Sample records for assessment lake ontario

  1. Lake Ontario benthic prey fish assessment, 2015 (United States)

    Weidel, Brian C.; Walsh, M.G.; Holden, J. P.; Connerton, M.J.


    Benthic prey fishes are a critical component of the Lake Ontario food web, serving as energy vectors from benthic invertebrates to native and introduced piscivores. Since the late 1970’s, Lake Ontario benthic prey fish status was primarily assessed using bottom trawl observations confined to the lake’s south shore, in waters from 8 – 150 m (26 – 492 ft). In 2015, the Benthic Prey Fish Survey was cooperatively adjusted and expanded to address resource management information needs including lake-wide benthic prey fish population dynamics. Effort increased from 55 bottom trawl sites to 135 trawl sites collected in depths from 8 - 225m (26 – 738 ft). The spatial coverage of sampling was also expanded and occurred in all major lake basins. The resulting distribution of tow depths more closely matched the available lake depth distribution. The additional effort illustrated how previous surveys were underestimating lake-wide Deepwater Sculpin, Myoxocephalus thompsonii, abundance by not sampling in areas of highest density. We also found species richness was greater in the new sampling sites relative to the historic sites with 11 new fish species caught in the new sites including juvenile Round Whitefish, Prosopium cylindraceum, and Mottled sculpin, Cottus bairdii. Species-specific assessments found Slimy Sculpin, Cottus cognatus abundance increased slightly in 2015 relative to 2014, while Deepwater Sculpin and Round Goby, Neogobius melanostomus, dramatically increased in 2015, relative to 2014. The cooperative, lake-wide Benthic Prey Fish Survey expanded our understanding of benthic fish population dynamics and habitat use in Lake Ontario. This survey’s data and interpretations influence international resource management decision making, such as informing the Deepwater Sculpin conservation status and assessing the balance between sport fish consumption and prey fish populations. Additionally a significant Lake Ontario event occurred in May 2015 when a single

  2. Benthic prey fish assessment, Lake Ontario 2013 (United States)

    Weidel, Brian C.; Walsh, Maureen; Connerton, Michael J.


    The 2013 benthic fish assessment was delayed and shortened as a result of the U.S. Government shutdown, however the assessment collected 51 of the 62 planned bottom trawls. Over the past 34 years, Slimy Sculpin abundance in Lake Ontario has fluctuated, but ultimately decreased by two orders of magnitude, with a substantial decline occurring in the past 10 years. The 2013 Slimy Sculpin mean bottom trawl catch density (0.001 ind.·m-2, s.d.= 0.0017, n = 52) and mean biomass density (0.015 g·m-2 , s.d.= 0.038, n = 52) were the lowest recorded in the 27 years of sampling using the original bottom trawl design. From 2011-2013, the Slimy Sculpin density and biomass density has decreased by approximately 50% each year. Spring bottom trawl catches illustrate Slimy Sculpin and Round Goby Neogobius melanostoma winter habitat overlaps for as much as 7 months out of a year, providing opportunities for competition and predation. Invasive species, salmonid piscivory, and declines in native benthic invertebrates are likely all important drivers of Slimy Sculpin population dynamics in Lake Ontario. Deepwater Sculpin Myoxocephalus thompsonii, considered rare or absent from Lake Ontario for 30 years, have generally increased over the past eight years. For the first time since they were caught in this assessment, Deepwater Sculpin density and biomass density estimates declined from the previous year. The 2013 abundance and density estimates for trawls covering the standard depths from 60m to 150m was 0.0001 fish per square meter and 0.0028 grams per square meter. In 2013, very few small (Lake Ontario spring Alewife assessment in 2002. Since that assessment, observations indicate their population has expanded and they are now found along the entire south shore of Lake Ontario, with the highest densities in U.S. waters just east of the Niagara River confluence. In the 2013 spring-based assessment, both the abundance and weight indices increased slightly as compared to 2012. The number

  3. Integrated ecosystem assessment: Lake Ontario water management.

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    Mark B Bain

    Full Text Available BACKGROUND: Ecosystem management requires organizing, synthesizing, and projecting information at a large scale while simultaneously addressing public interests, dynamic ecological properties, and a continuum of physicochemical conditions. We compared the impacts of seven water level management plans for Lake Ontario on a set of environmental attributes of public relevance. METHODOLOGY AND FINDINGS: Our assessment method was developed with a set of established impact assessment tools (checklists, classifications, matrices, simulations, representative taxa, and performance relations and the concept of archetypal geomorphic shoreline classes. We considered each environmental attribute and shoreline class in its typical and essential form and predicted how water level change would interact with defining properties. The analysis indicated that about half the shoreline of Lake Ontario is potentially sensitive to water level change with a small portion being highly sensitive. The current water management plan may be best for maintaining the environmental resources. In contrast, a natural water regime plan designed for greatest environmental benefits most often had adverse impacts, impacted most shoreline classes, and the largest portion of the lake coast. Plans that balanced multiple objectives and avoided hydrologic extremes were found to be similar relative to the environment, low on adverse impacts, and had many minor impacts across many shoreline classes. SIGNIFICANCE: The Lake Ontario ecosystem assessment provided information that can inform decisions about water management and the environment. No approach and set of methods will perfectly and unarguably accomplish integrated ecosystem assessment. For managing water levels in Lake Ontario, we found that there are no uniformly good and bad options for environmental conservation. The scientific challenge was selecting a set of tools and practices to present broad, relevant, unbiased, and accessible

  4. Bathymetry of Lake Ontario (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  5. Assessing diet compositions of Lake Ontario predators using fatty acid profiles of prey fishes (United States)

    Happell, Austin; Pattridge, Robert; Rinchard, Jacques; Walsh, Maureen


    Fatty acid profiles are used in food web studies to assess trophic interactions between predator and prey. The present study provides the first comprehensive fatty acid dataset for important prey and predator species in Lake Ontario. Three major prey fish (alewife, rainbow smelt, and round goby) were collected at three sites along the southern shore of Lake Ontario during the spring and fall of 2013, and predator species were collected in similar locations during the summer of 2013. Fatty acid compositions were compared among all prey species, all predator species, and information from both predator and prey was used to infer foraging differences among predators. Seasonal differences in fatty acids were found within each prey species studied. Differences among prey species were greater than any spatio-temporal differences detected within species. Fatty acids of predators revealed species-specific differences that matched known foraging habits. Chinook and Coho salmon, which are known to select alewife as their dominant prey item, had relatively little variation in fatty acid profiles. Conversely, brown trout, lake trout, yellow perch and esocids had highly variable fatty acid profiles and likely highly variable diet compositions. In general, our data suggested three dominant foraging patterns: 1) diet composed of nearly exclusively alewife for Chinook and Coho Salmon; 2) a mixed diet of alewife and round goby for brown and lake trout, and both rock and smallmouth bass; 3) a diet that is likely comprised of forage fishes other than those included in our study for northern pike and chain pickerel.

  6. A Bayesian assessment of the mercury and PCB temporal trends in lake trout (Salvelinus namaycush) and walleye (Sander vitreus) from lake Ontario, Ontario, Canada. (United States)

    Visha, Ariola; Gandhi, Nilima; Bhavsar, Satyendra P; Arhonditsis, George B


    Polychlorinated biphenyls (PCBs) and total mercury (THg) are two of the most prevalent contaminants, resulting in restrictive advisories on consuming fish from the Laurentian Great Lakes. The goal of this study is to examine the temporal trends of the two contaminants in walleye (Sander vitreus) and lake trout (Salvelinus namaycush) for Lake Ontario. We employed Bayesian inference techniques to parameterize three different strategies of time series analysis: dynamic linear, exponential decay, and mixed-order modeling. Our analysis sheds light on the role of different covariates (length, lipid content) that can potentially hamper the detection of the actual temporal patterns of fish contaminants. Both PCBs and mercury demonstrate decreasing temporal trends in lake trout males and females. Decreasing PCB trends are evident in walleye, but the mean annual mercury levels are characterized by a "wax and wane" pattern, suggesting that specific fish species may not act as bio-indicators for all contaminants. This finding may be attributed to the shifts in energy trophodynamics along with the food web alterations induced from the introduction of non-native species, the intricate nature of the prey-predator interactions, the periodicities of climate factors, and the year-to-year variability of the potentially significant fluxes from atmosphere or sediments. Finally, a meaningful risk assessment exercise will be to elucidate the role of within-lake fish contaminant variability and evaluate the potential bias introduced when drawing inference from pooled datasets. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Feeding ecology and niche overlap of Lake Ontario offshore forage fish assessed with stable isotopes (United States)

    Mumby, James; Johson, Timothy; Stewart, Thomas; Halfyard, Edward; Walsh, Maureen; Weidel, Brian C.; Lantry, Jana; Fisk, Aarron


    The forage fish communities of the Laurentian Great Lakes continue to experience changes that have altered ecosystem structure, yet little is known about how they partition resources. Seasonal, spatial and body size variation in δ13C and δ15N was used to assess isotopic niche overlap and resource and habitat partitioning among the five common offshore Lake Ontario forage fish species (n = 2037) [Alewife (Alosa pseudoharengus), Rainbow Smelt (Osmerus mordax), Round Goby (Neogobius melanostomus), and Deepwater (Myoxocephalus thompsonii) and Slimy (Cottus cognatus) Sculpin]. Round Goby had the largest isotopic niche (6.1‰2, standard ellipse area (SEAC)), followed by Alewife (3.4‰2) while Rainbow Smelt, Slimy Sculpin and Deepwater Sculpin had the smallest and similar niche size (1.7-1.8‰2), with only the Sculpin species showing significant isotopic niche overlap (>63%). Stable isotopes in Alewife, Round Goby and Rainbow Smelt varied with location, season and size, but did not in the Sculpin spp. Lake Ontario forage fish species have partitioned food and habitat resources, and non-native Alewife and Round Goby have the largest isotopic niche, suggestive of a boarder ecological niche, and may contribute to their current high abundance.

  8. Cooperative science to inform Lake Ontario management: Research from the 2013 Lake Ontario CSMI program (United States)

    Watkins, James M.; Weidel, Brian C.; Fisk, Aaron T.; Rudstam, Lars G.


    Since the mid-1970s, successful Lake Ontario management actions including nutrient load and pollution reductions, habitat restoration, and fish stocking have improved Lake Ontario. However, several new obstacles to maintenance and restoration have emerged. This special issue presents management-relevant research from multiple agency surveys in 2011 and 2012 and the 2013 Cooperative Science and Monitoring Initiative (CSMI), that span diverse lake habitats, species, and trophic levels. This research focused on themes of nutrient loading and fate; vertical dynamics of primary and secondary production; fish abundance and behavior; and food web structure. Together these papers identify the status of many of the key drivers of the Lake Ontario ecosystem and contribute to addressing lake-scale questions and management information needs in Lake Ontario and the other Great Lakes and connecting water bodies.

  9. Early fire history near Papineau lake, Ontario (United States)

    Daniel C. Dey; Richard P. Guyette


    Research that defines the role of fire in upland red oak-pine ecosystems in central Ontario is being conducted by the Great Lakes-St. Lawrence Silviculture program. Site-specific fire histories are being developed that document fire frequency, fire behavior, fire effects on forest regeneration and grwoth, and the influnce of human activites on fire disturbances. This...

  10. Deep structure beneath Lake Ontario: Crustal-scale Grenville subdivisions (United States)

    Forsyth, D. A.; Milkereit, B.; Zelt, Colin A.; White, D. J.; Easton, R. M.; Hutchinson, Deborah R.


    Lake Ontario marine seismic data reveal major Grenville crustal subdivisions beneath central and southern Lake Ontario separated by interpreted shear zones that extend to the lower crust. A shear zone bounded transition between the Elzevir and Frontenac terranes exposed north of Lake Ontario is linked to a seismically defined shear zone beneath central Lake Ontario by prominent aeromagnetic and gravity anomalies, easterly dipping wide-angle reflections, and fractures in Paleozoic strata. We suggest the central Lake Ontario zone represents crustal-scale deformation along an Elzevir–Frontenac boundary zone that extends from outcrop to the south shore of Lake Ontario.Seismic images from Lake Ontario and the exposed western Central Metasedimentary Belt are dominated by crustal-scale shear zones and reflection geometries featuring arcuate reflections truncated at their bases by apparent east-dipping linear reflections. The images show that zones analogous to the interpreted Grenville Front Tectonic Zone are also present within the Central Metasedimentary Belt and support models of northwest-directed crustal shortening for Grenvillian deep crustal deformation beneath most of southeastern Ontario.A Precambrian basement high, the Iroquoian high, is defined by a thinning of generally horizontal Paleozoic strata over a crestal area above the basement shear zone beneath central Lake Ontario. The Iroquoian high helps explain the peninsular extension into Lake Ontario forming Prince Edward County, the occurrence of Precambrian inlier outcrops in Prince Edward County, and Paleozoic fractures forming the Clarendon–Linden structure in New York.

  11. Application of a Spectral Wave Model to Assess Breakwater Configurations at a Small Craft Harbour on Lake Ontario

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    Amelia H. Cooper


    Full Text Available A surface wave model using three nested grids is applied to the eastern end of Lake Ontario to investigate wave propagation from an open lake environment to a small craft harbour protected by a breakwater. The Simulating WAves Nearshore (SWAN spectral wave model, coupled with the Delft3D hydrodynamic model, is applied to simulate a series of storms in November, 2013. The model results are compared to observations from two pressure sensors, and used to quantify wave properties around existing and future breakwaters to evaluate the bulk changes to the harbour configuration. Overall, the results indicate that the rubblemound breakwater reduces wave heights in the existing harbour by 63% compared to no breakwater, and that the addition of a surface breakwater extension could reduce wave heights by an additional 54%. Wave height attenuation was found to be highly dependent on the incident wave direction relative to breakwater orientation. The spectral wave model is useful for simulating wave transformation for broad directional spectra in wind-sea conditions over large scales to semi-protected areas such as small craft harbours.

  12. Groundwater Management Along Lake Ontario's North Shore (United States)

    Holysh, S.; Gerber, R.; Doughty, M.


    A large stretch of the north shore of Lake Ontario is characterized by a till plain that slopes down from the Oak Ridges Moraine, a 160 km long ridge of sand, silt and gravel deposits oriented in an approximately east-west direction north of Lake Ontario. Since 2000, an ongoing collaborative, multi-faceted program has been underway to better characterize the groundwater flow system on the Lake's north shore. The program is a collaborative effort between Conservation Authorities (Ontario's watershed management bodies), and several large municipalities (City of Toronto, Regional Municipalities of Peel, York and Durham). The program has three main components: database, geology and groundwater flow modeling; each of which is being actively managed and updated. In Ontario, as in many jurisdictions in North America, water and environmental data has long been neglected. Studies that involve the measurement of hydrological parameters and the collection of useful data are commonly required for approval of land use change by provincial, regional and/or local government agencies. So although data is frequently collected (at a considerable cost), it has never been rigorously assembled into a comprehensive database that can be used for future reference. Rather, the data is collected by consultants, reported through various studies, and then simply lost in archived files. In a similar fashion, individuals at many government agencies have collected water related data that now reside in locations unknown and, thus, unavailable to others in the organization. With this in mind, a comprehensive digital database was assembled to establish the foundation for long term successful groundwater management. The data model design incorporates information required for groundwater modeling purposes, thus extending beyond that of traditional groundwater information. The key data sources include borehole geology, water levels, pumping rates, surface water flows, climate data and water quality

  13. 2001 USACE LRE Topobathy Lidar: Lake Ontario (NY) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Office for Coastal Management received the 2001 Lake Ontario dataset with 2 separate metadata records in 2013 on a hard-drive device from the USGS Center for...

  14. Sea lamprey mark type, marking rate, and parasite-host relationships for lake trout and other species in Lake Ontario (United States)

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


    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.

  15. A population on the rise: The origin of deepwater sculpin in Lake Ontario (United States)

    Welsh, Amy B.; Scribner, Kim T.; Stott, Wendylee; Walsh, Maureen


    Deepwater sculpin, Myoxocephalus thompsonii, were thought to have been extirpated from Lake Ontario. However, in recent years, abundance has increased and recruitment has been documented. There are two hypotheses concerning the origin of the current Lake Ontario deepwater sculpin population. First, individuals from the upper Great Lakes may have recolonized Lake Ontario. Alternatively, the Lake Ontario population may have not been extirpated, and the remnant population has recovered naturally. To test these hypotheses, eight microsatellite loci were used to analyze samples from the current Lake Ontario population, museum specimens from the historic Lake Ontario population, and current upper Great Lakes populations. The genetic data suggest that historically throughout the Great Lakes, deepwater sculpin exhibited low levels of spatial genetic structure. Approximate Bayesian Computation analyses support the hypothesis that the current Lake Ontario population is more closely related to populations in the upper Great Lakes than to the historic Lake Ontario samples, indicating that the current Lake Ontario population likely resulted from recolonization from the Upper Great Lakes. The current Lake Ontario population has reduced allelic diversity relative to upper Great Lakes populations, indicating a possible founder effect. This study demonstrates the role life history variation can play in recolonization success. The pelagic larval phase of the deepwater sculpin allowed recolonization of Lake Ontario via passive larval drift.

  16. Concentration and biochemical gradients of seston in Lake Ontario (United States)

    Kelly, Patrick T.; Weidel, Brian C.; Paufve, Matthew R.; O'Malley, Brian P.; Watkins, James M.; Rudstam, Lars G.; Jones, Stuart E.


    Spatial variability in resource quantity and quality may have important implications for the distribution and productivity of primary consumers. In Lake Ontario, ecosystem characteristics suggest the potential for significant spatial heterogeneity in seston quantity and quality, particularly due to the potential for nearshore-offshore gradients in allochthonous nutrient supply, and the formation of a deep chlorophyll layer (DCL) in July. We assessed total and zooplankton food particle size-fractionated chlorophyll a concentrations, as well as carbon-to-phosphorus stoichiometry and essential fatty acid composition of seston across a distance-from-shore and depth transect. We observed time, sampling depth, and distance from shore to be the best predictors of chlorophyll a concentration. Resource quality was much more homogenous in space, but there were strong patterns through time, as both stoichiometric and fatty acid qualities in general were greatest in May, and lowest in July/August. We did observe a peak in essential fatty acid concentration near the DCL in during time of formation, possibly due to differences in phytoplankton community composition between the DCL and epilimnion. These results suggest the potential for a spatially and temporally dynamic resource base for consumers in Lake Ontario, which may be important in developing a broader understanding of variable consumer productivity.

  17. /sup 137/Cs radioactive dating of Lake Ontario sediment cores

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    Ward, T.E.; Breeden, J.; Komisarcik, K.; Porter, R.; Czuczwa, J.; Kaminski, R.; McVeety, B.D.


    The distribution of /sup 137/Cs in sediment cores from Lake Ontario provides estimates of the sediment accumulation rates. Geochronology with /sup 210/Pb dating and distribution of Ambrosia (ragweed) pollen compare well with /sup 137/Cs dating. These methods can determine with precision, changes in sedimentation occurring over the past 100 years or so. Typical sedimentation rates of 0.18-0.36 cm/yr were measured. 16 refs., 3 figs., 2 tabs.

  18. Deepwater sculpin status and recovery in Lake Ontario (United States)

    Weidel, Brian C.; Walsh, Maureen; Connerton, Michael J.; Lantry, Brian F.; Lantry, Jana R.; Holden, Jeremy P.; Yuille, Michael J.; Hoyle, James A.


    Deepwater sculpin are important in oligotrophic lakes as one of the few fishes that use deep profundal habitats and link invertebrates in those habitats to piscivores. In Lake Ontario the species was once abundant, however drastic declines in the mid-1900s led some to suggest the species had been extirpated and ultimately led Canadian and U.S. agencies to elevate the species' conservation status. Following two decades of surveys with no captures, deepwater sculpin were first caught in low numbers in 1996 and by the early 2000s there were indications of population recovery. We updated the status of Lake Ontario deepwater sculpin through 2016 to inform resource management and conservation. Our data set was comprised of 8431 bottom trawls sampled from 1996 to 2016, in U.S. and Canadian waters spanning depths from 5 to 225 m. Annual density estimates generally increased from 1996 through 2016, and an exponential model estimated the rate of population increase was ~ 59% per year. The mean total length and the proportion of fish greater than the estimated length at maturation (~ 116 mm) generally increased until a peak in 2013. In addition, the mean length of all deepwater sculpin captured in a trawl significantly increased with depth. Across all years examined, deepwater sculpin densities generally increased with depth, increasing sharply at depths > 150 m. Bottom trawl observations suggest the Lake Ontario deepwater sculpin population has recovered and current densities and biomass densities may now be similar to the other Great Lakes.

  19. Effect of lake-wide planktivory by the pelagic prey fish community in Lakes Michigan and Ontario (United States)

    Rand, Peter S.; Stewart, Donald J.; Lantry, Brian F.; Rudstam, Lars G.; Johannsson, Ora E.; Goyke, Andrew P.; Brandt, Stephen B.; O'Gorman, Robert; Eck, Gary W.


    We compared predatory demand by pelagic planktivorous prey fish with invertebrate production in Lake Michigan during 1987 and in Lake Ontario during 1990. Predation by the planktivores in Lake Ontario was nearly fourfold higher than in Lake Michigan (approx. 87 g wet weight∙m−2∙year−1). Predation rates on Mysis were comparable in Lakes Michigan and Ontario (approx. 21 g∙m−2∙year−1), while predation on Diporeia was markedly higher in Lake Michigan than in Lake Ontario (21.3 vs. 8.5 g wet weight∙m−2∙year−1). In Lake Ontario, predatory demand on zooplankton exceeded our best estimate of production by a factor of 1.7. Similarly, predation estimates on Mysis in Lake Ontario were 1.2–2.0 times the estimated rate of production, depending on the production model used. Lake Michigan planktivores consumed approximately 55% of available zooplankton production in 1987, indicating that competition for prey resources, if operating, was not as intense as that in Lake Ontario in 1990. It is unclear how to resolve the paradox that predation could markedly exceed available prey production in some cases. There could be sources of error in the estimates of both the supply and demand sides of these trophic relationships.

  20. Sea lamprey mark type, wounding rate, and parasite-host preference and abundance relationships for lake trout and other species in Lake Ontario (United States)

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


    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.

  1. Sexual difference in PCB concentrations of lake trout (Salvelinus namaycush) from Lake Ontario (United States)

    Madenjian, Charles P.; Keir, Michael J.; Whittle, D. Michael; Noguchi, George E.


    We determined polychlorinated biphenyl (PCB) concentrations in 61 female lake trout (Salvelinus namaycush) and 71 male lake trout from Lake Ontario (Ontario, Canada and New York, United States). To estimate the expected change in PCB concentration due to spawning, PCB concentrations in gonads and in somatic tissue of lake trout were also determined. In addition, bioenergetics modeling was applied to investigate whether gross growth efficiency (GGE) differed between the sexes. Results showed that, on average, males were 22% higher in PCB concentration than females in Lake Ontario. Results from the PCB determinations of the gonads and somatic tissues revealed that shedding of the gametes led to 3% and 14% increases in PCB concentration for males and females, respectively. Therefore, shedding of the gametes could not explain the higher PCB concentration in male lake trout. According to the bioenergetics modeling results, GGE of males was about 2% higher than adult female GGE, on average. Thus, bioenergetics modeling could not explain the higher PCB concentrations exhibited by the males. Nevertheless, a sexual difference in GGE remained a plausible explanation for the sexual difference in PCB concentrations of the lake trout.

  2. Blueback herring (Alosa aestivalis) in Lake Ontario: First record, entry route, and colonization potential (United States)

    Owens, Randall W.; O'Gorman, Robert; Mills, Edward L.; Rudstam, Lars G.; Hasse, John J.; Kulik, Brandon H.; MacNeill, David B.


    Two juvenile blueback herring (Alosa aestivalis) were caught in Lake Ontario in October 1995, the first record of this anadromous marine clupeid in the Great Lakes. Blueback herring most likely gained entry to Lake Ontario via the Erie Barge Canal, a navigation canal that links the Mohawk-Hudson rivers, which drain to the Atlantic Ocean, to Oneida Lake, which drains to Lake Ontario through the Oneida-Oswego rivers. Blueback herring ascend the Hudson River to spawn and were first reported from the upper Mohawk River in 1978. They currently spawn in several of the upper Mohawk's tributaries, including one about 430 km from the ocean but only 25 km from Oneida Lake. They were first found in Oneida Lake in 1982 and, in fall 1994, large numbers of juvenile blueback herring were found moving down the Oswego River. In the southern United States, blueback herring established self-reproducing populations in several reservoirs, and thus they have the potential to colonize Lake Ontario. If blueback herring became established in Lake Ontario, they could spread to other Great Lakes and impede recovery of depressed populations of indigenous fishes, like lake herring (Coregonus artedi) and lake trout (Salvelinus namaycush), through competition with, or predation on, their larvae.

  3. Simulation of rapid ecological change in Lake Ontario (United States)

    McKenna, James E.; Chalupnicki, Marc; Dittman, Dawn E.; Watkins, James M.


    Lower trophic level processes are integral to proper functioning of large aquatic ecosystems and have been disturbed in Lake Ontario by various stressors including exotic species. The invasion of benthic habitats by dreissenid mussels has led to systemic changes and native faunal declines. Size-dependent physiological rates, spatial differences and connectivity, competition, and differential population dynamics among invertebrate groups contributed to the change and system complexity. We developed a spatially explicit, individual-based mechanistic model of the benthic ecosystem in Lake Ontario, with coupling to the pelagic system, to examine ecosystem dynamics and effects of dreissenid mussel invasion and native fauna losses. Benthic organisms were represented by functional groups; filter-feeders (i.e., dreissenid mussels), surface deposit-feeders (e.g., native amphipod Diporeia spp.), and deposit-feeders (e.g., oligochaetes and other burrowers). The model was stable, represented ecological structure and function effectively, and reproduced observed effects of the mussel invasion. Two hypotheses for causes of Diporeia loss, competition or disease-like mortality, were tested. Simple competition for food did not explain observed declines in native surface deposit-feeders during the filter-feeder invasion. However, the elevated mortality scenario supports a disease-like cause for loss of the native amphipod, with population changes in various lake areas and altered benthic biomass transfers. Stabilization of mussel populations and possible recovery of the native, surface-deposit feeding amphipod were predicted. Although further research is required on forcing functions, model parameters, and natural conditions, the model provides a valuable tool to help managers understand the benthic system and plan for response to future disruptions.

  4. A synthesis of ecological and fish-community changes in Lake Ontario, 1970-2000 (United States)

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


    We assessed stressors associated with ecological and fishcommunity changes in Lake Ontario since 1970, when the first symposium on Salmonid Communities in Oligotrophic Lakes (SCOL I) was held (J. Fish. Res. Board Can. 29: 613-616). Phosphorus controls implemented in the early 1970s were undeniably successful; lower food-web studies showed declines in algal abundance and epilimnetic zooplankton production and a shift in pelagic primary productivity toward smaller organisms. Stressors on the fish community prior to 1970 such as exploitation, sea lamprey (Petromyzon marinus) predation, and effects of nuisance populations of alewife (Alosa pseudoharengus) were largely ameliorated by the 1990s. The alewife became a pivotal species supporting a multi-million-dollar salmonid sport fishery, but alewife-induced thiamine deficiency continued to hamper restoration and sustainability of native lake trout (Salvelinus namaycush). Expanding salmonine populations dependent on alewife raised concerns about predator demand and prey supply, leading to reductions in salmonine stocking in the early 1990s. Relaxation of the predation impact by alewives and their shift to deeper water allowed recovery of native fishes such as threespine stickleback (Gasterosteus aculeatus) and emerald shiner (Notropis atherinoides). The return of the Lake Ontario ecosystem to historical conditions has been impeded by unplanned introductions. Establishment of Dreissena spp. led to increased water clarity and increased vectoring of lower trophic-level production to benthic habitats and contributed to the collapse of Diporeia spp. populations, behavioral modifications of key fish species, and the decline of native lake whitefish (Coregonus clupeaformis). Despite reduced productivity, exotic-species introductions, and changes in the fish community, offshore Mysis relicta populations remained relatively stable. The effects of climate and climate change on the population abundance and dynamics of Lake Ontario

  5. Acidic lakes in Ontario: characterization, extent, and responses to base and nutrient additions

    National Research Council Canada - National Science Library

    Dillon, P.J; Yan, N.D; Scheider, W.A; Conroy, N


    The Sudbury Environmental Study was initiated in 1973 in part to determine the geographical extent of acidic lakes in the area of Sudbury, Ontario, to characterize the chemical and biological nature...

  6. Exploring elements that influence stewardship in the eastern Lake Ontario dune and wetland area (United States)

    Diane Kuehn; James. Smahol


    Th e Eastern Lake Ontario Dune and Wetland Area (ELODWA) is a 17-mile stretch of sand dunes, wetlands, and woodlands along the eastern shore of Lake Ontario in New York State. Reductions in negative, visitor-caused impacts on the dunes (e.g., trampling of dune vegetation and sand erosion) are thought to be due in part to the extensive visitor education efforts of...

  7. Paternal Lake Ontario fish consumption and risk of conception delay, New York state angler cohort

    Energy Technology Data Exchange (ETDEWEB)

    Buck, G.M.; Mendola, P.; Vena, J.E.; Kostyniak, P.; Greizerstein, H.; Olson, J.; Stephen, F.D. [State Univ. of New York, Buffalo, NY (United States). Dept. of Social and Preventive Medicine; Sever, L.E. [Battelle, Seattle, WA (United States). Centers for Public Health and Evaluation


    The aquatic ecosystems of the Great Lakes are contaminated with a variety of compounds, some of which are considered reproductive toxicants. Few studies of paternal fish consumption and reproductive endpoints have been undertaken and serve as the impetus for study. Standardized telephone interviews were conducted with 2,445 female members of the New York State Angler Cohort (82% response) to update reproductive profiles and to ascertain specific information on time-to-pregnancy (TTP). The study sample includes women with a known TTP and paternal fish consumption data (n = 785). Conception delay was defined as more than 12 cycles of unprotected intercourse to achieve pregnancy. Paternal fish consumption was assessed by three measures: frequency of Lake Ontario sport fish meals in 1991, numbers of years eating fish, and estimated PCB exposure from fish consumption. Adjusted ORs for number of fish meals, based on logistic regression, ranged from 0.69 to 0.80; from 0.61 to .82 for number of years eating fish; and from 0.44 to 1.14 for quartiles of estimated PCB exposure from fish consumption. All confidence intervals included one. These findings suggest that, based on paternal self-reports, Lake Ontario fish consumption does not increase the risk of conception delay.

  8. Analysis of three cisco forms (Coregonus, Salmonidae) from Lake Saganaga and adjacent lakes near the Minnesota/Ontario border

    NARCIS (Netherlands)

    Etnier, DA; Skelton, CE


    Based on examination of 655 ciscoes from Lake Saganaga, a Minnesota/Ontario border lake, three forms, about 90% separable on gill raker counts, are present. Form L, with the lowest gill raker counts (26-40, mean = 31.9, n = 96) is tentatively identified as Coregonus zenithicus. Form M, with

  9. Maternal characteristics versus egg size and energy density: do stocked lake trout in Lake Ontario experience premature reproductive senescence? (United States)

    Lantry, B.F.; O'Gorman, R.; Machut, L.S.


    Observations from September 1994 and 1997 collections of hatchery-origin, mature female lake trout (Salvelinus namaycush) from Lake Ontario indicated that egg mass decreased with age, fueling the notion that stocked fish experienced premature reproductive senescence. Supplemental collections during September 2002 and November 2002-2004 were combined with the 1994 and 1997 samples to examine whether sample date or maternal age, body mass, condition (K), egg count, or strain were related to egg mass or energy content (percentage dry mass [%DM]). Body mass was correlated with egg mass for age ≥ 8 lake trout sampled in September, and egg count was correlated with egg mass for September age-6 lake trout only. Within each month, egg mass was not related to K or egg %DM, however, egg %DM was 1.52% greater (P ≤ 0.0247) in November than in September which is equivalent to a 110 cal/g difference. Samples were grouped for the three most abundant strains (Seneca, Superior, and Ontario) after finding no strain or year effects from our 1994 and 1997 samples and based on life history data from the literature and our assessment sampling. Further analysis indicated that September egg masses were greater for fish ages ≤ 6 than for fish ages ≥ 8. The age effect disappeared in November when mean egg mass across all ages (0.078 g) was greater than September means (P < 0.0005) for ages -5 (0.054 g), -6 (0.057 g) and ≥ 8 (0.041 g). Our results indicate that the decrease in egg mass with female age in September was not due to senescence, but to oogenesis being closer to completion in young age-5 and -6 fish than in older individuals.

  10. National Lakes Assessment Data (United States)

    U.S. Environmental Protection Agency — The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S....

  11. Recovery and decline of lake whitefish in U.S. waters of eastern Lake Ontario, 1980-2001 (United States)

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


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

  12. Loss of glutathione S-transferases in pollution-associated liver neoplasms in white suckers (Catostomus commersoni) from Lake Ontario

    National Research Council Canada - National Science Library

    Stalker, M J; Kirby, G M; Kocal, T E; Smith, I R; Hayes, M A


    White suckers (Catostomus commersoni) are one of two species of bottom-feeding fish in which various liver neoplasms are more prevalent in urban/industrial sites in western Lake Ontario than in less polluted sites in the Great Lakes...

  13. Status of important prey fishes in the U.S. waters of Lake Ontario, 2013: Introduction and methods, alewife, rainbow smelt, sculpins, and round goby (United States)

    Walsh, Maureen; Weidel, Brian C.; Connerton, Michael J.


    Lake Ontario has a mean depth of 86 m (282 ft) and a maximum depth of 244 m (801 ft) (Herdendorf 1982). The southern, New York portion of the lake has the deepest water (Figure 1). In New York waters, about 67% of the lake is lake is Lake Ontario prey fishes each year since 1978. Bottom trawl assessments were initially focused on Alewife Alosa pseudoharengus (April), Rainbow Smelt Osmerus mordax (June), and Slimy Sculpin Cottus cognatus (October). Seasonal survey timing corresponded to the peak catches in 1972 when collections were made every month May to October (Owens et al. 2003). Twelve transects were established at approximately 25-km intervals along the U.S. shoreline (Figure 2). Alewife assessment was conducted at all transects, Rainbow Smelt assessment at all transects except Fair Haven, and six transects representing eastern, southern, and western lake areas were sampled for Slimy Sculpin (Figure 2). Changes in the Lake Ontario ecosystem (species invasion, oligotrophication, native species rebound) require ongoing evaluation of current methods which sometimes necessitate redistribution of trawl effort, or changes in sampling designs and/or gear. For instance, the spring Alewife assessment is now used also to assess invasive Round Goby Neogobius melanostomus population dynamics. Likewise, the fall benthic fish assessment (formerly sculpin assessment) now also tracks dynamics of the rebounding native Deepwater Sculpin Myoxocephalus thompsonii population, the apparent declining population of Slimy Sculpin, and fall distribution of Round Goby.

  14. Mo & Fe Influences on Nitrate Assimilation in Lake Ontario and the St Lawrence River (United States)

    Twiss, M. R.; Salk, K.; Avolio, L. N.; Chappaz, A.; Ostrom, N. E.


    Lake Ontario has undergone a steady increase in nitrate since the early 1970s, a phenomenon also occurring in other large lakes. Possible causes of this increase include rising urban and agricultural runoff, atmospheric deposition, less demand for N due to effective point source P control, and trace metal-N co-limitation as observed in Lake Erie. Despite the abundance of nitrate in Lake Ontario, heterocystous cyanobacteria have been detected here setting up the paradoxical situation wherein some cyanobacteria are investing in the more costly diazotrophy whilst surrounded by a form of N that requires less energy and metal quota to assimilate. Mo and Fe are involved in reductive nitrate assimilation making it possible that reductive nitrate assimilation in Lake Ontario is limited in phytoplankton by low trace metal bioavailability. To test this hypothesis, 1-d enrcihment experiments were conducted using trace metal clean techniques in June 2013 at two coastal sites in Lake Ontario, and 4-d enrichment experiments were conducted in July 2013 on main channel waters of the St. Lawrence River, the outflow of Lake Ontario. Water was sampled from the metalimnion of Lake Ontario and from surface water of the main channel of the river. Water was enriched with the the following treatments in triplicate: control, 100 nM KH2PO4, 50 nM FeCl3, 50 nM Na2MoO4, and a mix of P, Fe & Mo. Experiments in the river showed significant effects due to P (increase in Chl-a, NO3 and SiO2 drawdown, changes in phytoplankton community, increase in photosynthetic efficiency [Fv/Fm]) but less impact of trace metals relative to control, presumably due to greater ambient trace metal bioavailability. As measured using FluoroProbe, the phytoplankton community changed very little (over 1 d) in lake waters; there was no significant change in total chl-a. However, as in the river, Fv/Fm revealed significant metal and P effects with the P, Fe & Mo mix being significantly greater than control (Fig. 1; we

  15. Utilization of bathymetry data to examine lead sediment contamination distributions in Lake Ontario

    Directory of Open Access Journals (Sweden)

    Chris H. Marvin


    Full Text Available Bathymetry data offer interesting opportunities for the analysis of contaminant distribution patterns. This research utilized lead surficial sediment sample data from Lake Ontario that were collected by the Canada Centre for Inland Waters in 1968 and 1998. Traditionally, two-dimensional analyses such as dot maps or proportional circle representation have been utilized to examine pollutant levels. Generating area estimates allows for expanded spatial analysis of contaminant distribution patterns. Lake-wide surfaces were derived using the ordinary kriging technique. These were then layered on bathymetry data to examine three-dimensional relationships between observed pollution patterns and lake-bottom features. Spatial variability was observed in both the 1968 and 1998 datasets. Contamination levels in 1998 dropped substantially, especially in areas that were previously the most heavily polluted and above the Probable Effect Level (4660.23 km2 or 26.72% of the common analysis area lake-bottom in 1998 versus 6189.07 km2 or 62.00% in 1968. Conversely, areas below the Threshold Effect Level increased from 922.09 km2 (5.29% in 1968 to 3484.22 km2 (19.98% in 1998. In both years, shallow and sill/ridge areas tended to have lower levels of contamination than deeper lake basins or contaminant inflow areas. The 1968 dataset likely provides a more detailed estimation surface as there were more points available for interpolation procedures. The kriging surfaces when combined with bathymetry, sedimentology information, and knowledge of physical processes provide a comprehensive illustration of the contaminant distributions whether they are high (1968 or when loadings are significantly reduced (1998. The results have implications for future sediment assessment programs and survey design on a lake-wide basis. The bathymetry data allowed for enhanced interpretation and an improved understanding of observed lead pollution patterns.

  16. A heuristic simulation model of Lake Ontario circulation and mass balance transport (United States)

    McKenna, J.E.; Chalupnicki, M.A.


    The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

  17. Confirmation of cisco spawning in Chaumont Bay, Lake Ontario using an egg pumping device (United States)

    George, Ellen M.; Stott, Wendylee; Young, Brian; Karboski, Curtis T.; Crabtree, Darran L.; Roseman, Edward; Rudstam, Lars G.


    Cisco Coregonus artedi, a historically abundant and commercially important fish in the Great Lakes, have declined drastically in the last century due to the impacts of invasive species, overfishing, and habitat degradation. Chaumont Bay, New York is believed to contain one of the last remaining spawning populations of cisco in Lake Ontario although direct evidence of spawning has remained elusive. We document cisco spawning in Chaumont Bay for the first time in decades through the use of an egg pumping device specifically developed to sample through lake ice. Forty-one eggs were identified as cisco using genetic barcoding of the mitochondrial cytochrome c oxidase I (COI) gene. Cisco eggs were associated with shallow, rocky shoals. Contemporary knowledge of spawning behavior is an important step toward the successful restoration of cisco in Lake Ontario and across the Great Lakes.

  18. Evaluation of ERTS data for certain oceanographic uses. [precipitation of calcium carbonate in Lake Michigan, Lake Erie, and Lake Ontario (United States)

    Strong, A. E. (Principal Investigator)


    The author has identified the following significant results. According to Lake Michigan records, the pH levels have been steadily increasing as the lake becomes more eutrophic. Numerous upwellings during the summer of 1973, beginning with the late July event, appear to be triggering a chemical precipitation of calcium carbonate. The upwelling provides abundant carbon dioxide into the surface water and results in massive blooms of phytoplankton. As the CO2 is utilized by these microscopic plants the pH is increased (acidity decreases) and CaCO3 no longer is able to remain in solution. The precipitation takes place where the phytoplankton are living, near depths of 10 meters. Therefore, the whiting observed by ERTS-1 is only seen in the green band, as red cannot penetrate but a few meters. With these whitings, secci disc readings lower in July from 10-15 meters to 3-5 meters and green, milky water is observed by research vessels. It appears that whitings have been becoming more frequent since the middle 60's but until ERTS-1 the extent had never been realized. Calcium levels are too low, presently, for a similar precipitate in Lakes Huron or Superior. However, whitings have been seen by ERTS-1 in Lakes Erie and Ontario where the calcium ion and pH levels are more like those found in Lake Michigan.

  19. A presettlement fire history in an oak-pine forest near Basin Lake, Algonquin Park, Ontario (United States)

    Richard P. Guyette; Daniel C. Dey


    Fire scars from natural remnants of red pine (Pinus resinosa Ait.) in an oak-pine forest near Basin Lake, Algonquin Park, Ontario, were dated using dendrochronological methods. A fire scar chronology was constructed from 28 dated fire scars on 26 pine remnants found in a 1 km2 area of this forest. From pith and outside ring...

  20. Constraints and motivations related to fishing along the Lake Ontario coast (United States)

    Matthew P. Brincka; Diane M. Kuehn; Valerie. Luzadis


    The number of nonresident anglers along the Lake Ontario coast has decreased over the past 15 years. Therefore, in order to sustain a strong sport fishing industry, local businesses and tourism promoters might want to tap into the large resident angler market group. This study examines resident anglers' social, environmental, and economic constraints/facilitators...

  1. Sources and sinks of microplastics in Canadian Lake Ontario nearshore, tributary and beach sediments. (United States)

    Ballent, Anika; Corcoran, Patricia L; Madden, Odile; Helm, Paul A; Longstaffe, Fred J


    Microplastics contamination of Lake Ontario sediments is investigated with the aim of identifying distribution patterns and hotspots in nearshore, tributary and beach depositional environments. Microplastics are concentrated in nearshore sediments in the vicinity of urban and industrial regions. In Humber Bay and Toronto Harbour microplastic concentrations were consistently >500 particles per kg dry sediment. Maximum concentrations of ~28,000 particles per kg dry sediment were determined in Etobicoke Creek. The microplastic particles were primarily fibres and fragments microplastics in terms of how and where to implement preventative measures to reduce the contaminant influx. Although the impacts of microplastics contamination on ecosystem health and functioning is uncertain, understanding, monitoring and preventing further microplastics contamination in Lake Ontario and the other Great Lakes is crucial. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Assessing Ontario's Personal Support Worker Registry

    Directory of Open Access Journals (Sweden)

    Audrey Laporte


    Full Text Available In response to the growing role of personal support workers (PSWs in the delivery of health care services to Ontarians, the Ontario government has moved forward with the creation of a PSW registry. This registry will be mandatory for all PSWs employed by publicly funded health care employers, and has the stated objectives of better highlighting the work that PSWs do in Ontario, providing a platform for PSWs and employers to more easily access the labour market, and to provide government with information for human resources planning. In this paper we consider the factors that brought the creation of a PSW registry onto the Ontario government’s policy agenda, discuss how the registry is being implemented, and provide an analysis of the strengths and weaknesses of this policy change.

  3. Diet, feeding patterns, and prey selection of subyearling Atlantic salmon (Salmo salar) and subyearling chinook salmon (Oncorhynchus tshawytscha) in a tributary of Lake Ontario (United States)

    Johnson, J. H.; Nash, K. J.; Chiavelli, R. A.; DiRado, J. A.; Mackey, G. E.; Knight, J. R.; Diaz, A. R.


    Since juvenile Atlantic salmon (Salmo salar) and Chinook salmon (Oncorhynchus tshawytscha) occupy a similar habitat in Lake Ontario tributaries, we sought to determine the degree of diet similarity between these species in order to assess the potential for interspecific competition. Atlantic salmon, an historically important but currently extirpated component of the Lake Ontario fish community, are the focus of a bi-national restoration effort. Presently this effort includes the release of hatchery produced juvenile Atlantic salmon in Lake Ontario tributaries. These same tributaries support substantial numbers of naturally reproduced juvenile Pacific salmonids including Chinook salmon. Subyearling Atlantic salmon and subyearling Chinook salmon had significantly different diets during each of the three time periods examined. Atlantic salmon fed slightly more from the benthos than from the drift and consumed mainly chirononmids (47.0%) and ephemeropterans (21.1%). The diet of subyearling Chinook salmon was more closely associated with the drift and consisted mainly of chironomids (60.2%) and terrestrial invertebrates (16.0%). Low diet similarity between subyearling Atlantic salmon and subyearling Chinook salmon likely minimizes competitive interactions for food between these species in Lake Ontario tributaries. However, the availability of small prey such as chironomids which comprise over 50% of the diet of each species, soon after emergence, could constitute a short term resource limitation. To our knowledge this is the first study of interspecific diet associations between these two important salmonid species.

  4. Physical, chemical, and biological characteristics of the Turkey Lakes Watershed, central Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Jeffries, D.S. (National Water Research Inst., Burlington, ON (Canada)); Kelso, J.R.M. (Great Lakes Fisheries Research Branch, Sault Ste. Marie, ON (Canada)); Morrison, I.K. (Great Lakes Forestry Centre, Sault Ste. Marie, ON (Canada))


    The Turkey Lakes Watershed (TLW) in Ontario is a natural region selected for intensive research into the effects of the long-range transport of air pollutants (primarily acidic deposition) at a site on the Canadian Shield having both vulnerable terrain and an undisturbed Great Lakes forest type. The terrestrial and aquatic resources within the basin are representative of the surrounding region of Algoma. The TLW contains a chain of four lakes that range from 5.8 to 52.0 hectares in area and 2.2 to 12.2m in mean depth. The lakes are dimictic and, except for the deepest lake, experience dissolved oxygen depletion in undisturbed bottom waters. There is a gradient in the major ion composition of the lakes within the TLW, the most dilute waters occurring at high elevations. Levels of Ca increase from 55 to 138 {mu}mole/l down the chain. Sulphate is the dominant lake water anion in the headwater lake, while alkalinity dominates in the lowest lake. Phosphorus is the limiting nutrient; NO{sub 3}-N levels are high (7.9-16.4 {mu}mole/l) because the terrestrial basin exhibits low utilization of this nitrogen species. Seasonal variations in the surface water composition can be large. The headwater lake contains no fish; however, fish communities in the lower three lakes are typical of the Algoma region. The distribution of benthic organisms is a function of lake depth and presence/absence of fish rather than variations in water chemistry. Zooplankton species composition is similar across all lakes, and cyanophytes are the dominant algae throughout. The principal tree species is sugar maple (90%). 46 refs., 3 figs., 8 tabs.

  5. Occurrence of Waterborne Pathogens and Escherichia coli at Offshore Drinking Water Intakes in Lake Ontario


    Edge, T. A.; Khan, I. U. H.; Bouchard, R.; Guo, J.; Hill, S.; Locas, A.; Moore, L.; Neumann, N.; Nowak, E.; Payment, P.; Yang, R.; Yerubandi, R.; Watson, S.


    The occurrence of waterborne pathogens was investigated at three drinking water intakes located about 2 km offshore in Lake Ontario. Water sampling was conducted over 3 years for Campylobacter spp., Cryptosporidium spp., Giardia spp., cultivable enteric viruses, and water quality parameters. All pathogens were detected in the offshore source water for each water treatment plant (WTP1 to WTP3), although at relatively low frequencies and concentrations. Giardia was the most common pathogen, occ...

  6. Fifty years environmental record at Elliot Lake, Ontario Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wiber, M.; Coggan, A. [Rio Algom Limited, Elliot Lake, Ontario (Canada)]. E-mail:;; Mansell, R. [Robert Mansell, Toronto, Ontario (Canada); Knapp, R. [SENES Consultants Ltd., Richmond Hill, Ontario (Canada)]. E-mail:


    Rio Algom Limited carries out care and maintenance of their uranium properties in the Elliot Lake area that were decommissioned and reclaimed during the 1990s. This included 10 underground mines, 8 metallurgical plants and 7 tailings areas. These historic mines were first developed in the mid-1950s to supply uranium to the United States and Britain for defence through Eldorado Mining and Refining. Seven were shut down by the early 1960s when the United States did not renew the contracts and did not reopen. Quirke, Panel and Stanleigh re-opened in the early 1980s to supply uranium for nuclear power plants. Stanleigh, the last operating mine, closed in 1996. Decommissioning and reclamation proposals were prepared for all sites and environmental assessments were completed for all of the properties in the late 1980s and 1990s. The decommissioning plans included the demolition of all surface facilities, sealing of the mine openings, and reclamation of the sites. The mine and mill sites were cleaned up, contoured and vegetated. Reclamation options were reviewed for each tailings area with the final closure plans including the flooding of 4 tailings areas, the covering and vegetation of 2 tailings areas and direct vegetation of 1 tailings area. In all cases, dams were either built or upgraded to meet Canadian Dam Safety Guidelines. Acid mine drainage has been curtailed at all of the flooded tailings areas with effluent treatment limited to polishing for radium 226 removal. The covered and vegetated sites are physically stable but continue to produce acidity which is treated at 2 lime treatment plants. The environmental assessments projected that for the selected reclamation plans, the area's ecology can be effectively protected, and that there are no impediments to the restoration of the entire Serpent River Watershed. Environmental monitoring has shown that the reclaimed sites are performing as expected, and that healthy aquatic communities are present in all major

  7. Lake Ontario: Food web dynamics in a changing ecosystem (1970-2000) (United States)

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


    We examined stressors that have led to profound ecological changes in the Lake Ontario ecosystem and its fish community since 1970. The most notable changes have been reductions in phosphorus loading, invasion by Dreissena spp., fisheries management through stocking of exotic salmonids and control of sea lamprey (Petromyzon marinus), and fish harvest by anglers and double-crested cormorants (Phalacrocorax auritus). The response to these stressors has led to (i) declines in both algal photosynthesis and epilimnetic zooplankton production, (ii) decreases in alewife (Alosa pseudoharengus) abundance, (iii) declines in native Diporeia and lake whitefish (Coregonus clupeaformis), (iv) behavioral shifts in alewife spatial distribution benefitting native lake trout (Salvelinus namaycush), threespine stickleback (Gasterosteus aculeatus), and emerald shiner (Notropis atherinoides) populations, (v) dramatic increases in water clarity, (vi) predation impacts by cormorants on select fish species, and (vii) lake trout recruitment bottlenecks associated with alewife-induced thiamine deficiency. We expect stressor responses associated with anthropogenic forces like exotic species invasions and global climate warming to continue to impact the Lake Ontario ecosystem in the future and recommend continuous long-term ecological studies to enhance scientific understanding and management of this important resource.

  8. Occurrence of waterborne pathogens and Escherichia coli at offshore drinking water intakes in lake Ontario. (United States)

    Edge, T A; Khan, I U H; Bouchard, R; Guo, J; Hill, S; Locas, A; Moore, L; Neumann, N; Nowak, E; Payment, P; Yang, R; Yerubandi, R; Watson, S


    The occurrence of waterborne pathogens was investigated at three drinking water intakes located about 2 km offshore in Lake Ontario. Water sampling was conducted over 3 years for Campylobacter spp., Cryptosporidium spp., Giardia spp., cultivable enteric viruses, and water quality parameters. All pathogens were detected in the offshore source water for each water treatment plant (WTP1 to WTP3), although at relatively low frequencies and concentrations. Giardia was the most common pathogen, occurring in 36% of water samples from the influent of WTP1 (n = 46), and with a maximum concentration of 0.70 cysts/liter in this influent. Cryptosporidium occurred as frequently as 15% in the WTP2 influent (n = 35), with a maximum concentration of 0.40 oocysts/liter in the WTP1 influent. The human Bacteroidales HF183 DNA marker was most common in the WTP1 influent (19%), and this was the only WTP where the Cryptosporidium hominis genotype was detected. No water quality parameter was predictive of pathogen occurrence across all three WTP influents. Escherichia coli was often below detection when pathogens were detected, and spikes in E. coli concentrations often did not coincide with pathogen occurrence. After summer rain events, river plumes had E. coli concentrations as high as 222 CFU/100 ml in surface waters 2 km offshore, without impacting drinking water intakes below the thermocline on the lake bottom. At times, prechlorination to control mussels at offshore intake cribs compromised the use of E. coli for "raw" water quality assessment, particularly for chlorine-resistant Cryptosporidium. E. coli measured by standard methods did not reliably predict pathogen occurrence at drinking water intakes in offshore ecosystems.

  9. Status of alewife and rainbow smelt in U.S. waters of Lake Ontario, 2015 (United States)

    Walsh, Maureen; Weidel, Brian C.; Connerton, Michael J.; Holden, Jeremy P.


    In 2015 the joint USGS and NYSDEC surveys for Alewife and Rainbow Smelt were combined for the first time into a comprehensive spring pelagic prey fish survey. The adult Alewife abundance and weight indices in 2015 increased slightly from 2014 levels, and adult Alewife abundance has remained relatively stable for the past five years. Adult Alewife condition in both spring and fall increased from 2014 values and was above long-term means. Yearling Alewife abundance was the lowest observed in the 38-year time series. Alewife year class strength at age 1 is related to the number of spawning adults and summer temperatures and winter duration in the first year after hatching. Moderate year classes were produced during 2009-2011, and 2012 was the largest year class in the time series. However, severe winters in 2013-2014 and 2014-2015 contributed to two successive very small year classes for the first time in the time series. We expect adult Alewife abundance and biomass to decline in 2016 as older and larger fish decline in the population. The number of spawning adults increased in 2015, summer temperatures were slightly below average, and the anticipated winter duration is below average (i.e., milder winter) for 2015-2016, so these conditions will likely produce a low to moderate year class. A third successive weak year class could be problematic for the Lake Ontario Alewife population and may be of concern to binational lake managers. Rainbow Smelt were also assessed and the population continues to persist at a low and stable level.

  10. Effects of food web changes on Mysis diluviana diet in Lake Ontario (United States)

    O'Malley, Brian P.; Rudstam, Lars G.; Watkins, James M.; Holda, Toby J.; Weidel, Brian C.


    Mysids are important benthic-pelagic omnivores in many deep-lake food webs, yet quantitative data on their diet are limited. We explored the trophic role of Mysis diluviana in offshore Lake Ontario using samples collected in May, July, and September 2013 with a focus on seasonal and ontogenetic patterns in herbivory and zooplanktivory using two approaches. We hypothesized that Mysis diet in 2013 differs from the last investigation in 1995 in response to changes in pelagic prey over 1995 to 2013. Gut fluorescence indicated high grazing by adult and juvenile Mysis in May 2013. In July, smaller mysids were more herbivorous than larger individuals, a pattern that was less pronounced in September. Microscopic gut analysis showed copepods, including Limnocalanus, were common in diets of both size groups in May. In July, mainly cladocerans were consumed, including Cercopagis pengoi which represents a change from a past investigation that preceded Cercopagis invasion in the lake. Our results are consistent with earlier observations of a larger proportion of algae in mysid diets in spring, transitioning to relatively more zooplanktivory and use of cladocerans in the summer and fall. Higher chlorophyll content in small mysids in July than in September may be associated with the presence of a deep chlorophyll layer in July that had largely dissipated by September. Overall, Mysis in Lake Ontario continues to be a generalist omnivore, incorporating new prey items and exhibiting higher herbivory in spring.

  11. Hidden plastics of Lake Ontario, Canada and their potential preservation in the sediment record. (United States)

    Corcoran, Patricia L; Norris, Todd; Ceccanese, Trevor; Walzak, Mary Jane; Helm, Paul A; Marvin, Chris H


    Microplastics are a source of environmental pollution resulting from degradation of plastic products and spillage of resin pellets. We report the amounts of microplastics from various sites of Lake Ontario and evaluate their potential for preservation in the sediment record. A total of 4635 pellets were sampled from the Humber Bay shoreline on three sampling dates. Pellet colours were similar to those from the Humber River bank, suggesting that the river is a pathway for plastics transport into Lake Ontario. Once in the lake, high density microplastics, including mineral-polyethylene and mineral-polypropylene mixtures, sink to the bottom. The minerals may be fillers that were combined with plastics during production, or may have adsorbed to the surfaces of the polymers in the water column or on the lake bottom. Based on sediment depths and accumulation rates, microplastics have accumulated in the offshore region for less than 38 years. Their burial increases the chance of microplastics preservation. Shoreline pellets may not be preserved because they are mingled with organic debris that is reworked during storm events. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Dissolved organic matter influences Fe-binding ligand availability for cyanobacteria in oligotrophic Ontario lakes (United States)

    Sorichetti, Ryan; Creed, Irena; Trick, Charles


    Natural iron (Fe) binding ligands, such as dissolved organic matter (DOM) and microbial-produced siderophores, are ubiquitously found in terrestrial and aquatic environments. Siderophores are a group of Fe-binding ligands primarily secreted by bacteria and fungi during Fe-limited conditions as a Fe-scavenging strategy. DOM can have high Fe-binding capacity if it is relatively refractory (i.e., high humic acid concentration with high affinity for metal ions). Cyanobacteria have been shown to utilize Fe bound to hydroxamate and catecholate siderophores when cells are Fe-limited. We assessed if the concentrations of DOM or the presence of siderophores, that increase when concentrations of ferric are low, in the water were correlated with the proportion of cyanobacteria in 25 oligotrophic lakes in Canada. We hypothesized that the highest siderophore concentration will be in lakes with modeled free ferric concentrations Siderophore concentrations were measured using two traditional chemical analyses (Czaky and Arnow tests). Cyanobacteria appeared to be regulated by the availability of ferric concentrations but the relationship was non-linear. The oligotrophic lakes had ferric concentrations that ranged from 1x10-25 M to 1x10-14 M. The highest % cyanobacteria occurred between ferric concentrations 1x10-23 M to 1x10-19 M. Hydroxamate siderophore concentrations showed the same pattern as % cyanobacteria across the modeled ferric gradient. In contrast, catecholate siderophore concentrations showed no relationship with % cyanobacteria or the modeled ferric gradient. A positive relationship was found between DOM quantity and catecholate siderophore concentration (R² = 0.65, psiderophore concentration decreased (R² = 0.74, psiderophore concentration increased (R² = 0.72, psiderophore concentration. Cyanobacteria appear to produce catecholate siderophores (with relatively stronger Fe-binding capacity) when refractory DOM is high in concentration making Fe-scavenging from DOM

  13. The effectiveness and resilience of phosphorus management practices in the Lake Simcoe watershed, Ontario, Canada (United States)

    Crossman, J.; Futter, M. N.; Palmer, M.; Whitehead, P. G.; Baulch, H. M.; Woods, D.; Jin, L.; Oni, S. K.; Dillon, P. J.


    Uncertainty surrounding future climate makes it difficult to have confidence that current nutrient management strategies will remain effective. This study used monitoring and modeling to assess current effectiveness (% phosphorus reduction) and resilience (defined as continued effectiveness under a changing climate) of best management practices (BMPs) within five catchments of the Lake Simcoe watershed, Ontario. The Integrated Catchment Phosphorus model (INCA-P) was used, and monitoring data were used to calibrate and validate a series of management scenarios. To assess current BMP effectiveness, models were run over a baseline period 1985-2014 with and without management scenarios. Climate simulations were run (2070-2099), and BMP resilience was calculated as the percent change in effectiveness between the baseline and future period. Results demonstrated that livestock removal from water courses was the most effective BMP, while manure storage adjustments were the least. Effectiveness varied between catchments, influenced by the dominant hydrological and nutrient transport pathways. Resilience of individual BMPs was associated with catchment sensitivity to climate change. BMPs were most resilient in catchments with high soil water storage capacity and small projected changes in frozen-water availability and in soil moisture deficits. Conversely, BMPs were less resilient in catchments with larger changes in spring melt magnitude and in overland flow proportions. Results indicated that BMPs implemented are not always those most suited to catchment flow pathways, and a more site-specific approach would enhance prospects for maintaining P reduction targets. Furthermore, BMP resilience to climate change can be predicted from catchment physical properties and present-day hydrochemical sensitivity to climate forcing.

  14. Microbial Decomposition of Cellulose in Acidifying Lakes of South-Central Ontario


    Hoeniger, Judith F. M.


    The rate of cellulose breakdown and density of bacterial populations were measured in the epilimnetic sediments and water columns of lakes in central Ontario that differ in pH, alkalinity, and nutrient status and are particularly sensitive to acidic inputs from atmospheric decomposition. There was no significant difference in decomposition rate in either oxic or anoxic sediment when mean epilimnetic pHs were in the range 5.5 to 6.9. The importance of these findings for the breakdown of autoch...

  15. Comparison of genetic and visual identification of cisco and lake whitefish larvae from Chaumont Bay, Lake Ontario (United States)

    George, Ellen M.; Hare, Matthew P.; Crabtree, Darran L.; Lantry, Brian F.; Rudstam, Lars G.


    Cisco Coregonus artedi are an important component of native food webs in the Great Lakes, and their restoration is instrumental to the recovery of lake trout Salvelinus namaycush and Atlantic salmon Salmo salar. Difficulties with visual identification of larvae can confound early life history surveys, as cisco are often difficult to distinguish from lake whitefish C. clupeaformis. We compared traditional visual species identification methods to genetic identifications based on barcoding of the mitochondrial cytochrome C oxidase I gene for 726 coregonine larvae caught in Chaumont Bay, Lake Ontario. We found little agreement between the visual characteristics of cisco identified by genetic barcoding and the most widely used dichotomous key, and the considerable overlap in ranges of traditionally utilized metrics suggest that visual identification of coregonine larvae from Chaumont Bay is impractical. Coregonines are highly variable and plastic species, and often display wide variations in morphometric characteristics across their broad range. This study highlights the importance of developing accurate, geographically appropriate larval identification methods in order to best inform cisco restoration and management efforts.

  16. Is reduced benthic flux related to the Diporeia decline? Analysis of spring blooms and whiting events in Lake Ontario (United States)

    Watkins, James M.; Rudstam, Lars G.; Crabtree, Darran L.; Walsh, Maureen


    Benthic monitoring by USGS off the southern shore of Lake Ontario from October 1993 to October 1995 provides a detailed view of the early stages of the decline of the native amphipod Diporeia. A loss of the 1994 and 1995 year classes of Diporeia preceded the disappearance of the native amphipod at sites near Oswego and Rochester at depths from 55 to 130 m. In succeeding years, Diporeia populations continued to decline in Lake Ontario and were nearly extirpated by 2008. Explanations for Diporeia 's decline in the Great Lakes include several hypotheses often linked to the introduction and expansion of exotic zebra and quagga mussels (Dreissena sp.). We compare the timeline of the Diporeia decline in Lake Ontario with trends in two sources of organic matter to the sediments — spring diatom blooms and late summer whiting events. The 1994–95 decline of Diporeia coincided with localized dreissenid effects on phytoplankton in the nearshore and a year (April 1994 to May 1995) of decreased flux of organic carbon recorded by sediment traps moored offshore of Oswego. Later declines of profundal (> 90 m) Diporeia populations in 2003 were poorly associated with trends in spring algal blooms and late summer whiting events. Lake Ontario/Diporeia/Dreissena/remote sensing.

  17. Feeding ecology of Brook Silverside, Golden Shiner, and Subyearling Pumpkinseed in a Lake Ontario embayment (United States)

    Johnson, James H.; Chalupnicki, Marc; Abbett, Ross; Diaz, Avriel R; Nack, Christopher C


    Fish feeding ecology has been shown to vary over a 24-h period in terms of the prey consumed and feeding intensity. Consequently, in order to best determine the interspecific feeding associations within a fish community, examination of the diet at multiple times over a 24-h period is often necessary. We examined the diel feeding ecology of three fish species that were numerically dominant in a Lake Ontario embayment during summer. The diet of each of the three species, young-of-year Pumpkinseed Lepomis gibbosus, Golden Shiner Notemigonus crysoleucas, and Brook Silverside Labidesthes sicculus, was distinct with no significant overlap in diet composition occurring within any of the 4-h time intervals. The diet composition of each species suggested that Brook Silverside were feeding at the surface (terrestrial invertebrates and aquatic surface dwelling hemipterans), whereas young-of-year Pumpkinseed (amphipods) and Golden Shiner (tipulids) were feeding on different benthic prey. Differences in feeding periodicity were most pronounced for young-of-year Pumpkinseed. Our findings provide valuable insights on interspecific feeding associations among these three fish species during summer in a Lake Ontario embayment.

  18. Headwater lake chemistry during the spring freshet in north-central Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, J.R.M.; Minns, C.K.; Lipsit, J.H.; Jeffries, D.S.


    From data on 30 headwater lakes in north-central Ontario it was found that, during the spring snow melt of 1981, all lakes underwent serious declines in alkalinity. Generally, SO/sub 4//sup 2 -/, alkalinity, Ca/sup 2 +/ and Mg/sup 2 +/ concentrations were reduced by runoff and rain then recovered to intermediate levels after the major inputs declined. As expected, a range in responses was evident with lower alkalinity systems showing the greatest changes. The observed changes, however, were consistent with acid loading having depleted alkalinity. In calculating an input-output budget for each lake, it was found that changes in Cl/sup -/, Na/sup +/, and K/sup +/ were consistent with atmospheric inputs being the major source as the difference between the expected input and the actual contribution from rain and snow had a mean near zero. There appears to be a significant, approximately equal to 45%, watershed source of sulfate that the authors hypothesize is from dry deposition occurring prior to snowfall and is eluted with the melting process. With refinements to a mass balance approach explaining the watershed source of SO/sub 4//sup 2 -/ and Al, it is possible to predict springtime lake changes given a few chemical and simple morphometric variables.

  19. Regional trends in evaporation loss and water yield based on stable isotope mass balance of lakes: The Ontario Precambrian Shield surveys (United States)

    Gibson, J. J.; Birks, S. J.; Jeffries, D.; Yi, Y.


    Stable isotopes of water, oxygen-18 and deuterium, were measured in water samples collected from a network of 300 lakes sampled in six ∼100 km2 blocks (centred at 49.72°N, 91.46°W; 48.49°N, 91.58°W; 50.25°N, 86.62°W; 49.78°N, 83.98°W; 48.24°N, 85.49°W; 47.73, 84.52°W) within Precambrian shield drainages in the vicinity of Lake Superior, northern Ontario, Canada. Additional sampling was also conducted within the Turkey Lakes watershed (47.03°N, 84.38°W), a research basin situated in the Algoma region located 50 km north of Sault Saint Marie, Ontario. The studies were undertaken to gain a better understanding of hydrology and geochemistry of watersheds in the region in order to better predict acid sensitivity of lakes. The main objective of this paper is to describe the hydrologic variations observed based on stable isotope results. Evaporative isotopic enrichment of lake water was found to be systematic across the region, and its deviation from the isotopic composition of precipitation was used to estimate the evaporation/inflow to the lakes as well as runoff (or water yield) based on a simple isotope mass balance model. The analysis illustrates significant variability in the water yield to lakes and reveals a pattern of positively skewed distributions in all six widely spaced blocks, suggesting that a high proportion of lakes have relatively limited runoff whereas relatively few have greater runoff. Such basic information on the drainage structure of an area can be valuable for site-specific hydrologic assessments but also has significant implications for critical loads assessment, as low runoff systems tend to be less buffered and therefore are more sensitive to acidification. Importantly, the Turkey Lakes sampling program also suggests that isotope-based water yield is comparable in magnitude to hydrometric gauging estimates, and also establishes that uncertainty related to stratification can be as high as ±20% or more for individual lakes

  20. Hydroacoustic measures of Mysis relicta abundance and distribution in Lake Ontario (United States)

    Rudstam, L. G.; Schaner, T.; Gal, G.; Boscarino, B.T.; O'Gorman, R.; Warner, D.M.; Johannsson, O.E.; Bowen, K.L.


    Mysis relicta can be observed on echograms as a sound scattering layer when they migrate into the water column at night to feed on zooplankton. However, quantitative measures of mysid abundance with hydroacoustics requires knowledge of mysid target strength (TS), a method of removing fish echoes and contribution from noise, and an understanding of the effect of range on the ability of hydroacoustics to detect mysids (the detection limit). Comparisons of paired net data and acoustics data from July 7, 2005 yielded a mysid TS of -86.3 dB (9 mm animal) and a biomass TS of -58.4 dB (g dry wt)-1. With ambient noise levels (Sv of -125 dB at 1 m depth) and this TS, we can detect a mysid density of 1 m-3 at 60 m depth with a signal to noise ratio of 3 dB. We present a method to remove backscattering from both noise and fish and apply this method and the new TS data to whole lake acoustic data from Lake Ontario collected in July 25-31, 2005 with a 120 kHz echosounder as part of the annual standard fish survey in that lake. Mysis abundance was strongly depth dependent, with highest densities in areas with bottom depth > 100 m, and few mysids in areas with bottom depth 100 m, 100-75 m, 75-50 m, 50-30 m, < 30 m), the whole-lake average mysid density was 118 m-2 (CV 21%) and the whole-lake average mysid biomass was 0.19 g dry wt m-2 (CV 22%) in July 2005. The CVs of these densities also account for uncertainty in the TS estimates. This is comparable to whole-lake density estimates using vertical net tows in November, 2005 (93 m-2, CV 16%). Copyright ?? 2008 AEHMS.

  1. Phytochemistry of plants associated with a 400-year-old stand of hemlock at Clear Lake Reserve, Ontario (United States)

    A. M. Zobel; K. Glowniak; J. E. Lynch; S. Dudka; A. Alliota


    Several species of higher plants and mushrooms have been surveyed growing under the canopy of old stands of hemlock surrounding Clear Lake near Minden, Ontario. Some of the hemlock seedlings growing on fallen trunks together with debris in which they were growing were brought to a greenhouse in pots, and some of them were transferred into sandy soil. The conditions of...

  2. 78 FR 40260 - International Joint Commission: Public Comment on a Proposal for Lake Ontario and St. Lawrence... (United States)


    ... International Joint Commission: Public Comment on a Proposal for Lake Ontario and St. Lawrence River Regulation The International Joint Commission (IJC) is inviting the public to comment on a proposal for managing... be included in the record of public comment. The International Joint Commission was established under...

  3. Competency assessment of microbiology medical laboratory technologists in Ontario, Canada. (United States)

    Desjardins, Marc; Fleming, Christine Ann


    Accreditation in Ontario, Canada, requires that licensed clinical laboratories participate in external quality assessment (also known as proficiency testing) and perform competency evaluation of their staff. To assess the extent of ongoing competency assessment practices, the Quality Management Program--Laboratory Services (QMP-LS) Microbiology Committee surveyed all 112 licensed Ontario microbiology laboratories. The questionnaire consisted of a total of 21 questions that included yes/no, multiple-choice, and short-answer formats. Participants were asked to provide information about existing programs, the frequency of testing, what areas are evaluated, and how results are communicated to the staff. Of the 111 responding laboratories, 6 indicated they did not have a formal evaluation program since they perform only limited bacteriology testing. Of the remaining 105 respondents, 87% perform evaluations at least annually or every 2 years, and 61% include any test or task performed, whereas 16% and 10% focus only on problem areas and high-volume complex tasks, respectively. The most common methods of evaluation were review of external quality assessment (EQA) challenges, direct observation, and worksheet review. With the exception of one participant, all communicate results to staff, and most take remedial action to correct the deficiencies. Although most accredited laboratories have a program to assess the ongoing competency of their staff, the methods used are not standardized or consistently applied, indicating that there is room for improvement. The survey successfully highlighted potential areas for improvement and allowed the QMP-LS Microbiology Committee to provide guidance to Ontario laboratories for establishing or improving existing microbiology-specific competency assessment programs. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Competency Assessment of Microbiology Medical Laboratory Technologists in Ontario, Canada (United States)

    Fleming, Christine Ann


    Accreditation in Ontario, Canada, requires that licensed clinical laboratories participate in external quality assessment (also known as proficiency testing) and perform competency evaluation of their staff. To assess the extent of ongoing competency assessment practices, the Quality Management Program—Laboratory Services (QMP-LS) Microbiology Committee surveyed all 112 licensed Ontario microbiology laboratories. The questionnaire consisted of a total of 21 questions that included yes/no, multiple-choice, and short-answer formats. Participants were asked to provide information about existing programs, the frequency of testing, what areas are evaluated, and how results are communicated to the staff. Of the 111 responding laboratories, 6 indicated they did not have a formal evaluation program since they perform only limited bacteriology testing. Of the remaining 105 respondents, 87% perform evaluations at least annually or every 2 years, and 61% include any test or task performed, whereas 16% and 10% focus only on problem areas and high-volume complex tasks, respectively. The most common methods of evaluation were review of external quality assessment (EQA) challenges, direct observation, and worksheet review. With the exception of one participant, all communicate results to staff, and most take remedial action to correct the deficiencies. Although most accredited laboratories have a program to assess the ongoing competency of their staff, the methods used are not standardized or consistently applied, indicating that there is room for improvement. The survey successfully highlighted potential areas for improvement and allowed the QMP-LS Microbiology Committee to provide guidance to Ontario laboratories for establishing or improving existing microbiology-specific competency assessment programs. PMID:24899030

  5. The deep chlorophyll layer in Lake Ontario: Extent, mechanisms of formation, and abiotic predictors (United States)

    Scofield, Anne E.; Watkins, James M.; Weidel, Brian C.; Luckey, Frederick J.; Rudstam, Lars G.


    Epilimnetic production has declined in Lake Ontario, but increased production in metalimnetic deep chlorophyll layers (DCLs) may compensate for these losses. We investigated the spatial and temporal extent of DCLs, the mechanisms driving DCL formation, and the use of physical variables for predicting the depth and concentration of the deep chlorophyll maximum (DCM) during April–September 2013. A DCL with DCM concentrations 2 to 3 times greater than those in the epilimnion was present when the euphotic depth extended below the epilimnion, which occurred primarily from late June through mid-August. In situ growth was important for DCL formation in June and July, but settling and photoadaptation likely also contributed to the later-season DCL. Supporting evidence includes: phytoplankton biovolume was 2.4 × greater in the DCL than in the epilimnion during July, the DCL phytoplankton community of July was different from that of May and the July epilimnion (p = 0.004), and there were concurrences of DCM with maxima in fine particle concentration and dissolved oxygen saturation. Higher nutrient levels in the metalimnion may also be a necessary condition for DCL formation because July metalimnetic concentrations were 1.5 × (nitrate) and 3.5 × (silica) greater than in the epilimnion. Thermal structure variables including epilimnion depth, thermocline depth, and thermocline steepness were useful for predicting DCM depth; the inclusion of euphotic depth only marginally improved these predictions. However, euphotic depth was critical for predicting DCM concentrations. The DCL is a productive and predictable feature of the Lake Ontario ecosystem during the stratified period.

  6. Status of important prey fishes in the U.S. Waters of Lake Ontario, 2013: Introduction and Methods, Alewife, Rainbow Smelt, Sculpins, and Round Goby (United States)

    Walsh, Maureen; Weidel, Brian C.; Connerton, Michael J.


    The 2013 benthic fish assessment was delayed and shortened as a result of the U.S. Government shutdown, however the assessment collected 51 of the 62 planned bottom trawls. Over the past 34 years, Slimy Sculpin abundance in Lake Ontario has fluctuated, but ultimately decreased by two orders of magnitude, with a substantial decline occurring in the past 10 years. The 2013 Slimy Sculpin mean bottom trawl catch density (0.001 ind.·m-2, s.d.= 0.0017, n = 52) and mean biomass density (0.015 g·m-2 , s.d.= 0.038, n = 52) were the lowest recorded in the 27 years of sampling using the original bottom trawl design. From 2011-2013, the Slimy Sculpin density and biomass density has decreased by approximately 50% each year. Spring bottom trawl catches illustrate Slimy Sculpin and Round Goby Neogobius melanostoma winter habitat overlaps for as much as 7 months out of a year, providing opportunities for competition and predation. Invasive species, salmonid piscivory, and declines in native benthic invertebrates are likely all important drivers of Slimy Sculpin population dynamics in Lake Ontario. Deepwater Sculpin Myoxocephalus thompsonii, considered rare or absent from Lake Ontario for 30 years, have generally increased over the past eight years. For the first time since they were caught in this assessment, Deepwater Sculpin density and biomass density estimates declined from the previous year. The 2013 abundance and density estimates for trawls covering the standard depths from 60m to 150m was 0.0001 fish per square meter and 0.0028 grams per square meter. In 2013, very few small (< 80 mm) Deepwater Sculpin were caught and most sculpin were at sites of 150 meters or greater, which is in contrast to previous years when juvenile fish were caught around 80-100 meters. The reduced effort and late seasonal timing of the 2013 assessment make it difficult to have high confidence in declines observed in 2013, however observed Alewife Alosa psuedoharengus abundance increases and

  7. Integrative analysis of the Lake Simcoe watershed (Ontario, Canada) as a socio-ecological system. (United States)

    Neumann, Alex; Kim, Dong-Kyun; Perhar, Gurbir; Arhonditsis, George B


    Striving for long-term sustainability in catchments dominated by human activities requires development of interdisciplinary research methods to account for the interplay between environmental concerns and socio-economic pressures. In this study, we present an integrative analysis of the Lake Simcoe watershed, Ontario, Canada, as viewed from the perspective of a socio-ecological system. Key features of our analysis are (i) the equally weighted consideration of environmental attributes with socioeconomic priorities and (ii) the identification of the minimal number of key socio-hydrological variables that should be included in a parsimonious watershed management framework, aiming to establish linkages between urbanization trends and nutrient export. Drawing parallels with the concept of Hydrological Response Units, we used Self-Organizing Mapping to delineate spatial organizations with similar socio-economic and environmental attributes, also referred to as Socio-Environmental Management Units (SEMUs). Our analysis provides evidence of two SEMUs with contrasting features, the "undisturbed" and "anthropogenically-influenced", within the Lake Simcoe watershed. The "undisturbed" cluster occupies approximately half of the Lake Simcoe catchment (45%) and is characterized by low landscape diversity and low average population density <0.4 humans ha-1. By contrast, the socio-environmental functional properties of the "anthropogenically-influenced" cluster highlight the likelihood of a stability loss in the long-run, as inferred from the distinct signature of urbanization activities on the tributary nutrient export, and the loss of subwatershed sensitivity to natural mechanisms that may ameliorate the degradation patterns. Our study also examines how the SEMU concept can augment the contemporary integrated watershed management practices and provides directions in order to promote environmental programs for lake conservation and to increase public awareness and engagement in

  8. Habitat use by juvenile salmonids in Lake Ontario tributaries-species, age, diel and seasonal effects (United States)

    Johnson, James H.; McKenna, James E.


    Understanding the habitat needs of fish and how these requirements may change seasonally over a 24-h period is important, especially for highly managed sport species. Consequently, we examined the diel and seasonal habitat use of four juvenile salmonid species in streams in the Lake Ontario watershed. For juvenile Atlantic salmon Salmo salarand juvenile rainbow trout Oncorhynchus mykiss, differences in day versus night habitat use were more profound than seasonal differences. Observed differences in day versus night habitat for all species and age classes were mainly due to the use of less object oriented cover at night and to a lesser extent to the use of slower velocities and smaller substrate at night. Seasonal differences in habitat use were also observed, likely due to increased fish size, and included movement to deeper and faster water and the use of larger substrate and more cover from summer to winter. Different habitat variables were important to individual species. Juvenile Atlantic salmon were associated with higher water velocities, juvenile rainbow trout with larger substrate and more cover, and subyearling Chinook salmon O. tshawytscha and subyearling coho salmon O. kisutch with small substrate and less cover. Our observations demonstrate that habitat partitioning occurs and likely reduces intraspecific and interspecific competition which may increase the potential production of all four species in sympatry. Consequently, these findings provide important information for resource managers charged with managing, protecting, and enhancing Great Lakes tributaries where all or some of these species occur.

  9. The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

    Directory of Open Access Journals (Sweden)

    S. A. Watmough


    Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

  10. Disruption of the lower food web in Lake Ontario: Did it affect alewife growth or condition? (United States)

    O'Gorman, R.; Prindle, S.E.; Lantry, J.R.; Lantry, B.F.


    From the early 1980s to the late 1990s, a succession of non-native invertebrates colonized Lake Ontario and the suite of consequences caused by their colonization became known as "food web disruption". For example, the native burrowing amphipod Diporeia spp., a key link in the profundal food web, declined to near absence, exotic predaceous cladocerans with long spines proliferated, altering the zooplankton community, and depth distributions of fishes shifted. These changes had the potential to affect growth and condition of planktivorous alewife Alosa pseudoharengus, the most abundant fish in the lake. To determine if food web disruption affected alewife, we used change-point analysis to examine alewife growth and adult alewife condition during 1976-2006 and analysis-of-variance to determine if values between change points differed significantly. There were no change points in growth during the first year of life. Of three change points in growth during the second year of life, one coincided with the shift in springtime distribution of alewife to deeper water but it was not associated with a significant change in growth. After the second year of life, no change points in growth were evident, although growth in the third year of life spiked in those years when Bythotrephes, the largest of the exotic cladocerans, was abundant suggesting that it was a profitable prey item for age-2 fish. We detected two change points in condition of adult alewife in fall, but the first occurred in 1981, well before disruption began. A second change point occurred in 2003, well after disruption began. After the springtime distribution of alewife shifted deeper during 1992-1994, growth in the first two years of life became more variable, and growth in years of life two and older became correlated (P < 0.05). In conclusion, food web disruption had no negative affect on growth and condition of alewife in Lake Ontario although it appears to have resulted in growth in the first two years of

  11. Environmental Monitoring, Water Quality - Lakes Assessments - Attaining (United States)

    NSGIC Education | GIS Inventory — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  12. Geology, geochemistry, and geochronology of the East Bay gold trend, Red Lake, Ontario, Canada (United States)

    Gallagher, Shaun; Camacho, Alfredo; Fayek, Mostafa; Epp, Mark; Spell, Terry L.; Armstrong, Richard


    The Red Lake greenstone belt is situated in northwestern Ontario within the Uchi Subprovince, Superior Province. Most gold deposits therein are associated with major deformation corridors; the east-west oriented "Mine trend" hosts most of the large deposits and the northeast-southwest "East Bay trend" hosts several small deposits and showings. Gold along the East Bay trend typically occurs in quartz replacement veins that were emplaced into pre-existing quartz-carbonate veins. Gold can occur as free gold or along vein margins associated with pyrite and pyrrhotite. Most primary fluid inclusions, preserved in relatively undeformed portions of veins, are carbonaceous with lesser quantities of aqueous inclusions. The average homogenization temperature of aqueous fluids is 250 °C; however, the abundance of three-phase inclusions, variation in liquid-vapor ratios, and a wide range in homogenization temperatures indicate that immiscibility, effervescence, and fluid mixing are mechanisms associated with gold deposition. The age ( 2550 Ma) of alteration minerals in the Abino area is considerably younger (by 100 Myr) than alteration minerals in other deposits in the Red Lake district, indicating that the mineralizing fluid history was more protracted than previously thought. Along the East Bay trend, barren veins generally have lower δ18OVSMOW values (0.0 to 8.5‰) relative to auriferous veins (9.6 and 13.1‰). Consequently, the oxygen isotopic composition of quartz could be used as a vector for gold mineralization. The genetic model for the East Bay trend involves several stages of vein formation. Auriferous veins formed near the upper boundary of the mesozonal regime (depth of 5-6 km).

  13. Habitat use and diet composition of juvenile Atlantic salmon in a tributary of Lake Ontario (United States)

    Johnson, James H.


    The habitat use and diet of juvenile Atlantic salmon Salmo salar was examined in the South Sandy Creek drainage that discharges into eastern Lake Ontario. Subyearling salmon were stocked in early May during two consecutive years, and habitat and diet evaluations were made in mid-July and mid-October in 2005 and 2006. Both subyearling and yearling Atlantic salmon occupied deeper and faster areas that had more cover and larger sized substrate materials than was present, on average, within the study reach. Differences in habitat use between subyearling and yearling salmon only occurred in summer. Principal component analysis showed that of the habitat variables examined, the amount of cover and size of substrate were more important to juvenile salmon in summer, whereas depth and velocity were more important in the fall. Trichopteran larvae (mainly hydropsychids) dominated the diet of juvenile Atlantic salmon, and parr were feeding most heavily from the substrate as compared to the drift. The juvenile ecology of this re-introduced population of Atlantic salmon is consistent with that reported in other studies throughout the species native range.

  14. Lakewide estimates of alewife biomass and Chinook salmon abundance and consumption in Lake Ontario, 1989–2005: implications for prey fish sustainability (United States)

    Murry, Brent A.; Connerton, Michael J.; O'Gorman, Robert; Stewart, Donald J.; Ringlerd, Neil H.


    Stocking levels of Chinook salmon Oncorhynchus tshawytscha for Lake Ontario have been highly controversial since the early 1990s, largely because of uncertainties about lakewide abundance and rates of prey consumption. Previous estimates have focused on years before 1995; since then, however, the Lake Ontario ecosystem has undergone substantial changes, and there is new evidence of extensive natural recruitment. Presented here are new abundance estimates of Chinook salmon and alewives Alosa pseudoharengus in Lake Ontario and a reevaluation of the potential risk of alewife population collapse. We found that Lake Ontario has been supporting, on average (1989–2005), 1.83 × 106 (range, 1.08 × 106 to 3.24 × 106) Chinook salmon of ages 1–4, amounting to a mean annual biomass of 11.33 × 103 metric tons (range, 5.83 × 103 to 23.04 × 103 metric tons). During the same period (1989–2005), the lake supported an alewife biomass of 173.66 × 103 metric tons (range, 62.37 × 103 to 345.49 × 103 metric tons); Chinook salmon of ages 1–4 consumed, on average, 22% (range, 11–44%) of the alewife biomass annually. Because our estimates probably underestimate total consumption and because Chinook salmon are only one of several salmonine species that depend on alewives, predation pressure on the Lake Ontario alewife population may be high enough to raise concerns about long-term stability of this predator–prey system.

  15. Historical and anthropogenic factors affecting the population genetic structure of Ontario's inland lake populations of Walleye (Sander vitreus). (United States)

    Walter, Ryan P; Cena, Christopher J; Morgan, George E; Heath, Daniel D


    Populations existing in formerly glaciated areas often display composite historical and contemporary patterns of genetic structure. For Canadian freshwater fishes, population genetic structure is largely reflective of dispersal from glacial refugia and isolation within drainage basins across a range of scales. Enhancement of sport fisheries via hatchery stocking programs and other means has the potential to alter signatures of natural evolutionary processes. Using 11 microsatellite loci genotyped from 2182 individuals, we analyzed the genetic structure of 46 inland lake walleye (Sander vitreus) populations spanning five major drainage basins within the province of Ontario, Canada. Population genetic analyses coupled with genotype assignment allowed us to: 1) characterize broad- and fine-scale genetic structure among Ontario walleye populations; and 2) determine if the observed population divergence is primarily due to natural or historical processes, or recent anthropogenic events. The partitioning of genetic variation revealed higher genetic divergence among lakes than among drainage basins or proposed ancestries-indicative of relatively high isolation among lakes, study-wide. Walleye genotypes were clustered into three major groups, likely reflective of Missourian, Mississippian, and Atlantic glacial refugial ancestry. Despite detectable genetic signatures indicative of anthropogenic influences, province-wide spatial genetic structure remains consistent with the hypothesis of dispersal from distinct glacial refugia and subsequent isolation of lakes within primary drainage basins. Our results provide a novel example of minimal impacts from fishery enhancement to the broad-scale genetic structure of inland fish populations.

  16. Acoustic architecture of glaciolacustrine sediments deformed during zonal stagnation of the Laurentide Ice Sheet; Mazinaw Lake, Ontario, Canada (United States)

    Eyles, Nicholas; Doughty, Mike; Boyce, Joseph I.; Mullins, Henry T.; Halfman, John D.; Koseoglu, Berkant


    In North America, the last (Laurentide) Ice Sheet retreated from much of the Canadian Shield by 'zonal stagnation'. Masses of dead ice, severed from the main ice sheet by emerging bedrock highs, downwasted in situ within valleys and lake basins and were commonly buried by sediment. Consequently, the flat sediment floors of many valleys and lakes are now pitted by steep-sided, enclosed depressions (kettle basins) that record the melt of stagnant ice blocks and collapse of sediment. At Mazinaw Lake in eastern Ontario, Canada, high-resolution seismic reflection, magnetic and bathymetric surveys, integrated with onland outcrop and hammer seismic investigations, were conducted to identify the types of structural disturbance associated with the formation of kettle basins in glaciolacustrine sediments. Basins formed as a result of ice blocks being trapped within a regionally extensive proglacial lake (Glacial Lake Iroquois ˜12,500 to 11,400 years BP) that flooded eastern Ontario during deglaciation. Kettles occur within a thick (>30 m) succession of parallel, high-frequency acoustic facies consisting of rhythmically laminated (varved?) Iroquois silty-clays. Iroquois strata underlying and surrounding kettle basins show large-scale normal faults, fractures, rotational failures and incoherent chaotically bedded sediment formed by slumping and collapse. Mazinaw Lake lies along part of the Ottawa Graben and while neotectonic earthquake activity cannot be entirely dismissed, deformation is most likely to have occurred as a result of the rapid melt of buried ice blocks. Seismic data do not fully penetrate the entire basin sediment fill but the structure and topography of bedrock can be inferred from magnetometer data. The location and shape of buried ice masses was closely controlled by the graben-like form of the underlying bedrock surface.

  17. Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada


    Martha Patricia Celis-Salgado; Wendel Keller; Yan, Norman D.


    Smelting of sulphur-rich metallic ores in Sudbury, Ontario, Canada, has caused acidification and metal contamination of thousands of lakes in the region. Recent reductions in smelter emissions have resulted in much ecological recovery, but the recovery of Daphnia species has been poor. To determine if Cu and Ni toxicity could explain differences in daphniid recovery among lakes, we compared results of 14 d static with renewal bioassays in waters from Blue Chalk Lake, an uncontaminated referen...

  18. An Assessment of the Utilization of Diagnostic Parasitology Laboratory Services in Ontario

    Directory of Open Access Journals (Sweden)

    Harold Richardson


    Full Text Available OBJECTIVE: Diagnostic parasitology services in Ontario were assessed to determine whether the reduction in the number of provider laboratories from 209 to 70 over the period 1977 to 1994 has affected the availability and quality of service.

  19. Comparison of diets for Largemouth and Smallmouth Bass in Eastern Lake Ontario using DNA barcoding and stable isotope analysis. (United States)

    Nelson, Erich J H; Holden, Jeremy; Eves, Robert; Tufts, Bruce


    Largemouth (LMB: Micropterus salmoides) and Smallmouth Bass (SMB: Micropterus dolomieu) are important species in the recreational fisheries of the Laurentian Great Lakes. The invasion of the Round Goby (Neogobius melanostomus) into these lakes has changed several facets of black bass biology, but there is still much to learn about the relationship between these species. Previous dietary analyses have shown Round Goby to be important prey for bass, but have been limited by low visual identification rates of dissected stomach items. Within the present study, DNA barcoding and stable isotope analysis improve prey identification and provide a more quantitative dietary analysis of adult black bass in Lake Ontario, comparing the importance of Round Goby as prey between these two species. Eighty-four LMB (406mm fork length ±4mm SEM) and two hundred sixty-four SMB (422mm ±2mm) obtained as tournament mortalities had prey identified using DNA-based methods. Round Goby was the most prevalent prey species for both predators. The diet of LMB was three times more diverse than that of SMB, which almost entirely consists of Round Goby. Our results provide further support that recent increases in the size of Lake Ontario bass are a result of Round Goby consumption, and that the effects of this dietary shift on body condition are greater for SMB. Techniques developed in this study include reverse-oriented dual priming oligonucleotides used as blocking primers for predator DNA, and an automated design approach of restriction fragment length polymorphism tests for identifying prey DNA barcodes.

  20. Comparison of diets for Largemouth and Smallmouth Bass in Eastern Lake Ontario using DNA barcoding and stable isotope analysis (United States)

    Holden, Jeremy; Eves, Robert; Tufts, Bruce


    Largemouth (LMB: Micropterus salmoides) and Smallmouth Bass (SMB: Micropterus dolomieu) are important species in the recreational fisheries of the Laurentian Great Lakes. The invasion of the Round Goby (Neogobius melanostomus) into these lakes has changed several facets of black bass biology, but there is still much to learn about the relationship between these species. Previous dietary analyses have shown Round Goby to be important prey for bass, but have been limited by low visual identification rates of dissected stomach items. Within the present study, DNA barcoding and stable isotope analysis improve prey identification and provide a more quantitative dietary analysis of adult black bass in Lake Ontario, comparing the importance of Round Goby as prey between these two species. Eighty-four LMB (406mm fork length ±4mm SEM) and two hundred sixty-four SMB (422mm ±2mm) obtained as tournament mortalities had prey identified using DNA-based methods. Round Goby was the most prevalent prey species for both predators. The diet of LMB was three times more diverse than that of SMB, which almost entirely consists of Round Goby. Our results provide further support that recent increases in the size of Lake Ontario bass are a result of Round Goby consumption, and that the effects of this dietary shift on body condition are greater for SMB. Techniques developed in this study include reverse-oriented dual priming oligonucleotides used as blocking primers for predator DNA, and an automated design approach of restriction fragment length polymorphism tests for identifying prey DNA barcodes. PMID:28771612

  1. Sustainability of hatchery-dependent salmonine fisheries in Lake Ontario: The conflict between predator demand and predator supply (United States)

    Jones, Michael L.; Koonce, Joseph F.; O'Gorman, Robert


    The offshore fish community of Lake Ontario is presently dominated by intensively managed, nonnative species: Alewife Alosa pseudoharengus and rainbow smelt Osmerus mordax at the planktivore level and stocked salmonines at the piscivore level. Salmonine stocking rates per unit area of Lake Ontario are the highest in the Great Lakes, and fishery managers are concerned about the sustainability of the fishery under present stocking policies, particularly with the recent collapse of the Lake Michigan fishery for chinook salmon Oncorhynchus tshawytscha. In this paper, we describe and present the results of a simulation model that integrates predator demand estimates derived from bioenergetics, prey and predator population dynamics, and a predation model based on the multiple-species functional response, Model reconstructions of historical alewife biomass trends and salmonine diets corresponded reasonably well with existing data for the period 1978–1992. The simulations suggest that current predator demand does not exceed the threshold beyond which alewife biomass cannot be sustained, but they indicate that the sustainability of the prey fish community is extremely sensitive to fluctuations in overwinter survival of alewife; an additional mortality of 25% in a single winter would be sufficient to cause the collapse of the alewife population. The model includes a number of assumptions and simplifications with a limited empirical basis; better estimates of salmonine survival rates, an evaluation of the importance of spatial and temporal interactions among predators and prey, and incorporation of the effects of recently observed declines in system productivity at lower trophic levels would significantly increase confidence in the model's projections.

  2. Groundwater quality in the Eastern Lake Ontario Basin of New York, 2008 (United States)

    Risen, Amy J.; Reddy, James E.


    Water samples were collected from nine production wells and nine private residential wells in the Eastern Lake Ontario Basin of New York from August through October 2008 and analyzed to characterize the chemical quality of groundwater. The wells were selected to provide adequate spatial coverage of the 3,225-square-mile study area; areas of greatest groundwater use were emphasized. Eight of the 18 wells sampled, were screened in sand and gravel aquifers, and 10 were finished in bedrock aquifers. The samples were collected and processed by standard U.S. Geological Survey procedures and were analyzed for 223 physical properties and constituents, including major ions, nutrients, trace elements, radon-222, pesticides, volatile organic compounds (VOCs), and indicator bacteria. Water quality in the study area is generally good, but concentrations of some constituents exceeded current or proposed Federal or New York State drinking-water standards; these were: color (2 samples), pH (1 sample), sodium (5 samples), chloride (1 sample), aluminum (2 samples), iron (5 unfiltered samples), manganese (3 samples), radon-222 (13 samples), and bacteria (4 samples). Dissolved-oxygen concentrations in samples from wells finished in sand and gravel [median 3.8 milligrams per liter (mg/L)] were greater than those from wells finished in bedrock (median less than 0.7 mg/L). The pH of all samples was typically neutral or slightly basic (median 7.4); the median water temperature was 11.3 degrees Celsius. The ions with the highest concentrations were bicarbonate (median 174 mg/L) and calcium (median 24.1 mg/L). Groundwater in the basin ranges from soft to moderately hard [less than or equal to 120 mg/L as CaCO3] and median hardness was 90 mg/L as CaCO3. Concentrations of nitrate plus nitrite in samples from sand and gravel wells (median concentration 0.42 mg/L as nitrogen) were generally higher than those in samples from bedrock wells (median coliform bacteria were detected in 3 samples, and

  3. Feasibility Study of Shoreline Protection and Lake Level Regulation for Lake Ontario. Reconnaissance Report. Volume I. Main Report. (United States)


    trout popula- tions are expected to rebound due to sea lamprey control efforts and impor- tant ongoing lake trout restocking programs. Wildlife...protecting the shores of property on the Atlantic and Pacific Oceans, the Gulf of Mexico, the Great Lakes, and lakes, estuaries, and bays, directly connected

  4. Library-dependent and library-independent microbial source tracking to identify spatial variation in faecal contamination sources along a Lake Ontario beach (Ontario, Canada). (United States)

    Edge, T A; Hill, S; Seto, P; Marsalek, J


    Multiple microbial source tracking methods were applied to investigate spatial variation in faecal pollution sources impacting a 1.7 km freshwater beach on Lake Ontario (Canada). The highest E. coli concentrations measured in the study area were from interstitial sand pore water at Sunnyside Beach, reaching 2.6 x 10(6) CFU/100 ml. These E. coli concentrations exceeded those in the nearby Humber River and Black Creek, which are impacted by combined sewer overflows containing municipal wastewater and by stormwater conveying washoff from the urban area. Library-independent Bacteroidales HF183 analyses identified the more frequent occurrence of municipal wastewater contamination in the Humber River and at a Sunnyside Beach location closest to the mouth of the river. Library-dependent E. coli antibiotic resistance and rep-PCR DNA fingerprinting analyses identified the more frequent occurrence of bird faecal contamination at Sunnyside Beach locations away from the river mouth. These microbial source tracking results raise caution about managing beaches with multiple sources of contamination as a single entity without considering spatial variability in faecal pollution sources and the need for more localized beach management practices.

  5. Ontario protocol assessment level: clinical trial complexity rating tool for workload planning in oncology clinical trials. (United States)

    Smuck, Bobbi; Bettello, Phyllis; Berghout, Koralee; Hanna, Tracie; Kowaleski, Brenda; Phippard, Lynda; Au, Diana; Friel, Kay


    The Ontario Institute for Cancer Research supported the creation of a working group with the objective of developing a standard rating scale to evaluate clinical trial complexity and applying the scale to facilitate workload measurement for Ontario cancer research sites. The lack of a mechanism to measure the workload involved in a clinical trials protocol was identified and confirmed by a literature review. To collect information on how Ontario sites were assessing workload, a survey was distributed and evaluated. As a result, the working group developed the Ontario Protocol Assessment Level (OPAL), a protocol complexity rating scale designed to capture the workload involved in a clinical trial. After a training workshop on the application, OPAL was evaluated by 17 Ontario cancer centers to demonstrate its reliability and consistency during a 3-month pilot study. Twenty-seven protocols were reviewed by multiple sites, and the majority of the sites reported OPAL score differences between 0 and 1.5. OPAL provides clinical trials departments with an objective method of quantifying clinical trials activity on the basis of study protocol complexity. With consistent application of OPAL, sites can manage staffing objectively. The working group is continuing to monitor the application of OPAL in Ontario.

  6. Fish community structure, biomass, and production in the Turkey Lakes Watershed, Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, J.R.M. (Great Lakes Laboratory for Fisheries and Aquatic Sciences, Sault Ste. Marie, ON (Canada))


    Lake acidification affects fish community structure; however, a wide variety of biogeographic factors are also known to strongly influence fish community. The Turkey Lakes Watershed contains four lakes, and the headwater lake (Batchawana Lake) consists of two distinct basins, neither of which supports a native, reproducing fish stock. The abundance, standing stock, and production of fish prone to sampling with a diversity of capture gear in the Turkey Lakes system was estimated to evaluate the relative influence of lake chemistry and physical habitat upon the community and its performance, as measured by fish flesh production. Total fish biomass varied by a factor of 3.3 and total fish flesh production by a factor of only 1.5 within the watershed. Both fish biomass and production per unit surface area decreased with increasing lake depth. The fish biomass and production decreased with progression downstream. Within the watershed, however, salmonids and cyprinid contribution to biomass and production increased with progression downstream. It is unclear whether the status of the fish community in the Turkey Lakes Watershed results from lake acidification or biogeographic factors. 21 refs., 2 figs., 5 tabs.

  7. Predation on Pacific salmonid eggs and carcass's by subyearling Atlantic salmon in a tributary of Lake Ontario (United States)

    Johnson, James H.; Chalupnicki, Marc A.; Abbett, Ross; Verdoliva, Francis


    A binational effort to reintroduce Atlantic salmon (Salmo salar) that were extirpated in the Lake Ontario ecosystem for over a century is currently being undertaken by the New York State Department of Environmental Conservation and the Ontario Ministry of Natural Resources. Reintroduction actions include the release of several life stages including fry, fall fingerlings, and yearling smolts. In this study we describe the diet of recently released fall fingerling Atlantic salmon in a tributary of the Salmon River, New York. A specific objective of the study was to determine if juvenile Atlantic salmon would utilize the high caloric food source provided by introduced Pacific salmonids (Oncorhynchus spp.) that includes eggs and carcass flesh. Salmon eggs and carcass flesh comprised 20.5% of the October to January diet in 2013–14 and 23.9% in 2014–15. The consumption of steelhead (O. mykiss) eggs was a major part of the diet in April in both 2014 (54.1%) and 2015 (33.2%). This study documented that recently released Atlantic salmon will consume the high caloric food material provided by Pacific salmonids and that the consumption of this material extends for several months.

  8. Groundwater quality in the Chemung River, Eastern Lake Ontario, and Lower Hudson River Basins, New York, 2013 (United States)

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


    In a study conducted by the U.S. Geological Survey (USGS) in cooperation with the New York State Department of Environmental Conservation, water samples were collected from 4 production wells and 4 domestic wells in the Chemung River Basin, 8 production wells and 7 domestic wells in the Eastern Lake Ontario Basin, and 12 production wells and 13 domestic wells in the Lower Hudson River Basin (south of the Federal Lock and Dam at Troy) in New York. All samples were collected in June, July, and August 2013 to characterize groundwater quality in these basins. The samples were collected and processed using standard USGS procedures 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.

  9. A Review of (Elementary) School Self-Assessment Processes: Ontario and Beyond (United States)

    Ryan, Thomas G.; Telfer, Leslie


    This review draws attention to issues related to school self-assessment. This process has been similarly implemented in a variety of jurisdictions globally in the past decade hence their inclusion herein as an attempt to understand the school self-assessment process which has also been developed for use in local Ontario (Canadian) elementary…

  10. Comparing health system performance assessment and management approaches in the Netherlands and Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Klazinga Niek S


    Full Text Available Abstract Background Given the proliferation and the growing complexity of performance measurement initiatives in many health systems, the Netherlands and Ontario, Canada expressed interests in cross-national comparisons in an effort to promote knowledge transfer and best practise. To support this cross-national learning, a study was undertaken to compare health system performance approaches in The Netherlands with Ontario, Canada. Methods We explored the performance assessment framework and system of each constituency, the embeddedness of performance data in management and policy processes, and the interrelationships between the frameworks. Methods used included analysing governmental strategic planning and policy documents, literature and internet searches, comparative descriptive tables, and schematics. Data collection and analysis took place in Ontario and The Netherlands. A workshop to validate and discuss the findings was conducted in Toronto, adding important insights to the study. Results Both Ontario and The Netherlands conceive health system performance within supportive frameworks. However they differ in their assessment approaches. Ontario's Scorecard links performance measurement with strategy, aimed at health system integration. The Dutch Health Care Performance Report (Zorgbalans does not explicitly link performance with strategy, and focuses on the technical quality of healthcare by measuring dimensions of quality, access, and cost against healthcare needs. A backbone 'five diamond' framework maps both frameworks and articulates the interrelations and overlap between their goals, themes, dimensions and indicators. The workshop yielded more contextual insights and further validated the comparative values of each constituency's performance assessment system. Conclusion To compare the health system performance approaches between The Netherlands and Ontario, Canada, several important conceptual and contextual issues must be addressed

  11. Consumption of Lake Ontario sport fish and the incidence of colorectal cancer in the New York State Angler Cohort Study (NYSACS). (United States)

    Callahan, Catherine L; Vena, John E; Green, Joseph; Swanson, Mya; Mu, Lina; Bonner, Matthew R


    Fish consumption is hypothesized to reduce the risk of colorectal cancer. Nonetheless, consuming sport fish from the Great Lakes increases exposure to certain persistent organic pollutants, namely polychlorinated biphenyls (PCBs) and organochlorine insecticides, which may increase the risk of cancer. Evidence that exposure to persistent organic pollutants is associated with colorectal cancer is sparse. We examined colorectal cancer incidence in the New York State Angler Cohort Study (NYSACS), a prospective cohort of 17,110 anglers and spouses age 18-40 years at enrollment. In 1991, participants completed a mailed self-administered questionnaire that ascertained the number of years that fish from Lake Ontario were consumed, as well as potential confounders. Forty-one histologically confirmed first primary incident colorectal cancers diagnosed as of December 31, 2008 were identified via the New York State Cancer Registry. Vital status was ascertained by linkage with the Social Security Administration Death File. Rate ratios (RR) and 95% confidence intervals (CI) were calculated with Poisson regression, adjusting for age, pack-years of smoking, and sex. Compared with never consumers, colorectal cancer incidence was statistically non-significantly lower among consumers of Lake Ontario sport fish (RR=0.66; 95% CI: 0.35; 1.24). Incidence of colon cancer was lower among Lake Ontario sport fish consumers (RR=0.45, 95%CI: 0.20; 1.00). We did not observe any evidence of effect measure modification by sex or age. Although consumption of Lake Ontario sport fish may have an inverse association with colorectal cancer risk, inferences are complicated by a small number of cases and a lack of information regarding potential confounders including other dietary factors. However, our results do not provide support for the hypothesis that consumption of contaminated sport fish increases the risk of colorectal cancer. Published by Elsevier Inc.

  12. Quality of fracture risk assessment in post-fracture care in Ontario, Canada


    Allin, S.; Munce, S.; Schott, A.-M.; Hawker, G.; Murphy, K.; Jaglal, S. B.


    Summary As fracture risk assessment is a basis for treatment decisions, accurate risk assessments on bone mineral density (BMD) reports are important. Over 50?% of sampled BMD reports for Ontarians with fracture histories underestimated fracture risk by a single category. Risk assessments in Ontario may not accurately inform treatment recommendations. Introduction The shifting emphasis on fracture risk assessment as a basis for treatment recommendations highlights the importance of ensuring t...

  13. What Do Teachers Need? An Exploration of Evidence-Informed Practice for Classroom Assessment in Ontario (United States)

    Cooper, Amanda; Klinger, Don A.; McAdie, Patricia


    Background: Within the realm of public education, there is a well-known "knowledge to practice gap" on current conceptions of classroom assessment. A collaborative research project undertaken by the Elementary Teachers' Federation of Ontario (ETFO) and a research team at Queen's University explored the roots of this gap from the…

  14. Chemical and biological status of headwater lakes in the Sault Ste. Marie District, Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, J.R.M.; Love, R.J.; Lipsit, J.H.; Dermott, R.


    The fish, benthos, and phytoplankton reflected to varying degrees the acidic status of their aquatic system. Although lakes in the Sault Ste. Marie district range from acidic to well buffered, the link of acidic state to atmospheric acid addition is circumstantial, as historical data is limited. Nevertheless, a significant proportion of lakes in the district are acidic, high in aluminum and lead concentrations, and poorly buffered. Biota in these lakes are to some extent protected by their life style and species tolerance against further change in acidic status. Benthos are notably harbored against changes occurring in the water column by the ability of their microhabitat to counteract changes in lake pH. On the other hand, when behavior or development of the benthos removes them from the sediment, they then are prone to effects of predators, competitors, and lake chemistry. The phytoplankton of these lakes, while responding directly to lake conditions by shifts in community, do not appear to alter dramatically in community composition. Fish, on the other hand, operate much as the benthos with the response to acid state tempered by species tolerance, life style, metabolism of contaminants, and their compensation to changes induced by acidification in other trophic levels. In natural systems, although white sucker are generally more sensitive to low pH than brook trout, difference in life style alters exposure to and uptake of contaminants and may favor existence of white sucker. In total, it seems that although benthos and phytoplankton respond to changes in their habitat, the effect upon fish is more blatant as seen through population success or metabolism of contaminants. 10 figures, 7 tables.

  15. A hydrological prediction system based on the SVS land-surface scheme: efficient calibration of GEM-Hydro for streamflow simulation over the Lake Ontario basin (United States)

    Gaborit, Étienne; Fortin, Vincent; Xu, Xiaoyong; Seglenieks, Frank; Tolson, Bryan; Fry, Lauren M.; Hunter, Tim; Anctil, François; Gronewold, Andrew D.


    This work explores the potential of the distributed GEM-Hydro runoff modeling platform, developed at Environment and Climate Change Canada (ECCC) over the last decade. More precisely, the aim is to develop a robust implementation methodology to perform reliable streamflow simulations with a distributed model over large and partly ungauged basins, in an efficient manner. The latest version of GEM-Hydro combines the SVS (Soil, Vegetation and Snow) land-surface scheme and the WATROUTE routing scheme. SVS has never been evaluated from a hydrological point of view, which is done here for all major rivers flowing into Lake Ontario. Two established hydrological models are confronted to GEM-Hydro, namely MESH and WATFLOOD, which share the same routing scheme (WATROUTE) but rely on different land-surface schemes. All models are calibrated using the same meteorological forcings, objective function, calibration algorithm, and basin delineation. GEM-Hydro is shown to be competitive with MESH and WATFLOOD: the NSE √ (Nash-Sutcliffe criterion computed on the square root of the flows) is for example equal to 0.83 for MESH and GEM-Hydro in validation on the Moira River basin, and to 0.68 for WATFLOOD. A computationally efficient strategy is proposed to calibrate SVS: a simple unit hydrograph is used for routing instead of WATROUTE. Global and local calibration strategies are compared in order to estimate runoff for ungauged portions of the Lake Ontario basin. Overall, streamflow predictions obtained using a global calibration strategy, in which a single parameter set is identified for the whole basin of Lake Ontario, show accuracy comparable to the predictions based on local calibration: the average NSE √ in validation and over seven subbasins is 0.73 and 0.61, respectively for local and global calibrations. Hence, global calibration provides spatially consistent parameter values, robust performance at gauged locations, and reduces the complexity and computation burden of the

  16. A hydrological prediction system based on the SVS land-surface scheme: efficient calibration of GEM-Hydro for streamflow simulation over the Lake Ontario basin

    Directory of Open Access Journals (Sweden)

    É. Gaborit


    Full Text Available This work explores the potential of the distributed GEM-Hydro runoff modeling platform, developed at Environment and Climate Change Canada (ECCC over the last decade. More precisely, the aim is to develop a robust implementation methodology to perform reliable streamflow simulations with a distributed model over large and partly ungauged basins, in an efficient manner. The latest version of GEM-Hydro combines the SVS (Soil, Vegetation and Snow land-surface scheme and the WATROUTE routing scheme. SVS has never been evaluated from a hydrological point of view, which is done here for all major rivers flowing into Lake Ontario. Two established hydrological models are confronted to GEM-Hydro, namely MESH and WATFLOOD, which share the same routing scheme (WATROUTE but rely on different land-surface schemes. All models are calibrated using the same meteorological forcings, objective function, calibration algorithm, and basin delineation. GEM-Hydro is shown to be competitive with MESH and WATFLOOD: the NSE  √  (Nash–Sutcliffe criterion computed on the square root of the flows is for example equal to 0.83 for MESH and GEM-Hydro in validation on the Moira River basin, and to 0.68 for WATFLOOD. A computationally efficient strategy is proposed to calibrate SVS: a simple unit hydrograph is used for routing instead of WATROUTE. Global and local calibration strategies are compared in order to estimate runoff for ungauged portions of the Lake Ontario basin. Overall, streamflow predictions obtained using a global calibration strategy, in which a single parameter set is identified for the whole basin of Lake Ontario, show accuracy comparable to the predictions based on local calibration: the average NSE  √  in validation and over seven subbasins is 0.73 and 0.61, respectively for local and global calibrations. Hence, global calibration provides spatially consistent parameter values, robust performance at gauged locations, and reduces the

  17. Feasibility Study of Shoreline Protection and Lake Level Regulation for Lake Ontario. Reconnaissance Report. Volume II. Appendices. (United States)


    principal commercial navigation facility. The only Federal project along the lake- shore of the county is a light-draft harbor at Sackets Harbor. Private...spe- cies of amphipods. Examples of these chironomids are Chironomus, spp., Procladius spp., Cryptochironomus spp. (Ellis, Haines , Makarewicz 1977...Henderson Harbor and Sackets Harbor. Several parks and recreation areas, including 15 State parks, are scattered along the New York shorelands. There are

  18. Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Martha Patricia Celis-Salgado


    Full Text Available Smelting of sulphur-rich metallic ores in Sudbury, Ontario, Canada, has caused acidification and metal contamination of thousands of lakes in the region. Recent reductions in smelter emissions have resulted in much ecological recovery, but the recovery of Daphnia species has been poor. To determine if Cu and Ni toxicity could explain differences in daphniid recovery among lakes, we compared results of 14 d static with renewal bioassays in waters from Blue Chalk Lake, an uncontaminated reference lake 200 km from Sudbury, and from five Sudbury lakes ranging in distance from the smelters and varying in metal and cation concentrations. We spiked Blue Chalk Lake water with Cu and Ni to levels resembling those of the Sudbury lakes and also tested the lake waters for toxicity. Survival of Daphnia pulex, D. pulicaria and D. mendotae decreased monotonically with increasing metal concentrations in the spiked Blue Chalk Lake treatments, falling from 90% in the controls to 0% at the two highest Cu and Ni levels, reflecting levels of Middle and Hannah lakes. In contrast, survival in waters collected from the actual Sudbury lakes did not monotonically track their total metal concentrations. Rather, survival fell to 0% in Clearwater Lake water, a lake with intermediate metal contamination (8.9 and 79.9 μg L–1 of Cu and Ni, respectively vs 70-100% in the other lakes. We performed an additional assay with Clearwater Lake waters increasing its Ca and Na concentrations, singly and in combination to levels that reflected the levels in Middle Lake. The survival of the four daphniid species increased from 0% up to 80-100% with added Ca and from 0% to 60-90% with added Na. Lipid-ovarian indices had a similar trend to survival for D. mendotae and D. pulicaria in Bioassay 1, varying with the cation concentrations in the lakes for the daphniids in Bioassay 2. The bioassays results imply that regional recovery patterns of daphniids in Sudbury lakes cannot be understood

  19. Environmental Monitoring, Water Quality - Lakes Assessments - Non Attaining (United States)

    NSGIC Education | GIS Inventory — This layer shows only non attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water...

  20. Scaled-chrysophyte assemblage changes in the sediment records of lakes recovering from marked acidification and metal contamination near Wawa, Ontario, Canada

    Directory of Open Access Journals (Sweden)

    John P. Smol


    Full Text Available A remarkable example of point-source lake acidification and metal pollution, and subsequent recovery in limnological variables, has occurred in lakes near the former iron sintering plant at Wawa (Ontario, Canada. Surface water pH levels in some of these lakes have increased from 3 to 7 following local sulphur emission reductions with closure of industrial operations. Previous paleolimnological work documented striking successional changes in diatom species assemblages within dated sediment cores that could be related to past industrial activities. To gain additional insights into the chemical and biological recovery trajectories of the Wawa lakes, we used paleolimnological techniques to track euplanktonic scaled-chrysophyte (classes Chrysophyceae and Synurophyceae species assemblage responses to historical water quality changes in five lakes. Coincident with the period of iron sintering from 1939 to 1998, striking successional changes were noted in the sedimentary profiles, with marked increases in the relative abundances of the acid- and metal-tolerant taxon Synura echinulata. The scaled chrysophyte changes pre-dated diatom responses, confirming the former’s status as reliable early warning indicators of lake acidification. Following closure of the sintering plant, species-specific chrysophyte responses to decreased emissions varied amongst the study lakes, perhaps reflecting differences in local bedrock geology and hydrological regime. Although some water chemistry variables may have recovered to near pre-industrial levels, similar to the diatom study, our data show that chrysophyte assemblages in the most recent sediments are now significantly different from pre-industrial assemblages.

  1. Michigan lakes: An assessment of water quality (United States)

    Minnerick, R.J.


    Michigan has more than 11,000 inland lakes, that provide countless recreational opportunities and are an important resource that makes tourism and recreation a $15-billion-dollar per-year industry in the State (Stynes, 2002). Knowledge of the water-quality characteristics of inland lakes is essential for the current and future management of these resources.Historically the U. S. Geological Survey (USGS) and the Michigan Department of Environmental Quality (MDEQ) jointly have monitored water quality in Michigan's lakes and rivers. During the 1990's, however, funding for surface-water-quality monitoring was reduced greatly. In 1998, the citizens of Michigan passed the Clean Michigan Initiative to clean up, protect, and enhance Michigan's environmental infrastructure. Because of expanding water-quality-data needs, the MDEQ and the USGS jointly redesigned and implemented the Lake Water-Quality Assessment (LWQA) Monitoring Program (Michigan Department of Environmental Quality, 1997).

  2. A review of (elementary school self-assessment processes: Ontario and beyond

    Directory of Open Access Journals (Sweden)

    Thomas G. Ryan


    Full Text Available This review draws attention to issues related to school self-assessment. This process has been similarly implemented in a variety of jurisdictions globally in the past decade hence their inclusion herein as an attempt to understand the school self-assessment process which has also been developed for use in local Ontario (Canadian elementary schools. This review includes an examination of the foundational components of effective schools, the purpose of school self-assessment, and the successes and challenges of school self-assessment both locally and internationally.

  3. Source-receptor relationships for speciated atmospheric mercury at the remote Experimental Lakes Area, northwestern Ontario, Canada

    Directory of Open Access Journals (Sweden)

    I. Cheng


    Full Text Available Source-receptor relationships for speciated atmospheric mercury measured at the Experimental Lakes Area (ELA, northwestern Ontario, Canada were investigated using various receptor-based approaches. The data used in this study include gaseous elemental mercury (GEM, mercury bound to fine airborne particles (<2.5 μm (PHg, reactive gaseous mercury (RGM, major inorganic ions, sulphur dioxide, nitric acid gas, ozone, and meteorological variables, all of which were measured between May 2005 and December 2006. The source origins identified were related to transport of industrial and combustion emissions (associated with elevated GEM, photochemical production of RGM (associated with elevated RGM, road-salt particles with absorption of gaseous Hg (associated with elevated PHg and RGM, crustal/soil emissions, and background pollution. Back trajectory modelling illustrated that a remote site, like ELA, is affected by distant Hg point sources in Canada and the United States. The sources identified from correlation analysis, principal components analysis and K-means cluster analysis were generally consistent. The discrepancies between the K-means and Hierarchical cluster analysis were the clusters related to transport of industrial/combustion emissions, photochemical production of RGM, and crustal/soil emissions. Although it was possible to assign the clusters to these source origins, the trajectory plots for the Hierarchical clusters were similar to some of the trajectories belonging to several K-means clusters. This likely occurred because the variables indicative of transport of industrial/combustion emissions were elevated in at least two or more of the clusters, which means this Hg source was well-represented in the data.

  4. Little Galloo Island, Lake Ontario: A review of nine years of double-crested cormorant diet and fish consumption information (United States)

    Johnson, James H.; Ross, Robert M.; McCullough, Russ D.


    The diet of double-crested cormorants (Phalacrocorax auritus) on Little Galloo Island (LGI) in the eastern basin of Lake Ontario has been quantified since 1992. Over the past nine years considerable information has been generated on cormorant feeding ecology through the examination of approximately 12,000 pellets collected on LGI, where three distinct cormorant feeding periods, pre-chick, chick, and post-chick, are delineated by differences in diet composition and daily fish consumption. Yellow perch (Perca flavescens) were the major prey during pre-chick and post-chick feeding periods. Alewife (Alosa pseudoharengus), which move inshore to spawn in mid-June, dominated (>60%) cormorant diets during the chick feeding period. Mean daily fish consumption (14.6) during the pre-chick feeding period was significantly greater than during the chick feeding (9.3) or post-chick feeding (8.0) periods. The proportion of smallmouth bass (Micropterus dolomieu) in the diet increased over the season (0.8% to 7.2%), while the size of bass consumed declined (214 mm to 143 mm). Forage fish (mainly alewife, three-spine sticklebacks [Gasterosteus aculeatus] and minnows) comprised 58% of the diet of LGI cormorants, followed by panfish (37%) (yellow perch, pumpkinseed [Lepomis gibbosus], rock bass [Ambloplites rupestris]) and gamefish (5%) (mostly smallmouth bass). On the average LGI cormorants consumed about 32.8 million fish annually, weighing about 1.4 million kilograms. Cormorants from LGI consumed more biomass of smallmouth bass and yellow perch annually than is taken by sport (bass and yellow perch) and commercial (perch) fishermen.

  5. Count trends for migratory Bald Eagles reveal differences between two populations at a spring site along the Lake Ontario shoreline

    Directory of Open Access Journals (Sweden)

    Kyle R. Wright


    Full Text Available The recovery of Bald Eagles (Haliaeetus leucophalus, after DDT and other organochlorine insecticides were banned in the United States, can be regarded as one of the most iconic success stories resulting from the Endangered Species Act. Interest remains high in the recovery and growth of the Bald Eagle population. Common to evaluating growth and recovery rates are counts at nesting sites and analyses of individuals fledged per season. But this is merely one snapshot that ignores survival rates as eagles grow to maturity. By analyzing indices from migration counts, we get a different snapshot better reflecting the survival of young birds. Different populations of Bald Eagles breed at different sites at different times of the year. Typical migration count analyses do not separate the populations. A separation of two distinct populations can be achieved at spring count sites by taking advantage of the tendency for northern summer breeding birds to migrate north in spring earlier than southern winter breeding birds who disperse north later in spring. In this paper I analyze migratory indices at a spring site along Lake Ontario. The analysis shows that eagles considered to be primarily of the northern summer breeding population showed an estimated growth rate of 5.3 ± 0.85% (SE per year with 49% of eagles tallied in adult plumage, whereas the migrants considered to be primarily of the southern breeding population had an estimated growth rate of 14.0 ± 1.79% with only 22% in adult plumage. Together these results argue that the populations of southern breeding Bald Eagles are growing at a substantially higher rate than northern breeding eagles. These findings suggest that aggregate population indices for a species at migration counting sites can sometimes obscure important differences among separate populations at any given site and that separating counts by time period can be a useful way to check for differences among sub-populations.

  6. Environmental Assessment: Submerged Aquatic Plant Management of Banks Lake, Banks Lake NWR, Lakeland, Georgia (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is an analysis of five alternatives developed to address themanagement of the submerged aquatic plants of Banks Lake on Banks Lake...

  7. 1997-1998 lake water quality assessment for Upper Des Lacs Lake, North Dakota (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of the data collected on Upper Des Lacs Lake as part of the State's Lake Water Quality Assessment Project. The Project is designed to characterize...

  8. Assessing glacial lake outburst flood risk (United States)

    Kougkoulos, Ioannis; Cook, Simon; Jomelli, Vincent; Clarke, Leon; Symeonakis, Elias


    Glaciers across the world are thinning and receding in response to atmospheric warming. Glaciers tend to erode subglacial basins and deposit eroded materials around their margins as lateral-frontal terminal moraines. Recession into these basins and behind impounding moraines causes meltwater to pond as proglacial and supraglacial lakes. Consequently, there has been a general trend of increasing number and size of these lakes associated with glacier melting in many mountainous regions around the globe, in the last 30 years. Glacial lake outburst floods (GLOFs) then may occur where the glacial lake dam (ice, rock, moraine, or combination thereof) is breached, or overtopped, and thousands of people have lost their lives to such events in the last few decades, especially in the Andes and in the Himalaya. Given the ongoing and arguably increasing risk posed to downstream communities, and infrastructure, there has been a proliferation of GLOF studies, with many seeking to estimate GLOF hazard or risk in specific regions, or to identify 'potentially dangerous glacial lakes'. Given the increased scientific interest in GLOFs, it is timely to evaluate critically the ways in which GLOF risk has been assessed previously, and whether there are improvements that can be made to the ways in which risk assessment is achieved. We argue that, whilst existing GLOF hazard and risk assessments have been extremely valuable they often suffer from a number of key shortcomings that can be addressed by using different techniques as multi-criteria decision analysis and hydraulic modelling borrowed from disciplines like engineering, remote sensing and operations research.

  9. Quality of fracture risk assessment in post-fracture care in Ontario, Canada. (United States)

    Allin, S; Munce, S; Schott, A-M; Hawker, G; Murphy, K; Jaglal, S B


    As fracture risk assessment is a basis for treatment decisions, accurate risk assessments on bone mineral density (BMD) reports are important. Over 50 % of sampled BMD reports for Ontarians with fracture histories underestimated fracture risk by a single category. Risk assessments in Ontario may not accurately inform treatment recommendations. The shifting emphasis on fracture risk assessment as a basis for treatment recommendations highlights the importance of ensuring that accurate fracture risk assessments are present on reading specialists' BMD reports. This study seeks to determine the accuracy of fracture risk assessments on a sample of BMD reports from 2008 for individuals with a history of fracture and produced by a broad cross section of Ontario's imaging laboratories. Forty-eight BMD reports for individuals with documented history of fragility fracture were collected as part of a cluster randomized trial. To compute fracture risk, risk factors, and BMD T-scores from reports were abstracted using a standardized template and compared to the assessments on the reports. Cohen's kappa was used to score agreement between the research team and the reading specialists. The weighted kappa was 0.21, indicating agreement to be at the margin of "poor to fair." More than 50 % of the time, reported fracture risks did not reflect fracture history and were therefore underestimated by a single category. Over 30 % of the reports containing a "low" fracture risk assessment were assessed as "moderate" fracture risk by the research team, given fracture history. Over 20 % of the reports with a "moderate" fracture risk were assessed as "high" by the research team, given fracture history. This study highlights the high prevalence of fracture risk assessments that are underestimated. This has implications in terms of fracture risk categorization that can negatively affect subsequent follow-up care and treatment recommendations.

  10. Lake Michigan Offshore Wind Feasibility Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Boezaart, Arnold [GVSU; Edmonson, James [GVSU; Standridge, Charles [GVSU; Pervez, Nahid [GVSU; Desai, Neel [University of Michigan; Williams, Bruce [University of Delaware; Clark, Aaron [GVSU; Zeitler, David [GVSU; Kendall, Scott [GVSU; Biddanda, Bopi [GVSU; Steinman, Alan [GVSU; Klatt, Brian [Michigan State University; Gehring, J. L. [Michigan State University; Walter, K. [Michigan State University; Nordman, Erik E. [GVSU


    The purpose of this project was to conduct the first comprehensive offshore wind assessment over Lake Michigan and to advance the body of knowledge needed to support future commercial wind energy development on the Great Lakes. The project involved evaluation and selection of emerging wind measurement technology and the permitting, installation and operation of the first mid-lake wind assessment meteorological (MET) facilities in Michigan’s Great Lakes. In addition, the project provided the first opportunity to deploy and field test floating LIDAR and Laser Wind Sensor (LWS) technology, and important research related equipment key to the sitting and permitting of future offshore wind energy development in accordance with public participation guidelines established by the Michigan Great Lakes Wind Council (GLOW). The project created opportunities for public dialogue and community education about offshore wind resource management and continued the dialogue to foster Great Lake wind resource utilization consistent with the focus of the GLOW Council. The technology proved to be effective, affordable, mobile, and the methods of data measurement accurate. The public benefited from a substantial increase in knowledge of the wind resources over Lake Michigan and gained insights about the potential environmental impacts of offshore wind turbine placements in the future. The unique first ever hub height wind resource assessment using LWS technology over water and development of related research data along with the permitting, sitting, and deployment of the WindSentinel MET buoy has captured public attention and has helped to increase awareness of the potential of future offshore wind energy development on the Great Lakes. Specifically, this project supported the acquisition and operation of a WindSentinel (WS) MET wind assessment buoy, and associated research for 549 days over multiple years at three locations on Lake Michigan. Four research objectives were defined for the

  11. Conflict Management in Participatory Approaches to Water Management: A Case Study of Lake Ontario and the St. Lawrence River Regulation

    Directory of Open Access Journals (Sweden)

    Alison Furber


    Full Text Available The International Joint Commission (IJC has been involved in a 14-year effort to formulate a new water regulation plan for the Lake Ontario St. Lawrence River (“LOSLR” area that balances the interests of a diverse group of stakeholders including shipping and navigation, hydropower, environment, recreational boating, municipal and domestic water supply, First Nations, and shoreline property owners. It has embraced the principles of collaborative and participatory management and, applying a Shared Visioning Planning (SVP approach, has worked closely with stakeholders throughout all stages of this process; however, conflicts between competing stakeholders have delayed and complicated this effort. The overarching aim of this paper is to consider the extent to which the SVP approach employed by the IJC was effective in managing conflict in the LOSLR context. Audio recordings and transcriptions of public and technical hearings held by the IJC in 2013 have been systematically analysed using stakeholder mapping and content analysis methods, to gain insight into the stakeholder universe interacting with the IJC on Plan 2014.  The principal conclusions of this paper are that (a the Shared Vision Planning approach employed by the IJC had some significant successes in terms of conflict management—particularly notable is the success that has been achieved with regards to integration of First Nation concerns; (b there is a distinct group of shoreline property owners, based in New York State, who remain opposed to Plan 2014—the IJC’s public outreach and participation efforts have not been successful in reconciling their position with that of other stakeholders due to the fact that this stakeholder group perceive that they can only lose out from any regulation change and are therefore unlikely to be motivated to engage productively in any planning dialogue; and (c a solution would require that the problem be reframed so that this stakeholder can see

  12. Assessing the adaptive capacity of the Ontario wine industry for climate change adaptation

    Directory of Open Access Journals (Sweden)

    Pickering K


    Full Text Available Kerrie Pickering,1 Ryan Plummer,1,2 Tony Shaw,3,4 Gary Pickering1,4,5 1Environmental Sustainability Research Centre, Brock University, St Catharines, ON, Canada; 2Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden; 3Department of Geography, 4Cool Climate Oenology and Viticulture Institute, 5Department of Psychology, Brock University, St Catharines, ON, Canada Background: Wine regions throughout the world are experiencing climate change characterized by the gradual alterations in growing seasons, temperature, precipitation, and the occurrences of extreme weather events that have significant consequences for quality wine production. Adapting to these new challenges depends largely on the present and future adaptive capacity of the grape growers, winemakers, and supporting institutions in order to minimize the impacts of climate change on grape yield and wine quality. Accordingly, the objective of this study was to develop a conceptual framework for assessing the adaptive capacity of a grape or wine region and apply it in the context of the Ontario wine industry. The framework consists of a three tiered structure, comprising eight operational and strategic determinants (financial, institutional, technological, political, knowledge, perception, social capital, and diversity. A comprehensive questionnaire was created from this framework consisting of 26 statements to which participants indicated their level of agreement. A total of 42 Ontario wine industry members completed the questionnaire via an on line survey. Results: The determinants related to perception, diversity, and knowledge have the highest degree of capacity, while political and technological determinants show the least. Overall, stakeholders are aware of both negative and positive impacts climate change could have on wine production. Results are discussed to explore opportunities to enhance adaptive capacity in the grape/wine community. Many stakeholders have already

  13. Establishing eutrophication assessment standards for four lake regions, China. (United States)

    Huo, Shouliang; Ma, Chunzi; Xi, Beidou; Su, Jing; Zan, Fengyu; Ji, Danfeng; He, Zhuoshi


    The trophic status assessment of lakes in different lake regions may provide important and fundamental information for lake trophic state classification and eutrophication control. In this study, a region-specific lake eutrophication assessment standard was established through a frequency distribution method based on chlorophyll-a concentration. The assessment standards under the oligotrophic state for lakes in the Eastern plain, Yungui Plateau, Northeast Plain and Mountain Mongolia-Xinjiang regions are total phosphorus of 0.068, 0.005, 0.011, 0.005 mg/L; total nitrogen of 1.00, 0.16, 0.37, 0.60 mg/L; Secchi depth of 0.60, 8.00, 1.55, 3.00 m; and COD(Mn) of 2.24, 1.00, 5.11, 4.00 mg/L, respectively. Moreover, a region-specific comprehensive trophic level index was developed to provide an understandable assessment method for the public. The results indicated that the frequency distribution analysis based on chlorophyll-a combined with trophic level index provided a useful metric for the assessment of the lake trophic status. In addition, the difference of eutrophication assessment standards in different lake regions was analyzed, which suggested that the sensitivities of algae to nutrients and the assessment standard of trophic status possessed significant regional differences for the four lake ecoregions. Lake eutrophication assessment standards would contribute to maximizing the effectiveness of future management strategies, to control and minimize lake eutrophication problems.

  14. The effects of acid and particulate precipitation on phytoplankton and lake chemistry in the Sudbury region of Ontario, Canada (United States)

    P. M. Stokes; T. C. Hutchinson


    The Sudbury basin, Ontario is the source of more than 60% of the free world's nickel and is also a major producer of copper, iron, cobalt and other metals. The sulfur dioxide and particulate discharge from the Sudbury smelters have been described and discussed in a number of publications and information will also be presented at the present conference.

  15. Zika Virus in Ontario: Evaluating a Rapid Risk Assessment Tool for Emerging Infectious Disease Threats. (United States)

    Van Meer, Ryan; Hohenadel, Karin; Fitzgerald-Husek, Alanna; Warshawsky, Bryna; Sider, Doug; Schwartz, Brian; Nelder, Mark P

    To determine the Ontario-specific risk of local and travel-related Zika virus transmission in the context of a public health emergency of international concern, Public Health Ontario (PHO) completed a rapid risk assessment (RRA) on January 29, 2016, using a newly developed RRA guidance tool. The RRA concluded that risk of local mosquito-borne transmission was low, with a high risk of imported cases through travel. The RRA was updated 3 times based on predetermined triggers. An independent evaluation assessed both the application of the RRA guidance tool (process evaluation) and the usefulness of the RRA (outcome evaluation). We conducted face-to-face, semi-structured interviews with 7 individuals who participated in the creation or review of the Zika virus RRA and 4 end-users at PHO and the Ministry of Health and Long-Term Care. An inductive thematic analysis of responses was undertaken, whereby themes were directly informed by the data. The process evaluation determined that most steps outlined in the RRA guidance tool were adhered to, including forming a cross-functional writing team, clarifying the scope and describing context, completing the RRA summary report, and updating the RRA based on predefined triggers. The outcome evaluation found that end-users judged the Zika virus RRA as evidence-informed, useful, consistent, and timely. The evaluation established that the locally tailored guidance tool, adapted from national and international approaches to RRAs, facilitated a systematic, evidence-informed, and timely formal RRA process at PHO for the Zika virus RRA, which met the needs of end-users. Based on the evaluation, PHO will modify future RRAs by incorporating some flexibility into the literature review process to support timeliness of the RRA, explicitly describing the limitations of studies used to inform the RRA, and refining risk algorithms to better suit emerging infectious disease threats. It is anticipated that these refinements will improve upon the

  16. Sediment sequences and palynology of outer South Bay, Manitoulin Island, Ontario: Connections to Lake Huron paleohydrologic phases and upstream Lake Agassiz events (United States)

    Lewis, C. F. M.; Anderson, T. W.


    South Bay on the southern coast of Manitoulin Island is a fjord-like embayment connected to Lake Huron by a natural narrow gap in the bay's outer sill 6.5-14 m above the lake. A seismic profile, pollen, plant macrofossil, grain size analyses, and other sediment properties of two piston cores from a shallow outer basin of the bay document a 9 m-thick sediment section comprising rhythmically laminated clay under silty clay containing zones with small molluscan shells and marsh detritus. A sandy pebbly layer under soft silty clay mud overlies these sediments. This stratigraphy represents inundation by deep glacial Lake Algonquin followed by the shallowing Post Algonquin series of lakes, and exposure in the early Holocene by 5 Lake Stanley lowstands in the Lake Huron basin separated by 4 Lake Mattawa highstands. Overflow from South Bay in the first lowstand is thought to have eroded the outer sill gap. Marsh environments are inferred to have formed in the bay during subsequent lowstands. The Lake Mattawa highstands are attributed to outburst floods mainly from glacial Lake Agassiz. Palynological evidence of increased spruce occurrence, an apparent regional climate reversal, during the dry pine period is attributed to cold northwest winds from the Lake Superior basin and a lake effect from the Mattawa highstands in the Lake Huron basin. Lake waters transgressed South Bay following the pine period to form the Nipissing shore on Manitoulin Island. Transfer of Lake Huron basin drainage to southern outlets and continued glacioisostatic uplift of the region led to the present configuration of South Bay and Lake Huron.

  17. Assessing the effects of multiple environmental stressors on zooplankton assemblages in Boreal Shield lakes since pre-industrial times

    Directory of Open Access Journals (Sweden)

    John P. SMOL


    Full Text Available Zooplankton communities in Boreal Shield lakes of south-central Ontario, Canada, have become increasingly exposed to the effects of multiple anthropogenic stressors, such as declines in calcium (Ca and total phosphorus (TP concentrations, shifts in predation regimes, and climate warming. The paleolimnological approach provides an effective means of examining cladoceran zooplankton communities prior to the onset of these major environmental stressors and assessing how the increasing impacts of these stressors have affected zooplankton community composition. We examined the chitinized remains of cladocerans from recent and pre-industrial (pre- ~1850s sediments in 42 oligotrophic lakes from south-central Ontario and compared these assemblages using ANOSIM and SIMPER. Differences in cladoceran assemblages since pre-industrial times were related to five environmental variables that significantly influence cladoceran community composition in surface sediments. These included measured physical (depth, chemical [Ca, pH, sulphate, dissolved organic carbon (DOC], and biological (fish community biomass limnological variables. Two changes were recorded in the cladoceran species assemblages of the study lakes. The first was a significant increase in the ratio of pelagic species compared to littoral species over time in most lakes which we cannot attribute to any measured environmental variable with certainty but it likely represents a multiple stressor effect. The second was changes in relative abundances of daphniid cladocerans in several lakes since pre-industrial times, which we attribute to the interactive effects of several environmental stressors, including: differences in Ca availability within our lakes, resulting in decreased abundances of daphniids over time in lakes with lower Ca levels; long-term increases in DOC concentrations, which may provide refuge for daphniids from visual predators; and long-term declines in TP concentrations which may

  18. Benthic fauna of 41 acid sensitive headwater lakes in north central Ontario. [Chironomidae salinarius; Chironomidae anthracinus; Tanytarsini

    Energy Technology Data Exchange (ETDEWEB)

    Dermott, R.; Kelso, J.R.M.; Douglas, A.


    The benthic fauna of 41 nonhumic, soft water lakes situated north of lakes Superior and Huron were sampled during 1980. The pH range of the lakes sampled was 4.6 to 7.7. The benthic infauna displayed regional differences in abundance and composition, with large variation with each district. Total abundance, biomass, and number of taxa were not correlated with lake pH or alkalinity. The Chironomidae displayed a slight change in percent composition of the major species with lower pH. The Tanytarsini and Chironomus Salinarius group decreased, while C. anthracinus group increased in relative abundance in those lakes with lower pH. Other factors appear to control the distribution of the various invertebrate orders, with depth and sediment nature being important variables.

  19. Great Lakes Bathymetry (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

  20. Reduced metals concentrations of water, sediment and hyalella azteca from lakes in the vicinity of the sudbury metal smelters, Ontario, Canada. (United States)

    Shuhaimi-Othman, M; Pascoe, D; Borgmann, U; Norwood, W P


    Hyalella azteca (Crustacea: Amphipoda), water and sediments from 12 circum-neutral lakes between Sudbury and North Bay in Ontario, Canada were sampled in August 1998 and analyzed for 10 metals including Cu, Zn, Cd, Ni, Pb, Co, Mo, V, Ba and Ti. Statistical analyses showed that concentrations of the metals in H. azteca, water and sediment differed significantly (ANOVA, Pazteca and Mo in water). There was a trend of declining metal concentration, especially for Cu, Ni and Co (in water, Hyalella and sediment), with distance from the smelters indicating the reduced impact of atmospheric pollution. Metal concentrations of lakes (water) in the Sudbury area were found to be lower compared to data from the 1970s and 1980s indicating an improvement in water quality. Metal concentrations in field-collected amphipods compared favorably with those measured in the laboratory in animals exposed to deep-water sediments, provided metal concentrations were not extremely low (e.g., Pb) and that water chemistry differences (e.g., pH) were taken into account for some metals (especially Cd). In general bioaccumulation of metals in H. azteca was predicted better from surface water than from sediment total metal.

  1. Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River (United States)

    Groocock, G.H.; Getchell, R.G.; Wooster, G.A.; Britt, K.L.; Batts, W.N.; Winton, J.R.; Casey, R.N.; Casey, J.W.; Bowser, P.R.


    In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d post-inoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations. ?? Inter-Research 2007.

  2. Assessment of Potentially Dangerous Glacial Lakes in Chinese Himalayas (United States)

    Xiaojun, Yao; Shiyin, Liu; Xin, Wang


    Glacial lake outburst floods (GLOFs) are catastrophic discharges of water resulting primarily from melting glaciers. In the face of global warming, most Himalayan glaciers have been retreating at a rate that ranges from a few meters to several tens of meters per year, resulting in an increase in the number and size and size of glacial lakes and a concomitant increase in the threat of GLOFs. In the past 50 years, 16 GLOF events which were reported in Tibet had caused the loss of human lives as well as severe damage to local infrastructure. Based on the combination of temperature and precipitation of these 14 failed moraine-dammed lakes, the climatic background could be classified into 4 types, that is, warm-wet, warm-arid, cold-wet and near common weather condition. Under different climatic background types, the outburst mechanisms can be further divided into 5 types and 21 modes based on the analysis of 31 failed moraine-dammed lakes documented all over the world. As to a potentially dangerous moraine-dammed lake, all possible breach modes under each climatic background are firstly described and its qualitative possibilities are given by experts, then the decision-making trees are formed and the breach probability of the potentially dangerous moraine-dammed lake can be calculate. The breaching probabilities of the 143 potentially dangerous moraine-dammed lakes were calculated one by one using the decision-making trees model in Chinese Himalayas. The calculating results show that there are 44 lakes with very high breaching probability, 47 lakes with high breaching probability, 24 lakes with median breaching probability, 24 lakes with low breaching probability, 4 lakes with very low breaching probability. The 91 lakes with very high and high breaching probability rate should be requested in the next steps of detailed assessment and should be took into account in local infrastructure construction, such as road, hydropower station and residential plan, etc. Key words

  3. Health impact assessment of Ontario's green energy and green economy act. The roles of environmental informatics in sustainability

    Energy Technology Data Exchange (ETDEWEB)

    Rattle, Robert


    Renewable energy received a boost in Ontario, Canada with the Green Energy and Green Economy Act (GEGEA), ushering in a new Feed-in-Tariff (FIT) program modelled on programs from Germany, Spain, Denmark and other jurisdictions. Information about lessons learned elsewhere has clearly benefited the Ontario experience. Part of the Ontario program included streamlining the impact assessment process to facilitate the swift development of provincial renewable energy capacities. In this context, the GEGEA has been remarkably successful, generating renewable energy sector capacities, resources, projects and their spin-off benefits in Ontario, along with more sustainable electricity system. Environmentalists along with industry continue to laud the benefits of renewable energy and the GEGEA, and with good reason. Renewable energy generation in Ontario has grown from to 2 per cent in 2012 and is expected to reach 10 per cent in 2013. (orig.)

  4. Development and application of an operational Probabilistic Risk Assessment (PRA) at Ontario Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Kaasalainen, S.; Mok, J.; Donnelly, K.; Dinnie, K. [Nuclear Safety Solutions Ltd., Toronto, Ontario (Canada); Ganguli, S.; Moisin, M. [Ontario Power Generation, Pickering, Ontario (Canada)


    Ontario Power Generation Inc. has embraced the use of Probabilistic Risk Assessment (PRA) in operational decision-making. Common examples include decisions related to continued operation while in an abnormal plant configuration based on incremental risk increase, and the use of risk monitors (i.e., Equipment Out-of-Service (EOOS)) for outage planning and managing risk during on-line maintenance. Unlike the baseline PRA where average risk is calculated, these operational decisions/tools are best made using a real-time, or instantaneous analysis reflecting actual plant configuration. The process of taking the baseline, time-averaged PRA, to an instantaneous model is part of broader process of 'operationalizing' the plant PRA. Additional items in the process include activities related to the development of the risk monitors themselves, and the development and establishment of procedures and governance related to the use of the PRA and risk monitors in applications. This paper looks into the processes and factors requiring consideration when 'operationalizing' a nuclear power plant PRA. As well, the paper includes a case study describing the use of an operational PRA to support the decision-making process at Pickering NGS B. (author)

  5. Heavy metal pollution assessment in the sediments of lake Chad ...

    African Journals Online (AJOL)

    Sediments were collected from Dumba and KwataYobe of Lake Chad, Nigerian Sector.The aim was to assess the pollution statusof the sediments of the lake. The concentration of heavy metals, Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), lead (Pb), Z (Zn) and Arsenic (As) were ...

  6. Microbial safety assessment of recreation water at Lake Nabugabo ...

    African Journals Online (AJOL)


    Key words: Lake Nabugabo, microbial safety assessment, recreation water, water quality. INTRODUCTION. Contamination of ... facilities) at the shores, contamination potential of the lake has increased. Compared to other ..... Department of Water Affairs and Forestry (DWA) (1996). South African. Wter Quality Guidelines ...

  7. Modelling and water yield assessment of Lake Sibhayi | Smithers ...

    African Journals Online (AJOL)

    This study has been undertaken to establish the probable causes of the almost 4 m drop in the level of Lake Sibhayi between 2001 and 2014, to assess the impact of abstractions for domestic water consumption and by commercial plantations on lake levels, and to determine what sustainable yield can be abstracted from ...

  8. Fall diets of alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario during 1994-2005 with an emphasis on occurrence of Mysis relicta (United States)

    Walsh, M.G.; O'Gorman, R.; Strang, T.; Edwards, W.H.; Rudstam, L. G.


    In Lake Ontario, factors including the collapse of the burrowing amphipod, Diporeia spp., changes in the distribution and composition of the prey fish community, and occurrence of exotic cladocerans Bythotrephes longimanus and Cercopagis pengoi have led to changes in predation pressure on the remaining native profundal macroinvertebrate, Mysis relicta. We conducted a diet study on three important prey fishes, alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), and slimy sculpin (Cottus cognatus) in 2002-2005 at depths 75-130 m along the south shore of Lake Ontario to evaluate the current role of Mysis in the diets of these species relative to earlier studies and previously unpublished data from 1994-1995. Mysis have remained an important prey item for alewife, rainbow smelt, and slimy sculpin in the profundal zone of southern Lake Ontario through 2005, indicating that the population has been able to sustain itself following the collapse of Diporeia. Although the occurrence of Diporeia in prey fish diets was minimal in 2003-2005, Bythotrephes longimanus and Cercopagis pengoi played an important role in the diet of alewife and a minor role in the diet of rainbow smelt, and may actually serve to mitigate predation pressure on Mysis, particularly in years when they are very abundant. Conversely, without Diporeia, the benthic slimy sculpin was primarily reliant on Mysis as a prey item and would be most vulnerable to a decline in the Mysis population. Copyright ?? 2008 AEHMS.

  9. Age, size and regeneration of old growth white pine at Dividing Lake Nature Reserve, Algonquin Park, Ontario (United States)

    Richard P. Guyette; Daniel C. Dey


    The age, mode of regeneration and diameter growth of white pine were determined in an old growth stand near Dividing Lake, Algonquin Provincial Park. The white pine ranged in age from 267 to 486 years. There was no significant relationship between white pine age and diameter (DBH). The distribution of tree ages indicated that the white pine component in this mixed...

  10. Building Teachers' Assessment Capacity for Supporting English Language Learners through the Implementation of the Step Language Assessment in Ontario K-12 Schools (United States)

    Van Viegen Stille, Saskia; Jang, Eunice; Wagner, Maryam


    The Ontario Ministry of Education recently implemented the Steps to English Proficiency (STEP) language assessment framework to build educator capacity for addressing the needs of English language learners (ELLs) in K-12 schools. The STEP framework is a set of descriptors-based language proficiency scales that specify observable linguistic…

  11. Clinical Telemedicine Utilization in Ontario over the Ontario Telemedicine Network


    O'Gorman, Laurel D.; Hogenbirk, John C; Warry, Wayne


    Abstract Introduction: Northern Ontario is a region in Canada with approximately 775,000 people in communities scattered across 803,000?km2. The Ontario Telemedicine Network (OTN) facilitates access to medical care in areas that are often underserved. We assessed how OTN utilization differed throughout the province. Materials and Methods: We used OTN medical service utilization data collected through the Ontario Health Insurance Plan and provided by the Ministry of Health and Long Term Care. ...

  12. Environmental Assessment : Crescent Lake National Wildlife Refuge Hunting Plan (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment (EA) is for the implementation of the Crescent Lake National Wildlife Refuge Hunting Plan that serves as a step down management plan to...

  13. Occurrence of chlorinated paraffins in beluga whales (Delphinapterus leucas) from the St. Lawrence River and rainbow trout (Oncorhynchus mykiss) and carp (Cyprinus carpio) from Lake Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Bennie, D. T.; Sullivan, C. A.; Maguire, R. J. [Envirronment Canada, National Water Research Institute, Burlington, ON (Canada)


    Samples of 25 dead beluga whales from the St. Lawrence River estuary, as well as samples of 10 rainbow trout and three carps caught in western Lake Ontario were analyzed for total short and medium chain chlorinated paraffins using gas chromatography-low resolution negative chemical ionization spectroscopy. Both short and medium-chain chlorinated paraffins were quantitatively identified in all samples using two commercial preparations. Beluga results were found to be higher than concentrations reported for marine mammals in Europe, but comparable to total PCB and total DDT results for the same population of beluga whales. Results for freshwater species are comparable to those reported for fish sampled from other industrially impacted waterways in North America, but elevated compared to marine species from European studies. Comparisons of the results with gas chromatography-negative ion mass spectroscopy analysis from another study indicated that the two analytical techniques are not congruent. The differences may be accounted for by different effects of interfering organochlorine substances on the analysis of chlorinated paraffins. 22 refs., 5 tabs., 1 fig.

  14. Henry's law constants for hexachlorobenzene, p,p'-DDE and components of technical chlordane and estimates of gas exchange for Lake Ontario. (United States)

    Jantunen, Liisa M; Bidleman, Terry F


    The Henry's law constants (HLC) for trans- and cis-chlordane (TC, CC), trans-nonachlor (TN), hexachlorobenzene (HCB) and p,p'-DDE were determined by the gas-stripping method over a temperature range of 5-35 degrees C. The HLC variation versus temperature (K) was described by logH=m/T+b. Parameters of this equation were (with standard deviations) TC: m=-1524+/-158, b=6.58+/-0.54; CC: m=-1786+/-209, b=7.42+/-0.71; TN m=-2068+/-284, b=8.44+/-0.97; HCB: m=-3013+/-174, b=11.60+/-0.59 and p,p'-DDE: m=-2043+/-240, b=8.37+/-0.82. The HLCs (Pa m3 mol(-1)) at 25 degrees C (298.15 K) were: TC=29; CC=27; TN=32; p,p'-DDE=33 and HCB=35. These HLCs values were used to calculate fugacity ratios from paired air and water data from Lake Ontario, July 1998. The resulting fugacity ratios predict that volatilization was occurring for all compounds during that month.

  15. Influence of nearshore structure on growth and diets of yellow perch (Perca flavescens) and white perch (Morone americana) in Mexico Bay, Lake Ontario (United States)

    Danehy, Robert J.; Ringler, Neil H.; Gannon, John E.


    The growth diets of 969 yellow perch (Perca flavescens) and white perch (Morone americana) caught at 3.3 and 7.0 m depths were compared between two cobble/rubble shoals and two featureless sand sites in Mexico Bay, eastern Lake Ontario during 1981. The growth rate of both species was significantly greater for individuals captured over the cobble/rubble shoals. Females of both species were faster growing than the males, although only significantly so in the white perch. The seasonal diet and breadth of diet (H′) of yellow perch and white perch were not substantially different with respect to substrate type. Diet overlap between substrate types was also equivalent for each species. Benthic invertebrates, primarilyGammarus spp., were the major prey of both species at all sites. Alewife eggs were the most important item for the white perch in mid-summer, and alewife juveniles were important to both species in the fall. Differences in growth patterns between cobble/rubble shoals and sand sites illustrate a subtle effect of habitat on these species.

  16. Comparing health system performance assessment and management approaches in the Netherlands and Ontario, Canada

    NARCIS (Netherlands)

    A.R. Tawfik-Shukor (Ali); N.S. Klazinga (Niek); O.A. Arah (Onyebuchi)


    textabstractBackground: Given the proliferation and the growing complexity of performance measurement initiatives in many health systems, the Netherlands and Ontario, Canada expressed interests in cross-national comparisons in an effort to promote knowledge transfer and best practise. To support

  17. Comparing health system performance assessment and management approaches in the Netherlands and Ontario, Canada

    NARCIS (Netherlands)

    A.R. Tawfik-Shukor (Ali); N.S. Klazinga (Niek); O.A. Arah (Onyebuchi)


    textabstractBackground. Given the proliferation and the growing complexity of performance measurement initiatives in many health systems, the Netherlands and Ontario, Canada expressed interests in cross-national comparisons in an effort to promote knowledge transfer and best practise. To support

  18. Climatological assessment of spatiotemporal trends in observational monthly snowfall totals and extremes over the Canadian Great Lakes Basin (United States)

    Baijnath, Janine; Duguay, Claude; Sushama, Laxmi; Huziy, Oleksandr


    The Laurentian Great Lakes Basin (GLB) is susceptible to snowfall events that derive from extratropical cyclones and heavy lake effect snowfall (HLES). The former is generated by quasigeostropic forcing from positive temperature or vorticity advection associated with low-pressure centres. HLES is produced by planetary boundary layer (PBL) convection that is initiated as a result of cold and dry continental air mass advecting over relatively warm lakes and generating turbulent moisture and heat fluxes into the PBL. HLES events can have disastrous impacts on local communities such as the November 2014 Buffalo storm that caused 13 fatalities. Albeit the many HLES studies, most are focused on specific case study events with a discernible under examination of climatological HLES trend analyses for the Canadian GLB. The research objectives are to first determine the historical, climatological trends in monthly snowfall totals and to examine potential surface and atmospheric variables driving the resultant changes in HLES. The second aims to analyze the historical extremes in snowfall by assessing the intensity, frequency, and duration of snowfall within the domain of interest. Spatiotemporal snowfall and precipitation trends are computed for the 1982 to 2015 period using Daymet (Version 3) monthly gridded observational datasets from the Oak Ridge National Laboratory. The North American Regional Reanalysis (NARR), NOAA Optimum Interpolation Sea Surface Temperature (OISST), and the Canadian Ice Service (CIS) datasets are also used for evaluating trends in HLES driving variables such as air temperature, lake surface temperature (LST), ice cover concentration, omega, and vertical temperature gradient (VTGlst-850). Climatological trends in monthly snowfall totals show a significant decrease along the Ontario snowbelt of Lake Superior, Lake Huron and Georgian Bay at the 90 percent confidence level. These results are attributed to significant warming in LST, significant

  19. Glacial lakes in the Indian Himalayas--from an area-wide glacial lake inventory to on-site and modeling based risk assessment of critical glacial lakes. (United States)

    Worni, Raphael; Huggel, Christian; Stoffel, Markus


    Glacial lake hazards and glacial lake distributions are investigated in many glaciated regions of the world, but comparably little attention has been given to these topics in the Indian Himalayas. In this study we present a first area-wide glacial lake inventory, including a qualitative classification at 251 glacial lakes >0.01 km(2). Lakes were detected in the five states spanning the Indian Himalayas, and lake distribution pattern and lake characteristics were found to differ significantly between regions. Three glacial lakes, from different geographic and climatic regions within the Indian Himalayas were then selected for a detailed risk assessment. Lake outburst probability, potential outburst magnitudes and associated damage were evaluated on the basis of high-resolution satellite imagery, field assessments and through the use of a dynamic model. The glacial lakes analyzed in the states of Jammu and Kashmir and Himachal Pradesh were found to present moderate risks to downstream villages, whereas the lake in Sikkim severely threatens downstream locations. At the study site in Sikkim, a dam breach could trigger drainage of ca. 16×10(6)m(3) water and generate maximum lake discharge of nearly 7000 m(3) s(-). The identification of critical glacial lakes in the Indian Himalayas and the detailed risk assessments at three specific sites allow prioritizing further investigations and help in the definition of risk reduction actions. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Limnological Assessment of West Point Lake, Georgia (United States)


    exchange at the air-water interface and photosynthesis by phytoplankton and periphyton. Subsequent downstream displacement of this water at the...nepheloid layers and their influence on the manganese cycling and toxicology in Oscillatoria (Cyanobacteria) in lakes," Ph.D. diss., Clemson University

  1. Lake Holloman Recreational Area Development Environmental Assessment (United States)


    1-4 1.4 Summary of Key Environmental Requirements ......................................................1-5 1.4.1 National...and Need for Development of Holloman Lake Recreational Area 1.4 Summary of Key Environmental Requirements 1.4.1 National Environmental Policy Act...Sylvilagus audubonii), kangaroo rats ( Dipodomys spp.), White sands woodrat (Neotomamicropus leaucophaea), house mouse (Mus musculus), long-tailed

  2. Assessment of lake hydromorphological status within the French territory (United States)

    Gay, Aurore; Argillier, Christine; Reynaud, Nathalie; Nicolas, Delphine; Baudoin, Jean-Marc


    In France, in accordance with the expectations of the European Water Framework Directive, the biological and physico-chemical status of lakes have been assessed thanks to the use of different indicators and threshold values (Argillier et al., 2013; Roubeix et al., 2016). However, the hydromorphological conditions have not been included in the final evaluation of the lakes ecological status yet, due to i) a lack of indicators to evaluate these conditions, ii) a lack of knowledge on the combined impact of hydromorphological changes on the biota, and iii) the difficulties in defining reference conditions for the hydromorphology of lakes. Recently, the LAKe HYdromorphological Conditions tool (LAKHYC tool, Gay et al., in prep) has been developed to overcome this lack and assess the hydromorphological conditions of lakes in Europe. The tool is successfully applied on the 201 French lakes for which accurate data are available, and which represents 42% of the total number of lakes in France with an area greater than 50ha. The first results indicate that the obtained LAKHYC values cover the entire range of possible values (between 0 and 1). The values are then grouped into 5 classes according to quintile thresholds to highlight lakes presenting a very bad/very high hydromorphological status. No sign of particular geographical distribution patterns is found. This first application of the LAKHYC tool represents an important step in the final evaluation of the ecological status of French lakes considering the biological, the physico-chemical and the hydromorphological compartments altogether. It will certainly help stakeholders to define priority lakes for financial support to implement conservation or restoration practices. As perspectives to this work, the forthcoming detailed level fluctuations data will ensure a finer and more robust estimation of the lakes hydromorphological quality. Moreover, further investigations on the link between hydromorphological degradation and

  3. Regional assessment of lake water clarity using satellite remote sensing

    Directory of Open Access Journals (Sweden)

    David L. SKOLE


    Full Text Available Lake water clarity as measured by Secchi disk transparency (SDT is a cost-effective measure of water quality. However, in regions where there are thousands of lakes, sampling even a small proportion of those lakes for SDT year after year is cost prohibitive. Remote sensing has the potential to be a powerful tool for assessing lake clarity over large spatial scales. The overall objective of our study was to examine whether Landsat-7 ETM+ could be used to measure water clarity across a large range of lakes. Our specific objectives were to: 1 develop a regression model to estimate SDT from Landsat data calibrated using 93 lakes in Michigan, U.S.A., and to 2 examine how the distribution of SDT across the 93 calibration lakes influenced the model. Our calibration dataset included a large number of lakes with a wide range of SDT values that captured the summer statewide distribution of SDT values in Michigan. Our regression model had a much lower r2 value than previously published studies conducted on smaller datasets. To examine the importance of the distribution of calibration data, we simulated a calibration dataset with a different SDT distribution by sub-sampling the original dataset to match the distribution of previous studies. The sub-sampled dataset had a much higher percentage of lakes with shallow water clarity, and the resulting regression model had a much higher r2 value than our original model. Our study shows that the use of Landsat to measure water clarity is sensitive to the distribution of water clarity used in the calibration set.

  4. Development of indicators for assessment of Lake Malawi Basin in an Integrated Lake Basin Management (ILBM framework

    Directory of Open Access Journals (Sweden)

    Clara Limbitso Chidammodzi


    Full Text Available This paper sought to understand the current state of the management environment of Lake Malawi Basin, deduce a lake vision and develop indicators for assessing Integrated Lake Basin Management (ILBM in the lake basin. The premise of the study was that targeted indicators are necessary to effectively monitor the lake basin and manage it sustainably. The study focused on the Malawian side of the lake. Interviews, field observations and review of existing lake management and indicator development approaches around the world were the methods employed. It was found that Malawi lacks focus on lakes in its strategies and the existing management of the lake is on a sector-to-sector basis with little coordination. Furthermore, the capacity of lake-related sector institutions is hampered by inadequate resources and unstable flow of funds. It was concluded that the current management of the lake basin is unsustainable and there is need to comprehensively monitor the lake basin as well as formulate and implement management plans and strategies that are based on the knowledge obtained from targeted monitoring. A set of governance indicators was developed taking into account the characteristics of the lake, the values that it offers and the threats that it is facing.

  5. U-Pb age and genetic significance of heterogeneous zircon populations in rocks from the Favourable Lake area, Northwestern Ontario (United States)

    Corfu, F.; Ayres, L. D.


    The study evaluates the relationships between measured U-Pb ages and zircon characteristics of five morphologically, texturally, and isotopically complex zircon populations and compares the zircon development stages to the orogenic evolution of the Favourable Lake area. Two distinct zircon types from a hornblendite xenolith in a granitoid batholith of the Sachigo subprovince of the Superior Province yield U-Pb ages of 2729.0±6.8 Ma and 2714.8{-6.4/+7.4}Ma, which date specific metamorphic phases coinciding with major plutonic pulses in the batholith. Zircons from a metamorphosed felsic dike, crosscutting the hornblendite, consist of an old zircon component with a minimum age of 2788 Ma possibly reflecting igneous crystallization ≧ 2950 Ma ago, and a younger component with an inferred age of 2725±15 Ma, probably reflecting metamorphism during batholith emplacement. In the Berens River subprovince to the south, granodiorite forms both a late tectonic phase in a large batholith and a post-tectonic pluton intruded into the batholith, yet zircons from these granodiorites have identical ages of 2697.3±1.7 Ma and 2696.2±1.2 Ma, respectively. The late tectonic granodiorite also contains inherited zircons with a minimum age of 2767 Ma which are indirect evidence for the presence of old sialic crust in this subprovince. Zircons from a sheared monzonite near the boundary fault between the two subprovinces yield an upper intercept age of 2769{-26/+63}Ma, which we interpret as the intrusion age of the monzonite. This rock is older than most dated units in the surrounding batholiths and suggests that the boundary is a long-lived Archean structure. A lower intercept age of about 1750 Ma for zircons of the hornblendite is the result of chemical alteration of the zircons. This, and a similar lower intercept age shown by the sheared monzonite zircons, are thought to reflect increased fluid activity and possibly shearing during the Early Proterozoic Hudsonian orogeny which

  6. Occurrence and Habitat Use of Wintering Bald Eagles on Eastern Lake Ontario and the St. Lawrence River (1955-1993) (United States)

    US Fish and Wildlife Service, Department of the Interior — Occurrence and habitat use data for bald eagles (Haliaeetus leucocephalus), was compiled for use in planning a study to assess the potential effects of environmental...

  7. An assessment of short rotation coppice (SRC) woody biomass to heat greenhouses in southern Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D.; Fraleigh, S.; McKenney, D.; Yemshanov, D. [Natural Resources Canada, Sault Ste. Marie, ON (Canada). Canadian Forest Service Great Lakes Forestry Centre


    This presentation identified the best options/scenarios for short rotation coppice (SRT) bioenergy systems as an alternative to fossil fuel supply. Research priorities associated with heating greenhouses with SRC woody biomass were also evaluated along with the economic potential of short-rotation forestry systems to supply biomass for energy production. The presentation outlined the key steps in the production of willow biomass crops and provided an overview of a fast-growing hybrid poplar and willow bio-energy plantation located in Claremont, Ontario. Photographs of established treatments were presented. The presentation also discussed the Canadian Forest Service's SRC greenhouse heating model (GHM) which consisted of a spreadsheet-based cost-benefit analysis tool used to evaluate the feasibility of purpose-grown woody biomass for small scale bioenergy systems to replace existing fossil fuel systems. The model considered greenhouse dimensions, thermal resistance factors of materials, construction factors, system factors, local weather conditions, and desired indoor temperature to determine annual heating requirements. A series of charts and graphs depicted model variables and inputs for southern Ontario; results for the internal rate of return, net present value, and payback period; and results of break even fuel prices versus appliance efficiency and growth rate assumptions; sensitivity analysis; and regional analysis. The presentation also discussed the Canadian Forest Service bioeconomic model and geographical distribution of break-even willow prices. It was concluded that future work should consider un-priced potential environmental benefits and carbon offsets. tabs., figs.

  8. Transcultural adaptation, validation and assessment of the psychometric properties of the spanish version of the Western Ontario Shoulder Instability Index questionnaire. (United States)

    Yuguero, M; Huguet, J; Griffin, S; Sirvent, E; Marcano, F; Balaguer, M; Torner, P

    The aim of the present study is to present a transcultural adaptation and validation of the Western Ontario Shoulder Instability Index questionnaire into Spanish (Spain), and to assess its psychometric properties. The transcultural adaptation was conducted according to sequential forward and backward translation approach. A pilot study was subsequently performed to ensure acceptable psychometric properties. The Western Ontario Shoulder Instability Index questionnaire was administered to 79 patients twice within a period of 2 months, and patients were stratified into 3 groups (cohorts). CONCLUSIONS: The Spanish version of the Western Ontario Shoulder Instability Index questionnaire is a valid, reliable tool, and highly sensitive to change to assess patients with shoulder instability. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Lake Surface Water Temperature of European Lakes retrieved from AVHRR Data - Time Series and Quality Assessment (United States)

    Wunderle, S.; Lieberherr, G.; Riffler, M.


    Data analysis of the recent years showed an increase of lake surface water temperature for many lakes around the world. But due to sparse in-situ measurements, which are often not well documented, only satellite data can provide the needed information of the last decades. The importance of lakes for climate research was also highlighted by the Global Climate Observing System (GCOS) defining lakes as Essential Climate Variables (ECVs). Within the frame of a research project funded by the Swiss National Science Foundation a procedure was developed to retrieve lake surface water temperature with high accuracy based on our archived AVHRR data at the University of Bern, Switzerland. The data archive starts in 1985 and is continuously filled with NOAA-/MetOp-AVHRR data received by our antenna resulting in a time series of more than 30 years (WMO definition of a climate period). The data set covering Europe is also used by other teams for climate related studies resulting in improved pre-processing to guarantee precise calibration and geocoding. The first part of our presentation will be dedicated to the quality of the LSWT retrieval comparing various in-situ measurements from lakes in Switzerland with varying sizes (150km2 - 9km2). The quality of the used split-window approach is sensitive to the derived split-window coefficients. The influence of water vapor, view angle, temporal and spatial validity and day vs. night data will be shown. In addition, some information will be presented about the influence of topography and climatic regions (e.g. Scandinavia vs. Greece) on the quality of the LSWT product. Based on these findings compiling time series for different lakes in Europe will be the focus of the second part of our presentation with details of the applied quality assessment to avoid erroneous signals. Hence, some information is given about hierarchical quality checks which are needed to guarantee a dataset without artefacts. Finally, some results of time series

  10. Diatom-inferred depth models in 8 Canadian boreal lakes: inferred changes in the benthic:planktonic depth boundary and implications for assessment of past droughts (United States)

    Laird, Kathleen R.; Kingsbury, Melanie V.; Lewis, C. F. Michael; Cumming, Brian F.


    Assessment of past drought in boreal regions, a region predicted to be strongly affected by climate warming, can provide insights into future availability of water. However, limited instrumental data and paleoclimatic data are available for this assessment. To address this lack of data in the boreal region of northwest Ontario, a regional study of lakes in the Winnipeg River Drainage Basin was initiated. Diatom-inferred (D-I) depth models were developed based on surface samples collected along a depth gradient within 8 small boreal lakes. Weighted-averaging and modern analog approaches provided robust within-lake depth models for each of the study lakes, with bootstrapped r2 values ranging from 0.90 to 0.98, and root-mean-squared-errors of prediction (RMSEP) between 1.1 and 2.5 m. Large differences in the estimated depth optima for three representative, but common diatom species across our 8 study lakes suggested that within-lake calibration datasets are more appropriate for inferring past drought based in depth models than a regional multi-lake calibration dataset, and that light and related variables are controlling factors governing the maximum depth of benthic taxa. A down-core application of the D-I depth models on a near-shore core from Meekin Lake, retrieved near the present-day ecotone between the benthic and planktonic diatom assemblages indicated highly similar trends in inferred depth ( r = 0.96). The models have significant correlations with other metrics of changes in depth including diatom species richness ( r = 0.74-0.78) and evenness ( r = 0.76-0.8), thereby allowing a check on the strength and direction of the depth inferences down-core. Near-shore cores located near the benthic:planktonic transition is a sensitive region that can provide estimates of past droughts in lakes where such inferences have been difficult to estimate.

  11. An environmental assessment of water replenishment to a floodplain lake. (United States)

    Lóczy, Dénes; Dezső, József; Czigány, Szabolcs; Prokos, Hedvig; Tóth, Gabriella


    There are numerous wetland rehabilitation projects worldwide, but their efficiency is seldom assessed comprehensively. Oxbow lakes are wetlands of particular sensitivity. Within a large-scale floodplain rehabilitation project in Hungary, the Old Drava Programme, water replenishment was first carried out for the Cún-Szaporca oxbow lakes, a key area in the project. To assess its sustainability, the entire hydrological system has been monitored. From the data of hydrological monitoring (infiltration, soil moisture, groundwater/lakewater interaction) it is claimed that water replenishment involves significant losses through seepage (4.1 and 1.46 mm d(-1)) and evaporation (3.01 and 1.44 mm d(-1)) in the studied pre-intervention and replenishment periods, resp. Infiltration alone is insufficient to replenish groundwater and raise oxbow lake levels. In the critical summer half-year evaporation is intensive in the neighbouring agricultural fields. Groundwater table dynamics are controlled by hyporheic and groundwater flow. Major impact on the water balance of the oxbow lakes is exerted by the regime of the Drava River. A deepened lakebed is recommended to ensure more effective water retention in the oxbow lake. From the local study conclusions are drawn for the feasibility of rehabilitation at floodplain scale and in areas with similar hydromorphological conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Assessment of heavy metals in Lake Uluabat, Turkey | Elmaci ...

    African Journals Online (AJOL)

    The accumulation of heavy metals (Cu, Ni, Zn, Cd, Pb, Cr, B, As) was measured in water, plankton and sediment samples taken from different areas of Lake Uluabat during January 2003 to February 2004. The sequential extraction used in this study is useful to assess the potential mobility of heavy metals in the sediment ...

  13. Microbial safety assessment of recreation water at Lake Nabugabo ...

    African Journals Online (AJOL)


    This study assessed the microbial safety of Lake Nabugabo beaches for recreation. Faecal microbial indicators and physico-chemical characteristics of beach recreational water were determined. Water sampling was done between 10.00 and 11.30 h and 1700 and 18.00 h. Data was analysed using student t- tests, ANOVA ...

  14. Ecological Assessment of Lake Hora, Ethiopia, Using Benthic and ...

    African Journals Online (AJOL)

    The purpose of this study was ecological assessment of Lake Hora using benthic and weed-bed fauna. Samples of benthic and weed-bed were collected monthly from September 2009 to March 2010 at 3 sampling stations (A, B, C), with a standard Ekman grab. Station A is in front of Ras Hotel, Station B is place of Irecha ...

  15. Analyzing Sustainable Energy Opportunities for a Small Scale Off-Grid Facility: A Case Study at Experimental Lakes Area (ELA), Ontario (United States)

    Duggirala, Bhanu

    This thesis explored the opportunities to reduce energy demand and renewable energy feasibility at an off-grid science "community" called the Experimental Lakes Area (ELA) in Ontario. Being off-grid, ELA is completely dependent on diesel and propane fuel supply for all its electrical and heating needs, which makes ELA vulnerable to fluctuating fuel prices. As a result ELA emits a large amount of greenhouse gases (GHG) for its size. Energy efficiency and renewable energy technologies can reduce energy consumption and consequently energy cost, as well as GHG. Energy efficiency was very important to ELA due to the elevated fuel costs at this remote location. Minor upgrades to lighting, equipment and building envelope were able to reduce energy costs and reduce load. Efficient energy saving measures were recommended that save on operating and maintenance costs, namely, changing to LED lights, replacing old equipment like refrigerators and downsizing of ice makers. This resulted in a 4.8% load reduction and subsequently reduced the initial capital cost for biomass by 27,000, by 49,500 for wind power and by 136,500 for solar power. Many alternative energies show promise as potential energy sources to reduce the diesel and propane consumption at ELA including wind energy, solar heating and biomass. A biomass based CHP system using the existing diesel generators as back-up has the shortest pay back period of the technologies modeled. The biomass based CHP system has a pay back period of 4.1 years at 0.80 per liter of diesel, as diesel price approaches $2.00 per liter the pay back period reduces to 0.9 years, 50% the generation cost compared to present generation costs. Biomass has been successfully tried and tested in many off-grid communities particularly in a small-scale off-grid setting in North America and internationally. Also, the site specific solar and wind data show that ELA has potential to harvest renewable resources and produce heat and power at competitive

  16. Integration of Bayesian analysis for eutrophication prediction and assessment in a landscape lake. (United States)

    Yang, Likun; Zhao, Xinhua; Peng, Sen; Zhou, Guangyu


    Eutrophication models have been widely used to assess water quality in landscape lakes. Because flow rate in landscape lakes is relatively low and similar to that of natural lakes, eutrophication is more dominant in landscape lakes. To assess the risk of eutrophication in landscape lakes, a set of dynamic equations was developed to simulate lake water quality for total nitrogen (TN), total phosphorous (TP), dissolve oxygen (DO) and chlorophyll a (Chl a). Firstly, the Bayesian calibration results were described. Moreover, the ability of the model to reproduce adequately the observed mean patterns and major cause-effect relationships for water quality conditions in landscape lakes were presented. Two loading scenarios were used. A Monte Carlo algorithm was applied to calculate the predicated water quality distributions, which were used in the established hierarchical assessment system for lake water quality risk. The important factors affecting the lake water quality risk were defined using linear regression analysis. The results indicated that the variations in the landscape lake receiving recharge water quality caused considerable landscape lake water quality risk in the surrounding area. Moreover, the Chl a concentration in lake water was significantly affected by TP and TN concentrations; the lake TP concentration was the limiting factor for growth of plankton in lake water. The lake water TN concentration provided the basic nutritional requirements. Lastly, lower TN and TP concentrations in the receiving recharge water caused increased lake water quality risk.

  17. Water Quality Assessment of the Central Himalayan Lake, Nainital

    Directory of Open Access Journals (Sweden)

    Madhuben Sharma


    Full Text Available The Nainital Lake, situated in the central Himalayas of India, is an important water body and a major tourist spot. This study aims to identify factors or processes that determine the water quality of the lake. For this purpose, water samples from two different points were collected—highly polluted (Mallital and least polluted (Tallital—to represent the actual level of pollution in the lake in four different seasons (January, April, July, and October. The collected samples were analyzed for different physical and chemical parameters. In order to assess the state of the lake’s water quality, the samples were compared with the standard water quality values. Turbidity, electrical conductivity, total alkalinity, and heavy metal (lead, iron, and copper concentration were found to be above the desirable limit of the prescribed national and international standards in all four seasons at both Mallital and Tallital. Reasons affecting the water quality were found to be natural (thermal stratification and lead-bearing rocks and anthropogenic (domestic sewage, runoff, and illegal construction activities in the vicinity of lake. Various lake restoration alternatives/interventions have been suggested that can lead to an improvement in the lake’s water quality, such as afforestation, phytoremediation, and sediment basin.

  18. Assessment of suitable habitat for Phragmites australis (common reed) in the Great Lakes coastal zone (United States)

    Carlson Mazur, Martha L.; Kowalski, Kurt P.; Galbraith, David


    In the Laurentian Great Lakes, the invasive form of Phragmites australis (common reed) poses a threat to highly productive coastal wetlands and shorelines by forming impenetrable stands that outcompete native plants. Large, dominant stands can derail efforts to restore wetland ecosystems degraded by other stressors. To be proactive, landscape-level management of Phragmites requires information on the current spatial distribution of the species and a characterization of areas suitable for future colonization. Using a recent basin-scale map of this invasive plant’s distribution in the U.S. coastal zone of the Great Lakes, environmental data (e.g., soils, nutrients, disturbance, climate, topography), and climate predictions, we performed analyses of current and predicted suitable coastal habitat using boosted regression trees, a type of species distribution modeling. We also investigated differential influences of environmental variables in the upper lakes (Lakes Superior, Michigan, and Huron) and lower lakes (Lakes St. Clair, Erie, and Ontario). Basin-wide results showed that the coastal areas most vulnerable to Phragmites expansion were in close proximity to developed lands and had minimal topographic relief, poorly drained soils, and dense road networks. Elevated nutrients and proximity to agriculture also influenced the distribution of Phragmites. Climate predictions indicated an increase in suitable habitat in coastal Lakes Huron and Michigan in particular. The results of this study, combined with a publicly available online decision support tool, will enable resource managers and restoration practitioners to target and prioritize Phragmites control efforts in the Great Lakes coastal zone.

  19. Assessment of spatial rainfall variability in Lake Victoria Basin (United States)

    Kizza, M.; Westerberg, I.; Rodhe, A.; Ntale, H. K.


    A gridded monthly rainfall dataset having a spatial resolution of 2 km and covering the period 1960-2004 was derived for the Lake Victoria basin. Such a dataset is useful for hydrological modelling aimed at resource utilisation and for estimation of catchment inflow to Lake Victoria. The lake and its basin support more than 30 million people and also contribute substantially to the River Nile flow. The major challenge in analysing the lake water balance is the estimation of the rainfall over the lake which is complicated by the varying quality and spatial coverage of rain-gauge data in the basin. In this study we addressed these problems by using satellite-derived precipitation data from two products and rain-gauge data for 362 stations around the basin to derive a monthly precipitation dataset for the entire basin, including the lake. First, the rain-gauge data were quality controlled; resulting in a rejection of 13% of the stations while 12% needed corrective actions. These results emphasise the importance of a systematic quality control of rain-guage data in this region. Thereafter we filled short gaps in the daily data series which resulted in 9,429 additional months of data. Two interpolation methods were then assessed for spatial interpolation and the universal kriging method performed slightly better than the inverse distance weighting method. The rainfall patterns in the interpolated dataset were shown to be consistent with the spatial and temporal patterns expected at the large scale as a result of the climate variability in the basin. The key problem of how to account for the enhancement of rainfall over the lake surface because of the lake-land thermal contrasts was addressed by estimating a relationship between rain-gauge and satellite data. Two satellite rainfall products, TRMM 3B43 and PERSIANN were compared to the interpolated monthly rain-gauge data for the land part of the basin. The bias in the TRMM 3B43 rainfall estimates was higher than the bias

  20. Assessing the Impact of Pilot School Snack Programs on Milk and Alternatives Intake in 2 Remote First Nation Communities in Northern Ontario, Canada (United States)

    Gates, Michelle; Hanning, Rhona M.; Gates, Allison; McCarthy, Daniel D.; Tsuji, Leonard J. S.


    Background: Canadian Aboriginal youth have poorer diet quality and higher rates of overweight and obesity than the general population. This research aimed to assess the impact of simple food provision programs on the intakes of milk and alternatives among youth in Kashechewan and Attawapiskat First Nations (FNs), Ontario, Canada. Methods: A pilot…

  1. A Pan-Arctic Assessment of High-Latitude Lake Change ~25 Years Apart (United States)

    Sheng, Y.; Smith, L. C.; Li, J.; Lyons, E. A.; Wang, J.


    The Arctic and Sub-Arctic regions are the home to the world's largest quantity of terrestrial lakes. These lakes play a preeminent role in the global water cycle and balance, are sensitive to global warming, and are vital for human and animal water supply. However, they are poorly observed, and a uniform lake inventory is unavailable at the pan-Arctic scale. Though there have been studies of Arctic lake dynamics at local scales, the general picture of Arctic lake change stays unclear. A systematic regional-scale assessment of Arctic lake change in the past ~30 years is crucial for us to address "How have Arctic lakes responded to global warming?" The presentation reports a systematic effort of high-latitude (45N and north) lake inventory using recently available high-resolution satellite imagery. Since Arctic lakes are abundant in small-size classes and their seasonality varies from region to region, pan-Arctic lake mapping requires the use of thousands of cloud-free Landsat images acquired in lake-stable seasons. Nearly eight million lakes have been mapped in various landscapes of the pan-Arctic using automated lake identification algorithms with high replicability. Lake-abundant regions are selected using a systematic sampling strategy to detect decadal lake change using the mid-1970s and circa-2000 Landsat imagery. Spatial patterns of the observed lake dynamics are analyzed at regional scales and the relationship between lake abundance and size distribution is investigated.

  2. Review of Reports on Lake Erie-Lake Ontario Waterway, New York. Appendix E. Impact Assessment and Environment Plan. (United States)


    Crops The dominant land-use type along most of the prt)psed route ()t the canal is agricultural. A- food chains and nutrient t y les are de- pendent or as a means of flood-plain protection. E-74 .. ... .... . . .. . . . . .. ... .. .I.1 YouNGS TOWN -iR* N LEGENTO BCAMBRIA Devoped Zone

  3. Indians culture in the tourism of Ontario

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    Besermenji Snežana


    Full Text Available The first association to potential tourists, when they mention Ontario or Canada, is endless and untouched natural area. Numerous forest areas and beautiful lakes, wild animals moving freely in these expanses of the famous Niagara Falls are important part of Ontario tourism offer. Regarding cultural assets of Ontario and of the entire Canada, it may not have old city quarters as Europe, but it certainly has a long history. This history includes Indians whose customs and culture are very interesting for tourists.

  4. Clinical Telemedicine Utilization in Ontario over the Ontario Telemedicine Network. (United States)

    O'Gorman, Laurel D; Hogenbirk, John C; Warry, Wayne


    Northern Ontario is a region in Canada with approximately 775,000 people in communities scattered across 803,000 km(2). The Ontario Telemedicine Network (OTN) facilitates access to medical care in areas that are often underserved. We assessed how OTN utilization differed throughout the province. We used OTN medical service utilization data collected through the Ontario Health Insurance Plan and provided by the Ministry of Health and Long Term Care. Using census subdivisions grouped by Northern and Southern Ontario as well as urban and rural areas, we calculated utilization rates per fiscal year and total from 2008/2009 to 2013/2014. We also used billing codes to calculate utilization by therapeutic area of care. There were 652,337 OTN patient visits in Ontario from 2008/2009 to 2013/2014. Median annual utilization rates per 1,000 people were higher in northern areas (rural, 52.0; urban, 32.1) than in southern areas (rural, 6.1; urban, 3.1). The majority of usage in Ontario was in mental health and addictions (61.8%). Utilization in other areas of care such as surgery, oncology, and internal medicine was highest in the rural north, whereas primary care use was highest in the urban south. Utilization was higher and therapeutic areas of care were more diverse in rural Northern Ontario than in other parts of the province. Utilization was also higher in urban Northern Ontario than in Southern Ontario. This suggests that telemedicine is being used to improve access to medical care services, especially in sparsely populated regions of the province.

  5. Assessment of water quality in Ahor Lake - Ghana | Amfo-Otu ...

    African Journals Online (AJOL)

    Assessment of water quality in Ahor Lake - Ghana. R Amfo-Otu, ED Wiafe, BB Kocke. Abstract. In the bid to boost the tourism industry, West Akyem Municipal Assembly identified Lake Ahor, a manmade lake as a potential tourism site in the municipality. However, the quality of the water is not known hence the assessment of ...

  6. Western Lake Erie Restoration Assessment Degree Flowlines (United States)

    U.S. Geological Survey, Department of the Interior — This represents the flowline network in Western Lale Erie Restoration Assessment (WLERA). It is attributed with the number of disconnections between the reach and...

  7. Western Lake Erie Restoration Assessment Composite Model (United States)

    U.S. Geological Survey, Department of the Interior — Well-established conservation planning principles and techniques framed by geodesign were used to assess the restorability of areas that historically supported...

  8. A preliminary biological assessment of Long Lake National Wildlife Refuge Complex, North Dakota (United States)

    US Fish and Wildlife Service, Department of the Interior — This report represents an initial biological assessment of wetland conditions on Long Lake National Wildlife Refuge (NWR), Slade NWR, and Florence Lake NWR that was...

  9. Update to hazard assessment of selenium contamination at Benton Lake National Wildlife Refuge (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a study done to assess selenium levels on Benton Lake NWR. Water was sampled for dissolved selenium in Lake Creek at the point where it enters...

  10. Community capacity to acquire, assess, adapt, and apply research evidence: a survey of Ontario's HIV/AIDS sector

    Directory of Open Access Journals (Sweden)

    Rourke Sean B


    Full Text Available Abstract Background Community-based organizations (CBOs are important stakeholders in health systems and are increasingly called upon to use research evidence to inform their advocacy, program planning, and service delivery. To better support CBOs to find and use research evidence, we sought to assess the capacity of CBOs in the HIV/AIDS sector to acquire, assess, adapt, and apply research evidence in their work. Methods We invited executive directors of HIV/AIDS CBOs in Ontario, Canada (n = 51 to complete the Canadian Health Services Research Foundation's "Is Research Working for You?" survey. Findings Based on responses from 25 organizations that collectively provide services to approximately 32,000 clients per year with 290 full-time equivalent staff, we found organizational capacity to acquire, assess, adapt, and apply research evidence to be low. CBO strengths include supporting a culture that rewards flexibility and quality improvement, exchanging information within their organization, and ensuring that their decision-making processes have a place for research. However, CBO Executive Directors indicated that they lacked the skills, time, resources, incentives, and links with experts to acquire research, assess its quality and reliability, and summarize it in a user-friendly way. Conclusion Given the limited capacity to find and use research evidence, we recommend a capacity-building strategy for HIV/AIDS CBOs that focuses on providing the tools, resources, and skills needed to more consistently acquire, assess, adapt, and apply research evidence. Such a strategy may be appropriate in other sectors and jurisdictions as well given that CBO Executive Directors in the HIV/AIDS sector in Ontario report low capacity despite being in the enviable position of having stable government infrastructure in place to support them, benefiting from long-standing investment in capacity building, and being part of an active provincial network. CBOs in other

  11. Monitoring and assessment of anthropogenic activities in mountain lakes: a case of the Fifth Triglav Lake in the Julian Alps. (United States)

    Ravnikar, Tina; Bohanec, Marko; Muri, Gregor


    The Fifth Triglav Lake is a remote mountain lake in the Julian Alps. The area of the Julian Alps where the lake is situated is protected by law and lies within the Triglav National Park. Mountain lakes in Slovenia were considered for a long time as pristine, unpolluted lakes, but analyses in the last decade revealed considerable human impact even in such remote places. Eutrophication or excessive accumulation of nutrients is the main problem of most lakes in the temperate climatic zone, also in Slovenia. Since the introduction of fish in 1991, the lake is going through a series of changes for which we do not know exactly where they lead, so the monitoring and assessment of anthropogenic activities are of great importance. For this purpose, a qualitative multiattribute decision model was developed with DEX method to assess ecological effects on the lake. The extent of the ecological effects on the lake is assessed using four main parameters: the trophic state, lake characteristics, environmental parameters, and anthropogenic stressors. Dependence of environmental impact on various external factors beyond human control, such as temperature, precipitation, retention time, and factors on which we have influence, such as the amount of wastewater and the presence of fish in the lake, were also evaluated. The following data were measured: chlorophyll a, nutrients, TP, oxygen, C/N ratio, nutrients in sediment, temperature, precipitation, retention time, and volume. We made assumptions about fish and wastewater, which we could not measure. The main contributions of this work are the designed model and the obtained findings for the Fifth Triglav Lake that can help not only scientists in understanding the complexity of lake-watershed systems and interactions among system components but also local authorities to manage and monitor the lake aquatic environment in an effective and efficient way. The model is flexible and can be also used for other lakes, assuming that the used

  12. A comparative analysis of current microbial water quality risk assessment and management practices in British Columbia and Ontario, Canada. (United States)

    Dunn, Gemma; Harris, Leila; Cook, Christina; Prystajecky, Natalie


    Bacteria, protozoa and viruses are ubiquitous in aquatic environments and may pose threats to water quality for both human and ecosystem health. Microbial risk assessment and management in the water sector is a focus of governmental regulation and scientific inquiry; however, stark gaps remain in their application and interpretation. This paper evaluates how water managers practice microbial risk assessment and management in two Canadian provinces (BC and Ontario). We assess three types of entities engaged in water management along the source-to-tap spectrum (watershed agencies, water utilities, and public health authorities). We analyze and compare the approaches used by these agencies to assess and manage microbial risk (including scope, frequency, and tools). We evaluate key similarities and differences, and situate them with respect to international best practices derived from literatures related to microbial risk assessment and management. We find considerable variability in microbial risk assessment frameworks and management tools in that approaches 1) vary between provinces; 2) vary within provinces and between similar types of agencies; 3) have limited focus on microbial risk assessment for ecosystem health and 4) diverge considerably from the literature on best practices. We find that risk assessments that are formalized, routine and applied system-wide (i.e. from source-to-tap) are limited. We identify key limitations of current testing methodologies and looking forward consider the outcomes of this research within the context of new developments in microbial water quality monitoring such as tests derived from genomics and metagenomics based research. © 2013 Elsevier B.V. All rights reserved.

  13. GIS-based pollution hazard mapping and assessment framework of shallow lakes: southeastern Pampean lakes (Argentina) as a case study. (United States)

    Romanelli, A; Esquius, K S; Massone, H E; Escalante, A H


    The assessment of water vulnerability and pollution hazard traditionally places particular emphasis on the study on groundwaters more than on surface waters. Consequently, a GIS-based Lake Pollution Hazard Index (LPHI) was proposed for assessing and mapping the potential pollution hazard for shallow lakes due to the interaction between the Potential Pollutant Load and the Lake Vulnerability. It includes easily measurable and commonly used parameters: land cover, terrain slope and direction, and soil media. Three shallow lake ecosystems of the southeastern Pampa Plain (Argentina) were chosen to test the usefulness and applicability of this suggested index. Moreover, anthropogenic and natural medium influence on biophysical parameters in these three ecosystems was examined. The evaluation of the LPHI map shows for La Brava and Los Padres lakes the highest pollution hazard (≈30 % with high to very high category) while Nahuel Rucá Lake seems to be the less hazardous water body (just 9.33 % with high LPHI). The increase in LPHI value is attributed to a different loading of pollutants governed by land cover category and/or the exposure to high slopes and influence of slope direction. Dissolved oxygen and biochemical oxygen demand values indicate a moderately polluted and eutrophized condition of shallow lake waters, mainly related to moderate agricultural activities and/or cattle production. Obtained information by means of LPHI calculation result useful to perform a local diagnosis of the potential pollution hazard to a freshwater ecosystem in order to implement basic guidelines to improve lake sustainability.

  14. Environmental Assessment of a proposed reconstruction of the Lower Red Rock Lake dam : Red Rock Lakes National Wildlife Area (United States)

    US Fish and Wildlife Service, Department of the Interior — Environmental Assessment (EA) for the renovation and attendant modifications to a water control dike on Red Rock Lakes National Wildlife Refuge, Montana. Completion...

  15. Lake Michigan Wind Assessment Analysis, 2012 and 2013

    Directory of Open Access Journals (Sweden)

    Charles R Standridge


    Full Text Available A study was conducted to address the wind energy potential over Lake Michigan to support a commercial wind farm.  Lake Michigan is an inland sea in the upper mid-western United States.  A laser wind sensor mounted on a floating platform was located at the mid-lake plateau in 2012 and about 10.5 kilometers from the eastern shoreline near Muskegon Michigan in 2013.  Range gate heights for the laser wind sensor were centered at 75, 90, 105, 125, 150, and 175 meters.  Wind speed and direction were measured once each second and aggregated into 10 minute averages.  The two sample t-test and the paired-t method were used to perform the analysis.  Average wind speed stopped increasing between 105 m and 150 m depending on location.  Thus, the collected data is inconsistent with the idea that average wind speed increases with height. This result implies that measuring wind speed at wind turbine hub height is essential as opposed to using the wind energy power law to project the wind speed from lower heights.  Average speed at the mid-lake plateau is no more that 10% greater than at the location near Muskegon.  Thus, it may be possible to harvest much of the available wind energy at a lower height and closer to the shoreline than previously thought.  At both locations, the predominate wind direction is from the south-southwest.  The ability of the laser wind sensor to measure wind speed appears to be affected by a lack of particulate matter at greater heights.   Keywords: wind assessment, Lake Michigan, LIDAR wind sensor, statistical analysis. Article History: Received June 15th 2016; Received in revised form January 16th 2017; Accepted February 2nd 2017 Available online How to Cite This Article: Standridge, C., Zeitler, D., Clark, A., Spoelma, T., Nordman, E., Boezaart, T.A., Edmonson, J.,  Howe, G., Meadows, G., Cotel, A. and Marsik, F. (2017 Lake Michigan Wind Assessment Analysis, 2012 and 2013. Int. Journal of Renewable Energy Development

  16. Lakes sensitivity to climatic stress – a sociological assessment

    Directory of Open Access Journals (Sweden)

    Lackowska Marta


    Full Text Available One of the conditions for effective water resources management in protected areas is local decision makers’ knowledge about potential threats caused by climate changes. Our study, conducted in the UNESCO Biosphere Reserve of Tuchola Forest in Poland, analyses the perception of threats by local stakeholders. Their assessments of the sensitivity of four lakes to the extreme weather events are compared with hydrological studies. The survey shows that the lakes’ varying responses to extreme weather conditions is rarely noticed by ordinary observers. Their perception is usually far from the hydrological facts, which indicates a lack of relevant information or a failure in making it widely accessible and understandable. Moreover, it is rather the human impact, not climate change, which is seen as the biggest threat to the lakes. Insufficient environmental knowledge may hinder the effective protection and management of natural resources, due to bad decisions and lack of the local communities’ support for adaptation and mitigation policies.

  17. Value distribution assessment of geothermal development in Lake County, CA

    Energy Technology Data Exchange (ETDEWEB)

    Churchman, C.W.; Nelson, H.G.; Eacret, K.


    A value distribution assessment is defined as the determination of the distribution of benefits and costs of a proposed or actual development, with the intent of comparing such a development with alternative plans. Included are not only the social and economic effects, but also people's perceptions of their roles and how they are affected by the proposed or actual development. Discussion is presented under the following section headings: on morality and ethics; the vanishing community; case study of pre-development planning--Lake County; methodology for research; Lake County geothermal energy resource; decision making; Planning Commission hearing; communication examples; benefit tracing; response to issues raised by the report of the State Geothermal Task Force; and, conclusions and recommendations. (JGB)

  18. Oncology Nurses' Attitudes Toward the Edmonton Symptom Assessment System: Results From a Large Cancer Care Ontario Study. (United States)

    Green, Esther; Yuen, Dora; Chasen, Martin; Amernic, Heidi; Shabestari, Omid; Brundage, Michael; Krzyzanowska, Monika K; Klinger, Christopher; Ismail, Zahra; Pereira, José


    To examine oncology nurses' attitudes toward and reported use of the Edmonton Symptom Assessment System (ESAS) and to determine whether the length of work experience and presence of oncology certification are associated with their attitudes and reported usage.
. Exploratory, mixed-methods study employing a questionnaire approach.
. 14 regional cancer centers (RCCs) in Ontario, Canada.
. Oncology nurses who took part in a larger province-wide study that surveyed 960 interdisciplinary providers in oncology care settings at all of Ontario's 14 RCCs.
. Oncology nurses' attitudes and use of ESAS were measured using a 21-item investigator-developed questionnaire. Descriptive statistics and Kendall's tau-b or tau-c test were used for data analyses. Qualitative responses were analyzed using content analysis.
. Attitudes toward and self-reported use of standardized symptom screening and ESAS.
. More than half of the participants agreed that ESAS improves symptom screening, most said they would encourage their patients to complete ESAS, and most felt that managing symptoms is within their scope of practice and clinical responsibilities. Qualitative comments provided additional information elucidating the quantitative responses. Statistical analyses revealed that oncology nurses who have 10 years or less of work experience were more likely to agree that the use of standardized, valid instruments to screen for and assess symptoms should be considered best practice, ESAS improves symptom screening, and ESAS enables them to better manage patients' symptoms. No statistically significant difference was found between oncology-certified RNs and noncertified RNs on attitudes or reported use of ESAS.
. Implementing a population-based symptom screening approach is a major undertaking. The current study found that oncology nurses recognize the value of standardized screening, as demonstrated by their attitudes toward ESAS.
. Oncology nurses are integral to providing high

  19. Value Assessment of Artificial Wetland Derived from Mining Subsided Lake: A Case Study of Jiuli Lake Wetland in Xuzhou

    Directory of Open Access Journals (Sweden)

    Laijian Wang


    Full Text Available Mining subsided lakes are major obstacles for ecological restoration and resource reuse in mining regions. Transforming mining subsided lakes into artificial wetlands is an ecological restoration approach that has been attempted in China in recent years, but a value assessment of the approach still needs systematic research. This paper considers Jiuli Lake wetland, an artificial wetland derived from restoration of a mining subsided lake in plain area, as a case study. A value assessment model for the artificial wetland was established based on cost–benefit analysis by means of field monitoring, social surveys, GIS geostatistics, raster calculation methods, etc. Empirical analysis and calculations were performed on the case study region. The following conclusions were drawn: (1 after ecological restoration, ecosystem services of Jiuli Lake wetland which has become a national level wetland park yield positive values; (2 the improved environment of the Jiuli Lake wetland has a spillover effect on the price of surrounding land, resulting in land price appreciation; (3 using GIS geostatistics and raster calculation methods, the impact range, strength, and value of the spillover effect can be explicitly measured; (4 through the establishment of a value assessment model of the artificial wetland, incomes of the ecological restoration was found to be sufficient to cover the implementation costs, which provides a research foundation for economic feasibility of ecological restoration of mining subsided lakes.

  20. An assessement of the ecosystem health of Lake Victoria (East Africa)

    African Journals Online (AJOL)

    An assessement of the ecosystem health of Lake Victoria (East Africa): Current status, trends and impacts to fishery. ... complicated the ecosystem dynamics of Lake Victoria and pose serious uncertainties about its future stability and sustainability of the fisheries resources. Lake Victoria's future sustainability requires ...

  1. Climate Change Assessments for Lakes Region of Turkey

    Directory of Open Access Journals (Sweden)

    Ayten Erol


    Full Text Available Climate change is one of the most important challenges for forestry. Forests are known to be most efficient natural tools to ensure availability and quality of water in many regions. Besides, planning of forest resources towards water quality and quantity is essential in countries that are expected to face with more frequent drought periods in the next decades due to climate change. Watershed management concept has been supposed as the primary tool to plan natural resources in a more efficient and sustainable way by both academicians and practitioners to mitigate and adapt climate change. Forest cover among other land use types provides the best regulating mechanism to mitigate erosion, sedimentation, desertification, and pollution. In addition, climate change can potentially affect forest stand dynamics by influencing the availability of water resources. Therefore, the amount of forest cover in a watershed is an indicator of climate change mitigation and adaptation. Climate change is a concern and risk for the sustainability of water resources in Lakes Region of Turkey. The objective of this study is to make a comprehensive assessment in lake watersheds of the Lakes region considering the forest cover. For this purpose, the study gives a general view of trends in climatic parameters using Mann Kendall trend test. The results showed that Mann Kendall trend test for temperature and precipitation data is not enough to evaluate the magnitude of potential changes of climate in terms of forest cover. Understanding impacts of changes in temperature and precipitation on forest cover, runoff data should be evaluated with temperature and precipitation for watersheds of forest areas in Lakes Region.

  2. Assessing the distribution of volatile organic compounds using land use regression in Sarnia, "Chemical Valley", Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Luginaah Isaac N


    Full Text Available Abstract Background Land use regression (LUR modelling is proposed as a promising approach to meet some of the challenges of assessing the intra-urban spatial variability of ambient air pollutants in urban and industrial settings. However, most of the LUR models to date have focused on nitrogen oxides and particulate matter. This study aimed at developing LUR models to predict BTEX (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene concentrations in Sarnia, 'Chemical Valley', Ontario, and model the intra-urban variability of BTEX compounds in the city for a community health study. Method Using Organic Vapour Monitors, pollutants were monitored at 39 locations across the city of Sarnia for 2 weeks in October 2005. LUR models were developed to generate predictor variables that best estimate BTEX concentrations. Results Industrial area, dwelling counts, and highways adequately explained most of the variability of BTEX concentrations (R2: 0.78 – 0.81. Correlations between measured BTEX compounds were high (> 0.75. Although most of the predictor variables (e.g. land use were similar in all the models, their individual contributions to the models were different. Conclusion Yielding potentially different health effects than nitrogen oxides and particulate matter, modelling other air pollutants is essential for a better understanding of the link between air pollution and health. The LUR models developed in these analyses will be used for estimating outdoor exposure to BTEX for a larger community health study aimed at examining the determinants of health in Sarnia.

  3. Assessment and Simulation of Glacier Lake Outburst Floods for Longbasaba and Pida Lakes, China

    National Research Council Canada - National Science Library

    Wang Xin; Liu Shiyin; Guo Wanqin; Xu Junli


    Abstract Longbasaba and Pida lakes are two moraine-dammed lakes located at the headwaters of the Geiqu River, a tributary of the Pumqu River in the Chinese Himalayas, at an elevation of about 5700 m...

  4. Life cycle cost and economic assessment of biochar-based bioenergy production and biochar land application in Northwestern Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Krish Homagain


    Full Text Available Background Replacement of fossil fuel based energy with biochar-based bioenergy production can help reduce greenhouse gas emissions while mitigating the adverse impacts of climate change and global warming. However, the production of biochar-based bioenergy depends on a sustainable supply of biomass. Although, Northwestern Ontario has a rich and sustainable supply of woody biomass, a comprehensive life cycle cost and economic assessment of biochar-based bioenergy production technology has not been done so far in the region. Methods In this paper, we conducted a thorough life cycle cost assessment (LCCA of biochar-based bioenergy production and its land application under four different scenarios: 1 biochar production with low feedstock availability; 2 biochar production with high feedstock availability; 3 biochar production with low feedstock availability and its land application; and 4 biochar production with high feedstock availability and its land application- using SimaPro®, EIOLCA® software and spreadsheet modeling. Based on the LCCA results, we further conducted an economic assessment for the break-even and viability of this technology over the project period. Results It was found that the economic viability of biochar-based bioenergy production system within the life cycle analysis system boundary based on study assumptions is directly dependent on costs of pyrolysis, feedstock processing (drying, grinding and pelletization and collection on site and the value of total carbon offset provided by the system. Sensitivity analysis of transportation distance and different values of C offset showed that the system is profitable in case of high biomass availability within 200 km and when the cost of carbon sequestration exceeds CAD $60 per tonne of equivalent carbon (CO2e. Conclusions Biochar-based bioenergy system is economically viable when life cycle costs and environmental assumptions are accounted for. This study provides a medium scale

  5. Assessing landscape and contaminant point-sources as spatial determinants of water quality in the Vermilion River System, Ontario, Canada. (United States)

    Strangway, Carrie; Bowman, Michelle F; Kirkwood, Andrea E


    The Vermilion River and major tributaries (VRMT) are located in the Vermilion watershed (4272 km(2)) in north-central Ontario, Canada. This watershed not only is dominated by natural land-cover but also has a legacy of mining and other development activities. The VRMT receive various point (e.g., sewage effluent) and non-point (e.g., mining activity runoff) inputs, in addition to flow regulation features. Further development in the Vermilion watershed has been proposed, raising concerns about cumulative impacts to ecosystem health in the VRMT. Due to the lack of historical assessments on riverine-health in the VRMT, a comprehensive suite of water quality parameters was collected monthly at 28 sites during the ice-free period of 2013 and 2014. Canadian water quality guidelines and objectives were not met by an assortment of water quality parameters, including nutrients and metals. This demonstrates that the VRMT is an impacted system with several pollution hotspots, particularly downstream of wastewater treatment facilities. Water quality throughout the river system appeared to be influenced by three distinct land-cover categories: forest, barren, and agriculture. Three spatial pathway models (geographical, topographical, and river network) were employed to assess the complex interactions between spatial pathways, stressors, and water quality condition. Topographical landscape analyses were performed at five different scales, where the strongest relationships between water quality and land-use occurred at the catchment scale. Sites on the main stem of Junction Creek, a tributary impacted by industrial and urban development, had above average concentrations for the majority of water quality parameters measured, including metals and nitrogen. The river network pathway (i.e., asymmetric eigenvector map (AEM)) and topographical feature (i.e., catchment land-use) models explained most of the variation in water quality (62.2%), indicating that they may be useful tools in

  6. Great Lakes Ice Charts (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  7. Assessment of glacial lake development and prospects of outburst susceptibility: Chamlang South Glacier, eastern Nepal Himalaya


    Damodar Lamsal; Takanobu Sawagaki; Teiji Watanabe; Alton C. Byers


    Chamlang South Tsho has been identified as one of the six high-priority glacial lakes in terms of glacial lake outburst flood (GLOF) danger in Nepal Himalaya, despite the fact that no detailed investigations of the lake had been hitherto undertaken. We conducted detailed mapping of the lake and its surroundings along with field surveys in October 2009 to determine the developmental history of Chamlang South Tsho and to assess its potential for GLOF. The lake expanded rapidly between 1964 (0.0...

  8. Phytoplankton and Eutrophication Degree Assessment of Baiyangdian Lake Wetland, China (United States)

    Wang, Xing; Wang, Yu; Liu, Lusan; Shu, Jianmin; Zhu, Yanzhong; Zhou, Juan


    Eight typical sampling sites were chosen to investigate the phytoplankton community structure and to assess the eutrophication degree of Baiyangdian Lake in 2009. Our results showed that among the total 133 species identified, Cyanophyta, Chlorophyta, and Bacillariophyta dominated the phytoplankton community. In spring, Chlorophyta and Bacillariophyta were the dominant phyla, and the dominant species included Chlorella sp., Chroomonas acuta Uterm., and Microcystis incerta Lemm.; the density of the phytoplankton ranged from 496 × 104 to 6256 × 104 cells/L with an average of 2384 × 104 cells/L. However, Chlorophyta and Cyanophyta became the dominant phyla in summer, and the dominant species were Chlorella sp., Leptolyngbya valderiana Anagn., and Nephrocytium agardhianum Nageli.; the density of the phytoplankton varied from 318 × 104 to 4630 × 104 cells/L with an average of 1785 × 104 cells/L. The density of the phytoplankton has increased significantly compared to the previous investigations in 2005. The index of Carlson nutritional status (TSIM) and the dominant genus assessment indicated that the majority of Baiyangdian Lake was in eutrophic state. PMID:23983633

  9. Changes in the parkland-boreal forest boundary in northwestern Ontario over the Holocene (United States)

    Moos, Melissa T.; Cumming, Brian F.


    Changes in vegetation were tracked from a well-dated sediment core from a boreal lake, Lake 239, at ˜200-year resolution over the Holocene. This presently oligotrophic lake is located ˜100-km east from the present-day parkland-forest ecotone in northwestern Ontario. Near-shore sediment core transects from Lake 239 have previously shown this lake was at least 8-m lower than present in the mid-Holocene, or ˜58% less lake volume in comparison to today. Large shifts were expected in the terrestrial vegetation if the low lake levels were related to climate. The core from Lake 239 shows increases in the relative abundance and concentration of pollen such as Cupressaceae and Ambrosia, indicating a more open boreal forest between ˜4500-8000 cal yr BP. Pollen-based inferences of average, summer and winter temperatures suggest that temperatures were on average up to 1-2 °C warmer than today, with winter temperatures up to 4 °C warmer. The pollen inferences also suggest enhanced precipitation, likely in the summer, but with an overall increase in evaporation and evapotranspiration resulting in reduced effective moisture. To assess regional climate changes, pollen-based reconstructions of temperature and precipitation were developed and synthesized from sediment cores from eight previously published lakes, from which pollen sites were available to both the west and east of Lake 239, spanning present-day prairie lakes to forested lakes up to 300 km east of the prairie-boreal ecotone. All sites show shifts in pollen assemblages that indicate a warm mid-Holocene period; prairie sites west of the Experimental Lakes Area (ELA) show mid-Holocene decreases in precipitation relative to today, whereas sites near or east of ELA show consistent increases in precipitation, but with increased temperatures and enhanced evaporation during the mid-Holocene.

  10. Stock assessment of fishery target species in Lake Koka, Ethiopia

    Directory of Open Access Journals (Sweden)

    Gashaw Tesfaye


    Full Text Available Effective management is essential for small-scale fisheries to continue providing food and livelihoods for households, particularly in developing countries where other options are often limited. Studies on the population dynamics and stock assessment on fishery target species are thus imperative to sustain their fisheries and the benefits for the society. In Lake Koka (Ethiopia, very little is known about the vital population parameters and exploitation status of the fishery target species: tilapia Oreochromis niloticus,common carp Cyprinus carpióand catfish Clarias gariepinus.Our study, therefore, aimed at determining the vital population parameters and assessing the status of these target species in Lake Koka using length frequency data collected quarterly from commercial catches from 2007-2012. A total of 20 097 fish specimens (distributed as 7 933 tilapia, 6 025 catfish and 6 139 common carp were measured for the analysis. Von Bertalanffy growth parameters and their confidence intervals were determined from modal progression analysis using ELEFAN I and applying the jackknife technique. Mortality parameters were determined from length-converted catch curves and empirical models. The exploitation status of these target species were then assessed by computing exploitation rates (E from mortality parameters as well as from size indicators i.e., assessing the size distribution of fish catches relative to the size at maturity (L m,the size that provides maximum cohort biomass (Lopt and the abundance of mega-spawners. The mean value of growth parameters L x, Kand the growth performance index 0' were 44.5 cm, 0.41/year and 2.90 for O. niloticus,74.1 cm, 0.28/year and 3.19 for C. carpioand 121.9 cm, 0.16/year and 3.36 for C. gariepinus,respectively. The 95 % confidence intervals of the estimates were also computed. Total mortality (Z estimates were 1.47, 0.83 and 0.72/year for O. niloticus, C. carpioand C. gariepinus,respectively. Our study suggest

  11. Assessment of hazard metrics for predicting field benthic invertebrate toxicity in the Detroit River, Ontario, Canada. (United States)

    McPhedran, Kerry N; Grgicak-Mannion, Alice; Paterson, Gord; Briggs, Ted; Ciborowski, Jan Jh; Haffner, G Douglas; Drouillard, Ken G


    Numerical sediment quality guidelines (SQGs) are frequently used to interpret site-specific sediment chemistry and predict potential toxicity to benthic communities. These SQGs are useful for a screening line of evidence (LOE) that can be combined with other LOEs in a full weight of evidence (WOE) assessment of impacted sites. Three common multichemical hazard quotient methods (probable effect concentration [PEC]-Qavg , PEC-Qmet , and PEC-Qsum ) and a novel (hazard score [HZD]) approach were used in conjunction with a consensus-based set of SQGs to evaluate the ability of different scoring metrics to predict the biological effects of sediment contamination under field conditions. Multivariate analyses were first used to categorize river sediments into distinct habitats based on a set of physicochemical parameters to include gravel, low and high flow sand, and silt. For high flow sand and gravel, no significant dose-response relationships between numerically dominant species and various toxicity metric scores were observed. Significant dose-response relationships were observed for chironomid abundances and toxicity scores in low flow sand and silt habitats. For silt habitats, the HZD scoring metric provided the best predictor of chironomid abundances compared to various PEC-Q methods according to goodness-of-fit tests. For low flow sand habitats, PEC-Qsum followed by HZD, provided the best predictors of chironomid abundance. Differences in apparent chironomid toxicity between the 2 habitats suggest habitat-specific differences in chemical bioavailability and indicator taxa sensitivity. Using an IBI method, the HZD, PEC-Qavg , and PEC-Qmet approaches provided reasonable correlations with calculated IBI values in both silt and low flow sand habitats but not for gravel or high flow sands. Computation differences between the various multi-chemical toxicity scoring metrics and how this contributes to bias in different estimates of chemical mixture toxicity scores are

  12. Assessing risk of non-compliance of phosphorus standards for lakes in England and Wales (United States)

    Duethmann, D.; Anthony, S.; Carvalho, L.; Spears, B.


    High population densities, use of inorganic fertilizer and intensive livestock agriculture have increased phosphorus loads to lakes, and accelerated eutrophication is a major pressure for many lakes. The EC Water Framework Directive (WFD) requires that good chemical and ecological quality is restored in all surface water bodies by 2015. Total phosphorus (TP) standards for lakes in England and Wales have been agreed recently, and our aim was to estimate what percentage of lakes in England and Wales is at risk of failing these standards. With measured lake phosphorus concentrations only being available for a small number of lakes, such an assessment had to be model based. The study also makes a source apportionment of phosphorus inputs into lakes. Phosphorus loads were estimated from a range of sources including agricultural loads, sewage effluents, septic tanks, diffuse urban sources, atmospheric deposition, groundwater and bank erosion. Lake phosphorus concentrations were predicted using the Vollenweider model, and the model framework was satisfactorily tested against available observed lake concentration data. Even though predictions for individual lakes remain uncertain, results for a population of lakes are considered as sufficiently robust. A scenario analysis was carried out to investigate to what extent reductions in phosphorus loads would increase the number of lakes achieving good ecological status in terms of TP standards. Applying the model to all lakes in England and Wales greater than 1 ha, it was calculated that under current conditions roughly two thirds of the lakes would fail the good ecological status with respect to phosphorus. According to our estimates, agricultural phosphorus loads represent the most frequent dominant source for the majority of catchments, but diffuse urban runoff also is important in many lakes. Sewage effluents are the most frequent dominant source for large lake catchments greater than 100 km². The evaluation in terms of

  13. A new remote hazard and risk assessment framework for glacial lakes in the Nepal Himalaya (United States)

    Rounce, David R.; McKinney, Daene C.; Lala, Jonathan M.; Byers, Alton C.; Watson, C. Scott


    Glacial lake outburst floods (GLOFs) pose a significant threat to downstream communities and infrastructure due to their potential to rapidly unleash stored lake water. The most common triggers of these GLOFs are mass movement entering the lake and/or the self-destruction of the terminal moraine due to hydrostatic pressures or a buried ice core. This study initially uses previous qualitative and quantitative assessments to understand the hazards associated with eight glacial lakes in the Nepal Himalaya that are widely considered to be highly dangerous. The previous assessments yield conflicting classifications with respect to each glacial lake, which spurred the development of a new holistic, reproducible, and objective approach based solely on remotely sensed data. This remote hazard assessment analyzes mass movement entering the lake, the stability of the moraine, and lake growth in conjunction with a geometric GLOF to determine the downstream impacts such that the present and future risk associated with each glacial lake may be quantified. The new approach is developed within a hazard, risk, and management action framework with the aim that this remote assessment may guide future field campaigns, modeling efforts, and ultimately risk-mitigation strategies. The remote assessment was found to provide valuable information regarding the hazards faced by each glacial lake and results were discussed within the context of the current state of knowledge to help guide future efforts.

  14. An accuracy assessment of forest disturbance mapping in the western Great Lakes (United States)

    P.L. Zimmerman; I.W. Housman; C.H. Perry; R.A. Chastain; J.B. Webb; M.V. Finco


    The increasing availability of satellite imagery has spurred the production of thematic land cover maps based on satellite data. These maps are more valuable to the scientific community and land managers when the accuracy of their classifications has been assessed. Here, we assessed the accuracy of a map of forest disturbance in the watersheds of Lake Superior and Lake...

  15. Survey and assessment of post volcanic activities of a young caldera lake, Lake Cuicocha, Ecuador

    Directory of Open Access Journals (Sweden)

    G. Gunkel


    Full Text Available Cuicocha is a young volcano adjacent to the inactive Pleistocene Cotacachi volcano complex, located in the western cordilleras of the Ecuadorian Andes. A series of eruptions with intensive ash emission and collapse of the caldera occurred around 4500–3000 y BP. A crater 3.2 km in diameter and a maximum depth of 450 m was formed. Further eruptions of the volcano occurred 1300 y BP and formed four smaller domes within the caldera. Over the last few hundred years, a caldera lake has developed, with a maximum depth of 148 m. The lake water is characterized by sodium carbonate with elevated concentrations of manganese, calcium and chloride. Nowadays, an emission of gases, mainly CO2, and an input of warm spring water occur in Lake Cuicocha. The zone of high activity is in the western basin of the lake at a depth of 78 m, and continuous gas emissions with sediment resuspension were observed using sonar. In the hypolimnion of the lake, CO2 accumulation occurs up to 0.2% saturation, but the risk of a limnic eruption can be excluded at present. The lake possesses monomictic stratification behaviour, and during overturn an intensive gas exchange with the atmosphere occurs. Investigations concerning the sedimentation processes of the lake suggest only a thin sediment layer of up to 10–20 cm in the deeper lake basin; in the western bay, in the area of gas emissions, the lake bottom is partly depleted of sediment in the form of holes, and no lake colmation exists. Decreases in the lake water level of about 30 cm y−1 indicate a percolation of water into fractures and fissures of the volcano, triggered by a nearby earthquake in 1987.

  16. Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. L. [Texas AgriLife Research, College Station, TX (United States); Roelke, Daniel [Texas AgriLife Research, College Station, TX (United States); Brooks, Bryan [Texas AgriLife Research, College Station, TX (United States); Grover, James [Texas AgriLife Research, College Station, TX (United States)


    A team of Texas AgriLife Research, Baylor University and University of Texas at Arlington researchers studied the biology and ecology of Prymnesium parvum (golden algae) in Texas lakes using a three-fold approach that involved system-wide monitoring, experimentation at the microcosm and mesocosm scales, and mathematical modeling. The following are conclusions, to date, regarding this organism's ecology and potential strategies for mitigation of blooms by this organism. In-lake monitoring revealed that golden algae are present throughout the year, even in lakes where blooms do not occur. Compilation of our field monitoring data with data collected by Texas Parks and Wildlife and Brazos River Authority (a period spanning a decade) revealed that inflow and salinity variables affect bloom formations. Thresholds for algae populations vary per lake, likely due to adaptations to local conditions, and also to variations in lake-basin morphometry, especially the presence of coves that may serve as hydraulic storage zones for P. parvum populations. More specifically, our in-lake monitoring showed that the highly toxic bloom that occurred in Lake Granbury in the winter of 2006/2007 was eliminated by increased river inflow events. The bloom was flushed from the system. The lower salinities that resulted contributed to golden algae not blooming in the following years. However, flushing is not an absolute requirement for bloom termination. Laboratory experiments have shown that growth of golden algae can occur at salinities ~1-2 psu but only when temperatures are also low. This helps to explain why blooms are possible during winter months in Texas lakes. Our in-lake experiments in Lake Whitney and Lake Waco, as well as our laboratory experiments, revealed that cyanobacteria, or some other bacteria capable of producing algicides, were able to prevent golden algae from blooming. Identification of this organism is a high priority as it may be a key to managing golden algae

  17. Improving assessment accuracy for lake biological condition by classifying lakes with diatom typology, varying metrics and modeling multimetric indices. (United States)

    Liu, Bo; Stevenson, R Jan


    Site grouping by regions or typologies, site-specific modeling and varying metrics among site groups are four approaches that account for natural variation, which can be a major source of error in ecological assessments. Using a data set from the 2007 National Lakes Assessment project of the USEPA, we compared performances of multimetric indices (MMI) of biological condition that were developed: (1) with different lake grouping methods, ecoregions or diatom typologies; (2) by varying or not varying metrics among site groups; and (3) with different statistical techniques for modeling diatom metric values expected for minimally disturbed condition for each lake. Hierarchical modeling of MMIs, i.e. grouping sites by ecoregions or typologies and then modeling natural variability in metrics among lakes within groups, substantially improved MMI performance compared to using either ecoregions or site-specific modeling alone. Compared with MMIs based on ecoregion site groups, MMI precision and sensitivity to human disturbance were better when sites were grouped by diatom typologies and assessing performance nationwide. However, when MMI performance was evaluated at site group levels, as some government agencies often do, there was little difference in MMI performance between the two site grouping methods. Low numbers of reference and highly impacted sites in some typology groups likely limited MMI performance at the group level of analysis. Varying metrics among site groups did not improve MMI performance. Random forest models for site-specific expected metric values performed better than classification and regression tree and multiple linear regression, except when numbers of reference sites were small in site groups. Then classification and regression tree models were most precise. Based on our results, we recommend hierarchical modeling in future large scale lake assessments where lakes are grouped by ecoregions or diatom typologies and site-specific metric models are

  18. Water quality assessment based on the water quality index method in Lake Poyang: The largest freshwater lake in China. (United States)

    Wu, Zhaoshi; Zhang, Dawen; Cai, Yongjiu; Wang, Xiaolong; Zhang, Lu; Chen, Yuwei


    Twenty-four samplings were conducted every 3 months at 15 sites from January 2009 to October 2014 in Lake Poyang, and 20 parameters were analyzed and classified into three groups (toxic metals, easily treated parameters, and others). The assessment results based on water quality index (WQI) showed that the water quality in Lake Poyang was generally "moderate", according to the classification of the surface water quality standard (GB3838-2002) in China, but a deteriorating trend was observed at the interannual scale. Seasonally, the water quality was best in summer and worst in winter. Easily treated parameters generally determined the WQI value in the assessment, especially total nitrogen (TN) and total phosphorus (TP), while toxic metals and other parameters in Lake Poyang were generally at low and safe levels for drinking water. Water level (WL) has a net positive effect on water quality in Lake Poyang through dilution of environmental parameters, which in practice means TN. Consequently, local management agencies should pay more attention to nutrient concentrations during the monitoring schedule, as well as during the low-water periods which manifest a relatively bad water quality state, especially with the prevailing low WL observed recently in Lake Poyang.

  19. Water quality assessment in a shallow lake used for tourism

    Directory of Open Access Journals (Sweden)

    Dembowska Ewa A.


    Full Text Available The routine evaluation of water quality is limited to lakes with the largest area. In Poland, only lakes with an area exceeding 50 hectares are monitored by the State Environmental Monitoring System. For many local communities, however, small lakes are more important. This applies mainly to areas with a small number of lakes, where even the smallest lakes are used for various purposes. This paper presents the results of phytoplankton analysis in a small and shallow lake used for recreation. The study was conducted at three sites located in different parts of the lake. A total of 122 algae taxa were identified in the phytoplankton, mainly diatoms and green algae. The most constant taxa in the lake were: Stephanodiscus hantzschii, Desmodesmus communis, Pediastrum tetras and Crucigenia tetrapedia. The average phytoplankton biomass was 37 mg l−1. The maximum biomass, almost 140 mg dm−3, was recorded in late July at the site located near the beach. At that time, there was a massive cyanobacterial bloom composed of Microcystis wesenbergii and Aphanizomenon issatschenkoi. Based on these studies, the lake should be classified as hypertrophic with bad ecological status. This lake should not be used for recreational purposes in the current state.

  20. A new remote hazard and risk assessment framework for glacial lakes in the Nepal Himalaya


    Rounce, DR; McKinney, DC; Lala, JM; Byers, AC; Watson, CS


    Glacial lake outburst floods (GLOFs) pose a significant threat to downstream communities and infrastructure due to their potential to rapidly unleash stored lake water. The most common triggers of these GLOFs are mass movement entering the lake and/or the self-destruction of the terminal moraine due to hydrostatic pressures or a buried ice core. This study initially uses previous qualitative and quantitative assessments to understand the hazards associated with eight glacial...

  1. Selecting indicators to assess the fisheries of Lake Malawi and Lake Malombe: Knowledge base and evaluative capacity

    NARCIS (Netherlands)

    Zwieten, van P.A.M.; Banda, M.; Kolding, J.


    The provision of management information on the fisheries of Lakes Malawi and Malombe has been characterised by top–down controlled single species steady-state assessment techniques originating from single gear industrial fisheries but applied to an open access highly diverse and adaptive small-scale

  2. An Assessment of the Canadian Federal-Provincial Crop Production Insurance Program under Future Climate Change Scenarios in Ontario


    Li, Shuang; Ker, Alan P.


    Research and observations indicate climate change has and will have an impact on Ontario field crop production. Little research has been done to forecast how climate change might influence the Canadian Federal-Provincial Crop Insurance program, including its premium rates and reserve fund balances, in the future decades. This paper proposes using a mixture of two normal yield probability distribution model to model crop yield conditions under hypothetical climate change scenarios. Then superi...

  3. Assessment of glacial lake development and prospects of outburst susceptibility: Chamlang South Glacier, eastern Nepal Himalaya

    Directory of Open Access Journals (Sweden)

    Damodar Lamsal


    Full Text Available Chamlang South Tsho has been identified as one of the six high-priority glacial lakes in terms of glacial lake outburst flood (GLOF danger in Nepal Himalaya, despite the fact that no detailed investigations of the lake had been hitherto undertaken. We conducted detailed mapping of the lake and its surroundings along with field surveys in October 2009 to determine the developmental history of Chamlang South Tsho and to assess its potential for GLOF. The lake expanded rapidly between 1964 (0.04 km2 and 2000 (0.86 km2 and has been stable ever since. Future lake expansion is improbable as its sides are confined by relatively stable landforms. The lake is 87-m deep with a water volume of approximately 34.9–35.6 × 106 m3. Hanging glaciers on the steep surrounding mountain slopes and prominent seepage water in the terminal moraine dam could be potential triggers for a future outburst flood. Additionally, the debris-covered dead-ice dam, which is higher than the lake water level, is narrow and low; therefore, it could be overtopped easily by surge waves. Furthermore, the pronounced difference in elevation between the lake and the base of the terminal moraine dam makes the lake susceptible for a large flood.

  4. Assessing Glacial Lake Outburst Flood Hazard in the Nepal Himalayas using Satellite Imagery and Hydraulic Models (United States)

    Rounce, D.; McKinney, D. C.


    The last half century has witnessed considerable glacier melt that has led to the formation of large glacial lakes. These glacial lakes typically form behind terminal moraines comprising loose boulders, debris, and soil, which are susceptible to fail and cause a glacial lake outburst flood (GLOF). These lakes also act as a heat sink that accelerates glacier melt and in many cases is accompanied by rapid areal expansion. As these glacial lakes continue to grow, their hazard also increases due to the increase in potential flood volume and the lakes' proximity to triggering events such as avalanches and landslides. Despite the large threat these lakes may pose to downstream communities, there are few detailed studies that combine satellite imagery with hydraulic models to present a holistic understanding of the GLOF hazard. The aim of this work is to assess the GLOF hazard of glacial lakes in Nepal using a holistic approach based on a combination of satellite imagery and hydraulic models. Imja Lake will be the primary focus of the modeling efforts, but the methods will be developed in a manner that is transferable to other potentially dangerous glacial lakes in Nepal.

  5. Assessment of Wetland Hydrological Dynamics in a Modified Catchment Basin: Case of Lake Buninjon, Victoria, Australia. (United States)

    Yihdego, Yohannes; Webb, John A


      The common method to estimate lake levels is the water balance equation, where water input and output result in lake storage and water level changes. However, all water balance components cannot always be quickly assessed, such as due to significant modification of the catchment area. A method that assesses general changes in lake level can be a useful tool in examining why lakes have different lake level variation patterns. Assessment of wetlands using the dynamics of the historical hydrological and hydrogeological data set can provide important insights into variations in wetland levels in different parts of the world. A case study from a saline landscape, Lake Buninjon, Australia, is presented. The aim of the present study was to determine how climate, river regime, and lake hydrological properties independently influence lake water levels and salinity, leaving the discrepancy, for the effect of the non-climatic/catchment modification in the past and the model shows that surface inflow is most sensitive variable. The method, together with the analysis and interpretation, might be of interest to wider community to assess its response to natural/anthropogenic stress and decision choices for its ecological, social, scientific value, and mitigation measures to safe guard the wetland biodiversity in a catchment basin.

  6. National Aquatic Resource Surveys (NARS) N/P Values for Lakes – National Lake Assessment (United States)

    U.S. Environmental Protection Agency — The National Aquatic Resource Survey (NARS) findings for nutrients in streams and lakes highlight that nutrient pollution is widespread across the United States and...

  7. Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study. (United States)

    Li, Qinqin; Hu, Weiping; Zhai, Shuhua


    Algal blooms have recently become one of the most serious environmental problems in eutrophic freshwater ecosystems worldwide. Although many observation and simulation approaches have been applied to predict algal blooms, few studies have addressed the alert levels of algal blooms using integrative indicators in a large lake with multiple service function and significant horizontal heterogeneity. This study developed an integrative indicator assessment system (IIAS) to rank the alert level of algal blooms. In the IIAS, algal biomass, area percentage, distance from drinking water intake points, distance from scenic zones and duration of algal bloom were used as indicators to calculate a comprehensive alert level, which was classified into five grades (Vigilance, Low, Moderate, High, and Severe). Lake Taihu was taken as a case study to assess the comprehensive alert level of algal blooms in 2007 and 2010. The comprehensive alert level showed obvious spatial-temporal patterns, with an acceptable accuracy in Lake Taihu. The comprehensive alert levels were relatively higher in typical phytoplankton subzones than typical hydrophytes subzones and are more sensitive to weight factor in the northern and western subzones where high biomass usually occurs. Case study showed a very good application of the proposed comprehensive alert level assessment methodology, which can be adjusted to predict the degree of hazard of algal blooms in multi-service function large lakes to help the government and decision makers to act to prevent the disaster from algal bloom spreading.

  8. Assessment of the fish tumor beneficial use impairment in brown bullhead (Ameiurus nebulosus) at selected Great Lakes Areas of Concern (United States)

    Blazer, Vicki; Mazik, Patricia M.; Iwanowicz, Luke R.; Braham, Ryan P.; Hahn, Cassidy M.; Walsh, Heather L.; Sperry, Adam J.


    A total of 878 adult Brown Bullhead were collected at 11 sites within the Lake Erie and Lake Ontario drainages from 2011 to 2013. The sites included seven Areas of Concern (AOC; 670 individuals), one delisted AOC (50 individuals) and three non-AOC sites (158 individuals) used as reference sites. These fish were used to assess the “fish tumor or other deformities” beneficial use impairment. Fish were anesthetized, weighed, measured and any external abnormalities documented and removed. Abnormal orocutaneous and barbel tissue, as well as five to eight pieces of liver, were preserved for histopathological analyses. Otoliths were removed and used for age analyses. Visible external abnormalities included reddened (raised or eroded), melanistic areas and raised growths on lips, body surface, fins and barbels. Microscopically, these raised growths included papilloma, squamous cell carcinoma, osteoma and osteosarcoma. Proliferative lesions of the liver included bile duct hyperplasia, foci of cellular alteration, bile duct (cholangioma, cholangiocarcinoma) and hepatocellular (adenoma, hepatic cell carcinoma) neoplasia. The two reference sites (Long Point Inner Bay, Conneaut Creek), at which 30 or more bullhead were collected had a skin tumor prevalence of 10% or less and liver tumor prevalence of 4% or less. Presque Isle Bay, recently delisted, had a similar liver tumor prevalence (4%) and slightly higher prevalence (12%) of skin tumors. The prevalence of skin neoplasms was 15% or less at sites in the Black River, Cuyahoga River and Maumee AOCs, while more than 20% of the bullheads from the Rochester Embayment, Niagara River, Detroit River and Ashtabula River AOCs had skin tumors. The prevalence of liver tumors was greater than 4% at all AOC sites except the Old Channel site at the Cuyahoga River AOC, Wolf Creek within the Maumee AOC and the upper and lower sites within the Niagara River AOC.

  9. Targets set to reduce Lake Erie algae (United States)

    Evans, Mary


    In February 2016, the Great Lakes Executive Committee, which oversees the implementation of the Great Lakes Water Quality Agreement (GLWQA) between the U.S. and Canada, approved phosphorus loading targets for Lake Erie to reduce the size of harmful algal blooms (HABs), reduce the presence of the low oxygen zone in the central basin, and protect nearshore water quality. The targets are set with respect to the nutrient loads calculated for 2008. To reduce the impacts of HABs on Lake Erie a target was set of a 40 percent reduction in total and soluble reactive phosphorus loads in the spring from two Canadian rivers and several Michigan and Ohio rivers, especially the Maumee River ( finalptargets-ciblesfinalesdep/). States and the province of Ontario are already developing Domestic Action Plans to accomplish the reductions and scientists are developing research and monitoring plans to assess progress.

  10. Site specific risk assessment of an energy-from-waste thermal treatment facility in Durham Region, Ontario, Canada. Part A: Human health risk assessment. (United States)

    Ollson, Christopher A; Knopper, Loren D; Whitfield Aslund, Melissa L; Jayasinghe, Ruwan


    The regions of Durham and York in Ontario, Canada have partnered to construct an energy-from-waste thermal treatment facility as part of a long term strategy for the management of their municipal solid waste. This paper presents the results of a comprehensive human health risk assessment for this facility. This assessment was based on extensive sampling of baseline environmental conditions (e.g., collection and analysis of air, soil, water, and biota samples) as well as detailed site specific modeling to predict facility-related emissions of 87 identified contaminants of potential concern. Emissions were estimated for both the approved initial operating design capacity of the facility (140,000 tonnes per year) and for the maximum design capacity (400,000 tonnes per year). For the 140,000 tonnes per year scenario, this assessment indicated that facility-related emissions are unlikely to cause adverse health risks to local residents, farmers, or other receptors (e.g., recreational users). For the 400,000 tonnes per year scenarios, slightly elevated risks were noted with respect to inhalation (hydrogen chloride) and infant consumption of breast milk (dioxins and furans), but only during predicted 'upset conditions' (i.e. facility start-up, shutdown, and loss of air pollution control) that represent unusual and/or transient occurrences. However, current provincial regulations require that additional environmental screening would be mandatory prior to expansion of the facility beyond the initial approved capacity (140,000 tonnes per year). Therefore, the potential risks due to upset conditions for the 400,000 tonnes per year scenario should be more closely investigated if future expansion is pursued. © 2013.

  11. Hazard risk and alert level in assessment of a rehabilitated urban lake

    Directory of Open Access Journals (Sweden)

    TÖRÖK Liliana


    Full Text Available Ciuperca Lake, located in the floodplain area of the lower Danube, suffered a lot of interventions over time due to human activity. Man-made interventions started in 1830 and during the time changes have been made in shape, functions and role of the lake and the surrounding wetlands. Drainage, cleaning the lake, concrete banks on the lake shores transformed Ciuperca Lake from natural lake into a flood-protection area for the city and later into a recreational area for the citizens. Since 2011 the lake has been used as a recreational bathing area of Tulcea city. Due to these aspects two problem arise: the lack of information for the local authorities on water quality and on the dangers for exposing the population to the blooming of algae (if these later ones would take place. The phytoplankton of Ciuperca Lake is dominated by cyanobacteria having a wide range of temperature tolerance, their presence in water being recorded even under the ice coverage and has a great development-potential. The author’s assessment on hazard status and alert level could provide a pertinent analysis of the results of the rehabilitation program for improving the water quality of Ciuperca Lake and a better understanding of the necessity to include the inland water used for recreational purpose into a national monitoring program.

  12. Lake Whitney Comprehensive Water Quality Assessment, Phase 1B- Physical and Biological Assessment (USDOE)

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Robert D; Byars, Bruce W


    assessment of knowledge of watershed and water quality related issues by local residents and stakeholders of Lake Whitney and design an intervention educational program to address any deficiencies discovered. Phase IA was funded primarily from EPA Cooperative Agreement X7-9769 8901-0. Phase IC (USEPA, QAPP Study Element 5) of this research focused on the ambient toxicity of the reservoir with respect to periodic blooms of golden algae. Phase IC was funded primarily from Cooperative Agreement EM-96638001. Phase 1B (USDOE, Study Elements 6-11) complemented work being done via EPA funding on study elements 1-5 and added five new study elements: 6) Salinity Transport in the Brazos Watershed to Lake Whitney; 7) Bacterial Assessment; 8) Organic Contaminant Analysis on Lake Whitney; 9) Plankton Photosynthesis; 10) Lake Whitney Resident Knowledge Assessment; and 11) Engineering Scoping Perspective: Recommendations for Use.

  13. An Assessment of the Expected Cost-Effectiveness of Quadrivalent Influenza Vaccines in Ontario, Canada Using a Static Model.

    Directory of Open Access Journals (Sweden)

    Ayman Chit

    Full Text Available Ontario, Canada, immunizes against influenza using a trivalent inactivated influenza vaccine (IIV3 under a Universal Influenza Immunization Program (UIIP. The UIIP offers IIV3 free-of-charge to all Ontarians over 6 months of age. A newly approved quadrivalent inactivated influenza vaccine (IIV4 offers wider protection against influenza B disease. We explored the expected cost-utility and budget impact of replacing IIV3 with IIV4, within the context of Ontario's UIIP, using a probabilistic and static cost-utility model. Wherever possible, epidemiological and cost data were obtained from Ontario sources. Canadian or U.S. sources were used when Ontario data were not available. Vaccine efficacy for IIV3 was obtained from the literature. IIV4 efficacy was derived from meta-analysis of strain-specific vaccine efficacy. Conservatively, herd protection was not considered. In the base case, we used IIV3 and IIV4 prices of $5.5/dose and $7/dose, respectively. We conducted a sensitivity analysis on the price of IIV4, as well as standard univariate and multivariate statistical uncertainty analyses. Over a typical influenza season, relative to IIV3, IIV4 is expected to avert an additional 2,516 influenza cases, 1,683 influenza-associated medical visits, 27 influenza-associated hospitalizations, and 5 influenza-associated deaths. From a societal perspective, IIV4 would generate 76 more Quality Adjusted Life Years (QALYs and a net societal budget impact of $4,784,112. The incremental cost effectiveness ratio for this comparison was $63,773/QALY. IIV4 remains cost-effective up to a 53% price premium over IIV3. A probabilistic sensitivity analysis showed that IIV4 was cost-effective with a probability of 65% for a threshold of $100,000/QALY gained. IIV4 is expected to achieve reductions in influenza-related morbidity and mortality compared to IIV3. Despite not accounting for herd protection, IIV4 is still expected to be a cost-effective alternative to IIV3 up to

  14. Quantitative assessment of Urmia Lake water using spaceborne multisensor data and 3D modeling. (United States)

    Jeihouni, Mehrdad; Toomanian, Ara; Alavipanah, Seyed Kazem; Hamzeh, Saeid


    Preserving aquatic ecosystems and water resources management is crucial in arid and semi-arid regions for anthropogenic reasons and climate change. In recent decades, the water level of the largest lake in Iran, Urmia Lake, has decreased sharply, which has become a major environmental concern in Iran and the region. The efforts to revive the lake concerns the amount of water required for restoration. This study monitored and assessed Urmia Lake status over a period of 30 years (1984 to 2014) using remotely sensed data. A novel method is proposed that generates a lakebed digital elevation model (LBDEM) for Urmia Lake based on time series images from Landsat satellites, water level field measurements, remote sensing techniques, GIS, and 3D modeling. The volume of water required to restore the Lake water level to that of previous years and the ecological water level was calculated based on LBDEM. The results indicate a marked change in the area and volume of the lake from its maximum water level in 1998 to its minimum level in 2014. During this period, 86% of the lake became a salt desert and the volume of the lake water in 2013 was just 0.83% of the 1998 volume. The volume of water required to restore Urmia Lake from benchmark status (in 2014) to ecological water level (1274.10 m) is 12.546 Bm 3 , excluding evaporation. The results and the proposed method can be used by national and international environmental organizations to monitor and assess the status of Urmia Lake and support them in decision-making.

  15. Ecobiological assessment of a freshwater lake at Schirmacher Oasis, East Antarctica, with reference to human activities

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Dhargalkar, V.K.

    The scale and magnitude of probable impact of human activities over a decade (1983-1994) on the freshwater lake Priyadarshini, at Schirmacher Oasis, East Antarctica, was assessed through an ecological study conducted over an annual cycle during...

  16. Water Resource Inventory and Assessment (WRIA) - Swan Lake National Wildlife Refuge (United States)

    US Fish and Wildlife Service, Department of the Interior — This Water Resource Inventory and Assessment (WRIA) Summary Report for Swan Lake National Wildlife Refuge describes current hydrologic information, provides an...

  17. Environmental Assessment: Sport Hunting Plan for Crescent Lake National Wildlife Refuge (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment (EA) considers four alternatives for expanding hunting on Crescent Lake NWR. The preferred alternative is to expand hunting...

  18. NV - Assessment of wildlife hazards associated with mine pit lakes (United States)

    US Fish and Wildlife Service, Department of the Interior — Several open pit mines in Nevada lower groundwater to mine ore below the water table. After mining, the pits partially fill with groundwater to form pit lakes. Water...

  19. Hydroacoustic assessment of resident species in the Ugashik Lakes, Alaska (United States)

    US Fish and Wildlife Service, Department of the Interior — The Ugashik Lakes in southwest Alaska are a large, remote, thereimictic system that does not thermally stratify during the ice-free season. Little research has been...

  20. The interaction of large amplitude internal seiches with a shallow sloping lakebed: observations of benthic turbulence in Lake Simcoe, Ontario, Canada.

    Directory of Open Access Journals (Sweden)

    Remo Cossu

    Full Text Available Observations of the interactions of large amplitude internal seiches with the sloping boundary of Lake Simcoe, Canada show a pronounced asymmetry between up- and downwelling. Data were obtained during a 42-day period in late summer with an ADCP and an array of four thermistor chains located in a 5 km line at the depths where the thermocline intersects the shallow slope of the lakebed. The thermocline is located at depths of 12-14 m during the strongly stratified period of late summer. During periods of strong westerly winds the thermocline is deflected as much as 8 m vertically and interacts directly with the lakebed at depth between 14-18 m. When the thermocline was rising at the boundary, the stratification resembles a turbulent bore that propagates up the sloping lakebed with a speed of 0.05-0.15 m s(-1 and a Froude number close to unity. There were strong temperature overturns associated with the abrupt changes in temperature across the bore. Based on the size of overturns in the near bed stratification, we show that the inferred turbulent diffusivity varies by up to two orders of magnitude between up- and downwellings. When the thermocline was rising, estimates of turbulent diffusivity were high with KZ ∼10(-4 m(2s(-1, whereas during downwelling events the near-bed stratification was greatly increased and the turbulence was reduced. This asymmetry is consistent with previous field observations and underlines the importance of shear-induced convection in benthic bottom boundary layers of stratified lakes.

  1. Trophic state assessment of Bhindawas Lake, Haryana, India. (United States)

    Saluja, Ridhi; Garg, J K


    Trophic state allows for identification of problems and pressures that an ecosystem faces as well as demarcation of remedial measures. This study focuses on spatial and temporal variations in the trophic state and detection of possible causes of its divergence in Bhindawas Lake, India. The trophic state of the lake undulated between eutrophic and hyper-eutrophic state throughout the study period. Higher phosphorus concentration within the lake ecosystem is the dominant causal factor for its eutrophic state. The influence of other water quality parameters has also been analyzed using Spearman's coefficient of correlation. Deviations between trophic state index (TSI)-chlorophyll-a (Chl-a), TSI-total phosphorus (TP), and TSI-Secchi depth (SD) pointed out that the lake is principally phosphorus limited, and its trophic status is influenced by non-algal turbidity to a large extent. Spatial analysis of trophic levels in geographic information system (GIS) helped in identification of pollution sources and chemical attributes affecting the trophic state of the lake. This study provides a rationale for further investigation of nutrient and sediment loading into the lake system and development of sustainable management and conservation strategy identifying suitable measures ascertaining the ecosystem integrity.

  2. Assessing lake eutrophication using chironomids: understanding the nature of community response in different lake types

    DEFF Research Database (Denmark)

    Langdon, P. G.; Ruiz, Z.; Brodersen, K. P.


    1. Total phosphorus (TP) and chlorophyll a (Chl a) chironomid inference models ( Brodersen & Lindegaard, 1999 ; Brooks, Bennion & Birks, 2001 ) were used in an attempt to reconstruct changes in nutrients from three very different lake types. Both training sets were expanded, particularly at the l...

  3. Remote sensing approach for hydrologic assessments of complex lake systems (United States)

    Bhang, Kon Joon

    Lake studies play an important role in understanding water management, ecology, climatology, etc. because most of earth processes are strongly related to water dynamics. Because the studies have only used on-site gage readings, it is almost impossible to access individual lakes and to evaluate regional scale hydrology as a whole system. Especially in the Prairie Pothole Region (PPR) of North America has millions of potholes and lakes. Measuring lake levels in this region is one of the critical issues in hydrology or other related sciences and applications. The remote sensing approach with the Geographic Information System (GIS) technique could be used to overcome the difficulty associated with on-site measurements. In this study, the SRTM data was used as a main topographic dataset because the dataset provides accurate and consistent elevation data on a worldwide basis. The first chapter introduced the whole idea of this study. In the second chapter, the elevation values of the C-band SRTM 30-meter DEM were compared with point-wise elevations from the Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry for Otter Tail County, MN. The accuracy of SRTM DEM was measured as a function of land cover and geomorphologic characteristics. The typical mean vertical difference between the SRTM DEM and ICESat elevations in this study was determined for each classified land use type and the data properties were investigated. Also, the feasibility of using SRTM data for hydrologic applications, especially in a region of low relief exemplified by the Otter Tail basin in Minnesota, was examined in Chapter 3. For measuring lake levels, several lake-level estimation techniques using image processing and feature detection were tested with the Landsat imagery and SRTM data and the efficiency of the techniques were evaluated in Chapter 4. Lastly, the power law distribution of lake was simulated in Chapter 5. For the simulation, one-dimensional fractal landscapes were

  4. Distribution of lake sturgeon in New York: 11 years of restoration management (United States)

    Chalupnicki, M.A.; Dittman, D.E.; Carlson, D.M.


    Lake sturgeon (Acipenser fulvescens) are native within the Lake Ontario drainage basin and listed as threatened by New York State. In 1995 the New York State Department of Environmental Conservation (NYSDEC) initiated restoration management of lake sturgeon. This management included both protection of extant populations and stocking of uninhabited historic waters with juvenile sturgeon. A list compiled by NYSDEC of observations of lake sturgeon from New York State waters for the period encompassing 1800-2005 was combined with recent observations through 2008 and formatted (Geographic Information System) to allow mapping of sturgeon geographical distribution. Distributions of pre- and post-restoration sturgeon were examined by occurrence and type of observation. Distribution patterns indicated lakes and rivers with current sturgeon presence have increased from five to eight, which was the first-phase goal of the New York Lake Sturgeon Recovery Plan. Lake sturgeon have started to expand into joining water to include the Indian R., Oneida R., Seneca R. and Oswego R. The protected historic populations in the Niagara R., Grasse R., St. Lawrence R., and Lakes Erie and Ontario continue to have low numbers of sturgeon observations. This summary of mapped lake sturgeon distribution information will help in guiding research assessments to waters containing substantial populations. These accessible reaches provide a generous advantage to the released juveniles as they move toward the next goal of restoration, spawning of sturgeon in targeted waters. ?? 2011 American Midland Naturalist.

  5. Cyanotoxins in Inland Lakes of the United States: Occurrence and Potential Recreational Health Risks in the EPA National Lakes Assessment 2007 (United States)

    A large nation-wide survey or cyanotoxlns (1161 lakes)in the United States (U.S.) was conducted dunng the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse to...

  6. Artificial reefs and reef restoration in the Laurentian Great Lakes (United States)

    McLean, Matthew W.; Roseman, Edward; Pritt, Jeremy J.; Kennedy, Gregory W.; Manny, Bruce A.


    We reviewed the published literature to provide an inventory of Laurentian Great Lakes artificial reef projects and their purposes. We also sought to characterize physical and biological monitoring for artificial reef projects in the Great Lakes and determine the success of artificial reefs in meeting project objectives. We found records of 6 artificial reefs in Lake Erie, 8 in Lake Michigan, 3 in Lakes Huron and Ontario, and 2 in Lake Superior. We found 9 reefs in Great Lakes connecting channels and 6 reefs in Great Lakes tributaries. Objectives of artificial reef creation have included reducing impacts of currents and waves, providing safe harbors, improving sport-fishing opportunities, and enhancing/restoring fish spawning habitats. Most reefs in the lakes themselves were incidental (not created purposely for fish habitat) or built to improve local sport fishing, whereas reefs in tributaries and connecting channels were more frequently built to benefit fish spawning. Levels of assessment of reef performance varied; but long-term monitoring was uncommon as was assessment of physical attributes. Artificial reefs were often successful at attracting recreational species and spawning fish; however, population-level benefits of artificial reefs are unclear. Stressors such as sedimentation and bio-fouling can limit the effectiveness of artificial reefs as spawning enhancement tools. Our investigation underscores the need to develop standard protocols for monitoring the biological and physical attributes of artificial structures. Further, long-term monitoring is needed to assess the benefits of artificial reefs to fish populations and inform future artificial reef projects.

  7. Development of FVSOntario: A Forest Vegetation Simulator Variant and application software for Ontario (United States)

    Murray E. Woods; Donald C. E. Robinson


    The Ontario Ministry of Natural Resources is leading a government-industry partnership to develop an Ontario variant of the Forest Vegetation Simulator (FVS). Based on the Lake States variant and the PrognosisBC user-interface, the FVSOntarioproject is motivated by a need to model the impacts of intensive forest management...

  8. Assessing Holocene water level changes of Lake Turkana, Kenya with potential linkages to monsoon variability (United States)

    Bloszies, C.; Forman, S. L.; Wright, D. K.


    This study focuses on better defining water level variability in the past 10 ka for Lake Turkana, Kenya. The water level of Lake Turkana was approximately 90m higher than today ca. 8 ka years ago, and in the past century lake levels have varied by up to 15 m. Lake level is especially sensitive to shifts in water balance with changes in regional rainfall linked to the relative strength of the Indian Ocean Monsoon. Variations in monsoonal precipitation in Kenya may be controlled by distinct modes of the Indian Ocean Dipole, with one mode associated with increased sea surface temperatures and concomitant heavy rainfall in the Turkana basin, and the other mode resulting in low precipitation. Well preserved beach ridges up to 90 m above present water level occur around the lake representing a record of varying elevations of lake level still-stands during the Holocene. Along this prograded strand plain there is evidence of a shift in human subsistence from fishing villages to pastoral encampments, possibly associated with pronounced mid-Holocene drying and a precipitous (>30 m) fall in lake level ca. between 7 and 5 ka. However, a recent GPS campaign of beach ridges on the east and west sides of the lake reveal variability in highstand beach ridge elevations, implying deferential tectonic deformation across the basin and possible crustal warping due to hydroisostatic processes. Radiocarbon dating of aquatic shells will resolve the ages of beach ridges and these ages will be tested by direct dating of littoral quartz grains by OSL. Stratigraphic exposures of this littoral system reveal new evidence for lake still-stands, transgressions and regressions. Ultimately, the data will constrain a basin hydrologic model to assess the catchment changes and evaporative conditions required to yield the tens of meters of lake level change in the Holocene and provide new insights into the magnitude and linkage to monsoon variability.

  9. Assessment of water quality in Ahor Lake - Ghana

    African Journals Online (AJOL)


    water demand during dry seasons. After the collapse of. Ghana Consolidated Diamonds which took over operations from the CAST mining company, the Dam has been abandoned. Recently, the Municipal has taken interest in the water body to develop it for recreational purpose. Climatically, Lake Ahor lies within the Wet ...

  10. Assessing Lake Trophic Status: A Proportional Odds Logistic Regression Model (United States)

    Lake trophic state classifications are good predictors of ecosystem condition and are indicative of both ecosystem services (e.g., recreation and aesthetics), and disservices (e.g., harmful algal blooms). Methods for classifying trophic state are based off the foundational work o...

  11. Great Lakes Nearshore Assessment: What Would Goldilocks Do? (United States)

    Concerns with the nearshore water quality of the Great Lakes, such as excessive eutrophication and harmful algal blooms, called for establishing a nearshore monitoring program to gain a better understanding of the watershed-nearshore link. This is challenging, as sporadic runoff ...

  12. Ecological risk assessment of Grass Carp (Ctenopharyngodon idella) for the Great Lakes Basin (United States)

    Kolar, Cynthia S.; Cudmore, Becky


    Grass Carp (Ctenopharyngodon idella) is an herbivorous, freshwater fish that was first introduced in the United States in the early 1960s for use in biological control of aquatic vegetation. It has since escaped and dispersed through the Mississippi River basin towards the Great Lakes. To characterize the risk of Grass Carp to the Great Lakes basin, a binational ecological risk assessment of Grass Carp was conducted.This risk assessment covered both triploid (sterile) and diploid (fertile) Grass Carp and assessed the likelihood of arrival, survival, establishment, and spread, and the magnitude of the ecological consequences within 5, 10, 20 and 50 years from 2014 (i.e., the baseline year) to the connected Great Lakes basin (defined as the Great Lakes basin and its tributaries to the first impassable barrier; risk was assessed based on current climate conditions and at the individual lake scale but does not address a finer geographical scale (e.g., bay or sub-region).For triploid Grass Carp, the probability of occurrence (likelihood of arrival, survival, and spread) was assessed, and for diploid Grass Carp the probability of introduction (likelihood of arrival, survival, establishment and spread) was assessed.

  13. Quantitative assessment of glacial fluctuations in the level of Lake Lisan, Dead Sea rift (United States)

    Rohling, Eelco J.


    A quantitative understanding of climatic variations in the Levant during the last glacial cycle is needed to support archaeologists in assessing the drivers behind hominin migrations and cultural developments in this key region at the intersection between Africa and Europe. It will also foster a better understanding of the region's natural variability as context to projections of modern climate change. Detailed documentation of variations in the level of Lake Lisan - the lake that occupied the Dead Sea rift during the last glacial cycle - provides crucial climatic information for this region. Existing reconstructions suggest that Lake Lisan highstands during cold intervals of the last glacial cycle represent relatively humid conditions in the region, but these interpretations have remained predominantly qualitative. Here, I evaluate realistic ranges of the key climatological parameters that controlled lake level, based on the observed timing and amplitudes of lake-level variability. I infer that a mean precipitation rate over the wider catchment area of about 500 mm y-1, as proposed in the literature, would be consistent with observed lake levels if there was a concomitant 15-50% increase in wind speed during cold glacial stadials. This lends quantitative support to previous inferences of a notable increase in the intensity of Mediterranean (winter) storms during glacial periods, which tracked eastward into the Levant. In contrast to highstands during ‘regular’ stadials, lake level dropped during Heinrich Events. I demonstrate that this likely indicates a further intensification of the winds during those times.

  14. Feasibility of Small Wind Turbines in Ontario: Integrating Power Curves with Wind Trends

    Directory of Open Access Journals (Sweden)

    Masaō Ashtine


    Full Text Available Micro-scale/small wind turbines, unlike larger utility-scale turbines, produce electricity at a rate of 300 W to 10 kW at their rated wind speed and are typically below 30 m in hub-height. These wind turbines have much more flexibility in their costs, maintenance and siting, owing to their size, and can provided wind energy in areas much less suited for direct supply to the grid system. In the future under climate change, the energy landscape will likely shift from the present centralized electricity generation and delivery system to a more distributed and locally-generated electricity and delivery system. In the new system configuration, the role of relatively small sustainable electricity generators like small wind turbines will likely become more prominent. However, the small wind industry has been substantially slow to progress in Ontario, Canada, and there is much debate over its viability in a growing energy dependent economy. This study seeks to demonstrate the performance of a small wind turbine, and speculate on its potential power output and trend over Ontario historically over the last 33 years using the North American Regional Reanalysis (NARR data. We assessed the efficiency of a Bergey Excel 1 kW wind turbine at the pre-established Kortright Centre for Conservation test site, located north of Toronto. Using a novel approach, the Bergey optimized power curve was incorporated with reanalysis data to establish power output across Ontario at three-hour resolution. Small turbine-based wind power around the Great Lakes and eastern James Bay increased during winter and fall, contributing up to 10% of the annual electricity demand in some regions in Ontario. We purport that increases in power output are driven by long-term reductions in sea and lake ice concentrations affecting atmospheric stability in surrounding regions.

  15. Lake breezes in the southern Great Lakes region and their influence during BAQS-Met 2007

    Directory of Open Access Journals (Sweden)

    D. M. L. Sills


    Full Text Available Meteorological observations from the BAQS-Met field experiment during the summer months of 2007 were integrated and manually analyzed in order to identify and characterize lake breezes in the southern Great Lakes region of North America, and assess their potential impact on air quality. Lake breezes occurred frequently, with one or more lake breezes identified on 90 % of study days. They affected all parts of the study region, including southwestern Ontario and nearby portions of southeast Lower Michigan and northern Ohio, with lake-breeze fronts occasionally penetrating from 100 km to over 200 km inland. Occurrence rates and penetration distances were found to be higher than previously reported in the literature. This comprehensive depiction of observed lake breezes allows an improved understanding of their influence on the transport, dispersion, and production of pollutants in this region.

    The observational analyses were compared with output from subsequent runs of a high-resolution numerical weather prediction model. The model accurately predicted lake breeze occurrence and type in a variety of synoptic wind regimes, but selected cases showed substantial differences in the detailed timing and location of lake-breeze fronts, and with the initiation of deep moist convection. Knowledge of such strengths and weaknesses aids in the interpretation of results from air quality models driven by this meteorological model.

  16. Compliance with school nutrition policies in Ontario and Alberta: An assessment of secondary school vending machine data from the COMPASS study. (United States)

    Vine, Michelle M; Harrington, Daniel W; Butler, Alexandra; Patte, Karen; Godin, Katelyn; Leatherdale, Scott T


    We investigated the extent to which a sample of Ontario and Alberta secondary schools are being compliant with their respective provincial nutrition policies, in terms of the food and beverages sold in vending machines. This observational study used objective data on drinks and snacks from vending machines, collected over three years of the COMPASS study (2012/2013-2014/2015 school years). Drink (e.g., sugar-containing carbonated/non-carbonated soft drinks, sports drinks, etc.) and snack (e.g., chips, crackers, etc.) data were coded by number of units available, price, and location of vending machine(s) in the school. Univariate and bivariate analyses were undertaken using R version 3.2.3. In order to assess policy compliancy over time, nutritional information of products in vending machines was compared to nutrition standards set out in P/PM 150 in Ontario, and those set out in the Alberta Nutrition Guidelines for Children and Youth (2012) in Alberta. Results reveal a decline over time in the proportion of schools selling sugar-containing carbonated soft drinks (9% in 2012/2013 vs. 3% in 2014/2015), crackers (26% vs. 17%) and cake products (12% vs. 5%) in vending machines, and inconsistent changes in the proportion selling chips (53%, 67% and 65% over the three school years). Conversely, results highlight increases in the proportion of vending machines selling chocolate bars (7% vs. 13%) and cookies (21% vs. 40%) between the 2012/2013 and 2014/2015 school years. Nutritional standard policies were not adhered to in the majority of schools with respect to vending machines. There is a need for investment in formal monitoring and evaluation of school policies, and the provision of information and tools to support nutrition policy implementation.

  17. Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record

    Directory of Open Access Journals (Sweden)

    Helen eBennion


    Full Text Available Efforts to restore enriched lakes have increased yet there remains uncertainty about whether restoration targets can be achieved and over what timescale. Paleoecological techniques, principally diatom analyses, were used to examine the degree of impact and recovery in 12 European lakes subject to eutrophication and subsequent reduction in nutrient loading. Dissimilarity scores showed that all sites experienced progressive deviation from the reference sample (core bottom prior to nutrient reduction, and principal curves indicated gradual compositional change with enrichment. When additive models were applied to the latter, the changes were statistically significant in 9 of the 12 sites. Shifts in diatom composition following reduction in nutrient loading were more equivocal, with a reversal towards the reference flora seen only in four of the deep lakes and one of the shallow lakes. Of these, only two were significant (Lake Bled and Mjøsa. Alternative nutrient sources seem to explain the lack of apparent recovery in the other deep lakes. In three shallow lakes diatom assemblages were replaced by a community associated with lower productivity but not the one seen prior to enrichment. Internal loading and top down control may influence recovery in shallow lakes and climate change may have confounded recovery in several of the study sites. Hence, ecosystem recovery is not simply a reversal of the degradation pathway and may take several decades to complete or, for some lakes, may not take place at all. By assessing ecological change over a decadal to centennial timescale, the study highlights the important role that paleolimnology can play in establishing a benchmark against which managers can evaluate the degree to which their restoration efforts are successful.

  18. Environmental Assessment of remedial action at the Ambrosia Lake uranium mill tailings site, Ambrosia Lake, New Mexico

    Energy Technology Data Exchange (ETDEWEB)


    This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico. The designated site covers 196 acres and contains 111 acres of tailings and some of the original mill structures. The Uranium Mill Tailings Radiation Control Act (UMTRCA), Public Law 95-604, authorizes the US Department of Energy to clean up the site to reduce the potential health impacts associated with the residual radioactive materials remaining at the site and at associated properties off the site. The US Environmental Protection Agency promulgated standards for th remedial action (40 CFR Part 192). Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile. Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document.

  19. Direct heat applications of geothermal energy in The Geysers/Clear Lake region. Volume I. Geotechnical assessment, agribusiness applications, socioeconomic assessment, engineering assessment. Final report

    Energy Technology Data Exchange (ETDEWEB)


    Discussion is presented under the following section headings: background and some technical characteristics of geothermal resources; geology and geohydrology, geophysics, and, conclusions regarding availability of geothermal energy for nonelectric uses; agricultural assessment of Lake County, site assessment for potential agricultural development, analysis of potential agricultural applications, special application of low cost geothermal energy to algae harvesting, development of an integrated agribusiness, geothermal complex in Lake County, analysis of individual enterprises, and, recommendations for subsequent work; demographic characteristics, economic condition and perspective of Lake County, economic impact of geothermal in Lake County, social and economic factors related to geothermal resource development, socioeconomic impact of nonelectric uses of geothermal energy, and, identification of direct heat applications of geothermal energy for Lake County based on selected interviews; cost estimate procedure, example, justification of procedure, and, typical costs and conclusions; and, recommended prefeasibility and feasibility studies related to construction of facilities for nonelectric applications of geothermal resource utilization. (JGB)

  20. Lake Diefenbaker: Water Quality Assessment and Modeling for Management under Environmental Change (United States)

    Sereda, J.; Wheater, H. S.; Hudson, J.; Doig, L.; Liber, K.; Jones, P.; Giesy, J.; Bharadwaj, L.


    Preliminary results are presented for a comprehensive inter-disciplinary study on Lake Diefenbaker initiated by the Global Institute for Water Security to understand the physical and biogeochemical processes affecting water quality under climate change and their policy implications. Lake Diefenbaker is a large reservoir (surface area ~500km2 and Zmean ~33m) located in Southern Saskatchewan, Canada and is a critically-important water resource for Saskatchewan. It receives nearly all of its flow from the South Saskatchewan River, which flows through some of the most urbanized and intense agricultural lands of southern Alberta. As a result these waters contain high levels of nutrients [nitrogen (N) and phosphorus (P)] along with a variety of chemical contaminants characteristic of anthropogenic activity. In addition, riparian and in-lake activities provide local sources of nutrients, from domestic sewage, agriculture and fish farming. The South Saskatchewan River has been identified by the World Wildlife Fund (2009) as Canada's most threatened river in terms of environmental flow. Lake Diefenbaker has numerous large deep embayments (depth >20m) and an annual water level fluctuation of ~6m. A deep thermocline (~25m) forms infrequently. Stratification does not occur throughout the lake. Anecdotal information suggests that the frequency and severity of algal blooms are increasing; although blooms have been sporadic and localized. This localized eutrophication may be related to local stratification patterns, point source nutrient loading, and/or internal lake processes (i.e., internal nutrient loading). A paleolimnological reconstruction has begun to assess historical nutrient and contaminant loading to Lake Diefenbaker and hence the trajectory of water quality in the lake. Major point sources and diffuse sources of N and P are also under investigation. In addition, the type (N versus P) and degree of nutrient limitation of bacteria and algae are being assessed (spatially

  1. Development of a methodological tool for the assessment of the hydromorphological conditions of lakes in Europe (United States)

    Gay, Aurore; Argillier, Christine; Reynaud, Nathalie; Nicolas, Delphine; Baudoin, Jean-Marc


    The assessment of the ecological status of surface waters considering the biological, physico-chemical and hydromorphological conditions is requested by the European Water Framework Directive (WFD). If research efforts have particularly concentrated on rivers, lakes have yet received less attention. Nevertheless, due to their function of receptacles of inland waters, the habitats they provide to an important biodiversity and the numerous services they support (water supply, recreational activities, hydroelectricity), assessing the ecological quality of lakes becomes crucial for their protection. Still, this task remains challenging, especially considering the hydromorphological compartments. Indeed, while promising tools already exist to assess the lake biological and physico-chemical status, our comprehension of the impact of hydromophological impairments on the global ecosystem functioning remains poor and existing tools to assess such impacts often focus only on morphological aspects and in a qualitative rather than quantitative way. In this context, our study aims at providing stakeholders with a methodology to assess quantitatively the hydrological and morphological quality of lakes in Europe. The developed methodology, LAKe HYdromorphological Conditions tool (LAKHYC tool) is based on our current knowledge of the functioning of lakes and pre-existing works (e.g., Rowan et al., 2012; Rinaldi et al., 2013). The LAKHYC tool integrates the six parameters requested by the WFD, each one being assessed by at least three descriptors that are calculated as Ecological Quality Ratios, i.e. as the deviation from a reference condition. The originality of the present method lies in the fact that specific reference conditions are defined for each descriptor. In this way, we avoid using a predetermined set of lakes considered as not impacted by human activities and which often corresponds to natural lakes in specific areas (e.g., mountains) and do not represent the diversity

  2. Spatial distribution and pollution assessment of mercury in sediments of Lake Taihu, China. (United States)

    Chen, Chunxiao; Zheng, Binghui; Jiang, Xia; Zhao, Zheng; Zhan, Yuzhu; Yi, Fengjiao; Ren, Jiaying


    Spatial distribution patterns of total mercury (THg) in 36 surficial sediment samples representing five regions of Lake Taihu were assessed using the ArcGis geostatistical analyst module. The pollution levels of THg were also evaluated from the same five lake regions. Concentrations of THg were in a ranged of 23-168 ng/g (mean 55 ng/g) in surfical sediments, which was significantly higher than those established baseline levels of the lake. Results of THg indicated that the northern region exhibited notably higher values, the bay regions showed elevated values relative to open areas, and the lakeside regions were higher than those observed in the central area. Lake Taihu suffered moderate to high Hg pollution, and expressed clear Hg enrichment status according to monomial pollution index I(geo) and human activity factors. The concentrations of THg in the surficial sediments of Lake Taihu showed moderate-strong variation (coefficient of variation 52%). Geostatistical analysis indicated a weak spatial self-correlation, suggesting the contamination of Hg in Lake Taihu is primarily the result of anthropogenic activities.

  3. Geochemical speciation and pollution assessment of heavy metals in surface sediments from Nansi Lake, China. (United States)

    Yang, Liyuan; Wang, Longfeng; Wang, Yunqian; Zhang, Wei


    Sixteen surface sediment samples were collected from Nansi Lake to analyze geochemical speciation of heavy metals including Cd, As, Pb, Cr, and Zn, assess their pollution level, and determine the spatial distribution of the non-residual fraction. Results showed that Cd had higher concentrations in water-soluble and exchangeable fractions. As and Pb were mainly observed as humic acid and reducible fractions among the non-residual fractions, while Cr and Zn were mostly locked up in a residual fraction. The mean pollution index (P i) values revealed that the lower lake generally had a higher enrichment degree than the upper lake. Cd (2.73) and As (2.05) were in moderate level of pollution, while the pollution of Pb (1.80), Cr (1.27), and Zn (1.02) appeared at low-level pollution. The calculated pollution load index (PLI) suggested the upper lake suffered from borderline moderate pollution, while the lower lake showed moderate to heavy pollution. Spatial principle component analysis showed that the first principal component (PC1) including Cd, As, and Pb could explain 56.18 % of the non-residual fraction. High values of PC1 were observed mostly in the southern part of Weishan Lake, which indicated greater bioavailability and toxicity of Cd, As, and Pb in this area.

  4. Water quality monitoring and assessment of an urban Mediterranean lake facilitated by remote sensing applications. (United States)

    Markogianni, V; Dimitriou, E; Karaouzas, I


    Degradation of water quality is a major problem worldwide and often leads to serious environmental impacts and concerns about public health. In this study, the water quality monitoring and assessment of the Koumoundourou Lake, a brackish urban shallow lake located in the northeastern part of Elefsis Bay (Greece), were evaluated. A number of water quality parameters (pH, temperature, dissolved oxygen concentration, electrical conductivity, turbidity, nutrients, and chlorophyll-a concentration) were analyzed in water samples collected bimonthly over a 1-year period from five stations throughout the lake. Moreover, biological quality elements were analysed seasonally over the 1-year period (benthic fauna). Statistical analysis was performed in order to evaluate the water quality of the lake and distinguish sources of variation measured in the samples. Furthermore, the chemical and trophic status of the lake was evaluated according to the most widely applicable classification schemes. Satellite images of Landsat 5 Thematic Mapper were used in order for algorithms to be developed and calculate the concentration of chlorophyll-a (Chl-a). The trophic status of the lake was characterized as oligotrophic based on phosphorus and as mesotrophic-eutrophic based on Chl-a concentrations. The results of the remote sensing application indicated a relatively high coefficient of determination (R (2)) among point sampling results and the remotely sensed data, which implies that the selected algorithm is reliable and could be used for the monitoring of Chl-a concentration in the particular water body when no field data are available.

  5. Detecting river sediments to assess hazardous materials at volcanic lake using advanced remote sensing techniques (United States)

    Saepuloh, Asep; Fitrianingtyas, Chintya


    The Toba Caldera formed from large depression of Quaternary volcanism is a remarkable feature at the Earth surface. The last Toba super eruptions were recorded around 73 ka and produced the Youngest Toba Tuff about 2,800 km3. Since then, there is no record of significant volcanic seismicity at Toba Volcanic Complex (TVC). However, the hydrothermal activities are still on going as presented by the existence of hot springs and alteration zones at the northwest caldera. The hydrothermal fluids probably containing some chemical compositions mixed with surficial water pollutant and contaminated the Toba Lake. Therefore, an environmental issues related to the existence of chemical composition and degradation of water clearness in the lake had been raised in the local community. The pollutant sources are debatable between natural and anthropogenic influences because some human activities grow rapidly at and around the lake such as hotels, tourisms, husbandry, aquaculture, as well as urbanization. Therefore, obtaining correct information about the source materials floating at the surface of the Toba Lake is crucial for environmental and hazard mitigation purposes. Overcoming the problem, we presented this paper to assess the source possibility of floating materials at Toba Lake, especially from natural sources such as hydrothermal activities of TVC and river stream sediments. The Spectral Angle Mapper (SAM) techniques using atmospherically corrected of Landsat-8 and colour composite of Polarimetric Synthetic Aperture Radar (PolSAR) were used to map the distribution of floating materials. The seven ground truth points were used to confirm the correctness of proposed method. Based on the SAM and PolSAR techniques, we could detect the interface of hydrothermal fluid at the lake surfaces. Various distributions of stream sediment were also detected from the river mouth to the lake. The influence possibilities of the upwelling process from the bottom floor of Toba Lake were also

  6. Aquatic assessment in the Lake Tumba landscape, DRCongo


    Mputu, Adèle


    The 80,000 km² Lake Tumba Landscape (LTL) is the only one of the 12 UN Priority Conservation Areas in Africa with a focus on freshwater ecosystems. Surprisingly little though is known about fish in this area. The objective of this thesis is to increase knowledge of fish occurrence in the LTL. The first paper uses catch statistics to quantify the fish populations in three LTL streams against the background of their physical and chemical environments (Paper I). All the specie...

  7. Spatial variation in lake benthic macroinvertebrate ecological assessment: a synthesis of European case studies

    DEFF Research Database (Denmark)

    Sandin, Leif Leonard; Solimini, Angelo G.


    local invertebrate assemblages. In this issue we provide a contribution towards the understanding of basic sources of spatial variation of invertebrate assemblages in different European lake habitat types and their relationship with major human pressures. All papers have an obvious applied objective...... Baltic, Atlantic, and Mediterranean). The goal of the papers was to assess the main environmental factors and how they affected benthic macroinvertebrate variation at different ecological scales and thus better our basic understanding of how changes in these environmental variables can be tracked using......This paper summarizes eight case studies that were analysed as part of the research theme ``lake benthic macroinvertebrates'' forming part of the EU-funded WISER project ``Water bodies in Europe: Integrative Systems to assess Ecological status and Recovery''. The relationships between lake benthic...

  8. Lakes as a Source of Short-Period (0.5-2 s) Microseisms (United States)

    Xu, Yan; Koper, Keith D.; Burlacu, Relu


    We identify and document microseisms produced by wave action in six lakes: The Great Slave Lake, Lake Ontario, Yellowstone Lake, Dianchi Lake, Fuxian Lake, and Erhai Lake. The lakes span more than 2 orders of magnitude in size (areas of 210-27,000 km2) and sample a range of climatic and tectonic regimes in Canada, the U.S., and China. Lake-generated microseisms create spectral peaks at periods near 1 s and are often polarized as Rayleigh waves propagating away from the lake. In contrast to ocean-generated microseisms, lake-generated microseisms are only observed within about 25-30 km of the shoreline. This is consistent with the well-known high attenuation of short-period Rayleigh waves (Rg). It is unclear if lake-generated microseisms are produced by a linear shoaling process, analogous to primary ocean microseisms, or a nonlinear wave-wave interaction process, analogous to secondary ocean microseisms. If they are mainly produced by shoaling, lake-generated microseisms might provide a spatially integrated measure of shoreline erosion. Regardless of the source mechanism, lake-generated microseisms appear to provide a record of ice phenology for lakes that freeze in the winter. Such data could contribute to assessing the effects of climate change on high-latitude lakes in remote areas. Finally, it is likely that lake-generated microseisms are useful for imaging the geological structure of the shallow crust, information that is important for quantifying seismic hazard and can be difficult to obtain in urban areas where active source imaging is not feasible.

  9. Community-scale assessment of rooftop-mounted solar energy potential with meteorological, atlas, and GIS data: a case study of Guelph, Ontario (Canada)

    National Research Council Canada - National Science Library

    McIntyre, Joseph H


    Forward-thinking governments recognize that local renewable resource use is crucial to the resilience of communities and are developing and implementing community energy plans (CEPs). Guelph, Ontario, (Canada...

  10. Investigating the Homogeneity and Distinguishability of STEP Proficiency Descriptors in Assessing English Language Learners in Ontario Schools (United States)

    Jang, Eunice Eunhee; Cummins, Jim; Wagner, Maryam; Stille, Saskia; Dunlop, Maggie


    Research on issues concerning the assessment of school-age English language learners (ELLs) in curriculum-learning contexts has been relatively less productive than assessment of adult language learners. A growing demand for assessing school-age ELLs has led to the development of assessment frameworks that provide the opportunity to examine the…

  11. Aquatic environmental assessment of Lake Balaton in the light of physical-chemical water parameters. (United States)

    Sebestyén, Vitkor; Németh, József; Juzsakova, Tatjana; Domokos, Endre; Kovács, Zsófia; Rédey, Ákos


    One of the issues of the Hungarian Water Management Strategy is the improvement and upgrading of the water of Lake Balaton. The Water Framework Directive (WFD) specifies and sets forth the achievement of the good ecological status. However, the assessment of the water quality of the lake as a complex system requires a comprehensive monitoring and evaluation procedure. Measurements were carried out around the Lake Balaton at ten different locations/sites and 13 physical-chemical parameters were monitored at each measurement site.For the interpretation of the water chemistry parameters the Aquatic Environmental Assessment (AEA) method devised by authors was used for the water body of the Lake Balaton. The AEA method can be used for all types of the water bodies since it is flexible and using individual weighting procedure for the water chemistry parameters comprehensive information can be obtain. The AEA method was compared with existing EIA methods according to a predefined criterion system and proved to be the most suitable tool for evaluating the environmental impacts in our study.On the basis of the results it can be concluded that the status of the quality of studied area on the Lake Balaton can be categorized as proper quality (from the outcome of the ten measurement sites this conclusion was reached at seven sites).

  12. ERTS computer compatible tape data processing and analysis. Appendix 1: The utility of imaging radars for the study of lake ice (United States)

    Polcyn, F. C.; Thomson, F. J.; Porcello, L. J.; Sattinger, I. J.; Malila, W. A.; Wezernak, C. T.; Horvath, R.; Vincent, R. K. (Principal Investigator); Bryan, M. L.


    There are no author-identified significant results in this report. Remotely sensed multispectral scanner and return beam vidicon imagery from ERTS-1 is being used for: (1) water depth measurements in the Virgin Islands and Upper Lake Michigan areas; (2) mapping of the Yellowstone National Park; (3) assessment of atmospheric effects in Colorado; (4) lake ice surveillance in Canada and Great Lakes areas; (5) recreational land use in Southeast Michigan; (6) International Field Year on the Great Lakes investigations of Lake Ontario; (7) image enhancement of multispectral scanner data using existing techniques; (8) water quality monitoring of the New York Bight, Tampa Bay, Lake Michigan, Santa Barbara Channel, and Lake Erie; (9) oil pollution detection in the Chesapeake Bay, Gulf of Mexico southwest of New Orleans, and Santa Barbara Channel; and (10) mapping iron compounds in the Wind River Mountains.

  13. Assessing heat fluxes and water quality trends in subalpine lakes from EO (United States)

    Cazzaniga, Ilaria; Giardino, Claudia; Bresciani, Mariano; Elli, Chiara; Valerio, Giulia; Pilotti, Marco


    ones. The atmospherically corrected L8 data were then processed through a site-specific parameterised bio-optical model for water constituents' concentration retrieval. The EO products thus obtained were then analysed as follows. 1) Statistical analyses of water reflectance, a new Essential Climate Variables within the ESA CCI+ initiative, and chl-a concentration, a proxy of trophic status, were performed. Both water reflectance and chl-a concentration were obtained from the MERIS 10-years time series and were analyzed to identify spatial patterns, temporal trends and the onset of phytoplankton growth. 2) Combination of field shortwave and longwave radiation data with the one estimated from L8 OLI and TIRS atmospherically corrected imagery, was exploited to assess the heat fluxes and evaporation rates. In both cases, the analysis was supported by field data to highlight the accuracy of measurements obtained from EO technology. A comparative analysis among the lakes is finally presented. In addition, future work aimed at extending the MERIS time series to the new Sentinel-3-OLCI time series (2016-on going) is discussed, in expectation that EO technology will augment information for lake management and geosciences (lake's ecology and climate, in particular).

  14. Glacial lake outburst flood risk assessment using combined approaches of remote sensing, GIS and dam break modelling

    Directory of Open Access Journals (Sweden)

    Arpit Aggarwal


    Full Text Available A great number of glacial lakes have appeared in many mountain regions across the world during the last half-century due to receding of glaciers and global warming. In the present study, glacial lake outburst flood (GLOF risk assessment has been carried out in the Teesta river basin located in the Sikkim state of India. First, the study focuses on accurate mapping of the glaciers and glacial lakes using multispectral satellite images of Landsat and Indian Remote Sensing satellites. For glacier mapping, normalized difference snow index (NDSI image and slope map of the area have been utilized. NDSI approach can identify glaciers covered with clean snow but debris-covered glaciers cannot be mapped using NDSI method alone. For the present study, slope map has been utilized along with the NDSI approach to delineate glaciers manually. Glacial lakes have been mapped by supervised maximum likelihood classification and normalized difference water index followed by manual editing afterwards using Google Earth images. Second, the first proper inventory of glacial lakes for Teesta basin has been compiled containing information of 143 glacial lakes. Third, analysis of these lakes has been carried out for identification of potentially dangerous lakes. Vulnerable lakes have been identified on the basis of parameters like surface area, position with respect to parent glacier, growth since 2009, slope, distance from the outlet of the basin, presence of supraglacial lakes, presence of other lakes in downstream, condition of moraine, condition of the terrain around them, etc. From these criterions, in total, 18 lakes have been identified as potentially dangerous glacial lakes. Out of these 18 lakes, further analysis has been carried out for the identification of the most vulnerable lake. Lake 140 comes out to be the most vulnerable for a GLOF event. Lastly, for this potentially dangerous lake, different dam break parameters have been generated using satellite data

  15. The Legacy of Arsenic Contamination from Giant Mine, Northern Canada: An Assessment of Impacts Based on Lake Water and Lake Sediment Core Analysis (United States)

    Blais, J. M.; Korosi, J.


    The Giant Mine, which operated between 1948 and 2004 and located near the City of Yellowknife (Northwest Territories, Canada), has left a legacy of arsenic, antimony, and mercury contamination extending to the present day. Over 20,000 tonnes of arsenic trioxide dust was released from roaster stack emissions during its first 10 years of operations, leading to a significant contamination of the surrounding landscape. Here we present a summary of impacts by the recent contamination from Giant Mine on the surrounding region. A survey we conducted of 25 lakes of the region in 2010 revealed that most lake water within a 15 km radius of the roaster stack had arsenic concentrations in water > 10 mg/L, the standard for drinking water, with concentrations declining exponentially with increasing distance from the roaster stack. Sediment cores from lakes were collected near the Giant Mine roaster stack and radiometrically dated by 137Cs and excess 210Pb. Arsenic concentrations in these sediments increased by 1700% during the 1950s and 60s, consistent with the history of arsenic releases from roaster emissions. Correspondingly, pelagic diatoms and cladocerans were extirpated from one lake during this period, based on microfossil analysis of lake sediment deposits. Sediment core analysis further showed that this lake ecosystem has not recovered, even ten years after closure of the mine. Likely causes for the lack of recent recovery are explored with the use of sediment toxicity bioassays, using a novel paleo-ecotoxicological approach of using toxicity assessments of radiometrically dated lake sediment horizons.


    A technique to rapidly assess phytoplankton dynamics is being evaluated for its utility in the Great Lakes. Comparison to traditional microscopic techniques and to more recent in-situ FluoroProbe technology will allow us to determine if HPLC pigment analysis can provide unique a...

  17. Assessing the Accuracy of MODIS-NDVI Derived Land-Cover Across the Great Lakes Basin (United States)

    This research describes the accuracy assessment process for a land-cover dataset developed for the Great Lakes Basin (GLB). This land-cover dataset was developed from the 2007 MODIS Normalized Difference Vegetation Index (NDVI) 16-day composite (MOD13Q) 250 m time-series data. Tr...

  18. Ecological assessment of Great Lota Lake (Turkey) on the base of ...

    African Journals Online (AJOL)


    Ecological assessment of Great Lota Lake (Turkey) on the base of diatom communities. Rıdvan Erdal Sivaci1, Sophia Barinova2, Cüneyt Nadir Solak3 and Kadir Çobanoglu4. 1Department of Biology, Art and Science Faculty, Adiyaman University, Adiyaman 02000, Turkey. 2The Laboratory of Biodiversity and Ecology, the ...

  19. Sanctuaries for lake trout in the Great Lakes (United States)

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


    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. Monitoring and assessment of a eutrophicated coastal lake using multivariate approaches

    Directory of Open Access Journals (Sweden)

    U.G. Abhjna


    Full Text Available Multivariate statistical techniques such as cluster analysis, multidimensional scaling and principal component analysis were applied to evaluate the temporal and spatial variations in water quality data set generated for two years (2008-2010 from six monitoring stations of Veli-Akkulam Lake and compared with a regional reference lake Vellayani of south India. Seasonal variations of 14 different physicochemical parameters analyzed were as follows: pH (6.42-7.48, water temperature (26.0-31.28°C, salinity (0.50-26.81 ppt, electrical conductivity (47-20656.31 µs/cm, dissolved oxygen (0.078-7.65 mg/L, free carbon-dioxide (3.8-51.8 mg/L, total hardness (27.20-2166.6 mg/L, total dissolved solids (84.66-4195 mg/L, biochemical oxygen demand (1.57-25.78 mg/L, chemical oxygen demand (5.35-71.14 mg/L, nitrate (0.012-0.321 µg/ml, nitrite (0.24-0.79 µg/ml, phosphate (0.04-5.88 mg/L, and sulfate (0.27-27.8 mg/L. Cluster analysis showed four clusters based on the similarity of water quality characteristics among sampling stations during three different seasons (pre-monsoon, monsoon and post-monsoon. Multidimensional scaling in conjunction with cluster analysis identified four distinct groups of sites with varied water quality conditions such as upstream, transitional and downstream conditions  in Veli-Akkulam Lake and a reference condition at Vellayani Lake. Principal Component Analysis showed that Veli-Akkulam Lake was seriously deteriorated in water quality while acceptable water quality conditions were observed at reference lake Vellayani. Thus the present study could estimate the effectiveness of multivariate statistical approaches for assessing water quality conditions in lakes.

  1. Rotifer community structure and assessment of water quality in Yangcheng Lake (United States)

    Chen, Lijing; Liu, Qiao; Peng, Ziran; Hu, Zhongjun; Xue, Junzeng; Wang, Wu


    Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and Q B/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894 ± 1 006 ind./L and 12.47 ± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella cochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature ( R = 0.209, P = 0.003; R = 0.446, P = 0.000), but the peak density showed two lags in response to chl a. According to the Jaccard similarity index ( S J), the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H', Margalef richness index D and Pielou evenness index J were 1.96 ± 0.34, 1.61 ± 0.50 and 0.77 ± 0.10, respectively. In all four areas of Yangcheng Lake, β-mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.

  2. Assessment of Water and Sediment Physical-Chemical Composition in the West Coast of Maracaibo Lake

    Directory of Open Access Journals (Sweden)

    Jorge Moronta-Riera


    Full Text Available The objective of this investigation was to determine the physical and chemical composition of the water streams and sediments of the Maracaibo Lake in three sampling areas located in Tía Juana, Lagunillas and Ceuta in order to know the level of contamination and assess water quality based on permissible values established by the 883 Decree. The results indicate that the overall hydrocarbon concentrations in the water and sediments are above permissible levels. It is concluded that petroleum prospection is the root cause of the lake contamination.

  3. Satellite winds as a tool for offshore wind resource assessment: The Great Lakes Wind Atlas

    DEFF Research Database (Denmark)

    Doubrawa, Paula; Barthelmie, Rebecca Jane; Pryor, Sara C.


    This work presents a new observational wind atlas for the Great Lakes, and proposes a methodology to combine in situ and satellite wind observations for offshore wind resource assessment. Efficient wind energy projects rely on accurate wind resource estimates, which are complex to obtain offshore...... the North American Regional Reanalysis. Generalized wind climates are obtained for each buoy and coastal site with the wind model WAsP, and combined into a single wind speed estimate for the Great Lakes region. The method of classes is used to account for the temporal sparseness in the SAR data set...

  4. Assessing the responses of creek chub (Semotilus atromaculatus) and pearl dace (Semotilus margarita) to metal mine effluents using in situ artificial streams in Sudbury, Ontario, Canada. (United States)

    Dubé, Monique G; MacLatchy, Deborah L; Hruska, Kimberly A; Glozier, Nancy E


    Mining of the world's second-largest nickel deposits in the area of Sudbury, Ontario, Canada, has caused acidification and metal saturation of some catchments. We conducted artificial stream studies in the years 2001 and 2002 to assess the effects of treated metal mine effluents (MMEs) from three different mining operations discharging to Junction Creek, Sudbury, on two fish species, creek chub (Semotilus atromaculatus) and pearl dace (Semotilus margarita). Treatments tested for 35 to 41 d included reference water, Garson MME (30%), Nolin MME (20%), and Copper Cliff MME (45%). In 2001, effects on chub included reduced survival and depressed testosterone levels (fivefold reduction) after exposure to all MMEs. In 2002, chub and dace survival were reduced to less than 60% in the Copper Cliff and Garson treatments. In addition, the total body weights of male and female dace were reduced after exposure to the Garson and Copper Cliff treatments. In 2001 and 2002, responses were most common to the 45% Copper Cliff and 30% Garson effluents, with consistent increases in nickel, rubidium, strontium, iron, lithium, thallium, and selenium observed across treatment waters and body tissues. More work is required to link observed effects to field effects and to identify multitrophic level responses of the ecosystem to the MMEs. The artificial stream studies provided a mechanism to identify changes in the endpoints of relevant fish species exposed to present-day metal mine discharges independent of historical depositions of metals in the Sudbury area.

  5. The Ontario Veterinary College Hip Certification Program — Assessing inter- and intra-observer repeatability and comparison of findings to those of the Orthopedic Foundation for Animals (United States)

    Chalmers, Heather J.; Nykamp, Stephanie; Lerer, Assaf


    In Canada, the Ontario Veterinary College (OVC) has offered radiographic screening for hip dysplasia for many years, but there are other options for this service including the Orthopedic Foundation for Animals (OFA). There are some differences between the OFA and the OVC methods, and this study compares the OVC and OFA hip certification results in 37 dogs. There was good agreement between the two programs but in some instances there was a difference in the pass/fail status of a dog. Neither the OFA nor the OVC was more likely to fail or pass a given dog. The repeatability of the OVC results was assessed by both inter- and intra-observer comparisons in 100 dogs. There was at least 86% agreement among and within radiologists, but in 5 cases the disagreement resulted in a difference in the pass/fail status of the dog. These results illustrate the inherent variation in radiographic hip evaluation and highlight the importance of consensus grading practices to improve the accuracy of hip evaluation. PMID:23814300

  6. Processes under Outbursts of Mountain Lakes and Model for Risk Assessment (United States)

    Valyaev, A. N.; Erochin, S. A.; Tusova, T. V.

    The mountain water objects such as large lakes and huge artificial water reservoirs play a very important role for human existence and life in many of the earth's regions. They are very dangerous and complex objects, where natural and man-made catastrophes may result to their outbursts with huge negative irreversible damages on environment and population. Also their large hydro constructions and dams are very attractive for directed terrorist attacks and realization of wide scale global ecologic and water terrorism. Also we present the model for their risk and damage assessments and some of its applications. Results will be presented for the classification of these lakes on their danger degree, management of their risks, development of counter measures for prediction/prevention of the lakes catastrophes and reducing possible negative damages.

  7. Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, China. (United States)

    He, Ping; Wang, Bao-zhong


    As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of China is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the ecotourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of China national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

  8. A freshwater biodiversity hotspot under pressure - assessing threats and identifying conservation needs for ancient Lake Ohrid (United States)

    Kostoski, G.; Albrecht, C.; Trajanovski, S.; Wilke, T.


    Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes. Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change. Among the major (well-known) threats with high impact are nutrient input (particularly of phosphorus), habitat conversion and silt load. Other threats are potentially of high impact but less well known. Such threats include pollution with hazardous substances (from sources such as mines, former industries, agriculture) or climate change. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species measures, international

  9. A freshwater biodiversity hotspot under pressure - assessing threats and identifying conservation needs for ancient Lake Ohrid (United States)

    Kostoski, G.; Albrecht, C.; Trajanovski, S.; Wilke, T.


    Freshwater habitats and species living in freshwater are generally more prone to extinction than terrestrial or marine ones. Immediate conservation measures for world-wide freshwater resources are thus of eminent importance. This is particularly true for so called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, the European biodiversity hotspot, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes. Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change. Of the 11 IUCN (International Union for Conservation of Nature and Natural Resources) threat classes scored, seven have moderate and three severe impacts. These latter threat classes are energy production and mining, biological resource use, and pollution. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species measures, international conservation

  10. Clinical balance assessment: perceptions of commonly-used standardized measures and current practices among physiotherapists in Ontario, Canada

    National Research Council Canada - National Science Library

    Sibley, Kathryn M; Straus, Sharon E; Inness, Elizabeth L; Salbach, Nancy M; Jaglal, Susan B


    Balance impairment is common in multiple clinical populations, and comprehensive assessment is important for identifying impairments, planning individualized treatment programs, and evaluating change over time...

  11. Lessons learned from Ontario wind energy disputes (United States)

    Fast, Stewart; Mabee, Warren; Baxter, Jamie; Christidis, Tanya; Driver, Liz; Hill, Stephen; McMurtry, J. J.; Tomkow, Melody


    Issues concerning the social acceptance of wind energy are major challenges for policy-makers, communities and wind developers. They also impact the legitimacy of societal decisions to pursue wind energy. Here we set out to identify and assess the factors that lead to wind energy disputes in Ontario, Canada, a region of the world that has experienced a rapid increase in the development of wind energy. Based on our expertise as a group comprising social scientists, a community representative and a wind industry advocate engaged in the Ontario wind energy situation, we explore and suggest recommendations based on four key factors: socially mediated health concerns, the distribution of financial benefits, lack of meaningful engagement and failure to treat landscape concerns seriously. Ontario's recent change from a feed-in-tariff-based renewable electricity procurement process to a competitive bid process, albeit with more attention to community engagement, will only partially address these concerns.

  12. Assessment of the risk of drowning at low-head dams used as sea lamprey barriers in Ontario[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, K.A.; Thomson, J.; Amos, M. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Civil and Geological Engineering; Hallett, A. [A. Hallett, Sault Ste. Marie, ON (Canada); Aktar, A. [Indian Inst. of Technology, Kanpur (India). Dept. of Civil Engineering; Katopodis, C. [Fisheries and Oceans Canada, Winnipeg, MB (Canada). Freshwater Inst.


    In 2003, there were 54 fixed-crest lamprey barriers used in the Great Lakes region, with more construction planned. Although the barriers are relatively small structures of about 1-2 m in height, they present a drowning hazard. On the downstream side of the structure, a submerged hydraulic jump creates a strong vortex flow that even an experienced swimmer cannot escape. This study developed a method to assess the risk of hazardous flows at the barrier sites to enable dam owners to decide whether or not mitigative measures need to be undertaken at their sites. This hazard assessment was demonstrated for 2 existing lamprey barriers in Ontario, namely the Duffins Creek Barrier at Ajax and the Little Otter Creek Barrier near Straffordville. However, the work can be applied to the dam safety assessment and the development of potential mitigative strategies for drowning at other low-head dams and weirs. A flow-duration curves was developed for each site in order to determine the risk of having a drowning hazard at the barrier sites. In the flow-duration analysis, the percentage time, or probability, that a given flow rate was equalled or exceeded was calculated directly from observations of the average daily discharge in the channel. 18 refs., 1 tab., 7 figs.

  13. Human-mediated and natural dispersal of an invasive fish in the eastern Great Lakes. (United States)

    Johansson, Mattias L; Dufour, Bradley A; Wellband, Kyle W; Corkum, Lynda D; MacIsaac, Hugh J; Heath, Daniel D


    The globally invasive Round Goby (Neogobius melanostomus) was introduced to the Great Lakes around 1990, spreading widely and becoming the dominant benthic fish in many areas. The speed and scope of this invasion is remarkable and calls into question conventional secondary spread models and scenarios. We utilized nine microsatellites to identify large-scale genetic structure in Round Goby populations in the eastern Great Lakes, and assessed the role of colonization vs. secondary transport and dispersal in developing this structure. We identified three clusters, corresponding with Lake Huron, eastern Lake Erie, and western Lake Erie plus eastern Lake Ontario, along with three highly divergent populations. Bottleneck analysis identified founder effects in two divergent populations. Regression analyses of isolation by distance and allelic richness vs. distance from the initial invasion site were consistent with limited migration. However, some populations in eastern Lake Erie and Lake Ontario showed anomalously low genetic distance from the original site of colonization, consistent with secondary transport of large numbers of individuals via ballast water. We conclude that genetic structure of Round Goby in the Great Lakes principally resulted from long-distance secondary transport via ballast water with additional movement of individual via bait buckets and natural dispersal. The success of Round Gobies represents an interesting model for colonization characterization; however, those same attributes present significant challenges for conservation and fisheries management. Current management likely prevents many new species from arriving in the Great Lakes, but fails to address the transport of species within the lakes after they arrive; this is an issue of clear and pressing importance.

  14. Development and application of sedimentary pigments for assessing effects of climatic and environmental changes on subarctic lakes in northern Sweden

    DEFF Research Database (Denmark)

    Reuss, Nina Steenberg; Leavitt, Peter R.; Hall, Roland I.


    A surface-sediment survey of pigments in 100 lakes in the Scandes Mountains, northern Sweden, was combined with a reconstruction of Holocene sedimentary pigments from Lake Seukokjaure to assess the major factors regulating phototrophic communities, and how these controls may have changed during...... to the modern tree line. The spatial survey of sedimentary pigments was analyzed using principle components analysis (PCA) and redundancy analysis (RDA). PCA explained 73-83% of variance in pigment abundance and composition, whereas RDA explained 22-32% of variation in fossil assemblages. Dissolved organic...... carbon (DOC) content of lake water, sediment d13C, maximum lake depth, elevation and lake-water conductivity were all identified as environmental variables with significant association with pigment abundances in the spatial survey, although phototrophic communities of lakes situated in different...

  15. Shoreline features of Titan's Ontario Lacus from Cassini/VIMS observations (United States)

    Barnes, J.W.; Brown, R.H.; Soderblom, J.M.; Soderblom, L.A.; Jaumann, R.; Jackson, B.; Le, Mouelic S.; Sotin, Christophe; Buratti, B.J.; Pitman, K.M.; Baines, K.H.; Clark, R.N.; Nicholson, P.D.; Turtle, E.P.; Perry, J.


    We analyze observations of Titan's south polar lake Ontario Lacus obtained by Cassini's Visual and Infrared Mapping Spectrometer during the 38th flyby of Titan (T38; 2007 December 5). These near-closest-approach observations have the highest signal-to-noise, the finest spatial resolution, and the least atmospheric influence of any near-infrared lake observation to date. We use the large, spatially flat, and low-albedo interior of Ontario Lacus as a calibration target allowing us to derive an analytical atmospheric correction for emission angle. The dark lake interior is surrounded by two separate annuli that follow the lake interior's contours. The inner annulus is uniformly dark, but not so much as the interior lake, and is generally 5-10 kilometers wide at the lake's southeastern margin. We propose that it represents wet lakebed sediments exposed by either tidal sloshing of the lake or seasonal methane loss leading to lower lake-volume. The exterior annulus is bright and shows a spectrum consistent with a relatively low water-ice content relative to the rest of Titan. It may represent fine-grained condensate deposits from a past era of higher lake level. Together, the annuli seem to indicate that the lake level for Ontario Lacus has changed over time. This hypothesis can be tested with observations scheduled for future Titan flybys. ?? 2008 Elsevier Inc.

  16. Assessing the toxicity and risk of salt-impacted winter road runoff to the early life stages of freshwater mussels in the Canadian province of Ontario. (United States)

    Prosser, R S; Rochfort, Q; McInnis, R; Exall, K; Gillis, P L


    In temperate urbanized areas where road salting is used for winter road maintenance, the level of chloride in surface waters has been increasing. While a number of studies have shown that the early-life stages of freshwater mussels are particularly sensitive to salt; few studies have examined the toxicity of salt-impacted winter road runoff to the early-life stages of freshwater mussels to confirm that chloride is the driver of toxicity in this mixture. This study examines the acute toxicity of field-collected winter road runoff to the glochidia of wavy-rayed lampmussels (Lampsilis fasciola) (48 h exposure) and newly released juvenile fatmucket mussels (Lampsilis siliquoidea) (road run-off created with moderately hard synthetic water (∼80 mg CaCO3/L) were 1177 (95% confidence interval (CI): 1011-1344 mg Cl-/L) and 2276 mg Cl-/L (95% CI: 1698-2854 mg Cl-/L), respectively. These effect concentrations correspond with the toxicity of chloride reported in other studies, indicating that chloride is likely the driver of toxicity in salt-impacted road-runoff, with other contaminants (e.g., metals, polycyclic aromatic hydrocarbons) playing a de minimis role. Toxicity data from the current study and literature and concentrations of chloride in the surface waters of Ontario were used to conduct a probabilistic risk assessment of chloride to early-life stage freshwater mussels. The assessment indicated that chronic exposure to elevated chloride levels could pose a risk to freshwater mussels; further investigation is warranted to ensure that the most sensitive organisms are protected. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  17. Assessing factors underlying variation of CO2 emissions in boreal lakes vs. reservoirs. (United States)

    Tadonléké, Rémy D; Marty, Jérôme; Planas, Dolors


    Reservoirs and lakes were compared to test the hypothesis that they are similar with respect to factors driving the variation in CO(2) emissions to the atmosphere. Understanding this variation is necessary for the assessment of the contribution of these freshwater ecosystems to the global carbon cycle. This study, in contrast to previous ones, included analyses of the relationships between CO(2) emissions and microbial communities. Pooled data (lakes and reservoirs) showed that variations in CO(2) emissions were strongly related to variations in temperature, dissolved organic matter (DOM) quality, and bacterial production (BP). Results also showed that lakes were characterized by higher water temperature, lower DOM quality, larger size of Daphnia, and enriched δ(13) C zooplankton compared to reservoirs. Moreover, interactions within plankton communities and relationships between CO(2) emissions and zooplankton δ(13) C signatures differed in lakes vs. reservoirs, indicating among-system type differences in food web structure and carbon cycling. As a result of these ecosystem-type characteristics, CO(2) emission variation was mainly explained by temperature and BP in lakes, and by DOM quality and the ratio of phytoplankton biomass to microheterotroph biomass in reservoirs. These results showed that differences in temperature and DOM quality between lakes and reservoirs translate into differences in microbial interactions and ultimately in the importance of factors driving CO(2) emissions to the atmosphere. They indicated that considering microbial communities and environmental variables such as temperature and DOM quality can help improve our understanding of the variation in CO(2) emissions from freshwater ecosystems. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  18. Sources appointment and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in sediments of Erhai Lake, a low-latitude and high-altitude lake in southwest China. (United States)

    Hezhong, Yuan; Enlou, Zhang; Qi, Lin; Rong, Wang; Enfeng, Liu


    Sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed from the surficial sediments in Erhai Lake, a plateau lake in China. The results showed that except for acenaphthylene (Ace) Ace and Dibenz(a,h)anthracene (DBA), the central region contained individual PAHs at concentrations lower than those in other lake regions. Total concentration of the PAHs (ΣPAHs) in the sediments from Erhai Lake ranged from 32.42 to 558.53 mg/kg with a mean value of 256.70 mg/kg. The maximum value of ΣPAHs was observed in the north region of the lake and more than 10-fold higher than the minimum values. Moreover, high molecular weight (HMW) PAHs, especially 5-ring PAHs, accounted for higher ratios up to 76 % relative to other PAHs compound in almost all sampling sites. Molecular diagnostic ratios including anthtacene (Ant)/(Ant + phenanthrene (Phe)), fluoranthene (Flt)/(Flt + pyrene (Pyr)), benz(a)anthracene (BaA)/(BaA + chrysene (Chr)), and indeno(1,2,3-cd)pyrene (IPY)/(IPY + benz(g,h,i)perylene (BPE)) were recorded at all sampling sites and indicated that the origin of PAHs in Erhai Lake was predominately pyrolytic. Furthermore, principal component analysis with component dominating by HMW PAHs showed that combustion origins were the primary contamination sources of PAHs in the sediments of Erhai Lake. Finally, ecological risk assessment indicated that the sediments from Erhai Lake are exposed to potential low risk for ΣPAHs, and the ecological risk decreases in the order of northern region > southern region > central region.

  19. Spatiotemporal assessment of water chemistry in intermittently open/closed coastal lakes of Southern Baltic (United States)

    Astel, Aleksander M.; Bigus, Katarzyna; Obolewski, Krystian; Glińska-Lewczuk, Katarzyna


    Ionic profile, pH, electrolytic conductivity, chemical oxygen demand and concentration of selected heavy metals (Ni, Cu, Zn, Fe and Mn) were determined in water of 11 intermittently closed and open lakes and lagoons (ICOLLs) located in Polish coastline. Multidimensional data set was explored by the use of the self-organizing map (SOM) technique to avoid supervised and predictable division for fully isolated, partially and fully connected lakes. Water quality assessment based on single parameter's mean value allowed classification of majority of lakes to first or second class of purity according to regulation presenting classification approach applicable to uniform parts of surface waters. The SOM-based grouping revealed seven clusters comprising water samples of similar physico-chemical profile. Fully connected lakes were characterized by the highest concentration of components characteristic for sea salts (NaCl, MgCl2, MgSO4, CaSO4, K2SO4 and MgBr2), however spring samples from Łebsko were shifted to another cluster suggesting that intensive surface run-off and fresh-water inflow through Łupawa river decreases an impact of sea water intrusions. Forecasted characteristic of water collected in Resko Przymorskie lake was disturbed by high contamination by nitrites indicating accidental and local contamination due to usage of sodium nitrite for the curing of meat. Some unexpected sources of contamination was discovered in intermittently open and closed lakes. Presumably Zn contamination is due to use of wood preservatives to protect small wooden playgrounds or camping places spread around one of the lake, while increased concentration of Ni could be connected with grass and vegetation burning. Waters of Jamno lake are under the strongest anthropogenic impact due to inefficient removal of phosphates by waste water treatment plant and contamination by Fe and Mn caused by backwashing of absorption filters. Generally, the quality of ICOLLs' water was diversified, while

  20. Hydrogeochemical characteristics and assessment of water quality in the Al-Saad Lake, Abha Saudi Arabia (United States)

    Mallick, Javed


    Hydrogeochemical characteristics and assessment of water quality investigations have been carried out at Abha, located in Saudi Arabia, where Al-Saad Lake represents a rare example of natural endorheic lake. The ecosystem within and around the Al-Saad Lake including catchment area is of great social, cultural, aesthetic, environmental and economic values to Abha. Sampling and experiments of lake water has been carried out with the aim of characterizing the main physico-chemical parameters, such as DO, EC, TDS, Mg2+, Ca2+, Na+, K+, SO4 2-, Cl-, HCO3, NO3 - and F- concentration. The ordinary kriging (OK) method was used to produce the spatial patterns of water quality. The Result of DO (mean 5.38 mg/L) trend in Al-Saad Lake is not very encouraging as majority of the lake area is under DO stress or marginally above it. So, proper management strategies are needed to be formulated to protect flora and fauna of the lake. Furthermore, the chemical analysis results show the abundance of the major cations in the order Mg2+ > Ca2+ > Na+ > K+ whereas the abundance of anions are in the order SO4 2- > Cl- > HCO3 > NO3 - > F-. The result obtained in this investigation inferred that the cations in water i.e. sodium and iron are within the permissible limits but magnesium and potassium have exceeded the permissible limit. Whereas anions such as nitrate and fluoride are within the permissible range but chloride and sulphate have exceeded the permissible limits. The concentration of cation, magnesium (Mg) and potassium (K) in the lake water has exceeded the desirable range (30, 10 mg/L, respectively). This may be due to weathering and transported from rocks and particularly from sulphate deposits such as gypsum and anhydride and subsequently ends up in water. The concentration of anion, Sulphate (SO4) and chloride are above the desirable limit. The major source of bicarbonate are the carbonate rocks containing calcite (CaCO3) and dolomite (CaMg (CO3)2), Calcium (Ca) and Magnesium

  1. Erosion risk assessment along coastlines, rivers, and lakes (United States)

    Eidsvig, Unni; Harbitz, Carl B.; Issler, Dieter; Forsberg, Carl Fredrik; Høydal, Øyvind A.; Glimsdal, Sylfest; Frauenfelder, Regula


    An effect of the expected climate changes is that densely populated areas will be more exposed to natural hazards. There is a rising concern about geotechnical challenges associated with the transition zone between water and land, in particular with regard to erosion. This needs to be considered as part of the climate adaptation strategies in the society and applies to both coastal settlements and to settlements along rivers. Climate change, as reported by the IPCC, includes global warming, sea level rise as well as more precipitation, both with respect to intensity and frequency. A larger number of cities are expected to be affected by floods and with higher frequency. With large floods, the current speed in rivers and hence their erosion potential increases, leading to scouring along riverbanks, where important transport routes and other infrastructure are often located. The frequency and intensity of storm surges are expected to increase, as well as the risk of coastal erosion. In steep terrain, the likelihood of debris flows increases. The project "Multi-scale Erosion Risk under Climate Change" was initiated to prepare for such challenges as well as local climate adaptation. The project is an internal NGI strategic project funded by the Research Council of Norway for the period 2017 - 2019. The project aims to investigate relevant erosive and mass-flow processes in the coastal zone, along rivers, and in lakes. Further, the knowledge and tools to be developed within the project aim to reduce the risk associated with these processes, through appropriate land-use planning and innovative mitigation measures. The project is thematically subdivided into the following five work packages: WP1: Modelling of erosion processes in rivers, at the coast and in mass movements WP2: Floods, debris flows and sediment mobility in complex topography WP3: Coastal hydrodynamic processes WP4: Monitoring, warning and non-physical mitigation measures WP5: Dissemination and knowledge

  2. Metal pollution assessment in the surface sediment of Lake Nasser, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed E. Goher


    Full Text Available Eight heavy metals were measured seasonally in the sediment of Lake Nasser during 2013. 27 sites were chosen through 9 sectors across the main channel of the lake from Abu-Simbel to Aswan High Dam to assess the levels of the selected metals. The abundance of these metals was in the order of Fe > Mn > Zn > Cr > Ni > Cu > Pb > Cd, with mean concentrations of 12.41 mg/g, 279.56, 35.38, 30.79, 27.56, 21.78, 11.21 and 0.183 μg/g, respectively. Heavy metals are positively correlated with fine particles (mud fractions and organic matter accumulation. The results showed perspicuous spatial high significant differences (P < 0.01 for all the measured metals. Fe, Cr, Ni, Pb and Cd exhibited temporally high significant differences (P < 0.01 before and after the flood period. Four Pollution Indices were used for the environmental assessment of Lake Nasser sediment. The indices included three single indices, Enrichment Factor (EF, Index of Geo-accumulation (Igeo and Contamination Factor (CF. While the fourth, Pollution Load Index (PLI was an integrated index. The pollution indexes confirmed that the Lake Nasser sediment was not contaminated with these elements. Sediments of Lake Nasser may be represented as a reference for the pre-industrial background of River Nile Sediments downstream Aswan High Dam.

  3. Water-saving interventions assessment framework: an application for the Urmia Lake Restoration Program (United States)

    Shadkam, Somayeh; Oel, Pieter; Kabat, Pavel; Ludwig, Fulco


    Increasing water demand often results in unsustainable water use leaving insufficient amounts of water for sustaining natural environments. Therefore, to save natural resources water-saving interventions have been introduced to the environmental policy agenda in many (semi)-arid regions. Many policies, however, have failed reaching their objectives to increase water availability for the environment. This calls for a comprehensive tool to assess water-saving policies. Therefore, this study introduces a constructive framework to assess the policies by estimating five components: 1) Total water demand under socio-economic scenarios, 2) Water supply under climate change scenarios, 3) Water withdrawal for different sectors, 4) Water depletion and 5) Environmental flow. The framework, was applied to assess Urmia Lake Restoration Program (ULRP), which aims to restore the drying Urmia Lake in north-western Iran by increasing the lake inflow by 3.1×106m3yr-1. Results suggest that although the ULRP helps to increase inflow by up to 57% it is unlikely to fully reach its target. The analysis shows that there are three main reasons for the potential poor performance. The first reason is decreasing return flows due to increasing irrigation efficiency. This means that the expected increase in lake inflow volume is smaller than the volume saved by increasing irrigation efficiency. The second reason is increased depletion which is due to neglecting the fact that agricultural water demand is currently higher than available water for agriculture. As a result, increasing water use efficiency may result in increased water depletion. The third reason is ignoring the potential impact of climate change, which might decrease future water availability by 3% to 15%. Our analysis suggests that to reach the intervention target, measures need to focus on reducing Water demand and Water depletion rather than on reducing Water withdrawals. The assessment framework can be used to comprehensively

  4. An Investigation of GIS Overlay and PCA Techniques for Urban Environmental Quality Assessment: A Case Study in Toronto, Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Kamil Faisal


    Full Text Available The United Nations estimates that the global population is going to be double in the coming 40 years, which may cause a negative impact on the environment and human life. Such an impact may instigate increased water demand, overuse of power, anthropogenic noise, etc. Thus, modelling the Urban Environmental Quality (UEQ becomes indispensable for a better city planning and an efficient urban sprawl control. This study aims to investigate the ability of using remote sensing and Geographic Information System (GIS techniques to model the UEQ with a case study in the city of Toronto via deriving different environmental, urban and socio-economic parameters. Remote sensing, GIS and census data were first obtained to derive environmental, urban and socio-economic parameters. Two techniques, GIS overlay and Principal Component Analysis (PCA, were used to integrate all of these environmental, urban and socio-economic parameters. Socio-economic parameters including family income, higher education and land value were used as a reference to assess the outcomes derived from the two integration methods. The outcomes were assessed through evaluating the relationship between the extracted UEQ results and the reference layers. Preliminary findings showed that the GIS overlay represents a better precision and accuracy (71% and 65%, respectively, comparing to the PCA technique. The outcomes of the research can serve as a generic indicator to help the authority for better city planning with consideration of all possible social, environmental and urban requirements or constraints.

  5. Great Lakes prey fish populations: a cross-basin overview of status and trends based on bottom trawl surveys, 1978-2013 (United States)

    Gorman, Owen T.; Weidel, Brian C.


    Lake Michigan. In general, trends in year-class strengths were less concordant across the basin and only coregonids showed statistical agreement across the upper Great Lakes. The appearance of strong and moderate year-classes of Bloater in Lake Huron in 2005- 2011 countered the trend of continuing weak year-classes of coregonids in Lakes Michigan and Superior. Not shown in our analysis is the appearance of the 2013 year-class of Bloater in Huron, the largest to date. There was no agreement in cross-basin trends in year-class strengths for Rainbow Smelt and Alewife, although there was agreement between pairs of lakes. Although there was statistical agreement in trends of age-0 and older Round Goby biomass among lakes where this species has successfully invaded (Michigan, Huron, Erie and Ontario), temporal patterns of biomass in each lake were different. Round Goby may be approaching equilibrium in Lake Erie, peaking in Lake Huron, and expanding in Lake Michigan. The trend in Lake Ontario remains unclear. Declining abundance in Lake Erie has corresponded with evidence that Round Goby have become increasingly incorporated into piscivore diets, e.g., Lake Trout, Walleye, Smallmouth Bass, Yellow Perch, and Burbot in Lakes Michigan, Huron, Erie, and Ontario. Round Goby continue to be absent from spring bottom trawl assessments in Lake Superior, but their presence in the harbors and embayments of Duluth and Thunder Bay (U.S. Geological Survey and Ontario Ministry of Natural Resources, unpublished data), suggests that there is potential for future colonization.

  6. DNA barcoding as a tool for Great Lakes biological assessment (United States)

    Enumerating organisms found in water samples in support of biodiversity and biological condition assessment is a mainstay of aquatic ecology, yet can require considerable resources and expertise. DNA-based identification of mixed-organism samples offers the potential to greatly ...

  7. Environmental Assessment : Chronic wasting disease management during an epidemic occurrence at Crescent Lake National Wildlife Refuge, Garden County, Nebraska (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is needed to manage for chronic wasting disease on Crescent Lake NWR. There were two alternatives seriously considered: no action and...

  8. Assessing condition of macroinvertebrate communities and bed sediment toxicity in the Rochester Embayment Area of Concern, New York, USA (United States)

    Duffy, Brian; George, Scott D.; Baldigo, Barry P.; Smith, Alexander J.


    The United States and Canada agreed to restore the chemical, physical, and biological integrity of the Great Lakes ecosystem under the first Great Lakes Water Quality Agreement in 1972. The lowest reach of the Genesee River and the Rochester Embayment on Lake Ontario between Bogus Point and Nine Mile Point, including Braddock Bay, were designated as an Area of Concern (AOC) due to effects of contaminated sediments and physical disturbance on several beneficial uses. Following sediment remedial efforts and with conditions improving in the AOC, the present study was conducted to reevaluate the status of the benthic macroinvertebrate (benthos) beneficial use impairment (BUI). Benthic macroinvertebrate community assessments and 10-day Chironomus dilutus bioassays were used to test the hypotheses that sediments within the AOC were no more toxic than sediments from surrounding reference areas. The study was separated into three discrete systems (Genesee River, Lake Ontario, and Braddock Bay) and non-parametric analyses determined that a multimetric index of benthic macroinvertebrate community integrity was significantly higher at AOC sites compared to reference sites on the Genesee River and in Braddock Bay while AOC and reference sites on Lake Ontario did not differ significantly. Survival and growth of C. dilutus were also similar between AOC and reference sites for each system with the exception of significantly higher growth at reference sites on Lake Ontario. Results generally indicated that the condition of benthos and toxicity of sediment of the Rochester Embayment AOC are similar to or better than that in the surrounding area.

  9. An assessment of ONRAB oral rabies vaccine persistence in free-ranging mammal populations in Ontario, Canada. (United States)

    Sobey, K G; Walpole, A A; Rosatte, R; Fehlner-Gardiner, C; Donovan, D; Bachmann, P; Coulson, S; Beresford, A; Bruce, L; Kyle, C J


    ONRAB is a rabies glycoprotein recombinant human adenovirus type 5 oral vaccine developed for application in baits to control rabies in wildlife populations. Prior to widespread use of ONRAB, both the safety and effectiveness of this vaccine required investigation. While previous research has focused on field performance and the persistence and pathogenicity of ONRAB in captive animals, we sought to examine persistence and shedding of ONRAB in populations of free-ranging target and non-target mammals. We collected oral and rectal swab samples from 84 red foxes, 169 striped skunks, and 116 raccoons during 2007 and 2008 in areas where ONRAB vaccine baits were distributed. We also analyzed 930 tissue samples, 135 oral swab and 138 rectal swab samples from 155 non-target small mammals from 10 species captured during 2008 at sites treated with high densities of ONRAB vaccine baits. Samples were screened for the presence and quantity of ONRAB DNA using quantitative real-time PCR. None of the samples that we analyzed from target and non-target species contained quantities of ONRAB greater than 10(3)EU/mL of ONRAB DNA which is a limit that has previously been applied to assess viral shedding. This study builds on similar research and suggests that replication of ONRAB in animals is short-lived and the likelihood of horizontal transmission to other organisms is low. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Ecological Health and Water Quality Assessments in Big Creek Lake, AL (United States)

    Childs, L. M.; Frey, J. W.; Jones, J. B.; Maki, A. E.; Brozen, M. W.; Malik, S.; Allain, M.; Mitchell, B.; Batina, M.; Brooks, A. O.


    Big Creek Lake (aka J.B. Converse Reservoir) serves as the water supply for the majority of residents in Mobile County, Alabama. The area surrounding the reservoir serves as a gopher tortoise mitigation bank and is protected from further development, however, impacts from previous disasters and construction have greatly impacted the Big Creek Lake area. The Escatawpa Watershed drains into the lake, and of the seven drainage streams, three have received a 303 (d) (impaired water bodies) designation in the past. In the adjacent ecosystem, the forest is experiencing major stress from drought and pine bark beetle infestations. Various agencies are using control methods such as pesticide treatment to eradicate the beetles. There are many concerns about these control methods and the run-off into the ecosystem. In addition to pesticide control methods, the Highway 98 construction projects cross the north area of the lake. The community has expressed concern about both direct and indirect impacts of these construction projects on the lake. This project addresses concerns about water quality, increasing drought in the Southeastern U.S., forest health as it relates to vegetation stress, and state and federal needs for improved assessment methods supported by remotely sensed data to determine coastal forest susceptibility to pine bark beetles. Landsat TM, ASTER, MODIS, and EO-1/ALI imagery was employed in Normalized Difference Vegetation Index (NDVI) and Normalized Difference Moisture Index (NDMI), as well as to detect concentration of suspended solids, chlorophyll and water turbidity. This study utilizes NASA Earth Observation Systems to determine how environmental conditions and human activity relate to pine tree stress and the onset of pine beetle invasion, as well as relate current water quality data to community concerns and gain a better understanding of human impacts upon water resources.

  11. Fuzzy Cognitive Maps for Glacier Hazards Assessment: Application to Predicting the Potential for Glacier Lake Outbursts (United States)

    Furfaro, R.; Kargel, J. S.; Fink, W.; Bishop, M. P.


    Glaciers and ice sheets are among the largest unstable parts of the solid Earth. Generally, glaciers are devoid of resources (other than water), are dangerous, are unstable and no infrastructure is normally built directly on their surfaces. Areas down valley from large alpine glaciers are also commonly unstable due to landslide potential of moraines, debris flows, snow avalanches, outburst floods from glacier lakes, and other dynamical alpine processes; yet there exists much development and human occupation of some disaster-prone areas. Satellite remote sensing can be extremely effective in providing cost-effective and time- critical information. Space-based imagery can be used to monitor glacier outlines and their lakes, including processes such as iceberg calving and debris accumulation, as well as changing thicknesses and flow speeds. Such images can also be used to make preliminary identifications of specific hazardous spots and allows preliminary assessment of possible modes of future disaster occurrence. Autonomous assessment of glacier conditions and their potential for hazards would present a major advance and permit systematized analysis of more data than humans can assess. This technical leap will require the design and implementation of Artificial Intelligence (AI) algorithms specifically designed to mimic glacier experts’ reasoning. Here, we introduce the theory of Fuzzy Cognitive Maps (FCM) as an AI tool for predicting and assessing natural hazards in alpine glacier environments. FCM techniques are employed to represent expert knowledge of glaciers physical processes. A cognitive model embedded in a fuzzy logic framework is constructed via the synergistic interaction between glaciologists and AI experts. To verify the effectiveness of the proposed AI methodology as applied to predicting hazards in glacier environments, we designed and implemented a FCM that addresses the challenging problem of autonomously assessing the Glacier Lake Outburst Flow

  12. Spatial and temporal ecological risk assessment of unionized ammonia nitrogen in Tai Lake, China (2004-2015). (United States)

    Li, Yabing; Xu, Elvis Genbo; Liu, Wei; Chen, Yi; Liu, Hongling; Li, Di; Liu, Zhengtao; Giesy, John P; Yu, Hongxia


    Ammonia toxicity varies largely due to its pH- and temperature-dependent speciation (unionized ammonia nitrogen, NH3-N). The seasonal and long-term trend of ammonia risk in ecologically significant sections of Tai Lake, China was unknown. In this study, a two-level (deterministic and quantitative) method was developed to assess the special ecological risks posed by NH3-N at 37 sites during two seasons (February and September) of 2014 in Tai Lake. The long-term temporal (2004-2015) risk posed by NH3-N was also assessed by comparing annual quantitative risk values (probability of exceeding acute or chronic threshold values) in three key sections of Tai Lake. The results indicated the species living in the Tai Lake were at a 0.04% and 32.45% chance of risk due to acute exposure, and a 1.97% and 92.05% chance of risk due to chronic exposure in February and September of 2014, respectively. Alarmingly, the chronic ecological risks of NH3-N in the Lanshanzui section of the Tai Lake remained >30% from 2004 to 2011. The chronic risk of NH3-N in all three key sections of Tai Lake started to decrease in 2011. This was likely the consequence of the control practice of eutrophication implemented in the Tai Lake. A significant decline in diversity of the benthic invertebrate community of the Tai Lake could be associated with continuous exposure to ammonia over decades given different sensitivity of taxa to ammonia. The results laid a scientific foundation for risk assessment and management of ammonia in Tai Lake, China, and the developed two-level risk assessment approach can also be applied to other similar aquatic regions. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Assessment of water pollution induced by human activities in Burullus Lake using Landsat 8 operational land imager and GIS

    Directory of Open Access Journals (Sweden)

    Ahmed El-Zeiny


    Full Text Available Burullus Lake is the second largest lake along the Mediterranean Sea and represents one of the most subjected lakes to pollution at the delta’s coastline. The present study explores the use of Landsat data and GIS for assessing water pollution at Burullus Lake, Egypt. Multi-spectral Landsat-8 OLI image dated 2015 provided the necessary information to this study. Radiometric and atmospheric corrections were applied to the image. Land use/cover map was obtained to identify natural resources and types of human activities in the area surrounding the Lake. Three previously developed water quality empirical models for BOD, total nitrogen (TN and total phosphorus (TP were applied on the calibrated image. Then, a GIS model was generated to identify areas recording high levels of BOD, TN and TP. Results confirmed that the Lake water is subjected to pollution from multiple sources; particularly domestic and agricultural drains. Shallow water (i.e. Lake Shores, where human activities are influencing, reported high levels of water studied pollutants. The model indicated that south western and north eastern parts of the Lake are the most polluted parts, recording relatively high levels of BOD, TN and TP; >4.46 mg L−1, >18.33 mg L−1 and >15.59 mg L−1, respectively. Results were ascertained based on water quality investigations in relevant research studies on the Lake. It was concluded that Burullus Lake is extensively subjected to interrupting human activities which have a great negative impact on water quality. Also data-observation techniques and water quality empirical models were successful in assessing and mapping water pollution.

  14. Using scenarios to assess possible future impacts of invasive species in the Laurentian Great Lakes (United States)

    Lauber, T. Bruce; Stedman, Richard C.; Connelly, Nancy A; Rudstam, Lars G.; Ready, Richard C; Poe, Gregory L; Bunnell, David B.; Hook, Tomas O.; Koops, Marten A.; Ludsin, Stuart A.; Rutherford, Edward S; Wittmann, Marion E.


    The expected impacts of invasive species are key considerations in selecting policy responses to potential invasions. But predicting the impacts of invasive species is daunting, particularly in large systems threatened by multiple invasive species, such as North America’s Laurentian Great Lakes. We developed and evaluated a scenario-building process that relied on an expert panel to assess possible future impacts of aquatic invasive species on recreational fishing in the Great Lakes. To maximize its usefulness to policy makers, this process was designed to be implemented relatively rapidly and consider a range of species. The expert panel developed plausible, internally-consistent invasion scenarios for 5 aquatic invasive species, along with subjective probabilities of those scenarios. We describe these scenarios and evaluate this approach for assessing future invasive species impacts. The panel held diverse opinions about the likelihood of the scenarios, and only one scenario with impacts on sportfish species was considered likely by most of the experts. These outcomes are consistent with the literature on scenario building, which advocates for developing a range of plausible scenarios in decision making because the uncertainty of future conditions makes the likelihood of any particular scenario low. We believe that this scenario-building approach could contribute to policy decisions about whether and how to address the possible impacts of invasive species. In this case, scenarios could allow policy makers to narrow the range of possible impacts on Great Lakes fisheries they consider and help set a research agenda for further refining invasive species predictions.

  15. [Heavy metals pollution and its stability assessment of sediments in flowing rivers around lake Taihu]. (United States)

    Lu, Shao-Yong; Jiao, Wei; Jin, Xiang-Can; Yuan, Ye; Zhang, Ye; Li, Guang-De


    16 main inflow and outflow rivers around Lake Taihu were chosen as the research object, and the concentrations and distribution of four heavy metals (Pb, Cd, Cu and Zn) in the surface sediments of these river estuaries were detected. The pollution extent and stability were analyzed by using three-step sequential extraction method (BCR method). Aim of this study is to control heavy metal pollution of Lake Taihu and provide the basic information. Based on the results, the monitored river estuaries all had been contaminated by different degrees, and four heavy metals' concentrations all exceeded the threshold effect level (TEL) at most sampling sites. A distinct spatial heterogeneity was found in extracted fractions of these heavy metals distribution: northern rivers > southern rivers, inflow rivers > outflow rivers. The Stability Assessment Code (SAC) for different metals varied in the descending order of Cd, Zn, Pb and Cu. Compared with Pb and Cu, Cd and Zn had a higher second release potential and ecological risk.

  16. Seasonal trends in stable water isotopes and estimation of mean transit times for mesoscale catchments with mixed landuse in northeastern Ontario, Canada (United States)

    Chutko, Krys; James, April; McConnell, Chris; Yao, Huaxia


    Northern Ontario Precambrian shield basins include considerable surface water (large lakes, wetlands), moderate relief (e.g. 400 m), variation in surficial geology (clay belt soils, glacial tills), and increasingly, the influence of human landuse impact (e.g. urban, agriculture) that are characteristic of northern Ontario, Quebec and parts of Scandinavia. In northeastern Ontario, Lake Nipissing and the French River are part of an important headwater tributary that flows into Georgian Bay, Lake Huron. Lake Nipissing and its 13,000 km2 watershed is the source of water to local municipalities and First Nation communities, home to a First Nations fishery and 5{%} of Ontario's recreational angling, and contributes an estimated 100 million/year to Ontario's economy. In 2012, in response to increasing concerns over water quality and its implications for ecological and economic systems, and limited study of water quality and quantity in the Sturgeon River-Lake Nipissing-French River (SNF) basin, we initiated a stable water isotope (SWI) study to examine how landscape characteristics influence streamflow generation at scales where both natural landscape variation (e.g. surface reservoirs, clay belt soils, forested headwaters) and anthropogenic stressors (urbanization, agriculture) are anticipated to influence water quantity and quality. Bi-weekly to monthly monitoring of SWI in precipitation and streamflow began in January 2013. Catchments range in size from 35 to 6,875 km^2, with a median size of 197 km2 and median gradients from 1 to 8{%}. Landcover includes considerable agricultural (0-18{%}) and/or urban (0-47{%}) area. Lakes and wetlands together cover 10-25{%} of catchment area, with large individual lakes (e.g. Lake Temagami) acting as important reservoir storage for hydropower generation. The existing SWI dataset includes 2 years of streamflow data for 5 of the larger catchments, > 1 year for an additional 2 catchments, and 2 years of seasonal ice-off data for the

  17. Development of a zoning-based environmental-ecological-coupled model for lakes to assess lake restoration effect (United States)

    Xu, Mengjia; Zou, Changxin; Zhao, Yanwei


    Environmental/ecological models are widely used for lake management as they provide a means to understand physical, chemical and biological processes in highly complex ecosystems. Most research focused on the development of environmental (water quality) and ecological models, separately. Limited studies were developed to couple the two models, and in these limited coupled models, a lake was regarded as a whole for analysis (i.e., considering the lake to be one well-mixed box), which was appropriate for small-scale lakes and was not sufficient to capture spatial variations within middle-scale or large-scale lakes. This paper seeks to establish a zoning-based environmental-ecological-coupled model for a lake. The Baiyangdian Lake, the largest freshwater lake in Northern China, was adopted as the study case. The coupled lake models including a hydrodynamics and water quality model established by MIKE21 and a compartmental ecological model used STELLA software have been established for middle-sized Baiyangdian Lake to realize the simulation of spatial variations of ecological conditions. On the basis of the flow field distribution results generated by MIKE21 hydrodynamics model, four water area zones were used as an example for compartmental ecological model calibration and validation. The results revealed that the developed coupled lake models can reasonably reflected the changes of the key state variables although there remain some state variables that are not well represented by the model due to the low quality of field monitoring data. Monitoring sites in a compartment may not be representative of the water quality and ecological conditions in the entire compartment even though that is the intention of compartment-based model design. There was only one ecological observation from a single monitoring site for some periods. This single-measurement issue may cause large discrepancies particularly when sampled site is not representative of the whole compartment. The

  18. Climate change vulnerabilities- an integrated assessment in Pyramid Lake Paiute Indian Reservation (United States)

    Gautam, M. R.; Chief, K.; Wilde, K.; Smith, W.


    There are increasing concerns of potential climate change impacts that may place the Truckee River Basin in Nevada under unprecedented stress. We hypothesized that Pyramid Lake, a terminal lake of Truckee River, is prone to climatic as well as non-climatic stressors stemming from cumulative impacts from upstream urban areas and activities. Thus climate change may impair the ability of a major downstream water user, the Pyramid Lake Paiute Tribe (PLPT), to cope and adapt. The conventional approach in assessing vulnerability primarily focuses on hazards or biophysical vulnerabilities, such as water availability, floods, and drought impact. However, we found it inadequate to address the overall vulnerability of the PLPT. Thus in addition to biophysical vulnerabilities, intrinsic and external vulnerabilities were considered such as socio-economic variables (e.g. adaptive capacity) and policy and legal drivers (e.g. water rights). We proposed an elaborate framework for an integrated vulnerability assessment by adapting IPCC framework for vulnerability assessment, the Exposure-Sensitivity-Adaptive Capacity, and applied it to PLPT. Analysis of projected climate change dataset pointed towards increased incidences of floods and droughts and a warming trend over the whole basin with a higher rate at the lower basin in the future. In effort to understand how climatic trends trigger the vulnerability of PLPT, a multi-pronged approach was employed to understand key tribal livelihood assets including an in-depth analysis of the adaptive capacity of PLPT, a climate change survey, and a historical analysis of water conflict and negotiation. Results of the survey identified key natural assets as the lake, endangered fish, rangeland, and wetlands. The framework of a casual-loop diagram was developed in a system dynamic model that incorporated opinions of tribal stakeholders and other experts to evaluate how potential future climate changes might impact the endangered Cui ui fish

  19. Geographic distribution of ophthalmologists in Ontario: a 10-year review. (United States)

    Micieli, Jonathan A


    Previous studies have shown that access to appropriate care is lacking in low-income and rural areas. The goal of this study was to assess the geographic variation in the number of ophthalmologists in Ontario from the 2000 to 2010 fiscal years. Population-based analysis of the geographic distribution of Ontario ophthalmologists. All ophthalmologists who held an Ontario license and received payment through the Ontario Health Insurance Plan. Demographic information was obtained through Intellihealth Ontario's Medical Service Provider data source. Ontario counties were stratified into low-population (400000) groups. The ratio of ophthalmologists to population was greatest in low-population counties in 2000 (1:65601) and increased further in 2010 (1:75434). Only medium-sized counties saw an improvement in the ophthalmologist-to-population ratio over the study period. There was no statistical difference in the number of ophthalmologists per 100000 population between small, medium, and large counties. Counties with an ophthalmology residency program had a significantly higher number of ophthalmologists per population compared with those without one (1:18162 vs 1:44245). Geographic disparities exist in the distribution of ophthalmologists in Ontario. The highest ratios of ophthalmologists to population are found in areas with an ophthalmology residency program. New strategies are needed to improve the overall numbers and distribution of ophthalmologists to meet the demands of the aging population and reduce the burden of vision loss in Canada. Copyright © 2014 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  20. Modelling the Loktak Lake Basin to Assess Human Impact on Water Resources (United States)

    Eliza, K.


    Loktak Lake is an internationally important, Ramsar designated, fresh water wetland system in the state of Manipur, India. The lake was also listed under Montreux Record on account of the ecological modifications that the lake system has witnessed over time. A characteristic feature of this lake is the extensive occurrence of coalesced, naturally or otherwise, vegetative masses floating over it. A contiguous 40 km2 area of Phumdis, as these vegetative masses are locally referred to, also constitutes the only natural home of the endemic and endangered species of Manipur's brow-antlered deer popularly known as Sangai. Appropriately notified as Keibul Lamjao National Park by Government of India, this natural feature is known to be the world's largest floating park. Water quality and sediment deposition on account of soil erosion in its catchments are some of the emerging concerns along with a reported enhanced frequency and duration of flooding of the shore areas, reduced fish catch within a visibly deteriorated overall natural ecosystem. Disturbances of watershed processes, command area management practices, ineffective as indeed largely absent, waste management practices and management interventions linked to the Loktak Hydroelectric Project are often cited as the principal triggers that are seen to be responsible for the damage. An effective management protocol for the Lake requires a rigorous understanding of its hydrobiology and eco-hydrodynamics. The present study is carried out to establish such a characterization of the various rivers systems draining directly into the Lake using MIKE SHE, MIKE 11 HD and MIKE 11 ECO Lab modelling platforms. Water quality modelling was limited to dissolved oxygen (DO), biological oxygen demand (BOD) and water temperature. Model calibration was done using the available measured water quality data. The derived results were then investigated for causal correlation with anthropogenic influences to assess human impact on water

  1. Quantitative assessment of Naegleria fowleri and fecal indicator bacteria in brackish water of Lake Pontchartrain, Louisiana. (United States)

    Xue, Jia; Lamar, Frederica G; Zhang, Bowen; Lin, Siyu; Lamori, Jennifer G; Sherchan, Samendra P


    Brackish water samples from Lake Pontchartrain in Louisiana were assessed for the presence of pathogenic amoeba Naegleria fowleri, which causes primary amoebic meningoencephalitis (PAM). In our study, quantitative polymerase chain reaction (qPCR) methods were used to determine N. fowleri, E. coli, and enterococci in water collected from Lake Pontchartrain. N. fowleri target sequence was detected in 35.4% (56/158) of the water samples from ten sites around the lake. Statistically significant positive correlations between N. fowleri concentration and water temperature as well as E. coli (qPCR) were observed. Multiple linear regression (MLR) model shows seasonal factor (summer or winter) has significant effect on the concentration of N. fowleri, E. coli and enterococci (qPCR) concentration. Significant positive relationships between E. coli and enterococci was observed from both qPCR (r=0.25) and culture based method (r=0.54). Meanwhile, significant positive correlation between qPCR and culture based methods for enterococci concentration was observed (r=0.33). In our study, water temperature and E. coli concentration were indicative of N. fowleri concentrations in brackish water environment. Future research is needed to determine whether sediment is a source of N. fowleri found in the water column. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Assessment of Heavy Metal Pollution in Sediments of Inflow Rivers to Lake Taihu, China. (United States)

    Niu, Yong; Niu, Yuan; Pang, Yong; Yu, Hui


    Lake Taihu, the third-largest freshwater body in China, has many functions, including drinking water supply, flood control, cultivation, navigation, and tourism. In this study, sediment samples were collected at 31 sites from 11 inflow rivers in 2012, to investigate the distribution and concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr), and to assess their potential ecological risk. The highest mean concentration was found for Zn, followed by Cu, Cr, Pb, and Ni. Generally, heavy metal pollution was more serious in Wu Jingang River and Caoqiao River, probably because they receive large amounts of wastewater from various local industrial enterprises. The potential ecological risk values of the heavy metals were larger than 120 in more than 25.8% of the sediment samples, indicating a very high risk. The largest ecological risk was due to copper. Furthermore, the results of a principal component analysis and subsequent analysis of variance showed that heavy metal concentrations in the sediment of inflow rivers were higher than those of the lake, which created a large hazard for the aquatic ecosystems of Lake Taihu.

  3. A needs assessment for climate change education in the Great Lakes region (United States)

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


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

  4. Spatial Distribution and Fuzzy Health Risk Assessment of Trace Elements in Surface Water from Honghu Lake. (United States)

    Li, Fei; Qiu, Zhenzhen; Zhang, Jingdong; Liu, Chaoyang; Cai, Ying; Xiao, Minsi


    Previous studies revealed that Honghu Lake was polluted by trace elements due to anthropogenic activities. This study investigated the spatial distribution of trace elements in Honghu Lake, and identified the major pollutants and control areas based on the fuzzy health risk assessment at screening level. The mean total content of trace elements in surface water decreased in the order of Zn (18.04 μg/L) > Pb (3.42 μg/L) > Cu (3.09 μg/L) > Cr (1.63 μg/L) > As (0.99 μg/L) > Cd (0.14 μg/L), within limits of Drinking Water Guidelines. The results of fuzzy health risk assessment indicated that there was no obvious non-carcinogenic risk to human health, while carcinogenic risk was observed in descending order of As > Cr > Cd > Pb. As was regarded to have the highest carcinogenic risk among selected trace elements because it generally accounted for 64% of integrated carcinogenic risk. Potential carcinogenic risk of trace elements in each sampling site was approximately at medium risk level (10-5 to 10-4). The areas in the south (S4, S13, and S16) and northeast (S8, S18, and S19) of Honghu Lake were regarded as the risk priority control areas. However, the corresponding maximum memberships of integrated carcinogenic risk in S1, S3, S10-S13, S15, and S18 were of relatively low credibility (50-60%), and may mislead the decision-makers in identifying the risk priority areas. Results of fuzzy assessment presented the subordinate grade and corresponding reliability of risk, and provided more full-scale results for decision-makers, which made up for the deficiency of certainty assessment to a certain extent.

  5. An assessment of the physico–chemical properties of Moro lake ...

    African Journals Online (AJOL)

    Nitrate & phosphate were high showing a case of cultural eutrophication occurring from washing of nitrophophate fertilizer from nearby farmlands into the lake. In general, the surface water quality of the lake is good and the lake is productive and eutrophic. Keywords: Physico-chemical factors, Moro lake, Eutrophication, ...

  6. Assessment of Atmospheric Correction Methods for Sentinel-2 MSI Images Applied to Amazon Floodplain Lakes

    Directory of Open Access Journals (Sweden)

    Vitor Souza Martins


    Full Text Available Satellite data provide the only viable means for extensive monitoring of remote and large freshwater systems, such as the Amazon floodplain lakes. However, an accurate atmospheric correction is required to retrieve water constituents based on surface water reflectance ( R W . In this paper, we assessed three atmospheric correction methods (Second Simulation of a Satellite Signal in the Solar Spectrum (6SV, ACOLITE and Sen2Cor applied to an image acquired by the MultiSpectral Instrument (MSI on-board of the European Space Agency’s Sentinel-2A platform using concurrent in-situ measurements over four Amazon floodplain lakes in Brazil. In addition, we evaluated the correction of forest adjacency effects based on the linear spectral unmixing model, and performed a temporal evaluation of atmospheric constituents from Multi-Angle Implementation of Atmospheric Correction (MAIAC products. The validation of MAIAC aerosol optical depth (AOD indicated satisfactory retrievals over the Amazon region, with a correlation coefficient (R of ~0.7 and 0.85 for Terra and Aqua products, respectively. The seasonal distribution of the cloud cover and AOD revealed a contrast between the first and second half of the year in the study area. Furthermore, simulation of top-of-atmosphere (TOA reflectance showed a critical contribution of atmospheric effects (>50% to all spectral bands, especially the deep blue (92%–96% and blue (84%–92% bands. The atmospheric correction results of the visible bands illustrate the limitation of the methods over dark lakes ( R W < 1%, and better match of the R W shape compared with in-situ measurements over turbid lakes, although the accuracy varied depending on the spectral bands and methods. Particularly above 705 nm, R W was highly affected by Amazon forest adjacency, and the proposed adjacency effect correction minimized the spectral distortions in R W (RMSE < 0.006. Finally, an extensive validation of the methods is required for

  7. Assessing river water quality using water quality index in Lake Taihu Basin, China. (United States)

    Wu, Zhaoshi; Wang, Xiaolong; Chen, Yuwei; Cai, Yongjiu; Deng, Jiancai


    Lake Taihu Basin, one of the most developed regions in China, has received considerable attention due to its severe pollution. Our study provides a clear understanding of the water quality in the rivers of Lake Taihu Basin based on basin-scale monitoring and a water quality index (WQI) method. From September 2014 to January 2016, four samplings across four seasons were conducted at 96 sites along main rivers. Fifteen parameters, including water temperature, pH, dissolved oxygen (DO), conductivity, turbidity (tur), permanganate index (CODMn), total nitrogen, total phosphorus, ammonium (NH4-N), nitrite, nitrate (NO3-N), calcium, magnesium, chloride, and sulfate, were measured to calculate the WQI. The average WQI value during our study period was 59.33; consequently, the water quality was considered as generally "moderate". Significant differences in WQI values were detected among the 6 river systems, with better water quality in the Tiaoxi and Nanhe systems. The water quality presented distinct seasonal variation, with the highest WQI values in autumn, followed by spring and summer, and the lowest values in winter. The minimum WQI (WQImin), which was developed based on a stepwise linear regression analysis, consisted of five parameters: NH4-N, CODMn, NO3-N, DO, and tur. The model exhibited excellent performance in representing the water quality in Lake Taihu Basin, especially when weights were fully considered. Our results are beneficial for water quality management and could be used for rapid and low-cost water quality evaluation in Lake Taihu Basin. Additionally, we suggest that weights of environmental parameters should be fully considered in water quality assessments when using the WQImin method. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Preliminary assessment of the cocial, economic and environmental impacts of Water Hyacinth in Lake Victoria basin and status of control


    Mailu, A.M.


    The paper presents preliminary data collected in an assessment of the social, economic and environmental impacts of water hyacinth in the Lake Victoria Basin. A summary of the status of control and strategies for the future is given. The report draws on field observations made, studies through interviews of affected communities and organisations, personal communications and published reports by scientists in the region. Lake Victoria, the world’s second largest freshwater body, su...

  9. Gun control and suicide in Ontario. (United States)

    Carrington, P J; Moyer, S


    To assess the impact of the 1978 Canadian gun control law on suicide rates in Ontario, the authors compared firearm and nonfirearm suicide rates for 1965-1977 with those for 1979-1989. There was a decrease in level and trend over time of firearm and total suicide rates and no indication of substitution of other methods. These decreases may be only partly due to the legislation.

  10. A DPSIR model for ecological security assessment through indicator screening: a case study at Dianchi Lake in China.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Given the important role of lake ecosystems in social and economic development, and the current severe environmental degradation in China, a systematic diagnosis of the ecological security of lakes is essential for sustainable development. A Driving-force, Pressure, Status, Impact, and Risk (DPSIR model, combined with data screening for lake ecological security assessment was developed to overcome the disadvantages of data selection in existing assessment methods. Correlation and principal component analysis were used to select independent and representative data. The DPSIR model was then applied to evaluate the ecological security of Dianchi Lake in China during 1988-2007 using an ecological security index. The results revealed a V-shaped trend. The application of the DPSIR model with data screening provided useful information regarding the status of the lake's ecosystem, while ensuring information efficiency and eliminating multicollinearity. The modeling approach described here is practical and operationally efficient, and provides an attractive alternative approach to assess the ecological security of lakes.

  11. Great Lakes Literacy Principles (United States)

    Fortner, Rosanne W.; Manzo, Lyndsey


    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 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.

  12. International Cooperative Programme for Assessment and Monitoring of Acidification of Rivers and Lakes. Programme Manual

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.; Forsius, M.; Jeffries, D. [and others


    The International Cooperative Programme for Assessment of Acidification of Rivers and lakes (ICP Waters) was established in 1985 by the UN/ECE Executive Body for the Convention of Long-Range Transboundary Air Pollution. Achieving the programme objectives requires that both the temporally intensive and regionally extensive data are collected on a continuing basis. To guide the development and harmonization of the various national contributions, a manual was worked out. The present report is an expanded and consolidated revision of that manual. 33 refs., 3 tabs.

  13. A Conceptual Framework for Assessment of Governance Performance of Lake Basins: Towards Transformation to Adaptive and Integrative Governance

    Directory of Open Access Journals (Sweden)

    Peter Emmanuel Cookey


    Full Text Available Governance is essential to lake basin management, but it is the most challenged and needs increased attention. Lake Basin Governance performance assessment is designed to measure the progress and impacts of policies, institutions and the roles of various actors in ensuring sustainability. It measures the performance of technical/operational, social/networks, and institutional arrangement that make up the socio-ecological system. Governance performance assessment becomes very necessary with over-emphasis of institutions on resources utilization and exploitation. The purpose of this paper is to present a governance performance assessment framework specifically for lake basins. The Adaptive Integrated Lake Basin Management (AILBM framework is a diagnostic and prescriptive performance assessment tool with an outcome to produce an adaptive and integrative system with equity, inclusiveness, transparency, accountability and flexibility to problem-solving and resilience. A case study on water governance performance assessment of the Songkhla Lake Basin (SLB in Thailand is provided for illustration and application and indicated a poor performance rating on governance in the Basin, revealing gaps, defects, strengths and weaknesses in the current system, necessary to recommend future improvements.


    Directory of Open Access Journals (Sweden)

    Fatgzim Latifi


    Full Text Available The aim of this study was to determine the concentrations of heavy metals (Zn, Cu, Pb, and Cd in the liver and gills of the common carp (Cyprinus carpio growing in Badovci and Batllava Lakes in Kosovo. Sixty healthy fish were collected from March to June 2016. The concentrations of metals in fish’s organs were determined by atomic absorption spectroscopy (AAS. Higher values of Zn, Cu, Pb, and Cd in the livers and gills were observed in individuals from Badovci Lake. Statistically significant differences in Zn, Cu, Pb, and Cd in the livers and gills were found between Badovci and Batllava Lakes. The Kishnica mine in the vicinity of Badovci Lake likely contributes to the high concentrations of these heavy metals in the water and fish. The results of this research will be useful for risk assessment by relevant institutions responsible for the monitoring and surveying of environmental pollution and food security and safety in Kosovo.

  15. Assessing the variability of glacier lake bathymetries and potential peak discharge based on large-scale measurements in the Cordillera Blanca, Peru (United States)

    Cochachin, Alejo; Huggel, Christian; Salazar, Cesar; Haeberli, Wilfried; Frey, Holger


    Over timescales of hundreds to thousands of years ice masses in mountains produced erosion in bedrock and subglacial sediment, including the formation of overdeepenings and large moraine dams that now serve as basins for glacial lakes. Satellite based studies found a total of 8355 glacial lakes in Peru, whereof 830 lakes were observed in the Cordillera Blanca. Some of them have caused major disasters due to glacial lake outburst floods in the past decades. On the other hand, in view of shrinking glaciers, changing water resources, and formation of new lakes, glacial lakes could have a function as water reservoirs in the future. Here we present unprecedented bathymetric studies of 124 glacial lakes in the Cordillera Blanca, Huallanca, Huayhuash and Raura in the regions of Ancash, Huanuco and Lima. Measurements were carried out using a boat equipped with GPS, a total station and an echo sounder to measure the depth of the lakes. Autocad Civil 3D Land and ArcGIS were used to process the data and generate digital topographies of the lake bathymetries, and analyze parameters such as lake area, length and width, and depth and volume. Based on that, we calculated empirical equations for mean depth as related to (1) area, (2) maximum length, and (3) maximum width. We then applied these three equations to all 830 glacial lakes of the Cordillera Blanca to estimate their volumes. Eventually we used three relations from the literature to assess the peak discharge of potential lake outburst floods, based on lake volumes, resulting in 3 x 3 peak discharge estimates. In terms of lake topography and geomorphology results indicate that the maximum depth is located in the center part for bedrock lakes, and in the back part for lakes in moraine material. Best correlations are found for mean depth and maximum width, however, all three empirical relations show a large spread, reflecting the wide range of natural lake bathymetries. Volumes of the 124 lakes with bathymetries amount to 0

  16. Small-area variations in utilization of abortion services in Ontario from 1985 to 1992.


    Ferris, L E; McMain-Klein, M


    OBJECTIVE: To assess interregional differences in the utilization of abortion services in Ontario from 1985 to 1992. DESIGN: Retrospective analysis of provincial therapeutic abortion database. SETTING: All hospitals conducting abortions between 1985 and 1992 and all free-standing abortion clinics conducting abortions between 1990 and 1992. POPULATION: All women in Ontario aged 15 to 44 years who underwent a therapeutic abortion in Ontario during the study period. OUTCOME MEASURES: Utilization...

  17. Rating impacts in a multi-stressor world: a quantitative assessment of 50 stressors affecting the Great Lakes. (United States)

    Smith, Sigrid D P; Mcintyre, Peter B; Halpern, Benjamin S; Cooke, Roger M; Marino, Adrienne L; Boyer, Gregory L; Buchsbaum, Andy; Burton, G A; Campbell, Linda M; Ciborowski, Jan J H; Doran, Patrick J; Infante, Dana M; Johnson, Lucinda B; Read, Jennifer G; Rose, Joan B; Rutherford, Edward S; Steinman, Alan D; Allan, J David


    Ecosystems often experience multiple environmental stressors simultaneously that can differ widely in their pathways and strengths of impact. Differences in the relative impact of environmental stressors can guide restoration and management prioritization, but few studies have empirically assessed a comprehensive suite of stressors acting on a given ecosystem. To fill this gap in the Laurentian Great Lakes, where considerable restoration investments are currently underway, we used expert elicitation via a detailed online survey to develop ratings of the relative impacts of 50 potential stressors. Highlighting the multiplicity of stressors in this system, experts assessed all 50 stressors as having some impact on ecosystem condition, but ratings differed greatly among stressors. Individual stressors related to invasive and nuisance species (e.g., dreissenid mussels and ballast invasion risk) and climate change were assessed as having the greatest potential impacts. These results mark a shift away from the longstanding emphasis on nonpoint phosphorus and persistent bioaccumulative toxic substances in the Great Lakes. Differences in impact ratings among lakes and ecosystem zones were weak, and experts exhibited surprisingly high levels of agreement on the relative impacts of most stressors. Our results provide a basin-wide, quantitative summary of expert opinion on the present-day influence of all major Great Lakes stressors. The resulting ratings can facilitate prioritizing stressors to achieve management objectives in a given location, as well as providing a baseline for future stressor impact assessments in the Great Lakes and elsewhere.

  18. Evaluation of triclosan in Minnesota lakes and rivers: Part I - ecological risk assessment. (United States)

    Lyndall, Jennifer; Barber, Timothy; Mahaney, Wendy; Bock, Michael; Capdevielle, Marie


    Triclosan, an antimicrobial compound found in consumer products, may be introduced into the aquatic environment via residual concentrations in municipal wastewater treatment effluent. We conducted an aquatic risk assessment that incorporated the available measured triclosan data from Minnesota lakes and rivers. Although only data reported from Minnesota were considered in the risk assessment, the developed toxicity benchmarks can be applied to other environments. The data were evaluated using a series of environmental fate models to ensure the data were internally consistent and to fill any data gaps. Triclosan was not detected in over 75% of the 567 surface water and sediment samples. Measured environmental data were used to model the predicted environmental exposures to triclosan in surface water, surface sediment, and biota tissues. Toxicity benchmarks based on fatty acid synthesis inhibition and narcosis were determined for aquatic organisms based, in part, on a species sensitivity distribution of chronic toxicity thresholds from the available literature. Predicted and measured environmental concentrations for surface water, sediment, and tissue were below the effects benchmarks, indicating that exposure to triclosan in Minnesota lakes and rivers would not pose an unacceptable risk to aquatic organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Ecological risk assessment and problem formulation for Lake Uluabat, a Ramsar State in Turkey. (United States)

    Salihoglu, Guray; Karaer, Feza


    Unlike the United States and the European Union, developing countries do not have sufficiently structured legal and institutional systems to apply certain environmental management tools such as ecological risk assessment. However, it is important for countries with valuable environmental and ecological resources to have appropriate tools and to strengthen their environmental management capabilities and capacities for the sake of those resources. The case study described in this paper attempts to be a case study towards developing environmental management plans, especially in developing countries. The problem formulation step of Ecological Risk Assessment applied in this study contributed to the basic elements of an environmental management plan including the following: the partnership-building process, prioritization of the problems and issues of the ecosystem, and development of the action plan. Based on the information provided by participants from a series of workshops held to develop an environmental management plan for Uluabat Lake, ecosystem risks were ranked and an action plan was formed. The results obtained with the aid of fuzzy set theory provided a base for identification of the action steps by allowing scientific information to be included in the process. The degree to which Uluabat Lake's problem formulation fits into the existing legal framework of Turkey is also analyzed in this paper.

  20. A climatic environmental performance assessment method for ecological city construction: Application to Beijing Yanqi Lake

    Directory of Open Access Journals (Sweden)

    Xiao-Yi Fang


    Full Text Available In contrast to the input perspective for evaluating planning metrics, this research takes the climatic environmental output effects as the starting point for assessing ecological city construction. Based on approaches such as observation data analysis, meteorological model simulation, and remote sensing, a set of climatic environmental performance assessment methods is developed and established. These methods mainly focus on surface ventilation assessment and urban thermal environment assessment. With the Yanqi Lake ecological development demonstration area located in Huairou district, Beijing as an example, the assessment of the local climatic environment before and after the construction are conducted, and relevant policy suggestions for urban planning and construction are presented. The results show that after development, the ventilation capacity will decrease overall and the ventilation potential index will decrease from 0.53 to 0.44. While this is not a large reduction, and is still at a favorable level, the ventilation potential in some local areas will markedly decrease. Furthermore, the thermal environment will become poorer to some extent; the urban heat island (UHI area and intensity will increase compared with the current situation; continuous heat islands may occur in local areas; the UHI potential index of the core area will rise from 0.0878 to 0.1217 (still a favorable level. Therefore, urban surfaces should be carefully developed and arranged during planning. It is suggested that the negative impacts of large areas of urban construction on the local climatic environment in the Yanqi Lake could be mitigated by 1 strengthening the airflow by introducing fresh, cold, northwesterly air via constructed ventilation corridors, 2 increasing the number of ecological cold sources, particularly for water bodies and green belts to prevent the UHI in the southern region of Yanqi Lake from becoming linked with each other, and 3 considering a

  1. Assessing coupling between lakes and layered aquifers in a complex Pleistocene landscape based on water level dynamics (United States)

    Lischeid, Gunnar; Natkhin, Marco; Steidl, Jörg; Dietrich, Ottfried; Dannowski, Ralf; Merz, Christoph


    The biosphere reserve Schorfheide-Chorin is a scenic region with many lakes. Hydraulic coupling between lakes and groundwater is difficult to assess due to the very heterogeneous Pleistocene deposits with a complex layering of different aquifers, part of them being confined. Thus, a principal component analysis of time series of groundwater and lake water levels was performed. The first two principal components provided a quantitative measure of damping of the input signal, i.e., the extent to which time series of groundwater pressure heads or lake water levels are smoothed and delayed with respect to the input signal, i.e., groundwater recharge or precipitation minus evapotranspiration, respectively. The lakes differed substantially with respect to damping behaviour, indicating different impacts of deep groundwater contribution. For most of the groundwater wells, damping increased linearly with mean depth to water table. In contrast, some wells exhibited nearly identical behaviour independent of depth. High-pass filtered data of water table level from these wells were strongly and inversely correlated with those of barometric pressure fluctuations, pointing to a confined aquifer which was evidently not connected to the adjacent lake.

  2. Stable isotope assessment of water quality, primary productivity, nutrient sources, and food web structure in Lake Winnipeg (United States)

    Wassenaar, L. I.


    Lake Winnipeg (Canada) is a shallow great lake currently undergoing extensive eutrophication. A 4-year stable isotope project is currently underway to examine water quality, primary productivity, nutrient sources, and food web structure in the lake. The isotope hydrology (18O, 2H) of Lake Winnipeg is needed in order to gain a picture of spatial isotopic patterns in the lake that can be related to the unique fingerprints imposed by contributing watersheds, and to verify hydrodynmamic mixing models. Stable isotope assays of key nutrients (nitrate, phosphate), particulate organic matter (POM), and dissolved oxygen in Lake Winnipeg are being applied to assess (1) the sources of nutrients, (2) the sources of the organic matter (internal vs external), (3) the biogeochemical cycling of nutrients and organic matter that lead to algal formation and enhanced biological oxygen demand and 4) quantify the rates of aquatic photoautotrophic activity, respiration and gas exchange. Altogether, these assays will allow us to better link nutrient sources and cycling to enhanced aquatic productivity. Foodweb structure and function is being examined using 13C and 15N while DH and 34S are being evaluated as tracer of inter basin fish migration. Only if the current foodweb structure is well understood can predictions regarding the negative impacts of eutrophication and invasive species on the foodweb be possible.

  3. A reappraisal of some Cigar Lake issues of importance to performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Smellie, J. [Conterra AB (Sweden); Karlsson, Fred [Swedish Nucelear Fuel and Waste Management Co., Stockholm (Sweden)


    The AECL/SKB Cigar Lake Analogue Study was published in 1994. Data from this study, relevant for repository performance assessments, have been reappraised in the light of greater exposure to analogue studies and the development of more realistic models used in performance assessment. Several of the areas proved to have been adequately addressed in the original study, but one of the areas that particularly benefited from the renewed analysis concerned radiolysis. In this case a model for radiolysis was developed and tested, significantly narrowing the gap between calculated and predicted oxidant production. Considerable progress was also made in understanding and modelling the initial formation of the deposit under hydrothermal conditions, and using this conceptual model to evaluate the changes that have subsequently occurred under `ambient` repository conditions over geological timescales. Moreover, the physical properties of clay as a potential buffer to groundwater flow and radionuclide migration were addressed with some success. 99 refs.

  4. Seismic Risk Assessment of Urban and Rural Settlements around Lake Malawi

    Directory of Open Access Journals (Sweden)

    Katsuichiro Goda


    Full Text Available The seismic risk potential for Malawi is high because traditional adobe and earthen structures are seismically vulnerable and large earthquakes of Mw7.0 or greater can be originated from the Malawi Rift. To assess seismic risk of the Malawian communities quantitatively, data and models for exposure, hazard, and vulnerability modules that are suitable for Malawi are integrated. The developed risk model is applied to a retrospective appraisal of the past damaging 2009 Karonga earthquake sequence and to the future earthquake scenarios for long-term risk management purposes. The earthquake impact assessment results highlight that the collapse risk predictions of the Malawian settlements are particularly dependent on the inclusion of large-magnitude earthquakes from the active faults around Lake Malawi and the selection and combination of seismic vulnerability models.

  5. Spatial Variation, Pollution Assessment and Source Identification of Major Nutrients in Surface Sediments of Nansi Lake, China

    Directory of Open Access Journals (Sweden)

    Longfeng Wang


    Full Text Available Nansi Lake has been seriously affected by intensive anthropogenic activities in recent years. In this study, an extensive survey on spatial variation, pollution assessment as well as the possible sources identification of major nutrients (Total phosphorus: TP, Total nitrogen: TN, and Total organic carbon: TOC in the surface sediments of Nansi Lake was conducted. Results showed that the mean contents of TP, TN and TOC were 1.13-, 5.40- and 2.50- fold higher than their background values respectively. Most of the TN and TOC contents in the surface sediments of Nansi Lake were four times as high or higher and twice as high or higher than the background values except the Zhaoyang sub-lake, and the spatial distribution of TN and TOC contents were remarkably similar over a large area. Nearly all the TP contents in the surface sediments of Nansi Lake were all higher than its background values except most part of the Zhaoyang sub-lake. Based on the enrichment factor (EF and the organic pollution evaluation index (Org-index, TP, TOC and TN showed minor enrichment (1.13, minor enrichment (2.50 and moderately severe enrichment (5.40, respectively, and most part of the Dushan sub-lake and the vicinity of the Weishan island were in moderate or heavy sediments organic pollution, while the other parts were clean. Moreover, according to the results of multivariate statistical analysis, we deduced that anthropogenic TN and TOC were mainly came from industrial sources including enterprises distributed in Jining, Yanzhou and Zoucheng along with iron and steel industries distributed in the southern of the Weishan sub-lake, whereas TP mainly originated from runoff and soil erosion coming from agricultural lands located in Heze city and Weishan island, the local aquacultural activities as well as the domestic sewage discharge of Jining city.

  6. Ecological assessment of Great Lota Lake (Turkey) on the base of ...

    African Journals Online (AJOL)

    The diatoms are very important component for aquatic ecosystems. Turkey has a rich lake potential and many of the lakes have high level of endemism. For this reason, the Great Lota Lake was investigated between October 2000 and October 2001 in sampling periods of approximately per 15 days from one station. Totally ...

  7. Glacial lakes in the Horgos river basin and their outbreak risk assessment

    Directory of Open Access Journals (Sweden)

    A. P. Medeu


    Full Text Available The river Khorgos (in Kazakhstan – Korgas is a boundary river between Kazakhstan and China. Its basin is located in the central part of southern slope of Dzhungarskiy (Zhetysu Alatau range. According to agreement between Kazakhstan and China at the boundary transition of Khorgos in the floodplain of the river Khorgos the large Center of Frontier Cooperation is erected. Estimation of safety of the mentioned object including connection with possible glacial lakes outbursts has the importance of political-economical value. Nowadays development of glacial lakes in the overhead part of Khorgos river basin has reached apogee. As a roof we can mention the maximum of total glacial lakes area (1,7 million m² in 41 lakes and emptied kettles of former glacial lakes. Six lakes reached highly dangerous outburst stage: the volume of lakes reached some million m³, maximum depth up to 30–40 m. Focal ground filtration of the water from lakes takes place. Development of glacial lakes in Khorgos river basin will continue, and these lakes give and will give real danger for the Center of Frontier Cooperation in case of outburst of naturally dammed lake Kazankol with the similar mechanism of Issyk lake outburst, occurred in 1963 in ZailijskiyAlatau (Ile Alatau.

  8. Assessment of Reservoir Water Quality Using Multivariate Statistical Techniques: A Case Study of Qiandao Lake, China

    Directory of Open Access Journals (Sweden)

    Qing Gu


    Full Text Available Qiandao Lake (Xin’an Jiang reservoir plays a significant role in drinking water supply for eastern China, and it is an attractive tourist destination. Three multivariate statistical methods were comprehensively applied to assess the spatial and temporal variations in water quality as well as potential pollution sources in Qiandao Lake. Data sets of nine parameters from 12 monitoring sites during 2010–2013 were obtained for analysis. Cluster analysis (CA was applied to classify the 12 sampling sites into three groups (Groups A, B and C and the 12 monitoring months into two clusters (April-July, and the remaining months. Discriminant analysis (DA identified Secchi disc depth, dissolved oxygen, permanganate index and total phosphorus as the significant variables for distinguishing variations of different years, with 79.9% correct assignments. Dissolved oxygen, pH and chlorophyll-a were determined to discriminate between the two sampling periods classified by CA, with 87.8% correct assignments. For spatial variation, DA identified Secchi disc depth and ammonia nitrogen as the significant discriminating parameters, with 81.6% correct assignments. Principal component analysis (PCA identified organic pollution, nutrient pollution, domestic sewage, and agricultural and surface runoff as the primary pollution sources, explaining 84.58%, 81.61% and 78.68% of the total variance in Groups A, B and C, respectively. These results demonstrate the effectiveness of integrated use of CA, DA and PCA for reservoir water quality evaluation and could assist managers in improving water resources management.

  9. Assessing contamination in Great Lakes sediments using benthic invertebrate communities and the sediment quality triad approach (United States)

    Canfield, Timothy J.; Dwyer, F. James; Fairchild, James F.; Haverland, Pamela S.; Ingersoll, Christopher G.; Kemble, Nile E.; Mount, David R.; La Point, Thomas W.; Burton, G. Allen; Swift, M. C.


    Sediments in many Great Lakes harbors and tributary rivers are contaminated. As part of the USEPA's Assessment and Remediation of Contaminated Sediment (ARCS) program, a number of studies were conducted to determine the nature and extent of sediment contamination in Great Lakes Areas of Concern (AOC). This paper describes the composition of benthic invertebrate communities in contaminated sediments and is one in a series of papers describing studies conducted to evaluate sediment toxicity from three AOC's (Buffalo River, NY; Indiana Harbor, IN; Saginaw River, MI), as part of the ARCS Program. Oligochaeta (worms) and Chironomidae (midge) comprised over 90% of the benthic invertebrate numbers in samples collected from depositional areas. Worms and midge consisted of taxa identified as primarily contaminant tolerant organisms. Structural deformities of mouthparts in midge larvae were pronounced in many of the samples. Good concurrence was evident between measures of laboratory toxicity, sediment contaminant concentration, and benthic invertebrate community composition in extremely contaminated samples. However, in moderately contaminated samples, less concordance was observed between the benthos community composition and either laboratory toxicity test results or sediment contaminant concentration. Laboratory sediment toxicity tests may better identify chemical contamination in sediments than many commonly used measures of benthic invertebrate community composition. Benthic measures may also reflect other factors such as habitat alteration. Evaluation of non-contaminant factors are needed to better interpret the response of benthic invertebrates to sediment contamination.

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

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    Nathan Torbick


    Full Text Available 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.

  11. Hazard Assessment of Glacial Lake Outburst Flood and Potential of ICTs for Coping: A Case of Eastern Himalaya of Nepal (United States)

    Bhattarai, D. R.


    Retreat of glaciers and formation of glacial lakes in Nepal Himalaya have been reported to be related with the temperature rise in the region. Glacier Lake Outburst Floods (GLOF) are the growing climate induced hazards in the Himalaya. GLOF has increased the vulnerability of community and fragile ecosystem in the mountain valleys. This study has analyzed the potential impacts from GLOF in the highland of eastern Nepal and the potential role of Information Communication Technologies (ICT) to cope with such impacts. I analyzed the trend of climatic pattern (temperature and precipitation) of the Eastern Himalaya Region of Nepal available from the Department of Hydrology and Meteorology, Government of Nepal, and prepared the latest location map of the glacial lakes using google earth and ArcGIS applications in the highland of the Kanchanjungha Conservation Area of the region. Tiptala glacial lake, located at an elevation of 4950 m, within the conservation area, was selected for the GLOF hazard assessment. I used semi-structured questionnaire survey and key informants' interviews in the community in order to assess the potential hazard of GLOF. With the varying sizes, 46 glacial lakes were located in the region, which covers over 2.57 sq. km in total. Though the larger portion of the downstream area of the Tiptala glacial lake fall in the remote location away from major residential area, few villages, major pasture lands for Yaks, foot trails, and several bridges across the Tamor River below the lake are in risk of GLOF. Poor access due to extreme geographical remoteness and capacity to afford the modern technologies in the community are the major limiting factor to the knowledge and information about the climate change and related impacts. Modern ICTs has high potential to reduce the risk of climate related hazards in the remote area by information dissemination and awareness.

  12. Detection of microcystins in Pamvotis lake water and assessment of cyanobacterial bloom toxicity. (United States)

    Papadimitriou, Theodoti; Armeni, Euthimia; Stalikas, Constantine D; Kagalou, Ifigeneia; Leonardos, Ioannis D


    Lake Pamvotis is a shallow, eutrophic Mediterranean lake with ecological significance. This paper deals with the evaluation of cyanobacterial toxicity in Lake Pamvotis. ELISA and HPLC revealed the presence of significant amounts of MCYST-LR. Danio rerio bioassay confirmed the toxic nature of the bloom. Cyanobacterial extracts had adverse toxic effects on development of D. rerio. Also, it was shown that cyanobacterial extracts containing environmentally detected concentrations of MCYST can cause reduced survival rate of fish species. The results clearly indicate that cyanobacterial blooms in Lake Pamvotis may be regarded as human and fish health hazard. Continuous monitoring of the lake is suggested, in order to prevent future possible intoxications.

  13. Integrated satellite InSAR and slope stability modeling to support hazard assessment at the Safuna Alta glacial lake, Peru (United States)

    Cochachin, Alejo; Frey, Holger; Huggel, Christian; Strozzi, Tazio; Büechi, Emanuel; Cui, Fanpeng; Flores, Andrés; Saito, Carlos


    The Safuna glacial lakes (77˚ 37' W, 08˚ 50' S) are located in the headwater of the Tayapampa catchment, in the northernmost part of the Cordillera Blanca, Peru. The upper lake, Laguna Safuna Alta at 4354 m asl has formed in the 1960s behind a terminal moraine of the retreating Pucajirca Glacier, named after the peak south of the lakes. Safuna Alta currently has a volume of 15 x 106 m3. In 2002 a rock fall of several million m3 from the proximal left lateral moraine hit the Safuna Alta lake and triggered an impact wave which overtopped the moraine dam and passed into the lower lake, Laguna Safuna Baja, which absorbed most of the outburst flood from the upper lake, but nevertheless causing loss in cattle, degradation of agricultural land downstream and damages to a hydroelectric power station in Quitaracsa gorge. Event reconstructions showed that the impact wave in the Safuna Alta lake had a runup height of 100 m or more, and weakened the moraine dam of Safuna Alta. This fact, in combination with the large lake volumes and the continued possibility for landslides from the left proximal moraine pose a considerable risk for the downstream settlements as well as the recently completed Quitaracsa hydroelectric power plant. In the framework of a project funded by the European Space Agency (ESA), the hazard situation at the Safuna Alta lake is assessed by a combination of satellite radar data analysis, field investigations, and slope stability modeling. Interferometric analyses of the Synthetic Aperture Radar (InSAR) of ALOS-1 Palsar-1, ALOS-2 Palsar-2 and Sentinel-1 data from 2016 reveal terrain displacements of 2 cm y-1 in the detachment zone of the 2002 rock avalanche. More detailed insights into the characteristics of these terrain deformations are gained by repeat surveys with differential GPS (DGPS) and tachymetric measurements. A drone flight provides the information for the generation of a high-resolution digital elevation model (DEM), which is used for the

  14. How to Assess Trajectories of Arctic Ponds and Lakes: a Circum-Arctic Perspective (United States)

    Muster, S.; Roth, K.; Cresto Aleina, F.; Langer, M.; Bartsch, A.; Morgenstern, A.; Grosse, G.; Lange, S.; Boike, J.


    Arctic ponds, i. e. water bodies with a surface area equal to or smaller than 10⁴ m² (1 ha), are currently not inventoried on a circum-arctic scale. However, they are a key element of the water, energy, and carbon balance and abundant in Arctic permafrost lowlands. Ponds and lakes have been subject to both wetting and drying in a warming climate yet studies remain ambivalent regarding the causes of these changes. Goals of this study are to (i) investigate the variability of water body size distributions as a function of landscape characteristics, and (ii) assess the vulnerability of water bodies in different landscapes to scenarios of wetting and drying. Ponds and lakes were mapped from high-resolution aerial and satellite imagery with resolutions of 4 m or better in 14 regions in Alaska, Canada, and Siberia covering a total area of ca. 1.6*104 km². Whereas lake distributions are similar, pond distributions in our study regions vary significantly with the area-normalized number of ponds differing up to 3 orders of magnitude. Landscape characteristics that may explain the current water body distributions include climate (eg., precipitation, evapotranspiration, temperature), permafrost (eg., ground ice content, maximum thaw depth) and terrain characteristics (eg., topography, glaciation, landscape age) which we derive from in situ, remote sensing and modeling data sources. Multivariate regression analysis are used to relate landscape characteristics to distribution parameters. This study for the first time allows to quantify the circum-arctic variability of pond distribution. The current maps are the start of a high-resolution circum-arctic water body inventory and present a baseline for future surface inundation mapping and modelling. We present representative regional probability density functions (pdf) and assess the potential to upscale pdfs using spatial landscape characteristics. We then discuss the vulnerability of water bodies to wetting or drying based

  15. The Status of School Psychology in Ontario School Boards: 2016 Perspective (United States)

    Lean, Debra


    This article reports on the status of school psychology in Ontario. School psychology practice in Ontario has continued to evolve since the previous report was published in 2001. School psychologists have varied roles, and although the most prominent one remains as assessing students for entry into certain special education services, school-based…

  16. Integration of Classification Tree Analyses and Spatial Metrics to Assess Changes in Supraglacial Lakes in the Karakoram Himalaya (United States)

    Bulley, H. N.; Bishop, M. P.; Shroder, J. F.; Haritashya, U. K.


    Alpine glacier responses to climate chnage reveal increases in retreat with corresponding increases in production of glacier melt water and development of supraglacial lakes. The rate of occurrence and spatial extent of lakes in the Himalaya are difficult to determine because current spectral-based image analysis of glacier surfaces are limited through anisotropic reflectance and lack of high quality digital elevation models. Additionally, the limitations of multivariate classification algorithms to adequately segregate glacier features in satellite imagery have led to an increased interest in non-parametric methods, such as classification and regression trees. Our objectives are to demonstrate the utility of a semi-automated approach that integrates classification- tree-based image segmentation and object-oriented analysis to differentiate supraglacial lakes from glacier debris, ice cliffs, lateral and medial moraines. The classification-tree process involves a binary, recursive, partitioning non-parametric method that can account for non-linear relationships. We used 2002 and 2004 ASTER VNIR and SWIR imagery to assess the Baltoro Glacier in the Karakoram Himalaya. Other input variables include the normalized difference water index (NDWI), ratio images, Moran's I image, and fractal dimension. The classification tree was used to generate initial image segments and it was particularly effective in differentiating glacier features. The object-oriented analysis included the use of shape and spatial metrics to refine the classification-tree output. Classification-tree results show that NDWI is the most important single variable for characterizing the glacier-surface features, followed by NIR/IR ratio, IR band, and IR/Red ratio variables. Lake features extracted from both images show there were 142 lakes in 2002 as compared to 188 lakes in 2004. In general, there was a significant increase in planimetric area from 2002 to 2004, and we documented the formation of 46 new

  17. Assessing the hydrological impacts of agricultural changes upstream of the Tunisian World Heritage sea-connected Ichkeul Lake

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    J. Aouissi


    Full Text Available The impact of changes in agricultural land use and practices as a controlling driver of hydrologic response and as a source of diffuse pollution, are studied in the Joumine River basin, discharging into the Ichkeul Lake, northern Tunisia, a UNESCO World Heritage site since 1979. The lake is characterized by a very specific hydrological functioning based on a seasonal alternation of water levels and salinity through its link to the Mediterranean Sea. Three Landsat images, in situ surveys and SWAT modelling were used to simulate and assess streamflows and nitrate loads under retrospective land uses.

  18. Assessment of metals distribution and microbial contamination at selected lake waters in and around Miri City, East Malaysia. (United States)

    Prasanna, M V; Nagarajan, R; Chidambaram, S; Elayaraja, A


    A baseline study was carried out to assess the metal concentrations and microbial contamination at selected Lake waters in and around Miri City, East Malaysia. Sixteen surface water samples were collected at specific Lakes in the environs of major settlement areas and recreational centers in Miri City. The Physico-chemical parameters [pH, Electrical Conductivity (EC) and Dissolved Oxygen (DO)], metals (Fe, Mn, Cu, Cd, Ni and Zn) and Escherichia coli (E. coli) were analysed. The concentrations of Fe, Mn and Ni have been found to be above the permissible limits of drinking water quality standards. The metals data have also been used for the calculation of heavy metal pollution index. Higher values of E. coli indicate microbial contamination in the Lake waters.

  19. Performance of ASTER and SRTM DEMs, and their potential for assessing glacial lakes in the Lunana region, Bhutan Himalaya (United States)

    Fujita, Koji; Suzuki, Ryohei; Nuimura, Takayuki; Sakai, Akiko

    To assess the potential volume of a glacial lake outburst flood (GLOF) more precisely than in previous studies, we analyze ground survey data and remote-sensing digital elevation models (DEMs) around glacial lakes in the Lunana region, Bhutan. Based on a DEM generated from differential GPS ground surveys, we first evaluate the relative accuracies of DEMs produced by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM). Root-mean-square errors of the altitudinal difference between these DEMs and ground survey data were 11.0 m for ASTER and 11.3 m for SRTM. These errors are similar to those of previous studies. We show that a topographical classification allows a better estimate of elevation on lakes/ponds, riverbeds and glaciers due to their flat surfaces, while the relative accuracy is worse over moraines and hill slopes due to their narrow ridges and steep slopes. Using the optical satellite images and the ground survey data, we re-evaluate the GLOF volume in 1994 as (17.2±5.3) × 106 m3. We show GLOF-related information such as distance, altitudinal difference and gradient at possible outburst points where the lake level is higher than the neighboring riverbed and/or glacial lake.

  20. Using of zooplankton indicators in assessing the quality of waters in two lakes in the Gulf of Finland basin

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    Kulakov Dmitry


    Full Text Available In 2012–2015 zooplankton studies were carried out and the quality of the waters of the Kopanskoe and the Gorovaldayskoe lakes belonging to the Gulf of Finland basin (Leningrad region was assessed. Under the frame of long-term monitoring studies on these waterbodies, such work has not previously been carried out. The sampling stations were located in the coastal part of the waterbodies. Zooplankton of the lakes included 46 taxons of species and subspecies ranks, it was typical of the North-West of Russia and represented mainly by eurybiontic species with high ecological plasticity. In Gorovaldayskoe lake most affected by the anthropogenic influence, in comparison with the Kopanskoe, showed the lowest species richness and the lowest values of the biodiversity index. Nevertheless, the mass development of Cladocera, which made the main contribution to the population and the biomass of the community, promoted the active development of the processes of biological self-purification of this lake, as evidenced by a decrease by coefficient trophicity. According to the saprobity index in the waters of the studied lakes belonged to the oligosaprobic – β-mesosaprobic zone.

  1. A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

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    G. Kostoski


    Full Text Available Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact.

    Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes.

    Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1 assess threats to Lake Ohrids' (endemic biodiversity, (2 summarize existing conservation activities and strategies, and (3 outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1 watershed impacts, (2 agriculture and forestry, (3 tourism and population growth, (4 non-indigenous species, (5 habitat alteration or loss, (6 unsustainable exploitation of fisheries, and (7 global climate change.

    Among the major (well-known threats with high impact are nutrient input (particularly of phosphorus, habitat conversion and silt load. Other threats are potentially of high impact but less well known. Such threats include pollution with hazardous substances (from sources such as mines, former industries, agriculture or climate change. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species

  2. Water Availability and Use Pilot-A multiscale assessment in the U.S. Great Lakes Basin (United States)

    Reeves, Howard W.


    Beginning in 2005, water availability and use were assessed for the U.S. part of the Great Lakes Basin through the Great Lakes Basin Pilot of a U.S. Geological Survey (USGS) national assessment of water availability and use. The goals of a national assessment of water availability and use are to clarify our understanding of water-availability status and trends and improve our ability to forecast the balance between water supply and demand for future economic and environmental uses. This report outlines possible approaches for full-scale implementation of such an assessment. As such, the focus of this study was on collecting, compiling, and analyzing a wide variety of data to define the storage and dynamics of water resources and quantify the human demands on water in the Great Lakes region. The study focused on multiple spatial and temporal scales to highlight not only the abundant regional availability of water but also the potential for local shortages or conflicts over water. Regional studies provided a framework for understanding water resources in the basin. Subregional studies directed attention to varied aspects of the water-resources system that would have been difficult to assess for the whole region because of either data limitations or time limitations for the project. The study of local issues and concerns was motivated by regional discussions that led to recent legislative action between the Great Lakes States and regional cooperation with the Canadian Great Lakes Provinces. The multiscale nature of the study findings challenges water-resource managers and the public to think about regional water resources in an integrated way and to understand how future changes to the system-driven by human uses, climate variability, or land-use change-may be accommodated by informed water-resources management.

  3. The Lake Bosumtwi impact structure in Ghana: A brief environmental assessment and discussion of ecotourism potential (United States)

    Boamah, Daniel; Koeberl, Christian

    Lake Bosumtwi is a natural inland freshwater lake that originated from a meteorite impact. The lake is becoming a popular tourist attraction in Ghana and has the potential to be developed as an ecotourism site in the future. However, there have been some unregulated human activities and unplanned infrastructure development, and there are increased levels of pollutants in the lake water. In order to make ecotourism at Lake Bosumtwi successful in the long term, the Lake Bosumtwi Development Committee has been formed to ensure that local people are empowered to mobilize their own capacities. It has been realized that an important criterion required to develop ecotourism in a socially responsible, economically efficient, and environmentally viable way is to foster a constructive dialogue between the local people and tourists about the needs of the indigenous people.

  4. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data (United States)

    Velpuri, N. M.; Senay, G. B.


    along the Lake Turkana shoreline that are vulnerable to fluctuations in lake levels due to the Gibe III dam were also identified. This study demonstrates the effectiveness of using existing multi-source satellite data in a basic modeling framework to assess the potential hydrological impact of an upstream dam on a terminal downstream lake. The results obtained from this study could also be used to evaluate alternative dam-filling scenarios and assess the potential impact of the dam on Lake Turkana under different operational strategies.

  5. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data

    Directory of Open Access Journals (Sweden)

    N. M. Velpuri


    dam commencement. Areas along the Lake Turkana shoreline that are vulnerable to fluctuations in lake levels due to the Gibe III dam were also identified. This study demonstrates the effectiveness of using existing multi-source satellite data in a basic modeling framework to assess the potential hydrological impact of an upstream dam on a terminal downstream lake. The results obtained from this study could also be used to evaluate alternative dam-filling scenarios and assess the potential impact of the dam on Lake Turkana under different operational strategies.

  6. Simulation and assessment of groundwater flow and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2003 through 2013: Chapter B of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015 (United States)

    Jones, Perry M.; Roth, Jason L.; Trost, Jared J.; Christenson, Catherine A.; Diekoff, Aliesha L.; Erickson, Melinda L.


    Water levels during 2003 through 2013 were less than mean water levels for the period 1925–2013 for several lakes in the northeast Twin Cities Metropolitan Area in Minnesota. Previous periods of low lake-water levels generally were correlated with periods with less than mean precipitation. Increases in groundwater withdrawals and land-use changes have brought into question whether or not recent (2003–13) lake-water-level declines are solely caused by decreases in precipitation. A thorough understanding of groundwater and surface-water exchanges was needed to assess the effect of water-management decisions on lake-water levels. To address this need, the U.S. Geological Survey, in cooperation with the Metropolitan Council and the Minnesota Department of Health, developed and calibrated a three-dimensional, steady-state groundwater-flow model representing 2003–13 mean hydrologic conditions to assess groundwater and lake-water exchanges, and the effects of groundwater withdrawals and precipitation on water levels of 96 lakes in the northeast Twin Cities Metropolitan Area.Lake-water budgets for the calibrated groundwater-flow model indicated that groundwater is flowing into lakes in the northeast Twin Cities Metropolitan Area and lakes are providing water to underlying aquifers. Lake-water outflow to the simulated groundwater system was a major outflow component for Big Marine Lake, Lake Elmo, Snail Lake, and White Bear Lake, accounting for 45 to 64 percent of the total outflows from the lakes. Evaporation and transpiration from the lake surface ranged from 19 to 52 percent of the total outflow from the four lakes. Groundwater withdrawals and precipitation were varied from the 2003‒13 mean values used in the calibrated model (30-percent changes in groundwater withdrawals and 5-percent changes in precipitation) for hypothetical scenarios to assess the effects of groundwater withdrawals and precipitation on water budgets and levels in Big Marine Lake, Snail Lake

  7. Monitoring and Assessment of Hydrological and Ecological Changes in Lake Manyas (United States)

    Curebal, Isa; Efe, Recep; Soykan, Abdullah; Sonmez, Suleyman


    Manyas Lake in the northwest of Turkey occupies an area of 165 square kilometers. The surface area of the lake is continuously changing due to human activities, hydrologic and climatic conditions. The objective of this study is to examine the changes in water level and the area of lake and the effects of these changes on the lake's ecosystem and human economic activities. In order to determine the changes lake level measurement data, 1/25000 scale topography maps, rainfall and temperature data and bathymetry maps were used and elevation models were made. During the study period the water level fluctuated between 14.0 and 17.8 meters, and surface area changed between 124,8 km2 and 170,6 km2 respectively. Prior to the construction of a flood barrier at the southern end of the lake in 1992 the maximum surface area of the lake was calculated at 209 km2. Lake Manyas is an important wetland on the route of migration of birds from/to Europe and Africa. 64 ha of the lake and its surroundings along with the entire National Park is a Ramsar site. Irrigated and dry farming is practiced around the lake and fishing is important economic activity. The changes in the water level as result of natural and human factors brought about negative effects on the lake's ecosystem in last ten years. Result of these effects, natural fluctuation of the lake changed and the marshes around the lake destroyed and the bird population decreased. Lowering the water level in the lake is also significantly reduced the number of fish and number of migratory birds. The construction of the flood barrier destroyed vegetation and bird life in about a 25% of area of the lake on the south. The natural ecosystem in this area has been adversely affected. Moreover, when the water level is low due to low rain fall and irrigation, vegetation on the lake's shore line dies and some areas turn to swamp. The fauna and flora are negatively affected by water level changes particularly in the protected National Park

  8. Hepatitis Delta Infections in Toronto, Ontario


    S. Victor Feinman; Barnet Berris; John L. Gerin; Robert H. Purcell


    This study assessed the prevalence of hepatitis delta virus infection, the relation of this infection to the clinical and histological status and to the geographic origin of 216 patients with hepatitis B virus infection in Toronto, Ontario. Evidence of delta infection was present in 13 of the 216 patients (6.0%). It was more common in patients with acute hepatitis (11.1%) and with chronic hepatitis (16.7%) than in asymptomatic carriers (3.6%). It was not present in the three patients with hep...

  9. Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA (United States)

    Rosen, Michael R.; Van Metre, P.C.


    Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

  10. Transmission system planning in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Barrie, D.; Macedo, F.X.; Mcconnach, J.S. [Ontario Hydro, Toronto, ON (Canada)


    In recent years, new and modified approaches to planning the large transmission system that serves the province of Ontario, Canada, have been necessary to accommodate the rapidly changing planning environment including slower uncertain growth, ageing of facilities, integration of demand side management and non utility generation options, increased competitiveness, increased financial stresses and affordable constraints. This paper describes some of the new and modified approaches and tools that have been adopted or are being developed by Ontario Hydro to cope with this changing environment. (author) 9 refs., 4 figs.

  11. Genetic Diversity of Picocyanobacteria in Tibetan Lakes: Assessing the Endemic and Universal Distributions (United States)

    Hu, Anyi; Liu, Xiaobo; Chen, Feng; Yao, Tandong; Jiao, Nianzhi


    The phylogenetic diversity of picocyanobacteria in seven alkaline lakes on the Tibetan Plateau was analyzed using the molecular marker 16S-23S rRNA internal transcribed spacer sequence. A total of 1,077 environmental sequences retrieved from the seven lakes were grouped into seven picocyanobacterial clusters, with two clusters newly described here. Each of the lakes was dominated by only one or two clusters, while different lakes could have disparate communities, suggesting low alpha diversity but high beta diversity of picocyanobacteria in these high-altitude freshwater and saline lakes. Several globally distributed clusters were found in these Tibetan lakes, such as subalpine cluster I and the Cyanobium gracile cluster. Although other clusters likely exhibit geographic restriction to the plateau temporally, reflecting endemicity, they can indeed be distributed widely on the plateau. Lakes with similar salinities may have similar genetic populations despite a large geographic distance. Canonical correspondence analysis identified salinity as the only environmental factor that may in part explain the diversity variations among lakes. Mantel tests suggested that the community similarities among lakes are independent of geographic distance. A portion of the picocyanobacterial clusters appear to be restricted to a narrow salinity range, while others are likely adapted to a broad range. A seasonal survey of Lake Namucuo across 3 years did not show season-related variations in diversity, and depth-related population partitioning was observed along a vertical profile of the lake. Our study emphasizes the high dispersive potential of picocyanobacteria and suggests that the regional distribution may result from adaptation to specified environments. PMID:25281375

  12. Reforming Ontario Early Learning: A Review (United States)

    Ryan, Thomas; Date, Gavin


    Herein, we address the reformation of Ontario early learning. Over the next 3 years, all 4- and 5-year-olds in Ontario (Canada) will be able to attend full-day early learning with child care, before and after school provided by the Government of Ontario Ministry of Education. The benefits of such a change are both academic and societal and are…

  13. Acidification and recovery at mountain lakes in Central Alps assessed by the MAGIC model

    Directory of Open Access Journals (Sweden)

    Michela ROGORA


    Full Text Available The dynamic model MAGIC was calibrated and applied to 84 lakes in Central Alps to predict the response of water chemistry to different scenarios of atmospheric deposition of S and N compounds. Selected lakes were representative of a wide range of chemical characteristics and of sensitivity to acidification. The most sensitive lakes have already shown in the latest years signs of recovery in terms of pH and ANC. The model well captured the main trends in lake chemical data. According to the model forecast, recovery at sensitive lakes will continue in the next decades under the hypothesis of a further decrease of acidic input from the atmosphere. Results clearly demonstrated the benefits of achieving the emission reductions in both S and N compounds agreed under the Gothenburg Protocol. Nevertheless, besides the achieved reduction of SO4 2- deposition from the peak levels of the 80s, also N deposition should be reduced in the near future to protect alpine lakes from further acidification. The condition of lake catchments with regard to N saturation will probably be the dominant factor driving recovery extent. Beside atmospheric deposition, other factors proved to be important in determining long-term changes in surface water chemistry. Climate warming in particular affects weathering processes in lake catchments and dynamics of the N cycle. Including other factors specific to the alpine area, such as dust deposition and climate change, may improve the fit of experimental data by the model and the reliability of model forecast.

  14. Environmental Assessment for Lake Ashtabula Winter Drawdown, Barnes County, North Dakota (United States)


    not been surveyed in detail. Common species include sago pondweed, clasping leaf pondweed, northern Lake Ashtabula Winter Drawdown, Environmental...vegetation (Peterka 1972). Sago pondweed attracts waterfowl, which feed on the plant. 2.5 CULTURAL RESOURCES Cultural resources in the Lake...dewatering. In summers following these low drawdowns, the sago pondweed beds are smaller, especially near the Karnak Wildlife Management Area. The

  15. Assessment of cyanobacteria toxins in freshwater fish: a case study of Murchison Bay (Lake Victoria) and Lake Mburo, Uganda. (United States)

    Nyakairu, George William Atwoki; Nagawa, Christine Betty; Mbabazi, Jolocam


    There is little information on the distribution of microcystins (MCs) in Oreochromis niloticus (ON) and Lates niloticus (LN) obtained from L. Mburo and Murchison Bay of L. Victoria. These fishes are harvested and sold both for local human consumption and for export. The presence of MC-RR, MC-LR and MC-YR in different organs (gut, muscle and liver) was determined using Liquid Chromatography coupled with a Mass Spectrometry Detector (LC/MS/MS). The total MCs in ON gut, muscle and liver were 1312.08, 208.65 and 73.10 ng g(-1) from L. Mburo and 1479.24, 9.65 and 48.07 ng g(-1) from Murchison Bay, respectively, while for LN from Murchison Bay they were 27.78, 1.86 and 3.74 ng g(-1). Generally, in both lakes, MC-RR was the most dominant followed by MC-YR and MC-LR, respectively. Gut showed a high MC content, followed by liver and muscle, in that order. The presence of MCs in muscle indicated possible fish contamination, which implied that it was possible to transfer the toxins to humans who are at the end of the food chain. This poses a risk to them since the MCs are heat stable. The local authorities should warn the public of the risk of possible poisoning by eating the contaminated fish. Copyright 2009 Elsevier Ltd. All rights reserved.

  16. Preliminary Assessment of Cyanobacteria Diversity and Toxic Potential in Ten Freshwater Lakes in Selangor, Malaysia. (United States)

    Sinang, Som Cit; Poh, Keong Bun; Shamsudin, Syakirah; Sinden, Ann


    Toxic cyanobacteria blooms are increasing in magnitude and frequency worldwide. However, this issue has not been adequately addressed in Malaysia. Therefore, this study aims to better understand eutrophication levels, cyanobacteria diversity, and microcystin concentrations in ten Malaysian freshwater lakes. The results revealed that most lakes were eutrophic, with total phosphorus and total chlorophyll-a concentrations ranging from 15 to 4270 µg L(-1) and 1.1 to 903.1 µg L(-1), respectively. Cyanobacteria were detected in all lakes, and identified as Microcystis spp., Planktothrix spp., Phormidium spp., Oscillatoria spp., and Lyngbya spp. Microcystis spp. was the most commonly observed and most abundant cyanobacteria recorded. Semi-quantitative microcystin analysis indicated the presence of microcystin in all lakes. These findings illustrate the potential health risk of cyanobacteria in Malaysia freshwater lakes, thus magnifying the importance of cyanobacteria monitoring and management in Malaysian waterways.

  17. Assessing P status and trophic level of two lakes by speciation of particulate phosphorus forms

    Directory of Open Access Journals (Sweden)

    Thomas HÜBENER


    Full Text Available Seasonal variability of dissolved and particulate P forms was investigated in two lakes in Mecklenburg-Western Pomerania (North-East Germany: the polymictic Lake Bützow and the dimictic Lake Dudinghausen. Both lakes had a different trophic status according to the classic parameter total phosphorus, chlorophyll-a as well as phytoplankton biomass and composition. The aim of the study was to test P compounds and P fractions for characterization of the nutrient status of the phytoplankton, especially Polyphosphates and Phospholipids. The field study shows, that these intracellular reserve compounds in algae can not reflect the different nutrient status of the phytoplankton in the two lakes and is therefore not a more sensitive scale to indicate phosphorus limitation of plankton communities.

  18. Hydrologic Budget Assessment of a Small Forested Lake in Northwestern NJ (United States)

    Kelly, S. A.; Barrett, K. R.; Galster, J. C.; Ophori, D. U.; Flores, D.; Jordan, J. J.; Lutey, A. M.


    Lake Wapalanne is a manmade lake, approximately 5.4 hectares, fed primarily by a small stream, with controlled outflow at a broad-crested weir. Located at the eastern edge of the Appalachian Ridge and Valley physiographic province in northwestern New Jersey, Lake Wapalanne and its watershed lie within a forested landscape, surrounded by 6500 hectares of protected land. The lake's location, small size, simplified inflow and outflow, and minimal external impacts provide a research environment ideal for studying present and future hydrologic lake dynamics. Quantifying the water budget for this small lake improves upon the existing understanding of regional surface water and groundwater interactions. Between July 13th and August 3rd we developed a hydrologic budget for Lake Wapalanne. We quantified precipitation, evapotranspiration, stream inflow and outflow, groundwater seepage, and lake water storage using direct and indirect methods. We installed a weather station to collect precipitation, evapotranspiration, and additional weather data used to calculate evaporation with the Penman-Shuttleworth equation. To develop a rating record between water depth and stream discharge, we installed water level loggers at the inlet and outlet streams and within the lake. To determine inlet and outlet discharge rates we used the midpoint method at 60% depth to measure velocity; we used a broad-crested weir equation to verify the outlet stream discharge. We measured groundwater using seepage meters and piezometers installed at various locations in the lake. To determine changes in lake water storage, we completed a bathymetry survey using a total station and used ArcGIS spatial analyst software to create relationships between depth, area, and volume. The water budget was computed in Excel with all variables quantified on a 15-minute interval. Our initial results indicate that the average total precipitation and evapotranspiration were 0.2 cm/day and 0.4 cm/day respectively. For a

  19. Concentrations and human health risk assessment of organochlorine pesticides in edible fish species from a Rift Valley lake-Lake Ziway, Ethiopia. (United States)

    Yohannes, Yared B; Ikenaka, Yoshinori; Saengtienchai, Aksorn; Watanabe, Kensuke P; Nakayama, Shouta M M; Ishizuka, Mayumi


    Fish consumption is known to have several health benefits for humans. However, the accumulation of organic pollutants, like organochlorine pesticides (OCPs) could pose health hazards. Thus, OCPs in edible fish species (Oreochromis niloticus, Tilapia zillii, Carassius spp., and Clarias gariepinus) from Lake Ziway, an Ethiopian Rift Valley Lake were investigated to assess the potential human health hazards of these contaminants. Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, and heptachlors were observed with ΣOCPs concentration ranging from 1.41 to 63.8 ng g(-1) ww. DDTs were the predominant contaminants (0.9 to 61.9 ng g(-1) ww), followed by HCHs. The predominance of DDTs may be attributed to their current use in vector control and contamination from past usage. The estimated daily intakes (EDIs) of OCPs from all fish species were much lower than the acceptable daily intakes (ADIs), indicating that consumption of fish is at little risk to human health at present. However, the cancer risk estimates in the area of concern and the hazard ratios (HRs) of HCHs, DDTs, and heptachlors exceeded the threshold value of one, indicating daily exposure to these compounds is a potential concern. This may result in a lifetime cancer risk greater than of 1 in 10(6). Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007 (United States)

    Loftin, Keith A.; Graham, Jennifer L.; Elizabeth Hilborn,; Sarah Lehmann,; Meyer, Michael T.; Dietze, Julie E.; Griffith, Christopher


    A large nation-wide survey of cyanotoxins (1161 lakes) in the United States (U.S.) was conducted during the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, microcystins, and saxitoxins were detected (ELISA) in 4.0, 32, and 7.7% of samples with mean concentrations of 0.56, 3.0, and 0.061 mg/L, respectively (detections only). Co-occurrence of the three cyanotoxin classes was rare (0.32%) when at least one toxin was detected. Cyanobacteria were present and dominant in 98 and 76% of samples, respectively. Potential anatoxin-, cylindrospermopsin-, microcystin-, and saxitoxin-producing cyanobacteria occurred in 81, 67, 95, and 79% of samples, respectively. Anatoxin-a and nodularin-R were detected (LC/MS/MS) in 15 and 3.7% samples (n = 27). The WHO moderate and high risk thresholds for microcystins, cyanobacteria abundance, and total chlorophyll were exceeded in 1.1, 27, and 44% of samples, respectively. Complete agreement by all three WHO microcystin metrics occurred in 27% of samples. This suggests that WHO microcystin metrics based on total chlorophyll and cyanobacterial abundance can overestimate microcystin risk when compared to WHO microcystin thresholds. The lack of parity among the WHO thresholds was expected since chlorophyll is common amongst all phytoplankton and not all cyanobacteria produce microcystins.

  1. Ontario Science Education Report Card. Canadian National Comparisons. Research Brief. (United States)

    Connelly, F. Michael

    Canada is one of nearly 40 countries involved in the Second International Science Study (SISS). The Ontario Ministry of Education used the data generated in the study as a vehicle for assessing science education in the province, and comparing the province to the rest of Canada. Each chapter of this report contains a non-technical summary of…

  2. Palaeolimnological assessment of the reference conditions and ecological status of lakes in Estonia - implications for the European Union Water Framework Directive

    Directory of Open Access Journals (Sweden)

    Heinsalu, Atko


    Full Text Available The European Union Water Framework Directive (WFD requires an assessment of reference conditions for lakes, i.e. the conditions expected with only minimal human impact on water bodies. Limnological monitoring records seldom go back more than a few decades and so rarely document the onset of human impact on lakes. Methods of palaeolimnological approaches especially fitted for the purposes of the WFD are described and two case studies, on lakes Rõuge Tõugjärv and Pappjärv, are presented. The palaeolimnological study of Rõuge Tõugjärv demonstrated that a commonly held belief that man-made eutrophication of Estonian lakes is a relatively modern matter of concern and is related to post-industrial population growth and intensification of agriculture is a misconception. The lakes, particularly those in rich soil areas, have been mediated by human impact over millennial time-scales. In many European countries it has been agreed that AD 1850 approximately represents the reference conditions for lakes. Our observations in Rõuge Tõugjärv showed that during that period anthropogenic disturbance on the lake was the greatest. Lake Pappjärv is an example of recent human influence on the aquatic ecosystem that has undergone severe degradation due to infiltration into the ground of a variety of substances from the local bitumen plant, mineral fertilizer storage tanks, and road service sand and salt mixing-grounds that have been accumulating in the lake since the 1950s.

  3. Paleolimnological assessment of nutrient enrichment on diatom assemblages in a priori defined nitrogen- and phosphorus-limited lakes downwind of the Athabasca Oil Sands, Canada

    Directory of Open Access Journals (Sweden)

    Kathleen R. Laird


    Full Text Available As the industrial footprint of the Athabasca Oil Sands Region (AOSR continues to expand, concern about the potential impacts of pollutants on the surrounding terrestrial and aquatic ecosystems need to be assessed. An emerging issue is whether recent increases in lake production downwind of the development can be linked to AOSR activities, and/or whether changing climatic conditions are influencing lake nutrient status. To decipher the importance of pollutants, particularly atmospheric deposition of reactive nitrogen (Nr, and the effects of climate change as potential sources of increasing lake production, lakes from both within and outside of the nitrogen deposition zone were analyzed for historical changes in diatom assemblages. Lake sediment cores were collected from a priori defined nitrogen (N - and phosphorus (P - limited lakes within and outside the N plume associated with the AOSR. Diatom assemblages were quantified at sub-decadal resolution since ca. 1890 to compare conditions prior to oil sands expansion and regional climate warming, to the more recent conditions in each group of lakes (Reference and Impacted, N- and P-limited lakes. Analyses of changes in assemblage similarity and species turnover indicates that changes in diatom assemblages were minimal both within and across all lake groups.  Small changes in percent composition of planktonic taxa, particularly small centric taxa (Discostella and Cyclotella species and pennate taxa, such as Asterionella formosa and Fragilaria crotonensis, occurred in some of the lakes. While these changes were consistent with potential climate effects on algal growth, water column stability and other factors; the timing and direction of biotic changes were variable among sites suggesting that any apparent response to climate was lake dependent. The absence of a consistent pattern of diatom changes associated with receipt of reactive nitrogen or intrinsic nutrient-limitation status of the lake

  4. Development of Petrov glacial-lake system (Tien Shan and outburst risk assessment

    Directory of Open Access Journals (Sweden)

    I. A. Torgoev


    Full Text Available Global climate warming causes an intensive melting and retreat of glaciers in the Tien Shan mountains. Melting water of glaciers causes overfilling of high mountain lakes. The increase of the surface and volume of the Petrov Lake accompanied with the decrease of stability of the dam represents an extremely dangerous situation that can produce a natural disaster. Failure can happen due to erosion, a buildup of water pressure, an earthquake or if a large enough portion of a glacier breaks off and massively displaces the waters in a glacial lake at its base. In case of the lake dam rupture, flooding of a disposal site of highly toxic tailing from the gold mine Kumtor is a threat. If this happens, the toxic waste containing cyanides would contaminate a large area in the Naryn (Syrdarya river basin. Even if the flooding of the disposal site does not occur, the damage after lake dam fracture will be immense due to the glacial lake outburst flood may be a devastating mudslide. In order to prevent or reduce the risk of this event we recommend performing engineering surveys for the development and implementation of the project for the controlled reduction of water level in the Blue Bay of the Petrov Lake to a safe volume.

  5. Water quality assessment of Kavvayi Lake of northern Kerala, India using CCME water quality index and biological water quality criteria. (United States)

    Shiji, M; Sabitha, A R; Prabhakar, Kavya; Harikumar, P S


    Assessment of water quality status of 7 sites of Kavvayi Wetland in northern Kerala (India) was carried out. The physico-chemical, bacteriological and biological parameters were monitored during pre-monsoon, monsoon and post-monsoon seasons. Canadian Council of Ministers of the Environment (CCME) water quality index of the Kavvayi Lake samples ranged from 43.99-44.77; indicating that water quality was threatened or impaired. The poor water quality status might be due to dumping of wastes from municipal and domestic sources and agricultural runoff. Biological water quality criteria (BWQC) determined for wetland revealed that stations such as mixing point of Kariangode River into Kavvayi Lake and Kottikkadavu was moderately polluted in pre-monsoon and post- monsoon seasons. Mixing point of Nileswar River into Kavvayi Lake was moderately polluted in pre-monsoon season. Both calculated indices suggest that quality of lake was found to be influenced by anthropogenic activities such as unscientific tourism and infrastructure development, land encroachment, sand mining, pollution etc. The study was carried out as part of a programme, which aimed to conserve Kavvayi wetland because of its unique ecological and environmental characteristics.

  6. Assessing water quality in a tropical lake using biomarkers in zebrafish embryos: developmental toxicity and stress protein responses. (United States)

    Hallare, A V; Pagulayan, R; Lacdan, N; Köhler, H R; Triebskorn, R


    In order to achieve a more substantial appraisal of lake water quality, the assessment must not be based only on chemical measurements and analyses of the water itself, but even more so on the impact of existing conditions on aquatic biota. This is possible with the use of biotests or biomarkers, e.g. investigations of the developmental parameters (96-h embryotoxicity evaluate) or of the induction of heat shock proteins (proteotoxicity evaluate). To evaluate the suitability of these tests for environmental screening, fertilized zebrafish eggs were exposed to water samples collected from five sites of varying levels of stress from Laguna Lake, Philippines. Reconstituted water was used as laboratory control while water samples from a highly polluted freshwater source was used as positive control. Developmental parameters were noted and described within 48 and 96 h of exposure. Dilution experiments of the positive control were also done to further assess and compare toxicity potentials of Laguna Lake waters with those originating from a polluted freshwater. After the 96-h exposure, the levels of stress proteins (hsp 70) were determined in embryos from all exposure groups. Results showed 100% mortality in embryos exposed to undiluted positive control (PC) within only 12 h. Increasing dilution levels, however, resulted in lower mortality and lower abnormality rates. No detectable developmental differences were noted among embryos exposed to either the laboratory control or Laguna Lake waters at the end of 96 h, regardless of the source. Very high survival rates and high hatching success rates were observed in embryos exposed to lake waters as well as laboratory control, and the data did not differ significantly among the groups. Likewise, no significant malformations were noted among all developing embryos throughout the exposure period. However, the levels of heat shock proteins in the two sites located closest to Manila, the Philippine capital (Northern West Bay and

  7. Eco-Hydrology From Space: How Satellites Can Be Harnessed To Assess Human Impacts On The Trophic Status Of Lakes In Forested Landscapes (United States)

    Sass, G. Z.; Creed, I. F.; Prairie, Y. T.


    The recent proliferation of spatially and temporally extensive geospatial datasets (e.g., Radarsat, Landsat) has created research opportunities into the characterization of eco-hydrological processes and patterns across Canada's vast forests. Herein, we demonstrate how these space based sensors can be used to establish the hydrologic controls on the range of natural variability (RNV) of lake trophic status and to assess thresholds in disturbance related to human activities that lead to the exceedance in RNV (i.e., lake trophic status that is outside the RNV). We focus on two lake districts in the boreal forest. One is on the western Boreal Plain, where average annual precipitation (P) is less than potential evapotranspiration (PET) (PPET and hydrology is characterized by simpler surface hydrologic dynamics. In each of these lake districts, we use Radarsat and Landsat imagery to map surface/near surface hydrologic flow paths (the conveyors of nutrients to and from lakes) and lake trophic status. We establish the RNV of trophic status in landscapes with minimal human presence and compare this to the trophic status of lakes where there is a significant human footprint caused by forest management activities. By building statistical models that account for differences in climate and hydrologic pathways within basins contributing to a lake, we are able to evaluate how much disturbance in forest hydrology is needed to result in a fundamental change in nutrient loading to the lakes and ultimately lake trophic status. We conclude that satellite sensors can assist in the establishment of realistic reference conditions against which effects of forest management activities on lake trophic status can be assessed and management targets can be established.

  8. Assessing Ecotourism from a Multi-stakeholder Perspective: Xingkai Lake National Nature Reserve, China (United States)

    Su, Ming Ming; Wall, Geoffrey; Ma, Zhong


    Ecotourism development is closely associated with the sustainability of protected natural areas. When facilitated by appropriate management, ecotourism can contribute to conservation and development, as well as the well-being of local communities. As such, ecotourism has been proposed and practiced in different forms in many places, including China. This study assesses ecotourism development at Xingkai Lake National Nature Reserve in Heilongjiang Province, China. Key informant interviews were conducted with representatives from the provincial Forestry Department, the Nature Reserve, and the local community. Observation was undertaken on three site visits and secondary data were collected. The potential for providing quality natural experiences is high and tourism development is occurring rapidly. However, current relationships between people, resources, and tourism have yet to provide mutual benefits necessary for successful ecotourism. The multi-stakeholder management style and the ambiguity of landownership within the nature reserve constitute structural difficulties for ecotourism management and operation. Although participation in ecotourism could provide a livelihood opportunity and interests in involvement in tourism have been identified among the local fishing community, current involvement is limited mainly due to the lack of mechanisms for participation. Therefore, it is recommended that management programs and government policies should be established to provide a platform for community participation in ecotourism. Then, a positive synergistic relationship between tourism, environment, and community could be developed. Planning and policy requirements are discussed for ecotourism development in protected areas in China.

  9. Assessing ecotourism from a multi-stakeholder perspective: Xingkai Lake National Nature Reserve, China. (United States)

    Su, Ming Ming; Wall, Geoffrey; Ma, Zhong


    Ecotourism development is closely associated with the sustainability of protected natural areas. When facilitated by appropriate management, ecotourism can contribute to conservation and development, as well as the well-being of local communities. As such, ecotourism has been proposed and practiced in different forms in many places, including China. This study assesses ecotourism development at Xingkai Lake National Nature Reserve in Heilongjiang Province, China. Key informant interviews were conducted with representatives from the provincial Forestry Department, the Nature Reserve, and the local community. Observation was undertaken on three site visits and secondary data were collected. The potential for providing quality natural experiences is high and tourism development is occurring rapidly. However, current relationships between people, resources, and tourism have yet to provide mutual benefits necessary for successful ecotourism. The multi-stakeholder management style and the ambiguity of landownership within the nature reserve constitute structural difficulties for ecotourism management and operation. Although participation in ecotourism could provide a livelihood opportunity and interests in involvement in tourism have been identified among the local fishing community, current involvement is limited mainly due to the lack of mechanisms for participation. Therefore, it is recommended that management programs and government policies should be established to provide a platform for community participation in ecotourism. Then, a positive synergistic relationship between tourism, environment, and community could be developed. Planning and policy requirements are discussed for ecotourism development in protected areas in China.

  10. Mapping landslide processes in the North Tanganyika - Lake Kivu rift zones: towards a regional hazard assessment (United States)

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


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

  11. Assessment of Available Phosphorus in the Lake Sediments Using an Innovative Composite Membrane (United States)

    Huang, Qinghui; Wang, Zijian; Wang, Donghong


    An innovative iron oxide embedded cellulose acetate membrane (FeO/CAM) was synthesized and used to study available phosphorus in Chinese lake sediments. The kinetics of available P release was investigated by FeO/CAM for different types of sediments ranging in Olsen-P from 19.1 to 170.6 mg/kg. The results showed that the average kd values (0.094 h-1) of the Taihu sediments were comparable to those of the soils with similar texture estimated by iron oxide impregnated filter paper (FeO paper) though they were generally lower than those of sandy soils. It is indicated that the FeO/CAM can be used as an infinite P sink to estimate available P (FeO-P). The concentrations of FeO-P were significantly correlated with those of extractable P forms, e.g. Olsen-P (R2 = 0.962, pCAM is useful to assess phosphorus bioavailability of the sediments.

  12. Assessing the legacy of red mud pollution in a shallow freshwater lake: arsenic accumulation and speciation in macrophytes


    Olszewska, Justyna P; Meharg, Andrew A.; Heal, Kate V.; Carey, Manus; Gunn, Iain D. M.; Searle, Kate R.; Winfield, Ian J.; Spears, Bryan M


    Little is known about long-term ecological responses in lakes following red mud pollution. Among red mud contaminants, arsenic (As) is of considerable concern. Determination of the species of As accumulated in aquatic organisms provides important information about the biogeochemical cycling of the element and transfer through the aquatic food-web to higher organisms. We used coupled ion chromatography and inductively coupled plasma mass spectrometry (ICP-MS) to assess As speciation in tissues...

  13. Assessment of the Response of Piscivorous Sportfishes to the Establishment of Gizzard Shad in Claytor Lake, Virginia


    Bonds, Charles Craig


    Gizzard shad were illegally introduced to Claytor Lake in the late 1980s and soon established a thriving population. This study assessed 1) the degree to which gizzard shad were utilized by piscivores (pelagic - striped bass Morone saxatilis, hybrid striped bass M. chrysops x M. saxatilis, and walleye Stizostedion vitreum, and three littoral black basses Micropterus spp.), 2) the availability of gizzard shad as potential prey as determined from age and growth analysis, and 3) the performance ...

  14. Spatially explicit exposure assessment for small streams in catchments of the orchard growing region `Lake Constance (United States)

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


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

  15. [Pollution Characteristics and Ecological Risk Assessment of PAHs in Water and Fishes from Daqing Lakes]. (United States)

    Wang, Xiao-di; Zang, Shu-ying; Zhang, Yu-hong; Wang, Fan; Yang, Xing; Zuo, Yi-long


    The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in 30 water samples and 5 tissues (gill, liver, brain, kidney and muscle) of 36 fishes which were collected from 18 typical lakes of the Daqing lakes group, China were measured between February and April 2012. The results of PAHs concentrations in the water showed that the range of total concentrations was 0.2-1.21 μg x L(-1) and the highest concentration was found in the Yueliangpao Lake. Clustering analysis of statistical method was used to classify the concentrations of PAHs in the water of 18 lakes, and PAHs source and evaluation of ecological risk in different lake groups were obtained respectively based on the analysis of PAHs ratio and the species sensitivity distributions method. The results of cluster analysis about PAHs concentrations in the water of 18 lakes showed that all the lakes were divided into 4 lake groups. Yueliangpao (YLP) and dongdahai (DDH) lakes were respectively divided into a separate group and the other 14 lakes were divided into two groups named XHH group and DQSK group. PAHs in the water of lakes were mainly from wood and coal burning except that the PAHs of the water in YLP group was caused by oil contamination. According to the surface water quality standard of the world and China, the concentrations of PAHs in the water of 4 lake groups all exceeded the standard variously. The PAHs concentrations of most water samples in YLP group and XHH group exceeded the 16 PAHs limit value of Environmental Protection Agency (US EPA) standard, especially, the concentration of Benz[a] pyrene with the strongest carcinogenicity of YLP group exceeded Chinese surface water quality standard. While in the DQSK lake group and the DDH lake group, several PAHs contaminations of water samples exceeded the standard. The tested and statistical results of 16 PAHs concentrations in 5 tissues of Cyprinus carpio and Hypophthalmichthys molitrix fish species in Daqing lakes showed the concentrations

  16. Playa Lakes of the Texas High Plains: A contaminants survey & assessment of biological integrity (United States)

    US Fish and Wildlife Service, Department of the Interior — In response to increased interest in the quality of playa lakes and their recognition as valuable wildlife habitat, the Arlington Field Office of the U.S. Fish and...

  17. Pesticide Impact Assessment in Tule Lake and Lower Klamath National Wildlife Refuges, 1998 - 2000 Growing Season (United States)

    US Fish and Wildlife Service, Department of the Interior — Tule Lake and the adjacent Lower Klamath National Wildlife Refuges (TLNWR and LKNWR) serve as key spring/fall staging and overwintering areas for Pacific Flyway...

  18. Phase 1 Watershed Assessment Final Report: Lake Andes Watershed, Charles Mix County, South Dakota. (United States)

    US Fish and Wildlife Service, Department of the Interior — Lake Andes was included in the 1998 South Dakota 303(d) list as an impairment-related Total Maximum Daily Load waterbody. In 1922 Congress passed a bill that...

  19. Detroit Lakes Wetlands Management District: Comprehensive Conservation Plan and Environmental Assessment (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Detroit Lakes Wetlands Management District for the next 15 years. This plan outlines...

  20. Glacial Lake Outburst Floods in the Sagarmatha Region: Hazard Assessment Using GIS and Hydrodynamic Modeling

    National Research Council Canada - National Science Library

    Birendra Bajracharya; Arun Bhakta Shrestha; Lokap Rajbhandari


    Glacial lake outburst floods (GLOFs) are common natural hazards in the Himalaya. These floods, usually of large magnitude, can severely affect fragile mountain ecosystems and their limited economic activities...

  1. Final Environmental Assessment for transfer of Indian Lakes area to Churchill County, Nevada (United States)

    US Fish and Wildlife Service, Department of the Interior — The USFWS proposes to transfer the Indian Lakes portion of the Stillwater Wildlife Management Area to Churchill County, Nevada for the purposes of fish, wildlife,...

  2. Environmental Assessment Proposal to Protect Wildlife Habitat at Lake Umbagog 1991 (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this United States Fish & Wildlife Service proposal is to ensure the long-term protection of unique wetland habitats adjacent to Lake Umbagog, on...

  3. Environmental assessment of drainage water impacts on water quality and eutrophication level of Lake Idku, Egypt. (United States)

    Ali, Elham M; Khairy, Hanan M


    Lake Idku, northern Egypt, receives large quantities of drainage water from four main discharging drains. Ecological and biological status of Lake Idku has been monitored during (autumn 2012 to summer 2013) to examine the lake water quality and eutrophication level in response to the quality as well as the source of the discharging water. Discrete water samples were collected from the lake body and the drains. Chemical analyses revealed an excessive nutrient load goes into the lake. A range of 1.4-10.6 mg nitrites/L was determined for drain waters, however a sudden increase was observed in lake and drain water samples of up to 84 and 74.5 mg/L, respectively. Reactive silicate ranged between 2.9 and 4.8 mg/L; while inorganic phosphate fluctuated between 0.2 and 0.43 mg/L. Transparency varied from 45 cm to 134 cm with better light conditions at drain sites. Biological results indicated a hyper-eutrophic status for the lake with a range of chlorophyll-a varied from a minimum of 39.9 μg/L (at Idku Drains) and a maximum of 104.2 μg/L (at El-Khairy drain). Phytoplankton community structure revealed higher abundance at lake sites compared with the drains. Maximum phytoplankton density was detected during summer with the dominance of Bacilariophyceae (e.g. Cyclotella meneghiniana, Cyclotella comate, Melosira varians) followed by Chlorophycean taxon (e.g. Scenedesmus dimorphus, S. bijuga and Crucigenia tetrapedia). Five indices were applied to evaluate the water quality of the lake. Diversity Index (DI) indicated slight to light pollution along all sites; while Sapropic Index (SI) indicated slight pollution with acceptable oxygen conditions and an availability of sensitive species. Palmer Index (PI) gave a strong evidence of high organic pollution at some sites in the lake, while Generic Diatom Index (GDI) revealed that levels of pollution varied from average to strong. Trophic Index (TI), suggest that there are an obvious signs of eutrophication in the lake

  4. Use of Geoenvironmental Impact of Climate Change in Management and Assessment Lake Nasser, Egypt (United States)

    Sayed El Gammal, El


    This study monitor how to management the water stored after High Dam in the biggest artificial global lake (Lake Nasser), Integration of physical features and water level changes within the lake curse and margins. Statistical data presented, interpreted and correlated with using remote sensing technique in change detection. Different Landsat images acquired at different times (1970, 1982, 1987, 2000, 2003 and 2008) have been used by the ERDAS and ARC-GIS techniques to estimate the movements of lake borders and water fluctuation proportional to water sizes in place. Regards to water fluctuation degree, the lake can be divide into 4 classes in lake's sectors: 1, show maximum change degree, 2 show medium change degree, 3 slight to neglected change degree, and 4, no change. Functions control the water fluctuation in Lake Nasser are; (i) the granite and Nubia sandstone outcrops, (ii) NW, E-W and NE structure in order, (iii) low topography. Water level change detection on Landsat images in different dates elucidates big variation between different lake sectors, there are strangle points and other useful localities that yields environmental implication. The strangle points detected in the curse of River Nile and after 40 years since lake initiation, the water are more strangled in this curse because of the water velocity before the High Dam was high speed can pass toward the north in Nile annual flood but after the dam, the water velocity decreased. Due to decrease of velocity, the water go to narrow incised wadis (Khors) in the Nile high flood plus the sands drift, these khors are bounded by hard Nubia sandstone already saturated by water and it consider the main underground water reservoir in Egypt. In addition, the entrance of the lake in Halfa inside Sudan is subjected to suspended sediments (mud) forming new delta plus the sands drift that impair the reservoir in Egypt. Wadi Allaqui have 250 km length and 2 km average width, it's is the 5th order channel inside a

  5. Satellite-Based Assessment of the spatial extent of Aquatic Vegetation in Lake Victoria (United States)

    Clark, W.; Aligeti, N.; Jeyaprakash, T.; Martins, M.; Stodghill, J.; Winstanley, H.


    Lake Victoria in Africa is the second largest freshwater lake in the world and is known for its abundance of aquatic wildlife. In particular over 200 different fish species are caught and sold by local fisherman. The lake is a major contributor to the local economy as a corridor of transportation, source of drinking water, and source of hydropower. However, the invasion of aquatic vegetation such as water hyacinth in the lake has disrupted each of these markets. Aquatic vegetation now covers a substantial area of the coastline blocking waterways, disrupting hydropower, hindering the collection of drinking water and decreasing the profitability of fishing. The vegetation serves as a habitat for disease carrying mosquitoes as well as snakes and snails that spread the parasitic disease bilharzia. The current control measures of invasive aquatic vegetation rely on biological, chemical and mechanical control. The objective of this study was to utilize remote sensing to map aquatic vegetation within Lake Victoria from 2000 to 2011. MODIS, Landsat 4-5TM, and Landsat 7-ETM imagery was employed to perform change detections in vegetation and identify the extent of aquatic vegetation throughout the years. The efficiency of containment efforts were evaluated and ideal time for application of such efforts were suggested. A methodology for aquatic vegetation surveillance was created. The results of this project were presented as a workshop to the Lake Victoria Fisheries Organization, SERVIR, and other partner organizations. The workshop provided instruction into the use of NASA and other satellite derived products. Time series animations of the spatial extent of aquatic vegetation within the lake were created. By identifying seasons of decreased aquatic vegetation, ideal times to employ control efforts were identified. SERVIR will subsequently utilize the methodologies and mapping results of this study to develop operational aquatic vegetation surveillance for Lake Victoria.

  6. An integrated assessment for wind energy in Lake Michigan coastal counties. (United States)

    Nordman, Erik; VanderMolen, Jon; Gajewski, Betty; Isely, Paul; Fan, Yue; Koches, John; Damm, Sara; Ferguson, Aaron; Schoolmaster, Claire


    The benefits and challenges of onshore and offshore wind energy development were assessed for a 4-county area of coastal Michigan. Economic, social, environmental, and spatial dimensions were considered. The coastal counties have suitable wind resources for energy development, which could contribute toward Michigan's 10% renewable energy standard. Wind energy is cost-effective with contract prices less than the benchmark energy price of a new coal-fired power plant. Constructing a 100 MW wind farm could have a $54.7 million economic impact. A patchwork of township-level zoning ordinances regulates wind energy siting. Voluntary collaborations among adjacent townships standardizing the ordinances could reduce regulatory complexity. A Delphi Inquiry on offshore wind energy in Lake Michigan elicited considerable agreement on its challenges, but little agreement on the benefits to coastal communities. Offshore turbines could be acceptable to the participants if they reduced pollution, benefited coastal communities, involved substantial public participation, and had minimal impact on property values and tourism. The US Coast Guard will take a risk-based approach to evaluating individual offshore developments and has no plans to issue blanket restrictions around the wind farms. Models showed that using wind energy to reach the remainder of the 10% renewable energy standard could reduce SO2 , NOx , and CO2 pollution by 4% to 7%. Turbines are highly likely to impact the area's navigational and defense radar systems but planning and technological upgrades can reduce the impact. The integrated assessment shows that responsible wind energy development can enhance the quality of life by reducing air pollution and associated health problems and enhancing economic development. Policies could reduce the negative impacts to local communities while preserving the benefits to the broader region. © 2015 SETAC.

  7. Comprehensive risk assessment of heavy metals in lake sediment from public parks in Shanghai. (United States)

    Yang, Jing; Chen, Ling; Liu, Li-Zao; Shi, Wei-Ling; Meng, Xiang-Zhou


    Rapid urbanization has caused potential pollution of heavy metal in Shanghai. A comprehensive pollution study of heavy metals (Cd, Cu, Pb, and Zn) in 35 lake surface sediments from city parks in the four different urbanized areas of Shanghai was conducted. Intensive human activities caused moderate enrichment of the four metals in highly urbanized areas, especially Cd with the significant enrichment in the central urban core area. However, the levels of the four metals in all the sediments were lower than the corresponding consensus-based Probable Effect Concentration, indicating adverse effects not to occur frequently. The integrated pollution assessments of multiple heavy metals also suggested low ecological risk and 15-29 percent probability of toxicity in most of sediments. The metal speciation analysis showed that Cd, Cu, Pb, and Zn were dominated by the non-residual fractions and thus they have high mobility and bioavailability, indicating significant anthropogenic sources. According to the Risk Assessment Code, Cd had the highest bioavailable fraction and represented high or very high risk, followed by Zn with medium or high risks in most of samples, while no or low risk was found for Cu and Pb at most sites because they were dominated by reducible and residual fractions. Correlation analysis showed that chemical fractions of heavy metals were prone to transform among each other if environmental conditions changed. Therefore, in view of anthropogenic inputs and speciation distribution, heavy metals with very high bioavailability at very low total levels and those with low bioavailability at very high total levels should not be ignored. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Ecotoxicological assessment of flocculant modified soil for lake restoration using an integrated biotic toxicity index. (United States)

    Wang, Zhibin; Zhang, Honggang; Pan, Gang


    Flocculant modified soils/clays are being increasingly studied as geo-engineering materials for lake restoration and harmful algal bloom control. However, the potential impacts of adding these materials in aquatic ecological systems remain unclear. This study investigated the potential effects of chitosan, cationic starch, chitosan modified soils (MS-C) and cationic starch modified soils (MS-S) on the aquatic organisms by using a bioassay battery. The toxicity potential of these four flocculants was quantitatively assessed using an integrated biotic toxicity index (BTI). The test system includes four aquatic species, namely Chlorella vulgaris, Daphnia magna, Cyprinus carpio and Limnodrilus hoffmeisteri, which represent four trophic levels in the freshwater ecosystem. Results showed that median effect concentrations (EC50) of the MS-C and MS-S were 31-124 times higher than chitosan and cationic starch, respectively. D. magna was the most sensitive species to the four flocculants. Histological examination of C. carpio showed that significant pathological changes were found in gills. Different from chitosan and cationic starch, MS-C and MS-S significantly alleviated the acute toxicities of chitosan and cationic starch. The toxicity order of the four flocculants based on BTI were cationic starch > chitosan > MS-S > MS-C. The results suggested that BTI can be used as a quantitative and comparable indicator to assess biotic toxicity for aquatic geo-engineering materials. Chitosan or cationic starch modified soil/clay materials can be used at their optimal dosage without causing substantial adverse effects to the bioassay battery in aquatic ecosystem. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Assessing feeding competition between lake whitefish Core-gonus clupeaformis and round whitefish Prosopium cyl-indraceum


    Andrew MACPHERSON, John A. HOLMES, Andrew M. MUIR,David L. G. NOAKES


    We collected lake whitefish Coregonus clupeaformis and round whitefish Prosopium cylindraceum from the main basin of Lake Huron and Georgian Bay in the Laurentian Great Lakes of North America to investigate details of diet and feeding tactics of these species in different seasons. Lake whitefish supports important commercial fisheries in Lake Huron and both species make use of habitats near the Bruce Nuclear Power Development, on the eastern shore of Lake Huron. Most fish of both species sho...

  10. Water-quality models to assess algal community dynamics, water quality, and fish habitat suitability for two agricultural land-use dominated lakes in Minnesota, 2014 (United States)

    Smith, Erik A.; Kiesling, Richard L.; Ziegeweid, Jeffrey R.


    Fish habitat can degrade in many lakes due to summer blue-green algal blooms. Predictive models are needed to better manage and mitigate loss of fish habitat due to these changes. The U.S. Geological Survey (USGS), in cooperation with the Minnesota Department of Natural Resources, developed predictive water-quality models for two agricultural land-use dominated lakes in Minnesota—Madison Lake and Pearl Lake, which are part of Minnesota’s sentinel lakes monitoring program—to assess algal community dynamics, water quality, and fish habitat suitability of these two lakes under recent (2014) meteorological conditions. The interaction of basin processes to these two lakes, through the delivery of nutrient loads, were simulated using CE-QUAL-W2, a carbon-based, laterally averaged, two-dimensional water-quality model that predicts distribution of temperature and oxygen from interactions between nutrient cycling, primary production, and trophic dynamics.The CE-QUAL-W2 models successfully predicted water temperature and dissolved oxygen on the basis of the two metrics of mean absolute error and root mean square error. For Madison Lake, the mean absolute error and root mean square error were 0.53 and 0.68 degree Celsius, respectively, for the vertical temperature profile comparisons; for Pearl Lake, the mean absolute error and root mean square error were 0.71 and 0.95 degree Celsius, respectively, for the vertical temperature profile comparisons. Temperature and dissolved oxygen were key metrics for calibration targets. These calibrated lake models also simulated algal community dynamics and water quality. The model simulations presented potential explanations for persistently large total phosphorus concentrations in Madison Lake, key differences in nutrient concentrations between these lakes, and summer blue-green algal bloom persistence.Fish habitat suitability simulations for cool-water and warm-water fish indicated that, in general, both lakes contained a large

  11. Total cylindrospermopsins, microcystins/nodularins, and saxitoxins data for the 2007 United States Environmental Protection Agency National Lake Assessment (United States)

    Loftin, Keith A.; Dietze, Julie E.; Meyer, Michael T.; Graham, Jennifer L.; Maksimowicz, Megan M.; Toyne, Kathryn D.


    Phytoplankton communities in freshwater lakes, ponds, and reservoirs may be dominated by cyanobacteria (also called blue-green algae) under certain environmental conditions. Cyanobacteria may cause a range of water-quality impairments, including the potential for toxin production. Cyanobacteria toxins (cyanotoxins) may adversely impact human and ecological health. Microcystins are considered to be one of the most commonly found classes of cyanotoxins in freshwater ecosystems, and as such were selected as a recreational indicator of water quality for the 2007 United States Environmental Protection Agency (EPA) National Lakes Assessment. However, much less is known about the occurrence of other classes of cyanotoxins in fresh surface water such as anatoxins, cylindrospermopsins, nodularins, and saxitoxins.

  12. Psychometric analysis of measuring functional outcomes in tibial plateau fractures using the Short Form 36 (SF-36), Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires. (United States)

    Dattani, R; Slobogean, G P; O'Brien, P J; Broekhuyse, H M; Blachut, P A; Guy, P; Lefaivre, K A


    Patients participating in a modern prospective orthopaedic trauma database may be asked to complete many functional outcome measures, adding to the burden of study participation. This prospective study assessed the utility and responsiveness of the generic Short Form 36 (SF-36) and the disease specific Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires in 55 patients treated operatively for tibial plateau fractures with the goal of determining if there was clear benefit of using multiple measures in a lower extremity peri-articular fracture population. There was very good correlation between all three scores at 6 and 12 months, indicating they are measuring similar factors. Responsiveness was assessed using the standard response mean (SRM), proportion of patients attaining the minimal clinically important difference (MCID) between 6 and 12 months, and floor and ceiling effects. The SRM for the SF-36 was statistically higher than the SRM for the SMFA or the WOMAC. Significantly more patients were found to have a MCID between 6 and 12 months post-surgery based on the SF-36 than the other two functional scores. There was no floor effect found on any of the 3 functional scores evaluated; however, a significant ceiling effect was noted with the WOMAC but not with the SF-36 or the SMFA. These results, along with the usefulness of the SF-36 for comparing disease burden across populations, favour the SF-36 as the instrument of choice in assessing functional outcome in patients with tibial plateau fractures. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. The Argentinean network for the assessment and monitoring of Pampean shallow-lakes (PAMPA2) (United States)

    Zagarese, H. E.


    The Pampa region of Argentina is an extensive wetland containing nearly 200,000 shallow-lakes. The region is under increasing agricultural pressure resulting from climate change (increased temperature and precipitation) and the substitution of cattle breeding and traditional cultures by transgenic soy. Among the many services that they provide, shallow-lakes are highly responsive to changes in climate and land use. Therefore, long-term studies of shallow-lakes provide useful clues to understand and track changes occurring in their complex watersheds. PAMPA2 is a recently funded, long-term network project, with wide geographic coverage, aimed at studying Pampean shallow-lakes. Thirteen network sites (i.e., shallow lakes) occurring along the precipitation gradient (from 1000 mm y-1) form the core of the project. The network integrates various research teams from eight universities and research centers, with a strong multidisciplinary component. The approaches combine traditional sampling; high-rate monitoring using automated sensors; and remote sensing. The network develops and manufactures most the instruments, including automated buoys and unmanned aircrafts. In this presentation, we will provide details on the structure and state of development of the PAMPA2 network, and present a long-term case study of a large Pampean shallow-lake, exemplifying the strong dependence of lake processes on weather variables. Laguna Chascomús is a large, hypertrophic shallow-lake. Chascomús is one of the PAMPA2 study sites that have been more extensively studied. In this shallow-lake, high nutrient availability permits the development of a dense microbial plankton community, which in turn translates into exceptionally high water turbidity. Phytoplankton primary production is strongly limited by light availability. As a consequence, turbidity is strongly and positively correlated to the incoming solar radiation, resulting in a remarkable seasonal pattern of water transparency

  14. Emergency satellite observation and assessment of a glacier lake outburst flood in Bhutan (United States)

    Nagai, Hiroto; Tadono, Takeo; Suzuki, Shinichi


    Following a glacial lake outburst flood (GLOF) on Jun. 28, 2015, in western Bhutan, the Japan Aerospace Exploration Agency performed an emergency observation on Jul. 2, 2015 using the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) onboard the Advanced Land Observing Satellite-2 (ALOS-2, "DAICHI-2"). Based on a dataset generated from the Advanced Land Observing Satellite (ALOS) imagery, "The Glacial Lake Inventory of Bhutan using ALOS Data", the glacier lake that potentially contributed to this GLOF were identified at 28°4'7.7"N, 89°34'50.0"E, in a headwater of the Mo Chu river basin, western Bhutan. A post-event lake outline was delineated manually using the acquired PALSAR-2 image. Pre-event outlines were delineated from previously acquired PALSAR-2 images (Apr. 23, 2015), Landsat 8 (Mar. 8, 2015), and ALOS (Dec. 22, 2010). The differences between these outlines reveal a remarkable expansion (+48.0%) from Mar. 8 to Apr. 23, 2015, followed by a remarkable shrinkage (-52.9%) from Apr. 23 to Jul. 2, 2015. This result indicates the lake to be a highly likely source of the flood. Topographically, it is located at a glacier terminus, surrounded by a moraine. Differing backscatter patterns between successive PALSAR-2 images in a certain part of the moraine suggest that it underwent some collapse, possibly as a result of the GLOF. More detailed investigations, including field surveys, are necessary to fully reveal and understand this event.

  15. Application of MODIS Imagery for Intra-Annual Water Clarity Assessment of Minnesota Lakes

    Directory of Open Access Journals (Sweden)

    Margaret L. Voth


    Full Text Available Monitoring of water clarity trends is necessary for water resource managers. Remote sensing based methods are well suited for monitoring clarity in water bodies such as the inland lakes in Minnesota, United States. This study evaluated the potential of using imagery from NASA’s MODIS sensor to study intra-annual variations in lake clarity. MODIS reflectance images from six dates throughout the 2006 growing season were used with field collected Secchi disk transparency data to estimate water clarity in large lakes throughout Minnesota. The results of this research indicate the following: water clarity estimates derived from MODIS imagery are largely similar to those derived from lower temporal resolution sensors such as Landsat, robust water clarity estimates can be derived using MODIS for many dates throughout a growing season (R2 values between 0.32 and 0.71, and the relatively low spatial resolution of MODIS restricts its applicability to a subset of the largest inland lakes (>160 ha, or 400 acres. This study suggests that water clarity maps developed with MODIS imagery and bathymetry data may be useful tools for resource managers concerned with intra- and inter-annual variations in large inland lakes.


    Directory of Open Access Journals (Sweden)

    Ryszard Konieczny


    Full Text Available In the summer of 2008–2009 species composition and quantity of macrozoobenthos in deposits samples collected with Ekman gripping device at 4 points of Starzyc Lake was studied. Lake Starzyc also called Chociwel is located in West Pomeranian Voivodeship and is adjacent to the town of Chociwel from South and South East of the city. In the collected material of the analysed lake macrozoobenthos organisms from the following classes were found: Oligochaeta, Hirudinea, Crustacea, Insecta and Bivalvia. The Insecta class was the most numerous one in respect of species found, including larvae of the following orders: Ephemeroptera (Leptophlebia sp., Ephemera sp., Caenis macrura (Stephens, Trichoptera (Limnephilidae, Leptoceridae, Cyrnus sp. Diptera and Megaloptera (Sialis lutaria L.. The density and biomass distribution in the analysed Starzyc Lake demonstrates the occurrence of unfavourable changes which may lead to eutrophication in the shallowest layers of the body reservoir and in the zone at the depth of 4.9 m. The littoral zone of the studied lake features high density and significant benthic fauna biomass with low values of PIE biodiversity index.

  17. Attitudes of Ontario psychiatrists towards health insurance.


    Lippman, D. H.; Lowy, F H; Rickhi, B


    In 1979 the opinions of Ontario psychiatrists were sought regarding the influence of the Ontario Health Insurance Plan (OHIP) on the practice of their specialty. Full replies to a 44-item questionnaire were received from more than half the certified psychiatrists in Ontario, half of whom had been in practice before the introduction of OHIP. Both satisfaction and uneasiness were expressed about most aspects of health insurance. Many of the 416 psychiatrists stated that OHIP had improved acces...

  18. Assessment of the mutagenic potential of Skadar Lake sediments using the salmonella microsomal assay

    Directory of Open Access Journals (Sweden)

    Perović Svetlana


    Full Text Available Organic extracts of sediments from Skadar Lake (National park and protected RAMSAR site were investigated for their mutagenic potential using Salmonella typhimurium TA98 and TA100 strains in the presence and absence of metabolic activation. Five different concentrations of sediment extracts from five different sampling sites were assayed, and mutagenic results were obtained for both strains. These studies present a part of the EULIMNOS project and included a battery of bioassay testing and in situ investigations of microbial community structures of Skadar Lake sediments. The obtained results show mutagenic risk potential in five collected samples in the absence and presence of metabolic activation. Additional studies are required in order to identify and quantify the chemical compounds responsible for the mutagenic activity present in Skadar Lake sediments.

  19. Charophytes of the lake Garda (Northern Italy: a preliminary assessment of diversity and distribution

    Directory of Open Access Journals (Sweden)

    Rossano Bolpagni


    Full Text Available Charophytes (stoneworts and bassweeds are a typical macrophytic component of inland water ecosystems. Well-developed submerged meadows of charophytes are expression of clear water and rather low phytoplankton concentrations. Consequently, among aquatic macroscopic primary producers, charophytes are one of the most threatened groups being very sensitive to phosphorous availability, turbidity and water level perturbations. Accordingly, charophytes have been suffering a massive diversity loss worldwide over the last century, mainly because of human-induced pressures. During summer 2011, detailed field surveys were carried out with the main purpose of filling knowledge gaps concerning aquatic flora and vegetation of the lake Garda – the largest lake in Italy and one of the deepest in Europe. Along randomly selected transects, floristic data were collected following standard procedures, as imposed by the Water Framework Directive. Overall, 12 different species of charophytes were recorded, which accounts for 36% of total Italian charophytes and 19% of European species. The most diffuse species were Chara globularis and C. intermedia; whereas, the most interesting taxa were Chara polyacantha and Nitella hyalina, two species with narrow distribution in Italy. Overall in the lake Garda, dense stands of charophytes covered almost homogeneously the littoral sectors at a water depth between 3 and 12 m. The deepest species was C. globularis, which reached a maximum depth of colonisation of about 17.5 m. Charophytes represent a major element among the primary producers in the lake Garda. The high local charophyte diversity and the rather wide most colonised areas (~1000-1200 ha confirm that the lake Garda is an important reserve for many rare and threatened charophytes. For the first time, these results highlight the key role of the lake Garda for charophyte diversity at a national and European level.

  20. Isolation prevalence of pulmonary nontuberculous mycobacteria in Ontario in 2007. (United States)

    Al Houqani, Mohammed; Jamieson, Frances; Chedore, Pamela; Mehta, Mauli; May, Kevin; Marras, Theodore K


    The reported prevalence of pulmonary nontuberculous mycobacteria (NTM) infections is increasing. To determine the 'isolation prevalence' of NTM in 2007 and compare it with previously published research that examined the increasing rates of isolation of NTM from clinical pulmonary specimens between 1997 and 2003. Isolation prevalence was investigated retrospectively by reviewing a cohort of all positive pulmonary NTM culture results from the Tuberculosis and Mycobacteriology Laboratory, Public Health Laboratory (Toronto, Ontario) in 2007, which identifies at least 95% of NTM isolates in Ontario. Isolation prevalence was calculated as the number of persons with a pulmonary isolate in a calendar year divided by the contemporary population and expressed per 100,000 population. Changes in isolation prevalence from previous years were assessed for statistical significance using generalized linear models with a negative binomial distribution. In 2007, 4160 pulmonary isolates of NTM were collected from 2463 patients. The isolation prevalence of all species (excluding Mycobacterium gordonae) was 19 per 100,000 population in 2007 - an increase from previous observations reported for Ontario - corresponding to an average annual increase of 8.5% from 1997 to 2007 (Pisolation prevalence of Mycobacterium avium complex (8.8%, Pmycobacteria remained relatively stable. The isolation prevalence of pulmonary NTM continues to increase significantly in Ontario, supporting the belief that pulmonary NTM disease is increasingly common.

  1. The New Articulation of Equity Education in Neoliberal Times: The Changing Conception of Social Justice in Ontario (United States)

    Rezai-Rashti, G.; Segeren, A.; Martino, W.


    In this paper, we draw attention to the impact of neoliberal globalisation in rearticulating conceptions of equity within the Ontario context. The Ontario education system has been hailed for its top performance on Programme for International Student Assessment (PISA) as a high-equity/high-quality education system and created "PISA envy"…

  2. Reservoir sedimentation and environmental degradation: assessing trends in sediment-associated trace elements in Grenada Lake, Mississippi. (United States)

    Bennett, Sean J; Rhoton, Fred E


    Sediments impounded within flood control reservoirs are potentially important archives of environmental and geomorphic processes occurring within drainage basins. The concentrations of select sediment-associated trace elements were assessed within the impoundment of Grenada Lake, a relatively large flood control reservoir in Mississippi with a history of contaminant bioaccumulation in fish. The post-construction sediments (after 1954) are discriminated from the pre-construction sediments (before 1954) based on depth variations in sediment texture and 137Cs emissions. The concentrations of select trace elements of the post-1954 sediments all are statistically greater than the pre-1954 sediments, and these same sediments also are enriched in clay. Once these concentrations are normalized by clay content, all trace elements in the post-1954 sediments are lower in concentration than the pre-1954 normalized sediments. Moreover, the trace elements when normalized by clay or Al content show virtually no change vertically (over time) within the reservoir impoundment. This suggests that the sources of these sediment-associated trace elements within Grenada Lake, whether natural or anthropogenic, have not changed appreciably over the lifespan of the reservoir and that the degradation of sedimentologic and ecologic indices within the lake are due to the sequestration of clay or clay-sized materials.

  3. Oil heritage district : Lambton County Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Shearer, W. [Wendy Shearer Landscape Architect, Kitchener, ON (Canada)


    This paper discussed a project conducted to assess the cultural heritage values of oil field equipment in Lambton County, Ontario. Oil was discovered in the region in 1858, after which a boom and bust cycle of exploration created a large rural-industrial landscape. The region now contains a unique collection of historic oil equipment. The region's industrial footprint is interwoven with village settlements, agricultural settlements, and a railway and road network linking the region to remote refineries. Oil wells in the region still operate using a jerker line system developed in the early twentieth century. The operational oil wells are subject to fluctuating oil prices and environmental protection requirements. The project presents a rare opportunity to place industrial heritage conservation directly in the hands of business operators and regulators, while also functioning as part of a living community. 2 figs.

  4. Harnessing the potential of the multi-indicator palaeoecological approach: an assessment of the nature and causes of ecological change in a eutrophic shallow lake


    Bennion, H.; Davidson, T. A.; Sayer, C. D.; Simpson, G. L.; Rose, N. L.; Sadler, J. P.


    SUMMARY 1. Multi-indicator palaeoecological studies have become increasingly popular over the last decade as the need for a more complete understanding of lake ecological histories has increased. However, the true potential of the full biological record for assessing the potential drivers of observed ecological shifts in lake sediment records has rarely been demonstrated. 2. Here, we examine the remains of a range of food-web components including algae (diatoms), macrophytes (plant macrofossi...

  5. Pharmaceuticals, hormones and bisphenol A in untreated source and finished drinking water in Ontario, Canada - Occurrence and treatment efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Kleywegt, Sonya; Pileggi, Vince [Standards Development Branch, Ontario Ministry of the Environment, 40 St. Clair Avenue West, Toronto, Ontario, M4V 1M2 (Canada); Yang, Paul, E-mail: [Laboratory Services Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario, M9P 3V6 (Canada); Hao Chunyan; Zhao Xiaoming [Laboratory Services Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario, M9P 3V6 (Canada); Rocks, Carline [Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario, M9P 3V6 (Canada); Thach, Serei [Laboratory Services Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario, M9P 3V6 (Canada); Cheung, Patrick; Whitehead, Brian [Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario, M9P 3V6 (Canada)


    The Ontario Ministry of the Environment (MOE) conducted a survey in 2006 on emerging organic contaminants (EOCs) which included pharmaceuticals, hormones and bisphenol A (BPA). The survey collected 258 samples over a 16 month period from selected source waters and 17 drinking water systems (DWSs), and analyzed them for 48 EOCs using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and isotope dilution mass spectrometry (IDMS) for the highest precision and accuracy of analytical data possible. 27 of the 48 target EOCs were detected in source water, finished drinking water, or both. DWSs using river and lake source water accounted for > 90% detections. Of the 27 EOCs found, we also reported the first detection of two antibiotics roxithromycin and enrofloxacin in environmental samples. The most frequently detected compounds ({>=} 10%) in finished drinking water were carbamazepine (CBZ), gemfibrozil (GFB), ibuprofen (IBU), and BPA; with their concentrations accurately determined by using IDMS and calculated to be 4 to 10 times lower than those measured in the source water. Comparison of plant specific data allowed us to determine removal efficiency (RE) of these four most frequently detected compounds in Ontario DWSs. The RE of CBZ was determined to be from 71 to 93% for DWSs using granulated activated carbon (GAC); and was 75% for DWSs using GAC followed by ultraviolet irradiation (UV). The observed RE of GFB was between 44 and 55% in DWSs using GAC and increased to 82% when GAC was followed by UV. The use of GAC or GAC followed by UV provided an RE improvement of BPA from 80 to 99%. These detected concentration levels are well below the predicted no effect concentration or total allowable concentration reported in the literature. Additional targeted, site specific comparative research is required to fully assess the effectiveness of Ontario DWSs to remove particular compounds of concern. - Research Highlights: {yields} Occurrence and typical range of 45

  6. A simple DEM assessment procedure for gully system analysis in the Lake Manyara area, northern Tanzania

    NARCIS (Netherlands)

    Maerker, Michael; Quénéhervé, Geraldine; Bachofer, Felix; Mori, Simone


    Gully erosion is a major threat concerning landscape degradation in large areas along the northern Tanzanian Rift valley. It is the dominant erosion process producing large parts of the sediments that are effectively conducted into the river network. The study area is located in the Lake

  7. National Water-Quality Assessment Program: Great Salt Lake basins study unit (United States)

    Waddell, Kidd M.


    The Great Salt Lake Basins NAWQA study will increase the scientific understanding of the factors that influence surface- and ground-water quality. This information will benefit water-resources managers that need, but often lack, the data required to implement effective water-quality management actions and evaluate long-term changes in water quality.

  8. Assessment of DDT, HCH and PCB pollution of lake sediments in Poland

    Directory of Open Access Journals (Sweden)

    Bojakowska Izabela


    Full Text Available In the years 2010-2013, 528 samples of surface sediments were collected from lake depths in the area of Poland. The content of 7 PCB congeners, HCH isomers and p,p’-DDT, p,p’-DDE and p,p’-DDD was determined using the GC-ECD method. The studies showed the common occurrence of organochlorine compounds in lake sediments in Poland. The presence of HCHs, at a concentration above the determination limit, was detected in 83.71% of samples, that of DDTs in 98.86% of samples, and of PCBs in 98.86% of samples. The maximum HCH concentration was 60.7 ng g-1, that of DDTs 602.9 ng g-1, and of PCBs 50.7 ng g-1, while the averages were 6.3 ng g-1, 19.2 ng g-1 and 2.8 ng g-1, respectively. High levels of DDTs are found in sediments of those lakes upon which major towns are located, whereas the highest HCH concentrations are observed in sediments of the lakes upon which holiday centres and agrotourism facilities have developed. The ratio of concentrations of total DDT metabolites to p,p’-DDT was above 2 in almost all samples, and the value was most frequently from several to tens (average 28.3. Sediments of some lakes contain higher concentrations of γ-HCH and DDT metabolites than their PEC values, the content of γ-HCH was higher in 1.89% of the analysed samples, the content of p,p’-DDE in 3.78% of the samples, and the content of p,p’-DDD in 7.38% of the samples. Concentrations of p,p’-DDT and PCB in excess of the PEC value were not found in any of the samples tested.

  9. Assessing the Impacts of Climate Change on Tourism-Dependent Communities in the Great Lakes (United States)

    Chin, N.; Day, J.; Sydnor, S.; Cherkauer, K. A.


    Tourism is an essential element of the Laurentian Great Lakes economy as well as one of the sectors expected to be affected most by climate change, particularly through extreme weather events. While studies looking at climate change impacts on the Great Lakes tourism, specifically, are limited, the results of other studies suggest that both summer tourism activities, such as beach-going, and winter tourism activities, such as skiing and snowboarding, could feel the effects of a changing climate. The purpose of this study was to determine how existing data and models might be used to predict the potential impacts of climate change on tourism-dependent communities at the local scale. Future climate projections and variable infiltration capacity (VIC) model simulations based on historical climate data were used to quantify trends in environmental metrics with a potential influence on tourism for several tourism-dependent Great Lakes communities. The results of this research show that the potential impacts of climate change vary at the local scale and could require different adaptation strategies for different communities and for different sectors of the tourism industry. For example, communities in the northern parts of the Great Lakes may find benefit in a greater diversification of their tourism industries, given that warming temperatures could be beneficial for summer tourism activities, while communities in the southern parts of the Great Lakes may have to find other ways to cope with climate conditions that are less conducive to summer tourism activities. Stakeholder input could also help inform the process of producing scientific information that is useful to policymakers when it comes to tourism sector-related decision making.

  10. Evaluation of groundwater and surface water quality and human risk assessment for trace metals in human settlements around the Bosomtwe Crater Lake in Ghana. (United States)

    Asare-Donkor, Noah Kyame; Boadu, Thomas Asare; Adimado, Anthony Apeke


    Geogenic and anthropogenic activities introduce certain metals into the environment which tend to deteriorate the quality of both surface and groundwater in the Bosomtwe Crater Lake and its surroundings. In this study spatio-temporal variations in concentrations and risk assessment of selected trace metals (As, Fe, Pb, Zn, Cr, Cd and Ni) were investigated during the wet and dry seasons for surface and groundwater in selected human settlements around the lake. The levels of As, Cd and Ni were generally small and were below the detection limit of the instrument. The results showed no significant seasonal variations in the mean levels of Pb, Fe, Zn and Cr in water from the Bosomtwe Crater Lake. The hazard quotients and health hazard indices through ingestion and dermal contact of lake and groundwater in towns around the lake for both adults and children gave values which were below the acceptable limit of less than unity (lake and groundwater from the lake and its surroundings poses carcinogenic risk with regard to the level of Pb and Cr. Hence appropriate control measures and interventions should be put in place to protect the health of the human population in the study area.


    Directory of Open Access Journals (Sweden)

    Moitree TARAN


    Full Text Available Wetland resources are having significant role in the livelihoods of ethnic communities and their involvement in resource management can be used to maintain ecological banance in wetland ecosystem. The objective of this study is to provide some ideas about participation of “Tripuri” community and their role in wetland conservation and management. Physicochemical water parameters of the lake shows suitability of this lake water for fisheries and also its a good storage for carbon. Overall, six genera belonging to four classes of phytoplankton and total four groups of zooplankton have been identified from the lake. Total thirteen aquatic plants belongs to twelve families were identified from Kalyanthakur para lake and most of the plants are used for food, fodder and fencing. The dominant aquatic species were Enhydra fluctuans DC., Sacciolepis sp. and Nymphoides indica (L. Kuntze. with the Importance Value Index (IVI 73.53, 61.58 and 50.00 respectively. The lake also provides various provisioning and cultural services. The provisioning services of the Kalyanthakur para lake includes mainly fishes, aquatic plants, crabs, molluscs, domestic uses, collection of timber and fuelwood with a total value of US$ 26263.65/year. Whereas, the cultural services of Kalyanthakur para lake, includes recreational opportunities, aesthetic value and place with natural beauty with a total value of US$ 2605.68/year. Human settlements, negligence of the concerned authority and public effluent are worked as the chief factors for the degradation of this lake. Government should take some planning, managing and monitoring plan to mitigate the anthropogenic stress on this community based lake.

  12. The Ontario Energy Marketers Association

    Energy Technology Data Exchange (ETDEWEB)

    Baker, W.F.C. [Ontario Energy Marketers Association, ON (Canada)


    An overview of the role of the Ontario Energy Marketers Association (OEMA) and its future orientation was presented. Participants in the OEMA include agents, brokers, marketers, local distribution companies, public interest representatives, associations and government representatives. The role of the OEMA is to encourage open competition for the benefit and protection of all energy consumer and market participants. As well, the OEMA serves as a forum for key industry stakeholders to resolve market issues outside the regulatory arena, set standards and codes of practice, establish customer education programs, and develop industry input into public policy making.

  13. Test Review: Wechsler, D. (2014),"Wechsler Intelligence Scale for Children, Fifth Edition: Canadian 322 (WISC-V[superscript CDN])." Toronto, Ontario: Pearson Canada Assessment. (United States)

    Cormier, Damien C.; Kennedy, Kathleen E.; Aquilina, Alexandra M.


    The Wechsler Intelligence Scale for Children, Fifth Edition: Canadian (WISC-V[superscript CDN]; Wechsler, 2014) is published by Pearson Canada Assessment. The WISC-V[superscript CDN] is a norm-referenced, individually administered intelligence battery that provides a comprehensive diagnostic profile of the cognitive strengths and weaknesses of…

  14. Examining Competition in Ontario's Higher Education Market (United States)

    Farhan, Bayan Yousef


    Financial challenges have forced many publicly funded academic institutions in Ontario to adopt a corporate model and to use market tools to compete in the higher education market and maintain their enrolment and revenue levels. This study has analyzed how competition affects publicly funded universities in Ontario. Competition was examined by…

  15. Libraries in Ontario: MedlinePlus (United States)

    ... this page: Libraries in Ontario To use the sharing features on ... JavaScript. Barrie Royal Victoria Regional Health Centre Health Library 201 Georgian Drive Barrie, ON L4M 6M2 CANADA ...

  16. Using integrated multivariate statistics to assess the hydrochemistry of surface water quality, Lake Taihu basin, China

    Directory of Open Access Journals (Sweden)

    Xiangyu Mu


    Full Text Available Natural factors and anthropogenic activities both contribute dissolved chemical loads to  lakes and streams.  Mineral solubility,  geomorphology of the drainage basin, source strengths and climate all contribute to concentrations and their variability. Urbanization and agriculture waste-water particularly lead to aquatic environmental degradation. Major contaminant sources and controls on water quality can be asssessed by analyzing the variability in proportions of major and minor solutes in water coupled to mutivariate statistical methods.   The demand for freshwater needed for increasing crop production puulation and industrialization occurs almost everywhere in in China and these conflicting needs have led to widespread water contamination. Because of heavy nutrient loadings from all of these sources, Lake Taihu (eastern China notably suffers periodic hyper-eutrophication and drinking water deterioration, which has led to shortages of freshwater for the City of Wuxi and other nearby cities. This lake, the third largest freshwater body in China, has historically beeen considered a cultural treasure of China, and has supported long-term fisheries. The is increasing pressure to remediate the present contamination which compromises both aquiculture and the prior economic base centered on tourism.  However, remediation cannot be effectively done without first characterizing the broad nature of the non-point source pollution. To this end, we investigated the hydrochemical setting of Lake Taihu to determine how different land use types influence the variability of surface water chemistry in different water sources to the lake. We found that waters broadly show wide variability ranging from  calcium-magnesium-bicarbonate hydrochemical facies type to mixed sodium-sulfate-chloride type. Principal components analysis produced three principal components that explained 78% of the variance in the water quality and reflect three major types of water

  17. Assessing the potential for lake bank filtration: mapping shallow aquifers and groundwater flow in a lake with combined offshore geophysical and tracer methods (United States)

    Sebok, Eva; Karan, Sachin; Engesgaard, Peter


    Water extraction from bank-filtration wells bordering rivers and lakes is common practice in water management as surface water bodies provide a continuous supply of water, while the seepage of water through the sediment-water interface provides a physical, chemical and biological filtering of the extracted water. Hence, bank filtration offers a potential for also reducing contaminant concentrations. Tissø is the fourth largest lake in Denmark with a surface area of 12.3 km2 and a water volume of approx. 100 million m3, which is continuously replenished by Halleby stream flowing to the lake in the north with an average annual discharge of 2.4 m3/s. Due to the increasing demand for water resources, the local waterworks, Kalundborg Forsyning, aims to raise the present extraction of 5 million m3/year surface water from Tissø by an additional 5-10 million m3/year. To reduce water treatment costs, bank filtration could potentially be an additional optimal water extraction method around the lake provided that there are shallow aquifers in the area with good hydraulic connection to the lake. The aim of this study is therefore (i) to map the aquifer sediments under the lakebed and on land to locate shallow aquifers and their outcrops in the lake and (ii) to study whether groundwater discharges from these aquifers to the lake indicating good hydraulic connection. A 5 km shoreline at the northern part of the lake was surveyed with offshore geophysical methods to locate shallow aquifers, which could be used for water extraction. Electrical Resistivity Tomography (ERT) with floating electrodes was used to map shallow underwater aquifer sediments along the shoreline, while offshore sediment properties in 200 m long transects perpendicular to the shoreline were surveyed both by ERT and a Ground Penetrating Radar (GPR). Groundwater seepage was studied with thermal and chemical tracers in an area selected based on the geophysical surveys. Samples for water stable isotopes and

  18. Biology and status of the shortnose cisco Coregonus reighardi Koelz in the Laurentian Great Lakes (United States)

    Webb, Shane A.; Todd, Thomas N.


    The shortnose cisco, Coregonus reighardi, a member of the endemic species assemblage of Coregoninae in the Laurentian Great Lakes, was commercially important until overfishing and competition pressures from induced planktivores extirpated the species in Lakes Michigan and Ontario. Spawning shortnose ciscoes have been collected from Lake Huron and Georgian Bay of Lake Huron since 1956, however, no individuals have been collected from these habitats since 1985. Shortnose ciscoes were not collected during surveys of the cisco fishery of Georgian Bay during the summer of 1992 and spring of 1993. The lack of captures in the last eight years coupled with captures of only lone individuals in the last 16 years suggests the species may be extinct in all of the Laurentian system. The life history traits examined for Lake Huron shortnose ciscoes were similar to the conditions recorded for Lake Michigan and Ontario shortnose ciscoes, although Lake Huron fish were smaller.

  19. Water resources management in the urban agglomeration of the Lake Biwa region, Japan: An ecosystem services-based sustainability assessment. (United States)

    Chen, Xiaochen; Chen, Yuqing; Shimizu, Toshiyuki; Niu, Jia; Nakagami, Ken'ichi; Qian, Xuepeng; Jia, Baoju; Nakajima, Jun; Han, Ji; Li, Jianhua


    An innovative ecosystem services-based sustainability assessment was conducted in the important urban agglomeration of the Lake Biwa region, Japan, covering the time period from 1950 to 2014. A 22-indicator system was established that was based on the major ecosystem services of Lake Biwa and its water courses, i.e., provisioning services regarding aquatic products and water; regulating services regarding floods and water quality; cultural services regarding recreation and tourism, scientific research, and environmental education; and supporting services regarding biodiversity. First, changes in the eight ecosystem services were discussed together with the considerable experience and difficult lessons that can be drawn from the development trajectory. Next, with the indicators rearranged according to sustainability principles, the regional sustainability over the past six-plus decades was assessed. In general, this urban agglomeration has been progressing in terms of its sustainability, although economic and social development was achieved at the cost of environmental degradation in the past, and the current economic downturn is hurting the balanced development and integrated benefits. The results lead directly to recommendations for regional development, especially in terms of economic rejuvenation, from the perspective of improving management of Lake Biwa's water resources. Moreover, the relevant knowledge is educational and inspirational for other places in the world that are facing similar development issues. For example, the effective and even pioneering countermeasures that have been taken against environmental degradation, as well as the participation and collaboration of multiple stakeholders, could be useful as a model. Moreover, the study invites increased understanding of ecosystem vulnerability to anthropogenic devastation and emphasizes the priority of precautionary measures over countermeasures in the context of holistic urban planning and sustainable

  20. Risk assessment and chemical fractionation of selected elements in surface sediments from Lake Qarun, Egypt using modified BCR technique. (United States)

    Soliman, Naglaa F; El Zokm, Gehan M; Okbah, Mohamed A


    In this study, spatial distribution and chemical fractionation were conducted to appraise the overall classification of Al, B, Cd, Cr, and Pb as well as their ecological risks in Lake Qarun sediments. Also, the other chemical components (CaCO3, TOC, SO4(2-), SiO3(2-), PO4(3-), F, Ca, and Mg) that represented the chemical composition of the sediments were determined. Modified BCR sequential extraction technique was used to evaluate the four (acid soluble, reducible, oxidizable and residual) fractions of the surface sediments. The association of Cd was found the highest with acid-soluble fraction (12.16-77.42%), while, Al (89.92-96.83%), B (42.32-93.93%), Cr (86.35-97.42%) and Pb (31.98-86.26%) were reside in residual phase. The degree of surface sediment contamination was computed by risk assessment code (RAC), individual contamination factor (ICF) and Global contamination factor (GCF). Risk assessment code classification showed that the relative amounts of easily dissolved phase of the investigated elements in the sediments are in the order of: Cd > Pb > B > Cr > Al. As a result, Cd had the highest risk to Lake Qarun. This study is a first approach of chemical fractionation of Al, B, Cd, Cr, and Pb in one of the most ecologically important Protectorates declared in the framework of Law 102 of year 1983. Information of this study constitutes a baseline of elements fractionation in Lake Qarun sediments and should be used as a reference for future studies on the changes of labile and residual elements fractions over time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Assessing and addressing the re-eutrophication of Lake Erie: central basin hypoxia (United States)

    Scavia, Donald; Allan, J. David; Arend, Kristin K.; Bartell, Steven; Beletsky, Dmitry; Bosch, Nate S.; Brandt, Stephen B.; Briland, Ruth D.; Daloğlu, Irem; DePinto, Joseph V.; Dolan, David M.; Evans, Mary Anne; Farmer, Troy M.; Goto, Daisuke; Han, Haejin; Höök, Tomas O.; Knight, Roger; Ludsin, Stuart A.; Mason, Doran; Michalak, Anna M.; Richards, R. Peter; Roberts, James J.; Rucinski, Daniel K.; Rutherford, Edward; Schwab, David J.; Sesterhenn, Timothy M.; Zhang, Hongyan; Zhou, Yuntao


    Relieving phosphorus loading is a key management tool for controlling Lake Erie eutrophication. During the 1960s and 1970s, increased phosphorus inputs degraded water quality and reduced central basin hypolimnetic oxygen levels which, in turn, eliminated thermal habitat vital to cold-water organisms and contributed to the extirpation of important benthic macroinvertebrate prey species for fishes. In response to load reductions initiated in 1972, Lake Erie responded quickly with reduced water-column phosphorus concentrations, phytoplankton biomass, and bottom-water hypoxia (dissolved oxygen 2) requires cutting total phosphorus loads by 46% from the 2003–2011 average or reducing dissolved reactive phosphorus loads by 78% from the 2005–2011 average. Reductions to these levels are also protective of fish habitat. We provide potential approaches for achieving those new loading targets, and suggest that recent load reduction recommendations focused on western basin cyanobacteria blooms may not be sufficient to reduce central basin hypoxia to 2000 km2.

  2. Assessment of water-quality data from Long Lake National Wildlife Refuge, North Dakota--2008 through 2012 (United States)

    Tangen, Brian A.; Finocchiaro, Raymond G.; Gleason, Robert A.; Rabenberg, Michael J.; Dahl, Charles F.; Ell, Mike J.


    ong Lake National Wildlife Refuge, located in south-central North Dakota, is an important habitat for numerous migratory birds and waterfowl, including several threatened or endangered species. The refuge is distinguished by Long Lake, which is approximately 65 square kilometers and consists of four primary water management units. Water levels in the Long Lake units are maintained by low-level dikes and water-control structures, which after construction during the 1930s increased the water-storage capacity of Long Lake and reduced the frequency and volume of flushing flows downstream. The altered water regime, along with the negative precipitation:evaporation ratio of the region, may be contributing to the accumulation of water-borne chemical constituents such as salts, trace metals, and other constituents, which at certain threshold concentrations may impair aquatic plant, invertebrate, and bird communities of the refuge. The refuge’s comprehensive conservation planning process identified the need for water-quality monitoring to assess current (2013) conditions, establish comparative baselines, evaluate changes over time (trends), and support adaptive management of the wetland units. In 2008, the U.S. Geological Survey, U.S. Fish and Wildlife Service, and North Dakota Department of Health began a water-quality monitoring program at Long Lake National Wildlife Refuge to address these needs. Biweekly water-quality samples were collected for ions, trace metals, and nutrients; and in situ sensors and data loggers were installed for the continuous measurement of specific conductance and water depth. Long Lake was characterized primarily by sodium, bicarbonate, and sulfate ions. Overall results for total alkalinity and hardness were 580 and 329 milligrams per liter, respectively; thus, Long Lake is considered alkaline and classified as very hard. The mean pH and sodium adsorption ratio for Long Lake were 8.8 and 10, respectively. Total dissolved solids concentrations

  3. Using Fiber Optic Distributed Temperature Sensing (DTS) to Assess Groundwater-Lake Exchange in an Acid Mine Lake in Eastern Germany (United States)

    Hausner, M. B.; Fleckenstein, J.; Neumann, C.; Tyler, S. W.


    Groundwater flows through contaminated mine sites are a major concern in many parts of the world. In this study, a variety of instrumentation was used to locate and quantify groundwater inflows into an acid lake on an abandoned mine site in Brandenburg, Germany. While previously-installed piezometers and seepage meters had identified several points of groundwater influx into the lake, such techniques are spatially limited to the point of installation. To address this limitation, a fiber-optic distributed temperature sensor (DTS) was deployed across the lake bottom and in vertical profilers to confirm and expand the previously generated data sets. Fiber-optic DTS, a relatively new technology, provides the opportunity to measure temperature on very high spatial and temporal scales using Raman spectra scattering of pulsed light within a glass fiber. A 1000 meter cable was deployed spatially along the sediment-water interface to identify spatially scattered areas of groundwater inflow, while two high-resolution probes (which return temperature readings every 2.4 vertical cm) were installed vertically near existing seepage meters. Preliminary analysis of the vertical deployments showed substantial groundwater upwelling, confirming the results of previous seepage meter measurements which showed significant vertical flux into the lake. Ongoing analysis of the lateral deployment is expected to identify areas in which there are anomalies in the diurnal temperature cycle at the lake bottom; such anomalies may indicate groundwater influx into the lake. These areas will be used to locate future seepage meter and piezometer installations.

  4. Assessment of metals pollution in the sediments of lake burullus, s.e. Mediterranean, egypt


    El Sammak, A.A. [عمرو عبدالعزيز السماك; El-Sabrouti, M. A.


    The present study aims to quantify the heavy metals contents in the sediments of Lake Burullus. Cu, Pb, Zn, and Cd were analyzed using ICP spectrometer. The contamination factors (CF) were calculated for each element. The CFs were found to fall in the following sequence : Cd > Pb > Cu > Zn. The pollution load index (PLI) was also estimated. Chcrnoff face analysis was used to represent the pollution extent at different stations. The level of pollution by heavy metals is mainly induced by the i...

  5. Accumulation and risk assessment of heavy metals in sediments and zoobenthos (Bellamya aeruginosa and Corbicula fluminea) from Lake Taihu. (United States)

    Kong, Ming; Hang, Xiaoshuai; Wang, Longmian; Yin, Hongbin; Zhang, Yimin


    Accumulation and risk assessment of metals in sediments and zoobenthos (Bellamya aeruginosa and Corbicula fluminea) from Lake Taihu were studied. Results showed that metal (Cr, Cd, Cu, Zn, Pb and Ni) concentrations in Lake Taihu varied greatly, and Cd in the Zhushan Bay showed higher bioavailability compared to the other metals studied. The spatial distribution of metals in B. aeruginosa and C. fluminea was similar to that in sediments. Zn and Cu exhibited the higher mean concentration in B. aeruginosa and C. fluminea, which was in good accordance with its higher content in surrounding sediment. Labile fractions (i.e., acid-soluble (F1), reducible (F2) and F1+F2) of Cu and Zn in sediments showed a significant positive correlation with them in B. aeruginosa (Pfluminea and in sediments. The results of ecological risk assessment showed that Zhushan Bay was seriously contaminated by metal Cd, as it made the main contribution of all the metals. Total target hazard quotients indicated that adults and children both had potential health risk through consuming C. fluminea. Hazard index values suggested that adults and children might experience adverse health effects through consuming B. aeruginosa and C. fluminea.

  6. An Integrated Approach To Offshore Wind Energy Assessment: Great Lakes 3D Wind Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R. J. [Cornell Univ., Ithaca, NY (United States). Sibley School of Mechanical & Aerospace Engineering; Pryor, S. C. [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences


    This grant supported fundamental research into the characterization of flow parameters of relevance to the wind energy industry focused on offshore and the coastal zone. A major focus of the project was application of the latest generation of remote sensing instrumentation and also integration of measurements and numerical modeling to optimize characterization of time-evolving atmospheric flow parameters in 3-D. Our research developed a new data-constrained Wind Atlas for the Great Lakes, and developed new insights into flow parameters in heterogeneous environments. Four experiments were conducted during the project: At a large operating onshore wind farm in May 2012; At the National Renewable Energy Laboratory National Wind Technology Center (NREL NWTC) during February 2013; At the shoreline of Lake Erie in May 2013; and At the Wind Energy Institute of Canada on Prince Edward Island in May 2015. The experiment we conducted in the coastal zone of Lake Erie indicated very complex flow fields and the frequent presence of upward momentum fluxes and resulting distortion of the wind speed profile at turbine relevant heights due to swells in the Great Lakes. Additionally, our data (and modeling) indicate the frequent presence of low level jets at 600 m height over the Lake and occasions when the wind speed profile across the rotor plane may be impacted by this phenomenon. Experimental data and modeling of the fourth experiment on Prince Edward Island showed that at 10-14 m escarpment adjacent to long-overseas fetch the zone of wind speed decrease before the terrain feature and the increase at (and slightly downwind of) the escarpment is ~3–5% at turbine hub-heights. Additionally, our measurements were used to improve methods to compute the uncertainty in lidar-derived flow properties and to optimize lidar-scanning strategies. For example, on the basis of the experimental data we collected plus those from one of our research partners we advanced a new methodology to

  7. Suvemaja, Antler Island, Fairy Lake, Ontario / Ants Elken

    Index Scriptorium Estoniae

    Elken, Ants, 1917-2012


    Tuli projekteerida suvila kasvavale perele, mis algusest peale kasutamiskõlblikuna areneks koos perekonna laienemisega. Kerged paviljonid meenutavad küla. Ehitati 1966-1989. Arhitekt Elmar Tampõld. Joonised, vaated.

  8. Lake Ontario Shore Protection Study: Literature Review Report. (United States)



  9. National Assessment of Historical Shoreline Change: A Pilot Study of Historical Coastal Bluff Retreat in the Great Lakes, Erie, Pennsylvania (United States)

    Hapke, Cheryl J.; Malone, Shamus; Kratzmann, Meredith G.


    Coastal bluff retreat is a chronic problem along many high-relief coastlines in the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regard-ing trends and rates of bluff retreat. There is also a need for a comprehensive analysis that is consistent from one coastal region to another. To address these national needs, the U.S. Geological Survey (USGS), as part of the National Assessment of Coastal Change Hazards Project, conducted a pilot study of bluff retreat along the Lake Erie, Pa., coastline to assess the feasibility of undertaking a larger, multi-state analysis in the Great Lakes region. This report provides an overview of the pilot-study location and bluff geomorphology, the data sources and methodology, results of the analysis, and a discussion of the feasibility of undertaking a similar analysis along eroding bluffs in other Great Lakes states. This pilot study is part of an ongoing effort by the USGS to provide a comprehensive analysis of historical shoreline change and cliff and bluff retreat along open-ocean coastlines of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of the work is to develop standard, repeatable methods for mapping and analyzing coastal change so that systematic and consistent periodic updates of coastal erosion can be made nationally. Bluff-retreat evaluations are conducted by comparing the location of a historical bluff edge digitized from aerial photographs with those of recent bluff edges interpreted from both aerial photographs and lidar topographic surveys. The historical bluff edge is from 1938, whereas the more recent bluff edges are from 1998 and 2006 lidar data. Long-term (68-year) rates of retreat are calculated using the available bluff-edge data. The rates of retreat presented in this report represent conditions from the 1930s to 1998/2006, and are not intended for


    Directory of Open Access Journals (Sweden)

    Denisa Mariana DAN


    Full Text Available One of the three strategic objectives of the Europe 2020 Agenda is to ensure the sustainable management of the natural resources and to fight against climate changes. Considering water to be not only a valuable natural resource for any type of landscape, but also the vital environmental component that ensured a minimum of productivity for the people working the unproductive salinization and gleyzation affected soils in the Jiu-Corabia enclosure, using embankment dams to breake the link between the Danube and the flood organism it created over a timespan of millenia has proven in the last 50 years to be an economic and ecological failure. Since the December 1989 events in Romania, after most of the socialist institutions have proven to be too resource consuming, thus unprofitable or maladaptive, the Jiu-Corabia locals have individually experimented with various land cultivation patterns, all of them based on draught-resistant crops, such as peanuts. In spite of it being the original natural landuse, lake usage has only been scarcely mentioned as a project after the 2006 flood, but after being institutionally rejected, its benefits in terms of ecological restoration, financial productivity have not been further looked into. The current article aims to identify different height level scenarios of lake usage in the Jiu-Corabia enclosure, using GIS technique. Lake volumes are calculated for each scenario with the aim of assessing the volume of water this enclose can absorb during flooding periods, as well as of estimating fish production for when the waters are low and it is not needed as a controlled flood chamber. Other benefits, such as providing a source of humidity for precipitations which will aid the crops nearby, have not been monetized, but contribute to the regional development efforts.

  11. Baseline risk assessment of ground water contamination at the uranium mill tailings site Salt Lake City, Utah

    Energy Technology Data Exchange (ETDEWEB)


    This baseline risk assessment of groundwater contamination at the uranium mill tailings site near Salt Lake City, Utah, evaluates potential public health or environmental impacts resulting from ground water contamination at the former uranium ore processing site. The tailings and other contaminated material at this site were placed in a disposal cell located at Clive, Utah, in 1987 by the US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project. The second phase of the UMTRA Project is to evaluate residual ground water contamination at the former uranium processing site, known as the Vitro processing site. This risk assessment is the first site-specific document under the Ground Water Project. It will help determine the appropriate remedial action for contaminated ground water at the site.

  12. Keystone Organization for Ontario's Open Source Ecosystem

    Directory of Open Access Journals (Sweden)

    Rowland Few


    Full Text Available Many companies, individuals and organizations in Ontario produce and use open source assets and processes to provide unique value to their customers, clients, and themselves. To better enable these companies, individuals and organizations to (i co-evolve capabilities and roles, (ii align themselves with companies holding leadership roles, and (iii invest in shared visions, the Talent First Network (TFN has become the keystone organization of Ontario's open source ecosystem. This article introduces the TFN and identifies the steps it is taking to better support the Ontario Open Source Ecosystem.

  13. The Risk Assessment of Sediment Heavy Metal Pollution in the East Dongting Lake Wetland


    Cong Hu; Zheng-miao Deng; Yong-hong Xie; Xin-sheng Chen; Feng Li


    Total concentrations of cadmium (Cd), lead (Pb), chrome (Cr), and nickel (Ni) in surface sediment (0–10 cm) from the East Dongting Lake wetlands were determined and the spatial distribution of heavy metals was mapped. The results showed that the single risk indices (Eri) of heavy metals were ranked in the order of Cd > Pb > Ni > Cr. The content of Cd and Pb was gradually reduced from the east (Xiangjiang River) to the west, while the Cr and Ni content had a patchy distribution pattern in the ...

  14. Patterns of surgical care for uterine cancers in Ontario. (United States)

    Elit, L; Schultz, S; Prysbysz, R; Kwon, J; Saskin, R; Gunraj, N; Wilton, A S; Simunovic, M; Urbach, D


    To facilitate the planning of future resources for cancer services in Ontario, Cancer Care Ontario commissioned an evaluation of operative services delivered for uterine cancer. Women with an incident diagnosis of a uterine malignancy were identified from 1 April 2003 to 31 March 2004 using the Ontario Cancer Registry. Record linkages were created to other provincial health databases such as the Ontario Health Insurance Plan. Uterine cancer affected 1,436 women. Disease specific rates of cancer were higher in rural areas and those from the highest income quintiles. Surgery occurred in 94.7% of women. Use of surgery did not appear to vary by SEC, urban/rural residence or LHIN. Gynecologists conducted 76.1% of the operations. Lymphadenectomy took place in 18.7% of women. Lymphadenectomy rates were highest in gynecologic oncologists (43.3%). All women were assessed by CXR. Radiation therapy consults were preformed in half of the women with uterine cancer but treatment was only delivered in half of those seen. Medical oncologists saw about 6.3% of women with uterine cancers. There appear to be variations in incidence rates of uterine cancer with disease being more frequent in those of the highest SES. In two-thirds of the population, surgery is delivered in the region where the patient lives. Subspecialty care from gynecologic oncologists was provided to one-third of women. Rates of lymphadenectomy as part of a surgical attempt to assess disease spread appear low. These pilot data would be enhanced with further information such as comorbidity, treatment intent (palliative/curative), histology, grade and stage.

  15. Glacial lake inventory and lake outburst potential in Uzbekistan. (United States)

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus


    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m2. As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Comparative assessment of diet and condition factor of Cyprinus carpio and Oreochromis leucostictus in Lake Naivasha, Kenya

    Directory of Open Access Journals (Sweden)

    James Last Keyombe


    Full Text Available The study compared and assessed the diet and condition factors of two fish species, Oreochromis leucostictus and Cyprinus carpio, in Lake Naivasha. Fish samples were collected monthly using gill nets (35-70 mm mesh size from July to December 2013. Stomach contents of all the specimens were analysed using the point method. Results indicated that detritus was the most abundant food item in the diet of both O. leucostictus and C. carpio accounting for 50% and 63%, respectively, while benthic macroinvertebrates contributed the least with each fish having 2%. Rooting and digging behaviour of the carp probably led to both C. carpio and O. leucostictus ingesting the suspended detritus as their main source of food with C. carpio outcompeting O. leucostictus due to its prolific nature and better adaptability to benthic conditions. Fulton’s condition factor of all the fish samples had values of >1. A comparison of the two fish species showed C. carpio had a condition factor of 1.51 while O. leucostictus had 1.32. The higher condition factor of C. carpio in Lake Naivasha is an indication that the fish have better tissue energy reserves, greater reproductive potential and higher survival rates compared to O. leucostictus with a lower condition factor.

  17. The Risk Assessment of Sediment Heavy Metal Pollution in the East Dongting Lake Wetland

    Directory of Open Access Journals (Sweden)

    Cong Hu


    Full Text Available Total concentrations of cadmium (Cd, lead (Pb, chrome (Cr, and nickel (Ni in surface sediment (0–10 cm from the East Dongting Lake wetlands were determined and the spatial distribution of heavy metals was mapped. The results showed that the single risk indices (Eri of heavy metals were ranked in the order of Cd > Pb > Ni > Cr. The content of Cd and Pb was gradually reduced from the east (Xiangjiang River to the west, while the Cr and Ni content had a patchy distribution pattern in the East Dongting Lake wetlands. Cd and Pb contents were correlated with soil pH significantly, while Cr and Ni contents were correlated with soil organic carbon (SOC and total nitrogen (TN. The origination of heavy metal (Cd, Cr, Ni, and Pb could be divided into two groups: Cd and Pb from anthropogenic source and Cr and Ni from parent material weathering. Our results indicated that Cd posed a high risk to local ecosystem. The relatively lower pH and higher soil organic carbon (SOC and total nitrogen (TN in sediment may inhibit the fixation of heavy metals, which in turn increased the concentration of heavy metal in sediment.

  18. Services available to sight-impaired and legally blind patients in Ontario: the Ontario model. (United States)

    Lapointe, Marie Louise


    The Participation and Activity Limitation Survey undertaken by Statistics Canada in 2001 identified 635,000 Canadians who have a seeing disability. By 2015 these numbers are expected to double, with the largest group of patients residing in Ontario, the province with the largest population. Ontario has a long-established history of vision rehabilitation, but recent demographic changes and an ever-increasing older population have made the planning of vision rehabilitation services in Ontario (as in the rest of Canada) even more urgent. The intent of this paper is to present the variety of services currently available to the visually impaired in Ontario.

  19. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex (United States)

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.


    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.

  20. Coupled impacts of climate and land use change across a river-lake continuum: insights from an integrated assessment model of Lake Champlain’s Missisquoi Basin, 2000-2040 (United States)

    Zia, Asim; Bomblies, Arne; Schroth, Andrew W.; Koliba, Christopher; Isles, Peter D. F.; Tsai, Yushiou; Mohammed, Ibrahim N.; Bucini, Gabriela; Clemins, Patrick J.; Turnbull, Scott; Rodgers, Morgan; Hamed, Ahmed; Beckage, Brian; Winter, Jonathan; Adair, Carol; Galford, Gillian L.; Rizzo, Donna; Van Houten, Judith


    Global climate change (GCC) is projected to bring higher-intensity precipitation and higher-variability temperature regimes to the Northeastern United States. The interactive effects of GCC with anthropogenic land use and land cover changes (LULCCs) are unknown for watershed level hydrological dynamics and nutrient fluxes to freshwater lakes. Increased nutrient fluxes can promote harmful algal blooms, also exacerbated by warmer water temperatures due to GCC. To address the complex interactions of climate, land and humans, we developed a cascading integrated assessment model to test the impacts of GCC and LULCC on the hydrological regime, water temperature, water quality, bloom duration and severity through 2040 in transnational Lake Champlain’s Missisquoi Bay. Temperature and precipitation inputs were statistically downscaled from four global circulation models (GCMs) for three Representative Concentration Pathways. An agent-based model was used to generate four LULCC scenarios. Combined climate and LULCC scenarios drove a distributed hydrological model to estimate river discharge and nutrient input to the lake. Lake nutrient dynamics were simulated with a 3D hydrodynamic-biogeochemical model. We find accelerated GCC could drastically limit land management options to maintain water quality, but the nature and severity of this impact varies dramatically by GCM and GCC scenario.

  1. A multi-temporal analysis for change assessment and estimation of algal bloom in Sambhar Lake, Rajasthan, India. (United States)

    Vijay, Ritesh; Pinto, Shannon M; Kushwaha, Vikash K; Pal, Sukdeb; Nandy, Tapas


    Sambhar Lake in Rajasthan, India is the major inland salt water lake producing salt for centuries. The present study addresses the monitoring changes in and around the lake and its consequent effect on the lake water ecology. For this, satellite images of the years 1976, 1981, 1997, and 2013 are analyzed for land use land cover classes. Significant reduction in the water body is observed in contrast with the increase in salt pan around the periphery of lake and wetland classes. Further, the extent of water body and algae in the lake are delineated as per normalized difference water index and normalized difference vegetation index. Rainfall data do not indicate any major change in the pattern, but drastic decrease in the extent of water body and significant increase in algal bloom are serious concerns for the lake's existence. This may be due to surrounding anthropogenic activities and construction of check dams and anicuts in the lake catchment which curtail the runoff into the lake and provide favorable growth of algae. Sambhar Lake, being declared as a wetland according to the Ramsar Convention, is necessary to protect and conserve the ecological importance of the lake through sustainable planning and management.

  2. Western Ontario: Waterfowl breeding population survey: 1986 (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes the Waterfowl Breeding Population and Habitat Survey for western Ontario during 1986. The primary purpose of the survey is to provide...

  3. Trio Estonia esineb Lõuna-Ontarios

    Index Scriptorium Estoniae


    Lõuna-Ontario muusikahuvilistel on tänu Eesti Sihtkapitalile Kanadas ja Cathedral Bluffs sümfooniaorkestrile harukordne võimalus saada oktoobrikuus osa kõrgetasemelise Trio Estonia musitseerimisest

  4. Expanding Scope of Practice for Ontario Optometrists

    National Research Council Canada - National Science Library

    Emily Bray; Ivy Bourgault


    In 2011, The Optometry Act, 1991 was amended to include The Designated Drugs and Standards of Practice Regulation which expanded the scope of practice for Ontario optometrists to include prescribing...

  5. Potential Effects of Climate Changes on Aquatic Systems: Laurentian Great Lakes and Precambrian Shield Region (United States)

    Magnuson, J. J.; Webster, K. E.; Assel, R. A.; Bowser, C. J.; Dillon, P. J.; Eaton, J. G.; Evans, H. E.; Fee, E. J.; Hall, R. I.; Mortsch, L. R.; Schindler, D. W.; Quinn, F. H.


    The region studied includes the Laurentian Great Lakes and a diversity of smaller glacial lakes, streams and wetlands south of permanent permafrost and towards the southern extent of Wisconsin glaciation. We emphasize lakes and quantitative implications. The region is warmer and wetter than it has been over most of the last 12000 years. Since 1911 observed air temperatures have increased by about 0·11°C per decade in spring and 0·06°C in winter; annual precipitation has increased by about 2·1% per decade. Ice thaw phenologies since the 1850s indicate a late winter warming of about 2·5°C. In future scenarios for a doubled CO2 climate, air temperature increases in summer and winter and precipitation decreases (summer) in western Ontario but increases (winter) in western Ontario, northern Minnesota, Wisconsin and Michigan. Such changes in climate have altered and would further alter hydrological and other physical features of lakes. Warmer climates, i.e. 2 × CO2 climates, would lower net basin water supplies, stream flows and water levels owing to increased evaporation in excess of precipitation. Water levels have been responsive to drought and future scenarios for the Great Lakes simulate levels 0·2 to 2·5 m lower. Human adaptation to such changes is expensive. Warmer climates would decrease the spatial extent of ice cover on the Great Lakes; small lakes, especially to the south, would no longer freeze over every year. Temperature simulations for stratified lakes are 1-7°C warmer for surface waters, and 6°C cooler to 8°C warmer for deep waters. Thermocline depth would change (4 m shallower to 3·5 m deeper) with warmer climates alone; deepening owing to increases in light penetration would occur with reduced input of dissolved organic carbon (DOC) from dryer catchments. Dissolved oxygen would decrease below the thermocline. These physical changes would in turn affect the phytoplankton, zooplankton, benthos and fishes. Annual phytoplankton production may

  6. Preliminary volcano hazard assessment for the Emmons Lake volcanic center, Alaska (United States)

    Waythomas, Christopher; Miller, Thomas P.; Mangan, Margaret T.


    The Emmons Lake volcanic center is a large stratovolcano complex on the Alaska Peninsula near Cold Bay, Alaska. The volcanic center includes several ice- and snow-clad volcanoes within a nested caldera structure that hosts Emmons Lake and truncates a shield-like ancestral Mount Emmons edifice. From northeast to southwest, the main stratovolcanoes of the center are: Pavlof Sister, Pavlof, Little Pavlof, Double Crater, Mount Hague, and Mount Emmons. Several small cinder cones and vents are located on the floor of the caldera and on the south flank of Pavlof Volcano. Pavlof Volcano, in the northeastern part of the center, is the most historically active volcano in Alaska (Miller and others, 1998) and eruptions of Pavlof pose the greatest hazards to the region. Historical eruptions of Pavlof Volcano have been small to moderate Strombolian eruptions that produced moderate amounts of near vent lapilli tephra fallout, and diffuse ash plumes that drifted several hundreds of kilometers from the vent. Cold Bay, King Cove, Nelson Lagoon, and Sand Point have reported ash fallout from Pavlof eruptions. Drifting clouds of volcanic ash produced by eruptions of Pavlof would be a major hazard to local aircraft and could interfere with trans-Pacific air travel if the ash plume achieved flight levels. During most historical eruptions of Pavlof, pyroclastic material erupted from the volcano has interacted with the snow and ice on the volcano producing volcanic mudflows or lahars. Lahars have inundated most of the drainages heading on the volcano and filled stream valleys with variable amounts of coarse sand, gravel, and boulders. The lahars are often hot and would alter or destroy stream habitat for many years following the eruption. Other stratocones and vents within the Emmons Lake volcanic center are not known to have erupted in the past 300 years. However, young appearing deposits and lava flows suggest there may have been small explosions and minor effusive eruptive activity

  7. Modeling five Great Lakes ice-circulation system using an unstructured-grid coupled model (United States)

    Wang, J.


    An unstructured Finite Volume Coastal Ocean Model was modified by replacing the Euler forward scheme with the centered differencing scheme, and applied to all five Great Lakes simultaneously to simulate circulation and thermal structure from 1993 to 2008. Model results are compared to available observations of currents and temperature and previous modeling work. Maps of climatological circulation for all the five Great lakes were presented. Winter currents show a two-gyre type circulation Lakes Ontario and Erie and one large-scale cyclonic circulation in Lakes Michigan, Huron, and Superior. During the summer, a cyclonic circulation remains in Lakes Superior; a primarily cyclonic circulation dominates the upper and central Lake Huron; Lake Ontario turns to have a single cyclonic circulation, while circulation in the central basin of Lake Erie remains two-gyre type; Lake Michigan has a cyclonic gyre in the north and an anti-cyclonic one in the south. The temperature profile during the summer is well simulated when a surface wind-wave mixing scheme is included in the model. Main features of the seasonal evolution of water temperature, such as reverse stratification during the winter, the spring and autumn overturn, the thermal bar, and the stratification during summer are well reproduced. The lakes exhibit significant annual and interannual variations in current speed and temperature. The model successfully reproduced seasonal cycle of lake ice cover, the lake-wide mean surface temperature and lake circulation.

  8. The importance of spatial variation of benthic invertebrates for the ecological assessment of European lakes

    DEFF Research Database (Denmark)

    Solimini, Angelo G.; Sandin, Leif Leonard


    variability. However, littoral and profundal invertebrate communities are constrained by different drivers of change and may respond unevenly to distinct human disturbances. How human disturbances determined by different pressures interact in modifying the distribution of benthic invertebrate species......, funded by the European Union under the 7th Framework Programme), we collated several case studies with the aim to increase our understanding of basic sources of spatial variation of invertebrate assemblages. The set of papers includes a variety of different European lakes, habitat types and human...... pressures from the Nordic, Central, Atlantic, Alpine and Mediterranean regions. All papers have an obvious applied objective and suggest which factors need to be considered when designing invertebrate-based classification tools....

  9. A pesticide monitoring survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment. (United States)

    Papadakis, Emmaluel N; Vryzas, Zisis; Kotopoulou, Athena; Kintzikoglou, Katerina; Makris, Konstantinos C; Papadopoulou-Mourkidou, Euphemia


    A pesticide monitoring study covering the main rivers and lakes of Northern Greece (Macedonia, Thrace and Thessaly) was undertaken. A total of 416 samples were collected over a 1.5-year sampling period (September 1999- February 2001) from six rivers and ten lakes. The water samples were analyzed with an off-line solid phase extraction technique coupled with a gas chromatography ion trap mass spectrometer using an analytical method for 147 pesticides and their metabolites, including organochlorines, organophosphates, triazines, chloroacetanilides, pyrethroids, carbamates, phthalimides and other pesticides (herbicides, insecticides and fungicides). Based on the pesticide survey results, a human health carcinogenic and non-carcinogenic risk assessment was conducted for adults and children. Ecotoxicological risk assessment was also conducted using default endpoint values and the risk quotient method. Results showed that the herbicides metolachlor, prometryn, alachlor and molinate, were the most frequently detected pesticides (29%, 12.5%, 12.5% and 10%, respectively). They also exhibited the highest concentration values, often exceeding 1 μg/L. Chlorpyrifos ethyl was the most frequently detected insecticide (7%). Seasonal variations in measured pesticide concentrations were observed in all rivers and lakes. The highest concentrations were recorded during May-June period, right after pesticide application. Concentrations of six pesticides were above the maximum allowable limit of 0.1 μg/L set for drinking water. Alachlor, atrazine and a-HCH showed unacceptable carcinogenic risk estimates (4.5E-06, 4.6E-06 and 1.3E-04, respectively). Annual average concentrations of chlorpyriphos ethyl (0.031 μg L), dicofol (0.01 μg/L), dieldrin (0.02 μg/L) and endosulfan a (0.065 μg/L) exceeded the EU environmental quality standards. The risk quotient estimates for the insecticides chorpyrifos ethyl, diazinon and parathion methyl and herbicide prometryn were above acceptable risk

  10. Development of a Bi-National Great Lakes Coastal Wetland and Land Use Map Using Three-Season PALSAR and Landsat Imagery

    Directory of Open Access Journals (Sweden)

    Laura Bourgeau-Chavez


    Full Text Available Methods using extensive field data and three-season Landsat TM and PALSAR imagery were developed to map wetland type and identify potential wetland stressors (i.e., adjacent land use for the United States and Canadian Laurentian coastal Great Lakes. The mapped area included the coastline to 10 km inland to capture the region hydrologically connected to the Great Lakes. Maps were developed in cooperation with the overarching Great Lakes Consortium plan to provide a comprehensive regional baseline map suitable for coastal wetland assessment and management by agencies at the local, tribal, state, and federal levels. The goal was to provide not only land use and land cover (LULC baseline data at moderate spatial resolution (20–30 m, but a repeatable methodology to monitor change into the future. The prime focus was on mapping wetland ecosystem types, such as emergent wetland and forested wetland, as well as to delineate wetland monocultures (Typha, Phragmites, Schoenoplectus and differentiate peatlands (fens and bogs from other wetland types. The overall accuracy for the coastal Great Lakes map of all five lake basins was 94%, with a range of 86% to 96% by individual lake basin (Huron, Ontario, Michigan, Erie and Superior.

  11. Using a morpho-functional approach to assess phytoplankton dynamics in two adjacent high-mountain lakes: a 10-year survey

    Directory of Open Access Journals (Sweden)

    Renata Trevisan


    Full Text Available Colbricon Superiore and Inferiore are two small adjacent high-mountain lakes located in the Paneveggio Natural Park (Italy. The lakes differ by size and depth while sharing the same bedrock setting and catchment basin. Changes in the phytoplankton communities were studied over a 10-years period to individuate which environmental variables would determine the main differences in biotic assemblages across time and between the two lakes.The study was conducted with fortnightly samplings, assessing the density and biomass of algal taxa. Relationships of each of the biological variables with water temperature, pH, conductivity, transparency, water level, previous week rainfall, and relative water column stability were analyzed by correlation and regression analyses, cluster analysis, and by canonical correspondence analysis. The most significant variables resulted air temperature, hydrologic water level and pH. The smaller Colbricon Inferiore had about double the amount of phytoplankton density and biomass than did the larger Colbricon Superiore. The same lake had higher diversity and lower evenness in structure of the phytoplankton community. Notwithstanding their proximity each lake appears to follow independent species composition dynamics, however parallel patterns were interestingly revealed when data were analyzed by pooling taxa into morpho-functional groups. Morpho-functional groups (MFGs 1b, 3a, 6b, 7a, 9b were differentially most abundant in warm periods, while 2c, 3b, 11c, 5e, 10a prevailed in cold years. MFGs 1b, 2d, 3a and 3b were more characteristic of Lake Colbricon Superiore, while Colbricon Inferiore preferentially featured MFGs 5a, 5e, 9a, 9b, 10a, 11a and 8a. The role of the meteo-climatic parameters was pointed out in driving the different patterns observed in the two lakes.

  12. The potential of high-frequency profiling to assess vertical and seasonal patterns of phytoplankton dynamics in lakes: An extension of the Plankton Ecology Group (PEG) model (United States)

    Brentrup, Jennifer A.; Williamson, Craig E.; Colom-Montero, William; Eckert, Werner; de Eyto, Elvira; Grossart, Hans-Peter; Huot, Yannick; Isles, Peter D. F.; Knoll, Lesley B.; Leach, Taylor H.; McBride, Christopher G.; Pierson, Don; Pomati, Francesco; Read, Jordan S.; Rose, Kevin C.; Samal, Nihar R.; Staehr, Peter A.; Winslow, Luke A.


    The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence (ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3 methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3) profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean water column data. Contrary to the PEG model’s proposed negligible role for physical control of phytoplankton during the growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus, an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.

  13. Genetic analysis across different spatial scales reveals multiple dispersal mechanisms for the invasive hydrozoan Cordylophora in the Great Lakes. (United States)

    Darling, John A; Folino-Rorem, Nadine C


    Discerning patterns of post-establishment spread by invasive species is critically important for the design of effective management strategies and the development of appropriate theoretical models predicting spatial expansion of introduced populations. The globally invasive colonial hydrozoan Cordylophora produces propagules both sexually and vegetatively and is associated with multiple potential dispersal mechanisms, making it a promising system to investigate complex patterns of population structure generated throughout the course of rapid range expansion. Here, we explore genetic patterns associated with the spread of this taxon within the North American Great Lakes basin. We collected intensively from eight harbours in the Chicago area in order to conduct detailed investigation of local population expansion. In addition, we collected from Lakes Michigan, Erie, and Ontario, as well as Lake Cayuga in the Finger Lakes of upstate New York in order to assess genetic structure on a regional scale. Based on data from eight highly polymorphic microsatellite loci we examined the spatial extent of clonal genotypes, assessed levels of neutral genetic diversity, and explored patterns of migration and dispersal at multiple spatial scales through assessment of population level genetic differentiation (pairwise F(ST) and factorial correspondence analysis), Bayesian inference of population structure, and assignment tests on individual genotypes. Results of these analyses indicate that Cordylophora populations in this region spread predominantly through sexually produced propagules, and that while limited natural larval dispersal can drive expansion locally, regional expansion likely relies on anthropogenic dispersal vectors.

  14. Soil erosion risk assessment using interviews, empirical soil erosion modeling (RUSLE) and fallout radionuclides in a volcanic crater lake watershed subjected to land use change, western Uganda (United States)

    De Crop, Wannes; Ryken, Nick; Tomma Okuonzia, Judith; Van Ranst, Eric; Baert, Geert; Boeckx, Pascal; Verschuren, Dirk; Verdoodt, Ann


    Population pressure results in conversion of natural vegetation to cropland within the western Ugandan crater lake watersheds. These watersheds however are particularly prone to soil degradation and erosion because of the high rainfall intensity and steep topography. Increased soil erosion losses expose the aquatic ecosystems to excessive nutrient loading. In this study, the Katinda crater lake watershed, which is already heavily impacted by agricultural land use, was selected for an explorative study on its (top)soil characteristics - given the general lack of data on soils within these watersheds - as well as an assessment of soil erosion risks. Using group discussions and structured interviews, the local land users' perceptions on land use, soil quality, soil erosion and lake ecology were compiled. Datasets on rainfall, topsoil characteristics, slope gradient and length, and land use were collected. Subsequently a RUSLE erosion model was run. Results from this empirical erosion modeling approach were validated against soil erosion estimates based on 137Cs measurements.

  15. Role of Climate Variability and Human Activity on Poopó Lake Droughts between 1990 and 2015 Assessed Using Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Frédéric Satgé


    Full Text Available In 2015, an emergency state was declared in Bolivia when Poopó Lake dried up. Climate variability and the increasing need for water are potential factors responsible for this situation. Because field data are missing over the region, no statements are possible about the influence of mentioned factors. This study is a preliminary step toward the understanding of Poopó Lake drought using remote sensing data. First, atmospheric corrections for Landsat (FLAASH and L8SR, seven satellite derived indexes for extracting water bodies, MOD16 evapotranspiration, PERSIANN-CDR and MSWEP rainfall products potentiality were assessed. Then, the fluctuations of Poopó Lake extent over the last 26 years are presented for the first time jointly, with the mean regional annual rainfall. Three main droughts are highlighted between 1990 and 2015: two are associated with negative annual rainfall anomalies in 1994 and 1995 and one associated with positive annual rainfall anomaly in 2015. This suggests that other factors than rainfall influenced the recent disappearance of the lake. The regional evapotranspiration increased by 12.8% between 2000 and 2014. Evapotranspiration increase is not homogeneous over the watershed but limited over the main agriculture regions. Agriculture activity is one of the major factors contributing to the regional desertification and recent disappearance of Poopó Lake.

  16. Effects of Environmental Factors on Nutrients Release at Sediment-Water Interface and Assessment of Trophic Status for a Typical Shallow Lake, Northwest China

    Directory of Open Access Journals (Sweden)

    Dekun Hou


    Full Text Available Surface sediment and water samples were collected from Daihai Lake to study the biogeochemical characteristics of nitrogen and phosphorus, to estimate the loads of these nutrients, and to assess their effects on water quality. The contents and spatial distributions of total phosphorus (TP, total nitrogen (TN, and different nitrogen forms in sediments were analyzed. The results showed that concentrations of TN and TP in surface sediments ranged from 0.27 to 1.78 g/kg and from 558.31 to 891.29 mg/kg, respectively. Ratios of C : N ranged between 8.2 and 12.1, which indicated that nitrogen accumulated came mainly from terrestrial source. Ratios of N : P in all sampling sites were below 10, which indicated that N was the limiting nutrient for algal growth in this lake. Effects of environment factors on the release of nitrogen and phosphorus in lake sediments were also determined; high pH values could encourage the release of nitrogen and phosphorus. Modified Carlson’s trophic state index (TSIM and comprehensive trophic state index (TSIC were applied to ascertain the trophic classification of the studied lake, and the values of TSIM and TSIC ranged from 53.72 to 70.61 and from 47.73 to 53.67, respectively, which indicated that the Daihai Lake was in the stage of hypereutropher.

  17. Plankton diversity and water quality assessment of three freshwater lakes of Mandi (Himachal Pradesh, India) with special reference to planktonic indicators. (United States)

    Thakur, R K; Jindal, R; Singh, Uday Bhan; Ahluwalia, A S


    The present study deals with the limnobiotic status of three selected lakes of Himachal Pradesh using physicochemical and biological parameters (especially phytoplankton and zooplankton) over a period of 2 years. One hundred forty-eight species belonging to nine groups of phytoplankton and 79 species belonging to five groups of zooplankton were identified from the lakes. Trophic level and the pollution status of the lakes were assessed upon the basis of Shannon diversity index (H'), species richness index (S), and physicochemical parameters. Plankton population size was correlated with biotic and abiotic parameters (pH, alkalinity, temperature, dissolved oxygen, transparency, phosphate, chloride, and nitrate). The present investigation revealed that the distribution of plankton species depended upon the physicochemical parameters of the environment. Based on water quality standards given by the Central Pollution Control Board, the water quality was between "A-B" at Prashar wetland, "C-D" at Kuntbhyog Lake, and "D-E" at Rewalsar Lake. The results from the present study indicated that the potential of planktons as bioindicators of trophic status is very high.

  18. Psychiatric disorder onset and first treatment contact in the United States and Ontario. (United States)

    Olfson, M; Kessler, R C; Berglund, P A; Lin, E


    The authors describe the timing of the first treatment contact following new-onset DSM-III-R mood, anxiety, and addictive disorders in community samples from the United States and Ontario, Canada, before and after passage of the Ontario Health Insurance Plan. The authors drew data from the National Comorbidity Survey (NCS) (N=8,098) and the mental health supplement to the Ontario Health Survey (OHS) (N= 9,953). They assessed psychiatric disorders with a modified version of the Composite International Diagnostic Interview; they also assessed retrospectively age at disorder onset and first treatment contact. They used the Kaplan-Meier method to generate time-to-treatment curves and survival analysis to compare time-to-treatment intervals across the two surveys. The overall time-to-treatment curves revealed substantial differences between disorders that were consistent across the two surveys. In both surveys, panic disorder had the highest probability of first-year treatment (NCS, 65.6%; OHS supplement, 52.6%), while phobia (NCS, 12.0%; OHS supplement: 6.5%) and addictive disorders (NCS, 6.4%; OHS supplement, 4.2%) had the lowest in both surveys. Retrospective subgroup analysis suggests that before the passage of the Ontario public insurance plan, the likelihood of receiving treatment in the year of disorder onset was greater in Ontario than in the United States but that this relationship reversed following passage of the Ontario plan. During this period, the authors observed no significant between-country differences in the probability of prompt treatment of adults with 12 or fewer years of education. These results challenge the assumption that the universal health insurance plan in Ontario promotes greater access to mental health services than is available in the United States for vulnerable groups. Marked differences between disorders in the speed to first treatment suggest that in both countries, clinical factors play an important role in the timing of the initial

  19. Use of oxygen-18 and deuterium to assess the hydrology of groundwater-lake systems: Chapter 3: Advances in chemistry (United States)

    Krabbenhoft, David P.; Bowser, Carl J.; Kendall, Carol; Gat, Joel


    A thorough understanding of a lake's hydrology is essential for many lake studies. In some situations the interactions between groundwater systems and lakes are complex; in other cases the hydrology of a multilake system needs to be quantified. In such places, stable isotopes offer an alternative to the more traditional piezometer networks, which are costly to install and time-consuming to maintain. The stable-isotope mass-balance relations presented here can be used to estimate groundwater exchange rates for individual lakes and geographically clustered lakes. These relations also can be used to estimate other hydrological factors, such as average relative humidity. In places where the groundwater system is unstable (e.g., where flow reversals occur), natural solute tracers may provide a better alternative than stable isotopes for estimating rates of groundwater flow to and from lakes.

  20. Regional-scale GIS-models for assessment of hazards from glacier lake outbursts: evaluation and application in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    C. Huggel


    Full Text Available Debris flows triggered by glacier lake outbursts have repeatedly caused disasters in various high-mountain regions of the world. Accelerated change of glacial and periglacial environments due to atmospheric warming and increased anthropogenic development in most of these areas raise the need for an adequate hazard assessment and corresponding modelling. The purpose of this paper is to pro-vide a modelling approach which takes into account the current evolution of the glacial environment and satisfies a robust first-order assessment of hazards from glacier-lake outbursts. Two topography-based GIS-models simulating debris flows related to outbursts from glacier lakes are presented and applied for two lake outburst events in the southern Swiss Alps. The models are based on information about glacier lakes derived from remote sensing data, and on digital elevation models (DEM. Hydrological flow routing is used to simulate the debris flow resulting from the lake outburst. Thereby, a multiple- and a single-flow-direction approach are applied. Debris-flow propagation is given in probability-related values indicating the hazard potential of a certain location. The debris flow runout distance is calculated on the basis of empirical data on average slope trajectory. The results show that the multiple-flow-direction approach generally yields a more detailed propagation. The single-flow-direction approach, however, is more robust against DEM artifacts and, hence, more suited for process automation. The model is tested with three differently generated DEMs (including aero-photogrammetry- and satellite image-derived. Potential application of the respective DEMs is discussed with a special focus on satellite-derived DEMs for use in remote high-mountain areas.

  1. [Pollution characteristics and health risk assessment of organochlorine pesticides (OCPs) in the water of Lake Qiandao and its major input rivers]. (United States)

    Tang, Fang-Liang; Zhang, Ming; Xu, Jian-Fen; Ruan, Dong-De; Chen, Feng; Wu, Zhi-Xu; Cheng, Xin-Liang


    Organochlorine pesticides (OCPs) were quantitatively determined by GC in several surface water samples collected in July 2011 and November 2011 from Lake Qiandao (Xin'an River Reservoir) and its major input rivers. Then the component characteristics and source apportionment of HCHs and DDTs were confirmed, and the health risk assessment was evaluated. The results showed that 8 OCPs were found to be in trace amount, and p,p'-DDT, a-HCH and p,p'-DDE were the highest frequently detected OCPs. The concentrations of total OCPs in surface water of the studied Lake ranged from 1.9 to 7.6 ng-L-1 , which were at lower pollution level, and 1.2-212 ng.L-1 in the samples from its three major input rivers. The spatial distribution of OCPs in the water of lake was varying, and Xin'an River, the mainstream of the lake, was the main input source of OCPs. Also, different contamination patterns among sampling seasons were found, the concentrations of OCPs in surface water collected in wet period were higher than those in dry season, which display the characteristics of nonpoint source pollution. According to the ratio of feature components, the OCPs in surface water from the Lake Qiandao originated largely from long distance transmission or degradation of technical HCHs, while additional sources of DDTs existed in the region. In addition, human health risk assessment of ingestion through the drinking water and skin contact absorption was performed using EPA recommends methods, the carcinogenic and non-carcinogenic risks caused by OCPs were 0. 06 x 10(-7)-23. 2 x 10(-7) and 3.43 x 10(-5) -6.01 x 10(-3), respectively. According to the acceptable risk level, the carcinogenic and non-carcinogenic risks of the chemicals investigated can be considered negligible in water body of Lake Qiandao.

  2. A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid


    G. Kostoski; C. Albrecht; S. Trajanovski; T. Wilke


    Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact.

    Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a ...

  3. Edge detection applied to Cassini images reveals no measurable displacement of Ontario Lacus' margin between 2005 and 2010 (United States)

    Cornet, Thomas; Bourgeois, Olivier; Le Mouélic, Stéphane; Rodriguez, Sébastien; Sotin, Christophe; Barnes, Jason W.; Brown, Robert H.; Baines, Kevin H.; Buratti, Bonnie J.; Clark, Roger N.; Nicholson, Phillip D.


    Ontario Lacus is thus far the largest flat-floored topographic depression of Titan's southern hemisphere interpreted as a permanent or ephemeral lake. From 2005 to 2010, it was imaged several times and at various wavelengths by ISS, VIMS and RADAR instruments onboard Cassini's spacecraft. We analyze the position and uncertainty of Ontario Lacus' margin in all these images using an edge detection method based on image derivation. We find that, given the range of uncertainties in contour locations derived from images, no measurable displacement of Ontario Lacus' margin can be detected between 2005 and 2010 at the actual image spatial resolutions. The discrepancy between this result and previous ones is attributable to differences in (1) the basics behind the methods used, (2) the actual spatial resolutions and contrasts of the available images due to differential atmospheric scattering effects at different wavelengths, and (3) the geomorphological interpretation of contours derived from images acquired at different wavelengths. This lack of measurable displacement in the images suggests that the imaged contour corresponds either (1) to the border of a surface liquid body, provided that potential changes in its extent over five terrestrial years were not sufficiently large to be measured, or (2) to the stationary topographic border between Ontario Lacus' depression and the surrounding alluvial plain. Potential displacements of Ontario Lacus' margin between 2005 and 2010 are thus below the actual resolution of currently available images or have to be sought for within the extent of the topographic depression rather than along its borders.

  4. Estimating sediment quality thresholds to prevent restrictions on fish consumption: Application to polychlorinated biphenyls and dioxins-furans in the Canadian Great Lakes. (United States)

    Bhavsar, Satyendra P; Gewurtz, Sarah B; Helm, Paul A; Labencki, Tanya L; Marvin, Christopher H; Fletcher, Rachael; Hayton, Alan; Reiner, Eric J; Boyd, Duncan


    Sediment quality thresholds (SQTs) are used by a variety of agencies to assess the potential for adverse impact of sediment-associated contaminants on aquatic biota, typically benthic invertebrates. However, sedimentary contaminants can also result in elevated fish contaminant levels, triggering consumption advisories that are protective of humans. As such, SQTs that would result in fish concentrations below consumption advisory levels should also be considered. To illustrate how this can be addressed, we first calculate biota sediment accumulation factors (BSAFs) for polychlorinated biphenyls (total PCB) and polychlorinated dioxins-furans (PCDD/Fs) in the Canadian Great Lakes using measured lake sediment and fish tissue concentrations in 4 fish species, namely, lake trout, whitefish, rainbow trout, and channel catfish. Using these BSAFs and tissue residue values for fish consumption advisories employed by the Ontario Ministry of the Environment (OMOE, Canada), we derive fish consumption advisory-based SQTs (fca-SQTs) that are likely to result in fish tissue residues that are safe to eat without restriction. The PCDD/Fs fca-SQTs ranged from 6 to 128 pg toxic equivalents (TEQ)/g dry weight (dw) and were above the Canadian Council of the Ministers of the Environment (CCME) threshold effect level (TEL) of 0.85 pg TEQ/g dw. In contrast, the total PCB fca-SQTs ranged from 1 to 60 ng/g dw and were generally below the CCME's TEL of 34.1 ng/g and OMOE's lowest effect level (LEL) of 70 ng/g; however, they were consistent with the OMOE's no effect level (NEL) of 10 ng/g. The fca-SQTs derived using the BSAF as well as food chain multiplier (FCM) approach for a smaller scale system (Hamilton Harbour in Lake Ontario) corresponded well with average lakewide Lake Ontario fca-SQTs. This analysis provides approximate sediment concentrations necessary for reducing fish consumption advisories for each of the Canadian Great Lakes and emphasizes the impacts of historical

  5. Assessing Potential Algal Blooms in a Shallow Fluvial Lake by Combining Hydrodynamic Modelling and Remote-Sensed Images

    National Research Council Canada - National Science Library

    Monica Pinardi; Andrea Fenocchi; Claudia Giardino; Stefano Sibilla; Marco Bartoli; Mariano Bresciani


    .... Due to multiple interplaying factors, understanding the distribution of phytoplankton in fluvial lakes is a complex but fundamental issue, in the context of increasing eutrophication, climate change...

  6. Assessing feeding competition between lake whitefish Core-gonus clupeaformis and round whitefish Prosopium cyl-indraceum

    Directory of Open Access Journals (Sweden)

    Andrew MACPHERSON, John A. HOLMES, Andrew M. MUIR,David L. G. NOAKES


    Full Text Available We collected lake whitefish Coregonus clupeaformis and round whitefish Prosopium cylindraceum from the main basin of Lake Huron and Georgian Bay in the Laurentian Great Lakes of North America to investigate details of diet and feeding tactics of these species in different seasons. Lake whitefish supports important commercial fisheries in Lake Huron and both species make use of habitats near the Bruce Nuclear Power Development, on the eastern shore of Lake Huron. Most fish of both species showed generalist feeding behavior, but some lake whitefish appeared to show specialist prey selection. The invasive spiny water flea Bythotrephes longimanus was an important component of the diet of both species. There was considerable dietary overlap between the whitefish species, but the ecological implications of these dietary overlaps are mitigated by the fact that dominant prey species differed in most seasons. We conclude that the potential for ecologically significant interactions between lake whitefish and round whitefish resulting from competition for similar benthic food resources in the main basin of Lake Huron is probably low [Current Zoology 56 (1: 109–117 2010].

  7. Occurrence, distribution, and ecological risk assessment of DDTs and heavy metals in surface sediments from Lake Awassa--Ethiopian Rift Valley Lake. (United States)

    Yohannes, Yared Beyene; Ikenaka, Yoshinori; Saengtienchai, Aksorn; Watanabe, Kensuke P; Nakayama, Shouta M M; Ishizuka, Mayumi


    Dichlorodiphenyltrichloroethanes (DDTs) and heavy metals are ubiquitous contaminants with high bioaccumulation and persistence in the environment, which can have adverse effects on humans and animals. Although applications of DDTs have been banned in many countries, developing countries like Ethiopia are still using these for agricultural and medicinal purposes. In addition, heavy metals are naturally present in the aquatic environment and distributed globally. In this study, the occurrence, distribution, and ecological risk of DDTs and heavy metals in surface sediments from one of the Ethiopian rift valley lakes were studied. Twenty-five surface sediment samples from Lake Awassa, Ethiopia were collected and analyzed for DDTs and heavy metals. Results showed that concentrations of total DDTs ranged from 3.64 to 40.2 ng/g dry weight. High levels of DDTs were observed in the vicinity of inflow river side and coastal areas with agricultural activities. The heavy metals content were followed the order Zn>Ni>Pb>Cu>Cr>Co>As>Cd>Hg. Correlation analysis and principal components analysis demonstrated that heavy metals were originated from both natural and anthropogenic inputs. The levels of DDE and DDD in surface sediments exceeded the sediment quality guideline values, i