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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

    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

  12. 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

  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. 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.

  11. 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.

  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. 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.

  3. 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.

  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

    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.

  15. 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.

  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

    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.

  7. 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

  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. 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.

  9. 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.

  10. 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

  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. 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...

  3. 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...

  4. 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...

  5. 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…

  6. 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)

  7. 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 ...

  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)

    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.

  6. 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.

  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. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  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. 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.

  18. 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.

  19. 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

  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. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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

  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. 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.

  15. 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

  16. 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.

  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. 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.

  2. 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

  3. 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

  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. 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...

  9. 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...

  10. 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…