impact of Climate Change in Management and Assessment Lake Nasser, Egypt

    NASA Astrophysics Data System (ADS)

    Sayed El Gammal, El

    2010-05-01

    This study monitor how to management the water stored after High Dam in the biggest artificial global lake (Lake Nasser), Integration of physical features and water level changes within the lake curse and margins. Statistical data presented, interpreted and correlated with using remote sensing technique in change detection. Different Landsat images acquired at different times (1970, 1982, 1987, 2000, 2003 and 2008) have been used by the ERDAS and ARC-GIS techniques to estimate the movements of lake borders and water fluctuation proportional to water sizes in place. Regards to water fluctuation degree, the lake can be divide into 4 classes in lake's sectors: 1, show maximum change degree, 2 show medium change degree, 3 slight to neglected change degree, and 4, no change. Functions control the water fluctuation in Lake Nasser are; (i) the granite and Nubia sandstone outcrops, (ii) NW, E-W and NE structure in order, (iii) low topography. Water level change detection on Landsat images in different dates elucidates big variation between different lake sectors, there are strangle points and other useful localities that yields environmental implication. The strangle points detected in the curse of River Nile and after 40 years since lake initiation, the water are more strangled in this curse because of the water velocity before the High Dam was high speed can pass toward the north in Nile annual flood but after the dam, the water velocity decreased. Due to decrease of velocity, the water go to narrow incised wadis (Khors) in the Nile high flood plus the sands drift, these khors are bounded by hard Nubia sandstone already saturated by water and it consider the main underground water reservoir in Egypt. In addition, the entrance of the lake in Halfa inside Sudan is subjected to suspended sediments (mud) forming new delta plus the sands drift that impair the reservoir in Egypt. Wadi Allaqui have 250 km length and 2 km average width, it's is the 5th order channel inside a

  18. Reevaluation of lake trout and lake whitefish bioenergetics models

    USGS Publications Warehouse

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  19. Fish Lake, Utah - a promising long core site straddling the Great Basin to Colorado Plateau transition zone

    NASA Astrophysics Data System (ADS)

    Marchetti, D. W.; Abbott, M. B.; Bailey, C.; Wenrich, E.; Stoner, J. S.; Larsen, D. J.; Finkenbinder, M. S.; Anderson, L.; Brunelle, A.; Carter, V.; Power, M. J.; Hatfield, R. G.; Reilly, B.; Harris, M. S.; Grimm, E. C.; Donovan, J.

    2015-12-01

    Fish Lake (~7x1.5 km and 2696 m asl) is located on the Fish Lake Plateau in central Utah. The Lake occupies a NE-striking tectonic graben; one of a suite of grabens on the Plateau that cut 21-26 Ma volcanic rocks. The lake outflows via Lake Creek to the NE where it joins Sevenmile Creek to become the Fremont River, a tributary to the Colorado River. A bathymetric survey reveals a mean depth of 27 m and a max depth of 37.2 m. The lake bottom slopes from NW to SE with the deepest part near the SE wall, matching the topographic expression of the graben. Nearby Fish Lake Hightop (3545 m) was glaciated with an ice field and outlet glaciers. Exposure ages indicate moraine deposition during Pinedale (15-23 ka) and Bull Lake (130-150 ka) times. One outlet glacier at Pelican Canyon deposited moraines and outwash into the lake but the main basin of the lake was never glaciated. Gravity measurements indicate that lake sediments thicken toward the SE side of the lake and the thickest sediment package is modeled to be between 210 and 240 m. In Feb 2014 we collected cores from Fish Lake using a 9-cm diameter UWITECH coring system in 30.5 m of water. A composite 11.2-m-long core was constructed from overlapping 2 m drives that were taken in triplicate to ensure total recovery and good preservation. Twelve 14C ages and 3 tephra layers of known age define the age model. The oldest 14C age of 32.3±4.2 cal ka BP was taken from 10.6 m. Core lithology, CT scans, and magnetic susceptibility (ms) reveal three sediment packages: an organic-rich, low ms Holocene to post-glacial section, a fine-grained, minerogenic glacial section with high ms, and a short section of inferred pre-LGM sediment with intermediate composition. Extrapolating the age model to the maximum estimated sediment thicknesses suggest sediments may be older than 500-700 ka. Thus Fish Lake is an ideal candidate for long core retrieval as it likely contains paleoclimatic records extending over multiple glacial cycles.

  20. Gas exchange on Mono Lake and Crowley Lake, California

    NASA Technical Reports Server (NTRS)

    Wanninkhof, Rik; Ledwell, James R.; Broecker, Wallace S.

    1987-01-01

    Gas exchange coefficients (k) have been determined for freshwater Crowley Lake and saline Mono Lake through the use of a man-made purposefully injected gas, SF6. The concentration decreased from an initial value of 40 to 4 pmol/L for Mono Lake and from 20 to 1 pmol/L for Crowley lake over a period of 6 wks. Wind-speed (u) records from anemometers on the shore of each lake made it possible to determine the relationship between k and u. The average u and k values for the experiment were identical for the two lakes, despite the large chemical differences. It is estimated that, for the u values observed over Mono Lake from July to December 1984, the exchange of CO2 occurred 2.5 times faster than without chemical enhancement. This is a factor of 4 lower than needed to explain the high invasion rate of C-14 produced by nuclear bomb tests.

  1. The 2000/60/EC Water Framework Directive and the Flooding of the Brown Coal Meirama Open Pit (NW Spain)

    NASA Astrophysics Data System (ADS)

    Delgado, J.; Juncosa, R.

    2009-04-01

    Coal mining in Galicia (NW Spain) has been an important activity which came to an end in December, 2007. Hence, for different reasons, the two large brown coal mines in Galicia (the As Pontes mine, run by ENDESA GENERACIÓN, and the Meirama mine, owned by Lignitos de Meirama, S.A., LIMEISA), have started closure procedures, both of which are considering the flooding of the mine pits to create two large lakes (~8 km2 in As Pontes and ~2 km2 in Meirama). They will be unique in Galicia, a nearly lake-free territory. An important point to consider as regards the flooding of the lignite mine pits in Galicia is how the process of the creation of a body of artificial water will adapt to the strict legal demands put forth in the Water Framework Directive. This problem has been carefully examined by different authors in other countries and it raises the question of the need to adapt sampling surveys to monitor a number of key parameters -priority substances, physical and chemical parameters, biological indicators, etc.- that cannot be overlooked. Flooding, in both cases consider the preferential entrance into the mine holes of river-diverted surface waters, in detriment of ground waters in order to minimize acidic inputs. Although both mines are located in the same hydraulic demarcation (i.e. administrative units that, in Spain, are in charge of the public administration and the enforcement of natural water-related laws) the problems facing the corresponding mine managers are different. In the case of Meirama, the mine hole covers the upper third part of the Barcés river catchment, which is a major source of water for the Cecebre reservoir. That reservoir constitutes the only supply of drinking water for the city of A Coruña (~250.000 inhabitants) and its surrounding towns. In this contribution we will discuss how mine managers and the administration have addressed the uncertainties derived from the implementation of the Water Framework Directive in the particular case of

  2. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    USGS Publications Warehouse

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  3. Temperature Trends in Montane Lakes

    NASA Astrophysics Data System (ADS)

    Melack, J. M.; Sadro, S.; Jellison, R.

    2014-12-01

    Long-term temperature trends in lakes integrate hydrological and meteorological factors. We examine temperature trends in a small montane lake with prolonged ice-cover and large seasonal snowfall and in a large saline lake. Emerald Lake, located in the Sierra Nevada (California), is representative of high-elevation lakes throughout the region. No significant trend in outflow temperature was apparent from 1991to 2012. Snowfall in the watershed accounted for 93% of the variability in average summer lake temperatures. Mono Lake (California) lies in a closed, montane basin and is hypersaline and monomictic or meromictic. Temperature profiles have been collected from 1982 to 2010. In the upper water column, the July-August-September water temperatures increased 0.8-1.0°C over the 29 years. This rate of warming is less than published estimates based on satellite-derived skin temperatures and will discussed in the context of general limnological interpretation of temperature trends.

  4. Lake Michigan: Nearshore Variability

    EPA Science Inventory

    We conducted a high-resolution survey in the nearshore of Lake Michigan at a 20 meter contour using towed electronic instrumentation. The nearly 1200 km survey was conducted Sep 8-15, 2010. We also conducted six cross-contour tows. Along the survey tracks we sampled fixed stat...

  5. Lake Ontario: Nearshore Variability

    EPA Science Inventory

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  6. The People's Lake

    ERIC Educational Resources Information Center

    Carlson, Karen Townsend

    1975-01-01

    Citizen action to stop the disposal of taconite tailings into Lake Superior was unsuccessful when the courts settled in the favor of industry. Although citizen research revealed a form of asbestos, as well as other toxic chemicals in the discharged wastes, company representatives stated that there were no health hazards. (MA)

  7. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Chicago, IL. Great Lakes National Program Office.

    This booklet introduces an environmental curriculum for use in a variety of elementary subjects. The lesson plans provide an integrated approach to incorporating Great Lakes environmental issues into the subjects of history, social studies, and environmental sciences. Each of these sections contains background information, discussion points, and a…

  8. Temperate Lakes Discovered on Titan

    NASA Astrophysics Data System (ADS)

    Vixie, Graham; Barnes, Jason W.; Jackson, Brian; Wilson, Paul

    2012-04-01

    We have discovered two temperate lakes on Titan using Cassini's Visual and Infrared Mapping Spectrometer (VIMS). Three key features help to identify these surface features as lakes: morphology, albedo, and specular reflection. The presence of lakes at the mid-latitudes mean liquid can accumulate and remain stable outside of the poles. We first identify a lake surface by looking for possible shorelines with a lacustrine morphology. Then, we apply a simple atmospheric correction that produces an approximate surface albedo. Next, we prepare cylindrical projection maps of the brightness of the sky as seen from any points on the surface to identify specular reflections. Our techniques can then be applied to other areas, such as Arrakis Planitia, to test for liquid. Currently, all the known lakes on Titan are concentrated at the poles. Lakes have been suggested in the tropic zone by Griffith et al. Our discovery of non-transient, temperate lakes has important implications for Titan's hydrologic cycle. Clouds have been recorded accumulating in the mid-latitudes and areas have been darkened by rainfall but later brightened after evaporation (Turtle et al. 2011). Stable temperate lakes would affect total rainfall, liquid accumulation, evaporation rates, and infiltration. Polaznik Macula (Figure 1) is a great candidate for lake filling, evaporation rates, and stability. References: Griffith, C., et al.: "Evidence for Lakes on Titan's Tropical Surface". AAS/Division for Planetary Sciences Meeting Abstracts #42, Vol. 42, pp. 1077, 2010. Turtle, E. P., et al.: "Rapid and Extensive Surface Changes Near Titan's Equator: Evidence of April Showers". Science, Vol. 331, pp. 1414-, 2011. Figure 1: Polaznik Macula is the large, dark area central to the figure. The encircled dark blue areas represent positively identified lake regions in the T66 flyby. The light blue areas represent lake candidates still under analysis. The green circle marks a non-lake surface feature enclosed by a

  9. Reducing the contact resistance of SiNW devices by employing a heavily doped carrier injection layer.

    PubMed

    Liu, Donghua; Shi, Zhiwen; Zhang, Lianchang; He, Congli; Zhang, Jing; Cheng, Meng; Yang, Rong; Tian, Xuezeng; Bai, Xuedong; Shi, Dongxia; Zhang, Guangyu

    2012-08-01

    Silicon nanowires (SiNWs) are promising building blocks for future electronic devices. In SiNW-based devices, reducing the contact resistance of SiNW-metal as much as possible is critically important. Here we report a simple fabrication approach for SiNW field effect transistors (FETs) with low contact resistances by employing a heavily doped carrier injection layer wrapped around SiNWs at the contact region. Both n- and p-type SiNW-FET devices with carrier injection layers were investigated, the contact resistances were one order smaller than those without carrier injection layers and only contribute less than 14.8% for n-type devices and 11.4% for p-type devices, respectively, to the total resistance. Such low contact resistance guarantees the device characteristics mainly from the channel region of SiNW-based devices.

  10. Lake trout rehabilitation in Lake Erie: a case history

    USGS Publications Warehouse

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  11. Movements of hatchery-reared lake trout in Lake Superior

    USGS Publications Warehouse

    Pycha, Richard L.; Dryer, William R.; King, George R.

    1965-01-01

    The history of stocking of lake trout (Salvelinus namaycush) in the Great Lakes is reviewed. The study of movements is based on capture of 24,275 fin-clipped lake trout taken in experimental gill nets and trawls and commercial gill nets. Yearling lake trout planted from shore dispersed to 15-fath (27-m) depths in 3A? hr. Most fish remained within 2 miles (3.2 km) of the planting site 2 months, but within 4 months some fish had moved as much as 17 miles (27 km). The highest abundance of planted lake trout was in areas 2-4 miles (3.2-6.4 km) from the planting site even 3 years after release. Distance moved and size of fish were not correlated. Dispersal of lake trout begins at planting and probably continues until the fish are mature. Most movement was eastward in southern Lake Superior and followed the counterclockwise surface currents. Movement is most rapid in areas of strong currents and slowest in areas of weak currents or eddies. Movement to areas west of the Keweenaw Peninsula was insignificant from plantings in Keweenaw Bay and nil from other plantings farther east. Lake trout planted in the eastern third of the lake dispersed more randomly than those planted farther west. Few fish moved farther offshore than the 50-fath (91-m) contour. Lake trout planted in Canadian waters made insignificant contributions to populations in US waters.

  12. Microbiology of Lonar Lake and other soda lakes.

    PubMed

    Antony, Chakkiath Paul; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-03-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence.

  13. Microbiology of Lonar Lake and other soda lakes.

    PubMed

    Antony, Chakkiath Paul; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-03-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

  14. Flexible transparent conducting composite films using a monolithically embedded AgNW electrode with robust performance stability

    NASA Astrophysics Data System (ADS)

    Im, Hyeon-Gyun; Jin, Jungho; Ko, Ji-Hoon; Lee, Jaemin; Lee, Jung-Yong; Bae, Byeong-Soo

    2013-12-01

    We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices.We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices. Electronic supplementary information (ESI) available: Further characteristics of AgNW-GFRHybrimer films and thermal oxidation of AgNW on glass. See DOI: 10.1039/c3nr05348b

  15. Potential strategies for recovery of lake whitefish and lake herring stocks in eastern Lake Erie

    USGS Publications Warehouse

    Oldenburg, K.; Stapanian, M.A.; Ryan, P.A.; Holm, E.

    2007-01-01

    Lake Erie sustained large populations of ciscoes (Salmonidae: Coregoninae) 120 years ago. By the end of the 19th century, abundance of lake whitefish (Coregonus clupeaformis) had declined drastically. By 1925, the lake herring (a cisco) population (Coregonus artedii) had collapsed, although a limited lake herring fishery persisted in the eastern basin until the 1950s. In the latter part of the 20th century, the composition of the fish community changed as oligotrophication proceeded. Since 1984, a limited recovery of lake whitefish has occurred, however no recovery was evident for lake herring. Current ecological conditions in Lake Erie probably will not inhibit recovery of the coregonine species. Recovery of walleye (Sander vitreus) and efforts to rehabilitate the native lake trout (Salvelinus namaycush) in Lake Erie will probably assist recovery because these piscivores reduce populations of alewife (Alosa psuedoharengus) and rainbow smelt (Osmerus mordax), which inhibit reproductive success of coregonines. Although there are considerable spawning substrates available to coregonine species in eastern Lake Erie, eggs and fry would probably be displaced by storm surge from most shoals. Site selection for stocking or seeding of eggs should consider the reproductive life cycle of the stocked fish and suitable protection from storm events. Two potential sites in the eastern basin have been identified. Recommended management procedures, including commercial fisheries, are suggested to assist in recovery. Stocking in the eastern basin of Lake Erie is recommended for both species, as conditions are adequate and the native spawning population in the eastern basin is low. For lake herring, consideration should be given to match ecophenotypes as much as possible. Egg seeding is recommended. Egg seeding of lake whitefish should be considered initially, with fingerling or yearling stocking suggested if unsuccessful. Spawning stocks of whitefish in the western basin of Lake

  16. Lake Mead--clear and vital

    USGS Publications Warehouse

    Wessells, Stephen M.; Rosen, Michael

    2013-01-01

    Lake Mead – Clear and Vital” is a 13 minute documentary relating the crucial role of science in maintaining high water quality in Lake Mead. The program was produced coincident with release of the Lakes Mead and Mohave Circular a USGS publication covering past and on-going research in the lakes and tributaries of the Lake Mead National Recreation Area.

  17. Predicting Maximum Lake Depth from Surrounding Topography

    EPA Science Inventory

    Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

  18. Lake Erie...Take a Bow.

    ERIC Educational Resources Information Center

    Canning, Maureen; Dunlevy, Margie

    This elementary school teaching unit was developed as a part of a series of teaching units that deal with Lake Erie. This unit was developed to enable children to: (1) identify the Great Lakes and pick out Lake Erie on a map; (2) demonstrate knowledge of Lake Erie's origin and geography; (3) list some uses of Lake Erie; and (4) give examples of…

  19. 13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. RAILROAD BRIDGE MISSISSIPPI, MONROE CO., ABERDEEN 1.5 mi. NW of Amory. St. Louis and San Francisco RR bridge. Steam locomotive and coal train cross bridge on 10 August 1921. Credit: Owned by Jack Donnell, Columbus, Ms., photographer. Copied by Sarcone Photography, Columbus, Ms. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

  20. Mineralogical Characteristics of Specimens of a Pseudometeorite ``Fall'' from NW Iran

    NASA Astrophysics Data System (ADS)

    Pourkhorsandi, H.; Mirnejad, H.

    2014-09-01

    In the early hours of October 22, 2011, people of Khameneh town in NW of Iran, noticed sounds of some colliding objects to home roofs and yard floors. Mineralogical investigations revealed the terrestrial and man-made origin of these stony objects.

  1. Neodymium isotope evolution of NW Tethyan upper ocean waters throughout the Cretaceous

    NASA Astrophysics Data System (ADS)

    Pucéat, Emmanuelle; Lécuyer, Christophe; Reisberg, Laurie

    2005-08-01

    Neodymium isotope compositions of twenty-four fish teeth, nineteen from the NW Tethys and five from different locations within the Tethys, are interpreted to reflect the evolution of Tethyan upper ocean water composition during the Cretaceous and used to track changes in erosional inputs to the NW Tethys and in oceanic circulation throughout the Cretaceous. The rather high ɛNd (up to - 7.6) of the NW Tethyan upper ocean waters recorded from the Late Berriasian to the Early Aptian and the absence of negative excursions during this interval support the presence of a permanent westward flowing Tethys Circumglobal Current (TCC). This implies that temperature variations during this time period, inferred from the oxygen isotope analysis of fish tooth enamel, were not driven by changes in surface oceanic currents, but rather by global climatic changes. The results presented here represent a significant advance over previously published Cretaceous seawater Nd isotope records. Our newly acquired data now allow the identification of two stages of low ɛNd values in the NW Tethys, during the Early Albian-Middle Albian interval (down to - 10) and the Santonian-Early Campanian (down to - 11.4), which alternate with two stages of higher ɛNd values (up to - 9) during the Late Albian-Turonian interval and the Maastrichtian. Used in conjunction with the oxygen isotope record, the fluctuations of ɛNd values can be related to major climatic, oceanographic, and tectonic events that appeared in the western Tethyan domain.

  2. 23. Building N9; 3/4 view, looking NW at loading dock. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Building N-9; 3/4 view, looking NW at loading dock. The view also shows the relationship of the blast barricades to the building. (Ryan) - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  3. 4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. DETAIL VIEW OF NW CORNER OF BUILDING 1'S W WING, SHOWING THE PILASTERS, TERRA COTTA PANELS, AND THE EGYPTIAN MOTIF DECORATIVE CORNICE ELEMENTS; LOOKING ENE. (Harms) - Veterans Administration Medical Center, Building No. 1, Old State Route 13 West, Marion, Williamson County, IL

  4. Airborne radioactivity Survey of part of Saratoga NW quadrangle, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 133 square miles of Saratoga NW quadrangle, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  5. Fecundity of hatchery lake trout in Lake Ontario

    USGS Publications Warehouse

    Fitzsimons, John D.; O'Gorman, Robert

    1996-01-01

    Fecundity (egg number) was determined from 26 stocked (617-800 mm, total length) lake trout (Salvelinus namaycush) collected in western Lake Ontario during September 1992. Previous to this study, fecundity was evaluated only once in Lake Ontario using native stocks in 1927. The following relationships between fecundity and total length (TL) and weight (W) were obtained. Fecundity = -12,492 + 25.87 TL(mm) and Fecundity = -1,010 + 1,307 W(kg). Relative fecundity (number of eggs per kg of body weight) was unrelated to body weight and averaged 1,592 eggs kg-1. Fecundity of contemporary lake trout based on length was significantly lower than that of historic native stocks, but was similar to contemporary stocked lake trout in Lake Superior.

  6. Lake-wide distribution of Dreissena in Lake Michigan, 1999

    USGS Publications Warehouse

    Fleischer, Guy W.; DeSorcie, Timothy J.; Holuszko, Jeffrey D.

    2001-01-01

    The Great Lakes Science Center has conducted lake-wide bottom trawl surveys of the fish community in Lake Michigan each fall since 1973. These systematic surveys are performed at depths of 9 to 110 m at each of seven index sites around Lake Michigan. Zebra mussel (Dreissena polymorpha) populations have expanded to all survey locations and at a level to sufficiently contribute to the bottom trawl catches. The quagga (Dreissena bugensis), recently reported in Lake Michigan, was likely in the catches though not recognized. Dreissena spp. biomass ranged from about 0.6 to 15 kg/ha at the various sites in 1999. Dreissenid mussels were found at depths of 9 to 82 m, with their peak biomass at 27 to 46 m. The colonization of these exotic mussels has ecological implications as well as potential ramifications on the ability to sample fish consistently and effectively with bottom trawls in Lake Michigan.

  7. Lake Garda, Italy

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This ASTER image was acquired on July 29, 2000 and covers an area of 30 by 57 km in northern Italy. Lake Garda was formed by glaciers during the last Ice Age, and is Italy's largest lake. Lago di Garda lies in the provinces of Verona, Brescia, and Trento, and is 51 kilometers (32 miles) long and from 3 to 18 kilometers (2 to 11 miles) wide. The Sarca is its chief affluent, and the lake is drained southward by the Mincio, which discharges into the Po River. Many villas are situated on its shores. On the peninsula of Sirmione, at the southern end of the lake, are the ruins of a Roman villa and a castle of the Scaligers, an Italian family of the 16th century. The RIGHT image has the land area masked out, and a harsh stretch was applied to the lake values to display variations in sediment load. Also visible are hundreds of boats and their wakes, criss-crossing the lake.

    The image is centered at 45.6 degrees north latitude, 10.6 degrees east longitude.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for

  8. State of Michigan, Lake Michigan and Lake Huron, USA

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Almost the entire state of Michigan and most of lakes Michigan and Huron (45.5N, 83.5W) can be seen in this single midwinter view of the Great Lakes region. Even under midwinter snow and ice conditions, the distinctive silhouette of the state of Michigan is still easy to recognize as well as Lakes Michigan and Huron. The Canadian province of Ontario is at the top of the scene on the opposite shore from Michigan.

  9. Genetic diversity of Diporeia in the Great Lakes: comparison of Lake Superior to the other Great Lakes

    EPA Science Inventory

    Abundances of Diporeia have dropped drastically in the Great Lakes, except in Lake Superior, where data suggest that population counts actually have risen. Various ecological, environmental, or geographic hypotheses have been proposed to explain the greater abundance of Lake Supe...

  10. Aeolian sand preserved in Silver Lake: a new signal of Holocene high stands of Lake Michigan

    USGS Publications Warehouse

    Fisher, Timothy G.; Loope, Walter L.

    2005-01-01

    Aeolian sand within lake sediment from Silver Lake, Michigan can be used as a proxy for the timing of high lake levels of Lake Michigan.We demonstrate that the sand record from Silver Lake plotted as percent weight is in-phase with the elevation curve of Lake Michigan since the mid-Holocene Nipissing Phase. Because fluctuations in Lake Michigan's lake level are recorded in beach ridges, and are a response to climate change, the aeolian sand record within Silver Lake is also a proxy for climate change. It appears that increases in dune activity and lake sand are controlled by similar climatic shifts that drive fluctuations in lake level of Lake Michigan. High lake levels destabilize coastal bluffs that drive dune sand instability, and along with greater wintertime storminess, increase niveo-aeolian transport of sand across lake ice. The sand is introduced into the lake each spring as the ice cover melts.

  11. Life history of lake herring in Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; Beil, Joseph

    1964-01-01

    The average annual commercial catch of lake herring (Coregonus artedi) in U.S. waters of Lake Superior was nearly 12 million pounds in 1929-61. This production contributed 62.4 percent of the total U.S. take of lake herring for the Great Lakes. About 90 percent of the annual catch is taken from small-mesh gill nets during the November-December spawning season. The life-history studies were based on 12,187 fish collected in 1950-62; past growth was computed for 3,779 specimens collected from commercial landings at: Duluth, Minn.; Bayfield, Wis.; and Portage Entry and Marquette, Mich.

  12. Evidence of spring spawning lake trout in Lake Superior

    USGS Publications Warehouse

    Bronte, Charles R.

    1993-01-01

    In 1992, the U. S. Fish and Wildlife Service began research on the life history, population dynamics, and stock delineation of siscowet lake trout Salvelinus namaycush siscowet in Lake Superior. Siscowet were captured with gill nets in 80-150 m of water on 23-26 April 1992 north of the Apostle Islands in western Lake Superior. Of 91 captured siscowets, one male had fully developed testes in nearly ripe condition and one female had eggs running from the vent. This observation represents the earliest dates that lake trout of any morphotype have been found in spawning or near-spawning condition.

  13. Hydrology of Lake County, Florida

    USGS Publications Warehouse

    Knochenmus, Darwin D.; Hughes, G.H.

    1976-01-01

    Lake County includes a 1,150 square-mile area consisting of ridges, uplands, and valleys in central-peninsular Florida. About 32 percent of the county is covered by lakes, swamps, and marshes. Water requirements in 1970 averaged about 54 million gallons per day. About 85 percent of the water was obtained from wells; about 15 percent from lakes. The Floridan aquifer supplies almost all the ground water used in Lake County. Annual recharge to the Floridan aquifer averages about 7 inches over the county; runoff average 8.5 inches. The quality of ground and surface water in Lake County is in general good enough for most uses; however, the poor quality of Floridan-aquifer water in the St. John River Valley probably results from the upward movement of saline water along a fault zone. Surface water in Lake County is usually less mineralized than ground water but is more turbid and colored. (Woodard-USGS)

  14. Archaea in Yellowstone Lake.

    PubMed

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E; Inskeep, William P; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R; Nealson, Kenneth

    2011-11-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (~51,000 pyrosequencing reads; V1 and V2 regions) and Sanger sequencing of 200 near-full-length polymerase chain reaction (PCR) clones. Automated classifiers (Ribosomal Database Project (RDP) and Greengenes) were problematic for the 454-FLX reads (wrong domain or phylum), although BLAST analysis of the 454-FLX reads against the phylogenetically placed full-length Sanger sequenced PCR clones proved reliable. Most of the archaeal diversity was associated with vents, and as expected there were differences between the vents and the near-surface photic zone samples. Thaumarchaeota dominated all samples: vent-associated organisms corresponded to the largely uncharacterized Marine Group I, and in surface waters, ~69-84% of the 454-FLX reads matched archaeal clones representing organisms that are Nitrosopumilus maritimus-like (96-97% identity). Importance of the lake nitrogen cycling was also suggested by >5% of the alkaline vent phylotypes being closely related to the nitrifier Candidatus Nitrosocaldus yellowstonii. The Euryarchaeota were primarily related to the uncharacterized environmental clones that make up the Deep Sea Euryarchaeal Group or Deep Sea Hydrothermal Vent Group-6. The phylogenetic parallels of Yellowstone Lake archaea to marine microorganisms provide opportunities to examine interesting evolutionary tracks between freshwater and marine lineages.

  15. Great Lakes Energy Institute

    SciTech Connect

    Alexander, J. Iwan

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  16. Method for lake restoration

    DOEpatents

    Dawson, Gaynor W.; Mercer, Basil W.

    1979-01-01

    A process for removing pollutants or minerals from lake, river or ocean sediments or from mine tailings is disclosed. Magnetically attractable collection units containing an ion exchange or sorbent media with an affinity for a chosen target substance are distributed in the sediments or tailings. After a period of time has passed sufficient for the particles to bind up the target substances, a magnet drawn through the sediments or across the tailings retrieves the units along with the target substance.

  17. Not so Great Lakes?

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, “September of My Years” “Early Bird,” the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  18. Not so Great Lakes?

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, "September of My Years;" "Early Bird," the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  19. Angora Fire, Lake Tahoe

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  20. THOUSAND LAKES WILDERNESS, CALIFORNIA.

    USGS Publications Warehouse

    Till, Alison B.; McHugh, Edward L.

    1984-01-01

    A mineral survey of the Thousand Lakes Wilderness in northern California indicated little promise for the occurrence of mineral resources. Volcanic stone and cinders occur, but similar materials are found in abundance outside the wilderness. The wilderness is in the Cascade Volcanic Province, a setting locally favorable for geothermal resource potential. No geothermal potential was identified in the wilderness; subsurface potential cannot be evaluated without regional studies and drilling.

  1. Photochemical production of organic matter triplet states in water samples from mountain lakes, located below or above the tree line.

    PubMed

    De Laurentiis, Elisa; Minella, Marco; Maurino, Valter; Minero, Claudio; Brigante, Marcello; Mailhot, Gilles; Vione, Davide

    2012-08-01

    The production of triplet states (T(*)) of chromophoric dissolved organic matter (CDOM), reacting with the probe molecule 2,4,6-trimethylphenol (TMP) was measured upon irradiation of water samples, taken from lakes located in a mountain area (NW Italy) between 1450 and 2750 m above sea level. The lakes are located below or above the tree line and surrounded by different vegetation types (trees, alpine meadows or exposed rocks). The most photoactive samples belonged to lakes below the tree line and their fluorescence spectra and CDOM optical features suggested the presence of a relatively elevated amount of humic (allochthonous) material. The lowest (negligible) photoactivity was found for a lake surrounded by exposed rocks. Its CDOM showed an important autochthonous contribution (due to in-lake productivity) and considerably higher spectral slope compared to the other samples, suggesting low CDOM molecular weight and/or aromaticity. Among the samples, CDOM photoactivity (measured as the rate of TMP-reactive T(*) photoproduction) decreased with changing vegetation type in the order: trees, meadows, rocks. It could be connected with decreasing contribution from catchment runoff and increasing contribution from autochthonous processes and possibly precipitation.

  2. Landsat analysis of lake quality

    NASA Technical Reports Server (NTRS)

    Scarpace, F. L.; Fisher, L. T.; Holmquist, K. W.

    1979-01-01

    The trophic status of a number of inland lakes in Wisconsin has been assessed. The feasibility of using both photographic and digital representations of Landsat imagery was investigated during the lake classification project. The result of the investigation has been a semi-automatic data acquisition and handling system which, in conjunction with an analytical categorization scheme, can be used to classify all the significant lakes in the state.

  3. Crater Lake: blue through time

    USGS Publications Warehouse

    Larson, Gary L.; Buktenica, Mark; Collier, Robert

    2003-01-01

    Blue is the color of constancy, hence the term true blue. The unearthly blueness of Crater Lake reflects its pristine character and gives scientists a focal point for studying human impacts on aquatic environments over long periods of time. Scientists with the U.S. Geological Survey (USGS), National Park Service, and Oregon State University have systematically studied the lake for the last two decades. Long-term monitoring of this lake is a priority of Crater Lake National Park and will continue far into the future.

  4. Great Lakes' regional climate regimes

    NASA Astrophysics Data System (ADS)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  5. Glacioisostasy and Lake-Level Change at Moosehead Lake, Maine

    USGS Publications Warehouse

    Balco, G.; Belknap, D.F.; Kelley, J.T.

    1998-01-01

    Reconstructions of glacioisostatic rebound based on relative sea level in Maine and adjacent Canada do not agree well with existing geophysical models. In order to understand these discrepancies better, we investigated the lake-level history of 40-km-long Moosehead Lake in northwestern Maine. Glacioisostasy has affected the level of Moosehead Lake since deglaciation ca. 12,500 14C yr B.P. Lowstand features at the southeastern end and an abandoned outlet at the northwestern end of the lake indicate that the lake basin was tilted down to the northwest, toward the retreating ice sheet, by 0.7 m/km at 10,000 14C yr B.P. Water level then rose rapidly in the southeastern end of the lake, and the northwestern outlet was abandoned, indicating rapid relaxation of landscape tilt. Lowstand features at the northwestern end of the lake suggest that the lake basin was tilted to the southeast at ca. 8750 14C yr B.P., possibly as the result of a migrating isostatic forebulge. After 8000 14C yr B.P., water level at the southeastern end was again below present lake level and rose gradually thereafter. We found no evidence suggesting that postglacial climate change significantly affected lake level. The rebound history inferred from lake-level data is consistent with previous interpretations of nearby relative sealevel data, which indicate a significantly steeper and faster-moving ice-proximal depression and ice-distal forebulge than geophysical models predict. ?? 1998 University of Washington.

  6. Active and Fossil Geothermal Activity at Lake Chapala, Mexico

    NASA Astrophysics Data System (ADS)

    Zârate-del Vall, P.

    2002-12-01

    Geothermal systems are very abundant in the tectonically active zones of the earth's crust and the Citala rift, where Lake Chapala is located, is not the exception. The Lake Chapala basin is characterized by its paleo- and actual geothermal activity that includes: thermal springs, fossil sinter deposits and hydrothermal petroleum manifestations. Thermal springs occur both inside and outside the lake. The spring water in out-shore thermal springs around Lake Chapala is carbonate (Medina-Heredia A, 1986). To the NE area is San Luis Agua Caliente (69°C; ~ 240 mg L-1 [HCO3]1) in the NW at Jocotepec (36°C; ~263mg L-1 [HCO3]-); in the South we find Tuxcueca and Tizap n El Alto (30°C; 193 mg L-1 [HCO3]-). However, there is an exception, the spring water at the San Juan Cosal sector (North), which is sulfate (64-83°C; ~479 mg L-1, [SO4]-2). Examples of in-shore thermal springs are "Los Gorgos" (near South shore) and "El Fuerte" (near East shore and temporary "out-shore" because of actual severe drought); the characterisation of water of this in-shore sites is in progress. On the SE shore and five km NW from Regules village, outcrops a carbonate deposit named "La Calera". This carbonate fossil sinter outcrops 2 km in E-W direction and 600 m in N-S direction and overlays andesitic rock. With a thickness of approximately 5m and a roughly horizontal attitude, the carbonated sinter material is characterized by both massive and banded structure. When massive, it is colored in yellow brownish and grey and elsewhere it shows a pseudo-brecciated structure and when banded, alternated of yellow and dark millimetre bands can be seen; is characterized by vuggy porosity and silica (quartz and chalcedony) vein lets. Under microscope a pseudo-micritic texture is observed; vugs coated by iron oxides, are filled with calcite, and/or quartz, chalcedony and clay minerals. Six samples of carbonate of "La Calera" deposit were analysed for their stable isotopes (LODC-UParis VI). From δ 13

  7. Lake Charles CCS Project

    SciTech Connect

    Leib, Thomas; Cole, Dan

    2015-06-30

    In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture and Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO2 generated in a large industrial gasification process and sequester the CO2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials

  8. Quaternary palaeoenvironments and multi-storey valley fill architecture along the Mezen and Severnaya Dvina river valleys, Arkhangelsk region, NW Russia

    NASA Astrophysics Data System (ADS)

    Jensen, Maria A.; Demidov, Igor N.; Larsen, Eiliv; Lyså, Astrid

    2009-11-01

    The modern Severnaya Dvina and Mezen river systems in the Arkhangelsk region, NW Russia, are located within extensive palaeovalley systems. The palaeovalleys form depressions in bedrock and have controlled the drainage systems in the area at least since the Last Interglacial. Vertically stacked marine to fluvial sediments reflect deposition during fluctuating climate and sea levels. A compilation of lithostratigraphical data collected during the last decade has been coupled with bedrock topography and geomorphology from satellite images in order to describe the valley fill architecture for the two valley systems. Each system has been divided into a number of depositional units (storeys) separated by incision/non-deposition and used to investigate the timing of aggradational versus incisional phases. Time constraints for each phase are provided by optically stimulated luminescence (OSL) ages, and aggradation and incision are linked to independent records of climate and sea level change. The pattern of aggradation and erosion is regional and primarily driven by episodes of increasing and decreasing sediment supply. Aggradation is correlated to times of deglaciation with high sediment supply from the ice margin, release of sediment from ice-dammed lakes and low vegetation and degradation of permafrost on the flood plain. Incision is related to cold intervals with low sediment supply, delayed incision due to isostatic uplift and drainage of ice-dammed lakes. Relative sea level change controls the distribution of marine deposits, which show significant regional variations due to variable isostatic response across the region. Sea level change plays a limited role for fluvial aggradation/incision in the study area.

  9. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    SciTech Connect

    Wright, P.J.; Tillitt, D.E.

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  10. Holocene lake-level fluctuations of Lake Aricota, Southern Peru

    USGS Publications Warehouse

    Placzek, C.; Quade, Jay; Betancourt, J.L.

    2001-01-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ???2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

  11. Gillnet selectivity for lake trout (Salvelinus namaycush) in Lake Superior

    USGS Publications Warehouse

    Hansen, Michael J.; Madenjian, Charles P.; Selgeby, James H.; Helser, Thomas E.

    1997-01-01

    Gillnet selectivity for lake trout (Salvelinus namaycush) was estimated indirectly from catches in nets of 102-, 114-, 127-, 140-, and 152-mm stretch measure. Mesh selectivity was modeled as a nonlinear response surface that describes changes in the mean, standard deviation, and skewness of fish lengths across mesh sizes. Gillnet selectivity for lake trout was described by five parameters that explained 88% of the variation in wedged and entangled catches, 81% of the variation in wedged catches, and 82% of the variation in entangled catches. Combined catches of wedged and entangled lake trout were therefore described more parsimoniously than separate catches of wedged and entangled lake trout. Peak selectivity of wedged and entangled fish increased from 588 to 663 mm total length as mesh size increased from 102 to 152 mm, and relative selectivity peaked at a total length of 638 mm. The estimated lake trout population size-frequency indicated that gillnet catches were negatively biased toward both small and large lake trout. As a consequence of this bias, survival of Lake Superior lake trout across ages 9-11 was underestimated by about 20% when the catch curve was not adjusted for gillnet selectivity.

  12. Geographical distributions of lake trout strains stocked in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Schaner, Ted

    1996-01-01

    Geographical distributions of lake trout (Salvelinus namaycush) stocked at seven locations in U.S. waters and at four locations in Canadian waters of Lake Ontario were determined from fish caught with gill nets in September in 17 areas of U.S. waters and at 10 fixed locations in Canadian waters in 1986-95. For fish of a given strain stocked at a given location, geographical distributions were not different for immature males and immature females or for mature males and mature females. The proportion of total catch at the three locations nearest the stocking location was higher for mature fish than for immature fish in all 24 available comparisons (sexes combined) and was greater for fish stocked as yearlings than for those stocked as fingerlings in all eight comparisons. Mature fish were relatively widely dispersed from stocking locations indicating that their tendency to return to stocking locations for spawning was weak, and there was no appreciable difference in this tendency among strains. Mature lake trout were uniformly distributed among sampling locations, and the strain composition at stocking locations generally reflected the stocking history 5 to 6 years earlier. Few lake trout moved across Lake Ontario between the north and south shores or between the eastern outlet basin and the main lake basin. Limited dispersal from stocking sites supports the concept of stocking different genetic strains in various parts of the lake with the attributes of each strain selected to match environmental conditions in the portion of the lake where it is stocked.

  13. HABITAT: LAKE SUPERIOR - STATE OF THE LAKE 2005

    EPA Science Inventory

    This presentation briefly describes the state of research and management in Lake Superior concerning fisheries and their association to habitat. It discusses a general habitat classification for the lake and an increasing interest in the nearshore, summarizing the status of cont...

  14. Biology of young lake trout (Salvelinus namaycush) in Lake Michigan

    USGS Publications Warehouse

    Van Oosten, John; Eschmeyer, Paul H.

    1956-01-01

    Experimental fishing with gill nets of 5 mesh sizes (2 3/8 to 3 inches) in Lake Michigan in 1930-32 yielded more than 16,000 young lake trout. Data are presented here on age, growth, length-weight relationship, abundance, geographical and bathymetric distribution, and other details of their biology.

  15. The near extinction of lake trout in Lake Michigan

    USGS Publications Warehouse

    Eschmeyer, Paul H.

    1957-01-01

    Comparisons in 1949 and 1950 of numbers of legal-sized lake trout caught in large-mesh nets with numbers of small fish taken in chub nets showed that both large and small lake trout declined over the same period, and that by these years the decline may have been greater among small than among legal-sized fish.

  16. Delineation of sympatric morphotypes of lake trout in Lake Superior

    USGS Publications Warehouse

    Moore, Seth A.; Bronte, Charles R.

    2001-01-01

    Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

  17. ARE LAKES GETTING WARMER? REMOTE SENSING OF LARGE LAKE TEMPERATURES

    EPA Science Inventory

    Recent studies (Levitus et al., 2000) suggest a warning of the world ocean over the past 50 years. Freshwater lakes could also be getting warmer but thermal measurements to determine this are lacking. Large lake temperatures are vertically and horizontally heterogeneous and vary ...

  18. The Lake Ohrid SCOPSCO project

    NASA Astrophysics Data System (ADS)

    Wagner, Bernd; Wilke, Thomas; Krastel, Sebastian; Zanchetta, Giovanni; Sulpizio, Roberto; Leng, Melanie J.; Francke, Alexander; Baumgarten, Henrike; Cvetkoska, Aleksandra; Giacco, Biagio; Lacey, Jack H.; Leicher, Niklas; Levkov, Zlatko; Lindhorst, Katja; Reed, Jane M.; Zhang, Xiaosen; Sadori, Laura; Vogel, Hendrik; Wagner-Cremer, Friederike; Wonik, Thomas

    2015-04-01

    The ICDP SCOPSCO project at Lake Ohrid in Macedonia and Albania was one of the most successful lake drilling campaigns worldwide. Drilling took place from April to June 2013 and yielded more than 2000 m of sediments from four different sites in the lake. The maximum penetration was 569 m below lake floor and the overall recovery at all drill sites was > 95 %. Almost two years after the drilling operation, core opening and processing as well as biological and geological analyses are still ongoing. However, most of the cores from the main drill site, the so-called DEEP site in the centre of the lake, are meanwhile opened and reveal a unique record of lake history. The extraordinary quality of seismic, borehole logging and core data allows us to achieve the major goals of the SCOPSCO project. Seismic data, diatoms and coarse-grained sediments in the basal cores indicate that Lake Ohrid had no marine origin, as it was speculated in the past. The data show that Lake Ohrid established in a highly dynamic pull-apart basin with varying fluvial and shallow water conditions. On top of these basal sediments, borehole logging data, XRF scanning data, carbonate, and the amount of organic matter indicate a complete and high resolution succession of glacial / interglacial cycles and interspersed stadials and interstadials. This allows us to determine the establishment of Lake Ohrid by means of chronostratigraphic tuning to about 1.3 to 1.5 Ma ago. Additional, independent age control is given by paleomagnetic data and by numerous tephra layers, which can be correlated with well-dated proximal tephra deposits in Italy. The uppermost 350 m of the sediment record contain more than 30 tephras, which makes the Lake Ohrid record to the rosetta stone of distal Italian tephra deposits in the Balkan region. The unique sediment record of Lake Ohrid is fundamental to obtain crucial information on the overall goal of the SCOPSCO project, i.e. to clarify why Lake Ohrid has one of highest

  19. Great Salt Lake sets record

    NASA Astrophysics Data System (ADS)

    Katzoff, Judith A.

    The level of the Great Salt Lake, Utah, broke its 1873 record on May 12, 1986, rising to 1283.7 m above mean sea level, according to the U.S. Geological Survey (USGS). Heavy snowpack remains in the lake's drainage basin, and the lake is likely to continue rising into June. “It could well go up another foot [i.e., ˜0.3 m],” this season, according to Ted Arnow, USGS district chief in Utah.The Utah state legislature convened a special session on May 13 to discuss measures to control the flooding. Last year, the legislature began to consider funding a plan to pump water from the Great Salt Lake to form a large, shallow pond in the desert 48 km to the west. Because the lake's level was predicted to drop this year, however, the lawmakers postponed action on the issue (Eos, September 10, 1985, p. 641). The Rose Park area of Salt Lake City, which lies below the lake's current level, has been diked, but groundwater is backing up into Rose Park and has to be pumped out over the dikes, Arnow said. Also, trains that use the Southern Pacific railroad causeway, which crosses the lake, have had to be temporarily rerouted south of the lake during storms. The causeway has been progressively raised since 1983, but engineers now say that they can raise it no further because the added weight will make it sink into the lake, Arnow said. If the lake rises much higher, the interstate highway that runs by it might also have to shut down temporarily during storms, he added.

  20. Feeding competition between larval lake whitefish and lake herring

    USGS Publications Warehouse

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

    The potential for competition for food between larval lake whitefish (Coregonus clupeaformis) and lake herring (C. artedi) 1- to 8-wk of age was explored in a series of 1-h laboratory feeding studies. Feeding started at 2-wk post-hatch. Learning and fish size appear to be more important than prey density at the onset of feeding. Species differed in their feeding behavior and consumption noticeably by 5-wk and substantially by 8-wk. Lake whitefish generally were more aggressive foragers than lake herring, attacking and capturing more prey. At high plankton density at 8-wk, lake herring feeding was depressed in mixed-fish treatments. This difference in competitive food consumption between the two coregonids occurs at a critical life stage, and when combined with other biotic and abiotic factors, may have a significant impact on recruitment.

  1. Forecasting Lake-Effect Snow in the Great Lakes Using NASA Satllite Data

    NASA Technical Reports Server (NTRS)

    Cipullo, Michelle; Molthan, Andrew; Shafer, Jackie; Case, Jonathan; Jedlovec, Gary

    2011-01-01

    This slide presentation reviews the forecast of the lake effect snow in the Great Lakes region using models and infrared estimates of Great Lake Surface Temperatures (GLSTs) from the MModerate Resolution Imaging Spectroradiometer (MODIS) instrument on Terra and Aqua satellites, and other satellite data. This study analyzes Lake Erie and Lake Ontario which produce storm total snowfall ranged from 8-18 inches off of Lake Ontario and 10-12 inches off of Lake Erie for the areas downwind.

  2. Genetic and tagging evidence for movement of walleyes between Lake Erie and Lake St. Clair

    USGS Publications Warehouse

    Todd, Thomas N.; Haas, Robert C.

    1993-01-01

    Walleyes (Stizostedion vitreum vitreum) from Lake Erie differed in allele frequencies from walleyes in Lake St. Clair (N = 1,680; 25 loci); however, only slight differences were found among walleyes from different spawning sites in each lake. Analyses of allele frequency data from samples of nonspawning walleyes taken in Lake St. Clair provided conditional maximum likelihood estimates that 86% of these walleyes were from Lake St. Clair and 14% from Lake Erie (SD = 19.7%) in 1983 and that 63% were from Lake St. Clair and 37% were from Lake Erie (SD = 20.0%) in 1984. About 30% of 1,159 recoveries of walleyes tagged in Lake Erie were taken from the Detroit River northward to southern Lake Huron, thus demonstrating extensive mixing of stocks from Lake Erie and Lake St. Clair. Additionally, tags recovered from the upper half of the St. Clair River provided an estimate of mixed stock composition of 76% Lake St. Clair fish and 24% Lake Erie fish. Analyses of tags returned during successive spawning seasons showed that walleyes strongly tended to return to suspected natal spawning areas. The tagging data thus corroborate the genetic evidence that walleye stocks from Lake St. Clair and Lake Erie are different, and that large numbers of Lake Erie walleyes enter Lake St. Clair during nonspawning seasons and return to their Lake Erie spawning sites each year. Western Lake Erie and Lake St. Clair walleyes should be considered as separate stocks for management purposes.

  3. Pyramid Lake Renewable Energy Project

    SciTech Connect

    John Jackson

    2008-03-14

    The Pyramid Lake Paiute Tribe is a federally recognized Tribe residing on the Pyramid Lake Reservation in western Nevada. The funding for this project was used to identify blind geothermal systems disconnected from geothermal sacred sites and develop a Tribal energy corporation for evaluating potential economic development for profit.

  4. Stream, Lake, and Reservoir Management.

    PubMed

    Mei, Ying; Chang, Chein-Chi; Dong, Zhanfeng; Wei, Li

    2016-10-01

    This review on stream, lake, and reservoir management covers selected 2015 publications on the focus of the following sections: • Biota • Climate effect • Models • Remediation and restoration • Reservoir operations • Stream, Lake, and Reservoir Management • Water quality.

  5. The Great Lakes Food Web.

    ERIC Educational Resources Information Center

    Baker, Marjane L.

    1997-01-01

    Presents a play for students in grades four to nine that incorporates the scientific names, physical characteristics, feeding habits, interactions, and interdependence of the plants and animals that make up the Great Lakes food web to facilitate the learning of this complex system. Includes a Great Lakes food web chart. (AIM)

  6. "Lake Woebegone," Twenty Years Later

    ERIC Educational Resources Information Center

    Cannell, John Jacob

    2006-01-01

    Almost 20 years ago, the author wrote--and then privately published--the two "Lake Woebegone" reports, named after Garrison Keillor's mythical Minnesota town where "all the women are strong, all the men are good-looking, and all the children are above average." The first "Lake Woebegone" report documented that all 50 states were testing above the…

  7. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    SciTech Connect

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  8. NATIONAL LAKE ASSESSMENT MONITORING DESIGN

    EPA Science Inventory

    The USEPA designed the National Lake Assessment in 2005-6 with field sampling being completed in 2007. The objective of the assessment is to estimate the ecological condition of lakes and reservoirs nationally. The objective of this paper is to describe the national survey desi...

  9. An urban lake remediation experiment

    SciTech Connect

    Castelli, S.E.; Gardner, K.H.; Jennings, A.A.

    1998-07-01

    Circumstances provided the opportunity to study a small urban lake as the surrounding municipalities attempted to improve its aesthetic quality by dredging. This manuscript focuses primarily on the sediments in the system: accumulation rates, the expected dynamics of the lake bed drying process, and the influence of the sediments on water quality.

  10. Stream, Lake, and Reservoir Management.

    PubMed

    Mei, Ying; Chang, Chein-Chi; Dong, Zhanfeng; Wei, Li

    2016-10-01

    This review on stream, lake, and reservoir management covers selected 2015 publications on the focus of the following sections: • Biota • Climate effect • Models • Remediation and restoration • Reservoir operations • Stream, Lake, and Reservoir Management • Water quality. PMID:27620102

  11. Europa's Great Lakes

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.

  13. Choking Lake Winnipeg

    NASA Astrophysics Data System (ADS)

    Byrne, J. M.; Little, L. J.; Dodgson, K. A.; MacDonald, R. J.; Graham, J.

    2009-12-01

    The problems of waterway eutrophication and coastal zone hypoxia are reaching epidemic proportions. Fresh water and coastal marine environments around the world are suffering unprecedented pollution loadings. We are developing an education program to address the dramatic need for public, community and K-12 education about the harsh impacts of elevated nutrient loads on fresh and marine water environments. The Lake Winnipeg watershed is adopted as the poster child of fresh water eutrophication in western North America. The watershed, one of the largest on the continent, is in rapid decline due to pollution, population pressures and water diversion. A concerted education program is needed to change personal and society actions that negatively impact the Winnipeg watershed; and the confluence of the watershed - Lake Winnipeg. But the education program goes beyond Lake Winnipeg. Negative impacts of nutrient loads are adversely affecting environments right to the oceans. Major dead zones that are expanding on our continental shelves due to nutrient overloading threaten to coalesce into extensive regions of marine life die-off. This presentation outlines the documentary education production process under development. We are building a series of Public Service Announcements (PSAs) for national television networks. The PSAs will direct educators, stakeholders and citizens to an associated website with educational video clips detailing the issues of eutrophication and hypoxia. The video clips or webisodes, present interviews with leading scientists. The discussions address the causes of the problems, and presents workable solutions to nutrient overloads from a variety of sources. The webisodes are accompanied by notes and advice to teachers on ways and means to use the webisodes in classrooms. The project is fully funed by a group of Canadian Community Foundations, with the understanding the work wil be available free to educators anywhere in the world. Our education

  14. Seasonal bathythermal distribution of juvenile lake trout in Lake Ontario

    USGS Publications Warehouse

    Elrod, Joseph H.; Schneider, Clifford P.

    1987-01-01

    Bathythermal distributions of hatchery-reared lake trout (Salvelinus namaycush) of three genetic strains (Lake Superior; Clearwater Lake, Manitoba; and Seneca Lake, New York) were described from catches with bottom trawls in Lake Ontario during April-May, June, July-August, and October, 1978–1984. This work was part of a program to evaluate post-stocking performance of hatchery-reared fish and identify strains for continued use in rehabilitation of lake trout in Lake Ontario. All age groups of Lake Superior fish were in deeper water in April-May than in June each year; mean depth of capture was greatest at age II and became progressively shallower at ages III and IV. Mean depth of capture in April-May was positively correlated with severity of the preceding winter as judged by heating degree days and average wind speed. During July-August, the fish were concentrated between the epilimnion and 50 m, with no consistent trend in depth by age; however, 92% were captured at water temperatures of 12°C or lower. Mean temperatures of capture for Lake Superior fish during the four respective sampling periods were 3.9, 7.5, 6.9, and 9.5° C for fish of age II and 3.9, 8.4, 6.9, and 8.7° C for fish of age III. The age-II Clearwater Lake fish were consistently at shallower depths than age-II Lake Superior fish. Mean temperatures of capture were 4.2, 9.7, 9.6, and 10.7° C during the four respective sampling periods; during July-August, 91% were taken in water of 12° C or lower. The distribution of Seneca Lake fish was similar to that of the Lake Superior strain. Mean temperatures at which the three strains were captured were well below published preferred temperatures of yearlings in the laboratory. Annual variations in depth distributions during a given season were probably due to differing thermal regimes resulting from annual variations in the weather.

  15. L-Lake macroinvertebrate community

    SciTech Connect

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  16. Selected species of the family Diastylidae (Cumacea, Peracarida, Crustacea) from the deep-sea of the NW Pacific.

    PubMed

    Mühlenhardt-Siegel, Ute; Lavrenteva, Anna V

    2015-05-11

    New species of the genera Diastylis, Divacuma and Leptostylis are described. Also a new species of the genus Pseudoleptostyloides, known from the Atlantic, is described for the NW Pacific. Additional information is given on Leptostyloides quadridentata.

  17. Chemiluminescent lateral-flow immunoassays by using in-situ synthesis of CdS NW photosensor.

    PubMed

    An, Byoung-Gi; Kim, Hong-Rae; Kang, Min-Jung; Park, Jae-Gwan; Chang, Young Wook; Pyun, Jae-Chul

    2016-07-13

    A hypersensitive CdS nanowire (NW) photosensor was fabricated by an in-situ synthesis process that involved the direct synthesis of CdS NWs on an interdigitated electrode (IDE). Analysis of the photoresponse properties showed that the newly synthesized photosensor had enhanced sensitivity and a highly reproducible photoresponse compared to photosensors prepared from CdS NW suspensions. The NW photosensor was applied to measure the chemiluminescence of luminol, and the sensitivity was compared to a commercial photosensing system. Finally, the feasibility of the CdS NW photosensor for the application to the medical diagnosis of the human hepatitis B surface antigen (hHBsAg) was demonstrated using a lateral-flow immunoassay with a chemiluminescent signal band. PMID:27237842

  18. Morphological and optical data of AgNW embedded transparent conductive layer.

    PubMed

    Kim, Hong-Sik; Patel, Dipal B; Patel, Malkeshkumar; Kim, Joondong

    2016-12-01

    In this data article, morphological and optical data of AgNW encapsulated between ITO layers are presented to get insights into our article (DOI:10.1016/j.solmat.2016.04.038; Hong-Sik Kim, Pankaj Yadav, Malkeshkumar Patel, Hyunki Kim, Kavita Pandey, Joondong Kim, 2016) [1]. SEM images for the formation of AgNWs networks by number of spin coating are also presented. SEM photographs showing the surface morphologies before and after rapid thermal treatment of prepared samples have been presented. Apart from morphological data set, optical characteristics of this type of samples are given. The comparison plots of optical reflectance from AgNW encapsulated between ITO layers and bare ITO are given between the wavelength ranges from 300 to 1100 nm. At the end, transmittance and reflectance curves of native glass substrates used in this study are presented. PMID:27656670

  19. Preliminary Feasibility Assessment of Integrating CCHP with NW Food Processing Plant #1: Modeling Documentation

    SciTech Connect

    Hoffman, Michael G.; Srivastava, Viraj; Wagner, Anne W.; Makhmalbaf, Atefe; Thornton, John

    2014-01-01

    The Pacific Northwest National Laboratory (PNNL) has launched a project funded by the Bonneville Power Association (BPA) to identify strategies for increasing industrial energy efficiency and reducing energy costs of Northwest Food Processors Association (NWFPA) plants through deployment of novel combinations and designs of variable-output combined heat and power (CHP) distributed generation (DG), combined cooling, heating and electric power (CCHP) DG and energy storage systems. Detailed evaluations and recommendations of CHP and CCHP DG systems will be performed for several Northwest (NW) food processing sites. The objective is to reduce the overall energy use intensity of NW food processors by 25% by 2020 and by 50% by 2030, as well as reducing emissions and understanding potential congestion reduction impacts on the transmission system in the Pacific Northwest.

  20. Marine sedimentary record of Meltwater Pulse 1a along the NW Barents Sea continental margin

    NASA Astrophysics Data System (ADS)

    Giulia Lucchi, Renata; Sagnotti, Leonardo; Camerlenghi, Angelo; Macrì, Patrizia; Rebesco, Michele; Pedrosa, Maria Teresa; Giorgetti, Giovanna

    2016-04-01

    The upper continental slope of the Storfjorden-Kveithola Trough Mouth Fans (NW Barents Sea) contains a several m-thick late Pleistocene sequence of plumites composed of laminated mud interbedded with sand/silt layers. Radiocarbon ages revealed that deposition occurred during about 130 years at a very high sedimentation rate of 3.4 cm a-1, at about 7 km from the present shelf break. Palaeomagnetic and rock magnetic analyses confirm the existence of a prominent, short-living sedimentary event. The plumites appear laterally continuous and were correlated with the sedimentary sequences described west of Svalbard and neighbouring glacial depositional systems representing a major event at regional scale appointed to correspond to the deep-sea sedimentary record of Meltwater Pulse-1a. We also present new sedimentological and geochemical insights, and multi-beam data adding information on the palaeoenvironmental characteristics during MWP-1a and ice sheet decay in the NW Barents Sea.

  1. Looking for Larvae Above an Erupting Submarine Volcano, NW Rota-1, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Hanson, M.; Beaulieu, S.; Tunnicliffe, V.; Chadwick, W.; Breuer, E. R.

    2015-12-01

    In 2009 the first marine protected areas for deep-sea hydrothermal vents in U.S. waters were established as part of the Volcanic Unit of the Marianas Trench Marine National Monument. In this region, hydrothermal vents are located along the Mariana Arc and back-arc spreading center. In particular hydrothermal vents are located near the summit of NW Rota-1, an active submarine volcano on the Mariana Arc which was erupting between 2003 through 2010 and ceased as of 2014. In late 2009, NW Rota-1 experienced a massive landslide decimating the habitat on the southern side of the volcano. This presented an enormous natural disturbance to the community. This project looked at zooplankton tow samples taken from the water column above NW Rota-1 in 2010, searching specifically for larvae which have the potential to recolonize the sea floor after such a major disturbance. We focused on samples for which profiles with a MAPR sensor indicated hydrothermal plumes in the water column. Samples were sorted in entirety into coarse taxa, and then larvae were removed for DNA barcoding. Overall zooplankton composition was dominated by copepods, ostracods, and chaetognaths, the majority of which are pelagic organisms. Comparatively few larvae of benthic invertebrates were found, but shrimp, gastropod, barnacle, and polychaete larvae did appear in low numbers in the samples. Species-level identification obtained via genetic barcoding will allow for these larvae to be matched to species known to inhabit the benthic communities at NW Rota-1. Identified larvae will give insight into the organisms which can re-colonize the seafloor vent communities after a disturbance such as the 2009 landslide. Communities at hydrothermal vents at other submarine volcanoes in the Monument also can act as sources for these planktonic, recolonizing larvae. As the microinvertebrate biodiversity in the Monument has yet to be fully characterized, our project also provides an opportunity to better describe both

  2. Hydrological cycles and trends in the NW Argentine Andes since 1940

    NASA Astrophysics Data System (ADS)

    Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred

    2016-04-01

    Strong spatiotemporal variability characterizes the hydrometeorological pattern in the NW Argentine Andes, draining parts of the most populated and economically important areas of South America. During the summer monsoon season (DJF), the eastern flanks of the central Andes are characterized by deep convection, exposing them to extreme hydrometeorological events. These often result in floods and landslides with disastrous effects on the local populations. Here, we analyze river discharge to explore long-term hydrological variability in NW Argentine Andes and the linked climate controlling processes. We rely on 13 daily river discharge time series relevant to drainage basins spanning several size orders (102-104 km2) starting in 1914 and define different hydro-climate indices both for the mean and the extreme hydrological events. We apply quantile regression to investigate long-term trends and spectral analysis associated with cross-correlation with SST-based climate indices to identify links to large-scale climate variability modes. River discharge presents a pronounced and coherent variability signal in South America, particularly for wide drainage basins, such as the Amazon and Paraná/La Plata rivers, strongly associated to Pacific and Atlantic Oceans Sea Surface Temperature (SST) anomalies (i.e. ENSO, PDO, AMO). Our analysis evidences that in the NW Argentine Andes, mean discharge values are characterized by statistically significant, mostly positive, long-term trends since 1940, whereas the extreme events present a more non-unidirectional trend pattern. Also, coherent multi-annual to multi-decadal cycles characterizing the discharge pattern have been identified, suggesting that processes linked to SST anomaly-modes strongly control the hydrometeorology variability in the NW Argentina Andes.

  3. Double-gated Si NW FET sensors: Low-frequency noise and photoelectric properties

    NASA Astrophysics Data System (ADS)

    Gasparyan, F.; Khondkaryan, H.; Arakelyan, A.; Zadorozhnyi, I.; Pud, S.; Vitusevich, S.

    2016-08-01

    The transport, noise, and photosensitivity properties of an array of silicon nanowire (NW) p+-p-p+ field-effect transistors (FETs) are investigated. The peculiarities of photosensitivity and detectivity are analyzed over a wide spectrum range. The absorbance of p-Si NW shifts to the short wavelength region compared with bulk Si. The photocurrent and photosensitivity reach increased values in the UV range of the spectrum at 300 K. It is shown that sensitivity values can be tuned by the drain-source voltage and may reach record values of up to 2-4 A/W at a wavelength of 300 nm at room temperature. Low-frequency noise studies allow calculating the photodetectivity values, which increase with decreasing wavelength down to 300 nm. We show that the drain current of Si NW biochemical sensors substantially depends on pH value and the signal-to-noise ratio reaches the high value of 105. Increasing pH sensitivity with gate voltage is revealed for certain source-drain currents of pH-sensors based on Si NW FETs. The noise characteristic index decreases from 1.1 to 0.7 with the growth of the liquid gate voltage. Noise behavior is successfully explained in the framework of the correlated number-mobility unified fluctuation model. pH sensitivity increases as a result of the increase in liquid gate voltage, thus giving the opportunity to measure very low proton concentrations in the electrolyte medium at certain values of the liquid gate voltage.

  4. Airborne radioactivity survey of parts of Savery NW and Savery NE quadrangles, Carbon County, Wyoming

    USGS Publications Warehouse

    Henderson, J.R.

    1954-01-01

    The accompanying map shows the results of an airborne radioactivity survey in 266 square miles of Savery NW and Savery NE quadrangles, Wyoming. This area is part of a larger survey made in southern Carbon and Sweetwater Counties by the U. S. Geological Survey, November 9-24, 1953. The work was undertaken as part of a cooperative program with the U.S. Atomic Energy Commission.

  5. Mineralogy, geochemistry and genesis of the modern sediments of Seyfe Lake, Kırşehir, central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Önalgil, Nergis; Kadir, Selahattin; Külah, Tacit; Eren, Muhsin; Gürel, Ali

    2015-02-01

    Seyfe Lake (Kırşehir, Turkey) is located within a depression zone extending along a NW-SE-trending fault in central Anatolia. Evaporite and carbonate sediments occur at the bottom of the lake which is fed by high-sulfate spring and well waters circulating N-S through salt domes. The recent sediments of Seyfe Lake are deposited in delta, backshore, beach, mud-flat and shallow lake environments. In the mud-flat environment, calcite, gypsum, halite, and thenardite are associated with fine-grained detrital sediments. Sediments from the margin to the lake center are distributed as calcite, gypsum and halite ± thenardite, yielding an annular distribution pattern. An increase in Na2O, SO3, and S, and a decrease in CaO toward the lake center are due to sediment distribution. On the other hand, a positive correlation of SiO2 with MgO, K2O, Na2O, Al2O3, and Fe2O3 + TiO2 is attributed to the presence of smectite, illite and feldspar. In addition, a positive correlation of Sr and Ba with CaO is related to the amount of gypsum in the sediments. Strontium is associated with in situ gypsum crystals; it increases in the intermediate and central zones of the lake as a result of a relative increase in salinity toward the lake center. The association of Sr with gypsum in the sediments suggests that Ca and Sr were derived from Sr-bearing evaporites and their carbonate host rocks, which were the likely aquifers for the brine. The S- and O-isotopic compositions of sulfate crystals range from +19.1‰ to +21.7‰ and from +16.9‰ to +20.9‰ SMOW, respectively, suggesting precipitation in a closed lake system. A relative increase of oxygen and sulfur isotope ratios toward the lake center suggests dissolution of gypsum in the host rock, with contributions from circulating groundwater and sulfate reduction (possibly by bacterial reduction). 87Sr/86Sr isotope ratios range from 0.707286 to 0.707879, suggesting a non-marine Oligo-Pliocene evaporitic host rock source for precipitation in

  6. Time and Space Variations of Local Seismic Signals in the NW-Bohemia/Vogtland Swarm Region

    NASA Astrophysics Data System (ADS)

    Bouskova, A.; Horalek, J.; Fischer, T.; Hudova, Z.

    2003-04-01

    Local WEBNET stations in the NW-Bohemia/Vogtland earthquake swarm region provide high quality data, which make possible a detailed analysis of converted phases contained in the seismograms. Seismograms of local earthquakes display pronounced reflections or splitting of P- and S-waves. Some of the reflections could origin from the presence of fluids or a molten material at a short distance from the earthquake hypocentres, the other reflect the complex geological structure of the region. The existence of split phases can verify the anisotropy of earth crust in this area. The occurrence of secondary phases, similarly to the other attributes of seismic wave propagation (velocity ratio of P- and S- waves, wave back-azimuth), varies in time and space. This contribution presents the space and time changes of some of observed secondary phases in the local NW-Bohemia seismograms and also gives some possible interpretations of these phenomena. Consequently, we discuss the processes acting during earthquake swarms in the NW- Bohemia/Vogtland region and in the time intervals between swarm activity.

  7. New Early Paleozoic Paleomagnetic Poles From NW Argentina: a Reappraisal of Tectonic Models

    NASA Astrophysics Data System (ADS)

    Spagnuolo, C. M.; Rapalini, A. E.; Astini, R. A.

    2007-05-01

    A paleomagnetic study carried out on Early Ordovician volcanic units in the Famatina Ranges of NW Argentina yielded a pre-tectonic paleomagnetic pole at 32.7°S, 4.3°E, (5.6°/ 8.6°, N=14 sites) that is consistent with four previous Early Ordovician poles from the Famatina - Eastern Puna Eruptive Belt of NW Argentina. However, these five poles are rotated around 50° clockwise respect to the coeval reference pole of Gondwana. Our new results seem to confirm previous models of this belt as a paraauthocthonous rotated terrane on the southwestern margin of Gondwana. However, a recent paleomagnetic pole from the Late Cambrian Mesón Group, at the Eastern Cordillera of NW Argentina, corresponding to the Gondwana foreland (4.5°S, 359.0°E, dp=5.5°, dm=8.8°, n=26 samples) and preliminary paleopoles obtained from the same unit and the latest Cambrian - Early Ordovician Santa Victoria Group at other three localities in the same region, also indicate an anomalous pole position rotated some 40° clockwise respect to the reference pole for Gondwana. These results suggest that the postulated model of a rotated terrane for the Famatina-Eastern Puna belt must be reconsidered. Different alternative scenarios including the possibility of an Early Paleozoic displacement of the whole basement of the Eastern Sierras Pampeanas of Argentina ("Pampia") will be explored.

  8. Evidence for an Ancient Buried Landscape on the NW Rim of Hellas Basin, Mars

    NASA Technical Reports Server (NTRS)

    Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.; Mustard, John F.; Vincendon, Mathieu

    2010-01-01

    Hellas basin is the largest (2000+ km across) well-preserved impact structure on Mars and its deepest depositional sink [e.g., 1]. The Hellas rim and adjacent highlands are of special interest given the possibility of paleolakes on the basin floor [2-4], recent studies of potential localized fluvial/lacustrine systems [2, 5-17], and evidence for phyllosilicates around and within impact craters north of the basin [18-26]. We are producing a 1:1.5M-scale geologic map of eight MTM quadrangles (-25312, -25307, -25302, -25297, -30312, -30307, -30302, -30297) along Hellas NW rim. The map region (22.5-32.5degS, 45- 65degE) includes a transect across the cratered highlands of Terra Sabaea, the degraded NW rim of Hellas, and basin interior deposits of NW Hellas Planitia. No previous mapping studies have focused on this region, although it has been included in earlier global and regional maps [27-29].

  9. Mercury content and their risk assessment in farmed shrimp Litopenaeus vannamei from NW Mexico.

    PubMed

    Delgado-Alvarez, C G; Ruelas-Inzunza, J; Osuna-López, J I; Voltolina, D; Frías-Espericueta, M G

    2015-01-01

    The main objective of this study was to evaluate the total mercury content in hepatopancreas and edible muscle of the whiteleg shrimp Litopenaeus vannamei cultured along the NW coast of Mexico, and to evaluate the potential human health risk due to their consumption. Samples were obtained between May and June 2010 in 26 shrimp farms from the three most important shrimp-producing states of NW Mexico, and total Hg was analyzed after reduction with SnCl2 in a mercury analyzer. The ranges of Hg concentrations of the hepatopancreas were 0.101±0.03-0.184±0.13 μg g(-1) in Sonora, 0.077±0.055-0.813±0.363 μg g(-1) in Sinaloa and 0.139±0.037-0.791±0.33 μg g(-1) in Nayarit. In the muscle, values were from 0.078±0.02 to 0.539±0.09 μg g(-1) in Sonora, 0.154±0.03-0.861±0.423 μg g(-1) in Sinaloa and 0.121±0.041-1.48±0.44 μg g(-1) in Nayarit. Considering the concentrations of Hg in the muscle and the national consumption rate, shrimp farmed in NW Mexico does not represent a risk for human health (HQ<1).

  10. Geochemistry of thermal fluids in NW Honduras: New perspectives for exploitation of geothermal areas in the southern Sula graben

    NASA Astrophysics Data System (ADS)

    Capaccioni, Bruno; Franco, Tassi; Alberto, Renzulli; Orlando, Vaselli; Marco, Menichetti; Salvatore, Inguaggiato

    2014-06-01

    The results of a geochemical survey on thermal waters and, for the first time for this site, gas discharges in five geothermal sites (Azacualpa "La Cueva", Río Ulua, Río Gualcarque, El Olivar and Laguna de Agua Caliente) in NW Honduras are here presented and discussed. El Olivar and Laguna de Agua Caliente, in the southern part of the Sula graben are very close to a Quaternary basaltic field, whereas Azacualpa "La Cueva", Río Ulua and Río Gualcarque, located to the southwest of the Yojoa Lake, direcly emerge from the Cretaceous limestone deposits. The measured temperatures range between 37.5 and 104.8 °C. "Mature", alkaline, Na-SO4 thermal waters discharge from Azacualpa "La Cueva", while those from El Olivar and Laguna de Agua Caliente are "immature" and show a Na-HCO3 composition. Chemical equilibria of waters and gases from the Azacualpa "La Cueva" thermal springs indicate temperatures ranging from 150 to 200 °C. Conversely, gas discharges from El Olivar and Laguna de Agua Caliente have attained a partial chemical equilibrium in the liquid phase at slightly higher temperatures (200-250 °C), although gas-gas faster reactions involving CO seem to be adjusted in an isothermally separated vapor phase. Unlike Azacualpa, SiO2 geothermometer at El Olivar and Laguna de Agua Caliente indicates equilibrium temperatures for the liquid phase much lower than those calculated for the gas phase (≤ 120 °C). We conclude that thermal waters from the Azacualpa area likely represent the direct emergence of a water dominated reservoir having temperatures ≤ 150-200 °C. By contrast, at El Olivar and Laguna de Agua Caliente hot springs are supplied by a boiling shallow aquifer fed by a vapor phase rising from a steam-dominated zone. The above geochemical model is consistent with a geothermal reservoir hosted within the Cretaceous carbonate sequences of the Yojoa Group in the whole investigated sites. The reservoir extensively crops out in the Azacualpa area whereas the

  11. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Special requirements, Lake Campbell and... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports. Each person operating an aircraft to or from Lake Campbell or Sixmile Lake Airport shall conform to the...

  12. 75 FR 20920 - Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Grand Prix, Lake Havasu, AZ... temporary safety zone upon the navigable waters of Lake Havasu on the Colorado River in Lake Havasu City, Arizona for the Lake Havasu Grand Prix. This temporary safety zone is necessary to provide for the...

  13. 75 FR 13232 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-19

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... Pipe from Lake Mead throughout 2010. This safety zone is necessary to ensure non-authorized...

  14. 77 FR 33309 - Safety Zone; Race on the Lake, Onondaga Lake, Syracuse, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-06

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Race on the Lake, Onondaga Lake, Syracuse... temporary safety zone on Onondaga Lake, Syracuse, NY. This safety zone is intended to restrict vessels from a portion of Onondaga Lake during the Race on the Lake powerboat races. This temporary safety...

  15. 78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ... temporary safety zone within the navigable waters of Lake Havasu and the London Bridge Channel for the Lake... Triathlon will consist of 600 participants. The waterside swim course consists of 1500 meters in Lake...

  16. 77 FR 9652 - Proposed CERCLA Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-17

    ... AGENCY Proposed CERCLA Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake Linden... administrative settlement for recovery of past response costs concerning the Lake Linden Superfund Site in Lake..., Chicago, Illinois, C-14J, 60604, (312) 886-6609. Comments should reference the Lake Linden Superfund...

  17. 76 FR 2579 - Safety Zone; Lake Mead Intake Construction, Lake Mead, Boulder City, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-14

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Mead Intake Construction, Lake Mead... establishing a safety zone on the navigable waters of Lake Mead in support of the construction project for Lake... blasting operations for the placement of a water intake pipe in Lake Mead during the first 6 months of...

  18. PLAT X41601 EAST (SALT LAKE CITY CEMETERY LOCATER), SALT LAKE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PLAT X-4-160-1 EAST (SALT LAKE CITY CEMETERY LOCATER), SALT LAKE CITY, UT. VIEW LOOKING SOUTH AT CEMETERY BETWEEN OLIVE STREET (1020 EAST) AND 1000 EAST STREET, REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 12049, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  19. EPA Research Strengthens Great Lakes Restoration Initiative

    EPA Science Inventory

    As the largest group of freshwater lakes on Earth, the Great Lakes (Lakes Erie, Huron, Michigan, Ontario and Superior) are a source of economic prosperity, recreation and raw materials. Human activity, however, has resulted in pollution and other stressors. The Great Lakes curren...

  20. 27 CFR 9.127 - Cayuga Lake.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area...

  1. 27 CFR 9.127 - Cayuga Lake.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area...

  2. 27 CFR 9.127 - Cayuga Lake.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area...

  3. 27 CFR 9.127 - Cayuga Lake.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Cayuga Lake. 9.127 Section... Lake. (a) Name. The name of the viticultural area described in this section is “Cayuga Lake.” (b) Approved maps. The appropriate map for determining the boundaries of the Cayuga Lake viticultural area...

  4. 33 CFR 125.08 - Great Lakes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Great Lakes. 125.08 Section 125... VESSELS § 125.08 Great Lakes. The term Great Lakes as used in the regulations in this subchapter shall include the Great Lakes and their connecting and tributary waters....

  5. Increased piscivory by lake whitefish in Lake Huron

    USGS Publications Warehouse

    Pothoven, Steven A.; Madenjian, Charles P.

    2013-01-01

    We evaluated the diet of Lake Whitefish Coregonus clupeaformis in Lake Huron during 2002–2011 to determine the importance of Round Goby Neogobius melanostomus and other fish as prey items. Lake Whitefish that had reached approximately 400 mm in length incorporated fish into their diets. The overall percentage of adult Lake Whitefish in Lake Huron that had eaten fish increased from 10% in 2002–2006 to 20% in 2007–2011, with a corresponding decrease in the frequency of Lake Whitefish that ate Dreissena spp. from 52% to 33%. During 2002–2006, Round Goby (wet mass, 38%), sculpins (Cottidae) (34%), and Ninespine Stickleback Pungitius pungitius (18%) were the primary fish eaten, whereas Round Goby accounted for 92% of the fish eaten in 2007–2011. Overall, Round Goby were found in the fewest Lake Whitefish stomachs in the north region of Lake Huron (6%) and in the most in the central (23%) and south (19%) regions of the lake. In the central region, Round Goby were eaten during all seasons that were sampled (spring through fall). In the south region, Round Goby were eaten only in the winter and spring but not in the summer when Dreissena spp. and spiny water flea Bythotrephes longimanus dominated the diet. Based on the 2007–2011 diet composition, an individual Lake Whitefish would need to have increased their consumption relative to that in 1983–1994 by 6% in the north region, 12% in the central region, and 41% in the southern region in order to achieve the same growth that was observed before dreissenid mussels arrived. However, Lake Whitefish weight adjusted for length only increased by 2% between 2002–2006 and 2007–2011 in the central region, decreased by 4% in the northern region, and remained constant in the southern region. This suggests that a shift toward more frequent piscivory does not necessarily improve the condition of a generalist feeder like Lake Whitefish.

  6. Chandra and Spitzer Observations of the NW Filament of SN 1006

    NASA Astrophysics Data System (ADS)

    Williams, Brian J.; Winkler, P. F.; Katsuda, S.; Blair, W. P.; Borkowski, K. J.; Ghavamian, P.; Long, K. S.; Petre, R.; Raymond, J. C.; Reynolds, S. P.

    2013-01-01

    We present results from Chandra and Spitzer observations of the NW region of SN1006. Deep X-ray observations from Chandra (companion paper by Winkler et al.) allow us to study the variation in shock velocity around the shell and elucidate the physics of diffusive shock acceleration, and both non-thermal and thermal X-ray emission, in unprecedented detail. Along the thermally-dominated NW limb, X-ray proper motions over an 11-yr baseline indicate a shock velocity of about 3000 km/s, consistent with measurements from optical studies. But even in the NW we find a few regions dominated by non-thermal emission, and proper motions of these small filaments show a velocity of 5000 km/s, virtually identical to that seen along the synchrotron-dominated NE limb. Higher shock speeds in the non-thermal regions than in thermal ones are consistent with the theoretical view of diffusive shock acceleration that faster shocks can enhance synchrotron X-ray emission. The existence of thermal and non-thermal regions, with strongly contrasting X-ray spectra and proper motions, in close proximity to one another indicates that interstellar density inhomogeneities exist on pc scales, even at the location of SN 1006, 550 pc above the Galactic plane. Spitzer IR imaging and spectroscopic observations also indicate an inhomogeneous ISM surrounding SN1006, where the shock has recently encountered a denser region to the NW. The 24 micron image from MIPS clearly shows faint filamentary emission just interior to the NW Balmer filaments that delineate the present position of the expanding shock. This is the first detection of IR radiation from SN 1006 and clearly indicates an origin in shock-heated interstellar dust grains. The spectrum confirms a warm dust origin for the IR emission, and a model of the dust spectrum is consistent with the pre-shock density of 1 cm^-3 derived from optical and X-ray studies. The dust-to-gas mass ratio in the pre-shock ambient medium is a factor of several lower than

  7. Rehabilitation of Delavan Lake, Wisconsin

    USGS Publications Warehouse

    Robertson, Dale M.; Goddard, Gerald L.; Helsel, D.R.; MacKinnon, Kevin L.

    2009-01-01

    A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake, Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake, (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake, the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems.

  8. Forest blowdown and lake acidification

    SciTech Connect

    Dobson, J.E.; Rush, R.M. ); Peplies, R.W. )

    1990-01-01

    The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of {minus}0.67 and {minus}0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry.

  9. Microplastics in Taihu Lake, China.

    PubMed

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake. PMID:27381875

  10. Microplastics in Taihu Lake, China.

    PubMed

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.

  11. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and Lake Mohave; restricted areas—(1) The areas. That portion of Lake Mead extending 700 feet upstream...

  12. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and Lake Mohave; restricted areas—(1) The areas. That portion of Lake Mead extending 700 feet upstream...

  13. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and Lake Mohave; restricted areas—(1) The areas. That portion of Lake Mead extending 700 feet upstream...

  14. Structural analysis of Nalagarh lobe, NW Himalaya: implication of thrusting across tectonic edge of NW limb of Nahan salient, Himachal Pradesh, India

    NASA Astrophysics Data System (ADS)

    Bhakuni, S. S.; Philip, G.; Suresh, N.

    2016-08-01

    The Main Boundary Fault (MBF), convex towards southwest, forms the leading edge of the Nahan salient. Near the southern end of an oblique ramp, a lobe-shaped physiographic front, named in this work as Nalagarh lobe, has developed across NW limb of salient. The lobe has formed across the MBF that separates the hanging wall Lower Tertiary Dharmsala rocks from the foot wall Upper Tertiary Siwalik rocks and overlying Quaternaries. In front of lobe Dharmsala, thrust fault splays (Splay-1 and Splay-2) and associated tectonic fabrics have developed within the Late Pleistocene fan deposit. Structural elements developed across the front of Nalagarh lobe are analysed with reference to evolution of lobe. With reference to the evolution of lobe, an unweathered ~15-m-high hanging wall or wedge top forms the uplifted and rejuvenated bedrock fault scarp of the MBF. Below the MBF, the fan deposit has underthrust along Splay-1. Later the Splay-2 formed within fan deposit near south of Splay-1. Geometry of the overturned limb of tight to isoclinal fault propagation fold, formed on Splay-2 plane, suggests that the fold formed by normal drag, produced by intermittent fault-slips along Splay-2. The displacement along Splay-2 offset the marker bed to ~1 m by which some clasts rotated parallel to the traces of brittle axial planes of fold. The variable fold geometry and style of deformation are analysed along length of thrust splays for 5 km. It is revealed that the lobe is bounded by transverse thrust faults along its NW and SE margins. The geometry of salient and oblique ramp suggests that the transverse thrust faults and associated transverse folds formed by right-lateral displacement along the NW limb of the salient. Marking the northern margin of the intermontane piggyback basin of Pinjaur dun, the MBF is interpreted to be an out-of-sequence thrust that has brought up the Lower Tertiary Dharmsala rocks over the Late Pleistocene fan deposit. The geometry of lobe and its bounding

  15. Monitoring Change in Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Naftz, David; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Carling, Gregory

    2013-08-01

    Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is of important economic value: Brine shrimp (Artemia franciscana) residing in Great Salt Lake support an aquaculture shrimp cyst industry with annual revenues as high as $60 million.

  16. Great Salt Lake, Utah, USA

    NASA Technical Reports Server (NTRS)

    1990-01-01

    As seen from space, the Great Salt Lake, Utah, USA (41.5N, 112.5W) appears as two separate bodies of water with a narrow divider in the middle. At the turn of the century, a railroad bridge without culverts, was built across the lake and ever since, the water and salinity levels have been uneqal on either side. Fed by snowmelt from the nearby Wasatch Mountains, the lake in recent years has had record high water levels, threatening to flood the local areas.

  17. RAINBOW LAKE WILDERNESS AND FLYNN LAKE WILDERNESS STUDY AREA, WISCONSIN.

    USGS Publications Warehouse

    Cannon, W.F.; Dunn, Maynard L.

    1984-01-01

    The Rainbow Lake Wilderness and Flynn Lake Wilderness study area in Wisconsin are contiguous and were studied as a unit. The rainbow Lake Wilderness contains a demonstrated resource of about 210,000 tons of commercial-quality peat in an area of substantiated peat resource potential. The Flynn Lake Wilderness study area contains a demonstrated resource of about 300,000 tons of commercial-quality peat in an area of substantiated peat resource potential. These deposits, however, are of limited importance because larger deposits of similar material are abundant outside the areas, closer to present markets. Rocks in the subsurface contain a low-grade copper resource identified by mining company exploration drilling. Although this is an area of substantiated copper resource potential, it is a low-grade resource, thin and generally at great depth.

  18. Lake trout in the Great Lakes: Basin-wide stock collapse and binational restoration

    USGS Publications Warehouse

    Hansen, Michael J.; Taylor, William W.; Ferreri, C. Paola

    1999-01-01

    The lake trout (Salvelinus namaycush) was important to the human settlement of each of the Great Lakes, and underwent catastrophic collapses in each lake in the nineteenth and twentieth centuries. The timing of lake trout stock collapses were different in each lake, as were the causes of the collapses, and have been the subject of much scientific inquiry and debate. The purpose of this chapter is to summarize and review pertinent information relating historical changes in Great Lakes lake trout stocks, binational efforts to restore those stocks, and progress toward stock restoration. This presentation attempts to generalize patterns across the Great Lakes, rather than to focus within each lake. Lake specific analyses have been used to understand lake specific causes and effects, but there is continuing debate about some of these causes and effects. A basinwide review may suggest mechanisms for observed changes that are not evident by lake specific analysis.

  19. Climate, Hydrology, and Lake Sediment

    NASA Astrophysics Data System (ADS)

    Ito, E.; Forester, R. M.

    2008-12-01

    Components of lake sediment such as endogenic minerals, organic compounds, and fossils as well as chemistry and isotopes of those components are sources of information about past continental climate. No matter the size of the lake, the components of their sedimentary records reflect some integration of catchment processes operating on the landscape, within the ground water, and in the lake. Climate change influences and often drives change among these processes, yet the integration of the processes commonly yields unique records in lakes residing under the same climate. An estimate of the actual climate history from lake records as opposed to the apparent climate history from a given lake depends on how well we understand the modern system, or in the absence of a modern system, making use of known modern systems. We single out the effect of hydrology on lake records to illustrate the importance of understanding the modern system. The Waubay Lakes Chain in NE South Dakota is a series of lakes at different elevations and spill points that may be hydrologically connected, even coalescing, or may be isolated, though some remain hydrologically open (Niehus et al. 1999). Pickerel is an "upland" open freshwater lake whose level remains nearly constant, while Waubay is a shallow lake at intermediate elevation having more changes in level and salinity. Bitter, at the lowest elevation, receives spillover from Waubay during high water periods, exhibits wide ranges of salinity and elevation including going dry. Pickerel has a short residence time with lower δ18O and TDS than Waubay and Bitter (08/1991: -4.1 permil, -1.5 permil, and -1.8 permil; 204 mg/L, 6,420 mg/L, and 13,128mg/L respectively). The three lakes see the same climate, but their hydrologies lead to these different characteristics that interpreted in climate terms would suggest Pickerel resides under a wet climate while Bitter resides under a dry climate. The sediment records from these lakes though incompletely

  20. Characterization of Lake Michigan coastal lakes using zooplankton assemblages

    USGS Publications Warehouse

    Whitman, Richard L.; Nevers, Meredith B.; Goodrich, Maria L.; Murphy, Paul C.; Davis, Bruce M.

    2004-01-01

    Zooplankton assemblages and water quality were examined bi-weekly from 17 April to 19 October 1998 in 11 northeastern Lake Michigan coastal lakes of similar origin but varied in trophic status and limnological condition. All lakes were within or adjacent to Sleeping Bear Dunes National Lakeshore, Michigan. Zooplankton (principally microcrustaceans and rotifers) from triplicate Wisconsin net (80 I?m) vertical tows taken at each lake's deepest location were analyzed. Oxygen-temperature-pH-specific conductivity profiles and surface water quality were concurrently measured. Bray-Curtis similarity analysis showed small variations among sample replicates but large temporal differences. The potential use of zooplankton communities for environmental lake comparisons was evaluated by means of BIOENV (Primer 5.1) and principal component analyses. Zooplankton analyzed at the lowest identified taxonomic level yielded greatest sensitivity to limnological variation. Taxonomic and ecological aggregations of zooplankton data performed comparably, but less well than the finest taxonomic analysis. Secchi depth, chlorophyll a, and sulfate concentrations combined to give the best correlation with patterns of variation in the zooplankton data set. Principal component analysis of these variables revealed trophic status as the most influential major limnological gradient among the study lakes. Overall, zooplankton abundance was an excellent indicator of variation in trophic status.

  1. Morphological variation of siscowet lake trout in Lake Superior

    USGS Publications Warehouse

    Bronte, C.R.; Moore, S.A.

    2007-01-01

    Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

  2. Evaluation of Lake Modification Alternatives for Lake Sihwa, Korea

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Il; Kim, Byeong-Chan; Oh, Hae-Jin

    2002-01-01

    After the construction of an embankment at the Bay of Sihwa in Korea, a lake of 56.5 km2 surface area and 330 million m3 volume was created. Because of rapid socioenvironmental changes and the lowering of water quality in Lake Sihwa, various external measures have been proposed and some of them are being implemented. In this paper, we examine two alternatives for in-lake modification: one alternative is zoning of the lake by constructing two submerged dams and the other is channeling of the lake through reclamation. Water quality modeling was conducted for both alternatives to assess their effects. Results of the modeling revealed that the reduction of the lake size through two different approaches, when accompanied with other external measures, would improve the water quality, but to different degrees. The zonation is expected to improve the freshwater quality up to the level supplying 45 million m3 of water per year for agricultural use. The quality of channeled water would be inappropriate for agricultural use, but suitable for outdoor activities such as recreation or fishing regardless of reclamation plans considered.

  3. Functional microbiology of soda lakes.

    PubMed

    Sorokin, Dimitry Y; Banciu, Horia L; Muyzer, Gerard

    2015-06-01

    Soda lakes represent unique permanently haloalkaline system. Despite the harsh conditions, they are inhabited by abundant, mostly prokaryotic, microbial communities. This review summarizes results of studies of main functional groups of the soda lake prokaryotes responsible for carbon, nitrogen and sulfur cycling, including oxygenic and anoxygenic phototrophs, aerobic chemolithotrophs, fermenting and respiring anaerobes. The main conclusion from this work is that the soda lakes are very different from other high-salt systems in respect to microbial richness and activity. The reason for this difference is determined by the major physico-chemical features of two dominant salts - NaCl in neutral saline systems and sodium carbonates in soda lakes, that are influencing the amount of energy required for osmotic adaptation.

  4. Lake restoration technology transfer assessment

    SciTech Connect

    Daschbach, M.H.; Roe, E.M.; Sharpe, W.E.

    1982-06-01

    Based upon a review of the eutrophication problem and its impact on lake restoration (LR) programs, treatment of the relatively new problem of acid deposition and its impact on LR activities, consideration of the LR programs of the Environmental Protection Agency and several states, and a review of individual LR technology transfer publications, it is recommended that new LR technology transfer programs be given a low priority until more new information is available on the restoration of acidified lakes. Both primary and secondary users of LR research, technology transfer documents, and public awareness documents were considered in this assessment. Primary users included the general public and recreationists, lakeshore property owners, lake/homeowner associations, lake/sanitary districts, and research and environmental organizations; secondary users included state/county/local officials who administer/manage water-related regulations/activities. 4 tables.

  5. Water Level Fluctuations of Lake Enriquillo and Lake Saumatre in Response to Environmental Changes

    NASA Astrophysics Data System (ADS)

    Poteau, D.; Romero Luna, E. J.; Walter, M. T.; Steenhuis, T. S.

    2011-12-01

    The water levels of Lake Saumatre in Haiti and Lake Enriquillo in the Dominican Republic have been increasing continuously for the past 5-10 years. As result roads and lake shore agriculture are flooded and there is an interest in determining the causes of the continuous lake growth and finding solutions to reverse the trend Various theories haven proposed for growth of the lakes such as climate change and deforestation. Deforestation would affect the hydrological balance by means of changing infiltration rates. To examine the temporal variations in the lake, the lake surface areas during the past 30 years were obtained from available satellite data and converted into volumes. These lake surface areas showed a steady increase starting in 2003 for Lake Saumatre and in 2008 for Lake Enriquillo. Land cover change obtained by means of remote sensing for the years of 1986 and 2010 showed no significant change and could therefore be ruled out as a cause for the lake levels increases. A simple water balance model that had been validated for monsoon climates matched the lake level volumes fluctuations well for the last 30 years including the recent rise in lake levels. Thus the lake level increases could be directly related to the greater precipitation starting some 10 years ago. The difference in starting time of lake level rise between the two lakes could be explained by a larger storage capacity in the a Lake Enriquillo watershed compared to the Lake Saumatre watershed

  6. Spatial variation among lakes within landscapes: Ecological organization along lake chains

    USGS Publications Warehouse

    Soranno, Patricia A.; Webster, Katherine E.; Riera, Joan L.; Kratz, Timothy K.; Baron, Jill S.; Bukaveckas, Paul A.; Kling, George; White, David S.; Caine, Nel; Lathrop, Richard C; Leavitt, Peter R.

    1999-01-01

    Although limnologists have long been interested in regional patterns in lake attributes, only recently have they considered lakes connected and organized across the landscape, rather than as spatially independent entities. Here we explore the spatial organization of lake districts through the concept of landscape position, a concept that considers lakes longitudinally along gradients of geomorphology and hydrology. We analyzed long-term chemical and biological data from nine lake chains (lakes in a series connected through surface or groundwater flow) from seven lake districts of diverse hydrologic and geomorphic settings across North America. Spatial patterns in lake variables driven by landscape position were surprisingly common across lake districts and across a wide range of variables. On the other hand, temporal patterns of lake variables, quantified using synchrony, the degree to which pairs of lakes exhibit similar dynamics through time, related to landscape position only for lake chains with lake water residence times that spanned a wide range and were generally long (close to or greater than 1 year). Highest synchrony of lakes within a lake chain occurred when lakes had short water residence times. Our results from both the spatial and temporal analyses suggest that certain features of the landscape position concept are robust enough to span a wide range of seemingly disparate lake types. The strong spatial patterns observed in this analysis, and some unexplained patterns, suggest the need to further study these scales and to continue to view lake ecosystems spatially, longitudinally, and broadly across the landscape.

  7. Monitoring lake and reservoir restoration: Technical supplement to the lake and reservoir restoration guidance manual

    SciTech Connect

    Wedepohl, R.E.; Knauer, D.R.; Wolbert, G.B.; Olem, H.; Garrison, P.J.

    1990-01-01

    In the manual the lake manager will find practical information on how to design and implement a lake monitoring program during and following a lake restoration project. In addition to describing monitoring methods for both the waterbody and the watershed, the manual deals with monitoring specific in-lake restoration techniques. Although the manual specifically guides the lake manager who must meet the Clean Lakes Program Phase II monitoring requirements, readers will find it helpful as a starting point for more comprehensive studies of lake ecosystems and useful in designing any lake study. Researchers will welcome its recommendations for consistent methods and quality assurance procedures.

  8. Burrowing saves Lake Erie clams

    USGS Publications Warehouse

    Nichols, S. Jerrine; Wilcox, Douglas A.

    1997-01-01

    Freshwater unionid clams in North America have been virtually eliminated from waters that are colonized by zebra mussels. Near total mortality has been reported in western Lake Erie, but we have discovered a large population of native clams in a Lake Erie wetland that shows little sign of infestation. Field observations and laboratory experiments show that warm summer water temperatures and soft, silt-clay sediments trigger burowing by clams. This discourages infestation and physically removes any attached zebra mussels.

  9. Patagonian Lakes, Argentina, South America

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Patagonian Lakes of Argentinas Los Glacieres National Park (50.0S, 73.0W) occupying the foothills of the southern Andes Mountains along the border with Chile, are some of the most scenic in South America. The range is covered by a permanent ice cap and glaciers. Glacier activity frequently reaches into the lake region causing blockage and impounding of the waters until water pressure causes the glacier to crack with a roar that can be heard for miles.

  10. Mitigation alternatives for L Lake

    SciTech Connect

    Moore, D.B.

    1988-11-03

    The current condition of L Lake/Steel Creek was summarized in a report to SCDHEC in June 1988 which reported that the L Lake and Steel Creek ecosystems were adequately developing towards balanced biological communities. If mitigation for L Lake inputs, specifically temperature and nutrients, are required, several viable alternatives are available. A report prepared by Spencer in 1986 discusses the various options available for cooling L-Reactor discharges. In effect, a small cooling tower is the only realistic solution to reducing effluent temperatures. Nutrient mitigation can take several approaches including upstream sewage treatment, hypolimnetic withdrawal, dilution of input water by Par Pond water, precipitation of nutrients, and sediment oxidation. None of these systems would influence the thermal regime, but would significantly reduce nutrient input into the system. One beneficial use of L-Lake thermal effluents is algaculture, the production of useful algae. A document prepared in 1988 concludes that algaculture is a technically and economically feasible mitigation alternative for L Lake and could allow L Lake to be handled under Section 318 of the Clean Water Act.

  11. The Global Climatology of Large Lakes

    NASA Astrophysics Data System (ADS)

    Merchant, Christopher J.; MacCallum, Stuart N.

    2010-12-01

    There are ~250 large lakes in the world, large here meaning lakes with surface areas exceeding 500 km2 . Lakes are potentially sensitive indicators of regional climatic changes and large lakes also significantly modulate climate locally, via their effects on surface atmosphere fluxes and atmospheric stability. The interactions of lakes and atmosphere are therefore significant for climatology and weather forecasting. Relatively few lakes are permanently instrumented (mostly in N America and Europe), and in assimilation systems for numerical weather prediction, highly simplistic approximations for lake surface temperature are giving way to lake temperature models within the land-atmosphere exchange schemes. It is therefore important to exploit satellite observations to inform and constrain lake and weather models, and to provide observations of lake temperature changes for a wider range of lakes. Here we present results from the first phase of an ESA-funded project, ARCLake, to demonstrate accurate lake surface temperatures and detection of ice cover, using ATSR-2 and AATSR, for large lakes globally. It is sometimes assumed that sea surface temperature (SST) techniques are applicable, but in fact, lake-specific approaches are required for cloud detection and for temperature retrieval. In this paper, we present preliminary results from application of the techniques described in a companion paper [1].

  12. Proglacial lakes: character, behaviour and geological importance

    NASA Astrophysics Data System (ADS)

    Carrivick, Jonathan L.; Tweed, Fiona S.

    2013-10-01

    Proglacial lakes are ubiquitous within the Quaternary record and can provide exceptional breadth and depth of palaeoenvironmental information. Present deglaciation is increasing the number and size of proglacial lakes around the world. This study provides a synthesis of knowledge on proglacial lake character and behaviour and critically evaluates the importance of proglacial lakes from a geological perspective. We show how ‘ice-marginal' or ‘ice-contact' lakes and other distal proglacial lakes can be distinguished from each other by geomorphological, sedimentological, chemical and biological characteristics. The key controls on proglacial lake geomorphology and sedimentology are outlined and discussed. Proglacial lakes can exacerbate mountain glacier and ice sheet margin ablation via mechanical and thermal stresses, but very large lakes can moderate summer air temperatures and relatively retard summer ice ablation. Proglacial lakes interrupt meltwater flux and are very efficient sediment traps. Hydrological routing and consequent geomorphological activity can be radically modified by sudden drainage of proglacial lakes and resultant glacial lake outburst floods; exceptionally large proglacial lake drainages affected global ocean circulation and global climate during the Quaternary. Overall, analyses of proglacial lakes can provide a valuable insight into (i) patterns, character and behaviour of mountain glaciers, ice sheets and glaciations, and (ii) the impacts of past, present and future deglaciation.

  13. The size-distribution of Earth's lakes.

    PubMed

    Cael, B B; Seekell, D A

    2016-01-01

    Globally, there are millions of small lakes, but a small number of large lakes. Most key ecosystem patterns and processes scale with lake size, thus this asymmetry between area and abundance is a fundamental constraint on broad-scale patterns in lake ecology. Nonetheless, descriptions of lake size-distributions are scarce and empirical distributions are rarely evaluated relative to theoretical predictions. Here we develop expectations for Earth's lake area-distribution based on percolation theory and evaluate these expectations with data from a global lake census. Lake surface areas ≥8.5 km(2) are power-law distributed with a tail exponent (τ = 1.97) and fractal dimension (d = 1.38), similar to theoretical expectations (τ = 2.05; d = 4/3). Lakes <8.5 km(2) are not power-law distributed. An independently developed regional lake census exhibits a similar transition and consistency with theoretical predictions. Small lakes deviate from the power-law distribution because smaller lakes are more susceptible to dynamical change and topographic behavior at sub-kilometer scales is not self-similar. Our results provide a robust characterization and theoretical explanation for the lake size-abundance relationship, and form a fundamental basis for understanding and predicting patterns in lake ecology at broad scales. PMID:27388607

  14. Digital geologic map of the Thirsty Canyon NW quadrangle, Nye County, Nevada

    USGS Publications Warehouse

    Minor, S.A.; Orkild, P.P.; Sargent, K.A.; Warren, R.G.; Sawyer, D.A.; Workman, J.B.

    1998-01-01

    This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern Nevada. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic and tectonic interest. The Thirsty Canyon NW quadrangle is located in southern Nye County about 20 km west of the Nevada Test Site (NTS) and 30 km north of the town of Beatty. The map area is underlain by extensive layers of Neogene (about 14 to 4.5 million years old [Ma]) mafic and silicic volcanic rocks that are temporally and spatially associated with transtensional tectonic deformation. Mapped volcanic features include part of a late Miocene (about 9.2 Ma) collapse caldera, a Pliocene (about 4.5 Ma) shield volcano, and two Pleistocene (about 0.3 Ma) cinder cones. Also documented are numerous normal, oblique-slip, and strike-slip faults that reflect regional transtensional deformation along the southern part of the Walker Lane belt. The Thirsty Canyon NW map provides new geologic information for modeling groundwater flow paths that may enter the map area from underground nuclear testing areas located in the NTS about 25 km to the east. The geologic map database comprises six component ArcINFO map coverages that can be accessed after decompressing and unbundling the data archive file (tcnw.tar.gz). These six coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt) are formatted here in ArcINFO EXPORT format. Bundled with this database are two PDF files for readily viewing and printing the map, accessory graphics, and a description of map units and compilation methods.

  15. Crust-mantle accommodation of Africa-Eurasia convergence in the NW-Moroccan margin

    NASA Astrophysics Data System (ADS)

    Zlotnik, S.; Jimenez-Munt, I.; Fernandez, M.

    2011-12-01

    Recent studies carried out in NW-Africa indicate prominent variations of the lithosphere-asthenosphere boundary (LAB) depth. The studies combine gravity, geoid, surface heat flow, elevation and seismic data along a profile running from the Tagus Abyssal Plain to the Sahara Platform and crossing the Gorringe Bank, the NW Moroccan Margin and the Atlas Mountains. The resulting mantle density anomalies show a prominent lithospheric mantle thickening beneath the margin (LAB >200 km-depth) followed by thinning beneath the Atlas Mountains (LAB ~90 km-depth). A combination of mantle underthrusting due to oblique convergence together with a viscous dripping fed by lateral mantle dragging can explain the imaged lithospheric structure. The model is consistent with a strong decoupled crustal-mantle mechanical response to the Africa-Eurasia convergence and results in positive/negative dynamic topography in regions with thickened/thinned crust. In this work we go a step further analysing, by means of dynamic numerical simulations, the viscous dragging and the Rayleigh-Taylor-like process. Our goal is to understand the initial lithospheric mantle structure suitable to produce the inferred dynamic process. In addition, we study the key factors controlling the deformation of the lithospheric mantle when submitted to convergence. Using the numerical framework Underworld to carry out the simulations we found the key factors controlling the process. Chief among these factors are lithospheric/mantle viscosity ratio and initial mantle and crustal structure. Nevertheless, the process is not very sensitive to the usual power law parameters for mantle rocks (activation energy and volume, power law exponent, etc.), indicating the importance of the rheology of the upper half of the lithosphere, where the power law is not active. These results allow us to speculate on the past and future evolution of the NW-Moroccan margin which could show the appropriated conditions for subduction initiation.

  16. INTERSECTION OF 445 NORTH & 1040 EAST, SALT LAKE CITY, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERSECTION OF 445 NORTH & 1040 EAST, SALT LAKE CITY, UT. VIEW LOOKING SOUTH. REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 18272, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  17. 200 MAIN STREET, SALT LAKE CITY, UT. VIEW LOOKING EAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    200 MAIN STREET, SALT LAKE CITY, UT. VIEW LOOKING EAST OF "MAIN' STREET. REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 18273, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  18. Survival of lake trout eggs and fry reared in water from the upper Great Lakes

    USGS Publications Warehouse

    Mac, Michael J.; Edsall, Carol Cotant; Seelye, James G.

    1985-01-01

    As part of continuing studies of the reproductive failure of lake trout (Salvelinus namaycush) in Lake Michigan, we measured the survival of lake trout eggs and fry of different origins and reared in different environments. Eggs and milt were stripped from spawning lake trout collected in the fall of 1980 from southeastern Lake Michigan, northwestern Lake Huron, south central Lake Superior, and from hatchery brood stock. Eggs from all sources were incubated, and the newly hatched fry were reared for 139 days in lake water from each of the three upper Great Lakes and in well water. Survival of eggs to hatching at all sites was lowest for those from Lake Michigan (70% of fertilized eggs) and highest for eggs from Lake Superior (96%). Comparisons of incubation water from the different lakes indicated that hatching success of eggs from all sources was highest in Lake Huron water, and lowest in Lake Michigan water. The most notable finding was the nearly total mortality of fry from eggs of southeastern Lake Michigan lake trout. At all sites, the mean survival of Lake Michigan fry through 139 days after hatching was only 4% compared to near 50% for fry from the other three sources. In a comparison of the rearing sites, little influence of water quality on fry survival was found. Thus, the poor survival was associated with the source of eggs and sperm, not the water in which the fry were reared.

  19. Direct Observations of Explosive Eruptive Activity at a Submarine Volcano, NW Rota-1, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Deardorff, N.; Matsumoto, H.; Cashman, K. V.; Dziak, R. P.; Merle, S. G.

    2006-12-01

    In April 2006, a series of extraordinary observations of a deep-sea volcanic eruption were made at NW Rota-1, located at 14^{circ}36'N in the Mariana arc, western Pacific. This is a conical, basaltic-andesite submarine volcano with a summit depth of 517 m. Explosive eruptive activity at NW Rota-1 was discovered in 2004 and was witnessed again in 2005, but the activity in 2006 was especially vigorous and well documented. During six dives with the remotely operated vehicle Jason II over a period of 7 days, video observations made at close range documented a diverse and increasingly energetic range of volcanic activity that culminated in explosive bursts with flashes of glowing red lava propelled by violently expanding gases. Other notable activity included discreet degassing events, extrusion of sluggish lava flows, explosions that formed dilute density currents and/or expelled rocks and ash tens of meters from the vent, and rapid pressure oscillations apparently caused by the repeated formation and condensation of steam. During the last dive when the highest extrusion rates were observed, quasi-periodic bursts from the vent, each lasting 1-10 minutes, were separated by pauses lasting 10 seconds to a few minutes. Each burst started as a plug of crusted-over lava rose in the vent and was blown apart by expanding gases, producing large lava bombs with distinctly flat, disc-like shapes. A remarkable aspect of these observations was how close Jason II could be to the vent during the eruptions. This was because the pressure of the overlying seawater dampened the energy of the explosions and slowed the velocity of volcanic ejecta. Also, lava degassing could be visualized with great clarity underwater as either clear bubbles (CO2) or opaque yellow clouds (dominated by SO2 and H2S). A portable hydrophone with a 30-hour recording capacity was deployed twice by Jason II at the summit of NW Rota-1 during the 2006 dive series. The hydrophone data extends the visual observations

  20. Outer synchronization investigation between WS and NW small-world networks with different node numbers

    NASA Astrophysics Data System (ADS)

    Zhou, Guangye; Li, Chengren; Li, Tingting; Yang, Yi; Wang, Chen; He, Fangjun; Sun, Jingchang

    2016-09-01

    Some typical dual-ring erbium-doped fiber lasers with hyperchaos behaviors are taken as nodes to construct two kinds of small-world networks-NW and WS networks. Based on Lyapunov stability theorem, the appropriate controllers are designed and the outer synchronization between the small-world networks with diverse structures and different node numbers is further investigated. The simulation results show that the perfect synchronization between the complex small-world networks is realized, which is of potential application for all optical communication network.

  1. The Neo-Tethyan subduction zone(s,?) in Azerbaijan, NW Iran: preliminary results

    NASA Astrophysics Data System (ADS)

    Lechmann, Anna; Burg, Jean-Pierre; Faridi, Mohammad

    2015-04-01

    Azerbaijan in NW Iran, and in particular the Khoy ophiolitic complex, require more detailed documentation to integrate them as elements of the Alpine-Himalayan orogenic belt. They are attributed to multiple accretion and collision after subduction and closure of the Tethys Ocean and related seaways. We are interested in the pre- to syn-collisional relationships between the ophiolitic, arc and other magmatic units. This work investigates to what extent single or multiple collisions and orogeny have shaped the NW Iranian Plateau. In particular, we want to understand the changes in deformation style within the collision zone and the effects of several possibly coeval events such as closure of two suture zones separated by an arc and possibly followed by slab break-off(s). Fieldwork focused on sampling the different magmatic rock units to specify the structural record and the structural relationships between the various lithological units. Cretaceous to Quaternary, regionally distributed magmatic rocks were collected to have good resolution of their changes in space and time. Petrological, geochemical and isotope studies will characterize magmatic rocks and their sources. Major and trace element geochemistry of mantle and crustal suites of the Khoy ophiolitic complex help to constrain the tectonic setting. Two complexes were defined on the basis of K-Ar dating (Khalatbari-Jafari et al., 2004). An older, probably subducted ophiolite of Triassic-Jurassic age and a younger non-metamorphic ophiolite of Late Cretaceous age. Fossil-bearing sediments provide stratigraphic ages of important contacts. Preliminary results are present in form of bulk rock and trace element chemistry of ultramafic and mafic rocks of the Khoy ophiolite(s, ?) and offer a first possibility to compare the data with already existing publications. Additionally, petrological studies of various magmatic rocks present first products for a starting discussion on the geodynamic evolution of the NW part of

  2. Pollen loads of eucalypt and other pollen types in birds in NW Spain.

    PubMed

    Calviño-Cancela, María; Neumann, Max

    2015-12-01

    Here we present the amount of pollen of eucalypt and pollen of other types for birds captured in two bird ringing stations for 14 months (March 2014 to April 2015) in NW Spain. Common and latin names of all birds species captured, together with the number of captured individuals (N), prevalence of eucalypt pollen (percentage of individuals with eucalypt pollen) and of pollen of other types and average pollen loads per individual for eucalypt and other pollen types is presented. See [1] for further information and discussion.

  3. Three new species of Pruvotinidae (Mollusca: Solenogastres) from Antarctica and NW Spain

    NASA Astrophysics Data System (ADS)

    Zamarro, Maria; García-Álvarez, Oscar; Urgorri, Victoriano

    2013-09-01

    The family Pruvotinidae (Solenogastres, Cavibelonia) includes thirty species of fifteen genera grouped in five subfamilies. These subfamilies are defined by the combination of the presence or absence of hollow hook-shaped sclerites, the presence or absence of a dorsopharyngeal gland and the type of ventrolateral foregut glandular organs: type A, type C or circumpharyngeal. In this paper, three new species of the family Pruvotinidae are described: Pruvotina artabra n. sp. and Gephyroherpia impar n. sp. from NW Spain, and Pruvotina manifesta n. sp. from Antarctic Peninsula. These new descriptions increase the global knowledge of Solenogastres biodiversity.

  4. Atmospheric-Pressure Processed Silver Nanowire (Ag-NW)/ZnO Composite Transparent Conducting Contacts

    SciTech Connect

    Perkins, John D.; Aggarwal, Shruti; van Hest, Maikel F. A. M.; Ginley, David S.

    2015-06-14

    Composite transparent contacts (TCs) based on metal nanowires and metal oxide matrix materials hold great promise for high performance transparent contacts for photovoltaics and opto-electronic technologies with the potential of all-atmospheric pressure processing. The metal nanowire mesh can provide both electrical conductivity and mechanical robustness against bending while the matrix material can both control the electrical interface and protect the metal nanowires. Here, we demonstrate all atmospheric pressure processed Ag-NW/ZnO composite TCs that are 90% transparent in the visible with sheet resistance Rs ~= 10 Ohms/sq. In addition, the composite TCs have higher infrared transmission than conventional TCO films with the same sheet resistance.

  5. Lake Level Coherence Supports Common Driver

    NASA Astrophysics Data System (ADS)

    Stow, Craig A.; Lamon, E. C.; Kratz, T. K.; Sellinger, C. E.

    2008-10-01

    Lake Superior, the world's largest lake by surface area (82,400 square kilometers), experienced record low water levels in 2007 [Holden, 2007]. In addition, lakes Michigan and Huron (58,000 and 59,596 square kilometers, respectively), which behave hydraulically as one lake and which began declining in 1997, were at near-record low levels in 2007 [Sellinger et al., 2008]. The low levels that these three lakes are experiencing have raised concern that the Laurentian Great Lakes are beginning to realize predicted climate change effects [Magnuson et al., 1997].

  6. Lake water quality mapping from LANDSAT

    NASA Technical Reports Server (NTRS)

    Scherz, J. P.

    1977-01-01

    The lakes in three LANDSAT scenes were mapped by the Bendix MDAS multispectral analysis system. Field checking the maps by three separate individuals revealed approximately 90-95% correct classification for the lake categories selected. Variations between observers was about 5%. From the MDAS color coded maps the lake with the worst algae problem was easily located. This lake was closely checked and a pollution source of 100 cows was found in the springs which fed this lake. The theory, lab work and field work which made it possible for this demonstration project to be a practical lake classification procedure are presented.

  7. Lake water quality mapping from Landsat

    NASA Technical Reports Server (NTRS)

    Scherz, J. P.

    1977-01-01

    In the project described remote sensing was used to check the quality of lake waters. The lakes of three Landsat scenes were mapped with the Bendix MDAS multispectral analysis system. From the MDAS color coded maps, the lake with the worst algae problem was easily located. The lake was closely checked, and the presence of 100 cows in the springs which fed the lake could be identified as the pollution source. The laboratory and field work involved in the lake classification project is described.

  8. Hydrogeology of the Lake Miona area, northeast Sumter County, Florida

    USGS Publications Warehouse

    Bradner, L.A.

    1986-01-01

    The Lake Miona area, in northeast Sumter County, is characterized by karstic depressions that contain lakes, ponds, and marshes that drain vertically to the upper Floridan aquifer. Lake Miona, Black Lake, and Cherry Lake are the prominent water features of the area. When the lake levels are lowest, the lakes are not connected, but at higher levels, they become connected and water flows eastward from Lake Miona through Black Lake to Cherry Lake. The chemical and biological conditions in the lakes are such that, although they support a large population of submerged aquatic plants, no problem with algae blooms was observed. (USGS)

  9. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This simulated natural color image presents a late spring view of north central Utah that includes all of the Olympic sites. The image extends from Ogden in the north, to Provo in the south; and includes the snow-capped Wasatch Mountains and the eastern part of the Great Salt Lake.

    This image was acquired on May 28, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution

  10. Dongting Lake, China

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images show dramatic change in the water at Dongting Lake in Hunan province, China. A flood crest surged down the Yangtze River in late August of this year, but the embankments made by residents there held. The left image was acquired on September 2, 2002 and shows the extent of the lake. The right image was obtained March 19, 2002 before the flooding began.

    These images were acquired on September 2, 2002 and March 19,2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as

  11. Hydrology of Central Florida Lakes - A Primer

    USGS Publications Warehouse

    Schiffer, Donna M.

    1998-01-01

    INTRODUCTION Lakes are among the most valued natural resources of central Florida. The landscape of central Florida is riddled with lakeswhen viewed from the air, it almost seems there is more water than land. Florida has more naturally formed lakes than other southeastern States, where many lakes are created by building dams across streams. The abundance of lakes on the Florida peninsula is a result of the geology and geologic history of the State. An estimated 7,800 lakes in Florida are greater than 1 acre in surface area. Of these, 35 percent are located in just four counties (fig. 1): Lake, Orange, Osceola, and Polk (Hughes, 1974b). Lakes add to the aesthetic and commercial value of the area and are used by many residents and visitors for fishing, boating, swimming, and other types of outdoor recreation. Lakes also are used for other purposes such as irrigation, flood control, water supply, and navigation. Residents and visitors commonly ask questions such as Whyare there so many lakes here?, Why is my lake drying up (or flooding)?, or Is my lake spring-fed? These questions indicate that the basic hydrology of lakes and the interaction of lakes with ground water and surface water are not well understood by the general population. Because of the importance of lakes to residents of central Florida and the many questions and misconceptions about lakes, this primer was prepared by the U.S. Geological Survey (USGS) in cooperation with the St. Johns River Water Management District and the South Florida Water Management District. The USGS has been collecting hydrologic data in central Florida since the 1920s, obtaining valuable information that has been used to better understand the hydrology of the water resources of central Florida, including lakes. In addition to data collection, as of 1994, the USGS had published 66 reports and maps on central Florida lakes (Garcia and Hoy, 1995). The main purpose of this primer is to describe the hydrology of lakes in central

  12. Lake isotope variability in the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Yuan, F.; Sheng, Y.; Yao, T.; Li, J.

    2010-12-01

    The use of isotopic ratios of meteoric waters has increased rapidly in recent studies of moisture sources, trajectories and other climatic processes over the Tibetan Plateau. However, measurements of δ18O and δD of lake water are scarce. Little is known of isotopic processes in Tibetan lakes. Here we present results from 27 lakes across the plateau. The isotopic results show that the Tibetan lake water line deviates considerably from the regional and global meteoric water lines (Fig. 1). Although many lakes in the plateau have expanded over the last several decades as shown by archived satellite images and reduction in lake salinity, most of the lakes including some freshwater lakes contain water with negative values of d-excess (d). Moreover, there is a negative correlation between d and total dissolved solids (Fig. 2). This study suggests that evaporation has played an important role in regulating water chemical and isotopic compositions of high-altitude lakes in the plateau. Figure 1. Relationship of δ18O and δD in surface waters from open lakes (i.e., lakes with outlets) (open circles) and closed-basin lakes (filled circles) in the Tibetan Plateau. Figure 2. Correlation of deuterium excess (d) and TDS in surface waters from Tibetan lakes.

  13. Eutrophication of the St. Lawrence Great Lakes

    USGS Publications Warehouse

    Beeton, Alfred M.

    1965-01-01

    Lakes Huron, Michigan, and Superior are classified as oligotrophic lakes on the basis of their biological, chemical, and physical characteristics. Lake Ontario, although rich in nutrients, is morphometrically oligotrophic or mesotrophic because of its large area of deep water. Lake Erie, the most productive of the lakes and the shallowest, is eutrophic. Several changes commonly associated with eutrophication in small lakes have been observed in the Great Lakes. These changes apparently reflect accelerated eutrophication in the Great Lakes due to man's activity. Chemical data compiled from a number of sources, dating as early as 1854, indicate a progressive increase in the concentrations of various major ions and total dissolved solids in all of the lakes except Lake Superior. The plankton has changed somewhat in Lake Michigan and the plankton, benthos, and fish populations of Lake Erie are greatly different today from those of the past. An extensive area of hypolimnetic water of Lake Erie has developed low dissolved oxygen concentrations in late summer within recent years.

  14. Lake Naivasha, Kenya

    NASA Technical Reports Server (NTRS)

    2008-01-01

    If you live in Europe and buy roses, there is a good chance that they were grown in Kenya specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Some 25% of Europe's cut flowers come from Kenya. After a tentative start in the 1980s the industry is now the country's third-largest foreign-currency earner, bringing in $120m a year. But the recent violence in Kenya is having a major impact on the flower growers. A local trade union says 3,000 of the 30,000 workers employed in Naivasha's flower farms have abandoned their jobs. Kenya emerged as a flower power when Israel scaled down its own industry. It has since lost business to neighboring Ethiopia, which offers tax breaks and better security, but Naivasha's perfect intensity of sunlight and days of near-constant length should keep it on top.

    The ASTER image was acquired February 2, 2008, covers an area of 25 x 26.6 km, and is located near 0.8 degrees south latitude, 36.4 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. 1. GENERAL VIEW OF THE LOWER END OF TWIN LAKES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW OF THE LOWER END OF TWIN LAKES SHOWING THE HISTORIC OUTLET WORKS AT THE EDGE OF THE WATER NEAR CENTER OF THE PHOTO WITH THE NEW TWIN LAKES DAM JUST BEHIND. VIEW LOOKING SOUTHEAST. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  16. Lake and reservoir restoration guidance manual: first edition

    SciTech Connect

    Moore, L.; Thornton, K.

    1988-02-01

    This manual provides guidance to lake managers, homeowners, lake associations, and laypersons on lake and reservoir restoration, management and protection. It also provides information on how to identify lake problems, evaluate practices for restoring and protection lakes, watershed management, and creating a lake-management plan.

  17. Large floods and rapid deglaciation of the Lake Michigan Lobe and environs, ca. 19 to 18 ka

    NASA Astrophysics Data System (ADS)

    Curry, B.; Brown, S.; Hajic, E.; Konen, M.

    2007-12-01

    Our collective research indicates that features attributed to large floods are associated with events separated in time by about 900 years. The oldest event is interpreted from a long and narrow morainal gap floored by coarse sand and gravel outwash that likely formed by a plungepool and migration of this nickpoint via overflow of Glacial Lake Wauponsee across the Marseilles Moraine near Oswego, Illinois. The weighted mean of four AMS C-14 ages of tundra plant stems and leaves identified from the base of the overlying lake fill is 18,900 ± 35 cal yr BP (15,710 ± 35 yr BP). The age of another overflow channel across the Marseilles Moraine is not yet known, but similar channel floor elevations relative to the Oswego channel suggest that they were contemporaneous. Landforms attributed to a younger large flood are located downstream of where the Fox River breaches the Woodstock Moraine in Algonquin, Illinois. Radiocarbon ages of tundra plant fossils preserved in sediment of ice-walled and slackwater lakes associated with the Woodstock and West Chicago Moraines indicate the younger floods likely predate 18,080 cal yr BP (14,860 ± 40 yr BP; UCIAMS-26265). A statistically similar age of 18,000 cal yr BP (14,830 ± 50 yr BP; B-207031) was obtained from organics preserved in a slackwater lake deposit in the Illinois River valley near Havana. The slackwater lake basin is floored by coarse gravelly sand attributed to the latest stage of flooding. At this time, the similar C-14 ages are the only evidence that link the proglacial and distal sites (more than 150 km apart) to the same flood. Based on continuity of morainic ridges, we believe that the large floods that eroded scarps into the southern margin of the Valparaiso Moraine north and parallel to the Kankakee River in NW Indiana and NE Illinois are contemporaneous with the younger large floods discussed above. The scarp was eroded by meltwater from interlobate areas of the Lake Michigan and Huron-Erie Lobes. The rate of

  18. Barnacles Tell no Lies - Bioclastic deposits and in-situ balanid colonies delineate shorelines of the Holocene palaeolake at Tayma (NW Saudi Arabia)

    NASA Astrophysics Data System (ADS)

    Engel, Max; Frenzel, Peter; Pint, Anna; Dinies, Michèle; Gleixner, Gerd; Hoelzmann, Philipp; Neugebauer, Ina; Plessen, Birgit; Brückner, Helmut

    2016-04-01

    radiocarbon data from the thickest bioclastic shoreline deposit (Engel et al. 2012) and corrections for hardwater effects, the formation of the highest shoreline overlaps with the most humid phase of maximum grassland expansion at around 8600-8000 cal BP inferred from the pollen record of sediments inside the sabkha basin (Dinies et al. 2015). During that time, the lake had a perennial regime, brackish to seasonally even hypersaline conditions, a depth of up to 17 m and a minimum area of 22 km², thus testifying to the profound impact the early to mid-Holocene humid phase had on vegetation, hydrography, and sedimentary environs of NW Arabia. Dinies, M., Plessen, B., Neef, R., and Kürschner, H.: When the desert was green: Grassland expansion during the early Holocene in northwestern Arabia. Quatern. Int., 382, 293-302, 2015. Engel, M, Brückner, H., Pint, A., Wellbrock, K., Ginau, A., Voss, P., Grottker, M., Klasen, N., and Frenzel, P.: The early Holocene humid period in NW Saudi Arabia - sediments, microfossils and palaeohydrological modelling. Quatern. Int., 266, 131-141, 2012. Enzel, Y., Kushnir, Y., and Quade, J.: The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons. Global Planet. Change, 129, 69-91, 2015.

  19. Photocurrent enhancement of SiNW-FETs by integrating protein-shelled CdSe quantum dots.

    PubMed

    Moh, Sang Hyun; Kulkarni, Atul; San, Boi Hoa; Lee, Jeong Hun; Kim, Doyoun; Park, Kwang Su; Lee, Min Ho; Kim, Taesung; Kim, Kyeong Kyu

    2016-01-28

    We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 10(6), the highest value compared to other SiNW-based devices in the visible light range. PMID:26755346

  20. Estimate of net trophic transfer efficiency of PCBs to Lake Michigan lake trout from their prey

    USGS Publications Warehouse

    Madenjian, Charles P.; Hesselberg, Robert J.; DeSorcie, Timothy J.; Schmidt, Larry J.; Stedman, Ralph M.; Quintal, Richard T.; Begnoche, Linda J.; Passino-Reader, Dora R.

    1998-01-01

    Most of the polychlorinated biphenyl (PCB) body burden accumulated by lake trout (Salvelinus namaycush) from the Laurentian Great Lakes is from their food. We used diet information, PCB determinations in both lake trout and their prey, and bioenergetics modeling to estimate the efficiency with which Lake Michigan lake trout retain PCBs from their food. Our estimates were the most reliable estimates to date because (a) the lake trout and prey fish sampled during our study were all from the same vicinity of the lake, (b) detailed measurements were made on the PCB concentrations of both lake trout and prey fish over wide ranges in fish size, and (c) lake trout diet was analyzed in detail over a wide range of lake trout size. Our estimates of net trophic transfer efficiency of PCBs to lake trout from their prey averaged from 0.73 to 0.89 for lake trout between the ages of 5 and 10 years old. There was no evidence of an upward or downward trend in our estimates of net trophic transfer efficiency for lake trout between the ages of 5 and 10 years old, and therefore this efficiency appeared to be constant over the duration of the lake trout's adult life in the lake. On the basis of our estimtes, lake trout retained 80% of the PCBs that are contained within their food.

  1. Exploring trends, causes, and consequences of declining lipids in Lake Superior lake trout

    EPA Science Inventory

    The ability of lake trout to forage in deepwater habitats is facilitated by high lipid content, which affords buoyancy. In Lake Superior, lean lake trout historically occupied depths < 80 m, and siscowet lake trout occupied depths > 80 m. Siscowets have been known f...

  2. 78 FR 24228 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final Comprehensive Conservation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... review and comment following the announcement in the Federal Register on October 29, 2012 ] (77 FR 65574... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final... Complex (Complex), which includes Lake Andes NWR, Karl E. Mundt NWR, and Lake Andes Wetland...

  3. 77 FR 65574 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Draft Comprehensive Conservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-29

    ... Complex. We started this process through a notice in the Federal Register (72 FR 27328; May, 15, 2007... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Draft... assessment (EA) for the Lake Andes National Wildlife Refuge Complex (Complex), which includes Lake Andes...

  4. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    USGS Publications Warehouse

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  5. What can the National Lake Assessment Tell Us about Ecosystem Service Benefits in Lakes

    EPA Science Inventory

    The condition of lakes, ponds, and reservoirs is often viewed as existing along a continuum from pristine to impacted. The 2007 National Lake Survey was conducted to assess the condition of the nation’s lakes. Over 1,000 lakes were surveyed and detailed physical and chemical da...

  6. Competition between larval lake herring (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) for zooplankton

    USGS Publications Warehouse

    Davis, Bruce M.; Todd, Thomas N.

    1998-01-01

    Diet and growth of larval lake herring (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) were compared in mesocosm experiments in a small mesotrophic lake in southeastern Michigan. Fish were sampled from single-species and mixed assemblages in 2-m3 cages for 8 weeks during April and May. Both species initially ate mostly cyclopoid copepodites and small cladocerans (Bosmia spp.). Schoener's index of diet overlap showed considerable overlap (70-90%). Lake whitefish ate Daphnia spp. and adult copepods about 2 weeks earlier than did lake herring, perhaps related to their larger mean mouth gape. Lake whitefish were consistently larger than lake herring until the eighth week, especially in the sympatric treatments. Lake whitefish appeared to have a negative effect on the growth of lake herring, as lake herring in mixed-species treatments were smaller and weighed less than lake herring reared in single-species treatments. The diet similarities of lake whitefish and lake herring larvae could make them competitors for food in the Great Lakes. The greater initial size of lake whitefish could allow them to eat larger prey earlier and thereby limit availability of these prey to lake herring at a crucial period of development.

  7. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lake Mohave and Lake Mead, Nevada... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore and... the launching ramp, as established by the Superintendent, Lake Mead Recreation Area:...

  8. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lake Mohave and Lake Mead, Nevada... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore and... the launching ramp, as established by the Superintendent, Lake Mead Recreation Area:...

  9. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lake Mohave and Lake Mead, Nevada... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore and... the launching ramp, as established by the Superintendent, Lake Mead Recreation Area:...

  10. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lake Mohave and Lake Mead, Nevada... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore and... the launching ramp, as established by the Superintendent, Lake Mead Recreation Area:...

  11. 33 CFR 110.127 - Lake Mohave and Lake Mead, Nevada and Arizona.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lake Mohave and Lake Mead, Nevada... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore and... the launching ramp, as established by the Superintendent, Lake Mead Recreation Area:...

  12. Is global change a real threat for conservation of the NW Mediterranean marine biodiversity?

    NASA Astrophysics Data System (ADS)

    Garrabou, J.; Dimar Team

    2003-04-01

    An increasing body of evidence is demonstrating that global change is already affecting terrestrial and marine ecosystems. Coastal marine habitats are a main subject of attention because they harbour a high biological diversity, are among the most productive systems of the world and present high anthropogenic interaction levels. Most studies on the effects of global change on marine ecosystems have focused on tropical habitats but effects on marine habitats at higher latitudes have been increasingly reported during the last decades. We examined the case of the NW Mediterranean sublittoral habitats for which a warming trend in water temperature has already been detected. The actual and potential responses of different taxonomic groups have been examined. We found a clear trend in northward range shifts for a number of species and an increase in disease and mass mortalities events during the last two decades. Therefore, significant modifications of diversity are expected in the next decades in the NW Mediterranean (at least at local scale), through species' immigrations, extinctions or shifts, and potential subsequent cascade effects. These modifications could ultimately disrupt ecosystem functions. Since the Mediterranean, with only 0.82 % of oceans' surface, harbours 4 to 18 % of total marine biodiversity, potential effects of global change in this area could have dramatic consequences for the conservation of the marine diversity, world-wide.

  13. Paleomagnetic investigation of the Early Permian Panjal Traps of NW India; regional tectonic implications

    NASA Astrophysics Data System (ADS)

    Stojanovic, Denis; Aitchison, Jonathan C.; Ali, Jason R.; Ahmad, Talat; Dar, Reyaz Ahmad

    2016-01-01

    The ∼289 Ma Panjal Traps of NW India (Kashmir) are part of a series of rift-related mafic suites (Abor, Sikkim etc.) that were erupted onto northern India (present-day coordinates) around the same time as separation of the Cimmerian blocks of Qiangtang and Sibumasu. We report new data from only the second paleomagnetic investigation of this unit. Standard alternating field and thermal demagnetization methods were used to isolate characteristic magnetizations from seven outcrops at three locations within the Kashmir Valley, NW India. Analysis of four sections (14 individual cooling units) from close to Srinagar, that together form a tectonically coherent sequence spanning ∼3 km of stratigraphy, yield a single-component, primary magnetization with a mean direction of Dec: 134.8°, Inc: 55.3° (α95 = 8.9°, k = 21.0). An inclination-only mean of 52.5° (α95 = 8.9°, k = 47.2) gives a paleolatitude of ∼33°S (±5°). A paleopole of 110.5°E 8.4°S (A95 = 10.7) is also calculated. Assuming the magnetization records a portion of the reverse polarity Kiaman Superchron, the new result indicates extrusion of the Panjal Traps basalts at mid-latitudes in the southern hemisphere. By inference this constrains the location of central Gondwana, and informs debates related to Cimmeria's detachment from Gondwana.

  14. A mid-Holocene candidate tsunami deposit from the NW Cape (Western Australia)

    NASA Astrophysics Data System (ADS)

    May, Simon Matthias; Falvard, Simon; Norpoth, Maike; Pint, Anna; Brill, Dominik; Engel, Max; Scheffers, Anja; Dierick, Manuel; Paris, Raphaël; Squire, Peter; Brückner, Helmut

    2016-03-01

    Although extreme-wave events are frequent along the northwestern coast of Western Australia and tsunamis in 1994 and 2006 induced considerable coastal flooding locally, robust stratigraphical evidence of prehistoric tropical cyclones and tsunamis from this area is lacking. Based on the analyses of X-ray computed microtomography (μCT) of oriented sediment cores, multi-proxy sediment and microfaunal analyses, optically stimulated luminescence (OSL) and 14C-AMS dating, this study presents detailed investigations on an allochthonous sand layer of marine origin found in a back-barrier depression on the NW Cape Range peninsula. The event layer consists of material from the adjacent beach and dune, fines and thins inland, and was traced up to ~ 400 m onshore. Although a cyclone-induced origin cannot entirely be ruled out, the particular architecture and fabric of the sediment, rip-up clasts and three subunits point to deposition by a tsunami. As such, it represents the first stratigraphical evidence of a prehistoric, mid-Holocene tsunami in NW Western Australia. It was OSL-dated to 5400-4300 years ago, thus postdating the regional mid-Holocene sea-level highstand.

  15. Kashmir Basin Fault and its tectonic significance in NW Himalaya, Jammu and Kashmir, India

    NASA Astrophysics Data System (ADS)

    Shah, A. A.

    2015-10-01

    The Kashmir Basin Fault is located in the Jammu and Kashmir region of Kashmir Basin in NW Himalaya, India. It is a classic example of an out-of-sequence thrust faulting and is tectonically active as observed from multiple geological evidences. Its geomorphology, structure and lateral extent indicate significant accommodation of stress since long, which is further supported by the absence of a large earthquake in this region. It seems this fault is actively accommodating some portion of the total India-Eurasia convergence, apart from two well-recognised active structures the Medlicott-Wadia Thrust and the Main Frontal Thrust, which are referred in Vassallo et al. (Earth Planet Sci Lett 411:241-252, 2015). This requires its quantification and inclusion into slip distribution scheme of NW Himalaya. Therefore, it should be explored extensively because this internal out-of-sequence thrust could serve major seismic hazard in KB, repeating a situation similar to Muzaffarabad earthquake of Northern Pakistan in 2005.

  16. New Insight Into The Crustal Structure of The Continental Margin Off NW Sabah/borneo

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Franke, D.; Behain, D.; Meyer, H.

    The continental margin offshore NW Sabah/Borneo (Malaysia) has been investigated with reflection and refraction seismics, magnetics, and gravity during the recent cruise BGR01-POPSCOMS. A total of 4000 km of geophysical profiles has been acquired, thereof 2900 km with reflection seismics. Like in major parts of the South China Sea, the area seaward of the Sabah Trough consists of extended continental lithosphere. We found evidence that the continental crust also underlies the continental slope land- ward of the Trough, a fact that raises many questions about the tectonic history and development of this margin. The characteristic pattern of rotated fault blocks and half grabens and the carbon- ates which are observed all over the Dangerous Grounds can be traced a long way landward of the Sabah Trough beneath the sedimentary succession of the upper plate. The magnetic anomalies which are dominated by the magnetic signatures of relatively young volcanic features also continue under the continental slope. The sedimentary rocks of the upper plate, in contrast, seem to generate hardly any magnetic anoma- lies. We suspect that the volcanic activity coincided with the collision of Borneo and the Dangerous Grounds in middle or late Miocene time. The emplacement of an al- lochtonous terrane on top of the extended continental lithosphere could be explained by overthrusting as a result of the collision or it could be related to gravity sliding following a broad uplift of NW Borneo at the same time.

  17. Feeding and production of zooplankton in the Catalan Sea (NW Mediterranean)

    NASA Astrophysics Data System (ADS)

    Saiz, Enric; Calbet, Albert; Atienza, Dacha; Alcaraz, Miquel

    2007-08-01

    Zooplankton are key components of the structure and functioning of marine planktonic food webs. They are the main link of planktonic primary production towards top pelagic consumer levels (fish), and play a relevant role on the nutrient recycling in the water column and on the export of particulate matter out of the photic zone. In this paper, we review the present knowledge on the feeding and production of zooplankton in the Catalan Sea (NW Mediterranean), with special emphasis on copepods. Feeding of zooplankton in the Catalan Sea appears typically food limited, with average daily rations on a yearly basis in the order of 48% body C d -1. Heterotrophic prey constitute a relevant fraction of their diet, as an alternative to the scarce phytoplankton in the area. From a structural point of view, the trophic impact and control of their prey populations are low on standing stocks but, at certain times, zooplankton can exert a meaningful effect on their prey production. Regarding zooplankton production, the available estimates of growth rates in the area are based on the egg production rate of copepods. Egg production rates appear to be limited, especially in summer. Tentative estimates of copepod production in the area are in the order of 20-40 mg C m -2 d -1. In conclusion, this review confirms that the oligotrophic character of the NW Mediterranean constrains the feeding activity and production of zooplankton.

  18. Organic micropollutants in coastal waters from NW Mediterranean Sea: sources distribution and potential risk.

    PubMed

    Sánchez-Avila, Juan; Tauler, Romà; Lacorte, Silvia

    2012-10-01

    This study provides a first estimation on the sources, distribution and risk of organic micropollutants (OMPs) in coastal waters from NW Mediterranean Sea. Polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, phthalates and alkylphenols were analyzed by solid phase extraction and gas chromatography coupled to tandem mass spectrometry (SPE-GC-EI-MS/MS). River waters and wastewater treatment plant effluents discharging to the sea were identified as the main sources of OMPs to coastal waters, with an estimated input amount of around of 25,800 g d(-1). The concentration of ΣOMPs in coastal areas ranged from 17.4 to 8442 ng L(-1), and was the highest in port waters, followed by coastal and river mouth seawaters. A summarized overview of the patterns and sources of OMP contamination on the investigated coastal sea waters of NW Mediterranean Sea, as well as of their geographical distribution was obtained by Principal Component Analysis of the complete data set after its adequate pretreatment. Alkylphenols, bisphenol A and phthalates were the main contributors to ΣOMPs and produced an estimated significant pollution risk for fish, algae and the sensitive mysid shrimp organisms in seawater samples. The combination of GC-MS/MS, chemometrics and risk analysis is proven to be useful for a better control and management of OMP discharges. PMID:22706016

  19. Substantial Improvement of Short Wavelength Response in n-SiNW/PEDOT:PSS Solar Cell

    NASA Astrophysics Data System (ADS)

    Ge, Zhaoyun; Xu, Ling; Cao, Yunqing; Wu, Tao; Song, Hucheng; Ma, Zhongyuan; Xu, Jun; Chen, Kunji

    2015-08-01

    We report herein on the effects of silicon nanowire with different morphology on the device performance of n-SiNW/PEDOT:PSS hybrid solar cells. The power conversion efficiency (PCE) and external quantum efficiency (EQE) of the SiNW/PEDOT:PSS hybrid solar cells can be optimized by varying the length of the silicon nanowires. The optimal length of silicon nanowires is 0.23 μm, and the hybrid solar cell with the optimal length has the V oc of 569 mV, J sc of 30.1 mA/cm2, and PCE of 9.3 %. We fabricated more isolated silicon nanowires with the diluted etching solution. And the J sc of the hybrid solar cell with more isolated nanowires has a significant enhancement, from 30.1 to 33.2 mA/cm2. The remarkable EQE in the wavelength region of 300 and 600 nm was also obtained, which are in excess of 80 %. Our work provides a simple method to substantially improve the EQE of hybrid solar cell in the short wavelength region.

  20. A multiproxy study of Holocene water-depth and environmental changes in Lake St Ana, Eastern Carpathian Mountains, Romania

    NASA Astrophysics Data System (ADS)

    Magyari, E. K.; Buczkó, K.; Braun, M.; Jakab, G.

    2009-04-01

    allow the following main inference to be made: Lake Saint Ana is a vulnerable ecosystem; hydrological, biological and chemical processes in the lake are heavily influenced by the lakeshore forest and the soil underlying it. In-lake productivity is higher under deciduous canopy and litter, and considerably repressed by coniferous canopy and litter. The lake today subsists in a managed environment, that is however far from its natural state. This would be a dense Fagus sylvatica forest supplying more nutrients and keeping up a more productive in-lake flora and fauna. An overview of the regional Holocene lake-level records suggests that the general lake-level trends of this study agree with other records in the region, except for the lat 2,700 years, for which conflicting trends were found. The pollen based palaeo-precipitation record in NW Romania signals lower precipitation, while our, and some other records, signal significant increase in available moisture. Further studies are needed to resolve this problem.

  1. Photocurrent enhancement of SiNW-FETs by integrating protein-shelled CdSe quantum dots

    NASA Astrophysics Data System (ADS)

    Moh, Sang Hyun; Kulkarni, Atul; San, Boi Hoa; Lee, Jeong Hun; Kim, Doyoun; Park, Kwang Su; Lee, Min Ho; Kim, Taesung; Kim, Kyeong Kyu

    2016-01-01

    We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 106, the highest value compared to other SiNW-based devices in the visible light range.We proposed a new strategy to increase the photoresponsivity of silicon NW field-effect transistors (FETs) by integrating CdSe quantum dots (QDs) using protein shells (PSs). CdSe QDs were synthesized using ClpP, a bacterial protease, as protein shells to control the size and stability of QD and to facilitate the mounting of QDs on SiNWs. The photocurrent of SiNW-FETs in response to light at a wavelength of 480 nm was enhanced by a factor of 6.5 after integrating CdSe QDs because of the coupling of the optical properties of SiNWs and QDs. As a result, the photoresponsivity to 480 nm light reached up to 3.1 × 106, the highest value compared to other SiNW-based devices in the visible light range. Electronic supplementary information (ESI) available: Materials and methods. See DOI: 10.1039/c5nr07901b

  2. Recent warming of lake Kivu.

    PubMed

    Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  3. Recent Warming of Lake Kivu

    PubMed Central

    Katsev, Sergei; Aaberg, Arthur A.; Crowe, Sean A.; Hecky, Robert E.

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient. PMID:25295730

  4. Lake evaporation estimates in tropical Africa (Lake Ziway, Ethiopia)

    NASA Astrophysics Data System (ADS)

    Vallet-Coulomb, Christine; Legesse, Dagnachew; Gasse, Françoise; Travi, Yves; Chernet, Tesfaye

    2001-05-01

    Estimates of evaporation from an open shallow lake in tropical Africa (Lake Ziway, Main Ethiopian Rift) are made by using monthly hydrometeorological data available for the past three decades. On the one hand, annual average estimates are inferred from three climatic approaches, which can be applied in areas with limited meteorological data. The lake energy balance yields an evaporation rate of 1780 mm yr -1, assuming a Bowen ratio of 0.15 (that of Lake Victoria). The Penman method gives an annual evaporation rate of 1870 mm. The complementary relationship lake evaporation model (CRLE) applied on monthly averaged values of air temperature, air humidity and sunshine duration gives 1730 mm yr -1. The sensitivity of each method to changes in input variables is analyzed in order to test the stability of the resulting estimates. This helps discuss uncertainties and possible inter-annual variations of the evaporation rate. On the other hand, the monthly lake level records together with precipitation and river discharge data between 1969 and 1990, allow us to estimate the water balance, providing an annual rate of 1937 mm for the combined evaporation and groundwater losses. The chloride budget is used to discriminate the groundwater from the evaporation loss. It gives us an annual evaporation rate of 1740 mm and a corresponding groundwater loss of 200 mm yr -1. The groundwater loss estimate is of the same order of magnitude as the surface outflow, but the associated error in the former is significant because the result is sensitive to the poorly known chloride content of river inflows. Our results can be used to forecast the impact of increased water consumption in the basin.

  5. Neoichnology at lake margins: Implications for paleo-lake systems

    NASA Astrophysics Data System (ADS)

    Hamer, Jessica M. M.; Sheldon, Nathan D.

    2010-07-01

    Neoichnological studies provide significant information that can aid in the interpretation of ancient ichnological assemblages. Here we examine, for the first time, the pattern in both vertebrate and invertebrate trace distribution and abundance that can be seen in two geographically separate, but broadly analogous, contemporary semi-arid climate lake margin settings in an effort to describe taphonomic processes relevant to paleo-lake systems. Lake margin to supralittoral zone transects were made at Ruby Reservoir, Montana (USA) and La Sotonera, Spain and vegetation cover, trace cover %, trace diversity, and substrate characteristics were recorded. Similar patterns in trace distribution were seen through the eulittoral to supralittoral zones, with the majority of traces identified within a single transect present at both sites. However, a few traces attributed to larger organisms were found to be unique to each and in some instances, could to be assigned to a specific trace maker. The eulittoral zone was considered to have characteristics attributable to the Scoyenia ichnofacies, however, analysis of the supralittoral zone shows some characteristics of both the Coprinisphaera and the Mermia ichnofacies. In addition, a transitional zone between a Scoyenia-like ichnofacies and a fully terrestrial assemblage was found, which may enable continental ichnofacies to be further refined for application to paleo-lake systems. Study of the distribution of traces with distance along the transects also suggests taphonomic biases against the preservation of certain types of traces (e.g., avian) due to seasonal fluctuations of the lake level and the subsequent reduced preservation potential for lake-proximal traces.

  6. Thermokarst lakes, drainage, and drained basins

    USGS Publications Warehouse

    Grosse, G.; Jones, B.; Arp, C.; Shroder, John F.

    2013-01-01

    Thermokarst lakes and drained lake basins are widespread in Arctic and sub-Arctic permafrost lowlands with ice-rich sediments. Thermokarst lake formation is a dominant mode of permafrost degradation and is linked to surface disturbance, subsequent melting of ground ice, surface subsidence, water impoundment, and positive feedbacks between lake growth and permafrost thaw, whereas lake drainage generally results in local permafrost aggradation. Thermokarst lakes characteristically have unique limnological, morphological, and biogeochemical characteristics that are closely tied to cold-climate conditions and permafrost properties. Thermokarst lakes also have a tendency toward complete or partial drainage through permafrost degradation and erosion. Thermokarst lake dynamics strongly affect the development of landscape geomorphology, hydrology, and the habitat characteristic of permafrost lowlands.

  7. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500...

  8. 33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500...

  9. SKY LAKES ROADLESS AREA AND MOUNTAIN LAKES WILDERNESS, OREGON.

    USGS Publications Warehouse

    Smith, James G.; Benham, John R.

    1984-01-01

    Based on a mineral survey of the Sky Lakes Roadless Area and the Mountain Lakes Wilderness, Oregon, the areas have little or no promise for the occurrence of metallic-mineral resources or geothermal energy resources. Nonmetallic resources exist in the areas, but other areas outside the roadless area and wilderness also contain resources of volcanic cinders, scoria, ash, breccia, and sand and gravel which are easier to obtain and closer to markets. The roadless area and wilderness are not geologically favorable for metallic deposits, or for coal, oil, or gas resources.

  10. 3D Full Seismic Waveform Tomography of NW Turkey and Surroundings

    NASA Astrophysics Data System (ADS)

    Cubuk, Yesim; Fichtner, Andreas; Taymaz, Tuncay

    2015-04-01

    Northward collision of the Arabian plate with the Eurasian plate, and interaction of the motion between dynamic processes originated from the subduction of the African plate beneath the Aegean generated very complex tectonic structures in the study region. Western Turkey is among one of the most active extensional regions in the world and the study area is mainly located where the extensional Aegean and the right-lateral strike-slip North Anatolian Fault Zone (NAFZ) intersects. Therefore, the tectonic framework of the NW Turkey and the Marmara region is mainly characterized by the transition between the strike-slip tectonics to the extensional tectonics. The Sea of Marmara region has been subjected to several active and passive seismic investigations, nevertheless the accurate knowledge on the heterogeneity in the crust and upper mantle beneath the study area still remains enigmatic. On small-scale tomography problems, seismograms strongly reflect the effects of heterogeneities and the scattering properties of the Earth. Thus, the knowledge of high-resolution seismic imaging with an improved 3D radially anisotropic crustal model of the NW Turkey will enable better localization of earthquakes, identification of faults as well as the improvement of the seismic hazard assessment. For this purpose, we aim to develop 3D radially anisotropic subsurface structure of the Sea of Marmara and NW Turkey crust based on full waveform adjoint tomography method. The earthquake data were principally obtained from the Kandilli Observatory and Earthquake Research Institute (KOERI) and Earthquake Research Center (AFAD-DAD) database. In addition to this, some of the seismic waveform data extracted from the Hellenic Unified Seismic Network (HUSN) stations that are located within our study region were also used in this study. We have selected and simulated waveforms of earthquakes with magnitudes 4.0 ≤ Mw ≤ 6.7 occurred in the period between 2007-2014 to determine the 3D velocity

  11. Along and across arc geochemical variations in NW Central America: Evidence for involvement of lithospheric pyroxenite

    NASA Astrophysics Data System (ADS)

    Heydolph, Ken; Hoernle, Kaj; Hauff, Folkmar; Bogaard, Paul van den; Portnyagin, Maxim; Bindeman, Ilya; Garbe-Schönberg, Dieter

    2012-05-01

    The Central American Volcanic Arc (CAVA) has been the subject of intensive research over the past few years, leading to a variety of distinct models for the origin of CAVA lavas with various source components. We present a new model for the NW Central American Volcanic Arc based on a comprehensive new geochemical data set (major and trace element and Sr-Nd-Pb-Hf-O isotope ratios) of mafic volcanic front (VF), behind the volcanic front (BVF) and back-arc (BA) lava and tephra samples from NW Nicaragua, Honduras, El Salvador and Guatemala. Additionally we present data on subducting Cocos Plate sediments (from DSDP Leg 67 Sites 495 and 499) and igneous oceanic crust (from DSDP Leg 67 Site 495), and Guatemalan (Chortis Block) granitic and metamorphic continental basement. We observe systematic variations in trace element and isotopic compositions both along and across the arc. The data require at least three different endmembers for the volcanism in NW Central America. (1) The NW Nicaragua VF lavas require an endmember with very high Ba/(La, Th) and U/Th, relatively radiogenic Sr, Nd and Hf but unradiogenic Pb and low δ18O, reflecting a largely serpentinite-derived fluid/hydrous melt flux from the subducting slab into a depleted N-MORB type of mantle wedge. (2) The Guatemala VF and BVF mafic lavas require an enriched endmember with low Ba/(La, Th), U/Th, high δ18O and radiogenic Sr and Pb but unradiogenic Nd and Hf isotope ratios. Correlations of Hf with both Nd and Pb isotopic compositions are not consistent with this endmember being subducted sediments. Granitic samples from the Chiquimula Plutonic Complex in Guatemala have the appropriate isotopic composition to serve as this endmember, but the large amounts of assimilation required to explain the isotope data are not consistent with the basaltic compositions of the volcanic rocks. In addition, mixing regressions on Nd vs. Hf and the Sr and O isotope plots do not go through the data. Therefore, we propose that this

  12. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    USGS Publications Warehouse

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  13. Monitoring change in Great Salt Lake

    USGS Publications Warehouse

    Naftz, David L.; Angeroth, Cory E.; Freeman, Michael L.; Rowland, Ryan C.; Carling, Gregory

    2013-01-01

    Despite the ecological and economic importance of Great Salt Lake, only limited water quality monitoring has occurred historically. To change this, new monitoring stations and networks—gauges of lake level height and rate of inflow, moored buoys, and multiple lake-bottom sensors—will provide important information that can be used to make informed decisions regarding future management of the Great Salt Lake ecosystem.

  14. Teshekpuk Lake, Alaska

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This ASTER image of Teshekpuk Lake on Alaska's North Slope, within the National Petroleum Reserve, was acquired on August 15, 2000. It covers an area of 58.7 x 89.9 km, and is centered near 70.4 degrees north latitude, 153 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 58.7 by 89.9 kilometers (36.4 by 55.7 miles) Location: 70.4 degrees North latitude, 153 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and 1 Original Data Resolution: ASTER 30 meters (98.4 feet) Dates Acquired: August 15, 2000

  15. A lake as a natural integrator of linear processes: Application to Lake Kinneret (Israel) and Lake Biwa (Japan)

    NASA Astrophysics Data System (ADS)

    Rimmer, Alon; Boger, Michael; Aota, Yasuaki; Kumagai, Michio

    2006-03-01

    The major hydrological variables that may cause long-term salinity changes in fresh water lakes are the volume of the lake, stream and/or groundwater inflows and outflows, direct rainfall, stream, groundwater, and rainfall salinity and evaporation. Measurements of these variables are usually subject to natural fluctuations and unavoidable errors of the measured data. Therefore, evaluation of the contribution of each component to the long-term salinity trends is difficult. In this work, it is shown that since salinization processes are linear, lakes are able to retain a 'solute influx memory', which records information about their lake-watershed-climate relationship in the past. Our objective was to test and verify a system approach method, which evaluates this 'memory', i.e. investigates the causes of long-term salinization processes in fresh water lakes. With this approach, a general expression is developed that represents the lake as a natural integrator of linear processes in space and time. The long-term change of the chloride concentration in the lake (representing salinity) reflects the long-term changes in each of the various past hydrological variables. The general theory of the lake as a natural integrator was tested by examination of the long-term salinity changes in Lake Kinneret, Israel, and Lake Biwa, Japan. The hydrology and salinity of both lakes are well monitored for several decades. In the analysis of Lake Kinneret, the long-term measurements of inflows, outflows and lake salinity were used to verify that the salinization mechanism follows the theory of complete mixing (system identification). In Lake Biwa the same approach was used, however, we assumed that the salinization mechanism was 'complete mixing', and the long-term measurements of the lake hydrology were used to investigate the reasons for increasing salinity (system detection). Since the system analysis is affected by uncertainties of the measured variables, a stochastic component was

  16. Lake Okeechobee seepage monitoring network

    USGS Publications Warehouse

    McKenzie, Donald J.

    1973-01-01

    This report summarizes the data collected at the five original monitoring sites along the south shore of Lake Okeechobee from January 29, 1970 to June 28, 1972. In order to use the hydrographs in this report to full advantage, they should be studied in conjunction with Meyer's graphs and text (1971). During steady-state conditions, water seeps from the lake through the filtercake and through the aquifers beneath the dike. At those sites where the filtercake is missing, or has about the same permeability as the aquifers, the seepage from the lake is about equivalent to the flow through the aquifers. Present data are insufficient to determine whether or not filtercake buildup has reduced seepage. No appreciable change in drainage occurred during the observed period.

  17. Lake Effect Snow Covers Buffalo

    NASA Technical Reports Server (NTRS)

    2002-01-01

    An average of one foot of snow per day has fallen on Buffalo, New York, since Christmas Eve, resulting in a total of up to 5 feet from December 24-28. The snow fell very heavily, with accumulations of up to 3 inches per hour. Cold winds blowing along the surface of Lake Erie pick up warmth and moisture, which falls as snow as the warm air rises. This image was acquired by the Geostationary Operational Environmental Satellite (GOES), operated by NOAA, on December 27, 2001, at 12:32 p.m. EST. The scene shows thick bands of clouds extending from the eastern tip of Lake Erie and over Buffalo. The arrows show the wind direction, which is blowing down the length of the lake. Image and animation by Robert Simmon, based on data from the NASA GOES Project Science Office.

  18. Great Lakes management: Ecological factors

    NASA Astrophysics Data System (ADS)

    Sonzogni, W. C.; Robertson, A.; Beeton, A. M.

    1983-11-01

    Although attempts to improve the quality of the Great Lakes generally focus on chemical pollution, other factors are important and should be considered Ecological factors, such as invasion of the lakes by foreign species, habitat changes, overfishing, and random variations in organism populations, are especially influential. Lack of appreciation of the significance of ecological factors stems partly from the inappropriate application of the concept of eutrophication to the Great Lakes. Emphasis on ecological factors is not intended to diminish the seriousness of pollution, but rather to point out that more cost-effective management, as well as more realistic expectations of management efforts by the public, should result from an ecosystem management approach in which ecological factors are carefully considered.

  19. First evidence of successful natural reproduction by planted lake trout in Lake Huron

    USGS Publications Warehouse

    Nester, Robert T.; Poe, Thomas P.

    1984-01-01

    Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

  20. STATUS OF MYSIS RELICTA IN LAKE SUPERIOR

    EPA Science Inventory

    The status of different components of the lower food web is reported for Lake Superior. Results are preliminary summaries from the Binational collaboration in 2005, which measured the lower food web at the request of the Lake Superior Fisheries Technical Committee and Lake Superi...

  1. Great Lakes Education Booklet, 1990-1991.

    ERIC Educational Resources Information Center

    Michigan State Dept. of Natural Resources, Lansing.

    This booklet integrates science, history, and environmental education to help students acquire a basic understanding of the importance of the Great Lakes located in the United States. The packet also contains a Great Lakes Basin resource map and a sand dune poster. These materials introduce students to a brief history of the lakes, the diversity…

  2. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.34 Finger Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  3. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.34 Finger Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  4. 27 CFR 9.99 - Clear Lake.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.99 Clear Lake. (a) Name. The name of the viticultural area described in this section is “Clear Lake.” (b) Approved Maps. The appropriate maps for determining the boundaries of the Clear Lake viticultural area are four...

  5. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.34 Finger Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  6. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.34 Finger Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  7. 27 CFR 9.34 - Finger Lakes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.34 Finger Lakes. (a) Name. The name of the viticultural area described in this section is “Finger Lakes.” (b) Approved maps. The appropriate maps for determining the boundaries of the Finger Lakes viticultural...

  8. 27 CFR 9.83 - Lake Erie.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lake Erie viticultural area are four...

  9. 27 CFR 9.83 - Lake Erie.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lake Erie viticultural area are four...

  10. 27 CFR 9.83 - Lake Erie.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lake Erie viticultural area are four...

  11. 27 CFR 9.83 - Lake Erie.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lake Erie viticultural area are four...

  12. 27 CFR 9.83 - Lake Erie.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.83 Lake Erie. (a) Name. The name of the viticultural area described in this section is “Lake Erie.” (b) Approved maps. The appropriate maps for determining the boundaries of the Lake Erie viticultural area are four...

  13. 27 CFR 9.99 - Clear Lake.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.99 Clear Lake. (a) Name. The name of the viticultural area described in this section is “Clear Lake.” (b) Approved Maps. The appropriate maps for determining the boundaries of the Clear Lake viticultural area are four...

  14. 27 CFR 9.99 - Clear Lake.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.99 Clear Lake. (a) Name. The name of the viticultural area described in this section is “Clear Lake.” (b) Approved Maps. The appropriate maps for determining the boundaries of the Clear Lake viticultural area are four...

  15. 27 CFR 9.146 - Lake Wisconsin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., Columbia County, where Spring Creek enters Lake Wisconsin; (2) From the point of beginning, follow the... Bay, Sauk County, where the Wisconsin River becomes Lake Wisconsin again on the map; (4) Then... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Lake Wisconsin....

  16. 27 CFR 9.146 - Lake Wisconsin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., Columbia County, where Spring Creek enters Lake Wisconsin; (2) From the point of beginning, follow the... Bay, Sauk County, where the Wisconsin River becomes Lake Wisconsin again on the map; (4) Then... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Lake Wisconsin....

  17. 27 CFR 9.146 - Lake Wisconsin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., Columbia County, where Spring Creek enters Lake Wisconsin; (2) From the point of beginning, follow the... Bay, Sauk County, where the Wisconsin River becomes Lake Wisconsin again on the map; (4) Then... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lake Wisconsin....

  18. 27 CFR 9.146 - Lake Wisconsin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., Columbia County, where Spring Creek enters Lake Wisconsin; (2) From the point of beginning, follow the... Bay, Sauk County, where the Wisconsin River becomes Lake Wisconsin again on the map; (4) Then... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Lake Wisconsin....

  19. 27 CFR 9.146 - Lake Wisconsin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., Columbia County, where Spring Creek enters Lake Wisconsin; (2) From the point of beginning, follow the... Bay, Sauk County, where the Wisconsin River becomes Lake Wisconsin again on the map; (4) Then... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Lake Wisconsin....

  20. Hydrology of Lake Butler, Orange County, Florida

    USGS Publications Warehouse

    Smoot, James L.; Schiffer, Donna M.

    1984-01-01

    Lake Butler is one of the lakes that collectively make up the Butler chain of lakes in the headwaters of the Kissimmee River, Florida. The bottom configuration of the lake is typical of relict karst features formed during lower stages in sea level. The top of the Floridan aquifer is 50 to 100 feet below the land surface. The drainage area of Lake Butler is approximately 14.5 sq mi and is comprised of sub-basins of other lakes in the vicinity. Surface outflow from Lake Butler is generally southward to Cypress Creek, a tributary of the Kissimmee River. The extremes in lake stage for the period 1933-81 are 94.67 ft on June 23, 1981 and 101.78 ft on September 13, 1960. The median lake stage for this period was 99.28 ft above sea level. The quality of water in Lake Butler is excellent, based on studies of physical, chemical, and biological conditions by the Orange County Pollution Control Department. The lake water is slightly acidic and soft (48 mg/L hardness as calcium carbonate). Pesticides in water were below detection levels at two sites sampled in the lake, but were detected in the bottom sediments. (USGS)

  1. A reactive nitrogen budget for Lake Michigan

    EPA Science Inventory

    The reactive nitrogen budget for Lake Michigan was reviewed and updated, making use of recent estimates of watershed and atmospheric nitrogen loads. The updated total N load to Lake Michigan was approximately double the previous estimate from the Lake Michigan Mass Balance study ...

  2. 36 CFR 13.1208 - Lake Camp.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Lake Camp. 13.1208 Section 13... § 13.1208 Lake Camp. Leaving a boat, trailer, or vehicle unattended for more than 72 hours at the facilities associated with the Lake Camp launching ramp is prohibited without authorization from...

  3. CALL FOR ABSTRACTS - PIT LAKES 2004

    EPA Science Inventory

    This call for abstracts is for the 11/16-18/2004 Pit Lakes 2004 meeting held in Reno, NV. This conference will provide a forum for the exchange of scientific information on current domestic and international pit lake approaches, including pit lakes from arid and wet regions throu...

  4. Exploration of Subglacial Lake Ellsworth

    NASA Astrophysics Data System (ADS)

    Ross, N.

    2012-12-01

    Antarctic subglacial lakes are thought to be extreme habitats for microbial life and may contain important records of ice sheet history within their lake-floor sediments. To find if this is true, and to answer the science questions that would follow, direct measurement and sampling of these environments is required. Ever since the water depth of Vostok Subglacial Lake in East Antarctica was shown to be >500 m, attention has been given to how these unique, ancient and pristine subglacial environments may be entered without contamination and adverse disturbance. Several organizations have offered guidelines on the desirable cleanliness and sterility requirements for direct sampling experiments, including the US National Academy of Sciences and the Scientific Committee on Antarctic Research. The aims, design and implementation of subglacial lake access experiments have direct relevance for the exploration of extra-terrestrial ice-covered bodies (e.g. Europa) and the search for microbial life elsewhere in the Solar System. This presentation summarizes the scientific protocols and methods being developed for the exploration of Ellsworth Subglacial Lake in West Antarctica, and provides an up-to-date summary of the status of the project. The proposed exploration, planned for December 2012, involves accessing the lake using a hot-water drill and deploying a sampling probe and sediment corer to allow in situ measurement and sample collection. Details are presented on how this can be undertaken with minimal environmental impact that maximizes scientific return without compromising the environment for future experiments. The implications of this experiment for the search for extra-terrestrial life will be discussed.

  5. Lake Volume Monitoring from Space

    NASA Astrophysics Data System (ADS)

    Crétaux, J.-F.; Abarca-del-Río, R.; Bergé-Nguyen, M.; Arsen, A.; Drolon, V.; Clos, G.; Maisongrande, P.

    2016-03-01

    Lakes are integrators of environmental change occurring at both the regional and global scale. They present a wide range of behavior on a variety of timescales (cyclic and secular) depending on their morphology and climate conditions. Lakes play a crucial role in retaining and stocking water, and because of the significant global environmental changes occurring at several anthropocentric levels, the necessity to monitor all morphodynamic characteristics [e.g., water level, surface (water contour) and volume] has increased substantially. Satellite altimetry and imagery are now widely used together to calculate lake and reservoir water storage changes worldwide. However, strategies and algorithms to calculate these characteristics are not straightforward, and specific approaches need to be developed. We present a review of some of these methodologies by using lakes over the Tibetan Plateau to illustrate some critical aspects and issues (technical and scientific) linked to the observation of climate change impact on surface waters from remote sensing data. Many authors have measured water variation using the limited remote sensing measurements available over short time periods, even though the time series are probably too short to directly link these results with climate change. Indeed, there are many processes and factors, like the influence of lake morphology, that are beyond observation and are still uncertain. The time response for lakes to reach a new state of equilibrium is a key aspect that is often neglected in current literature. Observations over a long period of time, including maintaining a constellation of comprehensive and complementary satellite missions with service continuity over decades, are therefore necessary especially when the ground gauge network is too limited. In addition, the design of future satellite missions with new instrumental concepts (e.g., SAR, SARin, Ka band altimetry, Ka interferometry) will also be suitable for complete

  6. Hydrology of Hunters Lake, Hernando County, Florida

    USGS Publications Warehouse

    Henderson, S.E.

    1986-01-01

    The size and shape of Hunters Lake, Florida has been significantly altered by development of the surrounding Spring Hill residential community. The lake is the largest in Hernando County, enlarged by lakeshore excavation and connection to nearby ponds to an area of 360 acres at an average stage of 17.2 ft above sea level. Hunters Lake is naturally a closed lake, but development of Spring Hill has resulted in a surface water outflow from the lake in its southwest corner. Inflow to the lake could occur on the east side during extreme high-water periods. The karst terrain of the Hunters Lake area is internally drained through permeable soils, depressions, and sinkholes, and natural surface drainage is absent. The underlying Floridan aquifer system is unconfined except locally near coastal springs. Flow in the groundwater system is to the west regionally and to the southwest in the immediate area of Hunters Lake. Water level gradients in the groundwater system increase from 1.4 ft/mi east of the lake to about 8 ft/mi southwest of the lake. Hunters Lake is hydraulically connected to the groundwater system, receiving groundwater on the northeast side and losing water to the groundwater system on the southwest side. This close relationship with the groundwater system is demonstrated by graphical and numerical comparison of Hunters Lake stage with water levels in nearby groundwater sites. During 1965-84, the stage of Hunters Lake fluctuated between 12.48 and 20.7 ft above sea level. Because area lakes are all directly affected by groundwater levels, they also show a close relationship with water levels in Hunters Lake. Analysis of water quality data for Hunters Lake indicates that the water of the lake is a soft calcium bicarbonate type with ionic concentrations higher than in water from nearby shallow wells and lower than in water from the Upper Floridan aquifer. Samples collected in 1981-1983 indicate slightly higher levels of ionic concentration than in 1965

  7. Fertilization of eggs of Lake Michigan lake trout Salvelinus namaycush in lake water: Effect of PCBs (Aroclor 1254)

    USGS Publications Warehouse

    Foster, N.R.; Berlin, W.H.

    1997-01-01

    Various studies indicate that PCBs appear to have an adverse effect on the viability of fertilized eggs and subsequent early life stages of lake trout and related species. Our tests detected no impairment of fertilization of lake trout eggs in PCB-dosed lake water. The concentration of PCBs in the fertilization medium that we used was more than 20 times as high as estimated ambient levels in southeastern Lake Michigan and it appears unlikley that ambient levels of PCBs in the water at fertilization would contribute significantly to the apparent widespread reproductive failure of lake trout there.

  8. Remote sensing and lake eutrophication

    NASA Technical Reports Server (NTRS)

    Wrigley, R. C.; Horne, A. J.

    1974-01-01

    An infrared photograph of part of Clear Lake, Cal., shows complex patterns of blue-green algal blooms which were not observed by conventional limnological techniques. Repeated observations of patterns such as these can be used to chart the surface movement of these buoyant algae and can also be used to help control algal scums in eutrophic lakes. Although it is believed that most of the observed patterns resulted from Aphanizomenon (a few were also observed which resulted from suspended sediment), spectral signatures of the algal patterns varied.

  9. Distribution of heavy metals in sediment cores of Lake Pamvotis (Greece): a pollution and potential risk assessment.

    PubMed

    Ioannides, K; Stamoulis, K; Papachristodoulou, C; Tziamou, E; Markantonaki, C; Tsodoulos, I

    2015-01-01

    Concentrations and vertical distributions of metals in surface sediments of Lake Pamvotis (NW Greece) were assessed using energy-dispersive X-ray fluorescence spectrometry. A wide range of values was determined, associated with the specific types of contaminating effluents draining into different parts of the lake. Overall, Cr levels ranged from 43 to 3295 mg kg(-1), Ni from 13 to 372 mg kg(-1), Cu from 15 to 24,985 mg kg(-1), Zn from 129 to 22,983 mg kg(-1), Zr from 64 to 4063 mg kg(-1) and Pb from 19 to 2634 mg kg(-1). Principal component analysis revealed distinct elemental fingerprints in each sampling location, while correlation analysis and hierarchical agglomerative cluster analysis provided insight to metal association and pollution sources. Enrichment factors and geoaccumulation indices were calculated to quantify sediment contamination, and potential ecotoxic effects were evaluated based on sediment quality guidelines. Moderate to very severe enrichment in Zn, Cu and Pb was evidenced in sediments near the lake's outflow. The proximity of these sampling points to a heavy traffic national road suggests that roadway runoff is the dominant source of elevated metal levels. Contribution from municipal sewage water discharges from the nearby communities should also be accounted for. Moderate to very severe Zn and Pb enrichment was determined in the vicinity on the main lake's inflow, primarily associated with runoff and leaching from agricultural land. Very severe to extremely severe Cr enrichment was detected in the same location, most likely associated with wastewater discharged into the lake over several decades, by nearby-operating leather tanneries. The above two locations were ranked at the highest priority level in terms of potential ecological risk. PMID:25527434

  10. Post Audit of Lake Michigan Lake Trout PCB Model Forecasts

    EPA Science Inventory

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  11. Feeding ecology of lake whitefish larvae in eastern Lake Ontario

    USGS Publications Warehouse

    Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

    2009-01-01

    We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

  12. Crustal structure between Lake Mead, Nevada, and Mono Lake, California

    USGS Publications Warehouse

    Johnson, Lane R.

    1964-01-01

    Interpretation of a reversed seismic-refraction profile between Lake Mead, Nevada, and Mono Lake, California, indicates velocities of 6.15 km/sec for the upper layer of the crust, 7.10 km/sec for an intermediate layer, and 7.80 km/sec for the uppermost mantle. Phases interpreted to be reflections from the top of the intermediate layer and the Mohorovicic discontinuity were used with the refraction data to calculate depths. The depth to the Moho increases from about 30 km near Lake Mead to about 40 km near Mono Lake. Variations in arrival times provide evidence for fairly sharp flexures in the Moho. Offsets in the Moho of 4 km at one point and 2 1/2 km at another correspond to large faults at the surface, and it is suggested that fracture zones in the upper crust may displace the Moho and extend into the upper mantle. The phase P appears to be an extension of the reflection from the top of the intermediate layer beyond the critical angle. Bouguer gravity, computed for the seismic model of the crust, is in good agreement with the measured Bouguer gravity. Thus a model of the crustal structure is presented which is consistent with three semi-independent sources of geophysical data: seismic-refraction, seismic-reflection, and gravity.

  13. Distribution of haloacetic acids in the water columns of the Laurentian Great Lakes and Lake Malawi.

    PubMed

    Scott, Brian F; Spencer, Christine; Marvin, Christopher H; MacTavish, David C; Muir, Derek C G

    2002-05-01

    Haloacetic acids (HAAs) are persistent and mildly phytotoxic compounds that have been detected in many aquatic environments, including the waters of the Great Lakes. Sources of HAAs, especially of trifluoroacetic acid (TFA), are not well understood. In this study we assessed the influence of urbanization on the concentrations and profiles of HAAs in the Laurentian Great Lakes and in Lake Malawi, an African Great Lake. Vertical depth profiles for these compounds were taken for each of the Great Lakes with additional profiles taken 2 years later for Lakes Erie and Ontario. The results showed that while TFA was relatively constant throughout the water column, the chloroacetic acids (CAAs) varied with depth. There was a trend of increasing TFA proceeding from Lake Superior to Lake Ontario (18-150 ng/L). Total CAA concentrations were relatively constant throughout the lakes (approximately 500 ng/L) with dichloroacetic acid being the most abundant. No bromoacetic acids were detected. In the Detroit River, a connecting channel between Lakes Huron and Erie, the TFA values were similar to those in Lake Huron, but the CAAs levels were higher than in the upstream lakes and dependent on location, indicating inputs from urban areas along the river. These results were compared to those from Lake Malawi, which has a high population density within the watershed but no heavy industry. CAAs were nondetectable, and TFA concentrations were just at the detection limit (1 ng/L). Total HAA in the water column of Lakes Superior and Huron was compared to annual precipitation inputs at a site situated near both lakes. For Lake Huron, precipitation was a minor contributor to the total HAA inventory of the lake, but for Lake Superior precipitation could be the major contributor to the mass of HAA in this lake. Generally, high HAA levels paralleled the degree of industrial activity in the adjacent waters.

  14. Patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes

    USGS Publications Warehouse

    Miller, Michael A.; Madenjian, Charles P.; Masnado, Robert G.

    1992-01-01

    To investigate spatial and temporal patterns of organochlorine contamination in lake trout from Wisconsin waters of the Great Lakes, we examined laboratory contaminant analysis data of muscle tissue samples from Lake Michigan (n=317) and Lake Superior (n=53) fish. Concentrations of polychlorinated biphenyls (PCBs), chlordane, and dieldrin, reported as mg/kg wet weight in 620 mm to 640 mm mean length Lake Michigan lake trout, decreased over time. Mean total PCB concentration declined exponentially from 9.7 in 1975 to 1.9 in 1990. Total chlordane concentration declined 63 percent from 0.48 in 1983 to 0.18 in 1990, and dieldrin declined 52 percent during this same period, from 0.21 to 0.10. The bioaccumulation rate of PCBs is significantly lower for lake trout inhabiting Lake Michigan's midlake reef complex, compared to lake trout from the nearshore waters of western Lake Michigan. Organochlorine compound concentrations were greater in Lake Michigan lake trout than Lake Superior fish. Lake Superior lean lake trout and siscowet exhibited similar rates of PCB bioaccumulation despite major differneces in muscle tissue lipid content between the two subspecies. The lack of a significant difference in the PCB bioaccumulation rates of lean trout and siscowet suggests that lipid content may not be an important factor influencing PCB bioaccumulation in lake trout, within the range of lipid concentrations observed. Relative concentrations of the various organochlorine contaminants found in lake trout were highly correlated, suggesting similar mass balance processes for these compounds. Evidence presented revealing spatial and temporal patterns of organochlorine contamination may be of value in reestablishing self-sustaining populations of lake trout in Lake Michigan.

  15. Middle Miocene coralline algal facies from the NW Transylvanian Basin (Romania)

    NASA Astrophysics Data System (ADS)

    Chelaru, Ramona; Bucur, Ioan I.; Sǎsǎran, Emanoil; Bǎlc, Ramona; Tǎmas, Tudor

    2016-04-01

    The current study focus on the coralline algae from the Middle Miocene limestones in NW Transylvania to provide an outline for their systematics and palaeoecology. The investigated samples were collected from three carbonate outcrops: Vǎlenii Șomcutei, Ciolt 1 and Ciolt 2, named after the respective localities situated in the vicinity of the Țicǎu-Preluca Mountains (NW Romania). The microfacies analysis suggest shallowing upward tendency in middle to proximal shelf environments. The coralline algae are present in the carbonate successions as detritus, branches, crusts and rhodoliths. The Vǎlenii Șomcutei section shows a depositional model where large and spheroidal rhodoliths develop in high energy conditions, most probably generated by storm waves. The sections from the Ciolt area are distinguished by the presence of green algae in association with the encrusting and geniculate coralline specimens. The identified species belong to Ord. Corallinales (Hydrolithon, Spongites, Lithophyllum, Jania), Hapalidales (Lithothamnion and Mesophyllum) and Sporolithales (Sporolithon). In the taxonomic identification of coralline red algae we used as many diagnostic features as possible, known from the description of present - day species, such as: shape of epithallial cells and roof morphology for melobesioids; presence/absence of a layer of elongated cells below sporangial compartments and number of cells in paraphyses for sporolithoids. The identified coralline algal assemblages are discussed according to different paleoenvironmental conditions (paleo-depth, hydrodynamic energy) and then compared with similar fossil assemblages and recent analogs like modern maërl and rhodolith pavements. The study of the calcareous nannoplankton assemblages from the Vǎlenii Șomcutei section [1] and the presence of previously dated tuffite intercalations of Dej Tuff [2] in the two sections near the Ciolt village confirm the Badenian age (NN5) of these deposits. [1] Chelaru R., S

  16. Rapid hydrological response to central Andean Plateau uplift, NW-Argentina

    NASA Astrophysics Data System (ADS)

    Rohrmann, Alexander; Sachse, Dirk; Strecker, Manfred R.; Mulch, Andreas; Pingel, Heiko; Alonso, Ricardo N.

    2015-04-01

    The response of the regional and global hydrological cycle, vegetation and erosion to tectonic surface uplift and topographic growth of the world's largest orogenic plateaus and their flanking ranges is subject to ongoing debate. During the last decade reconstructions of paleo-environmental conditions and the topographic evolution of mountain belts have increasingly relied on stable isotope proxies retaining the oxygen (δ18O) or hydrogen (δD) isotopic composition of ancient meteoric waters or carbon (δ13C) of vegetation. Intermontane basin sediments along the Puna of NW Argentina, the southern extension of the Altiplano-Puna Plateau and the world's second largest plateau, record the eastward-directed lateral growth of the central Andes and the spatiotemporal impact of tectonism on hydrologic, sedimentary, and ecological changes through time. Here we reconstructed paleo-hydrological changes during a phase of major Andean uplift and orographic barrier formation (10-2 Ma) along the eastern flank of the Puna Plateau from a sedimentary sequence within the intermontane Angastaco basin of NW Argentina (25°45 S, 66 W). We use a unique array of stable water-isotope proxies in leafwaxes, pedogenic carbonates and hydrated volcanic glass. In addition we use vegetation-cover proxies based on stable C isotopes obtained from leaf-waxes and pedogenic carbonates. Lipid biomarker leafwax δD values range between -95 and -160 ‰ (VSMOW), and δ13C values from -23 to -36 ‰ (PDB). Pedogenic carbonate δ18O values range from 18 to 31 ‰ (VSMOW) and δ13C values vary between -4 to -17 ‰ (PDB), whereas volcanic glass δD values range from -71 to -95 ‰ (VSMOW). In combination, these proxies provide a precipitation - evapotranspiration record, which reveals the onset of the South American Low Level-Jet in NW Argentina at ~ 9 Ma and the presence of seasonally humid foreland conditions until 7 Ma, followed by orographic barrier formation upwind of the basin and rapid creation of

  17. Cave-dwelling invertebrates of the NW Mediterranean: silent victims of global warming?

    NASA Astrophysics Data System (ADS)

    Lejeusne, C.; Chevaldonné, P.

    2003-04-01

    Dark submarine caves constitute an extreme and fragmented habitat of the littoral zone. They present environmental conditions characterised by a complete absence of light and a strong oligotrophy, and then are inhabited by endemic and specialised species. However, the extremely fragmented and poorly resilient characteristics of these communities imply that they are more sensitive than any other littoral community to large-scale perturbations such as global warming. Global change induces a long term increase in water temperatures, but also shorter and more acute events such as those recorded in the NW Mediterranean during summers 1997 and 1999. During these two thermal anomalies, water temperatures of up to 24^oC reached 40m depth and below, during several weeks. Many sessile invertebrate species such as sponges, cnidarians and bivalves, were heavily affected. Consequences on NW Mediterranean caves were studied through mysids (Crustacea: Peracarida), especially Hemimysis genus. Since its discover, Hemimysis speluncola Ledoyer, 1963 had been the dominant endemic mysid in those caves, where it formed large and high-density swarms. However, consequently to the thermal anomalies, swarm density declined rapidly, leading to an almost complete disappearance of the species. This phenomenon was first recorded in the Marseille (France) area, but we show that it happened in most other NW Mediterranean regions. At the same time, another mysid Hemimysis margalefi Alcaraz, Riera &Gili, 1986 replaced H. speluncola in the caves. Comparative thermotolerance experiments between the two species revealed more eurythermal characteristics in H. margalefi and a better resistance to acute thermal stress. Because of the Mediterranean geography, the endemic H. speluncola, with distant fragmented populations and a low thermal tolerance cannot migrate to northern (colder) regions. It may therefore be doomed to disappear in the context of global change, with replacement by the more thermophile

  18. New Insight Into the Crustal Structure of the Continental Margin offshore NW Sabah/Borneo

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Franke, D.; Behain, D.; Meyer, H.

    2002-12-01

    The continental margin offshore NW Sabah/Borneo (Malaysia) has been investigated with reflection and refraction seismics, magnetics, and gravity during the recent cruise BGR01-POPSCOMS. A total of 4000 km of geophysical profiles has been acquired, thereof 2900 km with reflection seismics. The focus of investigations was on the deep water areas. The margin looks like a typical accretionary margin and was presumably formed during the subduction of a proto South China Sea. Presently, no horizontal movements between the two plates are being observed. Like in major parts of the South China Sea, the area seaward of the Sabah Trough consists of extended continental lithosphere which is characterised by a pattern of rotated fault blocks and half grabens and a carbonate platform of Early Oligocene to Early Miocene age. We found evidence that the continental crust also underlies the Sabah Trough and the adjacent continental slope, a fact that raises many questions about the tectonic history and development of this margin. The tectonic pattern of the Dangerous Grounds' extended continental crust can be traced a long way landward of the Sabah Trough beneath the sedimentary succession of the upper plate. The magnetic anomalies which are dominated by the magnetic signatures of relatively young volcanic features also continue under the continental slope. The sedimentary rocks of the upper plate, in contrast, seem to generate hardly any magnetic anomalies. Based on the new data we propose the following scenario for the development of the NW Sabah continental margin: Seafloor spreading in the present South China Sea started at about 30 Ma in the Late Oligocene. The spreading process separated the Dangerous Grounds area from the SE Asian continent and ceased in late Early Miocene when the oceanic crust of the proto South China Sea was fully subducted in eastward direction along the Borneo-Palawan Trough. During Lower and/or Middle Miocene, Borneo rotated counterclockwise and was

  19. GPR Surveys for Archaeological Investigation in a Bronze Age site from NW Portugal

    NASA Astrophysics Data System (ADS)

    Gonçalves, L.; Sampaio, H. A.; Bettencourt, A. M. S.; Alves, M. I. C.

    2012-04-01

    This work describes the use of Ground-penetrating Radar (GPR) surveys in the identification and mapping of subtle cultural remains, from Pego Late Bronze Age settlement, located near the city of Braga, in NW Portugal. Bronze Age settlements from NW Portugal are characterized by the presence archaeological structures such as storage pits, postholes and trenches. These subtle structures have a very low dielectric contrast, making them quite difficult to detect in GPR surveys. In the case of Pego Site, previous investigations using conventional archaeological techniques, during a rescue excavation, partially revealed a residential area, a necropolis, and a stockade foundation trench that encircle the whole settlement. Different GPR prospection approaches were performed using GSSI Sir 3000 System, with 400 MHz antennae, with the objective of identify and define the borders between the different areas of human occupation inside the settlement. For the GPR survey, a grid-based approach with closely spaced parallels transects was defined, covering different areas inside the site. A first survey was conducted with a pseudo-3D methodology, with 50 cm profile separation, followed by a second survey with a dense data acquisition methodology, with 10 cm profile separation. Processed two-dimensional GPR profiles and constructed amplituded-slice maps were produced and analysed. Wave velocities were determined by reflected wave methods and by Hyperbola-Fitting method. The background analysis of the archaeological and geological features of the site, integrated with the preliminary interpretation of GPR data (profiles and amplitude slice-maps) suggest the presence of flat graves, in the west part of the site, and storage pits, post holes and some small trenches, in the centre and north area of the settlement. This interpretation indicates that the settlement is individualized in two different areas, a necropolis and a residential area, such as the first archaeological study

  20. Structural Setting of Western Monferrato (Alps-Apennines Junction Zone, NW Italy)

    NASA Astrophysics Data System (ADS)

    Piana, Fabrizio

    2000-10-01

    New data on the structural setting of the Torino Hill and Western Monferrato domains provide a clearer picture of the kinematic evolution of the Alps-Apennines junction zone. In the Alps-Apennines junction, left-lateral underthrusting of Ligurian units below Alpine crust has often been invoked to explain the underthrusting of the Insubric domain and the NW-ward movement of the Adriatic indenter. A transpressive fault system (Rio Freddo Fault Zone) developed in the Monferrato epi-Ligurian succession is here understood as the surficial expression of a deep-seated thrust along which the Alpine metamorphic basement of the Torino Hill has overridden the Apenninic Ligurian nappes since the Paleogene up to Burdigalian. In the Western Monferrato the regional sinistral transpression differentiated separated crustal blocks during the Oligocene-early Miocene, and kilometer-thick successions were steepened by NNW-SSE faults that acted as reverse and/or left-lateral faults. Double-vergent (SE-NW) low-angle shear zones then cut the Rio Freddo Fault Zone in post-Langhian times. They have been here related with the eastward tectonic transport of the Torino Hill and relative Alpine crust toward the Monferrato domain, which occurred before the seismic line scale middle Miocene unconformity was established. This poses the problem of the exact age of this regional unconformity, which in our case should be at least Serravallian. Finally, the Monferrato and Torino Hill domains were coupled, and both were NW-ward translated by the Padan Thrust Front in the Pliocene. The youngest strike-slip and reverse faults of the Western Monferrato may be tear or compartmental faults that partitioned the Padan Thrust motion, whose propagation could be controlled by pre-middle-Miocene tectonic structures. The structural complexity of the study area is here understood as the inheritance of deep crosscutting regional structures that forced the convergent structural units of the Alpine and Insubric

  1. The state of Lake Superior in 1992

    USGS Publications Warehouse

    Hansen, Michael J.

    1994-01-01

    The Lake Superior fish community in 1992 is substantially different than it was a half century ago and is far from a state desired by management agencies. Fish-community objectives were established for Lake Superior in response to A Joint Strategic Plan for Management of Great Lakes Fisheries (Great Lakes Fishery Commission 1980) and are the template for this report on the state of the lake. Reporting on progress toward meeting stated goals and objectives will focus attention on critical fishery issues and enhance understanding among fishery- and environmental-management agencies, political bodies, and the public.

  2. Common plankton of Twin Lakes, Colorado

    SciTech Connect

    Lieberman, D.M.

    1983-02-01

    A series of studies is being performed to evaluate the effects of the Mt. Elbert Pumped-Storage Powerplant on the ecology of Twin Lakes. Twin Lakes are a pair of connected dimictic lakes, formed as the result of glacial action on alluvial deposits. This report presents a taxonomic species study of the common plankton collected since 1974 from Twin Lakes. A total of 11 zooplankters and 14 phytoplankters were identified from the limnetic zone of Twin Lakes and the associated Mt. Elbert Forebay. The four divisions of zooplankton included four species of Rotifera (rotifer), three species of Copepoda (copepod), three species of Cladocera (cladoceran), and one species of Mysidacea (opossum shrimp).

  3. Evaluation of offshore stocking of Lake Trout in Lake Ontario

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.; Strang, T.G.; Lantry, J.R.; Connerton, M.J.; Schanger, T.

    2011-01-01

    Restoration stocking of hatchery-reared lake trout Salvelinus namaycush has occurred in Lake Ontario since 1973. In U.S. waters, fish stocked through 1990 survived well and built a large adult population. Survival of yearlings stocked from shore declined during 1990–1995, and adult numbers fell during 1998–2005. Offshore stocking of lake trout was initiated in the late 1990s in response to its successful mitigation of predation losses to double-crested cormorants Phalacrocorax auritus and the results of earlier studies that suggested it would enhance survival in some cases. The current study was designed to test the relative effectiveness of three stocking methods at a time when poststocking survival for lake trout was quite low and losses due to fish predators was a suspected factor. The stocking methods tested during 2000–2002 included May offshore, May onshore, and June onshore. Visual observations during nearshore stockings and hydroacoustic observations of offshore stockings indicated that release methods were not a direct cause of fish mortality. Experimental stockings were replicated for 3 years at one site in the southwest and for 2 years at one site in the southeast. Offshore releases used a landing craft to transport hatchery trucks from 3 to 6 km offshore out to 55–60-m-deep water. For the southwest site, offshore stocking significantly enhanced poststocking survival. Among the three methods, survival ratios were 1.74 : 1.00 : 1.02 (May offshore : May onshore : June onshore). Although not statistically significant owing to the small samples, the trends were similar for the southeast site, with survival ratios of 1.67 : 1.00 : 0.72. Consistent trends across years and sites indicated that offshore stocking of yearling lake trout during 2000–2002 provided nearly a twofold enhancement in survival; however, this increase does not appear to be great enough to achieve the 12-fold enhancement necessary to return population abundance to restoration

  4. Walleye in Lake Erie and Lake St. Clair

    USGS Publications Warehouse

    Nepszy, S.J.; Davies, D.H.; Einhouse, D.; Hatch, R.W.; Isbell, G.; MacLennan, D.; Muth, K.M.

    1991-01-01

    The history and current status of walleye (Stizostedion vitreum vitreum) stocks in Lake Erie and Lake St. Clair are reviewed in relation to their exploitation by commercial and recreational fishermen, environmental factors, rehabilitation efforts, and community dynamics. Management initiatives and stock recovery under these processes are outlined. After the collapse of the fishery in 1957, the highly productive walleye stock of western Lake Erie remained depressed through the 1960s, while the eastern basin stock remained stable. Closure of the fishery for walleye from 1970-73 because of mercury contamination provided an opportunity for the development of an international interagency management plan. With quota management, the walleye stock in western Lake Erie responded well to limited exploitation, steadily increased, and expanded its range. As population expanded, growth began to decline and was more apparent in the young-of-the-year (YOY) in the 1970s, and in older walleye in the late 1970s and 1980s. At the turn of the century, commercial harvest of walleye in Lake St. Clair ranged from 12-127 tonnes annually. A relatively stable period from 1910-59 was followed by significantly increased harvests (100-150 t) in 1959-65. This increase was a result of increased commercial exploitation as well as an increased abundance of walleye. After the mercury contamination problem of 1970, angling effort and harvest was reduced but then gradually increased in Ontario waters from 37 t in 1973 to 62 t in 1988. The increased mean age of the stock during the early 1970s was due to a few strong year-classes (1970, 1972, and 1974) as well as a period of stable or reduced catch per unit effort. With the current mean age not reduced significantly, the stocks of walleye should continue to provide good yields.

  5. Holocene lake salinity changes in the Wimmera, southeastern Australia, provide evidence for millennial-scale climate variability

    NASA Astrophysics Data System (ADS)

    Kemp, Justine; Radke, Lynda C.; Olley, Jon; Juggins, Steve; De Deckker, Patrick

    2012-01-01

    Palaeosalinity records for groundwater-influenced lakes in the southwest Murray Basin were constructed from an ostracod-based, weighted-averaging transfer function, supplemented with evidence from Campylodiscus clypeus (diatom), charophyte oogonia, Coxiella striata (gastropod), Elphidium sp. (foraminifera), Daphniopsis sp. ephippia (Cladocera), and brine shrimp (Parartemia zietziana) faecal pellets, the δ18O of ostracods, and > 130 μm quartz sand counts. The chronology is based on optically stimulated luminescence and calibrated radiocarbon ages. Relatively wet conditions are marked by lower salinities between 9600 yr and 5700 yr ago, but mutually exclusive high- and low-salinity ostracod communities suggest substantial variability in effective precipitation in the early Holocene. A drier climate was firmly in place by 4500 yr and is marked at the groundwater-dominated NW Jacka Lake by an increase in aeolian quartz and, at Jacka Lake, by a switch from surface-water to groundwater dominance. Short-lived, low-salinity events at 8800, 7200, 5900, 4800, 2400, 1300 and 400 yr are similar in timing and number to those recorded on Australia's southern continental shelf, and globally, and provide evidence for the existence of the ~ 1500-yr cycle in mainland southern Australia. We surmise that these are cool events associated with periodic equatorward shifts in the westerly wind circulation.

  6. The Hill of Six Lakes revisited: new data and re-evaluation of a key Pleistocene Amazon site

    NASA Astrophysics Data System (ADS)

    D'Apolito, Carlos; Absy, Maria Lúcia; Latrubesse, Edgardo M.

    2013-09-01

    The new analyses of a sedimentary record of Lake Pata in the Hill of Six Lakes, in NW Amazon and its correlation with other Quaternary proxy records in the region provide new insights regarding the vegetation and climate of the lowland forest during the Last Glacial. Despite what has been reported previously in the literature, the sedimentary and pollen records are not continuous. The hill remained forested; however, clear signals of structural change are seen in the record, which indicate that the area experienced a significantly drier climate during the Last Glacial Maximum (LGM). The herbs and taxa that are known to be more dominant in seasonally dry forests were all more abundant during the glacial part of the record, and the cool-adapted elements were mixed with warm lowland elements, which indicates a temperature depression. A comparison of the palaeoecological data with other regional geoenvironmental records of the Upper Negro River basin and other areas of the Amazon provides additional support for a cooler and more seasonal environment during the middle Pleniglacial, which then became drier during the LGM. A “wet” LGM is strongly refuted; therefore, the palaeoclimatic and ecological models that used the previous proxy data from Six Lakes to sustain “wet” conditions and a “continuous forest record” during the LGM to reconstruct the palaeoenvironmental conditions in the Amazon should be reviewed.

  7. Hydrology, water quality, and nutrient loads to Lake Catherine and Channel Lake, near Antioch, Lake County, Illinois

    USGS Publications Warehouse

    Kay, Robert T.; Johnson, Gary P.; Schrader, David L.

    2000-01-01

    From April 21, 1998, through April 30, 1999, the U.S. Geological Survey, in cooperation with the Fox Waterway Agency, conducted an investigation designed to characterize the hydrology, water quality, hydrologic budget, sediment budget, and nutrient budget of Lake Catherine and Channel Lake, Lake County, Illinois. These lakes are the northernmost lakes of the Fox Chain of Lakes. Lake Catherine and Channel Lake are divided into two basins by a submerged ridge but are continuous at the surface. The lakes are marginally to moderately eutrophic. Lake Catherine and Channel Lake have a combined volume of 7,098 acre-feet at a stage of about 736.5 feet above sea level. Lake Catherine and Channel Lake are subject to thermal stratification. Although most of the water in the lakes is well oxidized, nearly anoxic conditions were present at the bottom of Lake Catherine and Channel Lake during part of the summer in 1998. Water enters Lake Catherine and Channel Lake as inflow from surface water in the watershed (61.9 percent), inflow through the State Highway 173 bridge openings (20.7 percent), direct precipitation (8.2 percent), inflow from storm drains (7.2 percent), and inflow of ground water (2.0 percent). Water exits Lake Catherine and Channel Lake as outflow through the State Highway 173 bridge openings (87.8 percent), evaporation (7.2 percent), and as outflow to ground water (5.0 percent). About 5,200 pounds of phosphorus and 107,200 pounds of nitrogen compounds were added to the lakes during the period of investigation. Phosphorus compounds were derived from primarily internal regeneration (40.2 percent), inflow from surface water in the watershed (30.9 percent), inflow from storm drains (12.5 percent), and inflow through the State Highway 173 bridge openings (9.8 percent). Inflowing ground water, waterfowl excrement, precipitation, and atmospheric deposition of particulate matter account for 6.6 percent of the phosphorus load. Nitrogen was derived from inflow of surface

  8. 12. Photographic copy of copy of Twin Lakes Outlet Works ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photographic copy of copy of Twin Lakes Outlet Works construction drawing dated January 15, 1951. Drawn by W.A. Doe for the Twin Lakes Reservoir and Canal Co. (copy in possession of Bureau of Reclamation, location of original unknown) 'AS CONSTRUCTED' PLANS OF 1949-50, REHABILITATION OF TWIN LAKES RESERVOIR OUTLET WORKS, DETAILS OF DISCHARGE BASIN. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  9. 11. Photographic copy of copy of Twin Lakes Outlet Works ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Photographic copy of copy of Twin Lakes Outlet Works construction drawing dated January 15, 1951. Drawn by W.A. Doe for the Twin Lakes Reservoir and Canal Co. (copy in possession of Bureau of Reclamation, location of original unknown) 'AS CONSTRUCTED' PLANS OF 1949-1950, REHABILITATION OF TWIN LAKES RESERVOIR OUTLET WORKS, DETAILS OF UPSTREAM WING WALLS. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  10. Hydrology of Lake Tohopekaliga, Osceola County, Florida

    USGS Publications Warehouse

    Phelps, G.G.

    1982-01-01

    Lake Tohopekaliga, one of the major lakes in central Florida, provides flood control in the upper Kissimmee River basin, recreation for fishermen and boaters, water for live-stock, esthetic surroundings for homesites, and serves as a receiving body for treated effluent from municipal sewage treatment plants. The purpose of this map report is to provide a general reconnaissance of the lake, based primarily on existing geologic , hydrologic and water-quality data. The lake has a surface area of about 30 square miles and a mean depth of about 5 feet. Maximum depth measured was about 13 feet. Inflow to the lake comes from Shingle Creek and St. Cloud canal and outflow is through the South-port canal. Regulation of lake levels for flood control began in the early 1960 's and has resulted in a decrease in the range of lake stage of about 3 feet. Concentrations of pesticide residues in lake bottom sediments do not appear to have increased from 1972 to 1980. The lake has abundant aquatic vegetation, the amount and extent of which varies with fluctuating water levels. Water-quality data collected between 1954-77 are summarized in the report and additional data collected in 1980 are also shown. The range of plant nutrient concentrations measured in May 1980 are: Total organic nitrogen 0.71-2.2 milligrams per liter. Most water-quality parameters vary from one area of the lake to another because of restricted areal circulation due to the shape of the lake. (USGS)

  11. Lake fisheries need lamprey control and research

    USGS Publications Warehouse

    Moffett, James W.

    1953-01-01

    Since 1921, when the first sea lamprey was recorded from Lake Erie, concern about this parasite in the Great Lakes above Niagara Falls, where previously it had never occurred, grew successively. At first, the concern was shared only in scientific circles, but as the parasite continued its persistent and rapid spread throughout the upper Great Lakes this concern was voiced by state conservation departments, the U.S. Fish and Wildlife Service, and interested fishermen. Catches of lake trout especially, and other species secondarily, began to fall below anything representing normal fluctuations in abundance. The fishing industry on Lake Huron and Lake Michigan became extremely concerned due to the fact that income was diminishing greatly. Producers on Lake Superior were fearful that the same decline in production would soon characterize their fishery.

  12. Dissolved Oxygen Levels in Lake Chabot

    NASA Astrophysics Data System (ADS)

    Sharma, D.; Pica, R.

    2014-12-01

    Dissolved oxygen levels are crucial in every aquatic ecosystem; it allows for the fish to breathe and it is the best indicator of water quality. Lake Chabot is the main backup water source for Castro Valley, making it crucial that the lake stays in good health. Last year, research determined that the water in Lake Chabot was of good quality and not eutrophic. This year, an experiment was conducted using Lake Chabot's dissolved oxygen levels to ensure the quality of the water and to support the findings of the previous team. After testing three specifically chosen sites at the lake using a dissolved oxygen meter, results showed that the oxygen levels in the lake were within the healthy range. It was then determined that Lake Chabot is a suitable backup water source and it continues to remain a healthy habitat.

  13. Water-quality and lake-stage data for Wisconsin lakes, water year 1996

    USGS Publications Warehouse

    ,

    1997-01-01

    The purpose of this report is to provide information about the physical and chemical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected includes measurements of lake stage and in-lake water quality. Graphs of Secchi depths, surface totalphosphorus and chlorophyll-a concentrations versus time are included for lakes with two or more years of data. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, drainage area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in another volume: "Water Resources Data-Wisconsin, 1996."

  14. Water-quality and lake-stage data for Wisconsin lakes, water year 1994

    USGS Publications Warehouse

    Field, S.J.; Elder, J.F.; Garn, H.S.; Goddard, G.L.; Kammerer, P.A.; Olson, D.L.; Robertson, D.M.; Rose, W.J.

    1995-01-01

    The purpose of this report is to provide information about the physical, che-nical, and biological characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected includes measurements of lake stage and in-lake water quality. Graphs of Secchi depths, and total-phosphorus and chlorophyll-a concentrations versus time are included for lakes with two or more years of data. Descriptive information for each lake includes location of the lake, drainage area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in two other volunres: "Water Resources Data-Wisconsin, 1994, St. Lawrence River Basin" (Volume 1) and "Water Resources Data-Wisconsin, 1994, Upper Mississippi River Basin" (Volume 2). 

  15. Geology of central Lake Michigan

    SciTech Connect

    Wold, R.J.; Paull, R.A.; Wolosin, C.A.; Friedel, R.J.

    1981-09-01

    The geology beneath Lake Michigan between 43/sup 0/00' and 44/sup 0/00'N and between 86/sup 0/30' and 87/sup 0/40' W is interpreted from a synthesis of 1,700 km of continuous seismic reflection profile data, bathymetry, grab samples, and onshore surface and subsurface information. The continuous seismic reflection profiles and bathymetry provided information for maps of unconsolidated sediment thickness and Paleozoic bedrock topography. Two structural-stratigraphic cross sections of the study area were constructed by utilizing a composite subsurface-surface section for eastern Wisconsin and two control wells in western Michigan. The cross sections, grab samples previously described in the literature, the bedrock topographic map, and published maps were used to construct a Paleozoic geologic map for central Lake Michigan. Rocks from Middle Silurian through Early Mississippian age form subcrops beneath the study area, whereas rocks of Early Silurian, Ordovician, and Late Cambrian age are present at greater depth. The Upper Cambrian rocks unconformably overlie Precambrian igneous and metamorphic rocks. The structural-stratigraphic cross sections also allow speculation about the petroleum potential beneath Lake Michigan. The possibility of oil occurrences within the Silurian is enhanced by major east-west facies changes, and other horizons with promise are present in Devonian and Ordovician rocks. Although Michigan and Wisconsin laws currently prohibit petroleum exploration in Lake Michigan, it is an area with future potential.

  16. INTERACTIVE PIT LAKES 2004 CONFERENCE

    EPA Science Inventory

    This CD and the workshop provide a pit lakes forum for the exchange of scientific information on current domestic and international approaches, including arid and wet regions throughout the world. These approaches include characterization, modeling/monitoring, and treatment and r...

  17. Dinkey Lakes Roadless Area, California

    SciTech Connect

    Dodge, F.C.W.; Federspiel, F.E.

    1984-01-01

    The results of a mineral survey conducted in 1980, show that parts of the Dinkey Lakes Roadless Area have substantiated resource potential for tungsten and marble and probable resource potential for quartz crystal gemstones. A probable resource potential for geothermal energy exists in one small area. No potential for other metallic mineral or energy resources was identified in this study.

  18. The Source of Lake Wobegon

    ERIC Educational Resources Information Center

    Phelps, Richard P.

    2005-01-01

    John J. Cannell's late 1980s "Lake Wobegon" reports suggested widespread deliberate educator manipulation of norm-referenced standardized test (NRT) administrations and results, resulting in artificial test score gains. The Cannell studies have been referenced in education research since, but as evidence that high stakes (and not cheating or lax…

  19. Surgical lessons from the lake.

    PubMed

    Kothari, Shanu N

    2014-12-01

    After circumnavigating Lake Michigan during a sabbatical in the summer of 2011, the lessons learned from this experience and the surgical parallels between boating and life as a surgeon will be discussed. Topics will include the use of surgical checklists, teamwork and communication, leadership, and surgical mentorship. PMID:25440476

  20. The Taos Blue Lake Ceremony.

    ERIC Educational Resources Information Center

    Bodine, John J.

    1988-01-01

    Describes the Blue Lake Ceremony of the Taos Pueblo Indians of New Mexico. Reproduces the 1906 account of the ceremony by anthropologist Matilda Coxe Stevenson and notes modern verification and change. Discusses the importance of this annual August pilgrimage and initiation rite to the preservation of Taos culture. (SV)