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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...: The meeting will be held at the Lake Champlain Basin Program/Vermont Fish and Wildlife...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... 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... primary meeting date. ADDRESSES: The meeting will be held at the Lake Champlain Basin Program/Vermont...

  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

    ... Office of the Secretary: Renewal of the Lake Champlain Sea Lamprey Control Alternatives Workgroup AGENCY... Champlain Sea Lamprey Control Alternatives Workgroup (Workgroup) for 2 years. The Workgroup provides an... lamprey control techniques alternative to lampricides in Lake Champlain. FOR FURTHER INFORMATION...

  4. Genetic models reveal historical patterns of sea lamprey population fluctuations within Lake Champlain

    PubMed Central

    Azodi, Christina B.; Sheldon, Sallie P.; Trombulak, Stephen C.; Ardren, William R.

    2015-01-01

    The origin of sea lamprey (Petromyzon marinus) in Lake Champlain has been heavily debated over the past decade. Given the lack of historical documentation, two competing hypotheses have emerged in the literature. First, it has been argued that the relatively recent population size increase and concomitant rise in wounding rates on prey populations are indicative of an invasive population that entered the lake through the Champlain Canal. Second, recent genetic evidence suggests a post-glacial colonization at the end of the Pleistocene, approximately 11,000 years ago. One limitation to resolving the origin of sea lamprey in Lake Champlain is a lack of historical and current measures of population size. In this study, the issue of population size was explicitly addressed using nuclear (nDNA) and mitochondrial DNA (mtDNA) markers to estimate historical demography with genetic models. Haplotype network analysis, mismatch analysis, and summary statistics based on mtDNA noncoding sequences for NCI (479 bp) and NCII (173 bp) all indicate a recent population expansion. Coalescent models based on mtDNA and nDNA identified two potential demographic events: a population decline followed by a very recent population expansion. The decline in effective population size may correlate with land-use and fishing pressure changes post-European settlement, while the recent expansion may be associated with the implementation of the salmonid stocking program in the 1970s. These results are most consistent with the hypothesis that sea lamprey are native to Lake Champlain; however, the credibility intervals around parameter estimates demonstrate that there is uncertainty regarding the magnitude and timing of past demographic events. PMID:26539334

  5. 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.

  6. 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...

  7. 33 CFR 117.797 - Lake Champlain.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  8. 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...

  9. 33 CFR 117.797 - Lake Champlain.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  10. 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...

  11. 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.

  12. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... bridge. (c) The draw of the Central Vermont Railway bridge across Missisquoi Bay, mile 105.6 shall open... 117.993 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES... vessels of the United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain,...

  13. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... bridge. (c) The draw of the Central Vermont Railway bridge across Missisquoi Bay, mile 105.6 shall open... 117.993 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES... vessels of the United States. (b) The draw of the US2 Bridge, mile 91.8, over Lake Champlain,...

  14. 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. 110.136 Section 110.136 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.136 Lake Champlain, NY and VT. (a) Burlington...

  15. 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.

  16. 78 FR 14444 - Drawbridge Operation Regulation; Lake Champlain, Swanton, VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-06

    ... the bridge. (4) A sufficient number of infrared cameras shall be maintained in good working order at... infrared cameras to verify that the channel is clear of all approaching vessel traffic. All approaching... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Lake Champlain,...

  17. 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.

  18. 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

  19. Mercury in the pelagic food web of Lake Champlain.

    PubMed

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

    2012-04-01

    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 25-75% 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.

  20. 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.

  1. 75 FR 22228 - Regulated Navigation Area; Lake Champlain Bridge Construction Zone, NY and VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-28

    ... FR 3316). Public Meeting We do not now plan to hold a public meeting. You may submit a request for... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA11 Regulated Navigation Area; Lake Champlain Bridge... Lake Champlain Bridge between Crown Point, New York and Chimney Point, Vermont. This temporary...

  2. 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, N.Y. An area shoreward of a line bearing 312° from Ticonderoga Light to the southeast corner of...

  3. 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.

  4. 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

    ... Champlain Bridge Construction Zone (Between Vermont and New York), Crown Point, NY AGENCY: Coast Guard, DHS... navigable waters immediately surrounding the Lake Champlain Bridge construction zone between Chimney Point... the completion of the removal of debris from the old Crown Point bridge demolition. The debris must...

  5. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  7. 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.

  8. 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.

  9. 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

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

    USGS Publications Warehouse

    Flynn, Robert H.; Hayes, Laura

    2016-01-01

    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

  11. 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...

  12. 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...

  13. 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.

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

    PubMed Central

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

    2012-01-01

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

  15. Astronauts Conrad and Cooper slice cake on U.S.S. Lake Champlain

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronauts Charles Conrad Jr. (left) and L. Gordon Cooper Jr. prepate to slice into the huge cake prepared for them by the cooks onboard the aircraft carrier U.S.S. Lake Champlain. They are using ornamental Navy swords for knives.

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

    NASA Technical Reports Server (NTRS)

    1965-01-01

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

  17. Quantifying sediment loadings from streambank erosion in selected agricultural watersheds draining to Lake Champlain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At its mouth on Lake Champlain the Missisquoi River has a history of exceedance of phosphorus concentration target levels endorsed by the governments of Vermont, Québec, and New York. Observations along the study reach of the Missisquoi River and several of its tributaries have indicated that the r...

  18. 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.

  19. 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. PMID:25193831

  20. 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.

  1. 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

  2. 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

  3. Accumulation of polychlorinated biphenyl congeners from Lake Champlain sediments by Mysis relicta

    SciTech Connect

    Lester, D.C.; McIntosh, A. . Vermont Water Resources and Lake Studies Center)

    1994-11-01

    Polychlorinated biphenyl (PCB) levels in lake trout (Salvelinus namaycush) from Lake Champlain often exceed the F.D.A. tolerance level of 2 [mu]g/g (wet weight). Of added concern are recent studies that suggest a relationship between the dioxin-like properties of non-ortho-substituted PCB congeners and impaired lake trout egg hatchability. Dietary accumulation of PCBs is thought to be an important exposure route for fish. The epibenthic freshwater shrimp Mysis relicta is an integral part of the benthic and pelagic food web in lake Champlain and may act as a link between PCBs in sediments and lake trout. Previous investigations have shown that diurnal migrations of mysids enhance the movement and distribution of toxic contaminants, effectively coupling the benthic and pelagic zones. The objective of this research was to examine the role contaminated sediments play in the transfer of PCBs to mysids. Bioaccumulation was assessed by exposing mysids to such sediments in two ways: (a) with organisms screened from sediments; and (b) with organisms in direct contact with sediments. Accumulation of PCBs over the course of the 24-day exposure period was examined on the following days: 0, 3, 6, 12, 21, and 24. Eighty-nine individual PCB congeners were measured in tissue and sediment. Mysids in direct contact with sediments accumulated significantly higher levels of PCBs than did organisms screened from sediments. Mysids accumulated substantial levels of PCBs, suggesting they may play an important part in the transfer of PCBs from sediments into the Lake Champlain food web. It is clear from this research that sediments can play a critical role in the accumulation of PCBs by mysids.

  4. 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

  5. Remote sensing models using Landsat satellite data to monitor algal blooms in Lake Champlain.

    PubMed

    Trescott, A; Park, M-H

    2013-01-01

    Lake Champlain is significantly impaired by excess phosphorus loading, requiring frequent lake-wide monitoring for eutrophic conditions and algal blooms. Satellite remote sensing provides regular, synoptic coverage of algal production over large areas with better spatial and temporal resolution compared with in situ monitoring. This study developed two algal production models using Landsat Enhanced Thematic Mapper Plus (ETM(+)) satellite imagery: a single band model and a band ratio model. The models predicted chlorophyll a concentrations to estimate algal cell densities throughout Lake Champlain. Each model was calibrated with in situ data compiled from summer 2006 (July 24 to September 10), and then validated with data for individual days in August 2007 and 2008. Validation results for the final single band and band ratio models produced Nash-Sutcliffe efficiency (NSE) coefficients of 0.65 and 0.66, respectively, confirming satisfactory model performance for both models. Because these models have been validated over multiple days and years, they can be applied for continuous monitoring of the lake.

  6. 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.

  7. Modeling 200 Years of Changing Trophic Status in Lake Champlain Based on Land Use Change and Commercial Practices

    NASA Astrophysics Data System (ADS)

    Carr, H. E.; Boumans, R.; Levine, S.

    2009-12-01

    Paleolimnological records show that since Europeans began settling in the Lake Champlain Basin almost 250 years ago, the lake has become progressively eutrophic. Eutrophication of freshwater bodies through input of excess nutrients has been a major water quality issue worldwide for the past half century (Codd et al. 2005). While the underlying causes of productivity rise in Lake Champlain, such as deforestation, increasing population, and lake level changes, have been inferred from anecdotal evidence, quantitative inferences based on modeled nutrient fluxes are lacking. Land use changes, such as the switch from subsistence farming to commercial practices focusing on one or two crops or animal types, as well as massive deforestation in 19th century, may explain some of the observed variability in nutrient and algal biomass accumulation rates since settlement began. While increased sampling of the Lake Champlain increases the amount of paleolimnological data, researching the historic information of the area gives a more complete grasp of the past drivers in land use change. In order to manage the historical land use data that are currently available, a simulation model was developed in Simile, a declarative programming software, to simulate algal productivity in response to phosphorous load based on alterations in land use, population, livestock numbers, fertilizer use, waste water treatment effluent, precipitation, and lake level. Data within the Lake Champlain Basin from the past two centuries were gathered from various online sources and individuals who had previously collected data. The output from the model was compared with phosphorus and algal pigment profiles in sediment cores collected from several locations in Lake Champlain. These show phosphorous accumulation rate and algal productivity increasing over the past 200 years, but do not indicate the reasons for change (Levine and Lini, unpublished data). Ongoing research is increasing data availability and

  8. 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.

  9. 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

    .... (b) Regulations. In addition to 33 CFR 165.10, 165.11, and 165.13, the following restrictions or conditions apply within this RNA: (1) No vessel may operate at a speed in excess of five knots. (2) All... of the regulated navigation area (RNA). All navigable waters on Lake Champlain 300 yards to the...

  10. 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

    .... (b) Regulations. In addition to 33 CFR 165.10, 165.11, and 165.13, the following restrictions or conditions apply within this RNA: (1) No vessel may operate at a speed in excess of five knots. (2) All... of the regulated navigation area (RNA). All navigable waters on Lake Champlain 300 yards to the...

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

    USGS Publications Warehouse

    Flynn, Robert H.; Rydlund, 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.

  12. Streamwater fluxes of total mercury and methylmercury into and out of Lake Champlain.

    PubMed

    Shanley, James B; Chalmers, Ann T

    2012-02-01

    From 2000 to 2004, we sampled for total mercury (THg) and methylmercury (MeHg) in inlet streams to Lake Champlain, targeting high flow periods to capture increases in THg and MeHg concentrations with increasing flow. We used these data to model stream THg and MeHg fluxes for Water Years 2001 through 2009. In this mountainous forested basin with a high watershed-to-lake area ratio of 18, fluvial export from the terrestrial watershed was the dominant source of Hg to the lake. Unfiltered THg and MeHg fluxes were dominated by the particulate fraction; about 40% of stream THg was in the filtered (<0.4 μm) phase. THg flux from the watershed to the lake averaged 2.37 μg m(-2) yr(-1), or about 13% of atmospheric Hg wet and dry deposition to the basin. THg export from the lake represented only about 3% of atmospheric Hg input to the basin.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

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

    PubMed

    Torbick, Nathan; Corbiere, Megan

    2015-09-15

    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 chlorophylla 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.

  19. 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.

  20. 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.

  1. Application of the WHO alert level framework to cyanobacterial monitoring of Lake Champlain, Vermont.

    PubMed

    Watzin, Mary C; Miller, Emily Brines; Shambaugh, Angela D; Kreider, Meghan A

    2006-06-01

    The increasing incidence of toxic cyanobacteria blooms worldwide has created a need for practical and efficient monitoring in order to protect public health. We developed a monitoring and alert framework based on World Health Organization (WHO) recommendations and applied it on Lake Champlain during the summers of 2002-2004. The protocol began with collection of net samples of phytoplankton in order to maximize the chance of finding potential toxin-producing cyanobacteria. Samples were collected lake-wide in partnership with ongoing monitoring efforts, but because open water sample sites did not capture conditions along the shoreline, we added near-shore and shoreline stations in problem areas. Samples were examined qualitatively until potential toxin-producing taxa were found. Then quantitative analyses began, using a rapid screening method to estimate cell density based on colony size. A final cell density of 4000 cells/mL triggered toxin analyses. Primary analysis was for microcystins using ELISA methods. Cell densities, locations of colonies, and toxin concentrations were reported weekly to public health officials. We found that screening for potential toxin-producing cyanobacteria and then measuring toxin concentrations when cell densities reached critical levels worked well to identify problem locations. Although the WHO recommends using chlorophyll a concentration, it was not a good indicator of problem densities of potential toxin-producing cyanobacteria. Our cell density screening method missed no developing blooms but produced less precise density estimates at high cell counts. Overall, our framework appears to provide an efficient and effective method for monitoring cyanotoxin risks.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Phosphorus Characterization and Contribution from Eroding Streambank Soils of Vermont's Lake Champlain Basin.

    PubMed

    Ishee, Eulaila R; Ross, Donald S; Garvey, Kerrie M; Bourgault, Rebecca R; Ford, Charlotte R

    2015-11-01

    Streambank erosion is an important contributor to sediment and nutrient export. This study determined total P (TP), soil-test P (Modified Morgan's, MM-P), and the degree of P saturation (DPS) in eroding riparian soils along four Lake Champlain Basin stream corridors. We investigated the relationship between these data and soil texture and with a series of GIS-derived landscape metrics. We also quantified the potential P load from eroding streambanks using remote sensing. Soil samples were taken from 76 erosion features to a depth of 90 cm on four streams in Chittenden County, Vermont. Mean concentrations of TP and MM-P were similar among the watersheds and through depth. Neither TP, MM-P, nor DPS were well related to texture. Metrics from available spatial databases for parent material, soil series, and landscape position were somewhat useful in predicting TP and MM-P. Eroding streambank soil from 2004 through 2007 in the four streams was estimated to contain from 0.5 to 3.9 Mg of TP and 1.4 to 10.9 kg MM-P. The mean DPS in each watershed was <18% and, along with low MM-P concentrations, suggests that eroded streambanks may act as sinks rather than sources of P. The portion of total nonpoint P export potentially contributed by streambank erosion ranged from 6% in the stream with the lowest erosion rate to 30% in the stream with the highest erosion rate. Based on TP values, the P contribution of these streambanks could be considerable, and more information is needed on their actual contribution to bioavailable P in receiving waters. PMID:26641326

  7. 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

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

    USGS Publications Warehouse

    Flynn, Robert H.; Rydlund, 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 deve

  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

    ... Wildlife Resources Office, on potential for using Genetically Modified Organism (GMO) technology to control... FR 18112) under the Federal Advisory Committee Act (5 U.S.C. App.). The Workgroup's...

  13. Assessing sediment quality in heterogeneous environments: A case study of a small urban harbor in Lake Champlain, Vermont, USA

    SciTech Connect

    Watzin, M.C.; McIntosh, A.W.; Brown, E.A.; Lacey, R.; Lester, D.C.; Newbrough, K.L.; Williams, A.R.

    1997-10-01

    Relatively few case studies have been conducted demonstrating the utility of multiple endpoint approaches to sediment quality assessment in areas with moderate contaminant levels and heterogeneous conditions. Because variability is commonplace in natural systems, assessment approaches must be designed explicitly for these conditions. In an assessment of highly heterogeneous freshwater sediments in Lake Champlain, Vermont, USA, the authors measured multiple endpoints, including physical and chemical characteristics of the sediment, acute and chronic toxicity in three tests (Ceriodaphnia dubia, Chironomus tentans, and Pimephales promelas), and benthic community composition, at 19 sites throughout Inner Burlington Harbor. Multiple regression techniques were used to investigate whether significant relationships existed between biological endpoints and the physical and chemical characteristics of the sediments. Although all three laboratory exposures indicated toxicity at some sites, little correspondence was found among the tests. No changes in the benthic community could be attributed to trace contaminants. Multiple regression was useful in showing associations between contaminants, grain size, toxicity, and benthic community composition. Although not demonstrating causal linkages, these statistical analyses suggested which factors might be important in driving measured responses. In heterogeneous sites, an individualized assessment approach based on a preliminary analysis of variability might provide the most useful information.

  14. 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

  15. 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.

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

    USGS Publications Warehouse

    Medalie, Laura

    2014-01-01

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

  17. Erosion and channel change as factors of landslides and valley formation in Champlain Sea Clays: The Chacoura River, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Lévy, Sébastien; Jaboyedoff, Michel; Locat, Jacques; Demers, Denis

    2012-04-01

    The Champlain Sea clays of Eastern Canada are incised by numerous rivers. Their slopes have been modified by landslides: on the Chacoura River near Trois-Rivières (Quebec), several large landslide scars, more or less recent, are visible. The role of erosion (channel incision, lateral channel migration and erosion of slopes due to agricultural drainage) as a trigger of these landslides is important. The aim of this study is to understand how erosion and landslides are related to valley development. From a detailed analysis of aerial photographs and DEMs, a map of the phenomena has been drawn by identifying various elements such as landslides, limits of the slope, position of the channel, and the area covered by forest. It is shown that channel change and erosion are strongly linked to landslides by the fact that they change the bank morphology in an unstable way. A slide in itself is a natural way for the slope to achieve stability. But when it occurs in a stream, it creates a disturbance to the stream flow enhancing local erosion which may change the river path and generate more erosion downstream or upstream resulting in more slides. Cross-valley sections and a longitudinal profile show that landslides are a major factor of valley formation. It appears that the upper part of the Chacoura River valley is still unaffected by landslides and has V-shaped sections. The lower part has been subject to intense erosion and many landslide scars can be seen. This shows that the valley morphology is transient, and that future activity is more likely to occur in the upper part of the river. Therefore the identification of areas prone to erosion will help determine the possible location of future large landslides just like the ones that occurred in the lower part.

  18. 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

  19. Headwater locations of U.S. streams tributary to St. Lawrence River basin between western Ohio and eastern New York, excluding Lake Champlain basin

    USGS Publications Warehouse

    Eissler, Benjamin B.

    1979-01-01

    The headwater locations of several thousand U.S. streams tributary to Lakes Ontario and Erie and the St. Lawrence and Niagara Rivers, from the Maumee River in Ohio to the western border of the Lake Champlain basin in New York, including parts of Pennsylvania, are listed by quadrangle. The location of the headwater of each is given with reference to cultural and topographic features. ' Headwater ' in this report is defined as the first site downstream from which the average streamflow is 5 cubic feet per second. The site locations were determined from drainage areas as indicated on topographic maps. The size of the drainage area required to produce an average flow of 5 cubic feet per second was determined from equations, developed separately for each State by regression techniques, that define the relation between streamflow and hydrologic factors of the region. Drainage area and precipitation were factors in the equations for all three States: forest cover was found to be significant in Ohio. (Woodard-USGS)

  20. 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

  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. 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

  3. 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

  4. Tidal Response of Titan's Lakes and Seas

    NASA Astrophysics Data System (ADS)

    Karatekin, O.; Demain, C.; Deleersnijder, E.

    2011-12-01

    The Cassini spacecraft has revealed a vast set of lakes/seas filled or partially filled with liquid hydrocarbons and empty lake basins in the high latitudes of Titan. The seas and lakes of Titan provide an opportunity to explore an exciting aqueous environment whose characteristics are very different from what we know on Earth. The lakes appear in various shapes and sizes and are filled with liquid hydrocarbons, primarily methane and ethane. Recently, the Cassini spacecraft provided observations suggesting for the first time temporal variations in lake surfaces. The variation in the shorelines can be explained by different hypothesis including evaporation and tides. During Titan's 16 day orbital period around Saturn, the time-dependent tidal response of the lakes may affect the shorelines. Although the estimated tidal amplitudes by theoretical consideration yield smaller than the observed depth changes on Ontario Lacus, tides can have more significant effects of other lakes/seas with tidal amplitudes up to several meters. In the present study, besides Ontario Lacus we also consider Ligeia Mare, one of three large methane seas discovered by Cassini in the northern hemisphere of Titan and the target for the discovery mission of Titan Mare Explorer (TiME). The tidal response of Titan's lakes an seas are investigated by means of two- dimensional nonlinear shallow water equations The governing partial differential equations on the sphere are solved using SLIM (Second-generation Louvain- la- Neuve Ice-Ocean Model - http://www.climate.be/SLIM). SLIM is a hydrodynamical model based on finite element method. As all general circulation models, it uses primitive variables as prognostic quantities. Partial differential equations are discretized on curved surfaces using triangular meshes. The mesh is generated from recursive subdivisions of the faces of an icosahedron using GMSH software.. The code has a wetting-drying algorithm. The simulations can take into account several

  5. 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

  6. 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

  7. 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.

  8. 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 focuses on fishing…

  9. 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

  10. Does ice float in Titan’s lakes and seas?

    NASA Astrophysics Data System (ADS)

    Hofgartner, Jason D.; Lunine, Jonathan I.

    2013-03-01

    We model Titan’s lakes and seas as methane-ethane-nitrogen systems and model the buoyancy of solids in these systems assuming thermodynamic equilibrium. We find that ice will float in methane-rich lakes for all temperatures below the freezing point of pure methane and that ice will also float in ethane-rich seas provided the ice has an air porosity of greater than 5% by volume.

  11. 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.

  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. 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.

  14. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 117.993 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES...) A sufficient number of infrared cameras shall be maintained in good working order at all times with... the event that any of the cameras, navigation lights, horn, or message board become...

  15. 33 CFR 117.993 - Lake Champlain.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 117.993 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES...) A sufficient number of infrared cameras shall be maintained in good working order at all times with... the event that any of the cameras, navigation lights, horn, or message board become...

  16. Growth of lake trout in Lake Superior before the maximum abundance of sea lampreys

    USGS Publications Warehouse

    Rahrer, Jerold F.

    1967-01-01

    The growth in length of lake trout (Salvelinus namaycush) from the inshore water of Lake Superior in 1953 increased with age from the 3rd to 9th year, and was nearly constant from the 9th to the 12th year. Growth was greatest in the 1st year (4.0 inches) and least in the 2nd and 3rd years (2.3 inches). Between the 4th and 9th years the increments increased from 2.6 to 3.5 inches. Growth was calculated from a curvilinear body-scale relation. Intraseasonal growth in length extended from late April until well after October; most growth was in late summer and fall. The younger fish started growth earlier, and some mature fish did not increase in length until after the October spawning. Lake trout reached the minimum legal weight (1.5 pounds) in the 7th year of life and the average size taken in the commercial fishery (about 3 pounds) in the 8th year. The annual increase in weight in the 8th year of life was over 64%. Fish used in this study grew more slowly than those from Lakes Michigan and Huron taken during the period when sea lamprey abundance was increasing, but at about the same rate as lake trout of Lake Michigan before the sea lamprey appeared.

  17. 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.

  18. 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.

  19. 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.

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

    PubMed

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

    2010-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    Katz, Amitai; Nishri, Ami

    2013-03-01

    In stratified hardwater lakes, calcite crystallization in the epilimnion and partial dissolution in the hypolimnion play important roles in the cycling of Ca2+ in the water column. Mg2+ and Sr2+ coprecipitate with this mineral, to be released together with Ca2+ upon its dissolution. Here, we focus on Lake Kinneret (Sea of Galilee, Israel), a stratified, warm, hardwater lake, searching for an interpretable, high resolution picture of the processes that drive Ca2+, Mg2+ and Sr2+cycling in this and similar lakes elsewhere. In total, 1428 water samples were collected from the lake, and another 81 samples were collected from the Jordan River and two small streams discharging into it, covering a full monomictic cycle from December 2001 through March 2003. Particulate material was retrieved from sediment traps in the hypolimnion. The water samples were analyzed for Na+, K+, Mg2+, Ca2+, Sr2+, Cl-, SO42-, HCO3- and Br-, and the trapped particulates were examined under SEM and analyzed for their Ca, Mg, and Sr content. Individual calcite crystals within the particulate material underwent LA-ICP-MS analysis for Ca, Mg, and Sr. Downward transport of Ca2+ involves crystallization of calcite in the epilimnion, followed by its settling through the water column, followed by its partial dissolution in the hypolimnion. Magnesium and Sr2+ follow Ca2+ by coprecipitation in calcite and are released upon its dissolution in the hypolimnion. Upward cycling of the three solutes occurs through an admixture of the hypolimnetic water into the epilimnion during thermocline deepening, terminated by overturn of the lake. Removal rates of Mg2+ and Sr2+ from the lake, relative to that of Ca2+, and the water-calcite distribution coefficients, DMg and DSr, were calculated from the analyses using: (1) epilimnion water and 'bulk' particulates; (2) epilimnion water only; and (3) epilimnion water and calcite crystals in the particulates. The DSr values obtained were internally consistent (0.194 ± 5

  10. 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.

  11. 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.

  12. 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.

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

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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.

    2015-01-01

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

    NASA Astrophysics Data System (ADS)

    Normandeau, Alexandre; Lajeunesse, Patrick; Philibert, Geneviève

    2013-09-01

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

  3. 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.

  4. 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.

  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. Tectonic tilt rates derived from lake-level measurements, Salton Sea, California

    SciTech Connect

    Wilson, M.E.; Wood, S.H.

    1980-01-11

    Tectonic tilt at the Salton Sea was calculated by differencing lake-level measurements from two points on the sea. During the past 26 years, tilting was down toward the southeast. By 1970 differential vertical movement amounted to 110 millimeters between two gages situated 38 kilometers apart on the southwest shore. A reversal in tilt direction in late 1972 has diminished the net differential vertical movement to 60 millimeters.

  9. Tectonic tilt rates derived from lake-level measurements, salton sea, california.

    PubMed

    Wilson, M E; Wood, S H

    1980-01-11

    Tectonic tilt at the Salton Sea was calculated by differencing lake-level measurements from two points on the sea. During the past 26 years, tilting was down toward the southeast. By 1970 differential vertical movement amounted to 110 millimeters between two gages situated 38 kilometers apart on the southwest shore. A reversal in tilt direction in late 1972 has diminished the net differential vertical movement to 60 millimeters. PMID:17809103

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

    NASA Astrophysics Data System (ADS)

    Alpar, B.

    2012-04-01

    The Sea of Marmara is connected to the Black Sea through the Bosporus strait. The idea of another waterway existed between these seas during the late Quaternary is much of great interest to scientific community. Taking into account the marine microfaunal composition collected from lake surface sediments some researchers claim that there was an alternative waterway connection via the lakes of Iznik and Sapanca, located at the eastward extensions of the Gulf of Gemlik and Izmit Bay, respectively. In addition a Holocene age is suggested for the latest flooding event. On the contrary, other researchers who have questioned the possibility for a waterway connection through these lakes and the lower course of Sakarya River during the Holocene or the late Pleistocene, claim that a marine connection could not be possible for at least the past 500,000 years. On the basis of the global sea-level change and regional tectonic uplift rates, for example, a connection between the Lake Iznik and the Sea of Marmara may not have been possible after 310,000 years BP. Both of the lakes, representing adjacent E-W-oriented narrow depressions, are controlled by the transpressional effects of the northern and central segments of the North Anatolian Fault (NAF) zone since the Late Miocene - Pliocene. On the basis of available seismic reflection data, the deep trough along the southern margin of Lake Iznik has been evolved under the control of a releasing bend system. Similar to the Hersek Pass separating the outer and central sub-basins of the Izmit Bay at present, this system formed the Karsak Pass between the Lake Iznik and the Gulf of Gemlik, and the brackish waters discharged into the Sea of Marmara. At present, the central segment of the NAF cuts this system and extends towards the Gulf of Gemlik, which is separated from the Lake Iznik by the uplifted Karsak sill (+83 m), similar to the pressure ridge on the Hersek Delta. Therefore the main trough of the Lake Iznik existed before the

  11. 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.

  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. 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…

  14. Assessment of sea lamprey (Petromyzon marinus) predation by recovery of dead lake trout (Salvelinus namaycush) from Lake Ontario, 1982-85

    USGS Publications Warehouse

    Bergstedt, Roger A.; Schneider, Clifford P.

    1988-01-01

    During 1982-85, 89 dead lake trout (Salvelinus namaycush) were recovered with bottom trawls in U.S. waters of Lake Ontario: 28 incidentally during four annual fish-stock assessment surveys and 61 during fall surveys for dead fish. During the assessment surveys, no dead lake trout were recovered in April-June, one was recovered in August, and 27 were recovered in October or November, implying that most mortality from causes other than fishing occurred in the fall. The estimated numbers of dead lake trout between the 30- and 100-m depth contours in U.S. waters ranged from 16 000 (0.08 carcass/ha) in 1983 to 94 000 (0.46 carcass/ha) in 1982. Of 76 carcasses fresh enough to enable recognition of sea lamprey (Petromyzon marinus) wounds, 75 bore fresh wounds. Assuming that sea lamprey wounding rates on dead fish were the same as on live ones of the same length range (430-740 mm), the probability of 75 of the 76 dead lake trout bearing sea lamprey wounds was 3.5 x 10-63 if death was independent of sea lamprey attack, thus strongly implicating sea lampreys as the primary cause of death of fish in the sample. The recovery of only one unwounded dead lake trout also suggested that natural mortality from causes other than sea lamprey attactks is negligible.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 77 FR 67319 - Drawbridge Operation Regulation; Lake Champlain, Swanton, VT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... lights shall display as red to indicate the bridge is in the closed position. Once the train clears the... of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking Sec. Section Symbol U.S.C... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). 4. Public Meeting...

  2. 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.

  3. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (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...

  4. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (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...

  5. 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...

  6. 40 CFR 81.48 - Champlain Valley Interstate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (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...

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  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. Effects of salinity upon evaporation from pans and shallow lakes near the Dead Sea

    NASA Astrophysics Data System (ADS)

    Oroud, I. M.

    1995-09-01

    Evaporation was evaluated for three shallow lakes near the Dead Sea with specific gravities (s.g.) of 1.26, 1.31 and 1.34, and for a hypothetical fresh lake of similar depth. The annual march of lake temperature was adequately predicted with an equilibrium temperature model. Predicted temperatures were only slightly affected by neglecting heat exchange between the lake and the underlying sediments. Modeled lake temperatures were then used in a modified Penman-type model and an “alpha ratio” model to generate evaporation estimates. The evaporation models were verified by comparison against 1950'ies water balance estimates of evaporation from the Dead Sea (s.g. about 1.18). Annual totals of evaporation predicted by the models for the shallow lakes declined from 2125 mm for fresh water (s.g. = 1.0) down to 588 mm for the most saline conditions (s.g. = 1.34). Evaporation was also measured from sunken pans in which s.g. was maintained at 1.0, 1.26, 1.31 and 1.34. Mean monthly pan coefficients (from lake/pan evaporation for equal s.g. values) ranged from 0.63 up to 1.03 as s.g. increased from 1.00 up to 1.34. The variations in coefficients are attributed to effects of salinity on the mechanisms that control the gain and loss of heat to the ponds and evaporation pans. The temperatures of the saline lakes were always somewhat warmer than the temperatures measured in the sunken pans, ranging from + 0.7 °C for s.g. of 1.26 up to + 1.3 °C for s.g. of 1.34; the corresponding value for the fresh condition was — 0.4 °C. The pan coefficients defined here for saline conditions will be useful for estimating actual water loss from brine-filled ponds used in commercial extraction of potash and other chemicals.

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

    NASA Astrophysics Data System (ADS)

    Bloszies, Chris; Forman, Steven L.

    2015-01-01

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

  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

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

    Deep-sea hypersaline anoxic lakes (DHALs) of the Eastern Mediterranean represent some of the most hostile environments on our planet. We investigated microbial life in the recently discovered Lake Medee, the largest DHAL found to-date. Medee has two unique features: a complex geobiochemical stratification and an absence of chemolithoautotrophic Epsilonproteobacteria, which usually play the primary role in dark bicarbonate assimilation in DHALs interfaces. Presumably because of these features, Medee is less productive and exhibits reduced diversity of autochthonous prokaryotes in its interior. Indeed, the brine community almost exclusively consists of the members of euryarchaeal MSBL1 and bacterial KB1 candidate divisions. Our experiments utilizing cultivation and [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. PMID:24352146

  18. 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.

  19. 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).

  20. 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.

  1. 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.

  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. 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

  4. Precipitation regimes in the Levant during the Holocene inferred from Dead Sea lake levels and stochastic modeling

    NASA Astrophysics Data System (ADS)

    Morin, Efrat; Ryb, Tamar; Gavrieli, Ittai; Enzel, Yehouda

    2016-04-01

    The Dead Sea is a terminal lake of one of the largest watersheds in the Levant (~43,000 square km), draining sub-humid to hyperarid climate zones. The large size of the watershed and the synchronous regional pattern of annual precipitation are the main reasons that the Dead Sea lake levels are good proxies for the Levant precipitation. Since the mid-1960s intensive water diversions from this watershed caused a dramatic human-induced level drop (currently >1 m/year). Holocene lake levels were used to infer regional precipitation regimes. Previous studies have associated lake level rises and drops with past wet and dry periods in the region, but their quantitative assessment remains a challenge. Moreover, the attributing of lake levels alterations to changes in precipitation regime still misses natural precipitation variability and there is a need to identify and separate their effects. The current study confronts these basic challenges that underlie the transfer of proxy to climatic parameter procedures. It uses here a unique stochastic framework under which we link precipitation regime with the Dead Sea lake levels, considering changes and trends in both mean and variance. Then we infer Levant precipitation regime during the Holocene. The present mean and variance of annual precipitation and lake levels are represented by (a) Kfar Giladi rain station, determined as the best correlated with natural Dead Sea lake level changes, and, (b) using a water balance model; this allowed simulating mean and variance of annual lake levels. Stochastic simulations included scenarios of changes in precipitation regime considering both constant and trended mean annual precipitation. We assessed probabilities of obtaining specific rises and drops, derived from reconstructed Holocene lake levels, under diverse scenarios. The results suggest that late Holocene precipitation regime could be governed by periods of increasing and decreasing trends of mean annual precipitation in the

  5. 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

  6. 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

  7. 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

  8. 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.

  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. PMID:27061778

  10. (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.

  11. Geomorphology of Lake Lisan terraces along the eastern coast of the Dead Sea, Jordan

    NASA Astrophysics Data System (ADS)

    Abu Ghazleh, Shahrazad; Kempe, Stephan

    2009-07-01

    Lake Lisan, the lake that filled the Jordan graben during the Last Glacial, left behind a well developed sequence of erosional and depositional shore terraces in the south east of the current Dead Sea. These terraces record a series of stillstands that were caused by small transgressions within an overall trend of falling lake levels. The terraces were observed in places where they had not been identified previously. The morphology of the terraces was investigated in six cross-sections using differential GPS altimetry. The levels of the terraces range between - 370 and - 148 m a.s.l. The high stand of Lake Lisan at - 148 m correlates well with the high level of - 150 m reported by Bowman and Gross [Bowman, D., Gross, T., 1992. The highest stand of Lake Lisan: ~ 150 meters below MSL. Israel Journal of Earth-Science 41, 233-237.] along the western coast of Lake Lisan. The lake terraces are horizontal, elongated and tectonically undisturbed, and have a sub-horizontal foreshore (tread) with an average slope of 8.2° and steep backshore cliff (riser) with an average slope of 17.7°. The six cross-sections show a good altitudinal correlation between their terraces. Moreover, the terraces appear in undisturbed continuity on the aerial photos. These morphological characteristics demonstrate that the retreat of the lake was a result of substantial climatic changes, not of tectonic subsidence. In-situ stromatolites were found on most of the terraces, reflecting a shallow water environment and emphasizing that these terraces are recessional. Well-developed desert varnish and Tafoni observed on blocks sitting on the terrace surfaces imply a long period of exposure and a low rate of post lacustrine erosion. The formation of Lisan terraces is constrained mainly by coastal slope, water depth and underlying lithology. The morphological analysis of these terraces allows identification of two kinds of pseudo-terraces, which were formed as a result of tread or riser destruction. U

  12. 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.

  13. 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

    2012-11-01

    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.

  14. [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.

  15. Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California.

    PubMed

    Reese, Brandi Kiel; Anderson, Michael A; Amrhein, Christopher

    2008-11-15

    The Salton Sea is a large shallow saline lake located in southern California that is noted for high sulfate concentrations, substantial algal productivity, and very warm water column temperatures. These conditions are well-suited for sulfide production, and sulfide has been implicated in summer fish kills, although no studies have been conducted to specifically understand hydrogen sulfide production and volatilization there. Despite polymictic mixing patterns and relatively short accumulation periods, the amount of sulfide produced is comparable to meromictic lakes. Sulfide levels in the Salton Sea reached concentrations of 1.2 mmol L(-1) of total free sulfide in the hypolimnion and 5.6 mmol L(-1) in the sediment pore water. Strong winds in late July mixed H2S into the surface water, where it depleted the entire water column of dissolved oxygen and reached a concentration of 0.1 mmol L(-1). Sulfide concentrations exceeded the toxicity threshold of tilapia (Oreochromis mossambicus) and combined with strong anoxia throughout the water column, resulted in a massive fish kill. The mixing of sulfide into the surface waters also increased atmospheric H2S concentrations, reaching 1.0 micromol m(-3). The flux of sulfide from the sediment into the water column was estimated to range from 2-3 mmol m(-2) day(-1) during the winter and up to 8 mmol m(-2) day(-1) during the summer. Application of the two-layer model for volatilization indicates that up to 19 mmol m(-2) day(-1) volatilized from the surface during the mixing event. We estimate that as much as 3400 Mg year(-1) or approximately 26% of sulfide that diffused into the water column from the deepest sediments may have been volatilized to the atmosphere. PMID:18760446

  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. 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

  18. 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)

    Yaltırak, Cenk; Ülgen, Umut B.; Zabcı, Cengiz; Franz, Sven Oliver; Ön, Sena Akçer; Sakınç, Mehmet; Çağatay, M. Namık; Alpar, Bedri; Öztürk, Kurultay; Tunoğlu, Cemal; Ünlü, Selma

    2012-06-01

    The identification of past connection routes between the Black Sea and the Sea of Marmara, other than the traditional one through to the Bosphorus Strait, would be of considerable interest to the international scientific community. Nazik et al. (Geo-Mar Lett 31:75-86 (2011) doi:10.1007/s00367-010-0216-9) suggest the possibility of two alternative waterway connections via lakes Sapanca and İznik. Their Black Sea to Sea of Marmara multi-connection hypothesis, which is based on undated marine fossils collected in both lakes from surficial grab samples, conflicts with many earlier studies. In this contribution, the hypothesis and the underlying data are discussed in the light of previous tectonic, sedimentological and limnological findings showing that it is impossible to have had marine connections through lakes Sapanca and İznik during the last 11.5 ka. Global sea-level trends and tectonic uplift rates would accommodate a connection between the Sea of Marmara and Lake İznik in the middle Pleistocene. Uplift rates for the northern block of the North Anatolian Fault, when compared with the global sea-level curve, clearly indicate that there cannot have been a connection through the İzmit Gulf-Lake Sapanca-Sakarya Valley for at least the past 500 ka. Moreover, borehole sediments along the western shores of Lake Sapanca, which reach down to the bedrock, do not contain any marine fossils.

  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. Numerical simulations of tsunamis generated by underwater volcanic explosions at Karymskoye lake (Kamchatka, Russia) and Kolumbo volcano (Aegean Sea, Greece)

    NASA Astrophysics Data System (ADS)

    Ulvrová, M.; Paris, R.; Kelfoun, K.; Nomikou, P.

    2014-02-01

    Increasing human activities along the coasts of the world provoke the necessity to assess tsunami hazard from different sources (earthquakes, landslides, volcanic activity). In this paper, we simulate tsunamis generated by underwater volcanic explosions from (1) a submerged vent in a shallow water lake (Karymskoye Lake, Kamchatka), and (2) from Kolumbo submarine volcano (7 km NE of Santorini, Aegean Sea, Greece). The 1996 tsunami in Karymskoye lake is a well-documented example and thus serves as a case study for validating the calculations. The numerical model reproduces realistically the tsunami run-ups measured onshore. Systematic numerical study of tsunamis generated by explosions of the Kolumbo volcano is then conducted for a wide range of energies. Results show that in case of reawakening, the Kolumbo volcano might represent a significant tsunami hazard for the northern, eastern and southern coasts of Santorini, even for small-power explosions.

  1. Numerical simulations of tsunami generated by underwater volcanic explosions at Karymskoye lake (Kamchatka, Russia) and Kolumbo volcano (Aegean Sea, Greece)

    NASA Astrophysics Data System (ADS)

    Ulvrová, M.; Paris, R.; Kelfoun, K.; Nomikou, P.

    2013-11-01

    Increasing human activities along the coasts of the world arise the necessity to assess tsunami hazard from different sources (earthquakes, landslides, volcanic activity). In this paper, we simulate tsunamis generated by underwater volcanic explosions from (1) a submerged vent in a shallow water lake (Karymskoye Lake, Kamchatka), and (2) from Kolumbo submarine volcano (7 km NE of Santorini, Aegean Sea, Greece). The 1996 tsunami in Karymskoye lake is a well-documented example and thus serves as a case-study for validating the calculations. The numerical model reproduces realistically the tsunami runups measured onshore. Systematic numerical study of tsunamis generated by explosions of Kolumbo volcano is then conducted for a wide range of energies. Results show that in case of reawakening, Kolumbo volcano might represent a significant tsunami hazard for the northern, eastern and southern coasts of Santorini, even for small-power explosions.

  2. 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. PMID:23977309

  3. 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.

  4. Alluvial deposition and lake-level fluctuations forced by Late Quaternary climate change: the Dead Sea case example

    NASA Astrophysics Data System (ADS)

    Klinger, Y.; Avouac, J. P.; Bourles, D.; Tisnerat, N.

    2003-11-01

    Based on geomorphic observations, we discuss lake-level fluctuations, alluvial deposition and river entrenchment in the Dead Sea-Wadi Araba area. The bulk of alluvium in the northern Wadi Araba was probably deposited before the Lisan period of lake transgression that started at about 70 kyears B.P. The lake reached a maximum elevation about 150 m below sea level (b.s.l.), possibly around 15 cal. kyears B.P. as indicated by the highest preserved beach ridges. Cosmogenic exposure dates show that the ridge material consists mainly of remobilized Pleistocene gravel indicating little sediment supply during most of the Lisan period. During this period, a reduced sediment flux fed subaquatic fan deltas along the margin of the Dead Sea. Wetter conditions settled at the end of this period, the water level rose to about 280 m b.s.l. around 15 kyears B.P. and prevailed in the early Holocene (10.5-7 cal. kyears B.P.). Following that humid period, the lake level dropped and two major episodes of fluvial aggradation occurred during periods of relative low lake level. The first aggradational episode took place between about 7.0 and 6.2 cal. kyears B.P. Beach bars indicate a subsequent lake transgression between 6.2 and 4.4 kyears B.P. up to 350 m b.s.l. The second aggradational episode happened between 4.4 and 2.0 cal. kyears B.P., and was also followed by a late transgression up to 375 m b.s.l., dated to 1960-1715 cal. years B.P. The correlation between low lake level and fluvial aggradation is taken to reflect the synchronous change of the fluvial regime and of the lake hydrologic balance, forced by climate changes, rather than a base-level control. We also exclude large tectonic forcing on fan emplacement and river entrenchment. Alluviation appears in this setting as a very irregular process, characterized by long periods of quiescence alternating with periods of fan build-up, reflecting the transient response of the water drainage system to climate change.

  5. 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.

  6. Remote sensing algorithms for lakes Vattern and Vanern, Sweden, based on the SeaWiFS and MERIS bands

    NASA Astrophysics Data System (ADS)

    Pierson, Donald C.; Stroembeck, Niklas

    2000-12-01

    Through a combination of modeling and field work, we have investigated the possibilities of developing algorithms for the SeaWiFS and MERIS sensors which estimate the concentrations of chlorophyl a and phaeophytin a, dissolved yellow substances, and suspended particulate inorganic material in the upper water layer of Lakes Vaettern, and Vaenern the two largest lakes in Sweden. These concentrations are linked to the absorption and backscattering coefficients through a series of empirical relationships and ultimately radiance reflectance is estimated as a function of the ratio of backscattering to absorption. Model parameterization, i.e. the development of the empirical relationships linking the optically active substances to the inherent optical properties is based on both in situ measurements, and laboratory analyses specific to each lake. The frequency distributions of the optically active concentrations in each lake were estimated form long term monitoring data collected by the Swedish Environmental Protection Agency. Simulations which randomly varied the optically active substances based on their frequency distributions were used to generate synthetic data sets which could be used to examine possible remote sensing algorithms. The results of our modeling, suggest that both SeaWiFS and MERIS can provide useful estimates of yellow substances and SPIM in these two lakes. Accurate estimates of chlorophyll depend on measurements of radiance reflectance in the 660nm-680nm chlorophyll absorption band, in order to minimize interference from yellow substance absorption. As a result only the MERIS band 9: band 7 ratio was able to provide useful estimates of chlorophyll concentrations, and the accuracy of these estimates was influenced by variations in yellow substance absorption and variations in the shape of yellow substance absorption spectra measured in each lake.

  7. 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

  8. Reconstruction of Sea/Lake-Level Changes in an Active Strike-Slip Basin (Gulf of Cariaco, NE Venezuela)

    NASA Astrophysics Data System (ADS)

    van Daele, M.; Audemard, F.; Beck, C.; de Batist, M.; van Welden, A.; Moernaut, J.; 2006 Shipboard Party, G.

    2008-05-01

    In January 2006, 76 high-resolution reflection seismic profiles were acquired in the Gulf of Cariaco, Northeast Venezuela. In the upper 100 m of sedimentary infill, 17 unconformity-bounded sequences were identified and mapped throughout the basin. Up to now, no core or borehole information is available to provide age constraints on these units. The sedimentary infill is cut by several faults, Riedel faults in the central part and the El Pilar fault (one of the main faults of the South American-Caribbean plate boundary) in the southern part of the gulf. The connection of the Gulf of Cariaco with the adjacent Cariaco Basin occurs at a present-day water depth of ~ 55 m. This implies that the gulf was disconnected from the world ocean and functioned as a lake during a large part of the last glacial. The main rivers entering the gulf drain the coastal mountain ranges and tend to form pronounced deltas at their inlet. During times when the gulf was a lake, periods with a dry climate resulted in dramatic lake-level lowstands and even complete desiccation/evaporation. The present-day depths of delta offlap breaks and the presence of lowstand/evaporite deposits can thus be used to estimate sea/lake level at the time of their formation. Detailed analysis of these stratigraphic sea/lake-level indicators allowed reconstructing the sea/lake-level history for the period encompassed by the 17 identified sequences. This sea/lake-level reconstruction also needed to be corrected for tectonic subsidence, affecting different parts of the gulf with different intensity. The reconstructed sea/lake-level curve of the Gulf of Cariaco was compared with the eustatic sea-level curve and with results of previous paleoclimate studies in Venezuela. The striking coherence between the eustatic curve and the amplitudes and absolute heights of successive reconstructed lowstands and highstands compelled us to tune our record to the eustatic curve in order to achieve a rough age estimate for our units

  9. Greigite detected as dominating remanence carrier in Late Pleistocene sediments, Lisan formation, from Lake Kinneret (Sea of Galilee), Israel

    NASA Astrophysics Data System (ADS)

    Ron, H.; Nowaczyk, N. R.; Frank, U.; Schwab, M. J.; Naumann, R.; Striewski, B.; Agnon, A.

    2007-07-01

    A rock magnetic investigation of three sedimentary cores of Lisan formation of late Pleistocene age from Lake Kinneret (Sea of Galilee) northern Israel demonstrates that the magnetization of these sediments is controlled by various degrees of a secondary chemical remanent magnetization (CRM) carried by greigite (Fe3S4). This CRM is superimposed on a primary detrital remanent magnetization (DRM) that resides in Ti-magnetite. This finding is independently confirmed by X-ray diffraction (XRD) measurements performed on magnetic extracts of the sediments. The domain state of the greigite is largely single domain behaviour (SD), thus dominating the magnetization. Therefore, the magnetic record retrieve from of these sediments is not reflecting geomagnetic variations but rather chemical rock magnetic properties, resulting from diagenetic processes. The results of our study suggest that paleomagnetic record of greigite bearing sediments should be interpreted with caution because of the following reasons: 1. Geomagnetic secular variations can be biased, due to large coercivity overlap between magnetite and greigite. 2. Alternating field (AF) demagnetization can produce erroneous directions due to vector distortion by acquisition of a gyro-remnant magnetization (GRM). 3. Estimation of relative paleointensity can be hampered by large-scale variations in natural remnant magnetization (NRM) intensity, caused by the acquisition of a secondary CRM of unknown age and unknown extent superimposed on the DRM. The precipitation of greigite requires reducing conditions at the sediment-water interface and/or interstitial water, associated with the presence of sulphur and iron oxides. Reducing conditions are typical of stratified lakes and other stratified water bodies, such as the Dead Sea, paleo-Lake Lisan, temporarily the Eastern Mediterranean Sea, the Caspian Sea, the Black Sea and many other marine basins. According to our findings, paleomagnetic records from such environments

  10. Massive infestation by Amyloodinium ocellatum (Dinoflagellida) of fish in a highly saline lake, Salton Sea, California, USA.

    PubMed

    Kuperman, B I; Matey, V E

    1999-12-22

    Persistent fish infestation by the parasitic dinoflagellate Amyloodinium ocellatum was found at a highly saline lake, Salton Sea, California, USA. The seasonal dynamics of the infestation of young tilapia was traced in 1997-1998. First appearing in May, it became maximal in June-August, decreased in October and was not detectable in November. Outbreak of the infestation and subsequent mortality of young fish was registered at the Sea at a water temperature and salinity of 40 degrees C and 46 ppt, respectively. Some aspects of the ultrastructure of parasitic trophonts of A. ocellatum and their location on the fish from different size groups are considered. The interactions of parasitological and environmental factors and their combined effect upon fish from the Salton Sea are discussed. PMID:11407406

  11. Development of the Champlain primary care cardiovascular disease prevention and management guideline

    PubMed Central

    Montoya, Lorraine; Liddy, Clare; Hogg, William; Papadakis, Sophia; Dojeiji, Laurie; Russell, Grant; Akbari, Ayub; Pipe, Andrew; Higginson, Lyall

    2011-01-01

    Abstract Problem addressed A well documented gap remains between evidence and practice for clinical practice guidelines in cardiovascular disease (CVD) care. Objective of program As part of the Champlain CVD Prevention Strategy, practitioners in the Champlain District of Ontario launched a large quality-improvement initiative that focused on increasing the uptake in primary care practice settings of clinical guidelines for heart disease, stroke, diabetes, and CVD risk factors. Program description The Champlain Primary Care CVD Prevention and Management Guideline is a desktop resource for primary care clinicians working in the Champlain District. The guideline was developed by more than 45 local experts to summarize the latest evidence-based strategies for CVD prevention and management, as well as to increase awareness of local community-based programs and services. Conclusion Evidence suggests that tailored strategies are important when implementing specific practice guidelines. This article describes the process of creating an integrated clinical guideline for improvement in the delivery of cardiovascular care. PMID:21673196

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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. PMID:24516590

  1. 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

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

    PubMed

    Hadas, Ora; Kaplan, Aaron; Sukenik, Assaf

    2015-02-05

    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.

  3. 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.

  4. 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.

  5. Lake and Sea Populations of Mysis relicta (Crustacea, Mysida) with Different Visual-Pigment Absorbance Spectra Use the Same A1 Chromophore

    PubMed Central

    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. PMID:24516590

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

    USGS Publications Warehouse

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

    2003-01-01

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

  7. 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

  8. A high-resolution diatom-inferred palaeoconductivity and lake level record of the Aral Sea for the last 1600 yr

    NASA Astrophysics Data System (ADS)

    Austin, Patrick; Mackay, Anson; Palagushkina, Olga; Leng, Melanie

    2007-05-01

    Formerly the world's fourth largest lake by area, the Aral Sea is presently undergoing extreme desiccation due to large-scale irrigation strategies implemented in the Soviet era. As part of the INTAS-funded CLIMAN project into Holocene climatic variability and the evolution of human settlement in the Aral Sea basin, fossil diatom assemblages contained within a sediment core obtained from the Aral Sea have been applied to a diatom-based inference model of conductivity ( r2 = 0.767, RMSEP = 0.469 log 10 μS cm - 1). This has provided a high-resolution record of conductivity and lake level change over the last ca. 1600 yr. Three severe episodes of lake level regression are indicated at ca. AD 400, AD 1195-1355 and ca. AD 1780 to the present day. The first two regressions may be linked to the natural diversion of the Amu Darya away from the Aral Sea and the failure of cyclones formed in the Mediterranean to penetrate more continental regions. Human activity, however, and in particular the destruction of irrigation facilities are synchronous with these early regressions and contributed to the severity of the observed low stands.

  9. 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.

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... northeasterly end of Mallets Head to the northeasterly end of Marble Island, and west of a line extending from the northeasterly end of Marble Island to the northeasterly side of Cave Island, and southerly to...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... northeasterly end of Mallets Head to the northeasterly end of Marble Island, and west of a line extending from the northeasterly end of Marble Island to the northeasterly side of Cave Island, and southerly to...

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... northeasterly end of Mallets Head to the northeasterly end of Marble Island, and west of a line extending from the northeasterly end of Marble Island to the northeasterly side of Cave Island, and southerly to...

  13. 33 CFR 110.8 - Lake Champlain, N.Y. and Vt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... northeasterly end of Mallets Head to the northeasterly end of Marble Island, and west of a line extending from the northeasterly end of Marble Island to the northeasterly side of Cave Island, and southerly to...

  14. Near east paleomagnetic secular variation recorded in sediments from the Sea of Galilee (Lake Kinneret)

    NASA Astrophysics Data System (ADS)

    Thompson, R.; Turner, G. M.; Stiller, M.; Kaufman, A.

    1985-03-01

    Paleomagnetic records of declination and inclination from sediments recovered from the bed of Lake Kinneret (32.4°N, 35.7°E) have been dated by radiocarbon techniques. The sediments span the last 5000 yr. The changes in inclination down the sediment cores are more pronounced than the declination fluctuations and are repeatable between the three coring sites, which are several kilometers apart. Magnetic susceptibility logs display 13 maxima in the 5-m-long sequences, with a pronounced susceptibility minimum about 1000 yr B.P. Many of the susceptibility maxima and minima can be easily correlated between coring sites and are shown to be dominantly related to changes in sediment carbonate content. The natural remanent magnetization intensity follows a similar pattern to that of susceptibility, and the natural remanence of the Kinneret sediments is presumed to reside in detrital magnetite grains carried into the lake by the river Jordan from the basalt-rich bedrock of the rift floor and the Golan Heights. The 14C chronology is strongly supported by a pollen study in which pronounced changes in the proportion of olive pollen were interpreted as being due to extensive cultivation of olives around Galilee in the Hellenistic and Byzantine periods. The Kinneret paleosecular variation records, if accurately dated, point to a complex spatial pattern of Holocene secular variation with significant variations over distances as small as 1000-2000 km.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Downstream movement of recently transformed sea lampreys, Petromyzon marinus, in Carp Lake River, Michigan

    USGS Publications Warehouse

    Applegate, Vernon C.; Brynildson, Clifford L.

    1951-01-01

    A total of 7,969 downstream migrants were taken in the 1948–49 season; 16,235 in 1949–50, and 15,103 in 1950–51. Measurements of representative samples from the total catch of sea lamprey migrants of the 1948–49 and 1949–50 seasons revealed a range in length of 95 to 190 millimeters and an average length of 145 millimeters (3.7 to 7.5 inches; mean –5.7 inches).

  20. 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.

  1. Multilevel empirical Bayes modeling for improved estimation of toxicant formulations to suppress parasitic sea lamprey in the upper Great Lakes

    PubMed Central

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

    2011-01-01

    Summary 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 is 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. PMID:21361894

  2. 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.

  3. 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.

  4. Primary producing prokaryotic communities of brine, interface and seawater above the halocline of deep anoxic lake L'Atalante, Eastern Mediterranean Sea.

    PubMed

    Yakimov, Michail M; La Cono, Violetta; Denaro, Renata; D'Auria, Giuseppe; Decembrini, Franco; Timmis, Kenneth N; Golyshin, Peter N; Giuliano, Laura

    2007-12-01

    Meso- and bathypelagic ecosystems represent the most common marine ecological niche on Earth and contain complex communities of microorganisms that are for the most part ecophysiologically poorly characterized. Gradients of physico-chemical factors (for example, depth-related gradients of light, temperature, salinity, nutrients and pressure) constitute major forces shaping ecosystems at activity 'hot spots' on the ocean floor, such as hydrothermal vents, cold seepages and mud volcanoes and hypersaline lakes, though the relationships between community composition, activities and environmental parameters remain largely elusive. We report here results of a detailed study of primary producing microbial communities in the deep Eastern Mediterranean Sea. The brine column of the deep anoxic hypersaline brine lake, L'Atalante, the overlying water column and the brine-seawater interface, were characterized physico- and geochemically, and microbiologically, in terms of their microbial community compositions, functional gene distributions and [(14)C]bicarbonate assimilation activities. The depth distribution of genes encoding the crenarchaeal ammonia monooxygenase alpha subunit (amoA), and the bacterial ribulose-1,5-biphosphate carboxylase/oxygenase large subunit (RuBisCO), was found to coincide with two different types of chemoautotrophy. Meso- and bathypelagic microbial communities were enriched in ammonia-oxidizing Crenarchaeota, whereas the autotrophic community at the oxic/anoxic interface of L'Atalante lake was dominated by Epsilonproteobacteria and sulfur-oxidizing Gammaproteobacteria. These autotrophic microbes are thus the basis of the food webs populating these deep-sea ecosystems. PMID:18059497

  5. 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.

  6. 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

  7. Radium Isotopes as a Proxy for Groundwater Discharge and Residence Time in a Fresh Water Lake: Case Study From the Sea of Galilee, Israel

    NASA Astrophysics Data System (ADS)

    Raanan, H.; Vengosh, A.; Nishri, A.; Paytan, A.

    2006-12-01

    During the past three decades radium isotopes have been extensively used to quantify the extent and the rate of groundwater discharge into coastal and estuarine environments, where fresh groundwater enters a more saline water body. One of the keys for the conservative behavior of radium in saline systems is the inverse dependence of its adsorption on salinity. In fresh groundwater radium is adsorbed, whereas in saline environment, the adsorbed radium is released to the aqueous phase. Here we examine an opposite scenario where saline groundwater discharges to a fresh water lake. We investigated the distribution of the radium isotope quartet in the Sea of Galilee (Cl~230 mg/l) and saline springs (Fuliya springs, Cl~2200 mg/l) that are considered to be the major salt source for the lake. Assuming that the saline springs of Fuliya represent the groundwater discharge to the lake, and that the measured radium activity in the lake is the residual of mixing, radioactive decay, and adsorption to bottom sediments and suspended particles, we conducted mass balance calculations for the different radium isotopes. Since the half-life of ^{226}Ra (1600 y) is higher than the average water residence time (5.8 y), we neglect the decay factor for this isotope. We use the differences in the ^{226}Ra/Cl ratios in the saline source (7.6×10-3) and the lake water (1.8×10-3) to calculate the relative depletion of ^{226}Ra in the lake water. The ^{226}Ra activity in the lake water ("Station A" in the center of the Sea of Galilee; ^{226}Ra=0.44 dmp/l) therefore represents only 24% of the groundwater ^{226}Ra flux, whereas 76% is lost from solution by adsorption. The activities of the short-lived ^{223}Ra (11.6 days) and ^{224}Ra (3.6 days) in the lake (4×10-4 and 5.9×10-3 dpm/l, respectively) represents only 2% and 4%, respectively, of the theoretical activities expected upon dilution. We show that the difference between the ^{224}Ra/^{223}Ra ratios in the lake (15.64) and the saline

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. Lake Superior revisited 1984

    USGS Publications Warehouse

    MacCallum, Wayne R.; Selgeby, James H.

    1987-01-01

    The Lake Superior fish community has changed substantially since the early 1960s, when control of the sea lamprey (Petromyzon marinus) became effective. Self-reproducing stocks of lake trout (Salvelinus namaycush) have been reestablished in many inshore areas, although they have not yet reached pre-sea lamprey abundance; offshore lake trout are probably at or near pre-sea lamprey abundance. Stocks of lake whitefish (Coregonus clupeaformis) appear to have fully recovered; commercial catches are at or above historical levels. Lake herring (Coregonus artedii) are recovering rapidly in U.S. waters and are abundant in western Canadian waters. The population of rainbow smelt (Osmerus mordax), which declined in the 1970s, is recovering. Pacific salmon (Oncorhynchus) are becoming more abundant as a result of increased stocking in U.S. waters and are reproducing in most suitable tributaries; they have become significant in anglers' creels.

  14. [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

  15. [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

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

    SciTech Connect

    Bechtel, S.C.; Mehrtens, C.J. . Geology Dept.)

    1993-03-01

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

  17. Complete genome sequence of 'Halanaeroarchaeum sulfurireducens' M27-SA2, a sulfur-reducing and acetate-oxidizing haloarchaeon from the deep-sea hypersaline anoxic lake Medee.

    PubMed

    Messina, Enzo; Sorokin, Dimitry Y; Kublanov, Ilya V; Toshchakov, Stepan; Lopatina, Anna; Arcadi, Erika; Smedile, Francesco; La Spada, Gina; La Cono, Violetta; Yakimov, Michail M

    2016-01-01

    Strain M27-SA2 was isolated from the deep-sea salt-saturated anoxic lake Medee, which represents one of the most hostile extreme environments on our planet. On the basis of physiological studies and phylogenetic positioning this extremely halophilic euryarchaeon belongs to a novel genus 'Halanaeroarchaeum' within the family Halobacteriaceae. All members of this genus cultivated so far are strict anaerobes using acetate as the sole carbon and energy source and elemental sulfur as electron acceptor. Here we report the complete genome sequence of the strain M27-SA2 which is composed of a 2,129,244-bp chromosome and a 124,256-bp plasmid. This is the second complete genome sequence within the genus Halanaeroarchaeum. We demonstrate that genome of 'Halanaeroarchaeum sulfurireducens' M27-SA2 harbors complete metabolic pathways for acetate and sulfur catabolism and for de novo biosynthesis of 19 amino acids. The genomic analysis also reveals that 'Halanaeroarchaeum sulfurireducens' M27-SA2 harbors two prophage loci and one CRISPR locus, highly similar to that of Kulunda Steppe (Altai, Russia) isolate 'H. sulfurireducens' HSR2(T). The discovery of sulfur-respiring acetate-utilizing haloarchaeon in deep-sea hypersaline anoxic lakes has certain significance for understanding the biogeochemical functioning of these harsh ecosystems, which are incompatible with life for common organisms. Moreover, isolations of Halanaeroarchaeum members from geographically distant salt-saturated sites of different origin suggest a high degree of evolutionary success in their adaptation to this type of extreme biotopes around the world. PMID:27182430

  18. 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

  19. 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

  20. 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.

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

    PubMed

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

    2012-10-01

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

  2. Connecting the Final Drainage of Lake Agassiz to the 8.2 ka Event by Means of a High- Resolution Sea-Level Record From the Mississippi Delta

    NASA Astrophysics Data System (ADS)

    Li, Y.; Tornqvist, T. E.; Nevitt, J. M.; Shen, Z.; Yu, S.

    2008-12-01

    The catastrophic drainage of proglacial lakes Agassiz and Ojibway (LAO) in the early Holocene is widely believed to have triggered the 8.2 ka cold event. The timing of the LAO drainage, however, remains poorly constrained, which impedes our understanding of the abruptness of this climate change in response to a rapid freshwater forcing. Dating of the LAO drainage in the Hudson Bay area (Barber et al., 1999) yielded an age of 8.47 ± 0.30 ka, thus leaving large uncertainties about its connection with the 8.2 ka event. Here we refine the chronology of the final LAO drainage by constructing a high-resolution sea-level record from the Mississippi Delta with the basal peat approach. Two separate basal peat beds are interpreted to bracket an abrupt sea-level rise around 8.2 ka. The stratigraphically deeper level (Level A) contains a 2 cm basal peat layer that is abruptly overlain by Rangia cuneata- bearing lagoonal muds, representing the onset of an abrupt sea-level rise. The stratigraphically shallower level (Level B) contains a 6 cm basal peat layer that is covered by organic-rich muds, representing the end of the abrupt sea-level rise. Radiocarbon dating of different fractions of macrofossils from each peat layer yields consistent ages. The peat layer from Level A and the base of the peat layer from Level B yield ages of 8257 Cal. yr BP (median age with 2 sigma range of 8198-8270) and 8258 Cal. yr BP (median age with 2 sigma range of 8198-8270), respectively. The indistinguishable ages from these two peat layers, together with the diagnostic stratigraphic features, confirms that sea-level rise was likely instantaneous. This new chronology of the final LAO drainage is similar to the timings of the onset of the 8.2 ka event determined from high-resolution studies of Greenland ice cores and an Omani stalagmite, suggesting an instantaneous ocean-atmospheric system response to freshwater forcing, consistent with model predictions.

  3. Where the Lake Meets the Sea: Strong Reproductive Isolation Is Associated with Adaptive Divergence between Lake Resident and Anadromous Three-Spined Sticklebacks

    PubMed Central

    Ravinet, Mark; Hynes, Rosaleen; Poole, Russell; Cross, Tom F.; McGinnity, Phil; Harrod, Chris; Prodöhl, Paulo A.

    2015-01-01

    Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L.) forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean FST = 0.12), we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an important foundation

  4. Where the lake meets the sea: strong reproductive isolation is associated with adaptive divergence between lake resident and anadromous three-spined sticklebacks.

    PubMed

    Ravinet, Mark; Hynes, Rosaleen; Poole, Russell; Cross, Tom F; McGinnity, Phil; Harrod, Chris; Prodöhl, Paulo A

    2015-01-01

    Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L.) forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean FST = 0.12), we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an important foundation

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Microbial Community of a Hydrothermal Mud Vent Underneath the Deep-Sea Anoxic Brine Lake Urania (Eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    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

  10. 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

  11. Head capsule deformities in midge larvae exposed to Burlington Harbor (Lake Champlain) sediments -- field and laboratory investigations

    SciTech Connect

    Lester, D.; Williams, A.; McIntosh, A.; Lacey, R.

    1994-12-31

    Investigations of sediment associated contaminants in Burlington Harbor indicated the harbor contains elevated levels of a number of pollutants. Lead, silver, mercury and total PAH levels exceed NOAA`s ER-M at numerous sites in the harbor. Benzo(a)pyrene concentrations (ranging from 0.055 to 6.64 ug/g (dry wt.)) exceed the ER-M at a number of sites. Pyrene, phenanthrene, fluoranthene, chrysene, anthracene and fluorene also exceed the ER-M at a number of stations within the harbor. Despite these relatively high levels of contaminants found in harbor sediments, solid phase and pore water exposures with Ceriodaphnia dubia indicate acute toxicity at only a limited number of sites. Examination of midge larvae populations from the harbor, however, indicates a high rate of head capsule deformities at some sites. Preliminary work which exposed laboratory cultures of Chironomus tentans to harbor sediment induced a 17% incidence in deformities in the F{sub 1} generation, a 50% incidence in the F{sub 2} generation and a 75% in the F{sub 3} generation. The incidence of deformities decreased substantially when F{sub 3} generation organisms were reared in clean substrate. Laboratory cultures of C. tentans are being exposed to sediments from various harbor sites for determination of head capsule deformity induction. In addition, several generations of larvae will be reared in sediment to determine the overall impacts on survival and whether deformities increase in subsequent generations.

  12. 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...

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

    USGS Publications Warehouse

    Hodges, John W.

    1972-01-01

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

  14. 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.

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

    PubMed Central

    Küpeli, Tülay; Altundağ, Hüseyin; İmamoğlu, Mustafa

    2014-01-01

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

  16. 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.

  17. 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. PMID:19948847

  18. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

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

  19. 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.

  20. 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

  1. 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.

  2. 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.

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

    PubMed

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

    2015-02-01

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

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. 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).

  9. [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. PMID:27169229

  10. 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.

  11. 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)

  12. 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

  13. The Global Climatology of Large Lakes

    NASA Astrophysics Data System (ADS)

    Merchant, Christopher J.; MacCallum, Stuart N.

    2010-12-01

    There are ~250 large lakes in the world, large here meaning lakes with surface areas exceeding 500 km2 . Lakes are potentially sensitive indicators of regional climatic changes and large lakes also significantly modulate climate locally, via their effects on surface atmosphere fluxes and atmospheric stability. The interactions of lakes and atmosphere are therefore significant for climatology and weather forecasting. Relatively few lakes are permanently instrumented (mostly in N America and Europe), and in assimilation systems for numerical weather prediction, highly simplistic approximations for lake surface temperature are giving way to lake temperature models within the land-atmosphere exchange schemes. It is therefore important to exploit satellite observations to inform and constrain lake and weather models, and to provide observations of lake temperature changes for a wider range of lakes. Here we present results from the first phase of an ESA-funded project, ARCLake, to demonstrate accurate lake surface temperatures and detection of ice cover, using ATSR-2 and AATSR, for large lakes globally. It is sometimes assumed that sea surface temperature (SST) techniques are applicable, but in fact, lake-specific approaches are required for cloud detection and for temperature retrieval. In this paper, we present preliminary results from application of the techniques described in a companion paper [1].

  14. Influence of climate changes on the blooms and toxin production of cyanobacteria in the lakes of Latvia (north-eastern Baltic Sea region)

    NASA Astrophysics Data System (ADS)

    Briede, Linda; Barda, Ieva; Purina, Ingrida

    2016-04-01

    Global climate changes have influenced lakes ecosystems resulting in prolonged vegetation season. Long term data shows the earlier warming of water in spring and later cooling in autumn. These modifications are promoting the changes of phytoplankton community from diatom and chrysophytes dominated communities towards cyanobacteria dominated communities. Cyanobacteria are well known as procariotic ancient organisms involved in the production of oxygen, however nowadays they are better known as producers of potent toxins. Long term dynamic of cyanobacterial communities were investigated in lakes Burtnieku and Aluksnes (northern Latvia). Most common cyanobacterial genus were Aphanizomenon, Anabaena, Microcystis, Planktothrix as well as Gloeotrichia known to produce hepatotoxins and neurotoxins. Seasonal toxin production of cyanobacteria was screened using ELISA kits in year 2015. Implications of prolonged cyanobacterial blooms and toxin production on lakes ecosystem are discussed.

  15. 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.

  16. 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.

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

    USGS Publications Warehouse

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

    2003-01-01

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

  18. 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.

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

    USGS Publications Warehouse

    Dryer, William R.; King, George R.

    1968-01-01

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

  20. Lake Eyre

    Atmospheric Science Data Center

    2013-04-16

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

  1. The Wandering Lake

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Great Salt Lake sets record

    NASA Astrophysics Data System (ADS)

    Katzoff, Judith A.

    The level of the Great Salt Lake, Utah, broke its 1873 record on May 12, 1986, rising to 1283.7 m above mean sea level, according to the U.S. Geological Survey (USGS). Heavy snowpack remains in the lake's drainage basin, and the lake is likely to continue rising into June. “It could well go up another foot [i.e., ˜0.3 m],” this season, according to Ted Arnow, USGS district chief in Utah.The Utah state legislature convened a special session on May 13 to discuss measures to control the flooding. Last year, the legislature began to consider funding a plan to pump water from the Great Salt Lake to form a large, shallow pond in the desert 48 km to the west. Because the lake's level was predicted to drop this year, however, the lawmakers postponed action on the issue (Eos, September 10, 1985, p. 641). The Rose Park area of Salt Lake City, which lies below the lake's current level, has been diked, but groundwater is backing up into Rose Park and has to be pumped out over the dikes, Arnow said. Also, trains that use the Southern Pacific railroad causeway, which crosses the lake, have had to be temporarily rerouted south of the lake during storms. The causeway has been progressively raised since 1983, but engineers now say that they can raise it no further because the added weight will make it sink into the lake, Arnow said. If the lake rises much higher, the interstate highway that runs by it might also have to shut down temporarily during storms, he added.

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

    USGS Publications Warehouse

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

    1995-01-01

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

  8. 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.

  9. 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)

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

    article title:  Lake Constance, Europe     View ... This Multi-angle Imaging SpectroRadiometer (MISR) image of Lake Constance covers an area measuring 355 kilometers x 287 kilometers, and ... wastewater and fertilizers. This leads to overproduction of algae and aquatic plants, exhaustion of available oxygen, loss of some fish ...

  16. 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.

  17. 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

  18. SEASAT altimetry for surface height of inland seas

    NASA Technical Reports Server (NTRS)

    Welker, J. E.

    1984-01-01

    The capability of spaceborne altimetry to record the level, or monitor changes in the level, of inland seas was assessed. SEASAT altimetry data from Lake Baikal in Siberia; the Caspian, Black, and Aral Seas in the southern Soviet Union; the Great Salt Lake in the United States; lakes and reservoirs in northwestern and central China; and snow cover in northwestern India and on the Tibetan Plateau were examined.

  19. 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

  20. 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

  1. 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.

  2. Principles of lake sedimentology

    SciTech Connect

    Janasson, L.

    1983-01-01

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

  3. 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

  4. Bubbles in a freshwater lake.

    PubMed

    Thorpe, S A; Stubbs, A R

    1979-05-31

    WHEN the wind is strong enough to produce whitecaps on Loch Ness, patchy 'clouds' of acoustic reflectors are detected well below the surface, the depth to which they penetrate increasing with wind speed (Fig. 1). No seasonal variation in the occurrence of the reflectors has been detected. A biological explanation is therefore discounted and we suggest here that they are bubbles caused by waves breaking and forming whitecaps in deep water. Similar bubble clouds may occur in other lakes and in the sea.

  5. 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. PMID:15162686

  6. Metagenomic Sequencing of Two Salton Sea Microbiomes

    PubMed Central

    Hawley, Erik R.; Schackwitz, Wendy

    2014-01-01

    The Salton Sea is the largest inland body of water in California, with salinities ranging from brackish freshwater to hypersaline. The lake experiences high nutrient input, and its surface water is exposed to temperatures up to 40°C. Here, we report the community profiles associated with surface water from the Salton Sea. PMID:24459270

  7. Metagenomic sequencing of two salton sea microbiomes.

    PubMed

    Hawley, Erik R; Schackwitz, Wendy; Hess, Matthias

    2014-01-01

    The Salton Sea is the largest inland body of water in California, with salinities ranging from brackish freshwater to hypersaline. The lake experiences high nutrient input, and its surface water is exposed to temperatures up to 40°C. Here, we report the community profiles associated with surface water from the Salton Sea. PMID:24459270

  8. 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.

  9. 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

  10. Probable maximum flood at Lake Chippewa near Winter, Wisconsin

    USGS Publications Warehouse

    Krug, William R.

    1976-01-01

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

  11. A survey of lakes in the Republic of Ireland: hydrochemical characteristics and acid sensitivity.

    PubMed

    Aherne, Julian; Kelly-Quinn, Mary; Farrell, Edward P

    2002-09-01

    In 1997, as part of a national program to determine and map critical loads, a lake survey was carried out in the Republic of Ireland. In total 200 lakes were sampled, which represents approximately 3.3% of the total lake population. The majority of lakes were situated in remote, high-altitude, acid-sensitive areas along the coastal margins of the country. Lake chemistry was dominated by marine inputs. Approximately 50% of the lakes had DOC > 5 mg L-1 due to the presence of organic soils in a large proportion of the catchments. Nonmarine sulfate concentrations were at background levels (< 20 mu eq L-1) in 50% of the lakes. Exceedance of critical load was observed in 7% of the sampled lakes (13 lakes). However, there are uncertainties in the critical load calculations due to the interference of sea salts and organic acids; accurate estimation under such conditions requires long-term lake and deposition chemistry.

  12. 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.

  13. 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

  14. 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... application to voyages on the Great Lakes or portions thereof unless specifically provided otherwise in...

  15. 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…

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

    USGS Publications Warehouse

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

    1995-01-01

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

  17. 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.

  18. Astrobiology of Antarctic ice Covered Lakes

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

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

  19. Great Lakes

    USGS Publications Warehouse

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The wild plants and animals and the natural systems that support them in the Great Lakes region are valuable resources of considerable local, regional, and national interest. They are also, in part, transboundary resources that the U.S. shares with its Canadian neighbors to the north. The way these resources are changing over time is inadequately known and is a concern for resource users and for those charged with managing and protecting these unique and valuable resources. This chapter describes the wild plants and animals and the systems that support them in the Great Lakes region; addresses their condition; and points out the gaps in our knowledge about them that, if filled, would aid in their conservation and appropriate use.

  20. 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

  1. A post-Calumet shoreline along southern Lake Michigan

    USGS Publications Warehouse

    Capps, D.K.; Thompson, T.A.; Booth, R.K.

    2007-01-01

    The southern shore of Lake Michigan is the type area for many of ancestral Lake Michigan's late Pleistocene lake phases, but coastal deposits and features of the Algonquin phase of northern Lake Michigan, Lake Huron, and Lake Superior are not recognized in the area. Isostatic rebound models suggest that Algonquin phase deposits should be 100 m or more below modern lake level. A relict shoreline, however, exists along the lakeward margin of the Calumet Beach that was erosional west of Deep River and depositional east of the river. For this post-Calumet shoreline, the elevation of basal foreshore deposits east of Deep River and the base of the scarp west of Deep River indicate a slightly westward dipping water plane that is centered at ???184 m above mean sea level. Basal foreshore elevations also indicate that lake level fell ???2 m during the development of the shoreline. The pooled mean of radiocarbon dates from the surface of the peat below post-Calumet shoreline foreshore deposits indicate that the lake transgressed over the peat at 10,560 ?? 70 years B.P. Pollen assemblages from the peat are consistent with this age. The elevation and age of the post-Calumet shoreline are similar to the Main Algonquin phase of Lake Huron. Recent isostatic rebound models do not adequately address a high-elevation Algonquin-age shoreline along the southern shore of Lake Michigan, but the Goldthwait (1908) hinge-line model does. ?? 2006 Springer Science+Business Media B.V.

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. Aral Sea, Kazakhstan,CIS

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Situated in the middle of an immense desert, much like the Great Salt Lake of Utah, the Aral Sea (45.0N, 59.0E) is landlocked in the center of a broad basin. Rivers flow in but not out; water escapes only by evaporation. In recent years, river water has been diverted for agricultural irrigation and the lake level has fallen 40 to 50 ft., its surface has shrunk by almost 40 % and the salinity has almost tripled. Twenty species of fish are now extinct.

  7. Authigenic carbonate precipitation in Lake Acigöl, a hypersaline lake in southwestern Turkey

    NASA Astrophysics Data System (ADS)

    Balci, Nurgul; Menekse, Meryem; Gül Karagüler, Nevin; Seref Sönmez, M.; Meister, Patrick

    2014-05-01

    Lake Acigöl (Bitter Lake) is a hypersaline lake in southwestern Turkey at an elevation of 836 m above sea level showing authigenic precipitation of several different carbonate mineral phases. It is a perennial lake and closed drainage basin where a semiarid continental climate dominates. Due to the extreme water chemistry (salinity 8-200 mg/l; SO4 112-15232 mg/l; Cl 290-35320 mg/l; Mg, 82-3425 mg/l; Ca 102-745 mg/l) unique microorganisms flourish in the lake. We studied microbial diversity from enrichment cultures and performed precipitation experiments using similar water chemistry and adding bacterial enrichment cultures from lake sediments in order to elucidate whether the mineral assemblages found in the lake can be reproduced. Experiments using moderately halophilic bacteria obtained from the lake sediments demonstrate the formation of various calcium-/magnesium-carbonates: hydromagnesite, dypingite, huntite, monohydrocalcite and aragonite. The relative amounts of different mineral phases, particularly monohydrocalcite, hydromagnesite and dypingite, could be controlled by varying the sulphate concentration in the media from 0 to 56 mM. The similar mineral assemblages identified in the sediments of Lake Acigöl and in the experiments point to similar thermodynamic conditions and kinetics of crystal growth. In particular, the similar spherical morphology points to a rapid crystal growth under strong kinetic inhibition, possibly by organic polymers that are commonly produced by microbial communities. Our results demonstrate that the authigenic carbonate paragenesis of hypersaline lakes as Lake Acigöl can be reproduced in halophilic bacterial cultures. The exact thermodynamic conditions and precipitation kinetics under seasonally changing water chemistry or in batch experiment, however, still have to be constrained in order to establish a microbial model for carbonate precipitation in such environments.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. Longevity of Lake Superior lake trout

    USGS Publications Warehouse

    Schram, Stephen T.; Fabrizio, Mary C.

    1998-01-01

    The age structure of mature lake trout Salvelinus namaycush from the Wisconsin waters of Lake Superior increased following a population recovery that has taken place since the 1960s. As the population aged, it became apparent that scales were unreliable aging structures. Beginning in 1986, we examined both scale and sagittal otolith ages from tagged fish with a known period at liberty. We found large discrepancies in scale and sagittal otolith ages of mature fish, such that scale ages were biased low. We estimated lake trout living up to 42 years, which is greater than previously reported from Lake Superior. Investigators studying lake trout population dynamics in the Great Lakes should be aware that lake trout can live longer than previously thought.

  14. Active Neotectonic Structures in Glacial and Postglacial Sediment in Lake Timiskaming, Timiskaming Graben, Ontario/Quebec Canada

    NASA Astrophysics Data System (ADS)

    Doughty, M.; Eyles, N.; Eyles, C.

    2009-05-01

    The Timiskaming Graben (TG) is a northwest-trending arm of the Ottawa-Bonnechere Graben and the St. Lawrence Rift System (SLRS) in eastern Canada. Together they form a 600 km long failed rift in the Canadian Shield, extending southward along the border of Ontario and Quebec to the St.Lawrence River Valley onto the Hudson Valley and Lake Champlain in the USA. The Timiskaming Graben preserves faulted outliers of Early Paleozoic limestones and has been reactivated several time during the Phanerozoic most recently during the breakup of Pangea. The 110 kilometre-long, ~100 m deep Lake Timiskaming fills the inner part of the Timiskaming Graben along the border of Ontario and Quebec. It is the postglacial successor to glacial Lake Barlow ponded against the northward-retreating Laurentide Ice Sheet some 9,000 years BP. The sedimentary record of Lake Timiskaming was established by collecting more than 1000 line kilometres of high-resolution 'chirp' seismic profiles, side scan and multibeam survey data between 2003 and 2007. These show that bathymetric relief is the product of ongoing tectonic subsidence where lateglacial Barlow glaciolacustrine and postglacial sediments are extensively deformed by closely-spaced horst and grabens. The greatest subsidence has occurred within a narrow (< 3 km) and deep (up to 209 m) central graben basin. We are able to infer the presence of hitherto unrecognized bounding and relay faults within the graben, and a 20 km long 8 m high fault scarp and sand blows produced by large postglacial earthquakes. The region is one of the most seismically active areas in eastern North America (Western Quebec Seismic Zone) with frequent moderate to large magnitude (> M5) intracratonic earthquakes. Structural activity is ongoing along the Timiskaming Graben and its lateglacial and postglacial sediment record provides the clearest evidence to date of modern intracratonic faulting anywhere in eastern North America.

  15. 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

  16. 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.

  17. 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

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

    USGS Publications Warehouse

    U.S. Geological Survey

    1999-01-01

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

  19. Red Sea

    Atmospheric Science Data Center

    2013-04-16

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

  20. 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.

  1. 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.

  2. TALISE: Titan Lake In-situ Sampling Propelled Explorer

    NASA Astrophysics Data System (ADS)

    Urdampilleta, I.; Prieto-Ballesteros, O.; Rebolo, R.; Sancho, J.

    2012-09-01

    Titan is the largest satellite of Saturn System, the only one in the Solar System with a significant atmosphere. About 95% is nitrogen, approximately 3% is methane, and the remaining 2% percent consists of hydrogen, little vapour water, other hydrocarbons, and possibly argon. Hydrocarbons may rain down on the surface, forming enclosed seas, lakes, and ponds. Radar images obtained appear to show lakes of liquid hydrocarbon (such as methane and ethane) in Titan's northern latitudes. The chemical composition of the lakes of Titan is still not well determined. The detection of other compounds and the investigation of influence of both, photochemistry and the atmosphere on the chemical composition of liquids of Titan lakes remain challenging in the absence of in situ measurements. Therefore, it is next step to understand the Titan lakes environment, its relationship with the climate behavior, the surrounding solid substrate and analyze the organic inventory including the possibility of prebiotic compounds.

  3. 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.

  4. 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

    ... TRADES Coastwise Procedure § 4.83 Trade between United States ports on the Great Lakes and other ports of... the Great Lakes via the Hudson River and otherwise than by sea, may operate under a document with a Great Lakes license endorsement and shall not be subject to the requirements for clearance, report...

  5. 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 ...

  6. 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 ...

  7. Status report - Salton Sea solar pond power plant

    SciTech Connect

    French, R.L.; Lin, E.I.H.

    1981-01-01

    The feasibility of constructing salt gradient solar pond commercial power plants in the Salton Sea has been confirmed by a study completed in May 1981. The Salton Sea is an inland salt lake located in the Imperial Valley of Southern California. 600 MW/sub e/ of base load power can be generated if 15% of the sea's 932-km/sup 2/ (360-square mile) surface area is converted to solar ponds. 3 refs.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  9. 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

  10. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

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

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

  11. 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.…

  12. Great Lakes: Chemical Monitoring

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1976-01-01

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

  13. 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…

  14. 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

  15. 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.

  16. 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

  17. Food of lake trout in Lake Superior

    USGS Publications Warehouse

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

    1965-01-01

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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. 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

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

    SciTech Connect

    Andrews, F.L.; Wells, F.C.; Shelby, W.J.; McPherson, E.M.

    1988-01-01

    Lake Austin and Town Lake are impoundments on the Colorado River in Travis County, central Texas, and are a source of water for municipal industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Small vertical temperature variations in both lakes were attributed to shallow depths in the lakes and short retention times of water in the lakes during the summer months. The largest areal variations in dissolved oxygen generally occur in Lake Austin during the summer as a result of releases of water from below the thermocline in Lake Travis. Except for iron, manganese, and mercury, dissolved concentrations of trace elements in water collected from Lake Austin and Town Lake did not exceed the primary or secondary drinking water standards set by the US Environmental Protection Agency. Little or no effect of stormwater runoff on temperature, dissolved oxygen, or minor elements could be detected in either Lake Austin or Town Lake. Little seasonal or areal variation was noted in nitrogen concentrations in Lake Austin or Town lake. Total phosphorus concentrations generally were small in both lakes. Increased concentrations of nitrogen and phosphorus were detected after storm runoff inflow in Town Lake, but not in Lake Austin; densities of fecal-coliform bacteria increased in Lake Austin and Town Lake, but were substantially greater in Town Lake than in Lake Austin. 18 refs., 38 figs., 59 tabs.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Lake Issyk-Kul is located in an intramontane basin of the Tien Shan, Kyrgyzstan, Central Asia, at 1607 m above sea level. It has formed in a tectonically active region with W-E striking major thrust zones both N and S of the lake. The lake is elongated with 180 km in W-E and 60 km in S-N direction and a water depth of roughly 670 m at its central plain. With a surface area of 6232 km2 and a total water colume of around 1736 km3, Lake Issyk-Kul is the second largest lake in the higher altitudes (De Batist et al., 2002). Two large delta areas have formed at the E and W end. Steep slopes at both the N and S shore separate rather narrow, shallow shelf areas from the central deeper plain. First seismic data of lake Issyk-Kul were acquired in 1982 by the Moscow University with a total of 31 profiles across the lake. In 1997 and 2001, a second and third seismic survey of the lake were carried out by the group of Marc De Batist (Ghent, Belgium) in cooperation with the Royal Museum of Central Africa (Tervuren, Belgium) and the SBRAS (Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia) using a sparker system with a single-channel streamer. These surveys were recently completed by a fourth expedition carried out by the University of Bremen in April 2013. During this expedition, 33 additional profiles were acquired with an airgun and a multi-channel streamer. The sparker surveys mostly cover the delta and shelf areas in high detail, while the airgun survey covers the deeper parts of the lake with penetration beyond the first multiple. Bathymetry data reveal that at the delta areas, the shelf is divided into two parts. The shallower comprises the part down to 110 m water depth with an average inclination of 0.5°, while the deeper part reaches from 110 m to 300 m water depth with an average slope inclination of 1°. Incised paleo-river channels of up to 2-3 km width and 50 m depth are visible both on the eastern and western shelf, but are limited to the

  6. 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.

  7. 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.

  8. Stage fluctuations of Wisconsin lakes

    USGS Publications Warehouse

    House, Leo B.

    1985-01-01

    This report describes lake-stage fluctuations of 83 gaged lakes in Wisconsin and presents techniques for estimating stage fluctuation at ungaged lakes. Included are stage information at 83 lakes and stage-frequency data for 32 of these lakes that had sufficient record for analysis. Lakes are classified by a hydrologic-topographic lake classification scheme as ground-water flowthrough (GWF) lakes, surface-water drainage (SWD) lakes, and surface-water flow-through (SWF) lakes. Lakes within the same class were found to have similar water-level fluctuations. The lake-stage records indicate that most annual maximums occur during the months of May and June for all three classes. Annual minimum lake levels generally occur in September for surface-water drainage lakes, in March for surface-water flowthrough lakes, and in November for ground-water flow-through lakes. Data for each lake include location, period of water-level record, hydrologic classification, drainage area, surface area, lake volume, maximum depth, long-term mean stage and its standard deviation, maximum and minimum observed lake stage, and the average annual lake-stage fluctuation.

  9. 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.

  10. Historic Dead Sea Level Fluctuations Calibrated with Geological and Archaeological Evidence

    NASA Astrophysics Data System (ADS)

    Frumkin, Amos; Elitzur, Yoel

    2002-05-01

    The Dead Sea, the Holocene terminal lake of the Jordan River catchment, has fluctuated during its history in response to climatic change. Biblical records, calibrated by radiocarbon-dated geological and archaeological evidence, reinforce and add detail to the chronology of the lake-level fluctuations. There are three historically documented phases of the Dead Sea in the Biblical record: low lake levels ca. 2000-1500 B.C.E. (before common era); high lake levels ca. 1500-1200 B.C.E.; and low lake levels between ca. 1000 and 700 B.C.E. The Biblical evidence indicates that during the dry periods the southern basin of the Dead Sea was completely dry, a fact that was not clear from the geological and archaeological data alone.

  11. 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

  12. 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.

  13. Origins of rainbow smelt in Lake Ontario

    USGS Publications Warehouse

    Bergstedt, Roger A.

    1983-01-01

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

  14. 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

  15. 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.

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

    PubMed

    Payandeh, Jian; Minor, Daniel L

    2015-01-16

    Voltage-gated sodium channels (Na(V)s) provide the initial electrical signal that drives action potential generation in many excitable cells of the brain, heart, and nervous system. For more than 60years, functional studies of Na(V)s 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 (BacNa(V)s) prevalent in soil, marine, and salt lake environments that bear many of the core features of eukaryotic Na(V)s have reframed ideas for voltage-gated channel function, ion selectivity, and pharmacology. Here, we analyze the recent advances, unanswered questions, and potential of BacNa(V)s as templates for drug development efforts.

  17. 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

  18. 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...

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

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

    USGS Publications Warehouse

    Dahl, Frederick H.

    1968-01-01

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

  5. 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.

  6. The future of salmonid communities in the Laurentian Great Lakes

    USGS Publications Warehouse

    Smith, Stanford H.

    1972-01-01

    The effects of human population growth, industrialization, and the introduction of marine fishes have reduced the suitability of each of the Great Lakes for oligotrophic fish communities. The ultimate consequence has been a reduction of fishery productivity that has ranged from extreme in Lake Ontario to moderate in Lake Superior. If measures are not taken to alleviate the adverse effects of marine invaders and trends in environmental quality, a major reduction in fishery productivity can eventually be expected throughout the Great Lakes.Prospects for the next century will be improved if the lakes can be intensively managed. More stringent control of the sea lamprey (Petromyzon marinus), and subsequent reduction of the alewife (Alosa pseudoharengus), by the reestablishment of populations of large piscivores, should permit the recovery of some of the previous predator and prey species, or the development of populations of new species that are more compatible with a reduced number of lampreys. Even if marine species can be reduced greatly, the full restoration of the former fishery productivity remains uncertain and will require a high degree of coordination among all management and research agencies that have responsibilities on the Great Lakes.Unfavorable trends toward progressive degradation of water quality pose the greatest threat to restoration of the fishery resources of the Great Lakes. Where changes in water quality have been the greatest, oligotrophic species have become scarce or absent, and in the deepwater regions no other species have reoccupied the vacated niches.

  7. 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, ...

  8. 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.

  9. 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...

  10. 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.

  11. Ten years of limnological monitoring of a modified natural lake in the tropics: Cote Lake, Costa Rica.

    PubMed

    Umaña, Gerardo

    2014-06-01

    It is located 650m above sea level along the boundary between the North Caribbean and Pacific slopes, near the Southern end of the volcanic Guanacaste mountain range. In the early 1980s the lake's main outlet was dammed and the outflow was diverted into Arenal Reservoir. Lake Cote was first studied in 1990-1991, and later in 2001, before it was again modified by raising its dam by one meter to use its outflow for hydroelectricity. From 2002 to 2010 it has been monitored twice a year for changes in its limnology. Here I present a summary of its basic characteristics and an analysis of their changes through time. The lake is discontinuous polymictic, and sometimes develops a thermocline at 6m depth that may last for several days as evidenced by the occasional development of an anoxic layer close to the bottom. Since its modification for hydropower production, the surface water temperature has attained higher values than before. Oxygen levels in the lake show periods of hypoxia to anoxia in the hypolimnion, that have become more frequent since modification. Despite its turbid water, the lake has low levels of nutrient concentrations and of chlorophyll a. The trend in these parameters in recent times is a reduction in chlorophyll a and an increase in water transparency, implying a reduction in primary productivity. These changes are discussed in relationship with anthropogenic factors such as the modification of the lake and its management, changes in landscape around the lake and global climate change.

  12. 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

  13. 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

  14. 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)

  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. 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.

  17. Utah: Salt Lake City

    Atmospheric Science Data Center

    2014-05-15

    ... backdrops for the 2002 Winter Olympics, to be held in Salt Lake City, Utah. The mountains surrounding Salt Lake City are renowned for ... western edge of the Rocky Mountains and eastern rim of the Great Basin. This early-winter image pair was acquired by the Multi-angle ...

  18. 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.

  19. Great Lakes: Great Gardening.

    ERIC Educational Resources Information Center

    New York Sea Grant Inst., Albany, NY.

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

  20. 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…

  1. Great Lakes Teacher's Guide.

    ERIC Educational Resources Information Center

    Reid, Ron

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

  2. 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

  3. Seismic investigation of Lake Issyk-Kul, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  4. 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.

  5. Lakes and reservoirs

    SciTech Connect

    Taub, F.B.

    1984-01-01

    This volume in the Ecosystems of the World series studies lakes and reservoirs. The book opens with a discussion of the ecosystem processes that are common to all lakes and reservoirs and then proceeds to a description of mathematical models of these processes. The chapters concentrate on lakes and reservoirs in different parts of the world, ranging from polar to tropical lakes, and in many of the chapters the effects of human activities such as dam construction, increased nutrient inputs, toxic contaminants and fish introduction, are also considered. The book concludes with a summary of the efforts at lake restoration that are being undertaken in many communities in an attempt to undo the damage that has resulted from some of these activities.

  6. 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.

  7. Spatial patterns in PCB concentrations of Lake Michigan lake trout

    USGS Publications Warehouse

    Madenjian, Charles P.; DeSorcie, Timothy J.; Stedman, Ralph M.; Brown, Edward H.; Eck, Gary W.; Schmidt, Larry J.; Hesselberg, Robert J.; Chernyak, Sergei M.; Passino-Reader, Dora R.

    1999-01-01

    Most of the PCB body burden in lake trout (Salvelinus namaycush) of the Great Lakes is from their food. PCB concentrations were determined in lake trout from three different locations in Lake Michigan during 1994–1995, and lake trout diets were analyzed at all three locations. The PCB concentrations were also determined in alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), slimy sculpin (Cottus cognatus), and deepwater sculpin (Myoxocephalus thompsoni), five species of prey fish eaten by lake trout in Lake Michigan, at three nearshore sites in the lake. Despite the lack of significant differences in the PCB concentrations of alewife, rainbow smelt, bloater, slimy sculpin, and deepwater sculpin from the southeastern nearshore site near Saugatuck (Michigan) compared with the corresponding PCB concentrations from the northwestern nearshore site near Sturgeon Bay (Wisconsin), PCB concentrations in lake trout at Saugatuck were significantly higher than those at Sturgeon Bay. The difference in the lake trout PCB concentrations between Saugatuck and Sturgeon Bay could be explained by diet differences. The diet of lake trout at Saugatuck was more concentrated in PCBs than the diet of Sturgeon Bay lake trout, and therefore lake trout at Saugatuck were more contaminated in PCBs than Sturgeon Bay lake trout. These findings were useful in interpreting the long-term monitoring series for contaminants in lake trout at both Saugatuck and the Wisconsin side of the lake.

  8. 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.

  9. Evidence of offshore lake trout reproduction in Lake Huron

    USGS Publications Warehouse

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

    2003-01-01

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

  10. 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.

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

    USGS Publications Warehouse

    Carl, Leon M.; McGuiness, Fiona

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Shentsis, Izabela; Rosenthal, Eliyahu; Magri, Fabien

    2014-05-01

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Epidemiology of Great Lakes bald eagles.

    PubMed

    Colborn, T

    1991-08-01

    Historical data are provided to support the hypothesis that organochlorine chemicals introduced into the Great Lakes ecosystem following World War II are the cause of reproductive loss among bald eagles (Haliaeetus leucocephalus) in the basin. This is supported with data on concurrent population fluxes of extrabasin North American bald eagle populations and the European white-tailed sea eagle (Haliaeetus albicillus) where the same chemicals were produced and released. Organochlorine chemicals appear as a unique stress on Great Lakes bald eagle populations when compared with stresses on successful populations of bald eagles continentwide. Shoreline birds bear significantly higher concentrations of these persistent toxics than inland birds. Association between contaminated prey and elevated concentrations of PCBs, DDT, and DDE in Great Lakes bald eagles are presented. A fledging ratio is used to support the hypothesis that maternal prezygotic exposure affects the viability of embryos and chicks. The ratio of the mean number of fledglings per successful territory to the mean number of fledglings per active territory, when the numerator is greater than 1.4, provides an index of exposure to contaminants by parental animals and affected offspring. When the ratio is greater than 2, parental exposure to organochlorine chemicals should be considered. The adverse effects of prezygotic exposure to the same contaminants in other animal species dependent upon Great Lakes fish, and extrabasin bald eagle populations dependent upon contaminated fish, provide consistency to the argument. The mechanism of action of the organochlorine chemicals further strengthens the causal argument indicting DDT, DDE, and PCBs. A strong association between DDT/DDE and bald eagle reproductive success is provided. However, the role of PCBs is not ruled out. Only data for total PCB concentrations in bald eagle tissue are available, and until specific PCB congeners are quantified there will be

  18. Analysis of lake-air heat and water transfer processes in a high-altitude shallow lake on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Binbin; Ma, Yaoming; Su, Bob; Chen, Xuelong; Ma, Weiqiang; Menenti, Massimo

    2016-04-01

    With an estimated 32,843 total lakes on the Tibetan Plateau, lakes play an important role in the water cycle and energy budget of the "Third Pole" area. Due to a lack of observational data and adequate modelling systems, lake-air momentum, heat and water vapour transfer process is poorly understood for high-altitude lakes on the Tibetan Plateau. By using eddy covariance observation data in a high-altitude shallow small lake from April 2012 to October 2014, lake-air energy and mass transfer process is carefully analysed and simulated. Our main findings are as follows: (1), our observations are dominated by unstable and near neutral atmosphere conditions, corresponding to the observed large temperature gradients and strong winds;(2), the bulk transfer coefficient and roughness length for water are higher than those for heat, and free convection gives a square root dependence of latent heat flux on wind speed; (3), the influencing factors for latent heat flux and sensible heat flux under different atmosphere stability is different; (4), the shape of the lake can influence the roughness length for momentum through the difference in its lake depth or fetch length;(5) the commonly-used roughness length for momentum with sea parameters will cause an underestimation of lake-air latent and sensible heat flux simulation, and the appropriate Charnock coefficient and roughness Reynolds number are estimated to be 0.031 and 0.54, respectively, by our observation.

  19. 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.

  20. 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.

  1. Yellowstone Lake Nanoarchaeota

    PubMed Central

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

    2013-01-01

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

  2. 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.

  3. 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.

  4. 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.

  5. Lake Enriquillo Water Level History and Implications for future flooding in the Southwestern Dominican Republic

    NASA Astrophysics Data System (ADS)

    Wright, V. D.; Hornbach, M. J.; McHugh, C. M.; Asilis, Y.; Montes, M.

    2013-12-01

    Lake Enriquillo is currently located -41m below sea-level, and is the largest lake (~350 km2) in the Caribbean. Lake levels during the past eight years have risen to anomalous highs (from -51m BSL to -41m BSL), flooding villages and displacing their inhabitants. Both the cause of lake level rise and the anticipated future change in lake level remain unclear. Seismic images revealing erosional and depositional sedimentary boundaries in the lake, however, provide insight into historic lake level trends. Here, we integrate seismic images with sediment core samples, and historical photographs to constrain lake level history with time. We used ASTER global digital elevation models combined with single beam data to determine the lake's bathymetry, drainage and surrounding geomorphology. Additionally, we used NOAA and local weather station data to assess the potential role that weather and climate patterns play in lake levels. Although yearly weather conditions play a major role in lake levels, analysis of regional seismic data indicates that tectonics may also play an important role in longer term (century-scale) lake levels. The lake's areal extent and lake level elevation depend not only on the water supply, but also the lake's bathymetry and regional topography that is defined by the Enriquillo-Plantain Garden Fault--a strike-slip fault system that extends throughout the lake. The shallow bathymetry of much of the lake (~ 20%) implies that relatively small changes in the rain pattern cause significant (10 m) changes to lake depth. Over the past thirty years, variations in the lake's areal extent (between 160 km2 to 350km2) and elevation (between -52m BSL to -41m BSL) can be attributed to changes in weather patterns. Preliminary analysis of both core and seismic data confirm that the lake water levels generally mimic wet and dry periods in the region, consistent with recent observations, however, the longer term maximum and minimum extent of Lake Enriquillo water

  6. 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.

  7. 15 CFR 918.5 - Eligibility, qualifications, and responsibilities-Sea Grant Regional Consortia.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-State approach to solving problems or meeting needs relating to ocean, Great Lakes, and coastal... above as evaluated by a site review team composed of members of the Sea Grant Review Panel, the Office... Regional Consortium candidate's Sea Grant Program must be relevant to regional opportunities and...

  8. Effect of Nasser Lake on Gravity Reduction and Geoid Computation

    NASA Astrophysics Data System (ADS)

    Abd-Elmotaal, Hussein; Makhloof, Atef; Hassan, Ayman; Ashry, Mostafa

    2016-04-01

    The determination of the gravimetric geoid is based on the magnitude of gravity observed at the topographic surface of the earth. In order to satisfy Laplace's equation, the masses between the surface of the earth and the geoid must be removed or shifted inside the geoid. Then the gravity values have to be reduced to the geoid, forming the boundary values on the boundary surface. Gravity reduction techniques usually presume that positive elevations are reserved for positive topography. In case of lake Nasser, the whole lake with its bed floor is above sea level, i.e., having positive elevation. This leads to an obvious error in the topographic reduction using, for example, TC program by assuming rock topography filling the lake instead of water. The aim of this paper is to determine the effect of Nasser lake on gravity reduction and geoid computation in Egypt, as a prototype of the effect of great lakes on gravity reduction and geoid determination. The results proved that Nasser lake, having relatively shallow depths up to 25 m, has a minor effect on both the gravity anomalies and the geoidal heights in Egypt.

  9. Thermokarst lake waters across the permafrost zones of western Siberia

    NASA Astrophysics Data System (ADS)

    Manasypov, R. M.; Pokrovsky, O. S.; Kirpotin, S. N.; Shirokova, L. S.

    2014-07-01

    This work describes the hydrochemical composition of thermokarst lake and pond ecosystems, which are observed in various sizes with different degrees of permafrost influence and are located in the northern part of western Siberia within the continuous and discontinuous permafrost zones. We analysed the elemental chemical composition of the lake waters relative to their surface areas (from 10 to 106 m2) and described the elemental composition of the thermokarst water body ecosystems in detail. We revealed significant correlations between the Fe, Al, dissolved organic carbon (DOC) and various chemical elements across a latitude gradient covering approximately 900 km. Several groups of chemical elements that reflect the evolution of the studied water bodies were distinguished. Combining the data for the studied latitude profile with the information available in the current literature demonstrated that the average dissolved elemental concentrations in lakes with different areas depend specifically on the latitudinal position, which is presumably linked to (1) the elements leached from frozen peat, which is the main source of the solutes in thermokarst lakes, (2) marine atmospheric aerosol depositions, particularly near the sea border and (3) short-range industrial pollution by certain metals from the largest Russian Arctic smelter. We discuss the evolution of the chemical compositions observed in thermokarst lakes during their formation and drainage and predict the effect that changing the permafrost regime in western Siberia has on the hydrochemistry of the lakes.

  10. 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.

  11. 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.

  12. 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.

  13. Ross Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  Icebergs in the Ross Sea     View Larger Image Two large icebergs, designated B-15A and C-16, are captured in this Multi-angle Imaging ... the longitudinal quadrant in which it is first seen, and new icebergs sighted in that quadrant are sequentially numbered. B-15 divided from ...

  14. Aral Sea

    Atmospheric Science Data Center

    2013-04-16

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

  15. 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

  16. 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

  17. 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...

  18. 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.

  19. 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

  20. Lake Superior, Duluth, MN

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  1. 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.

  2. Association between winter precipitation and water level fluctuations in the Great Lakes and atmospheric circulation patterns

    SciTech Connect

    Rodionov, S.N.

    1994-11-01

    Atmospheric precipitation in the Great Lakes basin, as a major mediating variable between atmospheric circulation and lake levels, is analyzed relative to both. The effect of cumulative winter precipitation on lake levels varies from lake to lake and depends on both the state of the lake level itself and air temperature. For periods with a quasi-stable temperature regime, the correlation coefficient between winter precipitation and changes in lake levels from November to spring months reaches 0.8. An analysis of composite maps of mean winter 700-mb heights and sea level pressure for the years with well-above and well-below normal precipitation in the lower Great Lakes basin (Lakes Michigan-Huron, St. Clair, Erie, and Ontario) has shown that changes in precipitation are associated with the wave train structure in the lower and midtroposphere that is similar to the Pacific/North American (PNA) teleconnection pattern. During the positive phase of the PNA-like pattern, when the upper-atmospheric ridge/trough system is amplified, cyclones passing over the Great Lakes basin are frequently of Alberta (Canada) origin and carry relatively small amounts of precipitation. As a result, lake levels tend to decline. On the contrary, during the negative phase of the pattern when the atmospheric circulation is more zonal, the main storm track is oriented from the southwest to the northeast and cyclones bring enough precipitation to induce a rise in lake levels. The effect of the position of the upper-atmospheric trough over the east coast of North America on the precipitation regime in the Great Lakes basin is also demonstrated. 42 refs., 11 figs., 4 tabs.

  3. Salting our Freshwater: A Macrosystems Study of Global Chloride Patterns and Trends in Lakes

    NASA Astrophysics Data System (ADS)

    Dugan, H.; Bartlett, S.; Burke, S.; Doubek, J.; Krivak-Tetley, F.; Skaff, N.; Summers, J.; Farrell, K.; McCullough, I.; Morales, A. M.; Roberts, D.; Yang, Z.; Scordo, F.; Hanson, P. C.; Weathers, K. C.

    2015-12-01

    Chloride is a naturally occurring ion in freshwater lakes that can have adverse ecological impacts if concentrations rise above natural background levels. Many lakes worldwide, including the Great Lakes, have seen increased chloride concentrations over the past few decades. Regional drivers include both natural processes (e.g., sea salt deposition and long periods of drought) and anthropogenic influences (e.g., runoff from road salt application and agricultural fertilizer and discharge of industrial effluent). While these trends and drivers have been studied at the watershed scale, there has been no large-scale analyses of chloride trends in freshwater lakes. Here, we have compiled a dataset of long-term (> 10 years) chloride concentrations in over 500 freshwater lakes, ponds and reservoirs worldwide (>0.04 ha), predominantly in the United States, Canada, Sweden, and the United Kingdom. The geographic and morphometric range of lakes in this dataset allows us to assess the impact of ecoregion, lake area, residence time, and lake depth on relative changes in chloride concentrations. For the United States, we combined our dataset with the National Land Cover Database and the National Hydrography Dataset to quantify percent impervious surface, as a proxy for road density, within the near-shore environment of our study lakes. We find that urban lakes, especially in the American Midwest (Wisconsin, Minnesota) have strong positive trends in chloride concentrations, whereas remote lakes, such as ponds in the Adirondack Mountains of New York, have had stable or decreasing chloride levels. In states with seasonal road-salt application, the percent impervious surface within 100 m of a lake is strongly correlated with increases in chloride. Road salt runoff is just one ecological threat to urban lakes, but can be abated with proper management.

  4. Overview: Ancient Lake Creede

    USGS Publications Warehouse

    Bethke, Philip M.; Hay, Richard L.

    2000-01-01

    Lake Creede was moderately saline closed-basin lake that developed in the 26.9 Ma Creede caldera in the San Juan Mountains in the southwest Colorado. The volcaniclastic sediments deposited within the late Oligocene lake were first described and named as the Creede Formation by Emmons and Larsen (1923). The lake and its sedimentary fill are of interest first as representatives of a caldera-hosted lake in a silicic volcanic terrane, and second because of the likely involvement of lake fluids or related pore waters in the deposition of the 25 Ma silver and base-metal ores of the Creede mining district north of the Creede caldera (Fig. 1), as proposed Bethke and Rye (1979). Much of the material presented in this volume is based on observation of core samples and on downhole geophysical measurements obtained as part of a U.S. Continental Scientific Drilling Program in the moat of the Creede caldera. These core and downhole studies are supplemented by outcrop studies, some initiated in support of the drilling program (Bethke and Lipman, 1987), and by conceptual studies of the evolution of the Creede caldera and its surrounding landscape. Not surprisingly, not all authors agree on all interpretation. Most disagreements are pointed out in this overview chapter, and may present opportunities for future study.

  5. 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"…

  6. 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

  7. Arctic epishelf lakes as sentinel ecosystems: Past, present and future

    NASA Astrophysics Data System (ADS)

    Veillette, Julie; Mueller, Derek R.; Antoniades, Dermot; Vincent, Warwick F.

    2008-12-01

    Ice shelves are a prominent but diminishing feature of the northern coastline of Ellesmere Island in the Canadian High Arctic (latitude 82-83°N). By blocking embayments and fiords, this thick coastal ice can create epishelf lakes, which are characterized by a perennially ice-capped water column of freshwater overlying seawater. The goal of this study was to synthesize new, archived, and published data on Arctic epishelf lakes in the context of climate change. Long-term changes along this coastline were evaluated using historical reports, cartographic analysis, RADARSAT imagery, and field measurements. These data, including salinity-temperature profiling records from Disraeli Fiord spanning 54 years, show the rapid decline and near disappearance of this lake type in the Arctic. Salinity-temperature profiling of Milne Fiord, currently blocked by the Milne Ice Shelf, confirmed that it contained an epishelf lake composed of a 16-m thick freshwater layer overlying seawater. A profiling survey along the coast showed that there was a continuum of ice-dammed lakes from shallow systems dammed by multiyear landfast sea ice to deep epishelf lakes behind ice shelves. The climate warming recently observed in this region likely contributed to the decline of epishelf lakes over the last century, and the air temperature trend predicted for the Arctic over the next several decades implies the imminent loss of this ecosystem type. Our results underscore the distinctive properties of coastal ice-dammed lakes and their value as sentinel ecosystems for the monitoring of regional and global climate change.

  8. 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

  9. 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.

  10. 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. PMID:19252888

  11. 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.

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

    USGS Publications Warehouse

    Edsall, Thomas A.; Kennedy, Gregory W.

    1995-01-01

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

  13. 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

  14. 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.

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

    USGS Publications Warehouse

    Piavis, George W.; Howell, John H.

    1969-01-01

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

  16. 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.

  17. Bottom-up versus top-down effects on ciliate community composition in four eutrophic lakes (China).

    PubMed

    Li, Jing; Chen, Feizhou; Liu, Zhengwen; Zhao, Xiuxia; Yang, Kun; Lu, Wenxuan; Cui, Kai

    2016-04-01

    Previous studies have shown that ciliate plankton is generally controlled by food resources (e.g., algae) and predators (e.g., metazooplankton). Among lakes with similar trophic levels but different distributions of phyto- and metazooplankton, the main forces acting on ciliate assemblages may be different. We investigated the relationship between ciliate communities and bottom-up versus top-down variables based on a survey of four subtropical eutrophic lakes (China). Two of the lakes (Chaohu, Taihu) are located on the Mid-lower Yangtze Plain near sea level, and the other two (Dianchi, Xingyunhu) on the Yunnan-Kweichow Plateau at 1700 m above sea level. Blooms of cyanobacteria developed during summer in Lakes Chaohu and Taihu and throughout the year in Lakes Dianchi and Xingyunhu. Ciliate functional feeding groups differed significantly between lakes. The results of canonical correspondence analysis (CCA) and variation partitioning showed that cyanobacteria significantly influence ciliate species, whereas 'edible' algae (cryptophytes, diatoms) and cladocerans were the important variables in explaining the ciliate community structure of Lakes Dianchi and Xingyunhu compared with Lakes Taihu and Chaohu. Our results highlight the importance of consistent cyanobacterial blooms in shaping the ciliate community in subtropical eutrophic shallow lakes by interacting with top-down and bottom-up factors.

  18. 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.

  19. 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.

  20. Recent mass invasion of the North American Great Lakes by Ponto-Caspian species.

    PubMed

    Ricciardi; MacIsaac

    2000-02-01

    The North American Great Lakes have been invaded and dramatically altered by more than 145 alien species. Many invasions have occurred during the past few decades because of the release of Eurasian ballast water from transoceanic ships. Current regulations require ships to exchange foreign ballast with highly saline water before entering the Great Lakes; this procedure should prevent colonization by strictly freshwater species, but species with broad salinity tolerance might survive transport in exchanged water. A recent series of invasions by euryhaline organisms from the Black and Caspian Seas region signals a new phase in the transformation of the Great Lakes - one that supports the concept of an 'invasional meltdown'.

  1. Evidence of lake whitefish spawning in the Detroit River: Implications for habitat and population recovery

    USGS Publications Warehouse

    Roseman, E.F.; Kennedy, G.W.; Boase, J.; Manny, B.A.; Todd, T.N.; Stott, W.

    2007-01-01

    Historic reports imply that the lower Detroit River was once a prolific spawning area for lake whitefish (Coregonus clupeaformis) prior to the construction of the Livingstone shipping channel in 1911. Large numbers of lake whitefish migrated into the river in fall where they spawned on expansive limestone bedrock and gravel bars. Lake whitefish were harvested in the river during this time by commercial fisheries and for fish culture operations. The last reported landing of lake whitefish from the Detroit River was in 1925. Loss of suitable spawning habitat during the construction of the shipping channels as well as the effects of over-fishing, sea lamprey (Petromyzon marinus) predation, loss of riparian wetlands, and other perturbations to riverine habitat are associated with the disappearance of lake whitefish spawning runs. Because lake whitefish are recovering in Lake Erie with substantial spawning occurring in the western basin, we suspected they may once again be using the Detroit River to spawn. We sampled in the Detroit River for lake whitefish adults and eggs in late fall of 2005 and for lake whitefish eggs and fish larvae in 2006 to assess the extent of reproduction in the river. A spawning-ready male lake whitefish was collected in gillnets and several dozen viable lake whitefish eggs were collected with a pump in the Detroit River in November and December 2005. No lake whitefish eggs were found at lower river sites in March of 2006, but viable lake whitefish eggs were found at Belle Isle in the upper river in early April. Several hundred lake whitefish larvae were collected in the river during March through early May 2006. Peak larval densities (30 fish/1,000 m3 of water) were observed during the week of 3 April. Because high numbers of lake whitefish larvae were collected from mid- and downstream sample sites in the river, we believe that production of lake whitefish in the Detroit River may be a substantial contribution to the lake whitefish population

  2. 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.

  3. Movements of adult lake trout in Lake Superior

    USGS Publications Warehouse

    Rahrer, Jerold F.

    1968-01-01

    Returns from mature lake trout (Salvelinus namaycush) tagged in western Lake Superior in 1959 and 1962-65 described here suggest that trout disperse widely from the spawning grounds after spawning and return in subsequent years. Although the data were not extensive, returns from lake trout tagged near Keweenaw Point in 1950 and off Marquette, Michigan, in 1952 suggested similar movement. Loftus stated that river-spawning lake trout of eastern Lake Superior returned annually to the same spawning streams. Movements of lake trout must be understood to manage and evaluate the rehabilitation of lake trout stocks in Lake Superior, especially when the trout move across interstate and international boundaries and are subject to different fishing regulations and fishing pressures.

  4. 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.

  5. Development of sea lamprey (Petromyzon marinus) larvicides

    USGS Publications Warehouse

    Howell, John H.; Lech, John J.; Allen, John L.

    1980-01-01

    Larvicides are used to control sea lamprey (Petromyzon marinus) in the Great Lakes. These larvicides are useful because they are more toxic to sea lamprey than fish species found in the same habitat. The lampricides come from two classes of chemical compounds: (1) halonitrophenols, and (2) halonitrosalicylanilides. Selectivity of the larvicides appears to be based on the differences in the ability of sea lamprey larvae and fishes to detoxify and/or excrete the chemicals. Glucuronide conjugation is an important mechanism for detoxification of these larvicides by fish, and selectivity of larvicides may be due to differences in glucuronyl transferase activity between lamprey and fishes. If more detailed information were available on uptake, metabolism, excretion, and the biochemistry and physiology of lamprey as compared to fishes, it might be possible to design chemicals that would be more selective than those now in use.

  6. Assessing occupational exposure to sea lamprey pesticides

    PubMed Central

    Ceballos, Diana M; Beaucham, Catherine C; Kurtz, Kristine; Musolin, Kristin

    2015-01-01

    Background: Sea lampreys are parasitic fish found in lakes of the United States and Canada. Sea lamprey is controlled through manual application of the pesticides 3-trifluoromethyl-4-nitrophenol (TFM) and BayluscideTM into streams and tributaries. 3-Trifluoromethyl-4-nitrophenol may cause irritation and central nervous system depression and Bayluscide may cause irritation, dermatitis, blisters, cracking, edema, and allergic skin reactions. Objectives: To assess occupational exposures to sea lamprey pesticides. Methods: We developed a wipe method for evaluating surface and skin contamination with these pesticides. This method was field tested at a biological field station and at a pesticide river application. We also evaluated exposures using control banding tools. Results: We verified TFM surface contamination at the biological station. At the river application, we found surfaces and worker’s skin contaminated with pesticides. Conclusion: We recommended minimizing exposures by implementing engineering controls and improved use of personal protective equipment. PMID:25730600

  7. 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.

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

    PubMed

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

    2013-06-01

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

  9. 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...

  10. 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

  11. Wave characteristics in Lake Peipsi

    NASA Astrophysics Data System (ADS)

    Nikolkina, Irina; Soomere, Tarmo; Didenkulova, Ira

    2013-04-01

    The main features of wave properties in relatively large but shallow Lake Peipsi (Estonia/Russia) are determined based on wave measurements at its western coast (58.75°N 27.1°E) in summer and autumn 2005-2007. Although the data set is relatively limited, it still covers 263 days and characterizes well the basic properties of wave climate in this water body. The wave regime is mostly calm, with the long-term average significant wave height below 0.3 m and seas with Hs <0.2 m covering at least 2/3 of the ice-free time. The seasonal variation in wave properties mimics the analogous variation in the wind speed, with the most stormy months October-December. Wave heights are, on average, considerably lower in summer (July-August) than in autumn (October-November). Significant wave heights >1 m were recorded in autumn and covered 3% or the measurement time. The maximum recorded wave height Hs = 1.98 m occurred on October 27, 2005. The mean periods are mostly concentrated in a range of 1.5-2.5 s and exhibit an almost Gaussian distribution.

  12. 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

  13. 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...

  14. 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...

  15. Evidence for lack of homing by sea lampreys

    USGS Publications Warehouse

    Bergstedt, Roger A.; Seelye, James G.

    1995-01-01

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

  16. 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.

  17. 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 Bl

  18. 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. PMID:27104923

  19. 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 l