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Sample records for southern lake victoria

  1. Distribution of Nile perch Lates niloticus in southern Lake Victoria is ...

    Although Nile perch Lates niloticus is assumed to be sensitive to low oxygen concentrations, it was found in deep water in Lake Victoria, where oxygen depletion is common during the rainy season. Since factors determining Nile perch distribution are not well understood its spatial distribution in the Mwanza Gulf of Lake ...

  2. Dietary shifts in Brycinus sadleri (Pisces : Characidae) from southern Lake Victoria

    Wanink, J.H.; Joordens, J.C.A.

    2007-01-01

    We studied the diet of Brycinus sadleri in Lake Victoria after extensive environmental changes during the 1980s. To check for diet expansion following these changes, as observed in some other fish species, we compared our results with data from the 1950s. Stomach contents were analysed in relation

  3. Total mercury concentration in common fish species of Lake Victoria ...

    Total mercury (THg) concentration was analysed in muscles of common fish species of Lake Victoria in the eastern and southern parts of the lake using cold vapour Atomic Absorption Spectrophotometric technique. Mercury concentration in all fish species was generally lower than the WHO maximum allowable ...

  4. Pesticide residues in Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) from Southern Lake Victoria, Tanzania

    Henry, L.; Kishimba, M.A.

    2006-01-01

    Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) samples were collected from fish landing stations in nine riparian districts on the Tanzanian side of Lake Victoria and screened for residues of 64 organochlorine, organophosphorus, carbamate, and pyrethroid pesticides. The residue levels in the fish fillet were up to 0.003, 0.03 and 0.2 mg/kg fresh weight (0.7, 3.8 and 42 mg/kg lipid weight) of fenitrothion, DDT and endosulfan, respectively. Mean levels within sites were up to 0.002, 0.02 and 0.1 mg/kg fresh weight (0.5, 0.5 and 16 mg/kg lipid weight), respectively. The detection of higher levels of p,p'-DDT than the degradation products (p,p'-DDD and p,p'-DDE), and higher levels of endosulfan isomers (α and β) than the sulphate, in fish samples, implied recent exposure of fish to DDT and endosulfan, respectively. Generally, most of the fish samples had residue levels above the average method detection limits (MDLs), but were within the calculated ADI. - Fish from Lake Victoria had relatively low pesticide levels

  5. Pesticide residues in Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) from Southern Lake Victoria, Tanzania

    Henry, L. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania); Kishimba, M.A. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania)]. E-mail: kishimba@chem.udsm.ac.tz

    2006-03-15

    Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) samples were collected from fish landing stations in nine riparian districts on the Tanzanian side of Lake Victoria and screened for residues of 64 organochlorine, organophosphorus, carbamate, and pyrethroid pesticides. The residue levels in the fish fillet were up to 0.003, 0.03 and 0.2 mg/kg fresh weight (0.7, 3.8 and 42 mg/kg lipid weight) of fenitrothion, DDT and endosulfan, respectively. Mean levels within sites were up to 0.002, 0.02 and 0.1 mg/kg fresh weight (0.5, 0.5 and 16 mg/kg lipid weight), respectively. The detection of higher levels of p,p'-DDT than the degradation products (p,p'-DDD and p,p'-DDE), and higher levels of endosulfan isomers ({alpha} and {beta}) than the sulphate, in fish samples, implied recent exposure of fish to DDT and endosulfan, respectively. Generally, most of the fish samples had residue levels above the average method detection limits (MDLs), but were within the calculated ADI. - Fish from Lake Victoria had relatively low pesticide levels.

  6. Has climate change disrupted stratification patterns in Lake Victoria ...

    Has climate change disrupted stratification patterns in Lake Victoria, East Africa? ... Climate change may threaten the fisheries of Lake Victoria by increasing density differentials in the water column, thereby strengthening stratification and increasing the ... Keywords: deoxygenation, fisheries, global warming, thermocline

  7. The diversity of benthic mollusks of Lake Victoria and Lake Burigi ...

    Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only ...

  8. Causes and effects of the Lake Victoria ecological revolution

    Goudswaard, Pleun Cornelis

    2006-01-01

    Nile perch was introduced in Lake Victoria in the 1950s and exploded in number during the 1980s. The process of colonization of the lake by this predatory fish is described and explained. The changes in a number of other fauna elements of Lake Victoria are described and explained. Not only Nile

  9. Adaptive responses to environmental changes in Lake Victoria cichlids

    Rijssel, Jacobus Cornelis van (Jacco)

    2014-01-01

    Lake Victoria cichlids show the fastest vertebrate adaptive radiation known which is why they function as a model organism to study evolution. In the past 40 years, Lake Victoria experienced severe environmental changes including the boom of the introduced, predatory Nile perch and eutrophication.

  10. Lake Victoria's Water Budget and the Potential Effects of Climate ...

    This paper presents the Lake Victoria water budget for the period 1950-2004 and findings of a study on potential climate change impact on the lake's Hydrology through the 21st Century. The mass balance components are computed from measured and simulated data. A2 and B2 emission scenarios of the Special Report ...

  11. Early warnings of hazardous thunderstorms over Lake Victoria

    Thiery, Wim; Gudmundsson, Lukas; Bedka, Kristopher; Semazzi, Fredrick H. M.; Lhermitte, Stef; Willems, Patrick; van Lipzig, Nicole P. M.; Seneviratne, Sonia I.

    2017-07-01

    Weather extremes have harmful impacts on communities around Lake Victoria in East Africa. Every year, intense nighttime thunderstorms cause numerous boating accidents on the lake, resulting in thousands of deaths among fishermen. Operational storm warning systems are therefore crucial. Here we complement ongoing early warning efforts based on numerical weather prediction, by presenting a new satellite data-driven storm prediction system, the prototype Lake Victoria Intense storm Early Warning System (VIEWS). VIEWS derives predictability from the correlation between afternoon land storm activity and nighttime storm intensity on Lake Victoria, and relies on logistic regression techniques to forecast extreme thunderstorms from satellite observations. Evaluation of the statistical model reveals that predictive power is high and independent of the type of input dataset. We then optimise the configuration and show that false alarms also contain valuable information. Our results suggest that regression-based models that are motivated through process understanding have the potential to reduce the vulnerability of local fishing communities around Lake Victoria. The experimental prediction system is publicly available under the MIT licence at http://github.com/wthiery/VIEWS.

  12. Nutritional composition and shelflife of the lake victoria nile perch ...

    Nile perch, the most important commercial fish species from the Lake Victoria fishery, contributes about 67% of Kenya's total annual fish export earnings. Despite the Nile perch being an important foreign exchange earner, little information is available on its nutritional composition and shelf life on ice, information that is ...

  13. ('fingerponds\\') in the wetlands of Lake Victoria, Kenya

    The potential effect on ecosystem integrity of the use of natural wetlands for seasonal wetland fishponds ('fingerponds\\'), integrated with vegetable production for livelihood demands, was evaluated using experimental sites at Lake Victoria, Kenya. Soluble reactive phosphorous and total phosphorus, ammonium, nitrate and ...

  14. Transactional sex in the fishing communities along Lake Victoria ...

    The study describes the nature, context and implications of a unique form of transactional sexual relationships in the fishing communities along Lake Victoria in Kisumu County, Kenya. We conducted 12 focus group discussions and 17 key informant interviews among fishermen, fishmongers and fish transporters in Kisumu.

  15. Fishing Business Arrangements and Sustainability in Lake Victoria ...

    In this article an attempt is made to analyse the existing production relations between the owners of the vessels and the crewmembers and the concern for sustainability. Our results found that the existing sharing system in Lake Victoria poses a big challenge in as far as sustainability is concerned. Some of the system such ...

  16. Energy and Environment in the Lake Victoria basin.

    Arungu-Olende, S.

    2006-01-01

    The local and national economies of Lake Victoria basin communities are heavily dependent on energy that fuels agriculture, industry, commerce, transportation and other economic activities; and powers our houses, offices, hospitals and buildings. Energy is therefore key to facilitating the development income generating opportunities, improving living standards, reducing poverty, and ensuring the protection of the environment. The development and use of various forms of renewable and non-renew...

  17. A review of mercury in Lake Victoria, East Africa: implications for human and ecosystem health.

    Campbell, Linda; Dixon, D G; Hecky, R E

    2003-01-01

    Lake Victoria, East Africa, has been the site of many recent studies measuring mercury (Hg) concentrations in water, fish, sediment, soil, and humans. Most of these studies were motivated by concerns about Hg contamination from processing of gold ore on the southern shores. Total Hg (THg) concentrations in fish were usually below permissible World Health Organization (WHO) concentrations and international marketing limits and do not threaten the lucrative export industry. Nile perch 3-10 kg and most >10 kg had THg concentrations above the WHO threshold concentrations for at-risk groups (200 ng/g). Elevated THg concentrations in large Nile perch are not of major concern because Nile perch are rarely consumed by the people living on Lake Victoria and very large Nile perch are becoming increasingly rare in catches. Water THg concentrations were below Canadian drinking water guidelines but were elevated relative to those in the northern Great Lakes. Sediment and soil THg concentrations were within inter-national guidelines and are comparable to those in northern latitudes but are lower than those in the Amazon basin. Biomass burning and soil erosion are estimated to be the major sources of THg for the lake and probably constitute a larger source of THg than gold mining in Tanzania.THg concentrations in urine and hair from human volunteers indicate that while gold miners and frequent skin-bleaching cream users are at risk of inorganic mercury poisoning, the rest of the population, including fishermen, is not. Human exposure assessments demonstrated that fish consumption and soil geophagy constitute major sources of THg for humans, but the total estimated daily intake of THg was below the Health Canada tolerable daily intake (TDI) limits. The use of beauty creams containing high inorganic Hg concentrations, however, caused the estimated THg exposure to exceed the TDI. The high THg content in the hair of regular cream users supports this assessment. The nutritional

  18. Mitigation of environmental problems in Lake Victoria, East Africa: causal chain and policy options analyses.

    Odada, Eric O; Olago, Daniel O; Kulindwa, Kassim; Ntiba, Micheni; Wandiga, Shem

    2004-02-01

    Lake Victoria is an international waterbody that offers the riparian communities a large number of extremely important environmental services. Over the past three decades or so, the lake has come under increasing and considerable pressure from a variety of interlinked human activities such as overfishing, species introductions, industrial pollution, eutrophication, and sedimentation. In this paper we examine the root causes for overfishing and pollution in Lake Victoria and give possible policy options that can help remediate or mitigate the environmental degradation.

  19. Conserved Receptor-Binding Domains of Lake Victoria Marburgvirus and Zaire Ebolavirus Bind a Shared Receptor

    Kuhn, Jens H; Radoshitzky, Sheli R; Guth, Alexander C; Warfield, Kelly L; Li, Wenhui; Vincent, Martin J; Towner, Jonathan S; Nichol, Stuart T; Bavari, Sina; Choe, Hyeryun

    2006-01-01

    .... Both fragments specifically inhibited replication of infectious Zaire ebolavirus, as well as entry of retroviruses pseudotyped with either Lake Victoria marburgvirus or Zaire ebolavirus GP(sub 1,2...

  20. Chemodenitrification in the cryoecosystem of Lake Vida, Victoria Valley, Antarctica.

    Ostrom, N E; Gandhi, H; Trubl, G; Murray, A E

    2016-11-01

    Lake Vida, in the Victoria Valley of East Antarctica, is frozen, yet harbors liquid brine (~20% salt, >6 times seawater) intercalated in the ice below 16 m. The brine has been isolated from the surface for several thousand years. The brine conditions (permanently dark, -13.4 °C, lack of O 2 , and pH of 6.2) and geochemistry are highly unusual. For example, nitrous oxide (N 2 O) is present at a concentration among the highest reported for an aquatic environment. Only a minor 17 O anomaly was observed in N 2 O, indicating that this gas was predominantly formed in the lake. In contrast, the 17 O anomaly in nitrate (NO3-) in Lake Vida brine indicates that approximately half or more of the NO3- present is derived from atmospheric deposition. Lake Vida brine was incubated in the presence of 15 N-enriched substrates for 40 days. We did not detect microbial nitrification, dissimilatory reduction of NO3- to ammonium (NH4+), anaerobic ammonium oxidation, or denitrification of N 2 O under the conditions tested. In the presence of 15 N-enriched nitrite (NO2-), both N 2 and N 2 O exhibited substantial 15 N enrichments; however, isotopic enrichment declined with time, which is unexpected. Additions of 15 N-NO2- alone and in the presence of HgCl 2 and ZnCl 2 to aged brine at -13 °C resulted in linear increases in the δ 15 N of N 2 O with time. As HgCl 2 and ZnCl 2 are effective biocides, we interpret N 2 O production in the aged brine to be the result of chemodenitrification. With this understanding, we interpret our results from the field incubations as the result of chemodenitrification stimulated by the addition of 15 N-enriched NO2- and ZnCl 2 and determined rates of N 2 O and N 2 production of 4.11-41.18 and 0.55-1.75 nmol L -1  day -1 , respectively. If these rates are representative of natural production, the current concentration of N 2 O in Lake Vida could have been reached between 6 and 465 years. Thus, chemodenitrification alone is sufficient to explain the

  1. Isotopic character of Cambro-Ordovician plutonism, southern Victoria Land

    Cox, S.C.; Parkinson, D.L.; Allibone, A.H.; Cooper, A.F.

    2000-01-01

    Previous mapping of granitoid rocks in the Dry Valleys area of southern Victoria Land, Antarctica, identified the calc-alkaline (DV1a), adakitic (DV1b), and monzonitic (DV2) suites. A fourth older suite comprising alkaline gabbro, syenite, and A-type granite occurs in the Mt Dromedary area c. 80 km to the south. U-Pb zircon dating of Bonney Pluton, the largest calc-alkaline DV1a intrusion, indicates emplacement of this regional-scale body at 505 +/- 2 Ma. Pb-loss and inherited zircon were common to Bonney Pluton analyses of this study. U-Pb dating of monazite from Valhalla Pluton, a principal DV1b suite adakitic intrusion, indicates emplacement at 488 +/- 2 Ma. The Bonney Pluton age constrains the peak of calc-alkaline plutonism at 505 Ma and the Valhalla Pluton age records the major pulse of adakitic plutonism that is inferred to mark the final stages of subduction c. 490 Ma along this section of the East Antarctic margin. Nd and Sr isotope data for the calc-alkaline DV1a suite and adakitic DV1b suite define distinct ranges for each suite, supporting their subdivision on the basis of field relationships, petrography, and whole-rock geochemistry. Calc-alkaline DV1a suite granite magmas have eNd(T) = -4.2 to -6.1 and Sri = 0.7071-0.7079, whereas the adakitic DV1b suite rocks have a wider range of eNd(T) = -1.9 to -7.2 and Sri = 0.7065-0.7097. The isotopic data suggest a significant mantle component and subordinate crustal component in the source region of both suites. Time-dependent variations in the isotopic ratios of DV1a and DV1b suites imply a progressive increase in the proportion of more radiogenic material in the source region of the granitoid rocks, either mantle- or crust-derived material. Larger adakitic DV1b plutons are more 'evolved' than equivalent, smaller plutons of the same DV1b suite. Vanda Dikes and monzonitic DV2 suite intrusions are characterised by particularly low Sri = 0.7044-0.7067 and near-constant eNd(T) = -4.8 to -5.3, which indicate a

  2. Regional nitrogen budget of the Lake Victoria Basin, East Africa: syntheses, uncertainties and perspectives

    Zhou, Minghua; Brandt, Patric; Pelster, David; Rufino, Mariana C.; Robinson, Timothy; Butterbach-Bahl, Klaus

    2014-10-01

    Using the net anthropogenic nitrogen input (NANI) approach we estimated the N budget for the Lake Victoria Basin in East Africa. The NANI of the basin ranged from 887 to 3008 kg N km-2 yr-1 (mean: 1827 kg N km-2 yr-1) for the period 1995-2000. The net nitrogen release at basin level is due primarily to livestock and human consumption of feed and foods, contributing between 69% and 85%. Atmospheric oxidized N deposition contributed approximately 14% to the NANI of the Lake Victoria Basin, while either synthetic N fertilizer imports or biological N fixations only contributed less than 6% to the regional NANI. Due to the low N imports of feed and food products (export to Lake Victoria accounted for 16%, which is much lower than for watersheds located in Europe and USA (25%). A significant reduction of the uncertainty of our N budget estimate for Lake Victoria Basin would be possible if better data on livestock systems and riverine N export were available. Our study indicates that at present soil N mining is the main source of nitrogen in the Lake Victoria Basin. Thus, sustainable N management requires increasing agricultural N inputs to guarantee food security and rehabilitation and protection of soils to minimize environmental costs. Moreover, to reduce N pollution of the lake, improving management of human and animal wastes needs to be carefully considered in future.

  3. Water hyacinth hotspots in the Ugandan waters of Lake Victoria in ...

    Water hyacinth invaded Lake Victoria in the 1980s and, by 1998, had attained peak coverage of approximately 2 000 ha in the Ugandan waters of the lake. Control interventions, especially via biological means, significantly reduced the weed's coverage to non-nuisance levels (<10 ha) by 1999. Although resurgence was ...

  4. Levels of toxic metals in multisectoral samples from Winam Gulf of Lake Victoria.

    Ongeri, D M K; Lalah, J O; Wandiga, S O; Schramm, K W; Michalke, B

    2009-01-01

    In this study, the distribution and sources of inputs of trace metals including Cd, Cu, Zn and Pb from various sources as well as Fe which is widely used in the construction industry, into Winam Gulf of Lake Victoria were investigated. The sampling sites were located up streams and down streams of four rivers (Sio, Nyamasaria, Nyando and Sondu-Miriu), in four beaches along the lake (Port Victoria, Kisumu Car Wash, Dunga and Hippo point beaches) and in three estates (Nyamasaria, Migosi and Nyawita) in Kisumu city, covering potential agrochemical and industrial sources and drinking water points, respectively. The concentrations (in microg/L) of trace metals analysed in the lake and river waters ranged from Car Wash area. The study confirmed that the concentrations of the metals accumulate downstream in the rivers both in water and sediment and these rivers are major sources of the heavy metal load into Winam Gulf of Lake Victoria.

  5. Malaria vectors in Lake Victoria and adjacent habitats in western Kenya.

    Noboru Minakawa

    Full Text Available The prevalence of malaria among the residents of the Lake Victoria basin remains high. The environment associated with the lake may maintain a high number of malaria vectors. Lake habitats including water hyacinths have been suspected to be the source of vectors. This study investigated whether malaria vectors breed in the lake habitats and adjacent backwater pools. Anopheline larvae were collected within the littoral zone of the lake and adjacent pools located along approximately 24.3 km of the lakeshore in western Kenya, and their breeding sites characterized. Three primary vector species, Anopheles arabiensis, Anopheles gambiae s.s. and Anopheles funestus s.s., and three potential vectors, were found in the lake habitats. Unexpectedly, An. arabiensis was the most dominant vector species in the lake sampling sites. Its habitats were uncovered or covered with short grass. A potential secondary malaria vector, Anopheles rivulorum, dominated the water hyacinths in the lake. Most breeding sites in the lake were limited to areas that were surrounded by tall emergent plants, including trees, and those not exposed to waves. Nearly half of adjacent habitats were lagoons that were separated from the lake by sand bars. Lagoons contained a variety of microhabitats. Anopheles arabiensis dominated open habitats, whereas An. funestus s.s. was found mainly in vegetated habitats in lagoons. The current study confirmed that several breeding sites are associated with Lake Victoria. Given that Lake Victoria is the second largest lake in the world, the lake related habitats must be extensive; therefore, making targeted vector control difficult. Further exploration is necessary to estimate the effects of lake associated habitats on malaria transmission so as to inform a rational decision-making process for vector control.

  6. Satellite-Based Assessment of the spatial extent of Aquatic Vegetation in Lake Victoria

    Clark, W.; Aligeti, N.; Jeyaprakash, T.; Martins, M.; Stodghill, J.; Winstanley, H.

    2011-12-01

    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.

  7. Diel vertical migration of major fish-species in Lake Victoria, East Africa

    Goudswaard, P.C.; Wanink, J.H.; Witte, F.; Katunzi, E.F.B.; Berger, M.R.; Postma, D.J.

    2004-01-01

    Understanding of migration patterns is essential in the interpretation of hydro-acoustic stock assessment data of partly demersal partly pelagic fish stocks. In this paper we provide this kind of information for some species that were common in the Mwanza Gulf of Lake Victoria in the 1980s, before

  8. Diel vertical migration of major fish-species in Lake Victoria, East Africa.

    Goudswaard, KPC; Wanink, JH; Witte, F; Katunzi, EFB; Berger, MR; Postma, DJ

    2004-01-01

    Understanding of migration patterns is essential in the interpretation of hydro-acoustic stock assessment data of partly demersal partly pelagic fish stocks. In this paper we provide this kind of information for some species that were common in the Mwanza Gulf of Lake Victoria in the 1980s, before

  9. Nile perch fish processing waste along Lake Victoria in East Africa ...

    In East Africa, Nile perch fish processing into chilled fish fillet for export along Lake Victoria generate large proportions of both solid and liquid wastes. However, no thorough auditing and characterization of the waste has been done that would guide potential value addition through bioconversions and waste management.

  10. Existence versus extinction : Human-hippo conflicts in Lake Victoria Area, Kenya

    Post, A.W.C.H.M.

    2017-01-01

    This PhD dissertation examines the role of different organisations and affected communities in human-wildlife governance, with a focus on human-hippo conflicts in Lake Victoria Area, Kenya. The hippo population in this area is under pressure due to human activities that impact on the wetland

  11. Nile perch fish processing waste along Lake Victoria in East Africa ...

    Nile perch fish processing waste along Lake Victoria in East Africa: Auditing and characterization. ... African Journal of Environmental Science and Technology ... If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs.

  12. Collapse and reorganization of a food web of Mwanza Gulf, Lake Victoria

    Downing, A.S.; Van Nes, E.H.; Janse, J.H.; Witte, F.; Cornelissen, I.J.M.; Scheffer, M.; Mooij, W.M.

    2012-01-01

    Lake Victoria (in East Africa) is the world's second largest fresh-water system. Over the past century the ecosystem has undergone drastic changes. Some 30 years after the introduction of Nile perch and tilapia in the 1950s, the highly diverse community of native haplochromines collapsed, leaving a

  13. Lake Victoria wetlands and the ecology of the Nile tilapia, Oreochromis niloticus Linne

    Balirwa, J.S.

    1998-01-01

    An ecological study of wetlands was undertaken in northern Lake Victoria (East Africa) between 1993 and 1996 with a major aim of characterising shallow vegetation-dominated interface habitats, and evaluating their importance for fish, in particular, for the stocked and socio-economically

  14. Eutrophication, Nile perch and food-web interactions in south-east Lake Victoria

    Cornelissen, I.J.M.

    2015-01-01

    The increasing eutrophication, the introduction of Nile perch (Lates niloticus) and the increasing fishing pressure has changed Lake Victoria tremendously the last century. Since the 1960s, eutrophication increased primary production, enabling an increase in fish production. However,

  15. Parameterization of the inherent optical properties of Murchison Bay, Lake Victoria

    Okullo, Willy; Ssenyonga, Taddeo; Hamre, Børge; Frette, Øyvind; Sørensen, K.; Stamnes, Jakob J.; Steigen, Andreas; Stamnes, Knut

    2007-12-01

    Lake Victoria, Africa's largest freshwater lake, suffers greatly from negative changes in biomass of species of fish and also from severe eutrophication. The continuing deterioration of Lake Victoria's ecological functions has great long-term consequences for the ecosystem benefits it provides to the countries bordering its shores. However, knowledge about temporal and spatial variations of optical properties and how they relate to lake constituents is important for a number of reasons such as remote sensing, modeling of underwater light fields, and long-term monitoring of lake waters. Based on statistical analysis of data from optical measurements taken during half a year of weekly cruises in Murchison Bay, Lake Victoria, we present a three-component model for the absorption and a two-component model for the scattering of light in the UV and the visible regions of the solar spectrum along with tests of their ranges of validity. The three-component input to the model for absorption is the chlorophyll-a (Chl-a), total suspended materials concentrations, and yellow substance absorption, while the two-component input to the model for scattering is the Chl-a concentration and total suspended materials.

  16. Species-specific relationships between water transparency and male coloration within and between two closely related Lake Victoria cichlid species

    Castillo Cajas, Ruth F; Selz, Oliver M; Ripmeester, Erwin A P; Seehausen, Ole; Maan, Martine E

    2012-01-01

    Environmental variation in signalling conditions affects animal communication traits, with possible consequences for sexual selection and reproductive isolation. Using spectrophotometry, we studied how male coloration within and between populations of two closely related Lake Victoria cichlid

  17. A Bottom-Up Understanding of Illegal, Unreported, and Unregulated Fishing in Lake Victoria

    Joseph Luomba

    2016-10-01

    Full Text Available Illegal, unreported, and unregulated (IUU fishing is a major concern in fisheries management around the world. Several measures have been taken to address the problem. In Lake Victoria, the alleviation of IUU fishing is implemented through the Regional Plan of Action (RPOA-IUU, which restricts use of certain fishing gear, as well as prohibits fishing in closed areas and during closed seasons. Despite the long-term efforts to monitor and control what goes on in the fisheries, IUU fishing has persisted in Lake Victoria. Inspired by interactive governance theory, this paper argues that the persistence of IUU fishing could be due to different images that stakeholders have about the situation, rather than the lack of management competency. Through structured interviews with 150 fisheries stakeholders on Ijinga Island in the southeastern part of Lake Victoria, Tanzania, using paired comparison questionnaires, the study elicits stakeholders’ perspective about the severity of different locally-pertinent fishing-related activities. The results show that while fisheries stakeholder groups agree on their judgments about certain fishing gears, some differences are also apparent. For instance, fisheries managers and scientists do not always agree with fishing people about what activities cause the most damage to fisheries resources and ecosystem. Further, they tend to consider some IUU fishing-related activities less damaging than some non-IUU fishing. Such disparity creates governability challenges, pointing to the need to revisit relevant regulatory measures and to make them consistent with the knowledge and judgments of all stakeholders. Based on these findings, we discuss governing interventions that may contribute to addressing IUU fishing in Lake Victoria and elsewhere.

  18. B chromosomes have a functional effect on female sex determination in Lake Victoria cichlid fishes.

    Kohta Yoshida

    2011-08-01

    Full Text Available The endemic cichlid fishes in Lake Victoria are a model system for speciation through adaptive radiation. Although the evolution of the sex-determination system may also play a role in speciation, little is known about the sex-determination system of Lake Victoria cichlids. To understand the evolution of the sex-determination system in these fish, we performed cytogenetic analysis in 11 cichlid species from Lake Victoria. B chromosomes, which are present in addition to standard chromosomes, were found at a high prevalence rate (85% in these cichlids. In one species, B chromosomes were female-specific. Cross-breeding using females with and without the B chromosomes demonstrated that the presence of the B chromosomes leads to a female-biased sex ratio in this species. Although B chromosomes were believed to be selfish genetic elements with little effect on phenotype and to lack protein-coding genes, the present study provides evidence that B chromosomes have a functional effect on female sex determination. FISH analysis using a BAC clone containing B chromosome DNA suggested that the B chromosomes are derived from sex chromosomes. Determination of the nucleotide sequences of this clone (104.5 kb revealed the presence of several protein-coding genes in the B chromosome, suggesting that B chromosomes have the potential to contain functional genes. Because some sex chromosomes in amphibians and arthropods are thought to be derived from B chromosomes, the B chromosomes in Lake Victoria cichlids may represent an evolutionary transition toward the generation of sex chromosomes.

  19. Reconstruction of Late Pleistocene Paleoenvironments using bulk geochemistry of paleosols from the Lake Victoria Region

    Beverly, Emily J.; Peppe, Daniel J.; Driese, Steven G.; Blegen, Nick; Faith, J. Tyler; Tryon, Christian A.; Stinchcomb, Gary E.

    2017-11-01

    The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at 17 ka and again at 15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94 to 36 ka) are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs), fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ) of the past (paleo-CZs). The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study). New paleosol-based mean annual precipitation (MAP) proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750108 mm yr-1 (CALMAG), 800182 mm yr-1 (CIA-K), and 1010228 mm yr-1 (PPM1.0) with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a 55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 ka and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans) and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and paleontological evidence suggests a

  20. Reconstruction of Late Pleistocene Paleoenvironments Using Bulk Geochemistry of Paleosols from the Lake Victoria Region

    Emily J. Beverly

    2017-11-01

    Full Text Available The impact of changing environments on the evolution and dispersal of Homo sapiens is highly debated, but few data are available from equatorial Africa. Lake Victoria is the largest freshwater lake in the tropics and is currently a biogeographic barrier between the eastern and western branches of the East African Rift. The lake has previously desiccated at ~17 ka and again at ~15 ka, but little is known from this region prior to the Last Glacial Maximum. The Pleistocene terrestrial deposits on the northeast coast of Lake Victoria (94–36 ka are ideal for paleoenvironmental reconstructions where volcaniclastic deposits (tuffs, fluvial deposits, tufa, and paleosols are exposed, which can be used to reconstruct Critical Zones (CZ of the past (paleo-CZs. The paleo-CZ is a holistic concept that reconstructs the entire landscape using geologic records of the atmosphere, hydrosphere, lithosphere, biosphere, and pedosphere (the focus of this study. New paleosol-based mean annual precipitation (MAP proxies from Karungu, Rusinga Island, and Mfangano Island indicate an average MAP of 750 ± 108 mm year−1 (CALMAG, 800 ± 182 mm year−1 (CIA-K, and 1,010 ± 228 mm year−1 (PPM1.0 with no statistical difference throughout the 11 m thick sequence. This corresponds to between 54 and 72% of modern precipitation. Tephras bracketing these paleosols have been correlated across seven sites, and sample a regional paleo-CZ across a ~55 km transect along the eastern shoreline of the modern lake. Given the sensitivity of Lake Victoria to precipitation, it is likely that the lake was significantly smaller than modern between 94 and 36 ka. This would have removed a major barrier for the movement of fauna (including early modern humans and provided a dispersal corridor across the equator and between the rifts. It is also consistent with the associated fossil faunal assemblage indicative of semi-arid grasslands. During the Late Pleistocene, the combined geologic and

  1. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS.

    Chrispine Nyamweya

    Full Text Available Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May and mixing (June-August. Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  2. Simulation of Lake Victoria Circulation Patterns Using the Regional Ocean Modeling System (ROMS).

    Nyamweya, Chrispine; Desjardins, Christopher; Sigurdsson, Sven; Tomasson, Tumi; Taabu-Munyaho, Anthony; Sitoki, Lewis; Stefansson, Gunnar

    2016-01-01

    Lake Victoria provides important ecosystem services including transport, water for domestic and industrial uses and fisheries to about 33 million inhabitants in three East African countries. The lake plays an important role in modulating regional climate. Its thermodynamics and hydrodynamics are also influenced by prevailing climatic and weather conditions on diel, seasonal and annual scales. However, information on water temperature and circulation in the lake is limited in space and time. We use a Regional Oceanographic Model System (ROMS) to simulate these processes from 1st January 2000 to 31st December 2014. The model is based on real bathymetry, river runoff and atmospheric forcing data using the bulk flux algorithm. Simulations show that the water column exhibits annual cycles of thermo-stratification (September-May) and mixing (June-August). Surface water currents take different patterns ranging from a lake-wide northward flow to gyres that vary in size and number. An under flow exists that leads to the formation of upwelling and downwelling regions. Current velocities are highest at the center of the lake and on the western inshore waters indicating enhanced water circulation in those areas. However, there is little exchange of water between the major gulfs (especially Nyanza) and the open lake, a factor that could be responsible for the different water quality reported in those regions. Findings of the present study enhance understanding of the physical processes (temperature and currents) that have an effect on diel, seasonal, and annual variations in stratification, vertical mixing, inshore-offshore exchanges and fluxes of nutrients that ultimately influence the biotic distribution and trophic structure. For instance information on areas/timing of upwelling and vertical mixing obtained from this study will help predict locations/seasons of high primary production and ultimately fisheries productivity in Lake Victoria.

  3. LAKE VICTORIA AND THE COMMON PROPERTY DEBATE: IS THE TRAGEDY OF THE COMMONS A THREAT TO ITS FUTURE?

    Erick Ochieng OGELLO

    2013-12-01

    Full Text Available Lake Victoria is the largest among the African Great Lakes in East African region that are believed to have both dynamic and fragile aquatic ecosystems. Within two decades, the lake has experienced extensive resource exploitation leading to constrained productivity and drastic decline of native biodiversity. Intensive non-selective fishing, catchment vegetation degradation, industrial and agricultural pollution, the introduction of exotic species and uneven patchwork of governmental laws are some of the reasons for the current ecological woes facing Lake Victoria. This paper intends to stimulate recognition of Lake Victoria and its catchment as a lived Com­mons, to be shared, protected, managed and enjoyed by all who live around it. The paper compares the original biodiversity status of the lake with the current status and discusses the role of unlimited access as a function of the loss of the Lake’s biological wealth. The Lake’s water resource base, fishery, wetlands and other aquatic resources have been exhaustively discussed. In this review, we uphold the Hardin’s school of thought that freedom of the commoners causes resource overuse leading to poverty. Therefore, limiting freedom could be essential. However, there is need for provision of alternative means of survival since people with no choices would continue over-exploiting ecosystems even under limited access. The Lake Victoria basin commons should be protected by strict legal and clear political frame­work based on public trust doctrine, reinforced in law that the Lake is vital for the survival of people, plants and animals living on or near it and therefore must be protected for the common good. The political jurisdictions should consider governing the Lake basin as one integrated watershed. It is our fervent hope that bordering communities will secure grass root movements to protect and nurture Lake Victoria and its environs for the benefit of the present and future

  4. Integrating remote sensing approach with pollution monitoring tools for aquatic ecosystem risk assessment and management: a case study of Lake Victoria (Uganda).

    Focardi, Silvia; Corsi, Ilaria; Mazzuoli, Stefania; Vignoli, Leonardo; Loiselle, Steven A; Focardi, Silvano

    2006-11-01

    Aquatic ecosystems around the world, lake, estuaries and coastal areas are increasingly impacted by anthropogenic pollutants through different sources such as agricultural, industrial and urban discharges, atmospheric deposition and terrestrial drainage. Lake Victoria is the second largest lake in the world and the largest tropical lake. Bordered by Tanzania, Uganda, and Kenya, it provides a livelihood for millions of Africans in the region. However, the lake is under threat from eutrophication, a huge decline in the number of native fish species caused by several factors including loss of biodiversity, over fishing and pollution has been recently documented. Increasing usage of pesticides and insecticides in the adjacent agricultural areas as well as mercury contamination from processing of gold ore on the southern shores are currently considered among the most emergent phenomena of chemical contamination in the lake. By the application of globally consistent and comprehensive geospatial data-sets based on remote sensing integrated with information on heavy metals accumulation and insecticides exposure in native and alien fish populations, the present study aims at assessing the environmental risk associated to the contamination of the Lake Victoria water body on fish health, land cover distribution, biodiversity and the agricultural area surrounding the lake. By the elaboration of Landsat 7 TM data of November 2002 and Landsat 7 TM 1986 we have calculated the agriculture area which borders the Lake Victoria bay, which is an upland plain. The resulting enhanced nutrient loading to the soil is subsequently transported to the lake by rain or as dry fall. The data has been inserted in a Geographical information System (ARCGIS) to be upgraded and consulted. Heavy metals in fish fillets showed concentrations rather low except for mercury being higher than others as already described in previous investigations. In the same tissue, cholinesterases activity (ChE) as an

  5. A pharyngeal jaw evolutionary innovation facilitated extinction in Lake Victoria cichlids.

    McGee, Matthew D; Borstein, Samuel R; Neches, Russell Y; Buescher, Heinz H; Seehausen, Ole; Wainwright, Peter C

    2015-11-27

    Evolutionary innovations, traits that give species access to previously unoccupied niches, may promote speciation and adaptive radiation. Here, we show that such innovations can also result in competitive inferiority and extinction. We present evidence that the modified pharyngeal jaws of cichlid fishes and several marine fish lineages, a classic example of evolutionary innovation, are not universally beneficial. A large-scale analysis of dietary evolution across marine fish lineages reveals that the innovation compromises access to energy-rich predator niches. We show that this competitive inferiority shaped the adaptive radiation of cichlids in Lake Tanganyika and played a pivotal and previously unrecognized role in the mass extinction of cichlid fishes in Lake Victoria after Nile perch invasion. Copyright © 2015, American Association for the Advancement of Science.

  6. Biological Diversity and Resilience: Lessons from the Recovery of Cichlid Species in Lake Victoria

    Alex O. Awiti

    2011-03-01

    Full Text Available A fundamental feature of the Anthropocene is the inexorable erosion of the self-repairing capacity or adaptive renewal of natural systems because of natural perturbation, exploitation, or management failure. The concept of resilience offers a systematic framework for understanding the dynamics and variables that govern response dynamics of ecosystems. Resilience of haplochromine cichlids is assessed using limnological and biodiversity changes in Lake Victoria, the world's second largest freshwater lake, over the last five decades. The review explores the resurgence of the haplochromine cichlids using Holling's adaptive renewal cycle and attempts to illustrate how resilience-based management approaches might learn from an inadvertent management experiment. The introduction in the 1980s of the Nile perch (Lates niloticus, a fecund and voracious predator of the endemic phytoplankton feeding haplochromine cichlids, anthropogenic eutrophication, and deep water hypoxia have combined in a synergistic way to increase the vulnerability of the lake ecosystem to perturbations that were hitherto absorbed. However, the upsurge in commercial Nile perch fishing appears to be enabling the resurgence of the haplochromine cichlids. The resurgence of haplochromine cichlids is characterized by phenotypic plasticity, ecological and life history traits and demonstrates the critical role of response diversity in the maintenance of systems resilience. Resilience of the haplochromine cichlids resides in the requisite functional response diversity and habitat diversity that provide the resources for renewal and regeneration. This paper concludes that management of Nile perch fisheries and control of nutrient loading into Lake Victoria could halt or reverse eutrophication, hence offer the best promise for a diverse, productive, and resilient social-ecological system.

  7. Reconstruction of a semi-arid late Pleistocene paleocatena from the Lake Victoria region, Kenya

    Beverly, Emily J.; Driese, Steven G.; Peppe, Daniel J.; Arellano, L. Nicole; Blegen, Nick; Faith, J. Tyler; Tryon, Christian A.

    2015-11-01

    The effect of changing environment on the evolution of Homo sapiens is heavily debated, but few data are available from equatorial Africa prior to the last glacial maximum. The Karungu deposits on the northeast coast of Lake Victoria are ideal for paleoenvironmental reconstructions and are best studied at the Kisaaka site near Karunga in Kenya (94 to > 33 ka) where paleosols, fluvial deposits, tufa, and volcaniclastic deposits (tuffs) are exposed over a 2 km transect. Three well-exposed and laterally continuous paleosols with intercalated tuffs allow for reconstruction of a succession of paleocatenas. The oldest paleosol is a smectitic paleo-Vertisol with saline and sodic properties. Higher in the section, the paleosols are tuffaceous paleo-Inceptisols with Alfisol-like soil characteristics (illuviated clay). Mean annual precipitation (MAP) proxies indicate little change through time, with an average of 764 ± 108 mm yr- 1 for Vertisols (CALMAG) and 813 ± 182 to 963 ± 182 mm yr- 1 for all paleosols (CIA-K). Field observations and MAP proxies suggest that Karungu was significantly drier than today, consistent with the associated faunal assemblage, and likely resulted in a significantly smaller Lake Victoria during the late Pleistocene. Rainfall reduction and associated grassland expansion may have facilitated human and faunal dispersals across equatorial East Africa.

  8. Two new species of zooplanktivorous haplochromine cichlids from Lake Victoria, Tanzania

    Marnix de Zeeuw

    2013-01-01

    Full Text Available Two new species of zooplanktivorous haplochromine cichlids from Lake Victoria, Tanzania, are described and illustrated. These species closely resemble each other. Their affinities to other zooplanktivorous haplochromines from Lake Victoria are discussed. Haplochromis argens sp. n., which featured under nicknames (mainly H. “argens” in more than 50 papers, was caught both in the Mwanza Gulf and the Emin Pasha Gulf, whereas H. goldschmidti sp. n. was only found in the Emin Pasha Gulf. Of the latter species only males are available, but it seems unlikely that it represents a case of male colour polymorphism as several presumably unrelated characters differ in sympatry between the two species, suggesting that there is no gene flow. Statistical analysis revealed that the overall difference between the two species is greater than that between the populations from the two locations. Body depth of the two species in sympatry in the Emin Pasha Gulf was more similar than that of H. goldschmidti sp. n. and the allopatric population of H. argens sp. n. from the Mwanza Gulf, which may indicate an overall environmental effect. However, several measurements related to the width of snout and mouth differed more between the populations of the two species in sympatry than between the allopatric populations. In contrast to a group of zooplanktivorous species that recovered successfully after environmental changes in the lake, H. argens sp. n. is among a group that became extremely rare and probably is in danger of extinction; the conservation status of H. goldschmidti sp. n. is currently unknown.

  9. Molecular records of climate variability and vegetation response since the Late Pleistocene in the Lake Victoria basin, East Africa

    Berke, M.A.; Johnson, T.C.; Werne, J.P.; Grice, K.; Schouten, S.; Sinninghe Damsté, J.S.

    2012-01-01

    New molecular proxies of temperature and hydrology are helping to constrain tropical climate change and elucidate possible forcing mechanisms during the Holocene. Here, we examine a similar to 14,000 year record of climate variability from Lake Victoria, East Africa, the world's second largest

  10. The Fontaine Pluton : an early Ross Orogeny calc-alkaline gabbro from southern Victoria Land, Antarctica

    Cottle, J.M.; Cooper, A.F.

    2006-01-01

    The Fontaine Pluton is a previously undescribed mafic intrusion outcropping at Fontaine Bluff on the south side of the Carlyon Glacier in southern Victoria Land, Antarctica. It is the southern-most member of a laterally extensive mafic suite emplaced at mid-crustal depths during the initial stages of the Ross Orogeny. The pluton comprises recrystallised hornblende-biotite gabbro, which in places shows well-defined centimetre to metre scale primary igneous layering. Recrystallised ultramafic enclaves composed of amphibole-chlorite-talc are inferred to be remnants of a chemically and mineralogically distinct cumulate fraction. The intrusion has a 87 Sr/ 86 Sr (i) ratio of 0.70679 and a 143 Nd/ 144 Nd (i) ratio of 0.51187 (εNd (i) = -1.2). This, coupled with other geochemical data, implies that the Fontaine Pluton was formed by c. 15% partial melting of a depleted mantle source that was subsequently contaminated by continental crust. Preliminary U-Pb geochronology on zircon suggests an emplacement age for the pluton of 546 ± 10 Ma. These new data indicate that Ross Orogeny magmatism in this area of southern Victoria Land was initiated in the late Neoproterozoic along a subducting plate margin. (author). 55 refs., 10 figs., 3 tabs

  11. Modelling nitrogen transformation and removal in mara river basin wetlands upstream of lake Victoria

    Mayo, Aloyce W.; Muraza, Marwa; Norbert, Joel

    2018-06-01

    Lake Victoria, the largest lake in Africa, is a resource of social-economic potential in East Africa. This lake receives water from numerous tributaries including Mara River, which contributes about 4.8% of the total Lake water inflow. Unfortunately, Mara River basin faces environmental problems because of intensive settlement, agriculture, overgrazing in the basin and mining activities, which has lead to water pollution in the river, soil erosion and degradation, decreased soil fertility, loss of vegetation cover, decreased water infiltration capacity and increased sedimentation. One of the pollutants carried by the river includes nitrogen, which has contributed to ecological degradation of the Lake Victoria. Therefore this research work was intended to determine the effectiveness of Mara River wetland for removal of nitrogen and to establish nitrogen removal mechanisms in the wetland. To predict nitrogen removal in the wetland, the dynamics of nitrogen transformation was studied using a conceptual numerical model that takes into account of various processes in the system using STELLA II version 9.0®2006 software. Samples of model input from water, plants and sediments were taken for 45 days and were analyzed for pH, temperature, and DO in situ and chemical parameters such as NH3-N, Org-N, NO2-N, and NO3-N were analyzed in the laboratory in accordance with Standard methods. For plants, the density, dominance, biomass productivity and TN were determined and for sediments TN was analyzed. Inflow into the wetland was determined using stage-discharge relationship and was found to be 734,400 m3/day and the average wetland volume was 1,113,500 m3. Data collected by this study were used for model calibration of nitrogen transformation in this wetland while data from another wetland were used for model validation. It was found that about 37.8% of total nitrogen was removed by the wetland system largely through sedimentation (26.6%), plant uptake (6.6%) and

  12. Intestinal schistosomiasis among preschool children along the shores of Lake Victoria in Uganda

    Nalugwa, A.; Olsen, Annette; Tukahebwa, M. E.

    2015-01-01

    Schistosomiasis, a disease caused by Schistosoma trematode parasites, affects hundreds of millions of people and accounts for more than 40% of the global health burden due to neglected tropical diseases. In Uganda, intestinal schistosomiasis is endemic in 73 out of 112 districts and about 55......% of the population of 36 million individuals are at risk. There is scanty information on the status and burden of schistosomiasis in preschool children less than six years of age in Uganda. This study aimed to assess the status of Schistosoma mansoni infections in children aged 1-5 years in Uganda. S. mansoni...... prevalence and intensity of infection were examined in 3058 children from 5 districts along Lake Victoria shoreline, eastern Uganda. For each child one stool sample was collected on three consecutive days. The Kato-Katz technique was used to prepare stool smears on slides for microscopic examination. Short...

  13. Gastropod diversity, distribution and abundance in habitats with and without anthropogenic disturbances in Lake Victoria, Kenya

    Lange, C. N.; Kristensen, Thomas K.; Madsen, Henry

    2013-01-01

    We investigated freshwater gastropod diversity, abundance and distribution in habitats with and without anthropogenic disturbance in two localities, Ndere in the Winam Gulf and Mbita Point, Lake Victoria, Kenya, from May 2002 to January 2004. A total of 133 984 gastropod specimens belonging to 15...... species were recorded, 14 from Mbita and 12 from Ndere. Two species, Ferrissia kavirondica and Cleopatra cridlandi, which were recorded only from undisturbed habitats, could be indicators of least disturbed habitats. Water chemistry did differ between fish landing sites and undisturbed habitats at some......, while other species may not tolerate these changes. In order to protect gastropod diversity and avoid dominance of intermediate hosts, such as B. choanomphala, a management plan for the use of these fish landing sites should be developed. This could include rules on how to dispose of fish remnants...

  14. Microbial quality and safety of fresh and dried Rastrineobola argentea from Lake Victoria, Tanzania

    Baniga, Zebedayo; Dalsgaard, Anders; Mhongole, Ofred J

    2017-01-01

    the bacteriological quality of fresh and dried sardines from Lake Victoria. Sardine samples were randomly collected from main landing sites and retail markets in the city of Mwanza. Total viable counts (TVC) in fresh sardines were in the range of 5.18–7.90 log10 cfu/g while those dried on racks contained 3.......13–4.85 log10 cfu/g which were 0.75% of those dried on sand with 4.80–7.13 log10 cfu/g (p .../g and those dried on sand contained 1.18–3.32 log10 mpn/g, however, sardines dried on racks, did not contain any E. coli. Similar findings were found in the two types of dried sardines from the retail markets. Prevalence of Salmonella spp. in fresh R. argentea was 25% (n = 40), sand dried sardines at landing...

  15. Impacts of population growth and economic development on water quality of a lake: case study of Lake Victoria Kenya water.

    Juma, Dauglas Wafula; Wang, Hongtao; Li, Fengting

    2014-04-01

    Anthropogenic-induced water quality pollution is a major environmental problem in freshwater ecosystems today. As a result of this, eutrophication of lakes occurs. Population and economic development are key drivers of water resource pollution. To evaluate how growth in the riparian population and in the gross domestic product (GDP) with unplanned development affects the water quality of the lake, this paper evaluates Lake Victoria Kenyan waters basin. Waters quality data between 1990 and 2012 were analyzed along with reviews of published literature, papers, and reports. The nitrate-nitrogen (NO3-N), soluble phosphorus (PO4-P), chlorophyll a, and Secchi transparencies were evaluated as they are key water quality indicators. The NO3-N increased from 10 μg l(-1) in 1990 to 98 μg 1(-1) in 2008, while PO4-P increased from 4 μg l(-1) in 1990 to 57 μg l(-1) in 2008. The population and economic growth of Kenya are increasing with both having minimums in 1990 of 24.143 million people and 12.18 billion US dollars, to maximums in 2010 of 39.742 million people and 32.163 billion US dollars, respectively. A Secchi transparency is reducing with time, indicating an increasing pollution. This was confirmed by an increase in aquatic vegetation using an analysis of moderate resolution imaging spectroradiometer (MODIS) images of 2000 and 2012 of Kenyan waters. This study found that increasing population and GDP increases pollution discharge thus polluting lakes. One of major factors causing lake water pollution is the unplanned or poor waste management policy and service.

  16. Perceptions about interventions to control schistosomiasis among the Lake Victoria island communities of Koome, Uganda.

    Richard E Sanya

    2017-10-01

    Full Text Available Praziquantel-based mass treatment is the main approach to controlling schistosomiasis mansoni in endemic areas. Interventions such as provision and use of safe water, minimising contact with infested water, disposal of stool in latrines and snail control provide key avenues to break the transmission cycle and can sustain the benefits of mass treatment in the long term. Efforts are also being made to develop a schistosomiasis vaccine which, if effective, might reduce the incidence of re-infection after treatment. However, any interventions deployed need to be acceptable to, and sustainable by, the target communities.In this qualitative study, we investigated the perceptions of six Lake Victoria island communities of Koome, Uganda, about interventions to control Schistosoma mansoni infection and their willingness to participate in Schistosoma vaccine trials. Thirty-two in-depth interviews, 12 key informant interviews and 10 focus group discussions were conducted. Data were analysed using a thematic content approach.Intestinal schistosomiasis was not regarded as a serious health problem because a mass treatment programme is in place. However, the communities lack safe water sources and latrines. Mass treatment with praziquantel, safe water supplies and use of toilets were deemed the most acceptable interventions by the participants. The communities are willing to participate in Schistosoma vaccine trials.Knowledge of a community's perception about interventions to control schistosomiasis can be valuable to policy makers and programme implementers intending to set up interventions co-managed by the community members. In this study, the views of the Lake Victoria island communities of Koome are presented. This study also provides data to guide further work on alternative interventions such as Schistosoma vaccine trials in these communities.

  17. Perceptions about interventions to control schistosomiasis among the Lake Victoria island communities of Koome, Uganda.

    Sanya, Richard E; Tumwesige, Edward; Elliott, Alison M; Seeley, Janet

    2017-10-01

    Praziquantel-based mass treatment is the main approach to controlling schistosomiasis mansoni in endemic areas. Interventions such as provision and use of safe water, minimising contact with infested water, disposal of stool in latrines and snail control provide key avenues to break the transmission cycle and can sustain the benefits of mass treatment in the long term. Efforts are also being made to develop a schistosomiasis vaccine which, if effective, might reduce the incidence of re-infection after treatment. However, any interventions deployed need to be acceptable to, and sustainable by, the target communities. In this qualitative study, we investigated the perceptions of six Lake Victoria island communities of Koome, Uganda, about interventions to control Schistosoma mansoni infection and their willingness to participate in Schistosoma vaccine trials. Thirty-two in-depth interviews, 12 key informant interviews and 10 focus group discussions were conducted. Data were analysed using a thematic content approach. Intestinal schistosomiasis was not regarded as a serious health problem because a mass treatment programme is in place. However, the communities lack safe water sources and latrines. Mass treatment with praziquantel, safe water supplies and use of toilets were deemed the most acceptable interventions by the participants. The communities are willing to participate in Schistosoma vaccine trials. Knowledge of a community's perception about interventions to control schistosomiasis can be valuable to policy makers and programme implementers intending to set up interventions co-managed by the community members. In this study, the views of the Lake Victoria island communities of Koome are presented. This study also provides data to guide further work on alternative interventions such as Schistosoma vaccine trials in these communities.

  18. Tsetse fly (G. f. fuscipes distribution in the Lake Victoria basin of Uganda.

    Mugenyi Albert

    2015-04-01

    Full Text Available Tsetse flies transmit trypanosomes, the causative agent of human and animal African trypanosomiasis. The tsetse vector is extensively distributed across sub-Saharan Africa. Trypanosomiasis maintenance is determined by the interrelationship of three elements: vertebrate host, parasite and the vector responsible for transmission. Mapping the distribution and abundance of tsetse flies assists in predicting trypanosomiasis distributions and developing rational strategies for disease and vector control. Given scarce resources to carry out regular full scale field tsetse surveys to up-date existing tsetse maps, there is a need to devise inexpensive means for regularly obtaining dependable area-wide tsetse data to guide control activities. In this study we used spatial epidemiological modelling techniques (logistic regression involving 5000 field-based tsetse-data (G. f. fuscipes points over an area of 40,000 km2, with satellite-derived environmental surrogates composed of precipitation, temperature, land cover, normalised difference vegetation index (NDVI and elevation at the sub-national level. We used these extensive tsetse data to analyse the relationships between presence of tsetse (G. f. fuscipes and environmental variables. The strength of the results was enhanced through the application of a spatial autologistic regression model (SARM. Using the SARM we showed that the probability of tsetse presence increased with proportion of forest cover and riverine vegetation. The key outputs are a predictive tsetse distribution map for the Lake Victoria basin of Uganda and an improved understanding of the association between tsetse presence and environmental variables. The predicted spatial distribution of tsetse in the Lake Victoria basin of Uganda will provide significant new information to assist with the spatial targeting of tsetse and trypanosomiasis control.

  19. Late holocene trends of phytoplankton productivity and anoxia as inferred from diatom and geochemical proxies in Lake Victoria, Eastern Africa

    Andama, M.; Lejju, J. B.; Tolo, C. U.

    2013-11-01

    Lake Victoria ecosystem has undergone major ecological changes in the recent decades. Sedimentary diatom analysis and Fe / Mn determined by Energy Dispersive X-ray Fluorescence (EDXRF) have provided phytoplankton (diatom) productivity and the resultant anoxia (Fe / Mn) in Lake Victoria at Napoleon Gulf during the late Holocene (1778 cal yr BP (calibrated years before present) to 2008 AD) with radiocarbon dates determined using Accelerator Mass Spectrometry standard method. The results showed that increased total diatom counts in Napoleon Gulf during the late Holocene correspond with increased Fe / Mn ratio (anoxia) in some of the profiles and not in others and in most cases those that correspond correlate very well with increased eutrophication from nitrate input (Total Nitrogen, TN). Therefore slightly increased anoxia not related to increased diatom productivity was recorded in Lake Victoria at Napoleon Gulf from the period 1778 to 1135 cal yr BP. There was slightly increased diatom productivity at Napoleon Gulf from the period 857 to 758 cal yr BP but it did not increase anoxia in the lake. The period 415 cal yr BP to 2008 AD recorded increased anoxia at Napoleon Gulf related to high diatom productivity especially from 415 to 390 cal yr BP and 191 cal yr BP to 2008 AD.

  20. Community genetics reveal elevated levels of sympatric gene flow among morphologically similar but not among morphologically dissimilar species of Lake Victoria cichlid fish

    Konijnendijk, N.; Joyce, D.A.; Mrosso, H.D.J.; Egas, M.; Seehausen, O.

    2011-01-01

    We examined genetic structure among five species of Lake Victoria haplochromine cichlids in four island communities, using a full factorial sampling design that compared genetic differentiation between pairs of species and populations of varying morphological similarity and geographical proximity.

  1. The reproduction of lake trout in southern Lake Superior

    Eschmeyer, Paul H.

    1955-01-01

    The principal spawning grounds of lake trout (Salvelinus namaycush namaycush) in United States waters of southern Lake Superior are on rocky shoals at depths of less than 20 fathoms. Most spawning occurs in October and early November. Of the mature fish collected on or near the spawning grounds, 60 to 69 percent were males. Among mature fish the average length of females was greater than that of males; few males less than 24 inches or females less than 26 inches in total length were caught. Recoveries of lake trout tagged on the spawning grounds showed that some males remained in the immediate area for a period of several weeks during the spawning season. Marked fish showed a tendency to return during later years to spawning grounds on which they had been tagged, even though many of them ranged long distances between spawning seasons.

  2. The population structure of Glossina fuscipes fuscipes in the Lake Victoria basin in Uganda: implications for vector control

    Hyseni, Chaz; Kato, Agapitus B; Okedi, Loyce M; Masembe, Charles; Ouma, Johnson O; Aksoy, Serap; Caccone, Adalgisa

    2012-01-01

    Abstract Background Glossina fuscipes fuscipes is the primary vector of trypanosomiasis in humans and livestock in Uganda. The Lake Victoria basin has been targeted for tsetse eradication using a rolling carpet initiative, from west to east, with four operational blocks (3 in Uganda and 1 in Kenya), under a Pan-African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC). We screened tsetse flies from the three Ugandan PATTEC blocks for genetic diversity at 15 microsatellite loci from con...

  3. Hydroclimatology of Lake Victoria region using hydrologic model and satellite remote sensing data

    S. I. Khan

    2011-01-01

    Full Text Available Study of hydro-climatology at a range of temporal scales is important in understanding and ultimately mitigating the potential severe impacts of hydrological extreme events such as floods and droughts. Using daily in-situ data over the last two decades combined with the recently available multiple-years satellite remote sensing data, we analyzed and simulated, with a distributed hydrologic model, the hydro-climatology in Nzoia, one of the major contributing sub-basins of Lake Victoria in the East African highlands. The basin, with a semi arid climate, has no sustained base flow contribution to Lake Victoria. The short spell of high discharge showed that rain is the prime cause of floods in the basin. There is only a marginal increase in annual mean discharge over the last 21 years. The 2-, 5- and 10- year peak discharges, for the entire study period showed that more years since the mid 1990's have had high peak discharges despite having relatively less annual rain. The study also presents the hydrologic model calibration and validation results over the Nzoia basin. The spatiotemporal variability of the water cycle components were quantified using a hydrologic model, with in-situ and multi-satellite remote sensing datasets. The model is calibrated using daily observed discharge data for the period between 1985 and 1999, for which model performance is estimated with a Nash Sutcliffe Efficiency (NSCE of 0.87 and 0.23% bias. The model validation showed an error metrics with NSCE of 0.65 and 1.04% bias. Moreover, the hydrologic capability of satellite precipitation (TRMM-3B42 V6 is evaluated. In terms of reconstruction of the water cycle components the spatial distribution and time series of modeling results for precipitation and runoff showed considerable agreement with the monthly model runoff estimates and gauge observations. Runoff values responded to precipitation events that occurred across the catchment during the wet season from March to

  4. The Development of a Customization Framework for the WRF Model over the Lake Victoria Basin, Eastern Africa on Seasonal Timescales

    R. Argent

    2015-01-01

    Full Text Available Lake Victoria, Africa, supports millions of people. To produce reliable climate projections, it is desirable to successfully model the rainfall over the lake accurately. An initial step is taken here with customization of the Weather, Research, and Forecast (WRF model. Of particular interest is an asymmetrical rainfall pattern across the lake basin, due to a diurnal land-lake breeze. The main aim is to present a customization framework for use over the lake. This framework is developed by conducting several series of model runs to investigate aspects of the customization. The runs are analyzed using Tropical Rainfall Measuring Mission rainfall data and Climatic Research Unit temperature data. The study shows that the choice of parameters and lake surface temperature initialization can significantly alter the results. Also, the optimal physics combinations for the climatology may not necessarily be suitable for all circumstances, such as extreme years. The study concludes that WRF is unable to reproduce the pattern across the lake. The temperature of the lake is too cold and this prevents the diurnal land-lake breeze reversal. Overall, this study highlights the importance of customizing a model to the region of research and presents a framework through which this may be achieved.

  5. Application of Satellite Observations to Manage Natural Disasters in the Lake Victoria Basin

    Habib, Shahid; Policelli, F.; Irwin, D.; Korme, Tesfaye; Adler, Bob; Hong, Yang

    2010-01-01

    Lake Victoria, the second largest fresh water lake in the Eastern part of Africa is a vital natural resource for the economic well being and prosperity of over 30 million people located in riparian regions of Uganda, Kenya and Tanzania. It covers a large area of about 68,870 km2 and produces a GDP of about US $30 billion per year. The region is also very much prone to natural disasters such as severe floods during heavy precipitation periods in the Eastern part of Africa. In addition to floods, the precipitation also produces large infestations of mosquito larvae due to the standing water in many areas. This further causes multiple vector borne diseases such as Malaria, Rift Valley Fever and more. These problems are of serious concern and require active and aggressive surveillance and management to minimize the loss of human and animal lives and property damage. Satellite imagery and observations along with the in situ measurements provide a great tool to analyze and study this area and inform the policy makers to make calculated policy decisions which are more beneficial to the environment. Recently, NASA and USAID have joined forces with the Regional Center for Mapping of Resources for Development (RCMRD) located in Nairobi, Kenya to utilize multiple NASA sensors such as TRMM, SRTM and MODIS to develop flood potential maps for the Lake Victoria Basin. The idea is to generate a flood forecasts and "nowcasts" that can be sent to the disaster management organizations of Uganda, Kenya, and Tanzania. Post flood event satellite imagery is becoming a common tool to assess the areas inundated by flooding. However, this work is unique undertaking by utilizing land imaging and atmospheric satellites to build credible flood potential maps. At same time, we are also studying the potential occurrence and spread of Rift Valley Fever disease based on the short term climate records and precipitation data. These activities require multi-nation coordination and agreements and

  6. Characterization of V1R receptor (ora) genes in Lake Victoria cichlids.

    Ota, Tomoki; Nikaido, Masato; Suzuki, Hikoyu; Hagino-Yamagishi, Kimiko; Okada, Norihiro

    2012-05-15

    Although olfaction could play a crucial role in underwater habitats by allowing fish to sense a variety of nonvolatile chemical signals, the importance of olfaction in species-rich cichlids is still controversial. In particular, examining whether cichlids rely on olfaction for reproduction is of primary interest to understand the mechanisms of speciation. In the present study, we explored the V1R (also known as ora) genes, which are believed to encode reproductive pheromone receptors in fish, in the genomes of Lake Victoria cichlids. By screening a bacterial artificial chromosome library, we identified all six intact V1R genes (V1R1 to V1R6) that have been reported in other teleost fish. Furthermore, RT-PCR and in situ hybridization analyses showed that all of the V1R genes were expressed in the olfactory epithelium, indicating that these receptors are functional in cichlids. These observations indicate that cichlids use V1R-mediated olfaction in some ways for their social behaviors. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. DISSOLVED OXYGEN MODELLING USING ARTIFICIAL NEURAL NETWORK: A CASE OF RIVER NZOIA, LAKE VICTORIA BASIN, KENYA

    Edwin Kimutai Kanda

    2016-11-01

    Full Text Available River Nzoia in Kenya, due to its role in transporting industrial and municipal wastes in addition to agricultural runoff to Lake Victoria, is vulnerable to pollution. Dissolved oxygen is one of the most important indicators of water pollution. Artificial neural network (ANN has gained popularity in water quality forecasting. This study aimed at assessing the ability of ANN to predict dissolved oxygen using four input variables of temperature, turbidity, pH and electrical conductivity. Multilayer perceptron network architecture was used in this study. The data consisted of 113 monthly values for the input variables and output variable from 2009–2013 which were split into training and testing datasets. The results obtained during training and testing were satisfactory with R2 varying from 0.79 to 0.94 and RMSE values ranging from 0.34 to 0.64 mg/l which imply that ANN can be used as a monitoring tool in the prediction of dissolved oxygen for River Nzoia considering the non-correlational relationship of the input and output variables. The dissolved oxygen values follow seasonal trend with low values during dry periods.

  8. Scenario-based water resources planning for utilities in the Lake Victoria region

    Mehta, Vishal K.; Aslam, Omar; Dale, Larry; Miller, Norman; Purkey, David R.

    Urban areas in the Lake Victoria (LV) region are experiencing the highest growth rates in Africa. As efforts to meet increasing demand accelerate, integrated water resources management (IWRM) tools provide opportunities for utilities and other stakeholders to develop a planning framework comprehensive enough to include short term (e.g. landuse change), as well as longer term (e.g. climate change) scenarios. This paper presents IWRM models built using the Water Evaluation And Planning (WEAP) decision support system, for three towns in the LV region - Bukoba (Tanzania), Masaka (Uganda), and Kisii (Kenya). Each model was calibrated under current system performance based on site visits, utility reporting and interviews. Projected water supply, demand, revenues and costs were then evaluated against a combination of climate, demographic and infrastructure scenarios up to 2050. Our results show that water supply in all three towns is currently infrastructure limited; achieving existing design capacity could meet most projected demand until 2020s in Masaka beyond which new supply and conservation strategies would be needed. In Bukoba, reducing leakages would provide little performance improvement in the short-term, but doubling capacity would meet all demands until 2050. In Kisii, major infrastructure investment is urgently needed. In Masaka, streamflow simulations show that wetland sources could satisfy all demand until 2050, but at the cost of almost no water downstream of the intake. These models demonstrate the value of IWRM tools for developing water management plans that integrate hydroclimatology-driven supply to demand projections on a single platform.

  9. Mini-FLOTAC and Kato-Katz: helminth eggs watching on the shore of Lake Victoria.

    Barda, Beatrice; Zepherine, Henry; Rinaldi, Laura; Cringoli, Giuseppe; Burioni, Roberto; Clementi, Massimo; Albonico, Marco

    2013-07-31

    One of the challenges for monitoring helminth control programmes based on preventive chemotherapy is the lack of a copro-parasitological gold-standard method that combines good sensitivity with quantitative performance, low cost, and easy-to-learn technique.The aim of our study was to evaluate and compare, the WHO recommended quantitative diagnostic technique (Kato-Katz) and the Mini-FLOTAC. Mini-FLOTAC is an innovative method based on floatation of helminths eggs with two different solutions (FS2 and FS7) using a close system (Fill-FLOTAC) with 5% fixative. Kato-Katz was performed following WHO recommendation. The study was carried out in a rural part of Tanzania, close to Lake Victoria, where the laboratory facilities are fairly scarce, and the basic technique used in the local laboratory (direct smear) was taken as reference standard. 201 children were screened for intestinal helminths and 91% of them were found to be positive. The agreement among the three techniques was calculated with k Cohen coefficient and was fairly good (k = 0.4), although the Mini-FLOTAC results were more sensitive for hookworm (98%) with FS2, and for S.mansoni (90%) with FS7 followed by Kato-Katz (91% and 60% respectively) and direct smear (30% and 10% respectively). A good agreement was found between Mini-FLOTAC and Kato-Katz (k = 0.81) with FS7 (k = 0.76) for hookworm diagnosis and a fairly good one for S.mansoni diagnosis (k = 0.5). For both infections we had a poor agreement between the two quantitative techniques and the direct smear (kMcMaster) and in different settings where other soil-transmitted helminths are also endemic.

  10. Identifying Water Insecurity Hotspots in the Lake Victoria Basin of Eastern Africa

    Pricope, N. G.; Shukla, S.; Linard, C.; Gaughan, A.

    2014-12-01

    The Lake Victoria Basin (LVB), one of Africa's most populated transboundary watersheds and home to more than 30 million inhabitants, is increasingly challenged by both water quality problems and water quantity shortages against a backdrop of climate variability and change; and other environmental challenges. As a result of pollution, droughts, more erratic rainfall, heightened demand for water for both consumption and agricultural needs as well as differences in water allocation among the riverine countries of Uganda, Tanzania, Kenya, Rwanda and Burundi, many parts of this region are already experiencing water scarcity on a recurrent basis. Furthermore, given projected annual population growth rates of 2.5 to 3.5% for the next 20 years, water shortages are likely to be exacerbated in the future. Analyzing historical changes in the water resources of this region is hence important to identify "hot spots" that might be most sensitive to future changes in climate and demography. In this presentation, we report the findings of a comprehensive analysis performed to (i) examine changes in water resources of LVB in recent decades and (ii) identify overlap between regions of significant changes in water resources with land cover changes and high population centers that are also projected to grow the fastest over the coming decades. We first utilize several satellite, stations and model(s) based climatic and hydrologic datasets to assess changes in water resources in this region. We then use a quality-controlled Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product to identify areas of significant land cover changes. Simultaneously we use projections of gridded population density based on differential growth rates for rural and urban population to estimate fastest projected human population growth for 2030 and 2050 relative to 2010 data. Using the outcomes of these change analysis we identify water insecurity hotspots in the LVB.

  11. Fish as bioindicators in aquatic environmental pollution assessment: A case study in Lake Victoria wetlands, Uganda

    Naigaga, I.; Kaiser, H.; Muller, W. J.; Ojok, L.; Mbabazi, D.; Magezi, G.; Muhumuza, E.

    Growing human population and industrialization have led to the pollution of most aquatic ecosystems and consequent deterioration in environmental water quality. Indicator organisms are needed to improve assessment programmes on the ecological impacts of anthropogenic activities on the aquatic environment. Fish have been widely documented as useful indicators of environmental water quality because of their differential sensitivity to pollution. This study investigated the environmental water quality of selected wetland ecosystems using fish as biological indicators. Fish community structure in relation to water quality was assessed in five wetlands along the shoreline of Lake Victoria from August 2006 to June 2008. Four urban wetlands were variedly impacted by anthropogenic activities while one rural wetland was less impacted, and served as a reference site. Fish species diversity, abundance and richness were assessed, and canonical correspondence analysis (CCA) was used to evaluate the relationship between the fish communities and environmental variables. Results revealed that urban effluent impacted negatively on water quality and consequently the fish community structure. A total of 29 fish species were recorded throughout the study with the lowest number of 15 species recorded in the most impacted site. Shannon diversity and Margalef species richness indices were highest at the references site and lowest at the most impacted site. Wetland haplochromis species dominated the reference site, while oreochromis species dominated the most impacted site. The inshore locations registered higher species diversity and low species richness than the offshore locations. Low dissolved oxygen, pH, secchi depth and high electrical conductivity, total phosphorous, and total nitrogen were strongly associated with the effluent-impacted sites and greatly influenced the fish community structure. This study recommends the use of fish as valuable biological indicators in aquatic

  12. Linking land use changes to surface water quality variability in Lake Victoria: some insights from remote sensing

    Mugo, R. M.; Limaye, A. S.; Nyaga, J. W.; Farah, H.; Wahome, A.; Flores, A.

    2016-12-01

    The water quality of inland lakes is largely influenced by land use and land cover changes within the lake's catchment. In Africa, some of the major land use changes are driven by a number of factors, which include urbanization, intensification of agricultural practices, unsustainable farm management practices, deforestation, land fragmentation and degradation. Often, the impacts of these factors are observable on changes in the land cover, and eventually in the hydrological systems. When the natural vegetation cover is reduced or changed, the surface water flow patterns, water and nutrient retention capacities are also changed. This can lead to high nutrient inputs into lakes, leading to eutrophication, siltation and infestation of floating aquatic vegetation. To assess the relationship between land use and land cover changes in part of the Lake Victoria Basin, a series of land cover maps were derived from Landsat imagery. Changes in land cover were identified through change maps and statistics. Further, the surface water chlorophyll-a concentration and turbidity were derived from MODIS-Aqua data for Lake Victoria. Chlrophyll-a and turbidity are good proxy indicators of nutrient inputs and siltation respectively. The trends in chlorophyll-a and turbidity concentrations were analyzed and compared to the land cover changes over time. Certain land cover changes related to agriculture and urban development were clearly identifiable. While these changes might not be solely responsible for variability in chlrophyll-a and turbidity concentrations in the lake, they are potentially contributing factors to this problem. This work illustrates the importance of addressing watershed degradation while seeking to solve water quality related problems.

  13. The rise and fall of water hyacinth in Lake Victoria and the Kagera River basin, 1989-2001

    Albright, Thomas P.; Moorhouse, T.G.; McNabb, T.J.

    2004-01-01

    Water hyacinth (Eichhornia crassipes (Mart.) Solms) is an invasive aquatic macrophyte associated with major negative economic and ecological impacts to the Lake Victoria region since the plant's establishment in Uganda in the 1980s. Reliable estimates of water hyacinth distribution and extent are required to gauge the severity of the problem through time, relate water hyacinth abundance to environmental factors, identify areas requiring management action, and assess the efficacy of management actions. To provide such estimates and demonstrate the utility of remote sensing for this application, we processed and analyzed remotely sensed imagery to determine the distribution and extent of water hyacinth. Maps were produced and coverage was quantified using a hybrid unsupervised image classification approach with manual editing for each of the riparian countries of Kenya, Tanzania, and Uganda, as well as for numerous gulfs and bays. A similar procedure was carried out for selected lakes in the Rwanda-Tanzania borderlands lakes region in the Kagera River basin. Results confirm the severity of the water hyacinth infestation, especially in the northern parts of the lake. A maximum lake-wide extent of at least 17,374 ha was attained in 1998. Following this, a combination of factors, including conditions associated with the 1997 to 1998 El Nin??o and biocontrol with water hyacinth weevils, appear to have contributed to a major decline in water hyacinth in the most affected parts of the lake. Some lakes in the Kagera basin, such as Lake Mihindi, Rwanda, were severely infested in the late 1990s, but the level of infestation in most of these decreased markedly by the early 2000s.

  14. Balancing the people, profit and planet dimensions in international marketing channels : a study on coordinating mechanisms in the Nile perch channel from Lake Victoria

    Kambewa, E.

    2007-01-01

    Keywords: people, profit, planet, marketing channels, contracts, sustainability, quality,LakeVictoria, conjointanalysis

  15. A post-Calumet shoreline along southern Lake Michigan

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

    2007-01-01

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

  16. Changes in the dreissenid community in the lower Great Lakes with emphasis on southern Lake Ontario

    Mills, Edward L.; Chrisman, Jana R.; Baldwin, Brad; Owens, Randall W.; O'Gorman, Robert; Howell, Todd; Roseman, Edward F.; Raths, Melinda K.

    1999-01-01

    A field study was conducted in the lower Great Lakes to assess changes in spatial distribution and population structure of dreissenid mussel populations. More specifically, the westward range expansion of quagga mussel into western Lake Erie and toward Lake Huron was investigated and the shell size, density, and biomass of zebra and quagga mussel with depth in southern Lake Ontario in 1992 and 1995 were compared. In Lake Erie, quagga mussel dominated the dreissenid community in the eastern basin and zebra mussel dominated in the western basin. In southern Lake Ontario, an east to west gradient was observed with the quagga mussel dominant at western sites and zebra mussel dominant at eastern locations. Mean shell size of quagga mussel was generally larger than that of zebra mussel except in western Lake Erie and one site in eastern Lake Erie. Although mean shell size and our index of numbers and biomass of both dreissenid species increased sharply in southern Lake Ontario between 1992 and 1995, the increase in density and biomass was much greater for quagga mussels over the 3-year period. In 1995, zebra mussels were most abundant at 15 to 25 m whereas the highest numbers and biomass of quagga mussel were at 35 to 45 m. The quagga mussel is now the most abundant dreissenid in areas of southern Lake Ontario where the zebra mussel was once the most abundant dreissenid; this trend parallels that observed for dreissenid populations in the Dneiper River basin in the Ukraine.

  17. Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    Placzek, Christa; Quade, Jay; Betancourt, Julio L.

    2001-09-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

  18. Assessment of Wetland Hydrological Dynamics in a Modified Catchment Basin: Case of Lake Buninjon, Victoria, Australia.

    Yihdego, Yohannes; Webb, John A

    2017-02-01

      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.

  19. Holocene lake-level fluctuations of Lake Aricota, Southern Peru

    Placzek, C.; Quade, Jay; Betancourt, J.L.

    2001-01-01

    Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

  20. Lake-tilting investigations in southern Sweden

    Paasse, T.

    1996-04-01

    The main aim of lake-tilting investigations is to determine the course of the glacio-isostatic uplift, i.e. to find a formula for the uplift. Besides the lake-tilting graphs, knowledge of the recent relative uplift and the gradient of some marine shorelines are used for solving this problem. This paper summarizes four investigations. 23 refs, 10 figs

  1. Molecular Detection of Tick-Borne Pathogen Diversities in Ticks from Livestock and Reptiles along the Shores and Adjacent Islands of Lake Victoria and Lake Baringo, Kenya

    David Omondi

    2017-06-01

    Full Text Available Although diverse tick-borne pathogens (TBPs are endemic to East Africa, with recognized impact on human and livestock health, their diversity and specific interactions with tick and vertebrate host species remain poorly understood in the region. In particular, the role of reptiles in TBP epidemiology remains unknown, despite having been implicated with TBPs of livestock among exported tortoises and lizards. Understanding TBP ecologies, and the potential role of common reptiles, is critical for the development of targeted transmission control strategies for these neglected tropical disease agents. During the wet months (April–May; October–December of 2012–2013, we surveyed TBP diversity among 4,126 ticks parasitizing livestock and reptiles at homesteads along the shores and islands of Lake Baringo and Lake Victoria in Kenya, regions endemic to diverse neglected tick-borne diseases. After morphological identification of 13 distinct Rhipicephalus, Amblyomma, and Hyalomma tick species, ticks were pooled (≤8 individuals by species, host, sampling site, and collection date into 585 tick pools. By supplementing previously established molecular assays for TBP detection with high-resolution melting analysis of PCR products before sequencing, we identified high frequencies of potential disease agents of ehrlichiosis (12.48% Ehrlichia ruminantium, 9.06% Ehrlichia canis, anaplasmosis (6.32% Anaplasma ovis, 14.36% Anaplasma platys, and 3.08% Anaplasma bovis,, and rickettsiosis (6.15% Rickettsia africae, 2.22% Rickettsia aeschlimannii, 4.27% Rickettsia rhipicephali, and 4.95% Rickettsia spp., as well as Paracoccus sp. and apicomplexan hemoparasites (0.51% Theileria sp., 2.56% Hepatozoon fitzsimonsi, and 1.37% Babesia caballi among tick pools. Notably, we identified E. ruminantium in both Amblyomma and Rhipicephalus pools of ticks sampled from livestock in both study areas as well as in Amblyomma falsomarmoreum (66.7% and Amblyomma nuttalli (100

  2. Molecular Detection of Tick-Borne Pathogen Diversities in Ticks from Livestock and Reptiles along the Shores and Adjacent Islands of Lake Victoria and Lake Baringo, Kenya.

    Omondi, David; Masiga, Daniel K; Fielding, Burtram C; Kariuki, Edward; Ajamma, Yvonne Ukamaka; Mwamuye, Micky M; Ouso, Daniel O; Villinger, Jandouwe

    2017-01-01

    Although diverse tick-borne pathogens (TBPs) are endemic to East Africa, with recognized impact on human and livestock health, their diversity and specific interactions with tick and vertebrate host species remain poorly understood in the region. In particular, the role of reptiles in TBP epidemiology remains unknown, despite having been implicated with TBPs of livestock among exported tortoises and lizards. Understanding TBP ecologies, and the potential role of common reptiles, is critical for the development of targeted transmission control strategies for these neglected tropical disease agents. During the wet months (April-May; October-December) of 2012-2013, we surveyed TBP diversity among 4,126 ticks parasitizing livestock and reptiles at homesteads along the shores and islands of Lake Baringo and Lake Victoria in Kenya, regions endemic to diverse neglected tick-borne diseases. After morphological identification of 13 distinct Rhipicephalus, Amblyomma , and Hyalomma tick species, ticks were pooled (≤8 individuals) by species, host, sampling site, and collection date into 585 tick pools. By supplementing previously established molecular assays for TBP detection with high-resolution melting analysis of PCR products before sequencing, we identified high frequencies of potential disease agents of ehrlichiosis (12.48% Ehrlichia ruminantium , 9.06% Ehrlichia canis ), anaplasmosis (6.32% Anaplasma ovis , 14.36% Anaplasma platys , and 3.08% Anaplasma bovis ,), and rickettsiosis (6.15% Rickettsia africae , 2.22% Rickettsia aeschlimannii , 4.27% Rickettsia rhipicephali , and 4.95% Rickettsia spp.), as well as Paracoccus sp. and apicomplexan hemoparasites (0.51% Theileria sp., 2.56% Hepatozoon fitzsimonsi , and 1.37% Babesia caballi ) among tick pools. Notably, we identified E. ruminantium in both Amblyomma and Rhipicephalus pools of ticks sampled from livestock in both study areas as well as in Amblyomma falsomarmoreum (66.7%) and Amblyomma nuttalli (100%) sampled

  3. DNA barcoding of schistosome cercariae reveals a novel sub-lineage within Schistosoma rodhaini from Ngamba Island Chimpanzee Sanctuary, Lake Victoria.

    Standley, C J; Stothard, J R

    2012-10-01

    While Schistosoma rodhaini is typically considered a parasite of small mammals and is very scantly distributed in the Lake Victoria basin, it is known to hybridize with the more widespread Schistosoma mansoni, the causative agent of intestinal schistosomiasis. As part of broader parasitological and malacological surveys for S. mansoni across Lake Victoria, schistosome cercariae were harvested from a field-caught Biomphalaria choanomphala taken on Ngamba Island Chimpanzee Sanctuary, Uganda. Upon DNA barcoding, these cercariae were found to be a mixture of both S. rodhaini and S. mansoni, with further phylogenetic analysis revealing a hitherto unknown sub-lineage within S. rodhaini. Despite repeated sampling for eggs and miracidia from both chimpanzees and staff on Ngamba Island Sanctuary, detection of S. rodhaini within local definitive hosts awaits additional efforts, which should be mindful of a potential host role of spotted-necked otters.

  4. Genetic variation and demographic history of the Haplochromis laparogramma group of Lake Victoria-An analysis based on SINEs and mitochondrial DNA.

    Mzighani, Semvua I; Nikaido, Masato; Takeda, Miyuki; Seehausen, Ole; Budeba, Yohana L; Ngatunga, Benjamin P; Katunzi, Egid F B; Aibara, Mitsuto; Mizoiri, Shinji; Sato, Tetsu; Tachida, Hidenori; Okada, Norihiro

    2010-01-15

    More than 500 endemic haplochromine cichlid species inhabit Lake Victoria. This striking species diversity is a classical example of recent explosive adaptive radiation thought to have happened within the last approximately 15,000 years. In this study, we examined the population structure and historical demography of 3 pelagic haplochromine cichlid species that resemble in morphology and have similar niche, Haplochromis (Yssichromis) laparogramma, Haplochromis (Y.) pyrrhocephalus, and Haplochromis (Y.) sp. "glaucocephalus". We investigated the sequences of the mitochondrial DNA control region and the insertion patterns of short interspersed elements (SINEs) of 759 individuals. We show that sympatric forms are genetically differentiated in 4 of 6 cases, but we also found apparent weakening of the genetic differentiation in areas with turbid water. We estimated the timings of population expansion and species divergence to coincide with the refilling of the lake at the Pleistocene/Holocene boundary. We also found that estimates can be altered significantly by the choice of the shape of the molecular clock. If we employ the nonlinear clock model of evolutionary rates in which the rates are higher towards the recent, the population expansion was dated at around the event of desiccation of the lake ca. 17,000 YBP. Thus, we succeeded in clarifying the species and population structure of closely related Lake Victoria cichlids and in showing the importance of applying appropriate clock calibrations in elucidating recent evolutionary events.

  5. Parasitic infections on the shore of Lake Victoria (East Africa) detected by Mini-FLOTAC and standard techniques.

    Barda, Beatrice; Ianniello, Davide; Zepheryne, Henry; Rinaldi, Laura; Cringoli, Giuseppe; Burioni, Roberto; Albonico, Marco

    2014-09-01

    Helminths and protozoa infections pose a great burden especially in developing countries, due to morbidity caused by both acute and chronic infection. The aim of our survey was to analyze the intestinal parasitic burden in communities from Mwanza region, Tanzania. Subjects (n=251) from four villages on the South of Lake Victoria have been analyzed for intestinal parasites with direct smear (DS), formol-ether concentration method (FECM) and the newly developed Mini-FLOTAC technique; urinary schistosomiasis was also assessed in a subsample (n=151); symptoms were registered and correlation between clinic and infections was calculated by chi-squared test and logistical regression. Out of the subjects screened for intestinal and for urinary parasites, 87% (218/251) were found positive for any infection, 69% (174/251) carried a helminthic and 67% (167/251) a protozoan infection, almost half of them had a double or triple infection. The most common helminths were hookworms, followed by Schistosoma mansoni and Schistosoma haematobium. Among protozoa, the most common was Entamoeba coli followed by Entamoeba histolytica/dispar and Giardia intestinalis. Mini-FLOTAC detected a number of helminth infections (61.7%) higher than FECM (38.6%) and DS (17.9%). Some positive associations with abdominal symptoms were found and previous treatment was negatively correlated with infection. Despite the limited size of the examined population the current study indicates a high prevalence of intestinal parasitic infection in Bukumbi area, Tanzania, and Mini-FLOTAC showed to be a promising diagnostic tool for helminth infections. This high parasitic burden calls for starting a regular deworming programme and other preventive interventions in schools and in the community. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Integrated prevalence mapping of schistosomiasis, soil-transmitted helminthiasis and malaria in lakeside and island communities in Lake Victoria, Uganda

    2011-01-01

    Background It is widely advocated that integrated strategies for the control of neglected tropical diseases (NTDs) are cost-effective in comparison to vertical disease-specific programmes. A prerequisite for implementation of control interventions is the availability of baseline data of prevalence, including the population at risk and disease overlap. Despite extensive literature on the distribution of schistosomiasis on the mainland in Uganda, there has been a knowledge gap for the prevalence of co-infections with malaria, particularly for island communities in Lake Victoria. In this study, nine lakeshore and island districts were surveyed for the prevalence of NTDs and malaria, as well as educational and health infrastructure. Results A total of 203 communities were surveyed, including over 5000 school-age children. Varying levels of existing health infrastructure were observed between districts, with only Jinja District regularly treating people for NTDs. Community medicine distributors (CMD) were identified and trained in drug delivery to strengthen capacity. Prevalence levels of intestinal schistosomiasis and soil-transmitted helminthiasis were assessed via Kato-Katz thick smears of stool and malaria prevalence determined by microscopy of fingerprick blood samples. Prevalence levels were 40.8%, 26.04% and 46.4%, respectively, while the prevalence of co-infection by Schistosoma mansoni and Plasmodium spp. was 23.5%. Socio-economic status was strongly associated as a risk factor for positive infection status with one or more of these diseases. Conclusions These results emphasise the challenges of providing wide-scale coverage of health infrastructure and drug distribution in remote lakeshore communities. The data further indicate that co-infections with malaria and NTDs are common, implying that integrated interventions for NTDs and malaria are likely to maximize cost-effectiveness and sustainability of disease control efforts. PMID:22166365

  7. Perceptions of HIV and Safe Male Circumcision in High HIV Prevalence Fishing Communities on Lake Victoria, Uganda.

    Paul E Nevin

    Full Text Available In 2010, the Uganda Ministry of Health introduced its Safe Male Circumcision (SMC strategy for HIV prevention with the goal of providing 4.2 million voluntary medical male circumcisions by 2015. Fishing communities, where HIV prevalence is approximately 3-5 times higher than the national average, have been identified as a key population needing targeted HIV prevention services by the National HIV Prevention Strategy. This study aimed to understand perceptions of HIV and identify potential barriers and facilitators to SMC in fishing communities along Lake Victoria.We conducted 8 focus group discussions, stratified by sex and age, with 67 purposefully sampled participants in 4 communities in Kalangala District, Uganda.There was universal knowledge of the availability of SMC services, but males reported high uptake in the community while females indicated that it is low. Improved hygiene, disease prevention, and improved sexual performance and desirability were reported facilitators. Barriers included a perceived increase in SMC recipients' physiological libido, post-surgical abstinence, lost income during convalescence, and lengthier recovery due to occupational hazards. Both males and females reported concerns about spousal fidelity during post-SMC abstinence. Reported misconceptions and community-held cultural beliefs include fear that foreskins are sold after their removal, the belief that a SMC recipient's first sexual partner after the procedure should not be his spouse, and the belief that vaginal fluids aid circumcision wound healing.Previous outreach efforts have effectively reached these remote communities, where availability and health benefits of SMC are widely understood. However, community-specific intervention strategies are needed to address the barriers identified in this study. We recommend the development of targeted counseling, outreach, and communication strategies to address barriers, misconceptions, and community-held beliefs

  8. Integrated prevalence mapping of schistosomiasis, soil-transmitted helminthiasis and malaria in lakeside and island communities in Lake Victoria, Uganda.

    Kabatereine, Narcis B; Standley, Claire J; Sousa-Figueiredo, Jose C; Fleming, Fiona M; Stothard, J Russell; Talisuna, Ambrose; Fenwick, Alan

    2011-12-13

    It is widely advocated that integrated strategies for the control of neglected tropical diseases (NTDs) are cost-effective in comparison to vertical disease-specific programmes. A prerequisite for implementation of control interventions is the availability of baseline data of prevalence, including the population at risk and disease overlap. Despite extensive literature on the distribution of schistosomiasis on the mainland in Uganda, there has been a knowledge gap for the prevalence of co-infections with malaria, particularly for island communities in Lake Victoria. In this study, nine lakeshore and island districts were surveyed for the prevalence of NTDs and malaria, as well as educational and health infrastructure. A total of 203 communities were surveyed, including over 5000 school-age children. Varying levels of existing health infrastructure were observed between districts, with only Jinja District regularly treating people for NTDs. Community medicine distributors (CMD) were identified and trained in drug delivery to strengthen capacity. Prevalence levels of intestinal schistosomiasis and soil-transmitted helminthiasis were assessed via Kato-Katz thick smears of stool and malaria prevalence determined by microscopy of fingerprick blood samples. Prevalence levels were 40.8%, 26.04% and 46.4%, respectively, while the prevalence of co-infection by Schistosoma mansoni and Plasmodium spp. was 23.5%. Socio-economic status was strongly associated as a risk factor for positive infection status with one or more of these diseases. These results emphasise the challenges of providing wide-scale coverage of health infrastructure and drug distribution in remote lakeshore communities. The data further indicate that co-infections with malaria and NTDs are common, implying that integrated interventions for NTDs and malaria are likely to maximize cost-effectiveness and sustainability of disease control efforts.

  9. Comparing insecticide-treated bed net use to Plasmodium falciparum infection among schoolchildren living near Lake Victoria, Kenya.

    Okoyo, Collins; Mwandawiro, Charles; Kihara, Jimmy; Simiyu, Elses; Gitonga, Caroline W; Noor, Abdisalan M; Njenga, Sammy M; Snow, Robert W

    2015-12-22

    Under trial conditions insecticide-treated nets have been shown to provide significant clinical and mortality protection under a range of malaria transmission intensity conditions. There are, however, few operational impact data, notably in very intense transmission conditions. This study, reports on malaria infection among Kenyan schoolchildren living in areas of intense malaria transmission and their reported use of insecticide-treated bed nets. 5188 children in 54 schools were randomly sampled from seven counties surrounding Lake Victoria between May and June 2014. A questionnaire was administered to schoolchildren in classes 2-6 on the use of a long-lasting, insecticide-treated net (LLIN) the night before the survey and provided a single blood sample for a rapid diagnostic test for malaria infection. Analysis of the impact of insecticide-treated net use on malaria prevalence was undertaken using a multivariable, mixed effects, logistic regression at 95% confidence interval (CI), taking into account hierarchical nature of the data and results adjusted for school clusters. The overall prevalence of malaria infection was 48.7%, two-thirds (67.9%) of the children reported using LLIN, 91.3% of the children reported that their households own at least one LLIN and the household LLIN coverage was 2.5 persons per one LLIN. The prevalence of infection showed variation across the counties, with prevalence being highest in Busia (66.9%) and Homabay (51.8%) counties, and lowest in Migori County (29.6%). Generally, malaria parasite prevalence differed between age groups and gender with the highest prevalence occurring in children below 7 years (50.6%) and males (52.2%). Adjusting for county and school, there was a significant reduction in odds of malaria infection among the schoolchildren who reported LLIN use the previous night by 14 % (aOR 0.86, 95% CI 0.74-0.98, P provide protection against infection among school-aged children.

  10. Population dynamics of Glossina fuscipes fuscipes on Buvuma Island, Lake Victoria, Uganda

    Ogwal, L.M.; Kangwagye, T.N.

    1990-01-01

    A survey made of Buvuma Island to establish the incidence, distribution and population dynamics of tsetse flies showed that Glossina fuscipes fuscipes Newstead was the most abundant species. This species occurred in the southeastern, western and northern parts of the island. Although the fly is both riverine and peridomestic in its habits, the survey revealed that its population was concentrated mainly within a distance of about 2 km from the lake shores around houses, in banana plantations, at forest edges and roadsides, in fishing villages and ports of call, on grazing grounds and at water collection points. Studies of the population dynamics revealed seasonal variations in the abundance of the species, with a peak during the main dry season, i.e. in the months of January and February. The breeding peak was reached during the minor rainy season. Trap catches were highest in fishing villages and ports of call, followed in decreasing order by catches at forest edge and roadside locations, at water collection points, around houses, in banana plantations and on grazing grounds. It appears that the fishing villages and ports of call were possibly the most suitable breeding grounds. The efficiency of the traps was reflected in the fact that G. f. fuscipes populations were reduced by up to 95% in Tome and 90% in the Bulopa-Walwanda and Lwenyanja villages. Many puparia were also found on the sandy beaches around fishing villages and ports of call. There was evidence of fly movement between the islands and the mainland, indicating that, although geographically isolated, Buvuma Island is not isolated from the mainland in terms of tsetse fly movement. (author). 21 refs, 5 figs, 1 tab

  11. Do religion and religiosity have anything to do with alcohol consumption patterns? Evidence from two fish landing sites on Lake Victoria Uganda.

    Tumwesigye, Nazarius M; Atuyambe, Lynn; Kibira, Simon P S; Wabwire-Mangen, Fred; Tushemerirwe, Florence; Wagner, Glenn J

    2013-09-01

    Fish landing sites have high levels of harmful use of alcohol. This paper examines the role of religion and religiosity on alcohol consumption at two fish landing sites on Lake Victoria in Uganda. Questionnaires were administered to randomly selected people at the sites. Dependent variables included alcohol consumption during the previous 30 days, whereas the key independent variables were religion and religiosity. Bivariate and multivariate analysis techniques were applied. People reporting low religiosity were five times more likely to have consumed alcohol (95% confidence interval: 2.45-10.04) compared with those reporting low/average religiosity. Religion and religiosity are potential channels for controlling alcohol use.

  12. Granitoids of the Dry Valleys area, southern Victoria Land : geochemistry and evolution along the early Paleozoic Antarctic Craton margin

    Allibone, A.H.; Cox, S.C.; Smillie, R.W.

    1993-01-01

    Field relationships and geochemistry indicate granitoid plutons of the Dry Valleys area comprise at least three petrogenetically distinct suites. The older Dry Valleys 1a (DV1a) suite, comprising the Bonney, Catspaw, Denton, Cavendish, and Wheeler Plutons and hornblende-biotite orthogneisses, and Dry Valleys 1b (DV1b) suite, comprising the Hedley, Valhalla, St Johns, Dun, Calkin, and Suess Plutons, biotite granitoid dikes and biotite orthogneisses, were emplaced before prominent swarms of Vanda mafic and felsic dikes. Both the DV1a and DV1b suites are time transgressive, with older intrusions in each suite being emplaced during the later stages of deformation of the Koettlitz Group. Younger granitoids that postdate the majority of the Vanda dikes include: the Dry Valleys 2 (DV2) suite, comprising the Pearse and Nibelungen Plutons plus several smaller, unnamed plugs; and the Harker, Swinford, Orestes, and Brownworth Plutons with identical field relationships and enclaves but distinct chemistries. Chemical characteristics and limited Rb-Sr isotopic dating indicate plutonism before c. 500 Ma was dominated by the Cordilleran I-type DV1a suite, inferred to have developed during melting above a west-dipping subduction zone along the Antarctic Craton margin. The chemical characteristics of the DV1b suite indicate large-scale melting of a quartzo-feldspathic protolith lacking residual plagioclase, but containing refractory garnet. Potential DV1b suite source rocks include metamorphosed immature sediments, possibly underplated along the subduction zone associated with DV1a magmatism, or older granitoid orthogneisses. Major DV1b plutonism at 490 Ma marks the end of subduction-related plutonism in southern Victoria Land. Younger DV2 alkali-calcic, Caledonian I-type plutonism is inferred to have formed in response to uplift and extension between 480 and 455 Ma. Lack of DV2 suite correlatives and Vanda mafic and felsic dikes in northern Victoria Land suggests significantly

  13. Retention efficiencies of halogenated and non-halogenated hydrocarbons in selected wetland ecosystem in Lake Victoria Basin

    Shadrack Mule

    2015-06-01

    Full Text Available The determination of retention efficiencies of halogenated and non-halogenated hydrocarbon in selected wetland ecosystems in Lake Victoria basin was carried out. Qualitative and quantitative determination of the presence of residual hydrocarbons in Kigwal/Kimondi, Nyando and Nzoia wetland ecosystems using Gas Chromatography - Mass Spectrometer (GC-MS instrument indicated the presence of residual organochlorines, organophosphorus, carbamates and synthetic pyrethroid hydrocarbons in water, sediment and plant materials. In order to compare the retention efficiencies of the wetlands, the wetland ecosystems were divided into three different sections, namely: inlet, mid and outlet. Calculations of mass balances of residual halogenated and non-halogenated hydrocarbons at the respective sections was done taking into account the partition of the studied compounds in samples of water, sediments and papyrus reed plant materials and analyzed using validated Gas Chromatography - Mass Spectrometer (GC-MS method. From the analysis, several residual hydrocarbons namely: bendiocarb, benzene hexachloride (BHC, carbaryl, cypermethrin, decis, deltamethrin, diazinon, dieldrin, DDT, DDD, DDE, malathion, propoxur, sumithion, 5-phenylrhodanine, 1,3,5-trichlorobenzene, 1-(2-phenoxybenzylhydrazine were detected and quantified. The levels of the selected residual hydrocarbons in water samples were used to calculate the retention efficiencies of a specific hydrocarbon and the values recorded. Generally, River Nyando wetland recorded mean percentage retention efficiencies of 76 and 94% for dry and rainy seasons respectively; Kigwal/Kimondi wetland had seasonal mean percentage retention efficiencies of 63 to 78%. River Nzoia also had calculated seasonal mean percentage retention efficiencies of between 56 to 88%. Dry season had lower mean percentages retention efficiencies as compared to rainy season in the three wetlands of interest during the period of study. The study

  14. Factors associated with dropout in a long term observational cohort of fishing communities around lake Victoria, Uganda.

    Abaasa, Andrew; Asiki, Gershim; Mpendo, Juliet; Levin, Jonathan; Seeley, Janet; Nielsen, Leslie; Ssetaala, Ali; Nanvubya, Annet; De Bont, Jan; Kaleebu, Pontiano; Kamali, Anatoli

    2015-12-24

    Fishing communities are potentially suitable for Human immunodeficiency virus (HIV) efficacy trials due to their high risk profile. However, high mobility and attrition could decrease statistical power to detect the impact of a given intervention. We report dropout and associated factors in a fisher-folk observational cohort in Uganda. Human immunodeficiency virus-uninfected high-risk volunteers aged 13-49 years living in five fishing communities around Lake Victoria were enrolled and followed every 6 months for 18 months at clinics located within each community. Volunteers from two of the five communities had their follow-up periods extended to 30 months and were invited to attend clinics 10-40 km (km) away from their communities. Human immunodeficiency virus counseling and testing was provided, and data on sexual behaviour collected at all study visits. Study completion was defined as completion of 18 or 30 months or visits up to the date of sero-conversion and dropout as missing one or more visits. Discrete time survival models were fitted to find factors independently associated with dropout. A total of 1000 volunteers (55% men) were enrolled. Of these, 91.9% completed 6 months, 85.2% completed 12 months and 76.0% completed 18 months of follow-up. In the two communities with additional follow-up, 76.9% completed 30 months. In total 299 (29.9%) volunteers missed at least one visit (dropped out). Dropout was independently associated with age (volunteers aged 13-24 being most likely to dropout), gender [men being more likely to dropout than women [adjusted hazard ratio (aHR) 1.4; 95% confidence interval (CI) 1.1-1.8)], time spent in the fishing community (those who stayed dropout), History of marijuana use (users being more likely to dropout than non-users [1.7; (1.2-2.5)], ethnicity (non-Baganda being more likely to dropout than Baganda [1.5; (1.2-1.9)], dropout varied between the five fishing communities, having a new sexual partner in the previous 3 months [1

  15. Linking Land Use Changes to Surface Water Quality Variability in Lake Victoria: Some Insights From Remote Sensing (GC41B-1101)

    Limaye, Ashutosh; Mugo, Robinson; Wanjohi, James; Farah, Hussein; Wahome, Anastasia; Flores, Africa; Irwin, Dan

    2016-01-01

    Various land use changes driven by urbanization, conversion of grasslands and woodlands into farmlands, intensification of agricultural practices, deforestation, land fragmentation and degradation are taking place in Africa. In Kenya, agriculture is the main driver of land use conversions. The impacts of these land use changes are observable in land cover maps, and eventually in the hydrological systems. Reduction or change of natural vegetation cover types increases the speed of surface runoff and reduces water and nutrient retention capacities. This can lead to high nutrient inputs into lakes, resulting in eutrophication, siltation and infestation of floating aquatic vegetation. To assess if changes in land use could be contributing to increased phytoplankton blooms and sediment loads into Lake Victoria, we analyzed land use land cover data from Landsat, as well as surface chlorophyll-a and total suspended matter from MODIS-Aqua sensor.

  16. Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya’s Lakes Victoria and Baringo

    Ajamma, Yvonne Ukamaka; Villinger, Jandouwe; Omondi, David; Salifu, Daisy; Onchuru, Thomas Ogao; Njoroge, Laban; Muigai, Anne W. T.; Masiga, Daniel K.

    2016-01-01

    The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock. PMID:27402888

  17. A preliminary magnetic study of Sawa lake sediments, Southern Iraq

    Ameen, Nawrass

    2016-04-01

    A preliminary magnetic study combined with chemical analyses was carried out in Sawa Lake in Al-Muthanna province, southern Iraq, about 22 km south west of Samawa city (31°18'48.80"N, 45°0'25.25"E). The lake is about 4.74 km length, 1.75 km width and 5.5 m height, it is surrounded by a salt rim which is higher than the lake water by about 2.8 m and sea water by about 18.5 m (Naqash et al., 1977 in Hassan, 2007). The lake is an elongated closed basin with no surface water available to it, it may be fed by groundwater of the Euphrates and Dammam aquifers through system of joints and cracks. This study aims to investigate the concentrations of selected heavy metals as pollutants and magnetic susceptibility (MS) and other magnetic properties of sediment samples from fifty sites collected from the bottom of the lake, the study area lies in an industrial area. The results show spatial variations of MS with mean value of about 4.58 x 10-8 m3 kg-1. Scanning electron microscopy and magnetic mineralogy parameters indicate the dominance of soft magnetic phase like magnetite and presence of hard magnetic phase like hematite. Spatial variations of MS combined with the concentrations of heavy metals suggests the efficiency of magnetic methods as effective, inexpensive and non-time consuming method to outlining the heavy metal pollution. References: Hassan W.F., 2007. The Physio-chemical characteristic of Sawa lake water in Samawa city-Iraq. Marine Mesopotamica, 22(2), 167-179.

  18. Hydro-climatic trends and water resource management implications based on multi-scale data for the Lake Victoria region, Kenya

    Koutsouris, A J; Destouni, G; Jarsjoe, J; Lyon, S W

    2010-01-01

    Unreliable rainfall may be a main cause of poverty in rural areas, such as the Kisumu district by Lake Victoria in Kenya. Climate change may further increase the negative effects of rainfall uncertainty. These effects could be mitigated to some extent through improved and adaptive water resource management and planning, which relies on our interpretations and projections of the coupled hydro-climatic system behaviour and its development trends. In order to identify and quantify the main differences and consistencies among such hydro-climatic assessments, this study investigates trends and exemplifies their use for important water management decisions for the Lake Victoria drainage basin (LVDB), based on local scale data for the Orongo village in the Kisumu district, and regional scale data for the whole LVDB. Results show low correlation between locally and regionally observed hydro-climatic trends, and large differences, which in turn affects assessments of important water resource management parameters. However, both data scales converge in indicating that observed local and regional hydrological discharge trends are primarily driven by local and regional water use and land use changes.

  19. Diatom Assemblage in the Lake of Gaber Oun, Southern Libya

    Abdelkader Elzen

    2012-07-01

    Full Text Available The lake of Gaber Oun in the southern district of Libya was studied to assess the diatom community composition in the littoral zone. Planktic and attached diatoms were listed and information on the constituent species made known (images are shown. Some criteria of the water characteristics are also given such as the pH, which is an average of 8.3, electrical conductivity which accounted for 1.4 µSim/cm1- and total dissolved salts (TDS of 189.0 mg/L1-.

  20. The patterns and trends of marketing and consumption of the fish of Lake Victoria (Kenya waters). Paper presented at FISA 95: Inaugural Congress of the Fisheries Society for Africa (FISA '95),UNEP Nairobi, Kenya, 31 July - 5th August, 1995.

    Abila, R.

    1995-01-01

    Lake Victoria, producing over 90% of Kenya's fish, is the principle source of fish for domestic consumption and for export in the country. The three fish species of most economic importance are Lates niloticus, Rastrineobola argentea and Oreochromis species. These constitute 50%, 37% and 6% respectively of the lakes's tonnage. The structure and performance of the marketing system for each of these species differ, depending on certain market features. Among these are the marketing history and ...

  1. An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

    Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

    2011-01-01

    The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that

  2. Comparative analysis of discharges into Lake Michigan, Phase I - Southern Lake Michigan.

    Veil, J. A.; Elcock, D.; Gasper, J. R.; Environmental Science Division

    2008-06-30

    BP Products North America Inc. (BP) owns and operates a petroleum refinery located on approximately 1,700 acres in Whiting, East Chicago, and Hammond, Indiana, near the southern tip of Lake Michigan. BP provided funding to Purdue University-Calumet Water Institute (Purdue) and Argonne National Laboratory (Argonne) to conduct studies related to wastewater treatment and discharges. Purdue and Argonne are working jointly to identify and characterize technologies that BP could use to meet the previous discharge permit limits for total suspended solids (TSS) and ammonia after refinery modernization. In addition to the technology characterization work, Argonne conducted a separate project task, which is the subject of this report. In Phase I of a two-part study, Argonne estimated the current levels of discharge to southern Lake Michigan from significant point and nonpoint sources in Illinois, Indiana, and portions of Michigan. The study does not consider all of the chemicals that are discharged. Rather, it is narrowly focused on a selected group of pollutants, referred to as the 'target pollutants'. These include: TSS, ammonia, total and hexavalent chromium, mercury, vanadium, and selenium. In Phase II of the study, Argonne will expand the analysis to cover the entire Lake Michigan drainage basin.

  3. High concentrations of polycyclic aromatic hydrocarbons found in water and sediments of car wash and Kisat areas of Winam Gulf, Lake Victoria-Kenya.

    Kwach, B O; Lalah, J O

    2009-11-01

    Mean concentrations of selected USEPA priority polycyclic aromatic hydrocarbons (PAHs) in surface sediments and water samples from Car Wash and Kisat areas of Winam Gulf, Lake Victoria in Kenya have been determined using GC-FID and GC-MS. Sampling was done during the rainy season in April 2006. The PAH concentrations in sediment and water ranged from 0.04 to 31.95 microg/g dry weight and 3.32 to 55.8 microg/L, respectively, depending upon the sampling location. The total concentration levels of PAHs in both the sediment and water phase in this study were found to be much higher compared with those reported from other regions worldwide, revealing significant PAH pollution of Car Wash and Kisat areas of Kisumu city bay as a consequent of anthropogenic activities as described in the text. The GC-detected PAHs were confirmed by GC-MS.

  4. Spartial and seasonal variations in concentrations of polycyclic aromatic hydrocarbons in water and sediment of Kisumu City bay of Winam Gulf, Lake Victoria-Kenya.

    Kwach, Bowa O; Lalah, Joseph O; Shem, Wandiga O

    2009-11-01

    Seasonal and offshore concentration variations for selected sixteen priority pollutant polycyclic aromatic hydrocarbons (PAHs) in surface sediments and water of Car Wash and Kisat areas of Winam Gulf, Lake Victoria, have been investigated. PAHs concentrations in sediments and water range from 0.4 to 31.95 microg/g dry weight and 3.32 to 55.8 microg/L, respectively. Statistical analysis of the PAHs concentrations showed that the most contaminated samples are found during rainy season (April, 2006), 5 m offshore for sediments and 10 m offshore for water. Dry season (October, 2005) generally recorded lower concentrations. The variations showed significant difference (p < or = 0.05) with season and distance of sampling from the shore.

  5. New insight into defining the lakes of the southern Baltic coastal zone.

    Cieśliński, Roman; Olszewska, Alicja

    2018-01-29

    There exist many classification systems of hydrographic entities such as lakes found along the coastlines of seas and oceans. Each system has its advantages and can be used with some success in the area of protection and management. This paper aims to evaluate whether the studied lakes are only coastal lakes or rather bodies of water of a completely different hydrological and hydrochemical nature. The attempt to create a new classification system of Polish coastal lakes is related to the incompleteness of lake information in existing classifications. Thus far, the most frequently used are classifications based solely on lake basin morphogenesis or hydrochemical properties. The classifications in this paper are based not only on the magnitude of lake water salinity or hydrochemical analysis but also on isolation from the Baltic Sea and other sources of water. The key element of the new classification system for coastal bodies of water is a departure from the existing system used to classify lakes in Poland and the introduction of ion-"tracking" methods designed to identify anion and cation distributions in each body of water of interest. As a result of the work, a new classification of lakes of the southern Baltic Sea coastal zone was created. Featured objects such as permanently brackish lakes, brackish lakes that may turn into freshwater lakes from time to time, freshwater lakes that may turn into brackish lakes from time to time, freshwater lakes that experience low levels of salinity due to specific incidents, and permanently freshwater lakes. The authors have adopted 200 mg Cl -  dm -3 as a maximum value of lake water salinity. There are many conditions that determine the membership of a lake to a particular group, but the most important is the isolation lakes from the Baltic Sea. Changing a condition may change the classification of a lake.

  6. Water pollution and cyanobacteria's variation of rivers surrounding southern Taihu Lake, China.

    Sun, Mingyang; Huang, Linglin; Tan, Lisha; Yang, Zhe; Baig, Shams Ali; Sheng, Tiantian; Zhu, Hong; Xu, Xinhua

    2013-05-01

    The water quality and cyanobacterial variation of rivers surrounding southern Taihu Lake, China were purposively monitored from 2008 to 2010. Trophic level index (TLI) was used to evaluate the trophic levels of southern Taihu Lake. Results showed a considerable decline in the monitored data compared with 2007, and the data showed downward trends year after year. The TLI decreased from 55.6 to 51.3, which implied that southern Taihu Lake was mildly eutrophic. The water quality and cyanobacterial variation indicated a positive response to the adopted control measures in the southern Taihu Lake basin, but the intra- and inter-annual variability was still quite varied. High concentrations of nitrogen and phosphorus typically lead to algae outbreaks, however, the cyanobacteria growth may result in a decline of the concentration of nitrogen and phosphorus. Temperature and other weather conditions are also important factors for algae outbreaks; the risk of blue-green algal blooms still persists.

  7. Cisco (Coregonus artedii) mortalities in a southern Michigan lake, July 1968

    Colby, Peter J.; Brooke, Larry T.

    1969-01-01

    Cisco die-offs are common in the summer in certain lakes of northern Indiana and southern Michigan, along the southern boundary of the national distribution of coregonine fishes. Although numerous cisco die-offs have been reported, few, if any, have been accompanied by environmental information at the time of the die-off. On 31 July and 1 August 1968, we investigated a cisco die-off on Halfmoon Lake, on the border of Washtenaw and Livingston Counties, Michigan.

  8. Time series analysis of satellite multi-sensors imagery to study the recursive abnormal grow of floating macrophyte in the lake victoria (central Africa)

    Fusilli, Lorenzo; Cavalli, Rosa Maria; Laneve, Giovanni; Pignatti, Stefano; Santilli, Giancarlo; Santini, Federico

    2010-05-01

    Remote sensing allows multi-temporal mapping and monitoring of large water bodies. The importance of remote sensing for wetland and inland water inventory and monitoring at all scales was emphasized several times by the Ramsar Convention on Wetlands and from EU projects like SALMON and ROSALMA, e.g. by (Finlayson et al., 1999) and (Lowry and Finlayson, 2004). This paper aims at assessing the capability of time series of satellite imagery to provide information suitable for enhancing the understanding of the temporal cycles shown by the macrophytes growing in order to support the monitor and management of the lake Victoria water resources. The lake Victoria coastal areas are facing a number of challenges related to water resource management which include growing population, water scarcity, climate variability and water resource degradation, invasive species, water pollution. The proliferation of invasive plants and aquatic weeds, is of growing concern. In particular, let us recall some of the problems caused by the aquatic weeds growing: Ø interference with human activities such as fishing, and boating; Ø inhibition or interference with a balanced fish population; Ø fish killing due to removal of too much oxygen from the water; Ø production of quiet water areas that are ideal for mosquito breeding. In this context, an integrated use of medium/high resolution images from sensors like MODIS, ASTER, LANDSAT/TM and whenever available CHRIS offers the possibility of creating a congruent time series allowing the analysis of the floating vegetation dynamic on an extended temporal basis. Although MODIS imagery is acquired daily, cloudiness and other sources of noise can greatly reduce the effective temporal resolution, further its spatial resolution can results not always adequate to map the extension of floating plants. Therefore, the integrated use of sensors with different spatial resolution, were used to map across seasons the evolution of the phenomena. The

  9. HIV-1 transmission networks in high risk fishing communities on the shores of Lake Victoria in Uganda: A phylogenetic and epidemiological approach.

    Sylvia Kiwuwa-Muyingo

    Full Text Available Fishing communities around Lake Victoria in sub-Saharan Africa have been characterised as a population at high risk of HIV-infection.Using data from a cohort of HIV-positive individuals aged 13-49 years, enrolled from 5 fishing communities on Lake Victoria between 2009-2011, we sought to identify factors contributing to the epidemic and to understand the underlying structure of HIV transmission networks. Clinical and socio-demographic data were combined with HIV-1 phylogenetic analyses. HIV-1 gag-p24 and env-gp-41 sub-genomic fragments were amplified and sequenced from 283 HIV-1-infected participants. Phylogenetic clusters with ≥2 highly related sequences were defined as transmission clusters. Logistic regression models were used to determine factors associated with clustering.Altogether, 24% (n = 67/283 of HIV positive individuals with sequences fell within 34 phylogenetically distinct clusters in at least one gene region (either gag or env. Of these, 83% occurred either within households or within community; 8/34 (24% occurred within household partnerships, and 20/34 (59% within community. 7/12 couples (58% within households clustered together. Individuals in clusters with potential recent transmission (11/34 were more likely to be younger 71% (15/21 versus 46% (21/46 in un-clustered individuals and had recently become resident in the community 67% (14/21 vs 48% (22/46. Four of 11 (36% potential transmission clusters included incident-incident transmissions. Independently, clustering was less likely in HIV subtype D (adjusted Odds Ratio, aOR = 0.51 [95% CI 0.26-1.00] than A and more likely in those living with an HIV-infected individual in the household (aOR = 6.30 [95% CI 3.40-11.68].A large proportion of HIV sexual transmissions occur within house-holds and within communities even in this key mobile population. The findings suggest localized HIV transmissions and hence a potential benefit for the test and treat approach even at a community

  10. Are the Lake Victoria fisheries threatened by exploitation or eutrophication? Towards an ecosystem-based approach to management

    Kolding, J.; Zwieten, van P.A.M.; Mkumbo, O.; Silsbe, G.; Hecky, R.

    2008-01-01

    Lake Victoria’s ecosystem has shown fundamental changes over its past recorded history in terms of nutrient loadings, productivity, faunal composition and fisheries. As yet, however, no attempt has been made to link the driving processes of eutrophication and fisheries to understand the feedback

  11. Fatty Acid Composition and Levels of Selected Polyunsaturated Fatty Acids in Four Commercial Important Freshwater Fish Species from Lake Victoria, Tanzania

    Agnes Robert

    2014-01-01

    Full Text Available Fatty acids (FAs particularly ω3 and ω6 polyunsaturated fatty acids (PUFAs play important role in human health. This study aimed to investigate the composition and levels of selected ω3 PUFAs in four commercial fish species, Nile perch (Lates niloticus, Nile tilapia (Oreochromis niloticus, Tilapia zillii, and dagaa (Rastrineobola argentea from Mwanza Gulf in Lake Victoria. The results indicated that 36 types of FAs with different saturation levels were detected. These FAs were dominated by docosahexaenoic (DHA, eicosapentaenoic (EPA, docosapentaenoic (DPA, and eicosatetraenoic acids. O. niloticus had the highest composition of FAs (34 compared to L. niloticus (27, T. zillii (26, and R. argentea (21. The levels of EPA differed significantly among the four commercial fish species (F=6.19,  P=0.001. The highest EPA levels were found in R. argentea followed by L. niloticus and O. niloticus and the lowest in T. zillii. The DPA levels showed no significant difference among the four fish species studied (F=0.652,  P=0.583. The study concluded that all four commercial species collected from Mwanza Gulf are good for human health, but R. argentea is the best for consumption because it contains higher levels of ω3 FAs, mainly EPA.

  12. Utilisation of Rep-PCR to track microbes in aerosols collected adjacent to their source, a saline lake in Victoria, Australia.

    Munday, Chris I; O'Loingsigh, Tadhg; Tapper, Nigel J; De Deckker, Patrick; Allison, Gwen E

    2013-04-15

    Dust storms are a major source of aerosolized bacteria, especially in the drought conditions experienced in Australia in the decade to 2009. The major aims of this project were to identify the culturable bacteria in environmental samples and to genetically fingerprint all isolates using repetitive element PCR (Rep-PCR) to investigate the possibility of tracking isolates from their source into the atmosphere. Four field trips were conducted to a dry lake in western Victoria, Australia to sample aerosols and sediments. Aerosols were collected at heights up to 150 m using vacuum pumps with filters attached to a tethered helium balloon, while corresponding sediments were collected in sterile polypropylene tubes. Isolates were cultivated on Tryptic Soy Agar, R2 Agar and Marine Agar, and grown in dark conditions at ambient temperature. By sequencing the 16S rRNA gene of 270 isolates, fifteen different bacterial families were identified, with both the aerosols and sediments dominated by the Bacillaceae family. Four sets of Rep-PCR primers were tested, with the ERIC and (GTG)5 primers proving to be the most suitable for fingerprinting the cultured taxa. Rep-PCR revealed very high strain diversity in the samples collected, however some strains were still able to be tracked from sediments up to 150 m in height. This shows the potential of Rep-PCR, however very large reference databases would be required for the technique to be more useful. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Lake size and fish diversity in southern Brazil coastal lagoons

    Lucia Ribeiro Rodrigues

    2015-10-01

    Full Text Available The coastal plain of Rio Grande do Sul, southern Brazil, presents a series of shallow lagoons with diverse size and morphology. The objective of this study is to determine whether the size of the lagoon is an effective factor for structuring fish diversity. In this regard, nine lagoons with distinct areas were sampled: three with an area up to 40 hectares, three with area between 40 and 80 hectares, and three with an area of over 80 hectares. Each lagoon was sampled once on the littoral and pelagic zones. At each point, fish were captured through a set of gill nets with different mesh sizes. Captured specimens were identified, quantified and evaluated for weight and length. A total of 24 fish species belonging to 10 families was obtained, with Characidae presenting the highest species richness. Cyanocharax alburnus was the only species that occurred in all lagoons. Cyphocharax voga, Astyanax eigenmmaniorum, Oligosarcus jenynsii and O. robustus were also frequent species, present in most of the sampled lagoons. Lycengraulis grossidens was captured in just two lagoons with increased conductivity. The community structure showed the highest species richness in lakes with an area over 40 ha, however the highest mean diversity values were observed in ponds up to 40 ha. Cluster Analysis yielded the formation of two groups: a group formed by just one lagoon and a second one cluster grouping all the other lagoons. This pattern may be associated with the presence of Lycengraulis grossidens as a dominant species in this lagoon clustered apart. The results indicate that lagoons with up to 40 ha present greater homogeneity on the species composition and higher average values of diversity; while intermediate ponds (between 40 and 80 ha have lower average diversity for the fish fauna due to increased heterogeneity in species abundance.

  14. Lead-210 analyses of sediment accumulation rates in five Southern Illinois surface mine lakes

    Brugam, R.B.; Carlson, M.A.

    1981-01-01

    210 Pb is a naturally occurring radionuclide with a short half-life (22 yrs) which can be used to determine sedimentation rates in lakes. The technique was applied in 5 Southern Illinois surface mine lakes where it revealed past sedimentation rates to have been extremely variable. In some of the lakes there was evidence for extensive slumping immediately after mining ceased followed by a more regular sedimentary regime that continued until the present. In others there have been one or more changes in sediment accumulation rates since lacustrine sedimentation began. These results suggest that simply measuring the amount of sediment that has accumulated in a surface mine lake since mining ceased is inadequate to determine filling rates. Sedimentation rates in the 5 lakes varied from .60 +- .19 to 1.46 +- .19 cm/y. These rates are similar to natural lakes with moderately disturbed watersheds

  15. A radioanalytical study of radionuclides in a dysoligotrophic lake in Southern Sweden

    Eriksson, M.; Roos, P.; Holm, E.; Peck, G.

    1998-01-01

    Unusually high activity concentration of various artificial radionuclides (from nuclear test fallout and the Chernobyl accident) and some natural radionuclides, have been discovered in lakes with high amounts of humic substances. These lakes tend to have low pH, at times down to pH 5. The lake, Svartsjoen, in the southern part of Sweden is one of these lakes. The food chain and resulting concentration factors in Svartsjoen were investigated and compared to results for other 'normal' lakes. Fish and water samples were collected and analysed for 137 Cs 239+240 Pu, 241 Am and 210 Po during a 4-month visit to Lund. The level of 239/240 Pu in the water of Svartsjoen was found to be elevated. The work on fish from the lake indicates that these elevated levels are not transferred into the food chain. It appears that the humic substances could be blocking plutonium from entering the food chain

  16. Vascular flora of saline lakes in the southern high plains of Texas and eastern New Mexico

    Rosen, David J.; Conway, Warren C.; Haukos, David A.; Caskey, Amber D.

    2013-01-01

    Saline lakes and freshwater playas form the principal surface hydrological feature of the High Plains of the Southern Great Plains. Saline lakes number less than 50 and historically functioned as discharge wetlands with relatively consistent water availability due to the presence of one or more springs. Currently, less than ten saline lakes contain functional springs. A survey of vascular plants at six saline lakes in the Southern High Plains of northwest Texas and one in eastern New Mexico during May and September 2009 resulted in a checklist of 49 species representing 16 families and 40 genera. The four families with the most species were Asteraceae (12), Amaranthaceae (8), Cyperaceae (5), and Poaceae (12). Non-native species (Bromus catharticus, Poa compressa, Polypogon monspeliensis, Sonchus oleraceus, Kochia scoparia, and Tamarix ramosissima) accounted for 10% of the total species recorded. Whereas nearly 350 species of vascular plants have been identified in playas in the Southern High Plains, saline lakes contain a fraction of this species richness. The Southern High Plains saline lake flora is regionally unique, containing taxa not found in playas, with species composition that is more similar to temperate desert wetlands of the Intermountain Region and Gulf Coastal Plain of North America.

  17. Microbial ecology of acid strip mine lakes in southern Indiana

    Gyure, R.A.

    1986-01-01

    In this study, the author examined the limnology and microbial ecology of two acid strip mine lakes in the Greene-Sullivan State Forest near Dugger, Indiana. Reservoir 29 is a larger lake (225 ha) with water column pH of 2.7 and sediment pH of 3.8. Lake B, a smaller (20 ha) lake to the south of Reservoir 29, also has an acidic water column (pH 3.4) but more neutral sediments (pH 6.2). Both have very high sulfate concentrations: 20-30 mM in the water column and as high as 100 mM in the hypolimnion of Lake B. Low allochthonous carbon and nutrient input characterize these lakes as oligotrophic, although algal biomass is higher than would be expected for this trophic status. In both lakes, algal populations are not diverse, with a few species of single-celled Chlorophyta and euglenoids dominating. Algal biomass is concentrated in a thin 10 cm layer at the hypolimnion/metalimnion interface, although light intensity at this depth is low and severely limits productivity. Bacterial activity based on 14 C-glucose incorporation is highest in the hypolimnion of both lakes, and sulfate-reduction is a dominant process in the sediments. Rates of sulfate-reduction compare with those in other freshwater environments, but are not as high as rates measured in high sulfate systems like saltmarsh and marine sediments

  18. Estimation of design floods in ungauged catchments using a regional index flood method. A case study of Lake Victoria Basin in Kenya

    Nobert, Joel; Mugo, Margaret; Gadain, Hussein

    Reliable estimation of flood magnitudes corresponding to required return periods, vital for structural design purposes, is impacted by lack of hydrological data in the study area of Lake Victoria Basin in Kenya. Use of regional information, derived from data at gauged sites and regionalized for use at any location within a homogenous region, would improve the reliability of the design flood estimation. Therefore, the regional index flood method has been applied. Based on data from 14 gauged sites, a delineation of the basin into two homogenous regions was achieved using elevation variation (90-m DEM), spatial annual rainfall pattern and Principal Component Analysis of seasonal rainfall patterns (from 94 rainfall stations). At site annual maximum series were modelled using the Log normal (LN) (3P), Log Logistic Distribution (LLG), Generalized Extreme Value (GEV) and Log Pearson Type 3 (LP3) distributions. The parameters of the distributions were estimated using the method of probability weighted moments. Goodness of fit tests were applied and the GEV was identified as the most appropriate model for each site. Based on the GEV model, flood quantiles were estimated and regional frequency curves derived from the averaged at site growth curves. Using the least squares regression method, relationships were developed between the index flood, which is defined as the Mean Annual Flood (MAF) and catchment characteristics. The relationships indicated area, mean annual rainfall and altitude were the three significant variables that greatly influence the index flood. Thereafter, estimates of flood magnitudes in ungauged catchments within a homogenous region were estimated from the derived equations for index flood and quantiles from the regional curves. These estimates will improve flood risk estimation and to support water management and engineering decisions and actions.

  19. The petrology, geochronology and significance of Granite Harbour Intrusive Complex xenoliths and outcrop sampled in western McMurdo Sound, Southern Victoria Land, Antarctica

    Martin, A.P.; Cooper, A.F.; Price, R.C.; Turnbull, R.E.; Roberts, N.M.W.

    2015-01-01

    Granite Harbour Intrusive Complex xenoliths in McMurdo Volcanic Group rocks and in situ outcrops have been studied from Mount Morning, western McMurdo Sound, Antarctica. Calc-alkalic samples have whole rock signatures and normative compositions similar to the Dry Valleys 1b suite, and zircon grains in one specimen yield a 545.2 ± 4.4 Ma crystallisation age. This supports subduction-related magmatism initiating in Southern Victoria Land by 545 Ma. A second group of xenoliths is alkalic, with titanite grains in one xenolith from this group dated at 538 ± 8 Ma. Whole rock chemistry, normative compositions and geochronology of the alkalic group are comparable to the Koettlitz Glacier Alkaline Suite (KGAS). The position of a proposed lower crustal discontinuity that may form a significant basement suture in the McMurdo Sound region is newly constrained to the east of Mount Morning, perhaps along the trace of the Discovery Glacier. The boundary between East and West Antarctica may also pass along the trace of the Discovery Glacier if, as previously hypothesised, its location is controlled by the basement suture. A significant basement suture may also have provided the necessary egress for the (regionally) early and sustained magmatic activity observed at Mount Morning over the last 24 million years. (author).

  20. Ecosystem effects of thermal manipulation of a whole lake, Lake Breisjøen, southern Norway (THERMOS project)

    Lydersen, E.; Aanes, K. J.; Andersen, S.; Andersen, T.; Brettum, P.; Baekken, T.; Lien, L.; Lindstræm, E. A.; Lævik, J. E.; Mjelde, M.; Oredalen, T. J.; Solheim, A. L.; Romstad, R.; Wright, R. F.

    2008-03-01

    We conducted a 3-year artificial deepening of the thermocline in the dimictic Lake Breisjøen, southern Norway, by means of a large submerged propeller. An adjacent lake served as untreated reference. The manipulation increased thermocline depth from 6 to 20 m, caused a significant increase in the heat content, and delayed ice-on by about 20 days. There were only minor changes in water chemistry. Concentrations of sulphate declined, perhaps due to greater reduction of sulphate at the sediment-water interface. Concentrations of particulate carbon and nitrogen decreased, perhaps due to increased sedimentation velocity. Water transparency increased. There was no significant change in concentration of phosphorus, the growth-limiting nutrient. There were few significant changes in principal biological components. Phytoplankton biomass and productivity did not change, although the chlorophyll-a concentration showed a small decrease. Phytoplankton species richness increased, and the species composition shifted. Growth of periphyton increased. There was no change in the macrophyte community. The manipulation did not affect the zooplankton biodiversity, but caused a significant shift in the relative abundance (measured as biomass) in the two major copepod species. The manipulation did not affect the individual density, but appeared to have changed the vertical distribution of zoobenthos. Fish populations were not affected. The lake is oligotrophic and clearwater and the manipulation did not change the supply of phosphorus, and thus there were only minor changes in lake chemistry and biology. Effects might be larger in eutrophic and dystrophic lakes in which internal processes are stronger.

  1. Limnology of southern African coastal lakes — new vistas from ...

    Fourteen mostly small, isolated, and relatively deep coastal inundation lakes were surveyed during the cool season (August) of 1996. No thermal or chemical stratification existed, but near-bottom hypoxia was evident in several systems. Ionic conductivity varied quite widely, but was highest in isolated systems, suggesting ...

  2. Field responses of Prunus serotina and Asclepias syriaca to ozone around southern Lake Michigan

    Bennett, J.P. [U.S. Geological Survey and Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706 (United States)]. E-mail: jpbennet@wisc.edu; Jepsen, E.A. [Bureau of Air Management, Wisconsin Department of Natural Resources, Madison, WI 53707 (United States); Roth, J.A. [Bureau of Air Management, Wisconsin Department of Natural Resources, Madison, WI 53707 (United States)

    2006-07-15

    Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch elongation and milkweed growth and pod formation were significantly higher west of Lake Michigan while ozone injury was greater east of Lake Michigan. Using classification and regression tree (CART) analyses we determined that departures from normal precipitation, soil nitrogen and ozone exposure/peak hourly concentrations were the most important variables affecting cherry branch elongation, and milkweed stem height and pod formation. The effects of ozone were not consistently comparable with the effects of soil nutrients, weather, insect or disease injury, and depended on species. Ozone SUM06 exposures greater than 13 ppm-h decreased cherry branch elongation 18%; peak 1-h exposures greater than 93 ppb reduced milkweed stem height 13%; and peak 1-h concentrations greater than 98 ppb reduced pod formation 11% in milkweed. - Decreased cherry branch elongation, milkweed stem height and pod production, and foliar injury on both species occurred at sites around southern Lake Michigan at ozone exposures of 13 SUM06 ppm-h and 93-98 ppb peak hourly.

  3. Field responses of Prunus serotina and Asclepias syriaca to ozone around southern Lake Michigan

    Bennett, J.P.; Jepsen, E.A.; Roth, J.A.

    2006-01-01

    Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch elongation and milkweed growth and pod formation were significantly higher west of Lake Michigan while ozone injury was greater east of Lake Michigan. Using classification and regression tree (CART) analyses we determined that departures from normal precipitation, soil nitrogen and ozone exposure/peak hourly concentrations were the most important variables affecting cherry branch elongation, and milkweed stem height and pod formation. The effects of ozone were not consistently comparable with the effects of soil nutrients, weather, insect or disease injury, and depended on species. Ozone SUM06 exposures greater than 13 ppm-h decreased cherry branch elongation 18%; peak 1-h exposures greater than 93 ppb reduced milkweed stem height 13%; and peak 1-h concentrations greater than 98 ppb reduced pod formation 11% in milkweed. - Decreased cherry branch elongation, milkweed stem height and pod production, and foliar injury on both species occurred at sites around southern Lake Michigan at ozone exposures of 13 SUM06 ppm-h and 93-98 ppb peak hourly

  4. The offshore fish community in southern Lake Ontario, 1972-1998

    Owens, Randall W.; O'Gorman, Robert; Eckert, Thomas H.; Lantry, Brian F.; Munawar, M.

    2003-01-01

    The authors document the status of Lake Ontario's open-water fish community in 1972, near the beginning of an era of massive fish stocking and when phosphorus levels in the lake from anthropogenic inputs, were near their peak. They then describe changes that occurred in the fish community in 1978-98. This was a period when large numbers of young salmonid piscivores were released annually, sea lamprey control continued to improve, and phosphorus levels were declining due to successful nutrient abatement programs. Coincident with the above, the lower food web was changed by the addition of new exotic invertebrates, the zooplankter Bythotrephes cederstroemi and particularly the zebra mussel, Dreissena polymorpha, and quagga mussel, D. bugensis. The picture of the fish community structure is drawn from records of catches in bottom trawls and gill nets during surveys of southern Lake Ontario conducted the the U.S. Geological Survey (USGS) and the New York Department of Environmental Conservation (NYDEC), from records of fish stocked in Lake Ontario by the NYDEC, and from a creel census of boat anglers returning to southern Lake Ontario ports conducted by the NYDEC.

  5. A radioanalytical study of radionuclides in a dysoligotrophic lake in Southern Sweden

    Eriksson, M; Roos, P; Holm, E [Lund University Hospital, Lund, (Sweden). The Jubileum Institute, Department of Radiation Physics; Peck, G [University of Melbourne, Parkville, VIC (Australia). School of Physics, Marine Chemistry Laboratory

    1998-07-01

    Unusually high activity concentration of various artificial radionuclides (from nuclear test fallout and the Chernobyl accident) and some natural radionuclides, have been discovered in lakes with high amounts of humic substances. These lakes tend to have low pH, at times down to pH 5. The lake, Svartsjoen, in the southern part of Sweden is one of these lakes. The food chain and resulting concentration factors in Svartsjoen were investigated and compared to results for other 'normal' lakes. Fish and water samples were collected and analysed for {sup 137}Cs {sup 239+240}Pu, {sup 241}Am and {sup 210}Po during a 4-month visit to Lund. The level of {sup 239/240}Pu in the water of Svartsjoen was found to be elevated. The work on fish from the lake indicates that these elevated levels are not transferred into the food chain. It appears that the humic substances could be blocking plutonium from entering the food chain.

  6. Mercury concentrations of fish in Southern Indian Lake and Issett Lake, Manitoba 1975-88: The effect of lake impoundment and Churchill River diversion

    Strange, N.E.; Bodaly, R.A.; Fudge, R.J.P.

    1991-01-01

    Southern Indian and Issett Lakes in northern Manitoba were flooded in 1976 as part of Manitoba Hydro's Churchill River diversion project. Fish were collected from 1975 to 1988 from five regional sites on the lakes to examine the effects of impoundment and river diversion on muscle mercury concentrations. Raw data for individual fish caught in 1987 and 1988 are presented, along with means and analyses calculated over the entire 1975-1988 study period. Mercury concentrations in whitefish, pike, and walleye increased significantly after impoundment. Whitefish mercury levels peaked in 1978 and have since declined to near pre-flooding levels. Northern pike and walleye mercury levels were much higher than for whitefish. Pike mercury concentrations showed no indication of declining after 12 years of impoundment, but walleye mercury levels at 2 of the 5 Southern Indian Lake sites declined from maximum recorded levels. Significant variability in fish mercury concentrations was noted both from year to year and among the sites. It is suggested that site-to-site variations are due to varying conditions in the reservoir which stimulate mercury methylation. Since there appears to be an ongoing long-term source of mercury and organic material from the eroding shorelines, pike and walleye mercury concentrations are expected to remain high for many years. 25 refs., 7 figs., 20 tabs

  7. Alcohol consumption and risky sexual behaviour in the fishing communities: evidence from two fish landing sites on Lake Victoria in Uganda.

    Tumwesigye, Nazarius M; Atuyambe, Lynn; Wanyenze, Rhoda K; Kibira, Simon Ps; Li, Qing; Wabwire-Mangen, Fred; Wagner, Glenn

    2012-12-11

    The fishing communities are among population groups that are most at risk of HIV infection, with some studies putting the HIV prevalence at 5 to 10 times higher than in the general population. Alcohol consumption has been identified as one of the major drivers of the sexual risk behaviour in the fishing communities. This paper investigates the relationship between alcohol consumption patterns and risky behaviour in two fishing communities on Lake Victoria. Face-to-face interviews were conducted among 303 men and 172 women at the fish landing sites; categorised into fishermen, traders of fish or fish products and other merchandise, and service providers such as casual labourers and waitresses in bars and hotels, including 12 female sexual workers. Stratified random sampling methodology was used to select study units. Multivariable analysis was conducted to assess independent relationship between alcohol consumption and sexual risky behaviour. Measures of alcohol consumption included the alcohol use disorder test score (AUDIT), having gotten drunk in previous 30 days, drinking at least 2 times a week while measures for risky behaviour included engaging in transactional sex, inconsistent condom use, having sex with non-regular partner and having multiple sexual partners. The level of harmful use of alcohol in the two fishing communities was quite high as 62% of the male and 52% of the female drinkers had got drunk in previous 30 days. The level of risky sexual behaviour was equally high as 63% of the men and 59% of the women had unprotected sex at last sexual event. Of the 3 occupations fishermen had the highest levels of harmful use of alcohol and risky sexual behaviour followed by service providers judging from values of most indicators. The kind of alcohol consumption variables correlated with risky sexual behaviour variables, varied by occupation. Frequent alcohol consumption, higher AUDIT score, having got drunk, longer drinking hours and drinking any day of

  8. Alcohol consumption and risky sexual behaviour in the fishing communities: evidence from two fish landing sites on Lake Victoria in Uganda

    Tumwesigye Nazarius M

    2012-12-01

    Full Text Available Abstract Background The fishing communities are among population groups that are most at risk of HIV infection, with some studies putting the HIV prevalence at 5 to 10 times higher than in the general population. Alcohol consumption has been identified as one of the major drivers of the sexual risk behaviour in the fishing communities. This paper investigates the relationship between alcohol consumption patterns and risky behaviour in two fishing communities on Lake Victoria. Methods Face-to-face interviews were conducted among 303 men and 172 women at the fish landing sites; categorised into fishermen, traders of fish or fish products and other merchandise, and service providers such as casual labourers and waitresses in bars and hotels, including 12 female sexual workers. Stratified random sampling methodology was used to select study units. Multivariable analysis was conducted to assess independent relationship between alcohol consumption and sexual risky behaviour. Measures of alcohol consumption included the alcohol use disorder test score (AUDIT, having gotten drunk in previous 30 days, drinking at least 2 times a week while measures for risky behaviour included engaging in transactional sex, inconsistent condom use, having sex with non-regular partner and having multiple sexual partners. Results The level of harmful use of alcohol in the two fishing communities was quite high as 62% of the male and 52% of the female drinkers had got drunk in previous 30 days. The level of risky sexual behaviour was equally high as 63% of the men and 59% of the women had unprotected sex at last sexual event. Of the 3 occupations fishermen had the highest levels of harmful use of alcohol and risky sexual behaviour followed by service providers judging from values of most indicators. The kind of alcohol consumption variables correlated with risky sexual behaviour variables, varied by occupation. Frequent alcohol consumption, higher AUDIT score, having

  9. Macrobenthic fauna community in the Middle Songkhla Lake, Southern Thailand

    Angsupanich, S.

    2005-02-01

    Full Text Available A bimonthly investigation of macrobenthic fauna at the area from Ban Pak Khat to Ban Leam Chong Thanon in the Inner Songkhla Lake from February 1998 to February 1999 was undertaken to determine the species richness and abundance. A total of 7 phyla and 161 species were identified. Annelida (58 species, Arthropoda (64 species and Mollusca (23 species were the major phyla while Nemertea (1 species, Platyhelminthes (1 species, Cnidaria (4 species and Chordata (10 species were the minor. Fifty-seven speciesof Polychaete annelids were found. The highest species richness (14 species was in the Nereididae Family, of which Ceratonereis burmensis and Namalycastis indica were predominant. Nephtys sp. and Heteromastus sp. were not so highly abundant but appeared at almost all stations through every sampling month, while Prionospio cirrifera and Pseudopolydora kempi were found in higher densities but with narrower distribution. Ficopomatus sp. and unidentified Terebellidae were not commonly found, but occasionally reached a high density. Amphipods gave the highest species richness (22 species, with Photis longicaudata distributed widely and in all months. Five species of Tanaidaceans were found with Apseudes sapensis the second most dominant (max. 5044 individuals m-2 in February in the overall fauna. Isopoda were not as densely found as tanaidaceans but there were many species (18 species. Cyathura sp.1 was the most dominant isopod. Brachidontes arcuatulus was the most dominant bivalve (max. 29449 individuals m-2 in April, especially at stations with a sand-gravel substrate. The mean density of total macrobenthic fauna among stations ranged from 920 to 10620 ind. m-2 while the monthly densities ranged from 1520 to 6160 ind.m-2. The mean density of macrobenthic fauna was highest in the dry season (April. The species richness among stations ranged from65 to 105 species while varying from 81 to 112 species during the different months. The highest species

  10. The paleolimnological development of the twin lakes Etujärvi and Takajärvi in Askola, southern Finland – implications for lake management

    Samu E. Valpola

    2006-01-01

    Full Text Available The twin lakes Etujärvi and Takajärvi in Askola, southern Finland, are closely interconnected mesotrophic headwater lakes with a relatively small catchment area. Both of the lakes have suffered from eutrophication and its consequences. Remediation activities such as oxygenation and biomanipulation have not resolved the problems. In this study a large set of paleolimnological techniques (radiometric AMS dating, spherical carbonaceous particles analysis, sediment lithology, grain-size analysis, phosphorus fractionation, and diatom analysis were applied to put together the development of the basin and its water level fluctuations during the Holocene. The age for observed Trapa natans -horizons was determined, and lake management options were discussed. The studied lakes dried up after isolation from the Ancylus Lake at about 9500 cal. B.P. and remained at very low water level until ca. 8700–8500 cal. B.P. The mid-Holocene risein water level resulted in fluctuating water levels, and led to the most recent rise starting about 2500 cal. B.P. as wet and cool climate conditions prevailed. The pronounced water level fluctuations led to the extensive growth of peat deposits surrounding the lake andprobably also forced T. natans to disappear from lake flora. The unstable, erodable peat rims impact the lakes, causing heavy load of humic substances to the lake and presenting additional deterioration to their recreational value.

  11. Antarctic lakes suggest millennial reorganizations of Southern Hemisphere atmospheric and oceanic circulation.

    Hall, Brenda L; Denton, George H; Fountain, Andrew G; Hendy, Chris H; Henderson, Gideon M

    2010-12-14

    The phasing of millennial-scale oscillations in Antarctica relative to those elsewhere in the world is important for discriminating among models for abrupt climate change, particularly those involving the Southern Ocean. However, records of millennial-scale variability from Antarctica dating to the last glacial maximum are rare and rely heavily on data from widely spaced ice cores, some of which show little variability through that time. Here, we present new data from closed-basin lakes in the Dry Valleys region of East Antarctica that show high-magnitude, high-frequency oscillations in surface level during the late Pleistocene synchronous with climate fluctuations elsewhere in the Southern Hemisphere. These data suggest a coherent Southern Hemisphere pattern of climate change on millennial time scales, at least in the Pacific sector, and indicate that any hypothesis concerning the origin of these events must account for synchronous changes in both high and temperate latitudes.

  12. Modeling detection probability to improve marsh bird surveys in southern Canada and the Great Lakes states

    Douglas C. Tozer

    2016-12-01

    Full Text Available Marsh birds are notoriously elusive, with variation in detection probability across species, regions, seasons, and different times of day and weather. Therefore, it is important to develop regional field survey protocols that maximize detections, but that also produce data for estimating and analytically adjusting for remaining differences in detections. We aimed to improve regional field survey protocols by estimating detection probability of eight elusive marsh bird species throughout two regions that have ongoing marsh bird monitoring programs: the southern Canadian Prairies (Prairie region and the southern portion of the Great Lakes basin and parts of southern Québec (Great Lakes-St. Lawrence region. We accomplished our goal using generalized binomial N-mixture models and data from ~22,300 marsh bird surveys conducted between 2008 and 2014 by Bird Studies Canada's Prairie, Great Lakes, and Québec Marsh Monitoring Programs. Across all species, on average, detection probability was highest in the Great Lakes-St. Lawrence region from the beginning of May until mid-June, and then fell throughout the remainder of the season until the end of June; was lowest in the Prairie region in mid-May and then increased throughout the remainder of the season until the end of June; was highest during darkness compared with light; and did not vary significantly according to temperature (range: 0-30°C, cloud cover (0%-100%, or wind (0-20 kph, or during morning versus evening. We used our results to formulate improved marsh bird survey protocols for each region. Our analysis and recommendations are useful and contribute to conservation of wetland birds at various scales from local single-species studies to the continental North American Marsh Bird Monitoring Program.

  13. Fish communities of the Wilderness Lakes System in the southern Cape, South Africa

    Alexis A. Olds

    2016-08-01

    Full Text Available The Wilderness Lakes System, a temporarily open and closed estuary with three associated lakes situated in the southern Cape region of South Africa, was sampled using a range of sampling gears to assess the fish community. A total of 25 species were sampled throughout the system, with the highest diversity in the Touw Estuary (23 species and the lowest in Langvlei (11 species. Estuary-associated marine species (13 species dominated species richness with smaller proportions of estuarine resident (7 species, freshwater (3 species and catadromous species (2 species. Estuarine resident species dominated the catch numerically. The size–class distribution of euryhaline marine species indicated that upon entering the Touw Estuary as juveniles, the fish move up the system towards Rondevlei where they appear to remain. Three freshwater species were recorded in the system, all of which are alien to the Wilderness Lakes System. Decreasing salinity in the upper lakes appears to be a driving factor in the distribution and increasing abundance of the freshwater fishes. Sampling followed a drought, with the system experiencing substantially increased levels of mouth closure compared to a similar study conducted in the 1980s. The timing of mouth opening and the degree of connectivity between the lakes influence the nursery function of the system as a whole. Management actions need to focus on improving ecological functioning of this system, in particular how mouth opening is managed, to facilitate nursery function and limit the establishment of invasive species. Conservation implications: Key management actions are required to improve fish recruitment potential into and within the system. These include maintenance of adequate marine inflow through adherence to artificial mouth breaching protocols and improving connectivity between the lakes through sediment removal from localised deposition points within the connecting channels.

  14. Field responses of Prunus serotina and Asclepias syriaca to ozone around southern Lake Michigan.

    Bennett, J P; Jepsen, E A; Roth, J A

    2006-07-01

    Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch elongation and milkweed growth and pod formation were significantly higher west of Lake Michigan while ozone injury was greater east of Lake Michigan. Using classification and regression tree (CART) analyses we determined that departures from normal precipitation, soil nitrogen and ozone exposure/peak hourly concentrations were the most important variables affecting cherry branch elongation, and milkweed stem height and pod formation. The effects of ozone were not consistently comparable with the effects of soil nutrients, weather, insect or disease injury, and depended on species. Ozone SUM06 exposures greater than 13 ppm-h decreased cherry branch elongation 18%; peak 1-h exposures greater than 93 ppb reduced milkweed stem height 13%; and peak 1-h concentrations greater than 98 ppb reduced pod formation 11% in milkweed.

  15. Sedimentary record of heavy metals in Lake Rõuge Liinjärv, southern Estonia

    Lepane, Viia

    2007-12-01

    Full Text Available Anthropogenic impact on Lake Liinjärv (Rõuge, southern Estonia was studied back to the mid-19th century on the basis of heavy metals (Pb, Cu, Zn, Mn, and Hg and geochemical parameters of a short sediment core dated by 210Pb isotopes. The development of the lake and its sediment composition are heavily influenced by the inflow of saturated calcareous waters that cause precipitation of calcium carbonates. The concentrations of most of the metals started to increase at the end of the 1970s. This is most clearly observable for Zn, Cu, and Pb. At the same time the distribution pattern of Mn seems to be controlled mainly by the redox conditions in the hypolimneon. The main sources of pollutants in Lake Liinjärv, due to its large catchment area, are the influence of agricultural activity and atmospheric input. Organic matter is the main factor affecting heavy metal (Pb, Hg, Cu, and Zn distribution in lake sediments.

  16. Stable lead geochronology of fine-grained sediments in Southern Lake Michigan

    Robbins, J.A.; Edgington, D.N.

    1974-01-01

    In a previous article, it was shown that the vertical distribution of stable lead in the fine-grained sediments of Lake Michigan reflects the history of cultural lead inputs. It was found that the lead distributions in dated cores are quantitatively described by a universal time-dependent loading or source function which is a linear combination of estimated annual inputs of atmospheric lead derived from the combustion of leaded gasoline and the burning of coal in and around Chicago since about 1800. The existence of such a source function for lead implies that stable lead itself may be used to date sediment cores. Mercury depth profiles in western Lake Erie sediments have shown several horizons which correspond to the development of local industrial use of mercury over the past forty years or so. The construction of the lead source function for Lake Michigan sediments was based on only four lead-210 dated cores. To establish the validity of the source function concept, it is applied to the distribution of lead determined in many cores previously obtained from southern Lake Michigan

  17. LATE GLACIAL AND HOLOCENE BIOCLIMATIC RECONSTRUCTION IN SOUTHERN ITALY: THE TRIFOGLIETTI LAKE

    E. Brugiapaglia

    2013-04-01

    Full Text Available The pollen record from Trifoglietti lake (Calabria region provides new information about the paleoenvironmental and palaeoclimatic changes occurred during the LateGlacial and Holocene period. The LateGlacial part of the record, for which only preliminary data is available, is a new and original sequence from southern Italy. The Holocene sequence, with 11 AMS radiocarbon dates shows a stable Fagus forest for the entire period. Apart from sporadic pastoralism activities and the selective exploitation of Abies, only a weak human impact is recognized in the pollen records. Lake level oscillations have been reconstructed and annual precipitations quantified using the Modern Analogue Technique. The reconstruction was effectuated both at millennial and centennial scale: the first shows an increasing of moisture from 11000 to 9400 cal BP and a maximum of humidity from 9400 to 6200 cal BP. Moreover, several climatic oscillations punctuated the Holocene and therefore superimposed the millennial trend.

  18. Mercury in Some Lakes of Gold Mining Area of the Southern Ural

    Tatsy Y. G.

    2013-04-01

    Full Text Available The mercury content in bottom sediments of Kalkan Lake, of the Uchala district, the Southern Ural. It was assumed that high concentrations of mercury in fish due to pollution of bottom sediments as a result of amalgamation at developing of gold placers. Detailed study of distribution of different elements in sediments show close association Hg with the chalcophylic elements, whose anomalies do not have technogenic nature. Association of mercury with the elements-companions of gold placers is evidence of basic contribution of natural mercury to its anomalous accumulation in sediments and fish. This is result of steady long-term natural mercury pollution.

  19. Radiological effects of Chernobyl reactor accident on the lakes of Southern Bavaria

    Laschka, D.; Hermann, H.; Huebel, K.; Luensmann, W.

    1988-03-01

    In order to detect the radiological effects of the Chernobyl reactor accident to the large lakes of Southern Bavaria and to assess the radiation exposure of man on the different aquatic pathways, the radioactive contamination of the surface water, the sediments and the fishes was investigated. The dependence of time of the activity concentrations in the tested medias is shown and an outlook is made on the expected further evolution. The radiation exposure of man by swimming, boating and fish consumption in the fast year after the reactor accident is calculated [fr

  20. New Progress on Radiocarbon Geochronology in Southern Lake Tanganyika (East Africa)

    McGlue, M. M.; Soreghan, M. J.

    2017-12-01

    Our limnogeological research in Lake Tanganyika focuses on elucidating the patterns of sediment accumulation on deepwater horsts, outer platforms, and littoral environments in the lake's southern basin ( 6-8°S latitude). Here, we present new radiocarbon (14C) dates from high-quality surface sediment cores, in order to make comparisons with previously published age models, to address the presence and spatiotemporal variability of a reservoir effect, and to constrain sedimentation rates and facies at sites that may be important targets for future scientific drilling. Plant macrofossils are rare in deepwater sediment cores, so charcoal and bulk organic matter have been the primary materials used for dating. On the Kavala Island Ridge (KIR) horst, initial core descriptions revealed variations in laminae presence, thickness, and chemistry. Sediment cores from the KIR at 172m water depth consist of thickly laminated diatom oozes. Charcoal from the bases of these cores returned median ages of 2.1-2.2 cal ka, suggesting linear accumulation rates on the order of 0.51 mm/yr. By contrast, a core from 420 m water depth on the KIR exhibited very thin laminations and diatom layers were much less prominent. Charcoal at the base of this core produced a median age of 8.1 cal ka, suggesting a linear accumulation rate of 0.11 mm/yr. These initial results suggest that sedimentation rates may vary considerably over sublacustrine horst blocks. We will test this initial discovery with additional sedimentation rate information from the Kalya and Nitiri horsts. In addition, we report new 14C dates made on both dead and live-collected shells of the endemic gastropod Neothauma tanganyicense. These shells form vast accumulations along shallow-water platforms of the lake and form an important substrate for a number of other endemic species. The discovery of living snails in southern Lake Tanganyika may allow for the development of a species-specific reservoir correction. A limited N

  1. The upper lithostratigraphic unit of ANDRILL AND-2A core (Southern McMurdo Sound, Antarctica): local Pleistocene volcanic sources, paleoenvironmental implications and subsidence in the southern Victoria Land Basin

    Del Carlo, P.; Panter, K. S.; Bassett, K. N.; Bracciali, L.; di Vincenzo, G.; Rocchi, S.

    2009-12-01

    We report results from the study of the uppermost 37 meters of the Southern McMurdo Sound (SMS) AND-2A drillcore, corresponding to the lithostratigraphic unit 1 (LSU 1), the most volcanogenic unit within the core. Nearly all of LSU 1 consists of volcanic breccia and sandstone that is a mixture of near primary volcanic material dominated by lava and vitric clasts with minor exotic material derived from distal basement sources. Lava clasts and glass are mafic and range from strongly alkaline (basanite, tephrite) to moderately alkaline (alkali basalt, hawaiite) compositions that are similar to nearby land deposits. 40Ar-39Ar laser step-heating analyses on groundmass separated from lava clasts yield Pleistocene ages (692±38 and 793±63, ±2σ internal errors). Volcanoes of the Dailey Island group, located ~13 km SW of the drillsite, are a possible source for the volcanic materials based on their close proximity, similar composition and age. A basanite lava flow on Juergens Island yields a comparable Pleistocene age of 775±22 ka. Yet there is evidence to suggest that the volcanic source is much closer to the drillsite and that the sediments were deposited in much shallower water relative to the present-day water depth of 384 mbsl. Evidence for local volcanic activity is based in part on the common occurrence of delicate vitriclasts (e.g. glass shards and Pele’s hair) and a minimally reworked ~2 meter thick monomict breccia that is interpreted to have formed by autobrecciating lava. In addition, conical-shaped seamounts and high frequency magnetic anomalies encompass the drillsite and extend south including the volcanoes of the Dailey Islands. Sedimentary features and structures indicate shallow water sedimentation for the whole of LSU 1. Rippled asymmetric cross-laminated sands and hummocky cross-stratification occur intermittently throughout LSU 1 and indicate water depths shallower than 100 meters. The occurrence of ooliths and layers containing siderite and Fe

  2. Invasive Ponto-Caspian hydrozoan Cordylophora caspia (hydrozoa: Cnidaria) in southern Baltic coastal lakes

    Obolewski, Krystian; Jarosiewicz, Anna; Ożgo, Małgorzata

    2015-12-01

    Cordylophora caspia Pall. is a highly invasive Ponto-Caspian colonial hydroid with a worldwide distribution. It is a biofouling organism colonizing industrial water installations and causing serious economic problems. Here, we give the first report of its occurrence in southern Baltic coastal lakes, and analyze its distribution in relation to environmental factors and likely colonization routes. Samples were collected from the stalks of Phragmites australis at the total of 102 sites in 15 lakes and lagoons. The species was most numerous in lagoons, i.e. ß-oligohaline water bodies with a surface hydrological connection with the sea, where it reached mean densities of 1200-4800 hydranths m-2. In regression tree analysis, chloride concentration, followed by pH, were the strongest explanatory variables for its occurrence, with highest densities observed at chloride concentration above 1.18 g Cl L-1 and pH 8.05-9.26. At pH 5.77-8.04 higher densities were observed at temperatures above 20.3 °C. Generally, within the range of parameters observed in our study, high densities of C. caspia were associated with high chloride concentration, pH, temperature and electrical conductivity values. The species was also present in freshwater lakes; these colonies may have the highest capacity for future invasions of such habitats. Within lakes, high densities were observed at canals connecting these water bodies with the sea, and at sites close to the inflow of rivers. This distribution pattern can facilitate its further spread into inland waters.

  3. Lake Morphometry for NHD Lakes in the Southern Portion of the South Atlantic-Gulf Region 3 HUC

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  4. THE QUALITY OF WATER AND ICHTHIOFAUNA OF THE SOUTHERN LAKE IN OSIJEK – THE CONDITIONS FOR BIOMANIPULATION

    Melita Mihaljević

    1996-09-01

    Full Text Available The Southern lake is shallow (deep up to 4 meters artificial lake with the ackerage of 6. 25. It is situated within the city of Osijek. Its reconstruction began in 1995, after it has been polluted for many years. The results of, hydrobiological examination show the basic ecological characteristics of the Southern lake: high transparency, great quantity of nutrients and highly developed macrophit vegetation. After the conducted analysis of the qualitative composition of the ichthiofauna, it has been found that the lake has 13 species of fish form six families, with the greatest number of them coming from Cyprinidae family. idae family. The fish species that outnumbers all other in the quantitative composition of the ichtiofauna is P. parua, but also well represented are L. gibosus, C. carrasius gibelio, Scardinius erythrophthalmus and Rutilus rutilus. In the trophic structure, the ratio of the predatory species is disadvantageous in relation to the unpredatory species. The application of the biomanipulation method has been suggested for the further reconstruction of the Southern lake: the quantity of the macrophit vegetation should be reduced by the way of its direct removal and the input of the herbivore fish species. The disadvantageous trophic ratio should be changed by overfishing of predatory species within the ichthiofauna and the input of unpredatory fish species.

  5. A pollen-based record of late glacial-Holocene climatic variability in the southern lake district, Chile

    Vargas-Ramirez, L.; Roche, E.; Gerrienne, P.; Hooghiemstra, H.

    2008-01-01

    A pollen record from Puyehue area (40°S; 72°W) in the southern Lake District, Chile, indicates that prior to 13,410 14C yr BP (ca. 16,500-15,200 cal yr BP), cold resistant and hygrophilous vegetation, particularly Nothofagus forest and myricaceous vegetation, covered the area. From ca. 15,000 cal yr

  6. Sedimentological and mineralogical characteristics of recent sediments at selected sites in the southern basin of Lake Michigan

    Tisue, G.T.; Merk, G.

    1976-01-01

    During the 1976 field season, sediment traps and current meters were set out in the southern basin of Lake Michigan to study the relationship between suspended material and currents. The gross mineralogical and chemical characteristics of the bottom sediments at the locations of these experiments were determined

  7. Knowledge, attitude, and practices on intestinal schistosomiasis among primary schoolchildren in the Lake Victoria basin, Rorya District, north-western Tanzania

    David Z. Munisi

    2017-09-01

    Full Text Available Abstract Background Globally school-age children, adolescents and young adults bear the highest burden of schistosomiasis. When developing a specific intervention to improve community’s knowledge, attitudes, and practices (KAPs, existing KAPs must be taken into account. Therefore, this study was designed to determine schoolchildren’s KAPs on schistosomiasis in the study area. Methods A cross-sectional study was conducted in Busanga and Kibuyi villages involving 513 schoolchildren. A pre-tested questionnaire was used to collect socio-demographic data and to assess KAP on schistosomiasis among primary schoolchildren in the study area. Results Of the 488 interviewed children, 391 (80.12% reported to have heard of schistosomiasis, with the majority 289 (73.91% citing school as the source of this knowledge. Swimming in the lake, worms, witchcraft, and mosquitoes were mentioned to be the cause for intestinal schistosomiasis. Fishing in the lake, drinking unboiled lake water, walking bare footed, and shaking hands were reported to be practices that may lead to contracting schistosomiasis. Only 156 (39.90% of the study respondents reported to know the signs of intestinal schistosomiasis. Avoiding swimming in the lake, drinking unboiled water and eating unwashed fruits were mentioned as preventive measures. Nearly 85% (412 reported understanding that there was a disease known as schistosomiasis; additionally, 419 (85.86% considered schistosomiasis as a dangerous disease and 418 (85.66% believed that schistosomiasis was treatable. Fishermen and schoolchildren were reported to be groups most at risk of schistosomiasis infection. Visiting the lake (for swimming and other gatherings was a common practice among study participants 471 (96.52%.Nearly 93% (451 of participants mentioned using lake water for domestic chores, and, although 407 (84.61% reported to own a toilet at home, only 229 (55.31% reported to always use a toilet for sanitation purposes

  8. Biomagnification of mercury and selenium in two lakes in southern Norway

    Økelsrud, Asle, E-mail: asle.okelsrud@hit.no [Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, 3800 Bø (Norway); Lydersen, Espen [Department of Environmental and Health Studies, University College of Southeast Norway, Hallvard Eikas Plass 1, 3800 Bø (Norway); Fjeld, Eirik [Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo (Norway)

    2016-10-01

    We have investigated bioaccumulation and trophic transfer of both mercury (Hg) and selenium (Se) in two lakes in southern Norway to reveal a suggested mitigating effect of Se on Hg biota accumulation. The study included analysis of total Se (Se), total Hg (Hg), and methyl-mercury (MeHg) in water, littoral and pelagic invertebrates and perch (Perca fluviatilis), together with stable isotope analysis (δ{sup 15}N and δ{sup 13}C) in biota. Mean dissolved Se ranged from 22 to 59 ng L{sup −1}, while Hg and MeHg in lake water ranged from 1 to 3 ng L{sup −1} and 0.01 to 0.06 ng L{sup −1}. Biota Se and Hg concentrations (dry weight) ranged from 0.41 mg Se kg{sup −1} and 0.06 mg Hg kg{sup −1} in primary littoral invertebrates and up to 2.9 mg Se kg{sup −1} and 3.6 mg Hg kg{sup −1} in perch. Both Hg and Se biomagnified in the food web, with a trophic magnification factor (TMF) of 4.64 for Hg and 1.29 for Se. The reported positive transfer of Se in the food web, despite the low measured dissolved Se, suggest that a major proportion of the Se in these lakes are both highly bioavailable and bioaccumulative. However, we did not find support for a Se-facilitated inhibition in the accumulation of Hg in perch, as Se and Hg concentrations in perch muscle correlated positively and Se did not explain any variations in Hg after we controlled for the effects of other important covariates. We postulate that this may be a result of insufficient concentrations of dissolved Se and subsequently in biota in our studied lakes for an efficient Hg sequestration up the food web. - Highlights: • Hg, Se and stable isotopes were investigated in biota in two Norwegian Boreal lakes • Both Hg and Se biomagnified in the food web, with a TMF of 4.64 and 1.29 respectively • Food carbon source, trophic level and age explained Se and Hg variations in perch • Perch muscle Se and Hg were positively correlated.

  9. Long term behaviour and seasonal cycling of Cs-137 in a eutrophic lake in Southern Germany

    Klemt, E.; Knaus, J.; Putyrskaya, V.; Ries, T. [Hochschule Ravensburg-Weingarten (Germany)

    2014-07-01

    Lake Vorsee is a small and shallow eutrophic lake with a swampy watershed about 25 km north of Lake Constance in southern Germany which is intensely used for fishing by local fishermen. It is completely overgrown by watermilfoil (Myriophyllum spicatum) which produces thick watery organic sediment layers when it decomposes in late autumn and winter. In 1986 the watershed of Lake Vorsee had a Cs-137 Chernobyl inventory of about 30 kBq/m{sup 2}. The Cs-137 activity concentration in the water was monitored for more than 25 years and it can be well described by a sum of two exponential functions superimposed by some seasonal cycling. To analyze the seasonal cycling of the Cs-137 activity concentration in water and in suspended matter, samples were collected with a Large Volume Water Sampler (Midiya-System) on a monthly base and measured gamma-spectrometrically by HPGe-detectors. Also the Cs-137 distribution coefficient kD was determined. Additionally, in the lake water the concentration of the competing ions K{sup +} and NH{sub 4}{sup +} was determined by ion-chromatography, total organic carbon (TOC) with a combustion catalytic oxidation / NDIR detection method as well as the dissolved O{sub 2}-concentration and the pH and temperature of the water by hand-held probes. Information on the amount of precipitation was taken from nearby weather stations. In this project the following hypothesis will be checked: In late autumn the decomposing watermilfoil produces NH{sub 4}{sup +}-ions which exchange Cs{sup +}-ions from their binding places, thereby increasing the Cs-137 activity concentration in the water. In spring the watermilfoil starts growing which leads to a larger O{sub 2}-concentration in the water and helps to disintegrate the NH{sub 4}{sup +}-ions in this way decreasing the Cs-137 concentration again. A possible influence of the other measured parameters on the seasonal cycling will also be discussed. Document available in abstract form only. (authors)

  10. Biomagnification of mercury and selenium in two lakes in southern Norway

    Økelsrud, Asle; Lydersen, Espen; Fjeld, Eirik

    2016-01-01

    We have investigated bioaccumulation and trophic transfer of both mercury (Hg) and selenium (Se) in two lakes in southern Norway to reveal a suggested mitigating effect of Se on Hg biota accumulation. The study included analysis of total Se (Se), total Hg (Hg), and methyl-mercury (MeHg) in water, littoral and pelagic invertebrates and perch (Perca fluviatilis), together with stable isotope analysis (δ 15 N and δ 13 C) in biota. Mean dissolved Se ranged from 22 to 59 ng L −1 , while Hg and MeHg in lake water ranged from 1 to 3 ng L −1 and 0.01 to 0.06 ng L −1 . Biota Se and Hg concentrations (dry weight) ranged from 0.41 mg Se kg −1 and 0.06 mg Hg kg −1 in primary littoral invertebrates and up to 2.9 mg Se kg −1 and 3.6 mg Hg kg −1 in perch. Both Hg and Se biomagnified in the food web, with a trophic magnification factor (TMF) of 4.64 for Hg and 1.29 for Se. The reported positive transfer of Se in the food web, despite the low measured dissolved Se, suggest that a major proportion of the Se in these lakes are both highly bioavailable and bioaccumulative. However, we did not find support for a Se-facilitated inhibition in the accumulation of Hg in perch, as Se and Hg concentrations in perch muscle correlated positively and Se did not explain any variations in Hg after we controlled for the effects of other important covariates. We postulate that this may be a result of insufficient concentrations of dissolved Se and subsequently in biota in our studied lakes for an efficient Hg sequestration up the food web. - Highlights: • Hg, Se and stable isotopes were investigated in biota in two Norwegian Boreal lakes • Both Hg and Se biomagnified in the food web, with a TMF of 4.64 and 1.29 respectively • Food carbon source, trophic level and age explained Se and Hg variations in perch • Perch muscle Se and Hg were positively correlated

  11. Integrated Remote Sensing and Geophysical Investigations of the Geodynamic Activities at Lake Magadi, Southern Kenyan Rift

    Akinola Adesuji Komolafe

    2012-01-01

    Full Text Available The tectonic lineaments and thermal structure of Lake Magadi, southern Kenyan rift system, were investigated using ASTER data and geophysical methods. Five N-S faults close to known hot springs were identified for geoelectric ground investigation. Aeromagnetic data were employed to further probe faults at greater depths and determine the Curie-point depth. Results indicate a funnel-shaped fluid-filled (mostly saline hydrothermal zone with relatively low resistivity values of less than 1 Ω-m, separated by resistive structures to the west and east, to a depth of 75 m along the resistivity profiles. There was evidence of saline hydrothermal fluid flow toward the surface through the fault splays. The observed faults extend from the surface to a depth of 7.5 km and are probably the ones that bound the graben laterally. They serve as major conduits for the upward heat flux in the study area. The aeromagnetics spectral analysis also revealed heat source emplacement at a depth of about 12 km. The relative shallowness implies a high geothermal gradient evidenced in the surface manifestations of hot springs along the lake margins. Correlation of the heat source with the hypocenters showed that the seismogenetic zone exists directly above the magmatic intrusion, forming the commencement of geodynamic activities.

  12. First evidence of microplastics in the African Great Lakes

    Biginagwa, Fares John; Mayoma, Bahati Sosthenes; Shashoua, Yvonne

    2016-01-01

    -FTIR) spectroscopy. A variety of polymer types were identified with likely sources being urban waste and consumer use. Although further research is required to fully assess the impact of plastic pollution in this region, our study is the first to report the presence of microplastics in Africa's Great Lakes...... on the southern shore of Lake Victoria. The gastrointestinal tracts of locally fished Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) were examined for plastics. Plastics were confirmed in 20% of fish from each species by Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  13. Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America

    I. Levy

    2010-11-01

    Full Text Available This study examines the complexity of various processes influencing summertime ozone levels in the southern Great Lakes region of North America. Results from the Border Air Quality and Meteorology (BAQS-Met field campaign in the summer of 2007 are examined with respect to land-lake differences and local meteorology using a large array of ground-based measurements, aircraft data, and simulation results from a high resolution (2.5 km regional air-quality model, AURAMS.

    Analyses of average ozone mixing ratio from the entire BAQS-Met intensive campaign period support previous findings that ozone levels are higher over the southern Great Lakes than over the adjacent land. However, there is great heterogeneity in the spatial distribution of surface ozone over the lakes, particularly over Lake Erie during the day, with higher levels located over the southwestern end of the lake. Model results suggest that some of these increased ozone levels are due to local emission sources in large nearby urban centers. While an ozone reservoir layer is predicted by the AURAMS model over Lake Erie at night, the land-lake differences in ozone mixing ratios are most pronounced during the night in a shallow inversion layer of about 200 m above the surface. After sunrise, these differences have a limited effect on the total mass of ozone over the lakes and land during the day, though they do cause elevated ozone levels in the lake-breeze air in some locations.

    The model also predicts a mean vertical circulation during the day with an updraft over Detroit-Windsor and downdraft over Lake St. Clair, which transports ozone up to 1500 m above ground and results in high ozone over the lake.

    Oscillations in ground-level ozone mixing ratios were observed on several nights and at several ground monitoring sites, with amplitudes of up to 40 ppbv and time periods of 15–40 min. Several possible mechanisms for these oscillations are discussed, but a

  14. Cs-137 in aquatic organisms in the southern Lake Keurusselkae (Finland)[Radioecology

    Ilus, E.; Klemola, S.; Vartti, V.P.; Mattila, J.; Ikaeheimonen, T.K. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2006-04-15

    The results of a study carried out in Lake Keurusselkae, in the Finnish Lake District, are reported. The aim of the study was to collect biota samples for the INDOFERN Project from an area that was rather highly contaminated (70 kBq m{sup -2} of {sup 137}Cs in 1986) with the Chernobyl fallout in Finland. The samples were taken from a relatively small area surrounding the island of Iso Riihisaari in the southern part of the Keurusselkae water course. In total 15 samples of aquatic plants, 6 samples of aquatic animals, 1 water sample and 2 sediment cores were taken. In August 2003, the activity concentration of {sup 137}Cs in the surface water of the southern Lake Keurusselkae was 49 Bq m{sup -3}, whereas it was 310 Bq m{sup -3} in 1988, two year after the Chernobyl accident. In the relatively shallow area surrounding the island of Iso Riihisaari, the total amount of {sup 137}Cs in sediments was 32-37 kBq m{sup -2} in 2003, but in a deeper basin close to this area the total amount of {sup 137}Cs was 130 kBq m{sup -2} in 1990. The clearly highest activity concentration and concentration factor of {sup 137}Cs was found in one sample of Water horsetail (Equisetum fluviatile), 1 430 Bq kg{sup -1} dry wt; CF 29 200, whereas in another sample of the same species the concentration was only 174 Bq kg{sup -1} dry wt. In addition, the Water lily (Nymphaea candida), Spiked water millfoil (Myriophyllum spicatum), Broad-leaved pondweed (Potamogeton natans) and Yellow water lily (Nuphar lutea) seemed to be good indicators for {sup 137}Cs. The tall freshwater clam (Anodonta sp.) seemed to be a modest accumulator of {sup 137}Cs. Contrary to our results from the coastal areas of the Baltic Sea, many aquatic plants demonstrated in fresh water similar accumulation capacity of {sup 137}Cs as fish (perch and roach), while in the sea the uptake of {sup 137}Cs in fish seemed to be more efficient than in aquatic plants. (LN)

  15. Classical Biological Control of Water Hyacinth, Eichhornia Crassipes (Liliales: Pomteridiaeae), Using Neochentina Spp, Weevils (Curculionidae), During the Re-Inversion Period in the Lake victoria

    Ochiel, G.R.S.

    2002-01-01

    The paper presents recent results from an ongoing classical biological control programme for water hyacinth, implemented by Kenya Agricultural Research Institute Under the Lake Environmental Project. After the successful control of the weed, a re-inversion in the lake was experienced in August 2000 in Nyakach Bay. Between november 2000 and June 2001, approximately 5600 adults Neochetina spp. (coleoptera: Curculionidae) weevils, biological control agents for water hyacinth Eichhornia crassipes (Liliales: Ponteridaceae) were harvested, from the Kibos rearing facility, Namba-Okana 'field security' and community weevil rearing units. Weevils were released on water hyacinth at thirteen sites in Berkeley, Nyakach, Osodo, Kendu, Homa and Karungu and Muhuru Bays, at Kuja-Migori river tributaries and upstream of Nzoia, Yala and Sondu-Miriu rivers. In general, reproductive and growth potential (number of daughter plants, petiole length and laminar area) and fresh weight of the weed was suppressed. there was a gradual increase in insect population levels (number of weevils plant -1 ) and damage to plants by weevil larvae. there is need to carry out an aerial survey to verify the visual estimates of water hyacinth cover and intensify mass rearing and releases of weevils in hotspot areas and to concentrate releases in riverine systems

  16. Simbi Nyaima: An Interplay of Nature and Mythology in the Lake Victoria Region; Planning and Management for Ecotourism Transformation in Kenya

    Fredrick Argwenge Odede

    2014-01-01

    Full Text Available Many countries in the world exploit cultural heritage to reduce poverty, enhance livelihood and transform of the community and support local livelihood. This paper focuses of ecotourism transformation, namely, nature (Simbi as unique Crater Lake and the mythology associated with the lake depicting the curse of a village of a strange old woman by the name Simbi. These two constellations have been used to preserve the site and needs to be used in the planning, conservation and management of this unique heritage. Stakeholder participation should use the two concepts in planning and conservation. The study aimed at mapping the site, examining its cultural identity, assessing the values and potential of the site, identifying the challenges facing the site and developing appropriate strategies for ecotourism promotion. The study used ethnographic and phenomenological modes of data collection using purposive sampling method. The data was qualitatively analysed and yielded themes with respect to research objectives. The documented the location, nature and mythology of the site as planning, conservation and branding tools, established the level of community participation in its planning, conservation and branding, identified its potential and challenges for ecotourism promotion, and proposed appropriate strategies for planning management and conservation of Simbi Nyaima for upscaling ecotourism in the study area.

  17. Holocene and Late Glacial sedimentation near steep slopes in southern Lake Baikal

    Michael Sturm

    2015-07-01

    Full Text Available We here present new data on sedimentation at and near the steep north-slopes of southern Lake Baikal. Short sediment cores were taken at 550 m and at 1366 m water depth, within 3600 m offshore Cape Ivanovskii at the station of the Baikal Deep Underwater NEUTRINO Telescope. The sediments within 3600 m off the northern coast of Southern Lake Baikal are dominated by pelagic deposition. Our data reveal surprisingly little influence from terrigenous material from adjacent coastal areas, tributaries and their catchment. At the shallow-water site (at 550 m water depth, 700 m off shore just 27 cm thick homogenous sediments have accumulated during the Holocene on top of Pleistocene deposits resulting in Holocene sedimentation rates of 0.003 cm a-1. The very low rates are caused by long-term persistent winnowing of fine particles caused by week contour currents along the slope. The uppermost sediments are oxidized down to 22 cm. Very low concentrations of Corg, Sibio and Ntot in Pleistocene sediments increase dramatically within the Holocene. The heavy mineral fraction of the shallow-water sediments contains up to 33.6 % olivine and up to 2.4 % spinel. These rare minerals originate from white marbles of the nearby coastal outcrop Belaya Vyemka of the Early Precambrian Sharyzalgaiskaya Series. At the deep-water site (at 1366 m water depth, 3600 m off shore Holocene sedimentation rates are 10-times higher (0.036 cm a-1. Sediment oxidation occurs just within the uppermost 2 cm. Of the two rare type minerals of the Sharyzalgaiskaya Series spinel does not occur at all and olivine is represented by very diminished concentrations. This indicates insignificant influx of terrestrial material from the nearby shore to the deep-water site . Distal turbidites of far-off sources are intercalated to pelagic sediments at the deep-water site. Breakdown events of deltas at the SE- and S-coast of the basin are suggested to be responsible for the formation of the turbidites

  18. Demographic and Component Allee Effects in Southern Lake Superior Gray Wolves.

    Jennifer L Stenglein

    Full Text Available Recovering populations of carnivores suffering Allee effects risk extinction because positive population growth requires a minimum number of cooperating individuals. Conservationists seldom consider these issues in planning for carnivore recovery because of data limitations, but ignoring Allee effects could lead to overly optimistic predictions for growth and underestimates of extinction risk. We used Bayesian splines to document a demographic Allee effect in the time series of gray wolf (Canis lupus population counts (1980-2011 in the southern Lake Superior region (SLS, Wisconsin and the upper peninsula of Michigan, USA in each of four measures of population growth. We estimated that the population crossed the Allee threshold at roughly 20 wolves in four to five packs. Maximum per-capita population growth occurred in the mid-1990s when there were approximately 135 wolves in the SLS population. To infer mechanisms behind the demographic Allee effect, we evaluated a potential component Allee effect using an individual-based spatially explicit model for gray wolves in the SLS region. Our simulations varied the perception neighborhoods for mate-finding and the mean dispersal distances of wolves. Simulation of wolves with long-distance dispersals and reduced perception neighborhoods were most likely to go extinct or experience Allee effects. These phenomena likely restricted population growth in early years of SLS wolf population recovery.

  19. Trophic interference by Salmo trutta on Aplochiton zebra and Aplochiton taeniatus in southern Patagonian lakes.

    Elgueta, A; González, J; Ruzzante, D E; Walde, S J; Habit, E

    2013-02-01

    The length and mass ratio, diet and isotopic composition of Aplochiton zebra and Aplochiton taeniatus inhabiting a Salmo trutta-invaded and a S. trutta-free lake in southern Patagonia were compared. Results indicate that S. trutta exercises important trophic interference over A. zebra and A. taeniatus, causing changes in their dietary composition by reducing the consumption of winged Diptera through changes in feeding behaviours that involve jumping out of the water. This effect is significantly higher in A. zebra than in A. taeniatus a species that has a highly specialized diet. The dietary changes of A. zebra and A. taeniatus in sympatry with S. trutta lead to an impoverishment of their isotopic nitrogen signals (δ(15)N), suggesting a reduction of their trophic position. In the case of A. zebra, this translates into a significant decrease in its body condition factor. Such interference could lead to a population decline of this species and would explain the current distribution range decline and allopatry with S. trutta in fluvial systems. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  20. Climate and vegetation changes during the Lateglacial and early–middle Holocene at Lake Ledro (southern Alps, Italy

    S. Joannin

    2013-04-01

    Full Text Available Adding to the on-going debate regarding vegetation recolonisation (more particularly the timing in Europe and climate change since the Lateglacial, this study investigates a long sediment core (LL081 from Lake Ledro (652 m a.s.l., southern Alps, Italy. Environmental changes were reconstructed using multiproxy analysis (pollen-based vegetation and climate reconstruction, lake levels, magnetic susceptibility and X-ray fluorescence (XRF measurements recorded climate and land-use changes during the Lateglacial and early–middle Holocene. The well-dated and high-resolution pollen record of Lake Ledro is compared with vegetation records from the southern and northern Alps to trace the history of tree species distribution. An altitude-dependent progressive time delay of the first continuous occurrence of Abies (fir and of the Larix (larch development has been observed since the Lateglacial in the southern Alps. This pattern suggests that the mid-altitude Lake Ledro area was not a refuge and that trees originated from lowlands or hilly areas (e.g. Euganean Hills in northern Italy. Preboreal oscillations (ca. 11 000 cal BP, Boreal oscillations (ca. 10 200, 9300 cal BP and the 8.2 kyr cold event suggest a centennial-scale climate forcing in the studied area. Picea (spruce expansion occurred preferentially around 10 200 and 8200 cal BP in the south-eastern Alps, and therefore reflects the long-lasting cumulative effects of successive boreal and the 8.2 kyr cold event. The extension of Abies is contemporaneous with the 8.2 kyr event, but its development in the southern Alps benefits from the wettest interval 8200–7300 cal BP evidenced in high lake levels, flood activity and pollen-based climate reconstructions. Since ca. 7500 cal BP, a weak signal of pollen-based anthropogenic activities suggest weak human impact. The period between ca. 5700 and ca. 4100 cal BP is considered as a transition period to colder and wetter conditions (particularly during

  1. Budget analysis of Escherichia coli at a southern Lake Michigan Beach

    Thupaki, P.; Phanikumar, M.S.; Beletsky, D.; Schwab, D.J.; Nevers, M.B.; Whitman, R.L.

    2010-01-01

    Escherichia coli (EC) concentrations at two beaches impacted by river plume dynamics in southern Lake Michigan were analyzed using three-dimensional hydrodynamic and transport models. The relative importance of various physical and biological processes influencing the fate and transport of EC were examined via budget analysis and a first-order sensitivity analysis of model parameters. The along-shore advective fluxofEC(CFU/m2·s)was found to be higher compared to its crossshore counterpart; however, the sum of diffusive and advective components was of a comparable magnitude in both directions showing the importance of cross-shore exchange in EC transport. Examination of individual terms in the EC mass balance equation showed that vertical turbulent mixing in the water column dominated the overall EC transport for the summer conditions simulated. Dilution due to advection and diffusion accounted for a large portion of the total EC budget in the nearshore, and the net EC loss rate within the water column (CFU/m3·s) was an order of magnitude smaller compared to the horizontal and vertical transport rates. This result has important implications for modeling EC at recreational beaches; however, the assessment of the magnitude of EC loss rate is complicated due to the strong coupling between vertical exchange and depth-dependent EC loss processes such as sunlight inactivation and settling. Sensitivity analysis indicated that solar inactivation has the greatest impact on EC loss rates. Although these results are site-specific, they clearly bring out the relative importance of various processes involved.

  2. Holocene vegetation dynamics of Taiga forest in the Southern Altai Mountains documented by sediments from Kanas Lake

    Huang, X.; Chen, F.

    2016-12-01

    The Chinese Altai is the southern limit of the Taiga forest of the continent, and regional vegetation dynamics during the Holocene will help us to understand regional climate changes, such as the Siberian High variations. Here we present a pollen-based vegetation and climate reconstruction from a well dated sediment core from Kanas Lake, a deep glacial moraine dammed lake in the Southern Altai Mountains (Chinese Altai). The 244-cm-long sequence spans the last 13,500 years, and the chronology is based on nine accelerator mass spectrometry radiocarbon dates from terrestrial plant macrofossils. At least five stages of regional vegetation history are documented: (i) From 13.5 to 11.7 ka (1 ka = 1000 cal yr BP), Kanas Lake region was occupied by steppe dominated by Artemisia, Chenopodiaceae and grass pollen, with low tree coverage. (ii) From 11.7 to 8.5 ka, regional forest build up dramatically indicated by increasing tree pollen percentages, including Picea, Larix, and the highest Junipers, with decreasing Artemisia and increasing Chenopodiaceae. (iii) From 8.5 to 7.2 ka, the forest around the lake became dense with the maximum content of Picea and Betula pollen types. And the steppe pollen types reached their lowest values. (iv) From 7.2 to 4 ka, as a typical tree species of Taiga forest, Larix pollen percentage became much higher than previous stage, and the sum of trees & shrubs pollen types decreased, which possibly indicated cooler and wetter climate (v) After 4 ka, trees & shrubs (e.g. Betula, Junipers) pollen types decreased, with increasing Artemisia and decreasing Chenopodiaceae, which might indicated more humid and cooler climate in the late Holocene. Comparing to the other pollen records in the Altai Mountains, Lake Grusha and Lake Hoton had recorded a slightly different process of vegetation evolution in the early Holocene, where forest was built up in the northern side of the Chinese Altai faster than that of the Kanas Lake area. And the difference could

  3. Permian salt dissolution, alkaline lake basins, and nuclear-waste storage, Southern High Plains, Texas and New Mexico

    Reeves, C.C. Jr.; Temple, J.M.

    1986-01-01

    Areas of Permian salt dissolution associated with 15 large alkaline lake basins on and adjacent to the Southern High Plains of west Texas and eastern New Mexico suggest formation of the basins by collapse of strata over the dissolution cavities. However, data from 6 other alkaline basins reveal no evidence of underlying salt dissolution. Thus, whether the basins were initiated by subsidence over the salt dissolution areas or whether the salt dissolution was caused by infiltration of overlying lake water is conjectural. However, the fact that the lacustrine fill in Mound Lake greatly exceeds the amount of salt dissolution and subsidence of overlying beds indicates that at least Mound Lake basin was antecedent to the salt dissolution. The association of topography, structure, and dissolution in areas well removed from zones of shallow burial emphasizes the susceptibility of Permian salt-bed dissolution throughout the west Texas-eastern New Mexico area. Such evidence, combined with previous studies documenting salt-bed dissolution in areas surrounding a proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, leads to serious questions about the rationale of using salt beds for nuclear-waste storage

  4. Neutron activation analysis of sediment core samples of Lake Erhai in southern China and a Salt Lake in India

    Toyoda, Kazuhiro; Shinozuka, Yoshitsugu; Miura, Masahiro; Moriyasu, Yuki

    2005-01-01

    The purpose of this research is in the verification of the hypothesis that the long-lived nuclide ratio of Th/Sc in the deposit sample dug up in the lake with the hinterland of the granite quality is the index of a past change of precipitation and of the event such as earthquakes. As a preceding step the relation between an environmental change and a climate change was studied by the measuring result of the ratio of Th/Sc by the neutron activation analysis about the digging core sample of the Nepalese Katmandu basin (For the past 700,000 years) and the core sample (For 40,000 years and 8,000 years of the past) in Lake Biwa. (H. Katsuta)

  5. The importance of bacterial utilization of released phytoplankton photosynthate in two humic forest lakes in southern Finland

    Jones, R.I.; Salonen, K.

    1985-01-01

    Bacterial utilization of photosynthetically fixed dissolved organic carbon (PDOC) released from natural phytoplankton assemblages was studied in two small, extremely humic, forest lakes in southern Finland. Bacterial activity (measured us uptake of 14 C-glucose) and phytoplankton photosynthesis (measured as light uptake of 14 CO 2 ) could be most effectively separated using Nuclepore filters of pore 1-2 μm. Released PDOC was 10-67% of total phytoplankton carbon fixation during in situ experiments, and represented about 0.1% of total DOC. Net uptake of PDOC by bacteria was found to be about 20% during 24 hour laboratory incubations, although about 40% of PDOC present at the start of an experiment could be utilized by bacteria during a 24 hour period. PDOC does not provide a quantitatively important substrate supply fo bacterial respiration in humic forest lakes. (author)

  6. Record of late Pleistocene glaciation and deglaciation in the southern Cascade Range. I. Petrological evidence from lacustrine sediment in Upper Klamath Lake, southern Oregon

    Reynolds, R.L.; Rosenbaum, J.G.; Rapp, J.; Kerwin, M.W.; Bradbury, J.P.; Colman, S.; Adam, D.

    2004-01-01

    Petrological and textural properties of lacustrine sediments from Upper Klamath Lake, Oregon, reflect changing input volumes of glacial flour and thus reveal a detailed glacial history for the southern Cascade Range between about 37 and 15 ka. Magnetic properties vary as a result of mixing different amounts of the highly magnetic, glacially generated detritus with less magnetic, more weathered detritus derived from unglaciated parts of the large catchment. Evidence that the magnetic properties record glacial flour input is based mainly on the strong correlation between bulk sediment particle size and parameters that measure the magnetite content and magnetic mineral freshness. High magnetization corresponds to relatively fine particle size and lower magnetization to coarser particle size. This relation is not found in the Buck Lake core in a nearby, unglaciated catchment. Angular silt-sized volcanic rock fragments containing unaltered magnetite dominate the magnetic fraction in the late Pleistocene sediments but are absent in younger, low magnetization sediments. The finer grained, highly magnetic sediments contain high proportions of planktic diatoms indicative of cold, oligotrophic limnic conditions. Sediment with lower magnetite content contains populations of diatoms indicative of warmer, eutrophic limnic conditions. During the latter part of oxygen isotope stage 3 (about 37-25 ka), the magnetic properties record millennial-scale variations in glacial-flour content. The input of glacial flour was uniformly high during the Last Glacial Maximum, between about 21 and 16 ka. At about 16 ka, magnetite input, both absolute and relative to hematite, decreased abruptly, reflecting a rapid decline in glacially derived detritus. The decrease in magnetite transport into the lake preceded declines in pollen from both grass and sagebrush. A more gradual decrease in heavy mineral content over this interval records sediment starvation with the growth of marshes at the margins

  7. Lake Victoria water resources management challenges and ...

    ... governing management measures capable of meeting the needs of riparian states and ensuring sustainability within the basin is highlighted. Keywords: biodiversity loss; East Africa; eutrophication; heavy metal pollution; international treaties; Nile Basin; shared water resources. African Journal of Aquatic Science 2008, ...

  8. Distribution and dynamics of nitrogen and microbial plankton in southern Lake Michigan during spring transition 1999-2000

    Gardner, Wayne S.; Lavrentyev, Peter J.; Cavaletto, Joann F.; McCarthy, Mark J.; Eadie, Brian J.; Johengen, Thomas H.; Cotner, James B.

    2004-03-01

    Ammonium and amino acid fluxes were examined as indicators of N and microbial food web dynamics in southern Lake Michigan during spring. Either 15NH4+ or a mixture of 15N-labelled amino acids (both at 4 μM N final concentration) was added to Lake Michigan water. Net fluxes were measured over 24 h under natural light and dark conditions using deck-top incubators and compared to microbial food web characteristics. Isotope dilution experiments showed similar light and dark NH4+ regeneration rates at lake (6 versus 5 nM N h-1) and river-influenced (20 versus 24 nM N h-1) sites. Ammonium uptake rates were similar to regeneration rates in dark bottles. Dark uptake (attributed mainly to bacteria) accounted for ˜70% of total uptake (bacteria plus phytoplankton) in the light at most lake sites but only ˜30% of total uptake at river-influenced sites in or near the St. Joseph River mouth (SJRM). Cluster analysis grouped stations having zero, average, or higher than average N-cycling rates. Discriminant analysis indicated that chlorophyll concentration, oligotrich ciliate biomass, and total P concentration could explain 66% of N-cycling rate variation on average. Heterotrophic bacterial N demand was about one third of the NH4+ regeneration rate. Results suggest that, with the exception of SJRM stations, bacterial uptake and protist grazing mediated much of the N dynamics during spring transition. Since NH4+ is more available to bacteria than NO3-, regenerated NH4+ may have a strong influence on spring, lake biochemical energetics by enhancing N-poor organic matter degradation in this NO3- -replete ecosystem.

  9. Water circulation and recharge pathways of coastal lakes along the southern Baltic Sea in northern Poland

    Cieśliński Roman

    2016-12-01

    Full Text Available The purpose of this paper is to describe water circulation patterns for selected lakes found along the Baltic coast in northern Poland and to determine primary recharge mechanisms or pathways that produce an influx or loss of lake water. A secondary purpose of the paper is to determine the magnitude of recharge for each studied source of water – river water influx, surface runoff from direct catchments, forced influx from polders surrounding lakes, and periodic marine water intrusions from the nearby Baltic Sea. It is also important to determine the magnitude of water outflow from lakes to the sea via existing linkages as well as to compare horizontal influx and outflow data. The study area consisted of five lakes located along the Baltic Sea in northern Poland: Łebsko, Gardno, Bukowo, Kopań, Resko Przymorskie. The main driving force of the studied lakes are large rivers that drain lake catchment areas and periodic brackish water intrusions by the Baltic Sea.

  10. Magnetometric investigation of glaciers Southern and Northern Inylchek adjacent to the Merzbacher Lake

    А. Shakirov

    2015-01-01

    Full Text Available Results of areal magnetometric investigation of glaciers South and North Enilchek located in the vicinity of the Merzbaher Lake are presented. These stud- ies resulted in finding of the bow-shaped rock bar (riegel under the South Enilchek Glacier that became one of causes to turn its right flows toward the Merz- bacher Lake. Under the North Enilchek glacier the horseshoe-shaped riegel ledge was also detected, and that one created a barrier to accumulation of bottom sediments and, thus, formed a distinctive soil alluvial dam, which promoted formation of rather wide interface between upper and lower parts of the Merz- bacher Lake

  11. Changes in the flora of the eastern and southern shore area of lake Piaseczno in the years 2003-2010

    Artur Serafin

    2012-12-01

    Full Text Available Changes in the flora composition of the eastern and southern shore area of Lake Piaseczno, with predominantly agricultural and recreational land use in the lake catchment, were examined in the years 2003 and 2010. Multifaceted analysis of the flora was made with regard to its botanical, syntaxonomical, and ecological aspects, the identified species were assigned to different historical-geographical groups and range groups, as well as the flora synanthropisation, anthropophytisation and apophytisation indices were calculated and compared. Both the species number and the species floristic composition of the Lake Piaseczno shore zone changed in seven years. The fact that the value of the synanthropisation index remained at a similar level and a slight increase in the anthropophytisation index values are probably related to the decrease in tourist traffic in this area and the diminishing pressure from extensive agriculture. The results of the flora analysis, in terms of the assignment of species to characteristic ecological groups, confirm the specific habitat conditions in the study area and, above all, significant permeability of the substrate and high soil nutrient availability.

  12. Growth and Survival of Larval Alewife (Alosa pseudoharengus) in Southern New England Lakes

    Suca, J.; Jones, A.; Llopiz, J.

    2016-02-01

    Alewives (Alosa pseudoharengus) are ecologically and commercially important anadromous fish in eastern North America, and populations have declined to close to 1% of their historic levels. Despite moratoriums in recent years in most US states, there has been little recovery of alewives. In light of this poor recovery, we examined the factors that influence the survival of alewife larvae that were spawned in multiple freshwater systems in Massachusetts. Four lakes were sampled each week throughout the spring and summer for fish larvae, zooplankton and physicochemical parameters. Abundances of larvae from the lakes were analyzed, along with environmental factors. In the lab, otoliths of larvae from two different lakes were used for age and growth rate determination, as well as examining selective mortality during the larval period. Additionally, differences in growth and selective mortality of early and late spawned larvae were analyzed to investigate the tradeoffs between spawning early versus late in the spawning season. Abundances varied greatly between lakes and sampling times. Through otolith analysis, differences in growth rates between lakes were observed. This is likely due to differences in either temperature or food availability, and ongoing work quantifying zooplankton abundances will address these potential factors. Interestingly, there was no evidence for selective mortality in the two lakes examined, a result that is consistent with the hypothesis that anadromy in this species evolved as a strategy to minimize predation during the vulnerable larval period.

  13. Sediment pollution in margins of the Lake Guaíba, Southern Brazil.

    de Andrade, Leonardo Capeleto; Tiecher, Tales; de Oliveira, Jessica Souza; Andreazza, Robson; Inda, Alberto Vasconcellos; de Oliveira Camargo, Flávio Anastácio

    2017-12-02

    Sediments are formed by deposition of organic and inorganic particles on depth of water bodies, being an important role in aquatic ecosystems, including destination and potential source of essential nutrients and heavy metals, which may be toxic for living organisms. The Lake Guaíba supplies water for approximately two million people and it is located in the metropolitan region of Porto Alegre, Rio Grande do Sul State, Brazil. Thus, the aim of this study was to evaluate the sediment pollution in the margins of Lake Guaíba in the vicinity of Porto Alegre city. Surface sediment was sampled in 12 sites to assess the concentration of several elements (C, N, P, Fe, Al, Ca, Mg, Na, K, Mn, Ba, Zn, V, Pb, Cu, Cr, Ni, Cd, Mo, and Se) and the mineralogical composition. Sediment in margins of Lake Guaíba presented predominantly (> 95%) sandy fraction in all samples, but with significant differences between evaluated sites. Sediments in the margins of Lake Guaíba showed indications of punctual water pollution with Pb, Cu, Cr, Ni, TOC, TKN, and P, mainly derived from urban streams that flow into the lake. In order to solve these environmental liabilities, public actions should not focus only on Guaíba, but also in the streams that flow into the lake.

  14. Future recovery of acidified lakes in southern Norway predicted by the MAGIC model

    R. F. Wright

    2003-01-01

    Full Text Available The acidification model MAGIC was used to predict recovery of small lakes in southernmost Norway to future reduction of acid deposition. A set of 60 small headwater lakes was sampled annually from either 1986 (35 lakes or 1995 (25 lakes. Future acid deposition was assumed to follow implementation of current agreed legislation, including the Gothenburg protocol. Three scenarios of future N retention were used. Calibration of the sites to the observed time trends (1990–1999 as well as to one point in time considerably increased the robustness of the predictions. The modelled decline in SO4* concentrations in the lakes over the period 1986–2001 matched the observed decline closely. This strongly suggests that soil processes such as SO4 adsorption/desorption and S reduction/oxidation do not delay the response of runoff by more than a few years. The slope of time trends in ANC over the period of observations was less steep than that observed, perhaps because the entire soil column does not interact actively with the soilwater that emerges as runoff. The lakes showed widely differing time trends in NO3 concentrations over the period 1986–2000. The observed trends were not simulated by any of the three N scenarios. A model based on the C/N ratio in soil was insufficient to account for N retention and leaching at these sites. The large differences in modelled NO3, however, produced only minor differences in ANC between the three scenarios. In the year 2050, the difference was only about 5 μeq l-1. Future climate change entailing warming and increased precipitation could also increase NO3 loss to surface waters. SO4* concentrations in the lakes were predicted to decrease in parallel with the future decreases in S deposition. Fully 80% of the expected decline to year 2025, however, had already occurred by the year 2000. Similarly, ANC concentrations were predicted to increase in the future, but again about 67% of the expected change has already

  15. Monitoring Recent Fluctuations of the Southern Pool of Lake Chad Using Multiple Remote Sensing Data: Implications for Water Balance Analysis

    Wenbin Zhu

    2017-10-01

    Full Text Available The drought episodes in the second half of the 20th century have profoundly modified the state of Lake Chad and investigation of its variations is necessary under the new circumstances. Multiple remote sensing observations were used in this paper to study its variation in the recent 25 years. Unlike previous studies, only the southern pool of Lake Chad (SPLC was selected as our study area, because it is the only permanent open water area after the serious lake recession in 1973–1975. Four satellite altimetry products were used for water level retrieval and 904 Landsat TM/ETM+ images were used for lake surface area extraction. Based on the water level (L and surface area (A retrieved (with coinciding dates, linear regression method was used to retrieve the SPLC’s L-A curve, which was then integrated to estimate water volume variations ( Δ V . The results show that the SPLC has been in a relatively stable phase, with a slight increasing trend from 1992 to 2016. On annual average scale, the increase rate of water level, surface area and water volume is 0.5 cm year−1, 0.14 km2 year−1 and 0.007 km3 year−1, respectively. As for the intra-annual variations of the SPLC, the seasonal variation amplitude of water level, lake area and water volume is 1.38 m, 38.08 km2 and 2.00 km3, respectively. The scatterplots between precipitation and Δ V indicate that there is a time lag of about one to two months in the response of water volume variations to precipitation, which makes it possible for us to predict Δ V . The water balance of the SPLC is significantly different from that of the entire Lake Chad. While evaporation accounts for 96% of the lake’s total water losses, only 16% of the SPLC’s losses are consumed by evaporation, with the other 84% offset by outflow.

  16. The geographical conditions of intensity of salty waters intrusions to coastal lakes on Polish Southern Baltic coast

    Cieslinski, R.

    2009-04-01

    Lakes situated on the coast of the southern Baltic function in different conditions than those in which typically inland reservoirs occur. They are situated in the contact zone of two environments: land and sea. These reservoirs together with their direct catchments form specific hydrographic arrangement, in which the course of physical, chemical and biological processes depends on the fact which of these two environments exerts a stronger influence at a given moment. This is important as the lakes situated in the shore zone of the southern Baltic are not exposed to phenomena caused by constant tides, as it is the case in open seas (Ataie-Ashtiani et al., 1999), but only to extreme hydrometeorological conditions, which lead to the formation of the phenomenon of intrusions of sea waters and of damming the free outflow of potamic waters (Demirel, 2004; Cieśliński, Drwal, 2005). What should also be remembered are the local hydrographic, hydrological and morphometric conditions. As a result of intrusions, in the waters of coastal lakes, apart from inland waters there are also waters of sea origin. The proportions of these genetically distinct waters are variable and differ in individual lakes (Grassi, Netti, 2000; Drwal, Cieśliński, 2007). Despite the difference in the causal factor triggering the phenomenon of salt water intrusions, the effect is usually the same as that observed, for instance, in lakes and lagoons of seas with tides (Ishitobi et al., 1999; De Louw, Oude Essink, 2001) and poorly flushed lagoon (Hsing-Juh et al., 2006) or estuaries (Uncles et al., 2002), though the scale of qualitative changes is greater in the case of open seas than in half-closed and closed seas. The status of the research carried out so far enables proposing a hypothesis that chlorides concentrations, as the best indicators for establishing the occurrence of the phenomenon of intrusions, depend not only on the meteorological factor but in some of the lakes on various

  17. Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

    Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

    2018-01-01

    Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300–500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in

  18. Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

    Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

    2018-02-01

    Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300-500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and

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

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

    2016-12-01

    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. Holocene and latest Pleistocene oblique dextral faulting on the southern Inyo Mountains fault, Owens Lake basin, California

    Bacon, S.N.; Jayko, A.S.; McGeehin, J.P.

    2005-01-01

    The Inyo Mountains fault (IMF) is a more or less continuous range-front fault system, with discontinuous late Quaternary activity, at the western base of the Inyo Mountains in Owens Valley, California. The southern section of the IMF trends ???N20??-40?? W for at least 12 km at the base of and within the range front near Keeler in Owens Lake basin. The southern IMF cuts across a relict early Pliocene alluvial fan complex, which has formed shutter ridges and northeast-facing scarps, and which has dextrally offset, well-developed drainages indicating long-term activity. Numerous fault scarps along the mapped trace are northeast-facing, mountain-side down, and developed in both bedrock and younger alluvium, indicating latest Quaternary activity. Latest Quaternary multiple- and single-event scarps that cut alluvium range in height from 0.5 to 3.0 m. The penultimate event on the southern IMF is bracketed between 13,310 and 10,590 cal years B.P., based on radiocarbon dates from faulted alluvium and fissure-fill stratigraphy exposed in a natural wash cut. Evidence of the most recent event is found at many sites along the mapped fault, and, in particular, is seen in an ???0.5-m northeast-facing scarp and several right-stepping en echelon ???0.5-m-deep depressions that pond fine sediment on a younger than 13,310 cal years B.P. alluvial fan. A channel that crosses transverse to this scarp is dextrally offset 2.3 ?? 0.8 m, providing a poorly constrained oblique slip rate of 0.1-0. 3 m/ k.y. The identified tectonic geomorphology and sense of displacement demonstrate that the southern IMF accommodates predominately dextral slip and should be integrated into kinematic fault models of strain distribution in Owens Valley.

  1. Differences in the water-balance components of four lakes in the southern-central Tibetan Plateau

    Biskop, S.; Maussion, F.; Krause, P.; Fink, M.

    2016-01-01

    The contrasting patterns of lake-level fluctuations across the Tibetan Plateau (TP) are indicators of differences in the water balance over the TP. However, little is known about the key hydrological factors controlling this variability. The purpose of this study is to contribute to a more quantitative understanding of these factors for four selected lakes in the southern-central part of the TP: Nam Co and Tangra Yumco (increasing water levels), and Mapam Yumco and Paiku Co (stable or slightly decreasing water levels). We present the results of an integrated approach combining hydrological modeling, atmospheric-model output and remote-sensing data. The J2000g hydrological model was adapted and extended according to the specific characteristics of closed-lake basins on the TP and driven with High Asia Refined analysis (HAR) data at 10 km resolution for the period 2001-2010. Differences in the mean annual water balances among the four basins are primarily related to higher precipitation totals and attributed runoff generation in the Nam Co and Tangra Yumco basins. Precipitation and associated runoff are the main driving forces for inter-annual lake variations. The glacier-meltwater contribution to the total basin runoff volume (between 14 and 30 % averaged over the 10-year period) plays a less important role compared to runoff generation from rainfall and snowmelt in non-glacierized land areas. Nevertheless, using a hypothetical ice-free scenario in the hydrological model, we indicate that ice-melt water constitutes an important water-supply component for Mapam Yumco and Paiku Co, in order to maintain a state close to equilibrium, whereas the water balance in the Nam Co and Tangra Yumco basins remains positive under ice-free conditions. These results highlight the benefits of linking hydrological modeling with atmospheric-model output and satellite-derived data, and the presented approach can be readily transferred to other data-scarce closed lake basins, opening new

  2. Description of Epistylis riograndensis n.sp. (Ciliophora: Peritrichia) found in an artificial lake in Southern Brazil.

    Utz, Laura R P; Farias, Ana Carolina Silva Rodrigues; Freitas, Eduarda Correa; de Araújo, Gabriella Oliveira

    2014-10-03

    Epistylis riograndensis n. sp., a freshwater peritrich hosting symbiotic algae in its cytoplasm, was collected from an artificial lake, in a Botanical garden in Southern Brazil. Its detailed morphology was investigated using live and silver-stained specimens. The colonial sessile E. riograndensis has elongate zooids measuring, on average, 162 μm in length and 45 μm in width. A single contractile vacuole located near the infundibulum and a C-shaped macronucleus located transversely in the adoral half of the cell were also observed. The oral infraciliature revealed in silver-stained specimens was typical of peritrich ciliates. Three infundibular polykineties consisting of 3 rows of kinetosomes were observed. Molecular analyses of 18s rDNA placed E. riograndensis among other Epistylis species in the Order Vorticellida.

  3. Paleoclimatic implications of the hydrogen isotopic composition of terrigenous n-alkanes from Lake Yamzho, southern Tibetan Plateau

    Xia Zhonghuan; Xu Baiqing; Wu Guangjian; Zhu Liping; Muegler Ines; Gleixner, Gerd; Sachse, Dirk

    2009-01-01

    The hydrogen isotopic composition (δD) of leaf water used for biosynthesis of n-alkanes can be modified by climate. Therefore, the δD can be considered as potential paleolimatic proxy to explore. We compared measured δD values of alkanes (n-C 25 to n-C 31 ) extracted from a short sediment profile spanning the past 50 years with a 7-year resolution from Lake Yamzho, southern Tibetan Plateau. Climatic control was reconstructed using meteorological records of the nearby Langkazi and Lhasa weather stations. We found that the δD values of the n-alkanes correlated with the mean annular air temperature and significantly correlated with the mean growing season air temperature. On the other hand, the δD values show poor correlations with both rainfall amount and relative humidity. These results indicate that stable isotope composition of n-alkanes could be an excellent proxy for paleotemperature reconstruction. (author)

  4. Changes in ice cover thickness and lake level of Lake Hoare, Antarctica - Implications for local climatic change

    Wharton, Robert A., Jr.; Mckay, Christopher P.; Clow, Gary D.; Andersen, Dale T.; Simmons, George M., Jr.; Love, F. G.

    1992-01-01

    Results are reported from 10 years of ice-thickness measurements at perennially ice-covered Lake Hoare in southern Victoria Land, Antarctica. The ice cover of this lake had been thinning steadily at a rate exceeding 20 cm/yr during the last decade but seems to have recently stabilized at a thickness of 3.3 m. Data concerning lake level and degree-days above freezing are presented to show the relationship between peak summer temperatures and the volume of glacier-derived meltwater entering Lake Hoare each summer. From these latter data it is inferred that peak summer temperatures have been above 0 C for a progressively longer period of time each year since 1972. Possible explanations for the thinning of the lake ice are considered. The thickness of the ice cover is determined by the balance between freezing during the winter and ablation that occurs all year but maximizes in summer. It is suggested that the term most likely responsible for the change in the ice cover thickness at Lake Hoare is the extent of summer melting, consistent with the rising lake levels.

  5. Apparent rates of production and loss of dissolved gaseous mercury (DGM) in a southern reservoir lake (Tennessee, USA)

    Zhang Hong; Dill, Christopher

    2008-01-01

    Apparent rates of dissolved gaseous mercury (DGM) concentration changes in a southern reservoir lake (Cane Creek Lake, Cookeville, Tennessee) were investigated using the DGM data collected in a 12-month study from June 2003 to May 2004. The monthly mean apparent DGM production rates rose from January (3.2 pg L -1 /h), peaked in the summer months (June-August: 8.9, 8.0, 8.6 pg L -1 /h), and fell to the lowest in December (1.6 pg L -1 /h); this trend followed the monthly insolation march for both global solar radiation and UVA radiation. The monthly apparent DGM loss rates failed to show the similar trend with no consistent pattern recognizable. The spring and summer had higher seasonal mean apparent DGM production rates than the fall and winter (6.8, 9.0, 3.9, 5.0 pg L -1 /h, respectively), and the seasonal trend also appeared to closely follow the solar radiation variation. The seasonal apparent DGM loss featured similar rate values for the four seasons (5.5, 4.3, 3.3, and 3.9 pg L -1 /h for spring, summer, fall, and winter, respectively). Correlation was found of the seasonal mean apparent DGM production rate with the seasonal mean morning solar radiation (r = 0.9084, p < 0.01) and with the seasonal mean morning UVA radiation (r = 0.9582, p < 0.01). No significant correlation was found between the seasonal apparent DGM loss rate and the corresponding afternoon solar radiation (r = 0.5686 for global radiation and 0.6098 for UVA radiation). These results suggest that DGM production in the lake engaged certain photochemical processes, either primary or secondary, but the DGM loss was probably driven by some dark processes

  6. A 150 kyr-long hydroclimate record from Southern California using Searles Lake sediments: initial findings

    Stroup, J. S.; Olson, K. J.; McGee, D.; Lowenstein, T. K.; Smoot, J. P.; Janick, J. J.; Lund, S.; Peaple, M.; Chen, C. Y.; Feakins, S. J.; Litwin, R.

    2017-12-01

    Over decadal to millennial scales, the southwestern U.S has experienced large shifts in hydroclimate ranging from pluvial conditions to extreme droughts. Direct observations, modeling and proxy data suggest precipitation amount and distribution are controlled by multiple factors including the position of the Hadley Cell, strength of the Aleutian Low and North Pacific High, ENSO and the path of winter storm tracks. Sediment records from closed basin lakes provide a means for assessing how hydrologic conditions have responded to past climate changes; however, long (>50 ka) paleoclimate records from lakes are rare and high-resolution age models are challenging to obtain. Searles Lake, in southeastern California, contains a sedimentary record that spans from the Holocene to the Pliocene at high resolution. Previous drill core studies from the basin used stratigraphy and sediment mineralogy to interpret paleoenvironmental changes and have demonstrated that the lake's sediments are able to be precisely dated. These results provide a strong foundation for new high-resolution investigations of the lake sediments. In January 2017, our group collected a new 80 m-long core with the aim of reconstructing hydrologic changes over the last 150 ka at millennial or better resolution. The core was split at the National Lacustrine Core Facility (LacCore) in June. The core contains alternating evaporite layers and finely laminated muds which likely indicate times of dryer and wetter conditions. Despite the challenge of alternating lithologies, core recovery and quality are extremely high. Here, we will present our initial chronological and stratigraphic findings. The core record will be dated using a combination of U/Th, 14C and magnetostratigraphy. We will compare our initial stratigraphic description to the existing Searles Lake literature as well as other records from the region, such as data from Devils Hole. These results provide the framework upon which we will develop detailed

  7. Historical Evolution of the Hydrological Functioning of the Old Lake Xochimilco, Southern Mexico Basin

    Gonzalez, T.; Ruvalcaba, A.

    2012-12-01

    The lacustrian area of Xochimilco is one of the remnants of the old system of lakes located in the Basin of Mexico. After the Spanish conquest, began a series of actions including hydraulic-works that have changed the original landscape of this region. This region had important springs that for more than 50 years supplied water to the Mexico City. Since 1960, the excessive exploitation of the aquifer and urban growth in the region exhausted the springs. Using historical information we were able to characterize the major phenomena that have substantially changed the hydrogeological functioning of the region, in some more than 100 years. Currently, the exploitation of extraction wells has caused a gradual decrease in their static level and the existing remnant of the old lake is maintained with treated water. Observable effects are presented. The topographic gradient has been modified occurs subsidence and fractures are visible besides a severe reduction in the lake area which has been reduced to 15% of its original extent.

  8. Stable carbon and oxygen isotope studies of Late Weichselian lake sediments in southern Sweden and northern Poland, with palaeoclimatic implications

    Hammarlund, D.

    1994-04-01

    Late Weichselian lacustrine sediment sequences from southern Sweden and northern Poland were studied by means of stable isotope analysis in order to reconstruct the climatic development and climatically induced environmental changes in the respective regions. The methods used include analyses of the stable carbon isotope composition (δ 13 C) of bulk organic material, and the stable carbon and oxygen isotope compositions (δ 13 C, δ 18 O) of bulk carbonates and carbonate shells of aquatic organisms. These results were complemented and supported by lithological, chemical and biostratigraphic data (plant macrofossils, insects, molluscs). Chronological data were obtained by AMS radiocarbon dates and correlations based on pollen analysis. At c. 12.400 BP a climatic change from arctic, dry, and continental, to subarctic and more humid and maritime conditions occurred in southern Sweden. The Older Dryas stadial (c.12.200-12.000 BP) is characterized by a temporary return to generally colder , drier, and more continental conditions, followed by generally favourable (subarctic), although unstable, climatic conditions. At c. 11.300 BP a gradual transition towards a colder and more continental climate was initiated, followed by total absence of limnic carbonates during the Younger Dryas stadial (c. 11.000-10.200 BP), indicating arctic and continental conditions. The transition to the Holocene is characterized by a rapid and strong climatic warming. The results from northern Poland point to some important differences compared to this development. A climatic warming around 13.000 BP was followed by generally favourable climatic conditions enabling continuous sedimentation of limnic carbonates during the Late Weichselian. Distinct depletions of 13 C in lacustrine organic material at the transition to the Holocene were recorded in southern Sweden, also demonstrated by decreasing mean values obtained from an extensive compilation of δ 13 C data. A number of processes that may

  9. A radical shift from soft-water to hard-water lake: palaeolimnological evidence from Lake Kooraste Kõverjärv, southern Estonia

    Tiiu Alliksaar

    2012-11-01

    Full Text Available The Water Framework Directive (WFD of the European Union requires the quality of all European water bodies to be examined, and aims to achieve good status by 2015. This study was initiated to assess whether a potential reference lake for identifying lake-type specific reference conditions meets the WFD requirements, of being minimally impacted by human activity during the last centuries. The sediments of Lake Kooraste Kõverjärv were analysed for diatom assemblages and sediment composition; past changes in the lake-water pH and total phosphorus were reconstructed, using quantitative models on sedimentary diatoms. The chronology of sediments was established, using spheroidal fly-ash particles stratigraphy. Palaeolimnological investigations, supported by information from historical maps, revealed that man-made changes around the lake have severely influenced its ecological conditions. The lake, which had been oligotrophic with soft and clear water before the mid-17th century, has been trans­formed into a hard-water lake by modifications to the inflow and outflow. The lake water quality has also been altered by the infiltration of nutrients from a nearby hypertrophic lake that was used for flax retting since the 19th century. Although the ecological status of the lake has remained good despite all these changes, it is still questionable whether to nominate it as a reference lake for stratified hard-water lake types.

  10. Alien species of fish parasites in the coastal lakes and lagoons of the southern Baltic

    Jolanta Morozińska-Gogol

    2009-03-01

    Full Text Available Alien species are now found all over the world. New fish parasites have been unintentionally introduced with infected alien fish imported for aquaculture or have sometimes spread with their intermediate invertebrate hosts transported in the ballast waters of ships. Four alien fish parasites have been recorded in Polish coastal lakes and lagoons, all parasitising eels. Three were introduced with the final host - the Japanese eel - introduced for aquaculture (Anguillicola crassus, Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and one (Paratenuisentis ambiguus with its sole intermediate host (Gammarus tigrinus.

  11. Evaluating local rules and practices for avoiding tragedies in small-scale fisheries of oxbow lakes, Southern Bangladesh

    Abdullah Al Mamun

    2015-09-01

    Full Text Available One of the key issues facing fishery managers, policy-makers and researchers has been acknowledging local institutions and rule systems for managing common pool resources. In this paper, we discuss local institutions and rule systems of community fisheries from two oxbow lake Fisheries in Southern Bangladesh. Both of the fisheries have been under private and state management systems resulting in different management outcomes. Control of fishers and stocking for production enhancement have been key management options of the lakes, but progress has not been satisfactory due to higher associated costs of management and uneven resource benefits distribution. On the other hand, community fisheries have focused on sharing benefits, controlling access, avoiding conflict and maintaining ecosystem health. Community fisheries have been managed through local rules and management practices above and beyond government regulations. Taking community fisheries in Bangladesh as a model fisheries and examining local rules as an effective means of controlling fisher access to a common resource, we explore here the impacts of local rules that have had different levels of governance outcomes in relation to state and private systems. Data were collected using semi-structured interviews (40 individuals and group meetings (one for each site covering 15–20 individuals. Reviews of secondary records also support the analysis. Findings of this study highlight the advantages of local rules and also raise questions about how differential property rights and lack of negotiation power of local communities have constrained the success of community fisheries. At the group level, the capacity of local fishers to make their own rules and implement them locally is a critical factor for community fisheries systems.

  12. victoria cross awards warrants concerning the victoria cross (1920)

    1. WARRANTS CONCERNING THE. VICTORIA CROSS (1920). In order to get a picture of the Royal Warrants promulgated from 1856 to 1920 in respect of the .... to confirmation by us. Eighthly. - It is ordained, where such an act shall not have been performed in the sight of a commanding officer as aforesaid, then the ...

  13. Early Holocene estuary development of the Hesselø Bay area, southern Kattegat, Denmark and its implication for Ancylus Lake drainage

    Bendixen, Carina; Boldreel, Lars Ole; Jensen, Jørn Bo; Bennike, Ole; Hübscher, Christian; Clausen, Ole Rønø

    2017-12-01

    High-resolution shallow seismic data, sediment core information, radiocarbon dating and sequence stratigraphy have been used to interpret the late glacial to early Holocene geological evolution of Hesselø Bay in the southern Kattegat, Denmark. A reconstruction of the early Holocene coastal environment and a description of coastal processes associated with a river outlet into the bay are presented. Weichselian glacial deposits form the lowermost interpreted unit, covered by late glacial (LG) and postglacial (PG, Holocene) sediments. A funnel-shaped estuary existed at the mouth of channels in the period 10.3-9.2 cal. ka BP; the channels drained water from south to north. The early PG is characterised by estuarine and coastal deposits. The early Holocene bars that developed in the estuary are preserved as morphological features on the present-day seabed, possibly as a result of rapid relative sea-level rise. The estuary existed simultaneously with the occurrence and drainage of the Ancylus Lake. The drainage of this lake occurred through the Dana River (palaeo-Great Belt channel) into the southern Kattegat and then into the study area. The level of the Ancylus Lake in the Baltic Sea region dropped significantly at about 10.2 cal. ka BP at the same time as the estuary developed in the Kattegat region. One outcome of the present study is an enhanced understanding of the Ancylus Lake drainage path. No evidence of major erosion is seen, which indicates non-catastrophic continuous water flow from the south without major drainage events of the Ancylus Lake to the southern Kattegat. During the Littorina transgression, coastal estuarine conditions characterized the Hesselø Bay area where elongated ridges formed a bar system. As the Littorina transgression continued, back-stepping of the bar system and coastline occurred. When the transgression breached the Great Belt threshold, flooding caused major erosion throughout the study area.

  14. Four-thousand-year-old gold artifacts from the Lake Titicaca basin, southern Peru.

    Aldenderfer, Mark; Craig, Nathan M; Speakman, Robert J; Popelka-Filcoff, Rachel

    2008-04-01

    Artifacts of cold-hammered native gold have been discovered in a secure and undisturbed Terminal Archaic burial context at Jiskairumoko, a multicomponent Late Archaic-Early Formative period site in the southwestern Lake Titicaca basin, Peru. The burial dates to 3776 to 3690 carbon-14 years before the present (2155 to 1936 calendar years B.C.), making this the earliest worked gold recovered to date not only from the Andes, but from the Americas as well. This discovery lends support to the hypothesis that the earliest metalworking in the Andes was experimentation with native gold. The presence of gold in a society of low-level food producers undergoing social and economic transformations coincident with the onset of sedentary life is an indicator of possible early social inequality and aggrandizing behavior and further shows that hereditary elites and a societal capacity to create significant agricultural surpluses are not requisite for the emergence of metalworking traditions.

  15. Direct evidence of 1,900 years of indigenous silver production in the Lake Titicaca Basin of Southern Peru.

    Schultze, Carol A; Stanish, Charles; Scott, David A; Rehren, Thilo; Kuehner, Scott; Feathers, James K

    2009-10-13

    Archaeological excavations at a U-shaped pyramid in the northern Lake Titicaca Basin of Peru have documented a continuous 5-m-deep stratigraphic sequence of metalworking remains. The sequence begins in the first millennium AD and ends in the Spanish Colonial period ca. AD 1600. The earliest dates associated with silver production are 1960 + or - 40 BP (2-sigma cal. 40 BC to AD 120) and 1870 + or - 40 BP (2-sigma cal. AD 60 to 240) representing the oldest known silver smelting in South America. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis of production debris indicate a complex, multistage, high temperature technology for producing silver throughout the archaeological sequence. These data hold significant theoretical implications including the following: (i) silver production occurred before the development of the first southern Andean state of Tiwanaku, (ii) the location and process of silverworking remained consistent for 1,500 years even though political control of the area cycled between expansionist states and smaller chiefly polities, and (iii) that U-shaped structures were the location of ceremonial, residential, and industrial activities.

  16. Atmospheric Mercury Transport Across Southern Lake Michigan: Influence from the Chicago/Gary Urban Area

    Gratz, L. E.; Keeler, G. J.; Dvonch, J. T.

    2008-12-01

    The local and regional impacts of mercury emissions from major urban and industrial areas are critical to quantify in order to further understand mercury cycling in the environment. The Chicago/Gary urban area is one such location in which mercury emissions from industrial sources are significant and regional mercury transport needs to be further examined. Speciated atmospheric mercury was measured in Chicago, IL and Holland, MI from July to November 2007 to better characterize the impact of Chicago/Gary on southwest Michigan. Previous work under the 1994-1995 Lake Michigan Mass Balance Study (LMMBS) indicated that the highest levels of mercury deposition in southwest Michigan occurred with transport from the Chicago/Gary area, particularly with rapid transport where less mercury was deposited close to sources(1). However, at that time it was not possible to measure reactive gas phase mercury (RGM), a highly-soluble form of mercury in industrial emissions that is readily removed from the atmosphere. Since the LMMBS, the development of speciated mercury systems has made it possible to continuously monitor gaseous elemental mercury (Hg0), particulate mercury (HgP), and RGM. These measurements are useful for understanding atmospheric mercury chemistry and differentiating between local and regional source impacts due to the different behaviors of reactive and elemental mercury. Results from 2007 show that, on average, Hg0 and HgP were 1.5 times higher and RGM was 2 times higher in Chicago than in Holland. Mean mercury wet deposition was nearly 3 times higher in Chicago than in Holland. Meteorological analysis indicates that transport across the lake from Chicago/Gary occurred frequently during the study. Additional measurements of O3, SO2, meteorological parameters, event mercury and trace element precipitation samples, and modeled back-trajectories are used to discern regional transport events from local deposition and characterize the impact of the Chicago/Gary urban

  17. A toxic cyanobacterial bloom in an urban coastal lake, Rio Grande do Sul state, Southern Brazil

    Luciana Retz de Carvalho

    2008-12-01

    Full Text Available Reports of cyanobacterial blooms developing worldwide have considerably increased, and, in most cases, the predominant toxins are microcystins. The present study reports a cyanobacterial bloom in Lake Violão, Torres, Rio Grande do Sul State, in January 2005. Samples collected on January 13, 2005, were submitted to taxonomical, toxicological, and chemical studies. The taxonomical analysis showed many different species of cyanobacteria, and that Microcystis protocystis and Sphaerocavum cf. brasiliense were dominant. Besides these, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii, and Anabaenopsis elenkinii f. circularis were also present. The toxicity of the bloom was confirmed through intraperitoneal tests in mice, and chemical analyses of bloom extracts showed that the major substance was anabaenopeptin F, followed by anabaenopeptin B, microcystin-LR, and microcystin-RR.O número de relatos de ocorrências de florações de cianobactérias em todo o mundo vem aumentando consideravelmente e na maioria desses episódios, as toxinas dominantes são as microcistinas. O presente estudo relata a ocorrência de floração na Lagoa do Violão, município de Torres, RS, em janeiro de 2005. As amostras coletadas em 13/01/2005 foram submetidas a estudos taxonômicos, toxicológicos e químicos. O exame microscópico do fitoplancton mostrou a dominância das espécies Microcystis protocystis e Sphaerocavum cf. brasiliense; foram observadas, também, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii e Anabaenopsis elenkinii f. circularis. A toxicidade da floração foi confirmada através de ensaio intraperitonial em camundongos e a análise química de extratos obtidos da biomassa liofilizada mostrou que a substância majoritária era a anabaenopeptina F, seguida por anabaenopeptina B, microcistina-LR e microcistina-RR.

  18. Climate variability during the deglaciation and Holocene in a high-altitude alpine lake deduced from the sedimentary record from Laguna Seca, Sierra Nevada, southern Iberian Peninsula

    Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Anderson, R. Scott

    2017-04-01

    High-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), color and lithological analyses have been carried out on a 3.6 m-long sediment core from Laguna Seca, a high-elevation dry lake from Sierra Nevada mountain range, southern Spain. This is the longest sedimentary record retrieved from an alpine lake in southern Iberian Peninsula. Besides, alpine lakes are very sensitive environments to climate changes and previous studies showed that Laguna Seca could provide an excellent record to identify millennial-scale climate variations during deglaciation and the whole Holocene. XRF analyses, in particular high calcium and low K/Ca ratios, show aridity phases, very well represented during Last Glacial Maximum (LGM) and the Younger Dryas (YD). Arid events are also shown at ca. 8.1 ka BP, ca. 4.4 ka BP and the latest Holocene. On the other hand, negative values in calcium and positive values in K/Ca appear in the Bølling-Allerød (BA) and during the early Holocene until ca. 6 ka BP, indicating more humidity and higher run-off. A progressive aridification trend is also observed in the Holocene, changing from more humid conditions during the early Holocene to more aridity during the late Holocene.

  19. Detection of Schistosoma Antibodies and exploration of associated factors among local residents around Inlay Lake, Southern Shan State, Myanmar.

    Soe, Htin Zaw; Oo, Cho Cho; Myat, Tin Ohn; Maung, Nay Soe

    2017-03-01

    Schistosomiasis is a chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. Its transmission has been reported in 78 countries affecting at least 258 million people world-wide. It was documented that S. japonicum species was prevalent in Shan State, Myanmar, but the serological study was not conducted yet. General objective of the present study was to detect schistosoma antibodies and explore associated factors among local residents living around Inlay Lake, Nyaung Shwe Township, and Southern Shan State, Myanmar. An exploratory and cross-sectional analytic study was conducted among local residents (n = 315) in selected rural health center (RHC) areas from December 2012 through June 2013. The participants were interviewed with pretested semi-structured questionnaires and their blood samples (serum) were tested using Schistosomiasis Serology Microwell ELISA test kits (sensitivity 100% and specificity 85%) which detected IgG antibodies but could not distinguish between a new and past infection. Data collected were analysed by SPSS software 16.0 and associations of variables were determined by Chi-squared test with a significant level set at 0.05. Schistosoma seroprevalence (IgG) in study area was found to be 23.8% (95% CI: 18.8-28.8%). The present study is the first and foremost study producing serological evidence of schistosoma infection-one of the neglected tropical diseases-in local people of Myanmar. The factors significantly associated with seropositivity were being male [OR = 2.6 (95% CI: 1.5-4.49), P Myanmar, and this should be further confirmed parasitologically and kept under surveillance. Proper trainings on diagnosis, treatment, prevention and control of schistosomiasis should be provided to the healthcare providers. ISRCTN ISRCTN73824458 . Registered 28 September 2014, retrospectively registered.

  20. Unravelling aquifer-wetland interaction using CSAMT and gravity methods: the Mollina-Camorra aquifer and the Fuente de Piedra playa-lake, southern Spain

    Pedrera, A.; Martos-Rosillo, S.; Galindo-Zaldívar, J.; Rodríguez-Rodríguez, M.; Benavente, J.; Martín-Rodríguez, J. F.; Zúñiga-López, M. I.

    2016-06-01

    The hydrological regime of Fuente de Piedra playa-lake (Málaga, southern Spain) has been significantly affected by the intensive exploitation of groundwater in the area. The playa-lake is situated above clays, marls, and gypsum, and under unaltered conditions received surface-subsurface runoff within the watershed as well as groundwater discharge from two carbonate aquifers. We have analyzed the structure of the main one, the Mollina-Camorra carbonate aquifer, by combining controlled source audio magnetotellurics (CSAMT), gravity prospecting, and time-domain electromagnetic (TDEM) soundings. This geophysical information, together with new structural and hydrogeological data, was gathered to develop a new conceptual hydrogeological model. This model allows the hydrological linkage of the carbonate aquifer with the playa-lake system to be established. Moreover, the intensive exploitation in the carbonate aquifer, even outside the watershed of the playa-lake, has affected the hydrological regime of the system. This multidisciplinary work demonstrates the potential of geophysical methods for understanding wetland-aquifer interaction, having important groundwater management implications.

  1. Spatially Modeling the Impact of Terrain on Wind Speed and Dry Particle Deposition Across Lake Perris in Southern California to Determine In Situ Sensor Placement

    Brooks, A. N.

    2014-12-01

    While developed countries have implemented engineering techniques and sanitation technologies to keep water resources clean from runoff and ground contamination, air pollution and its contribution of harmful contaminants to our water resources has yet to be fully understood and managed. Due to the large spatial and temporal extent and subsequent computational intensity required to understand atmospheric deposition as a pollutant source, a geographic information system (GIS) was utilized. This project developed a multi-step workflow to better define the placement of in situ sensors on Lake Perris in Southern California. Utilizing a variety of technologies including ArcGIS 10.1 with 3D and Spatial Analyst extensions and WindNinja, the impact of terrain on wind speed and direction was simulated and the spatial distribution of contaminant deposition across Lake Perris was calculated as flux. Specifically, the flux of particulate matter (PM10) at the air - water interface of a lake surface was quantified by season for the year of 2009. Integrated Surface Hourly (ISH) wind speed and direction data and ground station air quality measurements from the California Air Resources Board were processed and integrated for use within ModelBuilder. Results indicate that surface areas nearest Alessandro Island and the dam of Lake Perris should be avoided when placing in situ sensors. Furthermore, the location of sensor placement is dependent on seasonal fluctuations of PM10 which can be modeled using the techniques used in this study.

  2. A chronology of the PY608E–PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon

    Watanabe, Takahiro; Nakamura, Toshio; Matsunaka, Tetsuya; Nara, Fumiko Watanabe; Zhu Liping; Wang Junbo; Kakegawa, Takeshi; Nishimura, Mitsugu

    2013-01-01

    Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E–PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.

  3. A chronology of the PY608E-PC sediment core (Lake Pumoyum Co, southern Tibetan Plateau) based on radiocarbon dating of total organic carbon

    Watanabe, Takahiro, E-mail: twatanabe@geo.kankyo.tohoku.ac.jp [Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nakamura, Toshio [Center for Chronological Research, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601 (Japan); Matsunaka, Tetsuya [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan); Nara, Fumiko Watanabe [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Zhu Liping; Wang Junbo [Institute of Tibetan Plateau Research, Chinese Academy of Science, No. 18 Shuangqing Road, Haidian District, Beijing 100085 (China); Kakegawa, Takeshi [Graduate School of Science, Tohoku University, 6-3 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8578 (Japan); Nishimura, Mitsugu [School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424-0902 (Japan)

    2013-01-15

    Paleoclimatic records from the Tibetan Plateau provide important clues for understanding the Asian monsoon and Asian climate systems. To reconstruct climatic and environmental changes in the southern Tibetan Plateau, a 3.77-m-long sediment core (PY608E-PC) was taken from the southeastern part of Lake Pumoyum Co in August 2006. Because terrestrial plant residues are extremely rare in this core, we performed radiocarbon dating on the total organic carbon fraction. We also estimated the old carbon effect and radiocarbon reservoir age of the total organic carbon fraction. Using these estimates, we propose a new radiocarbon chronology for past climatic changes from ca. 12,500 to 700 cal BP. The linear sedimentation rate of the core was founded to be constant at 32.0 cm/kyr, indicating stable sedimentation conditions in Lake Pumoyum Co from the period of the Younger Dryas to the Holocene.

  4. Features of acid-saline systems of Southern Australia

    Dickson, Bruce L.; Giblin, Angela M.

    2009-01-01

    The discovery of layered, SO 4 -rich sediments on the Meridiani Planum on Mars has focused attention on understanding the formation of acid-saline lakes. Many salt lakes have formed in southern Australia where regional groundwaters are characterized by acidity and high salinity and show features that might be expected in the Meridiani sediments. Many (but not all) of the acid-saline Australian groundwaters are found where underlying Tertiary sediments are sulfide-rich. When waters from the formations come to the surface or interact with oxidised meteoric water, acid groundwaters result. In this paper examples of such waters around Lake Tyrrell, Victoria, and Lake Dey-Dey, South Australia, are reviewed. The acid-saline groundwaters typically have dissolved solids of 30-60 g/L and pH commonly 4 and MgSO 4 ) or differential separation of elements with differing solubility (K, Na, Ti, Cr). Thus, it is considered unlikely that groundwaters or evaporative salt-lake systems, as found on earth, were involved. Instead, these features point to a water-poor system with local alteration and very little mobilization of elements

  5. The business of environmental conservation: how nature has become a new strategy of capitalist accumulation in the Andean lake area of Los Ríos, in southern Chile

    De Matheus e Silva, Luis Fernando; Zunino, Hugo Marcelo; Huiliñir Curío, Viviana

    2018-01-01

    Today, “nature” has turned into the target of a new strategy of capitalistic accumulation and in many locations the meaning that ascribed to places has shifted, taken advantages of unique ecological and landscape characteristics. This is the case of the Andean lake region of Los Ríos, in southern Chile. At the end of the 19th century, this place was joined to the national economy by means of the forestry industry. Nevertheless, from the decade of 1990, depending on the conditions generated by...

  6. Forecasting the evolution in the mixing regime of a deep subalpine lake under climate change scenarios through numerical modelling (Lake Maggiore, Northern Italy/Southern Switzerland)

    Fenocchi, Andrea; Rogora, Michela; Sibilla, Stefano; Ciampittiello, Marzia; Dresti, Claudia

    2018-01-01

    The impact of air temperature rise is eminent for the large deep lakes in the Italian subalpine district, climate change being caused there by both natural phenomena and anthropogenic greenhouse-gases (GHG) emissions. These oligomictic lakes are experiencing a decrease in the frequency of winter full turnover and an intensification of stability. As a result, hypolimnetic oxygen concentrations are decreasing and nutrients are accumulating in bottom water, with effects on the whole ecosystem functioning. Forecasting the future evolution of the mixing pattern is relevant to assess if a reduction in GHG releases would be able to revert such processes. The study focuses on Lake Maggiore, for which the thermal structure evolution under climate change in the 2016-2085 period was assessed through numerical simulations, performed with the General Lake Model (GLM). Different prospects of regional air temperature rise were considered, given by the Swiss Climate Change Scenarios CH2011. Multiple realisations were performed for each scenario to obtain robust statistical predictions, adopting random series of meteorological data produced with the Vector-Autoregressive Weather Generator (VG). Results show that a reversion in the increasing thermal stability would be possible only if global GHG emissions started to be reduced by 2020, allowing an equilibrium mixing regime to be restored by the end of the twenty-first century. Otherwise, persistent lack of complete-mixing, severe water warming and extensive effects on water quality are to be expected for the centuries to come. These projections can be extended to the other lakes in the subalpine district.

  7. The Ambrosia Lake project archaeological investigations of three small sites associated with the southern Chacoan outlier of Kin Nizhoni, McKinley County, New Mexico

    Cullington, B.J.

    1990-01-01

    During the fall of 1987, Complete Archaeological Service Associates conducted mitigative excavations at three sites (LA50363, LA50364, and LA50371) in McKinley County, New Mexico. These sites are adjacent to the Phillips/United Nuclear Inactive Uranium Mill and Tailings site at Ambrosia Lake, New Mexico. The primary deposition at each of these sites appears to be related to a Pueblo II or Bonito Phase occupation. Temporal placement is based primarily on the cross dating of ceramics and archaeomagnetic determinations when possible. No tree-ring or radiocarbon samples are available from these sites. These Ambrosia Lake sites indicate that this area was occupied primarily by Pueblo II people who may have had close social, economic, and ceremonial ties with the people living at the nuclear community of Lower Nizhoni about 3 km south-southeast. The later component at LA50364 indicates a Pueblo III occupation by people who may have had similar ties to the people of the Kin Nizhoni nuclear community. The Ambrosia Lake sites, then, provide important information on the structure of subnuclear communities within the southern Chaco periphery

  8. The influence of environmental variables on spatial and temporal phytoplankton dissimilarity in a large shallow subtropical lake (Lake Mangueira, southern Brazil

    Luciane Oliveira Crossetti

    2014-06-01

    Full Text Available AIM: The uneven distribution of organisms in aquatic ecosystems is generally attributed to environmental heterogeneity in both space and time, reflecting the occurrence of appropriate environmental conditions and the availability of resources to biological communities. The aim of this study was to understand how the dissimilarity of the phytoplankton community in a large subtropical shallow lake is related to environmental dissimilarities. METHODS: Biotic and environmental data were gathered at 19 sites along the 90-km length of Lake Mangueira. Sampling was carried out quarterly during 2010 and 2011, totaling 152 sampling units. The relationship between phytoplankton dissimilarity and the dissimilarity of environmental variables was assessed by the BioEnv analysis. MAJOR RESULTS: There is a significant relationship between phytoplankton dissimilarity and environmental dissimilarity. The model that best explained the dissimilarity of phytoplankton among the sampling units included pH, turbidity and nitrate. CONCLUSIONS: The dissimilarity of phytoplankton was related to the dissimilarity, which were directly associated to the variability of conditions and resources in space and time in Lake Mangueira.

  9. Comparison of groundwater quality from forested (Waimarino River), urban (Turangi), and natural wetland (South Taupo Wetlands) subcatchments at the southern end of Lake Taupo

    Rosen, M.R.; Reeves, R.R.; Eser, P.; Chague-Goff, C.; Coshell, L.

    1998-01-01

    Comparison of groundwater quality of three different land uses, (1) exotic pine plantation ready for harvest (Waimarino River Catchment), (2) an urban area characterised by a land treatment facility for sewage effluent from Turangi (Turangi oxidation ponds), and (3) a natural wetland (South Taupo Wetlands) demonstrates that groundwater quality in the southern region of the Lake Taupo catchment is controlled by both natural and human influences in the area. Comparative water quality issues can be summarised as follows. (1) Naturally high concentrations of reduced iron and manganese are present in all three study areas, with the highest concentrations found in the natural wetland area and around the Turangi land treatment facility. (2) Concentrations of sodium, chloride, potassium, and ammonium in the groundwater down-gradient of the Turangi oxidation ponds are elevated relative to the other two study areas. Stable isotopic signatures also show that the groundwater has been influenced by surface water from the oxidation ponds, mostly due to additional evaporation caused by the relatively long residence time of the water (125 days) in the oxidation ponds. Elevated concentrations of ammonium also occur in deep groundwater under the forest areas of the Waimarino River catchment. (3) The water at all three sites is generally unsuitable for drinking supplies due to naturally elevated concentrations of reduced iron and manganese in the groundwater and elevated concentrations of ammonium at many monitoring sites, particularly around the Turangi land treatment site and the Waimarino deep aquifer monitoring sites. Aeration followed by settling or filtration of the groundwater could significantly reduce the concentrations of iron and manganese. (4) Elevated concentrations of reduced iron and manganese are unlikely to affect the water quality of Lake Taupo as all reduced iron and manganese will be oxidised once the water reaches the lake and precipitate as oxyhydroxide minerals

  10. Probabilistic Seismic Hazard Analysis of Victoria, British Columbia, Canada: Considering an Active Leech River Fault

    Kukovica, J.; Molnar, S.; Ghofrani, H.

    2017-12-01

    The Leech River fault is situated on Vancouver Island near the city of Victoria, British Columbia, Canada. The 60km transpressional reverse fault zone runs east to west along the southern tip of Vancouver Island, dividing the lithologic units of Jurassic-Cretaceous Leech River Complex schists to the north and Eocene Metchosin Formation basalts to the south. This fault system poses a considerable hazard due to its proximity to Victoria and 3 major hydroelectric dams. The Canadian seismic hazard model for the 2015 National Building Code of Canada (NBCC) considered the fault system to be inactive. However, recent paleoseismic evidence suggests there to be at least 2 surface-rupturing events to have exceeded a moment magnitude (M) of 6.5 within the last 15,000 years (Morell et al. 2017). We perform a Probabilistic Seismic Hazard Analysis (PSHA) for the city of Victoria with consideration of the Leech River fault as an active source. A PSHA for Victoria which replicates the 2015 NBCC estimates is accomplished to calibrate our PSHA procedure. The same seismic source zones, magnitude recurrence parameters, and Ground Motion Prediction Equations (GMPEs) are used. We replicate the uniform hazard spectrum for a probability of exceedance of 2% in 50 years for a 500 km radial area around Victoria. An active Leech River fault zone is then added; known length and dip. We are determining magnitude recurrence parameters based on a Gutenberg-Richter relationship for the Leech River fault from various catalogues of the recorded seismicity (M 2-3) within the fault's vicinity and the proposed paleoseismic events. We seek to understand whether inclusion of an active Leech River fault source will significantly increase the probabilistic seismic hazard for Victoria. Morell et al. 2017. Quaternary rupture of a crustal fault beneath Victoria, British Columbia, Canada. GSA Today, 27, doi: 10.1130/GSATG291A.1

  11. Distribution and transportation of mercury from glacier to lake in the Qiangyong Glacier Basin, southern Tibetan Plateau, China.

    Sun, Shiwei; Kang, Shichang; Huang, Jie; Li, Chengding; Guo, Junming; Zhang, Qianggong; Sun, Xuejun; Tripathee, Lekhendra

    2016-06-01

    The Tibetan Plateau is home to the largest aggregate of glaciers outside the Polar Regions and is a source of fresh water to 1.4 billion people. Yet little is known about the transportation and cycling of Hg in high-elevation glacier basins on Tibetan Plateau. In this study, surface snow, glacier melting stream water and lake water samples were collected from the Qiangyong Glacier Basin. The spatiotemporal distribution and transportation of Hg from glacier to lake were investigated. Significant diurnal variations of dissolved Hg (DHg) concentrations were observed in the river water, with low concentrations in the morning (8:00am-14:00pm) and high concentrations in the afternoon (16:00pm-20:00pm). The DHg concentrations were exponentially correlated with runoff, which indicated that runoff was the dominant factor affecting DHg concentrations in the river water. Moreover, significant decreases of Hg were observed during transportation from glacier to lake. DHg adsorption onto particulates followed by the sedimentation of particulate-bound Hg (PHg) could be possible as an important Hg removal mechanism during the transportation process. Significant decreases in Hg concentrations were observed downstream of Xiao Qiangyong Lake, which indicated that the high-elevation lake system could significantly affect the distribution and transportation of Hg in the Qiangyong Glacier Basin. Copyright © 2016. Published by Elsevier B.V.

  12. [Distribution and Pollution Assessment of Nutrient and Heavy Metals in Surface Sediments from Lake Gehu in Southern Jiangsu Province, China].

    Xiong, Chun-hui; Zhagn, Rui-lei; Wu, Xiao-dong; Feng, Li-hui; Wang, Li-qing

    2016-03-15

    This study investigated the horizontal distribution characteristics of nutrients and heavy metals (Zn, As, Cr, Cu, Ni, Pb, Cd and Hg) in January, 2014, and assessed the potential ecological risk of Lake Gehu. It was found that the average contents of TN and TP were 2,207.94 and 708.62 mg · kg⁻¹ respectively. TN and TP contents of the sediments at the centre were significantly highei than those in the north, while the TN content in the south was also significantly higher than that in the north of Lake Gehu. The average contents of Zn, As, Cr, Cu, Ni, Pb, Cd, Hg were 766.59, 350.66, 307.98, 59.54, 122.67, 168.97, 2.34, 0.41 mg · kg⁻¹, respectively. The content of Cu at the centre was significantly higher than that in the north, and the Zn content at the centre was significantly greater than that in the south of Lake Gehu, however the difference in the content of other heavy metals at these three areas was not significant. Furthermore, the obvious correlation between elements and granularity was only found in the aspect of TP, Cu and Hg. The comprehensive pollution index (PI) indicated that the Lake Gehu was heavily polluted, especially the centre and south areas. The potential ecological risk index (RI) showed that Cd, As and Hg had caused serious pollution in Lake Gehu while the other heavy metals only induced slight or medium pollution. According to the contribution of Cd, As and Hg to RI, it was concluded that the sediments in Lake Gehu were at a serious potential ecological risk.

  13. Satellite lakes as reservoirs of fish species diversity

    Nkalubo, W.; Wandera, S.B.; Namulemo, G.

    2010-01-01

    Satellite lakes and rivers in the Victoria and Kyoga basins provide a sanctuary for endangered native fish species. The structural heterogeneity of macrophyte covering these lakes has made it possible for most of the biodiversity to be kept intact. The Kyoga minor lakes have the highest fish species diversity especially of the haplochromines. Most fish communities of these satellite lakes are composed of native species.

  14. Spiraal : uus Victoria & Alberti muuseum Londonis

    1998-01-01

    Daniel Libeskindi projekt Victoria & Alberti Muuseumi laiendamiseks on põhjustanud konservatiivsete londonlaste pahameele, kuid kutsunud esile ka hulgaliselt toetusavaldusi. Muuseumi uus osa (kokkuvarisemise piiril näiva ehitisena) peaks külastajaile avatama 2004. a.

  15. High-resolution OSL chronology of a sediment core from Lake Nam Co on the southern Tibetan Plateau: Comparison with radiocarbon dating

    Long, Hao; Shen, Ji; Haberzettl, Torsten; Fuchs, Markus; Frechen, Manfred; Wang, Junbo

    2013-04-01

    Numerous studies on lake sediment cores from the Tibetan Plateau aimed to reconstruct spatial and temporal changes of the late Glacial and Holocene monsoon variations, which are characterized by fluctuations in precipitation and expansion of monsoonal air masses across the Plateau. Accurate and reliable dating of lacustrine deposits is of crucial importance in both the reconstruction of palaeolake and palaeoclimate evolution and the understanding of the mechanisms for climate changes, especially abrupt changes of regional-hemispheric hydrological circulation. Radiocarbon dating is the most commonly used method for establishing chronologies of lake sediments. However, 14C dating of such sediments could be problematic due to the lack of organic matter or a reservoir effect, which appears common in radiocarbon dating of lacustrine sediments from the Tibetan Plateau. In this study, ca. 10.5 m long core (NC core) was retrieved from the water depth of 93 m at Nam Co Lake, which is the second largest saline lake in China, located on the southern Tibetan Plateau. For this core, high-resolution samples (23 samples) were obtained for optically stimulated luminescence (OSL) dating. Quartz of fine-grain (4-11 μm) fraction were extracted from this samples for OSL dating, which is compared with the 14C chronology of NC core based on accelerator mass spectrometry (AMS) dating of bulk organic matter of 22 samples. The sample from the top of NC core was dated to approximate zero age, indicating the sediments bleached well before deposition. Luminescence behaviors of the study samples further confirmed the robustness of OSL ages. Comparison between OSL and 14C ages suggested that: (1) two kinds of ages are in agreement within error from top to 1.8 m, (2) from 1.8 m to the base of NC core, the 14C ages show a general trend to ca. 4 ka higher ages than the OSL ages. Although 14C dating overestimate the ages from 1.8 m to base, they still show the general trend in sedimentation rate

  16. Activation of a small ephemeral lake in southern Jordan during the last full glacial period and its paleoclimatic implications

    Catlett, Gentry A.; Rech, Jason A.; Pigati, Jeffrey S.; Al Kuisi, Mustafa; Li, Shanying; Honke, Jeffrey S.

    2017-01-01

    Playas, or ephemeral lakes, are one of the most common depositional environments in arid and semiarid lands worldwide. Playa deposits, however, have mostly been avoided as paleoclimatic archives because they typically contain exceptionally low concentrations of organic material, making 14C dating difficult. Here, we describe a technique for concentrating

  17. Sample clean-up, enrichment and determination of s-triazine herbicides from southern ethiopian lakes supported using liquid membrane extraction

    Jan Åke Jönsson

    2000-06-01

    Full Text Available The liquid membrane extraction method has been employed for selectively extracting trace quantities of s-triazine herbicides in environmental waters collected from lakes Awassa, Chamo and Abbya, located in close proximity to the agricultural farms in Southern Ethiopia. In liquid membrane extraction, the uncharged triazine compounds from the flowing donor solution diffuse through a porous poly(tetrafluoroethylene (PTFE membrane, containing a water immiscible organic solvent. The s-triazine molecules are then irreversibly trapped in the stagnant acidic acceptor phase since they become protonated. Using both di-n-hexylether and n-undecane membrane solvents, s-traizine herbicides were extracted and low detection limits of about 1 ng/L have been obtained by extraction of three liters of sample solution spiked with 0.1 g/L of each triazine. Residues of atrazine and terbutryn ranging in concentration from 0.02 to 0.05 g/L have been successfully determined.

  18. Seasonal Variations in the Use of Profundal Habitat among Freshwater Fishes in Lake Norsjø, Southern Norway, and Subsequent Effects on Fish Mercury Concentrations

    Tom Robin Olk

    2016-11-01

    Full Text Available This study is based on monthly sampling of fish from grates mounted at an industrial water intake, located at a depth of 50 m in Lake Norsjø (Southern Norway during the year 2014, to investigate seasonal variations in the use of the profundal habitat and subsequent variations in total Hg-concentrations in profundal fish. Data on various fish present in a cold and dark hypolimnion of a large, deep, dimictic lake within the upper temperate zone of the Northern Hemisphere are rare. While predominant species such as A. charr (Salvelinus alpinus and E. smelt (Osmerus eperlanus were continuously present in this habitat, whitefish (Coregonus lavaretus occupied this habitat primarily during wintertime, while other common species like brown trout (Salmo trutta, perch (Perca fluviatilis and northern pike (Esox lucius were almost absent. Besides stomach analyses (diet and biometry, stable isotope analyses (δ15N and δ13C and total mercury (Tot-Hg analyses were carried out on the caught fish. The δ13C signature and stomach analyses revealed a combined profundal-pelagic diet for all three species, A. charr with the most profundal-based diet. Length was the strongest predictor for Hg in whitefish and A. charr, while age was the strongest explanatory variable for Hg in E. smelt. A. charr was the only species exhibiting seasonal variation in Hg, highest during winter and spring.

  19. Distribution of 127Cs and 90Sr in southern part of Pyajyanne lake and in its catchment area

    Saksen, R.; Rantavaara, A.; Yaakkola, T.

    1998-01-01

    Slight increase in 90 Sr content from river discharges was observed in the near-the-surface layers og the Asikkalanselk bay of the Pyajanne lake in the years directly following the Chernobyl accident; later it remained almost runchanged, whereas 137 Cs concentration is decreasing. 90 Sr was identified in the bottoms at greater depth than 137 Cs. Radionuclides transport by small rivers from water catchment zones to Asikkalanselsk was studied in 1995-1997. It is established that greater part of 137 Cs is leached into the surface waters from swamped areas. The swamped soils are also characterized by higher degree of 90 Sr washing out. The role of 137 Cs and 90 Sr surface discharges from catchment as compared to radionuclide exchange with other parts of the lake, containing greater water volumes

  20. A 12,000-Year-Long, Annually-Resolved Varve Record Spanning the Last Interglacial from Lake Bosumtwi, Southern Ghana

    McKay, N.; Overpeck, J. T.; Shanahan, T. M.; Peck, J. A.; Heil, C. W.; King, J. W.; Scholz, C. A.

    2012-12-01

    The impact of continued global warming on the likelihood of severe drought in sub-Saharan West Africa remains uncertain, as climate models generally do not simulate realistic climate dynamics in the region and have inconsistent projections for the future. The Last Interglacial period (LIG), occurring between 128 and 116 thousand years ago, is a partial analog for future warming because at its peak, global temperatures were slightly higher, and this warming was accentuated in Northern Hemisphere terrestrial summer temperatures. Here we present a new, annually-resolved, 12,100-year-long varve record for the LIG from Lake Bosumtwi in southern Ghana (6.5°N, 1.4°W). The abundance of terrigenous elements in the sediment, varve thickness, and the isotope geochemistry and mineralogy of authigenic carbonates in the sediment were used to infer changes in lake level. The varve chronology, varve thickness and elemental abundance records were developed with a new ensemble approach that allows for a more robust determination of uncertainty in the record. The new records reveal a dynamic history of hydrologic variability during the LIG. The LIG lake highstand was lower and shorter-lived than the the prolonged highstand in the early Holocene, and unlike the Holocene, the lake never overflowed during LIG. The overall drier conditions during the LIG are most likely driven by amplified precessional forcing during the interval, resulting in a northward shift in the rainbelt. The LIG, like the Holocene, had two distinct millennial-scale moist intervals, from 125 - 123 and 121 - 120 ka. In both the LIG and the Holocene, these peaks occurred during times of precession-driven insolation maxima in July and October, corresponding to the two rainy seasons in the modern climatology. This suggests that, at least during interglacials, prolonged wet conditions occur at the lake when rainy season insolation is highest. Over the course of the LIG, lake level generally tracked sea surface

  1. Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards

    A. Simonneau

    2013-03-01

    Full Text Available High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and riverbed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments have been finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events (SEs: light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography of the organic matter present in soil, riverbed and lacustrine samples together with lake sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass-movements triggered by historical and pre-historical regional earthquakes dated to AD 2005, AD 1891, AD 1045 and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11 495 cal. yr BP. Dark-coloured SEs develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and lignocellulosic debris and are interpreted as resulting from intense hyperpycnal flood event. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 5 mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting from the combination of heavy rainfall and snowmelt. The

  2. A Fragment of Ophiolite Assemblage of Kasargi Lake Area: East-Urals Megazone, Northern Part of the Southern Urals

    D. E. Saveliev

    2014-03-01

    Full Text Available The results of study of rocks of ophiolite assemblage exposed on the east coast of Kasargi Lake are presented. The ophiolite assemblage is formed with the serpentinised ultramafic rocks of dunite-harzburgite association, which are residual and the shlirenbanded gabbros with a number of later dikes of diabases and porphiritic gabbros. The chemical content of mafic and ultramafic rocks of Kasargi massif shows that they are likely the equivalent rocks encountered within the backarc spreading ridges.

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

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

    2012-10-01

    Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  4. Hydrogeological behaviour of the Fuente-de-Piedra playa lake and tectonic origin of its basin (Malaga, southern Spain)

    Rodriguez-Rodriguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio

    2016-12-01

    Changes in the quantity of groundwater input due to water extraction for irrigation and urban supply has modified the water balance in the Fuente de Piedra playa lake. We have analysed the hydrogeology of the playa-lake system and developed a water-level model by means of a simple long-term water balance and piezometric analysis. In addition, a tectonic model is proposed to explain the endorheic basin development that led to the formation of the playa. Upright folds developed since the late Miocene and density-driven subsidence favoured the setting-up of and endorheic system located between the Atlantic and the Mediterranean basins in the Quaternary. The underlying low permeability rocks beneath the playa form a very stable aquitard with highly saline groundwater that prevents groundwater recharge of the lake into the aquitard. The hydrological modelling allowed us to simulate the evolution of the wáter level under a scenario of unaltered conditions during a 13-year period, showing that the percentage of days with dry conditions varies from 24.8% of the time under altered conditions to 14.9% as far as an unaltered scenario is concerned.

  5. Metal concentrations in zebra mussels and sediments from embayments and riverine environments of eastern Lake Erie, southern Lake Ontario, and the Niagara River.

    Lowe, T P; Day, D D

    2002-10-01

    Concentrations of 14 metals were studied in the soft tissues of zebra mussels ( Dreissena polymorpha) and sediments from 16 Great Lakes embayments and riverine environments. Samples were collected in 1993 and 1994 during the early and late autumn period when the body mass of mussels is least affected by reproductive activities. There was a significant difference in geometric mean concentrations of all metals except Cu in mussels sampled from different sites, and there was a significant difference in the geometric mean concentrations of all metals but Cd, Mn, and Zn between years. The higher metal concentrations in mussels from this study were generally similar to those in mussels from contaminated European and U.S. locations, and those with lower concentrations were similar to those from uncontaminated European and U.S. locations. Geometric mean sediment concentrations of all metals differed significantly among sites. Sediment concentrations of metals from some sites were above EPA guidelines for moderately polluted harbor sediments. Sites where zebra mussels had higher concentrations of Al, Cr, and V tended to be the same sites as those where sediment concentrations of these metals were also higher. However, there was not a significant statistical relationship between concentrations of metals in zebra mussels and sediments, except for Mg.

  6. Phytoplankton productivity in newly dug fish ponds within Lake ...

    The declining Lake Victoria fisheries resource led to a growing recognition of aquaculture as a source of livelihood to riparian communities. Finger ponds speculated to naturally stock fish during flooding and retain them during dry seasons were introduced within the lake's wetlands. In order to develop a

  7. Evaluating MERIS-Based Aquatic Vegetation Mapping in Lake Victoria

    Cheruiyot, E.K.; Mito, C.; Menenti, M.; Gorte, B.G.H.; Koenders, R.; Akdim, N.

    2014-01-01

    Delineation of aquatic plants and estimation of its surface extent are crucial to the efficient control of its proliferation, and this information can be derived accurately with fine resolution remote sensing products. However, small swath and low observation frequency associated with them may be

  8. Governance and Welfare of Fishing Communities of Lake Victoria ...

    These include the introduction of a co-management system of Beach Management units (BMUs) which are elected by the fishing communities and will work with the ... Educational standards remain low and many communities lack proper sanitation, and are therefore at risk of disease, while most basic facilities such as ...

  9. Valuation of Environmental Assets in the Lake Victoria basin.

    Kulindwa, K.A.A.

    2006-01-01

    Chapter 8 of Agenda 21, the programme of action by the United Nations, an outcome of the earth summit in Rio de Janeiro in 1992, advocates for “Making effective use of economic instruments and market and other incentives” in integrating environment and development in decision making. In order to achieve Sustainable Development (SD), economic, social justice and environmental conservation have to be considered simultaneously in an integrated manner. The environmental dimension requires knowled...

  10. Soil erosion and sedimentation rates in a small eutrophic lake in southern Chile estimated by 210Pb isotope analysis

    Cisternas, M.; Urrutia, R.; Araneda, A.; Debels, P.; Rios, F.

    1999-01-01

    The purpose of this research is to study the effects of historical land use patterns on soil erosion within the San Pedro Lake watershed (Concepcion, VIII Region, Chile). To this end, a geochronological reconstruction of the last 50 years was accomplished by 210 Pb isotope and photo-interpretation analysis through the use of GIS. The erosion rate has varied from 0.40 t ha -1 y -1 in 1955 to 0.86 t ha -1 y -1 in 1994. The decrease in native forest was closely coupled with the increase in exotic forestry. The Total Change, meaning the land use change without considering each typology, shows a constant trend indicating a greater degree of anthropogenic intervention. As opposed to the expected, there is no relationship between land use typologies and erosion rates, however it is possible to recognise some degree of dependency between Total Change and erosion values. It is concluded that over the last 50 years the soil erosion processes in the San Pedro Lake watershed may have been more regulated more by land use changes than by land use typologies themselves. (author)

  11. Coal Corporation of Victoria annual report 1986

    1986-01-01

    Information is presented on operations, strategic planning, brown coal production and finance. Divisional reports are presented for the following divisions of the Coal Corporation of Victoria: marketing, technical marketing and special projects, research and development, and corporate services. The activities of the technical marketing and special projects division are discussed under the following headings: the coal for industry programme, the Brown Coal Liquefaction (Victoria) Pty. Ltd. project, dried brown coal activities, and resource development planning and policy activities. The corporation is currently conducting research into the following areas: ion exchange materials, activated carbons, and horticultural and agricultural applications of brown coal.

  12. Insights into hydroclimatic variability of Southern California since 125 ka, from multi-proxy analyses of alpine lakes

    Glover, K. C.; MacDonald, G. M.; Kirby, M.

    2016-12-01

    Hydroclimatic variability is especially important in California, a water-stressed and increasingly populous region. We assess the range of past hydroclimatic sensitivity and variability in the San Bernardino Mountains of Southern California based on 125 ka of lacustrine sediment records. Geochemistry, charcoal and pollen highlight periods of sustained moisture, aridity and sudden variability driven by orbital and oceanic variations. Marine Isotope Stage 3 (MIS 3) is one such period of greater moisture availability that lasted c. 30 kyr, with smaller-scale perturbations likely reflect North Atlantic Dansgaard-Oeschgar events. Past glacial periods, MIS 4 and MIS 2, display high-amplitude changes. These include periods of reduced forest cover that span millennia, indicating long-lasting aridity. Rapid forest expansion also occurs, marking sudden shifts towards wet conditions. Fire regimes have also changed in tandem with hydroclimate and vegetation. Higher-resolution analysis of the past 10 ka shows that Southern California hydroclimate was broadly similar to other regions of the Southwest and Great Basin, including an orbital and oceanic-driven wet Early Holocene, dry Mid-Holocene, and highly variable Late Holocene. Shorter-term pluvial conditions occur throughout the Holocene, with episodic moisture likely derived from a Pacific source.

  13. Seabed surveys of Victoria harbour, Mahe, Seychelles

    Hashimi, N.H.; Wagle, B.G.

    The seabed surveys in the Victoria Harbour, Mahe, Seychelles shows that the prominent feature is the navigational channel aligned in the northeast-southwest direction with a width varying from 300 to 450m. The depth in the channel ranges from 14...

  14. Understanding the groundwater dynamics in the Southern Rift Valley Lakes Basin (Ethiopia). Multivariate statistical analysis method, oxygen (δ 18O) and deuterium (δ 2H)

    Girum Admasu Nadew; Zebene Lakew Tefera

    2013-01-01

    Multivariate statistical analysis is very important to classify waters of different hydrochemical groups. Statistical techniques, such as cluster analysis, can provide a powerful tool for analyzing water chemistry data. This method is used to test water quality data and determine if samples can be grouped into distinct populations that may be significant in the geologic context, as well as from a statistical point of view. Multivariate statistical analysis method is applied to the geochemical data in combination with δ 18 O and δ 2 H isotopes with the objective to understand the dynamics of groundwater using hierarchical clustering and isotope analyses. The geochemical and isotope data of the central and southern rift valley lakes have been collected and analyzed from different works. Isotope analysis shows that most springs and boreholes are recharged by July and August rainfalls. The different hydrochemical groups that resulted from the multivariate analysis are described and correlated with the geology of the area and whether it has any interaction with a system or not. (author)

  15. Retrospective assessment of macrophytic communities in southern Lake Garda (Italy from in situ and MIVIS (Multispectral Infrared and Visible Imaging Spectrometer data

    Claudia Giardino

    2012-01-01

    Full Text Available In situ and hyperspectral MIVIS (Multispectral Infrared and Visible Imaging Spectrometer images acquired over a period of 13 years are used to assess changes in macrophyte colonization patterns in the coastal zones of the Sirmione Peninsula in the southern part of Lake Garda (Italy. In situ data (abundance, cover density and diversity of macrophyte communities and MIVIS-derived maps of colonized substrates are analyzed by considering the variability of the main hydrological and physicochemical variables in order to indicate the main factors that explain the spatiotemporal variability of macrophyte communities. The results show a considerable modification in terms of macrophyte structural complexity and colonized areas. Almost 98% of macrophyte meadows (in particular communities with a density of over 70% are lost and subsequently replaced by moderate to extremely rare communities with density from 10% to 40%. Well-established submerged macrophytes are replaced by de-structured communities characterized by moderate to scarce density: on average lower than 30%. The study indicates that macrophyte distribution along the littoral zone of the Sirmione Peninsula is certainly linked to water transparency and water level fluctuation. The results also indicate that the worsening of eutrophication may be associated with the gradual disappearance of macrophyte meadows, but may also be accelerated by herbivorous aquatic birds grazing there. Lastly, the increasing frequency and number of catamaran tours could be considered a threat for the stability of these valuable communities.

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

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

    2014-01-01

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

  17. Hemofilie onder die nasate van koningin Victoria

    Francois P. Retief

    2013-03-01

    Full Text Available Hierdie studie bespreek die uitwerking van die sogenaamde Victoriaanse hemofilie op Europese koningshuise gedurende die negentiende en twintigste eeu. Hemofilie as molekulêre defek word verduidelik en die kliniese beeld van die siekte word aangedui. ’n Bespreking van toepaslike terapeutiese ingrepe volg. Dan word ’n historiese oorsig verskaf van die verspreiding van Victoriaanse hemofilie vanaf koningin Victoria (Britse monarg, 1837–1901 via sommige van haar dogters na ander lede van die Britse koningshuis en ook na die Duitse, Russiese en Spaanse koningshuise. Elf bevestigde gevalle van hemofilie onder lede van koningin Victoria se nageslag word vermeld, asook drie ander moontlike gevalle van die siekte. Die effek van hemofilie op die verloop van die geskiedenis word ook ondersoek.Haemophilia amongst the descendants of Queen Victoria. This study discusses the impact of ‘Victorian haemophilia’ on the royal houses of Europe during the 19th and 20th centuries. Haemophilia as a molecular defect is explained and the clinical picture of the condition is indicated. Applicable therapeutic interventions also receive attention. Next, an historical review is provided of how ‘Victorian haemophilia’ spread from Queen Victoria (British monarch, 1837–1901 via some of her daughters to other members of the British royal family and also to the royal houses of Germany, Russia and Spain. Eleven confirmed cases of haemophilia amongst the descendants of Queen Victoria are mentioned, as well as three other possible cases. The effect of haemophilia on the course of history is also investigated.

  18. Effects of natural banks of free-floating plants on zooplankton community in a shallow subtropical lake in Southern Brazil

    Vanessa Gazulha

    2011-08-01

    Full Text Available The aim of this study was to test the effects of natural free-floating plants on zooplankton distribution in a shallow subtropical lake. First, the hypothesis that free-floating plants have an effect on physico-chemicals, leading to a decrease on nutrient availability and influencing the phytoplankton biomass and zooplankton community was tested. Second, the hypothesis that free-floating plants act as a refuge for zooplankton was tested. Three microhabitats were selected: free-floating plants, littoral area and open water. Results demonstrated that the effects of different microhabitats on phytoplankton biomass and physico-chemicals were not significant, indicating a weak influence of the plants. Zooplankton densities were higher in free-floating plants and littoral area, although the effect of microhabitats was weak for most of the predominant genera. The absence of free-floating plant effects on phytoplankton and physico-chemicals showed that it was not a factor influencing the microcrustacean distribution in the microhabitats. Low differences in densities of zooplankton among microhabitats and low abundance of large-bodied cladocerans led to reject the hypothesis that free-floating plants act as a refuge for zooplankton.

  19. Zebra mussels (Dreissena polymorpha) as a biomonitor of trace elements along the southern shoreline of Lake Michigan.

    Shoults-Wilson, W Aaron; Elsayed, Norhan; Leckrone, Kristen; Unrine, Jason

    2015-02-01

    The invasive zebra mussel (Dreissena polymorpha) has become an accepted biomonitor organism for trace elements, but it has yet to be studied along the Lake Michigan shoreline. Likewise, the relationships between tissue concentrations of elements, organism size, and sediment concentrations of elements have not been fully explained. The present study found that a variety of allometric variables such as length, dry tissue mass, shell mass, organism condition indices, and shell thickness index were useful in explaining intrasite variability in elemental concentrations. The flesh condition index (grams of tissue dry mass per gram of shell mass) explained variability at the most sites for most elements. Once allometric intrasite variability was taken into account, additional significant differences were found between sites, although the net effect was small. Significant positive relationships between sediment and tissue concentrations were found for Pb and Zn, with a significant negative relationship for Cd. It was also found that Cu and Zn concentrations in tissues increased significantly along the shoreline in the southeasterly direction, whereas Hg increased in a northwesterly direction. Opportunistic sampling found that zebra mussels accumulate significantly higher concentrations of nearly all elements analyzed compared to Asian clams (Corbicula fluminea) at the same site. The present study demonstrates the need to fully explain natural sources of variability before using biomonitors to explain spatial distributions of trace elements. © 2014 SETAC.

  20. A review of the influence of biogeography, riverine linkages, and marine connectivity on fish assemblages in evolving lagoons and lakes of coastal southern Africa

    Whitfield, AK

    2017-09-01

    Full Text Available lakes), elements of the marine fish assemblage have persisted, especially the presence of facultative catadromous species. Freshwater fish diversity in coastal lakes and lagoons is a function of historical and present biogeography and salinity. From a...

  1. Quaternary lacustrine braid deltas on Lake General Carrera in southern Chile Deltas entrelazados lacustres del Cuaternario en el lago General Carrera, sur de Chile

    C. Mike Bell

    2009-01-01

    Full Text Available A series of Quaternary lacustrine braid deltas on the shores of Lake General Carrera in southern Chile formed as a result of falls in lake level. Each delta comprises two components, the delta fan and the beach embayment, each in turn comprising an onshore subaerial and an offshore subaqueous element. The delta fans have a classic Gilbert form with a braided delta top and a steeply inclined delta front. Adjacent to the fans are concave beach embayments that formed parallel with the deltas as they prograded into the lake. The delta sediments consist predominantly of matrix- and clast-supported gravéis to a total composite thickness exceeding 400 m. The depositional environments are dominated by ephemeral river flooding and by storm-driven waves. Beach sediment is sorted, rounded, winnowed and transported alongshore by waves to fill the beach embayment with ridges of very well sorted and well-rounded gravel. A gently-dipping shoreface platform occurs up to 100 m offshore between the beach and the brink point. From the brink point, in water depth of about 8 m, sediment cascades down the steep delta front slope to form long foresets extending to the lake floor. The sedimentary successions therefore wedge in the opposite direction from those of tectonically controlled basin margins where fan growth keeps pace with basin subsidence.Una serie de deltas entrelazados lacustres, pertenecientes al Cuaternario, ubicados en las costas del lago General Carrera, en el sur de Chile, se formaron como resultado de caídas en el nivel del lago. Cada delta consta de dos componentes: el abanico deltaico y la zona de embahiamiento. Cada uno de ellos tiene, a su vez, un elemento subaéreo costero y un elemento subacuático. Los abanicos deltaicos tienen una forma Gilbert clásica con una parte superior de ríos entrelazados y un frente deltaico empinado. Adyacente a los abanicos aluviales existen bahías cóncavas de playa que se formaron de manera paralela a los

  2. Late-Holocene Environmental Reconstruction and Depositional History from a Taxodium Swamp near Lake Pontchartrain in Southern Louisiana

    Ryu, J.; Bianchette, T. A.; Liu, K. B.; Yao, Q.; Maiti, K.

    2017-12-01

    The hydrological and environmental history of estuarine wetlands in Louisiana is not well-documented. To better understand the depositional processes in coastal wetlands, this study aims to reconstruct the environmental changes and document the occurrence of event deposits found in a bald cypress (Taxodium distichum) swamp approximately 800 m west of Lake Pontchartrain, a site susceptible to wind-generated storm surges as well as inundation from other fluvial and lacustrine processes. 210Pb analysis of a 59 cm sediment core (WMA-1) suggests that it has a sedimentation rate of 0.39 cm/year, consistent with the detection of a 137Cs peak at 17 cm from the core top. Results of sedimentological, geochemical, and palynological analyses reveal that the core contains two distinct sediment facies: an organic-rich dark brown peat unit from 0 to 29 cm containing low concentrations of terrestrial elements (e.g., Ti, Fe, and K), and a clay unit from 30 to 59 cm with elevated concentrations of most elements. Two thin clay layers, at 3-5 cm and 14-19 cm, embedded in the upper peat section are probably attributed to two recent storm events, Hurricane Isaac (2012) and Hurricane Gustav (2008), because both hurricanes caused heavy rain and significant storm-surge flooding at the study site. The pollen assemblage in the clay section is dominated by TCT (mainly Taxodium), but it is replaced by Salix and wetland herbaceous taxa in the overlying peat section. The multi-proxy data suggest that a cypress swamp has been present at the site for at least several hundred years but Taxodium was being replaced by willow (Salix) and other bottomland hardwood trees and wetland herbs as the water level dropped. Human activities may have been an important factor causing the hydrological and ecological changes at the site during the past century.

  3. 100 Years of Accumulated Deformation at Depth Observed in the Elizabeth Lake Tunnel, Southern San Andreas Fault

    Telling, J. W.; Tayyebi, A.; Hudnut, K. W.; Davis, C. A.; Glennie, C. L.

    2017-12-01

    The Elizabeth Lake Tunnel was completed in 1911 to convey water from the Owens Valley to Los Angeles, CA. The tunnel is approximately 8-km long and crosses the San Andreas Fault (SAF) at a depth of 90 m below the surface, measured near the tunnel mid-point. If present, a tectonic signal recorded by warping or offset of this tunnel could provide an opportunity to examine the deformation at depth in this location during the 100 years since the tunnel was constructed. A temporary closure of the tunnel for inspection and repair allowed the entire 8-km length to be surveyed using terrestrial laser scanning, providing a complete high-resolution 3D model of the tunnel. Since a high-resolution survey of the tunnel after its construction is not available for comparison, we assume that the tunnel was originally straight; this assumption is substantiated by records that indicate that the two halves of the tunnel, dug from opposite ends, met within 2.9 cm in the XY-plane and 1.6 cm in the Z-direction, at an off-fault location. Our results show 20 cm of right-lateral horizontal deformation near the estimated location of the tunnel's intersection with SAF, which agrees with the SAF sense of motion. The zone of deviation is approximately 300 m south of the SAF surface trace, and is about 350 m south of where the two tunneling crews met. This observed offset is consistent with either steady-state creep of about 2 mm/yr or possibly residual afterslip following the 1857 earthquake (that may be negligible at present). The full tectonic strain accumulation at this location would be five to ten times higher than observed, so clearly the observed deformation is only part of the expected full tectonic signal. In addition to the 20 cm short-wavelength deflection, we are examining for possible subtle longer wavelength deformation of the tunnel. The lidar model also shows significantly higher density of apparent cracking in the tunnel walls near this intercept point.

  4. Mathematical Problems in Biology : Victoria Conference

    1974-01-01

    A conference on "Some Mathematical Problems in Biology" was held at the University of Victoria, Victoria, B. C. , Canada, from May 7 - 10, 1973. The participants and invited speakers were mathematicians interested in problems of a biological nature, and scientists actively engaged in developing mathematical models in biological fields. One aim of the conference was to attempt to assess what the recent rapid growth of mathematical interaction with the biosciences has accomplished and may accomplish in the near future. The conference also aimed to expose the problems of communication bet~",een mathematicians and biological scientists, and in doing so to stimulate the interchange of ideas. It was recognised that the topic spans an enormous breadth, and little attempt was made to balance the very diverse areas. Widespread active interest was shown in the conference, and just over one hundred people registered. The varied departments and institutions across North America from which the participants came made it bo...

  5. Chemistry models in the Victoria code

    Grimley, A.J. III

    1988-01-01

    The VICTORIA Computer code consists of the fission product release and chemistry models for the MELPROG severe accident analysis code. The chemistry models in VICTORIA are used to treat multi-phase interactions in four separate physical regions: fuel grains, gap/open porosity/clad, coolant/aerosols, and structure surfaces. The physical and chemical environment of each region is very different from the others and different models are required for each. The common thread in the modelling is the use of a chemical equilibrium assumption. The validity of this assumption along with a description of the various physical constraints applicable to each region will be discussed. The models that result from the assumptions and constraints will be presented along with samples of calculations in each region

  6. Queen Victoria, her physicians, and her cataracts.

    Ravin, J G

    1994-01-01

    Decreasing vision due to cataracts became a significant problem for Queen Victoria toward the end of the 19th century. Her personal physician, Sir James Reid, obtained consultations with two eminent British ophthalmologists, George Lawson and Edward Nettleship. The Queen was not satisfied, and requested an opinion from the German professor Hermann Pagenstecher. All the doctors agreed on the diagnosis, but the Queen never underwent surgery.

  7. Pancam Peek into 'Victoria Crater' (Stereo)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA08776 [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA08776 A drive of about 60 meters (about 200 feet) on the 943rd Martian day, or sol, of Opportunity's exploration of Mars' Meridiani Planum region (Sept. 18, 2006) brought the NASA rover to within about 50 meters (about 160 feet) of the rim of 'Victoria Crater.' This crater has been the mission's long-term destination for the past 21 Earth months. Opportunity reached a location from which the cameras on top of the rover's mast could begin to see into the interior of Victoria. This stereo anaglyph was made from frames taken on sol 943 by the panoramic camera (Pancam) to offer a three-dimensional view when seen through red-blue glasses. It shows the upper portion of interior crater walls facing toward Opportunity from up to about 850 meters (half a mile) away. The amount of vertical relief visible at the top of the interior walls from this angle is about 15 meters (about 50 feet). The exposures were taken through a Pancam filter selecting wavelengths centered on 750 nanometers. Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and therefore, potentially preserving several times the historical record.

  8. VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan

    2014-06-01

    1472G. VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan and Preliminary Results © Her Majesty the Queen in Right of...19 th International Command and Control Research and Technology Symposium Title: VICTORIA Class Submarine Human-in-the-Loop...TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan 5a. CONTRACT

  9. Dragon Lake, Siberia

    2002-01-01

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

  10. climate change and lake water resourcesin sub-saharan africa: case ...

    user

    STUDY OF LAKE CHAD AND LAKE VICTORIA ... contribution to agriculture and socio-economic development of the region were ... many developing countries, current levels in water use .... 2050 and will become increasingly urban by implication. ... 4.1 Justification of Selected Case Studies ..... Orstom, Paris France. 1996.

  11. Ecology of playa lakes

    Haukos, David A.; Smith, Loren M.

    1992-01-01

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

  12. Dam safety management in Victoria (Australia)

    Adem, J.

    1996-01-01

    The Victoria state government's decision to make dam owners accountable for safety and upkeep of their dams was reported. To give effect to this decision a series of guidelines have been developed which outline the required activities and skills to ensure that dams are properly managed within a framework of 'light-handed' regulation. The guidelines are also intended to ensure that dam management becomes an integral part of the business decision making process, not just a set of prescribed technical procedures. Details of the direction being taken and the proposed controls to ensure compliance with national and international standards were described. 4 refs., 2 figs

  13. Coal Corporation of Victoria strategic plan

    1987-01-01

    The Coal Corporation has been established by the Victorian Parliament to plan for and to manage the responsible utilisation of the brown coal resource (Victoria's most abundant fossil resource) in order to underpin economic growth and job creation. For each of 5 issues, the Strategic Plan outlines the current situation, reviews recent factors which have affected or may affect the situation and outlines the goals, strategies and targets which have been set for the period 1985/1989. In each case, the achievements to date are also outlined. The issues addressed are: project development, marketing, resource planning and inter corporate relations, organisation of the Corporation, and finance.

  14. Similar levels of diversity and population Structure in superflock and ...

    superflock cichlid fishes from Lake Victoria, Africa. ... Tropical Freshwater Biology ... We use DNA microsatellite loci to estimate neutral genetic diversity and the level of gene flow among populations of two cichlid species from southern Lake Victoria, ...

  15. Requirements for VICTORIA Class Fire Control System: Contact Management Function

    2014-07-01

    Requirements for VICTORIA Class Fire Control System Contact Management Function Tab Lamoureux CAE Integrated Enterprise Solutions...Contract Report DRDC-RDDC-2014-C190 July 2014 © Her Majesty the Queen in Right of Canada, as represented by the...i Abstract …….. The VICTORIA Class Submarines (VCS) are subject to a continuing program of technical upgrades. One such program is

  16. Youth suicide in Victoria: a retrospective study.

    Krupinski, J; Tiller, J W; Burrows, G D; Hallenstein, H

    1994-02-07

    To determine the trends in youth suicide in Victoria and Australia as a whole, and their relation to youth unemployment. We used Australian Bureau of Statistics data to analyse suicide trends between 1907 and 1990 in young people aged 15-24 years and made an in-depth study of youth suicides between 1980 and 1990, for which computerised data are available. There has been a steady increase in youth suicide both in Victoria and Australia as a whole since 1960 in males but not females. There were significant differences in age, sex and area of residence in both the rate and the method of suicide. The increase in youth suicide was not associated with the rise in unemployment. Male (not female) suicide rates were higher in non-metropolitan areas and areas of high youth unemployment. The reasons for the increase in youth suicide remain obscure. There is a need for a prospective in-depth study to determine factors in the aetiology of youth suicide, with particular reference to possible areas for prevention.

  17. Direct and indirect effects of vertical mixing, nutrients and ultraviolet radiation on the bacterioplankton metabolism in high-mountain lakes from southern Europe

    Durán, C.; Medina-Sánchez, J. M.; Herrera, G.; Villar-Argaiz, M.; Villafañe, V. E.; Helbling, E. W.; Carrillo, P.

    2014-05-01

    As a consequence of global change, modifications in the interaction among abiotic stressors on aquatic ecosystems have been predicted. Among other factors, UVR transparency, nutrient inputs and shallower epilimnetic layers could alter the trophic links in the microbial food web. Currently, there are some evidences of higher sensitiveness of aquatic microbial organisms to UVR in opaque lakes. Our aim was to assess the interactive direct and indirect effects of UVR (through the excretion of organic carbon - EOC - by algae), mixing regime and nutrient input on bacterial metabolism. We performed in situ short-term experiments under the following treatments: full sunlight (UVR + PAR, >280 nm) vs. UVR exclusion (PAR only, >400 nm); ambient vs. nutrient addition (phosphorus (P; 30 μg PL-1) and nitrogen (N; up to final N : P molar ratio of 31)); and static vs. mixed regime. The experiments were conducted in three high-mountain lakes of Spain: Enol [LE], Las Yeguas [LY] and La Caldera [LC] which had contrasting UVR transparency characteristics (opaque (LE) vs. clear lakes (LY and LC)). Under ambient nutrient conditions and static regimes, UVR exerted a stimulatory effect on heterotrophic bacterial production (HBP) in the opaque lake but not in the clear ones. Under UVR, vertical mixing and nutrient addition HBP values were lower than under the static and ambient nutrient conditions, and the stimulatory effect that UVR exerted on HBP in the opaque lake disappeared. By contrast, vertical mixing and nutrient addition increased HBP values in the clear lakes, highlighting for a photoinhibitory effect of UVR on HBP. Mixed regime and nutrient addition resulted in negative effects of UVR on HBP more in the opaque than in the clear lakes. Moreover, in the opaque lake, bacterial respiration (BR) increased and EOC did not support the bacterial carbon demand (BCD). In contrast, bacterial metabolic costs did not increase in the clear lakes and the increased nutrient availability even

  18. 76 FR 23276 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

    2011-04-26

    ... Interagency Partnership on the Lake Tahoe Region and other matters raised by the Secretary. DATES: The meeting... preliminary recommendation of Lake Tahoe Southern Nevada Public Land Management Act (SNPLMA) Round 12 capital... Lake Tahoe SNPLMA Round 12 capital projects and science themes, and 3) public comment. All Lake Tahoe...

  19. The chemical and biological response of two remote mountain lakes in the Southern Central Alps (Italy) to twenty years of changing physical and chemical climate

    Andrea LAMI; Pierluigi CAMMARANO; Michele ARMIRAGLIO; Pierisa PANZANI; Roberta BETTINETTI; Alessandra PUGNETTI; Anna M. NOCENTINI; Gabriele A. TARTARI; Simona MUSAZZI; Giuseppe MORABITO; Angela BOGGERO; Marina MANCA; Michela ROGORA; Rosario MOSELLO; Aldo MARCHETTO

    2004-01-01

    Two small high mountain lakes in the Alps were monitored in 1984-2003 to follow their response to changes in human impact, such as deposition of atmospheric pollutants, fish stocking and climate change. The results were compared to occasional samplings performed in the 1940s, and to the remains found in sediment cores. When monitoring started, the most acid-sensitive of them, Lake Paione Superiore, was acidified, with evident effects in its flora and fauna: benthic diatoms assemblage was shif...

  20. The chemical and biological response of two remote mountain lakes in the Southern Central Alps (Italy to twenty years of changing physical and chemical climate

    Andrea LAMI

    2004-02-01

    Full Text Available Two small high mountain lakes in the Alps were monitored in 1984-2003 to follow their response to changes in human impact, such as deposition of atmospheric pollutants, fish stocking and climate change. The results were compared to occasional samplings performed in the 1940s, and to the remains found in sediment cores. When monitoring started, the most acid-sensitive of them, Lake Paione Superiore, was acidified, with evident effects in its flora and fauna: benthic diatoms assemblage was shifted towards acidophilous species, and zooplankton lost the dominant species, Arctodiaptomus alpinus. Palaeolimnological studies outlined that lake acidification paralleled the increasing input of long-range transported industrial pollutants, traced by spherical carbonaceous particles. On the contrary, the biota of Lake Paione Inferiore appeared to be mainly affected by fish stocking. In the last twenty years, decrease in acid load from the atmosphere led to an improvement in lake water quality, with an increase in both pH and alkalinity. First signs of biological recovery were identified, such as change in diatom flora and appearance of sensitive species among benthic insects. However, climate change and episodic deposition of Saharan dust were important driving factors controlling lake water chemistry. Further monitoring to assess the effects of climate change and of the increasing load of nitrogen and other pollutants is recommended.

  1. Prokaryotic Abundance and Activity in Permafrost of the Northern Victoria Land and Upper Victoria Valley (Antarctica).

    La Ferla, Rosabruna; Azzaro, Maurizio; Michaud, Luigi; Caruso, Gabriella; Lo Giudice, Angelina; Paranhos, Rodolfo; Cabral, Anderson S; Conte, Antonella; Cosenza, Alessandro; Maimone, Giovanna; Papale, Maria; Rappazzo, Alessandro Ciro; Guglielmin, Mauro

    2017-08-01

    Victoria Land permafrost harbours a potentially large pool of cold-affected microorganisms whose metabolic potential still remains underestimated. Three cores (BC-1, BC-2 and BC-3) drilled at different depths in Boulder Clay (Northern Victoria Land) and one sample (DY) collected from a core in the Dry Valleys (Upper Victoria Valley) were analysed to assess the prokaryotic abundance, viability, physiological profiles and potential metabolic rates. The cores drilled at Boulder Clay were a template of different ecological conditions (different temperature regime, ice content, exchanges with atmosphere and with liquid water) in the same small basin while the Dry Valleys site was very similar to BC-2 conditions but with a complete different geological history and ground ice type. Image analysis was adopted to determine cell abundance, size and shape as well as to quantify the potential viable and respiring cells by live/dead and 5-cyano-2,3-ditolyl-tetrazolium chloride staining, respectively. Subpopulation recognition by apparent nucleic acid contents was obtained by flow cytometry. Moreover, the physiological profiles at community level by Biolog-Ecoplate™ as well as the ectoenzymatic potential rates on proteinaceous (leucine-aminopeptidase) and glucidic (ß-glucosidase) organic matter and on organic phosphates (alkaline-phosphatase) by fluorogenic substrates were tested. The adopted methodological approach gave useful information regarding viability and metabolic performances of microbial community in permafrost. The occurrence of a multifaceted prokaryotic community in the Victoria Land permafrost and a large number of potentially viable and respiring cells (in the order of 10 4 -10 5 ) were recognised. Subpopulations with a different apparent DNA content within the different samples were observed. The physiological profiles stressed various potential metabolic pathways among the samples and intense utilisation rates of polymeric carbon compounds and carbohydrates

  2. A review of the influence of biogeography, riverine linkages, and marine connectivity on fish assemblages in evolving lagoons and lakes of coastal southern Africa.

    Whitfield, Alan K; Weerts, Steven P; Weyl, Olaf L F

    2017-09-01

    The Holocene evolution of eight South African coastal lakes and lagoons is examined and related to changes in fish composition over that period. Historical and current connectivity with riverine and marine environments are the primary determinants of present-day fish assemblages in these systems. A small and remarkably consistent group of relict estuarine species have persisted in these coastal lakes and lagoons. The loss or reduction of connectivity with the sea has impacted on the diversity of marine fishes in all eight study systems, with no marine fishes occurring in those water bodies where connectivity has been completely broken (e.g. Sibaya, Groenvlei). In systems that have retained tenuous linkages with the sea (e.g., Verlorenvlei, Wilderness lakes), elements of the marine fish assemblage have persisted, especially the presence of facultative catadromous species. Freshwater fish diversity in coastal lakes and lagoons is a function of historical and present biogeography and salinity. From a freshwater biogeography perspective, the inflowing rivers of the four temperate systems reviewed here contain three or fewer native freshwater fishes, while the subtropical lakes that are fed by river systems contain up to 40 freshwater fish species. Thus, the significantly higher fish species diversity in subtropical versus temperate coastal lakes and lagoons comes as no surprise. Fish species diversity has been increased further in some systems (e.g., Groenvlei) by alien fish introductions. However, the impacts of fish introductions and translocations have not been studied in the coastal lakes and lagoons of South Africa. In these closed systems, it is probable that predation impacts on small estuarine fishes are significant. The recent alien fish introductions is an example of the growing threats to these systems during the Anthropocene, a period when human activities have had significant negative impacts and show potential to match the changes recorded during the

  3. Chronic genetic damages in Geophagus brasiliensis exposed to anthropic impact in estuarine lakes at Santa Catarina coast--southern of Brazil.

    Benincá, Cristiane; Ramsdorf, Wanessa; Vicari, Taynah; de Oliveira Ribeiro, Ciro A; de Almeida, Marina I; Silva de Assis, Helena C; Cestari, Marta Margarete

    2012-04-01

    Biological monitoring through animals exposed to pollutants using biomarkers provides a promising tool for the identification of pollutants that may cause damage to human health and/or to sustainability of ecosystems. The effects of pollutants in fish tissues are important tools to understand the impact of human activities in natural ecosystems. The aim of this work was to study the water quality of two estuarine lakes in Santa Catarina, Brazil (Camacho Lake and Santa Marta Lake). Geophagus brasiliensis is a species widely distributed in Brazil and was used in this work. Comet assays in peripheral red blood and kidney cells, micronucleus tests in peripheral red blood cells, measurements of acetylcholinesterase activity in axial muscle and histopathological analysis of liver were used as biomarkers. Three sampling campaigns were undertaken in November 2004, June 2005 and November 2005. Thirty adult animals were sampled from each of three different sites (P1--Santa Marta Lake, P2 and P3--Camacho Lake). A negative control was sampled in a non-polluted site at Costa Ecological Park, Paraná. The positive control for genotoxicity was obtained by treating animals with copper sulphate. The results showed that both studied lakes are impacted by potential genotoxic substances. Severe lesions in liver of G. brasiliensis were also observed. The inhibition of acetylcholinesterase activity suggests the presence of pesticides or metals in the studied sites. This work shows that the water quality of Santa Marta and Camacho Lakes have been compromised and further control source of pollutants into these ecosystems is required.

  4. Sedimentary architecture and palaeogeography of lower Slochteren Aeolian cycles from the Rotliegend desert-lake margin (Permian), the Markham area, Southern North Sea

    Belt, F.J.G. van den; Hulten, F.F.N. van

    2011-01-01

    The Rotliegend gas play in the Southern Permian Basin has yielded over 200 gas fields in the Netherlands; they are found in an E-W fairway along the southern flank of the basin. Sandstones generally pinch out basinward, but localized, isolated sands are present north of the main fairway. The

  5. Paediatric doses from diagnostic radiology in Victoria

    Boal, T.J.; Cardillo, I.; Einsiedel, P.F.

    1998-01-01

    This study examines doses to paediatric patients from diagnostic radiology. Measurements were made at 29 hospitals and private radiology practices in the state of Victoria. Entrance skin doses in air were measured for the exposure factors used by hospital radiology departments and private radiology practices for a standard size 1, 5, 10 and 15 year old child, for the following procedures: chest AP/PA, lat; abdomen AP; pelvis AP; lumbar spine AP, lat; and skull AP, lat. There was a large range of doses for each particular procedure and age group. Factors contributing to the range of doses were identified. Guidance levels for paediatric radiology based on the third quartile value of the skin entrance doses have been recommended and are compared with guidance levels. Copyright (1998) Australasian Physical and Engineering Sciences in Medicine

  6. Layers of 'Cabo Frio' in 'Victoria Crater'

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  7. Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

    E. W. Helbling

    2013-02-01

    Full Text Available Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada, used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a solar radiation: UVR + PAR (280–700 nm versus PAR (photosynthetically active radiation alone (400–700 nm; (b nutrient addition (phosphorus (P and nitrogen (N: ambient versus addition (P to reach to a final concentration of 30 μg P L−1, and N to reach N:P molar ratio of 31; and (c mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min−1, total of 10 cycles versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The

  8. Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes in Southern Europe

    Helbling, E. W.; Carrillo, P.; Medina-Sánchez, J. M.; Durán, C.; Herrera, G.; Villar-Argaiz, M.; Villafañe, V. E.

    2013-02-01

    Global change, together with human activities, has resulted in increasing amounts of organic material (including nutrients) that water bodies receive. This input further attenuates the penetration of solar radiation, leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR) than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, for which the effects have, in general, been neglected. Furthermore, the combined impacts of mixing, together with those of UVR and nutrient inputs are virtually unknown. In this study, we carried out complex in situ experiments in three high mountain lakes of Spain (Lake Enol in the National Park Picos de Europa, Asturias, and lakes Las Yeguas and La Caldera in the National Park Sierra Nevada, Granada), used as model ecosystems to evaluate the joint impact of these climate change variables. The main goal of this study was to address the question of how short-term pulses of nutrient inputs, together with vertical mixing and increased UVR fluxes modify the photosynthetic responses of phytoplankton. The experimentation consisted in all possible combinations of the following treatments: (a) solar radiation: UVR + PAR (280-700 nm) versus PAR (photosynthetically active radiation) alone (400-700 nm); (b) nutrient addition (phosphorus (P) and nitrogen (N)): ambient versus addition (P to reach to a final concentration of 30 μg P L-1, and N to reach N:P molar ratio of 31); and (c) mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m 4 min-1, total of 10 cycles)) versus static. Our findings suggest that under ambient nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and excretion of organic carbon (EOC) from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The opposite occurs in clear lakes where

  9. Interactive effects of vertical mixing, nutrients and ultraviolet radiation: in situ photosynthetic responses of phytoplankton from high mountain lakes of Southern Europe

    Helbling, E. W.; Carrillo, P.; Medina-Sanchez, J. M.; Durán, C.; Herrera, G.; Villar-Argaiz, M.; Villafañe, V. E.

    2012-07-01

    Global change, together with human activities had resulted in increasing amounts of organic material (including nutrients) received by water bodies. This input further attenuates the penetration of solar radiation leading to the view that opaque lakes are more "protected" from solar ultraviolet radiation (UVR) than clear ones. Vertical mixing, however, complicates this view as cells are exposed to fluctuating radiation regimes, which effects have in general been neglected. Even more, the combined impacts of mixing, together with those of UVR and nutrients input are virtually unknown. In this study, we carried out in situ experiments in three high mountain lakes of Spain (Lake Enol in Asturias, and lakes Las Yeguas and La Caldera in Granada) to determine the combined effects of these three variables associated to global change on photosynthetic responses of natural phytoplankton communities. The experimentation consisted in all possible combinations of the following treatments: (a) solar radiation: UVR + PAR (280-700 nm) versus PAR alone (400-700 nm); (b) nutrient addition (phosphorus (P) and nitrogen (N)): ambient versus addition (P to reach to a final concentration of 30 μg P l-1, and N to reach a N : P molar ratio of 31) and, (c) mixing: mixed (one rotation from surface to 3 m depth (speed of 1 m every 4 min, total of 10 cycles) versus static. Our findings suggest that under in situ nutrient conditions there is a synergistic effect between vertical mixing and UVR, increasing phytoplankton photosynthetic inhibition and EOC from opaque lakes as compared to algae that received constant mean irradiance within the epilimnion. The opposite occurs in clear lakes where antagonistic effects were determined, with mixing partially counteracting the negative effects of UVR. Nutrients input mimicking atmospheric pulses from Saharan dust, reversed this effect and clear lakes became more inhibited during mixing, while opaque lakes benefited from the fluctuating irradiance

  10. The Bands Culture in Victoria, Australia: Live Music Benefits Career Paths, Employment and Community

    Watson, Amanda; Forrest, David

    2012-01-01

    This study explores the career paths, employment, business opportunities and community contributions made available through the provision and development of the contemporary performance bands' culture in the State of Victoria. It is framed with the support given to live music performers by Arts Victoria, Small Business Victoria and Music Victoria.…

  11. Snapping Turtles (Chelydra serpentina) from Canadian Areas of Concern across the southern Laurentian Great Lakes: Chlorinated and brominated hydrocarbon contaminants and metabolites in relation to circulating concentrations of thyroxine and vitamin A.

    Letcher, Robert J; Lu, Zhe; de Solla, Shane R; Sandau, Courtney D; Fernie, Kimberly J

    2015-11-01

    The metabolites of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), as well as other halogenated phenolic contaminants (HPCs) have been shown to have endocrine-disrupting properties, and have been reported with increasing frequency in the blood of wildlife, and mainly in mammals and birds. However, little is known about the persistence, accumulation and distribution of these contaminants in long-lived freshwater reptiles. In the present study, in addition to a large suite of chlorinated and brominated contaminants, metabolites and HPCs, we assessed and compared hydroxylated (OH) PCBs and OH-PBDEs relative to PCBs and PBDEs, respectively, in the plasma of adult male common snapping turtles (Chelydra serpentina). Blood samples were collected from 62 snapping turtles (2001-2004) at 12 wetland sites between the Detroit River and the St. Lawrence River on the Canadian side of the Laurentian Great Lakes of North America. Turtles were sampled from sites designated as Areas of Concern (AOCs) and from a relatively clean reference site in southern Georgian Bay (Tiny Marsh), Lake Huron. Plasma concentrations of Σ46PCB (10-340 ng/g wet weight (ww)) and Σ28OH-PCB (3-83 ng/g ww) were significantly greater (pturtles from the Turkey Creek and Muddy Creek-Wheatley Harbour sites in Lake Erie compared with the reference site turtles. The HPC, pentachlorophenol (PCP), had a mean concentration of 9.6±1.1 ng/g ww. Of the 28 OH-CB congeners screened for, 4-OH-CB187 (42±7 ng/g ww) was the most concentrated of all HPCs measured. Of the 14 OH-BDE congeners examined, four (4'-OH-BDE17, 3-OH-BDE47, 5-OH-BDE47 and 4'-OH-BDE49) were consistently found in all plasma samples. p,p'-DDE was the most concentrated of the 18 organochlorine pesticides (OCPs) examined. The mean concentrations of circulating total thyroxine (TT4), dehydroretinol and retinol in the plasma of the male snapping turtles regardless of sampling site were 5.4±0.3, 81±4.7 and 291±13 ng

  12. Microbial community in a sediment-hosted CO(2) lake of the southern Okinawa Trough hydrothermal system RID C-8303-2011

    Inagaki, Fumio; Kuypers, Marcel M. M.; Tsunogai, Urumu

    2006-01-01

    pavements above the CO(2) lake, decreasing to strikingly low cell numbers (107 CM-3) at the liquid CO(2)/CO(2)-hydrate interface. The key groups in these sediments were as follows: (i) the anaerobic methanotrophic archaea ANME-2c and the Eel-2 group of Deltaproteobacteria and (ii) sulfur...

  13. Victoria Land, Ross Sea, and Ross Ice Shelf, Antarctica

    2002-01-01

    On December 19, 2001, MODIS acquired data that produced this image of Antarctica's Victoria Land, Ross Ice Shelf, and the Ross Sea. The coastline that runs up and down along the left side of the image denotes where Victoria Land (left) meets the Ross Ice Shelf (right). The Ross Ice Shelf is the world's largest floating body of ice, approximately the same size as France. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  14. Changes in Rongbuk lake and Imja lake in the Everest region of Himalaya

    Chen, W.; Doko, T.; Liu, C.; Ichinose, T.; Fukui, H.; Feng, Q.; Gou, P.

    2014-12-01

    The Himalaya holds the world record in terms of range and elevation. It is one of the most extensively glacierized regions in the world except the Polar Regions. The Himalaya is a region sensitive to climate change. Changes in the glacial regime are indicators of global climate changes. Since the second half of the last century, most Himalayan glaciers have melted due to climate change. These changes directly affected the changes of glacial lakes in the Himalayan region due to the glacier retreat. New glacial lakes are formed, and a number of them have expanded in the Everest region of the Himalayas. This paper focuses on the two glacial lakes which are Imja Lake, located at the southern slope, and Rongbuk Lake, located at the northern slope in the Mt. Everest region, Himalaya to present the spatio-temporal changes from 1976 to 2008. Topographical conditions between two lakes were different (Kruskal-Wallis test, p < 0.05). Rongbuk Lake was located at 623 m higher than Imja Lake, and radiation of Rongbuk Lake was higher than the Imja Lake. Although size of Imja Lake was larger than the Rongbuk Lake in 2008, the growth speed of Rongbuk Lake was accelerating since 2000 and exceeds Imja Lake in 2000-2008. This trend of expansion of Rongbuk Lake is anticipated to be continued in the 21st century. Rongbuk Lake would be the biggest potential risk of glacial lake outburst flood (GLOF) at the Everest region of Himalaya in the future.

  15. Monitoring geodynamic activity in the Victoria Land, East Antarctica: Evidence from GNSS measurements

    Zanutta, A.; Negusini, M.; Vittuari, L.; Cianfarra, P.; Salvini, F.; Mancini, F.; Sterzai, P.; Dubbini, M.; Galeandro, A.; Capra, A.

    2017-10-01

    GNSS networks in Antarctica are a fundamental tool to define actual crustal displacements due to geological and geophysical processes and to constrain the glacial isostatic models (GIA). A large network devoted to the detection and monitoring of crustal deformations in the Northern Victoria Land (Victoria Land Network for DEFormation control - VLNDEF), was monumented during the 1999-2000 and 2000-2001 field campaigns, as part of Italian National Program for Antarctic Research and surveyed periodically during the Southern summer seasons. In this paper, GPS observations of VLNDEF collected over a more than 15-year span, together with various selected POLENET sites and more than 70 IGS stations, were processed with Bernese Software, using a classical double difference approach. A solution was obtained combining NEQs by means of ADDNEQ2/FODITS tools embedded in Bernese Software. All the Antarctic sites were kept free and a subset of 50 IGS stations were used to frame VLNDEF into ITRF2008. New evidence provided by analysis of GPS time series for the VLNDEF network is presented; also displacements along the vertical component are compared with the recently published GIA models. The absolute velocities indicate an overall displacement of the northern Victoria Land region along the south-east direction (Ve = 10.6 mm/yr, Vn = -11.5 mm/yr) and an average uplift rate of Vu = 0.5 mm/yr. Two GIA models have been analyzed: ICE-6G_C-VM5a proposed by Argus et al. (2014), Peltier et al. (2015) and W12A_v1 by Whitehouse et al. (2012a,b). Up rates, predicted over the VLNDEF sites by the mentioned GIA models, have been extracted and compared with those observed. A preliminary comparison with GPS-derived vertical rates shows that the Victoria Land ICE-6G_C-VM5 and W12A_v1 GIA models predict overestimated uplift rates of 0.7 and 0.9 mm/yr weighted mean residuals respectively. The mean horizontal relative motions within the Victoria Land (VL) area are in most cases negligible, while only

  16. Recent plant studies using Victoria 2.0

    Bixler, Nathan E.; Gasser, Ronald D.

    2000-01-01

    VICTORIA 2.0 is a mechanistic computer code designed to analyze fission product behavior within the reactor coolant system (RCS) during a severe nuclear reactor accident. It provides detailed predictions of the release of radioactive and nonradioactive materials from the reactor core and transport and deposition of these materials within the RCS and secondary circuits. These predictions account for the chemical and aerosol processes that affect radionuclide behavior. VICTORIA 2.0 was released in early 1999; a new version VICTORIA 2.1, is now under development. The largest improvements in VICTORIA 2.1 are connected with the thermochemical database, which is being revised and expanded following the recommendations of a peer review. Three risk-significant severe accident sequences have recently been investigated using the VICTORIA 2.0 code. The focus here is on how various chemistry options affect the predictions. Additionally, the VICTORIA predictions are compared with ones made using the MELCOR code. The three sequences are a station blackout in a GE BWR and steam generator tube rupture (SGTR) and pump-seal LOCA sequences in a 3-loop Westinghouse PWR. These sequences cover a range of system pressures, from fully depressurized to full system pressure. The chief results of this study are the fission product fractions that are retained in the core, RCS, secondary, and containment and the fractions that are released into the environment

  17. vVICTORIA Console Development: Design and Fabrication of VICTORIA Console Emulations

    2011-07-01

    successful set-up and readiness to conduct experimentation on facets of new Combat System concept development including equipment capabilities, system...émulateurs, faits de bois, de plastiques et de métaux légers, ont été fabriqués selon les données matérielles et les spécifications des consoles actuelles...mise sur pied du laboratoire d’évaluation de la capacité vVictoria et assureront que celui-ci est prêt pour les essais de nouveaux concepts de système

  18. Turning attention to clinician engagement in Victoria.

    Jorm, Christine; Hudson, Robyn; Wallace, Euan

    2017-11-16

    The engagement of clinicians with employing organisations and with the broader health system results in better safer care for patients. Concerns about the adequacy of clinician engagement in the state of Victoria led the Victorian Department of Health and Human Services to commission a scoping study. During this investigation more than 100 clinicians were spoken with and 1800 responded to surveys. The result was creation of a clear picture of what engagement and disengagement looked like at all levels - from the clinical microsystem to state health policy making. Multiple interventions are possible to enhance clinician engagement and thus the care of future patients. A framework was developed to guide future Victorian work with four elements: setting the agenda, informing, involving and empowering clinicians. Concepts of work or employee engagement that are used in other industries don't directly translate to healthcare and thus the definition of engagement chosen for use centred on involvement. This was designed to encourage system managers to ensure clinicians are full participants in design, planning and evaluation and in all decisions that affect them and their patients.

  19. Efficient renewable energy scenarios study for Victoria

    Armstrong, Graham

    1991-01-01

    This study examines the possible evolution of Victorian energy markets over the 1998-2030 period from technical, economic and environmental perspectives. The focus is on the technical and economic potential over the study period for renewable energy and energy efficiency to increase their share of energy markets, through their economic competitiveness with the non-renewables of oil, gas and fossil fulled electricity. The study identifies a range of energy options that have a lower impact on carbon dioxide emissions that current projections for the Victorian energy sector, together with the savings in energy, dollars and carbon dioxide emissions. In addition the macroeconomic implications of the energy paths are estimated. Specifically it examines a scenario (R-efficient renewable) where energy efficiency and renewable energy sources realise their estimated economic potential to displace non-renewable energy over the 1988-2030 period. In addition, a scenario (T-Toronto) is examined where energy markets are pushed somewhat harder, but again on an economic basis, so that what is called the Toronto target of reducing 1988 carbon dioxide (CO 2 ) emissions by 20 per cent by 2005 is attained. It is concluded that over the next forty years there is substantial economic potential in Victoria for significant gains from energy efficiency in all sectors - residential, commercial, industrial and transport - and contributions from renewable energy both in those sectors and in electricity generations. 7 figs., 5 tabs

  20. Occupational skin disease in Victoria, Australia.

    Cahill, Jennifer L; Williams, Jason D; Matheson, Melanie C; Palmer, Amanda M; Burgess, John A; Dharmage, Shyamali C; Nixon, Rosemary L

    2016-05-01

    To describe the characteristics of patients with occupational skin disease (OSD) in a tertiary referral clinic in Victoria, Australia. A retrospective review was conducted of records from patients seen at the Occupational Dermatology Clinic in Melbourne, Australia between 1 January 1993 and 31 December 2010. Of the 2894 people assessed in the clinic during the 18-year period, 44% were women and 56% were men. In all, 2177 (75%) were diagnosed with occupational skin disease (OSD). Of the patients with a work-related skin condition, 45% (n = 979) were considered to be atopic. The most common diagnosis in those with OSD was irritant contact dermatitis (ICD) (44%), followed by allergic contact dermatitis (33%) and endogenous eczema (11%). Women were significantly more likely to have soaps and detergents (P Occupational groups with the highest incidence of OSD were the hair and beauty professions (70 per 100 000), followed by machine and plant operators (38 per 100 000) and health-care workers (21 per 100 000). We confirm the importance of occupational contact dermatitis as the most common cause of OSD, with ICD being the most common diagnosis. There are differences in the causes of ICD between our group of male and female workers. For the first time in Australia, rates of OSD in certain industries have been calculated. © 2015 The Australasian College of Dermatologists.

  1. Whole-genome sequence of a freshwater aerobic anoxygenic phototroph, Porphyrobacter sp. strain AAP82, isolated from the Huguangyan Maar Lake in Southern China

    Li, X.; Koblížek, Michal; Feng, F.; Li, Y.; Jian, J.; Zeng, Yonghui

    2013-01-01

    Roč. 1, č. 2 (2013) ISSN 2169-8287 R&D Projects: GA ČR GAP501/10/0221; GA MŠk(CZ) ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : Porphyrobacter * Huguangyan Maar Lake Subject RIV: EE - Microbiology, Virology http://genomea. asm .org/content/1/2/e00072-13.full

  2. Organochlorine and trace element contamination in wintering and migrating diving ducks in the southern Great Lakes, USA, since the zebra mussel invasion

    Custer, Christine M.; Custer, T.W.

    2000-01-01

    Because of the potential for increased trophic transfer of contaminants by zebra mussels (Dreissena sp.) to higher trophic levels, we collected four species of waterfowl (n = 65 ducks) from four locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA, between 1991 and 1993 for organochlorine contaminant and trace element analyses. Geometric mean concentrations of total polychlorinated biphenyls (PCBs) and p,pa??-dichlorodiphenyldichloroethylene (DDE) were 1.35 and 0.15 I?g/g wet weight in lesser scaup (Aythya affinis) carcasses and were below known effect levels. Total PCBs in 80% of carcasses, however, were above the U.S. Food and Drug Administration's threshold of 3.0 I?g/g lipid weight for consumption of poultry. With the exception of selenium, trace elements were also at background or no-effect levels. Selenium concentrations in livers of 95% of lesser scaup, 90% of bufflehead (Bucephala albeola), and 72% of common goldeneye (Bucephala clangula) were in the elevated (>10 I?g/g dry wt) or potentially harmful range (>33 I?g/g dry wt). The effects of these high selenium concentrations are unknown but should be investigated further based on reproductive effects observed in field and laboratory studies of dabbling ducks and because lesser scaup populations are declining. Concentrations of total PCBs in dreissenid mussels in western Lake Erie were 10 times higher than in the upper Mississippi River but were similar to concentrations in other industrialized rivers in Europe and the United States. Metal concentrations were similar to other industrialized sites where zebra mussels have been sampled.

  3. Spatio-temporal assessment of soil erosion risk in different agricultural zones of the Inle Lake region, southern Shan State, Myanmar.

    Htwe, Thin Nwe; Brinkmann, Katja; Buerkert, Andreas

    2015-10-01

    Myanmar is one of Southeast Asia's climatically most diverse countries, where sheet, rill, and gully erosion affect crop yields and subsequently livelihood strategies of many people. In the unique wetland ecosystem of Inle Lake, soil erosion in surrounding uplands lead to sedimentation and pollution of the water body. The current study uses the Revised Universal Soil Loss Equation (RUSLE) to identify soil erosion risks of the Inle Lake region in space and time and to assess the relationship between soil erosion and degradation for different agricultural zones and cropping systems. Altogether, 85% of soil losses occurred on barren land along the steep slopes. The hotspot of soil erosion risk is situated in the western uplands characterized by unsustainable land use practices combined with a steep topography. The estimated average soil losses amounted to 19.9, 10.1, and 26.2 t ha(-1) yr(-1) in 1989, 2000, and 2009, respectively. These fluctuations were mainly the results of changes in precipitation and land cover (deforestation (-19%) and expansion of annual cropland (+35%) from 1989 to 2009). Most farmers in the study area have not yet adopted effective soil protection measures to mitigate the effects of soil erosion such as land degradation and water pollution of the lake reservoir. This urgently needs to be addressed by policy makers and extension services.

  4. Lake Chad, Chad, Africa

    1992-01-01

    Hydrologic and ecologic changes in the Lake Chad Basin are shown in this Oct 1992 photograph. In space photo documentation, Lake Chad was at its greatest area extent (25,000 sq. km.) during Gemini 9 in June 1966 (see S66-38444). Its reduction during the severe droughts from 1968 to 1974 was first noted during Skylab (1973-1974). After the drought began again in 1982, the lake reached its minimum extent (1,450 sq. km.) in Space Shuttle photographs taken in 1984 and 1985. In this STS-52 photograph, Lake Chad has begun to recover. The area of the open water and interdunal impoundments in the southern basin (the Chari River Basin) is estimated to be 1,900 to 2100 sq. km. Note the green vegetation in the valley of the K'Yobe flow has wetted the northern lake basin for the first time in several years. There is evidence of biomass burning south of the K'Yobe Delta and in the vegetated interdunal areas near the dike in the center of the lake. Also note the dark 'Green Line' of the Sahel (the g

  5. Interactions between climate and vegetation during the Lateglacial period as recorded by lake and mire sediment archives in Northern Italy and Southern Switzerland

    Vescovi, E.; Ravazzi, C.; Arpenti, E.; Finsinger, W.; Pini, R.; Valsecchi, V.; Wick, L.; Ammann, B.; Tinner, W.

    2007-01-01

    We reconstruct the vegetational history of the southern side of the Alps at 18,000–10,000 cal yr BP using previous and new AMS-dated stratigraphic records of pollen, stomata, and macrofossils. To address potential effects of climatic change on vegetation, we compare our results with independent

  6. Population dynamics of Chaoborus flavicans and Daphnia spp.: effects on a zooplankton community in a volcanic eutrophic lake with naturally high metal concentrations (L. Monticchio Grande, Southern Italy

    Letizia GARIBALDI

    2009-02-01

    Full Text Available The response of Daphnia populations to invertebrate predators involves morphological or behavioural changes. Few studies suggest that contaminant aqueous metals, like Cu or Ni at environmentally relevant concentrations, interfere with invertebrate chemical communication systems, such as that which operates between Daphnia and Chaoborus. The objective of our study was to determine if this interference could be also observed in lakes naturally rich in dissolved metals, such as volcanic lake (Lago Grande di Monticchio. This study aimed to assess if natural dissolved metals (e.g., Fe, Mn and Sr could impair the ability of Daphnia pulex and D. galeata × hyalina × cucullata 'complex' populations to respond to Chaoborus kairomones by producing morphological defenses against potential predation, and to understand how Chaoborus predation might affect zooplankton community composition and overall zooplankton density. The predator impact did not result in: i any morphological changes; ii any apparent shift in body size pattern of the prey population; iii any shift in life history traits. Chaoborus accounted for high mortality rates in Cladocera and strongly reduced the chance of individuals to reach maturity. Moreover, highly significant negative correlations between abundance of dominant taxa of zooplankton and C. flavicans were found. The last larval instars of C. flavicans seem to reduce the number of crustaceans, particularly cladocerans and copepod adults and could play an important role in structuring zooplankton communities. Our results suggest that metal inhibition of defence strategies induction probably occurs along the signal transduction pathway in Lake Grande di Monticchio. Impairment of chemosensory response to predatory chemical cues may have widespread ecological consequences in aquatic systems. Chaoborus predation effects can greatly affect both zooplankton biomass and community composition, impact interactions at lower trophic levels

  7. Assessment of deep electrical conductivity features of Northern Victoria Land (Antarctica under other geophysical constraints

    A. Caneva

    2000-06-01

    Full Text Available The lithospheric and crustal structure of the Victoria Land continental block (Antarctica has been studied by geological and geophysical surveys. Among them magnetovariational investigations (MV have been addressed to highlight the deep electrical conductivity patterns which contribute to the understanding of continental rifting and tectonic setting of the region. The hypothetical event map for H linearly polarized perpendicular to the coast indicates a possible broad coast parallel conductivity anomaly zone. Despite the coast effect, this feature could be related to the deep upper mantle thermal anomaly leading to Cenozoic uplift of the Transantarctic Mountains rift flank. However, both the hypothetic event map polarized parallel to the coast and the induction arrows suggest that the area of enhanced conductivity may be confined to the Deep Freeze Range crustal block along the western flank of the Mesozoic Rennick Graben. We also discuss the possible association between increased conductivity over the Southern Cross block and extensive Cenozoic alkaline plutonism.

  8. Accession of non-nitrogenous ions dissolved in rainwater to soils in Victoria

    Hutton, J T; Leslie, T I

    1958-01-01

    Analyses of rainwater samples from 24 stations in Victoria have shown that with increasing distance from the coast there is a sharp decrease in the influence of the ocean on the nature of the dissolved ions. About 150 miles inland the ionic ratio of sodium to potassium falls below 10, that of sodium to chloride exceeds unity, and calcium becomes the dominant cation. This is considered to reflect the influence of terrestrial material such as the dry surface of soils. As soils also contain sodium and chloride ions, the common assumption that all the chloride in the rain is derived from the ocean is unjustified, hence calculations of the net accession of salts are unwarranted. In southern Australia, sulphate ions are present in much smaller amounts than in other countries and this may contribute to the observed deficiencies of sulphur in plant nutrition. Details are given of the method of collecting the rainwater and of its analysis.

  9. State Electricity Commission of Victoria. Annual report 1984-1985

    1985-01-01

    The State Electricity Commission of Victoria is a body corporate first constituted under the Electricity Commissioner's Act 1918. It now operates under the State Electricity Commission Act 1958. It generates, transmits and distributes electricity throughout Victoria's 228,000 square kilometres and supplies directly to 1.424 million customers. In addition 277,800 customers are supplied by eleven municipal authorities which purchase electricity in bulk from the Commission. The Commission also has a regulatory responsibility to ensure the safe use of electricity. It employs 22,518 people. The installed capacity of generators in the Commission's system, plus Victoria's share of Snowy and Hume generation, totalled 6603 MW at 30 June 1985 and the main transmission system comprises 500 kV, 300 kV and 220 kV lines. Corporate objectives have been developed in seven broad areas: customers,employee, finance, ntural resources, environment, conservationand community. These areas of activity are detailed in this report.

  10. Funding Victoria's public hospitals: the casemix policy of 2000-2001.

    McNair, Peter; Duckett, Stephen

    2002-01-01

    On 1 July 1993 Victoria became the first Australian state to use casemix information to set budgets for its public hospitals commencing with casemix funding for inpatient services. Victoria's casemix funding approach now embraces inpatient, outpatient and rehabilitation services.

  11. Optimization of EDXRF for the study of heavy metal pollution of Lake ...

    The spectrometer was subsequently utilized to determine concentrations of heavy metals in water hyacinth (Eichhornia crassipes (Mart) Solms.) found growing along the shore of Lake Victoria. The optimal conditions and detection limits were determined experimentally by variation of the excitation parameters. The study ...

  12. Victoria Law School Ten Years On—A Time to Pause and Reflect

    Andrew Clarke

    2013-11-01

    Full Text Available On 4 November 2010, a large and distinguished audience assembled at the Queen Street Campus of Victoria University to celebrate the tenth anniversary of the founding of Victoria Law School. This Foreword records the diverse achievements of Victoria Law School over the past decade.

  13. Victoria Law School Ten Years On—A Time to Pause and Reflect

    Andrew Clarke

    2013-01-01

    On 4 November 2010, a large and distinguished audience assembled at the Queen Street Campus of Victoria University to celebrate the tenth anniversary of the founding of Victoria Law School. This Foreword records the diverse achievements of Victoria Law School over the past decade.

  14. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  15. The influence of climate variability on numbers of three waterbird species in Western Port, Victoria, 1973 2002

    Chambers, Lynda E.; Loyn, Richard H.

    2006-05-01

    Seasonal and annual movements of Australian waterbirds are generally more complex than those of their Northern Hemisphere counterparts, and long-term data are needed to understand their relationships with climatic variables. This paper explores a long-term (1973 2002) set of waterbird counts from coastal Victoria and relates them to climatic data at local and continental scales. Three species (Black Swan Cygnus atratus, White-faced Heron Egretta novaehollandiae and Grey Teal Anas gracilis) were chosen for this analysis. Black Swans have large local breeding populations near the study region; White-faced Herons have smaller local breeding populations and Grey Teal breed extensively in ephemeral inland floodplains, such as those in the Murray-Darling Basin. All showed significant relationships with streamflow, regional rainfall and the Southern Oscillation Index (SOI) at appropriate scales and time-lags, with streamflow explaining the most variance. Black Swans showed a strong seasonal cycle in abundance and local climate variables had the greatest influence on the counts. Numbers were positively correlated with streamflow in southern Victoria three to six seasons before each count. Broader-scale climatic patterns were more important for the other two species. Numbers of White-faced Herons were positively correlated with streamflow or rainfall over various parts of Australia seven to nine seasons before each count. Numbers of Grey Teal showed weak seasonal cycles, and were negatively correlated with rainfall in Victoria or the Murray-Darling Basin in the seasons before or during each count, and positively with streamflow in the Murray-Darling Basin 15 18 months before each count.

  16. Paleolakes in the Gobi region of southern Mongolia

    Lehmkuhl, Frank; Grunert, Jörg; Hülle, Daniela; Batkhishig, Ochirbat; Stauch, Georg

    2018-01-01

    Numerous lakes and remnants of paleolakes exist in western and southern Mongolia. For six basins in the area, detailed geomorphological maps were compiled, based on extensive field studies and remote sensing datasets. Several phases of high and low lake levels were reconstructed and dated by radiocarbon and optically stimulated luminescence. During the marine isotope stage (MIS) 6 lakes in southern and western Mongolia mostly disappeared. In contrast, large paleolakes existed during the last interglacial (MIS 5e) and lasted probably until the beginning of the last glacial. These huge lakes were caused by a strong East Asian summer monsoon, which reached southern and even western Mongolia. During the MIS 3 the monsoon was considerably weaker and most of the lakes were relatively small or even disappeared. Higher lake levels of this period were only recorded at the Orog Nuur. However, at this time the lake was fed by glacial melt water from the Khangai Mountains. The MIS 2 was again a very dry period. The previously supposed phase of synchronous high lake levels and glaciations in southern and western Mongolia is not supported by the data presented here. During the Holocene, lakes in the western and southern part of the study area evolved differently. Early Holocene high lake levels were reconstructed for the western lakes, while most of the southern lakes had highest lake levels in the mid-Holocene. These differences can be attributed to different moisture bearing atmospheric systems. In the late Holocene lake levels were generally low and in the last 50 years most lakes completely disappeared due to a strong human usage of the water resources.

  17. Evidence for a Drought-driven (pre-industrial) Regime Shift in an Australian Shallow Lake

    Mills, K.; Gell, P.; Doan, P.; Kershaw, P.; McKenzie, M.; Lewis, T.; Tyler, J. J.

    2015-12-01

    We present a 750-year record of ecosystem response to long-term drought history from Lake Colac, Victoria. Using multiple lines of evidence, we test the sensitivity and resilience of Lake Colac to independently reconstructed drought history. The sedimentary archive shows that Lake Colac appears to be sensitive to periods of drought. Following drought conditions c. CE 1390, the lake ecosystem indicates signs of recovery. A succession of droughts in the early 1500s initiates a change in the diatom flora, with freshwater species declining and replaced by saline tolerant species, though there is little interpretable change in aquatic palynomorphs. An inferred drought, around CE 1720 appears to precede a major switch in the lake's ecosystem. The lake became increasingly turbid and saline and there is a distinct switch from a macrophyte-dominated system to an algal-dominated system. The arrival of Europeans in Victoria (CE1840) appears to have little effect on the lake's ecosystem, but the terrestrial vegetation indicates regionally established changes including declines in native trees, especially Casuarina, and arrival and expansion of exotic shade or plantation trees Pinus and Cupressus as well as native and introduced weeds. As European impact in the catchment increases, nutrients appear to play a role in the modification of the lake's ecosystem. A long-term drying trend from c. CE 1975 is evident, culminating in the Millennium Drought, which suggests unprecedented conditions in the ecological history of the Lake.

  18. Job-Sharing at the Greater Victoria Public Library.

    Miller, Don

    1978-01-01

    Describes the problems associated with the management of part-time library employees and some solutions afforded by a job sharing arrangement in use at the Greater Victoria Public Library. This is a voluntary work arrangement, changing formerly full-time positions into multiple part-time positions. (JVP)

  19. Study of genetic variation in population of Bipolaris victoriae, the ...

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... Isolates of Bipolaris victoriae were analysed by random amplified polymorphic DNA (RAPD) techniques ... According to the protocol, samples ... and fungus species. But some of the isolates of fungus with high genetic similarity have the same origin (Figure. 1). Weikert et al. (2002) reported that species of ...

  20. Aboriginal Students in Victoria. ACER Research Monograph No. 3.

    de Lemos, Marion M.

    An estimated 80%-90% of all Aboriginal students enrolled in the primary and secondary schools of Victoria, Australia, were tested and surveyed to determine their numbers, distribution, attendance, achievement, attitudes, and school leaving patterns. Most of the 1244 Aboriginals surveyed attended state schools and 75% were schooled in rural areas.…

  1. Late-life depression and the death of Queen Victoria.

    Abrams, Robert C

    2010-12-01

    The objective of this study was to evaluate relationships between the death of Queen Victoria and the depressive episode she experienced during the last year of her life. The last volume of Queen Victoria's personal Journal was reviewed from a geriatrician's perspective, tracing the onset and course of depressive symptoms from entries beginning on 17 August 1900 and ending on 13 January 1901, 9 days before her death. The Queen's own words are supplemented with observations from contemporaneous secondary sources. The antecedents of Queen Victoria's late-life depression, including multiple losses, disabilities, and chronic pain, taken together with the presentation of vegetative, affective, and late cognitive symptoms, suggested the presence of a distinctively geriatric major depressive disorder. The absence of any other medical condition to explain the clinical picture seemed probable but not certain. Although historians and biographers have long been aware of Queen Victoria's final depression, the emphasis has mostly been on her earlier and prolonged mourning for her husband Prince Albert. Re-examined now, the Queen's Journal suggests that a severe late-life depressive episode occurring approximately in her last 5 months contributed meaningfully to her death. Copyright © 2010 John Wiley & Sons, Ltd.

  2. 3D DIGITAL CADASTRE JOURNEY IN VICTORIA, AUSTRALIA

    D. Shojaei

    2017-10-01

    Full Text Available Land development processes today have an increasing demand to access three-dimensional (3D spatial information. Complex land development may need to have a 3D model and require some functions which are only possible using 3D data. Accordingly, the Intergovernmental Committee on Surveying and Mapping (ICSM, as a national body in Australia provides leadership, coordination and standards for surveying, mapping and national datasets has developed the Cadastre 2034 strategy in 2014. This strategy has a vision to develop a cadastral system that enables people to readily and confidently identify the location and extent of all rights, restrictions and responsibilities related to land and real property. In 2014, the land authority in the state of Victoria, Australia, namely Land Use Victoria (LUV, has entered the challenging area of designing and implementing a 3D digital cadastre focused on providing more efficient and effective services to the land and property industry. LUV has been following the ICSM 2034 strategy which requires developing various policies, standards, infrastructures, and tools. Over the past three years, LUV has mainly focused on investigating the technical aspect of a 3D digital cadastre. This paper provides an overview of the 3D digital cadastre investigation progress in Victoria and discusses the challenges that the team faced during this journey. It also addresses the future path to develop an integrated 3D digital cadastre in Victoria.

  3. Organic matter geochemical signatures (TOC, TN, C/N ratio, δ13C and δ15N) of surface sediment from lakes distributed along a climatological gradient on the western side of the southern Andes.

    Contreras, Sergio; Werne, Josef P; Araneda, A; Urrutia, R; Conejero, C A

    2018-07-15

    Paleolimnological studies in western South America, where meteorological stations are scarce, are critical to obtain more realistic and reliable regional reconstructions of past climate and environmental changes, including vegetation and water budget variability. However, climate and environmental geochemical indicators must be tested before they can be applied with confidence. Here we present a survey of lacustrine surface sediment (core top, 0 to ~1cm) biogeochemical proxies (total organic carbon [TOC], total nitrogen [TN], carbon/nitrogen ratio [C/N ratio] and bulk organic δ 13 C and total δ 15 N) from a suite of 72 lakes spanning the transition from a Mediterranean climate with a patchwork of cultivated vegetation, pastureland, and conifers in central Chile to a rainy temperate climate dominated by broadleaf deciduous and evergreen forest further south. Sedimentary data are compared to the latitudinal and orographic climatic trends of the region based on the climatology (precipitation and temperature) produced with Climate Forecast System Reanalysis (CFSR) data and the modern Southern Hemisphere Westerly Winds (SWW) location. The geochemical data show inflection points at ~42°S latitude and ~1500m elevation that are likely related to the northern limit of influence of the SWW and elevation of the snow line, respectively. Overall the organic proxies were able to mimic climatic trends (Mean Annual Precipitation [MAP] and temperature [MAT]), indicating that they are a useful tool to be included in paleoclimatological reconstruction of the region. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. No fixed place of birth: unplanned BBAs in Victoria, Australia.

    McLelland, Gayle; McKenna, Lisa; Archer, Frank

    2013-02-01

    the primary objective-to present data on the incidence of unplanned births before arrival (BBAs) in Victoria between 1991 and 2008. The secondary objective-to provide an extensive literature review highlighting the issues surrounding an unplanned BBA. the incidence of BBAs in Victoria published in the relevant government reports. data were extracted from published government reports pertaining to perinatal statistics in Victoria-The Australian Institute of Health and Wellbeing and the Perinatal Data Collection Unit of Victoria. Data on place of birth for each year from both sources was identified and tabulated. Comparisons between the data sources were undertaken to provide a picture of the scope of out of hospital birth. the incidence and absolute numbers of unplanned birth before arrival (BBA) to hospital in Victoria, are low compared to the total births. However, this number is comparable to unplanned BBAs in other developed countries with similar health systems. The incidence of unplanned BBAs has slowly but steadily doubled since 1991-2008. The two data sources almost mirror each other except for 1999 when there was an unexplained difference in the reported incidence in unplanned BBAs. Maternal and neonatal outcomes are disproportionally much poorer after unplanned BBAs than either planned home births or in hospital births. Various maternal factors can increase the risk of an unplanned BBA. multiple approaches should be adopted to manage unplanned BBAs. Antenatal screening should be undertaken to identify the women most at risk. Strategies can be developed that will reduce poor neonatal and maternal outcomes, including education for women and their partners on immediate management of the newborn; ensuring paramedics have current knowledge on care during childbirth; and maternity and ambulance services should develop management plans for care of women having unplanned BBAs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Early Holocene estuary development of the Hesselø Bay area, southern Kattegat, Denmark and its implication for Ancylus Lake drainage

    Bendixen, Carina; Boldreel, Lars Ole; Jensen, Jørn Bo

    2017-01-01

    environment and a description of coastal processes associated with a river outlet into the bay are presented. Weichselian glacial deposits form the lowermost interpreted unit, covered by late glacial (LG) and postglacial (PG, Holocene) sediments. A funnel-shaped estuary existed at the mouth of channels......High-resolution shallow seismic data, sediment core information, radiocarbon dating and sequence stratigraphy have been used to interpret the late glacial to early Holocene geological evolution of Hesselø Bay in the southern Kattegat, Denmark. A reconstruction of the early Holocene coastal...... in the period 10.3–9.2 cal. ka BP; the channels drained water from south to north. The early PG is characterised by estuarine and coastal deposits. The early Holocene bars that developed in the estuary are preserved as morphological features on the present-day seabed, possibly as a result of rapid relative sea...

  6. Methylophaga natronica sp. nov., a new alkaliphilic and moderately halophilic, restricted-facultatively methylotrophic bacterium from soda lake of the Southern Transbaikal region.

    Doronina, Nina; Darmaeva, Tsyregma; Trotsenko, Yuri

    2003-09-01

    A new, moderately haloalkaliphilic and restricted-facultatively methylotrophic bacterium (strain Bur2T) with the ribulose monophosphate pathway of carbon assimilation is described. The isolate, which utilizes methanol, methylamine and fructose, is an aerobic, Gram-negative, asporogenous, motile short rod multiplying by binary fission. It is auxotrophic for vitamin B12, and requires NaHCO3 or NaCl for growth in alkaline medium. Cellular fatty acids profile consists primarily of straight-chain saturated C16:0, unsaturated C16:1 and C18:1 acids. The major ubiquinone is Q-8. The dominant phospholipids are phosphatidylethanolamine and phosphatidylglycerol. Diphosphatidylglycerol is also present. Optimal growth conditions are 25-29 degrees C, pH 8.5-9.0 and 2-3% (w/v) NaCl. Cells accumulate ectoine and glutamate as the main osmoprotectants. The G + C content of the DNA is 45.0 mol%. Based on 16S rDNA sequence analysis and DNA-DNA relatedness (25-35%) with type strains of marine and soda lake methylobacteria belonging to the genus Methylophaga, the novel isolate was classified as a new species of this genus and named Methylophaga natronica (VKM B-2288T).

  7. Aquatic macrophytes as indicators of water quality in subtropical shallow lakes, Southern Brazil Macrófitas aquáticas como indicadores da qualidade da água em pequenos lagos rasos subtropicais, Sul do Brasil

    Sabrina Amaral Pereira

    2012-03-01

    Full Text Available AIMS: We evaluated the potential of aquatic macrophyte communities as bioindicators in six small shallow lakes. METHODS: The sampling was conducted monthly for one year, during which all macrophytes were surveyed, and the water temperature, dissolved oxygen, pH, conductivity, total alkalinity, chlorophyll-a, suspended matter, total nitrogen (Nt and total phosphorus (Pt were measured. RESULTS: In total, forty-three species were recorded, and there were significant differences in the species richness and limnological conditions among the lakes studied. A canonical correspondence analysis showed that the concentration of nutrients (Nt and Pt, chlorophyll-a, suspended matter, dissolved oxygen and pH were the most important predictors of the distribution of macrophytes. Some emergents were related to the high concentration of nutrients, chlorophyll-a, and suspended matter. Moreover, the most submersed species were associated with environments with low nutrient concentrations and the lowest values chlorophyll-a and suspended matter. In addition, some species submerged and floating were related to low values pH, alkalinity and dissolved oxygen. Limnological differences between lakes may be cited as the main causes of the observed heterogeneous distribution of macrophytes. CONCLUSIONS: These results indicate the importance of limnological characteristics of the different environments in the macrophyte community composition and the potential role of this community as a bioindicator in shallow lakes in southern Brazil.OBJETIVO: Foi avaliado o potencial bioindicador da comunidade de macrófitas aquáticas em seis pequenos lagos rasos. MÉTODOS: O acompanhamento foi mensal durante um ano, sendo que em cada coleta, além do registro de todas as espécies de macrófitas foram determinadas a temperatura da água, oxigênio dissolvido, pH, condutividade elétrica, alcalinidade total, clorofila-a, material em suspensão, nitrogênio total (Nt e fósforo total

  8. Driving a Fishery along the Bumpy Ride of Today's Globalisation: The Case of the Australian Southern Rock Lobster Association

    Dentoni, D.; Lu, J.; English, F.; McBride, R.

    2012-01-01

    The case of the Australian Southern Rock Lobster Association describes real issues faced by the Market Development Manager of a collective agri-food organization (SRL) representing all the southern rock lobster fishermen in Victoria, South Australia and Tasmania. The case deals with recent

  9. Oligotrophic patterns in southern Chilean lakes: the relevance of nutrients and mixing depth Patrones oligotróficos en lagos del sur de Chile: relevancia de los nutrientes y de la profundidad de mezcla

    DORIS SOTO

    2002-06-01

    Full Text Available Southern Chilean monomictic, temperate lakes are generally oligotrophic with high water transparency, low productivity and some apparent resistance to disturbances such as phosphorus additions. This paper attempts to explain low chlorophyll-a values using descriptive and experimental approaches. Three different scales are used, (a a micro scale both in space and time, with experimental manipulations of N, P and total light in 24 enclosures in lake Llanquihue, (b a longer time scale analysing 18 months of data in several sites within lake Llanquihue grouped as salmon farming sites, town bays and control sites, and (c a broader time scale (9 years by monitoring lakes Puyehue, Rupanco and Llanquihue, all in the Araucanian lake region and Yelcho lake in the north Patagonian region. In the Llanquihue in-lake sampling, total phosphorus values varied between 1 and 12 mug L-1 between sites, showing marginal site effects, P = 0.09 (salmon sites had greater values, however, chlorophyll a (Chl-a concentrations were generally low (Los lagos monomicticos templados del sur de Chile son generalmente oligotróficos de gran transparencia, baja productividad y aparente resistencia a perturbaciones tales como adiciones de fósforo. Este trabajo intenta explicar los bajos valores de clorofila de acuerdo a aproximaciones descriptivas y experimentales. Se utilizan aquí tres escalas de aproximación; (a una microescala en espacio y tiempo con manipulaciones experimentales de nitrógeno (N, fósforo (P y luz en 24 limnocorrales ubicados en una bahía del lago Llanquihue, (b una escala mayor analizando 18 meses de muestreo en 10 sitios del lago Llanquihue agrupados como sitios de cultivo de salmones, bahías de ciudades y sitios de control, (c una escala aún mayor en tiempo y espacio monitoreando semestralmente por 9 años los lagos Puyehue, Rupanco, Llanquihue en la región de los Lagos Araucanos y el lago Yelcho en la región nor- patagónica. En el muestreo intra

  10. Myxomatosis: the occurrence of antibody to a soluble antigen of myxoma virus in wild rabbits, Oryctolagus cuniculus (L.), in Victoria, Australia.

    Edmonds, J W; Shepherd, R C; Nolan, I F

    1978-10-01

    The occurrence of antibody of myxoma virus in wild rabbits following epizootics is highest in the semi-arid north-west of Victoria and lowest in temperate southern Victoria. Occurrence ranges up to about 90% in the north-west and to about 70% in the south except on the Western Plains where epizootics are rare and antibody occurrence seldom exceeds 30%. The establishment of the European rabbit flea may be changing the pattern of occurrence of antibody in the north-west by causing spring outbreaks of myxomatosis. It is suggested that the effects of the replacement of a simple recurring system of epizootic and breeding season several months apart by the occurrence of myxomatosis twice in the same year, once coincident with the breeding season, will be complex. The occurrence of detectable antibody may be less dependent on the infection rate and may be dependent to some extent on the relative timing of spring myxomatosis and the breeding season.

  11. Complete mitochondrial DNA sequences of the Victoria tilapia (Oreochromis variabilis) and Redbelly Tilapia (Tilapia zilli): genome characterization and phylogeny analysis.

    Kinaro, Zachary Omambia; Xue, Liangyi; Volatiana, Josies Ancella

    2016-07-01

    The Cichlid fishes have played an important role in evolutionary biology, population studies and aquaculture industry with East African species representing a model suited for studying adaptive radiation and speciation for cichlid genome projects in which closely related genomes are fast emerging presenting questions on phenotype-genotype relations. The complete mitochondrial genomes presented here are for two closely related but eco-morphologically distinct Lake Victoria basin cichlids, Oreochromis variabilis, an endangered native species and Tilapia zilli, an invasive species, both of which are important economic fishes in local areas. The complete mitochondrial genomes determined for O. variabilis and T. zilli are 16 626 and 16,619 bp, respectively. Both the mitogenomes contain 13 protein-coding genes, 22 tRNAs, 2 rRNAs and a non-coding control region, which are typical of vertebrate mitogenomes. Phylogenetic analyses of the two species revealed that though both lie within family Cichlidae, they are remotely related.

  12. Investigation of a steam generator tube rupture sequence using VICTORIA

    Bixler, N.E.; Erickson, C.M.; Schaperow, J.H.

    1995-01-01

    VICTORIA-92 is a mechanistic computer code for analyzing fission product behavior within the reactor coolant system (RCS) during a severe reactor accident. It provides detailed predictions of the release of radionuclides and nonradioactive materials from the core and transport of these materials within the RCS. The modeling accounts for the chemical and aerosol processes that affect radionuclide behavior. Coupling of detailed chemistry and aerosol packages is a unique feature of VICTORIA; it allows exploration of phenomena involving deposition, revaporization, and re-entrainment that cannot be resolved with other codes. The purpose of this work is to determine the attenuation of fission products in the RCS and on the secondary side of the steam generator in an accident initiated by a steam generator tube rupture (SGTR). As a class, bypass sequences have been identified in NUREG-1150 as being risk dominant for the Surry and Sequoyah pressurized water reactor (PWR) plants

  13. Hospital capacity and management preparedness for pandemic influenza in Victoria.

    Dewar, Ben; Barr, Ian; Robinson, Priscilla

    2014-04-01

    This study was designed to investigate acute hospital pandemic influenza preparedness in Victoria, Australia, particularly focussing on planning and management efforts. A prospective study was conducted by questionnaire and semi-structured interview of health managers across the Victorian hospital system from July to October 2011. Participants with responsibility for emergency management, planning and operations were selected from every hospital in Victoria with an emergency department to complete a questionnaire (response rate 22/43 = 51%). Each respondent was invited to participate in a phone-based semi-structured interview (response rate 11/22 = 50%). Rural/regional hospitals demonstrated higher levels of clinical (86%) and non-clinical (86%) staff contingency planning than metropolitan hospitals (60% and 40% respectively). Pandemic plans were not being sufficiently tested in exercises or drills, which is likely to undermine their effectiveness. All respondents reported hand hygiene and standard precautions programs in place, although only one-third (33%) of metropolitan respondents and no rural/regional respondents reported being able to meet patient needs with high levels of staff absenteeism. Almost half Victoria's healthcare workers were unvaccinated against influenza. Hospitals across Victoria demonstrated different levels of influenza pandemic preparedness and planning. If a more severe influenza pandemic than that of 2009 arose, Victorian hospitals would struggle with workforce and infrastructure problems, particularly in rural/regional areas. Staff absenteeism threatens to undermine hospital pandemic responses. Various strategies, including education and communication, should be included with in-service training to provide staff with confidence in their ability to work safely during a future pandemic. © 2014 The Authors. ANZJPH © 2014 Public Health Association of Australia.

  14. A survey of ichthyofauna of Lake Kanyaboli and other small waterbodies in Kenya: alternative refugia for endangered fish species

    Maithya, J.

    1998-01-01

    In 1988, the World Conservation Union (WCU) Red Book of Endangered Species listed hundreds of endemic fishes of Lake Victoria under a single heading - "ENDANGERED". Most of the endemic native food fishes are either endangered or extinct. However, a survey of the fauna of Lake Kanyaboli, revealed that a few remaining samples of these native fishes are actually thriving. These include several unidentified Haplochromis spp., Oreochromis esculentus and Oreochromis variabilis. As a resul...

  15. State Electricity Commission of Victoria annual report 1983-1984

    1984-01-01

    The State Electricity Commission of Victoria (SECV) generates, transmits and distributes electricity throughout Victoria's 228,000 square kilometres and supplies directly to 1.390 million customers. In addition, 278,500 customers are supplied by eleven municipal authorities which purchase electricity in bulk from the Commission. The Commission also has a responsibility to ensure the safe use of electricity. The Commission's mission statement is 'to provide cost effective energy and services and to act at all times in the best interests of the people of Victoria by being a responsible, adaptive, financially sound and efficient public utility'. The mission statement is the foundation for all activities and should provide the Commission with a sense of direction and unity of purpose. Corporate objectives have been developed in the following seven broad areas: customer, employee, finance, natural resources, environment, conservation and community. Each objective has been translated into a series of specific goals, the achievement of which will be monitored. Details relating to these areas of activity are detailed in this report.

  16. Glacier Mass Changes of Lake-Terminating Grey and Tyndall Glaciers at the Southern Patagonia Icefield Derived From Geodetic Observations and Energy and Mass Balance Modeling

    Stephanie S. Weidemann

    2018-06-01

    Full Text Available In this study we demonstrate how energy and mass fluxes vary in space and time for Grey and Tyndall glaciers at the Southern Patagonia Icefield (SPI. Despite the overall glacier retreat of most Patagonian glaciers, a recent increase in mass loss has been observed, but individual glaciers respond differently in terms of spatial and temporal changes. In this context, the detailed investigation of the effect of mass balance processes on recent glacier response to climate forcing still needs refinement. We therefore quantify surface energy-fluxes and climatic mass balance of the two neighboring glaciers, Grey and Tyndall. The COupled Snow and Ice energy and MAss balance model COSIMA is applied to assess recent surface energy and climatic mass balance variability with a high temporal and spatial resolution for a 16-year period between April 2000 and March 2016. The model is driven by downscaled 6-hourly atmospheric data derived from ERA-Interim reanalysis and MODIS/Terra Snow Cover and validated against ablation measurements made in single years. High resolution precipitation fields are determined by using an analytical orographic precipitation model. Frontal ablation is estimated as residual of climatic mass balance and geodetic mass balance derived from TanDEM-X/SRTM between 2000 and 2014. We simulate a positive glacier-wide mean annual climatic mass balance of +1.02 ± 0.52 m w.e. a−1 for Grey Glacier and of +0.68 ± 0.54 m w.e. a−1 for Tyndall Glacier between 2000 and 2014. Climatic mass balance results show a high year to year variability. Comparing climatic mass balance results with previous studies underlines the high uncertainty in climatic mass balance modeling with respect to accumulation on the SPI. Due to the lack of observations accumulation estimates differ from previous studies based on the methodological approaches. Mean annual ice loss by frontal ablation is estimated to be 2.07 ± 0.70 m w.e. a−1 for Grey Glacier and 3.26 ± 0

  17. The Lake and the City

    Konstantin Lidin

    2013-09-01

    Full Text Available The article considers relations between the city of Irkutsk and Lake Baikal in terms of cultural geography. Baikal is included in the UNESCO world heritage list. Unlike the majority of lakes also included in this list, Baikal’s coast is inhabited, especially its southern part. Similar situation is, for example, in the cluster “the city of Bergen – Geiranger village – Geirangerfjord” in Norway. The comparative analysis shows how Norway’s positive experience of the system “a city – a village – a natural phenomenon” could be used in order to make Irkutsk more attractive for tourists and citizens.

  18. Culicídeos do lago de Itaipu, no rio Paraná, Sul do Brasil Culicidae of Itaipu lake, Paraná River, southern Brazil

    Ueslei Teodoro

    1995-02-01

    Full Text Available De janeiro a dezembro de 1991 foram realizadas capturas mensais de culicídeos, no Município de Guaíra, Estado do Paraná (Brasil, na margem esquerda do lago de Itaipu, ao lado da via de acesso que conduzia aos Saltos das Sete Quedas, usando-se armadilha luminosa de Shannon, e isca humana em área urbanizada. Obtiveram-se informações sobre a fauna culicidiana, as espécies prevalentes, a variação sazonal, o horário de maior densidade e a afinidade dos mosquitos em relação ao hospedeiro humano. Foram identificadas 41 espécies de culicídeos dos gêneros Anopheles, Aedes, Aedomyia, Coquillettidia, Culex, Mansonia, Psorophora e Uranotaenia. Capturaram-se 21.280 mosquitos em armadilha de Shannon e 1.010 em isca humana. As espécies mais freqüentes em armadilha de Shannon - Coquillettidia shannoni, Mansonia humeralis, Anopheles triannulatus, Aedes scapularis e Anopheles albitarsis - perfizeram 82,78% dos mosquitos capturados. Em isca humana Aedes scapularís, Mansonia humeralis e Anopheles albitarsis, somaram 91,21% dos insetos capturados. Em armadilha de Shannon o horário de maior atividade das espécies prevalentes foi entre 19 e 22 h. Em isca humana Aedes scapularis teve maior densidade das 20 às 21 h, enquanto Mansonia humeralis e Anopheles albitarsis prevaleceram das 18 às 19 h. Dentre as espécies prevalentes em armadilha de Shannon, Coquillettidia shannoni, Mansonia humeralis e Anopheles albitarsis tiveram pico de atividade no mês de abril, Anopheles triannulatus em janeiro e Aedes scapularis em fevereiro.Mosquito catches were made in Guaíra county, Paraná State, southern Brazil, in the vicinity of Itaipu dam, from January to December 1991. The catches were made with a Shannon light trap and human bait. The Shannon light trap was installed beside the highway that used, formerly, to lead to the Sete Quedas cataracts and the human bait was used in the urban area. Data about the Culicidae fauna were obtained as to predominant

  19. Distribuição, dominância e estrutura de tamanhos da assembleia de peixes da lagoa Mangueira, sul do Brasil Distribution, dominance and sizes structure of the fish assemblage in the Mangueira lake, southern Brazil

    Luiz G. S Artioli

    2009-12-01

    écies entre as porções norte e sul da lagoa. As 52 espécies registradas neste estudo representam uma alta riqueza de peixes na lagoa Mangueira, sobretudo quando comparada a outras lagoas costeiras do RS. Padrões diferenciados de composição e abundância de espécies parecem refletir características distintas dos habitats litorâneos amostrados.This study presents the composition of species, the distribution and dominance patterns, and the structure of sizes of the assemblage of fish in distinct habitats (littoral, deeper and near shore limnetic zone of the Mangueira lake, in the southern Brazil. Samples were taken in the north, south and central regions of the lake from 2001 to 2007 using a multi-gear approach (gillnet, cast net, beach seine, dip net and bottom trawling. A total of 52 species were identified, 46 in the littoral zone, 33 in the near shore limnetic zone and 26 in the deep zone, distributed in 17 families, of the which, Characidae, Cichlidae, Loricariidae, and Atherinopsidae were the most diverse. The dominant species summed up 91.1 %, 92.9 % and 82.7 % of the all individuals caught in the littoral, deeper and limnetic zone, respectively. The littoral zone was comprised of small fishes, nearly 70 % between 25 and 50 TL mm. The dominance patterns showed that, in this zone, 19,5 % of the species were dominant, although four of those also prevailed in the other zones. In the deep zone, 7,6% of the captured species were dominant, with similar sizes to the littoral zone. For the other species, the sizes resemble to the near shore limnetic zone. The near shore limnetic zone was comprised of larger fishes, the major part between 150 and 200 TL mm, such as the great characins, the toothless characin and the silverside fishes. A larger difference was observed in the composition of species between the littoral and limnetic zones, with the species Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii and Gymnogeophagus gymnogenys dominating

  20. A Baseline Air Quality Assessment Onboard a Victoria Class Submarine: HMCS Windsor

    Severs, Y. D

    2006-01-01

    .... This trial thus represents a baseline habitability evaluation of Canada's Victoria class submarines to confirm compliance with the current maximum permissible contaminant limits stipulated in the Air...

  1. A Synoptic Climatology of Heavy Rain Events in the Lake Eyre and Lake Frome Catchments

    Michael John Pook

    2014-11-01

    Full Text Available The rare occasions when Lake Eyre in central, southern Australia fills with water excite great interest and produce major ecological responses. The filling of other smaller lakes such as Lake Frome, have less impact but can contribute important information about the current and past climates of these arid regions. Here, the dominant synoptic systems responsible for heavy rainfall over the catchments of Lake Eyre and Lake Frome since 1950 are identified and compared. Heavy rain events are defined as those where the mean catchment rainfall for 24 hours reaches a prescribed threshold. There were 25 such daily events at Lake Eyre and 28 in the Lake Frome catchment. The combination of a monsoon trough at mean sea level and a geopotential trough in the mid-troposphere was found to be the synoptic system responsible for the majority of the heavy rain events affecting Lake Eyre and one in five of the events at Lake Frome. Complex fronts where subtropical interactions occurred with Southern Ocean fronts also contributed over 20% of the heavy rainfall events in the Frome catchment. Surface troughs without upper air support were found to be associated with 10% or fewer of events in each catchment, indicating that mean sea level pressure analyses alone do not adequately capture the complexity of the heavy rainfall events. At least 80% of the heavy rain events across both catchments occurred when the Southern Oscillation Index (SOI was in its positive phase, and for Lake Frome, the SOI exceeded +10 on 60% of occasions, suggesting that the background atmospheric state in the Pacific Ocean was tilted towards La Niña. Hydrological modeling of the catchments suggests that the 12-month running mean of the soil moisture in a sub-surface layer provides a low frequency filter of the precipitation and matches measured lake levels relatively well.

  2. Lake Cadagno

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur...... cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

  3. Playa Lakes

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  4. A critical review of the development, current hotspots, and future directions of Lake Taihu research from the bibliometrics perspective.

    Zhang, Yunlin; Yao, Xiaolong; Qin, Boqiang

    2016-07-01

    Lake Taihu, as the important drinking water source of the Yangtze River Delta urban agglomeration and the third largest freshwater lake in China, has experienced serious lake eutrophication and water quality deterioration in the past three decades. Growing scientific, political, and public attention has been given to the water quality of Lake Taihu. This study aimed to conduct a comparative quantitative and qualitative analysis of the development, current hotspots, and future directions of Lake Taihu research using a bibliometric analysis of eight well-studied lakes (Lake Taihu, Lake Baikal, Lake Biwa, Lake Erie, Lake Michigan, Lake Ontario, Lake Superior and Lake Victoria) around the world based on the Science Citation Index (SCI) database. A total of 1582 papers discussing Lake Taihu research were published in 322 journals in the past three decades. However, the first paper about Lake Taihu research was not found in the SCI database until 1989, and there were only zero, one, or two papers each year from 1989 to 1995. There had been rapid development in Lake Taihu research since 1996 and a sharp increase in papers since 2005. A keyword analysis showed that "sediment," "eutrophication", "Microcystis aeruginosa", "cyanobacterial blooms", and "remote sensing" were the most frequently used keywords of the study subject. Owing to its significant impact on aquatic ecosystems, a crucial emphasis has been placed on climate change recently. In addition, the future focuses of research directions, including (1) environmental effects of physical processes; (2) nutrient cycles and control and ecosystem responses; (3) cyanobacteria bloom monitoring, causes, forecast and management; (4) eutrophication and climate change interactions; and (5) ecosystem degradation mechanism and ecological practice of lake restoration, are presented based on the keyword analysis. Through multidisciplinary fields (physics, chemistry, and biology) cross and synthesis study of Lake Taihu, the

  5. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield

    Mark C. Gabriel; Randy Kolka; Trent Wickman; Ed Nater; Laurel. Woodruff

    2009-01-01

    The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue...

  6. Increasing deaths involving oxycodone, Victoria, Australia, 2000-09.

    Rintoul, Angela C; Dobbin, Malcolm D H; Drummer, Olaf H; Ozanne-Smith, Joan

    2011-08-01

    In light of an emerging epidemic identified in the United States and Canada, to identify trends in fatal drug toxicity involving oxycodone and the demographic characteristics and indicators of socioeconomic disadvantage of the deceased. Population-based observational study in Victoria, Australia. Decedents whose death was reported to the Victorian Coroner between 2000 and 2009 and where oxycodone was detected. Association between supply of oxycodone and deaths. Demographic characteristics of decedents. Rate ratios of the rural or metropolitan location and socioeconomic indicators of disadvantage of the deceased. Supply to Victoria has increased nine-fold from 7.5 mg per capita in 2000 to 67.5 mg per capita in 2009. Detection of oxycodone in deaths reported to the Victorian Coroner has increased from 4 (0.08/100,000 population) in 2000 to 97 (1.78/100,000 population) in 2009-a 21-fold increase in deaths. Of the 320 cases described, 53.8% (172) were the result of drug toxicity. Of these, 52.3% were unintentional and 19.8% intentional self-harm; the remaining 27.9% are either still under investigation by the coroner or intent is unknown. Drug toxicity deaths were overrepresented in both rural areas and areas indexed with high levels of disadvantage. The substantial increase in the number of deaths involving oxycodone is strongly and significantly associated with the increase in supply. Most drug toxicity deaths involving oxycodone were unintentional. This newly identified trend in fatalities in Victoria supports concerns that a pattern of increasing deaths involving oxycodone is emerging globally.

  7. Reforming Victoria's primary health and community service sector: rural implications.

    Alford, K

    2000-01-01

    In 1999 the Victorian primary care and community support system began a process of substantial reform, involving purchasing reforms and a contested selection process between providers in large catchment areas across the State. The Liberal Government's electoral defeat in September 1999 led to a review of these reforms. This paper questions the reforms from a rural perspective. They were based on a generic template that did not consider rural-urban differences in health needs or other differences including socio-economic status, and may have reinforced if not aggravated rural-urban differences in the quality of and access to primary health care in Victoria.

  8. A recovery-based outreach program in rural Victoria.

    Prabhu, Radha; Browne, Mark Oakley

    2007-04-01

    A recovery-based outreach program for people with severe mental illness in regional Victoria is described. The paper covers a description of the program, the services provided and outcomes achieved. The program emphasized active collaboration between patients and clinicians as outlined in the collaborative recovery model and recognized that recovery from mental illness is an individual, personal process. The program provided service to 108 people over 3 years and had a positive impact on clinicians, patients and carers. The benefits of recovery orientation, multidisciplinary teams, collaborative relationships and carer involvement are discussed. The paper highlights the need for a focus on recovery and comprehensive care for people with severe mental illness.

  9. Royal Ageing: The Queen Mother and Queen Victoria

    Mike Hepworth

    2002-01-01

    This paper is a reflection on the contribution of the image of the Queen Mother to the cultural construction of role models of positive ageing. The interest lies in the Queen Mother's performance in public of her roles as woman and royal personage particularly as she grew older. It is suggested that cultural analysis of the icon of the Queen Mother as a blend of gender and power suggests certain significant parallels with the imagery cultivated around the career of Queen Victoria in the later...

  10. Radon in an underground cave system in Victoria

    Hedt, J.C.; Boal, T.J.

    1998-01-01

    Radon levels in a cave system in Victoria have been measured. The variation of radon and radon progeny levels with time, position throughout the cave and season have been determined. The radiation exposure of tour guides were estimated. The data is being used to develop a radiation management plan for the tour guides. Radon concentration within a cave system was proven to be dependent to a large extent upon the rate of air exchange with outside. Cave ventilation is the single most important factor in determining if there is diurnal variation in the radon concentration

  11. Measuring the cost of leaving care in Victoria

    Catherine Forbes; Brett Inder; Sunitha Raman

    2006-01-01

    On any given night in Victoria, around 4,000 children and young people live under the care and protection of the State. For many young people, this care extends over a long period of time, sometimes until their 18th birthday. It is well documented that young people leaving State care often lack the social and economic resources to assist them in making the transition into independent living. As a consequence, the long-term life outcomes from this group are frequently very poor. A recent repor...

  12. Investigation of landscape and lake acidification relationships

    Rush, R.M.; Honea, R.B.; Krug, E.C.; Peplies, R.W.; Dobson, J.E.; Baxter, F.P.

    1985-10-01

    This interim report presents the rationale and initial results for a program designed to gather and analyze information essential to a better understanding of lake acidification in the northeastern United States. The literature pertinent to a study of landscape and lake acidification relationships is reviewed and presented as the rationale for a landscape/lake acidification study. The results of a study of Emmons Pond in northwestern Connecticut are described and lead to the conclusion that a landscape change was a contributor to the acidification of this pond. A regional study of sixteen lakes in southern New England using Landsat imagery is described, and preliminary observations from a similar study in the Adirondack Mountains are given. These results indicate that satellite imagery can be useful in identifying types of ground cover important to landscape/lake acidification relationships.

  13. affect rice in integrated rice-fish culture in Lake Victoria Basin, Kenya?

    AGHOGHO A

    Rice field ecology and fish culture - an overview. Hydrobiologia 259:91-113. Fernando CH, Halwart M (2000). Fish farming in irrigation systems. Fisheries Management and Ecol. 7:45-54. Frei M, Razzak MA, Hossain MM, Ochme M, Dewan S, Becker K. (2007). Performance of common carp, Cyprinus carpio L. and Nile.

  14. Fingerponds: managing nutrients and primary productivity for enhanced fish production in Lake Victoria's wetlands, Uganda

    Kaggwa, R.S.

    2006-01-01

    Wetlands are of great ecological importance and have been described as the most important zone for freshwater fisheries. They can be exploited for agriculture and aquaculture through the integration of these activities. In Sub-Saharan Africa, emphasis has been put on agriculture and this has 1ed to

  15. Spatial modelling of arsenic distribution and human health effects in Lake Victoria basin, Tanzania

    Ijumulana, Julian; Mtalo, Felix; Bhattacharya, Prosun

    2016-04-01

    Increasing incidences of naturally occurring geogenic pollutants in drinking water sources and associated human health risks are the two major challenges requiring detailed knowledge to support decision making process at various levels. The presence, location and extent of environmental contamination is needed towards developing mitigation measures to achieve required standards. In this study we are developing a GIS-based model to detect and predict drinking water pollutants at the identified hotspots and monitor its variation in space. In addition, the mobility of pollutants within the affected region needs to be evaluated using topographic and hydrogeological data. Based on these geospatial data on contaminant distribution, spatial relationship of As and F contamination and reported human health effects such as dental caries, dental fluorosis, skeletal fluorosis and bone crippling, skin and other cancers etc. can be modeled for potential interventions for safe drinking water supplies.

  16. Biogenic Silica and Carbon 14 Age Dates from Lake Victoria Cruise V95 Cores

    National Oceanic and Atmospheric Administration, Department of Commerce — The LLO operates in conjunction with the Limnological Research Center (LRC) in working towards fulfilling the objectives of the International Decade for the East...

  17. Principles of lake sedimentology

    Janasson, L.

    1983-01-01

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

  18. Integration of altimetric lake levels and GRACE gravimetry over Africa: Inferences for terrestrial water storage change 2003-2011

    Moore, P.; Williams, S. D. P.

    2014-12-01

    Terrestrial water storage (TWS) change for 2003-2011 is estimated over Africa from GRACE gravimetric data. The signatures from change in water of the major lakes are removed by utilizing kernel functions with lake heights recovered from retracked ENVISAT satellite altimetry. In addition, the contribution of gravimetric change due to soil moisture and biomass is removed from the total GRACE signal by utilizing the GLDAS land surface model. The residual TWS time series, namely groundwater and the surface waters in rivers, wetlands, and small lakes, are investigated for trends and the seasonal cycle using linear regression. Typically, such analyses assume that the data are temporally uncorrelated but this has been shown to lead to erroneous inferences in related studies concerning the linear rate and acceleration. In this study, we utilize autocorrelation and investigate the appropriate stochastic model. The results show the proper distribution of TWS change and identify the spatial distribution of significant rates and accelerations. The effect of surface water in the major lakes is shown to contribute significantly to the trend and seasonal variation in TWS in the lake basin. Lake Volta, a managed reservoir in Ghana, is seen to have a contribution to the linear trend that is a factor of three greater than that of Lake Victoria despite having a surface area one-eighth of that of Lake Victoria. Analysis also shows the confidence levels of the deterministic trend and acceleration identifying areas where the signatures are most likely due to a physical deterministic cause and not simply stochastic variations.

  19. Angora Fire, Lake Tahoe

    2007-01-01

    On the weekend of June 23, 2007, a wildfire broke out south of Lake Tahoe, which stretches across the California-Nevada border. By June 28, the Angora Fire had burned more than 200 homes and forced some 2,000 residents to evacuate, according to The Seattle Times and the Central Valley Business Times. On June 27, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the burn scar left by the Angora fire. The burn scar is dark gray, or charcoal. Water bodies, including the southern tip of Lake Tahoe and Fallen Leaf Lake, are pale silvery blue, the silver color a result of sunlight reflecting off the surface of the water. Vegetation ranges in color from dark to bright green. Streets are light gray, and the customary pattern of meandering residential streets and cul-de-sacs appears throughout the image, including the area that burned. The burn scar shows where the fire obliterated some of the residential areas just east of Fallen Leaf Lake. According to news reports, the U.S. Forest Service had expressed optimism about containing the fire within a week of the outbreak, but a few days after the fire started, it jumped a defense, forcing the evacuation of hundreds more residents. Strong winds that had been forecast for June 27, however, did not materialize, allowing firefighters to regain ground in controlling the blaze. On June 27, authorities hoped that the fire would be completely contained by July 3. According to estimates provided in the daily report from the National Interagency Fire Center, the fire had burned 3,100 acres (about 12.5 square kilometers) and was about 55 percent contained as of June 28. Some mandatory evacuations remained in effect. NASA image by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  20. Factors controlling hydrochemical and trophic state variables in 86 shallow lakes in Europe

    Nõges, P.; Nõges, T.; Tuvikene, L.; Smal, H.; Ligeza, S.; Kornijów, R.; Peczula, W.; Bécares, E.; Garcia-Criado, F.; Alvarez-Carrera, C.; Fernandez-Alaez, C.; Ferriol, C.; Miracle, R.M.; Vicente, E.; Romo, S.; Van Donk, E.; Van de Bund, W.J.; Jensen, J.P.; Gross, E.M.; Hansson, L-A.; Gyllström, M.; Nykänen, M.; De Eyto, E.; Irvine, K.; Stephen, D.; Collings, S.E.; Moss, B.

    2003-01-01

    In order to disentangle the causes of variations in water chemistry among European shallow lakes, we performed standardised sampling programs in 86 lakes along a latitudinal gradient from southern Spain to northern Sweden. Lakes with an area of 0.1 to 27 000 ha and mean depth of 0.4–5.6 m located in

  1. Eesti NATO Ühing juurutab demokraatlikke väärtusi / Victoria Punga ; interv. Aive Antsov

    Punga, Victoria, 1977-

    2007-01-01

    Eesti NATO Ühingu tegevjuht organisatsiooni eesmärkidest, projektidest, koostööst teiste riikidega ning kaitsepoliitika ja majanduse seostest. Lisa: Väljavõte Victoria CVst; Eesti kaitsepoliitika viis plussi Victoria meelest

  2. Victoria suudlus teeb maapoisist printsi, kuid mitte tulevase kuninga / Kaivo Kopli

    Kopli, Kaivo

    2010-01-01

    Printsess Victoria tulevasest abikaasast Daniel Westlingist, printsess Madelaine'i kihluse lõpetamisest, Bernadotte'ide dünastia asutajast Jean Bernadotte'ist. Monarhia toetajate vähenemisest Rootsis. Printsess Victoria ja Daniel Westlingi pulmatseremooniast 19. juunil

  3. 78 FR 48318 - Approval and Promulgation of Air Quality Implementation Plans; Texas; Victoria County, 1997 8...

    2013-08-08

    ... pollution. Inclusion of Victoria County in 30 TAC Chapter 115 volatile organic compounds (VOC) rules for the... vessels, and marine vessels would be required to vent to a control device until the VOC concentration of... Victoria County in 30 TAC Chapter 114 rule for Texas Low Emission Diesel (TxLED) compliant marine diesel...

  4. Formula-Based Public School Funding System in Victoria: An Empirical Analysis of Equity

    Bandaranayake, Bandara

    2013-01-01

    This article explores the formula-based school funding system in the state of Victoria, Australia, where state funds are directly allocated to schools based on a range of equity measures. The impact of Victoria' funding system for education in terms of alleviating inequality and disadvantage is contentious, to say the least. It is difficult to…

  5. Informal waste harvesting in Victoria Falls town, Zimbabwe: Socio-economic benefits

    Masocha, M.

    2006-01-01

    Waste harvesting, which occurs mostly but not exclusively at open waste dumps in Zimbabwe, constitutes one of the most important survival options for the urban poor. This paper analyses and discusses socio-economic benefits of informal waste harvesters in Victoria Falls town. Victoria Falls town has

  6. Genetic analyses of resistance against Leptopilina victoriae in Drosophila bipectinata.

    Takigahira, Tomohiro; Kohyama, Tetsuo I; Suwito, Awit; Kimura, Masahito T

    2015-06-01

    Drosophila bipectinata from Iriomote-jima (IR) is susceptible to the endoparasitoid Leptopilina victoriae from Kota Kinabalu (L. victoriae KK), but D. bipectinata from Kota Kinabalu (KK) and Bogor (BG) is resistant. The cross experiments between the resistant (KK) and susceptible (IR) populations of D. bipectinata suggested that the resistance to this parasitoid is a dominant trait and controlled by a single locus or few linked loci on an autosome. In the AFLP analysis using the IR, KK and BG populations of D. bipectinata and the resistant and susceptible populations derived from a mixed population of these three geographic populations, a DNA fragment almost specific to susceptible flies was detected. It also revealed that genes from the IR population were more frequently maintained in the mixed population compared with those from the KK and BG populations, suggesting that at least a number of genes from the IR population are more advantageous under the laboratory conditions. This explains our previous results that the resistance was lowered in the mixed population although the resistance itself is suggested to incur only low costs; i.e., the resistance gene(s) from the KK and BG populations would have been linked with some genes that are disadvantageous under the laboratory conditions.

  7. Surviving neoliberalism, maintaining values: Community health mergers in Victoria, Australia.

    Roussy, Véronique; Livingstone, Charles

    2018-04-01

    Independent, not-for-profit community health services in the state of Victoria, Australia, provide one of that country's few models of comprehensive primary health care (PHC). Recent amalgamations among some such agencies created regional-sized community health organisations, in a departure from this sector's traditionally small local structure. This study explored the motivations, desired outcomes, and decision-making process behind these mergers. Qualitative exploratory study was based on 26 semistructured interviews with key informants associated with 2 community health mergers, which took place in 2014 in Victoria, Australia. Thematic data analysis was influenced by concepts derived from institutional theory. Becoming bigger by merging was viewed as the best way to respond to mounting external pressures, such as increasingly neoliberal funding mechanisms, perceived as threatening survival. Desired outcomes were driven by comprehensive PHC values, and related to creating organisational capacity to continue providing quality services to disadvantaged communities. This study offers insights into decision-making processes geared towards protecting the comprehensiveness of PHC service delivery for disadvantaged communities, ensuring financial viability, and surviving neoliberal economic policy whilst preserving communitarian values. These are relevant to an international audience, within a global context of rising health inequities, increasingly tight fiscal environments, and growing neoliberal influences on health policymaking and funding. Copyright © 2018 John Wiley & Sons, Ltd.

  8. VICTORIA PARK: A DEMOCTRATIC PUBLIC OPEN SPACE FOR INDONESIA DOMESTIC HELPERS (TKW

    Parmonangan Manurung

    2016-01-01

    Full Text Available Victoria Park is the largest city park in Hong Kong. This city park is not only known in Hong Kong, but also very well known in Indonesia as a gathering place for Indonesia domestic helpers (TKW in Hong Kong. This research tried to find out some determinant factors that have been affected the public open spac of Victoria Park to be a gathering place for thousands of TKW in Sunday and holidays as their day off. In order to get the results of research, some methodological research had been conducted such as: observation (survey, mapping, interviews and literature studies. The results showed that Victoria Park has a number of factors capable of meeting the needs of domestic help-ers in Hong Kong, these factors consist of internal factors and external factors. Internally, the character and functions held Victoria Park became a very influential factor, while externally, the accessibility and support functions around Victoria Park also has a considerable influence.

  9. Nearshore Placement Techniques in Southern Lake Michigan

    2018-03-01

    of water in small discrete mounds to prevent the sediment from obstructing the hanging gates of the scow from closing. The sediment will be...mobilized more frequently, and more energy will be dissipated if the dredged sediment is placed in shallower depths in the shape of an elongated bar or...Acting Chief, CEERD-HN-C, and Mr. Charles E. Wiggins was Acting Chief, CEERD-HN. Ms. Linda S. Lillycrop, CEERD-HN-C, was the USACE National RSM

  10. Great Lakes

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

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  11. Monitoring of Heavy Metal Loading into the Wetlands South of Lake ...

    Wetlands impacted by gold mining activities in the South Lake Victoria basin show elevated heavy metal contents in soil and sediment, particularly Cu (13-415 mg/kg), Pb (24-94 mg/kg), Zn (9-80 mg/kg), Cr (19-77 mg/kg), Ni (12-37 mg/kg) and Hg (0.19-1.76 mg/kg), contrary to non-impacted wetlands, which contain ...

  12. Granitoids of the Dry Valleys area, southern Victoria Land, Antarctica : plutons, field relationships, and isotopic dating

    Allibone, A.H.; Cox, S.C.; Johnstone, R.D.

    1993-01-01

    Detailed mapping throughout much of the Dry Valleys area indicates the region is underlain by 15 major granitoid plutons and numerous smaller plugs and dikes. Intrusive relationships of these plutons and dikes indicate repeated intrusion of superficially similar granitoids at different times. Sufficient internal lithologic variation occurs within individual plutons, to allow correlation with several of the previously defined granitoid units based on lithologic character. Consequently, previous subdivision schemes based on lithology are no longer tenable and are here replaced with a subdivision scheme based on the identification of individual plutons. The elongate, concordant Bonney, Denton, Cavendish, and Wheeler Plutons, which range in composition between monzodiorite and granodiorite, are the oldest relatively undeformed plutons in the Dry Valleys area. Each pluton is characterised by flow alignment of K-feldspar megacrysts, hornblende, biotite, and mafic enclaves. Field relationships and radiometric dating indicate these are deep-level plutons, emplaced synchronous with upper amphibolite facies metamorphism of the adjacent Koettlitz Group between 589 and 490 Ma ago. Elongate, discordant plutons of equigranular homogeneous biotite granodiorite and granite (Hedley, Valhalla, St Johns, Suess) were subsequently emplaced by stoping at a relatively high crustal level at 490 Ma. These eight plutons are cut by numerous swarms of Vanda mafic and felsic porphyry dikes. The ovoid, discordant, high level Pearse, Nibelungen, Orestes, Brownworth, Swinford, and Harker Plutons, emplaced between c. 486 and 477 Ma, display mutually crosscutting relationships with the youngest of the Vanda dikes. These younger plutons range in composition between monzonite and granite. Some are characterised by K-feldspar megacrystic textures superficially similar to some of the oldest concordant plutons. (author). 57 refs.; 2 tabs.; 4 figs

  13. Panorama Pluton : a composite gabbro-monzodiorite early Ross Orogeny intrusion in southern Victoria Land, Antarctica

    Mellish, S.D.; Cooper, A.F.; Walker, N.W.

    2002-01-01

    The Koettlitz Glacier Alkaline Province of the Walcott Glacier to Radian Glacier area of the Transantarctic Mountains contains a diverse suite of intrusions ranging from gabbro and diorite to granite, nepheline syenite, and carbonatite. Most of the plutons are alkaline (A-type), although the Panorama Pluton is mafic, comprising both hypersthene normative gabbroic and quartz normative monzodioritic lithologies. The pluton has a composite nature, determined by whole-rock geochemical trends and Nd-Sr isotope data that reflect distinctive source regions for the different components. U-Pb geochronology of zircon and titanite indicates the Panorama Pluton was intruded during the early stages of the Neoproterozoic-early Paleozoic Ross Orogeny at 535 ± 9 Ma, and that it is coeval with the geochemically similar Dromedary Mafic Complex which crops out 10 km to the southeast. The Panorama Pluton is a volumetrically minor mafic component of the Koettlitz Glacier Alkaline Province, which predates, by at least 15 m.y., the dominant calc-alkaline suites that occur along-strike in the Dry Valleys area to the north, and the central Transantarctic Mountains to the south. The Panorama Pluton magmas, and other Koettlitz Glacier Alkaline Province lithologies, are interpreted to have formed in an extensional or transtensional jog that predates the onset of widespread Ross Orogeny subduction. (author). 48 refs., 7 figs., 3 tabs

  14. Total organic carbon in pond waters from the Labyrinth of southern Victoria Land in the Antarctic

    松本, 源喜; 綿抜, 邦彦; 鳥居, 鉄也; Genki I., Matsumoto; Kunihiko, Watanuki; Tetsuya, Torii

    1987-01-01

    南極南ビクトリアランド・ライト谷上部のラビリンス(77°33′S, 165°50′E)に分布する, 10個の池の全有機炭素(TOC)を測定した。TOC値は池水間で大きく異なる(0.78-23mgC/l)が, 高濃度のTOCは塩池水のみで測定された。電気伝導度とTOC値間には, かなり高い正の相関(0.82)がみられた。このことは次のように解釈される。1)まず降雪や氷河融水に含まれていた有機物が, 池水の凍結により残液に濃縮される。2)次いで池内の生物生産による有機物が加わるとともに, 容易に微生物分解を受ける有機物が除去される。3)さらに池水の蒸発と凍結が繰り返されることにより, 長年月の間に比較的分解しにくい有機物が, 溶存無機塩類とともに池底付近に蓄積される。...

  15. The food of the lake trout (Cristivomer namaycush namaycush) and of the lawyer (Lota maculosa) of Lake Michigan

    Van Oosten, John; Deason, Hilary J.

    1938-01-01

    This paper reports on a qualitative and quantitative analysis of the contents of 4,979 lake trout stomachs (593 examined in 1930 and 1,253 collected in 1931 from southern Lake Michigan, 1,446 from northern Lake Michigan and 1,687 from Green Bay in 1932), and of a total of 1,528 lawyer stomachs (172 examined in 1930 and 734 collected in 1931 from southern Lake Michigan, 612 from northern Lake Michigan and 10 from Green Bay in 1932). The food of the trout consisted of 98 per cent by volume of fish of which Cottidae and Coregonidae were the principal constituents. Cottidae were dominant in southern Lake Michigan (72 per cent by volume), Coregonidae in northern Lake Michigan (51 per cent) but the lake shiner, Notropis atherinides, was most important in Green Bay in the spring of the year (64 per cent). The lawyer food consisted of 74 per cent by volume of fish and 26 per cent invertebrates. Dominant items were Cottidae (76 per cent by volume) in southern Lake Michigan, Coregonidae (51 per cent) and Pontoporeia (37 per cent) in northern Lake Michigan, and Percopsis (34 per cent) and Mysis (26 per cent) in Green Bay. Data are also presented on the frequency of occurrence (number of stomachs) of the food items and its variation with the sizes of the trout and lawyers, depths of water, seasons, and localities; on the number of individual fish of each species destroyed by the trout and lawyers; and on the calculated volume of the food fishes preceding digestion. The lake trout and lawyer are competitors for the same food, are both predators of the commercially important Coregonidae, and the lawyer through its consumption of invertebrates is a food competitor of the Coregonidae.

  16. CHEMICAL CHARACTERISTICS OF LAKE KIVU, RWANDA Olap

    USER

    2012-08-05

    Aug 5, 2012 ... Forestry, University of Ibadan, Ibadan, Nigeria ... concentration in the lake water does not constitute any serious health risk to both man ..... tropics is adapted. .... personnel and laboratory space used for the research work. .... Water Quality of Angaw River in southern – eastern coastal plains of Ghana. W. Afri ...

  17. Evaluating the spatial variation of total mercury in young-of-year yellow perch (Perca flavescens), surface water and upland soil for watershed-lake systems within the southern Boreal Shield

    Gabriel, M.C.; Kolka, R.; Wickman, T.; Nater, E.; Woodruff, Laurel G.

    2009-01-01

    The primary objective of this research is to investigate relationships between mercury in upland soil, lake water and fish tissue and explore the cause for the observed spatial variation of THg in age one yellow perch (Perca flavescens) for ten lakes within the Superior National Forest. Spatial relationships between yellow perch THg tissue concentration and a total of 45 watershed and water chemistry parameters were evaluated for two separate years: 2005 and 2006. Results show agreement with other studies where watershed area, lake water pH, nutrient levels (specifically dissolved NO3−-N) and dissolved iron are important factors controlling and/or predicting fish THg level. Exceeding all was the strong dependence of yellow perch THg level on soil A-horizon THg and, in particular, soil O-horizon THg concentrations (Spearman ρ = 0.81). Soil B-horizon THg concentration was significantly correlated (Pearson r = 0.75) with lake water THg concentration. Lakes surrounded by a greater percentage of shrub wetlands (peatlands) had higher fish tissue THg levels, thus it is highly possible that these wetlands are main locations for mercury methylation. Stepwise regression was used to develop empirical models for the purpose of predicting the spatial variation in yellow perch THg over the studied region. The 2005 regression model demonstrates it is possible to obtain good prediction (up to 60% variance description) of resident yellow perch THg level using upland soil O-horizon THg as the only independent variable. The 2006 model shows even greater prediction (r2 = 0.73, with an overall 10 ng/g [tissue, wet weight] margin of error), using lake water dissolved iron and watershed area as the only model independent variables. The developed regression models in this study can help with interpreting THg concentrations in low trophic level fish species for untested lakes of the greater Superior National Forest and surrounding Boreal ecosystem.

  18. State Electricity Commission of Victoria annual report 1991/92

    1992-01-01

    The 73rd annual report of the State Electricity Commission (SEC) of Victoria covers the financial year ended 30 June 1992. A total revenue of 3,300 million dollars and a net profit of 155.7 million dollars was recorded. There was continued improvement in employee productivity. Progress was made on the Victorian Power Pool (VicPool) pooling arrangement in anticipation of open access to the power grid. A 3-year business plan was formulated and corporate strategy revised. The Strategic Research Program on brown coal technologies, aimed at reducing costs of electricity and emissions of CO[sub 2], continued. Environmental activities continued in the areas of renewable energy source development, air quality monitoring, acid rain, water management, land rehabilitation and improvements to powerlines. The report includes statistical data on customer statistics, electricity sales, power stations, brown coal and briquette production and financial sales.

  19. Myxomatosis in the Mallee region of Victoria, Australia.

    Shepherd, R C; Edmonds, J W; Nolan, I F; Gocs, A

    1978-10-01

    Sharp reductions in the wild rabbit (Oryctolagus cuniculus (L.)) population in the Mallee are associated with annual myxomatosis epizootics. The extent to which the population reductions are the direct result of the epizootics varies with time of epizootic occurrence. All grazing animals in the Mallee are under nutritional stress each summer and autumn. When the epizootic occurs during the early summer heavy losses occur in a previously healthy population. Similar losses which occur in the late summer and autumn are the result of a nutritional stress - epizootic complex. The end result in each case is a population reduction of about 80%. This reduction occurs in a population which is the most resistant to myxomatosis known in Victoria and in association with epizootics caused by field strains of myxoma virus of moderate virulence only. The earlier summer epizootics are of considerable economic importance because they sharply reduce the pressure on the limited food available for other grazing animals.

  20. The radiocarbon dating project at Aboriginal Affairs, Victoria

    Godfrey, M.C.S.

    1997-01-01

    The purpose of this project has been to publish a complete list of the age estimates relating to the archaeological sites in the State of Victoria from 1951 to 1995, and to assess the value and the limitations of this information for interpreting the prehistory of this region. This project has recorded 476 dates coming from 14 laboratories, and ranging in age from the time of European settlement to the limit of the technique at around 40,000 years BP. However, the available evidence indicates that large discrepancies may exist in these results, and this has lead to the recommendation that this data should not be used in research projects requiring dating accuracies of less than a few hundred years

  1. The State Electricity Commission of Victoria and the greenhouse effect

    Hoy, R.D.

    1990-01-01

    The State Electricity Commission of Victoria is examining how the greenhouse issue may affect its electricity supply system in the future. Possible generation scenarios for 2005 are presented in order to show how the Toronto goal of a 20% reduction on 1988 levels of CO 2 emissions could be achieved. The main approaches to achieving these emission reductions include energy conservation and cogeneration, new gas-fired plant, use of renewable energy, reduction of energy system losses, retirement of older brown coal plant and an extensive tree planting program. It is estimated that achieving the Toronto goal would require electricity prices to rise by 1% to 1.5%, on average, each year by more than they otherwise would have, for the next 15 years. 12 refs., 3 tabs

  2. Layers of 'Cabo Frio' in 'Victoria Crater' (False Color)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  3. Layers of 'Cabo Frio' in 'Victoria Crater' (Stereo)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.

  4. Water and waste water management Generation Victoria - Latrobe Valley

    Longmore, G. [Hazelwood Power Corporation, VIC (Australia); Pacific Power (International) Pty. Ltd., Sydney, NSW (Australia)

    1995-12-31

    Water is a necessary resource for coal fired power plant and waste water is generated. The efficient management of water and waste water systems becomes an important operational environmental factor. This paper describes the development and implementation of a ten year water and waste water management strategy for the Latrobe Valley Group of brown coal fired power stations in Victoria. In early 1991, a team was put together of representatives from each power site to develop the strategy entitled `SECV Latrobe Valley Water and Wastewater Management Strategy`. The strategy was developed with extensive public consultation, which was a factor in protracting the process such that the final document was not promulgated until late 1992. However, the final comprehensive document endorsed and agreed by management, has since attracted favourable comment as a model of its type. (author). 2 figs.

  5. Water and waste water management Generation Victoria - Latrobe Valley

    Longmore, G.

    1995-01-01

    Water is a necessary resource for coal fired power plant and waste water is generated. The efficient management of water and waste water systems becomes an important operational environmental factor. This paper describes the development and implementation of a ten year water and waste water management strategy for the Latrobe Valley Group of brown coal fired power stations in Victoria. In early 1991, a team was put together of representatives from each power site to develop the strategy entitled 'SECV Latrobe Valley Water and Wastewater Management Strategy'. The strategy was developed with extensive public consultation, which was a factor in protracting the process such that the final document was not promulgated until late 1992. However, the final comprehensive document endorsed and agreed by management, has since attracted favourable comment as a model of its type. (author). 2 figs

  6. Productivity changes in the Gas and Fuel Corporation of Victoria

    Rushdi, A.

    1994-01-01

    The study reveals that the total factor productivity in the Gas and Fuel Corporation of Victoria (GFCV) continued to increase throughout the study period except for a brief period between 1983-84 and 1984-85 which was mainly the result of the decline in the industrial demand for gas and a decelerated growth rate in residential demand. The productivity gains were found to be highly sensitive to the rates of depreciation and discount rates assumed. The estimated terms of trade suggest that the increase in gas prices was lower that the increase in the aggregate input prices the GFCV paid, particularly to capital and labour. However, while the price index of reticulated gas increased to 2.17, the purchase price declined to 0.96 over the study period. The productivity gains by GFCV seem to have been shared with its customers. (Author)

  7. Critical Comments on Brian Victoria's "Engaged Buddhism: Skeleton in the Closet?"

    Koichi Miyata

    2015-02-01

    Full Text Available In "Engaged Buddhism: A Skeleton in the Closet?" (Vol. 2 Brian Daizen Victoria claims, among other things, that Tsunesaburo Makiguchi (1871-1944, founder of the Soka Kyoiku Gakkai (forebear of the Soka Gakkai and Soka Gakkai International, was an active supporter of the Japanese wars of aggression. In this response, Koichi Miyata argues that Victoria's claims rest on the highly selective use of quotes, and ignore key interpretative issues associated with Japanese imperial fascism and its underlying belief structures. Miyata discusses the significance of Makiguchi's arrest and imprisonment under a law specifically aimed at opponents of the war efforts, in his analysis of critical lapses in Victoria's article.

  8. The Neogene lakes on the Balkan land

    Krstić Nadežda

    2012-01-01

    Full Text Available Palaeogeographic maps of the lacustrine Miocene and Pliocene have been constructed according to all the known geological data. The Lakes of the Balkan Land, depending on the tectonics, migrated due to causes from the deep subsurface. There are several phases of the Miocene lakes: the lowermost Miocene transiting from marine Oligocene, Lower, Middle, Upper Miocene covering, in patches, the main part of the Land. The Pliocene lakes spread mostly to the north of the Balkan Land and covered only its marginal parts. Other lake-like sediments, in fact freshened parts of the Black Sea Kuialnician (Upper Pliocene, stretched along the middle and southern portions of the Balkan Peninsula (to the south of the Balkan Mt.. Subsequently, the Balkan Peninsula was formed.

  9. Water Resources Data for California, Water Year 1988. Volume 1. Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Polinoski, K.G.; Hoffman, E.B.; Smith, G.B.; Bowers, J.C.

    1989-01-01

    Water resources data for the 1988 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 1 contains discharge records for 134 gaging stations; stage and contents for 17 lakes and reservoirs; and water quality for 24 streams. Also included are 10 crest-stage partial-record stations, 5 miscellaneous measurement sites, and 16 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  10. Water Resources Data for California, Water Year 1987. Volume 1. Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Bowers, J.C.; McConaughy, C.E.; Polinoski, K.G.; Smith, G.B.

    1988-01-01

    Water resources data for the 1987 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 1 contains discharge records for 134 gaging stations; stage and contents for 16 lakes and reservoirs; and water quality for 16 streams. Also included are 10 crest-stage partial-record stations, 3 miscellaneous measurement sites, and 10 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  11. Water Resources Data for California, Water Year 1985. Volume 1. Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Bowers, J.C.; McConaughy, C.E.; Polinoski, K.G.; Smith, G.B.

    1987-01-01

    Water resources data for the 1985 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 1 contains discharge records for 150 gaging stations; stage and contents for 17 lakes and reservoirs; water quality for 23 streams. Also included are 10 crest-stage partial-record stations, three miscellaneous measurement sites, and one waterquality partial-record station. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  12. Water Resources Data for California, water year 1981: Vol. 1. Colorado River basin, Southern Great basin from Mexican Border to Mono Lake basin, and Pacific slope basins from Tijuana River to Santa Maria River

    ,

    1982-01-01

    Water-resources data for the 1981 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 1 contains discharge records for 169 gaging stations; stage and contents for 19 lakes and reservoirs; water quality for 42 streams and 21 wells; water levels for 169 observation wells. Also included are 10 crest-stage partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  13. Water resources data for California, water year 1980; Volume 1, Colorado River basin, Southern Great Basin from Mexican border to Mono Lake basin, and Pacific slope basins from Tijuana River to Santa Maria River

    ,

    1981-01-01

    Volume 1 of water resources data for the 1980 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lake and reservoirs; and water levels in wells. This report contains discharge records for 174 gaging stations; stage and contents for 18 lakes and reservoirs; water quality for 51 stations; water levels for 165 observation wells. Also included are 9 crest-stage partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  14. Water Resources Data for California, Water Year 1986. Volume 1. Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Bowers, J.C.; McConaughy, C.E.; Polinoski, K.G.; Smith, G.B.

    1988-01-01

    Water resources data for the 1986 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 1 contains discharge records for 144 gaging stations; stage and contents for 15 lakes and reservoirs; watet quality for 21 streams. Also included are crest-stage partial-record stations, 3 miscellaneous measurement sites, and 5 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  15. Bathymetry of Lake Michigan

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

  16. Bathymetry of Lake Ontario

    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...

  17. Bathymetry of Lake Superior

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

  18. Great Lakes Bathymetry

    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...

  19. Bathymetry of Lake Huron

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

  20. PREDICTED SEDIMENTARY SECTION OF SUBGLACIAL LAKE VOSTOK

    G. I. Leychenkov

    2012-01-01

    Full Text Available In early February 2012, the drill hole at the Vostok Station encountered theLakeVostokwater. This step is important to study the lake composition including possible microbial life and to model subglacial environments however, the next ambitious target of the Vostok Drilling Project is sampling of bottom sediments, which contain the unique record of ice sheet evolution and environmental changes in centralAntarcticafor millions of years. In this connection, the forecast of sedimentary succession based on existing geophysical data, study of mineral inclusions in the accretion ice cores and tectonic models is important task. Interpretation of Airborne geophysical data suggests thatLakeVostokis the part of spacious rift system, which exists at least from Cretaceous. Reflection and refraction seismic experiments conducted in the southern part ofLakeVostokshow very thin (200–300 m stratified sedimentary cover overlying crystalline basement with velocity of 6.0–6.2 km/s. At present, deposition in southernLakeVostokis absent and similar conditions occurred likely at least last3 m.y. when ice sheet aboveLakeVostokchanged insignificantly. It can be also inferred that from the Late Miocene the rate of deposition inLakeVostokwas extremely low and so the most of sedimentary section is older being possibly of Oligocene to early to middle Miocene age when ice sheet oscillated and deposition was more vigorous. If so, the sampling of upper few meters of this condensed section is very informative in terms of history of Antarctic glaciation. Small thickness of sedimentary cover raises a question about existence of lake (rift depression during preglacial and early glacial times.

  1. Geophysical investigation of sentinel lakes in Lake, Seminole, Orange, and Volusia Counties, Florida

    Reich, Christopher; Flocks, James; Davis, Jeffrey

    2012-01-01

    This study was initiated in cooperation with the St. Johns River Water Management District (SJRWMD) to investigate groundwater and surface-water interaction in designated sentinel lakes in central Florida. Sentinel lakes are a SJRWMD established set of priority water bodies (lakes) for which minimum flows and levels (MFLs) are determined. Understanding both the structure and lithology beneath these lakes can ultimately lead to a better understanding of the MFLs and why water levels fluctuate in certain lakes more so than in other lakes. These sentinel lakes have become important water bodies to use as water-fluctuation indicators in the SJRWMD Minimum Flows and Levels program and will be used to define long-term hydrologic and ecologic performance measures. Geologic control on lake hydrology remains poorly understood in this study area. Therefore, the U.S. Geological Survey investigated 16 of the 21 water bodies on the SJRWMD priority list. Geologic information was obtained by the tandem use of high-resolution seismic profiling (HRSP) and direct-current (DC) resistivity profiling to isolate both the geologic framework (structure) and composition (lithology). Previous HRSP surveys from various lakes in the study area have been successful in identifying karst features, such as subsidence sinkholes. However, by using this method only, it is difficult to image highly irregular or chaotic surfaces, such as collapse sinkholes. Resistivity profiling was used to complement HRSP by detecting porosity change within fractured or collapsed structures and increase the ability to fully characterize the subsurface. Lake Saunders (Lake County) is an example of a lake composed of a series of north-south-trending sinkholes that have joined to form one lake body. HRSP shows surface depressions and deformation in the substrate. Resistivity data likewise show areas in the southern part of the lake where resistivity shifts abruptly from approximately 400 ohm meters (ohm-m) along the

  2. Did the use of chloroform by Queen Victoria influence its acceptance in obstetric practice?

    Connor, H; Connor, T

    1996-10-01

    Examination of contemporaneous publications suggests that the use of chloroform by Queen Victoria in 1853 did not result in the major breakthrough in the acceptability of obstetric anaesthesia with which the event has been credited by some later writers.

  3. Contrasting rainfall declines in northern and southern Tanzania: Potential differential impacts of west Pacific warming and east Pacific cooling

    Harrison, L.; Funk, C. C.; Verdin, J. P.; Pedreros, D. H.; Shukla, S.; Husak, G. J.

    2015-12-01

    Here, we present analysis of a new 1900-2014 rainfall record for the Greater Horn of Africa with high station density (CenTrends), and evaluate potential climate change "hot spots" in Tanzania. We identify recent (1981-2014) downward trends in Tanzanian rainfall, use CenTrends to place these in a longer historical context, and relate rainfall in these regions to decadal changes in global sea surface temperatures (SSTs). To identify areas of concern, we consider the potential food security impacts of the recent rainfall declines and also rapid population growth. Looking forward, we consider what the links to SSTs might mean for rainfall in the next several decades based on SST projections. In addition to CenTrends, we use a variety of geographic data sets, including 1981-2014 rainfall from the Climate Hazards group InfraRed Precipitation with Stations (CHIRPSv2.0), simulated crop stress from the USGS Geospatial Water Requirement Satisfaction Index (GeoWRSI) model, NOAA Extended Reconstructed SSTs (ERSST v4), SST projections from the Coupled Model Intercomparison Project (CMIP5), and land cover and population maps from SERVIR, WorldPOP, and CIESIN's Gridded Population of the World. The long-term CenTrends record allows us to suggest an interesting dichotomy in decadal rainfall forcing. During the March to June season, SSTs in the west Pacific appear to be driving post-1980 rainfall reductions in northern Tanzania. In the 2000s, northern Tanzania's densely populated Pangani River, Internal Drainage, and Lake Victoria basins experienced the driest period in more than a century. During summer, negative trends in southern Tanzania appear linked to a negative SST trend in the Nino3.4 region. Since the SST trend in the west (east) Pacific appears strongly influenced by global warming (natural decadal variability), we suggest that water resources in northern Tanzania may face increasing challenges, but that this will be less the case in southern Tanzania.

  4. Monitoring recent lake level variations on the Tibetan Plateau using CryoSat-2 SARIn mode data

    Jiang, Liguang; Nielsen, Karina; Andersen, Ole Baltazar

    2017-01-01

    are comparable. Lakes in the northern part of the TP experienced pronounced rising (avg. 0.37 ± 0.10 m/yr), while lakes in southern part were steady or decreasing even in glaciated basins with high precipitation. Factor analysis indicates that driving factors for lake change are variable due to high spatial...

  5. Great Lakes Science Center

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  6. Victoria Stodden: Scholarly Communication in the Era of Big Data and Big Computation

    Stodden, Victoria

    2015-01-01

    Victoria Stodden gave the keynote address for Open Access Week 2015. "Scholarly communication in the era of big data and big computation" was sponsored by the University Libraries, Computational Modeling and Data Analytics, the Department of Computer Science, the Department of Statistics, the Laboratory for Interdisciplinary Statistical Analysis (LISA), and the Virginia Bioinformatics Institute. Victoria Stodden is an associate professor in the Graduate School of Library and Information Scien...

  7. Validation of New Crack Monitoring Technique for Victoria Class High-Pressure Air Bottles

    2014-06-01

    Defence Research and Development Canada Recherche et développement pour la défense Canada Validation of new crack monitoring technique for Victoria ...Validation of new crack monitoring technique for Victoria class high-pressure air bottles Ian Thompson John R. MacKay Defence Research and Development...Canada Scientific Report DRDC-RDDC-2014-R81 June 2014 © Her Majesty the Queen in Right of Canada (Department of National Defence), 2014 © Sa Majesté

  8. Analysis of an Organisation: A University of the Third Age (U3A), Mornington, Victoria

    Small, Michael

    2017-01-01

    The purpose of this paper is two fold: to look at Mornington U3A in organisational terms and then look at U3AM as a loosely coupled system. One outcome of the study would be to undertake further analyses of U3As in Victoria to determine the levels of bureaucracy under which each operates. Questions to be asked: are U3As in Victoria operating as…

  9. Las pinturas esquemáticas de la Cueva de Victoria (Rincón de la Victoria, Málaga : propuesta interpretativa del friso A

    Rafael Maura Mijares

    2004-01-01

    Full Text Available Se recoge en este artículo nuestra reciente revisión del conjunto pictórico postpaleolítico de la cueva de la Victoria. A partir de una documentación exhaustiva de los motivos representados y del análisis de su iconografía se proponen hipótesis de carácter interpretativo.In this article we gather the recent revision of the postpalaeolithic pictorial collection in the cave of la Victoria. Starting from an exhaustive documentation of the motifs and the analysis of its iconography, we propose some interpretative hypothesis.

  10. A once in a generation upgrade to ICT systems used for public transport in Victoria; Umfassende Modernisierung. Neue ICT-Systeme fuer den SPNV in Victoria

    Hammerton, Richard [Funkwerk Information Technologies York Ltd., York (United Kingdom)

    2010-07-01

    Funkwerk IT is supplying a state-of-the-art timetable and fleet planning and management system to the Australian State of Victoria. Through its agency, the Department of Transport, Victoria is undertaking a once in a generation upgrade to key ICT systems that are used for operational control of the metropolitan and regional rail networks. The new system requires a tight coupling of both planning and real-time management systems. Using its products TrainPlan, ResourcePlan and ResourceManager Funkwerk IT provides an ideal platform to cover these requirements. (orig.)

  11. Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

    Xing Wang

    2015-06-01

    Full Text Available A Lake Multi-biotic Integrity Index (LMII for the China’s second largest interior lake (Dongting Lake was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P<0.001. The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.

  12. Exploratory studies into seasonal flow forecasting potential for large lakes

    Sene, Kevin; Tych, Wlodek; Beven, Keith

    2018-01-01

    In seasonal flow forecasting applications, one factor which can help predictability is a significant hydrological response time between rainfall and flows. On account of storage influences, large lakes therefore provide a useful test case although, due to the spatial scales involved, there are a number of modelling challenges related to data availability and understanding the individual components in the water balance. Here some possible model structures are investigated using a range of stochastic regression and transfer function techniques with additional insights gained from simple analytical approximations. The methods were evaluated using records for two of the largest lakes in the world - Lake Malawi and Lake Victoria - with forecast skill demonstrated several months ahead using water balance models formulated in terms of net inflows. In both cases slight improvements were obtained for lead times up to 4-5 months from including climate indices in the data assimilation component. The paper concludes with a discussion of the relevance of the results to operational flow forecasting systems for other large lakes.

  13. Lake Cadagno

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

  14. The bone microstructure of polar "hypsilophodontid" dinosaurs from Victoria, Australia.

    Woodward, Holly N; Rich, Thomas H; Vickers-Rich, Patricia

    2018-01-18

    High-latitude (i.e., "polar") Mesozoic fauna endured months of twilight and relatively low mean annual temperatures. Yet non-avian dinosaurs flourished in this taxing environment. Fossils of basal ornithopod dinosaurs ("hypsilophodontids") are common in the Early Cretaceous high-latitude sediments of Victoria, Australia, and four taxa have been described; although their ontogenetic histories are largely unexplored. In the present study, eighteen tibiae and femora were utilized in the first multi-specimen ontogenetic histological analysis of Australian polar hypsilophodontids. The sample consists of eleven individuals from the Flat Rocks locality (Late Valanginian or Barremian), and five from the Dinosaur Cove locality (Albian). In both groups, growth was most rapid during the first three years, and skeletal maturity occurred between five and seven years. There is a weak asymptotic trend in a plot of growth mark count versus femur length, with considerable individual variation. Histology suggests two genera are present within the Dinosaur Cove sample, but bone microstructure alone could not distinguish genera within the Flat Rocks sample, or across the two geologically separate (~ 26 Ma) localities. Additional histologic sampling, combined with morphological analyses, may facilitate further differentiation between ontogenetic, individual, and species variation.

  15. Sand dune movement in the Victoria Valley, Antarctica

    Bourke, Mary C.; Ewing, Ryan C.; Finnegan, David; McGowan, Hamish A.

    2009-08-01

    We use vertical aerial photographs and LiDAR topographic survey data to estimate dune migration rates in the Victoria Valley dunefield, Antarctica, between 1961 and 2001. Results confirm that the dunes migrated an average of 1.5 m/year. These values are consistent with other estimates of dune migration from cold climate deserts and are significantly lower than estimates from warm deserts. Dune migration rates are retarded by the presence of entrained ice, soil moisture and a reversing wind regime. Dune absorption, merging and limb extension are apparent from the time-series images and account for significant changes in dune form and the field-scale dune pattern. Dune-field pattern analysis shows an overall increase in dune-field organization with an increase in mean dune spacing and a reduction in total crest length and defect density. These data suggest that dunes in other cold desert environments on Earth, Mars or Titan, that may also have inter-bedded frozen laminae, still have the potential to migrate and organize, albeit at lower rates than dunes in warm deserts.

  16. The Victoria and Alfred Waterfront as playground for Capetonians

    Sanette Ferreira

    2014-07-01

    Full Text Available The paper contributes to the exploration and understanding of the social geographies of public space in the Victoria & Alfred Waterfront (V&AW in Cape Town. The aim is to understand Capetonians’ (visitors and employees perceptions of the V&AW as public, leisure, shopping and working spaces. The appropriate literature on waterfront developments in providing public, working and leisure space is reviewed. Two questionnaire surveys (visitors and employees as well as eight unstructured interviews with important role players in the tourism industry of Cape Town were conducted. Findings revealed the most important reasons for Capetonians to visit or use certain spaces in the V&AW, the public open spaces they liked and how they perceived the V&AW as an inclusive space. The research also sought the respondents’ views on how the certain public spaces can be improved; what new activities and retail shops can be introduced; their opinions about the affordability of restaurants and parking; and how the V&AW can improve to cater for the needs of the Waterfront’s employees. Recommendations are made for making the V&AW more functional and accessible to Capetonians.

  17. Wetland vegetation establishment in L-Lake

    Kroeger, S.R.

    1990-07-01

    Wetland vegetation was transplanted from PAR Pond to L-Lake between January and August, 1987. Approximately 100,000 individual plants representing over 40 species were transplanted along the southern shoreline. Three zones of vegetation were created: (1) submersed/floating-leaved, (2) emergent, (3) upper emergent/shrub. During the summers of 1987, 1988, 1989, the Savannah River Ecology Laboratory sampled the vegetation in 54 permanent transects located in planted (N=32) and unplanted areas (N=22). The 1989 vegetation data from L-Lake were compared to 1985 data from PAR Pond

  18. Water Resources Data--California, Water Year 2002, Volume 1, Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Rockwell, G.L.; Pope, G.L.; Agajanian, J.; Caldwell, L.A.

    2003-01-01

    Water-resources data for the 2002 water year for California consist of records of stage, discharge, and water quality of streams, stage and contents in lakes and reservoirs, and water levels and water quality in wells. Volume 1 contains discharge records for 188 gaging stations and 10 crest-stage partial-record stations, stage and contents for 19 lakes and reservoirs, gage-height records for 2 stations, water quality for 39 streamflow-gaging stations and 11 partial-record stations, and precipitation data for 1 station. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  19. Water Resources Data -- California, Water Year 2003, Volume 1, Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    Pope, G.L.; Agajanian, J.; Caldwell, L.A.; Rockwell, G.L.

    2004-01-01

    Water-resources data for the 2003 water year for California consist of records of stage, discharge, and water quality of streams, stage and contents in lakes and reservoirs, and water levels and water quality in wells. Volume 1 contains discharge records for 193 gaging stations and 11 crest-stage partial-record stations, stage and contents for 22 lakes and reservoirs, gage-height records for 2 stations, water quality for 47 streamflow-gaging stations and 12 partial-record stations, and precipitation data for 1 station. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  20. Water resources data, California, water year 2004, volume 1: Southern Great Basin from Mexican border to Mono Lake Basin, and Pacific Slope basins from Tijuana River to Santa Maria River

    Agajanian, J.; Caldwell, L.A.; Rockwell, G.L.; Pope, G.L.

    2005-01-01

    Water-resources data for the 2004 water year for California consist of records of stage, discharge, and water quality of streams, stage and contents in lakes and reservoirs, and water levels and water quality in wells. Volume 1 contains discharge records for 195 gaging stations and 10 crest-stage partial-record stations, stage and contents for 25 lakes and reservoirs, gage-height records for 2 stations, water quality for 47 streamflow-gaging stations and 7 partial-record stations, and precipitation data for 5 stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

  1. Assessing Lake Level Variability and Water Availability in Lake Tana, Ethiopia using a Groundwater Flow Model and GRACE Satellite Data

    Hasan, E.; Dokou, Z.; Kirstetter, P. E.; Tarhule, A.; Anagnostou, E. N.; Bagtzoglou, A. C.; Hong, Y.

    2017-12-01

    Lake Tana is the source of the Blue Nile and Ethiopia's largest natural buffer against seasonal variations of rainfall. Assessing the interactions between the lake level fluctuation, hydroclimatic variabilities and anthropogenic factors is essential to detect drought conditions and identify the role of human management in controlling the Lake water balance. Via an extended record of Total Water Storage (TWS) anomalies for the period 1960-2016, a water budget model for the lake water inflow/outflow was developed. Estimates of Lake Level Altimetry (LLA) based on in-situ and satellite altimetry were composited from 1960-2016 and compared to the extended TWS anomalies, the self-calibrated Palmer Drought Severity Index (scPDSI), the El Niño Southern Oscillation (ENSO) and the historical lake water levels and releases. In addition, the simulated lake levels and water budget from a coupled groundwater and lake model of the Lake Tana basin were compared to the above results. Combining the different approaches, the water budget of the lake can be monitored, the drought conditions can be identified and the role of human management in the lake can be determined. For instance, three major drought periods are identified, 1970 to 1977, 1979 to 1987 and 1990 to 1998, each succeeded with an interposed flooding related recovery year, i.e. 1978, 1988 and 1999. The drought/flooding events were attributed mainly to the ENSO interactions that resulted in lake level fluctuations. The period from 2002-2006 was associated with a remarkable decline of the lake level that was attributed partly in drought conditions and the full flow regulation of the Chara Chara weir at the lake outlet, initiated in 2001.

  2. Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    Xu Weihai; Zhang Gan; Zou Shichun; Li Xiangdong; Liu Yuchun

    2007-01-01

    Nine selected antibiotics in the Victoria Harbour of Hong Kong and the Pearl River at Guangzhou, South China, were analyzed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the concentrations of antibiotics were mainly below the limit of quantification (LOQ) in the marine water of Victoria Harbour. However, except for amoxicillin, all of the antibiotics were detected in the Pearl River during high and low water seasons with the median concentrations ranging from 11 to 67 ng/L, and from 66 to 460 ng/L, respectively; and the concentrations in early spring were about 2-15 times higher than that in summer with clearer diurnal variations. It was suggested that the concentrations of antibiotics in the high water season were more affected by wastewater production cycles due to quick refreshing rate, while those in the low water season may be more sensitive to the water column dynamics controlled by tidal processes in the river. - Antibiotics were found at high concentrations in an urban reach of Pearl River in southern China with contrast diurnal variations between the high and low water seasons

  3. Plutonium and americium in Lake Michigan sediments

    Edgington, D.N.; Alberts, J.J.; Wahlgren, M.A.; Karttunen, J.O.; Reeve, C.A.

    1975-01-01

    The vertical distributions of 239 , 240 Pu, 238 Pu, and 137 Cs have been measured in sediment cores taken from Lake Michigan. Sections from a limited number of cores have been analyzed for 241 Am. In addition, grab samples from ten locations in the southern basin of the lake have been analyzed for phase distribution of 239 , 240 Pu using a sequential extraction technique. The results indicate that the 239 , 240 Pu, 238 Pu, and 137 Cs from weapons testing, and the 241 Am formed in situ are concentrated in the sediments. A comparison of the total deposition of 239 , 240 Pu and 137 Cs indicates that 137 Cs may be valuable as a monitor for 239 , 240 Pu deposition in the sediments. Values of the 238 Pu/ 239 , 240 Pu ratio are in agreement with values reported in Lake Ontario sediments (and Lake Michigan plankton) and show little variation with depth. 241 Am data support the concept of in situ production with little preferential mobility after formation. Studies of sedimentary phase distributions show that 239 , 240 Pu is associated with hydrous oxide phases which are chemically stable under the prevailing conditions in lake sediments. Since Lake Michigan sediments remain aerobic, relatively little 239 , 240 Pu is available for chemical mobilization from the hydrous oxide or organic phases present in the sediments

  4. Limnology of Eifel maar lakes

    Scharf, Burkhard W; Björk, Sven

    1992-01-01

    ... & morphometry - Physical & chemical characteristics - Calcite precipitation & solution in Lake Laacher See - Investigations using sediment traps in Lake Gemundener Maar - Phytoplankton of Lake Weinfelder Maar...

  5. The epidemiology of hip fractures across western Victoria, Australia.

    Holloway, Kara L; Sajjad, Muhammad A; Mohebbi, Mohammadreza; Kotowicz, Mark A; Livingston, Patricia M; Khasraw, Mustafa; Hakkennes, Sharon; Dunning, Trisha L; Brumby, Susan; Page, Richard S; Pedler, Daryl; Sutherland, Alasdair; Venkatesh, Svetha; Brennan-Olsen, Sharon L; Williams, Lana J; Pasco, Julie A

    2018-03-01

    Hip fractures are associated with considerable morbidity and mortality. Hip fracture incidence varies across different levels of accessibility/remoteness and socioeconomic status (SES). As part of the Ageing, Chronic Disease and Injury Study, we aimed to map the pattern of hip fractures across the western region of the Australian state of Victoria, which contains a range of remoteness levels and SES. Data on hip fractures resulting in hospital admission were extracted from the Victorian Admitted Episodes Dataset (VAED) for men and women aged 40+years during 2010-2013 inclusive. An age-adjusted incidence rate (per 10,000population/year) was calculated for the entire region. Crude incidence rates and length of acute care hospital stay (excluding rehabilitation) were calculated for each Local Government Area (LGA). The impact of aggregated age, accessibility/remoteness index of Australia (ARIA) and SES on hip fracture rates aggregated across LGAs was determined using Poisson regression. For men, the age-standardised rate of hospitalisations for hip fracture across the whole region was 19.2 per 10,000population/year (95%CI 18.0-20.4) and for women, 40.0 (95%CI 38.3-41.7). The highest incidence rates for both sexes occurred in the less accessible LGAs of Yarriambiack and Hindmarsh, as well as the LGA with the lowest SES, Central Goldfields. In both sexes, approximately two thirds of individuals were discharged from acute hospital care within 14days. Increasing age, higher remoteness and lower SES were all associated with higher hip fracture rates. Crude incidence rates varied by location. Given that a high proportion of patients had acute hospital care of ≤14days, and accessibility and SES were associated with hip fracture rates, these results can inform policy and provide a model for other groups to conduct similar research in their local environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Impact of cruise ship emissions in Victoria, BC, Canada

    Poplawski, Karla; Setton, Eleanor; McEwen, Bryan; Hrebenyk, Dan; Graham, Mark; Keller, Peter

    2011-02-01

    Characterization of the effects of cruise ship emissions on local air quality is scarce. Our objective was to investigate community level concentrations of fine particulate matter (PM 2.5), nitrogen dioxide (NO 2) and sulphur dioxide (SO 2) associated with cruise ships in James Bay, Victoria, British Columbia (BC), Canada. Data obtained over four years (2005-2008) at the nearest air quality network site located 3.5 km from the study area, a CALPUFF modeling exercise (2007), and continuous measurements taken in the James Bay community over a three-month period during the 2009 cruise ship season were examined. Concentrations of PM 2.5 and nitrogen oxide (NO) were elevated on weekends with ships present with winds from the direction of the terminal to the monitoring station. SO 2 displayed the greatest impact from the presence of cruise ships in the area. Network data showed peaks in hourly SO 2 when ships were in port during all years. The CALPUFF modeling analysis found predicted 24-hour SO 2 levels to exceed World Health Organization (WHO) guidelines of 20 μg m -3 for approximately 3% of 24-hour periods, with a maximum 24-hour concentration in the community of 41 μg m -3; however, the CALPUFF model underestimated concentrations when predicted and measured concentrations were compared at the network site. Continuous monitoring at the location in the community predicted to experience highest SO 2 concentrations measured a maximum 24-hour concentration of 122 μg m -3 and 16% of 24-hour periods were above the WHO standard. The 10-minute concentrations of SO 2 reached up to 599 μg m -3 and exceeded the WHO 10-minute SO 2 guideline (500 μg m -3) for 0.03% of 10-minute periods. No exceedences of BC Provincial or Canadian guidelines or standards were observed.

  7. Variability in methane emissions from West Siberia's shallow boreal lakes on a regional scale and its environmental controls

    A. F. Sabrekov

    2017-08-01

    Full Text Available Small lakes represent an important source of atmospheric CH4 from northern wetlands. However, spatiotemporal variations in flux magnitudes and the lack of knowledge about their main environmental controls contribute large uncertainty into the global CH4 budget. In this study, we measured methane fluxes from small lakes using chambers and bubble traps. Field investigations were carried out in July–August 2014 within the West Siberian middle and southern taiga zones. The average and median of measured methane chamber fluxes were 0.32 and 0.30 mgCH4 m−2 h−1 for middle taiga lakes and 8.6 and 4.1 mgCH4 m−2 h−1 for southern taiga lakes, respectively. Pronounced flux variability was found during measurements on individual lakes, between individual lakes and between zones. To analyze these differences and the influences of environmental controls, we developed a new dynamic process-based model. It shows good performance with emission rates from the southern taiga lakes and poor performance for individual lakes in the middle taiga region. The model shows that, in addition to well-known controls such as temperature, pH and lake depth, there are significant variations in the maximal methane production potential between these climatic zones. In addition, the model shows that variations in gas-filled pore space in lake sediments are capable of controlling the total methane emissions from individual lakes. The CH4 emissions exhibited distinct zonal differences not only in absolute values but also in their probability density functions: the middle taiga lake fluxes were best described by a lognormal distribution while the southern taiga lakes followed a power-law distribution. The latter suggests applicability of self-organized criticality theory for methane emissions from the southern taiga zone, which could help to explain the strong variability within individual lakes.

  8. 78 FR 59625 - Drawbridge Operation Regulation; Lake Pontchartrain, Near Slidell, LA

    2013-09-27

    ... operating schedule that governs the Norfolk Southern Railroad Bridge across Lake Pontchartrain, mile 4.80... clearance of two feet, above Mean Sea Level, in the closed-to- navigation position and an unlimited vertical...

  9. Bathymetry of Lake Erie and Lake Saint Clair

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

  10. Water resources data for California, water year 1979; Volume 1: Colorado River basin, Southern Great Basin from Mexican Border to Mono Lake basin, and Pacific slope basins from Tijuana River to Santa Maria River

    ,

    1981-01-01

    Water-resources data for the 1979 water year for California consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; records of water levels in selected observation wells; and selected chemical analyses of ground water. Records for a few pertinent streamflow and water-quality stations in bordering States are also included. These data, a contribution to the National Water Data System, were collected by the Geological Survey and cooperating local, State, and Federal agencies in California.

  11. Water resources data for California, water year 1978; Volume 1: Colorado River basin, southern Great Basin from Mexican border to Mono Lake basin, and Pacific Slope basins from Tijuana River to Santa Maria River

    ,

    1979-01-01

    Water-resources data for the 1978 water year for California consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; records of water levels in selected observation wells; and selected chemical analyses of ground water. Records for a few pertinent streamflow and water-quality stations in bordering States are also included. These data, a contribution to the National water Data System, were collected by the Geological Survey and cooperating local, State, and Federal agencies in California.

  12. Thermal structure and circulation in Lake Chapala, Mexico

    David Avalos-Cueva

    2016-03-01

    Full Text Available This study analyzed and discussed the instrumental measurements of temperature and currents made on January 10, 2007, in Lake Chapala. We received new data on the formation of the thermocline. It is shown that the thermocline of the lake is formed only in the daytime and in a top-heated 0.5-1.0 m layer. The vertical temperature gradient reaches 2.5°C in the first meter, and the spatial average temperature across the lake showed that the northern end of the lake is, on average, 1°C warmer than the southern end. We numerically modelled the currents in the lake for the dry season using the HAMSOM 2D hydrodynamic model. The simulation results are in good agreement with the acoustic Doppler current profiler ADCP measurements. In the dry season, two gyres were found: a cyclonic gyre in the eastern part and an anticyclonic gyre in the western part.

  13. Analyses of CsI aerosol deposition tests in WIND project with ART and VICTORIA codes

    Yuchi, Y.; Shibazaki, H.; Kudo, T.

    2000-01-01

    Deposition behavior of cesium iodide (CsI) was analyzed with ART and VICTORIA-92 codes for a test of the aerosol re-vaporization test series performed in WIND project at JAERI. In the test analyzed, CsI aerosol was injected into piping of test section where metaboric acid (HBO 2 ) was placed in advance on the floor area. It was confirmed in the present analysis that similar results on the CsI deposition were obtained between ART and VICTORIA when influences of chemical interactions were negligibly small. The analysis with VICTORIA agreed satisfactorily with the test results in analytical cases that cesium metaborate (CsBO 2 ) was injected into the test section instead of CsI to simulate the pre-existence of HBO 2 effect. (author)

  14. Understanding virtual water flows: A multiregion input-output case study of Victoria

    Lenzen, Manfred

    2009-09-01

    This article explains and interprets virtual water flows from the well-established perspective of input-output analysis. Using a case study of the Australian state of Victoria, it demonstrates that input-output analysis can enumerate virtual water flows without systematic and unknown truncation errors, an issue which has been largely absent from the virtual water literature. Whereas a simplified flow analysis from a producer perspective would portray Victoria as a net virtual water importer, enumerating the water embodiments across the full supply chain using input-output analysis shows Victoria as a significant net virtual water exporter. This study has succeeded in informing government policy in Australia, which is an encouraging sign that input-output analysis will be able to contribute much value to other national and international applications.

  15. Urbanization and mental health: psychiatric morbidity, suicide and violence in the State of Victoria.

    Krupinski, J

    1979-06-01

    Australia is one of the most urbanized countries in the world with over 85% of the population living in metropolitan and other urban areas. More important, the change from a predominantly rural society to an urbanized society has occurred within the last 100 years. To assess the effects of urbanization on mental health, rates of admissions to psychiatric institutions, suicides and violent crime in Victoria have been analysed for the last hundred years. Data on admissions to psychiatric facilities in Victoria from metropolitan, other urban and rural areas, as well as results of community health surveys carried out in metropolitan and rural areas were compared to examine for evidence of urban-rural differences in psychiatric morbidity. The findings do not support the notion that the level of psychiatric and psychosocial disorders in Victoria are related to urbanization or to urban living.

  16. VICTORIA: A mechanistic model of radionuclide behavior in the reactor coolant system under severe accident conditions

    Heams, T.J.; Williams, D.A.; Johns, N.A.; Mason, A.; Bixler, N.E.; Grimley, A.J.; Wheatley, C.J.; Dickson, L.W.; Osborn-Lee, I.; Domagala, P.; Zawadzki, S.; Rest, J.; Alexander, C.A.; Lee, R.Y.

    1992-12-01

    The VICTORIA model of radionuclide behavior in the reactor coolant system (RCS) of a light water reactor during a severe accident is described. It has been developed by the USNRC to define the radionuclide phenomena and processes that must be considered in systems-level models used for integrated analyses of severe accident source terms. The VICTORIA code, based upon this model, predicts fission product release from the fuel, chemical reactions involving fission products, vapor and aerosol behavior, and fission product decay heating. Also included is a detailed description of how the model is implemented in VICTORIA, the numerical algorithms used, and the correlations and thermochemical data necessary for determining a solution. A description of the code structure, input and output, and a sample problem are provided

  17. A Record of Holocene Paleoclimate Evolution from Robertson Bay, Victoria Land, Antarctica

    Riesselman, C. R.; Truax, O.; Wilson, G. S.; Parker, R. L.; Yoo, K. C.; Lee, J. I.; Levy, R. H.; Mckay, R. M.

    2017-12-01

    Regionally representative records of how Antarctica responded to the transition from the Last Glacial Maximum into the Holocene are an essential component of understanding the processes by which the Antarctic cryosphere responds to a changing climate. Here, we present a high-resolution record of Holocene Antarctic paleoclimate evolution from a previously unstudied section of the Victoria Land margin. In 2015 the Korea Polar Research Institute collected a 571 cm sediment core, GC57, from Robertson Bay, a protected embayment west of Cape Adare and adjacent to the outlet glaciers of the Transantarctic Mountains. Using diatom assemblages, bulk sediment geochemistry, and the magnetic properties of GC57, we aim to reconstruct the response of the East Antarctic Ice Sheet to warming associated with deglaciation and the Holocene climatic optima at the interface between the Ross Sea and the Southern Ocean. Our multiproxy approach allows us to study sea ice extent, seasonality, ocean stratification and circulation, and primary productivity from the mid-Holocene (7,400 14C year BP) to the present. A sea-ice associated diatom assemblage indicative of summer sea surface temperatures below 0˚C dominates the basal section of GC57. Although diatoms are well preserved, the unit is characterized by low wt% biogenic silica (average 9%) and a high concentration of magnetic minerals, indicating that biogenic production persisted despite substantial terrigenous input into the bay. A rapid transition at 4708 14C yr BP is identified by a steep increase in wt% BSi (average 13%), a decrease in magnetic minerals, and a subtle assemblage change towards sea-ice associated diatoms with slightly warmer temperature tolerances. The novel ramped pyrolosis 14C dating methodology allows us to date the carbon fixed concurrent with deposition and generate a robust age model for GC57 with an accuracy previously difficult to achieve given the uncertainties associated with dating bulk acid insoluble

  18. Stroke Incidence in Victoria, Australia—Emerging Improvements

    Benjamin B. Clissold

    2017-05-01

    Full Text Available BackgroundEvidence of a decline in the incidence of stroke has emerged from population-based studies. These have included retrospective and prospective cohorts. However, in Australia and other countries, government bodies and stroke foundations predict a rise in the prevalence of stroke that is anticipated to increase the burden of stroke across the entire domain of care. This increase in prevalence must be viewed as different from the decline in incidence being observed, a measure of new stroke cases. In Victoria, all public emergency department visits and public and private hospital admissions are reported to the Department of Health and Human Services and include demographic, diagnostic, and procedural/treatment information.MethodsWe obtained data from financial years 1997/1998 to 2007/2008 inclusive, for all cases with a primary stroke diagnosis (ICD-10-AM categories with associated data fields. Incident cases were established by using a 5-year clearance period.ResultsFrom 2003/2004 to 2007/2008 inclusive, there were 53,425 patients with a primary stroke or TIA diagnosis. The crude incident stroke rate for first ever stroke was 211 per 100,000 per year (95% CI 205–217 [females—205 per 100,000 per year (95% CI 196–214 and males—217 per 100,000 per year (95% CI 210–224]. The overall stroke rates were seen to significantly decline over the period [males (per 100,000 per year 227 in 2003/2004 to 202 in 2007/2008 (p = 0.0157 and females (per 100,000 per year 214 in 2003/2004 to 188 in 2007/2008 (p = 0.0482]. Ischemic stroke rates also appeared to decline; however, this change was not significant.ConclusionThese results demonstrate a significant decline in stroke incidence during the study period and may suggest evidence for effectiveness of primary and secondary prevention strategies in cerebrovascular risk factor management.

  19. La Victoria de Pedro Aguirre Cerda: ideas para una renovación urbana sin gentrificación para Santiago./ La Victoria of Pedro Aguirre Cerda: ideas for an urban renewal without gentrification in Santiago.

    Ernesto López

    2012-12-01

    Full Text Available El modelo de renovación urbana en altura de Santiago, en expansión hacia áreas populares del pericentro, es una forma de acumulación de renta de suelo, con efectos de desplazamiento social, es decir, gentrificación. Sin embargo, el pericentro de Santiago es un espacio donde coexisten amplias necesidades y capacidades de densificación urbana sin desplazamiento. Tomando como caso de estudio el desarrollo urbano histórico y actual de la población La Victoria, en Pedro Aguirre Cerda (PAC, se plantea una investigación enfocada en dos perspectivas: histórica, definiendo este espacio desde la dialéctica entre movimientos sociales urbanos y producción espacial específica; y normativa, como una propuesta espacial que combina aspectos claves de mejoramiento barrial y densificación inclusiva y autosustentable. Se evidencia de esta forma la alta complejidad espacial del pericentro de Santiago de Chile, así como la existencia de alternativas de renovación residencial pericentral que sean social y políticamente inclusivas y de bajo impacto en términos de expulsión./ The model of high-rise urban renewal sprawls towards Santiago de Chile’s inner city. This model can be understood as a form of gentrification based on considerable accumulation of the rent gap, while its externalities generate social displacement and physical dilapidation. Notwithstanding, Santiago’s inner city is also a lived space where both needs and capacities of urban regeneration (without displacement coexist. Focusing on the case of La Victoria población, located in the southern municipality of Pedro Aguirre Cerda (PAC, this article seeks to address the following two topics: historically, the inner city responds to a dialectic of urban social movements and specific spatial production; normatively, as an ongoing research project shows, it is feasible to combine neighbourhood regeneration, urban density increase, and citizen participation. The article substantiates the

  20. Deglaciation, lake levels, and meltwater discharge in the Lake Michigan basin

    Colman, Steven M.; Clark, J.A.; Clayton, L.; Hansel, A.K.; Larsen, C.E.

    1994-01-01

    The deglacial history of the Lake Michigan basin, including discharge and routing of meltwater, is complex because of the interaction among (1) glacial retreats and re-advances in the basin (2) the timing of occupation and the isostatic adjustment of lake outlets and (3) the depositional and erosional processes that left evidence of past lake levels. In the southern part of the basin, a restricted area little affected by differential isostasy, new studies of onshore and offshore areas allow refinement of a lake-level history that has evolved over 100 years. Important new data include the recognition of two periods of influx of meltwater from Lake Agassiz into the basin and details of the highstands gleaned from sedimentological evidence. Major disagreements still persist concerning the exact timing and lake-level changes associated with the Algonquin phase, approximately 11,000 BP. A wide variety of independent data suggests that the Lake Michigan Lobe was thin, unstable, and subject to rapid advances and retreats. Consequently, lake-level changes were commonly abrupt and stable shorelines were short-lived. The long-held beliefs that the southern part of the basin was stable and separated from deformed northern areas by a hinge-line discontinuity are becoming difficult to maintain. Numerical modeling of the ice-earth system and empirical modeling of shoreline deformation are both consistent with observed shoreline tilting in the north and with the amount and pattern of modern deformation shown by lake-level gauges. New studies of subaerial lacustrine features suggest the presence of deformed shorelines higher than those originally ascribed to the supposed horizontal Glenwood level. Finally, the Lake Michigan region as a whole appears to behave in a similar manner to other areas, both local (other Great Lakes) and regional (U.S. east coast), that have experienced major isostatic changes. Detailed sedimentological and dating studies of field sites and additional

  1. Australian doctors and the visual arts. Part 4. Doctors as supporters of art galleries and artists in Victoria.

    Hamilton, D G

    1986-07-07

    The contribution of doctors to the visual arts is being discussed in a series of six articles. Doctor-artists in New South Wales and Victoria, and doctors as collectors, donors, gallery supporters and writers in New South Wales, have been discussed in earlier articles. This, the fourth article, deals with doctors as supporters of art galleries and artists in Victoria.

  2. Effects of complex effluents on photosynthesis in Lake Erie and Lake Huron

    Bridgham, S.D.; McNaught, D.C.; Meadows, C.

    1988-01-01

    Phytoplankton are the base of the food chain in most large lake ecosystems; if affected by environmental pollutants, significant ecosystem changes can result with potential impact on higher trophic levels. The research determined the effects of a complex effluent discharge from the River Raisin in Monroe County, Michigan, on the Lake Erie ecosystem. The river flows through southern Michigan and has large nutrient and industrial inputs, especially in the Monroe Harbor area. The functional parameters measured were bacterial uptake rate of acetate, zooplankton feeding and reproduction rates, and primary production. The results of the effects of complex effluents on gross photosynthesis, measured as carbon-14 ((14)C) uptake, are presented in the paper

  3. Stratigraphic architecture of bedrock reference section, Victoria Crater, Meridiani Planum, Mars

    Edgar, Lauren A.; Grotzinger, John P.; Hayes, Alex G.; Rubin, David M.; Squyres, Steve W.; Bell, James F.; Herkenhoff, Ken E.

    2012-01-01

    The Mars Exploration Rover Opportunity has investigated bedrock outcrops exposed in several craters at Meridiani Planum, Mars, in an effort to better understand the role of surface processes in its geologic history. Opportunity has recently completed its observations of Victoria crater, which is 750 m in diameter and exposes cliffs up to ~15 m high. The plains surrounding Victoria crater are ~10 m higher in elevation than those surrounding the previously explored Endurance crater, indicating that the Victoria crater exposes a stratigraphically higher section than does the Endurance crater; however, Victoria strata overlap in elevation with the rocks exposed at the Erebus crater. Victoria crater has a well-developed geomorphic pattern of promontories and embayments that define the crater wall and that reveal thick bedsets (3–7m) of large-scale cross-bedding, interpreted as fossil eolian dunes. Opportunity was able to drive into the crater at Duck Bay, located on the western margin of Victoria crater. Data from the Microscopic Imager and Panoramic Camera reveal details about the structures, textures, and depositional and diagenetic events that influenced the Victoria bedrock. A lithostratigraphic subdivision of bedrock units was enabled by the presence of a light-toned band that lines much of the upper rim of the crater. In ascending order, three stratigraphic units are named Lyell, Smith, and Steno; Smith is the light-toned band. In the Reference Section exposed along the ingress path at Duck Bay, Smith is interpreted to represent a zone of diagenetic recrystallization; however, its upper contact also coincides with a primary erosional surface. Elsewhere in the crater the diagenetic band crosscuts the physical stratigraphy. Correlation with strata present at nearby promontory Cape Verde indicates that there is an erosional surface at the base of the cliff face that corresponds to the erosional contact below Steno. The erosional contact at the base of Cape Verde

  4. A Systematic Study of Zerbar Lake Restoration

    Hosseini, Reza; Oveis Torabi, Seyed; Forman Asgharzadeh, Deonna

    2017-04-01

    The beautiful lake of Zerbar, located near Marivan City at the west of Iran, is a freshwater lake with an area of 20 km2 and average depth of 5 meters. The lake is created by regional tectonic activities and is mainly fed with natural spring water from bottom. During the past three decades, regional development has caused much disturbance to the natural environment of the lake and its watershed. Rescuing the lake is crucial to the sustainability of the whole region. The study of Zerbar Restoration was performed with the aim to restore its health indicators. Variety of human activities in the watershed, as well as the multidisciplinary nature of lake restoration studies, made it necessary to develop a systematic approach to conduct the study. In Step I of restoration studies, satellite images were investigated to identify the historical changes of watershed during the past 30 years. Meanwhile, documents since 50 years ago were studied. Results indicate that farmland and graze land areas have been relatively constant during the past 50 years. Also, the area of lake, its riparian canes and floating plants have not changed much. In fact, the only significant land use change observed was the significant spread of Marivan City that has stretched toward the lake. The main physical variation to the lake has been elevating the southern edge of the lake by a constructing a landfill dam which was done to control the lake's overflow discharge for irrigation of downstream farmland development. Step II consists of studies performed by disciplines of water resources, hydrogeology, water quality, wetland and watershed ecology, agriculture, animal farming and fishery. Study results indicate that eutrophication (TSL>100), mainly caused by sewage from Marivan City and the surrounding rural areas has been the main reason for lake ecosystem degradation. DPSIR framework, as a novel approach in lake restoration, was applied to synthesize the study results of different disciplines in a

  5. Lake or Pond WBID

    Vermont Center for Geographic Information — The VT DEC (Vermont Department of Environmental Conservation) manages an inventory of lake and pond information. The "Lakes and Ponds Inventory" stores the Water...

  6. National Lakes Assessment Data

    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....

  7. DNR 24K Lakes

    Minnesota Department of Natural Resources — Medium scale lake polygons derived from the National Wetlands Inventory (NWI) polygons and MnDOT Basemap lake delineations. Integrated with the DNR 24K Streams...

  8. Water resources data for California, water year 1976; Volume 1: Colorado River basin, southern Great Basin from Mexican border to Mono Lake basin, and Pacific Slope basins from Tijuana River to Santa Maria River

    ,

    1977-01-01

    Water-resources data for the 1976 water year for California consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; records of water levels in selected observation wells; and selected chemical analyses of ground water. Records for a few pertinent streamflow and water-quality stations in bordering States are also included. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of Lee R. Peterson, district chief; Winchell Smith, assistant district chief for hydrologic data; and Leonard N. Jorgensen, chief of the basic-data section. These data, a contribution to the National Water Data System, were collected by the Geological Survey and cooperating local, State, and Federal agencies in California.

  9. Water resources data for California, water year 1977; Volume 1: Colorado River Basin, Southern Great Basin from Mexican Border to Mono Lake Basin, and Pacific Slope Basins from Tijuana River to Santa Maria River

    ,

    1978-01-01

    Water-resources data for the 1977 water year for California consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; records of water levels in selected observation wells; and selected chemical analyses of ground water. Records for a few pertinent streamflow and water-quality stations in bordering States are also included. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of Winchell Smith, Assistant District Chief for Hydrologic Data and Leonard N. Jorgensen, Chief of the Basic-Data Section. These data, a contribution to the National Water Data System, were collected by the Geological Survey and cooperating local, State, and Federal agencies in California.

  10. Employment Shifts in the Technical and Further Education Workforce in Victoria.

    Shah, Chandra

    2003-01-01

    Analyzes changes in Technical and Further Education (TAFE) work force in Victoria, Australia, that occurred during the period 1993-98. Main changes include increased participation of women, significant growth in part-time employment, decline in full-time (mainly male) employment, and an increased use of seasonal teachers. (Includes 10 figures and…

  11. Perception of Aquaculture Education to Support Further Growth of Aquaculture Industry in Victoria, Australia

    Awal, Sadiqul; Christie, Andrew; Watson, Matthew; Hannadige, Asanka G. T.

    2012-01-01

    Purpose: The central aim of this study was to determine the perception of aquaculture educational provisions in the state of Victoria, and whether they are sufficient to ultimately support further growth of the industry. Design/methodology/approach: Questionnaires were formulated and distributed to participants in a variety of ways, including via…

  12. Australian doctors and the visual arts. Part 3. Doctor-artists in Victoria.

    Hamilton, D G

    1986-06-09

    The contribution of doctors to the visual arts is being discussed in a series of six articles. The first two articles dealt with doctors and the visual arts in New South Wales. In this, the third, doctor-artists in Victoria are discussed.

  13. Communicating Risk with Parents: Exploring the Methods and Beliefs of Outdoor Education Coordinators in Victoria, Australia

    Dallat, Clare

    2009-01-01

    This paper examines the risk communication strategies currently being employed by seven outdoor education co-ordinators in Government schools in Victoria, Australia. Of particular interest are the beliefs and assumptions held by these co-ordinators in relation to communicating risk with parents. Current policy stipulates that parents must be…

  14. medical recipients of the victoria cross during the anglo-boer war

    ofall orders ofchivalry - the most enviable order ofthe. Victoria Cross.' MEDICAL .... Major Babtie, a Scot by birth, obtained his Bachelor of Medicine in 1880 and entered the Army ..... a personality type that is given to this kind of action? Will one.

  15. Supervision and Satisfaction among School Psychologists: An Empirical Study of Professionals in Victoria, Australia

    Thielking, Monica; Moore, Susan; Jimerson, Shane R.

    2006-01-01

    This study examined the supervision arrangements and job satisfaction among school psychologists in Victoria, Australia. Participation in professional supervision was explored in relation to the type of employment and job satisfaction. The results revealed that the frequency of participation in supervision activities was less than optimal, with…

  16. "Embodied Knowing": Exploring the Founding of the Melbourne Rudolf Steiner School in 1970S Victoria, Australia

    Bak, Tao

    2018-01-01

    Education in Victoria, Australia not only underwent significant change in the 1970s, but was witness to a widespread educational reform project. Whilst exploration of the more widespread alternatives has been of some interest, the smaller progressive traditions that emerged in some ways "alongside" the broader reforms have rarely been…

  17. The Killing of the Workers' Educational Association of Victoria: A Myth Challenged

    Dadswell, Gordon

    2004-01-01

    On 21 March 1941, the Council of the Workers' Educational Association of Victoria, Australia, (the Association) voted the organisation out of existence. The demise was in no way contemplated, and there was no practical reason why the Council acted in the way it did. This paper is the story of the destruction of a successful adult education…

  18. Chlamydia pecorum Infection in Free-ranging Koalas ( Phascolarctos cinereus ) on French Island, Victoria, Australia.

    Legione, Alistair R; Amery-Gale, Jemima; Lynch, Michael; Haynes, Leesa; Gilkerson, James R; Sansom, Fiona M; Devlin, Joanne M

    2016-04-28

    We detected Chlamydia pecorum in two koalas ( Phascolarctos cinereus ) from a closed island population in Victoria, Australia, previously free of Chlamydia infection. The ompA and multilocus sequence type were most closely related to published isolates of livestock rather than koala origin, suggesting potential cross-species transmission of C. pecorum .

  19. Focus on Form and Corrective Feedback Research at the University of Victoria, Canada

    Chen, Sibo; Nassaji, Hossein

    2018-01-01

    The Department of Linguistics at University of Victoria (UVic) in Canada has a long-standing tradition of empirical approaches to the study of theoretical and applied linguistics. As part of the Faculty of Humanities, the department caters to students with a wide range of backgrounds and interests, and provides crucial language teaching support in…

  20. Levels and patterns of persistent organic pollutants (POPs) in tilapia (Oreochromis sp.) from four different lakes in Tanzania: geographical differences and implications for human health.

    Polder, A; Müller, M B; Lyche, J L; Mdegela, R H; Nonga, H E; Mabiki, F P; Mbise, T J; Skaare, J U; Sandvik, M; Skjerve, E; Lie, E

    2014-08-01

    In Tanzania fish is one of the most important protein sources for the rapidly increasing population. Wild fish is threatened by overfishing and pollution from agriculture, industries, mining, household effluents and vector control. To monitor possible implications for public health, the geographical differences of the occurrence and levels of persistent organic pollutants (POPs) in tilapia fish (Oreochromis sp.) from four different Tanzanian lakes were investigated in 2011. Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyls (PBDEs) and hexabromocyclododecane (HBCDD) were determined in pooled samples of tilapia muscle from Lake (L) Victoria, L. Tanganyika, L. Nyasa (also called L. Malawi) and L. Babati in Tanzania in 2011. Levels of Σ-DDTs (274 ng/g lipid weight (lw)) and sum of 7 indicator PCBs (Σ-7PCBs) (17 ng/g lw) were significantly higher in tilapia from L. Tanganyika compared to the other lakes. The highest levels of Σ-endosulfan (94 ng/g lw) were detected in tilapia from L. Victoria. Toxaphenes were detected in low levels in fish from L. Tanganyika and L. Babati. Results revealed a geographic difference in the use of DDT and endosulfan between L. Victoria and L. Tanganyika. Low ratios of DDE/DDT in tilapia from L. Tanganyika indicated an on-going use of DDT in the area. Median levels of ΣBDEs, including BDE-209, were highest in L. Victoria (19.4 ng/g lw) and BDE-209 was present in 68% of the samples from this lake. The presence of BDE-209 indicates increasing influence of imported products from heavy industrialized countries. The measured POP levels in the studied tilapia were all below MRLs of EU or were lower than recommended levels, and thus the fish is considered as safe for human consumption. They may, however, pose a risk to the fish species and threaten biodiversity. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Suspended-sediment budget, flow distribution, and lake circulation for the Fox Chain of Lakes in Lake and McHenry Counties, Illinois, 1997-99

    Schrader, David L.; Holmes, Robert R.

    2000-01-01

    The Fox Chain of Lakes is a glacial lake system in McHenry and Lake Counties in northern Illinois and southern Wisconsin. Sedimentation and nutrient overloading have occurred in the lake system since the first dam was built (1907) in McHenry to raise water levels in the lake system. Using data collected from December 1, 1997, to June 1, 1999, suspended-sediment budgets were constructed for the most upstream lake in the system, Grass Lake, and for the lakes downstream from Grass Lake. A total of 64,900 tons of suspended sediment entered Grass Lake during the study, whereas a total of 70,600 tons of suspended sediment exited the lake, indicating a net scour of 5,700 tons of sediment. A total of 44,100 tons of suspended sediment was measured exiting the Fox Chain of Lakes at Johnsburg, whereas 85,600 tons entered the system downstream from Grass Lake. These suspended-sediment loads indicate a net deposition of 41,500 tons downstream from Grass Lake, which represents a trapping efficiency of 48.5 percent. A large amount of recreational boating takes place on the Fox Chain of Lakes during summer months, and suspended-sediment load was observed to rise from 110 tons per day to 339 tons per day during the 1999 Memorial Day weekend (May 26 ?31, 1999). Presumably, this rise was the result of the boating traffic because no other hydrologic event is known to have occurred that might have caused the rise. This study covers a relatively short period and may not represent the long-term processes of the Fox Chain of Lakes system, although the sediment transport was probably higher than an average year. The bed sediments found on the bottom of the lakes are composed of mainly fine particles in the silt-clay range. The Grass Lake sediments were characterized as black peat with an organic content of between 9 and 18 percent, and the median particle size ranged from 0.000811 to 0.0013976 inches. Other bed material samples were collected at streamflow-gaging stations on the

  2. Seasonal rainfall predictability over the Lake Kariba catchment area

    Muchuru, S

    2014-07-01

    Full Text Available The Lake Kariba catchment area in southern Africa has one of the most variable climates of any major river basin, with an extreme range of conditions across the catchment and through time. Marked seasonal and interannual fluctuations in rainfall...

  3. Diatom distribution in the surficial sediments of Lake Fuxian, Yunnan ...

    ajl yemi

    2011-11-30

    Nov 30, 2011 ... (18.2%); there were some phosphorus post-mines which led to higher total phosphorus concentration than that in southern part. The most outstanding characteristic of diatom ... (212 km2 in surface area) is located in the central Yunnan. Province; it is a oligotrophic freshwater lake. It is the second deepest ...

  4. Glacial lakes in the Horgos river basin and their outbreak risk assessment

    A. P. Medeu

    2013-01-01

    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.

  5. Recovery of acidified mountain lakes in Norway as predicted by the MAGIC model

    Bernard J. COSBY

    2004-02-01

    Full Text Available As part of the EU project EMERGE the biogeochemical model MAGIC was used to reconstruct acidification history and predict future recovery for mountain lakes in two regions of Norway. Central Norway (19 lakes receives low levels of acid deposition, most of the lakes have undergone only minor amounts of acidification, and all are predicted to recover in the future. Central Norway thus represents a reference area for more polluted regions in southern Norway and elsewhere in Europe. Southern Norway (23 lakes, on the other hand, receives higher levels of acid deposition, nearly all the studied lakes were acidified and had lost fish populations, and although some recovery has occurred during the period 1980-2000 and additional recovery is predicted for the next decades, the model simulations indicated that the majority of the lakes will not achieve water quality sufficient to support trout populations. Uncertainties in these predictions include possible future N saturation and the exacerbating effects of climate change. The mountain lakes of southern Norway are among the most sensitive in Europe. For southern Norway additional measures such as stricter controls of emissions of air pollutants will be required to obtain satisfactory water quality in the future.

  6. The table grape 'Victoria' with a long shaped berry: a potential mutation with attractive characteristics for consumers.

    Ferrara, Giuseppe; Gallotta, Alessandra; Pacucci, Carmela; Matarrese, Angela Maria Stella; Mazzeo, Andrea; Giancaspro, Angelica; Gadaleta, Agata; Piazzolla, Francesca; Colelli, Giancarlo

    2017-12-01

    Puglia is the most important region in Italy for table grape production. Since consumers look for new products, the number of table grape varieties has greatly increased in recent years. In a survey in the Puglia region, we identified several years ago a potential mutation of the cv. Victoria. We described this accession in comparison with the standard Victoria for some amphelographic traits. All the characteristics were very similar to the standard Victoria except for the berry shape, which was significantly more elongated. Moreover, the berry of the mutated Victoria showed higher firmness, lightness and chroma than the standard one, with a more intense yellow colour of the skin (appreciated by consumers). The molecular characterisation with 25 SSR markers showed that normal and mutant Victoria were genetically identical at all the analysed loci, thus suggesting that the two accessions could be considered as clones with the difference in berry shape probably due to a somatic mutation. This mutation of the cv. Victoria may have interesting perspective for the market since consumers are always attracted by different shape and colour of the fruits (consumers buy with eyes). This accession can be an alternative clone of the already known standard Victoria. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Uranium distribution in relation to sedimentary facies, Kern Lake, California

    Merifield, P.M.; Carlisle, D.; Idiz, E.; Anderhalt, R.; Reed, W.E.; Lamar, D.L.

    1980-04-01

    Kern Lake has served as a sink for drainage from the southern Sierra Nevada and, in lesser amounts, from the southern Temblor Range. Both areas contain significant uranium source rocks. The uranium content in Holocene Kern Lake sediments correlates best with the mud (silt and clay) fraction. It correlates less well with organic carbon. Biotite grains could account for much of the uranium in the sand fraction, and perhaps the silt fraction as well. The data suggest that fixation of uranium by adsorption on mineral grains is a dominant process in this lake system. Further work is required to determine the importance of cation-exchange of uranium on clays and micas and of organically complexed uranium adsorbed to mineral surfaces. These findings also raise the question of whether uranium transport down the Kern River occurs largely as uranium adsorbed to mineral surfaces

  8. Western Alaska ESI: LAKES (Lake Polygons)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing lakes and land masses used in the creation of the Environmental Sensitivity Index (ESI) for Western Alaska. The...

  9. Pollution at Lake Mariut

    Nour ElDin, H.; Halim, S. N.; Shalby, E.

    2004-01-01

    Lake Mariut, south Alexandria, Egypt suffered in the recent decades from intensive pollution as a result of a continuous discharge of huge amounts of agriculture wastewater that contains a large concentration of the washed pesticides and fertilizers in addition to domestic and industrial untreated wastewater. The over flow from the lake is discharged directly to the sea through El-Max pumping station via EI-Umum drain. Lake Mariout is surrounded by a huge number of different industrial activities and also the desert road is cutting the lake, this means that a huge number of various pollutants cycle through the air and settle down in the lake, by the time and during different seasons these pollutants after accumulation and different chemical interactions will release again from the lake to the surrounding area affecting the surrounding zone

  10. HIV infection in fishing communities of Lake Victoria Basin of Uganda--a cross-sectional sero-behavioral survey.

    Alex Opio

    Full Text Available BACKGROUND: Uganda's first AIDS case was reported in a fishing village. Thereafter, due to varying risk factors, the epidemic spread heterogeneously to all regions, with some populations more affected. Given the recent rising trends in HIV infection in Uganda, it is crucial to know the risk factors in different populations. The aim of this study was to determine the prevalence and risk factors of HIV infection among fishing communities. METHODOLOGY: A cross-sectional survey of 46 fishing communities was conducted in 2010. Following written consent, 911 randomly selected respondents age 15-59 years were interviewed and gave blood for HIV testing. HIV testing was conducted in the field and central laboratory according to national algorithm. Survey protocol was approved by the Science and Ethics Committee of Uganda Virus Research Institute, and cleared by Uganda National Council for Science and Technology. Data was captured by EPIINFO and statistical analysis done in SPSS. FINDINGS: Overall HIV prevalence was 22%; there was no difference by sex (x (2 test, p>0.05. Association with HIV infection was determined by x (2 test, p<0.5. Never married respondents had lower HIV prevalence (6.2% than the ever married (24.1%. HIV prevalence was lower in younger respondents, age 15-24 years (10.8% than in age group 25 years and above (26.1%. Muslims had lower HIV prevalence (14.4% than Christians (25.2%. HIV prevalence was higher among respondents reporting 3 or more lifetime sexual partners (25.3% than in those reporting less numbers (10.8%. HIV prevalence was higher among uncircumcised men (27% than in circumcised men (11%. Multivariate analysis identified 4 risk factors for HIV infection; age, religion, ever condom use and number of lifetime sexual partners. CONCLUSIONS: HIV prevalence in the surveyed communities was three times higher than of general population. This underscores the need for tailor made HIV combination prevention interventions targeting fishing communities.

  11. Schistosoma mansoni infection along the coast of Lake Victoria in Mwanza region, Tanzania

    Olsen, Annette; Kinung'hi, Safari; Magnussen, Pascal

    2015-01-01

    Prevalence and intensity of Schistosoma mansoni infection according to age, sex, and occupation were investigated in 100 first-year students (aged 7-8 years), 100 schoolchildren (aged 9-12 years), and 50 adults (aged 20-55 years) from 149 villages. The schoolchildren provided three stool specimen...

  12. The sero-epidemiology of Rift Valley fever in people in the Lake Victoria Basin of western Kenya.

    Elizabeth Anne Jessie Cook

    2017-07-01

    Full Text Available Rift Valley fever virus (RVFV is a zoonotic arbovirus affecting livestock and people. This study was conducted in western Kenya where RVFV outbreaks have not previously been reported. The aims were to document the seroprevalence and risk factors for RVFV antibodies in a community-based sample from western Kenya and compare this with slaughterhouse workers in the same region who are considered a high-risk group for RVFV exposure. The study was conducted in western Kenya between July 2010 and November 2012. Individuals were recruited from randomly selected homesteads and a census of slaughterhouses. Structured questionnaire tools were used to collect information on demographic data, health, and risk factors for zoonotic disease exposure. Indirect ELISA on serum samples determined seropositivity to RVFV. Risk factor analysis for RVFV seropositivity was conducted using multi-level logistic regression. A total of 1861 individuals were sampled in 384 homesteads. The seroprevalence of RVFV in the community was 0.8% (95% CI 0.5-1.3. The variables significantly associated with RVFV seropositivity in the community were increasing age (OR 1.2; 95% CI 1.1-1.4, p<0.001, and slaughtering cattle at the homestead (OR 3.3; 95% CI 1.0-10.5, p = 0.047. A total of 553 slaughterhouse workers were sampled in 84 ruminant slaughterhouses. The seroprevalence of RVFV in slaughterhouse workers was 2.5% (95% CI 1.5-4.2. Being the slaughterman, the person who cuts the animal's throat (OR 3.5; 95% CI 1.0-12.1, p = 0.047, was significantly associated with RVFV seropositivity. This study investigated and compared the epidemiology of RVFV between community members and slaughterhouse workers in western Kenya. The data demonstrate that slaughtering animals is a risk factor for RVFV seropositivity and that slaughterhouse workers are a high-risk group for RVFV seropositivity in this environment. These risk factors have been previously reported in other studies providing further evidence for RVFV circulation in western Kenya.

  13. The sero-epidemiology of Rift Valley fever in people in the Lake Victoria Basin of western Kenya.

    Cook, Elizabeth Anne Jessie; Grossi-Soyster, Elysse Noel; de Glanville, William Anson; Thomas, Lian Francesca; Kariuki, Samuel; Bronsvoort, Barend Mark de Clare; Wamae, Claire Njeri; LaBeaud, Angelle Desiree; Fèvre, Eric Maurice

    2017-07-01

    Rift Valley fever virus (RVFV) is a zoonotic arbovirus affecting livestock and people. This study was conducted in western Kenya where RVFV outbreaks have not previously been reported. The aims were to document the seroprevalence and risk factors for RVFV antibodies in a community-based sample from western Kenya and compare this with slaughterhouse workers in the same region who are considered a high-risk group for RVFV exposure. The study was conducted in western Kenya between July 2010 and November 2012. Individuals were recruited from randomly selected homesteads and a census of slaughterhouses. Structured questionnaire tools were used to collect information on demographic data, health, and risk factors for zoonotic disease exposure. Indirect ELISA on serum samples determined seropositivity to RVFV. Risk factor analysis for RVFV seropositivity was conducted using multi-level logistic regression. A total of 1861 individuals were sampled in 384 homesteads. The seroprevalence of RVFV in the community was 0.8% (95% CI 0.5-1.3). The variables significantly associated with RVFV seropositivity in the community were increasing age (OR 1.2; 95% CI 1.1-1.4, p<0.001), and slaughtering cattle at the homestead (OR 3.3; 95% CI 1.0-10.5, p = 0.047). A total of 553 slaughterhouse workers were sampled in 84 ruminant slaughterhouses. The seroprevalence of RVFV in slaughterhouse workers was 2.5% (95% CI 1.5-4.2). Being the slaughterman, the person who cuts the animal's throat (OR 3.5; 95% CI 1.0-12.1, p = 0.047), was significantly associated with RVFV seropositivity. This study investigated and compared the epidemiology of RVFV between community members and slaughterhouse workers in western Kenya. The data demonstrate that slaughtering animals is a risk factor for RVFV seropositivity and that slaughterhouse workers are a high-risk group for RVFV seropositivity in this environment. These risk factors have been previously reported in other studies providing further evidence for RVFV circulation in western Kenya.

  14. Improving Income Positions of Primary Producers in International Marketing Channels: The Lake Victoria-EU Nile Perch Case

    Kambewa, E.; Ingenbleek, P.T.M.; Tilburg, van A.

    2008-01-01

    Although fair distribution of incomes within marketing channels and systems receives increasing attention in companies¿ corporate social responsibility policies, the marketing literature offers few insights that may be helpful to initiate projects that improve incomes of primary producers in

  15. Modern process study on Chen Co and Ranwu Lake of Tibetan Plateau

    Ju, J.

    2013-12-01

    Lakes are important junctions of geospheres. There are many lakes distributed on the Tibetan Plateau (TP). Lake sediment is one of the important media for retrieving the past environmental changes. Because of the uniqueness of environment of the TP, sediment, water and ecological system in lakes has local characteristic inevitably. Modern process research on different lakes will benefit interpreting the proxies more accurately. The development of observation station makes the observation and sampling more convenient. Modern process of lakes can be fulfilled in two ways, spatial or seasonal variation study, with a same aim finding out the dominant factors controlling the variations. Chen Co is a closed lake locating at inland area of southern Tibet. Ranwu Lake is an open lake locating at outflow area of SE Tibet. In this study, I studied the spatial and (or) seasonal variation of lake water and sediment in the two distinct types of lakes to make clear the mechanism of modern process. Particular attention was given to the pattern and degree of influence of rivers supplied by glaciers on lakes. Preliminary conclusions are outlined as follow: (1) In the lakes with glacier melt supplying rivers, the patterns of supply of the rivers to the lake are different. In close lake Chen Co, the influence of glacier melt is mainly reflected in the south lake area. In the open lake Ranwu Lake, the influence is comprehensive and direct. This difference influencing patterns how the lake sediments reflected the glacier melt under the past environmental changes. (2) The supply of Kaluxiong Qu River, supplied mainly by glacier melt, to Chen co has North-South difference: more directly to south lake area, reflecting by lower value of conductivity and pH, finer grain size and west to east transporting trend, greater deposition rate, more allogenic fine sediments, not obvious biological and endogenic deposition there. This enlightens the site selection for lake cores and interpretation of

  16. Glacial lakes of the Central and Patagonian Andes

    Wilson, Ryan; Glasser, Neil F.; Reynolds, John M.; Harrison, Stephan; Anacona, Pablo Iribarren; Schaefer, Marius; Shannon, Sarah

    2018-03-01

    The prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3 during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

  17. Erratum to ``Eruption style and petrology of a new carbonatitic suite from the Mt. Vulture (Southern Italy): The Monticchio Lakes Formation'' [Journal of Volcanology and Geothermal Research 78 (1997) 251 265

    Stoppa, Francesco; Principe, Claudia

    1998-01-01

    The Monticchio Lakes Formation (MLF) is a newly identified carbonatite-melilitite tuff sequence which is exposed in the southwestern sector of the Vulture volcano. It is the youngest example (ca. 0.13 m.y.) of this type of volcanism in Italy, although other carbonatites of smaller volume, but with similar characteristics, have been discovered recently. This volcanic event occurred in isolation after a 0.35 m.y. period of inactivity at Vulture. The eruption produced two maar-type vents and formed tuff aprons mainly composed of dune beds of lapilli. Depositional features suggest that a dry surge mechanism, possibly triggered by CO 2 expansion, was dominant during tuff emplacement. The MLF event involved a mixture of carbonatite and melilitite liquids which were physically separated before the eruption. Abundant mantle xenoliths are direct evidence of the deep-seated origin of the parental magma and its high velocity of propagation towards the surface. Often, these nodules form the core of lapilli composed of concentric shells of melilitite and/or porphyritic carbonatite. Coarse-ash beds alternate with lapilli beds and consist of abundant lumps and spherulae of very fine-grained calcite immersed in a welded, highly compacted carbonatite matrix. Porphyritic carbonatite shells of the lapilli and fine-grained spherulae of calcite in the tuff matrix suggest incipient crystallisation of a carbonatite liquid in subvolcanic conditions and eruption of carbonatite-spray droplets. Dark coloured juvenile fragments mainly consist of melilite, phlogopite, calcite, apatite, perovskite, and häuyne crystals in a carbonatite or melilitite matrix. The rocks have an extremely primitive, ultramafic composition with very high Mg# (> 85) and Cr and Ni content (1500 ppm). The calcite contains high SrO, BaO and REE of up to 1.5 wt.%. Similar compositions are typical of primary, magmatic carbonates which are found in both intrusive and extrusive carbonatites. The high modal Sr

  18. Great Lakes Literacy Principles

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

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

  19. The Key Lake project

    1991-01-01

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  20. Geochronology and paleoenvironment of pluvial Harper Lake, Mojave Desert, California, USA

    Garcia, Anna L.; Knott, Jeffrey R.; Mahan, Shannon; Bright, Jordan

    2014-01-01

    Accurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes (Limnocythere ceriotuberosa) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.

  1. Continental-scale patterns of nutrient and fish effects on shallow lakes: synthesis of a pan-European mesocosm experiment

    Moss, B.; Stephen, D.; Balayla, D.; Bécares, E.; Collings, S.E.; Fernández-Aláez, C.; Fernández-Aláez, M.; Ferriol, C.; García, P.; Gomá, J.; Gyllström, M.; Hansson, L-A.; Hietala, J.; Kairesalo, T.; Rosa Miracle, M.; Romo, S.; Rueda, J.; Russell, V.; Ståhl-Delbanco, A.; Svensson, M.; Vakkilainen, K.; Valentín, M.; van de Bund, W.; Van Donk, E.; Vicente, E.; Villena, M.J.

    2004-01-01

    1. Results are analysed from 11 experiments in which effects of fish addition and nutrient loading on shallow lakes were studied in mesocosms. The experiments, five in 1998, six in 1999, were carried out in six lakes, distributed from Finland to southern Spain, according to a standard protocol. 2.

  2. Surface faults in the gulf coastal plain between Victoria and Beaumont, Texas

    Verbeek, Earl R.

    1979-01-01

    Displacement of the land surface by faulting is widespread in the Houston-Galveston region, an area which has undergone moderate to severe land subsidence associated with fluid withdrawal (principally water, and to a lesser extent, oil and gas). A causative link between subsidence and fluid extraction has been convincingly reported in the published literature. However, the degree to which fluid withdrawal affects fault movement in the Texas Gulf Coast, and the mechanism(s) by which this occurs are as yet unclear. Faults that offset the ground surface are not confined to the large (>6000-km2) subsidence “bowl” centered on Houston, but rather are common and characteristic features of Gulf Coast geology. Current observations and conclusions concerning surface faults mapped in a 35,000-km2 area between Victoria and Beaumont, Texas (which area includes the Houston subsidence bowl) may be summarized as follows: (1) Hundreds of faults cutting the Pleistocene and Holocene sediments exposed in the coastal plain have been mapped. Many faults lie well outside the Houston-Galveston region; of these, more than 10% are active, as shown by such features as displaced, fractured, and patched road surfaces, structural failure of buildings astride faults, and deformed railroad tracks. (2) Complex patterns of surface faults are common above salt domes. Both radial patterns (for example, in High Island, Blue Ridge, Clam Lake, and Clinton domes) and crestal grabens (for example, in the South Houston and Friendswood-Webster domes) have been recognized. Elongate grabens connecting several known and suspected salt domes, such as the fault zone connecting Mykawa, Friendswood-Webster, and Clear Lake domes, suggest fault development above rising salt ridges. (3) Surface faults associated with salt domes tend to be short (10 km), occur singly or in simple grabens, have gently sinuous traces, and tend to lie roughly parallel to the ENE-NE “coastwise” trend common to regional growth

  3. Comparing electricity distribution network revenues and costs in New South Wales, Great Britain and Victoria

    Mountain, Bruce; Littlechild, Stephen

    2010-01-01

    A decade ago, electricity distribution network revenues per customer in New South Wales (NSW) were twice those in Great Britain (GB). Recent price controls imply that by 2014 they will be nearly four times as high. This paper examines possible reasons for this. The main reason does not seem to be geography, operating environment or industry structure. GB and Victoria have managed to accommodate increasing demand at broadly constant or even declining costs and revenues while delivering higher quality of service, while NSW has not. The regulatory framework and the practice of the regulatory body within that framework seem relevant. Australian regulators have not used benchmarking techniques as the GB regulator has. Perhaps the most important explanatory factor is private ownership in GB and Victoria compared to state ownership in NSW. This could also impact on the nature and effectiveness of regulation. (author)

  4. Towards understanding hydroclimatic change in Victoria, Australia – preliminary insights into the "Big Dry"

    A. S. Kiem

    2010-03-01

    Full Text Available Since the mid-1990s the majority of Victoria, Australia, has experienced severe drought conditions (i.e. the "Big Dry" characterized by streamflow that is the lowest in approximately 80 years of record. While decreases in annual and seasonal rainfall totals have also been observed, this alone does not seem to explain the observed reduction in flow. In this study, we investigate the large-scale climate drivers for Victoria and demonstrate how these modulate the regional scale synoptic patterns, which in turn alter the way seasonal rainfall totals are compiled and the amount of runoff per unit rainfall that is produced. The hydrological implications are significant and illustrate the need for robust hydrological modelling, that takes into account insights into physical mechanisms that drive regional hydroclimatology, in order to properly understand and quantify the impacts of climate change (natural and/or anthropogenic on water resources.

  5. Use of regionalisation approach to develop fire frequency curves for Victoria, Australia

    Khastagir, Anirban; Jayasuriya, Niranjali; Bhuyian, Muhammed A.

    2017-11-01

    It is important to perform fire frequency analysis to obtain fire frequency curves (FFC) based on fire intensity at different parts of Victoria. In this paper fire frequency curves (FFCs) were derived based on forest fire danger index (FFDI). FFDI is a measure related to fire initiation, spreading speed and containment difficulty. The mean temperature (T), relative humidity (RH) and areal extent of open water (LC2) during summer months (Dec-Feb) were identified as the most important parameters for assessing the risk of occurrence of bushfire. Based on these parameters, Andrews' curve equation was applied to 40 selected meteorological stations to identify homogenous stations to form unique clusters. A methodology using peak FFDI from cluster averaged FFDIs was developed by applying Log Pearson Type III (LPIII) distribution to generate FFCs. A total of nine homogeneous clusters across Victoria were identified, and subsequently their FFC's were developed in order to estimate the regionalised fire occurrence characteristics.

  6. Southern blotting.

    Brown, T

    2001-05-01

    Southern blotting is the transfer of DNA fragments from an electrophoresis gel to a membrane support (the properties and advantages of the different types of membrane, transfer buffer, and transfer method are discussed in detail), resulting in immobilization of the DNA fragments, so the membrane carries a semipermanent reproduction of the banding pattern of the gel. After immobilization, the DNA can be subjected to hybridization analysis, enabling bands with sequence similarity to a labeled probe to be identified. This appendix describes Southern blotting via upward capillary transfer of DNA from an agarose gel onto a nylon or nitrocellulose membrane, using a high-salt transfer buffer to promote binding of DNA to the membrane. With the high-salt buffer, the DNA becomes bound to the membrane during transfer but not permanently immobilized. Immobilization is achieved by UV irradiation (for nylon) or baking (for nitrocellulose). A Support Protocol describes how to calibrate a UV transilluminator for optimal UV irradiation of a nylon membrane. An alternate protocol details transfer using nylon membranes and an alkaline buffer, and is primarily used with positively charged nylon membranes. The advantage of this combination is that no post-transfer immobilization step is required, as the positively charged membrane binds DNA irreversibly under alkaline transfer conditions. The method can also be used with neutral nylon membranes but less DNA will be retained. A second alternate protocol describes a transfer method based on a different transfer-stack setup. The traditional method of upward capillary transfer of DNA from gel to membrane described in the first basic and alternate protocols has certain disadvantages, notably the fact that the gel can become crushed by the weighted filter papers and paper towels that are laid on top of it. This slows down the blotting process and may reduce the amount of DNA that can be transferred. The downward capillary method described in

  7. Limnology of Eifel maar lakes

    Scharf, Burkhard W; Björk, Sven

    1992-01-01

    ... : Species composition & seasonal periodicity - Qualitative & quantitative investigations on cladoceran zooplankton of oligotrophic maar lakes - Population dynamics of pelagic copepods in maar lakes - Population dynamics...

  8. An investigation of the structure beneath Magadi area in southern ...

    Magadi area is located in the southern part of the Kenyan rift, an active continental rift that is part of the East African Rift system. Local seismic activity monitored previously around Lake Magadi revealed an earthquake cluster caused by swarm activity in the rift centre at shallow depths, which was probably triggered by ...

  9. Critical influences on succession management for non-commissioned ranks within Victoria police

    Owbridge, Lynne Michelle

    2017-01-01

    This thesis examines issues affecting succession management within noncommissioned ranks (NCRs) of policing services. Using Victoria Police (VicPol) as a case study, this research explored the organisation's capacity to build individual and organisational capability through adequate recruitment of new police, professional learning, and retaining talent within NCRs. A grounded theory approach was used to explore VicPol's recruitment, foundation training, transfer, promotion, ...

  10. NAPLAN Scores as Predictors of Access to Higher Education in Victoria

    Brendan Houng; Moshe Justman

    2014-01-01

    This paper examines the extent to which year-9 performance on the National Assessment Program—Language Arts and Numeracy (NAPLAN) predicts access to higher education as determined by subsequent achievement on year-12 Victoria Certificate of Education (VCE) exams. VCE performance is measured via three binary indicators: achieving an Australian tertiary admission rank (ATAR) above 50 ("ATAR50"), above 70 ("ATAR70"), and above 90 ("ATAR90"); and two continuous indicators: ATAR and the Tertiary E...

  11. A Comparison of digestive Tract Morphology in muskoxen and caribou from Victoria Island, Northwest Territories, Canada

    Hans Staaland

    1997-04-01

    Full Text Available Although caribou and muskoxen coexist in close proximity on southeastern Victoria Island, they appear primarily adapted to different diets and foraging strategies. Visual inspection and analysis of rumen contents for fiber and lignin from the study (unpubl. also indicate a predominantly graminoid diet in the muskoxen and a more varied diet with a substantial browse component in the caribou.This should reduce the likelihood of competition for limited food resources in winter.

  12. Hospital-treated injuries from horse riding in Victoria, Australia: time to refocus on injury prevention?

    O'Connor, Siobhán; Hitchens, Peta L; Fortington, Lauren V

    2018-01-01

    The most recent report on hospital-treated horse-riding injuries in Victoria was published 20 years ago. Since then, injury countermeasures and new technology have aimed to make horse riding safer for participants. This study provides an update of horse-riding injuries that required hospital treatment in Victoria and examines changes in injury patterns compared with the earlier study. Horse-riding injuries that required hospital treatment (hospital admission (HA) or emergency department (ED) presentations) were extracted from routinely collected data from public and private hospitals in Victoria from 2002-2003 to 2015-2016. Injury incidence rates per 100 000 Victorian population per financial year and age-stratified and sex-stratified injury incidence rates are presented. Poisson regression was used to examine trends in injury rates over the study period. ED presentation and HA rates were 31.1 and 6.6 per 100 000 person-years, increasing by 28.8% and 47.6% from 2002 to 2016, respectively. Female riders (47.3 ED and 10.1 HA per 100 000 person-years) and those aged between 10 and 14 years (87.8 ED and 15.7 HA per 100 000 person-years) had the highest incidence rates. Fractures (ED 29.4%; HA 56.5%) and head injuries (ED 15.4%; HA 18.9%) were the most common injuries. HA had a mean stay of 2.6±4.1 days, and the mean cost per HA was $A5096±8345. Horse-riding injuries have remained similar in their pattern (eg, types of injuries) since last reported in Victoria. HA and ED incidence rates have increased over the last 14 years. Refocusing on injury prevention countermeasures is recommended along with a clear plan for implementation and evaluation of their effectiveness in reducing injury.

  13. A real-options analysis of wine grape farming in north west Victoria

    Seyoum, Emayenesh; Chan, Chris

    2012-01-01

    This paper reports a use of a real-options valuation methodology to analyse wine grape farm investment under price and yield uncertainty. Revenue levels to incentivise entry and exit were calculated for three different sizes of wine grape farms in North West Victoria. The modelling identified lower exit and higher entry triggers than indicated by conventional net present value calculation. The wide gap of estimated indeterminacy in farm investment highlights the intertwined influence of numer...

  14. ‘A token of their love’: Queen Victoria Memorials in New Zealand

    Stocker, Mark

    2016-01-01

    This article provides an overview of the four metropolitan sculptural memorials to Queen Victoria in late-colonial New Zealand, which all immediately precede the colony’s Dominion status (1907). In chronological order, they were erected in Auckland, Christchurch, Wellington, and Dunedin. While the Auckland memorial was unveiled within the Queen’s lifetime, her death in 1901 catalysed the commission of more ambitious counterparts in Wellington and Dunedin, and a degree of intercity rivalry was...

  15. A Review of the Taxation of Property: Local Government Rates in Victoria 1

    Johnson, David T.

    1993-01-01

    The paper reviews the taxation of property in Victoria and in particular the method of raising revenue for local government from rural landowners. A major contradiction between the apparent philosophical basis and its application is identified. A modification to the existing method of calculation is suggested based on the use value of rural land. The advantages and disadvantages of the use value modification are discussed and compared to the system of property taxes presently used. The use me...

  16. Adverse events in surgical inpatients: A comparative analysis of public hospitals in Victoria

    Katharina Hauck; Xueyan Zhao; Terri Jackson

    2010-01-01

    We compare adverse event rates for surgical inpatients across 36 public hospitals in the state of Victoria, Australia, conditioning on differences in patient complexity across hospitals. We estimate separate models for elective and emergency patients which stay at least one night in hospitals, using fixed effects complementary log-log models to estimate AEs as a function of patient and episode characteristics, and hospital effects. We use 4 years of patient level administrative hospital data ...

  17. The reduction of the intrapartum still birth rate at the Queen Victoria Memorial Hospital.

    Anderson, I; Chang, A; Renou, P; Wood, C

    1977-06-18

    A significant reduction in intrapartum anoxic fetal deaths has occurred at the Queen Victoria Memorial Hospital over the last ten years. The possible explanations for this include a variety of factors, which may either improve the health of the population presenting to the hospital, or improve obstetric care. Epidemiological evidence suggests that the use of fetal diagnostic techniques has contributed to the reduction of intrapartum anoxic still births.

  18. The origins of the Frente para la Victoria in Argentina (1988-2003

    Pamela SOSA

    2017-10-01

    Full Text Available The article reconstructs the trajectory of the Frente para la Victoria in the Argentinean province of Santa Cruz between 1988 y 2003. Period during which this political force was formed, forged its main attributes and amass the political capital that allow it to reach the presidency of the Nation in 2003, position that holds to December 2015. This organization was built outside the dominant structures and groups of the provincial politics.

  19. Lakes, Lagerstaetten, and Evolution

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

    2001-12-01

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

  20. Patterns in the Physical, Chemical, and Biological Composition of Icelandic Lakes and the Dominant Factors Controlling Variability Across Watersheds

    Greco, A.; Strock, K.; Edwards, B. R.

    2017-12-01

    Fourteen lakes were sampled in the southern and western area of Iceland in June of 2017. The southern systems, within the Eastern Volcanic Zone, have minimal soil development and active volcanoes that produce ash input to lakes. Lakes in the Western Volcanic Zone were more diverse and located in older bedrock with more extensively weathered soil. Physical variables (temperature, oxygen concentration, and water clarity), chemical variables (pH, conductivity, dissolved and total nitrogen and phosphorus concentrations, and dissolved organic carbon concentration), and biological variables (algal biomass) were compared across the lakes sampled in these geographic regions. There was a large range in lake characteristics, including five to eighteen times higher algal biomass in the southern systems that experience active ash input to lakes. The lakes located in the Eastern Volcanic Zone also had higher conductivity and lower pH, especially in systems receiving substantial geothermal input. These results were analyzed in the context of more extensive lake sampling efforts across Iceland (46 lakes) to determine defining characteristics of lakes in each region and to identify variables that drive heterogeneous patterns in physical, chemical, and biological lake features within each region. Coastal systems, characterized by high conductivity, and glacially-fed systems, characterized by high iron concentrations, were unique from lakes in all other regions. Clustering and principal component analyses revealed that lake type (plateau, valley, spring-fed, and direct-runoff) was not the primary factor explaining variability in lake chemistry outside of the coastal and glacial lake types. Instead, lakes differentiated along a gradient of iron concentration and total nitrogen concentration. The physical and chemical properties of subarctic lakes are especially susceptible to both natural and human-induced environmental impacts. However, relatively little is known about the

  1. Potentially avoidable hospitalisation for constipation in Victoria, Australia in 2010-11.

    Ansari, Humaira; Ansari, Zahid; Hutson, John M; Southwell, Bridget R

    2014-07-11

    When primary care of constipation fails, the patient may need emergency hospitalisation for disimpaction. This study aimed to provide population-based data on the number of unplanned admissions and the cost to the healthcare system for constipation in Victoria, Australia in financial year 2010-11. The Victorian Admitted Episodes Dataset was examined to find the number of emergency hospital separations coded as constipation (ICD-10-AM Code K390). An estimate of costs was determined from the number of weighted inlier equivalent separations (WIES) multiplied by the WEIS price, used by the Victorian Government for funding purposes. There were 3978 emergency separations for constipation in Victoria in 2010-2011, 92% in public hospitals. Fifty-five percent were female and 38% > 75 years old. One third stayed overnight and 1/3 more than 1 day. The emergency bed day rate was 7.1 per 10,000 of population. The estimate of cost, based on WEIS, was approximately $8.3 million. Potential savings could be made by reducing the number of separations in 6 Local Government Areas (LGAs). This study shows that the burden (in number of admissions, emergency bed days and overall direct costs) in managing emergency admissions for constipation in Victoria, Australia, is very significant and likely to be similar in other developed countries. Improved primary healthcare and alternative ways to achieve faecal disimpaction without emergency admission could save the public health system a proportion of this $8.3 million.

  2. Geology and environments of subglacial Lake Vostok.

    Leitchenkov, German L; Antonov, Anton V; Luneov, Pavel I; Lipenkov, Vladimir Ya

    2016-01-28

    The reconstruction of the geological (tectonic) structure and environments of subglacial Lake Vostok is based on geophysical surveys and the study of mineral particles found in cores of accreted ice and frozen lake water (sampled after the lake was unsealed). Seismic reflection and refraction investigations conducted in the southern part of Lake Vostok show very thin (200-300 m) sedimentary cover overlying a crystalline basement. Most of this thin veneer is thought to have been deposited during temperate-glacial conditions in Oligocene to Middle Miocene time (ca 34-14 Ma). The composition of the lake-bottom sediments can be deduced from mineral inclusions found in cores of accreted ice. Inclusions are represented by soft aggregates consisting mainly of clay-mica minerals and micrometre-sized quartz grains. Some of these inclusions contain subangular to semi-rounded rock clasts (siltstones and sandstones) ranging from 0.3 to 8 mm in size. In total, 31 zircon grains have been identified in two rock clasts and dated using SHRIMP-II. The ages of the studied zircons range from 0.6 to 2.0 Ga with two distinct clusters between 0.8 and 1.15 Ga and between 1.6 and 1.8 Ga. Rock clasts obviously came from the western lake shore, which is thus composed of terrigenous strata with an age of not older than 600 Ma. The sedimentary nature of the western lake shore is also confirmed by seismic refraction data showing seismic velocities there of 5.4-5.5 km s(-1) at the bedrock surface. After Lake Vostok was unsealed, its water (frozen and sampled next season) was also studied with scanning electron microscopy and X-ray microprobe analysis. This study showed the existence of calcium carbonate and silica microparticles (10-20 μm across) in frozen water. © 2015 The Author(s).

  3. Ecology of Meromictic Lakes

    Gulati, R.D.; Zadereev, E.S.; Degermendzhy, A.G.

    2017-01-01

    This volume presents recent advances in the research on meromictic lakes and a state-of-the art overview of this area. After an introduction to the terminology and geographic distribution of meromictic lakes, three concise chapters describe their physical, chemical and biological features. The

  4. Determinism in fish assemblages of floodplain lakes of the vastly disturbed Mississippi Alluvial Valley

    Miranda, L.E.; Lucas, G.M.

    2004-01-01

    The Mississippi Alluvial Valley between southern Illinois and southern Louisiana contains hundreds of floodplain lakes, most of which have been adversely affected by landscape modifications used to control flooding and support agriculture. We examined fish assemblages in lakes of this region to determine whether deterministic patterns developed in relation to prominent abiotic lake characteristics and to explore whether relevant abiotic factors could be linked to specific assemblage structuring mechanisms. The distributions of 14 taxa in 29 lakes were governed primarily by two gradients that contrasted assemblages in terms of lake area, lake elongation, and water clarity. The knowledge of whether a lake was clear or turbid, large or small, and long or short helped determine fish assemblage characteristics. Abiotic factors influenced fish assemblage structures, plausibly through limitations on foraging and physiological tolerances. Determinism in assemblage organization of floodplain lakes relative to recurrence in physicochemical features has been documented for unaltered rivers. Whereas the Mississippi Alluvial Valley has been subjected to vast anthropogenic disturbances and is not a fully functional floodplain river, fish assemblages in its floodplain lakes remain deterministic and organized by the underlying factors that also dictate assemblages in unaltered rivers. In advanced stages of lake aging, fish assemblages in these lakes are expected to largely include species that thrive in turbid, shallow systems with few predators and low oxygen concentrations. The observed patterns related to physical characteristics of these lakes suggest three general conservation foci, including (1) watershed management to control erosion, (2) removal of sediments or increases in water level to alleviate depth reductions and derived detriments to water physicochemistry, and (3) management of fish populations through stockings, removals, and harvest regulations.

  5. Light attenuation in estuarine mangrove lakes

    Frankovich, Thomas A.; Rudnick, David T.; Fourqurean, James W.

    2017-01-01

    Submerged aquatic vegetation (SAV) cover has declined in brackish lakes in the southern Everglades characterized by low water transparencies, emphasizing the need to evaluate the suitability of the aquatic medium for SAV growth and to identify the light attenuating components that contribute most to light attenuation. Underwater attenuation of downwards irradiance of photosynthetically active radiation (PAR) was determined over a three year period at 42 sites in shallow (freshwater flow into these areas may dilute CDOM concentrations and improve the salinity and light climate for SAV communities.

  6. Lake Urmia (Iran): can future socio-ecologically motivated river basin management restore lake water levels in an arid region with extensive agricultural development?

    Fazel, Nasim; Berndtsson, Ronny; Bertacchi Uvo, Cintia; Klove, Bjorn; Madani, Kaveh

    2015-04-01

    Lake Urmia, one of the world's largest hyper saline lakes located in northwest of Iran, is a UNESCO Biosphere Reserve and Ramsar site, protected as a national park and, supports invaluable and unique biodiversity and related ecosystem services for the region's 6.5 million inhabitants. Due to increased development of the region's water resources for agriculture and industry and to a certain extent climate change, the lake has started to shrink dramatically since 1995 and now is holding less than 30 percent of its volume. Rapid development in agricultural sector and land-use changes has resulted in immense construction of dams and water diversions in almost all lake feeding rivers, intensifying lake shrinking, increasing salinity and degrading its ecosystem. Recently, lake's cultural and environmental importance and social pressure has raised concerns and brought government attention to the lake restoration plans. Along with poor management, low yield agriculture as the most water consuming activity in the region with, rapid, insufficient development is one of the most influential drivers in the lake desiccation. Part of the lake restoration plans in agricultural sector is to restrict the agricultural areas in the main feeding river basins flowing mostly in the southern part of the lake and decreasing the agricultural water use in this area. This study assess the efficiency and effectiveness of the proposed plans and its influence on the lake level rise and its impacts on economy in the region using a system dynamics model developed for the Lake consist of hydrological and agro-economical sub-systems. The effect of decrease in agricultural area in the region on GDP and region economy was evaluated and compared with released water contribution in lake level rise for a five year simulation period.

  7. Lake Afdera: a threatened saline lake in Ethiopia | Getahun | SINET ...

    Lake Afdera is a saline lake located in the Afar region, Northern Ethiopia. Because of its inaccessibility it is one of the least studied lakes of the country. It supports life including three species of fish of which two are endemic. Recently, reports are coming out that this lake is used for salt extraction. This paper gives some ...

  8. Comparison of mortality following hospitalisation for isolated head injury in England and Wales, and Victoria, Australia.

    Belinda J Gabbe

    Full Text Available BACKGROUND: Traumatic brain injury (TBI remains a leading cause of death and disability. The National Institute for Health and Clinical Excellence (NICE guidelines recommend transfer of severe TBI cases to neurosurgical centres, irrespective of the need for neurosurgery. This observational study investigated the risk-adjusted mortality of isolated TBI admissions in England/Wales, and Victoria, Australia, and the impact of neurosurgical centre management on outcomes. METHODS: Isolated TBI admissions (>15 years, July 2005-June 2006 were extracted from the hospital discharge datasets for both jurisdictions. Severe isolated TBI (AIS severity >3 admissions were provided by the Trauma Audit and Research Network (TARN and Victorian State Trauma Registry (VSTR for England/Wales, and Victoria, respectively. Multivariable logistic regression was used to compare risk-adjusted mortality between jurisdictions. FINDINGS: Mortality was 12% (749/6256 in England/Wales and 9% (91/1048 in Victoria for isolated TBI admissions. Adjusted odds of death in England/Wales were higher compared to Victoria overall (OR 2.0, 95% CI: 1.6, 2.5, and for cases <65 years (OR 2.36, 95% CI: 1.51, 3.69. For severe TBI, mortality was 23% (133/575 for TARN and 20% (68/346 for VSTR, with 72% of TARN and 86% of VSTR cases managed at a neurosurgical centre. The adjusted mortality odds for severe TBI cases in TARN were higher compared to the VSTR (OR 1.45, 95% CI: 0.96, 2.19, but particularly for cases <65 years (OR 2.04, 95% CI: 1.07, 3.90. Neurosurgical centre management modified the effect overall (OR 1.12, 95% CI: 0.73, 1.74 and for cases <65 years (OR 1.53, 95% CI: 0.77, 3.03. CONCLUSION: The risk-adjusted odds of mortality for all isolated TBI admissions, and severe TBI cases, were higher in England/Wales when compared to Victoria. The lower percentage of cases managed at neurosurgical centres in England and Wales was an explanatory factor, supporting the changes made to the NICE

  9. Carbon and phosphorus regulating bacterial metabolism in oligotrophic boreal lakes

    Vidal, L. O.; Graneli, W.; Daniel, C. B.

    2011-01-01

    This study focused on how phosphorus and carbon control pelagic bacteria in lakes over a gradient of dissolved organic carbon (DOC from 6.7 to 29.5 mg C L(-1)) and phosphorus (P-tot from 5 to 19 mu g L(-1)). Five oligotrophic lakes in southern Sweden were sampled in late autumn. Phosphate...... carbon mineralization in this kind of system during autumn is conditioned by the combined availability of labile carbon and phosphorus, with the assimilated carbon mainly transformed to inorganic carbon in respiration, contributing to CO(2) supersaturation in these systems....

  10. Isotopic tracers of paleohydrologic change in large lakes of the Bolivian Altiplano

    Placzek, Christa J.; Quade, Jay; Patchett, P. Jonathan

    2011-01-01

    We have developed an 87Sr/ 86Sr, 234U/ 238U, and δ 18O data set from carbonates associated with late Quaternary paleolake cycles on the southern Bolivian Altiplano as a tool for tracking and understanding the causes of lake-level fluctuations. Distinctive groupings of 87Sr/ 86Sr ratios are observed. Ratios are highest for the Ouki lake cycle (120-95 ka) at 0.70932, lowest for Coipasa lake cycle (12.8-11.4 ka) at 0.70853, and intermediate at 0.70881 to 0.70884 for the Salinas (95-80 ka), Inca Huasi (~ 45 ka), Sajsi (24-20.5 ka), and Tauca (18.1-14.1 ka) lake cycles. These Sr ratios reflect variable contributions from the eastern and western Cordilleras. The Laca hydrologic divide exerts a primary influence on modern and paleolake 87Sr/ 86Sr ratios; waters show higher 87Sr/ 86Sr ratios north of this divide. Most lake cycles were sustained by slightly more rainfall north of this divide but with minimal input from Lake Titicaca. The Coipasa lake cycle appears to have been sustained mainly by rainfall south of this divide. In contrast, the Ouki lake cycle was an expansive lake, deepest in the northern (Poópo) basin, and spilling southward. These results indicate that regional variability in central Andean wet events can be reconstructed using geochemical patterns from this lake system.

  11. The influence of climate change to European Lakes, with a special emphasis in the Balkan Region

    Kuusisto, Esko

    2004-01-01

    There are almost one and half million lakes in Europe, if small water bodies with an area down to 0.001 km 2 are included. The total area of lakes is over 200.000 km 2 , in addition the man-made reservoirs cover almost 100.000 km 2 . The largest lakes are located in the zone extending from southwestern Sweden through Finland to Russia, but there are many important lakes also in central and southern Europe. The Balkan countries have altogether about ten thousand lakes with a total area of over 4000 km 2 and total volume of almost loo km 3 . Over half of the total volume is in Lake Ohrid, which ranks the seventh in Europe both as to the volume and as to the maximum depth. However, there are around thirty lakes in Europe with their surface area larger than that of Lake Ohrid. In addition to the lakes, the Balkan countries also have thousands of reservoirs with a total water storage capacity of over 50 km 3 . The response of European lakes to climate change can be discussed by dividing the lakes into five categories: 1) deep temperate lakes, 2) shallow temperate lakes, 3) mountain lakes, 4) boreal lakes and 5) arctic lakes. The lakes in the Balkan region fall belong into the first three categories. Most of the deep temperate lakes are warm monomictic; convective overturn occurs in winter or early spring. The future climate change may suppress this overturn, giving these lakes the classification of oligomictic. This implies the enhancement of anoxic bottom conditions and an increased risk of eutrophication. The oxygen conditions can also be expected to deteriorate due to increased bacterial activity in deep waters and superficial bottom sediment. In shallow temperate lakes, higher water temperatures in the future will induce intensified primary production and bacterial decomposition. The probability of harmful extreme events, e.g. the mass production of algae, will increase. The impacts may extend to fishing and recreational use. In lakes with relatively long water

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

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

    2006-01-01

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

  13. Yellowstone Lake Nanoarchaeota

    Scott eClingenpeel

    2013-09-01

    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  14. Whiting in Lake Michigan

    2002-01-01

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

  15. Influence of permafrost on lake terraces of Lake Heihai (NE Tibetan Plateau)

    Lockot, Gregori; Hartmann, Kai; Wünnemann, Bernd

    2013-04-01

    The Tibetan Plateau (TP) is one of the key regions for climatic global change. Besides the poles the TP is the third highest storage of frozen water in glaciers. Here global warming is three times higher than in the rest of the world. Additionally the TP provides water for billions of people and influences the moisture availability from the Indian and East Asian monsoon systems. During the Holocene extent and intensity of the monsoonal systems changed. Hence, in the last decades, a lot of work was done to reconstruct timing and frequency of monsoonal moisture, to understand the past and give a better forecast for the future. Comparative workings often show very heterogeneous patterns of timing and frequency of the Holocene precipitation and temperature maximum, emphasizing the local importance of catchment dynamics. In this study we present first results of lake Heihai (36°N, 93°15'E, 4500m a.s.l.), situated at the north-eastern border of the TP. The lake is surrounded by a broad band of near-shore lake sediments, attesting a larger lake extent in the past. These sediments were uplifted by permafrost, reaching nowadays heights ca. +8 meters above present lake level. Due to the uplift one of the main inflows was blocked and the whole hydrology of the catchment changed. To quantify the uplift of permafrost Hot Spot Analysis were accomplished at a DEM of the near-shore area. As a result regions of high permafrost uplift and those which mirror the original height of lake ground were revealed. The most obvious uplift took place in the northern and western part of the lake, where the four uplift centers are located. In contrast the southern and eastern areas show a rather degraded pattern (probably by fluvial erosion, thermokarst, etc.). The ancient lake bottom, without permafrost uplift was estimated to be 4-6 meters above the modern lake level. For a better understanding of permafrost interaction inside the terrace bodies a 5m sediment profile was sampled and

  16. 137Cs as a tracer of recent sedimentary processes in Lake Michigan

    Cahill, R.A.; Steele, J.D.

    1986-01-01

    To determine recent sediment movement, we measured the levels of 137Cs (an artificial radionuclide produced during nuclear weapons testing) of 118 southern Lake Michigan samples and 27 in Green Bay. These samples, taken from 286 grab samples of the upper 3 cm of sediment, were collected in 1975 as part of a systematic study of Lake Michigan sediment. 137Cs levels correlated well with concentrations of organic carbon, lead, and other anthropogenic trace metals in the sediment. 137Cs had a higher correlation with silt-sized than with clay-sized sediment (0.55 and 0.46, respectively). Atmospherically derived 137Cs and trace metals are being redistributed by sedimentary processes in Lake Michigan after being incorporated in suspended sediment. We determined a distribution pattern of 137Cs that represents areas of southern Lake Michigan where sediment deposition is occurring. ?? 1986 Dr W. Junk Publishers.

  17. Mercury biomagnification in the food web of Lake Tanganyika (Tanzania, East Africa)

    Campbell, L. [School of Environmental Studies and Department of Biology, Queen' s University, Kingston, Ontario, K7L-3N6 (Canada)], E-mail: linda.campbell@queensu.ca; Verburg, Piet [National Institute of Water and Atmospheric Research, PO Box 11-115, Hamilton 3251 (New Zealand); Dixon, D.G. [Department of Biology, University of Waterloo, 200 University Avenue, Waterloo (Canada); Hecky, R.E. [Large Lakes Observatory, University of Minnesota, Duluth, 10 University Drive 204 RLBDuluth, MN 55812-2496 (United States)

    2008-09-01

    Lake Tanganyika is a globally important lake with high endemic biodiversity. Millions of people in the lake basin depend on several fish species for consumption. Due to the importance of fish consumption as an exposure route of mercury to humans, we sampled Lake Tanganyika in 2000 to assess total mercury concentrations and biomagnification of total mercury through the food web. Stable nitrogen and carbon isotope analyses of food web structure indicate a complex food web with overlapping omnivory with some specialist fish species. Stable nitrogen isotope analyses further confirm that mercury is biomagnifying through the Tanganyika food web at rates similar to those seen in Lakes Malawi and Victoria, the other two African Great Lakes. Most collected fish species and all invertebrate species had mercury concentrations below 0.2 {mu}g Hg/g wet weight. However, several fish species, Ctenochromis horei (average 0.15 {mu}g/g ww), Neolamprologus boulengeri (0.2 {mu}g/g ww) , Bathybates spp.spp. (0.21 {mu}g/g ww), Mastacembelus cunningtoni (0.22 {mu}g/g ww) and Clarias theodorae (0.22 {mu}g/g ww) approached or slightly exceeded the World Health Organization (WHO)'s recommended guideline of 0.2 {mu}g Hg/g for vulnerable populations with high rates of fish consumption. Two individuals of the piscivorous fish species Lates microlepis (0.54, 0.78 {mu}g/g ww) and a Polypterus congicus (1.3 {mu}g/g ww) exceeded the international marketing limit value of 0.5 {mu}g/g ww. Because C. theodorae and L. microlepis are also important market fish species, there is a need to monitor mercury concentrations in internationally marketed fish from Lake Tanganikya to ensure that those fish do not present a risk to human consumers.

  18. Mercury biomagnification in the food web of Lake Tanganyika (Tanzania, East Africa)

    Campbell, L.; Verburg, Piet; Dixon, D.G.; Hecky, R.E.

    2008-01-01

    Lake Tanganyika is a globally important lake with high endemic biodiversity. Millions of people in the lake basin depend on several fish species for consumption. Due to the importance of fish consumption as an exposure route of mercury to humans, we sampled Lake Tanganyika in 2000 to assess total mercury concentrations and biomagnification of total mercury through the food web. Stable nitrogen and carbon isotope analyses of food web structure indicate a complex food web with overlapping omnivory with some specialist fish species. Stable nitrogen isotope analyses further confirm that mercury is biomagnifying through the Tanganyika food web at rates similar to those seen in Lakes Malawi and Victoria, the other two African Great Lakes. Most collected fish species and all invertebrate species had mercury concentrations below 0.2 μg Hg/g wet weight. However, several fish species, Ctenochromis horei (average 0.15 μg/g ww), Neolamprologus boulengeri (0.2 μg/g ww) , Bathybates spp.spp. (0.21 μg/g ww), Mastacembelus cunningtoni (0.22 μg/g ww) and Clarias theodorae (0.22 μg/g ww) approached or slightly exceeded the World Health Organization (WHO)'s recommended guideline of 0.2 μg Hg/g for vulnerable populations with high rates of fish consumption. Two individuals of the piscivorous fish species Lates microlepis (0.54, 0.78 μg/g ww) and a Polypterus congicus (1.3 μg/g ww) exceeded the international marketing limit value of 0.5 μg/g ww. Because C. theodorae and L. microlepis are also important market fish species, there is a need to monitor mercury concentrations in internationally marketed fish from Lake Tanganikya to ensure that those fish do not present a risk to human consumers

  19. Climate change forces new ecological states in tropical Andean lakes.

    Neal Michelutti

    Full Text Available Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage of glaciers regionally. Using dated sediment cores from three lakes in the southern Sierra of Ecuador, we record abrupt increases in the planktonic thalassiosiroid diatom Discostella stelligera from trace abundances to dominance within the phytoplankton. This unprecedented shift occurs against the backdrop of rising temperatures, changing atmospheric pressure fields, and declining wind speeds. Ecological restructuring in these lakes is linked to warming and/or enhanced water column stratification. In contrast to seasonally ice-covered Arctic and temperate alpine counterparts, aquatic production has not increased universally with warming, and has even declined in some lakes, possibly because enhanced thermal stability impedes the re-circulation of hypolimnetic nutrients to surface waters. Our results demonstrate that these lakes have already passed important ecological thresholds, with potentially far-reaching consequences for Andean water resources.

  20. Spatial characterization of acid rain stress in Canadian Shield Lakes

    Tanis, Fred J.

    1987-01-01

    The acidification of lake waters from airborne pollution is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern U.S. and on the Canadian Shield is though to be enormous. How seasonal changes in lake transparency are related to annual acidic load was examined. The relationship between variations in lake acidification and ecophysical units was also examined. The utility of Thematic Mapper based observations to measure seasonal changes in the optical transparency in acid lakes was investigated. The potential for this optical response is related to a number of local ecophysical factors with bedrock geology being, perhaps, the most important. Other factors include sulfate deposition, vegetative cover, and terrain drainage/relief. The area of southern Ontario contains a wide variety of geologies from the most acid rain sensitive granite quartzite types to the least sensitive limestone dolomite sediments. Annual sulfate deposition ranges from 1.0 to 4.0 grams/sq m.