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Sample records for lake champlain sea

  1. 76 FR 12129 - Lake Champlain Sea Lamprey Control Alternatives Workgroup

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ... Fish and Wildlife Service Lake Champlain Sea Lamprey Control Alternatives Workgroup AGENCY: Fish and... (Service), announce a ] meeting of the Lake Champlain Sea Lamprey Control Alternatives Workgroup (Workgroup... and implementation of sea lamprey control techniques alternative to lampricide that are...

  2. 75 FR 82061 - Lake Champlain Sea Lamprey Control Alternatives Workgroup

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ...-1335-0000-J3] Lake Champlain Sea Lamprey Control Alternatives Workgroup AGENCY: Fish and Wildlife...), announce a meeting of the Lake Champlain Sea Lamprey Control Alternatives Workgroup (Workgroup). The... date. ADDRESSES: The meeting will be held at the Lake Champlain Basin Program/Vermont Fish and...

  3. 75 FR 54163 - Office of the Secretary: Renewal of the Lake Champlain Sea Lamprey Control Alternatives Workgroup

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-03

    ... Champlain Sea Lamprey Control Alternatives Workgroup AGENCY: Office of the Secretary, Interior. ACTION... General Services Administration, has reestablished the charter for the Lake Champlain Sea Lamprey Control... policy and technical advice on efforts to develop and implement sea lamprey control...

  4. Impacts of post-glacial lake drainage events and revised chronology of the Champlain Sea episode 13-9 ka

    USGS Publications Warehouse

    Cronin, T. M.; Manley, P.L.; Brachfeld, S.; Manley, T.O.; Willard, D.A.; Guilbault, J.-P.; Rayburn, J.A.; Thunell, R.; Berke, M.

    2008-01-01

    Lithologic, CHIRP (Compressed High Intensity Radar Pulse) sonar, paleomagnetic, stable isotopic and micropaleontological analyses of sediment cores from Lake Champlain (New York, Vermont) were used to determine the age of the post-glacial Champlain Sea marine episode, the timing of salinity changes and their relationship to freshwater discharge from mid-continent glacial lakes. Calibrated radiocarbon ages on plant material provide an improved post-glacial chronology overcoming problems from shell ages caused by carbon reservoir effects up to 1500 yr. The final drainage of glacial Lake Vermont and the inception of marine conditions occurred ∼ 13.1–12.8 ka (kiloannum, calendar years) and a sharp decrease in Champlain Sea salinity from ∼ 25 to 7–8 psu (practical salinity units) occurred approximately 11.4–11.2 ka. Reduced salinity was most likely caused by rapid freshwater inflow eastward from glacial Lake Algonquin into the Champlain Basin. The timing of inferred freshwater event coincides with the widespread climatic cooling called the Preboreal Oscillation.

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

    EPA Pesticide Factsheets

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

  6. Watershed Modeling Recommendation Report for Lake Champlain TMDL

    EPA Pesticide Factsheets

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

  7. 78 FR 14444 - Drawbridge Operation Regulation; Lake Champlain, Swanton, VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-06

    ... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Lake Champlain, Swanton... proposed rulemaking (NPRM) entitled ``Drawbridge Operation Regulation; Lake Champlain, Swanton, VT'' in the... follows: Sec. 117.993 Lake Champlain. * * * * * (c) The draw of the New England Central Railroad...

  8. Constraints on Lake Agassiz discharge through the late-glacial Champlain Sea (St. Lawrence Lowlands, Canada) using salinity proxies and an estuarine circulation model

    USGS Publications Warehouse

    Katz, B.; Najjar, R.G.; Cronin, T.; Rayburn, J.; Mann, M.E.

    2011-01-01

    During the last deglaciation, abrupt freshwater discharge events from proglacial lakes in North America, such as glacial Lake Agassiz, are believed to have drained into the North Atlantic Ocean, causing large shifts in climate by weakening the formation of North Atlantic Deep Water and decreasing ocean heat transport to high northern latitudes. These discharges were caused by changes in lake drainage outlets, but the duration, magnitude and routing of discharge events, factors which govern the climatic response to freshwater forcing, are poorly known. Abrupt discharges, called floods, are typically assumed to last months to a year, whereas more gradual discharges, called routing events, occur over centuries. Here we use estuarine modeling to evaluate freshwater discharge from Lake Agassiz and other North American proglacial lakes into the North Atlantic Ocean through the St. Lawrence estuary around 11.5 ka BP, the onset of the Preboreal oscillation (PBO). Faunal and isotopic proxy data from the Champlain Sea, a semi-isolated, marine-brackish water body that occupied the St. Lawrence and Champlain Valleys from 13 to 9 ka, indicate salinity fell about 7-8 (range of 4-11) around 11.5 ka. Model results suggest that minimum (1600 km3) and maximum (9500 km3) estimates of plausible flood volumes determined from Lake Agassiz paleoshorelines would produce the proxy-reconstructed salinity decrease if the floods lasted <1 day to 5 months and 1 month to 2 years, respectively. In addition, Champlain Sea salinity responds very quickly to the initiation (within days) and cessation (within weeks) of flooding events. These results support the hypothesis that a glacial lake flood, rather than a sustained routing event, discharged through the St. Lawrence Estuary during the PBO. ?? 2011 Elsevier Ltd.

  9. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... vessels of the United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on... hours notice is given by calling the number posted at the bridge. (3) The draw shall open on signal...

  10. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... vessels of the United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on... hours notice is given by calling the number posted at the bridge. (3) The draw shall open on signal...

  11. 33 CFR 117.797 - Lake Champlain.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on the hour and the... the SR78 bridge, mile 105.9 across the entrance to Missisquoi Bay between Alburg Tongue and Hog...

  12. 33 CFR 117.797 - Lake Champlain.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on the hour and the... the SR78 bridge, mile 105.9 across the entrance to Missisquoi Bay between Alburg Tongue and Hog...

  13. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vessels of the United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on... hours notice is given by calling the number posted at the bridge. (3) The draw shall open on signal...

  14. 33 CFR 117.797 - Lake Champlain.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain, between South Hero Island and North Hero Island, shall operate as follows: (1) The draw shall open on signal on the hour and the... the SR78 bridge, mile 105.9 across the entrance to Missisquoi Bay between Alburg Tongue and Hog...

  15. 33 CFR 110.136 - Lake Champlain, NY and VT.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lake Champlain, NY and VT. 110... ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington Harbor, Vt. (1) The waters bounded by a line connecting the following points: Latitude Longtitude...

  16. 33 CFR 110.136 - Lake Champlain, NY and VT.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lake Champlain, NY and VT. 110... ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington Harbor, Vt. (1) The waters bounded by a line connecting the following points: Latitude Longtitude...

  17. 33 CFR 110.136 - Lake Champlain, NY and VT.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lake Champlain, NY and VT. 110... ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington Harbor, Vt. (1) The waters bounded by a line connecting the following points: Latitude Longtitude...

  18. 33 CFR 110.136 - Lake Champlain, NY and VT.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lake Champlain, NY and VT. 110... ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington Harbor, Vt. (1) The waters bounded by a line connecting the following points: Latitude Longtitude...

  19. 33 CFR 110.136 - Lake Champlain, NY and VT.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lake Champlain, NY and VT. 110... ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington Harbor, Vt. (1) The waters bounded by a line connecting the following points: Latitude Longtitude...

  20. SWAT Model Configuration, Calibration and Validation for Lake Champlain Basin

    EPA Pesticide Factsheets

    The Soil and Water Assessment Tool (SWAT) model was used to develop phosphorus loading estimates for sources in the Lake Champlain Basin. This document describes the model setup and parameterization, and presents calibration results.

  1. Lake Champlain TMDL Modeling Quality Assurance Project Plan

    EPA Pesticide Factsheets

    This document presents the quality assurance project plan for providing support to US EPA Region 1 in revising the Lake Champlain Total Maximum Daily Load, under Contract Number EP-C-08-004, Task Order 80.

  2. The evolution and distribution of methane in Lake Champlain sediments

    SciTech Connect

    Thibodeau, P.M. . Dept. of Geology)

    1993-03-01

    Regions of Lake Champlain sediments are acoustically impenetrable to the energy emitted from high resolution, low energy sub-bottom seismic profiling apparatus. This anomolous behavior is caused by the presence of interstitial methane gas which absorbs the wave energy and thus prevents the formation of well-defined seismic boundaries. Through gas chromatographic and carbon isotope analyses, the methane gas contained in the recent sediments of Lake Champlain has been demonstrated to be biogenic in origin. The production of biogenic methane occurs as a result of a series of coupled oxidation-reduction reactions occurring within the upper two meters beneath the sediment-water interface.

  3. 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.

  4. Micropaleontological Record of Post-glacial History in Lake Champlain and Adjacent Regions: Implications for Glacial Lake Drainage and Abrupt Climate Events

    NASA Astrophysics Data System (ADS)

    Cronin, T. M.; Manley, P. L.; Guilbault, J.; Berke, M.; Rayburn, J. A.; Franzi, D. A.; Knuepfer, P. L.

    2005-12-01

    Post-glacial lacustrine and marine sediments of the Lake Champlain region range from 20 to >50 meters in thickness presenting an opportunity to assess the timing of North American glacial lake drainage at multidecadal timescales and evaluate its effect on North Atlantic salinity and abrupt climate events 13.5 to 10 kyr B.P. High-resolution analysis of foraminifera and ostracodes from cores taken onshore in the Plattsburgh, N.Y. vicinity and southern Quebec and offshore in southern Lake Champlain reveal complex changes in salinity during and after the transition from pro-glacial Lake Vermont (Lake Candona in Canada) to marine sedimentation in the Champlain Sea. The microfaunal sequence (bottom to top) includes: non-marine ostracodes ( Candona) in lacustrine varves, foraminiferal assemblages (common Cassidulina reniforme), another interval of Candona-bearing sediments (sometimes containing foraminifera), and, finally, sediments from the main phase of the Champlain sea episode containing diverse foraminiferal and marine ostracode assemblages. A decrease in salinity during the Champlain Sea is also in evidence from the shift in dominance of distinct variants of Elphidium in the deep basin. The marine episode ended with a progressive salinity decrease and the formation of Lake Champlain about 10 kyr B.P. Observed salinity changes could be caused by catastrophic fresh-water influx from large glacial lakes west of the Lake Champlain region, meltwater from the retreating Laurentide Ice Sheet margin, diminished influx of marine water from the St. Lawrence due to changes in the position of the ice sheet margin and isostatic adjustment, or a combination of factors. The ages of these events were determined by estimating the reservoir effect on radiocarbon dates on marine shells through comparison with AMS dates on plant material and palynology, and shed light on the hypothesis that glacial lake discharges catalyzed abrupt climate events.

  5. ERTS-1 imagery of the Lake Champlain region: A first look

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (Principal Investigator); Henson, E. B.; Olson, J.; Wagner, W. P.

    1972-01-01

    The author has identified the following significant results. First-look analysis of RBV imagery of Lake Champlain and adjacent areas provided the following information on land and water resources: (1) location and shape of islands over 200 meters at narrowest part; (2) location of manmade structures at least 10 meters across; (3) location of shoreline; (4) identification of algal blooms and major turbidity boundary; (5) identification of lake bottom features in sandy, shallow areas; (6) identification of major lake shore wetland and floodplain wetlands; (7) location of major streams; (8) identification of ice marginal deposits of major proportions and former shorelines of Champlain Sea; (9) identification of wooded areas, open land, and built-up areas.

  6. 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

  7. Environmental study of ERTS-1 imagery: Lake Champlain and Vermont

    NASA Technical Reports Server (NTRS)

    Lind, A. O.; Henson, E. B.; Pelton, J. O.

    1973-01-01

    Environmental concerns of the State of Vermont currently being stressed include water quality in Lake Champlain and a state-wide land use and capability plan. Significant results obtained from ERTS-1 relate directly to the above concerns. Industrial water pollution and turbidity in Lake Champlain have been identified and mapped and the ERTS pollution data will be used in the developing court suit which Vermont has initiated against the polluters. ERTS imagery has also provided a foundation for updating and revising land use inventories. Major classes of land use have been identified and mapped, and substantial progress has been made toward the mapping of such land use divisions as crop and forest type, and wetlands.

  8. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lake Champlain, N.Y. and Vt. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.8 Lake Champlain, N.Y. and Vt. (a) Ticonderoga...) Shelburne, Vt. An area shoreward of a line bearing 142° from the eastern point of Collymer Pt. to Allen...

  9. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lake Champlain, N.Y. and Vt. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.8 Lake Champlain, N.Y. and Vt. (a) Ticonderoga...) Shelburne, Vt. An area shoreward of a line bearing 142° from the eastern point of Collymer Pt. to Allen...

  10. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lake Champlain, N.Y. and Vt. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.8 Lake Champlain, N.Y. and Vt. (a) Ticonderoga...) Shelburne, Vt. An area shoreward of a line bearing 142° from the eastern point of Collymer Pt. to Allen...

  11. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lake Champlain, N.Y. and Vt. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.8 Lake Champlain, N.Y. and Vt. (a) Ticonderoga...) Shelburne, Vt. An area shoreward of a line bearing 142° from the eastern point of Collymer Pt. to Allen...

  12. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lake Champlain, N.Y. and Vt. 110... ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.8 Lake Champlain, N.Y. and Vt. (a) Ticonderoga...) Shelburne, Vt. An area shoreward of a line bearing 142° from the eastern point of Collymer Pt. to Allen...

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

    USGS Publications Warehouse

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

    2013-01-01

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

  14. A Relationship Between Phosphate Levels in Lake Champlain Tributaries and Soil Type and Particulate Size

    NASA Astrophysics Data System (ADS)

    Larose, R.; Lee, S.; Lane, T.

    2014-12-01

    Lake Champlain is a large natural fresh water lake. It forms the western boundary of Vermont and drains over half of the state. It is bordered by the state of New York on its western side and drains to the north into Quebec, Canada. Lake Champlain is the source of fresh drinking water for over quarter of a million people and provides for the livelihoods and recreational opportunities of many well beyond its borders. The health of this lake is important. During the summermonth's algae blooms plague the lake. These unsightlygrowths, which affect other aquatic organisms, are the result of excess phosphate flowing into the lake from major tributaries.Exploring the relationship between soil type and particulate size to phosphate levels in tributaries to the Lake Champlain basin sheds insight on potential sources of phosphate from the Lake Champlain watershed into the lake and may point topossible mitigation efforts. Total Phosphate levels and Total Suspended Solids were measured in second and third order streams in the Lake Champlain Basin over a three-year period. These streamsfeed into the Missisquoi River and Winooski Rivers, whichflow into Lake Champlain. Soil was sampled along transects from uplands areas through the riparian corridor to the edge of the streams. These samples were then classified using the Unified Soil Classification System (USCS) and an analysis of particle size was conducted.In general there is a correlation between higher levels of phosphate and smaller particulate size.

  15. August 2015 Proposed Total Maximum Daily Load Document and Appendices for Vermont Segments of Lake Champlain

    EPA Pesticide Factsheets

    These documents provide allocations of phosphorus loads to Lake Champlain to meet water quality criteria, describe basis for allocation for future growth, & describe how implementation measures were simulated to determine that allocations can be achieved

  16. A Relationship Between Microbial Activity in Soils and Phosphate Levels in Tributaries to Lake Champlain

    NASA Astrophysics Data System (ADS)

    Larose, R.; Lee, S.; Lane, T.

    2015-12-01

    Lake Champlain is a large natural freshwater lake. It forms the western boundary of Vermont and drains over half of the state. It is bordered by the state of New York on its western side and drains to the north into Quebec, Canada. Lake Champlain is the source of fresh drinking water for over quarter of a million people and provides for the livelihoods and recreational opportunities of many well beyond its borders. The health of this lake is important. During the summer month's algae blooms plague the lake. These unsightly growths, which affect other aquatic organisms, are the result of excess phosphate flowing into the lake from many sources. Examining whether there is a relationship between microbial activity in the soils bordering tributaries to Lake Champlain and phosphate levels in those tributaries sheds insight into the origins and paths by which phosphate moves into Lake Champlain. Understanding the how phosphate moves into the water system may assist in mitigation efforts.Total Phosphate levels and Total Suspended Solids were measured in second and third order streams in the Lake Champlain Basin over a three-year period. In addition microbial activity was measured within the toe, bank and upland riparian zone areas of these streams during the summer months. In general in areas showing greater microbial activity in the soil(s) there were increased levels of phosphate in the streams.

  17. Pollution monitoring in Lake Champlain using ERTS-1 imagery

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (Principal Investigator); Henson, E. B.

    1973-01-01

    The author has identified the following significant results. Band 4 imagery of April 7 and 25 show contrasting pollution effects due to seasonal and discharge variations. The pollution plume emanating from the International Paper Co. mill just north of Fort Ticonderoga was first detected on October 10 ERTS-1 imagery and now has been documented during spring high lake level conditions. The plume was observed extending further to the north and east than under low water conditions of October 10. This northward extension reflects a stronger northward current flow expected in the turbid southern leg of Lake Champlain. The extensive plume of April 25 represents full plant operation while the April 5 scene shows some plume traces directly over the submerged diffuser, discharge pipe representing minimal discharge during weekend plant operation. The ERTS-1 documentation will be used in developing a model of plume behavior under varying environmental conditions and will hopefully serve to assist in a major resource decision pending at U.S. Supreme Court level.

  18. Flood-inundation maps for Lake Champlain in Vermont and in northern Clinton County, New York

    USGS Publications Warehouse

    Flynn, Robert H.; Hayes, Laura

    2016-06-30

    Digital flood-inundation maps for an approximately100-mile length of Lake Champlain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York were created by the U.S. Geological Survey (USGS) in cooperation with the International Joint Commission (IJC). The flood-inundationmaps, which can be accessed through the International Joint Commission (IJC) Web site at http://www.ijc.org/en_/, depict estimates of the areal extent flooding correspondingto selected water levels (stages) at the USGS lake gage on the Richelieu River (Lake Champlain) at Rouses Point, N.Y. (station number 04295000). In this study, wind and seiche effects (standing oscillating wave with a long wavelength) were not taken into account and the flood-inundation mapsreflect 11 stages (elevations) for Lake Champlain that are static for the study length of the lake. Near-real-time stages at this lake gage, and others on Lake Champlain, may be obtained on the Internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service Advanced Hydrologic Prediction Service at http:/water.weather.gov/ahps/, which also forecasts flood hydrographs at the Richelieu River (Lake Champlain) at Rouses Point.Static flood boundary extents were determined for LakeChamplain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York using recently acquired (2013–2014) lidar (light detection and ranging) and may be referenced to any of the five USGS lake gages on Lake Champlain. Of these five lakgages, USGS lake gage 04295000, Richelieu River (Lake Champlain) at Rouses Point, N.Y., is the only USGS lake gage that is also a National Weather Service prediction location. Flood boundary extents for the Lake Champlain static flood-inundation map corresponding to the May 201 flood(103.2 feet [ft], National Geodetic Vertical Datum [NGVD] 29) were evaluated by comparing these boundary

  19. SWAT modeling of Critical Source Area for Runoff and Phosphorus losses: Lake Champlain Basin, VT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lake Champlain, located between Vermont, New York, and Quebec, exhibits eutrophication due to continuing phosphorus (P) inputs mainly from upstream nonpoint source areas. To address the Lake's eutrophication problem and as part of total maximum daily load (TMDL) requirements, a state-level P reducti...

  20. Determination of critical source areas for phosphorous losses: Lake Champlain Basin, Vermont

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lake Champlain, located between Vermont, New York, and Quebec, exhibits eutrophication due to continuing phosphorus (P) inputs mainly from upstream nonpoint source areas. To address the Lake's eutrophication problem and as part of total maximum daily load (TMDL) requirements, a state-level P reducti...

  1. Small-scale lacustrine drifts in Lake Champlain, Vermont

    USGS Publications Warehouse

    Manley, Patricia L.; Manley, T.O.; Hayo, Kathryn; Cronin, Thomas

    2012-01-01

    High resolution CHIRP (Compressed High Intensity Radar Pulse) seismic profiles reveal the presence of two lacustrine sediment drifts located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments. Drift B sits on a basement high while Drift A is built on a trough-filling acoustically-transparent sediment unit inferred to be a mass-transport event. These drifts are oriented approximately north–south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of upslope asymmetric mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was investigated using Acoustic Doppler Current Profilers (ADCPs) located across Drift A. Sediment cores were taken at the crest and at the edges of the Drift A and were dated. Drift source, deposition, and evolution show that these drifts are formed by a water column shear with the highest deposition occurring along its crest and western flank and began developing circa 8700–8800 year BP.

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

    PubMed

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

    2012-02-01

    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.

  3. Assessment of nutrient distributions in Lake Champlain using satellite remote sensing.

    PubMed

    Isenstein, Elizabeth M; Park, Mi-Hyun

    2014-09-01

    The introduction of nutrients to lakes causing eutrophic conditions is a major problem around the world. Proper monitoring and modeling are important to effectively manage eutrophication in lake waters. The goal is to develop remote sensing models for nutrients, total phosphorus and total nitrogen, in Lake Champlain. The remote sensing models were created using multivariate linear regression with the unique band combinations of Landsat Enhanced Thematic Mapper Plus (ETM+) imagery based on the empirical relationship with the field observations. The resulting models successfully showed nutrient distributions in the most eutrophic part of Lake Champlain, Missisquoi Bay, with reasonable adjusted coefficient of determination values (R(2)=0.81 and 0.75 for total phosphorus and total nitrogen, respectively). The results show the feasibility and the utility of satellite imagery to detect spatial distributions of lake water quality constituents, which can be used to better understand nutrient distributions in Lake Champlain. This approach can be applicable to other lakes experiencing eutrophication assisting decision making when implementing Best Management Practices and other mitigation techniques to lakes.

  4. 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.

  5. Groundwater quality in the Lake Champlain Basin, New York, 2009

    USGS Publications Warehouse

    Nystrom, Elizabeth A.

    2011-01-01

    Water was sampled from 20 production and domestic wells from August through November 2009 to characterize groundwater quality in the Lake Champlain Basin in New York. Of the 20 wells sampled, 8 were completed in sand and gravel, and 12 were completed in bedrock. The samples were collected and processed by standard U.S. Geological Survey procedures and were analyzed for 147 physiochemical properties and constituents, including major ions, nutrients, trace elements, pesticides, volatile organic compounds (VOCs), radionuclides, and indicator bacteria. Water quality in the study area is generally good, but concentrations of some constituents equaled or exceeded current or proposed Federal or New York State drinking-water standards; these were color (1 sample), pH (3 samples), sodium (3 samples), total dissolved solids (4 samples), iron (4 samples), manganese (3 samples), gross alpha radioactivity (1 sample), radon-222 (10 samples), and bacteria (5 samples). The pH of all samples was typically neutral or slightly basic (median 7.1); the median water temperature was 9.7°C. The ions with the highest median concentrations were bicarbonate [median 158 milligrams per liter (mg/L)] and calcium (median 45.5 mg/L). Groundwater in the study area is soft to very hard, but more samples were hard or very hard (121 mg/L or more as CaCO3) than were moderately hard or soft (120 mg/L or less as CaCO3); the median hardness was 180 mg/L as CaCO3. The maximum concentration of nitrate plus nitrite was 3.79 mg/L as nitrogen, which did not exceed established drinking-water standards for nitrate plus nitrite (10 mg/L as nitrogen). The trace elements with the highest median concentrations were strontium (median 202 micrograms per liter [μg/L]), and iron (median 55 μg/L in unfiltered water). Six pesticides and pesticide degradates, including atrazine, fipronil, disulfoton, prometon, and two pesticide degradates, CIAT and desulfinylfipronil, were detected among five samples at concentrations

  6. Groundwater quality in the Lake Champlain and Susquehanna River basins, New York, 2014

    USGS Publications Warehouse

    Scott, Tia-Marie; Nystrom, Elizabeth A.; Reddy, James E.

    2016-11-04

    In a study conducted by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation, groundwater samples were collected from 6 production wells and 7 domestic wells in the Lake Champlain Basin and from 11 production wells and 9 domestic wells in the Susquehanna River Basin in New York. All samples were collected from June through December 2014 to characterize groundwater quality in these basins. The samples were collected and processed using standard procedures of the U.S. Geological Survey and were analyzed for 148 physiochemical properties and constituents, including dissolved gases, major ions, nutrients, trace elements, pesticides, volatile organic compounds, radionuclides, and indicator bacteria.The Lake Champlain Basin study area covers the 3,050 square miles of the basin in northeastern New York; the remaining part of the basin is in Vermont and Canada. Of the 13 wells sampled in the Lake Champlain Basin, 6 are completed in sand and gravel, and 7 are completed in bedrock. Groundwater in the Lake Champlain Basin was generally of good quality, although properties and concentrations of some constituents— fluoride, iron, manganese, dissolved solids, sodium, radon-222, total coliform bacteria, fecal coliform bacteria, and Escherichia coli bacteria—sometimes equaled or exceeded primary, secondary, or proposed drinking-water standards. The constituent most frequently detected in concentrations exceeding drinking-water standards (5 of 13 samples) was radon-222.The Susquehanna River Basin study area covers the entire 4,522 square miles of the basin in south-central New York; the remaining part of the basin is in Pennsylvania. Of the 20 wells sampled in the Susquehanna River Basin, 11 are completed in sand and gravel, and 9 are completed in bedrock. Groundwater in the Susquehanna River Basin was generally of good quality, although properties and concentrations of some constituents—pH, chloride, sodium, dissolved

  7. The age, growth, and feeding habits of the whitefish Coregonus clupeaformis (Mitchell), of Lake Champlain

    USGS Publications Warehouse

    Van Oosten, John; Deason, Hilary J.

    1939-01-01

    This study is based on 120 whitefish collected in northern Lake Champlain (Missisquoi Bay) in 1930 and on 175 whitefish taken in southern Lake Champlain in 1931. Since the whitefish population had not been exploited commercially after 1912 in United States waters and after 1915 in Canadian waters, its study should be of interest in showing the characteristics of a population practically untouched by man. Data have been presented on length frequencies, age composition, growth, coefficient of condition, sex ratio, standard length-total length relationship, and feeding habits. The data indicated that the Missisquoi Bay population was disturbed (probably by the early fall seining of 1930) before our samples were taken so that the original length distributions no longer existed. The southern Lake Champlain material, however, showed a consistency which indicated that the population had not been exploited to any extensive degree, if at all. When the northern population was compared with the southern the former was found to differ from the latter in the following respects, which differences pointed to some disturbance of the northern stock in the lake 1. By possession of lower modes and smaller grand averages of length. 2. By absence of very old individuals. 3. By absence of a series of equally abundant age groups or, in other words, by the presence of a decided dominance of one or two age groups. 4. By a radical disagreement between the sexes in their age-frequency distribution. 5. By a disagreement between the sexes with respect to maximum lengths attained. All of the differences between the two collections could, however, not be attributed to exploitation. The following characteristics indicated the presence of two distinct populations in the lake 1. Presence of a spawning ground at each end of the lake. 2. Differences in calculated lengths and increments of length (growth rates). 3. Differences in the actual lengths and weights of corresponding age groups at capture. 4

  8. Native rainbow smelt and nonnative alewife distribution related to temperature and light gradients in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Sullivan, Patrick J.; Pientka, Bernard

    2012-01-01

    Alewife (Alosa pseudoharengus) recently became established in Lake Champlain and may compete with native rainbow smelt (Osmerus mordax) for food or consume larval rainbow smelt. The strength of this effect depends partly on the spatial and temporal overlap of different age groups of the two species; therefore, we need a better understanding of factors affecting alewife and rainbow smelt distributions in Lake Champlain. We used hydroacoustics, trawls, and gill nets to document vertical fish distribution, and recorded environmental data during 16 day–night surveys over two years. Temperature, temperature change, and light were all predictors of adult and age-0 rainbow smelt distribution, and temperature and light were predictors of age-0 alewives' distribution (based on GAMM models evaluated with AIC). Adult alewives were 5–30 m shallower and age-0 alewives were 2–15 m shallower than their rainbow smelt counterparts. Adult rainbow smelt distribution overlapped with age-0 rainbow smelt and age-0 alewives near the thermocline (10–25 m), whereas adult alewives were shallower (0–6 m) and overlapped with age-0 alewives and rainbow smelt in the epilimnion. Adult rainbow smelt were in water < 10–12 °C, whereas age-0 rainbow smelt were in 10–20 °C, and adult and age-0 alewives were in 15–22 °C water. Predicting these species distributions is necessary for quantifying the strength of predatory and competitive interactions between alewife and rainbow smelt, as well as between alewife and other fish species in Lake Champlain.

  9. 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.

  10. 33 CFR 165.T01-0176 - Regulated Navigation Area; Lake Champlain Bridge Construction, Crown Point, New York and Chimney...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of the regulated navigation area (RNA). All navigable waters on Lake Champlain 300 yards to the north... conditions apply within this RNA: (1) No vessel may operate at a speed in excess of five knots. (2) All.... (2) The COTP may temporarily suspend all vessel traffic through the RNA, temporarily...

  11. 33 CFR 165.T01-0176 - Regulated Navigation Area; Lake Champlain Bridge Construction, Crown Point, New York and Chimney...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of the regulated navigation area (RNA). All navigable waters on Lake Champlain 300 yards to the north... conditions apply within this RNA: (1) No vessel may operate at a speed in excess of five knots. (2) All.... (2) The COTP may temporarily suspend all vessel traffic through the RNA, temporarily...

  12. EPA and State of Vermont Announce Public Meetings to Discuss Final Draft Plan to Restore Lake Champlain

    EPA Pesticide Factsheets

    The U.S. EPA and the State of Vermont are holding a series of public meetings in August to discuss new pollution reduction targets - often referred to as a TMDL - to prevent pollution from flowing into Lake Champlain and its tributaries.

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

    SciTech Connect

    Saylor, J.; Miller, J. ); Manley, T.O.; Manley, P.L. . Geology Dept.)

    1993-03-01

    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. The ADCP measurement range covered 74% of the water depth at the Valcour Island site and 49% at Thompson's Point site. The deepest measurement level at the Valcour Island site was 9 m above the lake floor. Two phenomena causing intense bottom currents at Valcour Island were identified in the data sets. One occurred during the relatively weak density stratification of the early summer period. It was caused by a downwelled thermocline at Valcour which was associated with impulses of northward-directed wind stress. On three occasions the wind stress was large enough to propel essentially all hypolimnion water south of Valcour Island. After these downwellings the lower layer returned as a steeply-faced internal surge with high-speed, turbulent flow at its leading edge. The second process forcing high-speed bottom currents was related to large-amplitude internal seiches that dominated Lake Champlain's main basin during September and October. Amplitudes of the seiches approached several tens of meters; their persistence suggests near-resonant wind forcing as a generating mechanism. Currents at the deepest measurement level exceeded 30 cm/s over duration's of 12 or more hours. Periods of the internal seiches were observed to vary with the intensity of stratification and with seasonal thermocline depth as predicted by first principles governing internal wave propagation.

  14. National Dam Safety Program. Lake Flower Dam, Inventory Number NY-707. Lake Champlain River Basin. Franklin County, New York. Phase I Inspection Report,

    DTIC Science & Technology

    1980-08-01

    AD-A091 596 NEW YORK STATE DE!PT OF ENVIRONMENTAL CONSERVATION ALBANY F/B 13/13 NATIONAL OAM SAFETY PROGRAM. LAKE FLOWER DAM, INVENTORY NUMBER --ETC...Safety Program Franklin County Visual Inspeton Saranae River Hydrology, Structural Stability Lake Flower Dam -. LABSTRACT (otbue a reverse eft It...LAKE CHAMPLAIN RIVER BASIN LAKE FLOWER DAM FRANKLIN COUNTY NEW YORK INVENTORY N2 NY 707 P/ 6 ,HA_ j E SPECTION 8EPORM NATIONAL PAM AFETY PROGRAM w, -v

  15. Network global navigation satellite system surveys to harmonize American and Canadian datum for the Lake Champlain Basin

    USGS Publications Warehouse

    Flynn, Robert H.; Rydlund, Jr., Paul H.; Martin, Daniel J.

    2016-03-08

    Lake-gage water-surface elevations determined during the 3 days of surveys were converted to water-surface elevations referenced to the North American Vertical Datum of 1988 by using calculated offsets and historical water-surface elevations. In this report, an “offset” refers to the adjustment that needs to be applied to published data from a particular gage to produce elevation data referenced to the North American Vertical Datum of 1988. Offsets presented in this report can be used in the evaluation of water-surface elevations in a common datum for Lake Champlain and the Richelieu River. In addition, the water-level data referenced to the common datum (as determined from the offsets) may be used to calibrate flow models and support future modeling studies developed for Lake Champlain and the Richelieu River.

  16. New England from Boston to Lake Champlain and up to southern Main from STS-58

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This photograph includes much of the heart of New England, stretching from Boston and Boston Harbor (lower left) across New Hampshire and Vermont to Lake Champlain (upper left), and up to southern Maine (Portland is just off the photo at right center). North of Boston flows the Merrimack River (which forms part of the state boundary between Massachuesetts and New Hampshire). It is delineated by the small industrial towns (Concord, Manchester, Nashua, Lowell) which grew up on its banks. The White Mountains of New Hampshire are seen near the center, and Mt. Washington (6,288 feet) is capped with snow. Fort Sam Houston is contained within the northeast quadrant of the city, Brooks Air Force Base lies at the southeastern corner, and Lackland and Kelly Air Force Bases are within the suburban fringe to the southwest. San Antonio International Airport can be seen at the foot of the escarpment in the northern part of the city.

  17. Growth rates of rainbow smelt in Lake Champlain: Effects of density and diet

    USGS Publications Warehouse

    Stritzel, Thomson J.L.; Parrish, D.L.; Parker-Stetter, S. L.; Rudstam, L. G.; Sullivan, P.J.

    2011-01-01

    Stritzel Thomson JL, Parrish DL, Parker-Stetter SL, Rudstam LG, Sullivan PJ. Growth rates of rainbow smelt in Lake Champlain: effects of density and diet. Ecology of Freshwater Fish 2010. ?? 2010 John Wiley & Sons A/S Abstract- We estimated the densities of rainbow smelt (Osmerus mordax) using hydroacoustics and obtained specimens for diet analysis and groundtruthed acoustics data from mid-water trawl sampling in four areas of Lake Champlain, USA-Canada. Densities of rainbow smelt cohorts alternated during the 2-year study; age-0 rainbow smelt were very abundant in 2001 (up to 6fish per m2) and age-1 and older were abundant (up to 1.2fish per m2) in 2002. Growth rates and densities varied among areas and years. We used model selection on eight area-year-specific variables to investigate biologically plausible predictors of rainbow smelt growth rates. The best supported model of growth rates of age-0 smelt indicated a negative relationship with age-0 density, likely associated with intraspecific competition for zooplankton. The next best-fit model had age-1 density as a predictor of age-0 growth. The best supported models (N=4) of growth rates of age-1 fish indicated a positive relationship with availability of age-0 smelt and resulting levels of cannibalism. Other plausible models were contained variants of these parameters. Cannibalistic rainbow smelt consumed younger conspecifics that were up to 53% of their length. Prediction of population dynamics for rainbow smelt requires an understanding of the relationship between density and growth as age-0 fish outgrow their main predators (adult smelt) by autumn in years with fast growth rates, but not in years with slow growth rates. ?? 2011 John Wiley & Sons A/S.

  18. The R/V Folger a Floating Laboratory: Teaching Marine Science Skills on Lake Champlain (Invited)

    NASA Astrophysics Data System (ADS)

    Manley, P.; Manley, T.

    2013-12-01

    Undergraduate senior work has been required at Middlebury College as far back as 1960's and hands-on experiential learning was and still is the mode for our geology courses. The history of Middlebury College having a research vessel started in the 1970's when Dave Folger started the marine component of our curriculum and obtained the first Middlebury College's research vessel - a coast guard rescue surf boat (Bruno Schmidt). The second Middlebury College research vessel, the R/V Baldwin was purchased in 1985 and was used exclusively in a river-like setting due to its open cockpit and minimal research equipment. In 1990, Middlebury College received a grant from NSF-MRI to upgrade the vessel, to a then state-of the-art small oceanographic vessel including new equipment (CTD, side-scan sonar, ROV, met station, coring devices, computers and navigation). Middlebury College contributed monies to enclose the wheelhouse, install safer diesel engines, as well as a winch and an A-frame to haul in equipment. Over 600+ students used the Baldwin in a variety of geology courses; mainly Oceanography and Marine Geology. In 2010, Middlebury College received an NSF -ARRA grant (American Recovery and Reinvestment Act) to replace the ailing R/V Baldwin with a floating state-of-the art laboratory with the specific goals of increasing 1) access to lake research for Middlebury faculty and students in the biological, chemical, and environmental sciences, 2) the scope of lake research by reducing transit times over this 100km long lake, 3) stability for broad-lake research, 4) improve and expand research capabilities on Lake Champlain, 5) the carrying capacity (both equipment and people), and 6) instructional capability and overnight capabilities. The newly built R/V Folger is a sophisticated research vessel with advanced capabilities that provides a greater capacity to the research infrastructure on Lake Champlain, enhancing interdisciplinary inquiry not only for Middlebury College, but

  19. Late Wisconsinan glacial, lacustrine and marine stratigraphy in the Champlain Valley, New York and Vermont

    SciTech Connect

    Franzi, D.A. . Center for Earth and Environmental Science); Hunt, A.S. . Dept. of Geology)

    1993-03-01

    The stratigraphy of late-glacial, and postglacial deposits and landforms in the Champlain Lowland is interpreted from high-resolution (3.5 khz transducer) acoustical profiling and piston core analysis of sediments beneath Lake Champlain in conjunction with detailed morphologic sequence mapping of surficial deposits. The sediments of Lake Champlain have been grouped by acoustic, lithologic, and biostratigraphic criteria into three stratigraphic units that were deposited successively into Lake Vermont, the Champlain Sea, and Lake Champlain. The maximum thickness of unconsolidated sediment is known to exceed 200 meters locally. Biostratigraphic subdivision of these units using pollen, diatoms, ostracodes, and foraminifera provides further definition of late-glacial and postglacial events in the region and indicates that transitional environments occurred as conditions changed from proglacial lake to marine estuary to freshwater lake. The stratigraphy of surficial deposits records proglacial lake sequences in the Champlain Valley and its tributaries. Interbasinal correlation of the tributary proglacial lake sequences and reconstructed ice marginal positions, is consistent with a model of generally synchronous, northward recession controlled primarily by backwasting of active continental ice lobes. Minor asynchroneity of retreat rates may be attributed to local differences in subglacial topography and changes in proglacial lake level, both of which may affect calving rates. Northward ice recession of the Champlain Lobe allowed successive inundation of tributary valleys by Lake Vermont. Elevations of deltaic sandplains reveal at least three distinct lake levels in the northwestern Champlain Valley. The highest level corresponds to the Coveville Stage while the lower two represent levels of the Fort Ann Stage.

  20. Distribution of pollutants from a new paper plant in southern Lake Champlain, Vermont and New York

    USGS Publications Warehouse

    Mason, D.L.; Folger, D.W.; Haupt, R.S.; McGirr, R.R.; Hoyt, W.H.

    1977-01-01

    From November of 1973 to May of 1974, 15 arrays of sediment traps were placed along 33 km of southern Lake Champlain to sample the distribution of effluent from a large paper plant located on the western shore which had commenced operation in 1971. In the arrays located near the effluent diffuser pipeline as much as 2.3 cm of sediment accumulated, whereas elsewhere in the lake less than 1 cm accumulated. In the area of accelerated accumulation, sediments contained high concentrations of several components used in or derived from paper manufacturing. Values for kaolinite, expressed as the ratio of kaolinite to chlorite, for example, were as high as 1.4, anatase (TiO2) concentrations were as high as 0.8%, organic carbon 8.7%, and phosphorus 254 ??g/g; all were more abundant than in sediments collected in traps to the south or north. In surficial bottom sediments collected near each array organic carbon and phosphorus were also higher (4.2% and 127 ??g/g respectively) near the diffuser than elsewhere. Thus, the new plant after three years of production measurably affected the composition of suspended sediment and surficial bottom sediment despite the construction and use of extensive facilities to reduce the flow of pollutants to the lake. ?? 1977 Springer-Verlag New York Inc.

  1. A Multiscale Mapping Assessment of Lake Champlain Cyanobacterial Harmful Algal Blooms

    PubMed Central

    Torbick, Nathan; Corbiere, Megan

    2015-01-01

    Lake Champlain has bays undergoing chronic cyanobacterial harmful algal blooms that pose a public health threat. Monitoring and assessment tools need to be developed to support risk decision making and to gain a thorough understanding of bloom scales and intensities. In this research application, Landsat 8 Operational Land Imager (OLI), Rapid Eye, and Proba Compact High Resolution Imaging Spectrometer (CHRIS) images were obtained while a corresponding field campaign collected in situ measurements of water quality. Models including empirical band ratio regressions were applied to map chlorophyll-a and phycocyanin concentrations; all sensors performed well with R2 and root-mean-square error (RMSE) ranging from 0.76 to 0.88 and 0.42 to 1.51, respectively. The outcomes showed spatial patterns across the lake with problematic bays having phycocyanin concentrations >25 µg/L. An alert status metric tuned to the current monitoring protocol was generated using modeled water quality to illustrate how the remote sensing tools can inform a public health monitoring system. Among the sensors utilized in this study, Landsat 8 OLI holds the most promise for providing exposure information across a wide area given the resolutions, systematic observation strategy and free cost. PMID:26389930

  2. Application of ERTS-1 imagery in the Vermont-New York dispute over pollution of Lake Champlain

    NASA Technical Reports Server (NTRS)

    Lind, A. O. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. ERTS-1 imagery and a composite map derived from ERTS-1 imagery were presented as evidence in a U.S. Supreme Court case involving the pollution of an interstate water body (Lake Champlain). A pollution problem generated by a large paper mill forms the basis of the suit (Vermont vs. International Paper Co. and State of New York) and ERTS-1 imagery shows the effluent pattern on the lake surface as extending into Vermont during three different times.

  3. 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.

  4. Sediment quality in Burlington Harbor, Lake Champlain, U.S.A.

    USGS Publications Warehouse

    Lacey, E.M.; King, J.W.; Quinn, J.G.; Mecray, E.L.; Appleby, P.G.; Hunt, A.S.

    2001-01-01

    Surface samples and cores were collected in 1993 from the Burlington Harbor region of Lake Champlain. Sediment samples were analyzed for trace metals (cadmium, copper, lead, nickel, silver and zinc), simultaneously extracted metal/acid volatile sulfide (SEM-AVS), grain size, nutrients (carbon and nitrogen) and organic contaminants (polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)). The concentrations of cadmium, copper, silver and zinc from the partial sediment digestion of the surface samples correlated well with each other (r2 > 0.60) indicating that either a common process, or group of processes determined the sediment concentrations of these metals. In an analysis of the spatial distribution of the trace metals and PAHs, high surficial concentrations were present in the southern portion of the Harbor. The trace metal trend was strengthened when the concentrations were normalized by grain size. A sewage treatment plant outfall discharge was present in the southeastern portion of the Harbor at the time of this study and is the major source of trace metal and PAH contamination. Evaluation of sediment cores provides a proxy record of historical trace metal and organic inputs. The peak accumulation rate for copper, cadmium, lead, and zinc was in the late 1960s and the peak silver accumulation rate was later. The greatest accumulation of trace metals occurred in the late 1960s after discharges from the STP began. Subsequent declines in trace metal concentrations may be attributed to increased water and air regulations. The potential toxicity of trace metals and organic contaminants was predicted by comparing contaminant concentrations to benchmark concentrations and potential trace metal bioavailability was predicted with SEM-AVS results. Surface sample results indicate lead, silver, ???PAHs and ???PCBs are potentially toxic and/or bioavailable. These predictions were supported by studies of biota in the Burlington Harbor watershed. There

  5. Hydroacoustic separation of rainbow smelt (Osmerus mordax) age groups in Lake Champlain

    USGS Publications Warehouse

    Parker, Stetter S.L.; Rudstam, L. G.; Stritzel, Thomson J.L.; Parrish, D.L.

    2006-01-01

    Separate assessment of young-of-year (YOY) and yearling-and-older (YAO) fish is desirable from both ecological and management perspectives. Acoustic assessments provide information on fish population size structure in the target strength (TS) distribution, but interpretation of TS distributions must be done carefully, as single age groups can produce multiple TS modes. We assessed the ability of in situ TS distributions to identify Lake Champlain rainbow smelt (Osmerus mordax) age groups in June, July, and September of 2001 using mobile and stationary surveys, knowledge of vertical distribution preferences, and predicted TS from trawl catches. YAO rainbow smelt (93-179 mm total length) had wide TS distributions between -60 and -35 dB in all 3 months with two modes at approximately -50 and -40 dB. Most stationary survey single-fish tracks attributed to YAO had targets in both TS modes and a wide TS range often over 15 dB. Between June and September, YOY rainbow smelt TS increased, but single-fish tracks were unimodal, and the TS range was smaller (6 dB). Overlap in TS attributed to YOY and YAO increased from no overlap in June (YOY TS -76 to -61 dB, 15-25 mm) to moderate overlap in July (-76 to -50 dB, 25-63 mm) to considerable overlap in September (-68 to -45 dB, 33-80 mm). In June and July, the TS distribution changed abruptly at the thermocline, indicating almost complete separation of the two groups. A more gradual TS transition was evident in September, indicating substantial overlap between YOY and YAO. Separate estimates can be obtained in September by decomposing TS overlap into components attributed to YOY and YAO rainbow smelt. However, this decomposition introduces additional uncertainty and an assessment in July or possibly August is preferable to obtain separate abundance estimates of YOY and YAO. ?? 2006 Elsevier B.V. All rights reserved.

  6. Paper plant effluent revisited-southern Lake Champlain, Vermont and New York

    USGS Publications Warehouse

    Haupt, R.S.; Folger, D.W.

    1993-01-01

    We used geologic and geochemical techniques to document the change with time of the distribution and concentration of contaminated bottom sediments in southern Lake Champlain near an International Paper Company plant. Our work, initiated in 1972, was expanded on behalf of Vermont citizens in a class-action suit against the International Paper Company. To update our 1972-1973 results, we collected nine cores in 1988 upstream and downstream from the paper plant effluent diffuser. Water content, volatile solids, organic carbon, and three ratios, Al/Si, Cl/Si, and S/Si, in addition to megascopic and microscopic observations, were evaluated to identify and trace the distribution of effluent and to measure the thickness of sediment affected by or containing components of effluent. Analyses were carried out on samples from the cores as well as from effluent collected directly from the plant's waste treatment facility. In 1973, two years after the plant opened, we cored near the diffuser; sediment contaminated with effluent was 4.5 cm thick. In 1988, in the same area, sediment contaminated with effluent was 17 cm thick. In 15 years, water content increased from 72 to 85 percent, volatile solids from 7 to 20 percent, and organic carbon from 2 to 12 percent. Cl/Si and S/Si were high only near the diffuser and were zero elsewhere. In the area of the diffuser, contaminated sediment appears to be accumulating at a rate of about 1 cm/yr. At a control location 22 km upstream (south) from the plant, the top, poorly consoli-dated layer was only 1 cm or less thick both in 1973 and in 1988. The class-action suit was settled in favor of the plaintiffs for $5 million. ?? 1993 Springer-Verlag.

  7. Ground-water quality in the Lake Champlain basin, New York, 2004

    USGS Publications Warehouse

    Nystrom, Elizabeth A.

    2006-01-01

    Water samples were collected from 11 public-supply wells and 11 private domestic wells in the Lake Champlain basin in New York during the fall of 2004 to characterize the chemical quality of ground water. Wells were selected for sampling based on location and focused on areas of greatest ground-water use. Samples were analyzed for 219 physical properties and constituents, including inorganic compounds, nutrients, metals, radionuclides, pesticides and pesticide degradates, volatile organic compounds, and bacteria. Sixty-eight constituents were detected at concentrations above laboratory reporting levels. The cation and anion with the highest median concentration were calcium (34.8 mg/L) bicarbonate (134 mg/L), respectively. The predominant nutrient was nitrate, which was detected in 14 (64 percent) of the 22 samples. The two metals with the highest median concentrations were iron (175 ?g/L) and strontium (124 ?g/L); concentrations of iron, manganese, aluminum, and zinc exceeded U.S. Environmental Protection Agency secondary drinking-water standards in one or more samples. Radon concentrations were less than 1,000 picocuries per liter (pCi/L) in most samples, but concentrations as high as 6,900 pCi/L were detected and, in eight samples, exceeded the U.S. Environmental Protection Agency proposed maximum contaminant level (300 pCi/L) for radon. The most frequently detected pesticides were degradates of the broadleaf herbicides metolachlor, alachlor, and atrazine. Volatile organic compounds were detected in only three samples; those that were detected typically were fuel oxygenates, such as methyl tert-butyl ether. Coliform bacteria were detected in four samples, two of which also tested positive for E. coli.

  8. Wastewater effluent, combined sewer overflows, and other sources of organic compounds to Lake Champlain

    USGS Publications Warehouse

    Phillips, P.; Chalmers, A.

    2009-01-01

    Some sources of organic wastewater compounds (OWCs) to streams, lakes, and estuaries, including wastewater-treatment-plant effluent, have been well documented, but other sources, particularly wet-weather discharges from combined-sewer-overflow (CSO) and urban runoff, may also be major sources of OWCs. Samples of wastewater-treatment-plant (WWTP) effluent, CSO effluent, urban streams, large rivers, a reference (undeveloped) stream, and Lake Champlain were collected from March to August 2006. The highest concentrations of many OWCs associated with wastewater were in WWTP-effluent samples, but high concentrations of some OWCs in samples of CSO effluent and storm runoff from urban streams subject to leaky sewer pipes or CSOs were also detected. Total concentrations and numbers of compounds detected differed substantially among sampling sites. The highest total OWC concentrations (10-100 ??g/l) were in samples of WWTP and CSO effluent. Total OWC concentrations in samples from urban streams ranged from 0.1 to 10 ??g/l, and urban stream-stormflow samples had higher concentrations than baseflow samples because of contributions of OWCs from CSOs and leaking sewer pipes. The relations between OWC concentrations in WWTP-effluent and those in CSO effluent and urban streams varied with the degree to which the compound is removed through normal wastewater treatment. Concentrations of compounds that are highly removed during normal wastewater treatment [including caffeine, Tris(2-butoxyethyl)phosphate, and cholesterol] were generally similar to or higher in CSO effluent than in WWTP effluent (and ranged from around 1 to over 10 ??g/l) because CSO effluent is untreated, and were higher in urban-stream stormflow samples than in baseflow samples as a result of CSO discharge and leakage from near-surface sources during storms. Concentrations of compounds that are poorly removed during treatment, by contrast, are higher in WWTP effluent than in CSO, due to dilution. Results indicate

  9. Interactions between hatch dates, growth rates, and mortality of Age-0 native Rainbow Smelt and nonnative Alewife in Lake Champlain

    USGS Publications Warehouse

    Parrish, Donna; Simonin, Paul W.; Rudstam, Lars G.; Pientka, Bernard; Sullivan, Patrick J.

    2016-01-01

    Timing of hatch in fish populations can be critical for first-year survival and, therefore, year-class strength and subsequent species interactions. We compared hatch timing, growth rates, and subsequent mortality of age-0 Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus, two common open-water fish species of northern North America. In our study site, Lake Champlain, Rainbow Smelt hatched (beginning May 26) almost a month earlier than Alewives (June 20). Abundance in the sampling area was highest in July for age-0 Rainbow Smelt and August for age-0 Alewives. Late-hatching individuals of both species grew faster than those hatching earlier (0.6 mm/d versus 0.4 for Rainbow Smelt; 0.7 mm/d versus 0.6 for Alewives). Mean mortality rate during the first 45 d of life was 3.4%/d for age-0 Rainbow Smelt and was 5.5%/d for age-0 Alewives. Alewife mortality rates did not differ with hatch timing but daily mortality rates of Rainbow Smelt were highest for early-hatching fish. Cannibalism is probably the primary mortality source for age-0 Rainbow Smelt in this lake. Therefore, hatching earlier may not be advantageous because the overlap of adult and age-0 Rainbow Smelt is highest earlier in the season. However, Alewives, first documented in Lake Champlain in 2003, may increase the mortality of age-0 Rainbow Smelt in the summer, which should favor selection for earlier hatching.

  10. Historical trace metal accumulation in the sediments of an urbanized region of the Lake Champlain watershed, Burlington, Vermont

    USGS Publications Warehouse

    Mecray, E.L.; King, J.W.; Appleby, P.G.; Hunt, A.S.

    2001-01-01

    This study documents the history of pollution inputs in the Burlington region of Lake Champlain, Vermont using measurements of anthropogenic metals (Cu, Zn, Cr, Pb, Cd, and Ag) in four age-dated sediment cores. Sediments record a history of contamination in a region and can be used to assess the changing threat to biota over time and to evaluate the effectiveness of discharge regulations on anthropogenic inputs. Grain size, magnetic susceptibility, radiometric dating and pollen stratigraphy were combined with trace metal data to provide an assessment of the history of contamination over the last 350 yr in the Burlington region of Lake Champlain. Magnetic susceptibility was initially used to identify land-use history for each site because it is a proxy indicator of soil erosion. Historical trends in metal inputs in the Burlington region from the seventeenth through the twentieth centuries are reflected in downcore variations in metal concentrations and accumulation rates. Metal concentrations increase above background values in the early to mid nineteenth century. The metal input rate to the sediments increases around 1920 and maximum concentrations and accumulation rates are observed in the late 1960s. Decreases in concentration and accumulation rate between 1970 and the present are observed, for most metals. The observed trends are primarily a function of variations in anthropogenic inputs and not variations in sediment grain size. Grain size data were used to remove texture variations from the metal profiles and results show trends in the anthropogenic metal signals remain. Radiometric dating and pollen stratigraphy provide well-constrained dates for the sediments thereby allowing the metal profiles to be interpreted in terms of land-use history.This study documents the history of pollution inputs in the Burlington region of Lake Champlain, Vermont using measurements of anthropogenic metals (Cu, Zn, Cr, Pb, Cd, and Ag) in four age-dated sediment cores. Sediments

  11. Use of flow-normalization to evaluate nutrient concentration and flux changes in Lake Champlain tributaries, 1990-2009

    USGS Publications Warehouse

    Medalie, Laura; Hirsch, Robert M.; Archfield, Stacey A.

    2012-01-01

    The U.S. Geological Survey evaluated 20 years of total phosphorus (P) and total nitrogen (N) concentration data for 18 Lake Champlain tributaries using a new statistical method based on weighted regressions to estimate daily concentration and flux histories based on discharge, season, and trend as explanatory variables. The use of all the streamflow discharge values for a given date in the record, in a process called "flow-normalization," removed the year-to-year variation due to streamflow and generated a smooth time series from which trends were calculated. This approach to data analysis can be of great value to evaluations of the success of restoration efforts because it filters out the large random fluctuations in the flux that are due to the temporal variability in streamflow. Results for the full 20 years of record showed a mixture of upward and downward trends for concentrations and yields of P and N. When the record was broken into two 10-year periods, for many tributaries, the more recent period showed a reversal in N from upward to downward trends and a similar reversal or reduction in magnitude of upward trends for P. Some measures of P and N concentrations and yields appear to be related to intensity of agricultural activities, point-source loads of P, or population density. Total flow-normalized P flux aggregated from the monitored tributaries showed a decrease of 30 metric tons per year from 1991 to 2009, which is about 15% of the targeted reduction established by the operational management plan for the Lake Champlain Basin.

  12. 76 FR 43698 - Lake Champlain Sea Lamprey Control Alternatives Workgroup

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ... technically feasible, cost effective, and environmentally safe. The primary objective of the meeting will be... Wildlife Resources Office, on potential for using Genetically Modified Organism (GMO) technology to...

  13. Building Adaptive Capacity with the Delphi Method and Mediated Modeling for Water Quality and Climate Change Adaptation in Lake Champlain Basin

    NASA Astrophysics Data System (ADS)

    Coleman, S.; Hurley, S.; Koliba, C.; Zia, A.; Exler, S.

    2014-12-01

    Eutrophication and nutrient pollution of surface waters occur within complex governance, social, hydrologic and biophysical basin contexts. The pervasive and perennial nutrient pollution in Lake Champlain Basin, despite decades of efforts, exemplifies problems found across the world's surface waters. Stakeholders with diverse values, interests, and forms of explicit and tacit knowledge determine water quality impacts through land use, agricultural and water resource decisions. Uncertainty, ambiguity and dynamic feedback further complicate the ability to promote the continual provision of water quality and ecosystem services. Adaptive management of water resources and land use requires mechanisms to allow for learning and integration of new information over time. The transdisciplinary Research on Adaptation to Climate Change (RACC) team is working to build regional adaptive capacity in Lake Champlain Basin while studying and integrating governance, land use, hydrological, and biophysical systems to evaluate implications for adaptive management. The RACC team has engaged stakeholders through mediated modeling workshops, online forums, surveys, focus groups and interviews. In March 2014, CSS2CC.org, an interactive online forum to source and identify adaptive interventions from a group of stakeholders across sectors was launched. The forum, based on the Delphi Method, brings forward the collective wisdom of stakeholders and experts to identify potential interventions and governance designs in response to scientific uncertainty and ambiguity surrounding the effectiveness of any strategy, climate change impacts, and the social and natural systems governing water quality and eutrophication. A Mediated Modeling Workshop followed the forum in May 2014, where participants refined and identified plausible interventions under different governance, policy and resource scenarios. Results from the online forum and workshop can identify emerging consensus across scales and sectors

  14. High-water marks from flooding in Lake Champlain from April through June 2011 and Tropical Storm Irene in August 2011 in Vermont

    USGS Publications Warehouse

    Medalie, Laura; Olson, S.A.

    2013-01-01

    The U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency, identified high-water marks after two floods in Vermont during 2011. Following a snowy winter, new monthly precipitation records were set in Burlington, Vermont, in April and May 2011, causing extensive flooding from April through June. The spring 2011 flooding resulted in a new record for stage (103.27 feet, referenced to the National Geodetic Vertical Datum of 1929) at the Lake Champlain at Burlington, Vt., gaging station (04294500). During August 28 and 29, 2011, tropical storm Irene delivered rainfall totals of 3 to more than 7 inches throughout Vermont, which resulted in extensive flooding and new streamflow records at nine streamgaging stations. Four presidential declarations of disaster were made following the 2011 flood events in Vermont. Thirty-nine high-water marks were identified and flagged to mark the highest levels of Lake Champlain from the May 2011 flooding, and 1,138 high-water marks were identified and flagged along Vermont rivers after flooding from tropical storm Irene in August 2011. Seventy-four percent of the high-water marks that were flagged were later found and surveyed to the North American Vertical Datum of 1988.

  15. 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.

  16. Sources of fine particulate species in ambient air over Lake Champlain Basin, VT

    SciTech Connect

    Ning Gao; Amy E. Gildemeister; Kira Krumhansl; Katherine Lafferty; Philip K. Hopke; Eugene Kim; Richard L. Poirot

    2006-11-15

    This study is a part of an ongoing investigation of the types and locations of emission sources that contribute fine particulate air contaminants to Underhill, VT. The air quality monitoring data used for this study are from the Interagency Monitoring of Protected Visual Environments network for the period of 2001-2003 for the Underhill site. The main source-receptor modeling techniques used are the positive matrix factorization (PMF) and potential source contribution function (PSCF). This new study is intended as a comparison to a previous study of the 1988-1995 Underhill data that successfully revealed a total of 11 types of emission sources with significant contributions to this rural site. This new study has identified a total of nine sources: nitrate-rich secondary aerosol, wood smoke, East Coast oil combustion, automobile emission, metal working, soil/dust, sulfur-rich aerosol type I, sulfur-rich aerosol type II, and sea salt/road salt. Furthermore, the mass contributions from the PMF identified sources that correspond with sampling days with either good or poor visibility were analyzed to seek possible correlations. It has been shown that sulfur-rich aerosol type I, nitrate aerosol, and automobile emission are the most important contributors to visibility degradation. Soil/dust and sea salt/road salt also have an added effect. 38 refs., 17 figs., 2 tabs.

  17. Conceptual models and sustainable groundwater resource indicators as transfer tools to stakeholders of the Lake Champlain transboundary aquifer

    NASA Astrophysics Data System (ADS)

    Lefebvre, René; Rivard, Christine; Carrier, Marc-André; Parent, Michel; Laurencelle, Marc; Beaudry, Châtelaine; Martin, Alex; Bleser, Joshua; Lavoie, Roxane; Bourque, Édith; Ouellet, Michel

    2016-04-01

    Regional aquifer assessments produce a wealth of scientific and technical information that is essential for the sound management of groundwater resources. However, regional water stakeholders are not generally groundwater specialists and cannot be expected to readily handle specialized hydrogeological maps and data. Without efficient information transfer, groundwater resources cannot be adequately considered in water governance by watershed organizations and in land-use planning by regional municipalities. This presentation provides an overview of the efforts undertaken to transfer information as part of a four-year regional aquifer assessment in the transboundary Canada-USA Champlain Lake watershed, with an emphasis on the southern Quebec part. This project was part of both the provincial aquifer assessment program (Programme d'acquisition des connaissances sur les eaux souterraines, PACES) of the Quebec Environment Ministry and the National inventory of regional key aquifers of Natural Resources Canada. In Quebec, the study area extends over 9 000 km2 and includes three major watersheds and 106 municipalities with 792 000 inhabitants. Five distinct hydrogeological contexts were defined based on bedrock geology and hydrogeological conditions: St. Lawrence Lowlands (North and South), Appalachian Piedmont, Appalachian Uplands, and Monteregian Hills. Extensive fieldwork filled knowledge and spatial data gaps identified during the compilation of existing data. To illustrate hydrogeological contexts, two conceptual models of different areas were developed. These conceptual models reflect three aspects of aquifer conditions: geological context, groundwater dynamics and groundwater quality. The first representation of the conceptual model presents the geological context including typical surficial geology units as well as major bedrock geology units (including faults and dykes). The second representation shows schematic groundwater flow paths, relative well yields of

  18. Concentration, flux, and trend estimates with uncertainty for nutrients, chloride, and total suspended solids in tributaries of Lake Champlain, 1990–2014

    USGS Publications Warehouse

    Medalie, Laura

    2016-12-20

    The U.S. Geological Survey, in cooperation with the New England Interstate Water Pollution Control Commission and the Vermont Department of Environmental Conservation, estimated daily and 9-month concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids from 1990 (or first available date) through 2014 for 18 tributaries of Lake Champlain. Estimates of concentration and flux, provided separately in Medalie (2016), were made by using the Weighted Regressions on Time, Discharge, and Season (WRTDS) regression model and update previously published WRTDS model results with recent data. Assessment of progress towards meeting phosphorus-reduction goals outlined in the Lake Champlain management plan relies on annual estimates of phosphorus flux. The percent change in annual concentration and flux is provided for two time periods. The R package EGRETci was used to estimate the uncertainty of the trend estimate. Differences in model specification and function between this study and previous studies that used WRTDS to estimate concentration and flux using data from Lake Champlain tributaries are described. Winter data were too sparse and nonrepresentative to use for estimates of concentration and flux but were sufficient for estimating the percentage of total annual flux over the period of record. Median winter-to-annual fractions ranged between 21 percent for total suspended solids and 27 percent for dissolved phosphorus. The winter contribution was largest for all constituents from the Mettawee River and smallest from the Ausable River. For the full record (1991 through 2014 for total and dissolved phosphorus and chloride and 1993 through 2014 for nitrogen and total suspended solids), 6 tributaries had decreasing trends in concentrations of total phosphorus, and 12 had increasing trends; concentrations of dissolved phosphorus decreased in 6 and increased in 8 tributaries; fluxes of total phosphorus decreased in 5 and

  19. Assessment of the spatial extent and height of flooding in Lake Champlain during May 2011, using satellite remote sensing and ground-based information

    USGS Publications Warehouse

    Bjerklie, David M.; Trombley, Thomas J.; Olson, Scott A.

    2014-01-01

    Landsat 5 and moderate resolution imaging spectro-radiometer satellite imagery were used to map the area of inundation of Lake Champlain, which forms part of the border between New York and Vermont, during May 2011. During this month, the lake’s water levels were record high values not observed in the previous 150 years. Lake inundation area determined from the satellite imagery is correlated with lake stage measured at three U.S. Geological Survey lake level gages to provide estimates of lake area at different lake levels (stage/area rating) and also compared with the levels of the high-water marks (HWMs) located on the Vermont side of the lake. The rating developed from the imagery shows a somewhat different relation than a similar stage/area rating developed from a medium-resolution digital elevation model (DEM) of the region. According to the rating derived from the imagery, the lake surface area during the peak lake level increased by about 17 percent above the average or “normal” lake level. By using a comparable rating developed from the DEM, the increase above average is estimated to be about 12 percent. The northern part of the lake (north of Burlington) showed the largest amount of flooding. Based on intersecting the inundation maps with the medium-resolution DEM, lake levels were not uniform around the lake. This is also evident from the lake level gage measurements and HWMs. The gage data indicate differences up to 0.5 feet between the northern and southern end of the lake. Additionally, the gage data show day-to-day and intradaily variation of the same range (0.5 foot). The high-water mark observations show differences up to 2 feet around the lake, with the highest level generally along the south- and west-facing shorelines. The data suggest that during most of May 2011, water levels were slightly higher and less variable in the northern part of the lake. These phenomena may be caused by wind effects as well as proximity to major river inputs to

  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. The Lakes and Seas of Titan

    NASA Astrophysics Data System (ADS)

    Hayes, Alexander G.

    2016-06-01

    Analogous to Earth's water cycle, Titan's methane-based hydrologic cycle supports standing bodies of liquid and drives processes that result in common morphologic features including dunes, channels, lakes, and seas. Like lakes on Earth and early Mars, Titan's lakes and seas preserve a record of its climate and surface evolution. Unlike on Earth, the volume of liquid exposed on Titan's surface is only a small fraction of the atmospheric reservoir. The volume and bulk composition of the seas can constrain the age and nature of atmospheric methane, as well as its interaction with surface reservoirs. Similarly, the morphology of lacustrine basins chronicles the history of the polar landscape over multiple temporal and spatial scales. The distribution of trace species, such as noble gases and higher-order hydrocarbons and nitriles, can address Titan's origin and the potential for both prebiotic and biotic processes. Accordingly, Titan's lakes and seas represent a compelling target for exploration.

  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

  3. Concentrations and Loads of Nutrients and Suspended Sediments in Englesby Brook and Little Otter Creek, Lake Champlain Basin, Vermont, 2000-2005

    USGS Publications Warehouse

    Medalie, Laura

    2007-01-01

    The effectiveness of best-management practices (BMPs) in improving water quality in Lake Champlain tributaries was evaluated from 2000 through 2005 on the basis of analysis of data collected on concentrations of total phosphorus and suspended sediment in Englesby Brook, an urban stream in Burlington, and Little Otter Creek, an agricultural stream in Ferrisburg. Data also were collected on concentrations of total nitrogen in the Englesby Brook watershed. In the winter of 2001-2002, one of three planned structural BMPs was installed in the urban watershed. At approximately the same time, a set of barnyard BMPs was installed in the agricultural watershed; however, the other planned BMPs, which included streambank fencing and nutrient management, were not implemented within the study period. At Englesby Brook, concentrations of phosphorus ranged from 0.024 to 0.3 milligrams per liter (mg/L) during base-flow and from 0.032 to 11.8 mg/L during high-flow conditions. Concentrations of suspended sediment ranged from 3 to 189 mg/L during base-flow and from 5 to 6,880 mg/L during high-flow conditions. An assessment of the effectiveness of an urban BMP was made by comparing concentrations and loads of phosphorus and suspended sediment before and after a golf-course irrigation pond in the Englesby Brook watershed was retrofitted with the objective of reducing sediment transport. Results from a modified paired watershed study design showed that the BMP reduced concentrations of phosphorus and suspended sediment during high-flow events - when average streamflow was greater than 3 cubic feet per second. While construction of the BMP did not reduce storm loads of phosphorus or suspended sediment, an evaluation of changes in slope of double-mass curves showing cumulative monthly streamflow plotted against cumulative monthly loads indicated a possible reduction in cumulative loads of phosphorus and suspended sediment after BMP construction. Results from the Little Otter Creek

  4. National Dam Safety Program. Lake Placid Village Dam. (Inventory Number NY 781), Lake Champlain River Basin, Essex County, New York. Phase I Inspection Report,

    DTIC Science & Technology

    1980-09-16

    Village of Lake Placid, Town of North Elba , Essex County, New York. c. Size Classification The maximum height of the dam is approximately 19 feet. The...certain assumptions, based on experience and existing data were used in this analysis and in the determination of the dam’s spillway capacity to pass...Day: Year 5. pparenc use - I. Fish & Wildlife Management 4. Power 2. Recreation 5. Farm * 3. Water Supply 6. No Apparent Use 6. li I. Earth with Aux

  5. Stable isotope evidence for glacial lake drainage through the St. Lawrence Estuary, eastern Canada, ~13.1-12.9 ka

    USGS Publications Warehouse

    Cronin, T. M.; Rayburn, J.A.; Guilbault, J.-P.; Thunell, R.; Franzi, D.A.

    2012-01-01

    Postglacial varved and rhythmically-laminated clays deposited during the transition from glacial Lake Vermont (LV) to the Champlain Sea (CS) record hydrological changes in the Champlain-St. Lawrence Valley (CSLV) at the onset of the Younger Dryas ∼13.1–12.9 ka linked to glacial lake drainage events. Oxygen isotope (δ18O) records of three species of benthic foraminifera (Cassidulina reniforme, Haynesina orbiculare, Islandiella helenae) from six sediment cores and the freshwater ostracode Candona from one core were studied. Results show six large isotope excursions (∼0.5 to >2‰) in C. reniforme δ18O values, five excursions in H. orbiculare (<0.5 to ∼1.8‰), and five smaller changes in I. helenae (<0.5‰). δ18O values in Candona show a 1.5–2‰ increase in the same interval. These isotopic excursions in co-occurring marine and freshwater species in varve-like sediments indicate complex hydrological changes in the earliest Champlain Sea, including brief (sub-annual) periods of complete freshening. One hypothesis to explain these results is that multiple abrupt freshwater influx events caused surface-to-bottom freshening of the Champlain Sea over days to weeks. The most likely source of freshwater would have been drainage of the Morehead Phase of glacial Lake Agassiz, perhaps in a series of floods, ultimately draining out the St. Lawrence Estuary.

  6. Fisheries Education: From the Great Lakes to the Sea.

    ERIC Educational Resources Information Center

    Fortner, Rosanne; Mayer, Victor J.

    1980-01-01

    Described are investigations related to fisheries education developed by the Ohio Sea Grant Education Office as a part of a series of Oceanic Education Activities for Great Lake Schools. The investigations discussed are "Yellow Perch in Lake Erie," which concerns fisheries management, and "It's Everyone's Sea: Or Is It," which…

  7. 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%.Key words: lake trout, sea lamprey predation, abundance, Lake Michigan

  8. Sea lamprey mark type, marking rate, and parasite-host relationships for lake trout and other species in Lake Ontario

    USGS Publications Warehouse

    Lantry, Brian F.; Adams, Jean V.; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

    2015-01-01

    We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

  9. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... open position and the swing span lights shall display as green to indicate the draw is in the full open... operated manually from the tender's house located at the bridge until all necessary repairs are...

  10. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... open position and the swing span lights shall display as green to indicate the draw is in the full open... operated manually from the tender's house located at the bridge until all necessary repairs are...

  11. 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.

  12. Groundwater-Lake Interaction in the Dead Sea Area

    NASA Astrophysics Data System (ADS)

    Kiro, Y.; Weinstein, Y.; Starinsky, A.; Yechieli, Y.

    2011-12-01

    The Dead Sea hypersaline water system is unique in terms of its unusual geochemical composition, rapid lake level changes and water composition of the brines discharging along its shoreline. The Dead Sea can be used as a natural lab for studying groundwater-seawater interaction and saline water hydrological circulation along the aquifer-sea boundary. It provides an opportunity to follow the geochemical processes along a flow path from the lake into the aquifer and back into the lake. The lake level has been dropping since the 1960's due to human interference in its water budget, reaching a rate of 1 m/yr in recent years. Saline water circulation in coastal aquifers may be a major process that governs trace element mass balances in coastal areas. This study uses radium isotopes in order to quantify the lake water circulation in the Dead Sea aquifer. There are four naturally-occurring radium isotopes, with half-lives ranging from 3.7 days to 1600 years which are chain products of uranium and thorium isotopes. Radium isotopes are usually enriched in saline groundwater and therefore are good candidates for estimating seawater or hypersaline lake water circulation in the aquifer. Compared to most natural water bodies, the Dead Sea is extremely enriched in radium and barium, where both 226Ra and 228Ra activities and Ba concentration (145, 1-2 dpm/L and 5 mg/L, respectively) are 2-3 orders of magnitude higher than in ocean water, whereas the salinity of the Dead Sea is only 10 times higher. Circulated Dead Sea water in the aquifer contains decreased concentrations of 226Ra (60 dpm/L), Ba (1.5 mg/L), Sr (300 relative to 340 mg/L in the Dead Sea) and Sulfate (250 relative to 392 mg/L). We suggest that the low 226Ra and Ba concentrations are due to precipitation of barite and celestine from the supersaturated Dead Sea water on entering the aquifer. 228Ra and the shorter-lived 224Ra and 223Ra, which have much lower activities in the Dead Sea (up to 1.8, 3 and 0.8 dpm

  13. Cassini Flybys Reveal Details About Titan Seas and Lakes

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2013-12-01

    The Cassini spacecraft's flybys of Saturn's moon Titan reveal new details about the sizes, depths, and locations of the seas and lakes, whose liquid is mostly methane, that dot the moon's northern hemisphere, according to findings presented by scientists at a 12 December news briefing at the AGU Fall Meeting in San Francisco, Calif.

  14. The Dead Sea, The Lake and Its Setting

    NASA Astrophysics Data System (ADS)

    Brink, Uri ten

    I cannot think of a subject more befitting the description of interdisciplinary research with societal relevance than the study of the Dead Sea, a terminal lake of the Jordan River in Israel and Jordan. The scientific study of the Dead Sea is intimately connected with politics, religion, archeology, economic development, tourism, and environmental change.The Dead Sea is a relatively closed geologic and limnologic system with drastic physical changes often occurring on human timescales and with a long human history to observe these changes. Research in this unique area covers diverse aspects such as active subsidence and deformation along strike-slip faults; vertical stratification and stability of the water column; physical properties of extremely saline and dense (1234 kg/m3) water; spontaneous precipitation of minerals in an oversaturated environment; origin of the unusual chemical composition of the brine; existence of life in extreme environments; use of lake level fluctuations as a paleoclimatic indicator; and effects on the environment of human intervention versus natural climatic variability. Although the Dead Sea covers a small area on a global scale, it is nevertheless one of the largest natural laboratories for these types of research on Earth. These reasons make the Dead Sea a fascinating topic for the curious mind.

  15. 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.

  16. Mercury accumulation in sea lamprey (Petromyzon marinus) from Lake Huron.

    PubMed

    Madenjian, Charles P; Johnson, Nicholas S; Siefkes, Michael J; Dettmers, John M; Blum, Joel D; Johnson, Marcus W

    2014-02-01

    We determined whole-fish total mercury (Hg) 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, bioenergetics modeling was used to explore the effects of sex-related differences in activity and resting (standard) metabolic rate (SMR) on mercury accumulation. The grand mean for Hg concentrations was 519 ng/g (standard error of the mean=46 ng/g). On average, males were 16% higher in Hg concentration than females. Bioenergetics modeling results indicated that 14% higher activity and SMR in males would account for this observed sex difference in Hg concentrations. We concluded that the higher Hg concentration in males was most likely due to higher rate of energy expenditure in males, stemming from greater activity and SMR. Our findings have implications for estimating the effects of sea lamprey populations on mercury cycling within ecosystems, as well as for the proposed opening of sea lamprey fisheries. Eventually, our results may prove useful in improving control of sea lamprey, a pest responsible for substantial damage to fisheries in lakes where it is not native.

  17. Mercury accumulation in sea lamprey (Petromyzon marinus) from Lake Huron

    USGS Publications Warehouse

    Madenjian, Charles P.; Johnson, Nicholas S.; Siefkes, Michael J.; Dettmers, John M.; Blum, Joel D.; Johnson, Marcus W.

    2014-01-01

    We determined whole-fish total mercury (Hg) 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, bioenergetics modeling was used to explore the effects of sex-related differences in activity and resting (standard) metabolic rate (SMR) on mercury accumulation. The grand mean for Hg concentrations was 519 ng/g (standard error of the mean = 46 ng/g). On average, males were 16% higher in Hg concentration than females. Bioenergetics modeling results indicated that 14% higher activity and SMR in males would account for this observed sex difference in Hg concentrations. We concluded that the higher Hg concentration in males was most likely due to higher rate of energy expenditure in males, stemming from greater activity and SMR. Our findings have implications for estimating the effects of sea lamprey populations on mercury cycling within ecosystems, as well as for the proposed opening of sea lamprey fisheries. Eventually, our results may prove useful in improving control of sea lamprey, a pest responsible for substantial damage to fisheries in lakes where it is not native.

  18. 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.

  19. Patterns of invasion and colonization of the sea lamprey (Petromyzon marinus) in North America as revealed by microsatellite genotypes.

    PubMed

    Bryan, M B; Zalinski, D; Filcek, K B; Libants, S; Li, W; Scribner, K T

    2005-10-01

    Invasions by exotic organisms have had devastating affects on aquatic ecosystems, both ecologically and economically. One striking example of a successful invader that has dramatically affected fish community structure in freshwater lakes of North America is the sea lamprey (Petromyzon marinus). We used eight microsatellite loci and multiple analytical techniques to examine competing hypotheses concerning the origins and colonization history of sea lamprey (n = 741). Analyses were based on replicated invasive populations from Lakes Erie, Huron, Michigan, and Superior, populations of unknown origins from Lakes Ontario, Champlain, and Cayuga, and populations of anadromous putative progenitor populations in North America and Europe. Populations in recently colonized lakes were each established by few colonists through a series of genetic bottlenecks which resulted in lower allelic diversity in more recently established populations. The spatial genetic structure of invasive populations differed from that of native populations on the Atlantic coast, reflecting founder events and connectivity of invaded habitats. Anadromous populations were found to be panmictic (theta(P) = 0.002; 95% CI = -0.003-0.006; P > 0.05). In contrast, there was significant genetic differentiation between populations in the lower and upper Great Lakes (theta(P) = 0.007; P < 0.05; 95% CI = 0.003-0.009). Populations in Lakes Ontario, Champlain, and Cayuga are native. Alternative models that describe different routes and timing of colonization of freshwater habitats were examined using coalescent-based analyses, and demonstrated that populations likely originated from natural migrations via the St Lawrence River.

  20. Heat pumps using heat from lakes and the sea

    NASA Astrophysics Data System (ADS)

    Davin, B. L.; Nordling, J.; Sandart, K.

    1981-01-01

    A study is presented on heat pump designs and processes in which lake or sea water both enters and leaves the heat exchanger used in the liquid state, so that only sensible (rather than liquid-solid phase transition, or latent) heat is extracted. Among the factors that must be considered in meeting these criteria are: (1) water temperature should not fall below 3 C, in order to avoid icing, and its average temperature should be as high as possible; (2) sufficient quantitites of water should be available at the lowest required temperature level, thereby eliminating the use of the smaller lakes as sources; (3) the corrosion risks of salinity must be weighed against its advantageous depression of the freezing point; and (4) biofouling must be prevented on all heat-transfer surfaces. Detailed performance and economic figure comparisons are given for 100 kW, 1 MW, and 10MW plants.

  1. Air-Sea Interactions over Lakes on Titan

    NASA Astrophysics Data System (ADS)

    Soto, Alejandro; Rafkin, Scot C. R.

    2016-10-01

    The exchange of methane between the atmosphere and surface liquid reservoirs dominates the short time-scale methanological cycle. In this study, previous two-dimensional simulations of the exchange of methane vapor, sensible heat and momentum between the atmosphere and lakes are updated with the inclusion of radiative forcing, three dimensions, and realistic coastlines. Titan's air-sea exchange in two dimensions indicated that the exchange process was self-limiting. Evaporation from lakes produced a shallow but extremely stable marine layer that suppressed turbulent exchange. Furthermore, the circulation associated with the higher buoyancy of methane-rich atmosphere over the lake was offset by the oppositely directed thermal sea breeze circulation, which muted the mean wind. Two major weaknesses of this previous work were the lack of radiative forcing and the imposition of two dimensionality, which limited the full range of dynamical solutions. Based on early theoretical studies, it was thought that magnitude of turbulent energy flux exchanges would be much larger than radiative fluxes, thereby justifying the neglect of radiation, but the two-dimensional simulations indicated that this was not a valid assumption. The dynamical limitations of two-dimensional simulations are well known. Vorticity stretching (i.e., circulation intensification through vertical motion) is not possible and it is also not possible to produce dynamically balanced gradient wind-type circulations. As well, the irregular shape of a realistic coastline cannot be expressed in two dimensions, and these realistic structures will generally induce complex convergence and divergence circulations in the atmosphere. The impact of radiative forcing and the addition of the third dimension on the air-sea exchange are presented.

  2. 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.

  3. Sea lamprey mark type, wounding rate, and parasite-host preference and abundance relationships for lake trout and other species in Lake Ontario

    USGS Publications Warehouse

    Lantry, Brian F.; Adams, Jean; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

    2015-01-01

    We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

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

    USGS Publications Warehouse

    King, Everett Louis

    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.Key words: sea lamprey, attack marks, lake trout, Great Lakes

  5. Arctic sea ice decline contributes to thinning lake ice trend in northern Alaska

    USGS Publications Warehouse

    Alexeev, Vladimir; Arp, Christopher D.; Jones, Benjamin M.; Cai, Lei

    2016-01-01

    Field measurements, satellite observations, and models document a thinning trend in seasonal Arctic lake ice growth, causing a shift from bedfast to floating ice conditions. September sea ice concentrations in the Arctic Ocean since 1991 correlate well (r = +0.69,p < 0.001) to this lake regime shift. To understand how and to what extent sea ice affects lakes, we conducted model experiments to simulate winters with years of high (1991/92) and low (2007/08) sea ice extent for which we also had field measurements and satellite imagery characterizing lake ice conditions. A lake ice growth model forced with Weather Research and Forecasting model output produced a 7% decrease in lake ice growth when 2007/08 sea ice was imposed on 1991/92 climatology and a 9% increase in lake ice growth for the opposing experiment. Here, we clearly link early winter 'ocean-effect' snowfall and warming to reduced lake ice growth. Future reductions in sea ice extent will alter hydrological, biogeochemical, and habitat functioning of Arctic lakes and cause sub-lake permafrost thaw.

  6. Arctic sea ice decline contributes to thinning lake ice trend in northern Alaska

    NASA Astrophysics Data System (ADS)

    Alexeev, Vladimir A.; Arp, Christopher D.; Jones, Benjamin M.; Cai, Lei

    2016-07-01

    Field measurements, satellite observations, and models document a thinning trend in seasonal Arctic lake ice growth, causing a shift from bedfast to floating ice conditions. September sea ice concentrations in the Arctic Ocean since 1991 correlate well (r = +0.69, p < 0.001) to this lake regime shift. To understand how and to what extent sea ice affects lakes, we conducted model experiments to simulate winters with years of high (1991/92) and low (2007/08) sea ice extent for which we also had field measurements and satellite imagery characterizing lake ice conditions. A lake ice growth model forced with Weather Research and Forecasting model output produced a 7% decrease in lake ice growth when 2007/08 sea ice was imposed on 1991/92 climatology and a 9% increase in lake ice growth for the opposing experiment. Here, we clearly link early winter ‘ocean-effect’ snowfall and warming to reduced lake ice growth. Future reductions in sea ice extent will alter hydrological, biogeochemical, and habitat functioning of Arctic lakes and cause sub-lake permafrost thaw.

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

    NASA Astrophysics Data System (ADS)

    Hazan, N.; Stein, M.; Agnon, A.; Marco, S.; Nadel, D.; Negendank, J. F. W.; Schwab, M. J.; Neev, D.

    2005-01-01

    The freshwater Lake Kinneret (Sea of Galilee) and the hypersaline Dead Sea are remnant lakes, evolved from ancient water bodies that filled the tectonic depressions along the Dead Sea Transform (DST) during the Neogene-Quartenary periods. We reconstructed the limnological history (level and composition) of Lake Kinneret during the past ˜40,000 years and compared it with the history of the contemporaneous Lake Lisan from the aspect of the regional and global climate history. The lake level reconstruction was achieved through a chronological and sedimentological investigation of exposed sedimentary sections in the Kinnarot basin trenches and cores drilled at the Ohalo II archeological site. Shoreline chronology was established by radiocarbon dating of organic remains and of Melanopsis shells. The major changes in Lake Kinneret level were synchronous with those of the southern Lake Lisan. Both lakes dropped significantly ˜42,000, ˜30,000, 23,800, and 13,000 yr ago and rose ˜39,000, 26,000, 5000, and 1600 yr ago. Between 26,000 and 24,000 yr ago, the lakes merged into a unified water body and lake level achieved its maximum stand of ˜170 m below mean sea level (m bsl). Nevertheless, the fresh and saline water properties of Lake Kinneret and Lake Lisan, respectively, have been preserved throughout the 40,000 years studied. Calcium carbonate was always deposited as calcite in Lake Kinneret and as aragonite in Lake Lisan-Dead Sea, indicating that the Dead Sea brine (which supports aragonite production) never reached or affected Lake Kinneret, even during the period of lake high stand and convergence. The synchronous level fluctuation of lakes Kinneret, Lisan, and the Holocene Dead Sea is consistent with the dominance of the Atlantic-Mediterranean rain system on the catchment of the basin and the regional hydrology. The major drops in Lake Kinneret-Lisan levels coincide with the timing of cold spells in the North Atlantic that caused a shut down of rains in the East

  8. Freshwater mass balance and exchange of water masses with the open sea: the Mljet Lakes (Croatia, Adriatic Sea)

    NASA Astrophysics Data System (ADS)

    Martincic, Urska; Bezak, Nejc; Zagar, Dusan; Makovec, Tihomir; Lucic, Davor; Onofri, Vladimir; Malacic, Vlado

    2016-04-01

    Two karstic seawater lakes (Veliko - Big and Malo - Small Lake) located in the National Park Mljet on the Mljet Island in Croatia were investigated in this study. The Small and the Big Lake cover 0.25 and 1.45 km2, respectively. The two lakes are connected to each other and to the sea by narrow channels. The connecting channel between the Big Lake and the sea is 12 m wide and 3 m deep. The connection to the Small Lake leads through another artificial channel (2.7 m wide and 0.8 m deep). The average salinity of the Big and the Small lake is 37.75 and 36.9, respectively, and the average salinity of the open sea is 38.5. While previous studies have been conducted due to the lakes' unique ecosystem and the karstic characteristics of the area, the main aim of this study was to determine the freshwater mass balance and exchange of water masses with the nearby sea. Several measurement campaigns were performed between 2008 and 2015 when meteorological parameters as well as salinity, water temperature and water velocities in both lakes and the channels were observed. A perpetual year was determined using available meteorological data. The contribution of the surface runoff to both lakes was modelled using the hydrological rainfall-runoff HEC-HMS model. Curve number parameter was estimated using the CLC Corine Land cover and geomorphological maps. Evaporation from the lake was calculated using the Verburg, Kondo and Coare equations. We found that the annual evaporation approximately equals the annual rainfall to the lake surface (cca. 550-600 mm). From the hydrological model and the difference between precipitation and evaporation from the lake surface we calculated the annual net excess of freshwater between 0.5 106 and 0.7 106 m3. The average salinity in both lakes is lower than the salinity in the sea; therefore, we hypothesize that the excess water should be discharged either through the channel between the Big Lake and the open sea or through underwater karstic sink

  9. Changes in the lake trout population of southern Lake Superior in relation to the fishery, the sea lamprey, and stocking, 1950-70

    USGS Publications Warehouse

    Pycha, Richard L.; King, George R.

    1975-01-01

    Reduction of sea lamprey abundance resulted in an immediate increase in survival and abundance of lake trout, especially of the larger sizes. As abundance of lake trout progressively increased in 1962-70, survival of the smaller legal-size lake trout increased, probably due to reduction of the predator-prey ratio and an increase in availability of larger lake trout preferred by sea lampreys. Abundance of spawning-size lake trout was limited by high natural mortality in 1965-70. Circumstantial evidence suggested that sea lamprey predation contributed a major part of the high natural mortality.

  10. Evidence that lake trout served as a buffer against sea lamprey predation on burbot in Lake Erie

    USGS Publications Warehouse

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

    2007-01-01

    The population of burbot Lota lota in Lake Erie recovered during 1986–2003, mainly because of the control of sea lamprey Petromyzon marinus, which began in 1986. Burbot populations continued to grow during 1996–1998, when sea lamprey control was substantially reduced. We calculated mortality parameters for burbot in Lake Erie by estimating age at capture for 2,793 burbot caught in annual gill-net surveys of eastern Lake Erie from 1994 to 2003. Based on catch-curve analysis, annual mortality in Lake Erie during 1994–2003 was estimated as 33%. Annual mortality of the 1992 year-class of burbot was estimated as 30%. The mortality of burbot during the years of reduced sea lamprey control was not different from that during the 3 years preceding reduced control and was significantly lower than that during the entire portion of the time series in which full sea lamprey control was conducted. These results suggest that the reduction in sea lamprey control did not lead to increased burbot mortality. The catch per gill-net lift of large burbot (total length > 600 mm), the size preferred by sea lampreys, was lower than that of adult lake trout Salvelinus namaycush (age 5 and older; total length > 700 mm) before lampricide application was reduced. Although adult lake trout populations declined, the abundance of large burbot did not change during the period of reduced lampricide application. These results support a hypothesis that a healthy population of adult lake trout can serve as a buffer species, acting to reduce predation of burbot by sea lampreys when sea lamprey populations increase. Burbot attained sexual maturity at a relatively early age (3 or 4 years) and a total length (approximately 500 mm) that was smaller than the preferred prey size for sea lampreys. These characteristics and the buffering effect of the lake trout population enabled growth of the burbot population during the brief period when lamprey control was reduced.

  11. The Ancylus Lake stage of the Baltic Sea in Fehmarn Belt: Indications of a new threshold?

    NASA Astrophysics Data System (ADS)

    Feldens, Peter; Schwarzer, Klaus

    2012-03-01

    The Baltic Ice Lake, Yoldia Sea, Ancylus Lake and Littorina Sea stages of regression and transgression controlled the history of the Baltic Sea since the last glacial period. Many details regarding their development remain unknown, including the question whether the regression of the Ancylus Lake (between 10,700 and 10,200 cal yr BP) took place west of the Darss Sill, or elsewhere. This study addresses whether a drowned river system in Fehmarn Belt (SW Baltic Sea) can be related to the drainage of the Ancylus Lake. The river channel is cut into glacial till in the western part of Fehmarn Belt. Here, the channel reaches an incision depth of up to 12 m at a base level of 40 m b.s.l. (below sea level). Near Mecklenburg Bay, the buried channel is incised down to 60 m b.s.l. and widens rapidly from several hundred meters to more than 1 km, fading towards east. It was mainly shaped as part of a glacial meltwater system at a maximum water level of 30 m b.s.l., and is therefore not related to the Ancylus Lake drainage. During the lowstand of the Baltic Ice Lake, local shallow water bodies covered the study area. A previously reported westward directed drainage of a lake in the eastern Fehmarn Belt could be restricted to a time interval between the highstand of the Ancylus Lake and prior to the Littorina Transgression. Timing, water level and potential water discharge of this event suggest a connection to a partial drainage of the Ancylus Lake. It is concluded that the threshold separating the Ancylus Lake from the North Sea needs to be located west of Fehmarn Belt.

  12. 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.

  13. Simulating the water balance of the Aral Sea with a coupled regional climate-lake model

    USGS Publications Warehouse

    Small, E.E.; Sloan, L.C.; Hostetler, S.; Giorgi, F.

    1999-01-01

    Before coupled atmosphere-lake models can be used to study the response of large lake systems to climatic forcings, we must first evaluate how well they simulate the water balance and associated lake atmosphere interactions under present-day conditions. We evaluate the hydrology simulated by a lake model coupled to NCAR's regional climate model (RegCM2) in a study of the Aral Sea. The meteorological variables that are input to the lake model are simulated well by RegCM2. Simulated surface air temperatures closely match observed values, except during spring and fall when the simulated temperatures are too cold. The magnitude of precipitation is too high in the region surrounding the Aral Sea during summer and fall. On a yearly basis, RegCM2 produces a reasonable amount of runoff throughout the drainage basin. The lake model coupled to RegCM2 accurately simulates Aral Sea surface temperatures (SSTs). The lake model also simulates observed mid-winter ice fraction well, although the onset of ice growth occurs too late in the year and the ice melts too rapidly in the spring. The simulated annual evaporation from the Aral Sea is consistent with observed estimates; however, the simulated evaporation is greater than observed during summer and less than observed during winter. In a "stand-alone" lake model simulation, the simulated Aral Sea hydrology does not match observations as closely as in the coupled model experiment. These results suggest that a stand-alone lake model would not accurately simulate the hydrologic response of the Aral Sea to various forcings. Copyright 1999 by the American Geophysical Union.

  14. Life history of the sea lamprey of Cayugaf Lake, New York

    USGS Publications Warehouse

    Wigley, Roland L.

    1959-01-01

    A life history study of the sea lamprey, Petromyson marinus Linnaeus, in Cayuga Lake, N.Y., was conducted during 1950, 1951, and 1952. One of the major objectives was to obtain biological data concerning this endemic stock of sea lampreys for comparison with the newly established stocks in the Great Lakes. Sexually mature sea lampreys captured on their spawning migration in Cayuga Inlet were the basis of much of this study. Such items as meristic counts, body proportions, body color, sex ratios, lengths and weights, fecundity, rate of upstream travel, effect of dams in retarding upstream movement, nesting habits, parasites, predators, estimates of abundance, and morphological changes were based on mature upstream migrants. Sea lampreys were procured by weir and trap operations and captured by hand. Tagging and marking' programs each spring made it possible to determine movements and morphological changes of individual lampreys, in addition to estimating the number of upstream migrants. Growth of parasitic-phase sea lampreys was estimated from measurements of specimens captured in Cayuga Inlet and Cayuga Lake proper. The incubation period of lamprey eggs and the habits of ammocoetes and transforming lampreys were ascertained from specimens kept in hatchery troughs and raceways. Length-frequency and weight-frequency distributions, together with the length-weight regression, of ammocoetes from Cayuga Inlet were utilized for estimating the duration of their larval life. Lake trout, Salvelinus n. namayc"Ush (Walbaum), from Cayuga Lake and Seneca Lake were the subject of an inquiry into the effects of sea lamprey attacks. Incidence of sea lamprey attacks on the white sucker, Catosto7llus c. commerson/: (LacepMe), was investigated. Three methods are suggested for reducing the number of sea lampreys in Cayuga Lake.

  15. Speciation of ¹²⁹I in sea, lake and rain waters.

    PubMed

    Lehto, Jukka; Räty, Tero; Hou, Xiaolin; Paatero, Jussi; Aldahan, Ala; Possnert, Göran; Flinkman, Juha; Kankaanpää, Harri

    2012-03-01

    Concentrations of the very long-lived fission product (129)I and stable iodine ((127)I) in the Baltic Sea and lake and rain waters from Finland, were measured as well as their occurrence as iodide (I(-)) and iodate (IO(3)(-)). The highest concentrations of both (127)I and (129)I occurred in sea water, on average 11.1 ± 4.3 μg/l and 3.9 ± 4.1 × 10(-9) at/l. In rain and lake waters the concentration of (129)I was more or less identical and almost one order of magnitude lower than in sea water. Based on these observations, and data from the literature, it is assumed that the source of (129)I in lakes is precipitation and the major source in the Baltic Sea is the inflow of sea water from the North Sea through the Danish Straits. The concentration of (129)I in the Baltic Sea has increased by a factor of six during ten years from 1999. In all studied water types the main chemical form of both iodine isotopes was iodide; in sea and lake waters by 92-96% and in rain water by 75-88%. Compared to (127)I the fraction of iodide was slightly higher in case of (129)I in all waters.

  16. 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.

  17. Shrinking sea ice, increasing snowfall and thinning lake ice: a complex Arctic linkage explained

    NASA Astrophysics Data System (ADS)

    Brock, Ben W.

    2016-09-01

    The dramatic shrinkage of Arctic sea ice is one of the starkest symptoms of global warming, with potentially severe and far-reaching impacts on arctic marine and terrestrial ecology (Post et al 2013 Science 341 519-24) and northern hemisphere climate (Screen et al 2015 Environ. Res. Lett. 10 084006). In their recent article, Alexeev et al (2016 Environ. Res. Lett. 11 074022) highlight another, and unexpected, consequence of Arctic sea ice retreat: the thinning of lake ice in northern Alaska. This is attributed to early winter ‘ocean effect’ snowfall which insulates lake surfaces and inhibits the formation of deep lake ice. Lake ice thinning has important consequences for Arctic lake hydrology, biology and permafrost degradation.

  18. Salinization forced anoxia in the Sea of Aral, the Dead Sea and the Urmia Lake: a temporal feature of the salt lakes development under the Global Change?

    NASA Astrophysics Data System (ADS)

    Yakushev, Evgeniy; Ghaffari, Peygham; Zavialov, Petr; Kurbaniyazov, Abilgazi

    2016-04-01

    The Sea of Aral is undergone a process of its volume decrease and salinization started about 30 years ago. In the remained now lake in the former deepest part of the Sea the salinity increased from about 8 PSU in 1990 to 120 PSU in the surface layer, and 240 PSU in the bottom layer in 2015. On top of an increase of salinity, there was formed a sulfidic zone in the bottom layer, that was separated from the upper layer by an extremely strong halocline (more than 50 PSU in 100 cm). The reason of this halocline might be an influx of the heavy high salinity water formed in summer in the shallower part of the Aral Sea to the bottom layer of the deeper part of the Sea through a strait between them. The similar processes could take place in the Urmia Lake, where salinity increased from 120 PSU in 2000 to about 350-400 PSU in 2015. This lake also consists from a shallow and deep parts connected by a channel in the dam, and where there was also reported anoxia. And finally, the Dead Sea demonstrates a further development happened after the shallower Southern part of the Sea was totally evaporated. After 1993 the vertical mixing started to occur down to the bottom layer, and the lake regime changed from meromictic to monomictic, that resulted in aeration of the bottom layer. In this work we compare interannual changes of the main salinity components in the 3 water bodies and analyze results of the vertical chemical structure of the Sea of Aral studied in 2015.

  19. Declining Sea Ice Extent Links Early Winter Climate to Changing Arctic Lakes

    NASA Astrophysics Data System (ADS)

    Alexeev, V. A.; Arp, C. D.; Jones, B. M.; Cai, L.

    2015-12-01

    Lakes on the Alaskan North Slope regulate surface energy balance and interactions with permafrost as well as providing important habitat. Winter lake ice regimes (floating-ice or bedfast-ice conditions) determine whether lakes develop and maintain taliks and can support overwintering fish habitat. Lake ice thickness is a key variable determining whether a lake has a bedfast or floating-ice regime. Recent observations suggest a trend towards more lakes with floating-ice conditions due to thinner ice growth, but the broader scale associated climate conditions driving these regime shift are less certain. This study finds that the changing arctic summer/fall sea ice conditions might be affecting lake ice thickness on the North Slope. Late ocean freeze-up near the Alaskan coast leads to warmer weather and more snowfall in the early winter. Warmer early winters and thicker snowpack result in thinner lake ice the following winter thus potentially developing more ice-floating lakes before the start of the summer. Experiments with a regional atmospheric model WRF for two years with very different sea ice conditions indicate that the extent of open water next to the North Slope is a crucial factor for developing thicker snowpack, also warmer air temperature in early winter.

  20. Estimation of Snow Thickness on Sea Ice and Lake Ice Using Airborne SnowSAR Data

    NASA Astrophysics Data System (ADS)

    Veijola, Katriina; Makynen, Marko; Lemmetyinen, Juha; Praks, Jaan

    2016-08-01

    Currently, snow thickness on sea ice is operationally estimated using microwave radiometer data. However, the estimates are hampered by the inherent coarse spatial resolution of passive microwave sensors. Successful application of SAR imagery for snow thickness estimation has the potential of providing estimates of snow thickness with much finer spatial resolution.In this study, we concentrate on assessing the capability of X- and Ku-band SAR backscattering to estimate snow thickness on sea and lake ice. Co- and cross -polarized X- and Ku-band SAR backscattering data, acquired with the ESA airborne SnowSAR sensor, are applied. The SAR data acquisition and co-incident in-situ measurements were conducted in Finland in the winter of 2012 over sea ice and lake ice test sites.Our analysis shows which frequency and polarization combinations have best sensitivity to snow thickness on sea and lake ice and in deep discussion provides plausible ways to improve the results.

  1. Evidence that sea lampreys (Petromyzon marinus) complete their life cycle within a tributary of the Laurentian Great Lakes by parasitizing fishes in inland lakes

    USGS Publications Warehouse

    Johnson, Nicholas; Twohey, Michael B.; Miehls, Scott M.; Cwalinski, Tim A; Godby, Neal A; Lochet, Aude; Slade, Jeffrey W.; Jubar, Aaron K.; Siefkes, Michael J.

    2016-01-01

    The sea lamprey (Petromyzon marinus) invaded the upper Laurentian Great Lakes and feeds on valued fish. The Cheboygan River, Michigan, USA, is a large sea lamprey producing tributary to Lake Huron and despite having a renovated dam 2 km from the river mouth that presumably blocks sea lamprey spawning migrations, the watershed upstream of the dam remains infested with larval sea lamprey. A navigational lock near the dam has been hypothesized as the means of escapement of adult sea lampreys from Lake Huron and source of the upper river population (H1). However, an alternative hypothesis (H2) is that some sea lampreys complete their life cycle upstream of the dam, without entering Lake Huron. To evaluate the alternative hypothesis, we gathered angler reports of lamprey wounds on game fishes upstream of the dam, and captured adult sea lampreys downstream and upstream of the dam to contrast abundance, run timing, size, and statolith microchemistry. Results indicate that a small population of adult sea lampreys (n < 200) completed their life cycle upstream of the dam during 2013 and 2014. This is the most comprehensive evidence that sea lampreys complete their life history within a tributary of the upper Great Lakes, and indicates that similar landlocked populations could occur in other watersheds. Because the adult sea lamprey population upstream of the dam is small, complete elimination of the already low adult escapement from Lake Huron might allow multiple control tactics such as lampricides, trapping, and sterile male release to eradicate the population.

  2. 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 1983−1986. 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.

  3. Recommendations for assessing sea lamprey damages: toward optimizing the control program in the Great Lakes

    USGS Publications Warehouse

    Stewart, Thomas J.; Bence, James R.; Bergstedt, Roger A.; Ebener, Mark P.; Lupi, Frank; Rutter, Michael A.

    2003-01-01

    The Great Lakes sea lamprey (Petromyzon marinus) control program currently allocates stream treatments to optimize the number of juvenile sea lampreys killed for a given level of control. Although the economic benefits derived from control appear to outweigh the dollars spent on control efforts, optimizing the number of sea lampreys killed will not necessarily optimize the economic benefits provided by the fish communities. These benefits include both non-consumptive and fishery values. We emphasize that the biological damages caused by each juvenile sea lamprey will vary, as will the economic value associated with each host that is killed. We consider issues related to assessing damages due to sea lampreys, taking into account effects on the fish community and fisheries, so as to improve the sea lamprey control program. We recommend a consolidation of information regarding the valuation of benefits, better understanding of variation in host-parasite interactions among the Great Lakes, and integration of the control program with other fisheries management objectives and activities. Adoption of these recommendations should promote lake trout rehabilitation in the Great Lakes, healthy fish communities and prudent use of limited fishery management resources.

  4. Paleolimnological and geochronological studies of salt lakes of Crimea, the Black Sea area

    NASA Astrophysics Data System (ADS)

    Subetto, D. A.; Sapelko, T. V.; Kuznetsov, D. D.; Ludikova, A. V.; Gerasimenko, N.; Stolba, V.; Bakhmutov, V.

    2009-04-01

    1. Crimea is one of the few places in the northern Black Sea region with mineral lakes with sediments that can give information about paleoclimate and environmental changes over a long time period. All of these lakes are shallow (c. 1-1.5 m), saline of marine origin (former marine bays and lagoons), the emergence of which took place in ‘historical' time (c. 5000 yrs ago). 2. The thickness of sediments is reaching up to 20-25 m. The recovery of long sediment sequences permits comparative study of the complex interactions among humans, climate and environment in the Crimea. Moreover, it provides an opportunity to establish a direct chronological link between major ethno-historical and economic processes on the one hand and climatic changes such as wet-dry circles that affected the whole area on the other. 3. Two lake sediment sequences have been recovered from the Crimean Peninsula ((Lake Saki (45° 06',8N; 33° 33',2E, water depth ca 0.8 m, recovered sediments 4.2 m) and Lake Dzharylgach(45° 34',7N; 32° 51',7E, water depth ca 0.8 m, recovered sediments 4.15 m)) during the field campaign 2005, as part of the Joint Danish-Russian-Ukraine project called "Northern Black Sea in the 1st millennium BC: human history and climate changes". In 2006, a detailed examination of the cores was carried out by the team members from the Institute of Limnology, RAS, St Petersburg, the National Taras Shevchenko University of Kyiv, and the Institute of Physics of the Earth, NASU, Kiev. The detailed examination of the cores, which includes varve counting, lithostratigraphy, geochemistry, pollen, diatom and ostracods analyses is presently being carried out. The AMS 14C dating is being processed by the Radiocarbon Laboratory, Institute of Physics and Astronomy. 4. In the both studied lakes, marine sediments overlain by mineralized lake sediments were recovered. The oldest dates from marine sediment from both studied sequences are 5500-5370 cal BP (L.Saki) and 7200-7050 cal BP (L

  5. Growth and survival of sea lampreys from metamorphosis to spawning in Lake Huron

    USGS Publications Warehouse

    Swink, William D.; Johnson, Nicholas S.

    2014-01-01

    Larval Sea Lampreys Petromyzon marinus live burrowed in stream bottoms and then metamorphose into their parasitic stage. Among larvae that metamorphose in a given year (i.e., parasitic cohort), autumn out-migrants (October–December) to the Laurentian Great Lakes can feed on fish for up to 6 months longer than spring outmigrants (March–May), which overwinter in streams without feeding. We evaluated whether the season of outmigration affected growth or survival of newlymetamorphosed Sea Lampreys in LakeHuron. Newlymetamorphosed individuals (n=2,718) from three parasitic cohorts were netted during their out-migration from BlackMallard Creek, Michigan, to LakeHuron during autumn 1997 through spring 2000; each out-migrant was injected with a sequentially numbered coded wire tag and was released back into the creek. After up to 18 months of feeding in the Great Lakes, 224 (8.2%) Sea Lampreys were recaptured (in 1999–2001) as upstream-migrating adults in tributaries to Lakes Huron and Michigan. Recovery rates of autumn and spring out-migrants as adults were 9.4% and 7.8%, respectively, and these rates did not significantly differ. Overwinter feeding (i.e., as parasites) by autumn out-migrants did not produce adult mean sizes greater than those of spring out-migrants. Because we detected no growth or survival differences between autumn and spring out-migrants, the capture of newly metamorphosed Sea Lampreys at any point during their out-migration should provide equal reductions in damage to Great Lakes fisheries. The absence of a difference in growth or survival between autumn and spring out-migrants is an aspect of Sea Lamprey life history that yields resiliency to this invasive parasite and complicates efforts for its control in the Great Lakes.

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

    SciTech Connect

    Swink, W.D. )

    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.

  7. 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.

  8. Sea lamprey (Petromyzon marinus) parasite-host interactions in the Great Lakes

    USGS Publications Warehouse

    Bence, James R.; Bergstedt, Roger A.; Christie, Gavin C.; Cochran, Phillip A.; Ebener, Mark P.; Koonce, Joseph F.; Rutter, Michael A.; Swink, William D.

    2003-01-01

    Prediction of how host mortality responds to efforts to control sea lampreys (Petromyzon marinus) is central to the integrated management strategy for sea lamprey (IMSL) in the Great Lakes. A parasite-host submodel is used as part of this strategy, and this includes a type-2 multi-species functional response, a developmental response, but no numerical response. General patterns of host species and size selection are consistent with the model assumptions, but some observations appear to diverge. For example, some patterns in sea lamprey marking on hosts suggest increases in selectivity for less preferred hosts and lower host survival when preferred hosts are scarce. Nevertheless, many of the IMSL assumptions may be adequate under conditions targeted by fish community objectives. Of great concern is the possibility that the survival of young parasites (parasitic-phase sea lampreys) varies substantially among lakes or over time. Joint analysis of abundance estimates for parasites being produced in streams and returning spawners could address this. Data on sea lamprey marks is a critical source of information on sea lamprey activity and potential effects. Theory connecting observed marks to sea lamprey feeding activity and host mortality is reviewed. Uncertainties regarding healing and attachment times, the probability of hosts surviving attacks, and problems in consistent classification of marks have led to widely divergent estimates of damages caused by sea lamprey. Laboratory and field studies are recommended to provide a firmer linkage between host blood loss, host mortality, and observed marks on surviving hosts, so as to improve estimates of damage.

  9. 77 FR 67319 - Drawbridge Operation Regulation; Lake Champlain, Swanton, VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    .... United States Code A. Public Participation and Request for Comments We encourage you to participate in... train. Presently, rail traffic crosses the bridge seven days a week. There are normally two train... would remain in the open position at all times, except for the passage of rail traffic. Once...

  10. The lakes and seas of Titan: outstanding questions and future exploration

    NASA Astrophysics Data System (ADS)

    Stofan, Ellen R.; Lunine, Jonathan; Lorenz, Ralph

    2010-04-01

    More than 400 lakes have been identified near Titan's north pole, with sizes that range from a few km2 to seas in excess of 100,000 km2. The lakes and seas fill through rainfall and/or intersection with the subsurface liquid methane table, and provide the first evidence for an active condensable-liquid cycle on another planetary body. Many aspects of Titan's seas are unknown, including their composition, depth, and shoreline characteristics, but are key to understanding Titan's hydrological cycle. In addition to ethane, methane and nitrogen, Titan's seas will likely contain dissolved amounts of many other compounds. It is possible that further chemistry may take place, yielding prebiotic molecules impossible to form in the gas phase. It has even been suggested that autocatalytic chemical cycles might yield far-from-equilibrium abundance patterns or mimic the functionality of biological systems. The Titan Mare Explorer (TiME) is a Discovery-class mission to a Titan sea that provides in situ measurements to constrain Titan's active methane cycle as well as its intriguing prebiotic organic chemistry. The target for TiME is Ligeia Mare, at 78°N, 250°W, one of the largest seas identified on Titan. TiME would test the Advanced Stirling Radioisotope Generators (ASRGs), and would pioneer low-cost, outer solar system missions. Science objectives for TiME include measuring the chemistry of the sea to determine their role as a source and sink of methane and its chemical products, determining the depth of the sea to help constrain organic inventory, ascertaining marine processes including the nature of the sea surface and sea circulation, and determining sea surface meteorology. TiME science is fundamental, and will provide the first in situ exploration of an extraterrestrial sea, the first in situ measurements of an active liquid cycle beyond Earth, and aid in understanding the limits of life in our solar system.

  11. 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…

  12. Control of the sea lamprey (Petromyzon marinus) in Lake Superior, 1953-70

    USGS Publications Warehouse

    Smith, Bernard R.; Tibbles, J. James; Johnson, B.G.H.

    1974-01-01

    Although sea lamprey control and heavy plantings of hatchery-reared stock had restored lake trout abundance to prelamprey levels in many areas by 1970, the trout had not yet become self-sustaining. Additional effort will be required to further reduce the effects of lamprey predation.

  13. Estimating lake-wide abundance of spawning-phase sea lampreys (Petromyzon marinus) in the Great Lakes: extrapolating from sampled streams using regression models

    USGS Publications Warehouse

    Mullett, Katherine M.; Heinrich, John W.; Adams, Jean V.; Young, Robert J.; Henson, Mary P.; McDonald, Rodney B.; Fodale, Michael F.

    2003-01-01

    Lake-wide abundance of spawning-phase sea lampreys (Petromyzon marinus) can be used as one means to evaluate sea lamprey control efforts in the Great Lakes. Lake-wide abundance in each Great Lake was the sum of estimates for all streams thought to contribute substantial numbers of sea lampreys. A subset of these streams was sampled with traps and mark-recapture studies were conducted. When sea lampreys were captured in traps, but no mark-recapture study was conducted, abundance was estimated from a relation between trap catch and mark-recapture estimates observed in other years. In non-sampled streams, a regression model that used stream drainage area, geographic region, larval sea lamprey, production potential, the number of years since the last lampricide treatment, and spawning year was used to predict abundance of spawning-phase sea lampreys. The combination of estimates from sampled and non-sampled streams provided a 20-year time series of spawning-phase sea lamprey abundance estimates in the Great Lakes.

  14. Importance of coastal change variables in determining vulnerability to sea- and lake-level change

    USGS Publications Warehouse

    Pendleton, E.A.; Thieler, E.R.; Williams, S.J.

    2010-01-01

    In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height, coastal slope, historical shoreline change rate, geomorphology, and historical rate of relative sea- or lake-level change. This approach seeks to combine a coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, and it provides a measure of the system's potential vulnerability to the effects of sea- or lake-level change. Assessments for 22 park units are combined to evaluate relationships among the variables used to derive the index. Results indicate that Atlantic and Gulf of Mexico parks have the highest vulnerability rankings relative to other park regions. A principal component analysis reveals that 99% of the index variability can be explained by four variables: geomorphology, regional coastal slope, water-level change rate, and mean significant wave height. Tidal range, ice cover, and historical shoreline change are not as important when the index is evaluated at large spatial scales (thousands of kilometers

  15. Production of sea lamprey larvae from nests in two Lake Superior streams

    USGS Publications Warehouse

    Manion, Patrick J.

    1968-01-01

    The life history of the landlocked sea lamprey, Petromyzon marinus, has been described by several authors, the two most recent of which are Applegate and Wigley. The only information on the production of larvae from nests of the sea lamprey was reported by Applegate, who counted the larvae from three nests in the Ocqueoc River, a tributary of Lake Huron. The present report presents data on the hatching success of sea lamprey larvae from 19 nests in two small tributaries of southern Lake Superior and indicates greater production per nest than that recorded by Applegate. Studies were conducted by personnel of the U.S. Bureau of Commercial Fisheries on the Little Garlic River, Marquette County, Michigan, and on the Traverse River, Keweenaw County, Michigan.

  16. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of...

  17. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of...

  18. 78 FR 76140 - Extension of Public Comment Period for the Champlain Hudson Power Express Transmission Line...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-16

    ... Extension of Public Comment Period for the Champlain Hudson Power Express Transmission Line Project Draft... Hudson Power Express Transmission Line Project Draft Environmental Impact Statement (DOE/EIS-0447). The... permit to the Applicant, Champlain Hudson Power Express, Inc. (CHPEI), to construct, operate,...

  19. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Quality Control Region. 81.48 Section 81.48 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of...

  20. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Quality Control Region. 81.48 Section 81.48 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of...

  1. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Quality Control Region. 81.48 Section 81.48 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.48 Champlain Valley Interstate Air Quality Control Region. The Champlain Valley Interstate Air Quality Control Region (Vermont-New York) has been revised to consist of...

  2. Estimating parasitic sea lamprey abundance in Lake Huron from heterogenous data sources

    USGS Publications Warehouse

    Young, Robert J.; Jones, Michael L.; Bence, James R.; McDonald, Rodney B.; Mullett, Katherine M.; Bergstedt, Roger A.

    2003-01-01

    The Great Lakes Fishery Commission uses time series of transformer, parasitic, and spawning population estimates to evaluate the effectiveness of its sea lamprey (Petromyzon marinus) control program. This study used an inverse variance weighting method to integrate Lake Huron sea lamprey population estimates derived from two estimation procedures: 1) prediction of the lake-wide spawning population from a regression model based on stream size and, 2) whole-lake mark and recapture estimates. In addition, we used a re-sampling procedure to evaluate the effect of trading off sampling effort between the regression and mark-recapture models. Population estimates derived from the regression model ranged from 132,000 to 377,000 while mark-recapture estimates of marked recently metamorphosed juveniles and parasitic sea lampreys ranged from 536,000 to 634,000 and 484,000 to 1,608,000, respectively. The precision of the estimates varied greatly among estimation procedures and years. The integrated estimate of the mark-recapture and spawner regression procedures ranged from 252,000 to 702,000 transformers. The re-sampling procedure indicated that the regression model is more sensitive to reduction in sampling effort than the mark-recapture model. Reliance on either the regression or mark-recapture model alone could produce misleading estimates of abundance of sea lampreys and the effect of the control program on sea lamprey abundance. These analyses indicate that the precision of the lakewide population estimate can be maximized by re-allocating sampling effort from marking sea lampreys to trapping additional streams.

  3. CLEAN SEA project: the test in Lake Vättern (Sweden)

    NASA Astrophysics Data System (ADS)

    Locritani, Marina; Carmisciano, Cosmo

    2016-04-01

    The CLEAN SEA (Continuous Long-term Environmental and Asset iNtegrity monitoring at SEA) project has been realized by eni e&p and its subsidiary Eni Norge in cooperation with Tecnomare in 2012. The aim of the project is to use a commercially available AUV properly upgraded, installed and operated by SAAB AUV, for the execution of environmental monitoring in offshore zone. We participated to the project performing the environmental characterization of site (Lake Vättern, Sweden) selected for the field test of Clean Sea project, and to providing support to processing the collected data by the payload installed. In detail, in the first phase of the project, we characterized the site of interest analyzing the clime, the morphology, and the principal chemical and physical water and environmental parameters on the basis of historical data (meteorology, hydrology, hydrodynamic, wind, ice cover and natural resources of the lake). In the second phase of the project, we processed the oceanographic and environmental data acquired in Lake Vättern during the AUV tests. The tests have been performed in two different areas in the East and West side of the lake. In detail Temperature, Salinity, Methane, Turbidity, Chlorophyll, Colored Dissolved Organic Matter, Polycyclic Aromatic Hydrocarbons, Oxygen, pH, Oxidation Reduction Potential, Refined Oil and Crude Oil have been acquired in 21 different tests with 4 different mission types, and successively processed and evaluated. The analysis highlights the spatial and temporal variability for each parameter, and allows the comparison with the available historical data.

  4. Mark-recapture population estimates of parasitic sea lampreys (Petromyzon marinus) in Lake Huron

    USGS Publications Warehouse

    Bergstedt, Roger A.; McDonald, Rodney B.; Mullett, Katherine M.; Wright, Gregory M.; Swink, William D.; Burnham, Kenneth P.

    2003-01-01

    Metamorphosed sea lampreys (Petromyzon marinus) were collected and marked at two points in their life cycle. Recently metamorphosed juveniles were collected from streams, marked with coded wire tags, and returned to migrate to the Great Lakes. Juveniles already in the lakes and feeding on teleost hosts were obtained from incidental catches by sport or commercial fisheries. Sea lampreys in the Great Lakes spend only 1 feeding year as parasites, and marked animals were recaptured during the spawning runs. For one marked group in each of four parasitic cohorts (feeding years 1991 to 1994) and two marked groups in each of three cohorts (feeding years 1998 to 2000) we recovered from 1.1 to 10.2 percent of marked animals. The number of metamorphosed animals present in autumn before migration to Lake Huron was estimated for five cohorts, with estimates ranging from 639 to 803 thousand. The number of feeding, parasitic animals present in Lake Huron in mid summer was estimated for five cohorts, with estimates ranging from 515,000 to 2,342,000. The larger estimates later in the parasitic year suggested that animals collected and marked from sport or commercial fisheries did not survive at the same rate as unmarked animals. It is recommended that only estimates from recaptures of animals marked in the streams before migration be used until it can be established why survival of juveniles obtained from sport or commercial fisheries might be affected.

  5. 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.

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

    USGS Publications Warehouse

    Bergstedt, Roger A.; Twohey, Michael B.

    2005-01-01

    The parasitic sea lamprey (Petromyzon marinus) has been a serious pest since its introduction into the Great Lakes, where it contributed to severe imbalances in the fish communities by selectively removing large predators (Smith 1968; Christie 1974; Schneider et al.1996). Since the 1950s, restoration and maintenance of predator-prey balance has depended on the Great Lakes Fishery Commission (GLFC) sea lamprey management program. Initially, management relied primarily on stream treatments with a selective lampricide to kill larvae, on barriers to migration, and on trapping to remove potential spawners (Smith and Tibbles 1980). By the late 1970s, however, it was clear that the future of sea lamprey management lay in development of a larger array of control strategies, including more alternatives to lampricide applications (Sawyer 1980). Since then the only new alternative to chemical control to reach operational status is the release of sterilized male sea lampreys. Research on the concept began at the USGS, Hammond Bay Biological Station in Millersburg, MI (HBBS) during the 1970s (Hanson and Manion 1980). Development and evaluation continued through the 1980s, leading to the release of sterilized males in Great Lakes tributaries since 1991 (Twohey et al. 2003a). The objectives of this paper are 1) to review the implementation and evaluations of sterile-male-release technique (SMRT) as it is being applied against sea lampreys in the Great Lakes, 2) to review our current understanding of its efficacy, and 3) to identify additional research areas and topics that would increase either the efficacy of SMRT or expand its geographic potential for application.

  7. Seasonal patterns in growth, blood consumption, and effects on hosts by parasitic-phase sea lampreys in the Great Lakes: an individual-based model approach

    USGS Publications Warehouse

    Madenjian, Charles P.; Cochran, Philip A.; Bergstedt, Roger A.

    2003-01-01

    An individual-based model (IBM) was developed for sea lamprey (Petromyzon marinus) populations in the Laurentian Great Lakes. The IBM was then calibrated to observed growth, by season, for sea lampreys in northern Lake Huron under two different water temperature regimes: a regime experienced by Seneca-strain lake trout (Salvelinus namaycush) and a regime experienced by Marquettestrain lake trout. Modeling results indicated that seasonal blood consumption under the Seneca regime was very similar to that under the Marquette regime. Simulated mortality of lake trout directly due to blood removal by sea lampreys occurred at nearly twice the rate during August and September under the Marquette regime than under the Seneca regime. However, cumulative sea lamprey-induced mortality on lake trout over the entire duration of the sea lamprey's parasitic phase was only 7% higher for the Marquette regime compared with the Seneca regime. Thus, these modeling results indicated that the strain composition of the host (lake trout) population was not important in determining total number of lake trout deaths or total blood consumption attributable to the sea lamprey population, given the sea lamprey growth pattern. Regardless of water temperature regime, both blood consumption rate by sea lampreys and rate of sea lamprey-induced mortality on lake trout peaked in late October. Elevated blood consumption in late October appeared to be unrelated to changes in water temperature. The IBM approach should prove useful in optimizing control of sea lampreys in the Laurentian Great Lakes.

  8. Application of remote sensing techniques to understand the mechanisms behind the Caspian Sea lake-level fluctuations

    NASA Astrophysics Data System (ADS)

    Ozyavas, Aziz

    The Caspian Sea has exhibited significantly wide range of water-level fluctuations in its history. The primary factor for these oscillations has been overwhelmingly ascribed to climate-induced variations; geologic-related processes have been suggested to be trivial and negligible. This work processed TopexPoseidon data to estimate Lake-level heights for the Caspian Sea from the beginning of 1993 to August 2005. In order to improve the accuracy, the new Gravity Recovery and Climate Experiment orbits data, new Sea State Bias model, and Topex Microwave Radiometer drift correction were applied to the default altimetry data. The Caspian Sea hydrologic budget from 1998 to 2005 was also calculated using remote sensing and ground-based data. The National Center for Environmental Prediction Department of Energy Reanalysis 2 meteorological data provided all the variables necessary for the Penman method to estimate evaporation over the Caspian Sea. The Tropical Rainfall Measuring Mission rainfall data was utilized to estimate precipitation onto the Caspian Sea. This study reveals that lake-level changes from 1998 to 2005 are essentially controlled by meteorological factors based on the fact that a relatively minor difference between the water budget residuals and CSLL changes in the Caspian Sea. Moreover, the trend observed in the Caspian Sea lake level over the last several decades is closely correlated with Lake Van and Lake Urmia. However, the relatively higher dissimilarity present in 2000 and 2001 could imply that the Caspian Sea needs to lose some of its water to attain water balance. The two significant earthquakes with normal fault focal mechanisms and magnitudes of 6.8 and 6.5 Mw could be responsible for the Caspian Sea lake-level decline in 2000 and 2001. The contribution of submarine mud volcano eruptions to increase Caspian Sea lake level is likely to be negligible on the basis of submarine mud volcanic eruptions in 2003. Both the crustal deformation based on the

  9. Northern hemisphere climate control on the environmental dynamics in the glacial Black Sea "Lake"

    NASA Astrophysics Data System (ADS)

    Wegwerth, Antje; Kaiser, Jérôme; Dellwig, Olaf; Shumilovskikh, Lyudmila S.; Nowaczyk, Norbert R.; Arz, Helge W.

    2016-03-01

    The Marine Isotope Stage (MIS) 3 stands out due to its abrupt changes from cold and dry stadials to warm and humid interstadials, the so-called Dansgaard-Oeschger cycles that also affected temperature and rainfall in the Black Sea region. This study is based on a gravity core from the southeastern (SE) Black Sea that covers the last glacial lake stage from 64 to 20 ka BP. By using the composition of major and trace elements in the sediments, terrestrial plant-derived n-alkane flux, and Sr/Ca from benthic ostracods, we reconstruct the variability of riverine and aeolian input, salinity, and productivity in the SE Black Sea region in response to the Northern Hemisphere climate oscillations. During colder and drier stadials, the aeolian input increased relative to the riverine discharge, potentially due to southward shifted and/or stronger westerly winds and due to changes in the vegetation cover. An evaporation exceeding freshwater supply by rainfall and rivers possibly caused higher salinity and a lower lake level. The environmental status during MIS 4 and 2 is very much comparable with the stadial conditions during MIS 3. During warmer and more humid interstadials, lower salinity and presumably positive lake level changes most likely resulted from increased precipitation and river discharge. This likely increased primary productivity through an augmented nutrient supply. Lowest average salinities are suggested for the middle part of MIS 3 in response to enhanced meltwater from the disintegrating Fennoscandian Ice Sheet and/or by generally more humid conditions.

  10. 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 crassus 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.

  11. 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

  12. Mono Lake Excursion in Cored Sediment from the Eastern Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Liddicoat, Joseph; Iorio, Marina; Sagnotti, Leonardo; Incoronato, Alberto

    2013-04-01

    A search for the Laschamp and Mono Lake excursions in cored marine and lacustrine sediment younger than 50,000 years resulted in the discovery of both excursions in the Greenland Sea (73.3˚ N, 351.0˚ E, Nowaczyk and Antanow, 1997), in the North Atlantic Ocean (62.7˚ N, 222.5˚ E, Channell, 2006), in Pyramid Lake in the Lahontan Basin, NV, USA (40.1˚ N, 240.2˚ E, Benson et al., 2008), and in the Black Sea (43.2˚ N, 36.5˚ E, Nowaczyk et al., 2012). The inclination, declination, and relative field intensity during the Mono Lake Excursion (MLE) in the Black Sea sediment matches well the behaviour of the excursion in the Mono Basin, CA, in that a reduction in inclination during westerly declination is soon followed by steep positive inclination when declination is easterly, and relative field intensity increases after a low at the commencement of the excursion (Liddicoat and Coe, 1979). A large clockwise loop of Virtual Geomagnetic Poles (VGPs) at the Black Sea when followed from old to young patterns very well the VGP loop formed by the older portion of the MLE in the Mono Basin (Liddicoat and Coe, 1979). We also searched for the MLE in cored sediment from the eastern Tyrrhenian Sea (40.1˚ N, 14.7˚ E) where the age of the sediment is believed to be about 32,000 years when comparing the susceptibility in the core with the susceptibility in a nearby one that is dated by palaeomagnetic secular variation records, Carbon-14, and numerous tephra layers in the Tyrrhenian Sea sediment (Iorio et al., 2011). In the Tyrrhenian Sea core, called C1067, closely spaced samples demagnetized in an alternating field to100 mT record a shallowing of positive inclination to 48˚ that is followed by steep positive inclination of 82˚ when declination moves rapidly to the southeast. The old to young path of the VGPs in C1067 forms a narrow counter-clockwise loop that reaches 30.3˚ N, 30.8˚ E and that is centered at about 55˚ N, 15˚ E. Although descending to a latitude that is

  13. The sources and evolution of sulfur in the hypersaline Lake Lisan (paleo-Dead Sea)

    NASA Astrophysics Data System (ADS)

    Torfstein, Adi; Gavrieli, Ittai; Stein, Mordechai

    2005-07-01

    δ34S values in gypsum are used to evaluate the fate of sulfur in the hypersaline Lake Lisan, the late Pleistocene precursor of the Dead Sea (70-14 ka BP), and applied as a paleo-limnological tracer. The Ca-chloride Lake Lisan evolved through meromictic periods characterized by precipitation of authigenic aragonite and holomictic episodes characterized by enhanced gypsum precipitation. The lake deposited two major gypsum units: the "Lower Gypsum unit" (deposited at ˜56 ka) showing δ34S values of 18-20‰, and the "Upper Gypsum unit" (deposited at 17 ka) displaying significantly higher δ34S values of 26-28‰. Laminated and disseminated gypsum, residing within the aragonite, exhibit δ34S values in the range of - 26‰ to 1‰. The isotopic composition of the gypsum was dictated by freshwater sulfate input that replenished the upper layer of the lake (the mixolimnion), bacterial sulfate reduction (BSR) that occurred under the anoxic conditions of the lower brine (the monimolimnion), and mixing between these two layers. During meromictic periods, the sulfate reservoir in the lower brine was replenished by precipitation of gypsum from the upper layer, and its subsequent dissolution due to sulfate deficiency induced by BSR activity. This process describes a "sulfur pump" mechanism and its effect on δ34S in the water can be modeled by a modified Rayleigh distillation equation. Steady state δ34S values (˜40‰) were reached in the lower brine after long meromictic periods. Following overturn episodes, induced by diminishing freshwater input and lake level decline, large quantities of δ34S enriched gypsum precipitated. The negative δ34S values in laminated and disseminated gypsum provide evidence for BSR activity in the lower brine that removed isotopically depleted sulfides from the water column, causing significant isotopic enrichment of remaining sulfate. Following the lake desiccation, the sediments were exposed and the latter sulfides oxidized and re

  14. Transformation of the Lake Ladoga-Baltic Sea water connection during the Holocene

    NASA Astrophysics Data System (ADS)

    Subetto, D.; Kuznetsov, D.; Ludikova, A.; Sapelko, T.; Averichkin, O.

    2009-04-01

    1. In this presentation we will present results of complex paleolimnological and archeological studies several lakes in the Karelian Isthmus, NW Russia, located along the former Ladoga-Baltic water-system connection. Complementary field expeditions were organized in 2007 and 2008 in order to core lakes Volojarvi, Makarovskoye, Lamskoye, Uzlovoye and a lake on the Isl.Puutsaari, Northern Ladoga. 2. The ancient water connection between Lake Ladoga and the Baltic in the northern lowland of the Karelian Isthmus has been originated after the ice retreating ca 14,000-12,000 cal BP. At that time, until the catastrophic dropping of the Baltic Ice Lake (BIL) water-level happened ca 11,500 cal BP, Lake Ladoga was a deep easternmost bay of the BIL. During the BIL stage the highest shoreline reached c. 50-60 m a.s.l. in the northern part of the Karelian Isthmus. All studied lakes were flooded the BIL waters. Varved-type clay sediments were formed at that time 3. Arctic climatic and environmental conditions with stagnant ice/permafrost and sparse shrub, herb and grass vegetation on barren soils characterized the central highland of the Karelian Isthmus prior to 12,650 cal yrs BP. Steppe-tundra and cold, dry conditions are inferred between 12,650-11,200/11,000 cal yrs BP. 4. After 11,500 cal BP a straight/river existed in the northern part of the Karelian Isthmus during ca 7000 years. 5. During the Yoldia Sea regression of the Baltic (11500-11 000 cal. BP) Lake Ladoga was re-connected with the Baltic. Water level of Lake Ladoga and lakes in its basin was dropped. The vegetation was arctic tundra with sparse vegetation, which made the soils susceptible to erosion as reflected by the silty clayey sediments in Lake Ladoga. Most of the studied lakes were isolated. 6. The earliest evidence of human settlement in north-eastern Baltic Area is attested at Antrea-Korpilahti (11,200-10,250 cal BP) where artifacts were found in the deposits of a channel between the Baltic and the Ladoga

  15. Selecting Great Lakes streams for lampricide treatment based on larval sea lamprey surveys

    USGS Publications Warehouse

    Christie, Gavin C.; Adams, Jean V.; Steeves, Todd B.; Slade, Jeffrey W.; Cuddy, Douglas W.; Fodale, Michael F.; Young, Robert J.; Kuc, Miroslaw; Jones, Michael L.

    2003-01-01

    The Empiric Stream Treatment Ranking (ESTR) system is a data-driven, model-based, decision tool for selecting Great Lakes streams for treatment with lampricide, based on estimates from larval sea lamprey (Petromyzon marinus) surveys conducted throughout the basin. The 2000 ESTR system was described and applied to larval assessment surveys conducted from 1996 to 1999. A comparative analysis of stream survey and selection data was conducted and improvements to the stream selection process were recommended. Streams were selected for treatment based on treatment cost, predicted treatment effectiveness, and the projected number of juvenile sea lampreys produced. On average, lampricide treatments were applied annually to 49 streams with 1,075 ha of larval habitat, killing 15 million larval and 514,000 juvenile sea lampreys at a total cost of $5.3 million, and marginal and mean costs of $85 and $10 per juvenile killed. The numbers of juvenile sea lampreys killed for given treatment costs showed a pattern of diminishing returns with increasing investment. Of the streams selected for treatment, those with > 14 ha of larval habitat targeted 73% of the juvenile sea lampreys for 60% of the treatment cost. Suggested improvements to the ESTR system were to improve accuracy and precision of model estimates, account for uncertainty in estimates, include all potentially productive streams in the process (not just those surveyed in the current year), consider the value of all larvae killed during treatment (not just those predicted to metamorphose the following year), use lake-specific estimates of damage, and establish formal suppression targets.

  16. 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

    2013-12-19

    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.

  17. 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.

  18. 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 (r2 = 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 predationL 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, andM 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.Key words: lake trout, sea lamprey, lamprey control, mortality, predation, Lake Superior, fishery, management

  19. 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 reduc-stertion 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.

  20. Frozen Hydrocarbon Ponds on Titan: Implications for Titan’s Lakes and Seas

    NASA Astrophysics Data System (ADS)

    Soderblom, Jason M.; Barnes, Jason W.; Brown, Robert H.; Hayes, Alexander G.; Perry, Jason E.; Soderblom, Laurence A.; Turtle, Elizabeth P.

    2014-11-01

    Cassini Imaging Science Subsystem (ISS) observations have detected widespread darkening of Titan’s surface believed to be the result of rainfall: in 2005 at Arrakis Planitia, near Titan’s south pole (Turtle et al., 2009, GRL 36, L02204), and in 2009 in Titan’s tropics (Turtle et al., 2011, Science 331, 1414-1417). Cassini Visual and Infrared Mapping Spectrometer (VIMS) and ISS observations revealed that, following the tropics storm, the albedo of the wetted surfaces increased, beyond even their original albedo, then slowly faded back to a pre-rain brightness over ~10 months (Barnes et al., 2013, Planet. Sci. 2, 1). Herein we report on combined analysis of Cassini VIMS, Synthetic Aperture Radar (SAR), and ISS observations of Arrakis Planitia acquired in the years following the 2005 precipitation event. The low-albedo surface (observed in 2005 ISS images) correlates with local topography (inferred from 2008 SAR data), consistent with a liquid that has pooled on the surface. Like the equatorial event, the low-albedo surface at Arrakis Planitia is observed in VIMS data acquired from 2007 to 2009 to increase in albedo. Unlike the tropics event, however, four years after the initial precipitation event (more than 2 years after the increased albedo was first observed), these south-polar regions were still bright compared to their pre-precipitation albedo. The combined results support the hypothesis that hydrocarbons rained onto Titan’s surface and subsequently froze. Furthermore, because Titan's lakes and seas are almost certainly liquid, our results imply that some mechanism is preventing Titan's lakes and seas from freezing - one obvious hypothesis is that Titan’s lakes and seas differ in composition from Titan’s presumed methane-rich rain (likely the result of the concentration of minor constituents).

  1. Towards More Realistic Simulation of Air-Sea Interaction over Lakes on Titan

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot; Soto, Alejandro

    2016-06-01

    The exchange of methane between the atmosphere and surface liquid reservoirs dominates the short time-scale methanological cycle. In this study, previous two-dimensional simulations of the exchange of methane vapor, sensible heat and momentum between the atmosphere and lakes are updated with the inclusion of radiative forcing and extended to three dimensions, including the introduction of realistic coastlines. Previous studies of Titan's air-sea exchange in two dimensions suggested that the exchange process was self-limiting. Evaporation from lakes produced a shallow but extremely stable marine layer that suppressed turbulent exchange. Furthermore, the circulation associated with the higher buoyancy of methane-rich atmosphere over the lake was offset by the oppositely directed thermal sea breeze circulation, which muted the mean wind. Two major weaknesses of this previous work were the lack of radiative forcing and the imposition of two dimensionality that limited the full range of dynamical solutions. Based on early theoretical studies, it was thought that magnitude of turbulent energy flux exchanges would be much larger than radiative fluxes, thereby justifying the neglect of radiation, but the two-dimensional simulations indicated that this was not a valid assumption. The dynamical limitations of two-dimensional simulations are well known. Vorticity stretching (i.e., circulation intensification through vertical motion) is not possible and it is also not possible to produce dynamically balanced gradient wind-type circulations. As well, the irregular shape of a realistic coastline cannot be expressed in two dimensions, and these realistic structures will generally induce complex convergence and divergence circulations in the atmosphere. The impact of radiative forcing and the addition of the third dimension on the air-sea exchange are presented.

  2. Sounding Titan's Lakes and Seas: Bathymetry, Composition, and Role in the Hydrologic Cycle

    NASA Astrophysics Data System (ADS)

    Hayes, Alexander; Mastrogiuseppe, Marco; Lunine, Jonathan I.; Poggiali, Valerio; Lorenz, Ralph; Le Gall, Alice; Mitchell, Karl L.; Cassini RADAR Science Team

    2016-10-01

    One of the most surprising discoveries of the Cassini Solstice Mission is the microwave transparency of Titan's lakes and seas. Coherent processing of altimetry echoes acquired over Ligeia Mare in May 2013 revealed bottom reflections and allowed construction of a bathymetric profile as well as an estimation of the liquid loss tangent. Following the successful detection of subsurface echoes at Ligeia, the RADAR team organized a campaign to acquire altimetry over the remaining Mare. Altimetry over Kraken and Punga Maria were obtained in August 2014 and January 2015, respectively, and also show detectable subsurface echoes. Using new analysis techniques, subsurface returns were also recovered from data acquired over Ontario Lacus in 2008. The final Titan flyby (T126, April 2017) will acquire altimetry over several of the smaller lakes in Titan's north, permitting comparative studies between the Mare and lakes. In this presentation, we will report on the latest results from this ongoing campaign.Assuming a ternary composition of CH4, C2H6, and N2, the best-fit loss tangent at Ligeia Mare is consistent with 71% CH4, 12% C2H6, and 17% N2 by volume. The best-fit loss tangent Ontario Lacus is consistent with 47% CH4, 40% C2H6, and 13% N2. The higher loss tangent at Ontario Lacus could result from an increased abundance of more involatile hydrocarbons and/or nitriles; these species could be concentrated as a consequence of orbitally-driven insolation cycles that may have slowly transported volatile components (methane/ ethane) to the north over the past several tens of millennia. Initial analysis of Kraken and Punga Maria suggest liquid absorptivity similar to Ligeia Mare. In total, the bathymetric results suggest that the total volume of Titan's lakes and seas is >70,000 km3. If this liquid were evenly spread across the surface it would be equivalent to a global ocean depth of 1 m. This is equivalent to 300 times the mass of Earth's proven natural gas reserves. Unlike

  3. 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-μm. 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-μm map suggests that the shoreline has not evolved since 2010. The shape of the 2- μm 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-μm. Equipotential maps are built from the

  4. 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

  5. A Comparison of Eemian and Holocene Transgressions of the Baltic Sea based on the Sedimentary Record of Lake Ladoga

    NASA Astrophysics Data System (ADS)

    Delusina, I.; Andreev, A.

    2015-12-01

    Two cycles of postglacial transgressions of Baltic Sea could be recognized in the sediments of Lake Ladoga and vicinity: an Eemian (MIS 5e, ca 124-119 kya) and a Holocene with several subsequent stages: Ancylus Lake, Mastogloia Sea and Littorina Sea, starting at ca 9.5 kya BP and existing up to 4 kya BP. New data obtained from deep coring in Lake Ladoga (Andreev et al., 2014) has allowed us to re-visit an old question about the age and nature of sediments at the bottom of Lake Ladoga. The lake is east of the Baltic and provides important information about the marginal stage of Baltic Sea levels, and in particular about differences between the Eemian and Holocene transgressions. Previously Eemian marine sediments have never been found at the bottom of Lake Ladoga although they have been identified along river terraces, in small lakes and as detached lenses. The new coring reached a depth of 22 m, and found marine diatoms that might correspond to the Eemian transgression. As part of the effort to understand these fossils, we have compiled a comprehensive picture of the distribution of Eemian sediments around Lake Ladoga. There is very little published data about these deposits (Miettinen et al., 2014) so we have assembled known, but never published or published only in Russian, data. The number of unpublished marine Eemian sequences exceeds 70. They occur more frequently here than on other Baltic coasts, because of the low position of the eastern Baltic territories above the sea level. This meant that they were not destroyed by isostatic uplift, which resulted in the deposition of thicker layers of sediment than in mountainous Fennoscandia. Typical Eemian sediments comprise a black clay layer with Yoldia arctica, have a monotonous appearance and are easily distinguished from other interglacial sediments. The modern elevation of these sections implies that the elevation of the Eemian Sea could not have exceeded +17 m and probably was very uniform.The Holocene

  6. Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

    USGS Publications Warehouse

    Hansen, Michael J.; Madenjian, Charles P.; Slade, Jeffrey W.; Steeves, Todd B.; Almeida, Pedro R.; Quintella, Bernardo R.

    2016-01-01

    The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range.

  7. Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Inundation for Categories 2 and 4

    EPA Pesticide Factsheets

    The file geodatabase (fgdb) contains the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Maximum of Maximums (MOM) model for hurricane categories 2 and 4. The EPA Office of Research & Development (ORD) modified the original model from NOAA to fit the model parameters for the Buzzards Bay region. The models show storm surge extent for the Mattapoisett area and therefore the flooding area was reduced to the study area. Areas of flooding that were not connected to the main water body were removed. The files in the geodatabase are:Cat2_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 2 hurricane with 0 ft sea level riseCat4_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 4 hurricane with 0 ft sea level riseCat4_SLR4_Int_Feet_dissolve_Mattapoisett: Future Category 4 hurricane with 4 feet sea level riseThe features support the Weather Ready Mattapoisett story map, which can be accessed via the following link:https://epa.maps.arcgis.com/apps/MapJournal/index.html?appid=1ff4f1d28a254cb689334799d94b74e2

  8. A numerical study on the influence of fractured regions on lake/groundwater interaction; the Lake Kinneret (Sea of Galilee) case

    NASA Astrophysics Data System (ADS)

    Abbo, Hila; Shavit, Uri; Markel, Doron; Rimmer, Alon

    2003-12-01

    Increased lake salinity is a growing problem in arid and semi-arid regions. Operational management, which is based on a reliable hydrological understanding, has the potential to reduce the lake salinity. This is the case of the salinity in Lake Kinneret (Sea of Galilee), where saline water flows into the lake through on-shore and off-shore springs. Here, we present a time-dependent flow and transport numerical model that successfully reproduces the monitored groundwater level, discharge, and salinity of the lake springs. The model utilizes a continuum approach and describes the flow through a confined saline carbonate aquifer, which interacts with the discharge lake through fractures and faults. In particular, the model investigates the hydrology around two groups of springs, Fuliya and Tabgha, along the western shore of the lake. Based on seasonal characteristics of the springs and measured boundary conditions, the two springs groups were defined as Lake Dominated Springs (LDS, Fuliya) and Aquifer Dominated Springs (ADS, Tabgha). The models of the two groups differ from each other in the distribution of fractured regions that link between the lake and the underlying aquifers. The numerical solution shows how the fractured regions affect groundwater head, spring discharge, and spring salinity. The different behavior of the LDS and ADS was reproduced with an excellent agreement between measured and calculated patterns. Differences in salinity within a group of springs are shown to be dependent on the depth of the fractured region. It was revealed that in addition to the appropriate distribution of fractured regions some adjustment in the up-stream boundary conditions is necessary to fully reproduce the system hydrology. The model has improved our understanding and provides a prediction tool for future management strategies.

  9. (90)Sr in fish from the southern Baltic Sea, coastal lagoons and freshwater lake.

    PubMed

    Zalewska, Tamara; Saniewski, Michał; Suplińska, Maria; Rubel, Barbara

    2016-07-01

    Activity concentrations of radioactive (90)Sr were studied in four fish species: herring, flounder, sprat and cod caught in the southern Baltic Sea in two periods: 2005-2009 and 2013-2014. The study included also perch from the coastal lagoons - Vistula Lagoon and Szczcin Lagoon and a freshwater lake - Żarnowieckie Lake as well as additional lake species: pike and bream. (90)Sr activity concentrations were compared in relation to species and to particular tissue: muscle, whole fish (eviscerated) and bones. In 2014, in the Baltic, the maximal (90)Sr concentrations were found in fishbones: herring - 0.39 Bq kg(-1) w.w., cod - 0.48 Bq kg(-1) w.w., and flounder - 0.54 Bq kg(-1) w.w. In the whole fish the maximal concentrations were found in flounder - 0.16 Bq kg(-1) w.w. and cod - 0.15 Bq kg(-1) w.w., while in herring - 0.022 Bq kg(-1) w.w. and sprat - 0.026 Bq kg(-1) w.w. they stayed at lower level. Relatively high (90)Sr concentrations were detected in whole fish from freshwater Lake Żarnowieckie: perch - 0.054 Bq kg(-1) w.w., pike - 0.062 Bq kg(-1) w.w. and bream - 0.140 Bq kg(-1) w.w. Concentration ratio (CR) determined for particular fish tissues and for whole eviscerated fish in relation to (90)Sr concentrations in seawater and lake water were showing significant variability unlike the corresponding (137)Cs concentration ratios which are stable and specific for fish species. The study corroborates with the conviction of the growing role of (90)Sr in the overall radioactivity in the southern Baltic Sea as compared to (137)Cs.

  10. Stromatolites in caves of the Dead Sea Fault Escarpment: implications to latest Pleistocene lake levels and tectonic subsidence

    NASA Astrophysics Data System (ADS)

    Lisker, Sorin; Vaks, Anton; Bar-Matthews, Miryam; Porat, Roi; Frumkin, Amos

    2009-01-01

    A varied assemblage of algal stromatolites was encountered in caves along the northern section of the Dead Sea Fault Escarpment. The caves are situated at the lower part of the escarpment at altitudes -310 to -188 m relative to mean sea level (m.s.l.), i.e. ca 110-230 m above the present Dead Sea level. The cave stromatolites are mainly composed of aragonite yielding U-Th ages of ˜75-17 ka. The altitude, mineralogy and ages, as well as comparison with previously documented stromatolite outcrops in the area, ascribe the cave stromatolites to the aragonite-precipitating hypersaline Lake Lisan—the Late Pleistocene predecessor of the Dead Sea. The stromatolites are used as a lake level gauge, based on the algae being reliant upon the light of the upper water layer. Preservation of the original structure and aragonite mineralogy of the stromatolites, suggests a closed system regarding the radioactive elements, enabling reliable U-Th dating. A curve of Lake Lisan levels is constructed based on the stromatolite ages and cave elevations. The following points are noted: (1) Lake levels of -247 m relative to m.s.l., are recorded at ˜75-72.5 ka; (2) relatively high lake levels above -220 m relative to m.s.l., are achieved at ˜41.5 ka, and are still recorded at ˜17 ka; (3) the peak level is -188 m relative to m.s.l., at ˜35.5-29.5 ka. These results indicate lake stands up to 80 m higher than previously accepted, for large parts of the Lake Lisan time span. This difference is explained by tectonic subsidence of up to 2.2 m/ka within the Dead Sea depression since the latest Pleistocene. This subsidence rate is in the same order of magnitude with previously calculated subsidence rates for the Dead Sea depression [Begin, Z.B., Zilberman, E., 1997. Main Stages and Rate of the Relief Development in Israel. Geological Survey of Israel report, Jerusalem]. Unlike previous Lake Lisan level estimations, the new curve is measured at the relatively stable shoulders of the Dead Sea

  11. 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.

  12. Changing climate and sea level alter Hg mobility at Lake Tulane, Florida, U.S.

    PubMed

    Jacobson, G L; Norton, S A; Grimm, E C; Edgar, T

    2012-11-06

    Between 45,000 cal years BP and the beginning of the Holocene, the accumulation rate for Hg in sediments of Lake Tulane, Florida ranged from ≈2 to 10 μg m(-2) yr(-1), compared with 53 μg Hg m(-2) yr(-1) in the 1985-1990 period of anthropogenic input. The locality experienced regional draw-down of the water table during the Wisconsinan glaciation, which lowered global sea level by nearly 130 m. Natural atmospheric deposition of Hg to the surrounding area resulted in long-term (ca. 100,000 years) sequestration of this atmospheric flux of Hg, primarily by adsorption in the oxic Al- and Fe-hydroxide-rich sandy subsoil. Global sea level rise during deglaciation led to a rising regional water table, flooding the oxidized soils surrounding Tulane. Iron and adsorbed Hg were mobilized by reductive dissolution and transported by groundwater flow to Lake Tulane and ultimately to the accumulating sediment. The accumulation rate of Hg (and Fe) increased rapidly about 16,000 cal years BP, peaked at nearly 60 μg Hg m(-2) yr(-1) ca. 13,000-14,000 cal years BP, declined sharply during the Younger Dryas, and then increased sharply to a second 60 μg Hg m(-2) yr(-1) peak about 5000 cal years BP. Thereafter, it declined nearly to background by 900 cal years BP. In similar geologic situations, rapid modern sea level rise will initiate this process globally, and may mobilize large accumulations of Hg and lesser amounts of As, and other redox sensitive metals to groundwater and surface water.

  13. 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 δ18O 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.

  14. Emerging pollutants in the North Sea in comparison to Lake Ontario, Canada, data.

    PubMed

    Andresen, Jens Arne; Muir, Derek; Ueno, Daisuke; Darling, Colin; Theobald, Norbert; Bester, Kai

    2007-06-01

    In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.

  15. [Book Review] The Dead Sea, the lake and its setting, edited by T. Niemi, Z. Ben-Avraham, J. Gat

    USGS Publications Warehouse

    ten Brink, Uri

    1998-01-01

    Review of The Dead Sea, the Lake and its Setting. Tina M. Niemi, Zvi Ben-Avraham, and Joel R. Gat (Editors). Oxford Monographs on Geology and Geophysics No. 36. Oxford University Press, N.Y. 286 pp. ISBN 0-19-508703-8, 1997. $75.

  16. 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…

  17. A new method of quantifying discharge of small rivers into lakes and inland seas

    NASA Astrophysics Data System (ADS)

    Osadchiev, Alexander; Zavialov, Peter

    2014-05-01

    Continental discharge is an important component of the global hydrological cycle, providing the majority of the input part of the ocean water balance. Buoyant inflow usually causes surface density stratification at the large shelf areas, and plays a significant role in physical, chemical, and biological processes there that is especially important for the lakes and inland seas. Although there is a lack of discharge data for most of rivers in a global scale. Regular direct measurements of discharge are performed only for a relatively small number of rivers, generally the biggest ones or ones that flow through densely populated areas. Within this problem an indirect method of assuming a volume of river discharge was developed. The general idea of the method is the following. Firstly, the spatial surface spread of the plume generated by the considered river discharge is identified using high resolution satellite imagery of the coastal zone adjacent to the river estuary. Secondly, a series of numerical simulations of the river runoff spread is performed under various prescribed external forcing conditions which include the discharge rate. Varying forcing conditions we iteratively improve the accordance between simulated and observed river plumes therefore consequentially specifying the value of river discharge. The developed method was applied and validated against in situ date for several rivers feeding the Black Sea. Practical importance of this work consists in the fact, that the suggested method is an alternative for the expensive and laborious direct measurements of the river discharge, which are used nowadays.

  18. Lithosphere-biosphere interaction at a shallow-sea hydrothermal vent site; Hot Lake, Panarea, Italy

    NASA Astrophysics Data System (ADS)

    Huang, Chia-I.; Amann, Rudolf; Amend, Jan P.; Bach, Wolfgang; Brunner, Benjamin; Meyerdierks, Anke; Price, Roy E.; Schubotz, Florence; Summons, Roger; Wenzhöfer, Frank

    2010-05-01

    Deep-Sea hydrothermal systems are unique habitats for microbial life with primary production based on chemosynthesis and are considered to be windows to the subsurface biosphere. It is often overlooked, however, that their far more accessible shallow-sea counterparts are also valuable targets to study the effects of hydrothermal activity on geology, seawater chemistry and finally, on microbial life. Such an area of shallow marine hydrothermal venting is observed approximately 2.5 km east of Panarea Island (Sicily, Italy). This system is characterized by fluid temperatures of up to 135° C, gas emissions dominated by CO2 and precipitation of elemental sulfur on the seafloor. In an interdisciplinary project to investigate the influence of geofuels on marine microbiota, sediment cores and pore fluids were sampled for geological and geochemical analyses. An attempt was made to link these geochemical data with a characterization of the microbial community. One of the investigated sites (Lago Caldo, Hot Lake) is an oval-shaped (~10 by 6 meters) shallow (~2.5 m deep) depression covered by elemental sulfur. The sediments in this depression are strongly affected by hydrothermal activity: the pH of pore fluids is in a range between 5 and 6; the salinity is approximately two times higher than seawater. In situ temperatures of 36° C and 74° C (10 cm sediment depth) at two different locations within Hot Lake indicate variability in hydrothermal flux. The sediment surface layer is anoxic, and with increasing depth from the sediment-water interface, sulfate concentrations decrease from ~30 mM to less than 10 mM, whereas sulfide concentrations increase from less than 50 μm to ~1000 μm at 25 cm sediment depth, thus suggesting a higher potential for energy gain based on sulfur disequilibrium. As indicated by the variability in the sediment temperatures at 10 cm, fluid fluxes and mixing with seawater is not found to be uniform at Hot Lake. This is reflected in variability of the

  19. 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

  20. Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

    PubMed

    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.

  1. 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 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.

  2. 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

  3. Climate-induced variations in lake levels: A mechanism for short-term sea level change during non-glacial times

    SciTech Connect

    Jacobs, D. ); Sahagian, D. . Dept of Geological Sciences)

    1992-01-01

    Variations in insolation due to periodic orbital parameters can cause climatic changes and associated variations in the intensity of monsoonal circulation. This can lead to significant variations in the levels of internally draining lakes on timescales of 10,000 to 100,000 years in regions affected by the monsoon (20,000 years for orbital precession). These variations may be responsible for small scale (few meters) eustatic sea level changes in an ice-free Earth, and may contribute to sea level changes in the presence of ice as well. The authors have estimated the volume of empty present lake basins in the regions of Asia and North Africa influenced by the monsoon. The surface water volume alone of these basins is equivalent to a two meter difference in sea level, but is considerably augmented by groundwater associated with an increase in lake level. The lake variation mechanism for sea level change has its basis in the Quaternary record of climate change and associated explanatory models. However, the argument also applies to earlier, non-glacial periods of geologic time. Clear evidence for the presence of ice in the Triassic is lacking. However, there is evidence for short-term periodic fluctuations of lake levels as well as sea level during that time. These sea level changes, as well as those in the Devonian, Jurassic, and Cretaceous, may be driven by periodic fluctuation in lacustrine and groundwater storage resulting from orbitally forced changes in monsoon intensity, even in the absence of significant glacial ice.

  4. Chemical Characterization of Lipophilic Constituents in the Skin of Migratory Adult Sea Lamprey from the Great Lakes Region

    PubMed Central

    Dissanayake, Amila A.; Wagner, C. Michael; Nair, Muraleedharan G.

    2016-01-01

    The sea lamprey (Petromzons marinus) is an invasive ectoparasite of large-bodied fishes that adversely affects the fishing industry and ecology of the Laurentian Great Lakes. Lipid content in the whole sea lamprey and muscles, liver and kidney of metamorphosing larval stages has been reported. Similarly, the fatty acid profile of the rope tissues of sexually-mature male sea lampreys has also been reported. The average body weight of a sub-adult migratory sea lamprey is 250 g, which includes 14.4% skin (36 g). Our preliminary extraction data of an adult sea lamprey skin revealed that it contained approximately 8.5% of lipophilic compounds. Lamprey skin is home to a naturally aversive compound (an alarm cue) that is being developed into a repellent for use in pest management. As part of an ongoing investigation to identify the chemical structure of the sea lamprey alarm cue, we extracted the skin with water and methanol, respectively. The methanolic extract (1.55%) contained exclusively lipophilic compounds and did not include the alarm cue. We chemically characterized all compounds present in the methanolic extract as cholesterol esters (CE), tri- and di-glycerides (TG and DG), cholesterol, free fatty acids (FFA) and minor amounts of plasticizers. The free fatty acids fraction was composed of saturated (41.8%), monounsaturated (40.7%) and polyunsaturated (17.4%) fatty acids, respectively. The plasticizers characterized were phthalate and benzoate and found to be 0.95 mg and 2.54 mg, respectively, per adult sea lamprey skin. This is the first report of the chemical characterization of all the lipophilic constituents in the skin of sub-adult migratory sea lamprey. The CEs isolated and characterized from sea lamprey skin are also for the first time. PMID:27992570

  5. Evaluating harvest-based control of invasive fish with telemetry: performance of sea lamprey traps in the Great Lakes.

    PubMed

    Holbrook, Christopher M; Bergstedt, Roger A; Barber, Jessica; Bravener, Gale A; Jones, Michael L; Krueger, Charles C

    2016-09-01

    Physical removal (e.g., harvest via traps or nets) of mature individuals may be a cost-effective or socially acceptable alternative to chemical control strategies for invasive species, but requires knowledge of the spatial distribution of a population over time. We used acoustic telemetry to determine the current and possible future role of traps to control and assess invasive sea lampreys, Petromyzon marinus, in the St. Marys River, the connecting channel between Lake Superior and Lake Huron. Exploitation rates (i.e., fractions of an adult sea lamprey population removed by traps) at two upstream locations were compared among three years and two points of entry to the system. Telemetry receivers throughout the drainage allowed trap performance (exploitation rate) to be partitioned into two components: proportion of migrating sea lampreys that visited trap sites (availability) and proportion of available sea lampreys that were caught by traps (local trap efficiency). Estimated exploitation rates were well below those needed to provide population control in the absence of lampricides and were limited by availability and local trap efficiency. Local trap efficiency estimates for acoustic-tagged sea lampreys were lower than analogous estimates regularly obtained using traditional mark-recapture methods, suggesting that abundance had been previously underestimated. Results suggested major changes would be required to substantially increase catch, including improvements to existing traps, installation of new traps, or other modifications to attract and retain more sea lampreys. This case study also shows how bias associated with telemetry tags can be estimated and incorporated in models to improve inferences about parameters that are directly relevant to fishery management.

  6. Evaluating harvest-based control of invasive fish with telemetry: Performance of sea lamprey traps in the Great Lakes

    USGS Publications Warehouse

    Holbrook, Christopher; Bergstedt, Roger A.; Barber, Jessica M.; Bravener, Gale A; Jones, Michael L.; Krueger, Charles C.

    2016-01-01

    Physical removal (e.g., harvest via traps or nets) of mature individuals may be a cost-effective or socially acceptable alternative to chemical control strategies for invasive species, but requires knowledge of the spatial distribution of a population over time. We used acoustic telemetry to determine the current and possible future role of traps to control and assess invasive sea lampreys, Petromyzon marinus, in the St. Marys River, the connecting channel between Lake Superior and Lake Huron. Exploitation rates (i.e., fractions of an adult sea lamprey population removed by traps) at two upstream locations were compared among three years and two points of entry to the system. Telemetry receivers throughout the drainage allowed trap performance (exploitation rate) to be partitioned into two components: proportion of migrating sea lampreys that visited trap sites (availability) and proportion of available sea lampreys that were caught by traps (local trap efficiency). Estimated exploitation rates were well below those needed to provide population control in the absence of lampricides and were limited by availability and local trap efficiency. Local trap efficiency estimates for acoustic-tagged sea lampreys were lower than analogous estimates regularly obtained using traditional mark–recapture methods, suggesting that abundance had been previously underestimated. Results suggested major changes would be required to substantially increase catch, including improvements to existing traps, installation of new traps, or other modifications to attract and retain more sea lampreys. This case study also shows how bias associated with telemetry tags can be estimated and incorporated in models to improve inferences about parameters that are directly relevant to fishery management.

  7. Concentrations of organotin compounds in various fish species in the Finnish lake waters and Finnish coast of the Baltic Sea.

    PubMed

    Rantakokko, Panu; Hallikainen, Anja; Airaksinen, Riikka; Vuorinen, Pekka J; Lappalainen, Antti; Mannio, Jaakko; Vartiainen, Terttu

    2010-05-15

    Organotin compounds (OTCs) leaching from the antifouling paints used in boats and ships have contaminated many water areas worldwide. The purpose of this study was to obtain a general view of the organotin contamination in fish in Finnish lake areas and Finnish coast of the Baltic Sea using perch as the main indicator species. Perch sampling covered areas presumed as less contaminated and areas suspected as more contaminated. Besides perch, 12 other species were sampled from sites presumed as less contaminated. OTCs measured were mono-, di- and tributyltin, mono-, di-, and triphenyltin and dioctyltin. The sum concentration of OTCs (SigmaOTCs) in perch in the least contaminated areas of the Baltic Sea were around 20 ng/g fresh weight (fw) and less than 10 ng/g fw in lake areas. In heavily contaminated areas of the Baltic Sea 150-500 ng/g fw in perch were detected. In lake areas the maximum SigmaOTCs in perch was only 30 ng/g fw. With regard to the other species in the Baltic Sea, salmon, sprat, flounder, whitefish, vendace and lamprey contained low concentrations (SigmaOTCs mainly less than 20 ng/g fw), whereas in pike, pike-perch, burbot and bream concentrations were higher. SigmaOTCs in lake fish were generally lower than in the Baltic Sea. In a distance gradient study, SigmaOTCs in perch decreased quickly from nearly 200 ng/g fw at a contaminated harbor area to 35 ng/g fw during a distance of 5 km. Further decrease was slower and reached 15 ng/g fw at 100 km. In a size dependence study triphenyltin showed better correlation with the fish length than tributyltin for all species studied, i.e. for perch (0.16 vs 0.26), pike-perch (0.13 vs 0.24) and roach (0.46 vs 0.80). High correlation for roach may be partly explained by smaller number of samples collected and small length range.

  8. Carbon stored in peatlands formed by terrestrialization: the importance of buried lake sediments

    NASA Astrophysics Data System (ADS)

    Talbot, J.

    2015-12-01

    A lot of efforts have been made over the last few decades to quantify the amount of carbon stored in soils, including in peat-producing systems. Estimates of soil carbon storage at the landscape scale has to take into account all buried carbon pools, including deep-buried lake sediments found under many peatlands that formed by terrestrialization. To illustrate the importance of buried lake sediments in the overall carbon storage of a peatland site, we studied a small peat swamp located in Gatineau Park (Quebec, Canada), the Folly peatland (45°27'18.12"N 75°46'57.38''W). This 7 ha peatland developed from a small lake that appeared after the postglacial Champlain Sea receded from the region, about 12 200 years ago. Its development followed a classical terrestrialization sequence and its hydrology has been stable since peat inception. A profile of over 8.5 m of organic matter was collected at the site, of which 2.5 m is peat and the rest is composed of lake sediments (gyttja). With the exception of a few tephra layers, the organic matter content exceeds 75 % of dry weight for the entire profile. Although it constitutes only 30 % of the profile depth, peat contains 48 % of the buried carbon because of its higher bulk density, and peat carbon accumulated at a rate of 88 g C m-2 yr-1. Overall, the site carbon density (including buried lake sediments) is 172 kg C m-2, a value comparable to the carbon density of many peatlands with much deeper peat profiles. The implications of these findings are discussed in the context of global peatland carbon inventories and peatland biogeochemistry.

  9. Spectroscopic study of the microbial community in chemocline zones of relic meromictic lakes separating from the White Sea

    NASA Astrophysics Data System (ADS)

    Kharcheva, Anastasia V.; Krasnova, Elena D.; Voronov, Dmitry A.; Patsaeva, Svetlana V.

    2015-03-01

    As a result of a recent years study on the Karelia shore of the White Sea more than ten relict lakes in different stages of separation from the sea have been discovered. Five of them are located close to the Nikolai Pertsov White Sea Biological Station of Moscow State University. Such separated lakes are interesting to explore for their firm vertical stratification. Water layers differ not only by temperature, salinity and other physic and chemical characteristics and optical properties, but also by ibhabiting microorganisms and by the quality of dissolved organic matter. To study phototropic organisms in water sampled from different depths we used spectroscopic techniques. Identification of the main bands in the absorption and fluorescence spectra showed that there are two main groups of photosynthetic organisms in the redox zone (chemocline): unicellular algae containing chlorophyll a and green sulfur bacteria with bacteriochlorophylls c, d, e. Spectral data were compared with physical and chemical characteristics of the water layer (temperature, salinity, pH, dissolved oxygen and sunlight illumination at certain depth). It gave an opportunity to compare vertical profiles of oxygen and hydrogen sulphide concentration with the number and distribution of oxygenic and anoxygenic phototrophic microorganisms. Maximum abundance of both algae and green sulfur bacteria were achieved within the redox zone. Typical thickness of the layer with the highest concentration of microorganisms did not exceed 10-20 cm.

  10. Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy.

    PubMed

    Bindler, Richard; Renberg, Ingemar; Rydberg, Johan; Andrén, Thomas

    2009-07-01

    Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren--Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.

  11. Coastal lake sediments from the southern Cape, South Africa - Implications for sea level and climate variations during the Holocene

    NASA Astrophysics Data System (ADS)

    Wündsch, M.; Haberzettl, T.; Kirsten, K. L.; Meschner, S.; Frenzel, P.; Baade, J.; Daut, G.; Mäusbacher, R.; Kasper, T.; Quick, L. J.; Meadows, M. E.; Zabel, M.

    2015-12-01

    Within the RAIN project (Regional Archives for Integrated iNvestigations) interdisciplinary investigations on climate evolution and environmental change in southern Africa during the Late Quaternary are being conducted. For this purpose, spatial and temporal variations of the three major rainfall zones covering South Africa (winter-, summer- and year-round rainfall zone) are studied using both marine and terrestrial archives. Here we present results inferred from sediment records from lakes Groenvlei and Eilandvlei located on the southern Cape coast within the year-round rainfall zone. From Eilandvlei, a brackish lake that is connected to the Indian Ocean via an estuary, a 30.5 m sediment core was recovered. Reservoir-corrected radiocarbon ages reveal a continuous sedimentation and a maximum age of about 8,900 cal BP. This ultra-high-resolution record of environmental change during the Holocene represents a unique discovery for entire southern Africa. Geochemical data reveal different phases of marine and terrestrial sediment deposition throughout the covered time span. Hence, this record reflects changes in sea level, but also variations in terrestrial sediment transport and thus changing climatic conditions. The sediment core from Groenvlei, which today is isolated from the Indian Ocean, covers the past 4,200 cal BP. Sediments from this lake are predominantly composed of autochthonous carbonates. Mineralogical investigations reveal alternating deposition of calcite and aragonite/dolomite, pointing to variable Mg/Ca ratios and thus variations in lake water salinity. These changes can be linked to sea level variations as well as to changes in the precipitation/evaporation balance, and hence climate. Based on these results, the Groenvlei record reveals a decreasing marine influence and a trend from generally drier to wetter conditions within the last 4,200 yrs. Moreover, several layers of enhanced allochtonous input were detected in this record, which can be

  12. Experimental evaluation of atmospheric effects on radiometric measurements using the EREP of Skylab. [Salton Sea and Great Salt Lake

    NASA Technical Reports Server (NTRS)

    Chang, D. T. (Principal Investigator); Isaacs, R. G.

    1975-01-01

    The author has identified the following significant results. Test sites were located near the Great Salt Lake and the Salton Sea. Calculations were performed for a set of atmospheric models corresponding to the test sites, in addition to standard models for summer and winter midlatitude atmospheres with respective integrated water vapor amount of 2.4 g/sq cm and 0.9 g/sq cm. Each atmosphere was found to contain an average amount of continental aerosol. Computations were valid for high solar elevation angles. Atmospheric attenuation quantities were computed in addition to simulated EREP S192 radiances.

  13. Sea level rise and inundation of island interiors: Assessing impacts of lake formation and evaporation on water resources in arid climates

    NASA Astrophysics Data System (ADS)

    Gulley, J. D.; Mayer, A. S.; Martin, J. B.; Bedekar, V.

    2016-09-01

    Coasts of many low-lying islands will be inundated should sea level rise by 1 m by 2100 as projected, thereby decreasing water resources through aquifer salinization. A lesser known impact occurs if rising sea level elevates water tables above interior topographic lows to form lakes. Impacts of lake formation on water resources, however, remain unquantified. Here we use hydrological models, based on islands in the Bahamian archipelago, to demonstrate that on islands with negative water budgets, evaporation following lake inundation can cause more than twice the loss of fresh groundwater resources relative to an equivalent amount of coastal inundation. This result implies that in dry climates, low-lying islands with inland depressions could face substantially greater threats to their water resources from sea level rise than previously considered.

  14. Effects of sea lamprey (Petromyzon marinus) control in the Great Lakes on aquatic plants, invertebrates and amphibians

    USGS Publications Warehouse

    Gilderhus, P.A.; Johnson, B.G.H.

    1980-01-01

    The chemicals 3-trifluoromethyl-4-nitrophenol (TFM) or a combination of TFM and 2a??,5-dichloro-4a??-nitrosalicylanilide (Bayer 73) have been used to control the sea lamprey (Petromyzon marinus) in the Great Lakes for about 20 yr. These chemicals cause some mortalities of Oligochaeta and Hirudinea, immature forms of Ephemeroptera (Hexagenia sp.), and certain Trichoptera, Simuliidae, and Amphibia (Necturus sp.). The combination of TFM and Bayer 73 may affect some Pelecypoda and Gastropoda, but its overall effects on invertebrates are probably less than those of TFM alone. Granular Bayer 73 is likely to induce mortalities among oligochaetes, microcrustaceans, chironomids, and pelecypods. No evidence exists that the lampricides have caused the catastrophic decline or disappearance of any species. The overall impact of chemical control of sea lampreys on aquatic communities has been minor compared with the benefits derived.

  15. Lake and sea populations of Mysis relicta (Crustacea, Mysida) with different visual-pigment absorbance spectra use the same A1 chromophore.

    PubMed

    Belikov, Nikolai; Yakovleva, Marina; Feldman, Tatiana; Demina, Olga; Khodonov, Andrei; Lindström, Magnus; Donner, Kristian; Ostrovsky, Mikhail

    2014-01-01

    Glacial-relict species of the genus Mysis (opossum shrimps) inhabiting both fresh-water lakes and brackish sea waters in northern Europe show a consistent lake/sea dichotomy in eye spectral sensitivity. The absorbance peak (λmax) recorded by microspectrophotometry in isolated rhabdoms is invariably 20-30 nm red-shifted in "lake" compared with "sea" populations. The dichotomy holds across species, major opsin lineages and light environments. Chromophore exchange from A1 to A2 (retinal → 3,4-didehydroretinal) is a well-known mechanism for red-shifting visual pigments depending on environmental conditions or stages of life history, present not only in fishes and amphibians, but in some crustaceans as well. We tested the hypothesis that the lake/sea dichotomy in Mysis is due to the use of different chromophores, focussing on two populations of M. relicta from, respectively, a Finnish lake and the Baltic Sea. They are genetically very similar, having been separated for less than 10 kyr, and their rhabdoms show a typical lake/sea difference in λmax (554 nm vs. 529 nm). Gene sequencing has revealed no differences translating into amino acid substitutions in the transmembrane parts of their opsins. We determined the chromophore identity (A1 or A2) in the eyes of these two populations by HPLC, using as standards pure chromophores A1 and A2 as well as extracts from bovine (A1) and goldfish (A2) retinas. We found that the visual-pigment chromophore in both populations is A1 exclusively. Thus the spectral difference between these two populations of M. relicta is not due to the use of different chromophores. We argue that this conclusion is likely to hold for all populations of M. relicta as well as its European sibling species.

  16. Relationships between lake-level changes and water and salt budgets in the Dead Sea during extreme aridities in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Kiro, Yael; Goldstein, Steven L.; Garcia-Veigas, Javier; Levy, Elan; Kushnir, Yochanan; Stein, Mordechai; Lazar, Boaz

    2017-04-01

    Thick halite intervals recovered by the Dead Sea Deep Drilling Project cores show evidence for severely arid climatic conditions in the eastern Mediterranean during the last three interglacials. In particular, the core interval corresponding to the peak of the last interglacial (Marine Isotope Stage 5e or MIS 5e) contains ∼30 m of salt over 85 m of core length, making this the driest known period in that region during the late Quaternary. This study reconstructs Dead Sea lake levels during the salt deposition intervals, based on water and salt budgets derived from the Dead Sea brine composition and the amount of salt in the core. Modern water and salt budgets indicate that halite precipitates only during declining lake levels, while the amount of dissolved Na+ and Cl- accumulates during wetter intervals. Based on the compositions of Dead Sea brines from pore waters and halite fluid inclusions, we estimate that ∼12-16 cm of halite precipitated per meter of lake-level drop. During periods of halite precipitation, the Mg2+ concentration increases and the Na+/Cl- ratio decreases in the lake. Our calculations indicate major lake-level drops of ∼170 m from lake levels of 320 and 310 m below sea level (mbsl) down to lake levels of ∼490 and ∼480 mbsl, during MIS 5e and the Holocene, respectively. These lake levels are much lower than typical interglacial lake levels of around 400 mbsl. These lake-level drops occurred as a result of major decreases in average fresh water runoff, to ∼40% of the modern value (pre-1964, before major fresh water diversions), reflecting severe droughts during which annual precipitation in Jerusalem was lower than 350 mm/y, compared to ∼600 mm/y today. Nevertheless, even during salt intervals, the changes in halite facies and the occurrence of alternating periods of halite and detritus in the Dead Sea core stratigraphy reflect fluctuations between drier and wetter conditions around our estimated average. The halite intervals include

  17. Long-Term Changes in Cyanobacteria Populations in Lake Kinneret (Sea of Galilee), Israel: An Eco-Physiological Outlook

    PubMed Central

    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

  18. Reply to Discussion: a critique of Possible waterways between the Marmara Sea and the Black Sea in the late Quaternary: evidence from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Geo-Marine Letters, 2011

    NASA Astrophysics Data System (ADS)

    Nazik, Atike; Meriç, Engin; Avşar, Niyazi

    2012-06-01

    In their discussion of our 2011 paper dealing with possible waterways between the Marmara Sea and the Black Sea in the "late" Quaternary, based on data from ostracod and foraminifer assemblages in lakes İznik and Sapanca, Turkey, Yaltırak et al. (Geo-Mar Lett 32:267-274, 2012) essentially reject the idea of any links whatsoever, be they between the Marmara Sea and the lakes İznik and Sapanca, or further to the Black Sea via the valley of the Sakarya River. The evidence they provide in support of their view, however, is essentially circumstantial, in part conjectural, and also inconclusive considering the findings in favour of linkage between the Marmara Sea and the lakes at the very least, while the proposed connection with the Sakarya River valley remains speculative because of the lack of unambiguous data. On the other hand, Yaltırak et al. (Geo-Mar Lett 32:267-274, 2012) do raise valid points of concern which deserve careful future investigation, the most important being the possibility of sample contamination from dumped marine sediment used for construction purposes along some parts of the shore of Lake İznik. We agree that a concerted multidisciplinary effort is required to address the many unresolved issues in connection with the potential waterways proposed by us and others before us.

  19. 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 7α,12α,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.

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

    PubMed

    Xi, Xiaodan; Johnson, Nicholas S; Brant, Cory O; Yun, Sang-Seon; Chambers, Keali L; Jones, A Daniel; Li, Weiming

    2011-08-01

    We developed an assay for measuring 7α,12α,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 [(2)H(5)]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.

  1. 75 FR 21990 - Safety Zone; Extended Debris Removal in the Lake Champlain Bridge Construction Zone (Between...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-27

    ... Lieutenant Junior Grade Laura van der Pol, Coast Guard Sector Northern New England, Waterways Management... compliance, please call or e-mail Lieutenant Junior Grade Laura van der Pol, Coast Guard Sector Northern New..., in the aggregate, or by the private sector of $100,000,000 (adjusted for inflation) or more in...

  2. Deposition and watershed processing of mercury in the Lake Champlain basin

    SciTech Connect

    Scherbatskoy, T.; Rea, A.; Keeler, G.

    1995-12-31

    Daily wet-only precipitation, weekly 24-hour vapor and particulate matter, snowmelt and stream water have been analyzed for total mercury (Hg) in Underhill, VT since December, 1992. Total Hg in precipitation ranged from 1.2-35 ng/L, with maximum concentrations occurring during summer. Vapor phase Hg ranged from 1.2 to 4.2 ng/m, with little annual variability, and particulate phase Hg ranged from 1 to 43 pg/m{sup 3}, with maximum concentrations in winter. Wet-only deposition of total Hg in precipitation totaled 9.26 {mu}g/m{sup 2} in 1993 and 7.66 {mu}g/m{sup 2} in 1994. Total Hg concentrations in a stream in our research watershed were 1-3 ng/L during base flow, and reached 79 ng/L at peak flow during spring snowmelt. Dissolved Hg concentrations were approximately 2 ng/L, even during peak flows, suggesting suspended Hg-containing sediments caused the high total Hg during peak flows. Synoptic sampling of larger streams in the drainage basin also showed significant Hg enrichment during snowmelt. Limited snowpack melt measurements indicated that Hg concentration and dissolved proportion in melt water were dynamic, varying with temperature and melting rate.

  3. 75 FR 22228 - Regulated Navigation Area; Lake Champlain Bridge Construction Zone, NY and VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-28

    ... Construction Zone, NY and VT AGENCY: Coast Guard, DHS. ACTION: Temporary interim rule with request for comments... coordinates: 44 01'59'' N, 073 25'31'' W and 44 02'04'' N, 073 25'28'' W to the north, and 44 01'56'' N, 073 25'08'' W and 44 01'53'' N, 073 25'14'' W to the south. The area will be marked with four white...

  4. Impact of Lake Okeechobee Sea Surface Temperatures on Numerical Predictions of Summertime Convective Systems over South Florida

    NASA Technical Reports Server (NTRS)

    Case, Jonathan L.; Splitt, Michael E.; Fuell, Kevin K.; Santos, Pablo; Lazarus, Steven M.; Jedlovec, Gary J.

    2009-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center, the Florida Institute of Technology, and the NOAA/NWS Weather Forecast Office at Miami, FL (MFL) are collaborating on a project to investigate the impact of using high-resolution, 2-km Moderate Resolution Imaging Spectroradiometer (MODIS) sea surface temperature (SST) composites within the Weather Research and Forecasting (WRF) prediction system. The NWS MFL is currently running WRF in real-time to support daily forecast operations, using the National Centers for Environmental Prediction Nonhydrostatic Mesoscale Model dynamical core within the NWS Science and Training Resource Center's Environmental Modeling System (EMS) software. Twenty-seven hour forecasts are run daily initialized at 0300, 0900, 1500, and 2100 UTC on a domain with 4-km grid spacing covering the southern half of Florida and adjacent waters of the Gulf of Mexico and Atlantic Ocean. The SSTs are initialized with the NCEP Real-Time Global (RTG) analyses at 1/12deg resolution. The project objective is to determine whether more accurate specification of the lower-boundary forcing over water using the MODIS SST composites within the 4-km WRF runs will result in improved sea fluxes and hence, more accurate e\\olutiono f coastal mesoscale circulations and the associated sensible weather elements. SPoRT conducted parallel WRF EMS runs from February to August 2007 identical to the operational runs at NWS MFL except for the use of MODIS SST composites in place of the RTG product as the initial and boundary conditions over water. During the course of this evaluation, an intriguing case was examined from 6 May 2007, in which lake breezes and convection around Lake Okeechobee evolved quite differently when using the high-resolution SPoRT MODIS SST composites versus the lower-resolution RTG SSTs. This paper will analyze the differences in the 6 May simulations, as well as examine other cases from the summer 2007 in which the WRF

  5. The high Sea Level History of Beringia and its correspondence with Super Interglacials and Warm Pliocene at Lake El'gygytgyn, NE Russia - Links to Antarctica

    NASA Astrophysics Data System (ADS)

    Brigham-Grette, J.; Roychowdhury, R.; Deconto, R. M.; Melles, M.; Minyuk, P.

    2014-12-01

    The coastal regions of central Beringia contain a well-studied sequence of marine shorelines consisting of barrier beach sequences and broad coastal plans of superposed marine sediment. These sequences include shorelines associated with 2 Pliocene high sea stands, and lower shorelines dated to MIS 31, MIS 11, and MIS 5e. All of these shorelines correspond with super interglacials identified in the Lake El'gygytgyn paleoclimate record (Lake E), NE Arctic Russia. However, not all super interglacials correspond with a recorded high sea level event in the western Arctic. We argue that most of the high sea stands in central and northern Beringia, especially the NW coast of Alaska, likely require at least the partial demise of Greenland, or WAIS, or EAIS, or some combination of the three. How do we evaluate what melted and why? MIS 31 was a remarkably warm interval found in the ANDRILL and other marine records around Antarctica. Half a prerecession cycle after this warmth in Antarctica, we see a super interglacial MIS 31 in Lake E. Because of unconformities in the ANDRILL record, MIS 31 still provides the best match with Lake E, but we postulate that other intervals marked by the deposition of diatomaceous ooze in the ANDRILL record may also correspond to many of our interglacials. The challenge has been to determine orbital phasing relationships between warmth in the south and warmth in the north. Here we explore this relationship starting with the striking observation that most super interglacials correspond with extremely low eccentricity, but lagged by ~53kyrs. We explore how orbital conditions may have preconditioned the polar regions to produce a large response during some interglacials; linking changes in polar ice sheet size to sea level and interglacial extremes recorded at Lake E.

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

    USGS Publications Warehouse

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

    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 lam-prey 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.

  7. Comparative analysis of ammonia monooxygenase (amoA) genes in the water column and sediment-water interface of two lakes and the Baltic Sea.

    PubMed

    Kim, Ok-Sun; Junier, Pilar; Imhoff, Johannes F; Witzel, Karl-Paul

    2008-11-01

    The functional gene amoA was used to compare the diversity of ammonia-oxidizing bacteria (AOB) in the water column and sediment-water interface of the two freshwater lakes Plusssee and Schöhsee and the Baltic Sea. Nested amplifications were used to increase the sensitivity of amoA detection, and to amplify a 789-bp fragment from which clone libraries were prepared. The larger part of the sequences was only distantly related to any of the cultured AOB and is considered to represent new clusters of AOB within the Nitrosomonas/Nitrosospira group. Almost all sequences from the water column of the Baltic Sea and from 1-m depth of Schöhsee were related to different Nitrosospira clusters 0 and 2, respectively. The majority of sequences from Plusssee and Schöhsee were associated with sequences from Chesapeake Bay, from a previous study of Plusssee and from rice roots in Nitrosospira-like cluster A, which lacks sequences from Baltic Sea. Two groups of sequences from Baltic Sea sediment were related to clonal sequences from other brackish/marine habitats in the purely environmental Nitrosospira-like cluster B and the Nitrosomonas-like cluster. This confirms previous results from 16S rRNA gene libraries that indicated the existence of hitherto uncultivated AOB in lake and Baltic Sea samples, and showed a differential distribution of AOB along the water column and sediment of these environments.

  8. Analysis of Lake Baikal's phytoplankton and fluvial input dynamics using SeaWiFS satellite data within the Scope of the Paleoclimate Project CONTINENT

    NASA Astrophysics Data System (ADS)

    Heim, B.; Oberhaensli, H.; Kaufmann, H.

    2003-04-01

    Multispectral ocean colour satellite data provide a new tool for spatial and temporal limnological data overview. The Ulaan Baatar (Mongolia) HRPT (high resolution picture transmission) station provides the paleoclimate EC-Project CONTINENT "High Resolution CONTINENTal Paleoclimate Record in Lake Baikal (Siberia, Russia)" with daily SeaWiFS data covering the area of south-eastern Siberia. After a SeaWiFS data processing chain with radiometric and atmospheric correction, we use the water leaving reflectances to gain information on phytoplankton and suspended sediment whose dynamics are a response to the present climate forcing. During the CONTINENT Summer cruises in 2001 and 2002, we were able to verify the spectral analysis of SeaWiFS satellite data with a high quality calibration/validation ground truth data set (field spectrometer and fluorometer measurement activities simultaneously to water sampling activities for pigment and suspended matter SPM and DOC analysis and algae counting). The fluviatil input into Lake Baikal is visible in the SeaWiFS data due to its higher loads of suspended matter, further particularly due to the presence of coloured dissolved organic matter (cDOM). These coloured fraction of DOM (mainly humic acids) originate from the bog areas and swampy basins within the Lake Baikal watershed. The so called yellow substances react optically with a strong absorption in the blue spectral bands of SeaWiFS and are therefore ideal tracers for the river input even over long distances from the river inflow. The phytoplankton main pigment chlorophyll-a is made visible by its absorption band in the blue which results in a green reflectance peak. Additional pigment groups (carotinoids, phycobilins) differentiate the spectral shape of the water leaving reflectance depending on the respective main phytoplankton composition. On satellite images obtained in late Summer, we can differentiate between diatom and cyanobacteria-picoplankton dominated surface water

  9. Depth profiles of spectral and hydrological characteristics of water and their relation to abundances of green sulfur bacteria in the stratified lakes of the White Sea

    NASA Astrophysics Data System (ADS)

    Kharcheva, Anastasia V.; Krasnova, Elena D.; Gorlenko, Vladimir M.; Lunina, Olga N.; Savvichev, Alexander S.; Voronov, Dmitry A.; Zhiltsova, Anna A.; Patsaeva, Svetlana V.

    2016-04-01

    We analyze the results received from two expeditions performed in August-September 2013, August-September 2014 and February 2015 in the Kandalaksha Bay of the White Sea. Depth profiles of hydrological characteristics and optical properties of water were recorded for five marine lakes being on different stages of isolation from the White Sea. Those relic lakes demonstrate a tendency to meromixis and are characterized by apparent stratification of the water bodies from the brackish top layer to the bottom salt water. Maximal concentrations of anoxygenic phototrophs (green sulfur bacteria) were found at depths close to the redox interface in all the studied lakes. To discriminate differently pigmented groups of microorganisms the fluorescence emission spectra of bacteriochlorophylls from the living cells were used. We puzzle out the data on light spectrum propagation through the water body in each lake using optical properties of water (attenuation spectra) in the UV, visible and NIR ranges, as well as direct measurements of the total irradiances at various depths. The changes in optical characteristics of water in the stratified reservoirs due to cromophoric dissolved organic matter (CDOM) and microbial pigments affect the light intensity and its spectral distribution at each water layer thus influencing the living conditions for differently pigmented phototrophic microorganisms and determining the composition of microbial community.

  10. Parameterization of the light absorption properties of chromophoric dissolved organic matter in the Baltic Sea and Pomeranian lakes

    NASA Astrophysics Data System (ADS)

    Meler, Justyna; Kowalczuk, Piotr; Ostrowska, Mirosława; Ficek, Dariusz; Zabłocka, Monika; Zdun, Agnieszka

    2016-08-01

    This study presents three alternative models for estimating the absorption properties of chromophoric dissolved organic matter aCDOM(λ). For this analysis we used a database containing 556 absorption spectra measured in 2006-2009 in different regions of the Baltic Sea (open and coastal waters, the Gulf of Gdańsk and the Pomeranian Bay), at river mouths, in the Szczecin Lagoon and also in three lakes in Pomerania (Poland) - Obłęskie, Łebsko and Chotkowskie. The variability range of the chromophoric dissolved organic matter (CDOM) absorption coefficient at 400 nm, aCDOM(400), lay within 0.15-8.85 m-1. The variability in aCDOM(λ) was parameterized with respect to the variability over 3 orders of magnitude in the chlorophyll a concentration Chl a (0.7-119 mg m-3). The chlorophyll a concentration and aCDOM(400) were correlated, and a statistically significant, nonlinear empirical relationship between these parameters was derived (R2 = 0.83). On the basis of the covariance between these parameters, we derived two empirical mathematical models that enabled us to design the CDOM absorption coefficient dynamics in natural waters and reconstruct the complete CDOM absorption spectrum in the UV and visible spectral domains. The input variable in the first model was the chlorophyll a concentration, and in the second one it was aCDOM(400). Both models were fitted to a power function, and a second-order polynomial function was used as the exponent. Regression coefficients for these formulas were determined for wavelengths from 240 to 700 nm at 5 nm intervals. Both approximations reflected the real shape of the absorption spectra with a low level of uncertainty. Comparison of these approximations with other models of light absorption by CDOM demonstrated that our parameterizations were superior (bias from -1.45 to 62 %, RSME from 22 to 220 %) for estimating CDOM absorption in the optically complex waters of the Baltic Sea and Pomeranian lakes.

  11. Evaluation of strategies for the release of male sea lampreys (Petromyzon marinus) in Lake Superior for a proposed sterile-male-release program

    USGS Publications Warehouse

    Kaye, C.A.; Heinrich, J.W.; Genovese, J.H.; Hanson, L.H.; McDonald, R.B.; Slade, J.W.; Swink, W.D.

    2003-01-01

    Successful implementation of a sea lamprey (Petromyzon marinus) control technique that uses sterilized males to reduce reproduction presently depends on the importation of large numbers of males outside of the target population. Strategies were examined for releasing male sea lampreys from Lakes Michigan and Huron into the Lake Superior spawning population and the ability of these introduced males to compete with resident males and spawn with resident females. During 1987, 553 (9%) of 6,324 imported fertile males released at 12 shoreline and one offshore site in Lake Superior were recaptured. Most remained within 20 km of the release site and entered the first stream encountered. During 1988, 393 (18%) of 2,208 imported fertile males released directly into three spawning rivers were recaptured. In both cases, animals released early during the spawning run were more likely to be recaptured than those released later. Introduced males successfully competed with resident males and spawned with resident females. Demonstrating that male sea lampreys could reproduce successfully when relocated supported subsequent large-scale field trials of the sterile-male-release technique.

  12. Examining Dual Frequency X- and Ku-band Backscatter of Snow on Lake Ice and First-Year Sea Ice in the Sub-Arctic Hudson Bay Lowlands

    NASA Astrophysics Data System (ADS)

    Gunn, G. E.; Duguay, C. R.; Howell, S.; Kelly, R. E.; Silis, A.

    2011-12-01

    Fully polarimetric dual frequency ground-based scatterometer observations were collected at X- and Ku-band (9.6 and 17.2 GHz, respectively) near Churchill, Manitoba, Canada in the winter of 2010-11 as part of the Canadian Snow and Ice Experiment (CASIX). Backscatter measurements were collected for five landcover types: lake ice, sea ice, dry tundra, open forest and wetland tundra (sedge fen); the combination of which comprises a unique dataset of dual-frequency backscatter signatures. Correlative data collected, including snow and ice properties, are utilized to characterize active microwave interactions and contribute to the development of snow/ice retrieval algorithms. This study presents backscatter signatures for lake and sea ice obtained during winter 2010-11. The seasonal backscatter evolution is compared to changes in snow and ice properties, including depth, density, snow water equivalent (SWE), ice thickness, ice type, and bubble concentration within the ice. Results over lake ice suggest that increases in backscatter at both X- and Ku-band frequencies correspond to increases in SWE, but are confounded by changes in the sub-nivian ice composition. Surface ice types (snow ice, rafted ice), high bubble concentrations at the ice/water interface and pressure/deformation cracks in the ice serve to confound backscatter at several monitoring sites. Over sea ice, preliminary results indicate that increased salinity levels near the ice/snow interface is the predominate factor influencing backscatter signatures. Physical phenomena encountered at sea ice sites are further explored to assess potential influences on scattering signatures. Preliminary findings presented here document the first ground-based dual frequency X- and Ku-band backscatter signatures collected over first year sea ice, and contribute to the scientific objectives of the proposed Cold Regions Hydrology High-resolution Observatory (CoReH2O), a candidate Earth Explorer mission of the European Space

  13. Multilevel Empirical Bayes Modeling for Improved Estimation of Toxicant Formulations to Suppress Parasitic Sea Lamprey in the Upper Great Lakes

    USGS Publications Warehouse

    Hatfield, L.A.; Gutreuter, S.; Boogaard, M.A.; Carlin, B.P.

    2011-01-01

    Estimation of extreme quantal-response statistics, such as the concentration required to kill 99.9% of test subjects (LC99.9), remains a challenge in the presence of multiple covariates and complex study designs. Accurate and precise estimates of the LC99.9 for mixtures of toxicants are critical to ongoing control of a parasitic invasive species, the sea lamprey, in the Laurentian Great Lakes of North America. The toxicity of those chemicals is affected by local and temporal variations in water chemistry, which must be incorporated into the modeling. We develop multilevel empirical Bayes models for data from multiple laboratory studies. Our approach yields more accurate and precise estimation of the LC99.9 compared to alternative models considered. This study demonstrates that properly incorporating hierarchical structure in laboratory data yields better estimates of LC99.9 stream treatment values that are critical to larvae control in the field. In addition, out-of-sample prediction of the results of in situ tests reveals the presence of a latent seasonal effect not manifest in the laboratory studies, suggesting avenues for future study and illustrating the importance of dual consideration of both experimental and observational data. ?? 2011, The International Biometric Society.

  14. 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.

  15. Multilevel empirical bayes modeling for improved estimation of toxicant formulations to suppress parasitic sea lamprey in the upper great lakes.

    PubMed

    Hatfield, Laura A; Gutreuter, Steve; Boogaard, Michael A; Carlin, Bradley P

    2011-09-01

    Estimation of extreme quantal-response statistics, such as the concentration required to kill 99.9% of test subjects (LC99.9), remains a challenge in the presence of multiple covariates and complex study designs. Accurate and precise estimates of the LC99.9 for mixtures of toxicants are critical to ongoing control of a parasitic invasive species, the sea lamprey, in the Laurentian Great Lakes of North America. The toxicity of those chemicals is affected by local and temporal variations in water chemistry, which must be incorporated into the modeling. We develop multilevel empirical Bayes models for data from multiple laboratory studies. Our approach yields more accurate and precise estimation of the LC99.9 compared to alternative models considered. This study demonstrates that properly incorporating hierarchical structure in laboratory data yields better estimates of LC99.9 stream treatment values that are critical to larvae control in the field. In addition, out-of-sample prediction of the results of in situ tests reveals the presence of a latent seasonal effect not manifest in the laboratory studies, suggesting avenues for future study and illustrating the importance of dual consideration of both experimental and observational data.

  16. Predicting minimum habitat characteristics for the Indiana bat in the Champlain Valley

    USGS Publications Warehouse

    Watrous, K.S.; Donovan, T.M.; Mickey, R.M.; Darling, S.R.; Hicks, A.C.; Von Oettingen, S. L.

    2006-01-01

    Predicting potential habitat across a landscape for rare species is extremely challenging. However, partitioned Mahalanobis D2 methods avoid pitfalls commonly encountered when surveying rare species by using data collected only at known species locations. Minimum habitat requirements are then determined by examining a principal components analysis to find consistent habitat characteristics across known locations. We used partitioned D 2 methods to examine minimum habitat requirements of Indiana bats (Myotis sodalis) in the Champlain Valley of Vermont and New York, USA, across 7 spatial scales and map potential habitat for the species throughout the same area. We radiotracked 24 female Indiana bats to their roost trees and across their nighttime foraging areas to collect habitat characteristics at 7 spatial scales: 1) roost trees, 2) 0.1-ha circular plots surrounding the roost trees, 3) home ranges, and 4-7) 0.5-km, 1-km, 2-km, and 3-km buffers surrounding the roost tree. Roost trees (n = 50) typically were tall, dead, large-diameter trees with exfoliating bark, located at low elevations and close to water. Trees surrounding roosts typically were smaller in diameter and shorter in height, but they had greater soundness than the roost trees. We documented 14 home ranges in areas of diverse, patchy land cover types that were close to water with east-facing aspects. Across all landscape extents, area of forest within roost-tree buffers and the aspect across those buffers were the most consistent features. Predictive maps indicated that suitable habitat ranged from 4.7-8.1% of the area examined within the Champlain Valley. These habitat models further understanding of Indiana bat summer habitat by indicating minimum habitat characteristics at multiple scales and can be used to aid management decisions by highlighting potential habitat. Nonetheless, information on juvenile production and recruitment is lacking; therefore, assessments of Indiana bat habitat quality in the

  17. Low-head sea lamprey barrier effects on stream habitat and fish communities in the Great Lakes basin

    USGS Publications Warehouse

    Dodd, H.R.; Hayes, D.B.; Baylis, J.R.; Carl, L.M.; Goldstein, J.D.; McLaughlin, R.L.; Noakes, D.L.G.; Porto, L.M.; Jones, M.L.

    2003-01-01

    Low-head barriers are used to block adult sea lamprey (Petromyzon marinus) from upstream spawning habitat. However, these barriers may impact stream fish communities through restriction of fish movement and habitat alteration. During the summer of 1996, the fish community and habitat conditions in twenty-four stream pairs were sampled across the Great Lakes basin. Seven of these stream pairs were re-sampled in 1997. Each pair consisted of a barrier stream with a low-head barrier and a reference stream without a low-head barrier. On average, barrier streams were significantly deeper (df = 179, P = 0.0018) and wider (df = 179, P = 0.0236) than reference streams, but temperature and substrate were similar (df = 183, P = 0.9027; df = 179, P = 0.999). Barrier streams contained approximately four more fish species on average than reference streams. However, streams with low-head barriers showed a greater upstream decline in species richness compared to reference streams with a net loss of 2.4 species. Barrier streams also showed a peak in richness directly downstream of the barriers, indicating that these barriers block fish movement upstream. Using S??renson's similarity index (based on presence/absence), a comparison of fish community assemblages above and below low-head barriers was not significantly different than upstream and downstream sites on reference streams (n = 96, P > 0.05), implying they have relatively little effect on overall fish assemblage composition. Differences in the frequency of occurrence and abundance between barrier and reference streams was apparent for some species, suggesting their sensitivity to barriers.

  18. Halorhabdus tiamatea: proteogenomics and glycosidase activity measurements identify the first cultivated euryarchaeon from a deep-sea anoxic brine lake as potential polysaccharide degrader.

    PubMed

    Werner, Johannes; Ferrer, Manuel; Michel, Gurvan; Mann, Alexander J; Huang, Sixing; Juarez, Silvia; Ciordia, Sergio; Albar, Juan P; Alcaide, María; La Cono, Violetta; Yakimov, Michail M; Antunes, André; Taborda, Marco; da Costa, Milton S; Hai, Tran; Glöckner, Frank Oliver; Golyshina, Olga V; Golyshin, Peter N; Teeling, Hanno

    2014-08-01

    Euryarchaea from the genus Halorhabdus have been found in hypersaline habitats worldwide, yet are represented by only two isolates: Halorhabdus utahensis AX-2(T) from the shallow Great Salt Lake of Utah, and Halorhabdus tiamatea SARL4B(T) from the Shaban deep-sea hypersaline anoxic lake (DHAL) in the Red Sea. We sequenced the H. tiamatea genome to elucidate its niche adaptations. Among sequenced archaea, H. tiamatea features the highest number of glycoside hydrolases, the majority of which were expressed in proteome experiments. Annotations and glycosidase activity measurements suggested an adaptation towards recalcitrant algal and plant-derived hemicelluloses. Glycosidase activities were higher at 2% than at 0% or 5% oxygen, supporting a preference for low-oxygen conditions. Likewise, proteomics indicated quinone-mediated electron transport at 2% oxygen, but a notable stress response at 5% oxygen. Halorhabdus tiamatea furthermore encodes proteins characteristic for thermophiles and light-dependent enzymes (e.g. bacteriorhodopsin), suggesting that H. tiamatea evolution was mostly not governed by a cold, dark, anoxic deep-sea habitat. Using enrichment and metagenomics, we could demonstrate presence of similar glycoside hydrolase-rich Halorhabdus members in the Mediterranean DHAL Medee, which supports that Halorhabdus species can occupy a distinct niche as polysaccharide degraders in hypersaline environments.

  19. Halorhabdus tiamatea: proteogenomics and glycosidase activity measurements identify the first cultivated euryarchaeon from a deep-sea anoxic brine lake as potential polysaccharide degrader

    PubMed Central

    Werner, Johannes; Ferrer, Manuel; Michel, Gurvan; Mann, Alexander J; Huang, Sixing; Juarez, Silvia; Ciordia, Sergio; Albar, Juan P; Alcaide, María; La Cono, Violetta; Yakimov, Michail M; Antunes, André; Taborda, Marco; da Costa, Milton S; Hai, Tran; Glöckner, Frank Oliver; Golyshina, Olga V; Golyshin, Peter N; Teeling, Hanno; The MAMBA Consortium

    2014-01-01

    Euryarchaea from the genus Halorhabdus have been found in hypersaline habitats worldwide, yet are represented by only two isolates: Halorhabdus utahensis AX-2T from the shallow Great Salt Lake of Utah, and Halorhabdus tiamatea SARL4BT from the Shaban deep-sea hypersaline anoxic lake (DHAL) in the Red Sea. We sequenced the H. tiamatea genome to elucidate its niche adaptations. Among sequenced archaea, H. tiamatea features the highest number of glycoside hydrolases, the majority of which were expressed in proteome experiments. Annotations and glycosidase activity measurements suggested an adaptation towards recalcitrant algal and plant-derived hemicelluloses. Glycosidase activities were higher at 2% than at 0% or 5% oxygen, supporting a preference for low-oxygen conditions. Likewise, proteomics indicated quinone-mediated electron transport at 2% oxygen, but a notable stress response at 5% oxygen. Halorhabdus tiamatea furthermore encodes proteins characteristic for thermophiles and light-dependent enzymes (e.g. bacteriorhodopsin), suggesting that H. tiamatea evolution was mostly not governed by a cold, dark, anoxic deep-sea habitat. Using enrichment and metagenomics, we could demonstrate presence of similar glycoside hydrolase-rich Halorhabdus members in the Mediterranean DHAL Medee, which supports that Halorhabdus species can occupy a distinct niche as polysaccharide degraders in hypersaline environments. PMID:24428220

  20. Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This series of MODIS images shows the dwindling Aral Sea. Once one of the world's largest freshwater lakes, the Aral Sea has decreased by as much as 60% over the past few decades due to diversion of the water to grow cotton and rice. These diversion have dropped the lake levels, increased salinity, and nearly decimated the fishing industry. The previous extent of the lake is clearly visible as a whitish perimeter in these image from April 16, May 18, and June 3, 2002. s. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  1. In-Flight Validation of Mid and Thermal Infrared Remotely Sensed Data Using the Lake Tahoe and Salton Sea Automated Validation Sites

    NASA Technical Reports Server (NTRS)

    Hook, Simon J.

    2008-01-01

    The presentation includes an introduction, Lake Tahoe site layout and measurements, Salton Sea site layout and measurements, field instrument calibration and cross-calculations, data reduction methodology and error budgets, and example results for MODIS. Summary and conclusions are: 1) Lake Tahoe CA/NV automated validation site was established in 1999 to assess radiometric accuracy of satellite and airborne mid and thermal infrared data and products. Water surface temperatures range from 4-25C.2) Salton Sea CA automated validation site was established in 2008 to broaden range of available water surface temperatures and atmospheric water vapor test cases. Water surface temperatures range from 15-35C. 3) Sites provide all information necessary for validation every 2 mins (bulk temperature, skin temperature, air temperature, wind speed, wind direction, net radiation, relative humidity). 4) Sites have been used to validate mid and thermal infrared data and products from: ASTER, AATSR, ATSR2, MODIS-Terra, MODIS-Aqua, Landsat 5, Landsat 7, MTI, TES, MASTER, MAS. 5) Approximately 10 years of data available to help validate AVHRR.

  2. Oxygen-isotope variations in post-glacial Lake Ontario

    NASA Astrophysics Data System (ADS)

    Hladyniuk, Ryan; Longstaffe, Fred J.

    2016-02-01

    The role of glacial meltwater input to the Atlantic Ocean in triggering the Younger Dryas (YD) cooling event has been the subject of controversy in recent literature. Lake Ontario is ideally situated to test for possible meltwater passage from upstream glacial lakes and the Laurentide Ice Sheet (LIS) to the Atlantic Ocean via the lower Great Lakes. Here, we use the oxygen-isotope compositions of ostracode valves and clam shells from three Lake Ontario sediment cores to identify glacial meltwater contributions to ancient Lake Ontario since the retreat of the LIS (∼16,500 cal [13,300 14C] BP). Differences in mineralogy and sediment grain size are also used to identify changes in the hydrologic regime. The average lakewater δ18O of -17.5‰ (determined from ostracode compositions) indicates a significant contribution from glacial meltwater. Upon LIS retreat from the St. Lawrence lowlands, ancient Lake Ontario (glacial Lake Iroquois) lakewater δ18O increased to -12‰ largely because of the loss of low-18O glacial meltwater input. A subsequent decrease in lakewater δ18O (from -12 to -14‰), accompanied by a median sediment grain size increase to 9 μm, indicates that post-glacial Lake Ontario received a final pulse of meltwater (∼13,000-12,500 cal [11,100-10,500 14C] BP) before the onset of hydrologic closure. This meltwater pulse, which is also recorded in a previously reported brief freshening of the neighbouring Champlain Valley (Cronin et al., 2012), may have contributed to a weakening of thermohaline circulation in the Atlantic Ocean. After 12,900 cal [11,020 14C] BP, the meltwater presence in the Ontario basin continued to inhibit entry of Champlain seawater into early Lake Ontario. Opening of the North Bay outlet diverted upper Great Lakes water from the lower Great Lakes causing a period (12,300-8300 cal [10,400-7500 14C] BP) of hydrologic closure in Lake Ontario (Anderson and Lewis, 2012). This change is demarcated by a shift to higher δ18Olakewater

  3. 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

  4. Lithology and late postglacial stratigraphy of bottom sediments in isolated basins of the White Sea coast exemplified by a small lake in the Chupa settlement area (Northern Karelia)

    NASA Astrophysics Data System (ADS)

    Korsakova, O. P.; Kolka, V. V.; Tolstobrova, A. N.; Lavrova, N. B.; Tolstobrov, D. S.; Shelekhova, T. S.

    2016-05-01

    The complex lithological, geochemical, geochronological, and micropaleontological (diatoms, spores, pollen) investigations of stratified bottom sediments that constitute facies-variable sedimentary sequences in a small isolated lake located near the upper limit of the sea on the White Sea coast made it possible to define lithostratigraphic units (LSU) forming the complete sedimentary succession in deep parts of isolated basins. It is shown that stratigraphy of heterogeneous sequences is determined by two regional transgressive-regressive cycles in relative sea level fluctuations: alternating late Glacial and Holocene transgressions and regressions. The lower part of a clastogenic clayey-sandy-silty sequence successively composed of freshwater (LSU 1) and brackish-water (LSU 2) sediments of the ice-marginal basins and marine postglacial facies (LSU 3) was formed during the late Glacial glacioeustatic marine transgression. Its upper part formed in different isolated basins at different stages of the Holocene is represented depending on its altimetric position on the coastal slope by costal marine sediments (LSU 4) and facies of the partly isolated inlet (LSU 5). The organogenic sapropelic sequence, which overlies sediments of the marine basin and partly isolated bay, corresponds to lithostratigraphic units represented by Holocene sediments accumulated in the meromictic lake (LSU 6), onshore freshwater basin (LSU 7), and freshwater basin with elevated water mineralization (LSU 8) deposited during maximum development of Holocene transgression and lacustrine sediments (LSU 9) formed in coastal environments during terminal phases of the Holocene. The defined lithostratigraphic units differ from each other in lithological, micropaleontological, and geochemical features reflected in structural and textural properties of their sediments, their composition, inclusions, and composition of paleophytocoenoses and diatom assemblages.

  5. Threshold of wave generation on Titan’s lakes and seas: Effect of viscosity and implications for Cassini observations

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Newman, Claire; Lunine, Jonathan I.

    2010-06-01

    Motivated by radar and near-infrared data indicating that Titan's polar lakes are extremely smooth, we consider the conditions under which a lake surface will be ruffled by wind to form capillary waves. We evaluate laboratory data on wind generation and derive, without scaling for surface tension effects, a threshold for pure methane/ethane of ˜0.5-1 m/s. However, we compute the physical properties of predicted Titan lake compositions using the National Institute for Standards Technology (NIST) code and note that dissolved amounts of C3 and C4 compounds are likely to make Titan lakes much more viscous than pure ethane or methane, even without allowing for suspended particulates which would increase the viscosity further. Wind tunnel experiments show a strong dependence of capillary wave growth on liquid viscosity, and this effect may explain the apparent absence so far of waves, contrary to prior expectations that generation of gravity waves by wind should be easy on Titan. On the other hand, we note that winds over Titan lakes predicted with the TitanWRF Global Circulation Model indicate radar observations so far have in any case been when winds have been low (˜0.5-0.7 m/s), possibly below the wave generation threshold, while peak winds during summer may reach 1-2 m/s. Thus observations of Titan's northern lakes during the coming years by the Cassini Solstice mission offer the highest probability of observing wind-roughening of lake surfaces, while observations of Ontario Lacus in the south will likely continue to show it to be flat and smooth.

  6. 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.

  7. [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 μg 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 μg S L(-1) day(-1) and 2.9 μL CH4 L(-1) day(-1)). The isotopic composition of dissolved methane from the near-bottom water layer (δ13C (CH4) = -87.76 per thousand) was significantly lighter than in the upper horizons (δ13C (CH4) = -77.95 per thousand). The most isotopically heavy methane (δ13C (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

  8. Rebel Privateers--The Winners of American Independence

    DTIC Science & Technology

    1990-06-01

    Arnold’s stalling for time with his Lake Champlain flotilla which saved the rebellion and brought France into the war, and the victory at Yorktown, which was...sea the height of folly, .... the maddest idea in the world", according to Samuel Chase of Maryland. (5) Many agreed. Later on, when it became clear...place. An American "fleet" under General Benedict Arnold g)bllanged the British on Lake Champlain . Known as the Battle of Valcour Island, the

  9. A Three-Component Microbial Consortium from Deep-Sea Salt-Saturated Anoxic Lake Thetis Links Anaerobic Glycine Betaine Degradation with Methanogenesis

    PubMed Central

    La Cono, Violetta; Arcadi, Erika; La Spada, Gina; Barreca, Davide; Laganà, Giuseppina; Bellocco, Ersilia; Catalfamo, Maurizio; Smedile, Francesco; Messina, Enzo; Giuliano, Laura; Yakimov, Michail M.

    2015-01-01

    Microbial communities inhabiting the deep-sea salt-saturated anoxic lakes of the Eastern Mediterranean operate under harsh physical-chemical conditions that are incompatible with the lifestyle of common marine microorganisms. Here, we investigated a stable three-component microbial consortium obtained from the brine of the recently discovered deep-sea salt-saturated Lake Thetis. The trophic network of this consortium, established at salinities up to 240, relies on fermentative decomposition of common osmoprotectant glycine betaine (GB). Similarly to known extreme halophilic anaerobic GB-degrading enrichments, the initial step of GB degradation starts with its reductive cleavage to trimethylamine and acetate, carried out by the fermenting member of the Thetis enrichment, Halobacteroides lacunaris TB21. In contrast to acetate, which cannot be easily oxidized in salt-saturated anoxic environments, trimethylamine represents an advantageous C1-substrate for methylotrophic methanogenic member of the Thetis enrichment, Methanohalophilus sp. TA21. This second member of the consortium likely produces hydrogen via methylotrophic modification of reductive acetyl-CoA pathway because the initial anaerobic GB cleavage reaction requires the consumption of reducing equivalents. Ecophysiological role of the third member of the Thetis consortium, Halanaerobium sp. TB24, which lacks the capability of either GB or trimethylamine degradation, remains yet to be elucidated. As it is true for cultivated members of family Halanaerobiaceae, the isolate TB24 can obtain energy primarily by fermenting simple sugars and producing hydrogen as one of the end products. Hence, by consuming of TB21 and TA21 metabolites, Halanaerobium sp. TB24 can be an additional provider of reducing equivalents required for reductive degradation of GB. Description of the Thetis GB-degrading consortium indicated that anaerobic degradation of osmoregulatory molecules may play important role in the overall turnover of

  10. A Three-Component Microbial Consortium from Deep-Sea Salt-Saturated Anoxic Lake Thetis Links Anaerobic Glycine Betaine Degradation with Methanogenesis.

    PubMed

    Cono, Violetta La; Arcadi, Erika; Spada, Gina La; Barreca, Davide; Laganà, Giuseppina; Bellocco, Ersilia; Catalfamo, Maurizio; Smedile, Francesco; Messina, Enzo; Giuliano, Laura; Yakimov, Michail M

    2015-09-09

    Microbial communities inhabiting the deep-sea salt-saturated anoxic lakes of the Eastern Mediterranean operate under harsh physical-chemical conditions that are incompatible with the lifestyle of common marine microorganisms. Here, we investigated a stable three-component microbial consortium obtained from the brine of the recently discovered deep-sea salt-saturated Lake Thetis. The trophic network of this consortium, established at salinities up to 240, relies on fermentative decomposition of common osmoprotectant glycine betaine (GB). Similarly to known extreme halophilic anaerobic GB-degrading enrichments, the initial step of GB degradation starts with its reductive cleavage to trimethylamine and acetate, carried out by the fermenting member of the Thetis enrichment, Halobacteroides lacunaris TB21. In contrast to acetate, which cannot be easily oxidized in salt-saturated anoxic environments, trimethylamine represents an advantageous C₁-substrate for methylotrophic methanogenic member of the Thetis enrichment, Methanohalophilus sp. TA21. This second member of the consortium likely produces hydrogen via methylotrophic modification of reductive acetyl-CoA pathway because the initial anaerobic GB cleavage reaction requires the consumption of reducing equivalents. Ecophysiological role of the third member of the Thetis consortium, Halanaerobium sp. TB24, which lacks the capability of either GB or trimethylamine degradation, remains yet to be elucidated. As it is true for cultivated members of family Halanaerobiaceae, the isolate TB24 can obtain energy primarily by fermenting simple sugars and producing hydrogen as one of the end products. Hence, by consuming of TB21 and TA21 metabolites, Halanaerobium sp. TB24 can be an additional provider of reducing equivalents required for reductive degradation of GB. Description of the Thetis GB-degrading consortium indicated that anaerobic degradation of osmoregulatory molecules may play important role in the overall turnover

  11. Lake trout rehabilitation in Lake Ontario

    USGS Publications Warehouse

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

    1995-01-01

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

  12. Lake trout rehabilitation in Lake Huron

    USGS Publications Warehouse

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

    1995-01-01

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

  13. 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...

  14. 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

  15. Reproductive isolation, evolutionary distinctiveness and setting conservation priorities: The case of European lake whitefish and the endangered North Sea houting (Coregonus spp.)

    PubMed Central

    2008-01-01

    Background Adaptive radiation within fishes of the Coregonus lavaretus complex has created numerous morphs, posing significant challenges for taxonomy and conservation priorities. The highly endangered North Sea houting (C. oxyrhynchus; abbreviated NSH) has been considered a separate species from European lake whitefish (C. lavaretus; abbreviated ELW) due to morphological divergence and adaptation to oceanic salinities. However, its evolutionary and taxonomic status is controversial. We analysed microsatellite DNA polymorphism in nine populations from the Jutland Peninsula and the Baltic Sea, representing NSH (three populations, two of which are reintroduced) and ELW (six populations). The objectives were to: 1) analyse postglacial recolonization of whitefish in the region; 2) assess the evolutionary distinctiveness of NSH, and 3) apply several approaches for defining conservation units towards setting conservation priorities for NSH. Results Bayesian cluster analyses of genetic differentiation identified four major groups, corresponding to NSH and three groups of ELW (Western Jutland, Central Jutland, Baltic Sea). Estimates of historical migration rates indicated recolonization in a north-eastern direction, suggesting that all except the Baltic Sea population predominantly represent postglacial recolonization via the ancient Elbe River. Contemporary gene flow has not occurred between NSH and ELW, with a divergence time within the last 4,000 years suggested from coalescence methods. NSH showed interbreeding with ELW when brought into contact by stocking. Thus, reproductive isolation of NSH was not absolute, although possible interbreeding beyond the F1 level could not be resolved. Conclusion Fishes of the C. lavaretus complex in the Jutland Peninsula originate from the same recolonization event. NSH has evolved recently and its species status may be questioned due to incomplete reproductive isolation from ELW, but it was shown to merit consideration as an

  16. Experimental control of sea lampreys with electricity on the south shore of Lake Superior, 1953-60

    USGS Publications Warehouse

    McLain, Alberton L.; Smith, Bernard R.; Moore, Harry H.

    1965-01-01

    Electric devices of the type and design used are capable of blocking entire runs of adult sea lampreys. An accurate appraisal of the effectiveness of the barrier system is impossible, however. Most of the barriers were not operated long enough to reduce the contribution of parasites from the streams. Furthermore, a complete system of efficient electric barriers was never realized. The greatest weakness of this method of control lies in maintenance of the units in continuous, uninterrupted operation through consecutive migratory seasons.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  18. Microbial community of a hydrothermal mud vent underneath the deep-sea anoxic brine lake Urania (eastern Mediterranean).

    PubMed

    Yakimov, Michail M; Giuliano, Laura; Cappello, Simone; Denaro, Renata; Golyshin, Peter N

    2007-04-01

    The composition of a metabolically active prokaryotic community thriving in hydrothermal mud fluids of the deep-sea hypersaline anoxic Western Urania Basin was characterized using rRNA-based phylogenetic analysis of a clone library. The physiologically active prokaryotic assemblage in this extreme environment showed a great genetic diversity. Most members of the microbial community appeared to be affiliated to yet uncultured organisms from similar ecosystems, i.e., deep-sea hypersaline basins and hydrothermal vents. The bacterial clone library was dominated by phylotypes affiliated with the epsilon-Proteobacteria subdivision recognized as an ecologically significant group of bacteria inhabiting deep-sea hydrothermal environments. Almost 18% of all bacterial clones were related to delta-Proteobacteria, suggesting that sulfate reduction is one of the dominant metabolic processes occurring in warm mud fluids. The remaining bacterial phylotypes were related to alpha- and beta-Proteobacteria, Actinobacteria, Bacteroides, Deinococcus-Thermus, KB1 and OP-11 candidate divisions. Moreover, a novel monophyletic clade, deeply branched with unaffiliated 16S rDNA clones was also retrieved from deep-sea sediments and halocline of Urania Basin. Archaeal diversity was much lower and detected phylotypes included organisms affiliated exclusively with the Euryarchaeota. More than 96% of the archaeal clones belonged to the MSBL-1 candidate order recently found in hypersaline anoxic environments, such as endoevaporitic microbial mats, Mediterranean deep-sea mud volcanoes and anoxic basins. Two phylotypes, represented by single clones were related to uncultured groups DHVE-1 and ANME-1. Thus, the hydrothermal mud of hypersaline Urania Basin seems to contain new microbial diversity. The prokaryotic community was significantly different from that occurring in the upper layers of the Urania Basin since 60% of all bacterial and 40% of all archaeal phylotypes were obtained only from mud

  19. Multilevel eEmpirical Bayes modeling for improved estimation of toxicant formulations tosuppress parasitic sea lamprey in the Upper Great Lakes

    USGS Publications Warehouse

    Hatfield, Laura A.; Gutreuter, Steve; Boogaard, Michael A.; Carlin, Bradley P.

    2011-01-01

    Estimation of extreme quantal-response statistics, such as the concentration required to kill 99.9% of test subjects (LC99.9), remains a challenge in the presence of multiple covariates and complex study designs. Accurate and precise estimates of the LC99.9 for mixtures of toxicants are critical to ongoing control of a parasitic invasive species, the sea lamprey, in the Laurentian Great Lakes of North America. The toxicity of those chemicals is affected by local and temporal variations in water chemistry, which must be incorporated into the modeling. We develop multilevel empirical Bayes models for data from multiple laboratory studies. Our approach yields more accurate and precise estimation of the LC99.9 compared to alternative models considered. This study demonstrates that properly incorporating hierarchical structure in laboratory data yields better estimates of LC99.9 stream treatment values that are critical to larvae control in the field. In addition, out-of-sample prediction of the results of in situ tests reveals the presence of a latent seasonal effect not manifest in the laboratory studies, suggesting avenues for future study and illustrating the importance of dual consideration of both experimental and observational data.

  20. The 8.4 ka lake Agassiz drainage event: its deep-sea sedimentary record and impact on the Atlantic Meridional Overturning

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, C.; de Vernal, A.; Piper, D. J.; St-Onge, G.

    2005-12-01

    Many papers have linked the ca. 8.4 ka drainage of the Laurentide Ice Sheet pro-glacial Lake Agassiz (Barber et al, 2002, Nature 400, 344-348) to a significant reduction in the Atlantic Meridional Overturning (AMO) and to climate excursions of variable age and duration in the 8.5-8 ka time frame, with reference to the so-called "8.2 ka event" (see refs. in Rohling and Pelike, 2004, Nature 434, 975-979) based on the Greenland ice core chronology. Unfortunately, none of these papers provide direct marine evidence for a collapse or significant reduction in the AMO, neither for a widespread change in sea-surface conditions over the northern North Atlantic. Moreover, model experiments made with reference to this event lack critical evaluation based on data. Here, we present paleoceanographical records near the source area in the northwest North Atlantic with chronological resolution as high as 15 years per sample in some instances. They provide evidence for two short duration, local sedimentological events (possibly each of one year duration according to Clarke et al., 2003, Science 301, 922-923), but indicate the absence of significant change in sea-surface conditions as well as in the outflow of the deep Western Boundary Under Current, at the resolvable time scale. We conclude that there is no evidence for a significant change in the AMO linked to the drainage event that lasted more than a few tens of years, if at all. Nonetheless, all marine records indicate that the 8.5 to 7.5 ka time interval does correspond to a major large scale re-organisation both of land drainage in NE America and of the North Atlantic climate-ocean system (cf. St-Onge et al., 2003, EPSL 209, 113-130; Keigwin et al., 2005, Paleoceanography, 20, 10.1029/2004PA001074), notably marked by a reduction in the North East North Atlantic Water outflow, an increasing Denmark Strait Overflow and the inception of Labrador Sea Water formation.

  1. Sanctuaries for lake trout in the Great Lakes

    USGS Publications Warehouse

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

    1987-01-01

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

  2. Archaeal and bacterial communities respond differently to environmental gradients in anoxic sediments of a California hypersaline lake, the Salton Sea.

    PubMed

    Swan, Brandon K; Ehrhardt, Christopher J; Reifel, Kristen M; Moreno, Lilliana I; Valentine, David L

    2010-02-01

    Sulfidic, anoxic sediments of the moderately hypersaline Salton Sea contain gradients in salinity and carbon that potentially structure the sedimentary microbial community. We investigated the abundance, community structure, and diversity of Bacteria and Archaea along these gradients to further distinguish the ecologies of these domains outside their established physiological range. Quantitative PCR was used to enumerate 16S rRNA gene abundances of Bacteria, Archaea, and Crenarchaeota. Community structure and diversity were evaluated by terminal restriction fragment length polymorphism (T-RFLP), quantitative analysis of gene (16S rRNA) frequencies of dominant microorganisms, and cloning and sequencing of 16S rRNA. Archaea were numerically dominant at all depths and exhibited a lesser response to environmental gradients than that of Bacteria. The relative abundance of Crenarchaeota was low (0.4 to 22%) at all depths but increased with decreased carbon content and increased salinity. Salinity structured the bacterial community but exerted no significant control on archaeal community structure, which was weakly correlated with total carbon. Partial sequencing of archaeal 16S rRNA genes retrieved from three sediment depths revealed diverse communities of Euryarchaeota and Crenarchaeota, many of which were affiliated with groups previously described from marine sediments. The abundance of these groups across all depths suggests that many putative marine archaeal groups can tolerate elevated salinity (5.0 to 11.8% [wt/vol]) and persist under the anaerobic conditions present in Salton Sea sediments. The differential response of archaeal and bacterial communities to salinity and carbon patterns is consistent with the hypothesis that adaptations to energy stress and availability distinguish the ecologies of these domains.

  3. Snow Clouds Stream off Lake Michigan

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  4. 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 μg/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

  5. Controls on the pH of hyper-saline lakes - A lesson from the Dead Sea

    NASA Astrophysics Data System (ADS)

    Golan, Rotem; Gavrieli, Ittai; Ganor, Jiwchar; Lazar, Boaz

    2016-01-01

    The pH of aqueous environments is determined by the dominant buffer systems of the water, defined operationally as total alkalinity (TA). The major buffer systems in the modern ocean are carbonic and boric acids of which the species bicarbonate, carbonate and borate make up about 77%, 19% and 4% of the TA, respectively. During the course of seawater evaporation (e.g. lagoons) the residual brine loses considerable portion of the dissolved inorganic carbon (DIC) and carbonate alkalinity (CA) already at the early stages of evaporation. DIC and CA decrease due to massive precipitation of CaCO3, while total boron (TB) increases conservatively, turning borate to the dominant alkalinity species in marine derived brines. In the present work we assess the apparent dissociation constant value of boric acid (KB‧) in saline and hypersaline waters, using the Dead Sea (DS) as a case study. We explain the DS low pH (∼6.3) and the effect of the boric and carbonic acid pK‧-s on the behavior of the brine's buffer system, including the pH increase that results from brine dilution.

  6. 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.

  7. Stream-floodplain connectivity and fish assemblage diversity in the Champlain Valley, Vermont, U.S.A.

    PubMed

    Sullivan, S M P; Watzin, M C

    2009-05-01

    To evaluate the influence of main channel-floodplain connectivity on fish assemblage diversity in floodplains associated with streams and small rivers, fish assemblages and habitat characteristics were surveyed at 24 stream reaches in the Champlain Valley of Vermont, U.S.A. Fish assemblages differed markedly between the main channel and the floodplain. Fish assemblage diversity was greatest at reaches that exhibited high floodplain connectivity. Whereas certain species inhabited only main channels or floodplains, others utilized both main channel and floodplain habitats. Both floodplain fish alpha-diversity and gamma-diversity of the entire stream corridor were positively correlated with connectivity between the main channel and its floodplain. Consistent with these results, species turnover (as measured by beta-diversity) was negatively correlated with floodplain connectivity. Floodplains with waterbodies characterized by a wide range of water depths and turbidity levels exhibited high fish diversity. The results suggest that by separating rivers from their floodplains, incision and subsequent channel widening will have detrimental effects on multiple aspects of fish assemblage diversity across the stream-floodplain ecosystem.

  8. Lakes, Lagerstaetten, and Evolution

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

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

  9. 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.

  10. Introduction to the Proceedings of the 1994 International Conference on Restoration of Lake Trout in the Laurentian Great Lakes

    USGS Publications Warehouse

    Selgeby, James H.

    1995-01-01

    Lake trout (Salvelinus namaycush) restoration in the Great Lakes began in the 1950s when stocking of artificially propagated lake trout was coupled with the first attempts at sea lamprey (Petromyzon marinus) control. A major milestone in the restoration process was recorded when a selective sea lamprey larvicide was identified in 1958 (Applegate et al. 1958) and then applied broad scale in Lake Superior in 1958-60 (Applegate et al. 1961). Other milestones include the expansion of the sea lamprey control programs into Lakes Michigan and Huron in 1960 (sustained usage in Lake Huron began in 1966, Smith and Tibbles 1980), Lake Ontario in 1971-72 (Elrod et al. 1995), and Lake Erie in 1986 (Cornelius et al. 1995). Following the collapse of lake trout in the Great Lakes and the implementation of massive stocking of hatchery-reared fish and effective sea lamprey control, the first documented evidence of nearshore natural reproduction of lake trout was in Lake Superior in 1965 (Dryer and King 1968), in Lake Michigan in 1980 (Jude et al. 1981), in Lake Huron in 1981-82 (Nester and Poe 1984), and in Lake Ontario in 1986 (Marsden et al. 1988).

  11. The National Sea Grant Program.

    ERIC Educational Resources Information Center

    Spector, Barbara S.

    1980-01-01

    Described is the National Sea Grant College Program which supports education and training, research, and advisory extension services through the National Office of Sea Grant and the Sea Grant Network of 30 programs in coastal and Great Lake states. Water-related topics include water's relationship to nature, society, and human expression.…

  12. East Siberian Sea, Russia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  13. [Genetic Differentiation of Sockeye Salmon Oncorhynchus nerka from Kamchatka River Basin and the Lake-River Systems of the West Coast of the Bering Sea as Inferred from Data on Single Nucleotide Polymorphism].

    PubMed

    Khrustaleva, A M; Klovach, N V; Vedischeva, E V; Seeb, J E

    2015-10-01

    The variability of 45 single nucleotide polymorphism loci (SNP) was studied in sockeye salmon from the Kamchatka River basin and four lake-river systems of the west coast of the Bering Sea. Based on the genetic differentiation estimates for the largest sockeye salmon populations of Eastern Kamchatka and Chukotka, the examined samples were combined into two regional groups represented by the population of the Kamchatka River drainage, which included numerous local subpopulations and seasonal races, and the northern population grouping from the rivers of Olutorsko-Navarinsky raion, wherein the sockeye salmon from Maynypilginskaya Lake-River system was relatively isolated. Considerable divergence was observed between the island (Sarannoe Lake, Bering Island) and continental populations. Genetic heterogeneity was revealed and groups of early- and late-maturing individuals were isolated in the sample of late-run sockeye salmon from Kamchatka River. In Apuka River, subdivision of the spawning run into two genetically distinct spatial and temporal groupings was also observed. The results suggest that the differentiation of sockeye salmon samples by single nucleotide substitution frequencies was largely due to differences in the direction and strength of local selection at some loci in the population complexes and intrapopulation groupings from the examined river basins of Eastern Kamchatka, Chukotka, and Commander Islands.

  14. 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.

  15. 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)…

  16. Hydrology of Lake Butler, Orange County, Florida

    USGS Publications Warehouse

    Smoot, James L.; Schiffer, Donna M.

    1984-01-01

    Lake Butler is one of the lakes that collectively make up the Butler chain of lakes in the headwaters of the Kissimmee River, Florida. The bottom configuration of the lake is typical of relict karst features formed during lower stages in sea level. The top of the Floridan aquifer is 50 to 100 feet below the land surface. The drainage area of Lake Butler is approximately 14.5 sq mi and is comprised of sub-basins of other lakes in the vicinity. Surface outflow from Lake Butler is generally southward to Cypress Creek, a tributary of the Kissimmee River. The extremes in lake stage for the period 1933-81 are 94.67 ft on June 23, 1981 and 101.78 ft on September 13, 1960. The median lake stage for this period was 99.28 ft above sea level. The quality of water in Lake Butler is excellent, based on studies of physical, chemical, and biological conditions by the Orange County Pollution Control Department. The lake water is slightly acidic and soft (48 mg/L hardness as calcium carbonate). Pesticides in water were below detection levels at two sites sampled in the lake, but were detected in the bottom sediments. (USGS)

  17. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  18. 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.

  19. Progress toward lake trout restoration in Lake Michigan

    USGS Publications Warehouse

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

    1995-01-01

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

  20. Asynchronous ice lobe retreat and glacial Lake Bascom: Deglaciation of the Hoosic and Vermont valleys, southwestern Vermont

    SciTech Connect

    Small, E.; Desimone, D. . Dept. of Geology)

    1993-03-01

    Deglaciation of the Hoosic River drainage basin in southwestern Vermont was more complex than previously described. Detailed surficial mapping, stratigraphic relationships, and terrace levels/delta elevations reveal new details in the chronology of glacial Lake Bascom: (1) a pre-Wisconsinan proglacial lake was present in a similar position to Lake Bascom as ice advanced: (2) the northern margin of 275m (900 ft) glacial Lake Bascom extended 10 km up the Vermont Valley; (3) the 215m (705 ft) Bascom level was stable and long lived; (4) intermediate water planes existed between 215m and 190m (625 ft) levels; and (5) a separate ice tongue existed in Shaftsbury Hollow damming a small glacial lake, here named glacial Lake Emmons. This information is used to correlate ice margins to different lake levels. Distance of ice margin retreat during a lake level can be measured. Lake levels are then used as control points on a Lake Bascom relative time line to compare rate of retreat of different ice tongues. Correlation of ice margins to Bascom levels indicates ice retreat was asynchronous between nearby tongues in southwestern Vermont. The Vermont Valley ice tongue retreated between two and four times faster than the Hoosic Valley tongue during the Bascom 275m level. Rate of retreat of the Vermont Valley tongue slowed to one-half of the Hoosic tongue during the 215m--190m lake levels. Factors responsible for varying rates of retreat are subglacial bedrock gradient, proximity to the Hudson-Champlain lobe, and the presence of absence of a calving margins. Asynchronous retreat produced splayed ice margins in southwestern Vermont. Findings from this study do not support the model of parallel, synchronous retreat proposed by many workers for this region.

  1. Lake Tahoe

    EPA Pesticide Factsheets

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

  2. 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.

  3. Hg Deposition to Lakes in Northern New England Inferred at Multiple Scales From 210Pb-Dated Sediment Cores

    NASA Astrophysics Data System (ADS)

    Kamman, N. C.; Engstrom, D.

    2004-05-01

    Mercury (Hg) contamination of aquatic systems is recognized to be a problem of global consequence, and Hg bioaccumulation poses significant risks to piscivorous animals and humans who consume gamefish. In order to quantify historical and current Hg deposition to the northern New England landscape, we dated and performed Hg analyses on sediments cores from various lakes at local and regional scales. In this presentation, we contrast results of three studies: a regional assessment of Hg deposition to the VT-NH landscape (10 lakes); a localized study of deposition to the Lye Brook Wilderness of southern VT (four lakes); and the first-ever dated assessment of sediment Hg deposition history for Lake Champlain (three sites + one adjacent inland lake). At the VT-NH scale, total Hg (HgT) fluxes to sediments ranged from 5 to 17 μ g.m-2.yr-1 during pre-industrial times, and from 21 to 83 μ g.m-2.yr-1 presently. Present-day HgT fluxes are between 2.1 to 6.9 times greater than pre-1850 fluxes, and atmospheric Hg deposition to the VT-NH region was estimated at 21 μ g.m-2.yr-1. This agrees well with measured HgT deposition, when re-evasion of Hg is accounted for. Hg fluxes to lake sediments have declined in recent decades, owing to reductions in atmospheric Hg deposition to the lake surfaces. In the high-elevation Lye Brook Wilderness landscape, baseline, peak, and present accumulations were higher than those estimated from the VT-NH dataset, a finding that highlights the roles of elevation, watershed size, and dissolved organic carbon export in mediating Hg transport. Available data from the Lake Champlain Basin show the influence of historical and current watershed sediment delivery due to land cultivation, and more recently to land-use conversion. These studies jointly indicate that watershed export of legacy Hg continues despite declines in present-day deposition rates, contributing to the impression that Hg retention by watershed soils has declined.

  4. 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

  5. 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.

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

    USGS Publications Warehouse

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

    1998-01-01

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

  7. Lake fisheries need lamprey control and research

    USGS Publications Warehouse

    Moffett, James W.

    1953-01-01

    Since 1921, when the first sea lamprey was recorded from Lake Erie, concern about this parasite in the Great Lakes above Niagara Falls, where previously it had never occurred, grew successively. At first, the concern was shared only in scientific circles, but as the parasite continued its persistent and rapid spread throughout the upper Great Lakes this concern was voiced by state conservation departments, the U.S. Fish and Wildlife Service, and interested fishermen. Catches of lake trout especially, and other species secondarily, began to fall below anything representing normal fluctuations in abundance. The fishing industry on Lake Huron and Lake Michigan became extremely concerned due to the fact that income was diminishing greatly. Producers on Lake Superior were fearful that the same decline in production would soon characterize their fishery.

  8. Hydrology of Hunters Lake, Hernando County, Florida

    USGS Publications Warehouse

    Henderson, S.E.

    1986-01-01

    The size and shape of Hunters Lake, Florida has been significantly altered by development of the surrounding Spring Hill residential community. The lake is the largest in Hernando County, enlarged by lakeshore excavation and connection to nearby ponds to an area of 360 acres at an average stage of 17.2 ft above sea level. Hunters Lake is naturally a closed lake, but development of Spring Hill has resulted in a surface water outflow from the lake in its southwest corner. Inflow to the lake could occur on the east side during extreme high-water periods. The karst terrain of the Hunters Lake area is internally drained through permeable soils, depressions, and sinkholes, and natural surface drainage is absent. The underlying Floridan aquifer system is unconfined except locally near coastal springs. Flow in the groundwater system is to the west regionally and to the southwest in the immediate area of Hunters Lake. Water level gradients in the groundwater system increase from 1.4 ft/mi east of the lake to about 8 ft/mi southwest of the lake. Hunters Lake is hydraulically connected to the groundwater system, receiving groundwater on the northeast side and losing water to the groundwater system on the southwest side. This close relationship with the groundwater system is demonstrated by graphical and numerical comparison of Hunters Lake stage with water levels in nearby groundwater sites. During 1965-84, the stage of Hunters Lake fluctuated between 12.48 and 20.7 ft above sea level. Because area lakes are all directly affected by groundwater levels, they also show a close relationship with water levels in Hunters Lake. Analysis of water quality data for Hunters Lake indicates that the water of the lake is a soft calcium bicarbonate type with ionic concentrations higher than in water from nearby shallow wells and lower than in water from the Upper Floridan aquifer. Samples collected in 1981-1983 indicate slightly higher levels of ionic concentration than in 1965

  9. 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.

  10. 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)

  11. Water Budget and Salinity of Walker Lake, western Nevada

    USGS Publications Warehouse

    Thomas, James M.

    1995-01-01

    Walker Lake is one of the rare perennial, terminal lakes in the Great Basin of the western United States. The lake is the terminus for all surface- water and ground-water flow in the Walker River Basin Hydrographic Region that is not consumed by evaporation, sublimation, or transpiration. The concentration of dissolved solids (salts) in the lake-surface altitude depend primarily on the amounts of water entering and evaporation from the lake. Because Walker Lake is a terminal sink--it has no documented surface- or ground-water outflow--dissolved solids that enter it accumulate as the lake water evaporates. Declining lake levels, owing to natural and anthropogenic processes, have resulted in most Great Basin terminal lakes being too saline to support fish. In Nevada, the only terminal lakes that contain fish are Pyramid Lake, Ruby Lake, and Walker Lake. Dissolved-solids concentration in Walker Lake increased from about 2,500 milligrams per liter in 1882 to 13,300 milli- grams per liter in July 1994 (U.S. Geological Survey analysis), as the lake-surface altitude declined from about 4,080 to 3,944 feet above sea level. This dramatic increase in dissolved-solids concentration threatens the Walker Lake ecosystem and the fish that depend on this ecosystem.

  12. Traces of microbial activity in the deep sediment of the Dead Sea: How is life influencing the sedimentary record of this hypersaline lake ?

    NASA Astrophysics Data System (ADS)

    Thomas, Camille; Ebert, Yael; Kiro, Yael; Stein, Mordechai; Ariztegui, Daniel

    2016-04-01

    As part of the ICDP-sponsored Dead Sea Deep Drilling Project (DSDDP), a multi-disciplinary study has been carried out to understand the influence that microbial communities can have on the Dead Sea sedimentary record. Organic matter (lipids) and DNA extraction have been performed along the main core retrieved from the center of the modern Dead Sea. They revealed different associations of microbial communities, influenced by changing climatic and limnological regimes during sedimentation. Moreover, imaging and chemical characterization of authigenic iron-sulfur minerals have revealed the unexpected presence of an active sulfur cycle in the sediment. In particular, their morphology and Fe/S ratios are coherent with incomplete sulfate reduction, limited by sulfur reduction, and often resulting in the preservation of greigite. In glacial period intervals, pyritization may be complete, indicating full sulfate reduction probably allowed by significant accumulation of organic matter in the alternating aragonite and detritus (aad) facies. The DSDDP core provides a unique opportunity to investigate deep diagenetic processes and to assess the role of microbial activity in the Dead Sea hypersaline sediment. Our study shows that this microbial activity influences the carbon and sulfur phases, as well as magnetic fractions, potentially affecting proxies used for paleoenvironmental and paleoclimatic reconstructions.

  13. 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.

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

    EPA Pesticide Factsheets

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

  15. National Dam Safety Program. Main Mill Dam (Inventory Number N.Y. 262), Lake Champlain Basin, Clinton County, New York. Phase I Inspection Report,

    DTIC Science & Technology

    1981-09-21

    PZE P&CEM Phase~~~S I npetW Rpr OP REPORT 6 PERIOD COVZRSO Phas I nspctio ReortPhase I Inspection Repoct .gMain Mill Dai National. Dan& Safety Prosram...plain. Bedrock in the area is from the Ordovician era (435 to 500 million years ago). A review of the Brittle Structures Map of New York indicates that...1919. 607 W1’ (1,73 kei). PERIOD OP INCOR.--March 1903 to September 1930. October 1943 to current year. Published as "near Plattsburgh." 1903-30

  16. 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.

  17. Movement and recapture of parasitic-phase sea lampreys (Petromyzon marinus) tagged in the St. Marys River and Lakes Huron and Michigan, 1963-67

    USGS Publications Warehouse

    Moore, Harry H.; Dahl, Frederick H.; Lamsa, Aarne K.

    1974-01-01

    Four sea lampreys 345-445 mm long when tagged in November or early December were recovered in mid-September of the following year, at least 2 months after the end of the normal spawning season. Suggested possible reasons for this unusual occurrence are the extension of the parasitic phase of the life cycle beyond the usual 12 to 20 months, late-season maturation of the gonads, disease, or deleterious effects of the tags.

  18. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

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

  19. Archaea in Yellowstone Lake.

    PubMed

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

    2011-11-01

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

  20. Preferred temperatures of juvenile lake whitefish

    USGS Publications Warehouse

    Edsall, Thomas A.

    1999-01-01

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

  1. A coupled lake-atmosphere model (CLAM) and its application to Lake Kinneret

    NASA Astrophysics Data System (ADS)

    Pan, Hai

    1999-08-01

    Kinneret is a 166-km2 lake located in Northern Israel, in the central part of the Jordan Valley, a corridor running from north to south, between the Galilee hills in the west and the Golan Heights in the east. Both the Galilee hills and the Golan Heights reach an elevation of about 400 m above mean sea level (MSL), and the lake is about -210 m (MSL). North of the lake is the mountainous area of the Hermon, culminating at about 2800 m (MSL). About 120 km south of it is the Dead Sea, which is about -410 m (MSL), and about 45 km west of it is the Mediterranean Sea. The complexity of the terrain, combined with relatively arid soil and various ground covers surrounding the lake, results in a very complicated system of atmospheric and lake processes. To understand this system, especially the processes affecting the atmosphere and lake dynamics and thermodynamics, and their effects on Lake Kinneret evaporation, a coupled lake-atmosphere model (CLAM) was developed and applied to the lake region. The CLAM is based on the Regional Atmospheric Modeling System (RAMS) and the oceanic S-coordinate Rutgers University Model (SCRUM). Energy, mass, and momentum are conserved at the interface between the atmosphere and the lake, and appropriate balance equations are applied there. In the atmospheric module, two nested grids are employed to simulate Northern Israel at a resolution of 4 x 4 km2, and the near-lake region at a resolution of 1 x 1 km 2. Synoptic conditions obtained from the National Meteorological Center (NMC) reanalysis are assimilated by the model. Soil moisture, which appears to have a significant impact on atmospheric circulation in this region, was transformed from the normalized difference vegetation index (NDVI). Observations collected during two summers above and inside the lake emphasize the good capability of CLAM to simulate surface fluxes and other microclimatic conditions, as well as lake temperature and currents. Although the lake is small (about 12-km wide

  2. Supplemental Curriculum Activities for use with Holling Clancy Holling's "Paddle-to-the-Sea."

    ERIC Educational Resources Information Center

    Seager, Marcia L.; And Others

    Research has shown that middle school students in the Great Lakes region do not have a great deal of knowledge about the lakes. This has important implications when it comes to resources such as the Great Lakes. The story of "Paddle-to-the-Sea" offers an opportunity to learn about the Great Lakes Basin ecosystem in a meaningful and…

  3. [The parasite fauna from fishes of the Onega and Ladoga lakes (some features of resemblance and difference)].

    PubMed

    Rumiantsev, E A

    2002-01-01

    The presence of some glacial species in the parasite fauna of the Onega Lake and relict representatives of the Litorinic sea in the Ladoga Lake leads to the suggestion, that the first water basin did not undertake a strong influence of sea transgression and did not have an extensive connection with the sea.

  4. Gas exchange rates for three closed-basin lakes

    SciTech Connect

    Peng, T.H.; Broecker, W.

    1980-09-01

    Long term monitoring of the /sup 14/C:/sup 12/C ratio in three closed-basin lakes in the western United States has resulted in reliable estimates of the mean CO/sub 2/ invasion rates. When normalized to sea level pressure the results are 6 mol m/sup -/2 yr/sup -/1 for Pyramid Lake, 17 for Walker Lake, and 38 for Mono Lake. Except for Mono Lake, these bomb /sup 14/C-derived invasion rates are consistent with those derived from the distribution of natural radiocarbon. The big difference in the invasion rates estimated for Mono Lake by the two methods is attributed to the influx of /sup 14/C-free spring waters to the lake. Possible causes for the difference in CO/sub 2/ invasion rates among the three lakes are wind velocity, salinity, and pH.

  5. White Lake AOC

    EPA Pesticide Factsheets

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

  6. 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

  7. The Discovery of Stromatolites Developing at 3570 m above Sea Level in a High-Altitude Volcanic Lake Socompa, Argentinean Andes

    PubMed Central

    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

  8. 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.

    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.

  9. Hydrology, water quality, and nutrient loads to Lake Catherine and Channel Lake, near Antioch, Lake County, Illinois

    USGS Publications Warehouse

    Kay, Robert T.; Johnson, Gary P.; Schrader, David L.

    2000-01-01

    From April 21, 1998, through April 30, 1999, the U.S. Geological Survey, in cooperation with the Fox Waterway Agency, conducted an investigation designed to characterize the hydrology, water quality, hydrologic budget, sediment budget, and nutrient budget of Lake Catherine and Channel Lake, Lake County, Illinois. These lakes are the northernmost lakes of the Fox Chain of Lakes. Lake Catherine and Channel Lake are divided into two basins by a submerged ridge but are continuous at the surface. The lakes are marginally to moderately eutrophic. Lake Catherine and Channel Lake have a combined volume of 7,098 acre-feet at a stage of about 736.5 feet above sea level. Lake Catherine and Channel Lake are subject to thermal stratification. Although most of the water in the lakes is well oxidized, nearly anoxic conditions were present at the bottom of Lake Catherine and Channel Lake during part of the summer in 1998. Water enters Lake Catherine and Channel Lake as inflow from surface water in the watershed (61.9 percent), inflow through the State Highway 173 bridge openings (20.7 percent), direct precipitation (8.2 percent), inflow from storm drains (7.2 percent), and inflow of ground water (2.0 percent). Water exits Lake Catherine and Channel Lake as outflow through the State Highway 173 bridge openings (87.8 percent), evaporation (7.2 percent), and as outflow to ground water (5.0 percent). About 5,200 pounds of phosphorus and 107,200 pounds of nitrogen compounds were added to the lakes during the period of investigation. Phosphorus compounds were derived from primarily internal regeneration (40.2 percent), inflow from surface water in the watershed (30.9 percent), inflow from storm drains (12.5 percent), and inflow through the State Highway 173 bridge openings (9.8 percent). Inflowing ground water, waterfowl excrement, precipitation, and atmospheric deposition of particulate matter account for 6.6 percent of the phosphorus load. Nitrogen was derived from inflow of surface

  10. Basic limnology of fifty-one lakes in Costa Rica.

    PubMed

    Haberyan, Kurt A; Horn, Sally P; Umaña, Gerardo

    2003-03-01

    We visited 51 lakes in Costa Rica as part of a broad-based survey to document their physical and chemical characteristics and how these relate to the mode of formation and geographical distribution of the lakes. The four oxbow lakes were low in elevation and tended to be turbid, high in conductivity and CO2, but low in dissolved O2; one of these, L. Gandoca, had a hypolimnion essentially composed of sea water. These were similar to the four wetland lakes, but the latter instead had low conductivities and pH, and turbidity was often due to tannins rather than suspended sediments. The thirteen artificial lakes formed a very heterogenous group, whose features varied depending on local factors. The thirteen lakes dammed by landslides, lava flows, or lahars occurred in areas with steep slopes, and were more likely to be stratified than most other types of lakes. The eight lakes that occupy volcanic craters tended to be deep, stratified, clear, and cool; two of these, L. Hule and L. Río Cuarto, appeared to be oligomictic (tending toward meromictic). The nine glacial lakes, all located above 3440 m elevation near Cerro Chirripó, were clear, cold, dilute, and are probably polymictic. Cluster analysis resulted in three significant groups of lakes. Cluster 1 included four calcium-rich lakes (average 48 mg l-1), Cluster 2 included fourteen lakes with more Si than Ca+2 and higher Cl- than the other clusters, and Cluster 3 included the remaining thirty-three lakes that were generally less concentrated. Each cluster included lakes of various origins located in different geographical regions; these data indicate that, apart from the high-altitude glacial lakes and lakes in the Miravalles area, similarity in lake chemistry is independent of lake distribution.

  11. Hydrology of Lake Panasoffkee, Sumter County, Florida

    USGS Publications Warehouse

    Taylor, G.F.

    1977-01-01

    Lake Panasoffkee, in midwest Sumter County of central Florida, receives water from three creeks and discharges water through Outlet River at an average daily rate of 207 cubic feet per second. The eastern shore of the lake is marsh and wooded swamp with inflow to the lake coming from the northeast and southeast. About 15 percent of the basin contributes surface water to the lake and about 50 percent of the 420-square-mile topographic drainage basin contributes ground water to the lake. The water from the remainder of the basin either evaporates from low areas or directly recharges the Floridan aquifer for discharge outside the basin. The maximum stage on record is 44.28 feet above mean sea level and the minimum stage on record is 37.65 feet above. The lake level is partly affected by the Wysong Dam and has stabilized in recent years at about 40.95 feet above mean sea level. The quality of the water is generally good. The lake supports a favorably balanced fish population even though minor fish kills were reported in 1973 and 1974. These kills were probably the result of algal blooms. (Woodard-USGS)

  12. Lake Powell

    NASA Technical Reports Server (NTRS)

    2007-01-01

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

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

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

  13. Lake acidification

    SciTech Connect

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

    1987-06-01

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

  14. What are the cost savings associated with providing access to specialist care through the Champlain BASE eConsult service? A costing evaluation

    PubMed Central

    Liddy, Clare; Drosinis, Paul; Deri Armstrong, Catherine; McKellips, Fanny; Afkham, Amir; Keely, Erin

    2016-01-01

    Objective This study estimates the costs and potential savings associated with all eConsult cases completed between 1 April 2014 and 31 March 2015. Design Costing evaluation from the societal perspective estimating the costs and potential savings associated with all eConsults completed during the study period. Setting Champlain health region in Eastern Ontario, Canada. Population Primary care providers and specialists registered to use the eConsult service. Main outcome measures Costs included (1) delivery costs; (2) specialist remuneration; (3) costs associated with traditional (face-to-face) referrals initiated as a result of eConsult. Potential savings included (1) costs of traditional referrals avoided; (2) indirect patient savings through avoided travel and lost wages/productivity. Net potential societal cost savings were estimated by subtracting total costs from total potential savings. Results A total of 3487 eConsults were completed during the study period. In 40% of eConsults, a face-to-face specialist visit was originally contemplated but avoided as result of eConsult. In 3% of eConsults, a face-to-face specialist visit was not originally contemplated but was prompted as a result of the eConsult. From the societal perspective, total costs were estimated at $207 787 and total potential savings were $246 516. eConsult led to a net societal saving of $38 729 or $11 per eConsult. Conclusions Our findings demonstrate potential cost savings from the societal perspective, as patients avoided the travel costs and lost wages/productivity associated with face-to-face specialist visits. Greater savings are expected once we account for other costs such as avoided tests and visits and potential improved health outcomes associated with shorter wait times. Our findings are valuable for healthcare delivery decision-makers as they seek solutions to improve care in a patient-centred and efficient manner. PMID:27338880

  15. Recovery and decline of lake whitefish in U.S. waters of eastern Lake Ontario, 1980-2001

    USGS Publications Warehouse

    Owens, Randall W.; O'Gorman, Robert; Eckert, Thomas H.; Lantry, Brian F.; Dittman, Dawn E.

    2005-01-01

    The lake whitefish (Coregonus clupeaformis) was an important member of the native fish community and a valued commercial species in Lake Ontario. Lake whitefish were common in U.S. waters of the lake until 1965 and very abundant in Canadian waters through the early 1970s, although their numbers declined shortly thereafter. During 1975-1985, lake whitefish stocks remained depressed throughout the lake as a result of the combined effects of degraded water quality, overfishing, and predation. Rainbow smelt (Osmerus mordax) probably preyed on whitefish fry, and sea lamprey (Petromyzon marinus) preyed on adults. During 1985-1987, lake whitefish stocks began to recover in eastern Lake Ontario, and their buildup continued into the mid-1990s. Reasons for the recovery likely included control of the sea lamprey population and a reduction in the number of piscivorous rainbow smelt. By 1997, lake whitefish abundance had declined severely again; some fish appeared to have dispersed from the northeastern to the southeastern regions of the lake, and the depth of capture increased. We believe that the collapse of Diporeia spp. populations during 1992-1999 was responsible for the decline in the lake whitefish populations and the shifts in geographic and bathymetric distribution because lake whitefish fed primarily on Diporeia spp. After the collapse of Diporeia spp. populations, lake whitefish in southeastern Lake Ontario fed on Mysis relicta and quagga mussels (Dreissena bugensis). Changing from a diet of high-lipid Diporeia spp to low-lipid dreissenids and foraging on Mysis relicta at lower temperatures are apparently hampering the rebuilding of lake whitefish stocks.

  16. 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

  17. Heterogeneous glacial lake changes and links of lake expansions to the rapid thinning of adjacent glacier termini in the Himalayas

    NASA Astrophysics Data System (ADS)

    Song, Chunqiao; Sheng, Yongwei; Wang, Jida; Ke, Linghong; Madson, Austin; Nie, Yong

    2017-03-01

    Glacier mass loss in the Himalayas has far-reaching implications for the alteration of regional hydrologic regimes, an increased risk of glacial lake outburst, downstream water resource abundance, and contributions to sea level rise. However, the mass losses of Himalayan glaciers are not well understood towing to the scarcity of observations and the heterogeneous responses of Himalayan glaciers to climate change and local factors (e.g., glacier surge, interacting with proglacial lakes). In particular, there is a lack of understanding on the unique interactions between moraine-dammed glacial lakes and their effects on debris cover on valley glacier termini. In this study, we examined the temporal evolution of 151 large glacial lakes across the Himalayas and then classified these glacial lakes into three categories: proglacial lakes in contact with full or partial debris-covered glaciers (debris-contact lakes), ice cliff-contact lakes, and non-glacier-contact lakes. The results show that debris-contact lakes experienced a dramatic areal increase of 36.5% over the years 2000 to 2014, while the latter two categories of lakes remained generally stable. The majority of lake expansions occurred at the glacier front without marked lake level rises. This suggests that the rapid expansion of these debris-contact lakes can be largely attributed to the thinning of debris-covered ice as caused by the melting of glacial fronts and the subsequent glacial retreat. We reconstructed the height variations of glacier fronts in contact with 57 different proglacial lakes during the years 2000 to 2014. These reconstructed surface elevation changes of debris-covered, lake-contact glacier fronts reveal significant thinning trends with considerable lowering rates that range from 1.0 to 9.7 m/y. Our study reveals that a substantial average ice thinning of 3.9 m/y occurred at the glacier fronts that are in contact with glacial lakes.

  18. Lake Bonneville

    USGS Publications Warehouse

    Gilbert, Grove Karl

    1890-01-01

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

  19. Ups and Downs of Burbot and their predator Lake Trout in Lake Superior, 1953-2011

    USGS Publications Warehouse

    Gorman, Owen T.; Sitar, Shawn P.

    2013-01-01

    The fish community of Lake Superior has undergone a spectacular cycle of decline and recovery over the past 60 years. A combination of Sea Lamprey Petromyzon marinus depredation and commercial overfishing resulted in severe declines in Lake Trout Salvelinus namaycush, which served as the primary top predator of the community. Burbot Lota lota populations also declined as a result of Sea Lamprey depredation, largely owing to the loss of adult fish. After Sea Lamprey control measures were instituted in the early 1960s, Burbot populations rebounded rapidly but Lake Trout populations recovered more slowly and recovery was not fully evident until the mid-1980s. As Lake Trout populations recovered, Burbot populations began to decline, and predation on small Burbot was identified as the most likely cause. By 2000, Burbot densities had dropped below their nadir in the early 1960s and have continued to decline, with the densities of juveniles and small adults falling below that of large adults. Although Burbot populations are at record lows in Lake Superior, the density of large reproductive adults remains stable and a large reserve of adult Burbot is present in deep offshore waters. The combination of the Burbot's early maturation, long life span, and high fecundity provides the species with the resiliency to remain a viable member of the Lake Superior fish community into the foreseeable future.

  20. Global Change in the Great Lakes: Scenarios.

    ERIC Educational Resources Information Center

    Garrison, Barbara K., Ed.; Rosser, Arrye R., Ed.

    The Ohio Sea Grant Education Program has produced this series of publications designed to help people understand how global change may affect the Great Lakes region. The possible implications of global change for this region of the world are explained in the hope that policymakers and individuals will be more inclined to make responsible decisions…

  1. Lena River Delta and East Siberian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The winter sea ice in the east Siberian Sea is looking a bit like a cracked windshield in these true-color Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 16 and 23, 2002. North of the thawing tundra, the sea ice takes on its cracked, bright blue appearance as it thins, which allows the reflection of the water to show through. Numerous still-frozen lakes dot the tundra. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  2. 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.

  3. 19 CFR 4.83 - Trade between United States ports on the Great Lakes and other ports of the United States.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Lakes to or from any other port of the United States via the St. Lawrence River is intended to touch at... the Great Lakes via the Hudson River and otherwise than by sea, may operate under a document with...

  4. Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

    USGS Publications Warehouse

    Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

    2015-01-01

    Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

  5. Species succession and fishery exploitation in the Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1968-01-01

    The species composition of fish in the Great Lakes has undergone continual change since the earliest records. Some changes were caused by enrichment of the environment, but others primarily by an intensive and selective fishery for certain species. Major changes related to the fishery were less frequent before the late 1930's than in recent years and involved few species. Lake sturgeon (Acipenser fulvescens) were overexploited knowingly during the late 1800's because they interfered with fishing for preferred species; sturgeon were greatly reduced in all lakes by the early 1900's. Heavy exploitation accompanied sharp declines of lake herring (Leucichthys artedi) in Lake Erie during the 1920's and lake whitefish (Coregonus clupeaformis) in Lake Huron during the 1930's. A rapid succession of fish species in Lakes Huron, Michigan, and Superior that started about 1940 has been caused by selective predation by the sea lamprey (Petromyzon marinus) on native predatory species, and the resultant shifting emphasis of the fishery and species interaction as various species declined. Lake trout (Salvelinus namaycush) and burbot (Lota lota), the deepwater predators, were depleted first; this favored their prey, the chubs (Leucichthys spp.). The seven species of chubs were influenced differently according to differences in size. Fishing emphasis and predation by sea lampreys were selective for the largest species of chubs as lake trout and burbot declined. A single slow-growing chub, the bloater, was favored and increased, but as the large chubs declined the bloater was exploited by a new trawl fishery. The growth rate and size of the bloater increased, making it more vulnerable to conventional gillnet fishery and lamprey predation. This situation in Lakes Michigan and Huron favored the small alewife (Alosa pseudoharengus) which had recently become established in the upper Great Lakes, and the alewife increased rapidly and dominated the fish stocks of the lakes. The successive

  6. 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.

  7. Seiche oscillations in Lake Baikal

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  8. 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.

  9. GIS-modeling of an ice-dammed lake in the Lake Onega depression ca 14500-12500 Yrs BP

    NASA Astrophysics Data System (ADS)

    Subetto, Dmitry; Zobkov, Mikhail; Potakhin, Maksim; Tarasov, Aleksey

    2016-04-01

    Palaeogeographical reconstructions of the Onego ice-dammed lake development ca 14500-125000 yrs BP were based on the GIS approach. The palaeo-water-level surfaces were interpolated using a point-kriging approach. 14500-14000 Yrs BP: An ice-dammed lake occupied the southern part of the Lake Onega depression. The level of this lake was at 130-120 m a.s.l. and was controlled by a threshold of the water divide between the River Oshta and River Oyat', with discharge southwestward into the Oyat' basin. The surface area of the ice-dammed lake was 3500 sq.km. 14000-13300 Yrs BP: When the ice melted away from the mouth of the River Svir, the lake level dropped to 85-80 m a.s.l. and runoff was directed into the Lake Ladoga - easternmost part of The Baltic Ice Lake at that time. 13300-12500 Yrs BP: As the glacier retreated from the Lake Onega depression, the ice-dammed lake was occupied it and reached the maximum sizes (the surface area was 33000 sq.km). The new threshold in the northern part was opened and runoff was directed into the White Sea basin. During the conference new digital paleogeographical maps of the Onego ice-dammed lake will be presented. The study has been financially supported by the Russian Science Foundation (#14-17-00766).

  10. 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.

  11. 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.

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

    SciTech Connect

    Lesht, B. M.; Stroud, J. R.; McCormick, M. J.; Fahnenstiel, G. L.; Stein, M. L.; Welty, L. J.; Leshkevich, G. A.; Environmental Research; Univ. of Chicago; Great Lakes Research Lab.

    2002-04-15

    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.

  13. Evaporation from Lake Kinneret, Israel, during hot summer days

    NASA Astrophysics Data System (ADS)

    Shilo, Elad; Ziv, Baruch; Shamir, Eylon; Rimmer, Alon

    2015-09-01

    The relationships between the evaporation from a medium size (168.7 km2) Lake Kinneret (Northern Israel), and its governing synoptic factors are well demonstrated during the summer of 2010. During July-August the daily temperature of the air and water surface were ∼2-4 °C higher, the daily wind over the lake was ∼80% weaker, and the evaporation from the lake was ∼5% lower than the long-term July-August mean. In this study, we explore the impact of the regional and local synoptic-scale atmospheric conditions on the evaporation from the lake during exceptionally hot days in the mid-summer months (July-August). The factors that were found to be correlated with the lake evaporation are the temperatures at 850 hPa (negative) and 500 hPa (positive), the sea level pressure difference between Northern Egypt and Armenia (positive), and the height of the marine inversion (positive). Synoptic analysis indicates that two conditions are responsible for the reduction of the Mediterranean Sea Breeze (MSB) during exceptionally hot days, and consequently to the reduction of evaporation from the lake. First, the weakening of the permanent synoptic Etesian winds, which otherwise supports the inland penetration of the MSB; and second, the descent of the marine inversion to a height below the topographic ridge of the Galilee Mountains upwind of the study area, which blocks the Marine Sea Breeze from reaching Lake Kinneret.

  14. 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.

  15. Holocene Lake Records on Kamchatka

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  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

  17. Population dynamics of Lake Ontario lake trout during 1985-2007

    USGS Publications Warehouse

    Brenden, Travis O.; Bence, James R.; Lantry, Brian F.; Lantry, Jana R.; Schaner, Ted

    2011-01-01

    Lake trout Salvelinus namaycush were extirpated from Lake Ontario circa 1950 owing to commercial and recreational fishing, predation by sea lampreys Petromyzon marinus, and habitat degradation. Since the 1970s, substantial efforts have been devoted to reestablishing a self-sustaining population through stocking, sea lamprey control, and harvest reduction. Although a stocking-supported population has been established, only limited natural reproduction has been detected. Since the 1990s, surveys have indicated a continuing decline in overall abundance despite fairly static stocking levels. We constructed a statistical catch-at-age model to describe the dynamics of Lake Ontario lake trout from 1985 to 2007 and explore what factor(s) could be causing the declines in abundance. Model estimates indicated that abundance had declined by approximately 76% since 1985. The factor that appeared most responsible for this was an increase in age-1 natural mortality rates from approximately 0.9 to 2.5 between 1985 and 2002. The largest source of mortality for age-2 and older fish was sea lamprey predation, followed by natural and recreational fishing mortality. Exploitation was low, harvest levels being uncertain and categorized by length rather than age. Accurate predictions of fishery harvest and survey catch per unit effort were obtained despite low harvest levels by using atypical data (e.g., numbers stocked as an absolute measure of recruitment) and a flexible modeling approach. Flexible approaches such as this might allow similar assessments for a wide range of lightly exploited stocks. The mechanisms responsible for declining age-1 lake trout survival are unknown, but the declines were coincident with an increase in the proportion of stocked fish that were of the Seneca strain and a decrease in the overall stocking rate. It is possible that earlier studies suggesting that Seneca strain lake trout would be successful in Lake Ontario are no longer applicable given the large

  18. Lake Volta, Ghana

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  19. Fleet dynamics of the commercial lake trout fishery in Michigan waters of Lake Superior during 1929-1961

    USGS Publications Warehouse

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

    2004-01-01

    Understanding fishing fleet dynamics is important when using fishery dependent data to infer the status of fish stocks. We analyzed data from mandatory catch reports from the commercial lake trout (Salvelinus namaycush) fishery in Michigan waters of Lake Superior during 1929-1961, a period when lake trout populations collapsed through the combined effects of overfishing and sea lamprey (Petromyzon marinus) predation. The number of full-time fishermen increased during 1933-1943 and then decreased during 1943-1957. Addition of new fishermen was related to past yield, market prices, World War II draft exemptions, and lost fishing opportunities in Lake Huron and Lake Michigan. Loss of existing fishermen was related to declining lake trout density. Large mesh (a?Y 114-mm stretch-measure) gill net effort increased during 1929-1951 because fishermen fished more net inshore as lake trout density declined, even though catch per effort (CPE) was often higher in deeper waters. The most common gill net mesh size increased from 114-mm to 120-mm stretch-measure during 1929-1957, as lake trout growth increased. More effort was fished inshore than offshore and the amount of inshore effort was less variable over time than offshore effort. Relatively stable yield was maintained by increasing gill net effort and by moving some effort to better grounds. Because fishing-up caused yield and CPE to remain high despite declining lake trout abundance, caution must be used when basing goals for lake trout restoration on historical fishery indices.

  20. Late Stage 5 Glacio-isostatic Sea in the St. Lawrence Valley, Canada and United States

    USGS Publications Warehouse

    Occhietti, S.; Balescu, S.; Lamothe, M.; Clet, M.; Cronin, T.; Ferland, P.; Pichet, P.

    1996-01-01

    Although post-glacial marine sediments of late Wisconsinan and early Holocene age are common in eastern Canada and the northeastern United States, remnants of older Pleistocene marine sediments are scarce. A fossiliferous marine clay that predates the classical Wisconsinan was recently discovered in the St. Lawrence Valley. A dominantly estuarine environment is inferred from the geochemistry of the shells (??18O = -7.1) and from benthic foraminifer and ostracode assemblages. The clay indicates a marine invasion (Cartier Sea) shallower and probably shorter than that during the upper late Wisconsinan Champlain Sea episode (12,000-9,500 yr B.P.). The pollen content shows that regional vegetation during the marine episode began as open tundra, then became a Betula and Alnus crispa forest, reached a climatic optimum with Quercus, Corylus, and Abies, and concluded as a Pinus/Picea boreal forest. A corrected infrared stimulated luminescence age of 98,000 ?? 9000 yr is compatible with the epimerization ratio of shells. The Cartier Sea resulted from a post-glacial glacio-isostatic marine invasion in the St. Lawrence lowlands. It probably occurred during late stage 5 and is tentatively assigned to the transition of oxygen isotope substages 5b/5a. This marine episode dates to stage 5 of the preceding continental glacier which extended to middle latitudes in NE America. ?? 1996 University of Washington.

  1. Present state of the Aral Sea: diverging physical and biological characteristics of the residual basins

    PubMed Central

    Izhitskiy, A. S.; Zavialov, P. O.; Sapozhnikov, P. V.; Kirillin, G. B.; Grossart, H. P.; Kalinina, O. Y.; Zalota, A. K.; Goncharenko, I. V.; Kurbaniyazov, A. K.

    2016-01-01

    Latest data on the hydrophysical and biological state of the residual basins of the Aral Sea are presented and compared. Direct, quasi-simultaneous observations were carried out in the central part of the Western Large Aral Sea, the northern extremity of the Large Aral known as Chernyshev Bay, Lake Tshchebas, and the Small Aral Sea in October 2014. The Large Aral Sea and Lake Tshchebas transformed into hyperhaline water bodies with highly special taxocene structure. The Small Aral Sea was a relatively diverse brackish ecosystem, which was rather similar to the pre-desiccation environment. The Small Aral Sea and Lake Tshchebas exhibited a fully-mixed vertical structure, whereas the Western Large Aral Sea was strongly stratified. Our data show that during desiccation, different parts of the Aral Sea experienced different environmental conditions, resulting in qualitative and quantitative differences in the physical and biological regimes among the different residual basins. PMID:27032513

  2. Present state of the Aral Sea: diverging physical and biological characteristics of the residual basins

    NASA Astrophysics Data System (ADS)

    Izhitskiy, A. S.; Zavialov, P. O.; Sapozhnikov, P. V.; Kirillin, G. B.; Grossart, H. P.; Kalinina, O. Y.; Zalota, A. K.; Goncharenko, I. V.; Kurbaniyazov, A. K.

    2016-04-01

    Latest data on the hydrophysical and biological state of the residual basins of the Aral Sea are presented and compared. Direct, quasi-simultaneous observations were carried out in the central part of the Western Large Aral Sea, the northern extremity of the Large Aral known as Chernyshev Bay, Lake Tshchebas, and the Small Aral Sea in October 2014. The Large Aral Sea and Lake Tshchebas transformed into hyperhaline water bodies with highly special taxocene structure. The Small Aral Sea was a relatively diverse brackish ecosystem, which was rather similar to the pre-desiccation environment. The Small Aral Sea and Lake Tshchebas exhibited a fully-mixed vertical structure, whereas the Western Large Aral Sea was strongly stratified. Our data show that during desiccation, different parts of the Aral Sea experienced different environmental conditions, resulting in qualitative and quantitative differences in the physical and biological regimes among the different residual basins.

  3. Seismic reflection data from Lake Elsinore, Southern CA, reveal a sustained late-Holocene lake lowstand

    NASA Astrophysics Data System (ADS)

    Pyke, B. N.; Kirby, M. E.; Scholz, C. A.; Cattaneo, P.

    2009-12-01

    Lake Elsinore, located 120 kilometers southeast of Los Angeles, California, is Southern California’s largest natural lake. In December 2008, we collected over 75 km of high-resolution seismic reflection data using a CHIRP single-channel seismic-reflection Edgetech Geostar and the Geopulse™ Boomer systems. Initial interpretations reveal several interesting seismic sequences over the past 10,000 calendar years before present (cy BP: age control is based on dated sediment cores tied to the seismic lines). Most intriguing is evidence for a sustained interval of low lake level bracketed between ~ 3,000 and 1,800 cy BP. Prominent truncated stratal terminations characterize the upper boundary of this low stand seismic sequence. Sediment core data in the form of mudcracks, grain size variations, and geochemical data from various depositional environments (i.e., littoral and profundal) within Lake Elsinore support the seismic reflection interpretation for a low stand. Regionally, there is evidence for a similar interval of dry climate at Tulare Lake, the Mojave lakes, the Salton Sea, and possibly Dry Lake. A comparison to marine proxies along the eastern Pacific is less straight forward. The reason for this interval of sustained dry climate is not clear at this time. However, these results suggest that the already water-poor, over populated region of Southern California is subject to “droughts” of longer duration than that seen in the historical or tree-ring records from the region.

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

    SciTech Connect

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

    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.

  5. Fish community change in Lake Superior, 1970-2000

    USGS Publications Warehouse

    Bronte, Charles R.; Ebener, Mark P.; Schreiner, Donald R.; DeVault, David S.; Petzold, Michael M.; Jensen, Douglas A.; Richards, Carl; Lozano, Steven J.

    2003-01-01

    Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.

  6. Past, present and future of saline lakes: research for global sustainable development

    NASA Astrophysics Data System (ADS)

    Shadrin, Nickolai; Zheng, Mianping; Oren, Aharon

    2015-11-01

    The 12th International Conference on Salt Lake Research was held in Langfang City, China from July 14 to 18, 2014. Fifteen manuscripts of presentations have been retained for publication in this special issue. They are very diverse, covering the biology, physics, chemistry and geology of salt lakes, the history of hydrological research on the Dead Sea, the effects of socioeconomic and environmental policies by stakeholders on human populations, and the increasing salinization of freshwater lakes around the world.

  7. 46 CFR 42.03-15 - The Great Lakes of North America.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false The Great Lakes of North America. 42.03-15 Section 42.03... VOYAGES BY SEA Application § 42.03-15 The Great Lakes of North America. (a) The term “Great Lakes of North America” means those waters of North America which are defined in § 42.05-40, and in the exception...

  8. Lakes Ecosystem Services Online

    EPA Science Inventory

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

  9. National Lakes Assessment

    EPA Pesticide Factsheets

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

  10. Lake Huron LAMPs

    EPA Pesticide Factsheets

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

  11. Utah: Salt Lake Region

    Atmospheric Science Data Center

    2014-05-15

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

  12. The Great Lakes

    EPA Pesticide Factsheets

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

  13. About Lake Tahoe

    EPA Pesticide Factsheets

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

  14. Salish Sea

    EPA Pesticide Factsheets

    The Health of the Salish Sea Report is a collaboration between EPA and Environment Canada to examine the health of the Salish Sea ecosystem in Washington and British Columbia, encompassing the Puget Sound and Georgia Basin.

  15. Hydrogeology, hydrologic budget, and water chemistry of the Medina Lake area, Texas

    USGS Publications Warehouse

    Lambert, Rebecca B.; Grimm, Kenneth C.; Lee, Roger W.

    2000-01-01

    A three-phase study of the Medina Lake area in Texas was done to assess the hydrogeology and hydrology of Medina and Diversion Lakes combined (the lake system) and to determine what fraction of seepage losses from the lake system might enter the regional ground-water-flow system of the Edwards and (or) Trinity aquifers. Phase 1 consisted of revising the geologic framework for the Medina Lake area. Results of field mapping show that the upper member of the Glen Rose Limestone underlies Medina Lake and the intervening stream channel from the outflow of Medina Lake to the midpoint of Diversion Lake, where the Diversion Lake fault intersects Diversion Lake. A thin sequence of strata consisting primarily of the basal nodular and dolomitic members of the Kainer Formation of the Edwards Group, is present in the southern part of the study area. On the southern side of Medina Lake, the contact between the upper member of the Glen Rose Limestone and the basal nodular member is approximately 1,000 feet above mean sea level, and the contact between the basal nodular member and the dolomitic member is approximately 1,050 feet above mean sea level. The most porous and permeable part of the basal nodular member is about 1,045 feet above mean sea level. At these altitudes, Medina Lake is in hydrologic connection with rocks in the Edwards aquifer recharge zone, and Medina Lake appears to lose more water to the ground-water system along this bedding plane contact. Hydrologic budgets calculated during phase 2 for Medina Lake, Diversion Lake, and Medina/Diversion Lakes combined indicate that: (1) losses from Medina and Diversion Lakes can be quantified; (2) a portion of those losses are entering the Edwards aquifer; and (3) losses to the Trinity aquifer in the Medina Lake area are minimal and within the error of the hydrologic budgets. Hydrologic budgets based on streamflow, precipitation, evaporation, and change in lake storage were used to quantify losses (recharge) to the ground

  16. A Killer Lake

    ERIC Educational Resources Information Center

    Horvath, Thomas

    2005-01-01

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

  17. Lake Layers: Stratification.

    ERIC Educational Resources Information Center

    Brothers, Chris; And Others

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

  18. 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…

  19. 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)

  20. 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…

  1. Genetic diversity of wild and hatchery lake trout populations: Relevance for management and restoration in the Great Lakes

    USGS Publications Warehouse

    Page, K.S.; Scribner, K.T.; Burnham-Curtis, M.

    2004-01-01

    The biological diversity of lake trout Salvelinus namaycush in the upper Great Lakes was historically high, consisting of many recognizable morphological types and discrete spawning populations. During the 1950s and 1960s, lake trout populations were extirpated from much of the Great Lakes primarily as a result of overfishing and predation by the parasitic sea lamprey Petromyzon marinus. Investigations of how genetic diversity is partitioned among remnant wild lake trout populations and hatchery broodstocks have been advocated to guide lake trout management and conservation planning. Using microsatellite genetic markers, we estimated measures of genetic diversity and the apportionment of genetic variance among 6 hatchery broodstocks and 10 wild populations representing three morphotypes (lean, humper, and siscowet). Analyses revealed that different hatchery broodstocks and wild populations contributed disproportionally to the total levels of genetic diversity. The genetic affinities of hatchery lake trout reflected the lake basins of origin of the wild source populations. The variance in allele frequency over all sampled extant wild populations was apportioned primarily on the basis of morphotype (??MT = 0.029) and secondarily among geographically dispersed populations within each morphotype (??ST = 0.024). The findings suggest that the genetic divergence reflected in recognized morphotypes and the associated ecological and physiological specialization occurred prior to the partitioning of large proglacial lakes into the Great Lakes or as a consequence of higher contemporary levels of gene flow within than among morphotypes. Information on the relative contributions of different broodstocks to total gene diversity within the regional hatchery program can be used to prioritize the broodstocks to be retained and to guide future stocking strategies. The findings highlight the importance of ecological and phenotypic diversity in Great Lakes fish communities and

  2. The Use of Enzyme Hydrolysis to Assess the Seasonal Mobility and Bioavailability of Organic Phosphorus in Lake Sediments

    NASA Astrophysics Data System (ADS)

    Giles, C. D.; Lee, L. G.; Cade-Menun, B. J.; Rutila, B. C.; Schroth, A. W.; Xu, Y.; Hill, J. E.; Druschel, G.

    2013-12-01

    Lake sediments represent a significant internal source of phosphorus (P) in eutrophic freshwater systems during periods of high biological activity and oxygen depletion in sediments. Enzyme-labile and redox-sensitive P fractions may be a major component of the mobile sediment P pool which contributes to the development of harmful algal blooms. We present a high-through-put enzyme-based method for assessing potentially bioavailable (enzyme-labile) P in lake sediments and describe the relationship between enzyme-labile P, ascorbate-extractable (reactive) P and metals (Fe, Mn, Al, Ca), and P species identified using solution 31-P NMR spectroscopy. Sediment cores (0-10 cm) were collected from Lake Champlain over multiple years (Missisquoi Bay, VT, USA; 2007-2013). A principal components analysis of sediment properties suggests that enzyme-labile and reactive P, Mn, and Fe concentrations were more effective than the 31-P NMR methodology alone for differentiating algal bloom stage associated with periods of sediment anoxia. Bloom onset (July 2008) and peak bloom (August 2008, 2012) periods corresponded to the highest enzyme-labile P and lowest reactive P and metals proportions, despite 31-P NMR profiles which did not change significantly with respect to time and depth. High levels of reduced Fe and Mn ions were also detected in pore-water during this period, confirming previous reports that organic P bioavailability is linked to the redox status of sediments. High through-put analysis of enzyme-labile P fractions will provide spatially and temporally resolved information on bioavailable P pools at lower cost than traditional methods (i.e., 31-P NMR), and provide much-needed detail on aquatic P cycles during discrete stages of algal bloom development and sediment anoxia.

  3. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 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 ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  4. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The skies of the Bering Sea were relatively clear again in this SeaWiFS image showing a band of aquamarine colored water. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  5. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Much of the Bering Sea is clear in this SeaWiFS image. The large expanse of bright aquamarine water is clearly visible. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  6. Complete Genome Sequence of pAP13, a Large Linear Plasmid of a Brevibacterium Strain Isolated from a Saline Lake at 4,200 Meters above Sea Level in Argentina

    PubMed Central

    Schuldes, Jörg; Thürmer, Andrea; Farias, María E.; Daniel, Rolf; Meinhardt, Friedhelm

    2013-01-01

    pAP13 is an 89-kb linear plasmid hosted by Brevibacterium sp. strain Ap13, an actinobacterium isolated from the feces of a flamingo from an extremely high-altitude lake in Argentina. Because of the ecological importance of the genus Brevibacterium, the absolute lack of information concerning Brevibacterium linear plasmids, and the possible ecological significance of this unusual plasmid, pAP13 was completely sequenced, including the inversely oriented termini. PMID:24285657

  7. Physicochemical Characterization of Coarse Lake Spray Aerosol Particle from Lake Michigan

    NASA Astrophysics Data System (ADS)

    Ault, A. P.; Axson, J. L.; May, N.; Pratt, K.; Colon-Bernal, I. D.

    2015-12-01

    Wave breaking across bodies of water releases coarse particles into the air which can impact climate and human health. Freshwater lakes, such as the Great Lakes, can generate lake spray aerosols (LSA), similarly to how sea spray is generated, during periods of high winds and wave action. This LSA has the potential to impact climate through direct and indirect effects (ie. scattering/absorption and cloud nucleation) and are suggested to impact human health via inhalation of these particles during algal bloom periods characterized by toxic cyanobacteria. Very few studies have been conducted to assess the physicochemical properties of freshwater LSA. Prior work in our lab included the construction and characterization of a laboratory based LSA generator. In this work, we examine laboratory generated aerosol particles from laboratory based freshwater standards, freshwater samples collected from Lake Michigan, and ambient particles collected during a wave event on the shores of Lake Michigan in the summer of 2015. Particle size distributions, number concentrations, and chemical composition are presented and discussed as a function of laboratory generated and ambient collected LSA. Results indicate that there are characteristic particles that represent LSA. This study represents the next step towards evaluating and understanding the potential for coarse LSA to impact climate and health in the Great Lakes region.

  8. Microbial Diversity in Water and Sediment of Lake Chaka, an Athalassohaline Lake in Northwestern China

    PubMed Central

    Jiang, Hongchen; Dong, Hailiang; Zhang, Gengxin; Yu, Bingsong; Chapman, Leah R.; Fields, Matthew W.

    2006-01-01

    We employed culture-dependent and -independent techniques to study microbial diversity in Lake Chaka, a unique hypersaline lake (32.5% salinity) in northwest China. It is situated at 3,214 m above sea level in a dry climate. The average water depth is 2 to 3 cm. Halophilic isolates were obtained from the lake water, and halotolerant isolates were obtained from the shallow sediment. The isolates exhibited resistance to UV and gamma radiation. Microbial abundance in the sediments ranged from 108 cells/g at the water-sediment interface to 107 cells/g at a sediment depth of 42 cm. A major change in the bacterial community composition was observed across the interface. In the lake water, clone sequences affiliated with the Bacteroidetes were the most abundant, whereas in the sediments, sequences related to low G+C gram-positive bacteria were predominant. A similar change was also present in the archaeal community. While all archaeal clone sequences in the lake water belonged to the Halobacteriales, the majority of the sequences in the sediments were related to those previously obtained from methanogenic soils and sediments. The observed changes in the microbial community structure across the water-sediment interface were correlated with a decrease in salinity from the lake water (32.5%) to the sediments (approximately 4%). Across the interface, the redox state also changed from oxic to anoxic and may also have contributed to the observed shift in the microbial community. PMID:16751487

  9. Biogeochemistry of silica in Devils Lake: Implications for diatom preservation

    USGS Publications Warehouse

    Lent, R.M.; Lyons, B.

    2001-01-01

    Diatom-salinity records from sediment cores have been used to construct climate records of saline-lake basins. In many cases, this has been done without thorough understanding of the preservation potential of the diatoms in the sediments through time. The purpose of this study was to determine the biogeochemistry of silica in Devils Lake and evaluate the potential effects of silica cycling on diatom preservation. During the period of record, 1867-1999, lake levels have fluctuated from 427 m above sea level in 1940 to 441.1 m above sea level in 1999. The biogeochemistry of silica in Devils Lake is dominated by internal cycling. During the early 1990s when lake levels were relatively high, about 94% of the biogenic silica (BSi) produced in Devils Lake was recycled in the water column before burial. About 42% of the BSi that was incorporated in bottom sediments was dissolved and diffused back into the lake, and the remaining 58% was buried. Therefore, the BSi accumulation rate was about 3% of the BSi assimilation rate. Generally, the results obtained from this study are similar to those obtained from studies of the biogeochemistry of silica in large oligotrophic lakes and the open ocean where most of the BSi produced is recycled in surface water. During the mid 1960s when lake levels were relatively low, BSi assimilation and water-column dissolution rates were much higher than when lake levels were high. The BSi assimilation rate was as much as three times higher during low lake levels. Even with the much higher BSi assimilation rate, the BSi accumulation rate was about three times lower because the BSi water-column dissolution rate was more than 99% of the BSi assimilation rate compared to 94% during high lake levels. Variations in the biogeochemistry of silica with lake level have important implications for paleolimnologic studies. Increased BSi water-column dissolution during decreasing lake levels may alter the diatom-salinity record by selectively removing the

  10. An isotopic and chemical study of Lake Vanda and Don Juan Pond, Antarctica

    NASA Astrophysics Data System (ADS)

    Friedman, I.; Rafter, A.; Smith, G. I.

    Temperature measurements made in Lake Vanda and in the lake subbottom sediments show that the high temperatures in the lake are not due to geothermal heat flow, but are probably trapped solar energy. On the basis of Sr-87/86 ratios the salts in Lake Vanda can be derived by a mixture of 58% weathered rock plus 42% from sea water or precipitation. Loss of efflorescences high in sodium, potassium and magnesium by high winds can yield the salt compositions present in both Lake Vanda and Don Juan Pond. From isotopic data on deuterium, O-18, C-13, Sr-87/86, S-34 as well as from chemical data on Lake Vanda waters, interstitial brines contained in the subsurface sediment and C-14 dates a lake history is proposed.

  11. Upper Pleistocene and Holocene lakes in the An Nafud, Saudi Arabia

    USGS Publications Warehouse

    Schulz, E.; Whitney, J.W.

    1986-01-01

    Two major lake periods were discovered in the sand sea of An Nafud and the surrounding areas. In Upper Pleistocene large lakes occurred around the dune area and in the interior of the sand sea. Their deposits were formed between 34 000 and 24 000 BP. The lakes were not conformous to the present dune relief. They had an extension of several km2 and a depth of ca. 10 m. Holocene lakes (8 400-5 400 BP) were of minor extension and restricted to the interdune depressions. Lake sediments consist of cemented sand, calcareous crusts and diatomites. Upper Pleistocene lakes were fresh water lakes, the Halocene lakes were mostly swamps depending on rising and falling aquifers in the dunes. Plant remains as pollen and macro rests show that the environmental changes didn't exceed the system of semidesert comparable to the modern plant cover. However, the Upper Pleistocene lake deposits contain some more soudanian elements as the Holocene sediments in the pollen spectra. Climatically the lake formations are interpreted as depending on a stronger influence of the mediterranean cyclones or an interaction of them with monsoonal air masses. ?? 1986 Dr W. Junk Publishers.

  12. Hazardous crater lakes studied

    NASA Astrophysics Data System (ADS)

    Kusakabe, Minoru

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

  13. The hydrology of Lake Rousseau, west-central Florida

    USGS Publications Warehouse

    German, E.R.

    1978-01-01

    Lake Rousseau, about 4 miles southwest of Inglis, Florida, was formed in 1909 by impoundment of the Withlacooche River by Inglis Dam, west of Dunnellon, Florida. The lake was to have been part of the Cross-Florida Barge Canal; a lock and channel associated with the presently inactive project were completed in 1969. Lake Rousseau is about 11 miles long, covers about 4,000 acres, and contains about 34,000 acre-feet of water at the normal pool elevation of 27.5 feet above mean sea level. Inflow to the lake is relatively constant and responds slowly to rainfall. The estimated 100-year peak inflow, 10,400 cubic feet per second, is only 19 percent higher than the 100-year high monthly inflow. Water in Lake Rousseau is a calcium-bicarbonate type and is hard. Mean total phosphorus and organic nitrogen concentrations are considerably lower in Lake Rousseau than in north-central Florida lakes which have been considered to be eutrophic by other investigators, however, the lake supports of prolific aquatic plant community. Dissolved-oxygen concentrations near the water surface are occasionally less than 3 mg/liter. (Woodard-USGS)

  14. Partitioning potential fish yields from the Great Lakes

    USGS Publications Warehouse

    Loftus, D.H.; Olver, C.H.; Brown, Edward H.; Colby, P.J.; Hartman, Wilbur L.; Schupp, D.H.

    1987-01-01

    We proposed and implemented procedures for partitioning future fish yields from the Great Lakes into taxonomic components. These projections are intended as guidelines for Great Lakes resource managers and scientists. Attainment of projected yields depends on restoration of stable fish communities containing some large piscivores that will use prey efficiently, continuation of control of the sea lamprey (Petromyzon marinus), and restoration of high-quality fish habitat. Because Great Lakes fish communities were harmonic before their collapse, we used their historic yield properties as part of the basis for projecting potential yields of rehabilitated communities. This use is qualified, however, because of possible inaccuracies in the wholly commercial yield data, the presence now of greatly expanded sport fisheries that affect yield composition and magnitude, and some possibly irreversible changes since the 1950s in the various fish communities themselves. We predict that total yields from Lakes Superior, Huron, and Ontario will be increased through rehabilitation, while those from Lakes Michigan and Erie will decline. Salmonines and coregonines will dominate future yields from the upper lakes. The Lake Erie fishery will continue to yield mostly rainbow smelt (Osmerus mordax), but the relative importance of percids, especially of walleye (Stizostedion vitreum vitreum) will increase. In Lake Ontario, yields of salmonines will be increased. Managers will have to apply the most rigorous management strictures to major predator species.

  15. 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.

  16. Treatment of East Bay, Alger County, Michigan, with toxaphene for control of sea lampreys

    USGS Publications Warehouse

    Gaylord, William E.; Smith, Bernard R.

    1966-01-01

    An experiment was conducted to determine whether toxaphene can be used to eradicate lake-dwelling sea lampreys and to determine its effect on fish populations. In East Bay, a 78-acre lake on the Sucker River, Alger County, Mich., an estimated concentration of 100 parts per billion was maintained for 14 days. The sea lamprey larvae were more resistant to toxaphene than were the fish, but a complete kill was indicated. One year after treatment, sea lampreys were absent from the lake, while the fish population had recovered.

  17. 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.

  18. Isolated history of the coastal plant Lathyrus japonicus (Leguminosae) in Lake Biwa, an ancient freshwater lake

    PubMed Central

    Ohtsuki, Tatsuo; Kaneko, Yuko; Setoguchi, Hiroaki

    2011-01-01

    Background and aims Lake Biwa is one of the world's few ancient lakes. Formed ∼4 million years ago, the lake harbours many coastal species that commonly inhabit seashores. The beach pea Lathyrus japonicus is a typical coastal species of this freshwater lake, but its inland populations are faced with the threat of extinction. Here, we investigated the phylogeographical and population structures of both inland and coastal populations of L. japonicus. We also elucidated the historical isolation of the Lake Biwa population. Methodology In total, 520 individuals from 50 L. japonicus populations were sampled throughout the species distribution in Japan. Chloroplast haplotyping using intergenic spacers psbA–trnH and atpI–atpH was performed to investigate the phylogeographical structure as well as the genetic diversity of L. japonicus. Six nuclear microsatellite markers were also used to analyse the population structure. Principal results Population structure analyses of chloroplast DNA (cpDNA) and nuclear DNA (nDNA) identified inland and coastal groups. Based on the genetic differentiation, inland populations exhibited a single cpDNA haplotype and significantly lower values of HS, AR and FIS than coastal populations. In addition to the presence of a bottleneck, the lack of gene flow among inland populations was supported by estimates of recent migration rates between subpopulations. Conclusions Our data revealed that inland populations have been isolated in Lake Biwa as ‘landlocked’ populations since the predecessor lake was isolated from sea. This was also seen in a previous study of Calystegia soldanella. However, the high genetic differentiation, accompanied by a lack of gene flow among the Lake Biwa populations (according to the BAYESASS+ analysis), contradicts the results with C. soldanella. We conclude that because of the presence of a bottleneck and low genetic diversity of the inland populations, self-sustaining population persistence may be difficult in

  19. Dead Sea rhodopsins revisited.

    PubMed

    Bodaker, Idan; Suzuki, Marcelino T; Oren, Aharon; Béjà, Oded

    2012-12-01

    The Dead Sea is a unique hypersaline ecosystem with near toxic magnesium levels (∼2 M), dominance of divalent cations and a slightly acidic pH. Previously, we reported a haloarchaeon related to Halobacterium salinarum to dominate in a microbial bloom that developed in 1992 in the upper water layers of the lake following massive freshwater runoff. Whether this clade also dominated an earlier bloom in 1980-1982 cannot be ascertained as no samples for cultivation-independent analysis were preserved. The presence of the light-driven proton pump bacteriorhodopsin was reported in the 1980-1982 bloom of prokaryotes that had developed in the Dead Sea. To test the hypothesis that bacteriorhodopsin proton pumping may play a major role in determining what type of haloarchaea may dominate in specific bloom conditions, we compared rhodopsin genes recovered from Dead Sea biomass collected in different periods with genes coding for retinal proteins in isolated haloarchaea. Novel bacteriorhodopsin and sensory rhodopsin genes were found in samples collected in 2007 and 2010. The fact that no rhodopsin genes were recovered from samples collected during the 1992 bloom, which was dominated by a single species, suggests that different clades were present in the 1980-1982 and 1992 blooms, and that bacteriorhodopsin proton pumping did not necessarily play a determinative role in the dominance of specific halophiles in the blooms.

  20. Reproductive potential and fecundity of lake trout strains in southern and eastern waters of Lake Ontario, 1977-1994

    USGS Publications Warehouse

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

    1998-01-01

    We assessed the reproductive potential of various genetic strains of hatchery lake trout (Salvelinus namaycush) in southern and eastern Lake Ontario from indices of fecundity and indices of male abundance. Indices were constructed from catches of mature lake trout in gill nets during September 1980 to 1994 after correcting for mortality from sea lampreys (Petromyzon marinus) which occurred between September sampling and late fall spawning. Strain and age were assigned to individual lake trout based on clipped fins and maxillary bones or coded wire tags. Fecundity-length relationships for fish of the same age, determined from mature females collected in 1977 to 1981 and 1994, were not different (P > 0.05) among genetic strains. For all strains combined, fecundity-length relationships in 1977 to 1981 were not different among fish of various ages but in 1994, age-5 and -6 fish had fewer eggs (P < 0.003) than age-7 fish, and age-7 fish had fewer eggs (P < 0.003) than fish of age 8, 9, or 10. Annual indices of fecundity varied 19 fold and indices of mature males varied 11 fold; both indices were low in the early 1980s, increased sharply in the mid 1980s, and peaked in 1993. The strain which dominated fecundity and mature male indices shifted during the study from Seneca Lake strain to Lake Superior strain and then back to Seneca Lake strain. However, changes in either reproductive potential or genotypes do not appear responsible for the abrupt appearance of naturally-produced yearling lake trout throughout southern and eastern Lake Ontario in 1994–1995, the first widespread occurrence of juveniles produced by hatchery lake trout in Lake Ontario.

  1. Ecology of the Lake Huron fish community, 1970-1999

    USGS Publications Warehouse

    Dobiesz, Norine E.; McLeish, David A.; Eshenroder, Randy L.; Bence, James R.; Mohr, Lloyd C.; Ebener, Mark P.; Nalepa, Thomas F.; Woldt, Aaron P.; Johnson, James E.; Argyle, Ray L.; Makarewicz, Joseph C.

    2005-01-01

    We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but intensive control efforts on the St. Mary's River may reduce their predation on salmonines. Overfishing was less of a problem than in the past, although fishing continued to reduce the amount of lake trout (Salvelinus namaycush) spawning biomass resulting from hatchery-reared fish planted to rehabilitate this species. Massive stocking programs have increased the abundance of top predators, but lake trout were rehabilitated in only one area. Successful lake trout rehabilitation may require lower densities of introduced pelagic prey fish than were seen in the 1990s, along with continued stocking of hatchery-reared lake trout and control of sea lamprey. Such reductions in prey fish could limit Pacific salmon (Oncorhynchus spp.) fisheries.

  2. Salting our freshwater lakes.

    PubMed

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

    2017-04-10

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

  3. Postglacial paleoceanographic environments in the Barents and Baltic seas

    NASA Astrophysics Data System (ADS)

    Ivanova, E. V.; Murdmaa, I. O.; Emelyanov, E. M.; Seitkalieva, E. A.; Radionova, E. P.; Alekhina, G. N.; Sloistov, S. M.

    2016-01-01

    This paper presents reconstructions of ice sheet boundaries, lacustrine and marine paleobasins, as well as the connections of the Barents and Baltic seas with the North Atlantic from the Last Glacial Maximum to the Holocene. The reconstructions are based on original and published data obtained from the northern and western parts of the Barents Sea and Baltic depressions with account for the available regional schematic maps of deglaciation. The early deglaciation of the Scandinavian-Barents ice sheet culminated with the Bølling-Allerød interstadial (14.5-12.9 cal ka BP), which was characterized by a more vigorous Atlantic meridional overturning circulation (AMOC) and a corresponding increase in surface Atlantic water inflow into the Barents Sea through deep troughs. The Baltic Ice Lake (BIL) remained a dammed-up isolated basin during deglaciation from 16.0 to 11.7 cal ka BP. In the Younger Dryas (YD), the lake drained into the North Sea and was replaced by a brackish Yoldia Sea (YS) at the beginning of the Holocene (Preboreal, 11.7-10.7 cal ka BP), due to a limited connection between two basins through the Närke Strait. In the Barents Sea, the next increase in the Atlantic water influx into the deep basins corresponded to terminal YD and Preboreal events with a culmination in the Early Holocene. The Yoldia Sea became a lake again during the next stage, the Ancylus (~10.7-8.8 cal ka BP). Atlantic water inflow both into the Barents and Baltic seas varied during the Holocene, with a maximum contribution in the Early Holocene, when the Littorina Sea (LS, 8-4 cal ka BP) connection with the North Sea via the Danish Straits was formed to replace the Ancylus Lake. The recent, post-Littorina stage (PS, the last 4 cal ka) of the Baltic Sea evolution began in the Late Holocene.

  4. 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

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

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

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

  6. Bathymetry of Lake Michie, Durham County, North Carolina, 1990-92

    USGS Publications Warehouse

    Weaver, J. Curtis

    1993-01-01

    This map report presents the results of a bathymetric survey conducted as part of a 1990-92 study on the effects of sedimentation on Lake Michie, located in northeastern Durham County, North Carolina. Bathymetric data collected at the lake during 1990-92 indicate that, under normal pool conditions at the spillway elevation of 341.0 feet above sea level, the storage volume is 11,070 acre-feet, and the surface area is 508.7 acres. The maximum depth recorded in the lake was 75 feet at approximately 500 feet upstream of Lake Michie Dam.

  7. Origins of rainbow smelt in Lake Ontario

    USGS Publications Warehouse

    Bergstedt, Roger A.

    1983-01-01

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

  8. Speciation in ancient lakes.

    PubMed

    Martens, K

    1997-05-01

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

  9. Hydrology of Indiana lakes

    USGS Publications Warehouse

    Perrey, Joseph Irving; Corbett, Don Melvin

    1956-01-01

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

  10. Aerosol Production from the Great Lakes Surface

    NASA Astrophysics Data System (ADS)

    Slade, J. H.; Mwaniki, G.; Bertman, S. B.; Vanreken, T. M.; Shepson, P. B.

    2009-12-01

    It is well understood that oceans generate airborne particulate matter from mechanical processes such as sea spray and bubble bursting. These particles are primarily composed of salts and other nonvolatile inorganic material; however, the organic mass fraction can vary by location and the extent of biological activity. The size distributions of aerosols in these environments depend greatly on relative humidity with diameters ranging from typically several hundred nanometers to several micrometers. There has been much less discussion of particle formation from fresh water ecosystems, a hub for organic activity, and thus a more likely medium for organic aerosol production. We investigated particle formation over the Great Lakes during the summer of 2009 as a part of the Community Atmosphere-Biosphere Interactions Experiments (CABINEX) at the University of Michigan Biological Station (UMBS) in Pellston, MI. With a scanning mobility particle sizer (SMPS) aboard Purdue University’s Airborne Laboratory for Atmospheric Research (ALAR) for size-distribution analysis of accumulation-mode aerosol, we conducted vertical profiles above Lake Michigan and the UMBS deciduous forest, and transects across the peninsula between Lakes Michigan and Huron to study particle formation, transport, and deposition. Preliminary results reveal a well-mixed troposphere above the forest with a mode ~0.1 μm, while in several cases, the total particle concentration over Lake Michigan is an order of magnitude greater than over the forest. There is a consistent bimodal distribution of particle sizes over Lake Michigan the lowest of which is centered at ~0.025 μm, suggesting the possibility of new particle formation. This mode is consistent with the presence of breaking waves on the lake’s surface, and this mode and the vertical structure depend greatly on wind speed. We present here evidence for new particle production from breaking waves on fresh water lakes, and discuss the results

  11. David Morrison on Lake Vostok

    NASA Video Gallery

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

  12. 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.

  13. Subglacial lake drainage detected beneath the Greenland ice sheet

    PubMed Central

    Palmer, Steven; McMillan, Malcolm; Morlighem, Mathieu

    2015-01-01

    The contribution of the Greenland ice sheet to sea-level rise has accelerated in recent decades. Subglacial lake drainage events can induce an ice sheet dynamic response—a process that has been observed in Antarctica, but not yet in Greenland, where the presence of subglacial lakes has only recently been discovered. Here we investigate the water flow paths from a subglacial lake, which drained beneath the Greenland ice sheet in 2011. Our observations suggest that the lake was fed by surface meltwater flowing down a nearby moulin, and that the draining water reached the ice margin via a subglacial tunnel. Interferometric synthetic aperture radar-derived measurements of ice surface motion acquired in 1995 suggest that a similar event may have occurred 16 years earlier, and we propose that, as the climate warms, increasing volumes of surface meltwater routed to the bed will cause such events to become more common in the future. PMID:26450175

  14. Subglacial lake drainage detected beneath the Greenland ice sheet.

    PubMed

    Palmer, Steven; McMillan, Malcolm; Morlighem, Mathieu

    2015-10-09

    The contribution of the Greenland ice sheet to sea-level rise has accelerated in recent decades. Subglacial lake drainage events can induce an ice sheet dynamic response--a process that has been observed in Antarctica, but not yet in Greenland, where the presence of subglacial lakes has only recently been discovered. Here we investigate the water flow paths from a subglacial lake, which drained beneath the Greenland ice sheet in 2011. Our observations suggest that the lake was fed by surface meltwater flowing down a nearby moulin, and that the draining water reached the ice margin via a subglacial tunnel. Interferometric synthetic aperture radar-derived measurements of ice surface motion acquired in 1995 suggest that a similar event may have occurred 16 years earlier, and we propose that, as the climate warms, increasing volumes of surface meltwater routed to the bed will cause such events to become more common in the future.

  15. The origin of shallow lakes in the Khorezm Province, Uzbekistan, and the history of pesticide use around these lakes

    USGS Publications Warehouse

    Rosen, Michael R.; Crootof, Arica; Reidy, Liam; Saito, Laurel; Nishonov, Bakhriddin; Scott, Julian A.

    2016-01-01

    The economy of the Khorezm Province in Uzbekistan relies on the large-scale agricultural production of cotton. To sustain their staple crop, water from the Amu Darya is diverted for irrigation through canal systems constructed during the early to mid-twentieth century when this region was part of the Soviet Union. These diversions severely reduce river flow to the Aral Sea. The Province has >400 small shallow (<3 m deep) lakes that may have originated because of this intensive irrigation. Sediment cores were collected from 12 lakes to elucidate their origin because this knowledge is critical to understanding water use in Khorezm. Core chronological data indicate that the majority of the lakes investigated are less than 150 years old, which supports a recent origin of the lakes. The thickness of lacustrine sediments in the cores analyzed ranged from 20 to 60 cm in all but two of the lakes, indicating a relatively slow sedimentation rate and a relatively short-term history for the lakes. Hydrologic changes in the lakes are evident from loss on ignition and pollen analyses of a subset of the lake cores. The data indicate that the lakes have transitioned from a dry, saline, arid landscape during pre-lake conditions (low organic carbon content) and low pollen concentrations (in the basal sediments) to the current freshwater lakes (high organic content), with abundant freshwater pollen taxa over the last 50–70 years. Sediments at the base of the cores contain pollen taxa dominated by Chenopodiaceae and Tamarix, indicating that the vegetation growing nearby was tolerant to arid saline conditions. The near surface sediments of the cores are dominated by Typha/Sparganium, which indicate freshwater conditions. Increases in pollen of weeds and crop plants indicate an intensification of agricultural activities since the 1950s in the watersheds of the lakes analyzed. Pesticide profiles of DDT (dichlorodiphenyltrichloroethane) and its degradates and γ-HCH (gamma

  16. Surface ozone in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Burley, Joel D.; Theiss, Sandra; Bytnerowicz, Andrzej; Gertler, Alan; Schilling, Susan; Zielinska, Barbara

    2015-05-01

    pollution source regions. Calculation of ozone exposure indices indicates that the two most polluted sites sampled by active monitors in 2010 - the highest Genoa Peak site, located on the eastern side of the Lake at an elevation of 2734 m above sea level, and Angora Lookout, located to the south-southwest (SSW) of the Lake at an elevation of 2218 m above sea level - likely experienced some phytotoxic impacts, while the other Tahoe Basin locations received lower ozone exposures.

  17. Great Lakes Literacy Principles

    NASA Astrophysics Data System (ADS)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

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

  18. 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.

  19. Bacterial voltage-gated sodium channels (BacNaVs) from the soil, sea, and salt lakes enlighten molecular mechanisms of electrical signaling and pharmacology in the brain and heart

    PubMed Central

    Payandeh, Jian; Minor, Daniel L.

    2014-01-01

    Voltage-gated sodium channels (NaVs) provide the initial electrical signal that drives action potential generation in many excitable cells of the brain, heart, and nervous system. For more than 60 years, functional studies of NaVs have occupied a central place in physiological and biophysical investigation of the molecular basis of excitability. Recently, structural studies of members of a large family of bacterial voltage-gated sodium channels (BacNaVs) prevalent in soil, marine, and salt lake environments that bear many of the core features of eukaryotic NaVs have reframed ideas for voltage-gated channel function, ion selectivity, and pharmacology. Here, we analyze the recent advances, unanswered questions, and potential of BacNaVs as templates for drug development efforts. PMID:25158094

  20. Role of physical barriers in the control of sea lamprey (Petromyzon marinus)

    USGS Publications Warehouse

    Hunn, J.B.; Youngs, W.D.

    1980-01-01

    Mechanical and electromechanical barriers played a significant role in the initial attempts to control sea lamprey (Petromyzon marinus) populations in the upper Great Lakes. More recently electromechanical weirs have been used to assess the relative abundance of spawning-run sea lampreys in Lake Superior. Development of an integrated control approach to sea lamprey control has stimulated an ongoing research program to define structural and/or velocity criteria that can be used to design barrier dams that block spawning runs of sea lamprey

  1. 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.

  2. 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.

  3. Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this Moderate-resolution Imaging Spectroradiometer (MODIS) image from December 3, 2001, winter sea ice can be seen forming in the shallow waters of the northern Caspian (left) and Aral (upper right) Seas. Despite the inflow of the Volga River (upper left), the northern portion of the Caspian Sea averages only 17 feet in depth, and responds to the region's continental climate, which is cold in winter and hot and dry in the summer. The southern part of the Sea is deeper and remains ice-free throughout the winter. The dirty appearance of the ice may be due to sediment in the water, but may also be due to wind-driven dust. The wind in the region can blow at hurricane-force strength and can cause the ice to pile up in hummocks that are anchored to the sea bottom. The eastern portion of the Aral Sea is also beginning to freeze. At least two characteristics of the Aral Sea 'compete' in determining whether its waters will freeze. The Sea is shallow, which increases the likelihood of freezing, but it is also very salty, which means that lower temperatures are required to freeze it than would be required for fresh water. With average December temperatures of 18oF, it's clearly cold enough to allow ice to form. As the waters that feed the Aral Sea continue to be diverted for agriculture, the Sea becomes shallower and the regional climate becomes even more continental. This is because large bodies of water absorb and retain heat, moderating seasonal changes in temperature. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  4. 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

  5. Returns of hatchery-reared lake trout in southern Lake Superior, 1955-62

    USGS Publications Warehouse

    Pycha, Richard L.; King, George R.

    1967-01-01

    Experimental plantings of fin-clipped lake trout (Salvelinus namaycush) of various ages have been made in southern Lake Superior since 1952. The catch of planted lake trout by the commercial fishery was used to measure the success of stocking. Estimates of total returns were based on samples of 8.2 to 21.2% of the Wisconsin catches in 1955-62 and 36.4 to 46.8% of the Michigan catches in 1959-62. Marked lake trout were assigned to various plantings according to the fin mark, length of fish, readings of age from scales, and locations of capture. Estimated returns from Wisconsin plantings of 9-month-old lake trout varied from 2.1 to 6.4%. Wisconsin releases of 16-month-old fish yielded returns of 5.7 to 37.3%. Returns from plantings in Michigan were 0.3% for 9-month-old fish and 1.5 to 3.8% for 16-month-old fish. The ratios of the returns from plantings of 16-month-old fish to those of 9-month-old fish were 3.9:1 for Wisconsin releases and 6.7:1 for Michigan releases. Lake trout planted in Wisconsin generally survived better than those released in Michigan. Returns from fish planted at ages of 17 to 40 months in Michigan in 1958-59 were far greater than those from 16-month-old fish released in Michigan, but were not as high as from the most successful plantings of 16-month-old fish in Wisconsin. Lake trout released in 1960 from shore and from boats survived equally well. Average size of lake trout at release was more closely related to survival than any other factor. All except 1 of 10 highly successful releases were of fish larger than 22 per lb, and all 6 poor releases were of fish smaller than 34 per lb. Fish that ran 22 to 33 per lb survived only moderately well. A size of 17 to 20 fish per lb appears to be close to optimum. Abundance of native lake trout, American smelt (Osmerus mordax), and sea lampreys (Petromyzon marinus) all appeared to be unrelated to stocking success. The only apparent method of rapidly improving the success of stocking is to rear all lake

  6. The influence of subsurface flow on lake formation and north polar lake distribution on Titan

    NASA Astrophysics Data System (ADS)

    Horvath, David G.; Andrews-Hanna, Jeffrey C.; Newman, Claire E.; Mitchell, Karl L.; Stiles, Bryan W.

    2016-10-01

    Observations of lakes, fluvial dissection of the surface, rapid variations in cloud cover, and lake shoreline changes indicate that Saturn's moon Titan is hydrologically active, with a hydrocarbon-based hydrological cycle dominated by liquid methane. Here we use a numerical model to investigate the Titan hydrological cycle - including surface, subsurface, and atmospheric components - in order to investigate the underlying causes of the observed distribution and sizes of lakes in the north polar region. The hydrocarbon-based hydrological cycle is modeled using a numerical subsurface flow model and analytical runoff scheme, driven by a general circulation model with an active methane-cycle. This model is run on synthetically generated topography that matches the fractal character of the observed topography, without explicit representation of the effects of erosion and deposition. At the scale of individual basins, intermediate to high permeability (10-8-10-6 cm2) aquifers are required to reproduce the observed large stable lakes. However, at the scale of the entire north polar lake district, a high permeability aquifer results in the rapid flushing of methane through the aquifer from high polar latitudes to dry lower polar latitudes, where methane is removed by evaporation, preventing large lakes from forming. In contrast, an intermediate permeability aquifer slows the subsurface flow from high polar latitudes, allowing greater lake areas. The observed distribution of lakes is best matched by either a uniform intermediate permeability aquifer, or a combination of a high permeability cap at high latitudes surrounded by an intermediate permeability aquifer at lower latitudes, as could arise due to karstic processes at the north pole. The stability of Kraken Mare further requires reduction of the evaporation rate over the sea to 1% of the value predicted by the general circulation model, likely as a result of dissolved ethane, nitrogen, or organic solutes, and/or a

  7. Artificial propagation of the sea lamprey Petromyzon marinus

    USGS Publications Warehouse

    Lennon, Robert E.

    1955-01-01

    Observations on the gland products, gonads, and general characteristics of sexually mature sea lampreys, Petromyzon marinus (Linnaeus), from Lake Huron, and a need to obtain some information on very young larval lampreys, prompted an experiment on the stripping and hatching of eggs. Seventeen specimens were selected from a group of spawning migrants which had been trapped in the Ocqueoc River, Michigan, during June and held in live-cars in the lake until early August.

  8. The lakes of Titan

    USGS Publications Warehouse

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

    2007-01-01

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

  9. Great Salt Lake, Utah

    USGS Publications Warehouse

    Stephens, Doyle W.; Gardner, Joe F.

    1999-01-01

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

  10. Great Lakes Teacher's Guide.

    ERIC Educational Resources Information Center

    Reid, Ron

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

  11. The lakes of Titan.

    PubMed

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

    2007-01-04

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

  12. 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)

  13. 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…

  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)…

  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. Evaporation From Lake Superior

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

  17. ANALYSES OF ORGANIC AND INORGANIC CONTAMINANTS IN SALTON SEA FISH. (R826552)

    EPA Science Inventory

    Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthul...

  18. Introduction and summary: Chlorinated hydrocarbons as a factor in the reproduction and survival of lake trout (Salvelinus namaycush) in Lake Michigan

    USGS Publications Warehouse

    Willford, Wayne A.; Bergstedt, Roger A.; Berlin, William H.; Foster, Neal R.; Hesselberg, Robert J.; Mac, Michael J.; Passino, Dora R. May; Reinert, Robert E.; Rottiers, Donald V.

    1981-01-01

    Although lake trout (Salvelinus namaycush) were considered extinct in Lake Michigan by the mid 1950's, control of the parasitic sea lamprey (Petromyzon marinus) and extensive restocking resulted in an abundance of hatchery-produced lake trout in the lake by the early 1970's. However, no naturally produced yearling or older lake trout have been found in the lake during nearly a decade of assessment sampling. Among the numerous hypotheses proposed to account for this apparent reproductive failure of the planted lake trout, a frequently suggested cause is the well-documented contamination of the fish by toxic substances such as DDT and its metabolites, and polychlorinated biphenyls (PCB's) at concentrations reported as adversely affecting the hatching of eggs and survival of larval fish. However, manually stripped and fertilized eggs of Lake Michigan lake trout have hatched successfully and the fry have survived normally under a variety of hatchery conditions. This observation led to studies at the Great Lakes Fishery Laboratory on the performance and survival of fry hatched from eggs of Lake Michigan lake trout and exposed for 6 months to PCB's (Aroclor 1254) and DDE at concentrations similar to those present in offshore waters and zooplankton of Lake Michigan (10.0 ng/L PCB's and 1.0 ng/L DDE in water; 1.0 μg/g PCB's and 0.1 μg/g DDE in food), and at concentrations 5 and 25 times higher. Cumulative mortality of the fry exposed to simulated Lake Michigan levels of PCB's and DDE for 6 months was 40.7% — nearly twice that of unexposed (control) fry — and mortality at the highest exposure level was 46.5%. Evaluation of the growth, swimming performance, predator avoidance, temperature preference, and metabolism of the fry showed no significant effects attributable to exposure to PCB's and DDE, except for a lowering of preferred temperature at the highest (25x) exposures (the only concentration tested) to each contaminant and (additively) both contaminants combined

  19. Resistance to 3-trifluoromethyl-4-nitrophenol (TFM) in sea lamprey

    USGS Publications Warehouse

    Scholefield, R.J.; Seelye, J.G.

    1990-01-01

    The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) has been used in the United States and Canada for more than 30 years to control populations of sea lamprey (Petromyzon marinus) in the Great Lakes. There is concern that sea lamprey might become resistant to TFM. Lampricide toxicity tests have been conducted at the Hammond Bay Biological Station, Millersburg, Michigan, since the 1950s and examination of TFM toxicity data for larval lamprey from 1963 to 1987 indicated that sea lamprey have not developed increased resistance to TFM. Maintenance of current control practices are unlikely to cause the development of TFM-resistant sea lamprey strains in the foreseeable future.

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

    USGS Publications Warehouse

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

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

    USGS Publications Warehouse

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

    1988-01-01

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

  2. Optical properties of the Dead Sea

    NASA Astrophysics Data System (ADS)

    Boss, Emmanuel; Gildor, Hezi; Slade, Wayne; Sokoletsky, Leonid; Oren, Aharon; Loftin, James

    2013-04-01

    The Dead Sea, located in the rift valley between Jordan and Israel, is a hypersaline lake, 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 on the optical properties of water, our analysis required a novel processing approach to obtain dissolved and total inherent optical properties from the measurements. In addition, we show that the lake's salinity can be estimated from measurements of hyper-spectral absorption or attenuation spectra in the red and infrared parts of the spectrum, using published values of specific absorption of dissolved NaCl, despite the fact that the lake's salt chemistry is complex. In situ observations demonstrated that the lake has a two-layer structure with a warm and more turbid layer at the top 20-30 m and a clearer colder layer below. Both the particulate and dissolved absorption are well approximated by exponentially decreasing functions with the spectral slope of the particulate absorption about half that of the dissolved fraction and consistent with other aquatic environments. Both have relatively low and similar magnitudes in the blue (O(0.15 m-1)). Mean particle size was observed to increase with depth, consistent with precipitating salt crystals (observed in past campaigns) shown here to play a major role in the lake's optical properties.

  3. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

    DeSorcie, Timothy J.; Bowen, Charles A.

    2003-01-01

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

  4. 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.

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

    DTIC Science & Technology

    1991-10-01

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

  6. Arabian Sea

    Atmospheric Science Data Center

    2013-04-16

    ... sometimes results in copious phytoplankton production and oxygen depletion of the subsurface waters. Although red phytoplankton fluorescences have been associated with the low oxygen concentrations in the intermediate and deep waters of the Arabian Sea, ...

  7. Geochronology and Stratigraphy of Pluvial Argentinean Lakes: Implications for Quaternary Climate Change

    NASA Astrophysics Data System (ADS)

    Cartwright, A.

    2009-12-01

    Shoreline deposits of pluvial lake systems can provide direct evidence of the timing and duration of lake high stands. Complemented by careful stratigraphic and geochemical analysis, these records also contain important paleoenvironmental information. Two lake systems were studied as part of a global effort to understand major climatic changes during the Last Glacial Maximum (LGM: 24-18 ka) and the following deglaciation (18-13 ka). Today, both of the studied regions are arid, and the lake basins contain much smaller lakes than in the past. Laguna Cari-Laufquen is located at 41°S and the modern basin is occupied by two lakes: Cari-Laufquen Grande and Chica. Preserved shorelines and sediments show these two lakes rose and merged multiple times during the Late Quaternary. An extensive radiocarbon geochronology show the lake was the highest during the LGM, with several smaller, more recent lake oscillations in the last thousand years. The second lake system in this study is Laguna Bebedero, located at 33°S in western Argentina. Previous studies show the highest shorelines date to 23-16,000 yrs BP. Our new radiocarbon dates help constrain the timing of the highstands - and show highstands during the deglacial period. Our lake highstand evidence provides a unique opportunity to reconstruct shifts in Atlantic (easterly)- or Pacific (westerly)-driven moisture. Geochemical studies of shell, water chemical analysis, and geospatial analysis also help to constrain hydrologic balance and paleoenvironmental conditions. Comparison of paleohydrologic records in South America. From top: Cariaco Basin - reconstructed sea-surface temperatures from Lea et al., 2003, Bolivian Lakes - Uyuni lake system phases from shoreline data (Placzek et al., 2006), Atacama Wetlands - wet events above local water table (Quade et al., 2008), Laguna Bebedero and Laguna Cari-Laufquen - lake level changes from this study.

  8. Wind-driven Water Bodies : a new paradigm for lake geology

    NASA Astrophysics Data System (ADS)

    Nutz, A.; Schuster, M.; Ghienne, J. F.; Roquin, C.; Bouchette, F. A.

    2015-12-01

    In this contribution we emphasize the importance in some lakes of wind-related hydrodynamic processes (fair weather waves, storm waves, and longshore, cross-shore and bottom currents) as a first order forcing for clastics remobilization and basin infill. This alternative view contrasts with more classical depositional models for lakes where fluvial-driven sedimentation and settling dominates. Here we consider three large lakes/paleo-lakes that are located in different climatic and geodynamic settings: Megalake Chad (north-central Africa), Lake Saint-Jean (Québec, Canada), and Lake Turkana (Kenya, East African Rift System). All of these three lake systems exhibit well developed modern and ancient high-energy littoral morphosedimentary structures which directly derive from wind-related hydrodynamics. The extensive paleo-shorelines of Megalake Chad are composed of beach-foredune ridges, spits, wave-dominated deltas, barriers, and wave-ravinment surface. For Lake Saint-Jean the influence of wind is also identified below the wave-base at lake bottom from erosional surfaces, and sediment drifts. In the Lake Turkana Basin, littoral landforms and deposits are identified for three different time intervals (today, Holocene, Plio-Pleistocene) evidencing that wind-driven hydrodynamics can be preserved in the geological record. Moreover, a preliminary global survey suggests that numerous modern lakes (remote sensing) and paleo-lakes (bibliographic review) behave as such. We thus coin the term "Wind-driven Water Bodies" (WWB) to refer to those lake systems where sedimentation (erosion, transport, deposition) is dominated by wind-induced hydrodynamics at any depth, as it is the case in the marine realm for shallow seas. Integrating wind forcing in lake models has strong implications for basin analysis (paleoenvironments and paleoclimates restitutions, resources exploration), but also for coastal engineering, wildlife and reservoirs management, or leisure activities.

  9. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  10. Impacts of aquatic nonindigenous invasive species on the Lake Erie ecosystem

    USGS Publications Warehouse

    Austen, Madeline J.W.; Ciborowski, Jan J.H.; Corkum, Lynda D.; Johnson, Tim B.; MacIsaac, Hugh J.; Metcalfe-Smith, Janice L.; Schloesser, Donald W.; George, Sandra E.

    2002-01-01

    Lake Erie is particularly vulnerable to the introduction and establishment of aquatic nonindigenous invasive species (NIS) populations. A minimum of 144 aquatic NIS have been recorded in the Lake Erie basin including several species [e.g., Eurasian watermilfoil (Myriophyllum spicatum); zebra mussel (Dreissena polymorpha); quagga mussel (Dreissena bugensis); an amphipod (Echinogammarus ischnus); round goby (Neogobius melanostomus); and sea lamprey (Petromyzon marinus)] that have had discernible impacts on the lake's ecology. NIS pose threats to the Lake Erie ecosystem for a variety of reasons including their ability to proliferate quickly, compete with native species, and transfer contaminants (e.g., PCBs) and disease through the food web. Six of the 14 beneficial use impairments listed in Annex 2 of the Great Lakes Water Quality Agreement are impaired in Lake Erie, in part as a result of the introduction of NIS. The Lake Erie Lakewide Management Plan (LaMP) has adopted an ecosystem approach to restore beneficial use impairments in the lake. Furthermore, a research consortium, known as the Lake Erie Millennium Network, is working alongside the LaMP, to address research problems regarding NIS, the loss of habitat, and the role of contaminants in the Lake Erie ecosystem.

  11. 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.

  12. 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.

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

    USGS Publications Warehouse

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

    2006-01-01

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

  14. Telemetry narrows the search for sea lamprey spawning locations in the St. Clair-Detroit River System

    USGS Publications Warehouse

    Holbrook, Christopher; Jubar, Aaron K.; Barber, Jessica M.; Tallon, Kevin; Hondorp, Darryl W.

    2016-01-01

    Adult sea lamprey (Petromyzon marinus) abundance in Lake Erie has remained above targets set by fishery managers since 2005, possibly due to increased recruitment in the St. Clair-Detroit River System (SCDRS). Sea lamprey recruitment in the SCDRS poses an enormous challenge to sea lamprey control and assessment in Lake Erie because the SCDRS contains no dams to facilitate capture and discharge is at least an order of magnitude larger in the SCDRS than most other sea lamprey-producing tributaries in the Great Lakes. As a first step toward understanding population size, spatial distribution, and spawning habitat of adult sea lampreys in the SCDRS, we used acoustic telemetry to determine where sea lampreys ceased migration (due to spawning, death, or both) among major regions of the SCDRS. All tagged sea lampreys released in the lower Detroit River (N = 27) moved upstream through the Detroit River and entered Lake St. Clair. After entering Lake St. Clair, sea lampreys entered the St. Clair River (N = 22), Thames River (N = 1), or were not detected again (N = 4). Many sea lampreys (10 of 27) were last observed moving downstream (“fallback”) but we were unable to determine if those movements occurred before or after spawning, or while sea lampreys were dead or alive. Regardless of whether estimates of locations where sea lampreys ceased migration were based on the most upstream region occupied or final region occupied, most sea lampreys ceased migration in the St. Clair River or Lake St. Clair. Results suggest that spawning and rearing in the St. Clair River could be an important determinant of sea lamprey recruitment in the SCDRS and may direct future assessment and control activities in that system.

  15. Marine Incursion: The Freshwater Herring of Lake Tanganyika Are the Product of a Marine Invasion into West Africa

    PubMed Central

    Wilson, Anthony B.; Teugels, Guy G.; Meyer, Axel

    2008-01-01

    The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25–50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics. PMID:18431469

  16. Ecology under lake ice.

    PubMed

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

    2017-01-01

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

  17. Yellowstone lake nanoarchaeota.

    PubMed

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

    2013-01-01

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

  18. Ecology of playa lakes

    USGS Publications Warehouse

    Haukos, David A.; Smith, Loren M.

    1992-01-01

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

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

    SciTech Connect

    Tilson, Mary Beth; Underwood, Keith D.; Shields, John

    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.

  20. The Great Salt Lake

    USGS Publications Warehouse

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

    1991-01-01

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

  1. National Lakes Assessment Data

    EPA Pesticide Factsheets

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

  2. Aral Sea and sustainable development.

    PubMed

    Usmanova, R M

    2003-01-01

    Until 1960 the Aral Sea was considered the 4th largest lake in the world by surface area. The Aral Sea has two main inflows--the Amudarya and Syrdarya rivers with about 30 tributaries. From early 1960s because of extensive water use--unreturned withdrawal of water for irrigation and consequent drying up of many tributaries before reaching the main rivers--the water level in the Aral Sea began falling very rapidly. In 1965 the Aral Sea received about 56 cubic km of fresh water yearly, but this number fell to zero by the early 1980s. By 1990 the level of the Aral Sea water fell by more than 17 m, the volume of water decreased by 75%, the salinity of seawater increased up to 30 g/l, and the surface area of the sea reduced from 66,400 sq. km to 31,500 sq. km. The ecological situation in Aral Sea zone has became very dramatic. It has led to the changing of climate in the region, irrigated soils becoming deserts, deterioration of underground and surface water quality, reducing of available water for domestic and agricultural needs, loss of Aral Sea fishing and transportation importance, numerous other problems and finally put the health of present and future generations under threat. This situation not only does not promote further development of the economy of the region, but has also caused damage with irreparable negative consequences. The fact is that the basis of the regional economy is fishing and other associated businesses. Since Uzbekistan is most agricultural country its economy has serious complications. In order to prevent further deepening of this catastrophe and to improve the present situation in this area the Government of the Republic of Uzbekistan has developed a series of measures: in particular it developed efficient water use schemes, changing the cotton situation (that during the Soviet period was grown as monoculture) by planting less water-consuming varieties, reviewing using of fertilizers in agriculture etc. The Aral Sea drought became an

  3. Cyanide Soap? Dissolved material in Titan's Seas

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.; Lunine, J. I.; Neish, C. D.

    2011-10-01

    Although it is evident that Titan's lakes and seas are dominated by ethane, methane, nitrogen, and (in some models) propane, there is divergence on the predicted relative abundance of minor constituents such as nitriles and C-4 alkanes. Nitriles such as hydrogen cyanide and acetonitrile, which have a significant dipole moment, may have a disproportionate influence on the dielectric properties of Titan seas and may act to solvate polar molecules such as water ice. The hypothesis is offered that such salvation may act to enhance the otherwise negligible solubility of water ice bedrock in liquid hydrocarbons. Such enhanced solubility may permit solution erosion as a formation mechanism for the widespread pits and apparently karstic lakes on Titan. Prospects for testing this hypothesis in the laboratory, and with measurements on Titan, will be discussed.

  4. Federal Great Lakes fishery research objectives, priorities, and projects

    USGS Publications Warehouse

    Tait, Howard D.

    1973-01-01

    Fishery productivity of the Great Lakes has declined drastically since settlement of the area. Premium quality fishes of the Great Lakes such as whitefish, lake trout, and walleyes have been replaced by less desired species. This change is attributed to selective overfishing, pollution, and the extreme instability of fish populations. Sea lamprey predation is still a vexing problem but progress is being made in controlling this parasite. The federal fishery research program with headquarters in Ann Arbor, Michigan, has the objective of providing baseline information, needed in resource use decisions, about the fishes of the Great Lakes. Studies of the habitat requirements of fish are high priority. The program includes fish population assessments, studies of the effects of mercury and other contaminants on fish, thermal effects studies, and general investigation of the impact of engineering projects on Great Lakes fisheries. The work is closely coordinated with state and Canadian agencies through the Great Lakes Fishery Commission. Four small research vessels and four field stations are utilized with a staff of 90 and an annual budget of about $1.5 million.

  5. 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.

  6. Influence of the Laurentian Great Lakes on Regional Climate

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  7. 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 offish 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 rnid-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

  8. Challenges to the Lake

    EPA Science Inventory

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

  9. About Deer Lake AOC

    EPA Pesticide Factsheets

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

  10. 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

  11. Stratification of lakes

    NASA Astrophysics Data System (ADS)

    Boehrer, Bertram; Schultze, Martin

    2008-06-01

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

  12. Sea-Spike Detection in High Grazing Angle X-band Sea-Clutter

    DTIC Science & Technology

    2012-04-01

    and verification, Journal of Geophysical Research 96(C11), 20,547– 20,559. Keller, M . R., Gotwols, B. L . & Chapman, R. D. (2002) Multiple sea spike...Hindman, C. L ., Lake, B. M ., Rungaldier, H., Shelton, J. C., Williams, A. B., Yee, R. & Yuen, H. C. (1995a) X-band microwave backscattering from...ocean waves, Journal of Geophysical Research 100(C2), 2591–2611. Lee, P. H. Y., Barter, J. D., Caponi, E., Hidman, C. L ., Lake, B. M ., Rungaldier, H

  13. 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

  14. Declining survival of lake trout stocked during 1963-1986 in U.S. waters of Lake Superior

    USGS Publications Warehouse

    Hansen, Michael J.; Ebener, Mark P.; Schorfhaar, Richard G.; Schram, Stephen T.; Schreiner, Donald R.; Selgeby, James H.

    1994-01-01

    The average catch per effort (CPE) values for the 1963–1982 year-classes of stocked lake trout Salvelinus namaycush caught at age 7 in gill nets and for the 1976–1986 year-classes caught at ages 2–4 in trawls declined significantly in U.S. waters of Lake Superior. The declines in CPE were not explained by reduced stocking, but rather by significant declines in survival indices of the year-classes of stocked lake trout. Increases in mortality occurred in year-classes before the fish reached ages 2–4, before they were recruited into the sport and commercial fisheries, and before they reached sizes vulnerable to sea lamprey predation. We conclude that declining abundance of stocked lake trout resulted from increased mortality, which may have been caused by competition, predation, or by a combination of these and other factors. Restoration of lake trout in Lake Superior may now depend on prudent management of naturally reproducing stocks rather than on stocking of hatchery-reared fish.

  15. Lake Chad, Chad, Africa

    NASA Technical Reports Server (NTRS)

    1988-01-01

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

  16. Antarctic subglacial lake discharges

    NASA Astrophysics Data System (ADS)

    Pattyn, Frank

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

  17. Dragon Lake, Siberia

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  18. Lake retention of manufactured nanoparticles.

    PubMed

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

    2015-01-01

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

  19. Schistosomiasis in Lake Malawi.

    PubMed

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

    1996-11-09

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

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

    DTIC Science & Technology

    1991-08-01

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

  1. Is Lake Chabot Eutrophic?

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  2. 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.

  3. 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.

  4. Boll weevil eradication: a model for sea lamprey control?

    USGS Publications Warehouse

    Smith, James W.; Swink, William D.

    2003-01-01

    Invasions of boll weevil (Anthonomus grandis) into the United States and sea lamprey (Petromyzon marinus) into the Great Lakes were similar in many ways. Important species (American cotton, Gossypium hirsutum, and lake trout, Salvelinus namaycush) and the industries they supported were negatively affected. Initial control efforts were unsuccessful until pesticides and application technologies were developed. For boll weevils, controls relying on pesticides evolved into an integrated program that included recommended farming practices and poisoned baits. However, the discovery of a boll weevil sex pheromone in 1964 allowed adoption of an ongoing program of eradication. Despite opposition over concept and cost, insecticides, pheromone traps, poisoned baits, and approved farming practices were used to eradicate boll weevils from Virginia, North Carolina, South Carolina, Georgia, Florida, and Alabama by 1999. Using the working back approach along the path of the original invasion, eradication was nearly completed by 2002 in Mississippi and eradication programs were underway in Arkansas, Tennessee, Oklahoma, Louisiana, and parts of Texas. Insecticide use for cotton production decreased 50 to 90%, and cotton yields and farm income increased an average of 78 kg/ha and $190 U.S./ha in areas where boll weevils were eradicated. For sea lampreys, integrated management uses lampricides, barriers to migration, trapping, and release of sterilized males. Although sea lamprey eradication is not currently feasible, recent research on larval and sex pheromones might provide the tools to make it possible. A successful eradication program for sea lampreys starting in Lake Superior and expanding to the lower Great Lakes would ultimately provide huge ecological and economic benefits by eliminating lampricide applications, removing barriers that block teleost fishes, and facilitating the recovery of lake trout. Should the opportunity arise, the concept of sea lamprey eradication should

  5. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    EPA Science Inventory

    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  6. Glacial lake inventory and lake outburst potential in Uzbekistan.

    PubMed

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

    2017-03-16

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

  7. Comparative bioenergetics modeling of two Lake Trout morphotypes

    USGS Publications Warehouse

    Kepler, Megan V.; Wagner, Tyler; Sweka, John A.

    2014-01-01

    Efforts to restore Lake Trout Salvelinus namaycush in the Laurentian Great Lakes have been hampered for decades by several factors, including overfishing and invasive species (e.g., parasitism by Sea Lampreys Petromyzon marinus and reproductive deficiencies associated with consumption of Alewives Alosa pseudoharengus). Restoration efforts are complicated by the presence of multiple body forms (i.e., morphotypes) of Lake Trout that differ in habitat utilization, prey consumption, lipid storage, and spawning preferences. Bioenergetics models constitute one tool that is used to help inform management and restoration decisions; however, bioenergetic differences among morphotypes have not been evaluated. The goal of this research was to investigate bioenergetic differences between two actively stocked morphotypes: lean and humper Lake Trout. We measured consumption and respiration rates across a wide range of temperatures (4–22°C) and size-classes (5–100 g) to develop bioenergetics models for juvenile Lake Trout. Bayesian estimation was used so that uncertainty could be propagated through final growth predictions. Differences between morphotypes were minimal, but when present, the differences were temperature and weight dependent. Basal respiration did not differ between morphotypes at any temperature or size-class. When growth and consumption differed between morphotypes, the differences were not consistent across the size ranges tested. Management scenarios utilizing the temperatures presently found in the Great Lakes (e.g., predicted growth at an average temperature of 11.7°C and 14.4°C during a 30-d period) demonstrated no difference in growth between the two morphotypes. Due to a lack of consistent differences between lean and humper Lake Trout, we developed a model that combined data from both morphotypes. The combined model yielded results similar to those of the morphotype-specific models, suggesting that accounting for morphotype differences may

  8. First Year Results from the Circumarctic Lakes Observation Network (CALON) Project

    NASA Astrophysics Data System (ADS)

    Hinkel, K. M.; Arp, C. D.; Frey, K. E.; Lenters, J. D.; Beck, R. A.; Eisner, W. R.; Gaglioti, B.; Grosse, G.; Jones, B. M.; Kim, C.; Liu, H.; Townsend-Small, A.

    2012-12-01

    In April 2012, instruments were deployed in over 50 lakes in northern Alaska as the initial phase of CALON, a project designed to observe short- and long-term variability in physical, limnological and biogeochemical processes in Arctic lakes. The network currently consists of nine observation nodes on two parallel transects extending from the Arctic Ocean south to the Brooks Range Foothills. At each node, at least six representative lakes that vary by surface area and depth were instrumented at different intensity levels: basic, enhanced and comprehensive. At each node we deployed a suite of instrumentation and collected a variety of field measurements. This approach allows for the study of lakes and their diversity across strong physical and biological gradients. To date we have established sites at a wide variety of Arctic lake types; 25 are thermokarst lakes set in ice-rich, fine-grained marine surficial sediments (Outer Coastal Plain), 6 lakes are in alluvial/aeolian sediments (Inner Coastal Plain) and 6 are in ice-rich silt (Arctic Foothills Yedoma), 5 are depressional lakes formed in a late Pleistocene sand sheet (Ikpikpuk Sand Sea), 6 represent glacial thermokarst or kettle lakes near the Brooks Range (Toolik region), 7 lakes are of fluvial or deltaic origin (Fish Creek basin, Ikpikpuk Delta), and Teshekpuk Lake, the largest lake in Arctic Alaska, is of a complex origin. In April, sensors measuring water temperature and water depth were deployed through the ice cover, water samples were collected, and real-time time lapse cameras were installed to capture snow melt and ice-off. Sensors were recovered from lakes and meteorological stations in August, recording lake regimes and events from ice decay and snowmelt influx to open-water warming and water balance. In general, lake ice thickness increased with latitude; in lakes deeper than 2 m, ice was about 1.4 m thick in the Arctic Foothills and 1.7 m thick near the coast of the Arctic Ocean with inter-lake

  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, Michael L.

    1991-01-01

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

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

    USGS Publications Warehouse

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

    2007-01-01

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

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

    USGS Publications Warehouse

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

    2006-01-01

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

  12. Do invasive quagga mussels alter CO2 dynamics in the Laurentian Great Lakes?

    PubMed Central

    Lin, Peng; Guo, Laodong

    2016-01-01

    The Laurentian Great Lakes have experienced unprecedented ecological and environmental changes, especially after the introduction of invasive quagga mussel (Dreissena rostriformis bugensis). While impacts on ecological functions have been widely recognized, the response of carbon dynamics to invasive species remains largely unknown. We report new CO2 data showing significant increases in pCO2 (up to 800 μatm in Lake Michigan) and CO2 emission fluxes in most of the Great Lakes compared to those prior to or during the early stage of the colonization of invasive quagga mussels. The increased CO2 supersaturation is most prominent in Lakes Huron and Michigan, followed by Lakes Ontario and Erie, but no evident change was observed in Lake Superior. This trend mirrors the infestation extent of invasive quagga mussels in the Great Lakes and is consistent with the decline in primary production and increase in water clarity observed pre- and post-Dreissena introduction, revealing a close linkage between invasive species and carbon dynamics. The Great Lakes have become a significant CO2 source to the atmosphere, emitting >7.7 ± 1.0 Tg-C annually, which is higher than the organic carbon burial rate in global inland-seas and attesting to the significant role of the Laurentian Great Lakes in regional/global CO2 budget and cycling. PMID:27996017

  13. Do invasive quagga mussels alter CO2 dynamics in the Laurentian Great Lakes?

    NASA Astrophysics Data System (ADS)

    Lin, Peng; Guo, Laodong

    2016-12-01

    The Laurentian Great Lakes have experienced unprecedented ecological and environmental changes, especially after the introduction of invasive quagga mussel (Dreissena rostriformis bugensis). While impacts on ecological functions have been widely recognized, the response of carbon dynamics to invasive species remains largely unknown. We report new CO2 data showing significant increases in pCO2 (up to 800 μatm in Lake Michigan) and CO2 emission fluxes in most of the Great Lakes compared to those prior to or during the early stage of the colonization of invasive quagga mussels. The increased CO2 supersaturation is most prominent in Lakes Huron and Michigan, followed by Lakes Ontario and Erie, but no evident change was observed in Lake Superior. This trend mirrors the infestation extent of invasive quagga mussels in the Great Lakes and is consistent with the decline in primary production and increase in water clarity observed pre- and post-Dreissena introduction, revealing a close linkage between invasive species and carbon dynamics. The Great Lakes have become a significant CO2 source to the atmosphere, emitting >7.7 ± 1.0 Tg-C annually, which is higher than the organic carbon burial rate in global inland-seas and attesting to the significant role of the Laurentian Great Lakes in regional/global CO2 budget and cycling.

  14. [Limnology of high mountain tropical lake, in Ecuador: characteristics of sediments and rate of sedimentation].

    PubMed

    Gunkel, Günter

    2003-06-01

    Equatorial high mountain lakes are a special type of lake occurring mainly in the South American Andes as well as in Central Africa and Asia. They occur at altitudes of a few thousand meters above sea level and are cold-water lakes (< 20 degrees C). Relatively little is known about them. A long-term limnological study was therefore undertaken at Lake San Pablo, Ecuador, to analyze the basic limnological processes of the lake, which has a tendency for eutrophication. Sediment quality of San Pablo Lake is given under consideration of horizontal and vertical distribution using sediment cores. Significance of sediments for eutrophication process of lakes is demonstrated using phosphorus concentration of sediments as well as the phosphorus retention capacity of the sediments by ratio Fe/P. Dating of the sediments is done using 137Cs and 210Pb, but the activity of 137Cs in the sediment was very low nearly at the detection level. Sedimentation rate is determined to be 3.5 mm/year and the sediment cores represent about 110 years. P concentration of the sediments is high (approximately 5 g/kg dry substance), and P retention capacity by Fe is insufficient (Fe/P = 4). The sediment quality did not change significantly during the past decades, and the trophic state of San Pablo Lake was already less or more eutrophic 110 years ago. The contamination of the lake sediments by heavy metals is insignificant.

  15. Do invasive quagga mussels alter CO2 dynamics in the Laurentian Great Lakes?

    PubMed

    Lin, Peng; Guo, Laodong

    2016-12-20

    The Laurentian Great Lakes have experienced unprecedented ecological and environmental changes, especially after the introduction of invasive quagga mussel (Dreissena rostriformis bugensis). While impacts on ecological functions have been widely recognized, the response of carbon dynamics to invasive species remains largely unknown. We report new CO2 data showing significant increases in pCO2 (up to 800 μatm in Lake Michigan) and CO2 emission fluxes in most of the Great Lakes compared to those prior to or during the early stage of the colonization of invasive quagga mussels. The increased CO2 supersaturation is most prominent in Lakes Huron and Michigan, followed by Lakes Ontario and Erie, but no evident change was observed in Lake Superior. This trend mirrors the infestation extent of invasive quagga mussels in the Great Lakes and is consistent with the decline in primary production and increase in water clarity observed pre- and post-Dreissena introduction, revealing a close linkage between invasive species and carbon dynamics. The Great Lakes have become a significant CO2 source to the atmosphere, emitting >7.7 ± 1.0 Tg-C annually, which is higher than the organic carbon burial rate in global inland-seas and attesting to the significant role of the Laurentian Great Lakes in regional/global CO2 budget and cycling.

  16. Winter Lake Breezes near the Great Salt Lake

    NASA Astrophysics Data System (ADS)

    Crosman, Erik T.; Horel, John D.

    2016-05-01

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

  17. Sea Clutter

    DTIC Science & Technology

    1990-09-28

    OE-10, 47i- 476, (1985). 15. S. Tang and 0. H. Shemdin , "Measurement of High-frequency Waves using a Wave Fol- lower," J. Geophys. Res. 88. 9832...DESCRIPTION OF THE SEA SURFACE ................................................................... 2 The Wave Spectrum...Very Low Grazing Angles ......................................................................... 16 At HF and mm- Wave Frequencies

  18. 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.

  19. Examining indirect effects of lake trout recovery

    EPA Science Inventory

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

  20. 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

  1. 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.

  2. Neutrino astrophysics experiments beneath the sea and ice.

    PubMed

    Halzen, Francis

    2007-01-05

    Neutrino astronomy beyond the Sun was first imagined in the late 1950s. A neutrino detector at the bottom of Lake Baikal, the deployment of detectors in the Mediterranean Sea, and the construction of a kilometer-scale neutrino telescope at the South Pole exemplify current efforts to realize this dream.

  3. Enhanced ice sheet growth in Eurasia owing to adjacent ice-dammed lakes.

    PubMed

    Krinner, G; Mangerud, J; Jakobsson, M; Crucifix, M; Ritz, C; Svendsen, J I

    2004-01-29

    Large proglacial lakes cool regional summer climate because of their large heat capacity, and have been shown to modify precipitation through mesoscale atmospheric feedbacks, as in the case of Lake Agassiz. Several large ice-dammed lakes, with a combined area twice that of the Caspian Sea, were formed in northern Eurasia about 90,000 years ago, during the last glacial period when an ice sheet centred over the Barents and Kara seas blocked the large northbound Russian rivers. Here we present high-resolution simulations with an atmospheric general circulation model that explicitly simulates the surface mass balance of the ice sheet. We show that the main influence of the Eurasian proglacial lakes was a significant reduction of ice sheet melting at the southern margin of the Barents-Kara ice sheet through strong regional summer cooling over large parts of Russia. In our simulations, the summer melt reduction clearly outweighs lake-induced decreases in moisture and hence snowfall, such as has been reported earlier for Lake Agassiz. We conclude that the summer cooling mechanism from proglacial lakes accelerated ice sheet growth and delayed ice sheet decay in Eurasia and probably also in North America.

  4. Relative abundance, site fidelity, and survival of adult lake trout in Lake Michigan from 1999 to 2001: Implications for future restoration strategies

    USGS Publications Warehouse

    Bronte, C.R.; Holey, M.E.; Madenjian, C.P.; Jonas, J.L.; Claramunt, R.M.; McKee, P.C.; Toneys, M.L.; Ebener, M.P.; Breidert, B.; Fleischer, G.W.; Hess, R.; Martell, A.W.; Olsen, E.J.

    2007-01-01

    We compared the relative abundance of lake trout Salvelinus namaycush spawners in gill nets during fall 1999–2001 in Lake Michigan at 19 stocked spawning sites with that at 25 unstocked sites to evaluate how effective site-specific stocking was in recolonizing historically important spawning reefs. The abundance of adult fish was higher at stocked onshore and offshore sites than at unstocked sites. This suggests that site-specific stocking is more effective at establishing spawning aggregations than relying on the ability of hatchery-reared lake trout to find spawning reefs, especially those offshore. Spawner densities were generally too low and too young at most sites to expect significant natural reproduction. However, densities were sufficiently high at some sites for reproduction to occur and therefore the lack of recruitment was attributable to other factors. Less than 3% of all spawners could have been wild fish, which indicates that little natural reproduction occurred in past years. Wounding by sea lamprey Petromyzon marinus was generally lower for Seneca Lake strain fish and highest for strains from Lake Superior. Fish captured at offshore sites in southern Lake Michigan had the lowest probability of wounding, while fish at onshore sites in northern Lake Michigan had the highest probability. The relative survival of the Seneca Lake strain was higher than that of the Lewis Lake or the Marquette strains for the older year-classes examined. Survival differences among strains were less evident for younger year-classes. Recaptures of coded-wire-tagged fish of five strains indicated that most fish returned to their stocking site or to a nearby site and that dispersal from stocking sites during spawning was about 100 km. Restoration strategies should rely on site-specific stocking of lake trout strains with good survival at selected historically important offshore spawning sites to increase egg deposition and the probability of natural reproduction in Lake

  5. Water input requirements of the rapidly shrinking Dead Sea.

    PubMed

    Abu Ghazleh, Shahrazad; Hartmann, Jens; Jansen, Nils; Kempe, Stephan

    2009-05-01

    The deepest point on Earth, the Dead Sea level, has been dropping alarmingly since 1978 by 0.7 m/a on average due to the accelerating water consumption in the Jordan catchment and stood in 2008 at 420 m below sea level. In this study, a terrain model of the surface area and water volume of the Dead Sea was developed from the Shuttle Radar Topography Mission data using ArcGIS. The model shows that the lake shrinks on average by 4 km(2)/a in area and by 0.47 km(3)/a in volume, amounting to a cumulative loss of 14 km(3) in the last 30 years. The receding level leaves almost annually erosional terraces, recorded here for the first time by Differential Global Positioning System field surveys. The terrace altitudes were correlated among the different profiles and dated to specific years of the lake level regression, illustrating the tight correlation between the morphology of the terrace sequence and the receding lake level. Our volume-level model described here and previous work on groundwater inflow suggest that the projected Dead Sea-Red Sea channel or the Mediterranean-Dead Sea channel must have a carrying capacity of >0.9 km(3)/a in order to slowly re-fill the lake to its former level and to create a sustainable system of electricity generation and freshwater production by desalinization. Moreover, such a channel will maintain tourism and potash industry on both sides of the Dead Sea and reduce the natural hazard caused by the recession.

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

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

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

  7. Lake Michigan lake trout PCB model forecast post audit

    EPA Science Inventory

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

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

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

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

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

    EPA Science Inventory

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

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

    EPA Pesticide Factsheets

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

  11. 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 (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.

  12. Early mortality syndrome in Great Lakes salmonines

    USGS Publications Warehouse

    Honeyfield, Dale C.; Brown, Scott B.; Fitzsimons, John D.; Tillitt, Donald E.

    2005-01-01

    Early mortality syndrome (EMS) is the termused to describe an embryonic mortality affectingthe offspring of salmonines (coho salmonOnco-rhynchus kisutch, Chinook salmonOncorhynchustshawytscha, steelhead [anadromous rainbow troutOncorhynchus mykiss], brown troutSalmo trutta,and lake trout,Salvelinus namaycush) in LakesMichigan and Ontario and, to a lesser extent, LakesHuron and Erie (Marcquenski and Brown 1997).Clinical signs of EMS include loss of equilibrium,a spiral swimming pattern, lethargy, hyperexcit-ability, hemorrhage, and death between hatch andfirst feeding. Early mortality syndrome was ob-served as far back as the 1960s in Great Lakessalmonines (Marcquenski and Brown 1997; Fitz-simons et al. 1999) and is of concern because mor-tality has been high in recent years (Wolgamoodet al. 2005; all 2005 citations are this issue). Stocksof Atlantic salmonSalmo salarfrom the FingerLakes and the Baltic Sea also exhibit a similarearly life stage mortality, called Cayuga syndrome(Fisher et al. 1995) and M74 (Bo ̈ rjeson and Norr-gren 1997), respectively. Low egg thiamine levelsand enhanced survival following thiamine treat-ments are common characteristics of EMS, CayugaSyndrome, and M74 (Fitzsimons et al. 1999). Be-cause the deficiency does not appear to be the re-sult of inadequate dietary thiamine (Fitzsimons and Brown 1998), investigators have hypothesizedthat the presence of some thiaminolytic factors inthe diet may reduce the bioavailability of thiamine,either by destroying it or converting it to an in-active analog or thiamine antagonist (Fisher et al.1996; Fitzsimons et al. 1999).

  13. National Lakes Assessment 2007 Results

    EPA Pesticide Factsheets

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

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

    USGS Publications Warehouse

    Davis, N.K.; Locke, W. W.; 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.

  15. Paleo Tibetan Lake Extent Mapping from High-Resolution Satellite Imagery and Digital Elevation Models: A Case Study of Dagze Lake

    NASA Astrophysics Data System (ADS)

    Sheng, Y.; Shah, C. A.; Smith, L. C.; Kroll, C. N.; Li, X.; Wu, Y.; Yao, T.

    2006-12-01

    Dagze Lake, one of many inland lakes in Tibet, with a present area of 243 km2 and water level at ~4466 m above the mean sea level (msl). The lake exhibits a typical pattern of shrinkage in a 2000 Landsat/ETM+ image, with numerous concentric rings of paleo shorelines around it. Using this mapping environment, the paleo water level was determined to be 4520 m (msl), and the paleo lake extent to be 819.3 km2, approximately three times its present extent. As computed from the DEM data, the lake shrinkage caused a loss of ~ 29.2 km3 water. Like Dagze Lake, modern lakes surrounded by paleo shorelines are common in ETM+ imagery across the Tibetan Plateau. With the help of the interactive mapping environment, we expect to recover the spatial extent and volume during the last GLP period for most Tibetan lakes, whose paleo shorelines are visible in high-resolution imagery.

  16. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"…

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

    PubMed

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

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences.

  18. On The Black Sea Surozhian

    NASA Astrophysics Data System (ADS)

    Caraivan, Glicherie; Corneliu, Cerchia

    2016-04-01

    stratotypes", show ages between 27390 - 42120 y BP. Our AMS C14 data on Surozhian mollusk indicate ages between 47359 - 53690 cal. y BP. We argue that "Surozhian" is likely the classic "Karangatian" defined by Nevesskaia that does not correspond to the Riss-Wurm, but to the Middle Wurm instead. The generally accepted "Karangatian", placed in the Riss-Wurm interval is much older. Similarly, the Surozhian (transgressive) cannot be Tarhankutian (regressive). References Caraivan, G., 2010. Studiul sedimentologic al depozitelor de plajǎ si de selful intern al M\\varii Negre între Portița si Tuzla. [Sedimentological Study of Beach and Inner Shelf Romanian Black Sea Deposits]. Ex Ponto, Constanta. (In Romanian) Caraivan, G., Fulga, C., Opreanu, P., 2012. Upper Quaternary evolution of the Mamaia Lake area (Romanian Black Sea shore). Quaternary International 261: 14-20. Caraivan, G., Opreanu, P., Voinea, V., Pojar, I., Sava, T., Giosan, L. „Holocene landscape changes and human communities' migration in the western part of the Black Sea (Mamaia Lake area)", In: IGCP 610 Proceedings of the Third Plenary Conference, Astrakhan, Russia, 22-30 September 2015. Giosan L.et al, 2012. Early Anthropogenic Transformation of the Danube-Black Sea System. Sci Rep. 2012; 2:582 Nevesskaia, L.A. 1965. Pozdrecetverticinîe dvustvorcestîe molluski Cernogo Moria, ih sistematica i ekologhia, Trudî Pal. Inst., 105, Moskva. Shcherbakov, F.A., Koreneva, E.V., and Zabelina, E.K., 1977. Stratigrafiia pozdnechetvertichnykh otlozhenii Chernogo moria [Stratigraphy of the Late Quaternary deposits in the Black Sea]. In Pozdnechetvertichnaia istoriia i sedimentogenez okrainikh i vnutrennikh morei [Late-Quaternary History and Sedimentogenesis in Marginal and Inland Seas]. Nauka, Moscow, pp. 46-51. Yanko-Hombach, V.V., 2007. Controversy over Noah's Flood in the Black Sea: Geological and foraminiferal evidence from the shelf. In Yanko-Hombach, V., Gilbert, A.S., Panin, N., and Dolukanov, P.M. (eds.), [The Black

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