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Sample records for fontana lake region

  1. Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

    NASA Astrophysics Data System (ADS)

    Lanfranchini, Mabel Elena; Etcheverry, Ricardo Oscar; de Barrio, Raúl Ernesto; Recio Hernández, Clemente

    2013-04-01

    Precious metal-bearing quartz veins occur at the northeastern sector of the Lago Fontana region in southwestern Argentina, within the context of the Andean continental magmatic arc environment. The deposits and their associated alteration zones are spatially related to a Cretaceous calc-alkaline magmatism represented by silicic dikes and hypabyssal intrusions, and hosted by a Late Jurassic to Cretaceous volcano-sedimentary sequence. The veins and related veinlets crop out discontinuously, in general terms in a NW-SE belt. The primary vein mineral assemblage is composed mostly of pyrite ± galena ± chalcopyrite > hematite ± arsenopyrite in silica gangue minerals. Chemical analyses of grab samples from selected quartz veins show as much as 5.7 ppm Au and 224 ppm Ag, as well as elevated Pb, Cu, and Zn. Hydrothermal fluids caused an innermost silicification and adularia-sericite alteration assemblage, and an external propylitic halo. Sulfur isotope values measured for sulfides (δSS from -1.90 to +1.56‰), and oxygen and hydrogen isotopes measured on quartz crystals and extracted primary fluid inclusion waters (δOO = -2.85 to +5.40‰; δDO = -106.0 to -103.4‰) indicate that mineralization probably formed from magmatic fluids, which were mixed with meteoric waters. Also, fluid inclusion data from quartz veins point out that these fluids had low salinity (1.7-4.2 wt% NaCl equiv.), and temperatures of homogenization between 180 and 325 °C. Mineralogical, petrographic and geochemical features for mineralized surface exposures indicate a typical adularia-sericite, low sulfidation epithermal system in the Lago Fontana area that represents a promising target for further exploration programs.

  2. 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 ...

  3. [Felice Fontana precursor of neurosciences (author's transl)].

    PubMed

    Disertori, B; Piazza, M

    1981-01-01

    The A.A. insert the life and work of the naturalist and chemist Felice Fontana, born in Pomarolo (Trentino), in the frame of 18th century sciences, beside other great names of that century like Carolus Linnaeus, Réaumur, von Haller, Spallanzani, Morgagni, Priestley and Lavoisier. In the field of general biology, the discovery of nucleus and nucleolus and consequently the discovery of the eukaryotic cell, as we say in our days, in his, as well as the one of anabiosis. The A.A. enucleate and analyse the contributions of Fontana to the neurosciences; he has discovered the axon and the myelinic sheath half century before Remak and Purknije; he found out that the white matter of the brain is made of fibres alike those of nerves and the grey matter is made of globules (i.e. cells) mixed up with fibres; he discovered in the retina a part of coming out from the brain; he described the transversal bands of fibres of the skeletal muscles; he was the first to introduce into physiology the law of "all and nothing"; he attributed the irritability to the whole animal life; he identified the pupillar reflexes to the light, the reflex of accommodation, the consensual reflex, the psycho-emotive mydriasis and at last the myosis of sleep. He made experimental searches about nerves and recognised their regeneration, he enumerated various pathological intracranial masses, he made an important anatomopathological research about hydatid cyst in the brain of the sheep affected by "capostorno" and madness, he demonstrated their parasitical nature (he said that the hydated cysts were covered inside by small animals), he come out to formulate the hypothesis that some neuropsychiatric diseases of man can depend from similar aetiology. He declared that passions may have pathological effects (psyco-somatic aetiology), but he has also drawned the attention against the danager of aprioristical generalisation of neurogenical causes in all diseases. The A.A. give to Fontana the palm of precursor

  4. 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.).

  5. Potential Impacts of Climate Change in the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Winkler, J. A.

    2011-12-01

    Climate change is projected to have substantial impacts in the Great Lakes region of the United States. One intent of this presentation is to introduce the Great Lakes Integrated Sciences and Assessments Center (GLISA), a recently-funded NOAA RISA center. The goals and unique organizational structure of GLISA will be described along with core activities that support impact and assessment studies in the region. Additionally, observed trends in temperature, precipitation including lake effect snowfall, and lake temperatures and ice cover will be summarized for the Great Lakes region, and vulnerabilities to, and potential impacts of, climate change will be surveyed for critical natural and human systems. These include forest ecosystems, water resources, traditional and specialized agriculture, and tourism/recreation. Impacts and vulnerabilities unique to the Great Lakes region are emphasized.

  6. Local versus regional coherence in meteorological variables and lake temperatures

    SciTech Connect

    Benson, B.J.; Kratz, T.K.; Dillon, P. |

    1995-06-01

    Lakes are affected by many driving variables, some acting locally, some regionally. Meteorological variables and lake temperature profiles from long-term data sets collected at four research sites across the Great Lakes Region (the North Temperate Lakes LTER sites in northern and southern Wisconsin, and the Experimental Lakes Area and Dorset Research Area in Canada) were analyzed to test whether inter-annual variation in meteorological variables (air temperature and solar radiation), lake temperature, and mixed layer depth was temporally coherent, i.e. exhibited synchronous variation. Coherence is an important property to evaluate because it influences how broadly we can extrapolate results from a lake or set of lakes and it clarifies what aspects of climate are linked to lake dynamics. Results to date show strong coherence, as measured by high correlation values, of air temperature among the four areas. Summer surface temperature was strongly coherent for lakes within a research site and moderately coherent among some of the sites whereas hypolimnion temperature was not as coherent. Thus lake thermal variables range from being tightly linked to climate to relatively disconnected from regional climatic variation.

  7. A Dynamical Downscaling study over the Great Lakes Region Using WRF-Lake: Historical Simulation

    NASA Astrophysics Data System (ADS)

    Xiao, C.; Lofgren, B. M.

    2014-12-01

    As the largest group of fresh water bodies on Earth, the Laurentian Great Lakes have significant influence on local and regional weather and climate through their unique physical features compared with the surrounding land. Due to the limited spatial resolution and computational efficiency of general circulation models (GCMs), the Great Lakes are geometrically ignored or idealized into several grid cells in GCMs. Thus, the nested regional climate modeling (RCM) technique, known as dynamical downscaling, serves as a feasible solution to fill the gap. The latest Weather Research and Forecasting model (WRF) is employed to dynamically downscale the historical simulation produced by the Geophysical Fluid Dynamics Laboratory-Coupled Model (GFDL-CM3) from 1970-2005. An updated lake scheme originated from the Community Land Model is implemented in the latest WRF version 3.6. It is a one-dimensional mass and energy balance scheme with 20-25 model layers, including up to 5 snow layers on the lake ice, 10 water layers, and 10 soil layers on the lake bottom. The lake scheme is used with actual lake points and lake depth. The preliminary results show that WRF-Lake model, with a fine horizontal resolution and realistic lake representation, provides significantly improved hydroclimates, in terms of lake surface temperature, annual cycle of precipitation, ice content, and lake-effect snowfall. Those improvements suggest that better resolution of the lakes and the mesoscale process of lake-atmosphere interaction are crucial to understanding the climate and climate change in the Great Lakes region.

  8. Evaporation study in a humid region, Lake Michie, North Carolina

    USGS Publications Warehouse

    Turner, J.F., Jr.

    1966-01-01

    The mass-transfer and water-budget techniques of calibrating a reservoir for evaporation were evaluated through a study of Lake Michie, N.C. The techniques appear adequate for estimation of lake evaporation and net seepage in humid regions where lake storage is affected by streamflow and ground-water seepage, under conditions no more adverse than those affecting Lake Michie. The analysis of 25 months of mass-transfer and water-budget data collected at Lake Michie indicates pronounced seasonal variation in both evaporation and seepage.

  9. Eighteen Years of the Great Lakes Regional Counseling Psychology Conference: Revisiting the Need for Regional Conferences

    ERIC Educational Resources Information Center

    Delgado-Romero, Edward A.; Bowman, Sharon L.; Gerstein, Lawrence H.

    2006-01-01

    The Great Lakes Regional Conference on Counseling Psychology is the only conference to continuously fulfill the 1987 mandate issued by Division 17 for regional counseling conferences. The rationale for regional conferences is reviewed, and the 18-year history of the Great Lakes Regional Conference is examined. The authors conclude by noting the…

  10. GREAT LAKES REGIONAL ASSESSMENT: REPORT OF A WORKSHOP ON CLIMATE CHANGE IN THE UPPER GREAT LAKES REGION

    EPA Science Inventory

    The Upper Great Lakes workshop, sponsored by the U.S. Environmental Protection Agency (USEPA), was held at the University of Michigan in Ann Arbor, Michigan from 4-7 May 1998 to discuss some of the potential consequences of climate change in the Upper Great Lakes region (e.g., Mi...

  11. Forecasting Lake-Effect Precipitation in the Great Lakes Region Using NASA Enhanced-Satellite Data

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    Lake-effect precipitation is common in the Great Lakes region, particularly during the late fall and winter. The synoptic processes of lake-effect precipitation are well understood by operational forecasters, but individual forecast events still present a challenge. Locally run, high resolution models can assist the forecaster in identifying the onset and duration of precipitation, but model results are sensitive to initial conditions, particularly the assumed surface temperature of the Great Lakes. The NASA Short-term Prediction Research and Transition (SPoRT) Center has created a Great Lakes Surface Temperature (GLST) composite, which uses infrared estimates of water temperatures obtained from the MODIS instrument aboard the Aqua and Terra satellites, other coarser resolution infrared data when MODIS is not available, and ice cover maps produced by the NOAA Great Lakes Environmental Research Lab (GLERL). This product has been implemented into the Weather Research and Forecast (WRF) model Environmental Modeling System (WRF-EMS), used within forecast offices to run local, high resolution forecasts. The sensitivity of the model forecast to the GLST product was analyzed with a case study of the Lake Effect Storm Echinacea, which produced 10 to 12 inches of snowfall downwind of Lake Erie, and 8 to 18 inches downwind of Lake Ontario from 27-29 January 2010. This research compares a forecast using the default Great Lakes surface temperatures from the Real Time Global sea surface temperature (RTG SST), in the WRF-EMS model to the enhanced NASA SPoRT GLST product to study forecast impacts. Results from this case study show that the SPoRT GLST contained less ice cover over Lake Erie and generally cooler water temperatures over Lakes Erie and Ontario. Latent and sensible heat fluxes over Lake Ontario were decreased in the GLST product. The GLST product decreased the quantitative precipitation forecast (QPF), which can be correlated to the decrease in temperatures and heat

  12. Great Lakes nearshore-offshore: Distinct water quality regions

    EPA Science Inventory

    We compared water quality of nearshore regions in the Laurentian Great Lakes to water quality in offshore regions. Sample sites for the nearshore region were from the US EPA National Coastal Condition Assessment and based on a criteria or sample-frame of within the 30-m depth co...

  13. Geochemical features of Kulunda plain lakes (Altay region, Russia)

    NASA Astrophysics Data System (ADS)

    Kolpakova, M. N.; Shvartsev, S. L.; Borzenko, S. V.; Isupov, V. P.; Shatskaya, S. S.

    2016-03-01

    Geochemical specifics of lake water of the Kulunda Steppe territory (Altay region, Russia) are studied. The results show that in the territory mainly chloride and less soda lakes with sodium compound are developed. It is presented that calcite and soda saturation indexes (SI) of lake water increase with growth of pH, but decrease in such minerals as gypsum and barite. The opposite situation is typical for SI depending on the salinity. It is revealed that evaporation, secondary mineral formation and various biological processes have the greatest impact on accumulation of elements in solution.

  14. Winter and Summer Views of the Salt Lake Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera. Salt Lake City, situated near the southeastern shore of the Great Salt Lake, is host to the 2002 Winter Olympic Games, which open Friday, February 8. Venues for five of the scheduled events are at city (indoor) locations, and five in mountain (outdoor) facilities. All ten can be found within the area contained in these images. Some of the outdoor events take place at Ogden, situated north of Salt Lake City and at Park City, located to the east. Salt Lake City is surrounded by mountains including the Wasatch Range to the east, and the temperature difference between the Great Salt Lake and the overlying atmosphere enhances the moisture content of winter storms. These factors, in combination with natural cloud seeding by salt crystals from the lake, are believed to result in greater snowfall in neighboring areas compared to more distant locales. In addition to the obvious difference in snow cover between the winter and summer views, water color changes in parts of the Great Salt Lake are apparent in these images. The distinctly different coloration between the northern and southern arms of the Great Salt Lake is the result of a rock-filled causeway built in 1953 to support a permanent railroad. The causeway has resulted in decreased circulation between the two arms and higher salinity on the northern side. The southern part of the lake includes the large Antelope Island, and at full resolution a bridge connecting it to the mainland can be discerned. These images are natural color views acquired on February 8, 2001 and June 16, 2001, respectively. Each image represents an area of about 220 kilometers x 285 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team.

  15. Influence of the Laurentian Great Lakes on Regional Climate

    NASA Astrophysics Data System (ADS)

    Notaro, M.; Holman, K.; Zarrin, A.; Fluck, E.; Vavrus, S. J.; Bennington, V.

    2012-12-01

    The influence of the Laurentian Great Lakes on climate is assessed by comparing two decade-long simulations, with the lakes either included or excluded, using the Abdus Salam International Centre for Theoretical Physics Regional Climate Model Version 4. The Great Lakes dampen the variability in near-surface air temperature across the surrounding region, while reducing the amplitude of the diurnal cycle and annual cycle of air temperature. The impacts of the Great Lakes on the regional surface energy budget include an increase (decrease) in turbulent fluxes during the cold (warm) season and an increase in surface downward shortwave radiation flux during summer due to diminished atmospheric moisture and convective cloud amount. Changes in the hydrologic budget due to the presence of the Great Lakes include increases in evaporation and precipitation during October-March and decreases during May-August, along with springtime reductions in snowmelt-related runoff. Circulation responses consist of a regionwide decrease in sea-level pressure in autumn-winter and an increase in summer, with enhanced ascent and descent in the two seasons, respectively. The most pronounced simulated impact of the Great Lakes on synoptic systems traversing the basin is a weakening of cold-season anticyclones.

  16. The Effect of Lake Temperatures and Emissions on Ozone Exposure in the Western Great Lakes Region

    SciTech Connect

    Fast, Jerome D. ); Heilman, Warren E.

    2003-09-01

    A meteorological-chemical model with a 12-km horizontal grid spacing was used to simulate the evolution of ozone over the western Great Lakes region during a 30-day period in the summer of 1999. High ozone production rates were produced over the surface of the lakes as a result of stable atmospheric conditions that trapped ozone precursors within a shallow layer during the day. Simulations with lake temperatures derived from either satellite measurements or climatological values produced ozone mixing ratios over the lakes and around the lake shores that differed by as much as 50 ppb while differences over land were usually 10 ppb or less. Through another series of sensitivity studies that varied ozone precursor emissions, it was shown that a reduction of 50% NOx or VOC would lower the 60 ppb ozone exposure by up to 50 h per month in the remote forest regions over the northern Great Lakes. The implications of these results on future climate change and air quality in the region is discussed.

  17. Historical land cover changes in the Great Lakes Region

    USGS Publications Warehouse

    Cole, K.L.; Davis, M.B.; Stearns, F.; Guntenspergen, G.; Walker, K.

    1999-01-01

    Two different methods of reconstructing historical vegetation change, drawing on General Land Office (GLO) surveys and fossil pollen deposits, are demonstrated by using data from the Great Lakes region. Both types of data are incorporated into landscape-scale analyses and presented through geographic information systems. Results from the two methods reinforce each other and allow reconstructions of past landscapes at different time scales. Changes to forests of the Great Lakes region during the last 150 years were far greater than the changes recorded over the preceding 1,000 years. Over the last 150 years, the total amount of forested land in the Great Lakes region declined by over 40%, and much of the remaining forest was converted to early successional forest types as a result of extensive logging. These results demonstrate the utility of using GLO survey data in conjunction with other data sources to reconstruct a generalized 'presettlement' condition and assess changes in landcover.

  18. Reaching Regional and Local Learners via a Great Lakes MOOC

    NASA Astrophysics Data System (ADS)

    Mooney, M. E.; Ackerman, S. A.

    2015-12-01

    The Cooperative Institute of Meteorological Satellite Studies (CIMSS) took a regional approach to climate change education in a 4-week MOOC (Massive Open On-line Course) on the Changing Weather and Climate in the Great Lakes Region launched in February 2015. Featuring a different season each week, this Great Lakes MOOC includes lectures about seasonal weather conditions, observed changes, and societal impacts of regional climate change, as well as actions with co-benefits to slow future climate change. To better connect with learners, CIMSS facilitated 21 discussion groups at public libraries around Wisconsin each week. Participants discussed climate change impacts in their communities as well as strategies to mitigate climate change. Not surprisingly, initial survey results show library participants were more committed, engaged, climate literate, and community minded. This session will share lessons learned and survey results from the Great Lakes MOOC which remains open and accessible on Coursera through February 2016 at https://www.coursera.org/course/greatlakesclimate.

  19. 77 FR 63302 - San Gabriel Valley Water Company dba, Fontana Water Company; Notice of Application Accepted for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ... Energy Regulatory Commission San Gabriel Valley Water Company dba, Fontana Water Company; Notice of.... d. Applicant: San Gabriel Valley Water Company dba, Fontana Water Company. e. Name of Project: Sandhill Water Treatment Plant In-Conduit Hydroelectric Project. f. Location: The proposed Sandhill...

  20. Conditions of formation of glacial lakes in Mt Everest region

    NASA Astrophysics Data System (ADS)

    Salerno, F.; Thakuri, S.; D'Agata, C.; Smiraglia, C.; Manfredi, E. C.; Viviano, G.; Tartari, G.

    2012-04-01

    Mount Everest (southern central Himalayas) is the region most characterized by glacial lakes in the Hindu Kush-Himalaya range and also by wide debris-covered glaciers. This study provides a complete mapping of both these water resources (October 2008). Considering that these kind of measurements are essential in recent climate change impact studies, the analysis on uncertainty of measurements is discussed with the aim of proving a reference study when lakes are delineated using remote sensing imagery. Moreover, attention is focused on the conditions of formation of lakes, the greatest evidence of climate change impact at high altitudes characterized by debris covered glaciers. To achieve this goal, an ALOS image (October 2008) with medium-high resolution (10 m) was used. A total of 29 glaciers (356.2 ±2% km2) was plotted. The total number of lakes is 624, corresponding to an overall surface area of 7.43 (±18%) km2. We examine the analysis in depth, underlining the capability of ALOS imagery to properly characterize 64% of lakes (error <15%) in terms of surface whereas, concerning glaciers, this sensor allows correctly characterizing the whole resource (error 2%). Concerning the surfaces of lakes not directly connected with glaciers (unconnected-glacial lakes), we found they are correlated with the dimension of their drainage basin, while no correlation was found with the glacier cover in the basin. Considering the evaporation/precipitation ratio at these altitudes is around 0.34 the evolution of these lakes appears to be a helpful sign for detecting the precipitation trend. Regarding the formation process of supraglacial lakes on debris-covered glaciers, the main factors which seem responsible are the low velocity and high ablation rates at the glacier terminus. Our findings confirm that the slope of the glacier where lakes are located, mainly influencing the first factor, provides the boundary condition favourable for lake formation. Otherwise the novelty of

  1. 40 CFR 81.273 - Lake County Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Lake County Intrastate Air Quality... Quality Control Regions § 81.273 Lake County Intrastate Air Quality Control Region. The Lake County... outermost boundaries of the area so delimited): In the State of California: Lake County....

  2. 40 CFR 81.273 - Lake County Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Lake County Intrastate Air Quality... Quality Control Regions § 81.273 Lake County Intrastate Air Quality Control Region. The Lake County... outermost boundaries of the area so delimited): In the State of California: Lake County....

  3. 40 CFR 81.273 - Lake County Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Lake County Intrastate Air Quality... Quality Control Regions § 81.273 Lake County Intrastate Air Quality Control Region. The Lake County... outermost boundaries of the area so delimited): In the State of California: Lake County....

  4. 40 CFR 81.273 - Lake County Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Lake County Intrastate Air Quality... Quality Control Regions § 81.273 Lake County Intrastate Air Quality Control Region. The Lake County... outermost boundaries of the area so delimited): In the State of California: Lake County....

  5. 40 CFR 81.273 - Lake County Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Lake County Intrastate Air Quality... Quality Control Regions § 81.273 Lake County Intrastate Air Quality Control Region. The Lake County... outermost boundaries of the area so delimited): In the State of California: Lake County....

  6. Solar ponds in alkaline lake and oil well regions

    SciTech Connect

    Lodhi, M.A.K.

    1996-05-01

    Solar ponds are probably the simplest technology available for useful conversion of solar energy. The basic technology is proven. Solar ponds have been shown to be technically feasible and economically viable for many applications particularly for thermal use. The electrical conversion and use of solar energy via solar ponds is still questionable in general for economic viability. By putting the untapped sources together in the South Plains region it looks promising economically both for thermal and electrical conversions and applications. There are a number of alkaline lake basins randomly scattered in the South Plains region of the USA. In that area there are thousands of crude oil producing wells which produce brine in abundance. Selection of suitable alkaline lake basins as a solar pond site and as depository sites of brine from oil wells and using of this brine and salty water from alkaline lakes makes the solar pond economically viable for both thermal and electrical demands in the area.

  7. Relations between Meteorology and Ozone in the Lake Michigan Region.

    NASA Astrophysics Data System (ADS)

    Hanna, Steven R.; Chang, Joseph C.

    1995-03-01

    The field program phase of the Lake Michigan Ozone Study (LMOS) took place during the summer of 1991. Observed ozone concentrations and weather variables have been analyzed for the Lake Michigan region and the eastern United States for four 1991 LMOS ozone episodes covering 21 days. It is found that all LMOS episodes are associated with large polluted regions with dimensions of 1000 2000 km, located on the western side of high pressure systems centered over the eastern United States. Consequently, the air coming into the LMOS region contains significant amounts of ozone, haze, and other pollutants advected along trajectories with anticyclonic curvature originating in upwind source regions from St. Louis, through the Ohio River valley, and into the northeast megalopolis. The local sources in the Gary-Chicago-Milwaukee region then add to this already polluted air mass, where concentrations are influenced by the strong stability of the boundary layer over Lake Michigan and the associated lake-land-breeze circulations. However, the magnitudes of ozone concentrations in the LMOS region are often quickly and significantly reduced by rain and by fronts, which are present in some portion of the domain during nearly all of the days that were studied. The portion of the urban ozone plume that is not influenced by rain and fronts is observed to be advected into rural areas at downwind distances of 100 200 km or more from Chicago, and often has concentrations higher than those in Chicago. Whether maximum concentrations are located on the western or the eastern shoreline of Lake Michigan depends on whether winds have an easterly or westerly component.

  8. Lakes as components in the greenhouse gas balance - regional implications as exemplified for Lake Neusiedl (Austria)

    NASA Astrophysics Data System (ADS)

    Soja, Gerhard; Kitzler, Barbara; Soja, Anna-Maria

    2013-04-01

    Inland surface waters and associated wetlands must not be neglected when global greenhouse gas emissions are balanced. Natural lakes, rivers and hydroelectric reservoirs are parts of the surface water system where outgassing of CO2 or CH4 enhances the carbon flux to the atmosphere. For lakes, the carbon emission estimates vary over several orders of magnitude, depending on the age of the lake, depth, area, volume, temperature, input of organic carbon and residence time. Nitrogen input into lakes may be caused by wet atmospheric deposition, by surface runoff from agricultural areas and by wastewater inputs into the tributaries. In most cases, denitrification of nitrate is the dominating source of N2O; only in the case of high ammonium loads and oxygen availability nitrification and subsequent denitrification to N2O and N2 play a major role. Focusing on Lake Neusiedl (Austria) as case study, this study aims at illuminating the regional role of a shallow steppe lake as greenhouse gas emitter and at analyzing the local physico-chemical conditions affecting the emission of CO2, CH4 and N2O. The uniqueness of this lake with regard to its shallowness, salinity and sediment depth required the performance of separate measurement campaigns instead of applying general lake greenhouse gas flux rates. For the period of 9 months (based on 6 observation episodes in spring, summer, and autumn), the greenhouse gas emissions of the lake consisted of about 75700 t CO2, 1006 t CH4, and 18 t N2O. Presumably because of significant sulphate concentrations in the lake water (0.3-0.4 g/l) and high pH (8.5-9) the C emissions were not dominated by CH4 but by CO2. Approximately one third of the methane and carbon dioxide emissions originated in the pelagic zone and two thirds in the reed belt whereas nitrous oxide emissions were similar in these two zones. An estimate of ebullitive emissions resulted in additional 1765 t CH4 that predominantly originated in or near the reed belt from spring

  9. Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes

    USGS Publications Warehouse

    Filstrup, Christopher T.; Wagner, Tyler; Soranno, Patricia A.; Stanley, Emily H.; Stow, Craig A.; Webster, Katherine E.; Downing, John A.

    2014-01-01

    The relationship between chlorophyll a (Chl a) and total phosphorus (TP) is a fundamental relationship in lakes that reflects multiple aspects of ecosystem function and is also used in the regulation and management of inland waters. The exact form of this relationship has substantial implications on its meaning and its use. We assembled a spatially extensive data set to examine whether nonlinear models are a better fit for Chl a—TP relationships than traditional log-linear models, whether there were regional differences in the form of the relationships, and, if so, which regional factors were related to these differences. We analyzed a data set from 2105 temperate lakes across 35 ecoregions by fitting and comparing two different nonlinear models and one log-linear model. The two nonlinear models fit the data better than the log-linear model. In addition, the parameters for the best-fitting model varied among regions: the maximum and lower Chl aasymptotes were positively and negatively related to percent regional pasture land use, respectively, and the rate at which chlorophyll increased with TP was negatively related to percent regional wetland cover. Lakes in regions with more pasture fields had higher maximum chlorophyll concentrations at high TP concentrations but lower minimum chlorophyll concentrations at low TP concentrations. Lakes in regions with less wetland cover showed a steeper Chl a—TP relationship than wetland-rich regions. Interpretation of Chl a—TP relationships depends on regional differences, and theory and management based on a monolithic relationship may be inaccurate.

  10. Wind energy resource atlas. Volume 3. Great Lakes Region

    SciTech Connect

    Paton, D.L.; Bass, A.; Smith, D.G.; Elliott, D.L.; Barchet, W.R.; George, R.L.

    1981-02-01

    The Great Lakes Region atlas assimilates six collections of wind resource data, one for the region and one for each of the five states that compose the Great Lakes region: Illinois, Indiana, Michigan, Ohio, Wisconsin. At the state level, features of the climate, topography, and wind resource are discussed in greater detail than in the regional discussion and the data locations on which the assessment is based are mapped. Variations over several time scales in the wind resource at selected stations in each state are shown on graphs of monthly average and interannual wind speed and power, and of hourly average wind speed for each season. Other graphs present speed, direction, and duration frequencies of the wind at these locations.

  11. Detection of Critical LUCC Indices and Sensitive Watershed Regions Related to Lake Algal Blooms: A Case Study of Taihu Lake

    PubMed Central

    Lin, Chen; Ma, Ronghua; Su, Zhihu; Zhu, Qing

    2015-01-01

    Taihu Lake in China has suffered from severe eutrophication over the past 20 years which is partly due to significant land use/cover change (LUCC). There is an increasing need to detect the critical watershed region that significantly affects lake water degradation, which has great significance for environmental protection. However, previous studies have obtained conflicting results because of non–uniform lake indicators and inadequate time periods. To identify the sensitive LUCC indices and buffer distance regions, three lake divisions (Meiliang Lake, Zhushan Lake and Western Coastal region) and their watershed region within the Taihu Lake basin were chosen as study sites, the algal area was used as a uniform lake quality indicator and modeled with LUCC indices over the whole time series. Results showed that wetland (WL) and landscape index such as Shannon diversity index (SHDI) appeared to be sensitive LUCC indices when the buffer distance was less than 5 km, while agricultural land (AL) and landscape fragmentation (Ci) gradually became sensitive indices as buffer distances increased to more than 5 km. For the relationship between LUCC and lake algal area, LUCC of the WC region seems to have no significant effect on lake water quality. Conversely, LUCC within ML and ZS region influenced algal area of corresponding lake divisions greatly, while the most sensitive regions were found in 3 km to 5 km, rather than the whole catchment. These results will be beneficial for the further understanding of the relationship between LUCC and lake water quality, and will provide a practical basis for the identification of critical regions for lake. PMID:25642691

  12. Detection of critical LUCC indices and sensitive watershed regions related to lake algal blooms: a case study of Taihu Lake.

    PubMed

    Lin, Chen; Ma, Ronghua; Su, Zhihu; Zhu, Qing

    2015-02-01

    Taihu Lake in China has suffered from severe eutrophication over the past 20 years which is partly due to significant land use/cover change (LUCC). There is an increasing need to detect the critical watershed region that significantly affects lake water degradation, which has great significance for environmental protection. However, previous studies have obtained conflicting results because of non-uniform lake indicators and inadequate time periods. To identify the sensitive LUCC indices and buffer distance regions, three lake divisions (Meiliang Lake, Zhushan Lake and Western Coastal region) and their watershed region within the Taihu Lake basin were chosen as study sites, the algal area was used as a uniform lake quality indicator and modeled with LUCC indices over the whole time series. Results showed that wetland (WL) and landscape index such as Shannon diversity index (SHDI) appeared to be sensitive LUCC indices when the buffer distance was less than 5 km, while agricultural land (AL) and landscape fragmentation (Ci) gradually became sensitive indices as buffer distances increased to more than 5 km. For the relationship between LUCC and lake algal area, LUCC of the WC region seems to have no significant effect on lake water quality. Conversely, LUCC within ML and ZS region influenced algal area of corresponding lake divisions greatly, while the most sensitive regions were found in 3 km to 5 km, rather than the whole catchment. These results will be beneficial for the further understanding of the relationship between LUCC and lake water quality, and will provide a practical basis for the identification of critical regions for lake. PMID:25642691

  13. Winter and Summer Views of the Salt Lake Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Magnificent views of the region surrounding Salt Lake City, Utah are captured in these winter and summer images from the Multi-angle Imaging SpectroRadiometer's vertical-viewing (nadir) camera. Salt Lake City, situated near the southeastern shore of the Great Salt Lake, is host to the 2002 Winter Olympic Games, which open Friday, February 8. Venues for five of the scheduled events are at city (indoor) locations, and five in mountain (outdoor) facilities. All ten can be found within the area contained in these images. Some of the outdoor events take place at Ogden, situated north of Salt Lake City and at Park City, located to the east.

    Salt Lake City is surrounded by mountains including the Wasatch Range to the east, and the temperature difference between the Great Salt Lake and the overlying atmosphere enhances the moisture content of winter storms. These factors, in combination with natural cloud seeding by salt crystals from the lake, are believed to result in greater snowfall in neighboring areas compared to more distant locales.

    In addition to the obvious difference in snow cover between the winter and summer views, water color changes in parts of the Great Salt Lake are apparent in these images. The distinctly different coloration between the northern and southern arms of the Great Salt Lake is the result of a rock-filled causeway built in 1953 to support a permanent railroad. The causeway has resulted in decreased circulation between the two arms and higher salinity on the northern side. The southern part of the lake includes the large Antelope Island, and at full resolution a bridge connecting it to the mainland can be discerned.

    These images are natural color views acquired on February 8, 2001 and June 16, 2001, during Terra orbits 6093 and 7957, respectively. Each image represents an area of about 220 kilometers x 285 kilometers.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth

  14. Bioremoval of heavy metals and nutrients from sewage plant by Anabaena oryzae and Cyanosarcina fontana.

    PubMed

    Fawzy, Mustafa A; Issa, Ahmed A

    2016-01-01

    The present study demonstrated the growth of two species of cyanobacteria on wastewater isolated from sewage plant in Aswan, Egypt. We evaluated their efficiency for eliminating nitrogen, phosphorus, chemical oxygen demand (COD) and heavy metals (Fe(2+), Pb(2+), Cu(2+), and Mn(2+)). The growth of Cyanosarcina fontana has supported wastewater as a growth medium than Anabaena oryzae compared to standard medium. The nutrients concentration such as COD, NO3-N and PO4-P were decreased by the growth of A. oryzae and C. fontana in the wastewater after primary settling and centrate. However, the reduction of COD was less efficient than the other nutrients. The reduction percentage of COD, NO3-N and PO4-P reached 39.3, 84.1 and 90.7% as well as 54.6, 83.1, and 89.8%, in cultures of A. oryzae and C. fontana grown in the wastewater after primary settling, respectively. The reduction amounted to 10.1, 76.8, and 63.0% by A. oryzae and 43.2, 62.1, and 74.8% by C. fontana, grown in the centrate, respectively. Cyanobacteria species have the ability to accumulate the heavy metals from the wastewater to level far than the exceeding metal level in the water. Whereas, the heavy metals biosorption performance of C. fontana was higher in accumulating Fe(2+) (93.95%), Pb(2+) (81.21%), Cu(2+) (63.9%), and Mn(2+) (48.49%) compared to A. oryzae. The biosorption ability is dependent on the nature of the adsorbent studied and the type of wastewater treated. Therefore, removal of heavy metals and nutrients by the tested algae is strongly recommended as a powerful technique for the removal of pollutants from wastewater. PMID:26457837

  15. 40 CFR 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Genesee-Finger Lakes Intrastate Air... Air Quality Control Regions § 81.128 Genesee-Finger Lakes Intrastate Air Quality Control Region. The Genesee-Finger Lakes Intrastate Air Quality Control Region (New York) consists of the territorial...

  16. 40 CFR 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Genesee-Finger Lakes Intrastate Air... Air Quality Control Regions § 81.128 Genesee-Finger Lakes Intrastate Air Quality Control Region. The Genesee-Finger Lakes Intrastate Air Quality Control Region (New York) consists of the territorial...

  17. 40 CFR 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Genesee-Finger Lakes Intrastate Air... Air Quality Control Regions § 81.128 Genesee-Finger Lakes Intrastate Air Quality Control Region. The Genesee-Finger Lakes Intrastate Air Quality Control Region (New York) consists of the territorial...

  18. 40 CFR 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Genesee-Finger Lakes Intrastate Air... Air Quality Control Regions § 81.128 Genesee-Finger Lakes Intrastate Air Quality Control Region. The Genesee-Finger Lakes Intrastate Air Quality Control Region (New York) consists of the territorial...

  19. 40 CFR 81.128 - Genesee-Finger Lakes Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Genesee-Finger Lakes Intrastate Air... Air Quality Control Regions § 81.128 Genesee-Finger Lakes Intrastate Air Quality Control Region. The Genesee-Finger Lakes Intrastate Air Quality Control Region (New York) consists of the territorial...

  20. 40 CFR 81.67 - Lake Michigan Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Brown County, Calumet County, Door County, Fond du Lac County, Green Lake County, Kewaunee County... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Lake Michigan Intrastate Air Quality... Quality Control Regions § 81.67 Lake Michigan Intrastate Air Quality Control Region. The...

  1. 40 CFR 81.67 - Lake Michigan Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Brown County, Calumet County, Door County, Fond du Lac County, Green Lake County, Kewaunee County... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Lake Michigan Intrastate Air Quality... Quality Control Regions § 81.67 Lake Michigan Intrastate Air Quality Control Region. The...

  2. 40 CFR 81.67 - Lake Michigan Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Brown County, Calumet County, Door County, Fond du Lac County, Green Lake County, Kewaunee County... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Lake Michigan Intrastate Air Quality... Quality Control Regions § 81.67 Lake Michigan Intrastate Air Quality Control Region. The...

  3. 40 CFR 81.67 - Lake Michigan Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Brown County, Calumet County, Door County, Fond du Lac County, Green Lake County, Kewaunee County... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Lake Michigan Intrastate Air Quality... Quality Control Regions § 81.67 Lake Michigan Intrastate Air Quality Control Region. The...

  4. 40 CFR 81.67 - Lake Michigan Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Brown County, Calumet County, Door County, Fond du Lac County, Green Lake County, Kewaunee County... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Lake Michigan Intrastate Air Quality... Quality Control Regions § 81.67 Lake Michigan Intrastate Air Quality Control Region. The...

  5. Use of a regional atmospheric model to simulate lake-atmosphere feedbacks associated with Pleistocene Lakes Lahontan and Bonneville

    USGS Publications Warehouse

    Hostetler, S.W.; Giorgi, F.

    1992-01-01

    A regional model of the atmosphere (version 4 of the NCAR mesoscale model, MM4) was used to assess whether lake-effect precipitation was a significant component of the late-Pleistocene hydrologic budgets of Lakes Lahontan and Bonneville. Control simulations for January and July of 1979 were made using MM4, and the Pleistocene highstand surface areas of the lakes were added to the model and the simulations repeated. In the January simulations, 18% of the moisture added to the modeled atmosphere by Lake Lahontan returned to the Lahontan basin as precipitation, while 32% of the water evaporated from Lake Bonneville fell as precipitation over the Bonneville basin. In the July simulations, 7% of the moisture added to the modeled atmosphere by Lake Lahontan returned to the Lahontan basin as precipitation, and 4% of the water evaporated from Lake Bonneville fell as precipitation over the Bonneville basin. An additonal January simulation was made with the lake surface areas set at onehalf their highstand extents (the average surface area 20 to 15 ka BP). Results from this simulation were similar to the simulation with the highstand lakes, indicating lake-effect precipitation could have been a significant component of the hyrologic budgets of the lakes before and during the highstand period. ?? 1992 Springer-Verlag.

  6. Regional pattern of snow characteristics around Antarctic Lake Vostok

    NASA Astrophysics Data System (ADS)

    Vladimirova, Diana; Ekaykin, Alexey; Popov, Sergey; Shibaev, Yuriy; Kozachek, Anna; Lipenkov, Vladimir

    2015-04-01

    Since 1998 Russian Antarctic Expedition has organized several scientific traverses in the region of subglacial Lake Vostok mainly devoted to the radar echo and seismic sounding of the glacier and water (the results have been published elsewhere). Along with the geophysical studies, a number of glaciological investigations have been carried out: snow pit digging, installation of accumulation stakes, snow sampling to study the stable water isotope content. Here we for the first time present a synthesis of these works and demonstrate a series of maps that characterize the snow density, isotope content and accumulation rate the studied region. A general tendency of the snow accumulation rate and isotope content is a significant increase from south (south-west) to north (north-east) from 35 to 23 mm w.e. per year and from -53,3 ‰ to -57,3 ‰ for delta oxygen-18 respectively, which likely reflects the continental-scale pattern, i.e., increase from inland to the coast. Deuterium excess varies from 11,7 ‰ to 16,3 ‰ is negatively correlated with the isotope content, which is typical for central Antarctica. The snow density demonstrate different pattern: higher values offshore the lake (up to 0,356 g/cm^3), and lower values within the lake's shoreline (lower limit is 0,328 g/cm^3). We suggest that this is related to the katabatic wind activity: very flat nearly horizontal surface of the glacier above the lake is not favorable for the strong winds, which leads to lower surface snow density. Superimposed on the main trend is the regional pattern, namely, curved contour lines in the middle part of the lake. We suggest that it may be related to the local anomalies of the snow drift by wind. Indeed, on the satellite images of the lake one can easily see a snowdrift stretching from the lake's western shore downwind in the middle part of the lake. The isolines of delta oxygen-18 and deuterium excess become perpendicular to each other in the north part of the lake which also

  7. Lake states regional forest resources assessments: Technical papers. Forest Service general technical report

    SciTech Connect

    Webster, H.H.; Vasievich, J.M.

    1997-07-23

    Contains 21 technical working papers prepared for the Lake States regional forest resources assessment, Lake States Forestry Alliance 1995. They represent significant contributions from many individuals and organizations and form the technical background for the Assessment.

  8. A revision of hominin fossil teeth from Fontana Ranuccio (Middle Pleistocene, Anagni, Frosinone, Italy).

    PubMed

    Rubini, Mauro; Cerroni, Vittorio; Festa, Giulia; Sardella, Raffaele; Zaio, Paola

    2014-12-01

    The Fontana Ranuccio hominin teeth (FR, Latium, Italy) are dated to the Middle Pleistocene. In previous studies these teeth were classified as two lower (left and right) second molars, one lower left central incisor and a badly worn incisor crown, the exact position of which could not be determined. In 2012 these remains were acquired by the Anthropological Service of S.B.A.L. (Italian Ministry of Culture) and for this reason re-analysed. In a thorough revision we have reassessed them both morphologically and dimensionally as two lower (left and right) first molars, one lower left lateral incisor and a possible upper left canine. The comparison with penecontemporaneous and diachronic samples shows that the Fontana Ranuccio teeth are morphologically similar to Atapuerca-Sima de los Huesos, Arago XIII and Neanderthal samples. PMID:25440134

  9. Nitrogen deposition to lakes in national parks of the western Great Lakes region: Isotopic signatures, watershed retention, and algal shifts

    NASA Astrophysics Data System (ADS)

    Hobbs, William O.; Lafrancois, Brenda Moraska; Stottlemyer, Robert; Toczydlowski, David; Engstrom, Daniel R.; Edlund, Mark B.; Almendinger, James E.; Strock, Kristin E.; VanderMeulen, David; Elias, Joan E.; Saros, Jasmine E.

    2016-03-01

    Atmospheric deposition is a primary source of reactive nitrogen (Nr) to undisturbed watersheds of the Great Lakes region of the U.S., raising concerns over whether enhanced delivery over recent decades has affected lake ecosystems. The National Atmospheric Deposition Program (NADP) has been measuring Nr deposition in this region for over 35 years. Here we explore the relationships among NADP-measured Nr deposition, nitrogen stable isotopes (δ15N) in lake sediments, and the response of algal communities in 28 lakes situated in national parks of the western Great Lakes region of the U.S. We find that 36% of the lakes preserve a sediment δ15N record that is statistically correlated with some form of Nr deposition (total dissolved inorganic N, nitrate, or ammonium). Furthermore, measured long-term (since 1982) nitrogen biogeochemistry and inferred critical nitrogen loads suggest that watershed nitrogen retention and climate strongly affect whether sediment δ15N is related to Nr deposition in lake sediment records. Measurements of algal change over the last ~ 150 years suggest that Nr deposition, in-lake nutrient cycling, and watershed inputs are important factors affecting diatom community composition, in addition to direct climatic effects on lake physical limnology. The findings suggest that bulk sediment δ15N does reflect Nr deposition in some instances. In addition, this study highlights the interactive effects of Nr deposition and climate variability.

  10. Great Lakes Biomass State and Regional Partnership (GLBSRP)

    SciTech Connect

    Kuzel, Frederic

    2009-09-01

    The Council of Great Lakes Governors administered the Great Lakes Biomass State and Regional Partnership (GLBSRP) under contract with the U. S. Department of Energy (DOE). This Partnership grew out of the existing Regional Biomass Energy Program which the Council had administered since 1983. The GLBSRP includes the States of Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin. The GLBSRP's overall goal is to facilitate the increased production and use of bioenergy and biobased products throughout the region. The GLBSRP has traditionally addressed its goals and objectives through a three-pronged approach: providing grants to the States; undertaking region-wide education, outreach and technology transfer projects; and, providing in-house management, support and information dissemination. At the direction of US Department of Energy, the primary emphasis of the GLBSRP in recent years has been education and outreach. Therefore, most activities have centered on developing educational materials, hosting workshops and conferences, and providing technical assistance. This report summarizes a selection of activities that were accomplished under this cooperative agreement.

  11. Parametric distributions of regional lake chemistry: Fitted and derived

    SciTech Connect

    Small, M.J.; Sutton, M.C.; Milke, M.W. )

    1988-02-01

    Parametric probability distribution functions are determined for regional lake chemistry in four subregions of the Eastern Lake Survey (ELS) of the US EPA National Surface Water Survey. The subregions are the Adirondacks, northeastern Minnesota, northcentral Wisconsin, and the Southern Blue Ridge Province. ANC data are fit with a three-parameter lognormal distribution, and the distributions of pH and total base cations are derived from physically based relationships estimated for each region. The parametric distribution functions provide very good representations of observed data in each area, with the exception of northcentral Wisconsin, where bimodal ANC and base cation distributions are observed, suggesting the need for a mixture of distributions. The derived distributions of pH allow for interregional comparison, with unimodal pH distributions in unacidified areas and bimodal pH distributions in regions impacted by acid deposition. Future research of regional variations in water chemistry is proposed in the context of the correlation structure of large-scale spatial variations of soil and geologic properties.

  12. Projecting Future Water Availability in the Great Lakes Megalopolis: Reconstructing Lake Michigan-Huron Lake Level and Regional Hydroclimate Using Tree Rings

    NASA Astrophysics Data System (ADS)

    Schmidt, K. R.

    2014-12-01

    The ability to accurately predict water availability in the cities surrounding Lake Michigan-Huron becomes particularly difficult when the uncertain effects of climate change, such as changes in precipitation patterns and evaporation rates, are considered. Lake level reconstructions provide useful model inputs to better predict this availability. Annual tree-ring widths have been successfully utilized in reconstructions of lake levels in the Great Lakes region via the creation of proxy datasets of temperature and precipitation that are then input into a multilinear regression model to reconstruct annual average lake level. Here, the combination of this approach with analysis of instrumental records of precipitation and stream flow input allows for a more comprehensive understanding of regional hydroclimate and improved projection of future water resource availability. Annual tree-ring widths of cores collected from four old-growth forests near southern Lake Michigan were combined with over 30 archived tree-ring width chronologies from the Great Lakes region and used to create proxy datasets of temperature and precipitation. A multilinear regression model related these proxy variables to Lake Michigan-Huron lake level and stream flow of the Saint Clair River, which flows into Lake Michigan-Huron, for the period of available instrumental record (1860-present). When possible, the available tree-ring widths were used to reconstruct these variables for years prior to the instrumental record. Timing and severity of rainfall events were also analyzed to identify spatial and temporal patterns and their variability over time. The combination of updated tree-ring width chronologies, chronologies from newly sampled sites, and instrumental records of various indicators of water availability provides novel and valuable insight into the future lake level of Lake Michigan-Huron.

  13. Do mining lakes in the Lusatian lignite mining region (Eastern Germany) affect regional precipitation patterns?

    NASA Astrophysics Data System (ADS)

    Brück, Yasemine; Pohle, Ina; Keuler, Klaus; Schaller, Eberhard; Hinz, Christoph

    2016-04-01

    Due to the flooding of former open-pit mines, Europe's largest artificial lake district is created in Eastern Germany. Between 1990 and 2006 more than 80 km² of new lakes have already been formed. These large-scale land cover changes may impact regional meteorological characteristics, therefore it is of interest, whether effects of the mining lakes can already be observed. We especially focus on whether the evaporation from the mining pit lakes leads to a higher precipitation on their lee side. To detect changes in the precipitation patterns, we analysed daily precipitation data (1980-2014) of 25 stations in an area of 10 000 km² widely around the lake district. Under the assumption that the influences of the lakes should be detectable either directly as trends in the observed data or as a deviation from a general measure for precipitation we combined statistical tests and principal component analysis (PCA). We applied pre-whitening Mann-Kendall tests to detect precipitation trends and Mann-Whitney tests to detect differences between split samples (before and after the flooding of most of the lakes). The PCA was applied based on the correlation matrix of daily precipitation at the different stations. As the daily precipitation can sufficiently be explained by the first five principal components, the recombination of these five principal components was used as a general measure of precipitation in the region. By regression trees (random forests) a relationship between the eigenvectors of the first five principal components and physiogeographic characteristics of the stations (e.g. altitude) was shown. Both the observed data and the deviations between the measurements and the recombination of the first five principal components showed divergent trends with high spatial variability and also interannual variability, but a pattern consistent with the lee side of the lake could not be detected. Therefore, it has been demonstrated that the emerging lakes had no

  14. Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: Hydroclimatic implications

    NASA Astrophysics Data System (ADS)

    Watras, C. J.; Read, J. S.; Holman, K. D.; Liu, Z.; Song, Y.-Y.; Watras, A. J.; Morgan, S.; Stanley, E. H.

    2014-01-01

    We report a unique hydrologic time series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13 years) is remarkably consistent among small seepage lakes, groundwater tables, and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P - E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the midlatitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by an ~12 years downward trend beginning in 1998. Record low water levels region wide may mark the onset of a new hydroclimatic regime.

  15. Integrating a 1D Thermal Lake Model into a Global and Regional Climate Model: Model Evaluation and Regional Climate Simulation

    NASA Astrophysics Data System (ADS)

    Subin, Z. M.; Riley, W. J.

    2009-12-01

    Compared to solid ground, lakes tend to have decreased albedo, increased ground heat conductance, and increased effective ground heat capacity. These features alter local surface fluxes compared to nearby vegetation, which in turn alter the climate of the nearby atmosphere and surrounding land areas. Interest in feedbacks between lake behavior and climate change provides motivation for including lakes in global climate models, as does the desire to do effective regional downscaling of climate model predictions over regions with large lake area fraction, like the Great Lakes region. Finally, the initiation, warming, and expansion of Arctic thermokarst lakes could provide an important geophysical and biogeochemical feedback to climate warming. The Community Land Model (CLM) 3.5 currently uses a 1D Hostetler lake scheme. We have updated this model to improve the characterization of surface fluxes, eddy diffusivity, and convective mixing. We also link the lake model with the full snow physics found over other land surface types (including 5 snow layers, aerosol deposition, partial transparency of snow layers, and snow aging), add phase change & ice physics to the lake model, and include soil layers beneath lakes. These soil layers will be an important component of future thermokarst lake modeling, as thermokarst lakes tend to form regions of unfrozen soil (talik) beneath them that become active sites for anaerobic decomposition of pre-modern peat. We have also integrated the updated lake model into a modified version of the Weather Research and Forecasting (WRF) Model 3.0. We will present comparisons between predicted and observed thermal conditions, snow and ice depths, and surface energy fluxes at several lake sites, using local meteorological forcing or integrated regional atmospheric coupling. The thermal predictions are generally reasonable and show a marked improvement from runs performed with the baseline CLM 3.5 version of the lake model. Over Sparkling Lake

  16. Carbon Cycling in Lake Superior: Impact on Upper Midwest Regional Carbon Balance

    NASA Astrophysics Data System (ADS)

    Desai, A. R.; McKinley, G. A.; Urban, N. R.; Wu, C. H.

    2007-12-01

    Understanding the regional surface-atmosphere exchange of carbon dioxide of inland water bodies is important for accurately quantifying and scaling regional continental carbon budgets. It is widely recognized that many lakes are net sources of CO2 to the atmosphere. However, our ability to predict CO2 fluxes from any particular lake remain rather limited. In a landscape rich in lakes and wetlands such as the upper Midwest Great Lakes region, assumptions that CO2 fluxes from lakes are negligible seem disingenuous and bear potential for adding error to estimates of regional carbon flux. The Laurentian Great Lakes cover 25 percent of the land area of the 8 Great Lakes states, and CO2 emission and seasonal cycling from them may be comparable to local terrestrial ecosystems. CO2 fluxes from Lake Superior are of particular interest because they may directly impact CO2 observations at nearby AmeriFlux towers. DOC inputs to lakes are considered a major controlling factor on lake CO2 concentrations. Recent findings estimated the turnover time of dissolved organic carbon (DOC) in Lake Superior to be about 8 years. We have collected lake water samples, analyzed above lake CO2 concentrations, and started coupling an ecosystem-carbon module to an existing high resolution hydrodynamic model of Lake Superior in an attempt to estimate these fluxes and their spatial and temporal variability. Here we present initial results from this effort and place these reseults in context with regional terrestrial CO2 fluxes. Municipal water intakes were analyzed for water properties. The measured values for alkalinity and pH in the Lake Superior samples were within the range previously reported for the lake. Additionally, CO2 concentrations measured above Lake Superior were shown to be elevated above what would be expected on land, with a gradient of increasing concentrations with increasing wind travel distance from shore. Both of these initial measurements suggest that Lake Superior can be a

  17. Rehabilitation of lake trout in the Apostle Islands region of Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; King, George R.

    1968-01-01

    Marked success of rehabilitation of lake trout in Lake Superior has been due principally to the control of the sea lamprey and closure of the lake trout fishery in 1962 and large-scale plantings of yearling lake trout in 1959-66. After the sea lamprey became established in the late 1940s, spawning stocks of lake trout began to decrease and were almost nonexistent by 1960-61. After control of the sea lamprey and closure of the commercial fishery for lake trout in 1962, the abundance of spawning stocks began to rise and reached the highest levels on record in 1964-66. Successful spawning in 1964 and 1965 was demonstrated by catches of age-0 lake trout in 1965 and 1966, the first evidence of natural reproduction since 1959. Plantings of hatchery-reared lake trout in Wisconsin waters of Lake Superior began in 1952. The percentage of hatchery-reared fish in catches of juvenile lake trout increased almost steadily from 1953 to 1965 (when nearly all were of hatchery origin). The abundance of juvenile fish increased from 1959 to 1962 and remained nearly constant in 1962-66. The success of lake trout plantings was highest in 1959-61 but generally declined after 1961; the success of the plantings was inversely related to the abundance of older lake trout. Annual increments of growth of hatchery-reared lake trout varied from 1.1 to 5.0 inches after planting. The average lengths of fish of identical age-groups varied according to gear of capture, depth of water, and season. More than 65% of the season's growth of age-III lake trout took place after September. The findings indicate that the present rate of stocking lake trout may be higher than necessary to maintain optimum abundance.

  18. Birth Outcomes across Three Rural-Urban Typologies in the Finger Lakes Region of New York

    ERIC Educational Resources Information Center

    Strutz, Kelly L.; Dozier, Ann M.; van Wijngaarden, Edwin; Glantz, J. Christopher

    2012-01-01

    Purpose: The study is a descriptive, population-based analysis of birth outcomes in the New York State Finger Lakes region designed to determine whether perinatal outcomes differed across 3 rural typologies. Methods: Hospital birth data for the Finger Lakes region from 2006 to 2007 were used to identify births classified as low birthweight (LBW),…

  19. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

    PubMed Central

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-01-01

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

  20. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

    PubMed

    Lin, Chen; Ma, Ronghua; He, Bin

    2016-01-01

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

  1. Evaluation of Regional Climate Simulations over the Great Lakes Region Driven by Three Global Data Sets

    SciTech Connect

    Zhong, Shiyuan; Li, Xiuping; Bian, Xindi; Heilman, Warren E.; Leung, Lai-Yung R.; Gustafson, William I.

    2012-06-27

    The performance of regional climate simulations is evaluated for the Great Lakes region. Three 10-year (1990–1999) current-climate simulations are performed using the MM5 regional climate model (RCM) with 36-km horizontal resolution. The simulations employed identical configuration and physical parameterizations, but different lateral boundary conditions and sea-surface temperatures derived from the NCEP Global Reanalysis and output from the CCSM3 and GISS general circulation models (GCMs). The simulation results are compared to the North American Regional Reanalysis (NARR). The three RCM simulations appeared to be more accurate in winter and least accurate in summer, and more accurate aloft than near the surface. The reanalysis-constrained simulation adequately captured the spatial distribution and seasonal cycle of the observed surface-air temperature and precipitation, but it produced consistently across all seasons a cold bias that is generally larger over the lakes than over land and a wet bias due to an overestimation of nonconvective precipitation. The simulated seasonal cycle of moisture–flux convergence over the region was in very good agreement with NARR. The two GCM-driven runs adequately simulated the spatial and seasonal variation of temperature, but overestimated cold-season precipitation and underestimated summer precipitation, reversing the observed annual precipitation cycle. The GISS-driven run failed to simulate the prevailing low-level flow and moisture convergence patterns. All three RCM simulations successfully captured the impact of the Great Lakes on the region's climate, especially on winter precipitation, a significant improvement over coarse-resolution GCM simulations over the region.

  2. The Oligochaeta (Annelida, Clitellata) of the St. Lawrence Great Lakes region: An update

    USGS Publications Warehouse

    Spencer, Douglas R.; Hudson, Patrick L.

    2003-01-01

    An updated oligochaete species list for the Great Lakes region is provided. The list was developed through the reexamination of the taxa reported in a previous report in 1980, addition of new taxa or records collected from the region since 1980, and an update of taxonomy commensurate with systematic and nomenclatural changes over the intervening years since the last review. The authors found 74 papers mentioning Great Lakes oligochaete species. The majority of these papers were published in the 1980s. The literature review and additional collections resulted in 15 species being added to the previous list. Nine taxa were removed from the previous list due to misidentification, synonymies, level of identification, or inability to confirm the identity. Based on this review, 101 species of Oligochaeta are now known from the St. Lawrence Great Lakes watershed. Of these, 95 species are known from the St. Lawrence Great Lakes proper, with an additional 6 species recorded from the inland waters of the watershed. The greatest diversity of oligochaete species was found in the inland waters of the region (81) followed by Lake Huron (72), Lake Ontario (65), Lake Erie (64), Lake Superior (63), Lake Michigan (62), St. Marys River (60), Niagara River (49), Saginaw Bay (44), St. Clair River (37), Lake St. Clair (36), St. Lawrence River (27), and the Detroit River (21). Three species are suspected of being introduced, Branchiura sowerbyi, Gianius aquaedulcisand Ripistes parasita, and two are believed to be endemic, Thalassodrilus hallae andTeneridrilus flexus.

  3. How much acidification has occurred in Adirondack region lakes (New York, USA) since preindustrial times

    SciTech Connect

    Cumming, B.F.; Smol, J.P.; Kingston, J.C.; Charles, D.F.; Birks, H.J.B.

    1992-01-01

    Preindustrial and present-day lake water pH, acid neutralizing capacity (ANC), total monomeric aluminum Al(sub m), and dissolved organic carbon (DOC) were inferred from the species composition of diatom and chrysophyte microfossils in the tops (present-day inferences) and bottoms (pre-1850 inferences) of sediment cores collected from a statistically selected set of Adirondack lakes. Results from the study lakes were extrapolated to a predefined target population of 675 low-alkalinity Adirondack region lakes. Estimates of preindustrial to present-day changes in lake water chemistry show that approximately 25-35% of the target population has acidified. The magnitude of acidification was greatest in the low-alkalinity lakes of the southwestern Adirondacks, an area with little geological ability to neutralize acidic deposition and receives the highest annual average rainfall in the region. The authors estimate that approximately 80% of the target population lakes with present-day measured pH = or < 5.2 and 30-45% of lakes with pH between 5.2 and 6.0 have undergone large declines in pH and ANC, and concomitant increases in Al(sub m). Estimated changes in (DOC) were small and show no consistent pattern in the acidified lakes. The study provides the first statistically based regional evaluation of the extent of lake acidification in the Adirondacks.

  4. "The Effect of Alternative Representations of Lake Temperatures and Ice on WRF Regional Climate Simulations"

    EPA Science Inventory

    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 Weathe...

  5. Ecosystem scale VOC exchange measurements at Bosco Fontana (IT) and Hyytiälä (FI)

    NASA Astrophysics Data System (ADS)

    Schallhart, S.; Rantala, P.; Taipale, R.; Nemitz, E.; Tillmann, R.; Mentel, T. F.; Ruuskanen, T.; Rinne, J.

    2013-12-01

    The ozone production and destruction mechanisms in the troposphere depend on the abundance of NOx and volatile organic compounds (VOCs). As the latter originate not only from human activities, but to a large extent from vegetation it is important to quantify these biogenic sources as well. The VOC-fluxes were measured in Bosco Fontana forest as a part of an intensive measurement campaign of the Eclaire project, which investigates how climate change alters the threat of air pollution. Measurements were carried out at the Nature Reserve 'Bosco della Fontana' in the Po valley, Italy. The area of the forest is 198 ha and the dominanting tree species are Quercus robur (English oak), Quercus cerris (Turkey oak) and Carpinus betulus (hornbeam). The fluxes were measured on at a height of 32 metres using the eddy covariance method. A PTR-TOF (Ionicon Analytik, Austria) measured volatile organic compounds up to a mass of 300 atomic mass units. The instrument is capable of recording full spectra of VOCs in real-time with a resolution of 10 Hz. In addition to the mass spectrometer a 3D Anemometer was placed next to the inlet. Results will be presented and compared with disjunct eddy covariance measurements (Taipale et al. 2011) from a Pinus sylvestris (Scots Pine) dominated forest in Hyytiälä, Finland. The two forests are characterized by a different emission profile; the Bosco Fontana forest emits large amounts of isoprene, whereas the terpenoid emissions from Hyytiälä forest are dominated by monoterpenes. The magnitude of the emissions differs as emission from Bosco Fontana is much higher. The monoterpene emission from Bosco Fontana is likely to follow different dynamics than that from Hyytiälä as it correlates well with the radiation. This leads to the conclusion, that monoterpenes are released right after they are produced (de novo). In Hyytiälä the emissions are light and temperature dependent, which is caused by de novo and storage emissions. Pines have large

  6. Ecohydrological research in the Poyang lake region in China

    NASA Astrophysics Data System (ADS)

    Schmalz, Britta; Fohrer, Nicola; Jähnig, Sonja; Cai, Qinghua; Bieger, Katrin

    2010-05-01

    The presented concept of the DFG project "Integrated modelling of the response of aquatic ecosystems to land use and climate change in the Poyang lake region, China" is part of the NSFC/DFG-Joint funding programme "Land Use and Water Resources Management under Changing Environmental Conditions". The aim of our project is the development of an integrated modelling methodology to assess the impact of fast environmental changes on aquatic ecosystems in the example catchment of the Changjiang (6260 km²) in the Poyang lake area (China). Joint measurement and sampling campaigns will be the basis for integrating three different models: we aim to model a dynamic DPSI(R)-system, for the first time coupling the models SWAT (catchment processes), HEC-RAS (in-stream processes) and MAXENT/BIOMOD (biological responses). Major drivers (climate, land use, channel alteration) are model input data, while the main pressures on the ecosystem (water balance, nutrients, sedimentation) are defined and represented in the model algorithms of SWAT and HEC-RAS. Based on the multiple pressures, we aim to dynamically assess the changes of the state of habitat parameters (e.g. flow, depth, substrate) in the model output. Finally, the impact of the state on the aquatic eco-systems will be evaluated by analysing shift of distribution ranges modelled by MAXENT/BIOMOD and changes in biodiversity or ecosystem health indicators of benthic invertebrates, an important group in freshwater ecosystems. Joint scenario runs considering climate or land use changes will particularly enhance understanding (1) how landscape processes and nutrient cycles interact with ecohydrological and aquatic system properties and (2) how the impact of land use, climate and hydromorphological change on aquatic ecosystem properties can be assessed.

  7. Seismic reflection study of recessional moraines beneath Lake Superior and their relationship to regional deglaciation

    USGS Publications Warehouse

    Landmesser, C.W.; Johnson, T.C.; Wold, R.J.

    1982-01-01

    Approximately 8000 km of continuous seismic reflection profiles throughout Lake Superior were examined for evidence of recessional moraines and other ice-margin deposits associated with the retreat of late Wisconsin ice. These features are correlated with the record of glacial-lake evolution in western Lake Superior. An offlapping sequence of glacial and glacial-lacustrine dediments overlying bedrock is recognized in west-central Lake Superior that is progressively younger to the northeast. The sequence underlies more recent glaical-lacustrine and postglacial sediments. Four facies are recognized on the basis of geomorphologic and acoustic properties and are interpreted to represent a southwest-to-northeast assemblage of: proglacial stratified drift (facies A), drift in major end moraines (facies B), till deposited as glacial retreat resumed, or possibly late-stage ablation till (facies C), and basal till (facies D). The prominent moraines of facies B are unusually thick and are believed to mark the ice-margin shorelines of successive major proglacial lakes that formerly occupied parts of western Lake Superior. The moraines are tentatively correlated with Glacial Lake Duluth (unit 1), Glacial Lake Washburn (unit 2), and Glacial Lake Beaver Bay (unit 3), the most prominent of lakes drained via the progressively lower outlets via the Moose Lake/ Brule-St. Croix Rivers, the Huron Mountains, and the Au Train-Whitefish regions, respectively. ?? 1982.

  8. Seismic reflection study of recessional moraines beneath Lake Superior and their relationship to regional deglaciation*1

    NASA Astrophysics Data System (ADS)

    Landmesser, C. W.; Johnson, T. C.; Wold, R. J.

    1982-03-01

    Approximately 8000 km of continuous seismic reflection profiles throughout Lake Superior were examined for evidence of recessional moraines and other ice-margin deposits associated with the retreat of late Wisconsin ice. These features are correlated with the record of glacial-lake evolution in western Lake Superior. An offlapping sequence of glacial and glacial-lacustrine dediments overlying bedrock is recognized in west-central Lake Superior that is progressively younger to the northeast. The sequence underlies more recent glaical-lacustrine and postglacial sediments. Four facies are recognized on the basis of geomorphologic and acoustic properties and are interpreted to represent a southwest-to-northeast assemblage of: proglacial stratified drift (facies A), drift in major end moraines (facies B), till deposited as glacial retreat resumed, or possibly late-stage ablation till (facies C), and basal till (facies D). The prominent moraines of facies B are unusually thick and are believed to mark the ice-margin shorelines of successive major proglacial lakes that formerly occupied parts of western Lake Superior. The moraines are tentatively correlated with Glacial Lake Duluth (unit 1), Glacial Lake Washburn (unit 2), and Glacial Lake Beaver Bay (unit 3), the most prominent of lakes drained via the progressively lower outlets via the Moose Lake/ Brule-St. Croix Rivers, the Huron Mountains, and the Au Train-Whitefish regions, respectively.

  9. Sensitivity of lake ice regimes to climate change in the Nordic region

    NASA Astrophysics Data System (ADS)

    Gebre, S.; Boissy, T.; Alfredsen, K.

    2014-08-01

    A one-dimensional process-based multi-year lake ice model, MyLake, was used to simulate lake ice phenology and annual maximum lake ice thickness for the Nordic region comprising Fennoscandia and the Baltic countries. The model was first tested and validated using observational meteorological forcing on a candidate lake (Lake Atnsjøen) and using downscaled ERA-40 reanalysis data set. To simulate ice conditions for the contemporary period of 1961-2000, the model was driven by gridded meteorological forcings from ERA-40 global reanalysis data downscaled to a 25 km resolution using the Rossby Centre Regional Climate Model (RCA). The model was then forced with two future climate scenarios from the RCA driven by two different general circulation models (GCMs) based on the Special Report on Emissions Scenarios (SRES) A1B. The two climate scenarios correspond to two future time periods namely the 2050s (2041-2070) and the 2080s (2071-2100). To take into account the influence of lake morphometry, simulations were carried out for four different hypothetical lake depths (5 m, 10 m, 20 m, 40 m) placed at each of the 3708 grid cells. Based on a comparison of the mean predictions in the future 30-year periods with the control (1961-1990) period, ice cover durations in the region will be shortened by 1 to 11 weeks in 2041-2070, and 3 to 14 weeks in 2071-2100. Annual maximum lake ice thickness, on the other hand, will be reduced by a margin of up to 60 cm by 2041-2070 and up to 70 cm by 2071-2100. The simulated changes in lake ice characteristics revealed that the changes are less dependent on lake depths though there are slight differences. The results of this study provide a regional perspective of anticipated changes in lake ice regimes due to climate warming across the study area by the middle and end of this century.

  10. Sensitivity of lake ice regimes to climate change in the nordic region

    NASA Astrophysics Data System (ADS)

    Gebre, S.; Boissy, T.; Alfredsen, K.

    2013-03-01

    A one-dimensional process-based multi-year lake ice model, MyLake, was used to simulate lake ice phenology and annual maximum lake ice thickness for the Nordic region comprising Fennoscandia and the Baltic countries. The model was first tested and validated using observational meteorological forcing on a candidate lake (Lake Atnsjøen) and using downscaled ERA-40 reanalysis data set. To simulate ice conditions for the contemporary period of 1961-2000, the model was driven by gridded meteorological forcings from ERA-40 global reanalysis data downscaled to a 25 km resolution using the Rossby Center Regional Climate Model (RCA). The model was then forced with two future climate scenarios from the RCA driven by two different GCMs based on the SRES A1B emissions scenario. The two climate scenarios correspond to two future time periods namely the 2050s (2041-2070) and the 2080s (2071-2100). To take into account the influence of lake morphometry, simulations were carried out for four different hypothetical lake depths (5 m, 10 m, 20 m, 40 m) placed at each of the 3708 grid cells. Based on a comparison of the mean predictions in the future 30 yr periods with the control (1961-1990) period, ice cover durations in the region will be shortened by 1 to 11 weeks in 2041-2070, and 3 to 14 weeks in 2071-2100. Annual maximum lake ice thickness, on the other hand, will be reduced by a margin of up to 60 cm by 2041-2070 and up to 70 cm by 2071-2100. The simulated changes in lake ice characteristics revealed that the changes are less dependent on lake depths though there are slight differences. The results of this study provide a~regional perspective of anticipated changes in lake ice regimes due to climate warming across the study area by the middle and end of this century.

  11. 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...

  12. REGIONAL SUSCEPTIBILITY OF NORTHEAST LAKES TO ZEBRA MUSSEL INVASION

    EPA Science Inventory

    The rapid spread of the exotic zebra mussel (Dreissena polymorpha) concerns aquatic resource managers in the United States and Canada. ince 1990 it has been spreading from the Great Lakes into the Northeast. he primary goal of this study is to provide lake resource managers in th...

  13. [Biodiversity of halophilic archaea isolated from two salt lakes in Xin-Jiang region of China].

    PubMed

    Cui, Heng-Lin; Yang, Yong; Dilbr, Tohty; Zhou, Pei-Jin; Liu, Shuang-Jiang

    2006-04-01

    There are more than 1000 salt lakes situated in northern and western regions of China and 790 of these salt lakes are in Xinjiang Uigur Autonomous Region and Qinghai, Tibet, Inner Mongolia. To better understand halophilic archaeal diversity of salt lakes in Xinjiang, water and sediment samples were collected from two salt lakes, namely Aibi salt lake and Aiding salt lake, and the halophilic archaeal diversity of these samples was determined. Totally eighty-six halophilic archeal strains, of which 56 isolated from Aibi salt lake and 30 isolated from Aiding salt lake, were isolated respectively using CM agar medium. All the strains were subjected to 16S rRNA gene sequencing analysis. Similarity analysis based on 16S rRNA gene sequences of all these strains indicated that the isolates from Aibi salt lake belong to 11 different species of genera Haloarcula, Halobacterium, Halorubrum, Haloterrigena, Natrinema and Natronorubrum, and that the isolates from Aiding salt lake belong to 8 different species of genera Haloarcula, Halobiforma, Halorubrum, Haloterrigena, Natrinema. Among the 86 strains, members of Natronorubrum Natrinema, Halorubrum and Haloterrigena, are dominant groups in Aibi salt lake. However, the dominant group in Aibi salt lake are the members of Natrinema, Halorubrum and Haloterrigena. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains ABH13, ABH 14, ABH 15, ABH 18, ABH 31 and ABH 33 may represent a novel species of Natronorubrum; ABH12, ABH32 and AD30 two novel species of Halorubrum; ABH17 and ABH25, ABH51, ABH52, ABH56 two novel species of Haloterrigena respectively; strain ABH19 a novel species of Haloarcula; strain ABHO7 a novel species of Halobacterium. The Shannon-Wiener's index of Aibi salt lake is 1.899, the same index of Aiding salt lake is 1.317, which indicated that the biodiversity of halophilic archaea from Aibi salt lake was slightly higher than that of Aiding salt lake. Different characteristics in pH of salt

  14. The mesoproterozoic midcontinent rift system, Lake Superior region, USA

    USGS Publications Warehouse

    Ojakangas, R.W.; Morey, G.B.; Green, J.C.

    2001-01-01

    Exposures in the Lake Superior region, and associated geophysical evidence, show that a 2000 km-long rift system developed within the North American craton ??? 1109-1087 Ma, the age span of the most of the volcanic rocks. This system is characterized by immense volumes of mafic igneous rocks, mostly subaerial plateau basalts, generated in two major pulses largely by a hot mantle plume. A new ocean basin was nearly formed before rifting ceased, perhaps due to the remote effect of the Grenville continental collision to the east. Broad sagging/subsidence, combined with a system of axial half-grabens separated along the length of the rift by accommodation zones, provided conditions for the accumulation of as much as 20 km of volcanic rocks and as much as 10 km of post-rift clastic sediments, both along the rift axis and in basins flanking a central, post-volcanic horst. Pre-rift mature, quartzose sandstones imply little or no uplift prior to the onset of rift volcanism. Early post-rift red-bed sediments consist almost entirely of intrabasinally derived volcanic sediment deposited in alluvial fan to fluvial settings; the exception is one gray to black carbon-bearing lacustrine(?) unit. This early sedimentation phase was followed by broad crustal sagging and deposition of progressively more mature red-bed, fluvial sediments with an extra-basinal provenance. ?? 2001 Elsevier Science B.V. All rights reserved.

  15. The Mesoproterozoic Midcontinent Rift System, Lake Superior Region, USA

    NASA Astrophysics Data System (ADS)

    Ojakangas, R. W.; Morey, G. B.; Green, J. C.

    2001-06-01

    Exposures in the Lake Superior region, and associated geophysical evidence, show that a 2000 km-long rift system developed within the North American craton ∽1109-1087 Ma, the age span of most of the volcanic rocks. This system is characterized by immense volumes of mafic igneous rocks, mostly subaerial plateau basalts, generated in two major pulses largely by a hot mantle plume. A new ocean basin was nearly formed before rifting ceased, perhaps due to the remote effect of the Grenville continental collision to the east. Broad sagging/subsidence, combined with a system of axial half-grabens separated along the length of the rift by accommodation zones, provided conditions for the accumulation of as much as 20 km of volcanic rocks and as much as 10 km of post-rift clastic sediments, both along the rift axis and in basins flanking a central, post-volcanic horst. Pre-rift mature, quartzose sandstones imply little or no uplift prior to the onset of rift volcanism. Early post-rift red-bed sediments consist almost entirely of intrabasinally derived volcanic sediment deposited in alluvial fan to fluvial settings; the exception is one gray to black carbon-bearing lacustrine(?) unit. This early sedimentation phase was followed by broad crustal sagging and deposition of progressively more mature red-bed, fluvial sediments with an extra-basinal provenance.

  16. A STUDY OF HIGHER EDUCATION POSSIBILITIES FOR THE ADIRONDACK LAKES REGION, NEW YORK.

    ERIC Educational Resources Information Center

    HARRIS, NORMAN C.; RUSSEL, JOHN H.

    SEVERAL PROPOSALS FOR COMMUNITY COLLEGES ARE DISCUSSED. FACTORS ARE PRESENTED WHICH RULE OUT A LOCAL COMMUNITY COLLEGE FOR THE ADIRONDACK LAKES REGION AND THE ESTABLISHMENT OF A BRANCH OF THE CANTON AGRICULTURAL-TECHNICAL COLLEGE IN THE LAKES AREA. CONSIDERATION SHOULD BE GIVEN, THOUGH, TO THE ESTABLISHMENT OF A COMMUNITY COLLEGE IN OR NEAR…

  17. ANALYSIS OF MERCURY IN VERMONT AND NEW HAMPSHIRE LAKES: EVALUATION OF THE REGIONAL MERCURY CYCLING MODEL

    EPA Science Inventory

    An evaluation of the Regional Mercury Cycling Model (R-MCM, a steady-state fate and transport model used to simulate mercury concentrations in lakes) is presented based on its application to a series of 91 lakes in Vermont and New Hampshire. Visual and statistical analyses are pr...

  18. ASTER measurement of supraglacial lakes in the Mount Everest region of the Himalaya

    USGS Publications Warehouse

    Wessels, R.L.; Kargel, J.S.; Kieffer, H.H.

    2002-01-01

    We demonstrate an application of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images to detect and monitor supraglacial lakes on glaciers in the Mount Everest region in Tibet (Xizang) and Nepal. ASTER offers powerful capabilities to monitor supraglacial lakes in terms of (1) surface area, growth and disappearance (spatial resolution = 15 m), (2) turbidity (15 m resolution), and (3) temperature (90 m resolution). Preliminary results show an overall similarity of supraglacial lakes on three glaciers. Lakes have widely varying turbidity as indicated by color in visible/near-infrared bands 1-3, the largest lakes being bright blue (highly turbid), cold (near 0??C) and hydrautically connected with other lakes and supraglacial streams, while small lakes are mostly dark blue (relatively clear water), warmer (>4??C), and appear hydrautically isolated. High levels of turbidity in supraglacial lakes indicate high rates of meltwater input from streams or erosion of ice cliffs, and thus are an indirect measure relating to the activity and hydraulic integration of the lake with respect to other lakes and streams in the glacier.

  19. Regional climate signal modified by local factors - multi core study records (Lake Czechowskie region, N Poland)

    NASA Astrophysics Data System (ADS)

    Zawiska, Izabela; Rzodkiewicz, Monika; Noryśkiewicz, Agnieszka; Kramkowski, Mateusz; Obremska, Milena; Ott, Florian; Plessen, Birgit; Tjallingii, Rik; Słowiński, Michał; Błaszkiewicz, Mirosław; Brauer, Achim

    2016-04-01

    Lake sediments can be utilized as valuable paleoclimate and environmental archives as they contain information of past changes. Multi-proxy analyses of sedimentary compartments (e.g. pollen, diatoms, Cladocera) reveal those changes. However, to decipher the spatial variability of past climate changes and to define the proxies suited for local and regional scale reconstructions archive comparisons are needed. Here we present a detailed multi-proxy study from four different sediment cores covering the Younger Dryas cold period from the Lake Czechowskie region (N Poland). Three cores are located along a transect in the Lake Czechowskie basin from its deepest point towards a former lake bay close to today's shoreline. The fourth lacustrine sediment core was retrieved from the Trzechowskie paleolake, app. 1 km W from Lake Czechowskie. The dataset comprises information from pollen (AP, NAP, Juniperus, Betula-tree, Pinus silvestris), diatom (planktonic/benthic index, diatom valve concentration, dominant species), Cladocera (planktonic/benthic index, dominant species, number of Cladocera species, total sum of specimens) and geochemical (TOC and CaCO3 content, mineral matter, titanium) analyses. At the beginning of the Younger Dryas the AP pollen share decreased and NAP and Juniperus pollen increased in all studied locations. The mineral matter and titanium record showed higher values in two cores taken from the deepest parts of Lake Czechowskie and the core from Trzechowskie paleolake while in the core located at the marginal part of the lake it was already high in Allerød and it did not change much in Younger Dryas. The Cladocera based indexes: total sum of specimens and number of species decreased at the beginning of YD but on the contrary the Cladocera species composition changes were site-specific. The diatoms valve concentration index significantly lowered in core from the deep location while on the contrary increased in core from paleolake Trzechowskie. Our results

  20. Integrated Digital Survey of the "FONTANA RUSTICA" in the Gardens of the Quirinale.

    NASA Astrophysics Data System (ADS)

    Paris, L.; Troiano, W.

    2013-07-01

    The paper illustrates the results of a research on integrated digital survey of the "Fontana Rustica" in the gardens of the Quirinale, artifact somewhat atypical for its particular organical configuration, and whose history is still to be discovered. The activity is performed by Critevat, interdepartmental research center in Rieti, within of the scientific collaboration with the Office for the conservation of artistic heritage of the Quirinale Palace. The integrated digital survey in recent years has had a strong impulse thanks to the technological development of the shape acquisition instruments. The research has analyzed the problems of interaction and integration of digital data obtainable using the latest digital technologies such as 3D laser-scanner and digital photogrammetry. A further level of research has focused on the possibility of management of 3D models in relation to data obtained by instruments and methods of investigation of different scientific culture such as seismic transmission tomography and thermografy.

  1. Titan's North Polar Region: Lake Distribution, Statistics, and Implied Methane Hydrology from Cassini SAR

    NASA Astrophysics Data System (ADS)

    Hayes, Alexander; Aharonson, O.; Lewis, K.; Mitchell, K.; Lunine, J.; Lorenz, R. D.; Wall, S.; Mitri, G.; Elachi, C.; Cassini RADAR Team

    2007-10-01

    Recent observations of Titan's Surface from Cassini's Synthetic Aperture Radar (SAR) have revealed quasi-circular to complex features which are interpreted as liquid hydrocarbon lakes (Stofan et al., 2007). We use the global distribution of lake features to investigate methane transport in Titan's hydrologic cycle, which includes atmospheric, surface, and sub-surface interaction. Specifically, the latitudinal and longitudinal division of hydrocarbon lakes combined with derived topographic information is used to model subsurface transport and place limitations on the properties of an isotropic porous regolith. Our analysis of the dataset, which covers 22% of the surface, has led to the identification of multiple lake morphologies which are correlated across the polar region. Radar dark lake features are limited to latitudes above 65°N and vary in size from the limits of observation (a few km2) to more than 100,000 km2. Granular and sub-granular lake features, which are distinguished by increased radar backscatter relative to their surroundings as compared to dark lakes, can be found as low as 55°N. Sub-granular lake features are inferred to be empty basins while granular lake features are interpreted as transitional between dark and sub-granular. The orientation, size, and statistical correlations between dark, granular, and sub-granular lake features provide constraints on precipitation conditions and the importance of subsurface transport. Using preliminary porous media properties inferred from Huygens probe results at 10°S, timescales for flow between observed dark and empty lakes are calculated by solving the groundwater flow equation. Derived lake equilibration timescales are compared to the time between collocated SAR observations in order to place limitations on the permeability of an isotropic porous regolith. For permeabilities of 10-5cm2, equilibrium timescales are found to be in the 10's of years and are similar to Titan's seasonal cycles and lake

  2. Volcano and earthquake hazards in the Crater Lake region, Oregon

    USGS Publications Warehouse

    Bacon, Charles R.; Mastin, Larry G.; Scott, Kevin M.; Nathenson, Manuel

    1997-01-01

    Crater Lake lies in a basin, or caldera, formed by collapse of the Cascade volcano known as Mount Mazama during a violent, climactic eruption about 7,700 years ago. This event dramatically changed the character of the volcano so that many potential types of future events have no precedent there. This potentially active volcanic center is contained within Crater Lake National Park, visited by 500,000 people per year, and is adjacent to the main transportation corridor east of the Cascade Range. Because a lake is now present within the most likely site of future volcanic activity, many of the hazards at Crater Lake are different from those at most other Cascade volcanoes. Also significant are many faults near Crater Lake that clearly have been active in the recent past. These faults, and historic seismicity, indicate that damaging earthquakes can occur there in the future. This report describes the various types of volcano and earthquake hazards in the Crater Lake area, estimates of the likelihood of future events, recommendations for mitigation, and a map of hazard zones. The main conclusions are summarized below.

  3. Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: hydroclimatic implications

    USGS Publications Warehouse

    Watras, C.J.; Read, J.S.; Holman, K.D.; Liu, Z.; Song, Y.-Y.; Watras, A.J.; Morgan, S.; Stanley, E.H.

    2014-01-01

    We report a unique hydrologic time-series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically-driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13y) is remarkably consistent among small seepage lakes, groundwater tables and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P-E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the mid-latitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by a ~12y downward trend beginning in 1998. Record low water levels region-wide may mark the onset of a new hydroclimatic regime.

  4. Archean and Proterozoic geology of the Lake Superior region, U.S.A., 1993

    USGS Publications Warehouse

    Sims, P.K.; Carter, L.M.H.

    1996-01-01

    This report updates a report on the Precambrian geology of the Lake Superior region published in Geological Society of America's Decade of North American Geology Volume C-2 (1993) on the Precambrianconterminous U.S.

  5. Environmental Indicators for the Coastal Region of North American Great Lakes: Introduction and Prospectus

    EPA Science Inventory

    Environmental indicators are benchmarks for the current conditions of the Great Lakes coastal region and provide measurable endpoints to assess the success of future management, conservation, protection, and restoration of this important resource.

  6. Effects of Land Use on Lake Nutrients: The Importance of Scale, Hydrologic Connectivity, and Region.

    PubMed

    Soranno, Patricia A; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales. PMID:26267813

  7. Effects of land use on lake nutrients: The importance of scale, hydrologic connectivity, and region

    USGS Publications Warehouse

    Soranno, Patricia A.; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E.; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales.

  8. Effects of Land Use on Lake Nutrients: The Importance of Scale, Hydrologic Connectivity, and Region

    PubMed Central

    Soranno, Patricia A.; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E.; Bremigan, Mary Tate

    2015-01-01

    Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales. PMID:26267813

  9. A Fast Algorithm to Estimate the Deepest Points of Lakes for Regional Lake Registration.

    PubMed

    Shen, Zhanfeng; Yu, Xinju; Sheng, Yongwei; Li, Junli; Luo, Jiancheng

    2015-01-01

    When conducting image registration in the U.S. state of Alaska, it is very difficult to locate satisfactory ground control points because ice, snow, and lakes cover much of the ground. However, GCPs can be located by seeking stable points from the extracted lake data. This paper defines a process to estimate the deepest points of lakes as the most stable ground control points for registration. We estimate the deepest point of a lake by computing the center point of the largest inner circle (LIC) of the polygon representing the lake. An LIC-seeking method based on Voronoi diagrams is proposed, and an algorithm based on medial axis simplification (MAS) is introduced. The proposed design also incorporates parallel data computing. A key issue of selecting a policy for partitioning vector data is carefully studied, the selected policy that equalize the algorithm complexity is proved the most optimized policy for vector parallel processing. Using several experimental applications, we conclude that the presented approach accurately estimates the deepest points in Alaskan lakes; furthermore, we gain perfect efficiency using MAS and a policy of algorithm complexity equalization. PMID:26656598

  10. A Fast Algorithm to Estimate the Deepest Points of Lakes for Regional Lake Registration

    PubMed Central

    Shen, Zhanfeng; Yu, Xinju; Sheng, Yongwei; Li, Junli; Luo, Jiancheng

    2015-01-01

    When conducting image registration in the U.S. state of Alaska, it is very difficult to locate satisfactory ground control points because ice, snow, and lakes cover much of the ground. However, GCPs can be located by seeking stable points from the extracted lake data. This paper defines a process to estimate the deepest points of lakes as the most stable ground control points for registration. We estimate the deepest point of a lake by computing the center point of the largest inner circle (LIC) of the polygon representing the lake. An LIC-seeking method based on Voronoi diagrams is proposed, and an algorithm based on medial axis simplification (MAS) is introduced. The proposed design also incorporates parallel data computing. A key issue of selecting a policy for partitioning vector data is carefully studied, the selected policy that equalize the algorithm complexity is proved the most optimized policy for vector parallel processing. Using several experimental applications, we conclude that the presented approach accurately estimates the deepest points in Alaskan lakes; furthermore, we gain perfect efficiency using MAS and a policy of algorithm complexity equalization. PMID:26656598

  11. Nutrient enrichment homogenizes lake benthic assemblages at local and regional scales.

    PubMed

    Donohue, Ian; Jackson, Andrew L; Pusch, Martin T; Irvine, Kenneth

    2009-12-01

    The compositional heterogeneity of biotic assemblages among sites, or beta-diversity, regulates the relationship between local and regional species diversity across scales. Recent work has suggested that increased harshness of environmental conditions tends to reduce beta-diversity by decreasing the importance of stochastic processes in structuring assemblages. We investigated the effect of nutrient enrichment on the compositional heterogeneity of lake benthic invertebrate assemblages in Ireland at both local (within-lake) and regional (among-lake) scales. At local scales, we found that the compositional heterogeneity of benthic assemblages was related inversely to the extent of nutrient enrichment (as indicated by measurements of water column total phosphorus, total nitrogen, and chlorophyll a), after effects of lake morphology (i.e., surface area, connectivity, and depth of sampling) and alkalinity were accounted for. At regional scales, we found that nutrient-rich lakes had significantly more homogenous benthic assemblages than nutrient-poor lakes, over and above the effect of alkalinity and across a similar range of lake morphologies. These findings have profound implications for global aquatic biodiversity, as the homogenization of benthic assemblages at both local and regional scales may have important and unpredictable effects on whole aquatic ecosystems, with potentially considerable ecological and evolutionary consequences. PMID:20120814

  12. Application of Landsat 8 imagery to regional-scale assessment of lake water quality

    NASA Astrophysics Data System (ADS)

    Andrzej Urbanski, Jacek; Wochna, Agnieszka; Bubak, Iwona; Grzybowski, Waldemar; Lukawska-Matuszewska, Katarzyna; Łącka, Magda; Śliwińska, Sylwia; Wojtasiewicz, Bożena; Zajączkowski, Marek

    2016-09-01

    The aim of the project was to create a tool with which to support regional lake quality assessment using Landsat 8 imagery data. The model of assigning the ecological status was implemented in GIS for the northern part of Poland and classifies lake quality for several classes according to classification of WFD using two basic assumptions. The first is that there exists a combination of OLI bands (OLI2/OLI4 was used) which correlates well with the trophic state of the lakes; the second assumption is that the reference trophic state depends on the mean depth of the lake. The model uses a lake geodatabase which contains lakes outlines, raster masks of lakes and attribute information about their mean depth. There is no need to provide any field data when using this tool, as calibration of the model is done using subsets of lakes which were classified using legally defined methods. The tool allows fast classification of 2800 lakes from the area of interest. The results show good agreement between satellite and expert based methods.

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

    PubMed

    Jernström, J; Lehto, J; Dauvalter, V A; Hatakka, A; Leskinen, A; Paatero, J

    2010-02-01

    Sediment cores collected from different locations of Lake Umbozero were studied with respect to concentration and mobility of trace and heavy metals Co, Cu, Fe, Mn, Ni, Pb, U, and Zn. Lake Umbozero is the second largest lake in the Murmansk Region and subjected to contamination by air-borne emissions and river transportation from the nearby metallurgical and mining industries. Unlike its neighboring, more industry-prone Lake Imandra, Lake Umbozero is relatively unexplored with respect to its state of pollution. In our study, metal distribution in sediments was found to vary with respect to the cores, although in general the concentrations were at the same level throughout the lake indicating uniform horizontal distribution of metals. When compared to Lake Imandra, the concentrations of most of the metals studied were significantly lower and represented the levels in sediments measured in lakes of Kola Peninsula located further off from industrial pollutant sources. An exception was Pb the concentration of which was at the same level as in Lake Imandra, probably due to long-distance transport. Sediment layers were subjected to four-step sequential extraction procedure to reveal the metal distribution in soluble, exchangeable, acid-soluble, and residual fractions. Indicative of their potential higher lability, Mn, U, and Zn were generally found in exchangeable fraction; as also Mn and U extensively in the acid-soluble fraction. PMID:19184485

  14. Lake Urmia (Iran): can future socio-ecologically motivated river basin management restore lake water levels in an arid region with extensive agricultural development?

    NASA Astrophysics Data System (ADS)

    Fazel, Nasim; Berndtsson, Ronny; Bertacchi Uvo, Cintia; Klove, Bjorn; Madani, Kaveh

    2015-04-01

    Lake Urmia, one of the world's largest hyper saline lakes located in northwest of Iran, is a UNESCO Biosphere Reserve and Ramsar site, protected as a national park and, supports invaluable and unique biodiversity and related ecosystem services for the region's 6.5 million inhabitants. Due to increased development of the region's water resources for agriculture and industry and to a certain extent climate change, the lake has started to shrink dramatically since 1995 and now is holding less than 30 percent of its volume. Rapid development in agricultural sector and land-use changes has resulted in immense construction of dams and water diversions in almost all lake feeding rivers, intensifying lake shrinking, increasing salinity and degrading its ecosystem. Recently, lake's cultural and environmental importance and social pressure has raised concerns and brought government attention to the lake restoration plans. Along with poor management, low yield agriculture as the most water consuming activity in the region with, rapid, insufficient development is one of the most influential drivers in the lake desiccation. Part of the lake restoration plans in agricultural sector is to restrict the agricultural areas in the main feeding river basins flowing mostly in the southern part of the lake and decreasing the agricultural water use in this area. This study assess the efficiency and effectiveness of the proposed plans and its influence on the lake level rise and its impacts on economy in the region using a system dynamics model developed for the Lake consist of hydrological and agro-economical sub-systems. The effect of decrease in agricultural area in the region on GDP and region economy was evaluated and compared with released water contribution in lake level rise for a five year simulation period.

  15. Empirical relationships between watershed attributes and headwater lake chemistry in the Adirondack region

    SciTech Connect

    Hunsaker, C.T.; Christensen, S.W.; Beauchamp, J.J.; Olson, R.J.; Turner, R.S.; Malanchuk, J.L.

    1986-12-01

    This study focuses on the Adirondack region of New York and has two purposes: to (1) develop empirical models that can be used to assess the chemical status of lakes for which no chemistry data exist and (2) determine on a regional scale watershed attributes that account for variability in lake pH and acid-neutralizing capacity (ANC). Headwater lakes, rather than lakes linked to upstream lakes, were selected for initial analysis. Both bivariate (correlations and Wilcoxon and Kruskal-Wallis tests) and multivariate analyses were performed. Fifty-seven watershed attributes were selected as input variables to multiple linear regression and discriminant analysis. For model development approx.200 lakes for which pH and ANC data exist were randomly subdivided into a specification and a verification data set. Several indices were used to select models for predicting lake pH (31 variables) and ANC (27 variables). Twenty-five variables are common to the pH and ANC models: four lake morphology, nine soil/geology, eight land cover, three disturbance, and one watershed aspect. An atmospheric input variable (H/sup +/ or NO/sub 3//sup -/) explains the greatest amount of variation in the dependent variable (pH and ANC) for both models. The percentage of watershed in conifers is the next strongest predictor variable. For all headwater lakes in the Adirondacks, approx.60% of the lakes are estimated to have an ANC less than or equal to50 ..mu..eq/L, and 40% of the lakes have a pH less than or equal to5.5, levels believed to be detrimental to some fish species.

  16. Regional Analysis of the Hazard Level of Glacial Lakes in the Cordillera Blanca, Peru

    NASA Astrophysics Data System (ADS)

    Chisolm, Rachel E.; Jhon Sanchez Leon, Walter; McKinney, Daene C.; Cochachin Rapre, Alejo

    2016-04-01

    The Cordillera Blanca mountain range is the highest in Peru and contains many of the world's tropical glaciers. This region is severely impacted by climate change causing accelerated glacier retreat. Secondary impacts of climate change on glacier retreat include stress on water resources and the risk of glacial lake outburst floods (GLOFs) from the many lakes that are forming and growing at the base of glaciers. A number of GLOFs originating from lakes in the Cordillera Blanca have occurred over the last century, several of which have had catastrophic impacts on cities and communities downstream. Glaciologists and engineers in Peru have been studying the lakes of the Cordillera Blanca for many years and have identified several lakes that are considered dangerous. However, a systematic analysis of all the lakes in the Cordillera Blanca has never before been attempted. Some methodologies for this type of systematic analysis have been proposed (eg. Emmer and Vilimek 2014; Wang, et al. 2011), but as yet they have only been applied to a few select lakes in the Cordillera Blanca. This study uses remotely sensed data to study all of the lakes of the Glacial Lake Inventory published by the Glaciology and Water Resources Unit of Peru's National Water Authority (UGRH 2011). The objective of this study is to assign a level of potential hazard to each glacial lake in the Cordillera Blanca and to ascertain if any of the lakes beyond those that have already been studied might pose a danger to nearby populations. A number of parameters of analysis, both quantitative and qualitative, have been selected to assess the hazard level of each glacial lake in the Cordillera Blanca using digital elevation models, satellite imagery, and glacier outlines. These parameters are then combined to come up with a preliminary assessment of the hazard level of each lake; the equation weighting each parameter draws on previously published methodologies but is tailored to the regional characteristics

  17. Water Quality and Evaluation of Pesticides in Lakes in the Ridge Citrus Region of Central Florida

    USGS Publications Warehouse

    Choquette, Anne F.; Kroening, Sharon E.

    2009-01-01

    Water chemistry, including major inorganic constituents, nutrients, and pesticide compounds, was compared between seven lakes surrounded by citrus agriculture and an undeveloped lake on the Lake Wales Ridge (herein referred to as the Ridge) in central Florida. The region has been recognized for its vulnerability to the leaching of agricultural chemicals into the subsurface due to factors including soils, climate, and land use. About 40 percent of Florida's citrus cultivation occurs in 'ridge citrus' areas characterized by sandy well drained soils, with the remainder in 'flatwoods citrus' characterized by high water tables and poorly drained soils. The lakes on the Ridge are typically flow-through lakes that exchange water with adjacent and underlying aquifer systems. This study is the first to evaluate the occurrence of pesticides in lakes on the Ridge, and also represents one of the first monitoring efforts nationally to focus on regional-scale assessment of current-use pesticides in small- to moderate-sized lakes (5 to 393 acres). The samples were collected between December 2003 and September 2005. The lakes in citrus areas contained elevated concentrations of major inorganic constituents (including alkalinity, total dissolved solids, calcium, magnesium, sodium, potassium, chloride, and sulfate), total nitrogen, pH, and pesticides compared to the undeveloped lake. Nitrate (as N) and total nitrogen concentrations were typically elevated in the citrus lakes, with maximum values of 4.70 and 5.19 mg/L (milligrams per liter), respectively. Elevated concentrations of potassium, nitrate, and other inorganic constituents in the citrus lakes likely reflect inputs from the surficial ground-water system that originated predominantly from agricultural fertilizers, soil amendments, and inorganic pesticides. A total of 20 pesticide compounds were detected in the lakes, of which 12 compounds exceeded the standardized reporting level of 0.06 ug/L (microgram per liter). Those

  18. The impacts of thawing permafrost on tundra lakes, Mackenzie Delta region, NWT, Canada. (Invited)

    NASA Astrophysics Data System (ADS)

    Kokelj, S.; Thompson, M. S.; Lantz, T.; Thienpont, J.; Pisaric, M. F.; Smol, J. P.; Blais, J.; Zajdlik, B.

    2009-12-01

    Many arctic regions with abundant lakes and ponds are characterized by ice-rich terrain sensitive to thermokarst disturbance. In the Mackenzie Delta region, retrogressive thaw slumps commonly develop adjacent to tundra lakes and may impact several hectares of terrain. The numbers, size and growth rates of slumps have increased significantly since the 1970s with rising air and permafrost temperatures. To examine the chemical effects of thawing permafrost on lake water quality we assessed water chemistry for large number of slump-disturbed and undisturbed lakes across tundra uplands in the Mackenzie Delta region. The environmental factors typically evoked to explain variation in tundra lake water quality, including surficial geology and proximity to the treeline or to the coast, were subordinate to the main driver, permafrost degradation. Thaw slump-affected lakes had elevated ionic concentrations and water clarity in comparison with undisturbed lakes. The strength of the ionic impact was positively associated with the proportion of catchment affected by slumping and inversely related to disturbance age. We also found that fire-induced active-layer deepening had a detectable influence on lake water ionic strength. Preliminary evidence suggests sedimentary diatom assemblages track the changes in chemical and physical limnology coincident with the timing of thermokarst slumping, and thus, may prove a valuable tool for inferring changes at the base of the aquatic food web in these lakes. In a warming arctic, we can anticipate that thermokarst processes will increase in importance as a driver of ionic chemistry and optical properties of small lakes and ponds with potential to alter aquatic food webs.

  19. Source Attribution for Mercury Deposition to the Great Lakes Region in the Context of Global Change

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Fisher, J. A.; Wu, S.; Kumar, A.

    2015-12-01

    Mercury contamination in the Great Lakes region has important implications for human and wildlife health therein. Atmospheric deposition serves as an important pathway for mercury entering into the lakes and mercury originating from sources outside North America also contributes to part of the total mercury deposited to the Great Lakes. Understanding the source apportionment of mercury deposition to the Great Lakes region is critical for policy making. We investigate the present day source attribution of mercury deposition to the Great Lakes region as well as the perturbations driven by various factors in the context of global change (such as the changes in biomass burning emissions, anthropogenic emissions and land use/land cover) using the GEOS-Chem global model. We will quantify the relative contribution of different emission sources (e.g., anthropogenic vs natural) and different regions (e.g., domestic vs intercontinental-transport) to mercury deposition in the Great Lakes region. In addition, we will conduct sensitivity tests to evaluate the model's sensitivity to processes such as atmospheric redox reactions and how it affects the source attribution.

  20. Glacial lake distribution in the Mount Everest region: Uncertainty of measurement and conditions of formation

    NASA Astrophysics Data System (ADS)

    Salerno, Franco; Thakuri, Sudeep; D'Agata, Carlo; Smiraglia, Claudio; Manfredi, Emanuela Chiara; Viviano, Gaetano; Tartari, Gianni

    2012-07-01

    This study provides a complete mapping (October 2008) of glacial lakes and debris-covered glaciers in the Mount Everest region. These types of analyses are essential in studies of the impact of recent climate change, and therefore the uncertainty of measurements is discussed with the aim of creating a reference study for use when glaciers and lakes are delineated using remote sensing imagery. Moreover, attention is focused on conditions related to the formation of lakes, which is the greatest evidence of the impact of climate change at high altitudes characterized by debris-covered glaciers. Regarding the formation process of supraglacial lakes, our findings confirm that the slope of the glacier where lakes are located is primarily responsible for the low flow velocity of this zone. Otherwise, this study is novel in its identification of a further boundary condition. The slope of the glacier upstream is able to influence both the low flow velocity and the high ablation rates at the glacier terminus. In fact, the imbalance between the two glacier zones generates the down-slope passage of debris, snow and ice. We found the slope of the glacier upstream to be inversely correlated with the relevant total surface of the lakes downstream. The multiple regression model developed in this study, considering the slopes of the two glacier areas distinctly, has been able to predict 90% of the supraglacial lake surfaces. Concerning the surfaces of lakes not directly connected with glaciers (unconnected glacial lakes), we found they are correlated with the dimensions of their drainage basin, whereas no correlation was found with the glacier cover in the basin. Considering that the evaporation/precipitation ratio at these altitudes is approximately 0.34, the evolution of these lakes appears to be a helpful sign for detecting the precipitation trend of these high-altitude regions.

  1. A REGIONAL ECOLOGICAL ANALYSIS OF THE GREAT LAKES BASIN

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) and Natural Resources Canada: Canada Centre for Remote Sensing (CCRS) are conducting a cooperative research landscape ecological study of the Great Lakes Basin. The analyses will include the areas located along the border of the Unit...

  2. AIRBORNE MERCURY IN PRECIPITATION IN THE LAKE SUPERIOR REGION

    EPA Science Inventory

    Mercury was measured in accumulated snow (March 1982) sampled from around Lake Superior and in rainfall from Duluth, Minnesota (June-September 1982 and March-November 1983), Forbes Township, and Dorset in northwestern and central Ontario, respectively (May-September 1983). Method...

  3. [Spatial Distribution of Stable Isotope from the Lakes in Typical Temperate Glacier Region].

    PubMed

    Shi, Xiao-yi; Pu, Tao; He, Yuan-qing; Lu, Hao; Niu, He-wen; Xia, Dun-sheng

    2016-05-15

    We focused mainly on the spatial variation and influencing factors of hydrogen and oxygen stable isotopes between water samples collected at the surface and different depths in the Lashi Lake in August, 2014. Hydrological supply characteristics of the lake in typical temperate glacier region were discussed. The results showed that the values of δ¹⁸O and δD in the Lashi Lake ranged from -12.98 per thousand to -8.16 per thousand with the mean of -9.75 per thousand and from -99.42 per thousand to -73.78 per thousand with the mean of -82.23 per thousand, respectively. There was a reversed spatial variation between δ¹⁸O and d. Relatively low values of δ¹⁸O with high values of d were found at the edge of the lake where the rivers drained into. Meanwhile, the values of d in the vertical profile varied little with depth, suggesting that the waters mixed sufficiently in the vertical direction. The d values increased at first and then decreased from east to west at different layers, but both increase and decrease exhibited different velocities, which were related to the river distribution, the locality of the lake and environmental conditions etc. River water and atmospheric precipitation were the main recharge sources of the Lashi Lake, and the melt-water of snow and ice might also be the supply resource. The δ¹⁸O values of lake water in glacier region decreased along the elevation (except for Lashi Lake), generally, this phenomenon was called "altitude effect". Moreover, high isotopic values of the lake water from non-glacier region were due to the evaporation effect. PMID:27506020

  4. Climatic forcing of carbon-oxygen isotopic covariance in temperate-region marl lakes

    NASA Technical Reports Server (NTRS)

    Drummond, C. N.; Patterson, W. P.; Walker, J. C.

    1995-01-01

    Carbon and oxygen stable isotopic compositions of lacustrine carbonate from a southeastern Michigan marl lake display linear covariance over a range of 4.0% Peedee belemnite (PDB) in oxygen and 3.9% (PDB) in carbon. Mechanisms of delta 13 C-delta 18 O coupling conventionally attributed to lake closure in arid-region basins are inapplicable to hydrologically open lake systems. Thus, an alternative explanation of isotopic covariance in temperate region dimictic marl lakes is required. We propose that isotopic covariance is a direct record of change in regional climate. In short-residence-time temperate-region lake basins, summer meteoric precipitation is enriched in 18O relative to winter values, and summer organic productivity enriches epilimnic dissolved inorganic carbon in 13C. Thus, climate change toward longer summers and/or shorter winters could result in greater proportions of warm-month meteoric precipitation, longer durations of warm-month productivity, and net long-term enrichment in carbonate 18O and 13C. Isotopic covariance observed in the Michigan marl lake cores is interpreted to reflect postglacial warming from 10 to 3 ka followed by cooler mean annual temperature, a shift toward greater proportions of seasonal summer precipitation, a shortening of the winter season, or some combination of these three factors.

  5. 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…

  6. Regional economic impacts of water management alternatives: the case of Devils Lake, North Dakota, USA.

    PubMed

    Leistritz, F Larry; Leitch, Jay A; Bangsund, Dean A

    2002-12-01

    Devils Lake, located in a closed basin in northeastern North Dakota has over a century-long history of highly fluctuating water levels. The lake has risen nearly 25 feet (7.7 m) since 1993, more than doubling its surface area. Rising water levels have affected rural lands, transportation routes, and communities near the lake. In response to rising lake levels, Federal, state and local agencies have adopted a three-part approach to flood damage reduction, consisting of (1) upper basin water management to reduce the amount of water reaching the lake, (2) protection for structures and infrastructure if the lake continues to rise, and (3) developing an emergency outlet to release some lake water. The purpose of this study was to provide information about the net regional economic effects of a proposed emergency outlet for Devils Lake. An input-output model was used to estimate the regional economic effects of the outlet, under two scenarios: (1) the most likely future situation (MLS) and (2) a best case situation (BCS) (i.e., where the benefits from the outlet would be greatest), albeit an unlikely one. Regional economic effects of the outlet include effects on transportation (road and railroad construction), agriculture (land kept in production, returned to production sooner, or kept in production longer), residential relocations, and outlet construction expenditures. Effects are measured as changes in gross business volume (gross receipts) for various sectors, secondary employment, and local tax collections. The net regional economic effects of the proposed outlet would be relatively small, and consideration of these economic impacts would not strengthen the case for an outlet. PMID:12503500

  7. Isotopic Evolution of Saline Lakes in the Low-Latitude and Polar Regions

    SciTech Connect

    Horita, Juske

    2009-01-01

    Isotopic fractionations associated with two primary processes (evaporation and freezing of water) are discussed, which are responsible for the formation and evolution of saline lakes in deserts from both low-latitude and the Polar regions. In an evaporative system, atmospheric parameters (humidity and isotopic composition of water vapor) have strong influence on the isotopic behavior of saline lakes, and in a freezing system, salinity build-up largely controls the extent of freezing and associated isotope fractionation. In both systems, salinity has a direct impact on the isotopic evolution of saline lakes. It is proposed that a steady-state 'terminal lake' model with short-term hydrologic and environmental perturbations can serve as a useful framework for investigating both evaporative and freezing processes of perennial saline lakes. Through re-assessment of own work and literature data for saline lakes, it was demonstrated that effective uses of the isotope activity compositions of brines and salinity-chemistry data could reveal dynamic changes and evolution in the isotopic compositions of saline lakes in response to hydrologic and environmental changes. The residence time of isotopic water molecules in lakes determines the nature of responses in the isotopic compositions following perturbations in the water and isotope balances (e.g., dilution by inflow, water deficit by increased evaporation, and/or reduction in inflow). The isotopic profiles of some saline lakes from the Polar regions show that they switched the two contrasting modes of operation between evaporative and freezing systems, in response to climate and hydrological changes in the past.

  8. Isotopic evolution of saline lakes in the low-latitude and polar regions

    SciTech Connect

    Horita, Juske

    2009-01-01

    Isotopic fractionations associated with two primary processes (evaporation and freezing of water) are discussed, which are responsible for the formation and evolution of saline lakes in deserts from both low-latitude and the Polar regions. In an evaporative system, atmospheric parameters (humidity and isotopic composition of water vapor) have strong influence on the isotopic behavior of saline lakes, and in a freezing system, salinity build-up largely controls the extent of freezing and associated isotope fractionation. In both systems, salinity has a direct impact on the isotopic evolution of saline lakes. It is proposed that a steady-state terminal lake model with short-term hydrologic and environmental perturbations can serve as a useful framework for investigating both evaporative and freezing processes of perennial saline lakes. Through re-assessment of own work and literature data for saline lakes, it was demonstrated that effective uses of the isotope activity compositions of brines and salinity-chemistry data could reveal dynamic changes and evolution in the isotopic compositions of saline lakes in response to hydrologic and environmental changes. The residence time of isotopic water molecules in lakes determines the nature of responses in the isotopic compositions following perturbations in the water and isotope balances (e.g., dilution by inflow, water deficit by increased evaporation, and/ or reduction in inflow). The isotopic profiles of some saline lakes from the Polar regions show that they switched the two contrasting modes of operation between evaporative and freezing systems, in response to climate and hydrological changes in the past.

  9. Reconciling geography and genealogy: phylogeography of giant freshwater prawns from the Lake Carpentaria region.

    PubMed

    de Bruyn, Mark; Wilson, John C; Mather, Peter B

    2004-11-01

    There is convincing geological evidence for the historical existence of an ancient lake on the Australian-New Guinea continental shelf during the late Pleistocene. Lake Carpentaria was a vast fresh- to brackishwater lake that would presumably have provided habitat for, and facilitated gene flow among, aquatic taxa that tolerate low to moderate salinities in this region. Moreover, it has been argued that the outflow of Papua New Guinea's Fly River was diverted westward into Lake Carpentaria during this period, although this hypothesis is controversial. We predicted that these events, if a true history, would have promoted gene flow and population growth via range-expansion events in the giant freshwater prawn (Macrobrachium rosenbergii) and restricted gene flow subsequently by way of a vicariant event as sea levels rose during the late Pleistocene, and a marine environment replaced Lake Carpentaria. We tested these hypotheses using phylogeographical and phylogenetic analyses of mitochondrial DNA variation in M. rosenbergii populations sampled from the Lake Carpentaria region. Our results support the hypothesis that Lake Carpentaria facilitated gene flow among populations of M. rosenbergii that are today isolated, but contest claims of a westward diversion of the Fly River. We inferred the timing of initial expansion in the 'Lake Carpentaria lineage' and found the timing of this event to be broadly concordant with geological dating of the formation of Lake Carpentaria. Reconciling geological and molecular data, as presented here, provides a powerful framework for investigating the influence of historical earth history events on the distribution of biological (i.e. molecular) diversity. PMID:15488008

  10. Empirical Relationships Between Watershed Attributes and Headwater Lake Chemistry in the Adirondack Region

    SciTech Connect

    Hunsaker, C.T.

    1987-01-01

    Surface water acidification may be caused or influenced by both natural watershed processes and anthropogenic actions. Empirical models and observational data can be useful for identifying watershed attributes or processes that require further research or that should be considered in the development of process models. This study focuses on the Adirondack region of New York and has two purposes: to (1) develop empirical models that can be used to assess the chemical status of lakes for which no chemistry data exist and (2) determine on a regional scale watershed attributes that account for variability in lake pH and acid-neutralizing capacity (ANC). Headwater lakes, rather than lakes linked to upstream lakes, were selected for initial analysis. The Adirondacks Watershed Data Base (AWDB), part of the Acid Deposition Data Network maintained at Oak Ridge National Laboratory (ORNL), integrates data on physiography, bedrock, soils, land cover, wetlands, disturbances, beaver activity, land use, and atmospheric deposition with the water chemistry and morphology for the watersheds of 463 headwater lakes. The AWD8 facilitates both geographic display and statistical analysis of the data. The report, An Adirondack Watershed Data Base: Attribute and Mapping Information for Regional Acidic Deposition Studies (ORNL/TM--10144), describes the AWDB. Both bivariate (correlations and Wilcoxon and Kruskal-Wallis tests) and multivariate analyses were performed. Fifty-seven watershed attributes were selected as input variables to multiple linear regression and discriminant analysis. For model development -200 lakes for which pH and ANC data exist were randomly subdivided into a specification and a verification data set. Several indices were used to select models for predicting lake pH (31 variables) and ANC (27 variables). Twenty-five variables are common to the pH and ANC models: four lake morphology, nine soil/geology, eight land cover, three disturbance, and one watershed aspect. An

  11. ENVIRONMENTAL AUDITING: Regional Lake Trophic Patterns in the Northeastern United States: Three Approaches

    PubMed

    1998-09-01

    / During the summers of 1991-1994, the Environmental Monitoring and Assessment Program (EMAP) conducted variable probability sampling on 344 lakes throughout the northeastern United States. Trophic state data were analyzed for the Northeast as a whole and for each of its three major ecoregions-the Adirondacks (ADI), the New England Uplands (NEU), and the Coastal Lowland and Plateau (CLP)-and inferred to the entire population of lakes >/=1 ha (N = 11,076). Results were compared to a large, nonrandomly sampled data set for the same area compiled by Rohm and others and contrasted with lake trophic state information published in the National Water Quality Inventory: 1994 Report to Congress [305(b) report. Lakes across the entire Northeast were identified by EMAP data as 37.9% (+/-8.4%) oligotrophic, 40.1% (+/-9.7%) mesotrophic, 12.6% (+/-7.9%) eutrophic, and 9.3% (+/-6.3%) hypereutrophic. Lakes in the ADI and NEU generally are at a low, nearly identical trophic state (96% oligotrophic/mesotrophic), while those in the CLP are much richer (45% eutrophic). EMAP results are similar to results of the Rohm data set across the entire region. In the CLP, however, EMAP identified approximately 45% of the lakes as eutrophic/hypereutrophic, while the Rohm data set identified only 21% in these categories. Across the entire Northeast, the 305(b) report identified a much higher proportion (32.2%) of lakes in eutrophic condition and a much smaller proportion (19.8%) in oligotrophic condition than did the EMAP survey data (12.5% +/- 7.9% and 37.9% +/- 8.5%, respectively). Probability sampling has several advantages over nonrandom sampling when regional resource condition assessment is the goal.KEY WORDS: Lake trophic state; Phosphorus; Probability survey; Regional condition PMID:9680546

  12. A Study of Library Service in the Lake Agassiz Region of North Dakota.

    ERIC Educational Resources Information Center

    North Dakota State Library Commission, Bismarck.

    A needs assessment of the library services of the Lake Agassiz region of North Dakota was begun in 1974. A mail survey of the area population and an in-library user survey were conducted. Almost all libraries in the region fell below state standards on holdings primarily because the population base was inadequate to support 11 municipal libraries.…

  13. Learning about War and Peace in the Great Lakes Region of Africa

    ERIC Educational Resources Information Center

    Bird, Lyndsay

    2007-01-01

    Two-thirds of the world's conflicts are in Africa. In particular, the Great Lakes region (Rwanda, Burundi, Democratic Republic of Congo, Uganda and Tanzania) continues to see conflicts that are complex, extreme and seemingly intractable. By exploring the narrative experiences of those most affected by the conflicts in the region--specifically…

  14. Identification of nitrogen sources to four small lakes in the agricultural region of Khorezm, Uzbekistan

    USGS Publications Warehouse

    Shanafield, M.; Rosen, M.; Saito, L.; Chandra, S.; Lamers, J.; Nishonov, Bakhriddin

    2010-01-01

    Pollution of inland waters by agricultural land use is a concern in many areas of the world, and especially in arid regions, where water resources are inherently scarce. This study used physical and chemical water quality and stable nitrogen isotope (δ15N) measurements from zooplankton to examine nitrogen (N) sources and concentrations in four small lakes of Khorezm, Uzbekistan, an arid, highly agricultural region, which is part of the environmentally-impacted Aral Sea Basin. During the 2-year study period, ammonium concentrations were the highest dissolved inorganic N species in all lakes, with a maximum of 3.00 mg N l−1 and an average concentration of 0.62 mg N l−1. Nitrate levels were low, with a maximum concentration of 0.46 mg N l−1 and an average of 0.05 mg N l−1 for all four lakes. The limited zooplankton δ15N values did not correlate with the high loads of synthetic fertilizer applied to local croplands during summer months. These results suggest that the N cycles in these lakes may be more influenced by regional dynamics than agricultural activity in the immediate surroundings. The Amu-Darya River, which provides the main source of irrigation water to the region, was identified as a possible source of the primary N input to the lakes.

  15. A comparison of lakes in the Kolyma River region that receive inputs of Holocene and Pleistocene origin

    NASA Astrophysics Data System (ADS)

    Henriksen, E. H.; Vonk, J. E.; Schade, J. D.; Mann, P. J.; Bulygina, E. B.; Sobczak, W. V.; Zimov, S. A.; Holmes, R. M.

    2011-12-01

    The Siberian Arctic contains vast amounts of carbon stored in permafrost soils. Throughout this region there are many lakes and rivers that receive input of organic matter from terrestrial sources. Previous research suggests that these freshwater ecosystems are actively processing carbon, rather than functioning only as passive transporters. Ongoing climate warming in this vulnerable region is expected to cause increasing permafrost thaw and a likely increase of the inflow of permafrost-derived carbon to freshwater ecosystems. We aim to improve our understanding of how these freshwater ecosystems are processing carbon to increase our ability to predict how climate change will affect this region. This study was performed in July 2011 as part of the Polaris Project (www.polarisproject.org). We focused upon lakes in the Kolyma River watershed, the world's largest river underlain by continuous permafrost. These lakes receive inputs of allochthonous material from either Holocene (floodplain lakes) or Pleistocene (yedoma lakes) soils. We sampled a range of lakes (floodplain n=3; yedoma n=3) for DOC concentration and lability, by means of biological oxygen demand assays, in combination with N and P measurements and water column profiles (oxygen concentrations, pH, specific conductivity and temperature). Chlorophyll a concentrations were measured as a comparison of autochthonous production between lakes. Our findings indicate that yedoma lakes are generally stratified but also display a high variability in their vertical structure over relatively short time scales (the fieldwork took place over three weeks). Furthermore, floodplain lakes had more than twice the concentration of chlorophyll a in the surface water as yedoma lakes, suggesting more autotrophic production. Yedoma lakes contained approximately 40% more DOC than floodplain lakes in surface waters. However, the lability of yedoma lake DOC was half that of floodplain lakes. The higher concentrations of DOC within

  16. Use of wetlands under USEPA's (Environmental Protection Agency's) Region 5 Clean Lakes Program. Master's thesis

    SciTech Connect

    Landers, J.C.

    1989-05-01

    The EPA's Region V Clean Lakes Program uses several wetlands for controlling degradation of publicly owned, freshwater lakes. The study seeks to determine if the objectives of the Clean Lakes Program are being met by this use of wetlands, and if appropriate institutional arrangements and management techniques are being implemented to manage the wetlands. Conclusions regarding Revion V's use and management of wetlands include: wetland projects are not being monitored adequately for effectiveness and potential negative impacts on ecosystems; other mechanisms which may help to protect wetlands are being employed; management of most wetland projects is decentralized appropriately; most of the wetland projects provide for adequate short-term mass balance studies, prior sedimentation, plant species diversity, water level, retention time, uniform flow of water, and upland pollutant management; and existing evidence suggests that the Clean Lakes wetland projects are instrumental in meeting Program goals and objectives. Based on these conclusions several recommendations for improving wetlands management are reviewed.

  17. Impact of lake-river connectivity and interflow on the Canadian RCM simulated regional climate and hydrology for Northeast Canada

    NASA Astrophysics Data System (ADS)

    Huziy, O.; Sushama, L.

    2016-04-01

    Lakes affect regional climate by modulating surface albedo, surface energy, and moisture budgets. This is especially important for regions such as Northeast Canada with approximately 10 % of the landmass covered by lakes, wetlands and rivers. From the regional hydrology perspective, interactions between lakes and rivers are important as streamflow patterns can be significantly modified by lake storage, and similarly lake levels can be modified by streamflows. In this study, using a suite of experiments performed with the fifth generation Canadian Regional Climate Model (CRCM5) driven by the European Centre for Medium range Weather Forecasting ERA40 reanalysis data at the lateral boundaries for the 1979-2010 period, lake-river-atmosphere interactions and their impact on the regional climate/hydrology of north-east Canada are assessed. In these CRCM5 simulations, a one-dimensional lake model represents lakes, while the rivers are modeled using a distributed routing scheme, and one of the simulations includes interflow, i.e. lateral flow of water in the soil layers. Comparison of CRCM5 simulations with and without lakes suggests significant differences in winter/summer precipitation and winter temperature for the study region. CRCM5 simulations performed with and without lake-river interactions suggest improved representation of streamflows when lake storage and routing are taken into account. Adding the interflow process leads to increased streamflows during summer and fall seasons for the majority of the rivers, causing modest changes to land-atmosphere interactions via modified soil moisture. The impact of interflow on streamflow, obtained in this study, is comparable to the impact of lake-atmosphere interactions on streamflows. This study clearly demonstrates the need for realistic representation of lake-river interactions in regional climate models for realistic simulation of regional hydrology, particularly streamflows.

  18. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS).

    PubMed

    Nyamweya, Chrispine; Desjardins, Christopher; Sigurdsson, Sven; Tomasson, Tumi; Taabu-Munyaho, Anthony; Sitoki, Lewis; Stefansson, Gunnar

    2016-01-01

    Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS) to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May) and mixing (June-August). Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza) and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents) that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria. PMID:27030983

  19. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS)

    PubMed Central

    Sigurdsson, Sven; Tomasson, Tumi; Taabu-Munyaho, Anthony; Sitoki, Lewis; Stefansson, Gunnar

    2016-01-01

    Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS) to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September–May) and mixing (June–August). Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza) and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents) that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore—offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria. PMID:27030983

  20. Using a Coupled Lake Model with WRF to Improve High-Resolution Regional Climate Simulations

    NASA Astrophysics Data System (ADS)

    Mallard, M.; Bullock, R.; Nolte, C. G.; Alapaty, K.; Otte, T.; Gula, J.

    2012-12-01

    Lakes can play a significant role in regional climate by modifying air masses through fluxes of heat and moisture and by modulating inland extremes in temperature. Representing these effects becomes more important as regional climate modeling efforts employ finer grid spacing in order to simulate smaller scales. The Weather Research and Forecasting (WRF) model does not simulate lakes explicitly. Instead, lake points are treated as ocean points, with sea surface temperatures (SSTs) interpolated from the nearest neighboring ocean point in the driving coarse-scale fields. This can result in substantial errors for inland lakes such as the Great Lakes. Although prescribed lake surface temperatures (LSTs) can be used for retrospective modeling applications, this may not be desirable for applications involving downscaling future climate scenarios from a global climate model (GCM). In such downscaling simulations, lakes that impact the regional climate in the area of interest may not be resolved by the coarser global input fields. Explicitly simulating the LST would allow WRF to better represent interannual variability in regions significantly affected by lakes, and the influence of such variability on temperature and precipitation patterns. Therefore, coupling a lake model to WRF may lead to more reliable assessments of the impacts of extreme events on human health and the environment. We employ a version of WRF coupled to the Freshwater Lake model, FLake (Gula and Peltier 2012). FLake is a 1D bulk lake model which provides updated LSTs and ice coverage throughout the integration. This two-layer model uses a temperature-depth profile which includes a homogeneous mixed layer at the surface and a thermocline below. The shape of the thermocline is assumed, based on past theoretical and observational studies. Therefore, additional variables required for FLake to run are minimal, and it does not require tuning for individual lakes. These characteristics are advantageous for a

  1. Lake phosphorus loading from septic systems by seasonally perched ground water, Puget Sound region, Washington

    USGS Publications Warehouse

    Gilliom, Robert J.; Patmont, Clayton R.

    1982-01-01

    In a previous study, estimated phosphorus (P) loadings from septic systems to lakes in the Puget Sound region were found to be correlated with the presence of old homes around the lakes. In the present study, we assessed the movement of septic-effluent P in seasonally perched ground water near Pine Lake, a typical glacial-till lake in the region. This ground water occurs in soils overlying less permeable glacial till, which is prevalent around Pine Lake and many other lakes in the area. Water samples were taken from 15 shallow (<1.5 meters) wells installed 10-50 meters downgradient from seven septic systems 20 to 40 years old. The equivalent volumetric fraction of each sample consisting of undiluted effluent was estimated from chloride concentration. Using Monte Carlo analysis to account for the various sources of uncertainty, we found that, though movement of diluted septic effluent to the lake was common, transport of more than 1% of effluent P through the soil was probable (p > or = 0.5) for only 4 of 26 samples, was transport of more than 10% of effluent P probable. The highest probabilities of P movement were associated with two samples from a well that was downgradient from a drainfield located at the base of a hillslope depression where perched ground water concentrates and remains for extended periods. All evidence considered, most P loading to Pine Lake from septic systems appears to come from only a few older systems located in areas where perched ground-water flow and associated saturated soil conditions predominate for extended periods during the winter season. (USGS)

  2. Petrologic considerations for hot dry rock geothermal site selection in the Clear Lake Region, California

    SciTech Connect

    Stimac, J.; Goff, F. ); Hearn, B.C. Jr. )

    1992-01-01

    The Clear Lake area is well known for anomalous heat flow, thermal springs, hydrothermal mineral deposits, and Quaternary volcanism. These factors, along with the apparent lack of a large reservoir of geothermal fluid north of Collayomi fault make the Clear Lake area an attractive target for hot dry rock (HDR) geothermal development. Petrologic considerations provide some constraints on site selection for HDR development. Spatial and temporal trends in volcanism in the Coast Ranges indicate that magmatism has migrated to the north with time, paralleling passage of the Mendocino triple junction and propagation of the San Andreas fault. Volcanism in the region may have resulted from upwelling of hot asthenosphere along the southern margin of the subducted segment of the Gorda plate. Spatial and temporal trends of volcanism within the Clear Lake volcanic field are similar to larger-scale trends of Neogene volcanism in the Cost Ranges. Volcanism (especially for silicic compositions) shows a general migration to the north over the {approximately}2 Ma history of the field, with the youngest two silicic centers located at Mt. Konocti and Borax Lake. The Mt. Konocti system (active from {approximately} 0.6 to 0.3 Ma) was large and long-lived, whereas the Borax Lake system is much smaller but younger (0.09 Ma). Remnants of silicic magma bodies under Mt. Konocti may be in the latter stages of cooling, whereas a magma body centered under Borax Lake may be in the early stages of development. The existence of an upper crustal silicic magma body of under Borax Lake has yet to be demonstrated by passive geophysics, however, subsurface temperatures in the area as high (> 200{degrees}C at 2000 m) as those beneath the Mt. Konocti area. Based on petrologic considerations alone, the Mt. Konocti-Borax Lake area appears to be the most logical choice for HDR geothermal development in the region.

  3. Predator-prey relations and competition for food between age-0 lake trout and slimy sculpins in the Apostle Island region of Lake Superior

    USGS Publications Warehouse

    Hudson, Patrick L.; Savino, Jacqueline F.; Bronte, Charles R.

    1995-01-01

    Slimy sculpins (Cottus cognatus) are an important component of the fish community on reefs and adjacent nursery areas of the Great Lakes and overlap spatially with age-0 lake trout (Salvelinus namaycush). Important interactions between these fishes are possible during the lake trout's first year of life, which could include predation on each other's eggs and larvae, and competition for food resources. We investigated the diets of age-0 lake trout and slimy sculpins on a lake trout spawning reef (Gull Island Shoal) and adjacent nursery area (near Michigan Island) in the Apostle Island region of western Lake Superior during June through September from 1988 through 1991. Organisms in stomachs of 511 lake trout and 562 sculpins were identified and counted. Of the 11 major food types found in age-0 lake trout stomachs from both areas, Mysis was the dominant food item (mean volume in stomachs = 68%) and occurred in about 3/4 of the fish analyzed. Copepods, cladocerans, chironomid pupae, fish, and Bythotrephes were also common in the diet (frequency of occurrence > 4%). Diets of lake trout were more diverse on the reef than on the nursery area where Mysis dominated the diet. Slimy sculpins were only found in lake trout greater than 50 mm. Mysis was an important food item of slimy sculpins over the reef but not over the nursery area, where Diporeia was by far the most important taxon. A variety ofben-thic invertebrates (Asellus, chironomids, benthic copepods, and snails) comprised the bulk of the sculpin diet over the reef. Sculpins also ate lake trout eggs in November. Based on cluster analysis, diets were most similar over the reef where both consumed Mysis, calanoid copepods and chironomid pupae. Diets diverged over the nursery areas where sculpins were strictly benthic feeders and lake trout maintained their planktonic diet. In Lake Superior, where lake trout recruitment through natural reproduction has become well established, the coexistence of the two

  4. Isotope Hydrology of Arctic Tundra Lakes in a Region Impacted by Permafrost Disturbance

    NASA Astrophysics Data System (ADS)

    Peters, D. L.

    2009-05-01

    A projected "hot spot" of climate warming and development is the Mackenzie River Delta region, Northwest Territories, Canada. The upland tundra areas within the Mackenzie Gas Project development area north of Inuvik contain thousands of small lakes and ponds with poorly defined ephemeral drainage that are underlain by thick permafrost and ice-rich sediments for which the basic water balance controls are not fully understood. Natural retrogressive thaw slumps are common along lakeshores and the rapid drainage of ice-rich permafrost-dammed lakes has been occurring. Ongoing oil/gas exploration activities and infrastructure construction may result in terrain disturbance and localized degradation of permafrost, while climate change may increase the magnitude and frequency of thermokarst processes. These disturbed lakes are believed to act as historical analogues for the future effects of climate change on the hydrology, geochemistry, and aquatic ecology of small tundra lake catchments in the continuous permafrost zone of northwestern Canada. Environment Canada initiated an integrated research program in 2005 with the overall goal of improving our understanding of hydro-ecological processes in freshwater aquatic ecosystems affected by shoreline slumping vs. pristine lakes. Limited catchment studies have examined water-balance parameters (e.g., precipitation, evaporation, and surface flows) for tundra lakes in the development area. Enrichment of oxygen-18 (18O) and deuterium (2H) stable isotopes in surface waters have been shown to be useful indicators of water balance variations in remote permafrost regions of Canada where hydroclimatic information is very limited. In particular, information on evaporation: inflow (E/I) ratios and residence times would provide useful information for estimating appropriate water withdrawals from lakes within the proposed development area. A key question is "does permafrost slumping impact the hydrology of tundra lakes via catchment area

  5. Glial cell biology in the Great Lakes region.

    PubMed

    Feinstein, Douglas L; Skoff, Robert P

    2016-01-01

    We report on the tenth bi-annual Great Lakes Glial meeting, held in Traverse City, Michigan, USA, September 27-29 2015. The GLG meeting is a small conference that focuses on current research in glial cell biology. The array of functions that glial cells (astrocytes, microglia, oligodendrocytes, Schwann cells) play in health and disease is constantly increasing. Despite this diversity, GLG meetings bring together scientists with common interests, leading to a better understanding of these cells. This year's meeting included two keynote speakers who presented talks on the regulation of CNS myelination and the consequences of stress on Schwann cell biology. Twenty-two other talks were presented along with two poster sessions. Sessions covered recent findings in the areas of microglial and astrocyte activation; age-dependent changes to glial cells, Schwann cell development and pathology, and the role of stem cells in glioma and neural regeneration. PMID:27029404

  6. The 24 July 2008 outburst flood of Zyndan glacier lake, Ysyk-Köl region, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Narama, C.; Duishonakonov, M.; Kääb, A.; Abdrakhmatov, K.

    2009-04-01

    On 24 July 2008, a glacial lake outburst flood (GLOF) occurred in the Zyndan River, the Ysyk-Köl region, Kyrgyzstan. The flood killed three people and many livestock (horse, sheep, fish), and caused heavy damage destroying a bridge, road, two homes, and crops of agriculture fields. We researched the damege after two days of the GLOF. Using kinematic GPS we measured the decrease of the glacier lake area, and the according drop of the water level through the outburst. Glacier lake area of about 0.03 km2 reduced after the collapse, more than 400,000 m3 of water were discharged. While the initial flood discharge was relatively small, it increased substantially and was carrying large boulders after 30 minutes. When spreading further downstream, the dirty waters trapped eight people on islands between the stream branches. The flood discharge continued to rise until midnight and began to decrease again around 3 AM the next morning. The lake at 3771 m asl is located in front of the west Zyndan glacier at the head of the Zyndan River basin. The glacier lake had developed rapidly due to glacier shrinkage caused by recent atmospheric warming. Reasons for the outburst included melting of dead ice inside the moraine that dammed the lake. The villages downstream escaped heavy damage, because the main flood changed its direction, away from the water reservoir along the village and towards another river.

  7. Regional spatial and temporal interpolation of atmospheric PCBs: Interpretation of Lake Michigan mass balance data

    SciTech Connect

    Green, M.L.; Depinto, J.V.; Sweet, C.; Hornbuckle, K.C.

    2000-05-01

    During the Lake Michigan Mass Balance (LMMB) Project, over 600 atmospheric samples were collected at eight shoreline sites and during seven cruises. These samples were analyzed for persistent organic pollutants, including PCB congeners, atrazine, and trans-nonachlor. The authors have developed a method for interpreting the gas-phase data that includes fractionating the observed PCB concentration into land- and water-based sources. This approach accounts for differences in gas-phase atmospheric PCB concentration over water and over land. Using this fractionation approach, they have interpolated the measured data over time and space to predict PCB air concentrations over the lake during the LMMB field period. The results predict gas-phase {Sigma}PCB (sum of {approximately}98 congener groups) concentrations for each of 2,319 grid cells over the lake, on a monthly basis. The authors estimate that lake-wide monthly average {sigma}PCB gas-phase concentrations range from 0.136 to 1.158 ng/m{sup 3}, with an annual average PCB concentration of 0.457 ng/m{sup 3}. As expected, the highest concentrations of PCBs over the lake when the winds are from the southwest (out of the Chicago-Gary region) and when land surface temperatures are elevated. The predicted influence of Chicago is described on a monthly basis as a zone of elevated PCB concentrations for approximately 40 km into Lake Michigan.

  8. Glacial Isostatic Adjustment in the Great Lakes Region Inferred by Tide Gauges and Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Shum, C.; Kuo, C.; Mitrovica, J. X.

    2002-05-01

    Glacial isostatic adjustment (GIA) of the solid Earth due to deglaciation since the last Ice Age is characterized by its viscous rebound as a result of relaxation of the shear stresses inside the Earth. GIA uplift (in the form of 3-D crustal motion and the ensuing geoid change due to redistribution of mass in the solid Earth) has been recently measured with long-term GPS (e.g., the BIFROST project). In this paper, we used more than 50 long-term (1860-2000) water level gauges located around the Great Lakes, and satellite altimetry measurements (TOPEX/ POSEIDON and Geosat, 9-15 year data span) to measure the vertical motion of the region. Preliminary results indicate that Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario, are uplifting at a rate of 1.8, 0.9, 1.4, -0.5, and 1.0 mm/yr, respectively. The uncertainty of the measurement is primarily due to the error in satellite altimetry due to its relatively short data span. The results are compared with available GIA models, including ICE-4G, and Mitrovica-Milne 2001 models, as well as relative vertical motion measured using water level gauges [Manville et al., 2001]. Analysis also includes the examination of GIA models using different estimates of mantle thickness and upper and lower mantle viscosity. Results using the vertical measurement in an inverse geophysical solution will be reported.

  9. Dominant species of the gastropod fauna from the littoral region in Lake Ohrid of R. Macedonia.

    PubMed

    Smiljkov, S; Budzakoska-Gjoreska, B; Sapkarev, J; Trajanovski, S

    2007-07-01

    The class of Gastropoda is one of the Lake Ohrid' macrozoobenthic groups, which characterize highest level of endemism. Since the first published references until now, studying the Lake Ohrid's snail fauna represents huge scientific challenge for many malacologists from the world. The high percent of endemic as well as relic forms among the lake's gastropods could be explained by the processes of intralacustric speciation during the history and evolution of this aquatic ecosystem. These processes no doubt have been enabled by the complexity and stability of the Lake's basin. This work represents the results of the dominant species, from both qualitative and quantitative sense of the gastropod fauna from 19 investigated littoral localities of Lake Ohrid. The results from the investigations on gastropod fauna has shown that following species: Chilopyrgula sturanyi, Radix relicta and Valvata stenotrema quailtatively predominates in the samples from the littoral region of the Macedonian part of Lake Ohrid. The quantitative analyses (according to their presence on m2), has shown that the following species predominate: Chilopyrgula sturanyi (6879 No x m2), Theodoxus fluviatilis dalmaticus (6412 No x m2), Pyrgohydrobia grochmalickii (5504 No x m2) and Valvata stenotrema (5009 No x m2). PMID:17921924

  10. Summertime thermally-induced circulations over the Lake Nam Co region of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Yang, Xianyu; Lü, Yaqiong; Ma, Yaoming; Wen, Jun

    2015-04-01

    Performance of the fifth-generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) over the Lake Nam Co region of the Tibetan Plateau was evaluated based on the data from five surface observation sites in 2006. The interaction between two thermally-induced circulations (lake breezes and mountain-valley winds) was also investigated. The results show that MM5 could be used to simulate 2-m air temperature; however, MM5 needs improvement in wind field simulation. Two numerical simulations were conducted to study the effect of the lake on the local weather and wind system. The original land cover of the model was used in the control experiment, and the lake was replaced with grassland resembling the area surrounding the lake in the sensitive experiment. The results of the simulations indicate that the lake enhanced the north slope mountain-valley wind and the mountain changed the offshore flow direction at the north shore. During the day, a clear convergent zone and a strong upflow were observed over the north slope of the Nyainq'entanglha Range, which may cause frequent precipitation over the north slope. During the night, the entire area was controlled by a south flow.

  11. Regional patterns and local variability of dry and occult deposition strongly influence sulfate concentrations in Maine lakes

    SciTech Connect

    Norton, S.A.; Kahl, J.S.; Brakke, D.F.; Brewer, G.F.; Haines, T.A.

    1988-01-01

    There is great uncertainty and large cost in making dry deposition measurements. The authors present evidence based on wet deposition, evapotranspiration, S storage in lake sediments, and sulfate concentrations in lakes and streams in Maine that the dry deposition flux of sulfur to drainage basins of lakes in Maine ranges from nearly 0% to more than 100% of wet deposition, even in small areas. The regional pattern of sulfate concentrations in Maine lakes is due to gradients in both wet and dry deposition and variation in evapotranspiration. Patterns are modified locally by lakes hydrologic type, elevation, vegetation, and terrestrial drainage basin aspect. (Copyright (c) 1988 Elsevier Science Publishers B.V.)

  12. Digital Data for Volcano Hazards in the Crater Lake Region, Oregon

    USGS Publications Warehouse

    Schilling, S.P.; Doelger, S.; Bacon, C.R.; Mastin, L.G.; Scott, K.E.; Nathenson, M.

    2008-01-01

    Crater Lake lies in a basin, or caldera, formed by collapse of the Cascade volcano known as Mount Mazama during a violent, climactic eruption about 7,700 years ago. This event dramatically changed the character of the volcano so that many potential types of future events have no precedent there. This potentially active volcanic center is contained within Crater Lake National Park, visited by 500,000 people per year, and is adjacent to the main transportation corridor east of the Cascade Range. Because a lake is now present within the most likely site of future volcanic activity, many of the hazards at Crater Lake are different from those at most other Cascade volcanoes. Also significant are many faults near Crater Lake that clearly have been active in the recent past. These faults, and historic seismicity, indicate that damaging earthquakes can occur there in the future. The USGS Open-File Report 97-487 (Bacon and others, 1997) describes the various types of volcano and earthquake hazards in the Crater Lake area, estimates of the likelihood of future events, recommendations for mitigation, and a map of hazard zones. The geographic information system (GIS) volcano hazard data layers used to produce the Crater Lake earthquake and volcano hazard map in USGS Open-File Report 97-487 are included in this data set. USGS scientists created one GIS data layer, c_faults, that delineates these faults and one layer, cballs, that depicts the downthrown side of the faults. Additional GIS layers chazline, chaz, and chazpoly were created to show 1)the extent of pumiceous pyroclastic-flow deposits of the caldera forming Mount Mazama eruption, 2)silicic and mafic vents in the Crater Lake region, and 3)the proximal hazard zone around the caldera rim, respectively.

  13. The impact of the African Great Lakes on the regional climate in a dynamically downscaled CORDEX simulation (COSMO-CLM)

    NASA Astrophysics Data System (ADS)

    Thiery, W.; Panitz, H.; van Lipzig, N.

    2013-12-01

    Owing to the strong contrast in albedo, roughness and heat capacity between land and water, lakes significantly influence the exchange of moisture, heat and momentum between the surface and the boundary layer. To investigate this two-way interaction, a correct representation of lakes within regional climate models is essential. To this end, the one-dimensional lake parameterisation scheme FLake was recently coupled to the regional climate model COSMO-CLM (CCLM). One region where lakes constitute a key component of the climate system is the African Great Lakes region. In this study, the CCLM CORDEX-Africa evaluation simulation is dynamically downscaled from 0.44° (50 km) to 0.0625° (7 km) over East-Africa. The performance of two lake modules within CCLM are compared for the period 1999-2008: the default FLake scheme and the alternative Community Land Model. Model results are evaluated in a three-step procedure. First, the atmospheric state variables near-surface temperature, precipitation, surface energy fluxes, fractional cloud cover and column precipitable water are evaluated using in-situ based and satellite-derived products. Second, a comprehensive set of in-situ water temperature profile observations serves to evaluate the temporal evolution of water temperatures at three sites: Lake Kivu (Ishungu), Lake Tanganyika's northern basin (Kigoma) and southern basin (Mpulungu). Finally, spatial variability of surface temperatures in Lake Kivu and Lake Tanganyika are evaluated on the basis of satellite-derived lake surface temperatures. Subsequently, the preferred model configuration is used to quantify and understand effects by lakes reported for other regions in the world, such as a dampened diurnal temperature range, enhanced evaporation, modified surface layer stability, increased downwind precipitation, stronger winds, and the formation of local circulation patterns. This is achieved through comparison to a model integration excluding lake effects.

  14. Regional geoid modeling in the area of subglacial Lake Vostok, Antarctica

    NASA Astrophysics Data System (ADS)

    Schwabe, Joachim; Ewert, Heiko; Scheinert, Mirko; Dietrich, Reinhard

    2014-04-01

    We present a geoid model for the area of Lake Vostok, Antarctica, from a combination of local airborne gravity, ice-surface and ice-thickness data and a lake bathymetry model. The topography data are used for residual terrain modeling (RTM) in a remove-restore approach together with GOCE satellite data. The quasigeoid is predicted by least-squares collocation (LSC) and subsequently converted to geoid heights. Special aspects of that method in presence of an ice sheet are discussed. It is well known that a body freely floating in water is in a state of hydrostatic equilibrium (HE). This usually applies, e.g., to ice shelves or sea ice. However, it has been shown that this is valid also for the ice sheet covering the subglacial Lake Vostok. Thus, we demonstrate the use of such a refined regional geoid model for glaciological and geophysical applications by means of the HE surface of that lake. The mean quadratic residual geoid signal (0.56 m) w.r.t. the GOCE background model exceeds the residual variations of the estimated apparent lake level (ALL) (0.26 m) within the central part of the lake. An approach considering the actual geopotential at the ALL has been derived and subsequently applied. In this context, downward continuation of the potential field within the ice sheet as well as the latitudinal tilt of off-geoid equipotential surfaces are discussed. In view of the accuracy of the ice-thickness measurements that dominate the total error budget of the estimated ALL these effects are negligible. Thus, the HE surface of subglacial lakes may safely be described by a constant height bias in small-scale regional applications. However, field continuation is significant with respect to the formal uncertainty of the quasigeoid, which is at the level of 5 cm given that accurate airborne gravity data (±2 mGal) are available.

  15. Electromagnetic Surveying in the Mangrove Lakes Region of Everglades National Park

    NASA Astrophysics Data System (ADS)

    Whitman, D.; Price, R.; Frankovich, T.; Fourqurean, J.

    2015-12-01

    The Mangrove Lakes are an interconnected set of shallow (~ 1m), brackish lake and creek systems on the southern margin of the Everglades adjacent to Florida Bay. Current efforts associated with the Comprehensive Everglades Restoration Plan (CERP) aim to increase freshwater flow into this region. This study describes preliminary results of geophysical surveys in the lakes conducted to assess changes in the groundwater chemistry as part of a larger hydrologic and geochemical study in the Everglades Lakes region. Marine geophysical profiles were conducted in Alligator Creek (West Lake) and McCormick Creek systems in May, 2014. Data included marine electromagnetic (EM) profiles and soundings, water depth measurements, surface water conductivity and salinity measurements. A GSSI Profiler EMP-400 multi-frequency EM conductivity meter continuously recorded in-phase and quadrature field components at 1, 8, and 15 KHz. The system was deployed in a flat bottomed plastic kayak towed behind a motorized skiff. Lake water depths were continuously measured with a sounder/chart plotter which was calibrated with periodic sounding rod measurements. At periodic intervals during the survey, the profiling was stopped and surface water conductivity, temperature and salinity are recorded with a portable YSI probe on the tow boat. Over 40,000 discrete 3-frequency EM measurements were collected. The data were inverted to 2-layer models representing the water layer thickness and conductivity and the lake bottom conductivity. At spot locations, models were constrained with water depth soundings and surface water conductivity measurements. At other locations along the profiles, the water depth and conductivity were allowed to be free, but the free models were generally consistent with the constrained models. Multilayer sub-bottom models were also explored but were found to be poorly constrained. In West Lake, sub-bottom conductivities decreased from 400 mS/m in the west to 200 mS/m in the

  16. Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China

    NASA Astrophysics Data System (ADS)

    Wen, Zhidan; Song, Kaishan; Zhao, Ying; Jin, Xiuliang

    2016-08-01

    Understanding concentrations of carbon dioxide (CO2) and methane (CH4) in lakes is an important part of a comprehensive global carbon budget. We estimated data on the partial pressure of CO2 (pCO2) and CH4 (pCH4) from sampling with 95 lakes in semi-humid/semi-arid region of Northeastern China during ice-free period. Both pCO2 and pCH4 varied greatly among the study sites. p(CO2) values in these lakes ranged from 21.9 to 30,152.3 μatm (n = 403), and 91% of lakes in this survey were supersaturated with CO2. p(CH4) values ranged from 12.6 to 139,630.7 μatm with all sites in this study of CH4 sources to the atmosphere during the ice-free period. The collected urban lakes samples exhibited higher pCO2 and pCH4 than wild lakes samples. Either the mean value of p(CO2) or p(CH4) in saline waters is higher than in fresh waters. Correlation analysis implied that the partial pressure of the GHGs (CO2 and CH4) showed statistically correlations with water environment indicators like pH, dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chla). However, the most of the relationships showed a high degree of scatter, only pH might be used as the predictor of the gas partial pressure based on the result of this study (rpCO2 = -0.437, p < 0.01, n = 382; rpCH4 = -0.265, p < 0.01, n = 400). Furthermore, salinity could be a good predictor for p(CO2) and p(CH4) in 83 freshwater lakes in our study (rpCO2 = 0.365, rpCH4 = 0.323, p < 0.01, n = 348). The mean CO2 flux increased with the decreasing lake area size. The calculated annual areal carbon emission rate is 560.2 g C m-2 from 95 lakes in Northeastern China. We could not extrapolate carbon emission from these lakes to the boreal region or a wider scale because of the change of environmental conditions.

  17. The Professional Reading Habits of Senior Housing Officers at ACUHO-I Member Institutions in the Great Lakes Region

    ERIC Educational Resources Information Center

    O'Dell, Kyle

    2009-01-01

    This study examined the professional reading habits of Senior Housing Officers (SHOs) at ACUHO-I member institutions in the Great Lakes region, which encompasses the states of Ohio, Michigan, Illinois, and Indiana. The findings were based on data from the survey responses of SHOs at 71 colleges and universities across the Great Lakes region of the…

  18. Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

    PubMed

    Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

    2016-01-01

    Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively. PMID:26947748

  19. Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China

    PubMed Central

    Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

    2016-01-01

    Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively. PMID:26947748

  20. Water Quality in an Elevated CO2 Region: a Field Study at Mammoth Lakes, CA

    NASA Astrophysics Data System (ADS)

    Dwyer, C. D.; Ellis, A. S.; Khachikian, C.; CenterEnergy; Sustainability

    2010-12-01

    Increasing levels of anthropogenic carbon dioxide in the atmosphere have led to concern with regard to the consequences of global warming. Efforts to limit, if not prevent, further increases are becoming a great priority. Among the variety of proposed mitigation methods is that of injecting CO2 into structural reservoirs in deep permeable geologic formations. Understanding the potential side effects on the environment should leaks occur is essential to our ability to prepare and mitigate environmental hazards. This study examines the effect of elevated soil levels of CO2 on water chemistry. In more specific terms, the purpose is to find geochemical signatures to indicate that elevated CO2 is causing observable changes in water chemistry. Preliminary targets elements are Si, Al and Sr in conjunction with major ions. Mammoth Mountain provides an excellent study area as CO2 gas from an underlying magma chamber has been leaking into the overlying soil, turning it into a natural analogue to a leaking CO2 storage formation. Accelerated weathering of minerals is hypothesized to occur in concert with elevated CO2 levels. Water samples were collected from Horseshoe Lake (adjacent to a high flux of soil CO2), streams that drain into Horseshoe lake, and from Mcleod Lake (with “normal” CO2 levels). Preliminary results show that the waters of Mammoth Lakes are generally dilute, with the major inputs being snowmelt and runoff from Mammoth Mountain. Water samples from the high CO2 Horseshoe Lake area have higher alkalinity (0.295 meq/L compared to 0.047 meq/L at McLeod Lake), an indication of more weathering occurring at the high CO2 lake. Weathering from alumnosilicate minerals is one of the main sources of dissolved ions to waters in the region. Al and Si concentrations are higher in the streams (39μg/L and 4575μg/L respectively) than in the lake (16μg/L and 3074 respectively). Al/Na molar ratios in Horseshoe Lake range from 0.008 - 0.028 while stream inputs to the lake

  1. Spatial and Temporal Trends of Snowfall in Central New York - A Lake Effect Dominated Region

    NASA Astrophysics Data System (ADS)

    Hartnett, Justin Joseph

    Central New York is located in one of the snowiest regions in the United States, with the city of Syracuse, New York the snowiest metropolis in the nation. Snowfall in the region generally begins in mid-November and lasts until late-March. Snow accumulation occurs from a multitude of conditions: frontal systems, mid-latitude cyclones, Nor'easters, and most notably lake-effect storms. Lake effect snowfall (LES) is a difficult parameter to forecast due to the isolated and highly variable nature of the storm. Consequently, studies have attempted to determine changes in snowfall for lake-effect dominated regions. Annual snowfall patterns are of particular concern as seasonal snowfall totals are vital for water resources, winter businesses, agriculture, government and state agencies, and much more. Through the use of snowfall, temperature, precipitation, and location data from the National Weather Service's Cooperative Observer Program (COOP), spatial and temporal changes in snowfall for Central New York were determined. In order to determine climatic changes in snowfall, statistical analyses were performed (i.e. least squares estimation, correlations, principal component analyses, etc.) and spatial maps analyzed. Once snowfall trends were determined, factors influencing the trends were examined. Long-term snowfall trends for CNY were positive for original stations (˜0.46 +/- 0.20 in. yr -1) and homogenously filtered stations (0.23 +/- 0.20 in. yr -1). However, snowfall trends for shorter time-increments within the long-term period were not consistent, as positive, negative, and neutral trends were calculated. Regional differences in snowfall trends were observed for CNY as typical lake-effect areas (northern counties, the Tug Hill Plateau and the Southern Hills) experienced larger snowfall trends than areas less dominated by LES. Typical lake-effect months (December - February) experienced the greatest snowfall trend in CNY compared to other winter months. The

  2. A REVIEW OF THE LEECHES (ANNELIDA:HIRUDINEA) IN THE GREAT LAKES REGION

    EPA Science Inventory

    The leeches of the Great Lakes region compose a significant part of the North American freshwater fauna in numbers of species (43 taxa) and are considered biologically important as parasites and predators. This report presents the taxonomy and identification of these for the Grea...

  3. Kiswahili as Vehicle of Unity and Development in the Great Lakes Region

    ERIC Educational Resources Information Center

    Kishe, Anna M.

    2003-01-01

    This paper discusses the potentiality of Kiswahili in accelerating social, political, economic and cultural integration within the Great Lakes Region. Presently, Kiswahili is a "de facto" lingua franca spoken by almost 100 million people in the world (Ntakirutimana, 2000). This is an indication of its viability in promoting unity among people with…

  4. A REGIONAL ANALYSIS OF LAKE ACIDIFICATION TRENDS FOR THE NORTHEASTEN U.S., 1982-1994

    EPA Science Inventory

    Acidic deposition is a regional phenomenon, but its effects have traditionally been studied using site-specific, intensive monitoring. We present trends information for 36 lakes of high-to-moderate acid sensitivity (defined as acid neutralizing capacity [ANC] < 100 eq L-1),and 1...

  5. An Economic History of Indian Treaties in the Great Lakes Region

    ERIC Educational Resources Information Center

    American Indian Journal, 1978

    1978-01-01

    An attempt to do what has rarely been done in the 19th century, this article examines the actual economic resources and values associated with United States Indian treaties and agreements in the Great Lakes region (land, trade, timber, maple sugar, fish and game, water resources, military posts and roads, and annuities). (JC)

  6. WORKSHOP ON CLIMATE CHANGE AND AGRICULTURE IN THE GREAT LAKES REGION

    EPA Science Inventory

    How might a changing climate impact agricultural productivity in the Great Lakes region? How might it affect a farmer's choice of crops or economic risk? What impacts could the development of wind power have on agricultural land owners? These and other questions will be explored ...

  7. GLOBAL CHANGE RESEARCH NEWS #27: PUBLICATION OF GREAT LAKES REGIONAL ASSESSMENT

    EPA Science Inventory

    EPA's Global Change Research Program is pleased to announce the publication of the Great Lakes Regional Assessment, conducted as part of the First U.S. National Assessment. The peer-reviewed assessment report is entitled, Preparing for a Changing Climate: The Potential Consequen...

  8. Changes in the area of inland lakes in arid regions of central Asia during the past 30 years.

    PubMed

    Bai, Jie; Chen, Xi; Li, Junli; Yang, Liao; Fang, Hui

    2011-07-01

    Inland lakes are major surface water resource in arid regions of Central Asia. The area changes in these lakes have been proved to be the results of regional climate changes and recent human activities. This study aimed at investigating the area variations of the nine major lakes in Central Asia over the last 30 years. Firstly, multi-temporal Landsat imagery in 1975, 1990, 1999, and 2007 were used to delineate lake extents automatically based on Normalized Difference Water Index (NDWI) threshold segmentation, then lake area variations were detailed in three decades and the mechanism of these changes was analyzed with meteorological data and hydrological data. The results indicated that the total surface areas of these nine lakes had decreased from 91,402.06 km(2) to 46,049.23 km(2) during 1975-2007, accounting for 49.62% of their original area of 1975. Tail-end lakes in flat areas had shrunk dramatically as they were induced by both climate changes and human impacts, while alpine lakes remained relatively stable due to the small precipitation variations. With different water usage of river outlets, the variations of open lakes were more flexible than those of other two types. According to comprehensive analyses, different types of inland lakes presented different trends of area changes under the background of global warming effects in Central Asia, which showed that the increased human activities had broken the balance of water cycles in this region. PMID:20830516

  9. EO-based lake-ice cover and surface temperature products: Advancing process understanding and modeling capabilities of lake-atmosphere interactions in cold regions

    NASA Astrophysics Data System (ADS)

    Duguay, C. R.; Kheyrollah Pour, H.; Ochilov, S.

    2011-12-01

    Our ability to determine the energy and water budgets of lakes is critical to modeling high latitude weather and climate. In recent years, the proper representation of lake processes in numerical weather prediction (NWP) and regional climate (RCM) models has become a topic of much interest by the scientific community. With the increased resolution of the NWP models and RCMs, it has now become possible and necessary to improve the representation of lake-atmosphere interactions to better describe the energy exchange between the atmosphere and the lake surface. Among other lake properties, knowledge about lake surface temperature and ice-coverage is critical. These two parameters can either be obtained from observations or through simulations. Although much progress is being made with lake models, as implemented in NWP/RCM models, the assimilation of data on lake temperature and fractional ice coverage has been identified as highly desirable. Spatially and temporally consistent lake ice and lake surface temperature (LST) products are invaluable in this respect. These can be derived from Earth Observation (EO) systems. However, satellite-based products must be compared with existing lake models, as well as validated and further improved as needed, to generate lake ice and LST products for operational use by the modeling community. The European Space Agency (ESA) is supporting the international efforts coordinated by the Climate and Cryosphere (CliC) project of the World Climate Research Programme (WCRP) to exploit the use of EO technology, models and in situ data to improve the characterization of river and lake ice processes and their contribution to the Northern Hydrology system. The ESA-sponsored North Hydrology project aims to develop a portfolio of novel multi-mission geo-information products, maximizing the use of ESA satellite data, to respond to the scientific requirements of the CliC community and the operational requirements of the weather and climate

  10. Analysis of land and lake surface temperature patterns during the open water and ice growth seasons in the Great Slave Lake region, Canada, from MODIS (2002-2009)

    NASA Astrophysics Data System (ADS)

    Kheyrollah Pour, H.; Duguay, C. R.

    2010-12-01

    It is now well recognized that lakes can have a considerable influence on local and regional weather and climate. Air-water exchanges of heat and moisture have climatological implications for lakes and also the climate in the vicinity of the lakes. Temperature changes in lakes are strongly influenced by changes in seasonal air temperature. Daily temperature variations also affect the temperature of lakes, especially in the surface layers. The most practical way to obtain continuous measurements of surface temperature is by means of satellite remote sensing. In this study, satellite-derived land surface temperature (LST) products from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Earth Observing System Terra and Aqua satellite platforms are used to analyse land and lake surface temperature patterns during the open water and ice growth seasons (2002-2009) in the Great Slave Lake (GSL) region, Canada. Land and lake temperatures from MODIS are contrasted and compared with near-surface air temperature measurements obtained from two nearby weather stations (Yellowknife and Hay River). Early results show that surface water temperature on GSL is colder than the surrounding land in the first two months of the open water season (June-July). It becomes equivalent to that of land in August and then becomes warmer starting in September until spring thaw. During the winter ice growth season, the lake loses heat by conduction through the upper ice surface due to the gradient from the relatively warmer water below the ice and the colder air above the ice/snow interface. For this period, GSL remains warmer than land until spring break-up. For a few weeks, between the initiation of break-up until the lake becomes free of ice, land is warmer since spring melt proceeds more quickly on land than on GSL. Mean monthly MODIS LST values on GSL (2002-2009) are shown to vary from -21±2 (February) to 10±2 (August).

  11. Regional heat flow variations in the northern Michigan and Lake Superior region determined using the silica heat flow estimator

    USGS Publications Warehouse

    Vugrinovich, R.

    1987-01-01

    Conventional heat flow data are sparse for northern Michigan. The groundwater silica heat flow estimator expands the database sufficiently to allow regional variations in heat flow to be examined. Heat flow shows a pattern of alternating highs and lows trending ESE across the Upper Peninsula and Lake Superior. The informal names given to these features, their characteristic heat flow and inferred causes are listed: {A table is presented} The results suggest that, for the study area, regional variations in heat flow cannot be interpreted solely in terms of regional variations of the heat generation rate of basement rocks. ?? 1987.

  12. Recruitment synchrony of yellow perch (Perca flavescens, Percidae) in the Great Lakes region, 1966–2008

    USGS Publications Warehouse

    Honsey, Andrew E.; Bunnell, David; Troy, Cary D.; Fielder, David G.; Thomas, Michael V.; Knight, Carey T.; Chong, Stephen; Hook, Tomas O.

    2016-01-01

    Population-level reproductive success (recruitment) of many fish populations is characterized by high inter-annual variation and related to annual variation in key environmental factors (e.g., climate). When such environmental factors are annually correlated across broad spatial scales, spatially separated populations may display recruitment synchrony (i.e., the Moran effect). We investigated inter-annual (1966–2008) variation in yellow perch (Perca flavescens, Percidae) recruitment using 16 datasets describing populations located in four of the five Laurentian Great Lakes (Erie, Huron, Michigan, and Ontario) and Lake St. Clair. We indexed relative year class strength using catch-curve residuals for each year-class across 2–4 years and compared relative year-class strength among sampling locations. Results indicate that perch recruitment is positively synchronized across the region. In addition, the spatial scale of this synchrony appears to be broader than previous estimates for both yellow perch and freshwater fish in general. To investigate potential factors influencing relative year-class strength, we related year-class strength to regional indices of annual climatic conditions (spring-summer air temperature, winter air temperature, and spring precipitation) using data from 14 weather stations across the Great Lakes region. We found that mean spring-summer temperature is significantly positively related to recruitment success among Great Lakes yellow perch populations.

  13. Hydrogeochemical evaluation of conventional and hot dry rock geothermal resource potential in the Clear Lake region, California

    SciTech Connect

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.

    1993-05-01

    Chemistry, stable isotope, and tritium contents of thermal/mineral waters in the Clear Lake region were used to evaluate conventional and hot dry rock (HDR) geothermal potential for electrical generation. Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connate types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connate (generic) end-members. The latter end-member has enriched {delta}D as well as enriched {delta}{sup 18}O, from typical high-temperature geothermal reservoir waters. Tritium data indicate most Clear Lake region waters are mixtures of old and young fluid components. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is {le}150{degree}C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures {le}150{degree}C (except for Sulphur Bank mine). HDR technologies are probably the best way to commercially exploit the known high-temperatures existing beneath the Clear Lake region particularly within and near the main Clear Lake volcanic field.

  14. Hydraulic fracturing and the Crooked Lake Sequences: Insights gleaned from regional seismic networks

    NASA Astrophysics Data System (ADS)

    Schultz, Ryan; Stern, Virginia; Novakovic, Mark; Atkinson, Gail; Gu, Yu Jeffrey

    2015-04-01

    Within central Alberta, Canada, a new sequence of earthquakes has been recognized as of 1 December 2013 in a region of previous seismic quiescence near Crooked Lake, ~30 km west of the town of Fox Creek. We utilize a cross-correlation detection algorithm to detect more than 160 events to the end of 2014, which is temporally distinguished into five subsequences. This observation is corroborated by the uniqueness of waveforms clustered by subsequence. The Crooked Lake Sequences have come under scrutiny due to its strong temporal correlation (>99.99%) to the timing of hydraulic fracturing operations in the Duvernay Formation. We assert that individual subsequences are related to fracturing stimulation and, despite adverse initial station geometry, double-difference techniques allow us to spatially relate each cluster back to a unique horizontal well. Overall, we find that seismicity in the Crooked Lake Sequences is consistent with first-order observations of hydraulic fracturing induced seismicity.

  15. Bathymetric distribution of fish in the Apostle Islands region, Lake Superior

    USGS Publications Warehouse

    Dryer, William R.

    1966-01-01

    Records of seasonal and “all-season” (April-December) bathymetric distribution are given for 17 species of fish taken in bottom trawls and experimental gill nets fished on the bottom in 1958–63 in the Apostle Islands region of Lake Superior. The data are based on catches from 578 trawl tows at 2–59 fathoms and 301,900 linear feet of gill nets fished at 2–89 fathoms. Size of the fish varied widely among different species from the same gear and the same species from different gears. Seasonal differences in depth distribution were greatest for lake trout, bloaters, round whitefish, and older smelt, which exhibited an inshore movement in the summer and fall, and for longnose suckers, which migrated to deeper water with progress of the seasons. The all-season bathymetric distributions varied considerably among species. Round whitefish, 0- and I-group smelt, longnose suckers, ninespine sticklebacks, and johnny darters were most abundant at < 10 fathoms. Concentrations of lake trout, lake herring, lake whitefish, older smelt, trout-perch, and burbot were greatest at 10–29 fathoms. Pygmy whitefish were most common at 30–39 fathoms, bloaters and spoonhead sculpins at 40–49 fathoms, and shortjaw ciscoes, slimy sculpins, and fourhorn sculpins at 50–59 fathoms. The kiyi was most abundant at 70–79 fathoms.

  16. Regional application of the PnET-BGC model to assess historical acidification of Adirondack lakes

    NASA Astrophysics Data System (ADS)

    Zhai, Jing; Driscoll, Charles T.; Sullivan, Timothy J.; Cosby, Bernard J.

    2008-01-01

    The Adirondack region of New York has high inputs of acidic deposition and large numbers of acidic lakes. The biogeochemical model, PnET-BGC, was applied to 44 statistically representative Environmental Monitoring and Assessment Program (EMAP) lake watersheds in the Adirondacks. Model simulations help provide an understanding of historical effects of acidic deposition on soils and lake waters. Model simulations indicate that median annual concentrations of SO42- and NO3- in the 44 EMAP lakes were 15.9 μeq/L and 3.8 μeq/L, respectively, in 1850, compared to the median current measured values of 88.8 μeq/L and 20.0 μeq/L. Simulated median values of pH, acid-neutralizing capacity (ANC), and soil percent base saturation were 6.63, 67.7 μeq/L, and 12.3%, respectively, in 1850, compared to the median current measured values of 5.95, 27.8 μeq/L, and 7.9%. The estimated historical surface water acidification was greatest in lakes having low ANC below values of 100 μeq/L. This pattern of historical acidification is in agreement with a previous paleolimnological investigation.

  17. Potential Economic Impacts from Offshore Wind in the Great Lakes Region (Fact Sheet)

    SciTech Connect

    Tegen, S.; Keyser, D.

    2014-01-01

    Offshore wind is a clean, renewable source of energy and can be an economic driver in the United States. To better understand the employment opportunities and other potential regional economic impacts from offshore wind development, the U.S. Department of Energy (DOE) funded research that focuses on four regions of the country. The studies use multiple scenarios with various local job and domestic manufacturing content assumptions. Each regional study uses the new offshore wind Jobs and Economic Development Impacts (JEDI) model, developed by DOE's National Renewable Energy Laboratory. This fact sheet summarizes the potential economic impacts identified by the study for the Great Lakes region.

  18. Coupling socioeconomic and lake systems for sustainability: a conceptual analysis using Lake St. Clair region as a case study.

    PubMed

    Mavrommati, Georgia; Baustian, Melissa M; Dreelin, Erin A

    2014-04-01

    Applying sustainability at an operational level requires understanding the linkages between socioeconomic and natural systems. We identified linkages in a case study of the Lake St. Clair (LSC) region, part of the Laurentian Great Lakes system. Our research phases included: (1) investigating and revising existing coupled human and natural systems frameworks to develop a framework for this case study; (2) testing and refining the framework by hosting a 1-day stakeholder workshop and (3) creating a causal loop diagram (CLD) to illustrate the relationships among the systems' key components. With stakeholder assistance, we identified four interrelated pathways that include water use and discharge, land use, tourism and shipping that impact the ecological condition of LSC. The interrelationships between the pathways of water use and tourism are further illustrated by a CLD with several feedback loops. We suggest that this holistic approach can be applied to other case studies and inspire the development of dynamic models capable of informing decision making for sustainability. PMID:23949895

  19. Land use impacts on lake water quality in Alytus region (Lithuania)

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Laukonis, Rymvidas

    2016-04-01

    Land use has important impacts on soils, surface and ground water quality. Urban agricultural areas are an important source of pollutants, which can reach lakes through surface runoff and underground circulation. Human intervention in the landscape is one of the major causes pollution and land degradation, thus it is very important to understand the impacts of and use on environment and if they have some spatial pattern (Pereira et al., 2013, 2015; Brevik et al., 2016). The identification of the spatial pattern of lakes pollution is in Alytus area (Lithuania) is fundamental, since they provide an important range of ecosystem services to local communities, including food and recreational activities. Thus, the degradation of these environments can induce important economic losses. In this context, it is import to identify the areas with high pollutant accumulation and the environmental and human factors responsible for it. The objective of this work is to study identify the amount of some important nutrients resultant from human activities in lake water quality in Alytus region (Lithuania). Alytus region is located in southern part of Lithuania and has an approximate area of 40 km2. Inside this region we analyzed several water quality parameters of 55 lakes, including, pH, electrical conductivity (EC), suspended materials (SM), water clarity (WC) biochemical oxygen demand (BDO), total phosphorous (TP), total Nitrogen (TN), dissolved organic carbon (DOC), as other environmental variables as altitude, lake maximum deep (MD), lake area and land use according Corine land cover classification (CLC2006). Previous to data analysis, data normality and homogeneity of the variances, was assessed with the Shapiro-wilk and Leven's test, respectively. The majority of the data did not respect the Gaussian distribution and the heteroscedasticity, even after a logarithmic, and box-cox transformation. Thus, in this work we used the logarithmic transformed data to do a principal

  20. Land use impacts on lake water quality in Alytus region (Lithuania)

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Laukonis, Rymvidas

    2016-04-01

    Land use has important impacts on soils, surface and ground water quality. Urban agricultural areas are an important source of pollutants, which can reach lakes through surface runoff and underground circulation. Human intervention in the landscape is one of the major causes pollution and land degradation, thus it is very important to understand the impacts of and use on environment and if they have some spatial pattern (Pereira et al., 2013, 2015; Brevik et al., 2016). The identification of the spatial pattern of lakes pollution is in Alytus area (Lithuania) is fundamental, since they provide an important range of ecosystem services to local communities, including food and recreational activities. Thus, the degradation of these environments can induce important economic losses. In this context, it is import to identify the areas with high pollutant accumulation and the environmental and human factors responsible for it. The objective of this work is to study identify the amount of some important nutrients resultant from human activities in lake water quality in Alytus region (Lithuania). Alytus region is located in southern part of Lithuania and has an approximate area of 40 km2. Inside this region we analyzed several water quality parameters of 55 lakes, including, pH, electrical conductivity (EC), suspended materials (SM), water clarity (WC) biochemical oxygen demand (BDO), total phosphorous (TP), total Nitrogen (TN), dissolved organic carbon (DOC), as other environmental variables as altitude, lake maximum deep (MD), lake area and land use according Corine land cover classification (CLC2006). Previous to data analysis, data normality and homogeneity of the variances, was assessed with the Shapiro-wilk and Leven's test, respectively. The majority of the data did not respect the Gaussian distribution and the heteroscedasticity, even after a logarithmic, and box-cox transformation. Thus, in this work we used the logarithmic transformed data to do a principal

  1. A Preliminary Study on Geological Structure and Seismological Activity in Fuxian Lake and Neighbouring Region

    NASA Astrophysics Data System (ADS)

    Tian, Jun; Lou, Ke

    2008-06-01

    The area around the Fuxian Lake is in the west branch of the Xiaojiang faulted zone, and is one of the regions with potential seismic activities. Destructive earthquakes with magnitudes larger than 5 (with intensity grade VI) happened in the region in history, and the region was affected many times by earthquakes with magnitudes larger than 6 occurring in neighbouring regions. From the analyses of geological structure of seismology and the characteristics of the seismic activities in recent years, the Fuxian Lake and the regions nearby are possible potential locations of epicenter for magnitude 7 to 7.5 earthquakes in the future. Therefore, according to the rules and regulations stipulated in "Anti Seismic and Natural Disaster Reduction Act", "Ordinance of Anti Seismic and Natural Disaster Reduction of Yuxi City", it is suggested that Yunnan Observatory should carry out evaluation of the seismic security in its construction of the Fuxian Lake Solar Observatory in accordance with the national technical standards decribed in "Technical Specifications for Evaluation of Seismic Security at Engineering Sites"

  2. Tectonic controls on magmatism in the Geysers-Clear Lake region: Evidence from new geophysical models

    USGS Publications Warehouse

    Stanley, W.D.; Benz, H.M.; Walters, M.A.; Villasenor, A.; Rodriguez, B.D.

    1998-01-01

    In order to study magmatism and geothermal systems in The Geysers-Clear Lake region, we developed a detailed three-dimensional tomographic velocity model based on local earthquakes. This high-resolution model resolves the velocity structure of the crust in the region to depths of approximately 12 km. The most significant velocity contrasts in The Geysers-Clear Lake region occur in the steam production area, where high velocities are associated with a Quaternary granitic pluton, and in the Mount Hannah region, where low velocities occur in a 5-km-thick section of Mesozoic argillites. In addition, a more regional tomographic model was developed using traveltimes from earthquakes covering most of northern California. This regional model sampled the whole crust, but at a lower resolution than the local model. The regional model outlines low velocities at depths of 8-12 km in The Geysers-Clear Lake area, which extend eastward to the Coast Range thrust. These low velocities are inferred to be related to unmetamorphosed Mesozoic sedimentary rocks. In addition, the regional velocity model indicates high velocities in the lower crust beneath the Clear Lake volcanic field, which we interpret to be associated with mafic underplating. No large silicic magma chamber is noted in either the local or regional tomographic models. A three-dimensional gravity model also has been developed in the area of the tomographic imaging. Our gravity model demonstrates that all density contrasts can be accounted for in the upper 5-7 km of the crust. Two-dimensional magnetotelluric models of data from a regional, east-west profile indicate high resistivities associated with the granitic pluton in The Geysers production area and low resistivities in the low-velocity section of Mesozoic argillites near Mount Hannah. No indication of midcrustal magma bodies is present in the magnetotelluric data. On the basis of heat flow and geologic evidence, Holocene intrusive activity is thought to have

  3. Exploring Subglacial Lake Connectivity via Groundwater Aquifers in the Dome C Region, East Antarctica

    NASA Astrophysics Data System (ADS)

    Gooch, B. T.; Carter, S. P.; Blankenship, D. D.

    2011-12-01

    Subglacial lakes lying under the Antarctic Ice Sheet form part of a dynamic, interconnected hydraulic system. Most research exploring the nature of this system has focused on flow along the ice-bed interface, neglecting the effects of groundwater transport, as such systems are thought to lack the transmissivity necessary to accommodate the inferred meltwater volume. In the Dome C region of East Antarctica, however, inferred melt water volumes are relatively low due to proximity to the ice divide and hydraulic gradients are relatively high due to steep subglacial bedrock topography, such that groundwater flow might be viable as a dominant means of water transport. This region contains many small subglacial lakes residing in bedrock depressions of steep basal topography. Preliminary analysis of radar sounding data does not always reveal an obvious hydraulic connection between these lakes despite readily apparent sources of melt feeding these bodies. Here we test several simple models for groundwater flow, including both fractured rock and porous media systems using ice-surface and bedrock geometry inferred from radio-echo sounding data and a published map of melt rates, with the purpose of defining a region in which a groundwater system can account for the majority of the water budget. We then compare these results against maps of basal reflectivity and subglacial lake distribution, as determined from radar sounding data. Areas in which groundwater flow is the dominant process will lack basal lubrication and demonstrate low basal reflectivities, but could still contain small subglacial lakes. While not spatially extensive with respect to the ice sheet, these groundwater-dominated areas could occupy the headwaters of most glacial catchments representing a unique and relatively stable subglacial environment.

  4. A new biogeochemical model to simulate regional scale carbon emission from lakes, ponds and wetlands

    NASA Astrophysics Data System (ADS)

    Bayer, Tina; Brakebusch, Matthias; Gustafsson, Erik; Beer, Christian

    2016-04-01

    Small aquatic systems are receiving increasing attention for their role in global carbon cycling. For instance, lakes and ponds in permafrost are net emitters of carbon to the atmosphere, and their capacity to process and emit carbon is significant on a landscape scale, with a global flux of 8-103 Tg methane per year which amounts to 5%-30% of all natural methane emissions (Bastviken et al 2011). However, due to the spatial and temporal highly localised character of freshwater methane emissions, fluxes remain poorly qualified and are difficult to upscale based on field data alone. While many models exist to model carbon cycling in individual lakes and ponds, we perceived a lack of models that can work on a larger scale, over a range of latitudes, and simulate regional carbon emission from a large number of lakes, ponds and wetlands. Therefore our objective was to develop a model that can simulate carbon dioxide and methane emission from freshwaters on a regional scale. Our resulting model provides an additional tool to assess current aquatic carbon emissions as well as project future responses to changes in climatic drivers. To this effect, we have combined an existing large-scale hydrological model (the Variable Infiltration Capacity Macroscale Hydrologic Model (VIC), Liang & Lettenmaier 1994), an aquatic biogeochemical model (BALTSEM, Savchuk et al., 2012; Gustafsson et al., 2014) and developed a new methane module for lakes. The resulting new process-based biogeochemical model is designed to model aquatic carbon emission on a regional scale, and to perform well in high-latitude environments. Our model includes carbon, oxygen and nutrient cycling in lake water and sediments, primary production and methanogenesis. Results of calibration and validation of the model in two catchments (Torne-Kalix in Northern Sweden and of a large arctic river catchment) will be presented.

  5. An inventory of glacial lakes in the Third Pole region and their changes in response to global warming

    NASA Astrophysics Data System (ADS)

    Zhang, Guoqing; Yao, Tandong; Xie, Hongjie; Wang, Weicai; Yang, Wei

    2015-08-01

    No glacial lake census exists for the Third Pole region, which includes the Pamir-Hindu Kush-Karakoram-Himalayas and the Tibetan Plateau. Therefore, comprehensive information is lacking about the distribution of and changes in glacial lakes caused by current global warming conditions. In this study, the first glacial lake inventories for the Third Pole were conducted for ~ 1990, 2000, and 2010 using Landsat TM/ETM + data. Glacial lake spatial distributions, corresponding areas and temporal changes were examined. The significant results are as follows. (1) There were 4602, 4981, and 5701 glacial lakes (> 0.003 km2) covering areas of 553.9 ± 90, 581.2 ± 97, and 682.4 ± 110 km2 in ~ 1990, 2000, and 2010, respectively; these lakes are primarily located in the Brahmaputra (39%), Indus (28%), and Amu Darya (10%) basins. (2) Small lakes (< 0.2 km2) are more sensitive to climate changes. (3) Lakes closer to glaciers and at higher altitudes, particularly those connected to glacier termini, have undergone larger area changes. (4) Glacier-fed lakes are dominant in both quantity and area (> 70%) and exhibit faster expansion trends overall compared to non-glacier-fed lakes. We conclude that glacier meltwater may play a dominant role in the areal expansion of most glacial lakes in the Third Pole. In addition, the patterns of the glacier-fed lakes correspond well with warming temperature trends and negative glacier mass balance patterns. This paper presents an important database of glacial lakes and provides a basis for long-term monitoring and evaluation of outburst flood disasters primarily caused by glacial lakes in the Third Pole.

  6. An inventory of glacial lakes in the Third Pole region and their changes in response to global warming

    NASA Astrophysics Data System (ADS)

    Dai, Y.; Zhang, G.; Yao, T.; Xie, H.

    2015-12-01

    No glacial lake census exists for the Third Pole region, which includes the Pamir-Hindu Kush-Karakoram-Himalayas and the Tibetan Plateau. Therefore, comprehensive information is lacking about the distribution of and changes in glacial lakes caused by current global warming conditions. In this study, the first glacial lake inventories for the Third Pole were conducted for ~1990, 2000, and 2010 using Landsat TM/ETM+ data. Glacial lake spatial distributions, corresponding areas and temporal changes were examined. The significant results are as follows. (1) There were 4602, 4981, and 5701 glacial lakes (> 0.003 km2) covering areas of 553.9 ± 90, 581.2 ± 97, and 682.4 ± 110 km2 in ~1990, 2000, and 2010, respectively; these lakes are primarily located in the Brahmaputra (39%), Indus (28%), and Amu Darya (10%) basins. (2) Small lakes (< 0.2 km2) are more sensitive to climate changes. (3) Lakes closer to glaciers and at higher altitudes, particularly those connected to glacier termini, have undergone larger area changes. (4) Glacier-fed lakes are dominant in both quantity and area (> 70%) and exhibit faster expansion trends overall compared to non-glacier-fed lakes. We conclude that glacier meltwater may play a dominant role in the areal expansion of most glacial lakes in the Third Pole. In addition, the patterns of the glacier-fed lakes correspond well with warming temperature trends and negative glacier mass balance patterns. This paper presents an important database of glacial lakes and provides a basis for long-term monitoring and evaluation of outburst flood disasters primarily caused by glacial lakes in the Third Pole.

  7. The impact of the African Great Lakes on the regional climate in a dynamically downscaled CORDEX simulation

    NASA Astrophysics Data System (ADS)

    Thiery, Wim; Panitz, Hans-Jürgen; Davin, Edouard; van Lipzig, Nicole

    2014-05-01

    Owing to the strong contrast in albedo, roughness and heat capacity between land and water, lakes significantly influence the exchange of moisture, heat and momentum between the surface and the boundary layer. To investigate this two-way interaction, a correct representation of lakes within regional climate models is essential. To this end, the one-dimensional lake parameterisation scheme FLake was recently coupled to the regional climate model COSMO-CLM (CCLM). One region where lakes constitute a key component of the climate system is the African Great Lakes region. In this study, the CCLM CORDEX-Africa evaluation simulation is dynamically downscaled from 0.44° (50 km) to 0.0625° (7 km) over East-Africa, an unprecedented resolution for this region. The performance of different CCLM configurations are compared for the period 1999-2008: in particular, CCLM is tested for its sensitivity to the choice of the lake surface temperature description (SST, FLake, an improved version of FLake and Hostetler) and the land surface model (Terra and Community Land Model). Model results are evaluated in a three-step procedure. First, the atmospheric state variables near-surface temperature, precipitation, surface energy fluxes, fractional cloud cover and column precipitable water are evaluated using in-situ based and satellite-derived products. Second, a comprehensive set of in-situ water temperature profile observations serves to evaluate the temporal evolution of water temperatures at three sites: Lake Kivu (Ishungu), Lake Tanganyika's northern basin (Kigoma) and southern basin (Mpulungu). Finally, spatial variability of surface temperatures in Lake Kivu and Lake Tanganyika are evaluated on the basis of satellite-derived lake surface temperatures. Subsequently, the preferred model configuration is used to quantify and understand effects by lakes reported for other regions in the world, such as a dampened diurnal temperature range, enhanced evaporation, modified surface layer

  8. Methyl and total mercury in precipitation in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Hall, B. D.; Manolopoulos, H.; Hurley, J. P.; Schauer, J. J.; St. Louis, V. L.; Kenski, D.; Graydon, J.; Babiarz, C. L.; Cleckner, L. B.; Keeler, G. J.

    Methylmercury (MeHg) and total mercury (THg) concentrations were measured in precipitation collected from five US sites in the Great Lakes region: three sites on the southern shore of Lake Superior (Brule River, WI, Eagle Harbor, MI, and Tahquamenon Falls, MI), one at Isle Royale National Park (MI), and one in southern Wisconsin (Devil's Lake), between May 1997 and December 2003. MeHg and THg concentrations at these sites were compared to MeHg and THg concentrations in precipitation collected at the Experimental Lakes Area (ELA) in north-western Ontario, Canada. Detectable MeHg concentrations (>0.01 ng L -1) were found in the majority of rain and snow samples collected from all sites (range=0.01-0.85 ng L -1). In general, the lowest MeHg concentrations were observed in samples taken at Tahquamenon Falls and the ELA, and the highest MeHg concentrations in precipitation were observed in samples collected from Brule River and Eagle Harbor. Total Hg concentrations in precipitation were generally between 10 and 60 ng L -1, exceeding 60 ng L -1 in one precipitation event sampled from each of Brule River, Isle Royale, Tahquamenon Falls, and Devil's Lake. The proportion of THg that was MeHg (%MeHg), was less than 6% at all sites, with the exception of seven events at Tahquamenon Falls and two events at the ELA that were between 6% and 18% MeHg. Generally, the highest MeHg concentrations were found in low-volume precipitation events (<100 mL). At Tahquamenon Falls, meteorological analysis indicated that events with higher MeHg concentrations and %MeHg exceeding 6% were generally associated with lake effect precipitation and weak local winds.

  9. Regional nitrogen budget of the Lake Victoria Basin, East Africa: syntheses, uncertainties and perspectives

    NASA Astrophysics Data System (ADS)

    Zhou, Minghua; Brandt, Patric; Pelster, David; Rufino, Mariana C.; Robinson, Timothy; Butterbach-Bahl, Klaus

    2014-10-01

    Using the net anthropogenic nitrogen input (NANI) approach we estimated the N budget for the Lake Victoria Basin in East Africa. The NANI of the basin ranged from 887 to 3008 kg N km-2 yr-1 (mean: 1827 kg N km-2 yr-1) for the period 1995-2000. The net nitrogen release at basin level is due primarily to livestock and human consumption of feed and foods, contributing between 69% and 85%. Atmospheric oxidized N deposition contributed approximately 14% to the NANI of the Lake Victoria Basin, while either synthetic N fertilizer imports or biological N fixations only contributed less than 6% to the regional NANI. Due to the low N imports of feed and food products (<20 kg N km-2 yr-1), nitrogen release to the watershed must be derived from the mining of soil N stocks. The fraction of riverine N export to Lake Victoria accounted for 16%, which is much lower than for watersheds located in Europe and USA (25%). A significant reduction of the uncertainty of our N budget estimate for Lake Victoria Basin would be possible if better data on livestock systems and riverine N export were available. Our study indicates that at present soil N mining is the main source of nitrogen in the Lake Victoria Basin. Thus, sustainable N management requires increasing agricultural N inputs to guarantee food security and rehabilitation and protection of soils to minimize environmental costs. Moreover, to reduce N pollution of the lake, improving management of human and animal wastes needs to be carefully considered in future.

  10. Characterizing chemical transport of ozone and fine particles in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Spak, Scott N.

    This dissertation presents a science framework relevant to evaluating impacts of land use policy scenarios, energy technologies, and climate on urban and regional air quality. Emerging from collaboration with urban planners, this work provides a means for employing atmospheric chemical transport modeling to understand environmental ramifications of long-term, spatially disaggregated changes in population and automobile emissions at the census tract level, and to assess the sensitivity of these changes to densification strategies. Toward these goals, the framework is used to evaluate model skill in resolving contemporary characteristics of ozone (O3) and speciated fine particles (PM2.5) in the Great Lakes region of North America, and to quantitatively explore meteorological processes that bring about observed features of these pollutants in the region. The Great Lakes were chosen due to a population concentrated in sprawling metropolitan areas, consistently high and widespread pollutant burdens, and seasonal effects of the lakes on the atmosphere. In annual simulation at 36 km resolution, the Community Multiscale Air Quality model is evaluated using speciated PM2.5 measurements taken at regulatory monitoring networks orientated to sample urban, rural, and remote areas. Performance relative to ad-hoc regional modeling goals and prior studies is average to excellent for most species throughout the year. Both pollution episodes and seasonality are captured. The Great Lakes affect pollution seasonality: strong winds advect aerosols around the deep marine boundary layer to lower surface PM2.5 in fall and winter, while O3 over the lakes is enhanced throughout the year, driven by temperature in the cool seasons and lake breeze circulation in spring and summer. Simulations confirm observational evidence that rural and small-city sources are responsible for most regional PM2.5. Sensitivities to urban and rural reductions are of comparable magnitude on a percentage basis

  11. Geochemistry of thermal/mineral waters in the Clear Lake region, California, and implications for hot dry rock geothermal development

    SciTech Connect

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.; Mansfield, J.

    1993-02-01

    Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connote types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast, ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connote end-members. The latter end-member has enriched [delta]D as well as enriched d[sup l8]O, very different from typical high-temperature geothermal reservoir waters. Tritium data and modeling of ages indicate most Clear Lake region waters are 500 to > 10,000 yr., although mixing of old and young components is implied by the data. The age of end-member connate water is probably > 10,000 yr. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is [le] 150[degrees]C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures [le] 150[degrees]C (except for Sulphur Bank Mine). Hot dry rock technologies are the best way to commercially exploit the known high temperatures existing beneath the Clear Lake region, particularly within the main Clear Lake volcanic field.

  12. The contribution of the GRAV-D airborne gravity to geoid determination in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng; Crowley, John W.; Holmes, Simon A.; Wang, Yan-Ming

    2016-05-01

    The current official North American Vertical Datum of 1988 (NAVD 88) and the International Great Lakes Datum of 1985 (IGLD 85) will be replaced by a new geoid-based vertical datum in 2022. The Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project collects high-quality airborne gravity data to improve the quality of the gravitational model that underpins the geoid model. This paper validates the contribution of GRAV-D data in the Great Lakes region. Using the lake surface height measured by satellite altimetry as an independent data set, Global Gravity Models (GGMs) with/without the GRAV-D data are compared. The comparisons show that the improvement reaches decimeters over Lake Michigan where the historic gravity data have significant errors. Over all lakes, except Lake Erie, the GRAV-D data improve the accuracy of the gravitational model to 1-3 cm.

  13. Geologic hypotheses of Lake Tanganyika region, Zaire, drawn from ERTS imagery

    NASA Technical Reports Server (NTRS)

    Wolyce, U.; Ilunga, S.

    1974-01-01

    Based on initial work in the Lake Tanganyika area of eastern Zaire, it has been concluded that ERTS imagery is extremely useful for reconnaissance level geologic mapping and analysis in this region of the humid tropics. In particular, ERTS imagery has proven useful for recognizing and mapping regional structural units, for recognizing major structural features, and for arriving at some preliminary hypotheses about the mineral potential of the area. Results so far indicate that ERTS imagery can make a major contribution to the development of the mineral resources of the country. Research has concentrated on applications of ERTS imagery in the field of cartography, geology, forestry, hydrology and agriculture. For the work in geology, a test site was chosen in eastern Zaire on the shore of Lake Tanganyika in the vicinity of the Lukuga River. This area was selected because of its varied geology and the existence of two frames of cloud-free ERTS imagery.

  14. The regional and global significance of nitrogen removal in lakes and reservoirs

    USGS Publications Warehouse

    Harrison, J.A.; Maranger, R.J.; Alexander, R.B.; Giblin, A.E.; Jacinthe, P.-A.; Mayorga, E.; Seitzinger, S.P.; Sobota, D.J.; Wollheim, W.M.

    2009-01-01

    Human activities have greatly increased the transport of biologically available nitrogen (N) through watersheds to potentially sensitive coastal ecosystems. Lentic water bodies (lakes and reservoirs) have the potential to act as important sinks for this reactive N as it is transported across the landscape because they offer ideal conditions for N burial in sediments or permanent loss via denitrification. However, the patterns and controls on lentic N removal have not been explored in great detail at large regional to global scales. In this paper we describe, evaluate, and apply a new, spatially explicit, annual-scale, global model of lentic N removal called NiRReLa (Nitrogen Retention in Reservoirs and Lakes). The NiRReLa model incorporates small lakes and reservoirs than have been included in previous global analyses, and also allows for separate treatment and analysis of reservoirs and natural lakes. Model runs for the mid-1990s indicate that lentic systems are indeed important sinks for N and are conservatively estimated to remove 19.7 Tg N year-1 from watersheds globally. Small lakes (<50 km2) were critical in the analysis, retaining almost half (9.3 Tg N year -1) of the global total. In model runs, capacity of lakes and reservoirs to remove watershed N varied substantially at the half-degree scale (0-100%) both as a function of climate and the density of lentic systems. Although reservoirs occupy just 6% of the global lentic surface area, we estimate they retain ~33% of the total N removed by lentic systems, due to a combination of higher drainage ratios (catchment surface area:lake or reservoir surface area), higher apparent settling velocities for N, and greater average N loading rates in reservoirs than in lakes. Finally, a sensitivity analysis of NiRReLa suggests that, on-average, N removal within lentic systems will respond more strongly to changes in land use and N loading than to changes in climate at the global scale. ?? 2008 Springer Science

  15. Seismicity and Tectonics of the Lake Tahoe Basin through the Truckee, California Region

    NASA Astrophysics Data System (ADS)

    Seaman, T.; Ruhl, C. J.; Schmauder, G. C.; Smith, K. D.

    2013-12-01

    East dipping range bounding normal faults, NE-trending sinistral, and NW-trending dextral strike-slip faults of the Tahoe-Truckee, California-Nevada area define the transtensional strain environment of the Northern Walker Lane. North of Long Valley, California, the Sierran front is comprised of a series of left-stepping normal faults that terminate in the northern Lake Tahoe basin area. Directly north of Lake Tahoe, slip is transferred through the Truckee, California area and northward through a complex distribution of primarily conjugate strike-slip and minor normal fault systems. The recent identification of the Polaris fault zone extends Northern Walker Lake Belt dextral slip south of the Mohawk Valley fault zone to Truckee. The region accommodates as much as 10 mm/yr of dextral shear and has a history of M6+ earthquakes. In contrast to the general lack of background seismicity associated with major range bounding normal faults in the Tahoe region, there is abundant seismicity north of the Lake through this slip transfer zone (i.e., focal mechanisms of small magnitude earthquakes provide limited constraints on the dips of major range bounding normal faults). A NE-SW-trending zone of seismicity north of Lake Tahoe and extending into southeast Reno, Nevada, includes several M4+ strike-slip and normal faulting sequences, and numerous identifiable structures. An M4.5 (2004), M4.8 (2005), and associated general increase in seismicity in the N. Tahoe area may have been triggered by broader deformation resulting from a Moho-depth dike injection event in late 2003 (von Seggern et al., 2008). Preliminary analysis of short-period focal mechanisms reveals a change in T-axis trend from ESE west of the California-Nevada border to ENE east of the border. Focal mechanism and moment tensor solutions produce a ratio of 9/1 strike-slip to normal solutions in contrast to range bounding east dipping normal structures. Earthquake relocations display distinct lineaments of seismicity

  16. Landslide susceptibility in the Tully Valley area, Finger Lakes region, New York

    USGS Publications Warehouse

    Jager, Stefan; Wieczorek, Gerald E.

    1994-01-01

    As a consequence of a large landslide in the Tully Valley, Onondaga County, New York, an investigation was undertaken to determine the factors responsible for the landslide in order to develop a model for regional landslide susceptibility. The April 27, 1993 Tully Valley landslide occurred within glacial lake clays overlain by till and colluvium on gentle slopes of 9-12 degrees. The landslide was triggered by extreme climatic events of prolonged heavy rainfall combined with rapid melting of a winter snowpack. A photoinventory and field checking of landslides within a 415 km2 study area, including the Tully Valley, revealed small recently-active landslides and other large dormant prehistoric landslides, probably Pleistocene in age. Similar to the larger Tully Valley landslide, the smaller recently-active landslides occurred in red, glacial lake clays very likely triggered by seasonal rainfall. The large dormant landslides have been stable for long periods as evidenced by slope denudational processes that have modified the landslides. These old and ancient landslides correspond with proglacial lake levels during the Pleistocene, suggesting that either inundation or rapid drainage was responsible for triggering these landslides. A logistic regression analysis was performed within a Geographic Information System (GIS) environment to develop a model of landslide susceptibility for the Tully Valley study area. Presence of glacial clays, slope angle, and glacial lake levels were used as explanatory variables for landslide incidence. The spatial probability of landsliding, categorized as low, moderate and high, is portrayed within 90-m square cells on the susceptibility map.

  17. Paradigms and proboscideans in the southern Great Lakes region, USA

    USGS Publications Warehouse

    Saunders, J.J.; Grimm, E.C.; Widga, C.C.; Campbell, G.D.; Curry, B. Brandon; Grimley, D.A.; Hanson, P.R.; McCullum, J.P.; Oliver, J.S.; Treworgy, J.D.

    2010-01-01

    Thirteen new chronometric dates for Illinois proboscideans are considered in relation to well-dated pollen records from northeastern and central Illinois. These dates span an interval from 21,228 to 12,944 cal BP. When compared to pollen spectra, it is evident that Mammut americanum inhabited spruce (Picea) and black ash (Fraxinus nigra) forest during the B??lling-Aller??d (14,700-12,900 cal BP) and early Younger Dryas (12,900-11,650 cal BP) chronozones. Both Mammuthus jeffersonii and Mammuthus primigenius inhabited spruce dominated open-woodland during the Oldest Dryas chronozone, while M.??primigenius persisted in a forest of predominantly black ash during the Aller??d chronozone. A newly discovered specimen from Lincoln, IL, clarifies the taxonomic distinction between M. primigenius and M.??jeffersonii. Hitherto, a paradigm of proboscidean succession during the full- to late-glacial periods was based on the vegetation succession of steppe tundra-like vegetation to spruce forest to spruce-deciduous forest. The presumed proboscidean succession was that of cold, dry steppe-adapted M. primigenius succeeded by more mesic-tolerant M. jeffersonii that in turn was succeeded by the wet forest-adapted M.??americanum. Reported data do not support this view and indicate a need for re-evaluation of assumptions of proboscidean ecology and history, e.g., the environmental tolerances and habits of M.??primigenius in regions south of 55??N, and its dynamic relationship with other proboscidean taxa. ?? 2009 Elsevier Ltd and INQUA.

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

    PubMed

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

    2011-12-15

    This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. PMID:22047737

  19. Ionospheric plasma turbulence over region of 2006 Iran, 2005 Lake Tanganyika and 2010 New Britain Region earthquakes.

    NASA Astrophysics Data System (ADS)

    Kosciesza, Malgorzata; Blecki, Jan; Wronowski, Roman; Parrot, Michel

    2013-04-01

    We report the results of the observation of ELF plasma turbulence registered by DEMETER satellite in the ionosphere over epicenter region of three earthquakes. First one took place on 2nd of February 2005 in Lake Tanganyika Region with magnitude 6.9. Second was earthquake with magnitude 6.1 in Iran on 31st March 2006. The last one took place on 4th of August 2010 in New Britain Region with magnitude 7.0. Obtained results we compare with data gathered during corresponding time and region with quiet seismic conditions. To study this turbulent processes we apply Fourier, wavelet, bispectral analysis and statistical description with use of kurtosis and skewness of the electric field fluctuations. These registrations are correlated with the plasma parameters measured onboard DEMETER satellite and with geomagnetic indices.

  20. MULTIVARIATE ANALYSIS OF DIATOM ASSEMBLAGES IN STREAMS IN TWO HYDROGEOMORPHIC REGIONS WITHIN THE NORTHERN LAKES AND FOREST ECOSYSTEM

    EPA Science Inventory

    An ordination approach was used to explore relationships among macroinvertebrate, habitat and landscape variables associated with diatom assemblages in streams within the Northern Lakes and Forest Ecosystem in two different hydrogeomorphic regions (i.e. the North Shore Highlands ...

  1. Crustal Structure Beneath the Lake Ontario Region from Inverse Models of Potential Field and Seismic Data

    NASA Astrophysics Data System (ADS)

    Navarrete, L. C.; Benoit, M. H.; Ebinger, C. J.; Horowitz, F.

    2014-12-01

    The regions surrounding Lake Ontario (e.g. the Adirondack mountain region and its northern border with Canada) are among the most seismically active regions in the Eastern US. However, only scant knowledge exists of the location and geometry of faults, suture zones, or crustal thickness variations that may localize strain in the crust beneath sections of New York, Pennsylvania and Ontario. Our aim is to determine the crustal density and magnetic susceptibility contrasts (e.g., steep faults, intrusive bodies, Moho topography) which give rise to anomaly patterns and to place constraints on their geometries and locations. With a better understanding of these structures, we will examine how the distribution of the faults and steep contacts throughout the region compare with zones of active seismicity. Utilizing the North American Gravity Database, we created a profile that crosses a narrow Bouguer anomaly with steep gradients surrounded by Bouguer anomaly highs transecting the lake and extending onshore east of Rochester, subparallel to the seismically active Clarendon-Linden fault. Euler deconvolution and 'worm' analyses show that this narrow anomaly is bounded by east-dipping faults that extend to mid-crustal levels. We perform receiver function analyses of Earthscope TA stations in the region in order to constrain crustal thickness and lateral variations in Vp/Vs. These receiver functions at onshore sites in the area show complex Moho structure which partially explains our anomaly.Additionally, a vintage seismic profile coupled with the Lake Ontario bathymetry dataset was used to place constraints on sedimentary strata thicknesses and to identify structures within Proterozoic basement. Predictive models of crustal variations were created from a potential field profile, receiver functions, and a seismic profile to test interpretations. The Moho topography alone does not fully explain the short wavelength gravity anomaly, and a sedimentary basin of 3-5 km in depth is

  2. Climate Change in Africa: Impacts and Effects on the Inhabitants of the Lake Chad Region.

    NASA Astrophysics Data System (ADS)

    Abubakar, B.; Tahir, S. M.; Olisa, O.

    2009-05-01

    The Department of Energy and Climate Change defined climate as the average weather experienced over a long period. This includes temperature, wind and rainfall patterns. The climate of the Earth is not static, and has changed many times in response to a variety of natural causes. Due to human activities in emmiting green house gases has resulted the Earth to get warmed by 0.74°C over the last hundred years. Around 0.4°C of this warming has occurred since the 1970s. Climate is now one of the major phenomenon threatening lives and humanity in general since the beginning of industrial revolution. Climate exerts a profound influence on the lives of poor populations in the Lake Chad region of Africa who depend on fishing and crop cultivation for livelihood and sustenance, who are unprotected against climate-related diseases, who lacked secure access to water and food and who are vulnerable to hydro meteorological hazard. The effects of climate change on the study area are many and include diminishing resources and conflicts over the available limited water resources. The Lake Chad region is a fragile area with high climate variability and extremes of weather. As this inland water is used for domestic and agricultural purposes, salt mining, as well as transportation by Nigerians, Nigeriens, Chadian and Cameroonians, it is an area of trans-boundary water conflicts. This paper examines the part played by climate change in the decline of fishery resources and livelihood activities in the Lake Chad region. Data from field studies, structured interview and secondary sources show that fish catches and livelihood activities have declined tremendously in recent times due to several factors including overexploitation and increasing demands on the aquatic resources. Findings from the study show that droughty periods have resulted in the reduction of open lake water surface from about 25,000 km2 in 1973 to less than 2,000 km2 in the 1990s. This has led to the diminishing aquatic

  3. Trends in summer chemistry linked to productivity in lakes recovering from acid deposition in the Adirondack region of New York

    USGS Publications Warehouse

    Momen, B.; Lawrence, G.B.; Nierzwicki-Bauer, S. A.; Sutherland, J.W.; Eichler, L.W.; Harrison, J.P.; Boylen, C.W.

    2006-01-01

    The US Environmental Protection Agency established the Adirondack Effects Assessment Program (AEAP) to evaluate and monitor the status of biological communities in lakes in the Adirondack region of New York that have been adversely affected by acid deposition. This program includes chemical analysis of 30 lakes, sampled two to three times each summer. Results of trends analysis for lake chemistry and chlorophyll a (chlor a) are presented for 1994 to 2003, and a general comparison is made with recent results of the Adirondack Long-Term Monitoring (ALTM) Program, which included chemical analysis of all but two of these lakes (plus an additional 24 lakes) monthly, year-round for 1992-2004. Increases in pH were found in 25 of the 30 AEAP lakes (P < 0.05) and increases in acid-neutralizing capacity (ANC) were found in 12 of the 30 lakes (P < 0.05). Concentrations of both SO 42- and Mg 2+ decreased in 11 lakes (P < 0.05), whereas concentrations of NO 3- decreased in 20 lakes (P < 0.05). Concentrations of NH 4+ decreased in 10 lakes at a significance level of P < 0.05 and in three other lakes based on P < 0.1. Concentrations of inorganic and organic monomeric aluminum generally were below the reporting limit of 1.5 ??mol L-1, but decreases were detected in four and five lakes, respectively (P < 0.1). Concentrations of chlor a increased in seven lakes at a significance level of P < 0.05 and two lakes at a significance level of P < 0.1. A significant inverse correlation was also found between chlor a and NO 3- concentrations in nine lakes at a significance level of P < 0.05 and two lakes at a significance level of P < 0.1. Results of AEAP analysis of lake chemistry were similar to those of the ALTM Program, although decreases in SO 42- concentrations were more evident in the year-round ALTM record. Overall, the results suggest (a) a degree of chemical recovery from acidification during the summer, (b) an increase in phytoplankton productivity, and (c) a decreasing trend in

  4. A needs assessment for climate change education in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Rutherford, S.; Schneider, L. B.; Walters, H.

    2011-12-01

    The National Science Foundation funded Great Lakes Climate Change Science and Education Systemic Network project is implementing a two year planning effort to create innovative education programs to benefit the public, formal and informal educators, scientists, and journalists in the region. The current partners include Eastern Michigan University, NOAA's Great Lakes Environmental Research Lab, University of Michigan, Michigan State University, Knight Center for Environmental Journalism, Ashland University, Ann Arbor Hands-On Museum, and the College of Exploration. To create a network we are planning to bring together different stakeholders to write two white papers, one from the scientists' perspective and the other from the educators'(both formal and informal) perspective. The current partners' key personnel have produced a list of possible people/institutions to include in a stakeholder survey. Some of the key personnel developed their databases from scratch. Some used listserves, and others tried a snowball email. To identify the best strategy that will inform these various stakeholders and the public regarding the science of climate change in the Great Lakes Region, a survey was developed for each of the different stakeholders. The survey is divided into three parts: 1) questions which convey some understanding of climate science and climate change 2) demographic questions, and finally 3) questions that pertain to the professional concerns or perspectives of the various stakeholders. This survey is being used to provide the project team with a "needs assessment" from the interested members of those stakeholders. The results from this process will be summarized.

  5. Regional assessment of lake ecological states using Landsat: A classification scheme for alkaline-saline, flamingo lakes in the East African Rift Valley

    NASA Astrophysics Data System (ADS)

    Tebbs, E. J.; Remedios, J. J.; Avery, S. T.; Rowland, C. S.; Harper, D. M.

    2015-08-01

    In situ reflectance measurements and Landsat satellite imagery were combined to develop an optical classification scheme for alkaline-saline lakes in the Eastern Rift Valley. The classification allows the ecological state and consequent value, in this case to Lesser Flamingos, to be determined using Landsat satellite imagery. Lesser Flamingos depend on a network of 15 alkaline-saline lakes in East African Rift Valley, where they feed by filtering cyanobacteria and benthic diatoms from the lakes' waters. The classification developed here was based on a decision tree which used the reflectance in Landsat ETM+ bands 2-4 to assign one of six classes: low phytoplankton biomass; suspended sediment-dominated; microphytobenthos; high cyanobacterial biomass; cyanobacterial scum and bleached cyanobacterial scum. The classification accuracy was 77% when verified against in situ measurements. Classified imagery and timeseries were produced for selected lakes, which show the different ecological behaviours of these complex systems. The results have highlighted the importance to flamingos of the food resources offered by the extremely remote Lake Logipi. This study has demonstrated the potential of high spatial resolution, low spectral resolution sensors for providing ecologically valuable information at a regional scale, for alkaline-saline lakes and similar hypereutrophic inland waters.

  6. Great Lakes Regional Biomass Energy Program: Quarterly report, September 1, 1986-November 30, 1986

    SciTech Connect

    Bancroft, D.

    1987-05-01

    Stressing near-term biomass feedstock production techniques and conversion processes, the objective of the program is to increase the use of biomass energy by the public and private sectors in the Great Lakes region including Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin. The Great Lakes Regional Biomass Energy Program is divided into three separate operational programs. The first is the State Grant Program, which provides resources to the seven state energy offices in the region to increase their capabilities in biomass energy. State-specific activities and interagency programs are emphasized in the State Grant Program. The second, the Subcontractor Program, involves the letting of subcontracts to private organizations to address regional biomass issues and needs. The third is the In-House Technology Transfer Program in which Council staff develop biomass energy publications and reports. The primary activity this quarter has been information transfer. The program spearheaded an effort to reach the private sector and inform people about a wide range of biomass technologies. In one of the most successful events, 35 cheese manufacturers traveled to the South Alma Cheese Factory to see a woodburner supporting the process steam needs of the facility. In addition, 20 workshops were conducted throughout the region focusing on industrial wood combustion, municipal waste to energy incineration and short rotation forestry. 1 fig.

  7. New Approaches for the Characterization of Poorly-Exposed Tephra deposits: the Case Study of Fontana Lapilli Eruption, Nicaragua

    NASA Astrophysics Data System (ADS)

    Costantini, L.; Bonadonna, C.; Houghton, B.

    2006-12-01

    The Fontana Lapilli deposit was erupted in late Pleistocene from a vent located around Masaya volcano (Nicaragua) and represents the product of one of the largest basaltic plinian eruptions studied so far. This eruption evolved from an initial sequence of short hawaiian-strombolian pulses via a moderately explosive phase to the main series of quasi-steady plinian episodes depositing fallout beds of highly-vesicular basaltic- andesite scorias (SiO2 ~ 53 wt%). Even though a few well preserved outcrops in medial area allowed the temporal evolution of the eruption to be well constrained, the lack of deposit exposure in proximal and distal areas prevents crucial eruption parameters to be determined using standard techniques. As a result we have applied an inversion technique in combination with the forward model TEPHRA to achieve column height and total erupted mass of the main units of Fontana Lapilli eruption. The power of this technique is that input parameters are not estimated a priori as in forward modelling but it automates the process of searching for optimal parameters employing a mathematical algorithm to guide the search for the best-fit parameter set. Results on the column height well agree with field data, whereas estimation of the total erupted mass show a significant discrepancy with values obtained using standard techniques. Such a discrepancy significantly affects the estimate of other important parameters, like mass discharge rate and eruption duration. The application of inversion techniques confirms the problematic of uncertainties associated with field data often used as input factors in numerical models, suggesting that numerical solutions should be preferred to curve- fitting techniques for the determination of eruption parameters above all in cases of poor deposit exposure.

  8. Development of a regional littoral benthic macroinvertebrate multi-metric index (MMI) for lakes from the National Lakes Assessment

    EPA Science Inventory

    During the 2007 National Lakes Assessment (NLA) benthic macroinvertebrate samples were collected from the lake littoral zone. The purpose of the sampling was to assess the feasibility of a multi-metric index (MMI) to assess the condition of the littoral benthic macroinvertebrate...

  9. Projecting the Impact of Regional Land-Use Change and Water Management Policies on Lake Water Quality: An Application to Periurban Lakes and Reservoirs

    PubMed Central

    Catherine, Arnaud; Mouillot, David; Maloufi, Selma; Troussellier, Marc; Bernard, Cécile

    2013-01-01

    As the human population grows, the demand for living space and supplies of resources also increases, which may induce rapid change in land-use/land-cover (LULC) and associated pressures exerted on aquatic habitats. We propose a new approach to forecast the impact of regional land cover change and water management policies (i.e., targets in nutrient loads reduction) on lake and reservoir water eutrophication status using a model that requires minimal parameterisation compared with alternative methods. This approach was applied to a set of 48 periurban lakes located in the Ile de France region (IDF, France) to simulate catchment-scale management scenarios. Model outputs were subsequently compared to governmental agencies’ 2030 forecasts. Our model indicated that the efforts made to reduce pressure in the catchment of seepage lakes might be expected to be proportional to the gain that might be obtained, whereas drainage lakes will display little improvement until a critical level of pressure reduction is reached. The model also indicated that remediation measures, as currently planned by governmental agencies, might only have a marginal impact on improving the eutrophication status of lakes and reservoirs within the IDF region. Despite the commitment to appropriately managing the water resources in many countries, prospective tools to evaluate the potential impacts of global change on freshwater ecosystems integrity at medium to large spatial scales are lacking. This study proposes a new approach to investigate the impact of region-scale human-driven changes on lake and reservoir ecological status and could be implemented elsewhere with limited parameterisation. Issues are discussed that relate to model uncertainty and to its relevance as a tool applied to decision-making. PMID:23991066

  10. Uncertainty in the Himalayan energy–water nexus: estimating regional exposure to glacial lake outburst floods

    NASA Astrophysics Data System (ADS)

    Schwanghart, Wolfgang; Worni, Raphael; Huggel, Christian; Stoffel, Markus; Korup, Oliver

    2016-07-01

    Himalayan water resources attract a rapidly growing number of hydroelectric power projects (HPP) to satisfy Asia’s soaring energy demands. Yet HPP operating or planned in steep, glacier-fed mountain rivers face hazards of glacial lake outburst floods (GLOFs) that can damage hydropower infrastructure, alter water and sediment yields, and compromise livelihoods downstream. Detailed appraisals of such GLOF hazards are limited to case studies, however, and a more comprehensive, systematic analysis remains elusive. To this end we estimate the regional exposure of 257 Himalayan HPP to GLOFs, using a flood-wave propagation model fed by Monte Carlo-derived outburst volumes of >2300 glacial lakes. We interpret the spread of thus modeled peak discharges as a predictive uncertainty that arises mainly from outburst volumes and dam-breach rates that are difficult to assess before dams fail. With 66% of sampled HPP are on potential GLOF tracks, up to one third of these HPP could experience GLOF discharges well above local design floods, as hydropower development continues to seek higher sites closer to glacial lakes. We compute that this systematic push of HPP into headwaters effectively doubles the uncertainty about GLOF peak discharge in these locations. Peak discharges farther downstream, in contrast, are easier to predict because GLOF waves attenuate rapidly. Considering this systematic pattern of regional GLOF exposure might aid the site selection of future Himalayan HPP. Our method can augment, and help to regularly update, current hazard assessments, given that global warming is likely changing the number and size of Himalayan meltwater lakes.

  11. Distal tephrochronology in volcanic regions: Challenges and insights from Kamchatkan lake sediments

    NASA Astrophysics Data System (ADS)

    Plunkett, Gill; Coulter, Sarah E.; Ponomareva, Vera V.; Blaauw, Maarten; Klimaschewski, Andrea; Hammarlund, Dan

    2015-11-01

    Kamchatka is one of the world's most active volcanic regions and has hosted many explosive eruptions during the Holocene. These eruptions had the potential to disperse tephra over wide areas, forming time-synchronous markers wherever those tephras are found. Recent research in Kamchatka has begun to focus on the geochemical analysis of individual glass shards in order to characterise tephra layers. We have applied this approach to the study of visible tephras from three lakes - one in central and two in northern Kamchatka - with the aim of identifying key tephras and potential issues in the application of distal (> 100 km from an active volcano) tephra in volcanically complex regions. In total, 23 tephras from 22 tephra beds have been geochemically analysed, representing products from at least four volcanic systems in Kamchatka. We demonstrate that distal lake sediments in the region can yield reliable tephrostratigraphies, capturing tephra from eruptions that have the greatest potential to disperse volcanic ash beyond the region. We draw attention to issues relating to correlating and distinguishing key marker horizons from the highly active Shiveluch Volcano, namely the need to ensure inter-lab comparability of geochemical data and good chronological control of the proximal and distal tephras. Importantly, we have also extended the known distribution of two key tephra isochrons from the Ksudach volcano. Our work contributes valuable glass geochemical on data several key marker beds that will facilitate future tephra and palaeoenvironmental research within and beyond Kamchatka.

  12. Crystalline rocks of the Lake Superior region, United States. Part 1

    SciTech Connect

    Harrison, W.; Sood, M.; Flower, M.; Tisue, M.

    1983-10-01

    This report is a compendium of the available information on exposed crystalline rocks in the Lake Superior region (Wisconsin, Minnesota, and the Upper Peninsula of Michigan). The report provides background information to assist in evaluating the suitability of these crystalline rock bodies for isolating high-level radioactive waste. For each crystalline rock body or complex greater than approximately 78 km/sup 2/ (30 mi/sup 2/) in area, information is presented on size, shape, location, relative and absolute age, origin, petrography, rock structure, and geophysics. Precambrian crystalline rocks of the Lake Superior region are predominantly tonalite to granite in composition in the Archean; granodiorite and granite, with subordinate tonalite, in the early Proterozoic; and alkalic syenite, rapakivi granite, and layered gabbro-troctolite-anorthosite in the Middle Proterozoic. Vertical and horizontal movements, regional and thermal metamorphism, deformation, and intrusion are evident in the region. Based on radiometric ages, three major episodes of orogenic/igneous activity are recognized: Algoman (approx. 2650 My), Penokean (approx. 1850 My), and Keweenawan (900 to 1200 My). Anorogenic magmatism approximately 1500 My ago also played an important role, particularly in Wisconsin. References, 66 figures, 10 tables.

  13. Development stages of hazardous mountain lakes and simulation of their outbursts (Central Caucasus, Russia; Sichuan mountain region, China).

    NASA Astrophysics Data System (ADS)

    Kidyaeva, Vera; Krylenko, Inna; Chernomorets, Sergey; Petrakov, Dmitry

    2013-04-01

    The importance of mountain lakes studies is related to the increasing threat of natural disasters, associated with lake outbursts and debris flows formation, because of population growth on exposed areas. The outburst hazard has not been sufficiently researched, there is a lack of data because of the lakes inaccessibility and remote sensing data is usually not detailed enough. The main scientific topics include assessment of outburst possibility and further simulation of possible outbursts scenarios. There are two types of mountain lakes: glacial (cirque, cirque-moraine, barrier-moraine, glacial-barrier, etc.) lakes and barrier (landslide, rockfall, debris flow, etc.) lakes. The first type was studied in the Central Caucasus (Russia), and the second type - in the Sichuan mountain region (China). The group of scientists, including authors, has been monitoring glacial lakes in the Mnt. Elbrus area for more than ten years. The unique data were collected, including detailed hydrological characteristics of more than ten lakes (water level dynamics, temperature, morphometrical characteristics, water balance components, etc.). Outbursts of at least three glacial lakes were observed. Hydrological characteristics of landslide Tangjiashan Lake were collected with Chinese colleagues during field studies in 2010 and 2011 years. Analysis of the collected data was used to understand the outburst mechanisms, formation factors, dam breaking factors, development stages of mountain lakes. Statistical methods of analysis in this case can be applied with some limitations because of the lack of sufficient monitoring objects, and therefore the results has been verified by experts. All types of possible outbursts mechanisms were divided by the authors into five groups: geomorphologic (caused by changes in lake dams), seismic, or geodynamic (caused by seiches, waves from rockfalls, landslides), glacial (caused by breaks in impounding glaciers, ice floating and melting), water

  14. Geophysical observations from the South Pole region of the Antarctic Ice Sheet: Evidence for a subglacial lake?

    NASA Astrophysics Data System (ADS)

    Peters, L. E.; Anandakrishnan, S. L.; Horgan, H. J.; Voigt, D. E.; Holland, C. W.

    2007-12-01

    Radio-echo sounding and satellite altimetry observations have been used to identify a catalog of well over one hundred subglacial lakes beneath the Antarctic Ice Sheet. These lakes provide a unique laboratory for studying life in extreme environments, and may also contain paleoclimate records and ecological records that may date back as far as ~35 million years, when the Antarctic continent was ice-free. One of these lakes, which is near the South Pole (and is hereafter referred to as Lake Amundsen-Scott), is typical of many subglacial lakes in its radar signature and subglacial morphology. However, both temperature modeling and radar reflection strength modeling have cast doubts on the presence of free water at the base of the ice sheet near the South Pole. We set out to reconcile these contradictions and establish the truth behind Lake Amundsen-Scott through a series of geophysical techniques. Here we present the results of several geophysical experiments performed in the proposed Lake Amundsen- Scott region, along with temperature modeling of the local ice column. In the 2006-2007 Antarctic field season, we collected ~9 km of seismic reflection and refraction data, as well as ~15 km of ice-penetrating radar profiles, in order to characterize the firn, the local ice column, and the subglacial environment. Kinematic GPS measurements were also made to determine if basal conditions are reflected in the surface expression of the region. Our temperature modeling supports the potential for liquid water at the bed, suggesting that the base of the ice sheet is at the pressure melting point here. The amalgamation of these results will reveal whether or not Lake Amundsen-Scott truly exists, as well as determine the validity of similar lakes in the current subglacial lake inventory.

  15. Manganese reduction by microbes from oxic regions of the Lake Vanda (Antarctica) water column

    SciTech Connect

    Bratina, B.J.; Stevenson, B.S.; Schmidt, T.M.; Green, W.J.

    1998-10-01

    Depth profiles of metals in Lake Vanda, a permanently ice-covered, stratified Antarctic lake, suggest the importance of particulate manganese oxides in the scavenging, transport, and release of metals. Since manganese oxides can be solubilized by manganese-reducing bacteria, microbially mediated manganese reduction was investigated in Lake Vanda. Microbes concentrated from oxic regions of the water column, encompassing a peak of soluble manganese [Mn(II)], reduced synthetic manganese oxides (MnO{sub 2}) when incubated aerobically, Pure cultures of manganese-reducing bacteria were readily isolated from waters collected near the oxic Mn(II) peak. Based on phylogenetic analysis of the 16S rRNA gene sequence, most of the isolated manganese reducers belong to the genus Carnobacterium. Cultures of a phylogenetically representative strain of Carnobacterium reduced synthetic MnO{sub 2} in the presence of sodium azide, as was seen in field assays. Unlike anaerobes that utilize manganese oxides as terminal electron acceptors in respiration, isolates of the genus Carnobacterium reduced Mn(IV) via a diffusible compound under oxic conditions. The release of adsorbed trace metals accompanying the solubilization of manganese oxides may provide populations of Carnobacterium with a source of nutrients in this extremely oligotrophic environment.

  16. Manganese Reduction by Microbes from Oxic Regions of the Lake Vanda (Antarctica) Water Column

    PubMed Central

    Bratina, Bonnie Jo; Stevenson, Bradley S.; Green, William J.; Schmidt, Thomas M.

    1998-01-01

    Depth profiles of metals in Lake Vanda, a permanently ice-covered, stratified Antarctic lake, suggest the importance of particulate manganese oxides in the scavenging, transport, and release of metals. Since manganese oxides can be solubilized by manganese-reducing bacteria, microbially mediated manganese reduction was investigated in Lake Vanda. Microbes concentrated from oxic regions of the water column, encompassing a peak of soluble manganese [Mn(II)], reduced synthetic manganese oxides (MnO2) when incubated aerobically. Pure cultures of manganese-reducing bacteria were readily isolated from waters collected near the oxic Mn(II) peak. Based on phylogenetic analysis of the 16S rRNA gene sequence, most of the isolated manganese reducers belong to the genus Carnobacterium. Cultures of a phylogenetically representative strain of Carnobacterium reduced synthetic MnO2 in the presence of sodium azide, as was seen in field assays. Unlike anaerobes that utilize manganese oxides as terminal electron acceptors in respiration, isolates of the genus Carnobacterium reduced Mn(IV) via a diffusible compound under oxic conditions. The release of adsorbed trace metals accompanying the solubilization of manganese oxides may provide populations of Carnobacterium with a source of nutrients in this extremely oligotrophic environment. PMID:9758801

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

    NASA Astrophysics Data System (ADS)

    Wagner, B.; Vogel, H.; Zanchetta, G.; Sulpizio, R.

    2010-10-01

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

  18. Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China.

    PubMed

    Wang, Fang; Jiang, Xin; Bian, Yong-Rong; Yao, Fen-Xia; Gao, Hong-Jian; Yu, Gui-Fen; Munch, Jean Charles; Schroll, Reiner

    2007-01-01

    A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, sigmaDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by sigmaHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and alpha-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD+DDE)/DDT in soils under three land usages were: paddy field > tree land > fallow land, indicating that land usage influenced the degradation of DDT in soils. Ratios of p,p'-(DDD+DDE)/DDT > 1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes. PMID:17915688

  19. How Do the Laurentian Great Lakes Water Levels Respond to Climate Change? A Regional Climate Model Study

    NASA Astrophysics Data System (ADS)

    Bennington, V.; Notaro, M.; Vavrus, S. J.

    2012-12-01

    The Laurentian Great Lakes contain twenty percent of the world's surface freshwater. Over the past century, inter-annual water levels have fluctuated in a primarily cyclic pattern with amplitudes from 0.2 m in Lake Superior to 0.7 m in Lake Erie. These changes in water levels result in more significant changes in coastlines of the Great Lakes and alter shoreline erosion, pollutant concentrations, and shoreline habitat. As climate changes, we are interested in how lake levels will respond. Global scale climate models do not depict the Great Lakes, and thus, are unlikely to accurately capture the mechanisms impacting water levels. We utilize the Abdus Salam International Centre for Theoretical Physics Regional Climate Model 4 at 20 km horizontal resolution with an improved, explicit lake model, a groundwater module, and a channel routing model. We simulate the past regional climate (1978-present) using NCEP Reanalysis to evaluate model performance and biases. We then simulate present and future water levels using boundary conditions from the global Community Climate System Model. Model evaluation and preliminary findings for future water levels will be presented.

  20. Exploring the surface liquid and lake regions of Titan with laboratory experimentation and Cassini spacecraft data

    NASA Astrophysics Data System (ADS)

    Wasiak, Felix C.

    The surface liquids and lake regions of Titan are studied utilizing three unique techniques, the results of which are reported in this dissertation. The development of a facility to simulate the surface conditions of Titan, and to conduct experiments on samples within that facility, brings an understanding of Titan's surface not possible through observation and modeling alone. The properties of this facility are presented, including conceptual methodology, design, implementation, performance, and experimental results. The facility, the main component of which is a simulation chamber, allows for Titan temperatures of 90 - 94 K and a 1.5 bar N2 atmosphere. The sample cryogenic liquids or ice undergoing experimentation are condensed within the chamber itself. During experiments, evaporation rates are determined by directly measuring mass, while vapor concentrations are determined using a gas chromatograph fitted with a flame ionization detector. The infrared (IR) spectra of liquid and ice constituents are analyzed with a Fourier transform infrared spectroscopy spectrometer (FTIR) via a fiber optic probe, and all pertinent data is logged in a computer. With the Cassini spacecraft currently orbiting Saturn and conducting periodic close flybys of Titan, a unique opportunity exists to search for change in lake size and shorelines in the northern lake region due to the temporally spaced overlapping data coverage. The results of a Geographic Information System (GIS) approach to monitoring Titan's northern lakes for change found no discernible change in northern lake size or shorelines over a 32 month period. GIS analysis of an estuary of Kraken Mare, for synthetic aperture radar (SAR) swaths taken 47 days apart, indicate a transient feature, with implications for short-term dynamic processes. A geological characterization of Ligeia Mare, the second largest sea on Titan, was performed utilizing Cassini SAR swaths. SAR swaths were mosaicked

  1. Investigating the Seismicity and Stress Field of the Truckee -- Lake Tahoe Region, California -- Nevada

    NASA Astrophysics Data System (ADS)

    Seaman, Tyler

    The Lake Tahoe basin is located in a transtensional environment defined by east-dipping range--bounding normal faults, northeast--trending sinistral, and northwest-trending dextral strike-slip faults in the northern Walker Lane deformation belt. This region accommodates as much as 10 mm/yr of dextral shear between the Sierra Nevada and Basin and Range proper, or about 20% of Pacific-North American plate motion. There is abundant seismicity north of Lake Tahoe through the Truckee, California region as opposed to a lack of seismicity associated with the primary normal faults in the Tahoe basin (i.e., West Tahoe fault). This seismicity study is focused on the structural transition zone from north-striking east-dipping Sierran Range bounding normal faults into the northern Walker Lane right-lateral strike-slip domain. Relocations of earthquakes between 2000-2013 are performed by initially applying HYPOINVERSE mean sea level datum and station corrections to produce higher confidence absolute locations as input to HYPODD. HYPODD applies both phase and cross-correlation times for a final set of 'best' event relocations. Relocations of events in the upper brittle crust clearly align along well-imaged, often intersecting, high-angle structures of limited lateral extent. In addition, the local stress field is modeled from 679 manually determined short-period focal mechanism solutions, between 2000 and 2013, located within a fairly dense local seismic network. Short-period focal mechanisms were developed with the HASH algorithm and moment tensor solutions using long-period surface waves and the MTINV code. Resulting solutions show a 9:1 ratio of strike-slip to normal mechanisms in the transition zone study area. Stress inversions using the application SATSI (USGS Spatial And Temporal Stress Inversion) generally show a T-axis oriented primarily E-W that also rotates about 30 degrees counterclockwise, from a WNW-ESE trend to ENE-WSW, moving west to east across the California

  2. Lake Ice Cover of Shallow Lakes and Climate Interactions in Arctic Regions (1950-2011): SAR Data Analysis and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Surdu, C.; Duguay, C.; Brown, L.; Fernàndez-Prieto, D.; Samuelsson, P.

    2012-12-01

    Lake ice cover is highly correlated with climatic conditions and has, therefore, been demonstrated to be an essential indicator of climate variability and change. Recent studies have shown that the duration of the lake ice cover has decreased, mainly as a consequence of earlier thaw dates in many parts of the Northern Hemisphere over the last 50 years, mainly as a feedback to increased winter and spring air temperature. In response to projected air temperature and winter precipitation changes by climate models until the end of the 21st century, the timing, duration, and thickness of ice cover on Arctic lakes are expected to be impacted. This, in turn, will likely alter the energy, water, and bio-geochemical cycling in various regions of the Arctic. In the case of shallow tundra lakes, many of which are less than 3-m deep, warmer climate conditions could result in a smaller fraction of lakes that fully freeze to the bottom at the time of maximum winter ice thickness since thinner ice covers are predicted to develop. Shallow thermokarst lakes of the coastal plain of northern Alaska, and of other similar Arctic regions, have likely been experiencing changes in seasonal ice phenology and thickness over the last few decades but these have not yet been comprehensively documented. Analysis of a 20-year time series of ERS-1/2 synthetic aperture radar (SAR) data and numerical lake ice modeling were employed to determine the response of ice cover (thickness, freezing to bed, and phenology) on shallow lakes of the North Slope of Alaska (NSA) to climate conditions over the last three decades. New downscaled data specific to the Arctic domain (at a resolution of 0.44 degrees using ERA Interim Reanalysis as boundary condition) produced by the Rossby Centre Regional Atmospheric Climate Model (RCA4) was used to drive the Canadian Lake Ice Model (CLIMo) for the period 1950-2011. In order to assess and integrate the SAR-derived observed changes into a longer historical context, and

  3. New geophysical models related to heat sources in the geysers-clear lake region, California

    USGS Publications Warehouse

    Stanley, W.D.; Blakely, R.J.

    1993-01-01

    We present an updated view of the geological and geophysical complexities of the upper crust in The Geysers-Clear Lake region in order to provide additional information regarding local structures and possible heat sources. New models and ideal-body analysis of the gravity data, new electromagnetic sounding models, and arguments made from other geophysical data sets suggest that many of the geophysical anomalies may be significantly affected by rock-property and physical-state variations in the upper 7 km, and not just to 'magma' at greater depths. We developed the new geophysical models in order to better understand constraints on the location of magma bodies.

  4. Spatial and Temporal Patterns of Mercury Accumulation in Lacustrine Sediments Across the Laurentian Great Lakes Region

    EPA Science Inventory

    Data from 103 sediment cores from the Great Lakes and inland lakes of the Great Lakes airshed were compiled to examine and provide a synthesis of patterns of historical and recent changes in mercury (Hg) deposition. Limited data from the lower Laurentian Great Lakes shows a lega...

  5. 40 CFR 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... El Dorado County within the drainage area naturally tributary to Lake Tahoe including said Lake. Placer County—that portion of Placer County within the drainage area naturally tributary to Lake Tahoe... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Lake Tahoe Intrastate Air...

  6. 40 CFR 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... El Dorado County within the drainage area naturally tributary to Lake Tahoe including said Lake. Placer County—that portion of Placer County within the drainage area naturally tributary to Lake Tahoe... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Lake Tahoe Intrastate Air...

  7. 40 CFR 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... El Dorado County within the drainage area naturally tributary to Lake Tahoe including said Lake. Placer County—that portion of Placer County within the drainage area naturally tributary to Lake Tahoe... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Lake Tahoe Intrastate Air...

  8. 40 CFR 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... El Dorado County within the drainage area naturally tributary to Lake Tahoe including said Lake. Placer County—that portion of Placer County within the drainage area naturally tributary to Lake Tahoe... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Lake Tahoe Intrastate Air...

  9. 40 CFR 81.275 - Lake Tahoe Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... El Dorado County within the drainage area naturally tributary to Lake Tahoe including said Lake. Placer County—that portion of Placer County within the drainage area naturally tributary to Lake Tahoe... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Lake Tahoe Intrastate Air...

  10. Postglacial uplift of the eastern Gulf of Finland-Lake Ladoga region: models and observations

    NASA Astrophysics Data System (ADS)

    Amantov, Aleksey; Fjeldskaar, Willy; Amantova, Marina

    2015-04-01

    The eastern Gulf of Finland - Lake Ladoga region - is at the peripheral part of the Fennoscandian post-glacial uplift. We compared different modeling results for this region with observations, including our revision of geomorphological traces of paleo shorelevel. As in many parts of the general Baltic-White Sea bedrock lowland at the margin of the Fennoscandian Shield, the bedrock landscape was modified by glaciers, but it was also the major controlling factor for the history of glacial grows and decays. First-order landforms of this segment are: Lake Ladoga-Lake Ilmen lowland, Lembolovo High of the Karelic Isthmus and Neva-Gulf of Finland lowland. The range of the bedrock topography is close to 350 m. The landforms reflect different glacial behavior during stadials, with fast movement and strong erosion in northern Ladoga, but passive motion and accumulation around Lembolovo High. The differences influenced the ice sheet and deglaciation history. The shore level displacements in this area are slightly different than westwards in the Baltic area; the shoreline tilts are usually lower in southern-central part of the eastern Gulf of Finland-lake Ladoga region. For example, the shoreline tilts at 11 600 BP in the Baltic Ice Lake in the south-east range from 0.55 to 0.31 m/km. The slope of the Ancylus shoreline varies from 0.12 to 0.18 m/km, increasing to almost the double in the north-western area. Similarly, the Littorina shore level is tilted only 0.08 m/km, rising to 0.14 m/km in the north-west. We have used this data in our high resolution modeling involving glacial isostasy, hydro isostasy, sediment isostasy, and gravity field changes. The mopdeling is based on Earth rheology model with a low-viscosity asthenosphere of thickness less than 150 km and viscosity less than 7.0x10**19 Pa s above a mantle of viscosity 10**21 Pa s, and an effective elastic lithosphere thickness of 30-40 km (flexural rigidity 10**24 Nm). The specific uplift features in the area are

  11. Regionalization of hydrologic response in the Great Lakes basin: Considerations of temporal scales of analysis

    NASA Astrophysics Data System (ADS)

    Kult, Jonathan M.; Fry, Lauren M.; Gronewold, Andrew D.; Choi, Woonsup

    2014-11-01

    Methods for predicting streamflow in areas with limited or nonexistent measures of hydrologic response commonly rely on regionalization techniques, where knowledge pertaining to gauged watersheds is transferred to ungauged watersheds. Hydrologic response indices have frequently been employed in contemporary regionalization research related to predictions in ungauged basins. In this study, we developed regionalization models using multiple linear regression and regression tree analysis to derive relationships between hydrologic response and watershed physical characteristics for 163 watersheds in the Great Lakes basin. These models provide an empirical means for simulating runoff in ungauged basins at a monthly time step without implementation of a rainfall-runoff model. For the dependent variable in these regression models, we used monthly runoff ratio as the indicator of hydrologic response and defined it at two temporal scales: (1) treating all monthly runoff ratios as individual observations, and (2) using the mean of these monthly runoff ratios for each watershed as a representative observation. Application of the models to 62 validation watersheds throughout the Great Lakes basin indicated that model simulations were far more sensitive to the temporal characterization of hydrologic response than to the type of regression technique employed, and that models conditioned on individual monthly runoff ratios (rather than long term mean values) performed better. This finding is important in light of the increased usage of hydrologic response indices in recent regionalization studies. Models using individual observations for the dependent variable generally simulated monthly runoff with reasonable skill in the validation watersheds (median Nash-Sutcliffe efficiency = 0.53, median R2 = 0.66, median magnitude of the deviation of runoff volume = 13%). These results suggest the viability of empirical approaches to simulate runoff in ungauged basins. This finding is

  12. Integrating Climate Change Into Restoration Practices in the Great Lakes Region: Creating a "Climate-smart" Great Lakes Restoration Initiative (GLRI)

    NASA Astrophysics Data System (ADS)

    Koslow, M.; Murray, M. W.

    2010-12-01

    Stakeholders from various Great Lakes sectors such as industry, state and city, federal, non-profit and academia gathered in September of 2010 in Buffalo, New York to provide ideas and input on how to integrate climate change into actions of the United States federal agencies. The mechanism by which the National Oceanic and Atmospheric Administration (NOAA) and the Environmental Protection Agency (EPA) employ climate change adaptation actions in the Great Lakes region is the Great Lakes Restoration Initiative (GLRI). In 2010 475 million was allocated through the GLRI to NOAA and EPA for on-the-ground ecological restoration projects throughout the region and 300 million is expected for 2011. With the goal to make these restoration projects "climate-smart," stakeholders made recommendations that include: application of information from the scientific community, emergency measures to deal with climate change-related surprises, priority steps for dealing with non-climate change related issues that are to be affected by climate change and steps to deal with climate change impacts on the Great Lakes ecosystem that differ from other ecosystems.

  13. Soil occupation and atmospheric variations over Sobradinho Lake area. Part two: a regional modeling study

    NASA Astrophysics Data System (ADS)

    Correia, M. F.; da Silva Dias, M. A. F.; da Silva Aragão, M. R.

    2006-11-01

    The impact of the changes on soil cover and land use brought about by the construction of the Sobradinho Dam in the semi-arid region of the São Francisco River Hydrographic Basin is analyzed by means of a numerical model RAMS. Disregarding the influence of a large scale flow, a set of factors were responsible for the creation of a rather complex circulation system that includes mountain-valley winds, lake breeze (LB) and non-conventional circulation all induced by the surface non-homogeneous aspect. Results have demonstrated that the implementation of works of such magnitude brings about environmental changes in an area that stretches far beyond the surroundings of the reservoir. The soil cover alterations due to the ever increasing development of the area with the presence of irrigated crops in a sparsely vegetated region ( caatinga) does affect land surface characteristics, occasioning for that matter the splitting of the available energy into latent and sensible heat fluxes. LB behavior varies in accordance with atmospheric conditions and also in view of the type of vegetation found in the lake surrounding areas. Hydro availability in root zones, even under adverse atmospheric conditions (high temperature and low air humidity) brings up the high rates of evaporation and plant transpiration that contribute towards the increase of humidity and the fall of temperature in lower atmospheric layers.

  14. Lake Eyre

    Atmospheric Science Data Center

    2013-04-16

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

  15. Regional differences in size-at-age of the recovering burbot (Lota lota) population in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Madenjian, C.P.; Tost, J.

    2007-01-01

    The burbot Lota lota population in Lake Erie increased dramatically between 1995 and 2003, due mainly to control of the sea lamprey Petromyzon marinus, which began in the late 1980s. We estimated total length- and weight-at-age at capture for burbot caught in annual gillnet surveys of eastern Lake Erie during August 1994–2003. Mean total length was generally greater for burbot age 4–9 years that were caught in New York waters than in either Ontario or Pennsylvania waters of Lake Erie. Similarly, mean weight was greater for burbot at ages 4 through 6 years in New York waters than in either Ontario or Pennsylvania waters. Age-9 burbot caught in Ontario waters had greater mean weight and mean total length than did age-9 burbot caught in Pennsylvania waters. One possible explanation for greater length- and weight-at-age for New York burbot may be greater abundance of prey fishes, particularly rainbow smelt Osmerus mordax and round goby Neogobius melanostomus in New York waters. Total lengths at ages 4–10 years were generally greater for burbot caught in Lake Erie during 1994–2003 than those from published studies of other large lakes in North America that we considered, including for Lake Erie in 1946. The regional differences in size-at-age have important management ramifications, particularly because a commercial fishery targeting burbot has been considered for Ontario waters of Lake Erie.

  16. Responses of 20 lake-watersheds in the Adirondack region of New York to historical and potential future acidic deposition.

    PubMed

    Zhou, Qingtao; Driscoll, Charles T; Sullivan, Timothy J

    2015-04-01

    Critical loads (CLs) and dynamic critical loads (DCLs) are important tools to guide the protection of ecosystems from air pollution. In order to quantify decreases in acidic deposition necessary to protect sensitive aquatic species, we calculated CLs and DCLs of sulfate (SO4(2-))+nitrate (NO3-) for 20 lake-watersheds from the Adirondack region of New York using the dynamic model, PnET-BGC. We evaluated lake water chemistry and fish and total zooplankton species richness in response to historical acidic deposition and under future deposition scenarios. The model performed well in simulating measured chemistry of Adirondack lakes. Current deposition of SO4(2-)+NO3-, calcium (Ca2+) weathering rate and lake acid neutralizing capacity (ANC) in 1850 were related to the extent of historical acidification (1850-2008). Changes in lake Al3+ concentrations since the onset of acidic deposition were also related to Ca2+ weathering rate and ANC in 1850. Lake ANC and fish and total zooplankton species richness were projected to increase under hypothetical decreases in future deposition. However, model projections suggest that lake ecosystems will not achieve complete chemical and biological recovery in the future. PMID:25544337

  17. Long-term recovery of lakes in the Adirondack region of New York to decreases in acidic deposition

    NASA Astrophysics Data System (ADS)

    Waller, Kristin; Driscoll, Charles; Lynch, Jason; Newcomb, Dani; Roy, Karen

    2012-01-01

    After years of adverse impacts to the acid-sensitive ecosystems of the eastern United States, the Acid Rain Program and Nitrogen Budget Program were developed to control sulfur dioxide (SO 2) and nitrogen oxide (NO x) emissions through market-based cap and trade systems. We used data from the National Atmospheric Deposition Program's National Trends Network (NTN) and the U.S. EPA Temporally Integrated Monitoring of Ecosystems (TIME) program to evaluate the response of lake-watersheds in the Adirondack region of New York to changes in emissions of sulfur dioxide and nitrogen oxides resulting from the Acid Rain Program and the Nitrogen Budget Program. TIME is a long-term monitoring program designed to sample statistically selected subpopulations of lakes and streams across the eastern U.S. to quantify regional trends in surface water chemistry due to changes in atmospheric deposition. Decreases in wet sulfate deposition for the TIME lake-watersheds from 1991 to 2007 (-1.04 meq m -2-yr) generally corresponded with decreases in estimated lake sulfate flux (-1.46 ± 0.72 meq m -2-yr), suggesting declines in lake sulfate were largely driven by decreases in atmospheric deposition. Decreases in lake sulfate and to a lesser extent nitrate have generally coincided with increases in acid neutralizing capacity (ANC) resulting in shifts in lakes among ANC sensitivity classes. The percentage of acidic Adirondack lakes (ANC <0 μeq L -1) decreased from 15.5% (284 lakes) to 8.3% (152 lakes) since the implementation of the Acid Rain Program and the Nitrogen Budget Program. Two measures of ANC were considered in our analysis: ANC determined directly by Gran plot analysis (ANC G) and ANC calculated by major ion chemistry (ANC calc = CB - CA). While these two metrics should theoretically show similar responses, ANC calc (+2.03 μeq L -1-yr) increased at more than twice the rate as ANC G (+0.76 μeq L -1-yr). This discrepancy has important implications for assessments of lake recovery

  18. Regional trends in mercury distribution across the Great Lakes states, north central USA

    NASA Astrophysics Data System (ADS)

    Nater, Edward A.; Grigal, David F.

    1992-07-01

    CONCENTRATIONS of mercury in the environment are increasing as a result of human activities, notably fossil-fuel burning and incineration of municipal wastes. Increasing levels of mercury in aquatic environments and consequently in fish populations are recognized as a public-health problem1,2. Enhanced mercury concentrations in lake sediments relative to pre-industrial values have also been attributed to anthropogenic pollution. It is generally assumed that atmospheric mercury deposition is dominated by global-scale processes, consequently being regionally uniform. Here, to the contrary, we report a significant gradient in concentrations and total amounts of mercury in organic litter and surface mineral soil along a transect of forested sites across the north central United States from northwestern Minnesota to eastern Michigan. This gradient is accompanied by parallel changes in wet sulphate deposition and human activity along the transect, suggesting that the regional variation in mercury content is due to deposition of anthropogenic mercury, most probably in particulate form.

  19. Housing Archetype Analysis for Home Energy-Efficient Retrofit in the Great Lakes Region

    SciTech Connect

    Kim, S. -K.; Mrozowski, T.; Harrell-Seyburn, A.; Ehrlich, N.; Hembroff, L.; Lieburn, B.; Mazor, M.; McIntyre, A.; Mutton, C.; Parsons, G.; Syal, M. G.; Wilkinson, R.

    2014-09-01

    This project report details activities and results of the "Market Characterization" project undertaken by the Cost Effective Energy Retrofit (CEER) team targeted toward the DOE goal of achieving 30%-50% reduction in existing building energy use. CEER consists of members from the Dow Chemical Company, Michigan State University, Ferris State University, and Habitat for Humanity Kent County. The purpose of this market characterization project was to identify housing archetypes which are dominant within the Great Lakes region and therefore offer significant potential for energy-efficient retrofit research and implementation due to the substantial number of homes possessing similar characteristics. Understanding the characteristics of housing groups referred to as "archetypes" by vintage, style, and construction characteristics can allow research teams to focus their retrofit research and develop prescriptive solutions for those structure types which are prevalent and offer high potential uptake within a region or market.

  20. Regional maximum rainfall analysis using L-moments at the Titicaca Lake drainage, Peru

    NASA Astrophysics Data System (ADS)

    Fernández-Palomino, Carlos Antonio; Lavado-Casimiro, Waldo Sven

    2016-07-01

    The present study investigates the application of the index flood L-moments-based regional frequency analysis procedure (RFA-LM) to the annual maximum 24-h rainfall (AM) of 33 rainfall gauge stations (RGs) to estimate rainfall quantiles at the Titicaca Lake drainage (TL). The study region was chosen because it is characterised by common floods that affect agricultural production and infrastructure. First, detailed quality analyses and verification of the RFA-LM assumptions were conducted. For this purpose, different tests for outlier verification, homogeneity, stationarity, and serial independence were employed. Then, the application of RFA-LM procedure allowed us to consider the TL as a single, hydrologically homogeneous region, in terms of its maximum rainfall frequency. That is, this region can be modelled by a generalised normal (GNO) distribution, chosen according to the Z test for goodness-of-fit, L-moments (LM) ratio diagram, and an additional evaluation of the precision of the regional growth curve. Due to the low density of RG in the TL, it was important to produce maps of the AM design quantiles estimated using RFA-LM. Therefore, the ordinary Kriging interpolation (OK) technique was used. These maps will be a useful tool for determining the different AM quantiles at any point of interest for hydrologists in the region.

  1. Impact of regional meteorology on ozone levels in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Rayne, Sandra; Gertler, Alan; Zielinska, Barbara; Bytnerowicz, Andrzej; Burley, Joel; Kaplan, Michael

    2016-07-01

    The Lake Tahoe Basin is located on the California-Nevada border and occasionally experiences elevated levels of ozone (O3) exceeding the California Air Resources Board ambient air quality standard (8-h average). Previous studies indicate that both the local generation and long-range transport from out-of-basin sources are important in contributing to O3 exceedances, but little is known about the impact of regional meteorology on O3 source regions. To develop a better understanding of the factors affecting O3 levels and sources in the Lake Tahoe Basin, a comprehensive field study was performed in the summer of 2010. Included in this effort was a meteorological analysis addressing potential regional meteorological influences leading to periods of elevated levels of O3. Three approaches were used to conduct the analysis: (1) regional atmospheric pressure difference (i.e., the Washoe Zephyr) to access potential transport, (2) back trajectory modeling using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine where the air masses originated and, (3) composite soundings to evaluate in-Basin atmospheric influences. These analyses indicate the Washoe Zephyr did not strongly impact O3 levels; however, higher O3 levels were found to correspond with both a more southerly wind component and a dip in dew point temperature around 400 hPa. The results also indicate that if transport does occur, it is more likely to come from the San Joaquin Valley and move to the southern part of the Basin, rather than originating in the large cities to the west (i.e., Sacramento and San Francisco).

  2. An evaluation of processes regulating spatial and temporal patterns in lake sulfate in the Adirondack region of New York

    NASA Astrophysics Data System (ADS)

    Chen, Limin; Driscoll, Charles T.

    2004-09-01

    As a result of the Clean Air Act Amendments of 1970 and 1990, there have been significant decreases in sulfate (SO42-) concentrations in surface waters across the northeastern United States. The 37 Direct/Delayed Response Program (DDRP) watersheds in the Adirondacks receive elevated levels of atmospheric S deposition and showed considerable variability in lake SO42- concentrations. In response to decreases in atmospheric S deposition, these sites have generally exhibited relatively uniform decreases in surface water SO42- concentrations. In this study, an integrated biogeochemical model (PnET-BGC) was used to simulate the response of lake SO42- concentrations at these DDRP sites to recent changes in atmospheric S deposition. Using default parameters and algorithms, the model underpredicted lake SO42- concentrations at sites with high SO42- concentrations and overpredicted at sites with low SO42- concentrations. Initial predictions of lake SO42- were relatively uniform across the region. Initial model simulations also underpredicted decreases in lake SO42- concentrations from 1984 to 2001. We identified seven hypotheses that might explain the discrepancies between model predictions and the measured data. Model inputs, parameters, and algorithms were modified to help test these hypotheses and better understand factors that control spatial and temporal patterns in lake SO42- in this acid-sensitive region.

  3. Neural network modeling for regional hazard assessment of debris flow in Lake Qionghai Watershed, China

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Guo, H. C.; Zou, R.; Wang, L. J.

    2006-04-01

    This paper presents a neural network (NN) based model to assess the regional hazard degree of debris flows in Lake Qionghai Watershed, China. The NN model was used as an alternative for the more conventional linear model MFCAM (multi-factor composite assessment model) in order to effectively handle the nonlinearity and uncertainty inherent in the debris flow hazard analysis. The NN model was configured using a three layer structure with eight input nodes and one output node, and the number of nodes in the hidden layer was determined through an iterative process of varying the number of nodes in the hidden layer until an optimal performance was achieved. The eight variables used to represent the eight input nodes include density of debris flow gully, degree of weathering of rocks, active fault density, area percentage of slope land greater than 25° of the total land (APL25), frequency of flooding hazards, average covariance of monthly precipitation by 10 years (ACMP10), average days with rainfall >25 mm by 10 years (25D10Y), and percentage of cultivated land with slope land greater than 25° of the total cultivated land (PCL25). The output node represents the hazard-degree ranks (HDR). The model was trained with the 35 sets of data obtained from previous researches reported in literatures, and an explicit uncertainty analysis was undertaken to address the uncertainty in model training and prediction. Before the NN model is extrapolated to Lake Qionghai Watershed, a validation case, different from the above data, is conducted. In addition, the performances of the NN model and the MFCAM were compared. The NN model predicted that the HDRs of the five sub-watersheds in the Lake Qionghai Watershed were IV, IV, III, III, and IV V, indicating that the study area covers normal hazard and severe hazard areas. Based on the NN model results, debris flow management and economic development strategies in the study are proposed for each sub-watershed.

  4. CO2 and CH4 emissions from streams in a lake-rich landscape: Patterns, controls, and regional significance

    NASA Astrophysics Data System (ADS)

    Crawford, John T.; Lottig, Noah R.; Stanley, Emily H.; Walker, John F.; Hanson, Paul C.; Finlay, Jacques C.; Striegl, Robert G.

    2014-03-01

    Aquatic ecosystems are important components of landscape carbon budgets. In lake-rich landscapes, both lakes and streams may be important sources of carbon gases (CO2 and CH4) to the atmosphere, but the processes that control gas concentrations and emissions in these interconnected landscapes have not been adequately addressed. We use multiple data sets that vary in their spatial and temporal extent during 2001-2012 to investigate the carbon gas source strength of streams in a lake-rich landscape and to determine the contribution of lakes, metabolism, and groundwater to stream CO2 and CH4. We show that streams emit roughly the same mass of CO2 (23.4 Gg C yr-1; 0.49 mol CO2 m-2 d-1) as lakes at a regional scale (27 Gg C yr-1) and that stream CH4 emissions (189 Mg C yr-1; 8.46 mmol CH4 m-2 d-1) are an important component of the regional greenhouse gas balance. Gas transfer velocity variability (range = 0.34 to 13.5 m d-1) contributed to the variability of gas flux in this landscape. Groundwater inputs and in-stream metabolism control stream gas supersaturation at the landscape scale, while carbon cycling in lakes and deep groundwaters does not control downstream gas emissions. Our results indicate the need to consider connectivity of all aquatic ecosystems (lakes, streams, wetlands, and groundwater) in lake-rich landscapes and their connections with the terrestrial environment in order to understand the full nature of the carbon cycle.

  5. [Land Use Pattern Change and Regional Sustainability Evaluation of Wetland in Jiaogang Lake].

    PubMed

    Yang, Yang; Cai, Yi-min; Bai, Yan-ying; Chen, Wei-ping; Yang, Xiu-chao

    2015-06-01

    Changes in land use and sustainability evaluation of wetland in Jiaogang Lake from 1995 to 2013 were analyzed, based on the land use change models and an index system, supported by RS, GIS, and social statistical data. The results showed: (1) dry land, paddy field, and building land were the predominant landscape in the study area. The arable land was mainly converted during 1995-2000, which was driven by the extension of agriculture, and the building land increased significantly during 2010-2013, which was driven by the tourism development. (2) Compared to the beginning research area, the building land increased by 123.3%, and the wetland decreased by 23.15%. The land system was at risk for a low proportion of wetland, scarcity of unused land, and the fragmented landscape. (3) The regional sustainability results were bad level, bad level, poor level, good level, and poor level during the different periods, with some room for improvement. (4) The fitness of regional sustainability in study area yielded satisfactory results in 2010, owing to the rapid growth of regional productivity and the regional stability. Since 2010, with the increasing environmental load, the regional sustainability fell down to the poor level. The obstruction of sustainable development is necessary to be addressed in the study area. PMID:26387342

  6. NREL/SCE High-Penetration PV Integration Project: Report on Field Demonstration of Advanced Inverter Functionality in Fontana, CA

    SciTech Connect

    Mather, B.

    2014-08-01

    The National Renewable Energy Laboratory/Southern California Edison High-Penetration PV Integration Project is (1) researching the distribution system level impacts of high-penetration photovoltaic (PV) integration, (2) determining mitigation methods to reduce or eliminate those impacts, and (3) seeking to demonstrate these mitigation methods on actual high-penetration PV distribution circuits. This report describes a field demonstration completed during the fall of 2013 on the Fontana, California, study circuit, which includes a total of 4.5 MW of interconnected utility-scale rooftop PV systems. The demonstration included operating a 2-MW PV system at an off-unity power factor that had been determined during previously completed distribution system modeling and PV impact assessment analyses. Data on the distribution circuit and PV system operations were collected during the 2-week demonstration period. This demonstration reinforces the findings of previous laboratory testing that showed that utility-scale PV inverters are capable of operating at off-unity power factor to mitigate PV impacts; however, because of difficulties setting and retaining PV inverter power factor set points during the field demonstration, it was not possible to demonstrate the effectiveness of off-unity power factor operation to mitigate the voltage impacts of high-penetration PV integration. Lessons learned from this field demonstration are presented to inform future field demonstration efforts.

  7. Mapping lake level changes using ICESat/GLAS satellite laser altimetry data: a case study in arid regions of central Asia

    NASA Astrophysics Data System (ADS)

    Li, JunLi; Fang, Hui; Yang, Liao

    2011-12-01

    Lakes in arid regions of Central Asia act as essential components of regional water cycles, providing sparse but valuable water resource for the fragile ecological environments and human lives. Lakes in Central Asia are sensitive to climate change and human activities, and great changes have been found since 1960s. Mapping and monitoring these inland lakes would improve our understanding of mechanism of lake dynamics and climatic impacts. ICESat/GLAS satellite laser altimetry provides an efficient tool of continuously measuring lake levels in these poorly surveyed remote areas. An automated mapping scheme of lake level changes is developed based on GLAS altimetry products, and the spatial and temporal characteristics of 9 typical lakes in Central Asia are analyzed to validate the level accuracies. The results show that ICESat/GLAS has a good performance of lake level monitoring, whose patterns of level changes are the same as those of field observation, and the max differences between GLAS and field data is 3cm. Based on the results, it is obvious that alpine lakes are increasing greatly in lake levels during 2003-2009 due to climate change, while open lakes with dams and plain endorheic lakes decrease dramatically in water levels due to human activities, which reveals the overexploitation of water resource in Central Asia.

  8. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years

    PubMed Central

    Han, Y. M.; Wei, C.; Huang, R.-J.; Bandowe, B. A. M.; Ho, S. S. H.; Cao, J. J.; Jin, Z. D.; Xu, B. Q.; Gao, S. P.; Tie, X. X.; An, Z. S.; Wilcke, W.

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People’s Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980–2012 relative to the period 1850–1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas. PMID:26750586

  9. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years.

    PubMed

    Han, Y M; Wei, C; Huang, R-J; Bandowe, B A M; Ho, S S H; Cao, J J; Jin, Z D; Xu, B Q; Gao, S P; Tie, X X; An, Z S; Wilcke, W

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People's Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980-2012 relative to the period 1850-1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas. PMID:26750586

  10. Ancient Tree Ring Archives in the U.S. Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Panyushkina, Irina P.; Leavitt, Steven W.

    2010-12-01

    Rather than being a seamless transition from Late Glacial Maximum to the start of the Holocene between 15,000 and 8000 years ago, the warming during this period was punctuated by abrupt climatic instabilities. These include the Younger Dryas cold event, the Preboreal Oscillation, and an isolated cooling event around 8200 years ago (see Figure 1, bottom right). In the Great Lakes area the terrestrial fingerprints of these events are often present in pollen records, yet even greater details of the environmental course of deglaciation during the Holocene transition could be gleaned with high-resolution tree ring proxies. A campaign is under way to locate, sample, and analyze tree rings of surprisingly abundant subfossil wood preserved in the Great Lakes area to improve understanding of past (and possibly future) abrupt climate change in a region where these events may have even been triggered (e.g., by glacial meltwater discharge [Murton et al., 2010]) and where early human and megafauna populations were likely profoundly affected.

  11. Reconstruction of atmospheric soot history in inland regions from lake sediments over the past 150 years

    NASA Astrophysics Data System (ADS)

    Han, Y. M.; Wei, C.; Huang, R.-J.; Bandowe, B. A. M.; Ho, S. S. H.; Cao, J. J.; Jin, Z. D.; Xu, B. Q.; Gao, S. P.; Tie, X. X.; An, Z. S.; Wilcke, W.

    2016-01-01

    Historical reconstruction of atmospheric black carbon (BC, in the form of char and soot) is still constrained for inland areas. Here we determined and compared the past 150-yr records of BC and polycyclic aromatic compounds (PACs) in sediments from two representative lakes, Huguangyan (HGY) and Chaohu (CH), in eastern China. HGY only receives atmospheric deposition while CH is influenced by riverine input. BC, char, and soot have similar vertical concentration profiles as PACs in both lakes. Abrupt increases in concentrations and mass accumulation rates (MARs) of soot have mainly occurred since ~1950, the establishment of the People’s Republic of China, when energy usage changed to more fossil fuel contributions reflected by the variations in the concentration ratios of char/soot and individual PACs. In HGY, soot MARs increased by ~7.7 times in the period 1980-2012 relative to the period 1850-1950. Similar increases (~6.7 times) were observed in CH. The increase in soot MARs is also in line with the emission inventory records in the literature and the fact that the submicrometer-sized soot particles can be dispersed regionally. The study provides an alternative method to reconstruct the atmospheric soot history in populated inland areas.

  12. Mysis diluviana and Hemimysis anomala: reviewing the roles of a native and invasive mysid in the Laurentian Great Lakes region

    USGS Publications Warehouse

    Walsh, Maureen G.; Boscarino, Brent T.; Marty, Jérôme; Johannsson, Ora E.

    2012-01-01

    Mysis diluviana and Hemimysis anomala are the only two species of mysid shrimps in the order Mysidacea that are present in the Laurentian Great Lakes of North America. M. diluviana has inhabited the deep, cold waters of this region since Pleistocene-era glacial retreat and is widely considered to have a central role in the functioning of offshore food webs in systems they inhabit. More recently, the Great Lakes were invaded by the Ponto-Caspian native Hemimysis, a species that inhabits warmer water and shallower depths relative to M. diluviana. Hemimysis has rapidly expanded throughout the Great Lakes region and has become integrated into nearshore food webs as both food for planktivorous fish and predators and competitors of zooplankton. This special issue is composed of 14 papers that represent the most recent advances in our understanding of the ecological importance of both species of mysids to lake and river ecosystems in the Great Lakes region of North America. Topics discussed in this special issue will inform future research in all systems influenced by mysid ecology.

  13. Habitat Capacity for Cougar Recolonization in the Upper Great Lakes Region

    PubMed Central

    O′Neil, Shawn T.; Rahn, Kasey C.; Bump, Joseph K.

    2014-01-01

    Background Recent findings indicate that cougars (Puma concolor) are expanding their range into the midwestern United States. Confirmed reports of cougar in Michigan, Minnesota, and Wisconsin have increased dramatically in frequency during the last five years, leading to speculation that cougars may re-establish in the Upper Great Lakes (UGL) region, USA. Recent work showed favorable cougar habitat in northeastern Minnesota, suggesting that the northern forested regions of Michigan and Wisconsin may have similar potential. Recolonization of cougars in the UGL states would have important ecological, social, and political impacts that will require effective management. Methodology/Principal Findings Using Geographic Information Systems (GIS), we extended a cougar habitat model to Michigan and Wisconsin and incorporated primary prey densities to estimate the capacity of the region to support cougars. Results suggest that approximately 39% (>58,000 km2) of the study area could support cougars, and that there is potential for a population of approximately 500 or more animals. An exploratory validation of this habitat model revealed strong association with 58 verified cougar locations occurring in the study area between 2008 and 2013. Conclusions/Significance Spatially explicit information derived from this study could potentially lead to estimation of a viable population, delineation of possible cougar-human conflict areas, and the targeting of site locations for current monitoring. Understanding predator-prey interactions, interspecific competition, and human-wildlife relationships is becoming increasingly critical as top carnivores continue to recolonize the UGL region. PMID:25389761

  14. Characteristics of nitrate horizontal transport in a paddy field of the Tai Lake region, China.

    PubMed

    Chen, X M; Shen, Q R; Pan, G X; Liu, Z P

    2003-02-01

    The characteristics of nitrate horizontal transport in a major paddy soil, Wu Shan soil in the Tai Lake region, were studied. The concentration of nitrate during horizontal movement decreased with the increasing in distance from the tracer source, the change following a logarithmic function. The concentration of the nitrate was strongly correlated with the soil moisture content, as an exponential function. The horizontal transport velocity of nitrate was significantly correlated with the distance of the tracer source as power function. Therefore, the velocity of nitrate horizontal transport was controlled by the concentration gradient of nitrate, and soil water potential gradient from beginning to the 20 cm mark in the horizontal column. However, the velocity of nitrate horizontal was stable beyond 20 cm, where it was controlled by soil matric potential. PMID:12688479

  15. HELIOTHERMAL LAKE MODEL OF BORATE DEPOSITION IN THE MIOCENE FURNACE CREEK FORMATION, DEATH VALLEY REGION, CALIFORNIA.

    USGS Publications Warehouse

    Barker, Charles E.; Barker, James M.

    1988-01-01

    Heliothermal lakes are density-stratified with shallow submerged margins surrounding areally restricted deep pool(s) containing a dense brine overlain by a much less dense brine. The reflective brine interface allows solar energy to be trapped in the dense brine which may warm to over 90 degree C. Carbonate precipitated from the dense brine is the typical sediment produced in warm deep pool. Miocene borate deposits of the Death Valley region are typically contained within areally limited carbonate-rich pods that interfinger with a finely interlaminated (varve-like) mudstone and limestone. Primary borates there are predominately either Na-Ca borates or Ca-borates. This bimodal evaporite assemblage suggests that brine chemistries and (or) crystallization paths varied significantly in temporally and spatially related portions of this apparently continuous lacustrine deposit.

  16. Great Lakes Region Morphology and Impacts of March 17, 2015 SED Geomagnetic Storm

    NASA Astrophysics Data System (ADS)

    Heine, T.; Moldwin, M.; Zou, S.

    2015-12-01

    Under quiet geomagnetic conditions, the mid-latitude ionosphere is relatively uniform with little spatial variation in electron density. However, during intense geomagnetic storms, density gradients associated with Storm Enhanced Density (SED) plumes and Sub-auroral Polarization Streams (SAPS) can move across the dayside mid-latitude ionosphere producing small spatial scale density structure that may be connected to ionospheric scintillation. The evolution of the SED plume during the March 17, 2015 "St. Patrick's Day Storm" is investigated using aggregated data from high resolution GPS receivers at the University of Michigan and throughout the Great Lakes region. Structural density features in the SED gradient can be observed and compared to GPS scintillation measurements—providing insight into the physical mechanisms behind ionospheric scintillation.

  17. Malachite green and chloramphenicol in aquatic products from regions around Dongting Lake in Hunan, China.

    PubMed

    He, Jiang; Cui, Jingzhen

    2016-01-01

    Aquatic products are important sources of animal proteins in human diet, especially in developing countries. As such, the safety of aquatic products is of primary concern. In this study, a standard method is used to detect malachite green (MG) and chloramphenicol (CAP) and to analyse the contents of these banned chemicals in turtle, mandarin fish and grass carp sampled from the region surrounding Dongting Lake area in Hunan, China. Results showed that 10.6% of the samples were MG-positive, most of them turtles. CAP was found in 8.3% of the samples, mostly in mandarin fish. These data indicated that these banned substances are still used in the surveyed area. Hence, adequate strategies must be implemented by the local government to control these banned substances. PMID:26496159

  18. Hindcasting water clarity from Landsat satellite images of unmonitored shallow lakes in the Waikato region, New Zealand.

    PubMed

    Hicks, Brendan J; Stichbury, Glen A; Brabyn, Lars K; Allan, Mathew G; Ashraf, Salman

    2013-09-01

    Cost-effective monitoring is necessary for all investigations of lake ecosystem responses to perturbations and long-term change. Satellite imagery offers the opportunity to extend low-cost monitoring and to examine spatial and temporal variability in water clarity data. We have developed automated procedures using Landsat imagery to estimate total suspended sediments (TSS), turbidity (TURB) in nephlometric turbidity units (NTU) and Secchi disc transparency (SDT) in 34 shallow lakes in the Waikato region, New Zealand, over a 10-year time span. Fifty-three Landsat 7 Enhanced Thematic Mapper Plus images captured between January 2000 and March 2009 were used for the analysis, six of which were captured within 24 h of physical in situ measurements for each of 10 shallow lakes. This gave 32-36 usable data points for the regressions between surface reflectance signatures and in situ measurements, which yielded r (2) values ranging from 0.67 to 0.94 for the three water clarity variables. Using these regressions, a series of Arc Macro Language scripts were developed to automate image preparation and water clarity analysis. Minimum and maximum in situ measurements corresponding to the six images were 2 and 344 mg/L for TSS, 75 and 275 NTU for TURB, and 0.05 and 3.04 m for SDT. Remotely sensed water clarity estimates showed good agreement with temporal patterns and trends in monitored lakes and we have extended water clarity datasets to previously unmonitored lakes. High spatial variability of TSS and water clarity within some lakes was apparent, highlighting the importance of localised inputs and processes affecting lake clarity. Moreover, remote sensing can give a whole lake view of water quality, which is very difficult to achieve by in situ point measurements. PMID:23430067

  19. High-resolution regional paleoclimate simulations of Lake Bonneville and its influence on geomorphic processes in the Uinta Mountains during the Last Glacial Maximum (Invited)

    NASA Astrophysics Data System (ADS)

    Galewsky, J.

    2013-12-01

    Reconstructed equilibrium line altitudes (ELAs) for alpine glaciers in the Uinta Mountains at the Last Glacial Maximum (LGM) increase with distance from the shoreline of pluvial Lake Bonneville, an effect that has been linked at least in part to enhanced precipitation derived from Lake Bonneville. While this result is broadly consistent with relatively large-scale climate modeling studies, the precise meteorological mechanisms by which Lake Bonneville may have influenced the glacial geomorphology of the Uinta Mountains remain poorly understood. New, high resolution (4km grid spacing) quasi-idealized regional paeoclimate simulations of the LGM computed with the Weather Research and Forecast (WRF) model provide new insights into these processes. Preliminary results indicate that moisture derived from Lake Bonneville likely would not have exerted a significant impact on regional precipitation unless the lake temperature exceeded about 4 degrees C. However, an ice-free Lake Bonneville would have likely exerted a modest (at least 1-2C) local warming, with associated impacts on precipitation and snowpack development. While the overall snowfall amounts do not appear to be greatly affected by the presence of a cold, ice-free lake, the presence of such a lake does appear to influence precipitation extremes throughout the region. These results suggest that the local temperature influence of pluvial lakes on regional glaciation may be of similar magnitude to the effects of enhanced evaporation from those lakes.

  20. Upper-mantle velocity structure of the lower Great Lakes region

    NASA Astrophysics Data System (ADS)

    Aktas, Kadircan; Eaton, David W.

    2006-06-01

    The lithospheric root beneath North America contains a prominent indentation beneath the lower Great Lakes region that is approximately aligned with the track of the New England seamounts. By combining data from the recently installed POLARIS network in southern Ontario, Canada with data acquired in 1996 during the Abitibi-Grenville teleseismic experiment, we have performed a tomographic inversion using 4543 P-wave traveltimes from 213 events (5.0 ≤ mb ≤ 6.6), and 1860 S-wave traveltimes from 98 events (5.0 ≤ mb ≤ 6.6), to obtain high-resolution images of the upper mantle beneath the lower Great Lakes. Two salient features of the 3-D models are: 1) a patchy, NNW-trending low-velocity region, and 2) a linear, NE-striking high-velocity anomaly. S-wave images show that the low-velocity anomaly changes from an arcuate feature at 400-km depth, to a NW-striking linear feature at 100-km depth beneath the Neoproterozoic Ottawa-Bonnechere graben. The linear high-velocity anomaly extends to at least 300-km depth and strikes parallel to surface geological belts and the Laurentian continental margin. We interpret the high-velocity anomaly as a possible relict slab associated with ca. 1.35-1.3 Ga subduction beneath the Composite Arc Belt, whereas the low-velocity anomaly is interpreted as a zone of alteration and metasomatism associated with the ascent of magmas that produced the Late Cretaceous Monteregian plutons. Our data support an interpretation of these plutons as melts generated by the passage of North America across a mantle plume, rather than a far-field response to opening of the North Atlantic.

  1. Landscape attributes driving avian influenza virus circulation in the Lake Alaotra region of Madagascar.

    PubMed

    Guerrini, Laure; Paul, Mathilde C; Leger, Lucas; Andriamanivo, Harentsoaniaina R; Maminiaina, Olivier F; Jourdan, Marion; Molia, Sophie; Rakotondravao, René; Chevalier, Véronique

    2014-05-01

    While the spatial pattern of the highly pathogenic avian influenza H5N1 virus has been studied throughout Southeast Asia, little is known on the spatial risk factors for avian influenza in Africa. In the present paper, we combined serological data from poultry and remotely sensed environmental factors in the Lake Alaotra region of Madagascar to explore for any association between avian influenza and landscape variables. Serological data from cross-sectional surveys carried out on poultry in 2008 and 2009 were examined together with a Landsat 7 satellite image analysed using supervised classification. The dominant landscape features in a 1-km buffer around farmhouses and distance to the closest water body were extracted. A total of 1,038 individual bird blood samples emanating from 241 flocks were analysed, and the association between avian influenza seroprevalence and these landcape variables was quantified using logistic regression models. No evidence of the presence of H5 or H7 avian influenza subtypes was found, suggesting that only low pathogenic avian influenza (LPAI) circulated. Three predominant land cover classes were identified around the poultry farms: grassland savannah, rice paddy fields and wetlands. A significant negative relationship was found between LPAI seroprevalence and distance to the closest body of water. We also found that LPAI seroprevalence was higher in farms characterised by predominant wetlands or rice landscapes than in those surrounded by dry savannah. Results from this study suggest that if highly pathogenic avian influenza H5N1 virus were introduced in Madagascar, the environmental conditions that prevail in Lake Alaotra region may allow the virus to spread and persist. PMID:24893021

  2. Subsurface structural mapping of Northern Nasser Lake region, Aswan, Egypt, using Bouguer data

    NASA Astrophysics Data System (ADS)

    Saleh, Salah

    2011-01-01

    In this study, we attempt to delineate the subsurface structures for the tectonic active region of Northern Nasser Lake using integrated interpretation techniques of gravity data with seismicity. The depths to the gravity sources, and the locations of the contacts of density contrast were estimated. Two methods were used for estimating source depths and contact locations: horizontal gradient (HG) and Euler deconvolution methods. Moreover, power spectral analysis, bandpass and upward continuation techniques were applied to evaluate the shallow and deep seated structures. Shallow depth structures were ranging between 0.30 km and 0.80 km. However, two average levels (interfaces) at depth 3.1 km and 7.2 km below the measuring level were revealed for the intermediate and deep seated structures respectively. Results of Euler deconvolution method suggested that, in the eastern part of the area, the basement could be observed on the ground and has become deeper in the central part. The interpreted structural map reveals that the area is affected by a set of faults trending mainly in the NW, E-W, N-S and NE-SW directions. Actually, this map has confirmed the idea that the intersections between the N-S and E-W striking faults along Nasser Lake area have generated seismic pulses. Moreover, three seismic zones (Z1, Z2 and Z3) are well correlated with the fault trends of the subsurface structures as derived from the horizontal gradient map. The present results suggest that there exist seismically-active fault east of High Dam, passing throughout Aswan reservoir from north to south. This fault is occupying region of high stress values which may generate large earthquakes in future, as it has long extension over several kilometers. Furthermore, the evaluated intruded volcanic bodies are found almost at the intersections between the E-W and NW oriented faults. Finally, the area is dissected by basement uplifts and troughs controlled mainly by the NW-SE faults.

  3. The farmers' perceptions of ANPS pollution and its influencing factors in Poyang Lake Region, China.

    PubMed

    Chen, Meiqiu; Chen, Mengjiao; Lu, Yanfei; Wang, Liguo; Huang, Yujiao

    2016-01-01

    Individual farmers represent the main management entities of agricultural production under the family-contract responsibility system in China, and thus play crucial roles in the prevention and control of agricultural nonpoint source (ANPS) pollution. The analysis of the farmers' perceptions of ANPS pollution as well as the factors affecting their perceptions can provide valuable information for relevant policy-making to preserve high quality water in Poyang Lake and regional quality of arable land. Through a survey titled 'Farmers' perceptions of ANPS pollution and farming behaviors in the Poyang Lake Region', the data related to the perceptions of farmers on ANPS pollution were collected. The factors that affect their awareness of ANPS pollution were identified with the method of boosted regression trees (BRT). The results indicated that the farmers had awareness of the risk of ANPS pollution to some extent, but they lacked adequate scientific knowledge. Generally, they had no consciousness about how to prevent and control ANPS pollution and did not understand techniques needed for proper scientifically sound application of fertilizers and pesticides. The main factors that influenced their perceptions of ANPS pollution are (from high to low): the ratio of total income which comes from farming, per capita farmland, age, education level, and household income. Some measures targeted to improve the prevention and control of ANPS pollution were proposed: developing modern agricultural techniques and promoting large-scale farming, increasing public campaigns related to ANPS pollution prevention and control with the goal of raising the level of awareness of farmers, and reforming the methods used to promote science and technology in agriculture and encourage the proper use of chemical fertilizers and pesticides. PMID:27054730

  4. An integrated approach for estimation of methane emissions from wetlands and lakes in high latitude regions

    NASA Astrophysics Data System (ADS)

    Chiu, C.; Bowling, L. C.; Podest, E.; Bohn, T. J.; Lettenmaier, D. P.; Schroeder, R.; McDonald, K. C.

    2009-04-01

    In recent years, there has been increasing evidence of significant alteration in the extent of lakes and wetlands in high latitude regions due in part to thawing permafrost, as well as other changes governing surface and subsurface hydrology. Methane is a 23 times more efficient greenhouse gas than carbon dioxide; changes in surface water extent, and the associated subsurface anaerobic conditions, are important controls on methane emissions in high latitude regions. Methane emissions from wetlands vary substantially in both time and space, and are influenced by plant growth, soil organic matter decomposition, methanogenesis, and methane oxidation controlled by soil temperature, water table level and net primary productivity (NPP). The understanding of spatial and temporal heterogeneity of surface saturation, thermal regime and carbon substrate in northern Eurasian wetlands from point measurements are limited. In order to better estimate the magnitude and variability of methane emissions from northern lakes and wetlands, we present an integrated assessment approach based on remote sensing image classification, land surface modeling and process-based ecosystem modeling. Wetlands classifications based on L-band JERS-1 SAR (100m) and ALOS PALSAR (~30m) are used together with topographic information to parameterize a lake and wetland algorithm in the Variable Infiltration Capacity (VIC) land surface model at 25 km resolution. The enhanced VIC algorithm allows subsurface moisture exchange between surface water and wetlands and includes a sub-grid parameterization of water table position within the wetland area using a generalized topographic index. Average methane emissions are simulated by using the Walter and Heimann methane emission model based on temporally and spatially varying soil temperature, net primary productivity and water table generated from the modified VIC model. Our five preliminary study areas include the Z. Dvina, Upper Volga, Yeloguy, Syum, and Chaya

  5. Epidemiological Features and Effectiveness of Schistosomiasis Control Programme in Lake and Marshland Region in The People's Republic of China.

    PubMed

    Zhang, S-Q; Sun, C-S; Wang, M; Lin, D-D; Zhou, X-N; Wang, T-P

    2016-01-01

    Schistosomiasis is one of neglected tropical diseases in the world. The People's Republic of China has made great achievements in schistosomiasis control through integrated interventions. Although the morbidity and mortality have been reduced to the lowest level in all three endemic regions, namely lake and marshland regions, hilly and mountainous regions and plains with waterway networks regions, the endemic status in lake and marshland region is still that of implementing the interventions in the higher endemicity areas towards elimination of schistosomiasis transmission. This review explores and analyses the endemic characteristics, control measures and its effectiveness in the course of schistosomiasis control programme, in order to provide more theoretical information and experiences for development of appropriate strategies leading to schistosomiasis elimination in the next stage in the country. PMID:27137442

  6. Implementation of local grid refinement (LGR) for the Lake Michigan Basin regional groundwater-flow model

    USGS Publications Warehouse

    Hoard, C.J.

    2010-01-01

    The U.S. Geological Survey is evaluating water availability and use within the Great Lakes Basin. This is a pilot effort to develop new techniques and methods to aid in the assessment of water availability. As part of the pilot program, a regional groundwater-flow model for the Lake Michigan Basin was developed using SEAWAT-2000. The regional model was used as a framework for assessing local-scale water availability through grid-refinement techniques. Two grid-refinement techniques, telescopic mesh refinement and local grid refinement, were used to illustrate the capability of the regional model to evaluate local-scale problems. An intermediate model was developed in central Michigan spanning an area of 454 square miles (mi2) using telescopic mesh refinement. Within the intermediate model, a smaller local model covering an area of 21.7 mi2 was developed and simulated using local grid refinement. Recharge was distributed in space and time using a daily output from a modified Thornthwaite-Mather soil-water-balance method. The soil-water-balance method derived recharge estimates from temperature and precipitation data output from an atmosphere-ocean coupled general-circulation model. The particular atmosphere-ocean coupled general-circulation model used, simulated climate change caused by high global greenhouse-gas emissions to the atmosphere. The surface-water network simulated in the regional model was refined and simulated using a streamflow-routing package for MODFLOW. The refined models were used to demonstrate streamflow depletion and potential climate change using five scenarios. The streamflow-depletion scenarios include (1) natural conditions (no pumping), (2) a pumping well near a stream; the well is screened in surficial glacial deposits, (3) a pumping well near a stream; the well is screened in deeper glacial deposits, and (4) a pumping well near a stream; the well is open to a deep bedrock aquifer. Results indicated that a range of 59 to 50 percent of the

  7. Modeling Regional Groundwater Implications of Biofuel Crop Production in the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Parish, A.; Kendall, A. D.; Basso, B.; Hyndman, D. W.

    2013-12-01

    In response to a growing call for renewable sources of energy that do not compete directly with food resources, the use of second-generation 'cellulosic' biofuel feedstocks has gained much attention in recent years. The push to advance the technologies that would make such a transformation possible is motivated by the United States Renewable Fuel Standard mandate to produce 36 billion gallons of biofuels by 2022, an increase of 334 percent from 2009. Many different crops, including maize, miscanthus, switchgrass, and poplar have shown promise as cellulosic feedstocks, and in an attempt to supply the needed biomass to meet the 2022 mandate, production of these crops have been on the rise. Yet little is known about the sustainability of large-scale conversion of land to cellulosic biofuel crop production; more research is needed to understand the effects that these crops will have on the quality and quantity of groundwater. This study presents a model scale-up approach to address three questions: What are the hydrologic and nutrient demands of the primary biofuel crops? Which biofuel crops are more water efficient in terms of demand verses energy produced? What are the types and availabilities of land to expand production of these biofuel crops? To answer these questions, we apply a point-based crop dynamics model in combination with a regional-scale hydrologic model, parameterized using stream discharge and chemistry data collected from two representative watersheds in Wisconsin. Approximately 17 stream sites in each watershed are selected for data collection for model parameterization, including stream discharge, nutrient concentrations, and basic chemical characteristics. We then use the System Approach to Land Use Sustainability (SALUS) model, which predicts crop growth under varying soil and climate conditions, to drive vegetation dynamics and groundwater transport of nutrients within the Integrated Landscape Hydrology Model (ILHM). ILHM predictions of stream

  8. INDICATORS OF ECOLOGICAL STRESS AND THEIR EXTENT IN THE POPULATION OF NORTHEASTERN LAKES: A REGIONAL-SCALE ASSESSMENT

    EPA Science Inventory

    One of the Environmental Monitoring and Assessment Program's first projects was a survey of 345 lakes in the eight states of the Northeast, during summers of 1991-1996. This survey was the first regional-scale attempt to use a probability-based sampling design to collect biolog...

  9. Evaluation of Sugar Maple Dieback in the Upper Great Lakes Region and Development of a Forest Health Youth Education Program

    ERIC Educational Resources Information Center

    Bal, Tara L.

    2013-01-01

    Sugar Maple, "Acer saccharum" Marsh., is one of the most valuable trees in the northern hardwood forests. Severe dieback was recently reported by area foresters in the western Upper Great Lakes Region. Sugar Maple has had a history of dieback over the last 100 years throughout its range and different variables have been identified as…

  10. An Overview of Interdisciplinary Research at Notre Dame Addressing "Grand Challenges" in the Midwest and Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Hamlet, A. F.; Bolster, D.; Tank, J. L.; Hellmann, J.; Christopher, S. F.; Sharma, A.; Chiu, C. M.

    2014-12-01

    The Midwest and Great Lakes region face a number of "Grand Challenges" associated with climate, land use, agriculture, and water resources infrastructure. These include sustainability of agricultural systems and related impacts to food security and the regional economy; sustainability of Great Lakes water levels; changing storm statistics and impacts to stormwater management and flooding; water quality in rivers and downstream receiving water bodies related to non-point source pollution on agricultural lands and combined sewer overflows in urban areas; urban impacts related to aging infrastructure and climate change, and ecosystem management and restoration. In the context of water management, groundwater resources are poorly understood in comparison with surface water resources, and regional-scale simulation models are needed to address questions of sustainability both in terms of supply and water quality. Interdisciplinary research at the University of Notre Dame is attempting to address these research challenges via 1) integrated macro-scale groundwater and surface water modeling to address issues related to sustainable water supply, ecosystem restoration, and agricultural impacts; 2) development of high-resolution regional climate models dynamically coupled to the Great Lakes to address urban impacts, changing storm statistics and to quantify precipitation and evaporation over the Great Lakes; 3) and integrated macro-scale hydrology and water quality modeling to assess the large-scale performance of innovative land management BMPs on agricultural land (such as the two-stage ditch, cover crops, and dynamic drainage control) intended to improve water quality.

  11. REGIONAL, WATERSHED, AND SITE-SPECIFIC ENVIRONMENTAL INFLUENCES ON FISH ASSEMBLAGE STRUCTURE AND FUNCTION IN WESTERN LAKE SUPERIOR TRIBUTARIES

    EPA Science Inventory

    The relative importance of regional, watershed, and in-stream environmental factors on stream fish assemblage structure and function was investigated as part of a comparative watershed project in the western Lake Superior basin. We selected 48 second and third order watersheds fr...

  12. A Network for Educational Change in the Great Lakes Region: A View through the Lens of Educational Service Agencies

    ERIC Educational Resources Information Center

    Peters, Randal E.; Svedkauskaite, Asta

    2008-01-01

    The major purpose of this descriptive report is to provide an overview of the structure, capacity, and roles of educational service agencies (ESAs) across five states--Illinois, Indiana, Michigan, Ohio, and Wisconsin--in the Great Lakes region, within the context of the broader statewide systems of support for educational improvement and progress.…

  13. Mapping landslide processes in the North Tanganyika - Lake Kivu rift zones: towards a regional hazard assessment

    NASA Astrophysics Data System (ADS)

    Dewitte, Olivier; Monsieurs, Elise; Jacobs, Liesbet; Basimike, Joseph; Delvaux, Damien; Draida, Salah; Hamenyimana, Jean-Baptiste; Havenith, Hans-Balder; Kubwimana, Désiré; Maki Mateso, Jean-Claude; Michellier, Caroline; Nahimana, Louis; Ndayisenga, Aloys; Ngenzebuhoro, Pierre-Claver; Nkurunziza, Pascal; Nshokano, Jean-Robert; Sindayihebura, Bernard; Philippe, Trefois; Turimumahoro, Denis; Kervyn, François

    2015-04-01

    The mountainous environments of the North Tanganyika - Lake Kivu rift zones are part of the West branch of the East African Rift. In this area, natural triggering and environmental factors such as heavy rainfalls, earthquake occurrences and steep topographies favour the concentration of mass movement processes. In addition anthropogenic factors such as rapid land use changes and urban expansion increase the sensibility to slope instability. Until very recently few landslide data was available for the area. Now, through the initiation of several research projects and the setting-up of a methodology for data collection adapted to this data-poor environment, it becomes possible to draw a first regional picture of the landslide hazard. Landslides include a wide range of ground movements such as rock falls, deep failure of slopes and shallow debris flows. Landslides are possibly the most important geohazard in the region in terms of recurring impact on the populations, causing fatalities every year. Many landslides are observed each year in the whole region, and their occurrence is clearly linked to complex topographic, lithological and vegetation signatures coupled with heavy rainfall events, which is the main triggering factor. Here we present the current knowledge of the various slope processes present in these equatorial environments. A particular attention is given to urban areas such as Bukavu and Bujumbura where landslide threat is particularly acute. Results and research perspectives on landslide inventorying, monitoring, and susceptibility and hazard assessment are presented.

  14. Scenario-based water resources planning for utilities in the Lake Victoria region

    NASA Astrophysics Data System (ADS)

    Mehta, V. K.; Aslam, O.; Dale, L.; Miller, N.; Purkey, D.

    2010-12-01

    Cities in the Lake Victoria (LV) region are experiencing the highest growth rates in Africa, at the same time that their water resource is threatened by domestic waste and industrial pollution. Urban centers use local springs, wetlands and Lake Victoria as source waters. As efforts to meet increasing demand accelerate, integrated water resources management (IWRM) tools provide opportunities for utilities and other stakeholders to develop a planning framework comprehensive enough to include short term (e.g. landuse change), as well as longer term (e.g. climate change) scenarios. This paper presents IWRM models built using the Water Evaluation And Planning (WEAP) decision support system, for three pilot towns in the LV region - Bukoba (Tanzania), Masaka (Uganda), and Kisii (Kenya). Their current populations are 100,000, 70,000 and 200,000 respectively. Demand coverage is ~70% in Masaka and Bukoba, and less than 50% in Kisii. IWRM models for each town were calibrated under current system performance based on site visits, utility reporting and interviews. Projected water supply, demand, revenues and costs were then evaluated against a combination of climate, demographic and infrastructure scenarios upto 2050. In Masaka, flow and climate data were available to calibrate a runoff model to simulate streamflow at water intake. In Masaka, without considering climate change, the system is infrastructure-limited and not water availability (hydrology) limited until 2035, under projected population growth of 2.17%. Under a wet climate scenario as projected by GCM’s for the LV region, the current wetland source could supply all expected demands until 2050. Even under a drought scenario, the wetland could supply all demand until 2032, if the supply infrastructure is updated at an estimated cost of USD 10.8 million. However, demand targets can only be met at the expense of almost no water returning to the wetland downstream of the intake by 2035, unless substantial investments

  15. Late-Holocene climate variability in southern New Zealand: A multi-proxy study of lake sediments from Lake Ohau to reconstruct regional climate

    NASA Astrophysics Data System (ADS)

    Roop, H. A.; Vandergoes, M. J.; Levy, R. H.; Dunbar, G.; Upton, P.; Stumpner, P.; Fitzsimons, S.; Howarth, J. D.; Ditchburn, R.; Wilson, G. S.; Purdie, J.

    2012-12-01

    Driving this research is the need to improve understanding of synoptic climate systems influencing climate in southern New Zealand and to document changes in the character of these systems beyond the historical record. Inter-annual variability of New Zealand's climate (e.g. temperature and precipitation) is influenced by large-scale patterns originating in both the tropics (El-Niño-Southern Oscillation, Interdecadal Pacific Oscillation) and the Antarctic (Southern Annular Mode). Currently, very few highly resolved climate reconstructions exist in mid-latitudes of the Southern Hemisphere. The identification of annually laminated sediments in Lake Ohau, Mackenzie Basin, New Zealand (44.234°S, 169.854°E) offers a unique opportunity to investigate changes in regional hydrology and climate, and by extension also explore connections to large-scale climate patterns. Importantly, Lake Ohau is situated east of and in the lee of the Southern Alps, rendering the region characteristically dry and sensitive to small fluctuations in precipitation and temperature. Short cores (<6 meters) from Lake Ohau contain layered sedimentary couplets, which 137Cs and 210Pb analyses suggest represent annual accumulation of terrigenous sediment at an average rate of 0.5 cm a-1. Core imaging (RGB, L*), density, and magnetic susceptibility data were acquired using a GeoTek multi-sensor core logger. Here we present an initial assessment of couplet characteristics based on thin-sections, grain size analysis, and GeoTek output. Extensive limnological monitoring, including acoustic Doppler profilers, thermister strings, sediment traps, and turbidity meters will help to further develop a detailed understanding of processes driving seasonal sediment deposition in Lake Ohau. These limnological data, and preliminary correlations with lake inflow data (1924-2012), and local precipitation and temperature data (1910-2012) will also be presented. This work provides the foundation for reconstructing the

  16. New exposure ages for the Last Glacial Cycle in the Sanabria Lake region (northwestern Spain)

    NASA Astrophysics Data System (ADS)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; Domínguez-Cuesta, María Jose; Rinterknecht, Vincent; Pallàs, Raimon; Braucher, Régis; Bourlès, Didier; Valero-Garcés, Blas

    2013-04-01

    The Sanabria Lake region is located in the Trevinca Massif, a mid-latitude mountain area up to 2128 m asl in the northwest corner of the Iberian Peninsula (42oN 6oW). An ice cap glaciation took place during the Last Glacial Cycle in this massif, with an equilibrium line altitude of 1687 m for the Tera glacial outlet at its local maximum (Cowton et al., 2009). A well preserved glacial sequence occurs on an area of 45 km2 around the present Sanabria Lake (1000 m asl) and is composed by lateral and end moraines in close relationship with glaciolacustrine deposits. This sequence shows the ice snout oscillations of the former Tera glacier during the Last Glacial Cycle and offers a good opportunity to compare radiocarbon and OSL- based chronological models with new cosmogenic isotope dates. The new dataset of 10Be exposure ages presented here for the Sanabria Lake moraines is based on measurements conducted on 23 boulders and is compared with previous radiocarbon and OSL data conducted on ice related deposits (Pérez-Alberti et al., 2011; Rodríguez-Rodríguez et al., 2011). Our results are coherent with the available deglaciation radiocarbon chronology, and support a last deglaciation origin for the whole set of end moraines that are downstream the Sanabria Lake (19.2 - 15.7 10Be ka). Discrepancies between results of the different dating methods concern the timing of the local glacial maximum, with the cosmogenic exposure method always yielding the youngest minimum ages. As proposed to explain similar observations made elsewhere (Palacios et al., 2012), reconciling the ages from different dating methods would imply the occurrence of two glacial advances close enough in extent to generate an overlapping polygenic moraine. Cowton, T., Hughes, P.D., Gibbard, P.L., 2009. Palaeoglaciation of Parque Natural Lago de Sanabria, northwest Spain. Geomorphology 108, 282-291. Rodríguez-Rodríguez, L., Jiménez-Sánchez, M., Domínguez-Cuesta, M.J., Rico, M.T., Valero-Garcés, B

  17. Hazards Associated with High Altitude Rain-Fed Lakes (HARL) in the Overdeepened Deglaciated Region of Hindu Kush and Himalaya

    NASA Astrophysics Data System (ADS)

    Haritashya, U. K.; Hess, T. G.

    2014-12-01

    Mountain regions are changing rapidly as a result of climate change. It has been well established that these mountain regions are experiencing rapid glacier retreat. With accelerated retreat, glacial melt runoff can accumulate in an overdeepened glacier bed left behind by the receding glacier and can be bound by the walls of unstable frontal and lateral moraines to form a hazardous lake. However, when smaller glaciers retreat and downwaste they no longer contain enough ice to sustain the flow of water and maintain level of the lake. Furthermore, some smaller glaciers in the Hindu Kush and Himalayan region are observing extreme downwasting, which are either turning them into a rock glacier or heavily debris covered glacier leading to the reduced ice melt. Consequently, it is important to study these overdeepened beds, which are contained by the unstable mass. This is especially significant considering the great degree of complexity in the mountain weather system and recent examples of high intensity and short duration rainfall in the Hindu Kush region of Afghanistan, Karakoram region of Pakistan, and Central Himalayan region of India and Nepal. A precise understanding of mountain climate system is necessary, but so does these potentially deglaciated overdeepened beds where rain-fed lakes can form and increase systems hydrostatic pressure that can breach moraine containment and flood entire downstream region. Once lake has formed it possesses hydrological characteristics that are similar to the glacial lakes, which are known to put lives and infrastructure in danger. Therefore, in this study we evaluated overdeepened beds that are located in the complex topography and contained by abandoned or unstable lateral moraine using field and remote sensing satellite images. Our results provide degree of failure associated with these lakes based on the complex spatial and topological analysis as well as orographic distribution of the region. Such studies are not common in the

  18. Changes in winter air temperatures near Lake Michigan, 1851-1993, as determined from regional lake-ice records

    USGS Publications Warehouse

    Assel, R.A.; Robertson, Dale M.

    1995-01-01

    Records of freezeup and breakup dates for Grand Traverse Bay, Michigan, and Lake Mendota, Wisconsin, are among the longest ice records available near the Great Lakes, beginning in 185 1 and 1855, respectively. The timing of freezeup and breakup results from an integration of meteorological conditions (primarily air temperature) that occur before these events. Changes in the average timing of these ice-events are translated into changes in air temperature by the use of empirical and process-driven models. The timing of freezeup and breakup at the two locations represents an integration of air temperatures over slightly different seasons (months). Records from both locations indicate that the early winter period before about 1890 was - 15°C cooler than the early winter period after that time; the mean temperature has, however, remained relatively constant since about 1890. Changes in breakup dates demonstrate a similar 1.0-1 .5”C increase in late winter and early spring air temperatures about 1890. More recent average breakup dates at both locations have been earlier than during 1890-1940, indicating an additional warming of 1.2”C in March since about 1940 and a warming of 1 . 1°C in January-March since about 1980. Ice records at these sites will continue to provide an early indication of the anticipated climatic warming, not only because of the large response of ice cover to small changes in air temperature but also because these records integrate climatic conditions during the seasons (winter-spring) when most warming is forecast to occur. Future reductions in ice cover may strongly affect the winter ecology of the Great Lakes by reducing the stable environment required by various levels of the food chain. 

  19. Development of a total maximum daily load (TMDL) for acid-impaired lakes in the Adirondack region of New York

    NASA Astrophysics Data System (ADS)

    Fakhraei, Habibollah; Driscoll, Charles T.; Selvendiran, Pranesh; DePinto, Joseph V.; Bloomfield, Jay; Quinn, Scott; Rowell, H. Chandler

    2014-10-01

    Acidic deposition has impaired acid-sensitive surface waters in the Adirondack region of New York by decreasing pH and acid neutralizing capacity (ANC). In spite of air quality programs over past decades, 128 lakes in the Adirondacks were classified as “impaired” under Section 303(d) of the Clean Water Act in 2010 due to elevated acidity. The biogeochemical model, PnET-BGC, was used to relate decreases in atmospheric sulfur (S) and nitrogen (N) deposition to changes in lake water chemistry. The model was calibrated and confirmed using observed soil and lake water chemistry data and then was applied to calculate the maximum atmospheric deposition that the impaired lakes can receive while still achieving ANC targets. Two targets of ANC were used to characterize the recovery of acid-impaired lakes: 11 and 20 μeq L-1. Of the 128 acid-impaired lakes, 97 currently have ANC values below the target value of 20 μeq L-1 and 83 are below 11 μeq L-1. This study indicates that a moderate control scenario (i.e., 60% decrease from the current atmospheric S load) is projected to recover the ANC of lakes at a mean rate of 0.18 and 0.05 μeq L-1 yr-1 during the periods 2022-2050 and 2050-2200, respectively. The total maximum daily load (TMDL) of acidity corresponding to this moderate control scenario was estimated to be 7.9 meq S m-2 yr-1 which includes a 10% margin of safety.

  20. Local and Regional Determinants of an Uncommon Functional Group in Freshwater Lakes and Ponds

    PubMed Central

    McCann, Michael James

    2015-01-01

    A combination of local and regional factors and stochastic forces is expected to determine the occurrence of species and the structure of communities. However, in most cases, our understanding is incomplete, with large amounts of unexplained variation. Using functional groups rather than individual species may help explain the relationship between community composition and conditions. In this study, I used survey data from freshwater lakes and ponds to understand factors that determine the presence of the floating plant functional group in the northeast United States. Of the 176 water bodies surveyed, 104 (59.1%) did not contain any floating plant species. The occurrence of this functional group was largely determined by local abiotic conditions, which were spatially autocorrelated across the region. A model predicting the presence of the floating plant functional group performed similarly to the best species-specific models. Using a permutation test, I also found that the observed prevalence of floating plants is no different than expected by random assembly from a species pool of its size. These results suggest that the size of the species pool interacts with local conditions in determining the presence of a functional group. Nevertheless, a large amount of unexplained variation remains, attributable to either stochastic species occurrence or incomplete predictive models. The simple permutation approach in this study can be extended to test alternative models of community assembly. PMID:26121636

  1. On-line Education Initiatives to Galvanize Climate Mitigation in the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Mooney, M. E.; Ackerman, S. A.

    2014-12-01

    The Cooperative Institute for Meteorological Satellite Studies (CIMSS) is supporting two different on-line education initiatives that teach about climate change while emphasizing informed and effective responses. The first is an on-line introductory level course for undergraduate students (http://c3.ssec.wisc.edu/) offered through the University of Wisconsin-Madison Atmospheric and Oceanic Sciences (AOS) department. Along with a lighter carbon footprint and the convenience of web-based access, students interact via Drupal forums, Google hangouts and twitter. Activities include several pedagogical tools with sustainability-related content and a final project requiring a discussion of regionally relevant mitigation responses to achieve low emission scenarios for assigned locations. The other initiative is a MOOC (massive open online course) focusing on the changing weather and climate in the Great Lakes Region. This 4-week course is set to launch February 23 2015. One of the primary goals of this MOOC will be having participants change four habits, one per week. Each behavior change will provide a personal benefit to participating individuals while also helping to mitigate the collective impacts of climate change. This presentation will share strategies and insights from both projects.

  2. Spatial Analysis of Great Lakes Regional Icing Cloud Liquid Water Content

    NASA Technical Reports Server (NTRS)

    Ryerson, Charles C.; Koenig, George G.; Melloh, Rae A.; Meese, Debra A.; Reehorst, Andrew L.; Miller, Dean R.

    2003-01-01

    Abstract Clustering of cloud microphysical conditions, such as liquid water content (LWC) and drop size, can affect the rate and shape of ice accretion and the airworthiness of aircraft. Clustering may also degrade the accuracy of cloud LWC measurements from radars and microwave radiometers being developed by the government for remotely mapping icing conditions ahead of aircraft in flight. This paper evaluates spatial clustering of LWC in icing clouds using measurements collected during NASA research flights in the Great Lakes region. We used graphical and analytical approaches to describe clustering. The analytical approach involves determining the average size of clusters and computing a clustering intensity parameter. We analyzed flight data composed of 1-s-frequency LWC measurements for 12 periods ranging from 17.4 minutes (73 km) to 45.3 minutes (190 km) in duration. Graphically some flight segments showed evidence of consistency with regard to clustering patterns. Cluster intensity varied from 0.06, indicating little clustering, to a high of 2.42. Cluster lengths ranged from 0.1 minutes (0.6 km) to 4.1 minutes (17.3 km). Additional analyses will allow us to determine if clustering climatologies can be developed to characterize cluster conditions by region, time period, or weather condition. Introduction

  3. Regional significance of an early Holocene moraine in Enchantment Lakes basin, North Cascade Range, Washington

    USGS Publications Warehouse

    Waitt, R.B., Jr.; Yount, J.C.; Davis, P.T.

    1982-01-01

    The upper Enchantment Lakes basin in the North Cascade Range of Washington displays two moraine belts, each recording an episode of glacier advance after the end of the last glaciation. The inner belt, the Brynhild, 0.1 to 0.5 km beyond existing glaciers, postdates Mount St. Helens Wn tephra (???450 yr old), which lies only beyond the moraines. The morainal surface is only slightly weathered, is almost barren of lichens, and is devoid of soil, evidence suggesting that the Brynhild moraines are no more than a century old. The outer moraine, the Brisingamen, 0.3 to 0.7 km beyond existing glaciers, is weathered and is covered with large lichens. On and behind the Brisingamen moraine the Mazama ash (6900 yr old) is present beneath the Mount St. Helens Yn and Wn tephras. Despite more than 7 millennia of weathering, the rock surface behind the Brisingamen moraine is measurably less weathered than the surface beyond, which was last glaciated during the Rat Creek advance about 13,000 yr ago. The age of the Brisingamen moraine therefore is probably early Holocene. The Brisingamen moraine evidently correlates with moraines near Glacier Peak, near Mount Rainier, in northeastern and central Oregon, in the southern Canadian Rockies, and in the northern U.S. Rocky Mountains. These regional effects suggest that a climatic episode of cooling or increased snowfall affected the entire region some time during the early Holocene. ?? 1982.

  4. Sympatric wolf and coyote populations of the western Great Lakes region are reproductively isolated.

    PubMed

    Wheeldon, Tyler J; Patterson, Brent R; White, Bradley N

    2010-10-01

    Interpretation of the genetic composition and taxonomic history of wolves in the western Great Lakes region (WGLR) of the United States has long been debated and has become more important to their conservation given the recent changes in their status under the Endangered Species Act. Currently, the two competing hypotheses on WGLR wolves are that they resulted from hybridization between (i) grey wolves (Canis lupus) and western coyotes (C. latrans) or (ii) between grey wolves and eastern wolves (C. lycaon). We performed a genetic analysis of sympatric wolves and coyotes from the region to assess the degree of reproductive isolation between them and to clarify the taxonomic status of WGLR wolves. Based on data from maternal, paternal and bi-parental genetic markers, we demonstrate a clear genetic distinction between sympatric wolves and coyotes and conclude that they are reproductively isolated and that wolf-coyote hybridization in the WGLR is uncommon. The data reject the hypothesis that wolves in the WGLR derive from hybridization between grey wolves and western coyotes, and we conclude that the extant WGLR wolf population is derived from hybridization between grey wolves and eastern wolves. Grey-eastern wolf hybrids (C. lupus × lycaon) comprise a substantial population that extends across Michigan, Wisconsin, Minnesota and western Ontario. These findings have important implications for the conservation and management of wolves in North America, specifically concerning the overestimation of grey wolf numbers in the United States and the need to address policies for hybrids. PMID:20854277

  5. Monitoring rice cropping systems using China environment satellite data in Poyang Lake region

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jiang, Luguang; Feng, Zhiming

    Threshold method was utilized to discriminate rice cropping systems based on the noticeable variation of Normalized Difference Vegetation Index (NDVI) during key growth stages in Poyang Lake Region, China. This area is dominated by double- and single rice cropping systems which tend to change due to the frequent ecosystem management policies. We used a new satellite data from the CCD camera sensor with 30 m spatial resolution onboard the China Environmental Satellite HJ-1A and B. The HJ -1A/B with a better temporal resolution of four days provides more data options for effective and timely agriculture monitoring. The result showed that there is evident difference of NDVI between single and late rice during mid October when they are in different growth stages. The areas of single and late rice in 2011 were 2988.6 km2 and 3105.9 km2, respectively. Paddy field distribution map and local paddy rice calendar are requisite to move the threshold method into other multiple rice cropping regions. The study suggests that the China Environmental Satellite HJ-1A/B have the potential to rice cropping system in the double to triple rice cropping systems area. With many advantages of HJ-1A/B, like, finer spatial and temporal resolution, bigger imaging swath, it may make rice cropping system monitoring more feasible and operational.

  6. Scenario-based water resources planning for utilities in the Lake Victoria region

    NASA Astrophysics Data System (ADS)

    Mehta, Vishal K.; Aslam, Omar; Dale, Larry; Miller, Norman; Purkey, David R.

    Urban areas in the Lake Victoria (LV) region are experiencing the highest growth rates in Africa. As efforts to meet increasing demand accelerate, integrated water resources management (IWRM) tools provide opportunities for utilities and other stakeholders to develop a planning framework comprehensive enough to include short term (e.g. landuse change), as well as longer term (e.g. climate change) scenarios. This paper presents IWRM models built using the Water Evaluation And Planning (WEAP) decision support system, for three towns in the LV region - Bukoba (Tanzania), Masaka (Uganda), and Kisii (Kenya). Each model was calibrated under current system performance based on site visits, utility reporting and interviews. Projected water supply, demand, revenues and costs were then evaluated against a combination of climate, demographic and infrastructure scenarios up to 2050. Our results show that water supply in all three towns is currently infrastructure limited; achieving existing design capacity could meet most projected demand until 2020s in Masaka beyond which new supply and conservation strategies would be needed. In Bukoba, reducing leakages would provide little performance improvement in the short-term, but doubling capacity would meet all demands until 2050. In Kisii, major infrastructure investment is urgently needed. In Masaka, streamflow simulations show that wetland sources could satisfy all demand until 2050, but at the cost of almost no water downstream of the intake. These models demonstrate the value of IWRM tools for developing water management plans that integrate hydroclimatology-driven supply to demand projections on a single platform.

  7. Housing Archetype Analysis for Home Energy-Efficient Retrofit in the Great Lakes Region

    SciTech Connect

    Kim, S. K.; Mrozowski, T.; Harrell-Seyburn, A.; Ehrlich, N.; Hembroff, L.; Bieburn, B.; Mazor, M.; McIntyre, A.; Mutton, C.; Parsons, G.; Syal, M. G.; Wilkinson, R.

    2014-09-01

    This project report details activities and results of the 'Market Characterization' project undertaken by the Cost Effective Energy Retrofit (CEER) team targeted toward the DOE goal of achieving 30%-50% reduction in existing building energy use. CEER consists of members from the Dow Chemical Company, Michigan State University, Ferris State University and Habitat for Humanity Kent County. The purpose of this market characterization project was to identify housing archetypes which are dominant within Great Lakes region and therefore offer significant potential for energy-efficient retrofit research and implementation due to the substantial number of homes possessing similar characteristics. Understanding the characteristics of housing groups referred to as 'archetypes' by vintage, style, and construction characteristics can allow research teams to focus their retrofit research and develop prescriptive solutions for those structure types which are prevalent and offer high potential uptake within a region or market. Key research activities included; literature review, statistical analysis of national and regional data of the American Housing Survey (AHS) collected by the U.S. Census Bureau, analysis of Michigan specific data, development of a housing taxonomy of architectural styles, case studies of two local markets (i.e., Ann Arbor and Grand Rapids in Michigan) and development of a suggested framework (or process) for characterizing local markets. In order to gain a high level perspective, national and regional data from the U.S. Census Bureau was analyzed using cross tabulations, multiple regression models, and logistic regression to characterize the housing stock and determine dominant house types using 21 variables.

  8. Distribution and dispersal of the zebra mussel (Dreissena polymorpha) in the Great Lakes region

    USGS Publications Warehouse

    Griffiths, Ronald W.; Schloesser, Donald W.; Leach, Joseph H.; Kovalak, William P.

    1991-01-01

    Dreissena polymorpha (Pallas), a small mussel common throughout most of Europe, was discovered in June of 1988 in the southern part of Lake St. Clair. Length–frequency analyses of populations from the Great Lakes and review of historical benthic studies suggest that the mussel was introduced into Lake St. Clair in late 1986, probably as a result of the discharge of ballast water from an ocean-crossing vessel. Following the 1990 reproductive season, Dreissenapopulations ranged from the head of the St. Clair River, through Lake St. Clair, the Detroit River, Lake Erie, the Welland Canal, and the Niagara River to the western basin and southern shoreline of Lake Ontario. Isolated populations were found in the St. Lawrence River and in harbours in Lakes Huron, Michigan, and Superior. The rapid dispersal of this organism has resulted from its high fecundity, pelagic larval stage, bysso-pelagic drifting ability of juveniles, and human activities associated with commercial shipping, fishing, and boating (research and pleasure). Virtually any waterbody that can be reached by boaters and fisherman within a few days travel of the lower Great Lakes, particularly Lake Erie, seems to be at risk of being invaded by this nuisance species.

  9. A review of factors affecting productivity of bald eagles in the Great Lakes region: implications for recovery.

    PubMed

    Bowerman, W W; Giesy, J P; Best, D A; Kramer, V J

    1995-05-01

    The bald eagle (Haliaeetus leucocephalus) population in North America declined greatly after World War II due primarily to the eggshell thinning effects of p,p'-DDE, a biodegradation product of DDT. After the banning of DDT in the United States and Canada during the early 1970s, the bald eagle population started to increase. However, this population recovery has not been uniform. Eagles nesting along the shorelines of the North American Great Lakes and rivers open to spawning runs of anadromous fishes from the Great Lakes still exhibit impaired reproduction. We have explored both ecological and toxicological factors that would limit reproduction of bald eagles in the Great Lakes region. Based on our studies, the most critical factors influencing eagle populations are concentrations of environmental toxicants. While there might be some continuing effects of DDE, total PCBs and most importantly 2,3,7,8-tetrachlordibenzo-p-dioxin equivalents (TCDD-EQ) in fishes from the Great Lakes and rivers open to spawning runs of anadromous fishes from the Great Lakes currently represent a significant hazard to bald eagles living along these shorelines or near these rivers and are most likely related to the impaired reproduction in bald eagles living there. PMID:7556024

  10. Estimation of nonpoint source loadings of phosphorus for lakes in the Puget Sound region, Washington

    USGS Publications Warehouse

    Gilliom, Robert J.

    1983-01-01

    Control of eutrophication of lakes in watersheds undergoing development is facilitated by estimates of the amounts of phosphorus (P) that reach the lakes from areas under various types of land use. Using a mass-balance model, the author calculated P loadings from present-day P concentrations measured in lake water and from other easily measured physical characteristics in a total of 28 lakes in drainage basins that contain only forest and residential land. The loadings from background sources (forest-land drainage and bulk precipitation) to each of the lakes were estimated by methods developed in a previous study. Differences between estimated present-day P loadings and loadings from background sources were attributed to changes in land use. The mean increase in annual P yield resulting from conversion of forest to residential land use was 7 kilograms per square kilometer, not including septic tank system contributions. Calculated loadings from septic systems were found to correlate best with the number of near-shore dwellings around each lake in 1940. The regression equation expressing this relationship explained 36 percent of the sample variance. There was no significant correlation between estimated septic tank system P loadings and number of dwellings present in 1960 or 1970. The evidence indicates that older systems might contribute more phosphorus to lakes than newer systems, and that there may be substantial time lags between septic system installation and significant impacts on lake-water P concentrations. For lakes in basins that contain agricultural land, the P loading attributable to agriculture can be calculated as the difference between the estimated total loading and the sum of estimated loadings from nonagricultural sources. A comprehensive system for evaluating errors in all loading estimates is presented. The empirical relationships developed allow preliminary approximations of the cumulative impact development has had on P loading and the amounts

  11. Estimation of background loadings and concentrations of phosphorus for lakes in the Puget Sound region, Washington

    USGS Publications Warehouse

    Gilliom, Robert J.

    1980-01-01

    For lakes in watersheds that include developed land, evaluation of eutrophication is facilitated by knowledge of changes in the lakes ' phosphorus concentration since development. A method is described for estimating background phosphorus concentration in lakes of the Puget Sound lowland, Washington. Using a mass-balance ' Vollenweider-type ' model, phosphorus loadings were calculated from present-day phosphorus concentrations measured in lake water and from easily measured physical characteristics for 24 lakes in undeveloped, or insignificantly developed, watersheds. Phosphorus loading from forest (undeveloped) land was derived for each lake as the difference between the calculated phosphorus loading directly to the lake 's surface and loading by bulk precipitation (estimated from other studies). Forest-land loading to each lake was converted to the yield (mass per unit area) of the forested part of the watershed. The phosphorus yield from forest land was related to annual runoff, and the regression equation expressing this relationship explained 73% of the sample variance. By applying that regression equation to the appropriate annual-runoff data, the yield of phosphorus from forest land can be estimated for any lake in the study area. Phosphorus loading from forested land then can be added to direct loading by bulk precipitation to estimate background phosphorus loading for each lake. By applying the mass-balance model to calculated background loadings, background total-phosphorus concentration can also be calculated for all lakes in the study area that have stable thermal stratification during the summer. The standard error of estimate for calculated background loadings and concentrations averages about 25%. (USGS)

  12. A Holocene molluscan succession from floodplain sediments of the upper Lena River (Lake Baikal region), Siberia

    NASA Astrophysics Data System (ADS)

    White, Dustin; Preece, Richard C.; Shchetnikov, Alexander A.; Parfitt, Simon A.; Dlussky, Konstantin G.

    2008-05-01

    Floodplain sediments of the upper Lena River near Basovo in south-central Siberia have yielded the most detailed Holocene molluscan succession yet reported from the entire eastern Palaearctic. Over 72,500 shells from at least 28 species of terrestrial and 23 species of freshwater mollusc have been recovered, an abundance and diversity far higher than previously reported from the region. The molluscan assemblages are dominated by land snails, especially members of the genus Vallonia, represented by five species including Vallonia tenuilabris and two poorly known species Vallonia kamtschatica and Vallonia cf. chinensis. Other noteworthy species recovered include Gastrocopta theeli, Carychium pessimum, Vertigo extima (southernmost record), Vertigo microsphaera and the first Asian records of three other taxa ( Vertigo geyeri, Vertigo genesii and Vertigo parcedentata). Illustrations are provided for the critical species, since opinions differ about the status of various taxa and the correct names that should be used. The molluscan assemblages show clear successional trends during the early to mid-Holocene, reflecting episodes of dryness/wetness on the floodplain. Drier conditions at ca 6350 14C yr BP coincide with major changes in the archaeological record seen at other sites in the region but it remains unclear whether the two are linked. A prominent charcoal-rich horizon dated to ca 2800 14C yr BP marks a burning event in the catchment, which resulted in a two-fold increase in sediment accumulation rate. Remains of small mammals occurred throughout the sequence including a tooth of Microtus cf. maximowiczii, possibly the first occurrence of Ungar vole west of Lake Baikal. The faunal analyses have been integrated with a detailed pedological study of the sedimentary profile and a chronology was obtained by means of 12 AMS radiocarbon dates. This study provides the first detailed palaeoecological information relating to Holocene molluscan assemblages from the Cis

  13. Glacial erosion of bedrock and preliminary Quaternary stratigraphy in the western Lake Erie coastal region

    SciTech Connect

    Shideler, G.I. ); Stone, B.D. )

    1994-04-01

    An analysis of 120 km of high-resolution seismic reflection profiles and onshore well records in the southwestern Lake Erie coastal zone shows a highly dissected bedrock surface. Regional subsurface data confirm extensive glacial modification of the preglacial landscape and the differential erosion of bedrock units. Areas of deep glacial scour coincide with shale and dolostone subcrop belts, in which bedrock strike direction was subparallel to glacial flow directions during early and late phases of glaciation. Locally, deep scouring also occurred over zones of fractured bedrock. In southeastern Michigan, large bedrock valleys, widened and deepened by glacial erosion, are preserved on the north side of the area of the Erie ice lobe. To the south in areas of axial flow of the Erie lobe and southerly ice flow during glacial maxima, traces of preglacial valleys have been more severely modified by glacial erosion in diverging directions. Striations in the region record three such diverging ice-flow directions of the last ice sheet. In one quarry, the position and cross-cutting erosional relationships of the three striation sets indicate their relative ages, from oldest to youngest: SSW, SW, and W. The SSW-trending set is overlain by a compact, loamy till containing abundant Canadian-shield crystalline gravel clasts. The till and the striations record the initial Late Wisconsinan ice advance into the region. The younger striation sets are overlain by the clayey, shale-rich till of the Erie lobe. Onshore, glaciolacustrine massive silty clay overlies the clayey till and fills broad troughs between areas of till at the surface. Offshore, seismic profiles reveal stratification in the clay, which is overlain by late Holocene mud. A nearby test hole through the beach west of Turtle Creek suggests a valley-fill sequence consisting of Late Wisconsinan till overlain by 5 m of organic mud deposited during the late Holocene transgression of Late Erie.

  14. Gravity and magnetic studies of the Geysers-Clear Lake geothermal region, California, USA

    USGS Publications Warehouse

    Isherwood, William F.

    1976-01-01

    Gravity and magnetic fields in The Geysers-Clear Lake region are interpreted in relation to the known geology and other available geophysical data. New gravity data provide additional detail with the area of geothermal steam production. Computer techniques were used for removal of the regional gravity field, anomaly enhancement, and modeling subsurface structures. The gravity field was separated into three components: (1) a regional field presumed to be due to deep crustal structure related to the continental margin; (2) a residual gravity low of approximately 30 mgal centered over Mount Hannah and having an approximate diameter of 20 km, which is caused, according to our model, by a magma chamber whose top lies within 10 km of the surface; and (3) a closed residual low over the original steam production field. This low is probably related to effects within 1.5 km of the surface and was modeled as a steam-saturated reservoir structure. Local magnetic highs correlate with surface outcrops of serpentinite and relief on the volcanic rocks. Upward continuation of the aeromagnetic data suggests that the serpentinite body along the Collayomi fault may extend to a depth of more than 3 km near Boggs Mountain, but that other serpentinite bodies are probably more shallow. A long-wavelength magnetic high (centered at ~39°03'N 122°33'W) and a magnetic low (centered at ~38°:43'N 122°47'W) give half-width depth estimates of about 10 km. The center of the Mount Hannah gravity low lies in an area between these features and appears devoid of deep magnetic expression.

  15. Climate Induced Birch Mortality in Trans-Baikal Lake Region, Siberia

    NASA Technical Reports Server (NTRS)

    Kharuk, V. I.; Ranson, K. J.; Oskorbin, P. A.; Im, S. T.; Dvinskaya, M. L.

    2013-01-01

    The Trans-Baikal (or Zabailkal'e) region includes the forest-steppe ecotones south and east of Lake Baikal in Russia and has experienced drought for several years. The decline and mortality of birch (Betula pendula) stands within the forest-steppe ecotone Trans-Baikal region was studied based on a temporal series of satellite data, ground measurements, and tree ring analysis. During the first decade of the 21st century birch stands decline and mortality were observed on )about 5% of the total area of stands within our 1250 km(exp 2 study area. Birch forest decline and mortality occurs mainly at the margins of stands, within the forest-steppe ecotone on slopes with direct insolation. During the first decade of the 21st century summer (June-August) precipitation was about 25% below normal. Soil water content measurements were lowest within dead stands and highest within healthy stands and intermediate within damaged stands. Drought impact on stands was amplified by an increase in summer air temperatures (+0.9 C) in comparison with the previous decade. Tree ring data of ''surviving'' and ''dead'' tree groups showed a positive correlation with summer/annual precipitation and negative correlation with summer air temperatures. Temperature and precipitation extreme anomalies tend to occur in the region with a period of about 27 years. The observed anomaly was the most severe since the beginning of meteorological observations in the year 1900. Data for the other sites showed a positive climate impact on the growth and expansion of Siberian forests. That is, the same species (B. pendula) showed considerable increase (1.4 times both in height and stem volume) during 20th-21st centuries as temperature increased but precipitation remained at adequate levels.

  16. Hydroecological condition and potential for aquaculture in lakes of the arid region of Khorezm, Uzbekistan

    USGS Publications Warehouse

    Crootof, Africa; Mullabaev, Nodirbek; Saito, Laurel; Atwell, Lisa; Rosen, Michael R.; Bekchonova, Marhabo; Ginatullina, Elena; Scott, Julian; Chandra, Sudeep; Nishonov, Bakhriddin; Lamers, John P.A.; Fayzieva, Dilorom

    2015-01-01

    With >400 small (<1 ha) lakes, the arid Khorezm Province in Uzbekistan may be well-suited for aquaculture production. Developing water resources to provide a local food supply could increase fish consumption while improving the rural economy. Hydroecological (biological and physical) and chemical characteristics (including legacy pesticides ΣDDT and ΣHCH) of four representative drainage lakes in Khorezm from 2006 to 2008 were analyzed for the lakes’ capability to support healthy fish populations. Lake characteristics were categorized as “optimal” (having little or no effect on growth and development), “tolerable” (corresponding to chronic or sub-lethal toxicity) and “lethal” (corresponding to acute toxicity). Results indicate that three lakes are likely well-suited for raising fish species, with water quality meeting World Bank aquaculture guidelines. However, the fourth lake often had salinity concentrations > optimal levels for local fish species. Pesticide concentrations in water of all four lakes were within tolerable aquaculture ranges. Although water ΣDDT concentrations were >optimal limits, results from chemical analysis of fish tissues and semi-permeable membrane devices indicated that study lake ΣDDT concentrations were not accumulating in fish or posing a human health threat. Land and water management to maintain adequate lake water quality are imperative for sustaining fish populations for human consumption.

  17. Global and regional contributions to total mercury concentrations in Lake Michigan water

    EPA Science Inventory

    A calibrated mercury component mass balance model, LM2-Mercury, was applied to Lake Michigan to predict mercury concentrations in the lake under different mercury loadings, mercury air concentrations, and management scenarios. Although post-audit data are few, model predictions (...

  18. INTERPRETING PATTERNS OF LAKE ALKALINITY IN THE UPPER MIDWEST REGION, USA

    EPA Science Inventory

    To clarify the extent of sensitivity of surface waters to acidic deposition in Minnesota, Wisconsin, and Michigan, lake and stream patterns were mapped for alkalinity. Data was analyzed from approximately 14,000 lakes and streams and evaluated for the apparent spatial association...

  19. Scaling up carbon storage in human-dominated heterogeneous landscapes in the Great Lakes region

    NASA Astrophysics Data System (ADS)

    Currie, W.; Brown, D. G.; Kiger, S.; Nassauer, J. I.; Robinson, D. T.

    2013-12-01

    partly from the presence of turfgrasses and old-field vegetation. The Great Lakes region has a 150-year history of land cover conversions among forest, agriculture, residential land, and managed and un-managed heterogeneous reforestation and fragmentation. Our results highlight the importance of confronting human-caused heterogeneity in the scaling of C pools and C trajectories in the region.

  20. EVALUATING REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL, REGIONAL-MERCURY CYCLING MODEL (R-MCM), APPLIED TO 91 VERMONT AND NEW HAMPSHIRE LAKES AND PONDS, USA

    EPA Science Inventory

    Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The Regional Mercury Cycling model (R-MCM) was specifically d...

  1. Changing land use and its impact on the habitat suitability for wintering Anseriformes in China's Poyang Lake region.

    PubMed

    Tang, Xuguang; Li, Hengpeng; Xu, Xibao; Yang, Guishan; Liu, Guihua; Li, Xinyan; Chen, Dongqiang

    2016-07-01

    As an internationally important wetland for migratory waterbirds, China's Poyang Lake region has experienced substantial changes in land use during the past two decades owing to climate change and anthropogenic disturbances. Recent dam constructions on the Yangtze River and its tributaries for agriculture and hydroelectric power exert strong effects on the hydrological regimes of this lake. However, few studies have investigated how the land-use changes through time affect the habitat suitability for wintering Anseriformes-the largest community in this region. Thus, it is necessary to timely monitor changes in the habitat quality and understand the potential factors that alter it. In this study, three periods (1995, 2005 and 2014) of typical environmental indicators that have direct impacts on foraging and resting for the Anserformes, including proximity to water (density of lakes, rivers and ponds), human disturbances (density of residences and various road networks), preferred land cover types and food availability (NDVI), are integrated to develop a habitat suitability index model for habitat mapping. The results indicate that long-term lake shrinkage in low-water periods led to greatly expanded wetlands in these years, which provided more suitable habitat for migratory waterfowl. The amount of highly suitable habitat in 2014 was nearly twice as much as in 1995. Recent survey data from 1997 to 2013 also revealed an increase in the population size, and confirmed the improvement of habitat suitability in the Poyang Lake region. Spatial analysis revealed that land use changes contributed most to the improved habitat coverage between 1995 and 2014. However, the relative significances of these transformations for highly suitable and moderately suitable habitats are strikingly different. Increases in wetland and paddy field area are the main reasons for explaining these improvements, respectively. The framework model proposed in this study will help governments to

  2. Glacio-lacustrine facies of the Finger Lakes region of New York state

    SciTech Connect

    Wellner, R.W.; Mullins, H.T. . Dept. of Geology)

    1993-03-01

    A high-resolution (< 1 m), Uniboom seismic reflection survey ([approximately]1,500 km) of the eleven lakes that comprise the Finger Lakes of central New York State has revealed the nature of the thick (270 m at a maximum) glacio-lacustrine sediment-fill beneath the lakes. These seismic data have been ground truthed via piston cores from Seneca and Cayuga Lakes, as well as drillcore and geophysical data from the dry valley south ([approximately]3 km) of Canandaigua Lake, and outcrop exposures. Six depositional sequences, each with distinct acoustic characteristics, have been recognized. The oldest sequence (1) typically occurs in the southern third of each lake basin where it is as much as 100+ m thick. It is characterized by a chaotic facies and is correlated with outcrops of the stratified, waterlain drift of the Valley Heads Moraine. Sequence 2 is characterized by a lateral change from a chaotic (north) to reflection-free or transparent (south) facies. Piston cores from an esker-like ridge in Cayuga Lake recovered fine-grained rhythmites with dropstones before bottoming in a clast-supported gravel. Sequence 3 is characterized by an acoustically transparent facies. Although this sequence was not sampled, this seismic facies suggests rapidly deposited, fine-grained sediments. Sequence 4 is characterized by continuous parallel, high-frequency reflections. Drillcore south of Canandaigua Lake recovered a coarsening-upward sequence of sands and gravels (with artesian water). Sequence 6 is characterized throughout each lake basin by a low amplitude to acoustically transparent facies. In general, the sedimentary record beneath the Finger Lakes reflects an overall change from high-energy, subglacial deposition to lower energy, proglacial deposition as a result of the northward retreat of the Laurentide Ice Sheet during Termination 1A of the marine record.

  3. Deep drilling of ancient Lake Ohrid (Balkan region) to capture over 1 million years of evolution and global climate cycling

    NASA Astrophysics Data System (ADS)

    Wagner, Bernd; Francke, Alexander; Wilke, Thomas; Krastel, Sebastian; Zanchetta, Giovanni; Sulpizio, Roberto; Reicherter, Klaus; Leng, Melanie; Grazhdani, Andon; Trajanovski, Sasho; Levkov, Zlatko; Reed, Jane; Wonik, Thomas

    2014-05-01

    Ancient lakes, with sediment records spanning >1 million years, are very rare. The UNESCO World Heritage site of Lake Ohrid in the Balkan region is thought to be the oldest lake in continuous existence in Europe and, with 212 endemic species described to date, is a hotspot of evolution. An international group of scientists working on a project entitled 'Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO)' realized a deep drilling campaign of Lake Ohrid in spring 2013. Based on several coring seismic campaigns between 2004 and 2011, Lake Ohrid became the target of an ICDP deep drilling campaign, with specific research aims: (i) obtain precise information about the age and origin of the lake, (ii) unravel the lake's seismotectonic history, (iii) obtain a continuous record of Quaternary volcanic activity and climate change, and (iv) investigate the influence of major geological/environmental events on evolution and the generation of extraordinary endemic biodiversity. Drilling began in April 2013 using the Deep Lake Drilling System (DLDS) of DOSECC (USA). The campaign, completed by late May, was deemed one of the most successful ICDP lake drilling projects, with a total of ~2100 m of sediment recovered from four different sites. At the central "DEEP" site, hydro-acoustic data indicated a maximum sediment fill of ca. 700 m, of which the uppermost 568 m was recovered. Coarse gravel and pebbles underlying clay and shallow water facies hampered deeper penetration. A total of 1526 m of sediment cores was collected from six boreholes, with a composite field recovery ('master core') of 544 m (95%). Three additional sites were drilled in order to analyze lake-level fluctuations, catchment dynamics, biodiversity and evolution processes ("Cerava", deepest drilled depth: 90 m), to investigate active tectonics and spring dynamics ("Gradiste", deepest drilled depth: 123 m), and to try to understand the geological origins of the Ohrid Basin ("Pestani

  4. [Spatial Distribution Characteristics of Different Species Mercury in Water Body of Changshou Lake in Three Gorges Reservoir Region].

    PubMed

    Bai, Wei-yang; Zhang, Cheng; Zhao, Zheng; Tang, Zhen-ya; Wang, Ding-yong

    2015-08-01

    An investigation on the concentrations and the spatial distribution characteristics of different species of mercury in the water body of Changshou Lake in Three Gorges Reservoir region was carried out based on the AreGIS statistics module. The results showed that the concentration of the total mercury in Changshou Lake surface water ranged from 0.50 to 3.78 ng x L(-1), with an average of 1.51 ng x L(-1); the concentration of the total MeHg (methylmercury) ranged from 0.10 to 0.75 ng x L(-1), with an average of 0.23 ng x L(-1). The nugget effect value of total mercury in surface water (50.65%), dissolved mercury (49.80%), particulate mercury (29.94%) and the activity mercury (26.95%) were moderate spatial autocorrelation. It indicated that the autocorrelation was impacted by the intrinsic properties of sediments (such as parent materials and rocks, geological mineral and terrain), and on the other hand it was also disturbed by the exogenous input factors (such as aquaculture, industrial activities, farming etc). The nugget effect value of dissolved methylmercury (DMeHg) in Changshou lake surface water (3.49%) was less than 25%, showing significant strong spatial autocorrelation. The distribution was mainly controlled by environmental factors in water. The proportion of total MeHg in total Hg in Changshou Lake water reached 30% which was the maximum ratio of the total MeHg to total Hg in freshwater lakes and rivers. It implied that mercury was easily methylated in the environment of Chanashou Lake. PMID:26592014

  5. Extreme precipitation and beach closures in the great lakes region: evaluating risk among the elderly.

    PubMed

    Bush, Kathleen F; Fossani, Cheryl L; Li, Shi; Mukherjee, Bhramar; Gronlund, Carina J; O'Neill, Marie S

    2014-02-01

    As a result of climate change, extreme precipitation events are expected to increase in frequency and intensity. Runoff from these extreme events poses threats to water quality and human health. We investigated the impact of extreme precipitation and beach closings on the risk of gastrointestinal illness (GI)-related hospital admissions among individuals 65 and older in 12 Great Lakes cities from 2000 to 2006. Poisson regression models were fit in each city, controlling for temperature and long-term time trends. City-specific estimates were combined to form an overall regional risk estimate. Approximately 40,000 GI-related hospital admissions and over 100 beach closure days were recorded from May through September during the study period. Extreme precipitation (≥90th percentile) occurring the previous day (lag 1) is significantly associated with beach closures in 8 of the 12 cities (p < 0.05). However, no association was observed between beach closures and GI-related hospital admissions. These results support previous work linking extreme precipitation to compromised recreational water quality. PMID:24534768

  6. [Role of human and domestic animal reservoirs of schistosomiasis japonica in Dongting and Boyang Lake regions].

    PubMed

    Wu, Z W; Liu, Z D; Pu, K M; Hu, G H; Zhou, S J; Zhou, S Y; Zhang, S J; Yuan, H C

    1992-01-01

    In Dongting and Boyang Lake regions, the main reservoirs of schistosomiasis were farm cattle (mostly buffaloes), pigs and mobile nonnatives. However, the role of these reservoirs in different types of endemic areas were not the same in the transmission of schistosomiasis. In islet-beach type area, the main infectious sources were pigs and local residents. The proportion of IRC (Index of Real Contamination) of local residents and pigs to the total IRC was 30.9% and 39.9% respectively. In fork-beach type area having luxuriant grass and abundant aquatic products, there were a number of buffaloes and people from other places. The proportion of IRC of the nonnative buffaloes and mobile nonnatives made up 51.9% and 21.8% of the total IRC respectively, the main reservoirs being from other places. The embankment-beach type area had a vast snail-infected area and a large number of buffaloes from both local and other places as well as mobile nonnatives. The proportion of IRC of buffaloes and nonnatives made up 69.8% and 21.4% of the total IRC respectively, serving as the main reservoirs. As regard to season differences, the infected buffaloes were the main reservoirs during dry seasons, especially from March to May, whereas the mobile nonnatives including fishermen and boatmen were the main infectious sources during flood seasons from June to October. PMID:1307274

  7. Fish consumption among women anglers of childbearing age in the Great Lakes region.

    PubMed

    Connelly, Nancy A; Bruce Lauber, T; Niederdeppe, Jeff; Knuth, Barbara A

    2016-10-01

    Fish consumption advisories are issued by the federal government for women of childbearing age (WCBA). These advisories make recommendations about the amount and types of fish that should be consumed to provide the greatest health benefits to women and their children while avoiding risks from chemical contaminants. We used diary methods to study fish consumption patterns of 1395 WCBA in the Great Lakes coastal region who purchased fishing licenses, a group which has significant opportunity to eat larger quantities of fish. Very few members of this group reported exceeding the federal recommendations for total fish consumption (between 3% and 5% depending on assumptions about portion sizes), consumption of canned "white" tuna (0%), or consumption of "do not eat" species (4%). They did report eating more fish on average than recent national study estimates, but they did not report consuming as much fish as is recommended to obtain the greatest health benefits of fish consumption. Only 10-12% of study participants reported eating within the recommended range of 8-12oz. of fish per week, with 84-87% eating less than the recommended amount. Additional efforts are likely needed to encourage WCBA to eat more low-risk fish, even among this group of higher-than-average fish consumers. PMID:27309721

  8. Best Practices for Wind Energy Development in the Great Lakes Region

    SciTech Connect

    Pebbles, Victoria; Hummer, John; Haven, Celia

    2011-07-19

    This report offers a menu of 18 different, yet complementary, preferred practices and policies. The best practices cover all phases of the wind energy development process - from the policies that allow for wind development, to the sustainable operation of a wind project, to the best practices for decommissioning a spent turbine - including applications for offshore wind. Each best practice describes the opportunities and challenges (pros and cons), and offers a case example that illustrates how that best practice is being utilized by a particular jurisdiction or wind project. The practices described in this publication were selected by a diverse group of interests from the Great Lakes Wind Collaborative that included environmental groups, industry, academia, and federal, state and local government regulators. The practices were identified through a year-long process that included a literature review, online survey and interviews with individuals from the public, private and non-profit sectors. Optimally, a suite of these best practices would be applied in an appropriate combination to fit the conditions of a particular wind project or a set of wind projects within a given locality or region.

  9. Midcontinent rift volcanism in the Lake Superior region: Sr, Nd, and Pb isotopic evidence for a mantle plume origin

    SciTech Connect

    Nicholson, S.W. Univ. of Minnesota, MN ); Shirey, S.B. )

    1990-07-10

    Between 1091 and 1098 Ma, most of a 15- to 20-km thickness of dominantly tholeiitic basalt erupted in the Midcontinent Rift System of the Lake Superior region, North American. The Portage Lake Volcanics in Michigan, which are the youngest MRS flood basalts, fall into distinctly high- and low-TiO{sub 2} types having different liquid lines of descent. Incompatible trace elements in both types of tholeiites are enriched compared to depleted or primitive mantle (La/Yb = 4.3-5.3; Th/Ta = 2.12-2.16; Zr/Y = 4.3-4.4), and both basalt types are isotopically indistinguishable. Sr, Nd, and Pb isotopic compositions of the Portage Lake tholeiites have {sup 87}Sr/{sup 86}Sr{sub i} {approx}0.7038, {epsilon}{sub Nd(1095 Ma)} {approx}0 {plus minus} 2, and {mu}{sub 1} {approx}8.2. Model ages with respect to a depleted mantle source (T{sub DM}) average about 1950-2100 Ma. Portage Lake rhyolits fall into two groups. Type I rhyolites have Nd and Pb isotopic characteristics ({epsilon}{sub Nd(1095 Ma)} {approx}0 to {minus}4.7; {mu}{sub 1} {approx}8.2-7.8) consistent with contamination of tholeiitic rocks by 5-10% Archean crust. The one type II rhyolite analyzed has Nd and Pb isotopic compositions ({epsilon}{sub Nd(1095 Ma)} {approx}{minus}13 to {minus}16; {mu}{sub 1} {approx}7.6-7.7) which are consistent with partial melting of Archean crust. Early Proterozoic crust was not a major contaminant of MRS rocks in the Lake Superior region. Most reported Nd and Pb isotopic compositions of MRS tholeiites from the main stage of volcanism in the Lake Superior region and of the Duluth Complex are comparable to the Nd and Pb isotopic data for Portage lake tholeiites. The isotopic enrichment of the MRS source compared to depleted mantle is striking and must have occurred at least 700 m.y. before 1100 Ma.

  10. Spatially explicit exposure assessment for small streams in catchments of the orchard growing region `Lake Constance

    NASA Astrophysics Data System (ADS)

    Golla, B.; Bach, M.; Krumpe, J.

    2009-04-01

    1. Introduction Small streams differ greatly from the standardised water body used in the context of aquatic risk assessment for the regulation of plant protection products in Germany. The standard water body is static, with a depth of 0.3 m and a width of 1.0 m. No dilution or water replacement takes place. Spray drift happens always in direction to the water body. There is no variability in drift deposition rate (90th percentile spray drift deposition values [2]). There is no spray drift filtering by vegetation. The application takes place directly adjacent to the water body. In order to establish a more realistic risk assessment procedure the Federal Office for Consumer Protection and Food Safety (BVL) and the Federal Environment Agency (UBA) aggreed to replace deterministic assumptions with data distributions and spatially explicit data and introduce probabilistic methods [3, 4, 5]. To consider the spatial and temporal variability in the exposure situations of small streams the hydraulic and morphological characteristics of catchments need to be described as well as the spatial distribution of fields treated with pesticides. As small streams are the dominant type of water body in most German orchard regions, we use the growing region Lake Constance as pilot region. 2. Materials and methods During field surveys we derive basic morphological parameters for small streams in the Lake Constance region. The mean water width/depth ratio is 13 with a mean depth of 0.12 m. The average residence time is 5.6 s/m (n=87) [1]. Orchards are mostly located in the upper parts of the catchments. Based on an authoritative dataset on rivers and streams of Germany (ATKIS DLM25) we constructed a directed network topology for the Lake Constance region. The gradient of the riverbed is calculated for river stretches of > 500 m length. The network for the pilot region consists of 2000 km rivers and streams. 500 km stream length are located within a distance of 150 m to orchards. Within

  11. Distribution and diversity of diatom assemblages in surficial sediments of shallow lakes in Wapusk National Park (Manitoba, Canada) region of the Hudson Bay Lowlands.

    PubMed

    Jacques, Olivier; Bouchard, Frédéric; MacDonald, Lauren A; Hall, Roland I; Wolfe, Brent B; Pienitz, Reinhard

    2016-07-01

    The hydrology of shallow lakes (and ponds) located in the western Hudson Bay Lowlands (HBL) is sensitive to climate warming and associated permafrost thaw. However, their biological characteristics are poorly known, which hampers effective aquatic ecosystem monitoring. Located in northern Manitoba along the southwestern coast of Hudson Bay, Wapusk National Park (WNP) encompasses numerous shallow lakes representative of the subarctic zone. We analyzed the distribution and diversity of diatom (microscopic algae; class Bacillariophyceae) assemblages in surficial sediments of 33 lakes located in three different ecozones spanning a vegetation gradient, from NE to SW: the Coastal Fen (CF), the Interior Peat Plateau (IPP), and the Boreal Spruce Forest (BSF). We found significant differences (P < 0.05) in diatom community composition between CF and IPP lakes, and CF and BSF lakes, but not between IPP and BSF lakes. These results are consistent with water chemistry measurements, which indicated distinct limnological conditions for CF lakes. Diatom communities in CF lakes were generally dominated by alkaliphilous taxa typical of waters with medium to high conductivity, such as Nitzschia denticula. In contrast, several IPP and BSF lakes were dominated by acidophilous and circumneutral diatom taxa with preference for low conductivity (e.g., Tabellaria flocculosa, Eunotia mucophila, E. necompacta var. vixcompacta). This exploratory survey provides a first detailed inventory of the diatom assemblages in the WNP region needed for monitoring programs to detect changes in shallow lake ecosystems and ecozonal shifts in response to climate variations. PMID:27386094

  12. Geochemical and isotopic (Sr, U) variations of lake waters in the Ol'khon Region, Siberia, Russia: Origin and paleoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Chabaux, François; Granet, Mathieu; Larqué, Philippe; Riotte, Jean; Skliarov, Eugeni V.; Skliarova, Olga; Alexeieva, Ludmilla; Risacher, François

    2011-07-01

    The geochemical study of springs and lake waters from the Ol'khon Region, Siberia, confirms the strong chemical variability of these water samples, more particularly regarding their salinity. Such variability does not result from a simple mixing process between surface freshwaters and deeper saline waters. The variability, observed at the scale of a few square kilometers, would preferentially result from a secondary concentration processes (evaporation and/or cryogenesis) of lake waters of variable intensity from one lake to another. The U-disequilibria data suggest that the duration of the secondary process is certainly an important parameter to be considered to account for the variable salinity of these lakes. The data indicate that the lakes, however modest in size, could be as old as several ky, confirming therefore that the lake sedimentary deposits could represent relevant paleoenvironmental recorders for the last thousands years.

  13. Using existing data to estimate aquifer properties, Great Lakes Region, USA

    USGS Publications Warehouse

    Darner, Robert A.; Sheets, Rodney A.

    2012-01-01

    To determine specific storage and porosity, areally limited and time-consuming aquifer tests are frequently done. Hydrogeologic studies often do not have the resources to collect such data and rely on existing data sources for aquifer properties. An alternative tool for determining these aquifer properties is the analysis of earth tides. The objective of this study was to determine whether existing water-level and barometric-pressure data could be used to determine aquifer properties, such as porosity and specific storage, on a regional scale. In this study, national databases from the Great Lakes Region were queried for continuous records of groundwater-level and barometric-pressure data. Records from 37 selected wells were then analyzed for barometric efficiency and earth-tide responses. Specific-storage (Ss) and porosity values were determined, and the quality of the results were assessed with a measure of the "goodness of fit" (percent variance) of reconstruction of the response. Records from wells completed in several aquifer systems were analyzed with varying degrees of success. Aquifer Ss values ranging from 5.9 x 10-8 to 3.8 x 10-6/m were derived, with percent variance of reconstruction ranging from 1% to 78%. Comparisons with aquifer and laboratory testing of Ss and porosity are favorable if the percent variance of reconstruction is above about 30%. Although the earth-tide-analysis method is not suitable for every situation, the Ss and porosity of aquifers can, in many places, be estimated with existing water-level and barometric-pressure data or with data that are relatively inexpensive to collect.

  14. Modeled aerosol nitrate formation pathways during wintertime in the Great Lakes region of North America

    NASA Astrophysics Data System (ADS)

    Kim, Yoo Jung; Spak, Scott N.; Carmichael, Gregory R.; Riemer, Nicole; Stanier, Charles O.

    2014-11-01

    Episodic wintertime particle pollution by ammonium nitrate is an important air quality concern across the Midwest U.S. Understanding and accurately forecasting PM2.5 episodes are complicated by multiple pathways for aerosol nitrate formation, each with uncertain rate parameters. Here, the Community Multiscale Air Quality model (CMAQ) simulated regional atmospheric nitrate budgets during the 2009 LADCO Winter Nitrate Study, using integrated process rate (IPR) and integrated reaction rate (IRR) tools to quantify relevant processes. Total nitrate production contributing to PM2.5 episodes is a regional phenomenon, with peak production over the Ohio River Valley and southern Great Lakes. Total nitrate production in the lower troposphere is attributed to three pathways, with 57% from heterogeneous conversion of N2O5, 28% from the reaction of OH and NO2, and 15% from homogeneous conversion of N2O5. TNO3 formation rates varied day-to-day and on synoptic timescales. Rate-limited production does not follow urban-rural gradients and NOx emissions due, to counterbalancing of urban enhancement in daytime HNO3 production with nocturnal reductions. Concentrations of HNO3 and N2O5 and nighttime TNO3 formation rates have maxima aloft (100-500 m), leading to net total nitrate vertical flux during episodes, with substantial vertical gradients in nitrate partitioning. Uncertainties in all three pathways are relevant to wintertime aerosol modeling and highlight the importance of interacting transport and chemistry processes during ammonium nitrate episodes, as well as the need for additional constraint on the system through field and laboratory experiments.

  15. Mosaic maternal ancestry in the Great Lakes region of East Africa.

    PubMed

    Gomes, Verónica; Pala, Maria; Salas, Antonio; Álvarez-Iglesias, Vanesa; Amorim, António; Gómez-Carballa, Alberto; Carracedo, Ángel; Clarke, Douglas J; Hill, Catherine; Mormina, Maru; Shaw, Marie-Anne; Dunne, David W; Pereira, Rui; Pereira, Vânia; Prata, Maria João; Sánchez-Diz, Paula; Rito, Teresa; Soares, Pedro; Gusmão, Leonor; Richards, Martin B

    2015-09-01

    The Great Lakes lie within a region of East Africa with very high human genetic diversity, home of many ethno-linguistic groups usually assumed to be the product of a small number of major dispersals. However, our knowledge of these dispersals relies primarily on the inferences of historical, linguistics and oral traditions, with attempts to match up the archaeological evidence where possible. This is an obvious area to which archaeogenetics can contribute, yet Uganda, at the heart of these developments, has not been studied for mitochondrial DNA (mtDNA) variation. Here, we compare mtDNA lineages at this putative genetic crossroads across 409 representatives of the major language groups: Bantu speakers and Eastern and Western Nilotic speakers. We show that Uganda harbours one of the highest mtDNA diversities within and between linguistic groups, with the various groups significantly differentiated from each other. Despite an inferred linguistic origin in South Sudan, the data from the two Nilotic-speaking groups point to a much more complex history, involving not only possible dispersals from Sudan and the Horn but also large-scale assimilation of autochthonous lineages within East Africa and even Uganda itself. The Eastern Nilotic group also carries signals characteristic of West-Central Africa, primarily due to Bantu influence, whereas a much stronger signal in the Western Nilotic group suggests direct West-Central African ancestry. Bantu speakers share lineages with both Nilotic groups, and also harbour East African lineages not found in Western Nilotic speakers, likely due to assimilating indigenous populations since arriving in the region ~3000 years ago. PMID:26188410

  16. Genetic analysis of historic western Great Lakes region wolf samples reveals early Canis lupus/lycaon hybridization

    PubMed Central

    Wheeldon, Tyler; White, Bradley N.

    2008-01-01

    The genetic status of wolves in the western Great Lakes region has received increased attention following the decision to remove them from protection under the US Endangered Species Act. A recent study of mitochondrial DNA has suggested that the recovered wolf population is not genetically representative of the historic population. We present microsatellite genotype data on three historic samples and compare them with extant populations, and interpret published genetic data to show that the pre-recovery population was admixed over a century ago by eastern wolf (Canis lycaon) and grey wolf (Canis lupus) hybridization. The DNA profiles of the historic samples are similar to those of extant animals in the region, suggesting that the current Great Lakes wolves are representative of the historic population. PMID:18940770

  17. Regional Integrated Lake-Watershed Acidification Study (RILWAS): Major findings for Adirondack and Blue Ridge Mountains

    SciTech Connect

    Gherini, S.A.; Munson, R.K. ); Altwicker, E.; Clesceri, N. ); April, R. ); Chen, C.W. ); Cronan, C.S. ); Driscoll, C.T. ); Johannes, A.H. ); Newton, R.M.

    1989-12-01

    The primary objective of this investigation was to test the hydrologic and chemical theory developed during the Integrated Lake Watershed Acidification Study (ILWAS). A secondary objective was to assess the distribution of fish species among lakes of varying water quality. A total of 24 lake-watershed systems across the Adirondacks served as stuey sites over a period of two years. The US Forest Service's, Coweeta Hydrologic Laboratory, with over 20 years of data, was used to test the ILWAS model on a Blue Ridge mountain stream. 122 refs., 123 figs., 46 tabs.

  18. A link between North Atlantic cooling and dry events in the core SW monsoon region in Lonar Lake, central India

    NASA Astrophysics Data System (ADS)

    Menzel, Philip; Gaye, Birgit; Prasad, Sushma; Plessen, Birgit; Stebich, Martina; Anoop, Ambili; Riedel, Nils; Basavaiah, Nathani

    2014-05-01

    A sediment core from Lonar Lake in central India covers the complete Holocene and was used to reconstruct the monsoon history of the core SW-monsoon region. We compare C/N ratios, stable carbon and nitrogen isotopes, grain size, as well as amino acid derived degradation proxies with climatically sensitive proxies of other records from South Asia and the North Atlantic region. The comparison reveals some more or less contemporaneous climate shifts. At Lonar Lake, a general long term climate transition from wet conditions during the early Holocene to drier conditions during the late Holocene, delineating the insolation curve, can be reconstructed. Several phases of shorter term climate alteration that superimpose the general climate trend correlate with cold phases in the North Atlantic region. The most pronounced climate deteriorations indicated by our data occurred between 6.2 - 5.2, 4.65 - 3.9, and 2.05 - 0.55 cal ka BP. The strong dry phase between 4.65 - 3.9 cal ka BP at Lonar Lake corroborates the hypothesis that severe climate deterioration contributed to the decline of the Indus Civilisation about 3.9 ka BP.

  19. Genetic features of soils in the basin of Lake Kotokel, the Transbaikal region

    NASA Astrophysics Data System (ADS)

    Balsanova, L. D.; Gyninova, V. B.; Tsybikdorzhiev, Ts. Ts.; Gonchikov, B.-M. N.; Shakhmatova, E. Yu.

    2014-07-01

    The diversity of the soils and the specific features of the pedogenesis in the basin of Lake Kotokel have been studied. The specificity of the pedogenesis and soil cover patterns in the lake basin are controlled by the altitudinal zonation, the diversity of parent materials, and the influence of air masses from Lake Baikal. Gray metamorphic soils and raw-humus burozems developed under taiga vegetation in the mountains predominate in the basin of Lake Kotokel. The coastal landscapes and river valleys are occupied by swampy and meadow alluvial soils. The genetic features of the major soils have been characterized on the basis of field descriptions, laboratory data, and special macro- and micromorphological studies.

  20. Development of a regional glycerol dialkyl glycerol tetraether (GDGT)-temperature calibration for Antarctic and sub-Antarctic lakes

    NASA Astrophysics Data System (ADS)

    Foster, Louise C.; Pearson, Emma J.; Juggins, Steve; Hodgson, Dominic A.; Saunders, Krystyna M.; Verleyen, Elie; Roberts, Stephen J.

    2016-01-01

    A regional network of quantitative reconstructions of past climate variability is required to test climate models. In recent studies, temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have enabled past temperature reconstructions in both marine and terrestrial environments. Nevertheless, to date these methods have not been widely applied in high latitude environments due to poor performance of the GDGT-temperature calibrations at lower temperatures. To address this we studied 32 lakes from Antarctica, the sub-Antarctic Islands and Southern Chile to: 1) quantify their GDGT composition and investigate the environmental controls on GDGT composition; and 2) develop a GDGT-temperature calibration model for inferring past temperatures from Antarctic and sub-Antarctic lakes. GDGTs were found in all 32 lakes studied and in 31 lakes branched GDGTs (brGDGTs) were the dominant compounds. Statistical analyses of brGDGT composition in relation to temperature, pH, conductivity and water depth showed that the composition of brGDGTs is strongly correlated with mean summer air temperature (MSAT). This enabled the development of the first regional brGDGT-temperature calibration for use in Antarctic and sub-Antarctic lakes using four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). A key discovery was that GDGT-IIIb is of particular importance in cold lacustrine environments. The addition of this compound significantly improved the model's performance from r2 = 0.67, RMSEP-LOO (leave-one-out) = 2.23 °C, RMSEP-H (h-block) = 2.37 °C when applying the re-calibrated global GDGT-temperature calibration to our Antarctic dataset to r2 = 0.83, RMSEP-LOO = 1.68 °C, RMSEP-H = 1.65 °C for our new Antarctic calibration. This shows that Antarctic and sub-Antarctic, and possibly other high latitude, palaeotemperature reconstructions should be based on a regional GDGT-temperature calibration where specific

  1. Tree-Ring Proxies of Hydroclimate Variability in the Great Lakes Region during Cold Excursions Back to 15ka

    NASA Astrophysics Data System (ADS)

    Panyushkina, I. P.; Leavitt, S. W.

    2014-12-01

    A decade-long investigation of subfossil wood buried in glacio-fluvial, fluvial and lacustrine deposits from the U.S. Great Lakes region has resulted in a Great Lakes tree-ring network (GLTRN) comprising 47 sites dated from ca. 15 ka to 3ka. The GLTRN provides high-resolution proxies for exploration of local and regional responses to hydroclimate change at inter-annual scales during the transition from the Late Pleistocene to the Holocene. Classification of radiometric ages of GLTRN wood with relative cumulative-probability function delineates intervals and importance of hydrological changes in time and space. The overwhelming majority of wood burial events correlate with generally cold climate excursions. Forest-stand deterioration and tree mortality events at the studied sites are demonstrated to result from flooding, via river aggradation (identifying occurrence of extreme hydrologic events), rise of water table, or lake inundation. To better evaluate the special patterns of hydrological change back to 15ka, we developed four floating d13C chronologies from spruce tree rings. The length of these tree-ring proxy series that capture high-frequency moisture variability of the Great Lakes area ranges from 120 to 250 years. Our data indicate progressive wet intervals during the cold excursions precisely dated with 14C tree-ring wiggles at 13.7ka, 12.1ka, and 11.3ka that fall in the Bølling-Allerød and Pre-Boreal Interstadials, and Younger Dryas Stadial. The inter-annual and decadal variability of tree-ring moisture proxies are similar across the studied locations and time intervals. Such coherence of respective proxies may result from both local ecological stability of spruce communities or regional response to a common source of moisture at the studied time intervals and locations. This study demonstrates a potential of GLTRN proxies for modeling hydroclimatic changes at the North American continent back 15 ka.

  2. The Water Level Fall of Lake Megali Prespa (N Greece): an Indicator of Regional Water Stress Driven by Climate Change and Amplified by Water Extraction?

    NASA Astrophysics Data System (ADS)

    van der Schriek, Tim; Giannakopoulos, Christos

    2014-05-01

    The Mediterranean stands out globally due to its sensitivity to (future) climate change, with future projections predicting an increase in excessive drought events and declining rainfall. Regional freshwater ecosystems are particularly threatened: precipitation decreases, while extreme droughts increase and human impacts intensify (e.g. water extraction, drainage, pollution and dam-building). Many Mediterranean lake-wetland systems have shrunk or disappeared over the past two decades. Protecting the remaining systems is extremely important for supporting global biodiversity and for ensuring sustainable water availability. This protection should be based on a clear understanding of lake-wetland hydrological responses to natural and human-induced changes, which is currently lacking in many parts of the Mediterranean. The interconnected Prespa-Ohrid Lake system is a global hotspot of biodiversity and endemism. The unprecedented fall in water level (~8m) of Lake Megali Prespa threatens this system, but causes remain debated. Modelling suggests that the S Balkan will experience rainfall and runoff decreases of ~30% by 2050. However, projections revealing the potential impact of these changes on future lake level are unavailable as lake regime is not understood. A further drop in lake level may have serious consequences. The Prespa Lakes contribute ~25% of the total inflow into Lake Ohrid through underground karst channels; falling lake levels decrease this discharge. Lake Ohrid, in turn, feeds the Drim River. This entire catchment may therefore be affected by falling lake levels; its water resources are of great importance for Greece, Albania, FYROM and Montenegro (e.g. tourism, agriculture, hydro-energy, urban & industrial use). This new work proves that annual water level fluctuations of Lake Megali Prespa are predominantly related to precipitation during the first 7 months (Oct-Apr) of the hydrological year (Oct-Sep). Lake level is very sensitive to regional and

  3. Do singing-ground surveys reflect american woodcock abundance in the western Great Lakes region?

    USGS Publications Warehouse

    Matthew R. Nelson; Andersen, David E.

    2013-01-01

    The Singing-ground Survey (SGS) is the primary monitoring tool used to assess population status and trends of American woodcock (Scolopax minor). Like most broad-scale surveys, the SGS cannot be directly validated because there are no independent estimates of abundance of displaying male American woodcock at an appropriate spatial scale. Furthermore, because locations of individual SGS routes have generally remained stationary since the SGS was standardized in 1968, it is not known whether routes adequately represent the landscapes they were intended to represent. To indirectly validate the SGS, we evaluated whether 1) counts of displaying male American woodcock on SGS routes related to land-cover types known to be related to American woodcock abundance, 2) changes in counts of displaying male American woodcock through time were related to changes in land cover along SGS routes, and 3) land-cover type composition along SGS routes was similar to land-cover type composition of the surrounding landscape. In Wisconsin and Minnesota, USA, counts along SGS routes reflected known American woodcock-habitat relations. Increases in the number of woodcock heard along SGS routes over a 13-year period in Wisconsin were related to increasing amounts of early successional forest, decreasing amounts of mature forest, and increasing dispersion and interspersion of cover types. Finally, the cover types most strongly associated with American woodcock abundance were represented along SGS routes in proportion to their composition of the broader landscape. Taken together, these results suggest that in the western Great Lakes region, the SGS likely provides a reliable tool for monitoring relative abundance and population trends of breeding, male American woodcock.

  4. Global surveys of reservoirs and lakes from satellites and regional application to the Syrdarya river basin

    NASA Astrophysics Data System (ADS)

    Crétaux, Jean-François; Biancamaria, Sylvain; Arsen, Adalbert; Bergé-Nguyen, Muriel; Becker, Mélanie

    2015-01-01

    Large reservoirs along rivers regulate downstream flows to generate hydropower but may also store water for irrigation and urban sectors. Reservoir management therefore becomes critical, particularly for transboundary basins, where coordination between riparian countries is needed. Reservoir management is even more important in semiarid regions where downstream water users may be totally reliant on upstream reservoir releases. If the water resources are shared between upstream and downstream countries, potentially opposite interests arise as is the case in the Syrdarya river in Central Asia. In this case study, remote sensing data (radar altimetry and optical imagery) are used to highlight the potential of satellite data to monitor water resources: water height, areal extent and storage variations. New results from 20 years of monitoring using satellites over the Syrdarya basin are presented. The accuracy of satellite data is 0.6 km3 using a combination of MODIS data and satellite altimetry, and only 0.2 km3 with Landsat images representing 2-4% of average annual reservoir volume variations in the reservoirs in the Syrdarya basin. With future missions such as Sentinel-3A (S3A), Sentinel-3B (S3B) and surface water and ocean topography (SWOT), significant improvement is expected. The SWOT mission’s main payload (a radar interferometer in Ka band) will furthermore provide 2D maps of water height, reservoirs, lakes, rivers and floodplains, with a temporal resolution of 21 days. At the global scale, the SWOT mission will cover reservoirs with areal extents greater than 250 × 250 m with 20 cm accuracy.

  5. Growth changes of the bloater (Coregonus hoyi) of the Apostle Islands region of Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; Beil, Joseph

    1968-01-01

    Studies were based primarily on 3,097 bloaters collected in experimental gill nets and bottom trawls fished in 1958-65 in the Apostle Islands region of Lake Superior. The average size of bloaters increased considerably during the period. The percentage longer than 8.9 inches increased from 45% in 1959 to 99% in 1965. Calculated lengths were without exception higher in 1962-65 than in 1958-61. Growth in length and weight showed nearly steady improvement from 1951 to 1964. The species composition of chubs has apparently changed considerably over the past 40 years. The bloater has replaced the shortjaw cisco (C. zenithicus) as the principal species in commercial landings of chubs in Wisconsin. Annulus formation of bloaters extended from mid-May to August. Growth was slow during the spring and early summer but increased sharply in August. Age-group VI was dominant in the samples. Fluctuations in year-class strength were slight. Females outnumbered males in all age groups above III. The sex composition varied according to season of capture. Some bloaters matured at age II and all fish older than III were mature. The shortest length of mature bloaters was 6.0 inches for males and 7.0 inches for females; all fish longer than 8.4 inches were mature. Apostle Island bloaters spawn principally in February and March. The average number of eggs produced by 20 females, 8.4 to 11.7 inches long, was 6,533. Crustaceans were the most common food.

  6. Alpine Channel and Floodplain Dynamics in the Lake Tahoe Region, California

    NASA Astrophysics Data System (ADS)

    Liquori, M.; Chris, B.; Parris, A.; Heins, A.; Stofleth, J.; Wickland, M.

    2006-12-01

    Alpine floodplains provide diverse habitat components for terrestrial and aquatic species, and strongly influence bank stability and channel migration processes. They also present complex restoration challenges. Several systems in the Lake Tahoe region have been diagnosed with incised channel conditions that generate excessive mobile sediment from eroding banks, degrade riparian vegetation communities, and diminish floodplain wetland abundance and quality. Conventional efforts to restore these systems focus on reconnecting floodplains, primarily through channel or floodplain modifications designed to reestablish floodplain inundation frequency near a Q1.5 level. Recent observations along lower Squaw Creek and the Upper Truckee River suggest that human impacts and climate-induced shifts over the 20th Century appear to significantly change the processes and dynamics between channels and floodplains. Our observations highlight differences in alpine settings as compared with lowland environments. Increased rain-on-snow frequency appears to increase the importance of avulsion and channel widening processes over channel meander processes. Loss of channel sinuosity, increases in depth and changes in channel shape appear to follow rain-on-snow events. These changes affect the overall sediment transport regime, even as snowmelt duration continues to exert the primary influence over dominant discharge relationships. During floods, discontinuous, proximal deposition of coarse sediment replaces uniform, distal deposition of finer sediments, altering the structure of the channel bed and floodplain. Early snowmelt from developed hillslopes saturates floodplains even in the absence of regular flooding, potentially negating or eliminating the restorative benefit of increased flood frequency. These results suggest that effective long-term restoration strategies cannot rely on historic sinuosity patterns or simple flood frequency metrics, but must begin to understand how changes in

  7. Concentrations and potential health hazards of organochlorine pesticides in (shallow) groundwater of Taihu Lake region, China.

    PubMed

    Wu, Chunfa; Luo, Yongming; Gui, Tong; Huang, Yujuan

    2014-02-01

    A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water. PMID:24239826

  8. Geothermal potential of the Lavic Lake Region, Central Mojave Desert, California

    SciTech Connect

    Katzenstein, A.M.; Sabin, A.E.; Meade, D.M.

    1995-12-31

    Lavic Lake is a playa lake located immediately south of Pisgah Crater within lands controlled by the Marine Corps Air/Ground Combat Center in the central Mojave Desert. The Department of the Navy`s Geothermal Program Office (GPO) recently completed a second season of drilling to assess the geothermal potential at Lavic Lake. Drilling was preceded by geologic reconnaissance and a detailed gravity and ground magnetic survey. Lavic Lake is bounded to the west by the northwest-trending, right-lateral Pisgah fault and an unnamed west-trending fault to the north. The {approximately}200 ka Sunshine basalt flows and the {approximately}2-20 ka Pisgah basalt flows straddle these northwest- and west-trending faults, respectively, in the Lavic Lake area. An extensional depression related to a right bend of the Pisgah fault forms the southwest end of Lavic Lake and was the focus of the above studies. A localized 10 mgal gravity low and a coincident 500 gamma aeromagnetic low are centered within this depression. The combination of elevated temperature gradients in initial shallow holes, recent basaltic volcanism, a seismicly active fluid conduit (Pisgah fault), and hydrothermal alteration in the nearby hectorite deposit prompted the GPO to focus deeper drilling adjacent to the geophysical anomalies at the southwest end of Lavic Lake. Drilling results reveal that the geothermal potential for electrical use is negligible; however, LLTGH-5 and -6 both encountered highly fractured zones. LLTGH-6 crossed a zone of warm (110{degrees}F) fluid at 750 ft and intercepted highly fractured granitic basement at 4,175 ft.

  9. Historical seismicity of the Mont Dore volcanic province (Auvergne, France) unraveled by a regional lacustrine investigation: New insights about lake sensitivity to earthquakes

    NASA Astrophysics Data System (ADS)

    Chassiot, Léo; Chapron, Emmanuel; Di Giovanni, Christian; Lajeunesse, Patrick; Tachikawa, Kazuyo; Garcia, Marta; Bard, Edouard

    2016-06-01

    Lake sediments are relevant natural seismographs over long time scale. However, because tectonic events are not systematically recorded in lake sediments, one forthcoming challenge for paleoseismology is to better assess lake sensitivity to earthquakes. To this end, a limnogeological investigation, including hydroacoustic mapping techniques, core sampling and multi-proxy sediment analyses, has been conducted within four small volcanic lakes located in the Mont Dore province (Auvergne, France), an area with a moderate seismo-tectonic activity. Results show the existence of several gravity reworking processes in the lakes over the last millennium. Around AD 1300, the occurrence of synchronous events in lakes Pavin, Chauvet, Montcineyre and Guéry (100 km2 area) highlights an undocumented earthquake as a common trigger for slope failures in disconnected basins. At regional scale, the record of this tectonic event may have been favored by human-induced increase in sediment load (Chauvet and Montcineyre) and/or after an abrupt lake-level drop (Pavin) affecting the sediment stability. In addition, synchronous turbidites and mass-wasting deposits (MWD) recorded in lakes Pavin and Guéry provide evidence for a seismic activity during the XIXth century. Potential triggers are historical earthquakes that occurred either in the Mont Dore area or in the southern part of the Limagne fault at this time. Despite moderate seismic activity in this intraplate volcanic domain, these results highlight the role of tectonics as a major trigger in the sedimentary processes dominating these lacustrine infills. Within the diversity of studied sites, it appears that lake sensitivity to earthquakes was not constant over time. This sensitivity can be expressed as a combination of external factors, namely earthquake magnitude and lake-epicenter distance and internal factors such as lake morphology, nature of sediment, lake-level fluctuations and human-induced changes in catchment sedimentary

  10. Description of the Microsporidian Parasite, Heterosporis sutherlandae n. sp., Infecting Fish in the Great Lakes Region, USA

    PubMed Central

    Phelps, Nicholas B. D.; Mor, Sunil K.; Armién, Aníbal G.; Pelican, Katharine M.; Goyal, Sagar M.

    2015-01-01

    Heterosporosis is an increasingly important microsporidian disease worldwide, impacting wild and farmed raised fishes in both marine and freshwater environments. A previously undescribed species (Heterosporis sp.), with widespread distribution in the Great Lakes region, was the subject of this study. Three angler-caught fish were submitted to the Minnesota Veterinary Diagnostic Laboratory from 2009–2010 with lesions caused by intracellular proliferation of parasitic spores, resulting in destruction and eventual widespread necrosis of the host skeletal muscles. Mature ovoid (5.8 x 3.5μm) spores of a microsporidian parasite, consistent with the genus Heterosporis, were observed by light and electron microscopy. Molecular identification was performed using primer walking to obtain a near-complete rRNA gene sequence (~3,600 bp). A unique species of Heterosporis was identified, demonstrating less than 96% sequence identity to other published Heterosporis sp. on the basis of partial rRNA gene sequence analysis. Heterosporis sutherlandae n. sp. (formerly Heterosporis sp.) was identified in yellow perch (Perca flavescens), northern pike (Esox lucius) and walleye (Sander vitreus) from inland lakes in Minnesota and Wisconsin. Previous research suggests this species may be even more widespread in the Great Lakes region and should be reexamined using molecular techniques to better understand the distribution of this novel species. PMID:26244983

  11. Identifying risk factors of avian infectious diseases at household level in Poyang Lake region, China.

    PubMed

    Jiang, Qian; Zhou, Jieting; Jiang, Zhiben; Xu, Bing

    2014-09-01

    Poultry kept in backyard farms are susceptible to acquiring and spreading infectious diseases because of free ranging and poor biosecurity measures. Since some of these diseases are zoonoses, this is also a significant health concern to breeders and their families. Backyard farms are common in rural regions of China. However, there is lack of knowledge of backyard poultry in the country. To obtain first-hand information of backyard poultry and identify risk factors of avian infectious diseases, a cross-sectional study was carried out at household level in rural regions around Poyang Lake. A door-to-door survey was conducted to collect data on husbandry practices, trading practices of backyard farmers, and surrounding environments of backyard farms. Farms were categorized into cases and controls based on their history of poultry death. Data were collected for 137 farms, and the association with occurrence of poultry death event was explored by chi-square tests. Results showed that vaccination implementation was a protective factor (odds ratio OR=0.40, 95% confidence interval CI: 0.20-0.80, p=0.01), while contact with other backyard flocks increased risk (OR=1.72, 95% CI: 0.79-3.74, p=0.16). A concept of "farm connectivity" characterized by the density of particular land-use types in the vicinity of the farm was proposed to characterize the degree of contact between poultry in one household farm and those in other household farms. It was found that housing density in a 20-m buffer zone of the farmhouse was most significantly associated with poultry death occurrence (OR=1.08, 95% CI: 1.02-1.17, p=0.03), and was in agreement with observation of villagers. Binary logistic regression was applied to evaluate the relationship between poultry death event and density of land-use types in all buffer zones. When integrated with vaccination implementation for poultry, prediction accuracy of poultry death event reached 72.0%. Results combining questionnaire survey with

  12. The 24 July 2008 outburst flood at the western Zyndan glacier lake and recent regional changes in glacier lakes of the Teskey Ala-Too range, Tien Shan, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Narama, C.; Duishonakunov, M.; Kääb, A.; Daiyrov, M.; Abdrakhmatov, K.

    2010-04-01

    On 24 July 2008, a glacier lake outburst flood (GLOF) occurred at the western (w-) Zyndan glacier lake in the Tong District of Ysyk-Köl Oblast, Kyrgyzstan. The flood killed three people and numerous livestock, destroyed infrastructure, and devastated potato and barley crops as well as pastures. Tuurasuu village and a downstream reservoir on the Zyndan river escaped heavy damage because the main flood was diverted toward the Tong river. RTK-GPS and satellite data (Landsat 7 ETM+, ALOS/PRISM, and ALOS/AVNIR-2) reveal that the flood reduced the lake area from 0.0422 km2 to 0.0083 km2, discharging 437 000 m3 of water. This glacier lake was not present in a Landsat 7 ETM+ image taken on 26 April 2008. It formed rapidly over just two and half months from early May to the late July, when large amounts of snow and glacier melt water became trapped in a basin in the glacier terminus area, blocked by temporary closure of the drainage channel through the terminal moraine that included much dead-ice. In the same mountain region, most other glacier-lake expansions were not particularly large during the period from 1999-2008. Although events like the w-Zyndan glacier lake outburst occur infrequently in the high Central Asian mountains, such fast developing, short-lived lakes are particularly dangerous and not easy to monitor using satellite data. Appropriate measures to protect against such lake outburst hazards in this region include educating residents on glacier hazards and monitoring techniques, providing frequently updated maps of glacier lakes, and planning and monitoring land-use, including house locations.

  13. Emergence of viral hemorrhagic septicemia virus in the North American Great Lakes region is associated with low viral genetic diversity

    USGS Publications Warehouse

    Thompson, T.M.; Batts, W.N.; Faisal, M.; Bowser, P.; Casey, J.W.; Phillips, K.; Garver, K.A.; Winton, J.; Kurath, G.

    2011-01-01

    Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North Ame­rica. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this viral emergence by comparing a partial glycoprotein (G) gene sequence (669 nt) of 108 isolates collected from 2003 to 2009 from 31 species and at 37 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVb within the major VHSV genetic group IV. Among these 108 isolates, genetic diversity was low, with a maximum of 1.05% within the 669 nt region. There were 11 unique sequences, designated vcG001 to vcG011. Two dominant sequence types, vcG001 and vcG002, accounted for 90% (97 of 108) of the isolates. The vcG001 isolates were most widespread. We saw no apparent association of sequence type with host or year of isolation, but we did note a spatial pattern, in which vcG002 isolates were more prevalent in the easternmost sub-regions, including inland New York state and the St. Lawrence Seaway. Different sequence types were found among isolates from single disease outbreaks, and mixtures of types were evident within 2 isolates from ­individual fish. Overall, the genetic diversity of VHSV in the Great Lakes region was found to be extremely low, consistent with an introduction of a new virus into a geographic region with ­previously naïve host populations.

  14. Sequence analysis of the mitochondrial DNA control region of ciscoes (genus Coregonus): Taxonomic implications for the Great Lakes species flock

    USGS Publications Warehouse

    Reed, Kent M.; Dorschner, Michael O.; Todd, Thomas N.; Phillips, Ruth B.

    1998-01-01

    Sequence variation in the control region (D-loop) of the mitochondrial DNA (mtDNA) was examined to assess the genetic distinctiveness of the shortjaw cisco (Coregonus zenithicus). Individuals from within the Great Lakes Basin as well as inland lakes outside the basin were sampled. DNA fragments containing the entire D-loop were amplified by PCR from specimens ofC. zenithicus and the related species C. artedi, C. hoyi, C. kiyi, and C. clupeaformis. DNA sequence analysis revealed high similarity within and among species and shared polymorphism for length variants. Based on this analysis, the shortjaw cisco is not genetically distinct from other cisco species.

  15. Low prevalence of VHSV detected in round goby collected in offshore regions of Lake Ontario

    USGS Publications Warehouse

    Cornwell, Emily R.; Getchell, Rodman G.; Groocock, Geoffrey H.; Walsh, Maureen G.; Bowser, Paul R.

    2012-01-01

    Since the first reports of mortalities due to viral hemorrhagic septicemia virus (VHSV) type IVb in the Laurentian Great Lakes basin during 2005 (Lake St. Clair, USA and Bay of Quinte, Lake Ontario, Canada), many groups have conducted surveillance efforts for the virus, primarily in nearshore areas. The round goby (Neogobius melanostomus) has been identified as a key species to target for surveillance, because they have a very high probability of infection at a given site. Our objective in this study was to document and quantify VHSV in round gobies in offshore waters of Lake Ontario using molecular techniques. We collected 139 round gobies from depths ranging from 55 to 150 m using bottom trawls during the early spring of 2011 and detected VHSV in 4 individuals (1/26 fish at 95 m, 2/12 fish at 105 m, and 1/24 fish at 135 m). These results expand the known depth range of VHSV in the Great Lakes. They also have implications on the management of the spread of VHSV within infected bodies of water related to the mixing of populations of fish that would remain distinct in their breeding habitats, but then have the opportunity to mix in their overwintering habitats, as well as to increase overlap of predator and prey species in overwintering habitats.

  16. Unplanned roads impacts assessment in Phewa Lake watershed, Western region, Nepal

    NASA Astrophysics Data System (ADS)

    Leibundgut, Geoffroy; Sudmeier-Rieux, Karen; Devkota, Sanjaya; Jaboyedoff, Michel; Penna, Ivanna; Adhikari, Anu; Khanal, Rajendra

    2015-04-01

    This work describes current research being conducted in the Phewa Lake watershed, near Pokhara in Nepal's Siwaliks/Middle hills, a moist sub-tropical zone with the highest amount of annual rainfall in Nepal (4,500 - 5,000 mm). The watershed lithology is mainly siltstone, sandstones and intensively weathered rocks, highly prone to erosion and shallow landslides (Agrawala et al., 2003). The main purpose of this study is to focus on the impact of unplanned earthen road construction in the Phewa Lake watershed as part of land use changes over 30 years in one of Nepal's most touristic regions. Over the past three decades, the road network has expanded exponentially and a majority of rural earthen roads are often funded by communities themselves, with some government subsidies. They are usually constructed using a local bulldozer contractor with no technical or geological expertise increasing erosion processes, slope instabilities risk and impacts to settlements, forests, water sources, agriculture lands, and infrastructure. Moreover, these human-induced phenomena are being compounded by increasingly intense monsoon rains, likely due to climate change (Petley, 2010). Research methods were interdisciplinary and based on a combination of remote sensing, field observations and discussions with community members. The study compared 30 year-old aerial photos with current high resolution satellite images to correlate changes in land use with erosion and slope instabilities. Secondly, most of the watershed's roads were surveyed in order to inventory and quantify slope instabilities and soil loss events. Using a failure-characteristics grid, their main features were measured (location, size, type and extension of damage areas, etc.) and a GIS data base was created. We then estimated economic impacts of these events in terms of agriculture lands losses and road maintenance, based on field observations and discussions with affected people. Field work investigations have shown that

  17. Endocrine disruption and altered gonadal development in white perch (Morone americana) from the lower Great Lakes region.

    PubMed Central

    Kavanagh, Richard J; Balch, Gordon C; Kiparissis, Yiannis; Niimi, Arthur J; Sherry, Jim; Tinson, Cheryl; Metcalfe, Chris D

    2004-01-01

    High prevalences of gonadal intersex have been observed in wild fish populations in areas affected by domestic and industrial effluents. For this study, fish were collected in 1998 from the Cootes Paradise region of Hamilton Harbour in western Lake Ontario, Canada, to determine whether gonadal abnormalities, including intersex, were present in young of the year (YOY) fish. No gonadal abnormalities were observed in goldfish (Carassius auratus), common carp (Cyprinus carpio), gizzard shad (Dorosoma cepedianum), brown bullhead (Ictalurus ameiurus), pumpkinseed (Lepomis gibbosus), and bluegill (Lepomis macrochirus). However, intersex gonads were observed in 8 of 16 male white perch (Morone americana) examined in this survey. Subsequently, in 1999 and 2000 white perch estimated to be YOY to approximately 2 years of age were collected from Cootes Paradise and from two other sites in the lower Great Lakes region. Gonadal intersex was observed in male white perch collected from the Bay of Quinte (22-44%) and Lake St. Clair (45%), although the prevalence and the extent of the intersex condition were lower relative to the 83% prevalence in white perch collected in Cootes Paradise. Intersex was not observed in hatchery-reared white perch or in white perch collected from an uncontaminated reference site (i.e., Deal Lake) in the United States. An analysis of plasma collected in the spring of 2002 from male adult white perch in Cootes Paradise revealed high concentrations of vitellogenin, ranging from 49 to 1,711 microg/mL. These observations indicate that male white perch are exposed to estrogenic endocrine-disrupting substances that may be responsible for the induction of gonadal intersex. PMID:15175179

  18. [Algo-bacterial communities of the Kulunda steppe (Altai region, Russia) soda lakes].

    PubMed

    Samylina, O S; Sapozhnikov, F V; Gaĭnanova, O Iu; Riabova, A V; Nikitin, M A; Sorokin, D Iu

    2015-01-01

    The composition and macroscopic structure of the floating oxygenic phototrophic communities from Kulunda steppe soda lakes (Petukhovskoe sodovoe, Tanatara VI, and Gorchiny 3) was described based on the data of the 2011 and 2012 expeditions (Winogradsky Institute of Microbiology). The algo-bacterial community with a green alga Ctenocladus circinnatus as an edificator was the typical one. Filamentous Geitlerinema sp. and Nodosilinea sp. were the dominant cyanobacteria. Apart from C. circinnatus, the algological component of the community contained unicellular green algae Dunaliella viridis and cf. Chlorella minutissima, as well as diatoms (Anomeoneis sphaerophora, Brchysira brebissonii, Brachysira zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, Nitzschia communis, and Nitzschia sp.1). The latter have not been previously identified in the lakes under study. In all lakes, a considerable increase in salinity was found to result in changes in the composition and macroscopic structure of algo-bacterial communities. PMID:25916153

  19. Landscape drivers of regional variation in the relationship between total phosphorus and chlorophyll in lakes

    USGS Publications Warehouse

    Wagner, T.; Soranno, P.A.; Webster, K.E.; Cheruvelil, K.S.

    2011-01-01

    For north temperate lakes, the well-studied empirical relationship between phosphorus (as measured by total phosphorus, TP), the most commonly limiting nutrient and algal biomass (as measured by chlorophyll a, CHL) has been found to vary across a wide range of landscape settings. Variation in the parameters of these TP-CHL regressions has been attributed to such lake variables as nitrogen/phosphorus ratios, organic carbon and alkalinity, all of which are strongly related to catchment characteristics (e.g. natural land cover and human land use). Although this suggests that landscape setting can help to explain much of the variation in ecoregional TP-CHL regression parameters, few studies have attempted to quantify relationships at an ecoregional spatial scale. We tested the hypothesis that lake algal biomass and its predicted response to changes in phosphorus are related to both local-scale features (e.g. lake and catchment) and ecoregional-scale features, all of which affect the availability and transport of covarying solutes such as nitrogen, organic carbon and alkalinity. Specifically, we expected that land use and cover, acting at both local and ecoregional scales, would partially explain the spatial pattern in parameters of the TP-CHL regression. We used a multilevel modelling framework and data from 2105 inland lakes spanning 35 ecoregions in six US states to test our hypothesis and identify specific local and ecoregional features that explain spatial heterogeneity in TP-CHL relationships. We include variables such as lake depth, natural land cover (for instance, wetland cover in the catchment of lakes and in the ecoregions) and human land use (for instance, agricultural land use in the catchment of lakes and in the ecoregions). There was substantial heterogeneity in TP-CHL relationships across the 35 ecoregions. At the local scale, CHL was negatively and positively related to lake mean depth and percentage of wooded wetlands in the catchment, respectively. At

  20. ERTS-1 imagery of the Lake Champlain region: A first look

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (Principal Investigator); Henson, E. B.; Olson, J.; Wagner, W. P.

    1972-01-01

    The author has identified the following significant results. First-look analysis of RBV imagery of Lake Champlain and adjacent areas provided the following information on land and water resources: (1) location and shape of islands over 200 meters at narrowest part; (2) location of manmade structures at least 10 meters across; (3) location of shoreline; (4) identification of algal blooms and major turbidity boundary; (5) identification of lake bottom features in sandy, shallow areas; (6) identification of major lake shore wetland and floodplain wetlands; (7) location of major streams; (8) identification of ice marginal deposits of major proportions and former shorelines of Champlain Sea; (9) identification of wooded areas, open land, and built-up areas.

  1. Regional analysis of the effect of paved roads on sodium and chloride in lakes.

    PubMed

    Kelting, Daniel L; Laxson, Corey L; Yerger, Elizabeth C

    2012-05-15

    Salinization of surface water from sodium chloride (road salt) applied to paved roads is a widely recognized environmental concern in the northern hemisphere, yet practical information to improve winter road management to reduce the environmental impacts of this deicer is lacking. The purpose of our study was to provide such information by developing baseline concentrations for sodium and chloride for lakes in watersheds without paved roads, and then determining the relationship between these ions and density, type, and proximity of paved roads to shoreline. We used average summer (June-September) sodium and chloride data for 138 lakes combined in a watershed based analysis of paved road networks in the Adirondack Park of New York, U.S.A. The watersheds used in our study represented a broad range in paved road density and type, 56 of which had no paved roads. Median lake sodium and chloride concentrations in these 56 watersheds averaged 0.55 and 0.24 mg/L, respectively. In contrast, the median sodium and chloride concentrations for the 82 lakes in watersheds with paved roads were 3.60 and 7.22 mg/L, respectively. Paved road density (lane-km/km(2)) was positively correlated with sodium and chloride concentrations, but only state roads were significantly correlated with sodium and chloride while local roads were not. State road density alone explained 84 percent of the variation in both ions. We also successfully modeled the relationship between road proximity to shoreline and sodium and chloride concentrations in lakes, which allowed us to identify sections of road that contributed more to explaining the variation in sodium and chloride in lakes. This model and our approach could be used as part of larger efforts to identify environmentally sensitive areas where alternative winter road management treatments should be applied. PMID:22406283

  2. The Impact of Incongruous Lake Temperatures on Regional Climate Extremes Downscaled from the CMIP5 Archive Using the WRF Model

    EPA Science Inventory

    The impact of incongruous lake temperatures is demonstrated using the Weather Research and Forecasting (WRF) Model to downscale global climate fields. Unrealistic lake temperatures prescribed by the default WRF configuration cause obvious biases near the lakes and also affect pre...

  3. Comparison of abundances of chemical elements in mineralized and unmineralized sandstone of the Brushy Basin Member of the Morrison Formation, Smith Lake District, Grants uranium region, New Mexico

    USGS Publications Warehouse

    Pierson, C.T.; Spirakis, C.S.; Robertson, J.F.

    1983-01-01

    Statistical treatment of analytical data from the Mariano Lake and Ruby uranium deposits in the Smith Lake district, New Mexico, indicates that organic carbon, arsenic, barium, calcium, cobalt, copper, gallium, iron, lead, manganese, molybdenum, nickel, selenium, strontium, sulfur, vanadium, yttrium, and zirconium are concentrated along with uranium in primary ore. Comparison of the Smith Lake data with information from other primary deposits in the Grants uranium region and elsewhere in the Morrison Formation of the Colorado Plateau suggests that these elements, with the possible exceptions of zirconium and gallium and with the probable addition of aluminum and magnesium, are typically associated with primary, tabular uranium deposits. Chemical differences between the Ruby and Mariano Lake deposits are consistent with the interpretation that the Ruby deposit has been more affected by post-mineralization oxidizing solutions than has the Mariano Lake deposit.

  4. Geology, hydrology, and mineral resources of crystalline rock areas of the Lake Superior region, United States. Part 1

    SciTech Connect

    Harrison, W.; Edgar, D.; Van Luik, A.; Hinze, W.; Braile, L.; Kalliokoski, J.; Pfannkuch, H.; Wright, H. Jr.; Tisue, M.; Sood, M.

    1983-10-01

    This report, which includes a series of maps, is a compendium of the available information on several topics of importance in defining the geologic setting of crystalline rocks in the Lake Superior region (Minnesota, Wisconsin, and the Upper Peninsula of Michigan). Crystalline rocks are defined herein as bodies of medium; and coarse-grained igneous and high-grade metamorphic rocks. The study was undertaken to provide background information to assist in evaluating the suitability of such rocks for isolating high-level radioactive waste. Topics covered include geologic history of the region; patterns of earthquake occurrence, earthquake magnitudes and horizontal ground accelerations, crustal stress, regional fault domains, and Holocene faulting and vertical crustal movements; surface processes, anticipated climatic changes, and effects of renewed glaciation; landforms and surficial deposits; regional surface; and ground-water hydrology; and commercial potential of rock and mineral prospects of mines located within or near crystalline rock bodies. References, 117 figures, 36 tables.

  5. Hydroclimate variability and regional atmospheric circulation over the past 1,350 years reconstructed from Lake Ohau, New Zealand

    NASA Astrophysics Data System (ADS)

    Roop, H. A.; Levy, R. H.; Lorrey, A.; Vandergoes, M.; Dunbar, G. B.; Howarth, J. D.

    2014-12-01

    Comprehensive understanding of natural climate-system dynamics requires high-resolution paleoclimate records extending beyond the instrumental period. This is particularly the case for the sparsely-instrumented Southern Hemisphere mid-latitudes, where the timing and amplitude of regional and hemispheric-scale climatic events are poorly constrained. Here we present a 1,350-year record of hydroclimatic variability and regional circulation derived from an annually laminated sediment record from Lake Ohau, South Island, New Zealand (44.23°S, 169.85°E). The climate of New Zealand is influenced by climatological patterns originating in both the tropics (e.g. El-Niño-Southern Oscillation, Interdecadal Pacific Oscillation) and the Antarctic (Southern Annular Mode, SAM). Utilizing the annually resolved Lake Ohau hydroclimate record in combination with a tree-ring record of summer temperature from Oroko Swamp, New Zealand (Cook et al., 2002), we generate a circulation index for the Western South Island of New Zealand. This index utilizes the temperature and precipitation anomalies defined by the Regional Climate Regime Classification scheme for New Zealand (Kidson, 2000) to assign synoptic scale circulation patterns to 25-year intervals from 900-2000 AD. This circulation index shows significant periods of change, most notably 835 - 985 AD when northerly airflow dominated and from 1385 - 1710 AD when strong southerly airflow persisted. Comparisons with regional SAM and ENSO reconstructions show that dry, warm conditions at Lake Ohau are consistently associated with strengthened tropical teleconnections to New Zealand and a positive SAM, while cold and wet conditions are driven by increased southerly airflow and negative phase SAM. A persistent negative SAM dominates the Little Ice Age (LIA; ~1385-1710 AD) interval in the Western South Island. This same period coincides with the Northern Hemisphere LIA.

  6. Hydroclimate variability and regional atmospheric circulation over the past 1,350 years reconstructed from Lake Ohau, New Zealand

    NASA Astrophysics Data System (ADS)

    Roop, H. A.; Levy, R. H.; Lorrey, A.; Vandergoes, M.; Dunbar, G. B.; Howarth, J. D.

    2015-12-01

    Comprehensive understanding of natural climate-system dynamics requires high-resolution paleoclimate records extending beyond the instrumental period. This is particularly the case for the sparsely-instrumented Southern Hemisphere mid-latitudes, where the timing and amplitude of regional and hemispheric-scale climatic events are poorly constrained. Here we present a 1,350-year record of hydroclimatic variability and regional circulation derived from an annually laminated sediment record from Lake Ohau, South Island, New Zealand (44.23°S, 169.85°E). The climate of New Zealand is influenced by climatological patterns originating in both the tropics (e.g. El-Niño-Southern Oscillation, Interdecadal Pacific Oscillation) and the Antarctic (Southern Annular Mode, SAM). Utilizing the annually resolved Lake Ohau hydroclimate record in combination with a tree-ring record of summer temperature from Oroko Swamp, New Zealand (Cook et al., 2002), we generate a circulation index for the Western South Island of New Zealand. This index utilizes the temperature and precipitation anomalies defined by the Regional Climate Regime Classification scheme for New Zealand (Kidson, 2000) to assign synoptic scale circulation patterns to 25-year intervals from 900-2000 AD. This circulation index shows significant periods of change, most notably 835 - 985 AD when northerly airflow dominated and from 1385 - 1710 AD when strong southerly airflow persisted. Comparisons with regional SAM and ENSO reconstructions show that dry, warm conditions at Lake Ohau are consistently associated with strengthened tropical teleconnections to New Zealand and a positive SAM, while cold and wet conditions are driven by increased southerly airflow and negative phase SAM. A persistent negative SAM dominates the Little Ice Age (LIA; ~1385-1710 AD) interval in the Western South Island. This same period coincides with the Northern Hemisphere LIA.

  7. [Landscape ecological risk assessment and its spatio-temporal variations in Ebinur Lake region of inland arid area].

    PubMed

    Zhang, Yue; Zhang, Fei; Zhou, Mei; Li, Xiao-hang; Ren, Yan; Wang, Juan

    2016-01-01

    The typical region of the Ebinur Lake Basin was chosen as study area. Landsat TM/OLI images for 1998, 2011 and 2013 were obtained. In the study area, landscape was classified into six types, including cropland, woodland, grassland, water body, bare lake bed, salinized land and unutilized land. Landscape indices and ecological risk index were calculated and spatially interpolated for the whole region, which was divided into five different risk zones: extremely low, low, moderate, high and extremely high ecological risk. They were carried out for assessing the spatio-temporal changes in ecological risk for each landscape pattern. The results showed that the regional landscape patterns had experienced significant changes, and the increase in the area of croplands was the main trend in landscape evolution from 1998-2013. The main part of the regional ecosystem faced extremely high risk in 1998, high risk in 2011 and low risk in 2013. The ecological risk level of the study area was significantly decreased in the overall period, and the total area of change from high to low risk was much greater than those from low to high risk. PMID:27228614

  8. Compositional Variations of Primary Basalts in the Poison Lake Chain, Lassen Region of Northern California

    NASA Astrophysics Data System (ADS)

    Lewis, G. T.; Teasdale, R.; Wenner, J. M.

    2015-12-01

    Multiple compositional mantle domains are represented by primitive basalts of the Poison Lake chain (PLC), located east of the Lassen Volcanic Center in the southern Cascades and on the western margin of the Basin and Range. Four of the nine compositional groups of PLC basalts include primary basalt samples that represent distinct mantle compositions from which other samples are likely derived. Primitive basalts from two of the groups, the old railroad grade (bg; 102.1 +/- 11.4 ka) and the basalts of Poison Butte (bp; 105.0 +/- 6.0 ka), spatially and chronologically overlap. Both groups are primitive basalts that have phenocrysts of olivine, plagioclase and clinopyroxene. However, bg has larger, more euhedral olivine while bp has fewer, smaller, anhedral and embayed olivine phenocrysts. Compositionally, bg has higher whole-rock MgO (9.2-12.2 %) and Ni (189-238 ppm) and lower Zr (57-89 ppm) than bp (MgO = 5.3-7.8 %; Ni = 35-89 ppm; Zr = 98-153 ppm), suggesting bp has undergone more fractionation than bg. MELTS and REE models predict that the most primitive unit of bg (bg3) could have fractionated to produce the other three bg units. Similarly, MELTS and REE models suggest that four of the six units of bp can be derived by fractional crystallization from bg3. However, those models require that bg3 would need to fractionate between 40-50% in order to generate the bp compositions. Unreasonably high % fractionation suggests that the relationship between bg and bp groups is more complex than simple fractionation allows, but their similar Cr spinel compositions (bg Cr# =32.9-50.9 and bp Cr# = 44.0-56.3) suggest bg and bp are likely derived from a common mantle source. Additional petrogenetic modeling and isotope analyses will help clarify the relationship between PLC primitive basalt groups. The combination of small scale mantle heterogeneities along with detailed examination of magma processing are only recognized in the PLC with high density sampling, which may be

  9. Projected Precipitation Changes within the Great Lakes Region: A Multi-scale Analysis of Precipitation Intensity and Seasonality

    NASA Astrophysics Data System (ADS)

    Basile, S.; Steiner, A. L.; Brown, D.; Bryan, A. M.

    2014-12-01

    The Great Lakes region supports a diverse network of agriculture, transportation and tourism centered on some of the largest freshwater bodies of water in the world. Precipitation affects these sectors as concerns about precipitation timing and intensity can affect the agricultural growing season, runoff, and subsequent water quality. Here, we examine precipitation projections for mid-century (2041-2065) within the Great Lakes basin (GLB) and two sub-regions using three climate model ensembles of varying resolutions to constrain and compare associated precipitation uncertainties. These include: 1. atmosphere-ocean models from the CMIP5 global simulations with the RCP 8.5 scenario (12 members, resolution ranging from ~1 to ~3 degrees), 2. dynamically downscaled regional climate models from NARCCAP with the SRES A2 scenario (4 members at ~0.5 degree resolution (50 km)), and 3. high resolution (~0.25 degree resolution (25 km)) regional climate model simulations with the RCP 8.5 scenario (RegCM (hereafter RCM3(HiRes)), 2 members). For the entire GLB, all three ensembles captured the intensity of historical events well, but with a bias in the high intensity precipitation events as compared to observed intensity, with fewer overprediction events by the NARCCAP and RCM3(HiRes) ensembles. Daily probability density functions from three model ensembles reveal consistent increases in high precipitation event probabilities for all seasons, even after accounting for wet model biases during the observation period (1980-1999). Comparing all three ensembles to the historical period for the GLB, both CMIP5 and NARCCAP ensembles capture the annual seasonal cycle with a wet bias in the winter and spring, while the RCM3(HiRes) ensemble shows a dry bias for all seasons except winter. For the Lake Michigan and Western Lake Erie basin sub-regions, the spring and winter biases remain present across ensembles, however the RCM3(HiRes) summer dry bias is reduced. Overall, the three climate

  10. Watershed Influences on Nearshore Waters Across the Entire US Great Lakes Coastal Region

    EPA Science Inventory

    We have combined three elements of observation to enable a comprehensive characterization of the Great Lakes nearshore that links nearshore conditions with their adjacent coastal watersheds. The three elements are: 1) a shore-parallel, high-resolution survey of the nearshore usin...

  11. The Fossil Fauna of the Islands Region of Western Lake Erie.

    ERIC Educational Resources Information Center

    Bowe, Lulu M., Comp.

    The islands of western Lake Erie are rock-bound isles that abound in rocky outcrops and quarries. The rocks of these islands are of two distinct types, Silurian dolomites and Devonian limestones. The dolomites, exposed in the Bass Islands and Sister Islands are virtually devoid of fossils. Conversely, the limestones of Johnson Island, Marblehead,…

  12. REGIONAL LAKE TROPHIC PATTERNS IN THE NORTHEASTERN UNITED STATES: THREE APPROACHES

    EPA Science Inventory

    During the summers of 1991-1994, the Environmental Monitoring and Assessment Progam (EMAP) conducted variable probability sampling on 344 lakes throughout the northeastern United States. Trophic state data were analyzed for the Northeast as a whole and for each of its three major...

  13. The Dynamics of American Indian Diplomacy in the Great Lakes Region

    ERIC Educational Resources Information Center

    Ramirez-Shkwegnaabi, Benjamin

    2003-01-01

    Throughout the nineteenth century Anishinaabeg leaders from the Great Lakes met in treaty councils with U.S. commissioners. Trained for years as astute listeners and eloquent speakers, these diplomats put their skills to the test as they negotiated with their non-Indian counterparts, whose primary responsibility was to serve the interests of the…

  14. Seasonal radon measurements in Darbandikhan Lake water resources at Kurdistan region-northeastern of Iraq

    NASA Astrophysics Data System (ADS)

    Jafir, Adeeb Omer; Ahmad, Ali Hassan; Saridan, Wan Muhamad

    2016-03-01

    A total of 164 water samples were collected from Darbandikhan Lake with their different resources (spring, stream, and lake) during the four seasons, and the measurements were carried out using the electronic RAD 7 detector. For spring water the average radon concentration for spring, summer, autumn and summer were found to be 8.21 Bq/1, 8.94 Bq/1, 7.422 Bq/1, and 8.06 Bq/1, respectively, while for lake and streams the average values were found to be 0.43 Bq/1, 0.877 Bq/1, 0.727 Bq/1, 0.575 Bq/1 respectively. The radon concentration level was higher in summer and lower in spring, and only two samples from spring water have radon concentrations more than 11.1 Bq/1 recommended by the EPA. Total annual effective dose due to ingestion and inhalation has been estimated, the mean annual effective dose during the whole year for spring water was 0.022 mSv/y while for lake with streams was 0.00157 mSv/y. The determined mean annual effective dose in water was lower than the 0.1 mSv/y recommended by WHO. Some physicochemical parameters were measured and no correlation was found between them and radon concentration except for the conductivity of the spring drinking water which reveals a strong correlation for the four seasons.

  15. Impact of immigrant pastoral herds to fringing wetlands of lake Victoria in Magu district Mwanza region, Tanzania

    NASA Astrophysics Data System (ADS)

    Hongo, H.; Masikini, M.

    The assessment of impacts of pastoral herds to the fringing wetlands of Lake Victoria in Magu district in Mwanza region was carried out in 1999/2000. Lamadi village located along Speke Gulf of Lake Victoria was chosen. The main farming systems in the area are agriculture, agro-pastoralism, and pastoralism. The wetlands are heavily used for livestock grazing during the dry season. Since 1990s the area has been experiencing a high influx of immigrant pastoral herds from drought prone districts. The increasing livestock numbers have led into serious degradation of wetlands. The type of damages includes: soil erosion, loss of vegetation cover and deforestation. This lead to pollution of Lake Victoria along the Speke gulf in particular as the wetlands was buffering a lot of pollutants from the catchments. The range condition at Lamadi was rated fair. The carrying capacity of rangelands was estimated at 3.57-6.75 ha/LU and the wetlands were seriously degraded causing heavy soil erosion and environmental pollution during rainy season. It was recommended to raise people’s awareness on conservation of environment and mobilise communities to take responsibility on management of the environmental resources.

  16. Accounting for inter-annual and seasonal variability in regionalization of hydrologic response in the Great Lakes basin

    NASA Astrophysics Data System (ADS)

    Kult, J. M.; Fry, L. M.; Gronewold, A. D.

    2012-12-01

    Methods for predicting streamflow in areas with limited or nonexistent measures of hydrologic response typically invoke the concept of regionalization, whereby knowledge pertaining to gauged catchments is transferred to ungauged catchments. In this study, we identify watershed physical characteristics acting as primary drivers of hydrologic response throughout the US portion of the Great Lakes basin. Relationships between watershed physical characteristics and hydrologic response are generated from 166 catchments spanning a variety of climate, soil, land cover, and land form regimes through regression tree analysis, leading to a grouping of watersheds exhibiting similar hydrologic response characteristics. These groupings are then used to predict response in ungauged watersheds in an uncertainty framework. Results from this method are assessed alongside one historical regionalization approach which, while simple, has served as a cornerstone of Great Lakes regional hydrologic research for several decades. Our approach expands upon previous research by considering multiple temporal characterizations of hydrologic response. Due to the substantial inter-annual and seasonal variability in hydrologic response observed over the Great Lakes basin, results from the regression tree analysis differ considerably depending on the level of temporal aggregation used to define the response. Specifically, higher levels of temporal aggregation for the response metric (for example, indices derived from long-term means of climate and streamflow observations) lead to improved watershed groupings with lower within-group variance. However, this perceived improvement in model skill occurs at the cost of understated uncertainty when applying the regression to time series simulations or as a basis for model calibration. In such cases, our results indicate that predictions based on long-term characterizations of hydrologic response can produce misleading conclusions when applied at shorter

  17. Flame retardants in eggs of American kestrels and European starlings from southern Lake Ontario region (North America).

    PubMed

    Chen, Da; Letcher, Robert J; Martin, Pamela

    2012-11-01

    While a number of studies have extensively investigated flame retardant (FR) contamination in aquatic ecosystems from the Laurentian Great Lakes basin, there remains a dearth of information for terrestrial ecosystems. In the current study, American kestrels (Falco sparverius) (AMKE) and European starlings (Sturnus vulgaris) (EUST) that are terrestrial ecosystem consumers, and from the southern Lake Ontario regions, were investigated as potential terrestrial bio-monitoring species. Egg homogenates were screened for sixteen PBDE congeners and nineteen non-PBDE FRs of established or emerging environmental importance. PBDE congeners dominated the FR burdens in eggs of AMKE and EUST, with total concentrations ranging from 3.4 to 39.8 (median: 13.5) and 1.5 to 117 (median: 4.9) ng g(-1) wet weight (ww), respectively. Although the production and application of the Firemaster FF-1 (a commercial hexabromobiphenyl PBB mixture) has been discontinued for over four decades, its major component, 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), was still frequently detected in AMKE and EUST eggs. Two isomers of the chlorinated FR Dechlorane plus (DP) were mostly detected in eggs collected from Niagara-on-the-Lake in the western portion of Lake Ontario, approximately 15 km from the only North American DP manufacturing site, clearly reflecting point source influences. FR comparisons in eggs from AMKE, EUST and Great Lakes herring gulls revealed species-specific contamination burdens and PBDE congener profiles, likely due to influences from trophic levels and PBDE congener-specific bioaccumulation and biomagnification capacities in terrestrial versus aquatic food chains. Insectivorous birds (e.g. great tit) and relatives of AMKE have also been used as bio-monitoring tools in European and Asian regions, allowing investigation of spatial distribution patterns on a more international scale. AMKE and EUST have also been used as model species for laboratory evaluation of FR toxic effects in

  18. Problems with the claim of ecotype and taxon status of the wolf in the Great Lakes region

    USGS Publications Warehouse

    Cronin, Matthew A.; Mech, L. David

    2009-01-01

    Koblmuller et al. (2009) analysed molecular genetic data of the wolf in the Great Lakes (GL) region of the USA and concluded that the animal was a unique ecotype of grey wolf and that genetic data supported the population as a discrete wolf taxon. However, some of the literature that the researchers used to support their position actually did not, and additional confusion arises from indefinite use of terminology. Herein, we discuss the problems with designation of a wolf population as a taxon or ecotype without proper definition and assessment of criteria.

  19. Phylogenetic analysis of Newcastle disease viruses isolated from wild birds in the Poyang Lake region of China

    PubMed Central

    FAN, Shengtao; WANG, Tiecheng; GAO, Xiaolong; YING, Ying; LI, Xue; LI, Yongcheng; LI, Yuanguo; MA, Jinzhu; SUN, Heting; CHU, Dong; XU, Yu; YANG, Songtao; LI, Qihan; GAO, Yuwei; XIA, Xianzhu

    2015-01-01

    Newcastle disease virus (NDV) causes a highly contagious viral disease in poultry and wild birds, and it can cause significant economic loss worldwide. Eight viral strains were isolated by inoculating embryonated chicken eggs from the Poyang Lake region of China with swab samples. All eight of the NDV isolates were identified as class I genotype 3 strains, but they diverged notablely from class II viruses. Further analysis revealed that all eight NDV isolates were lentogenic strains containing the 112ERQER↓L117 motif at the F protein cleavage site. The strains were highly identical and were more species specific (chicken and waterfowl) than site specific (Nanchang and Duchang regions). The close phylogenetic proximity of these isolates indicates that viral transmission may happen between poultry and wild birds. Our study demonstrates that lentogenic class I NDVs exist in clinically healthy wild waterfowl and poultry within the Poyang Lake region. Active surveillance of these viruses to determine their evolution and origin is one of the most realistic strategies for preventing and controlling NDV outbreaks. PMID:25843743

  20. Phylogenetic analysis of Newcastle disease viruses isolated from wild birds in the Poyang Lake region of China.

    PubMed

    Fan, Shengtao; Wang, Tiecheng; Gao, Xiaolong; Ying, Ying; Li, Xue; Li, Yongcheng; Li, Yuanguo; Ma, Jinzhu; Sun, Heting; Chu, Dong; Xu, Yu; Yang, Songtao; Li, Qihan; Gao, Yuwei; Xia, Xianzhu

    2015-09-01

    Newcastle disease virus (NDV) causes a highly contagious viral disease in poultry and wild birds, and it can cause significant economic loss worldwide. Eight viral strains were isolated by inoculating embryonated chicken eggs from the Poyang Lake region of China with swab samples. All eight of the NDV isolates were identified as class I genotype 3 strains, but they diverged notablely from class II viruses. Further analysis revealed that all eight NDV isolates were lentogenic strains containing the (112)ERQER↓L(117) motif at the F protein cleavage site. The strains were highly identical and were more species specific (chicken and waterfowl) than site specific (Nanchang and Duchang regions). The close phylogenetic proximity of these isolates indicates that viral transmission may happen between poultry and wild birds. Our study demonstrates that lentogenic class I NDVs exist in clinically healthy wild waterfowl and poultry within the Poyang Lake region. Active surveillance of these viruses to determine their evolution and origin is one of the most realistic strategies for preventing and controlling NDV outbreaks. PMID:25843743

  1. Carbon isotope systematics and CO2 sources in The Geysers-Clear Lake region, northern California, USA

    USGS Publications Warehouse

    Bergfeld, D.; Goff, F.; Janik, C.J.

    2001-01-01

    Carbon isotope analyses of calcite veins, organic carbon, CO2 and CH4 from 96 rock and 46 gas samples show that metamorphic calcite veins and disseminated, organically-derived carbon from Franciscan Complex and Great Valley Sequence rocks have provided a primary carbon source for geothermal fluids during past and present hydrothermal activity across The Geysers-Clear Lake region. The stable isotope compositions of calcite veins vary widely on a regional scale, but overall they document the presence of 13C-poor fluids in early subduction-related vein-precipitating events. ??13C values of calcite veins from the SB-15-D corehole within The Geysers steam field indicate that carbon-bearing fluids in the recent geothermal system have caused the original diverse ??13C values of the veins to be reset. Across The Geysers-Clear Lake region the carbon isotope composition of CO2 gas associated with individual geothermal reservoirs shows a general increasing trend in ??13C values from west to east. In contrast, ??13C values of CH4 do not exhibit any spatial trends. The results from this study indicate that regional variations in ??13C-CO2 values result from differences in the underlying lithologies. Regional CO2 contains significant amounts of carbon related to degradation of organic carbon and dissolution of calcite veins and is not related to equilibrium reactions involving CH4. CO2 from degassing of underlying magma chambers is not recognizable in this region. Published by Elsevier Science Ltd on behalf of CNR.

  2. CYPRINID DISTRIBUTIONS IN NORTHEAST U.S.A. LAKES: EVIDENCE OF REGIONAL-SCALE MINNOW BIODIVERSITY LOSSES

    EPA Science Inventory

    Fish assemblages were sampled in 195 randomly selected lakes in the northeastern United States during the summers of 1991-1994. Most lakes in northern Maine had three to seven minnow species, constituting 40-80% of species in each lake. Lakes in New Jersey, southern New York, and...

  3. Compilation of Regional Ground-Water Divides for Principal Aquifers Corresponding to the Great Lakes Basin, United States

    USGS Publications Warehouse

    Sheets, R.A.; Simonson, L.A.

    2006-01-01

    A compilation of regional ground-water divides for the five principal aquifers corresponding to the Great Lakes Basin within the United States is presented. The principal aquifers (or aquifer systems) are the Cambrian-Ordovician aquifer system, Silurian-Devonian aquifers, Mississippian aquifers, Pennsylvanian aquifers, and the surficial aquifer system. The regional ground-water divides mark the boundary between ground-water flow that discharges to the Great Lakes or their tributaries and ground-water flow that discharges to other major surface-water bodies, such as the Mississippi River. Multicounty to multistate (regional) hydrologic studies of the five principal aquifers were reviewed to determine whether adequate data, such as potentiometric surfaces or ground-water divides, were available from which ground-water flow directions or ground-water-divide locations could be derived. Examination of regional studies indicate that the regional ground-water divides for the Cambrian-Ordovician aquifer system and Silurian-Devonian aquifers have changed over time and differ from the surface-water divides in some areas. These differences can be attributed to either pumping or natural processes. The limited information on the shallow Mississippian and Pennsylvanian bedrock aquifers indicate that these aquifers and the surficial aquifer system act as one hydrostratigraphic unit and that downdip flow is insignificant. Generally, in the Mississippian and Pennsylvanian aquifers, regional ground-water divides are similar to regional surface-water divides. Previous studies of the regional ground-water divide of the surficial aquifer system depict the regional ground-water divide as generally following the regional surface-water divide. Because studies commonly focus on areas where ground-water use from an aquifer system is concentrated, the regional ground-water divides are not known in large, unstudied parts of some of these aquifer systems. A composite ground-water divide for

  4. Dynamics of Cholera Outbreaks in Great Lakes Region of Africa, 1978–2008

    PubMed Central

    Nkoko, Didier Bompangue; Giraudoux, Patrick; Plisnier, Pierre-Denis; Tinda, Annie Mutombo; Piarroux, Martine; Sudre, Bertrand; Horion, Stephanie; Tamfum, Jean-Jacques Muyembe; Ilunga, Benoît Kebela

    2011-01-01

    Cholera outbreaks have occurred in Burundi, Rwanda, Democratic Republic of Congo, Tanzania, Uganda, and Kenya almost every year since 1977–1978, when the disease emerged in these countries. We used a multiscale, geographic information system–based approach to assess the link between cholera outbreaks, climate, and environmental variables. We performed time-series analyses and field investigations in the main affected areas. Results showed that cholera greatly increased during El Niño warm events (abnormally warm El Niños) but decreased or remained stable between these events. Most epidemics occurred in a few hotspots in lakeside areas, where the weekly incidence of cholera varied by season, rainfall, fluctuations of plankton, and fishing activities. During lull periods, persistence of cholera was explained by outbreak dynamics, which suggested a metapopulation pattern, and by endemic foci around the lakes. These links between cholera outbreaks, climate, and lake environments need additional, multidisciplinary study. PMID:22099090

  5. Diel diet composition and feeding activity of round goby in the nearshore region of Lake Ontario

    USGS Publications Warehouse

    Johnson, J.H.; McKenna, J.E., Jr.; Nack, C.C.; Chalupnicki, M.A.

    2008-01-01

    Expansion of the invasive round goby Apollonia melanostoma (=Neogobius melanostomus) throughout the Great Lakes drainage has created considerable concern among fisheries management agencies. These concerns have led to several studies on the biology and impact of the goby in the basin. However, little information exists on diel patterns in food consumption of the round goby. We examined the diets of 300 round gobies collected during crepuscular, diurnal, and nocturnal periods in Lake Ontario. There was little variation in the diel diet composition of the goby, as chironomid larvae were the major prey consumed during each period. Feeding intensity of the round goby was significantly (P<0.05) greater at night than during crepuscular or diurnal periods.

  6. MULTISCALE MODELING OF AIR FLOW IN SALT LAKE CITY AND THE SURROUNDING REGION

    SciTech Connect

    M. BROWN; ET AL

    2001-01-01

    A general overview is given of a modeling effort to simulate the fate and transport of a tracer within the downtown core of Salt Lake City and beyond into the Salt Lake Basin. The problem crosses three significant scales where different physics are predominant: atmospheric mesoscale, city scale, and building scale. Three different computational fluid dynamics models were used, each with strengths at particular spatial and temporal scales. We show preliminary results and discuss what we believe to be the relevant phenomenon one must model as one crosses from atmospheric scale to engineering scale flow problems. We also describe our model validation efforts, including wind-tunnel and tow-tank experiments and a recently completed urban field experiment.

  7. Superfund Record of Decision (EPA Region 4): BMI-Textron Site, Lake Park, FL, August 1994

    SciTech Connect

    Not Available

    1994-09-01

    This decision document presents the selected remedial action for the Basic Microelectronic, Incorporated (BMI)-Textron Site (BMI-Textron Site or the Site), in Lake Park, Florida. This remedy addresses the contaminated principal threat of ground water at the Site. This remedy addresses the principal threat remaining at the Site, by using existing institutional controls, and monitoring ground water contaminated with arsenic, cyanide, sodium and fluoride.

  8. Cholera in the Lake Kivu region (DRC): Integrating remote sensing and spatially explicit epidemiological modeling

    NASA Astrophysics Data System (ADS)

    Finger, Flavio; Knox, Allyn; Bertuzzo, Enrico; Mari, Lorenzo; Bompangue, Didier; Gatto, Marino; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2014-07-01

    Mathematical models of cholera dynamics can not only help in identifying environmental drivers and processes that influence disease transmission, but may also represent valuable tools for the prediction of the epidemiological patterns in time and space as well as for the allocation of health care resources. Cholera outbreaks have been reported in the Democratic Republic of the Congo since the 1970s. They have been ravaging the shore of Lake Kivu in the east of the country repeatedly during the last decades. Here we employ a spatially explicit, inhomogeneous Markov chain model to describe cholera incidence in eight health zones on the shore of the lake. Remotely sensed data sets of chlorophyll a concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers in addition to baseline seasonality. The effect of human mobility is also modelled mechanistically. We test several models on a multiyear data set of reported cholera cases. The best fourteen models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via proper cross validation. Among these, the one accounting for seasonality, El Niño Southern Oscillation, precipitation and human mobility outperforms the others in cross validation. Some drivers (such as human mobility and rainfall) are retained only by a few models, possibly indicating that the mechanisms through which they influence cholera dynamics in the area will have to be investigated further.

  9. Gold mining impact on riverine heavy metal transport in a sparsely monitored region: the upper Lake Baikal Basin case.

    PubMed

    Thorslund, Josefin; Jarsjö, Jerker; Chalov, Sergey R; Belozerova, Ekaterina V

    2012-10-26

    Mining and ore excavation can cause the acidification and heavy metal pollution of downstream water systems. It can be difficult to assess the load contributions from individual mining areas, which is commonly required for environmental impact assessments. In the current study, we quantified the net impact of the unmonitored mining activities in the Zaamar Goldfield (Mongolia) on heavy metal transport in the downstream Tuul River-Selenga River-Lake Baikal water systems. We also noted that the Zaamar site shares the conditions of limited monitoring with many rapidly developing regions of the world. The heavy metal concentrations and flow data were obtained from historical measurement campaigns, long-term monitoring, and a novel field campaign. The results indicate that natural mass flows of heavy metals in dissolved form increased by an order of magnitude because of mining. Prevailing alkaline conditions in the vicinity of Zaamar can limit the dissolution, maintaining the on-site concentrations below health-risk based guideline values. However, suspended river concentrations are much higher than the dissolved concentrations. The placer gold mining at the Zaamar site has increased the total riverine mass flows of Al, As, Cu, Fe, Mn, Pb and Zn by 44.300, 30.1, 65.7, 47.800, 1.480, 76.0 and 65.0 tonnes per year respectively. We suggest that local to regional transformation and enrichment processes in combination with suspended sediment transport from numerous existing upstream mining areas contribute to high concentrations of dissolved heavy metals in downstream parts of the Selenga River, including its delta area at Lake Baikal. Furthermore, single hydrological events can increase the suspended load concentrations by at least one order of magnitude. Overall, the Selenga River Basin, which drains into Lake Baikal, should be recognised as one of the world's most impacted areas with regard to heavy metal loads, and it contributes to 1% and 3% of the world flux of

  10. Using Peatland Archives to Assess Climate Forcing of Holocene Vegetational Changes: Case Studies From the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Jackson, S. T.; Booth, R. K.; Andersen, J.; Hotchkiss, S.; Huang, Y.; Lesser, M.; Minckley, T.; Nichols, J.; Pendall, E.; Reeves, K.; Taylor, M.

    2006-12-01

    A dilemma has long confronted paleoecologists: pollen data are required to assess past vegetational changes, and at the same time pollen data serve as a primary source of paleoclimate inference. Paleoecologists have had to use the same data sets to infer past climate changes and the ecological responses to those changes. The emergence of independent paleoclimate proxies and archives is providing relief from this dilemma. Peatland archives are especially effective at providing independent paleoclimatic records, owing to their sensitivity to climate variation, their subcentennial to subdecadal temporal precision, and the multiplicity of available proxies. Pollen records can be obtained from the same stratigraphic levels as paleoclimate proxies, and peatland records can also be compared with lake-based pollen and macrofossil records at regional scales. Peatland records of mid- to late Holocene climate change and variability, together with pollen and macrofossil records from peatlands and lakes in the Great Lakes region of North America, resolve some long-standing questions and controversies concerning the causation of vegetational changes in the region. We present three case studies where peatlands have played a pivotal role. 1. Hemlock populations plummeted across eastern North America 5400 yr BP. The extent, rapidity, and synchrony of the event suggested that it resulted from a widespread pathogen outbreak, similar to the early 20th Century chestnut blight in the same region. However, some have argued for climate as a primary mechanism. Paleohydrological records from a kettle bog in northeastern Lower Michigan indicate an abrupt decline in water-table depth 5400 yr BP that persisted for the next 2500 years, coincident with the hemlock decline. Pathogens may have played a proximal role, but an abrupt climate shift was the ultimate driver of the hemlock decline. 2. Holocene expansions of yellow birch and beech in their northwestern ranges were episodic, alternating

  11. Geochemical Differences between two adjacent streams in the Tenaya Lake region of Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Antweiler, R.; Andrews, E. D.

    2010-12-01

    Tenaya and Murphy Creeks are two small, intermittent streams with drainage basins adjacent to each other in the Tenaya Lake region of Yosemite National Park. Tenaya Creek has a drainage basin area of 3.49 km2 ranging in elevation from 2491 to 3012 m; Murphy Creek has a drainage basin size of 7.07 km2 ranging in elevation from 2485 to 2990 m. Both basins are underlain by the Half Dome and Cathedral Peak Granodiorites (Bateman et al, 1983), with chemical compositions that are practically indistinguishable (Bateman et al, 1988). Both streams derive all of their water from snowmelt and rainfall, normally going dry by early August each year. Tenaya Creek flows primarily south-southwest, whereas Murphy Creek predominantly flows south. For nearly all of Tenaya Creek’s length it is bordered by the Tioga Pass Road, the only highway in Yosemite National Park which crosses the Sierras; on the other hand, all of Murphy Creek (except its mouth) is wilderness. During the summers of 2009 and 2010, both creeks were sampled along most of their lengths for major and trace elements. In addition, both streams have been sampled near their mouths periodically during the spring and summer (until they go dry) since 2007. Water discharge has been continuously monitored during this time. Because these streams derive all of their water from snowmelt and rainfall, the water chemistry of each must originate from atmospheric deposition, weathering of the bedrock and/or human or animal inputs. These factors, along with the similarity of the geology, topography and basin orientation, suggest that the water chemistries of the creeks should be similar. Instead, while measured sulfate concentrations in Tenaya and Murphy Creeks are similar in their upper reaches, Tenaya Creek sulfate values are almost double in the lower reaches. No other major or trace element showed a similar pattern, although sodium, potassium, calcium and rubidium showed modest increases. Other concentration differences between

  12. The Hardwood Gneiss: Evidence for high P-T Archean metamorphism in the southern province of the Lake Superior region

    SciTech Connect

    Peterson, J.W. ); Geiger, C.A. )

    1990-03-01

    The Hardwood Gneiss is an areally small unit of Precambrian granulite-grade rocks exposed in the Archean gneiss terrane of the southern Lake Superior region. The rocks are located in the southwestern portion of the Upper Peninsula of Michigan and consist of a structurally conformable package of quartzitic, metapelitic, amphibolitic, and metabasic units. Three texturally distinct garnet types are present in the metabasites and are interpreted to represent two metamorphic events. Geothermobarometry indicates conditions of {approximately}8.2-11.6 kbar and {approximately}770C for M1, and conditions of {approximately}6.0-10.1 kbar and {approximately}610-740C for M2. It is proposed that M1 was Archean and contemporaneous with a high-grade metamorphic event recorded in the Minnesota River Valley. The M2 event was probably Early Proterozoic and pre-Penokean, with metamorphic conditions more intense than those generally ascribed to the Penokean Orogeny in Michigan, but similar to the conditions reported for the Kapuskasing zone of Ontario. The high paleopressures and temperatures of the M1 event make the Hardwood Gneiss distinct from any rocks previously described in the southern Lake Superior region, and suggest intense tectonic activity during the Archean.

  13. Midcontinent rift volcanism in the Lake Superior region: Sr, Nd, and Pb isotopic evidence for a mantle plume origin

    USGS Publications Warehouse

    Nicholson, S.W.; Shirey, S.B.

    1990-01-01

    Between 1091 and 1098 Ma, most of a 15- to 20-km thickness of dominantly tholeiitic basalt erupted in the Midcontinent Rift System of the Lake Superior region, North America. The Portage Lake Volcanics in Michigan, which are the younget MRS flood basalts, fall into distinctly high- and low-TiO2 types having different liquid lines of descent. Incompatible trace elements in both types of tholeiites are enriched compared to depleted or primitive mantle and both basalt types are isotopically indistinguishable. The isotopic enrichment of the MRS source compared to depleted mantle is striking and must have occurred at least 700 m.y. before 1100 Ma. There are two likely sources for such magmatism: subcontinental lithospheric mantle enriched during the early Proterozoic or enriched mantle derived from an upwelling plume. Decompression melting of an upwelling enriched mantle plume in a region of lithosphere thinned by extension could have successfully generated the enormous volume (850 ?? 103 km3) of relatively homogeneous magma in a restricted time interval. -from Authors

  14. Schistosomiasis Research in the Dongting Lake Region and Its Impact on Local and National Treatment and Control in China

    PubMed Central

    McManus, Donald P.; Gray, Darren J.; Ross, Allen G.; Williams, Gail M.; He, Hong-Bin; Li, Yue-Sheng

    2011-01-01

    Schistosomiasis is a chronic and debilitating parasitic disease that has often been neglected because it is a disease of poverty, affecting poor rural communities in the developing world. This is not the case in the People's Republic of China (PRC), where the disease, caused by Schistosoma japonicum, has long captured the attention of the Chinese authorities who have, over the past 50–60 years, undertaken remarkably successful control programs that have substantially reduced the schistosomiasis disease burden. The Dongting Lake region in Hunan province is one of the major schistosome-endemic areas in the PRC due to its vast marshland habitats for the Oncomelania snail intermediate hosts of S. japonicum. Along with social, demographic, and other environmental factors, the recent completion and closure of the Three Gorges dam will most likely increase the range of these snail habitats, with the potential for re-emergence of schistosomiasis and increased transmission in Hunan and other schistosome-endemic provinces being a particular concern. In this paper, we review the history and the current status of schistosomiasis control in the Dongting Lake region. We explore the epidemiological factors contributing to S. japonicum transmission there, and summarise some of the key research findings from studies undertaken on schistosomiasis in Hunan province over the past 10 years. The impact of this research on current and future approaches for sustainable integrated control of schistosomiasis in this and other endemic areas in the PRC is emphasised. PMID:21912706

  15. Historical trace metal accumulation in the sediments of an urbanized region of the Lake Champlain watershed, Burlington, Vermont

    USGS Publications Warehouse

    Mecray, E.L.; King, J.W.; Appleby, P.G.; Hunt, A.S.

    2001-01-01

    This study documents the history of pollution inputs in the Burlington region of Lake Champlain, Vermont using measurements of anthropogenic metals (Cu, Zn, Cr, Pb, Cd, and Ag) in four age-dated sediment cores. Sediments record a history of contamination in a region and can be used to assess the changing threat to biota over time and to evaluate the effectiveness of discharge regulations on anthropogenic inputs. Grain size, magnetic susceptibility, radiometric dating and pollen stratigraphy were combined with trace metal data to provide an assessment of the history of contamination over the last 350 yr in the Burlington region of Lake Champlain. Magnetic susceptibility was initially used to identify land-use history for each site because it is a proxy indicator of soil erosion. Historical trends in metal inputs in the Burlington region from the seventeenth through the twentieth centuries are reflected in downcore variations in metal concentrations and accumulation rates. Metal concentrations increase above background values in the early to mid nineteenth century. The metal input rate to the sediments increases around 1920 and maximum concentrations and accumulation rates are observed in the late 1960s. Decreases in concentration and accumulation rate between 1970 and the present are observed, for most metals. The observed trends are primarily a function of variations in anthropogenic inputs and not variations in sediment grain size. Grain size data were used to remove texture variations from the metal profiles and results show trends in the anthropogenic metal signals remain. Radiometric dating and pollen stratigraphy provide well-constrained dates for the sediments thereby allowing the metal profiles to be interpreted in terms of land-use history.This study documents the history of pollution inputs in the Burlington region of Lake Champlain, Vermont using measurements of anthropogenic metals (Cu, Zn, Cr, Pb, Cd, and Ag) in four age-dated sediment cores. Sediments

  16. Immune factors and fatty acid composition in human milk from river/lake, coastal and inland regions of China.

    PubMed

    Urwin, Heidi J; Zhang, Jian; Gao, Yixiong; Wang, Chunrong; Li, Lixiang; Song, Pengkun; Man, Qingqing; Meng, Liping; Frøyland, Livar; Miles, Elizabeth A; Calder, Philip C; Yaqoob, Parveen

    2013-06-01

    Breast milk fatty acid composition may be affected by the maternal diet during gestation and lactation. The influence of dietary and breastmilk fatty acids on breast milk immune factors is poorly defined. We determined the fatty acid composition and immune factor concentrations of breast milk from women residing in river/lake, coastal and inland regions of China, which differ in their consumption of lean fish and oily fish. Breast milk samples were collected on days 3–5 (colostrum), 14 and 28 post-partum (PP) and analysed for soluble CD14 (sCD14), transforming growth factor (TGF)-b1, TGF-b2, secretory IgA (sIgA) and fatty acids. The fatty acid composition of breast milk differed between the regions and with time PP. The concentrations of all four immune factors in breast milk decreased over time, with sCD14, sIgA and TGF-b1 being highest in the colostrum in the river and lake region. Breast milk DHA and arachidonic acid (AA) were positively associated, and g-linolenic acid and EPA negatively associated, with the concentrations of each of the four immune factors. In conclusion, breast milk fatty acids and immune factors differ between the regions in China characterised by different patterns of fish consumption and change during the course of lactation. A higher breast milk DHA and AA concentration is associated with higher concentrations of immune factors in breast milk, suggesting a role for these fatty acids in promoting gastrointestinal and immune maturation of the infant. PMID:23148871

  17. Factors related to northern goshawk landscape use in the western Great Lakes region

    USGS Publications Warehouse

    Bruggeman, Jason E.; Andersen, David E.; Woodford, James E.

    2014-01-01

    Northern Goshawks (Accipiter gentilis) are a species of special conservation concern in the western Great Lakes bioregion and elsewhere in North America, and exhibit landscape-scale spatial use patterns. However, little information exists about Northern Goshawk habitat relations at broad spatial extents, as most existing published information comes from a few locations of relatively small spatial extent and, in some cases, short durations. We used an information-theoretic approach to evaluate competing hypotheses regarding factors (forest canopy cover, successional stage, and heights of the canopy top and base) related to odds of Northern Goshawk landscape use throughout the western Great Lakes bioregion based on an occupancy survey completed in 2008 (Bruggeman et al. 2011). We also combined these data with historical data of Northern Goshawk nest locations in the bioregion from 1979–2006 to evaluate the same competing hypotheses to elucidate long-term trends in use. The odds of Northern Goshawk use in 2008, and from 1979–2008, were positively correlated with average percent canopy cover. In the best-approximating models developed using 1979–2008 data, the odds of landscape use were positively correlated with the percentages of the landscape having canopy heights between 10 m and 25 m, and 25 m and 50 m, and the amount of variability in canopy base height. Also, the odds of landscape use were negatively correlated with the average height at the canopy base. Our results suggest multiple habitat factors were related to Northern Goshawk landscape-scale habitat use, similar to habitat use described at smaller spatial scales in the western Great Lakes bioregion and in western North America and Europe.

  18. High-resolution seismic imaging, Mono Lake fault zone, eastern Sierra region, Walker Lane, California

    NASA Astrophysics Data System (ADS)

    Jayko, A. S.; Childs, J. R.; Hart, P. E.; Bursik, M. I.; McClain, J. S.

    2012-12-01

    Multiple strands of the Mono Lake fault zone (MLfz), a segment of the Sierra Nevada frontal fault zone, have been imaged on several high-resolution seismic reflection profiles collected during 2009 and 2011 at Mono Lake. The profiles show coherent reflectors to about 30-40 ms depth below the lake bottom (~30 m thick section) in nearshore areas north of the Lee Vining delta. The MLfz is well imaged on 8 lines including 4 lines ~normal to the trend of the fault zone. The fault zone is ~ 0.75 km wide. Deep reflection horizons appear gently tilted and rotated into the fault zone with a prominent clastic wedge overlying the west-tilted horizons. Shallow reflectors above the clastic wedge are generally east-sloping, but noticeably less inclined above the fault zone. At least two ruptures offset Holocene deposits, with ~0.5-1.8 m dip-slip offset around 2.5 ka and ~3.6-6.13 m dip-slip offset around 4.7 to 6.25 ka. The ages of reflection horizons are estimated using published Holocene and late Pleistocene sedimentation rates, as well as correlation with a published nearby shallow core. The short term fault slip rate based on the timing of the most recent event and multiple events in the profile lines suggests fault slip rates of about 0.26 to 0.55 m/ka using ages based only on sedimentation rate and of about 0.31 to 0.34 m/ka using correlation ages from nearby shallow core. This offshore dip-slip rate is significantly lower than previous published 1.0-2.0 m/ka dip-slip rates estimated using cosmogenic dating of Tioga glacial moraines in Lundy Canyon and offset older moraines. The offset on the large scarp in Lundy Canyon (~20 m) decreases both north and south of the canyon and flanking lateral moraines where the scarp is on the order of only ~4-7 m high. A possible explanation for the apparent difference in MLfz slip rates onshore and offshore in this part of Mono Basin may be soft sediment deformation of saturated glacial-deltaic sediment within Lundy Canyon that causes

  19. Depositional evolution of the Early Cretaceous Sihetun Lake and implications for regional climatic and volcanic history in western Liaoning, NE China

    NASA Astrophysics Data System (ADS)

    Jiang, Baoyu; Fürsich, Franz T.; Hethke, Manja

    2012-06-01

    Numerous well-known fossils of the Jehol Biota, including early birds, feathered theropods, primitive mammals, and putative early angiosperms, have been discovered in lacustrine deposits (Lake Sihetun) of the Lower Cretaceous Yixian Formation of western Liaoning province, NE China. Based on extensive field investigations and four high-resolution excavations, we document in detail the spatio-temporal changes of sedimentary facies, facies associations and limnic community relicts, reconstruct the depositional history, and discuss the significance of these deposits regarding the regional climatic and volcanic history. Four phases are recognized in the history of Lake Sihetun. They are: (1) a phase of fluctuating but gradually rising water level indicated by subaerial and shallow-water lacustrine deposits, (2) a lake with beach-nearshore facies along the marginal areas and suspension-dominated lake floor facies in central areas, (3) a lake phase with a lake floor dominated by hyperpycnal flows, and (4) progradation of a fan delta. Two distinct depositional conditions are observed: stratified and unstratified lake intervals. The former occurred mainly during the second phase and produced clay-poor and clay-rich laminae, whereas the latter developed during the other three phases, and were dominated by deposition of subaqueous sedimentary density flows. These alternations of depositional conditions in offshore lacustrine deposits suggest that the Yixian Formation may have formed under a transitional climate regime fluctuating gradually from warm and dry to warm and humid conditions. Resurgent volcanism is inferred to have become stronger during the late phase of lake development based on distribution of deposits characterizing the unstratified lake interval and volcanic rocks of the overlying Upper Lava unit, a higher content of primary pyroclastic fragments, and evidence of strong syndepositional disturbance.

  20. Watershed influences and in-lake processes - A regional-scale approach to monitoring a water-supply reservoir, Lake Houston near Houston, Texas

    USGS Publications Warehouse

    Oden, Timothy D.; Graham, Jennifer L.

    2008-01-01

    Created in 1954 by an impoundment on the San Jacinto River, Lake Houston currently (2008) supplies about 20 percent of the total source water for the city of Houston. Houston historically has relied on ground water as the major source of supply. As a result of regulations to limit ground-water withdrawals because of associated land subsidence (effective in 2010), the lake will become the primary source of water supply for the city in the future. Since 1983 the U.S. Geological Survey (USGS), in cooperation with the City of Houston, has collected water-quality and lake-level data at Lake Houston, as well as discharge and intermittent water-quality data at its major inflowing tributaries. Previous studies indicate that Lake Houston is shallow, eutrophic, light limited and has a variable hydrologic regime with water residence times ranging from 12 hours to 400 days. Spring Creek, a tributary that drains the western, more urban, part of the Lake Houston watershed, contributes more sediment and nutrients than East Fork San Jacinto River, a tributary that drains the more rural, eastern part of the watershed. This fact sheet explains the importance of monitoring for management of the resource and describes ongoing research in the Lake Houston watershed by the USGS and the City.

  1. Pb isotopes in sediments of Lake Constance, Central Europe constrain the heavy metal pathways and the pollution history of the catchment, the lake and the regional atmosphere

    SciTech Connect

    Kober, B.; Wessels, M.; Bollhoefer, A.; Mangini

    1999-05-01

    Pb isotope ratios and Pb concentrations of well-dated sediments of Lake Constance, Central Europe have been analyzed using thermal ion mass spectrometry. Sequential extraction studies indicated isotope homogeneity of the leachable Pb components within the investigated layers. Since the middle of the 19th century a significant anthropogenic Pb component appeared in the lake sediments, and rapidly approaches concentration levels similar to that of the geogenic Pb background (20 ppm) at the beginning of the 20th century. Anthropogenic Pb was predominantly transferred to the lake sediments via the atmosphere. Pb sources were coal combustion, industrial ore processing and leaded gasoline. The flux of a fluvial Pb component to the lake sediments, additive to atmospheric Pb deposition, peaked in about 1960. This flux is attributed to (re)mobilization of Pb from polluted parts of the lake catchment, and indicates the change of catchment soils from a pollution sink to a heavy metal source. The strong reduction of anthropogenic Pb in the uppermost lake sediments since the 1960s has been caused by advances of environmental protection. The lake sediments record the changing fluxes and the isotope composition of the deposited aeolian Pb pollution. During the 20th century aeolian Pb fluxes to the lake sediments were in the range of 1--4 {micro}g/cm{sup 2}/a. During peak emission periods of gasoline Pb to the atmosphere (1960--1990) the aerosol Pb isotope composition was rather constant ({sup 206}Pb/{sup 207}Pb: 1.12--1.13) and probably a mixture of Canadian and Australian with Russian and Central European Pb types. Aeolian Pb isotope and Pb flux trends in the lake sediments as a whole agree well with the trends found in Alpine glaciers (Doering et al., 1997a,b) and in ombrotrophic peat bogs of Switzerland (Shotyk et al., 1996). However, different industrial Pb components were deposited in the archives of aeolian pollution during the early 20th century.

  2. Biocenotic composition of the macrozoobenthos on different habitats from the littoral region of Lake Ohrid.

    PubMed

    Smiljkov, Stoe; Trajanovski, Saso; Budzakoska-Goreska, Biljana

    2005-12-01

    Biocenotic research on the benthic fauna from the northwestern part of Lake Ohrid, has shown that different habitats characterize different qualitative compositions of the benthic fauna. The affinity of the macrozoobenthic communities to populate different habitats was investigated in 5 different localities from the northwestern part of Lake Ohrid. Among the five different types of habitats such as stony bottom, sandy bottom, sandy-muddy bottom and muddy bottom mostly covered with mollusc shells, it was found that from the qualitative point of view, the sandy-muddy bottom covered with vascular macrophytes is characterized with highest biodiversity of benthic fauna. In all localities, with the exclusion of the locality As (where the macrophytic vegetation is not well developed), the maximum number of species was recorded between depth points from 3 to 11 m. In the Radozda locality, the maximum number of species (11 species) was recorded at a depth point of 6m., on a bottom covered with sandy mud. In the Livadishte locality, the highest biodiversity (13 species) was recorded at a depth points of 5 and 11 m., on bottom covered with sandy mud with well developed macrophytic vegetation. The localities Kalista and Struga, the maximum number of species (14 in Kalista and 11 in Struga) was also recorded in the same type of habitat, a sandy-muddy bottom with well developed macrophytic vegetation. PMID:16400236

  3. Urogenital Schistosomiasis in Women of Reproductive Age in Tanzania's Lake Victoria Region

    PubMed Central

    Downs, Jennifer A.; Mguta, Charles; Kaatano, Godfrey M.; Mitchell, Katrina B.; Bang, Heejung; Simplice, Harusha; Kalluvya, Samuel E.; Changalucha, John M.; Johnson, Warren D.; Fitzgerald, Daniel W.

    2011-01-01

    We conducted a community-based study of 457 women aged 18–50 years living in eight rural villages in northwest Tanzania. The prevalence of female urogenital schistosomiasis (FUS) was 5% overall but ranged from 0% to 11%. FUS was associated with human immunodeficiency virus (HIV) infection (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.2–13.5) and younger age (OR = 5.5 and 95% CI = 1.2–26.3 for ages < 25 years and OR = 8.2 and 95% CI = 1.7–38.4 for ages 25–29 years compared with age > 35 years). Overall HIV prevalence was 5.9% but was 17% among women with FUS. We observed significant geographical clustering of schistosomiasis: northern villages near Lake Victoria had more Schistosoma mansoni infections (P < 0.0001), and southern villages farther from the lake had more S. haematobium (P = 0.002). Our data support the postulate that FUS may be a risk factor for HIV infection and may contribute to the extremely high rates of HIV among young women in sub-Saharan Africa. PMID:21363971

  4. Combined Effect of El Nino Southern Oscillation and Atlantic Multidecadal Oscillation on Lake Chad Level Variability Region

    NASA Technical Reports Server (NTRS)

    Okonkwo, Churchill; Demoz, Belay; Sakai, Ricardo; Ichoku, Charles; Anarado, Chigozie; Adegoke, Jimmy; Amadou, Angelina; Abdullahi, Sanusu Imran

    2015-01-01

    In this study, the combined effect of the Atlantic Multidecadal Oscillation (AMO) and El Niño Southern Oscillation (ENSO) on the Lake Chad (LC) level variability is explored. Our results show that the lake level at the Bol monitoring station has a statistically significant correlation with precipitation (R2 = 0.6, at the 99.5% confidence level). The period between the late 1960s and early 1970s marked a turning point in the response of the regional rainfall to climatic drivers, thereby severely affecting the LC level. Our results also suggest that the negative impact of the cold phase of AMO on Sahel precipitation masks and supersedes the positive effect of La Niña in the early the 1970s. The drop in the size of LC level from 282.5 m in the early 1960s to about 278.1 m in 1983/1984 was the largest to occur within the period of study (1900-2010) and coincides with the combined cold phase of AMO and strong El Niño phase of ENSO. Further analyses show that the current warm phase of AMO and increasing La Niña episodes appear to be playing a major role in the increased precipitation in the Sahel region. The LC level is responding to this increase in precipitation by a gradual recovery, though it is still below the levels of the 1960s. This understanding of the AMO-ENSO-rainfall-LC level association will help in forecasting the impacts of similar combined episodes in the future. These findings also have implications for long-term water resources management in the LC region.

  5. Genetic variation between Schistosoma japonicum lineages from lake and mountainous regions in China revealed by resequencing whole genomes.

    PubMed

    Yin, Mingbo; Liu, Xiao; Xu, Bin; Huang, Jian; Zheng, Qi; Yang, Zhong; Feng, Zheng; Han, Ze-Guang; Hu, Wei

    2016-09-01

    Schistosoma infection is a major cause of morbidity and mortality worldwide. Schistosomiasis japonica is endemic in mainland China along the Yangtze River, typically distributed in two geographical categories of lake and mountainous regions. Study on schistosome genetic diversity is of interest in respect of understanding parasite biology and transmission, and formulating control strategy. Certain genetic variations may be associated with adaptations to different ecological habitats. The aim of this study is to gain insight into Schistosoma japonicum genetic variation, evolutionary origin and associated causes of different geographic lineages through examining homozygous Single Nucleotide Polymorphisms (SNPs) based on resequenced genome data. We collected S. japonicum samples from four sites, three in the lake regions (LR) of mid-east (Guichi and Tonglin in Anhui province, Laogang in Hunan province) and one in mountainous region (MR) (Xichang in Sichuan province) of south-west of China, resequenced their genomes using Next Generation Sequencing (NGS) technology, and made use of the available database of S. japonicum draft genomic sequence as a reference in genome mapping. A total of 14,575 SNPs from 2059 genes were identified in the four lineages. Phylogenetic analysis confirmed significant genetic variation exhibited between the different geographical lineages, and further revealed that the MR Xichang lineage is phylogenetically closer to LR Guich lineage than to other two LR lineages, and the MR lineage might be evolved from LR lineages. More than two thirds of detected SNPs were nonsynonymous; functional annotation of the SNP-containing genes showed that they are involved mainly in biological processes such as signaling and response to stimuli. Notably, unique nonsynonymous SNP variations were detected in 66 genes of MR lineage, inferring possible genetic adaption to mountainous ecological condition. PMID:27207135

  6. The Influences of Climate, Landcover, and In-lake Processes on Nitrogen Solutes and Dissolved Organic Carbon in Small Lake-Watersheds on the Southwestern Adirondack Region of New York

    NASA Astrophysics Data System (ADS)

    Ito, M.; Mitchell, M. J.; Driscoll, C. T.; Kretser, W.; Roy, K. M.

    2001-05-01

    In the Adirondack region of New York where soils and surface waters have been found to be highly sensitive to acidic deposition, precipitation concentrations of nitrate have not declined. In order to understand the responses of lake-watersheds to nitrogen deposition in the Adirondack region and to identify effective approaches to deal with potential problems associated with high N deposition, the factors regulating nitrogen solutes in discharge from lake-watersheds are being evaluated. In the present analysis, nitrogen solutes and dissolved organic carbon in two small lake-watersheds were examined from 1999 to 2000 to assess the influences of climate, land cover, and in-lake processes on these solutes in the southwestern part of the Adirondack region where wet deposition of nitrate and nitrate concentrations in surface waters were higher than in other parts of the Adirondacks. The interrelationships among nitrate, ammonium, dissolved organic nitrogen, and dissolved organic carbon were evaluated to assist in characterizing the influences of the above factors.

  7. Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil.

    PubMed

    Leite, K R B; França, F; Scatena, V I

    2012-02-01

    Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae) - amphibious species; and of Echinodorus grandiflorus (Alismataceae), Eichhornia paniculata (Pontederiaceae) and Habenaria repens (Orchidaceae) - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms. PMID:22437397

  8. Identification of mercury emissions from forest fires, lakes, regional and local sources using measurements in Milwaukee and an inverse method

    NASA Astrophysics Data System (ADS)

    de Foy, B.; Wiedinmyer, C.; Schauer, J. J.

    2012-05-01

    Gaseous elemental mercury is a global pollutant that can lead to serious health concerns via deposition to the biosphere and bio-accumulation in the food chain. Hourly measurements between June 2004 and May 2005 in an urban site (Milwaukee, WI) show elevated levels of mercury in the atmosphere with numerous short-lived peaks as well as longer-lived episodes. The measurements are analyzed with an inverse model to obtain information about mercury emissions. The model is based on high resolution meteorological simulations (WRF), hourly back-trajectories (WRF-FLEXPART) and forward grid simulations (CAMx). The hybrid formulation combining back-trajectories and grid simulations is used to identify potential source regions as well as the impacts of forest fires and lake surface emissions. Uncertainty bounds are estimated using a bootstrap method on the inversions. Comparison with the US Environmental Protection Agency's National Emission Inventory (NEI) and Toxic Release Inventory (TRI) shows that emissions from coal-fired power plants are properly characterized, but emissions from local urban sources, waste incineration and metal processing could be significantly under-estimated. Emissions from the lake surface and from forest fires were found to have significant impacts on mercury levels in Milwaukee, and to be underestimated by a factor of two or more.

  9. Estimation of mercury emissions from forest fires, lakes, regional and local sources using measurements in Milwaukee and an inverse method

    NASA Astrophysics Data System (ADS)

    de Foy, B.; Wiedinmyer, C.; Schauer, J. J.

    2012-10-01

    Gaseous elemental mercury is a global pollutant that can lead to serious health concerns via deposition to the biosphere and bio-accumulation in the food chain. Hourly measurements between June 2004 and May 2005 in an urban site (Milwaukee, WI) show elevated levels of mercury in the atmosphere with numerous short-lived peaks as well as longer-lived episodes. The measurements are analyzed with an inverse model to obtain information about mercury emissions. The model is based on high resolution meteorological simulations (WRF), hourly back-trajectories (WRF-FLEXPART) and a chemical transport model (CAMx). The hybrid formulation combining back-trajectories and Eulerian simulations is used to identify potential source regions as well as the impacts of forest fires and lake surface emissions. Uncertainty bounds are estimated using a bootstrap method on the inversions. Comparison with the US Environmental Protection Agency's National Emission Inventory (NEI) and Toxic Release Inventory (TRI) shows that emissions from coal-fired power plants are properly characterized, but emissions from local urban sources, waste incineration and metal processing could be significantly under-estimated. Emissions from the lake surface and from forest fires were found to have significant impacts on mercury levels in Milwaukee, and to be underestimated by a factor of two or more.

  10. Polybrominated diphenyl ethers and alternative flame retardants in air and precipitation samples from the northern Lake Victoria region, East Africa.

    PubMed

    Arinaitwe, Kenneth; Muir, Derek C G; Kiremire, Bernard T; Fellin, Phil; Li, Henrik; Teixeira, Camilla

    2014-01-01

    High volume air and precipitation samples were collected close to the shore of Lake Victoria at Entebbe, Uganda, between October 2008 and July 2010 inclusive. Polybrominated diphenyl ethers (PBDEs) and alternative flame retardants (AFRs) were analyzed by GC-MS. BDEs 47, 99, and 209 were the predominant PBDEs with mean concentrations (in air) of 9.84, 4.38, 8.27 pg m(-3) and mean fluxes in precipitation of 3.40, 6.23, and 7.82 ng m(-2) sample(-1), respectively. 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and hexabromocyclododecane (HBCDD), anti- and syn-Dechlorane plus were detected at levels comparable with those of PBDEs. Both PBDEs and AFRs in air generally increased from 2008 to 2010. Elevated PBDE concentrations in air were associated with slow moving low altitude air masses from the region immediately adjacent to the lake, while low concentrations were mostly associated with fast moving westerly and southwesterly air masses. Analysis of the octa- and nona-BDE profiles suggested photolysis and pyrolytic debromination of BDE-209 in the air samples. The highly halogenated and most abundant PBDEs and AFRs in air also predominated in precipitation samples. This is the first study to report flame retardants in high volume air samples and precipitation in Equatorial Africa. PMID:24400732

  11. Human-climate interactions in the central Mediterranean region during the last millennia: The laminated record of Lake Butrint (Albania)

    NASA Astrophysics Data System (ADS)

    Morellón, Mario; Anselmetti, Flavio S.; Ariztegui, Daniel; Brushulli, Brunhilda; Sinopoli, Gaia; Wagner, Bernd; Sadori, Laura; Gilli, Adrian; Pambuku, Arben

    2016-03-01

    Lake Butrint (39°47 N, 20°1 E) is a ca. 21 m deep, coastal lagoon located in SW Albania where finely-laminated sediments have been continuously deposited during the last millennia. The multi-proxy analysis (sedimentology, high-resolution elemental geochemistry and pollen) of a 12 m long sediment core, supported by seven AMS radiocarbon dates and 137Cs dating, enable a precise reconstruction of the environmental change that occurred in the central Mediterranean region during the last ∼4.5 cal kyrs BP. Sediments consist of triplets of authigenic carbonates, organic matter and clayey laminae. Fluctuations in the thickness and/or presence of these different types of seasonal laminae indicate variations in water salinity, organic productivity and runoff in the lake's catchment, as a result of the complex interplay of tectonics, anthropogenic forcing and climate variability. The progradation of the Pavllo river delta, favoured by variable human activity from the nearby ancient city of Butrint, led to the progressive isolation of this hydrological system from the Ionian Sea. The system evolved from an open bay to a restricted lagoon, which is consistent with archaeological data. An abrupt increase in mass-wasting activity between 1515 and 1450 BC, likely caused by nearby seismic activity, led to the accumulation of 24 homogenites, up to 17 cm thick. They have been deposited during the onset of finely laminated sedimentation, which indicates restricted, anoxic bottom water conditions and higher salinity. Periods of maximum water salinity, biological productivity, and carbonate precipitation coincide with warmer intervals, such as the early Roman Warm Period (RWP) (500 BC-0 AD), the Medieval Climate Anomaly (MCA) (800-1400 AD) and recent times (after 1800 AD). Conversely, lower salinity and more oxic conditions, with higher clastic input were recorded during 1400-500 BC, the Late Roman and the Early Medieval periods (0-800 AD) and during the Little Ice Age (1400-1800 AD

  12. Biogeochemistry of a submerged groundwater seep ecosystem in Lake Huron near karst region of Alpena, MI

    NASA Astrophysics Data System (ADS)

    Kinsman-Costello, L. E.; Dick, G.; Sheik, C.; Burton, G. A.; Sheldon, N. D.

    2015-12-01

    Submerged groundwater seeps in Lake Huron establish ecosystems with distinctive geochemical conditions. In the Middle Island Sinkhole (MIS), a 23-m deep seep, groundwater seepage establishes low O2 (< 4 mg L-1), high sulfate (6 mM) conditions, in which a purple cyanobacteria-dominated mat thrives. The mat is capable of anoxygenic photosynthesis, oxygenic photosynthesis, and chemosynthesis. Within the top 3 cm of the mat-water interface, hydrogen sulfide concentrations increase to 1-7 mM. Little is known about the structure and function of microbes within organic-rich, high-sulfide sediments beneath the mat. Using pore water and sediment geochemical characterization along with microbial community analysis, we elucidated relationships between microbial community structure and ecosystem function along vertical gradients. In sediment pore waters, biologically reactive solutes (SO42-, NH4+, PO43-, and CH4) displayed steep vertical gradients, reflecting biological and geochemical functioning. In contrast, more conservative ions (Ca+2, Mg+2, Na+, and Cl-), did not change significantly with depth in MIS sediments, indicating groundwater influence in the sediment profile. MIS sediments contained more organic matter than typical Lake Huron sediments, and were generally higher in nutrients, metals, and sulfur (acid volatile sulfide). Using the Illumina MiSeq platform we detected 14,127 unique operational taxonomic units across sediment and surface mat samples. Microbial community composition in the MIS was distinctly different from non-groundwater affected areas at similar depth nearby in Lake Huron (ANOSIM, R= 0.74, p=0.002). MIS sediment communities were more diverse that MIS surface mat communities and changed with depth into sediments. MIS sediment community composition was related to several geochemical variables, including organic matter and multiple indicators of phosphorus availability. Elucidating the structure and function of microbial consortia in MIS, a highly

  13. Declining Snow Cover Reduces Radiative Cooling from Historic Land Use Change in the Western Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Blakely, B.; Rocha, A. V.; McLachlan, J. S.

    2015-12-01

    The Anthropocene is characterized by rapid changes in both land use and snow cover. The relative importance of these two forces remains unknown but may have important and long-term biophysical effects that are not adequately incorporated into current modeling efforts. Humans have altered the landscape of the Eastern U.S. both historically through deforestation during European settlement and more recently through climatic reductions in snow cover. Here we empirically reconstruct historic albedo in the Eastern U.S. using both modern and historic data. We focus on the Western Great Lakes region (MI, WI, MN, IL, IN), a global hotspot of historic deforestation that spans latitudes where anthropogenic climate modifications have produced important changes in snow cover. We find that vegetation changes have caused an overall increase in regional albedo that is strongest where intensive land use persists (i.e. agriculture) and weakest where forest regrowth has occurred. Changes in snow cover have caused an overall decrease in regional albedo that is about half as strong as increase in albedo due to vegetation change. Although the negative forcings of historic land use change may currently provide a radiative 'discount' on regional warming, these benefits are likely to disappear with time as snow cover decreases and forest regrowth continues.

  14. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

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

  15. Assessing the influence of water level on schistosomiasis in Dongting Lake region before and after the construction of Three Gorges Dam.

    PubMed

    Li, Zhongwu; Nie, Xiaodong; Zhang, Yan; Huang, Jinquan; Huang, Bin; Zeng, Guangming

    2016-01-01

    Schistosomiasis is a severe public health problem in the Dongting Lake region, and its distribution, prevalence, and intensity of infection are particularly sensitive to environmental changes. In this study, the human and bovine schistosomiasis variations in the Dongting Lake region were studied from 1996 to 2010, and the relationships between schistosomiasis and water level were examined. Furthermore, based on these results, the potential effects of the Three Gorges Dam (TGD) on schistosomiasis were investigated. Results showed an increase in human schistosomiasis and in the scope of seriously affected regions, along with a decrease in bovine schistosomiasis. Human schistosomiasis was negatively correlated with water level during wet season (from May to October), particularly the average water level in October. This finding indicated that the decreasing water level may be highly related to the increasing of human schistosomiasis in the Dongting Lake region. Based on this result and the variation of schistosomiasis before and after the construction and operation of TGD, the impoundment of the Three Gorges reservoir is believed to decrease the water level and increase the contact between people and schistosomiasis. Therefore, the TGD, which is operated by regulating water and scheduling water operations, is not good for the control of human schistosomiasis in the Dongting Lake region. Although the extent of the influence of the TGD on schistosomiasis remains unclear, the influence of the TGD on preventing and controlling schistosomiasis should not be ignored. PMID:26661964

  16. Measuring the embodied energy in drinking water supply systems: a case study in the Great Lakes region.

    PubMed

    Mo, Weiwei; Nasiri, Fuzhan; Eckelman, Matthew J; Zhang, Qiong; Zimmerman, Julie B

    2010-12-15

    A sustainable supply of both energy and water is critical to long-term national security, effective climate policy, natural resource sustainability, and social wellbeing. These two critical resources are inextricably and reciprocally linked; the production of energy requires large volumes of water, while the treatment and distribution of water is also significantly dependent upon energy. In this paper, a hybrid analysis approach is proposed to estimate embodied energy and to perform a structural path analysis of drinking water supply systems. The applicability of this approach is then tested through a case study of a large municipal water utility (city of Kalamazoo) in the Great Lakes region to provide insights on the issues of water-energy pricing and carbon footprints. Kalamazoo drinking water requires approximately 9.2 MJ/m(3) of energy to produce, 30% of which is associated with indirect inputs such as system construction and treatment chemicals. PMID:21105699

  17. The impact of educational videotapes on water contact behaviour of primary school students in the Dongting Lakes region, China.

    PubMed

    Yuan, L; Manderson, L; Tempongko, M S; Wei, W; Aiguo, P

    2000-08-01

    Multimedia has become increasingly important in educational programmes in schools in all societies, and has potential value for health education. We developed a video and a comic book on the transmission and prevention of schistosomiasis for use in primary schools in endemic areas of China. The material was designed to increase children's knowledge of schistosomiasis as an environmental disease and to encourage them to reduce their contact with unsafe water sources. To test the effectiveness of the video and booklet, a quasi-experimental study was conducted among 1,739 children in 50 primary schools in the Dongting Lake region. A self-administered questionnaire pre- and post-intervention showed a significant increase in knowledge about schistosomiasis in the intervention schools. Significantly, this change was associated with a decrease in contact with unsafe water sources, as established from water contact observations. This behavioural change suggests the value of short, targeted educational interventions to decrease risk of infection. PMID:10995095

  18. The Thermal History of the East African Rift Lakes Region Since the Last Glacial Maximum Using TEX86 Paleothermometry

    NASA Astrophysics Data System (ADS)

    Berke, M. A.; Johnson, T. C.; Werne, J. P.; Schouten, S.; Sinninghe Damsté, J. S.

    2008-12-01

    We present preliminary results from a study using the TEX86 temperature proxy from sediments of East African Rift Lakes (including Lakes Turkana, Albert, and Malawi) to reconstruct the thermal history of tropical Africa for the last ~ 20,000 years at a subcentennial to multicentennial resolution. The TEX86 proxy, based on tetraether membrane lipids produced by lacustrine Crenarchaeota, has been shown to be successful at recording lake surface temperatures of some large lakes, including Lakes Malawi and Tanganyika, while providing unreasonable surface temperatures for lakes that receive a large input of soil material. The East African Rift Lakes are climatically sensitive, with the majority of water loss due to evaporation rather than outflow. Thus, they are useful for paleoclimate studies, being sensitive to even small changes in aridity. Temperature records from the northern and central basins of Lake Malawi agree well and fall within modern surface lake temperatures. A 2.5°C cooling is evident during the Younger Dryas in the northern basin record, with no response seen in the central basin. We are currently investigating mechanisms to explain why both records show a gradual cooling of 3°C during the late Holocene. Lake Albert shows an intriguing two-step cooling during the Younger Dryas, reaching temperatures 2.5°C lower than temperatures preceding or following this interval. The temperature record of Lake Turkana shows an interesting ~ 500 year cyclicity of low temperatures punctuated by abrupt warming events. Lakes Turkana and Albert show TEX86 paleotemperatures considerably lower (8°C cooler in Lake Albert and ~ 4°C cooler in Lake Turkana) than modern surface water temperatures. Although these records appear to fall in the range of temporal variability, these temperature discrepancies may indicate varying Crenarcheotal populations between lakes or other influencing factors.

  19. Regional Reconstruction of Fire and Climate in Western Mongolia During the Past 1000 Years: Modern Lake Systems and Their Connection With Climate

    NASA Astrophysics Data System (ADS)

    Shinneman, A. L.; Umbanhowar, C. E.; Edlund, M. B.; Soninkhishig, N.

    2007-12-01

    The Valley of the Great Lakes in western Mongolia is a unique ecosystem comprising a wide variety of terrestrial and aquatic habitats. Little is known about the long-term history of the region or the relative impact of climate and land-use on ecosystem development. A hydrobiological survey from 2004-2005 has elucidated patterns in the distribution of aquatic biota (ostracodes, diatoms, and chironomids) as well as patterns in lake sedimentation and terrestrial inputs (based on charcoal, loss-on-ignition, and sediment magnetic properties) related to modern climate and land-use. Over 50 modern lacustrine systems were sampled, allowing for a greater understanding of modern processes in this unique system as well as offering a method for calibration and interpretation of long- term sediment records recovered from the lakes. Low concentrations of charcoal were found in only 30% of surface samples (those fringed by thick bands of Phragmites) suggesting that fire is not a common feature in the modern landscape. Across sample sites organic content of lake sediments (2-50%) decreased from east to west and the concentration and size of magnetic particles (IRM) increased, likely reflecting decreases in effective annual precipitation. Variability in the chemical and biological characteristics among sampled lakes is strongly controlled by the precipitation to evaporation balance; ionic composition varies with lake salinity and both the composition and concentration of salts are dominant factors controlling the species diversity and richness among all sampled taxonomic groups. Correspondence analysis (CCA) demonstrates that both salinity and total phosphorous concentrations account for unique and significant fractions of the observed variability in diatom communities among the lakes, allowing for the development of inference models for down-core analyses. Using these diatom-based inference models along with a modern calibration of lake sedimentation patterns, down core changes

  20. [Effects of different rotation systems on greenhouse gas (CH₄ and N₂O) emissions in the Taihu Lake region, China].

    PubMed

    Hu, An-yong; Sun, Xing; Liu, Qin

    2016-01-01

    We conducted a greenhouse gas emissions study of different rice-based cropping systems in the Taihu Lake region. The results indicated that the seasonal CH₄ emission initially increased, but declined over time. CH₄emission mainly occurred during the early stages of rice growth and decreased after the paddy soil dried. N₂O emission mainly occurred during the fertilizer application and paddy field drying stages. Compared with N20 emission, CH₄ emission contributed significantly more to the global warming potential (GWP) during the rice season. The proportion of CH4 emission to the total greenhouse gas emissions, which this study aimed to reduce, ranged from 94.7%-99.6%. CH₄emissions and their GWP during the rice season varied significantly under different rotation systems, with the order of wheat-rice rotation>Chinese milk vetch-rice rotation>fallow-rice rotation, while the N2O emissions and their GWP exhibited no significant differences. Compared with no nitrogen fertilization, applying N fertilizer significantly reduced CH₄ emission and GWP of the Chinese milk vetch-rice rotation. However, CH₄ emission and GWP did not vary with N application rates. The rice yield was largest when the N application rate was 240 kg · hm⁻². Taking economic and environmental benefits into account, we found that a N application rate of 240 kg · hm⁻² and a straw-return application of Chinese milk vetch not only reduced greenhouse gas emissions but also achieved the highest rice grain yield, which was recommended as a suitable cropping system for the Taihu Lake region. PMID:27228598

  1. Economic optimal nitrogen application rates for rice cropping in the Taihu Lake region of China: taking account of negative externalities

    NASA Astrophysics Data System (ADS)

    Xia, Y.; Yan, X.

    2011-07-01

    Nitrogen application rates (NARs) is often overestimated over the rice (Oryza sativa L.) growing season in the Taihu Lake region of China. This is largely because only individual nitrogen (N) losses are taken into account, or the inventory flows of reactive N have been limited solely to the farming process when evaluating environmental and economic effects of N fertilizer. Since N can permeate the ecosystem in numerous forms commencing from the acquisition of raw material, through manufacturing and use, to final losses in the farming process (e.g., N2O, NH3, NO3- leaching, etc.), the costs incurred also accumulate and should be taken into account if economically-optimal N rates (EONRs) are to be established. This study integrates important material and energy flows resulting from N use into a rice agricultural inventory that constitutes the hub of the life-cycle assessment (LCA) method. An economic evaluation is used to determine an environmental and economic NAR for the Taihu Lake region. The analysis reveals that production and exploitation processes consume the largest proportion of resources, accounting for 77.2 % and 22.3 % of total resources, respectively. Regarding environmental impact, global warming creates the highest cost with contributions stemming mostly from fertilizer production and raw material exploitation processes. Farming process incurs the biggest environmental impact of the three environmental impact categories considered, whereas transportation has a much smaller effect. When taking account of resource consumption and environmental cost, the marginal benefit of 1 kg rice would decrease from 2.4 to only 1.01 yuan. Accordingly, our current EONR has been evaluated at 185 kg N ha-1 for a single rice-growing season. This could enhance profitability, as well as reduce the N losses associated with rice growing.

  2. Identification of glacier motion and potentially dangerous glacial lakes in the Mt. Everest region/Nepal using spaceborne imagery

    NASA Astrophysics Data System (ADS)

    Bolch, T.; Buchroithner, M. F.; Peters, J.; Baessler, M.; Bajracharya, S.

    2008-12-01

    Failures of glacial lake dams can cause outburst floods and represents a serious hazard. The potential danger of outburst floods depends on various factors like the lake's area and volume, glacier change, morphometry of the glacier and its surrounding moraines and valley, and glacier velocity. Remote sensing offers an efficient tool for displacement calculations and risk assessment of the identification of potentially dangerous glacial lakes (PDGLs) and is especially helpful for remote mountainous areas. Not all important parameters can, however, be obtained using spaceborne imagery. Additional interpretation by an expert is required. ASTER data has a suitable accuracy to calculate surface velocity. Ikonos data offers more detail but requires more effort for rectification. All investigated debris-covered glacier tongues show areas with no or very slow movement rates. From 1962 to 2003 the number and area of glacial lakes increased, dominated by the occurrence and almost linear areal expansion of the moraine-dammed lakes, like the Imja Lake. Although the Imja Lake will probably still grow in the near future, the risk of an outburst flood (GLOF) is considered not higher than for other glacial lakes in the area. Potentially dangerous lakes and areas of lake development are identified. There is a high probability of further lake development at Khumbu Glacier, but a low one at Lhotse Glacier.

  3. A spatially explicit model of runoff, evaporation, and lake extent: Application to modern and late Pleistocene lakes in the Great Basin region, western United States

    NASA Astrophysics Data System (ADS)

    Matsubara, Yo; Howard, Alan D.

    2009-06-01

    A spatially explicit hydrological model was applied to the Great Basin in the western United States to predict runoff magnitude and lake distributions under modern and late Pleistocene conditions. The model iteratively routes runoff through depression to find a steady state solution and was calibrated with mean annual precipitation, pan evaporation, temperature, and stream runoff data. The predicted lake distribution provides a close match to present-day lakes. For the late Pleistocene, the sizes of lakes Bonneville and Lahontan are well predicted by linear combinations of 0.2°-5.8°C decreases in temperature and corresponding increases in precipitation from 2.0 to 1.0 times modern values. This corresponds to runoff depths ranging from 1.7 to 4.1 times the present values and yearly evaporation from 0.4 to 1 times modern values. To reproduce Lake Manly, however, combinations of temperature decreases up to 9°C or precipitation up to 2.8 times the present values were required.

  4. Reconstructions of the ecological conditions of the Holocene in the region of Steppe Altay, using sediment archives of the Lake Yarovoe

    NASA Astrophysics Data System (ADS)

    Nazarova, Larisa; Nourgaliev, Danis; Frolova, Larisa; Palagushkina, Olga; Rudaya, Natalia; Krylov, Pavel; Kosareva, Lina; Gafiatullina, Lilia; Gilmanova, Dilara

    2010-05-01

    The Altai Mountains are located in the center of climatologically sensitive region. Here, major polar and subpolar air masses meet, making Altai Mountain region to an ideal place to record shifts in atmospheric circulation. Due to its position in the center of the Eurasian continent, it is a key region for studying the past variations in the Arctic monsoon strength, the Siberian high pressure system, and the Westerlies that bring North Atlantic moisture to the interior of Eurasia. The precipitation in the Altai Mountains is mainly driven by cyclonic activities and monsoons. Any small change in global atmospheric circulation causes a distinct change in the regional climate, i.e. in temperature and precipitation of this area, and leads to sharp changes of vegetation and landscapes. As a result, there are ecologically contrasting biomes such as mountainous conifer forests, dry steppe and high mountain meadows and tundra vegetation within relatively short distances, depending on elevation, and slope aspect. Lake Bolshoe Yarovoe (52°56´00˝ N and 78°35´00˝ E.) is the deepest one among the lakes in Kulundin steppe. It is situated in the lowest place of the Alaty region (79 м a.s.l.). The total area of the lake constitute 70 square km with the maximal depth averaging at 25 m. Sediments of the lake were investigated with the methods of mineralogical, lithological, palaeomagnetic analysis and using paleolimnological proxies (pollen, diatoms, cladocera, chironomids). After the correlation of our data with the world data (Lake Biwa, Japan), we found that the oldest part of the investigated cores are 4,5 ka old. Preliminary seismographical interpretation of the obtained data allows us to suppose a considerable strong influence of neotectonical, palaeogeographical and other factors on the processes of sedimentation in the lake Bolshoe Jarovoe. Seismoacustical investigations have revealed presence of the mud vulcanism in the lake, areas that are influenced by thermal

  5. [Study on solid surface fluorescence characteristic of saline soils around lakes in arid and semiarid regions].

    PubMed

    Yu, Hui-bin; Xi, Bei-dou; Wei, Zi-min; Ma, Wen-chao; He, Xiao-song; Guo, Xu-jing; Liu, Hong-liang

    2010-10-01

    Fluorescence spectroscopy relies on the fluorescence emitted by rigid conjugated systems and thus has been increasingly used to assess the soil organic matter (SOM) humification. This technique is widely applied to solution samples of humic substances, and so far no information exists about its applicability to solid-phase soil samples. Composite soil samples of different depths (0-20, 20-40 and 40-60 cm) were collected from four different halophyte communities along a saline-impact gradient, namely, Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA) located around Wuliangsuhai Lake. A humification index based on solid surface fluorescence spectroscopy (HIX(SSF)) was proposed, and compared with conventional humification indices I400/I360, I470/I360, I465/I399 and A4 /Al. There were close positive linear correlations between HIXass and 1400/1360, 145/I399 and A4/A1, but a poor positive linear correlation existed between the HIX(SSF) and I470/I360. The results indicated that HIX(SSF) can be taken as a tool to assess the soil humi fication. The HIX(SSF) of the CSE and CSG varied inappreciably within soil profiles and there was no trend with depth. However the HIX(SSF) varied appreciably in the CKF and CSA, and the HIX(SSF) of the bottom soil profile was higher than that of the other profiles. As a whole, the soil humification degree was low around Wuliangsuhai Lake, and the ecological environment was relatively fragile. The salinity showed a strong negative linear relationship with the I400/I360, I470/I360, I465/I399 and A4/A1, but a good negative linear relationship with the HIX(SSF). The results indicated that the degree of the SOM humification increased with the drop in the salinity. The HIX(SSF) can be an indicator not only of the degree of SOM humification, but also of the process of the salinisation. PMID:21137399

  6. EVALUATING THE REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL (R-MCM) FOR LAKES ACROSS VERMONT AND NEW HAMPSHIRE, USA

    EPA Science Inventory

    Regulatory agencies are confronted with a daunting task of developing fish consumption advisories for a large number of lakes and rivers with little resources. A feasible mechanism to develop region-wide fish advisories is by using a process-based mathematical model. One model of...

  7. Capacity Building for Disaster Management in Vulnerable Regions of Africa: Implementing an Operational Flood Warming System in Lake Victoria

    NASA Astrophysics Data System (ADS)

    Hong, Y.; Li, L.; Adler, R.; Policelli, F.

    2008-12-01

    NASA Applied Science program has partnered with USAID and The Regional Centre for Mapping of Resources for Development (RCMRD) in Africa to implement an operational flood warning system for East Africa, SERVIR-Africa project. The project seeks to take advantage of remote sensing information as an alternative and supplemental to ground-based observation in order to preserve the spatial extent of flood hazards. The recently available and virtually uninterrupted supply of satellite-based rainfall estimates is increasingly becoming a cost-effective data source for flood prediction in many under-gauged regions around the world. Our initial focus aims to provide an operational flood warning system for Lake Victoria, a flood-prone region home to 30 million people. The key datasets enabling the development of a distributed hydrological model in Africa include TRMM-based Multi-satellite Precipitation Analysis (TMPA), digital elevation data from the Shuttle Radar Topography Mission (SRTM) mission, HydroSHEDS hydrological products, MODIS Land cover, and soil parameters provided by FAO. This research focuses on evaluation and integration the TMPA Real- Time product into an online operational flood prediction system. We will also identify the optimal calibration strategy for satellite rainfall data into real-time hydrological modeling, one current knowledge gap that has remained relatively unexplored. Early results demonstrate this flood modeling system is useful decision- support tool for governmental officials and international aid organizations to better quantify flood impacts and extent of hazard risk, as well as more expediently respond to flood emergencies.

  8. Quantifying understorey vegetation in the US Lake States: a proposed framework to inform regional forest carbon stocks

    USGS Publications Warehouse

    Russell, Matthew B.; D'Amato, Anthony W.; Schulz, Bethany K.; Woodall, Christopher W.; Domke, Grant M.; Bradford, John B.

    2014-01-01

    The contribution of understorey vegetation (UVEG) to forest ecosystem biomass and carbon (C) across diverse forest types has, to date, eluded quantification at regional and national scales. Efforts to quantify UVEG C have been limited to field-intensive studies or broad-scale modelling approaches lacking field measurements. Although large-scale inventories of UVEG C are not common, species- and community-level inventories of vegetation structure are available and may prove useful in quantifying UVEG C stocks. This analysis developed a general framework for estimating UVEG C stocks by employing per cent cover estimates of UVEG from a region-wide forest inventory coupled with an estimate of maximum UVEG C across the US Lake States (i.e. Michigan, Minnesota and Wisconsin). Estimates of UVEG C stocks from this approach reasonably align with expected C stocks in the study region, ranging from 0.86 ± 0.06 Mg ha-1 in red pine-dominated to 1.59 ± 0.06 Mg ha-1 for aspen/birch-dominated forest types. Although the data employed here were originally collected to assess broad-scale forest structure and diversity, this study proposes a framework for using UVEG inventories as a foundation for estimating C stocks in an often overlooked, yet important ecosystem C pool.

  9. Reducing uncertainties associated with remotely sensed estimates of forest growth and carbon exchange in the Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Cook, Bruce Douglas

    NASA satellites Terra and Aqua orbit the Earth every 100 minutes and collect data that is used to compute an 8 day time series of gross photosynthesis and annual plant production for each square kilometer of the earth's surface. This is a remarkable technological and scientific achievement that permits continuous monitoring of plant production and quantification of CO2 fixed by the terrestrial biosphere. It also allows natural resource scientists and practitioners to identify global trends associated with land cover/use and climate change. Satellite-derived estimates of photosynthesis and plant production from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) generally agree with independent measurements from validation sites across the globe, but local biases and spatial uncertainties exist at the regional scale. This dissertation evaluates three sources of uncertainty associated with MODIS algorithms in the Great Lakes Region, and evaluates LiDAR (Light Detection and Ranging) remote sensing as a method for improving model inputs. Chapter 1 examines the robustness of model parameters and errors resulting from canopy disturbances, which were assessed by inversion of flux tower observations during a severe outbreak of forest tent caterpillars. Chapter 2 examines model logic errors in wetland ecosystems, focusing on surface water table fluctuations as a potential constraint to photosynthesis that is not accounted for in the MODIS algorithm. Chapter 3 examines errors associated with pixel size and poor state data, using fine spatial resolution LiDAR and multispectral satellite data to derive estimates plant production across a heterogeneous landscape in northern Wisconsin. Together, these papers indicate that light- and carbon-use efficiency models driven by remote sensing and surface meteorology data are capable of providing accurate estimates of plant production within stands and across landscapes of the Great Lakes Region. It is demonstrated that model

  10. Variability of the atmospheric turbulence in the region lake of Baykal

    NASA Astrophysics Data System (ADS)

    Botygina, N. N.; Kopylov, E. A.; Lukin, V. P.; Kovadlo, P. G.; Shihovcev, A. Yu.

    2015-11-01

    The estimations of the fried parameter according to micrometeorological and optical measurements in the atmospheric surface layer in the area of lake Baikal, Baikal astrophysical Observatory. According to the archive of NCEP/NCAR Reanalysis data obtained vertical distribution of temperature pulsations, and revealed the most pronounced atmospheric layers with high turbulence. A comparison of astronomical conditions vision in winter and in summer. By the registration of optical radiation of the Sun with telescopes, ground-based there is a need to compensate for the effects of atmospheric turbulence. Atmospheric turbulence reduces the angular resolution of the observed objects and distorts the structure of the obtained images. To improve image quality, and ideally closer to angular resolution, limited only by diffraction, it is necessary to implement and use adaptive optics system. The specificity of image correction using adaptive optics is that it is necessary not only to compensate for the random jitter of the image as a whole, but also adjust the geometry of the individual parts of the image. Evaluation of atmospheric radius of coherence (Fried parameter) are of interest not only for site-testing research space, but also are the basis for the efficient operation of adaptive optical systems 1 .

  11. Best Practices for Sustainable WInd Energy Development in the Great Lakes Region and Beyond

    SciTech Connect

    Great Lakes Commission; Victoria Pebbles; John Hummer; Celia Haven

    2011-07-19

    This document offers a menu of 18 different, yet complimentary preferred practices and policies. The best practices cover all phases of the wind energy development process - from the policies that allow for wind development, to the sustainable operation of a wind project, to the best practices for decommissioning a spent turbine - including applications for offshore wind. The practices include those that have been previously tested and proven effective, as well as new practices that were identified by experts in the field as needed for future wind developments. Each best practice includes information about the opportunities and challenges (pros and cons), and offers a case example that illustrates how that best practice is being utilized by a particular jurisdiction or wind project. The practices described in this publication were selected by a diverse group of interests from the Great Lakes Wind Collaborative that included environmental groups, industry, and federal, state and local government regulators. They were identified through a year long process that included a literature review, online survey and interviews with individuals from the public, private and non-profit sectors.

  12. Chemical pollution in inland shallow lakes in the Mediterranean region (NW Spain): PAHs, insecticides and herbicides in water and sediments.

    PubMed

    Hijosa-Valsero, María; Bécares, Eloy; Fernández-Aláez, Camino; Fernández-Aláez, Margarita; Mayo, Rebeca; Jiménez, Juan José

    2016-02-15

    The possible effect of land uses and human-related geographic patterns (presence of roads and urban settlements) on chemical pollution was evaluated in the waters and sediments of fifty-three Mediterranean shallow lakes. The presence of fifty-nine pollutants (belonging to PAHs, insecticides and herbicides groups) was analysed in these lakes by GC-MS. The studied lakes had similar pollutant concentrations to other lakes worldwide. The distribution of the compounds between water and sediment compartments was strongly influenced by log K(ow) values (an average of 3.61 for compounds found in water and of 4.69 for compounds found in sediments). A multivariate analysis suggested that the concentration of PAHs in water could be related to agricultural activities and not related to local road traffic. When assessing nutrient levels in the lakes, it was observed that eutrophicated lakes [>300 μg L(-1) total phosphorus (TP)] appeared in areas affected by urban or industrial use (at least 2% urban use in a 1-km radius around the lake), whilst lakes with lower TP concentrations were placed in forest areas (60% of forest use in a 1-km radius); in addition, the aqueous concentrations of Σ(PAH) were lower in lakes with higher TP concentrations (>150 μg L(-1) TP), which could be related to the adsorption capacity of PAHs onto suspended matter which is present in mesotrophic and eutrophic lakes, thus being removed from the aqueous phase. PMID:26688052

  13. Mercury exposure and reproduction in fish-eating birds breeding in the Pinchi Lake region, British Columbia, Canada.

    PubMed

    Weech, Shari A; Scheuhammer, Anton M; Elliott, John E

    2006-05-01

    To determine whether Hg from geologic/mining-related sources at Pinchi Lake (BC, Canada) was causing elevated Hg exposure and/or adversely affecting reproduction in fish-eating birds, breeding bald eagles (Haliaeetus leucocephalus) on Pinchi Lake and four nearby reference lakes were sampled for blood and feather Hg concentrations and monitored for reproductive success during the summers of 2000, 2001, and 2002. Eggs of red-necked grebes (Podiceps grisgena) also were collected and analyzed. Mercury levels in species at various trophic levels from Pinchi Lake averaged approximately twice those in the same species from nearby lakes combined, even in the absence of substantial new inputs of Hg to Pinchi Lake over several decades. In Pinchi Lake, Hg concentrations in blood and feathers of eagles and eggs of grebes were significantly higher than those in corresponding samples from reference lakes. However, the mean Hg concentration (0.25 microg/g wet wt) in grebe eggs from Pinchi Lake was substantially lower than accepted threshold levels for reproductive toxicity in most avian species (0.5-1.0 microg/g wet wt). Mercury concentrations in the blood of adult eagles and their chicks were highly correlated (r = 0.91, p = 0.004). Despite elevated Hg exposure in adult eagles nesting on Pinchi Lake (blood Hg concentration, 4.3-9.4 microg/ml), birds appeared to be in good body condition, did not differ significantly in terms of weight from eagles nesting on reference lakes, and exhibited no evidence of obvious abnormal behavior or lack of coordination. Eagle reproductive success and productivity on Pinchi Lake were not significantly different from those on all reference lakes combined (p = 0.483). PMID:16704079

  14. Characteristics Of Atmospheric Dry Deposition Of Metals To The Region Of Lake Asan And Sapgyo, Korea

    NASA Astrophysics Data System (ADS)

    Han, J.; Shin, H.; Lee, M.; Lim, Y.; Seo, M.; Jung, I.

    2008-12-01

    Environment includes a multi-media such as air, surface water, soil, underground water and ecosystem. Some pollutants transfer among a multi-media, posing serious threat to humans, animals and plants. Pollutants released into the environment remain for long times and transport long distances while going through physical and chemical interactions such as transports between multi-media ; air, water and soil, deposition, and absorption and release from organisms. This study assessed the amount of heavy metals transferred from air to water and soil using dry deposition plate and water surface sampler during spring (June 13 ~ 21, 2007) and winter (October 23 ~ 30 in 2007) at 9 locations including Dangjin, Pyeongtaek and Asan. Micro-Orifice Uniform Deposit Impactor, MOUDI was used to confirm the size distribution. The measured heavy metal deposition flux was compared with the expectation obtained with deposition model. In addition, amount of heavy metal deposition at Asan and Sapgyo lakes were evaluated to verify the water pollution state driven by atmospheric deposition. Atmospheric dry deposition flux of metals are 133.92 microgram m-2 day-1, 44.01 microgram m-2 day-1, 0.915 microgram m-2 day-1, and 0.175 microgram m-2 day-1 during spring, and 72.86 microgram m-2 day- 1, 88.14 microgram m-2 day-1, 0.991 microgram m-2 day-1, and 0.189 microgram m-2 day-1 during fall, for lead, nickel, arsenic, and cadmium, respectively. It is required to re- calculation the dry deposition flux by land use type due to possibility of underestimating the flux in case of using grease surrogate surface having low surface roughness. The cadmium, lead, and arsenic size distribution was mono-modal with the peaks in the 0.65 ~ 1.1 micrometer size range in the fine mode showing sharp peak in the condensation submode especially for cadmium and lead because of effect of primary emission. The nickel size distribution was bimodal, a typical size distribution for an urban atmosphere, showing sharp

  15. Distribution and Fate of Black Carbon Nanoparticles from Regional Urban Pollution and Wildfire at a Large Subalpine Lake in the Western United States

    NASA Astrophysics Data System (ADS)

    Bisiaux, M. M.; Heyvaert, A. C.; Edwards, R.

    2012-04-01

    Emitted to the atmosphere through fire and fossil fuel combustion, refractory black carbon nanoparticles (rBC) impact human health, climate, atmospheric chemistry, and the carbon cycle. Eventually these particles enter aquatic environments, where their distribution, fate and association with other pollutants are still poorly characterized. This study presents results from an evaluation of rBC in the waters of oligotrophic Lake Tahoe and its watershed in the western United States. The study period included a large wildfire within the Tahoe basin, seasonal snowmelt, and a number of storm events that resulted in pulsed urban runoff into the lake with rBC concentrations up to four orders of magnitude higher than mid-lake concentrations. The results show that elevated rBC concentrations from wildfire and urban runoff were rapidly attenuated in the lake, suggesting unexpected aggregation or degradation of the particles that prevent rBC concentrations from building up in the water of this lake, renowned for its clarity. The rBC concentrations were also measured in sediment cores from Lake Tahoe to evaluate the sediment archive as a potential combustion record. The evidence suggests that rBC is efficiently transferred to these sediments, which preserve a local-to-regional scale history of rBC emissions, as revealed by comparison with other pollutant records in the sediment. Rapid removal of rBC soon after entry into the lake has implications for transport of rBC in the global aquatic environment and flux of rBC from continents to the global ocean.

  16. Maintaining yields and reducing nitrogen loss in rice-wheat rotation system in Taihu Lake region with proper fertilizer management

    NASA Astrophysics Data System (ADS)

    Xue, Lihong; Yu, Yingliang; Yang, Linzhang

    2014-11-01

    In the Tailake region of China, heavy nitrogen (N) loss of rice-wheat rotation systems, due to high fertilizer-N input with low N use efficiency (NUE), was widely reported. To alleviate the detrimental impacts caused by N loss, it is necessary to improve the fertilizer management practices. Therefore, a 3 yr field experiments with different N managements including organic combined chemical N treatment (OCN, 390 kg N ha-1 yr-1, 20% organic fertilizer), control-released urea treatment (CRU, 390 kg N ha-1 yr-1, 70% resin-coated urea), reduced chemical N treatment (RCN, 390 kg N ha-1 yr-1, all common chemical fertilizer), and site-specific N management (SSNM, 333 kg N ha-1 yr-1, all common chemical fertilizer) were conducted in the Taihu Lake region with the ‘farmer’s N’ treatment (FN, 510 kg N ha-1 yr-1, all common chemical fertilizer) as a control. Grain yield, plant N uptake (PNU), NUE, and N losses via runoff, leaching, and ammonia volatilization were assessed. In the rice season, the FN treatment had the highest N loss and lowest NUE, which can be attributed to an excessive rate of N application. Treatments of OCN and RCN with a 22% reduced N rate from FN had no significant effect on PNU nor the yield of rice in the 3 yr; however, the NUE was improved and N loss was reduced 20-32%. OCN treatment achieved the highest yield, while SSNM has the lowest N loss and highest NUE due to the lowest N rate. In wheat season, N loss decreased about 28-48% with the continuous reduction of N input, but the yield also declined, with the exception of OCN treatment. N loss through runoff, leaching and ammonia volatilization was positively correlated with the N input rate. When compared with the pure chemical fertilizer treatment of RCN under the same N input, OCN treatment has better NUE, better yield, and lower N loss. 70% of the urea replaced with resin-coated urea had no significant effect on yield and NUE improvement, but decreased the ammonia volatilization loss. Soil

  17. Preliminary tephra-fall records from three lakes in the Anchorage, Alaska area: advances towards a regional tephrochronostratigraphic framework

    NASA Astrophysics Data System (ADS)

    Wallace, K. L.; Kaufman, D. S.; Schiff, C. J.; Kathan, K.; Werner, A.; Hancock, J.; Hagel, L. A.

    2010-12-01

    Sediment cores recovered from three kettle lakes, all within 10 km of Anchorage, Alaska contain a record of tephra fall from major eruptive events of Cook Inlet volcanoes during the past 11250 yr. Prominent tephra layers from multiple cores within each lake were first correlated within each basin using physical properties, major-oxide glass geochemistry, and constrained by bracketing radiocarbon age. Distinct tephra from each lake were then correlated among all three lakes using the same criteria to develop a composite tephrostratigraphic framework for the Anchorage area. Lorraine Lake, the northern-most lake contains 17 distinct tephra layers; Goose Lake, the eastern most lake contains 10 distinct tephra layers; and Little Campbell Lake, to the west, contains 7 distinct tephra layers. Thinner, less-prominent tephra layers, reflecting smaller or more distant eruptions, also occur but are not included as part of this study. Of the 33 tephra layers, only two could be confidently correlated among all three lakes, and four other correlative deposits were recognized in two of the three lakes. The minimum number of unique major tephra-fall events in the Anchorage area is 22 in the past 11200 years, or about 1 event every 500 years. This number underestimates the actual number of eruptions because not attempt was made to locate crypto-tephra. All but perhaps one tephra deposit originated from Cook Inlet volcanoes with the most prolific source being Mount Spurr/Crater Peak, which is accountable for at least 8 deposits. Combining radiocarbon ages to produce an independent age model for each lake is in progress and will aid in confirming correlations and assigning detailed modeled-tephra age and uncertainty to each tephra layer.

  18. Whole-genome sequencing reveals small genomic regions of introgression in an introduced crater lake population of threespine stickleback.

    PubMed

    Yoshida, Kohta; Miyagi, Ryutaro; Mori, Seiichi; Takahashi, Aya; Makino, Takashi; Toyoda, Atsushi; Fujiyama, Asao; Kitano, Jun

    2016-04-01

    Invasive species pose a major threat to biological diversity. Although introduced populations often experience population bottlenecks, some invasive species are thought to be originated from hybridization between multiple populations or species, which can contribute to the maintenance of high genetic diversity. Recent advances in genome sequencing enable us to trace the evolutionary history of invasive species even at whole-genome level and may help to identify the history of past hybridization that may be overlooked by traditional marker-based analysis. Here, we conducted whole-genome sequencing of eight threespine stickleback (Gasterosteus aculeatus) individuals, four from a recently introduced crater lake population and four of the putative source population. We found that both populations have several small genomic regions with high genetic diversity, which resulted from introgression from a closely related species (Gasterosteus nipponicus). The sizes of the regions were too small to be detected with traditional marker-based analysis or even some reduced-representation sequencing methods. Further amplicon sequencing revealed linkage disequilibrium around an introgression site, which suggests the possibility of selective sweep at the introgression site. Thus, interspecies introgression might predate introduction and increase genetic variation in the source population. Whole-genome sequencing of even a small number of individuals can therefore provide higher resolution inference of history of introduced populations. PMID:27069575

  19. Characterization of a novel hepadnavirus in the white sucker (Catostomus commersonii) from the Great Lakes Region of the USA

    USGS Publications Warehouse

    Hahn, Cassidy M.; Iwanowicz, Luke R.; Cornman, Robert S.; Conway, Carla M.; Winton, James R.; Blazer, Vicki S.

    2015-01-01

    The white sucker Catostomus commersonii is a freshwater teleost often utilized as a resident sentinel. Here, we sequenced the full genome of a hepatitis B-like virus that infects white suckers from the Great Lakes Region of the USA. Dideoxysequencing confirmed the white sucker hepatitis B virus (WSHBV) has a circular genome (3542 bp) with the prototypical codon organization of hepadnaviruses. Electron microscopy demonstrated that complete virions of approximately 40 nm were present in the plasma of infected fish. Compared to avi- and orthohepadnaviruses, sequence conservation of the core, polymerase and surface proteins was low and ranged from 16-27% at the amino acid level. An X protein homologue common to the orthohepadnaviruses was not present. The WSHBV genome included an atypical, presumptively non-coding region absent in previously described hepadnaviruses. Phylogenetic analyses confirmed WSHBV as distinct from previously documented hepadnaviruses. The level of divergence in protein sequences between WSHBV other hepadnaviruses, and the identification of an HBV-like sequence in an African cichlid provide evidence that a novel genus of the family Hepadnaviridae may need to be established that includes these hepatitis B-like viruses in fishes. Viral transcription was observed in 9.5% (16 of 169) of white suckers evaluated. The prevalence of hepatic tumors in these fish was 4.9%, of which only 2.4% were positive for both virus and hepatic tumors. These results are not sufficient to draw inferences regarding the association of WSHBV and carcinogenesis in white sucker.

  20. Unified Scaling Law for Earthquakes: Seismic hazard and risk assessment for Himalayas, Lake Baikal, and Central China regions

    NASA Astrophysics Data System (ADS)

    Nekrasova, Anastasia; Kossobokov, Vladimir; Parvez, Imtiyaz; Tao, Xiaxin

    2015-04-01

    The Unified Scaling Law for Earthquakes (USLE), that generalizes the Gutenberg-Richter recurrence relation, has evident implications since any estimate of seismic hazard depends on the size of the territory that is used for investigation, averaging, and extrapolation into the future. Therefore, the hazard may differ dramatically when scaled down to the proportion of the area of interest (e.g. territory occupied by a city) from the enveloping area of investigation. In fact, given the observed patterns of distributed seismic activity the results of multi-scale analysis embedded in USLE approach demonstrate that traditional estimations of seismic hazard and risks for cities and urban agglomerations are usually underestimated. Moreover, the USLE approach provides a significant improvement when compared to the results of probabilistic seismic hazard analysis, e.g. the maps resulted from the Global Seismic Hazard Assessment Project (GSHAP). We apply the USLE approach to evaluating seismic hazard and risks to population of the three territories of different size representing a sub-continental and two different regional scales of analysis, i.e. the Himalayas and surroundings, Lake Baikal, and Central China regions.

  1. Effects of reservoirs on river nitrogen and phosphorus export in the Mississippi and Great Lakes Basins: A regional comparison

    NASA Astrophysics Data System (ADS)

    Powers, S. M.; Tank, J. L.; Robertson, D.

    2013-12-01

    Reservoirs can influence mass transport of anthropogenic nitrogen (N) and phosphorus (P) through rivers, but comparative studies are needed to better understand how reservoir processes vary among landscapes and regions. We compared influences of reservoirs on N and P delivery to tributaries of the Mississippi and Great Lakes Basins, using river monitoring stations that were positioned immediately downstream of reservoir outlets. For a given agricultural intensity (percent of basin classified as cropland), outlet stations (n=115) had lower mean annual flow-weighted concentration for N and P than other stations (n=1085), as well as lower concentration variability. For instance, in the presence of high agriculture (>50% of basin as cropland), reservoir outflow stations had on average 40% lower N and 35% lower P concentration, while the coefficient of variation for both N and P was 30% lower. These aggregate patterns were examined more closely for individual reservoirs of different regions, which fell into two monitoring categories: 1) those which had monitoring stations positioned at the inflow as well as the outflow (n= 23 for TN, n=34 for TP); 2) those which had outflow monitoring stations, as well as an estimate of the expected inflow (from a spatially-referenced regression model). Again, both outflow nutrient concentration and yield (mass per basin area) were usually lower and more stable than the inflow. However, the difference between outflow and inflow varied substantially among reservoirs and regions, including some cases where reservoirs appeared to be net P sources to rivers at the annual time frame. These effects of reservoirs on river N and P are presumably the consequence of reservoir nutrient burial, microbial denitrification, and internal nutrient recycling. Management intended to improve the water quality of rivers and receiving waters would benefit from an improved understanding of reservoir processes, which not only vary among regions, but also could

  2. Use of frequency-volume analyses to estimate regionalized yields and loads of sediment, phosphorus, and polychlorinated biphenyls to lakes Michigan and Superior

    USGS Publications Warehouse

    Robertson, D.M.

    1996-01-01

    In most rivers, transport of various constituents occurs largely during short-term, high-intensity events. A method is described to make regionalized estimates of the long-term average loads of selected streamwater constituents, as well as loads occurring during high-flow events with specified recurrence intervals. This method is used to estimate the load of suspended sediment, total phosphorus, and sediment-borne constituents, such as poly chlorinated biphenyls (PCB's), from all the rivers in the United States that drain into Lake Michigan and Lake Superior whose drainage basins are greater than 325 square kilometers. Statistical comparisons of estimated loads and environmental factors indicate that suspendedsediment loads were primarily affected by river gradient and secondarily affected by the texture of surficial deposits, whereas total phosphorus loadings were primarily affected by the texture of surficial deposits and secondarily affected by river gradient. Total phosphorus loads were highest in rivers entering into the middle to southern part of Lake Michigan, especially rivers in areas draining clay surficial deposits and agricultural areas. During high flow, inputs of phosphorus and suspended sediment from rivers entering the southwestern part of Lake Superior become very important to the total input of these constituents; these rivers have steep gradients and drain surficial deposits with high clay content. The single largest contributor of PCB's during the entire period and during each type of high-flow event was the Fox River, which supplied 46 to 64 percent of the total PCB load to both lakes.

  3. Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife, NT, (Canada) Region.

    PubMed

    Houben, Adam James; D'Onofrio, Rebecca; Kokelj, Steven V; Blais, Jules M

    2016-01-01

    Gold mines in the Yellowknife, NT, region--in particular, the Giant Mine--operated from 1949-99, releasing 237,000 tonnes of waste arsenic trioxide (As2O3) dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing. Additionally, we demonstrate that underlying bedrock is not a significant source for the elevated concentrations in overlying surface waters. Aquatic arsenic (As) concentrations are well above guidelines for drinking water (10 μg/L) and protection for aquatic life (5 μg/L), ranging up to 136 μg/L in lakes within 4 km from the mine, to 2.0 μg/L in lakes 24 km away. High conversion ratios of methyl mercury were shown in lakes near the roaster stack as well, with MeHg concentrations reaching 44% of total mercury. The risk of elevated exposures by these metals is significant, as many lakes used for recreation and fishing near the City of Yellowknife are within this radius of elevated As and methyl Hg concentrations. PMID:27050658

  4. Age constraints for Paleoproterozoic glaciation in the Lake Superior Region: Detrital zircon and hydrothermal xenotime ages for the Chocolay Group, Marquette Range Supergroup

    USGS Publications Warehouse

    Vallini, D.A.; Cannon, W.F.; Schulz, K.J.

    2006-01-01

    A geochronological study of the Chocolay Group at the base of the Paleoproterozoic Marquette Range Supergroup in Michigan, Lake Superior Region, is attempted for the first time, Age data from detrital zircon grains and hydrothermal xenotime from the basal glaciogenic formation, the Enchantment Lake Formation, and the stratigraphically higher Sturgeon Quartzite and its equivalent, the Sunday Quartzite, provide maximum and minimum age constraints for the Chocolay Group. The youngest detrital zircon population in the Enchantment Lake Formation is 2317 ?? 6 Ma; in the Sturgeon Quartzite, it is 2306 ?? 9 Ma, and in the Sunday Quartzite, it is 2647 ?? 5 Ma. The oldest hydrothermal xenotime age in the Enchantment Lake Formation is 2133 ?? 11 Ma; in the Sturgeon Quartzite, it is 2115 ?? 5 Ma, and in the Sunday Quartzite, it is 2207 ?? 5 Ma. The radiometric age data in this study implies the depositional age of the Chocolay Group is constrained to ???2.3-2.2 Ga, which proves its correlation with part of the Huronian Supergroup in the Lake Huron Region, Ontario, and reveals the unconformity that separates the Chocolay Group from the overlying Menominee Group is up to 325 million years in duration. The source(s) of the ??? 2.3 Ga detrital zircon populations in the Enchantment Lake Formation and Sturgeon Quartzite remains an enigma because no known rock units of this age are known in the Michigan area. It is speculated that once widespread volcano-sedimentary cover sequences in Michigan were removed or concealed prior to Chocolay Group deposition. The hydrothermal xenotime ages probably reflect basinal hydrothermal fluid flow associated with the period of extension involving rifting and major dyke formation, that affected the North American provinces between 2.2 and 2.1 Ga. ?? 2006 NRC Canada.

  5. Late Glacial and Holocene environmental history of Wielkopolska region (western Poland) recorded in sediments of Strzeszyńskie Lake and Kierskie Lake

    NASA Astrophysics Data System (ADS)

    Pleskot, Krzysztof; Szczuciński, Witold; Tjallingii, Rik; Makohonienko, Mirosław; Nowaczyk, Norbert; Brauer, Achim

    2016-04-01

    The growing amount of publications concerning reconstructions of Late Glacial and Holocene environment based on analysis of lake sediments gives us robust insight into general patterns of that record. However, it is still challenging to decipher processes and events that occurred on local scale, as they record may be strongly affected by the type, catchment, size and depth of a lake. Therefore in the present study we focus on application of sedimentological and geochemical methods in order to reveal environmental history from two neighbouring lakes located within city of Poznań, Wielkopolska (western Poland). The lake sediments analysis cover Late Glacial and Holocene in case of smaller Strzeszyńskie Lake (SL) and the last 8 ka in deeper Kierskie Lake (KL). The study is based on two 8.5 (SL) and 14 (KL) m long sediment cores, which were described and analyzed in thin sections and on smear slides. The relative chemical composition variations within the cores were measured using an X-ray fluorescence (XRF). Moreover, the cores were measured for magnetic susceptibility and sampled for pollen analysis. The chronology has been established by a AMS 14C dating of bulk samples of lake sediments. To assess the reservoir effect, selected samples were analyzed for soluble and residual carbon fractions. Our results suggest the onset of authigenic sedimentation in SL in Allerød. The sediments from this period are characterized by high organic matter and low carbonate content. This trend changed into opposite at the beginning of the Younger Dryas, while at its termination sediments again became more organic. The transition to Holocene is marked by spread of Betula forest, gradual increase in magnetic susceptibility and Ca content together with decreasing organic matter and clastic input. During Preboreal and Boreal period the relatively stable conditions was noted. Then, ca. 8.5 ka BP, sharp decrease in magnetic susceptibility occurred coincided with deciduous forest

  6. REGIONAL SCALE TREND MONITORING OF INDICATORS OF TROPHIC CONDITION OF LAKES

    EPA Science Inventory

    Society increasingly faces a need to determine whether the condition of its aquatic resources is improving, degrading, or remaining the same on statewide, regional, and national scales. he U.S.EPA has proposed a sample survey design to answer questions about the ecological condit...

  7. Climate change impacts on soil erosion in the Great Lakes Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying changes in potential soil erosion under projections of changing climate is important for the sustainable management of land resources, especially for regions dominated by agricultural land use, as soil loss estimates will be helpful in identifying areas susceptible to erosion, targeting ...

  8. REGIONAL-SCALE FISH ECOLOGY IN NORTHEASTERN USA LAKES USING A PROBABILITY-BASED SURVEY DESIGN

    EPA Science Inventory

    Historically, most fish ecology has been done at local scales. As these data accumulate, the need to set this knowledge into landscape, regional, and historical context grows. There are important broad-scale issues (e.g., non-point source pollution, biodiversity loss, alien spe...

  9. Fungicide sensitivity testing of Cercospora beticola from sugarbeet in the Great Lakes Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cercospora leaf spot (CLS), caused by Cercospora beticola (Sacc.), is the most serious foliar disease of sugarbeet (Beta vulgaris L.) worldwide. CLS is problematic in most sugarbeet growing regions and can cause significant economic losses due to decreases in both yield and sugar purity in the harve...

  10. The impact of climate change on soil erosion in Great Lakes Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying changes in potential soil erosion under projections of changing climate is important for the sustainable management of land resources, especially for regions dominated by agricultural land use. One of the expected changes to climate in the future is an increase in the frequency and inten...

  11. 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. ...

  12. REGIONAL PATTERNS AND LOCAL VARIABILITY OF DRY AND OCCULT DEPOSITION STRONGLY INFLUENCE SULFATE CONCENTRATIONS IN MAINE LAKES

    EPA Science Inventory

    There is great uncertainty and large cost in making dry deposition measurements. e present evidence based on wet deposition, evapotranspiration, S storage in lake sediments, and sulfate concentrations in lakes and streams in Nllaine that the dry deposition flux of sulfur to drain...

  13. Distribution, sources, and risks of polycyclic aromatic hydrocarbons in the surface sediments from 28 lakes in the middle and lower reaches of the Yangtze River region, China.

    PubMed

    Li, Shanying; Tao, Yuqiang; Yao, Shuchun; Xue, Bin

    2016-03-01

    As the largest polycyclic aromatic hydrocarbons (PAHs) emission country, China is suffering from severe PAHs pollution. Twenty-eight lakes in the middle and lower reaches of the Yangtze River region (MLYR), where numerous lakes are located in and play very important roles in the development of the local economy and society, were selected to investigate the levels and sources of the PAHs in this region and the related influence factors. Concentrations of the 16 PAHs (∑PAHs) in the sediments ranged from 221.0 to 2418.8 ng g(-1) (dry weight). The mean ∑PAHs was higher in the lower reaches than in the middle reaches. ∑PAHs in the sediments was positively correlated with the local gross domestic product (GDP), which implies that GDP was the key factor to affect the PAHs level in the sediments of study area. According to the composition of 16 PAHs, the 28 lakes were grouped into 3 clusters. Major PAHs sources for the three types of lakes were significantly different, which were biomass combustion, coal combustion, and vehicle/coal source, respectively. The total toxic benzo(a)pyrene equivalent (TEQ(carc)) of the carcinogenic PAHs in the sediments varied from 12.9 to 472.9 ng TEQ(carc) g(-1). Benzo(a)pyrene (BaP) and dibenzo(a,h)anthracene (DaA) were the two main contributors to total TEQ(carc). PMID:26541148

  14. Classification of natural ponds and lakes in the glaciated prairie region

    USGS Publications Warehouse

    Stewart, Robert E.; Kantrud, Harold A.

    1971-01-01

    The wetland classification system for the United States adopted by the Bureau of Sport Fisheries and Wildlife in 1953 is described by Martin et al (1953) and by Shaw and Fredine (1956).  That classification has been followed by many biologists in recent years and is especially useful in categorizing in a general manner the wetlands throughout the country over a span of years.  It has become apparent, however, that for research and intensive management a dynamic classification system that more precisely reflects seasonal, regional, and local variations in the environment is needed.  To establish a detailed wetland classification system for all of  North America will require intensive ecological investigation of wetlands in each of the major biogeographical regions.

  15. Simulated Sensitivity of Seasonal Ozone Exposure in the Great Lakes Region to Changes in Anthropogenic Emissions in the Presence of Interannual Variability

    SciTech Connect

    Fast, Jerome D.; Heilman, Warren E.

    2005-09-01

    A coupled meteorological and chemical modeling system with a 12-km horizontal grid spacing was used to simulate the evolution of ozone over the Great Lakes region between May and September of 1999 and 2001. Model performance was evaluated using operational surface and upper-air meteorological measurements and surface ozone data. The overall temporal and spatial variations in hourly ozone concentrations and ozone exposure from control simulations agreed reasonably well with the observations at most locations. The simulated ozone exposure was higher during the summer of 1999 than during 2001, similar to the observations. The emission projection simulation that employed the meteorological conditions of 1999 and increased anthropogenic emissions projected for the year 2020 produced increases in ozone exceeding 80 ppb over the lower peninsula of Michigan, the eastern half of the upper peninsula of Michigan, and over Ontario just north of Lake Superior and Lake Huron. Relatively large increases in ozone exceeding 60 ppb were also produced over agricultural regions. Despite the projected increase in anthropogenic emissions for the year 2020, increases in ozone exceeding 60 ppb occurred only over the lake surfaces and in central Michigan when the meteorological conditions of the summer of 2001 were applied. The meteorological conditions during the summer of 2001 were not as favorable for ozone production and did not result in increased ozone. For both summers, increases in anthropogenic emissions projected for the year 2020 decreased ozone exposure in the immediate vicinity of the largest metropolitan areas. The simulated ozone from this study will be used in the near future as input to biological models to assess the response of ozone-sensitive tree species to current and future ozone levels in the Great Lakes region.

  16. Indicator Development for Potential Presence of Schistosomiasis Japonicum's Vector in Lake and Marshland Regions- A Case Study of Poyang Lake, Jiangxi Province, P.R. China

    NASA Astrophysics Data System (ADS)

    Marie, Tiphanie; Yesou, Herve; Huber, Claire; De Fraipont, Paul; Uribe, Carlos; Lacaux, Jean-Pierre; Lafaye, Murielle; Lai, Xijun; Desnos, Yves-Louis

    2013-01-01

    Earth observation data and bibliography on environmental parameters were used for mapping Oncomelania hupensis distribution, the Schistosomiasis japonicum’s intermediate host snail, within Poyang Lake (Jiangxi Province, P.R. China). Areas suitable for the development of O. hupensis, the vector of schistosomiasis, were derived from submersion time parameters and vegetation community indicators. ENVISAT time series data acquired from 2000 to 2009 were used for submersion times mapping, and 5 Beijing-1 data acquired during the dry season between 2006 and 2008 were used to map suitable vegetation for vector development. Yearly maps obtained indicate four principally potential endemic areas: the Gan Delta, the bank of the Fu He River, the Dalianzi Hu sector and the Poyang Lake Nature Reserve. Monthly maps from December 2005 to December 2008 show the dynamic of potential O. hupensis presence areas.

  17. Public health assessment for Onondaga Lake, Syracuse, Onondaga County, New York, Region 2. Cerclis No. NYD986913580. Final report

    SciTech Connect

    1995-07-24

    The Onondaga Lake site is described as Onondaga lake and any source that may be contributing to its contamination (e.g., hazardous waste sites discharging contaminants directly or indirectly via surface or groundwater into Ononaga Lake). The site is contaminated with many chemicals, including mercury, polychlorinated biphenyls (PCBs), petroleum hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs). Based on the information reviewed, the Onondaga Lake site is a public health hazard. Fish from the site are contaminated with mercury and PCBs at levels which have a high risk of adverse health effects. The presence of fecal bacteria is an indicator of potential contamination by other microorganisms that can produce disease. Fecal bacteria contamination of the lake poses a potential health hazard to recreational users, particularly swimmers.

  18. The impact of climate and environmental processes on vegetation pattern in the Czechowskie lake catchment Czechowo Region (Northern Tuchola Pinewoods) during the Younger Dryas cooling

    NASA Astrophysics Data System (ADS)

    Noryśkiewicz, Agnieszka Maria; Kramkowski, Mateusz; Słowiński, Michał; Zawiska, Izabela; Lutyńska, Monika; Błaszkiewicz, Mirosław; Brauer, Achim

    2014-05-01

    Czechowskie lake is located in the northern part of the Tuchola Pinewoods District (Northern Poland) in a young glacial landscape. At present, the majority of the area is forested or used for agricultural purposes, but among them a high amount of basins filled with biogenic sediments are present. This area is very suitable for the postglacial vegetation development investigation because of the LST ash and laminated sediments which we found in the Trzechowskie palaeolake and Czechowskie Lake (Wulf et. all 2013). The aim of the research was to reconstruct the past landscape and vegetation response to Younger Dryas cooling and we present the results of the palinological analysis done for 6 core of biogenic sediments. Our main objective was to determine whether local factors such as topography and soil cover have a significant impact on the vegetation, eutrophy and sedimentation rate at this time. In the lake Czechowskie lake catchment we have six cores that cover postglacial succession (Lake Czechowskie small basin - profile JC-12-s; Lake Czechowskiego terrace - profile TK; Lake Czechowskie vicinity - profile "Oko and Cz/80; Trzechowskie paleolake - profile T/trz; Valley between paleolake Trzechowskie and Lake Czechowskie - profile DTCZ-4). The paleoecological research carried out involved an analysis of pollen, macrofossils, Cladocera, diatom, loss-on-ignition and CaCO3 content. The results show, that the dominant plant communities during the Youngers Dryas in the region nearby Lake Czechowskie are heliophytes xeric herb vegetation with juniper (Juniperus communis) shrubs and birch (Betula) and pine (Pinus sylvestris). In the pollen diagrams there was the difference noted in the participation of the dominant pollen, the juniper pollen was always high but varied from 18 to 37%, birch average pollen share was between 17-27%. The thickness and type of the sediment accumulated in Younger Dryas in the presented profiles differs significantly. In the profiles which

  19. The Relationship between Eating and Lifestyle Habits and Cancer in Van Lake Region: Another Endemic Region for Esophageal and Gastric Cancers

    PubMed Central

    Celik, Sebahattin; Yılmaz, E. Murat; Özden, Ferhat; Kotan, Cetin

    2015-01-01

    Purpose. To examine the relationship between esophageal and gastric cancers commonly seen in Van Lake region and the traditional eating habits of the geography. Materials and Methods. Esophageal and gastric cancer cases, who underwent surgery between January 1, 2012, and December 31, 2013, were examined. Pathology reports of the patients and presence of Helicobacter pylori (HP) were recorded. Surveys were filled by face to face meeting or telephone call. Control group was created with randomly selected individuals without any cancer diagnosis having age, gender, and socioeconomic characteristics similar to patient group. All data were analyzed using SAS.9.3 statistical programme. Results. Compared with the control group, herby cheese consumption (a component of eating habits) and smoking were significantly higher in the patient group (P < 0.001). Tandoor exposure is compared in terms of female gender, and significant difference was found between the groups (P = 0.0013). As a result of the analysis with logistic regression more than 150 gr of herby cheese consumption per day was found to increase the cancer risk (odds ratio 1.017; 95% CI: 1.012–1.022). Conclusion. A high consumption of herby cheese, cooking bread on tandoor, and heavy smoking were seen to be important risk factors for esophageal and gastric cancers. PMID:25648523

  20. Assessment of ERTS-1 imagery as a tool for regional geological analysis in New York State. [Lake Ontario

    NASA Technical Reports Server (NTRS)

    Isachsen, Y. W. (Principal Investigator); Fakundiny, R. H.; Forster, S. W.

    1974-01-01

    The author has identified the following significant results. Linear anomalies dominate the new geological information derived from ERTS-1 imagery, total lengths now exceeding 26,500 km. Maxima on rose diagrams for ERTS-1 anomalies correspond well with those for mapped faults and topographic lineaments. Multi-scale analysis of linears shows that single topographic linears at 1:2,500,000 may become dashed linears at 1:1,000,000 aligned zones of shorter parallel, en echelon, or conjugate linears at 1:5000,000, and shorter linears lacking any conspicuous zonal alignment at 1:250,000. Field work in the Catskills suggests that the prominent new NNE lineaments may be surface manifestations of dip slip faulting in the basement, and that it may become possible to map major joint sets over extensive plateau regions directly on the imagery. Most circular features found were explained away by U-2 airfoto analysis but several remain as anomalies. Visible glacial features include individual drumlins, drumlinoids, eskers, ice-marginal drainage channels, glacial lake shorelines, sand plains, and end moraines.

  1. Polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDE) air concentrations in the Lake Ontario region: Trends and potential sources

    NASA Astrophysics Data System (ADS)

    Choi, Hyun-Deok; Pagano, James J.; Milligan, Michael S.; Hopke, Philip K.; Skubis, Steven; Holsen, Thomas M.

    2010-08-01

    Airborne particle and gas samples were collected approx every 12 days from April 2002 to June 2006 at the Sterling Nature Center located near the southeast corner of Lake Ontario. These samples were analyzed for polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDE). Clausius-Clapeyron (C-C) regression analyses of PCBs and DDE yielded moderate correlations ( r 2 = 0.54, p < 0.001; r 2 = 0.74, p < 0.001, respectively) indicating that much of the variations in concentrations can be explained by temperature. Back trajectory analysis indicated that the most important factors driving unusually high PCB partial pressures relative to those predicted by the C-C regression were slow wind speeds and winds generally from the southwest. This combination, which occurred frequently in 2004, increased contact of the air with contaminated upwind surfaces with minimum dilution. Hybrid receptor modeling (Potential Source Contribution Function (PSCF)) results for the total PCBs identified the midwestern US region that contains the urban areas of southern Indiana (IN), southwestern Ohio (OH), and northern Kentucky (KY) having the highest PSCF values. In general urban areas like Chicago (IL), Detroit (MI), Cleveland (OH), St. Louis (MO), and Nashville (TN) also had significant possibilities. In contrast, the PSCF modeling for DDE identified northern Alabama as the area with the highest probability where DDT was applied to cotton fields.

  2. Hydroacoustic estimation of zooplankton biomass at two shoal complexes in the Apostle Islands Region of Lake Superior

    USGS Publications Warehouse

    Holbrook, B.V.; Hrabik, T.R.; Branstrator, D.K.; Yule, D.L.; Stockwell, J.D.

    2006-01-01

    Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with zooplankton dry weight biomass estimated from net tows. The relationship between zooplankton dry weight and backscatter was significant (p < 0.001) and explained 76% of the variability in the dry weight data. We applied this regression to hydroacoustic data collected monthly in 2003 and 2004 at two shoals in the Apostle Island Region of Lake Superior. After applying the regression model to convert hydroacoustic backscatter to zooplankton dry weight biomass, we used geostatistics to analyze the mean and variance, and ordinary kriging to create spatial zooplankton distribution maps. The mean zooplankton dry weight biomass estimates from plankton net tows and hydroacoustics were not significantly different (p = 0.19) but the hydroacoustic data had a significantly lower coefficient of variation (p < 0.001). The maps of zooplankton distribution illustrated spatial trends in zooplankton dry weight biomass that were not discernable from the overall means.

  3. Invasion of Nostocales (cyanobacteria) to Subtropical and Temperate Freshwater Lakes – Physiological, Regional, and Global Driving Forces

    PubMed Central

    Sukenik, Assaf; Hadas, Ora; Kaplan, Aaron; Quesada, Antonio

    2012-01-01

    Similar to the increased number of studies on invasive plants and animals in terrestrial and aquatic ecosystems, many reports were recently published on the invasion of Nostocales (cyanobacteria) to freshwater environments worldwide. Invasion and proliferation of Nostocales in new habitats have the potential to significantly alter the structure of the native community and to modify ecosystem functioning. But most importantly, they influence the water quality due to a variety of toxic compounds that some species produce. Therefore a special attention was given to the invasion and persistence of toxic cyanobacteria in many aquatic ecosystems. Here we summarize the currently published records on the invasion of two Nostocales genera, Cylindrospermopsis and Aphanizomenon, to lakes and water reservoirs in subtropical and temperate zones. These invading species possess traits thought to be common to many invasive organisms: high growth rate, high resource utilization efficiency and overall superior competitive abilities over native species when local conditions vary. Assuming that dispersion routes of cyanobacteria have not been changed much in recent decades, their recent establishment and proliferation in new habitats indicate changes in the environment under which they can exploit their physiological advantage over the native phytoplankton population. In many cases, global warming was identified as the major driving force for the invasion of Nostocales. Due to this uncontrollable trend, invasive Nostocales species are expected to maintain their presence in new habitats and further expand to new environments. In other cases, regional changes in nutrient loads and in biotic conditions were attributed to the invasion events. PMID:22408640

  4. Environmental change and seasonal behavior of mastodons in the Great Lakes region inferred from stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Metcalfe, Jessica Z.; Longstaffe, Fred J.

    2014-09-01

    We investigate seasonal variations in the diet and drinking water of four Great Lakes mastodon (Mammut americanum) specimens using stable isotope analysis of serially sampled inner-enamel bioapatite structural carbonate (δ13Csc, δ18Osc), and previously published bulk analyses. Isotopic analyses and thin section measurements showed that mastodon tooth enamel extension rates (~ 12-4 mm/yr, decreasing toward the cervix) were lower than those of mammoths or modern elephants. Mastodons had distinct and highly regular seasonal variations in δ13Csc and δ18Osc, which we interpret in the context of local glacial history and vegetation changes. Seasonal variations in δ18O were large but variations in δ13C were small, and may have been obscured if coarser sampling methods than our inner-enamel sampling approach were used. Thus, our approach may be particularly useful for understanding relatively small seasonal changes in δ13C within C3 environments. The seasonal patterns, though not entirely conclusive, suggest that the Ontario mastodons did not migrate over very long distances. Rather, the climate and seasonal dietary patterns of mastodons within the region changed over time, from ~ 12,400 to 10,400 14C yr BP (~ 15,000 - 12,000 cal yr BP). Insights gained using these methods can contribute to a better understanding of megafaunal extinctions and Paleoamerican lifeways.

  5. Location of active transmission sites of Schistosoma japonicum in lake and marshland regions in China.

    PubMed

    Zhang, Z J; Carpenter, T E; Lynn, H S; Chen, Y; Bivand, R; Clark, A B; Hui, F M; Peng, W X; Zhou, Y B; Zhao, G M; Jiang, Q W

    2009-06-01

    Schistosomiasis control in China has, in general, been very successful during the past several decades. However, the rebounding of the epidemic situation in some areas in recent years raises concerns about a sustainable control strategy of which locating active transmission sites (ATS) is a necessary first step. This study presents a systematic approach for locating schistosomiasis ATS by combining the approaches of identifying high risk regions for schisotosmiasis and extracting snail habitats. Environmental, topographical, and human behavioural factors were included in the model. Four significant high-risk regions were detected and 6 ATS were located. We used the normalized difference water index (NDWI) combined with the normalized difference vegetation index (NDVI) to extract snail habitats, and the pointwise 'P-value surface' approach to test statistical significance of predicted disease risk. We found complicated non-linear relationships between predictors and schistosomiasis risk, which might result in serious biases if data were not properly treated. We also found that the associations were related to spatial scales, indicating that a well-designed series of studies were needed to relate the disease risk with predictors across various study scales. Our approach provides a useful tool, especially in the field of vector-borne or environment-related diseases. PMID:19416552

  6. Two millennia of torrential activity reconstructed from alpine lake sediments: towards regional patterns of extreme precipitation changes

    NASA Astrophysics Data System (ADS)

    Wilhelm, B.; Arnaud, F.; Giguet-Covex, C.; Sabatier, P.; Crouzet, C.; Delannoy, J. J.

    2012-04-01

    In mountain areas extreme precipitation events trigger torrential floods, characterized by a sudden and intense rise of discharge causing large human and economic losses. Their frequency and/or intensity are expected to increase in the context of global warming. However, the relationship between such events and climate changes remains difficult to assess. Long-term geological records of intense events could enable to extend documented records beyond the observational data for a better understanding of local to regional flood hazard patterns in relation to past climatic changes and hence improving predictive models. In this context, lake sediment records appear a relevant archive as they are continuous records in which the identification of high-energy sediment layers allows to reconstruct flood calendar. In addition, the flood intensity can be reconstructed from the coarse fraction of each flood layer. Frequency and intensity of past torrential floods were thus reconstructed from four high-elevation lake records of the French Alps, in the framework of Pygmalion research program. Studied sites were selected along a north-south transect over this region to investigate the flooding responses to different climatic influences (westerlies in the north and Mediterranean influences in the south). High-resolution geochemical and sedimentological analyses were undertaken for an exhaustive identification of flood layers and several dating methods (short-lived radionuclides, 14C, correlation with historic events, paleomagnetism) were combined to reduce age uncertainties as much as possible. Over the entire French Alps, the torrential-flood frequency increases at a secular timescale during the cold period of the Little Ice Age (LIA; 1300-1900 AD). This increase seems in agreement with a regional high wetness, already described in the literature, possibly related to an increase in cyclonic activity. Superimposed to this secular trend, a pluri-decadal variability appears at

  7. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

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

    2003-01-01

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

  8. Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China

    PubMed Central

    2014-01-01

    Background Owing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails. Methods Moisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails. Results A total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively. Conclusion The results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6

  9. GRACE water storage estimates for the Middle East and other regions with significant reservoir and lake storage

    NASA Astrophysics Data System (ADS)

    Longuevergne, L.; Wilson, C. R.; Scanlon, B. R.; Crétaux, J. F.

    2012-10-01

    While GRACE (Gravity Recovery and Climate Experiment) satellites are increasingly being used to monitor water storage changes globally, the impact of spatial distribution of water storage within a basin is generally ignored but may be substantial. In many basins, water may be stored in reservoirs, lakes, flooded areas, small aquifer systems, and other localized regions with sizes typically below GRACE resolution. The objective of this study was to assess the impact of non-uniform water storage distribution on GRACE estimates as basin-wide averages, focusing on surface water reservoirs. Analysis included numerical experiments testing the effect of mass size and position within a basin, and application to the Lower Nile (Lake Nasser) and Tigri-Euphrates (TE) basins as examples. Numerical experiments show that by assuming uniform mass distribution, GRACE estimates may under- or over-estimate basin-average water storage by up to a factor of two, depending on reservoir location and extent. Although their spatial extent may be unresolved by GRACE, reservoir storage may dominate in some basins. For example, it accounts for 95% of seasonal variations in the Lower Nile and 10% in the TE basins. Because reservoirs are used to mitigate droughts and buffer against climate extremes, their influence on interannual time scales can be large, for example accounting for 50% of total water storage decline during the 2007-2009 drought in the TE basin. Effects on GRACE estimates are not easily accounted for via simple multiplicative scaling, but in many cases independent information may be available to improve estimates. Accurate estimation of the reservoir contribution is critical, especially when separating groundwater from GRACE total water storage changes. Because the influence of spatially concentrated water storage - and more generally water distribution - is significant, GRACE estimates will be improved when it is possible to combine independent spatial distribution information

  10. Analysis of regional rainfall-runoff parameters for the Lake Michigan Diversion hydrological modeling

    USGS Publications Warehouse

    Soong, David T.; Over, Thomas M.

    2015-01-01

    Recalibration of the HSPF parameters to the updated inputs and land covers was completed on two representative watershed models selected from the nine by using a manual method (HSPEXP) and an automatic method (PEST). The objective of the recalibration was to develop a regional parameter set that improves the accuracy in runoff volume prediction for the nine study watersheds. Knowledge about flow and watershed characteristics plays a vital role for validating the calibration in both manual and automatic methods. The best performing parameter set was determined by the automatic calibration method on a two-watershed model. Applying this newly determined parameter set to the nine watersheds for runoff volume simulation resulted in “very good” ratings in five watersheds, an improvement as compared to “very good” ratings achieved for three watersheds by the North Branch parameter set.

  11. Peak discharge estimates of glacial-lake outburst floods and ``normal'' climatic floods in the Mount Everest region, Nepal

    NASA Astrophysics Data System (ADS)

    Cenderelli, Daniel A.; Wohl, Ellen E.

    2001-09-01

    Glacial-lake outburst floods (GLOFs) in the Mount Everest region of Nepal on 3 September 1977 and 4 August 1985 dramatically modified channels and valleys in the region by eroding, transporting, and depositing large quantities of sediment for tens of kilometers along their flood routes. Prior to this research, the GLOF discharges had not been determined and the hydrology of "normal" climatic floods (SHFFs: seasonal high flow floods) was not known. A one-dimensional step-backwater flow model was utilized, in conjunction with paleostage indicators, to estimate the peak discharges of the GLOFs and SHFFs and to reconstruct the hydrology and hydraulic conditions of the GLOFs at 10 reaches and SHFFs at 18 reaches. The most reliable GLOF and SHFF peak discharge estimates were upstream from constrictions where there was critical-depth control. The peak discharge of the 1977 GLOF at 8.6 km from the breached moraine was approximately 1900 m 3/s. At 7.1 km downstream from the breached moraine, the 1985 GLOF discharge was estimated at 2350 m 3/s. At 27 km downstream from the breached moraine, the 1985 GLOF attenuated to an estimated discharge of 1375 m 3/s. The peak discharges of SHFFs ranged from 7 to 205 m 3/s and were positively correlated with increasing drainage area. The GLOF discharges were 7 to 60 times greater than the SHFF discharges with the greatest ratios occurring near the breached moraines. The downstream decline in the ratio between the GLOF discharge and SHFF discharge is the result of the downstream attenuation of the GLOF and the increased discharge of the SHFF because of increased contributing drainage area and the increased effects of monsoonal precipitation at lower elevations.

  12. Synchronous climate-driven regime shifts at the onset of the Holocene inferred from diatom records in lakes of the Greater Yellowstone region

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Stone, J.; Fritz, S. C.

    2013-12-01

    Diatom records covering the late-glacial and early Holocene periods were recovered from three lakes in different areas of Yellowstone National Park to investigate the impacts of large-scale climatic change on aquatic ecosystem evolution following deglaciation. All lakes show synchronous diatom community shifts from the dominance of tychoplanktic Fragilaria species to benthic species in the interval of 11,300-11500 cal yr BP, indicating a regional decrease in effective moisture. The synchroneity of changes in diatom community structure suggests the influence of overlying large-scale climatic change on lacustrine ecosystems. A major shift in the same interval also is evident in other proxy records, such as pollen and charcoal, throughout the Yellowstone region at the late-glacial/early-Holocene transition. This suggests that the summer insolation maximum induced a widespread and rapid reorganization of ecosystem structure and function.

  13. Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002-2008

    USGS Publications Warehouse

    Risch, Martin R.; Gay, David A.; Fowler, Kathleen K.; Keeler, Gerard J.; Backus, Sean M.; Blanchard, Pierrette; Barres, James A.; Dvonch, J. Timothy

    2012-01-01

    Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002-2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002-2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation.

  14. Modeling the Dynamics of the Great Salt Lake as an Integrator of Regional Hydrologic and Climate Processes?

    NASA Astrophysics Data System (ADS)

    Mohammed, I. N.; Tarboton, D. G.

    2005-12-01

    The Great Salt Lake (GSL), Utah, is the fourth largest, perennial, terminal lake in the world. The Great Salt Lake (GSL) level fluctuates due to the balance between inflows and outflows. These fluctuations are of interest whether they are high (flooding hazards) or low (economic impacts). Inflows are due to streamflow, primarily from the Bear River (54%), Weber River (18%) and Jordan/Provo River (28%) systems. Inflows also include precipitation directly on the lake and groundwater both from the East and West sides. The only outflow is evaporation that is controlled by the climate and area of the lake that changes with level. The GSL reached historic high levels above 1284 m in 1873 and 1986. A historic low at 1278 m occurred in 1963. These fluctuations represent the integrated effect of climate and hydrologic processes as well as the dynamic interaction between lake volume, area and salinity that impact evaporation from the lake. The topographic area-volume relationship in the GSL plays a role in the system dynamics because area is a control on the evaporation outflux. This paper examines the relationships between Basin climate (precipitation and temperature), Inflows to the lake (primarily streamflow) and outflows (evaporation). The role played by the topographic elevation-area-volume relationship on lake dynamics and the correspondence between modes in volume and area distributions and peaks in the area-volume derivative was examined. We derived, using a steady state approximation, the relationship between distributions of lake volume and lake area and the area-volume derivative from the topography/bathymetry. This analysis showed that both the topography/bathymetry and multimodality in the area distribution are required to explain the observed multimodality in the volume distribution. We also separated lake volume changes into increases in the spring (due to spring runoff) and declines in the fall (due to evaporation) and then related these volume changes to

  15. The Lake Arthur complex, Jefferson Davis and Vermilion Parishes, Louisiana: How it fits into the regional depositional framework of the Camerina A to Miogypsinoides A interval

    SciTech Connect

    Smith, N.E. )

    1990-09-01

    The Lake Arthur Complex is one of the many normal mega-sized structural features that fit into the normal South Louisiana regional framework when completely studied and understood. To explain this mega-feature requires an understanding of the regional structure and of the stratigraphic depositional patterns of each of the major paleontological sequences from the older Bolivina mexicana through the younger Discorbis intervals, covering sediments of middle Oligocene age to the younger early Miocene age. The Lake Arthur Complex encompasses six producing field areas as recognized by the Louisiana Department of Conservation. These fields produce from multiple sands ranging in age from middle Oligocene through early Miocene. The productive areas are related to a combination of their structural relationship to the overall complex, the stratigraphic depositional patterns of the producing sands as related to regional depositional faulting, and the stratigraphic depositional patterns of the producing sands related to the growth history of this Complex. Each of these variables, or a combination of these variables, has a significant controlling effect on the individual producing areas within the Complex. One of the more significant producing intervals of the Lake Arthur Complex is the sand packages in the Camerina A to Miogypsinoides A middle Oligocene sediments. Ultimately the Lake Arthur Complex may produce in excess of 5 tcf of gas with the Camerina A to Miogypsinoides A responsible for approximately 75% of the estimated production. Each of the significant Camerina A to Miogypsinoides A producing areas in the overall complex is discussed structurally and stratigraphically, including the relationship to the overall regional depositional framework and history of the Camerina A-Miogypsinoides A stratigraphic interval.

  16. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

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

  17. Variations in sediment sources and yields in the Finger Lakes and Catskills regions of New York

    NASA Astrophysics Data System (ADS)

    Nagle, Gregory N.; Fahey, Timothy J.; Ritchie, Jerry C.; Woodbury, Peter B.

    2007-03-01

    The proportional contributions of stream bank and surface sources to fine sediment loads in watersheds in New York State were quantified with uncertainty analysis. Eroding streamside glacial drift, including glaciolacustrine deposits, were examined to help explain variations in the proportional contributions made by bank erosion. Sediment sources were quantified by comparing concentrations of the bomb-derived radionuclide 137Cs in fluvial sediment with sediment from potential source areas such as agricultural soils, forest soils and stream banks.To compare sediment sources in streams containing abundant deposits of fine-grained glacial drift with watersheds that lacked moderate or extensive streamside deposits, samples were taken from 15 watersheds in the region. The mean contribution of bank erosion to sediment loads in the six streams with glaciolacustrine deposits was 60% (range 46-76%). The proportional contribution of bank erosion was also important in one stream lacking glaciolacustrine deposits (57%) but was less important in the remainder, with contributions ranging from 0 to 46%. Data from this study on the varying contributions of bank erosion and data from past studies of sediment yield in 15 watersheds of New York State suggest that eroding streamside glacial deposits dominate sediment yield in many watersheds. In other watersheds, past impacts to streams, such as channelization, have also resulted in high levels of bank erosion. Copyright

  18. [Relationship between landscape pattern and river water quality in Wujingang region, Taihu Lake watershed].

    PubMed

    Zhang, Da-wei; Li, Yang-fan; Sun, Xiang; Zhang, Fang-shan; Zhu, Hong-xing; Liu, Yi; Zhang, Ying; Zhuang, Min; Zhu, Xiao-dong

    2010-08-01

    Wujingang region was taken as the study area to explore the relationship between landscape pattern and river water quality. Remote sensing image was interpreted and buffer zones were constructed, and then landscape patterns characterized by land-use patterns and five selected landscape metrics including Number of patches (NP), Area-weighted mean patch fractal dimension (FRAC _AM), Shannon's diversity index (SHDI), Shannon' s evenness index (SHEI), Contagion index (CONTAG) in each buffer zone were obtained. By employing the correlation analysis between the landscape pattern and river water quality, the results indicated that the river water quality was influenced by landscape pattern. The percentage of built-up area was positively related with water quality indicators, demonstrating that the percentage of built-up area was one of the key factors affecting the river water quality, while the percentage of cultivated land showed a negative relationship. Furthermore, the relationships between the selected five landscape metrics and water quality were also revealed. SHDI and SHEI were significantly positively related with water quality indicators, while CONTAG showed the opposite relationship. PMID:21090292

  19. 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.

  20. The Interdependence of Lake Ice and Climate in Central North America. [correlation between freeze/than cycles of lakes and regional weather variations

    NASA Technical Reports Server (NTRS)

    Jelacic, A. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. A comparison of lake freeze transition zone migration with the movement of large pressure centers reveals the following consistencies: (1) polar continental cyclones originate within and/or travel along the trend of the transition zone; (2) polar continental anticyclones fail to cross the transition zone; (3) polar outbreak anticyclones pass through the transition zone, apparently unaffected. In addition, storm centers associated with the transition zone undergo significant intensification manifest by a deepening of the pressure through and increased precipitation outside the zone.

  1. Downscaling precipitation in the Sahara-Sahelian region during the Holocene in order to decipher the paleo-variations of Lake Chad

    NASA Astrophysics Data System (ADS)

    Contoux, Camille; Bondeau, Alberte; Barrier, Nicolas; Sylvestre, Florence

    2016-04-01

    In order to understand the paleo-variability of Saharo-Sahelian paleoprecipitation, which is recorded in the sediments of Lake Chad situated in central Sahel, we use a modelling chain going from global climate to basin-scale hydrological model. Namely, climate model outputs for the Holocene, starting with the mid-Holocene (6ka) available from the IPSL-CM5 global climate model are statistically downscaled with the General Additive Model approach (Levavasseur et al., 2011), then used to feed the LPJmL model (Bondeau et al., 2007) which calculates the equilibrium vegetation and runoff. Climate and runoff are then given to the dynamic routing scheme HYDRA (Coe et al., 2000) in order to calculate the paleo river network and paleo extent of Lake Chad. The results at each step are compared with reconstructions derived from continental proxies on the regional scale in order to assess the robustness of the results. For the mid-Holocene, the downscaled precipitation matches very well precipitation estimations derived from lacustrine pollen data. For the historical period, the LPJmL simulated runoff averaged over the Chad basin depicts the same trend than observations of Lake Chad water level, but the absolute water level is overestimated in HYDRA, which can be attributed to humid biases both in LPJmL and HYDRA. Finally, we will investigate the relative changes in river network and Lake Chad extent between the present and the mid-Holocene.

  2. Diatoms from Lake Kushu: A pilot study to test the potential of a Late Quaternary palaeoenvironmental archive from Rebun Island (Hokkaido Region, Japan)

    NASA Astrophysics Data System (ADS)

    Schmidt, Mareike; Tarasov, Pavel E.; Hoelzmann, Philipp; Meyer, Hanno; Leipe, Christian

    2016-05-01

    Rebun Island is a key research area for the Baikal-Hokkaido Archaeology Project to better understand the dynamics of the Neolithic hunter-gatherers in the NW Pacific region. Hence, the ca. 19.5 m sediment core RK12 spanning the last ca. 16.6 cal. kyr BP was obtained from Lake Kushu. Our aim is to test its potential as a high-resolution multi-proxy archive. Here, we used diatoms to investigate the modern ecosystem of Lake Kushu and its surrounding area on Rebun Island and of Hime-numa Pond on Rishiri Island and selected core samples for comparison. Modern diatom and stable isotope analyses show well-mixed freshwater bodies with eutrophic, alkaline conditions. The fossil diatom and geochemical sediment analyses display three phases that represent major changes in the lake development: (i) a marshy phase (ca. 16.6-10 cal. kyr BP); (ii) a brackish water lagoon phase (ca. 10-6.6 cal. kyr BP); and (iii) a freshwater lake phase (since ca. 6.6 cal. kyr BP). This shows the major role of the post-glacial climate amelioration, global sea-level rise and marine transgression in the development of this landscape. Further analyses will provide a palaeolimnological record at (sub-)decadal resolution that will facilitate the interpretation of the hunter-gatherer dynamics.

  3. Adapting to Climate Change in the Great Lakes Region: The Wisconsin Initiative on Climate Change Impacts

    NASA Astrophysics Data System (ADS)

    Vimont, D.; Liebl, D.

    2012-12-01

    The mission of the Wisconsin Initiative on Climate Change Impacts (WICCI; http://www.wicci.wisc.edu) is to assess the impacts of climate change on Wisconsin's natural, human, and built environments; and to assist in developing, recommending, and implementing climate adaptation strategies in Wisconsin. WICCI originated in 2007 as a partnership between the University of Wisconsin Nelson Institute and the Wisconsin Department of Natural Resources, and has since grown to include numerous other state, public, and private institutions. In 2011, WICCI released its First Assessment Report, which documents the efforts of over 200 individuals around the state in assessing vulnerability and estimating the risk that regional climate change poses to Wisconsin. The success of WICCI as an organization can be traced to its existence as a partnership between academic and state institutions, and as a boundary organization that catalyzes cross-disciplinary efforts between science and policy. WICCI's organizational structure and its past success at assessing climate impacts in Wisconsin will be briefly discussed. As WICCI moves into its second phase, it is increasing its emphasis on the second part of its mission: development, and implementation of adaptation strategies. Towards these goals WICCI has expanded its organizational structure to include a Communications and Outreach Committee that further ensures a necessary two-way communication of information between stakeholders / decision makers, and scientific efforts. WICCI is also increasing its focus on place-based efforts that include climate change information as one part of an integrated effort at sustainable development. The talk will include a discussion of current outreach and education efforts, as well as future directions for WICCI efforts.

  4. Sedimentary Record of Morasko Meteorite Impact in Lake Sediments from the Region of Poznań (Poland) — First Results

    NASA Astrophysics Data System (ADS)

    Pleskot, K.; Szczuciński, W.; Makohonienko, M.; Tjallingii, R.; Apolinarska, K.; Woszczyk, M.

    2015-09-01

    Our studies are focused on the influence of the Morasko meteorite impact on adjacent areas. Investigations are based on sedimentological archives of lakes located in the vicinity of the Morasko craters.

  5. Prolonged Effect of Severe Wildfires on Mercury and Other Volatiles in Forest Soils of the Lake Superior Region, USA

    NASA Astrophysics Data System (ADS)

    Cannon, W. F.; Woodruff, L. G.

    2003-12-01

    Soils in Isle Royale National Park, Michigan and Voyageurs National Park, Minnesota show spatial patterns of depletion of total Hg, organic C, Se, total S, P, and Pb within areas of severe, stand-replacing wildfires that burned in 1936, approximately 65 years prior to our current study. The fires burned during a regional drought, were of high severity, and likely consumed a high percentage of organic forest-floor material (O-horizon). A "fire factor" is defined by positive correlations among Hg, C, Se, S, P, and Pb. A factor score for this six-element grouping derived from factor analysis was assigned to each sample. The scores show a high spatial correlation with the footprint of the 1936 fires in both parks, particularly for A-horizon soils. Because many of these elements are volatile, and are highly correlated with soil organic matter, observed depletions likely represent instantaneous atmospheric release during combustion of O-horizon soils coupled with decades-long reduction of organic matter on the forest floor and near-surface soils. Nearly complete combustion of the modern O-horizon would release roughly 1 mg Hg/m2 from the forest floor. Decades-long disturbance resulting from destruction of mature forests and gradual regrowth following fire also play an important role in Hg cycling. Destruction of a mature forest results in decreased deposition of Hg from litterfall as well as throughfall, which contributes Hg by wash-off of dry deposited Hg from foliar surfaces. Hg in forest soils may follow a fire-dependent cycle in which sudden Hg loss during fire is followed by a period of continued Hg loss as evasion exceeds sequestration in the early stand-replacement stage, finally to resume gradual buildup in later stages of forest regrowth. In the Lake Superior region this cycle exceeds 65 years in duration and is of the same magnitude as the fire return interval for this region. Forests that are controlled by fire-induced cycles of stand replacement may also be

  6. Ecosystem response to Lateglacial and early Holocene climate oscillations in the Great Lakes region of North America

    NASA Astrophysics Data System (ADS)

    Yu, Zicheng

    2000-12-01

    replacement of Picea woodland by Pinus-dominated forest. The Picea recurrence at 9650 14C BP demonstrates sensitive response of ecotonal vegetation to the PB climate oscillation, which is also indicated by 0.4‰ negative excursion of δ18O. These new results suggest the importance of multiproxy records for reliable paleoclimate reconstruction. Reevaluation and revised chronologies of previously published sites (Gage Street, and Nichols Brook) in the eastern Great Lakes region show their major δ18O shifts correlative to the YD and PB oscillations as documented from Twiss Marl Pond and nearby Crawford Lake. The sequence and magnitude of climatic oscillations from these sites match in detail with records from the Atlantic Seaboard, suggesting that these oscillations are an expression of broad-scale, probably global, climate change rather than local meltwater-induced climate cooling.

  7. GRACE water storage estimates for the Middle East and other regions with significant reservoir and lake storage

    NASA Astrophysics Data System (ADS)

    Longuevergne, L.; Wilson, C. R.; Scanlon, B. R.; Crétaux, J. F.

    2013-12-01

    While GRACE (Gravity Recovery and Climate Experiment) satellites are increasingly being used to monitor total water storage (TWS) changes globally, the impact of spatial distribution of water storage within a basin is generally ignored but may be substantial. In many basins, water is often stored in reservoirs or lakes, flooded areas, small aquifer systems, and other localized regions with areas typically below GRACE resolution (~200 000 km2). The objective of this study was to assess the impact of nonuniform water storage distribution on GRACE estimates of TWS changes as basin-wide averages, focusing on surface water reservoirs and using a priori information on reservoir storage from radar altimetry. Analysis included numerical experiments testing effects of location and areal extent of the localized mass (reservoirs) within a basin on basin-wide average water storage changes, and application to the lower Nile (Lake Nasser) and Tigris-Euphrates basins as examples. Numerical experiments show that by assuming uniform mass distribution, GRACE estimates may under- or overestimate basin-wide average water storage by up to a factor of ~2, depending on reservoir location and areal extent. Although reservoirs generally cover less than 1% of the basin area, and their spatial extent may be unresolved by GRACE, reservoir storage may dominate water storage changes in some basins. For example, reservoir storage accounts for ~95% of seasonal water storage changes in the lower Nile and 10% in the Tigris-Euphrates. Because reservoirs are used to mitigate droughts and buffer against climate extremes, their influence on interannual timescales can be large. For example, TWS decline during the 2007-2009 drought in the Tigris-Euphrates basin measured by GRACE was ~93 km3. Actual reservoir storage from satellite altimetry was limited to 27 km3, but their apparent impact on GRACE reached 45 km3, i.e., 50% of GRACE trend. Therefore, the actual impact of reservoirs would have been greatly

  8. Vanishing glaciers, degrading permafrost, new lakes and increasing probability of extreme floods from impact waves - a need for long-term risk reduction concerning high-mountain regions

    NASA Astrophysics Data System (ADS)

    Haeberli, Wilfried; Schaub, Yvonne; Huggel, Christian; Boeckli, Lorenz

    2013-04-01

    As a consequence of continued global warming, rapid and fundamental changes are taking place in high-mountain regions. Within decades only, many still existing glacier landscapes will probably transform into new and strongly different landscapes of bare bedrock, loose debris, numerous lakes and sparse vegetation. These new landscapes are then likely to persist for centuries if not millennia to come. During variable but mostly extended parts of this future time period, they will be characterised by pronounced disequilibria within their geo- and ecosystems. Such disequilibria include a long-term stability reduction of steep/icy mountain slopes as a slow and delayed reaction to stress redistribution following de-buttressing by vanishing glaciers and to changes in strength and hydraulic permeability caused by permafrost warming and degradation. With the formation of many new lakes in close neighbourhood to, or even directly at the foot of, so-affected slopes, the probability of far-reaching flood waves from large rock falls into lakes is likely to increase for extended time periods. Quantitative information for anticipating possible developments exists in the European Alps. The present (2011) glacier cover is some 1800 km2, the still existing total ice volume 80 ± 20 km3 and the average loss rate about -2 km3 ice per year. The permafrost area has recently been estimated at some 3000 km2 with a total subsurface ice volume of 25 ± 2 km3; loss rates are hardly known but are certainly much smaller than for glaciers - probably by at least a factor of 10. Based on a detailed study for the Swiss Alps, total future lake volume may be assumed to be a few percent of the presently remaining glacier volume, i.e., a few km3 for the entire Alps. Forward projection of such numbers into the future indicates that glacier volumes tend to much more rapidly vanish than volumes of subsurface ice in permafrost, and lake volumes are likely to steadily increase. Already during the second

  9. Holocene changes in fire frequency in the Daihai Lake region (north-central China): indications and implications for an important role of human activity

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Xiao, Jule; Cui, Linlin; Ding, Zhongli

    2013-01-01

    Black carbon (BC) content in a sediment core from Daihai Lake, Inner Mongolia, was analyzed to reconstruct a high-resolution history of fires occurring in northern China during the Holocene and to examine the impacts of natural changes and human activities on the fire regime. The black carbon mass sedimentation rate (BCMSR) was disintegrated into two components: the background BCMSR and the BCMSR peak, with the BCMSR peak representing the frequency of fire episodes. Both the background BCMSR and the magnitude of the BCMSR peak display a close relation with the percentage of tree pollen from the same sediment core, suggesting that regional vegetation type would be a factor controlling the intensity of fires. The inferred fire-episode frequency for the Holocene exhibits two phases of obvious increases, i.e., the first increase from <5 to ˜10 episodes/1000 yrs occurring at 8200 cal. yrs BP when the vegetation of the lake basin shifted from grasses to forests and the climate changed from warm/dry to warm/humid condition, and the further increase to a maximum frequency of 13 episodes/1000 yrs occurring at 2800 cal. yrs BP when herbs and shrubs replaced the forests in the lake basin and the climate became cool/dry. Both increases in the fire frequency contradict the previous interpretation that fires occurred frequently in the monsoon region of northern China when steppe developed under the cold/dry climate. We thus suggest that human activities would be responsible for the increased frequencies of fires in the Daihai Lake region in terms that the appearance of early agriculture and the expansion of human land use were considered to take place in northern China at ca 8000 and 3000 cal. yrs BP, respectively.

  10. Lake Mead, NV

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Lake Mead, Nevada, (36.0N, 114.5E) where the water from the Colorado River empties after it's 273 mile journey through the Grand Canyon of Arizona is the subject of this photo. Other features of interest are Hoover Dam on the south shore of Lake Mead where cheap hydroelectric power is secondary to the water resources made available in this northern desert region and the resort city of Las Vegas, just to the west of Lake Mead.

  11. Forecast of spatially distributed runoff dynamics in the Finger Lakes region using an interactive web tool and Python

    NASA Astrophysics Data System (ADS)

    Dahlke, H. E.; Easton, Z. M.; Fuka, D. R.; Rao, N. S.; Steenhuis, T. S.

    2008-12-01

    To optimize NPS pollution reduction efficiency of Best Management Practices (BMPs) in NY State, various models have been developed that can effectively delineate runoff and contaminant source areas in the landscape. In the Finger Lakes region with shallow, permeable soils, underlain by a restricting layer, saturation excess runoff is the dominant mechanism of nutrient transport. In watersheds characterized by these conditions, runoff originates from areas in the landscape that expand and contract seasonally and are therefore often termed as variable source areas (VSAs). Hence, consideration should be given to the spatial distribution of VSA in the watershed during the planning process of BMPs. However, in practice the applied hydrological models often require extensive expertise and effort to be used on a routine basis for BMP planning. In order to simplify the BMP planning process, we developed an interactive web-based tool for Salmon Creek watershed, NY that locates VSA and calculates their probability of saturation. The interactive web tool incorporates hydrologic, geographic and land management information in an ESRI ArcIMS framework and presents the resulting VSA maps online. For the web tool we developed a Python-based application that calculates the surface runoff potential of the 230 km2 Salmon Creek watershed on the basis of a water balance model and free precipitation and temperature data from the National Climatic Data Center. Areas of high surface runoff potential are distributed via a soil topographic index to capture VSA dynamics. Further, the application is used to calculate a one to two day prediction of the spatial extent of VSA using free web- provided weather forecasts. The web tool is designed to interactively assist planners and especially farmers in the BMP planning process on a simplified expertise level. It can be used on a daily basis to locate fields with low runoff risk that could, potentially receive more liberal nutrient applications

  12. Schistosomiasis in a migrating population in the lake region of China and its potential impact on control operation.

    PubMed

    Cao, Chun-li; Bao, Zi-ping; Li, Shi-zhu; Wei, Wang-yuan; Yi, Ping; Yu, Qing; Zhu, Hong-qing; Xu, Jing; Guo, Jia-gang; Feng, Zheng

    2015-05-01

    Coverage of migrating people in schistosomiasis control program is a growing concern in China. Schistosomiasis caused by Schistosoma japonicum is still one of the major infectious diseases of public health importance in China though tremendous efforts have been made to control the transmission over the past decades. Along with the rapid social-economic development, migrant population has been remarkably increasing across the country. The infected migrants may introduce a new souse of infection to endemic areas or the areas where the transmission had been controlled or interrupted but the intermediate host Oncomelania snail is still present. Preliminary studies for surveillance on schistosomiasis prevalence in migrants were reported, but there is little basic information provided. We carried out an investigation on the prevalence in immigrants, emigrants and permanent residents in three villages of Hunan province located in the main endemic area of lake region, and analyzed the potential impact of migration on control practice. In the study villages, the migrant population accounts for 53.6% of the total. Schistosoma infection was detected by modified Kato-Katz method and miracidium hatching test. Questionnaire survey was conducted comprising knowledge of disease and its transmission, water contact, personal protective measures, and whether examined and treated after water contact. The survey indicated that the migrants and permanent residents had similar life style, and the majority of them experienced water contact in agricultural work or routine life activities. However, the infection rate in immigrants was significantly higher than that in permanent residents. It was also found that the migrants had significantly less knowledge about the disease than the permanent residents, and took no personal protective measures. This is due to that the control program could not cover the migrants when they were absent at the time the program being implemented. The present

  13. Seasonal Phenology and Life-History of Dendroctonus simplex (Coleoptera: Curculionidae) in the Great Lakes Region of North America.

    PubMed

    McKee, Fraser R; Aukema, Brian H

    2016-08-01

    The eastern larch beetle, Dendroctonus simplex LeConte (Coleoptera: Curculionidae), is distributed throughout the North American boreal forest sympatric with its primary host, the eastern larch or tamarack, Larix laricina (Du Roi) K. Koch. Outbreaks of eastern larch beetles are typically small and associated with stressed tamaracks. Since 2000, however, an outbreak has killed >90,000 ha of tamarack in Minnesota and surrounding Great Lakes region. Identifying the causes of this epidemic is challenging due to knowledge gaps regarding the insect's biology. We present field data from 2011 to 2014 on degree days associated with spring emergence, dispersal, host colonization, and re-emergence from colonized hosts by mature adult beetles, as well as degree days associated with larval development, and prewinter emergence by adult progeny at study sites in northern Minnesota. After initial host colonization in early spring we found that a second brood was established in early summer by re-emerging parents. In 2012, a third brood was established. Across study years, first broods developed to adults by late summer, with many beetles relocating to the base of the host tree to overwinter. Second broods often reached adulthood and initiated prewinter emergence. The third brood of 2012 overwintered as adults, pupae, and late-instars, resuming development the following spring. Each spring, emergence of adult beetles from all broods established the previous year was highly synchronous. Knowledge of the biology of eastern larch beetles along the southern margin of their range aids in understanding how population dynamics may change with a changing climate. PMID:27333874

  14. Geochemical evolution of Jurassic diorites from the Bristol Lake region, California, USA, and the role of assimilation

    USGS Publications Warehouse

    Young, E.D.; Wooden, J.L.; Shieh, Y.-N.; Farber, D.

    1992-01-01

    Late Jurassic dioritic plutons from the Bristol Lake region of the eastern Mojave Desert share several geochemical attributes with high-alumina basalts, continental hawaiite basalts, and high-K are andesites including: high K2O concentrations; high Al2O3 (16-19 weight %); elevated Zr/TiO2; LREE (light-rare-earth-element) enrichment (La/YbCN=6.3-13.3); and high Nb. Pearce element ratio analysis supported by petrographic relations demonstrates that P, Hf, and Zr were conserved during differentiation. Abundances of conserved elements suggest that dioritic plutons from neighboring ranges were derived from similar parental melts. In the most voluminous suite, correlated variations in elemental concentrations and (87Sr/86Sr)i indicate differentiation by fractional crystallization of hornblende and plagioclase combined with assimilation of a component characterized by abundant radiogenic Sr. Levenberg-Marquardt and Monte Carlo techniques were used to obtain optimal solutions to non-linear inverse models for fractional crystallization-assimilation processes. Results show that the assimilated material was chemically analogous to lower crustal mafic granulites and that the mass ratio of contaminant to parental magma was on the order of 0.1. Lack of enrichment in 18O with differentiation is consistent with the model results. Elemental concentrations and O, Sr, and Nd isotopic data point to a hydrous REE-enriched subcontinental lithospheric source similar to that which produced some Cenozoic continental hawaiites from the southern Cordillera. Isotopic compositions of associated granitoids suggest that partial melting of this subcontinental lithosphere may have been an important process in the development of the Late Jurassic plutonic arc of the eastern Mojave Desert. ?? 1992 Springer-Verlag.

  15. Seasonal changes in the concentrations of nitrogen and phosphorus in farmland drainage and groundwater of the Taihu Lake region of China.

    PubMed

    Chen, Xiaomin; Wo, Fei; Chen, Can; Fang, Kun

    2010-10-01

    To reduce the harmful effects of irrigated agriculture on the environment, the evaluation of alternative irrigation water management practices is essential. The contents of total-phosphorus, nitrate nitrogen, and ammonium nitrogen in rural aquatic bodies typical of the Taihu Lake region (Yixing, Wangzhuang, and Xinzhuang) were determined during 2 years. The results showed that the concentrations of nitrogen and phosphorus during the rainy season were higher than in other months. The concentration of ammonium nitrogen in farmland drainage was higher than that of nitrate nitrogen. Ammonium nitrogen and nitrate nitrogen were the main pollution sources in rural groundwater. However, the pollution by ammonium nitrogen was worse than nitrate nitrogen. The annual average values of ammonium nitrogen in Yixing and Wangzhuang were 1.596 and 2.103 mg L(-1); with maximum values of 5.782 and 5.441 mg L(-1), respectively, exceeding the lower limit for type V water quality by a factor of 10. Concentrations of nitrate nitrogen in groundwater in Xinzhuang from May to September exceeded the limit value (10 mg L(-1)) for drinking water prescribed by the World Health Organization. Therefore, this groundwater was not suitable to drink. In Taihu Lake, the average concentration of phosphorus over 2 years was 0.492 mg L(-1) and pollution by phosphorus in Taihu Lake was worse than other farmland drainage because of the trend of total-phosphorus accumulation. In addition, the average concentrations of nitrate nitrogen and ammonium nitrogen in Taihu Lake were 2.152 and 2.885 mg L(-1), respectively over 2 years, indicating that the water in the Taihu Lake is constantly in danger of eutrophication. Because of the transformation of ammonium nitrogen to nitrate nitrogen, there was a connection between the concentrations of ammonium nitrogen in farmland drainage and nitrate nitrogen in groundwater. There was also a significant positive linear correlation between the concentrations of ammonium

  16. Great Lakes Literacy Principles

    NASA Astrophysics Data System (ADS)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

    Lakes Superior, Huron, Michiga