A New Great Lake—Or Dead Sea?
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Geologic Site of the Month: Why Is Sebago Lake So Deep?
Why is Sebago Lake so deep? Maine Geological Survey Maine Geologic Facts and Localities February, 1999 Why is Sebago Lake so deep? 43° 51‘ 13.36“ N, 70° 33‘ 43.98“ W Text by Robert A. Johnston Maine Geological Survey, Department of Agriculture, Conservation & Forestry 1 Why is Sebago Lake so deep? Maine Geological Survey Introduction Modern geophysical equipment allows geologists to investigate previously unmapped environments, including ocean and lake floors. Recent geophysical research studied the types, composition, areal extent, and thickness of sediments on the bottom of Sebago Lake in southwestern Maine. Geologists used side- scan sonar and seismic reflection profiling to map the bottom of the lake. Approximately 58 percent of the lake bottom was imaged with side-scan sonar and over 60 miles of seismic reflection profiles were collected. This web site will discuss the findings of the seismic reflection profiling. Maine Geological Survey, Department of Agriculture, Conservation & Forestry 2 Why is Sebago Lake so deep? Maine Geological Survey Physiographic setting Sebago Lake, although second in surface area to Moosehead Lake, is Maine's deepest lake. With a water depth of 316 feet, its deepest part is 49 feet below sea level! Sebago Lake is located in southwestern Maine 20 miles northwest of Portland and 50 miles southeast of the White Mountains. It lies along the transition between the Central Highlands and the Coastal Lowlands physiographic regions of New England (Figure 1). The abrupt change in landscape can be seen in panoramic views from several vantage points near Sebago Lake. Denny, 1982 Denny, Maine Geological Survey From From Figure 1. -
Implications for Management AFRICAN GREAT LAKES
AFRICAN GREAT LAKES CONFERENCE 2nd – 5th MAY 2017, ENTEBBE, UGANDA Dynamics of Fish Stocks of Commercial Importance in Lake Victoria, East Africa: Implications for Management Robert Kayanda, Anton Taabu-Munyaho, Dismas Mbabazi, Hillary Mrosso, and Chrisphine Nyamweya INTRODUCTION • Lake Victoria with a surface area of 68,800 sqkm is the world’s second largest freshwater body • It supports one of the world’s most productive inland fisheries with the estimated total fish landings from the lake for the period of 2011 to 2014 have been about 1 million tons with a beach value increasing from about US$ 550 Million in 2011 to about US$ 840 million in 2014. • It supports about 220,000 fishers (Frame Survey 2016) • The fish stocks of Lake Victoria have changed dramatically since the introduction of Nile perch Lates niloticus during the late 1950s and early 1960s Fishery Haplochromines The Original Fish Fauna Brycinus sp Protopterus Rastrineobola Mormyrus spp Barbus spp Bagrus docmac Labeo Schilbe intermedius Oreochromis variabilis Clarias gariepinus Mormyrus spp Synodontis victoriae Oreochromis leucostictus INTRODUCTION Currently, the fisheries is dominated by four major commercial important species, these are; •Nile perch •Dagaa •Nile tilapia •Haplochromis Apart from Nile tilapia only estimated through trawl and catch surveys, the other 3 are estimated through trawl, acoustics, and catch INTRODUCTION This paper summarizes current knowledge of the status of the fish stocks and reviews the need for species specific management plans for the major commercial important fish species of Lake Victoria (Nile perch, Nile tilapia, dagaa and haplochromines). Methods • Fisheries dependent – Frame surveys – Catch assessment surveys • Fisheries independent – Acoustic – Bottom trawl Biomass and relative abundance • Total biomass from the surveys 3500 remained fairly stable over time. -
The End of the Holocene Humid Period in the Central Sahara and Thar Deserts: Societal Collapses Or New Opportunities? Andrea Zerboni1, S
60 SCIENCE HIGHLIGHTS: CLIMATE CHANGE AND CULTURAL EVOLUTION doi: 10.22498/pages.24.2.60 The end of the Holocene Humid Period in the central Sahara and Thar deserts: societal collapses or new opportunities? Andrea Zerboni1, S. biagetti2,3,4, c. Lancelotti2,3 and M. Madella2,3,5 The end of the Holocene Humid Period heavily impacted on human societies, prompting the development of new forms of social complexity and strategies for food security. Yearly climatic oscillations played a role in enhancing the resilience of past societies. The Holocene Humid Period or Holocene settlements (Haryana, India), show a general changes in settlement pattern, rather than full- climatic Optimum (ca. 12–5 ka bP), in its local, trend towards desertification and higher fledged abandonment. monsoon-tuned variants of the African Humid evapotranspiration between 5.8 and 4.2 ka bP, Period (DeMenocal et al. 2000; Gasse 2000) followed by an abrupt increase in δ18O values In the SW Fazzan, the transition from the Late and the period of strong Asian southwest (or and relative abundance of carbonates, indic- Pastoral (5-3.5 ka bP) to the Final Pastoral summer) monsoon (Dixit et al. 2014), is one ative of a sudden decrease in Indian summer (3.5-2.7 ka bP) marks the ultimate adaptation of the best-studied climatic phases of the monsoon precipitations (Dixit et al. 2014). to hyperarid conditions and, later, the rise Holocene. Yet the ensuing trend towards arid- of the Garamantian kingdom (2.7-1.5 ka bP; ity, the surface processes shaping the pres- Aridification and cultural processes Mori et al. -
Rice Lake Nature Area
Rice Lake Nature Area Location: 4120 Bassett Creek Drive Nature Area Size: 9.23 Acres Description The Rice Lake Nature Area is located along the north side of Bassett Creek Drive. The nature area is within a residential neighborhood, although the woods and wetland provide more seclusion than expected for a small urban nature area. Access to the park is through a pedestrian bridge crossing of Bassett Creek, which flows from west to east. In this reach, Bassett Creek is within an incised channel and some bank erosion is present. The creek is bordered by mixed hardwood floodplain forest and hardwood swamp. Reed canary grass is present where there is sufficient clearing, but the understory can be sparse due to heavy shading. Tree removal would likely generate a flush of reed canary grass Rice Lake Nature Area can be accessed by walking an aggregate path, and a boardwalk leading to a floating dock. South Rice Pond, sometimes referred to as Rice Lake, is a shallow basin, with a wide emergent marsh fringe. Small, shallow ponds and lakes like South Rice, are somewhat unique, as they are successionally proceeding from deeper open water to wetland. That natural process can be observed from the Rice Lake Nature Area, by observing the existing habitat and surrounding areas. The Rice Lake Nature Area provides a unique opportunity to provide an unobstructed view of South Rice Pond. Because the park is dominated by wetland, access is limited to a raised trail and boardwalk. Forest and Woodlands The southern portion of the Rice Lake Nature Area is composed of a mixture of floodplain forest and hardwood swamp. -
Water Resources Lifeblood of the Region
Water Resources Lifeblood of the Region 68 Central Asia Atlas of Natural Resources ater has long been the fundamental helped the region flourish; on the other, water, concern of Central Asia’s air, land, and biodiversity have been degraded. peoples. Few parts of the region are naturally water endowed, In this chapter, major river basins, inland seas, Wand it is unevenly distributed geographically. lakes, and reservoirs of Central Asia are presented. This scarcity has caused people to adapt in both The substantial economic and ecological benefits positive and negative ways. Vast power projects they provide are described, along with the threats and irrigation schemes have diverted most of facing them—and consequently the threats the water flow, transforming terrain, ecology, facing the economies and ecology of the country and even climate. On the one hand, powerful themselves—as a result of human activities. electrical grids and rich agricultural areas have The Amu Darya River in Karakalpakstan, Uzbekistan, with a canal (left) taking water to irrigate cotton fields.Upper right: Irrigation lifeline, Dostyk main canal in Makktaaral Rayon in South Kasakhstan Oblast, Kazakhstan. Lower right: The Charyn River in the Balkhash Lake basin, Kazakhstan. Water Resources 69 55°0'E 75°0'E 70 1:10 000 000 Central AsiaAtlas ofNaturalResources Major River Basins in Central Asia 200100 0 200 N Kilometers RUSSIAN FEDERATION 50°0'N Irty sh im 50°0'N Ish ASTANA N ura a b m Lake Zaisan E U r a KAZAKHSTAN l u s y r a S Lake Balkhash PEOPLE’S REPUBLIC Ili OF CHINA Chui Aral Sea National capital 1 International boundary S y r D a r Rivers and canals y a River basins Lake Caspian Sea BISHKEK Issyk-Kul Amu Darya UZBEKISTAN Balkhash-Alakol 40°0'N ryn KYRGYZ Na Ob-Irtysh TASHKENT REPUBLIC Syr Darya 40°0'N Ural 1 Chui-Talas AZERBAIJAN 2 Zarafshan TURKMENISTAN 2 Boundaries are not necessarily authoritative. -
Per___1. Based on the Evidence, I Believe That the Lake
Sample: Scientific Argument NAME _________________ Per___________ 1. Based on the evidence, I believe that the lake _evaporated___. I believe this due to the evidence on card B, C and D 2. On Card B it states, “In the region where the lake is found, planetary geologists have not yet observed any summer temperatures low enough to freeze methane” This is important because This evidence refutes that the lake froze. If the temperature did not get low enough to freeze, it could not have frozen. The only other option would be that the lake evaporated 2. On Card D it states, “Summer days have more hours of sunlight. Therefore, more energy is transferred to the lake in summer than any other season. This is important because If energy is transferred into the lake, this will cause the temperature of the lake to rise. If the temperature rises, there will be more kinetic energy causing the molecules to move faster. With enough energy, evaporation can occur. With more sunlight in summer, there are more hours for the energy to enter into the lake than any other season. 2. On Card C it states, “Summer started in 2002, the lake was there in 2007, there was no lake in 2009, fall started in 2010. Seasons on Titan are just over 7 years long. This is important because Titan is cold, even in the summer, because it’s so far away from the Sun. Even though it’s cold, it is a very long summer. Summer started in 2002 and the lake was there in 2007. -
The Distribution and Volume of Titan's Hydrocarbon Lakes and Seas. A. G
45th Lunar and Planetary Science Conference (2014) 2341.pdf The Distribution and Volume of Titan’s Hydrocarbon Lakes and Seas. A. G. Hayes1, R. J. Michaelides1, E. P. 2 3 4 5 2 6 1 Turtle , J. W. Barnes , J. M. Soderblom , M. Mastrogiuseppe , R. D. Lorenz , R. L. Kirk , and J. I. Lunine , 1Astronomy Department, Cornell University, Ithaca NY, [email protected]; 2Johns Hopkins Applied Physics Lab, Laurel MD; 3Physics Department, University of Idaho, Moscow ID; 4Department of Earth, Atmospheric and Planetary Sciences, MIT, Cambrige MA; 5Università La Sapienza, Italy; 6USGS Astrogeology Center, Flagstaff AZ Abstract: We present a complete map of Titan’s polar pressions [1,2]. Collectively, these features account for lacustrine features, at 1:100,000 scale, using a combi- ~1.1% of Titan’s globally observed surface area, while natio of images acquired using the RADAR, VIMS, Kraken, Ligeia, and Punga Maria account for ~80% of and ISS instruments onboard the Cassini spacecraft. all filled lake features by area. The vast majority of Synthetic Aperture Radar (SAR) images are used to filled lakes exist in the Northern hemisphere, taking up define morphologic borders while infrared images 12% of the area poleward of 55° as opposed to 0.3% in from ISS and VIMS are used to determine state of liq- the south (Figure 1). This dichotomy has been attribut- uid-fill. In addition, liquid volume estimates are de- ed to orbitally driven variations in solar insolation, rived from SAR observations using a two-layer model analogous to Earth’s Croll-Milankovich cycles [3]. calibrated by recent time-of-flight bathymetry meas- Until recently, it was unknown how many of the urements of Ligeia Mare. -
The 2019–2020 Rise in Lake Victoria Monitored from Space: Exploiting the State-Of-The-Art GRACE-FO and the Newly Released ERA-5 Reanalysis Products
sensors Article The 2019–2020 Rise in Lake Victoria Monitored from Space: Exploiting the State-of-the-Art GRACE-FO and the Newly Released ERA-5 Reanalysis Products Mehdi Khaki 1 and Joseph Awange 2,* 1 School of Engineering, University of Newcastle, Callaghan 2308, Australia; [email protected] 2 School of Earth and Planetary Sciences, Spatial Sciences, Curtin University, Perth 6102, Australia * Correspondence: [email protected] Abstract: During the period 2019–2020, Lake Victoria water levels rose at an alarming rate that has caused various problems in the region. The influence of this phenomena on surface and subsurface water resources has not yet been investigated, largely due to lack of enough in situ measurements compounded by the spatial coverage of the lake’s basin, incomplete/inconsistent hydrometeorologi- cal data, and unavailable governmental data. Within the framework of joint data assimilation into a land surface model from multi-mission satellite remote sensing, this study employs the state-of-art Gravity Recovery and Climate Experiment follow-on (GRACE-FO) time-variable terrestrial water storage (TWS), newly released ERA-5 reanalysis, and satellite radar altimetry products to understand the cause of the rise of Lake Victoria on the one hand, and the associated impacts of the rise on the total water storage compartments (surface and groundwater) triggered by the extreme climatic event on the other hand. In addition, the study investigates the impacts of large-scale ocean–atmosphere indices on the water storage changes. The results indicate a considerable increase in water storage over the past two years, with multiple subsequent positive trends mainly induced by the Indian Citation: Khaki, M.; Awange, J. -
Turkmenistan – Making the Most of Desert Resources
Turkmenistan Making the Most of Desert Resources urkmen hospitality is legendary, its roots There is little forested land. In fact, four-fifths of the in the distant past. Beyond the traditional country’s surface is desert—most of it the Karakum Khosh geldiniz (welcome), a host’s sacred (Garagum in Turkmen, the official language). And duty has always been to be hospitable to most of the remaining 20% of land is occupied Tguests, even if they are strangers. The hardship of by steep mountains. At the southwest edge of the life and travel in the desert that makes up most of Karakum, the Kopet-Dag Range rises up along the country is such that finding a friendly refuge Turkmenistan’s southern border. This range forms could be a matter of life or death. Inhospitality to a part of the Trans-Eurasian seismic belt, which is traveler is virtually unthinkable. unstable and has caused violent earthquakes in the country. An Uncompromising Terrain Turkmenistan’s most important river is the Amu Darya, the longest river in Central Asia, which Turkmenistan, the second largest Central Asian emanates from the Pamir mountains and flows country, covers 488,100 square kilometers, northwesterly through Turkmenistan. Much of its measuring about 1,100 kilometers from east to water is diverted to the west for irrigation via the west and 650 kilometers from north to south, Karakum Canal. Other major rivers are the Tejen, Upper: The Yangkala Canyon in northwestern Turkmenistan. Lower: The between the Caspian Sea in the west and the the Murgab, and the Atrek. Mausoleum of Turkmenbashi in Ahal Amu Darya River in the east. -
Turkmenistan's 'Golden Age' Lake
WL KNO EDGE NCE ISM SA ER IS E A TE N K N O K C E N N T N I S E S J E N A 3 V H A A N H Z И O E P W O I T E D N E Z I A M I C O N O C C I O T N S H O E L C A I N M Z E N O T Turkmenistan’s ‘Golden Age’ Lake: a Potential Environmental Disaster Zhulduz Baizakova Republic of Kazakhstan Open Source, Foreign Perspective, Underconsidered/Understudied Topics The Foreign Military Studies Office (FMSO) at Fort Leavenworth, Kansas, is an open source research organization of the U.S. Army. It was founded in 1986 as an innovative program that brought together military specialists and civilian academics to focus on military and security topics derived from unclassified, foreign media. Today FMSO maintains this research tradition of special insight and highly collaborative work by conducting unclassified research on foreign perspectives of defense and security issues that are understudied or unconsidered. Author Background Zhulduz Baizakova is a graduate of the Kazakh National University and has a MSc degree in International Security and Global Governance, Birkbeck College, University of London, where she successfully defended her dissertation on NATO peacekeeping activities. She served for seven years in the Ministry for Foreign Affairs of the Republic of Kazakhstan, including a posting to the United Kingdom. Baizakova is currently specializing in defense and security issues in Central Asia. FMSO has provided some editing, format, and graphics to this paper to conform to organizational standards. -
Madison Lake (07-0044) Blue Earth County, Minnesota
Sentinel Lake Assessment Report Madison Lake (07-0044) Blue Earth County, Minnesota Minnesota Pollution Control Agency Water Monitoring Section Lakes and Streams Monitoring Unit & Minnesota Department of Natural Resources Section of Fisheries August 2010 Minnesota Pollution Control Agency 520 Lafayette Road North Saint Paul, MN 55155-4194 http://www.pca.state.mn.us 651-296-6300 or 800-657-3864 toll free TTY 651-282-5332 or 800-657-3864 toll free Available in alternative formats Contributing Authors Matt Lindon MPCA Ray Valley and Scott Mackenthun MDNR Editing Steve Heiskary & Dana Vanderbosch, MPCA Peter Jacobson, MDNR Sampling Matt Lindon, MPCA Jacquelyn Bacigalupi, Marc Bacigalupi, Marcus Beck, Craig Berberich, Nathan Burkhart, Tyler Fellows, Corey Geving, John Hoxmeier, Seth Luchau, Jason Rhoten, Kim Strand, Ray Valley, MDNR Patrice Johnson, Susie Jedlund, Master Naturalist Program Curt Kloss, Citizen Lake Monitoring Program Volunteer Mary Buschkowsky and Frank McCabe, Volunteer Ice out data wq-2slice07-0044 The MPCA is reducing printing and mailing costs by using the Internet to distribute reports and information to wider audience. For additional information, see the Web site: www.pca.state.mn.us/water/lakereport.html This report was printed on recycled paper manufactured without the use of elemental chlorine (cover: 100% post-consumer; body: 100% post-consumer) 2009 Sentinel Lake Assessment of Minnesota Pollution Control Agency and Madison Lake in Blue Earth County Minnesota Department of Natural Resources i Table of Contents List -
The Lakes and Seas of Titan • Explore Related Articles • Search Keywords Alexander G
EA44CH04-Hayes ARI 17 May 2016 14:59 ANNUAL REVIEWS Further Click here to view this article's online features: • Download figures as PPT slides • Navigate linked references • Download citations The Lakes and Seas of Titan • Explore related articles • Search keywords Alexander G. Hayes Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, New York 14853; email: [email protected] Annu. Rev. Earth Planet. Sci. 2016. 44:57–83 Keywords First published online as a Review in Advance on Cassini, Saturn, icy satellites, hydrology, hydrocarbons, climate April 27, 2016 The Annual Review of Earth and Planetary Sciences is Abstract online at earth.annualreviews.org Analogous to Earth’s water cycle, Titan’s methane-based hydrologic cycle This article’s doi: supports standing bodies of liquid and drives processes that result in common 10.1146/annurev-earth-060115-012247 Annu. Rev. Earth Planet. Sci. 2016.44:57-83. Downloaded from annualreviews.org morphologic features including dunes, channels, lakes, and seas. Like lakes Access provided by University of Chicago Libraries on 03/07/17. For personal use only. Copyright c 2016 by Annual Reviews. on Earth and early Mars, Titan’s lakes and seas preserve a record of its All rights reserved climate and surface evolution. Unlike on Earth, the volume of liquid exposed on Titan’s surface is only a small fraction of the atmospheric reservoir. The volume and bulk composition of the seas can constrain the age and nature of atmospheric methane, as well as its interaction with surface reservoirs. Similarly, the morphology of lacustrine basins chronicles the history of the polar landscape over multiple temporal and spatial scales.