Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

Science.gov (United States)

Lin, Chen; Ma, Ronghua; He, Bin

2015-01-01

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

Science.gov (United States)

Lin, Chen; Ma, Ronghua; He, Bin

2015-12-24

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes

Science.gov (United States)

Filstrup, Christopher T.; Wagner, Tyler; Soranno, Patricia A.; Stanley, Emily H.; Stow, Craig A.; Webster, Katherine E.; Downing, John A.

2014-01-01

The relationship between chlorophyll a (Chl a) and total phosphorus (TP) is a fundamental relationship in lakes that reflects multiple aspects of ecosystem function and is also used in the regulation and management of inland waters. The exact form of this relationship has substantial implications on its meaning and its use. We assembled a spatially extensive data set to examine whether nonlinear models are a better fit for Chl a—TP relationships than traditional log-linear models, whether there were regional differences in the form of the relationships, and, if so, which regional factors were related to these differences. We analyzed a data set from 2105 temperate lakes across 35 ecoregions by fitting and comparing two different nonlinear models and one log-linear model. The two nonlinear models fit the data better than the log-linear model. In addition, the parameters for the best-fitting model varied among regions: the maximum and lower Chl aasymptotes were positively and negatively related to percent regional pasture land use, respectively, and the rate at which chlorophyll increased with TP was negatively related to percent regional wetland cover. Lakes in regions with more pasture fields had higher maximum chlorophyll concentrations at high TP concentrations but lower minimum chlorophyll concentrations at low TP concentrations. Lakes in regions with less wetland cover showed a steeper Chl a—TP relationship than wetland-rich regions. Interpretation of Chl a—TP relationships depends on regional differences, and theory and management based on a monolithic relationship may be inaccurate.

The influence of carbon exchange of a large lake on regional tracer-transport inversions: results from Lake Superior

International Nuclear Information System (INIS)

Vasys, Victoria N; Desai, Ankur R; McKinley, Galen A; Bennington, Val; Michalak, Anna M; Andrews, Arlyn E

2011-01-01

Large lakes may constitute a significant component of regional surface-atmosphere fluxes, but few efforts have been made to quantify these fluxes. Tracer-transport inverse models that infer the CO 2 flux from the atmospheric concentration typically assume that the influence from large lakes is negligible. CO 2 observations from a tall tower in Wisconsin segregated by wind direction suggested a CO 2 signature from Lake Superior. To further investigate this difference, source-receptor influence functions derived using a mesoscale transport model were applied and results revealed that air masses sampled by the tower have a transit time over the lake, primarily in winter when the total lake influence on the tower can exceed 20% of the total influence of the regional domain. When the influence functions were convolved with air-lake fluxes estimated from a physical-biogeochemical lake model, the overall total contribution of lake fluxes to the tall tower CO 2 were mostly negligible, but potentially detectable in certain periods of fall and winter when lake carbon exchange can be strong and land carbon efflux weak. These findings suggest that large oligotrophic lakes would not significantly influence inverse models that incorporate tall tower CO 2 .

Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

Science.gov (United States)

Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

2016-01-01

Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

Decadal oscillation of lakes and aquifers in the upper Great Lakes region of North America: hydroclimatic implications

Science.gov (United States)

Watras, C.J.; Read, J.S.; Holman, K.D.; Liu, Z.; Song, Y.-Y.; Watras, A.J.; Morgan, S.; Stanley, E.H.

2014-01-01

We report a unique hydrologic time-series which indicates that water levels in lakes and aquifers across the upper Great Lakes region of North America have been dominated by a climatically-driven, near-decadal oscillation for at least 70 years. The historical oscillation (~13y) is remarkably consistent among small seepage lakes, groundwater tables and the two largest Laurentian Great Lakes despite substantial differences in hydrology. Hydrologic analyses indicate that the oscillation has been governed primarily by changes in the net atmospheric flux of water (P-E) and stage-dependent outflow. The oscillation is hypothetically connected to large-scale atmospheric circulation patterns originating in the mid-latitude North Pacific that support the flux of moisture into the region from the Gulf of Mexico. Recent data indicate an apparent change in the historical oscillation characterized by a ~12y downward trend beginning in 1998. Record low water levels region-wide may mark the onset of a new hydroclimatic regime.

Lake Urmia (Iran): can future socio-ecologically motivated river basin management restore lake water levels in an arid region with extensive agricultural development?

Science.gov (United States)

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.

The emerging architecture of a regional security complex in the Lake ...

African Journals Online (AJOL)

This article explores the emerging regional security architecture to fight terrorism and insurgency in the Lake Chad Basin (LCB). It diagnoses the evolution of the Lake Chad Basin Commission (LCBC) as a sub-regional organization that unites Chad, Cameroon, Niger and Nigeria. In particular, the article critically investigates ...

Quality of drinking water from ponds in villages of Kolleru Lake region.

Science.gov (United States)

Rao, A S; Rao, P R; Rao, N S

2001-01-01

Kolleru Lake is the largest natural freshwater lake in the districts of East and West Godavari of Andhra Pradesh. The major population centres in the Kolleru Lake region are the 148 villages of which 50 bed villages and 98 belt villages. All bed and belt villages in lake region have at least one drinking water pond. Drinking water ponds are filled with lake water during monsoon season and directly supplied to the public throughout the year. The water samples were collected from village drinking water ponds in a year by covering three seasons and analysed for different physico-chemical parameters to assess the quality of drinking water.

Climate Change Assessments for Lakes Region of Turkey

Directory of Open Access Journals (Sweden)

Ayten Erol

2012-07-01

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

Ecosystem evolution of Lake Gusinoe (Transbaikal region, Russia)

Energy Technology Data Exchange (ETDEWEB)

Pisarsky, B.L.; Hardina, A.M.; Naganawa, H. [Russian Academy of Science, Irkutsk (Russian Federation). Siberian Division

2005-12-01

Lake Gusinoe is situated on a basin originating from Paleozoic and Mesozoic deposits. The recorded history of the lake's ecosystem evolution is no more than 300 years. The present lake drainage basin was formed mainly in the Cenozoic era, but during the past century, major anthropogenic impacts on the lake have occurred. The human-influenced evolution of the ecosystem began in the 1940s with the development of opencut coal mining nearby the lake. Population increase and the building of the Gusinoozersk State Regional Power Plant, the TransMongolian Railroad and an associated station, and military installations were the major sources of anthropogenic impacts. Since the early 1950s about five species of fish have been introduced into Lake Gusinoe or have invaded the lake, and at least six of the native species have disappeared or are in danger of extinction. From our recent investigations, the present environment of the Lake Gusinoe Basin (Gusinoozersk Basin) is divided into four zones hydro-geochemically: (1) ultrafreshwater, (2) freshwater, (3) mineralized water, and (4) hyposaline and saltwater. Some additional data on changes of the chemical components of the drainage basin waters, as well as on the transition of zooplankton and zoobenthic fauna, are presented in consideration of the risk of industrial development, and the perspectives are discussed.

Wildlife in the Upper Great Lakes Region: a community profile.

Science.gov (United States)

Janine M. Benyus; Richard R. Buech; Mark D. Nelson

1992-01-01

Wildlife habitat data from seven Great Lakes National Forests were combined into a wildlife-habitat matrix named NORTHWOODS. The composite NORTHWOODS data base is summarized. Multiple queries of NORTHWOODS were used to profile the wildlife community of the Upper Great Lakes region.

Simulation of Lake Surface Heat Fluxes by the Canadian Small Lake Model: Offline Performance Assessment for Future Coupling with a Regional Climate Model

Science.gov (United States)

Pernica, P.; Guerrero, J. L.; MacKay, M.; Wheater, H. S.

2014-12-01

Lakes strongly influence local and regional climate especially in regions where they are abundant. Development of a lake model for the purpose of integration within a regional climate model is therefore a subject of scientific interest. Of particular importance are the heat flux predictions provided by the lake model since they function as key forcings in a fully coupled atmosphere-land-lake system. The first step towards a coupled model is to validate and characterize the accuracy of the lake model over a range of conditions and to identify limitations. In this work, validation results from offline tests of the Canadian Small Lake Model; a deterministic, computationally efficient, 1D integral model, are presented. Heat fluxes (sensible and latent) and surface water temperatures simulated by the model are compared with in situ observations from two lakes; Landing Lake (NWT, Canada) and L239 (ELA, Canada) for the 2007-2009 period. Sensitivity analysis is performed to identify key parameters important for heat flux predictions. The results demonstrate the ability of the 1-D lake model to reproduce both diurnal and seasonal variations in heat fluxes and surface temperatures for the open water period. These results, in context of regional climate modelling are also discussed.

Preliminary geologic map of the Fontana 7.5' quadrangle, Riverside and San Bernardino Counties, California

Science.gov (United States)

Morton, Douglas M.; Digital preparation by Bovard, Kelly R.

2003-01-01

Open-File Report 03-418 is a digital geologic data set that maps and describes the geology of the Fontana 7.5’ quadrangle, Riverside and San Bernardino Counties, California. The Fontana quadrangle database is one of several 7.5’ quadrangle databases that are being produced by the Southern California Areal Mapping Project (SCAMP). These maps and databases are, in turn, part of the nation-wide digital geologic map coverage being developed by the National Cooperative Geologic Map Program of the U.S. Geological Survey (USGS). General Open-File Report 03-418 contains a digital geologic map database of the Fontana 7.5’ quadrangle, Riverside and San Bernardino Counties, California that includes: 1. ARC/INFO (Environmental Systems Research Institute, http://www.esri.com) version 7.2.1 coverages of the various elements of the geologic map. 2. A Postscript file (fon_map.ps) to plot the geologic map on a topographic base, and containing a Correlation of Map Units diagram (CMU), a Description of Map Units (DMU), and an index map. 3. An Encapsulated PostScript (EPS) file (fon_grey.eps) created in Adobe Illustrator 10.0 to plot the geologic map on a grey topographic base, and containing a Correlation of Map Units (CMU), a Description of Map Units (DMU), and an index map. 4. Portable Document Format (.pdf) files of: a. the Readme file; includes in Appendix I, data contained in fon_met.txt b. The same graphics as plotted in 2 and 3 above.Test plots have not produced precise 1:24,000-scale map sheets. Adobe Acrobat page size setting influences map scale. The Correlation of Map Units and Description of Map Units is in the editorial format of USGS Geologic Investigations Series (I-series) maps but has not been edited to comply with I-map standards. Within the geologic map data package, map units are identified by standard geologic map criteria such as formation-name, age, and lithology. Where known, grain size is indicated on the map by a subscripted letter or letters following

Ecological risk of methylmercury to piscivorous fish of the Great Lakes region.

Science.gov (United States)

Sandheinrich, Mark B; Bhavsar, Satyendra P; Bodaly, R A; Drevnick, Paul E; Paul, Eric A

2011-10-01

Contamination of fish populations with methylmercury is common in the region of the Laurentian Great Lakes as a result of atmospheric deposition and methylation of inorganic mercury. Using fish mercury monitoring data from natural resource agencies and information on tissue concentrations injurious to fish, we conducted a screening-level risk assessment of mercury to sexually mature female walleye (Sander vitreus), northern pike (Esox lucius), smallmouth bass (Micropterus dolomieu), and largemouth bass (Micropterus salmoides) in the Great Lakes and in interior lakes, impoundments, and rivers of the Great Lakes region. The assessment included more than 43,000 measurements of mercury in fish from more than 2000 locations. Sexually mature female fish that exceeded threshold-effect tissue concentrations of 0.20 μg g(-1) wet weight in the whole body occurred at 8% (largemouth bass) to 43% (walleye) of sites. Fish at 3% to 18% of sites were at risk of injury and exceeded 0.30 μg g(-1) where an alteration in reproduction or survival is predicted to occur. Most fish at increased risk were from interior lakes and impoundments. In the Great Lakes, no sites had sexually mature fish that exceeded threshold-effect concentrations. Results of this screening-level assessment indicate that fish at a substantive number of locations within the Great Lakes region are potentially at risk from methylmercury contamination and would benefit from reduction in mercury concentrations.

Reaching Regional and Local Learners via a Great Lakes MOOC

Science.gov (United States)

Mooney, M. E.; Ackerman, S. A.

2015-12-01

The Cooperative Institute of Meteorological Satellite Studies (CIMSS) took a regional approach to climate change education in a 4-week MOOC (Massive Open On-line Course) on the Changing Weather and Climate in the Great Lakes Region launched in February 2015. Featuring a different season each week, this Great Lakes MOOC includes lectures about seasonal weather conditions, observed changes, and societal impacts of regional climate change, as well as actions with co-benefits to slow future climate change. To better connect with learners, CIMSS facilitated 21 discussion groups at public libraries around Wisconsin each week. Participants discussed climate change impacts in their communities as well as strategies to mitigate climate change. Not surprisingly, initial survey results show library participants were more committed, engaged, climate literate, and community minded. This session will share lessons learned and survey results from the Great Lakes MOOC which remains open and accessible on Coursera through February 2016 at https://www.coursera.org/course/greatlakesclimate.

Challenges in Developing Ecotourism in The Region of Lake Sentani Papua

Directory of Open Access Journals (Sweden)

Yannice Luma Marnala Sitorus

2017-03-01

Full Text Available The concept of community-based ecotourism is one of the sustainable development concepts suitable to be applied to traditional regions with nature tourism potential. Differences in culture between traditional communities and the outside world are not an obstacle in developing the region because with their local wisdom traditional communities can participate in protecting and managing their natural surrounding and at the same time become an attraction for other communities. However, outside societies can influence the culture of the traditional communities that originally tends to be oriented on biocentrism to shift towards anthropocentrism. This can eventually hamper the continuity of ecotourism development. This can be seen from the traditional communities at Lake Sentani, the case study of the author. The study is based on literature and secondary data and used descriptive analysis. The traditional communities of Sentani do not yet fully participate in the development of tourism in its surroundings. Their involvement in tourism development is more focused on ceremonial activities such as can be seen at the Lake Sentani Festival which is organized every year by the government. Besides this, after coming into contact with modern life the traditional communities of Lake Sentani rarely perform their daily activities based on local wisdom aimed at natural conservation of the lake. The development of urban areas in the surroundings also influences changes in land use in the Lake Sentani region which then causes among others erosion, sedimentation, and pollution of the lake water. Socio-economic and cultural changes in the traditional communities of Sentani and the growth of development also contribute towards ecological change in the area of Lake Sentani, the place they live in.

The Oligochaeta (Annelida, Clitellata) of the St. Lawrence Great Lakes region: An update

Science.gov (United States)

Spencer, Douglas R.; Hudson, Patrick L.

2003-01-01

An updated oligochaete species list for the Great Lakes region is provided. The list was developed through the reexamination of the taxa reported in a previous report in 1980, addition of new taxa or records collected from the region since 1980, and an update of taxonomy commensurate with systematic and nomenclatural changes over the intervening years since the last review. The authors found 74 papers mentioning Great Lakes oligochaete species. The majority of these papers were published in the 1980s. The literature review and additional collections resulted in 15 species being added to the previous list. Nine taxa were removed from the previous list due to misidentification, synonymies, level of identification, or inability to confirm the identity. Based on this review, 101 species of Oligochaeta are now known from the St. Lawrence Great Lakes watershed. Of these, 95 species are known from the St. Lawrence Great Lakes proper, with an additional 6 species recorded from the inland waters of the watershed. The greatest diversity of oligochaete species was found in the inland waters of the region (81) followed by Lake Huron (72), Lake Ontario (65), Lake Erie (64), Lake Superior (63), Lake Michigan (62), St. Marys River (60), Niagara River (49), Saginaw Bay (44), St. Clair River (37), Lake St. Clair (36), St. Lawrence River (27), and the Detroit River (21). Three species are suspected of being introduced, Branchiura sowerbyi, Gianius aquaedulcisand Ripistes parasita, and two are believed to be endemic, Thalassodrilus hallae andTeneridrilus flexus.

A SIMULATION STUDY ON THE SHRUNK WETLAND AROUND QINGHAI LAKE AND REGIONAL CLIMATE

Institute of Scientific and Technical Information of China (English)

WANG HanJie; JING Li; GAO YunXiao

2005-01-01

Because of the increasing concerns about global climate change, it has been known by more and more peoples that there is a close relationship between wetland and/or peatland resources and climate change. This paper presents a new methodology to study the local climate variation caused by wetland shrinking around Qinghai Lake, the largest in-land salty lake in China, by use of a regional climate model (RCM) that commonly used in climate change study. The objective focuses on the regional climate effect of the shrunk wetland coverage in recent years. The results of numerical experiment showed that if the wetland coverage around Qinhai Lake were recovered as if in early 50s of last century,the regional climate in this area could be better with more cloud covers, higher relative humidity and more precipitation. In the other word, the area of wetland reduced is one of the most important reasons that caused regional climate aridification,eco-environmental deterioration and even desertification around Qinhai Lake.

Effects of land use on lake nutrients: The importance of scale, hydrologic connectivity, and region

Science.gov (United States)

Soranno, Patricia A.; Cheruvelil, Kendra Spence; Wagner, Tyler; Webster, Katherine E.; Bremigan, Mary Tate

2015-01-01

Catchment land uses, particularly agriculture and urban uses, have long been recognized as major drivers of nutrient concentrations in surface waters. However, few simple models have been developed that relate the amount of catchment land use to downstream freshwater nutrients. Nor are existing models applicable to large numbers of freshwaters across broad spatial extents such as regions or continents. This research aims to increase model performance by exploring three factors that affect the relationship between land use and downstream nutrients in freshwater: the spatial extent for measuring land use, hydrologic connectivity, and the regional differences in both the amount of nutrients and effects of land use on them. We quantified the effects of these three factors that relate land use to lake total phosphorus (TP) and total nitrogen (TN) in 346 north temperate lakes in 7 regions in Michigan, USA. We used a linear mixed modeling framework to examine the importance of spatial extent, lake hydrologic class, and region on models with individual lake nutrients as the response variable, and individual land use types as the predictor variables. Our modeling approach was chosen to avoid problems of multi-collinearity among predictor variables and a lack of independence of lakes within regions, both of which are common problems in broad-scale analyses of freshwaters. We found that all three factors influence land use-lake nutrient relationships. The strongest evidence was for the effect of lake hydrologic connectivity, followed by region, and finally, the spatial extent of land use measurements. Incorporating these three factors into relatively simple models of land use effects on lake nutrients should help to improve predictions and understanding of land use-lake nutrient interactions at broad scales.

Regional pattern of snow characteristics around Antarctic Lake Vostok

Science.gov (United States)

Vladimirova, Diana; Ekaykin, Alexey; Popov, Sergey; Shibaev, Yuriy; Kozachek, Anna; Lipenkov, Vladimir

2015-04-01

Since 1998 Russian Antarctic Expedition has organized several scientific traverses in the region of subglacial Lake Vostok mainly devoted to the radar echo and seismic sounding of the glacier and water (the results have been published elsewhere). Along with the geophysical studies, a number of glaciological investigations have been carried out: snow pit digging, installation of accumulation stakes, snow sampling to study the stable water isotope content. Here we for the first time present a synthesis of these works and demonstrate a series of maps that characterize the snow density, isotope content and accumulation rate the studied region. A general tendency of the snow accumulation rate and isotope content is a significant increase from south (south-west) to north (north-east) from 35 to 23 mm w.e. per year and from -53,3 ‰ to -57,3 ‰ for delta oxygen-18 respectively, which likely reflects the continental-scale pattern, i.e., increase from inland to the coast. Deuterium excess varies from 11,7 ‰ to 16,3 ‰ is negatively correlated with the isotope content, which is typical for central Antarctica. The snow density demonstrate different pattern: higher values offshore the lake (up to 0,356 g/cm^3), and lower values within the lake's shoreline (lower limit is 0,328 g/cm^3). We suggest that this is related to the katabatic wind activity: very flat nearly horizontal surface of the glacier above the lake is not favorable for the strong winds, which leads to lower surface snow density. Superimposed on the main trend is the regional pattern, namely, curved contour lines in the middle part of the lake. We suggest that it may be related to the local anomalies of the snow drift by wind. Indeed, on the satellite images of the lake one can easily see a snowdrift stretching from the lake's western shore downwind in the middle part of the lake. The isolines of delta oxygen-18 and deuterium excess become perpendicular to each other in the north part of the lake which also

PeRL: a circum-Arctic Permafrost Region Pond and Lake database

Science.gov (United States)

Muster, Sina; Roth, Kurt; Langer, Moritz; Lange, Stephan; Cresto Aleina, Fabio; Bartsch, Annett; Morgenstern, Anne; Grosse, Guido; Jones, Benjamin; Sannel, A. Britta K.; Sjöberg, Ylva; Günther, Frank; Andresen, Christian; Veremeeva, Alexandra; Lindgren, Prajna R.; Bouchard, Frédéric; Lara, Mark J.; Fortier, Daniel; Charbonneau, Simon; Virtanen, Tarmo A.; Hugelius, Gustaf; Palmtag, Juri; Siewert, Matthias B.; Riley, William J.; Koven, Charles D.; Boike, Julia

2017-06-01

Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost Region Pond and Lake (PeRL) database presents the results of a circum-Arctic effort to map ponds and lakes from modern (2002-2013) high-resolution aerial and satellite imagery with a resolution of 5 m or better. The database also includes historical imagery from 1948 to 1965 with a resolution of 6 m or better. PeRL includes 69 maps covering a wide range of environmental conditions from tundra to boreal regions and from continuous to discontinuous permafrost zones. Waterbody maps are linked to regional permafrost landscape maps which provide information on permafrost extent, ground ice volume, geology, and lithology. This paper describes waterbody classification and accuracy, and presents statistics of waterbody distribution for each site. Maps of permafrost landscapes in Alaska, Canada, and Russia are used to extrapolate waterbody statistics from the site level to regional landscape units. PeRL presents pond and lake estimates for a total area of 1. 4 × 106 km2 across the Arctic, about 17 % of the Arctic lowland ( pangaea.de/10.1594/PANGAEA.868349" target="_blank">https://doi.pangaea.de/10.1594/PANGAEA.868349.

[Ecological compensation standard in Dongting Lake region of returning cropland to lake based on emergy analysis].

Science.gov (United States)

Mao, De-Hua; Hu, Guang-Wei; Liu, Hui-Jie; Li, Zheng-Zui; Li, Zhi-Long; Tan, Zi-Fang

2014-02-01

The annual emergy and currency value of the main ecological service value of returning cropland to lake in Dongting Lake region from 1999 to 2010 was calculated based on emergy analysis. The calculation method of ecological compensation standard was established by calculating annual total emergy of ecological service function increment since the starting year of returning cropland to lake, and the annual ecological compensation standard and compensation area were analyzed from 1999 to 2010. The results indicated that ecological compensation standard from 1999 to 2010 was 40.31-86.48 yuan x m(-2) with the mean of 57.33 yuan x m(-2). The ecological compensation standard presented an increase trend year by year due to the effect of eco-recovery of returning cropland to lake. The ecological compensation standard in the research area presented a swift and steady growth trend after 2005 mainly due to the intensive economy development of Hunan Province, suggesting the value of natural ecological resources would increase along with the development of society and economy. Appling the emergy analysis to research the ecological compensation standard could reveal the dynamics of annual ecological compensation standard, solve the abutment problem of matter flow, energy flow and economic flow, and overcome the subjective and arbitrary of environment economic methods. The empirical research of ecological compensation standard in Dongting Lake region showed that the emergy analysis was feasible and advanced.

Hydrogeochemical evaluation of conventional and hot dry rock geothermal resource potential in the Clear Lake region, California

Energy Technology Data Exchange (ETDEWEB)

Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.

1993-05-01

Chemistry, stable isotope, and tritium contents of thermal/mineral waters in the Clear Lake region were used to evaluate conventional and hot dry rock (HDR) geothermal potential for electrical generation. Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connate types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connate (generic) end-members. The latter end-member has enriched {delta}D as well as enriched {delta}{sup 18}O, from typical high-temperature geothermal reservoir waters. Tritium data indicate most Clear Lake region waters are mixtures of old and young fluid components. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is {le}150{degree}C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures {le}150{degree}C (except for Sulphur Bank mine). HDR technologies are probably the best way to commercially exploit the known high-temperatures existing beneath the Clear Lake region particularly within and near the main Clear Lake volcanic field.

Lake nutrient stoichiometry is less predictable than nutrient concentrations at regional and sub-continental scales.

Science.gov (United States)

Collins, Sarah M; Oliver, Samantha K; Lapierre, Jean-Francois; Stanley, Emily H; Jones, John R; Wagner, Tyler; Soranno, Patricia A

2017-07-01

Production in many ecosystems is co-limited by multiple elements. While a known suite of drivers associated with nutrient sources, nutrient transport, and internal processing controls concentrations of phosphorus (P) and nitrogen (N) in lakes, much less is known about whether the drivers of single nutrient concentrations can also explain spatial or temporal variation in lake N:P stoichiometry. Predicting stoichiometry might be more complex than predicting concentrations of individual elements because some drivers have similar relationships with N and P, leading to a weak relationship with their ratio. Further, the dominant controls on elemental concentrations likely vary across regions, resulting in context dependent relationships between drivers, lake nutrients and their ratios. Here, we examine whether known drivers of N and P concentrations can explain variation in N:P stoichiometry, and whether explaining variation in stoichiometry differs across regions. We examined drivers of N:P in ~2,700 lakes at a sub-continental scale and two large regions nested within the sub-continental study area that have contrasting ecological context, including differences in the dominant type of land cover (agriculture vs. forest). At the sub-continental scale, lake nutrient concentrations were correlated with nutrient loading and lake internal processing, but stoichiometry was only weakly correlated to drivers of lake nutrients. At the regional scale, drivers that explained variation in nutrients and stoichiometry differed between regions. In the Midwestern U.S. region, dominated by agricultural land use, lake depth and the percentage of row crop agriculture were strong predictors of stoichiometry because only phosphorus was related to lake depth and only nitrogen was related to the percentage of row crop agriculture. In contrast, all drivers were related to N and P in similar ways in the Northeastern U.S. region, leading to weak relationships between drivers and stoichiometry

Regional groundwater-flow model of the Lake Michigan Basin in support of Great Lakes Basin water availability and use studies

Science.gov (United States)

Feinstein, D.T.; Hunt, R.J.; Reeves, H.W.

2010-01-01

A regional groundwater-flow model of the Lake Michigan Basin and surrounding areas has been developed in support of the Great Lakes Basin Pilot project under the U.S. Geological Survey's National Water Availability and Use Program. The transient 2-million-cell model incorporates multiple aquifers and pumping centers that create water-level drawdown that extends into deep saline waters. The 20-layer model simulates the exchange between a dense surface-water network and heterogeneous glacial deposits overlying stratified bedrock of the Wisconsin/Kankakee Arches and Michigan Basin in the Lower and Upper Peninsulas of Michigan; eastern Wisconsin; northern Indiana; and northeastern Illinois. The model is used to quantify changes in the groundwater system in response to pumping and variations in recharge from 1864 to 2005. Model results quantify the sources of water to major pumping centers, illustrate the dynamics of the groundwater system, and yield measures of water availability useful for water-resources management in the region. This report is a complete description of the methods and datasets used to develop the regional model, the underlying conceptual model, and model inputs, including specified values of material properties and the assignment of external and internal boundary conditions. The report also documents the application of the SEAWAT-2000 program for variable-density flow; it details the approach, advanced methods, and results associated with calibration through nonlinear regression using the PEST program; presents the water-level, drawdown, and groundwater flows for various geographic subregions and aquifer systems; and provides analyses of the effects of pumping from shallow and deep wells on sources of water to wells, the migration of groundwater divides, and direct and indirect groundwater discharge to Lake Michigan. The report considers the role of unconfined conditions at the regional scale as well as the influence of salinity on groundwater flow

Evidence for regional nitrogen stress on chlorophyll a in lakes across large landscape and climate gradients

Science.gov (United States)

Filstrup, Christopher T.; Wagner, Tyler; Oliver, Samantha K.; Stow, Craig A.; Webster, Katherine E.; Stanley, Emily H.; Downing, John A.

2018-01-01

Nitrogen (N) and phosphorus (P) commonly stimulate phytoplankton production in lakes, but recent observations from lakes from an agricultural region suggest that nitrate may have a subsidy‐stress effect on chlorophyll a (Chl a). It is unclear, however, how generalizable this effect might be. Here, we analyzed a large water quality dataset of 2385 lakes spanning 60 regions across 17 states in the Northeastern and Midwestern U.S. to determine if N subsidy‐stress effects on phytoplankton are common and to identify regional landscape characteristics promoting N stress effects in lakes. We used a Bayesian hierarchical modeling framework to test our hypothesis that Chl a–total N (TN) threshold relationships would be common across the central agricultural region of the U.S. (“the Corn Belt”), where lake N and P concentrations are high. Data aggregated across all regions indicated that high TN concentrations had a negative effect on Chl a in lakes with concurrent high total P. This large‐scale pattern was driven by relationships within only a subset of regions, however. Eight regions were identified as having Chl a–TN threshold relationships, but only two of these regions located within the Corn Belt clearly demonstrated this subsidy‐stress relationship. N stress effects were not consistent across other intense agricultural regions, as we hypothesized. These findings suggest that interactions among regional land use and land cover, climate, and hydrogeology may be important in determining the synergistic conditions leading to N subsidy‐stress effects on lake phytoplankton.

Great Lakes Regional Biomass Energy Program

International Nuclear Information System (INIS)

Kuzel, F.

1993-01-01

The Great Lakes Regional Biomass Energy Program (GLRBEP) was initiated September, 1983, with a grant from the Office of Energy Efficiency and Renewable Energy of the US Department of Energy (DOE). The program provides resources to public and private organizations in the Great Lakes region to increase the utilization and production of biomass fuels. The objectives of the GLRBEP are to: (1) improve the capabilities and effectiveness of biomass energy programs in the state energy offices; (2) assess the availability of biomass resources for energy in light of other competing needs and uses; (3) encourage private sector investments in biomass energy technologies; (4) transfer the results of government-sponsored biomass research and development to the private sector; (5) eliminate or reduce barriers to private sector use of biomass fuels and technology; (6) prevent or substantially mitigate adverse environmental impacts of biomass energy use. The Program Director is responsible for the day-to-day activities of the GLRBEP and for implementing program mandates. A 40 member Technical Advisory Committee (TAC) sets priorities and recommends projects. The governor of each state in the region appoints a member to the Steering Council, which acts on recommendations of the TAC and sets basic program guidelines. The GLRBEP is divided into three separate operational elements. The State Grants component provides funds and direction to the seven state energy offices in the region to increase their capabilities in biomass energy. State-specific activities and interagency programs are emphasized. The Subcontractor component involves the issuance of solicitations to undertake projects that address regional needs, identified by the Technical Advisory Committee. The Technology Transfer component includes the development of nontechnical biomass energy publications and reports by Council staff and contractors, and the dissemination of information at conferences, workshops and other events

Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

Data.gov (United States)

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...

Understanding Obstacles to Peace in the Great Lakes Region ...

International Development Research Centre (IDRC) Digital Library (Canada)

Africa's Great Lakes region is home to violent and prolonged conflicts that cause a lot of suffering and block socioeconomic progress. Several initiatives are underway to bring peace to the region. But, most of these focus on specific countries and have not taken into account the interrelated and overlapping nature of the ...

How much acidification has occurred in Adirondack region lakes (New York, USA) since preindustrial times

International Nuclear Information System (INIS)

Cumming, B.F.; Smol, J.P.; Kingston, J.C.; Charles, D.F.; Birks, H.J.B.

1992-01-01

Preindustrial and present-day lake water pH, acid neutralizing capacity (ANC), total monomeric aluminum Al(sub m), and dissolved organic carbon (DOC) were inferred from the species composition of diatom and chrysophyte microfossils in the tops (present-day inferences) and bottoms (pre-1850 inferences) of sediment cores collected from a statistically selected set of Adirondack lakes. Results from the study lakes were extrapolated to a predefined target population of 675 low-alkalinity Adirondack region lakes. Estimates of preindustrial to present-day changes in lake water chemistry show that approximately 25-35% of the target population has acidified. The magnitude of acidification was greatest in the low-alkalinity lakes of the southwestern Adirondacks, an area with little geological ability to neutralize acidic deposition and receives the highest annual average rainfall in the region. The authors estimate that approximately 80% of the target population lakes with present-day measured pH = or < 5.2 and 30-45% of lakes with pH between 5.2 and 6.0 have undergone large declines in pH and ANC, and concomitant increases in Al(sub m). Estimated changes in (DOC) were small and show no consistent pattern in the acidified lakes. The study provides the first statistically based regional evaluation of the extent of lake acidification in the Adirondacks

Heavy metals in bottom sediments of Lake Umbozero in Murmansk Region, Russia

DEFF Research Database (Denmark)

Jernström, Jussi; Lehto, J.; Dauvalter, A.

2010-01-01

Sediment cores collected from different locations of Lake Umbozero were studied with respect to concentration and mobility of trace and heavy metals Co, Cu, Fe, Mn, Ni, Pb, U, and Zn. Lake Umbozero is the second largest lake in the Murmansk Region and subjected to contamination by air......-borne emissions and river transportation from the nearby metallurgical and mining industries. Unlike its neighboring, more industry-prone Lake Imandra, Lake Umbozero is relatively unexplored with respect to its state of pollution. In our study, metal distribution in sediments was found to vary with respect...... in lakes of Kola Peninsula located further off from industrial pollutant sources. An exception was Pb the concentration of which was at the same level as in Lake Imandra, probably due to long-distance transport. Sediment layers were subjected to four-step sequential extraction procedure to reveal the metal...

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

Directory of Open Access Journals (Sweden)

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.

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

Science.gov (United States)

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.

INTEGRATED DIGITAL SURVEY OF THE "FONTANA RUSTICA" IN THE GARDENS OF THE QUIRINALE.

Directory of Open Access Journals (Sweden)

L. Paris

2013-07-01

Full Text Available The paper illustrates the results of a research on integrated digital survey of the "Fontana Rustica" in the gardens of the Quirinale, artifact somewhat atypical for its particular organical configuration, and whose history is still to be discovered. The activity is performed by Critevat, interdepartmental research center in Rieti, within of the scientific collaboration with the Office for the conservation of artistic heritage of the Quirinale Palace. The integrated digital survey in recent years has had a strong impulse thanks to the technological development of the shape acquisition instruments. The research has analyzed the problems of interaction and integration of digital data obtainable using the latest digital technologies such as 3D laser-scanner and digital photogrammetry. A further level of research has focused on the possibility of management of 3D models in relation to data obtained by instruments and methods of investigation of different scientific culture such as seismic transmission tomography and thermografy.

Integrated Digital Survey of the "FONTANA RUSTICA" in the Gardens of the Quirinale.

Science.gov (United States)

Paris, L.; Troiano, W.

2013-07-01

The paper illustrates the results of a research on integrated digital survey of the "Fontana Rustica" in the gardens of the Quirinale, artifact somewhat atypical for its particular organical configuration, and whose history is still to be discovered. The activity is performed by Critevat, interdepartmental research center in Rieti, within of the scientific collaboration with the Office for the conservation of artistic heritage of the Quirinale Palace. The integrated digital survey in recent years has had a strong impulse thanks to the technological development of the shape acquisition instruments. The research has analyzed the problems of interaction and integration of digital data obtainable using the latest digital technologies such as 3D laser-scanner and digital photogrammetry. A further level of research has focused on the possibility of management of 3D models in relation to data obtained by instruments and methods of investigation of different scientific culture such as seismic transmission tomography and thermografy.

Hydroclimatic variability in the Lake Mondsee region and its relationships with large-scale climate anomaly patterns

Science.gov (United States)

Rimbu, Norel; Ionita, Monica; Swierczynski, Tina; Brauer, Achim; Kämpf, Lucas; Czymzik, Markus

2017-04-01

Flood triggered detrital layers in varved sediments of Lake Mondsee, located at the northern fringe of the European Alps (47°48'N,13°23'E), provide an important archive of regional hydroclimatic variability during the mid- to late Holocene. To improve the interpretation of the flood layer record in terms of large-scale climate variability, we investigate the relationships between observational hydrological records from the region, like the Mondsee lake level, the runoff of the lake's main inflow Griesler Ache, with observed precipitation and global climate patterns. The lake level shows a strong positive linear trend during the observational period in all seasons. Additionally, lake level presents important interannual to multidecadal variations. These variations are associated with distinct seasonal atmospheric circulation patterns. A pronounced anomalous anticyclonic center over the Iberian Peninsula is associated with high lake levels values during winter. This center moves southwestward during spring, summer and autumn. In the same time, a cyclonic anomaly center is recorded over central and western Europe. This anomalous circulation extends southwestward from winter to autumn. Similar atmospheric circulation patterns are associated with river runoff and precipitation variability from the region. High lake levels are associated with positive local precipitation anomalies in all seasons as well as with negative local temperature anomalies during spring, summer and autumn. A correlation analysis reveals that lake level, runoff and precipitation variability is related to large-scale sea surface temperature anomaly patterns in all seasons suggesting a possible impact of large-scale climatic modes, like the North Atlantic Oscillation and Atlantic Multidecadal Oscillation on hydroclimatic variability in the Lake Mondsee region. The results presented in this study can be used for a more robust interpretation of the long flood layer record from Lake Mondsee sediments

Evaluation of regional climate simulations over the Great Lakes region driven by three global data sets

Science.gov (United States)

Shiyuan Zhong; Xiuping Li; Xindi Bian; Warren E. Heilman; L. Ruby Leung; William I. Jr. Gustafson

2012-01-01

The performance of regional climate simulations is evaluated for the Great Lakes region. Three 10-year (1990-1999) current-climate simulations are performed using the MM5 regional climate model (RCM) with 36-km horizontal resolution. The simulations employed identical configuration and physical parameterizations, but different lateral boundary conditions and sea-...

Monitoring lake level changes by altimetry in the arid region of Central Asia

Science.gov (United States)

Zhao, Y.; Liao, J. J.; Shen, G. Z.; Zhang, X. L.

2017-07-01

The study of lake level changes in arid region of Central Asia not only has important significance for the management and sustainable development of inland water resources, but also provides the basis for further study on the response of lakes to climate change and human activities. Therefore, in this paper, eleven typical lakes in Central Asia were observed. The lake edges were obtained through image interpretation using the quasi-synchronous MODIS image, and then water level information with long period (2002-2015) was acquired using ENVISAT/RA-2 and Cryosat-2 satellite borne radar altimeter data. The results show that these 11 lakes all have obvious seasonal changes of water level in a year with a high peak at different month. During 2002 - 2015, their water levels present decreased trend generally except Sarygamysh Lake, Alakol Lake and North Aral Sea. The alpine lakes are most stables, while open lakes’ levels change the most violently and closed lakes change diversely among different lakes.

Paleogeography of the Austro-Hungarian Lake Neusiedl - Hansag region in historic times, based on 14C-dating

International Nuclear Information System (INIS)

Haeusler, H.; Sauermann, I.; Kovacs, G.; Wild, E.; Steiner, P.

2007-01-01

Full text: Based on calibrated 14 C-dating of several peat sections intercalating with fine-grained beds in the Hansag southeast of Lake Neusiedl we present a first approach of the paleogeography of the Austro-Hungarian border region during a time span when first settlements already existed and before the first detailed topographic maps of this region were drawn. About one hundred pits down to one metre were digged out in the Hansag region near Osli in 2003 for studying the recultivation of this regularly flooded area in an environmental geo-information system (GIS). Several sections clearly show an alternation of peat layers intersected by fine-grained fluvio-lacustrine sediments. 15 age determinations of samples from several sections underlying and overlying silty to clayey sediments allow for reconstructing the succession of longer stillwater deposits alternating with peat successions. Comparing the Hansag succession with historic records of the vicinity of Lake Neusiedl allows for a new insight in this unique development of the Lake Neusiedl - Hansag region, at present situated within the Austro-Hungarian national park. It should be recalled, that Lake Neusiedl is Central Europe's largest step lake and Austria's youngest UNESCO World Cultural Heritage site. The paleo-environment of the Lake Neusiedl - Hansag region basically can be designed in four steps by comparing the archaeological findings around Lake Neusiedl with our 14 C-dating of peat layers in the Hansag region: 1: the oldest settlements in the Lake Neusiedl region date about 3600 BC, and 1700 BC respectively. During this periods the lake probably was quite smaller than today. Our 14 C-dating of peat sections in the Hansag region corresponds with these findings, indicating that during a time span of approximately 2000 years until 30 Anno Domini (AD) no bigger lake existed in the Neusiedl- Hansag region. Small pieces of charcoal dating around 2300 BC can have been caused by bush fire and therefore be

Lake seasonality across the Tibetan Plateau and their varying relationship with regional mass changes and local hydrology

Science.gov (United States)

Lei, Yanbin; Yao, Tandong; Yang, Kun; Sheng, Yongwei; Kleinherenbrink, Marcel; Yi, Shuang; Bird, Broxton W.; Zhang, Xiaowen; Zhu, La; Zhang, Guoqing

2017-01-01

The recent growth and deepening of inland lakes in the Tibetan Plateau (TP) may be a salient indicator of the consequences of climate change. The seasonal dynamics of these lakes is poorly understood despite this being potentially crucial for disentangling contributions from glacier melt and precipitation, which are all sensitive to climate, to lake water budget. Using in situ observations, satellite altimetry and gravimetry data, we identified two patterns of lake level seasonality. In the central, northern, and northeastern TP, lake levels are characterized by considerable increases during warm seasons and decreases during cold seasons, which is consistent with regional mass changes related to monsoon precipitation and evaporation. In the northwestern TP, however, lake levels exhibit dramatic increases during both warm and cold seasons, which deviate from regional mass changes. This appears to be more connected with high spring snowfall and large summer glacier melt. The variable lake level response to different drivers indicates heterogeneous sensitivity to climate change between the northwestern TP and other regions.

ASTER measurement of supraglacial lakes in the Mount Everest region of the Himalaya

Science.gov (United States)

Wessels, R.L.; Kargel, J.S.; Kieffer, H.H.

2002-01-01

We demonstrate an application of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images to detect and monitor supraglacial lakes on glaciers in the Mount Everest region in Tibet (Xizang) and Nepal. ASTER offers powerful capabilities to monitor supraglacial lakes in terms of (1) surface area, growth and disappearance (spatial resolution = 15 m), (2) turbidity (15 m resolution), and (3) temperature (90 m resolution). Preliminary results show an overall similarity of supraglacial lakes on three glaciers. Lakes have widely varying turbidity as indicated by color in visible/near-infrared bands 1-3, the largest lakes being bright blue (highly turbid), cold (near 0??C) and hydrautically connected with other lakes and supraglacial streams, while small lakes are mostly dark blue (relatively clear water), warmer (>4??C), and appear hydrautically isolated. High levels of turbidity in supraglacial lakes indicate high rates of meltwater input from streams or erosion of ice cliffs, and thus are an indirect measure relating to the activity and hydraulic integration of the lake with respect to other lakes and streams in the glacier.

Sunshine-based estimation of global solar radiation on horizontal surface at Lake Van region (Turkey)

International Nuclear Information System (INIS)

Duzen, Hacer; Aydin, Harun

2012-01-01

Highlights: ► The global solar radiation at Lake Van region is estimated. ► This study is unique for the Lake Van region. ► Solar radiation around Lake Van has the highest value at the east-southeast region. ► The annual average solar energy potential is obtained as 750–2458 kWh/m 2 . ► Results can be used to estimate evaporation. - Abstract: In this study several sunshine-based regression models have been evaluated to estimate monthly average daily global solar radiation on horizontal surface of Lake Van region in the Eastern Anatolia region in Turkey by using data obtained from seven different meteorological stations. These models are derived from Angström–Prescott linear regression model and its derivatives such as quadratic, cubic, logarithmic and exponential. The performance of this regression models were evaluated by comparing the calculated clearness index and the measured clearness index. Several statistical tests were used to control the validation and goodness of the regression models in terms of the coefficient of determination, mean percent error, mean absolute percent error, mean biased error, mean absolute biased error, root mean square error and t-statistic. The results of all the regression models are within acceptable limits according to the statistical tests. However, the best performances are obtained by cubic regression model for Bitlis, Gevaş, Hakkari, Muş stations and by quadratic regression model for Malazgirt, Tatvan and Van stations to predict global solar radiation. The spatial distributions of the monthly average daily global solar radiation around the Lake Van region were obtained with interpolation of calculated solar radiation data that acquired from best fit models of the stations. The annual average solar energy potential for Lake Van region is obtained between 750 kWh/m 2 and 2485 kWh/m 2 with annual average of 1610 kWh/m 2 .

Land use impacts on lake water quality in Alytus region (Lithuania)

Science.gov (United States)

Pereira, Paulo; Laukonis, Rymvidas

2016-04-01

Land use has important impacts on soils, surface and ground water quality. Urban agricultural areas are an important source of pollutants, which can reach lakes through surface runoff and underground circulation. Human intervention in the landscape is one of the major causes pollution and land degradation, thus it is very important to understand the impacts of and use on environment and if they have some spatial pattern (Pereira et al., 2013, 2015; Brevik et al., 2016). The identification of the spatial pattern of lakes pollution is in Alytus area (Lithuania) is fundamental, since they provide an important range of ecosystem services to local communities, including food and recreational activities. Thus, the degradation of these environments can induce important economic losses. In this context, it is import to identify the areas with high pollutant accumulation and the environmental and human factors responsible for it. The objective of this work is to study identify the amount of some important nutrients resultant from human activities in lake water quality in Alytus region (Lithuania). Alytus region is located in southern part of Lithuania and has an approximate area of 40 km2. Inside this region we analyzed several water quality parameters of 55 lakes, including, pH, electrical conductivity (EC), suspended materials (SM), water clarity (WC) biochemical oxygen demand (BDO), total phosphorous (TP), total Nitrogen (TN), dissolved organic carbon (DOC), as other environmental variables as altitude, lake maximum deep (MD), lake area and land use according Corine land cover classification (CLC2006). Previous to data analysis, data normality and homogeneity of the variances, was assessed with the Shapiro-wilk and Leven's test, respectively. The majority of the data did not respect the Gaussian distribution and the heteroscedasticity, even after a logarithmic, and box-cox transformation. Thus, in this work we used the logarithmic transformed data to do a principal

Water resources of the Lake Erie shore region in Pennsylvania

Science.gov (United States)

Mangan, John William; Van Tuyl, Donald W.; White, Walter F.

1952-01-01

An abundant supply of water is available to the Lake Erie Shore region in Pennsylvania. Lake i£rie furnishes an almost inexhaustible supply of water of satisfactory chemical quality. Small quantities of water are available from small streams in the area and from the ground. A satisfactory water supply is one of the factors that affect the economic growth of a region. Cities and towns must have adequate amounts of pure water for human consumption. Industries must have suitable water ih sufficient quantities for all purposes. In order to assure. success and economy, the development of water resources should be based on adequate knowledge of the quantity and quality of the water. As a nation, we can not afford to run the risk of dissipating our resources, especially in times of national emergency, by building projects that are not founded on sound engineering and adequate water-resources information. The purpose of this report is to summarize and interpret all available water-resources information for the Lake Erie Shore region in Pennsylvania. The report will be useful for initial guidance in the location or expansion of water facilities for defense and nondefense industries and the municipalities upon which they are dependent. It will also be useful in evaluating the adequacy of the Geological Survey's part of the basic research necessary to plan the orderly development of the water resources of the Lake Erie Shore region. Most of the data contained inthis report have been obtained'by the U. S. Geological Survey in cooperation with the Pennsylvania Department of Forests and Waters, the Pennsylvania Department of Internal Affairs, and the Pennsylvania State Planning Board, Department of Commerce. The Pennsylv~nia Department of Health furnished information on water pollution. The report was prepared in the Water Resources Division of the U. S. Geological Survey b:y John W. Mangan (Surface Water). Donald W. VanTuyl (Ground Water). and Walter F. White, Jr. (Quality of

Geochemistry of thermal/mineral waters in the Clear Lake region, California, and implications for hot dry rock geothermal development

Energy Technology Data Exchange (ETDEWEB)

Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.; Mansfield, J.

1993-02-01

Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connote types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast, ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connote end-members. The latter end-member has enriched [delta]D as well as enriched d[sup l8]O, very different from typical high-temperature geothermal reservoir waters. Tritium data and modeling of ages indicate most Clear Lake region waters are 500 to > 10,000 yr., although mixing of old and young components is implied by the data. The age of end-member connate water is probably > 10,000 yr. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is [le] 150[degrees]C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures [le] 150[degrees]C (except for Sulphur Bank Mine). Hot dry rock technologies are the best way to commercially exploit the known high temperatures existing beneath the Clear Lake region, particularly within the main Clear Lake volcanic field.

Regional Analysis of the Hazard Level of Glacial Lakes in the Cordillera Blanca, Peru

Science.gov (United States)

Chisolm, Rachel E.; Jhon Sanchez Leon, Walter; McKinney, Daene C.; Cochachin Rapre, Alejo

2016-04-01

The Cordillera Blanca mountain range is the highest in Peru and contains many of the world's tropical glaciers. This region is severely impacted by climate change causing accelerated glacier retreat. Secondary impacts of climate change on glacier retreat include stress on water resources and the risk of glacial lake outburst floods (GLOFs) from the many lakes that are forming and growing at the base of glaciers. A number of GLOFs originating from lakes in the Cordillera Blanca have occurred over the last century, several of which have had catastrophic impacts on cities and communities downstream. Glaciologists and engineers in Peru have been studying the lakes of the Cordillera Blanca for many years and have identified several lakes that are considered dangerous. However, a systematic analysis of all the lakes in the Cordillera Blanca has never before been attempted. Some methodologies for this type of systematic analysis have been proposed (eg. Emmer and Vilimek 2014; Wang, et al. 2011), but as yet they have only been applied to a few select lakes in the Cordillera Blanca. This study uses remotely sensed data to study all of the lakes of the Glacial Lake Inventory published by the Glaciology and Water Resources Unit of Peru's National Water Authority (UGRH 2011). The objective of this study is to assign a level of potential hazard to each glacial lake in the Cordillera Blanca and to ascertain if any of the lakes beyond those that have already been studied might pose a danger to nearby populations. A number of parameters of analysis, both quantitative and qualitative, have been selected to assess the hazard level of each glacial lake in the Cordillera Blanca using digital elevation models, satellite imagery, and glacier outlines. These parameters are then combined to come up with a preliminary assessment of the hazard level of each lake; the equation weighting each parameter draws on previously published methodologies but is tailored to the regional characteristics

Birth Outcomes across Three Rural-Urban Typologies in the Finger Lakes Region of New York

Science.gov (United States)

Strutz, Kelly L.; Dozier, Ann M.; van Wijngaarden, Edwin; Glantz, J. Christopher

2012-01-01

Purpose: The study is a descriptive, population-based analysis of birth outcomes in the New York State Finger Lakes region designed to determine whether perinatal outcomes differed across 3 rural typologies. Methods: Hospital birth data for the Finger Lakes region from 2006 to 2007 were used to identify births classified as low birthweight (LBW),…

Lake Morphometry for NHD Lakes in California Region 18 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

Data.gov (United States)

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...

Great Lakes O shore Wind Project: Utility and Regional Integration Study

Energy Technology Data Exchange (ETDEWEB)

Sajadi, Amirhossein [Case Western Reserve Univ., Cleveland, OH (United States); Loparo, Kenneth A. [Case Western Reserve Univ., Cleveland, OH (United States); D' Aquila, Robert [General Electric (GE), Albany, NY (United States); Clark, Kara [National Renewable Energy Lab. (NREL), Golden, CO (United States); Waligorski, Joseph G. [FirstEnergy, Akron, OH (United States); Baker, Scott [PJM Interconnection, Audubon, PA (United States)

2016-06-30

This project aims to identify transmission system upgrades needed to facilitate offshore wind projects as well as operational impacts of offshore generation on operation of the regional transmission system in the Great Lakes region. A simulation model of the US Eastern Interconnection was used as the test system as a case study for investigating the impact of the integration of a 1000MW offshore wind farm operating in Lake Erie into FirstEnergy/PJM service territory. The findings of this research provide recommendations on offshore wind integration scenarios, the locations of points of interconnection, wind profile modeling and simulation, and computational methods to quantify performance, along with operating changes and equipment upgrades needed to mitigate system performance issues introduced by an offshore wind project.

Tendencies of ecological changes in the region of Ignalina NPP and in Lake Drukshiai

International Nuclear Information System (INIS)

Pashkauskas, R.; Mazeika, J.; Baubinas, R.

1999-01-01

Since 1979, when the construction of the Ignalina Nuclear Power Plant started, a group of specialists from Lithuania research and academic institutions began to investigate both Lake Drukshiai - the cooler of the Ignalina NPP and the neighbouring area. The investigations were aimed not only at monitoring the environmental consequences of the Ignalina NPP impact but also at forecasting changes of the ecosystems. The State Scientific Program 'Ignalina Nuclear Power Plant and the Environment' was the result of final stage of complex investigations. This conference paper contains data on the changes of thermal state and water balance of Lake Drukshiai, the effect of permanent thermal and chemical pollution on the chemical composition and hydrochemical regime, the pollution of the lake water, the geochemical-contaminated state, the condition, dynamics and the changes of hydrobiont communities in Lake Drukshiai. Radioecological and eco toxicological state of Ignalina NPP region and Lake Drukshiai is estimated as well as changes in Lake Drukshiai and Ignalina NPP surrounding area ecosystems under the combine anthropogenic impact of the plant influence are elucidated. The findings on medical and biological studies in the Ignalina NPP influence population zone and the evidence of impact of Ignalina NPP on social-territorial processes in the region are presented as well

Regional Photonics Initiative at the College of Lake County

Science.gov (United States)

Dulmes, Steven; Kellerhals, William

2017-01-01

The College of Lake County Regional Photonics Initiative project was motivated in part by the hiring of out-of-state technicians for local Photonics industry positions. Fifteen high paying employment opportunities during the recent recession could not be filled from the locally available workforce. Research on the current demand and future growth…

Vegetation Index, Lake Vegetation Index Regions.This layer describes the spatial extent of the North and South Lake Vegetation Index (LVI) biological regions, as described in Fore et al. 2007, Assessing the Biological Condition of Florida Lakes: Development of the Lake Veg, Published in 2008, 1:24000 (1in=2000ft) scale, Florida Department of Environmental Protection (FDEP).

Data.gov (United States)

NSGIC State | GIS Inventory — Vegetation Index dataset current as of 2008. Lake Vegetation Index Regions.This layer describes the spatial extent of the North and South Lake Vegetation Index (LVI)...

Air pollution and environmental justice in the Great Lakes region

Science.gov (United States)

Comer, Bryan

While it is true that air quality has steadily improved in the Great Lakes region, air pollution remains at unhealthy concentrations in many areas. Research suggests that vulnerable and susceptible groups in society -- e.g., minorities, the poor, children, and poorly educated -- are often disproportionately impacted by exposure to environmental hazards, including air pollution. This dissertation explores the relationship between exposure to ambient air pollution (interpolated concentrations of fine particulate matter, PM2.5) and sociodemographic factors (race, housing value, housing status, education, age, and population density) at the Census block-group level in the Great Lakes region of the United States. A relatively novel approach to quantitative environmental justice analysis, geographically weighted regression (GWR), is compared with a simplified approach: ordinary least squares (OLS) regression. While OLS creates one global model to describe the relationship between air pollution exposure and sociodemographic factors, GWR creates many local models (one at each Census block group) that account for local variations in this relationship by allowing the value of regression coefficients to vary over space, overcoming OLS's assumption of homogeneity and spatial independence. Results suggest that GWR can elucidate patterns of potential environmental injustices that OLS models may miss. In fact, GWR results show that the relationship between exposure to ambient air pollution and sociodemographic characteristics is non-stationary and can vary geographically and temporally throughout the Great Lakes region. This suggests that regulators may need to address environmental justice issues at the neighborhood level, while understanding that the severity of environmental injustices can change throughout the year.

Utilization of a Marketing Strategy at Naval Regional Medical Center Great Lakes, Great Lakes, Illinois

Science.gov (United States)

1983-06-01

22 Analysis of the Mare.....................22 Development of the Marketing Mix .. .......... 29 A Marketing Mix --Recommendations...problem. Marketing strategy, marketing mix and ultimately the marketing orientation will allow hospitals to persevere and possibly thrive in a somewhat...market are currently being met at Naval Regional Medical Center Great Lakes. The fourth objective is to demonstrate an appropriate marketing mix for

Water Quality and Evaluation of Pesticides in Lakes in the Ridge Citrus Region of Central Florida

Science.gov (United States)

Choquette, Anne F.; Kroening, Sharon E.

2009-01-01

Water chemistry, including major inorganic constituents, nutrients, and pesticide compounds, was compared between seven lakes surrounded by citrus agriculture and an undeveloped lake on the Lake Wales Ridge (herein referred to as the Ridge) in central Florida. The region has been recognized for its vulnerability to the leaching of agricultural chemicals into the subsurface due to factors including soils, climate, and land use. About 40 percent of Florida's citrus cultivation occurs in 'ridge citrus' areas characterized by sandy well drained soils, with the remainder in 'flatwoods citrus' characterized by high water tables and poorly drained soils. The lakes on the Ridge are typically flow-through lakes that exchange water with adjacent and underlying aquifer systems. This study is the first to evaluate the occurrence of pesticides in lakes on the Ridge, and also represents one of the first monitoring efforts nationally to focus on regional-scale assessment of current-use pesticides in small- to moderate-sized lakes (5 to 393 acres). The samples were collected between December 2003 and September 2005. The lakes in citrus areas contained elevated concentrations of major inorganic constituents (including alkalinity, total dissolved solids, calcium, magnesium, sodium, potassium, chloride, and sulfate), total nitrogen, pH, and pesticides compared to the undeveloped lake. Nitrate (as N) and total nitrogen concentrations were typically elevated in the citrus lakes, with maximum values of 4.70 and 5.19 mg/L (milligrams per liter), respectively. Elevated concentrations of potassium, nitrate, and other inorganic constituents in the citrus lakes likely reflect inputs from the surficial ground-water system that originated predominantly from agricultural fertilizers, soil amendments, and inorganic pesticides. A total of 20 pesticide compounds were detected in the lakes, of which 12 compounds exceeded the standardized reporting level of 0.06 ug/L (microgram per liter). Those

Limnological characteristics of 56 lakes in the Central Canadian Arctic Treeline Region

Directory of Open Access Journals (Sweden)

John P. SMOL

2003-02-01

Full Text Available Measured environmental variables from 56 lakes across the Central Canadian Treeline Region exhibited clear limnological differences among subpolar ecozones, reflecting strong latitudinal changes in biome characteristics (e.g. vegetation, permafrost, climate. Principal Components Analysis (PCA clearly separated forested sites from tundra sites based on distinct differences in limnological characteristics. Increases in major ions and related variables (e.g. dissolved inorganic carbon, DIC were higher in boreal forest sites in comparison to arctic tundra sites. The higher values recorded in the boreal forest lakes may be indirectly related to differences in climatic factors in these zones, such as the degree of permafrost development, higher precipitation and runoff, duration of ice-cover on the lakes, and thicker and better soil development. Similar to trends observed in DIC, substantially higher values for dissolved organic carbon (DOC were measured in boreal forest lakes than in arctic tundra lakes. This was likely due to higher amounts of catchment-derived DOC entering the lakes from coniferous leaf litter sources. Relative to arctic tundra lakes, boreal forest lakes had higher nutrient concentrations, particularly total nitrogen (TN, likely due to warmer conditions, a longer growing season, and higher precipitation, which would enhance nutrient cycling and primary productivity. Results suggest that modern aquatic environments at opposite sides of the central Canadian arctic treeline (i.e. boreal forest and arctic tundra exhibit distinct differences in water chemistry and physical conditions. These limnological trends may provide important information on possible future changes with additional warming.

PeRL: A circum-Arctic Permafrost Region Pond and Lake database

Science.gov (United States)

Muster, Sina; Roth, Kurt; Langer, Moritz; Lange, Stephan; Cresto Aleina, Fabio; Bartsch, Annett; Morgenstern, Anne; Grosse, Guido; Jones, Benjamin; Sannel, A.B.K.; Sjoberg, Ylva; Gunther, Frank; Andresen, Christian; Veremeeva, Alexandra; Lindgren, Prajna R.; Bouchard, Frédéric; Lara, Mark J.; Fortier, Daniel; Charbonneau, Simon; Virtanen, Tarmo A.; Hugelius, Gustaf; Palmtag, J.; Siewert, Matthias B.; Riley, William J.; Koven, Charles; Boike, Julia

2017-01-01

Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost Region Pond and Lake (PeRL) database presents the results of a circum-Arctic effort to map ponds and lakes from modern (2002–2013) high-resolution aerial and satellite imagery with a resolution of 5 m or better. The database also includes historical imagery from 1948 to 1965 with a resolution of 6 m or better. PeRL includes 69 maps covering a wide range of environmental conditions from tundra to boreal regions and from continuous to discontinuous permafrost zones. Waterbody maps are linked to regional permafrost landscape maps which provide information on permafrost extent, ground ice volume, geology, and lithology. This paper describes waterbody classification and accuracy, and presents statistics of waterbody distribution for each site. Maps of permafrost landscapes in Alaska, Canada, and Russia are used to extrapolate waterbody statistics from the site level to regional landscape units. PeRL presents pond and lake estimates for a total area of 1. 4 × 106 km2 across the Arctic, about 17 % of the Arctic lowland ( s.l.) land surface area. PeRL waterbodies with sizes of 1. 0 × 106 m2 down to 1. 0 × 102 m2 contributed up to 21 % to the total water fraction. Waterbody density ranged from 1. 0 × 10 to 9. 4 × 101 km−2. Ponds are the dominant waterbody type by number in all landscapes representing 45–99 % of the total waterbody number. The implementation of PeRL size distributions in land surface models will greatly improve the investigation and projection of surface inundation and carbon fluxes in permafrost lowlands. Waterbody maps, study area

Democratic Republic of Congo A Fertile Ground for Instability in the Great Lakes Region States

Science.gov (United States)

2017-06-09

ravaged by a brutal armed conflict. In comparison to the three past presidents, Joseph Kabila has managed to restore political stability and calm to much...DEMOCRATIC REPUBLIC OF CONGO-A FERTILE GROUND FOR INSTABILITY IN THE GREAT LAKES REGION STATES A thesis presented to the Faculty of...From - To) AUG 2016 – JUNE 2017 4. TITLE AND SUBTITLE Democratic Republic of Congo-A Fertile Ground for Instability in the Great Lakes Region

Lake Morphometry for NHD Lakes in Upper Colorado Region 14 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in North East Region 1 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Lower Colorado Region 15 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Upper Mississippi Region 7 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Rio Grande Region 13 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Pacific Northwest Region 17 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Lower Mississippi Region 8 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Texas-Gulf Region 12 HUC

Data.gov (United States)

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...

Analysis of Thermal Structure of Arctic Lakes at Local and Regional Scales Using in Situ and Multidate Landsat-8 Data

Science.gov (United States)

Huang, Yan; Liu, Hongxing; Hinkel, Kenneth; Yu, Bailang; Beck, Richard; Wu, Jianping

2017-11-01

The Arctic coastal plain is covered with numerous thermokarst lakes. These lakes are closely linked to climate and environmental change through their heat and water budgets. We examined the intralake thermal structure at the local scale and investigated the water temperature pattern of lakes at the regional scale by utilizing extensive in situ measurements and multidate Landsat-8 remote sensing data. Our analysis indicates that the lake skin temperatures derived from satellite thermal sensors during most of the ice-free summer period effectively represent the lake bulk temperature because the lakes are typically well-mixed and without significant vertical stratification. With the relatively high-resolution Landsat-8 thermal data, we were able to quantitatively examine intralake lateral temperature differences and gradients in relation to geographical location, topography, meteorological factors, and lake morphometry for the first time. Our results suggest that wind speed and direction not only control the vertical stratification but also influences lateral differences and gradients of lake surface temperature. Wind can considerably reduce the intralake temperature gradient. Interestingly, we found that geographical location (latitude, longitude, distance to the ocean) and lake morphometry (surface size, depth, volume) not only control lake temperature regionally but also affect the lateral temperature gradient and homogeneity level within each individual lake. For the Arctic coastal plain, at regional scales, inland and southern lakes tend to have larger horizontal temperature differences and gradients compared to coastal and northern lakes. At local scales, large and shallow lakes tend to have large lateral temperature differences relative to small and deep lakes.

Cold Lake-Beaver River water management study update: Report of the Cold Lake Regional Water Management Task Force

International Nuclear Information System (INIS)

1994-01-01

The Cold Lake Regional Water Management Task Force was formed in 1992, comprising representatives from local governments, aboriginal groups, the oil industry, and the public. The Task Force's mandate was to advise Alberta Environmental Protection on updating the Cold Lake-Beaver River Water Management Plan, taking into acocunt the views and concerns of the public, industry, and local governments. Industrial water use was found to be the key issue to be addressed in the plan update, so the Task Force focused on reviewing industrial water supply options and developing recommendations on the appropriate water supply to meet long-term requirements. A subcommittee was established to monitor groundwater use by the heavy oil industry. This committee took readings at Imperial Oil's water production and observation wells on a biweekly basis. Nine options for supplying industrial water requirements were examined and evaluated using criteria including supply reliability, economic factors, and impacts on other users and the environment. The Task Force found that the preferred source of water for industrial use is the North Saskatchewan River, to be accessed by a water pipeline. The second and less desirable source of water for industrial use would be a system of weirs on Cold or Primrose Lakes and Wolf Lake, supplemented by the use of brackish water to the maximum extent possible. In the interim, industry was recommended to maximize its use of brackish water and continue to use surface and ground water within existing license limits. Other recommendations were to form provincial or regional boards to oversee water use and issue water licenses, to treat water as a resource, and to establish a fee for industrial use of water. 3 figs., 5 tabs

Delineating the Drainage Structure and Sources of Groundwater Flux for Lake Basaka, Central Rift Valley Region of Ethiopia

Directory of Open Access Journals (Sweden)

Megersa Olumana Dinka

2017-11-01

Full Text Available As opposed to most of the other closed basin type rift valley lakes in Ethiopia, Lake Basaka is found to be expanding at an alarming rate. Different studies indicated that the expansion of the lake is challenging the socio-economics and environment of the region significantly. This study result and previous reports indicated that the lake’s expansion is mostly due to the increased groundwater (GW flux to the lake. GW flux accounts for about 56% of the total inflow in recent periods (post 2000 and is found to be the dominant factor for the hydrodynamics and existence of the lake. The analysis of the drainage network for the area indicates the existence of a huge recharge area on the western and upstream side of the catchment. This catchment has no surface outlet; hence most of the incoming surface runoff recharges the GW system. The recharge area is the main source of GW flux to the lake. In addition to this, the likely sources/causes of GW flux to the lake could be: (i an increase of GW recharge following the establishment of irrigation schemes in the region; (ii subsurface inflow from far away due to rift system influence, and (iii lake neotectonism. Overall, the lake’s expansion has damaging effect to the region, owing to its poor water quality; hence the identification of the real causes of GW flux and mitigation measures are very important for sustainable lake management. Therefore a comprehensive and detailed investigation of the parameters related to GW flux and the interaction of the lake with the GW system of the area is highly recommended.

Spatial and Temporal Trends of Snowfall in Central New York - A Lake Effect Dominated Region

Science.gov (United States)

Hartnett, Justin Joseph

Central New York is located in one of the snowiest regions in the United States, with the city of Syracuse, New York the snowiest metropolis in the nation. Snowfall in the region generally begins in mid-November and lasts until late-March. Snow accumulation occurs from a multitude of conditions: frontal systems, mid-latitude cyclones, Nor'easters, and most notably lake-effect storms. Lake effect snowfall (LES) is a difficult parameter to forecast due to the isolated and highly variable nature of the storm. Consequently, studies have attempted to determine changes in snowfall for lake-effect dominated regions. Annual snowfall patterns are of particular concern as seasonal snowfall totals are vital for water resources, winter businesses, agriculture, government and state agencies, and much more. Through the use of snowfall, temperature, precipitation, and location data from the National Weather Service's Cooperative Observer Program (COOP), spatial and temporal changes in snowfall for Central New York were determined. In order to determine climatic changes in snowfall, statistical analyses were performed (i.e. least squares estimation, correlations, principal component analyses, etc.) and spatial maps analyzed. Once snowfall trends were determined, factors influencing the trends were examined. Long-term snowfall trends for CNY were positive for original stations (˜0.46 +/- 0.20 in. yr -1) and homogenously filtered stations (0.23 +/- 0.20 in. yr -1). However, snowfall trends for shorter time-increments within the long-term period were not consistent, as positive, negative, and neutral trends were calculated. Regional differences in snowfall trends were observed for CNY as typical lake-effect areas (northern counties, the Tug Hill Plateau and the Southern Hills) experienced larger snowfall trends than areas less dominated by LES. Typical lake-effect months (December - February) experienced the greatest snowfall trend in CNY compared to other winter months. The

The influence of climate change to European Lakes, with a special emphasis in the Balkan Region

International Nuclear Information System (INIS)

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

Quantitative Development and Distribution of Zooplankton in Medium Lakes of the Kostanay Region (North Kazakhstan Region)

Science.gov (United States)

Aubakirova, Gulzhan A.; Syzdykov, Kuanysh N.; Kurzhykayev, Zhumagazy; Uskenov, Rashit B.; Narbayev, Serik; Begenova, Ainagul B.; Zhumakayeva, Aikumys N.; Sabdinova, Dinara K.; Akhmedinov, Serikbay N.

2016-01-01

The assessment of water resources plays an important environmental and economic role, since it allows developing an effective program of regional development with regard to the environmental load. The hydro-chemical regime of lakes includes water temperature, content of biogenic elements, total mineralization, oxygen regime, and other parameters…

Progress in study of Prespa Lake using nuclear and related techniques (IAEA Regional Project RER/8/008)

International Nuclear Information System (INIS)

Anovski, Todor

2001-09-01

One of the main objective of the IAEA - Regional project RER/8/008 entitled Study of Prespa Lake Using Nuclear and Related Techniques was to provide a scientific basis for sustainable and environmental management of the Lake Prespa (Three lakes: Ohrid, Big Prespa and Small Prespa are on the borders between Albania, Republic of Macedonia and Greece, and are separated by the Mali i Thate and Galichica, mostly Carstificated mountains), see Fig. 1. In this sense investigations connected with the hydrogeology, water quality (Physics-chemical, biological and radiological characteristics) and water balance determination by application of Environmental isotopes ( i.e. H,D,T,O-18,O-18 etc.,) distribution, artificial water tracers and other relevant analytical techniques such as: AAS, HPLC, Total α and β-activity, α and γ-spectrometry as well as ultra sonic measurements (defining of the Lake bottom profile) through regional cooperation / Scientists from Albania, Greece and Republic of Macedonia, participated in the implementation of the Project/ during one hydrological year, had been initiated and valuable results obtained, a part of which are presented in this report. This cooperation was the only way for providing necessary data for better understanding beside the other, of the water quality of the Prespa Lake and its hydrological relationship to Ohrid Lake too, representing a unique regional hydro system in the world. (Author)

Scale and watershed features determine lake chemistry patterns across physiographic regions in the far north of Ontario, Canada

Directory of Open Access Journals (Sweden)

Josef MacLeod

2016-11-01

Full Text Available Changes in the far north of Ontario (>50°N latitude, like climate warming and increased industrial development, will have direct effects on watershed characteristics and lakes. To better understand the nature of remote northern lakes that span the Canadian Shield and Hudson Bay Lowlands, and to address the pressing need for limnological data for this vast, little-studied area of Ontario, lake chemistry surveys were conducted during 2011-2012. Lakes at the transition between these physiographic regions displayed highly variable water chemistry, reflecting the peatland landscape with a mix of bog and fen watersheds, and variations in the extent of permafrost. In the transition area, Shield and Lowlands lakes could not be clearly differentiated based on water chemistry; peat cover decouples, to varying degrees, the lakes from the influences of bedrock and surficial deposits. Regional chemistry differences were apparent across a much broader area of northern Ontario, due to large-scale spatial changes in geology and in the extent of peatlands and permafrost.  Shield lakes in the far northwest of Ontario had Ca, Mg, and TP concentrations markedly higher than those of many Lowlands lakes and previously studied Shield lakes south of 50°N, related to an abundance of lacustrine and glacial end-moraine deposits in the north.

Expanded spatial extent of the Medieval Climate Anomaly revealed in lake-sediment records across the boreal region in northwest Ontario.

Science.gov (United States)

Laird, Kathleen R; Haig, Heather A; Ma, Susan; Kingsbury, Melanie V; Brown, Thomas A; Lewis, C F Michael; Oglesby, Robert J; Cumming, Brian F

2012-09-01

Multi-decadal to centennial-scale shifts in effective moisture over the past two millennia are inferred from sedimentary records from six lakes spanning a ~250 km region in northwest Ontario. This is the first regional application of a technique developed to reconstruct drought from drainage lakes (open lakes with surface outlets). This regional network of proxy drought records is based on individual within-lake calibration models developed using diatom assemblages collected from surface sediments across a water-depth gradient. Analysis of diatom assemblages from sediment cores collected close to the near-shore ecological boundary between benthic and planktonic diatom taxa indicated this boundary shifted over time in all lakes. These shifts are largely dependent on climate-driven influences, and can provide a sensitive record of past drought. Our lake-sediment records indicate two periods of synchronous signals, suggesting a common large-scale climate forcing. The first is a period of prolonged aridity during the Medieval Climate Anomaly (MCA, c. 900-1400 CE). Documentation of aridity across this region expands the known spatial extent of the MCA megadrought into a region that historically has not experienced extreme droughts such as those in central and western north America. The second synchronous period is the recent signal of the past ~100 years, which indicates a change to higher effective moisture that may be related to anthropogenic forcing on climate. This approach has the potential to fill regional gaps, where many previous paleo-lake depth methods (based on deeper centrally located cores) were relatively insensitive. By filling regional gaps, a better understanding of past spatial patterns in drought can be used to assess the sensitivity and realism of climate model projections of future climate change. This type of data is especially important for validating high spatial resolution, regional climate models. © 2012 Blackwell Publishing Ltd.

Imagining the Great Lakes Region: discourses and practices of civil society regional approaches for peacebuilding in Rwanda, Burundi and DR Congo

NARCIS (Netherlands)

Leeuwen, van M.

2008-01-01

The idea has gained ground in recent years that, as conflicts in the countries of the Great Lakes Region are strongly interlinked, regional approaches are necessary to resolve them. This interest in regional dimensions of conflict and peacebuilding also gains currency in other parts of the world.

Great Lakes

Science.gov (United States)

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

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

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

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

Science.gov (United States)

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-03-07

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

Lake Morphometry for NHD Lakes in Souris Red Rainy Region 9 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in Arkansas White Red Region 11 HUC

Data.gov (United States)

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...

ANALYSIS OF MERCURY IN VERMONT AND NEW HAMPSHIRE LAKES: EVALUATION OF THE REGIONAL MERCURY CYCLING MODEL

Science.gov (United States)

An evaluation of the Regional Mercury Cycling Model (R-MCM, a steady-state fate and transport model used to simulate mercury concentrations in lakes) is presented based on its application to a series of 91 lakes in Vermont and New Hampshire. Visual and statistical analyses are pr...

Mapping lake level changes using ICESat/GLAS satellite laser altimetry data: a case study in arid regions of central Asia

Science.gov (United States)

Li, JunLi; Fang, Hui; Yang, Liao

2011-12-01

Lakes in arid regions of Central Asia act as essential components of regional water cycles, providing sparse but valuable water resource for the fragile ecological environments and human lives. Lakes in Central Asia are sensitive to climate change and human activities, and great changes have been found since 1960s. Mapping and monitoring these inland lakes would improve our understanding of mechanism of lake dynamics and climatic impacts. ICESat/GLAS satellite laser altimetry provides an efficient tool of continuously measuring lake levels in these poorly surveyed remote areas. An automated mapping scheme of lake level changes is developed based on GLAS altimetry products, and the spatial and temporal characteristics of 9 typical lakes in Central Asia are analyzed to validate the level accuracies. The results show that ICESat/GLAS has a good performance of lake level monitoring, whose patterns of level changes are the same as those of field observation, and the max differences between GLAS and field data is 3cm. Based on the results, it is obvious that alpine lakes are increasing greatly in lake levels during 2003-2009 due to climate change, while open lakes with dams and plain endorheic lakes decrease dramatically in water levels due to human activities, which reveals the overexploitation of water resource in Central Asia.

Environmental status of the Lake Michigan region. Volume 3. Chemistry of Lake Michigan

Energy Technology Data Exchange (ETDEWEB)

Torrey, M S

1976-05-01

The report is a synoptic review of data collected over the past twenty years on the chemistry of Lake Michigan. Changes in water quality and sediment chemistry, attributable to cultural and natural influences, are considered in relation to interacting processes and factors controlling the distribution and concentration of chemical substances within the Lake. Temperature, light, and mixing processes are among the important natural influences that affect nutrient cycling, dispersal of pollutants, and fate of materials entering the Lake. Characterization of inshore-offshore and longitudinal differences in chemical concentrations and sediment chemistry for the main body of the Lake is supplemented by discussion of specific areas such as Green Bay and Grand Traverse Bay. Residues, specific conductance, dissolved oxygen, major and trace nutrients, and contaminants are described in the following context: biological essentiality and/or toxicity, sources to the Lake, concentrations in the water column and sediments, chemical forms, seasonal variations and variation with depth. A summary of existing water quality standards, statutes, and criteria applicable to Lake Michigan is appended.

Controls on the geochemical evolution of Prairie Pothole Region lakes and wetlands over decadal time scales

Science.gov (United States)

Goldhaber, Martin B.; Mills, Christopher T.; Mushet, David M.; McCleskey, R. Blaine; Rover, Jennifer

2016-01-01

One hundred sixty-seven Prairie Pothole lakes, ponds and wetlands (largely lakes) previously analyzed chemically during the late 1960’s and early to mid-1970’s were resampled and reanalyzed in 2011–2012. The two sampling periods differed climatically. The earlier sampling took place during normal to slightly dry conditions, whereas the latter occurred during and immediately following exceptionally wet conditions. As reported previously in Mushet et al. (2015), the dominant effect was expansion of the area of these lakes and dilution of their major ions. However, within that context, there were significant differences in the evolutionary pathways of major ions. To establish these pathways, we employed the inverse modeling computer code NetpathXL. This code takes the initial and final lake composition and, using mass balance constrained by the composition of diluting waters, and input and output of phases, calculates plausible geochemical evolution pathways. Despite the fact that in most cases major ions decreased, a subset of the lakes had an increase in SO42−. This distinction is significant because SO42− is the dominant anion in a majority of Prairie Pothole Region wetlands and lakes. For lakes with decreasing SO42−, the proportion of original lake water required for mass balance was subordinate to rainwater and/or overland flow. In contrast, lakes with increasing SO42− between the two sampling episodes tended to be dominated by original lake water. This suite of lakes tended to be smaller and have lower initial SO42−concentrations such that inputs of sulfur from dissolution of the minerals gypsum or pyrite had a significant impact on the final sulfur concentration given the lower dilution factors. Thus, our study provides context for how Prairie Pothole Region water bodies evolve geochemically as climate changes. Because wetland geochemistry in turn controls the ecology of these water bodies, this research contributes to the prediction of the

Results of photochemical modeling sensitivity analyses in the Lake Michigan region: Current status of Lake Michigan Ozone Control Program (LMOP) modeling

Energy Technology Data Exchange (ETDEWEB)

Dolwick, P.D. [Lake Michigan Air Directors Consortium, Des Plaines, IL (United States); Kaleel, R.J. [Illinois Environmental Protection Agency, Springfield, IL (United States); Majewski, M.A. [Wisconsin Dept. of Natural Resources, Madison, WI (United States)

1994-12-31

The four states that border Lake Michigan are cooperatively applying a state-of-the-art nested photochemical grid model to assess the effects of potential emission control strategies on reducing elevated tropospheric ozone concentrations in the region to levels below the national ambient air quality standard. In order to provide an extensive database to support the application of the photochemical model, a substantial data collection effort known as the Lake Michigan Ozone Study (LMOS) was completed during the summer of 1991. The Lake Michigan Ozone Control Program (LMOP) was established by the States of Illinois, Wisconsin, Michigan, and Indiana to carry out the application of the modeling system developed from the LMOS, in terms of developing the attainment demonstrations required from this area by the Clean Air Act Amendments of 1990.

Ecology of playa lakes

Science.gov (United States)

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.

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China

Science.gov (United States)

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-03-01

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

Regional Climate Models as a Tool for Assessing Changes in the Laurentian Great Lakes Net Basin Supply

Science.gov (United States)

Music, B.; Mailhot, E.; Nadeau, D.; Irambona, C.; Frigon, A.

2017-12-01

Over the last decades, there has been growing concern about the effects of climate change on the Great Lakes water supply. Most of the modelling studies focusing on the Laurentian Great Lakes do not allow two-way exchanges of water and energy between the atmosphere and the underlying surface, and therefore do not account for important feedback mechanisms. Moreover, energy budget constraint at the land surface is not usually taken into account. To address this issue, several recent climate change studies used high resolution Regional Climate Models (RCMs) for evaluating changes in the hydrological regime of the Great Lakes. As RCMs operate on the concept of water and energy conservation, an internal consistency of the simulated energy and water budget components is assured. In this study we explore several recently generated Regional Climate Model (RCM) simulations to investigate the Great Lakes' Net Basin Supply (NBS) in a changing climate. These include simulations of the Canadian Regional Climate Model (CRCM5) supplemented by simulations from several others RCMs participating to the North American CORDEX project (CORDEX-NA). The analysis focuses on the NBS extreme values under nonstationary conditions. The results are expected to provide useful information to the industries in the Great Lakes that all need to include accurate climate change information in their long-term strategy plans to better anticipate impacts of low and/or high water levels.

Lake Area Changes and Their Influence on Factors in Arid and Semi-Arid Regions along the Silk Road

Directory of Open Access Journals (Sweden)

Chao Tan

2018-04-01

Full Text Available In the context of global warming, the changes in major lakes and their responses to the influence factors in arid and semi-arid regions along the Silk Road are especially important for the sustainable development of local water resources. In this study, the areas of 24 lakes were extracted using MODIS NDVI data, and their spatial-temporal characteristics were analyzed. In addition, the relationship between lake areas and the influence factors, including air temperature, precipitation, evapotranspiration, land use and land cover change (LULCC and population density in the watersheds, were investigated. The results indicated that the areas of most lakes shrank, and the total area decreased by 22,189.7 km2 from 2001 to 2016, except for those of the lakes located on the Qinghai-Tibetan Plateau. The air temperature was the most important factor for all the lakes and increased at a rate of 0.113 °C/a during the past 16 years. LULCC and the increasing population density markedly influenced the lakes located in the middle to western parts of this study area. Therefore, our results connecting lake area changes in the study region highlight the great challenge of water resources and the urgency of implementation of the green policy in the One Belt and One Road Initiative through international collaboration.

The magnetic properties of the Lake Bolshoe Yarovoe (Altai Region, Russia) sediments

Science.gov (United States)

Kosareva, Lina; Nourgaliev, Danis; Nurgalieva, Nuriia; Shcherbakov, Valeriy; Kuzina, Diliara; Antonenko, Vadim; Akhmerov, Rinaz; Evtugyn, Vladimir; Vorob'ev, Vyacheslav

2017-04-01

Magnetic minerals of modern lake sediments provide unique source of information for climate changes, regionally and globally as environmental variations are recorded by them with high resolution. Here we report results of magnetic analysis of the endorheic bitter-salty lake Bolshoe Yarovoe located in the Altai Region, Russia. The lake is the deepest one in the Kulunda Steppe with the average depth 4 m and with the catchment area about 560 km2. Five cores were drileld during field research conducted by the Institute of Geology and Petroleum Technologies (Kazan Federal University, Russia) in 2008. Average length of cores is 4 m. The samples were studied using radiocarbon dating, magnetic susceptibility, NRM measurements, coercivity spectrometry, thermomagnetic analysis, TEM and SEM microscopy. The main components of the sediments magnetization, their variability, defined features of sedimentation processes, also the contribution of the paramagnetic, ferromagnetic, superparamagnetic components are identified. Data variability of the paramagnetic component revealed that the lower part of the section is characterized by a gradual increase in revenues of the clay material. The presence of erosion was detected around of 7500 years ago marking occurrence of a fall of the lake level during this period. After this the flow of clay particles was steady with small fluctuations only, indicating the stabilization of sedimentation processes. Ferromagnetic fraction is mainly represented by magnitofossils of different forms, sizes and grain preservation. Such changes may be related to many factors, such as climate, nutrient availability, and environmental variability. Possible relationships between magnitofossil morphology, their magnetic signal and the depositional environment changes are proposed. The work was carried out according to the Russian Government's Program of Competitive Growth of Kazan Federal University.

Preliminary measurements of tritium, deuterium and oxygen-18 in lakes and groundwater of volcanic Rotorua region, New Zealand

International Nuclear Information System (INIS)

Taylor, C.B.; Freestone, H.J.; Nairn, I.A.

1977-06-01

This report presents an initial survey of the isotopic characteristics of non-hydrothermal waters of Rotorua region. Measurements of deuterium, oxygen and tritium have been made on samples collected between 1970 and 1973. Some major springs emerging close to land-locked lakes have been identified as containing mixtures of lake-derived water and precipitation-derived recharge in the catchments between lake and spring. The stable isotope composition of precipitation-recharged groundwater occupies a fairly narrow range, but is nevertheless seperable into two distinct isotopic families. The circumstances leading to these isotopic differences are not yet fully understood. This isotopic data has been gathered with a view to identifying hydrological problems in the region capable of study by isotopic methods and as essential background data to studies of the region's many hydrothermal systems. (auth.)

The regional and global significance of nitrogen removal in lakes and reservoirs

Science.gov (United States)

Harrison, J.A.; Maranger, R.J.; Alexander, Richard B.; Giblin, A.E.; Jacinthe, P.-A.; Mayorga, Emilio; Seitzinger, S.P.; Sobota, D.J.; Wollheim, W.M.

2009-01-01

Human activities have greatly increased the transport of biologically available nitrogen (N) through watersheds to potentially sensitive coastal ecosystems. Lentic water bodies (lakes and reservoirs) have the potential to act as important sinks for this reactive N as it is transported across the landscape because they offer ideal conditions for N burial in sediments or permanent loss via denitrification. However, the patterns and controls on lentic N removal have not been explored in great detail at large regional to global scales. In this paper we describe, evaluate, and apply a new, spatially explicit, annual-scale, global model of lentic N removal called NiRReLa (Nitrogen Retention in Reservoirs and Lakes). The NiRReLa model incorporates small lakes and reservoirs than have been included in previous global analyses, and also allows for separate treatment and analysis of reservoirs and natural lakes. Model runs for the mid-1990s indicate that lentic systems are indeed important sinks for N and are conservatively estimated to remove 19.7 Tg N year-1 from watersheds globally. Small lakes (<50 km2) were critical in the analysis, retaining almost half (9.3 Tg N year -1) of the global total. In model runs, capacity of lakes and reservoirs to remove watershed N varied substantially at the half-degree scale (0-100%) both as a function of climate and the density of lentic systems. Although reservoirs occupy just 6% of the global lentic surface area, we estimate they retain ~33% of the total N removed by lentic systems, due to a combination of higher drainage ratios (catchment surface area:lake or reservoir surface area), higher apparent settling velocities for N, and greater average N loading rates in reservoirs than in lakes. Finally, a sensitivity analysis of NiRReLa suggests that, on-average, N removal within lentic systems will respond more strongly to changes in land use and N loading than to changes in climate at the global scale. ?? 2008 Springer Science

Regional distribution and relevance in paleonvironmental studies of lakes in the Tatra Mts. (Western Carpathians

Directory of Open Access Journals (Sweden)

Joanna POCIASK-KARTECZKA

2014-11-01

Full Text Available Scientific limnological research in the Tatra Mountains were initiated by Stanislaw Staszic in the early XIX century.  After the World War II, the evolution of Tatra lakes was investigated by Kondracki, Klimaszewski, Baumgart-Kotarba and. Extensive paleolimnological investigations in the Tatra Mountains were started by the group of scientists led by K. Starmach in the beginning of the second half of the 20th century. There has been not much research concerned to the regional distribution of lakes and their properties in the Tatra Mountains (Pociask-Karteczka 2013. Very early division of lakes presented A. Gadomski (1922, which distinguished four types of lakes: a tarns (cirque lake or corrie loch, b bedrock-dammed lakes, c moraine lakes. This division was concerned in subsequent publications (Choiński 2007. M. Lukniš (1973, 1985 recognized additional types: kettles and landslide-dammed lakes and M. Klimaszewski (1988 – inter-sheepback lakes. J. Pacl and K. Wit-Jóźwik in Klima Tatier (Pacl, Wit-Jóźwik 1974 were focused on the temperature of water in lakes in Polish and Slovak parts and M. Borowiak (2000a,b provided a comprehensive analysis of types, dimensions, temperature and chemical composition of water in lakes in the Tatra Mountains.According to present day state of knowledge, one may distinguish following genetic types of lakes: I glacial, II not-glacial. There are four types of the glacial origin lakes in the Tatra Mountains (Fig. 1: a tarns (cirque lakes or corrie loch, b bedrock-moraine dammed lakes, c inter-sheepback lakes, d moraine lakes, e kettles.Most of lakes in the Tatra Mountains are tarns and bedrock-moraine dammed lakes, and they are located at the elevation over 1400 m a.s.l. in the Western Tatra Mountains, and over 1600 m a.s.l. in the High Tatra Mountains. Some of them are paternoster lakes – a series of stair-stepped lakes formed in individual rock basins aligned down the course of a glaciated valley. Lakes in

Lake Afdera: a threatened saline lake in Ethiopia | Getahun | SINET ...

African Journals Online (AJOL)

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 ...

Assessment of biomass cogeneration in the Great Lakes region

International Nuclear Information System (INIS)

Burnham, M.; Easterly, J.L.

1994-01-01

Many biomass cogeneration facilities have successfully entered into power sales agreements with utilities across the country, often after overcoming various difficulties or barriers. Under a project sponsored by the Great Lakes Regional Biomass Energy Program of the U.S. Department of Energy, DynCorp sm-bullet Meridian has conducted a survey of biomass facilities in the seven Great Lakes states, selecting 10 facilities for case studies with at least one facility in each of the seven states. The purpose of the case studies was to address obstacles that biomass processors face in adding power production to their process heat systems, and to provide examples of successful strategies for entering into power sales agreements with utilities. The case studies showed that the primary incentives for investing in cogeneration and power sales are to reduce operating costs through improved biomass waste management and lower energy expenditures. Common barriers to cogeneration and power sales were high utility stand-by charges for unplanned outages and low utility avoided cost payments due to excess utility generation capacity

Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries

International Nuclear Information System (INIS)

Thevenon, Florian; Graham, Neil D.; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John

2011-01-01

This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750–1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (> 100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. Highlights: ► Natural sources dominated trace element

The regional abundance and size distribution of lakes and reservoirs in the United States and implication for estimates of global lake extent

Science.gov (United States)

McDonald, Cory P.; Rover, Jennifer; Stets, Edward G.; Striegl, Robert G.

2012-01-01

We analyzed complete geospatial data for the 3.5 million lakes and reservoirs larger than 0.001 km2, with a combined surface area of 131,000 km2, in the contiguous United States (excluding the Laurentian Great Lakes) and identified their regional distribution characteristics. For Alaska, we also analyzed (1) incomplete data that suggest that the state contains 1–2.5 million lakes larger than 0.001 km2 covering over 50,000 km2 and (2) localized high-resolution (5 m) data that suggest that the number of very small water bodies ( 0.001 km2 in some areas. The Pareto distribution cannot accurately describe the lake abundance-size relationship across the entire size spectrum, and extrapolation of this density function to small size classes has likely resulted in the overestimation of the number of small lakes in the world. While small water bodies dominate in terms of numbers, they are not numerous enough to dominate in terms of surface area, as has been previously suggested. Extending our results to the global scale suggests that there are on the order of 64 million water bodies larger than 0.001 km2 in the world, with a total surface area of approximately 3.8 million km2.

The 24 July 2008 outburst flood at the western Zyndan glacier lake and recent regional changes in glacier lakes of the Teskey Ala-Too range, Tien Shan, Kyrgyzstan

Directory of Open Access Journals (Sweden)

C. Narama

2010-04-01

Full Text Available On 24 July 2008, a glacier lake outburst flood (GLOF occurred at the western (w- Zyndan glacier lake in the Tong District of Ysyk-Köl Oblast, Kyrgyzstan. The flood killed three people and numerous livestock, destroyed infrastructure, and devastated potato and barley crops as well as pastures. Tuurasuu village and a downstream reservoir on the Zyndan river escaped heavy damage because the main flood was diverted toward the Tong river. RTK-GPS and satellite data (Landsat 7 ETM+, ALOS/PRISM, and ALOS/AVNIR-2 reveal that the flood reduced the lake area from 0.0422 km² to 0.0083 km², discharging 437 000 m³ of water. This glacier lake was not present in a Landsat 7 ETM+ image taken on 26 April 2008. It formed rapidly over just two and half months from early May to the late July, when large amounts of snow and glacier melt water became trapped in a basin in the glacier terminus area, blocked by temporary closure of the drainage channel through the terminal moraine that included much dead-ice. In the same mountain region, most other glacier-lake expansions were not particularly large during the period from 1999–2008. Although events like the w-Zyndan glacier lake outburst occur infrequently in the high Central Asian mountains, such fast developing, short-lived lakes are particularly dangerous and not easy to monitor using satellite data. Appropriate measures to protect against such lake outburst hazards in this region include educating residents on glacier hazards and monitoring techniques, providing frequently updated maps of glacier lakes, and planning and monitoring land-use, including house locations.

Improving regional climate and hydrological forecasting following the record setting flooding across the Lake Ontario - St. Lawrence River system

Science.gov (United States)

Gronewold, A.; Seglenieks, F.; Bruxer, J.; Fortin, V.; Noel, J.

2017-12-01

In the spring of 2017, water levels across Lake Ontario and the upper St. Lawrence River exceeded record high levels, leading to widespread flooding, damage to property, and controversy over regional dam operating protocols. Only a few years earlier, water levels on Lakes Superior, Michigan, and Huron (upstream of Lake Ontario) had dropped to record low levels leading to speculation that either anthropogenic controls or climate change were leading to chronic water loss from the Great Lakes. The contrast between low water level conditions across Earth's largest lake system from the late 1990s through 2013, and the rapid rise prior to the flooding in early 2017, underscores the challenges of quantifying and forecasting hydrologic impacts of rising regional air and water temperatures (and associated changes in lake evaporation) and persistent increases in long-term precipitation. Here, we assess the hydrologic conditions leading to the recent record flooding across the Lake Ontario - St. Lawrence River system, with a particular emphasis on understanding the extent to which those conditions were consistent with observed and anticipated changes in historical and future climate, and the extent to which those conditions could have been anticipated through improvements in seasonal climate outlooks and hydrological forecasts.

A fugacity model for source determination of the Lake Baikal region pollution with polychlorinated Biphenyls

Energy Technology Data Exchange (ETDEWEB)

Sofiev, M. [Finnish Meteorological Inst., Helsinki (Finland); Galperin, M.; Maslyaev, A. [Inst. of Program Systems, Pereslavl-Zalesskiy (Russian Federation); McLachlan, M. [Stockholm Univ. (Sweden); Wania, F. [Toronto Univ. (Canada)

2004-09-15

PCBs were discovered in the Lake Baikal ecosystem by Malakhov et al. and Bobovnikova et al. A follow up to the initial study showed no decrease over 1981-1989 4, in contrast to what has been observed in other water bodies in the industrialised world. Further studies also showed the contamination in pinnipeds to be among the highest measured anywhere. Above studies and other data suggested a presence of a strong local PCB source (or several ones), which has had a widespread adverse effect for the whole region. To locate the source, Mamontov et al. collected samples from 34 sites over the region, the analysis of which showed a gradient of a factor of 1000, with the lowest concentrations at the north-east of Lake Baikal and the highest concentrations close to the city of Usolye Sibirskoye, a centre of the chemical industry in the Angara River valley. A continuous decrease in the soil contamination was observed along the path from Usolye Sibirskoye up the Angara River valley to Lake Baikal and from there north-eastward along the lake. These results indicate that there was (and perhaps still is) a major source of PCBs in the Usolye area, from where the PCBs are dispersed over the region. However, various obstacles prevent direct observations of potential sources. Therefore, a mathematical modelling approach was adopted in a currently ongoing INTAS project aiming to shed some more light on this problem. The model principles, setup and the results of the first experiments are presented in the current paper.

An Overview of Sediment Organic Matter Records of Human Eutrophication in the Laurentian Great Lakes Region

Energy Technology Data Exchange (ETDEWEB)

Meyers, Philip A. [University of Michigan, Department of Geological Sciences (United States)], E-mail: pameyers@umich.ed

2006-12-15

The isotopic and molecular compositions of organic matter buried in lake sediments provide information that helps to reconstruct past environmental conditions and to assess impacts of humans on local ecosystems. This overview of sedimentary records from the North American Great Lakes region describes examples of applications of organic geochemistry to paleolimnological reconstructions. These lakes experienced a succession of human-induced environmental changes that started after completion of the Erie Canal in 1825. Agricultural deforestation in the mid-nineteenth century released soil nutrients that increased algal productivity and caused an associated increase in algal biomarkers in sediment records. Eutrophication that accompanied magnified delivery of municipal nutrients to the lakes in the 1960s and 1970s created excursions to less negative {delta}{sup 13}C values in sediment organic matter. Increased organic carbon mass accumulation rates mirror the isotopic evidence of eutrophication in the Great Lakes.

Great Lakes Literacy Principles

Science.gov (United States)

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.

Glacial lake inventory and lake outburst potential in Uzbekistan.

Science.gov (United States)

Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

2017-08-15

Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m 2 . As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries.

Science.gov (United States)

Thevenon, Florian; Graham, Neil D; Chiaradia, Massimo; Arpagaus, Philippe; Wildi, Walter; Poté, John

2011-12-15

This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (>100 μg Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of a rural demonstration program to increase seat belt use in the Great Lakes Region.

Science.gov (United States)

2009-03-01

Six States in the Great Lakes Region (Region 5) participated in a Rural Demonstration Program to increase seat belt : use in rural areas and among high-risk occupants, such as young males and occupants of pickup trucks. These : efforts, which include...

PeRL: a circum-Arctic Permafrost Region Pond and Lake database

Directory of Open Access Journals (Sweden)

S. Muster

2017-06-01

Full Text Available Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost Region Pond and Lake (PeRL database presents the results of a circum-Arctic effort to map ponds and lakes from modern (2002–2013 high-resolution aerial and satellite imagery with a resolution of 5 m or better. The database also includes historical imagery from 1948 to 1965 with a resolution of 6 m or better. PeRL includes 69 maps covering a wide range of environmental conditions from tundra to boreal regions and from continuous to discontinuous permafrost zones. Waterbody maps are linked to regional permafrost landscape maps which provide information on permafrost extent, ground ice volume, geology, and lithology. This paper describes waterbody classification and accuracy, and presents statistics of waterbody distribution for each site. Maps of permafrost landscapes in Alaska, Canada, and Russia are used to extrapolate waterbody statistics from the site level to regional landscape units. PeRL presents pond and lake estimates for a total area of 1. 4 × 106 km2 across the Arctic, about 17 % of the Arctic lowland ( <  300 m a.s.l. land surface area. PeRL waterbodies with sizes of 1. 0 × 106 m2 down to 1. 0 × 102 m2 contributed up to 21 % to the total water fraction. Waterbody density ranged from 1. 0 × 10 to 9. 4 × 101 km−2. Ponds are the dominant waterbody type by number in all landscapes representing 45–99 % of the total waterbody number. The implementation of PeRL size distributions in land surface models will greatly improve the investigation and projection of surface inundation and carbon fluxes in permafrost lowlands

Postglacial uplift of the eastern Gulf of Finland-Lake Ladoga region: models and observations

Science.gov (United States)

Amantov, Aleksey; Fjeldskaar, Willy; Amantova, Marina

2015-04-01

The eastern Gulf of Finland - Lake Ladoga region - is at the peripheral part of the Fennoscandian post-glacial uplift. We compared different modeling results for this region with observations, including our revision of geomorphological traces of paleo shorelevel. As in many parts of the general Baltic-White Sea bedrock lowland at the margin of the Fennoscandian Shield, the bedrock landscape was modified by glaciers, but it was also the major controlling factor for the history of glacial grows and decays. First-order landforms of this segment are: Lake Ladoga-Lake Ilmen lowland, Lembolovo High of the Karelic Isthmus and Neva-Gulf of Finland lowland. The range of the bedrock topography is close to 350 m. The landforms reflect different glacial behavior during stadials, with fast movement and strong erosion in northern Ladoga, but passive motion and accumulation around Lembolovo High. The differences influenced the ice sheet and deglaciation history. The shore level displacements in this area are slightly different than westwards in the Baltic area; the shoreline tilts are usually lower in southern-central part of the eastern Gulf of Finland-lake Ladoga region. For example, the shoreline tilts at 11 600 BP in the Baltic Ice Lake in the south-east range from 0.55 to 0.31 m/km. The slope of the Ancylus shoreline varies from 0.12 to 0.18 m/km, increasing to almost the double in the north-western area. Similarly, the Littorina shore level is tilted only 0.08 m/km, rising to 0.14 m/km in the north-west. We have used this data in our high resolution modeling involving glacial isostasy, hydro isostasy, sediment isostasy, and gravity field changes. The mopdeling is based on Earth rheology model with a low-viscosity asthenosphere of thickness less than 150 km and viscosity less than 7.0x10**19 Pa s above a mantle of viscosity 10**21 Pa s, and an effective elastic lithosphere thickness of 30-40 km (flexural rigidity 10**24 Nm). The specific uplift features in the area are

Yellowstone Lake Nanoarchaeota

Directory of Open Access Journals (Sweden)

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.

Hydraulic fracturing and the Crooked Lake Sequences: Insights gleaned from regional seismic networks

Science.gov (United States)

Schultz, Ryan; Stern, Virginia; Novakovic, Mark; Atkinson, Gail; Gu, Yu Jeffrey

2015-04-01

Within central Alberta, Canada, a new sequence of earthquakes has been recognized as of 1 December 2013 in a region of previous seismic quiescence near Crooked Lake, ~30 km west of the town of Fox Creek. We utilize a cross-correlation detection algorithm to detect more than 160 events to the end of 2014, which is temporally distinguished into five subsequences. This observation is corroborated by the uniqueness of waveforms clustered by subsequence. The Crooked Lake Sequences have come under scrutiny due to its strong temporal correlation (>99.99%) to the timing of hydraulic fracturing operations in the Duvernay Formation. We assert that individual subsequences are related to fracturing stimulation and, despite adverse initial station geometry, double-difference techniques allow us to spatially relate each cluster back to a unique horizontal well. Overall, we find that seismicity in the Crooked Lake Sequences is consistent with first-order observations of hydraulic fracturing induced seismicity.

Regional-scale analysis of lake outburst hazards in the southwestern Pamir, Tajikistan, based on remote sensing and GIS

Directory of Open Access Journals (Sweden)

M. Mergili

2011-05-01

Full Text Available This paper presents an analysis of the hazards emanating from the sudden drainage of alpine lakes in South-Western Tajik Pamir. In the last 40 yr, several new lakes have formed in the front of retreating glacier tongues, and existing lakes have grown. Other lakes are dammed by landslide deposits or older moraines. In 2002, sudden drainage of a glacial lake in the area triggered a catastrophic debris flow. Building on existing approaches, a rating scheme was devised allowing quick, regional-scale identification of potentially hazardous lakes and possible impact areas. This approach relies on GIS, remote sensing and empirical modelling, largely based on medium-resolution international datasets. Out of the 428 lakes mapped in the area, 6 were rated very hazardous and 34 hazardous. This classification was used for the selection of lakes requiring in-depth investigation. Selected cases are presented and discussed in order to understand the potentials and limitations of the approach used. Such an understanding is essential for the appropriate application of the methodology for risk mitigation purposes.

Local to regional scale industrial heavy metal pollution recorded in sediments of large freshwater lakes in central Europe (lakes Geneva and Lucerne) over the last centuries

Energy Technology Data Exchange (ETDEWEB)

Thevenon, Florian, E-mail: Florian.Thevenon@yahoo.fr [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland); Graham, Neil D. [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland); Chiaradia, Massimo [Department of Mineralogy, University of Geneva, Geneva (Switzerland); Arpagaus, Philippe; Wildi, Walter; Pote, John [Institute F.-A. Forel, University of Geneva, Versoix (Switzerland)

2011-12-15

This research first focuses on the spatial and temporal patterns of heavy metals from contrasting environments (highly polluted to deepwater sites) of Lake Geneva. The mercury (Hg) and lead (Pb) records from two deepwater sites show that the heavy metal variations before the industrial period are primarily linked to natural weathering input of trace elements. By opposition, the discharge of industrial treated wastewaters into Vidy Bay of Lake Geneva during the second part of the 20th century, involved the sedimentation of highly metal-contaminated sediments in the area surrounding the WWTP outlet pipe discharge. Eventually, a new Pb isotope record of sediments from Lake Lucerne identifies the long-term increasing anthropogenic lead pollution after ca. 1500, probably due to the development of metallurgical activities during the High Middle Ages. These data furthermore allows to compare the recent anthropogenic sources of water pollution from three of the largest freshwater lakes of Western Europe (lakes Geneva, Lucerne, and Constance). High increases in Pb and Hg highlight the regional impact of industrial pollution after ca. 1750-1850, and the decrease of metal pollution in the 1980s due to the effects of remediation strategies such as the implementation of wastewater treatment plants (WWTPs). However, at all the studied sites, the recent metal concentrations remain higher than pre-industrial levels. Moreover, the local scale pollution data reveal two highly contaminated sites (> 100 {mu}g Pb/g dry weight sediment) by industrial activities, during the late-19th and early-20th centuries (Lake Lucerne) and during the second part of the 20th century (Vidy Bay of Lake Geneva). Overall, the regional scale pollution history inferred from the three large and deep perialpine lakes points out at the pollution of water systems by heavy metals during the last two centuries due to the discharge of industrial effluents. Highlights: Black-Right-Pointing-Pointer Natural sources

Historical changes to Lake Washington and route of the Lake Washington Ship Canal, King County, Washington

Science.gov (United States)

Chrzastowski, Michael J.

1983-01-01

Lake Washington, in the midst of the greater Seattle metropolitan area of the Puget Sound region (fig. 1), is an exceptional commercial, recreational, and esthetic resource for the region . In the past 130 years, Lake Washington has been changed from a " wild " lake in a wilderness setting to a regulated lake surrounded by a growing metropolis--a transformation that provides an unusual opportunity to study changes to a lake's shoreline and hydrologic characteristics -resulting from urbanization.

Use of Satellite and In Situ Reflectance Data for Lake Water Color Characterization in the Everest Himalayan Region

Directory of Open Access Journals (Sweden)

Erica Matta

2017-02-01

Full Text Available This study applied remote sensing techniques to the study of water color in Himalayan glacial lakes as a proxy of suspended solid load. In situ measurements gathered in 5 lakes in October 2014 during satellite data acquisition enabled the characterization of water reflectance and clarity and supported image processing. Field data analysis led to a distinction between 3 water colors and a consequent lake water color classification on a regional scale from Landsat-8 data previously corrected for atmospheric and adjacency effects. Several morphometric parameters (lake size and shape, distance between lake and glacier were also computed for the lakes thus classified. The results showed spatial and temporal variations in lake water color, suggestive of relationships between glacier shrinkage and the presence of brighter and more turbid water. A finer-scale analysis of the spatial variability of water reflectance on Chola Lake (based on GeoEye-1 data captured on 18 October 2014 showed the contribution of water component absorption from the inflow. Overall, the findings support further research to monitor Himalayan lakes using both Landsat-8 and Sentinel-2 (with its improved resolutions.

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

Science.gov (United States)

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.

Great Lakes Restoration Initiative Great Lakes Mussel Watch(2009-2014)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Following the inception of the Great Lakes Restoration Initiative (GLRI) to address the significant environmental issues plaguing the Great Lakes region, the...

Sediment trace metal profiles in lakes of Killarney Park, Canada from regional to continental influence

International Nuclear Information System (INIS)

Belzile, Nelson; Chen Yuwei; Gunn, John M.; Dixit, Sushil S.

2004-01-01

The lakes in Killarney Provincial Park (KPP) located 40-60 km southwest of Sudbury, Ontario are beginning to recover after decades of being severely affected by acidification and atmospheric pollutants. Detailed profiles of acid-recoverable trace elements (As. Cd, Cu, Co. Fe, Mn, Ni, Pb and Zn) were obtained after aqua regia digestion and ICP-OES analysis of sediment cores taken from six Park lakes. Results permitted the identification of two types of profiles. The first type applies to elements such as Fe, Mn, As and Co for which historical deposition and recent recovery are strongly masked by diagenetic remobilization. The second type of profile applies to elements such as Cd, Cu, Ni, Pb and Zn on which the history of industrialisation in North America and mining activities in Sudbury can be superimposed. Based on sediment data of trace elements less affected by diagenetic remobilization (Cd, Cu, Ni, Pb, Zn), chemical recovery indices can be estimated from depth profiles. Indices of maximum (C p ) and surface (C s ) contamination were calculated by dividing the concentration of a given metal by the pre-industrial level. The ratio of the two indices provided a simple estimation of the chemical recovery of lakes that does not consider the influence of the watershed or the lake pH. Profiles of metals in sediment of KPP complement the water quality monitoring data and tend to indicate that this area is in transition from dominant influence of regional pollution sources to becoming controlled by continental atmospheric deposition. - Lakes in Killarney Park are in transition from being impacted by regional pollution to being controlled by continental atmospheric deposition

Remote sensing estimation of the total phosphorus concentration in a large lake using band combinations and regional multivariate statistical modeling techniques.

Science.gov (United States)

Gao, Yongnian; Gao, Junfeng; Yin, Hongbin; Liu, Chuansheng; Xia, Ting; Wang, Jing; Huang, Qi

2015-03-15

Remote sensing has been widely used for ater quality monitoring, but most of these monitoring studies have only focused on a few water quality variables, such as chlorophyll-a, turbidity, and total suspended solids, which have typically been considered optically active variables. Remote sensing presents a challenge in estimating the phosphorus concentration in water. The total phosphorus (TP) in lakes has been estimated from remotely sensed observations, primarily using the simple individual band ratio or their natural logarithm and the statistical regression method based on the field TP data and the spectral reflectance. In this study, we investigated the possibility of establishing a spatial modeling scheme to estimate the TP concentration of a large lake from multi-spectral satellite imagery using band combinations and regional multivariate statistical modeling techniques, and we tested the applicability of the spatial modeling scheme. The results showed that HJ-1A CCD multi-spectral satellite imagery can be used to estimate the TP concentration in a lake. The correlation and regression analysis showed a highly significant positive relationship between the TP concentration and certain remotely sensed combination variables. The proposed modeling scheme had a higher accuracy for the TP concentration estimation in the large lake compared with the traditional individual band ratio method and the whole-lake scale regression-modeling scheme. The TP concentration values showed a clear spatial variability and were high in western Lake Chaohu and relatively low in eastern Lake Chaohu. The northernmost portion, the northeastern coastal zone and the southeastern portion of western Lake Chaohu had the highest TP concentrations, and the other regions had the lowest TP concentration values, except for the coastal zone of eastern Lake Chaohu. These results strongly suggested that the proposed modeling scheme, i.e., the band combinations and the regional multivariate

Regional environment and hydrology changes documented by lake sediments from Lake Dalianhai, northeastern Tibetan Plateau since the last glacial maximum and their relationship with Asian summer monsoon variability

Science.gov (United States)

Wu, D.; Chen, F.; Zhou, A.; Abbott, M. B.

2016-12-01

Variability of the Asian summer monsoon (ASM) significantly affects environment and hydrology conditions within its area of influence, as well as economic and social development. Thus it is important to investigate the variability of the ASM on various time-scales and to explore its underlying forcing mechanisms, in order to improve our ability to predict the long-term trends of regional and global climate. Northeastern Tibetan Plateau, a margin area of modern ASM, is sensitive to summer monsoon changes. Existing paleoclimate records from this region contain conflicting evidence for the timing of summer monsoon advance into this region: an early arrival pre-Younger Dryas or a late arrival at the beginning of the Holocene. In addition, it is also debated that whether the Holocene ASM maximum in this region occurred during the early Holocene or the middle Holocene. Here we present a high-resolution record of a 52-m drilling core from Lake Dalianhai in this region. Multiply geochemistry indexes were obtained from the sediment core. 22 AMS 14C data from plant remains and bulk organic matters illustrate that the upper 52 m core covered the whole period since the last glacial maximum (LGM). The results generally indicate that the Lake Dalianhai was occupied by very shallow water body with eolian sand surrounding the lake from 20 to 15 ka BP (1ka=1000 cal yr). With the beginning of the B/A warm period, the sedimentary sequence changed to grey lacustrine clay abruptly. The sedimentary environment was relatively stable under a high lake level state during the B/A period which was marked with fine mean grain size, and high exogenous detrital element content (such as Al, K, Ti and Rb), but with low organic matter content. This perhaps was caused by the increasing of ASM precipitation. Increased contents of element Ca, Sr, and Br, as well as TOC and TN, highlight the increase of ASM during the Holocene. However, reddish lacustrine clay with lower magnetic susceptibility and

Occurrence and levels of glyphosate and AMPA in shallow lakes from the Pampean and Patagonian regions of Argentina.

Science.gov (United States)

Castro Berman, M; Marino, D J G; Quiroga, María Victoria; Zagarese, Horacio

2018-06-01

Glyphosate (N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide used to kill weeds that compete with commercial crops. In Argentina, the use of glyphosate-based herbicides increased dramatically (up to ∼200,000 tons on 2012) since the introduction of glyphosate-resistant crops, such as transgenic soy and resistant corn, and the adoption of non-till practices in the 1990's. Sallow lakes within the Pampa region may be potentially impacted by continuous herbicide usage. We surveyed 52 shallow lakes from the Pampa region (Buenos Aires Province, Argentina) to assess the occurrence and concentrations of glyphosate and its main degradation product (AMPA). For comparison, we also sampled 24 shallow lakes from an area with no agricultural use of glyphosate (Northern Patagonia). Glyphosate and AMPA were analyzed by UPLC-MS/MS ESI (±) in lake water, suspended particulate matter (SPM), and sediment samples. Within the Pampa region, glyphosate residues were detected in >40% of samples. Glyphosate residues were detected more frequently in sediment and surface water than in SPM samples. The mean (maximum) concentrations of glyphosate were 2.11 (4.52) μg l -1 for surface water; 0.10 (0.13) μg l -1 for SPM and 10.47 (20.34) μg kg -1 for sediment samples, respectively. Whereas, mean (maximum) concentrations of AMPA were 0.84 and (0.90) μg l -1 for surface water; 0.07 (0.07) μg l -1 for SPM; and 22.53 (32.89) μg kg -1 for sediment samples. The herbicide was not detected in samples from the Patagonian region. To our knowledge, this is the first study reporting the occurrence and concentrations of the herbicide in freshwater lakes of Argentina. Copyright © 2018 Elsevier Ltd. All rights reserved.

Position paper on renewable energies and nature protection in European lake regions

Energy Technology Data Exchange (ETDEWEB)

Anon.

2006-07-01

The man-made climate change is a central challenge of the lakes protection world wide in this century. By 2080, particularly in lake regions, the average temperature may rise - above all during the summer months - 2 to 5 degrees Celsius. Additionally, many regions will probably experience changes in rainfall (shift from summer to winter rainfalls) respectively declining rainfall in summer. These changes will have strong negative impacts on the people as well as on fauna and flora. The Solar Lakes Initiative is an approach of the Living Lakes-partners to tackle this vital problem. Focal points of this initiative are energy saving, energy efficiency and the use of renewable energies. The reason for this climate development is the growing discharge of greenhouse gases such as carbon dioxide and methane. Half of the man made greenhouse effect is due to CO2 emissions from energy supply. Therefore the international policy must aim at avoiding respectively clearly limiting any further temperature rise. An central contribution to solve this problem is the promotion and expansion of renewable energies. GNF calls for the implementation of the EU Guidelines on Renewable Energies determining a minimum share of 12% of clean energies in the total energy consumption by 2010. Additionally GNF supports the call of different environmental organisations and the EU Parliament for fixing a 25% target for renewable energies in the EU's overall energy consumption by 2020. GNF emphasises its attitude to support the nuclear power phase-out plans and its rejection to prolong the period of operation of the existing nuclear power plants in Germany. The governments in the EU should win over the interests of the energy industry and create basic conditions for the planned nuclear power phase-out. Legal regulations for power input rates such as the Renewable Energy Resources Act (EEG) have proved very useful. GNF supports the continuation and extension of the EEG in Germany to promote the

Environmental status of the Lake Michigan region. Volume 16. Amphibians and reptiles of the Lake Michigan drainage basin

Energy Technology Data Exchange (ETDEWEB)

Pentecost, E.D.; Vogt, R.C.

1976-07-01

The focus of this report is on regional distribution of the herpetofauna of the Lake Michigan Drainage Basin. The introduction includes a brief discussion of plant communities and their associated herpetofauna, and the importance of hibernacula and migration routes. Some aspects of the status, distribution, habitat, and life history of the amphibians and reptiles of the Basin are described in an annotated checklist. Special attention is given to uncommon and endangered species. Species range is shown on distribution maps.

Environmental status of the Lake Michigan region. Volume 16. Amphibians and reptiles of the Lake Michigan drainage basin

International Nuclear Information System (INIS)

Pentecost, E.D.; Vogt, R.C.

1976-07-01

The focus of this report is on regional distribution of the herpetofauna of the Lake Michigan Drainage Basin. The introduction includes a brief discussion of plant communities and their associated herpetofauna, and the importance of hibernacula and migration routes. Some aspects of the status, distribution, habitat, and life history of the amphibians and reptiles of the Basin are described in an annotated checklist. Special attention is given to uncommon and endangered species. Species range is shown on distribution maps

Climate Change in Africa: Impacts and Effects on the Inhabitants of the Lake Chad Region.

Science.gov (United States)

Abubakar, B.; Tahir, S. M.; Olisa, O.

2009-05-01

The Department of Energy and Climate Change defined climate as the average weather experienced over a long period. This includes temperature, wind and rainfall patterns. The climate of the Earth is not static, and has changed many times in response to a variety of natural causes. Due to human activities in emmiting green house gases has resulted the Earth to get warmed by 0.74°C over the last hundred years. Around 0.4°C of this warming has occurred since the 1970s. Climate is now one of the major phenomenon threatening lives and humanity in general since the beginning of industrial revolution. Climate exerts a profound influence on the lives of poor populations in the Lake Chad region of Africa who depend on fishing and crop cultivation for livelihood and sustenance, who are unprotected against climate-related diseases, who lacked secure access to water and food and who are vulnerable to hydro meteorological hazard. The effects of climate change on the study area are many and include diminishing resources and conflicts over the available limited water resources. The Lake Chad region is a fragile area with high climate variability and extremes of weather. As this inland water is used for domestic and agricultural purposes, salt mining, as well as transportation by Nigerians, Nigeriens, Chadian and Cameroonians, it is an area of trans-boundary water conflicts. This paper examines the part played by climate change in the decline of fishery resources and livelihood activities in the Lake Chad region. Data from field studies, structured interview and secondary sources show that fish catches and livelihood activities have declined tremendously in recent times due to several factors including overexploitation and increasing demands on the aquatic resources. Findings from the study show that droughty periods have resulted in the reduction of open lake water surface from about 25,000 km2 in 1973 to less than 2,000 km2 in the 1990s. This has led to the diminishing aquatic

Using Satellite Imagery to Monitor the Major Lakes; Case Study Lake Hamun

Science.gov (United States)

Norouzi, H.; Islam, R.; Bah, A.; AghaKouchak, A.

2015-12-01

Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes would provide invaluable information for policy-makers and local people. As part of a comprehensive study, we aim to monitor the land-cover/ land-use changes in the world's major lakes using satellite observations. As a case study, Hamun Lake which is a pluvial Lake, also known as shallow Lake, located on the south-east of Iran and adjacent to Afghanistan, and Pakistan borders is investigated. The Lake is the main source of resources (agriculture, fishing and hunting) for the people around it and politically important in the region since it is shared among three different countries. The purpose of the research is to find the Lake's area from 1972 to 2015 and to see if any drought or water resources management has affected the lake. Analyzing satellites imagery from Landsat shows that the area of the Lake changes seasonally and intra-annually. Significant seasonal effects are found in 1975,1977, 1987, 1993, 1996, 1998, 2000, 2009 and 2011, as well as, substantial amount of shallow water is found throughout the years. The precipitation records as well as drought historical records are studied for the lake's basin. Meteorological studies suggest that the drought, decrease of rainfalls in the province and the improper management of the Lake have caused environmental, economic and geographical consequences. The results reveal that lake has experienced at least two prolong dryings since 1972 which drought cannot solely be blamed as main forcing factor.Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes

Post-glacial recolonization of the Great Lakes region by the common gartersnake (Thamnophis sirtalis) inferred from mtDNA sequences.

Science.gov (United States)

Placyk, John S; Burghardt, Gordon M; Small, Randall L; King, Richard B; Casper, Gary S; Robinson, Jace W

2007-05-01

Pleistocene events played an important role in the differentiation of North American vertebrate populations. Michigan, in particular, and the Great Lakes region, in general, were greatly influenced by the last glaciation. While several hypotheses regarding the recolonization of this region have been advanced, none have been strongly supported. We generated 148 complete ND2 mitochondrial DNA (mtDNA) sequences from common gartersnake (Thamnophis sirtalis) populations throughout the Great Lakes region to evaluate phylogeographic patterns and population structure and to determine whether the distribution of haplotypic variants is related to the post-Pleistocene retreat of the Wisconsinan glacier. The common gartersnake was utilized, as it is believed to have been one of the primary vertebrate invaders of the Great Lakes region following the most recent period of glacial retreat and because it has been a model species for a variety of evolutionary, ecological, behavioral, and physiological studies. Several genetically distinct evolutionary lineages were supported by both genealogical and molecular population genetic analyses, although to different degrees. The geographic distribution of the majority of these lineages is interpreted as reflecting post-glacial recolonization dynamics during the late Pleistocene. These findings generally support previous hypotheses of range expansion in this region.

Environmental status of the Lake Michigan region. Volume 6. Zoobenthos of Lake Michigan

Energy Technology Data Exchange (ETDEWEB)

Mozley, S.C.; Howmiller, R.P.

1977-09-01

This report summarizes Lake Michigan zoobenthic studies up to 1974, including reports of power-plant surveys. It describes ecologies of macroinvertebrate species and some microfauna, partly through use of data from other Great Lakes. The following are discussed: methodology of field surveys; zoobenthic indicators of pollution; zoobenthic effects on sediment-water exchanges; and numbers, biomass, and production of total macroinvertebrates. Prominent features of Lake Michigan zoobenthos include predominance of the amphipod Pontoporeia affinis, usefulness of tubificid oligochaetes in mapping environmental quality, and pronounced qualitative gradients in zoobenthos in relation to depth. Further research is needed on sampling methods, energy flow rates and pathways through benthic communities, factors limiting distribution of species near shore, and effects of macroinvertebrates on sediment chemistry and structure.

Evaluation of Water Quality Change of Brackish Lake in Snowy Cold Regions Accompanying Climate Change

Science.gov (United States)

Kudo, K.; Hasegawa, H.; Nakatsugawa, M.

2017-12-01

This study addresses evaluation of water quality change of brackish lake based on the estimation of hydrological quantities resulting from long-term hydrologic process accompanying climate change. For brackish lakes, such as Lake Abashiri in Eastern Hokkaido, there are concerns about water quality deterioration due to increases in water temperature and salinity. For estimating some hydrological quantities in the Abashiri River basin, including Lake Abashiri, we propose the following methods: 1) MRI-NHRCM20, a regional climate model based on the Representative Concentration Pathways adopted by IPCC AR5, 2) generalized extreme value distribution for correcting bias, 3) kriging adopted variogram for downscaling and 4) Long term Hydrologic Assessment model considering Snow process (LoHAS). In addition, we calculate the discharge from Abashiri River into Lake Abashiri by using estimated hydrological quantities and a tank model, and simulate impacts on water quality of Lake Abashiri due to climate change by setting necessary conditions, including the initial conditions of water temperature and water quality, the pollution load from the inflow rivers, the duration of ice cover and salt pale boundary. The result of the simulation of water quality indicates that climate change is expected to raise the water temperature of the lake surface by approximately 4°C and increase salinity of surface of the lake by approximately 4psu, also if salt pale boundary in the lake raises by approximately 2-m, the concentration of COD, T-N and T-P in the bottom of the lake might increase. The processes leading to these results are likely to be as follows: increased river water flows in along salt pale boundary in lake, causing dynamic flow of surface water; saline bottom water is entrained upward, where it mixes with surface water; and the shear force acting at salt pale boundary helps to increase the supply of salts from bottom saline water to the surface water. In the future, we will

Cooperation control strategies for China's cross-region pollution in a lake basin based on green reduction cost.

Science.gov (United States)

Li, Changmin; Sun, Dong; Xie, Xiaoqiang; Xue, Jian

2016-05-01

The cross-region water pollution issue has always been the widespread concern around the world. It becomes especially critical for China due to the imbalance relates to environmental costs that have accompanied rapid growth of economy. Though the government makes great efforts to improve it, the potential for water pollution conflict is still great. We consider the problem of determining combined control strategies for China's cross-region lake pollution based on the environmental green costs. The problem is first formulated as a generalized bilevel mathematical program where the upper level consists in each region that reduces environmental green costs including three parts: the reduction cost, pollution permit trade cost and cost of environment damage, while the lower level is represented by pollution permit equilibrium market. Finally, we take an empirical analysis in Taihu lake. The numerical study shows that the minimum costs of both total and regional are obviously superior to the current processing costs, which provides theoretical basis for the price of emission permits. Today, China's rapid gross domestic product (GDP) growth has come at a very high cost, as real estate prices have skyrocketed, the wealth gap has widened, and environmental pollution has worsened. China's central government is urged to correct the GDP-oriented performance evaluation system that is used to judge administrative region leaders. The cross-region water pollution issue has become a troubling issue that urgently needs to be resolved in China. This paper will not only actively aid efforts to govern Lake Taihu and other cross-region valleys, but it will also provide a supplement for theoretical research on cross-region pollution issues.

Lake Morphometry for NHD Lakes in the Upper Portion of the Missouri Region 10 HUC

Data.gov (United States)

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...

Lake Morphometry for NHD Lakes in the Lower Portion of the Missouri Region 10 HUC

Data.gov (United States)

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...

A synthesis of thermokarst lake water balance in high-latitude regions of North America from isotope tracers

Science.gov (United States)

MacDonald, Lauren A.; Wolfe, Brent B.; Turner, Kevin W.; Anderson, Lesleigh; Arp, Christopher D.; Birks, Jean; Bouchard, Frédéric; Edwards, Thomas W.D.; Farquharson, Nicole; Hall, Roland I.; McDonald, Ian; Narancic, Biljana; Ouimet, Chantal; Pienitz, Reinhard; Tondu, Jana; White, Hilary

2017-01-01

Numerous studies utilizing remote sensing imagery and other methods have documented that thermokarst lakes are undergoing varied hydrological transitions in response to recent climate changes, from surface area expansion to drainage and evaporative desiccation. Here, we provide a synthesis of hydrological conditions for 376 lakes of mainly thermokarst origin across high-latitude North America. We assemble surface water isotope compositions measured during the past decade at five lake-rich landscapes including Arctic Coastal Plain (Alaska), Yukon Flats (Alaska), Old Crow Flats (Yukon), northwestern Hudson Bay Lowlands (Manitoba), and Nunavik (Quebec). These landscapes represent the broad range of thermokarst environments by spanning gradients in meteorological, permafrost, and vegetation conditions. An isotope framework was established based on flux-weighted long-term averages of meteorological conditions for each lake to quantify water balance metrics. The isotope composition of source water and evaporation-to-inflow ratio for each lake were determined, and the results demonstrated a substantial array of regional and subregional diversity of lake hydrological conditions. Controls on lake water balance and how these vary among the five landscapes and with differing environmental drivers are assessed. Findings reveal that lakes in the Hudson Bay Lowlands are most vulnerable to evaporative desiccation, whereas those in Nunavik are most resilient. However, we also identify the complexity in predicting hydrological responses of these thermokarst landscapes to future climate change.

Use of wetlands for water quality improvement under the USEPA Region V Clean Lakes Program

Science.gov (United States)

Landers, Judith C.; Knuth, Barbara A.

1991-03-01

The United States Environmental Protection Agency (USEPA) Region V Clean Lakes Program employs artificial and modified natural wetlands in an effort to improve the water quality of selected lakes. We examined use of wetlands at seven lake sites and evaluated the physical and institutional means by which wetland projects are implemented and managed, relative to USEPA program goals and expert recommendations on the use of wetlands for water quality improvement. Management practices recommended by wetlands experts addressed water level and retention, sheet flow, nutrient removal, chemical treatment, ecological and effectiveness monitoring, and resource enhancement. Institutional characteristics recommended included local monitoring, regulation, and enforcement and shared responsibilities among jurisdictions. Institutional and ecological objectives of the National Clean Lakes Program were met to some degree at every site. Social objectives were achieved to a lesser extent. Wetland protection mechanisms and appropriate institutional decentralization were present at all sites. Optimal management techniques were employed to varying degrees at each site, but most projects lack adequate monitoring to determine adverse ecological impacts and effectiveness of pollutant removal and do not extensively address needs for recreation and wildlife habitat. There is evidence that the wetland projects are contributing to improved lake water quality; however, more emphasis needs to be placed on wetland protection and long-term project evaluation.

Variability in methane emissions from West Siberia's shallow boreal lakes on a regional scale and its environmental controls

Directory of Open Access Journals (Sweden)

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.

Huguangyan Maar Lake (SE China): A solid record of atmospheric mercury pollution history in a non-remote region

Science.gov (United States)

Zeng, Yan; Chen, Jingan; Yang, Yongqiong; Wang, Jianxu; Zhu, Zhengjie; Li, Jian

2017-10-01

Mercury is a highly toxic metal that can cause harm to environment and human health. As atmospheric deposition is the main source of total Hg input to aquatic system in remote and pristine regions, almost all the studies on atmospheric Hg pollution history concentrated in these areas, while the studies in non-remote areas are much limited, especially for the long history records. In this study, Huguangyan Maar Lake, an undisturbed lake system at low altitude in China, was selected to reconstruct the atmospheric mercury pollution history. Variation patterns of TOC, Hg and non-residual Sr in the sediment core indicated that, compared to the direct atmospheric Hg deposition, the effect of either Hg scavenging from water column by algae or the catchment inputs of previously deposited Hg on the Hg accumulation in the lake sediment was limited. The sediment Hg content in Huguangyan Lake was mainly controlled by the atmospheric Hg deposition, and thus accurately reflected the atmospheric Hg pollution history. The Hga (Hg content from atmospheric deposition) in Huguangyan Lake presented a comparable variation pattern to that in remote sites. It had the same variation trend as the global atmospheric Hg before 1950 CE, which could be attributed to the Industrial Revolution. After that, it was mainly controlled by Hg emissions from Asian countries. The variation of Hga also indicated that atmospheric Hg deposition accelerated significantly since 2000 CE. This study, along with other investigations in remote sites in China, showed that the sediment Hg in Huguangyan Lake responded to the atmospheric Hg pollution more sensitively than in the alpine regions. It should be noted that, the more intensive acceleration of Hg deposition in Huguangyan Lake may imply that the South of China suffered from much more serious atmospheric Hg pollution than previous studies revealed.

Modelling regional response of lakewater chemistry to changes in acidic deposition: the MAGIC model applied to lake surveys in southernmost Norway 1974-1986-1995

Directory of Open Access Journals (Sweden)

B. J. Cosby

1998-01-01

Full Text Available Two methods for modelling regional responses of lake water quality to changes in acidic deposition in southernmost Norway were examined. Both methods are based upon the MAGIC model but differ in mode of regional application; one uses site-specific while the other uses Monte-Carlo methods for model calibration. The simulations of regional responses from both methods were compared with observed responses based on data from three lake surveys in southernmost Norway conducted in 1974, 1986 and 1995. The regional responses of the two modelling approaches were quite similar and agreed well with the observed regional distributions of lakewater chemistry variables. From 1974 to 1986 the observed data indicated that despite a decline of approximately 10% in sulphate (SO4 deposition, the mean acid neutralizing capacity (ANC of lakes in southernmost Norway declined by approximately 6 μeq l-1. Both modelling approaches simulated no change or a very small decline in mean ANC for that period. From 1986 to 1995 the observed data indicated that, in response to an approximate 40% decline in SO4 deposition, the mean ANC of lakes in southernmost Norway increased by 11-16 μeq l-1. The modelling approaches simulated increases of 9-10 μeq l-1 in mean ANC for the same period. Both simulations and observations indicate that > 65% of lakes in southernmost Norway were acidic in 1974 and 1995. Both simulation methods predict that >65% of the lakes in southernmost Norway will have positive ANC values within 10 years of reductions of SO4 deposition to 20% of 1974 levels. Of the two regionalization methods the site-specific method appears preferable, because whereas the Monte-Carlo method gives results for a region as a whole, the site-specific method also reveals patterns within the region. The maintenance of a one-to-one correspondence between simulated and observed systems means that simulation results can be mapped for a geographically explicit presentation of model

Global Lakes Sentinel Services: Evaluation of Chl-a Trends in Deep Clear Lakes

Science.gov (United States)

Cazzaniga, Ilaria; Giardino, Claudia; Bresciani, Mariano; Poser, Kathrin; Peters, Steef; Hommersom, Annelies; Schenk, Karin; Heege, Thomas; Philipson, Petra; Ruescas, Ana; Bottcher, Martin; Stelzer, Kerstin

2016-08-01

The aim of this study is the analysis of trend in the trophic level evolution in clear deep lakes which, being characterised by good quality state, are important socio- economic resources for their regions. The selected lakes are situated in Europe (Garda, Maggiore, Constance and Vättern), North America (Michigan) and Africa (Malawi and Tanganyika) and cover a range of eco- regions (continental, perialpine, boreal, rift valley) distributed globally.To evaluate trophic level tendency we mainly focused on chlorophyll-a concentrations (chl-a) which is a direct proxy of trophic status. The chl-a concentrations were obtained from 5216 cloud-free MERIS imagery from 2002 to 2012.The 'GLaSS RoIStats tool' available within the GLaSS project was used to extract chl-a in a number of region of interests (ROI) located in pelagic waters as well as some few other stations depending on lakes morphology. For producing the time-series trend, these extracted data were analysed with the Seasonal Kendall test.The results overall show almost stable conditions with a slight increase in concentration for lakes Maggiore, Constance, and the Green Bay of Lake Michigan; a slight decrease for lakes Garda and Tanganyika and absolutely stable conditions for lakes Vättern and Malawi.The results presented in this work show the great capability of MERIS to perform trend tests analysis on trophic status with focus on chl-a concentration. Being chl-a also a key parameter in water quality monitoring plans, this study also supports the managing practices implemented worldwide for using the water of the lakes.

Sanctuaries for lake trout in the Great Lakes

Science.gov (United States)

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

1987-01-01

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

Glacial lakes of the Central and Patagonian Andes

Science.gov (United States)

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.

Microbiology of Lonar Lake and other soda lakes

Science.gov (United States)

Paul Antony, Chakkiath; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

2013-01-01

Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

Development of a Regional Glycerol Dialkyl Glycerol Tetraether (GDGT) - Temperature Calibration for Antarctic and sub-Antarctic Lakes

Science.gov (United States)

Roberts, S. J.; Foster, L. C.; Pearson, E. J.; Steve, J.; Hodgson, D.; Saunders, K. M.; Verleyen, E.

2016-12-01

Temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have been used to reconstruct past temperatures in both marine and terrestrial environments, but have not been widely applied in high latitude environments. This is mainly because the performance of GDGT-temperature calibrations at lower temperatures and GDGT provenance in many lacustrine settings remains uncertain. To address these issues, we examined surface sediments from 32 Antarctic, sub-Antarctic and Southern Chilean lakes. First, we quantified GDGT compositions present and then investigated modern-day environmental controls on GDGT composition. GDGTs were found in all 32 lakes studied. Branched GDGTs (brGDGTs) were dominant in 31 lakes and statistical analyses showed that their composition was strongly correlated with mean summer air temperature (MSAT) rather than pH, conductivity or water depth. Second, we developed the first regional brGDGT-temperature calibration for Antarctic and sub-Antarctic lakes based on four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). Of these, GDGT-IIIb proved particularly important in cold lacustrine environments. Our brGDGT-Antarctic temperature calibration dataset has an improved statistical performance at low temperatures compared to previous global calibrations (r2=0.83, RMSE=1.45°C, RMSEP-LOO=1.68°C, n=36 samples), highlighting the importance of basing palaeotemperature reconstructions on regional GDGT-temperature calibrations, especially if specific compounds lead to improved model performance. Finally, we applied the new Antarctic brGDGT-temperature calibration to two key lake records from the Antarctic Peninsula and South Georgia. In both, downcore temperature reconstructions show similarities to known Holocene warm periods, providing proof of concept for the new Antarctic calibration model.

EVALUATING REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL, REGIONAL-MERCURY CYCLING MODEL (R-MCM), APPLIED TO 91 VERMONT AND NEW HAMPSHIRE LAKES AND PONDS, USA

Science.gov (United States)

Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The Regional Mercury Cycling model (R-MCM) was specifically d...

Using multi-year reanalysis-derived recharge rates to drive a groundwater model for the Lake Tana region of Blue Nile Basin, Ethiopia

Science.gov (United States)

Dokou, Z.; Kheirabadi, M.; Nikolopoulos, E. I.; Moges, S. A.; Bagtzoglou, A. C.; Anagnostou, E. N.

2017-12-01

Ethiopia's high inter-annual variability in local precipitation has resulted in droughts and floods that stress local communities and lead to economic and food insecurity. Better predictions of water availability can supply farmers and water management authorities with critical guidance, enabling informed water resource allocation and management decisions that will in turn ensure food and water security in the region. The work presented here focuses on the development and calibration of a groundwater model of the Lake Tana region, one of the most important sub-basins of the Blue Nile River Basin. Groundwater recharge, which is the major groundwater source in the area, depends mainly on the seasonality of precipitation and the spatial variation in geology. Given that land based precipitation data are sparse in the region, two approaches for estimating groundwater recharge were used and compared that both utilize global atmospheric reanalysis driven by remote sensing datasets. In the first approach, the reanalysis precipitation dataset (ECMWF reanalysis adjusted based on GPCC) together with evapotranspiration and surface run-off estimates are used to calculate the groundwater recharge component using water budget equations. In the second approach, groundwater recharge estimates (subsurface runoff) are taken directly from a Land Surface model (FLDAS Noah), provided at a monthly time scale and 0.1˚ x 0.1˚ spatial resolution. The reanalysis derived recharge rates in both cases are incorporated into the groundwater model MODFLOW, which in combination with a Lake module that simulates the Lake water budget, offers a unique capability of improving the predictability of groundwater and lake levels in the Lake Tana basin. Model simulations using the two approaches are compared against in-situ observations of groundwater and lake levels. This modeling effort can be further used to explore climate variability effects on groundwater and lake levels and provide guidance to

Hazards of volcanic lakes: analysis of Lakes Quilotoa and Cuicocha, Ecuador

Directory of Open Access Journals (Sweden)

G. Gunkel

2008-01-01

Full Text Available Volcanic lakes within calderas should be viewed as high-risk systems, and an intensive lake monitoring must be carried out to evaluate the hazard of potential limnic or phreatic-magmatic eruptions. In Ecuador, two caldera lakes – Lakes Quilotoa and Cuicocha, located in the high Andean region >3000 a.s.l. – have been the focus of these investigations. Both volcanoes are geologically young or historically active, and have formed large and deep calderas with lakes of 2 to 3 km in diameter, and 248 and 148 m in depth, respectively. In both lakes, visible gas emissions of CO₂ occur, and an accumulation of CO₂ in the deep water body must be taken into account.

Investigations were carried out to evaluate the hazards of these volcanic lakes, and in Lake Cuicocha intensive monitoring was carried out for the evaluation of possible renewed volcanic activities. At Lake Quilotoa, a limnic eruption and diffuse CO₂ degassing at the lake surface are to be expected, while at Lake Cuicocha, an increased risk of a phreatic-magmatic eruption exists.

Predicting Maximum Lake Depth from Surrounding Topography

Science.gov (United States)

Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

Analysis of long-term forest bird monitoring data from national forests of the western Great Lakes Region

Science.gov (United States)

Gerald J. Niemi; Robert W. Howe; Brian R. Sturtevant; Linda R. Parker; Alexis R. Grinde; Nicholas P. Danz; Mark D. Nelson; Edmund J. Zlonis; Nicholas G. Walton; Erin E. Gnass Giese; Sue M. Lietz

2016-01-01

Breeding bird communities in forests of the western Great Lakes region are among the most diverse in North America, but the forest environment in this region has changed dramatically during the past 150 years. To address concerns about loss of biodiversity due to ongoing forest harvesting and to better inform forest planning, researchers have systematically monitored...

Post-War Economics. Micro-Level Evidence from the African Great Lakes Region

OpenAIRE

D'Aoust, Olivia

2015-01-01

This thesis starts by arguing that the civil conflicts that erupted in the African Great Lakes are rooted in a continuous pursuit of power, in which ethnic, regional and political identifiers are used by the contenders for power to rally community support. In an introductory chapter, I go back to the colonial era, drawing attention to Burundi and Rwanda, and then describe in more details Burundi's refugee crisis, ex-combatants' demobilization and the 2010 elections, all of which will be addre...

Deglaciation, lake levels, and meltwater discharge in the Lake Michigan basin

Science.gov (United States)

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

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

Data.gov (United States)

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...

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

Data.gov (United States)

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...

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

Data.gov (United States)

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...

Evolution of alkaline lakes - Lake Van case study

Science.gov (United States)

Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

2017-04-01

Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this

Energy and water in the Great Lakes.

Energy Technology Data Exchange (ETDEWEB)

Tidwell, Vincent Carroll

2011-11-01

The nexus between thermoelectric power production and water use is not uniform across the U.S., but rather differs according to regional physiography, demography, power plant fleet composition, and the transmission network. That is, in some regions water demand for thermoelectric production is relatively small while in other regions it represents the dominate use. The later is the case for the Great Lakes region, which has important implications for the water resources and aquatic ecology of the Great Lakes watershed. This is today, but what about the future? Projected demographic trends, shifting lifestyles, and economic growth coupled with the threat of global climate change and mounting pressure for greater U.S. energy security could have profound effects on the region's energy future. Planning for such an uncertain future is further complicated by the fact that energy and environmental planning and regulatory decisionmaking is largely bifurcated in the region, with environmental and water resource concerns generally taken into account after new energy facilities and technologies have been proposed, or practices are already in place. Based on these confounding needs, the objective of this effort is to develop Great Lakes-specific methods and tools to integrate energy and water resource planning and thereby support the dual goals of smarter energy planning and development, and protection of Great Lakes water resources. Guiding policies for this planning are the Great Lakes and St. Lawrence River Basin Water Resources Compact and the Great Lakes Water Quality Agreement. The desired outcome of integrated energy-water-aquatic resource planning is a more sustainable regional energy mix for the Great Lakes basin ecosystem.

Spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region (Alberta, Canada)

Science.gov (United States)

Cooke, Colin A.; Kirk, Jane L.; Muir, Derek C. G.; Wiklund, Johan A.; Wang, Xiaowa; Gleason, Amber; Evans, Marlene S.

2017-12-01

The mining and processing of the Athabasca oil sands (Alberta, Canada) has been occurring for decades; however, a lack of consistent regional monitoring has obscured the long-term environmental impact. Here, we present sediment core results to reconstruct spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region. Early mining operations (during the 1970s and 1980s) led to elevated V and Pb inputs to lakes located quality guidelines, and no spatial or temporal trends were observed in the frequency of guideline exceedence. Our results demonstrate that early mining efforts had an even greater impact on trace element cycling than has been appreciated previously, placing recent monitoring efforts in a critical long-term context.

Predicting the locations of naturally fishless lakes

Science.gov (United States)

Schilling, Emily Gaenzle; Loftin, C.S.; Degoosh, K.E.; Huryn, Alexander D.; Webster, K.E.

2008-01-01

1. Fish have been introduced into many previously fishless lakes throughout North America over the past 100+ years. It is difficult to determine the historical distribution of fishless lakes, however, because these introductions have not always been well-documented. 2. Due to its glacial history and low human population density, the state of Maine (U.S.A.) may host the greatest number of naturally fishless lakes in the northeastern United States. However, less than one-quarter of Maine's 6000+ lakes have been surveyed for fish presence, and no accurate assessments of either the historical or current abundance and distribution of fishless lakes exist. 3. We developed methods to assess the abundance and distribution of Maine's naturally fishless lakes (0.6-10.1 ha). We hypothesized that the historical distribution of fishless lakes across a landscape is controlled by geomorphic and geographic conditions. 4. We used ArcGIS to identify landscape-scale geomorphic and geographic factors (e.g. connectivity, surrounding slope) correlated with fish absence in two geomorphic regions of Maine - the western and interior mountains and the eastern lowlands and foothills. By using readily available geographic information systems data our method was not limited to field-visited sites. We estimated the likelihood that a particular lake is fishless with a stepwise logistic regression model developed for each region. 5. The absence of fish from western lakes is related to altitude (+), minimum percent slope in the 500 m buffer (+), maximum percent slope in the 500 m buffer (+) and percent cover of herbaceous-emergent wetland in 1000 m buffer (-). The absence of fish from eastern lakes is related to the lack of a stream within 50 m of the lake. 6. The models predict that a total of 4% (131) of study lakes in the two regions were historically fishless, with the eastern region hosting a greater proportion than the western region. 7. We verified the model predictions with two

Applications of the Regional Atmospheric Modeling System (RAMS) to provide input to photochemical grid models for the Lake Michigan Ozone Study (LMOS)

Energy Technology Data Exchange (ETDEWEB)

Lyons, W.A.; Tremback, C.J.; Pielke, R.A. [ASTeR, Inc., Ft. Collins, CO (United States); Eastman, J.L. [Colorado State Univ., Ft. Collins, CO (United States)

1994-12-31

In spite of stringent emission controls, numerous exceedances of the US ozone air quality standard have continued in the Lake Michigan region, especially during the very hot summers of 1987 and 1988. Analyses revealed that exceedances of the 120 PPB hourly standard were 400% more likely at monitors located within 20 km of the lakeshore. While the role of Lake Michigan in exacerbating regional air quality problems has been investigated for almost 20 years, the relative impacts of various phenomena upon regional photochemical air quality have yet to be quantified. In order to design a defensible regional emission control policy, LMOS sponsored the development of a comprehensive regional photochemical modeling system. This is comprised of an emission model, an advanced regional photochemical model, and a prognostic meteorological model.

Investigation of the dispersion of airborne pollutants in the Upper Rhine and Lake Constance region

International Nuclear Information System (INIS)

Fiedler, F.; Adrian, G.; Kohler, M.

1991-01-01

The aim of the project is to calculate the regional flow and propagation conditions using the expensive three-dimensional meteorological model, the ''Karlsruher Atmosphaerisches Mesoskaliges Modell'' (KAMM) in order to derive the immission and the deposition of the conducting substance of pollutant matter, i.e., sulphur dioxide. In this report, calculations of the flowing field are described for the region Upper Rhine - Lake of Constance''. In the last part, the concentration fields for SO 2 are calculated for the region for typical large-area atmospheric conditions with disclosure of sources. An appraising discussion of the results concludes this work. (orig.) [de

U.S. Forest Service Region 1 Lake Chemistry, NADP, and IMPROVE air quality data analysis

Science.gov (United States)

Jill Grenon; Mark Story

2009-01-01

This report was developed to address the need for comprehensive analysis of U.S. Forest Service (USFS) Region 1 air quality monitoring data. The monitoring data includes Phase 3 (long-term data) lakes, National Atmospheric Deposition Program (NADP), and Interagency Monitoring of Protected Visual Environments (IMPROVE). Annual and seasonal data for the periods of record...

Regional environmental change and human activity over the past hundred years recorded in the sedimentary record of Lake Qinghai, China.

Science.gov (United States)

Sha, ZhanJiang; Wang, Qiugui; Wang, Jinlong; Du, Jinzhou; Hu, Jufang; Ma, Yujun; Kong, Fancui; Wang, Zhuan

2017-04-01

Environmental change and human activity can be recorded in sediment cores in aquatic systems such as lakes. Information from such records may be useful for environmental governance in the future. Six sediment cores were collected from Lake Qinghai, China and its sublakes during 2012 and 2013. Measurements of sediment grain-size fractions indicate that sedimentation in the north and southwest of Lake Qinghai is dominated by river input, whereas that in Lake Gahai and Lake Erhai is dominated by dunes. The sedimentation rates in Lake Qinghai were calculated to be 0.101-0.159 cm/y, similar to the rates in other lakes on the Qinghai-Tibetan Plateau. Using these data and sedimentation rates from the literature, we compiled the spatial distribution of sedimentation rates. Higher values were obtained in the three main areas of Lake Qinghai: two in river estuaries and one close to sand dunes. Lower values were measured in the center and south of the lake. Measurements of total organic carbon (TOC), total nitrogen (TN), phosphorus concentrations, and TOC/TN ratios in three cores (QH01, QH02, and Z04) revealed four horizons corresponding to times of increased human activity. These anthropogenic events were (1) the development of large areas of cropland in the Lake Qinghai watershed in 1960, (2) the beginning of nationwide fertilizer use and increases in cropland area in the lake watershed after 1970, (3) the implementation of the national program "Grain to Green," and (4) the rapid increase in the tourism industry from 2000. Profiles of Rb, Sr concentrations, the Rb/Sr ratio, and grain-size fraction in core Z04 indicate that the climate has become drier over the past 100 years. Therefore, we suggest that lake sediments such as those in Lake Qinghai are useful media for high-resolution studies of regional environmental change and human activity.

Climate and climate variability of the wind power resources in the Great Lakes region of the United States

Science.gov (United States)

X. Li; S. Zhong; X. Bian; W.E. Heilman

2010-01-01

The climate and climate variability of low-level winds over the Great Lakes region of the United States is examined using 30 year (1979-2008) wind records from the recently released North American Regional Reanalysis (NARR), a three-dimensional, high-spatial and temporal resolution, and dynamically consistent climate data set. The analyses focus on spatial distribution...

Resilience and Restoration of Lakes

Directory of Open Access Journals (Sweden)

Stephen R. Carpenter

1997-06-01

Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

Sustainable management of lakes in connection with mitigation of adverse effects of climate change, agriculture and development of green micro regions based on renewable energy production

Directory of Open Access Journals (Sweden)

Sandor Antal Nemethy

2014-11-01

Full Text Available Lake management is extremely complex and requires a coordinated effort of research institutions, community groups, individuals, landowners, and government. Lakes constitute an important group of natural resources due to their ecosystem services and often unique cultural environments. Climate change is a growing concern, which particularly strongly affects shallow lakes. The adverse impact of climate change is enhanced by extreme water level fluctuations and human factors such as environmental pollution from waste water discharge, large scale agriculture and shoreline constructions reducing or eliminating valuable wetlands. Since eutrophication is a leading cause of impairment of freshwater ecosystems, specific strategies to address a lake's nutrient enrichment must focus on activities in the watershed and, if needed, in-lake restoration techniques. Analyzing the key factors of sustainable local and regional development in the vicinity of lakes, assessing the environmental risks of pollution, large scale agriculture, waste management and energy production, we propose a complex, stakeholder based management system and holistic regional development in lake areas, which will preserve natural ecosystems without compromising the sustainable use of ecosystem services. There are available technologies to develop ecologically acceptable water level regulations, promote organic agriculture applying grey water irrigation, stop leachate from landfills and control invasive species. Regional and local production and use of renewable energy is essential both for environmental and economical sustainability. Renewable energy production should be well coordinated with agriculture, forestry, waste management and management of water resources of lakes and their watershed areas in a sustainable, holistic way through a participatory approach. This is particularly pronounced in connection with tourism as one of the main uses of lake-ecosystem services, but also an

L-Lake macroinvertebrate community

International Nuclear Information System (INIS)

Specht, W.L.

1996-06-01

To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

L-Lake macroinvertebrate community

Energy Technology Data Exchange (ETDEWEB)

Specht, W.L.

1996-06-01

To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

Directory of Open Access Journals (Sweden)

Gerhard MAIER

2005-08-01

reproduction of zooplanktivorous European whitefish, Coregonus lavaretus, which feeds highly selectively on large cladocerans and which is of great economic significance for the whole region. Another possibility could be that the lack of large Cladocera in the Lower Lake is a result of strong fish predation which could be a consequence of lake morphology.

The PIRLA project: paleoecological investigations of recent lake acidification

Energy Technology Data Exchange (ETDEWEB)

Charles, D F; Whitehead, D R

1986-12-19

The PIRLA project is a broadly interdisciplinary paleolimnological investigation of five to fifteen comparable watershed lake systems from each of four low-alkalinity regions in North America that are currently receiving acid deposition. The areas are the Adirondack Mountains (N.Y.), northern New England, northern Great Lakes states, and northern Florida. The primary objective of the study is to provide a detailed reconstruction of the recent acidification histories of a representative suite of lakes from each of the regions. The study will increase our understanding of the timing, rates, and magnitude of acidification (and other chemical changes), and the regional and inter-regional patterns of lake acidification. 3 figs., 2 tabs., 41 refs.

The predominance of young carbon in Arctic whole-lake CH4 and CO2 emissions and implications for Boreal yedoma lakes.

Science.gov (United States)

Elder, C.; Xu, X.; Walker, J. C.; Walter Anthony, K. M.; Pohlman, J.; Arp, C. D.; Townsend-Small, A.; Hinkel, K. M.; Czimczik, C. I.

2017-12-01

Lakes in Arctic and Boreal regions are hotspots for atmospheric exchange of the greenhouse gases CO2 and CH4. Thermokarst lakes are a subset of these Northern lakes that may further accelerate climate warming by mobilizing ancient permafrost C (> 11,500 years old) that has been disconnected from the active C cycle for millennia. Northern lakes are thus potentially powerful agents of the permafrost C-climate feedback. While they are critical for projecting the magnitude and timing these feedbacks from the rapidly warming circumpolar region, we lack datasets capturing the diversity of northern lakes, especially regarding their CH4contributions to whole-lake C emissions and their ability to access and mobilize ancient C. We measured the radiocarbon (14C) ages of CH4 and CO2 emitted from 60 understudied lakes and ponds in Arctic and Boreal Alaska during winter and summer to estimate the ages of the C sources yielding these gases. Integrated mean ages for whole-lake emissions were inferred from the 14C-age of dissolved gases sampled beneath seasonal ice. Additionally, we measured concentrations and 14C values of gases emitted by ebullition and diffusion in summer to apportion C emission pathways. Using a multi-sourced mass balance approach, we found that whole-lake CH4 and CO2 emissions were predominantly sourced from relatively young C in most lakes. In Arctic lakes, CH4 originated from 850 14C-year old C on average, whereas dissolved CO2 was sourced from 400 14C-year old C, and represented 99% of total dissolved C flux. Although ancient C had a minimal influence (11% of total emissions), we discovered that lakes in finer-textured aeolian deposits (Yedoma) emitted twice as much ancient C as lakes in sandy regions. In Boreal, yedoma-type lakes, CH4 and CO2 were fueled by significantly older sources, and mass balance results estimated CH4-ebullition to comprise 50-60% of whole-lake CH4 emissions. The mean 14C-age of Boreal emissions was 6,000 14C-years for CH4-C, and 2

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

International Nuclear Information System (INIS)

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.

Estimation of lake water - groundwater interactions in meromictic mining lakes by modelling isotope signatures of lake water.

Science.gov (United States)

Seebach, Anne; Dietz, Severine; Lessmann, Dieter; Knoeller, Kay

2008-03-01

A method is presented to assess lake water-groundwater interactions by modelling isotope signatures of lake water using meteorological parameters and field data. The modelling of delta(18)O and deltaD variations offers information about the groundwater influx into a meromictic Lusatian mining lake. Therefore, a water balance model is combined with an isotope water balance model to estimate analogies between simulated and measured isotope signatures within the lake water body. The model is operated with different evaporation rates to predict delta(18)O and deltaD values in a lake that is only controlled by weather conditions with neither groundwater inflow nor outflow. Comparisons between modelled and measured isotope values show whether the lake is fed by the groundwater or not. Furthermore, our investigations show that an adaptation of the Craig and Gordon model [H. Craig, L.I. Gordon. Deuterium and oxygen-18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperature, Spoleto, E. Tongiorgi (Ed.), pp. 9-130, Consiglio Nazionale delle Ricerche, Laboratorio di Geologia Nucleare, Pisa (1965).] to specific conditions in temperate regions seems necessary.

The impact of an urban-industrial region on the magnitude and variability of persistent organic pollutant deposition to Lake Michigan.

Science.gov (United States)

Hornbuckle, Keri C; Green, Mark L

2003-09-01

A predictive model for gas-phase PCBs and trans-nonachlor over Lake Michigan has been constructed and the resulting data examined for trends. In this paper, we describe the model results to show how the magnitude and variability of a plume of contaminants from the Chicago area contributes to a highly variable region of net contaminant deposition over the entire lake. For the whole lake, gross annual deposition of PCBs is approximately 3200 kg, although the net annual gas exchange is not significantly different from zero. The data-driven model illustrates that on a daily basis, the net exchange of persistent organic pollutants (POPs) can change from net deposition to net volatilization depending on the area of plume impact. These findings suggest that i) control of urban areas can accelerate the rate of volatilization from lakes; and ii) release of POPs from urban areas is largely a result of volatilization processes.

Climate Change Impacts on Nutrient Losses of Two Watersheds in the Great Lakes Region

Directory of Open Access Journals (Sweden)

Lili Wang

2018-04-01

Full Text Available Non-point sources (NPS of agricultural chemical pollution are one major reason for the water quality degradation of the Great Lakes, which impacts millions of residents in the states and provinces that are bordering them. Future climate change will further impact water quality in both direct and indirect ways by influencing the hydrological cycle and processes of nutrient transportation and transformation, but studies are still rare. This study focuses on quantifying the impacts of climate change on nutrient (Nitrogen and Phosphorus losses from the two small watersheds (Walworth watershed and Green Lake watershed within the Great Lakes region. Analysis focused on changes through this century (comparing the nutrient loss prediction of three future periods from 2015 to 2099 with 30 years for each period against the historical nutrient estimation data from 1985 to 2008. The effects on total phosphorus and nitrate-nitrogen losses due to changes in precipitation quantity, intensity, and frequency, as well as air temperature, are evaluated for the two small watersheds, under three special report emission scenarios (SRES A2, A1B, B1. The newly developed Water Erosion Prediction Project-Water Quality (WEPP-WQ model is utilized to simulate nutrient losses with downscaled and bias corrected future climate forcing from two General Circulation Models (GFDL, HadCM3. For each watershed, the observed runoff and nutrient loads are used to calibrate and validate the model before the application of the WEPP-WQ model to examine potential impacts from future climate change. Total phosphorus loss is projected to increase by 28% to 89% for the Green Lake watershed and 25% to 108% for the Walworth watershed mainly due to the combined effects of increase of precipitation quantity, extreme storm events in intensity and frequency, and air temperature. Nitrate-nitrogen losses are projected to increase by 1.1% to 38% for the Green Lake watershed and 8% to 95% for the

Trends in summer chemistry linked to productivity in lakes recovering from acid deposition in the Adirondack region of New York

Science.gov (United States)

Momen, B.; Lawrence, G.B.; Nierzwicki-Bauer, S. A.; Sutherland, J.W.; Eichler, L.W.; Harrison, J.P.; Boylen, C.W.

2006-01-01

The US Environmental Protection Agency established the Adirondack Effects Assessment Program (AEAP) to evaluate and monitor the status of biological communities in lakes in the Adirondack region of New York that have been adversely affected by acid deposition. This program includes chemical analysis of 30 lakes, sampled two to three times each summer. Results of trends analysis for lake chemistry and chlorophyll a (chlor a) are presented for 1994 to 2003, and a general comparison is made with recent results of the Adirondack Long-Term Monitoring (ALTM) Program, which included chemical analysis of all but two of these lakes (plus an additional 24 lakes) monthly, year-round for 1992-2004. Increases in pH were found in 25 of the 30 AEAP lakes (P level of P level of P level of P level of P level of P chemistry were similar to those of the ALTM Program, although decreases in SO 42- concentrations were more evident in the year-round ALTM record. Overall, the results suggest (a) a degree of chemical recovery from acidification during the summer, (b) an increase in phytoplankton productivity, and (c) a decreasing trend in NO 3- concentrations resulting from the increased productivity. ?? 2007 Springer Science+Business Media, Inc.

The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989

Energy Technology Data Exchange (ETDEWEB)

Bowers, J.A.

1991-12-15

L Lake was constructed in 1985 on the upper regions of Steel Creek, SRS to mitigate the heated effluents from L Reactor. In addition to the NPDES permit specifications (Outfall L-007) for the L-Reactor outfall, DOE-SR executed an agreement with the South Carolina Department of Health and Environmental Control (SCDHEC), that thermal effluents from L-Reactor will not substantially alter ecosystem components in the approximate lower half of L Lake. This region should be inhabited by Balanced (Indigenous) Biological Communities (BBCs) in accordance with Section 316(a) of the Pollution Control (Clean Water) Act (Public Law 92-500). In response to this requirement the Environmental Sciences Section/Ecology Group initiated a comprehensive biomonitoring program which documented the development of BBCs in L Lake from January 1986 through December 1989. This report summarizes the principal results of the program with regards to BBC compliance issues and community succession in L Lake. The results are divided into six sections: water quality, macronutrients, and phytoplankton, aquatic macrophytes, zooplankton, benthic macroinvertebrates, fish, and community succession. One of the prime goals of the program was to detect potential reactor impacts on L Lake.

[Spatial Distribution Characteristics of Different Species Mercury in Water Body of Changshou Lake in Three Gorges Reservoir Region].

Science.gov (United States)

Bai, Wei-yang; Zhang, Cheng; Zhao, Zheng; Tang, Zhen-ya; Wang, Ding-yong

2015-08-01

An investigation on the concentrations and the spatial distribution characteristics of different species of mercury in the water body of Changshou Lake in Three Gorges Reservoir region was carried out based on the AreGIS statistics module. The results showed that the concentration of the total mercury in Changshou Lake surface water ranged from 0.50 to 3.78 ng x L(-1), with an average of 1.51 ng x L(-1); the concentration of the total MeHg (methylmercury) ranged from 0.10 to 0.75 ng x L(-1), with an average of 0.23 ng x L(-1). The nugget effect value of total mercury in surface water (50.65%), dissolved mercury (49.80%), particulate mercury (29.94%) and the activity mercury (26.95%) were moderate spatial autocorrelation. It indicated that the autocorrelation was impacted by the intrinsic properties of sediments (such as parent materials and rocks, geological mineral and terrain), and on the other hand it was also disturbed by the exogenous input factors (such as aquaculture, industrial activities, farming etc). The nugget effect value of dissolved methylmercury (DMeHg) in Changshou lake surface water (3.49%) was less than 25%, showing significant strong spatial autocorrelation. The distribution was mainly controlled by environmental factors in water. The proportion of total MeHg in total Hg in Changshou Lake water reached 30% which was the maximum ratio of the total MeHg to total Hg in freshwater lakes and rivers. It implied that mercury was easily methylated in the environment of Chanashou Lake.

Mercury in fish from the Pinchi Lake Region, British Columbia, Canada

International Nuclear Information System (INIS)

Weech, S.A.; Scheuhammer, A.M.; Elliott, J.E.; Cheng, K.M.

2004-01-01

Water, surface sediments, and <40 cm rainbow trout (Oncorhynchus mykiss) and northern pikeminnow (Ptychocheilus oregonensis) were collected from Pinchi Lake, British Columbia, and from several nearby reference lakes. Hg concentrations in sediment samples from Pinchi L. were highly elevated compared to sediments from reference lakes, especially in sites adjacent to and downstream of a former Hg mine. In both fish species examined, Hg concentration was positively related to age and/or fork length. In northern pikeminnow, Hg concentrations were also positively related to trophic level (δN). Hg concentrations in both fish species were highest in Pinchi L., and were higher in pikeminnow than in rainbow trout of similar size. Average Hg concentrations in small rainbow trout from all lakes, including Pinchi L., were lower than dietary levels reported to cause reproductive impairment in common loons (Gavia immer); however, Hg levels in small pikeminnow from Pinchi L. were sufficiently high to be of concern. The risk for Hg toxicity in the study area is greatest for animals that consume larger piscivorous fish such as larger northern pikeminnow or lake trout, which are known from previous studies to contain higher Hg concentrations

Developing Flexible, Integrated Hydrologic Modeling Systems for Multiscale Analysis in the Midwest and Great Lakes Region

Science.gov (United States)

Hamlet, A. F.; Chiu, C. M.; Sharma, A.; Byun, K.; Hanson, Z.

2016-12-01

Physically based hydrologic modeling of surface and groundwater resources that can be flexibly and efficiently applied to support water resources policy/planning/management decisions at a wide range of spatial and temporal scales are greatly needed in the Midwest, where stakeholder access to such tools is currently a fundamental barrier to basic climate change assessment and adaptation efforts, and also the co-production of useful products to support detailed decision making. Based on earlier pilot studies in the Pacific Northwest Region, we are currently assembling a suite of end-to-end tools and resources to support various kinds of water resources planning and management applications across the region. One of the key aspects of these integrated tools is that the user community can access gridded products at any point along the end-to-end chain of models, looking backwards in time about 100 years (1915-2015), and forwards in time about 85 years using CMIP5 climate model projections. The integrated model is composed of historical and projected future meteorological data based on station observations and statistical and dynamically downscaled climate model output respectively. These gridded meteorological data sets serve as forcing data for the macro-scale VIC hydrologic model implemented over the Midwest at 1/16 degree resolution. High-resolution climate model (4km WRF) output provides inputs for the analyses of urban impacts, hydrologic extremes, agricultural impacts, and impacts to the Great Lakes. Groundwater recharge estimated by the surface water model provides input data for fine-scale and macro-scale groundwater models needed for specific applications. To highlight the multi-scale use of the integrated models in support of co-production of scientific information for decision making, we briefly describe three current case studies addressing different spatial scales of analysis: 1) Effects of climate change on the water balance of the Great Lakes, 2) Future

Emergence of Viral hemorrhagic septicemia virus in the North American Great Lakes region is associated with low viral genetic diversity.

Science.gov (United States)

Thompson, Tarin M; Batts, William N; Faisal, Mohamed; Bowser, Paul; Casey, James W; Phillips, Kenneth; Garver, Kyle A; Winton, James; Kurath, Gael

2011-08-29

Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North America. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this viral emergence by comparing a partial glycoprotein (G) gene sequence (669 nt) of 108 isolates collected from 2003 to 2009 from 31 species and at 37 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVb within the major VHSV genetic group IV. Among these 108 isolates, genetic diversity was low, with a maximum of 1.05% within the 669 nt region. There were 11 unique sequences, designated vcG001 to vcG011. Two dominant sequence types, vcG001 and vcG002, accounted for 90% (97 of 108) of the isolates. The vcG001 isolates were most widespread. We saw no apparent association of sequence type with host or year of isolation, but we did note a spatial pattern, in which vcG002 isolates were more prevalent in the easternmost sub-regions, including inland New York state and the St. Lawrence Seaway. Different sequence types were found among isolates from single disease outbreaks, and mixtures of types were evident within 2 isolates from individual fish. Overall, the genetic diversity of VHSV in the Great Lakes region was found to be extremely low, consistent with an introduction of a new virus into a geographic region with previously naive host populations.

Emergence of viral hemorrhagic septicemia virus in the North American Great Lakes region is associated with low viral genetic diversity

Science.gov (United States)

Thompson, T.M.; Batts, W.N.; Faisal, M.; Bowser, P.; Casey, J.W.; Phillips, K.; Garver, K.A.; Winton, J.; Kurath, G.

2011-01-01

Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North Ame­rica. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this viral emergence by comparing a partial glycoprotein (G) gene sequence (669 nt) of 108 isolates collected from 2003 to 2009 from 31 species and at 37 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVb within the major VHSV genetic group IV. Among these 108 isolates, genetic diversity was low, with a maximum of 1.05% within the 669 nt region. There were 11 unique sequences, designated vcG001 to vcG011. Two dominant sequence types, vcG001 and vcG002, accounted for 90% (97 of 108) of the isolates. The vcG001 isolates were most widespread. We saw no apparent association of sequence type with host or year of isolation, but we did note a spatial pattern, in which vcG002 isolates were more prevalent in the easternmost sub-regions, including inland New York state and the St. Lawrence Seaway. Different sequence types were found among isolates from single disease outbreaks, and mixtures of types were evident within 2 isolates from ­individual fish. Overall, the genetic diversity of VHSV in the Great Lakes region was found to be extremely low, consistent with an introduction of a new virus into a geographic region with ­previously naïve host populations.

Differential response of vegetation in Hulun Lake region at the northern margin of Asian summer monsoon to extreme cold events of the last deglaciation

Science.gov (United States)

Zhang, Shengrui; Xiao, Jule; Xu, Qinghai; Wen, Ruilin; Fan, Jiawei; Huang, Yun; Yamagata, Hideki

2018-06-01

The response of vegetation to extreme cold events during the last deglaciation is important for assessing the impact of possible extreme climatic events on terrestrial ecosystems under future global warming scenarios. Here, we present a detailed record of the development of regional vegetation in the northern margin of Asian summer monsoon during the last deglaciation (16,500-11,000 cal yr BP) based on a radiocarbon-dated high-resolution pollen record from Hulun Lake, northeast China. The results show that the regional vegetation changed from subalpine meadow-desert steppe to mixed coniferous and deciduous forest-typical steppe during the last deglaciation. However, its responses to the Heinrich event 1 (H1) and the Younger Dryas event (YD) were significantly different: during the H1 event, scattered sparse forest was present in the surrounding mountains, while within the lake catchment the vegetation cover was poor and was dominated by desert steppe. In contrast, during the YD event, deciduous forest developed and the proportion of coniferous forest increased in the mountains, the lake catchment was occupied by typical steppe. We suggest that changes in Northern Hemisphere summer insolation and land surface conditions (ice sheets and sea level) caused temperature and monsoonal precipitation variations that contributed to the contrasting vegetation response during the two cold events. We conclude that under future global warming scenarios, extreme climatic events may cause a deterioration of the ecological environment of the Hulun Lake region, resulting in increased coniferous forest and decreased total forest cover in the surrounding mountains, and a reduction in typical steppe in the lake catchment.

Petrology of the Fort Smith - Great Slave Lake radiometric high near Pilot Lake, N.W.T

International Nuclear Information System (INIS)

Burwash, R.A.; Cape, D.F.

1981-01-01

Near Pilot Lake, the east boundary of the Fort Smith - Great Slave Lake radiometric high coincides with the contact of a well-foliated, porphyroblastic microcline-plagioclase-quartz-garnet-biotite gneiss (Pilot Lake Gneiss) with a hybrid assemblage of quartzite, mica schist, garnet-cordierite gneiss, and minor amphibolite (Variable Paragneiss). Anomalously high concentrations of uranium and thorium are associated with mafic-rich, lenticular bodies with a mineral assemblage biotite + monazite + zircon + ilmenite + hematite +- plagioclase +- quartz, within both the Variable Paragneiss and the Pilot Lake Gneiss. Corundum and spinel occur in the mafic lenses and sillimanite, kyanite, and hypersthene in other inclusions of the Pilot Lake Gneiss. The ilmenite-magnetite--monazite-zircon-apatite assemblage is interpreted as a 'black sand' concentration in a clastic sedimentary sequence subsequently metamorphosed by a regional granulite facies event. A granite pluton intruded during the same orogenic cycle assimilated the clastic metasedimentary rocks containing black sand interlayers, becoming enriched in thorium from the monazite. A second metamorphic event at lower P-T conditions, accompanied by strong cataclasis, developed the texture of the Pilot Lake Gneiss as now observed. Shearing within the gneiss locally concentrated hematite + quartz + uranium. Regional tectonic extrapolations suggest that the pyroxene granulite event was Kenoran and the later amphibolite event Hudsonian. (author)

Regional Geomorphological Conditions Related to Recent Changes of Glacial Lakes in the Issyk-Kul Basin, Northern Tien Shan

Directory of Open Access Journals (Sweden)

Mirlan Daiyrov

2018-03-01

either a vanishing or a short-lived type. In this way, the large variability in the number of each lake type and the distribution of types over this four-year period arises from regional geomorphological conditions and not directly from the local short-term summer temperature anomaly and precipitation or glacier recession.

Regional maximum rainfall analysis using L-moments at the Titicaca Lake drainage, Peru

Science.gov (United States)

Fernández-Palomino, Carlos Antonio; Lavado-Casimiro, Waldo Sven

2017-08-01

The present study investigates the application of the index flood L-moments-based regional frequency analysis procedure (RFA-LM) to the annual maximum 24-h rainfall (AM) of 33 rainfall gauge stations (RGs) to estimate rainfall quantiles at the Titicaca Lake drainage (TL). The study region was chosen because it is characterised by common floods that affect agricultural production and infrastructure. First, detailed quality analyses and verification of the RFA-LM assumptions were conducted. For this purpose, different tests for outlier verification, homogeneity, stationarity, and serial independence were employed. Then, the application of RFA-LM procedure allowed us to consider the TL as a single, hydrologically homogeneous region, in terms of its maximum rainfall frequency. That is, this region can be modelled by a generalised normal (GNO) distribution, chosen according to the Z test for goodness-of-fit, L-moments (LM) ratio diagram, and an additional evaluation of the precision of the regional growth curve. Due to the low density of RG in the TL, it was important to produce maps of the AM design quantiles estimated using RFA-LM. Therefore, the ordinary Kriging interpolation (OK) technique was used. These maps will be a useful tool for determining the different AM quantiles at any point of interest for hydrologists in the region.

Holocene evolution of lakes in the forest-tundra biome of northern Manitoba, Canada

Science.gov (United States)

Hobbs, William O.; Edlund, Mark B.; Umbanhowar, Charles E.; Camill, Philip; Lynch, Jason A.; Geiss, Christoph; Stefanova, Vania

2017-03-01

The late-Quaternary paleoenvironmental history of the western Hudson Bay region of Subarctic Canada is poorly constrained. Here, we present a regional overview of the post-glacial history of eight lakes which span the forest-tundra biome in northern Manitoba. We show that during the penultimate drainage phase of Lake Agassiz the lake water had an estimated pH of ∼6.0, with abundant quillwort (Isöetes spp.) along the lakeshore and littoral zone and some floating green algae (Botryococcus spp. and Pediastrum sp.). Based on multiple sediment proxies, modern lake ontogeny in the region commenced at ∼7500 cal yrs BP. Pioneering diatom communities were shaped by the turbid, higher alkalinity lake waters which were influenced by base cation weathering of the surrounding till following Lake Agassiz drainage. By ∼7000 cal yrs BP, soil development and Picea spp. establish and the lakes began a slow trajectory of acidification over the remaining Holocene epoch. The natural acidification of the lakes in this region is slow, on the order of several millennia for one pH unit. Each of the study lakes exhibit relatively stable aquatic communities during the Holocene Thermal Maximum, suggesting this period is a poor analogue for modern climatic changes. During the Neoglacial, the beginning of the post-Little Ice Age period represents the most significant climatic event to impact the lakes of N. Manitoba. In the context of regional lake histories, the rate of diatom floristic change in the last 200-300 years is unprecedented, with the exception of post-glacial lake ontogeny in some of the lakes. For nearly the entire history of the lakes in this region, there is a strong linkage between landscape development and the aquatic ecosystems; however this relationship appears to become decoupled or less strong in the post-LIA period. Significant 20th century changes in the aquatic ecosystem cannot be explained wholly by changes in the terrestrial ecosystem, suggesting that future

Influence of permafrost on lake terraces of Lake Heihai (NE Tibetan Plateau)

Science.gov (United States)

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

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

OpenAIRE

Laijian Wang; Lachun Wang; Pengcheng Yin; Haiyang Cui; Longwu Liang; Zhenbo Wang

2017-01-01

Mining subsided lakes are major obstacles for ecological restoration and resource reuse in mining regions. Transforming mining subsided lakes into artificial wetlands is an ecological restoration approach that has been attempted in China in recent years, but a value assessment of the approach still needs systematic research. This paper considers Jiuli Lake wetland, an artificial wetland derived from restoration of a mining subsided lake in plain area, as a case study. A value assessment model...

Review Article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru

Directory of Open Access Journals (Sweden)

A. Emmer

2013-06-01

Full Text Available Glacial lake outburst floods (GLOFs and related debris flows represent a significant threat in high mountainous areas across the globe. It is necessary to quantify this threat so as to mitigate their catastrophic effects. Complete GLOF hazard assessment incorporates two phases: the probability of water release from a given glacial lake is estimated through lake and breach hazard assessment while the endangered areas are identified during downstream hazard assessment. This paper outlines a number of methods of lake and breach hazard assessment, which can be grouped into three categories: qualitative, of which we outline eight; semi-quantitative, of which we outline two; and quantitative, of which we outline three. It is considered that five groups of critical parameters are essential for an accurate regionally focused hazard assessment method for moraine-dammed lakes in the Cordillera Blanca. These comprise the possibility of dynamic slope movements into the lake, the possibility of a flood wave from a lake situated upstream, the possibility of dam rupture following a large earthquake, the size of the dam freeboard (or ratio of dam freeboard, and a distinction between natural dams and those with remedial work. It is shown that none of the summarised methods uses all these criteria with, at most, three of the five considered by the outlined methods. A number of these methods were used on six selected moraine-dammed lakes in the Cordillera Blanca: lakes Quitacocha, Checquiacocha, Palcacocha, Llaca, Rajucolta, and Tararhua. The results have been compared and show that each method has certain advantages and disadvantages when used in this region. These methods demonstrate that the most hazardous lake is Lake Palcacocha.

Paleoecology of a Northern Michigan Lake and the relationship among climate, vegetation, and Great Lakes water levels

Science.gov (United States)

Booth, R.K.; Jackson, S.T.; Thompson, T.A.

2002-01-01

We reconstructed Holocene water-level and vegetation dynamics based on pollen and plant macrofossils from a coastal lake in Upper Michigan. Our primary objective was to test the hypothesis that major fluctuations in Great Lakes water levels resulted in part from climatic changes. We also used our data to provide temporal constraints to the mid-Holocene dry period in Upper Michigan. From 9600 to 8600 cal yr B.P. a shallow, lacustrine environment characterized the Mud Lake basin. A Sphagnum-dominated wetland occupied the basin during the mid-Holocene dry period (???8600 to 6600 cal yr B.P.). The basin flooded at 6600 cal yr B.P. as a result of rising water levels associated with the onset of the Nipissing I phase of ancestral Lake Superior. This flooding event occured contemporaneously with a well-documented regional expansion of Tsuga. Betula pollen increased during the Nipissing II phase (4500 cal yr B.P.). Macrofossil evidence from Mud Lake suggests that Betula alleghaniensis expansion was primarily responsible for the rising Betula pollen percentages. Major regional and local vegetational changes were associated with all the major Holocene highstands of the western Great Lakes (Nipissing I, Nipissing II, and Algoma). Traditional interpretations of Great Lakes water-level history should be revised to include a major role of climate. ?? 2002 University of Washington.

The Water Level Fall of Lake Megali Prespa (N Greece): an Indicator of Regional Water Stress Driven by Climate Change and Amplified by Water Extraction?

Science.gov (United States)

van der Schriek, Tim; Giannakopoulos, Christos

2014-05-01

The Mediterranean stands out globally due to its sensitivity to (future) climate change, with future projections predicting an increase in excessive drought events and declining rainfall. Regional freshwater ecosystems are particularly threatened: precipitation decreases, while extreme droughts increase and human impacts intensify (e.g. water extraction, drainage, pollution and dam-building). Many Mediterranean lake-wetland systems have shrunk or disappeared over the past two decades. Protecting the remaining systems is extremely important for supporting global biodiversity and for ensuring sustainable water availability. This protection should be based on a clear understanding of lake-wetland hydrological responses to natural and human-induced changes, which is currently lacking in many parts of the Mediterranean. The interconnected Prespa-Ohrid Lake system is a global hotspot of biodiversity and endemism. The unprecedented fall in water level (~8m) of Lake Megali Prespa threatens this system, but causes remain debated. Modelling suggests that the S Balkan will experience rainfall and runoff decreases of ~30% by 2050. However, projections revealing the potential impact of these changes on future lake level are unavailable as lake regime is not understood. A further drop in lake level may have serious consequences. The Prespa Lakes contribute ~25% of the total inflow into Lake Ohrid through underground karst channels; falling lake levels decrease this discharge. Lake Ohrid, in turn, feeds the Drim River. This entire catchment may therefore be affected by falling lake levels; its water resources are of great importance for Greece, Albania, FYROM and Montenegro (e.g. tourism, agriculture, hydro-energy, urban & industrial use). This new work proves that annual water level fluctuations of Lake Megali Prespa are predominantly related to precipitation during the first 7 months (Oct-Apr) of the hydrological year (Oct-Sep). Lake level is very sensitive to regional and

Environmental status of the Lake Michigan region. Volume 14. Birds of the Lake Michigan drainage basin

Energy Technology Data Exchange (ETDEWEB)

Wallace, G.J.

1977-07-01

This report characterizes the bird life found in 100 counties of the four states peripheral to Lake Michigan. It discusses major habitats (the Lake Michigan shoreline, inland lakes, rivers and streams, marshes, fields and open spaces, and woodlots) and associates specific birds with habitats according to preferences for space and food. It also discusses the special attributes of state parks and lakeshores, refuges and sanctuaries, and other special areas which are attractive to avifauna. Patterns of historical occurrence and abundance, and the influence of pesticides and pollution, disease, and hunting pressure are explored to place present occurrence in a modern perspective. Migration patterns are discussed to explain increases and decreases which occur in nonresident avifauna of the Basin. The distribution and habits of birds that occur regularly in the Basin are described in an annotated list; a more complete list is presented in a table which encapsulates data for rapid and convenient reference. Separate sections deal with extinct, extirpated, and introduced species, and with endangered, threatened, and declining species.

Habitat capacity for cougar recolonization in the Upper Great Lakes region.

Science.gov (United States)

O Neil, Shawn T; Rahn, Kasey C; Bump, Joseph K

2014-01-01

Recent findings indicate that cougars (Puma concolor) are expanding their range into the midwestern United States. Confirmed reports of cougar in Michigan, Minnesota, and Wisconsin have increased dramatically in frequency during the last five years, leading to speculation that cougars may re-establish in the Upper Great Lakes (UGL) region, USA. Recent work showed favorable cougar habitat in northeastern Minnesota, suggesting that the northern forested regions of Michigan and Wisconsin may have similar potential. Recolonization of cougars in the UGL states would have important ecological, social, and political impacts that will require effective management. Using Geographic Information Systems (GIS), we extended a cougar habitat model to Michigan and Wisconsin and incorporated primary prey densities to estimate the capacity of the region to support cougars. Results suggest that approximately 39% (>58,000 km2) of the study area could support cougars, and that there is potential for a population of approximately 500 or more animals. An exploratory validation of this habitat model revealed strong association with 58 verified cougar locations occurring in the study area between 2008 and 2013. Spatially explicit information derived from this study could potentially lead to estimation of a viable population, delineation of possible cougar-human conflict areas, and the targeting of site locations for current monitoring. Understanding predator-prey interactions, interspecific competition, and human-wildlife relationships is becoming increasingly critical as top carnivores continue to recolonize the UGL region.

Habitat capacity for cougar recolonization in the Upper Great Lakes region.

Directory of Open Access Journals (Sweden)

Shawn T O Neil

Full Text Available BACKGROUND: Recent findings indicate that cougars (Puma concolor are expanding their range into the midwestern United States. Confirmed reports of cougar in Michigan, Minnesota, and Wisconsin have increased dramatically in frequency during the last five years, leading to speculation that cougars may re-establish in the Upper Great Lakes (UGL region, USA. Recent work showed favorable cougar habitat in northeastern Minnesota, suggesting that the northern forested regions of Michigan and Wisconsin may have similar potential. Recolonization of cougars in the UGL states would have important ecological, social, and political impacts that will require effective management. METHODOLOGY/PRINCIPAL FINDINGS: Using Geographic Information Systems (GIS, we extended a cougar habitat model to Michigan and Wisconsin and incorporated primary prey densities to estimate the capacity of the region to support cougars. Results suggest that approximately 39% (>58,000 km2 of the study area could support cougars, and that there is potential for a population of approximately 500 or more animals. An exploratory validation of this habitat model revealed strong association with 58 verified cougar locations occurring in the study area between 2008 and 2013. CONCLUSIONS/SIGNIFICANCE: Spatially explicit information derived from this study could potentially lead to estimation of a viable population, delineation of possible cougar-human conflict areas, and the targeting of site locations for current monitoring. Understanding predator-prey interactions, interspecific competition, and human-wildlife relationships is becoming increasingly critical as top carnivores continue to recolonize the UGL region.

Average niche breadths of species in lake macrophyte communities respond to ecological gradients variably in four regions on two continents.

Science.gov (United States)

Alahuhta, Janne; Virtala, Antti; Hjort, Jan; Ecke, Frauke; Johnson, Lucinda B; Sass, Laura; Heino, Jani

2017-05-01

Different species' niche breadths in relation to ecological gradients are infrequently examined within the same study and, moreover, species niche breadths have rarely been averaged to account for variation in entire ecological communities. We investigated how average environmental niche breadths (climate, water quality and climate-water quality niches) in aquatic macrophyte communities are related to ecological gradients (latitude, longitude, altitude, species richness and lake area) among four distinct regions (Finland, Sweden and US states of Minnesota and Wisconsin) on two continents. We found that correlations between the three different measures of average niche breadths and ecological gradients varied considerably among the study regions, with average climate and average water quality niche breadth models often showing opposite trends. However, consistent patterns were also found, such as widening of average climate niche breadths and narrowing of average water quality niche breadths of aquatic macrophytes along increasing latitudinal and altitudinal gradients. This result suggests that macrophyte species are generalists in relation to temperature variations at higher latitudes and altitudes, whereas species in southern, lowland lakes are more specialised. In contrast, aquatic macrophytes growing in more southern nutrient-rich lakes were generalists in relation to water quality, while specialist species are adapted to low-productivity conditions and are found in highland lakes. Our results emphasise that species niche breadths should not be studied using only coarse-scale data of species distributions and corresponding environmental conditions, but that investigations on different kinds of niche breadths (e.g., climate vs. local niches) also require finer resolution data at broad spatial extents.

[Land Use Pattern Change and Regional Sustainability Evaluation of Wetland in Jiaogang Lake].

Science.gov (United States)

Yang, Yang; Cai, Yi-min; Bai, Yan-ying; Chen, Wei-ping; Yang, Xiu-chao

2015-06-01

Changes in land use and sustainability evaluation of wetland in Jiaogang Lake from 1995 to 2013 were analyzed, based on the land use change models and an index system, supported by RS, GIS, and social statistical data. The results showed: (1) dry land, paddy field, and building land were the predominant landscape in the study area. The arable land was mainly converted during 1995-2000, which was driven by the extension of agriculture, and the building land increased significantly during 2010-2013, which was driven by the tourism development. (2) Compared to the beginning research area, the building land increased by 123.3%, and the wetland decreased by 23.15%. The land system was at risk for a low proportion of wetland, scarcity of unused land, and the fragmented landscape. (3) The regional sustainability results were bad level, bad level, poor level, good level, and poor level during the different periods, with some room for improvement. (4) The fitness of regional sustainability in study area yielded satisfactory results in 2010, owing to the rapid growth of regional productivity and the regional stability. Since 2010, with the increasing environmental load, the regional sustainability fell down to the poor level. The obstruction of sustainable development is necessary to be addressed in the study area.

Is Lake Chabot Eutrophic?

Science.gov (United States)

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

2013-12-01

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

A Systematic Study of Zerbar Lake Restoration

Science.gov (United States)

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

Social-Ecological Thresholds in a Changing Boreal Landscape: Insights from Cree Knowledge of the Lesser Slave Lake Region of Alberta, Canada

Directory of Open Access Journals (Sweden)

Brenda L. Parlee

2012-06-01

Full Text Available Drawing on the traditional ecological knowledge (TEK of the Lesser Slave Lake Cree, this paper shares understanding of how resource development has affected water, fish, forests, and wildlife as well as the well-being of Cree communities in the Lesser Slave Lake region of Alberta, Canada. In addition to descriptive observations of change, the narratives point to social-ecological thresholds or tipping points in the relationship of Cree harvesters to local lands and resources. Specifically, the study speaks to the echoing effects of ecological loss and degradation on traditional livelihood practices over the last 100 years highlighting the complexity of cumulative effects as well as the challenges of balancing resource development in the region with alternative land uses including those valued by Alberta's Aboriginal peoples.

Land Use and Land Cover Change in the Qinghai Lake Region of the Tibetan Plateau and Its Impact on Ecosystem Services

Directory of Open Access Journals (Sweden)

Jian Gong

2017-07-01

Full Text Available Exploration of land use and land cover change (LULCC and its impacts on ecosystem services in Tibetan plateau is valuable for landscape and environmental conservation. In this study, we conduct spatial analysis on empirical land use and land cover data in the Qinghai Lake region for 1990, 2000, and 2010 and simulate land cover patterns for 2020. We then evaluate the impacts of LULCC on ecosystem service value (ESV, and analyze the sensitivity of ESV to LULCC to identify the ecologically sensitive area. Our results indicate that, from 1990 to 2010, the area of forest and grassland increased while the area of unused land decreased. Simulation results suggest that the area of grassland and forest will continue to increase and the area of cropland and unused land will decrease for 2010–2020. The ESV in the study area increased from 694.50 billion Yuan in 1990 to 714.28 billion Yuan in 2000, and to 696.72 billion Yuan in 2020. Hydrology regulation and waste treatment are the top two ecosystem services in this region. The towns surrounding the Qinghai Lake have high ESVs, especially in the north of the Qinghai Lake. The towns with high ESV sensitivity to LULCC are located in the northwest, while the towns in the north of the Qinghai Lake experienced substantial increase in sensitivity index from 2000–2010 to 2010–2020, especially for three regulation services and aesthetic landscape provision services.

Characteristics of petroleum contaminants and their distribution in Lake Taihu, China.

Science.gov (United States)

Guo, Jixiang; Fang, Jia; Cao, Jingjing

2012-08-31

Taihu Lake is a typical plain eutrophic shallow lake. With rapidly economic development of the lake area, the petroleum products and oil wastewater produced in various processes have been inevitably discharged into Taihu Lake. As the major fresh water resource in the economically developed region of Yangtze River Delta, the water quality and environmental condition of Taihu Lake have the direct bearing on the natural environment and sustainable development of economy in this region. For this reason we carried out the study to explore the composition, distribution characteristics and sources of petroleum contaminants in Taihu Lake. The aim of this study was to provide the basis for standard management and pollution control of the Taihu Lake environment. The result showed that water samples from near industrial locations were of relatively higher petroleum contaminants concentrations. The oil pollutants concentrations in different areas of Lake Taihu ranged from 0.106 mg/L to 1.168 mg/L, and the sequence of total contents distribution characteristics of petroleum pollutants from high to low in different regions of Taihu Lake was: "Dapu", "Xiaomeikou", "Zhushan Bay", "Lake center", "Qidu". The results showed that total concentrations of n-alkanes and PAHs ranged from 0.045 to 0.281 mg/L and from 0.011 to 0.034 mg/L respectively. In the same region, the concentrations of hydrocarbon pollutants in the surface and bottom of the lake were higher than that in the middle. This paper reached a conclusion that the petroleum contaminants in Taihu Lake mainly derived from petroleum pollution caused by human activities as indicated by OEP, bimodal distribution, CPI, Pr/Ph ratio, the LMW/HMW ratio and other evaluation indices for sources of n-alkanes and polycyclic aromatic hydrocarbons (PAHs).

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

Science.gov (United States)

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...

Environmental and spatial factors influencing the distribution of cladocerans in lakes across the central Canadian Arctic treeline region

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John P. SMOL

2010-02-01

Full Text Available We examine the role of local environmental and spatial factors in explaining variation in the composition of cladoceran assemblages from surface sediments within a set of 50 lakes spanning a broad southwest to northeast transect across the central Canadian Arctic treeline region from Yellowknife (Northwest Territories to the northern boundary of the Thelon Game Sanctuary (Nunavut Territory. Within each lake, the cladoceran fauna was identified based on the subfossil exoskeletal remains preserved in recently deposited lake sediments. Physical and chemical limnological data were measured in August of 1996 and 1998. Spatial data were generated based on latitude and longitude using Principal Coordinates of Neighbors Matrices analysis (PCNM. The relationships between cladocerans and the measured environmental and spatial variables were examined using both unconstrained (Principal Components Analysis, PCA and constrained (Redundancy Analysis, RDA ordination techniques. Variance partitioning, based on partial RDAs, was used to identify the relative importance of significant environmental and spatial explanatory variables. Three environmental variables were identified as significantly influencing cladoceran community structure: surface water temperature, dissolved organic carbon (DOC, and total phosphorus (TP. Five PCNM-generated spatial variables were also significant in explaining cladoceran distributions. Variance partitioning attributed 14% of the variance in the distribution of Cladocera to spatial factors, an additional 10% to spatially-structured environmental variables, and 8% to environmental factors that were not spatially-structured. Within the central Canadian Arctic treeline region, spatial and other environmental processes had an important influence on the distribution of cladoceran communities. The strong influence of spatial factors was related to the large ecoclimatic gradient across treeline. The distribution patterns of cladocerans

[Spatial distribution of COD and the correlations with other parameters in the northern region of Lake Taihu].

Science.gov (United States)

Zhang, Yun-lin; Yang, Long-yuan; Qin, Bo-qiang; Gao, Guang; Luo, Lian-cong; Zhu, Guang-wei; Liu, Ming-liang

2008-06-01

Spatial variation of chemical oxygen demand (COD) concentration was documented and significant correlations between COD concentration and chromophoric dissolved organic matter (CDOM) absorption, fluorescence, DOC concentration were found based on a cruise sampling in the northern region of Lake Taihu in summer including 42 samplings. The possible source of COD was also discussed using every two cruise samplings in summer and winter, respectively. The COD concentration ranged from 3.77 to 7.96 mg x L(-1) with a mean value of (5.90 +/- 1.54) mg x L(-1). The mean COD concentrations in Meiliang Bay and the central lake basin were (6.93 +/- 0.89) mg x L(-1) and (4.21 +/- 0.49) mg x L(-1) respectively. A significant spatial difference was found between Meiliang Bay and the central lake basin in COD concentration, CDOM absorption coefficient, fluorescence, DOC and phytoplankton pigment concentrations, decreasing from the river mouth to inner bay, outer bay and the central lake basin. Significant correlations between COD concentration and CDOM absorption, fluorescence, DOC concentration, suggested that COD concentration could be estimated and organic pollution could be assessed using CDOM absorption retrieved from remote sensing images. Significant and positive correlation was found between COD concentration and chlorophyll a concentration in summer. However, the correlation was weak or no correlation was found in winter. Furthermore, a significant higher COD concentration was found in summer than in winter (p summer, except for river terrestrial input.

A 60-year record of 129I in Taal Lake sediments (Philippines): Influence of human nuclear activities at low latitude region

DEFF Research Database (Denmark)

Zhang, Luyuan; Hou, Xiaolin; Li, Hong-chun

2017-01-01

in the Taal Lake core appears to be the signal of the Chernobyl accident in 1986. In addition, volcanic activities are reflected in the iodine isotope profiles in the sediment core, suggesting the potential of using iodine isotopes as an indicator of volcanic eruptions.......The influence of human nuclear activities on environmental radioactivity is not well known at low latitude region that are distant from nuclear tests sites and nuclear facilities. A sediment core collected from Taal Lake in the central Philippines was analyzed for 129I and 127I to investigate...

Lake and lake-related drainage area parameters for site investigation program

Energy Technology Data Exchange (ETDEWEB)

Blomqvist, P.; Brunberg, A.K. [Uppsala Univ. (Sweden). Dept. of Limnology; Brydsten, L [Umeaa Univ. (Sweden). Dept. of Ecology and Environmental Science

2000-09-01

ecosystem. Altogether, the selected parameters will create a solid basis for determination of the lake type and its representativity of the region where it is located and of the function and eventual malfunction of the inherent ecosystem.

Lake and lake-related drainage area parameters for site investigation program

International Nuclear Information System (INIS)

Blomqvist, P.; Brunberg, A.K.; Brydsten, L

2000-09-01

. Altogether, the selected parameters will create a solid basis for determination of the lake type and its representativity of the region where it is located and of the function and eventual malfunction of the inherent ecosystem

Are all temperate lakes eutrophying in a warmer world?

Science.gov (United States)

Paltsev, A.; Creed, I. F.

2017-12-01

Freshwater lakes are at risk of eutrophication due to climate change and intensification of human activities on the planet. In relatively undisturbed areas of the temperate forest biome, lakes are "sentinels" of the effects of rising temperatures. We hypothesise that rising temperatures are driving a shift from nutrient-poor oligotrophic states to nutrient-rich eutrophic states. To test this hypothesis, we examined a time series of satellite based chlorophyll-a (a proxy of algal biomass) of 12,000+ lakes over 30 years in the Canadian portion of the Laurentian Great Lakes basin. From the time series, non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals was used as an indicator of lake stability. Four classes of lake stability were identified: (1) stable (SD is consistently low); (2) destabilizing (SD increases over time); (3) unstable (SD is consistently high); and (4) stabilizing lakes (SD decreases over time). Stable lakes were either oligotrophic or eutrophic indicating the presence of two stable states in the region. Destabilizing lakes were shifting from oligotrophic to lakes with a higher trophic status (indicating eutrophication), unstable lakes were mostly mesotrophic, and stabilizing lakes were shifting from eutrophic to the lakes with lower trophic status (indicating oligotrophication). In contrast to common expectations, while many lakes (2142) were shifting from oligotrophic to eutrophic states, more lakes (3199) were showing the opposite trend and shifting from eutrophic to oligotrophic states. This finding reveals a complexity of lake responses to rising temperatures and the need to improve understanding of why some lakes shift while others do not. Future work is focused on exploring the interactive effects of global, regional, and local drivers of lake trophic states.

Regional-scale GIS-models for assessment of hazards from glacier lake outbursts: evaluation and application in the Swiss Alps

Directory of Open Access Journals (Sweden)

C. Huggel

2003-01-01

Full Text Available Debris flows triggered by glacier lake outbursts have repeatedly caused disasters in various high-mountain regions of the world. Accelerated change of glacial and periglacial environments due to atmospheric warming and increased anthropogenic development in most of these areas raise the need for an adequate hazard assessment and corresponding modelling. The purpose of this paper is to pro-vide a modelling approach which takes into account the current evolution of the glacial environment and satisfies a robust first-order assessment of hazards from glacier-lake outbursts. Two topography-based GIS-models simulating debris flows related to outbursts from glacier lakes are presented and applied for two lake outburst events in the southern Swiss Alps. The models are based on information about glacier lakes derived from remote sensing data, and on digital elevation models (DEM. Hydrological flow routing is used to simulate the debris flow resulting from the lake outburst. Thereby, a multiple- and a single-flow-direction approach are applied. Debris-flow propagation is given in probability-related values indicating the hazard potential of a certain location. The debris flow runout distance is calculated on the basis of empirical data on average slope trajectory. The results show that the multiple-flow-direction approach generally yields a more detailed propagation. The single-flow-direction approach, however, is more robust against DEM artifacts and, hence, more suited for process automation. The model is tested with three differently generated DEMs (including aero-photogrammetry- and satellite image-derived. Potential application of the respective DEMs is discussed with a special focus on satellite-derived DEMs for use in remote high-mountain areas.

Housing Archetype Analysis for Home Energy-Efficient Retrofit in the Great Lakes Region

Energy Technology Data Exchange (ETDEWEB)

Kim, S. -K. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Mrozowski, T. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Harrell-Seyburn, A. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Ehrlich, N. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Hembroff, L. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Lieburn, B. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Mazor, M. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); McIntyre, A. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Mutton, C. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Parsons, G. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Syal, M. G. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States); Wilkinson, R. [Cost Effective Energy Retrofit (CEER) Team, Midland, MI (United States)

2014-09-01

This project report details activities and results of the "Market Characterization" project undertaken by the Cost Effective Energy Retrofit (CEER) team targeted toward the DOE goal of achieving 30%-50% reduction in existing building energy use. CEER consists of members from the Dow Chemical Company, Michigan State University, Ferris State University, and Habitat for Humanity Kent County. The purpose of this market characterization project was to identify housing archetypes which are dominant within the Great Lakes region and therefore offer significant potential for energy-efficient retrofit research and implementation due to the substantial number of homes possessing similar characteristics. Understanding the characteristics of housing groups referred to as "archetypes" by vintage, style, and construction characteristics can allow research teams to focus their retrofit research and develop prescriptive solutions for those structure types which are prevalent and offer high potential uptake within a region or market.

Trophic development in a volcanic lake with closed hydric balance. Lake Martignano

International Nuclear Information System (INIS)

Falleni, F.; Bruno, M.; Marchiori, E.; Congestri, R.; Gasperi, E.; Brambullo, M.; Amadeio, R.

2000-01-01

Martignano lake is a particular charming volcanic lake in the countryside of Rome. Recently it was included in a project of Regional Wildlife Park. The lack of immissaries and emissaries, the quite long renewal time and the very short homeothermic period of two-months in a year, make the lake susceptible of trophic evolution. The comparison between the present data and those from previous studies seems to confirm such a slow development towards this way, with a nutrient level (nitrate 0.97 mg/L; total phosphorus 11.14 μg/L) and chlorophyll a concentrations (10.68 μg/L), typical of mesotrophic waters. The analysis of nutrient data expressed as annual mean value in percentage from the coastal stations, suggests an under lied farming influence, and points out the need to adopt fast reduction measures, to lower the phosphorus load in acceptable levels for the lake ecosystem [it

[Pollution distribution and potential ecological risk assessment of heavy metals in sediments from the different eastern dredging regions of Lake Taihu].

Science.gov (United States)

Mao, Zhi-Gang; Gu, Xiao-Hong; Lu, Xiao-Ming; Zeng, Qing-Fei; Gu, Xian-Kun; Li, Xu-Guang

2014-01-01

In order to investigate the distribution characteristics of nutrients and heavy metals in sediments from different eastern dredging regions of Lake Taihu, the surface and core sediment samples at 5 sites (in East Taihu Lake and Xukou Bay) were collected in 2012. Contents of nutrients (TOC, TN and TP) and heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in the sediments were measured and the pollution degrees of heavy metals were evaluated with the potential ecological risk method. The results showed that the heavy metal contents in Xukou Bay were generally higher than those in East Taihu Lake, whereas the nutrients contents showed the reverse trend. There were significant differences between the phytoplankton-dominated and culture lake regions. The concentrations of both nutrients and heavy metals decreased with increasing profile depth. Moreover, the contents of nutrients and heavy metals in the sediments of all dredged areas were lower than those in the un-dredged areas, suggesting that dredging may be a useful approach for decreasing nutrients and heavy metals loading in sediments, but its effectiveness decreased with time. Significant positive correlations were found among different heavy metals and nutrients, indicating that they were from the same pollution source. The Hakanson potential ecological risk index was applied for assessing the status of sediment heavy metal enrichment and the result indicated that sediment dredging could reduce the extent of potential ecological risk. The risk index in different sites followed the order: X1 > D1 > D3 > X2 > D2, while the risk index in site X1 of Xukou Bay was higher than that in site D1 of East Taihu Lake. And the comprehensive ecological risk grades in sites X1 and D1 were in the moderate range, while the sites D2, D3 and X2 were low.

Shifts in the source and composition of dissolved organic matter in Southwest Greenland lakes along a regional hydro-climatic gradient

DEFF Research Database (Denmark)

Osburn, Christopher L.; Anderson, Nicholas J.; Stedmon, Colin A.

2018-01-01

Dissolved organic matter (DOM) concentration and quality were examined from Arctic lakes located in three clusters across south-west (SW) Greenland, covering the regional climatic gradient: cool, wet coastal zone; dry inland interior; and cool, dry ice-marginal areas. We hypothesized that differe...

Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002–2008

International Nuclear Information System (INIS)

Risch, Martin R.; Gay, David A.; Fowler, Kathleen K.; Keeler, Gerard J.; Backus, Sean M.; Blanchard, Pierrette; Barres, James A.; Dvonch, J. Timothy

2012-01-01

Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002–2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002–2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation. - Highlights: ► Data from 5 Hg and precipitation networks in the USA and Canada were combined for the first time. ► High-resolution maps and statistical trends tests were used for spatial and temporal data analysis. ► Some 7-year mean annual Hg concentrations exceeded a 12 ng per liter water-quality criterion. ► Small, localized decreases in Hg concentration were offset by increases in precipitation. ► Hg wet deposition was unchanged in the Great Lakes region and its subregions during 2002–2008. - Analysis of monitoring data from 5 networks in the USA and Canada determined that mercury wet deposition was unchanged in the North American Great Lakes region during 2002–2008.

Estimating Spring Condensation on the Great Lakes

Science.gov (United States)

Meyer, A.; Welp, L.

2017-12-01

The Laurentian Great Lakes region provides opportunities for shipping, recreation, and consumptive water use to a large part of the United States and Canada. Water levels in the lakes fluctuate yearly, but attempts to model the system are inadequate because the water and energy budgets are still not fully understood. For example, water levels in the Great Lakes experienced a 15-year low period ending in 2013, the recovery of which has been attributed partially to decreased evaporation and increased precipitation and runoff. Unlike precipitation, the exchange of water vapor between the lake and the atmosphere through evaporation or condensation is difficult to measure directly. However, estimates have been constructed using off-shore eddy covariance direct measurements of latent heat fluxes, remote sensing observations, and a small network of monitoring buoys. When the lake surface temperature is colder than air temperature as it is in spring, condensation is larger than evaporation. This is a relatively small component of the net annual water budget of the lakes, but the total amount of condensation may be important for seasonal energy fluxes and atmospheric deposition of pollutants and nutrients to the lakes. Seasonal energy fluxes determine, and are influenced by, ice cover, water and air temperatures, and evaporation in the Great Lakes. We aim to quantify the amount of spring condensation on the Great Lakes using the National Center for Atmospheric Prediction North American Regional Reanalysis (NCEP NARR) Data for Winter 2013 to Spring 2017 and compare the condensation values of spring seasons following high volume, high duration and low volume, low duration ice cover.

Cyanotoxins in arctic lakes of southwestern Greenland and the potential for toxin transfer within-lake and across the aquatic-terrestrial boundary

Science.gov (United States)

Trout-Haney, J. V.; Cottingham, K. L.

2015-12-01

Arctic lakes are often characterized as low-resource environments in which the autotrophic community is limited by factors such as nutrients, temperature, and light. Studies of cyanotoxins have traditionally focused on nutrient-rich lakes with conspicuous blooms, however toxigenic cyanobacteria are confined to neither high nutrient environments nor planktonic taxa. We quantified the occurrence of cyanotoxins across 19 arctic lakes of varying size and depth in the Kangerlussuaq region of southwestern Greenland. Whole lake water microcystins (MC) were detected in all lakes and ranged from low (100 ng/L) concentrations. Benthic colonial cyanobacteria of the genus Nostoc are a prominent feature of certain lakes in this region, with estimated densities ranging between 500 and >500,000 colonies per lake. MC were present in the tissue of Nostoc colonies (95% CI, 1638.9 - 3237.6 pg MC (g wet weight)-1) and were actively released by colonies into surrounding water in laboratory trials. These results highlight the potential importance of toxic benthic cyanobacteria in lake ecosystems. Further, we investigated the transfer of these cyanotoxins to other organisms in the lake as well as several mechanisms (i.e., emerging insects, aerosols) that may influence the movement of toxins into the terrestrial ecosystem. The presence and movement of cyanotoxins in the coupled terrestrial-aquatic ecosystem demonstrate that high-latitude lakes can support toxigenic cyanobacteria, and that we may be underestimating the potential for these systems to develop high levels of toxicity in the future.

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

Science.gov (United States)

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

2013-01-01

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

Temporal and spatial variability of frost-free seasons in the Great Lakes region of the United States

Science.gov (United States)

Lejiang Yu; Shiyuan Zhong; Xindi Bian; Warren E. Heilman; Jeffrey A. Andresen

2014-01-01

The frequency and timing of frost events and the length of the growing season are critical limiting factors in many human and natural ecosystems. This study investigates the temporal and spatial variability of the date of last spring frost (LSF), the date of first fall frost (FFF), and the length of the frost-free season (FFS) in the Great Lakes region of the United...

Accounting for inter-annual and seasonal variability in regionalization of hydrologic response in the Great Lakes basin

Science.gov (United States)

Kult, J. M.; Fry, L. M.; Gronewold, A. D.

2012-12-01

Methods for predicting streamflow in areas with limited or nonexistent measures of hydrologic response typically invoke the concept of regionalization, whereby knowledge pertaining to gauged catchments is transferred to ungauged catchments. In this study, we identify watershed physical characteristics acting as primary drivers of hydrologic response throughout the US portion of the Great Lakes basin. Relationships between watershed physical characteristics and hydrologic response are generated from 166 catchments spanning a variety of climate, soil, land cover, and land form regimes through regression tree analysis, leading to a grouping of watersheds exhibiting similar hydrologic response characteristics. These groupings are then used to predict response in ungauged watersheds in an uncertainty framework. Results from this method are assessed alongside one historical regionalization approach which, while simple, has served as a cornerstone of Great Lakes regional hydrologic research for several decades. Our approach expands upon previous research by considering multiple temporal characterizations of hydrologic response. Due to the substantial inter-annual and seasonal variability in hydrologic response observed over the Great Lakes basin, results from the regression tree analysis differ considerably depending on the level of temporal aggregation used to define the response. Specifically, higher levels of temporal aggregation for the response metric (for example, indices derived from long-term means of climate and streamflow observations) lead to improved watershed groupings with lower within-group variance. However, this perceived improvement in model skill occurs at the cost of understated uncertainty when applying the regression to time series simulations or as a basis for model calibration. In such cases, our results indicate that predictions based on long-term characterizations of hydrologic response can produce misleading conclusions when applied at shorter

Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife, NT, (Canada Region.

Directory of Open Access Journals (Sweden)

Adam James Houben

Full Text Available Gold mines in the Yellowknife, NT, region--in particular, the Giant Mine--operated from 1949-99, releasing 237,000 tonnes of waste arsenic trioxide (As2O3 dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing. Additionally, we demonstrate that underlying bedrock is not a significant source for the elevated concentrations in overlying surface waters. Aquatic arsenic (As concentrations are well above guidelines for drinking water (10 μg/L and protection for aquatic life (5 μg/L, ranging up to 136 μg/L in lakes within 4 km from the mine, to 2.0 μg/L in lakes 24 km away. High conversion ratios of methyl mercury were shown in lakes near the roaster stack as well, with MeHg concentrations reaching 44% of total mercury. The risk of elevated exposures by these metals is significant, as many lakes used for recreation and fishing near the City of Yellowknife are within this radius of elevated As and methyl Hg concentrations.

Unexpected stasis in a changing world: Lake nutrient and chlorophyll trends since 1990

Science.gov (United States)

Oliver, Samantha K.; Collins, Sarah M.; Soranno, Patricia A.; Wagner, Tyler; Stanley, Emily H.; Jones, John R.; Stow, Craig A.; Lottig, Noah R.

2017-01-01

The United States (U.S.) has faced major environmental changes in recent decades, including agricultural intensification and urban expansion, as well as changes in atmospheric deposition and climate—all of which may influence eutrophication of freshwaters. However, it is unclear whether or how water quality in lakes across diverse ecological settings has responded to environmental change. We quantified water quality trends in 2913 lakes using nutrient and chlorophyll (Chl) observations from the Lake Multi-Scaled Geospatial and Temporal Database of the Northeast U.S. (LAGOS-NE), a collection of preexisting lake data mostly from state agencies. LAGOS-NE was used to quantify whether lake water quality has changed from 1990 to 2013, and whether lake-specific or regional geophysical factors were related to the observed changes. We modeled change through time using hierarchical linear models for total nitrogen (TN), total phosphorus (TP), stoichiometry (TN:TP), and Chl. Both the slopes (percent change per year) and intercepts (value in 1990) were allowed to vary by lake and region. Across all lakes, TN declined at a rate of 1.1% year−1, while TP, TN:TP, and Chl did not change. A minority (7%–16%) of individual lakes had changing nutrients, stoichiometry, or Chl. Of those lakes that changed, we found differences in the geospatial variables that were most related to the observed change in the response variables. For example, TN and TN:TP trends were related to region-level drivers associated with atmospheric deposition of N; TP trends were related to both lake and region-level drivers associated with climate and land use; and Chl trends were found in regions with high air temperature at the beginning of the study period. We conclude that despite large environmental change and management efforts over recent decades, water quality of lakes in the Midwest and Northeast U.S. has not overwhelmingly degraded or improved.

Remotely Sensing Lake Water Volumes on the Inner Arctic Coastal Plain of Northern Alaska

Science.gov (United States)

Simpson, C. E.; Arp, C. D.; Jones, B. M.; Hinkel, K. M.; Carroll, M.; Smith, L. C.

2017-12-01

Thermokarst lake depth is controlled by the amount of excess ice in near-surface permafrost, with lake depths of about 1 - 3 m in areas of epigenetic permafrost and over 10 m in areas of syngenetic permafrost. An important exception to these general patterns is found on the inner Arctic Coastal Plain (ACP) of northern Alaska, where deep lakes occur in Pleistocene-aged, ground-ice poor sandy terrain. These lakes cover 20% of the currently inactive sand sheet and dune deposit (referred to as the Pleistocene Sand Sea) that comprises approximately 7000 km2 of the ACP. Surrounded by high and eroding bluffs, sand sea lakes lie in natural depressions and are characterized by wide, shallow littoral shelves and central troughs that are typically oriented NNW to SSE and can reach depths greater than 20 m. Despite their unique form and extensive coverage, these lakes have received little prior study and a literature gap remains regarding regional water storage. This research classifies sand sea lakes, estimates individual lake volume, and provides a first quantification of water storage in a region of the lake-dominated ACP. We measured bathymetric profiles in 19 sand sea lakes using a sonar recorder to capture various lake depth gradients. Bathymetric surveys collected by oil industry consultants, lake monitoring programs, and habitat studies serve as additional datasets. These field measured lake depth data points were used to classify Color Infrared Photography, WorldView-2 satellite imagery, and Landsat-OLI satellite imagery to develop a spectral depth-classification algorithm and facilitate the interpolation of the bathymetry for study lakes in the inner ACP. Finally, we integrate the remotely sensed bathymetry and imagery-derived lake surface area to estimate individual and regional-scale lake volume. In addition to the natural function of these lakes in water storage, energy balance, and habitat provision, the need for winter water supply to build ice roads for oil

Modeling lakes and reservoirs in the climate system

Science.gov (United States)

MacKay, M.D.; Neale, P.J.; Arp, C.D.; De Senerpont Domis, L. N.; Fang, X.; Gal, G.; Jo, K.D.; Kirillin, G.; Lenters, J.D.; Litchman, E.; MacIntyre, S.; Marsh, P.; Melack, J.; Mooij, W.M.; Peeters, F.; Quesada, A.; Schladow, S.G.; Schmid, M.; Spence, C.; Stokes, S.L.

2009-01-01

Modeling studies examining the effect of lakes on regional and global climate, as well as studies on the influence of climate variability and change on aquatic ecosystems, are surveyed. Fully coupled atmosphere-land surface-lake climate models that could be used for both of these types of study simultaneously do not presently exist, though there are many applications that would benefit from such models. It is argued here that current understanding of physical and biogeochemical processes in freshwater systems is sufficient to begin to construct such models, and a path forward is proposed. The largest impediment to fully representing lakes in the climate system lies in the handling of lakes that are too small to be explicitly resolved by the climate model, and that make up the majority of the lake-covered area at the resolutions currently used by global and regional climate models. Ongoing development within the hydrological sciences community and continual improvements in model resolution should help ameliorate this issue.

Global Scale Remote Sensing Monitoring of Endorheic Lake Systems

Science.gov (United States)

Scuderi, L. A.

2010-12-01

Semi-arid regions of the world contain thousands of endorheic lakes in large shallow basins. Due to their generally remote locations few are continuously monitored. Documentation of recent variability is essential to assessing how endorheic lakes respond to short-term meteorological conditions and longer-term decadal-scale climatic variability and is critical in determining future disturbance of hydrological regimes with respect to predicted warming and drying in the mid-latitudes. Short- and long-term departures from climatic averages, rapid environmental shifts and increased population pressures may result in significant fluctuations in the hydrologic budgets of these lakes and adversely impact endorheic lake/basin ecosystems. Information on flooding variability is also critical in estimating changes in P/E balances and on the production of exposed and easily deflated surfaces that may impact dust loading locally and regionally. In order to provide information on how these lakes respond we need to understand how entire systems respond hydrologically to different climatic inputs. This requires monitoring and analysis of regional to continental-scale systems. To date, this level of monitoring has not been achieved in an operational system. In order to assess the possibility of creating a global-scale lake inundation database we analyzed two contrasting lake systems in western North America (Mexico and New Mexico, USA) and China (Inner Mongolia). We asked two major questions: 1) is it possible to quickly and accurately quantify current lake inundation events in near real time using remote sensing? and, 2) is it possible to differentiate variable meteorological sources and resultant lake inundation responses using this type of database? With respect to these results we outline an automated lake monitoring approach using MODIS data and real-time processing systems that may provide future global monitoring capabilities.

Limnology and cyanobacterial diversity of high altitude lakes of ...

Indian Academy of Sciences (India)

Limnological data of four high altitude lakes from the cold desert region of Himachal Pradesh, India, has been correlated with cyanobacterial diversity. Physico-chemical characteristics and nutrient contents of the studied lakes revealed that Sissu Lake is mesotrophic while Chandra Tal, Suraj Tal and Deepak Tal are ...

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

Directory of Open Access Journals (Sweden)

Laijian Wang

2017-10-01

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

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes

Science.gov (United States)

Bacon, Linda C; Beauchene, Michael; Bednar, Karen E; Bissell, Edward G; Boudreau, Claire K; Boyer, Marvin G; Bremigan, Mary T; Carpenter, Stephen R; Carr, Jamie W; Christel, Samuel T; Claucherty, Matt; Conroy, Joseph D; Downing, John A; Dukett, Jed; Filstrup, Christopher T; Funk, Clara; Gonzalez, Maria J; Green, Linda T; Gries, Corinna; Halfman, John D; Hamilton, Stephen K; Hanson, Paul C; Henry, Emily N; Herron, Elizabeth M; Hockings, Celeste; Jackson, James R; Jacobson-Hedin, Kari; Janus, Lorraine L; Jones, William W; Jones, John R; Keson, Caroline M; King, Katelyn B S; Kishbaugh, Scott A; Lathrop, Barbara; Latimore, Jo A; Lee, Yuehlin; Lottig, Noah R; Lynch, Jason A; Matthews, Leslie J; McDowell, William H; Moore, Karen E B; Neff, Brian P; Nelson, Sarah J; Oliver, Samantha K; Pace, Michael L; Pierson, Donald C; Poisson, Autumn C; Pollard, Amina I; Post, David M; Reyes, Paul O; Rosenberry, Donald O; Roy, Karen M; Rudstam, Lars G; Sarnelle, Orlando; Schuldt, Nancy J; Scott, Caren E; Smith, Nicole J; Spinelli, Nick R; Stachelek, Joseph J; Stanley, Emily H; Stoddard, John L; Stopyak, Scott B; Stow, Craig A; Tallant, Jason M; Thorpe, Anthony P; Vanni, Michael J; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C; Webster, Katherine E; White, Jeffrey D; Wilmes, Marcy K; Yuan, Shuai

2017-01-01

Abstract Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states. LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600–12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales. PMID:29053868

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes.

Science.gov (United States)

Soranno, Patricia A; Bacon, Linda C; Beauchene, Michael; Bednar, Karen E; Bissell, Edward G; Boudreau, Claire K; Boyer, Marvin G; Bremigan, Mary T; Carpenter, Stephen R; Carr, Jamie W; Cheruvelil, Kendra S; Christel, Samuel T; Claucherty, Matt; Collins, Sarah M; Conroy, Joseph D; Downing, John A; Dukett, Jed; Fergus, C Emi; Filstrup, Christopher T; Funk, Clara; Gonzalez, Maria J; Green, Linda T; Gries, Corinna; Halfman, John D; Hamilton, Stephen K; Hanson, Paul C; Henry, Emily N; Herron, Elizabeth M; Hockings, Celeste; Jackson, James R; Jacobson-Hedin, Kari; Janus, Lorraine L; Jones, William W; Jones, John R; Keson, Caroline M; King, Katelyn B S; Kishbaugh, Scott A; Lapierre, Jean-Francois; Lathrop, Barbara; Latimore, Jo A; Lee, Yuehlin; Lottig, Noah R; Lynch, Jason A; Matthews, Leslie J; McDowell, William H; Moore, Karen E B; Neff, Brian P; Nelson, Sarah J; Oliver, Samantha K; Pace, Michael L; Pierson, Donald C; Poisson, Autumn C; Pollard, Amina I; Post, David M; Reyes, Paul O; Rosenberry, Donald O; Roy, Karen M; Rudstam, Lars G; Sarnelle, Orlando; Schuldt, Nancy J; Scott, Caren E; Skaff, Nicholas K; Smith, Nicole J; Spinelli, Nick R; Stachelek, Joseph J; Stanley, Emily H; Stoddard, John L; Stopyak, Scott B; Stow, Craig A; Tallant, Jason M; Tan, Pang-Ning; Thorpe, Anthony P; Vanni, Michael J; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C; Webster, Katherine E; White, Jeffrey D; Wilmes, Marcy K; Yuan, Shuai

2017-12-01

Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states.LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600-12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales. © The Author 2017. Published by Oxford University Press.

LAGOS-NE: a multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of US lakes

Science.gov (United States)

Soranno, Patricia A.; Bacon, Linda C.; Beauchene, Michael; Bednar, Karen E.; Bissell, Edward G.; Boudreau, Claire K.; Boyer, Marvin G.; Bremigan, Mary T.; Carpenter, Stephen R.; Carr, Jamie W.; Cheruvelil, Kendra S.; Christel, Samuel T.; Claucherty, Matt; Collins, Sarah M.; Conroy, Joseph D.; Downing, John A.; Dukett, Jed; Fergus, C. Emi; Filstrup, Christopher T.; Funk, Clara; Gonzalez, Maria J.; Green, Linda T.; Gries, Corinna; Halfman, John D.; Hamilton, Stephen K.; Hanson, Paul C.; Henry, Emily N.; Herron, Elizabeth M.; Hockings, Celeste; Jackson, James R.; Jacobson-Hedin, Kari; Janus, Lorraine L.; Jones, William W.; Jones, John R.; Keson, Caroline M.; King, Katelyn B.S.; Kishbaugh, Scott A.; Lapierre, Jean-Francois; Lathrop, Barbara; Latimore, Jo A.; Lee, Yuehlin; Lottig, Noah R.; Lynch, Jason A.; Matthews, Leslie J.; McDowell, William H.; Moore, Karen E.B.; Neff, Brian; Nelson, Sarah J.; Oliver, Samantha K.; Pace, Michael L.; Pierson, Donald C.; Poisson, Autumn C.; Pollard, Amina I.; Post, David M.; Reyes, Paul O.; Rosenberry, Donald; Roy, Karen M.; Rudstam, Lars G.; Sarnelle, Orlando; Schuldt, Nancy J.; Scott, Caren E.; Skaff, Nicholas K.; Smith, Nicole J.; Spinelli, Nick R.; Stachelek, Joseph J.; Stanley, Emily H.; Stoddard, John L.; Stopyak, Scott B.; Stow, Craig A.; Tallant, Jason M.; Tan, Pang-Ning; Thorpe, Anthony P.; Vanni, Michael J.; Wagner, Tyler; Watkins, Gretchen; Weathers, Kathleen C.; Webster, Katherine E.; White, Jeffrey D.; Wilmes, Marcy K.; Yuan, Shuai

2017-01-01

Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states.LAGOS-NE contains data for 51 101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 data modules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situ measurements of lake water quality for a subset of the lakes from the past 3 decades for approximately 2600–12 000 lakes depending on the variable. The database contains approximately 150 000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from 87 lake water quality data sets from federal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest and most comprehensive databases of its type because it includes both in situ measurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales.

The spatial scale for cisco recruitment dynamics in Lake Superior during 1978-2007

Science.gov (United States)

Rook, Benjamin J.; Hansen, Michael J.; Gorman, Owen T.

2012-01-01

The cisco Coregonus artedi was once the most abundant fish species in the Great Lakes, but currently cisco populations are greatly reduced and management agencies are attempting to restore the species throughout the basin. To increase understanding of the spatial scale at which density‐independent and density‐dependent factors influence cisco recruitment dynamics in the Great Lakes, we used a Ricker stock–recruitment model to identify and quantify the appropriate spatial scale for modeling age‐1 cisco recruitment dynamics in Lake Superior. We found that the recruitment variation of ciscoes in Lake Superior was best described by a five‐parameter regional model with separate stock–recruitment relationships for the western, southern, eastern, and northern regions. The spatial scale for modeling was about 260 km (range = 230–290 km). We also found that the density‐independent recruitment rate and the rate of compensatory density dependence varied among regions at different rates. The density‐independent recruitment rate was constant among regions (3.6 age‐1 recruits/spawner), whereas the rate of compensatory density dependence varied 16‐fold among regions (range = −0.2 to −2.9/spawner). Finally, we found that peak recruitment and the spawning stock size that produced peak recruitment varied among regions. Both peak recruitment (0.5–7.1 age‐1 recruits/ha) and the spawning stock size that produced peak recruitment (0.3–5.3 spawners/ha) varied 16‐fold among regions. Our findings support the hypothesis that the factors driving cisco recruitment operate within four different regions of Lake Superior, suggest that large‐scale abiotic factors are more important than small‐scale biotic factors in influencing cisco recruitment, and suggest that fishery managers throughout Lake Superior and the entire Great Lakes basin should address cisco restoration and management efforts on a regional scale in each lake.

FishVis, A regional decision support tool for identifying vulnerabilities of riverine habitat and fishes to climate change in the Great Lakes Region

Science.gov (United States)

Stewart, Jana S.; Covert, S. Alex; Estes, Nick J.; Westenbroek, Stephen M.; Krueger, Damon; Wieferich, Daniel J.; Slattery, Michael T.; Lyons, John D.; McKenna, James E.; Infante, Dana M.; Bruce, Jennifer L.

2016-10-13

Climate change is expected to alter the distributions and community composition of stream fishes in the Great Lakes region in the 21st century, in part as a result of altered hydrological systems (stream temperature, streamflow, and habitat). Resource managers need information and tools to understand where fish species and stream habitats are expected to change under future conditions. Fish sample collections and environmental variables from multiple sources across the United States Great Lakes Basin were integrated and used to develop empirical models to predict fish species occurrence under present-day climate conditions. Random Forests models were used to predict the probability of occurrence of 13 lotic fish species within each stream reach in the study area. Downscaled climate data from general circulation models were integrated with the fish species occurrence models to project fish species occurrence under future climate conditions. The 13 fish species represented three ecological guilds associated with water temperature (cold, cool, and warm), and the species were distributed in streams across the Great Lakes region. Vulnerability (loss of species) and opportunity (gain of species) scores were calculated for all stream reaches by evaluating changes in fish species occurrence from present-day to future climate conditions. The 13 fish species included 4 cold-water species, 5 cool-water species, and 4 warm-water species. Presently, the 4 cold-water species occupy from 15 percent (55,000 kilometers [km]) to 35 percent (130,000 km) of the total stream length (369,215 km) across the study area; the 5 cool-water species, from 9 percent (33,000 km) to 58 percent (215,000 km); and the 4 warm-water species, from 9 percent (33,000 km) to 38 percent (141,000 km).Fish models linked to projections from 13 downscaled climate models projected that in the mid to late 21st century (2046–65 and 2081–2100, respectively) habitats suitable for all 4 cold-water species and 4

An Integrated Approach for Understanding Anthropogenic and Climatic Impacts on Lakes: A Case study from Lake Iznik, Turkey

Science.gov (United States)

Derin, Y.; Milewski, A.; Fryar, A. E.; Schroeder, P.

2013-12-01

Lakes are among the most vital natural water resource, providing many environmental and economic advantages to a region. Unfortunately, many lakes are disappearing or continue to be polluted as industrial and agricultural practices increase to keep pace with rising populations. Lake Iznik, the biggest lake (approximately 300 km2) in the Marmara Region in Turkey, is a significant water resource as it provides opportunities for recreational activities, agriculture, industry, and water production for the region. However, rapid population growth combined with poor land management practices in this water basin has contributed to decreased water quality and water levels. As a result, Lake Iznik has switched from being Mesotrophic to Eutrophic in the past thirty years. This research aims to understand both the anthropogenic and climatic impacts on Lake Iznik. An integrated approach combining satellite remote sensing, hydrogeology, hydrologic modeling, and climatology was utilized to identify the source and timing responsible for the decline in water quality and quantity. Specifically, Landsat TM images from 1990, 2000, 2005, and 2010 were collected, processed, and analyzed for changes in landuse/landcover and surface area extent of Lake Iznik. Water level and water quality data (e.g. streamflow, lake level, pH, conductivity, total nitrogen, total dissolved solid etc.) collected from the General Directorate of State Hydraulic Works (DSI) from 1980-2012 were obtained from 4 stations and compared to the Landsat landuse mosaics. Meteorological data collected from Turkish State Meteorological Service from 1983-2012 were obtained from 3 stations (precipitation, temperature, atmospheric pressure, relative humidity, vapor pressure, wind speed and pan evaporation). A hydrologic model using MIKE21 was constructed to measure the change in streamflow and subsequent lake level as a result of changes in both land use and climate. Results have demonstrated the drop in water level from

Spatial co-distribution of neglected tropical diseases in the East African Great Lakes region: revisiting the justification for integrated control

Science.gov (United States)

Clements, Archie C. A.; Deville, Marie-Alice; Ndayishimiye, Onésime; Brooker, Simon; Fenwick, Alan

2010-01-01

Summary OBJECTIVE To determine spatial patterns of co-endemicity of schistosomiasis mansoni and the soil-transmitted helminths (STHs) Ascaris lumbricoides, Trichuris trichiura and hookworm in the Great Lakes region of East Africa, to help plan integrated neglected tropical disease programmes in this region. METHOD Parasitological surveys were conducted in Uganda, Tanzania, Kenya and Burundi in 28 213 children in 404 schools. Bayesian geostatistical models were used to interpolate prevalence of these infections across the study area. Interpolated prevalence maps were overlaid to determine areas of co-endemicity. RESULTS In the Great Lakes region, prevalence was 18.1% for Schistosoma mansoni, 50.0% for hookworm, 6.8% for A. lumbricoides and 6.8% for T. trichiura. Hookworm infection was ubiquitous, whereas S. mansoni, A. lumbricoides and T. trichiura were highly focal. Most areas were endemic (prevalence ≥10%) or hyperendemic (prevalence ≥50%) for one or more STHs, whereas endemic areas for schistosomiasis mansoni were restricted to foci adjacent large perennial water bodies. CONCLUSION Because of the ubiquity of hookworm, treatment programmes are required for STH throughout the region but efficient schistosomiasis control should only be targeted at limited high-risk areas. Therefore, integration of schistosomiasis with STH control is only indicated in limited foci in East Africa. PMID:20409287

Seismicity and seismotectonics of the Western Lake Ontario Region -relocation of the seismic events phase III

International Nuclear Information System (INIS)

Mohajer, A.A.

1995-12-01

Earthquake hazard analysis in Canada relies mainly on recorded earthquake data. The ability to record earthquakes of a given magnitude has varied considerably over time as has the accuracy of location determinations. Recomputation of earthquake locations has been suggested as a possible means of improving the existing data base for better definition of seismic sources. In this study, the locations of more than 50 small to moderate magnitude earthquakes (M≤5), in the western Lake Ontario region, were examined. Available seismograph records in the Record Centre of the National Archives of Canada were examined for events that occurred prior to 1978. The events recorded after this date showed increasing accuracy in their location determinations due to initiation and improvements of the Eastern Canada Telemetry Network (ECTN). Data compiled from the study are based on the relocated and/or selected events with the minimum travel time residuals at the Canadian and American stations. Except for a few scattered events in the south-central part of the Lake Ontario region, microearthquakes (M<3.5) cluster along or at the intersection of prominent aeromagnetic and gravity anomalies, within the Toronto-Hamilton Seismic Zone. This is indicative of certain seismotectonic relationships in this region. The depth distribution or the better located events show that a range of 5 to 20 km is dominant and, therefore, they are not near-surface stress relief phenomena. However, details of the structural manifestation of inferred seismogenic features need further ground truthing, backed by long term seismic monitoring. (author) 66 refs., 3 tabs., 6 figs

Spatiotemporal patterns of mercury accumulation in lake sediments of western North America

Science.gov (United States)

Drevnick, Paul; Cooke, Colin A.; Barraza, Daniella; Blais, Jules M.; Coale, Kenneth; Cumming, Brian F.; Curtis, Chris; Das, Biplob; Donahue, William F.; Eagles-Smith, Collin A.; Engstrom, Daniel R.; Fitzgerald, William F.; Furl, Chad V.; Gray, John R.; Hall, Roland I.; Jackson, Togwell A.; Laird, Kathleen R.; Lockhart, W. Lyle; Macdonald, Robie W.; Mast, M. Alisa; Mathieu, Callie; Muir, Derek C.G.; Outridge, Peter; Reinemann, Scott; Rothenberg, Sarah E.; Ruiz-Fernandex, Ana Carolina; St. Louis, V.L.; Sanders, Rhea; Sanei, Hamed; Skierszkan, Elliott; Van Metre, Peter C.; Veverica, Timothy; Wiklund, Johan A.; Wolfe, Brent B.

2016-01-01

For the Western North America Mercury Synthesis, we compiled mercury records from 165 dated sediment cores from 138 natural lakes across western North America. Lake sediments are accepted as faithful recorders of historical mercury accumulation rates, and regional and sub-regional temporal and spatial trends were analyzed with descriptive and inferential statistics. Mercury accumulation rates in sediments have increased, on average, four times (4×) from 1850 to 2000 and continue to increase by approximately 0.2 μg/m2 per year. Lakes with the greatest increases were influenced by the Flin Flon smelter, followed by lakes directly affected by mining and wastewater discharges. Of lakes not directly affected by point sources, there is a clear separation in mercury accumulation rates between lakes with no/little watershed development and lakes with extensive watershed development for agricultural and/or residential purposes. Lakes in the latter group exhibited a sharp increase in mercury accumulation rates with human settlement, stabilizing after 1950 at five times (5×) 1850 rates. Mercury accumulation rates in lakes with no/little watershed development were controlled primarily by relative watershed size prior to 1850, and since have exhibited modest increases (in absolute terms and compared to that described above) associated with (regional and global) industrialization. A sub-regional analysis highlighted that in the ecoregion Northwestern Forest Mountains, mercury deposited to watersheds is delivered to lakes. Research is warranted to understand whether mountainous watersheds act as permanent sinks for mercury or if export of “legacy” mercury (deposited in years past) will delay recovery when/if emissions reductions are achieved.

Ecological Sensitivity Evaluation of Tourist Region Based on Remote Sensing Image - Taking Chaohu Lake Area as a Case Study

Science.gov (United States)

Lin, Y.; Li, W. J.; Yu, J.; Wu, C. Z.

2018-04-01

Remote sensing technology is of significant advantages for monitoring and analysing ecological environment. By using of automatic extraction algorithm, various environmental resources information of tourist region can be obtained from remote sensing imagery. Combining with GIS spatial analysis and landscape pattern analysis, relevant environmental information can be quantitatively analysed and interpreted. In this study, taking the Chaohu Lake Basin as an example, Landsat-8 multi-spectral satellite image of October 2015 was applied. Integrated the automatic ELM (Extreme Learning Machine) classification results with the data of digital elevation model and slope information, human disturbance degree, land use degree, primary productivity, landscape evenness , vegetation coverage, DEM, slope and normalized water body index were used as the evaluation factors to construct the eco-sensitivity evaluation index based on AHP and overlay analysis. According to the value of eco-sensitivity evaluation index, by using of GIS technique of equal interval reclassification, the Chaohu Lake area was divided into four grades: very sensitive area, sensitive area, sub-sensitive areas and insensitive areas. The results of the eco-sensitivity analysis shows: the area of the very sensitive area was 4577.4378 km2, accounting for about 37.12 %, the sensitive area was 5130.0522 km2, accounting for about 37.12 %; the area of sub-sensitive area was 3729.9312 km2, accounting for 26.99 %; the area of insensitive area was 382.4399 km2, accounting for about 2.77 %. At the same time, it has been found that there were spatial differences in ecological sensitivity of the Chaohu Lake basin. The most sensitive areas were mainly located in the areas with high elevation and large terrain gradient. Insensitive areas were mainly distributed in slope of the slow platform area; the sensitive areas and the sub-sensitive areas were mainly agricultural land and woodland. Through the eco-sensitivity analysis of

[Land layout for lake tourism based on ecological restraint].

Science.gov (United States)

Wang, Jian-Ying; Li, Jiang-Feng; Zou, Li-Lin; Liu, Shi-Bin

2012-10-01

To avoid the decrease and deterioration of lake wetlands and the other ecological issues such as lake water pollution that were caused by the unreasonable exploration of lake tourism, a land layout for the tourism development of Liangzi Lake with the priority of ecological security pattern was proposed, based on the minimal cumulative resistance model and by using GIS technology. The study area was divided into four ecological function zones, i. e., core protection zone, ecological buffer zone, ecotone zone, and human activity zone. The core protection zone was the landscape region of ecological source. In the protection zone, new tourism land was forbidden to be increased, and some of the existing fundamental tourism facilities should be removed while some of them should be upgraded. The ecological buffer zone was the landscape region with resistance value ranged from 0 to 4562. In the buffer zone, expansion of tourism land should be forbidden, the existing tourism land should be downsized, and human activities should be isolated from ecological source by converting the human environment to the natural environment as far as possible. The ecotone zone was the landscape region with resistance value ranged from 4562 to 30797. In this zone, the existing tourism land was distributed in patches, tourism land could be expanded properly, and the lake forestry ecological tourism should be developed widely. The human activity zone was the landscape region with resistance value ranged from 30797 to 97334, which would be the key area for the land layout of lake tourism. It was suggested that the land layout for tourism with the priority of landscape ecological security pattern would be the best choice for the lake sustainable development.

Regionalisation for lake level simulation – the case of Lake Tana in the Upper Blue Nile, Ethiopia

Directory of Open Access Journals (Sweden)

T. H. M. Rientjes

2011-04-01

Full Text Available In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regression analyses to establish relations between model parameters and catchment characteristics.

A relatively small number of studies are presented on Lake Tana's water balance. In most studies the water balance is solved at monthly time step and the water balance is simply closed by runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments characteristics. For runoff modelling the HBV-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. We aim to assess the closure term of Lake Tana's water balance, to assess model parameter uncertainty and to evaluate effectiveness of a multi-objective model calibration approach to make hydrological modeling results more plausible.

For the gauged catchments, model performance is assessed by the Nash-Sutcliffe coefficient and Relative Volumetric Error and resulted in satisfactory to good performance for six, large catchments. The regional model is validated and indicated satisfactory to good performance in most cases. Results show that runoff from ungauged catchments is as large as 527 mm per year for the simulation period and amounts to approximately 30% of Lake Tana stream inflow. Results of daily lake level simulation over the simulation period 1994–2003 show a water balance closure term of 85 mm per year that accounts to 2.7% of the total lake inflow. Lake level

Changing climate in the Lake Superior region: a case study of the June 2012 flood and its effects on the western-lake water column

Science.gov (United States)

Minor, E. C.; Forsman, B.; Guildford, S. J.

2013-12-01

In Lake Superior, the world's largest freshwater lake by area, we are seeing annual surface-water temperature increases outpacing those of the overlying atmosphere. We are also seeing ever earlier onsets of water-column stratification (in data sets from the mid-1980s to the present). In Minnesota, including the Lake Superior watershed, precipitation patterns are also shifting toward fewer and more extreme storm events, such as the June 2012 solstice flood, which impacted the western Lake Superior basin. We are interested in how such climatological changes will affect nutrient and carbon biogeochemistry in Lake Superior. The lake is currently an oligotrophic system exhibiting light limitation of primary production in winter and spring, with summer primary production generally limited by phosphorus and sometimes co-limited by iron. Analyses in the western arm of Lake Superior showed that the June 2012 flood brought large amounts of sediment and colored dissolved organic matter (CDOM) from the watershed into the lake. There was initially a ~50-fold spike in the total phosphorus concentrations (and a 5 fold spike in soluble reactive phosphorus) in flood-impacted waters. This disappeared rapidly, in large part due to sediment settling and did not lead to an increase in chlorophyll concentrations at monitored sampling sites. Instead, lake phytoplankton appeared light limited by a surface lens of warm water enriched in CDOM that persisted for over a month after the flood event itself. Our observations highlight the need for continuing research on these complex in-lake processes in order to make accurate predictions about longer term impacts of these large episodic inputs in CDOM, sediment, and nutrient loading.

A catastrophic event in Lake Geneva region during the Early Bronze Age?

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Kremer, Katrina; Yrro, Blé; Marillier, François; Hilbe, Michael; Corboud, Pierre; Rachoud-Schneider, Anne-Marie; Girardclos, Stéphanie

2013-04-01

Similarly to steep oceanic continental margins, lake slopes can collapse, producing large sublacustrine landslides and tsunamis. Lake sediments are excellent natural archives of such mass movements and their study allows the reconstructions of these prehistoric events, such as the 563 AD large tsunami over Lake Geneva (Kremer et al, 2012). In Lake Geneva, more than 100 km of high-resolution seismic reflection profiles reveal the late Holocene sedimentation history. The seismic record shows a succession of five large lens-shaped seismic units (A to I), characterized by transparent/chaotic seismic facies with irregular lower boundaries, and interpreted as mass-movement deposits. These units are interbedded with parallel, continuous and strong amplitude reflections, interpreted as the 'background' lake sediments. The oldest dated mass movement (Unit D) covers a surface of 22 km2 in the deep basin, near the city of Lausanne. This deposit has an estimated minimum volume of 0.18 km3 and thus was very likely tsunamigenic (Kremer et al, 2012). A 12-m-long sediment core confirms the seismic interpretation of the mass movement unit and shows that the uppermost 3 m of Unit D are characterized by deformed hemipelagic sediments topped by a 5 cm thick turbidite. This deposit can be classified as a slump whose scar can be interpreted in the seismic data and visualized by multibeam bathymetry. This slump of Lausanne was likely triggered by an earthquake but a spontaneous slope collapse cannot be excluded (Girardclos et al, 2007). Radiocarbon dating of plant macro-remains reveals that the unit D happened during Early Bronze Age. Three other mass wasting deposits occurred during the same time period and may have been triggered during the same event, either by a single earthquake or by a tsunami generated by the slump of Lausanne. Although the exact trigger mechanism of the all these mass-wasting deposits remains unknown, a tsunami likely generated by this event may have affected the

[Suitable investigation method of exploration and suggestions for investigating Chinese materia medica resources from wetland and artificial water of Hongze Lake region].

Science.gov (United States)

Liu, Rui; Yan, Hui; Duan, Jin-Ao; Liu, Xing-Jian; Ren, Quan-Jin; Li, Hui-Wei; Bao, Bei-Hua; Zhang, Zhao-Hui

2016-08-01

According to the technology requirements of the fourth national survey of Chinese Materia Medica resources (pilot), suitable investigation method of exploration and suggestions for investigating Chinese Materia Medica resources was proposed based on the type of wetland and artificial water of Hongze Lake region. Environment of Hongze Lake and overview of wetland, present situation of ecology and vegetation and vegetation distribution were analyzed. Establishment of survey plan, selection of sample area and sample square and confirmation of representative water area survey plan were all suggested. The present study provide references for improving Chinese materia medica resources survey around Hongze Lake, and improving the technical specifications. It also provide references for investigating Chinese Materia Medica resources survey on similar ecological environment under the condition of artificial intervention. Copyright© by the Chinese Pharmaceutical Association.

Carbon accumulation and sequestration of lakes in China during the Holocene.

Science.gov (United States)

Wang, Mei; Chen, Huai; Yu, Zicheng; Wu, Jianghua; Zhu, Qiu'an; Peng, Changhui; Wang, Yanfen; Qin, Boqiang

2015-12-01

Understanding the responses of lake systems to past climate change and human activity is critical for assessing and predicting the fate of lake carbon (C) in the future. In this study, we synthesized records of the sediment accumulation from 82 lakes and of C sequestration from 58 lakes with direct organic C measurements throughout China. We also identified the controlling factors of the long-term sediment and C accumulation dynamics in these lakes during the past 12 ka (1 ka = 1000 cal yr BP). Our results indicated an overall increasing trend of sediment and C accumulation since 12 ka, with an accumulation peak in the last couple of millennia for lakes in China, corresponding to terrestrial organic matter input due to land-use change. The Holocene lake sediment accumulation rate (SAR) and C accumulation rate (CAR) averaged (mean ± SE) 0.47 ± 0.05 mm yr(-1) and 7.7 ± 1.4 g C m(-2)  yr(-1) in China, respectively, comparable to the previous estimates for boreal and temperate regions. The SAR for lakes in the East Plain of subtropical China (1.05 ± 0.28 mm yr(-1) ) was higher than those in other regions (P sequestration for lakes in China. We estimated the total amount of C burial in lakes of China as 8.0 ± 1.0 Pg C. This first estimation of total C storage and dynamics in lakes of China confirms the importance of lakes in land C budget in monsoon-influenced regions. © 2015 John Wiley & Sons Ltd.

Quantification of dissolved organic carbon (DOC) storage in lakes and reservoirs of mainland China.

Science.gov (United States)

Song, Kaishan; Wen, Zhidan; Shang, Yingxing; Yang, Hong; Lyu, Lili; Liu, Ge; Fang, Chong; Du, Jia; Zhao, Ying

2018-04-04

As a major fraction of carbon in inland waters, dissolved organic carbon (DOC) plays a crucial role in carbon cycling on a global scale. However, the quantity of DOC stored in lakes and reservoirs was not clear to date. In an attempt to examine the factors that determine the DOC storage in lakes and reservoirs across China, we assembled a large database (measured 367 lakes, and meta-analyzed 102 lakes from five limnetic regions; measured 144 reservoirs, and meta-analyzed 272 reservoirs from 31 provincial units) of DOC concentrations and water storages for lakes and reservoirs that are used to determine DOC storage in static inland waters. We found that DOC concentrations in saline waters (Mean/median ± S.D: 50.5/30.0 ± 55.97 mg/L) are much higher than those in fresh waters (8.1/5.9 ± 6.8 mg/L), while lake DOC concentrations (25.9/11.5 ± 42.04 mg/L) are much higher than those in reservoirs (5.0/3.8 ± 4.5 mg/L). In terms of lake water volume and DOC storage, the Tibet-Qinghai lake region has the largest water volume (552.8 km 3 ), 92% of which is saline waters, thus the largest DOC (13.39 Tg) is stored in these alpine lake region; followed by the Mengxin lake region, having a water volume of 99.4 km 3 in which 1.75 Tg DOC was stored. Compared to Mengxin lake region, almost the same amount of water was stored in East China lake region (91.9 km 3 ), however, much less DOC was stored in this region (0.43 Tg) due to the lower DOC concentration (Ave: 3.45 ± 2.68 mg/L). According to our investigation, Yungui and Northeast lake regions had water storages of 32.14 km 3 and 19.44 km 3 respectively, but relatively less DOC was stored in Yungui (0.13 Tg) than in Northeast lake region (0.19 Tg). Due to low DOC concentration in reservoirs, especially these large reservoirs having lower DOC concentration (V > 1.0 km 3 : 2.31 ± 1.48 mg/L), only 1.54 Tg was stored in a 485.1 km 3 volume of water contained

Water resources management in the urban agglomeration of the Lake Biwa region, Japan: An ecosystem services-based sustainability assessment.

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Chen, Xiaochen; Chen, Yuqing; Shimizu, Toshiyuki; Niu, Jia; Nakagami, Ken'ichi; Qian, Xuepeng; Jia, Baoju; Nakajima, Jun; Han, Ji; Li, Jianhua

2017-05-15

An innovative ecosystem services-based sustainability assessment was conducted in the important urban agglomeration of the Lake Biwa region, Japan, covering the time period from 1950 to 2014. A 22-indicator system was established that was based on the major ecosystem services of Lake Biwa and its water courses, i.e., provisioning services regarding aquatic products and water; regulating services regarding floods and water quality; cultural services regarding recreation and tourism, scientific research, and environmental education; and supporting services regarding biodiversity. First, changes in the eight ecosystem services were discussed together with the considerable experience and difficult lessons that can be drawn from the development trajectory. Next, with the indicators rearranged according to sustainability principles, the regional sustainability over the past six-plus decades was assessed. In general, this urban agglomeration has been progressing in terms of its sustainability, although economic and social development was achieved at the cost of environmental degradation in the past, and the current economic downturn is hurting the balanced development and integrated benefits. The results lead directly to recommendations for regional development, especially in terms of economic rejuvenation, from the perspective of improving management of Lake Biwa's water resources. Moreover, the relevant knowledge is educational and inspirational for other places in the world that are facing similar development issues. For example, the effective and even pioneering countermeasures that have been taken against environmental degradation, as well as the participation and collaboration of multiple stakeholders, could be useful as a model. Moreover, the study invites increased understanding of ecosystem vulnerability to anthropogenic devastation and emphasizes the priority of precautionary measures over countermeasures in the context of holistic urban planning and sustainable

Saline lakes of the glaciated Northern Great Plains

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Mushet, David M.

2011-01-01

Unless you have flown over the region or seen aerial photographs, it is hard to grasp the scale of the millions of lakes and wetlands that dot the prairie landscape of the glaciated Northern Great Plains (Figure 1). This region of abundant aquatic habitats within a grassland matrix provides for the needs of a wide diversity of wildlife species and has appropriately been deemed the "duck factory of North America." While the sheer number of lakes and wetlands within this area of the Northern Great Plains can be truly awe-inspiring, their diversity in terms of the chemical composition of their water adds an equally important component supporting biotic diversity and productivity. Water within these lakes and wetlands can range from extremely fresh with salinities approaching that of rainwater to hypersaline with salinity ten times greater than that of seawater. Additionally, while variation in salinity among these water bodies can be great, the ionic composition of lakes and wetlands with similar salinities can vary markedly, influencing the overall spatial and temporal diversity of the region's biota.

Factors Controlling Methane in Arctic Lakes of Southwest Greenland.

Science.gov (United States)

Northington, Robert M; Saros, Jasmine E

2016-01-01

We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the northern hemisphere (125 μmol L-1). The most important factors influencing methane in Greenland lakes included ionic composition (SO4, Na, Cl) and chlorophyll a in the water column. DOC concentrations were also related to methane, but the short length of the study likely underestimated the influence and timing of DOC on methane concentrations in the region. Atmospheric methane concentrations are increasing globally, with freshwater ecosystems in northern latitudes continuing to serve as potentially large sources in the future. Much less is known about how freshwater lakes in Greenland fit in the global methane budget compared to other, more well-studied areas of the Arctic, hence our work provides essential data for a more complete view of this rapidly changing region.

Lake Evaporation in a Hyper-Arid Environment, Northwest of China—Measurement and Estimation

OpenAIRE

Xiao Liu; Jingjie Yu; Ping Wang; Yichi Zhang; Chaoyang Du

2016-01-01

Lake evaporation is a critical component of the hydrological cycle. Quantifying lake evaporation in hyper-arid regions by measurement and estimation can both provide reliable potential evaporation (ET0) reference and promote a deeper understanding of the regional hydrological process and its response towards changing climate. We placed a floating E601 evaporation pan on East Juyan Lake, which is representative of arid regions’ terminal lakes, to measure daily evaporation and conducted simulta...

The Penokean orogeny in the Lake Superior region

Science.gov (United States)

Schulz, K.J.; Cannon, W.F.

2007-01-01

period of vertical faulting in the Archean basement and overlying Paleoproterozoic strata. This deformation is now known to have post-dated the terminal Penokean plutons by at least several tens of millions of years. Evidence of the Penokean orogen is now largely confined to the Lake Superior region. Comparisons with more recent orogens formed by similar plate tectonic processes implies that significant parts of a once more extensive Penokean orogen have been removed or overprinted by younger tectonic events. ?? 2007 Elsevier B.V. All rights reserved.

Increase of urban lake salinity by road deicing salt

International Nuclear Information System (INIS)

Novotny, Eric V.; Murphy, Dan; Stefan, Heinz G.

2008-01-01

Over 317,000 tonnes of road salt (NaCl) are applied annually for road deicing in the Twin Cities Metropolitan Area (TCMA) of Minnesota. Although road salt is applied to increase driving safety, this practice influences environmental water quality. Thirteen lakes in the TCMA were studied over 46 months to determine if and how they respond to the seasonal applications of road salt. Sodium and chloride concentrations in these lakes were 10 and 25 times higher, respectively, than in other non-urban lakes in the region. Seasonal salinity/chloride cycles in the lakes were correlated with road salt applications: High concentrations in the winter and spring, especially near the bottom of the lakes, were followed by lower concentrations in the summer and fall due to flushing of the lakes by rainfall runoff. The seasonal salt storage/flushing rates for individual lakes were derived from volume-weighted average chloride concentration time series. The rate ranged from 9 to 55% of a lake's minimum salt content. In some of the lakes studied salt concentrations were high enough to stop spring turnover preventing oxygen from reaching the benthic sediments. Concentrations above the sediments were also high enough to induce convective mixing of the saline water into the sediment pore water. A regional analysis of historical water quality records of 38 lakes in the TCMA showed increases in lake salinity from 1984 to 2005 that were highly correlated with the amount of rock salt purchased by the State of Minnesota. Chloride concentrations in individual lakes were positively correlated with the percent of impervious surfaces in the watershed and inversely with lake volume. Taken together, the results show a continuing degradation of the water quality of urban lakes due to application of NaCl in their watersheds

Evaluation of the crustal deformations in the northern region of Lake Nasser (Egypt) derived from 8 years of GPS campaign observations

Science.gov (United States)

Rayan, A.; Fernandes, R. M. S.; Khalil, H. A.; Mahmoud, S.; Miranda, J. M.; Tealab, A.

2010-04-01

The proper evaluation of crustal deformations in the Aswan (Egypt) region is crucial due to the existence of one major artificial structure: the Aswan High Dam. This construction induced the creation of one of the major artificial lakes: Lake Nasser, which has a surface area of about 5200 km 2 with a maximum capacity of 165 km 3. The lake is nearly 550 km long (more than 350 km within Egypt and the remainder in Sudan) and 35 km across at its widest point. Great attention has focused on this area after the November 14, 1981 earthquake ( ML = 5.7), with its epicenter southwest of the High Dam. In order to evaluate the present-day kinematics of the region, its relationship with increasing seismicity, and the possible influence of the Aswan High Dam operation, a network of 11 GPS sites was deployed in the area. This network has been reobserved every year since 2000 in campaign style. We present here the results of the analysis of the GPS campaign time-series. These time-series are already long enough to derive robust solutions for the motions of these stations. The computed trends are analyzed within the framework of the geophysical and geological settings of this region. We show that the observed displacements are significant, pointing to a coherent intraplate extensional deformation pattern, where some of the major faults (e.g., dextral strike-slip Kalabsha fault and normal Dabud fault) correspond to gradients of the surface deformation field. We also discuss the possible influence of the water load on the long-term deformation pattern.

Whiting in Lake Michigan

Science.gov (United States)

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

LIMNOLOGY, LAKE BASINS, LAKE WATERS

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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.

Landscape attributes driving avian influenza virus circulation in the Lake Alaotra region of Madagascar

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Laure Guerrini

2014-05-01

Full Text Available While the spatial pattern of the highly pathogenic avian influenza H5N1 virus has been studied throughout Southeast Asia, little is known on the spatial risk factors for avian influenza in Africa. In the present paper, we combined serological data from poultry and remotely sensed environmental factors in the Lake Alaotra region of Madagascar to explore for any association between avian influenza and landscape variables. Serological data from cross-sectional surveys carried out on poultry in 2008 and 2009 were examined together with a Landsat 7 satellite image analysed using supervised classification. The dominant landscape features in a 1-km buffer around farmhouses and distance to the closest water body were extracted. A total of 1,038 individual bird blood samples emanating from 241 flocks were analysed, and the association between avian influenza seroprevalence and these landcape variables was quantified using logistic regression models. No evidence of the presence of H5 or H7 avian influenza subtypes was found, suggesting that only low pathogenic avian influenza (LPAI circulated. Three predominant land cover classes were identified around the poultry farms: grassland savannah, rice paddy fields and wetlands. A significant negative relationship was found between LPAI seroprevalence and distance to the closest body of water. We also found that LPAI seroprevalence was higher in farms characterised by predominant wetlands or rice landscapes than in those surrounded by dry savannah. Results from this study suggest that if highly pathogenic avian influenza H5N1 virus were introduced in Madagascar, the environmental conditions that prevail in Lake Alaotra region may allow the virus to spread and persist.

Multiple climate regimes in an idealized lake-ice-atmosphere model

Science.gov (United States)

Sugiyama, Noriyuki; Kravtsov, Sergey; Roebber, Paul

2018-01-01

(occasionally wintertime ice-covered) deep-lake vs. shallow-lake regions, in terms of the corresponding characteristics of the forced transitions between colder and warmer lake regimes. Since the regime behavior in our models arises due to nonlinear dynamics rooted in the ice-albedo feedback, this feedback is also the root cause of the accelerated lake warming simulated by these models. In addition, our results imply that if Lake Superior eventually becomes largely ice-free (<10% maximum ice cover every winter) under continuing global warming, the surface warming trends of the deeper regions of the lake will become modest, similar to those of the shallower regions of the lake.

Landscapes of Lake Baikal: «To protect or to build» Town planning motivations of the stable development of the region

Directory of Open Access Journals (Sweden)

Andrei Bolshakov

2006-03-01

Full Text Available Building, planning, engineering facilities of the inhabited places of Lake Baikal and organization of the recreational areas for tourists, as well as organization of the particularly reserved natural territories should maintain everlastingly untouched the beauty and the cleanness, the natural diversity and the uniqueness of the nature of Lake Baikal, that makes it glorious and attracts tourists and inhabitants so much. Is it possible? And how to combine technical conditions of civilization, to which we have got used so much (energy supply, canalization, asphalt roads, automobile transport, oilpipelines, developed cities and villages, and aspiration of many investors, who would like to organize a profitable tourist business, together with the goal to protect the nature of Lake Baikal.To protect or to develop the landscapes of Lake Baikal, and which landscapes to urbanize and which to restore, and how to equip the developed territories, and how to maintain the protected natural landscapes–these questions compose a complex national task. Its accomplishment is firstly based on studying and maintaining the diversity of landscapes of the region and its importance as the global natural heritage. Secondly, the stable development of the region is possible only when solving the conflicts of landutilization motivations in a right way at the expense of building the rational network of the Baikal landscapes from the reserved to the urbanized ones.

Macroinvertebrates as indicators of fish absence in naturally fishless lakes

Science.gov (United States)

Schilling, Emily Gaenzle; Loftin, C.S.; Huryn, Alexander D.

2009-01-01

1. Little is known about native communities in naturally fishless lakes in eastern North America, a region where fish stocking has led to a decline in these habitats. 2. Our study objectives were to: (i) characterise and compare macroinvertebrate communities in fishless lakes found in two biophysical regions of Maine (U.S.A.): kettle lakes in the eastern lowlands and foothills and headwater lakes in the central and western mountains; (ii) identify unique attributes of fishless lake macroinvertebrate communities compared to lakes with fish and (iii) develop a method to efficiently identify fishless lakes when thorough fish surveys are not possible. 3. We quantified macroinvertebrate community structure in the two physiographic fishless lake types (n = 8 kettle lakes; n = 8 headwater lakes) with submerged light traps and sweep nets. We also compared fishless lake macroinvertebrate communities to those in fish-containing lakes (n = 18) of similar size, location and maximum depth. We used non-metric multidimensional scaling to assess differences in community structure and t-tests for taxon-specific comparisons between lakes. 4. Few differences in macroinvertebrate communities between the two physiographic fishless lake types were apparent. Fishless and fish-containing lakes had numerous differences in macroinvertebrate community structure, abundance, taxonomic composition and species richness. Fish presence or absence was a stronger determinant of community structure in our study than differences in physical conditions relating to lake origin and physiography. 5. Communities in fishless lakes were more speciose and abundant than in fish-containing lakes, especially taxa that are large, active and free-swimming. Families differing in abundance and taxonomic composition included Notonectidae, Corixidae, Gyrinidae, Dytiscidae, Aeshnidae, Libellulidae and Chaoboridae. 6. We identified six taxa unique to fishless lakes that are robust indicators of fish absence: Graphoderus

Composition and seasonal phenology of a nonindigenous root-feeding weevil (Coleoptera: Curculionidae) complex in northern hardwood forests in the Great Lakes Region

Science.gov (United States)

R. A. Pinski; W. J. Mattson; K. F. Raffa

2005-01-01

Phyllobius oblongus (L.), Polydrusus sericeus (Schaller), and Sciaphilus asperatus (Bonsdorff) comprise a complex of nonindigenous root-feeding weevils in northern hardwood forests of the Great Lakes region. Little is known about their detailed biology, seasonality, relative abundance, and distribution patterns....

ECOLOGICAL SENSITIVITY EVALUATION OF TOURIST REGION BASED ON REMOTE SENSING IMAGE – TAKING CHAOHU LAKE AREA AS A CASE STUDY

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Y. Lin

2018-04-01

Full Text Available Remote sensing technology is of significant advantages for monitoring and analysing ecological environment. By using of automatic extraction algorithm, various environmental resources information of tourist region can be obtained from remote sensing imagery. Combining with GIS spatial analysis and landscape pattern analysis, relevant environmental information can be quantitatively analysed and interpreted. In this study, taking the Chaohu Lake Basin as an example, Landsat-8 multi-spectral satellite image of October 2015 was applied. Integrated the automatic ELM (Extreme Learning Machine classification results with the data of digital elevation model and slope information, human disturbance degree, land use degree, primary productivity, landscape evenness , vegetation coverage, DEM, slope and normalized water body index were used as the evaluation factors to construct the eco-sensitivity evaluation index based on AHP and overlay analysis. According to the value of eco-sensitivity evaluation index, by using of GIS technique of equal interval reclassification, the Chaohu Lake area was divided into four grades: very sensitive area, sensitive area, sub-sensitive areas and insensitive areas. The results of the eco-sensitivity analysis shows: the area of the very sensitive area was 4577.4378 km2, accounting for about 37.12 %, the sensitive area was 5130.0522 km2, accounting for about 37.12 %; the area of sub-sensitive area was 3729.9312 km2, accounting for 26.99 %; the area of insensitive area was 382.4399 km2, accounting for about 2.77 %. At the same time, it has been found that there were spatial differences in ecological sensitivity of the Chaohu Lake basin. The most sensitive areas were mainly located in the areas with high elevation and large terrain gradient. Insensitive areas were mainly distributed in slope of the slow platform area; the sensitive areas and the sub-sensitive areas were mainly agricultural land and woodland

Hydroecological condition and potential for aquaculture in lakes of the arid region of Khorezm, Uzbekistan

Science.gov (United States)

Crootof, Africa; Mullabaev, Nodirbek; Saito, Laurel; Atwell, Lisa; Rosen, Michael R.; Bekchonova, Marhabo; Ginatullina, Elena; Scott, Julian; Chandra, Sudeep; Nishonov, Bakhriddin; Lamers, John P.A.; Fayzieva, Dilorom

2015-01-01

With >400 small (water resources to provide a local food supply could increase fish consumption while improving the rural economy. Hydroecological (biological and physical) and chemical characteristics (including legacy pesticides ΣDDT and ΣHCH) of four representative drainage lakes in Khorezm from 2006 to 2008 were analyzed for the lakes’ capability to support healthy fish populations. Lake characteristics were categorized as “optimal” (having little or no effect on growth and development), “tolerable” (corresponding to chronic or sub-lethal toxicity) and “lethal” (corresponding to acute toxicity). Results indicate that three lakes are likely well-suited for raising fish species, with water quality meeting World Bank aquaculture guidelines. However, the fourth lake often had salinity concentrations > optimal levels for local fish species. Pesticide concentrations in water of all four lakes were within tolerable aquaculture ranges. Although water ΣDDT concentrations were >optimal limits, results from chemical analysis of fish tissues and semi-permeable membrane devices indicated that study lake ΣDDT concentrations were not accumulating in fish or posing a human health threat. Land and water management to maintain adequate lake water quality are imperative for sustaining fish populations for human consumption.

Hydroecological condition and potential for aquaculture in lakes of the arid region of Khorezm, Uzbekistan

Science.gov (United States)

Crootof, Africa; Mullabaev, Nodirbek; Saito, Laurel; Atwell, Lisa; Rosen, Michael R.; Bekchonova, Marhabo; Ginatullina, Elena; Scott, Julian; Chandra, Sudeep; Nishonov, Bakhriddin; Lamers, John P.A.; Fayzieva, Dilorom

2015-01-01

With >400 small (resources to provide a local food supply could increase fish consumption while improving the rural economy. Hydroecological (biological and physical) and chemical characteristics (including legacy pesticides ΣDDT and ΣHCH) of four representative drainage lakes in Khorezm from 2006 to 2008 were analyzed for the lakes’ capability to support healthy fish populations. Lake characteristics were categorized as “optimal” (having little or no effect on growth and development), “tolerable” (corresponding to chronic or sub-lethal toxicity) and “lethal” (corresponding to acute toxicity). Results indicate that three lakes are likely well-suited for raising fish species, with water quality meeting World Bank aquaculture guidelines. However, the fourth lake often had salinity concentrations > optimal levels for local fish species. Pesticide concentrations in water of all four lakes were within tolerable aquaculture ranges. Although water ΣDDT concentrations were >optimal limits, results from chemical analysis of fish tissues and semi-permeable membrane devices indicated that study lake ΣDDT concentrations were not accumulating in fish or posing a human health threat. Land and water management to maintain adequate lake water quality are imperative for sustaining fish populations for human consumption.

Evaluation of Water Quality in Shallow Lakes, Case Study of Lake Uluabat

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Saadet İLERİ

2014-04-01

Full Text Available Lake Uluabat, located 20 km south of the Marmara Sea, between 42° 12' North latitude, 28° 40'East longitude and is located in the province of Bursa. The Lake is one of the richest lakes in terms of aquatic plants besides fish and bird populations in Turkey. In this study, water quality of the Lake was monitored from June 2008 to May 2009 during the 12 month period with the samples taken from 8 points in the lake and spatial and temporal variations of the parameters were examined. pH, temperature (T, electrical conductivity (EC, dissolved oxygen (DO, suspended solids (SS, secchi depth (SD, water level (WL, nitrate nitrogen (NO3-N, total nitrogen (TN, phosphate-phosphorus (PO4-P, total phosphorus (TP, alkalinity, chemical oxygen demand (COD and chlorophyll-a (Chl-a were the monitoring parameters. As a result, concentrations of the parameters were found at high levels especially the 1st, 4th, 5th, and 8th stations and temporally were found at high levels often in the summer. According to the results of analysis of variance, regional and temporal variations of all parameters were found important except SS and NO3-N

Conifer density within lake catchments predicts fish mercury concentrations in remote subalpine lakes

Science.gov (United States)

Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

2016-01-01

Remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited mercury through freshwater food webs, as well as for evaluating the relative importance of mercury loading versus landscape influences on mercury bioaccumulation. The increase in mercury deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in mercury emissions may propagate to changes in Hg bioaccumulation and ecological risk. We evaluated mercury concentrations in resident fish from 28 high-elevation, sub-alpine lakes in the Pacific Northwest region of the United States. Fish total mercury (THg) concentrations ranged from 4 to 438 ng/g wet weight, with a geometric mean concentration (±standard error) of 43 ± 2 ng/g ww. Fish THg concentrations were negatively correlated with relative condition factor, indicating that faster growing fish that are in better condition have lower THg concentrations. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. We used a hierarchal statistical approach to evaluate the relative importance of physiological, limnological, and catchment drivers of fish Hg concentrations. Our top statistical model explained 87% of the variability in fish THg concentrations among lakes with four key landscape and limnological variables: catchment conifer density (basal area of conifers within a lake's catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. Conifer density within a lake's catchment was the most important variable explaining fish THg concentrations across lakes, with THg concentrations differing by more than 400 percent across the forest density spectrum. These results illustrate the importance of landscape characteristics in controlling mercury bioaccumulation in fish.

Hulun Lake's ecological health and evaluation of its' eutrophication

Science.gov (United States)

Li, W.; Yang, W.; Wang, X.; Huang, J.; Sun, B.; Li, X.

2013-12-01

Hulun Lake is the largest lake in the north of china. The special geological location determines its important position in regional environmental protection. In terms of Hulun Lake's current situation, this paper chooses the indexes of lake system, lake structure and lake condition. Based on the calculation of these indexes and related theory , the evaluation standards of Hulun Lake's ecological healthy system are worked out. The author used Analytic Hierarchy Process to determine the weight of each indicator layer and criteria layer, and then applied fuzzy-pattern recognition model to calculate, finally, identifying the status of Hulun Lake according to the degrees of all levels. At the same time, the author used an integrated nutrition state index method to do the eutrophication assessment. Evaluation results show that the current status of Hulun Lake is healthy and it is in the moderate level of eutrophication.

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

Directory of Open Access Journals (Sweden)

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.

Evaluation of Sugar Maple Dieback in the Upper Great Lakes Region and Development of a Forest Health Youth Education Program

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Bal, Tara L.

2013-01-01

Sugar Maple, "Acer saccharum" Marsh., is one of the most valuable trees in the northern hardwood forests. Severe dieback was recently reported by area foresters in the western Upper Great Lakes Region. Sugar Maple has had a history of dieback over the last 100 years throughout its range and different variables have been identified as…

Modern processes of palynomorph deposition at lakes of the northern region of the Rio de Janeiro State, Brazil.

Science.gov (United States)

Luz, Cynthia F P da; Barth, Ortrud M; Silva, Cleverson G

2010-09-01

Palynological analysis of pollen, Pteridophyta spores and algae deposited in the superficial sediments at Lagoa de Cima and Lagoa do Campelo Lakes, located in the north of Rio de Janeiro state, was used to determine the spatial variation of the palynomorphs deposition. A total of 67 pollen types were identified at Lagoa de Cima, with an expressive contribution of regional arboreous taxa, hydrophytes and ruderal plants of the pastureland. The depositional pattern of palynomorphs depends on the fluvial leakage, the proximity of the local sedimentation to the inlet of the Imbé and Urubu Rivers and the bathymetry of lake bottom. The highest concentrations of palynomorphs were observed in the decentralized and less deeper area, without the interference of the northeastern wind. At Lagoa do Campelo, a total of 58 pollen types were identified, among which the majority of the pollen grains came from hydrophytes, with the highest concentrations found along the northeastern shore. The southeastern shore showed high percentages of pollen and spores with degraded exine and mechanical damage, due to the transport through the lake by the currents caused by the wind, confirmed by the depositional trend of damaged palinomorphs along the same direction as the prevailing winds.

Changes in the Global Hydrological Cycle: Lessons from Modeling Lake Levels at the Last Glacial Maximum

Science.gov (United States)

Lowry, D. P.; Morrill, C.

2011-12-01

Geologic evidence shows that lake levels in currently arid regions were higher and lakes in currently wet regions were lower during the Last Glacial Maximum (LGM). Current hypotheses used to explain these lake level changes include the thermodynamic hypothesis, in which decreased tropospheric water vapor coupled with patterns of convergence and divergence caused dry areas to become more wet and vice versa, the dynamic hypothesis, in which shifts in the jet stream and Inter-Tropical Convergence Zone (ITCZ) altered precipitation patterns, and the evaporation hypothesis, in which lake expansions are attributed to reduced evaporation in a colder climate. This modeling study uses the output of four climate models participating in phase 2 of the Paleoclimate Modeling Intercomparison Project (PMIP2) as input into a lake energy-balance model, in order to test the accuracy of the models and understand the causes of lake level changes. We model five lakes which include the Great Basin lakes, USA; Lake Petén Itzá, Guatemala; Lake Caçó, northern Brazil; Lake Tauca (Titicaca), Bolivia and Peru; and Lake Cari-Laufquen, Argentina. These lakes create a transect through the drylands of North America through the tropics and to the drylands of South America. The models accurately recreate LGM conditions in 14 out of 20 simulations, with the Great Basin lakes being the most robust and Lake Caçó being the least robust, due to model biases in portraying the ITCZ over South America. An analysis of the atmospheric moisture budget from one of the climate models shows that thermodynamic processes contribute most significantly to precipitation changes over the Great Basin, while dynamic processes are most significant for the other lakes. Lake Cari-Laufquen shows a lake expansion that is most likely attributed to reduced evaporation rather than changes in regional precipitation, suggesting that lake levels alone may not be the best indicator of how much precipitation this region

New lakes in de-glaciating high-mountain regions - a challenge for integrative research about hazard protection and sustainable use

Science.gov (United States)

Haeberli, W.

2012-12-01

As a consequence of rapid glacier vanishing, an increasing number of smaller and larger lakes are forming in high-mountain regions worldwide. Such new lakes can be touristic landscape attractions and may also represent interesting potentials for hydropower production. However, they more and more often come into existence at the foot of very large and steep icy mountain walls, which are progressively destabilizing due to changing surface and subsurface ice conditions. The probability of far-reaching flood and debris flow catastrophes caused by impact waves from large rock/ice avalanches into lakes may still appear to be small now but steadily increases for long time periods to come. Corresponding projects related to hazard protection and sustainable use should be combined in an integrative and participatory planning process. This planning process must start soon, because the development in nature is fast and most likely accelerating. Technical tools for creating the necessary scientific knowledge basis at local to regional scales exist and can be used. The location of future new lakes in topographic bed depressions of now still glacier-covered areas can be quite safely assessed on the basis of morphological criteria or by applying ice thickness estimates using digital terrain information. Models for ice-thickness estimates couple the depth to bedrock via the basal shear stress with the surface slope and provide a (relative) bed topography which is much more robust than the (absolute) value of the calculated ice thickness. Numerical models at various levels of sophistication can be used to simulate possible future glacier changes in order to establish the probable time of lake formation and the effects of glacier shrinking on runoff seasonality and water supply. The largest uncertainties thereby relate to the large uncertainties of (absolute) ice thickness and mass/energy fluxes at the surface (climate scenarios, precipitation and albedo changes, etc.). Combined

The importance of lake-specific characteristics for water quality across the continental United States.

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Read, Emily K; Patil, Vijay P; Oliver, Samantha K; Hetherington, Amy L; Brentrup, Jennifer A; Zwart, Jacob A; Winters, Kirsten M; Corman, Jessica R; Nodine, Emily R; Woolway, R Iestyn; Dugan, Hilary A; Jaimes, Aline; Santoso, Arianto B; Hong, Grace S; Winslow, Luke A; Hanson, Paul C; Weathers, Kathleen C

2015-06-01

Lake water quality is affected by local and regional drivers, including lake physical characteristics, hydrology, landscape position, land cover, land use, geology, and climate. Here, we demonstrate the utility of hypothesis testing within the landscape limnology framework using a random forest algorithm on a national-scale, spatially explicit data set, the United States Environmental Protection Agency's 2007 National Lakes Assessment. For 1026 lakes, we tested the relative importance of water quality drivers across spatial scales, the importance of hydrologic connectivity in mediating water quality drivers, and how the importance of both spatial scale and connectivity differ across response variables for five important in-lake water quality metrics (total phosphorus, total nitrogen, dissolved organic carbon, turbidity, and conductivity). By modeling the effect of water quality predictors at different spatial scales, we found that lake-specific characteristics (e.g., depth, sediment area-to-volume ratio) were important for explaining water quality (54-60% variance explained), and that regionalization schemes were much less effective than lake specific metrics (28-39% variance explained). Basin-scale land use and land cover explained between 45-62% of variance, and forest cover and agricultural land uses were among the most important basin-scale predictors. Water quality drivers did not operate independently; in some cases, hydrologic connectivity (the presence of upstream surface water features) mediated the effect of regional-scale drivers. For example, for water quality in lakes with upstream lakes, regional classification schemes were much less effective predictors than lake-specific variables, in contrast to lakes with no upstream lakes or with no surface inflows. At the scale of the continental United States, conductivity was explained by drivers operating at larger spatial scales than for other water quality responses. The current regulatory practice of using

Global relationships between phosphorus and chlorophyll-a in oxbow lakes

Science.gov (United States)

Belcon, A. U.; Bernhardt, E. S.; Fritz, S. C.; Baker, P. A.

2011-12-01

Traditional limnological studies have focused on extant, large and deep bodies of fresh water. For over 70 years a strong positive relationship between sestonic chlorophyll-a (Chl-a) and total phosphorus (TP) has been established in temperate lakes with phosphorus generally viewed as the most limiting factor to productivity (Deevey 1940, Schindler 1977). Over the last few decades however, investigations have expanded to include the examination of shallow lakes, particularly in terms of water quality, nutrient content and regime shifts between stable alternate states. Most of these studies, however, have focused on northern, high latitude regions where the lakes are typically postglacial, isolated and fed by small streams. Relatively little work has been done on oxbow lakes which are floodplain lakes and are semi or permanently connected to the river. Oxbow lakes have been shown to serve several important ecologic and economic functions including nurseries for young fish, feeding grounds for top aquatic predators and increasing the biodiversity of the landscape particularly in tropical regions of the world where high precipitation and large rivers have produced thousands of oxbow lakes. In many developing countries oxbow lakes are an important source of revenue through fishing. This study examined the relationship between nutrients and productivity in oxbow lakes globally through a wide-spread literature synthesis. Four hundred and twenty nine oxbow lakes were represented by 205 data points while 285 data points represented 156 non-floodplain lakes. Despite differences in latitude, lake size and climate we find that oxbow lakes globally have a significantly less steep slope in their TP/Chl relationship than non-floodplain lakes do indicating that the same amount of sestonic phosphorus results in lower productivity. Oxbow lakes (TP/Chl): r = 0.7676, slope = 0.7257, Non-floodplain lakes (TP/Chl): r = 0.8096, slope = 1.1309. We theorize that their connection to the

Great Lakes Environmental Research Laboratory

Data.gov (United States)

Federal Laboratory Consortium — NOAA-GLERL and its partners conduct innovative research on the dynamic environments and ecosystems of the Great Lakes and coastal regions to provide information for...

Sulphate deposition by precipitation into Lake Ontario

Energy Technology Data Exchange (ETDEWEB)

Shaw, R W; Whelpdale, D M

1973-01-01

Measurements of sulphate concentration in precipitation from individual snow storms of several hours duration in the western Lake Ontario region indicate that approximately 9-66 mg/M/sub 2/ of SO/sub 4//sup 2 -/ is being deposited into the lake per storm. This amount is up to several times more than daily average values over long periods found by other workers. Using a mean sulphate concentration of 4 mg/l and an annual accumulation of precipitation of 760 mm, the yearly sulphate deposition by precipitation is about 0.1% of the total mass of sulphate in the lake; however, more significantly, it is of the same order of magnitude as that discharged directly into the lake by industry.

EVALUATING THE REGIONAL PREDICTIVE CAPACITY OF A PROCESS-BASED MERCURY EXPOSURE MODEL (R-MCM) FOR LAKES ACROSS VERMONT AND NEW HAMPSHIRE, USA

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Regulatory agencies are confronted with a daunting task of developing fish consumption advisories for a large number of lakes and rivers with little resources. A feasible mechanism to develop region-wide fish advisories is by using a process-based mathematical model. One model of...

Using temporal coherence to determine the response to climate change in Boreal Shield lakes.

Science.gov (United States)

Arnott, Shelley E; Keller, Bill; Dillon, Peter J; Yan, Norman; Paterson, Michael; Findlay, David

2003-01-01

Climate change is expected to have important impacts on aquatic ecosystems. On the Boreal Shield, mean annual air temperatures are expected to increase 2 to 4 degrees C over the next 50 years. An important challenge is to predict how changes in climate and climate variability will impact natural systems so that sustainable management policies can be implemented. To predict responses to complex ecosystem changes associated with climate change, we used long-term biotic databases to evaluate how important elements of the biota in Boreal Shield lakes have responded to past fluctuations in climate. Our long-term records span a two decade period where there have been unusually cold years and unusually warm years. We used coherence analyses to test for regionally operating controls on climate, water temperature, pH, and plankton richness and abundance in three regions across Ontario: the Experimental Lakes Area, Sudbury, and Dorset. Inter-annual variation in air temperature was similar among regions, but there was a weak relationship among regions for precipitation. While air temperature was closely related to lake surface temperatures in each of the regions, there were weak relationships between lake surface temperature and richness or abundance of the plankton. However, inter-annual changes in lake chemistry (i.e., pH) were correlated with some biotic variables. In some lakes in Sudbury and Dorset, pH was dependent on extreme events. For example, El Nino related droughts resulted in acidification pulses in some lakes that influenced phytoplankton and zooplankton richness. These results suggest that there can be strong heterogeneity in lake ecosystem responses within and across regions.

Assessment of the Great Lakes Marine Renewable Energy Resources: Characterizing Lake Erie Surge, Seiche and Waves

Science.gov (United States)

Farhadzadeh, A.; Hashemi, M. R.

2016-02-01

Lake Erie, the fourth largest in surface area, smallest in volume and shallowest among the Great Lakes is approximately 400 km long and 90 km wide. Short term lake level variations are due to storm surge generated by high winds and moving pressure systems over the lake mainly in the southwest-northeast direction, along the lakes longitudinal axis. The historical wave data from three active offshore buoys shows that significant wave height can exceed 5 m in the eastern and central basins. The long-term lake level data show that storm surge can reach up to 3 m in eastern Lake Erie. Owing its shallow depth, Lake Erie frequently experiences seiching motions, the low frequency oscillations that are initiated by storm surge. The seiches whose first mode of oscillations has a period of nearly 14.2 hours can last from several hours to days. In this study, the Lake Erie potential for power generation, primarily using storm surge and seiche and also waves are assessed. Given the cyclic lake level variations due to storm-induced seiching, a concept similar to that of tidal range development is utilized to assess the potential of storm surge and seiche energy harvesting mechanisms for power generation. In addition, wave energy resources of the Lake is characterized -. To achieve these objectives, the following steps are taken : (1) Frequency of occurrence for extreme storm surge and wave events is determined using extreme value analysis such as Peak-Over-Threshold method for the long-term water level and wave data; (2) Spatial and temporal variations of wave height, storm surge and seiche are characterized. The characterization is carried out using the wave and storm surge outputs from numerical simulation of a number of historical extreme events. The coupled ADCIRC and SWAN model is utilized for the modeling; (3) Assessment of the potentials for marine renewable power generation in Lake Erie is made. The approach can be extended to the other lakes in the Great Lakes region.

Association of MICA gene polymorphisms with liver fibrosis in schistosomiasis patients in the Dongting Lake region

Energy Technology Data Exchange (ETDEWEB)

Gong, Zheng; Luo, Qi-Zhi; Lin, Lin [Department of Immunology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China); Su, Yu-Ping; Peng, Hai-Bo [Central Blood Bank in Yueyang, Yueyang, Hunan Province (China); Du, Kun; Yu, Ping [Department of Immunology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China); Wang, Shi-Ping [Key Laboratory of Schistosomiasis in Hunan, Department of Parasitology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China)

2012-03-02

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region.

Association of MICA gene polymorphisms with liver fibrosis in schistosomiasis patients in the Dongting Lake region

International Nuclear Information System (INIS)

Gong, Zheng; Luo, Qi-Zhi; Lin, Lin; Su, Yu-Ping; Peng, Hai-Bo; Du, Kun; Yu, Ping; Wang, Shi-Ping

2012-01-01

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region

Investigation of landscape and lake acidification relationships

Energy Technology Data Exchange (ETDEWEB)

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.

The altered ecology of Lake Christina: A record of regime shifts, land-use change, and management from a temperate shallow lake

International Nuclear Information System (INIS)

Theissen, Kevin M.; Hobbs, William O.; Hobbs, Joy M. Ramstack; Zimmer, Kyle D.; Domine, Leah M.; Cotner, James B.; Sugita, Shinya

2012-01-01

We collected two sediment cores and modern submerged aquatic plants and phytoplankton from two sub-basins of Lake Christina, a large shallow lake in west-central Minnesota, and used stable isotopic and elemental proxies from sedimentary organic matter to explore questions about the pre- and post-settlement ecology of the lake. The two morphologically distinct sub-basins vary in their sensitivities to internal and external perturbations offering different paleoecological information. The record from the shallower and much larger western sub-basin reflects its strong response to internal processes, while the smaller and deeper eastern sub-basin record primarily reflects external processes including important post-settlement land-use changes in the area. A significant increase in organic carbon accumulation (3–4 times pre-settlement rates) and long-term trends in δ 13 C, organic carbon to nitrogen ratios (C/N), and biogenic silica concentrations shows that primary production has increased and the lake has become increasingly phytoplankton-dominated in the post-settlement period. Significant shifts in δ 15 N values reflect land-clearing and agricultural practices in the region and support the idea that nutrient inputs have played an important role in triggering changes in the trophic status of the lake. Our examination of hydroclimatic data for the region over the last century suggests that natural forcings on lake ecology have diminished in their importance as human management of the lake increased in the mid-1900s. In the last 50 years, three chemical biomanipulations have temporarily shifted the lake from the turbid, algal-dominated condition into a desired clear water regime. Two of our proxies (δ 13 C and BSi) measured from the higher resolution eastern basin record responded significantly to these known regime shifts. -- Highlights: ► We explore the sediment geochemistry from Lake Christina's two distinct sub-basins. ► Our geochemical data show

A relative vulnerability estimation of flood disaster using data envelopment analysis in the Dongting Lake region of Hunan

Science.gov (United States)

Li, C.-H.; Li, N.; Wu, L.-C.; Hu, A.-J.

2013-07-01

The vulnerability to flood disaster is addressed by a number of studies. It is of great importance to analyze the vulnerability of different regions and various periods to enable the government to make policies for distributing relief funds and help the regions to improve their capabilities against disasters, yet a recognized paradigm for such studies seems missing. Vulnerability is defined and evaluated through either physical or economic-ecological perspectives depending on the field of the researcher concerned. The vulnerability, however, is the core of both systems as it entails systematic descriptions of flood severities or disaster management units. The research mentioned often has a development perspective, and in this article we decompose the overall flood system into several factors: disaster driver, disaster environment, disaster bearer, and disaster intensity, and take the interaction mechanism among all factors as an indispensable function. The conditions of flood disaster components are demonstrated with disaster driver risk level, disaster environment stability level and disaster bearer sensitivity, respectively. The flood system vulnerability is expressed as vulnerability = f(risk, stability, sensitivity). Based on the theory, data envelopment analysis method (DEA) is used to detail the relative vulnerability's spatiotemporal variation of a flood disaster system and its components in the Dongting Lake region. The study finds that although a flood disaster system's relative vulnerability is closely associated with its components' conditions, the flood system and its components have a different vulnerability level. The overall vulnerability is not the aggregation of its components' vulnerability. On a spatial scale, zones central and adjacent to Dongting Lake and/or river zones are characterized with very high vulnerability. Zones with low and very low vulnerability are mainly distributed in the periphery of the Dongting Lake region. On a temporal

Analysis of Suspended Particulate Matter and Its Drivers in Sahelian Ponds and Lakes by Remote Sensing (Landsat and MODIS: Gourma Region, Mali

Directory of Open Access Journals (Sweden)

Elodie Robert

2017-12-01

Full Text Available The Sahelian region is characterized by significant variations in precipitation, impacting water quantity and quality. Suspended particulate matter (SPM dynamics has a significant impact on inland water ecology and water resource management. In-situ data in this region are scarce and, consequently, the environmental factors triggering SPM variability are yet to be understood. This study addresses these issues using remote sensing optical data. Turbidity and SPM of the Agoufou Lake in Sahelian Mali were measured from October 2014 to present, providing a large range of `values (SPM ranging from 106 to 4178 mg/L. These data are compared to satellite reflectance from Landsat (ETM+, OLI and MODIS (MOD09GQ, MYD09GQ. For each of these sensors, a spectral band in the near infrared region is found to be well suited to retrieve turbidity and SPM, up to very high values (R2 = 0.70 seldom addressed by remote sensing studies. The satellite estimates are then employed to assess the SPM dynamics in the main lakes and ponds of the Gourma region and its links to environmental and anthropogenic factors. The main SPM seasonal peak is observed in the rainy season (June to September in relation to precipitation and sediment transport. A second important peak occurs during the dry season, highlighting the importance of resuspension mechanisms in maintaining high values of SPM. Three different periods are observed: first, a relatively low winds period in the early dry season, when SPM decreases rapidly due to deposition; then, a period of wind-driven resuspension in January‒March; and lastly, an SPM deposition period in April–May, when the monsoon replaces the winter trade wind. Overall, a significant increase of 27% in SPM values is observed between 2000 and 2016 in the Agoufou Lake. The significant spatio-temporal variability in SPM revealed by this study highlights the importance of high resolution optical sensors for continuous monitoring of water quality in

Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

Science.gov (United States)

Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

2016-06-01

Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Algo-bacterial communities of the Kulunda steppe (Altai region, Russia) soda lakes].

Science.gov (United States)

Samylina, O S; Sapozhnikov, F V; Gaĭnanova, O Iu; Riabova, A V; Nikitin, M A; Sorokin, D Iu

2015-01-01

The composition and macroscopic structure of the floating oxygenic phototrophic communities from Kulunda steppe soda lakes (Petukhovskoe sodovoe, Tanatara VI, and Gorchiny 3) was described based on the data of the 2011 and 2012 expeditions (Winogradsky Institute of Microbiology). The algo-bacterial community with a green alga Ctenocladus circinnatus as an edificator was the typical one. Filamentous Geitlerinema sp. and Nodosilinea sp. were the dominant cyanobacteria. Apart from C. circinnatus, the algological component of the community contained unicellular green algae Dunaliella viridis and cf. Chlorella minutissima, as well as diatoms (Anomeoneis sphaerophora, Brchysira brebissonii, Brachysira zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, Nitzschia communis, and Nitzschia sp.1). The latter have not been previously identified in the lakes under study. In all lakes, a considerable increase in salinity was found to result in changes in the composition and macroscopic structure of algo-bacterial communities.

Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors.

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Liu, Wenzhi; Li, Siyue; Bu, Hongmei; Zhang, Quanfa; Liu, Guihua

2012-03-01

Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial-temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegetation, all eutrophication parameters except chlorophyll-a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social-economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial wastewaters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region.

Tides and lake-level variations in the great Patagonian lakes: Observations, modelling and geophysical implications.

Science.gov (United States)

Marderwald, Eric; Richter, Andreas; Horwath, Martin; Hormaechea, Jose Luis; Groh, Andreas

2016-04-01

In Patagonia, the glacial-isostatic adjustment (GIA) to past ice-mass changes (Ivins & James 2004; Klemann et al. 2007) is of particular interest in the context of the determination of the complex regional rheology related to plate subduction in a triple-junction constellation. To further complicate the situation, GIA is overlaid with load deformation not only due to present ice mass changes but also due to water-level changes in the lakes surrounding the icefields and the ocean surrounding Patagonia. These elastic deformations affect the determination of glacial-isostatic uplift rates from GPS observations (Dietrich et al. 2010; Lange et al. 2014). Observations of lake tides and their comparison with the theoretical tidal signal have been used previously to validate predictions of ocean tidal loading and have revealed regional deviations from conventional global elastic earth models (Richter et al. 2009). In this work we investigate the tides and lake-level variations in Lago Argentino, Lago Viedma, Lago San Martín/O'Higgins and Lago Buenos Aires/General Carrera. This allows us to test, among other things, the validity of tidal loading models. We present pressure tide-gauge records from two sites in Lago Argentino extending over 2.5 years (Richter et al. 2015). These observations are complemented by lake-level records provided by the Argentine National Hydrometeorological Network. Based on these lake-level time series the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle exceeding 1 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. In Lago Argentino sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in these lakes are dominated by surface seiches reaching 20 cm in amplitude. A harmonic tidal analysis of the lake

Tributaries affect the thermal response of lakes to climate change

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Råman Vinnå, Love; Wüest, Alfred; Zappa, Massimiliano; Fink, Gabriel; Bouffard, Damien

2018-01-01

Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine tributaries, the Aare River and the Rhône River, and their respective downstream peri-alpine lakes: Lake Biel and Lake Geneva. We propagate regional atmospheric temperature effects into river discharge projections. These, together with anthropogenic heat sources, are in turn incorporated into simple and efficient deterministic models that predict future water temperatures, river-borne suspended sediment concentration (SSC), lake stratification and river intrusion depth/volume in the lakes. Climate-induced shifts in river discharge regimes, including seasonal flow variations, act as positive and negative feedbacks in influencing river water temperature and SSC. Differences in temperature and heating regimes between rivers and lakes in turn result in large seasonal shifts in warming of downstream lakes. The extent of this repressive effect on warming is controlled by the lakes hydraulic residence time. Previous studies suggest that climate change will diminish deep-water oxygen renewal in lakes. We find that climate-related seasonal variations in river temperatures and SSC shift deep penetrating river intrusions from summer towards winter. Thus potentially counteracting the otherwise negative effects associated with climate change on deep-water oxygen content. Our findings provide a template for evaluating the response of similar hydrologic systems to on-going climate change.

Tributaries affect the thermal response of lakes to climate change

Directory of Open Access Journals (Sweden)

L. Råman Vinnå

2018-01-01

Full Text Available Thermal responses of inland waters to climate change varies on global and regional scales. The extent of warming is determined by system-specific characteristics such as fluvial input. Here we examine the impact of ongoing climate change on two alpine tributaries, the Aare River and the Rhône River, and their respective downstream peri-alpine lakes: Lake Biel and Lake Geneva. We propagate regional atmospheric temperature effects into river discharge projections. These, together with anthropogenic heat sources, are in turn incorporated into simple and efficient deterministic models that predict future water temperatures, river-borne suspended sediment concentration (SSC, lake stratification and river intrusion depth/volume in the lakes. Climate-induced shifts in river discharge regimes, including seasonal flow variations, act as positive and negative feedbacks in influencing river water temperature and SSC. Differences in temperature and heating regimes between rivers and lakes in turn result in large seasonal shifts in warming of downstream lakes. The extent of this repressive effect on warming is controlled by the lakes hydraulic residence time. Previous studies suggest that climate change will diminish deep-water oxygen renewal in lakes. We find that climate-related seasonal variations in river temperatures and SSC shift deep penetrating river intrusions from summer towards winter. Thus potentially counteracting the otherwise negative effects associated with climate change on deep-water oxygen content. Our findings provide a template for evaluating the response of similar hydrologic systems to on-going climate change.

Eutrophication monitoring for Lake Superior's Chequamegon ...

Science.gov (United States)

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading relate to observed chlorophyll concentrations. Sampling included ship-based water samples combined with vertical CTD casts, continuous in situ towing and data collected from an autonomous underwater glider. Sampling was conducted during June, July and September. The glider collected regional data as part of three extended missions in Lake Superior over the same periods. During the study, two significant storm events impacted the western end of Lake Superior; the first occurred during July 11-12, with 8-10 inches of rain in 24hrs, and the second on July 21 with winds in excess of 161 km/h. Using GIS software, we organized these diverse temporal data sets along a continuous time line with temporally coincident Modis Satellite data to visualize surface sediment plumes in relation to water quality measurements. Preliminary results suggest that both events impacted regional water quality, and that nearshore physical forces (upwelling and currents) influenced the spatial variability. Results comparing in situ measures with remotely sensed images will be discussed. not applicable

Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

International Nuclear Information System (INIS)

Korosi, J.B.; Irvine, G.; Skierszkan, E.K.; Doyle, J.R.; Kimpe, L.E.; Janvier, J.; Blais, J.M.

2013-01-01

The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies. -- Highlights: •In-situ bitumen extraction linked to rise in alkyl PAHs in one of two study lakes. •Alkyl PAHs elevated in two soil samples. •PAH contamination likely related to effluent sources, not atmospheric deposition. -- PAHs in sediments and soils were generally low in areas adjacent to in-situ bitumen extraction rigs in the Cold Lake Alberta oil sands, but evidence of localized contamination at some sites was evident

Sediment lithostratigraphy and past changes in sedimentary environment in isolated lakes in Satakunta region; Sedimenttistratigrafia ja sedimentaatioympaeristoen muutokset Itaemerestae kuroutuneissa jaervissae Satakunnassa

Energy Technology Data Exchange (ETDEWEB)

Ojala, A.E.K. [GTK Geological Survey of Finland, Espoo (Finland)

2011-12-15

The purpose of the present study was to investigate lacustrine sediment sections in lakes isolated from the Baltic Sea basin and appearing in Satakunta region. One of the aims was to characterize their sediment composition and structures (sediment lithostratigraphy) and to describe their past and present sedimentary environment. Altogether, 8 lakes were selected for the study based on their variable appearance and catchment environmental conditions, i.e. properties such as lake shape, size, and morphometry, as well as altitude and geology of the drainage basin. The primary research methods applied included use of ground penetrating radar, sediment coring and physical sedimentological applications. Sediment erosion, transportation and deposition (re-deposition) are significant but often slowly-appearing processes in lacustrine environment, such as the one presently studied. The rate of erosion and sediment yield depend primarily on water depth in different parts of a lake, wind and current action, and hydrological (palaeohydrological) changes. All the presently studied sediment sections were characterized by erosion and redeposition horizons. However, this is not surprising considering their isolation history from the Baltic Sea basin and current rather shallow nature. All presently studied lakes contained 2-8 meters thick section of post-glacial sediments. Being rather shallow and filled with sediments, these lakes were considered to be prone to erosion by wind and wave actions as well as sediment re-deposition. Some of the presently studied sediment sections were characterized by 10 to 50 cm thick (sandy) erosion horizons in their type-stratigraphies. However, sections were not discovered to contain massive discontinuity surfaces that would indicate fault-type sediment structures during the past 8000 years. Neither did the ground penetrating radar data show significant faults. (orig.)

The evolution of a thermokarst-lake landscape: Late Quaternary permafrost degradation and stabilization in interior Alaska

Science.gov (United States)

Edwards, Mary E.; Grosse, Guido; Jones, Benjamin M.; McDowell, Patricia F.

2016-01-01

Thermokarst processes characterize a variety of ice-rich permafrost terrains and often lead to lake formation. The long-term evolution of thermokarst landscapes and the stability and longevity of lakes depend upon climate, vegetation and ground conditions, including the volume of excess ground ice and its distribution. The current lake status of thermokarst-lake landscapes and their future trajectories under climate warming are better understood in the light of their long-term development. We studied the lake-rich southern marginal upland of the Yukon Flats (northern interior Alaska) using dated lake-sediment cores, observations of river-cut exposures, and remotely-sensed data. The region features thick (up to 40 m) Quaternary deposits (mainly loess) that contain massive ground ice. Two of three studied lakes formed ~ 11,000–12,000 cal yr BP through inferred thermokarst processes, and fire may have played a role in initiating thermokarst development. From ~ 9000 cal yr BP, all lakes exhibited steady sedimentation, and pollen stratigraphies are consistent with regional patterns. The current lake expansion rates are low (0 to drainage, nor of multiple lake generations within a basin. However, LiDAR images reveal linear “corrugations” (> 5 m amplitude), deep thermo-erosional gullies, and features resembling lake drainage channels, suggesting that highly dynamic surface processes have previously shaped the landscape. Evidently, widespread early Holocene permafrost degradation and thermokarst lake initiation were followed by lake longevity and landscape stabilization, the latter possibly related to establishment of dense forest cover. Partial or complete drainage of three lakes in 2013 reveals that there is some contemporary landscape dynamism. Holocene landscape evolution in the study area differs from that described from other thermokarst-affected regions; regional responses to future environmental change may be equally individualistic.

vegetation of the koobi fora region northeast of lake turkana

African Journals Online (AJOL)

Dale, I.R. & P.J. Greenway (1961). Kenya Trees and Shrubs. ... Holocene wet-dry transition recorded in palaeo-shorelines of Lake Turkana, northern. Kenya Rift. Earth and ... Integrated Project on Arid Lands Technical Paper. Number D-3.

Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming.

Science.gov (United States)

Walter, K M; Zimov, S A; Chanton, J P; Verbyla, D; Chapin, F S

2006-09-07

Large uncertainties in the budget of atmospheric methane, an important greenhouse gas, limit the accuracy of climate change projections. Thaw lakes in North Siberia are known to emit methane, but the magnitude of these emissions remains uncertain because most methane is released through ebullition (bubbling), which is spatially and temporally variable. Here we report a new method of measuring ebullition and use it to quantify methane emissions from two thaw lakes in North Siberia. We show that ebullition accounts for 95 per cent of methane emissions from these lakes, and that methane flux from thaw lakes in our study region may be five times higher than previously estimated. Extrapolation of these fluxes indicates that thaw lakes in North Siberia emit 3.8 teragrams of methane per year, which increases present estimates of methane emissions from northern wetlands (< 6-40 teragrams per year; refs 1, 2, 4-6) by between 10 and 63 per cent. We find that thawing permafrost along lake margins accounts for most of the methane released from the lakes, and estimate that an expansion of thaw lakes between 1974 and 2000, which was concurrent with regional warming, increased methane emissions in our study region by 58 per cent. Furthermore, the Pleistocene age (35,260-42,900 years) of methane emitted from hotspots along thawing lake margins indicates that this positive feedback to climate warming has led to the release of old carbon stocks previously stored in permafrost.

Patterns in the Physical, Chemical, and Biological Composition of Icelandic Lakes and the Dominant Factors Controlling Variability Across Watersheds

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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

Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska

Science.gov (United States)

Jones, Benjamin M.; Grosse, G.; Arp, C.D.; Jones, M.C.; Walter, Anthony K.M.; Romanovsky, V.E.

2011-01-01

Quantifying changes in thermokarst lake extent is of importance for understanding the permafrost-related carbon budget, including the potential release of carbon via lake expansion or sequestration as peat in drained lake basins. We used high spatial resolution remotely sensed imagery from 1950/51, 1978, and 2006/07 to quantify changes in thermokarst lakes for a 700 km2 area on the northern Seward Peninsula, Alaska. The number of water bodies larger than 0.1 ha increased over the entire observation period (666 to 737 or +10.7%); however, total surface area decreased (5,066 ha to 4,312 ha or -14.9%). This pattern can largely be explained by the formation of remnant ponds following partial drainage of larger water bodies. Thus, analysis of large lakes (>40 ha) shows a decrease of 24% and 26% in number and area, respectively, differing from lake changes reported from other continuous permafrost regions. Thermokarst lake expansion rates did not change substantially between 1950/51 and 1978 (0.35 m/yr) and 1978 and 2006/07 (0.39 m/yr). However, most lakes that drained did expand as a result of surface permafrost degradation before lateral drainage. Drainage rates over the observation period were stable (2.2 to 2.3 per year). Thus, analysis of decadal-scale, high spatial resolution imagery has shown that lake drainage in this region is triggered by lateral breaching and not subterranean infiltration. Future research should be directed toward better understanding thermokarst lake dynamics at high spatial and temporal resolution as these systems have implications for landscape-scale hydrology and carbon budgets in thermokarst lake-rich regions in the circum-Arctic.

Potentially dangerous glacial lakes in Kyrgyzstan - Research overview of 2004-2015

Science.gov (United States)

Jansky, Bohumir; Yerokhin, Sergey; Sobr, Miroslav; Engel, Zbynek; Cerny, Michal; Falatkova, Kristyna; Kocum, Jan; Benes, Vojtech

2016-04-01

Global warming causes intensive melting and retreat of glaciers in most of high mountains all over the world. This process is also evident in the mountain regions of central Tien Shan. Glacier melt water affects changes in hydrological regime of water streams and causes overfilling of high mountain lake basins. The dams of many lakes are very unstable and can burst open. To determine the degree of such risk, it is necessary to analyse the genesis of lakes, to characterize the morphology of the lake basins and to know the particularities of their hydrological regime. According to the latest inventory within territory of Kyrgyzstan, a total of 1328 lakes have been identified as potentially dangerous, 12 lakes are considered as currently dangerous, other 25 feature high potential hazard. Since 1952 more than 70 disastrous cases of lake outburst have been registered. The hazardous alpine lakes are studied in Kyrgyzstan systematically since 1966. Since 2004, Czech-Kyrgyz research team has been operating in Kyrgyzstan in the field of dangerous glacial lakes. Projects were focused primarily on high-mountain glacial lakes risk assessment, propositions of risk mitigation measures, establishment of permanent research station near one of the studied glacier complexes, preparation of risk analysis for selected endangered valleys, evaluation of climatic and hydrological data and glacier development within observed regions. The most significant portion of data and information has been gathered during field work, complemented by satellite image analysis and surveillance flights over the monitored sites.

Sedimentation rates and depositional processes in Lake Superior from 210Pb geochronology

International Nuclear Information System (INIS)

Evans, J.E.; Johnson, T.C.; Alexander, E.C. Jr.; Lively, R.S.; Eisenreich, S.J.

1981-01-01

Sedimentation rates range from 0.01 to 0.32 cm/yr in 17 sediment box cores from Lake Superior, as determined by 210 Pb geochronology. Shoreline erosion and resuspension of nearshore sediments causes moderate to high (0.05-0.11 cm/yr) sedimentation rates in the western arm of Lake Superior. Sedimentation rates are very high (> 0.15 cm/yr) in marginal bays adjoining Lake Superior; and moderate to very high (0.07-0.19 cm/yr) in open lake regions adjacent to marginal bays. Resuspension of nearshore and shoal top sediments in southern and southeastern Lake Superior by storms is responsible for depositional anomalies in 210 Pb profiles corresponding to 1905, 1916-1918, and 1940 storms. Sedimentation rates are very low (0.01-0.03 cm/yr) in the central basins due to isolation from sediment sources. These data indicate that sedimentation rates and processes vary significantly in different regions of Lake Superior. The sedimentation rates provided by this study, in conjunction with previously-reported sedimentation rates, yield a better understanding of the Lake Superior depositional environment

The International Conference on the Great Lakes Region and the implementation of the Ezulwini Consensus: Challenges and prospects

Directory of Open Access Journals (Sweden)

Shirambere P. Tunamsifu

2017-07-01

Full Text Available This article is evaluative assessing the implementation of the Ezulwini Consensus by the International Conference on the Great Lakes Region (ICGLR. In early April 2012, a mutiny started in the eastern part of the Democratic Republic of the Congo (DRC, resulting in the creation of the rebel group known as the Mouvement du 23 Mars (M23. The spread of M23 constituted a serious threat to peace, security and stability in the entire African Great Lakes region. On the basis of the Ezulwini Consensus, which emphasises that regional organisations in areas of proximity to conflicts should be empowered to take action, the ICGLR resolved to intervene. Through several summits attempting to find a home-grown solution, the ICGLR faced two main challenges in implementing the Ezulwini Consensus. The first was related to the lack of actions and sanctions against member states that violated fundamental principles and the second was related to the lack of neutrality of the chairperson of the ICGLR during the dialogue between the government of the DRC and M23. The intervention of the ICGLR is important, but in such circumstances, it is crucial that member states demonstrate their political will to respect fundamental principles and sanction members that allegedly ignore these principles. In the mediation process, where there is sufficient evidence to indicate that a member state is allegedly providing support to rebel groups that are destabilising another member state, it is important that the ICGLR adopt a policy of requesting such a country to avoid taking the lead in or mediating the conflict. However, when regional organisations in areas of conflict face such challenges, the African Union must take responsibility for comediating or sending African experts to resolve the conflict impartially.

Processed products of termites and lake flies: improving ...

African Journals Online (AJOL)

The lake region is endowed with plenty of edible insects. Edible insects can provide partial solution to food insecurity. The aim of this project was to promote entomophagy for food security by adding value to termites and lake flies, enhancing taste and preference of edible insects, and improving shelf life of edible insect ...

Characteristics of organic phosphorus fractions in different trophic sediments of lakes from the middle and lower reaches of Yangtze River region and Southwestern Plateau, China

International Nuclear Information System (INIS)

Zhang Runyu; Wu Fengchang; Liu Congqiang; Fu Pingqing; Li Wen; Wang Liying; Liao Haiqing; Guo Jianyang

2008-01-01

In this study, the characteristics of organic phosphorus (P o ) fractions in sediments of six lakes from the middle and lower reaches of Yangtze River region and Southwestern China Plateau, China were investigated using a soil P o fractionation scheme, and the relationships between P o , inorganic phosphorus (P i ) and pollution status were also discussed. The results show that the rank order of P o fractions was: residual P o > HCl-P o > fulvic acid-P > humic acid-P > NaHCO 3 -P o , with their average relative proportion 8.7:4.6:3.2:2.1:1.0. P o fractions, especially nonlabile P o , were significantly correlated with organic matter, P o and NaOH-P i . Different distribution patterns of P fractions were observed in those two different regions. P o fractions in the heavily polluted sediments were higher than those in moderately and no polluted sediments, it is suggested that P o should be paid more attention in the lake eutrophication investigation. - Organic phosphorus fractions in sediments from 6 different trophic Chinese lakes were characterized using an improved fractionation scheme

Lake sediments as natural seismographs: Earthquake-related deformations (seismites) in central Canadian lakes

Science.gov (United States)

Doughty, M.; Eyles, N.; Eyles, C. H.; Wallace, K.; Boyce, J. I.

2014-11-01

Central Canada experiences numerous intraplate earthquakes but their recurrence and source areas remain obscure due to shortness of the instrumental and historic records. Unconsolidated fine-grained sediments in lake basins are 'natural seismographs' with the potential to record ancient earthquakes during the last 10,000 years since the retreat of the Laurentide Ice Sheet. Many lake basins are cut into bedrock and are structurally-controlled by the same Precambrian basement structures (shear zones, terrane boundaries and other lineaments) implicated as the source of ongoing mid-plate earthquake activity. A regional seismic sub-bottom profiling of lakes Gull, Muskoka, Joseph, Rousseau, Ontario, Wanapitei, Fairbanks, Vermilion, Nipissing, Georgian Bay, Mazinaw, Simcoe, Timiskaming, Kipawa, Parry Sound and Lake of Bays, encompassing a total of more than 2000 kilometres of high-resolution track line data supplemented by multibeam and sidescan sonar survey records show a consistent sub-bottom stratigraphy of relatively-thick lowermost lateglacial facies composed of interbedded semi-transparent mass flow facies (debrites, slumps) and rhythmically-laminated silty-clays. Mass flows together with cratered ('kettled') lake floors and associated deformations reflect a dynamic ice-contact glaciolacustrine environment. Exceptionally thick mass flow successions in Lake Timiskaming along the floor of the Timiskaming Graben within the seismically-active Western Quebec Seismic Zone (WQSZ), point to a higher frequency of earthquakes and slope failure during deglaciation and rapid glacio-isostatic rebound though faulting continues into the postglacial. Lateglacial faulting, diapiric deformation and slumping of coeval lateglacial sediments is observed in Parry Sound, Lake Muskoka and Lake Joseph, which are all located above prominent Precambrian terrane boundaries. Lateglacial sediments are sharply overlain by relatively-thin rhythmically-laminated and often semi

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

Science.gov (United States)

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

2015-01-01

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

Anaerobic halo- alkaliphilic bacterial community of athalassic, hypersaline Mono lake and Owens Lake in California

Science.gov (United States)

Pikuta, Elena V.; Detkova, Ekaterina N.; Bej, Asim K.; Marsic, Damien; Hoover, Richard B.

2003-02-01

The bacterial diversity of microbial extremophiles from the meromictic, hypersaline Mono Lake and a small evaporite pool in Owens Lake of California was studied. In spite of these regions had differing mineral background and different concentrations of NaCl in water they contain the same halo- alkaliphiles anaerobic bacterial community. Three new species of bacteria were detected in this community: primary anaerobe, dissipotrophic saccharolytic spirochete Spirochaeta americana strain AspG1T, primary anaerobe which is proteolytic Tindallia californiensis strain APOT, and secondary anaerobe, hydrogen using Desulfonatronum thiodismutans strain MLF1T, which is sulfate- reducer with chemo-litho-autotrophic metabolism. All of these bacteria are obligate alkaliphiles and dependent upon Na+ ions and CO32- ions in growth mediums. It is interesting that closest relationships for two of these species were isolates from samples of equatorial African soda Magadi lake: Spirochaeta americana AspG1T has 99.4% similarity on 16S rDNA- analyses with Spirochaeta alkalica Z- 7491T, and Tindallia californiensis APOT has 99.1% similarity with Tindallia magadiensis Z-7934T. But result of DNA-DNA- hybridization demonstrated less then 50% similarity between Spirochaeta americana AspG1T and Spirochaeta alkalica Z-7491T. Percent of homology between Tindallia californiensis APOT and Tindallia magadiensis Z-7934T is only 55%. The sulfate-reducer from the alkalic anaerobic community of Magadi lake Desulfonatronovibrio hydrogenovorans Z-7935T was phylogenetically distant from this sulfate-reducer in Mono lake, but genetically closer (99.7% similarity) to the sulfate-reducer, isolated from Central Asian alkalic lake Khadyn in Siberia Desulfonatronum lacustre Z-7951T. The study of key enzymes (hydrogenase and CO- hydrogenase) in Tindallia californiensis APOT and Desulfonatronum thiodismutans MLF1T showed the presence of high activity of both the enzymes in first and only hydrogenase in second

From uranium mine to fishing lake: Environmental remediation in France’s Limousin region

International Nuclear Information System (INIS)

Dixit, Aabha

2016-01-01

Artificial lakes, fishing spots and solar farms dot the landscape in France’s Limousin region, where uranium operations have gradually come to an end. This transformation would not have been possible without stakeholder involvement, transparent processes and well-coordinated activities, said Yves Marignac, the coordinator of the French Pluralistic Expert Group (GEP), involved with remediation activities in the region. The local population had an important consultative role during the environmental remediation programme, and they now use the former mining sites for recreation. “A consultative approach to remediation management is key to having the people’s support when we had to deal with the closing of the uranium mining sites in Limousin,” Marignac said. Uniquely, the non-governmental organizations (NGOs) were the driving force behind broadening the scope of environmental remediation, he added. An important factor for any successful remediation project is public engagement in the decision-making process. The local communities have the most interest in successful environmental remediation, and they need to get satisfactory answers to questions on why, when and how will it impact them. “Their involvement is vital and necessary to ensure technically sound and socially acceptable decisions,” Marignac said

From uranium mine to fishing lake: Environmental remediation in France’s Limousin region

International Nuclear Information System (INIS)

Dixit, Aabha

2016-01-01

Artificial lakes, fishing spots and solar farms dot the landscape in France’s Limousin region, where uranium operations have gradually come to an end. This transformation would not have been possible without stakeholder involvement, transparent processes and well-coordinated activities, said Yves Marignac, the coordinator of the French Pluralistic Expert Group (GEP), involved with remediation activities in the region. The local population had an important consultative role during the environmental remediation programme, and they now use the former mining sites for recreation. “A consultative approach to remediation management is key to having the people’s support when we had to deal with the closing of the uranium mining sites in Limousin,” Marignac said. Uniquely, the non-governmental organizations (NGOs) were the driving force behind broadening the scope of environmental remediation, he added. An important factor for any successful remediation project is public engagement in the decision-making process. The local communities have the most interest in successful environmental remediation, and they need to get satisfactory answers to questions on why, when and how will it impact them. “Their involvement is vital and necessary to ensure technically sound and socially acceptable decisions,” Marignac said.

Multi-Polarization ASAR Backscattering from Herbaceous Wetlands in Poyang Lake Region, China

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Huiyong Sang

2014-05-01

Full Text Available Wetlands are one of the most important ecosystems on Earth. There is an urgent need to quantify the biophysical parameters (e.g., plant height, aboveground biomass and map total remaining areas of wetlands in order to evaluate the ecological status of wetlands. In this study, Environmental Satellite/Advanced Synthetic Aperture Radar (ENVISAT/ASAR dual-polarization C-band data acquired in 2005 is tested to investigate radar backscattering mechanisms with the variation of hydrological conditions during the growing cycle of two types of herbaceous wetland species, which colonize lake borders with different elevation in Poyang Lake region, China. Phragmites communis (L. Trin. is semi-aquatic emergent vegetation with vertical stem and blade-like leaves, and the emergent Carex spp. has rhizome and long leaves. In this study, the potential of ASAR data in HH-, HV-, and VV-polarization in mapping different wetland types is examined, by observing their dynamic variations throughout the whole flooding cycle. The sensitivity of ASAR backscattering coefficients to vegetation parameters of plant height, fresh and dry biomass, and vegetation water content is also analyzed for Phragmites communis (L. Trin. and Carex spp. The research for Phragmites communis (L. Trin. shows that HH polarization is more sensitive to plant height and dry biomass than HV polarization. ASAR backscattering coefficients are relatively less sensitive to fresh biomass, especially in HV polarization. However, both are highly dependent on canopy water content. In contrast, the dependence of HH- and HV- backscattering from Carex community on vegetation parameters is poor, and the radar backscattering mechanism is controlled by ground water level.

High-frequency remote monitoring of large lakes with MODIS 500 m imagery

Science.gov (United States)

McCullough, Ian M.; Loftin, Cynthia S.; Sader, Steven A.

2012-01-01

Satellite-based remote monitoring programs of regional lake water quality largely have relied on Landsat Thematic Mapper (TM) owing to its long image archive, moderate spatial resolution (30 m), and wide sensitivity in the visible portion of the electromagnetic spectrum, despite some notable limitations such as temporal resolution (i.e., 16 days), data pre-processing requirements to improve data quality, and aging satellites. Moderate-Resolution Imaging Spectroradiometer (MODIS) sensors on Aqua/Terra platforms compensate for these shortcomings, although at the expense of spatial resolution. We developed and evaluated a remote monitoring protocol for water clarity of large lakes using MODIS 500 m data and compared MODIS utility to Landsat-based methods. MODIS images captured during May–September 2001, 2004 and 2010 were analyzed with linear regression to identify the relationship between lake water clarity and satellite-measured surface reflectance. Correlations were strong (R² = 0.72–0.94) throughout the study period; however, they were the most consistent in August, reflecting seasonally unstable lake conditions and inter-annual differences in algal productivity during the other months. The utility of MODIS data in remote water quality estimation lies in intra-annual monitoring of lake water clarity in inaccessible, large lakes, whereas Landsat is more appropriate for inter-annual, regional trend analyses of lakes ≥ 8 ha. Model accuracy is improved when ancillary variables are included to reflect seasonal lake dynamics and weather patterns that influence lake clarity. The identification of landscape-scale drivers of regional water quality is a useful way to supplement satellite-based remote monitoring programs relying on spectral data alone.

Problems with the claim of ecotype and taxon status of the wolf in the Great Lakes region

Science.gov (United States)

Cronin, Matthew A.; Mech, L. David

2009-01-01

Koblmuller et al. (2009) analysed molecular genetic data of the wolf in the Great Lakes (GL) region of the USA and concluded that the animal was a unique ecotype of grey wolf and that genetic data supported the population as a discrete wolf taxon. However, some of the literature that the researchers used to support their position actually did not, and additional confusion arises from indefinite use of terminology. Herein, we discuss the problems with designation of a wolf population as a taxon or ecotype without proper definition and assessment of criteria.

Identification of glacier motion and potentially dangerous glacial lakes in the Mt. Everest region/Nepal using spaceborne imagery

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T. Bolch

2008-12-01

Full Text Available Failures of glacial lake dams can cause outburst floods and represents a serious hazard. The potential danger of outburst floods depends on various factors like the lake's area and volume, glacier change, morphometry of the glacier and its surrounding moraines and valley, and glacier velocity. Remote sensing offers an efficient tool for displacement calculations and risk assessment of the identification of potentially dangerous glacial lakes (PDGLs and is especially helpful for remote mountainous areas. Not all important parameters can, however, be obtained using spaceborne imagery. Additional interpretation by an expert is required. ASTER data has a suitable accuracy to calculate surface velocity. Ikonos data offers more detail but requires more effort for rectification. All investigated debris-covered glacier tongues show areas with no or very slow movement rates. From 1962 to 2003 the number and area of glacial lakes increased, dominated by the occurrence and almost linear areal expansion of the moraine-dammed lakes, like the Imja Lake. Although the Imja Lake will probably still grow in the near future, the risk of an outburst flood (GLOF is considered not higher than for other glacial lakes in the area. Potentially dangerous lakes and areas of lake development are identified. There is a high probability of further lake development at Khumbu Glacier, but a low one at Lhotse Glacier.

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

Science.gov (United States)

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

2004-01-01

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

Terrestrial CDOM in Lakes of Yamal Peninsula: Connection to Lake and Lake Catchment Properties

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Yury Dvornikov

2018-01-01

Full Text Available In this study, we analyze interactions in lake and lake catchment systems of a continuous permafrost area. We assessed colored dissolved organic matter (CDOM absorption at 440 nm (a(440CDOM and absorption slope (S300–500 in lakes using field sampling and optical remote sensing data for an area of 350 km2 in Central Yamal, Siberia. Applying a CDOM algorithm (ratio of green and red band reflectance for two high spatial resolution multispectral GeoEye-1 and Worldview-2 satellite images, we were able to extrapolate the a(λCDOM data from 18 lakes sampled in the field to 356 lakes in the study area (model R2 = 0.79. Values of a(440CDOM in 356 lakes varied from 0.48 to 8.35 m−1 with a median of 1.43 m−1. This a(λCDOM dataset was used to relate lake CDOM to 17 lake and lake catchment parameters derived from optical and radar remote sensing data and from digital elevation model analysis in order to establish the parameters controlling CDOM in lakes on the Yamal Peninsula. Regression tree model and boosted regression tree analysis showed that the activity of cryogenic processes (thermocirques in the lake shores and lake water level were the two most important controls, explaining 48.4% and 28.4% of lake CDOM, respectively (R2 = 0.61. Activation of thermocirques led to a large input of terrestrial organic matter and sediments from catchments and thawed permafrost to lakes (n = 15, mean a(440CDOM = 5.3 m−1. Large lakes on the floodplain with a connection to Mordy-Yakha River received more CDOM (n = 7, mean a(440CDOM = 3.8 m−1 compared to lakes located on higher terraces.

Decline in Chinese lake phosphorus concentration accompanied by shift in sources since 2006

Science.gov (United States)

Tong, Yindong; Zhang, Wei; Wang, Xuejun; Couture, Raoul-Marie; Larssen, Thorjørn; Zhao, Yue; Li, Jing; Liang, Huijiao; Liu, Xueyan; Bu, Xiaoge; He, Wei; Zhang, Qianggong; Lin, Yan

2017-07-01

Domestic wastewater and agricultural activities are important sources of nutrient pollutants such as phosphorus and nitrogen. Upon reaching freshwater, these nutrients can lead to extensive growth of harmful algae, which results in eutrophication. Many Chinese lakes are subject to such eutrophication, especially in highly polluted areas, and as such, understanding nutrient fluxes to these lakes offers insights into the varying processes governing pollutant fluxes as well as lake water quality. Here we analyse water quality data, recorded between 2006 and 2014 in 862 freshwater lakes in four geographical regions of China, to assess the input of phosphorus from human activity. We find that improvements in sanitation of both rural and urban domestic wastewater have resulted in large-scale declines in lake phosphorus concentrations in the most populated parts of China. In more sparsely populated regions, diffuse sources such as aquaculture and livestock farming offset this decline. Anthropogenic deforestation and soil erosion may also offset decreases in point sources of pollution. In the light of these regional differences, we suggest that a spatially flexible set of policies for water quality control would be beneficial for the future health of Chinese lakes.

Housing Archetype Analysis for Home Energy-Efficient Retrofit in the Great Lakes Region

Energy Technology Data Exchange (ETDEWEB)

Kim, S. K.; Mrozowski, T.; Harrell-Seyburn, A.; Ehrlich, N.; Hembroff, L.; Bieburn, B.; Mazor, M.; McIntyre, A.; Mutton, C.; Parsons, G.; Syal, M. G.; Wilkinson, R.

2014-09-01

This project report details activities and results of the 'Market Characterization' project undertaken by the Cost Effective Energy Retrofit (CEER) team targeted toward the DOE goal of achieving 30%-50% reduction in existing building energy use. CEER consists of members from the Dow Chemical Company, Michigan State University, Ferris State University and Habitat for Humanity Kent County. The purpose of this market characterization project was to identify housing archetypes which are dominant within Great Lakes region and therefore offer significant potential for energy-efficient retrofit research and implementation due to the substantial number of homes possessing similar characteristics. Understanding the characteristics of housing groups referred to as 'archetypes' by vintage, style, and construction characteristics can allow research teams to focus their retrofit research and develop prescriptive solutions for those structure types which are prevalent and offer high potential uptake within a region or market. Key research activities included; literature review, statistical analysis of national and regional data of the American Housing Survey (AHS) collected by the U.S. Census Bureau, analysis of Michigan specific data, development of a housing taxonomy of architectural styles, case studies of two local markets (i.e., Ann Arbor and Grand Rapids in Michigan) and development of a suggested framework (or process) for characterizing local markets. In order to gain a high level perspective, national and regional data from the U.S. Census Bureau was analyzed using cross tabulations, multiple regression models, and logistic regression to characterize the housing stock and determine dominant house types using 21 variables.

Public perspectives of fire, fuels, and the Forest Service in the Great Lakes Region: a survey of citizen-agency communication and trust

Science.gov (United States)

Bruce A. Shindler; Eric Toman; Sarah M. McCaffrey

2009-01-01

Relative to the western United States, where fire and fuel management programs have received greater emphasis, few community-based studies have focused on the Great Lakes region. The present paper describes public opinion research from counties surrounding National Forests inWisconsin, Minnesota and Michigan. Survey data address citizen perspectives on (1) fuel...

Late Pleistocene to Holocene lake levels of Lake Warner, Oregon (USA) and their effect on archaeological site distribution patterns

Science.gov (United States)

Wriston, T.; Smith, G. M.

2017-12-01

Few chronological controls are available for the rise and fall of small pluvial lake systems in the Northwestern Great Basin. Within Warner Basin this control was necessary for interpretation of known archaeological sites and for predicting where evidence of its earliest inhabitants might be expected. We trenched along relic beach ridges of Lake Warner, surveyed a stratified sample of the area for archaeological sites, and excavated some sites and a nearby rockshelter. These efforts produced new ages that we used to construct a lake level curve for Lake Warner. We found that the lake filled the valley floor between ca. 30,000 cal yr BP and ca. 10,300 cal yr BP. In nearby basins, several oscillations are evident before ca. 21,100 cal yr BP, but a steep rise to the LGM maximum occurred between 21,000 and 20,000 cal yr BP. Lake Warner likely mirrored these changes, dropped to the valley floor ca. 18,340 cal yr BP, and then rose to its maximum highstand when its waters briefly reached 1454 m asl. After this highstand the lake receded to moderately high levels. Following ca. 14,385 cal yr BP, the lake oscillated between moderate to moderately-high levels through the Bolling-Allerod interstadials and into the Younger Dryas stadial. The basin's first occupants arrived along its shore around this time, while the lake still filled the valley floor. These earliest people carried either Western Stemmed or Clovis projectile points, both of which are found along the lake margin. The lake receded into the valley floor ca. 10,300 cal yr BP and dune development began, ringing wetlands and small lakes that persisted in the footprint of the once large lake. By the time Mazama tephra fell 7,600 cal yr BP it blanketed pre-existing dunes and marsh peats. Our Lake Warner lake level curve facilitates interdisciplinary testing and refinement of it and similar curves throughout the region while helping us understand the history of lake and the people who lived along its shores.

Origin and evolution of Sariñena Lake (central Ebro Basin): A piping-based model

Science.gov (United States)

Castañeda, Carmen; Javier Gracia, F.; Rodríguez-Ochoa, Rafael; Zarroca, Mario; Roqué, Carles; Linares, Rogelio; Desir, Gloria

2017-08-01

The origin and nature of the numerous lakes in the central Ebro Basin have been interpreted according to the prevailing arid or semiarid conditions, the easily-eroded materials and the solubility of the gypsum- and/or carbonate-rich Tertiary/Cenozoic substratum, involving important dissolution (karstic) and/or aeolian deflation. However, the origin of Sariñena Lake, the largest in the central Ebro Basin, remains unknown since the typical lake-generating processes in the region are not applicable. This work provides significant clues to the genesis and evolution of Sariñena Lake in a regional context. The combination of geomorphological mapping and high resolution LiDAR data together with sedimentological observations, the characterisation of soils and sediments around the lake, and the application of high-resolution geophysical techniques suggest that piping is the major genetic process driving the evolution of the Sariñena depression and lake. Field evidence demonstrates that piping is, at present, the most important erosive process in the region, generating significant collapse and surface lowering. Sariñena Lake is located within a deep endorheic depression excavated from Na-rich Tertiary materials. This work hypothesises that once an early, fluvially-originated palustrine area had developed, the progressive lowering of the regional water table linked to regional fluvial incision favoured the establishment of a hydrological gradient high enough to trigger piping processes within the claystones and siltstones underlying the original palustrine area. The Quaternary evolution of the Sariñena lacustrine basin was then controlled by successive water table fluctuations, linked to different phases of incision and alluvial deposition in the surrounding fluvial systems. All the evidence supporting a piping-related origin for this lake, together with examples of lakes generated by similar processes in different contexts, is used to propose a new genetic type of

Morphology and morphometry of upland lakes over lateritic crust, Serra dos Carajás, southeastern Amazon region.

Science.gov (United States)

Silva, Marcio S DA; Guimarães, José T F; Souza Filho, Pedro W M; Nascimento Júnior, Wilson; Sahoo, Prafulla K; Costa, Francisco R DA; Silva Júnior, Renato O; Rodrigues, Tarcísio M; Costa, Marlene F DA

2018-05-17

High-resolution satellite images, digital elevation models, bathymetric and sedimentological surveys coupled with statistical analysis were used to understand the physical environment and discuss their influence on water quality of the five upland lakes of Serra Sul dos Carajás, southeast Amazonia. The lakes have mid-altitude ranges (elevation), very small (catchment) and shallow to very shallow (central basins). Based on the length, area and volume, Violão and TI (Três Irmãs)-3 lakes may present large vertical movements of the water due to wind action and weakly stratified waters. Trophic conditions based on depth and shore development (Ld) parameters must be used with caution, since Amendoim Lake is relatively deep, but it is oligotrophic to ultra-oligotrophic. Ld values suggest that the lakes are circular to subcircular and are likely formed by solution process, as also suggested by volume development. TI-2 Lake is only presenting convex central basin and has highest dynamic ratio (DR), thus it may have high sedimentation and erosion rates. Based on the relationship between studied parameters, morphometric index and DR likely influence temperature and dissolved oxygen of waters of TI-2 Lake due to its depth profile and wind-induced surface mixing. Nevertheless, water quality parameters are controlled by catchment characteristics of the lakes.

Lake acidification in the Adirondack Mountains of New York causes and consequences

Science.gov (United States)

Carl L. Schofield

1976-01-01

Current and historic geographic distributions of acidity in Adirondack lakes were examined in relation to regional edaphic, climatic, and physiographic features. Acid conditions are currently predominant in high elevation drainage lakes having small watershed/surface area ratios. Comparable levels of acidity were found only in small seepage lakes and bog ponds during...

Remote Sensing of Lake Ice Phenology in Alaska

Science.gov (United States)

Zhang, S.; Pavelsky, T.

2017-12-01

Lake ice phenology (e.g. ice break-up and freeze-up timing) in Alaska is potentially sensitive to climate change. However, there are few current lake ice records in this region, which hinders the comprehensive understanding of interactions between climate change and lake processes. To provide a lake ice database with over a comparatively long time period (2000 - 2017) and large spatial coverage (4000+ lakes) in Alaska, we have developed an algorithm to detect the timing of lake ice using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. This approach generally consists of three major steps. First, we use a cloud mask (MOD09GA) to filter out satellite images with heavy cloud contamination. Second, daily MODIS reflectance values (MOD09GQ) of lake surface are used to extract ice pixels from water pixels. The ice status of lakes can be further identified based on the fraction of ice pixels. Third, to improve the accuracy of ice phenology detection, we execute post-processing quality control to reduce false ice events caused by outliers. We validate the proposed algorithm over six lakes by comparing with Landsat-based reference data. Validation results indicate a high correlation between the MODIS results and reference data, with normalized root mean square error (NRMSE) ranging from 1.7% to 4.6%. The time series of this lake ice product is then examined to analyze the spatial and temporal patterns of lake ice phenology.

A relative vulnerability estimation of flood disaster using data envelopment analysis in the Dongting Lake region of Hunan

Directory of Open Access Journals (Sweden)

C.-H. Li

2013-07-01

Full Text Available The vulnerability to flood disaster is addressed by a number of studies. It is of great importance to analyze the vulnerability of different regions and various periods to enable the government to make policies for distributing relief funds and help the regions to improve their capabilities against disasters, yet a recognized paradigm for such studies seems missing. Vulnerability is defined and evaluated through either physical or economic–ecological perspectives depending on the field of the researcher concerned. The vulnerability, however, is the core of both systems as it entails systematic descriptions of flood severities or disaster management units. The research mentioned often has a development perspective, and in this article we decompose the overall flood system into several factors: disaster driver, disaster environment, disaster bearer, and disaster intensity, and take the interaction mechanism among all factors as an indispensable function. The conditions of flood disaster components are demonstrated with disaster driver risk level, disaster environment stability level and disaster bearer sensitivity, respectively. The flood system vulnerability is expressed as vulnerability = f(risk, stability, sensitivity. Based on the theory, data envelopment analysis method (DEA is used to detail the relative vulnerability's spatiotemporal variation of a flood disaster system and its components in the Dongting Lake region. The study finds that although a flood disaster system's relative vulnerability is closely associated with its components' conditions, the flood system and its components have a different vulnerability level. The overall vulnerability is not the aggregation of its components' vulnerability. On a spatial scale, zones central and adjacent to Dongting Lake and/or river zones are characterized with very high vulnerability. Zones with low and very low vulnerability are mainly distributed in the periphery of the Dongting Lake region

Carbonaceous particle record in lake sediments from the Arctic and other remote areas of the northern hemisphere

International Nuclear Information System (INIS)

Rose, N.L.

1995-01-01

Lake sediments, including spheroidal carbonaceous particles produced by high temperature combustion of fossil fuels, contain a record of lake, catchment and atmospheric deposition history. The spatial and temporal distributions of these particles can indicate the extent to which a single lake or a region has been contaminated by airborne pollutants (e.g. sulfur, polycyclic aromatic hydrocarbons (PAHs)) derived from fossil fuels. The carbonaceous particle records of two Arctic lakes, Shuonijavr and Stepanovichjarvi, close to local pollution sources on the Kola Peninsula, Russia, are compared with the record of a remote lake on Svalbard and with mid-latitude remote mountain lakes in Europe and Asia. Although, Shuonijavr and Stepanovichjarvi show relatively high levels of contamination, as expected, the presence of carbonaceous particles at all of the remote sites studied suggests there is a hemispherical background of these particles. Other less remote mountain lakes in Europe have been found to contain significant concentrations of particles and these may represent regional deposition patterns. Carbonaceous particle analysis may provide an effective assessment of whether a lake site is receiving local, regional or background levels of deposition

Systematically variable planktonic carbon metabolism along a land-to-lake gradient in a Great Lakes coastal zone.

Science.gov (United States)

Weinke, Anthony D; Kendall, Scott T; Kroll, Daniel J; Strickler, Eric A; Weinert, Maggie E; Holcomb, Thomas M; Defore, Angela A; Dila, Deborah K; Snider, Michael J; Gereaux, Leon C; Biddanda, Bopaiah A

2014-11-01

During the summers of 2002-2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L -1 day -1 , respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and -33 ± 15 µg C L -1 day -1 , respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles.

THE SOMEŞAN PLATEAU LAKES: GENESIS, EVOLUTION AND TERRITORIAL REPARTITION

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Victor SOROCOVSCHI

2010-06-01

Full Text Available The present paper analyzes the genesis of the lake depressions in the Someşan Plateau and the way they evolved in time and space, as well as the morphometric elements characteristic of the different genetic types of lakes. The natural lakes in this region are few and their dimensions are small; they generally appear solitarily and only rarely as lake complexes. In this category have been included the valley lakes, the lakes formed in abandoned meanders and the lakes formed in areas with landslides. The artificial lakes are more numerous and include several genetic types. The most representative are the remnant lakes formed in the depressions resulted from the exploitation of different construction materials (kaolin sands, lime stones and the anthropic salty lakes lakes formed in abandoned salt mines from the diapir area of the Hills of Dej. The rapid evolution of these types of lakes has been highlighted through the comparative analysis of the morphometric elements obtained on the basis of topometric and bathymetric measurements. The lakes arranged for pisciculture include several subtypes (ponds, fish ponds that have been identified and characterized for the fist time, their morphometric elements being determined using digital data bases, satellite images and detailed topometric maps.

Enhanced ice sheet growth in Eurasia owing to adjacent ice-dammed lakes.

Science.gov (United States)

Krinner, G; Mangerud, J; Jakobsson, M; Crucifix, M; Ritz, C; Svendsen, J I

2004-01-29

Large proglacial lakes cool regional summer climate because of their large heat capacity, and have been shown to modify precipitation through mesoscale atmospheric feedbacks, as in the case of Lake Agassiz. Several large ice-dammed lakes, with a combined area twice that of the Caspian Sea, were formed in northern Eurasia about 90,000 years ago, during the last glacial period when an ice sheet centred over the Barents and Kara seas blocked the large northbound Russian rivers. Here we present high-resolution simulations with an atmospheric general circulation model that explicitly simulates the surface mass balance of the ice sheet. We show that the main influence of the Eurasian proglacial lakes was a significant reduction of ice sheet melting at the southern margin of the Barents-Kara ice sheet through strong regional summer cooling over large parts of Russia. In our simulations, the summer melt reduction clearly outweighs lake-induced decreases in moisture and hence snowfall, such as has been reported earlier for Lake Agassiz. We conclude that the summer cooling mechanism from proglacial lakes accelerated ice sheet growth and delayed ice sheet decay in Eurasia and probably also in North America.

Subsurface imaging reveals a confined aquifer beneath an ice-sealed Antarctic lake

DEFF Research Database (Denmark)

Dugan, H. A.; Doran, P. T.; Tulaczyk, S.

2015-01-01

Liquid water oases are rare under extreme cold desert conditions found in the Antarctic McMurdo Dry Valleys. Here we report geophysical results that indicate that Lake Vida, one of the largest lakes in the region, is nearly frozen and underlain by widespread cryoconcentrated brine. A ground...... this zone to be a confined aquifer situated in sediments with a porosity of 23-42%. Discovery of this aquifer suggests that subsurface liquid water may be more pervasive in regions of continuous permafrost than previously thought and may represent an extensive habitat for microbial populations. Key Points...... Geophysical survey finds low resistivities beneath a lake in Antarctic Dry Valleys Liquid brine abundant beneath Antarctic lake Aquifer provides microbial refugium in cold desert environment...

Climate change forces new ecological states in tropical Andean lakes.

Directory of Open Access Journals (Sweden)

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.

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (lake Caviahue, Argentina)

Science.gov (United States)

Müller, Anne; Scharf, Burkhard; von Tümpling, Wolf; Pirrung, Michael

2009-03-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout as well as from river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue Volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

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

African Journals Online (AJOL)

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.

Climate Change Adaptation Decision Making for Glacial Lake Outburst Floods From Palcacocha Lake in Peru

Science.gov (United States)

Cuellar, A. D.; McKinney, D. C.

2014-12-01

Climate change has accelerated glacial retreat in high altitude glaciated regions of Peru leading to the growth and formation of glacier lakes. Glacial lake outburst floods (GLOF) are sudden events triggered by an earthquake, avalanche into the lake or other shock that causes a sudden outflow of water. These floods are catastrophic because of their sudden onset, the difficulty predicting them, and enormous quantity of water and debris rapidly flooding downstream areas. Palcacocha Lake in the Peruvian Andes has experienced accelerated growth since it burst in 1941 and threatens the major city of Huaraz and surrounding communities. Since the 1941 flood stakeholders have advocated for projects to adapt to the increasing threat posed by Palcacocha Lake. Nonetheless, discussions surrounding projects for Palcacocha have not included a rigorous analysis of the potential consequences of a flood, probability of an event, or costs of mitigation projects. This work presents the first step to rationally analyze the risks posed by Palcacocha Lake and the various adaptation projects proposed. In this work the authors use decision analysis to asses proposed adaptation measures that would mitigate damage in downstream communities from a GLOF. We use an existing hydrodynamic model of the at-risk area to determine how adaptation projects will affect downstream flooding. Flood characteristics are used in the HEC-FIA software to estimate fatalities and injuries from an outburst flood, which we convert to monetary units using the value of a statistical life. We combine the monetary consequences of a GLOF with the cost of the proposed projects and a diffuse probability distribution for the likelihood of an event to estimate the expected cost of the adaptation plans. From this analysis we found that lowering the lake level by 15 meters has the least expected cost of any proposal despite uncertainty in the effect of lake lowering on flooding downstream.

Hydrograph Predictions of Glacial Lake Outburst Floods From an Ice-Dammed Lake

Science.gov (United States)

McCoy, S. W.; Jacquet, J.; McGrath, D.; Koschitzki, R.; Okuinghttons, J.

2017-12-01

Understanding the time evolution of glacial lake outburst floods (GLOFs), and ultimately predicting peak discharge, is crucial to mitigating the impacts of GLOFs on downstream communities and understanding concomitant surface change. The dearth of in situ measurements taken during GLOFs has left many GLOF models currently in use untested. Here we present a dataset of 13 GLOFs from Lago Cachet Dos, Aysen Region, Chile in which we detail measurements of key environmental variables (total volume drained, lake temperature, and lake inflow rate) and high temporal resolution discharge measurements at the source lake, in addition to well-constrained ice thickness and bedrock topography. Using this dataset we test two common empirical equations as well as the physically-based model of Spring-Hutter-Clarke. We find that the commonly used empirical relationships based solely on a dataset of lake volume drained fail to predict the large variability in observed peak discharges from Lago Cachet Dos. This disagreement is likely because these equations do not consider additional environmental variables that we show also control peak discharge, primarily, lake water temperature and the rate of meltwater inflow to the source lake. We find that the Spring-Hutter-Clarke model can accurately simulate the exponentially rising hydrographs that are characteristic of ice-dammed GLOFs, as well as the order of magnitude variation in peak discharge between events if the hydraulic roughness parameter is allowed to be a free fitting parameter. However, the Spring-Hutter-Clarke model over predicts peak discharge in all cases by 10 to 35%. The systematic over prediction of peak discharge by the model is related to its abrupt flood termination that misses the observed steep falling limb of the flood hydrograph. Although satisfactory model fits are produced, the range in hydraulic roughness required to obtain these fits across all events was large, which suggests that current models do not

Oh Magadi! Interpreting isoGDGTs and n-alkanes in a saline tropical lake: Lake Magadi, Kenya

Science.gov (United States)

Ferland, T. M.; Werne, J. P.; Castañeda, I. S.; Cohen, A. S.; Lowenstein, T. K.; Deocampo, D.; Renaut, R.; Bernhart, O. R.

2017-12-01

The Hominin Sites and Paleolakes Drilling Project (HSPDP) seeks to understand the paleoclimatic and paleoenvironmental context of hominin adaptation and evolution by analysis of paleolacustrine cores taken near key hominin fossil and artifact localities in Kenya and Ethiopia. We present biomarker and compound specific isotope data from a 200 m drill core from Lake Magadi, Kenya. Located 20 km from the Koora Plain in the southern Kenya Rift, and adjacent to the Olorgesailie basin, Lake Magadi is in one of the richest Early-Late Pleistocene archaeological localities in Africa, a region that has been key in debates about the relationship between climate and evolution. Present-day Lake Magadi is a saline pan, a descendant of a series of paleolakes that have occupied its drainage basin and progressively dried for approximately one million years. Nearly 70% of samples analyzed for n-alkanes recorded a robust terrestrial signal. The majority of samples did not contain the complete suite of branched GDGTs necessary to reconstruct temperature from the Methylation of Branched Tetraethers and Cyclisation of Branched Tetraethers (MBT/CBT; Weijers et al., 2007) proxy. The TetraEther indeX with 86 carbon atoms (TEX86; Schouten et al., 2002) temperature proxy was established for 90% of samples analyzed for isoGDGTs, however the Methane and Ring Indices (Zhang et al., 2011; Zhang et al., 2016) suggest that the TEX86 is not applicable to temperature reconstruction at Magadi. Despite this, the Magadi TEX86 temperature reconstruction appears to agree with not only the trends in our n-alkane data but with other regional and global records, including the GRIP-2 δ18O record. We compare our temperature data to other records in the region, and investigate influences on our TEX86 data including microbial community turnover and lake drying.

Contrasting PCB bioaccumulation patterns among Lake Huron lake trout reflect basin-specific ecology.

Science.gov (United States)

Paterson, Gordon; Ryder, Mark; Drouillard, Ken G; Haffner, G Douglas

2016-01-01

This study collected multiple age classes of lake trout from Lake Huron's Main Basin, Georgian Bay, and North Channel regions to compare and contrast top predator polychlorinated biphenyl (PCB) bioaccumulation patterns in separate compartments of the same ecosystem. Sum PCB concentrations were highest for Main Basin (260 ± 24.9 ng g(-1) wet wt) fish, followed by Georgian Bay (74.6 ± 16.2 ng g(-1) ) and North Channel (42.0 ± 3.3 ng g(-1)) fish. Discriminant functions analysis of lake trout PCB profiles and stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values clearly distinguished fish by location, indicating high degrees of basin fidelity throughout their lifetimes in addition to highly contrasting PCB bioaccumulation profiles. These unique profiles were not attributable to significant differences in lake trout lipid contents (p = 0.856) or trophic position (δ(15)N; p = 0.334), with rainbow smelt representing the primary prey across the basins. Furthermore, significant differences were observed among the basins for the relationships between PCB biomagnification factors and hydrophobicity. An empirical model for predicting PCB biomagnification in Lake Huron lake trout indicated that basin-specific population growth rates and prey abundances were significant for explaining these contrasting patterns of PCB bioaccumulation. The results of the present study are fundamental for understanding the role of ecology in legacy persistent organic pollutant (POP) bioaccumulation. Specifically, ecosystem characteristics such as prey abundances, foraging ecology, and ultimately consumer growth can regulate the variability of legacy POP bioaccumulation as observed within and among a wide range of freshwater ecosystems. © 2015 SETAC.

Modeling the GLOF Hazard Process Chain at Imja Lake in the Nepal Himalaya

Science.gov (United States)

Lala, J.; McKinney, D. C.; Rounce, D.

2017-12-01

The Hindu Kush-Himalaya region contains more glacial ice than any other non-polar region on earth. Many glacial lakes in Nepal are held in place by natural moraine dams, which are inherently unstable. Avalanches or landslides entering glacial lakes can cause tsunami-like waves that can overtop the moraines and trigger glacial lake outburst floods (GLOF). Mass loss at the Imja glacier is the highest in the Mount Everest region, and contributes to the expansion of Imja Tsho, a lake with several villages downstream. A GLOF from the lake might destroy both property and human life, making an understanding of flood triggering processes beneficial for both the downstream villages and other GLOF-prone areas globally. The process chain for an avalanche-induced GLOF was modeled numerically. The volume and velocity of debris from avalanches entering various future lake extents were calculated using RAMMS. Resulting waves and downstream flooding were simulated using BASEMENT to evaluate erosion at the terminal moraine. Wave characteristics in BASEMENT were validated with empirical equations to ensure the proper transfer of momentum from the avalanche to the lake. Moraine erosion was determined for two geomorphologic scenarios: a site-specific scenario using field samples, and a worst-case scenario based on past literature. Both cases resulted in no flooding outside the river channel at downstream villages. Worst-case scenario geomorphology resulted in increased channelization of the lake outlet and some moraine erosion but no catastrophic collapse. Site-specific data yielded similar results but with even less erosion and downstream discharge. While the models confirmed that Imja Tsho is unlikely to produce a catastrophic GLOF in the near future, they also highlight the importance of continued monitoring of the lake. Furthermore, the ease and flexibility of these methods allows for their adoption by a wide range of stakeholders for modeling other high-risk lakes.

The Legacy of Arsenic Contamination from Giant Mine, Northern Canada: An Assessment of Impacts Based on Lake Water and Lake Sediment Core Analysis

Science.gov (United States)

Blais, J. M.; Korosi, J.

2016-12-01

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

Fishing for compliments : man-made lake exceeds expectations

Energy Technology Data Exchange (ETDEWEB)

Harrison, L.

2010-10-15

This article discussed the unexpected benefits of the first man-made lake created to compensate for loss of habitat resulting from the construction of an oilsands mine. Wapan Sakahikan Lake appears to be diverting birds from a tailings pond in the vicinity, and more fish species than expected are showing up in the lake. Canadian Natural Resources Limited diverted and dammed the Tar River to make way for an oilsands mine. About 30 people were involved in the design and construction of the lake, which encompasses 80 hectares and is 19 feet deep, with shallower areas to facilitate spawning and the maturation of juvenile fish. Small islands, gravel beds, and an underwater trench for small fish to take shelter were also constructed. Special culverts help keep fish in the lake. A metre-deep layer of clay lines the lake to help prevent mercury contamination. With the aid of the spring melt, it took only three days to fill the lake. Nearby First Nations were consulted regarding the location and fish species to stock. Other oilsands companies are now creating compensation lakes, and what was learned in the creation of Wapan Sakahikan will be shared via the Regional Aquatic Monitoring Program. 1 ref., 1 fig.

Basic limnology of fifty-one lakes in Costa Rica.

Science.gov (United States)

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

2003-03-01

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

The impact of climate and environmental processes on vegetation pattern in the Czechowskie lake catchment Czechowo Region (Northern Tuchola Pinewoods) during the Younger Dryas cooling

Science.gov (United States)

Noryśkiewicz, Agnieszka Maria; Kramkowski, Mateusz; Słowiński, Michał; Zawiska, Izabela; Lutyńska, Monika; Błaszkiewicz, Mirosław; Brauer, Achim

2014-05-01

Czechowskie lake is located in the northern part of the Tuchola Pinewoods District (Northern Poland) in a young glacial landscape. At present, the majority of the area is forested or used for agricultural purposes, but among them a high amount of basins filled with biogenic sediments are present. This area is very suitable for the postglacial vegetation development investigation because of the LST ash and laminated sediments which we found in the Trzechowskie palaeolake and Czechowskie Lake (Wulf et. all 2013). The aim of the research was to reconstruct the past landscape and vegetation response to Younger Dryas cooling and we present the results of the palinological analysis done for 6 core of biogenic sediments. Our main objective was to determine whether local factors such as topography and soil cover have a significant impact on the vegetation, eutrophy and sedimentation rate at this time. In the lake Czechowskie lake catchment we have six cores that cover postglacial succession (Lake Czechowskie small basin - profile JC-12-s; Lake Czechowskiego terrace - profile TK; Lake Czechowskie vicinity - profile "Oko and Cz/80; Trzechowskie paleolake - profile T/trz; Valley between paleolake Trzechowskie and Lake Czechowskie - profile DTCZ-4). The paleoecological research carried out involved an analysis of pollen, macrofossils, Cladocera, diatom, loss-on-ignition and CaCO3 content. The results show, that the dominant plant communities during the Youngers Dryas in the region nearby Lake Czechowskie are heliophytes xeric herb vegetation with juniper (Juniperus communis) shrubs and birch (Betula) and pine (Pinus sylvestris). In the pollen diagrams there was the difference noted in the participation of the dominant pollen, the juniper pollen was always high but varied from 18 to 37%, birch average pollen share was between 17-27%. The thickness and type of the sediment accumulated in Younger Dryas in the presented profiles differs significantly. In the profiles which

Acidic pit lakes. The legacy of coal and metal surface mines

Energy Technology Data Exchange (ETDEWEB)

Geller, Walter; Schultze, Martin [Helmholtz Centre for Environmental Research - UFZ, Magdeburg (Germany); Wolkersdorfer, Christian (eds.) [Cape Breton Univ., Sydney, NS (Canada). Industrial Research Chair in Mine Water Remediation and Management; International Mine Water Association, Wendelstein (Germany). General Secretary; Kleinmann, Robert

2013-07-01

This monograph provides an international perspective on pit lakes in post-mining landscapes, including the problem of geogenic acidification. Much has been learned during the last decade through research and practical experience on how to mitigate or remediate the environmental problems of acidic pit lakes. In the first part of the book, general scientific issues are presented in 21 contributions from the fields of geo-environmental science, water chemistry, lake physics, lake modeling, and on the peculiar biological features that occur in the extreme habitats of acidic pit lakes. Another chapter provides an overview of methods currently used to remediate acidic pit lakes and treat outflowing acidic water. The second part of the book is a collection of regional surveys of pit lake problems from three European countries and Australia, and case studies of various individual representative lakes. A final case study provides an innovative approach to assessing the economic value of new pit lakes and balancing the costs and benefits, a valuable tool for decision makers.

Bathymetry of Lake Erie and Lake Saint Clair

Data.gov (United States)

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...

Mosaic maternal ancestry in the Great Lakes region of East Africa.

Science.gov (United States)

Gomes, Verónica; Pala, Maria; Salas, Antonio; Álvarez-Iglesias, Vanesa; Amorim, António; Gómez-Carballa, Alberto; Carracedo, Ángel; Clarke, Douglas J; Hill, Catherine; Mormina, Maru; Shaw, Marie-Anne; Dunne, David W; Pereira, Rui; Pereira, Vânia; Prata, Maria João; Sánchez-Diz, Paula; Rito, Teresa; Soares, Pedro; Gusmão, Leonor; Richards, Martin B

2015-09-01

The Great Lakes lie within a region of East Africa with very high human genetic diversity, home of many ethno-linguistic groups usually assumed to be the product of a small number of major dispersals. However, our knowledge of these dispersals relies primarily on the inferences of historical, linguistics and oral traditions, with attempts to match up the archaeological evidence where possible. This is an obvious area to which archaeogenetics can contribute, yet Uganda, at the heart of these developments, has not been studied for mitochondrial DNA (mtDNA) variation. Here, we compare mtDNA lineages at this putative genetic crossroads across 409 representatives of the major language groups: Bantu speakers and Eastern and Western Nilotic speakers. We show that Uganda harbours one of the highest mtDNA diversities within and between linguistic groups, with the various groups significantly differentiated from each other. Despite an inferred linguistic origin in South Sudan, the data from the two Nilotic-speaking groups point to a much more complex history, involving not only possible dispersals from Sudan and the Horn but also large-scale assimilation of autochthonous lineages within East Africa and even Uganda itself. The Eastern Nilotic group also carries signals characteristic of West-Central Africa, primarily due to Bantu influence, whereas a much stronger signal in the Western Nilotic group suggests direct West-Central African ancestry. Bantu speakers share lineages with both Nilotic groups, and also harbour East African lineages not found in Western Nilotic speakers, likely due to assimilating indigenous populations since arriving in the region ~3000 years ago.

Residence time and physical processes in lakes

Directory of Open Access Journals (Sweden)

Nicoletta SALA

2003-09-01

Full Text Available The residence time of a lake is highly dependent on internal physical processes in the water mass conditioning its hydrodynamics; early attempts to evaluate this physical parameter emphasize the complexity of the problem, which depends on very different natural phenomena with widespread synergies. The aim of this study is to analyse the agents involved in these processes and arrive at a more realistic definition of water residence time which takes account of these agents, and how they influence internal hydrodynamics. With particular reference to temperate lakes, the following characteristics are analysed: 1 the set of the lake's caloric components which, along with summer heating, determine the stabilizing effect of the surface layers, and the consequent thermal stratification, as well as the winter destabilizing effect; 2 the wind force, which transfers part of its momentum to the water mass, generating a complex of movements (turbulence, waves, currents with the production of active kinetic energy; 3 the water flowing into the lake from the tributaries, and flowing out through the outflow, from the standpoint of hydrology and of the kinetic effect generated by the introduction of these water masses into the lake. These factors were studied in the context of the general geographical properties of the lake basin and the watershed (latitude, longitude, morphology, also taking account of the local and regional climatic situation. Also analysed is the impact of ongoing climatic change on the renewal of the lake water, which is currently changing the equilibrium between lake and atmosphere, river and lake, and relationships

The endemic gastropod fauna of Lake Titicaca: correlation between molecular evolution and hydrographic history.

Science.gov (United States)

Kroll, Oliver; Hershler, Robert; Albrecht, Christian; Terrazas, Edmundo M; Apaza, Roberto; Fuentealba, Carmen; Wolff, Christian; Wilke, Thomas

2012-07-01

Lake Titicaca, situated in the Altiplano high plateau, is the only ancient lake in South America. This 2- to 3-My-old (where My is million years) water body has had a complex history that included at least five major hydrological phases during the Pleistocene. It is generally assumed that these physical events helped shape the evolutionary history of the lake's biota. Herein, we study an endemic species assemblage in Lake Titicaca, composed of members of the microgastropod genus Heleobia, to determine whether the lake has functioned as a reservoir of relic species or the site of local diversification, to evaluate congruence of the regional paleohydrology and the evolutionary history of this assemblage, and to assess whether the geographic distributions of endemic lineages are hierarchical. Our phylogenetic analyses indicate that the Titicaca/Altiplano Heleobia fauna (together with few extralimital taxa) forms a species flock. A molecular clock analysis suggests that the most recent common ancestor (MRCAs) of the Altiplano taxa evolved 0.53 (0.28-0.80) My ago and the MRCAs of the Altiplano taxa and their extralimital sister group 0.92 (0.46-1.52) My ago. The endemic species of Lake Titicaca are younger than the lake itself, implying primarily intralacustrine speciation. Moreover, the timing of evolutionary branching events and the ages of two precursors of Lake Titicaca, lakes Cabana and Ballivián, is congruent. Although Lake Titicaca appears to have been the principal site of speciation for the regional Heleobia fauna, the contemporary spatial patterns of endemism have been masked by immigration and/or emigration events of local riverine taxa, which we attribute to the unstable hydrographic history of the Altiplano. Thus, a hierarchical distribution of endemism is not evident, but instead there is a single genetic break between two regional clades. We also discuss our findings in relation to studies of other regional biota and suggest that salinity tolerance was

Best Practices for Wind Energy Development in the Great Lakes Region

Energy Technology Data Exchange (ETDEWEB)

Pebbles, Victoria; Hummer, John; Haven, Celia

2011-07-19

This report offers a menu of 18 different, yet complementary, preferred practices and policies. The best practices cover all phases of the wind energy development process - from the policies that allow for wind development, to the sustainable operation of a wind project, to the best practices for decommissioning a spent turbine - including applications for offshore wind. Each best practice describes the opportunities and challenges (pros and cons), and offers a case example that illustrates how that best practice is being utilized by a particular jurisdiction or wind project. The practices described in this publication were selected by a diverse group of interests from the Great Lakes Wind Collaborative that included environmental groups, industry, academia, and federal, state and local government regulators. The practices were identified through a year-long process that included a literature review, online survey and interviews with individuals from the public, private and non-profit sectors. Optimally, a suite of these best practices would be applied in an appropriate combination to fit the conditions of a particular wind project or a set of wind projects within a given locality or region.

75 FR 13252 - Lake Tahoe Basin Federal Advisory Committee (LTFAC)

Science.gov (United States)

2010-03-19

... Interagency Partnership on the Lake Tahoe Region and other matters raised by the Secretary. DATES: The... Act (SNPLMA) Round 11 capital projects and science themes; (2) develop a final LTFAC recommendation for the Lake Tahoe SNPLMA Round 10 capital projects and science themes, and (3) public comment. All...

Final Results From the Circumarctic Lakes Observation Network (CALON) Project

Science.gov (United States)

Hinkel, K. M.; Arp, C. D.; Eisner, W. R.; Frey, K. E.; Grosse, G.; Jones, B. M.; Kim, C.; Lenters, J. D.; Liu, H.; Townsend-Small, A.

2015-12-01

Since 2012, the physical and biogeochemical properties of ~60 lakes in northern Alaska have been investigated under CALON, a project to document landscape-scale variability of Arctic lakes in permafrost terrain. The network has ten nodes along two latitudinal transects extending inland 200 km from the Arctic Ocean. A meteorological station is deployed at each node and six representative lakes instrumented and continuously monitored, with winter and summer visits for synoptic assessment of lake conditions. Over the 4-year period, winter and summer climatology varied to create a rich range of lake responses over a short period. For example, winter 2012-13 was very cold with a thin snowpack producing thick ice across the region. Subsequent years had relatively warm winters, yet regionally variable snow resulted in differing gradients of ice thickness. Ice-out timing was unusually late in 2014 and unusually early in 2015. Lakes are typically well-mixed and largely isothermal, with minor thermal stratification occurring in deeper lakes during calm, sunny periods in summer. Lake water temperature records and morphometric data were used to estimate the ground thermal condition beneath 28 lakes. Application of a thermal equilibrium steady-state model suggests a talik penetrating the permafrost under many larger lakes, but lake geochemical data do not indicate a significant contribution of subpermafrost groundwater. Biogeochemical data reveal distinct spatial and seasonal variability in chlorophyll biomass, chromophoric dissolved organic carbon (CDOM), and major cations/anions. Generally, waters sampled beneath ice in April had distinctly higher concentrations of inorganic solutes and methane compared with August. Chlorophyll concentrations and CDOM absorption were higher in April, suggesting significant biological/biogeochemical activity under lake ice. Lakes are a positive source of methane in summer, and some also emit nitrous oxide and carbon dioxide. As part of the

An integrated approach for estimation of methane emissions from wetlands and lakes in high latitude regions

Science.gov (United States)

Chiu, C.; Bowling, L. C.; Podest, E.; Bohn, T. J.; Lettenmaier, D. P.; Schroeder, R.; McDonald, K. C.

2009-04-01

In recent years, there has been increasing evidence of significant alteration in the extent of lakes and wetlands in high latitude regions due in part to thawing permafrost, as well as other changes governing surface and subsurface hydrology. Methane is a 23 times more efficient greenhouse gas than carbon dioxide; changes in surface water extent, and the associated subsurface anaerobic conditions, are important controls on methane emissions in high latitude regions. Methane emissions from wetlands vary substantially in both time and space, and are influenced by plant growth, soil organic matter decomposition, methanogenesis, and methane oxidation controlled by soil temperature, water table level and net primary productivity (NPP). The understanding of spatial and temporal heterogeneity of surface saturation, thermal regime and carbon substrate in northern Eurasian wetlands from point measurements are limited. In order to better estimate the magnitude and variability of methane emissions from northern lakes and wetlands, we present an integrated assessment approach based on remote sensing image classification, land surface modeling and process-based ecosystem modeling. Wetlands classifications based on L-band JERS-1 SAR (100m) and ALOS PALSAR (~30m) are used together with topographic information to parameterize a lake and wetland algorithm in the Variable Infiltration Capacity (VIC) land surface model at 25 km resolution. The enhanced VIC algorithm allows subsurface moisture exchange between surface water and wetlands and includes a sub-grid parameterization of water table position within the wetland area using a generalized topographic index. Average methane emissions are simulated by using the Walter and Heimann methane emission model based on temporally and spatially varying soil temperature, net primary productivity and water table generated from the modified VIC model. Our five preliminary study areas include the Z. Dvina, Upper Volga, Yeloguy, Syum, and Chaya

Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

Science.gov (United States)

Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

2016-01-01

The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

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

Science.gov (United States)

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

2013-01-01

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

Quantifying the Variability of CH4 Emissions from Pan-Arctic Lakes with Lake Biogeochemical and Landscape Evolution Models

Science.gov (United States)

Tan, Z.; Zhuang, Q.

2014-12-01

Recent studies in the arctic and subarctic show that CH4 emissions from pan-arctic lakes are playing much more significant roles in the regional carbon cycling than previously estimated. Permafrost thawing due to pronounced warming at northern high latitudes affects lake morphology, changing its CH4 emissions. Thermokarst can enlarge the extent of artic lakes, exposing stable ancient carbon buried in the permafrost zone for degradation and changing a previously known carbon sink to a large carbon source. In some areas, the thawing of subarctic discontinuous and isolated permafrost can diminish thermokarst lakes. To date, few models have considered these important hydrological and biogeochemical processes to provide adequate estimation of CH4 emissions from these lakes. To fill this gap, we have developed a process-based climate-sensitive lake biogeochemical model and a landscape evolution model, which have been applied to quantify the state and variability of CH4 emissions from this freshwater system. Site-level experiments show the models are capable to capture the spatial and temporal variability of CH4 emissions from lakes across Siberia and Alaska. With the lake biogeochemical model solely, we estimate that the magnitude of CH4 emissions from lakes is 13.2 Tg yr-1 in the north of 60 ºN at present, which is on the same order of CH4 emissions from northern high-latitude wetlands. The maximum increment is 11.8 Tg CH4 yr-1 by the end of the 21st century when the worst warming scenario is assumed. We expect the landscape evolution model will improve the existing estimates.

Malachite green and chloramphenicol in aquatic products from regions around Dongting Lake in Hunan, China.