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Sample records for aike maar lake

  1. Environment and climate of the last 51,000 years - new insights from the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO)

    NASA Astrophysics Data System (ADS)

    Zolitschka, B.; Anselmetti, F.; Ariztegui, D.; Corbella, H.; Francus, P.; Lücke, A.; Maidana, N. I.; Ohlendorf, C.; Schäbitz, F.; Wastegård, S.

    2013-07-01

    In this introductory paper we summarize the history and achievements of the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO), an interdisciplinary project embedded in the International Continental Scientific Drilling Program (ICDP). The stringent multiproxy approach adopted in this research combined with radiocarbon and luminescence dating provided the opportunity to synthesize a large body of hydrologically relevant data from Laguna Potrok Aike (southern Patagonia, Argentina). At this site, lake level was high from 51 ka until the early Holocene when the Southern Hemisphere Westerlies (SHW) were located further to the north. At 9.3 ka cal. BP the SHW moved southward and over the latitude of the study area (52°S) causing a pronounced negative water balance with a lake level decrease of more than 50 m. Two millennia later, the SHW diminished in intensity and lake level rose to a subsequent maximum during the Little Ice Age. Since the 20th century, a strengthening of the SHW increased the evaporative stress resulting in a more negative water balance. A comparison of our data with other hydrological fluctuations at a regional scale in south-eastern Patagonia, provides new insights and also calls for better chronologies and high-resolution records of climate variability.

  2. Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

    2009-04-01

    Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of

  3. Origin and evolution of the Laguna Potrok Aike maar (Southern Patagonia, Argentina) as revealed by seismic data

    NASA Astrophysics Data System (ADS)

    Gebhardt, C.; de Batist, M. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2009-12-01

    Seismic reflection and refraction data provide insights into the sedimentary infill and the underlying volcanic structure of Laguna Potrok Aike, a maar lake situated in the Pali Aike Volcanic Field, Southern Patagonia. The lake has a diameter of ~3.5 km, a maximum water depth of ~100 m and a presumed age of ~770 ka. Its sedimentary regime is influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Multiproxy environmental reconstructions of the last 16 ka document that this terminal lake is highly sensitive to climate change. Laguna Potrok Aike has recently become a major focus of the International Continental Scientific Drilling Program and was drilled down to 100 m below lake floor in late 2008 within the PASADO project. The sediments are likely to contain a continental record spanning the last ca. 80 kyrs unique in the South American realm. Seismic reflection data show relatively undisturbed, stratified lacustrine sediments at least in the upper ~100 m of the sedimentary infill but are obscured possibly by gas and/or coarser material in larger areas. A model calculated from seismic refraction data reveals a funnel-shaped structure embedded in the sandstone rocks of the surrounding Santa Cruz Formation. This funnel structure is filled by lacustrine sediments of up to 370 m in thickness. These can be separated into two distinct subunits with low acoustic velocities of 1500-1800 m s-1 in the upper subunit pointing at unconsolidated lacustrine muds, and enhanced velocities of 2000-2350 m s-1 in the lower subunit. Below these lacustrine sediments, a unit of probably volcanoclastic origin is observed (>2400 m s-1). This sedimentary succession is well comparable to other well-studied sequences (e.g. Messel and Baruth maars, Germany), confirming phreatomagmatic maar explosions as the origin of Laguna Potrok Aike.

  4. Origin and age of the Lake Nyos maar, Cameroon

    USGS Publications Warehouse

    Lockwood, J.P.; Rubin, M.

    1989-01-01

    Lake Nyos occupies a young maar crater in the Precambrian granitic terrane of northwest Cameroon. The lake is partly surrounded by poorly consolidated, ultramafic nodule-bearing pyroclastic surge deposits that were explosively ejected from the Nyos crater at the time of its formation. Radiocarbon dates show that the maar probably formed about 400 years ago. Field evidence suggests that carbon dioxide could have been the principal volatile involved in the formation of the Nyos maar, and that the role of water may have been minor. The formation of the Nyos maar was preceded by a brief period of effusive basaltic volcanism, but the maar itself may have largely formed by cold, 'dry' explosive processes. Carbon dioxide may still be trapped interstitially in a diatreme inferred to underlie Lake Nyos; its gradual release into the waters of Lake Nyos may have set the stage for the tragic gas-release event of August 21, 1986. Only young maar lakes such as Nyos may pose a danger of future lethal gas releases. ?? 1989.

  5. Morphotectonic setting of maar lakes in the Campo de Calatrava Volcanic Field (Central Spain, SW Europe)

    NASA Astrophysics Data System (ADS)

    Martín-Serrano, A.; Vegas, J.; García-Cortés, A.; Galán, L.; Gallardo-Millán, J. L.; Martín-Alfageme, S.; Rubio, F. M.; Ibarra, P. I.; Granda, A.; Pérez-González, A.; García-Lobón, J. L.

    2009-12-01

    In the Campo de Calatrava Volcanic Field (CCVF, Central Spain), the eruption of Pliocene-Pleistocene maar craters into two clearly distinct types of pre-volcanic rocks allows the observation and comparison of hard-substrate and soft-substrate maar lakes. Hard-substrate maars formed when phreatomagmatic processes affected the jointed, Paleozoic igneous and metamorphic rocks (hard substrate), giving rise to funnel-like maar lake basins. Soft-substrate maars resulted from phreatomagmatic volcanic processes affecting poorly-consolidated Pliocene sediments, forming bowl-like maar lake basins. Pre-volcanic bedrock determined the post-eruptive lacustrine architecture in the craters and favored a higher preservation of hard-substrate maars in comparison to soft-substrate maars. This is because the hard-substrate maars, surrounded by a deep stable crater wall, are more capable of collecting sediments in their basins. These sediments could be preserved for longer than similar deposits in broad, shallow maars with a soft substrate. Ancient soft-substrate maars do not usually preserve their original morphology well and can be identified only by their lacustrine deposits. Carbonate lacustrine/palustrine deposits surrounding a bowl-like depression are the remnants of this second type of maar lake, and allow reconstruction of the original morphology of ancient soft-substrate maar craters. Geophysical (electrical tomography ground surveys) and geomorphologic-geologic mapping techniques were combined with fieldwork and facies analysis in order to locate and accurately characterize the Pliocene-Pleistocene soft-substrate maar volcanic structures of the CCVF.

  6. Multi-proxy dating of Holocene maar lakes and Pleistocene dry maar sediments in the Eifel, Germany

    NASA Astrophysics Data System (ADS)

    Sirocko, Frank; Dietrich, Stephan; Veres, Daniel; Grootes, Pieter M.; Schaber-Mohr, Katja; Seelos, Klemens; Nadeau, Marie-Josée; Kromer, Bernd; Rothacker, Leo; Röhner, Marieke; Krbetschek, Matthias; Appleby, Peter; Hambach, Ulrich; Rolf, Christian; Sudo, Masafumi; Grim, Stephanie

    2013-02-01

    During the last twelve years the ELSA Project (Eifel Laminated Sediment Archive) at Mainz University has drilled a total of about 52 cores from 27 maar lakes and filled-in maar basins in the Eifel/Germany. Dating has been completed for the Holocene cores using 6 different methods (210Pb and 137Cs activities, palynostratigraphy, event markers, varve counting, 14C). In general, the different methods consistently complement one another within error margins. Event correlation was used for relating typical lithological changes with historically known events such as the two major Holocene flood events at 1342 AD and ca 800 BC. Dating of MIS2-MIS3 core sections is based on greyscale tuning, radiocarbon and OSL dating, magnetostratigraphy and tephrochronology. The lithological changes in the sediment cores demonstrate a sequence of events similar to the North Atlantic rapid climate variability of the Last Glacial Cycle. The warmest of the MIS3 interstadials was GI14, when a forest with abundant spruce covered the Eifel area from 55 to 48 ka BP, i.e. during a time when also other climate archives in Europe suggested very warm conditions. The forest of this "Early Stage 3 warm phase" developed subsequently into a steppe with scattered birch and pine, and finally into a glacial desert at around 25 ka BP. Evidence for Mono Lake and Laschamp geomagnetic excursions is found in two long cores. Several large eruptions during Middle and Late Pleistocene (Ulmener Maar - 11,000 varve years BP, Laacher See - 12,900 varve years BP, Mosenberg volcanoes/Meerfelder Maar 41-45 cal ka BP, Dümpel Maar 116 ka BP, Glees Maar - 151 ka BP) produced distinct ash-layers crucial for inter-core and inter-site correlations. The oldest investigated maar of the Eifel is 40Ar/39Ar dated to the time older than 520 ka BP.

  7. Holocene flood stack from three Eifel maar lakes

    NASA Astrophysics Data System (ADS)

    Brunck, Heiko; Sirocko, Frank

    2015-04-01

    Lacustrine sediments are very sensitive to natural and anthropogenically enviromental changes. Thus, lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, we extend our flood record for MIS 2/3 to the entire Holocene up to recent years to get a complete flood stack for the last 60 000 years. The present study reconstructs paleo floods from event layers in the sediment, of Schalkenmehren Maar (SM3), Ulmen Maar (UM1) and Holzmaar (HM1) combined with recent gauge time-series. All three maar lakes has an inflow by a local stream. Accordingly the sedimentation rate is directly linked to runoff activity and the bioturbation was low so that event layers become visible, but varves are only preserved in lake Holzmaar. The maar sites are situated in the Eifel near to the town of Daun and were drilled in the ELSA (Eifel Laminated Sediment archive) project. The Eifel area is well suited to approximate Central European weather, because modern water level gauge data from Eifel rivers correlate with respective data from the Rhine (Wernli and Pfahl, 2009). Combined sedimentological, paleobotanical and geochemical data received from SM3, UM1 and HM1 builds the foundation of the 14C based chronology. The synchronisation of the record is controlled by tephra time markers and pollen. Both are used to align the main cores of the ELSA project and construct an integrated age model for the last 220 000 years [b2k] (Förster and Sirocko, 2014). For the extension of our MIS 2/3 flood stack we used the Laacher See Tephra (10 900 BC) as marker for the correlation with the Holocene cores. To study the flood events in detail, 10 cm long thin sections were used to distinguish flood layers from distal turbidites. Turbidites have a continuous grain size gradation; the grains size profile of flood events is in contrast characterized by several grain size maxima over the entire layer thickness. A flood event over several

  8. The recent activity of the lake Albano (Castelgandolfo, Italy) maar.

    NASA Astrophysics Data System (ADS)

    Funiciello, Renato; Giordano, Guido; de Rita, Donatella; Carapezza, Maria Luisa; Barberi, Franco

    Lake Albano is a complex maar that fed the last phases of Colli Albani volcanic activity. The study of several new stratigraphic sections opened by archeological excavations and civil works has revealed the existence of two previously unknown, primary explosive volcanic deposits, and of several lahar deposits, distributed mainly in the Ciampino plain. Morphological analysis, radiometric dating, the distribution of the early human settlements in the area and the revision of the ancient history and myths of Roma, are coherent in indicating that the activity of lake Albano is much younger than previously believed and extends into Holocene. Until the 4th century B.C. catastrophic exondations have occurred from the lowest rim of the lake, with lahar emplacement on the northern slope. The repetition of these phenomena was prevented by a drain-tunnel dug by the Romans. The overflows were possibly triggered by sudden injections, in the lake bottom, of hot and CO2-rich fluids that are certainly present underneath the volcano. The presence of several gas emission sites, the high CO2 flux in zones corresponding to structural highs of the carbonate basement, the existence of pressurised aquifers also at shallow depth and the reported sudden increase of water temperature and gas release in relation to earthquakes, indicate that a similar hazard persists nowadays.

  9. Geomicrobiological investigations in subsaline maar lake sediments over the last 1500 years

    NASA Astrophysics Data System (ADS)

    Vuillemin, Aurèle; Ariztegui, Daniel; The Pasado Science Team

    2013-07-01

    Living microorganisms inhabit every environment of the biosphere but only in the last decades their importance governing biochemical cycles in deep sediments has been widely recognized. Most investigations have been accomplished in the marine realm whereas there is a clear paucity of comparable studies in lacustrine sediments. One of the main challenges is to define geomicrobiological proxies that can be used to identify different microbial signals in the sediments. Laguna Potrok Aike, a maar lake located in Southeastern Patagonia, has an annually not stratifying cold water column with temperatures ranging between 4 and 10 °C, and most probably an anoxic water/sediment interface. These unusual features make it a peculiar and interesting site for geomicrobiological studies. Living microbial activity within the sediments was inspected by the first time in a sedimentary core retrieved during an ICDP-sponsored drilling operation. The main goals to study this cold subsaline environment were to characterize the living microbial consortium; to detect early diagenetic signals triggered by active microbes; and to investigate plausible links between climate and microbial populations. Results from a meter long gravity core suggest that microbial activity in lacustrine sediments can be sustained deeper than previously thought due to their adaptation to both changing temperature and oxygen availability. A multi-proxy study of the same core allowed defining past water column conditions and further microbial reworking of the organic fraction within the sediments. Methane content shows a gradual increase with depth as a result of the fermentation of methylated substrates, first methanogenic pathway to take place in the shallow subsurface of freshwater and subsaline environments. Statistical analyses of DGGE microbial diversity profiles indicate four clusters for Bacteria reflecting layered communities linked to the oxidant type whereas three clusters characterize Archaea

  10. Volcanology, history and myths of the Lake Albano maar (Colli Albani volcano, Italy)

    NASA Astrophysics Data System (ADS)

    De Benedetti, A. A.; Funiciello, R.; Giordano, G.; Diano, G.; Caprilli, E.; Paterne, M.

    2008-10-01

    The polygenetic Albano maar is the most recent centre of the Colli Albani volcano, located just few kilometres to the south-east of Roma. Presently the maar hosts a 167.5 m deep crater lake, the deepest in Europe. The maar is to be considered quiescent, as phreatic activity is documented throughout the Holocene. This paper illustrates the close relationships between the activity of the maar and the history of settlement in the Roman region as recorded in the geology, archaeology, history and legends of the area. Severe fluctuations of the groundwater table and catastrophic overflows of the Lake Albano from the maar rim had occurred prior to and after the early prehistoric settlements dated in the maar area at the Eneolithic times (ca. III millennium B.C.). Repeated lahars occurred along the northwestern slope of the maar filling in the paleodrainage network and forming a vast plain. Paleohydraulic analyses on fluvial and lahar deposits originated from the Holocene phreatic activity of the Albano maar indicate sediment-water flows in excess of hundreds of cubic metres per second. Absolute age determinations of the paleosoil underlying one of the most recent deposits of the lahar succession at 5800 ± 100 yr B.P. ( 14C CAL) are in perfect agreement with the age of the overlying Eneolithic age settlements. The last catastrophic overflow is described in the Roman literature as a consequence of the anger of Poseidon against the Romans in 398 B.C. for their war against the Etruscans. In 394 B.C. the Romans decided to prevent the repetition of such events by the excavation through the maar crater wall of a 1.5 km long drain tunnel, which is still operational, keeping the lake 70 m below the lowest point of the maar rim. This tunnel drain may be regarded as the first prevention device for volcanic hazard in history and shows an unprecedented development of the engineering technology under the pressure of hazard perception. The surprising and still largely unknown results

  11. Multidisciplinary characterisation of sedimentary processes in a recent maar lake (Lake Pavin, French Massif Central) and implication for natural hazards

    NASA Astrophysics Data System (ADS)

    Chapron, E.; Albéric, P.; Jézéquel, D.; Versteeg, W.; Bourdier, J.-L.; Sitbon, J.

    2010-09-01

    Sedimentation processes occurring in the most recent maar lake of the French Massif Central (Lake Pavin) are documented for the first time based on high resolution seismic reflection and multibeam bathymetric surveys and by piston coring and radiocarbon dating on a sediment depocentre developed on a narrow sub aquatic plateau. This new data set confirms the mid Holocene age of maar lake Pavin formation at 6970±60 yrs cal BP and highlights a wide range of gravity reworking phenomena affecting the basin. In particular, a slump deposit dated between AD 580-640 remoulded both mid-Holocene lacustrine sediments, terrestrial plant debris and some volcanic material from the northern crater inner walls. Between AD 1200 and AD 1300, a large slide scar mapped at 50 m depth also affected the southern edge of the sub aquatic plateau, suggesting that these gas-rich biogenic sediments (laminated diatomite) are poorly stable. Although several triggering mechanisms can be proposed for these prehistoric sub-aquatic mass wasting deposits in Lake Pavin, we argue that such large remobilisation of gas-rich sediments may affect the gas stability in deep waters of meromictic maar lakes. This study highlights the need to further document mass wasting processes in maar lakes and their impacts on the generation of waves, favouring the development of dangerous (and potentially deadly) limnic eruptions.

  12. Climatic change evidence and lacustrine waves from maar lakes, Germany

    SciTech Connect

    Zolitschka, B.

    1992-01-01

    Annually laminated, non-glacial lake sediments from Lake Holzmaar (Eifel, western Germany) were investigated using large {open_quotes}Merkt{close_quotes} thin sections. The absolute age of varve intervals with variations in thickness and composition were correlated to climatic changes recorded by glacier fluctuations in the Alps. Back to 8800 years VT (vuarve time = varve years before 1950) glacier advances coincide with sedimentation rate minima; prior to 8800 years VT they coincide with sedimentation rate maxima. The early and middle Holocene sediments suggest a periodicity of about 1000 years for cold/warm cycles. A sequence of 512 varve-thickness measurements was subjected to spectral analysis. These provide apparent evidence for a 11-year sun-spot cycle. 30 refs., 3 fig.

  13. The potential for catastrophic dam failure at Lake Nyos maar, Cameroon

    USGS Publications Warehouse

    Lockwood, J.P.; Costa, J.E.; Tuttle, M.L.; Nni, J.; Tebor, S.G.

    1988-01-01

    The upper 40 m of Lake Nyos is bounded on the north by a narrow dam of poorly consolidated pyroclastic rocks, emplaced during the eruptive formation of the Lake Nyos maar a few hundred years ago. This 50-m-wide natural dam is structurally weak and is being eroded at an uncertain, but geologically alarming, rate. The eventual failure of the dam could cause a major flood (estimated peak discharge, 17000 m3/s) that would have a tragic impact on downstream areas as far as Nigeria, 108 km away. This serious hazard could be eliminated by lowering the lake level, either by controlled removal of the dam or by construction of a 680-m-long drainage tunnel about 65 m below the present lake surface. Either strategy would also lessen the lethal effects of future massive CO2 gas releases, such as the one that occurred in August 1986. ?? 1988 Springer-Verlag.

  14. Extreme events in the sedimentary record of maar Lake Pavin: Implications for natural hazards assessment in the French Massif Central

    NASA Astrophysics Data System (ADS)

    Chassiot, Léo; Chapron, Emmanuel; Di Giovanni, Christian; Albéric, Patrick; Lajeunesse, Patrick; Lehours, Anne-Catherine; Meybeck, Michel

    2016-06-01

    A set of sedimentary cores, high resolution swath bathymetry and subbottom profiler data provides new insights on sedimentary processes in meromictic maar Lake Pavin, France. Three sedimentary environments (i.e., littoral, plateau and basin) have been identified in the lake from sediment composition using bulk organic geochemistry and the analysis of hydroacoustic images. Various forms of rapidly deposited layers (RDLs) have been identified and radiocarbon dated. An up to date stratigraphy of sedimentary events matching coeval RDLs across the lake is presented and illustrates a wide range of natural hazards linked to Lake Pavin during the last 2000 years. In AD 600, a sudden lake outburst triggered a slump deposit along with a 9 m lake-level drop that drove shifts in sedimentary organic matter composition. Outside the lake, outburst flood deposits have been described downstream and provide sedimentary evidence for this event. The lake-level drop also favored the generation of gravity reworking processes, as shown by (1) a regional earthquake-triggered large slope failure on the plateau connected to a mass-wasting deposit in the basin dated to AD 1300, and (2) a succession of turbidites in AD 1825 and AD 1860 contemporaneous to two historic earthquakes, suggesting that this lake is sensitive to earthquakes with a minimum epicentral intensity of V. Finally, past observations of lake water color changes in AD 1783 and AD 1936, similar to reports in other meromictic lakes, match iron-rich deposits identified in maar lake sediments and suggest that Lake Pavin could have undergone limnic eruptions.

  15. Diatom diversity and paleoenvironmental changes in Laguna Potrok Aike, Patagonia: the ~ 50 kyr PASADO sediment record

    NASA Astrophysics Data System (ADS)

    Recasens, C.; Ariztegui, D.; Maidana, N. I.

    2012-12-01

    Laguna Potrok Aike is a maar lake located in the southernmost Argentinean Patagonia, in the province of Santa Cruz. Being one of the few permanent lakes in the area, it provides an exceptional and continuous sedimentary record. The sediment cores from Laguna Potrok Aike, obtained in the framework of the ICDP-sponsored project PASADO (Potrok Aike Maar Lake Sediment Archive Drilling Program), were sampled for diatom analysis in order to reconstruct a continuous history of hydrological and climatic changes since the Late Pleistocene. Diatoms are widely used to characterize and often quantify the impact of past environmental changes in aquatic systems. We use variations in diatom concentration and in their dominant assemblages, combined with other proxies, to track these changes. Diatom assemblages were analyzed on the composite core 5022-2CP with a multi-centennial time resolution. The total composite profile length of 106.09 mcd (meters composite depth) was reduced to 45.80 m cd-ec (event-corrected composite profile) of pelagic deposits once gaps, reworked sections, and tephra deposits were removed. This continuous deposit spans the last ca. 51.2 cal. ka BP. Previous diatomological analysis from the core catcher samples of core 5022-1D, allowed us to determine the dominant diatom assemblages in this lake and select the sections where higher temporal resolution was needed. Over 200 species, varieties and forms were identified in the sediment record, including numerous endemic species and others which can be new to science. Among these, a new species has been described: Cymbella gravida sp. nov. Recasens and Maidana. The quantitative analysis of the sediment record reveals diatom abundances reaching 460 million valves per gram of dry sediment, with substantial fluctuations through time. Variations in the abundance and species distribution point toward lake level variations, changes in nutrient input or even periods of ice-cover in the lake. The top meters of the record

  16. Multiproxy Paleoenvironmental Records Spanning the INTIMATE Timescale from Auckland Maar Lakes, New Zealand

    NASA Astrophysics Data System (ADS)

    Augustinus, Paul; D'Costa, Donna; Stephens, Tom; Atkin, Dan; Shane, Phil; Cochran, Ursula; Snowball, Ian; Nilsson, Andreas; Street-Perrott, Alayne; Davies, Sarah

    2010-05-01

    High-resolution Late Quaternary paleoclimate archives are preserved in the lake sediment records contained in several maar craters from the Auckland region in northern New Zealand. Tephrochronology, AMS 14C and Ar/Ar -based chronostratigraphies were developed with several lakes containing laminated sediment records spanning much of the last glacial cycle. A multi-proxy approach was taken to construct a reliable record of local and regional paleoenvironments including: pollen and diatom paleoecology, environmental magnetism, grain size, XRF geochemistry, TOC, TN, TS, organic matter δ13C, δ15N and δD, as well as δ18O in biogenic silica. Pollen and diatom analysis of records spanning the last ca 60 ka show marked vegetation changes that reflect orbital forcing, although diatoms suggest significant hydrological changes that are not reflected in the pollen. Reduction of forest with expansion of grass and shrublands at the start of the LGM (29 ka BP), is accompanied by cool, dry and windy conditions, although the situation is complex with multiple brief warmer phases punctuating the LGM. Post-glacial warming commenced ca 17.9 ka BP and is reflected in several proxies, although the pollen record does not display the marked changes displayed in many of the other proxies during the LGIT and Holocene. Some of the inferred environmental changes are similar to the nature and timing of short-duration events during the last glacial cycle from the North Atlantic region, although others appear to reflect a southern polar forcing. The multi-proxy approach used has produced one of the most complete, well-dated and high-resolution paleoenvironmental records spanning the INTIMATE timescale from the mid-latitude Southern Hemisphere with implications for the nature, timing and forcings of climate change in the Southwest Pacific region.

  17. Reconstructing Late Holocene Climate Variability in North East China From Varved Maar Lake Sediments

    NASA Astrophysics Data System (ADS)

    Panizzo, V. N.; Mackay, A. W.; Rioual, P.; Chu, G.; Leng, M. J.

    2008-12-01

    Reconstructing climatic variability over the past c. 2 ka years is recognised as a key PAGES timeframe (focus 2). However few high-resolution records exist from the climate sensitive region of N) China which receives the majority of its precipitation from the east Asian summer monsoon (EASM). Interactions between the EASM and the global climate system have great resonance. Such examples include how the EASM responded to changes in climate over the documented e.g. "Medieval Warm Period" (c. AD 900 - 1300), "Little Ice Age" (c. AD 1350-1850) and recent warming. At present, literature remains contradictory to such environmental changes in NE China over this time-frame due to poor chronological control, low resolution of existing studies and even due to the inexact terminology of these climatic periods. Xiaolongwan Lake (XLW) is a small, closed, maar lake located in the Long Gang Volcanic Field, NE China (42°18'N; 126°19'E). It is at an elevation of 655 m a.s.l. with a maximum depth of 15 m. A varve chronology has been created for a 143 cm composite core (2 cores collected in 2006), and here we present diatoms and organic geochemistry (δ13C, TOC, C/N) evidence for environmental change over the past c. 2 ka years. Results show a gradual change in diatom species, moving from a composition where opportunistic species (e.g. Achnanthidium minutissimum) dominate (between c. 100 BC to 500 years AD) at the beginning of the record to one comprised of benthic/epiphytic species (e.g. Staurosira construens var venter, Punctastriata discoidea, Gomphonema parvulum). The introduction after c. 1850 years AD of the planktonic diatom species, Discotella woltereckii, not previously seen in the record, coincides with recent warming. This may be a response to changing limnological conditions, such as decreasing duration of lake ice-cover. Bulk organic δ13C results conducted on a short core collected from XLW in summer 2007, show that over the past c. 350 years there is a distinct

  18. 40Ar/39Ar laser probe evidence concerning the age and associated hazards of the Lake Nyos Maar, Cameroon

    USGS Publications Warehouse

    Dalrymple, G.B.; Lockwood, J.P.

    1990-01-01

    The waters of Lake Nyos are impounded by a fragile natural dam composed of pyroclastic rocks ejected during the formation of the lake crater (maar). Lateral erosion of this dam has reduced its width from over 500 m to only 45 m. Published whole-rock K-Ar ages of about 100 ka on juvenile basalt from the dam suggests that erosion has been slow and that the dam poses no imminent threat. New apparent 40Ar/39Ar ages of 1.4 to 232 Ma on xenocrystic K-feldspar contained in the basalt show that the xenocrysts, whose source is the 528-Ma crystalline basement, are carriers of inherited radiogenic 40Ar and would cause the whole-rock K-Ar ages to be too old. The best estimate for the age of the maar is provided by a 14C age of 400 ?? 100 yr BP on charcoal from the base of the dam. This young age indicates that the dam is eroding at a relatively rapid rate; its failure, perhaps within a few decades, would result in a major flood and imperil thousands of people living downstream in Cameroon and eastern Nigeria. ?? 1990 Kluwer Academic Publishers.

  19. Rock-magnetic signature of precipitation and extreme runoff events in south-eastern Patagonia since 51,200 cal BP from the sediments of Laguna Potrok Aike

    NASA Astrophysics Data System (ADS)

    Lisé-Pronovost, A.; St-Onge, G.; Gogorza, C.; Jouve, G.; Francus, P.; Zolitschka, B.

    2014-08-01

    A 106-m long sediment sequence from the maar lake Laguna Potrok Aike in southern Patagonia was recovered in the framework of the International Continental Scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). About half of the sedimentary sequence is composed of mass movement deposits (MMDs) and the event-corrected record reaches back to 51,200 cal BP. Here we present a high-resolution rock-magnetic study revealing two sedimentary facies associated with MMDs and characterized by two different types of spurious gyroremanent magnetization (GRM) acquired during static alternating field demagnetization. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of GRM acquired during demagnetization of the natural remanent magnetization (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of a series of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetization of the isothermal remanent magnetization (IRM). Based on geological, limnological, stratigraphic and climatic evidence these layers are interpreted as reflecting pedogenic hematite and/or goethite brought to the lake by runoff events related to precipitation and permafrost melt. The pedogenic iron minerals mobilized from the catchment most likely settled out of suspension on top of MMDs after a rapid remobilization event. The series of runoff events corresponds to periods of increased lacustrine productivity in Laguna Potrok Aike and are coeval within the limit of the chronology to warm periods of the Last Glacial as recorded in Antarctica, the deglaciation in the mid-latitudes of the Southern Hemisphere and enhanced precipitation during the Early Holocene in southeastern

  20. Changes in mid to late Holocene monsoon strength in eastern Mexico inferred from high-resolution maar lake sediments

    NASA Astrophysics Data System (ADS)

    Bhattacharya, T.; Byrne, R.; Wogau, K.; Bohnel, H.

    2013-12-01

    Understanding the Holocene variation in central Mexico's summer precipitation can help identify the processes responsible for climatic change and clarify the role of climate in Mesoamerican cultural change. We present proxy results from Aljojuca, a maar lake in the Oriental-Serdan Basin in Mexico's Trans-Mexican Volcanic Belt. The 12 m sediment core from Aljojuca features a laminated, high-resolution proxy archive. A chronology established via radiocarbon dating shows a basal date of 6,200 cal. years B.P. We use fluctuations in pollen, elemental geochemistry, and the stable isotope ratios of authigenic carbonates to reconstruct the timing and duration of mid to late Holocene droughts in central Mexico. We compare these results with geochemical analyses of maar wall rocks and palynological analyses of modern moss polsters to strengthen our interpretations of proxy results. We interpret periods of aridity as periods of reduced summer precipitation and therefore decreased summer monsoon strength. Our results reveal evidence of a gradual decrease in monsoon strength from the mid to late Holocene. We also identify a multi-century dry period between 1,150 and 800 cal yr. BP, coinciding with the abandonment of the nearby fortified city of Cantona. Spatiotemporal analysis of this and other paleoclimatic records reveals region-wide evidence of this ';Terminal Classic' drought, although its timing is spatially heterogeneous. Our results represent one of the only high-resolution mid-Holocene records from the eastern Trans-Mexican Volcanic Belt.

  1. Whole genome sequences of a free-living Pseudomonas sp. strain ML96 isolated from a freshwater Maar Lake.

    PubMed

    Li, Xiuling; Blom, Jochen; Zeng, Yonghui

    2015-12-01

    A free living freshwater Pseudomonas strain ML96 was isolated from the Huguangyan Maar Lake in southern China. Genome sequencing of strain ML96 revealed a 4.7 Mb long draft genome consisting of 47 contigs with a G+C content of 64.8%. Its 16S and 23S rRNA gene sequences were 99.8% and 99.3% identical to those of its closest relative, Pseudomonas alcaligenes NBRC 14159, respectively. ML96's genome shared 73% orthologous CDS (3256/4457) with the genome of NBRC 14159. Comparative genomics analysis provide further insight into the diversity and evolution of aquatic Pseudomonas species, which may help enhance our understanding of this both environmentally and medically important group of bacteria.

  2. A late quaternary record of eolian silt deposition in a maar lake, St. Michael Island, western Alaska

    USGS Publications Warehouse

    Muhs, D.R.; Ager, T.A.; Been, J.; Bradbury, J.P.; Dean, W.E.

    2003-01-01

    Recent stratigraphic studies in central Alaska have yielded the unexpected finding that there is little evidence for full-glacial (late Wisconsin) loess deposition. Because the loess record of western Alaska is poorly exposed and not well known, we analyzed a core from Zagoskin Lake, a maar lake on St. Michael Island, to determine if a full-glacial eolian record could be found in that region. Particle size and geochemical data indicate that the mineral fraction of the lake sediments is not derived from the local basalt and is probably eolian. Silt deposition took place from at least the latter part of the mid-Wisconsin interstadial period through the Holocene, based on radiocarbon dating. Based on the locations of likely loess sources, eolian silt in western Alaska was probably deflated by northeasterly winds from glaciofluvial sediments. If last-glacial winds that deposited loess were indeed from the northeast, this reconstruction is in conflict with a model-derived reconstruction of paleowinds in Alaska. Mass accumulation rates in Zagoskin Lake were higher during the Pleistocene than during the Holocene. In addition, more eolian sediment is recorded in the lake sediments than as loess on the adjacent landscape. The thinner loess record on land may be due to the sparse, herb tundra vegetation that dominated the landscape in full-glacial time. Herb tundra would have been an inefficient loess trap compared to forest or even shrub tundra due to its low roughness height. The lack of abundant, full-glacial, eolian silt deposition in the loess stratigraphic record of central Alaska may be due, therefore, to a mimimal ability of the landscape to trap loess, rather than a lack of available eolian sediment. ?? 2003 University of Washington. Published by Elsevier Inc. All rights reserved.

  3. Holocene climate change and human impact, central Mexico: a record based on maar lake pollen and sediment chemistry

    NASA Astrophysics Data System (ADS)

    Park, Jungjae; Byrne, Roger; Böhnel, Harald; Garza, Roberto Molina; Conserva, Mariaelena

    2010-03-01

    This paper presents multiproxy (pollen, magnetic susceptibility, sediment chemistry) records from two maar crater lakes in the Valle de Santiago of Guanajuato, Mexico: Hoya San Nicolás and Hoya Rincon de Parangueo. Sediment cores from the two sites have basal dates of ca 11,600 and 9600 cal yr BP, respectively. The San Nicolás results show that the lake desiccated several times during the Holocene, and this resulted in the selective destruction of the less resistant pollen types. A comparative analysis of data from both sites indicates that during the earliest Holocene (ca 11,600-9000 cal yr BP) there were short term oscillations of wetter and drier climate; during the early Holocene (ca 9000-5700 cal yr BP) it was on average wetter; during the middle Holocene (ca 5700-3800 cal yr BP) drier; and during the middle to late Holocene (ca 3800-2200 cal yr BP) wetter. Increasing human disturbance during the late Holocene of environment obscures the climatic record. Agricultural activities in the area began as early as ca 5700 cal yr BP and intensified around 2400 cal yr BP.

  4. Rock magnetic studies on sediments from Erlongwan maar lake, Long Gang Volcanic Field, Jilin province, NE China

    NASA Astrophysics Data System (ADS)

    Frank, Ute

    2007-01-01

    Detailed rock magnetic investigations were carried out on two 23-m-long sediment cores from Erlongwan maar lake, NE China. The completely laminated sediment sequence of the lake is interrupted by 410 graded layers with thicknesses between 0.1 and 150 cm. Magnetite of PSD-size was identified as the main magnetic carrier mineral by temperature-dependent measurements of the saturation magnetization and determination of hysteresis parameters. The minerogenic components in the laminated sediments and the graded layers are nearly identical, and their rock magnetic characteristics reflect the prevailing conditions, anoxic or oxic, during deposition. The most reliable criteria for estimating the availability of oxygen is whether an increase in minerogenic influx is linked to a shift in the magnetic grain size spectrum to coarser (oxic) or finer (anoxic) grains. Comparison of different rock magnetic parameters indicative for magnetic grain size and coercitivity revealed, that the S-ratio which is known to reflect the presence of high coercive minerals, is grain size indicative in sediments with a monomineralic magnetic composition.

  5. A 1000-yr record of environmental change in NE China indicated by diatom assemblages from maar lake Erlongwan

    NASA Astrophysics Data System (ADS)

    Wang, Luo; Rioual, Patrick; Panizzo, Virginia N.; Lu, Houyuan; Gu, Zhaoyan; Chu, Guoqiang; Yang, Deguang; Han, Jingtai; Liu, Jiaqi; Mackay, Anson W.

    2012-07-01

    Past environmental changes based on diatom relative abundances have been inferred from the maar Lake Erlongwan in northeast China. The limnology of Lake Erlongwan is affected by the strongly seasonal regional climate. The composition of diatom assemblages, in turn, responds to changes in the seasonal duration of ice cover in winter, water-column turnover in spring and autumn, and thermal stratification in summer. Statistical analysis of the sedimentary diatom assemblages reveals three significant stratigraphic zones over the past 1000 yr. The highest abundance of the planktonic species Discostella species occurs between AD 1050 and 1400 and suggests an annual ice-free period of long duration and well-developed summer stratification of the water column. This planktonic diatom peak between ca. AD 1150 and 1200 suggests that this period was the warmest over the past 1000 yr. The interval between AD 1400 and 1800 is marked by a decline in planktonic diatoms and suggests shorter duration of the ice-free season, weaker water stratification and possibly generally cold conditions. After AD 1800 relative abundances of planktonic diatoms, including Puncticulata praetermissa and Asterionella formosa, increase again, which indicates lengthening of the duration of the annual ice-free period and a stronger overturn of the water column. All these data imply that the pattern of the seasons is different between the MWP and the 20th century.

  6. Assessing Magmatic Processes and Hazards at two Basaltic Monogenetic Centers: Volcan Jorullo, Mexico, and Blue Lake Maar, Oregon

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.; Cashman, K.; Wallace, P.; Delgado Granados, H.

    2007-05-01

    Although monogenetic basaltic volcanoes exhibit a wide variety of eruption styles, the origin of this diversity is poorly understood and often ignored when assessing volcanic hazards. To better understand magmatic processes and hazards associated with these eruptions, we have studied two monogenetic centers with differing behavior: Volcan Jorullo, a cinder cone in Mexico, and Blue Lake, a maar in the Oregon High Cascades. Although compositionally similar (medium-K basalt to basaltic andesite), their eruptive styles and products are quite different. Jorullo had violent strombolian eruptions that deposited alternating beds of ash and tephra, as well as lava flows. In contrast, Blue Lake exhibited initial phreatomagmatism that formed a 100m deep crater and produced surge deposits. This activity was followed by magmatic eruptions that produced deposits of tephra and bombs, but no lava flows. The diversity in eruptive style at these two centers reflects different magma ascent and crystallization processes, deduced using olivine-hosted melt inclusions. Jorullo melt inclusions trap variably degassed melts (0.5-5 wt% H2O; 0-1000 ppm CO2), with associated crystallization pressures that decrease from early (<4 kbars) to late (<100 bars) in the eruption. These data support the formation of a shallow storage region beneath the volcano that facilitated both crystallization and magma degassing, which is consistent with effusion of degassed lavas from the base of the cone throughout the eruption. In contrast, Blue Lake inclusions trap melts with a restricted range of volatiles (2.6-4 wt% H2O; 677-870 ppm CO2) corresponding to crystallization pressures of 2.2-3.2 kbars. This suggests that the magma feeding Blue Lake stalled in the upper crust and crystallized before ascending rapidly to the surface, without further crystallization of olivine or shallow storage. This is consistent with both the observed unstratified tephra deposits (indicating single rather than pulsatory eruptions

  7. New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany)

    NASA Astrophysics Data System (ADS)

    Lenz, Olaf K.; Wilde, Volker; Mertz, Dieter F.; Riegel, Walter

    2015-04-01

    The annually laminated oil shale from the Eocene maar lake at Messel (Federal State of Hessen, Germany) provides unique paleoenvironmental data for a time interval of ~640 ka during the Paleogene greenhouse phase. As a consequence of orbitally controlled changes in the vegetation in the vicinity of the lake, the lacustrine laminites can now be astronomically tuned. Dating is based on the short eccentricity amplitude modulations of the regional pollen rain and their correlation to the astronomical La2010a/La2010d solutions in combination with a revised 40Ar/39Ar age of a basalt fragment from a lapilli tuff section below the first lacustrine sediments. Depending on different newly suggested ages for the Fish Canyon sanidine used as monitor for neutron irradiation, the age for the eruption at Messel is between 48.27 ± 0.22 and 48.11 ± 0.22 Ma. This allows for the first time the exact correlation of a Paleogene lacustrine sequence to the marine record in Central Europe. The Messel oil shale becomes now slightly older than previously assumed and includes the Ypresian/Lutetian boundary that moves the base of the European Land Mammal Age Geiseltalian (MP 11) into the Lower Eocene. This opens a window for establishing an independent chronostratigraphic framework for Paleogene terrestrial records and their correlation to the marine realm. Furthermore, the study reveals that higher amounts of pollen from "wet" and thermophilous plants indicate less seasonal and more balanced precipitation and slightly higher temperatures during a well-expressed eccentricity minimum.

  8. Laguna Potrok Aike, Argentina: the first non-tropical environmental record in South America extending far beyond the Late-Glacial - a progress report

    NASA Astrophysics Data System (ADS)

    Zolitschka, B.; Anselmetti, F.; Ariztegui, D.; Corbella, H.; Francus, P.; Gebhardt, C.; Lücke, A.; Ohlendorf, C.; Schäbitz, F.; Pasado Science Team

    2009-04-01

    Within the framework of the ICDP-funded "Potrok Aike maar lake sediment archive drilling project" (PASADO) an international team of scientists carried out interdisciplinary research at the unique mid-Pleistocene (770 ka) maar lake of Laguna Potrok Aike in southern Patagonia (Province of Santa Cruz, Argentina). This lake is very sensitive to variations in southern hemispheric wind and pressure systems and thus holds a unique and continuous lacustrine record of climatic and ecological variability of global significance. Moreover, Southern Patagonia with its many active volcanoes is an ideal location to better understand the regional history of volcanism. These are two challenging geo-scientific themes that need to be tackled, especially as both of them have an increasing socio-economic relevance. Three months of drilling activities that finished last November 2008 were carried out by DOSECC from the drilling platform R/V "Kerry Kelts". More than 500 m of lacustrine sediments were recovered. This sedimentary archive will provide (1) new insights into the processes of regional back arc volcanism within the Pali Aike Volcanic Field itself as well as the more distant explosive volcanism of the Andean mountain chains; and, (2) high-resolution (decadal) quantitative climate and environmental reconstructions supported by multiple dating and stratigraphic correlations. Marine - ice core - terrestrial linkages will be emphasized as well as the incorporation of results from global climate modelling simulations for the last ca. 100 ka. The two drilled sites in the central deep basin of Laguna Potrok Aike have been selected based on four seismic surveys carried out between 2003 and 2005. Sediments were recovered at both drilled sites down to a subbottom depth of slightly more than 100 m using the GLAD800 drill rig with the hydraulic piston corer tool (HPC) at water depths varying between 95 and 100 m. The total core recovery is 94%. On-site core logging with the multi sensor

  9. Diagenetic effects on magnetic minerals in a Holocene lacustrine sediment core from Huguangyan maar lake, southeast China

    NASA Astrophysics Data System (ADS)

    Wu, Xudong; Wang, Yong; Bian, Liu; Shen, Ji

    2016-09-01

    Post-depositional reductive diagenesis usually results in partial or entire cleansing of the pristine palaeomagnetic signal, therefore, its intensity is important to be assessed for sediments that are in the purpose of retrieving palaeomagnetic information. Grain size, rock magnetic and geochemical studies on the entire core, along with scanning electron microscope observations and X-ray diffraction analyses for representative samples were carried out on a Holocene sediment core retrieved from the deep water part of Huguangyan maar lake (HGY), southeast China. The pristine magnetic mineral assemblage of the studied core is domianted by superparamagnetic (SP) and stable single domain titanomagnetite, and high coercivity minerals are not detectable. Based on down-core variations of the average grain size (MZ), total organic carbon (TOC), detrital elements (Al, Ti, Fe and Mn) and the concentration and mineralogy of magnetic minerals, the studied core could be divided into three subsections. The uppermost subsection is the least affected by diagenesis, with detrital titanomagnetite as the dominant magnetic mineral. This is owing to low TOC contents, but high detrital input generated by weak Asian summer monsoon intensity during the late Holocene. The intermediate subsection shows down-core progressively enhanced dissolution of detrital titanomagnetite, and concomitant formation of authigenic pyrite and siderite, which indicates down-core progressively enhanced diagenesis generated by down-core progressive increasing TOC content, but decreasing detrital input as the result of down-core progressively strengthened Asian summer monsoon intensity. The pristine magnetic mineral assemblage has been profoundly modified in the lowermost subsection. At certain positions of the lowermost subsection, detrital titanomagnetite has been even completely dissolved via diagenesis, giving place to authigenic pyrite and siderite. High TOC content, but low detrital input generated from

  10. Changements climatiques et variations du champ magnetique terrestre dans le sud de la Patagonie (Argentine) depuis 51 200 ans reconstitues a partir des proprietes magnetiques des sediments du lac Laguna Potrok Aike

    NASA Astrophysics Data System (ADS)

    Lise-Pronovost, Agathe

    Rock magnetism is influenced by climate and by the Earth's magnetic field. The goal of this thesis is to use the rock magnetic properties of the long sedimentary sequence from the lake Laguna Potrok Aike (106 m, 51200 cal BP) to derive paleomagnetic and paleoclimatic records in a key area of the Southern Hemisphere that is poorly documented. Laguna Potrok Aike (52°S, 70°W) is located in southeastern Patagonia (Argentina) in the path of the strong Southern Hemisphere westerly winds and in the source area of the dust deposited in Antarctica during Glacial periods. The lake geographical location is therefore ideal to reconstruct past changes in aeolian activity and climate changes in Patagonia. It is also a key location to reconstruct past changes of the geomagnetic field because the Southern Hemisphere is significantly under-documented relative to the Northern Hemisphere. In addition, the proximity of the South Atlantic Anomaly (SAA) as well as the Southern Hemisphere high flux lobes could allow identifying differences in the paleomagnetic field evolution in southern South America relative to the much more documented Northern Hemisphere. For his strong potential to provide high-resolution climatic, aeolian and paleomagnetic records beyond the last climatic transition, the maar lake Laguna Potrok Aike was drilled in the framework of the International scientific Continental Drilling Program (ICDP) for the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). In this thesis, high-resolution rock-magnetic and physical properties are used in order to reconstruct paleoclimate and paleomagnetic records from the southernmost part of South America. In the first chapter, the full-vector paleomagnetic record (inclination, declination and relative paleointensity) derived from the sediments of Laguna Potrok Aike. A grain size influence on the relative paleointensity record (NRM/ARM) was corrected using the median destructive field of the natural remanent

  11. Sedimentary record of polycyclic aromatic hydrocarbons in a sediment core from a maar lake, Northeast China: evidence in historical atmospheric deposition.

    PubMed

    Guan, Yu-Feng; Sun, Jian-Lin; Ni, Hong-Gang; Guo, Jian-Yang

    2012-09-01

    A maar lake is an excellent ecosystem to study the atmospheric deposition of pollutants, as its contaminants are primarily by atmospheric deposition. In this study, a sediment core from Sihailongwan Maar Lake, Northeast China, was collected and the historical atmospherically deposited polycyclic aromatic hydrocarbons (PAHs) were analyzed. The concentrations of TPAHs (the sum of the US EPA proposed 16 priority PAHs, excluding naphthalene and pyrene) ranged from 473.9 to 2289 ng g(-1) with a slow increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments. The input rate of TPAHs, especially that of PAH(9) (the sum of fluoranthene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(ah)anthrathene, and benzo(ghi)perylene), correlated well to the Chinese historical socioeconomic data. This indicates that sediment PAHs were mainly derived from human activities and PAH(9) can be regarded as a better indicator of the local socioeconomic development. Source identification suggested that PAHs were originated primarily from mixed sources (e.g., coal and biomass burning and petroleum combustion), except for perylene which was mostly of diagenetic origin. In addition, the down-core PAHs profile clearly illustrated that PAHs sources in Northeast China experienced a transformation from low- and moderate temperature to high-temperature combustion processes, especially after the late 1980s. Additionally, an ecological risk assessment using two redefined biological thresholds (TEQ(ERL) and TEQ(ERM)) indicated that most of the PAHs measured in the present sediment core would not cause an immediate toxic effect; only FLU and PHEN are a potential source of concern for biological impairment.

  12. Carbon sources and biogeochemical processes in Monticchio maar lakes, Mt Vulture volcano (southern Italy): New geochemical constrains of active degassing of mantle derived fluids

    NASA Astrophysics Data System (ADS)

    Caracausi, A.; Nuccio, P. M.; Favara, R.; Grassa, F.

    2012-04-01

    Since the catastrophic releases of carbon dioxide from the African volcanic lakes Nyos and Monoun in the 1980s, the scientific community draw attention towards all those crater lakes able to accumulate massive amount of CO2, which could be catastrophically released following overturn of their deep waters. This implies a quantification of the gas accumulation rate into the lakes and the knowledge of recharge processes and their evolution in time. In fact the gaseous recharge in a lake occurs at alarming rates, when an active degassing of hazardous nature volatiles occurs into the lakes and the structure and dynamic of the lake permit the accumulation of gases into the water. The Monticchio lakes, LPM and LGM, occupies two maar craters formed during the last volcanic activity of Mt. Vulture occurred ˜ 140 000 years ago. LPM is a permanently stratified lake, with a thick deep volume of stagnant water and a shallower layer affected by seasonal overturn. On the contrary LGM is a monomittic lake with a complete overturn of the water during winter time. The major dissolved volatiles are methane and CO2. Dissolved helium is in trace amounts and its isotopic signature ranges between 6.1 and 5.3 Ra (Ra is the atmospheric 3He/4He isotopic ratio). These values are within the range of those measured in the olivine fluid inclusions (both of mantle xenoliths and dispersed in the pyroclastics) of LPM maar ejecta. During three years of investigations we observed that dissolved methane in the deep waters of LGM drastically decreases in wintertime as consequence of the complete overturn of the water. The isotopic signature of methane in the deepest portions of LGM (both sediment and water) is quite stable with time and highlights a biogenic origin, being produced both by acetate fermentation and by CO2-reduction in variable proportions. In contrast, a higher contribution of methane produced via CO2 reduction characterizes sediments at shallower depths. At LPM, there is a great

  13. Rock-magnetic proxies of wind intensity and dust since 51,200 cal BP from lacustrine sediments of Laguna Potrok Aike, southeastern Patagonia

    NASA Astrophysics Data System (ADS)

    Lisé-Pronovost, Agathe; St-Onge, Guillaume; Gogorza, Claudia; Haberzettl, Torsten; Jouve, Guillaume; Francus, Pierre; Ohlendorf, Christian; Gebhardt, Catalina; Zolitschka, Bernd

    2015-02-01

    The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Located in the path of the Southern Hemisphere westerly winds and in the source region of dust deposited in Antarctica during Glacial periods, southern Patagonia is a vantage point to reconstruct past changes in aeolian activity. Here we use high-resolution rock-magnetic and physical grain size data from site 2 of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) in order to develop magnetic proxies of dust and wind intensity at 52°S since 51,200 cal BP. Rock-magnetic analysis indicates the magnetic mineral assemblage is dominated by detrital magnetite. Based on the estimated flux of magnetite to the lake and comparison with distal dust records from the Southern Ocean and Antarctica, kLF is interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale, when ferrimagnetic grain size and coercivity influence are minimal. Comparison to physical grain-size data indicates that the median destructive field of isothermal remanent magnetization (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension. Comparison with wind-intensity proxies from the Southern Hemisphere during the last Glacial period and with regional records from Patagonia since the last deglaciation including marine, lacustrine and peat bog sediments as well as speleothems reveals similar variability with MDFIRM up to the centennial time scale. MDFIRM is interpreted as a wind-intensity proxy independent of moisture changes for southeastern Patagonia, with stronger winds capable of transporting coarser magnetite bearing silts to the lake.

  14. Modern and subrecent spatial distribution and characteristics of sediment infill controlled by internal depositional dynamics, Laguna Potrok Aike (southern Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Kastner, S.; Ohlendorf, C.; Haberzettl, T.; Lücke, A.; Maidana, N. I.; Mayr, C.; Schäbitz, F.; Zolitschka, B.

    2009-04-01

    Situated in the dry steppe environment of south-eastern Patagonia the 100 m deep and max. 770 ka old maar lake Laguna Potrok Aike (51°58'S, 70°23'W) has a high potential as a palaeolimnological key site for the reconstruction of terrestrial palaeoclimate conditions. As this area is sensitive to variations in southern hemispheric wind and pressure systems the lake holds a unique lacustrine record of palaeoclimatic and palaeoecological variability. Depositional changes inferred from the lacustrine sediment sequence as well as subaerial and subaquatic lake level terraces provide detailed information about the water budget of the lake related to the variability of the Southern Hemispheric Westerlies. For this reason the lake was chosen as an ICDP drilling site in 2008 within the "Potrok Aike maar lake sediment archive drilling project" (PASADO). Based on high resolution multi-proxy investigations of the last 16,000 years carried out on a 18.9 m long sediment record (Haberzettl et al., 2007; Mayr et al., 2009; Wille et al., 2007) this study focuses on the understanding of internal depositional dynamics which control the characteristics and spatial distribution of the sediment infill of this lake. Furthermore, it provides information improving the accuracy of the interpretation of the long sediment record recovered within the PASADO project. A survey of the spatial sediment distribution was carried out in 2005 using 46 gravity cores of up to 49 cm length covering a range of water depths from 9 to 100 m. All 46 cores were scanned with X-ray fluorescence technique and for magnetic susceptibility with up to 1 mm spatial resolution. Using Ca and Ti as well as magnetic susceptibility data the cores were correlated and linked to the established age model (Haberzettl et al., 2005). As these parameters vary considerably and not consistently within the suite of littoral cores, a correlation prior to the 2005 sediment surface is solely based on cores from water depths exceeding

  15. A multi-proxy intercomparison of environmental change in two maar lake records from central Turkey during the last 14 ka

    NASA Astrophysics Data System (ADS)

    Roberts, C. Neil; Allcock, Samantha L.; Arnaud, Fabien; Dean, Jonathan R.; Eastwood, Warren J.; Jones, Matthew D.; Leng, Melanie J.; Metcalfe, Sarah E.; Malet, Emmanuel; Woodbridge, Jessie; Yiǧitbaşıoǧlu, Hakan

    2016-04-01

    Individual palaeoenvironmental records are a combination of regional-scale (e.g. climatic) and local factors. In order to separate these signals, we compare multiple proxies from two nearby maar lake records, on the assumption that common signals are due to regional-scale forcing. On the other side, we infer that residual signals are likely to be local and site-specific, rather than reflecting regional climate changes. A new core sequence from Nar lake has been dated by varve counting and U-Th as covering the last 13,800 years (Dean et al., 2015; Roberts et al., 2016). Periods of marked dryness are associated with peaks in Mg/dolomite, elevated Diatom-Inferred Electrical Conductivity, an absence of laminated sediments, and low Quercus/chenopod ratios. These conditions occurred during the Late-Glacial stadial, at 4.3-3.7 and 3.2-2.6 ka BP. Wet phases occurred during the early Holocene and again 1.5-0.6 ka, characterised by negative δ18O values, calcite precipitation, high Ca/Sr ratios, a high % of planktonic diatoms, laminated sediments, and high Quercus/chenopod ratios. Comparison with the independently dated record from Eski Acıgöl (Roberts et al., 2001) shows good correspondence for many proxies, especially for δ18O. A ranking of multiple proxies shows the worst correspondence is for clastic lithogenic elements (e.g. Ti flux). Differences between the two lake records are caused by basin infilling at Eski Acıgöl, which fails to register climatic changes during the last 2 ka, and to catchment erosion and increased flux of lithogenic elements into Nar lake; this is catchment-specific and primarily anthropogenic rather than climatic in origin. In separating a regional signal from site-specific "noise", two lakes may therefore be better than one. Dean, J.R. et al. 2015 Eastern Mediterranean hydroclimate over the late glacial and Holocene, reconstructed from the sediments of Nar lake, central Turkey, using stable isotopes and carbonate mineralogy. Quaternary

  16. Atmospheric production signal in 10Be from varved sediments of Lake Meerfelder Maar during the late glacial-early Holocene transition

    NASA Astrophysics Data System (ADS)

    Czymzik, Markus; Adolphi, Florian; Muscheler, Raimund; Brauer, Achim; Mekhaldi, Florian; Martin-Puertas, Celia; Tjallingii, Rik; Aldahan, Ala; Possnert, Göran

    2016-04-01

    Beryllium 10 concentrations (10Becon) were measured at 20-year resolution in annually laminated (varved) sediments of Lake Meerfelder Maar (western Germany) covering the late glacial-early Holocene transition 11310-13130 varve years before present. Comparing the 10Becon record to environmental proxy records from the same archive indicates that varying sediment accumulation and composition only slightly modify trends, but do not substantially influence multi-decadal to centennial 10Becon excursions. Corrected for potential environmental biases using multiple-regression analysis, the resulting 10Beatmosphere time-series likely represents an alternative mid-latitude 10Be production record, exhibiting broad similarities but also some differences to radionuclide records as 14C in tree rings and 10Be in polar ice cores. The preservation of the globally common atmospheric production signal in 10Be from varved lake sediments indicates the, to date, largely unexplored potential of these archives for the synchronization to other radionuclide records around the globe, complementing existing solar activity reconstructions and Sun-climate studies.

  17. Rock-magnetic signatures of aeolian activity, precipitation and extreme runoff events from the sediments of Laguna Potrok Aike (southern Patagonia) since 51,200 cal BP

    NASA Astrophysics Data System (ADS)

    St-Onge, G.; Lisé-Pronovost, A.; Gogorza, C. S. G.; Haberzettl, T.; Jouve, G.; Francus, P.; Ohlendorf, C.; Gebhardt, C.; Zolitschka, B.

    2014-12-01

    The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Here we use high-resolution u-channel, as well as discrete rock-magnetic and physical grain size data from the 106 m long core (~51,200 cal BP) of site 2 of the ICDP Potrok Aike maar lake Sediment Archive Drilling project (PASADO) in order to develop magnetic proxies of dust and wind intensity, as well as precipitation and extreme runoff events. Rock-magnetic analyses indicate the magnetic mineral assemblage is dominated by detrital magnetite and that low field magnetic susceptibility (kLF) can be interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale. On shorter time scales however, kLF variability is correlated to ferrimagnetic grain size and coercivity. Comparison to physical grain-size data indicates that the median destructive field of the isothermal remanent magnetisation (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension and that MDFIRM can be interpreted as a wind-intensity proxy, with stronger winds capable of transporting coarser silts to the lake. In addition, about half of the sedimentary sequence is composed of mass movement deposits (MMDs). Within these MMDs, two distinct sedimentary facies can easily be identified. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of a gyroremanent magnetisation (GRM) acquired during demagnetisation of the natural remanent magnetisation (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetisation

  18. Syn- and posteruptive hazards of maar diatreme volcanoes

    NASA Astrophysics Data System (ADS)

    Lorenz, Volker

    2007-01-01

    hazards concern erosion and formation of lahars. Inside the crater a lake usually forms and diverse types of sediments accumulate in the crater. Volcanic gases may be released in the crater. Compaction and other diagenetic processes within the diatreme fill result in its subsidence. This posteruptive subsidence of the diatreme fill and thus crater floor is relatively large initially but will decrease with time. It may last millions of years. Various studies and monitoring are suggested for syn- and posteruptive activities of maar-diatreme volcanoes erupting in the future. The recently formed maar-diatreme volcanoes should be investigated repeatedly to understand more about their syneruptive behaviour and hazards and also their posteruptive topographic, limnic, and biologic evolution, and potential posteruptive hazards. For future maar-diatreme eruptions a hazard map with four principal hazard zones is suggested with the two innermost ones having a joint radius of up to 5 km. Areas that are potentially endangered by maar-diatreme eruptions in the future are pointed out.

  19. Reconstructing paleoenvironment, eruption mechanism and paleomorphology of the Pliocene Pula maar, (Hungary)

    NASA Astrophysics Data System (ADS)

    Németh, K.; Goth, K.; Martin, U.; Csillag, G.; Suhr, P.

    2008-10-01

    of a combination of syn-eruptive subsidence due to mass deficit in the rigid Triassic dolomite basement caused by the phreatomagmatic explosions as well as post-eruptive subsidence of the crater- and diatreme-filling successions due to diagenetic compaction. The facies in the centre of the maar lake is a soft laminated "alginite" (mainly Botryococcus colonies, diatom frustles, calcium carbonate crystals, clay minerals). In the section exposed in the Pula open cast mine, a single turbiditic layer is present. This layer originated in a landslide, which possibly could have been caused by either syn-eruptive earthquake and/or a sudden post-eruptive subsidence event of the diatreme fill.

  20. Hunting remnants of maar-diatreme-volcanoes

    NASA Astrophysics Data System (ADS)

    Kroner, Corinna; Kämpf, Horst; Matthes, Heidrun; Jahr, Thomas; Markwart, David; Hermann, Tobias; Mrlina, Jan

    2010-05-01

    In the area of the Rostock-Leipzig-Regensburg fault zone (Germany) several centres of seismic activity are found with seismicity manifesting itself in swarm earthquakes. The occurrence of these earthquakes is globally linked to ascending magma and magmatic fluids. Information is scarce regarding the depth and geometry of the magmatic source, dynamics in the sub-Moho/lower crust region and fluid-tectonic processes in the upper crust in this area. From studies of maar structures located in the seismic active section of the fault zone magma-tectonic phenomena can be reconstructed. For this purpose two relicts of maar volcanoes of different age within a distance of 60 km are investigated by geophysical surveys. Both structures are located in a distance of a few 10 km from recent swarm earthquake centres. The diatreme structure near Ebersbrunn/W-Saxony which is probably of tertiary age is known for several years, the late Quaternary, volcanic palaeo-lake near Mýtina close to the Czech-German border was only recently discovered. Both structures are characterized by distinct gravimetric and magnetic anomalies of about -2 mGal and several 100 nT resp. indicating steeply dipping structures as well as electrical conductivity anomalies. The magnetic total field anomaly of the Ebersbrunn structure has an uncommon rugged appearance. The hypothesis of an origin related to a redistribution of material with high magnetic susceptibility values and saponification of magnetic minerals due to melt water run-off after the last glacial period could not be confirmed. Thus the heterogeneous anomaly character appears to be mainly associated with the degree of weathering of the volcanic material within the diatreme with depth. From 3D gravimetric and magnetic modelling information is gained on geometry and structural composition. Drilling results were used as additional boundary conditions. In both cases modelling reveals an inner zone of significantly reduced density and increased

  1. Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)

    NASA Astrophysics Data System (ADS)

    Luecke, Andreas; Wissel, Holger; Mayr*, Christoph; Oehlerich, Markus; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

    2010-05-01

    The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok Aike and developed the environmental history of the semi-arid Patagonian steppe by a consequent interdisciplinary multi-proxy approach (e.g. Haberzettl et al., 2007). From September to November 2008 the ICDP deep drilling took place and successfully recovered in total 510 m of sediments from two sites resulting in a composite depth of 106 m for the selected main study Site 2. A preliminary age model places the record within the last 50.000 years. During the drilling campaign, the core catcher content of each drilled core run (3 m) was taken as separate sample to be shared and distributed between involved laboratories long before the main sampling party. A total of 70 core catcher samples describe the sediments of Site 2 and will form the base for more detailed investigations on the palaeoclimatic history of Patagonia. We here report on the organic carbon and nitrogen isotope composition of bulk sediment and plant debris of the core catcher samples. Similar investigations were performed for Holocene and Late Glacial sediments of Laguna Potrok Aike revealing insights into the organic matter dynamics of the lake and its catchment as well as into climatically induced hydrological variations with related lake level fluctuations (Mayr et al., 2009). The carbon and nitrogen content of the core catcher fine sediment fraction (<200 µm) is low to very low (around 1 % and 0.1 %, respectively) and requires particular attention in isotope analysis. The carbon isotope composition shows comparably little variation around a value of -26.0 per mil. The positive values of the Holocene and the Late

  2. The formation and evolution of Hule and Río Cuarto maars, Costa Rica

    NASA Astrophysics Data System (ADS)

    Alvarado, Guillermo E.; Soto, Gerardo J.; Salani, Flavia M.; Ruiz, Pablo; de Mendoza, Luis Hurtado

    2011-04-01

    to be 4.4 × 10 7 m 3, of which 0.008 m 3 correspond to DRE magma. The Hule and Río Cuarto maars are occupied by lakes and, in the last decades, several lake-overturn events have taken place, with a repeat cycle of six to seven years. The main outcome of these events has been the mass death of fish accompanied by changes in the lake color. In these systems, the hazard related to the possible occurrence of Nyos-type gas eruptions can be considered negligible or very local, but significant for tourists who camp by the lakes.

  3. The Randeck Maar: Facies development and habitat differentiation of a Miocene lacustrine system

    NASA Astrophysics Data System (ADS)

    Rasser, Michael W.; Kern, Andrea K.

    2015-04-01

    The Randeck Maar in S Germany is a well-known fossil lagerstätte (Early/Middle Miocene, MN5) with exceptionally preserved fossils. Although it is a locally restricted succession of lake sediments with a diameter of only 1200 m and less than 60 m of preserved sediments, it appears to comprise a complex structure with a high scientific potential on a global scale, because the lake sediments and their fossils can provide evidence for the impact of the Mid-Miocene Climatic Optimum (MMCO) on the environment and its organisms as well as the ecological interactions between animals and/or plants during that interval. No other European locality provides such a rich insight into an ecosystem that existed during the MMCO. Excavations of Staatliches Museum für Naturkunde Stuttgart provided new insights into the facies types of this maar lake. They showed that a high variety of facies types existed beside the traditional separation into a basal tuffitic development, followed by calcareous and bituminous ('dysodil') laminates, and terminal massive freshwater limestones. Palaeoenvironmental reconstructions are based on the mentioned excavations and re-evaluations of collection material. They show that the Randeck Maar was a typical maar lake with a rich flora and fauna. Based on all plant remains, the IPR vegetational analysis points towards subhumid sclerophyllous forests, suggesting seasonal drought. 380 taxa in all are known thus far, which are dominated by plants (168) and insects (79). The taxonomic re-evaluation combined with palaeoecological considerations allows for the reconstruction of a palaeoenvironmental model. In brief, three main sections can be differentiated for the habitats of the Randeck Maar lake system: (1) Deep- and open-water lake habitats with local and short-termed mass occurrences of insect larvae, amphibians, and/or gastropods, while fish are particularly scarce. The interpretation of the water chemistry is problematic because palaeoenvironmental

  4. High-resolution paleomagnetic records from Laguna Potrok Aike (Patagonia, Argentina) for the last 16,000 years

    NASA Astrophysics Data System (ADS)

    Gogorza, Claudia S. G.; Irurzun, MaríA. A.; Sinito, Ana M.; Lisé-Pronovost, Agathe; St-Onge, Guillaume; Haberzettl, Torsten; Ohlendorf, Christian; Kastner, Stephanie; Zolitschka, Bernd

    2012-02-01

    Holocene and Late-glacial records documenting variations in direction and intensity of the geomagnetic field during the last 16,000 cal. BP are presented for Southern Patagonia. This continuous high-resolution terrestrial record from Laguna Potrok Aike (51°58'S, 70°23'W) was recovered within the SALSA (South Argentinean Lake Sediment Archives and modeling) project. Mineral magnetic measurements indicate that pseudo single-domain magnetite is the major carrier of the remanence allowing the reliable determination of stable natural remanent magnetization inclinations and declinations from alternating field demagnetization and principal component analysis. Paleomagnetic secular variation records reveal most of the familiar features of declination and inclination that have previously been reported in other records from South Argentina but conspicuous centennial-scale differences are also observed. The results illustrate the potential of paleosecular variations records for dating sedimentary sequences in southern South America.

  5. OSL dating of a Pleistocene maar: Birket Ram, the Golan heights

    USGS Publications Warehouse

    Shaanan, U.; Porat, N.; Navon, O.; Weinberger, R.; Calvert, A.; Weinstein, Y.

    2011-01-01

    Direct dating of maars and their phreatomagmatic deposits is difficult due to the dominance of lithic (host rock) fragments and glassy particles of the juvenile magma. In this paper we demonstrate that optically stimulated luminescence (OSL) dating can be successfully used for age determination of phreatomagmatic deposits. We studied the tuff deposit of Birket Ram, a basanitic maar located at the northern edge of the Golan heights on the western Arabian plate. The maar is underlain by a thick section of Pleistocene basalts, and currently hosts a small lake. It is filled by approximately 90m of lacustrine sediments with radiocarbon ages extrapolated to 108ka at the base. OSL was applied to quartz grains extracted from tuffs and paleosols in order to set the time frame of the phreatomagmatism at the site. A maximum age constraint of 179??13ka was determined for a paleosol that underlies the maar ejecta. Quartz grains from two layers in the tuff section yielded a direct age of 129??6ka for the phreatomagmatic eruption. A younger age of 104??7ka, which was determined for a tuff layer underlying a basaltic flow, was attributed to thermal resetting during the lava emplacement. This was confirmed by an 40Ar/39Ar age of 101??3ka determined on the overlying basalt. The internal consistency of the OSL ages and the agreement with the 40Ar/39Ar age determination as well as with previous estimates demonstrates the potential of OSL for maar dating. ?? 2010 Elsevier B.V.

  6. Reconstructing paleoenvironmental conditions during the past 50 ka from the biogeochemical record of Laguna Potrok Aike, southern Patagonia

    NASA Astrophysics Data System (ADS)

    Hahn, A.; Rosén, P.; Kliem, P.; Ohlendorf, C.; Zolitschka, B.

    2011-12-01

    Total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) assessed by Fourier transform infrared spectroscopy (FTIRS) are used to reconstruct the environmental history during the past 50kyrs in high resolution from Laguna Potrok Aike. During the Holocene warmer conditions lead to an increased productivity reflected in higher TOC and BSi contents. Calcite precipitation initiated around 9 ka cal. BP probably due to supersaturation induced by lake level lowering. It is assumed that prior to this time period sediments are carbonate-free because high lake-level conditions prevailed. During the Glacial, increased runoff linked to permafrost, precipitation related to stronger cyclonic activity and reduced evaporation have caused higher lake levels. Moreover, during cold glacial conditions lake productivity was low and organic matter mainly of algal or cyanobacterial origin as indicated by generally low TOC and C/N values. During interstadials, such as the Antarctic A-events and the Younger Dryas, TOC contents appear to rise. The glacial C/N ratios and their correlation with TOC concentrations indicate that aquatic moss blooms probably induce these increases in TOC. Aquatic mosses grow if surface water temperatures rise due to warmer climatic conditions and/or development of a lake water stratification. The latter may occur if wind speeds are low and melt water inflow caused higher density gradients. Prevailing permafrost thawing during warmer periods could lead to considerable rises of lake levels, which would contribute to the preservation of organic material. This may explain why higher C/N and TOC values occur at the end of Antarctic A-events. For the uppermost 25 m, the BSi profile shows a high correlation with the TOC profile. In deeper horizons, however, there are indications that the BSi/TOC ratio increased. This part of the record is dominated by mass movement events, which may have supplied nutrients and thus triggered diatom blooms.

  7. The Maars of the Tuxtla Volcanic Field: the Example of 'laguna Pizatal'

    NASA Astrophysics Data System (ADS)

    Espindola, J.; Zamora-Camacho, A.; Hernandez-Cardona, A.; Alvarez del Castillo, E.; Godinez, M.

    2013-12-01

    Los Tuxtlas Volcanic Field (TVF), also known as Los Tuxtlas massif, is a structure of volcanic rocks rising conspicuously in the south-central part of the coastal plains of eastern Mexico. The TVF seems related to the upper cretaceous magmatism of the NW part of the Gulf's margin (e.g. San Carlos and Sierra de Tamaulipas alkaline complexes) rather than to the nearby Mexican Volcanic Belt. The volcanism in this field began in late Miocene and has continued in historical times, The TVF is composed of 4 large volcanoes (San Martin Tuxtla, San Martin Pajapan, Santa Marta, Cerro El Vigia), at least 365 volcanic cones and 43 maars. In this poster we present the distribution of the maars, their size and depths. These maars span from a few hundred km to almost 1 km in average diameter, and a few meters to several tens of meters in depth; most of them filled with lakes. As an example on the nature of these structures we present our results of the ongoing study of 'Laguna Pizatal or Pisatal' (18° 33'N, 95° 16.4'W, 428 masl) located some 3 km from the village of Reforma, on the western side of San Martin Tuxtla volcano. Laguna Pisatal is a maar some 500 meters in radius and a depth about 40 meters from the surrounding ground level. It is covered by a lake 200 m2 in extent fed by a spring discharging on its western side. We examined a succession of 15 layers on the margins of the maar, these layers are blast deposits of different sizes interbedded by surge deposits. Most of the contacts between layers are irregular; which suggests scouring during deposition of the upper beds. This in turn suggests that the layers were deposited in a rapid series of explosions, which mixed juvenile material with fragments of the preexisting bedrock. We were unable to find the extent of these deposits since the surrounding areas are nowadays sugar cane plantations and the lake has overspilled in several occassions.

  8. Tephra ring interpretation in light of evolving maar-diatreme concepts: Stracciacappa maar (central Italy)

    NASA Astrophysics Data System (ADS)

    Valentine, G. A.; Sottili, G.; Palladino, D. M.; Taddeucci, J.

    2015-12-01

    Maar-diatreme volcanoes in their simplest form are thought to result primarily from discrete, subsurface phreatomagmatic explosions. Tephra ring deposits around maar craters are commonly interpreted in terms of a framework wherein explosions begin at shallow levels and migrate downward, ejecting progressively deeper-seated lithic clasts that contribute to the tephra rings. Additionally, variations in grain size of the deposits are sometimes inferred to record different degrees of fragmentation, which are in turn related to variations in magma-water ratios at the explosion sites. Recent detailed studies of diatremes and of maar tephra rings suggest a different conceptual model wherein explosions can happen at various vertical and lateral locations within a diatreme during its eruptive lifetime, rather than being limited to simple downward migration. Experiments, numerical modeling, and field data indicate that most explosions deeper than about 200-250 m will not vent to the surface, but instead contribute to mixing within the diatremes. Arrival of deep-seated lithics at the surface is related to this mixing process. Experiments also indicate that explosion phenomena can result in a range of emplacement mechanisms and grain sizes in tephra rings, even in the absence of variations in explosion mechanisms (fragmentation efficiency). Here we document the tephra ring of Stracciacappa maar (central Italy), and interpret its eruption and emplacement history in terms of evolving conceptual models along with a comparison to more traditional interpretations. The Stracciacappa deposits include a range of depositional facies and grain sizes that could be related to different combinations of explosion energy, depth, and crater geometry. Lithic abundances are quite variable, including within individual beds, and are consistent with eruption of debris jet deposits from a diatreme beneath the maar. Because most elements of both conceptual models are viable, the work points to an

  9. Linking microbial assemblages to paleoenvironmental conditions from the Holocene and Last Glacial Maximum times in Laguna Potrok Aike sediments, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, Aurele; Ariztegui, Daniel; Leavitt, Peter R.; Bunting, Lynda

    2014-05-01

    Laguna Potrok Aike is a closed basin located in the southern hemisphere's mid-latitudes (52°S) where paleoenvironmental conditions were recorded as temporal sedimentary sequences resulting from variations in the regional hydrological regime and geology of the catchment. The interpretation of the limnogeological multiproxy record developed during the ICDP-PASADO project allowed the identification of contrasting time windows associated with the fluctuations of Southern Westerly Winds. In the framework of this project, a 100-m-long core was also dedicated to a detailed geomicrobiological study which aimed at a thorough investigation of the lacustrine subsurface biosphere. Indeed, aquatic sediments do not only record past climatic conditions, but also provide a wide range of ecological niches for microbes. In this context, the influence of environmental features upon microbial development and survival remained still unexplored for the deep lacustrine realm. Therefore, we investigated living microbes throughout the sedimentary sequence using in situ ATP assays and DAPI cell count. These results, compiled with pore water analysis, SEM microscopy of authigenic concretions and methane and fatty acid biogeochemistry, provided evidence for a sustained microbial activity in deep sediments and pinpointed the substantial role of microbial processes in modifying initial organic and mineral fractions. Finally, because the genetic material associated with microorganisms can be preserved in sediments over millennia, we extracted environmental DNA from Laguna Potrok Aike sediments and established 16S rRNA bacterial and archaeal clone libraries to better define the use of DNA-based techniques in reconstructing past environments. We focused on two sedimentary horizons both displaying in situ microbial activity, respectively corresponding to the Holocene and Last Glacial Maximum periods. Sequences recovered from the productive Holocene record revealed a microbial community adapted to

  10. Felsic maar-diatreme volcanoes: a review

    NASA Astrophysics Data System (ADS)

    Ross, Pierre-Simon; Carrasco Núñez, Gerardo; Hayman, Patrick

    2017-02-01

    Felsic maar-diatreme volcanoes host major ore deposits but have been largely ignored in the volcanology literature, especially for the diatreme portion of the system. Here, we use two Mexican tuff rings as analogs for the maar ejecta ring, new observations from one diatreme, and the economic geology literature on four other mineralized felsic maar-diatremes to produce an integrated picture of this type of volcano. The ejecta rings are up to 50 m+ thick and extend laterally up to ˜1.5 km from the crater edge. In two Mexican examples, the lower part of the ejecta ring is dominated by pyroclastic surge deposits with abundant lithic clasts (up to 80% at Hoya de Estrada). These deposits display low-angle cross-bedding, dune bedforms, undulating beds, channels, bomb sags, and accretionary lapilli and are interpreted as phreatomagmatic. Rhyolitic juvenile clasts at Tepexitl have only 0-25% vesicles in this portion of the ring. The upper parts of the ejecta ring sequences in the Mexican examples have a different character: lithic clasts can be less abundant, the grain size is typically coarser, and the juvenile clasts can be different in character (with some more vesicular fragments). Fragmentation was probably shallower at this stage. The post-eruptive maar crater infill is known at Wau and consists of reworked pyroclastic deposits as well as lacustrine and other sediments. Underneath are bedded upper diatreme deposits, interpreted as pyroclastic surge and fall deposits. The upper diatreme and post-eruptive crater deposits have dips larger than 30° at Wau, with approximately centroclinal attitudes. At still lower structural levels, the diatreme pyroclastic infill is largely unbedded; Montana Tunnels and Kelian are good examples of this. At Cerro de Pasco, the pyroclastic infill seems bedded despite about 500 m of post-eruptive erosion relative to the pre-eruptive surface. The contact between the country rocks and the diatreme is sometimes characterized by country rock

  11. AIK1, A Mitogen-Activated Protein Kinase, Modulates Abscisic Acid Responses through the MKK5-MPK6 Kinase Cascade1[OPEN

    PubMed Central

    Li, Kun; Yang, Fengbo; Zhang, Guozeng; Song, Shufei; Li, Yuan; Ren, Dongtao; Miao, Yuchen

    2017-01-01

    The mitogen-activated protein kinase (MAPK) cascade is an evolutionarily conserved signal transduction module involved in transducing extracellular signals to the nucleus for appropriate cellular adjustment. This cascade essentially consists of three components: a MAPK kinase kinase (MAPKKK), a MAPK kinase, and a MAPK, connected to each other by the event of phosphorylation. Here, we report the characterization of a MAPKKK, ABA-INSENSITIVE PROTEIN KINASE1 (AIK1), which regulates abscisic acid (ABA) responses in Arabidopsis (Arabidopsis thaliana). T-DNA insertion mutants of AIK1 showed insensitivity to ABA in terms of both root growth and stomatal response. AIK1 functions in ABA responses via regulation of root cell division and elongation, as well as stomatal responses. The activity of AIK1 is induced by ABA in Arabidopsis and tobacco (Nicotiana benthamiana), and the Arabidopsis protein phosphatase type 2C, ABI1, a negative regulator of ABA signaling, restricts AIK1 activity by dephosphorylation. Bimolecular fluorescence complementation analysis showed that MPK3, MPK6, and AIK1 interact with MKK5. The single mutant seedlings of mpk6 and mkk5 have similar phenotypes to aik1, but mkk4 does not. AIK1 was localized in the cytoplasm and shown to activate MKK5 by protein phosphorylation, which was an ABA-activated process. Constitutively active MKK5 in aik1 mutant seedlings complements the ABA-insensitive root growth phenotype of aik1. The activity of MPK6 was increased by ABA in wild-type seedlings, but its activation by ABA was impaired in aik1 and aik1 mkk5 mutants. These findings clearly suggest that the AIK1-MKK5-MPK6 cascade functions in the ABA regulation of primary root growth and stomatal response. PMID:27913741

  12. Climate induced changes as registered in inorganic and organic sediment components from Laguna Potrok Aike (Argentina) during the past 51 ka

    NASA Astrophysics Data System (ADS)

    Hahn, A.; Kliem, P.; Ohlendorf, C.; Zolitschka, B.; Rosén, P.; Pasado Science Team

    2013-07-01

    Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51 ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHW) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during

  13. Qal'eh Hasan Ali maars, central Iran.

    USGS Publications Warehouse

    Milton, D.J.

    1976-01-01

    This group of some 15 Late Quaternary explosion craters are typical maars, with rims of bedded pyroclastics. In all but the largest crater, the deposits consist entirely of clasts of country rock (granodiorite and Eocene volcanics). The maars were formed by phreatomagmatic explosions, possibly caused by groundwater originating from a major river. The deposits of the largest maar contain up to 20% juvenile fragments of two types. Tephrite clasts have phenocrysts of phlogopite, clinopyroxene, olivine and anorthoclase; the presence of hauyne as a groundmass phase is notable. Cumulate blocks of phlogopite-clinopyroxene rock also occur. The maar field is part of a distinct province of Quaternary alkaline volcanism, related to a major crustal fracture - the N-S-trending Nayband fault.-R.J.S.

  14. Magnetic parameters and their palaeoclimatic implications—the sediment record of the last 15 500 cal. BP from Laguna Potrok Aike (Argentina)

    NASA Astrophysics Data System (ADS)

    Irurzun, M. A.; Orgeira, M. J.; Gogorza, C. S. G.; Sinito, A. M.; Compagnucci, R.; Zolitschka, B.

    2014-08-01

    Lake sediments are excellent sources of palaeoenvironmental and palaeoclimatic information because they provide continuous and high-resolution records. South America is of particular interest because it is the only landmass that stretches southward into the Pacific and Atlantic Oceans towards Antarctica. The aim of this study is to explore the relationship of magnetic parameters with elemental and palaeobiological data of Laguna Potrok Aike to develop a model of lake-level changes and related hydrological and climatic fluctuations. Magnetic measurements were performed on subsamples from 15 500 cal. BP to the present, and associated rock magnetic parameters were calculated to infer magnetic mineralogy, concentration and grain size. According to the model, parameters dependent on magnetic concentration and grain size are directly related to lake-level changes. During dry periods, the remanent coercivity displays high values, whereas the proportion of magnetite is relatively low. Low percentages of greigite are observed, indicating that the water of the lake was stratified at least four times during the studied period, at approximately 10 300, 8900, 8500 and 8300 cal. BP. The preservation of greigite by inhibiting its complete transformation into pyrite is associated with a rapid burial that occurs with high sedimentation rates. Thermal stratification could be caused by a slight cooling in the area triggered by a weakening of the Westerlies and/or low activity of the sun, sum to the effect of a flood of melt water in the North Atlantic.

  15. Recording of climate and diagenesis through fossil pigments and sedimentary DNA at Laguna Potrok Aike, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, A.; Ariztegui, D.; Leavitt, P. R.; Bunting, L.; Pasado Science Team

    2015-11-01

    Aquatic sediments record past climatic conditions while providing a wide range of ecological niches for microorganisms. Although marine sedimentary microbial assemblages are often defined by their surrounding geochemical conditions, the influence of environmental features upon microbial development and post-depositional survival remains largely unknown in the lacustrine realm. Due to long-term microbial activity, the composition of environmental DNA can be expected to evolve with sediment depth and over time and therefore should reflect both ancient and extant microbial populations, but this hypothesis has rarely been tested using a multiproxy approach. Here geomicrobiological and phylogenetic analyses of a Patagonian maar lake were used to indicate that the different sedimentary microbial assemblages derive from specific lacustrine regimes during defined climatic periods. Two well defined climatic intervals whose sediments harboured active microbial populations and measurable ATP were sampled for a comparative environmental study based on fossil pigments and 16S rRNA gene sequences. Bacterial and archaeal 16S rRNA gene sequences recovered from the Holocene record revealed a microbial community adapted to subsaline conditions actively producing methane during organic matter degradation. These characteristics were associated with sediments resulting from endorheic lake conditions with high evaporative stress and concomitant high algal productivity. Moreover, archaeal clone libraries established throughout the Holocene record indicate an age-related stratification of these populations, consistent with a gradual use of organic substrates after deposition. In contrast, sulphate-reducing bacteria and lithotrophic Archaea were predominant in sediments dated from the Last Glacial Maximum, in which pelagic clays alternated with fine volcanic material characteristic of a lake level highstand and freshwater conditions, but reduced water column productivity. These patterns

  16. Recording of climate and diagenesis through sedimentary DNA and fossil pigments at Laguna Potrok Aike, Argentina

    NASA Astrophysics Data System (ADS)

    Vuillemin, Aurèle; Ariztegui, Daniel; Leavitt, Peter R.; Bunting, Lynda; The Pasado Science Team

    2016-04-01

    Aquatic sediments record past climatic conditions while providing a wide range of ecological niches for microorganisms. In theory, benthic microbial community composition should depend on environmental features and geochemical conditions of surrounding sediments, as well as ontogeny of the subsurface environment as sediment degraded. In principle, DNA in sediments should be composed of ancient and extant microbial elements persisting at different degrees of preservation, although to date few studies have quantified the relative influence of each factor in regulating final composition of total sedimentary DNA assemblage. Here geomicrobiological and phylogenetic analyses of a Patagonian maar lake were used to indicate that the different sedimentary microbial assemblages derive from specific lacustrine regimes during defined climatic periods. Two climatic intervals (Mid-Holocene, 5 ka BP; Last Glacial Maximum, 25 ka BP) whose sediments harbored active microbial populations were sampled for a comparative environmental study based on fossil pigments and 16S rRNA gene sequences. The genetic assemblage recovered from the Holocene record revealed a microbial community displaying metabolic complementarities that allowed prolonged degradation of organic matter to methane. The series of Archaea identified throughout the Holocene record indicated an age-related stratification of these populations brought on by environmental selection during early diagenesis. These characteristics were associated with sediments resulting from endorheic lake conditions and stable pelagic regime, high evaporative stress and concomitant high algal productivity. In contrast, sulphate-reducing bacteria and lithotrophic Archaea were predominant in sediments dated from the Last Glacial Maximum, in which pelagic clays alternated with fine volcanic material characteristic of a lake level highstand and freshwater conditions, but reduced water column productivity. Comparison of sedimentary DNA composition

  17. A Flood Layer Reconstruction from the Laminated Sediments of Eifel Maar Structures (Germany) during the Last 60 000 Years

    NASA Astrophysics Data System (ADS)

    Brunck, H.; Sirocko, F.

    2015-12-01

    Lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. This study reconstructs the history of the main flood events in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. The cores were drilled in the Eifel region of western Germany. All maars have an inflow by a local stream and the largest flood events and associated suspension injections are nicely visible in the sediment. The specific sedimentation conditions explain the unique possibility to detect all 18 Greenland Interstadials in the total carbon concentration of the analysed maars. The allocation of the core material to all Greenland Interstadials and Stadials enables the exact climatic interpretation of the flood frequency. The stratigraphical concept leads to a classification of Landscape Evolution Zones in the Eifel region, which reconstruct the vegetation and the climate change. This classification is used to discuss the flood event succession concerning environmental changes. To study the past flood events in detail, 10 cm long thin sections were sedimentological and geochemical analysed to distinguish flood layers from turbidites and slumps.Turbidites have a continuous grain size gradation; the grain size profile of flood events is in contrast characterized by several grain size maxima over the entire layer thickness. A flood event over several days shows numerous peaks of intense discharge, which lead to a discontinuous grain size gradient. As a consequence, 233 flood layers over 7.5 mm thickness were detected. The main flood stages are from: 0 - 4000, 11 500 - 17 500, 23 000 - 24 000, 29 000 - 35 000 and 44 000 - 44 500 b2k. Our time-series from the Eifel represents the first highly-resolved chronology for flood events from 60 000 years until present times and

  18. 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…

  19. Characterizing the eolian sediment component in the lacustrine record of Laguna Potrok Aike (southeastern Patagonia)

    NASA Astrophysics Data System (ADS)

    Ohlendorf, C.; Gebhardt, C.

    2013-12-01

    Southern South America with its extended dry areas was one of the major sources for dust in the higher latitudes of the southern hemisphere during the last Glacial, as was deduced from fingerprinting of dust particles found in Antarctic ice cores. The amount of dust that was mobilized is mostly related to strength and latitudinal position of the Southern Hemisphere Westerly Winds (SWW). How exactly SWW shifted between glacial and interglacial times and what consequences such shifts had for ocean and atmospheric circulation changes during the last deglaciation is currently under debate. Laguna Potrok Aike (PTA) as a lake situated in the middle of the source area of dust offers the opportunity to arrive at a better understanding of past SWW changes and their associated consequences for dust transport. For this task, a sediment record of the past ~51 ka is available from a deep drilling campaign (PASADO). From this 106 m long profile, 76 samples representing the different lithologies of the sediment sequence were selected to characterize an eolian sediment component. Prior to sampling of the respective core intervals, magnetic susceptibility was measured and the element composition was determined by XRF-scanning on fresh, undisturbed sediment. After sampling and freeze drying, physical, chemical and mineralogical sediment properties were determined before and after separation of each sample into six grainsize classes for each fraction separately. SEM techniques were used to verify the eolian origin of grains. The aim of this approach is to isolate an exploitable fingerprint of the eolian sediment component in terms of their grain size, physical properties, geochemistry and mineralogy. Thereby, the challenging aspect is that such a fingerprint should be based on high-resolution down-core scanning techniques, so time-consuming techniques such as grain-size measurements by laser detection can be avoided. A first evaluation of the dataset indicates that magnetic

  20. The ELSA - Flood - Stack: A reconstruction from the laminated sediments of Eifel Maar structures during the last 60 000 years

    NASA Astrophysics Data System (ADS)

    Brunck, Heiko; Sirocko, Frank; Albert, Johannes

    2016-04-01

    Lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. This study reconstructs the history of the main flood events in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. The cores were drilled in the Eifel region of western Germany. All maars have an inflow by a local stream and the largest flood events and associated suspension injections are nicely visible in the sediment. The specific sedimentation conditions explain the unique possibility to detect all 18 Greenland Interstadials in the total carbon concentration of the analysed maars. The allocation of the core material to all Greenland Interstadials and Stadials enables the exact climatic interpretation of the flood frequency. The stratigraphical concept leads to a classification of Landscape Evolution Zones in the Eifel region, which reconstruct the vegetation and the climate change (Sirocko et al., 2015). This classification is used to discuss the flood event succession concerning environmental changes. To study the past flood events in detail, 10 cm long thin sections were sedimentological and geochemical analysed to distinguish flood layers from turbidites and slumps. Turbidites have a continuous grain size gradation; the grains size profile of flood events is in contrast characterized by several grain size maxima over the entire layer thickness. A flood event over several days shows numerous peaks of intense discharge, which lead to a discontinuous grain size gradient. As a consequence, 233 flood layers over 7.5 mm thickness were detected. The main flood stages are from: 0 - 4000, 11 500 - 17 500, 23 000 - 24 000, 29 000 - 35 000 and 44 000 - 44 500 b2k (Brunck et al., 2015). Our time-series from the Eifel represents the first highly-resolved chronology for flood

  1. Characterization of polyhydroxyalkanoates (PHAs) biosynthesis by isolated Novosphingobium sp. THA_AIK7 using crude glycerol.

    PubMed

    Teeka, Jantima; Imai, Tsuyoshi; Reungsang, Alissara; Cheng, Xuehang; Yuliani, Emma; Thiantanankul, Jiruthakorn; Poomipuk, Nathaporn; Yamaguchi, Junki; Jeenanong, Anan; Higuchi, Takaya; Yamamoto, Koichi; Sekine, Masahiko

    2012-05-01

    Biodiesel-contaminated wastewater was used to screen for PHAs-producing bacteria by using crude glycerol as the sole carbon source. A gram-negative THA_AIK7 isolate was chosen as a potential PHAs producer. The 16S rRNA phylogeny indicated that THA_AIK7 isolate is a member of Novosphingobium genus which is supported by a bootstrap percentage of 100% with Novosphingobium capsulatum. The 1,487 bp of 16S rRNA gene sequence of THA_AIK7 isolate has been deposited in the GenBank database under the accession number HM031593. Polymer content of 45% cell dry weight was achieved in 72 h with maximum product yield coefficient of 0.29 g PHAs g⁻¹ glycerol. Transmission electron micrograph results exhibited the PHAs granules accumulated inside the bacterial cell. PHAs polymer production in mineral salt media supplemented with 2% (w/v) of crude glycerol at initial pH 7 was extracted by the sodium hypochlorite method. Polymer film spectrographs from Nuclear magnetic resonance displayed a pattern of signal virtually identical to spectra of commercial PHB. Thermal analysis by Differential scanning calorimeter showed a melting temperature at 179°C. Molecular weight analysis by Gel permeation chromatography showed two main peaks of 133,000 and 700 g mol⁻¹ with weight-average molecular weight value of 23,800 and number-average molecular weight value of 755. Endotoxinfree of PHAs polymer was preliminarily assessed by a negative result of the gel-clot formation, Pyrotell® Single test vial, at sensitivity of 0.25 EU ml⁻¹. To our knowledge, this is the first reported test of endotoxin-free PHAs naturally produced from gram-negative bacteria which could be used for biomedical application.

  2. Evidence of post-eruptive subsidence in the Rincón de Parangueo maar, México

    NASA Astrophysics Data System (ADS)

    Aranda-Gomez, J. J.

    2013-05-01

    Subsidence is almost invariably invoked in the formation models of maar-diatreme systems (MDS); it may occur in all MDS as a syn-eruptive and post-eruptive phenomena (Lorenz, Bull Volcanol 48). Post-eruptive subsidence begins immediately after the end of the eruption and compaction may follow an exponential decrease rate during several tens of millions of years (Suhr et al, Z. dt. Ges. Geowiss. 157/3). Post-eruptive subsidence is attributed to diatreme compaction (Pirrung et al, Sedimentology 55); therefore it must occur in all MDS. Field evidence of post-eruptive subsidence in Quaternary maars is uncommon, a fact that suggests that either post-eruptive subsidence does not occur in all the MDS, or most post-eruptive subsidence develops early in the history of MDS and its structural and sedimentological evidences lie buried under younger deposits in the maar craters. Rincón de Parangueo is a Quaternary (~100 ka?) maar desiccated in the 1980s. Today the lake bottom is exposed; near the shore of the former lake are a large number of structures, which are interpreted as evidence of active subsidence of the crater's bottom. The most conspicuous set of structures are located close to a ring-like topographic scarp up to 15 m high. Along the scarp is exposed a segmented ring fault which affects a calcareous platform formed by stromatolites. In most places the ring fault is an array of step-faults with the downthrown blocks toward the depocenter. These extensional structures are unusual as their displacement is ~1:1 combination of movement perpendicular to the fractures and dip-slip normal displacement. The structural attitude of the laminated mud in the scarp suggests that down-sagging is occurring as the result of piston-like subsidence of the bottom of the crater and down slope movement of cohesive blocks towards the depocenter. A structural map shows open folds and in some places domes caused by upward injection of mud in the area between the topographic scarp and the

  3. The ELSA-Flood-Stack: A reconstruction from the laminated sediments of Eifel maar structures during the last 60 000 years

    NASA Astrophysics Data System (ADS)

    Brunck, H.; Sirocko, F.; Albert, J.

    2016-07-01

    This study reconstructs the main flood phases in central Europe from event layers in sediment cores from Holocene Eifel maar lakes and Pleistocene dry maar structures. These reconstructions are combined with recent gauge time-series to cover the entire precipitation extremes of the last 60 000 years. In general, Eifel maar sediments are perfectly suited for the preservation of event layers since the deep water in the maar lakes is seasonal anoxic and therefore, bioturbation is low. However, the preservation of annual lamination is only preserved in Holzmaar and Ulmener Maar; the other cores are dated by 14C, magnetostratigraphy, tephra markers and ice core tuning. The cores were drilled in the Eifel region of central western Germany, which represents a climatic homogenous region from Belgium to Poland and all across Central Europe. A total of 233 flood layers over 7.5 mm were detected in all analysed cores. The stratigraphic classification of the flood events follows the newly defined Landscape Evolution Zones (LEZ). The strongest events in the Holocene have occurred during LEZ 1 (0-6000 b2k) in the years 658, 2800 and 4100 b2k. Flood layers in the LEZ 2 (6000-10 500 b2k) are not as frequent as during the LEZ 1, nevertheless, the floods cluster between 6000 and 6500 b2k. Twenty flood layers are found in the LEZ 3 (10 500-14 700 b2k); 11 in LEZ 4 (14 700-21 000 b2k); 15 in LEZ 5 (21 000-28 500 b2k); 34 in LEZ 6 (28 500-36 500 b2k); 8 in LEZ 7 (36 500-49 000 b2k); zero in LEZ 8 (49 000-55 000 b2k) and LEZ 9 (55 000-60 000 b2k). The maximum flood phases during the Pleistocene are at 11 500-17 500 (late glacial and Younger Dryas), 23 000-24 000 (before Greenland Interstadial (GI) 2), 29 000-35 000 (especially between GI 5 and 4) and 44 000-44 500 b2k (transition from GI 12 to 11). The variations in flood dynamics are climatically driven and mainly associated with climate transitions and colder periods, combined with light vegetation. It turns out that low vegetation

  4. Alberca De Guadalupe Maar Crater, Zacapu Basin : A Rare Type of Volcano within the Michoacán-Guanajuato Volcanic Field, México

    NASA Astrophysics Data System (ADS)

    Kshirsagar, P. V.; Siebe, C.; Guilbaud, M. N.; Salinas, S.

    2014-12-01

    Phreato-magmatic vents (esp. maar craters) are rare in the ~40,000 Km2 Plio-Quaternary monogenetic Michoacán-Guanajuato Volcanic Field (MGVF) located in the central part of the Mexican Volcanic Belt. In contrast to >1000 scoria cones, only 2 dozen phreato-magmatic monogenetic vents (e.g. tuff cones, tuff rings, and maars) have been identified. About half of these form a cluster near Valle de Santiago in the Lerma river valley at the northern margin of the MGVF, while the others occur in a rather scattered fashion. Here we discuss the origin of Alberca de Guadalupe maar crater, one of the three phreato-magmatic vents (in addition to El Caracol and Alberca de Los Espinos) that occur within the boundaries of the inter-montane lacustrine Zacapu basin, a tectonic graben bound by an ENE-WSW normal fault system. The maar crater came into existence between 20,000 and 23,000 y BP, forming a 140 m deep hole in the otherwise planar surrounding ground of theearly Pleistocene lava flows of Cerro Pelón.The maar crater has a diameter of ~1 Km and bears a 9 m deep lake. Eruptive products include typical surge deposits that are best exposed around the rim and inner crater walls. They are poorly sorted (Mdø= -1.56 to -3.75, ø= 1.43 to 3.23), rich in accidental lithics (angular andesitic lava and ignimbrite clasts) constituting 51-88% of the deposit with few juveniles (basaltic andesite with phenocrysts of plagioclase, olivine, and pyroxene in a quenched glassy matrix; SiO2=54-58 wt. %). Dry surge units are friable and clast-supported, in contrast the wet surge units are fairly indurated and bear accretionary lapilli. Bedding is frequently distorted by ballistic impact-sag structures. The entire construct is disrupted by an E-W trending regional fault, downthrowing the northern part by ~30 m.The unusual formation of this maar crater in the semi-arid highlands of Zacapu was favored by the local hydrological and topographical conditions. Such conditions still prevail in several

  5. Late Pleistocene Alberca de Guadalupe maar volcano (Zacapu basin, Michoacán): Stratigraphy, tectonic setting, and paleo-hydrogeological environment

    NASA Astrophysics Data System (ADS)

    Kshirsagar, Pooja; Siebe, Claus; Guilbaud, Marie Noëlle; Salinas, Sergio; Layer, Paul W.

    2015-10-01

    The Late Pleistocene (~ 21,000 yr BP) Alberca de Guadalupe maar is one of the few phreatomagmatic volcanoes occurring within the scoria-cone dominated Plio-Quaternary Michoacán-Guanajuato Volcanic Field. The scarcity of this type of volcano implies that conditions favoring their formation are rarely met in this region. We identify these factors by implementing current methods of investigation with emphasis on hydrogeological conditions. We present the stratigraphy (including a set of 40Ar/39Ar and 14C dates) of the SE margin of the Zacapu intermontane tectonic basin, where the maar just forms a hole (~ 1 km in diameter, ~ 150 m deep, bearing a ~ 9 m deep lake) in the otherwise planar topography of the underlying early Pleistocene lava flows of the Cerro Pelón scoria cone. The maar is composed of typical phreatomagmatic surge deposits that are poorly sorted and rich in accidental lithics (> 60 wt.% of the deposit) with few juveniles (basaltic andesite, SiO2 = 54-58 wt.%). The entire structure is cut by an ENE-WSW trending normal fault and is underlain by andesite lavas and silicic ignimbrites (partly inferred from xenoliths encountered in the maar deposits) that are Miocene to Early Pleistocene in age. The crater is at the center of a N-S elongated drainage basin surrounded by topographic highlands that channel water with high hydraulic pressure from most directions towards the location of the maar. This geometric configuration was already in existence at the time of the maar-forming eruption, but the climate was different. Colder and more humid conditions during the Last Glacial Maximum (Cw2-climate type, annual precipitation of > 1000 mm) favored the saturation of the fractured shallow aquifer system (hydraulic conductivity of 10- 8 to 10- 7 m/s) that supplied sufficient groundwater at a high flow rate directed towards the center of the basin. Upon contact near surface (< 200 m) with the rising dike of basaltic andesite magma, the continuous supply of both dike

  6. Recombinant Measles AIK-C Vaccine Strain Expressing the prM-E Antigen of Japanese Encephalitis Virus.

    PubMed

    Higuchi, Akira; Toriniwa, Hiroko; Komiya, Tomoyoshi; Nakayama, Tetsuo

    2016-01-01

    An inactivated Japanese encephalitis virus (JEV) vaccine, which induces neutralizing antibodies, has been used for many years in Japan. In the present study, the JEV prM-E protein gene was cloned, inserted at the P/M junction of measles AIK-C cDNA, and an infectious virus was recovered. The JEV E protein was expressed in B95a cells infected with the recombinant virus. Cotton rats were inoculated with recombinant virus. Measles PA antibodies were detected three weeks after immunization. Neutralizing antibodies against JEV developed one week after inoculation, and EIA antibodies were detected three weeks after immunization. The measles AIK-C-based recombinant virus simultaneously induced measles and JEV immune responses, and may be a candidate for infant vaccines. Therefore, the present strategy of recombinant viruses based on a measles vaccine vector would be applicable to the platform for vaccine development.

  7. Towards the reconstruction of the shallow plumbing system of the Barombi Mbo Maar (Cameroon) Implications for diatreme growth processes of a polygenetic maar volcano

    NASA Astrophysics Data System (ADS)

    Chako Tchamabé, Boris; Ohba, Takeshi; Kereszturi, Gabor; Németh, Karoly; Aka, Festus Tongwa; Youmen, Dieudonné; Issa; Miyabuchi, Yasuo; Ooki, Seigo; Tanyileke, Gregory; Hell, Joseph Victor

    2015-08-01

    Understanding the mechanisms involved in the formation of maars and their diatreme growth processes has been a subject of contention. While there is no direct evidence of the presence of diatremes beneath most of the young maars, their existence is inferred based on the amount and type of country rocks excavated at different depths and deposited as pyroclastic ejecta around their craters. Properly tracing fragmented country rocks in ejecta to interpret their depths of origin and thus the depths of phreatomagmatic explosions require good and detailed information on the substrate geology that is generally lacking at many maars. As an alternative, this paper explores the role of juvenile components in deposits of a maar for understanding the cratering and growth of diatremes during maar-forming eruptions. Based on field investigations, pyroclast distribution, componentry and grain morphology examinations this study reports on the eruptive mechanisms that led to the formation of the Barombi Mbo Maar (BMM), a polygenetic maar volcano in Cameroon. The BMM consists of three diatremes that formed during distinct eruptive events and coalesced to produce an "amalgamated maar-diatreme". Two end-member types of eruption styles from the "dry" magmatic to the "wet" phreatomagmatic explosions governed the formation of the maar. In total, a minimum of 0.0658 km3 of magma (Dense Rock Equivalent corrected) was ejected based on calculation by applying interpolation techniques on digital elevation models obtained from SRTM30m data corrected by rock textural data collected from the field. The distribution of juvenile clasts throughout the stratigraphic sequence suggests a complex subsurface eruptive process, which originated probably within the uppermost part of the diatreme. From the distribution and morphology of juvenile clasts in the deposits, it is inferred that cratering and country rock excavation during the growth of each of the small diatremes developed mainly from shallow

  8. ELSA flood stack for MIS 2-3 from dry maar lakestructure Auel (Eifel/Germany)

    NASA Astrophysics Data System (ADS)

    Brunck, Heiko; Sirocko, Frank

    2015-04-01

    Lacustrine sediments are very sensitive to natural and anthropogenically enviromental changes. Thus, lake sediments are excellent climate archives and can be used for reconstructions of past precipitation and flood events. However, until now, there is no continous flood record for the entire last 60 000 years for Central Europe. The present study reconstructs paleo floods from event layers in the sediment, of dry maar lakestructure Auel (Eifel). This silted up basin has an inflow by a local stream. Accordingly the sedimentation rate is directly linked to runoff activity. The bioturbation was low so that event layers become visible, but varves are not preserved. The maar site is near to the town of Gerolstein in the Eifel; the core AU2 was drilled in the ELSA (Eifel Laminated Sediment archive) project and is 123m long. AU2 has the highest sedimentation rate of all ELSA cores, due to abundant fluvial input. The Eifel area is well suited to approximate Central European weather, because modern water level gauge data from Eifel rivers correlate with respective data from the Rhine (Wernli and Pfahl, 2009). Due to the high inflow into the maar, Auel has the highest number of botanical macro remains of all ELSA cores. These specific conditions explain why only in AU2 all 21 Greenland interstadials can be observed in the abundance of wood remains and the organic carbon concentration. In a final stratigraphic step the time series of Corg was tuned to the Greenland ice core chronology to link the central European landscape evolution directly to the Greenland climate curve (Svensson et al., 2008). Combined sedimentological, paleobotanical and geochemical data received from AU2 builds the foundation of the 14C based chronology. The synchronisation of the record with other cores is controlled by tephra time markers and pollen. Both are used to align the main cores of the ELSA project and construct an integrated age model for the last 220 000 years [b2k] (Förster and Sirocko

  9. Assessment of local seismic response of the Stracciacappa maar (Central Italy)

    NASA Astrophysics Data System (ADS)

    Moscatelli, Massimiliano; Simionato, Maurizio; Gaudiosi, Iolanda; Sottili, Gianluca; Pagliaroli, Alessandro; Sirianni, Pietro; Pileggi, Domenico; Avalle, Alessandra; Giallini, Silvia; Razzano, Roberto; Mancini, Marco; Vignaroli, Gianluca; Piscitelli, Sabatino; Bellanova, Jessica; Calamita, Giuseppe; Perrone, Angela; Lanzo, Giuseppe

    2016-04-01

    In this work, we face the definition of a subsoil model aimed at the local seismic response assessment of the Stracciacappa maar (Sabatini Volcanic District, central Italy) (e.g., De Rita and Zanetti, 1986; Marra et al., 2014). The pyroclastic succession of Stracciacappa records two main hydromagmatic eruptive phases ended about 0.09 Ma ago (e.g., Sottili et al., 2010). The preserved crater, with a diameter of about 1500 meters and a crater floor of about 30-40 m, hosted a lake until it was drained in AD 1834. In the framework of the cooperation between CNR IGAG and Italian Department of Civil Protection (DPC) of the Presidency of Council of Ministers (DPC funds 2014), a multidisciplinary approach including detailed stratigraphic and geophysical study has been carried out in the Stracciacappa maar and surrounding areas. New geological map and cross sections illustrate the complex geometric relationships between the thick pyroclastic surge succession, showing diffuse sandwave structures, and even meter-sized lava ballistic. A composite interdigitation between lacustrine and epiclastic debris sediments fills the crater floor. A continuous coring borehole was drilled inside the crater, 45 meters deep from the wellhead, with sampling of undisturbed samples. In addition, four MASW and one SCPTU test were carried out, in order to define the velocity profile of the s-waves within the lacustrine deposits. This Vs profile was then extended at higher depths by using the results of four 2D seismic passive arrays. Moreover, in order to define the resonance frequency of sedimentary covers via the HVSR technique, twenty-eight measurements were carried out with digital sensor Tromino® and seven measurements were performed with a Lennartz® Le-3D/5s sensor with Lennartz Marslite® digitizer. Finally, three electrical resistivity tomography tests, with a total length of about 3500 meters, were carried out with the purpose of constraining the subsoil model. Regarding the non linear

  10. Eifel maars: Quantitative shape characterization of juvenile ash particles (Eifel Volcanic Field, Germany)

    NASA Astrophysics Data System (ADS)

    Rausch, Juanita; Grobéty, Bernard; Vonlanthen, Pierre

    2015-01-01

    The Eifel region in western central Germany is the type locality for maar volcanism, which is classically interpreted to be the result of explosive eruptions due to shallow interaction between magma and external water (i.e. phreatomagmatic eruptions). Sedimentary structures, deposit features and particle morphology found in many maar deposits of the West Eifel Volcanic Field (WEVF), in contrast to deposits in the East Eifel Volcanic Field (EEVF), lack the diagnostic criteria of typical phreatomagmatic deposits. The aim of this study was to determine quantitatively the shape of WEVF and EEVF maar ash particles in order to infer the governing eruption style in Eifel maar volcanoes. The quantitative shape characterization was done by analyzing fractal dimensions of particle contours (125-250 μm sieve fraction) obtained from Scanning electron microscopy (SEM) and SEM micro-computed tomography (SEM micro-CT) images. The fractal analysis (dilation method) and the fractal spectrum technique confirmed that the WEVF and EEVF maar particles have contrasting multifractal shapes. Whereas the low small-scale dimensions of EEVF particles (Eppelsberg Green Unit) coincide with previously published values for phreatomagmatic particles, the WEVF particles (Meerfelder Maar, Pulvermaar and Ulmener Maar) have larger values indicating more complex small-scale features, which are characteristic for magmatic particles. These quantitative results are strengthening the qualitative microscopic observations, that the studied WEVF maar eruptions are rather dominated by magmatic processes. The different eruption styles in the two volcanic fields can be explained by the different geological and hydrological settings found in both regions and the different chemical compositions of the magmas.

  11. Modern stromatolites in a saline maar in the Western District of Victoria, Australia: a possible analogue for Precambrian marine carbonates

    NASA Astrophysics Data System (ADS)

    Lynch, J. E.; Wallace, M. W.

    2011-12-01

    Stromatolites and thrombolites are microbially-mediated, sedimentary structures of various size and morphology, found throughout the rock record. Although they do not always contain fossils of microbial cells, ancient stromatolitic structures are considered biogenic in origin and, therefore, evidence of early life. Modern, living stromatolites are found in lacustrine and marine environments and can provide a window in which to observe some of Earth's earliest biological processes. However, secular variation in marine chemistry over geological time means that modern marine settings are not always the best analogues for ancient carbonates. This study describes the occurrence of modern stromatolites in a saline, alkaline maar in Victoria, Australia. Dolomite is a principle carbonate mineral precipitating from this lake, an unusual and poorly understood occurrence in modern environments, but one that was common in the Precambrian. The peculiar lacustrine chemistry in this volcanic region may, therefore, provide a better analogue for Precambrian marine carbonates than modern marine environments. Several types of stromatolites/thrombolites are observed occurring around this maar. Living thrombolites grow just below the shoreline to ~60 cm below the surface of the water. They are nucleating on the cemented surfaces of older lake carbonates, as well as cattle skulls and fence wires that have become submerged. Distinct microbial mats are observed, the uppermost being cyanobacteria, followed by purple sulfur bacteria, and underlain by sulfate reducing bacteria. Older exposed stromatolites are more consolidated and have a more clearly defined laminated and columnar morphology. The thickness ranges from a few to 15 cm and each column is up to a centimeter in diameter. Together these give the surface of the rock a "bubbly" appearance. Along the shore, a sandy-gravel composed of stromatolite remnants has formed, indicating that wind-generated surface waves of substantial

  12. Orbital pacing of New Zealand hydroclimate during the Early Miocene: Biomarker and compound-specific isotope records from the Foulden Maar diatomite

    NASA Astrophysics Data System (ADS)

    Donatich, S.; D'Andrea, W. J.; Fox, B.; Lee, D. E.

    2012-12-01

    During the Early Miocene, atmospheric CO2 levels were similar to today yet global temperatures were warmer and large, stable polar ice sheets had not yet developed. Examining the climate dynamics of Early Miocene Earth requires quantitative paleoclimate records from terrestrial archives. Foulden Maar (45.5 °S, 170.2 °E) is an annually resolved maar lake deposit on South Island, New Zealand dating from the Oligocene/Miocene boundary. Anoxia in the basin fostered the preservation of a ~100m thick, annually laminated diatomite (the base of which has been dated to 23 ± 0.2 Ma using 40Ar/39Ar dating), and allowed for superb preservation of organic materials, including leaves, flowers, fish skeletons and insects. Here we examine the biomarker record and the hydrogen isotope composition (δD) of leaf waxes (n-alkanoic acids) preserved in Foulden Maar sediments over a ~100,000 year interval of the early Miocene. Leaf wax δD reflects δD of past environmental water and therefore allows hydroclimatic reconstruction at the site. Our record reveals large variations (up to 40 ‰) in leaf wax δD at obliquity and precession timescales and affords quantitative estimates of orbitally forced hydrologic changes during the Early Miocene. Sedimentary terpenoids reflect the composition of paleovegetation at the site and represent an independent proxy to complement pollen analyses throughout the diatomite. Additional biomarker-based analyses (including δ13C of leaf waxes) are currently underway, and up-to-date results will be presented.

  13. Identification of a Buried Late Cenozoic Maar-Diatreme Structure (North Moravia, Czech Republic)

    NASA Astrophysics Data System (ADS)

    Šešulka, Vojtěch; Sedláková, Iva; Bábek, OndŘej; PŘichystal, Antonín

    2015-01-01

    The maar-diatreme volcanic structure in the vicinity of the village of Lomnice near the town of Bruntál (North Moravia, Czech Republic) has been investigated using a set of geophysical methods including ground magnetometry, gravimetry and electrical resistivity tomography. The structure was detected by an aerial magnetic survey in the second half of the 20th century. Since its discovery only limited information about this buried structure has been available. The coherence of the magnetic anomaly of 190 nT and Bouguer anomaly of -4.7 mGal indicates a volcanic origin of the structure. The funnel-shaped maar-diatreme structure is filled with lacustrine clay and colluvium of Car-boniferous greywacke, which forms the country rock. The surface diameter of the structure is about 600 m, the depth is more than 400 m. The spatial association with other volcanic centers in the surroundings of the town of Bruntál infers the relative dating of the Lomnice maar. The phreatic eruption and maar-diatreme formation could be an indirect conse-quence of effusive activity of the nearby Velký Roudný volcano. The Lomnice structure is the first Plio-Pleistocene maar-diatreme ever described in North Moravia and Silesia.

  14. Simulating maar-diatreme volcanic systems in bench-scale experiments

    NASA Astrophysics Data System (ADS)

    Andrews, R. G.; White, J. D. L.; Dürig, T.; Zimanowski, B.

    2015-12-01

    Maar-diatreme eruptions are incompletely understood, and explanations for the processes involved in them have been debated for decades. This study extends bench-scale analogue experiments previously conducted on maar-diatreme systems and attempts to scale the results up to both field-scale experimentation and natural volcanic systems in order to produce a reconstructive toolkit for maar volcanoes. These experimental runs produced via multiple mechanisms complex deposits that match many features seen in natural maar-diatreme deposits. The runs include deeper single blasts, series of descending discrete blasts, and series of ascending blasts. Debris-jet inception and diatreme formation are indicated by this study to involve multiple types of granular fountains within diatreme deposits produced under varying initial conditions. The individual energies of blasts in multiple-blast series are not possible to infer from the final deposits. The depositional record of blast sequences can be ascertained from the proportion of fallback sedimentation versus maar ejecta rim material, the final crater size and the degree of overturning or slumping of accessory strata. Quantitatively, deeper blasts involve a roughly equal partitioning of energy into crater excavation energy versus mass movement of juvenile material, whereas shallower blasts expend a much greater proportion of energy in crater excavation.

  15. Proceedings of the 2nd Columbia River Basalt Symposium: Maar volcanoes

    NASA Technical Reports Server (NTRS)

    Waters, A. C.; Fisher, R. V.

    1971-01-01

    Examination of maar-type volcanic cones, including tuff rings, from more than 40 localities in western North America indicates that water had access to volcano orifices during their activity. The most convincing evidence is the abundance of sideromelane (chilled basaltic glass) or its palagonitic decomposition products in the ejecta. Moreover, the volcanoes which were examined erupted in basins that either contained surface water, or else they grew above highly permeable aquifers at shallow dept. Characteristic features of maar ejecta are continuous thin beds, undulations and antidunes characteristic of base surge stratification, abundant accretionary lapilli or mud-armored rock particles, bedding sags that show soft sediment deformation, and in the subaqueous parts of the maar ramparts, great piles of subtly graded thin lenses of hyaloclastic debris.

  16. Eruptive and structural controls on the evolution of Mexican maar volcanoes

    NASA Astrophysics Data System (ADS)

    Carrasco, G.; Ort, M. H.

    2013-05-01

    Although monogenetic volcanoes seem to have a very simple eruptive history, the geologic evolution of maar volcanoes is more complex because they involve a fluctuating explosive behavior due to rapid changes in how an ascending magma interacts with a source of external water. Maar volcanoes evolve in different ways depending on several factors such as magma extrusion rate, explosion depth variation, water/magma ratio, increasing cratering, viscosity, as well as characteristics of the country rock and structural features of the regional setting., Three main maar volcano fields, San Luis Potosí, Valle de Santiago and Serdán-Oriental, occur in central Mexico. In the first two fields, a strong tectonic control is evident for the general distribution of the volcanoes, while in the third case, a more local influence of shallow crustal fractures seems to control the migration of the explosion locus, causing elongated or craters shapes. Initial magma extrusion rates may have played an important role in producing different types of maar volcanoes. Also, the location of the explosions within the upper unconsolidated granular aquifer (brown tuff) or the deeper highly-fractured bedrock aquifer may control the efficiency of the explosions. Deepening and lateral migration of explosion loci are commonly observed in maar volcanoes, and lateral migration is strongly controlled by the regional stress regime. Eruptive styles vary from surge- and blast-dominated eruptions to alternating strombolian and vulcanian activity. Some show a drying-upward trend but others change from dry magmatic activity (hawaiian lava flows, followed by strombolian scoria) to highly fragmented hydromagmatic maar-forming explosions, which includes the periodic injection of juvenile material, particularly at the end of the eruptive phase.

  17. Miocene honey bees from the Randeck Maar of southwestern Germany (Hymenoptera, Apidae)

    PubMed Central

    Kotthoff, Ulrich; Wappler, Torsten; Engel, Michael S.

    2011-01-01

    Abstract The Miocene Randeck Maar (southwestern Germany) is one of the only sites with abundant material of fossil honey bees. The fauna has been the focus of much scrutiny by early authors who recognized multiple species or subspecies within the fauna. The history of work on the Randeck Maar is briefly reviewed and these fossils placed into context with other Tertiary and living species of the genus Apis Linnaeus (Apinae: Apini). Previously unrecorded specimens from Randeck Maar were compared with earlier series in an attempt to evaluate the observed variation. A morphometric analysis of forewing venation angles across representative Recent and Tertiary species of Apis as well as various non-Apini controls was undertaken to evaluate the distribution of variation in fossil honey bees. The resulting dendrogram shows considerable variation concerning the wing venation of Miocene Apini, but intergradation of other morphological characters reveals no clear pattern of separate species. This suggests that a single, highly variable species was present in Europe during the Miocene. The pattern also supports the notion that the multiple species and subspecies proposed by earlier authors for the Randeck Maar honey bee fauna are not valid, and all are accordingly recognized as Apis armbrusteri Zeuner. PMID:21594072

  18. An investigation of volcanic depressions. Part 3: Maars, tuff-rings, tuff-cones, and diatremes

    NASA Technical Reports Server (NTRS)

    Lorenz, V.; Mcbirney, A. R.; Williams, H.

    1970-01-01

    A classification of maars, tuff-rings, tuff-cones, and diatremes is given along with a summary of their lithologic and structural characteristics at the surface and at depth, and their probable manner of formation. Particular emphasis is placed on the roles of fluidization and groundwater.

  19. Arthropods from the Eocene Eckfelder Maar (Eifel, Germany) as a source for paleoecological information

    NASA Astrophysics Data System (ADS)

    Lutz, H.

    The arthropod-thanatocoenosis from the Middle-Eocene sediments of the Eckfelder Maar (Eifel, Germany) is characterized by a striking contrast between a highly diversified assemblage of terrestrial species on one hand and very few aquatic species on the other, hand. This most likely does not result from taphonomic biassing, but reflects a poor aquatic arthropod-community.

  20. Spatio-temporal variations in water quality of Nullah Aik-tributary of the river Chenab, Pakistan.

    PubMed

    Qadir, Abdul; Malik, Riffat Naseem; Husain, Syed Z

    2008-05-01

    This study reports the spatio-temporal changes in water quality of Nullah Aik, tributary of the Chenab River, Pakistan. Stream water samples were collected at seven sampling sites on seasonal basis from September 2004 to April 2006 and were analyzed for 24 water quality parameters. Most significant parameters which contributed in spatio-temporal variations were assessed by statistical techniques such as Hierarchical Agglomerative Cluster Analysis (HACA), Factor Analysis/Principal Components Analysis (FA/PCA), and Discriminant Function Analysis (DFA). HACA identified three different classes of sites: Relatively Unimpaired, Impaired and Less Impaired Regions on the basis of similarity among different physicochemical characteristics and pollutant level between the sampling sites. DFA produced the best results for identification of main variables for temporal and spatial analysis and separated eight parameters (DO, hardness, sulphides, K, Fe, Pb, Cr and Zn) that accounted 89.7% of total variations of spatial analysis. Temporal analysis using DFA separated six parameters (E.C., TDS, salinity, hardness, chlorides and Pb) that showed more than 84.6% of total temporal variation. FA/PCA identified six significant factors (sources) which were responsible for major variations in water quality dataset of Nullah Aik. The results signify that parameters identified by statistical analyses were responsible for water quality change and suggest the possibility of industrial, municipal and agricultural runoff, parent rock material contamination. The results suggest dire need for proper management measures to restore the water quality of this tributary for a healthy and promising aquatic ecosystem and also highlights its importance for objective ecological policy and decision making process.

  1. The ELSA-Vegetation-Stack: Reconstruction of Landscape Evolution Zones (LEZ) from laminated Eifel maar sediments of the last 60,000 years

    NASA Astrophysics Data System (ADS)

    Sirocko, F.; Knapp, H.; Dreher, F.; Förster, M. W.; Albert, J.; Brunck, H.; Veres, D.; Dietrich, S.; Zech, M.; Hambach, U.; Röhner, M.; Rudert, S.; Schwibus, K.; Adams, C.; Sigl, P.

    2016-07-01

    Laminated sediment records from several maar lakes and dry maar lakes of the Eifel (Germany) reveal the history of climate, weather, environment, vegetation, and land use in central Europe during the last 60,000 years. The time series of the last 30,000 years is based on a continuous varve counted chronology, the MIS3 section is tuned to the Greenland ice - both with independent age control from 14C dates. Total carbon, pollen and plant macrofossils are used to synthesize a vegetation-stack, which is used together with the stacks from seasonal varve formation, flood layers, eolian dust content and volcanic tephra layers to define Landscape Evolution Zones (LEZ). LEZ 1 encompasses the landscape dynamics of the last 6000 years with widespread human influence. The natural oak and hazel forests of the early Holocene back to 10,500 b2k define LEZ 2. LEZ 3, the late glacial between 10,500 and 14,700 b2k, shows the development of a boreal forest with abundant grass and shallow water biomass in the lakes. The maximum of the last glaciation (LEZ 4: 14,700-23,000 b2k) was characterized by sparse vegetation of moss and characeae. These sediments are generally devoid of clay and sand and reveal no indication of snow-meltwater events. Accordingly, the Last Glacial Maximum (LGM) must have been extremely arid in central Europe. The sediments of the subsequent LEZ 5 from 23,000-28,500 b2k preserve distinct layers of clay and coarse sand, which indicates running water with clay in suspension and ephemeral coarse-grained fluvial sediment discharge. Abundant Ranunculaceae macroremains (used for 14C dating), insects, moss and fungi sclerotia reflect a tundra environment during a time of frequent strong snowmelt events. Total carbon content, Betula-Pinus pollen and diatoms reach increased concentrations during Marine Isotope Stage (MIS) 3 interstadials that occurred between 28,500 and 36,500 b2k (LEZ 6). The entire MIS3 interstadials are well documented in the organic carbon record

  2. An Irregularly Shaped Maar in the Lunar Crater Volcanic Field, Nevada

    NASA Astrophysics Data System (ADS)

    Amin, J.; Valentine, G. A.

    2011-12-01

    A maar is a volcanic feature that is characterized by a central crater cut into the pre-eruptive ground and that is surrounded by an ejecta ring, and underlain by a diatreme [White and Ross, 2011]. Craters are typically bowl-shaped, and the intersection of the crater and the pre-eruptive ground typically are circular to elliptical. Some maars have more complex shapes; here we describe a maar informally named Bea's Crater, in the Lunar Crater Volcanic Field, Nevada. This maar has an irregular shape. Our study seeks to address whether this shape records a complex collapse history, coalescence of multiple eruptive vents, or other processes such as post-eruptive faulting. The largest dimension of the maar in plan view is 1.2 km. The crater depth (measured from the lowest point in the crater to the highest part of its rim) is 147 m, and the crater floor is 40 m below the surrounding terrain. The crater is surrounded by scoria cones or remnants of scoria cones. A tuff breccia distributed around the crater rim provides evidence for explosive magma-water interaction. This, and the lack of clear post-volcanic faults in the vicinity of the crater, indicates that eruptive processes rather than faulting created the crater. Detailed field mapping has revealed a complete eruptive sequence. The tuff breccia overlies, and is overlain by, magmatic products. This could be related to variations in the magma-water ratio throughout the eruption, with explosive magma-water interaction only occurring when the ratio is within a certain range. Furthermore, there are many large juvenile bombs within parts of the tuff breccia sequence. The juveniles may represent switching between phreatomagmatic and magmatic activity, or they could be the result of coeval magmatic activity from a separate vent. The scoria cone on the north east flank of the crater is the likely source of any coeval activity. It is impinging upon the crater floor, with the elevation of the impinging section much lower than

  3. The effects of the host-substrate properties on maar-diatreme volcanoes: experimental evidence

    NASA Astrophysics Data System (ADS)

    Macorps, Élodie; Graettinger, Alison H.; Valentine, Greg A.; Ross, Pierre-Simon; White, James D. L.; Sonder, Ingo

    2016-04-01

    While the relationship between the host-substrate properties and the formation of maar-diatreme volcanoes have been investigated in the past, it remains poorly understood. In order to establish the effects of the qualitative host-substrate properties on crater depth, diameter, morphological features, and sub-surface structures, we present a comparison of four campaigns of experiments that used small chemical explosives buried in various geological media to simulate the formation of maar-diatremes. Previous results from these experiments have shown that primary variations in craters and sub-surface structures are related to the scaled depth (physical depth divided by cube root of blast energy). Our study reveals that single explosions at optimal scaled depths in stronger host materials create the largest and deepest craters with steep walls and the highest crater rims. For single explosions at deeper than optimal scaled depths, the influence of material strength is less obvious and non-linear for crater depth, and non-existent for crater diameter, within the range of the experiments. For secondary and tertiary blasts, there are no apparent relationships between the material properties and the crater parameters. Instead, the presence of pre-existing craters influences the crater evolution. A general weakening of the materials after successive explosions can be observed, suggesting a possible decrease in the host-substrate influence even at optimal scaled depth. The results suggest that the influence of the host-substrate properties is important only in the early stage of a maar-diatreme (neglecting post-eruptive slumping into the open crater) and decreases as explosion numbers increase. Since maar-diatremes reflect eruptive histories that involve tens to hundreds of individual explosions, the influence of initial substrate properties on initial crater processes could potentially be completely lost in a natural system.

  4. Origin of the Joya Honda maar, San Luis Potosí, México

    NASA Astrophysics Data System (ADS)

    Aranda-Gómez, JoséJorge; Luhr, James F.

    1996-11-01

    Joya Honda is a Quaternary maar of unusual type from the Mexican Basin and Range Province. Its ~ 300-m-deep crater is excavated in Cretaceous limestones. The surrounding tephra deposit, which in places is > 100 m thick, begins with a series of weakly indurated pyroclastic-surge and -fall layers that we interpret as dry-surge deposits. These are overlain by the main sequence of strongly indurated, massive tuff breccias that we interpret as wet-surge deposits. Joya Honda formed subaerially from the interaction of groundwater with rapidly ascending intraplate-type basanitic magma carrying peridotitic mantle xenoliths. Local aquifer characteristics controlled the style of eruption and the nature of the deposits. Groundwater in the limestone-hosted aquifer beneath Joya Honda was apparently contained within solution-enhanced fractures. At the onset of the eruption, magma began to interact with a moderate amount of groundwater, producing the dry-surge deposits, which are typical of deposits found at many maars and tuff rings. As the eruption continued, the crater grew and the hydromagmatic blasts fractured the limestones around the explosion foci. A marked increase in the water/magma ratio of the system followed when a large fracture or a portion of the limestone with enhanced secondary permeability was intersected by the expanding crater. Subsequent phreatomagmatic explosions occurred in a system with groundwater flow rates several orders of magnitude larger than in the initial dry-surge stage. At the maar rim these wet eruptions led to the emplacement of massive tuff breccias through a combination of fallout, surges and mudflows. These steeply dipping tuff breccias are similar to deposits found at many tuff cones. Juvenile clasts in the near-vent deposits show marked upward increases in both hydration (palagonitization) and vesicularity. The increased palagonitization with height in the section appears to be a consequence of the overall increased wetness of the eruption

  5. The Sénèze maar (French Massif-Central): Hypothesis regarding a catastrophe occurring about 1.5 million years ago

    NASA Astrophysics Data System (ADS)

    Couthures, Jean

    1989-11-01

    A reconstruction, based on direct observations in the form of borings and paleontological digs, indicates repetitive catastrophes in the palaeo-lake of the Sénèze depression long after formation of the maar. This event is correlated with extensive slumping associated with erosion of the crater rim induced by a critical ring fault. K-Ar dating gives a lower limit of around 2.48 million years for the initial formation, but not the lapse of time between eruption and filling. According to drilling, sedimentology, and palynological analysis, the lake was functional between 2.3 and 1.3 million years ago, i.e., throughout the Tiglian and at the beginning of the Eburonian. The destruction of all animal life could only have been due to asphyxia, but probably resulted from a CO 2 release. All classes of animals, mainly mammals, were affected and subsequently died. They are found in the same levels in several fossiliferous beds, at the top of the lacustrine deposits and also in reworked debris from the crater rim.

  6. Reconstruction of Landscape Evolution Zones (LEZ) from laminated Eifel maar sediments of the last 60 000 years

    NASA Astrophysics Data System (ADS)

    Sirocko, Frank

    2016-04-01

    Tephra, eolian dust, organic carbon, pollen and botanical macroremains from the dry maar lake structures auf Auel and Dehner are used to synthesize and define Landscape Evolution Zones (LEZ) for the Eifel during the last 60 000 years. LEZ 1-3 reiterate the established succession of vegetation during the Holocene and late glacial. The maximum of the last glaciation (LEZ 4: 14 700 - 23 000 b2k) was characterized by extremely sparse vegetation of some moss and characeae, however, characterized by annual activity of eolian dust. These sediments are generally devoid of clay and sand and reveal no indication of snow-meltwater events; accordingly, the Last Glacial Maximum (LGM) must have been extremely arid in central Europe. The sediments of the subsequent LEZ 5 from 23 000 ‒ 28 500 b2k preserve however distinct layers of clay and coarse sand, which indicates running water with clay in suspension and ephemeral coarse grained fluvial sediment discharge; abundant Ranunculaceae macroremains (used for 14C dating), insects, moss and fungi sclerotia reflect a tundra environment during a time of frequent strong snow melt events. Total carbon content and Betula-Pinus pollen reach increased concentrations during all MIS 3 interstadials that occurred between 28 500 - 36 500 b2k (LEZ 6). Grass pollen and heliophytes indicate a steppe environment with scattered/patchy trees during the interstadials. The stadial phases of LEZ 6 reveal first activity of eolian dust deflation. The opening of the early MIS 3 forested landscape to a steppe occurred with the LEZ 7 - LEZ 6 transition at 36 500 b2k. This is the time when modern man arrived in central Europe; possibly because the vegetation change must have favoured the spread of horse, which was the favoured hunting prey of the modern humans. Accordingly, we postulate that the migration of the modern humans into central Europe could have been mainly driven by climate and vegetation change. The LEZ 7 encompassing the time interval from 36

  7. A new ELSA time series of tephra layers and paleobotanical evidence from laminated Eifel maar sediments covering the entire last 120,000 years

    NASA Astrophysics Data System (ADS)

    Sirocko, Frank; Knapp, Hannes; Klee, Marlies; Rothacker, Leo; Kromer, Bernd

    2014-05-01

    The ELSA Project has drilled a total of 50 sediment cores (2000 m of laminated lake sediment) from Eifel maar lakes and dry maar structures during the last 15 years. These records have been dated using 7 different methods, including 370 14C dates. Ten records reveal the established palynological succession of trees during the Holocene down to the Laacher See Tephra, which is used for synchronization with seven more recently drilled laminated sediment cores, which all are 14C-dated too and analyzed for tephra, pollen and paleobotanical macroremains. The seven newly established records reveal a continuous MIS2 section with mosses, ostracods and characea oogonia. They show that the 28.000 - 40.000 BP has witnessed an open landscape dominated by grass, but with rhythmic spread of conifer trees following the Greenland interstadial/succession. Seeds of Ranunculae provide excellent material for 14C dating. Even deciduous trees are present in small amounts until 28.000 BP. The time from 48.000 to 40.000 BP is characterized by a pronounced transition from the open landscape to an early MIS3 spruce (Picea) dominated forest during Greenland Interstadial GI17-14. Modern man apparently arrived at the end of this principal vegetation change near 40,000 BP. Volcanic activity in the Eifel had a stable and pronounced recurrence from 55,000 - 30,000 BP every 4000 years, but commenced with the beginning of MIS2. This landscape evolution with a forested early MIS3 is quite different to peat and sediment records from Netherlands/ Northern Germany/Scandinavia/ Poland, but is similar to conditions in parts of Switzerland. We address the early MIS3 forest to the nearby continuously moist soils and warm conditions in the nearby Mosel valley, i.e. on those stands where wine is growing today, and which most likely had served as a local refugia even for deciduous trees during MIS4 and MIS3. The MIS5 sections of the presented ELSA records reach down at least to the beginning of MIS5d near 118

  8. Hydrovolcanic evolution of the Joya Prieta maar, San Luis Potosí, northeast Mexico

    NASA Astrophysics Data System (ADS)

    Davila-Harris, P.; Aranda-Gomez, J. J.; Carrasco, G.

    2013-05-01

    The Joya Prieta is a Quaternary maar volcano emplaced at the western sector of the Sierra Madre Oriental fold and thrust belt. The crater is located at the axis of an open Laramide fold with a N20°W axis trend. It is the most easterly structure of the Santo Domingo Group, a cluster of intraplate maars and tuff-rings northeast of San Luis Potosí. A characteristic feature of these maars is that they are emplaced in close relationship with anticlines, exposing impressive inner crater walls of folded strata. In the Joya Prieta maar, the calcareous basement rocks are clearly exposed and unconformably overlain by the volcanic succession. A generalized stratigraphic sequence registers, from base to top, olivine-bearing basalt lava resting unconformably atop El Abra Formation limestone. The lava is overlain by thick and oxidized scoria and spatter agglomerate that grades into a moderately sorted spatter-fall layer with pervasive palagonite alteration. In direct contact with no evidence of reworking, pedogenesis or remobilization, the maar-forming sequence starts with parallel-stratified fall layers of altered basaltic pumice and scoria, with lava and limestone lithic clasts. This fall deposit marks the influx of xenocrystals and xenoliths, widely documented in previous works; they comprise mainly kaersutite mega crystals and spinel lherzolite respectively. The proximal fall deposit is divided into two thick layers by an indurated ash-tuff bed with pellets and single-rimmed accretionary lapilli. The upper layer of this fall deposit passes gradually onto an alternation of lapilli-sized layers with parallel ash-tuff horizons until it grades into cross-stratified, lithic-rich lapilli-tuff. The heterolithologic lapilli tuff is cemented on a fine ash matrix with palagonized juvenile clasts and abundant lava, shale and limestone lithics exhibiting a plethora of lithofacies in the like of parallel-bedded tuff, low-angle cross-bedded tuff and massive strata. This passes gradually

  9. Physical experiments of land subsidence within a maar crater: insights for porosity variations and fracture localization

    NASA Astrophysics Data System (ADS)

    Cerca, M.; Rocha, L.; Carreón-Freyre, D.; Aranda, J.

    2015-11-01

    We present the results of a series of physical models aiming to reproduce rapid subsidence (at least 25 m in 30 years) observed in the sediments of a maar crater caused by extraction of groundwater in the interconnected adjacent aquifer. The model considered plausible variations in the geometry of the crater basement and the measured rate of groundwater extraction (1 m per year in the time interval from 2005 to 2011) in 15 wells located around the structure. The experiments were built within a rigid plastic bowl in which the sediments and rocks of the maar sequence were modeled using different materials: (a) plasticine for the rigid country rock, (b) gravel for the fractured country rock forming the diatreme fill and, (c) water saturated hollow glass microbeads for the lacustrine sedimentary fill of the crater. Water table was maintained initially at the surface of the sediments and then was allowed to flow through a hole made at the base of the rigid bowl. Water extraction provoked a sequence of gentle deformation, fracturing, and faulting of the surface in all the experiments. Vertical as well as lateral displacements were observed in the surface of the experiments. We discuss the results of 2 representative models. The model results reproduced the main geometry of the ring faults affecting the crater sediments and helps to explain the diversity of structures observed in relation with the diatreme geometry. The surface of the models was monitored continuously with an optical interferometric technique called structured light projection. Images collected at nearly constant time intervals were analyzed using the ZEBRA software and the obtained interferometric pairs permitted to analyze the full field subsidence in the model (submilimetric vertical displacements). The experiments were conducted at a continuous flow rate extraction and show a also a linear subsidence rate. Comparison among the results of the physical models and the fault system associated to

  10. Relationship between Bajo Pobre and Chon Aike formations (Deseado Massif, Patagonia, Argentina):a melt inclusions study

    NASA Astrophysics Data System (ADS)

    Busà, T.; Bellieni, G.; Fernandez, R.; Hecheveste, H.; Piccirillo, E. M.

    2003-04-01

    The Deseado Massif covers the centre-east of the Santa Cruz Province, in the extra-Andean Patagonia. Although the Deseado Massif is mainly composed of silicic volcanic rocks (Chon Aike Formation, CA; 151.5 ±0.5 - 177.8 ±0.4 Ma), mafic and intermediate volcanites (Bajo Pobre Formation, BP; 152.7 ±0.5 and 164 ±0.3 Ma) outcrop largely in the central part of the Massif. In this paper quarz-trapped melt inclusions (rhyolitic in composition) from selected samples of the BP and the CA are analysed. On the basis of major elements content, for BP the sequence from andesite (BP whole rock) to ryholite (trapped as inclusions in quartz) can be modelled by simple fractional crystallisation of ortho- and clinopyroxene, plagioclase, quartz and apatite. As regards trace elements, a good calculated/measured ratio (around 1 ±0.2) is obtained assuming only a relatively high apatite fractionation. Since the apatite fractionation amount is not acceptable for major elements, the evolution of BP Formation cannot be modelled by a simple process of fractional crystallisation, and a contamination process probably occurred. The sequence from BP to CA cannot be modelled by fractional crystallisation. 30% batch melting of BP andesite (BP whole rock) produces a magma from which the CA ryholites (trapped as inclusions in quartz) can be obtained by Rayleigh fractional crystallisation of ortho- and clinopyroxene, plagioclase, magnetite, quartz, apatite and small amounts of zircon and minor allanite. Since the latter one was not observed in the analysed sample, a contamination process during magma evolution cannot be completely excluded. Finally, on the basis of the different trace elements concentration (Nb anomaly, different content in LILE, B/Be and B/Nb), it is possible to suppose that, at the time of the BP and CA emplacement, a changing in the tectonic setting, from subduction to a lithospheric extension, was active.

  11. Investigation of a Tertiary maar structure using three-dimensional resistivity imaging

    NASA Astrophysics Data System (ADS)

    Brunner, Ingolf; Friedel, Sven; Jacobs, Franz; Danckwardt, Erik

    1999-03-01

    This paper presents the application of the electrical resistivity tomography (ERT) method to the investigation of the Tertiary maar structure of Baruth (Germany) known from previous gravimetric surveys. ERT was applied to support the optimum location for a palaeoclimatological drill hole. Special modifications of data acquisition, signal processing and inversion are introduced to adapt the method of ERT to the special requirements for the 3-D investigation of structures with horizontal extensions of 1 km or more. More than 5000 dipole-dipole combinations were recorded at three concentric circular electrode arrangements using stand-alone transient data acquisition systems (RefTek). We present a fast approximate imaging technique based on the simultaneous iterative reconstruction technique (SIRT). As the complete calculation of the inverse Frechét matrix is avoided, the algorithm is especially suitable for large data and model spaces, where complete inversion is beyond the limits of available computing hardware. The single-step method is applicable to arbitrary irregular electrode layouts. Synthetic tests show that the imaging procedure reconstructs the main features of the subsurface. A low-resistivity body could be interpreted as limnic sediments filling the interior of the Tertiary maar crater. Considering the horizontal resistivity gradient, estimates for the lateral and depth extents of the structure were made. An optimum position for a palaeoclimatological borehole was found, and was in good agreement with the gravimetric minimum.

  12. Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring

    USGS Publications Warehouse

    Evans, William C.; Bergfeld, D.; McGimsey, R.G.; Hunt, A.G.

    2009-01-01

    Diffuse CO2 efflux near the Ukinrek Maars, two small volcanic craters that formed in 1977 in a remote part of the Alaska Peninsula, was investigated using accumulation chamber measurements. High CO2 efflux, in many places exceeding 1000 g m-2 d-1, was found in conspicuous zones of plant damage or kill that cover 30,000-50,000 m2 in area. Total diffuse CO2 emission was estimated at 21-44 t d-1. Gas vents 3-km away at The Gas Rocks produce 0.5 t d-1 of CO2 that probably derives from the Ukinrek Maars basalt based on similar ??13C values (???-6???), 3He/4He ratios (5.9-7.2 RA), and CO2/3He ratios (1-2 ?? 109) in the two areas. A lower 3He/4He ratio (2.7 RA) and much higher CO2/3He ratio (9 ?? 1010) in gas from the nearest arc-front volcanic center (Mount Peulik/Ugashik) provide a useful comparison. The large diffuse CO2 emission at Ukinrek has important implications for magmatic degassing, subsurface gas transport, and local toxicity hazards. Gas-water-rock interactions play a major role in the location, magnitude and chemistry of the emissions.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  14. The potential of Pleistocene volcanism for constraining the palaeo-environmental history of the Arabian peninsula: 40Ar/39Ar dating of Al Wahbah maar crater, Harrat Kishb, Saudi Arabia.

    NASA Astrophysics Data System (ADS)

    Abdel Wahab, Antar; Stuart, Finlay M.; Abul Maaty, Mostafa; Awad, Hesham; Kafafy, Aziz

    2013-04-01

    The Arabian peninsula is a critical region for early human migration out of Africa. Pleistocene climatic conditions have fluctuated between wet and dry extremes several times and have had a profound effect on environment and, likely, the development of human populations in the region. However, absolute chronological constraints on regional environmental and climatic changes are poor. The western margin of the Arabian peninsula is covered by 180,000 km2 of Cenozoic to Recent lava flows and related volcanic rocks that record palaeo-climatic conditions. Precise dating of these volcanic rocks has the potential to refine the climatic- environmental evolution of the region. We report a detailed geological and geochronological study of Al Wahbah maar crater (~2.2 km diameter, ~250 m deep) in Harrat Kishb, Saudi Arabia. It formed during a phreatomagmatic explosion that dissected a scoria cone on the northern wall of the crater that exposes a dolerite plug that was intruded immediately prior to crater formation. Pillow lavas at the base of the cone demonstrate that the phreatomagmatic eruption occurred during interaction between magma and a shallow lake or river, rather than groundwater. The 40Ar/39Ar age of dolerite plug (1.147 ± 0.004 Ma) reflects the time that Al Wahbah maar crater formed. More importantly it puts a firm date on the presence of abundant surface water. This study provides constraints on the timing of humid climatic conditions in the region and suggests that the Quaternary basaltic volcanism that stretches the length of the western side of the Arabian peninsula may prove to be useful for establishing the timing of palaeoclimatic changes.

  15. Catalog of crater lakes from Costa Rica

    NASA Astrophysics Data System (ADS)

    Ramirez, C. J.; Mora-Amador, R.; González, G.

    2010-12-01

    Costa Rica has a diversity of volcanic crater lakes that can be classified into two groups: hot and cold lakes. The country contains at least 5% of the world's hot lakes. Costa Rica has 2 hot hyperacidic lakes, both of them on active volcanoes, the Rincón de la Vieja (38.0°C, pH = 0 - 1) and the Poás Laguna Caliente (36.1°C - 56°C, pH = 0.55 - 0.74), nowadays the Poás hot lake is the most active crater lake in the world, with more than 200 eruptions only on 2010. One of the most studied cold crater lakes is Irazú (13°C, pH = 3.5), that used to contain bubbling and clear areas of upwelling involving CO2 liberation and subaqueous fumaroles with temperatures up to 50°C, but since 2005 the lake presents an important descend until April 2010 when it disappeared. On February 9, 2003, Irazú's lake underwent a drastic change of color, from clear green to mustard with reddish loops, similar to the color of the waters of Lake Nyos after the gas burst of August 1986. Other studied cold lakes include Botos, Chato, and Tenorio, all at the summit of Quaternary volcanoes as well as Barva and Danta, located in recent pyroclastic cones. Some cold lakes are located in Holocene maar-type explosion craters, among them are Congo, Bosque Alegre, Hule, and Río Cuarto. These last two have undergone repeated rapid reddish color changes over the last 10 years, in association with fish kills and the liberation of apparently sulfurous scents. On March 2010, University of Costa Rica was the host of the 7th Workshop on Volcanic Lakes, part of the Commission of Volcanic Lakes of the IAVCEI, 51 participants from 14 countries attended the workshop; they presented 27 talks and 17 posters, also they visited and sample 4 of the lakes mentioned above (Botos, Irazú, Río Cuarto and Hule). Level of Study: 1: few or no data, 2: regular, 3: acceptable

  16. High richness of insect herbivory from the early Miocene Hindon Maar crater, Otago, New Zealand

    PubMed Central

    Lee, Daphne E.; Wappler, Torsten

    2017-01-01

    Plants and insects are key components of terrestrial ecosystems and insect herbivory is the most important type of interaction in these ecosystems. This study presents the first analysis of associations between plants and insects for the early Miocene Hindon Maar fossil lagerstätte, Otago, New Zealand. A total of 584 fossil angiosperm leaves representing 24 morphotypes were examined to determine the presence or absence of insect damage types. Of these leaves, 73% show signs of insect damage; they comprise 821 occurrences of damage from 87 damage types representing all eight functional feeding groups. In comparison to other fossil localities, the Hindon leaves display a high abundance of insect damage and a high diversity of damage types. Leaves of Nothofagus(southern beech), the dominant angiosperm in the fossil assemblage, exhibit a similar leaf damage pattern to leaves from the nearby mid to late Miocene Dunedin Volcano Group sites but display a more diverse spectrum and much higher percentage of herbivory damage than a comparable dataset of leaves from Palaeocene and Eocene sites in the Antarctic Peninsula. PMID:28224051

  17. Terminal Pleistocene to early Holocene volcanic eruptions at Zuni Salt Lake, west-central New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Onken, Jill; Forman, Steven

    2017-01-01

    Zuni Salt Lake (ZSL) is a large maar in the Red Hill-Quemado volcanic field located in west-central New Mexico in the southwestern USA. Stratigraphic analysis of sections in and around the maar, coupled with optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C dating, indicate that ZSL volcanic activity occurred between ˜13.4 and 9.9 ka and was most likely confined to a ≤500-year interval sometime between ˜12.3 and 11.0 ka. The basal volcanic unit consists of locally widespread basaltic ash fallout interpreted to represent a violent or wind-aided strombolian eruption tentatively attributed to Cerro Pomo, a scoria cone ˜10 km south of ZSL. Subsequent eruptions emanated from vents near or within the present-day ZSL maar crater. Strombolian eruptions of multiple spatter and scoria cones produced basaltic lava and scoria lapilli fallout. Next, a phreatomagmatic eruption created the maar crater and surrounding tephra rim and apron. ZSL eruptions ended with strombolian eruptions that formed three scoria cones on the crater floor. The revised age range of ZSL is younger and more precise than the 190-24 ka 2-sigma age range derived from previous argon dating. This implies that other morphologically youthful, argon-dated volcanoes on the southern margin of the Colorado Plateau might be substantially younger than previously reported.

  18. Basaltic maar-diatreme volcanism in the Lower Carboniferous of the Limerick Basin (SW Ireland)

    NASA Astrophysics Data System (ADS)

    Elliott, H. A. L.; Gernon, T. M.; Roberts, S.; Hewson, C.

    2015-05-01

    Lead-zinc exploration drilling within the Limerick Basin (SW Ireland) has revealed the deep internal architecture and extra-crater deposits of five alkali-basaltic maar-diatremes. These were emplaced as part of a regional north-east south-west tectonomagmatic trend during the Lower Carboniferous Period. Field relationships and textural observations suggest that the diatremes erupted into a shallow submarine environment. Limerick trace element data indicates a genetic relationship between the diatremes and extra-crater successions of the Knockroe Formation, which records multiple diatreme filling and emptying cycles. Deposition was controlled largely by bathymetry defined by the surrounding Waulsortian carbonate mounds. An initial non-diatreme forming eruption stage occurred at the water-sediment interface, with magma-water interaction prevented by high magma ascent rates. This was followed by seawater incursion and the onset of phreatomagmatic activity. Magma-water interaction generated poorly vesicular blocky clasts, although the co-occurrence of plastically deformed and highly vesicular clasts indicate that phreatomagmatic and magmatic processes were not mutually exclusive. At a later stage, the diatreme filled with a slurry of juvenile lapilli and country rock lithic clasts, homogenised by the action of debris jets. The resulting extra-crater deposits eventually emerged above sea level, so that water ingress significantly declined, and late-stage magmatic processes became dominant. These deposits, largely confined to the deep vents, incorporate high concentrations of partially sintered globular and large `raggy' lapilli showing evidence for heat retention. Our study provides new insights into the dynamics and evolution of basaltic diatremes erupting into a shallow water (20-120 m) submarine environment.

  19. Late-stage magmatic processes at Albano Maar, Colli Albani, Italy: insights from FTIR analysis of leucites

    NASA Astrophysics Data System (ADS)

    Cross, J. K.; Roberge, J.; Smith, V.; Giordano, G.; Tomlinson, E.; Menzies, M. A.

    2011-12-01

    The recently erupted Albano Maar, one of the Via dei Laghi phreatomagmatic eruptions of Colli Albani, Italy have eruptive deposits that are K-foiditic (9wt% K2O) and silica under-saturated (48-52wt% SiO2). These compositions suggest the melts are low viscosity [1, 2], but they fuelled very explosive eruptions, namely the widespread large Peperino ignimbrite (phreato-Plinian) deposits. Therefore a question asked by researchers is how could these melts explode and would they, if they had not interacted with groundwater? Experimental work has shown that the melt chemistries at Colli Albani require a volatile saturated system [3]. Consequently the CO2 and H2O content of the melts are critical to understanding the petrogenetic processes at Albano Maar. Since the juvenile tephra clasts exhibit extensive late stage micro-crystallization (mainly leucite), analysis of glass is difficult and not representative as the majority of the volatile components may have exsolved from the melt. Melt inclusions are also commonly recrystallized and often leaky so here we unravel the complex volatile histories of the melts using the abundant leucite crystals, which have been shown to contain magmatic water in recent studies [4]. FTIR analysis of leucite phenocrysts and microcrysts within juvenile tephra clasts (syn-eruptive) of all the erupted units at Albano Maar provide an interesting insight into volatile variations and record a late stage CO2 fluxing event, which would have contributed to the explosive nature of the eruptions. This study has also allowed for an increased understanding of the nominally anhydrous minerals (NAMs) that crucially record volatile speciation and fluxing in high level magmatic systems. [1] Freda et al., 2006, Bul Vol, 68, pp567-591 [2] Cross et al., 2011 IUGG abs [3] Freda et al., 2008, Lithos, pp397-415 [4] Ventura et al., 2008, Am Min, 93, pp1538-1544

  20. 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)…

  1. Modelling historical lake levels and recent climate change at three closed lakes, Western Victoria, Australia (c.1840 1990)

    NASA Astrophysics Data System (ADS)

    Jones, R. N.; McMahon, T. A.; Bowler, J. M.

    2001-06-01

    Lake levels of three hydrologically closed maar lakes, Lakes Keilambete, Gnotuk and Bullenmerri in Western Victoria, Australia, have declined since the first recorded observations in 1841. High levels were previously sustained for several centuries with the lakes in climatic equilibrium. Historical survey and field investigations provide a detailed picture of both historical land-use changes and of the geological and hydrogeological influences on the water budget. Groundwater components include baseflow from deep percolation within the catchment and discharge from a surrounding low-yield aquifer. A perched watertable at Lake Keilambete helped maintain high lake levels. Climate records back to 1859 were reconstructed; inhomogeneities from 1863 were removed creating a high quality instrumental record. A water balance model simulating the historical decline demonstrates important features. (1) Regional climate expressed as a lake precipitation/evaporation ( P/ E) ratio remains the over-riding influence on lake levels. (2) The lakes fell in response to a change in climate. (3) This climate change pre-dated instrumental records. (4) Land-use change did not contribute to declining water levels. The fall in water levels was initiated by a decrease in P/ E ratio from a pre-1840 value of 0.94-0.96 to a historical value of 0.79. This change probably involved a decrease in rainfall, possibly associated with increases in solar radiation and decreases in cloud cover. Temperature ( T) may also have increased but the likelihood of an altered temperature-evaporation relationship means that a quantified estimate is not possible. The ability of the lakes to reflect climate independently of land-use change is highly unusual, both in Australia and elsewhere. These lakes provide a rare opportunity to discriminate between human impact on regional hydrology and climate change.

  2. Characterization of potential sources of magnetic anomalies within the crust in a tectonically active region: Amphibolites and migmatites from Potrillo Maar, New Mexico

    NASA Technical Reports Server (NTRS)

    Spear, F. S.; Padovanni, E.

    1985-01-01

    The purpose was to characterize the oxide mineralogy and petrology of samples collected from Potrillo Maar, New Mexico with the goal of explaining the magnetic anamoly that is observed over this region from remote sensing. Potrillo Maar is a diatreme that has brought rocks from all depths in the crust to the surface almost instantaneously. The samples are therefore thought to be representative of the crust as it exists today below this portion of the Rio Grande Rift. It is generally believed that oxide minerals (magnetite, hematite, etc.) are responsible for the magnetic signature of the crust. The samples from Portillo Maar therefore offer a unique opportunity to examine the magnetic mineralogy of the entire crust. The results indicate that the magnetic anamoly observed over Rio Grande Rift may be consequence of the tectonic activity that caused mylonitization of the rocks and allowed the infiltration of oxidizing fluids.

  3. Early volcanological research in the Vulkaneifel, Germany, the classic region of maar-diatreme volcanoes: the years 1774-1865

    NASA Astrophysics Data System (ADS)

    Lutz, Herbert; Lorenz, Volker

    2013-08-01

    The Vulkaneifel (Volcanic West Eifel) in the western part of the Rhenish Slate Mountains, Germany, played a major role in the early history of volcanology in general and especially so with respect to the recognition and volcanology of maar-diatreme volcanoes. In 1819, the volcano term "maar" was introduced into the scientific literature by Johann Steininger, a teacher from Trier (Treves) who established the Vulkaneifel as the type region for this kind of volcano. At that time, only a few pioneers—in the earliest days practically all of them were amateurs—had visited this part of western Central Europe in the late eighteenth and earliest nineteenth century. Despite many making important contributions to knowledge of volcanoes, not all were appreciated. In consequence, only in the second half of the twentieth century did new ideas and concepts concerning volcanism in general and phreatomagmatic activity in particular arise that were not previously presented by these pioneers. Their pathbreaking ideas have so far been mostly ignored, we feel, because of the old literature's limited availability. This paper tries to shed new light on these trailblazers. A selection of early geological maps of the Vulkaneifel and its neighbouring regions demonstrates the enormous advancements that had been achieved during those early days, to a large extent, in this part of Western Europe.

  4. The Prodigies of The Albano Lake During Roman Age and Natural Hazard Assessment At Roma, Italy.

    NASA Astrophysics Data System (ADS)

    Funiciello, R.; Giordano, G.; de Rita, D.

    Roma is built just 20 km to the northwest of the Pleistocene Colli Albani volcano, but is believed not exposed to relevant natural hazards, except for the Tiber river flood- ings, and local amplification of seismic waves from distal earthquakes. This belief has generally induced modern historians and geologists to discard as SmythologicalT the & cedil;many references to natural prodigies that are reported by many Roman-age historians. Recent studies have demonstrated that the Albano maar, the youngest volcanic cen- tre of the Colli Albani volcano and presently filled by a 175 m deep lake, protracted its activity to the Holocene triggering several catastrophic lahar events, likely related to lake withdrawal, the deposits of which are exposed to the southwest of Roma and reach its periphery. This finding youngs the history of the volcano and makes it rele- vant to pre-historic settlements, which ScarefullyT avoided the Albano maar slopes up & cedil;to the Bronze age. What is still unknown, though, is whether the lake experienced such fluctuations and overspills during historic times. Several Roman authors such as Ti- tus Livius, Dionigi d'Alicarnasso, Plutarco, Germanico, and many others wrote about the then well known 398 BC prodigious event, when, during the war between Roma and the Etruscan city of Veio, the gods anger caused the sudden rise and overspill of the Albano lake, reported as unrelated to climatic events, and the destructive flooding of the countryside. After that event Romans actually built a tunnel-drain which still operates regulating the lake level at 293 m a.s.l., 70 m below the maar rim elevation. Should those chronicles be truthful, we can join the geologic observation of Holocene lahar deposits from lake withdrawal with historical lake withdrawals, reassessing the natural hazard for the city of Roma under a point of view never explored before. This paper carefully explores the historical credibility of the 398 BC lake overspill event and its

  5. Interannual and orbital-scale climate variability in the early Miocene: Compound-specific D/H records from the Foulden Maar Diatomite, New Zealand

    NASA Astrophysics Data System (ADS)

    D'Andrea, W. J.; Fox, B.; Lee, D.

    2013-12-01

    The El Niño-Southern Oscillation (ENSO) cycle is the most important interannual climate variation on Earth and has far reaching impacts on global climate. However, the behavior of ENSO over orbital timescales and under different global climate states is poorly understood and controversial. It has been proposed that ENSO behaved much differently in the past, perhaps even transitioning toward a permanent El Niño-like state. Our understanding of the ENSO response to orbital variations and the background climate state is incomplete and there are fundamental flaws in our knowledge of this important player in Earth's climate system. Here we present a 100,000-yr long compound-specific hydrogen isotope (D/H) record along with varve thickness data that document southern New Zealand (46°S, 170°E) climate in the early Miocene; the results suggest modulation of ENSO by Earth's orbital changes at precession (~22,000 year) and semiprecession (~11,000 year) timescales. Our data come from analyses of the Foulden Maar Diatomite, an annually laminated sediment sequence from an early Miocene freshwater lake in Otago, New Zealand. The diatomite contains approximately 100,000 dark-light couplets interpreted as biogenic varves, and has exquisite preservation of leaves, flowers, insects, diatom frustules and n-alkanoic acids derived from leaf waxes and algae. D/H records from n-alkanoic acids reveal large variations corresponding to precession (~22,000 yrs) and semi-precession (~11,000 yrs) timescales that reflect large paleohydrological changes. Varve thickness records reveal spectral power that exceeds the 99% confidence limit in the 3 to 7-yr band, and indicate that ENSO was an important driver of interannual climate variability in southern New Zealand during the early Miocene. We propose that the semiprecession-paced hydrologic changes represented by our compound-specific D/H record document the modulation of ENSO by variations in Earth's orbital configuration; specifically, that

  6. Lake Tahoe

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate change, Lake Tahoe Total Maximum Daily Load (TMDL), EPA-sponsored projects, list of partner agencies.

  7. Water chemistry of lakes related to active and inactive Mexican volcanoes

    NASA Astrophysics Data System (ADS)

    Armienta, María Aurora; Vilaclara, Gloria; De la Cruz-Reyna, Servando; Ramos, Silvia; Ceniceros, Nora; Cruz, Olivia; Aguayo, Alejandra; Arcega-Cabrera, Flor

    2008-12-01

    Water chemistry of crater lakes, maars and water reservoirs linked to some Mexican volcanoes within and outside the Mexican Volcanic Belt has been determined for several years and examined regarding environmental and volcanic factors. All the analyzed lakes are relatively small with a maximum depth of 65 m, and are located in regions with different climates, from semi-arid to very humid, with altitudes ranging from 100 to more than 4000 m a.s.l. Crater lakes in active volcanoes (El Chichón, Popocatépetl) have very low pH, moderate to high temperatures and major ion concentrations varying with the level of volcanic unrest. Lakes in sub-arid and temperate-arid regions (like maars in Puebla and Guanajuato states) show high alkalinity and pH, with bicarbonate/carbonate, chloride, sodium and magnesium as predominant ions. Lakes located in humid climates (Central Michoacán and Veracruz state) have low mineralization and near-neutral pH values. In general, conservative dissolved ions and conductivity appear to be mostly controlled by precipitation/evaporation and by the ionic concentration of groundwater inputs. Calcium, magnesium, sulfate concentrations and pH are strongly influenced by volcanic-rock or volcanic gas interactions with water. The influence of low-level volcanic activity on crater lakes may be obscured by water-rock interactions, and climatic factors. One of the aims of this paper is to define the relative influence of these factors searching for a reference frame to recognize the early volcanic precursors in volcano-related lakes.

  8. A first Late Glacial and Early Holocene coupled 18O and 2H biomarker isotope record from Gemuendener Maar, Germany

    NASA Astrophysics Data System (ADS)

    Zech, Michael; Bromm, Tobias; Hepp, Johannes; Benesch, Marianne; Sirocko, Frank; Glaser, Bruno; Zech, Roland

    2015-04-01

    During the last years, we developed a method for compound-specific d18O analyses of hemicellulose-derived sugars from plants, soils and sediment archives (Zech and Glaser, 2009; Zech et al., 2014). The coupling of respective d18O sugar results with d2H alkane results from paleosol and sediment climate archives proved to be a valuable innovative approach towards quantitative paleoclimate reconstruction (Hepp et al., 2014; Zech et al., 2013). Here we present a first coupled d18O sugar and d2H alkane biomarker record obtained for Late Glacial and Early Holocene sediments from the Gemuendener Maar in the Eifel, Germany. The d18O sugar biomarker record resembles the d18O ice core records of Greenland. The coupling with the d2H alkane biomarker results allows drawing further more quantitative paleocimate information in terms of (i) paleohumidity and (ii) d18O of paleoprecipitation.

  9. Geochemistry and eruptive behaviour of the Finca la Nava maar volcano (Campo de Calatrava, south-central Spain)

    NASA Astrophysics Data System (ADS)

    Lierenfeld, Matthias Bernhard; Mattsson, Hannes B.

    2015-10-01

    Here we present a detailed investigation into the geochemistry and the excavational/depositional processes involved in the maar-diatreme forming Finca la Nava (FlN) eruption in south-central Spain. Bulk rock compositions of hand-picked juvenile fragments indicate derivation of the FIN magma from a garnet-bearing mantle source, which has subsequently been overprinted in bulk rock samples by incorporation of a combination of spinel-bearing peridotites and upper-crustal lithics (i.e. quartzites and slates). The dominating phenocryst assemblage with clinopyroxene, olivine, amphibole and phlogopite points to the classification of the juvenile magma as being olivine melilititic in composition. Ascent through the lithosphere was rapid as indicated by the calculations of settling rates of mantle peridotites (~0.8 m s-1). The original magma fragmentation level in the conduit was probably relatively shallow carrying mainly juvenile pyroclasts (~60 %) intermixed with accidental crustal lithics (~35 %) and mantle xenoliths (<5 %) to the surface. The shapes of individual pyroclasts are sub-rounded to rounded and with highly variable vesicularities (5-45 %). This fact, in combination with abundant fine-grained material in the beginning of the eruption, indicates that both magmatic and phreatomagmatic fragmentation processes may have played important roles in forming the FIN maar. A relatively constant increase in quartzitic fragments from ~35 to <60 % with increasing stratigraphic height in the FIN deposits further indicates that the crater area successively widened during the eruption, which resulted in an increased recycling of quartzitic fragments. This eruption scenario, with the formation of a diatreme at depth, is also consistent with the absence of layers dipping inwards into the crater area.

  10. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

    ... Swiss shores of Lake Constance at the town of Rorschach. Eutrophication, or the process of nutrient enrichment, is rapidly accelerated ... of the value of Lake Constance, efforts to mitigate eutrophication were initiated in the 1970's. MISR was built and is managed ...

  11. White Lake AOC

    EPA Pesticide Factsheets

    White Lake is in Muskegon County along the eastern shore of Lake Michigan. It was named an Area of Concern on the Great Lakes under the Great Lakes Water Quality Agreement of 1987 and delisted in 2014.

  12. Eruptive conditions and depositional processes of Narbona Pass Maar volcano, Navajo volcanic field, Navajo Nation, New Mexico (USA)

    NASA Astrophysics Data System (ADS)

    Brand, Brittany D.; Clarke, Amanda B.; Semken, Steven

    2009-01-01

    Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution of the vent, efficiency of fragmentation, and the relative importance of magmatic and external volatiles. The basal deposits form a thick (5-20 m), massive lapilli tuff to tuff-breccia deposit. This is overlain by alternating bedded sequences of symmetrical to antidune cross-stratified tuff and lapilli tuff; and diffusely-stratified, clast-supported, reversely-graded lapilli tuffs that pinch and swell laterally. This sequence is interpreted to reflect an initial vent-clearing phase that produced concentrated pyroclastic density currents, followed by a pulsating eruption that produced multiple density currents with varying particle concentrations and flow conditions to yield the well-stratified deposits. Only minor localized soft-sediment deformation was observed, no accretionary lapilli were found, and grain accretion occurs on the lee side of dunes. This suggests that little to no liquid water existed in the density currents during deposition. Juvenile material is dominantly present as blocky fine ash and finely vesiculated fine to coarse lapilli pumice. This indicates that phreatomagmatic fragmentation was predominant, but also that the magma was volatile-rich and vesiculating at the time of eruption. This is the first study to document a significant magmatic volatile component in an NVF maar-diatreme eruption. The top of the phreatomagmatic sequence abruptly contacts the overlying minette lava flows, indicating no gradual drying-out period between the explosive and effusive phases. The lithology of the accidental clasts is consistent throughout the vertical pyroclastic

  13. 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.

  14. Deglacial and postglacial evolution of the Pingualuit Crater Lake basin, northern Québec (Canada)

    NASA Astrophysics Data System (ADS)

    Desiage, Pierre-Arnaud; Lajeunesse, Patrick; St-Onge, Guillaume; Normandeau, Alexandre; Ledoux, Grégoire; Guyard, Hervé; Pienitz, Reinhard

    2015-11-01

    The Pingualuit Crater, located in the Ungava Peninsula (northern Québec, Canada) is a 1.4-Ma-old impact crater hosting a 245-m-deep lake. The lake has a great potential to preserve unique paleoclimatic and paleoecological sedimentary records of the last glacial/interglacial cycles in the terrestrial Canadian Arctic. In order to investigate the stratigraphy in the lake and the late Quaternary glacial history of the Pingualuit Crater, this study compiles data from three expeditions carried out in May 2007 ( 9-m-long sediment core), in August 2010 ( 50 km of seismic lines), and in September 2012 (high-resolution terrestrial LiDAR topography of the inner slopes). Despite the weak penetration ( 10 m) of the 3.5-kHz subbottom profiling caused by the presence of boulders in the sedimentary column, seismic data coupled with the stratigraphy established from the sediment core enabled the identification of two glaciolacustrine units deposited during the final stages of the Laurentide Ice Sheet (LIS) retreat in the crater. Two episodes of postglacial mass wasting events were also identified on the slopes and in the deep basin of the crater. The high-resolution topography of the internal slopes of the crater generated from the LiDAR data permitted the confirmation of a paleolake level at 545 m and determination of the elevation of drainage outlets. Together with the mapping of glacial and deglacial landforms from air photographs, the LiDAR data allowed the development of a new deglaciation and drainage scenario for the Pingualuit Crater Lake and surrounding area. The model proposes three main phases of lake drainage, based on the activation of seven outlets following the retreat of the LIS front toward the southwest. Finally, as opposed to other high-latitude crater lake basins such as Lake El'gygytgyn or Laguna Potrok Aike where high-resolution paleoclimatic records were obtained owing to high sediment accumulation rates, the seismic data from the Pingualuit Crater Lake

  15. Lake acidification

    SciTech Connect

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

    1987-06-01

    This paper examined a National Research Council (NRC) report called Acid Deposition: Long-Term Trends. The report has been the final word on acid deposition as the cause of acidification of lakes. The authors considered it important that the tentative nature of this report be kept in perspective so that the work of the NRC would promote rather than inhibit scientific inquiry on the lake acidification issue. In this spirit, this report proposed that degradation of storm damaged trees could increase the acidity of the forest humus and as a result the ground water which would fed local streams and lakes. They proposed that extensive forest blowdown could be a factor in acidification of surface waters.

  16. Petrochemistry of ultrapotassic tephrites and associated cognate plutonic xenoliths with carbonatite affinities from the late Quaternary Qa’le Hasan Ali maars, central Iran

    NASA Astrophysics Data System (ADS)

    Saadat, S.; Stern, C. R.; Moradian, A.

    2014-08-01

    The Quaternary Qa’le Hasan Ali (QHA) maars in central Iran occur at the intersection of the north-south Nayband fault, which defines the western boundary of the Lut micro-continental block, and a system of northwest-southeast faults, subparallel to the Zagros suture zone, that formed during the Arabian-Eurasian collision. These post-collisional maars intrude Eocene volcanic rocks of the Urumieh-Dokhtar magmatic belt, which was generated by the subduction of Neotethys oceanic lithosphere below Iran. The highly potassic, Ti-phlogopite + Mg-rich (Fo89-92) olivine + diopside-augite + aegirine-augite basanite tephrites forming the tuff rims of the QHA maars contain tephrite-coated plutonic xenoliths, some of which are interpreted as co-genetic with the tephrites based on their similar mineralogy and Sr isotopic composition (87Sr/86Sr = 0.70590). Cognate plutonic xenoliths have up to ∼20 vol% calcite, considered to be magmatic calcite because of (1) its grain size, which is similar to feldspars and aegirine-augite pyroxenes in these rocks, (2) the occurrence of fine-grained inclusions of pyroxene and apatite within these calcite grains, and (3) the similarity of the Sr-isotopic composition of this calcite with the other minerals in these rocks. The fact that the magmatic calcite has remained intact and did not volatilize during the transport of these xenoliths to the surface in the hot tephrite magma implies a short transit time, indicating that they are samples of a shallow plutonic complex, as does the presence of anorthoclase in these plutonic xenoliths. Their high modal proportion of magmatic calcite suggests that this shallow plutonic complex has affinities with carbonatites. The magmatic calcite-bearing plutonic xenoliths have high LREE/HREE ratios and contain REE-rich allanite (with up to ∼20 wt% LREE) and britholite (∼60 wt% LREE) that make up ∼3 modal percent of the most calcite-rich samples. Similar to many post-collisional highly potassic rocks

  17. Combined U/Pb and (U-Th)/He geochronometry of basalt maars in Western Carpathians: implications for age of intraplate volcanism and origin of zircon metasomatism

    NASA Astrophysics Data System (ADS)

    Hurai, Vratislav; Danišík, Martin; Huraiová, Monika; Paquette, Jean-Louis; Ádám, Alexander

    2013-10-01

    The age of intraplate volcanism in northern Pannonian Basin of Carpathians is revisited using a combination of zircon U/Pb, zircon (U-Th)/He and apatite (U-Th)/He dating techniques, complemented by electron microprobe (EMP) characterisation of dated minerals. A total of six maar structures and diatremes in the South-Slovakian Volcanic Field (SSVF) were dated and the obtained new ages yielded the following key findings: Two isolated maars in SE part indirectly dated by geomorphologic constraints to Late Pleistocene are actually of Pliocene (2.8 ± 0.2 Ma) and Late Miocene (5.5 ± 0.6 Ma) ages. In contrast, two maars in NW part of the study area are of Late Pliocene age (4.1 ± 0.4 and 5.2-5.4 Ma), younger than the Late Miocene age (~6.5 Ma) inferred previously from K/Ar data on the proximal basaltic lava flows. These maars therefore belong to the second volcanic phase that was previously identified only in SE part of the SSVF. In the light of the new geochronologic data, it seems likely that the Pliocene phreatomagmatic eruptions may have occurred along extension-related, NW- and NE-trending orthogonal faults. EMP analyses and imaging revealed an extensive syn- and post-growth metasomatic replacement by dissolution-reprecipitation in the majority of zircons. Abundant silicate melt inclusions in porous metasomatised parts of the zircons are diagnostic of magmatic rather than hydrothermal metasomatism. Consistent ages of the metasomatised and non-metasomatised zones do not indicate disturbance of the U-Pb system during the metasomatism. Enrichment in U and Th loss in the metasomatised zircons are diagnostic of an increasing oxygen fugacity triggered by degassing of the volatile residual melt during the final stages of alkali basalt fractionation. Rare zircon-to-baddeleyite transformation was probably connected with lowered silica activity in carbonated basaltic magmas in south-eastern part of the study area.

  18. Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rìo Cuarto (Costa Rica).

    PubMed

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon).

  19. Geosphere-Biosphere Interactions in Bio-Activity Volcanic Lakes: Evidences from Hule and Rìo Cuarto (Costa Rica)

    PubMed Central

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon). PMID

  20. Lake Bonneville

    USGS Publications Warehouse

    Gilbert, Grove Karl

    1890-01-01

    This volume is a contribution to the later physical history of the Great Basin. As a geographic province the Great Basin is characterized by a dry climate, changes of drainage, volcanic eruption, and crustal displacement. Lake Bonneville, the special theme of the volume, was a phenomenon of climate and drainage, but its complete history includes an account of contemporaneous eruption and displacement.

  1. The Miocene Costa Giardini diatreme, Iblean Mountains, southern Italy: model for maar-diatreme formation on a submerged carbonate platform

    NASA Astrophysics Data System (ADS)

    Calvari, Sonia; Tanner, Lawrence H.

    2011-07-01

    In this paper we present a model for the growth of a maar-diatreme complex in a shallow marine environment. The Miocene-age Costa Giardini diatreme near Sortino, in the region of the Iblei Mountains of southern Sicily, has an outer tuff ring formed by the accumulation of debris flows and surge deposits during hydromagmatic eruptions. Vesicular lava clasts, accretionary lapilli and bombs in the older ejecta indicate that initial eruptions were of gas-rich magma. Abundant xenoliths in the upper, late-deposited beds of the ring suggest rapid magma ascent, and deepening of the eruptive vent is shown by the change in slope of the country rock. The interior of the diatreme contains nonbedded breccia composed of both volcanic and country rock clasts of variable size and amount. The occurrence of bedded hyaloclastite breccia in an isolated outcrop in the middle-lower part of the diatreme suggests subaqueous effusion at a low rate following the end of explosive activity. Intrusions of nonvesicular magma, forming plugs and dikes, occur on the western side of the diatreme, and at the margins, close to the contact between breccia deposits and country rock; they indicate involvement of volatile-poor magma, possibly during late stages of activity. We propose that initial hydromagmatic explosive activity occurred in a shallow marine environment and the ejecta created a rampart that isolated for a short time the inner crater from the surrounding marine environment. This allowed explosive activity to draw down the water table in the vicinity of the vent and caused deepening of the explosive center. A subsequent decrease in the effusion rate and cessation of explosive eruptions allowed the crater to refill with water, at which time the hyaloclastite was deposited. Emplacement of dikes and plugs occurred nonexplosively while the breccia sediment was mostly still soft and unconsolidated, locally forming peperites. The sheltered, low-energy lagoon filled with marine limestones mixed

  2. Holocene climatic and hydrological changes in Big Soda Lake, Nevada

    NASA Astrophysics Data System (ADS)

    Rosen, M. R.; Reidy, L. M.; Starratt, S.; Byrne, R.

    2014-12-01

    It is important to separate the role of hydrology from climate change when assessing the Holocene history of lake sediments. Big Soda Lake is a Holocene maar lake in the Great Basin of Nevada with a 9 m sediment record that covers the Holocene. The mm-scale laminations, diatoms, and δ18O and δ13C from bulk calcite in the core are consistent with a saline, closed-basin lake down to approximately 4.3 m below the sediment water interface. The top 7 cm of the core show the influence of human hydrologic modifications to the area. Below that, stable isotope data shows variable groundwater input that is mostly consistent with climate variation from other records in the western USA. Below 4.3 m depth, the laminations abruptly end and are replaced by unlaminated massive mud, sand, and gravel to the bottom. The isotopic composition of the calcite abruptly changes from covarying, to inversely varying compositions below this break. This break occurred at about 5,600 cal yr BP. In addition, the diatom assemblage below 4.3 m is similar to that found in modern Walker Lake; whereas the diatom assemblage above 4.3 m is similar to modern Mono Lake. The δ18O isotopic composition of the calcite is on average 6 ‰ more negative below 4.3 m than above the change, indicating that the lake contained fresher water before 5,600 cal yr BP ago. The cause for the abrupt change cannot be explained through climate shifts because climate in the Great Basin has been shown to be more arid between 8,000 and 5,000 cal yr BP. It has been hypothesized that the Walker River flowed to the Carson River Basin between about 14,000 and 5,000 cal yr BP, and this added water may have raised the groundwater table sufficiently in the Carson Basin to freshen Big Soda Lake. Once the Walker River diverted back to the Walker Basin, more saline conditions prevailed reflecting changes in climate and human influence at the top of the core.

  3. The architecture, eruptive history, and evolution of the Table Rock Complex, Oregon: From a Surtseyan to an energetic maar eruption

    NASA Astrophysics Data System (ADS)

    Brand, Brittany D.; Clarke, Amanda B.

    2009-03-01

    The Table Rock Complex (TRC; Pliocene-Pleistocene), first documented and described by Heiken [Heiken, G.H., 1971. Tuff rings; examples from the Fort Rock-Christmas Lake valley basin, south-central Oregon. J. Geophy. Res. 76, 5615-5626.], is a large and well-exposed mafic phreatomagmatic complex in the Fort Rock-Christmas Lake Valley Basin, south-central Oregon. It spans an area of approximately 40 km 2, and consists of a large tuff cone in the south (TRC1), and a large tuff ring in the northeast (TRC2). At least seven additional, smaller explosion craters were formed along the flanks of the complex in the time between the two main eruptions. The first period of activity, TRC1, initiated with a Surtseyan-style eruption through a 60-70 m deep lake. The TRC1 deposits are dominated by multiple, 1-2 m thick, fining upward sequences of massive to diffusely-stratified lapilli tuff with intermittent zones of reverse grading, followed by a finely-laminated cap of fine-grained sediment. The massive deposits are interpreted as the result of eruption-fed, subaqueous turbidity current deposits; whereas, the finely laminated cap likely resulted from fallout of suspended fine-grained material through a water column. Other common features are erosive channel scour-and-fill deposits, massive tuff breccias, and abundant soft sediment deformation due to rapid sediment loading. Subaerial TRC1 deposits are exposed only proximal to the edifice, and consist of cross-stratified base-surge deposits. The eruption built a large tuff cone above the lake surface ending with an effusive stage, which produced a lava lake in the crater (365 m above the lake floor). A significant repose period occurred between the TRC1 and TRC2 eruptions, evidenced by up to 50 cm of diatomitic lake sediments at the contact between the two tuff sequences. The TRC2 eruption was the last and most energetic in the complex. General edifice morphology and a high percentage of accidental material suggest eruption through

  4. Subsurface structure of a maar-diatreme and associated tuff ring from a high-resolution geophysical survey, Rattlesnake Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Marshall, Anita; Connor, Charles; Kruse, Sarah; Malservisi, Rocco; Richardson, Jacob; Courtland, Leah; Connor, Laura; Wilson, James; Karegar, Makan A.

    2015-10-01

    Geophysical survey techniques including gravity, magnetics, and ground penetrating radar were utilized to study the diatreme and tuff ring at Rattlesnake Crater, a maar in the San Francisco Volcanic Field of northern Arizona. Significant magnetic anomalies (+ 1600 nT) and a positive gravity anomaly (+ 1.4 mGal) are associated with the maar. Joint modeling of magnetic and gravity data indicate that the diatreme that underlies Rattlesnake Crater has volume of 0.8-1 km3, and extends to at least 800 m depth. The modeled diatreme comprises at least two zones of variable density and magnetization, including a low density, highly magnetized unit near the center of the diatreme, interpreted to be a pyroclastic unit emplaced at sufficiently high temperature and containing sufficient juvenile fraction to acquire thermal remanent magnetization. Magnetic anomalies and ground penetrating radar (GPR) imaging demonstrate that the bedded pyroclastic deposits of the tuff ring also carry high magnetization, likely produced by energetic emplacement of hot pyroclastic density currents. GPR profiles on the tuff ring reveal long (~ 100 m) wavelength undulations in bedding planes. Elsewhere, comparable bedforms have been interpreted as base surge deposits inflated by air entrainment from eruption column collapse. Interpretation of these geophysical data suggests that Rattlesnake Crater produced highly energetic phreatomagmatic activity that gave way to less explosive activity as the eruption progressed. The positive gravity anomaly associated with the maar crater is interpreted to be caused by coherent bodies within the diatreme and possibly lava ponding on the crater floor. These dense magnetized bodies have excess mass of 2-4 × 1010 kg, and occupy approximately 5% of the diatreme by volume. Magnetic anomalies on the crater floor are elongate NW-SE, suggesting that the eruption may have been triggered by the interaction of ascending magma with water in fractures of this orientation

  5. Drill Core Mineral Analysis by Means of the Hyperspectral Imaging Spectrometer HySpex, XRD and Asd in Proximity of the MÝTINA Maar, Czech Republic

    NASA Astrophysics Data System (ADS)

    Koerting, F.; Rogass, C.; Kaempf, H.; Lubitz, C.; Harms, U.; Schudack, M.; Kokaly, R.; Mielke, C.; Boesche, N.; Altenberger, U.

    2015-12-01

    Imaging spectroscopy is increasingly used for surface mapping. Therefore different expert systems are being utilized to identify surface cover materials. Those expert systems mainly rely on the spectral comparison between unknown and library spectra, but their performances were only limited qualified. This study aims on the comparative analysis of drill core samples from the recently discovered maar system in the Czech Republic. Drill core samples from the surrounding area of the Mýtina maar were analyzed by X-Ray diffraction (XRD) and the hyperspectral spectrometer HySpex. Additionally, soil samples were measured in-situ by the ASD FieldSpec4 and in the laboratory by the HySpex VNIR/SWIR spectrometer system. The data was then analyzed by the MICA-algorithm and the results were compared to the results of the XRD -analysis. The XRD-analysis served here as validation basis. The results of the hyperspectral and the XRD analyses were used to densify a volcanic map that also integrates in-situ soil measurements in the surrounding area of Mýtina. The comparison of the XRD- and solaroptical remote sensing results showed a good correlation of qualified minerals if the soil organic carbon content was significantly low. Contrary to XRD, smectites and muscovites were also straightforward identified that underlines the overall performance of the approach to identify minerals. Basically, in this work an operable approach is proposed that enables the fast, repeatable and detailed analysis of drill cores, drill core samples and soil samples and, hence, provides a higher performance than state-of-the-art XRD-analyses.

  6. Late Pleistocene aeolian dust provenances and wind direction changes reconstructed by heavy mineral analysis of the sediments of the Dehner dry maar (Eifel, Germany)

    NASA Astrophysics Data System (ADS)

    Römer, Wolfgang; Lehmkuhl, Frank; Sirocko, Frank

    2016-12-01

    The study presents the results of a heavy mineral analysis from a 38 m long record of lacustrine Eifel maar sediments from a core section of the Dehner dry maar. The record encompasses the period from 29,000 to about 12,500 b2k. Statistical analyses enabled the distinction of local and regional source areas of aeolian material and revealed pronounced changes in the amounts of different heavy mineral species and corresponding changes in the grain size Index (GSI and CSI). The results indicate that during the early stages of MIS2 (39 to 30 m depth) aeolian sediments were supplied mostly from local sources. This period is characterized by low GSI and CSI ratios resulting from a reduced mobility of material due to a vegetation cover. The period between 23,000 and 12,900 b2k is characterized by a higher supply of heavy minerals from regional and more distant sources. Changes in the provenance areas are indicated in inverse relationships between zircon, rutile, tourmaline (ZRT) and carbonate particles. Shifts in the wind direction are documented in pronounced peaks of carbonate particles indicating easterly winds that have crossed the limestone basins in the Eifeler North South Zone. ZRT-group minerals on the other hand suggest a westerly source area from Palaeozoic clastic sedimentary rocks. The heavy mineral assemblage of the LGM section at 23,000 to 15,000 b2k displays a close correspondence with the stratigraphic relationships that have been obtained for the Landscape Evolution Zone 4 of the ELSA-Vegetation Stack of Sirocko et al. (2016). From the Heinrich 2 event onwards the analyses indicate an increasing degree of mixing of heavy minerals from various provinces. This suggests the existence of a presumably incomplete, thin cover of deflated loess-like sediments that has been repeatedly reworked on the elevated surfaces of the Eifel.

  7. Trace Element Geochemistry of Basaltic Tephra in Maar Cores; Implications for Centre Correlation, Field Evolution, and Mantle Source Characteristics of the Auckland Volcanic Field, New Zealand

    NASA Astrophysics Data System (ADS)

    Hopkins, J. L.; Leonard, G.; Timm, C.; Wilson, C. J. N.; Neil, H.; Millet, M. A.

    2014-12-01

    Establishing volcanic hazard and risk management strategies hinges on a detailed understanding of the type, timing and tephra dispersal of past eruptions. In order to unravel the pyroclastic eruption history of a volcanic field, genetic links between the deposits and eruption source centre need to be established. The Auckland Volcanic Field (AVF; New Zealand) has been active for ca. 200 kyr and comprises ca. 53 individual centres covering an area of ca. 360km2. These centres show a range of sizes and eruptive styles from maar craters and tuff rings, to scoria cones and lava flows consistent with both phreatomagmatic and magmatic eruptions. Superimposition of the metropolitan area of Auckland (ca. 1.4 million inhabitants) on the volcanic field makes it critically important to assess the characteristics of the volcanic activity, on which to base assessment and management of the consequent hazards. Here we present a geochemical approach for correlating tephra deposits to their source centres. To acquire the most complete stratigraphic record of pyroclastic events, maar crater cores from different locations, covering various depths and thus ages across the field were selected. Magnetic susceptibility and x-ray density scanning of the cores was used to identify the basaltic tephra horizons, which were sampled and in-situ analysis of individual shards undertaken for major and trace elements using EPMA and LA-ICP-MS techniques, respectively. Our results show that tephra shard trace element ratios are comparable and complementary to the AVF whole rock database. The use of specific trace element ratios (e.g. Gd/Yb vs. Zr/Yb) allows us to fingerprint and cross correlate tephra horizons between cores and, when coupled with newly acquired 40Ar-39Ar age dating and eruption size estimates, correlate horizons to their source centres. This integrated style of study can provide valuable information to help volcanic hazard management and forecasting, and mitigation of related risks.

  8. High-resolution paleomagnetic secular variations and relative paleointensity since the Late Pleistocene in southern South America

    NASA Astrophysics Data System (ADS)

    PASADO Science Team Lisé-Pronovost, Agathe; St-Onge, Guillaume; Gogorza, Claudia; Haberzettl, Torsten; Preda, Michel; Kliem, Pierre; Francus, Pierre; Zolitschka, Bernd

    2013-07-01

    Paleomagnetic inclination, declination and relative paleointensity were reconstructed from the sediments of Laguna Potrok Aike in the framework of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). Here we present the u-channel-based full vector paleomagnetic field reconstruction since 51.2 ka cal BP. The relative paleointensity proxy (RPI) was built by normalising the natural remanent magnetisation with the anhysteretic remanent magnetisation using the average ratio at 4 demagnetisation steps part of the ChRM interval (NRM/ARM10-40 mT). A grain size influence on the RPI was removed using a correction based on the linear relationship between the RPI and the median destructive field of the natural remanent magnetisation (MDFNRM). The new record is compared with other lacustrine and marine records and stacks from the mid- to high-latitudes of the Southern Hemisphere, revealing consistent millennial-scale variability, the identification of the Laschamp and possibly the Mono Lake geomagnetic excursions, and a direction swing possibly associated to the Hilina Pali excursion at 20 ka cal BP. Nonetheless, a global-scale comparison with other high-resolution records located on the opposite side of the Earth and with various dipole field references hint at a different behaviour of the geomagnetic field around southern South America at 46 ka cal BP.

  9. 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

  10. 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

  11. The Last Glacial Maximum in the Northern European loess belt: Correlations between loess-paleosol sequences and the Dehner Maar core (Eifel Mountains)

    NASA Astrophysics Data System (ADS)

    Zens, Joerg; Krauß, Lydia; Römer, Wolfgang; Klasen, Nicole; Pirson, Stéphane; Schulte, Philipp; Zeeden, Christian; Sirocko, Frank; Lehmkuhl, Frank

    2016-04-01

    The D1 project of the CRC 806 "Our way to Europe" focusses on Central Europe as a destination of modern human dispersal out of Africa. The paleo-environmental conditions along the migration areas are reconstructed by loess-paleosol sequences and lacustrine sediments. Stratigraphy and luminescence dating provide the chronological framework for the correlation of grain size and geochemical data to large-scale climate proxies like isotope ratios and dust content of Greenland ice cores. The reliability of correlations is improved by the development of precise age models of specific marker beds. In this study, we focus on the (terrestrial) Last Glacial Maximum of the Weichselian Upper Pleniglacial which is supposed to be dominated by high wind speeds and an increasing aridity. Especially in the Lower Rhine Embayment (LRE), this period is linked to an extensive erosion event. The disconformity is followed by an intensive cryosol formation. In order to support the stratigraphical observations from the field, luminescence dating and grain size analysis were applied on three loess-paleosol sequences along the northern European loess belt to develop a more reliable chronology and to reconstruct paleo-environmental dynamics. The loess sections were compared to newest results from heavy mineral and grain size analysis from the Dehner Maar core (Eifel Mountains) and correlated to NGRIP records. Volcanic minerals can be found in the Dehner Maar core from a visible tephra layer at 27.8 ka up to ~25 ka. They can be correlated to the Eltville Tephra found in loess section. New quartz luminescence ages from Romont (Belgium) surrounding the tephra dated the deposition between 25.0 + 2.3 ka and 25.8 + 2.4 ka. In the following, heavy minerals show an increasing importance of strong easterly winds during the second Greenland dust peak (~24 ka b2k) correlating with an extensive erosion event in the LRE. Luminescence dating on quartz bracketing the following soil formation yielded ages of

  12. 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 ...

  13. National Lakes Assessment

    EPA Pesticide Factsheets

    The National Lakes Assessment is a collaborative, statistical survey of the nation's lakes. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  14. Lake Huron LAMPs

    EPA Pesticide Factsheets

    The approach in Lake Huron differs from the Lakewide Management Plans of the other Great Lakes: no formal binational designation of lakewide beneficial use impairments, nor extensive lakewide modeling of chemical loadings

  15. 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 ...

  16. The Great Lakes

    EPA Pesticide Factsheets

    The Great Lakes form the largest surface freshwater system on Earth. The U.S. and Canada work together to restore and protect the environment in the Great Lakes Basin. Top issues include contaminated sediments, water quality and invasive species.

  17. About Lake Tahoe

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate, change, Lake Tahoe Total Maximum Daily Load TMDL), EPA-sponsored projects, list of partner agencies.

  18. 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.

  19. 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.…

  20. 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…

  1. 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…

  2. 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)

  3. Lake Effects: The Lake Superior Curriculum Guide.

    ERIC Educational Resources Information Center

    Beery, Tom; And Others

    This curriculum guide was launched in response to a need for Lake Superior-specific educational materials and contains lessons and activities that can be used to teach about Lake Superior. The lessons in this book are divided into four sections. Each of the first three sections has a background section that provides basic information about Lake…

  4. High-resolution paleomagnetic secular variations and relative paleointensity since the Late Pleistocene in southern South America

    NASA Astrophysics Data System (ADS)

    Lise-Pronovost, A.; St-Onge, G.; Gogorza, C. G.; Haberzettl, T.; Kliem, P.; Francus, P.; Zolitschka, B.

    2012-12-01

    High-resolution paleomagnetic records from the Southern Hemisphere are largely under-represented relative to the Northern Hemisphere. Here we present a high-resolution u-channel-based full vector (inclination, declination and relative paleointensity) paleomagnetic reconstruction since 51.2 ka cal BP from the maar lake Laguna Potrok Aike in Southern Patagonia (52°S, 70°W) in order to 1) document the variability of the geomagnetic field in an area of the world where observations are scarce and 2) compare this new record with other high-resolution records and stacks from around the globe in order to assess the geomagnetic field behavior in the Southern Hemisphere. The long sedimentary sequence was recovered in 2008 in the framework of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) and the radiocarbon-based chronology indicates an average sedimentation rate of 89 cm/ka for the last 51.2 ka. Detailed rock-magnetic analyses reveal that the magnetic assemblage is dominated by pseudo single domain magnetite, which is optimal for paleomagnetic reconstructions, and that the sediment fulfills the common criteria for high-quality paleomagnetic archives. The new high-resolution record from Laguna Potrok Aike is compared with the available records from the mid- to high-latitude of the Southern Hemisphere, as well as with reference records and stacks from the Northern Hemisphere, revealing consistent millennial-scale variability, the Laschamp and possibly the Mono Lake geomagnetic excursions. Interestingly, the regional and global comparisons reveal a directional swing and sharp minimum in intensity at 46 ka cal BP which appears to be mainly observed in the Southern Hemisphere and could likely be used as a new chronostratigraphic marker. In addition, a direction swing at 20 ka cal BP could be associated with the Hilina Pali excursion, recorded with details in Hawaiian lava flows. Finally, these

  5. Hazardous crater lakes studied

    NASA Astrophysics Data System (ADS)

    Kusakabe, Minoru

    Crater lakes usually sit on top of volcanic conduits and act as condensers of magmatic vapor. Studies of crater lakes can therefore provide information on both deep magmatic activity and variations in the degassing state of a shallow magmatic body. The Lake Nyos gas disaster of August 1986 and a similar event in August 1984 at Lake Monoun, both in Cameroon, resulted from the accumulation of magmatic CO2 in the bottom layers of the lakes. Geochemical monitoring of crater lakes is a promising tool for forecasting not only limnic but also volcanic eruptions. Acid-mineralized waters formed by condensation of hot magmatic volatiles in crater lakes are thought to bear some resemblance to hydrothermal fluids acting in the genesis of acid-sulfate alteration and Au-Cu-Ag mineralization of volcanic-hosted precious metal deposits.

  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. Salting our freshwater lakes.

    PubMed

    Dugan, Hilary A; Bartlett, Sarah L; Burke, Samantha M; Doubek, Jonathan P; Krivak-Tetley, Flora E; Skaff, Nicholas K; Summers, Jamie C; Farrell, Kaitlin J; McCullough, Ian M; Morales-Williams, Ana M; Roberts, Derek C; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C; Weathers, Kathleen C

    2017-04-10

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L(-1)), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.

  8. 9. GRANT LAKE AND MONO LAKE IN DISTANCE, LOOKING NORTHEAST ...

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

    9. GRANT LAKE AND MONO LAKE IN DISTANCE, LOOKING NORTHEAST - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  9. In-lake Modeling Recommendation Report for Lake Champlain TMDL

    EPA Pesticide Factsheets

    This report describes the recommended modeling approach for the in-lake modeling component of the Lake Champlain TMDL project. The report was prepared by Tetra Tech, with input from the Lake Champlain modeling workgroup. (TetraTech, 2012b)

  10. View of Lake Sabrina Dam and Lake Sabrina from east ...

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

    View of Lake Sabrina Dam and Lake Sabrina from east ridge showing spillway at photo center, view southwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  11. The enigmatic Zerelia twin-lakes (Thessaly, Central Greece): two potential meteorite impact Craters

    NASA Astrophysics Data System (ADS)

    Dietrich, V. J.; Lagios, E.; Reusser, E.; Sakkas, V.; Gartzos, E.; Kyriakopoulos, K.

    2013-09-01

    Two circular permanent lakes of 150 and 250 m diameter and 6-8 m depth to an unconsolidated muddy bottom occur 250 m apart from each other in the agricultural fields SW of the town of Almiros (Thessaly, central Greece). The age of the lakes is assumed to be Late Pliocene to Early Holocene with a minimum age of approx. 7000 yr BP. The abundant polymict, quartz-rich carbonate breccia and clasts with a clay rich matrix in the shallow embankments of the lakes show weak stratification but no volcanic structures. The carbonate clasts and particles often display spheroidal shapes and consist of calcite aggregates with feathery, arborescent, variolitic to micro-sparitic textures and spheroidal fabrics, recrystallized and deformed glass-shaped fragments, calcite globules in quartz; thus indications of possible carbonate melting, quenching and devitrification. The carbonatic matrix includes small xenomorphic phases, such as chromspinel, zircon with blurred granular and skeletal textures, skeletal rutile and ilmenite, which are interpreted as relicts of partial melting and quenching under high temperatures of 1240-1800 °C. Only a few quartz fragments exhibit indistinct planar fractures. In several cases they include exotic Al-Si- and sulfur bearing Fe-phases, < 1-10 μm as globules. The modeled "Residual Gravity" profiles through the lakes indicate negative gravity anomalies of bowl-type structures down to 150 m for the eastern lake and down to 250 m for the larger western lake. Several hypotheses can be drawn upon to explain the origin of these enigmatic twin-lakes: (a) Maar-type volcanic craters; (b) hydrothermal or CO2/hydrocarbon gas explosion craters; (c) and (d) doline holes due to karstification; or (e) small meteorite impact craters, the latter being a plausible explanation due to geologic, petrologic, and geophysical evidence. The morphology and dimensions of the lakes as well as the density contrast tomography of the bedrock favor a meteorite impact hypothesis of a

  12. Late Pleistocene aeolian dust provenances and wind direction changes reconstructed by heavy mineral analysis of the sediments of the Dehner dry maar (Eifel Mountains, Germany)

    NASA Astrophysics Data System (ADS)

    Lehmkuhl, Frank; Römer, Wolfgang; Sirocko, Frank

    2016-04-01

    The study presents the results of a heavy mineral analysis from a 38 m long record of aeolian sediments from a core section of the Dehner dry maar (Eifel Mountains, Germany). The record encompasses the period from 30 to about 12.5 ka. Heavy-mineral analysis of the silt fraction has been performed at a sampling interval of 1 m. Statistical analyses enabled the distinction of local and regional source areas of aeolian material and revealed pronounced changes in the amounts of different heavy mineral species and corresponding changes in the grain size index (GSI). The results indicate that during the early stages of MIS 2 (40 to 30m depth) aeolian sediments were supplied mostly from local sources. This period is characterized by a low GSI ratio resulting from a reduced mobility of material due to a vegetation cover. The climax of the LGM is characterized by a higher supply of heavy minerals from regional and more distant sources. Changes in the provenance areas are indicated in inverse relationships between zircon, rutile, tourmaline (ZRT) and carbonate particles. Shifts in the wind direction are documented in pronounced peaks of carbonate particles indicating easterly winds that have crossed the limestone basins in the Eifeler North South Zone. ZRT-group minerals on the other hand suggest a westerly source area and a supply from areas consisting of Paleozoic clastic sedimentary rocks. In the periods following the LGM the analyses indicate an increasing degree of mixing of heavy minerals from various provinces. This suggests the existence of a presumably incomplete, thin cover of deflatable loessic sediments that has been repeatedly reworked on the elevated surfaces of the Eifel.

  13. 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.

  14. Speciation in ancient lakes.

    PubMed

    Martens, K

    1997-05-01

    About a dozen lakes in the world are up to three orders of magnitude older than most others. Lakes Tanganyika (East Africa) and Baikal (Siberia) have probably existed in some form for 12-20 million years, maybe more. Such lakes can have different origins, sizes, shapes, depths and limnologies, but, in contrast to short-lived (mostly post-glacial) lakes, they have exceptionally high faunal diversity and levels of endemicity. A multitude of and processes accounting for these explosive radiations have recently been documented, most of them based on particular groups in certain lakes, but comparative research can detect repeated patterns. No special speciafion mechanism, exclusive to ancient lakes has been demonstrated, although cases of ultra-rapid speciation have been documented. Extant diversity results not by simple accumulation, but by a complex process of immigration, speciation and extinction.

  15. 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.

  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. 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

  19. 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.

  20. 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.

  1. 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…

  2. The lakes of Titan.

    PubMed

    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

    2007-01-04

    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 degrees 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.

  3. 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)

  4. 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…

  5. 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)…

  6. 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…

  7. Evaporation From Lake Superior

    NASA Astrophysics Data System (ADS)

    Spence, C.; Blanken, P.; Hedstrom, N.; Leshkevich, G.; Fortin, V.; Charpentier, D.; Haywood, H.

    2009-05-01

    Evaporation is a critical component of the water balance of each of the Laurentian Great Lakes, and understanding the magnitude and physical controls of evaporative water losses are important for several reasons. Recently, low water levels in Lakes Superior and Michigan/Huron have had socioeconomic, ecological, and even meteorological impacts (e.g. water quality and quantity, transportation, invasive species, recreation, etc.). The recent low water levels may be due to increased evaporation, but this is not known as operational evaporation estimates are currently calculated as the residual of water or heat budgets. Perhaps surprisingly, almost nothing is known about evaporation dynamics from Lake Superior and few direct measurements of evaporation have been made from any of the Laurentian Great Lakes. This research is the first to attempt to directly measure evaporation from Lake Superior by deploying eddy covariance instrumentation. Results of evaporation rates, their patterns and controlling mechanisms will be presented. The direct measurements of evaporation are used with concurrent satellite and climate model data to extrapolate evaporation measurements across the entire lake. This knowledge could improve predictions of how climate change may impact the lake's water budget and subsequently how the water in the lake is managed.

  8. 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.

  9. 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.

  10. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A.

    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.

  11. 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.

  12. Hindcast Wave Information for the Great Lakes. Lake Michigan

    DTIC Science & Technology

    1991-10-01

    has three major bathymetric regions, a southern, central, and northern basin. Depths over the lake are generally greater than 100 m with the...AD-A243 784 w,,v,,,,l,,,IWAVE INFORMATION STUDIES L OF US COASTLINES US AmWIS REPORT 24 HINDCAST WAVE INFORMATION FOR THE GREAT LAKES : LAKE MICHIGAN...October 1991 Final report 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Hindcast Wave Information for the Great Lakes : Lake Michigan 6. AUTHOR(S) Jon M

  13. 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.

  14. Ecology under lake ice.

    PubMed

    Hampton, Stephanie E; Galloway, Aaron W E; Powers, Stephen M; Ozersky, Ted; Woo, Kara H; Batt, Ryan D; Labou, Stephanie G; O'Reilly, Catherine M; Sharma, Sapna; Lottig, Noah R; Stanley, Emily H; North, Rebecca L; Stockwell, Jason D; Adrian, Rita; Weyhenmeyer, Gesa A; Arvola, Lauri; Baulch, Helen M; Bertani, Isabella; Bowman, Larry L; Carey, Cayelan C; Catalan, Jordi; Colom-Montero, William; Domine, Leah M; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N; Jolley, Jeff C; Kahilainen, Kimmo K; Kaup, Enn; Kehoe, Michael J; MacIntyre, Sally; Mackay, Anson W; Mariash, Heather L; McKay, Robert M; Nixdorf, Brigitte; Nõges, Peeter; Nõges, Tiina; Palmer, Michelle; Pierson, Don C; Post, David M; Pruett, Matthew J; Rautio, Milla; Read, Jordan S; Roberts, Sarah L; Rücker, Jacqueline; Sadro, Steven; Silow, Eugene A; Smith, Derek E; Sterner, Robert W; Swann, George E A; Timofeyev, Maxim A; Toro, Manuel; Twiss, Michael R; Vogt, Richard J; Watson, Susan B; Whiteford, Erika J; Xenopoulos, Marguerite A

    2017-01-01

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer 'growing seasons'. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. National Lakes Assessment Data

    EPA Pesticide Factsheets

    The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S. Environmental Protection Agency (EPA) worked with states and tribes to conduct the assessment in 2007. Data for each parameter sampled in the National Lakes Assessment (NLA) are available for downloading in a series of files as comma separated values (*.csv). Each *.csv data file has a companion text file (*.txt) that lists a dataset label and individual descriptions for each variable. Users should view the *.txt files first to help guide their understanding and use of the data.

  20. 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.

  1. 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...

  2. About Deer Lake AOC

    EPA Pesticide Factsheets

    Named an Area of Concern under the Great Lakes Water Quality Agreement of 1987, due to beneficial use impairments caused by mercury contamination: consumption restrictions, deformities or reproductive problems, eutrophication.

  3. 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

  4. Stratification of lakes

    NASA Astrophysics Data System (ADS)

    Boehrer, Bertram; Schultze, Martin

    2008-06-01

    Many lakes show vertical stratification of their water masses, at least for some extended time periods. Density differences in water bodies facilitate an evolution of chemical differences with many consequences for living organisms in lakes. Temperature and dissolved substances contribute to density differences in water. The atmosphere imposes a temperature signal on the lake surface. As a result, thermal stratification can be established during the warm season if a lake is sufficiently deep. On the contrary, during the cold period, surface cooling forces vertical circulation of water masses and removal of gradients of water properties. However, gradients of dissolved substances may be sustained for periods much longer than one annual cycle. Such lakes do not experience full overturns. Gradients may be a consequence of external inflows or groundwater seepage. In addition, photosynthesis at the lake surface and subsequent decomposition of organic material in the deeper layers of a lake can sustain a gradient of dissolved substances. Three more geochemical cycles, namely, calcite precipitation, iron cycle, and manganese cycle, are known for sustaining meromixis. A limited number of lakes do not experience a complete overturn because of pressure dependence of temperature of maximum density. Such lakes must be sufficiently deep and lie in the appropriate climate zone. Although these lakes are permanently stratified, deep waters are well ventilated, and chemical differences are small. Turbulent mixing and convective deep water renewal must be very effective. As a consequence, these lakes usually are not termed meromictic. Permanent stratification may also be created by episodic partial recharging of the deep water layer. This mechanism resembles the cycling of the ocean: horizontal gradients result from gradients at the surface, such as differential cooling or enhanced evaporation in adjacent shallow side bays. Dense water parcels can be formed which intrude the deep

  5. 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.

  6. Antarctic subglacial lake discharges

    NASA Astrophysics Data System (ADS)

    Pattyn, Frank

    Antarctic subglacial lakes were long time supposed to be relatively closed and stable environments with long residence times and slow circulations. This view has recently been challenged with evidence of active subglacial lake discharge underneath the Antarctic ice sheet. Satellite altimetry observations witnessed rapid changes in surface elevation across subglacial lakes over periods ranging from several months to more than a year, which were interpreted as subglacial lake discharge and subsequent lake filling, and which seem to be a common and widespread feature. Such discharges are comparable to jökulhlaups and can be modeled that way using the Nye-Röthlisberger theory. Considering the ice at the base of the ice sheet at pressure melting point, subglacial conduits are sustainable over periods of more than a year and over distances of several hundreds of kilometers. Coupling of an ice sheet model to a subglacial lake system demonstrated that small changes in surface slope are sufficient to start and sustain episodic subglacial drainage events on decadal time scales. Therefore, lake discharge may well be a common feature of the subglacial hydrological system, influencing the behavior of large ice sheets, especially when subglacial lakes are perched at or near the onset of large outlet glaciers and ice streams. While most of the observed discharge events are relatively small (101-102 m3 s-1), evidence for larger subglacial discharges is found in ice free areas bordering Antarctica, and witnessing subglacial floods of more than 106 m3 s-1 that occurred during the middle Miocene.

  7. Dragon Lake, Siberia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nicknamed 'Dragon Lake,' this body of water is formed by the Bratskove Reservoir, built along the Angara river in southern Siberia, near the city of Bratsk. This image was acquired in winter, when the lake is frozen. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on December 19, 1999. This is a natural color composite image made using blue, green, and red wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  8. Lake retention of manufactured nanoparticles.

    PubMed

    Koelmans, A A; Quik, J T K; Velzeboer, I

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hydraulic loadings covered the widest possible range among existing lakes. Sedimentation accounted for natural colloid as well as suspended solid settling regimes. An ENP-specific mixed sedimentation regime is proposed. This regime combines ENP sedimentation through slow settling with natural colloids from the water column, with faster settling with suspended solids from a selected part of the water column. Although sedimentation data and hydrodynamic concepts as such were not new, their first time combination or application to ENPs shows in which cases lake retention is important for these particles. In combination with ENP emission data, lake retention translates directly into potential risks of ENPs for lake benthic communities.

  9. Schistosomiasis in Lake Malawi.

    PubMed

    Cetron, M S; Chitsulo, L; Sullivan, J J; Pilcher, J; Wilson, M; Noh, J; Tsang, V C; Hightower, A W; Addiss, D G

    1996-11-09

    Schistosomiasis is a parasitic infection caused by trematodes. Humans are infected through skin contact with free-swimming cercariae which develop in freshwater snails. Schistosomiasis has been endemic to Malawi for several decades, but the open waters and shores of Lake Malawi have long been thought to be risk-free with regard to schistosomiasis transmission. However, in 1992, two US Peace Corps volunteers developed central nervous system schistosomiasis due to infection with Schistosoma haematobium following recreational water exposure at Cape Maclear on Lake Malawi. In light of these infections, a cross-sectional survey of resident expatriates and visitors to Malawi was subsequently conducted during March-April 1993 to determine the transmission potential and risk for acquiring schistosomiasis in the lake. 305 US citizens and 650 non-US foreign nationals participated in the study. Serological evidence of current or past schistosome infection was identified in 303 subjects. Indeed, seroprevalence was 32% among expatriates whose freshwater exposure was limited to Lake Malawi; S. haematobium antibodies were found in 135 of 141 seropositive specimens. The risk of seropositivity increased with the number of freshwater exposures at Lake Malawi resorts. While many resort areas in the southwestern lake region posed a significant risk, Cape Maclear was the location most strongly associated with seropositivity. Schistosome-infected Bulinus globosus, the snail vector of S. haematobium in Malawi, were found at Cape Maclear and other locations along the lakeshore.

  10. 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

  11. Red Lake and Clearwater Rivers, Red Lake County, Minnesota. Reconnaissance Report for Red Lake and Clearwater Rivers

    DTIC Science & Technology

    1991-08-01

    the -stbbasin. These are the result of efforts by the U.S. Fish and Wildlife Service (e.g., Agassiz Lake Project and Goose Lake Project), U.S. Soil...by glacial Lake Agassiz . Upper and Lower Red Lakes are remnants of this glacial lake. The topography of the subbasin ranges from 800 feet above mean...glacial Lake Agassiz and together comprise thelargest lake area wholly contained in Minnesota. The watershed drained by the Red Lake River lies within

  12. 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

  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. Glacial lake inventory and lake outburst potential in Uzbekistan.

    PubMed

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-03-16

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m(2). As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions.

  15. 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.

  16. 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.

  17. 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.

  18. A varved lake sediment record of the 10Be solar activity proxy for the Lateglacial-Holocene transition

    NASA Astrophysics Data System (ADS)

    Czymzik, Markus; Adolphi, Florian; Muscheler, Raimund; Mekhaldi, Florian; Martin-Puertas, Celia; Aldahan, Ala; Possnert, Göran; Brauer, Achim

    2016-12-01

    Solar modulated variations in cosmogenic radionuclide production provide both information on past changes in the activity of the Sun and a global synchronization tool. However, to date the use of cosmogenic radionuclides for these applications is almost exclusively based on 10Be records from ice cores and 14C time-series from tree rings, all including archive-specific limitations. We present the first 10Be record from annually laminated (varved) lake sediments for the Lateglacial-Holocene transition from Meerfelder Maar. We quantify environmental influences on the catchment and, consequently, 10Be deposition using a new approach based on regression analyses between our 10Be record and environmental proxy time-series from the same archive. Our analyses suggest that environmental influences contribute to up to 37% of the variability in our 10Be record, but cannot be the main explanation for major 10Be excursions. Corrected for these environmental influences, our 10Be record is interpreted to dominantly reflect changes in solar modulated cosmogenic radionuclide production. The preservation of a solar production signal in 10Be from varved lake sediments highlights the largely unexplored potential of these archives for solar activity reconstruction, as global synchronization tool and, thus, for more robust paleoclimate studies.

  19. 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.

  20. 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.

  1. 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

  2. Lake Sarez, Tajikistan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Lake Sarez (top), deep in the Pamir mountains of Tajikistan, was created 90 years ago when a strong earthquake triggered a massive landslide that, in turn, became a huge dam along the Murghob River, now called the Usoi Dam. The resulting lake is perched above surrounding drainages at an elevation greater than 3000m, and is part of the watershed that drains the towering Akademi Nauk Range (see the regional image, lower). The lake is 61 km long and as deep as 500 m, and holds an estimated 17 cubic km of water. The area experiences considerable seismic activity, and scientists fear that part of the right bank may slump into the lake, creating a huge wave that will top over and possibly breach the natural dam. Such a wave would create a catastrophic flood downstream along the Bartang, Panj and Amu Darya Rivers, perhaps reaching all the way to the Aral Sea. Currently, central Asian governments, as well as the World Bank and the UN are monitoring the dam closely, and have proposed gradually lowering the lake level as a preventive measure. More information about the lake is available at the following web sites: Lake Sarez Study group, UN Report, Reliefweb Digital photograph numbers ISS002-E-7771 and ISS002-E-7479 were taken in the spring of 2001 from Space Station Alpha and are provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  3. 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...

  4. Hydrogeologic Controls on Lake Level at Mountain Lake, Virginia

    NASA Astrophysics Data System (ADS)

    Roningen, J. M.; Burbey, T. J.

    2011-12-01

    Mountain Lake in Giles County, Virginia has a documented history of severe natural lake-level changes involving groundwater seepage that extend over the past 4200 years. Featured in the 1986 movie Dirty Dancing, the natural lake dried up completely in September 2008 and levels have not yet recovered. A hydrogeologic investigation was undertaken in an effort to determine the factors influencing lake level changes. A daily water balance, dipole-dipole electrical resistivity surveying, well logging and chemical sampling have shed light on: 1) the influence of a fault not previously discussed in literature regarding the lake, 2) the seasonal response to precipitation of a forested first-order drainage system in fractured rock, and 3) the possibility of flow pathways related to karst features. Geologic controls on lake level were investigated using several techniques. Geophysical surveys using dipole-dipole resistivity located possible subsurface flowpaths both to and from the lake. Well logs, lineament analysis, and joint sampling were used to assess structural controls on lake hydrology. Major ions were sampled at wells, springs, streams, and the lake to evaluate possible mixing of different sources of water in the lake. Groundwater levels were monitored for correlation to lake levels, rainfall events, and possible seismic effects. The hydrology of the lake was quantified with a water balance on a daily time step. Results from the water balance indicate steady net drainage and significant recharge when vegetation is dormant, particularly during rain-on-snow melt events. The resistivity survey reveals discrete areas that represent flow pathways from the lake, as well as flowpaths to springs upgradient of the lake located in the vicinity of the fault. The survey also suggests that some flowpaths may originate outside of the topographic watershed of the lake. Chemical evidence indicates karst may underlie the lakebed. Historical data suggest that artificial intervention

  5. 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

  6. 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...

  7. View of Lake Sabrina Dam and dry Lake Sabrina Basin ...

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

    View of Lake Sabrina Dam and dry Lake Sabrina Basin with the upstream side of the outlet structure visible at photo center, view to north-northwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  8. 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...

  9. Chemours Pompton Lakes Works Site, Pompton Lakes, NJ

    EPA Pesticide Factsheets

    E.I. DuPont De Nemours & Company is located at 2000 Cannonball Road, Pompton Lakes, New Jersey. The DuPont Pompton Lakes Works site (DuPont) occupies approximately 570 acres of land in Pompton Lakes and Wanaque.

  10. National Lakes Assessment 2007 Results

    EPA Pesticide Factsheets

    The National Lakes Assessment samples over 1,000 lakes, ponds and reservoirs across the country. Key findings from this assessment in 2007 include the biological condition and most widespread stressors of these waterbodies.

  11. 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.

  12. 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.

  13. 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,…

  14. 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.

  15. Lake-level frequency analysis for Devils Lake, North Dakota

    USGS Publications Warehouse

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

    An annual lake-volume model and a statistical water mass-balance model were used to estimate future lake-level probabilities for Devils Lake. Comparison of the models indicates upper exceedance levels of the water mass-balance model increase much more rapidly than those of the annual lake-volume model. For simulation year 5, the 99-percent exceedance is 1,417.6 feet above sea level for the annual lake-volume model and 1,423.2 feet above sea level for the water mass-balance model.

  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. Megasplash at Lake Tahoe

    NASA Astrophysics Data System (ADS)

    Moore, J. G.; Schweickert, R. A.

    2013-12-01

    Backwash from a major ~10 km3 landslide in Lake Tahoe washed away Tioga age (21 ka) moraines (Schweickert, et al 2000; Howle, 2012). Coring in the lake demonstrates a 7700-8000 yr Mt. Mazama ash is widely distributed in lake sediments that overlie the landslide blocks. Moreover, core stratigraphy and radiocarbon ages indicate that all of the sediments cored (to about 3 m depth reaching back 12 ka) were deposited after the landslide (Smith et al., 2013). The age of the landslide is hence constrained at 12-21 ka. Fifteen major subaqueous sand wave channels 2.5 to 10.2 km in length originate from subaqueous delta-terraces at depths of 5-28 m on the margins of the lake. The channels, apparently formed by turbidity currents, are distinctly erosional in their upper part, and transform to deposition aprons in their lower part as they approach the flat lake floor at 500 m depth. The channels contain wave forms (giant ripple marks) convex upstream with maximum wavelengths of 450 m. The lower depositional aprons are surfaced by sand waves convex downstream with maximum wavelengths of 100-300 m. Sand wave convexity mimics the contour of the substrate. The sand wave channel systems are mantled by the post-slide 12 ka sediments and hence have been inactive since that time. These channel-fan structures were apparently produced by backwash from the giant Tahoe landslide, which splashed ~5 km3 of water onto the surrounding countryside thereby lowering lake level by ~10 m. The sediment-charged backwash first deposited the delta-terraces at the lowered lake level and then partly eroded them to generate the sand wave channels, within minutes or hours, while seiche activity resurfaced the delta-terraces. A remarkably similar, though smaller, presently-forming system of turbidity sand wave channels has been imaged at the mouth of the Squamish River in British Columbia (Hughes Clark et al., 2012). The Tahoe splash-induced backwash was briefly equivalent to more than fifteen Squamish

  18. 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.

  19. 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.

  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. 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.

  2. 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.

  3. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

    ... mountains surrounding Salt Lake City are renowned for the dry, powdery snow that results from the arid climate and location at the ... should be used with the red filter placed over your left eye. The canyons and peaks of the Uinta and Wasatch Mountains are ...

  4. 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)

  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. 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...

  7. Poet Lake Crystal Approval

    EPA Pesticide Factsheets

    This September 19, 2016 letter from EPA approves the petition from Poet Biorefining-Lake Crystal, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the RFS

  8. Quebec: Lake Manicouagan

    Atmospheric Science Data Center

    2013-04-17

    ... kilometers in diameter and is composed of impact-brecciated rock. Glaciation and other erosional processes have reduced the extent of the ... about 5 kilometers. The lake is bounded by erosion-resistant metamorphic and igneous rocks, and shock metamorphic effects are abundant in ...

  9. 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…

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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…

  16. 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. ...

  17. 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

  18. Future volcanic lake research: revealing secrets from poorly studied lakes

    NASA Astrophysics Data System (ADS)

    Rouwet, D.; Tassi, F.; Mora-Amador, R. A.

    2012-04-01

    Volcanic lake research boosted after the 1986 Lake Nyos lethal gas burst, a limnic rather than volcanic event. This led to the formation of the IAVCEI-Commission on Volcanic Lakes, which grew out into a multi-disciplinary scientific community since the 1990's. At Lake Nyos, a degassing pipe is functional since 2001, and two additional pipes were added in 2011, aimed to prevent further limnic eruption events. There are between 150 and 200 volcanic lakes on Earth. Some acidic crater lakes topping active magmatic-hydrothermal systems are monitored continuously or discontinuously. Such detailed studies have shown their usefulness in volcanic surveillance (e.g. Ruapehu, Yugama-Kusatsu-Shiran, Poás). Others are "Nyos-type" lakes, with possible gas accumulation in bottom waters and thus potentially hazardous. "Nyos-type" lakes tend to remain stably stratified in tropical and sub-tropical climates (meromictic), leading to long-term gas build-up and thus higher potential risk. In temperate climates, such lakes tend to turn over in winter (monomictic), and thus liberating its gas charge yearly. We line out research strategies for the different types of lakes. We believe a complementary, multi-disciplinary approach (geochemistry, geophysics, limnology, biology, statistics, etc.) will lead to new insights and ideas, which can be the base for future following-up and monitoring. After 25 years of pioneering studies on rather few lakes, the scientific community should be challenged to study the many poorly studied volcanic lakes, in order to better constrain the related hazard, based on probabilistic approaches.

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. Great Lakes Demonstration 2

    DTIC Science & Technology

    2012-06-01

    Representatives from CG Districts 1, 5 , 13, and 17  Enbridge Pipeline, Co.  EPA  National Oceanic and Atmospheric Administration (NOAA)  Observers (CG...distances from the vessel‟s hull. (Figure 5 ) In that configuration, the recovery hose and hydraulic lines dragged across the surface of the nearby...No. CG-D-08-12 2. Government Accession Number 3. Recipient’s Catalog No. 4. Title and Subtitle Great Lakes Demonstration 2 Final Report 5

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Where This Occurs: Lakes and Rivers

    EPA Pesticide Factsheets

    Nutrient pollution builds up in our nation's lakes, ponds, and streams. EPA's 2010 National Lakes Assessment found that almost 20 percent of the 50,000 lakes surveyed had been impacted by nitrogen and phosphorus pollution.

  10. Gold deposition by sulfidation of ferrous Fe in the lacustrine sediments of the Pueblo Viejo district (Dominican Republic): The effect of Fe-C-S diagenesis on later hydrothermal mineralization in a Maar-Diatreme complex

    USGS Publications Warehouse

    Kettler, R.M.; Rye, R.O.; Kesler, S.E.; Meyers, P.A.; Polanco, J.; Russell, N.

    1992-01-01

    The Pueblo Viejo district, located in the Cordillera Central of the Dominican Republic, contains large Au-Ag deposits associated with acid-sulfate alteration within spilites, conglomerates and carbonaceous sedimentary rocks that were deposited in a maar-diatreme complex. Much of the Au mineralization occurs in pyritic, carbonaceous siltstones of the Pueblo Viejo Maar-Diatreme Member of the Cretaceous Los Ranchos Formation. Pyrite is the only Fe-bearing phase in mineralized rock, whereas siderite is the dominant Fe-bearing phase in siltstones distal to mineralization. Disseminated pyrite occurs as framboids, cubes, pyritohedra, concretions and cement. Early framboids occur throughout the district. Au occurs as inclusions in later non-framboid disseminated pyrite (NFDP); an occurrence that is interpreted to be indicative of contemporaneous deposition. Pyrite framboids exhibit a wide range of ??34Scdt-values (-17.5 to +4.8???) and are interpreted to have formed during biogenic reduction of pore-water sulfate. The NFDP yield restricted ??34Scdt-values ( x ?? = -5.2???, s = ??2.4???, n = 43) similar to those obtained from later vein pyrite ( x ?? = -6.4???, s = ??1.5???, n = 12). Alunite and barite have ??34S-values ranging from +18.8 to +21.6???. The interpretation that the NFDP, vein pyrite, alunite and barite, and possibly even the framboidal pyrite share a common source of igneous sulfur is supported by the ??34S data. Siderite occurs as concretions and cement, contains abundant Mg (Fe0.75Mg0.19Mn0.03Ca0.02CO3) and has ??13Cpdb- and ??18Osmow-values ranging from -2.5 to +1.1%. and +14.6 to +19.5???, respectively. These data are consistent with the interpretation that the siderite formed in lacustrine sediments and that the carbonate in the siderite is probably methanogenic, although contributions from oxidation of organic matter during biogenic sulfate reduction, thermal decarboxylation of organic matter, or magmatic vapor cannot be ruled out. Disseminated Au

  11. Progress toward lake trout restoration in Lake Michigan

    USGS Publications Warehouse

    Holey, Mark E.; Rybicki, Ronald W.; Eck, Gary W.; Brown, Edward H.; Marsden, J. Ellen; Lavis, Dennis S.; Toneys, Michael L.; Trudeau, Tom N.; Horrall, Ross M.

    1995-01-01

    Progress toward lake trout restoration in Lake Michigan is described through 1993. Extinction of the native lake trout fishery by sea lamprey predation, augmented by exploitation and habitat destruction, resulted in an extensive stocking program of hatchery-reared lake trout that began in 1965. Sea lamprey abundance was effectively controlled using selective chemical toxicants. The initial stocking produced a measurable wild year class of lake trout by 1976 in Grand Traverse Bay, but failed to continue probably due to excessive exploitation. The overall lack of successful reproduction lakewide by the late 1970s led to the development and implementation in 1985 of a focused inter-agency lakewide restoration plan by a technical committee created through the Lake Committee structure of the Great Lakes Fishery Commission. Strategies implemented in 1985 by the plan included setting a 40% total mortality goal lakewide, creating two large refuges designed to encompass historically the most productive spawning habitat and protect trout stocked over their home range, evaluating several lake trout strains, and setting stocking priorities throughout the lake. Target levels for stocking in the 1985 Plan have never been reached, and are much less than the estimated lakewide recruitment of yearlings by the native lake trout stocks. Since 1985, over 90% of the available lake trout have been stocked over the best spawning habitat, and colonization of the historically productive offshore reefs has occurred. Concentrations of spawning lake trout large enough for successful reproduction, based on observations of successful hatchery and wild stocks, have developed at specific reefs. Continued lack of recruitment at these specific sites suggests that something other than stotk abundance has limited success. Poor survival of lake trout eggs, assumed to be related to contaminant burden, occurred in the late 1970s and early 1980s, but survival has since increased to equal survival in the

  12. 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.

  13. 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

  14. 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.

  15. Grand Canyon, Lake Powell, and Lake Mead

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A snowfall in the American West provides contrast to the landscape's muted earth tones and indicates changes in topography and elevation across (clockwise from top left) Nevada, Utah, Colorado, New Mexico, Arizona, and California. In Utah, the southern ranges of the Wasatch Mountains are covered in snow, and the Colorado River etches a dark ribbon across the red rock of the Colorado Plateau. In the center of the image is the reservoir created by the Glen Canyon Dam. To the east are the gray-colored slopes of Navaho Mountain, and to the southeast, dusted with snow is the region called Black Mesa. Southwest of Glen Canyon, the Colorado enters the Grand Canyon, which cuts westward through Arizona. At a deep bend in the river, the higher elevations of the Keibab Plateau have held onto snow. At the end of the Grand Canyon lies another large reservoir, Lake Mead, which is formed by the Hoover Dam. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  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. 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.

  18. 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 ...

  19. Porewater salinity reveals past lake-level changes in Lake Van, the Earth's largest soda lake.

    PubMed

    Tomonaga, Yama; Brennwald, Matthias S; Livingstone, David M; Kwiecien, Olga; Randlett, Marie-Ève; Stockhecke, Mona; Unwin, Katie; Anselmetti, Flavio S; Beer, Jürg; Haug, Gerald H; Schubert, Carsten J; Sturm, Mike; Kipfer, Rolf

    2017-03-22

    In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about -200 m at about 30 ka BP during the last ice age.

  20. 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

  1. Lake Evaporation: a Model Study

    NASA Astrophysics Data System (ADS)

    Amayreh, Jumah Ahmad

    1995-01-01

    Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evaporation and weather data measurements were used to understand the mechanism of evaporation in the lake, determine lake-related parameters (such as roughness lengths, heat storage, net radiation, etc.), and examine and evaluate existing lake evaporation methods. This enabled the development of a modified and flexible model incorporating the tested methods for hourly and daily best estimates of lake evaporation using nearby simple land-based weather data and, if available, remotely sensed data. Average evaporation from Bear Lake was about 2 mm/day during the summer season (March-October) of this two-year (1993-1994) study. This value reflects the large amount of energy consumed in heating the water body of the lake. Moreover, evaporation from the lake was not directly related to solar radiation. This observation was clear during night time when the evaporation continued with almost the same rate as daytime evaporation. This explains the vital role of heat storage in the lake as the main driving energy for evaporation during night time and day time cloudy sky conditions. When comparing over-lake and nearby land-based weather parameters, land-based wind speed was the only weather parameter that had a significant difference of about 50% lower than over-lake measurements. Other weather parameters were quite similar. The study showed that evaporation from the lake can be accurately estimated using Penman-type equations if related parameters such as net radiation, heat storage, and

  2. 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.

  3. 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.

  4. PCB concentrations in lake trout (Salvelinus namaycush) are correlated to habitat use and lake characteristics.

    PubMed

    Guildford, S J; Muir, D C G; Houde, M; Evans, M S; Kidd, K A; Whittle, D M; Drouillard, K; Wang, X; Anderson, M R; Bronte, C R; Devault, D S; Haffner, D; Payne, J; Kling, H J

    2008-11-15

    This study considers the importance of lake trout habitat as a factor determining persistent organochlorine (OC) concentration. Lake trout is a stenothermal, cold water species and sensitive to hypoxia. Thus, factors such as lake depth, thermal stratification, and phosphorus enrichment may determine not only which lakes can support lake trout but may also influence among-lake variability in lake trout population characteristics including bioaccumulation of OCs. A survey of 23 lakes spanning much of the natural latitudinal distribution of lake trout provided a range of lake trout habitat to test the hypothesis that lake trout with greater access to littoral habitat for feeding will have lower concentrations of OCs than lake trout that are more restricted to pelagic habitat. Using the delta13C stable isotope signature in lake trout as an indicator of influence of benthic littoral feeding, we found a negative correlation between lipid-corrected delta13C and sigmaPCB concentrations supporting the hypothesis that increasing accessto littoral habitat results in lower OCs in lake trout. The prominence of mixotrophic phytoplankton in lakes with more contaminated lake trout indicated the pelagic microbial food web may exacerbate the biomagnification of OCs when lake trout are restricted to pelagic feeding. A model that predicted sigmaPCB in lake trout based on lake area and latitude (used as proximate variables for proportion of littoral versus pelagic habitat and accessibility to littoral habitat respectively) explained 73% of the variability in sigmaPCBs in lake trout in the 23 lakes surveyed.

  5. 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.

  6. 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.

  7. "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…

  8. 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.

  9. Surface seiches in Flathead Lake

    NASA Astrophysics Data System (ADS)

    Kirillin, G.; Lorang, M. S.; Lippmann, T. C.; Gotschalk, C. C.; Schimmelpfennig, S.

    2014-12-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion and bottom sediment transport and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss the lake management problems related to of the spatial seiche distribution, such as shoreline erosion, floods and transport of sediments and invasive species in Flathead Lake.

  10. Surface seiches in Flathead Lake

    NASA Astrophysics Data System (ADS)

    Kirillin, G.; Lorang, M. S.; Lippmann, T. C.; Gotschalk, C. C.; Schimmelpfennig, S.

    2015-06-01

    Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion, and bottom sediment transport, and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes, we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin to the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake, including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss lake management problems related to the spatial seiche distribution, such as shoreline erosion, floods, and transport of sediments and invasive species in Flathead Lake.

  11. 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)

  12. 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...

  13. Planktonic diatoms of Lake Ontario

    USGS Publications Warehouse

    Reinwand, Jerry F.

    1969-01-01

    The major species of diatoms in surface collections from Lake Ontario in September 1964 were Asterionella formosa, Fragilaria crotonensis, and Tabellaris fenestrata. Dominant species in the deep-water samples were Stephanodiscus astraea, S. astraea var. mintula, and F. crotonensis. The diatom flora in surface collections varied among several stations in the eastern end of the lake.

  14. Lava Lakes on Io?

    NASA Astrophysics Data System (ADS)

    Lopes, R. M. C.; Kamp, L. W.; Smythe, W. D.; Howell, R.; Mouginis-Mark, P.; Kargel, J. S.; Radebaugh, J.; Turtle, E. P.; Perry, J.; Williams, D. A.; Carlson, R. W.; Doute, S.; Galileo NIMS Team

    2003-05-01

    At least 152 active volcanic centers have been identified on Jupiter's moon Io [Lopes et al., 2003, submitted to Icarus]. Eruptions at these centers include lava flows (``Promethean" type eruptions), explosive ``Pillanian" eruptions [Keszthelyi et al., 2001, JGR 106, 33,025-52] and volcanism confined within patera walls (``Lokian", Lopes et al., 2003). Understanding the Lokian eruption mechanism is particularly important because paterae are the most ubiquitous volcanic constructs on Io's surface [Radebaugh et al. 2001, JGR, 106, 33,005-33,020] and patera volcanism is the most common eruption type on Io. We use observations from Galileo's Near-Infrared Mapping Spectrometer (NIMS) and compare them with images from Galileo's Solid State Imaging system (SSI) to map the distribution of thermal emission at several Ionian paterae. This allows us to examine how thermal emission correlates with visible features, and to investigate how thermal emission varies with time. Galileo's close fly-bys of Io from 1999 to 2001 allowed NIMS to observe the volcanoes at relatively high spatial resolution (1-30 km pixel). At these scales, observations of the several paterae reveal that the greatest thermal emission occurs at the edges. This can be explained as the crust of a lava lake breaking up against the base of the patera (caldera) walls, similar to what has been observed at lava lakes on Earth. Comparison with terrestrial analogs shows that several Ionian active paterae, such as Loki, Tupan, and Emakong, have thermal properties consistent with relatively inactive lava lakes on Earth. We discuss these results and their implications for eruption styles and resurfacing on Io. This work was supported in part by NASA's Planetary Geology and Geophysics Program.

  15. Palaeomagnetic investigations on lake sediments from NE China: a new record of geomagnetic secular variations for the last 37 ka

    NASA Astrophysics Data System (ADS)

    Frank, Ute

    2007-04-01

    Detailed palaeomagnetic investigations were carried out on two 23 m long sediment cores from Erlongwan maar lake, NE China. The sediment composition of both cores is nearly identical. Based on a macroscopical inspection of the cores 410 graded layers intercalated into the laminated sediments were identified. Measurements of the anisotropy of the magnetic susceptibility revealed that these layers have not disturbed the sediment structure in general, but only in intervals where their thicknesses exceeds 50 cm. The age model for Erlongwan is based on 15 AMS 14C-datings on bulk sediment, showing that the sediment profile spans the last 37 ka cal BP. Although one of the sediment cores has been slightly deformed during core recovery, similar inclination and declination records could be obtained by standard palaeomagnetic methods. The stacked inclination and declination records show both variations similar to those known from palaeosecular variation records from Eastern China and Japan. Therefore, the presented study is a contribution to the ongoing process of compiling a PSV mastercurve for East Asia.

  16. Ciliates and their picophytoplankton-feeding activity in a high-altitude warm-monomictic saline lake.

    PubMed

    Pestová, Dana; Macek, Miroslav; Elena Martínez Pérez, María

    2008-02-01

    The impact of feeding on autotrophic picoplankton (APP) on the ciliate composition of the assemblage was surveyed monthly along a depth gradient in the maar crater, athalassohaline, warm monomictic Lake Alchichica (Puebla, Mexico) from June 2003 to December 2005. Numbers of APP were evaluated from their autofluorescence. DAPI staining and the Fluorescently Labeled Bacteria technique were employed to count ciliates and estimate their feeding rates. A total of 38 taxa of ciliates have been identified using Quantitative Protargol Staining. Peritrichs followed by minute spirotrichs (particularly Halteria grandinella) often numerically dominated the ciliate assemblage and emerged as the most efficient APP feeders. A maximum of 54 ciliate cells ml(-1) was observed in the surface layer at the end of the mixing period, during the development of diatoms (Cyclotella alchichicana), the cyanobacterial bloom (Nodularia sp.) and its decay. Vorticellids (Pelagovorticella natans, Vorticella sp.) had the highest APP uptake (median 130 APP cil(-1) h(-1)). Mixotrophic Euplotes cf. daidaleos were important APP grazers near the oxycline. Scuticociliates (Cyclidium glaucoma, Uronema nigricans and an anaerobic cf. Isocyclidium globossum), were numerically dominant within the hypolimnetic assemblages and did not ingest APP. Generally, APP were not an important food source for the majority of the ciliate assemblage, being positively selected by a few species during the APP decay in aerobic and microaerobic conditions.

  17. 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

  18. Great Lakes Harbors Study

    DTIC Science & Technology

    1966-11-01

    Locally.assigned Library of Congress number: HE396 S25 U55 Nj 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) 1. HARBORS 2... WATER TRANSPORTATION 3. ECONOMIC ANALYSIS 4. GREAT LJAKES - 20. ABSTRACT (Continue on ie.er.se side It necesaty nd identify by blocA number) Harbor...Scope 2 DESCRIPTION AND ECONOMIC DEVELOPMENT 3 Great Lakes-St. Lawrence Navigation System 2 4 Navigation Season 3 5 Water Levels 4 6 Tributary Area 6

  19. 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.

  20. 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.

  1. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Lake Erie Reenactment; Lake Erie, Put-in-Bay, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... vicinity of Put-In-Bay, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during Battle of Lake Erie Reenactment near Put-In-Bay. This temporary safety zone is necessary...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 77 FR 39638 - Safety Zone; Barbara Harder Wedding Fireworks, Lake Erie, Lake View, NY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... No. USCG-2012-0568] RIN 1625-AA00 Safety Zone; Barbara Harder Wedding Fireworks, Lake Erie, Lake View... temporary safety zone on Lake Erie, Lake View, NY. This safety zone is intended to restrict vessels from a portion of Lake Erie during the Barbara Harder Wedding Fireworks. This temporary safety zone is...

  7. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Sixmile Lake Airports. 93.69 Section 93.69 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... 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...

  8. 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

  9. TOXAPHENE IN THE GREAT LAKES. (R825246)

    EPA Science Inventory

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  10. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...; then (3) Along the shoreline until the point where the Lake Carlos shoreline parallels an unlabeled... point at BM 1411; then (7) North from BM 1411 in a straight line to the south shoreline of Lake Miltona; then (8) Generally west along the south shoreline of Lake Miltona onto the Lake Miltona West, Minn....

  11. 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...

  12. 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.

  13. The Great Lakes' regional climate regimes

    NASA Astrophysics Data System (ADS)

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 11. GRANT LAKE AND MONO LAKE LOOKING NORTH/NORTHEAST Los ...

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

    11. GRANT LAKE AND MONO LAKE LOOKING NORTH/NORTHEAST - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  20. 10. GRANT LAKE AND MONO LAKE LOOKING EAST/NORTHEAST Los ...

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

    10. GRANT LAKE AND MONO LAKE LOOKING EAST/NORTHEAST - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  1. Physical, chemical and biological processes in Lake Vostok and other Antarctic subglacial lakes.

    PubMed

    Siegert, M J; Ellis-Evans, J C; Tranter, M; Mayer, C; Petit, J R; Salamatin, A; Priscu, J C

    2001-12-06

    Over 70 lakes have now been identified beneath the Antarctic ice sheet. Although water from none of the lakes has been sampled directly, analysis of lake ice frozen (accreted) to the underside of the ice sheet above Lake Vostok, the largest of these lakes, has allowed inferences to be made on lake water chemistry and has revealed small quantities of microbes. These findings suggest that Lake Vostok is an extreme, yet viable, environment for life. All subglacial lakes are subject to high pressure (approximately 350 atmospheres), low temperatures (about -3 degrees C) and permanent darkness. Any microbes present must therefore use chemical sources to power biological processes. Importantly, dissolved oxygen is available at least at the lake surface, from equilibration with air hydrates released from melting basal glacier ice. Microbes found in Lake Vostok's accreted ice are relatively modern, but the probability of ancient lake-floor sediments leads to a possibility of a very old biota at the base of subglacial lakes.

  2. 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.

  3. Restoration in northern Lake Gehu, a eutrophic lake in China

    NASA Astrophysics Data System (ADS)

    Wu, Xiaodong; Li, Wenchao; Pan, Jizheng; Ma, Shuzhan; Chen, Bingfa; He, Shangwei

    2017-02-01

    Lake Gehu is a severely eutrophic lake in southeast China. A series of restoration measures have been implemented since 2009 in northern Lake Gehu. This study compared aquatic plants, water quality, sediment, and phytoplankton between restoration and control areas to investigate the effect of restoration measures. The results demonstrated that aquatic macrophyte coverage increased from 0% to 10.6%; mean TP, TN, and CODMn concentrations increased by 50.0%, 42.4%, and 40.8%, respectively, compared with those before the measures were carried out; the mean Secchi depth (SD) increased to 42.5 cm, which is 1.4 times higher than that before restoration; the mean euphotic depth (Zeu) in the summer increased from 91 to 130 cm; the mean chl a concentration decreased from 34.8 to 20.2 μg/L, compared with that before restoration; the Shannon-Wiener index of phytoplankton increased by 28.7%. The mean TP and TN concentrations in sediments decreased by 63.8% and 52.4%, respectively, compared with that before dredging. These results indicate that the restoration in northern Lake Gehu was effective. To complete the transformation from an algae- to a macrophyte-stable state within the region, further measures must be adopted. This restoration of a eutrophic lake can serve as a reference for similar eutrophic lakes.

  4. Lakes and lake-like waters of the Hawaiian Archipelago

    USGS Publications Warehouse

    Maciolek, J.A.

    1982-01-01

    This summary of Hawaiian lacustrine limnology is based on 12 years of field and literature surveys of archipelagic inland waters. Lakes here are distinguished from other standing waters by limits on surface oceanic area (> 0.1 ha) and depth (> 2 m), and by the absence of flatural surface oceanic connection. A variety of extinct and existing water bodies, sometimes referred to as lakes, are noted. Six lakes are described. Five of them are in crater basins, 3 are freshwater, and 2 are elevated (highest = 3969 m). The scarcity of elevated lakes results from general permeability of the substrata. Among the 6 lakes, surface areas range from 0.22 to 88 ha and maximum depths from 3 to 248 m. Naturally occurring aquatic biota generally is low in species diversity except for phytoplankton; fishes and submersed vascular plants are absent. Two lowland lakes, freshwater Green (Wai a Pele) and saline Kauhak6, are described for the first time. Profundal Kauhak6, 248 m deep, has a surface area of only 0.35 ha, which results in an extraordinary relative depth of 370%. It is permanently stratified, a condition apparently due primarily to the unique morphometry of its basin. 

  5. 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.

  6. 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.

  7. Testing the sensitivity of stable carbon isotopes of sub-fossil Sphagnum cellulose to past climate variability: a two millennia high resolution stable carbon isotope time series from the peat deposit "Dürres Maar", Germany

    NASA Astrophysics Data System (ADS)

    Moschen, Robert; Kühl, Norbert; Peters, Sabrina; Vos, Heinz; Lücke, Andreas

    2010-05-01

    Peat deposits are terrestrial archives of environmental changes and climate dynamics over time. They are widely distributed and cover a large part of the earth's land surface often within human habitat and, thus, form an excellent basis for evaluating ecosystem and climate dynamics by multiple geochemical and biological methods. Records of the stable carbon composition of cellulose separately extracted from selected Sphagnum plant components (δ13CSphagnum) from the kettle-hole type peat deposit of 'Dürres Maar' are presented. Manually separated Sphagnum stems, branches and the small leaves covering Sphagnum branches were used for cellulose extraction and subsequent isotope measurements, because intra-plant δ13CSphagnum variability between different physical components of individual modern plants has been described (Loader et al. 2007). We observed the same isotopic offset between single plant components of sub-fossil Sphagnum plant components which is statistically highly significant and observable down-core (Moschen et al. 2009). Using the size fraction of 355-630 μm, which almost exclusively consists of single Sphagnum leaves, allows to derive environmental and climate signals based on a plant response to external controls, presumably including temperature and relative humidity. Because down-core changes in the ratio of different plant components in the peat profile seem probable, erroneous interpretations of isotope records are likely if no differentiation into single Sphagnum plant components is possible. A high resolution time series of δ13CSphagnum is presented covering the last two millennia, tracing decadal to sub-decadal past environmental and climate dynamics. The thickness of the water film surrounding the chloroplasts of Sphagnum plants has been suggested as the most important factor influencing δ13CSphagnum. This points to bog surface wetness which is primarily driven by precipitation and evaporation temperature as the major control of δ13

  8. Mid-Wisconsin to Holocene permafrost and landscape dynamics based on a drained lake basin core from the northern Seward Peninsula, northwest Alaska

    USGS Publications Warehouse

    Lenz, Josefine; Grosse, Guido; Jones, Benjamin M.; Anthony, Katey M. Walter; Bobrov, Anatoly; Wulf, Sabine; Wetterich, Sebastian

    2016-01-01

    Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a ~ 4 m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5 ka BP. The latter was terminated by the deposition of 1 m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42 ka BP. Yedoma deposition continued until 22.5 ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23 ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23 ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances.

  9. A Compilation of Gas Emission-Rate Data from Volcanoes of Cook Inlet (Spurr, Crater Peak, Redoubt, Iliamna, and Augustine) and Alaska Peninsula (Douglas, Fourpeaked, Griggs, Mageik, Martin, Peulik, Ukinrek Maars, and Veniaminof), Alaska, from 1995-2006

    USGS Publications Warehouse

    Doukas, Michael P.; McGee, Kenneth A.

    2007-01-01

    INTRODUCTION This report presents gas emission rates from data collected during numerous airborne plume-measurement flights at Alaskan volcanoes since 1995. These flights began in about 1990 as means to establish baseline values of volcanic gas emissions during periods of quiescence and to identify anomalous levels of degassing that might signal the beginning of unrest. The primary goal was to make systematic measurements at the major volcanic centers around the Cook Inlet on at least an annual basis, and more frequently during periods of unrest and eruption. A secondary goal was to measure emissions at selected volcanoes on the Alaska Peninsula. While the goals were not necessarily met in all cases due to weather, funding, or the availability of suitable aircraft, a rich dataset of quality measurements is the legacy of this continuing effort. An earlier report (Doukas, 1995) presented data for the period from 1990 through 1994 and the current report provides data through 2006. This report contains all of the available measurements for SO2, CO2, and H2S emission rates in Alaska determined by the U. S. Geological Survey from 1995 through 2006; airborne measurements for H2S began in Alaska in 2001. The results presented here are from Cook Inlet volcanoes at Spurr, Crater Peak, Redoubt, Iliamna, and Augustine and cover periods of unrest at Iliamna (1996) and Spurr (2004-2006) as well as the 2006 eruption of Augustine. Additional sporadic measurements at volcanoes on the Alaska Peninsula (Douglas, Martin, Mageik, Griggs, Veniaminof, Ukinrek Maars, Peulik, and Fourpeaked during its 2006 unrest) are also reported here.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Linking hydro-climate to the sediment archive: a combined monitoring and calibration study from a varved lake in central Turkey

    NASA Astrophysics Data System (ADS)

    Roberts, C. Neil; Dean, Jonathan R.; Eastwood, Warren J.; Jones, Matthew D.; Allcock, Samantha L.; Leng, Melanie J.; Metcalfe, Sarah E.; Woodbridge, Jessie; Yiǧitbaşıoǧlu, Hakan

    2016-04-01

    Hydro-climatic reconstructions from lake sediment proxies require an understanding of modern formation processes and calibration over multiple years. Here we use Nar Gölü, a non-outlet, monomictic maar lake in central Turkey, as a field site for such a natural experiment. Fieldwork since 1997 has included observations and measurements of lake water and sediment trap samples, and automated data logging (Jones et al., 2005; Woodbridge and Roberts, 2010; Dean et al., 2015). We compare these data to isotopic, chemical and biotic proxies preserved in the lake's annually-varved sediments. Nar Gölü underwent a 3 m lake-level fall between 2000 and 2010, and δ18O in both water and carbonates is correlated with this lake-level fall, responding to the change in water balance. Over the same period, sedimentary diatom assemblages responded via changes in habitat availability and mixing regime, while conductivity inferred from diatoms showed a rise in inferred salinity, although with a non-linear response to hydro-climatic forcing. There were also non-linear shifts in carbonate mineralogy and elemental chemistry. Building on the relationship between lake water balance and the sediment isotope record, we calibrated sedimentary δ18O against local meteorological records to derive a P/E drought index for central Anatolia. Application to of this to the longer sediment core isotope record from Nar Gölü (Jones et al. 2006) highlights major drought events over the last 600 years (Yiǧitbaşıoǧlu et al., 2015). Although this lacustrine record offers an archive of annually-dated, decadally-averaged hydro-climatic change, there were also times of non-linear lake response to climate. Robust reconstruction therefore requires understanding of physical processes as well as application of statistical correlations. Dean, J.R., Eastwood, W.J., Roberts, N., Jones, M.D., Yiǧitbaşıoǧlu, H., Allcock, S.L., Woodbridge, J., Metcalfe, S.E. and Leng, M.J. (2015) Tracking the hydro

  15. 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.

  16. Photodegradation of methylmercury in lakes

    NASA Astrophysics Data System (ADS)

    Seller, P.; Kelly, C. A.; Rudd, J. W. M.; Machutchon, A. R.

    1996-04-01

    METHYLMERCURY can accumulate in fish to concentrations that threaten human health1. Fish methylmercury concentrations are high in many reservoirs2 and acidic lakes3, and also in many remote lakes4,5-a fact that may be related to increased atmospheric deposition of anthropogenically mobilized mercury during the past few decades6. Although sources of methylmercury to lakes and reservoirs are known7, in-lake destruction has not been demonstrated to occur at the low concentrations found in most water bodies. Here we report in situ incubations of lake water that show that methylmercury is decomposed by photo- degradation in surface waters. This process is abiotic and the rate is first-order with respect to methylmercury concentration and the intensity of solar radiation. In our study lake, the calculated annual rates of methylmercury photodegradation are almost double the estimated external inputs of methylmercury from rain, snow, streamflow and land runoff, implying the existence of a large source of methylmercury from bottom sediments. Photodegradation could also be an important process in the mercury cycle of other aquatic systems. This discovery fundamentally changes our understanding of aquatic mercury cycling, and challenges the long-accepted view that microbial demethylation dominates methylmercury degradation in natural fresh waters.

  17. 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

  18. 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

  19. Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

    USGS Publications Warehouse

    Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

    2016-01-01

    Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

  20. 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.

  1. 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)

  2. 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.

  3. 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.

  4. Limnology of selected lakes in Ohio, 1975

    USGS Publications Warehouse

    Tobin, Robert L.; Youger, John D.

    1977-01-01

    Water-quality reconnaissance by the U.S. Geological Survey and Ohio Environmental Protection Agency, to evaluate the status of Ohio's lakes and reservoirs was begun in 1975 with studies of 17 lakes. Spring and summer data collections for each lake included: profile measurements of temperature, dissolved oxygen, pH, and specific conductance; field and laboratory analyses of physical, biological, chemical organic characteristics; (nutrient), and concentrations of major and minor chemical constituents from composites of the water column; and physical and chemical data from major inflows.Light penetration (secchi disk) ranged from 9.4 feet (2.9 meters) in Lake Hope to 0.4 feet (0.1 meter) in Acton Lake. Seasonal thermal stratification or stability is shown for 10 lakes deeper than 15 feet (4.6 meters). Unstable or modified temperature profiles were observed in shallow lakes (depths less than 15 feet) or lakes controlled through subsurface release valves.Dissolved oxygen saturation ranged from 229 percent (20.8 milligrams per liter) in the epilimnion of Paint Creek Lake to zero in the bottom waters of all thermally stabilized lakes. Marked chemical and physical differences and nutrient uptake and recycling developed within different thermal strata. Anaerobic zones were frequently characterized by hydrogen sulfide and ammonia.Calcium was the dominant or codominant cation, and bicarbonate and(or) sulfate were the major anions in all lakes sampled. Only Hope and Vesuvius Lakes had soft water (hardness less than 61 milligrams per liter as CaCO3 ), and both lakes were further characterized by low pH (less than 7.0). Specific conductance ranged from 510 micromhos (Deer Creek and Salt Fork Lakes) to 128 micromhos (Lake Hope). Pesticide residues were detected in Acton Lake, and concentrations of one or more trace metals were at or above Ohio Environmental Protection Agency recommended limits in 11 lakes.Fecal coliform colony counts were below 400 colonies per 100 milliliters in

  5. 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

  6. 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

  7. 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

  8. Deoxygenation of Lake Ikeda, Japan

    NASA Astrophysics Data System (ADS)

    Nagata, R.; Hasegawa, N.

    2010-12-01

    Lake Ikeda (Kagoshima prefecture, Japan) is a deep lake with a maximum depth of 233 m. Monitoring data of lake Ikeda exist since 1975. We have analyzed the long-term variability in the water conditions of Lake Ikeda. Recently, Lake Ikeda has exhibited the phenomenon of incomplete overturning because of climate warming. The concentrations of DO (dissolved oxygen) in the deepest parts of the lake have reduced. This phenomenon was observed to have started in the 1980s, and gradually, the deepest parts of the lake became anoxic. Later, the anoxic layer became thicker. Currently, winter mixing in Lake Ikeda reaches to depths of only 100 m. According to our simple estimation, the total volume of oxygen in Lake Ikeda will reduce from approximately 70% in the mid-1980s to 40% by the end of 2010. In addition to this phenomenon, the oxygen concentration appears to vary with several years oscillations. The depths to which mixing occurs depends on the severity of the winter, such as the air temperature during the winter season. The mixing period generally occurs in February; hence, the limnological year is considered to start in February. During our analysis period, the total DO mass showed high values in 1996, 2001, and 2003. Air temperature data obtained for regions near Lake Ikeda (the station name is Ibusuki) are used to clarify the cause of the high DO mass values in the three abovementioned years. During the period prior to the occurrence of the high DO mass in February 1996, i.e., in December 1995 and January 1996, the air temperature was low. Similarly, in 2001 and 2003, the air temperature was low in January (one month before the high DO mass was observed). In January 2001 and 2003, the AO (Atlantic Oscillation) index was negative. When the AO index is negative, there tends to be a greater movement of cold polar air into mid-latitudinal regions including Japan (Yamakawa, 2005). This movement induced a low air temperature in Ibusuki, and consequently, a high DO mass

  9. LAKES BENEATH THE ICE SHEET: The Occurrence, Analysis, and Future Exploration of Lake Vostok and Other Antarctic Subglacial Lakes

    NASA Astrophysics Data System (ADS)

    Siegert, Martin J.

    2005-01-01

    Airborne geophysics has been used to identify more than 100 lakes beneath the ice sheets of Antarctica. The largest, Lake Vostok, is more than 250 km in length and 1 km deep. Subglacial lakes occur because the ice base is kept warm by geothermal heating, and generated meltwater collects in topographic hollows. For lake water to be in equilibrium with the ice sheet, its roof must slope ten times more than the ice sheet surface. This slope causes differential temperatures and melting/freezing rates across the lake ceiling, which excites water circulation. The exploration of subglacial lakes has two goals: to find and understand the life that may inhabit these unique environments and to measure the climate records that occur in sediments on lake floors. The technological developments required for in situ measurements mean, however, that direct studies of subglacial lakes may take several years to happen.

  10. 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.

  11. 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.

  12. 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:...

  13. 78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ.... 165.T11-474 to read as follows: Sec. 165.T11-474 Safety Zone; Lake Havasu Triathlon; Lake Havasu...

  14. 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.

  15. 77 FR 23123 - Special Local Regulation; Smokin The Lake; Gulfport Lake; Gulfport, MS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... SECURITY Coast Guard 33 CFR Part 100 RIN 1625-AA08 Special Local Regulation; Smokin The Lake; Gulfport Lake... establishing a temporary special local regulation for a portion of Gulfport Lake in Gulfport, MS. This action... persons on navigable waters during the Smokin The Lake high speed boat races on May 5 and 6, 2012....

  16. 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...

  17. 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.

  18. 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...

  19. 78 FR 60686 - Establishment of the Big Valley District-Lake County and Kelsey Bench-Lake County Viticultural...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-02

    ... District-Lake County and Kelsey Bench-Lake County Viticultural Areas and Modification of the Red Hills Lake... the boundary of the established 31,250-acre Red Hills Lake County viticultural area in order to align... boundary based on USGS map markings. Big Valley District-Lake County and Kelsey Bench-Lake County...

  20. 75 FR 22620 - Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife Refuges...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-29

    ... Fish and Wildlife Service Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National..., Tule Lake, Bear Valley, and Clear Lake National Wildlife Refuges (Refuges) located in Klamath County..., Lower Klamath, Tule Lake, Bear Valley, and Clear Lake Refuges located in Klamath County, Oregon,...

  1. White Lake AOC Habitat Restoration Project

    EPA Pesticide Factsheets

    The Muskegon Conservation District and the White Lake Public Advisory Council in 2012 completed the White Lake AOC Shoreline Habitat Restoration Project to address the loss of shoreline and nearshore habitat.

  2. 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.

  3. What is the National Lakes Assessment?

    EPA Pesticide Factsheets

    The National Lakes Assessment is a collaborative, statistical survey of the nation's lakes. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  4. Episodic acidification of Adirondack lakes during snowmelt

    SciTech Connect

    Schaefer, D.A.; Driscoll, C.T.; Van Dreason, R.; Yatsko, C.P.

    1990-07-01

    Maximum values of acid neutralizing capacity (ANC) in Adirondack, New York lake outlets generally occur during summer and autumn. During spring snowmelt, transport of acidic water through acid-sensitive watersheds causes depression of upper lake water ANC. In some systems lake outlet ANC reaches negative values. The authors examined outlet water chemistry from II Adirondack lakes during 1986 and 1987 snowmelts. In these lakes, SO concentrations were diluted during snowmelt and did not depress ANC. For lakes with high baseline ANC values, springtime ANC depressions were primarily accompanied by basic cation dilution. For lakes with low baseline ANC, No increases dominated ANC depressions. Lakes with intermediate baseline ANC were affected by both processes and exhibited larger ANC depressions. Ammonium dilution only affected wetland systems. A model predicting a linear relationship between outlet water ANC minima and autumn ANC was inappropriate. To assess watershed response to episodic acidification, hydrologic flow paths must be considered. (Copyright (c) 1990 by the American Geophysical Union.)

  5. Lake Tahoe Water Quality Improvement Programs

    EPA Pesticide Factsheets

    Information on the Lake Tahoe watershed, EPA's protection efforts, water quality issues, effects of climate, change, Lake Tahoe Total Maximum Daily Load TMDL), EPA-sponsored projects, list of partner agencies.

  6. Clarks Hill Lake Water Quality Study.

    DTIC Science & Technology

    1982-06-01

    MACROINVERTEBRATE TAXONOMIC LIST CLARKS HILL LAKE 1981 Phylum Platyhelminthes Order Diptera Class Turbellaria Ablabesmyia parajanta unidentified Planariidae A...HILL LAKE 1981 Phylum Platyhelminthes Order Diptera (continued) Planaria sp.,’ Bezzia sp. 2 unidentified Planariidae Chaoborus punctipennis unidentified

  7. Spirit Lake Water Resource Management NPDES Permit

    EPA Pesticide Factsheets

    Under NPDES permit ND-0031101, Spirit Lake Water Resource Management is authorized to discharge to an unnamed intermittent tributary to Devils Lake which is tributary to Sheyenne River in North Dakota.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Lake Morphometry for NHD Lakes in Souris Red Rainy Region 9 HUC

    EPA Pesticide Factsheets

    Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic systems. The lake morphometry dataset included here contains estimates of Surface Area, Shoreline Length, Shoreline Development, Maximum Depth, Mean Depth, Lake Volume, Maximum Lake Length, Mean Lake Width, Maximum Lake Width, and Fetch for each of the ??lakepond?? waterbodies in the NHDPlus V2. The current release of the datasets is version 0.1 and future refinements to the data are expected.

  13. 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.

  14. Late Quaternary paleolimnology of Walker Lake, Nevada

    USGS Publications Warehouse

    Platt, Bradbury J.; Forester, R.M.; Thompson, R.S.

    1989-01-01

    Diatoms, crustaceans, and pollen from sediment cores, in conjunction with dated shoreline tufas provide evidence for lake level and environmental fluctuations of Walker Lake in the late Quaternary. Large and rapid changes of lake chemistry and level apparently resulted from variations in the course and discharge of the Walker River. Paleolimnological evidence suggests that the basin contained a relatively deep and slightly saline to freshwater lake before ca. 30 000 years B.P. During the subsequent drawdown, the Walker River apparently shifted its course and flowed northward into the Carson Sink. As a result, Walker Lake shallowed and became saline. During the full glacial, cooler climates with more effective moisture supported a shallow brine lake in the basin even without the Walker River. As glacial climates waned after 15 000 years ago, Walker Lake became a playa. The Walker River returned to its basin 4700 years ago, filling it with fresh water in a few decades. Thereafter, salinity and depth increased as evaporation concentrated inflowing water, until by 3000 years ago Walker Lake was nearly 90 m deep, according to dated shoreline tufas. Lake levels fluctuated throughout this interval in response to variations in Sierra Nevada precipitation and local evaporation. A drought in the Sierras between 2400 and 2000 years ago reduced Walker Lake to a shallow, brine lake. Climate-controlled refilling of the lake beginning 2000 years ago required about one millennium to bring Walker lake near its historic level. Through time, lake basins in the complex Lake Lahontan system, fill and desiccate in response to climatic, tectonic and geomorphic events. Detailed, multidisciplinary paleolimnologic records from related subbasins are required to separate these processes before lake level history can be reliably used to interpret paleoclimatology. ?? 1989 Kluwer Academic Publishers.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. AirMISR Lunar Lake 2000

    Atmospheric Science Data Center

    2014-04-25

    AirMISR LUNAR LAKE 2000   Project Title:  AirMISR ... Platform:  ER-2 Spatial Coverage:  Lunar Lake, Nevada (37.76, 38.73)(-116.32, -115.26) Spatial ... Order Data Readme Files:  Readme Lunar Lake 2000 Read Software Files :  IDL Code ...

  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. 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. 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 ...

  3. 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...

  4. 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.

  5. 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.

  6. Geology of central Lake Michigan.

    USGS Publications Warehouse

    Wood, R.J.; Paull, R.A.; Wolosin, C.A.; Friedel, R.J.

    1981-01-01

    The geology beneath central Lake Michigan 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 map of unconsolidated sediment (primarily Pleistocene) shows thicknesses ranging from 180 m in a steep- walled, northeast-trending valley to less than 10 m over a mid-lake topographic high. These are the dominant features developed on the gently eastward-dipping Paleozoic rocks along this part of the western flank of the Michigan basin. Two structural-stratigraphic cross sections of the study area were constructed. The cross sections, grab samples and other information were used to construct a Paleozoic geologic map. Speculations are made about the petroleum potential beneath Lake Michigan. -from Authors

  7. 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.

  8. CLEAR LAKE ROADLESS AREA, FLORIDA.

    USGS Publications Warehouse

    Patterson, Sam H.; Crandall, Thomas M.

    1984-01-01

    On the basis of a mineral survey the Clear Lake Roadless Area, Florida was concluded to offer little or no promise for the occurrence of mineral resources. The only commodity that has been mined in the area is clayey sand used in stabilizing roads and in highway construction. No peat more than a few inches thick occurs in the area. Limestone underlies all of the Clear Lake area but is under thick overburden. The region has been explored for heavy minerals and phosphate, but no resources have been found. There appears to be little promise for discovery of oil and gas in the Clear Lake area. However, the area and nearby lands have not been thoroughly tested for oil and gas, and the possibilities for discovery cannot be ruled out.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. LAKE ELEANOR ROADLESS AREA, CALIFORNIA.

    USGS Publications Warehouse

    Huber, Donald F.; Cather, Eric E.

    1984-01-01

    The Lake Eleanor Roadless Area occupies an area of about 22. 3 sq mi in the Trinity Alps of the Klamath Mountains, 14-28 mi north-northeast of Weaverville, California. Mining began in the Trinity Alps about 1850 and has continued intermittently since then. There is no record of mining activity in the Lake Eleanor Roadless Area, but placer and lode mining occurred nearby. On the basis of mineral surveys the area has little promise for the occurrence of metallic, nonmetallic, or energy resources.

  15. Chemours Pompton Lakes Works Site, Pompton Lakes, NJ

    EPA Pesticide Factsheets

    E.I. DuPont De Nemours & Company manufactured explosives on this 570-acre site at the north end of Pompton Lakes, New Jersey from 1902-1994. Land use in the vicinity is primarily residential and commercial, but also includes undeveloped areas, an interstat

  16. 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...

  17. 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.

  18. Lake level changes on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Xie, H.; Kang, S.; Ackley, S. F.

    2010-12-01

    The Tibetan Plateau (TP) in central Asia has an average elevation of more than 4000 m, covers an area of about 2.5 million km2, and is now called “the Third Pole” of the Earth with the largest ice mass outside the north and south polar regions. It is also considered as “the Water Tower” of Asia since glaciers and seasonal snow melt provide the primary water source for billions of people. The TP, as a whole, has undergone warming in the past three decades; the temperature rise of 0.3 °C per decade is twice the global warming rate. It is currently difficult, if not impossible, to monitor elevation and its change of all lakes in Tibetan Plateau (TP) using field observations. Here we use ICESat altimetry data to provide precise lake elevations and their changes during the period of 2003-2008. We find that in the 68 lakes (51 salt lakes) examined, 53 (78%) of all lakes and 44 (86%) of the salt lakes show trends of lake level increase. The mean lake level increase rate is 0.29 m/year for the 53 lakes, and 0.30 m/year for the 44 salt lakes. The largest lake level increase (0.95 m/year) we found is the lake Cedo Caka. Three of the four subregions of the TP show increased lake levels. The increase in lake level, particularly for a high percentage of salt lakes, supports the accelerated glacier melting in the TP due to global warming.

  19. Detecting Magnetosomes in Freshwater Lakes and Lake Sediments

    NASA Astrophysics Data System (ADS)

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

    2008-05-01

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

  20. 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.

  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. Salinity and hydrology of closed lakes

    USGS Publications Warehouse

    Langbein, Walter Basil

    1961-01-01

    Lakes without outlets, called closed lakes, are exclusively features of the arid and semiarid zones where annual evaporation exceeds rainfall. The number of closed lakes increases with aridity, so there are relatively few perennial closed lakes, but "dry" lakes that rarely contain water are numerous.Closed lakes fluctuate in level to a much greater degree than the open lakes of the humid zone, because variations in inflow can be compensated only by changes in surface area. Since the variability of inflow increases with aridity, it is possible to derive an approximate relationship for the coefficient of variation of lake area in terms of data on rates of evaporation, lake area, lake depth, and drainage area.The salinity of closed lakes is highly variable, ranging from less than 1 percent to over 25 percent by weight of salts. Some evidence suggests that the tonnage of salts in a lake solution is substantially less than the total input of salts into the lake over the period of existence of the closed lake. This evidence suggests further that the salts in a lake solution represent a kind of long-term balance between factors of gain and loss of salts from the solution.Possible mechanisms for the loss of salts dissolved in the lake include deposition in marginal bays, entrapment in sediments, and removal by wind. Transport of salt from the lake surface in wind spray is also a contributing, but seemingly not major, factor.The hypothesis of a long-term balance between input to and losses from the lake solution is checked by deriving a formula for the equilibrium concentration and comparing the results with the salinity data. The results indicate that the reported salinities seemingly can be explained in terms of their geometric properties and hydrologic environment.The time for accumulation of salts in the lake solution the ratio between mass of salts in the solution and the annual input may also be estimated from the geometric and hydrologic factors, in the absence of

  3. 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).

  4. Low deuterium content of Lake Vanda, Antarctica

    USGS Publications Warehouse

    Ragotzkie, R.A.; Friedman, I.

    1965-01-01

    Lake Vanda in Victoria Land, Antarctica, is permanently ice-covered and permanently stratified, with warm, salty water near the bottom. Deuterium analyses of lake water from several levels indicate that the lake has a low deuterium content, and that it is stratified with respect to this isotope. This low deuterium content supports the evidence from the lake's ionic content that the saline layer is not of marine origin, and it indicates that evaporation from the ice surface has taken place. The stratification of the lake with respect to deuterium suggests that the upper and lower layers of water were formed at different times from different sources of glacial melt water.

  5. Mercury contribution to an adirondack lake

    NASA Astrophysics Data System (ADS)

    Scrudato, R. J.; Long, D.; Weinbloom, Robert

    1987-10-01

    Elevated copper, lead, and zinc concentrations in the upper 10 to 20 cm of sediment sampled from Cranberry Lake, a large Adirondack lake, are attributed to atmospheric contributions. Pb-210 and pollen core data, however, suggest Cranberry Lake also received mercury discharges during the turn of the century when the area was the center of extensive lumbering and related activities. Elevated mercury concentrations in Cranberry Lake smallmouth bass derived from remobilization from mercury-contaminated bottom sediments which increased the bioavailability to Cranberry Lake organisms. Mercury remobilization and accumulation by fish are promoted by fluctuating pH values resulting from acid precipilation.

  6. Mercury contribution to an Adirondack lake

    SciTech Connect

    Scrudato, R.J. ); Long, D. ); Weinbloom, R. )

    1987-01-01

    Elevated copper, lead, and zinc concentrations in the upper 10 to 20 cm of sediment sampled from Cranberry Lake, a large Adirondack lake, are attributed to atmospheric contributions. Pb-210 and pollen core data, however, suggest Cranberry Lake also received mercury discharges during the turn of the century when the area was the center of extensive lumbering and related activities. Elevated mercury concentrations in Cranberry Lake smallmouth bass derived from remobilization from mercury-contaminated bottom sediments which increased the bioavailability to Cranberry Lake organisms. Mercury remobilization and accumulation by fish are promoted by fluctuating pH values resulting from acid precipitation.

  7. 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.

  8. 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

  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. 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

  11. 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

  12. "The Effect of Alternative Representations of Lake ...

    EPA Pesticide Factsheets

    Lakes can play a significant role in regional climate, modulating inland extremes in temperature and enhancing precipitation. Representing these effects becomes more important as regional climate modeling (RCM) efforts focus on simulating smaller scales. When using the Weather Research and Forecasting (WRF) model to downscale future global climate model (GCM) projections into RCM simulations, model users typically must rely on the GCM to represent temperatures at all water points. However, GCMs have insufficient resolution to adequately represent even large inland lakes, such as the Great Lakes. Some interpolation methods, such as setting lake surface temperatures (LSTs) equal to the nearest water point, can result in inland lake temperatures being set from sea surface temperatures (SSTs) that are hundreds of km away. In other cases, a single point is tasked with representing multiple large, heterogeneous lakes. Similar consequences can result from interpolating ice from GCMs to inland lake points, resulting in lakes as large as Lake Superior freezing completely in the space of a single timestep. The use of a computationally-efficient inland lake model can improve RCM simulations where the input data is too coarse to adequately represent inland lake temperatures and ice (Gula and Peltier 2012). This study examines three scenarios under which ice and LSTs can be set within the WRF model when applied as an RCM to produce 2-year simulations at 12 km gri

  13. 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.

  14. Geographic Analysis of Alaska Lake Districts

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Jones, B. M.; Zimmerman, C. E.

    2007-12-01

    The state of Alaska has over 400,000 lakes greater than 0.01 km2 in surface area covering approximately 3.3% of the landscape. As in most lake-rich regions, these lakes are unevenly distributed on the landscape. So in order to better understand how lakes are organized on the landscape and relate this geographic organization to other climatologic, geologic, and biogeographic characteristics, we analyzed the spatial distribution of Alaska lakes. Using a combination of numerical abundance and surface-area extent of lakes, we selected lake density thresholds to identify and delineate 22 lake districts in Alaska. The total area of these 22 lakes districts occupy 16% of Alaska, yet encompass 64% of lakes and 76% of lake surface-area. The three largest lake districts are associated with the Yukon-Kuskokwin Delta, the Northern Arctic Coastal Plain, and the mountain front of the Alaskan Range on the Alaska Peninsula. Interestingly, these largest lake districts are covered by >17% lakes, while most of the smaller lake districts we identified have <10% lake cover. Of the remaining smaller lake districts, 9 are associated with mountain fronts or intermountain basins, 4 are associated with coastal plains, 3 are associated with floodplains and deltas, and 3 occur in high-elevation or mountain terrain. The highest numerical lake densities occur at deltas, while relatively lower densities occur in mountainous areas where individual lakes are often larger in surface area and likely volume. Comparison of these lake districts were made to permafrost distribution, glacial history, lithology, watershed position, and regional hydrologic budgets and regimes to better understand where lake-rich regions occur, why, and how they might change in the future. Ten of the 22 lake districts occur in areas dominated by continuous permafrost, 6 occur in areas of discontinuous or sporadic permafrost, and the other 6 occur in regions without perennially frozen soils. The majority of lake districts

  15. Hydrology of Lake Carroll, Hillsborough County, Florida

    USGS Publications Warehouse

    Henderson, S.E.; Hayes, R.D.; Stoker, Y.E.

    1985-01-01

    Lakeshore property around Lake Carroll has undergone extensive residential development since 1960. This development increased the lake shoreline, altered surface water flow to and from the lake, and may have affected lake-stage characteristics. Some areas of the lake were dredged to provide fill material for lakefront property. Water-balance analyses for 1952-60, a predevelopment period, and 1961-80, a period of residential development, indicate that both net surface water flow to the lake and downward leakage from the lake to the Floridan aquifer were greater after 1960. These changes were due more to changes in the regional climate and related changes in ground-water levels than to changes associated with residential development. Results of water quality analyses in 1980-81 are within State limits for surface waters used for recreation and wildlife propagation. (USGS)

  16. 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.

  17. Snow Clouds Stream off Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Sea-viewing Wide Field-of-view Sensor (SeaWiFS) true-color image of Lake Michigan shows a lake effect where clear dry air moves eastward from Wisconsin, picking up moisture as it traverses the lake and forming dense clouds by the time it reaches Lake Michigan's eastern shore. The scene was acquired on January 17, 2002. Note the newly-fallen snow that covers Wisconsin, Michigan, and northern Illinois. The southern edge of the snow line extends to just south of the Chicago area. Chicago sits on the southwestern shore of Lake Michigan. Except for cloudy areas in the west and east and around Lake Superior, the entire Canadian portion of the broader image can be seen to be snow covered as well. Lake Winnipeg (upper left) and James Bay (upper right of center) are frozen over. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  18. 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). 

  19. 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...

  20. 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.

  1. 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…

  2. 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)

  3. CHED Events: Salt Lake City

    NASA Astrophysics Data System (ADS)

    Wink, Donald J.

    2009-03-01

    The Division of Chemical Education (CHED) Committee meetings planned for the Spring 2009 ACS Meeting in Salt Lake City will be in the Marriott City Center Hotel. Check the location of other CHED events, the CHED Social Event, the Undergraduate Program, Sci-Mix, etc. because many will be in the Salt Palace Convention Center.

  4. 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.

  5. Seiche oscillations in Lake Baikal

    NASA Astrophysics Data System (ADS)

    Smirnov, S. V.; Kucher, K. M.; Granin, N. G.; Sturova, I. V.

    2014-01-01

    The variations in the free surface of Lake Baikal at three stations (Bol'shie Koty, Listvyanka, and Baikal'sk) are measured. A modern recording method and an advanced technique of record processing are used. Based on 1-year-long observation data, the amplitudes of seiche oscillations and their seasonal changes are analyzed. It is found, in particular, that 67-min seiches are manifested in different seasons. Numerical calculations of seiches in Lake Baikal are made with the use of up-to-date bathymetric data on one-dimensional, plan, and spherical models. Spatial structures of oscillations with periods of 277, 152, 84, 67, and 59 min, corresponding to the well-expressed peaks of power spectral density, are studied. It is shown that the first four periods correspond to uninodal, binodal, trinodal, and quadrinodal longitudinal seiche modes of Lake Baikal. The periods of three solutions can correspond to the value of 59 min. The first of them is the seiche of the lake's South Basin, and two others are characterized by significant amplitude growth in the Small Sea and Chivyrkui Bay.

  6. Genetic diversity of lake whitefish in lakes Michigan and Huron: sampling, standardization, and research priorities

    USGS Publications Warehouse

    Stott, Wendylee; VanDeHey, Justin A.; Sloss, Brian L.

    2010-01-01

    We combined data from two laboratories to increase the spatial extent of a genetic data set for lake whitefish Coregonus clupeaformis from lakes Huron and Michigan and saw that genetic diversity was greatest between lakes, but that there was also structuring within lakes. Low diversity among stocks may be a reflection of relatively recent colonization of the Great Lakes, but other factors such as recent population fluctuation and localized stresses such as lamprey predation or heavy exploitation may also have a homogenizing effect. Our data suggested that there is asymmetrical movement of lake whitefish between Lake Huron and Lake Michigan; more genotypes associated with Lake Michigan were observed in Lake Huron. Adding additional collections to the calibrated set will allow further examination of diversity in other Great Lakes, answer questions regarding movement among lakes, and estimate contributions of stocks to commercial yields. As the picture of genetic diversity and population structure of lake whitefish in the Great Lakes region emerges, we need to develop methods to combine data types to help identify important areas for biodiversity and thus conservation. Adding genetic data to existing models will increase the precision of predictions of the impacts of new stresses and changes in existing pressures on an ecologically and commercially important species.

  7. Glacial Lake Lind, Wisconsin and Minnesota

    USGS Publications Warehouse

    Johnson, M.D.; Addis, K.L.; Ferber, L.R.; Hemstad, C.B.; Meyer, G.N.; Komai, L.T.

    1999-01-01

    Glacial Lake Lind developed in the pre-late Wisconsinan St. Croix River valley, Minnesota and Wisconsin, and lasted more than 1000 yr during the retreat of the Superior lobe at the end of the Wisconsinan glaciation. Lake Lind sediment consists primarily of red varved silt and clay, but also includes mud-flow deposits, nearshore silt (penecontemporaneously deformed in places), nearshore rippled sand, and deltaic sand. Lake Lind varved red clay is not part of glacial Lake Grantsburg, as suggested by earlier authors, because the red varves are separated from overlying glacial Lake Grantsburg silt and clay by a unit of deltaic and fluvial sand. Furthermore, varve correlations indicate that the base of the red varves is younger to the north, showing that the basin expanded as the Superior lobe retreated and was not a lake basin dammed to the southwest by the advancing Grantsburg sublobe. Varve correlations indicate that the Superior lobe retreated at a rate of about 200 m/yr. Uniform winter-clay thickness throughout most of the varve couplets suggests thermal stratification in the lake with clay trapped in the epilimnion; some clay would exit the lake at the outlet prior to winter freeze. Zones of thicker winter-clay layers, in places associated with mud-flow layers, indicate outlet incision, lake-level fall, and shoreline erosion and resuspension of lake clay. The most likely outlet for glacial Lake Lind was in the southwest part of the lake near the present site of Minneapolis, Minnesota. Nearshore sediment indicates that the lake level of glacial Lake Lind was around 280 m. The elevation of the base of the Lake Lind sediments indicates water depth was 20 to 55 m. Evidence in the southern part of the lake basin suggests that the Superior lobe readvanced at least once during the early stages of glacial Lake Lind. Lake Lind ended not by drainage but by being filled in by prograding deltas and outwash plains composed of sand derived from the retreating Superior lobe. It

  8. Contaminant Monitoring Strategy for Henrys Lake, Idaho

    SciTech Connect

    John S. Irving; R. P. Breckenridge

    1992-12-01

    Henrys Lake, located in southeastern Idaho, is a large, shallow lake (6,600 acres, {approx} 17.1 feet maximum depth) located at 6,472 feet elevation in Fremont Co., Idaho at the headwaters of the Henrys Fork of the Snake River. The upper watershed is comprised of high mountains of the Targhee National Forest and the lakeshore is surrounded by extensive flats and wetlands, which are mostly privately owned. The lake has been dammed since 1922, and the upper 12 feet of the lake waters are allocated for downriver use. Henrys Lake is a naturally productive lake supporting a nationally recognized ''Blue Ribbon'' trout fishery. There is concern that increasing housing development and cattle grazing may accelerate eutrophication and result in winter and early spring fish kills. There has not been a recent thorough assessment of lake water quality. However, the Department of Environmental Quality (DEQ) is currently conducting a study of water quality on Henrys Lake and tributary streams. Septic systems and lawn runoff from housing developments on the north, west, and southwest shores could potentially contribute to the nutrient enrichment of the lake. Many houses are on steep hillsides where runoff from lawns, driveways, etc. drain into wetland flats along the lake or directly into the lake. In addition, seepage from septic systems (drainfields) drain directly into the wetlands enter groundwater areas that seep into the lake. Cattle grazing along the lake margin, riparian areas, and uplands is likely accelerating erosion and nutrient enrichment. Also, cattle grazing along riparian areas likely adds to nutrient enrichment of the lake through subsurface flow and direct runoff. Stream bank and lakeshore erosion may also accelerate eutrophication by increasing the sedimentation of the lake. Approximately nine streams feed the lake (see map), but flows are often severely reduced or completely eliminated due to irrigation diversion. In addition, subsurface flows can occur as a

  9. Acoustic estimates of abundance and distribution of spawning lake trout on Sheboygan Reef in Lake Michigan

    USGS Publications Warehouse

    Warner, D.M.; Claramunt, R.M.; Janssen, J.; Jude, D.J.; Wattrus, N.

    2009-01-01

    Efforts to restore self-sustaining lake trout (Salvelinus namaycush) populations in the Laurentian Great Lakes have had widespread success in Lake Superior; but in other Great Lakes, populations of lake trout are maintained by stocking. Recruitment bottlenecks may be present at a number of stages of the reproduction process. To study eggs and fry, it is necessary to identify spawning locations, which is difficult in deep water. Acoustic sampling can be used to rapidly locate aggregations of fish (like spawning lake trout), describe their distribution, and estimate their abundance. To assess these capabilities for application to lake trout, we conducted an acoustic survey covering 22 km2 at Sheboygan Reef, a deep reef (<40 m summit) in southern Lake Michigan during fall 2005. Data collected with remotely operated vehicles (ROV) confirmed that fish were large lake trout, that lake trout were 1–2 m above bottom, and that spawning took place over specific habitat. Lake trout density exhibited a high degree of spatial structure (autocorrelation) up to a range of ~190 m, and highest lake trout and egg densities occurred over rough substrates (rubble and cobble) at the shallowest depths sampled (36–42 m). Mean lake trout density in the area surveyed (~2190 ha) was 5.8 fish/ha and the area surveyed contained an estimated 9500–16,000 large lake trout. Spatial aggregation in lake trout densities, similarity of depths and substrates at which high lake trout and egg densities occurred, and relatively low uncertainty in the lake trout density estimate indicate that acoustic sampling can be a useful complement to other sampling tools used in lake trout restoration research.

  10. Lake volume monitoring from space

    NASA Astrophysics Data System (ADS)

    Crétaux, Jean-Francois; Abarca Del Rio, Rodrigo; Berge-Nguyen, Muriel; Arsen, Adalbert; Drolon, Vanessa; Maisongrande, Philippe

    2016-04-01

    Lakes are integrator of environmental changes occurring at regional to global scale and present a high variety of behaviors on a variety of time scales (cyclic and secular) depending on the climate conditions and their morphology. In addition their crucial importance as water stocks and retaining, given the significant environment changes occurring worldwide at many anthropocentric levels, has increased the necessity of monitoring all its morphodynamics characteristics, say water level, surface (water contour) and volume. The satellite altimetry and satellite imagery together are now widely used for the calculation of lakes and reservoirs water storage changes worldwide. However strategies and algorithms to calculate these characteristics are not straightforward and need development of specific approaches. We intend to present a review of some of these methodologies by using the lakes over the Tibetan Plateau to illustrate some critical aspects and issues (technical and scientific) linked with the survey of climate changes impacts on surface waters from remote sensing data. Many authors have measured water variations using the short period of remote sensing measurements available, although time series are probably too short to lead to definitive conclusions to link these results directly with the framework of climate changes. Indeed, many processes beyond the observations are still uncertain, for example the influence of morphology of the lakes. The time response for a lake to reach new state of equilibrium is one of the key aspects often neglected in the current literature. Observations over long period of time, therein maintaining a constellation of comprehensive and complementary satellite missions with a continuity of services over decades, especially when ground gauges network is too limited is therefore a necessity. In addition, the design of future satellite missions with new instrumental concepts (e.g. SAR, SARin, Ka band altimetry, Ka interferometry) is

  11. Survival mechanisms in Antarctic lakes.

    PubMed Central

    Laybourn-Parry, Johanna

    2002-01-01

    In Antarctic lakes, organisms are confronted by continuous low temperatures as well as a poor light climate and nutrient limitation. Such extreme environments support truncated food webs with no fish, few metazoans and a dominance of microbial plankton. The key to success lies in entering the short Antarctic summer with actively growing populations. In many cases, the most successful organisms continue to function throughout the year. The few crustacean zooplankton remain active in the winter months, surviving on endogenous energy reserves and, in some cases, continuing development. Among the Protozoa, mixotrophy is an important nutritional strategy. In the extreme lakes of the McMurdo Dry Valleys, planktonic cryptophytes are forced to sustain a mixotrophic strategy and cannot survive by photosynthesis alone. The dependence on ingesting bacteria varies seasonally and with depth in the water column. In the Vestfold Hills, Pyramimonas, which dominates the plankton of some of the saline lakes, also resorts to mixotrophy, but does become entirely photosynthetic at mid-summer. Mixotrophic ciliates are also common and the entirely photosynthetic ciliate Mesodinium rubrum has a widespread distribution in the saline lakes of the Vestfold Hills, where it attains high concentrations. Bacteria continue to grow all year, showing cycles that appear to be related to the availability of dissolved organic carbon. In saline lakes, bacteria experience sub-zero temperatures for long periods of the year and have developed biochemical adaptations that include anti-freeze proteins, changes in the concentrations of polyunsaturated fatty acids in their membranes and suites of low-temperature enzymes. PMID:12171649

  12. Spatial and temporal genetic diversity of lake whitefish (Coregonus clupeaformis (Mitchill)) from Lake Huron and Lake Erie

    USGS Publications Warehouse

    Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Hartman, Travis; Johnson, Jim; Roseman, Edward F.

    2013-01-01

    Lake whitefish (Coregonus clupeaformis (Mitchill)) are important commercially, culturally, and ecologically in the Laurentian Great Lakes. Stocks of lake whitefish in the Great Lakes have recovered from low levels of abundance in the 1960s. Reductions in abundance, loss of habitat and environmental degradation can be accompanied by losses of genetic diversity and overall fitness that may persist even as populations recover demographically. Therefore, it is important to be able to identify stocks that have reduced levels of genetic diversity. In this study, we investigated patterns of genetic diversity at microsatellite DNA loci in lake whitefish collected between 1927 and 1929 (historical period) and between 1997 and 2005 (contemporary period) from Lake Huron and Lake Erie. Genetic analysis of lake whitefish from Lakes Huron and Erie shows that the amount of population structuring varies from lake to lake. Greater genetic divergences among collections from Lake Huron may be the result of sampling scale, migration patterns and demographic processes. Fluctuations in abundance of lake whitefish populations may have resulted in periods of increased genetic drift that have resulted in changes in allele frequencies over time, but periodic genetic drift was not severe enough to result in a significant loss of genetic diversity. Migration among stocks may have decreased levels of genetic differentiation while not completely obscuring stock boundaries. Recent changes in spatial boundaries to stocks, the number of stocks and life history characteristics of stocks further demonstrate the potential of coregonids for a swift and varied response to environmental change and emphasise the importance of incorporating both spatial and temporal considerations into management plans to ensure that diversity is preserved.

  13. Remote sensing of algal blooms by aircraft and satellite in Lake Erie and Utah Lake

    NASA Technical Reports Server (NTRS)

    Strong, A. E.

    1974-01-01

    During late summer, when the surface waters of Lake Erie reach their maximum temperature, an algal bloom is likely to develop. Such phenomena, which characterize eutrophic conditions, have been noticed on other shallow lakes using the Earth Resources Technology Satellite (ERTS-1). The concentration of the algae into long streamers provides additional information on surface circulations. To augment the ERTS Multispectral Scanner Subsystem data of Lake Erie, an aircraft was used to obtain correlative thermal-IR and additional multiband photographs. A large bloom of Aphanizomenon flos-aquae observed in Utah Lake together with recent bloom history in Lake Erie is used to verify the Great Lakes bloom.

  14. Life history of lake herring of Green Bay, Lake Michigan

    USGS Publications Warehouse

    Smith, Stanford H.

    1956-01-01

    Although the lake herring has been an important contributor to the commercial fish production of Green Bay, little has been known about it. This study is based on field observations and data from about 6,500 lake herring collected over the period 1948 to 1952. Relatively nonselective commercial pound nets were a primary source of material for the study of age and growth. Commercial and experimental gill nets were used to obtain data on gear selectivity and vertical distribution. Scales were employed to investigate age and growth. Age group IV normally dominated commercial catches during the first half of the calendar year and age group III the last half. At these ages the fish averaged about 10.5 inches in length. The season's growth started in May, was most rapid in July, and terminated near the end of October. The sexes grew at the same rate. Selectivity of fishing gear was found to influence the estimation of growth. Geographical and annual differences in growth are shown. Factors that might contribute to discrepancies in calculated growth are evaluated. Possible real and apparent causes of growth compensation are given. The relation between length and weight is shown to vary with sex, season, year, and method of capture. Females were relatively more plentiful in commercial catches in February than in May through December. The percentage of females decreased with increase in age in pound-net catches but increased with age in gill-net samples. Within a year class the percentage of females decreased with increase in age. Most Green Bay lake herring mature during their second or third year of life. They are pelagic spawners with most intensive spawning over shallow areas. Spawning takes place between mid-November and mid-December, and eggs hatch in April and May. Lake herring ovaries contained from 3,500 to 11,200 eggs (averaged 6,375). Progress of spawning by age, sex, and length is given. Lake herring were distributed at all depths in Green Bay in early May, were

  15. A fractal-based approach to lake size-distributions

    NASA Astrophysics Data System (ADS)

    Seekell, David A.; Pace, Michael L.; Tranvik, Lars J.; Verpoorter, Charles

    2013-02-01

    The abundance and size distribution of lakes is critical to assessing the role of lakes in regional and global biogeochemical processes. Lakes are fractal but do not always conform to the power law size-distribution typically associated with fractal geographical features. Here, we evaluate the fractal geometry of lakes with the goal of explaining apparently inconsistent observations of power law and non-power law lake size-distributions. The power law size-distribution is a special case for lakes near the mean elevation. Lakes in flat regions are power law distributed, while lakes in mountainous regions deviate from power law distributions. Empirical analyses of lake size data sets from the Adirondack Mountains in New York and the flat island of Gotland in Sweden support this finding. Our approach provides a unifying framework for lake size-distributions, indicates that small lakes cannot dominate total lake surface area, and underscores the importance of regional hypsometry in influencing lake size-distributions.

  16. 77 FR 41686 - Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-16

    ... Management, U.S. Coast Guard Sector Buffalo; telephone 716- 843-9343, email SectorBuffaloMarineSafety@uscg... Lake, OH. The Captain of the Port Buffalo has determined that fireworks launched proximate to a... Rule With the aforementioned hazards in mind, the Captain of the Port Buffalo has determined that...

  17. Patterns in benthic biodiversity link lake trophic status to structure and potential function of three large, deep lakes.

    PubMed

    Hayford, Barbara L; Caires, Andrea M; Chandra, Sudeep; Girdner, Scott F

    2015-01-01

    Relative to their scarcity, large, deep lakes support a large proportion of the world's freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world's largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe's diversity is indicative of differential response of chironomid

  18. Monitoring Land Cover Change in the Lake Superior Basin

    EPA Science Inventory

    Lake Superior is the largest freshwater lake in the world by area and the third largest by volume. It is also the most pristine of the Great Lakes (Lake Superior Lakewide Management Plan 2006). Even still, Lake Superior is not without its threats ranging from chemical contamina...

  19. Lake Michigan wetlands: classification, concerns, and management opportunities

    USGS Publications Warehouse

    Wilcox, Douglas A.; Edsall, T.; Munawar, M.

    2005-01-01

    The wetlands that border Lake Michigan are an extremely important component of the lake ecosystem. In this paper, I will review the status of wetland classifications used for Lake Michigan and the other Great Lakes, as well as the major management concerns and opportunities presented by Lake Michigan wetlands.

  20. 250 NORTH & MAIN STREET (PARK 83, SALT LAKE CITY ...

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

    250 NORTH & MAIN STREET (PARK 8-3, SALT LAKE CITY CEMETERY LOCATER), SALT LAKE CITY, UT. VIEW LOOKING NORTH - REPHOTOGRAPH OF HISTORIC SHIPLER PHOTO # 18271, UTAH STATE HISTORICAL SOCIETY COLLECTION. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  1. 40 CFR 35.1605-3 - Publicly owned freshwater lake.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Publicly owned freshwater lake. 35.1605... Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public... maintaining the public access and recreational facilities of this lake or other publicly owned...

  2. Water quality of selected lakes in Mount Rainier National Park, Washington, with respect to lake acidification

    SciTech Connect

    Turney, G.L.; Dion, N.P.; Sumioka, S.S.

    1986-01-01

    Thirteen lakes in Mount Rainier National park were evaluated for general chemical characteristics, sensitivity to acidification by acidic precipitation, and degree of existing acidification. The lakes studies were Allen, one of the Chenuis group, Crescent, Crystal, Eleanor, Fan, one of the Golfen group, Marsh, Mowich, Mystic, Shriner, and two unnamed lakes. The lakes were sampled in August 1983. The major cations were calcium and sodium, and the major anion was bicarbonate. Alkalinity concentrations ranged from 2.1 to 9.0 mg/L in 12 of the lakes. Allen Lake was the exception, having an alkalinity concentration of 27 mg/L. The pH values for all of the lakes ranged from 5.8 to 6.5. In most of the lakes, vertical profiles of temperature, dissolved oxygen, pH, and specific conductance were relatively uniform. Exceptions to general water quality patterns were observed in three lakes. Allen Lake had a specific conductance value of 58 Microsiemens/cm. The lake of the Golfen group was anaerobic at the bottom and had relatively high concentrations of dissolved organic carbon and dissolved metals, and a lower light transmission than the other lakes studied. One of the unnamed lakes had relatively high concentrations of phytoplankton and dissolved organic carbon and relatively low levels of light transmission. Comparisons of lake data to acid-sensitivity thresholds for specific conductance and alkalinity indicated that all of the lakes except Allen would be sensitive to acidic precipitation. The small sizes of the lakes, and their locations in basins of high precipitation and weathering-resistant rock types, enhance their sensitivity. None of the lakes in this study appeared to be presently acidified.

  3. Preferred temperatures of juvenile lake whitefish

    USGS Publications Warehouse

    Edsall, Thomas A.

    1999-01-01

    Lake whitefish (Coregonus clupeaformis) supported valuable commercial fisheries in all of the Great Lakes until the 1950s to 1960s when their populations collapsed due to overfishing, pollution, and predation by the exotic sea lamprey (Petromyzon marinus). Reduction of these population stresses has permitted significant recovery of the lake whitefish in the upper three Great Lakes since the 1980s, and limited but encouraging recovery is now apparent in Lakes Erie and Ontario. In the present study the thermal preferences of age-0 and age-1 lake whitefish were measured in the laboratory to provide a basis for determining thermal habitat use by juvenile lake whitefish and thermal niche overlap with exotic fishes that might prey on them. Final thermal preferenda of young lake whitefish varied inversely with fish size ranging from 16.8°C for fish averaging 1.9 g to 15.6°C for age-1 fish averaging 3.9 g. Final thermal preferenda were in agreement with the limited published information on temperature selection of juvenile lake whitefish in the laboratory and on thermal habitat use by wild, free-ranging populations in the Great Lakes.

  4. Urmia Lake (Northwest Iran): a brief review

    PubMed Central

    Eimanifar, Amin; Mohebbi, Feridon

    2007-01-01

    Lake Urmia (or Ormiyeh) is one of the largest hypersaline lakes in the world and the habitat of a unique bisexual Artemia species (A. urmiana). Despite this, and several other values of the lake, little literature on it has been published. The present paper is an attempt to provide a brief review on various aspects of the lake. Urmia Lake, located in northwestern Iran, is an oligotrophic lake of thalassohaline origin with a total surface area between 4750 and 6100 km2 and a maximum depth of 16 m at an altitude of 1250 m. The lake is divided into north and south parts separated by a causeway in which a 1500-m gap provides little exchange of water between the two parts. Due to drought and increased demands for agricultural water in the lake's basin, the salinity of the lake has risen to more than 300 g/L during recent years, and large areas of the lake bed have been desiccated. Therefore, management and conservation of this incomparable ecosystem should be considered to improve the current condition by fisheries research institutes. PMID:17506897

  5. Fat content of the flesh of siscowets and lake trout from Lake Superior

    USGS Publications Warehouse

    Eschmeyer, Paul H.; Phillips, Arthur M.

    1965-01-01

    Samples of flesh were excised from the middorsal region of 67 siscowets (Salvelinus namaycush siscowet) and 46 lake trout (Salvelinus n. namaycush) collected from Lake Superior. Chemical analysis of the samples revealed a range in fat content (dry weight) of 32.5 to 88.8 per cent in siscowets and 6.6 to 52.3 per cent in lake trout. Percentage fat increased progressively with increase in length of fish in both forms, but the average rate of increase was far greater for siscowets than for lake trout at lengths between 12 and 20 inches. Despite substantial individual variation, the percentage fat in the two forms was widely different and without overlap at all comparable lengths. The range in iodine number of the fat was 100 to 160 for siscowets and 103 to 161 for lake trout; average values were generally lower for siscowets than for lake trout among fish of comparable length. Percentage fat and relative weight were not correlated significantly in either subspecies. The fat content of flesh samples from a distinctive subpopulation of Lake Superior lake trout known as 'humpers' was more closely similar to that of typical lean lake trout than to siscowets, but the rate of increase in fat with increasing length was greater than for lean lake trout. Flesh samples from hatchery-reared stocks of lake trout, hybrid lake trout X siscowets, and siscowets tended to support the view that the wide difference in fat content between siscowets and lake trout is genetically determined.

  6. Seasonal thermal ecology of adult walleye (Sander vitreus) in Lake Huron and Lake Erie

    USGS Publications Warehouse

    Peat, Tyler B; Hayden, Todd A.; Gutowsky, Lee F G; Vandergoot, Christopher S.; Fielder, David G.; Madenjian, Charles P.; Murchie, Karen J; Dettmers, John M.; Krueger, Charles C.; Cooke, Steven J.

    2015-01-01

    The purpose of this study was to characterize thermal patterns and generate occupancy models for adult walleye from lakes Erie and Huron with internally implanted biologgers coupled with a telemetry study to assess the effects of sex, fish size, diel periods, and lake. Sex, size, and diel periods had no effect on thermal occupancy of adult walleye in either lake. Thermal occupancy differed between lakes and seasons. Walleye from Lake Erie generally experienced higher temperatures throughout the spring and summer months than did walleye in Lake Huron, due to limnological differences between the lakes. Tagged walleye that remained in Saginaw Bay, Lake Huron (i.e., adjacent to the release location), as opposed to those migrating to the main basin of Lake Huron, experienced higher temperatures, and thus accumulated more thermal units (the amount of temperature units amassed over time) throughout the year. Walleye that migrated toward the southern end of Lake Huron occupied higher temperatures than those that moved toward the north. Consequently, walleye that emigrated from Saginaw Bay experienced thermal environments that were more favorable for growth as they spent more time within their thermal optimas than those that remained in Saginaw Bay. Results presented in this paper provide information on the thermal experience of wild fish in a large lake, and could be used to refine sex- and lake-specific bioenergetics models of walleye in the Great Lakes to enable the testing of ecological hypotheses.

  7. Seasonal thermal ecology of adult walleye (Sander vitreus) in Lake Huron and Lake Erie.

    PubMed

    Peat, Tyler B; Hayden, Todd A; Gutowsky, Lee F G; Vandergoot, Christopher S; Fielder, David G; Madenjian, Charles P; Murchie, Karen J; Dettmers, John M; Krueger, Charles C; Cooke, Steven J

    2015-10-01

    The purpose of this study was to characterize thermal patterns and generate occupancy models for adult walleye from lakes Erie and Huron with internally implanted biologgers coupled with a telemetry study to assess the effects of sex, fish size, diel periods, and lake. Sex, size, and diel periods had no effect on thermal occupancy of adult walleye in either lake. Thermal occupancy differed between lakes and seasons. Walleye from Lake Erie generally experienced higher temperatures throughout the spring and summer months than did walleye in Lake Huron, due to limnological differences between the lakes. Tagged walleye that remained in Saginaw Bay, Lake Huron (i.e., adjacent to the release location), as opposed to those migrating to the main basin of Lake Huron, experienced higher temperatures, and thus accumulated more thermal units (the amount of temperature units amassed over time) throughout the year. Walleye that migrated toward the southern end of Lake Huron occupied higher temperatures than those that moved toward the north. Consequently, walleye that emigrated from Saginaw Bay experienced thermal environments that were more favorable for growth as they spent more time within their thermal optimas than those that remained in Saginaw Bay. Results presented in this paper provide information on the thermal experience of wild fish in a large lake, and could be used to refine sex- and lake-specific bioenergetics models of walleye in the Great Lakes to enable the testing of ecological hypotheses.

  8. Late Holocene lake-level fluctuations in Walker Lake, Nevada, USA

    USGS Publications Warehouse

    Yuan, F.; Linsley, B.K.; Howe, S.S.; Lund, S.P.; McGeehin, J.P.

    2006-01-01

    Walker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (??), total inorganic carbon (TIC), and oxygen isotopic composition (??18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700??years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (> 2400??years B.P.), a lake-filling period (??? 2400 to ??? 1000??years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (??? 1000 to ??? 600??years B.P.), a relatively wet period (??? 600 to ??? 100??years B.P.), and the anthropogenically induced lake-level lowering period (< 100??years B.P.). The most pronounced lowstand of Walker Lake occurred at ??? 2400??years B.P., as indicated by the relatively high values of ??18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400??years B.P. ?? 2006 Elsevier B.V. All rights reserved.

  9. Genetic structure of lake whitefish (Coregonus clupeaformis) in Lake Michigan

    USGS Publications Warehouse

    VanDeHey, J.A.; Sloss, Brian L.; Peeters, Paul J.; Sutton, T.M.

    2009-01-01

    Genetic relationships among lake whitefish (Coregonus clupeaformis) spawning aggregates in Lake Michigan were assessed and used to predict a stock or management unit (MU) model for the resource. We hypothesized that distinct spawning aggregates represented potential MUs and that differences at molecular markers underlie population differentiation. Genetic stock identification using 11 microsatellite loci indicated the presence of six genetic MUs. Resolved MUs corresponded to geographically proximate spawning aggregates clustering into genetic groups. Within MUs, analyses suggested that all but one delineated MU was a stable grouping (i.e., no between-population differences), with the exception being the Hog Island - Traverse Bay grouping. Elk Rapids was the most genetically divergent population within Lake Michigan. However, low F st values suggested that moderate to high levels of gene flow occur or have occurred in the past between MUs. Significant tests of isolation by distance and low pairwise Fst values potentially led to conflicting results between traditional analyses and a Bayesian approach. This data set could provide baseline data from which a comprehensive mixed-stock analysis could be performed, allowing for more efficient and effective management of this economically and socially important resource.

  10. Record of glacial Lake Missoula floods in glacial Lake Columbia, Washington

    NASA Astrophysics Data System (ADS)

    Hanson, Michelle A.; Clague, John J.

    2016-02-01

    During the last glaciation (marine oxygen isotope stage 2), outburst floods from glacial Lake Missoula deposited diagnostic sediments within glacial Lake Columbia. Two dominant outburst flood lithofacies are present within glacial Lake Columbia deposits: a flood expansion bar facies and a finer-grained hyperpycnite facies. We conclude that the flood sediments have a glacial Lake Missoula source because: (1) current indicators indicate westward flow through the lake, and upvalley flow followed by downvalley flow in tributary valleys; (2) no flood sediments are found north of a certain point; (3) there is a dominance of Belt-Purcell Supergroup clasts in a flood expansion bar; and (4) some of the finer-grained beds have a pink colour, reflective of glacial Lake Missoula lake-bottom sediments. A new radiocarbon age of 13,400 ± 100 14C BP on plant detritus found below 37 flood beds helps constrain the timing of outburst flooding from glacial Lake Missoula.

  11. Why study lakes? An overview of USGS lake studies in Wisconsin

    USGS Publications Warehouse

    Garn, Herbert S.; Elder, J.F.; Robertson, D.M.

    2003-01-01

    Wisconsin’s 15,000 lakes are prominent features in its landscape and an important public resource. In the northern part of the State, the recent glaciation (ending about 10,000 years ago) created one of the densest clusters of lakes found anywhere in the world, containing lakes that occupy depressions in the glacial moraines and outwash deposits (fig. 1). This Northern Lakes and Forests Ecoregion contains more than 80 percent of the State’s lakes (Wisconsin Department of Natural Resources, 2001). South of this ecoregion, there are fewer lakes, but they still are common. Usually situated in agricultural or urban land- scapes, lakes in southern Wisconsin generally have higher levels of nutrients and alkalinity, and higher biological productivity than their northern counterparts. For most lakes in Wisconsin, phosphorus is the nutrient that limits algal growth (Lillie and Mason, 1983).

  12. HYDROGEOMORPHIC PATTERNS IN COASTAL WETLANDS OF LAKE SUPERIOR: RELATIVE ROLE OF LAKE AND TRIBUTARY

    EPA Science Inventory

    Despite the documented importance of hydrodynamics in influencing the structure and fundtion of Great Lakes coastal wetlands, systematic assessments of the hydrology of coastal wetlands are lacking. This paper addresses this gap by describing patterns in lake and tributary inputs...

  13. Expanding Models of Lake Trophic State to Predict Cyanobacteria in Lakes: A Data Mining Approach

    EPA Science Inventory

    Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chloro...

  14. Expanding models of lake trophic state to predict cyanobacteria in lakes

    EPA Science Inventory

    Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chlor...

  15. Patterns of egg deposition by lake trout and lake whitefish at Tawas artificial Reef, Lake Huron, 1990-1993

    USGS Publications Warehouse

    Foster, N.R.; Kennedy, G.W.; Munawar, M.; Edsall, T.; Leach, J.

    1995-01-01

    In August 1987, the Michigan Department of Natural Resources (MDNR), with the help and co-sponsorship of Walleyes for Iosco County, constructed Tawas artificial reef to improve recreational fishing in Tawas Bay. Post-construction assessment in October, 1987, by the MDNR found twice as many adult lake trout in a gill net set on the reef as in a similar net set off the reef, indicating that lake trout already had begun to investigate this new habitat. Similar netting efforts in October 1989 caught three times as many adults on the reef as off it, even though the on-reef net was set for less than one third as long a period. Using a remotely operated vehicle (ROV), we detected prespawning aggregations of lake trout on the reef in fall 1989, and MDNR biologists set emergent fly traps on the reef in April-May 1990-1991. These fry traps captured several newly emerged lake trout and lake whitefish fry, demonstrating that eggs of both species has hatched successfully. Gill netting in 1992-1993 by U.S. Fish and Wildlife Service biologists netted large numbers of ripe lake trout in late October and ripe lake whitefish in early to mid-November. The purpose of this paper is to describe the relative quantities of eggs deposited and the spatial patterns of egg deposition by lake trout and lake whitefish at Tawas artificial reef during 1990-1993.

  16. Lake trout spawning habitat in the Six Fathom Bank-Yankee Reef lake trout sanctuary, Lake Huron

    USGS Publications Warehouse

    Edsall, Thomas A.; Brown, Charles L.; Kennedy, Gregory W.; Poe, Thomas P.

    1992-01-01

    Attempts to reestablish self-sustaining stocks of lake trout (Salvelinus namaycush) in the lower four Great Lakes, where the species was extinguished in the 1950s and 1960s, have been largely unsuccessful. To avoid many of the problems believed to be contributing to this failure, the fishery management community recently established several sanctuaries in the offshore waters of the Great Lakes where the development and protection of self-sustaining stocks of lake trout would be a primary management objective. One of these, the Six Fathom Bank-Yankee Reef sanctuary, was created in the south-central portion of Lake Huron. This sanctuary covers 168,000 ha and includes the shallower portions of the Six Fathom and Ipperwash scarps, which are major bathymetric features in the southern half of the lake. Historical accounts describe Six Fathom Bank as the most important lake trout spawning ground in the lake. Here we present the results of lake bed surveys conducted in the sanctuary with side-scan sonar, underwater videocamera systems, and a small research submarine. Our observations of the lake bed are consistent with what is known of the bedrock stratigraphy, glacial history, and karst geomorphology of the Lake Huron basin. Most of the loose rock we found seemed to be derived from local carbonate bedrock formations, although non-carbonate rock probably from Precambrian sources to the north was also present in some areas. Much of the bedrock and loose rock displayed karst solution features described for the Bruce Peninsula on the Ontario shoreline. Our surveys revealed substantial areas of lake bed at water depths of 20–36 m that resembled suitable spawning and fry production habitat for the shallow-water strains of lake trout that are the focus of the rehabilitation effort. Low mid-lake nutrient levels documented recently by others and the extremely high abundance of Mysis relicta (an important item in the diet of young lake trout) that we documented on Yankee Reef

  17. Sedimentary constraints on late Quaternary lake-level fluctuations at Bear Lake, Utah and Idaho

    USGS Publications Warehouse

    Smoot, J.P.; Rosenbaum, J.G.

    2009-01-01

    A variety of sedimentological evidence was used to construct the lake-level history for Bear Lake, Utah and Idaho, for the past ???25,000 years. Shorelines provide evidence of precise lake levels, but they are infrequently preserved and are poorly dated. For cored sediment similar to that in the modern lake, grain-size distributions provide estimates of past lake depths. Sedimentary textures provide a highly sensitive, continuous record of lake-level changes, but the modern distribution of fabrics is poorly constrained, and many ancient features have no modern analog. Combining the three types of data yields a more robust lake-level history than can be obtained from any one type alone. When smooth age-depth models are used, lake-level curves from multiple cores contain inconsistent intervals (i.e., one record indicates a rising lake level while another record indicates a falling lake level). These discrepancies were removed and the multiple records were combined into a single lake-level curve by developing age-depth relations that contain changes in deposition rate (i.e., gaps) where indicated by sedimentological evidence. The resultant curve shows that, prior to 18 ka, lake level was stable near the modern level, probably because the lake was overflowing. Between ca. 17.5 and 15.5 ka, lake level was ???40 m below the modern level, then fluctuated rapidly throughout the post-glacial interval. Following a brief rise centered ca. 15 ka ( = Raspberry Square phase), lake level lowered again to 15-20 m below modern from ca. 14.8-11.8 ka. This regression culminated in a lowstand to 40 m below modern ca. 12.5 ka, before a rapid rise to levels above modern ca. 11.5 ka. Lake level was typically lower than present throughout the Holocene, with pronounced lowstands 15-20 m below the modern level ca. 10-9, 7.0, 6.5-4.5, 3.5, 3.0-2.5, 2.0, and 1.5 ka. High lake levels near or above the modern lake occurred ca. 8.5-8.0, 7.0-6.5, 4.5-3.5, 2.5, and 0.7 ka. This lake-level history

  18. Thermal springs in Lake Baikal

    USGS Publications Warehouse

    Shanks, Wayne C.; Callender, E.

    1992-01-01

    The ??18O values of pore wqters range from -15.2??? to -16.7???, and ??D values range from -119??? to -126??? (both isotopes determined relative to standard mean ocean water [SMOW]). Bottom water in Lake Baikal has a ??18O value of -5.6??? and a ??D value of -120???. Pore waters in the vent area are significantly enriched in Mg, K, Ca, and especially Na and have the lowest ??D and ??18O values; these pore waters are isotopically and chemically distinct from pore waters in other, more typical parts of the lake. The pore-water isotopic data fall on a local meteoric water line, and covariations in water isotopes and chemistry are not consistent with evaporation or hydrothermal water-rock interaction. The thermal springs represent discharging meteoric waters that have been gently heated during subsurface circulation and are largely unaltered isotopically. Chemical variations are most likely due to dissolution of subsurface evaporites. -from Authors

  19. Chemical characteristics of Adirondack lakes

    SciTech Connect

    Driscoll, C.T.; Newton, R.M.

    1985-11-01

    This paper discussed the role of atmospheric deposition of mineral acids in the acidification of low-ionic-strength (dilute) surface waters in remote regions. Surface water acidification has been attributed to the atmospheric deposition of sulfuric acid, sulfur dioxide, and nitric acid, the oxidation of organic nitrogen from the soil, the production of soluble organic acids through the decay of dead plants and animals in soil, the oxidation of naturally occurring sulfide minerals, and the changes in land use. The research reported here was conducted as part of the Regionalized Integrated Lake-Watershed Acidification Study (RILWAS). The intent was to evaluate the general chemical characteristics of lakes in the Adirondack region of New York and to access the mechanisms that regulate the acid-base chemistry of these waters. 36 references, 5 figures, 3 tables.

  20. Radionuclides in Mono Lake, California

    SciTech Connect

    Simpson, H.J.; Trier, R.M.; Toggweiler, J.R.; Mathieu, G.; Deck, B.L.; Olsen, C.R.; Hammond, D.E.; Fuller, C.; Ku, T.L.

    1982-04-30

    Several radioisotopes of the naturally occurring uranium and thorium decay series, in addition to fallout plutonium, have unusually high concentrations in the water column of Mono Lake, a natural alkaline, saline lake. Complexing by carbonate ions appears to be responsible for the enhanced solubility of actinide elements with oxidation states of IV to VI. In contrast, fallout strontium-90 has been largely removed from the water, probably as a result of coprecipitation with calcium carbonate. The daughter/parent activity ratios of thorium, radium, and uranium isotopes suggest that thorium is removed from the water column to the sediments on time scales substantially longer than a month and that the desorption of thorium from the sediments to the water column requires less than a few years.

  1. Radionuclides in Mono Lake, California

    SciTech Connect

    Simpson, H.J.; Trier, R.M.; Toggweiler, J.R.; Mathieu, G.; Deck, B.L.; Olsen, C.R.; Hammond, D.E.; Fuller, C.; Ku, T.L.

    1982-04-01

    Several radioisotopes of the naturally occurring uranium and thorium decay series, in addition to fallout plutonium have unusually high concentrations in the water column of Mono Lake, a natural alkaline, saline lake. Complexing by carbonate ions appears to be responsible for the enhanced solubility of actinide elements with oxidation states of IV to VI. In contrast, fallout strontium-90 has been largely removed from the water, probably as a result of coprecipitation with calcium carbonate. The daughter/parent activity ratios of thorium, radium, and uranium isotopes suggest that thorium is removed from the water column to the sediments on time scales substantially longer than a month and that the desorption of thorium from the sediments to the water column requires less than a few years. 2 tables.

  2. A blood chemistry profile for lake trout

    USGS Publications Warehouse

    Edsall, Carol Cotant

    1999-01-01

    A blood chemistry profile for lake trout Salvelinus namaycush was developed by establishing baseline ranges for several clinical chemistry tests (glucose, total protein, amylase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, calcium, and magnesium). Measurements were made accurately and rapidly with a Kodak Ektachem DT60 Analyzer and the Ektachem DTSC Module. Blood serum was collected from both laboratory-reared lake trout (1978 and 1986 year-classes) and feral spawning trout from Lake Michigan and then analyzed in the laboratory. No clinically significant differences were found between samples analyzed fresh and those frozen for 1 or 6 weeks. The ranges in chemistry variables for feral lake trout were generally wider than those for laboratory-reared lake trout, and significant differences existed between male and female feral lake trout for several tests. Blood chemistry profiles also varied seasonally on fish sampled repeatedly.

  3. Dry Climate Disconnected the Laurentian Great Lakes

    NASA Astrophysics Data System (ADS)

    Lewis, C. F. Michael; King, John W.; Blasco, Stefan M.; Brooks, Gregory R.; Coakley, John P.; Croley, Thomas E.; Dettman, David L.; Edwards, Thomas W. D.; Heil, Clifford W.; Hubeny, J. Bradford; Laird, Kathleen R.; McAndrews, John H.; McCarthy, Francine M. G.; Medioli, Barbara E.; Moore, Theodore C.; Rea, David K.; Smith, Alison J.

    2008-12-01

    Recent studies have produced a new understanding of the hydrological history of North America's Great Lakes, showing that water levels fell several meters below lake basin outlets during an early postglacial dry climate in the Holocene (younger than 10,000 radiocarbon years, or about 11,500 calibrated or calendar years before present (B.P.)). Water levels in the Huron basin, for example, fell more than 20 meters below the basin overflow outlet between about 7900 and 7500 radiocarbon (about 8770-8290 calibrated) years B.P. Outlet rivers, including the Niagara River, presently falling 99 meters from Lake Erie to Lake Ontario (and hence Niagara Falls), ran dry. This newly recognized phase of low lake levels in a dry climate provides a case study for evaluating the sensitivity of the Great Lakes to current and future climate change.

  4. Top consumer abundance influences lake methane efflux.

    PubMed

    Devlin, Shawn P; Saarenheimo, Jatta; Syväranta, Jari; Jones, Roger I

    2015-11-04

    Lakes are important habitats for biogeochemical cycling of carbon. The organization and structure of aquatic communities influences the biogeochemical interactions between lakes and the atmosphere. Understanding how trophic structure regulates ecosystem functions and influences greenhouse gas efflux from lakes is critical to understanding global carbon cycling and climate change. With a whole-lake experiment in which a previously fishless lake was divided into two treatment basins where fish abundance was manipulated, we show how a trophic cascade from fish to microbes affects methane efflux to the atmosphere. Here, fish exert high grazing pressure and remove nearly all zooplankton. This reduction in zooplankton density increases the abundance of methanotrophic bacteria, which in turn reduce CH4 efflux rates by roughly 10 times. Given that globally there are millions of lakes emitting methane, an important greenhouse gas, our findings that aquatic trophic interactions significantly influence the biogeochemical cycle of methane has important implications.

  5. Orthophosphate turnover in East African lakes.

    PubMed

    Peters, Robert Henry; MacIntyre, Sally

    1976-12-01

    Turnover rates of (32)P-PO4 and concentrations of orthophosphate as soluble reactive phosphorus (SRP) were measured in five East African waters. Rapid incorporation of (32)P-PO4 by the seston and orthophosphate concentrations below the limit of detectibility were found in Lakes Elmenteita, Naivasha, and Naivasha Crater Lake. Turnover was slow and orthophosphate concentration high in both Lake Nakuru and the Crescent Island Crater basin of Lake Naivasha. Further experiments in Lake Nakuru indicated that colloidal binding of orthophosphate was limited and that particles retained by an 8.0 μ filter incorporated 66% as much tracer as particles retained by a 0.1 μ filter. These experiments strengthen our conclusion that a large quantity of orthophosphate is available for algal use in Lake Nakuru.

  6. Assessment of lake trout spawning habitat quality in central Lake Huron by submarine

    USGS Publications Warehouse

    Manny, Bruce A.; Edsall, Thomas A.

    1989-01-01

    Interstitial water quality was measured using a submersible at seven locations on Six Fathom Bank. Historically, the bank was an important lake trout spawning ground. It is currently the focus of coordinated, interagency efforts to rehabilitate lake trout in Lake Huron. Water quality, evaluated from measurements of biochemical oxygen demand, dissolved oxygen, ammonia, and hydrogen sulfide among the rocks, would not prevent lake trout eggs from hatching successfully on the bank.

  7. Ontogenic and spatial patterns in diet and growth of lake trout in Lake Michigan

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.

    1998-01-01

    Lake trout Salvelinus namaycush in nearshore waters of Lake Michigan grow faster than lake trout residing offshore on Sheboygan Reef, which is in midlake. We examined the stomachs of lake trout, spanning ages 1 through 16, caught in both nearshore and offshore environments of Lake Michigan during 1994 and 1995 to determine whether diet differences may be responsible for the difference in growth rate. A comparison of the diets, coupled with bioenergetics modeling, indicated that juvenile lake trout on Sheboygan Reef experienced slow growth due to low food availability rather than to cold water temperatures. The availability of appropriate-size prey appeared to regulate lake trout growth. Small prey fish were probably not readily available to small (200- to 399-mm total length) lake trout on Sheboygan Reef, a substantial portion of whose diet consisted of invertebrates; in contrast, nearshore juveniles had a nearly 100% fish diet. Growth rate on the reef remained slow through intermediate lake trout sizes (400-599 mm total length), presumably due to low availability of rainbow smelt Osmerus mordax on the reef. Once lake trout achieved total lengths of approximately 600 mm, they grew slightly faster on Sheboygan Reef than near shore, indicating that large (>170-mm total length) prey fish were readily available to lake trout in the reef area. On a wet-weight basis, alewife Alosa pseudoharengus dominated the diet of large (a?Y 600 mm total length) lake trout from both the nearshore and offshore regions of the lake, although bloater Coregonus hoyi composed over 30% of the diet on Sheboygan Reef and in southeastern nearshore Lake Michigan. Size of alewife prey increased with lake trout size. The bloater population currently represents the bulk of the biomass of the adult prey fish community, so our diet analysis suggests that large lake trout are continuing to select alewives.

  8. CLEAR LAKE BASIN 2000 PROJECT

    SciTech Connect

    LAKE COUNTY SANITATION DISTRICT

    2003-03-31

    The following is a final report for the Clear Lake Basin 2000 project. All of the major project construction work was complete and this phase generally included final details and testing. Most of the work was electrical. Erosion control activities were underway to prepare for the rainy season. System testing including pump stations, electrical and computer control systems was conducted. Most of the project focus from November onward was completing punch list items.

  9. DINKEY LAKES ROADLESS AREA, CALIFORNIA.

    USGS Publications Warehouse

    Dodge, F.C.W.; Federspiel, F.E.

    1984-01-01

    The Dinkey Lakes Roadless Area occupies an area of about 184 sq mi on the western slope of the Sierra Nevada, California. The results of a mineral survey show that parts of the 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.

  10. DOLUS LAKES ROADLESS AREA, MONTANA.

    USGS Publications Warehouse

    Elliott, James E.; Avery, Dale W.

    1984-01-01

    A mineral survey of the Dolus Lakes Roadless Area in southwestern Montana, was conducted. Much of the roadless area has probable and substantiated potential for resources of gold, silver, molybdenum, and tungsten. The nature of the geologic terrain indicates that there is little promise for the occurrence of coal, oil, gas, or geothermal resources. Detailed geologic and geochemical studies are suggested to delineate exploration targets that could be tested by drilling.

  11. 6. VIEW OF THREE BEARS LAKE, SHOWING WASHED UP 12' ...

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

    6. VIEW OF THREE BEARS LAKE, SHOWING WASHED UP 12' x 12' DAM SUPPORT TIMBERS, LOOKING NORTHEAST FROM SOUTH SIDE OF LAKE - Three Bears Lake & Dams, North of Marias Pass, East Glacier Park, Glacier County, MT

  12. Lake Superior Aquatic Invasive Species Complete Prevention Plan

    EPA Pesticide Factsheets

    The Lake Superior Aquatic Invasive Species Complete Prevention Plan is an expression of the best professional judgment of the members of the Lake Superior Task Force as to what is necessary to protect Lake Superior from new aquatic invasive species.

  13. BIOLOGICAL INDICATOR DEVELOPMENT AND CLASSIFICATION FOR GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    Great Lakes coastal wetlands are a valued aquatic resource that provide important ecological functions for the Great Lakes including serving as fish habitat, aquatic food web support, and nutrient and sediment retention from watersheds. Great Lakes resource managers need assessme...

  14. 40 CFR 35.1630 - State lake classification surveys.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Freshwater Lakes § 35.1630 State lake classification surveys. States that wish to participate in the clean... trophic condition, of their publicly owned freshwater lakes that are in need of restoration or...

  15. 51. Third Floor, Lake Forest, west center room, looking west, ...

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

    51. Third Floor, Lake Forest, west center room, looking west, part of original Forest Cottage as of 1901. - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  16. 5. View north, south and east facade of Lake Forest ...

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

    5. View north, south and east facade of Lake Forest (original Forest Cottage structure incorporated into renamed structure) - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  17. 7. View southwest, east facade of Lake Forest (original Forest ...

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

    7. View southwest, east facade of Lake Forest (original Forest Cottage structure incorporated into renamed structure) - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  18. 3. View northeast, west facade of Lake Forest (original Forest ...

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

    3. View northeast, west facade of Lake Forest (original Forest Cottage structure incorporated into renamed structure) - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  19. 4. View southeast, west facade of Lake Forest (original Forest ...

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

    4. View southeast, west facade of Lake Forest (original Forest Cottage structure incorporated into renamed structure) - Lake Placid Club, Forest Wing, East side of Mirror Lake Drive, North of State Route 86 & Main, North Elba, Essex County, NY

  20. 3. View north of spillway and abutment on Lake Whitney ...

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

    3. View north of spillway and abutment on Lake Whitney Dam. - Lake Whitney Water Filtration Plant, Lake Whitney Dam, East side of Whitney Avenue near intersection with Armory Street, Hamden, New Haven County, CT

  1. 2. View west of spillway and abutment on Lake Whitney ...

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

    2. View west of spillway and abutment on Lake Whitney Dam. - Lake Whitney Water Filtration Plant, Lake Whitney Dam, East side of Whitney Avenue near intersection with Armory Street, Hamden, New Haven County, CT

  2. View of upstream face of Lake Sabrina Dam showing the ...

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

    View of upstream face of Lake Sabrina Dam showing the redwood planks and base of dam from Lake Sabrina Basin, view north - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  3. View of upstream face of Lake Sabrina Dam showing redwood ...

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

    View of upstream face of Lake Sabrina Dam showing redwood planks and boulders in Lake Sabrina Basin, view north - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  4. Mercury distribution in sediment profiles of six Louisiana Lakes.

    PubMed

    Gambrell, R P; DeLaune, R D; Patrick, W H; Jugsujinda, A

    2001-05-01

    A study was conducted of six Louisiana Lakes to examine the relationship between sediment properties including mercury content and health advisories associated with mercury levels in fish. Comparison was made between three lakes with health advisories (Black Lake, Chicot Lake, and Henderson Lake) and three lakes where the levels of mercury in fish are below health advisory levels (False River, Lake St. John, and Miller Lake). Three sediment core samples were collected from each lake and sectioned into 2-cm increments to a depth of 20 cm. Sediment properties measured in each depth increment of the sediment profile included total mercury, 137Cs activity (for sedimentation rate), and sediment organic matter content. Of the lakes studied, those lakes that have health advisories for mercury tended to have higher total mercury contents, usually higher sediment organic matter contents, and higher sedimentation rates than sediments in lakes where health advisories for mercury are not issued.

  5. Taxonomic Evaluation of Cleveland Harbor Lake Areas

    DTIC Science & Technology

    2014-01-01

    Immature. Comparison to previous collections Although benthic invertebrates were not previously collected for USACE- LRB from the current study areas...areas in the lake. There were considerable differences in invertebrate community taxa between Vermillion and Cleveland Harbor, including the presence...Griffiths. 1984. Benthic invertebrates of the nearshore zone of eastern Lake Huron, Georgian Bay, and North Channel. Journal of Great Lakes Research 10:407

  6. Pacific salmonines in the Great Lakes Basin

    USGS Publications Warehouse

    Claramunt, Randall M.; Madenjian, Charles P.; Clapp, David; Taylor, William W.; Lynch, Abigail J.; Leonard, Nancy J.

    2012-01-01

    Pacific salmon (genus Oncorhynchus) are a valuable resource, both within their native range in the North Pacific rim and in the Great Lakes basin. Understanding their value from a biological and economic perspective in the Great Lakes, however, requires an understanding of changes in the ecosystem and of management actions that have been taken to promote system stability, integrity, and sustainable fisheries. Pacific salmonine introductions to the Great Lakes are comprised mainly of Chinook salmon, coho salmon, and steelhead and have accounted for 421, 177, and 247 million fish, respectively, stocked during 1966-2007. Stocking of Pacific salmonines has been effective in substantially reducing exotic prey fish abundances in several of the Great Lakes (e.g., lakes Michigan, Huron, and Ontario). The goal of our evaluation was to highlight differences in management strategies and perspectives across the basin, and to evaluate policies for Pacific salmonine management in the Great Lakes. Currently, a potential conflict exists between Pacific salmonine management and native fish rehabilitation goals because of the desire to sustain recreational fisheries and to develop self-sustaining populations of stocked Pacific salmonines in the Great Lakes. We provide evidence that suggests Pacific salmonines have not only become naturalized to the food webs of the Great Lakes, but that their populations (specifically Chinook salmon) may be fluctuating in concert with specific prey (i.e., alewives) whose populations are changing relative to environmental conditions and ecosystem disturbances. Remaining questions, however, are whether or not “natural” fluctuations in predator and prey provide enough “stability” in the Great Lakes food webs, and even more importantly, would a choice by managers to attempt to reduce the severity of predator-prey oscillations be antagonistic to native fish restoration efforts. We argue that, on each of the Great Lakes, managers are pursuing

  7. Estimated Optical Constants of Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.; Fonda, Mark (Technical Monitor)

    2002-01-01

    The visible, near-infrared, and mid-infrared (0.3-25 micron) real and imaginary indices of refraction are derived from reflectance measurements of the Tagish Lake meteorite. These are compared to some real and imaginary indices of refraction of the individual minerals composing the Tagish Lake meteorite. From this comparison it is clear that the imaginary indices of several individual minerals contribute to the estimated imaginary index of the Tagish Lake.

  8. Pulicat Lake: A Fragile Ecosystem Under Threat

    NASA Astrophysics Data System (ADS)

    Saraswathy, R.; Pandian, Pitchai Kasinatha

    2016-09-01

    The Pulicat Lake is the second largest brackish water lake after Chilika Lake in India. The average area of the water spread is 461 sq km. During the monsoon Pulicat Lake receives freshwater through three major rivers, namely, the Swarnamukhi, the Kalangi and the Arani. The Pulicat lagoon system, which is a storehouse of rich biological resources, is under great threat because of the anthropogenic influences. The Pulicat Lake ecosystem is degraded by siltation, bar mouth dynamics, shell mining and processing and population pressure due to the resettlement of villagers from Sriharikota Island. It has been determined that the extent of the lake, including its water spread area, is decreasing. Therefore, it is essential to assess the land use / land cover changes taking place in and around Pulicat Lake using remote sensing and GIS. Studies on its sediment characteristics are also vital. The grain size content reveals that most of the sediments contain clay and silt in enormous amounts. This lake has been the prime source of a livelihood through fishing for a large section of the population living in the surrounding villages. It is the most important refuge for water birds in south India. The fishing community who lives in and around Pulicat Lake follows the Padu system for fishing in the lake. In this study, apart from studies on configuration changes and sediment analysis, a study of the flora and fauna of the lake and the socio-economic conditions of the local community were also carried out. Finally, mitigation measures for the sustainable protection of the lake's ecosystem were identified.

  9. 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... Liability Act, as amended (``CERCLA''), 42 U.S.C. 9622(i), notice is hereby given of a proposed administrative settlement for recovery of past response costs concerning the Lake Linden Superfund Site in...

  10. Diet of lake trout and burbot in northern Lake Michigan during spring: Evidence of ecological interaction

    USGS Publications Warehouse

    Jacobs, Gregory R.; Madenjian, Charles P.; Bunnell, David B.; Holuszko, Jeffrey D.

    2010-01-01

    We used analyses of burbot (Lota lota) and lake trout (Salvelinus namaycush) diets taken during spring gill-net surveys in northern Lake Michigan in 2006-2008 to investigate the potential for competition and predator-prey interactions between these two species. We also compared our results to historical data from 1932. During 2006-2008, lake trout diet consisted mainly of alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), whereas burbot utilized a much wider prey base including round goby (Neogobius melanostomus), rainbow smelt, alewives, and sculpins. Using the Schoener's diet overlap index, we found a higher potential for interspecific competition in 1932 than in 2006-2008, though diet overlap was not significant in either time period. No evidence of cannibalism by lake trout or lake trout predation on burbot was found in either time period. In 2006-2008, however, lake trout composed 5.4% (by weight) of burbot diet. To determine whether this predation could be having an impact on lake trout rehabilitation efforts in northern Lake Michigan, we developed a bioenergetic-based consumption estimate for burbot on Boulder Reef (a representative reef within the Northern Refuge) and found that burbot alone can consume a considerable proportion of the yearling lake trout stocked annually, depending on burbot density. Overall, we conclude that predation, rather than competition, is the more important ecological interaction between burbot and lake trout, and burbot predation may be contributing to the failed lake trout rehabilitation efforts in Lake Michigan.

  11. 78 FR 72706 - Notice of Inventory Completion: Michigan State Police, Houghton Lake Post, Houghton Lake, MI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-03

    ... National Park Service Notice of Inventory Completion: Michigan State Police, Houghton Lake Post, Houghton Lake, MI AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Michigan State Police, Houghton Lake Post has completed an inventory of human remains, in consultation with the appropriate...

  12. Hydrogeologic controls on the groundwater interactions with an acidic lake in karst terrain, Lake Barco, Florida

    USGS Publications Warehouse

    Lee, T.M.

    1996-01-01

    Transient groundwater interactions and lake stage were simulated for Lake Barco, an acidic seepage lake in the mantled karst of north central Florida. Karst subsidence features affected groundwater flow patterns in the basin and groundwater fluxes to and from the lake. Subsidence features peripheral to the lake intercepted potential groundwater inflow and increased leakage from the shallow perimeter of the lake bed. Simulated groundwater fluxes were checked against net groundwater flow derived from a detailed lake hydrologic budget with short-term lake evaporation computed by the energy budget method. Discrepancies between modeled and budget- derived net groundwater flows indicated that the model underestimated groundwater inflow, possibly contributed to by transient water table mounding near the lake. Recharge from rainfall reduced lake leakage by 10 to 15 times more than it increased groundwater inflow. As a result of the karst setting, the contributing groundwater basin to the lake was 2.4 ha for simulated average rainfall conditions, compared to the topographically derived drainage basin area of 81 ha. Short groundwater inflow path lines and rapid travel times limit the contribution of acid-neutralizing solutes from the basin, making Lake Barco susceptible to increased acidification by acid rain.

  13. EPA Directs DuPont to Remove Mercury from Pompton Lake in Pompton Lakes, New Jersey

    EPA Pesticide Factsheets

    (New York, N.Y.) The U.S. Environmental Protection Agency today released its final plan to remove mercury contamination from areas of Pompton Lake in Pompton Lakes, New Jersey, including the areas where the Acid Brook flows into the lake, called the Acid B

  14. 33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... monitor: (1) Channel 11 (156.55 mhz) between Lake Huron Cut Lighted Buoy 11 and Lake St. Clair Light; and (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Report. Stag Island Upper Light Report. Report Marine City Salt Dock Light Report. Report Grande...

  15. Thiamine concentrations in lake whitefish eggs from the upper Great Lakes are related to maternal diet

    USGS Publications Warehouse

    Riley, S.C.; Rinchard, J.; Ebener, M.P.; Tillitt, D.E.; Munkittrick, K.R.; Parrott, J.L.; Allen, J.D.

    2011-01-01

    Thiamine deficiency is responsible for reproductive impairment in several species of salmonines in the Great lakes, and is thought to be caused by the consumption of prey containing thiaminase, a thiamine-degrading enzyme. Because thiaminase levels are extremely high in dreissenid mussels, fish that prey on them may be susceptible to thiamine deficiency. We determined thiamine concentrations in lake whitefish Coregonus clupeaformis eggs from the upper Laurentian Great Lakes to assess the potential for thiamine deficiency and to determine if thiamine concentrations in lake whitefish eggs were related to maternal diet. Mean thiamine concentrations in lake whitefish eggs were highest in Lake Huron, intermediate in Lake Superior, and lowest in Lake Michigan. Some fish had thiamine concentrations below putative thresholds for lethal and sublethal effects in salmonines, suggesting that some larval lake whitefish may currently be at risk of at least sublethal effects of low thiamine concentrations, although thiamine thresholds are unknown for lake whitefish. Egg thiamine concentrations in lake whitefish eggs were statistically significantly related to isotopic carbon signatures, suggesting that egg thiamine levels were related to maternal diet, but low egg thiamine concentrations did not appear to be associated with a diet of dreissenids. Egg thiamine concentrations were not statistically significantly related to multifunction oxidase induction, suggesting that lower egg thiamine concentrations in lake whitefish were not related to contaminant exposure.

  16. ATMOSPHERIC MERCURY DEPOSITION TO LAKE MICHIGAN DURING THE LAKE MICHIGAN MASS BALANCE STUDY

    EPA Science Inventory

    Wet and dry mercury (Hg) deposition were calculated to Lake Michigan using a hybrid receptor modeling framework. The model utilized mercury monitoring data collected during the Lake Michigan Mass Balance Study and the Atmospheric Exchange Over Lakes and Oceans Study together w...

  17. DEVELOPMENT AND EVALUATION OF THE LAKE MACROINVERTEBRATE INTEGRITY INDEX (LMII) FOR NEW JERSEY LAKES AND RESERVOIRS

    EPA Science Inventory

    In response to the recent focus by the U.S. Environmental Protection Agency on bioassessment of lakes, a multimetric index was developed for New Jersey lakes and reservoirs using benthic macroinvertebrates. Benthic samples were collected from reference and impaired lakes with mu...

  18. Water analysis methods at the integrated Lake Watershed Acidification Study Laboratory, Raquette Lake, NY

    SciTech Connect

    Tokos, J.

    1980-09-01

    The materials, equipment, and methods used by Brookhaven National Laboratory personnel for routine chemical and biological analyses in the three lakes of the Integrated Lake Watershed Acidification Study are described. The procedures apply to pelagic samples taken from Panther, Sagamore, and Woods Lakes. Separate sections outlining benthic primary production and inlet-outlet methods are included.

  19. Lake Michigan lake trout PCB model forecast post audit (oral presentation)

    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 an...

  20. Analysis of Poyang Lake water balance and its indication of river-lake interaction.

    PubMed

    Zhang, Zengxin; Huang, Yuhan; Xu, Chong-Yu; Chen, Xi; Moss, Elica M; Jin, Qiu; Bailey, Alisha M

    2016-01-01

    In recent years, water shortage is becoming one of the most serious problems in the Poyang Lake. In this paper, the long-term water balance items of the Poyang Lake have been analyzed to reveal the coupling effects of Three Gorges Dam (TGD) and droughts on the water balance of Poyang Lake. The results indicate that: (1) the water balance items of Poyang Lake vary greatly, e.g. lake precipitation and inflow decrease during the past several decades while evaporation and water consumption increase significantly; (2) the water balance of Poyang Lake has been affected by the operation of TGD. Negative lake water balance in recent years leads to a serious water shortage problem in the Poyang Lake. Moreover, the operation of TGD also changed the river-lake relationship in the lower Yangtze River basin; (3) the coupling effects of drought and TGD on the lake water balance has been analyzed by using composite analysis method and it can be found that the operation of TGD has significantly altered the lake water balance. But it is not the only factor that affects the lake water balance, and the droughts might cause their relations to be much more complicated.

  1. 78 FR 17869 - Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu City, AZ

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-25

    ... establishing a temporary safety zone on the navigable waters of the Colorado River in Lake Havasu, Lake Havasu... LLC is sponsoring the Desert Storm Shootout, which is to be held on the Colorado River in Lake Havasu... vessels intending to transit or anchor in a portion of the Colorado River from 8 a.m. to 6 p.m. on...

  2. National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States

    EPA Science Inventory

    The National Lakes Assessment 2012: A Collaborative Survey of Lakes in the United States presents the results of a second evaluation of the lakes in the United States. This report is part of the National Aquatic Resource Surveys, a series of statistically based surveys designed t...

  3. 33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... monitor: (1) Channel 11 (156.55 mhz) between Lake Huron Cut Lighted Buoy 11 and Lake St. Clair Light; and (2) Channel 12 (156.60 mhz) between Lake St. Clair Light and Detroit River Light. (b) Radiotelephone... Report. Stag Island Upper Light Report. Report Marine City Salt Dock Light Report. Report Grande...

  4. LAKE-WETLAND LINKAGE AND PERIPHYTON DYNAMICS IN A LAKE SUPERIOR COASTAL WETLAND

    EPA Science Inventory

    Tributaries feeding coastal wetlands along the Wisconsin shore of Lake Superior are generally depleted in inorganic nitrogen (TIN) relative to phosphorus (SRP), while Lake Superior is phosphorous depleted and relatively rich in TIN. Within wetlands, mixing of tributary and lake w...

  5. 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 and Arizona. 110.127 Section 110.127 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore...

  6. 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 and Arizona. 110.127 Section 110.127 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore...

  7. 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 and Arizona. 110.127 Section 110.127 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore...

  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 and Arizona. 110.127 Section 110.127 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Mead, Nevada and Arizona. (a) Willow Beach, Ariz. That portion of Lake Mohave enclosed by the shore...

  9. Growth and potential yield of perch (Perca spp.) in selected areas of Lake Baikal and the Laurentian Great Lakes

    USGS Publications Warehouse

    O'Gorman, Robert; Bronte, Charles R.; Hatcher, Charles O.; Pronin, Nikolai M.; Sokolnikov, Yury

    1998-01-01

    We compared growth, mortality, and potential yield of Eurasian perch (Perca fluviatilis) from Chivirkui Bay in Lake Baikal with that of yellow perch (P. flavescens) from three areas of the Laurentian Great Lakes --Chequamegon Bay in Lake Superior, northeastern Lake Ontario, and southwestern Lake Erie. Graded mesh gill nets were fished in August to sample perch in lakes Baikal (1993), Ontario (1985-93), and Erie (1994). Bottom trawls were fished in July-August to sample perch in Lake Superior (1973-93). Adult yellow perch from the Laurentian Great Lakes were heavier at most lengths than adult Eurasian perch from Lake Baikal. The increase in body weight per unit increase in length was greatest in Lake Erie. Total annual mortality of perch was low in Lake Baikal (0.31), intermediate in lakes Superior (0.41) and Ontario (0.54), and high in Lake Erie (0.66). Annual fishing mortality (u) for perch in Lake Baikal was 60%-70% lower than that for perch in the Great Lakes. At ages 1-3, perch in Lake Erie were longer than those in lakes Baikal, Superior, and Ontario but at ages 4-9 perch in Lake Baikal were longer than those in the other lakes. Although Eurasian perch in Lake Baikal were longer at age 4 and older, growth in length, as measured by the Brody growth coefficient, K, was lower there than in the other lakes and was similar to that in Lake Superior; yellow perch in Lake Erie grew the fastest. Yield-per-recruit was lowest in Lake Erie and highest in Lake Superior. Potential yield was influenced by growth rates and fishing mortality.

  10. Blanket of Snow Covers Salt Lake City

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On December 23, 2001, less than two months before the start of the 2002 Winter Olympics, snow blankets Salt Lake City and the surrounding area. The Great Salt Lake, on the left hand side of the image above, often contributes to the region's snowfall through the 'lake-effect.' As cold air passes over a large body of water it both warms and absorbs moisture. The warm air then rises (like a hot air balloon) and cools again. As it cools, the water vapor condenses out, resulting in snowfall. Just to the east (right) of the Great Salt Lake the mountains of the Wasatch Range lift air from the lake even higher, enhancing the lake-effect, resulting in an average snowfall of 64 inches a year in Salt Lake City and 140 inches in Park City, which is located at the foot of the Wasatch Front. For more information about the lake-effect, read Lake-Effect Snowfalls. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  11. Rapid discharge connects Antarctic subglacial lakes.

    PubMed

    Wingham, Duncan J; Siegert, Martin J; Shepherd, Andrew; Muir, Alan S

    2006-04-20

    The existence of many subglacial lakes provides clear evidence for the widespread presence of water beneath the East Antarctic ice sheet, but the hydrology beneath this ice mass is poorly understood. Such knowledge is critical to understanding ice flow, basal water transfer to the ice margin, glacial landform development and subglacial lake habitats. Here we present ice-sheet surface elevation changes in central East Antarctica that we interpret to represent rapid discharge from a subglacial lake. Our observations indicate that during a period of 16 months, 1.8 km3 of water was transferred over 290 km to at least two other subglacial lakes. While viscous deformation of the ice roof above may moderate discharge, the intrinsic instability of such a system suggests that discharge events are a common mode of basal drainage. If large lakes, such as Lake Vostok or Lake Concordia, are pressurizing, it is possible that substantial discharges could reach the coast. Our observations conflict with expectations that subglacial lakes have long residence times and slow circulations, and we suggest that entire subglacial drainage basins may be flushed periodically. The rapid transfer of water between lakes would result in large-scale solute and microbe relocation, and drainage system contamination from in situ exploration is, therefore, a distinct risk.

  12. CHINESE PLAT, 1919 (L19 19 4 E, SALT LAKE CITY ...

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

    CHINESE PLAT, 1919 (L19 19 4 E, SALT LAKE CITY CEMETERY LOCATER), SALT LAKE CITY, UT. VIEW LOOKING NORTHEAST AT CHINESE PLAT MARKER AND BURNER. - Salt Lake City Cemetery, 200 N Street, Salt Lake City, Salt Lake County, UT

  13. Red River of the North Reconnaissance Report: Red Lake River.

    DTIC Science & Technology

    1980-12-01

    The two lakes are remnants of glacial Lake Agassiz and together comprise the largest lake area wholly contained in Minnesota. Biology The principal...Red River Valley Laku Plain, Glacial Lake Agassiz Beachlines, Aspen Parklands, Glacial Lake Agassiz Lowlands, Border-Prairie Transition, and North...Areas of particular aesthetic appeal include Agassiz National Wildlife Refuge, seven state forests, Upper and Lower Red Lakes, and the natural wooded

  14. Holocene Lake Records on Kamchatka

    NASA Astrophysics Data System (ADS)

    Diekmann, Bernhard; Biskaborn, Boris; Chapligin, Bernhard; Dirksen, Oleg; Dirksen, Veronika; Hoff, Ulrike; Meyer, Hanno; Nazarova, Larisa

    2014-05-01

    The availibility of terrestrial records of Holocene palaeoenvironmental changes in eastern Siberia still is quite limited, compared to other regions on the northern hemisphere. In particular, the Kamchatka Peninsula as an important climate-sensitive region is very underrepresented. Situated at the border of northeastern Eurasia, the maritime-influenced terrestrial setting of Kamchatka offers the potential to pinpoint connections of environmental changes between the periglacial and highly continental landmasses of eastern Siberia and the sub-Arctic Pacific Ocean and Sea of Okhotsk. The study region lies at the eastern end-loop of the global thermohaline ocean conveyor belt and is strongly affected by atmospheric teleconnections. Volcanic, tectonic, and glacial processes overprint palaeoenvironmental changes in addition to primary climate forcing. In order to widen our understanding of plaeoclimate dynamics on Kamchatka, sediment cores from different lake systems and peat sections were recovered and analysed by a multi-proxy approach, using sedimentological and geochemical data as well as fossil bioindicators, such as diatoms, pollen, and chironomids. Chronostratigraphy of the studied records was achieved through radiocarbon dating and tephrostratigraphy. Sediment cores with complete Holocene sedimentary sequences were retrieved from Lake Sokoch, an up to six metre deep lake of proglacial origin, situated at the treeline in the Ganalsky Ridge of southern central Kamchatka (53°15,13'N, 157°45.49' E, 495 m a.s.l.). Lacustrine sediment records of mid- to late Holocene age were also recovered from the up to 30 m deep Two-Yurts Lake, which occupies a former proglacial basin at the eastern flank of the Central Kamchatka Mountain Chain, the Sredinny Ridge (56°49.6'N, 160°06.9'E, 275 m a.s.l.). In addition to sediment coring in the open and deep Two-Yurts Lake, sediment records were also recovered from peat sections and small isolated forest lakes to compare

  15. Reconstruction of the geology and structure of Lake Rotomahana and its hydrothermal systems from high-resolution multibeam mapping and seismic surveys: Effects of the 1886 Tarawera Rift eruption

    NASA Astrophysics Data System (ADS)

    de Ronde, C. E. J.; Walker, S. L.; LeBlanc, C.; Davy, B. W.; Fornari, D. J.; Tontini, F. Caratori; Scott, B. J.; Seebeck, H.; Stewart, T. J.; Mazot, A.; Nicol, A.; Tivey, M. A.

    2016-03-01

    Present-day Lake Rotomahana is one of the two focal points of the most destructive eruption in New Zealand's historical record, i.e., that of Mt. Tarawera on 10 June 1886, with devastating loss of life and presumed destruction of the iconic Pink and White Terraces that adorned the margins of the lake. Basaltic dikes are considered to have ascended near surface in the area, intruding into hydrothermally altered and water-saturated ground beneath the existing lake. The consequential hydrothermal and phreatomagmatic eruptions ejected 0.5325 km3 of material from the lakefloor and below, plastering the nearby landscape for several kilometers with mud and other debris. The eruption buried the natural outlet of the lake, with the bottom of the craters becoming filled by water within months and completely concealed from view within years; today Lake Rotomahana has depths up to 118 m. High-resolution (0.5 m) bathymetric mapping, when combined with a 2-D seismic reflection survey, enables us to 'see' details of the maar craters on the lakefloor, including those parts subsequently buried by sediment. The large Rotomahana Crater described by workers immediately after the eruption measures ~ 2.5 km in diameter near its southwestern end, and excavated ground to 155 m below present-day lake level. The vent system, as revealed by the present study, forms an array of right-stepping (dextral) craters, with the main crater being host to two sub-craters Rotomahana West Crater and Rotomahana East Crater today buried beneath the lakefloor, and which are in-filled by 36 and 37 m of sediment, respectively. Subordinate craters along the same 057° Tarawera Rift trace include Hochstetter Crater (11 m of infill), Waingongongongo Crater (14 m) and Rotomakariri Crater (26 m). These craters host a total 0.0268 km3 of sediment. Other features highlighted by the bathymetric data include; craters not filled by sediment, sediment fan deltas, volcanic ridges and dikes, submerged wave-cut terraces

  16. Genetic strategies for lake trout rehabilitation: a synthesis

    USGS Publications Warehouse

    Burnham-Curtis, Mary K.; Krueger, Charles C.; Schreiner, Donald R.; Johnson, James E.; Stewart, Thomas J.; Horrall, Ross M.; MacCallum, Wayne R.; Kenyon, Roger; Lange, Robert E.

    1995-01-01

    The goal of lake trout rehabilitation efforts in the Great Lakes has been to reestablish inshore lake trout (Salvelinus namaycush) populations to self-sustaining levels. A combination of sea lamprey control, stocking of hatchery-reared lake trout, and catch restrictions were used to enhance remnant lake trout stocks in Lake Superior and reestablish lake trout in Lakes Michigan, Huron, Erie, and Ontario. Genetic diversity is important for the evolution and maintenance of successful adaptive strategies critical to population restoration. The loss of genetic diversity among wild lake trout stocks in the Great Lakes imposes a severe constraint on lake trout rehabilitation. The objective of this synthesis is to address whether the particular strain used for stocking combined with the choice of stocking location affects the success or failure of lake trout rehabilitation. Poor survival, low juvenile recruitment, and inefficient habitat use are three biological impediments to lake trout rehabilitation that can be influenced by genetic traits. Evidence supports the hypothesis that the choices of appropriate lake trout strain and stocking locations enhance the survival of lake trout stocked into the Great Lakes. Genetic strategies proposed for lake trout rehabilitation include conservation of genetic diversity in remnant stocks, matching of strains with target environments, stocking a greater variety of lake trout phenotypes, and rehabilitation of diversity at all trophic levels.

  17. Planning Interventions for Lake Conservation: A Case of Shahpura Lake, Bhopal, India

    NASA Astrophysics Data System (ADS)

    Munoth, Navneet; Nagaich, Anugrah Anilkumar

    2015-09-01

    With due increment in the development process of India, the problems related to environment are under constant increment and its contamination has now became a great threat for the rich ecology of the country. Particularly, the problems regarding the water quality are now becoming more acute and complicated due to increasing urbanization, industrialization, siltation, agricultural run-off and discharge of untreated sewage water. The city Bhopal in India having named as the city of lakes, is also experiencing similar issues. The famous characteristic lakes of Bhopal are under great environmental stress due to pollution from various sources. The Shahpura lake is one such lake, situated well within the city. A number of wards and colonies surrounding the lake boundary discharge their sewage and silage into the existing drainage network of the area, which ultimately finds its way into the lake through open drains. The main source of contamination in the lake is sewage fed drains, which are dumped into the lake during the summers. Besides this, other activities like bathing, cloth washing, cattle bathing and religious activities like idol immersion etc. also paves the way for high concentration of harmful chemicals in the lake. This work mainly discusses the existing situation and causes of water pollution in the Shahpura lake of Bhopal. It also brings into light the constitutional safeguards related to Lake Conservation in India and reviews their practical implications. In the end, it focuses on recommending the lake conservation strategies for the case of Shahpura lake; and suggests measures that could be adopted elsewhere to prevent the issue of lake pollution from various sources, emphasizing the importance of lakes.

  18. Tagging experiments with lake trout, whitefish, and other species of fish from Lake Michigan

    USGS Publications Warehouse

    Smith, Oliver H.; Van Oosten, John

    1940-01-01

    A total of 2,902 Lake Michigan fish was tagged and released, 48.8 per cent of which were lake trout and 85 per cent lake trout, lake herring, and whitefish. A total of 388 fish or 13.4 per cent was recaptured. The percentages of returns indicated a tremendous fishing intensity for lake trout, whitefish, and sturgeon. About 81 per cent of the recaptured fish were retaken within a radius of 25 miles from the port of tagging (Port Washington, Wisconsin). Lake trout, rainbow trout, and sturgeon were found to be extensive travelers; lake herring, whitefish, chubs, pilots, and perhaps perch did not migrate so extensively. Lake trout, herring, and whitefish tended to move in a northerly direction, perch in a southerly, and rainbow trout in all easterly, toward the Michigan shore. Sturgeon apparently roam all over the lake. Fifty-three per cent of the recovered lake trout were recaptured within one year of release, 73 per cent within 25 miles from Port Washington. It required three years for the trout to become fairly well scattered throughout the lake. With the attainment of adulthood lake trout moved in all directions from the port of release, although nearly 50 per cent of the adults were retaken within 25 miles from this port. Fish moved across state boundaries. Data are given on the growth and estimated age of the tagged lake trout, rainbow trout, whitefish, and sturgeon. The minimum size limits of lake trout and whitefish on the Great Lakes are economically unsound–they are too low–because they permit the capture of these species at a time of most rapid increase in weight.

  19. HISTORICAL SNOW AMOUNTS IN THE LAKE EFFECT REGION OF LAKE SUPERIOR: EVIDENCE OF CLIMATE CHANGE IN THE GREAT LAKES

    EPA Science Inventory

    Recent studies (Levitus et al., .2000) suggest a warming of the world ocean over the past 50 years. This could be occurring in the Great Lakes also but thermal measurements are lacking. Historical trends in natural phenomena, such as the duration of ice cover on lakes, provide in...

  20. Wave Information Studies of US Coastlines: Hindcast Wave Information for the Great Lakes: Lake Superior

    DTIC Science & Technology

    1992-01-01

    SWAVE INFORMATION STUDIES OF US COASTLINES AD-A248 002 wsREPORT 23IIIE11I1K1E1E1 UIIE UL III HINDCAST WAVE INFORMATION FOR THE GREAT LAKES : LAKE ...Hindcast Wave Information for the Great Lakes : Lake Superior 6. AUTHOR(S) David B. Driver, Robin D. Reinhard, Jon M. Hubertz 7. PERFORMING...information is summarized for 95 locations along the shoreline of Lake Superior in four data products: percent occurrence tables, wave rose diagrams, mean and