Sample records for lake champlain sea

  1. Lake Champlain hydrodynamic monitoring program--An overview

    Microsoft Academic Search

    T. O. Manley; P. L. Manley; J. Saylor; K. L. Hunkins

    1993-01-01

    The Vermont Waters Research Center (VWRC) sponsored Lake Champlain Hydrodynamic Monitoring Program began in June 1991 through a cooperative program between Middlebury College, Lamont-Doherty Geological Observatory of Columbia University, and the Great Lakes Environmental Research Laboratory. This pilot program was designed to lead into a multi-year study of the internal mechanics of lake circulation (such as the variability of internal

  2. Mass balance assessment for mercury in Lake Champlain

    USGS Publications Warehouse

    Gao, N.; Armatas, N.G.; Shanley, J.B.; Kamman, N.C.; Miller, E.K.; Keeler, G.J.; Scherbatskoy, T.; Holsen, T.M.; Young, T.; McIlroy, L.; Drake, S.; Olsen, Bill; Cady, C.

    2006-01-01

    A mass balance model for mercury in Lake Champlain was developed in an effort to understand the sources, inventories, concentrations, and effects of mercury (Hg) contamination in the lake ecosystem. To construct the mass balance model, air, water, and sediment were sampled as a part of this project and other research/monitoring projects in the Lake Champlain Basin. This project produced a STELLA-based computer model and quantitative apportionments of the principal input and output pathways of Hg for each of 13 segments in the lake. The model Hg concentrations in the lake were consistent with measured concentrations. Specifically, the modeling identified surface water inflows as the largest direct contributor of Hg into the lake. Direct wet deposition to the lake was the second largest source of Hg followed by direct dry deposition. Volatilization and sedimentation losses were identified as the two major removal mechanisms. This study significantly improves previous estimates of the relative importance of Hg input pathways and of wet and dry deposition fluxes of Hg into Lake Champlain. It also provides new estimates of volatilization fluxes across different lake segments and sedimentation loss in the lake. ?? 2006 American Chemical Society.

  3. Mercury in the Pelagic Food Web of Lake Champlain

    PubMed Central

    Chen, Celia; Kamman, Neil; Shanley, James; Chalmers, Ann; Jackson, Brian; Taylor, Vivien; Smeltzer, Eric; Stangel, Pete; Shambaugh, Angela

    2013-01-01

    Lake Champlain continues to experience mercury contamination resulting in public advisories to limit human consumption of top trophic level fish such as walleye. Prior research suggested that mercury levels in biota could be modified by differences in ecosystem productivity as well as mercury loadings. We investigated relationships between mercury in different trophic levels in Lake Champlain. We measured inorganic and methyl mercury in water, seston, and two size fractions of zooplankton from 13 sites representing a range of nutrient loading conditions and productivity. Biomass varied significantly across lake segments in all measured ecosystem compartments in response to significant differences in nutrient levels. Local environmental factors such as alkalinity influenced the partitioning of mercury between water and seston. Mercury incorporation into biota was influenced by the biomass and mercury content of different ecosystem strata. Pelagic fish tissue mercury was a function of fish length and the size of the mercury pool associated with large zooplankton. We used these observations to parameterize a model of mercury transfers in the Lake Champlain food web that accounts for ecosystem productivity effects. Simulations using the mercury trophic transfer model suggest that reductions of 25 to 75% in summertime dissolved eplimnetic total mercury will likely allow fish tissue mercury concentrations to drop to the target level of 0.3 µg g?1 in a 40-cm fish in all lake segments. Changes in nutrient loading and ecosystem productivity in eutrophic segments may delay any response to reduced dissolved mercury and may result in increases in fish tissue mercury. PMID:22193540

  4. Wet deposition of mercury and ambient mercury concentrations at a site in the Lake Champlain basin

    Microsoft Academic Search

    J. Burke; M. Hoyer; G. Keeler; T. Scherbatskoy

    1995-01-01

    The “Great Waters” program, established in the 1990 Clean Air Act Amendments, mandated that atmospheric deposition of hazardous air pollutants to Lake Champlain (including Hg) be assessed. An assessment of the magnitude and seasonal variation of atmospheric Hg deposition in the Lake Champlain basin was initiated in December 1992 with one year of event precipitation collection, as well as collection

  5. Pollution detection in Lake Champlain using ERTS-1 imagery

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (principal investigator); Henson, E. B.

    1972-01-01

    The author has identified the following significant results. A major waste water discharge plume generated by a large paper mill along the New York shore of Lake Champlain was visually detected on ERTS-1 imagery. The plume is best displayed in 9.5 inch positive transparencies of MSS bands 4 and 5. Observation of the magnitude and extent of this plume is feasible, under magnification of 4 times. The chemical parameters of this plume have been documented by limnological studies. An enhancement technique useful for documenting the presence of waste water discharge plumes in Lake Champlain utilizes Polaroid MP-3 copy camera equipment and Spectral Data Corporation's multispectral viewer. The 9.5 inch, ERTS-1, positive transparency is enlarged using the Polaroid MP-3 copy camera to produce an enlarged lantern slide size positive transparency. These are projected through the multispectral viewer for enhancement and the scene is viewed directly on the screen or copied by an additional photographic step. The technique is simple and produces rapid results.

  6. Spatial and temporal variation in mercury bioaccumulation by zooplankton in Lake Champlain (North America)

    PubMed Central

    Kamman, Neil; Williams, Jason; Bugge, Deenie; Taylor, Vivien; Jackson, Brian; Miller, Eric

    2012-01-01

    Trophic transfer of Hg across lakes within a region has been related to multiple environmental factors, but the nature of these relationships across distinct basins within individual large lakes is unknown. We investigated Hg bioaccumulation in zooplankton in basins of differing trophic status in Lake Champlain (Vermont, USA) to determine the strongest predictors of Hg bioaccumulation. Zooplankton were sampled in Malletts Bay (oligotrophic) and Missisquoi Bay (eutrophic) in 2005–2008. Zooplankton in the eutrophic basin had lower concentrations of total Hg and MeHg than those in the oligotrophic basin in all years but 2007, when no bloom occurred in Missisquoi. In addition, Hg concentrations in seston and small zooplankton, sampled during 2009 at 12 sites spanning the lake, decreased with increasing phytoplankton and zooplankton biomass. Thus, Hg bioaccumulation in zooplankton across basins in Lake Champlain is related to trophic status, as observed previously in multiple lake studies. PMID:21995871

  7. Physical processes driving high-speed currents in Lake Champlain bottom water

    Microsoft Academic Search

    J. Saylor; J. Miller; T. O. Manley; P. L. Manley

    1993-01-01

    The authors have examined current velocity profiles obtained at two sites in Lake Champlain to delineate physical processes causing high-speed currents near the lake bottom. Acoustic Doppler Current Profilers (ADCP's) were deployed during the interval June--October, 1992 at mid-lake sites near Thompson's Point and Valcour Island. The instruments measured horizontal current velocity at 1 m intervals through the water column.

  8. Astronauts Cooper and Conrad arrive aboard U.S.S. Lake Champlain

    NASA Technical Reports Server (NTRS)

    1965-01-01

    A red-carpet welcome was staged for Astronauts L. Gordon Cooper Jr. and Charles Conrad Jr. as they arrive aboard the aircraft carrier U.S.S. Lake Champlain. They had been recovered from the Atlantic after the splashdown of their Gemini 5 spacecraft.

  9. Environmental study of ERTS-1 imagery Lake Champlain Basin and Vermont

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (principal investigator)

    1972-01-01

    The author has idenfified the following significant results. A first approximation land-type map using three categories of classification was generated for the Burlington area. The identification and mapping of a major turbidity front separating turbid waters of the southern arm of Lake Champlain from the clearer main water mass was reported on RBV 1 and 2 imagery and on subsequent MSS bands 4 and 5. Significant industrial pollution of Lake Champlain has degraded environmental quality in certain sections of the lake. Wetlands were detected and recognized using a combination of RBV bands 2 and 3. Using first-look RBV band 2 imagery, major ice marginal features were identified by using tonal patterns associated with vegetative cover. Major rivers were detected and recognized through the use of RBV band 3 imagery and MSS bands 6 and 7.

  10. Application of ERTS imagery to environmental studies of Lake Champlain

    NASA Technical Reports Server (NTRS)

    Lind, A. O.

    1974-01-01

    ERTS Imagery has provided data relating to a number of environmental and limnological concerns such as water quality, lake flooding and lake ice formation. Pollution plume data provided by ERTS was recently used in the Supreme Court case involving the States of Vermont and New York and a paper company. Flooding of lowland tracts has been a major concern due to a repetitive pattern of high lake levels over the past three years, and ERTS imagery is being used to construct the first series of flood maps of the affected areas. Lake ice development and turbidity patterns have also been studied from ERTS, since these have significance for shore erosion studies.

  11. Comparison of precision and bias of scale, fin ray, and otolith age estimates for lake whitefish ( Coregonus clupeaformis) in Lake Champlain

    Microsoft Academic Search

    Seth J. Herbst; J. Ellen Marsden

    2011-01-01

    We compared the precision, bias, and reader uncertainty of scales, dorsal fin rays, and otolith age estimates from 151 lake whitefish (Coregonus clupeaformis) from Lake Champlain, 2009. Mean and systematic differences in age estimates were compared among structures using consensus ages from two readers; precision of age structures was quantified through the use of age–bias plots, coefficient of variation, and

  12. New estimates of lethality of sea lamprey (Petromyzon marinus) attacks on lake trout (Salvelinus namaycush): Implications for fisheries management

    USGS Publications Warehouse

    Madenjian, C.P.; Chipman, B.D.; Marsden, J.E.

    2008-01-01

    Sea lamprey (Petromyzon marinus) control in North America costs millions of dollars each year, and control measures are guided by assessment of lamprey-induced damage to fisheries. The favored prey of sea lamprey in freshwater ecosystems has been lake trout (Salvelinus namaycush). A key parameter in assessing sea lamprey damage, as well as managing lake trout fisheries, is the probability of an adult lake trout surviving a lamprey attack. The conventional value for this parameter has been 0.55, based on laboratory experiments. In contrast, based on catch curve analysis, mark-recapture techniques, and observed wounding rates, we estimated that adult lake trout in Lake Champlain have a 0.74 probability of surviving a lamprey attack. Although sea lamprey growth in Lake Champlain was lower than that observed in Lake Huron, application of an individual-based model to both lakes indicated that the probability of surviving an attack in Lake Champlain was only 1.1 times higher than that in Lake Huron. Thus, we estimated that lake trout survive a lamprey attack in Lake Huron with a probability of 0.66. Therefore, our results suggested that lethality of a sea lamprey attack on lake trout has been overestimated in previous model applications used in fisheries management. ?? 2008 NRC.

  13. Lake Champlain 1° x 2° NTMS area New York, Vermont, and New Hampshire: data report (abbreviated). National Uranium Resource Evaluation program, hydrogeochemical and stream sediment reconnaissance

    Microsoft Academic Search

    Cook

    1981-01-01

    This abbreviated data report presents results of ground water and stream sediment reconnaissance in the National Topographic Map Series (NTMS) Lake Champlain 1° x 2° quadrangle. Surface sediment samples were collected at 1196 sites. Ground-water samples were collected at 619 sites. Neutron activation analysis (NAA) results are given for uranium and 16 other elements in sediments, for uranium and 8

  14. Great Lakes Region Sea Grant

    NSDL National Science Digital Library

    Site dedicated to the Great Lakes Sea Grant program. Information on GLSG priorities and initiatives. Topics of increased importance to the Great Lakes include fisheries and invasive species. Links to sites featuring publications and photos of Great Lakes storms and seiches and wildlife.

  15. Great Lakes Region Sea Grant

    NSDL National Science Digital Library

    This site is dedicated to the Great Lakes Sea Grant program. It provides information on the GLSG's priorities and initiatives. Topics of increased importance to the Great Lakes include fisheries and invasive species. Links to sites featuring publications and photos of Great Lakes storms and wildlife.

  16. Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

    USGS Publications Warehouse

    Medalie, Laura

    2014-01-01

    Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

  17. SEA LAMPREY CONTROL ON THE GREAT LAKES

    E-print Network

    SEA LAMPREY CONTROL ON THE GREAT LAKES 1953 AND 1954 1B logical lSSESI JUL 9 1956 WOODS HOLE, Mft of the Interior Fish and Wildlife Service, JohnL. Farley, Director SEA LAMPREY CONTROL ON THE GREAT LAKES 1953 Scientific Report--Fisheries No. 175 Washington, D.C May 1956 #12;ABSTRACT Development of electromechanical

  18. Ohio Sea Grant and Lake Erie Programs

    NSDL National Science Digital Library

    The Ohio Sea Grant and Lake Erie Programs are housed at The Ohio State University, and are responsible for maintaining a number of scientific laboratories and research endeavors that focus primarily on Lake Erie. A number of their most valuable online resources are made available on their homepage, including the Lake Erie Information Discussion Board (where visitors can get answers to Lake Erie-related questions) and the Sea Grant's work in creating artificial reefs in Lake Erie. Moving on from there, the homepage also contains a site index, where visitors can learn about the diverse research projects currently underway and view some of their online publications. One particular publication, "Twine Line", is quite useful, as it is geared towards the general public and includes coverage about Lake Erie and Great Lakes issues and research.

  19. Six flags over Champlain: Starting points for a comparative analysis

    Microsoft Academic Search

    L. Kinvin Wroth

    Six legal regimes have jurisdiction over the Lake Champlain Basin—the states of New York and Vermont, the province of Québec, the federal governments of the United States and Canada, and the regime of international law. Joint efforts to address the environmental needs of the Lake must work within – or around – the legal systems of these six jurisdictions and

  20. Toxic Cyanobacterial Bloom Triggers in Missisquoi Bay, Lake Champlain, as Determined by Next-Generation Sequencing and Quantitative PCR

    PubMed Central

    Fortin, Nathalie; Munoz-Ramos, Valentina; Bird, David; Lévesque, Benoît; Whyte, Lyle G.; Greer, Charles W.

    2015-01-01

    Missisquoi Bay (MB) is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes) and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP) ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages. PMID:25984732

  1. Toxic cyanobacterial bloom triggers in missisquoi bay, lake champlain, as determined by next-generation sequencing and quantitative PCR.

    PubMed

    Fortin, Nathalie; Munoz-Ramos, Valentina; Bird, David; Lévesque, Benoît; Whyte, Lyle G; Greer, Charles W

    2015-01-01

    Missisquoi Bay (MB) is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes) and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP) ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages. PMID:25984732

  2. Concentration, flux, and the analysis of trends of total and dissolved phosphorus, total nitrogen, and chloride in 18 tributaries to Lake Champlain, Vermont and New York, 1990–2011

    USGS Publications Warehouse

    Medalie, Laura

    2013-01-01

    Annual concentration, flux, and yield for total phosphorus, dissolved phosphorus, total nitrogen, and chloride for 18 tributaries to Lake Champlain were estimated for 1990 through 2011 using a weighted regression method based on time, tributary streamflows (discharges), and seasonal factors. The weighted regression method generated two series of daily estimates of flux and concentration during the period of record: one based on observed discharges and a second based on a flow-normalization procedure that removes random variation due to year-to-year climate-driven effects. The flownormalized estimate for a given date is similar to an average estimate of concentration or flux that would be made if all of the observed discharges for that date were equally likely to have occurred. The flux bias statistic showed that 68 of the 72 flux regression models were minimally biased. Temporal trends in the concentrations and fluxes were determined by calculating percent changes in flow-normalized annual fluxes for the full period of analysis (1990 through 2010) and for the decades 1990–2000 and 2000–2010. Basinwide, flow-normalized total phosphorus flux decreased by 42 metric tons per year (t/yr) between 1990 and 2010. This net result reflects a basinwide decrease in flux of 21 metric tons (t) between 1990 and 2000, followed by a decrease of 20 t between 2000 and 2010; both results were largely influenced by flux patterns in the large tributaries on the eastern side of the basin. A comparison of results for total phosphorus for the two separate decades of analysis found that more tributaries had decreasing concentrations and flux rates in the second decade than the first. An overall reduction in dissolved phosphorus flux of 0.7 t/yr was seen in the Lake Champlain Basin during the full period of analysis. That very small net change in flux reflects substantial reductions between 1990 and 2000 from eastern tributaries, especially in Otter Creek and the LaPlatte and Winooski Rivers that largely were offset by increases in the Missisquoi and Saranac Rivers in the second decade (between 2000 and 2010). The number of tributaries that had increases in dissolved phosphorus concentrations stayed constant at 13 or 14 during the period of analysis. Total nitrogen concentration and flux for most of the monitored tributaries in the Lake Champlain Basin have decreased since 1990. Between 1990 and 2010, flow-normalized total nitrogen flux decreased by 386 t/yr, which reflects an increase of 440 t/yr between 1990 and 2000 and a decrease of 826 t/yr between 2000 and 2010. All individual tributaries except the Winooski River had decreases in total nitrogen concentration and flux between 2000 and 2010. The decrease in total nitrogen flux over the period of record could be related to the decrease in nitrogen from atmospheric deposition observed in Vermont or to concurrent benefits realized from the implementation of agricultural best-management practices in the Lake Champlain Basin that were designed primarily to reduce phosphorus runoff. For chloride, large increases in flow-normalized concentrations and flux between 1990 and 2000 for 17 of the 18 tributaries diminished to small increases or decreases between 2000 and 2010. Between 1990 and 2010, flow-normalized flux increased by 32,225 t/yr, 78 percent of which (25,163 t) was realized during the first decade, from 1990 through 2000. The five tributaries that had decreasing concentration and flux of chloride between 2000 and 2010 were all on the eastern side of Lake Champlain, possibly related to reductions since 1999 in winter road salt application in Vermont. Positive correlations of phosphorus flux and changes in phosphorus concentration and flux in tributaries with phosphorus inputs to basins from point sources, suggest that point sources have an effect on stream phosphorus chemistry. Several measures of changes in agricultural statistics, such as agricultural land use, acres of land in farms, acres of cropland, and acres of corn for grain or seed, are positively correlated with changes in phosp

  3. Neutron activation analysis of sea-, lake-, and evaporated salt

    NASA Astrophysics Data System (ADS)

    Steinhauser, G.; Sterba, J. H.; Poljanc, K.; Bichler, M.; Buchtela, K.

    2006-01-01

    Salt is essential for human nutrition. Recently, it has become popular in Europe to rather use exotic sea salt or lake salt instead of purified evaporated salt, because of an alleged higher content of trace elements. In this study the content of trace elements and their bioavailability of 19 samples of different types of salt and 1 sample of brine purification sludge were investigated using instrumental neutron activation analysis. In general, sea-, lake-, and evaporated salt are quite pure. Trace elements determined in salt were Al, Br, Co, Cr, Cs, Fe, Rb, Sc, Sr, and Zn; some of them only in individual cases. It was found that, in general, the content of trace elements in sea- or lake salt was higher than in purified salt. Nevertheless, the use of sea- or lake salt does not contribute significantly to the human needs of essential trace elements, because their concentration in salt is too low or their compounds are not bioavailable.

  4. Lake trout (Salvelinus namaycush) and sea lamprey (Petromyzon marinus) populations in Lake Michigan, 1971-78

    USGS Publications Warehouse

    Wells, LaRue

    1980-01-01

    Lake trout (Salvelinus namaycush) was exterminated in Lake Michigan by the mid-1950s as a result of the combined effects of an intensive fishery and predation by the sea lamprey (Petromyzon marinus). The widespread application of lampricide in tributary streams had greatly reduced the abundance of lampreys by the early 1960s, and a program to restore self-sustaining populations of lake trout through stocking of yearlings and fingerlings was initiated in 1965. Although the hatchery-reared fish spawned widely in Lake Michigan each year after 1970, no progeny were observed except in an isolated area in Grand Traverse Bay. During 1971-78, sea lamprey abundance was generally greater in Wisconsin than in other parts of the lake. However, the rate of occurrence of sea lamprey wounds on lake trout dropped dramatically there in 1978 after the Peshtigo River, a tributary to Green Bay, was treated with lampricide. Application of Lake Michigan wounding rates to a regression model relating mortality to lamprey wounding developed from Lake Superior data, yielded lamprey-induced mortality estimates in 1977 of 5% in Michigan plus Indiana (combined) and 31% in Wisconsin; corresponding estimates for 1978 were 5 and 15%.

  5. Selenium Accumulation in Sea Ducks Wintering at Lake Ontario

    Microsoft Academic Search

    Michael L. Schummer; Shannon S. Badzinski; Scott A. Petrie; Yu-Wei Chen; Nelson Belzile

    2010-01-01

    Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer\\u000a some trace elements, such as selenium (Se) to higher

  6. Michigan Sea Grant Great Lakes Education

    NSDL National Science Digital Library

    Education programs provide fieldtrips, shipboard experiences, camps and projects focused on the Great Lakes. A science and multidisciplinary Great Lakes curriculum includes fisheries, aquatic food web, exotic species, water quality and weather. Teaching resources range from fact sheets to artifact trunks and CDs. Teacher training and workshops cover current topics and offer grant and fellowship opportunities.

  7. Predation by sea lamprey (Petromyzon marinus) on lake trout (Salvelinus namaycush) in southern Lake Ontario, 1982-1992

    USGS Publications Warehouse

    Schneider, C.P.; Owens, R.W.; Bergstedt, R.A.; O'Gorman, R.

    1996-01-01

    Dead lake trout (Salvelinus namaycush) killed by sea lamprey (Petromyzon marinus) were collected from the bottom of Lake Ontario using bottom trawls. The number of dead lake trout per hectare could be predicted from the number of type A-1 sea lamprey marks observed on live fish in September gillnet surveys (r2 = 0.60, P P > 0.05) from those of live fish with A-1 marks in 5 of 6 years where comparisons could be made. Compared with Lake Superior strain lake trout, Seneca Lake strain fish were only 0.41 times as likely to be attacked by sea lamprey and were less likely to die from an attack (both differences P < 0.05). Conservative estimates of the numbers of lake trout killed by sea lamprey in southern Lake Ontario from October to mid-November ranged from 17 000 in 1988 to 121 000 in 1984.

  8. The reconstruction of the Lake Champlain sidewheel steamer Champlain II 

    E-print Network

    Baldwin, Elizabeth Robinson

    1997-01-01

    the CTC's Shelbume Bay shipyard 135 10-6. The steamer Franklin. 136 10-7. The CTC steamer Burlington. . 137 10-8 The CTC steamer Canada. 138 10-9 The steamer Francis Saltus. . 139 10-10 The steamer A. Williams. 140 10-11 The steamer Adirondack. 142...

  9. Wind-driven currents in a shallow lake or sea

    NASA Technical Reports Server (NTRS)

    Goldstein, M. E.; Gedney, R. T.

    1971-01-01

    For shallow lakes and seas such as the great lakes (especially Lake Erie) where the depth is not much greater than the Ekman depth, the usual Ekman dynamics cannot be used to predict the wind driven currents. The necessary extension to include shallow bodies of water, given by Welander, leads to a partial differential equation for the surface displacement which in turn determines all other flow quantities. A technique for obtaining exact analytical solutions to Welander's equation for bodies of water with large class of bottom topographies which may or may not contain islands is given. It involves applying conformal mapping methods to an extension of Welander's equation into the complex plane. When the wind stress is constant (which is the usual assumption for lakes) the method leads to general solutions which hold for bodies of water of arbitrary shape (the shape appears in the solutions through a set of constants which are the coefficients in the Laurent expansion of a mapping of the particular lake geometry). The method is applied to an elliptically shaped lake and a circular lake containing an eccentrically located circular island.

  10. Evaluating the growth potential of sea lampreys (Petromyzon marinus) feeding on siscowet lake trout (Salvelinus namaycush) in Lake Superior

    USGS Publications Warehouse

    Moody, E.K.; Weidel, B.C.; Ahrenstorff, T.D.; Mattes, W.P.; Kitchell, J.F.

    2011-01-01

    Differences in the preferred thermal habitat of Lake Superior lake trout morphotypes create alternative growth scenarios for parasitic sea lamprey (Petromyzon marinus) attached to lake trout hosts. Siscowet lake trout (Salvelinus namaycush) inhabit deep, consistently cold water (4–6 °C) and are more abundant than lean lake trout (Salvelinus namaycush) which occupy temperatures between 8 and 12 °C during summer thermal stratification. Using bioenergetics models we contrasted the growth potential of sea lampreys attached to siscowet and lean lake trout to determine how host temperature influences the growth and ultimate size of adult sea lamprey. Sea lampreys simulated under the thermal regime of siscowets are capable of reaching sizes within the range of adult sea lamprey sizes observed in Lake Superior tributaries. High lamprey wounding rates on siscowets suggest siscowets are important lamprey hosts. In addition, siscowets have higher survival rates from lamprey attacks than those observed for lean lake trout which raises the prospect that siscowets serve as a buffer to predation on more commercially desirable hosts such as lean lake trout, and could serve to subsidize lamprey growth.

  11. Selenium Accumulation in Sea Ducks Wintering at Lake Ontario Michael L. Schummer Shannon S. Badzinski

    E-print Network

    Belzile, Nelson

    sea ducks, including buffleheads (Bucephala albeola; BUFF), common golden- eyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after

  12. Selenium accumulation in sea ducks wintering at Lake Ontario.

    PubMed

    Schummer, Michael L; Badzinski, Shannon S; Petrie, Scott A; Chen, Yu-Wei; Belzile, Nelson

    2010-04-01

    Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels. Se can be problematic for waterfowl and it often has been detected at elevated levels in organisms using the Great Lakes. There are, however, few data on hepatic Se concentrations in sea ducks, particularly during the winter at Lake Ontario. In this study, we evaluated interspecific differences and temporal trends in hepatic Se concentrations among BUFF (n = 77), COGO (n = 77), and LTDU (n = 79) wintering at Lake Ontario. All three species accumulated Se throughout winter, but COGO did so at a higher rate than did BUFF and LTDU. Overall, Se concentrations were higher in LTDU [mean = 22.7; 95% CI = 20.8-24.8 microg/g dry weight (dw)] than in BUFF ([mean = 12.3; 95% CI = 11.6-13.1 microg/g dw) and COGO ([mean = 12.0; 95% CI = 10.7-3.5 microg/g dw) throughout the winter. Se concentrations were deemed elevated (>33 microg/g dw) in 0%, 5%, and 19% of BUFF, COGO, and LTDU, respectively. Presently there are no data on Se toxicity end points for these species, so it is unclear how acquiring concentrations of these magnitudes affect their short- and long-term health or reproduction. PMID:19653029

  13. Subglacial Lake Whillans, West Antarctica; Solute Dynamics and Fluxes to the Ross Sea

    NASA Astrophysics Data System (ADS)

    Skidmore, M. L.; Michaud, A. B.; Achberger, A.; Barbante, C.; Christner, B. C.; Mikucki, J.; Mitchell, A. C.; Priscu, J. C.; Purcell, A. M.; van Gelder, W.; Vick-Majors, T.

    2014-12-01

    Subglacial Lake Whillans is located beneath the Whillans Ice Stream in West Antarctica. The lake is situated beneath 800 m of ice and ~ 70 km upstream of the grounding line where Whillans Ice Stream terminates into the Ross Sea. Subglacial Lake Whillans is a shallow lake and a component of a complex subglacial hydrological system that may resemble a large wetland along the Siple Coast of West Antarctica. Subglacial Lake Whillans drains and refills on a sub-decadal time scale discharging water towards the Ross Sea. Water and sediment samples were recovered from the lake, using clean access drilling technologies, in January, 2013. Isotopic analysis of the lake waters indicates basal meltwater from the ice sheet as the dominant water source. Geochemical analysis of the lake water reveals it is freshwater with mineral weathering as a significant solute source, with a minor contribution from sea water likely from relict marine sediments. Subglacial hydrothermal activity upstream may also contribute solutes. Nutrients N and P are present at micromolar concentrations. Sediment porewaters from shallow cores (~ 40 cm depth) of the subglacial lake sediments indicate increasing solute concentration with depth, with up to ~ five times greater solute concentrations than in the lake water. The waters and sediment contain metabolically active organisms which are likely involved in elemental cycling within the lake system. Here we will discuss solute sources to the lake, solute dynamics within the lake waters and sediment, and the fluxes of solute and nutrients to the Ross Sea and their implications for these marine ecosystems.

  14. Sea lamprey abundance and management in Lake Superior, 1957 to 1999

    USGS Publications Warehouse

    Heinrich, J.W.; Mullett, K.M.; Hansen, M.J.; Adams, J.V.; Klar, G.T.; Johnson, D.A.; Christie, G.C.; Young, R.J.

    2003-01-01

    The international sea lamprey (Petromyzon marinus) control program successfully laid the foundation for rehabilitation of lake trout (Salvelinus namaycush) in Lake Superior and was well coordinated among management agencies during 1957-1999. The lampricide TFM was the primary control tool, with recurring treatments in 52 larval-producing streams. Barriers and sterile-male-release, as alternative control technologies, were significant elements of the program. Barriers blocked spawning sea lampreys from substantial areas of habitat for sea lamprey larvae during 1966-1999, and the sterile-male-release technique was used to reduce larval production during 1991-1996. Sea lamprey control resulted in the suppression of sea lamprey populations in Lake Superior, as evidenced by the linear decline in spawner abundance during 1962-1999. However, sea lamprey abundance was not as low as the targets specified in the fish community objectives. Most of the parasitic sea lampreys in Lake Superior probably originated from survivors of lampricide treatments. Self-sustaining populations of lake trout were restored in most of the lake by 1996, although many were killed annually by sea lampreys. Economic injury levels for damage to fish populations by sea lampreys are being developed and will be used to distribute sea lamprey control resources among the Great Lakes.

  15. Sea lamprey abundance and management in Lake Superior 1957-1999

    USGS Publications Warehouse

    Heinrich, John W.; Mullett, Katherine M.; Hansen, Michael J.; Adams, Jean V.; Klar, Gerald T.; Johnson, David A.; Christie, Gavin C.; Young, Robert J.

    2003-01-01

    The international sea lamprey (Petromyzon marinus) control program successfully laid the foundation for rehabilitation of lake trout (Salvelinus namaycush) in Lake Superior and was well coordinated among management agencies during 1957-1999. The lampricide TFM was the primary control tool, with recurring treatments in 52 larval-producing streams. Barriers and sterile-male-release, as alternative control technologies, were significant elements of the program. Barriers blocked spawning sea lampreys from substantial areas of habitat for sea lamprey larvae during 1966-1999, and the sterile-male-release technique was used to reduce larval production during 1991-1996. Sea lamprey control resulted in the suppression of sea lamprey populations in Lake Superior, as evidenced by the linear decline in spawner abundance during 1962-1999. However, sea lamprey abundance was not as low as the targets specified in the fish community objectives. Most of the parasitic sea lampreys in Lake Superior probably originated from survivors of lampricide treatments. Self-sustaining populations of lake trout were restored in most of the lake by 1996, although many were killed annually by sea lampreys. Economic injury levels for damage to fish populations by sea lampreys are being developed and will be used to distribute sea lamprey control resources among the Great Lakes.

  16. Organochlorine Contaminants in Water, Sediment and Fish of Lake Burullus, Egyptian Mediterranean Sea

    Microsoft Academic Search

    Tarek O. Said; Khaled M. El Moselhy; Abdel Aziz M. Rashad; Mohamed A. Shreadah

    2008-01-01

    Lake Burullus is one of the Delta lakes, connected with the Mediterranean Sea through El Boughaz opening. Concentrations of\\u000a organochlorine contaminants were measured in water, sediments and biota of the lake because of concerns about their effects\\u000a on its productivity. The concentrations of chlorinated hydrocarbons decreased in the order of PCBs > DDTs > TC > HCHs for\\u000a all water samples collected from Lake Burullus during

  17. Calcium, magnesium and strontium cycling in stratified, hardwater lakes: Lake Kinneret (Sea of Galilee), Israel

    NASA Astrophysics Data System (ADS)

    Katz, Amitai; Nishri, Ami

    2013-03-01

    In stratified hardwater lakes, calcite crystallization in the epilimnion and partial dissolution in the hypolimnion play important roles in the cycling of Ca2+ in the water column. Mg2+ and Sr2+ coprecipitate with this mineral, to be released together with Ca2+ upon its dissolution. Here, we focus on Lake Kinneret (Sea of Galilee, Israel), a stratified, warm, hardwater lake, searching for an interpretable, high resolution picture of the processes that drive Ca2+, Mg2+ and Sr2+cycling in this and similar lakes elsewhere. In total, 1428 water samples were collected from the lake, and another 81 samples were collected from the Jordan River and two small streams discharging into it, covering a full monomictic cycle from December 2001 through March 2003. Particulate material was retrieved from sediment traps in the hypolimnion. The water samples were analyzed for Na+, K+, Mg2+, Ca2+, Sr2+, Cl-, SO42-, HCO3- and Br-, and the trapped particulates were examined under SEM and analyzed for their Ca, Mg, and Sr content. Individual calcite crystals within the particulate material underwent LA-ICP-MS analysis for Ca, Mg, and Sr. Downward transport of Ca2+ involves crystallization of calcite in the epilimnion, followed by its settling through the water column, followed by its partial dissolution in the hypolimnion. Magnesium and Sr2+ follow Ca2+ by coprecipitation in calcite and are released upon its dissolution in the hypolimnion. Upward cycling of the three solutes occurs through an admixture of the hypolimnetic water into the epilimnion during thermocline deepening, terminated by overturn of the lake. Removal rates of Mg2+ and Sr2+ from the lake, relative to that of Ca2+, and the water-calcite distribution coefficients, DMg and DSr, were calculated from the analyses using: (1) epilimnion water and 'bulk' particulates; (2) epilimnion water only; and (3) epilimnion water and calcite crystals in the particulates. The DSr values obtained were internally consistent (0.194 ± 5.9%, 0.22-0.28, and 0.204-0.232, respectively); however, the DMg value for the 'bulk' particulates (0.0477) was ˜6 times higher than that corresponding to calcite crystals included therein (0.00841). This difference is attributed to phytoplankton debris in the 'bulk' particulates and should be of concern to geochemists using Mg/Ca ratios in limestone to reconstruct ancient aquatic environments. The cycling of Ca2+, Mg2+ and Sr2+ in the stratified lake is monitored by Mg/Ca vs. Sr/Ca regression diagrams, where each line represents the water column composition on a specific date. The distance of the data points from the initial (mixed lake) coordinates reflects the fractionation of Ca2+, Mg2+ and Sr2+ after the onset of stratification. The regression lines rotate in an orderly anticlockwise direction in response to the high calcite flux from the epilimnion in spring and the higher rate of Mg2+ replenishment than that of Sr2+, compensating for their loss in calcite. The release of Mg2+ and Sr2+ from dissolving calcite in the hypolimnion, at an Mg/Sr ratio (7.5 eq/eq) much lower than that in the surrounding water (˜160 eq/eq), lends additional support to the anticlockwise rotation. Reversal of rotation occurs in summer, when calcite crystallization and the freshwater supply slow down, and brackish and saline water sources take control over the Mg/Sr ratio in the lake. Subsequent turnover and mixing of the lake in winter reset the Mg/Ca and Sr/Ca ratios to their original values before the next stratification.

  18. Development and validation of a regional coupled atmosphere lake model for the Caspian Sea Basin

    NASA Astrophysics Data System (ADS)

    Turuncoglu, Ufuk Utku; Elguindi, Nellie; Giorgi, Filippo; Fournier, Nicolas; Giuliani, Graziano

    2013-10-01

    We present a validation analysis of a regional climate model coupled to a distributed one dimensional (1D) lake model for the Caspian Sea Basin. Two model grid spacings are tested, 50 and 20 km, the simulation period is 1989-2008 and the lateral boundary conditions are from the ERA-Interim reanalysis of observations. The model is validated against atmospheric as well as lake variables. The model performance in reproducing precipitation and temperature mean seasonal climatology, seasonal cycles and interannual variability is generally good, with the model results being mostly within the observational uncertainty range. The model appears to overestimate cloudiness and underestimate surface radiation, although a large observational uncertainty is found in these variables. The 1D distributed lake model (run at each grid point of the lake area) reproduces the observed lake-average sea surface temperature (SST), although differences compared to observations are found in the spatial structure of the SST, most likely as a result of the absence of 3 dimensional lake water circulations. The evolution of lake ice cover and near surface wind over the lake area is also reproduced by the model reasonably well. Improvements resulting from the increase of resolution from 50 to 20 km are most significant in the lake model. Overall the performance of the coupled regional climate—1D lake model system appears to be of sufficient quality for application to climate change scenario simulations over the Caspian Sea Basin.

  19. Wind Fields over the Great Lakes Measured by the SeaWinds Scatterometer on the QuikSCAT Satellite

    E-print Network

    Wind Fields over the Great Lakes Measured by the SeaWinds Scatterometer on the QuikSCAT Satellite and Atmospheric Administration Great Lakes Environmental Research Laboratory 2205 Commonwealth Blvd. Ann Arbor for wind retrieval over the Great Lakes on a daily basis. We use data acquired by the Sea

  20. The late Quaternary limnological history of Lake Kinneret (Sea of Galilee), Israel

    E-print Network

    Marco, Shmuel "Shmulik"

    The late Quaternary limnological history of Lake Kinneret (Sea of Galilee), Israel N. Hazana , M) during the Neogene­Quartenary periods. We reconstructed the limnological history (level and composition

  1. Diatoms as food of larval sea lampreys in a small tributary of northern Lake Michigan

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

    The food and food preferences of sea lamprey ammocoetes have not been investigated. The food of the larval American brook lamprey, Lampetra lamottei, in the Great Lakes region consisted mainly of diatoms and desmids according to Creaser and Hann. Schroll discussed the biology of feeding of ammocoetes of Lampetra planeri and Eudontomyzon danfordi in Europe. This report presents data on the availability and use of diatoms by sea lamprey, Petromyzon marinus Linnaeus, ammocoetes in a small tributary of northern Lake Michigan.

  2. Impact of Environmental Conditions on the Phytoplankton Structure in Mediterranean Sea Lagoon, Lake Burullus, Egypt

    Microsoft Academic Search

    Mohamed A. Okbah; Nabila R. Hussein

    2006-01-01

    Lake Burullus is one of the northern Delta lakes, connected with the Mediterranean Sea through El-Boughaz opening. The main\\u000a objective of the present work is to study the physical and chemical properties of the lake and its relation with the phytoplankton\\u000a communities, chlorophyll-a as well as diversity and Eutrophication index. The studies revealed that, the pH values lie in alkaline

  3. Survival of Rainbow Trout and Lake Trout after Sea Lamprey Attack

    Microsoft Academic Search

    William D. Swink; Lee H. Hanson

    1989-01-01

    Survival was significantly higher (P = 0.054) for rainbow trout Oncorhynchus mykiss (formerly Salmo gairdneri) than for lake trout Salvelinus namaycush when the fish were subjected in the laboratory to a single attack by a sea lamprey Petromyzon marinus. Of 77 rainbow trout, 40% died (35% by direct attack and 5% by secondary infection) and 60% survived; of 77 lake

  4. Road salt turning Twin Cities lakes into dead seas By JOSEPHINE MARCOTTY, Star Tribune

    E-print Network

    Minnesota, University of

    Road salt turning Twin Cities lakes into dead seas By JOSEPHINE MARCOTTY, Star Tribune March 23 in lakes and streams around the Twin Cities -- road salt. The fish, bugs and other wildlife that live, a primary ingredient in salt, and what it will take to keep urban waters healthy. But the far more difficult

  5. Investigating the Great Lakes Environment, Unit One: The Sea Lamprey Story.

    ERIC Educational Resources Information Center

    Lin, Leslie; And Others

    Presented are 11 middle school activities dealing with the sea lamprey and its impact upon the Great Lakes. Included are background information, lesson outlines, references, masters for student worksheets, a wall map, game boards, and two filmstrip-tape units. Using these materials students can learn ecological concepts and some Great Lakes

  6. Evidence that sea lamprey control led to recovery of the burbot population in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Madenjian, C.P.; Witzel, L.D.

    2006-01-01

    Between 1987 and 2003, the abundance of burbot Lota lota in eastern Lake Erie increased significantly, especially in Ontario waters. We considered four hypotheses to explain this increase: (1) reduced competition with lake trout Salvelinus namaycush, the other major coldwater piscivore in Lake Erie; (2) increased abundance of the two main prey species, rainbow smelt Osmerus mordax and round goby Neogobius melanostomus; (3) reduced interference with burbot reproduction by alewives Alosa pseudoharengus; and (4) reduced predation by sea lampreys Petromyzon marinus on burbot. Species abundance data did not support the first three hypotheses. Our results suggested that the apparent recovery of the burbot population of Lake Erie was driven by effective sea lamprey control. Sea lamprey predation appeared to be the common factor affecting burbot abundance in Lakes Michigan, Huron, Erie, and Ontario. In addition, relatively high alewife density probably depressed burbot abundance in Lakes Ontario and Michigan. We propose that a healthy adult lake trout population may augment burbot recovery in some lakes by serving as a buffer against sea lamprey predation and will not negatively impact burbot through competition. ?? Copyright by the American Fisheries Society 2006.

  7. Small eddies observed in Lake Superior using SAR and sea surface temperature imagery

    E-print Network

    Matsumoto, Katsumi

    experiment from the 1890s (Harrington, 1895) and current meter data from the 1960s (Sloss and Saylor, 1976 currents contribute to counterclockwise flow (Bennington et al., 2010). Lake Su- perior exhibitsSmall eddies observed in Lake Superior using SAR and sea surface temperature imagery Paul Mc

  8. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Champlain Valley Interstate Air Quality Control Region. 81.48 Section...PURPOSES Designation of Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain...

  9. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Champlain Valley Interstate Air Quality Control Region. 81.48 Section...PURPOSES Designation of Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain...

  10. Transient groundwater-lake interactions in a continental rift: Sea of Galilee, Israel

    USGS Publications Warehouse

    Hurwitz, S.; Stanislavsky, E.; Lyakhovsky, V.; Gvirtzman, H.

    2000-01-01

    The Sea of Galilee, located in the northern part of the Dead Sea rift, is currently an intermediate fresh-water lake. It is postulated that during a short highstand phase of former Lake Lisan in the late Pleistocene, saline water percolated into the subsurface. Since its recession from the Kinarot basin and the instantaneous formation of the fresh-water lake (the Sea of Galilee), the previously intruded brine has been flushed backward toward the lake. Numerical simulations solving the coupled equations of fluid flow and of solute and heat transport are applied to examine the feasibility of this hypothesis. A sensitivity analysis shows that the major parameters controlling basin hydrodynamics are lake-water salinity, aquifer permeability, and aquifer anisotropy. Results show that a highstand period of 3000 yr in Lake Lisan was sufficient for saline water to percolate deep into the subsurface. Because of different aquifer permeabilities on both sides of the rift, brine percolated into a aquifers on the western margin, whereas percolation was negligible on the eastern side. In the simulation, after the occupation of the basin by the Sea of Galilee, the invading saline water was leached backward by a topography-driven flow. It is suggested that the percolating brine on the western side reacted with limestone at depth to form epigenetic dolomite at elevated temperatures. Therefore, groundwater discharging along the western shores of the Sea of Galilee has a higher calcium to magnesium ratio than groundwater on the eastern side.

  11. Effect of size on lake trout survival after a single sea lamprey attack

    USGS Publications Warehouse

    Swink, William D.

    1990-01-01

    When lake trout Salvelinus namaycush were subjected to a single attack by a sea lamprey Petromyzon marinus in laboratory tests in 1986, percentage mortality was significantly higher in small fish (64%; 469-557 mm; N = 67) than in medium (44%; 559-643 mm; N = 45) or large fish (43%; 660-799 mm; N = 47). Additional studies conducted in 1987 with 55 medium (559-650 mm) and 52 large (660-825 mm) lake trout confirmed that there was no difference in mortality between the two larger size-groups. Mortality declined in lake trout over 559 mm, but was still greater than 43%. This level of mortality and the sea lampreys' apparently active selection of larger fish indicated that, contrary to previously published opinions, large size in lake trout (up to ?800 mm in length) might not allow better survival from single sea lamprey attacks.

  12. Vermont Water Resources and Lake Studies Center Annual Technical Report

    E-print Network

    of satellite imagery to detect the presence and extent of blooms of blue-green algae in Lake Champlain of an Alpine Ski Resort on Hydrology and Water Quality in the Northeastern U.S.: Preliminary Findings from

  13. Lethality of sea lamprey attacks on lake trout in relation to location on the body surface

    USGS Publications Warehouse

    Bergstedt, Roger A.; Schneider, Clifford P.; O'Gorman, Robert

    2001-01-01

    We compared the locations of healed attack marks of the sea lamprey Petromyzon marinus on live lake trout Salvelinus namaycush with those of unhealed attack marks on dead lake trout to determine if the lethality of a sea lamprey attack was related to attack location. Lake trout were collected from Lake Ontario, live fish with gill nets in September 1985 and dead fish with trawls in October 19831986. Attack location was characterized by the percent distances from snout to tail and from the ventral to the dorsal midline. Kolmogorov-Smirnov two-sample tests did not detect significant differences in the distribution of attack location along either the anteroposterior axis or the dorsoventral axis. When attack locations were grouped into six anatomical regions historically used to record sea lamprey attacks, dead fish did not exhibit a significantly higher proportion of attacks in the more anterior regions. Even if the differences in attack location on live and dead fish were significant, they were too small to imply substantial spatial differences in attack lethality that should be accounted for when modeling the effects of sea lampreys feeding on lake trout. We suggest that the tendency for sea lamprey attacks to occur on the anterior half of the fish is related to the lower amplitude of lateral body movement there during swimming and thus the lower likelihood of being dislodged.

  14. Lake Baikal in southeastern Siberia,the "Sacred Sea,"incites strong emotions and action in Russia. In March 2006,

    E-print Network

    Dever, Jennifer A.

    Articles Lake Baikal in southeastern Siberia,the "Sacred Sea,"incites strong emotions and action pipeline scheduled to pass within 800 me- ters (m) of Lake Baikal's shoreline, and, within days, President,Russia,located within the airshed of Lake Baikal; one protester was killed and several were seriously injured by young

  15. Effect of water temperature on sea lamprey growth and lake trout survival

    SciTech Connect

    Swink, W.D. (Hammond Bay Biological Station, Millersburg, MI (United States))

    1993-11-01

    Percent mortality of lake trout Salvelinus namaycush subjected to single sea lamprey Petromyzon marinus attacks did not differ significantly between lower-temperature (mortality = 54%; temperature [le] 10[degrees]C; N = 33) and higher-temperature (mortality = 69%; temperature = 12.8-14.4[degrees]C; N = 45) laboratory studies conducted from 1 June to 28 November 1989. However, sea lampreys fed longer and killed fewer fish in colder water (mean attachment 467.0 h; 18 fish killed) than in warmer water (mean attachment 161.7 h; 31 fish killed), probably because food consumption was lower in colder water. These results indicate that the number of fish killed by sea lampreys could be much greater in warmer water and that temperature must be considered when fish losses from sea lamprey attacks are estimated. Previous studies (Swink and Hanson 1989; Swink 1990) of the effects of single sea lamprey Petromyzon marinus attacks on lake trout Salvelinus namaycush showed significantly less lake trout mortality at temperatures of 10[degrees]C and lower than at higher temperatures. The reduced host mortality, however, could not be attributed solely to lower temperature because warmwater and coldwater attacks occurred during different seasons. In those studies, the author was unable to hold water temperature at 10[degrees]C or less in late summer and early fall, when most fish are killed by sea lampreys in the Great Lakes (Christie and Kolenosky 1980; Bergstedt and Schneider 1988). Modifications to the fish holding facilities at the Hammond Bay Biological Station in 1988 allowed maintenance of a limited amount of water at 10[degrees]C or less throughout the year. Hence, the objective of this study was to compare sea lamprey-induced mortality of lake trout at 10[degrees]C or less with that at 12.8-14.4[degrees]C during the normal feeding season (June through November). 15 refs., 1 fig., 1 tab.

  16. Effects of nonlethal sea lamprey attack on the blood chemistry of lake trout

    USGS Publications Warehouse

    Edsall, Carol Cotant; Swink, William D.

    2001-01-01

    A laboratory study examined changes in the blood chemistry of field-caught and hatchery-reared lake trout Salvelinus namaycush subjected to a nonlethal attack by sea lampreys Petromyzon marinus. We measured glucose, total protein, amylase, alkaline phosphatase (ALKP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase, calcium, magnesium, triglycerides, sodium, and potassium with a Kodak Ektachem DT60 Analyzer, Ektachem DTSC Module, and the DTE Module. Mean levels of total protein, AST, ALKP, hematocrit, calcium, magnesium, and sodium decreased significantly (Pa?? 0.05), and mean levels of ALT and potassium increased significantly (Pa?? 0.05) after sea lamprey feeding. Lake trout condition (K) and hematocrit levels also decreased significantly (Pa?? 0.05) after the sea lamprey attack. Frequency distributions of eight lake trout blood chemistry variables and the hematocrit were significantly different before and after a sea lamprey attack. A second study that used hatchery lake trout broodstock measured changes in hematocrit before and after a sea lamprey attack.

  17. The possibility and timing for a sea waterway via the Lake Iznik (Turkey)

    NASA Astrophysics Data System (ADS)

    Alpar, B.

    2012-04-01

    The Sea of Marmara is connected to the Black Sea through the Bosporus strait. The idea of another waterway existed between these seas during the late Quaternary is much of great interest to scientific community. Taking into account the marine microfaunal composition collected from lake surface sediments some researchers claim that there was an alternative waterway connection via the lakes of Iznik and Sapanca, located at the eastward extensions of the Gulf of Gemlik and Izmit Bay, respectively. In addition a Holocene age is suggested for the latest flooding event. On the contrary, other researchers who have questioned the possibility for a waterway connection through these lakes and the lower course of Sakarya River during the Holocene or the late Pleistocene, claim that a marine connection could not be possible for at least the past 500,000 years. On the basis of the global sea-level change and regional tectonic uplift rates, for example, a connection between the Lake Iznik and the Sea of Marmara may not have been possible after 310,000 years BP. Both of the lakes, representing adjacent E-W-oriented narrow depressions, are controlled by the transpressional effects of the northern and central segments of the North Anatolian Fault (NAF) zone since the Late Miocene - Pliocene. On the basis of available seismic reflection data, the deep trough along the southern margin of Lake Iznik has been evolved under the control of a releasing bend system. Similar to the Hersek Pass separating the outer and central sub-basins of the Izmit Bay at present, this system formed the Karsak Pass between the Lake Iznik and the Gulf of Gemlik, and the brackish waters discharged into the Sea of Marmara. At present, the central segment of the NAF cuts this system and extends towards the Gulf of Gemlik, which is separated from the Lake Iznik by the uplifted Karsak sill (+83 m), similar to the pressure ridge on the Hersek Delta. Therefore the main trough of the Lake Iznik existed before the evolution of the NAF, implying that the lake is a superimposed basin. The secondary normal faults observed in the lake and its environs are responsible for the vertical tectonic movements. Depending on these regional changes and those occurred in the east of the Lake Iznik, e.g. a transpressional interruption at Pamukova, the water discharge ceased at the end of middle Pleistocene, even more precise reconstruction of the sea flooding history of the region need other supportive data. The distribution of some dominant benthic foraminifers across the biogeographic barriers can be explained by adaptation of some marine microfaunal composition to their new home. The transition from normal-marine waterway to a brackish lake fauna must be marked by decreases in species diversity about 310,000 years ago. At present the water quality of the Lake Iznik is changing towards mesotrophic stage from brackish stage. Their biogeographic imprints should be looked for in the composition of the entire assemblage, in general, rather than in the presence or absence of a few dominant species.

  18. Levels of heavy metals in seals of Lake Ladoga and the White Sea

    Microsoft Academic Search

    N. Medvedev; N. Panichev; H. Hyvärinen

    1997-01-01

    Between 1990 and 1993 samples of hair, liver, kidney and muscle were collected from 28 ringed seals from Lake Ladoga, Phoca hispida ladogensis, 20 ringed seals, Phoca hispida hispida, and three bearded seals, Erignathus barbatus, from the White Sea for heavy-metal residue analyses in tissues. The concentration of Hg, Cd, Pb, Cu, Ni and Zn were determined by atomic absorption

  19. Late-Quaternary morphostratigraphy of Lake St-Joseph (southeastern Canadian Shield): Evolution from a semi-enclosed glacimarine basin to a postglacial lake

    NASA Astrophysics Data System (ADS)

    Normandeau, Alexandre; Lajeunesse, Patrick; Philibert, Geneviève

    2013-09-01

    This paper reports and describes multibeam echosounder, subbottom profiler and sediment sampling data collected in Lake St-Joseph (southern Québec), a formerly glacimarine sedimentary basin that has been glacio-isostatically uplifted to form a small lake. Its study provides a unique opportunity for investigating changes in sedimentary environments from a glacial sea to a postglacial lake. Multibeam bathymetry allows the observation of two basins separated by a bathymetric ridge and of mass movement deposits in both basins. High resolution seismic stratigraphy reveals the presence of seven seismic units. These seven units relate to the advance and retreat of the Laurentide ice-sheet over the region. Following ice-retreat, transparent (U3) and high amplitude reflection (U4) units were deposited during the Champlain Sea invasion. The transparent unit likely represents a rapidly retreating glacier, which allowed the deposition of massive silt and clay, whereas the high amplitude reflectors, which are internally composed of transparent to chaotic lenses, are interpreted as the result of a deceleration of ice-retreat or a stabilization of the glacier and of glacio-isostatic rebound. Overlying the Champlain Sea sediments, a unit composed of smaller laminations (U5) suggests that it was deposited during the marine to lacustrine transition, in a paraglacial environment. This is supported by its presence in the northern basin, where the Rivière-aux-Pins mouth is located and its absence in the southern basin, where no river is observed. The bathymetric ridge between the two basins thus limited sediment transport. Following the complete retreat of the Champlain Sea, organic-rich sediments (U7) were deposited in the lake. In the northern basin, the presence of the Rivière-aux-Pins allowed their deposition in the form of rhythmites whereas the absence of rivers in the southern basin resulted in the deposition of an acoustically transparent unit. A mass movement (U6) identified during the deposition of Unit 7 occurred around 1250 AD and is interpreted as earthquake-triggered.

  20. Constraining the activity of waves on Titan's polar lakes and seas

    NASA Astrophysics Data System (ADS)

    Soderblom, Jason M.; Barnes, Jason W.; Brown, Robert H.; Soderblom, Laurence A.; Sotin, Christophe; Clark, Roger N.; Le Mouélic, Stéphane; Rodriguez, Sebastien; Baines, Kevin H.; Buratti, Bonnie J.; Nicholson, Philip D.

    2015-04-01

    Saturn's moon Titan has an active hydrological cycle in which the primary working fluid, methane, is thought to transport between poles on seasonal timescales, driving much of the observed meteorology. Surface winds play a critical role in determining the evaporation rates of methane from Titan's polar lakes and seas. Observational constraints on these winds, however, are limited. Aeolian landforms, in particular sand dunes, characterize Titan's mid latitudes, providing evidence that winds at these latitudes have, at least in the geologically recent past, exceeded the threshold for saltation (which recent work has shown might be higher than previously predicted). The shoreline morphology of Titan's lone large southern lake, Ontario Lacus, has been interpreted as evidence for wave erosion. Evidence for wave activity on Titan's lakes and seas, however, has been notably absent in Cassini observations. Explanations that have been forwarded to explain the lack of waves include the possibility that the liquids that comprise Titan's lakes and seas are highly viscous or that seasonal winds have not exceeded the threshold for capillary wave formation (Hayes et al., 2012, Icarus 225). Only recently have Cassini Visual and Infrared Mapping Spectrometer (VIMS) observations provided the first evidence of wave activity on Titan, in the north as Titan progresses towards northern summer (Barnes et al., 2014, Planetary Science 3). Herein, we use Cassini VIMS observations of the specular reflection of sunlight from Titan's lakes to infer the presence or absence of waves on Titan. We investigate observations acquired between 2012 and 2014. We find evidence for the presence of waves on Kraken Mare during a number of flybys, while specular reflections from the smaller Jingpo Lacus are more consistent with a smooth lake surface.

  1. Annual and Longer Sedimentary Rhythms of the Organic Rock Record of Titan's Circumpolar Seas and Lakes

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Tan, S. P.; Marion, G. M.; Jennings, D. E.; Mastrogiuseppe, M.; Adidharma, H.

    2014-12-01

    Seasonality and phase equilibrium in Titan's lakes and seas will result in predictable sedimentary processes, deposits, and landforms. Calculated using CRYOCHEM, liquids on Titan should exhibit a counter-intuitive behavior where density increases with temperature but decreases with pressure, unless the temperature falls below 89.6 K. For warmer temperatures, the surface liquid of seas should flow toward the hottest spot; return flow may occur beneath the surface. Methane-rich liquid flowing southward from one interconnected northern sea to another will evaporate methane and concentrate ethane and other heavy hydrocarbons. In the north polar and circumpolar regions, a south-flowing river entering a sea from cold northerly uplands will inject a buoyant plume of low-density methane-rich liquid into the sea, unless the liquid at the inlet is heavily charged with dense solid phases or unless the lake is colder than 89.6 K. Generally north of (colder than) the seasonally shifting 89.6K transition (possible during the winter precisely when river discharges are high), a different behavior exists, whereby cold and methane-rich liquid forms denser liquids and flows across the bottom of the sea—possibly forming sub-sea channels as observed at Ligeia Mare. If the river carries clastic sediment denser than the methane liquid, the solids will undergo Stokes settling of the coarser fractions during periods of high river discharge, leaving the finest clastic fraction to undergo slow pelagic sedimentation throughout the year. From late spring to late summer, methane undergoes net evaporation from the sea, and solid organics that were saturated during the winter are likely to precipitate once warm weather starts. Hence, varves in Titan's seas are apt to consist of annual cycles of (1) winter: coarse clastics, (2) all dry season: fine-grained clastics, and (3) summer: evaporites. As Titan undergoes 'Milankovic' type variations in rotational obliquity and Saturn's orbital eccentricity, the circumpolar climate and annual range of the seasonal cycle will change, forcing responses in rainfall rates, erosion rates, and the composition of lakes and seas. Thus, sediment deposit sequences—layered organic rock strata—in the circumpolar regions will record past climate changes due to long-term cycles as well as annual periodicity.

  2. Diseases and parasites of the sea lamprey, Petromyzon marinus, in the Lake Huron basin

    USGS Publications Warehouse

    McLain, Alberton L.

    1952-01-01

    Sea lampreys from the Lake Huron basin carried no external parasites and showed a fairly low degree of infection by internal parasites. The material examined represented three life-history stages of the sea lamprey. Recently transformed downstream migrants (215 specimens) harbored only nematodes belonging to the genus Camallanus. The percentage of infection was 2.3. Active feeders from the lake (29 lampreys) revealed the highest degree of parasitism (31.0 percent) with the following parasites present: Echinorhynchus coregoni Linkins; Triaenophorus crasses Forel; and Camallanus sp. Among the 257 sexually mature upstream migrants (14.8 percent infected) Echinorhynchus coregoni and E. leidyi Van Cleave were the most common. Only occasional nematodes and cestodes were found, which fact indicates a failure of the lamprey to carry these parasites to the end of its natural life. Of the parasites observed, only the nematodes gave evidence of serious damage to the host. The study suggests that the role played by parasites in the natural control of the sea lamprey in its new habitat in the upper Great Lakes is of minor importance.

  3. History told from the depths of Lake Champlai: 1992-1993 Fort Ticonderoga-Mount Independence submerged cultural resource survey 

    E-print Network

    McLaughlin, Scott Arthur

    2000-01-01

    HISTORY TOLD FROM THE DEPTHS OF LAKE CHAMPLAIN: 1992-1993 FORT TICONDEROGA-MOUNT INDEPENDENCE SUBMERGED CULTURAL RESOURCE SURVEY Volume I A Thesis SCOTT ARTHUR McLAUGHLIN Submitted to the Office of Graduate Studies of Texas A8dlll University... in partial fulfillment of the requirements for the degree of MASTER OF ARTS Maior Subtect. Anthropology HISTORY TOLD FROM THE DEPTHS OF LAKE CHAMPLAIN: 1992-1993 FORT TICONDEROGA-MOUNT INDEPENDENCE SUBMERGED CULTURAL RESOURCE SURVEY Volume( A Thesis...

  4. Potential relation between equatorial sea surface temperatures and historic water level variability for Lake Turkana, Kenya

    NASA Astrophysics Data System (ADS)

    Bloszies, Chris; Forman, Steven L.

    2015-01-01

    Water level in Lake Turkana, Kenya in the past ca. 150 years is controlled primarily from the biannual passage of the East and West African Monsoon, with rainfall volume related partially to sea surface temperatures (SSTs) in the Western Indian and East Atlantic oceans. Empirical orthogonal function analyses show significant correlation between Eastern Atlantic or Western Indian SSTs and lake level anomalies, with the first mode accounting for 66% and 55% of the variability. The primary geographic loadings are consistent with a Gulf of Guinea moisture source and positive Indian Ocean Dipole (IOD) state. The second mode explains 10% of variability, and reflects the westward extension of an Indian Ocean cool pool, potentially indicative of a normal to a negative IOD state. There is significant spatial correlation between basin rainfall anomalies associated with Eastern Atlantic SSTs and a low in the continental divide between the Kenyan and the Ethiopian Highlands, which is a passage for moisture from the Congo Basin. Linear regression analysis with Bootstrap sampling and Monte Carlo simulations define numeric relations between Western Indian and Eastern Atlantic SSTs and lake level change for AD 1992-2013. The monthly and yearly lake level reconstructions based on this numeric analysis capture the decadal-scale variability and the 15 m drop in water level in the early 20th century. Meter-scale variability in lake level since ca. AD 1930 is associated with precipitation sourced from the Western Indian Ocean with IOD variability, whereas the 15 m drop in water level in the early 20th century may reflect a profound decrease in moisture from Atlantic/Congo Basin source. These numerical solutions are poised to reconstruct water level variations in the past ca. 300 years for Lake Turkana with new proxy records of SSTs from the Western Indian Ocean and the Gulf of Guinea.

  5. Vermont Water Resources and Lake Studies Center Annual Technical Report

    E-print Network

    and extent of blooms of blue-green algae in Lake Champlain and other Vermont lakes. Researchers are using in the Northeastern U.S. American Geophysical Union, Fall Meeting, December, San Francisco, CA. 3. Wemple, B., J in the Northeastern U.S.: preliminary findings from a field study (poster). Vermont EPSCoR Program, Annual Meeting

  6. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation

    NASA Astrophysics Data System (ADS)

    Yakimov, Michail M.; La Cono, Violetta; Slepak, Vladlen Z.; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S.; Rojo, David; Barbas, Coral; Golyshina, Olga V.; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

    2013-12-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [14C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life.

  7. Microbial life in the Lake Medee, the largest deep-sea salt-saturated formation.

    PubMed

    Yakimov, Michail M; La Cono, Violetta; Slepak, Vladlen Z; La Spada, Gina; Arcadi, Erika; Messina, Enzo; Borghini, Mireno; Monticelli, Luis S; Rojo, David; Barbas, Coral; Golyshina, Olga V; Ferrer, Manuel; Golyshin, Peter N; Giuliano, Laura

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [(14)C]-assimilation, showed that these organisms at least partially rely on reductive cleavage of osmoprotectant glycine betaine and are engaged in trophic cooperation. These findings provide novel insights into how prokaryotic communities can adapt to salt-saturated conditions and sustain active metabolism at the thermodynamic edge of life. PMID:24352146

  8. Hypersaline brine diagenesis and evolution in the Dead Sea - Lake Lisan system (Israel)

    SciTech Connect

    Katz, A.; Kolodny, N. (Hebrew Univ., Jerusalem (Israel))

    1989-01-01

    Water soluble salts were extracted from 57 aragonite and detrital laminae, sampled from the Pleistocene Lake Lisan sediments. The solutions and solids were analyzed for Ca, Mg, Na, K, Sr, Cl, SO{sub 4} and bicarbonate. Average Na/Cl, Mg/Ca, Sr/Ca, Mg/Cl, Ca/Cl, Sr/Cl, K/Cl, K/Na, and K/Mg ratios, calculated for seven stratigraphic elevations in the Lisan column, indicate that the Dead Sea rift sediment/brine system has remained practically closed for 70,000 years. The soluble salts reflect both the hydrologic evolution of the lake as well as diagenetic processes. Mg/Ca ratios systematically decrease in younger sediments, and this decline is accompanied by a 1.5-4 fold Sr enrichment in aragonite solubles relative to salts extracted from detrital laminae. The major process responsible for these observations is dolomitization of Sr-rich aragonite by interstitial brine. Diagenesis was triggered by slow desiccation of the lakes sediments after the Lisan waters started to recede due to a change in climate. Very sharp chemical gradients, which developed in the sediments after deposition, have been preserved because further diagenesis was quenched by the advancing dry-out. H{sub 2}O-loss by evaporation induced diffusional migration of Na and Cl from aragonite laminae into adjacent detrital layers. This lowered the Na/Cl ratio in the aragonite and raised it in the detritus relative to the initial (Dead Sea) Na/Cl ratio of 0.26. The early Lisan brine was similar in its chemical composition and total salinity to that of the present Dead Sea.

  9. The sterile-male-release technique in Great Lakes sea lamprey management

    USGS Publications Warehouse

    Twohey, M.B.; Heinrich, J.W.; Seelye, J.G.; Fredricks, K.T.; Bergstedt, R.A.; Kaye, C.A.; Scholefield, R.J.; McDonald, R.B.; Christie, G.C.

    2003-01-01

    The implementation of a sterile-male-release technique from 1991 through 1999 and evaluation of its effectiveness in the Great Lakes sea lamprey (Petromyzon marinus) management program is reviewed. Male sea lampreys were injected with the chemosterilant bisazir (P,P-bis(1-aziridinyl)-N- methylphosphinothioic amide) using a robotic device. Quality assurance testing indicated the device delivered a consistent and effective dose of bisazir. Viability of embryos in an untreated control group was 64% compared to 1% in a treatment group. A task force developed nine hypotheses to guide implementation and evaluation of the technique. An annual average of 26,000 male sea lampreys was harvested from as many as 17 Great Lakes tributaries for use in the technique. An annual average of 16,100 sterilized males was released into 33 tributaries of Lake Superior to achieve a theoretical 59% reduction in larval production during 1991 to 1996. The average number of sterile males released in the St. Marys River increased from 4,000 during 1991 to 1996 to 20,100 during 1997 to 1999. The theoretical reduction in reproduction when combined with trapping was 57% during 1991 to 1996 and 86% during 1997 to 1999. Evaluation studies demonstrated that sterilized males were competitive and reduced production of larvae in streams. Field studies and simulation models suggest reductions in reproduction will result in fewer recruits, but there is risk of periodic high recruitment events independent of sterile-male release. Strategies to reduce reproduction will be most reliable when low densities of reproducing females are achieved. Expansion of the technique is limited by access to additional males for sterilization. Sterile-male release and other alternative controls are important in delivering integrated pest management and in reducing reliance on pesticides.

  10. The sterile-male-release technique in Great Lakes sea lamprey management

    USGS Publications Warehouse

    Twohey, Michael B.; Heinrich, John W.; Seelye, James G.; Fredricks, Kim T.; Bergstedt, Roger A.; Kaye, Cheryl A.; Scholefield, Ron J.; McDonald, Rodney B.; Christie, Gavin C.

    2003-01-01

    The implementation of a sterile-male-release technique from 1991 through 1999 and evaluation of its effectiveness in the Great Lakes sea lamprey (Petromyzon marinus) management program is reviewed. Male sea lampreys were injected with the chemosterilant bisazir (P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide) using a robotic device. Quality assurance testing indicated the device delivered a consistent and effective dose of bisazir. Viability of embryos in an untreated control group was 64% compared to 1% in a treatment group. A task force developed nine hypotheses to guide implementation and evaluation of the technique. An annual average of 26,000 male sea lampreys was harvested from as many as 17 Great Lakes tributaries for use in the technique. An annual average of 16,100 sterilized males was released into 33 tributaries of Lake Superior to achieve a theoretical 59% reduction in larval production during 1991 to 1996. The average number of sterile males released in the St. Marys River increased from 4,000 during 1991 to 1996 to 20,100 during 1997 to 1999. The theoretical reduction in reproduction when combined with trapping was 57% during 1991 to 1996 and 86% during 1997 to 1999. Evaluation studies demonstrated that sterilized males were competitive and reduced production of larvae in streams. Field studies and simulation models suggest reductions in reproduction will result in fewer recruits, but there is risk of periodic high recruitment events independent of sterile-male release. Strategies to reduce reproduction will be most reliable when low densities of reproducing females are achieved. Expansion of the technique is limited by access to additional males for sterilization. Sterile-male release and other alternative controls are important in delivering integrated pest management and in reducing reliance on pesticides.

  11. Classification of sea lamprey (Petromyzon marinus) attack marks on Great Lakes lake trout (Salvelinus namaycush)

    USGS Publications Warehouse

    King, Everett Louis, Jr.

    1980-01-01

    Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.

  12. Evolution of Titan's Lakes and Seas: Insights from Recent Infrared Observations

    NASA Astrophysics Data System (ADS)

    Sotin, C.; Seignovert, B.; Lawrence, K.; Barnes, J. W.; Brown, R. H.; Hayes, A.; Le Mouelic, S.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P. D.

    2013-12-01

    Titan's North Pole has been illuminated since the spring equinox in August 2009, allowing optical remote sensing instruments to acquire images of the lakes and seas that were discovered by the radar instrument earlier in the Cassini mission [1]. The illumination geometry continually improves with the incidence angle decreasing to its minimum at the summer solstice in 2017. Combined with highly inclined flybys that allow for small values of the emission angle, the 2013 observations are much less affected by the haze scattering because the optical path through the atmosphere is much shorter. The Visual and Infrared Mapping Spectrometer (VIMS) can observe Titan's surface in seven infrared atmospheric windows between 0.96- and 5-?m. This study describes observations acquired during the recent T93 flyby on July 26, 2013. The footprint ranges from 10 km/pixel to 3 km/pixel. Maps of the three large seas (Ligeia Mare, Punga Mare, and Kraken Mare) at seven different wavelengths are being constructed and a mosaic of the lake area is being assembled. Ligeia Mare was previously imaged by the VIMS in June 2010 [2]. A preliminary analysis of the 2-?m map suggests that the shoreline has not evolved since 2010. The shape of the 2- ?m atmospheric window will be compared between the two images and between the mare and the shore to investigate whether liquid ethane is present as is the case on Ontario lacus [3]. The lake area located between 0 and 90W was imaged with a resolution that allows comparison with the radar images. A preliminary comparison between the two data sets shows a very strong correlation. One part of Punga mare and a lake known as Kivu lacus were acquired on the same image. The northeastern part of Punga Mare seems entailed by a river network. No connections between Punga mare and Kivu lacus are observed on the VIMS image. Kivu lacus seems to lie in the center of a circular depression whose limit is bright at 2-?m. Equipotential maps are built from the topographic information obtained by the radar team [4] and the gravity potential determined by the Radio Science team [5]. As already determined [6], the topographic polar radius is smaller than the equipotential polar radius of an ellipsoid having the same volume. The three seas are indeed located in the depressions where the value of the gravitational potential is largest. On the other hand, the correlation is less clear with the lakes that seem to sit at higher elevation. If confirmed, this observation suggests that a putative subsurface connection between the lakes and the seas would drain out the lakes. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Stofan, E.R. et al. (2007) Nature 445, 61-64 [2] Sotin C. et al. (2012) Icarus 221, 768-786 [3]Brown R.H. et al. (2008) Nature 454, 607-609 [4] Lorenz R.D. (2013) Icarus 225, 367-377 [5] Iess L. et al. (2012) Science 337, 457-459 [6] Zebker H.A. (2009) Science 324, 921-923.

  13. Compensatory mechanisms in Great Lakes sea lamprey populations: Implications for alternative control strategies

    USGS Publications Warehouse

    Jones, M.L.; Bergstedt, R.A.; Twohey, M.B.; Fodale, M.F.; Cuddy, D.W.; Slade, J.W.

    2003-01-01

    Compensatory mechanisms are demographic processes that tend to increase population growth rates at lower population density. These processes will tend to reduce the effectiveness of actions that use controls on reproductive success to suppress sea lamprey (Petromyzon marinus), an economically important pest in the Great Lakes. Historical evidence for compensatory mechanisms in sea lamprey populations was reviewed, and revealed: (1) strong evidence for shifts in sex ratios as sea lamprey abundance was reduced in the early years of the control program; (2) weak and equivocal evidence for increased growth rates of sea lamprey cohorts re-colonizing streams following a lampricide treatment; and (3) suggestions of other compensatory processes, such as earlier ages at metamorphosis, but with little empirical evidence. Larval size distribution data for cohorts in the first and second years following a lampricide treatment (26 pairs of cohorts in 20 streams) was analyzed and did not indicate a consistent pattern of more rapid growth of the first colonizing cohort (only 11 of 33 cases). To test for compensation between spawning and age-1 in sea lamprey populations, data were analyzed for 49 stream-years for which spawning female abundance was known and age-1 abundance was estimated in the following year. A fit of these data to a Ricker stock-recruitment function showed evidence for compensation, measured as reduced survival to age 1 at higher abundance of spawning females. More obvious, however, was a large amount of density-independent variation in survival, which tends to mask evidence for compensatory survival. The results were applied to a simple model that simulates sea lamprey populations and their control in a hypothetical lake. Control strategies that targeted reproductive success performed far less well than comparable strategies that targeted larval populations, because density-independent recruitment variation leads to occasional strong year classes even when spawner abundance is reduced to low levels through alternative control. It is concluded that further study of recruitment variation in lamprey populations is critical to rationalizing alternative controls that target reproductive success, and that recruitment variation needs to be incorporated into models used to evaluate sea lamprey control options.

  14. Compensatory mechanisms in Great Lakes sea lamprey populations: implications for alternative control strategies

    USGS Publications Warehouse

    Jones, Michael L.; Bergstedt, R.A.; Twohey, Michael B.; Fodale, Michael F.; Cuddy, Douglas W.; Slade, Jeffrey W.

    2003-01-01

    Compensatory mechanisms are demographic processes that tend to increase population growth rates at lower population density. These processes will tend to reduce the effectiveness of actions that use controls on reproductive success to suppress sea lamprey (Petromyzon marinus), an economically important pest in the Great Lakes. Historical evidence for compensatory mechanisms in sea lamprey populations was reviewed, and revealed: (1) strong evidence for shifts in sex ratios as sea lamprey abundance was reduced in the early years of the control program; (2) weak and equivocal evidence for increased growth rates of sea lamprey cohorts re-colonizing streams following a lampricide treatment; and (3) suggestions of other compensatory processes, such as earlier ages at metamorphosis, but with little empirical evidence. Larval size distribution data for cohorts in the first and second years following a lampricide treatment (26 pairs of cohorts in 20 streams) was analyzed and did not indicate a consistent pattern of more rapid growth of the first colonizing cohort (only 11 of 33 cases). To test for compensation between spawning and age-1 in sea lamprey populations, data were analyzed for 49 stream-years for which spawning female abundance was known and age-1 abundance was estimated in the following year. A fit of these data to a Ricker stock-recruitment function showed evidence for compensation, measured as reduced survival to age 1 at higher abundance of spawning females. More obvious, however, was a large amount of density-independent variation in survival, which tends to mask evidence for compensatory survival. The results were applied to a simple model that simulates sea lamprey populations and their control in a hypothetical lake. Control strategies that targeted reproductive success performed far less well than comparable strategies that targeted larval populations, because density-independent recruitment variation leads to occasional strong year classes even when spawner abundance is reduced to low levels through alternative control. It is concluded that further study of recruitment variation in lamprey populations is critical to rationalizing alternative controls that target reproductive success, and that recruitment variation needs to be incorporated into models used to evaluate sea lamprey control options.

  15. Changes in mortality of lake trout (Salvelinus namaycush) in Michigan waters of Lake Superior in relation to sea lamprey (Petromyzon marinus) predation, 1968-78

    USGS Publications Warehouse

    Pycha, Richard L.

    1980-01-01

    Total mortality rates of lake trout (Salvelinus namaycush) of age VII and older from eastern Lake Superior were estimated from catch curves of age distributions each year in 1968-78. The instantaneous rate of total mortality Z varied from 0.62 to 2.31 in close synchrony with sea lamprey (Petromyzon marinus) wounding rates on lake trout. The regression of transformed Z on the index of lamprey wounding accounted for over 89% of the variation in lake trout mortality (rA? = 0.893). An iterative method of estimating rates of exploitation u, instantaneous rates of fishing mortality F, K (a constant relating sample catch per unit effort to population size), instantaneous normal natural mortality rate M, and instantaneous rate of mortality due to sea lamprey predation L from the sample catch per unit effort and total catch by the fishery is presented. A second method using the results of a 1970-71 tagging study to estimate the mean F in 1970-77 yielded closely similar results to the above and is presented as corroboration. The estimates of u, F, and M appear to be reasonable. F ranged from 0.17 in 1974 to 0.42 in 1969 and M was estimated at 0.26. L varied from 0.21 in 1974 to 1.70 in 1968. Management implications of various policies concerning sea lamprey control, exploitation, and stocking are discussed.

  16. Techniques and methods for estimating abundance of larval and metamorphosed sea lampreys in Great Lakes tributaries, 1995 to 2001

    USGS Publications Warehouse

    Slade, Jeffrey W.; Adams, Jean V.; Christie, Gavin C.; Cuddy, Douglas W.; Fodale, Michael F.; Heinrich, John W.; Quinlan, Henry R.; Weise, Jerry G.; Weisser, John W.; Young, Robert J.

    2003-01-01

    Before 1995, Great Lakes streams were selected for lampricide treatment based primarily on qualitative measures of the relative abundance of larval sea lampreys, Petromyzon marinus. New integrated pest management approaches required standardized quantitative measures of sea lamprey. This paper evaluates historical larval assessment techniques and data and describes how new standardized methods for estimating abundance of larval and metamorphosed sea lampreys were developed and implemented. These new methods have been used to estimate larval and metamorphosed sea lamprey abundance in about 100 Great Lakes streams annually and to rank them for lampricide treatment since 1995. Implementation of these methods has provided a quantitative means of selecting streams for treatment based on treatment cost and estimated production of metamorphosed sea lampreys, provided managers with a tool to estimate potential recruitment of sea lampreys to the Great Lakes and the ability to measure the potential consequences of not treating streams, resulting in a more justifiable allocation of resources. The empirical data produced can also be used to simulate the impacts of various control scenarios.

  17. Oxygen isotope composition of water and snow-ice cover of isolated lakes at various stages of separation from the White Sea

    NASA Astrophysics Data System (ADS)

    Lisitzin, A. P.; Vasil'chuk, Yu. K.; Shevchenko, V. P.; Budantseva, N. A.; Krasnova, E. D.; Pantyulin, A. N.; Filippov, A. S.; Chizhova, Ju. N.

    2013-04-01

    This study aimed to analyze the oxygen isotope composition of water, ice, and snow in water bodies isolated from the White Sea and to identify the structural peculiarities of these pools during the winter period. The studies were performed during early spring in Kandalaksha Bay of the White Sea, in Velikaya Salma Strait and in Rugoserskaya Inlet. The studied water bodies differ in their degree of isolation from the sea. In particular, Ermolinskaya Inlet has normal water exchange with the sea; the Lake on Zelenyi Cape represents the first stage of isolation; i. e., it has permanent water exchange with the sea by the tide. Kislo-Sladkoe Lake receives sea water from time to time. Trekhtsvetnoe Lake is totally isolated from the sea and is a typical meromictic lake. Finally, Nizhnee Ershovskoe Lake exhibits some features of a saline water body. The oxygen isotope profile of the water column in Trekhtsvetnoe Lake allows defining three layers; this lake may be called typically meromictic. The oxygen isotope profile of the water column in Kislo-Sladkoe Lake is even from the surface to the bottom. The variability of ?18O is minor in Lake on Zelenyi Cape. A surface layer (0-1 m) exists in Nizhnee Ershovskoe Lake, and the oxygen isotope variability is well pronounced. Deeper, where the freshwater dominates, the values of ?18Îvary insignificantly disregarding the water depth and temperature. This fresh water lake is not affected by the seawater and is not stratified according to the isotope profile. It is found that applying the values of ?18Î and profiles of temperature and salinity may appear as an effective method in defining the water sources feeding the water bodies isolated from the sea environment.

  18. Classifying sea lamprey marks on Great Lakes lake trout: Observer agreement, evidence on healing times between classes, and recommendations for reporting of marking statistics

    USGS Publications Warehouse

    Ebener, M.P.; Bence, J.R.; Bergstedt, R.A.; Mullett, K.M.

    2003-01-01

    In 1997 and 1998 two workshops were held to evaluate how consistent observers were at classifying sea lamprey (Petromyzon marinus) marks on Great Lakes lake trout (Salvelinus namaycush) as described in the King classification system. Two trials were held at each workshop, with group discussion between trials. Variation in counting and classifying marks was considerable, such that reporting rates for A1-A3 marks varied two to three-fold among observers of the same lake trout. Observer variation was greater for classification of healing or healed marks than for fresh marks. The workshops highlighted, as causes for inconsistent mark classification, both departures from the accepted protocol for classifying marks by some agencies, and differences in how sliding and multiple marks were interpreted. Group discussions led to greater agreement in classifying marks. We recommend ways to improve the reliability of marking statistics, including the use of a dichotomous key to classify marks. Laboratory data show that healing times of marks on lake trout were much longer at 4??C and 1??C than at 10??C and varied greatly among individuals. Reported A1-A3 and B1-B3 marks observed in late summer and fall collections likely result from a mixture of attacks by two year classes of sea lamprey. It is likely that a substantial but highly uncertain proportion of attacks that occur in late summer and fall lead to marks that are classified as A1-A3 the next spring. We recommend additional research on mark stage duration.

  19. [Anoxygenic phototrophic bacteria of the Kislo-Sladkoe Stratified Lake (White Sea, Kandalaksha Bay)].

    PubMed

    2014-01-01

    The community of anoxygenic phototrophic bacteria (APB) in the water column of the Kislo-Sladkoe stratified lake recently isolated from the sea (White Sea, Kandalaksha Bay) was investigated in September 2010. The water of the sulfide-rich zone was greenish-brown due to intense development of green sulfur bacteria (GSB). Nine APB strains were isolated from the water samples: three belonging to GSB, five, to purple sulfur bacteria (PSB), and one, to purple nonsulfur bacteria (PNB). GSB predominated in the phototrophic community of the chemocline. Unexpectedly, two morphologically different green-colored GSB strains were found to be phylogenetically identical and related to the brown-colored @Chlorobium phaeovibrioides (99% similarity according to the 16S rRNA gene sequencing). Homology to the closest green-colored species (Chlorobium luteolum) was 98%. Two morphologically and physiologically similar PSB strains (TcrPS10 and AmPS10) had rounded cells containing okenonokenonee and gas vesicles. According to the 16S rRNA gene sequencing, these strains were most closely related (99%) to two different Thiocapsa species: Tca. marina (containing okenonokenonee and no gas vesicles) and Tca. rosea (containing spirilloxanthin and gas vesicles). The remaining isolates of purple bacteria were similar to the already described APB species. PMID:25513019

  20. [Anoxygenic phototrophic bacteria of the Kislo-Sladkoe Stratified Lake (White Sea, Kandalaksha Bay)].

    PubMed

    Lunina, O N; Savvichev, A S; Kuznetsov, B B; Pimenov, N V; Gorlenko, V M

    2014-01-01

    The community of anoxygenic phototrophic bacteria (APB) in the water column of the Kislo-Sladkoe stratified lake recently isolated from the sea (White Sea, Kandalaksha Bay) was investigated in September 2010. The water of the sulfide-rich zone was greenish-brown due to intense development of green sulfur bacteria (GSB). Nine APB strains were isolated from the water samples: three belonging to GSB, five, to purple sulfur bacteria (PSB), and one, to purple nonsulfur bacteria (PNB). GSB predominated in the phototrophic community of the chemocline. Unexpectedly, two morphologically different green-colored GSB strains were found to be phylogenetically identical and related to the brown-colored @Chlorobium phaeovibrioides (99% similarity according to the 16S rRNA gene sequencing). Homology to the closest green-colored species (Chlorobium luteolum) was 98%. Two morphologically and physiologically similar PSB strains (TcrPS10 and AmPS10) had rounded cells containing okenonokenonee and gas vesicles. According to the 16S rRNA gene sequencing, these strains were most closely related (99%) to two different Thiocapsa species: Tca. marina (containing okenonokenonee and no gas vesicles) and Tca. rosea (containing spirilloxanthin and gas vesicles). The remaining isolates of purple bacteria were similar to the already described APB species. PMID:25436251

  1. Lake

    ERIC Educational Resources Information Center

    Wien, Carol Anne

    2008-01-01

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

  2. Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

    PubMed Central

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  3. Classifying sea lamprey marks on Great Lakes lake trout: observer agreement, evidence on healing times between classes and recommendations for reporting of marking statistics

    USGS Publications Warehouse

    Ebener, Mark P.; Bence, James R.; Bergstedt, Roger A.; Mullet, Katherine M.

    2003-01-01

    In 1997 and 1998 two workshops were held to evaluate how consistent observers were at classifying sea lamprey (Petromyzon marinus) marks on Great Lakes lake trout (Salvelinus namaycush) as described in the King classification system. Two trials were held at each workshop, with group discussion between trials. Variation in counting and classifying marks was considerable, such that reporting rates for A1-A3 marks varied two to three-fold among observers of the same lake trout. Observer variation was greater for classification of healing or healed marks than for fresh marks. The workshops highlighted, as causes for inconsistent mark classification, both departures from the accepted protocol for classifying marks by some agencies, and differences in how sliding and multiple marks were interpreted. Group discussions led to greater agreement in classifying marks. We recommend ways to improve the reliability of marking statistics, including the use of a dichotomous key to classify marks. Laboratory data show that healing times of marks on lake trout were much longer at 4A?C and 1A?C than at 10A?C and varied greatly among individuals. Reported A1-A3 and B1-B3 marks observed in late summer and fall collections likely result from a mixture of attacks by two year classes of sea lamprey. It is likely that a substantial but highly uncertain proportion of attacks that occur in late summer and fall lead to marks that are classified as A1-A3 the next spring. We recommend additional research on mark stage duration.

  4. Beryllium isotopes as tracers of Lake Lisan (last Glacial Dead Sea) hydrology and the Laschamp geomagnetic excursion

    NASA Astrophysics Data System (ADS)

    Belmaker, Reuven; Stein, Mordechai; Beer, Jürg; Christl, Marcus; Fink, David; Lazar, Boaz

    2014-08-01

    The content of the cosmogenic isotope 10Be (t1/2=1.39 Ma) in lacustrine sediments that deposit in lakes with a large watershed is susceptible to both climate and cosmogenic production rate variations. In order to distinguish between these two controls, we measured 10Be and major elements in several sections of the annually laminated sediments of the Lake Lisan (the last Glacial precursor of the Dead Sea) that are composed of detrital sediments and primary (evaporitic) aragonites. The sections were selected to represent regional hydrology and climate as reflected by different lake configurations (level rise, drop and high-stands) and rapid change in the 10Be production rate during the Laschamp geomagnetic excursion. Since the short-lived cosmogenic “sister” of 10Be, 7Be (t1/2=53.3 d) has virtually no recycled component, the recycled 10Be in Lake Lisan detrital sediments was evaluated by measuring 7Be in their modern equivalents: modern flood suspended matter, dust and mud cracks. Our results demonstrate that although the recycled 10Be component is significant, secular variations in the 10Be concentration in Lake Lisan sediments correlate with hydrological variations and geomagnetic excursions. During periods of moderate variations in 10Be production rate, the 10Be concentration in the Lisan detrital sediments positively correlates with lake level, Al + Fe content and the (Al + Fe)/(Ca + Mg) ratio. These correlations suggest that the 10Be is adsorbed on the fine silicate component (probably clays) of the detrital laminae. The fine silicates together with carbonates were transported to Dead Sea drainage basin mainly as airborne dust that after a short residence time was washed into Lake Lisan as flood suspended matter. We suggest that preferential dissolution of carbonates in the flood suspended matter concentrated the residual fine component leading to the positive correlation between 10Be and the (Al + Fe)/(Ca + Mg) ratio. During periods of increased water discharge more carbonates were dissolved and hence the 10Be concentration in the detrital laminae increased. During periods of rapid increase in the 10Be production rate (e.g. the Laschamp excursion), 10Be showed a ?2 fold increase, beyond the above-mentioned correlations (lake levels and Al + Fe contents). This observation suggests that Lake Lisan can serve as a potential high-resolution archive of 10Be production rate variations during periods of geomagnetic excursions.

  5. "They Would Not Take Me There" People, Places, and Stories from Champlain's Travels in Canada 1603-1616

    E-print Network

    Hermann, Michael; Pearce, Margaret Wickens

    2010-08-01

    Cartographic Perspectives, Number 66, Fall 2010 “They Would Not Take Me There” – Hermann & Pearce | 41 “They Would Not Take Me There” People, Places, and Stories from Champlain’s Travels in Canada 1603–1616 Michael Hermann1 | mike..., which embeds a legend based on type and color, and is read as narrative instead of a conventional abstract legend. It ends with the introductory statement by Champlain, as he first sights land in 1603. From here, the reader is well positioned...

  6. Heavy metal-antibiotic resistant bacteria in a lake recreational area

    Microsoft Academic Search

    Robert E. Sjogren; Jennifer Port

    1981-01-01

    We undertook this study to determine the impact of urbanization on the microbial content of waters of a major recreational area of Lake Champlain. We followed changes in the numbers of total coliforms, fecal coliforms, fecal streptococci, and ascertained resistance of coliforms to heavy metals and antibiotics. We determined the distribution of these bacterial indicators of pollution by examining water

  7. Long-term changes in cyanobacteria populations in lake kinneret (sea of galilee), Israel: an eco-physiological outlook.

    PubMed

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-01-01

    The long-term record of cyanobacteria abundance in Lake Kinneret (Sea of Galilee), Israel, demonstrates changes in cyanobacteria abundance and composition in the last five decades. New invasive species of the order Nostocales (Aphanizomenon ovalisporum and Cylindrospermopsis raciborskii) became part of the annual phytoplankton assemblage during summer-autumn. Concomitantly, bloom events of Microcystis sp. (Chroococcales) during winter-spring intensified. These changes in cyanobacteria pattern may be partly attributed to the management policy in Lake Kinneret's vicinity and watershed aimed to reduce effluent discharge to the lake and partly to climate changes in the region; i.e., increased water column temperature, less wind and reduced precipitation. The gradual decrease in the concentration of total and dissolved phosphorus and total and dissolved nitrogen and an increase in alkalinity, pH and salinity, combined with the physiological features of cyanobacteria, probably contributed to the success of cyanobacteria. The data presented here indicate that the trend of the continuous decline of nutrients may not be sufficient to reduce and to control the abundance and proliferation of toxic and non-toxic cyanobacteria. PMID:25664964

  8. Quantification of a male sea lamprey pheromone in tributaries of Laurentian Great Lakes by liquid chromatography-tandem mass spectrometry

    USGS Publications Warehouse

    Xi, X.; Johnson, N.S.; Brant, C.O.; Yun, S.-S.; Chambers, K.L.; Jones, A.D.; Li, W.

    2011-01-01

    We developed an assay for measuring 7?,12?,24-trihydroxy-5a-cholan-3-one-24-sulfate (3kPZS), a mating pheromone released by male sea lampreys (Petromyzon marinus), at low picomolar concentrations in natural waters to assess the presence of invasive populations. 3kPZS was extracted from streamwater at a rate of recovery up to 90% using a single cation-exchange and reversed-phase mixed-mode cartridge, along with [2H5]3kPZS as an internal standard, and quantified using ultrahigh performance liquid chromatography-tandem mass spectrometry. The limit of detection was below 0.1 ng L–1 (210 fM), which was the lowest concentration tested. Intra- and interday coefficients of variation were between 0.3–11.6% and 4.8–9.8%, respectively, at 1 ng 3kPZS L–1 and 5 ng 3kPZS L–1. This assay was validated by repeat measurements of water samples from a stream spiked with synthesized 3kPZS to reach 4.74 ng L–1 or 0.24 ng L–1. We further verified the utility of this assay to detect spawning populations of lampreys; in the seven tributaries to the Laurentian Great Lakes sampled, 3kPZS concentrations were found to range between 0.15 and 2.85 ng L–1 during the spawning season in known sea lamprey infested segments and were not detectable in uninfested segments. The 3kPZS assay may be useful for the integrated management of sea lamprey, an invasive species in the Great Lakes where pheromone-based control and assessment techniques are desired.

  9. Tests of glacial rebound models for Fennoscandinavia based on instrumented sea- and lake-level records

    Microsoft Academic Search

    Kurt Lambeck; Catherine Smither; Martin Ekman

    1998-01-01

    Evidence for changing sea levels in northwestern Europe related to glacial rebound is found in both the geological record of the past millennia and in the instrumental records of the past two centuries. The latter records are of two types: records of sea-level change, primarily from the Baltic and the Gulfs of Finland and Bothnia, and records of the tilting

  10. An Assessment of Age Determination Methods for Great Lakes Larval Sea Lampreys

    Microsoft Academic Search

    Heather A. Dawson; Michael L. Jones; Kim T. Scribner; Stacy A. Gilmore

    2009-01-01

    Estimating the age composition and recruitment of populations of invasive sea lampreys Petromyzon marinus necessitates the validation and improvement of age assessment methods that rely on statoliths and length-frequency data. Determining age based on length-frequency distributions is subjective because of heterogeneity in the growth rates of larval sea lampreys (ammocoetes) within and across streams and the resulting overlap in lengths

  11. Passage of four teleost species prior to sea lamprey (Petromyzon marinus) migration in eight tributaries of Lake Superior, 1954 to 1979

    USGS Publications Warehouse

    Klingler, G.L.; Adams, J.V.; Heinrich, J.W.

    2003-01-01

    Seasonally operated barriers in rivers are used by the Great Lakes Fishery Commission to block adult sea lamprey (Petromyzon marinus) migrations, yet pass other fish during some part of the year. Knowledge of the overlap of spawning migrations of sea lampreys and other fish species are vital for the efficient operation of the Commission's barrier program. The migration of sea lamprey spawners was compared with the migration of four other fish species using trap captures at electric barriers on eight Lake Superior tributaries during 1954 to 1979. The passage of rainbow trout (Oncorhynchus mykiss), rainbow smelt (Osmerus mordax), longnose suckers (Catostomus catostomus), and white suckers (Catostomus commersoni) prior to the capture of sea lampreys was quantified as the proportion of the annual catch of each species. Average passage over all streams and years was smallest (5%) for longnose sucker and largest (21%) for rainbow smelt. Passage prior to first sea lamprey catch was significantly different among rivers for all four species and significantly different among years for rainbow trout. Much of the variability in annual passage was unexplained by river or year effects. It is suggested that stream-specific information on run times of sea lampreys and other fishes be used to define timing of seasonal barrier operations. If barrier operations are timed to block the entire sea lamprey spawning run, then fish passage devices are needed to pass rainbow trout, rainbow smelt, longnose suckers, and white suckers.

  12. Passage of four teleost species prior to sea lamprey (Petromyzon marinus) migration in eight tributaries of Lake Superior, 1954-1979

    USGS Publications Warehouse

    Klinger, Gregory L.; Adams, Jean V.; Heinrich, John W.

    2003-01-01

    Seasonally operated barriers in rivers are used by the Great Lakes Fishery Commission to block adult sea lamprey (Petromyzon marinus) migrations, yet pass other fish during some part of the year. Knowledge of the overlap of spawning migrations of sea lampreys and other fish species are vital for the efficient operation of the Commission's barrier program. The migration of sea lamprey spawners was compared with the migration of four other fish species using trap captures at electric barriers on eight Lake Superior tributaries during 1954 to 1979. The passage of rainbow trout (Oncorhynchus mykiss), rainbow smelt (Osmerus mordax), longnose suckers (Catostomus catostomus), and white suckers (Catostomus commersoni) prior to the capture of sea lampreys was quantified as the proportion of the annual catch of each species. Average passage over all streams and years was smallest (5%) for longnose sucker and largest (21%) for rainbow smelt. Passage prior to first sea lamprey catch was significantly different among rivers for all four species and significantly different among years for rainbow trout. Much of the variability in annual passage was unexplained by river or year effects. It is suggested that stream-specific information on run times of sea lampreys and other fishes be used to define timing of seasonal barrier operations. If barrier operations are timed to block the entire sea lamprey spawning run, then fish passage devices are needed to pass rainbow trout, rainbow smelt, longnose suckers, and white suckers.

  13. Trophic relations in two lakes from the Bulgarian Black Sea coast and possibilities for their restoration.

    PubMed

    Kalchev, R K; Pehllvanov, L Z; Beshkova, M B

    2002-01-01

    Based on quantitative data on nutrients, light penetration, phytoplankton, zooplankton and zoobenthos obtained in the period 1992-1994 the relations between trophic levels were studied by means of statistical analysis. The two lakes are distinguished by relatively high transfer efficiency between phytoplankton and zooplankton, which depends on the size distribution among zooplankton and percentage of blue-green algae. The bottom up influence seems to prevail over the top-down influence, water surface area and phosphorus load are large, and mean depth is more than 1 m. All this let us conclude that biomanipulation measures alone are not sufficient for a substantial lake restoration. PMID:12420960

  14. Fauna and flora in submarine early Holocene lake-marl deposits from the southwestern Baltic Sea

    Microsoft Academic Search

    Ole Bennike; Wolfram Lemke; Jørn Bo Jensen

    1998-01-01

    Studies of plant and animal macrofossils have been carried out on early-Holocene lake marls from the southwestern Baltic. The records have been dated to the interval from c. 8500 to 7800 14C years BP by correlating pollen assemblages to an onshore radiocarbon dated pollen diagram. The sediments contain from 5 to 81% carbonate, and only few macroscopic remains of wetland

  15. Colourful coexistence of red and green picocyanobacteria in lakes and seas

    Microsoft Academic Search

    Maayke Stomp; Jef Huisman; F. R. Pick; M. Laamanen; T. Haverkamp; Lucas J. Stal

    2007-01-01

    Hutchinson's paradox of the plankton inspired many studies on the mechanisms of species coexistence. Recent laboratory experiments showed that partitioning of white light allows stable coexistence of red and green picocyanobacteria. Here, we investigate to what extent these laboratory findings can be extrapolated to natural waters. We predict from a parameterized competition model that the underwater light colour of lakes

  16. Optimizing larval assessment to support sea lamprey control in the Great Lakes

    USGS Publications Warehouse

    Hansen, M.J.; Adams, J.V.; Cuddy, D.W.; Richards, J.M.; Fodale, M.F.; Larson, G.L.; Ollila, D.J.; Slade, J.W.; Steeves, T.B.; Young, R.J.; Zerrenner, A.

    2003-01-01

    Elements of the larval sea lamprey (Petromyzon marinus) assessment program that most strongly influence the chemical treatment program were analyzed, including selection of streams for larval surveys, allocation of sampling effort among stream reaches, allocation of sampling effort among habitat types, estimation of daily growth rates, and estimation of metamorphosis rates, to determine how uncertainty in each element influenced the stream selection program. First, the stream selection model based on current larval assessment sampling protocol significantly underestimated transforming sea lamprey abundance, transforming sea lampreys killed, and marginal costs per sea lamprey killed, compared to a protocol that included more years of data (especially for large streams). Second, larval density in streams varied significantly with Type-I habitat area, but not with total area or reach length. Third, the ratio of larval density between Type-I and Type-II habitat varied significantly among streams, and that the optimal allocation of sampling effort varied with the proportion of habitat types and variability of larval density within each habitat. Fourth, mean length varied significantly among streams and years. Last, size at metamorphosis varied more among years than within or among regions and that metamorphosis varied significantly among streams within regions. Study results indicate that: (1) the stream selection model should be used to identify streams with potentially high residual populations of larval sea lampreys; (2) larval sampling in Type-II habitat should be initiated in all streams by increasing sampling in Type-II habitat to 50% of the sampling effort in Type-I habitat; and (3) methods should be investigated to reduce uncertainty in estimates of sea lamprey production, with emphasis on those that reduce the uncertainty associated with larval length at the end of the growing season and those used to predict metamorphosis.

  17. Optimizing Larval Assessment to Support Sea Lamprey Control in the Great Lakes

    Microsoft Academic Search

    Michael J. Hansen; Jean V. Adams; Douglas W. Cuddy; Jessica M. Richards; Michael F. Fodale; Geraldine L. Larson; Dale J. Ollila; Jeffrey W. Slade; Todd B. Steeves; Robert J. Young; Adam Zerrenner

    2003-01-01

    Elements of the larval sea lamprey (Petromyzon marinus) assessment program that most strongly influence the chemical treatment program were analyzed, including selection of streams for larval surveys, allocation of sampling effort among stream reaches, allocation of sampling effort among habitat types, estimation of daily growth rates, and estimation of metamorphosis rates, to determine how uncertainty in each element influenced the

  18. Effects of wind trend and gustiness on the sea drag: Lake George study

    Microsoft Academic Search

    Alexander V. Babanin; Vladimir K. Makin

    2008-01-01

    The air-sea coupling is usually parameterized in terms of the drag coefficient C d , but the scatter of experimental data around such dependences is very significant and has not improved noticeably over some 30 years. In the paper, which is meant to be the first in a series, a complex approach to the problem is suggested. Multiple mechanisms, contributing

  19. Migration history of North Sea houting ( Coregonus oxyrinchus L.) caught in Lake IJsselmeer (The Netherlands) inferred from scale transects of 88 Sr: 44 Ca ratios

    Microsoft Academic Search

    Jost Borcherding; Carola Pickhardt; Hendrik V. Winter; J. Sabine Becker

    2008-01-01

    .  North Sea houting, Coregonus oxyrinchus, became extinct in the River Rhine in the 1940 s and was reintroduced in the 1990 s. To study the migration history of individuals,\\u000a the 88Sr:44Ca ratio of scales of 39 houting (10–44 cm TL) caught in Lake IJsselmeer was analysed using laser ablation inductively coupled\\u000a plasma mass spectrometry (LA-ICP-MS). Scales of houting inhabiting freshwater

  20. Variability in ice phenology on Great Bear Lake and Great Slave Lake, Northwest Territories, Canada, from SeaWinds\\/QuikSCAT: 2000–2006

    Microsoft Academic Search

    Stephen E. L. Howell; Laura C. Brown; Kyung-Kuk Kang; Claude R. Duguay

    2009-01-01

    The temporal evolution of the backscatter coefficient, sigma-nought (?°) from QuikSCAT was evaluated for monitoring ice phenology on Great Bear Lake (66°N, 121°W) and Great Slave Lake (61°40?N, 114°W), Northwest Territories, Canada. Results indicated that ?° from QuikSCAT can be used to detect melt onset, water clear of ice and freeze onset dates on both lakes. An ice phenology algorithm

  1. Great Lakes and Lake Effect Snow

    NSDL National Science Digital Library

    Lori Perkins

    1999-12-03

    Great Lakes and Lake Effect Snow. This animation is a dissolve between 2 different SeaWiFS images taken in 1999. One image is taken in the spring,April, and the second image is taken in the winter, December. The December 1999 image shows a traditional lake effect snow storm. This animation shows the difference between the seasons in the Great Lakes region.

  2. Lakes of the Huron basin: their record of runoff from the laurentide ice sheet

    NASA Astrophysics Data System (ADS)

    Michael Lewis, C. F.; Moore, Theodore C.; Rea, David K.; Dettman, David L.; Smith, Alison M.; Mayer, Larry A.

    The 189,000 km2 Huron basin is central in the catchment area of the present Laurentian Great Lakes that now drain via the St. Lawrence River to the North Atlantic Ocean. During deglaciation from 21-7.5 ka BP, and owing to the interactions of ice margin positions, crustal rebound and regional topography, this basin was much more widely connected hydrologically, draining by various routes to the Gulf of Mexico and Atlantic Ocean, and receiving overflows from lakes impounded north and west of the Great Lakes-Hudson Bay drainage divide. Early ice-marginal lakes formed by impoundment between the Laurentide Ice Sheet and the southern margin of the basin during recessions to interstadial positions at 15.5 and 13.2 ka BP. In each of these recessions, lake drainage was initially southward to the Mississippi River and Gulf of Mexico. In the first recession, drainage subsequently switched eastward along the ice margin to the North Atlantic Ocean. In the second recession, drainage continued southward through the Michigan basin, and later, eastward via the Ontario basin and Mohawk River valley to the North Atlantic Ocean. During the final retreat of ice in the Huron basin from 13 to 10 ka BP, proglacial lake drainage switched twice from the Michigan basin and the Mississippi River system to the North Atlantic via the Ontario basin and Mohawk River valley, finally diverting to the Champlain Sea in the St. Lawrence River valley at about 11.6 ka BP. New seismo- and litho-stratigraphic information with ostracode data from the offshore lacustrine sediments were integrated with the traditional data of shorelines, uplift histories of outlets, and radio-carbon-dated shallow-water evidence of transgressions and regressions to reconstruct the water level history and paleolimnological record for the northern Huron basin for the 11-7 ka BP period. Negative excursions in the ?18O isotopic composition of ostracodes and bivalves in southern Lake Michigan, southwestern Lake Huron and eastern Lake Erie indicate an influx of water from ice-marginal Lake Agassiz in central North America about 11 ka BP. A major decline in water levels of the Huron basin after 10.5 ka BP followed the high-level Main Lake Algonquin phase as ice receded and drainage was established through the North Bay area to Ottawa River valley. During the subsequent Mattawa-Stanley phase, the lake level history was dominated by fluctuations of tens of meters. Highstands of the earliest oscillations, whose origin is not clear, might be related to some of the well known Post Algonquin shorelines. After 9.6 ka BP, it is suggested that large inflows from Lake Agassiz and hydraulic damming in downstream outlets were the likely cause of the Lake Mattawa highstands. A lowstand at 9.3-9.1 ka BP occurred when these inflows were diverted, or impeded by an ice advance in the Nipigon basin area, while undiluted meltwater continued to enter the Huron basin. Assemblages and isotopic composition of the ostracode fauna indicate very dilute meltwater during the lowstands as late as 7.5 ka BP, and precipitation runoff with comparatively higher dissolved solids during the highstands. We speculate that the water composition of the Lake Mattawa highstands was dominated by the Agassiz inflows; by that time, much of Lake Agassiz was remote from ice-marginal environments, and the inflows were drawn from surface water of the southern sector of the lake, which was largely supplied by runoff and dissolved solids from the exposed land area of western Canada. Major inflows apparently ended about 8 ka BP, but northern proglacial lakes apparently continued as meltwater persisted in the Huron basin until about 7.5 ka BP. The cessation of major inflows initiated the final lowstand in the Huron basin and the present hydrological regime of local runoff.

  3. Heavy metal pollution status in surface sediments of Swan Lake lagoon and Rongcheng Bay in the northern Yellow Sea.

    PubMed

    Huang, Lili; Pu, Xinming; Pan, Jin-Fen; Wang, Bo

    2013-11-01

    The national 'Shandong Peninsula Blue Economic Zone Development Plan' compels the further understanding of the distribution and potential risk of metals pollution in the east coast of China, where the rapid economic and urban development have been taken off and metal pollution has become a noticeable problem. Surface sediments collected from the largest swan habitat in Asia, the Swan Lake lagoon and the surrounding coastal area in Rongcheng Bay in northern Yellow Sea, were analyzed for the total metal concentrations and chemical phase partitioning of five heavy metals (Cu, Zn, Pb, Cd, and Cr). Metal contents in the studied region have increased significantly in the past decade. The speciation analyzed by the sequential extraction showed that Zn and Cr were present dominantly in the residual fraction and thus of low bioavailability, while Cd, Pb and Cu were found mostly in the non-residual fraction thus of high potential availability, indicating significant anthropogenic sources. Among the five metals, Cd is the most outstanding pollutant and presents high risk, and half of the surface sediments in the studied region had a 21% probability of toxicity based on the mean Effect Range-Median Quotient. At some stations with comparable total metal contents, remarkably different non-residual fraction portions were determined, pointing out that site-specific risk assessment integrating speciation is crucial for better management practices of coastal sediments. PMID:23880240

  4. Late Pleistocene glacial and lake history of northwestern Russia EILIV LARSEN, KURT H. KJR, IGOR N. DEMIDOV, SVEND FUNDER, KARI GRSFJELD, MICHAEL

    E-print Network

    Ingólfsson, Ólafur

    a huge ice-dammed lake formed in the White Sea basin (the `White Sea Lake'), only now the outlet across marine down-draw that led to its rapid collapse. The White Sea Lake drained into the Barents Sea

  5. @Sea

    NSDL National Science Digital Library

    Describes the Harbor Branch Oceanographic Institution's at-sea research expeditions and presents both current and archived expeditions from 1999 to the present. Each expedition is described in a feature story with background, definitions, research technology and sampling equipment, maps, photos, daily logs, some videos and virtual tours, researcher profiles, and related links. HBOI scientists have studied maritime history, pharmaceuticals from the sea, sharks, behavior and physiology of marine life, marine sanctuaries and submersible technology.

  6. J. Great Lakes Res. 28(3):451465 Internat. Assoc. Great Lakes Res., 2002

    E-print Network

    J. Great Lakes Res. 28(3):451­465 Internat. Assoc. Great Lakes Res., 2002 Secular Changes in Great Lakes Water Level Seasonal Cycles Frank H. Quinn Great Lakes Environmental Research Laboratory National. The three primary scales of Great Lakes water level fluctuations are interannual, sea- sonal, and episodic

  7. Lake Nasser and Toshka Lakes, Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  8. The Eagle: an American brig on Lake Champlain during the War of 1812 

    E-print Network

    Crisman, Kevin James

    1984-01-01

    and launched by master shipwright Adam Brown in only 19 days during the summer of 1814. Outfitted with two masts and 20 cannon, and manned by a crew of 150 men, the brig participated in Macdonough's defeat of an invading British naval fleet at the Battle... of war. There were only two vessels at his disposal, gunboats built at Basin Harbor in 1809. They were clumsy craft in a sadly deteriorated condition, but Smith managed to get at least one of the boats refurbished and armed with a 2 9-pounder cannon...

  9. [Microbiological and isotopic geochemical investigation of Lake Kislo-Sladkoe, a meromictic water body at the Kandalaksha Bay Shore (White Sea)].

    PubMed

    Savvichev, A S; Lunina, O N; Rusanov, I I; Zakharova, E E; Veslopolova, E F; Ivanov, M V

    2014-01-01

    Microbiological, biogeochemical, and isotopic geochemical investigation of Lake Kislo-Sladkoe (Polusolenoe in early publications) at the Kandalaksha Bay shore (White Sea) was carried out in September 2010. Lake Kislo-Sladkoe was formed in the mid-1900s out of a sea gulf due to a coastal heave. At the time of investigation, the surface layer was saturated with oxygen, while near-bottom water contained sulfide (up to 32 mg/L). Total number of microorganisms was high (12.3 x 10(6) cells/mL on average). Light CO2 fixation exhibited two pronounced peaks. In the oxic zone, the highest rates of photosynthesis were detected at 1.0 and 2.0 m. The second, more pronounced peak of light CO2 fixation was associated with activity of anoxygenic phototrophic bacteria in the anoxic layer at the depth of 2.9 m (413 ?g C L(-1) day(-1)). Green-colored green sulfur bacteria (GSB) predominated in the upper anoxic layer (2.7-2.9 m), their numbers being as high as 1.12 x 10(4) cells/mL, while brown-colored GSB predominated in the lower horizons. The rates of both sulfate reduction and methanogenesis peaked in the 2.9 m horizon (1690 ?g S L(-1) day(-1) and 2.9 ?L CH4 L(-1) day(-1)). The isotopic composition of dissolved methane from the near-bottom water layer (?13C (CH4) = -87.76 per thousand) was significantly lighter than in the upper horizons (?13C (CH4) = -77.95 per thousand). The most isotopically heavy methane (?13C (CH4) = -72.61 per thousand) was retrieved from the depth of 2.9 m. The rate of methane oxidation peaked in the same horizon. As a result of these reactions, organic matter (OM) carbon of the 2.9 m horizon became lighter (-36.36 per thousand), while carbonate carbon became heavier (-7.56 per thousand). Thus, our results demonstrated that Lake Kislo-Sladkoe is a stratified meromictic lake with active microbial cycles of carbon and sulfur. Suspended matter in the water column was mostly of autochthonous origin. Anoxygenic photosynthesis coupled to utilization of reduced sulfur compounds contributed significantly to OM production. PMID:25423723

  10. [Microbiological and isotopic geochemical investigation of Lake Kislo-Sladkoe, a meromictic water body at the Kandalaksha Bay Shore (White Sea)].

    PubMed

    2014-01-01

    Microbiological, biogeochemical, and isotopic geochemical investigation of Lake Kislo-Sladkoe (Polusolenoe in early publications) at the Kandalaksha Bay shore (White Sea) was carried out in September 2010. Lake Kislo-Sladkoe was formed in the mid-1900s out of a sea gulf due to a coastal heave. At the time of investigation, the surface layer was saturated with oxygen, while near-bottom water contained sulfide (up to 32 mg/L). Total number of microorganisms was high (12.3 x 10(6) cells/mL on average). Light CO2 fixation exhibited two pronounced peaks. In the oxic zone, the highest rates of photosynthesis were detected at 1.0 and 2.0 m. The second, more pronounced peak of light CO2 fixation was associated with activity of anoxygenic phototrophic bacteria in the anoxic layer at the depth of 2.9 m (413 ?g C L(-1) day(-1)). Green-colored green sulfur bacteria (GSB) predominated in the upper anoxic layer (2.7-2.9 m), their numbers being as high as 1.12 x 10(4) cells/mL, while brown-colored GSB predominated in the lower horizons. The rates of both sulfate reduction and methanogenesis peaked in the 2.9 m horizon (1690 ?g S L(-1) day(-1) and 2.9 ?L CH4 L(-1) day(-1)). The isotopic composition of dissolved methane from the near-bottom water layer (?13C (CH4) = -87.76 per thousand) was significantly lighter than in the upper horizons (?13C (CH4) = -77.95 per thousand). The most isotopically heavy methane (?13C (CH4) = -72.61 per thousand) was retrieved from the depth of 2.9 m. The rate of methane oxidation peaked in the same horizon. As a result of these reactions, organic matter (OM) carbon of the 2.9 m horizon became lighter (-36.36 per thousand), while carbonate carbon became heavier (-7.56 per thousand). Thus, our results demonstrated that Lake Kislo-Sladkoe is a stratified meromictic lake with active microbial cycles of carbon and sulfur. Suspended matter in the water column was mostly of autochthonous origin. Anoxygenic photosynthesis coupled to utilization of reduced sulfur compounds contributed significantly to OM production. PMID:25507446

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

    USGS Publications Warehouse

    Wiche, Gregg J.; Vecchia, Aldo V.

    1996-01-01

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

  12. Rare earths and yttrium hydrostratigraphy along the Lake Kinneret–Dead Sea–Arava transform fault, Israel and adjoining territories

    Microsoft Academic Search

    P Möller; E Rosenthal; P Dulski; S Geyer; Y Guttman

    2003-01-01

    Rare earth elements and Y (REY) have been analysed in 49 groundwaters from localities in the areas of Lake Kinneret and the Jordan and Arava Valleys. These waters originate from various aquifers and the REY abundances are expected to be controlled by the aquifer rocks. The REY pattern allow one to distinguish interaction of waters with basalts, basalt-limestone interaction zones

  13. Phylogenetic status of brown trout Salmo trutta populations in five rivers from the southern Caspian Sea and two inland lake basins, Iran: a morphogenetic approach.

    PubMed

    Hashemzadeh Segherloo, I; Farahmand, H; Abdoli, A; Bernatchez, L; Primmer, C R; Swatdipong, A; Karami, M; Khalili, B

    2012-10-01

    Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes. PMID:23020557

  14. Lake trout rehabilitation in Lake Ontario

    USGS Publications Warehouse

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

    1995-01-01

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

  15. Developing Great Lakes Ice Model (GLIM) using CIOM (Coupled Ice-Ocean Model) in Lake Erie

    E-print Network

    sea ice coverage with model results for winter 2004. #12;Figure 2: Seasonal cycle of ice thickness dynamics in the Great Lakes. This is in part because sea ice dynamics and thermodynamics control the waterDeveloping Great Lakes Ice Model (GLIM) using CIOM (Coupled Ice- Ocean Model) in Lake Erie Primary

  16. Great Lakes Fieldscope

    NSDL National Science Digital Library

    This highly interactive mapping tool features rivers and streams, watershed boundaries, water depth, political boundaries, elevation and land cover of the Great Lakes region. Students, volunteers and others can upload quantitative measurements and field notes, and share this with others around the globe. This type of learning provides a rich geographic context that allows participants to gain a better understanding of how they are connected to the Great Lakes. National Geographic partnered with Michigan Sea Grant to develop Great Lakes FieldScope to encourage the exploration and investigation of Great Lakes science and education.

  17. Lake trout rehabilitation in Lake Huron

    USGS Publications Warehouse

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

    1995-01-01

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

  18. Effectiveness of Using Backpack Electrofishing Gear for Collecting Sea Lamprey ( Petromyzon marinus) Larvae in Great Lakes Tributaries

    Microsoft Academic Search

    Todd B. Steeves; Jeffrey W. Slade; Michael F. Fodale; Douglas W. Cuddy; Michael L. Jones

    2003-01-01

    The effects of water depth, larval density, stream conductance, temperature, lamprey length, and larval escapement were examined to determine the efficiency of sampling sea lamprey (Petromyzon marinus) larvae using direct current (DC) backpack electrofishing gear. A higher proportion of larvae of all sizes were collected per unit sampling effort when sample sites were shallower, contained fewer larvae, or were in

  19. Whiting in Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  20. Downstream migration of recently transformed sea lampreys before and after treatment of a Lake Michigan tributary with a lampricide

    USGS Publications Warehouse

    Hodges, John W.

    1972-01-01

    After the Pere Marquette River was treated with a lampricide in May 1964, the number of recently transformed sea lampreys (Petromyzon marinus) collected in the water-intake structure of a chemical plant near the mouth of the stream dropped 99.5%, from 13,913 (average for 1962-63 and 1963-64) to 76 (average for the next four migration seasons). Average length of the lampreys caught increased markedly after the treatment. In five of the six migration seasons, the catch of downstream migrants was higher in the fall than in the spring.

  1. Assessment of Trace Element Levels in Muscle Tissues of Fish Species Collected from a River, Stream, Lake, and Sea in Sakarya, Turkey

    PubMed Central

    Küpeli, Tülay; Altunda?, Hüseyin; ?mamo?lu, Mustafa

    2014-01-01

    Levels of some trace and essential elements, including Al, B, Ba, Cr, Cu, Fe, Mn, Ni, Sr, and Zn, were determined in 17 different fish species from Sakarya River, Çark Stream, Sapanca Lake, and Western Black Sea using ICP-OES after microwave (MW) digestion procedure. During preparation of samples for analysis, wet and MW digestion methods were also compared. Accuracy of the digestion methods was checked by the analysis of DORM-3 reference material (Fish Protein Certified Reference Material for Trace Metals). Concentrations of trace elements were found as Al: 6.5–48.5, B: 0.06–3.30, Ba: 0.09–2.92, Cr: 0.02–1.64, Cu: 0.13–2.28, Fe: 7.28–39.9, Mn: 0.08–11.4, Ni: 0.01–26.1, Sr: 0.17–13.5, and Zn: 11.5–52.9?µg?g?1. The obtained results were compared with other studies published in the literature. Trace element levels in various fish species collected from waters in Sakarya region were found to be below limit values provided by Turkish Food Codex (TFC), Food and Agriculture Organization (FAO), and World Health Organization (WHO). PMID:24790570

  2. Antibiotic producing microorganisms from River Wiwi, Lake Bosomtwe and the Gulf of Guinea at Doakor Sea Beach, Ghana

    PubMed Central

    2012-01-01

    Background Microorganisms have provided a wealth of metabolites with interesting activities such as antimicrobial, antiviral and anticancer. In this study, a total of 119 aquatic microbial isolates from 30 samples (taken from water bodies in Ghana) were screened by the agar-well diffusion method for ability to produce antibacterial-metabolites. Results Antibacterial activity was exhibited by 27 of the isolates (14 bacteria, 9 actinomycetes and 4 fungi) against at least one of the indicator microorganisms: Enterococcus faecalis (ATCC 29212), Bacillus thuringiensis (ATCC 13838), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Proteus vulgaris (NCTC 4635) and Bacillus Subtilis (NCTC 10073). A sea isolate MAI2 (identified as a strain of Pseudomonas aeruginosa) exhibited the highest antibacterial activity (lowest zone of inhibition?=?22 mm). The metabolites of MAI2 extracted with chloroform were stable to heat and gave minimum inhibitory concentrations ranging between 250 and 2000 ?g/ml. Bioautography of the extract revealed seven active components. Conclusion This study has therefore uncovered the potential of water bodies in the West African sub-region as reservoirs of potent bioactive metabolite producing microorganisms. PMID:23072432

  3. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

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

  4. Sea-Floor Images and Data from Multibeam Surveys in San Francisco Bay, Southern California, Hawaii, the Gulf of Mexico, and Lake Tahoe, California-Nevada

    USGS Publications Warehouse

    Dartnell, Peter; Gardiner, James V.

    1999-01-01

    Accurate base maps are a prerequisite for any geologic study, regardless of the objectives. Land-based studies commonly utilize aerial photographs, USGS 7.5-minute quadrangle maps, and satellite images as base maps. Until now, studies that involve the ocean floor have been at a disadvantage due to an almost complete lack of accurate marine base maps. Many base maps of the sea floor have been constructed over the past century but with a wide range in navigational and depth accuracies. Only in the past few years has marine surveying technology advanced far enough to produce navigational accuracy of 1 meter and depth resolutions of 50 centimeters. The Pacific Seafloor Mapping Project of the U.S. Geological Survey's, Western Coastal and Marine Geology Program, Menlo Park, California, U.S.A., in cooperation with the Ocean Mapping Group, University of New Brunswick, Fredericton, Canada, is using this new technology to systematically map the ocean floor and lakes. This type of marine surveying, called multibeam surveying, collects high-resolution bathymetric and backscatter data that can be used for various base maps, GIS coverages, and scientific visualization methods. This is an interactive CD-ROM that contains images, movies, and data of all the surveys the Pacific Seafloor Mapping Project has completed up to January 1999. The images and movies on this CD-ROM, such as shaded relief of the bathymetry, backscatter, oblique views, 3-D views, and QuickTime movies help the viewer to visualize the multibeam data. This CD-ROM also contains ARC/INFO export (.e00) files and full-resolution TIFF images of all the survey sites that can be downloaded and used in many GIS packages.

  5. Lateglacial of Lake Onega — Contribution to the history of the eastern Baltic basin

    Microsoft Academic Search

    Matti Saarnisto; Tuulikki Grönlund; Ilpo Ekman

    1995-01-01

    New stratigraphy data especially diatom analyses are presented from the area north of Lake Onega relevant to the discussion on possible Lateglacial connection between the Baltic Sea and White Sea. Following the deglaciation 12,000–11,000 years ago Lake Onega basin was occupied by a system of ice dammed lakes which drained to the Lake Ladoga basin. When the ice retreated from

  6. Microbial community of the deep-sea brine Lake Kryos seawater-brine interface is active below the chaotropicity limit of life as revealed by recovery of mRNA.

    PubMed

    Yakimov, Michail M; La Cono, Violetta; Spada, Gina L; Bortoluzzi, Giovanni; Messina, Enzo; Smedile, Francesco; Arcadi, Erika; Borghini, Mireno; Ferrer, Manuel; Schmitt-Kopplin, Phillippe; Hertkorn, Norbert; Cray, Jonathan A; Hallsworth, John E; Golyshin, Peter N; Giuliano, Laura

    2015-02-01

    Within the complex of deep, hypersaline anoxic lakes (DHALs) of the Mediterranean Ridge, we identified a new, unexplored DHAL and named it 'Lake Kryos' after a nearby depression. This lake is filled with magnesium chloride (MgCl2 )-rich, athalassohaline brine (salinity?>?470 practical salinity units), presumably formed by the dissolution of Messinian bischofite. Compared with the DHAL?Discovery, it contains elevated concentrations of kosmotropic sodium and sulfate ions, which are capable of reducing the net chaotropicily of MgCl2 -rich solutions. The brine of Lake Kryos may therefore be biologically permissive at MgCl2 concentrations previously considered incompatible with life. We characterized the microbiology of the seawater-Kryos brine interface and managed to recover mRNA from the 2.27-3.03?M MgCl2 layer (equivalent to 0.747-0.631 water activity), thereby expanding the established chaotropicity window-for-life. The primary bacterial taxa present there were Kebrit Deep Bacteria 1 candidate division and DHAL-specific group of organisms, distantly related to Desulfohalobium. Two euryarchaeal candidate divisions, Mediterranean Sea Brine Lakes group 1 and halophilic cluster 1, accounted for >?85% of the rRNA-containing archaeal clones derived from the 2.27-3.03?M MgCl2 layer, but were minority community-members in the overlying interface-layers. These findings shed light on the plausibility of life in highly chaotropic environments, geochemical windows for microbial extremophiles, and have implications for habitability elsewhere in the Solar System. PMID:25622758

  7. Taconic foreland basin evolution: Sedimentology and cement stratigraphy of the Black River Group limestones in the Champlain Basin

    SciTech Connect

    Bechtel, S.C.; Mehrtens, C.J. (Univ. of Vermont, Burlington, VT (United States). Geology Dept.)

    1993-03-01

    The Black River Group (Middle Ordovician, Mohawkian Series) limestones in the Champlain Basin record the transition between the shallow deposits of the underlying Chazy Group limestones and the shale-limestone couplets of the overlying Trenton Group which record rapid deepening of the foreland basin. The Black River Group was deposited in a subsiding foreland basin during the early stages of the Taconic Orogeny. Syn-depositional block faulting as a result of thrust loading has been demonstrated to affect Chazy and Trenton Group deposition. Abrupt lithofacies changes within the Black River Group record the dynamic bathymetry present in the Champlain Basin during its deposition. The Black River Group helps refine the timing of extensional block faulting during the Taconic Orogeny. The Black River Group in the Champlain Basin is a relatively thin unit, approximately 80 feet thick at Crown Point, New York. Exposures between Crown Point, NY and South Hero Island, VT record deposition of the Black River Group limestones in a protected lagoonal environment, with an evolving fringing pellet shoal barrier complex. Eight lithofacies are defined, grading from a basal sandstone and/or a sandy dolomite, to a micrite to biomicrite, to an intra-pelsparite of a shoal environment. Intraclast horizons and broken, rounded marine allochems suggest the influence of storm activity as a modifier of depositional history. Rapid deepenings into the normal marine subtidal environment, as well as micro-karst textures and fossil beach rock exposures are interpreted to represent sudden bas level changes, possibly from syndepositional block fault movement. Although dynamic bathymetry influences the stratigraphy within the Black River Group, a macro-scale deepening upwards on a formation scale is present, representing subsidence of the foreland basin.

  8. Lake Michigan Lake Breezes: Climatology, Local Forcing, and Synoptic Environment.

    NASA Astrophysics Data System (ADS)

    Laird, Neil F.; Kristovich, David A. R.; Liang, Xin-Zhong; Arritt, Raymond W.; Labas, Kenneth

    2001-03-01

    A method was developed to identify the occurrence of lake-breeze events along the eastern, western, and both shores of Lake Michigan during a 15-yr period (1982-96). Comparison with detailed observations from May through September of 1996-97 showed that the method reasonably identified Lake Michigan lake-breeze events. The method also demonstrated the important ability to distinguish non-lake-breeze events; a problem experienced by previously developed lake-breeze criteria. Analyses of the 15-yr climatological data indicated that lake breezes tended to occur more frequently along the eastern shore of Lake Michigan than along the western shore. On average, a maximum number of lake-breeze events occurred during August at each location. This maximum is most closely associated with weaker monthly average wind speeds. Even though the air-lake temperature difference T provides the local forcing for the development of the lake-breeze circulation, large temperature differences are not required. Nearly 70% of all events occurred with a daytime maximum T 12°C. The evaluation of a lake-breeze index used in past studies and many forecasting applications showed indices computed using offshore or shore-perpendicular wind speeds (U or |U|, respectively) at inland sites resolved 95% of identified events based on critical values of 2-6. When wind speed, irrespective of wind direction, was used to calculate , the success of the critical indices decreased by as much as 26%. Results also showed that the lake-breeze index has a considerable tendency to overestimate the number of events. Although the possibility was suggested by previous investigations, the critical value of may not be appreciably affected by changes in location along the shoreline. In addition, noteworthy differences in the position of synoptic-scale sea level pressure and wind fields with respect to Lake Michigan were found to occur during eastern, western, and both-shore lake-breeze events.

  9. Quaternary Science Reviews 23 (2004) 13131332 Ice-dammed lakes and rerouting of the drainage of northern

    E-print Network

    Möller, Per

    2004-01-01

    , e.g. toward the Caspian Sea, formed south of these ice sheets. Some lakes are reconstructed from, and that way to the Caspian Sea. Climate modelling shows that the lakes caused lower summer temperatures

  10. OHIO SEA GRANT AND STONE LABORATORY OHIO SEA GRANT AND STONE LABORATORY

    E-print Network

    Howat, Ian M.

    SEA GRANT AND STONE LABORATORY ·Sedimentation ·Phosphorus and nutrient loading ·Harmful algal blooms LABORATORY Blue-green Algae Bloom circa 1971, Lake Erie Photo: Forsythe and Reutter OHIO SEA GRANT AND STONE

  11. Bacterial Diversity in the Haloalkaline Lake Elmenteita, Kenya

    Microsoft Academic Search

    R. Mwirichia; S. Cousin; A. W. Muigai; H. I. Boga; E. Stackebrandt

    2011-01-01

    Lake Elmenteita is one of the alkaline saline lakes within the Kenyan Rift valley. The lake is situated on the floor of the\\u000a Kenyan Rift Valley at 1,776 m above sea level and has no direct outlet. The microbial diversity of the lake was investigated\\u000a using a culture-independent approach. Five different sampling points were selected randomly within the lake. Wet sediments

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

    USGS Publications Warehouse

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

    1995-01-01

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

  13. Sediment-current interactions at Valcour Island, Lake Champlain--A case of helical flow in the bottom boundary layer

    Microsoft Academic Search

    P. L. Manley; T. O. Manley

    1993-01-01

    Sediment furrows have been documented in diverse environments. In all cases they are morphologically similar exhibiting long, linear parallel troughs oriented with the dominant bottom current direction. The similar nature of their morphology suggests that they form as a result of a long-term interaction between the sediment surface and bottom current flow. Thus furrows are maintained in regions where bottom

  14. INVESTIGATIONS INTO THE CAUSES OF AMPHIBIAN MALFORMATIONS IN THE LAKE CHAMPLAIN BASIN OF NEW ENGLAND (AWARDED PROJECT)

    EPA Science Inventory

    The concurrent geographic extent and rate of amphibian malformations appear to have markedly increased above background levels in recent years in many states and Canadian provinces as documented by the North American Reporting Center for Amphibian Malformations (www.npwrc.usgs.go...

  15. National Sea Grant College What Does the National Sea Grant College Program Do for the Nation?

    E-print Network

    National Sea Grant College Program What Does the National Sea Grant College Program Do for the Nation? NOAA's National Sea Grant College Program enhances the practical use and conservation of coastal, marine, and Great Lakes resources to create a sustainable economy and environment. Sea Grant

  16. Sea Lamprey, an Invasive Fish

    USGS Multimedia Gallery

    Invasive sea lamprey prey on commercially important fish species such as lake trout, living off of the blood and body fluids of adult fish.  It is one of many fish species that USGS scientists study from the USGS Research Vessel Muskie. These lamprey belong to the Great Lakes Fisheries Com...

  17. Sea Lamprey, an Invasive Fish

    USGS Multimedia Gallery

    Invasive sea lamprey prey on commercially important fish species such as lake trout, living off of the blood and body fluids of adult fish. It is one of many fish species that USGS scientists study from the USGS Research Vessel Muskie. These lamprey belong to the Great Lakes Fisheries Commissio...

  18. Tapping rocks for Terror Lake hydro project

    SciTech Connect

    Sieber, O.V.

    1983-12-01

    The Terror Lake hydro project in Alaska is described. Terror Lake is a small alpine lake surrounded by barren glacier-scoured, rocky mountain tops and plateaus that do not retain moisture. The method for obtaining more water for the hydro project in Kodiak is unique. The basic program was to dam up the outlet of Terror Lake and raise the water level 170 ft. from approximately 1250 ft. above sea level to 1420 ft. Although the megawatt output of the project is small, the concept of the Terror Lake Project has an epic scale to it.

  19. Status of lake trout rehabilitation on Six Fathom Bank and Yankee Reef in Lake Huron

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; McClain, Jerry R.; Woldt, Aaron P.; Holuszko, Jeffrey D.; Bowen, Charles A., II

    2004-01-01

    Six Fathom Bank, an offshore reef in the central region of Lake Huron's main basin, was stocked annually with hatchery-reared lake trout Salvelinus namaycush during 1985-1998, and nearby Yankee Reef was stocked with hatchery-reared lake trout in 1992, 1997, and annually during 1999-2001. We conducted gill-net surveys during spring and fall to evaluate performances of each of the various strains of lake trout, as well as the performance of the entire lake trout population (all strains pooled), on these two offshore reefs during 1992-2000. Criteria to evaluate performance included the proportion of 'wild' fish within the population, spawner density, adult survival, growth, maturity, and wounding rate by sea lamprey Petromyzon marinus. Although naturally reproduced age-0 lake trout fry were caught on Six Fathom Bank and Yankee Reef, wild lake trout did not recruit to the adult population to any detectable degree. The density of spawning lake trout on Six Fathom Bank (>100 fish/305 m of gill net) during 1995-1998 appeared to be sufficiently high to initiate a self-sustaining population. However, annual mortality estimates for all lake trout strains pooled from catch curve analyses ranged from 0.48 to 0.62, well exceeding the target level of 0.40 suggested for lake trout rehabilitation. Annual mortality rate for the Seneca Lake strain (0.34) was significantly lower than that for the Superior-Marquette (0.69) and Lewis Lake (0.69) strains. This disparity in survival among strains was probably attributable to the lower sea-lamprey-induced mortality experienced by the Seneca Lake strain. The relatively high mortality experienced by adult lake trout partly contributed to the lack of successful natural recruitment to the adult population on these offshore reefs, but other factors were probably also involved. We recommend that both stocking of the Seneca Lake strain and enhanced efforts to reduce sea lamprey abundance in Lake Huron be continued.

  20. Biogeochemical phosphorus mass balance for Lake Baikal, southeastern Siberia, Russia

    USGS Publications Warehouse

    Callender, E.; Granina, L.

    1997-01-01

    Extensive data for Lake Baikal have been synthesized into a geochemical mass balance for phosphorus (P). Some of the P budget and internal cycling terms for Baikal have been compared to similar terms for oligotrophic Lake Superior, mesotrophic Lake Michigan and the Baltic Sea, and the Ocean. Lake Baikal has a large external source of fluvial P compared to the Laurentian upper Great Lakes and the Ocean. The major tributary to Lake Baikal has experienced substantial increases in organic P loading during the past 25 years. This, coupled with potential P inputs from possible phosphorite mining, may threaten Baikal's oligotrophic status in the future. Water-column remineralization of particulate organic P is substantially greater in Lake Baikal than in the Laurentian Great Lakes. This is probably due to the great water depths of Lake Baikal. There is a gradient in P burial efficiency, with very high values (80%) for Lake Baikal and Lake Superior, lower values (50%) for Lake Michigan and the Baltic Sea, and a low value (13%) for the Ocean. The accumulation rate of P in Lake Baikal sediments is somewhat greater than that in the Laurentian upper Great Lakes and the Baltic Sea, and much greater than in the Ocean. Benthic regeneration rates are surprisingly similar for large lacustrine and marine environments and supply less than 10% of the P utilized for primary production in these aquatic environments.

  1. In situ determination of the annual thermal habitat use by lake trout (Salvelinus namaycush) in Lake Huron

    USGS Publications Warehouse

    Bergstedt, Roger A.; Argyle, Ray L.; Seelye, James G.; Scribner, Kim T.; Curtis, Gary L.

    2003-01-01

    Records of the temperatures occupied by 33 lake trout (Salvelinus namaycush) at large in Lake Huron were obtained for up to 14 months per fish, at 75-minute intervals, from surgically implanted archival temperature tags. The dataset covered nearly three years, from October 1998 to June 2001, and included 160,000 observations. The objectives of the tagging were to obtain temperature data to refine bioenergetics models of sea lamprey (Petromyzon marinus) predation on lake trout, and compare the temperatures occupied by strains of lake trout stocked in Lake Huron. The seasonal, thermal-use profiles of lake trout followed the general warming and cooling pattern of Lake Huron. During periods when the zone of surface water mixing extended below the depth range occupied by lake trout, variability among individual fish and strains was low and followed surface temperature. However, during the period of summer stratification, the average temperatures occupied varied substantially among individual fish and strains. Strains originating from the upper Great Lakes (Lake Superior and Lewis Lake, WY) occupied similar temperatures. Between June and mid August, upper Great Lakes lake trout typically occupied water several degrees warmer than that occupied by lake trout of Finger Lakes, New York origin. Most of the lake trout occupied summer temperatures lower than the preferred temperatures suggested by laboratory studies. In October, all strains occupied water as warm or warmer than that occupied in summer, which may partially explain the higher lethality of sea lamprey attacks during October.

  2. Petroleum and chlorinated hydrocarbons in water from Lake Manzala and associated canals

    Microsoft Academic Search

    M. I. Badawy; R. A. Wahaab; H. F. Abou Waly

    1995-01-01

    Lake Manzala is located at the north eastern edge of Nile Delta in Egypt. It is separated from the Mediterranean sea by a sandy beach ridge. However, the lake is in connection with the sea through three opening nearby Port Said. The area of the lake is about 769 Km² and relatively shallow with an average depth of 1.3 m.

  3. Genetic strategies for lake trout rehabilitation: a synthesis

    USGS Publications Warehouse

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

    1995-01-01

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

  4. Salton: A Sea of Controversy

    NSDL National Science Digital Library

    Kristin B. Vessey

    2000-09-01

    The Salton Sea is an accidental lake that receives used irrigation water from the Colorado River. Humans have profoundly altered the area's ecosystems. The sea is important for wildlife and recreation but is now saltier than the ocean. How might it be sav

  5. 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.

  6. Sea Grant: Enhancing K-12 Education.

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.

    1998-01-01

    Sea Grant is a major contributor to marine and aquatic education in K-12 classrooms through curriculum development, teacher education, school programs at field sites, and educational research. Describes Sea Grant's efforts in these areas. Specific programs outlined include Operation Pathfinder, Ohio Sea Grant Partnerships for Great Lakes

  7. GSA Bulletin; November 2000; v. 112; no. 11; p. 16941702; 8 figures; 1 table. Transient groundwater-lake interactions in a continental rift

    E-print Network

    Lyakhovsky, Vladimir

    groundwater-lake interactions in a continental rift: Sea of Galilee, Israel Shaul Hurwitz* Eyal Stanislavsky- termediate fresh-water lake. It is postulated that during a short highstand phase of for- mer Lake Lisan basin and the instantaneous formation of the fresh-water lake (the Sea of Galilee), the previously in

  8. Aral Sea Evaporation (WMS)

    NSDL National Science Digital Library

    Joycelyn Thomson

    2005-02-15

    The Aral Sea is actually not a sea at all, but an immense fresh water lake. In the last thirty years, more than sixty percent of the lake has disappeared because much of the river flow feeding the lake was diverted to irrigate cotton fields and rice paddies. Concentrations of salts and minerals began to rise in the shrinking body of water, leading to staggering alterations in the lakes ecology and precipitous drops in the Arals fish population. Powerful winds that blow across this part of Asia routinely pick up and deposit the now exposed lake bed soil. This has contributed to a significant reduction in breathable air quality, and crop yields have been appreciably affected due to heavily salt laden particles falling on arable land. This series of Landsat images taken in 1973, 1987 and 2000 show the profound reduction in overall area at the north end of the Aral, and a commensurate increase in land area as the floor of the sea now lies exposed.

  9. Lake Temperatures

    NSDL National Science Digital Library

    NBC Learn

    2010-10-07

    Scientists studying large lakes in northern and tropical latitudes are finding that rising water temperatures are affecting the ecosystems of these lakes. "Changing Planet " is produced in partnership with the National Science Foundation.

  10. The Great Lakes--At a Crossroads Edited by Joan Chadde,

    E-print Network

    Honrath, Richard E.

    The Great Lakes--At a Crossroads Edited by Joan Chadde, Michigan Technological University/ Great Lakes Sea Grant Network I. The Great Lakes are essential to our economy and quality of life · The Great Lakes are the economic engine of the region. 40% of the Canadian and 15% of the US Gross Domestic

  11. NOAA Technical Memorandum GLERL-138 GREAT LAKES BEACH HEALTH RESEARCH NEEDS

    E-print Network

    NOAA Technical Memorandum GLERL-138 GREAT LAKES BEACH HEALTH RESEARCH NEEDS: WORKSHOP SUMMARY Great Lakes Beach Association in cooperation with NOAA, Great Lakes Environmental Research Laboratory and the Michigan Sea Grant Program U.S. Environmental Protection Agency U.S. Geological Survey Great Lakes

  12. AN INTRODUCTION TO THE PHYSICS AND CHEMISTRY OF SOME LAKES IN NORTHERN ZULULAND

    Microsoft Academic Search

    B. R. Allanson; J. D. van Wyk

    1969-01-01

    1. Lakes Sibayi and Nhlange on the coastal plain of northern Zululand are warm shallow lakes which exhibit a complex pattern of stratification during summer. In Lake Sifungwe a permanent halocline was found at 10 metres. The source of this deep salt layer is the sea, to which the lake is connected via the Kosi estuary.2. Dissolved oxygen never reaches

  13. RADAR REMOTE SENSINGOF GREAT LAKES ICE COVER G. A. Leshkevich'andS.V. Nghiem2

    E-print Network

    , unlike sea ice, has no salinity content, microwaves can propagate into lake ice unless the surface is wetRADAR REMOTE SENSINGOF GREAT LAKES ICE COVER G. A. Leshkevich'andS.V. Nghiem2 `Great Lakes: 734-741-2265, Fax: 734-741-2055 E-mail: leshkevich@glerl.noaa.aov Remote sensing of Great Lakes ice

  14. Lake Sarez, Tajikistan

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  15. The Wandering Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  16. CONNECTICUT LAKES

    EPA Science Inventory

    This is a 1:24,000-scale datalayer of named lakes in Connecticut. It is a polygon Shapefile that includes all lakes that are named on the U.S. Geologicial Survey (USGS) 7½ minute topographic quadrangle maps that cover the State of Connecticut, plus other officially named lakes i...

  17. Use of Sediment Quality Guidelines and pollution indicators for the assessment of heavy metal and PAH contamination in Greek surficial sea and lake sediments.

    PubMed

    Hahladakis, John; Smaragdaki, Eleftheria; Vasilaki, Georgia; Gidarakos, Evangelos

    2013-03-01

    Eight different surface sediment samples (K1-K8) were collected from two separate areas of Lake Koumoundourou and two samples (E1 and E2) from one area of Elefsis Bay, Athens, Greece. The level of pollution attributed to heavy metals was evaluated using several pollution indicators. Degree of Contamination, Modified Contamination Degree and Geoaccumulation Indexes were applied in order to determine and assess the anthropogenic contribution of the selected six elements (Cr, Ni, Cu, Zn, As and Pb). Moreover, the adverse effects of the sediments to aquatic organisms, from both heavy metals and polycyclic aromatic hydrocarbons (PAHs), were determined by using Sediment Quality Guidelines. The results indicated that Lake Koumoundourou is contaminated with heavy metals in a moderate degree and almost 50 % of the sediments are associated with frequent observation of adverse effects, when it comes to Ni and occasional observation of adverse effects, when it comes to Cu, Zn and Pb. As far as PAHs are concerned, around 60 % of the samples can be occasionally associated to toxic biological effects according to the effect-range classification for phenanthrene, benzo(a)anthracene, chrysene and pyrene. Finally, samples taken from the north side of the lake are more contaminated with PAHs than the ones taken from the east side probably due to the existence of the water barrier which acts as a reservoir of PAHs. PMID:22821321

  18. Lake trout (Salvelinus namaycush) populations in Lake Superior and their restoration in 1959-1993

    USGS Publications Warehouse

    Hansen, Michael J.; Peck, James W.; Schorfhaar, Richard G.; Selgeby, James H.; Schreiner, Donald R.; Schram, Stephen T.; Swanson, Bruce L.; MacCallum, Wayne R.; Burnham-Curtis, Mary K.; Curtis, Gary L.; Heinrich, John W.; Young, Robert J.

    1995-01-01

    Naturally-reproducing populations of lake trout (Salvelinus namaycush) have been re-established in most of Lake Superior, but have not been restored to 1929-1943 average abundance. Progress toward lake trout restoration in Lake Superior is described, management actions are reviewed, and the effectiveness of those actions is evaluated; especially stocking lake trout as a tool for building spawning stocks, and subsequently, populations of wild recruits. Widespread destruction of lake trout stocks in the 1950s due to an intense fishery and sea lamprey (Petromyzon marinus) predation resulted in lower overall phenotypic diversity than was previously present. Stocking of yearling lake trout, begun in the 1950s, produced high densities of spawners that reproduced wherever inshore spawning habitat was widespread. Sea lampreys were greatly reduced beginning in 1961, using selective chemical toxicants and barrier dams, but continue to exert substantial mortality. Fishery regulation was least effective in Wisconsin, where excessive gillnet effort caused high by catch of lake trout until 1991, and in eastern Michigan, where lake trout restoration was deferred in favor of a tribal fishery for lake whitefish (Coregonus clupeaformis) in 1985. Restoration of stocks was quicker in offshore areas where remnant wild lake trout survived and fishing intensity was low, and was slower in inshore areas where stocked lake trout reproduced successfully and fishing intensity was high. Inshore stocks of wild lake trout are currently about 61% of historic abundance in Michigan and 53% in Wisconsin. Direct comparison of modern and historic abundances of inshore lake trout stocks in Minnesota and Ontario is impossible due to lack of historic stock assessment data. Stocks in Minnesota are less abundant at present than in Michigan or Wisconsin, and stocks in Ontario are similar to those in Michigan. Further progress in stock recovery can only be achieved if sea lampreys are depressed and if fisheries are constrained further than at present.

  19. Lake surface water temperature retrieval using advanced very high resolution radiometer and

    E-print Network

    Wunderle, Stefan

    Lake surface water temperature retrieval using advanced very high resolution radiometer high resolution radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer sea surface temperature algorithms to derive operational lake surface water temperature (LSWT). A validation study

  20. Hunting the Higgs Lake Geneva

    E-print Network

    Lawrence, Rick L.

    Hunting the Higgs Lake Geneva CMS ATLAS LHCb ALICE C. Riedel MSU Physics October 26, 2012 #12;What is a Higgs boson? #12;Examples of Symmetries Continuous: Translational, Temporal, Rotational. Conservation q = 0 q = -e mass players #12;The Higgs Mechanism In quantum theory, the vacuum contains a sea

  1. Hydrologic considerations in dewatering and refilling Lake Carlton : Orange and Lake Counties, Florida

    USGS Publications Warehouse

    Anderson, Warren; Hughes, G.H.

    1977-01-01

    Lake Carlton straddles the line between Lake and Orange Counties in central Florida. The 382-acre lake is highly eutrophic and subject to virtually perpetual algal blooms. The Florida Game and Fresh Water Fish Commission has proposed to restore the lake to a less eutrophic state by dewatering the lake long enough to allow the muck on its bottom to dry and compact. Lake Carlton would be permanently sealed off from Lake Carlton. On the assumption that the seasonal rainfall would be normal, and that the dewatering phase would begin on March 1, the predicted time required to dewater the lake at a pumping rate of 50,000 gpm (gallons per minute) is 21 days. The average rate of pumping required to maintain the lake in a dewatered condition is computed to be 2,400 gpm. If pumping is ended May 31, the predicted altitude to which the lake would recover by October 31 as a result of net natural input is 56.2 feet above sea level. Raising the lake level to 63 feet above sea level by October 31 would require that the net natural input be supplemented at an average rate of about 4,860 gpm between May 31 and October 31. (Woodard-USGS)

  2. EVALUATION OF THE ROLE OF SEA SALT IMPUTS IN THE LONG-TERM ACIDIFICATION OF COASTAL NEW ENGLAND LAKES (JOURNAL VERSION)

    EPA Science Inventory

    Input of neutral salt (NaCl) from sea spray, followed by Na(sup +)-H(sup +) exchange within the soil exchange complex, has been proposed as an important factor in surface water acidification of coastal areas. This hypothesis was tested on a regional basis by comparing the Na:Cl r...

  3. Lake trout population dynamics in the Northern Refuge of Lake Michigan: implications for future rehabilitation

    USGS Publications Warehouse

    Madenjiana, Charles P.; DeSorcie, Timothy J.

    2010-01-01

    The Northern Refuge was established in 1985 as part of the lake trout Salvelinus namaycush rehabilitation effort for Lake Michigan. To evaluate progress toward lake trout rehabilitation in the Northern Refuge, we conducted annual (1991–2008) gill-net surveys in the fall to assess the adult population and beam trawl surveys in the spring to assess naturally reproduced age-0 lake trout. Our criteria for evaluating progress included the density of “wild” age-0 fish within the Northern Refuge, the proportion of wild fish within the adult population, density of spawners, adult survival, growth, and wounding rate by sea lampreys Petromyzon marinus. No wild age-0 lake trout were caught in the Northern Refuge during 1991–2008. Overall, wild lake trout did not recruit to the adult population to any detectable degree. The mean density of spawning lake trout decreased from 45 fish·305 m of gill net?1·d?1 during 1991–1999 to only 4 fish·305 m?1·d?1 during 2000–2008. Although the sea lamprey wounding rate more than doubled between these two time periods, catch curve analysis revealed that mortality of adult lake trout actually decreased between the two periods. Therefore, the 90% decrease in abundance of spawning lake trout between the two periods could not be attributed to increased sea lamprey predation but instead was probably due in part to the reduced lake trout stocking rate during 1995–2005. The paucity of natural reproduction in the Northern Refuge during 1991–2008 most likely resulted from alewife Alosa pseudoharengus interference with lake trout reproduction and from the relatively low lake trout spawner density during 2000–2008. Our results suggest that the annual stocking rate of lake trout yearlings should be increased to at least 250,000 fish/reef to achieve greater densities of spawners.

  4. Modeling Lake Erie ice dynamics: Process studies , Haoguo Hu2

    E-print Network

    modeling in Lake Erie (Wake and Rumer, 1979, 1983) based on Hibler's (1979) dynamic-thermodynamic sea-ice efforts in coupled ice-ocean modeling in many subpolar seas and bays, such as in Hudson Bay (Wang et al with a viscous-plastic sea ice constitutive law (Hibler, 1979) and a multi-category ice thickness distribution

  5. Lake trout population dynamics at Drummond Island Refuge in Lake Huron: Implications for future rehabilitation

    USGS Publications Warehouse

    Madenjian, C.P.; Ebener, M.P.; Desorcie, T.J.

    2008-01-01

    The Drummond Island Refuge (DIR) was established in 1985 as part of the rehabilitation effort for lake trout Salvelinus namaycush in Lake Huron. Since then, several strains of hatchery-reared lake trout have been stocked annually at the DIR. An intensive lampricide treatment of the St. Marys River during 1998-2001 was expected to lower the abundance of sea lamprey Petromyzon marinus within the DIR by 2000. We conducted annual gill-net surveys during spring and fall to evaluate the performance of each of the strains of lake trout as well as that of the entire lake trout population (all strains pooled) in the DIR during 1991-2005. The criteria to evaluate performance included the proportion of "wild" fish within the population, spawner density, adult survival, growth, maturity, and wounding rate by sea lampreys. Wild lake trout did not recruit to the adult population to any detectable degree. During 1991-2005, the average density of spawning lake trout appeared to be marginally sufficient to initiate a self-sustaining population. Survival of the Seneca Lake (SEN) strain of lake trout was significantly higher than that of the Superior-Marquette (SUP) strain, in part because of the higher sea-lamprey-induced mortality suffered by the SUP strain. However, other factors were also involved. Apparently SUP fish were more vulnerable to fishing conducted in waters near the refuge boundaries than SEN fish. The St. Marys River treatment appeared to be effective in reducing the sea lamprey wounding rate on SEN fish. We recommend that the stocking of SEN lake trout in the DIR, control of sea lampreys in the St. Marys River, and reduction of commercial fishery effort in waters near the DIR be maintained. ?? Copyright by the American Fisheries Society 2008.

  6. Water, salt, and energy balances of the Dead Sea

    Microsoft Academic Search

    N. G. Lensky; Y. Dvorkin; V. Lyakhovsky; I. Gertman; I. Gavrieli

    2005-01-01

    The Dead Sea is a hypersaline terminal lake experiencing a water level drop of about 1 m\\/yr over the last decade. The existing estimations for the water balance of the lake are widely variable, reflecting the unknown subsurface water inflow, the rate of evaporation, and the rate of salt accumulation at the lake bottom. To estimate these we calculate the

  7. A comparison of organic contaminants in two high Arctic lake ecosystems, Bjørnøya (Bear Island), Norway

    Microsoft Academic Search

    Anita Evenset; Guttorm N Christensen; Trond Skotvold; Eirik Fjeld; Martin Schlabach; Elleke Wartena; Dennis Gregor

    2004-01-01

    Lake Ellasjøen and Lake Øyangen are two high Arctic lake ecosystem located on the island Bjørnøya (74°30? N, 19°00? E) in the Barents Sea. High levels of persistent organic pollutants (POPs), especially PCB and p,p?-DDE, were found in sediment and biota from Lake Ellasjøen while levels were several times lower in Lake Øyangen. Stable isotope signatures (?15N) in comparable organisms

  8. Beaufort Sea! Chukchi Sea!

    E-print Network

    Pickart, Robert S.

    Beaufort Sea! Chukchi Sea! Herald Shoal Hanna Shoal Barrow Canyon Herald Canyon Bering Strait of the Alaska Coastal Current (a) Bering Strait! (b) Central Shelf! (c) BCH! (d) BCC/DBO! (e) BCM! BCC avg the Arctic Ocean through Bering Strait is transported across the shallow and expansive Chukchi Sea through

  9. LAKE FORK

    EPA Science Inventory

    The Lake Fork of the Arkansas River Watershed has been adversely affected through mining, water diversion and storage projects, grazing, logging, and other human influences over the past 120 years. It is the goals of the LFWWG to improve the health of Lake fork by addressing th...

  10. Lake Powell

    Atmospheric Science Data Center

    2014-05-15

    ... with the construction of the Glen Canyon Dam in 1963, on the Colorado River in Page, Arizona and is the second largest man-made lake in the ... side canyons and holds approximately 8.5 trillion gallons of water. The lake's coast line of approximately 1960 miles is greater than the ...

  11. Lake Restoration: Medical Lake, Washington

    Microsoft Academic Search

    Raymond A. Soltero; Donald G. Nichols; Anthony F. Gasperino; Michael A. Beckwith

    1981-01-01

    For several decades the thick algal scums and offensive odors of Medical Lake have limited its use. High phosphorus levels, resulting from internal cycling of the nutrient, were responsible for the excessive algal growth. Disruption of the cycle was achieved by whole-lake applications of aluminum sulfate. The treatment significantly reduced phosphorus levels, eliminated nuisance blooms and enhanced water clarity.

  12. Development of an advanced technique for mapping and monitoring sea and lake ice for the future GOES-R Advanced Baseline Imager (ABI)

    NASA Astrophysics Data System (ADS)

    Nazari, Rouzbeh

    Information on ice cover extent, distribution, concentration, ice surface temperature and other physical parameters of the ice pack is needed in numerical weather prediction, ship navigation, water management, and regional/global climate change impact assessment. Ice cover is also a sensitive indicator of climate variations. Ability of satellites to provide global observations at high temporal frequency has made them the primary tool for the ice cover monitoring. The main objective of this research is to explore the potentials of mapping ice cover with the future GOES-R ABI and to develop an automated ice-mapping algorithm which would make maximum use of ABI's improved observing capabilities and its frequent observation will provide an extreme enhanced temporal variability of scene response to improve image classification. Data collected by SEVIRI instrument onboard of the Meteosat Second Generation (MSG) satellite have been used as a prototype. The Northern region of the Caspian Sea has been selected for algorithm development and calibration. The approach used in the algorithm development includes daily cloud-clear image compositing as well as pixel-by-pixel image classification using spectral criteria. Available spectral channels (reflectance and temperature) have been tested and used in a statistical-based approach to accurately discriminate between water, cloud and ice pixels. To assess the accuracy of ice mapping algorithm and maps, the produced ice maps over Caspian Sea derived with the automated algorithm were compared with interactive snow/ice charts produced with NOAA Interactive Multi-sensor Snow and Ice Mapping System (IMS). The results are promising and an additional screening is undergoing further research in order to reduce some remaining confusions related to water properties and presence of fractional ice.

  13. The Disappearing Aral Sea

    NSDL National Science Digital Library

    In just 30 years, the Aral Sea has lost more than 60 percent of its water. Barring change, it may disappear entirely by 2020. In this visualization, satellite images dating from 1973 to 2000 show how water diverted from this inland lake for agriculture has caused it to shrink considerably over a short period of time. The feature can be run as an animation or as a series of slides. A background essay and discussion questions are included.

  14. Lake Nipigon

    NSDL National Science Digital Library

    2001-01-01

    These recent postings from the Canada Centre for Remote Sensing's (CCRS) "Images of Canada" series provide an interesting introduction to remote sensing techniques and the history of landforms, both natural and human-made. The Landsat image of Ontario's Lake Nipigon, a name meaning "deep, clear lake," is viewable in two sizes and is accompanied by text and other remote images on the structural geology, rock types, recent forest fires, and forestry research around the lake. The CCRS was last mentioned in the May 24, 2000 Scout Report for Science and engineering.

  15. The discovery of stromatolites developing at 3570 m above sea level in a high-altitude volcanic lake Socompa, Argentinean Andes.

    PubMed

    Farías, María E; Rascovan, Nicolás; Toneatti, Diego M; Albarracín, Virginia H; Flores, María R; Poiré, Daniel G; Collavino, Mónica M; Aguilar, O Mario; Vazquez, Martin P; Polerecky, Lubos

    2013-01-01

    We describe stromatolites forming at an altitude of 3570 m at the shore of a volcanic lake Socompa, Argentinean Andes. The water at the site of stromatolites formation is alkaline, hypersaline, rich in inorganic nutrients, very rich in arsenic, and warm (20-24°C) due to a hydrothermal input. The stromatolites do not lithify, but form broad, rounded and low-domed bioherms dominated by diatom frustules and aragonite micro-crystals agglutinated by extracellular substances. In comparison to other modern stromatolites, they harbour an atypical microbial community characterized by highly abundant representatives of Deinococcus-Thermus, Rhodobacteraceae, Desulfobacterales and Spirochaetes. Additionally, a high proportion of the sequences that could not be classified at phylum level showed less than 80% identity to the best hit in the NCBI database, suggesting the presence of novel distant lineages. The primary production in the stromatolites is generally high and likely dominated by Microcoleus sp. Through negative phototaxis, the location of these cyanobacteria in the stromatolites is controlled by UV light, which greatly influences their photosynthetic activity. Diatoms, dominated by Amphora sp., are abundant in the anoxic, sulfidic and essentially dark parts of the stromatolites. Although their origin in the stromatolites is unclear, they are possibly an important source of anaerobically degraded organic matter that induces in situ aragonite precipitation. To the best of our knowledge, this is so far the highest altitude with documented actively forming stromatolites. Their generally rich, diverse and to a large extent novel microbial community likely harbours valuable genetic and proteomic reserves, and thus deserves active protection. Furthermore, since the stromatolites flourish in an environment characterized by a multitude of extremes, including high exposure to UV radiation, they can be an excellent model system for studying microbial adaptations under conditions that, at least in part, resemble those during the early phase of life evolution on Earth. PMID:23308236

  16. Pyramid Lake

    USGS Multimedia Gallery

    Pyramid Lake, Nevada, not only holds deep cultural connections for the Paiute Tribe and tribal member Dan Mosely (pictured), but also supports a tribal economy centered on fishing and recreational activities. ...

  17. Aquatic bird populations as possible indicators of seasonal nutrient flow at Ichkeul Lake, Tunisia

    Microsoft Academic Search

    Alain Tamisier; Charles Boudouresque

    1994-01-01

    Lake Ichkeul is fed in autumn and winter by 7 main freshwater oueds (rivers) which create an overflow towards the mediterranean sea. Conversely, seawater enters the lake after the end of the rainy season. Thus, strong inverse variations occur twice a year both in water depth and salinity level, with a major hydraulic flow to the sea between October and

  18. Introduction to the Great Lakes

    NSDL National Science Digital Library

    Reference information on this site discusses one of the youngest natural features on the North American continent, the Great Lakes. Covering more than 94,000 square miles and draining more than twice as much land, these freshwater seas hold an estimated 6 quadrillion gallons of water, about one-fifth of the world's fresh surface water supply and nine-tenths of the U.S. supply. Students will discover that the Great Lakes watershed includes part or all of eight U.S. states (Minnesota, Wisconsin, Illinois, Indiana, Michigan, Ohio, Pennsylvania and New York) and the Canadian province of Ontario. The site offers a page of information on each lake, including descriptions and statistics.

  19. Variability of transparent organic particles in Arctic floodplain lakes

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-02-01

    The Mackenzie River in the North American Arctic courses into the Beaufort Sea, the outlet of a watershed that drains a vast swath of the western Canadian landscape. At the river's mouth the Mackenzie Delta is a broad floodplain peppered with roughly 45,000 lakes carved into the permafrost. Depending on their connectivity to the river, these floodplain lakes have different mixtures of organic compounds, and such differences affect carbon cycling and sediment processes in the lakes.

  20. Hydrology of Alpine Lake Waiau, Mauna Kea, Hawaii

    Microsoft Academic Search

    B. L. Ehlmann; R. E. Arvidson; B. L. Joliff; R. E. Criss; F. P. Seelos

    2002-01-01

    Alpine Lake Waiau, located at 3965 m above sea level on the summit of Mauna Kea, Hawaii, is part of a unique glacial-volcanic landscape that has deep historical and cultural significance for Native Hawaiians. Using topographic information, daily meteorological data from August 1999 to February 2002, and calibration with lake level and isotope measurements taken in August 1999 - 2001

  1. Biology of penaeid prawns in the Suez Canal lakes

    Microsoft Academic Search

    A. A.-F. A. Gab-Alla; R. G. Hartnoll; A.-F. Ghobashy; S. Z. Mohammed

    1990-01-01

    A study was made from January 1988 to March 1989 of the penaid prawns in the Great Bitter Lake and Lake Timsah located in the central part of the Suez Canal. Two species of Red Sea origin were investigated,Metapenaeus stebbingi andTrachypenaeus curvirostris; the former is by far the commoner. Both species displayed seasonal breeding over the period April to October,

  2. Australian salt lakes: their history, chemistry, and biota — a review

    Microsoft Academic Search

    Patrick De Deckker

    1983-01-01

    A vast number of large lakes (» 100 km2) are typically very old features of the Australian landscape; they occupy areas which have changed little tectonically (e.g., they occupy ancient drainage systems in Western Australia or lie in deep depressions such as the Great Artesian Basin: Lake Eyre) and have not been transgressed by the sea since at least the

  3. ENVIRONMENTAL PROBLEMS IN TWO EGYPTIAN SHALLOW LAKES SUBJECTED TO DIFFERENT LEVELS OF POLLUTION

    Microsoft Academic Search

    Massoud A. H. Saad; A. M. Safty

    2004-01-01

    The two study areas are Lake Mariut and the Nozha Hydrodrome. The water of Lake Mariut is pumped to the Mediterranean Sea. It is the heavily polluted basin in Egypt receiving huge amounts of contaminated drainage waters and untreated domestic and industrial wastes. The Hydrodrome was separated in 1939 from Lake Mariut and became polluted in recent years from the

  4. Nannoplankton of Marine Origin from Great Bear Lake in the Northwest Territories of Canada

    Microsoft Academic Search

    A. S. Bursa; L. Johnson

    1967-01-01

    GREAT Bear Lake is situated on the Arctic Circle at a point where the Pre-Cambrian Shield emerges from the adjoining Cretaceous formations. The present lake surface is 143 m above sea level, and because the maximum depth is 542 m there is a cryptodepression of 309 m. The shape of the lake could be described as amoeboid with five arms

  5. Low-Head Barrier Dams Restrict the Movements of Fishes in Two Lake Ontario Streams

    Microsoft Academic Search

    L. M. Porto; R. L. McLaughlin; D. L. G. Noakes

    1999-01-01

    The Great Lakes Fishery Commission (GLFC) is considering greater use of low-head barrier dams on stream tributaries of the Laurentian Great Lakes to control populations of sea lampreys Petromyzon marinus. The impact of these barriers on nontarget fishes is not known. A mark–recapture study on four Lake Ontario streams examined movements of fishes in streams with (barrier) and without (reference)

  6. Principles of lake sedimentology

    SciTech Connect

    Janasson, L.

    1983-01-01

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

  7. Great Lakes Climate and Water Movement. Earth Systems - Education Activities for Great Lakes Schools (ES-EAGLS).

    ERIC Educational Resources Information Center

    Miller, Heidi, Ed.; Sheaffer, Amy L., Ed.

    This activity book is part of a series designed to take a concept or idea from the existing school curriculum and develop it in the context of the Great Lakes using teaching approaches and materials appropriate for students in middle and high school. The theme of this book is Great Lakes climate and water movement. Students learn about land-sea

  8. Sea Education Association (SEA)

    NSDL National Science Digital Library

    The Sea Education Association (SEA) in Woods Hole, MA provides undergraduates with an opportunity to participate in an academic study-abroad program called the SEA Semester. The program combines intensive research in the areas of oceanography, maritime studies, and nautical science with hands-on experience aboard a traditional sailing ship. Piloting, celestial navigation, and practical seamanship are learned together with oceanographic sampling techniques and marine laboratory procedures. Critical thinking, problem-solving, team-building and leadership skills are emphasized throughout the program. SEA Semester is appropriate for students in marine biology, geology and physical science, environmental studies, American studies, and most other areas within the liberal arts and sciences. Academic credit for SEA Semester is obtained through Boston University.

  9. Development of an Advanced Technique for Mapping and Monitoring Sea and Lake Ice in Preparation for GOES-R Advanced Baseline Imager (ABI)

    NASA Astrophysics Data System (ADS)

    Nazari, R.; Temimi, M.; Khanbilvardi, R.; Romanov, P.

    2008-05-01

    In recent years, the uniqueness of the Earth's ice covered regions and their importance to the world is being increasingly recognized. They are considered vital and valuable for a variety of economic, environmental, and social reasons. Ice information can also improve weather and climate predictions. Observations show that Arctic ice is decreasing in both thickness and extent which will lead to the change in absorption of solar radiation and temperature of the earth. The increasing activity in ice-affected waters has led to a growing requirement for ice information and better mapping systems with improvements in both time and spatial resolution. A variety of Earth Observation sensors are used to map ice covered areas. Visible-Infrared sensors at moderate-resolution from polar orbiting satellites (NOAA-AVHRR, MODIS Aqua/ Terra) have been used extensively because of their easy accessibility. However, clouds, fog and low time resolutions limit the use of this type of sensor to fully meet operational ice mapping requirements, particularly in cloud- and fog ice zones. The primary objective of this research is to explore the potentials of mapping ice with the geostationary satellites which can provide a reasonably good time resolution and satisfactory spatial resolutions. The aim of this ongoing project is to develop an automated ice-mapping algorithm, which would make maximum use of GOES-R ABI's improved observing capabilities and to be the pioneer of creating daily ice maps from a geostationary satellite. Data collected by SEVIRI instrument onboard of Meteosat Second Generation (MSG) satellite have been used as a prototype. The Northern region of the Caspian Sea has been selected for algorithm development and calibration. The approach used in the algorithm development includes daily cloud-clear image compositing as well as pixel-by-pixel image classification using spectral criteria. All available spectral channels (reflectance and temperature) have been tested and used in order to accurately classify Cloud, water and ice. The preliminary steps of the research will focus on correcting the BRDF effect of ice and developing a new ICE BRDF model to be used for such regions. In the next step the BRDF model will be used as a base for future classification and retrieval of cloud, water and ice pixels and addendum of other spectral bands.

  10. Probable Maximum Flood at Lake Chippewa near Winter, Wisconsin

    USGS Publications Warehouse

    Krug, William R.

    1976-01-01

    The probable maximum flood was computed for Lake Chippewa, Wisconsin, and routed through the lake to determine maximum lake stage. The peak discharge of the probable maximum flood at Lake Chippewa was computed to be about 75,000 cubic feet per second, primarily caused by rainfall on the lake. A secondary peak of about 41,000 cubic feet per second was due to streamflow entering Lake Chippewa. The 14-day volume of this flood was 450 ,000 acre-feet. Using an assumed operating procedure for Winter Dam, the maximum lake stage for the probable maximum flood was computed to be about 1,318 feet above mean sea level--about 3 feet below the dam crest and 6 feet above the proposed normal summer operating level. The probability of this flood occurring in any year is less than 1 in 10,000. (Woodard-USGS)

  11. Lake studies from satellite radar altimetry

    Microsoft Academic Search

    Jean-François Crétaux; Charon Birkett

    2006-01-01

    For more than 10 years, satellite radar altimetry has been a successful technique for monitoring the variation in elevation of continental surface water, such as inland seas, lakes, rivers, and more recently wetland zones. The surface water level is measured within a terrestrial reference frame with a repeatability varying from 10 to 35 days depending on the orbit cycle of

  12. Epidemiology of great lakes bald eagles

    Microsoft Academic Search

    Theo Colborn

    1991-01-01

    Historical data are provided to support the hypothesis that organochlorine chemicals introduced into the Great Lakes ecosystem following World War II are the cause of reproductive loss among bald eagles (Haliaeetus leucocephalus) in the basin. This is supported with data on concurrent population fluxes of extrabasin North American bald eagle populations and the European white?tailed sea eagle (Haliaeetus albicillus.) where

  13. Ocean and Great Lakes Awareness Survey.

    ERIC Educational Resources Information Center

    Fortner, Rosanne W.

    This survey was developed by the Ohio Sea Grant Education Program in 1979. It is been used every four years as a repeated measure of Ohio students' knowledge and attitudes about the oceans and Great Lakes, charting changes in those attributes as means of determining how well Ohio citizens are being prepared for decisionmaking about those bodies of…

  14. Land-lake breezes at low latitudes: The case of Tonle Sap Lake in Cambodia

    NASA Astrophysics Data System (ADS)

    Tsujimoto, Kumiko; Koike, Toshio

    2013-07-01

    Tonle Sap Lake is the largest freshwater lake in Southeast Asia. During the postmonsoon season, a small linear cloud system has been observed over this lake in early morning, while the sky above the surrounding land is clear. Although this cloud system is apparently generated by land breezes, previous studies on land-lake (sea) circulation have suggested that environmental factors at low latitudes inhibit development of nocturnal land breezes. In this study, we investigate the mechanism of these early morning clouds through numerical simulation. The simulations show a linear updraft system over the lake, forming along the southwest lakeshore around 22:00 and moving northeast to the middle of the lake. The heavier air mass from the land meets the extraordinarily warm and humid air mass over the lake, triggering updrafts under the conditionally convective instability. The characteristic high surface water temperature was favorable for generation of the land breeze and updraft systems. That high surface water temperature of the lake is produced by the tropical climate along with efficient energy absorption because of the shallowness of the water body. This unique feature can generate a clear nocturnal land breeze circulation accompanying a migrating updraft system over the lake despite its low latitude.

  15. Paleoceanography and glacial runoff along the St. Lawrence valley system

    SciTech Connect

    Rodrigues, C.G. (Univ. of Windsor, Windsor, Ontario (Canada). Dept. of Geology); Vilks, G. (Bedford Inst. of Oceanography, Dartmouth, NS (United States))

    1992-01-01

    Radiocarbon-dated foraminiferal zones in cores from the Gulf of St. Lawrence show that cold saline bottom-water was present in the Goldthwait Sea between 13.6 and 12.9 ka BP and was followed by a salinity minimum from ca. 12.1 to 8.6 ka BP, and then increasing salinity and temperature resulting in the modern, deep, watermass layer by 8 ka BP. During the salinity minimum, glacial Lake St. Lawrence drained east into the Goldthwait Sea before the beginning of the Champlain Sea (11.6--11.4 ka BP). Meltwater flowed through the Champlain and Goldthwait seas between 11 and 10 ka BP when Lake Agassiz water was diverted to the North Atlantic Ocean through Ottawa and St. Lawrence valleys and Gulf of St. Lawrence; this coincides with the decrease in salinity of the Champlain Sea between 10.7 and 10.4 ka BP. A later discharge of meltwater to the North Atlantic Ocean (9.5--8 ka BP) occurred during the final stage of the salinity minimum in the Goldthwait Sea and postdates or coincides with the end of the Champlain Sea. The discharge of meltwater to the North Atlantic Ocean may have cause the freshening of the Champlain Sea. However, it does not appear to have affected the deep water in the Goldthwait Sea and was probably part of the surface outflow to the North Atlantic Ocean through the Gulf of St. Lawrence. The variations in salinity of the deep water of the Goldthwait Sea are related to changes in the composition of the water entering the sea from the North Atlantic Ocean.

  16. Density-independent survival of wild lake trout in the Apostle Islands area of Lake Superior

    USGS Publications Warehouse

    Bronte, Charles R.; Schram, Stephen T.; Selgeby, James H.; Swanson, Bruce L.

    1995-01-01

    The lake trout (Salvelinus namaycush) stock at Gull Island Shoal in western Lake Superior was one of only a few stocks of lean lake trout in the Great Lakes that survived overfishing and predation by the sea lamprey (Petromyzon marinus). Since the mid 1960s, the abundance of wild recruits measured at age 0 and the number of age-7 to -11 wild fish recruited to the fishable stock have increased. We used the Varley-Gradwell method to test for density-dependent survival between these life stages. Survival from age-0 to ages 7-11 was not affected by increasing density, which suggests that further increases in recruitment and stock size are still possible. We suggest that testing for the existence of density-dependent survival can be used to indicate when lake trout populations are rehabilitated.

  17. Lake Victoria

    NSDL National Science Digital Library

    This online article, from "The Biodiversity Crisis: Losing What Counts", provides insight into how human behavior has put one of the world's largest ecosystems close to death. It covers the astonishingly diverse cichlid species that live only in Lake Victoria and changes to the ecosystem brought about by the introduction of a non-native species.

  18. Great Lakes Information Network

    NSDL National Science Digital Library

    The Great Lakes Information Network (GLIN) is a partnership that has compiled information relating to the binational Great Lakes-St. Lawrence region of North America. Sections of the site include an overview of the Great Lakes, the environment of the Great Lakes, the economy of the Great Lakes, education, maps and Geographic Information Systems (GIS), and tourism.

  19. Changing Planet: Warming Lakes

    NSDL National Science Digital Library

    Windows to the Universe/NBC Learn

    The video addresses impact of warming temperatures on major lakes of the world with specific focus on Lake Superior and Lake Tanganyika. It discusses the science of water stratification and its impact on lake ecosystems and on human populations whose livelihoods depend on the lakes.

  20. Astrobiology of Antarctic ice Covered Lakes

    NASA Astrophysics Data System (ADS)

    Doran, P. T.; Fritsen, C. H.

    2005-12-01

    Antarctica contains a number of permanently ice-covered lakes which have often been used as analogs of purported lakes on Mars in the past. Antarctic subglacial lakes, such as Lake Vostok, have also been viewed as excellent analogs for an ice covered ocean on the Jovian moon Europa, and to a lesser extend on Mars. Lakes in the McMurdo Dry Valleys of East Antarctica have ice covers that range from 3 to 20 meters thick. Water salinities range from fresh to hypersaline. The thinner ice-covered lakes have a well-documented ecology that relies on the limited available nutrients and the small amount of light energy that penetrates the ice covers. The thickest ice-covered lake (Lake Vida in Victoria Valley) has a brine beneath 20 m of ice that is 7 times sea water and maintains a temperature below -10 degrees Celsius. This lake is vastly different from the thinner ice-covered lakes in that there is no communication with the atmosphere. The permanent ice cover is so thick, that summer melt waters can not access the sub-ice brine and so the ice grows from the top up, as well as from the bottom down. Brine trapped beneath the ice is believed to be ancient, stranded thousands of years ago when the ice grew thick enough to isolate it from the surface. We view Lake Vida as an excellent analog for the last aquatic ecosystem to have existed on Mars under a planetary cooling. If, as evidence is now increasingly supporting, standing bodies of water existed on Mars in the past, their fate under a cooling would be to go through a stage of permanent ice cover establishment, followed by a thickening of that ice cover until the final stage just prior to a cold extinction would be a Lake Vida-like lake. If dust storms or mass movements covered these ancient lakes, remnants may well be in existence in the subsurface today. A NASA Astrobiology Science and Technology for Exploring Planets (ASTEP) project will drill the Lake Vida ice cover and access the brine and sediments beneath in November 2005. This presentation will include an update from the field.

  1. Is the Relationship between Great Lakes Ice Cover and Climate Patterns Statistically Significant?

    E-print Network

    and climate GCM products along with historical sea ice observations including recent satellite measurements be used to conduct linear regression to sea ice cover. The lake ice composite analyses will be conducted. Furthermore, a linear regression of the AO/NAO and ENSO indices will be applied to sea ice concentration

  2. The High-Lakes Project

    NASA Astrophysics Data System (ADS)

    Cabrol, Nathalie A.; Grin, Edmond A.; Chong, Guillermo; Minkley, Edwin; Hock, Andrew N.; Yu, Youngseob; Bebout, Leslie; Fleming, Erich; Häder, Donat P.; Demergasso, Cecilia; Gibson, John; Escudero, Lorena; Dorador, Cristina; Lim, Darlene; Woosley, Clayton; Morris, Robert L.; Tambley, Cristian; Gaete, Victor; Galvez, Matthieu E.; Smith, Eric; Uskin-Peate, Ingrid; Salazar, Carlos; Dawidowicz, G.; Majerowicz, J.

    2009-06-01

    The High Lakes Project is a multidisciplinary astrobiological investigation studying high-altitude lakes between 4200 m and 6000 m elevation in the Central Andes of Bolivia and Chile. Its primary objective is to understand the impact of increased environmental stress on the modification of lake habitability potential during rapid climate change as an analogy to early Mars. Their unique geophysical environment and mostly uncharted ecosystems have added new objectives to the project, including the assessment of the impact of low-ozone/high solar irradiance in nonpolar aquatic environments, the documentation of poorly known ecosystems, and the quantification of the impact of climate change on lake environment and ecosystem. Data from 2003 to 2007 show that UV flux is 165% that of sea level with maximum averaged UVB reaching 4 W/m2. Short UV wavelengths (260-270 nm) were recorded and peaked at 14.6 mW/m2. High solar irradiance occurs in an atmosphere permanently depleted in ozone falling below ozone hole definition for 33-36 days and between 30 and 35% depletion the rest of the year. The impact of strong UVB and UV erythemally weighted daily dose on life is compounded by broad daily temperature variations with sudden and sharp fluctuations. Lake habitat chemistry is highly dynamical with notable changes in yearly ion concentrations and pH resulting from low and variable yearly precipitation. The year-round combination of environmental variables define these lakes as end-members. In such an environment, they host ecosystems that include a significant fraction of previously undescribed species of zooplankton, cyanobacterial, and bacterial populations.

  3. The large lake ecosystems of northern Canada

    Microsoft Academic Search

    M. S Evans

    2000-01-01

    The Great Lakes of northern Canada are relatively understudied ecosystems in comparison to the better-investigated Laurentian Great Lakes. This chain of lakes extends north from Lake Winnipeg (a shallow prairie lake) to Wollaston Lake and Lake Athabasca (moderately deep arboreal lakes) to Great Slave Lake (a deep subarctic lake) to Great Bear Lake (a deep lake located in the Arctic

  4. Historic and modern abundance of wild lean lake trout in Michigan waters of Lake Superior: Implications for restoration goals

    USGS Publications Warehouse

    Wilberg, Michael J.; Hansen, Michael J.; Bronte, Charles R.

    2003-01-01

    Populations of lake trout Salvelinus namaycush in Lake Superior collapsed in the late 1950s due to overfishing and predation by sea lampreys Petromyzon marinus. A binational effort to restore the lean morphotype of lake trout began with the stocking of hatchery-reared fish followed by the chemical control of sea lampreys and closure of the commercial fishery. Previous comparisons of the contemporary abundance of wild lean lake trout with that from historic commercial fishery statistics indicate that abundance was higher historically. However, this conclusion may be biased because several factors- the inclusion of siscowet (the 'fat' morphotype of lake trout) in the catch statistics, the soak time of nets, seasonal effects on catch per effort, and the confounding effects of effort targeted at lake whitefish Coregonus clupeaformis- were not accounted for. We developed new indices of historic lean lake trout abundance that correct for these biases and compared them with the assessment data from 1984 to 1998 in Michigan waters of Lake Superior. The modern (1984-1998) abundance of wild lean lake trout is at least as high as that during 1929-1943 in six of eight management areas but lower in one area. Measures to promote and protect naturally reproducing populations have been more successful than previously realized.

  5. Bathymetry of Bonnie Doone Lake, Kornbow Lake, Mintz Pond, and Glenville Lake, Cumberland County, North Carolina, 1996-98

    USGS Publications Warehouse

    Giorgino, M.J.; Strain, R.E.

    1999-01-01

    Bathymetric surveys were conducted at four water-supply impoundments of Little Cross Creek in Cumberland County, North Carolina. The surveys were conducted in April 1996 at Mintz Pond and Glenville Lake, and in January 1998 at Bonnie Doone Lake and Kornbow Lake. The resulting bathymetric maps are the first to cover the entire range in depth for these reservoirs and provide a framework for future evaluations of bathymetry and storage capacity. Bathymetric maps were constructed from depth and position data collected at each reservoir. A boat-mounted, research-grade fathometer was used to record water depths with a vertical accuracy of 0.1 foot. At Mintz Pond and Glenville Lake, position was measured by using a wide-band laser tracking system interfaced with a total station survey instrument. This positioning method required multiple land-based control points to be established and was hampered by line-of-sight restrictions between the control points and the boat. At Bonnie Doone Lake and Kornbow Lake, a global positioning system was used to collect differentially corrected location data. This positioning method enabled more rapid data collection, eliminated the need for land-based control points, and provided improved data coverage. Spillway elevations range from 172.8 feet above mean sea level at Bonnie Doone Lake to 113.1 feet at Glenville Lake. Surface area and storage volume were computed for each reservoir and were related to water-surface elevations at 1-foot intervals. The combined surface acreage of the four Little Cross Creek reservoirs at their full-pool elevations is 120.97 acres, consisting of 21.20 acres at Bonnie Doone Lake, 47.09 acres at Kornbow Lake, 15.56 acres at Mintz Pond, and 37.12 acres at Glenville Lake. The four reservoirs have a combined usable storage capacity of 674.91 acre-feet, which is the sum of 127.93 acre-feet in Bonnie Doone Lake, 320.62 acre-feet in Kornbow Lake, 53.25 acre-feet in Mintz Pond, and 173.11 acre-feet in Glenville Lake.

  6. An event-driven phytoplankton bloom in southern Lake Michigan observed by satellite

    NASA Astrophysics Data System (ADS)

    Lesht, B. M.; Stroud, J. R.; McCormick, M. J.; Fahnenstiel, G. L.; Stein, M. L.; Welty, L. J.; Leshkevich, G. A.

    2002-04-01

    Sea-viewing Wide Field-of-View Sensor (SeaWiFS) images from June 1998 show a surprising early summer phytoplankton bloom in southern Lake Michigan that accounted for approximately 25% of the lake's annual gross offshore algal primary production. By combining the satellite imagery with in situ measurements of water temperature and wind velocity we show that the bloom was triggered by a brief wind event that was sufficient to cause substantial vertical mixing even though the lake was already stratified. We conclude that episodic events can have significant effects on the biological state of large lakes and should be included in biogeochemical process models.

  7. Physicochemical Characterization of Lake Spray Aerosol Generated from Great Lakes Water Samples

    NASA Astrophysics Data System (ADS)

    Ault, A. P.; Axson, J. L.; May, N.; Pratt, K.

    2014-12-01

    Wave breaking across bodies of water releases particles into the air which can impact climate and human health. Similar to sea spray aerosols formed through marine wave breaking, freshwater lakes generate lake spray aerosol (LSA). LSA can impact climate directly through scattering/absorption and indirectly through cloud nucleation. In addition, these LSA are suggested to impact human health through inhalation of these particles during algal bloom periods characterized by toxic cyanobacteria. Few studies have been conducted to assess the physical and chemical properties of freshwater LSA. Herein, we discuss constructing a LSA generation system and preliminary physical and chemical characterization of aerosol generated from water samples collected at various sites across Lake Erie, Lake Huron, Lake Superior, and Lake Michigan. Information on aerosol size distributions, number concentrations, and chemical composition will be discussed as a function of lake water blue-green algae concentration, dissolved organic carbon concentration, temperature, conductivity, and dissolved oxygen concentration. These studies represent a first step towards evaluating the potential for LSA to impact climate and health in the Great Lakes region.

  8. Mono Lake, California

    NSDL National Science Digital Library

    Sierra WebPage

    This Sierra Webpage is dedicated to Mono Lake, CA. It offers a brief description of Mono Lake, including photos and sightseeing tips, and features numerous writings by Mono Lake Park Ranger David Carle. Subjects include the Mono Lake environment, visiting the lake, and the water issue. An entry of particular interest is Strange Water- Mono Lake Gourmet: An Unusual Recipe. It includes 'Mock Mono Lake Soup' and 'Tufa Porridge Extraordinaire'- two recipes designed to illustrate the composition of Mono Lake and the chemical processes involved in tufa formation.

  9. Salinization and dilution history of ground water discharging into the Sea of Galilee, the Dead Sea Transform, Israel

    Microsoft Academic Search

    Gregory Bergelson; Ronit Nativ; Amos Bein

    1999-01-01

    The mechanism governing salinization of ground water discharging into the Sea of Galilee in Israel has been the subject of debate for several decades. Because the lake provides 25% of the water consumed annually in Israel, correct identification of the salt sources is essential for the establishment of suitable water-management strategies for the lake and the ground water in the

  10. Seismic Investigations of Lake Ladoga (Russia) -First Results

    NASA Astrophysics Data System (ADS)

    Krastel, S.; Wagner, B.; Melles, M.; Fedorov, G.

    2013-12-01

    A new joint German-Russian project aims at investigating the climatic and environmental history during Late Quaternary times along a more than 6000 km long longitudinal transect crossing northern Eurasia. For this purpose shallow and deep seismic surveys shall be carried out (from west to east) on the lakes Ladoga, Shuchye, Levinson-Lessing, Taymyr, and Emanda. Sediment cores will be taken based on the results of the seismic campaigns. The well-studied Lake El gygytgyn represents the eastern-most location of the transect and will act as reference site. In a first phase, we will investigate Lake Ladoga, which is located about 50 km east of St Petersburg. Lake Ladoga is the largest lake in Europe and covers an area of almost 18.000 km2. The modern sedimentation as well as the late glacial and Holocene history of the lake was studied in detail by the Russian Academy of Sciences Limnological Institute in St. Petersburg. The older lake history is only known from a transect drilled in the southern lake in the 1930ies. The cores of up to about 40 m length were only briefly described and are not existing any more. The results from these cores, known from unpublished reports only, show the existence of presumably marine Eemian sediments, representing the time when Ladoga Lake was part of a precursor of the Baltic Sea, which had a connection via Ladoga and Onega Lakes to the White Sea and further to the Arctic Ocean. A seismic survey using a Mini-GI-Gun and a 32-channel seismic streamer will be carried out in late August/early September 2013 in order to investigate the sedimentary and tectonic history of Lake Ladoga. The data will also be used to evaluate the potential of Lake Ladoga for a deep drilling campaign. First results of the seismic survey will be presented in the frame of this presentation.

  11. Recovery of an offshore lake trout (Salvelinus namaycush) population in eastern Lake Superior

    USGS Publications Warehouse

    Curtis, Gary L.

    1990-01-01

    The lake trout (Salvelinus namaucush) population at Stannard Rock, Michigan, an isolated offshore reef in eastern Lake Superior, was monitored each spring from 1959-79 using a permit assessment gill net fishery. This population, like nearly all of those in inshore waters, declined to low levels during the years of intense predation by the sea lamprey (Petromyzon marinus) in the late 1950's and early 1960's. After sea lamprey control began in 1961, the abundance of native lake trout at Stannard Rock began to increase slowly in the 1960's and was limited to recruitment into the fishable stock of native fish that were juveniles during the years of high sea lamprey activity. By the early 1970's lake trout abundance increased sharply and remained at a high level. This rapid recovery resulted from several strong year classes produced by the small spawning aggregations that reached maturity in the 1960's. Reproduction occurred in all years during and after the peak of sea lamprey activity in 1959. The strengths of year classes produced in 1963-1968 were related to the relative abundance of spawners the previous fall.

  12. TEACH Great Lakes

    NSDL National Science Digital Library

    The Education And Curriculum Home site (TEACH) is a new component of the Great Lakes Information Network, with a focus on advancing Great Lakes-related educational materials for the broad audience of educators and students in the Great Lakes region and beyond. TEACH features mini-lessons on Great Lakes topics: environment, history and culture, geography, pollution, careers, and business. Geared for elementary through high school students, the modules are continually expanded and updated and include links to a glossary to help explain scientific terms and acronyms. Also included is a section for questions and answers, and education links. Specific topics within the site include: Great Lakes native flora, water levels on the Great Lakes, native peoples of the Great Lakes region, Great Lakes law and policy, introduction to the Great Lakes, how the lakes were formed, Great Lakes shoreline geology, non-native species, and urban sprawl.

  13. Lake Effects: The Lake Superior Curriculum Guide.

    ERIC Educational Resources Information Center

    Beery, Tom; And Others

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

  14. Lake Trout Rehabilitation in Lake Huron

    Microsoft Academic Search

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

    1995-01-01

    Efforts to restore lake trout (Salvelinus namaycush) in Lake Huron after their collapse in the 1940s were underway in the early 1970s with completion of the first round oflampricide applications in tributary streams and the stocking of several genotypes. We assess results of rehabilitation and establish a historical basis for comparison by quantifying the catch of spawning lake trout from

  15. Recent lake ice-out phenology within and among lake districts of Alaska, U.S.A.

    USGS Publications Warehouse

    Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido

    2013-01-01

    The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. In lake-rich regions, the loss of ice cover also plays a key role in landscape and climatic processes. Thus, there is a need to understand lake ice phenology at multiple scales. In this study, we observed ice-out timing on 55 large lakes in 11 lake districts across Alaska from 2007 to 2012 using satellite imagery. Sensor networks in two lake districts validated satellite observations and provided comparison with smaller lakes. Over this 6 yr period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low inter-annual variability. Approximately 80% of the variation in ice-out timing was explained by the date of 0°C air temperature isotherm and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Coherence in ice-out timing within the lakes of each district was consistently strong over this 6 yr period, ranging from r-values of 0.5 to 0.9. Inter-district analysis of coherence also showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June–July) and climatology is sea-ice influenced. These patterns of lake ice phenology provide a spatially extensive baseline describing short-term temporal variability, which will help decipher longer term trends in ice phenology and aid in representing the role of lake ice in land and climate models in northern landscapes.

  16. 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 fluxes. A slight increase in precipitation coverage was noted over Lake Erie due to a decrease in ice cover. Both the RTG SST and the GLST products predicted the precipitation south of the actual location of precipitation. This single case study is the first part of an examination to determine how MODIS data can be applied to improve model forecasts in the Great Lakes region.

  17. Great Lakes RESTORATION

    E-print Network

    Great Lakes RESTORATION NATIONALOCEAN IC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM E R CE Great Lakes Restoration Initiative Recognizing the importance of the Great Lakes to our nation, President Obama made restoration a national priority. The resulting Great Lakes Restoration Initiative (GLRI

  18. Great Lakes RESTORATION

    E-print Network

    Great Lakes RESTORATION NATIONALOCEAN IC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM E R CE The Great Lakes Restoration Initiative Recognizing the importance of the Great Lakes to our nation, President Obama made their restoration a national priority. The resulting Great Lakes Restoration

  19. Great Lakes RESTORATION

    E-print Network

    Great Lakes RESTORATION NATIONALOCEAN IC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM E R CE Great Lakes Restoration Initiative Recognizing the importance of the Great Lakes to our nation, President Obama made their restoration a national priority. The resulting Great Lakes Restoration Initiative

  20. Magnitude and Significance of Carbon Burial in Lakes, Reservoirs, and Northern Peatlands

    USGS Publications Warehouse

    U.S. Geological Survey

    1999-01-01

    It is estimated that freshwater lakes in the world have a total area of about 1.5x1012 m2 (Shiklomanov, 1993; table 1). Including saline inland seas in this total would add another 1x1012 m2. The 28 largest (area of each > 5,000 km2) freshwater lakes in the world have a total area of 1.18x1012 m2 or about 79 percent of the total area of all freshwater lakes. If the 28 large lakes bury organic carbon (OC), on average, at the same rate as Lake Michigan (5 g/m2/yr), then the annual rate of OC burial in these 28 lakes is about 6 Tg/yr (6 terragrams per year or 6x1012 g/yr; table 1). If the smaller lakes bury OC, on average, at the same rate as an average Minnesota lake (72 g/m2/yr), then the annual rate of OC accumulation in these smaller lakes is about 23 Tg/yr (23x1012 g/yr; table 1). If saline inland seas bury OC at the Lake Michigan rate, this would be an additional 5 Tg/yr, for a total of 34 Tg/yr for all freshwater lakes and saline inland seas (table 1). Mulholland and Elwood (1982) estimated the OC burial in all lakes and inland seas (excluding the Black Sea) to be 60 Tg/yr today (table 1) and an average of 20 Tg/yr for the last 10,000 years. Stallard (1998) modeled terrestrial sedimentation as a series of 864 scenarios. For lake area, he used 1.54x1012 m2, the area of the 250 largest lakes in the world. This is close to the total of large and small lakes given in table 1. Again, including inland seas to this total would add an additional 1x1012 m2. Results of scenarios for lakes and reservoirs were divided into two components, those with clastic sediments and those with organic sediments. The results of OC burial in the most likely of Stallard's scenarios for lakes range from 48 to 72 Tg/yr (table 1), the average of which is close to the 60 Tg/yr estimated by Mulholland and Elwood (1982). We will use an average of 54 Tg/yr (table 1). The closeness of these estimates, calculated by different methods, suggests that this value is not in error by more than a factor of two.

  1. Population biology of lake trout (Salvelinus namaycush) of Lake Superior before 1950

    USGS Publications Warehouse

    Sakagawa, Gary T.; Pycha, Richard L.

    1971-01-01

    Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10-0.25. The Ricker model was used to calculate yield per recruitment, which varied with natural mortality and growth. Natural mortality was more critical than growth; yield per recruitment increased 183.3% with a 60% decrease in instantaneous natural mortality (from 0.25 to 0.10). For the prelamprey lake trout population the yield per recruitment was about 12-34 lb; the recruitment of about 3.6-10.1 million lake trout of age 1.5 resulted in an annual commercial production of 4 million lb.

  2. Connection between Caspian Sea level variability and ENSO

    Microsoft Academic Search

    K. Arpe; L. Bengtsson; G. S. Golitsyn; I. I. Mokhov; V. A. Semenov; P. V. Sporyshev

    2000-01-01

    The problem of the world greatest lake, the Caspian Sea level, changes attracts the increased attention due to its environmental consequences and unique natural characteristics. Despite the huge number of studies aimed to explain the reasons of the sea level variations the underlying mechanism has not yet been clarified. The important question is to what extent the CSL variability is

  3. Dramatic Evaporation of the Aral Sea

    NSDL National Science Digital Library

    Joycelyn Thomson

    2001-04-19

    DISAPPEARING WATER: THE ARAL SEA OVER TIME, FROM 1973 TO 2001 A time series is a powerful illustrative tool. Where in the case of Las Vegas we see the direct effects of people on the land, in the case of the Aral Sea, separating the countries of Kazakhstan and Uzbekistan, we see indirect, but no less dramatic effects on a different part of the world. The Aral Sea is actually not a sea at all. It is an immense lake, a body of fresh water, although that particular description of its contents might now be more a figure of speech than practical fact. In the last thirty years, more than sixty percent of the lake has disappeared. As youll see in the visualization, the change over time is dramatic. In the 1970s, farmers and state offices opened significant diversions from the rivers supplying water to the lake, sending millions of gallons to irrigate cotton fields and rice paddies. So voluminous were these irrigation sluices that concentrations of salts and minerals began to rise in the shrinking body of water. That change in chemistry has led to staggering alterations in the lakes ecology, causing precipitous drops in the Arals fish population. A secondary effect of this reduction in the Aral Seas overall size is the rapid exposure of the lake bed. Powerful winds that blow across this part of Asia routinely pick up and deposit tens of thousands of tons of now exposed soil every year. This has not only contributed to significant reduction in breathable air quality for nearby residents, but also appreciably affected crop yields due to those heavily salt laden particles falling on arable land. In the following sequence of images, we see a series of Landsat scenes taken several years apart. As the years pass, we see the profound reduction in overall area covered by the Aral, and a commensurate increase in land area as the floor of the sea now lies exposed.

  4. The Great Lakes Atlas

    NSDL National Science Digital Library

    Lee Botts

    This is an online version of the text, The Great Lakes: An Environmental Atlas and Resource Book. Taking an ecosystem approach, the Atlas helps readers understand the Great Lakes and other natural resources in the Great Lakes region as an interdependent system across an international border. Its purpose is to demonstrate how the Great Lakes are affected by use and to increase public appreciation for the importance of these lakes as a North American and global resource. A French version is available.

  5. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... Multi-angle Imaging SpectroRadiometer (MISR) image of the Red Sea was acquired on August 13, 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of algae,  Trichodesmium ...

  6. Chemical composition of the sediment from Lake 20 (Antarctica)

    Microsoft Academic Search

    Renato BAUDO; Paola BARBERO; Monica BELTRAMI; Daria ROSSI

    Lake 20 (19,000 m2) is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention

  7. Using Real-World Data to Examine Climate Change Implications for Lake Superior

    NSDL National Science Digital Library

    This activity was developed during the workshop, Teaching Climate Change: Insight from Large Lakes, held in June 2012.by Diane Desotelle, MN Sea GrantKevin Theissen, University of St. ThomasTopic: Climate change ...

  8. Automatic Temporal Tracking of Supra-Glacial Lakes

    NASA Astrophysics Data System (ADS)

    Liang, Y.; Lv, Q.; Gallaher, D. W.; Fanning, D.

    2010-12-01

    During the recent years, supra-glacial lakes in Greenland have attracted extensive global attention as they potentially play an important role in glacier movement, sea level rise, and climate change. Previous works focused on classification methods and individual cloud-free satellite images, which have limited capabilities in terms of tracking changes of lakes over time. The challenges of tracking supra-glacial lakes automatically include (1) massive amount of satellite images with diverse qualities and frequent cloud coverage, and (2) diversity and dynamics of large number of supra-glacial lakes on the Greenland ice sheet. In this study, we develop an innovative method to automatically track supra-glacial lakes temporally using the Moderate Resolution Imaging Spectroradiometer (MODIS) time-series data. The method works for both cloudy and cloud-free data and is unsupervised, i.e., no manual identification is required. After selecting the highest-quality image within each time interval, our method automatically detects supra-glacial lakes in individual images, using adaptive thresholding to handle diverse image qualities. We then track lakes across time series of images as lakes appear, change in size, and disappear. Using multi-year MODIS data during melting season, we demonstrate that this new method can detect and track supra-glacial lakes in both space and time with 95% accuracy. Attached figure shows an example of the current result. Detailed analysis of the temporal variation of detected lakes will be presented. (a) One of our experimental data. The Investigated region is centered at Jakobshavn Isbrae glacier in west Greenland. (b) Enlarged view of part of ice sheet. It is partially cloudy and with supra-glacial lakes on it. Lakes are shown as dark spots. (c) Current result. Red spots are detected lakes.

  9. Holocene Cyclical Switching of Colorado River Water Alternatively to the Sea of Cortez or to the Salton Sink

    Microsoft Academic Search

    K. A. Howard; G. M. Stock; T. K. Rockwell; J. Schafer; R. H. Webb

    2007-01-01

    The former giant lake (ancient Lake Cahuilla) that intermittently filled the Salton Sink with a volume half that of Lake Erie has profound implications for the hydrologic and ecologic history of the Colorado River delta. Because the delta dams and isolates the sink from the Sea of Cortez (Gulf of California), the delta cone has a rare geometry that drains

  10. Petroleum and chlorinated hydrocarbons in water from Lake Manzala and associated canals

    SciTech Connect

    Badawy, M.I.; Wahaab, R.A.; Abou Waly, H.F. [National Research Centre, Cairo (Egypt)

    1995-08-01

    Lake Manzala is located at the north eastern edge of Nile Delta in Egypt. It is separated from the Mediterranean sea by a sandy beach ridge. However, the lake is in connection with the sea through three opening nearby Port Said. The area of the lake is about 769 Km{sup 2} and relatively shallow with an average depth of 1.3 m. The lake is of high economic value as a natural resource, for fishery, reacreation and for migratory birds. The lake is highly polluted as it receives wastewaters discharged by several canal. The present investigation aimed to assess the residue levels of petroleum hydrocarbons, chlorinated insecticides and polychlorinated biphenyls in the lake water as well as in Hadous canal, Fariskur canal and Bahr-El-Baqar canal. 9 refs., 1 fig., 3 tabs.

  11. [Decompression problems in diving in mountain lakes].

    PubMed

    Bühlmann, A A

    1989-08-01

    The relationship between tolerated high-pressure tissue nitrogen and ambient pressure is practically linear. The tolerated nitrogen high pressure decreases at altitude, as the ambient pressure is lower. Additionally, tissues with short nitrogen half-times have a higher tolerance than tissues which retain nitrogen for longer duration. For the purpose of determining safe decompression routines, the human body can be regarded as consisting of 16 compartments with half-times from 4 to 635 minutes for nitrogen. The coefficients for calculation of the tolerated nitrogen-high pressure in the tissues can be deduced directly from the half-times for nitrogen. We show as application the results of 573 simulated air dives in the pressure-chamber and 544 real dives in mountain lakes in Switzerland (1400-2600 m above sea level) and in Lake Titicaca (3800 m above sea level). They are in accordance with the computed limits of tolerance. PMID:2799365

  12. 29 CFR 784.130 - “At sea.”

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...technical or special meaning. For example, to define “at sea” to include only bodies of water subject to the ebb and flow of the tides or to saline waters would exclude the Great Lakes which obviously would not comport with the legislative intent. On the other...

  13. Trends in Water Clarity of the Lower Great Lakes from Remotely Sensed Aquatic Color

    Microsoft Academic Search

    Caren E. Binding; John H. Jerome; Robert P. Bukata; William G. Booty

    2007-01-01

    Satellite observations of aquatic colour enable environmental monitoring of the Great Lakes at spatial and temporal scales not obtainable through ground-based monitoring. By merging data from the Coastal Zone Color Scanner (CZCS) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), monthly binned images of water-leaving radiance over the Great Lakes have been produced for the periods 1979–1985 and 1998–2006. This time-series

  14. Warming Drops Great Lakes to Historic Lows

    NSDL National Science Digital Library

    2000-04-27

    As part of this lesson plan, students will be asked to read a news article and to construct and explain theories for the decline of the water level of the Great Lakes. They should be able to locate the Great Lakes on a map, compare them to lakes in other parts of the world, hypothesize what might happen in the short term if global temperatures continue to rise, and to consider these seemingly contradictory events: water is evaporating and levels are declining in some places in the world, while polar melting is causing sea levels to rise. Students form groups and develop a theory, supported by at least three pieces of evidence, to explain the water level decline and present their theories to the class.

  15. Limnology of Gallocanta Lake, Aragon, northeastern Spain

    Microsoft Academic Search

    F. A. Comín; M. Alonso; P. Lopez; M. Comelles

    1983-01-01

    A limnological study was sustained from September 1980 to October 1981 to show the evolution of Gallocanta Lake (N.E. Spain) under very dry climatic conditions. It is the physical terminus within an endorheic basin of 500 km2 situated 1 000 m over the sea level. In 1977 its maximum depth was 2.5 m but it decreased to 60 cm in

  16. U.S. Federal Research on Fisheries and Limnology in the Great Lakes through

    E-print Network

    528 U.S. Federal Research on Fisheries and Limnology in the Great Lakes through 1964: An Annotated, Donald L. McKernan, Director U.S. Federal Research on Fisheries and Limnology in the Great Lakes through The research program, 1957-64 1 Sea lamprey 1 Fisheries and limnology 4 Publications by staff members 5

  17. Oceanography of a tidally choked fjord: Lake Melville, Labrador

    NASA Astrophysics Data System (ADS)

    deYoung, Brad; Lu, Zhaoshi; Demirov, Entcho

    2013-04-01

    Lake Melville is large and complex sub-Arctic fjord that is a major outlet for freshwater on the Labrador coast. Although it has been the subject of exploration for centuries, we still know relatively little about its oceanography. We are studying the influence of changes in the fresh water discharge on the dynamics and ecosystem of Lake Melville in Labrador and how they interact with long-term climatic variability. Enormous hydroelectric developments have changed the freshwater runoff dynamics with unknown implications for the local and regional oceanography. The fjord is tidally choked, leading to intense flows at the entrance of 3-4 m/s. We will review the role of mixing and seasonal cycles in determining water properties in the lake and how changing climatic and freshwater conditions influence the oceanography and sea-ice dynamics. We will present historical data for the Lake together with results from our recent oceanographic work. We will compare our current measurements with results of a high resolution, variable element, coupled ocean-ice model for the Lake. The long-term exchange between the Labrador Sea and Lake Melville will be studied with this high-resolution ocean model. The implications of interannual ocean and atmospheric variability on the Lake ocean ecosystem will be discussed.

  18. Lake Trout Movements in Northwestern Lake Michigan

    Microsoft Academic Search

    Patrick J. Schmalz; Michael J. Hansen; Mark E. Holey; Patrick C. McKee; Michael L. Toneys

    2002-01-01

    We quantified the distance that lake troutSalvelinus namaycushmoved in northwestern Lake Michigan and examined (1) the directional preference and (2) the effect of population density on movement. Lake trout were captured in spring and fall 1983-1996, tagged with Floy anchor tags, and recaptured during subsequent agency sampling and by commercial fishers and anglers during 1983-1997. Angler recaptures were used to

  19. The 5 Great Lakes: HOMES

    NSDL National Science Digital Library

    2012-04-21

    You will review these five websites and complete a flow chart for each of the five Great Lakes. Project Organizer: Flow Chart First, you will learn about Lake Huron. Go to Lake Huron to learn more about this great lake.Complete a Flow Chart Flow Chart for Lake Huron. Write "Lake Huron" under Topic and include five supporting details you learned ...

  20. Climatic change and evaporative processes in the development of Common Era hypersaline lakes, East Antarctica: A study of Lake Suribati

    NASA Astrophysics Data System (ADS)

    Nakashima, H.; Seto, K.; Katsuki, K.; Kaneko, H.; yamada, K.; Imura, S.; Dettman, D. L.

    2011-12-01

    The Antarctic continent was uplifted by glacioisostatic rebound due to the regression of ice sheets after the last glacial period. Today's saline lakes were formed in shallow basins originally below sea level. Antarctic hypersaline lakes are formed by concentration of isolated seawater bodies as affected by recent climate change. Many saline lakes are found in the ice-free area of the Soya coast, East Antarctica. Lake Suribati is located in Sukarvsnes on the Soya coast. It is a hypersaline lake with maximum salinity ~200 psu, and an observable stable halocline at 7~12m depth. This study uses Lake Suribati sediment core Sr4C-01, collected by the 46th Japanese Antarctica Research Expedition, to examine the relationship of climatic change to evaporative processes and solute concentration in Lake Suribati in the Common Era. Sr4C-01 core was collected at 9.53m water depth in Lake Suribati in 2005 (core length is 63cm). This core primarily consists of black mud and laminated black organic mud. In the interval from 10 to 24cm below the sediment surface evaporite crystals occur. The age of the Sr4C-01 core bottom is estimated to be ~3,500 cal yrs BP, based on AMS carbon-14 dating at 6 core horizons. The evaporite crystals were indentified as aragonite based on XRD. Total inorganic carbon (TIC) content is low, around 0.5%, throughout the Sr4C-01 core, with higher values, approximately 1~4%, in two intervals, 57~52cm and 29~10cm core depth. Variation in CaO content tracks TIC content. We suggest that synchronous change in CaO and TIC contents indicate the vertical change in the amount of aragonite. Two intervals of evaporite precipition imply two intervals of evaporation and concentration of lake water. Hypersaline lake conditions did not occur soon after the isolation from the sea, rather these occurred under repeated concentration and dilution of lake water. Dilution of saline lake water could occur through the inflow of melt water from local snow or ice, indicating a warm climate interval. During cool periods, local snow and ice sheet may have remained frozen. In this case, lake water volume would decrease by sublimation from the frozen lake surface, leading to salt concentration. Based on MgO and Na2O content data, we suggest that other Mg and Na evaporites occur in the core. If such evaporates can be identified, a detailed solute concentration process can be described. Analysis of evaporites in sediment core from Antarctic hypersaline lakes have great potential as proxy indicators for the study of climate change in Antarctica.

  1. Investigation of the sand sea with the tallest dunes on Earth: China's Badain Jaran Sand Sea

    NASA Astrophysics Data System (ADS)

    Dong, Zhibao; Qian, Guangqiang; Lv, Ping; Hu, Guangyin

    2013-05-01

    China's Badain Jaran Sand Sea features the tallest dunes on Earth and a unique mega-dune-lake landscape. It had been explored little until the 1990s, though early scientific explorations surrounding the sand sea had begun by the early 20th century. Heated debates now focus on the desert environment, and particularly how the mega-dunes and desert lakes develop and evolve. This paper reviews the status of these debates and summarizes the supporting evidences. The environmental research mainly concerns formation and evolution of the sand sea, and its relationship with climate change. The proposed formation time ranges from the Early Pleistocene to the Holocene. Opinions vary about climate change on different time scales. The reconstructed climate change history is shorter than the sand sea's history, with the longest record extending to the Late Pleistocene. The mega-dune research focuses on sediments, dune morphology, and formation processes. It remains unclear whether the mega-dunes result primarily from wind action, control by the underlying topography, or groundwater maintenance. The sources of lake water are also debated, but there are four main hypotheses: atmospheric precipitation, groundwater from nearby areas, precipitation and snowmelt in remote areas such as the Qilian Mountains and the Qinghai-Tibetan Plateau, or paleowater that formed during past periods of wet climate. We believe that the sand sea deserves further study in terms of its dune geomorphology, evolution, and hydrology, and their responses to climate change. Meteorological and hydrological observations and monitoring in the sand sea are particularly necessary.

  2. Sea Stars

    NSDL National Science Digital Library

    2012-07-28

    At first glance, starfish, more properly called sea stars, aren’t doing much of anything. In this video, Jonathan’s investigations reveal a slow-motion predator that hunts and attacks its prey. Traveling the world, Jonathan investigates sea stars from the tropics to the Antarctic and uses time-lapse photography to reveal an amazing complexity to the world of the sea star. Please see the accompanying study guide for educational objectives and discussion points.

  3. Sea Chest

    NSDL National Science Digital Library

    By exploring life at sea for sailors and passengers, the Maritime Museum of San Diego offers insight into the history of maritime exploration, emigration, and commerce. Background and classroom activities are applicable to history, geography, social studies, science, art and other subjects. Emphasis on 19th Century sea travel and sailing ships, with topics including navigation techniques and technology, sailor's crafts, health and medicine at sea, shipboard life and social interactions.

  4. Characterization of Organic Phosphorus Form and Bioavailability in Lake Sediments using P Nuclear Magnetic Resonance and Enzymatic Hydrolysis.

    PubMed

    Giles, Courtney D; Lee, Lydia G; Cade-Menun, Barbara J; Hill, Jane E; Isles, Peter D F; Schroth, Andrew W; Druschel, Gregory K

    2015-05-01

    Lake sediments are known to be a significant source of phosphorus (P) to plankton populations under certain biogeochemical conditions; however, the contribution of sediment organic P (P) to internal P loads remains poorly understood. We investigated P speciation and bioavailability in sediments collected over multiple months from a shallow, eutrophic bay in Lake Champlain (Missisquoi Bay, VT) using solution P nuclear magnetic resonance (NMR) spectroscopy and enzymatic hydrolysis (EH) analysis of sediments collected during years with (2008) and without (2007) algal blooms. Sediments collected during bloom onset (July) and peak bloom (August) months contained the largest proportion of enzyme-labile P, whereas pre- and postbloom sediments were primarily composed of nonlabile P. Monoester P to diester P ratios changed with respect to depth, particularly during bloom periods. Monoester P and DNA accumulation, likely from settling particulate matter, began at the onset of the bloom and continued into October 2008 during the postbloom period. The disappearance of inositol hexakisphosphate stereoisomers and the generation of orthophosphate at lower sediment depths was also evident in August 2008. Principal components analysis of EH and NMR species proportions confirmed differences between sediment cores collected during bloom onset and peak bloom, compared with pre- and postbloom sediments. Large enzyme-labile and P species proportions corresponded to increased sediment P flux and reduced manganese and iron species in porewater. These findings suggest that interseasonal changes in P speciation may influence P mobility in sediments and contribute to important feedback dynamics between biological productivity and sediment water interface geochemistry. PMID:26024268

  5. 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 ...

  6. Quebec: Lake Manicouagan

    Atmospheric Science Data Center

    2013-04-17

    ... lake is bounded by erosion-resistant metamorphic and igneous rocks, and shock metamorphic effects are abundant in the target rocks of the crater floor. Today Lake Manicouagan serves as a reservoir and is ...

  7. Lake Ice phenology of small lakes: Impacts of climate variability in the Great Lakes region

    Microsoft Academic Search

    Vimal Mishra; Keith A. Cherkauer; Laura C. Bowling; Matthew Huber

    2011-01-01

    Formation of lake ice is common in lakes located in mid and high latitudes. Lake ice plays a vital role in heat storage, controlling lake water temperature, survival of aquatic ecosystems, and maintaining the bio diversity of lakes. Significant warming in air temperature during the cold season (October–May) may lead to reduced ice cover of lakes and eventually disturb the

  8. Lake-Effect Snowfall over Lake Michigan.

    NASA Astrophysics Data System (ADS)

    Braham, Roscoe R., Jr.; Dungey, Maureen J.

    1995-05-01

    Aircraft measurements of snow particle size spectra from 36 flights on 26 snowy days are used to estimate snow precipitation rates over Lake Michigan. Results show that average rates during 14 wind-parallel-type lake-effect storms increased from the upwind shore to about midlake and then were essentially uniform (1.5 2 mm day1, liquid water equivalent) to the downwind shore. Snow from midlake bands and shoreline bands maximized over the lake. The position of the maximum during these types of lake-effect storms depends on meteorological conditions. In any given case it may be near either shore or anywhere between them. This study combines 12 cases of midlake and shoreline bands. The resulting cross-lake snow profile shows a broad maximum reaching over 4 mm day1 near midlake. The single sample maximum snow precipitation rate encountered in this study was 77.7 mm day1. The average cross-lake profile from combining 26 cases of lake-effect storms shows that snowfall into the lake is considerably greater than one would expect from a linear interpolation between values measured along either shore.An attempt is made to estimate the average increase in snow over lake Michigan resulting from combined lake-effect and large-scale cyclonic storms. The result is interesting but not considered very reliable because it depends upon the relative frequencies of different types of lake-effect storms as well as overtake snow rates from large-scale cyclonic storms; neither is well known.

  9. The tectonic framework of a complex pull-apart basin: seismic reflection observations in the Sea of Galilee, Dead Sea transform

    Microsoft Academic Search

    Shaul Hurwitz; Zvi Garfunkel; Yuval Ben-Gai; Margaret Reznikov; Yair Rotstein; Haim Gvirtzman

    2002-01-01

    A multi-channel seismic reflection survey consisting of 20 lines with a total length of 180 km was conducted in the Sea of Galilee. The data provide new insights into the Pliocene–Quaternary evolution of the Kinarot–Beit–Shean pull-apart basin (KBSB) along the Dead Sea transform. Two distinct zones are defined beneath the lake: (1) a graben that underlies most of the lake,

  10. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

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

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

  11. Great Lakes NATIONALOCEAN

    E-print Network

    Great Lakes NATIONALOCEAN IC AND ATMOSPHERIC ADMINISTRATION U.S. D EPARTMENT OF COMM E R CE CoastWatch is a nationwide NOAA program in which the Great Lakes Environmental Research Laboratory (GLERL) functions as the Great Lakes regional node. GLERL obtains, produces, and delivers environmental data and products

  12. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

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

  13. Exploding Lakes in Cameroon

    USGS Multimedia Gallery

    In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows the Lake Nyos pipe ...

  14. Exploding Lakes in Cameroon

    USGS Multimedia Gallery

    In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. A small CO2 cloud from Lake Monoun k...

  15. LAKE COLUSA SAN JOAQUIN

    E-print Network

    Marysville Nevada City Downieville Auburn Coloma Placerville Soda Springs Tahoe Vista South Lake Tahoe DEL NORTE SISKIYOU MODOC LASSEN BUTTE PLUMAS GLENN LAKE COLUSA SUTTER YUBA NEVADA SIERRA PLACER EL LAKE COLUSA SUTTER YUBA NEVADA SIERRA PLACER EL DORADO AMADOR SONOMA NAPA YOLO CALAVERAS SAN JOAQUIN

  16. Lake Survey DETROIT, MICH.

    E-print Network

    ; · Lake Survey Center DETROIT, MICH. NOAA TM NOS LSC 06 NOAA Technical Memorandum NOS LSC 06 U. S Winter 1971_72 R. A. Ass.,i Lake Survey Center National Ocean Survey, NOAA Detroit, Michigan I ABSTRACT. Thirty-fi ve ice charts were produced from data collected on 23 Lake SUrvey Center ice reconnai5sance fli

  17. Investigating aquatic ecosystems of small lakes in Khorezm, Uzbekistan

    USGS Publications Warehouse

    Saito, L.; Scott, J.; Rosen, M.; Nishonov, Bakhriddin; Chandra, S.; Lamers, John P.A.; Fayzieva, Dilorom; Shanafield, M.

    2009-01-01

    The Khorezm province of Uzbekistan, located in the Aral Sea Basin, suffers from severe environmental and human health problems due to decades of unsustainable land and water management. Agriculture is the dominant land use in Khorezm, and agricultural runoff water has impacted many small lakes. In this water-scarce region, these lakes may provide a water source for irrigation or fish production. Samples have been collected from 13 of these lakes since 2006 to assess water quality, the aquatic food web, and possible limits to aquatic production. Lake salinity varied from 1 to >10 g/L both between and within lakes. Although hydrophobic contaminants concentrations were low (82-241 pg toxic equivalents/mL in June 2006, October 2006, and June 2007), aquatic species diversity and relative density were low in most lakes. Ongoing work is focused on 4 lakes with pelagic food webs to estimate fish production and assess anthropogenic impacts on the food web. Lake sediment cores are also being examined for organic contaminants, and hydrology is being assessed with stable isotopes. ?? 2009 ASCE.

  18. Sea Turtles

    NSDL National Science Digital Library

    2012-07-26

    In Malaysia there is an island known for more sea turtles than virtually anywhere on Earth. In this video, Jonathan visits this amazing ecosystem to learn about the life cycle of sea turtles. He is surprised to discover an amazingly complex and competitive environment. Please see the accompanying study guide for educational objectives and discussion points.

  19. Doughnut in the desert: Late-winter production pulse in southern Lake Michigan W. Charles Kerfoot

    E-print Network

    Doughnut in the desert: Late-winter production pulse in southern Lake Michigan W. Charles Kerfoot and unstratified waters, sea-viewing wide field-of-view sensor (SeaWiFS) and moderate-resolution imaging sediment capture, and deep-water productivity. The pulse may explain how certain zooplankton species

  20. Cryosat-2 thickness retrievals of freshwater lake ice

    NASA Astrophysics Data System (ADS)

    Beckers, J. F.; Casey, J. A.; Haas, C.

    2014-12-01

    The European Space Agency's (ESA) Cryosat mission was launched to improve our knowledge of the trends in the thickness of sea ice and glaciers. The new Synthetic Aperture processing method allows for significantly enhanced along-track resolution compared to traditional pulse-limited radar altimeters. Satellite observations have revealed rapid changes in the duration of the seasonal snow and ice cover of subarctic lakes. The often smooth, homogeneous ice cover of lakes is an excellent target for detailed studies of radar altimeter and imaging radar backscatter behavior. Furthermore, there is only limited information available regarding the changes in ice thickness of these lakes. Here we present and validate a method to retrieve the thickness of lake ice using CryoSat L1B data. In contrast to sea ice measurements where ice thickness is derived from isostatic freeboard retrievals, we obtain ice thickness from radar returns from both the ice surface and bottom, assuming that CryoSat's Ku-band radar pulses can penetrate through freshwater ice. The seasonal evolution of ice thickness of Great Bear Lake and Great Slave Lake, two large lakes in northern Canada, thus observed is compared to in-situ measurements, SAR imagery, scatterometer data, the results of a freezing-degree-day model, and previous studies. These confirm that the Ku-band signal often penetrates through the low-loss freshwater ice and is scattered from both the snow/ice and the ice/water interfaces. We examine the data for scattering from within the snow pack and the ice as this introduces uncertainty in the retrieval of ice thickness by masking the signal from snow/ice or ice/water interfaces. Although not designed for freshwater lake ice studies, CryoSat-2 and future SAR/SARIN mode satellite altimeter missions offer new possibilities to monitor Arctic and sub-Arctic lakes.

  1. Mono Lake Web Site

    NSDL National Science Digital Library

    Greg Reis

    Mono Lake Web Site is the homepage of the Mono Lake Committee and offers helpful information regarding the unique hypersaline and alkaline environment. Visitors will find information about the Mono Lake Committee, natural and political histories of the area, related water policies, a photo gallery with image descriptions, and links to related sites- including a clearinghouse. Those interested in Mono Basin birds will find sightings, counts, bird walks, and other related information. An additional feature, Mono Lake Live, offers up-to-the-minute data on road conditions, satellite images, weather, lake level, bird sightings, snow pack, and earthquakes.

  2. Food of lake trout in Lake Superior

    USGS Publications Warehouse

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

    1965-01-01

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

  3. Seismic Data Reveal Lake-Level Changes in Lake Issyk-Kul, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Gebhardt, C.; Spiess, V.; Keil, H.; Sauermilch, I.; Oberhänsli, H.; Abdrakhmatov, K.; De Batist, M. A.; Naudts, L.; De Mol, L.

    2013-12-01

    Lake Issyk-Kul is located in an intramontane basin of the Tien Shan, Kyrgyzstan, Central Asia, at 1607 m above sea level. It has formed in a tectonically active region with W-E striking major thrust zones both N and S of the lake. The lake is elongated with 180 km in W-E and 60 km in S-N direction and a water depth of roughly 670 m at its central plain. With a surface area of 6232 km2 and a total water colume of around 1736 km3, Lake Issyk-Kul is the second largest lake in the higher altitudes (De Batist et al., 2002). Two large delta areas have formed at the E and W end. Steep slopes at both the N and S shore separate rather narrow, shallow shelf areas from the central deeper plain. First seismic data of lake Issyk-Kul were acquired in 1982 by the Moscow University with a total of 31 profiles across the lake. In 1997 and 2001, a second and third seismic survey of the lake were carried out by the group of Marc De Batist (Ghent, Belgium) in cooperation with the Royal Museum of Central Africa (Tervuren, Belgium) and the SBRAS (Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia) using a sparker system with a single-channel streamer. These surveys were recently completed by a fourth expedition carried out by the University of Bremen in April 2013. During this expedition, 33 additional profiles were acquired with an airgun and a multi-channel streamer. The sparker surveys mostly cover the delta and shelf areas in high detail, while the airgun survey covers the deeper parts of the lake with penetration beyond the first multiple. Bathymetry data reveal that at the delta areas, the shelf is divided into two parts. The shallower comprises the part down to 110 m water depth with an average inclination of 0.5°, while the deeper part reaches from 110 m to 300 m water depth with an average slope inclination of 1°. Incised paleo-river channels of up to 2-3 km width and 50 m depth are visible both on the eastern and western shelf, but are limited to the shallower part of the deltas. They lie in the prolongation of modern river mouths at the eastern part of the lake, while at the western lake, they connect to former in- and outlets of the Chu River that is currently bypassing the lake (De Mol, 2006). A series of morphological terraces interpreted as ancient shorelines characterize the deeper part of the shelf. Together with lake-level terraces that are outcroping along the lake shores, the delta areas document up to 400 m of lake-level change. Deeper-penetrating multi-channel airgun profiles reveal that the sediments are mostly well-layered at least down to the multiple, and large-scale debris flows were detected only in some spots. The dipping of the layers increases with depth and reveals a halfgraben structure filled with lacustrine sediments. References: De Batist, M., et al., 2002. Bathymetry and sedimentary environments of Lake Issyk-Kul, Kyrgyz Republic (Central Asia): a large, high-altitude, tectonic lake. In: J. Klerkx and B. Imanackunov (Editors), Lake Issyk-Kul: Its Natural Environment. NATO Science Series, Series IV: Earth and Environmental Sciences. Kluwer Academic Publishers, Dordrecht, pp. 101-123. De Mol, L., 2006. Reconstructie van meerspiegelschommelingen in het Issyk-Kul Meer (Kirgizië) op basis van de geomorfologische en seismostratigrafische analyse van rivierdelta's. M.Sc. Thesis, University of Gent, Gent, 144 pp.

  4. Cytochrome P4501A expression, chemical contaminants and histopathology in roach, goby and sturgeon and chemical contaminants in sediments from the Caspian Sea, Lake Balkhash and the Ily River Delta, Kazakhstan

    Microsoft Academic Search

    Michael J. Moore; Igor V. Mitrofanov; Stefanie S. Valentini; Vjacheslav V. Volkov; Aleksey V. Kurbskiy; Elena N. Zhimbey; Lorraine B. Eglinton; John J. Stegeman

    2003-01-01

    Roach, goby and sturgeon were examined for cytochrome P4501A (CYP1A) expression and histopathology, in relation to contaminant burdens in fish and sediment. Gradients of induction of CYP1A were observed. Roach from the Ural and Ily River Deltas and roach and goby from the two stations nearest the Caspian Sea oil fields displayed higher levels of CYP1A expression in several organs

  5. Sea growth of anadromous brown trout ( Salmo trutta)

    NASA Astrophysics Data System (ADS)

    de Leeuw, J. J.; ter Hofstede, R.; Winter, H. V.

    2007-08-01

    Sea growth rates were studied in anadromous brown trout caught in Lake IJsselmeer, The Netherlands. Growth in the first year at sea was estimated at 26 cm from length-frequency distributions, and at 21 cm from back-calculated growth rates from scale readings. These estimates are considerably higher than sea growth rates observed in populations at higher latitudes (Norway, Sweden), but compare well with the limited information on sea growth rates estimated for anadromous trout in the River Rhine and rivers in Normandy (France).

  6. Abnormal tooth development in a sea lamprey

    USGS Publications Warehouse

    Manion, Patrick J.; Hanson, Lee H.

    1977-01-01

    Sea lampreys en route to their spawning grounds have been captured at mechanical or electrical structures that have been in operation for 1 to 27 spawning seasons (1949-75) on some 167 tributaries of the upper Great Lakes; more than 750,000 were taken in 1949-70 (Smith 1971). Among these lampreys (all of which were routinely examined at the time of capture) was one female (length, 434 mm; weight, 130 g) with markedly underdeveloped teeth. It was captured in May 1968 at an electrical barrier in the Ocqueoc River, a Michigan tributary of Lake Huron

  7. A surface tow net for collection of parasitic-phase sea lampreys

    USGS Publications Warehouse

    Dahl, Frederick H.

    1968-01-01

    A STUDY OF MIGRATORY BEHAVIOR of parasitic sea lampreys (Petromyzon marinus) in the Great Lakes required a means of capturing lampreys for tagging and releasing in St. Marys River, Lake Huron. Smith and Elliott (1953) fished specially made gill and trap nets for sea lampreys, but stationary nets could not be used in the St. Marys River because of boat traffic, interference with sport fishermen, and fast currents.

  8. Illinois-Indiana Sea Grant K-12 Education Resources

    NSDL National Science Digital Library

    This collection of Illinois-Indiana Sea Grant education resources includes several activities that introduce students to invasive species and seafood contamination. The goal of these activities is to educate not only students but adults on the issues of the Great Lakes. These resources also offer a multi-disciplinary approach to learning by integrating science with content areas such as math, language arts, geography, and the cultural arts. Resources are applicable to regions outside the Great Lakes.

  9. MODELING SALINITY BALANCE IN PROPOSED SALTON SEA RESTORATION USING A DIKED IMPOUNDMENT

    E-print Network

    Ponce, V. Miguel

    MODELING SALINITY BALANCE IN PROPOSED SALTON SEA RESTORATION USING A DIKED IMPOUNDMENT Victor M into main lake and diked impoundment. It is expected that this will eventually reduce the salinity of the main lake, while increasing the salinity of the diked impoundment to that of a concentrated brine

  10. Atlantis - The Sunken Indo-European Capital in the Black Sea

    Microsoft Academic Search

    Siegfried G. Schoppe; Christian M. Schoppe

    Until around 5500 BC the Black Sea was a (smaller) freshwater-lake. The breaking Bosporus sill led to a flood commonly referred to as Noah's Flood (Pitman\\/Ryan). Although heavily attacked, just recently this theory has gained support from new studies. We propose that Atlantis was an early Neolithic settlement at the former shoreline of that lake. With regard to the interactions

  11. Organochlorine pesticides residue in lakes of Khorezm, Uzbekistan

    USGS Publications Warehouse

    Rosen, Michael R.; Nishonov, Bakhriddin; Fayzieva, Dilorom; Saito, L.; Lamers, J.

    2009-01-01

    The Khorezm province in northwest Uzbekistan is a productive agricultural area within the Aral Sea Basin that produces cotton, rice and wheat. Various organochlorine pesticides were widely used for cotton production before Uzbekistan's independence in 1991. In Khorezm, small lakes have formed in natural depressions that receive inputs mostly from agricultural runoff. Samples from lake waters and sediments, as well as water from the Amu Darya River (which is the source of most of the lake water) have been analyzed to study variations in the concentrations of organochlorine pesticides residues during the year. Low concentrations of DDT, DDD, DDE, a-HCH and y-HCH compounds were found in water and sediment samples. The concentration of persistent organochlorine pesticides (DDT and HCH) in water and sediment is much lower than the maximum permissible concentrations that exist for water and soil. According to these preliminary results, the investigated lakes in Khorezm appear to be suitable for recreation or for aquaculture.

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

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

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

  13. Contrasting effects of managed opening regimes on water quality in two intermittently closed and open coastal lakes

    Microsoft Academic Search

    M. Schallenberg; S. T. Larned; S. Hayward; C. Arbuckle

    2010-01-01

    Intermittently closed and open lakes and lagoons (ICOLLs) are shallow barrier lakes which are intermittently connected to the sea and experience saline intrusions. Many ICOLLs are mechanically opened to prevent flooding of surrounding agricultural and urban land and to flush water of poor quality. In this study, the effects of modified opening regimes (frequency and duration of barrier openings and

  14. DISTRIBUTION AND ORIGIN OF DIATOMS IN THE BOTTOM SEDIMENTS OF THE SUEZ CANAL LAKES AND ADJACENT AREAS, EGYPT

    Microsoft Academic Search

    Abdelfattah A. Zalat

    2002-01-01

    The diatom assemblages in the bottom sediments of Timsah Lake and adjacent sites, including the Great Bitter Lake, the northern part of the Gulf of Suez and the Mediterranean Sea at the entrance of the northern canal, have been recovered and studied in detail. A total of 394 species and varieties belonging to 96 genera were identified. Of these, 263

  15. Human Effects on Varna-Beloslav Lake Complex and Detection of Long-Term Changes

    NASA Astrophysics Data System (ADS)

    Palazov, Atanas; Stanchev, Hristo; Stancheva, Margarita

    2013-04-01

    There are several larger lakes at the 412 km long Bulgarian Black Sea coastline, as each distinguishes with a specific hydrological regime and parameters. The deepest and the largest is the Varna Lake, located west from the Bay of Varna at the North Bulgarian coast. The lake is a firth formation at the river valley under a rising sea level during the Holocene, when it was divided from the sea by a large sandy spit. In 1900s with construction of Varna Port a navigational channel between Varna Lake and the sea was built, while in 1920s it was artificially connected to the inland Beloslav Lake by other navigational channel. Since the beginning of the past century the both lakes have been subject of many direct human impacts, such as: digging of three navigational channels; situating a number of ports with different functions; constantly performed dredging activities etc. The aim of this study was to trace the long-term changes to the lakes of Varna and Beloslav mostly related to human activities over a 100-year period. Two types of data were used: historical topographic map from 1910 in scale 1:200 000 and nautical maps in scale 1:10 000 from 1994. The data were processed and analysed with support of GIS and modelling in order to quantify the changes of areas and volumes of the lakes, as well as of the navigational channel between them. The findings from the study clearly reveal significant alterations of the two lakes that have been caused by increased anthropogenic impacts over the whole past century. Irreversible changes and modifications of the lakes features and coastal section around, as well as alterations of the areas and hydrological regime of the whole lake system were identified. In order to evaluate the anthropogenic impacts a coastline segmentation of the study area was performed as the lengths of natural and armoured coasts were determined. This in turn allowed finding the extent of technogenous occupation of the coast: 11107 m or about 24% from the total 46112 m long lakes coastline were armoured. Adding also two navigational channels having a total length of 8500 m, then the length of the technogenous coast has reached up to 42 %. In relation with required maintenance of the safe shipping depth and following permanent dredging works, it is suggests the examined Varna-Beloslav Lake system would experience continuative impacts and negative effects. At present, a new project for replacement of the Varna Port East to the northernmost part of the Varna Lake has been operating and this would suppose additional dredging activities leading to new changes of the coastline and bottom features of both lakes.

  16. Directly dated MIS 3 lake-level record from Lake Manix, Mojave Desert, California, USA

    USGS Publications Warehouse

    Reheis, Marith; Miller, David M.; McGeehin, John P.; Redwine, Joanna R.; Oviatt, Charles G.; Bright, Jordon E.

    2015-01-01

    An outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.

  17. Great Lakes Shoreline Geology

    NSDL National Science Digital Library

    This resource describes the shorelines of the Grate Lakes from the wetlands along the Lake Ontario shore, to the sand dunes along Lake Michigan, to the rocky shore of Lake Superior, which abounds in diversity. Students will discover that millions of years of glacial formation, wind, lava flows, and changing lake levels have sculpted a unique and ever changing shoreline. The first section describes the work of the glaciers while the second explains the formation, composition, and importance of beaches and continues to the third which describes sand dunes. The next section contains detailed information about the wetlands associated with the Great Lakes. The glaciated rocky shore of Isle Royale is the next topic and the site ends with a statement regarding human impact on the shoreline. Each section contains links to sites for more information.

  18. The Living Lakes

    NSDL National Science Digital Library

    Living Lakes Partnership, a nonprofit organization has a goal to "create and support a network within which local lake organizations can find critical kinds of assistance for promoting sustainable development in lake areas." Their award winning site highlights nearly twenty lakes around the world, describing their individual, watershed, and biological characteristics as well as the geologic and human history of the area. The Living With Lakes section discusses lake management and conservation issues dealing with agriculture and urban areas (such as pollution and habitat loss). Other links include a photo gallery, news and events section, discussion groups, and much more. Visitors will enjoy the rich content and visuals that make up this site and will find themselves exploring it for some time and learning along the way.

  19. Monitoring Changes in Water Resources Systems Using High Resolution Satellite Observations: Application to Lake Urmia

    NASA Astrophysics Data System (ADS)

    Norouzi, H.; AghaKouchak, A.; Madani, K.; Mirchi, A.; Farahmand, A.; Conway, C.

    2013-12-01

    Lake Urmia with its unique ecosystem in northwestern Iran is the second largest saltwater lake in the world. It is home of more than 300 species of birds, reptiles, and mammals with high salinity level of more than 300 g/l. In recent years, a significant water retreat has occurred in this lake. In this study, we tried to monitor the desiccation of the lake over more than four decades using remote sensing observations. Multi-spectral high-resolution LandSat images of the Lake Urmia region from 1972 to 2012 were acquired to derive the lake area. The composite maps of the lake were created, and a Bayesian Maximum Likelihood classification technique was used to classify land and water in the composite maps. The time series of the lake area reveals that it has shrunk by more than 40% in the past ten years. Moreover, water budget related components such as precipitation, soil moisture, and drought indices from remote sensing of the lake basin were utilized to investigate if droughts or climate change are the primary driving forces behind this phenomenon. These analyses show that the retreat of the lake is not related to droughts or global climate change as it has survived several drought events before year 2000. Similar analyses conducted on Lake Van located about 400 km west of Lake Urmia with very similar climate pattern revealed no significant areal change despite the lake's exposure to similar drought events. These results raise serious concern about the destructive role of unbridled development coupled with supply-oriented water management scheme driven by a classic upstream-downstream competition for water in the Lake Urmia region. There is an urgent need to investigate sustainable restoration initiatives for Lake Urmia in order to prevent an environmental disaster comparable to catastrophic death of Aral Sea.

  20. Lake Roosevelt Fisheries and Limnological Research : 1996 Annual Report.

    SciTech Connect

    Cichosz, Thomas A.; Underwood, Keith D.; Shields, John; Scholz, Allan; Tilson, Mary Beth

    1997-05-01

    The Lake Roosevelt Monitoring/Data Collection Program resulted from a merger between the Lake Roosevelt Monitoring Program and the Lake Roosevelt Data Collection Project. This project will model biological responses to reservoir operations, evaluate the effects of releasing hatchery origin kokanee salmon and rainbow trout on the fishery, and evaluate the success of various stocking strategies. In 1996, limnological, reservoir operation, zooplankton, and tagging data were collected. Mean reservoir elevation, storage volume and water retention time were reduced in 1996 relative to the last five years. In 1996, Lake Roosevelt reached a yearly low of 1,227 feet above mean sea level in April, a yearly high of 1,289 feet in July, and a mean yearly reservoir elevation of 1,271.4 feet. Mean monthly water retention times in Lake Roosevelt during 1996 ranged from 15.7 days in May to 49.2 days in October. Average zooplankton densities and biomass were lower in 1996 than 1995. Daphnia spp. and total zooplankton densities peaked during the summer, whereas minimum densities occurred during the spring. Approximately 300,000 kokanee salmon and 400,000 rainbow trout were released into Lake Roosevelt in 1996. The authors estimated 195,628 angler trips to Lake Roosevelt during 1996 with an economic value of $7,629,492.

  1. Sea level trends in South East Asian Seas (SEAS)

    NASA Astrophysics Data System (ADS)

    Strassburg, M. W.; Hamlington, B. D.; Leben, R. R.; Manurung, P.; Lumban Gaol, J.; Nababan, B.; Vignudelli, S.; Kim, K.-Y.

    2014-10-01

    Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

  2. To Brunswick Folsom Lake

    E-print Network

    ANGELS FROGTOWN MERIDIAN MINERALS RACETRACK STANISLAUS CALAVERAS ALPINE Markleeville EARLY INTAKE NEW Lake Mc Clure NEW MELONES PEORIA EXCHEQUER MERCED FALLS OAKHURST COARSEGOLD YANKE (NORTH FORK) LUNAR

  3. A Killer Lake

    NSDL National Science Digital Library

    Thomas Horvath

    2005-10-01

    In 1986, Lake Nyos, a volcanic lake in Cameroon, released a huge amount of carbon dioxide gas, killing over 1,700 people in the surrounding area. This case study, developed for use in a limnology or aquatic biology course, explores that event, introducing students to concepts relating to lake formation, thermal stratification, and dissolved gases. Students interpret graphs showing temperature, dissolved oxygen, pH, and conductivity measurements for the lake, and then synthesize these different types of limnological data to solve the problem.

  4. Texas' Natural Lake 

    E-print Network

    Wythe, Kathy

    2006-01-01

    . Unique because it is one of only 19 wetlands ?of unique importance? in the United States. Unique because of its bald cypress and tupelo trees that are Caddo?s Lake signature. This unique lake and its ecosystem, however, are being threatened... to distribute their seeds and dry spells that lower lake levels and allow seeds to germinate. Flooding in the past also helped sweep sediment from the lake and inhibited plant growth. Invasive aquatic plants, introduced by man, are choking off water bodies...

  5. Great Lakes Literacy Principles

    NASA Astrophysics Data System (ADS)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

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

  6. A Killer Lake

    NSDL National Science Digital Library

    Thomas Horvath

    2005-01-01

    In 1986, Lake Nyos, a volcanic lake located in Cameroon, Africa, released a huge amount of carbon dioxide gas, killing over 1,700 people and countless livestock and other animals in the area. This case, intended for use in a limnology or an aquatic biology course, explores that event, introducing students to concepts related to lake formation, thermal stratification, and dissolved gases. Students interpret graphs containing temperature, dissolved oxygen, pH, and conductivity data for the lake, and then synthesize these different types of limnological data to understand what happened.

  7. Grays Lake Ecosystem

    NSDL National Science Digital Library

    This case study looks at the marsh ecosystem of Grays Lake in southeast Idaho, and is hosted by the Northern Prairie Wildlife Research Center (NPWRC). Grays Lake has been the focus of numerous research studies to understand factors affecting breeding water birds, habitat management practices, populations, and geological factors. This report gives general information about the Grays Lake ecosystem, including climate, habitats, plant communities, wildlife, water, and geology. More specific details are given through flora and fauna lists, historical and cultural overviews, details about the Grays Lake National Wildlife Refuge, and research information on management of wetlands.

  8. Lake Tahoe Data Clearinghouse

    NSDL National Science Digital Library

    Hoong, Connie

    The Lake Tahoe Data Clearinghouse Web site is part of the US Geological Survey's Lake Tahoe Initiative. The agency's goal for the site is to facilitate the coordination of research, monitoring, and environmental-management activities in the Lake Tahoe Basin and to ensure the widest possible access to data and information resulting from such activities. Products available include Digital Elevation Models, Digital Orthophoto Quadrangles, Digital Line Graphs, Digital Raster Graphics, maps and soil information of the area, and much more. The downloads include clear descriptions and examples for those unsure of the particular data types, making their use a snap for researchers, professionals, or anyone interested in the Lake Tahoe region. [JAB

  9. Crater Lake revealed

    USGS Publications Warehouse

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

    2003-01-01

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

  10. Seismic investigation of Lake Issyk-Kul, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Gebhardt, C.; Naudts, L.; De Mol, L.; De Batist, M.

    2012-04-01

    Lake Issyk-Kul is located in an intramontane basin of the Tien Shan mountains in Kyrgyzstan, Central Asia. It has formed in a tectonically active region with W-E striking major thrust zones north and south of the lake. The lake's modern surface level is at 1607 m above sea level, maximum depth in the central basin of the lake is roughly 670 m, and the total water volume is around 1736 km3. The lake is elongated with 180 km in west-east and 60 km in south-north direction. With a surface area of 6232 km2, Lake Issyk-Kul is the second largest lake in the higher altitudes. The lake is characterized by two large delta areas at its western and eastern end, with the deltaic area being as wide as up to 60 km in the eastern and 40 km in the western part, and by steep slopes at the northern and southern shore with only a rather narrow shallower shelf area. The lake contains the sediments of the past up to several million years, and has been proposed as a future target for deep drilling within ICDP. Three seismic surveys by Russian and Belgian groups in 1982, 1997 and 2001 revealed a thick sediment infill in Lake Issyk-Kul. At both the western and the eastern end of the lake, large delta systems were formed by actual and previous inlets, namely the Tyup and Djyrgalan rivers in the eastern part of the lake (still active) and the Chu River at the western end (currently bypassing the lake). Large sub-aquatic channel systems are visible in the lake's bathymetry in the shallower part of the delta systems close to the river mouths. They were quite likely formed by these rivers during a former lake level lowstand. The delta system consists of stacked prograding delta lobes with a characteristic topset-foreset-bottomset configuration. These lobes together with sub-aerial terraces found at several spots around the lake witness lake level fluctuations of up to >400 m. The sediments in the central plain of Lake Issyk-Kul are mainly well-layered with many turbiditic sequences intercalated with pelagic background sedimentation. Sediments are slightly inclined towards south with increasing angles with depth, suggesting a halfgraben structure of the lake basin. Mass transport deposits such as debris flows are a common feature close to the steeper flanks around the central plain. The southern flank is characterized by many small terraces and several canyons that are related to the small inlets at the southern shore. The northern flank, however, shows a small, shallow shelf area of 25 to 30 m water depth. This area is characterized by glacial outwash sediments brought to the lake by small rivers that drain the large terminal moraines which are located north of the lake.

  11. Sea ice in the China Sea

    SciTech Connect

    Deng Shuqi [National Research Center for Marine Environmental Forecasts, Beijing (China)

    1993-12-31

    In every winter, sea ice occurring in Bohai Sea and the North Yellow Sea is the first-year ice which is going through generating, developing and thawing processes. Therefore, it is necessary to spatially and temporally describe ice period, freezing range, thickness variations and general motion of sea ice. The purpose of this paper is to provide initial general situation and features of sea ice for forecasting and researching sea ice.

  12. Sea Ice

    NASA Technical Reports Server (NTRS)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  13. Black Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

  14. Great Lakes: Great Gardening.

    ERIC Educational Resources Information Center

    New York Sea Grant Inst., Albany, NY.

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

  15. The Great Lakes.

    ERIC Educational Resources Information Center

    Seasons, 1987

    1987-01-01

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

  16. Lake Darling Comparison

    USGS Multimedia Gallery

    The photo on the left was taken on April 18, 1997 by a USGS Personnel, of the new gates at Lake Darling. The photo to the right was taken on June 13, 2011 by Nathan A. Stroh (USGS), of Lake Darling....

  17. Exploding Lakes in Cameroon

    USGS Multimedia Gallery

    In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. The gas burst in 1986 from the 200-m...

  18. Exploding Lakes in Cameroon

    USGS Multimedia Gallery

    In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows a pipe top and raft...

  19. Lake Wobegon Dice

    ERIC Educational Resources Information Center

    Moraleda, Jorge; Stork, David G.

    2012-01-01

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

  20. Archeology Around Yellowstone Lake

    NSDL National Science Digital Library

    Ann M. Johnson

    This 9-page PDF examines the importance of Yellowstone Lake to humans in prehistoric times. The shorelines around the lake have been eroding and exposing artifacts that remain hidden elsewhere in the Park. The archeological sites expose artifacts, mostly rock chips, which point to seasonal occupations such as stone procurement, tool manufacture and repair.

  1. Lessons from a Lake.

    ERIC Educational Resources Information Center

    Goethals, Susan

    1997-01-01

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

  2. Lake Michigan VANDERBURGH

    E-print Network

    Polly, David

    Lake Michigan LAKE JAY ALLEN KNOX VIGO WHITE CASS PIKE JASPER RUSH CLAY PARKE VERMILLION LAPORTE WHITLEY WASHINGTON JENNINGS TIPTON DELAWARE LAGRANGE HENDRICKS MONTGOMERY STEUBEN JOHNSON HOWARD HANCOCK 50 60 Kilometers Map of Indiana Counties Indiana Geological Survey · 611 North Walnut Grove Ave

  3. Great Lakes Beach Health

    USGS Multimedia Gallery

    As schools close for the year and summer weather beckons, many recreationalists head to the Great Lakes' public beaches. However, these coastal areas can become contaminated with disease-causing bacteria that threaten public health, disrupt water recreation, and pay a toll on the Great Lakes economi...

  4. Disiccation of the Aral Sea: A Water Management Disaster in the Soviet Union

    Microsoft Academic Search

    Philip P. Micklin

    1988-01-01

    The Aral Sea in the Soviet Union, formerly the world's fourth largest lake in area, is disappearing. Between 1960 and 1987, its level dropped nearly 13 meters, and its area decreased by 40 percent. Recession has resulted from reduced inflow caused primarily by withdrawals of water for irrigation. Severe environmental problems have resulted. The sea could dry to a residual

  5. Pesticides and PCBs in sediments and fish from the Salton Sea, California, USA

    Microsoft Academic Search

    Yelena Sapozhnikova; Ola Bawardi; Daniel Schlenk

    2004-01-01

    The Salton Sea, the largest manmade lake in California, is officially designated by the State of California as an agricultural drainage reservoir. The purpose of this study was to determine organochlorine and organophosphorous pesticides, as well as polychlorinated biphenyl (PCB) concentrations in sediments and fish tissues in the Salton Sea and evaluate the relative ecological risk of these compounds. Sediment

  6. The conservation ecology of the Podonidae from the Caspian and Aral seas

    Microsoft Academic Search

    N. V. Aladin

    1995-01-01

    Results of five expeditions to the Caspian Sea and 17 expeditions to the Aral Sea from 1976–1993 are presented. In these two large salt lakes, nine species of Podonidae were found, all of which were fairly euryhaline, except Caspievadne maximowitschi. Further, all of them were thermophilic, except Cornigerius bicornis, Caspievadne maximowitschi, and Pleopis polyphemoides. Sexual reproduction of the Podonidae in

  7. Characterization of land degradation along the receding Dead Sea coastal zone using airborne laser scanning

    E-print Network

    Marco, Shmuel "Shmulik"

    a consequence of increased usage of fresh water for irrigation and domestic needs (Yechieli et al., 1993 changes, quantification of their volumes, and documentation of the present state of the terrain regions is the shrinkage of water bodies (e.g., Lake Chad, the Aral Sea, and the Dead Sea) mainly

  8. Eastern lake survey: regional estimates of lake chemistry (journal version)

    Microsoft Academic Search

    D. H. Landers; W. S. Overton; R. A. Linthurst; D. F. Brakke

    1988-01-01

    The Eastern Lake Survey was conducted by the US EPA in the fall of 1984. Lakes were selected at random, based on a rigorous statistical design that permits estimates of the chemical and physical status of lake populations in specified regions of the survey. Complete chemical characterization was performed on water samples from each lake and a detailed-quality assurance and

  9. Polar lake circulation during ice break-up

    NASA Astrophysics Data System (ADS)

    Kirillin, Georgiy; Forrest, Alexander; Graves, Kelly; Laval, Bernard

    2014-05-01

    An extensive dataset on lake physical properties has been collected during the final stage of the ice-covered period in May-June 2013 in polar Lake Kilpisjärvi, Finland. The data reveal several important features of lake dynamics, which shed new light on the mechanism of ice cover break-up and ice melting in lakes and marginal seas. CTD transects with high spatial resolution showed up a 300m-wide upwelling zone in the center of the lake, driven by downslope converging flow of warm waters from open-water 'moat' along the lake shoreline. The resulting radial density gradient, balanced by the Coriolis force, created a lake-wide anti-cyclonically rotating gyre with a measured peak azimuthal velocity of 0.05 m/s. Appreciable marginal heating is driven in polar enclosed basins by high amount of solar radiation and by surface inflow of meltwater. Hence, quasi-geostrophic anticyclonic circulation is suggested to be a general feature of polar lakes, redistributing heat within a water body and potentially accelerating ice melting. In addition, high-resolution records of pressure, current velocities and water temperature revealed under-ice seiches with periods of 10 to 25 min. The ice breakup was associated with 10 times increase of seiche amplitudes under ice. The seiches decayed within 10-15 hours; during this short period, the previously ice-covered lake became ice-free. We suggest that seiche-driven vertical motions of the soft ice sheet contribute significantly to breaking and melting of seasonal ice in enclosed reservoirs.

  10. Database compilation: hydrology of Lake Tiberias (Jordan Valley)

    NASA Astrophysics Data System (ADS)

    Shentsis, Izabela; Rosenthal, Eliyahu; Magri, Fabien

    2014-05-01

    A long-term series of water balance data over the last 50 years is compiled to gain insights into the hydrology of the Lake Tiberias (LT) and surrounding aquifers. This database is used within the framework of a German-Israeli-Jordanian project (DFG Ma4450-2) in which numerical modeling is applied to study the mechanisms of deep fluid transport processes affecting the Tiberias basin. The LT is the largest natural freshwater lake in Israel. It is located in the northern part of the Dead Sea Rift. The behavior of the lake level is a result of the regional water balance caused mainly by interaction of two factors: (i) fluctuations of water inflow to the Lake, (ii) water exploitation in the adjacent aquifers and consumptions from the lake (pumping, diversion, etc). The replenishment of the lake occurs through drainage from surrounding mountains (Galilee, Golan Heights), entering the lake through the Jordan River and secondary streams (85%), direct precipitation (11%), fresh-saline springs discharging along the shoreline, divertion from Yarmouk river and internal springs and seeps. The major losses occur through the National Water Carrier (ca. 44%), evaporation (38%), local consumption and compensation to Jordan (in sum 12%). In spite of the increasing role of water exploitation, the natural inflow to the Lake remains the dominant factor of hydrological regime of the Tiberias Lake. Additionally, series of natural yield to the LT are reconstructed with precipitation data measured in the Tiberias basin (1922-2012). The earlier period (1877-1921) is evaluated considering long rainfall records at Beirut and Nazareth stations (Middle East Region). This data enables to use the LT yield as a complex indicator of the regional climate change. Though the data applies to the LT, this example shows the importance of large database. Their compilation defines the correct set-up of joint methodologies such as numerical modeling and hydrochemical analyses aimed to understand large-scale hydrological processes.

  11. Late quaternary sediments, minerals, and inferred geochemical history of Didwana Lake, Thar Desert, India

    USGS Publications Warehouse

    Wasson, R.J.; Smith, G.I.; Agrawal, D.P.

    1984-01-01

    Variations in clastic sediment texture, mineralogy of both evaporites formed at the surface and precipitates formed below the lake floor, and the relative chemical activities of the major dissolved components of the chemical precipitates, have allowed reconstruction of the history of salinity and water-level changes in Didwana Lake, Thar Desert, India. Hypersaline conditions prevailed at about the Last Glacial Maximum, with little evidence of clastic sediments entering the lake. Between ca. 13,000 and 6000 B.P. the lake level fluctuated widely, the lake alternately hypersaline and fresh, and clastic sediments were delivered to the lake at a low rate. Deep-water conditions occurred ca. 6000 B.P. and clastic influx increased abruptly. The water level dropped towards 4000 B.P. when the lake dried briefly. Since 4000 B.P. the lake has been ephemeral with a lowered rate of sedimentation and mildly saline conditions rather like those of today. This sequence of changes documented in the lake parallels changes in vegetation recorded in published pollen diagrams from both the Thar and the Arabian Sea. Correlation of the various lines of evidence suggests that the climate of the Last Glacial Maximum at Didwana was dry and windy with a weak monsson circulation. The monsson was re-established between ca. 13,000 and a little before 6000 B.P., and, when winter rainfall increased ca. 6000 B.P., the lake filled to its maximum depth. ?? 1984.

  12. Antarctic lakes (above and beneath the ice sheet): Analogues for Mars

    NASA Technical Reports Server (NTRS)

    Rice, J. W., Jr.

    1992-01-01

    The perennial ice covered lakes of the Antarctic are considered to be excellent analogues to lakes that once existed on Mars. Field studies of ice covered lakes, paleolakes, and polar beaches were conducted in the Bunger Hills Oasis, Eastern Antarctica. These studies are extended to the Dry Valleys, Western Antarctica, and the Arctic. Important distinctions were made between ice covered and non-ice covered bodies of water in terms of the geomorphic signatures produced. The most notable landforms produced by ice covered lakes are ice shoved ridges. These features form discrete segmented ramparts of boulders and sediments pushed up along the shores of lakes and/or seas. Sub-ice lakes have been discovered under the Antarctic ice sheet using radio echo sounding. These lakes occur in regions of low surface slope, low surface accumulations, and low ice velocity, and occupy bedrock hollows. The presence of sub-ice lakes below the Martian polar caps is possible. The discovery of the Antarctic sub-ice lakes raises possibilities concerning Martian lakes and exobiology.

  13. Dramatic Evaporation of the Aral Sea (with dates)

    NSDL National Science Digital Library

    Joycelyn Thomson

    2001-04-19

    DISAPPEARING WATER: THE ARAL SEA OVER TIME, FROM 1973 TO 2001 A time series is a powerful illustrative tool. Where in the case of Las Vegas we see the direct effects of people on the land, in the case of the Aral Sea, separating the countries of Kazakhstan and Uzbekistan, we see indirect, but no less dramatic effects on a different part of the world. The Aral Sea is actually not a sea at all. It is an immense lake, a body of fresh water, although that particular description of its contents might now be more a figure of speech than practical fact. In the last thirty years, more than sixty percent of the lake has disappeared. As youll see in the visualization, the change over time is dramatic. In the 1970s, farmers and state offices opened significant diversions from the rivers supplying water to the lake, sending millions of gallons to irrigate cotton fields and rice paddies. So voluminous were these irrigation sluices that concentrations of salts and minerals began to rise in the shrinking body of water. That change in chemistry has led to staggering alterations in the lakes ecology, causing precipitous drops in the Arals fish population. A secondary effect of this reduction in the Aral Seas overall size is the rapid exposure of the lake bed. Powerful winds that blow across this part of Asia routinely pick up and deposit tens of thousands of tons of now exposed soil every year. This has not only contributed to significant reduction in breathable air quality for nearby residents, but also appreciably affected crop yields due to those heavily salt laden particles falling on arable land. In the following sequence of images, we see a series of Landsat scenes taken several years apart. As the years pass, we see the profound reduction in overall area covered by the Aral, and a commensurate increase in land area as the floor of the sea now lies exposed.

  14. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

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

    2003-01-01

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

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

    USGS Publications Warehouse

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

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

  16. Aral Sea

    Atmospheric Science Data Center

    2013-04-16

    ... The retreating shoreline leaves the surface encrusted with salt and with agrochemicals brought in by the rivers. As the Sea's moderating ... Large Aral, and may be associated with windblown snow and/or salt particles carried aloft. The Multi-angle Imaging SpectroRadiometer ...

  17. Silver Lake Limnological Survey, 2004

    Microsoft Academic Search

    Joseph C. Makarewicz; Theodore W. Lewis; William Guenther

    2005-01-01

    During the spring, summer and fall of 2004, a limnological survey of Silver Lake was conducted. The purpose of the survey was to update the status of Silver Lake. Some of the questions being asked were as follows. Was the lake highly productive? Were the bottom layers of the lake devoid of oxygen? Was phosphorus being released from the sediments

  18. Lake Roosevelt Fisheries Monitoring Program; Lake Roosevelt Fisheries and Limnological Research; 1994 Annual Report.

    SciTech Connect

    Tilson, Mary Beth (Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA); Underwood, Keith D.; Shields, John (Spokane Tribe of Indians, Wellpinit, WA)

    1996-08-01

    This project began collecting biological data from Lake Roosevelt starting in 1991, with a long term goal of developing a computer model which accurately predicts biological responses to reservoir operations as part of the System Operation Review Program. In conjunction with the Lake Roosevelt Monitoring Project, this study collected limnological, reservoir operation, zooplankton, creel, net-pen rainbow trout and kokanee tagging data in 1994. Results obtained from current and past years data allow for the quantification of impacts to lake limnology, zooplankton, fish species and fisherman caused by reservoir drawdowns and low water retention times. in Lake Roosevelt, reservoir operations influence lake morphology as well as habitat availability for fish and their food. Lake elevations reached a yearly low of 1,263.90 feet above sea level in April and a yearly high of 1,288.50 feet in October. Lake Roosevelt experienced a peak in Daphnia spp. densities during July and August including the peak density of nearly 9,000 organisms per m{sup 3}. High densities of zooplankton were found in the lower end of the reservoir which supports the hypothesis that flushing of reservoir water increases downstream plankton densities and biomass as well as increasing entrainment of fishes. In 1994, a total of 26,975 net-pen rainbow trout were tagged at locations throughout the reservoir. Anglers fishing in Lake Roosevelt or below returned 448 tags, of which 399 tags were from fish tagged in 1994. Trends in tag returns continue to indicate that entrainment of Lake Roosevelt net-pen fish are influenced by water retention times and release times. Creel surveys of Rufus Woods were conducted over a six month period in 1993 and seven months in 1994 to estimate entrainment loss of tagged fish, however no tags were observed. Harvest estimates for the creel period were 46, 0 and 55 fish for rainbow trout, kokanee and walleye in 1993 and 384, 5 and 4,856 fish per year respectively in 1994.

  19. Introduction to the Great Lakes

    NSDL National Science Digital Library

    As part of The Great Lakes Information Network, The Education And Curriculum Homesite (TEACH) "focuses on advancing Great Lakes-related educational materials for the broad audience of educators and students in the Great Lakes region and beyond." The Introduction to the Great Lakes pages contain an overview of the watershed, including maps, photographs, and descriptions; other sections take a more detailed look at the five individual lakes. Additional links for further information are also provided -- such as Great Lake geography, history and culture, pollution, and more -- giving kids or anyone interested a well-designed introduction to the lakes.

  20. Modeling waves and circulation in Lake Pontchartrain, Louisiana

    USGS Publications Warehouse

    Signell, Richard P.; List, Jeffrey H.

    1997-01-01

    The U.S. Geological Survey is conducting a study of storm-driven sediment resuspension and transport in Lake Pontchartrain, Louisiana. Two critical processes related to sediment transport in the lake are (1) the resuspension of sediments due to wind-generated storm waves and (2) the movement of resuspended material by lake currents during storm wind events. The potential for sediment resuspension is being studied with the wave prediction model which simulates local generation of waves by wind and shallow-water effects on waves (refraction, shoaling, bottom friction, and breaking). Long-term wind measurements are then used to determine the regional "climate" of bottom orbital velocity (showing the spatial and temporal variability of wave-induced currents at the bottom). The circulation of the lake is being studied with a three-dimensional hydrodynamic model. Results of the modeling effort indicate that remote forcing due to water levels in Mississippi Sound dominate the circulation near the passes in the eastern end of the lake, while local wind forcing dominates water movement in the western end. During typical storms with winds from the north-northeast or the south-southeast, currents along the south coast near New Orleans generally transport material westward, while material in the central region moves against the wind. When periods of sustained winds are followed by a drop in coastal sea level, a large amount of suspended sediment can be flushed from the lake.

  1. Late Pleistocene-Holocene Climate Change Inferred from Fossil Fauna in the Marmara Sea, Turkey

    Microsoft Academic Search

    D. Gurung; C. M. McHugh; W. B. Ryan; L. Giosan; Y. Mart; N. Cagatau

    2006-01-01

    Paleoenvironmental changes that document the reconnection of the Marmara Sea to the world's oceans were investigated from sediment cores and high-resolution CHIRP subbottom profiles acquired by the R\\/V Mediterranean Explorer in 2005. The transition from a glacial fresh\\/brackish water lake to a sea took place after global sea-level reached the Dardanelles outlet sill depth of -85m. We surveyed the continental

  2. Yellowstone Lake Nanoarchaeota

    PubMed Central

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

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations. PMID:24062731

  3. Optical properties of the Dead Sea Emmanuel Boss,1

    E-print Network

    Boss, Emmanuel S.

    Optical properties of the Dead Sea Emmanuel Boss,1 Hezi Gildor,2 Wayne Slade,3 Leonid Sokoletsky,4, resulting in unique biogeochemistry and optical properties. In the spring of 2004 we conducted two days of physical and optical measurements in the lake. Because of the significant effect of dissolved salts

  4. Classification of lentic habitat for sea lamprey (Petromyzon marinus) larvae using a remote seabed classification device

    USGS Publications Warehouse

    Fodale, Michael F.; Bronte, Charles R.; Bergstedt, Roger A.; Cuddy, Douglas W.; Adams, Jean V.

    2003-01-01

    Lentic populations of larval sea lampreys (Petromyzon marinus) are suspected of being a major source of recruitment to parasitic stocks in some areas of the Great Lakes, and methods are needed to estimate habitat and population sizes. A deepwater electroshocker has been used to quantitatively assess larval sea lamprey populations in deepwater areas, however a method has not been developed to efficiently identify the most promising locations to sample in this environment. A remote seabed classification device (RoxAnna??) was used to identify soft substrates in a lentic area where sea lamprey larvae have been found in Batchawana Bay (Ontario) in eastern Lake Superior, and related those substrate types to larval distribution and occurrence. Presence of larvae was significantly related to substrate type, distance from the stream mouth, and slope of the lake bottom. Remote seabed classification would be a useful tool in the Sea Lamprey Control Program to identify the most promising locations to conduct larval surveys in lentic areas.

  5. Classification of lentic habitat for sea lamprey (Petromyzon marinus) larvae using a remote seabed classification device

    USGS Publications Warehouse

    Fodale, M.F.; Bronte, C.R.; Bergstedt, R.A.; Cuddy, D.W.; Adams, J.V.

    2003-01-01

    Lentic populations of larval sea lampreys (Petromyzon marinus) are suspected of being a major source of recruitment to parasitic stocks in some areas of the Great Lakes, and methods are needed to estimate habitat and population sizes. A deepwater electroshocker has been used to quantitatively assess larval sea lamprey populations in deepwater areas, however a method has not been developed to efficiently identify the most promising locations to sample in this environment. A remote seabed classification device (RoxAnn???) was used to identify soft substrates in a lentic area where sea lamprey larvae have been found in Batchawana Bay (Ontario) in eastern Lake Superior, and related those substrate types to larval distribution and occurrence. Presence of larvae was significantly related to substrate type, distance from the stream mouth, and slope of the lake bottom. Remote seabed classification would be a useful tool in the Sea Lamprey Control Program to identify the most promising locations to conduct larval surveys in lentic areas.

  6. Snow From Great Lakes Covers Buffalo

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On November 20, 2000, Buffalo, New York was blanketed by a late-autumn storm that left 25 inches of snow on the ground in a 24-hour period, most of it during the afternoon rush hour. Buffalo officials declared a state of emergency and New York National Guardsmen were called in to assist with clearing snow from roads. With the exception of essential vehicles or people retrieving stranded children, all driving was banned in the city. This SeaWiFS pass over the central United States and Canada depicts a source for all of the snow in Buffalo. Cold, dry Canadian air blowing toward the southeast picked up a lot of moisture from the relatively warm Great Lakes -- forming the clouds that lightened their loads over Buffalo. This image was acquired November 21, 2000, by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) flying aboard the Orbview-2 satellite. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  7. A note on the effects of an individual large rainfall event on saline Lake Alchichica, Mexico

    Microsoft Academic Search

    Javier Alcocer; Anatoliy E. Filonov

    2007-01-01

    The present study reports on perturbations of the water column by large rainfall at Lake Alchichica, a saline lake in Central\\u000a Mexico. Alchichica is located in the “Llanos de San Juan,” a high-altitude plateau with a minimum elevation of 2,300 m above\\u000a sea level. The climate is arid with annual precipitation less than 400 mm and annual evaporation of 500–600 mm. A single

  8. Lake Granbury and Lake Whitney Assessment Initiative 

    E-print Network

    Harris, B.L.; Roelke, Daniel; Grover, James; Brooks, Bryan

    2010-01-01

    A team of Texas AgriLife Research, Baylor University and University of Texas at Arlington researchers studied the biology and ecology of Prymnesium parvum (golden algae) in Texas lakes using a three-fold approach that involved system-wide monitoring...

  9. LAKE RESTORATION BY DILUTION: MOSES LAKE, WASHINGTON

    EPA Science Inventory

    Dilution water, low in macronutrients, was added to Moses Lake on three occasions in 1977 and once in 1978 during the spring-summer period. The addition resulted in reducing the annual average inflow concentration of phosphorus from about 130-140 micrograms/l to 100 micrograms/l....

  10. Factors of ecologic succession in oligotrophic fish communities of the Laurentian Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1972-01-01

    Oligotrophic fish communities of the Great Lakes have undergone successive disruptions since the mid-1800s. Major contributing factors have been intensive selective fisheries, extreme modification of the drainage, invasion of marine species, and progressive physical-chemical changes of the lake environments. Lake Ontario was the first to be affected as its basin was settled and industrialized earliest, and it was the first to be connected by canals to the mid-Atlantic where the alewife (Alosa pseudoharengus) and sea lamprey (Petromyzon marinus) which ultimately became established in the Great Lakes were abundant. Oligotrophic fish communities were successively disrupted in Lakes Erie, Huron, Michigan, and Superior as the affects of population growth, industrialization, and marine invaders spread upward in the Laurentian drainage. The degree and sequence of response of families of fish and species within families differed for each factor, but the sequence of change among families and species has been the same in response to each factor as it affected various lakes at different times. The ultimate result of the disruption of fish communities has been a reduction of productivity of oligotrophic species that ranges from extreme in Lake Ontario to moderate in Lake Superior, and which has reached a state of instability and rapid change in the upper three Great Lakes by the mid-1900s similar to the situation in Lake Ontario in the mid-1800s. Since oligotrophic species (primarily salmonines, coregonines, and deepwater cottids) are the only kinds of fish that fully occupied the entire volume of the deepwater Great Lakes (Ontario, Huron, Michigan, and Superior), the fish biomass of these lakes has been reduced as various species declined or disappeared. In Lake Erie, which is shallow, and in the shallow bays of the deep lakes, oligotrophic species were replaced by mesotrophic species, primarily percids, which have successively increased and declined. All oligotrophic species are greatly reduced or extinct in lakes Ontario and Erie, and are in various stages of decline in lakes Huron, Michigan, and Superior, from greatest to least, respectively. The percids appear to be near the end of their sequence of succession in lakes Erie, Ontario, and Huron (primarily Saginaw Bay) where only the yellow perch (Perca flavescens) remains abundant. The yellow perch appears to be on the brink of decline in Lake Erie, which has been more severely influenced by water quality change than the other lakes.

  11. Rearing of sea lamprey, Petromyzon marinus, embryos in distilled water

    USGS Publications Warehouse

    Piavis, George W.; Howell, John H.

    1969-01-01

    Most embryological studies of lampreys in the Great Lakes have been conducted with filtered water from Lake Huron. Although this water was entirely satisfactory for the earlier work, the present need for knowledge of the effects of various compounds on embryological development requires that the initial medium be sterile. The purpose of the present study was to determine whether sea lamprey embryos could be successfully reared in distilled water. Mature sea lampreys were collected from the Ocqueoc River, Presque Isle County, Michigan, and transferred to the Hammond Bay Biological Station where eggs were stripped and fertilized according to the method of Piavis. After activation was ascertained to be 90-100% complete, the embryos were washed 3-5 timesexperimentals with commercially obtained U.S.P. distilled water and controls with filtered Lake Huron water.

  12. Bathymetry of Crater Lake

    NSDL National Science Digital Library

    The bathymetry survey of Crater Lake by scientists from the USGS, University of New Hampshire's Center for Coastal and Ocean Mapping, and the National Park Service, began on July 28, 2000. This site houses the first images gained from the high-resolution multi-beam technology survey. Various digital data such as digital raster graphics and digital line graphs may be viewed as .jpeg and .gif images or downloaded as .zip files. Besides the bathymetric data, the site features information on the geology, ecology, and history of Crater Lake, and beautiful .gif images of the lake and surrounding areas.

  13. RESPONSE OF THE ROSS SEA ICE SHEET TO THE LAST DEGLACIATION: NEW EVIDENCE FROM TAYLOR VALLEY, ANTARCTICA

    Microsoft Academic Search

    M. L. Prentice; S. A. Arcone; J. L. Horsman; E. Medley; J. D. Toner; R. Sletten; K. Shoemaker

    2009-01-01

    We examined the origin of sediments derived from the Ross Sea Ice Sheet (RIS) in the McMurdo Sound region of Antarctica during the Last Glacial Maximum. It has been proposed that RIS sediments in Taylor Valley dating to the LGM and deglaciation were deposited in a deep Glacial Lake Washburn from a lake-ice conveyor connected to the RIS. The RIS

  14. The storage and release of water from a large glacier-dammed lake; Russell Lake near Yakutat, Alaska, 1986

    USGS Publications Warehouse

    Seitz, H.R.; Thomas, D.S.; Tomlinson, Bud

    1986-01-01

    In May 1986, the entrance to Russell Fiord, Alaska, was blocked by the advancing Hubbard Glacier, forming a 34-mile long ice-dammed lake. Runoff to the lake, mainly runoff from melting snow and glacier ice, filled the lake to an elevation of 83 feet above sea level by October 8, when the ice dam failed. The lake level rose at an average rate of 0.6 ft/day, and average daily inflow to the lake was calculated to be 16,500 cu ft/sec. After failure of the ice dam, the water level fell to the former high tide level of Russell Fiord within 24 hours. Average discharge through the breach in the ice dam during a 4-hr period of maximum water level decline is estimated to have been 3.8 million cu ft/sec. The formation and breakout of the lake is expected to be repeated as the Hubbard Glacier continues to advance, though the timing of the phenomenon cannot be predicted with certainty. (USGS)

  15. Sea Ice

    NSDL National Science Digital Library

    In this resource, students will discover that there are notable differences between sea ice and fresh-water ice, such as density. In on segment, students learn that the first sign of freezing on the sea is an oily appearance of the water caused by the formation of needle-like crystals. The site explains the relationship between growth and the rate at which heat flows from the water and that the ice pack can alter its shape and dimension due to the movement of winds, currents, thermal expansion, and contraction of the ice. Types of ice described here include new ice, nilas, young ice, first-year ice, and old ice while the forms of ice covered include pancake ice, brash ice, ice cake, floe, and fast ice. The site also explains the meteorological and oceanographic factors that control the amount and movement of ice.

  16. Sea World

    NSDL National Science Digital Library

    Excellent resource for information and teaching activities on marine life, designed primarily for elementary level. Teachers can sign up for a monthly e-newsletter (or access archived newsletters) filled with classroom activities, current information, and special links. Also features a searchable database of Sea World education materials and information on camps, marine science careers, and Shamu TV, an award-winning series broadcast around the country via satellite and cable.

  17. TEACH Great Lakes

    NSDL National Science Digital Library

    1969-12-31

    The TEACH Great Lakes Web site is provided by the Great Lakes Information Network (last mentioned in the September 15, 1995 Scout Report). The site features online lessons specific to Great Lakes subjects such as the environment, geography, and pollution. Students can begin with the Introduction to the Great Lakes module and then move on to learn about water levels, shoreline geology, water pollution, and even explore the history and culture or careers and business areas as well. Geared for elementary through high school students, the activities present easily read material along with good photographs and other interesting graphics. Overall, the site provides good information on interesting topics with which students will enjoy becoming familiar as part of their science related curriculum.

  18. Is Lake Tahoe Terminal?

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Lake Tahoe, an iconic ultra-oligotrophic lake in the central Sierra Nevada, has been studied intensively since 1968, with the goal of understanding and ultimately controlling its eutrophication and loss of clarity. Research on the lake has included a) periodic profiles of primary productivity, nutrients, temperature, and plankton; b) Secchi depth; c) nutrient limitation experiments; d) analysis of sediment cores; e) radiocarbon dating of underwater in-place tree stumps; g) analysis of long-term temperature trends. Work in its watershed has included a) monitoring of stream discharge, sediment and nutrients at up to 20 stream gaging stations; b) monitoring of urban runoff water quality at selected sites; c) development of a GIS data base, including soils, vegetation, and land use. Based on these studies, we know that a) primary productivity in the lake is limited by phosphorus, and continues to increase; b) the loss of clarity continues, but at a declining rate; c) the lake has been warming since 1970, and its resistance to deep mixing is increasing; d) historically the lake level drops below the outlet elevation about one year in seven; e) 6300 to 4300 yrs BP lake level was below the present outlet elevation long enough for large trees to grow; f) the date of the peak snowmelt runoff is shifting toward earlier dates; g) after accounting for annual runoff, loads of nutrients and suspended sediment have declined significantly in some basin streams since 1980. Downscaled outputs from GCM climatic models have recently been used to drive hydrologic models and a lake clarity model, projecting future trends in the lake and watersheds. Results show a) the temperature and thermal stability will likely continue to increase, with deep mixing shutting down in the latter half of this century; b) the lake may drop below the outlet for an extended period beginning about 2085; c) the annual snowpack will continue to decline, with earlier snowmelt and shift from snowfall to rain; d) the climatic water deficit will increase, especially at high elevations that will be most affected by the loss of snow, with likely consequences for existing vegetation and fire frequency. Hydrologically, Lake Tahoe is intermittently terminal; in a medical sense it is not yet terminal, but its condition—especially its valued clarity and deep blue color--is serious.

  19. Exotic species in large lakes of the world

    Microsoft Academic Search

    S. R Hall; E. L Mills

    2000-01-01

    Many of the large lakes of the world have been exposed to the introduction of exotic species. We have reviewed here the introduction of aquatic species in 18 large lakes on five continents (Laurentian Great Lakes, African Great Lakes, several Canadian lakes, Lake Titicaca, Lake Baikal, Lake Ladoga, Gatun Lake, and Lake Biwa). We found that human activities, social preferences,

  20. Evidence for lack of homing by sea lampreys

    USGS Publications Warehouse

    Bergstedt, Roger A.; Seelye, James G.

    1995-01-01

    Recently metamorphosed sea lampreys Petromyzon marinus were captured in the Devil River, a tributary to Lake Huron, during summer and autumn 1990. They were tagged with a coded wire tag and returned to the river to continue their migration to Lake Huron to begin the parasitic (juvenile) phase of their life. During the spawning run in spring 1992 when the tagged animals were expected to mature and return to spawn, sea lampreys were trapped in nine tributaries to Lake Huron, including the Devil River; 47,946 animals were examined for coded wire tags, and 41 tagged animals were recovered. None of the 45 mature sea lampreys captured in the Devil River in 1992 were tagged, a proportion (0%) significantly lower than the proportion of the recently metamorphosed sea lampreys tagged in 1990. The distribution of tag recoveries among streams lakewide, however, was proportional to catch. Tagged sea lampreys did not appear to home, but instead seemed to select spawning streams through innate attraction to other sensory cues.

  1. Lake Baikal Homepage

    NSDL National Science Digital Library

    One of the deepest and most ancient lakes in the world, Lake Baikal is situated in the south of Eastern Siberia. Its age and complicated evolutionary history make it home to a wide variety of plants and animals. This site describes ecological problems, climatic conditions, geology, and cultural aspects of the region, and includes detailed maps and photographs. Portions of the site are translated into French and German.

  2. Lake Superior, Duluth, MN

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  3. A Killer Lake

    NSDL National Science Digital Library

    Thomas Horvath

    These are the teaching notes for a case study in which students are presented with data on a particular lake that they must synthesize in order to determine the cause of an event that occurred in 1986 in Cameroon, Africa. The case centers on Cameroon's Lake Nyos, a volcanic lake which released a large quantity of carbon dioxide gas, killing over 1700 people, livestock, and wildlife in the area. The case can be used in a limnology or an aquatic biology course and was intended to introduce and reinforce the concepts of thermal stratification and use students' curiosity about this event to get them to think about how layers of water develop. The case could also be extended to cover or review other concepts such as lake formation (in this case, volcanism as a lake-forming process) or gas solution (in this case, carbon dioxide solution). The case could also be used throughout a limnology course because it deals with many aspects of the subject: lake origins, thermal stratification, gases, water movements, and applied limnology (remediation of problems). Instructors can introduce the case early in a course and refer back to it when each new topic comes up. The case also allows students to synthesize different types of limnological data to solve a serious problem.

  4. Lake bottom magnetotellurics

    NASA Astrophysics Data System (ADS)

    Schultz, Adam; Booker, John; Larsen, Jim

    1987-09-01

    The study of the electrical conductivity structure of the lower crust and the upper mantle and midmantle promises to place important constraints on the thermobaric and compositional state of the earth's interior. Such work, particularly for depths above approximately 400 km, is best attempted by magnetotelluric sounding, an effort frustrated by the almost complete absence of stable long-period electric field measurements. In this paper, we propose that proven techniques developed for seafloor magnetotellurics be applied also to deep freshwater lakes. The establishment of such long-period electric and magnetic observatories in the thermally stable, low-noise lake bottom environment will yield new insights on the deep electrical structure beneath the continents. A lake bottom long-span electric field array was deployed in a deep freshwater lake adjacent to Seattle, Washington. A vector flux gate magnetometer was buried on the shore of the lake, and magnetotelluric data of high quality were collected. The analysis of the data described in this work clearly demonstrates the feasibility of establishing such lake bottom continental magnetotelluric observatories. Inversion of the data provides a view of structure beneath the site consistent with regional seismic and tectonic models.

  5. Clear Lake Annotated Bibliography October 2, 2009

    E-print Network

    Thompson, Lisa C.

    : Newspaper Article Record Number: 256 Year: 1859 Title: Another California Curiosity-Borax Lake Newspaper Curiosity-Borax Lake Abstract: need abstract Notes: clear lake; pollution; html ONLINE -borax lake -sulphur

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

    USGS Publications Warehouse

    Edsall, Thomas A.; Kennedy, Gregory W.

    1995-01-01

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

  7. Microbial water quality of recreational lakes near Tbilisi, Georgia.

    PubMed

    Jaiani, Ekaterine; Kokashvili, Tamar; Mitaishvili, Nino; Elbakidze, Tinantin; Janelidze, Nino; Lashkhi, Nino; Kalandadze, Rusudan; Mikashavidze, Eteri; Natroshvili, Gulnara; Whitehouse, Chris A; Huq, Anwar; Tediashvili, Marina

    2013-06-01

    Microbial safety of recreational water is one of the major human public health issues in developing countries. Three water bodies, the Tbilisi Sea, Kumisi and Lisi lakes, in the South Caucasus region near Tbilisi, Georgia, were monitored in 2006-2009 to determine microbiological quality using standard methods. Microbial pollution indicators were determined in parallel with phytoplankton abundance and measurement of a number of physical-chemical parameters. Kumisi Lake, a brackish water body in an active agricultural area, appeared to be the most polluted, whereas the Tbilisi Sea, a freshwater reservoir was the least polluted. High values for fecal indicators in all three lakes in summer and early autumn were revealed. In our study, total enterococci counts (TEC) appeared to be a better indicator than either fecal or total coliform counts for the evaluation of fresh and brackish microbial water quality. We found significant correlation between total Vibrio counts and TEC for all three water bodies. Prevalence of somatic coliphages and V. cholerae-specific phages as additional water pollution indicator significantly correlated with abundance of the host bacteria. Particular phytoplankton groups in the lakes responded to the changes of fecal indicators; however, no correlation was observed between dominant zooplankton taxonomic groups and microbial parameters. PMID:23708580

  8. Dynamics of the Lake Michigan food web, 1970-2000

    USGS Publications Warehouse

    Madenjian, Charles P.; Fahnenstiel, Gary L.; Johengen, Thomas H.; Nalepa, Thomas F.; Vanderploeg, Henry A.; Fleischer, Guy W.; Schneeberger, Philip J.; Benjamin, Darren M.; Smith, Emily B.; Bence, James R.; Rutherford, Edward S.; Lavis, Dennis S.; Robertson, Dale M.; Jude, David J.; Ebener, Mark P.

    2002-01-01

    Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey (Petromyzon marinus) and alewife (Alosa pseudoharengus) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish (Coregonus clupeaformis) and burbot (Lota lota) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin (Myoxocephalus thompsoni), yellow perch (Perca flavescens), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia, oligochaetes, and sphaeriids, during the 1980s in nearshore waters (50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel (Dreissena polymorpha) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.

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

    USGS Publications Warehouse

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

    1991-01-01

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

  10. COSEE Great Lakes Lake Superior Exploration Workshop

    NSDL National Science Digital Library

    Teachers of grades 4-10 or informal settings and scientists from universities, federal agencies, state agencies, and not-for-profit organizations are invited to take part in innovative and cutting edge science education. Participants will experience the Lake Superior ecosystem firsthand with experts through: field and classroom activities, classroom activity idea sharing, learning how to use cutting edge research, data, and technology with their students, and making peer connections.

  11. Gravity field over the Sea of Galilee: Evidence for a composite basin along a transform fault

    USGS Publications Warehouse

    Ben-Avraham, Z.; ten Brink, U.; Bell, R.; Reznikov, M.

    1996-01-01

    The Sea of Galilee (Lake Kinneret) is located at the northern portion of the Kinneret-Bet Shean basin, in the northern Dead Sea transform. Three hundred kilometers of continuous marine gravity data were collected in the lake and integrated with land gravity data to a distance of more than 20 km around the lake. Analyses of the gravity data resulted in a free-air anomaly map, a variable density Bouguer anomaly map, and a horizontal first derivative map of the Bouguer anomaly. These maps, together with gravity models of profiles across the lake and the area south of it, were used to infer the geometry of the basins in this region and the main faults of the transform system. The Sea of Galilee can be divided into two units. The southern half is a pull-apart that extends to the Kinarot Valley, south of the lake, whereas the northern half was formed by rotational opening and transverse normal faults. The deepest part of the basinal area is located well south of the deepest bathymetric depression. This implies that the northeastern part of the lake, where the bathymetry is the deepest, is a young feature that is actively subsiding now. The pull-apart basin is almost symmetrical in the southern part of the lake and in the Kinarot Valley south of the lake. This suggests that the basin here is bounded by strike-slip faults on both sides. The eastern boundary fault extends to the northern part of the lake, while the western fault does not cross the northern part. The main factor controlling the structural complexity of this area is the interaction of the Dead Sea transform with a subperpendicular fault system and rotated blocks.

  12. Lake Investigation: Determining Lake Type and Health Using the Internet

    NSDL National Science Digital Library

    Seth Webster

    This activity is an on-line research activity in which students research different Minnesota lakes and determine their physical characteristics, chemical characteristics, and the overall health of the lake.

  13. Glacial Lake Musselshell: Late Wisconsin slackwater on the Laurentide ice margin in central Montana, USA

    USGS Publications Warehouse

    Davis, N.K.; Locke, W. W., III; Pierce, K.L.; Finkel, R.C.

    2006-01-01

    Cosmogenic surface exposure ages of glacial boulders deposited in ice-marginal Lake Musselshell suggest that the lake existed between 20 and 11.5 ka during the Late Wisconsin glacial stage (MIS 2), rather than during the Late Illinoian stage (MIS 6) as traditionally thought. The altitude of the highest ice-rafted boulders and the lowest passes on the modern divide indicate that glacial lake water in the Musselshell River basin reached at least 920-930 m above sea level and generally remained below 940 m. Exposures of rhythmically bedded silt and fine sand indicate that Lake Musselshell is best described as a slackwater system, in which the ice-dammed Missouri and Musselshell Rivers rose and fell progressively throughout the existence of the lake rather than establishing a lake surface with a stable elevation. The absence of varves, deltas and shorelines also implies an unstable lake. The changing volume of the lake implies that the Laurentide ice sheet was not stable at its southernmost position in central Montana. A continuous sequence of alternating slackwater lake sediment and lacustrine sheetflood deposits indicates that at least three advances of the Laurentide ice sheet occurred in central Montana between 20 and 11.5 ka. Between each advance, it appears that Lake Musselshell drained to the north and formed two outlet channels that are now occupied by extremely underfit streams. A third outlet formed when the water in Lake Musselshell fully breached the Larb Hills, resulting in the final drainage of the lake. The channel through the Larb Hills is now occupied by the Missouri River, implying that the present Missouri River channel east of the Musselshell River confluence was not created until the Late Wisconsin, possibly as late as 11.5 ka. ?? 2005 Elsevier B.V. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  15. Assessment Of Bacterial Sources Impacting Lake Waco And Belton Lake 

    E-print Network

    Giovanni, G.

    2006-01-01

    in Lake Waco and Belton Lake watersheds. Potential fecal sources were identified through a sanitary survey conducted by Parsons. Between October 2003 and October 2004, a total of 994 fecal samples were collected from known sources. Municipal...SR-2006-07 Assessment Of Bacterial Sources Impacting Lake Waco And Belton Lake Prepared for: TEXAS FARM BUREAU Prepared by: PARSONS TEXAS A&M UNIVERSITY AGRICULTURAL RESEARCH & EXTENSION CENTER AT EL PASO, TEXAS AGRICULTURAL EXPERIMENT STATION...

  16. Contaminant trends in lake trout ( Salvelinus namaycush ) from the Upper Great Lakes

    Microsoft Academic Search

    David S. DeVault; Wayne A. Willford; Robert J. Hesselberg; David A. Nortrupt; Eric G. S. Rundberg; Alwan K. Alwan; Cecilia Bautista

    1986-01-01

    Contaminant body burdens in lake trout (Salvelinus namaycush) from the Upper Great Lakes have been monitored since 1970 on Lake Michigan and since 1977 and 1978 on Lakes Superior and Huron by United States Environmental Protection Agency (USEPA), Great Lakes National Program Office and U.S. Fish and Wildlife Service (USFWS), Great Lakes Fishery Laboratory. Analysis of the Lake Michigan data

  17. New Bathymetry for Lake Erie and Lake Sinclair

    NSDL National Science Digital Library

    Online previews of posters and data of the lake floor topography of Lakes Erie and Sinclair are available from the National Geophysical Data Center. Here users can view full-color .jpeg images of the bathymetry, meter-scale lake floor topography, and partial samples of gridded and vector data.

  18. EASTERN LAKE SURVEY: REGIONAL ESTIMATES OF LAKE CHEMISTRY (JOURNAL VERSION)

    EPA Science Inventory

    The Eastern Lake Survey was conducted by the US EPA in the fall of 1984. Lakes were selected at random, based on a rigorous statistical design that permits estimates of the chemical and physical status of lake populations in specified regions of the survey. Complete chemical char...

  19. Lake-level variation in the Lahontan basin for the past 50,000 years

    USGS Publications Warehouse

    Benson, L.V.; Thompson, R.S.

    1987-01-01

    Selected radiocarbon data on surficial materials from the Lahontan basin, Nevada and California, provide a chronology of lake-level variation for the past 50,000 yr. A moderate-sized lake connected three western Lahontan subbasins (the Smoke Creek-Black Rock Desert subbasin, the Pyramid Lake subbasin, and the Winnemucca Dry Lake subbasin) from about 45,000 to 16,500 yr B.P. Between 50,000 and 45,000 yr B.P., Walker Lake rose to its sill level in Adrian Valley and spilled to the Carson Desert subbasin. By 20,000 yr B.P., lake level in the western Lahontan subbasins had risen to about 1265 m above sea level, where it remained for 3500 yr. By 16,000 yr B.P., lake level in the western Lahontan subbasins had fallen to 1240 m. This recession appears synchronous with a desiccation of Walker Lake; however, whether the Walker Lake desiccation resulted from climate change or from diversion of the Walker River is not known. From about 15,000 to 13,500 yr B.P., lake level rapidly rose, so that Lake Lahontan was a single body of water by 14,000 yr B.P. The lake appears to have reached a maximum highstand altitude of 1330 m by 13,500 yr B.P., a condition that persisted until about 12,500 yr B.P., at which time lake level fell ???100 m. No data exist that indicate the level of lakes in the various subbasins between 12,000 and 10,000 yr B.P. During the Holocene, the Lahontan basin was the site of shallow lakes, with many subbasins being the site of one or more periods of desiccation. The shape of the lake-level curve for the three western subbasins indicates that past changes in the hydrologic balance (and hence climate) of the Lahontan basin were large in magnitude and took place in a rapid step-like manner. The rapid changes in lake level are hypothesized to have resulted from changes in the mean position of the jet stream, as it was forced north or south by the changing size and shape of the continental ice sheet. ?? 1987.

  20. Sea-level and environmental changes since the last interglacial in the Gulf of Carpentaria, Australia: an overview

    USGS Publications Warehouse

    Chivas, Allan R.; Garc??a, Adriana; van der Kaars, Sander; Couapel, Martine; Holt, Sabine; Reeves, Jessica M.; Wheeler, David J.; Switzer, Adam D.; Murray-Wallace, Colin V.; Banerjee, Debabrata; Price, David M.; Wang, Sue X.; Pearson, Grant; Edgar, N. Terry; Beaufort, Luc; de Deckker, Patrick; Lawson, Ewan; Cecil, C. Blaine

    2001-01-01

    The Gulf of Carpentaria is an epicontinental sea (maximum depth 70 m) between Australia and New Guinea, bordered to the east by Torres Strait (currently 12 m deep) and to the west by the Arafura Sill (53 m below present sea level). Throughout the Quaternary, during times of low sea-level, the Gulf was separated from the open waters of the Indian and Pacific Oceans, forming Lake Carpentaria, an isolation basin, perched above contemporaneous sea-level with outlet channels to the Arafura Sea. A preliminary interpretation is presented of the palaeoenvironments recorded in six sediment cores collected by the IMAGES program in the Gulf of Carpentaria. The longest core (approx. 15 m) spans the past 130 ka and includes a record of sea-level/lake-level changes, with particular complexity between 80 and 40 ka when sea-level repeatedly breached and withdrew from Gulf/Lake Carpentaria. Evidence from biotic remains (foraminifers, ostracods, pollen), sedimentology and geochemistry clearly identifies a final marine transgression at about 9.7 ka (radiocarbon years). Before this transgression, Lake Carpentaria was surrounded by grassland, was near full, and may have had a surface area approaching 600 km×300 km and a depth of about 15 m. The earlier rise in sea-level which accompanied the Marine Isotopic Stage 6/5 transgression at about 130 ka is constrained by sedimentological and biotic evidence and dated by optical- and thermoluminescence and amino acid racemisation methods.

  1. GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY

    E-print Network

    #12;GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY ANNUAL REPORT FY 1977 October 1977 Eugene J Research Laboratories Great Lakes Environmental Research Laboratory 2300 Washtenaw Avenue Ann Arbor, Michigan 48104. #12;NOTICE The NOAA Environmental Research Laboratories do not approve, recommend

  2. Modeling the circulation of the Dead Sea

    NASA Astrophysics Data System (ADS)

    Brenner, Steve; Lensky, Nadav; Gertman, Isaac

    2015-04-01

    The Dead Sea is a hypersaline, terminal lake located at the lowest point on the land surface of the Earth. Its current level is more than 429 m below MSL, and due to a negative water balance (mainly anthropogenic), the lake level has been dropping at an average rate of more than 1 m/yr for more than 30 years. The mean salinity has also been steadily increasing and today is close to 280 psu. The region of the Dead Sea is a unique landscape that has important historical, cultural, and economic value and therefore such an extreme change of the lake has significant environmental and economic consequences. In recent years there has been a notable increase in observing and monitoring of the lake through continuous measurements from several fixed buoys as well as during quasi-regular cruises. In order to complement the measurements and improve our understanding of the dynamics of this unique lake a three dimensional circulation model is being developed. Previous modeling efforts were limited mainly to a one dimensional column model which was coupled to a comprehensive physio-chemical model and used for long term multi-decadal simulations. In this study the focus is on understanding the dynamical processes that control the lake-wide circulation on time scales ranging from days to seasons. The first step was to replace the equation of state with an equation appropriate for the hypersaline conditions, in addition to some minor tuning of the turbulence closure scheme. Results will be presented from preliminary simulations of the wind driven circulation in various seasons. A case study of a recent unusual winter flooding event, during which the lake level rose by more than 20 cm over a two month period, will also be presented. The model successfully simulated the observed transition from holomictic to meromictic conditions and epilimnion dilution during this event, as well as the restoration of holomictic conditions when the level started to drop again. The relationship between the water balance and stability of the epilimnion will also be discussed.

  3. Mono Lake Excursion Reviewed

    NASA Astrophysics Data System (ADS)

    Liddicoat, J. C.; Coe, R. S.

    2007-05-01

    The Mono Lake Excursion as recorded in the Mono Basin, CA, has an older part that is about negative 30 degrees inclination and about 300 degrees declination during low relative field intensity. Those paleomagnetic directions are closely followed by greater than 80 degrees positive inclination and east declination of about 100 degrees during higher relative field intensity. A path of the Virtual Geomagnetic Poles (VGPs) for the older part followed from old to young forms a large clockwise loop that reaches 35 degrees N latitude and is centered at about 35 degrees E longitude. That loop is followed by a smaller one that is counterclockwise and centered at about 70 degrees N latitude and 270 degrees E longitude (Denham & Cox, 1971; Denham, 1974; Liddicoat & Coe, 1979). The Mono Lake Excursion outside the Mono Basin in western North America is recorded as nearly the full excursion at Summer Lake, OR (Negrini et al., 1984), and as the younger portion of steep positive inclination/east declination in the Lahontan Basin, NV. The overall relative field intensity during the Mono Lake Excursion in the Lahontan Basin mirrors very closely the relative field intensity in the Mono Basin (Liddicoat, 1992, 1996; Coe & Liddicoat, 1994). Using 14C and 40Ar/39Ar dates (Kent et al., 2002) and paleoclimate and relative paleointensity records (Zimmerman et al., 2006) for the Mono Lake Excursion in the Mono Basin, it has been proposed that the Mono Lake Excursion might be older than originally believed and instead be the Laschamp Excursion at about 40,000 yrs B.P. (Guillou et al., 2004). On the contrary, we favor a younger age for the Mono Lake Excursion, about 32,000 yrs B.P., using the relative paleointensity in the Mono Basin and Lahontan Basin and 14C dates from the Lahontan Basin (Benson et al., 2002). The age of about 32,000 yrs B.P. is also in accord with the age (32,000- 34,000 yrs B.P.) reported by Channell (2006) for the Mono Lake Excursion at ODP Site 919 in the Irminger Basin in the North Atlantic Ocean, which contains as well an excursion lower in the core at about 40,000 yrs B.P. that he identifies as the Laschamp Excursion. The paths of VGPs for the Irminger Basin and the younger half of the Mono Lake Excursion in the Mono Basin are similar in that they are counterclockwise loops and nearly adjacent to each other, and quite different from the VGP path for the Laschamp Excursion.

  4. Crater Lake Data Clearinghouse

    NSDL National Science Digital Library

    This portal provides access to an extensive collection of resources on Oregon's Crater Lake, featuring sections on digital data, science, and general interest. The digital data section features links to a variety of imagery and datasets such as bathymetry, Digital Raster Graphics (DRG), Digital Line Graphs (DLG), Digital Elevation Models (DEM) of topography and other cartographic information; Digital Orthophoto Quadrangles (DOQ), orthoscopically corrected aerial photos in which ground features are displayed in their true positions; and a link to ArcView coverages of federal lands and counties in Oregon. The science section contains information on the formation and geologic history of the lake, lake ecology, physiographic information (lake depth, diameter, surface area, etc.), satellite imagery, and a glossary of volcano terminology and landform features pertinent to the lake. The general interest section contains an image gallery, information on cultural history, links to information on plants and wildlife, a location map and directions, a frequently-asked-questions feature, and links to external sites with additional information.

  5. Chemical characteristics of Lake Ontario

    USGS Publications Warehouse

    Allen, Herbert E.

    1969-01-01

    Records are presented of Na+, K+, Ca++, SiO2, pH, alkalinity, O2, and specific conductance at 106 stations in Lake Ontario. These data are compared for east-west and surface-subsurface variations. Water quality in Lake Ontario is similar to that in Lake Erie with the exception of dissolved oxygen. The open waters of Lake Ontario had no areas of serious oxygen depletions.

  6. Living with the Great Lakes

    NSDL National Science Digital Library

    Patricia Videtich

    This site was developed to assist students and educators with learning about the Great Lakes. The topics discussed include, grain size, langmuir circulation, longshore current, beach drift, river plumes, lake stratification, and waves. Lesson plans can be found on the following subjects: lake levels, sediments, stream flow, and water quality. Also included is a virtual flight along the Eastern Lake Michigan Shoreline which includes topo maps, 3D maps, and photos. A directory of related links is also available.

  7. Phytoplankton productivity in findley lake

    Microsoft Academic Search

    George R. Hendrey; Eugene B. Welch

    1974-01-01

    Findley Lake is a dimictic, oligotrophic, subalpine lake located in the western Cascade Mountains, Washington. The lake is\\u000a snow covered for most of the year so that the growing season was 3.5 months in 1971 and 4.5 months in 1972. Rapid melt of\\u000a the lake's snow cover in summer allowed the sudden development of a phytoplankton productivity maximum (as measured

  8. 75 FR 22620 - Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife Refuges...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-29

    ...Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife...Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife...Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake Refuges...

  9. The Geochemistry and Hydrography of Lake Tanganyika

    NASA Astrophysics Data System (ADS)

    Craig, H.

    2001-12-01

    John Edmond was a key member of the scientific group that participated in the two SIO expeditions on Lake Tanganyika, involved in both the water sampling on the lake and the operations in the potable chemical laboratory used ashore. Much of his data on the nutrient chemistry of the lake has been published in summary form (Limnol.Oceanog.1993). The present paper, which describes some of the other studies made on the lake, is dedicated to John, who was both a close personal friend and a brilliant colleague. Along the ~650 km length of the lake we occupied 18 stations and sampled the major inflowing streams. The CI concentration of the lake waters below ~150m (depth of the epilimnion) is constant (27.8ppm), so that temperature is the only hydrographic variable, and distinctive profiles occur in the two major deep basins (North & South, = NB and SB). In the NB from 100 to 1200m, T° C decreases smoothly to 400m, below which are two ~ isothermal layers extending down to a sharp discontinuity at 700m, followed by a decrease to an nderline{in-situ} minimum (23.32° C at 870m, the coldest water in Lake Tanganyika). The lower-most 300m of the profile is essentially adiabatic, with a bottom T = 23.32° C. The 700m T discontinuity is associated witha sharp cusp in methane concentration, which increases smoothly with depth from zero at the base of the mixed layer to 2.5 cc/kg at 700m, and then increases rapidly to 5.0 cc/kg at 1200m. In the SB, T decreases smoothly to 600m depth, below which is an almost isothermal layer to 1100m, followed by an ~ adiabatic gradient for 300m, to 23.40° C at 1400m. In this basin the CH4 profile is a smoothly continuous curve from 100-1200m, showing that the effective sill-depth between the two basins is at ~700m. Helium isotope profiles also show distinctive profiles in the two deep basins. In the NB, the 4He profile increases downward from atmospheric saturation to a smooth maximum at 450m (2.26 x saturation) and a 3He/4He ratio anomaly ? (3He) = -40% of atmospheric value). In the SB there is a similar though less marked He maximum at 900m. These extrema show the depths of injection of He from crustal sources, which in both basins has a 3He/4He ratio of 0.28 x atmospheric, close to the ratio in radiogenic helium. The He concentration requires a saturation T of 15° C at the present level of 773m above sealevel. If the deep water has not changed and was saturated at the present 23° C, the required lake level is ~250m below the present level. Co2 and 13C data show production of light CO2 at 220m, the depth of a ? (13C) minimum, and on the lake bottom where heavy CO2 is produced by CH4 production. Other data to be discussed as time permits include stable isotopes (D and 18O, enriched in deep water), 14C, tritium, 226Ra, 210Pb, and dissolved N2, Ne, and Ar. Our logistical work was supported by UNDP-FAO. G.W. Coulter (UNDP, Burundi), Ray Weiss (SIO), and Valerie Craig (SIO) participated in the expedition work at sea and on land.

  10. Mathematical Modelling of Melt Lake Formation on an Ice Shelf

    NASA Astrophysics Data System (ADS)

    Buzzard, Sammie; Feltham, Daniel; Flocco, Daniela; Sammonds, Peter

    2015-04-01

    The accumulation of surface meltwater on ice shelves can lead to the formation of melt lakes. These structures have been implicated in crevasse propagation and ice shelf collapse; the Larsen B ice shelf was observed to have a large amount of melt lakes present on its surface just before its collapse in 2002. Through modelling the transport of heat through the surface of the Larsen C ice shelf, where melt lakes have also been observed, this work aims to provide new insights into the ways in which melt lakes are forming and the effect that meltwater filling crevasses on the ice shelf will have. This will enable an assessment of the role of meltwater in triggering ice shelf collapse. The Antarctic Peninsula, where Larsen C is situated, has warmed several times the global average over the last century and this ice shelf has been suggested as a candidate for becoming fully saturated with meltwater by the end of the current century. Here we present results of a 1D mathematical model of heat transfer through an idealised ice shelf. When forced with automatic weather station data from Larsen C, surface melting and the subsequent meltwater accumulation, melt lake development and refreezing are demonstrated through the modelled results. Furthermore, the effect of lateral meltwater transport upon melt lakes is examined. This will be developed through the estimations of meltwater catchment areas and the fraction of the ice shelf where melt lakes are present. Investigating the role of meltwater in ice shelf stability is key as collapse can affect ocean circulation and temperature, and cause a loss of habitat. Additionally, it can cause a loss of the buttressing effect that ice shelves can have on their tributary glaciers, thus allowing the glaciers to accelerate, contributing to sea level rise.

  11. ADVANCING GREAT LAKES HYDROLOGICAL SCIENCE

    E-print Network

    ADVANCING GREAT LAKES HYDROLOGICAL SCIENCE THROUGH TARGETED BINATIONAL COLLABORATIVE RESEARCH by Andrew d. Gronewold And Vincent Fortin ImprovIng HydrologIcal modelIng predIctIons In tHe great lakes wh for advancing the state of the art in Great Lakes regional climate, hydrological, and hydrodynamic modeling when

  12. GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY

    E-print Network

    #12;#12;GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY ANNUAL REPORT FY 1985 December 1985 Eugene J and Atmospheric Research Environmental Research Laboratories Great Lakes Environmental Research Laboratory 2300 .........................Contracts and Grants 48 Front Cover: Water levels on the Great Lakes have been in a high regimefor the past

  13. Living With the Great Lakes

    NSDL National Science Digital Library

    This site was developed to assist students and educators with learning about the Great Lakes. The links provide materials on basic earth science concepts, a set of lesson plans on the lakes, and other Great Lakes topics. Concepts covered include Langmuir circulation, longshore current and beach drift, sediments, stream flow, seasonal stratification and water quality.

  14. Michigan: The Great Lakes State

    ERIC Educational Resources Information Center

    McKay, Sandra Lee; La Luzerne-Oi, Sally

    2009-01-01

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

  15. The hydrology of Lake Victoria

    Microsoft Academic Search

    B. S. Newell

    1960-01-01

    Evidence is presented to show that Lake Victoria is triply stratified the whole year round. The conclusions of FISH (1957) that a uninodal internal seiche operates in the lake is shown to be invalid, and the oscillations of isotherms at E.A.F.R.O. Open Lake Station observed over some years are explained by the day to day wind changes.

  16. Crater Lake Blue Through Time

    E-print Network

    Torgersen, Christian

    trout, both introduced Lake Facts U.S. Geological Survey and the National Park Service Partnership funded scientific surveys of the lake, which encouraged President Roosevelt to sign a bill in 1902 givingCrater Lake Blue Through Time Blue is the color of constancy, hence the term true blue

  17. Some Indices of Lake Productivity

    Microsoft Academic Search

    John B. Moyle

    1949-01-01

    In an attempt to evaluate lake-survey procedures some of the chemical, physical, and biological measurements that have been considered possible indices of lake productivity have been examined in the light of 11 years of lake surveys and 6 years of pond rearing of yellow pikeperch. In Minnesota waters total alkalinity and total phosphorus appear to be the most valuable indices.

  18. California Sea Grant 1 California Sea Grant

    E-print Network

    Jaffe, Jules

    California Sea Grant 1 California Sea Grant Strategic Plan 2010­2013 #12;2 Strategic Plan 2010­2013 The National Sea Grant College Program, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, supported this publication under NOAA grant number NA08OAR4170669, project number C/P-1 through

  19. Viruses in Antarctic lakes

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  20. Images of Lake Tahoe

    NSDL National Science Digital Library

    2012-07-13

    When Grace Greenwood encountered Lake Tahoe in the 1870s, she remarked that "Tahoe is the most beautiful lake I have ever beheld. It is an emerald on the brow of the mountain. Marvellously clear and sparkling, it is surrounded by the most enchanting scenery, and is altogether a surprise, a wonder, a delight." Generations of tourists and locals have enjoyed its charms since. And this remarkable digital collection provides over 1,000 images of the surrounding area. The collection was created by the University of Nevada-Reno's Special Collections Department. Visitors can search the entire collection by keywords and they may also wish to just use the "View All Images" link. It is amazing to think about the changes around the area that have occurred in the past several decades alone, and it is neat to see some of the early resorts that began to pop up on the lake's shores in the early 20th century.

  1. Lake Tahoe Data Clearinghouse

    NSDL National Science Digital Library

    Alexander Evans

    Created and maintained by the U.S. Geological Survey (USGS) in partnership with federal, state, tribal, and local agencies and groups, this is a major gateway to information and data on Lake Tahoe and its basin. The primary goal of this clearinghouse is to facilitate the coordination of research, monitoring, and environmental management activities in the Lake Tahoe Basin, and to ensure the widest possible access to data and information resulting from such activities. Users have access to a wide range of data and GIS products. Examples include: high quality digital maps for the Lake Tahoe area (including Tahoe hydrography, roads, vegetation cover, forests, timber, soils), digital orthophoto quadrangles, and digital elevation models. Some of the data resides on the USGS server at the Western Mapping Center, Menlo Park, California. The bulk of the data and information, located in databases maintained by the partnering agencies, is accessible via hypertext links.

  2. Images of Lake Tahoe

    NSDL National Science Digital Library

    Lake Tahoe is quite the sight anytime of year. As traveler Grace Greenwood noted in 1873, the lake "is an emerald on the brow of the mountain." This splendid digital collection from the University of Nevada-Reno brings together hundreds of photographs documenting this unique body of water that sits on the California and Nevada border. All told, there are over 1,000 items here that document the lake's transformation from placid and pristine to buzzing with tourism activity by the mid 20th century. Along the way, visitors can view items by date of creation, category, and photographer. Keyword searches can be quite revealing and first-time visitors might like to start with "beach," "casino," or "Emerald Bay."

  3. Fungal life in the dead sea.

    PubMed

    Oren, Aharon; Gunde-Cimerman, Nina

    2012-01-01

    The waters of the Dead Sea currently contain about 348 g/l salts (2 M Mg(2+), 0.5 M Ca(2+), 1.5 M Na(+), 0.2 M K(+), 6.5 M Cl(-), 0.1 M Br(-)). The pH is about 6.0. After rainy winters the surface waters become diluted, triggering development of microbial blooms. The 1980 and 1992 blooms were dominated by the unicellular green alga Dunaliella and red Archaea. At least 70 species (in 26 genera) of Oomycota (Chromista), Mucoromycotina, Ascomycota, and Basidiomycota (Fungi) were isolated from near-shore localities and offshore stations, including from deep waters. Aspergillus and Eurotium were most often recovered. Aspergillus terreus, A. sydowii, A. versicolor, Eurotium herbariorum, Penicillium westlingii, Cladosporium cladosporioides, C. sphaerospermum, C. ramnotellum, and C. halotolerans probably form the stable core of the community. The species Gymnascella marismortui may be endemic. Mycelia of Dead Sea isolates of A. versicolor and Chaetomium globosum remained viable for up to 8 weeks in Dead Sea water; mycelia of other species survived for many weeks in 50% Dead Sea water. Many isolates showed a very high tolerance to magnesium salts. There is no direct proof that fungi contribute to the heterotrophic activity in the Dead Sea, but fungi may be present at least locally and temporarily, and their enzymatic activities such as amylase, protease, and cellulase may play a role in the lake's ecosystem. PMID:22222829

  4. Simulation of a proposed emergency outlet from Devils Lake, North Dakota

    USGS Publications Warehouse

    Vecchia, Aldo V.

    2002-01-01

    From 1993 to 2001, Devils Lake rose more than 25 feet, flooding farmland, roads, and structures around the lake and causing more than $400 million in damages in the Devils Lake Basin. In July 2001, the level of Devils Lake was at 1,448.0 feet above sea level1, which was the highest lake level in more than 160 years. The lake could continue to rise to several feet above its natural spill elevation to the Sheyenne River (1,459 feet above sea level) in future years, causing extensive additional flooding in the basin and, in the event of an uncontrolled natural spill, downstream in the Red River of the North Basin as well. The outlet simulation model described in this report was developed to determine the potential effects of various outlet alternatives on the future lake levels and water quality of Devils Lake. Lake levels of Devils Lake are controlled largely by precipitation on the lake surface, evaporation from the lake surface, and surface inflow. For this study, a monthly water-balance model was developed to compute the change in total volume of Devils Lake, and a regression model was used to estimate monthly water-balance data on the basis of limited recorded data. Estimated coefficients for the regression model indicated fitted precipitation on the lake surface was greater than measured precipitation in most months, fitted evaporation from the lake surface was less than estimated evaporation in most months, and ungaged inflow was about 2 percent of gaged inflow in most months. Dissolved sulfate was considered to be the key water-quality constituent for evaluating the effects of a proposed outlet on downstream water quality. Because large differences in sulfate concentrations existed among the various bays of Devils Lake, monthly water-balance data were used to develop detailed water and sulfate mass-balance models to compute changes in sulfate load for each of six major storage compartments in response to precipitation, evaporation, inflow, and outflow from each compartment. The storage compartments--five for Devils Lake and one for Stump Lake--were connected by bridge openings, culverts, or natural channels that restricted mixing between compartments. A numerical algorithm was developed to calculate inflow and outflow from each compartment. Sulfate loads for the storage compartments first were calculated using the assumptions that no interaction occurred between the bottom sediments and the water column and no wind- or buoyancy-induced mixing occurred between compartments. However, because the fitted sulfate loads did not agree with the estimated sulfate loads, which were obtained from recorded sulfate concentrations, components were added to the sulfate mass-balance model to account for the flux of sulfate between bottom sediments and the lake and for mixing between storage compartments. Mixing between compartments can occur during periods of open water because of wind and during periods of ice cover because of water-density differences between compartments. Sulfate loads calculated using the sulfate mass-balance model with sediment interaction and mixing between compartments closely matched sulfate loads computed from historical concentrations. The water and sulfate mass-balance models were used to calculate potential future lake levels and sulfate concentrations for Devils Lake and Stump Lake given potential future values of monthly precipitation, evaporation, and inflow. Potential future inputs were generated using a scenario approach and a stochastic approach. In the scenario approach, historical values of precipitation, evaporation, and inflow were repeated in the future for a particular sequence of historical years. In the stochastic approach, a statistical time-series model was developed to randomly generate potential future inputs. The scenario approach was used to evaluate the effectiveness of various outlet alternatives, and the stochastic approach was used to evaluate the hydrologic and water-qu

  5. Tracing the sources of PCDD/Fs and PCBs in Lake Baikal

    SciTech Connect

    Mamontov, A.A.; Mamontova, E.A.; Tarasova, E.N.; McLachlan, M.S.

    2000-03-01

    Lake Baikal is a unique freshwater ecosystem that has been declared a UNESCO World Heritage Site. It contains high levels of PCBs, and Baikal seal were recently found to have PCDD/F concentrations comparable to those in the Baltic Sea. In this work fish and soil were analyzed to trace the sources of these compounds to the lake. The fish samples indicated that the PCDD/F and PCB contamination of Lake Baikal does not originate from background inputs and that the contamination increases from north to south. The soil inventory was determined at 34 sites around Lake Baikal and in the Angara River valley. For the PCDD/Fs and most PCBs, the soil inventory is a good approximation of the cumulative atmospheric deposition. It varied over a factor of 1,000, with the highest levels in Usol'ye Sibirskoe, a city 110 km north of the southwestern tip of the lake in the highly industrialized Angara River valley, and the lowest values in the pristine areas to the northeast of the lake. A continuous decrease in the soil inventory was observed moving from Usol'ye S. up the Angara River valley to Lake Baikal and from there northeastward along the lake.

  6. The study of coastal meromictic water basins in the Kandalaksha Gulf of the White Sea by spectral and physicochemical methods

    NASA Astrophysics Data System (ADS)

    Kharcheva, Anastasia V.; Meschankin, Andrey V.; Lyalin, Igor I.; Krasnova, Elena D.; Voronov, Dmitry A.; Patsaeva, Svetlana V.

    2014-01-01

    Research is initiated to study water samples from stratified water basins in the Kandalaksha Gulf of the White Sea at different stages of their separation from the sea. The objects of research are lakes Elovoe and Nizhnee Ershovskoe located close to the Nikolai Pertsov White Sea Biological Station. Depth profiles of physico-chemical characteristics such as temperature, salinity, pH and dissolved oxygen were measured. Brightly colored green water layers were found in both lakes. Concentrations of photosynthetic organisms were estimated using absorption and fluorescence spectra of water samples from various depths.

  7. Mercury Sources to Lake Ozette and Lake Dickey: Highly Contaminated Remote Coastal Lakes, Washington State, USA

    Microsoft Academic Search

    Chad Van Furl; John A. Colman; Michael H. Bothner

    2010-01-01

    Mercury concentrations in largemouth bass and mercury accumulation rates in age-dated sediment cores were examined at Lake\\u000a Ozette and Lake Dickey in Washington State. Goals of the study were to compare concentrations in fish tissues at the two lakes\\u000a with a larger statewide dataset and examine mercury pathways to the lakes. After accounting for fish length, tissue concentrations\\u000a at the

  8. Observing lake ice phenology across Alaska using in situ sensors, aircraft, and satellites

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Jones, B. M.; Grosse, G.; Bodony, K.; Sturdivant, E.; Frey, K. E.

    2013-12-01

    The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. Thus, there is a need to understand lake ice phenology at multiple scales from small to large lakes and across lake-rich landscapes. In this study, we observed ice-out timing for large lakes using MODIS imagery in eleven lake districts across Alaska from 2007 - 2012 and validated these and expanded to smaller lakes using in situ sensors and shore-based cameras. Over this six year period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low interannual variability. Approximately 80% of the variation in ice out timing was explained by the 0°C air temperature isotherm date (ATID) and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Inter-district analysis of coherence showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June - July) and regional climatology is strongly sea-ice influenced. Following this baseline analysis to document spatial and temporal variability, Alaska experienced record cold spring conditions in 2013. This apparent anomaly from long-term trends of earlier springs in northern latitudes provided an opportunity to validate empirical models and look at lake responses under conditions more representative of times before modern warming. In 2013 mean ice-out for all study lakes was 13 days later than mean for the previous six year observation period. The lower latitude and interior lake districts Denali, Kenai, and Minto Flats had ice-free conditions >18 days later in 2013 than the baseline period compared to higher latitude and coastal districts Beringia, Yukon-Kuskokwim Delta, and Arctic Coastal Plain became ice-free well within the range of recent interannual variability. Observations from this late spring are evaluated in relation to models based on 0°C ATID for Alaska lake districts and accumulated freezing degree days (AFDD) for the Koyukuk lake district where a longer period of lake ice phenology data is available from aircraft surveys. To place short term lake ice phenology into a longer term context, we used a combination of remote sensing (optical and radar satellites imagery), in situ sensors, and ice growth and decay models on one large lake of regional significance to Arctic Alaska, Teshekpuk Lake. Because of its large area (850 km2) and shallow depth (7 m maximum), Teshekpuk may have the longest annual ice-cover duration of any lake in Alaska and thus a sentinel for analysis of Arctic climate change. Our long-term analysis (1947 to present) of both ice-out and ice-on timing suggest a mean open-water duration of 63 days and moderate trend towards an increasing open-water season (0.5 days per year, r2=0.21) primarily driven by earlier ice-out timing. Our analysis also suggests that Teshekpuk Lake may have maintained at partial perennial ice cover in 1956 and 1969. Future work on this lake, as well the ice phenology of other lakes and lake districts in Arctic and Boreal regions, will seek to understand both the limnological and climatological consequences ice phenology in the context of climate change and variability.

  9. Great Lakes Lab

    NASA Astrophysics Data System (ADS)

    The Great Lakes Environmental Research Laboratory (GLERL) would close under President Reagan's fiscal year 1984 budget proposal issued on January 31, 1983. GLERL, established in 1974, conducts experimental research in the field and laboratory on the physics, chemistry, and biology of the Great Lakes, their watersheds, sediments, and overlying atmosphere. Closing the lab would represent a cut of more than $3.6 million from the ocean research program, which is part of the National Oceanic and Atmospheric Administration's (NO A A) ocean and coastal programs activity. Also, it would mean dismissing a staff of 90, according to Eugene Aubert, director of GLERL.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  11. Assessment of PAHs in water and fish tissues from Great Bitter and El Temsah lakes, Suez Canal, as chemical markers of pollution sources

    Microsoft Academic Search

    Tarek O. Said; Nadia A. El Agroudy

    2006-01-01

    Sea water and fish tissue samples were collected from nine sampling stations from the Great Bitter and El Temsah lakes in the Suez Canal and analysed for polycyclic aromatic hydrocarbon (PAH). The compositions of PAH determined in the dissolved fraction of sea water were measured in order to use them as chemical markers for identifying different sources of PAH pollution

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

    Microsoft Academic Search

    Gary H. Heinz; H. Franklin Percival; Michael L. Jennings

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A

  13. Expansion of tubenose gobies Proterorhinus semilunaris into western Lake Erie and potential effects on native species

    USGS Publications Warehouse

    Kocovsky, P.M.; Tallman, J.A.; Jude, D.J.; Murphy, D.M.; Brown, J.E.; Stepien, C.A.

    2011-01-01

    The Eurasian freshwater tubenose goby Proterorhinus semilunaris (formerly Proterorhinus marmoratus) invaded the Laurentian Great Lakes in the 1990s, presumably via ballast water from transoceanic cargo ships. Tubenose gobies spread throughout Lake St. Clair, its tributaries, and the Detroit River system, and also are present in the Duluth-Superior harbor of Lake Superior. Using seines and bottom trawls, we collected 113 tubenose gobies between July 2007 and August 2009 at several locations in western Lake Erie. The number and range of sizes of specimens collected suggest that that tubenose gobies have become established and self-sustaining in the western basin of Lake Erie. Tubenose gobies reached maximum densities in sheltered areas with abundant macrophyte growth, which also is their common habitat in native northern Black Sea populations. The diet of tubenose gobies was almost exclusively invertebrates, suggesting dietary overlap with other benthic fishes, such as darters (Etheostoma spp. and Percina sp.), madtoms (Noturus spp.), and sculpins (Cottus spp.). A single mitochondrial DNA haplotype was identified, which is the most common haplotype found in the original colonization area in the Lake St. Clair region, suggesting a founder effect. Tubenose gobies, like round gobies Neogobius melanostomus, have early life stages that drift owing to vertical migration, which probably allowed them to spread from areas of colonization. The Lake St. Clair-Lake Erie corridor appears to have served as an avenue for them to spread to the western basin of Lake Erie, and abundance of shallow macrophyte-rich habitats may be a key factor facilitating their further expansion within Lake Erie and the remainder of the Laurentian Great Lakes.

  14. A Tale of Two Cataclysmic Earthquakes: 39 and 52 kyr BP, Dead Sea Transform, Israel; a Multi-archive Study

    Microsoft Academic Search

    E. J. Kagan; M. Stein; M. Bar-Matthews; A. Agnon

    2007-01-01

    We have documented earthquake histories in four lacustrine sites and a cave in the Dead Sea Transform region in central Israel. The lacustrine Lake Lisan (last Glacial paleo-Dead Sea) sites include: Massada Plain (M1b), Perazim (PZ1), Tovlan (NT), and Tamar (TM). They are up to 110 kms apart, along the Dead Sea Basin. These lacustrine sites have a variety of

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

    Microsoft Academic Search

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

    2006-01-01

    Many of the McMurdo Dry Valleys lakes of Antarctica exhibit saline to hypersaline bottom waters whose chemistry is distinct from that of sea water. The source and relative abundance of dissolved Cl, Br, and I in these unusual waters has been modified by several potential processes including: seawater incursions, water- rock interactions, microbial scavenging, glacial melting and precipitation, and atmospheric

  16. RESEARCH ON WATER QUALITY AND BIOLOGICAL CONDITIONS OF GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    Presentation is to 4th - 10th grade teachers participating in a NSF-funded, Sea-Grant led program for enhancing science curricula in schools by educating teachers about research and issues in some focal area (Great Lakes in this case). Background information provided on ecology ...

  17. PROCEEDINGS OF THE GREAT LAKES ICE RESEARCH WORKSHOP* Held October 18-19, 1983

    E-print Network

    University Fawcett Center for Tomorrow Columbus, OH CO-SPONSORED BY OHIO SEA GRANT AND NOAA, ERL, GLERL;Foreword A workshop was held on October 18-19, 1983, at the Fawcett Center for Tomorrow, the Ohio State it to our Great Lakes Ice Research Workshop. As you can see from the wide body of people here

  18. Lake Ontario: food web dynamics in a changing ecosystem (1970–2000)

    Microsoft Academic Search

    E. L. Mills; J. M. Casselman; R. Dermott; J. D. Fitzsimons; G. Gal; K. T. Holeck; J. A. Hoyle; O. E. Johannsson; B. F. Lantry; J. C. Makarewicz; E. S. Millard; I. F. Munawar; M. Munawar; R. O'Gorman; R. W. Owens; L. G. Rudstam; T. Schaner; T. J. Stewart

    2003-01-01

    We examined stressors that have led to profound ecological changes in the Lake Ontario ecosystem and its fish community since 1970. The most notable changes have been reductions in phosphorus loading, invasion by Dreissena spp., fisheries management through stocking of exotic salmonids and control of sea lamprey (Petromyzon marinus), and fish harvest by anglers and double-crested cormorants (Phalacrocorax auritus). The

  19. Remote sensing of Great Lakes water quality: Case studies of Saginaw Bay, Lake Huron and western Lake Erie

    NASA Astrophysics Data System (ADS)

    Budd, Judith Wells

    Zebra mussels (Dreissena polymorpha) have initiated ecosystem-level water quality changes in the Great Lakes. Increased water clarity, as well as decreased chlorophyll abundances, have fundamentally altered the optical characteristics of shallow coastal basins and bays. The occurrence of major blooms of blue-green algae (predominantly Microcystis) in western Lake Erie and Saginaw Bay have also affected water clarity. Whereas in situ water quality studies rely on point data from shipboard sampling, laboratory experiments and enclosures, the scale and magnitude of Dreissena and Microcystis effects on surface water quality suggest an additional research application that involves satellite remote sensing. My thesis is that remote sensing technology will facilitate timely and cost-effective analyses of Dreissena and Microcystis effects on water quality. Advanced Very High Resolution Radiometer (AVHRR) images estimate sea surface temperatures and reflectances in Saginaw Bay and western Lake Erie. The thermal bands document surface water mass movements over zebra mussel beds, whereas red and near-infrared channels estimate total suspended solids and Secchi disk depth. The thermal study traces thermal bar formation and movement offshore and the seasonal development of the warm coastal nearshore zone (Chapter 2). AVHRR reflectance imagery of Saginaw Bay from 1987 to 1993 documents the historical impact of Dreissena filtering on water quality variables (Chapter 3). A mixed general linear model describes seasonal and interannual changes in water quality before and after zebra mussels were established in Saginaw Bay. Imagery of extensive surface blooms of the toxic blue-green algae Microcystis in western Lake Erie illustrates AVHRR's ability to resolve spatial patterns (Chapter 4). Mean reflectances in the Maumee Bay region doubled from 2.0 percent in early August to 4.5 percent during mid-September, when the bloom was at its peak. Estimates of bloom spatial extent ranged from 250 to 1000 kmsp2. Satellite image analysis complements shipboard sampling efforts by providing frequent overflights and synoptic coverage of surface waters. Furthermore, satellite archives facilitate retrospective analyses during periods when in situ water quality data are not available. The vast opportunities for detailed spatial analyses of surface water variables enable cost-effective, long-term evaluation of zebra mussel and Microcystis effects in the Great Lakes.

  20. Bacterial activities in the Dead Sea, 1980-1991: survival at the upper limit of salinity

    Microsoft Academic Search

    Aharon Oren

    1992-01-01

    Since the mass development of halophilic bacteria in 1980 and the subsequent decline of the community in 1982, no new mass\\u000a development of bacteria has occurred in the Dead Sea, and bacterial numbers have remained extremely low. The lake’s salinity,\\u000a and more specifically the divalent cation concentration, have increased greatly during the last ten years. To quantitate the\\u000a activity of

  1. Short-term level rises during the Lake Lisan desiccation - possible correlations to volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bookman, Revital; Filin, Sagi; Marco, Shmuel

    2010-05-01

    Short-term decrease in global temperature in response to volcanic eruptions is known from modern events. The eruption of Mount Pinatubo (June, 1991) led to air temperature anomaly throughout the Middle East and resulted in an ecological response and coral death in the Red Sea (Genin et al., 1992). The following winter was characterized by above-average precipitation in the Dead Sea drainage area, which resulted in changes in the lake water column structure and anomalous biological productivity. A 2-m level rise interrupted the dramatic partly-anthropogenic Dead Sea level-drop. These unusual limnological conditions were also associated with the development of a massive levelled terrace on the lake shores. The modern shore terraces and similar geomorphic features left during the desiccation of Lake Lisan on the margins of the Dead Sea Basin were analyzed using airborne laser scanning (LiDAR), which provides three-dimension geometry with high level accuracy, high resolution, large extent, and coverage of inaccessible areas, all leading to unprecedented level of surface detail. Preliminary results identified about 13 shore terraces on the basin's escarpment along Mineral Beach. These terraces were developed during the transition from the Last Glacial Maximum Lake Lisan high-stands to the Holocene low-stands between 14,700 years BP and 13,800 BP based on the Lake Lisan level curve (Bartov et al., 2003). We suggest using the modern analogue of Dead Sea level rise during the winter of 1991-92 as an indicator for climatic respond to major volcanic eruptions, like the Pinatubo, in the past. The steep topography and fast Lake Lisan retreat favoured the preservation of the terraces that record the short-term, perhaps even annual, level rise events. The range of terrace height is 1 - 6.5 m and using the Dead Sea Basin hypsometric curve the corresponding volumes of freshwater inputs required for the level rises are ~ 1.9 - 13.7 × 109 m3. Evidence for major paleo-eruptions is embedded in the GISP2 ice core record as atmospheric SO4 concentration peaks (>75 ppb). Using the Greenland ice record, the number of events and their magnitude is correlated with high consistency (R2=0.8) to the Lake Lisan desiccation terrace record. Hence, Lake Lisan shore terraces record provides useful linkage to global scale teleconnection atmospheric information. We further plan to use atmospheric simulations to quantify the short-term climatic effect of volcanic eruptions on a regional scale.

  2. Temperature Trends in Montane Lakes

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  3. Abundance indices for determining the status of lake trout restoration in Michigan waters of Lake Superior

    USGS Publications Warehouse

    Hansen, Michael J.; Schorfhaar, Richard G.; Peck, James W.; Selgeby, James H.; Taylor, William W.

    1995-01-01

    Self-sustaining populations of lake trout Salvelinus namaycush have returned to most areas in Lake Superior, but progress toward achieving historic commercial yields has been difficult to measure because of unrecorded losses to predation by sea lamprey Petromyzon marinus and to fisheries. Consequently, we developed restoration targets (catch per effort, CPE; geometric mean number per kilometer of 114-mm stretch-meaure gill net during 1929-1943, when historic yields were sustained) from linear relationships between CPE in commercial and assessment fisheries in Michigan. Target CPEs for lake trout restoration were higher and less variable than the modern CPEs in all areas. Modern CPEs generally increased during the 1970s and early 1980s but declined during the late 1980s and early 1990s. Modern CPEs were highest in western Michigan from the Keweenaw Peninsula to Marquette (71 to 81% of target CPEs), but coefficients of variation (CV,SD/mean) of mean CPEs were 1.4 to 2.4 times greater than target CVs. Around Munising, the modern CPE was lower (41% of the target CPE), whereas the CV was 1.9 times greater than the target CV. Around Grand Marais, the modern CPE was lowest among all areas (17% of the target CPE), but the CV was nearly the same (1.1 times the target CV). In Whitefish Bay, the modern CPE was only 28% of the target CPE and the CV was 9.0 times greater, though the modern period was based on only the years 1979-1982 and 1984-1985. Further progress in restoration in most areas can be achieved only if fishery managers adequately protect existing stocks of wild fish from sea lamprey predation and fishery exploitation.

  4. Lake County Paratransit Survey Final Report Prepared for the Lake County Coordinated Transportation Services Committee

    E-print Network

    Illinois at Chicago, University of

    Lake County Paratransit Survey Final Report Prepared for the Lake County Coordinated Transportation............................................................................25 4. Appendix A: Lake County Paratransit Survey Instrument.................................27 #12;2 Lake County Paratransit Survey Final Report Executive Summary The Urban Transportation Center

  5. 77 FR 9652 - Proposed CERCLA Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-17

    ...Administrative Cost Recovery Settlement; Lake Linden Superfund Site in Lake Linden, Houghton County, MI AGENCY: Environmental Protection...recovery of past response costs concerning the Lake Linden Superfund Site in Lake Linden, Houghton...

  6. Lake Huron Coast

    USGS Multimedia Gallery

    Great Lakes water availability studies conducted by the U.S. Geological Survey aim to help characterize how much water the Basin has now, how water availability is changing, and how much water it can expect to have in the future....

  7. Wisconsin's Great Lakes Shipwrecks

    NSDL National Science Digital Library

    Underwater videos and photos of shipwrecks in Lakes Superior and Michigan, information on individual vessels, map of the shipwrecks, searchable database, historical newspaper search, a glossary of nautical terms, interactive features and information for divers. Extensive resource, classroom activities are available via a linked site.

  8. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

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

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

  9. Geochemistry of Saline Lakes

    NASA Astrophysics Data System (ADS)

    Jones, B. F.; Deocampo, D. M.

    2003-12-01

    Saline lakes are important environmental features, with significant geochemical impacts on ecology, water resources, and economic activity around the world. Ancient sediments within saline lake basins also offer important sedimentary archives of past climates and tectonics, because such deposits can record significant hydrologic variations.Saline lake geochemistry is the product of a complex system involving meteoric precipitation, weathering, groundwater, evaporation, precipitation-dissolution reactions, and biotic activity. Its study is therefore an inherently interdisciplinary effort, and substantial reviews of the subject have emphasized relevant aspects of the hydrology (Rosen, 1994), mineralogy ( Spencer, 2000), sedimentology ( Hardie et al., 1978; Smoot and Lowenstein, 1991), and evolutionary pathways taken by progressively evaporated waters ( Eugster and Hardie, 1978).The purpose of this paper is to summarize the geochemistry of saline lake basins throughout the world, from dilute inflow to evaporated brine. Following the general approach of Eugster and Hardie (1978), we will review the theoretical background of the evolution of closed basin waters, and then selected field examples that are representative of the major water types. In this work, we have assigned an increased importance to the effect of magnesium salts on brine evolution pathways, and have incorporated this into new models of brine evolution and evaporite precipitation. We follow Chapter 5.16 in referring to waters with total dissolved solids greater than 3.5×104 mg L-1 as true "brines," and those with from 1 mg L-1 to 104 mg L-1 as "brackish."

  10. LAKE TAHOE VISIBILITY STUDY

    EPA Science Inventory

    Visibility monitoring and airborne particulate sampling in the Lake Tahoe Basin were used to document visual air quality levels and to assess the relative impacts of major contributing emission source categories. Visibility data were obtained by long path contrast and particle sc...

  11. MONITORING OF LAKE ECOSYSTEMS

    Microsoft Academic Search

    Alois Herzig

    The essential component of management strategies for the conservation of lake biota is a reasonably complete understanding of the factors and processes regulating the composition, organization and dynamics of the com- munities. One aspect of the habitat quality is the trophic state, which can be defined on the basis of, e.g. nutrient content, primary production or secondary production. Within the

  12. The lakes of Titan

    Microsoft Academic Search

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

    2007-01-01

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for

  13. CONTOURITES IN LAKE SUPERIOR

    EPA Science Inventory

    Contour currents influence sedimentation in an area 15 km wide and 65 km long at the base of the slope off the Keweenaw Peninsula in Lake Superior, northwestern Michigan. Seismic-reflection profiles (3.5 kHz) from this area show distinct wavy reflectors in a scoured trough at a d...

  14. Grays Lake Ecosystem

    NSDL National Science Digital Library

    The Northern Prairie Wildlife Research Center (NPWRC) has posted several new (or newly online) resources on wetlands and birds. This resource, from the US Geological Survey, focuses on the Grays Lake National Wildlife Refuge, and current and previous research conducted there on bird and plant species.

  15. Lake Michigan: Nearshore Variability

    EPA Science Inventory

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

  16. Lake Ontario: Nearshore Variability

    EPA Science Inventory

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

  17. The Lake Wobegon Effect.

    ERIC Educational Resources Information Center

    Phillips, Gary W.

    1990-01-01

    In 1987, a survey report by J. Cannell was published criticizing state reports based on national standardized testing of elementary school students that indicated that all 50 states were above the national average. This phenomenon--known as the "Lake Wobegon Effect"--is analyzed. Technical problems with the study are considered. (TJH)

  18. Conochilus in Lake Washington

    Microsoft Academic Search

    W. T. Edmondson; Arni H. Litt

    1987-01-01

    The rotifer Conochilus unicornis appeared in Lake Washington sporadically and usually in small numbers during a total of 28 years of observation since 1933. Conochilus hippocrepis was present even less frequently until the 3 year period 1977–1979, when it became extraordinarily abundant. The abundances of food organisms and known predators have been examined.

  19. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

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

  20. Climate Factors Contributing to Streamflow Inputs and Extreme Water-level Deviations from Long-term Averages for Lakes Superior and Michigan-Huron

    NASA Astrophysics Data System (ADS)

    Anderson, M. T.; Stamm, J. F.

    2014-12-01

    The Great Lakes are a highly valued freshwater resource of the United States and Canada. The Lakes are the focus of a science-based restoration program, known as the Great Lakes Restoration Initiative (GLRI). Physical and chemical factors, such as inflows and nutrient loads to the Great Lakes can affect ecosystem function, contribute to the spread of invasive species and increase the occurrence of harmful algal blooms. Since about 1999, water levels in Lakes Superior and Michigan-Huron have been at or below the long-term average (1918 to present). Analyses of streamflow trends for the period 1960 to 2012 in watersheds draining into Lakes Superior and Michigan-Huron showed a long-term decline in average inflows, which helps to explain the persistently below-average lake levels. Recent climatic conditions of October 2013 to August 2014 have contributed to a rapid rise in lake levels, most notably in Lake Superior. Lake Superior recently reached an elevation of 602.56 feet above sea level in August 2014, which is the highest level in 17 years. Coincident with this recovery was the development of a large algal bloom in Lake Erie in August of 2014 that shut down the Toledo, Ohio municipal water supply. These anomalous, extreme deviations from long-term average lake levels will be examined to better understand the forcing factors that contributed to changes in inflow volumes and lake-levels. Particular focus will be given to the climatology of years when changes in lake levels are most pronounced, such as; the measured lake-level declines during 1964-1965 and 1998-2000; and lake-level rises during 1973-1974, 1987-1989, and 2013-2014. The climatology of years with periods of algal blooms will also be examined such as, 2003, 2008, 2011 and 2014.

  1. Natural Reproduction by Stocked Lake Trout ( Salvelinus namaycush) and Hybrid (Backcross) Lake Trout in South Bay, Lake Huron

    Microsoft Academic Search

    David M. Anderson; John J. Collins

    1995-01-01

    In 1977, a study was begun in South Bay, Lake Huron, to assess the fitness of lake trout (Salvelinus namaycush) and lake trout backcrossed to splake (S. namaycush X S. fontinalis) for rehabilitating the lake. Mature lake trout were fivefold more abundant than mature backcross from paired stockings. Wild progeny consisting of 321 fry and 67 age-0 to age-2 juveniles

  2. Planetary science. The glitter of distant seas.

    PubMed

    Lorenz, Ralph

    2003-10-17

    It has long been known that Saturn's largest moon, Titan, has a thick nitrogen atmosphere, which obscures the underlying surface. In his Perspective, Lorenz highlights the report by Campbell et al., who have used the giant Arecibo and Green Bank radio telescopes as a radar to probe Titan's hidden surface. The surface appears to be distinct from those of the icy satellites of Jupiter, in both brightness and polarization. The new data show sharp spikes in the reflected microwave spectrum, indicating large, smooth areas of radar-dark material. These features suggest the widespread existence of lakes or seas of liquid hydrocarbons on Titan. PMID:14526089

  3. Paleoenvironmental reconstruction of Basa de la Mora glacial lake (Central Pyrenees) during the Holocene: preliminary results from palynological analyses

    Microsoft Academic Search

    Ana Pérez-Sanz; Penélope González-Sampériz; Mario Morellón; Anchel Belmonte; Carlos Sancho-Marcén; Blas Valero-Garcés; Ana Moreno; María. Teresa Rico; Juan Pablo Corella

    2010-01-01

    La Basa de la Mora (42° 33'N, 0° 20'E, 1914 m a.s.l.) is a glacial lake located at the central zone of the southern Pyrenees (Spain). It is a shallow lake with only 2.5 m water depth and 6.3 ha floodplain. Its position halfway between the Mediterranean Sea and the Atlantic Ocean lends to both mediterranean and oceanic climatic influences.

  4. Holocene regional and local vegetation history and lake-level changes in the Torneträsk area, northern Sweden

    Microsoft Academic Search

    Lena Barnekow

    2000-01-01

    A combination of pollen and macrofossil analyses from six lakes at altitudes between 370 and 999 m above sea level (a.s.l.) in the Torneträsk area reflect the Holocene vegetation history. The main field study area has been the Abisko valley at altitudes around 400 m a.s.l. The largest lake, Vuolep Njakajaure has annually laminated (varved) sediments. The chronology and sedimentation

  5. Regional Differences in Size-at-age of the Recovering Burbot ( Lota lota) Population in Lake Erie

    Microsoft Academic Search

    Martin A. Stapanian; Charles P. Madenjian; Jon Tost

    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

  6. Investigation of lagoon lakes in Kocacay delta by using remote sensing method.

    PubMed

    Irtem, Emel; Sacin, Yener

    2012-04-01

    Coasts are areas that are under the influence of the interaction of the air, water and land and attract attention with the abundance of their natural resources and therefore are subjected to excessive usage. This excessive usage may disturb the sensitive balance of the coast ecosystem. In this study, the changes in Arapçiftligi, Poyraz, Dalyan lakes area found in Kocacay delta located in the south coast of Marmara sea was evaluated between the periods of 2000 to 2007 with remote sensing method. These lakes, located on the shores, have a very sensitive naturally dynamic balance and very importance in terms of natural surroundings and the coastal zones management plan. It must be known the change of the lakes mentioned above area according to years. Research and applications have demonstrated the advantages of remote sensing and geographic information system techiques on river,delta, lake, lagoon lake, sensitivite areas in a lakeshore, coastal erosion etc. monitoring and management. In the study, we benefited from Erdas and Intergraph-Geomedia 6.1 image processing and GIS, and also from AutoCAD 2007 and NetCAD 4.0 computer-aided design (CAD) software. For 2000, 2001, 2005 and 2007 years (4 number) Landsat-5 TM satellite images belonging to the region were used. As a result of the study, Arapçiftligi, Dalyan and Poyraz lake areas, number of islets that are seen in the lakes were given in respect to years. Arapçiftligi lake shrank 29.5% in size in the years 2000 and 2007. The fact that the lake continued to get smaller in size even in periods of high precipitation may be due to the sediment flowing from the agricultural fields established close to the lake area. Dalyan and Poyraz lakes lost 60% in terms of their surface area in the years 2000 and 2007. In 2000-2001 periods, Dalyan and Poyraz lakes increased in size by 3.2%. The reason for this could be the excessive precipitation and the fact that the seawater from Marmara sea seeps into the lake. Protection of the natural balance of the lagoons can be possible by using a monitoring programme to be set in connection with a healthy, systematic and manageable data system. PMID:23424854

  7. Microbiology of Lonar Lake and other soda lakes

    PubMed Central

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

    2013-01-01

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

  8. Salton Sea Project, Phase 1. [solar pond power plant

    NASA Technical Reports Server (NTRS)

    Peelgren, M. L.

    1982-01-01

    A feasibility study was made for a salt gradient solar pond power plant in or near the Salton Sea of California. The conclusions support continuance 5-MWe proof-of-concept experiment, and ultimate construction by an electric utility company of a 600-MWe plant. The Solar Pond concept would be an environmental benefit to the Salton Sea by reversing the increasing salinity trend. The greatest cost drivers are the lake dike construction and pond sealing. Problems to be resolved include method of brine production from Salton Sea water for the first unit (which requires evaporation pond area and time), the high turbidity and color content of the Salton Sea water (which requires pretreatment), and other questions related to pond permeability, bio-activity and soil/brine chemical reactions. All technical and environmental problems appear solvable and/or manageable if care is taken in mitigating impacts.

  9. Lake Mead--clear and vital

    USGS Publications Warehouse

    Wessells, Stephen M.; Rosen, Michael

    2013-01-01

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

  10. LAKE MICHIGAN'S TRIBUTARY AND NEARSHORE FISH HABITATS

    E-print Network

    and goals of the Great Lakes Water Quality Agreement (GLWQA) (International Joint Commission 1988), in A Joint Strategic Plan for Management of Great Lakes Fisheries (hereafter, Joint Plan) (Great Lakes Fishery Commission 1997), and most recently in the Great Lakes Regional Strategy (Great Lakes Regional

  11. Predicting Maximum Lake Depth from Surrounding Topography

    EPA Science Inventory

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

  12. Lake Erie...Take a Bow.

    ERIC Educational Resources Information Center

    Canning, Maureen; Dunlevy, Margie

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

  13. Marine lake as in situ laboratory for studies of organic matter influence on speciation and distribution of trace metals

    NASA Astrophysics Data System (ADS)

    Mlakar, Marina; Fiket, Željka; Ge?ek, Sun?ana; Cukrov, Neven; Cuculi?, Vlado

    2015-07-01

    Karst marine lakes are unique marine systems, also recognized as in situ "laboratories" in which geochemical processes on a different scale compared to the open sea, can be observed. In this study, organic matter cycle and its impact on distribution of trace metals in the marine lake Mir, located on Dugi Otok Island, in the central part of the eastern Adriatic Sea, was investigated for the first time. Studied marine lake is small, isolated, shallow basin, with limited communication with the open sea. Intense spatial and seasonal variations of organic matter, dissolved and particulate (DOC, POC), and dissolved trace metals concentrations in the water column of the Lake are governed predominantly by natural processes. Enhanced oxygen consumption in the Lake during summer season, high DOC and POC concentrations and low redox potential result in occasional occurrence of anoxic conditions in the bottom layers with appearance of sulfur species. Speciation modeling showed that dissolved trace metals Cu, Pb and Zn, are mostly bound to organic matter, while Cd, Co and Ni are present predominantly as free ions and inorganic complexes. Trace metals removal from the water column and their retention in the sediment was found to depend on the nature of the relationship between specific metal and organic or inorganic phases, sulfides, Fe-oxyhydroxydes or biogenic calcite. The above is reflected in the composition of the sediments, which are, in addition to influence of karstic background and bathymetry of the basin, significantly affected by accumulation of detritus at the bottom of the Lake.

  14. Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario By W. E. Adams Jr1

    E-print Network

    Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario By W. E. Adams Jr1 Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake

  15. Groundwater and surface water interaction in flow-through gravel pit lakes.

    NASA Astrophysics Data System (ADS)

    Nella Mollema, Pauline; Antonellini, Marco

    2015-04-01

    Gravel pits are excavated in aquifers to fulfill the need for construction materials. Flow-through lakes form when the gravel pits are below the water table and fill with groundwater. In certain areas there are more than 60 of these lakes close together and their presence changes the drainage patterns and water- and hydrochemical budgets of a watershed. In flow-through gravel pit lakes, groundwater mixes with surface water and interacts with the atmosphere; outflow occurs only via groundwater. The lifespan of gravel pit lakes may be up to thousands of years as their depth to surface ratio is typically large and sedimentation rates are low. We have studied two gravel pit lake systems, a fluvial freshwater system in the Netherlands and a coastal brackish lake system in Italy. One Dutch gravel pit lake studied in detail is in part artificially replenished with Meuse River water for drinking water production that occurs downstream of the lake by water pumps. The Italian gravel pit lakes are fed by brackish groundwater that is a mix of freshwater from precipitation, Apennine Rivers and brackish (Holocene) Adriatic Sea water. Here, the drainage system of the low lying land enhances groundwater flow into the lake. Surface water evaporation is larger in temperate and Mediterranean climates than the actual evapotranspiration of pre-existing grassland and forests. The lakes, therefore, cause a loss of freshwater. The creation of water surfaces allows algae and other flora and fauna to develop. In general, water becomes gradually enriched in certain chemical constituents on its way through the hydrological cycle, especially as groundwater due to water-rock interactions. When groundwater ex-filtrates into gravel pit lakes, the natural flow of solutes towards the sea is interrupted. Hydrochemical analysis of ground- and surface waters, as well as chemical analysis of lake bottom sediments and stable H and O isotope data, show that gravel pit lake water is characterized (among others) by a higher pH, O2 and alkalinity and lower dissolved metal and certain trace concentrations than natural lakes and groundwater. In both settings, groundwater rich in dissolved elements (e.g. Al, As, Fe, Mn, Ni and PO43) flows into the gravel pit lakes where the pH and DO are high, which enhances the (co)precipitation of Fe, Mn and Al oxides that include trace elements. Metal concentrations in the Dutch lake's bottom sediments have increased over a 10 year period. Redox reactions caused by water table lowering and farmland fertilization upstream from the lake explain the metals mobilization and subsequent transport with groundwater towards the lakes. The gravel pit lakes, especially if there are many close together, influence so the cycle of water metals, nutrients as well as other trace elements of a watershed by incorporating them into biomass and bottom sediments or creating an environment where they can remain in concentrated solution.

  16. Small Eddies in Lake Superior and Their Relation to the Seasonal Thermal Front

    NASA Astrophysics Data System (ADS)

    Holt, B.; Gierach, M. M.; Matsumoto, K.; McKinney, P. J.

    2014-12-01

    Making use of the fine resolution of satellite SAR, sunglint, and thermal IR imagery, we observe small eddies during the spring and summer months in Lake Superior, which are important in lake mixing and nearshore water quality. During these months there is a thermal gradient between warmer near shore waters and colder offshore waters which enhances cyclonic coastal currents, as identified by sea surface temperature (SST) imagery for Lake Superior from the Advanced Along Track Scanning Radiometer, over the period 1995-2012. In this study, we will compare the location, diameter, rotational sense, and seasonality of identified eddies in terms of the strength of the thermal gradient and general circulation patterns within the lake to identify possible patterns of eddy formation, evolution, and dissipation.

  17. The sea lamprey--a threat to Great Lakes fisheries

    USGS Publications Warehouse

    Van Oosten, John

    1949-01-01

    SUMMARY 1. The wood mouse (Peromyscus leucopus) population in a 17-acre area of bottomland forest was live-trapped, marked and released over a 7-night period. Following the live-trapping a central 1-acre plot was snap-trapped for 35 consecutive nights. All adult animals taken in the central snap-trapped plot had previously been taken, marked, and released in the live-trapped 17-acre area. 2. Animals taken first in the central acre were those whose normal ranges overlapped or closely approached this area. After these were removed from the area the animals captured in the central acre were in general those whose normal ranges were at succeedingly greater distances. Ingress was from all directions. 3. Most of the animals taken in the central area were those with previously established nearby home ranges, not merely vagrant animals. 4. Thirty-six of the invading animals were adult males, 18 were adult females, and 22 were young juveniles recently emerged from nests. Numbers of male and female adults had been shown in the live-trapping to be approximately equal.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  19. Lake Garda, Italy

    NASA Technical Reports Server (NTRS)

    2000-01-01

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

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

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

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

  20. The influence of irrigation water on the hydrology and lake water budgets of two small arid-climate lakes in Khorezm, Uzbekistan

    USGS Publications Warehouse

    Scott, J.; Rosen, Michael R.; Saito, L.; Decker, D.L.

    2011-01-01

    Little is known regarding the origins and hydrology of hundreds of small lakes located in the western Uzbekistan province of Khorezm, Central Asia. Situated in the Aral Sea Basin, Khorezm is a productive agricultural region, growing mainly cotton, wheat, and rice. Irrigation is provided by an extensive canal network that conveys water from the Amu Darya River (AD) throughout the province. The region receives on average 10 cm/year of precipitation, yet potential evapotranspiration exceeds this amount by about 15 times. It was hypothesized that the perennial existence of the lakes of interest depends on periodic input of excess irrigation water. This hypothesis was investigated by studying two small lakes in the region, Tuyrek and Khodjababa. In June and July 2008, surface water and shallow groundwater samples were collected at these lake systems and surrounding communities and analyzed for ?2H, ?18O, and major ion hydrochemistry to determine water sources. Water table and lake surface elevations were monitored, and the local aquifer characteristics were determined through aquifer tests. These data and climate data from a Class A evaporation pan and meteorological stations were used to estimate water budgets for both lakes. Lake evaporation was found to be about 0.7 cm/day during the study period. Results confirm that the waters sampled at both lake systems and throughout central Khorezm were evaporated from AD water to varying degrees. Together, the water budgets and stable isotope and major ion hydrochemistry data suggest that without surface water input from some source (i.e. excess irrigation water), these and other Khorezm lakes with similar hydrology may decrease in volume dramatically, potentially to the point of complete desiccation.

  1. SeaWiFS Calibration and Algorithm Validation

    NASA Technical Reports Server (NTRS)

    Parada, Robert J., Jr.; Slater, Philip N.

    1996-01-01

    This is the fourth annual report on NASA grant NAGW 3543, titled 'Sea-viewing Wide Field of view Sensor (SeaWiFS) calibration and algorithm validation'. An extended field experiment was conducted at Lake Tahoe in late July 1996 that involved: experimental verification of radiative transfer computations for various viewing geometries; retrieval of an effective aerosol optical depth height; calibration of a large field of view (FOV) sensor; and an evaluation of spatial non-uniformities in surface reflectance. The investigation and development of novel methods for the calibration of field radiometers at a variety of signal levels has been continued during the past year.

  2. Life history of lake herring in Lake Superior

    USGS Publications Warehouse

    Dryer, William R.; Beil, Joseph

    1964-01-01

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

  3. Titan Mare Explorer (TiME): A Discovery Mission to Titan’s Hydrocarbon Lakes

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.; Stofan, E. R.; Lunine, J. I.; Kirk, R. L.; Mahaffy, P. R.; Bierhaus, B.; Aharonson, O.; Clark, B. C.; Kantsiper, B.; Ravine, M. A.; Waite, J. H.; Harri, A.; Griffith, C. A.; Trainer, M. G.

    2009-12-01

    The discovery of lakes in Titan’s high latitudes confirmed the expectation that liquid hydrocarbons exist on the surface of the haze-shrouded moon. The lakes fill through drainage of subsurface runoff and/or intersection with the subsurface alkanofer, providing the first evidence for an active condensable-liquid hydrological cycle on another planetary body. The unique nature of Titan’s methane cycle, along with the prebiotic chemistry and implications for habitability of Titan’s lakes, make the lakes of the highest scientific priority for in situ investigation. The Titan Mare Explorer mission is an ASRG (Advanced Stirling Radioisotope Generator)-powered mission to a lake on Titan. The mission would be the first exploration of a planetary sea beyond Earth, would demonstrate the ASRG both in deep space and a non-terrestrial atmosphere environment, and pioneer low-cost outer planet missions. The scientific objectives of the mission are to: determine the chemistry of a Titan lake to constrain Titan’s methane cycle; determine the depth of a Titan lake; characterize physical properties of liquids; determine how the local meteorology over the lakes ties to the global cycling of methane; and analyze the morphology of lake surfaces, and if possible, shorelines, in order to constrain the kinetics of liquids and better understand the origin and evolution of Titan lakes. The focused scientific goals, combined with the new ASRG technology and the unique mission design, allows for a new class of mission at much lower cost than previous outer planet exploration has required.

  4. SOLS: A lake database to monitor in the Near Real Time water level and storage variations from remote sensing data

    NASA Astrophysics Data System (ADS)

    Crétaux, J.-F.; Jelinski, W.; Calmant, S.; Kouraev, A.; Vuglinski, V.; Bergé-Nguyen, M.; Gennero, M.-C.; Nino, F.; Abarca Del Rio, R.; Cazenave, A.; Maisongrande, P.

    2011-05-01

    An accurate and continuous monitoring of lakes and inland seas is available since 1993 thanks to the satellite altimetry missions (Topex-Poseidon, GFO, ERS-2, Jason-1, Jason-2 and Envisat). Global data processing of these satellites provides temporal and spatial time series of lakes surface height with a decimetre precision on the whole Earth. The response of water level to regional hydrology is particularly marked for lakes and inland seas in semi-arid regions. A lake data centre is under development at by LEGOS (Laboratoire d'Etude en Géophysique et Océanographie Spatiale) in Toulouse, in coordination with the HYDROLARE project (Headed by SHI: State Hydrological Institute of the Russian Academy of Science). It already provides level variations for about 150 lakes and reservoirs, freely available on the web site (HYDROWEB: http://www.LEGOS.obs-mip.fr/soa/hydrologie/HYDROWEB), and surface-volume variations of about 50 big lakes are also calculated through a combination of various satellite images (Modis, Asar, Landsat, Cbers) and radar altimetry. The final objective is to achieve in 2011 a fully operating data centre based on remote sensing technique and controlled by the in situ infrastructure for the Global Terrestrial Network for Lakes (GTN-L) under the supervision of WMO (World Meteorological Organization) and GCOS (Global Climate Observing System).

  5. How the Lakes Were Formed

    NSDL National Science Digital Library

    This resource helps students to understand the geological formation of the Great Lakes and how glaciers shaped the Great Lakes basin. Students will discover that about a billion years ago, a fracture in the earth running from what is now Oklahoma to Lake Superior generated volcanic activity that almost split North America and that this geomorphic age created mountains covering the region now known as northern Wisconsin and Minnesota. They will also learn that glaciers advanced and retreated several times over the last 5 million years and that during the periods of glaciation, giant sheets of ice flowed across the land, leveling mountains and carving out massive valleys. Where the glaciers encountered more resistant bedrock in the north, only the overlying layers were removed. The site has diagrams that show the step-by-step creation of the lakes by the glaciers and also a Great Lakes system profile with text that illustrates the relative depths of the lakes and connecting waterways.

  6. Toxaphene in the Great Lakes.

    PubMed

    Swackhamer, D L; Pearson, R F; Schottler, S P

    1998-01-01

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentration, which is contrary to the pattern seen for other pollutants. The observed log particle-water partition coefficient was 4.5. Recent sediments had similar concentrations among the lakes (approx. 15 ng/g dry weight), but different homolog compositions. The log bioaccumulation factors (BAFs) normalized to lipid or organic carbon were 5.8, 6.5, 6.3, 6.7, 6.7, and 7.0 for phytoplankton, net zooplankton, Mysis, Bythotrephes, sculpin, and lake trout. These data clearly show that toxaphene biomagnifies in the foodweb. PMID:9828352

  7. The north polar lakes of Titan as observed by Cassini Radar

    NASA Astrophysics Data System (ADS)

    Mitchell, K. L.; Paillou, P.; Kirk, R. L.; Lunine, J. I.; Stofan, E. R.; Radebaugh, J.; Wall, S. D.; Hayes, A. G.; Lopes, R. M.; Stiles, B. W.; Ostro, S. J.; Lorenz, R. D.; Wood, C. A.; Cassini RADAR Team

    2007-12-01

    Over the course of a year, Cassini RADAR obtained Synthetic Aperture Radar images covering 69 percent of Titan's polar region north of 65 degrees; the region being 1.4E6 km3 in extent, greater than double the land area of the USA. We observe several hundred lakes with a range of morphological expression, including areally massive and morphologically distinctive "seas", covering ~15% of the polar region. Lakes are extremely radar dark, consistent with a lossy liquid hydrocarbon. Preliminary laboratory estimates suggest that loss tangents in the range 10E4 to 2x10E3 are reasonable, which implies that one can see through at least a few to many tens of m of liquids before the noise floor is reached, consistent with observed brightening towards many lake shores. North polar lake volumes are most likely in the 8E3 - 1.4E6 km3 range. Uncertainties will be reduced as more data, both image-based and experimental, are obtained but we can conclude with a high degree of confidence that hydrocarbon lakes on Titan are more voluminous than known terrestrial oil reserves; current estimates range from 2248 - 3896 billion barrels of oil (J. Hakes, 2000, Long Term World Oil Supply, Meeting of the Am. Ass. Pet. Geol., 18th April 2000, New Orleans, LA, http://www.eia.doe.gov/pub/oil_gas/petroleum/presentations/2000/long_term_supply.), hence 357 - 619 km3 . Small lakes often occupy steep-sided depressions, and although thermal and cryovolcanic origins cannot be completely ruled out, we are seeing growing geomorphologic evidence for dissolution chemistry, indicative of karst-like geology. The dichotomy between small lakes over slightly more than one half of the region, and seas on the other half, may be best explained by a topographic anomaly causing sub-surface flow of materials from the lakes to the seas. This may also explain observations by the Cassini ISS team (E. Turtle et al., in prep.) of a putative massive sea extending considerably further south than other observed north polar lakes.

  8. GREAT LAKES UNIVERSITY OF KISUMU INTRODUCTION

    E-print Network

    Petriu, Emil M.

    GREAT LAKES UNIVERSITY OF KISUMU INTRODUCTION The Great Lakes University of Kisumu is an off on these capacities. The Identity of the Great Lakes University of Kisumu The University is founded on Christian

  9. 27 CFR 9.128 - Seneca Lake.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Areas § 9.128 Seneca Lake. (a) Name. The name...this section is “Seneca Lake”. (b) Approved Maps...the boundary of the Seneca Lake viticultural area are 13 United States Geological Survey (USGS) topographic...

  10. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...this section is “Alexandria Lakes”. (b) Approved maps...boundary of the Alexandria Lakes viticultural area are four United States Geological Survey 1:24,000 scale topographic...1966, revised 1994. (3) Lake Miltona East, Minn.,...

  11. 27 CFR 9.128 - Seneca Lake.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Areas § 9.128 Seneca Lake. (a) Name. The name...this section is “Seneca Lake”. (b) Approved Maps...the boundary of the Seneca Lake viticultural area are 13 United States Geological Survey (USGS) topographic...

  12. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...this section is “Alexandria Lakes”. (b) Approved maps...boundary of the Alexandria Lakes viticultural area are four United States Geological Survey 1:24,000 scale topographic...1966, revised 1994. (3) Lake Miltona East, Minn.,...

  13. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...this section is “Alexandria Lakes”. (b) Approved maps...boundary of the Alexandria Lakes viticultural area are four United States Geological Survey 1:24,000 scale topographic...1966, revised 1994. (3) Lake Miltona East, Minn.,...

  14. 27 CFR 9.128 - Seneca Lake.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Areas § 9.128 Seneca Lake. (a) Name. The name...this section is “Seneca Lake”. (b) Approved Maps...the boundary of the Seneca Lake viticultural area are 13 United States Geological Survey (USGS) topographic...

  15. 27 CFR 9.128 - Seneca Lake.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Areas § 9.128 Seneca Lake. (a) Name. The name...this section is “Seneca Lake”. (b) Approved Maps...the boundary of the Seneca Lake viticultural area are 13 United States Geological Survey (USGS) topographic...

  16. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...this section is “Alexandria Lakes”. (b) Approved maps...boundary of the Alexandria Lakes viticultural area are four United States Geological Survey 1:24,000 scale topographic...1966, revised 1994. (3) Lake Miltona East, Minn.,...

  17. 27 CFR 9.177 - Alexandria Lakes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...this section is “Alexandria Lakes”. (b) Approved maps...boundary of the Alexandria Lakes viticultural area are four United States Geological Survey 1:24,000 scale topographic...1966, revised 1994. (3) Lake Miltona East, Minn.,...

  18. 27 CFR 9.128 - Seneca Lake.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Areas § 9.128 Seneca Lake. (a) Name. The name...this section is “Seneca Lake”. (b) Approved Maps...the boundary of the Seneca Lake viticultural area are 13 United States Geological Survey (USGS) topographic...

  19. Temporal Changes and Altitudinal Distribution of Aerobic Anoxygenic Phototrophs in Mountain Lakes

    PubMed Central

    ?uperová, Zuzana; Holzer, Evelyn; Salka, Ivette

    2013-01-01

    Aerobic anoxygenic phototrophs (AAPs) are bacteriochlorophyll a-containing microorganisms that use organic substrates for growth but can supplement their energy requirements with light. They have been reported from various marine and limnic environments; however, their ecology remains largely unknown. Here infrared epifluorescence microscopy was used to monitor temporal changes in AAPs in the alpine lake Gossenköllesee, located in the Tyrolean Alps, Austria. AAP abundance was low (103 cells ml?1) until mid-July and reached a maximum of ?1.3 × 105 cells ml?1 (29% of all prokaryotes) in mid-September. We compared the studied lake with other mountain lakes located across an altitudinal gradient (913 to 2,799 m above sea level). The concentration of dissolved organic carbon and water transparency seem to be the main factors influencing AAP abundance during the seasonal cycle as well as across the altitudinal gradient. While the AAP populations inhabiting the alpine lakes were composed of intensely pigmented large rods (5 to 12 ?m), the lakes below the tree line were inhabited by a variety of smaller morphotypes. Analysis of pufM diversity revealed that AAPs in Gossenköllesee were almost exclusively Sphingomonadales species, which indicates that AAP communities inhabiting alpine lakes are relatively homogeneous compared to those in low-altitude lakes. PMID:23956384

  20. Mountain lakes of Russian subarctic as markers of air pollution: Acidification, metals and paleoecology

    SciTech Connect

    Moiseenko, T.I.; Dauvalter, V.A.; Kagan, L.Y. [Institute of the North Industrial Ecology Problems (INEP), Murmansk (Russian Federation)

    1996-12-31

    The Kola Peninsula mountain lakes reflect a real situation not only of the local air pollution but also polluted transborder emissions from Europe to Arctic and they are of interest for early detection and monitoring for acidification and pollution by heavy metals. Two monitoring mountain lakes had a discrepancy by their resistance to acidification: the Chuna lake is vulnerable and the Chibiny one is not, respectively. Despite the Chuna and Chibiny lakes are close tone of the main heavy metal pollution sources of the Kola Peninsula - smelters of the Severonickel Company, local emissions very slightly affect the mountain lakes, because heavily polluted air masses do not rise in altitude. Sulfur deposition on the Chuna lake catchment is 0.4 gSm{sup -2}, Chibiny lake is 0.6 gSm{sup -2}. In comparison with area at the foot of the mountain (less than 200 m above the sea level) sulfur deposition is 1.0-1.5 gSm{sup -2}. Water quality, sediment chemistry, and diatoms in sediment cores were studied.

  1. Chemical evolution of the Salton Sea, California: Nutrient and selenium dynamics

    USGS Publications Warehouse

    Schroeder, R.A.; Orem, W.H.; Kharaka, Y.K.

    2002-01-01

    The Salton Sea is a 1000-km2 terminal lake located in the desert area of southeastern California. This saline (???44 000 mg l-1 dissolved solids) lake started as fresh water in 1905-07 by accidental flooding of the Colorado River, and it is maintained by agricultural runoff of irrigation water diverted from the Colorado River. The Salton Sea and surrounding wetlands have recently acquired substantial ecological importance because of the death of large numbers of birds and fish, and the establishment of a program to restore the health of the Sea. In this report, we present new data on the salinity and concentration of selected chemicals in the Salton Sea water, porewater and sediments, emphasizing the constituents of concern: nutrients (N and P), Se and salinity. Chemical profiles from a Salton Sea core estimated to have a sedimentation rate of 2.3 mm yr-1 show increasing concentrations of OC, N, and P in younger sediment that are believed to reflect increasing eutrophication of the lake. Porewater profiles from two locations in the Sea show that diffusion from bottom sediment is only a minor source of nutrients to the overlying water as compared to irrigation water inputs. Although loss of N and Se by microbial-mediated volatilization is possible, comparison of selected element concentrations in river inputs and water and sediments from the Salton Sea indicates that most of the N (from fertilizer) and virtually all of the Se (delivered in irrigation water from the Colorado River) discharged to the Sea still reside within its bottom sediment. Laboratory simulation on mixtures of sediment and water from the Salton Sea suggest that sediment is a potential source of N and Se to the water column under aerobic conditions. Hence, it is important that any engineered changes made to the Salton Sea for remediation or for transfer of water out of the basin do not result in remobilization of nutrients and Se from the bottom sediment into the overlying water.

  2. The Eutrophication of Lake Okeechobee

    Microsoft Academic Search

    Daniel E. Canfield Jr; Mark V. Hoyer

    1988-01-01

    Average annual total phosphorus concentrations in Lake Okeechobee increased from 0.049 mg\\/L in 1973 to 0.098 mg\\/L in 1984. The increases in total phosphorus concentrations were not correlated to external phosphorus inputs, but to changes in lake water levels. It is proposed that the flooding of marshes and exposed lake bottom primarily caused increased total phosphorus concentrations, but that the

  3. Landsat analysis of lake quality

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  4. Lake Ontario phytoplankton, September 1964

    USGS Publications Warehouse

    Ogawa, Roann E.

    1969-01-01

    Phytoplankton counts on samples collected in Lake Ontario on September 8-18, 1964, showed that green algae were the dominant plankters and diatoms were of secondary importance. The greatest abundance of phytoplankton was close to shore from Toronto, along the southern shore of the lake, and up the eastern shore to the North Channel. The open waters of Lake Ontario were characterized by low numbers of phytoplankton. The relationships among phytoplankton abundance, bottom fauna distribution, and enrichment are discussed.

  5. Great Lakes Mosaic

    NSDL National Science Digital Library

    The Canada Centre for Remote Sensing's (CCRC's Geogratis site for free online data provides this mosaic image of the Great Lakes Watershed. The mosaic is composed of 82 Landsat MSS images acquired between June 1 and September 15 from 1985 to 1987. The imagery can be downloaded via FTP or as a .zip file. Notes on data collection and processing techniques along with a list of references are also available.

  6. Glacial Lake Hides Bacteria

    NSDL National Science Digital Library

    Peplow, Mark

    2010-03-01

    This article highlights the published work of a geomicrobiology research team led by Eric Gaidos from the University of Hawaii and Brian Lanoil, from the University of California, Riverside. This group reports the identification of bacteria from an Icelandic sub-glacial lake, and how the collection and description of these microorganisms immured within glacial ice and sub-surface water serve as a model in the search for extra-terrestrial life.

  7. Angora Fire, Lake Tahoe

    NASA Technical Reports Server (NTRS)

    2007-01-01

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

  8. Lake Carl Blackwell SCIMARRONRD

    E-print Network

    Ghajar, Afshin J.

    Lake Carl Blackwell HuntCreek ClearCreek 6TH ST HWY51C NS 324 RD EW 63RD NS326RD EW 62 RD NS325RD 26 35 71 25 35 11 49 71 26 65 65 11 10 11 25 11 49 25 25 33 11 11 81 25 51 76 59 3 SOIL SURVEY 800200 Meters Web Soil Survey 1.1 National Cooperative Soil Survey 5/7/2007 Page 1 of 4 #12;MAP

  9. The microbiology and biogeochemistry of the Dead Sea

    Microsoft Academic Search

    Arie Nissenbaum

    1975-01-01

    The Dead Sea is a hypersaline water body. Its total dissolved salts content is on the average 322.6 gm\\/liter. The dominant cation is Mg (40.7 gm\\/liter), followed by Na (39.2 gm\\/liter), Ca (17 gm\\/liter) and K (7 gm\\/liter). The major anion is Cl (212 gm\\/liter), followed by Br (5 gm\\/liter); SO4 and HCO3, are very minor. The lake contains a

  10. Host-Size Selection by Parasitic Sea Lampreys

    Microsoft Academic Search

    William D. Swink

    1991-01-01

    When 171 sea lampreys Petromyzon marinus were each offered a onetime choice of one large and two small lake trout Salvelinus namaycush, the ratio of their attacks (49.1%:27.5%: 23.4%) was similar to the ratio of host surface areas (51.4%:26.3%:22.3%) in laboratory tests conducted over 9 months in 1988–1989. When the smallest offered host was 560 mm total length (TL) or

  11. Lake-levels, vegetation and climate in Central Asia during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Amosov, Mikhail

    2014-05-01

    Central Asian region is bounded in the east corner of the Greater Khingan Range and the Loess Plateau, and to the west - the Caspian Sea. This representation of region boundaries is based on classical works of A.Humboldt and V.Obruchev. Three typical features of Central Asia nature are: climate aridity, extensive inland drainage basins with numerous lakes and mountain systems with developed glaciation. Nowadays the extensive data is accumulated about lake-levels during the Last Glacial Maximum (LGM) in Central Asia. Data compilation on 20 depressions, where lakes exist now or where they existed during LGM, shows that most of them had usually higher lake-level than at present time. This regularity could be mentioned for the biggest lakes (the Aral Sea, the Balkhash, the Ysyk-Kol etc.) and for small ones that located in the mountains (Tien Shan, Pamir and Tibet). All of these lake basins get the precipitation due to westerlies. On the other hand lakes, which are located in region's east rimland (Lake Qinghai and lakes in Inner Mongolia) and get the precipitation due to summer East Asian monsoons, do not comply with the proposed regularity. During LGM these lake-levels were lower than nowadays. Another exception is Lake Manas, its lake-level was also lowered. Lake Manas is situated at the bottom of Junggar Basin. There are many small rivers, which come from the ranges and suffer the violent fluctuation in the position of its lower channel. It is possible to assume that some of its runoff did not get to Lake Manas during LGM. Mentioned facts suggest that levels of the most Central Asian lakes were higher during LGM comparing to their current situation. However, at that period vegetation was more xerophytic than now. Pollen data confirm this information for Tibet, Pamir and Tien Shan. Climate aridization of Central Asia can be proved by data about the intensity of loess accumulation during LGM. This evidence received for the east part of region (the Loess Plateau) and for its west part (the piedmonts of Tien Shan and Pamir Mountains). So it confirms a synchronous aridization in different parts of Central Asia. It was the result of amplification of winter Siberian anticyclone, weakening westerlies and East Asian summer monsoons. The observed discrepancy between vegetation conditions and lake-levels during LGM can be explained by lake-levels dependence on runoff as now from mountains, where snow and glaciers melt. Investigations in the area of Mongun Tayga (Tyva Republic in Russian Federation, Lake Hyargas Nuur basin) suggest that precipitation decreased by 30% during LGM, but at the same time snow accumulation increased due to lower temperature in mountains. Thus, special conditions were provided for climate cryoaridization, when vegetation was degraded due to lowering precipitation, but lake-levels grew due to higher runoff from mountain ranges.

  12. Tagish Lake Meteorite

    NSDL National Science Digital Library

    In January 2000, a meteorite struck the Earth in Tagish Lake, Ontario. The Tagish Lake meteorite has resurfaced in the news because recent results of mineralogic and isotopic analyses on it have revealed that it is comprised of some of the oldest matter from the solar system to be recovered and is a rare carbonaceous chondrite. This Website from the University of Western Ontario (part of a consortium for study of the meteorite with University of Calgary and NASA/JSC) is dedicated to the Tagish event and subsequent research. Brief overviews of the satellite equipment used, classification and mineralogy of the meteorite, and a .pdf-formatted reprint of the resulting paper by Brown, et al., printed in the October 13, 2000 issue of Science , are provided. Other information available includes a schematic and table of the bolide's inferred orbit, a summary of eyewitness accounts, and links to other sites featuring this impact. The recovery effort that took place on the frozen lake is recounted with accompanying photos and map (.jpeg). In addition, users can view video footage and photos of the flash, dust, and clouds formed from the meteorite (.jpeg, QuickTime).

  13. Development and implementation of an integrated program for control of sea lampreys in the St. Marys River

    USGS Publications Warehouse

    Schleen, Larry P.; Christie, Gavin C.; Heinrich, John W.; Bergstedt, Roger A.; Young, Robert J.; Morse, Terry J.; Lavis, Dennis S.; Bills, Terry D.; Johnson, James E.; Ebener, Mark P.

    2003-01-01

    The development and implementation of a strategy for control of sea lampreys (Petromyzon marinus) in the St. Marys River formed the basis for rehabilitation of lake trout (Salvelinus namaycush) and other fish in Lakes Huron and Michigan. The control strategy was implemented by the Great Lakes Fishery Commission (GLFC) upon recommendations by the interagency Sea Lamprey Integration Committee, and many managers and scientists from United States and Canada federal, state, provincial, tribal, and private institutions. Analyses of benefits vs. costs of control options and modeling of the cumulative effects on abundance of parasitic-phase sea lampreys and lake trout produced a strategy that involved an integration of control technologies that included long- and short-term measures. The long-term measures included interference with sea lamprey reproduction by the trapping and removal of spawning-phase sea lampreys from the river and the sterilization and release of the trapped male sea lampreys. The theoretical reduction of larvae produced in the river from these two combined techniques averaged almost 90% during 1997 to 1999. Lampricide treatment with granular Bayluscide of 880 ha of plots densely populated with larvae occurred during 1998, 1999, and 2001 because modeling showed the sooner parasitic-phase sea lamprey populations declined in Lake Huron the greater the improvement for restoration of lake trout during 1995 to 2015. Post-treatment assessments showed about 55% of the larvae had been removed from the river. An adaptive assessment plan predicted high probability of detection of control effects because of many available indicators. The GLFC will face several critical decisions beyond 2001, and initiated a decision analysis project to aid in those decisions.

  14. Lake Baikal Bibliography, 1989- 1999

    E-print Network

    Limnological Institute of RAS SB

    1999-01-01

    change from Central Asia. // International Project on Paleolimnology and Late Cenozoic Climate /changes and climatic events in Lake Baikal sediments. // International Project on Paleolimnology and Late Cenozoic Climate /

  15. Sea Surface Temperatures

    NSDL National Science Digital Library

    1999-10-30

    Users can search for and view sea surface temperature imagery. They may choose from the latest image, or browse archived imagery that dates back approximately two weeks. Links to other sea surface temperature datasets are included.

  16. The Dynamic Great Lakes Todd Hayden

    E-print Network

    Limburg, Karin E.

    characteristics Carlson's Trophic Status index Nutrient limitation- productivity · Limiting resource- lack, streams, rivers, sewage #12;3 Great Lakes- chemical characteristics Lake chlorophyll (µg/L) trophic class

  17. Evaluating Great Lakes Bald Eagle Nesting Habitat

    E-print Network

    for bald eagles (Haliaeetus leucocephalus) along the five Great Lakes shorelines. We developed a pattern eagle, Bayesian inference, Great Lakes, habitat modeling, Haliaeetus leuco- cephalus, nesting habitat

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

    SciTech Connect

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

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

  19. PCB concentrations and activity of sea lamprey Petromyzon marinus vary by sex

    USGS Publications Warehouse

    Madenjian, Charles P.; Johnson, Nicholas S.; Binder, Thomas R.; Rediske, Richard R.; O'Keefe, James P.

    2013-01-01

    We determined the polychlorinated biphenyl (PCB) concentrations of 40 male and 40 female adult sea lampreys Petromyzon marinus captured in the Cheboygan River, a tributary to Lake Huron, during May 2011. In addition, we performed a laboratory experiment using passive integrated transponder tags to determine whether male adult sea lampreys were more active than female adult sea lampreys. Sex had a significant effect on PCB concentration, and PCB concentration at a given level of sea lamprey condition was approximately 25 % greater in males than in females. Adjusting for the difference in condition between the sexes, males averaged a 17 % greater PCB concentration compared with females. Results from the laboratory experiment indicated that males were significantly more active than females. The observed sex difference in PCB concentrations was not due to female sea lampreys releasing eggs at spawning because the sea lamprey is semelparous, and we caught the sea lampreys before spawning. Rather, we attributed the sex difference in PCB concentrations to a greater rate of energy expenditure in males compared with females. We proposed that this greater rate of energy expenditure was likely due to greater activity. Our laboratory experiment results supported this hypothesis. A greater resting metabolic rate may also have contributed to a greater rate of energy expenditure. Our findings should eventually be applicable toward improving control of sea lamprey, a pest responsible for considerable damage to fisheries in lakes where it is not native.

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

    USGS Publications Warehouse

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

    2001-01-01

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

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

    USGS Publications Warehouse

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

    1997-01-01

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

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

    USGS Publications Warehouse

    Van Oosten, John; Eschmeyer, Paul H.

    1956-01-01

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

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

    Microsoft Academic Search

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

    1998-01-01

    Gillnet selectivity for lake trout ( Salvelinus namaycush) was estimated indirectly from catches in nets of 102-, 114-, 127-, 140-, and 152-mm stretch measure. Mesh selectivity was modeled as a nonlinear response surface that describes changes in the mean, standard deviation, and skewness of fish lengths across mesh sizes. Gillnet selectivity for lake trout was described by five parameters that

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  5. All That Unplowed Sea

    ERIC Educational Resources Information Center

    MOSAIC, 1975

    1975-01-01

    Hunting and gathering at sea may fast be approaching their productive limits. Aquaculture - farming at sea - linked to conservation represents the sea's promise. If the system works, it might prove to be the key to supplying large amounts of food and fresh water at no cost in nonrenewable energy resources. (BT)

  6. Sea ice transports in the Weddell Sea

    NASA Astrophysics Data System (ADS)

    Harms, Sabine; Fahrbach, Eberhard; Strass, Volker H.

    2001-05-01

    Time series of sea ice draft in the Weddell Sea are evaluated together with hydrographic observations, satellite passive microwave data, and ice drift for estimation of the freshwater fluxes into and out of the Weddell Sea. Ice draft is measured with moored upward looking sonars since 1990 along two transects across the Weddell Gyre. One transect, extending from the tip of the Antarctic Peninsula to Kapp Norvegia, was sampled between 1990 and 1994 and covers the flow into and out of the southern Weddell Sea. The other transect, sampled since 1996 and extending from the Antarctic continent northward along the Greenwich meridian, covers the exchange of water masses between the eastern and the western Weddell Sea. In order to relate results obtained during the different time periods, empirical relationships are established between the length of the sea ice season, derived from the satellite passive microwave data and defined as the number of days per year with the sea ice concentration exceeding 15%, and (1) the annual mean ice draft and (2) the annual mean ice volume transport. By using these empirical relationships, estimates of annual mean ice drafts and ice volume transports are derived at all mooring sites for the period February 1979 through February 1999. Wind and current force a westward ice transport in the coastal areas of the eastern Weddell Sea and a northward ice transport in the west. During the 2-year period 1991/1992 the mean ice volume export from the Weddell Sea is (50 ± 19) × 103 m3 s-1. This freshwater export is representative for a longer-term (20-year) mean and exceeds the average amount of freshwater gained by precipitation and ice shelf melt by about 19×103 m3 s-1, yielding an upper bound for the formation rate of newly ventilated bottom water in the Weddell Sea of 2.6 Sv.

  7. The Lake Ohrid SCOPSCO project

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  8. Recent Earthquakes in Yellow Sea Region and Amur Plate

    NASA Astrophysics Data System (ADS)

    Kim, W. Y.; Satake, K.

    2014-12-01

    Bird (2003) and others suggested the existence of Amur plate in northeastern Asia with its incipient plate boundary along western Honshu - Sakhalin - Stanovoy Mountains - Lake Baikal - Mongolia - Hebei Province, China - Yellow Sea - East China Sea - Nankai Trough. The seismicity along East China Sea and Yellow Sea sections of the suggested boundary is diffuse and does not delineate such boundary. However, recent earthquakes that have occurred along the Yellow Sea region during 2011-2014 show predominantly strike-slip faulting along near vertical nodal planes. These earthquakes may provide an opportunity to study details of the proposed boundaries of Amur plate. Waveform data from broadband seismographic stations in the region around Yellow Sea are analyzed in an attempt to shed light on the nature of the incipient plate boundary for the proposed Amur plate in Yellow Sea region. Regional waveform modeling and deviatoric moment tensor inversion suggest that a broad scale stress field in Yellow Sea region is ENE-WSW trending subhorizontal compressive stress, ?1, with N-S trending horizontal extensional stress, ?3. In such regional stress regime, earthquake mechanisms are predominantly vertical strike-slip faulting, but it allows some E-W normal faulting due to N-S extension. The most likely mode of deformation in Yellow Sea region appears to be right-lateral strike-slip faulting along N-S trending transform faults, and E-W trending normal faulting that accommodates a broad regional stress regime. This is a typical kinematics of rifting at rifted continental margins such as Gulf of California. We observed a broad regional seismic velocity variation along various wave propagation paths as well as indications of crustal thickness variation. Thinner crust beneath Yellow Sea region is indicated from waveform modeling which can support evolution of rifting process.

  9. Lake Michigan Lake Wide Management Plan (LaMP 2000)

    NSDL National Science Digital Library

    This new Lake Wide Management Plan from the Environmental Protection Agency's Great Lakes Program is part of a series of plans for each of the Great Lakes. It is "intended to identify the critical pollutants that affect the beneficial uses of the lake and to develop strategies, recommendations, and policy options to restore those beneficial uses." Topics covered in the report include details about the program, public involvement, ecosystem objectives, indicators and monitoring of the health of the Lake Michigan ecosystem, current status of the ecosystem, human health issues, and more. The site also offers a variety of appendices such as a glossary, a bibliography, and large, comprehensive sections on policies and regulations, as well as physical and chemical properties of pollutants.

  10. Feeding competition between larval lake whitefish and lake herring

    USGS Publications Warehouse

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

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

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

    PubMed

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

    2008-11-15

    This study considers the importance of lake trout habitat as a factor determining persistent organochlorine (OC) concentration. Lake trout is a stenothermal, cold water species and sensitive to hypoxia. Thus, factors such as lake depth, thermal stratification, and phosphorus enrichment may determine not only which lakes can support lake trout but may also influence among-lake variability in lake trout population characteristics including bioaccumulation of OCs. A survey of 23 lakes spanning much of the natural latitudinal distribution of lake trout provided a range of lake trout habitat to test the hypothesis that lake trout with greater access to littoral habitat for feeding will have lower concentrations of OCs than lake trout that are more restricted to pelagic habitat. Using the delta13C stable isotope signature in lake trout as an indicator of influence of benthic littoral feeding, we found a negative correlation between lipid-corrected delta13C and sigmaPCB concentrations supporting the hypothesis that increasing accessto littoral habitat results in lower OCs in lake trout. The prominence of mixotrophic phytoplankton in lakes with more contaminated lake trout indicated the pelagic microbial food web may exacerbate the biomagnification of OCs when lake trout are restricted to pelagic feeding. A model that predicted sigmaPCB in lake trout based on lake area and latitude (used as proximate variables for proportion of littoral versus pelagic habitat and accessibility to littoral habitat respectively) explained 73% of the variability in sigmaPCBs in lake trout in the 23 lakes surveyed. PMID:19068800

  12. Great Lakes Research Vessel Construction

    USGS Multimedia Gallery

    Two new additions to the U.S. Geological Survey Great Lakes Science Center's fleet of large research vessels are currently being constructed. The two new USGS research vessels will replace the aging vessels on lakes Erie and Ontario. They will provide safe and reliable platforms for scient...

  13. The Great Lakes Food Web.

    ERIC Educational Resources Information Center

    Baker, Marjane L.

    1997-01-01

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

  14. Great Lakes Research Vessel Construction

    USGS Multimedia Gallery

    Two new additions to the U.S. Geological Survey Great Lakes Science Center's fleet of large research vessels are currently being constructed. The two new USGS research vessels will replace the aging vessels on lakes Erie and Ontario. They will provide safe and reliable platforms for scientists, and ...

  15. Pyramid Lake Renewable Energy Project

    Microsoft Academic Search

    John Jackson

    2008-01-01

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

  16. GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY

    E-print Network

    GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY ANNUAL REPORT FY 1981 December 1981 Eugene J . Aubert and Development Environmental Research Laboratories Great Lakes Environmental Research Laboratory 2300 Washtenaw Avenue Ann Arbor, Michigan 48104 #12;NOTICE The NOAA Environmental Research Laboratories do not approve

  17. GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY

    E-print Network

    #12;GREAT LAKES ENVIRONMENTAL RESEARCH LABORATORY ANNUAL REPORT FY 1980 December I980 Eugene J of Research and Development Environmental Research Laboratories Great Lakes Environmental Research Laboratory 2300 Washtenaw Avenue Ann Arbor, Michigan 48104 #12;NOTICE The NOAA Environmental Research Laboratories

  18. An urban lake remediation experiment

    SciTech Connect

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

    1998-07-01

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

  19. Lake Tanganyika ecosystem management strategies

    Microsoft Academic Search

    Hudson H. Nkotagu

    2008-01-01

    Lake Tanganyika is a large East African rift valley system holding about 1\\/6 of the world's liquid freshwater with about 2000 species of organisms (fauna and flora), of which about 700 are endemic. The lake faces a number of threats including excess sedimentation, overfishing, pollution, habitat destruction, along with climate change. Efforts to better understand these involved an assessment of

  20. TROPHIC EQUILIBRIUM OF LAKE WASHINGTON

    EPA Science Inventory

    Sewage effluent was diverted progressively from Lake Washington during 1963-1968, and the chemical conditions changed in close relation to the amount of sewage entering. The total phosphorus content of the lake decreased rapidly to 1971 after which year it varied around a value o...