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249 Uppsatser om Lake sediment - Sida 12 av 17
Förbättring av den svenska kiselalgsmetoden-hantering av sedimentering
Benthic diatoms are used in Sweden for monitoring water quality in run-ning water; the method is also frequently used in other countries in Europe. One of the problems of the diatom method is the need for sedimentation of the fresh sample, to be able to decant the over standing water and add alco-hol as a preservations solution. To my knowledge, no results have been published about how long the settling time must be to ensure that the ben-thic diatoms really have settled down to avoid a loss of the diatoms when decanting the over standing water.
The aim of my investigation was to improve the Swedish method where the benthic diatoms are used for water quality monitoring. I wanted to find out the appropriate time necessary to wait until all diatoms have settled down before decanting the over standing water.
First, fresh benthic diatom samples were taken in the river Fyrisån and the lake Mälaren on different days. After arriving in the laboratory, I waited three different times (30 min, 60 and 180 min) for the diatoms to settle.
FLYTBLADSV?XTER & METANUTSL?PP - En litteraturstudie
Sedan industrialiseringen har koncentrationen metan i atmosf?ren ?kat. Metan (CH4) ?r en effektiv v?xthusgas, producerad av metanogena organismer i syrefria milj?er. K?llorna till CH4 varierar brett och ?r b?de antropogena och naturliga.
Ett landskap av tro. En uppsats om eventuella kopplingar mellan l?mningar fr?n yngre j?rn?ldern och de f?rsta kyrkornas placering i v?stra ?sterg?tland.
For some time, there has been a general thought that churches built in the Early Middle Ages in Scandinavia, around the 12th century, directly replaced cult buildings or cult sites from the Late Iron Age. There are archaeologists who have criticized this and were instead skeptical that churches at all were built on places where a pre-Christian cult building existed. Several examples from Scandinavia contradict this and show a continuity of place and cult from the Late Iron Age to the Early Middle Ages. The aim of this thesis is through a spatial analysis, study Late Iron Age archaeological sites in the landscape around thirteen churches located around lake T?kern in the western part of ?sterg?tland, to see if there is a place and cult continuity from the Late Iron Age to the Early Middle Ages at the selected locations.
Våtmarker för näringsretention i Lillån : var bör de ligga och vilken effekt kan vi förvänta
Construction of wetlands in the agricultural landscape may reduce nitrogen and phosphorus
transfer to streams, thereby reducing the eutrophication of lakes and seas. The agriculturalstream Lillån, a tributary to stream Sagån, ends up in Lake Mälaren and is transporting large amounts of these plant nutrients. The aim of this study was to estimate how hypothetical wetlands of different size and location may reduce nitrogen and phosphorus load from stream Lillån. Estimated nutrient retention in several small wetlands was compared to retention in a single large wetland based on existing data from the agricultural stream and from a nearby smaller stream. Retention in the stream was suggested to decrease along with the nutrient concentration in the water.
Märstaån ? ett vattenlandskap : Är våtmarker och dammar vägen framåt?
The overall aim is to examine how the European Union Water Framework Directive has affected the local water management in the catchment Märstaån situated in the eastern part of the lake Mälaren river basin, Sweden. The first part of the study gives an historical overview of the area with focus on how the old agricultural landscape was handling the nutrient load from farming activities by means of different kinds of wetlands. By using the concept of the procedural landscape, introduced by Torsten Hägerstrand , together with historical maps with dates starting from the 17th century, the pre-modern landscape is analyzed. The second part is an investigation, based on qualitative data, on how the different actors in the catchment area work together to secure the water quality for the Märstaån river. The analysis shows that the Märstaån catchment river systems are mostly unchanged in the rural areas. The exception is the mainstream section of the Märstaån river running partly underground today and the Halmsjöbäcken river that is heavily affected by the Arlanda airport situated within the catchment area.
Karlstad och vattnet : En studie av hur förhållningssättet till översvämningsrisk har förändrats i Karlstads kommun sedan 1950-talet
The location on the river delta of Klarälven, adjacent to lake Vänern, makes Karlstad one of the Swedish cities where a significant flood risk is present. The city has several major floods in its memory which has caused great material damage and economic losses, the latest of which occurred in the winter of year 2000/2001. The purpose of the study is to examine how the approach to flood risk has changed in the municipality of Karlstad since the 1950s, and how this change has affected the current situation regarding the city's vulnerability to flooding. To investigate this, a document analysis was conducted, where key documents in the media and from the municipality of Karlstad was studied. Furthermore, an interview study was conducted with respondents who currently are employed or previously have been employed in the municipality of Karlstad, who in various ways work with issues of flood risk. The result of the study shows that several changes have taken place since the 1950s in terms of the municipality's approach to flood risk, which for instance has led to preventative measures being taken to a greater extent than previously in the physical planning.
"Fallbacks" - betydelsen av vandringstid för Atlantlax (Salmo salar L.) som faller nedströms vandringshinder
In Lake Vänern, Sweden, there is an endemic population of Atlantic salmon (Salmo salar L.) that lives its entire life in fresh water. The salmon is hindered from migrating to its natural spawning sites in the northern part of the River Klarälven by nine hydro-electric power plants. None of the hydro-electric power plants have fishways so that salmon migrating upstream or downstream may pass. In the current situation, the upward migrating salmon are caught in a fish trap at the most downstream located power plant in Forshaga. From there, the salmon are driven in a truck, past eight power plants and released a few kilometers upstream of the eighth power plant at Edsforsen.
Konsekvensanalys för ?worst case scenario? på Mälarhamnar AB Västerås
AbstractConsequence analysis ?worst case scenario? at Mälarhamnar AB VästeråsDavid DotzskyMälarhamnar AB is a company that handle large amounts of oil, diesel, biofuel and petrol. That result in a lot of work to prevent accidents. The risks with modern technology is very small but it can?t be eliminated.
Extraterrestrisk och terrestrisk kromrik spinell i fanerozoiska kondenserade sediment
This study aims to assess the normal inflow of extraterrestrial chromite to Earth. The results from the investigationare compared to earlier studies of middle Ordovician Orthoceratite Limestone in which 1 - 3 extraterrestrial chromitegrains ( >63 ?Êm ) per kilogram limestone were found. These values have been interpreted as evidence of a twoorders of magnitude increase in the flux of extraterrestrial matter to Earth during a part of middle Ordovician.From an early Paleocene marine sedimentary sequence with known sedimentation rate in Zumaia, northernSpain, 90,5 kilogram of condensed limestone, dated to about 63 Ma, was sampled. The limestone was dissolved inhydrochloric- and hydrofluoric acid and the residue was sieved and searched for opaque minerals under the binocularmicroscope.
Fisk- och fågelpredations påverkan på den bentiska makroevertebratfaunans sammansättning under tidig vår i Tåkern
Predation is one of many factors that form the structure of the macroinvertebrate community in lakes, wetlands and watercourses. Earlier studies lack an examination concerning how fish- and waterfowl predation affect macroinvertebrates during shorter periods in the spring. I performed an exclosure study in the shallow eutrophic Lake Tåkern which is located in the western part of Östergötland County, Sweden. The experiment was performed during a three week period (1-21 April 2012) when the water temperature was low and the density of migrating diving ducks was high. The experimental cages used included three out of four different treatments; general predation (open cages), bird exclusion (net with mesh size 90*45mm) and no predation (net with mesh size 1*1mm).
I hamn : - En fallstudie av det privatoffentliga partnerskapet Vänerhamn
This study focuses upon the new societal objects that are termed public privatepartnerships where the public sector forms strategic alliances with the private sectorand the civil society to manage the wicked issues of today. An exampel of suchcooperation is Vänerhamn AB where the municipalities around the lake of Vänernand the private shipping companies got togheter to handle an economic crisis of theshipping buisiness. The partnership Vänerhamn has developed from a problematicactivity to a healthy company and the aim of this thesis is to illuminate thisdevelopment through an historical institutional approach, focusing critical junctureto discover if the governance theory can be used to understand the partnershipspositive process. This will be done through research questions about the organisation of thepartnership, about the members interests with the partnership and about eventuallycoordination problems in the partnership. The questions derive from dimensions ingovernance theory, central for the activity of partnerships. Interviews with centralinformants where held and it was complemented through a document analyses inorder to search for indications of the dimensions and that is the methodologicalapproach of the study. The conclusion of this thesis is that the governance theory can be used tounderstand Vänerhamns postive development since the members interest with thepartnership to a begining was not at all conformed and that led to obviouscoordination problems.
Biblioteksutvecklingen i Karlsborg 1907-1970 ? vägen mot ett kommunalt folkbibliotek
The purpose of this master thesis is to describe and analyse the development of the library history in the municipality of Karlsborg. This is done with a comparison to the library development in Sweden as a whole and in particular to the cities of Lidköping and Halmstad. I have worked according to the following questions: 1. How did the libraries develop before the municipality took over? 2.
Utvärdering av ett mikroalbuminuritest till hund :
The occurrence of small amounts of albumin in urine, microalbuminuria (MA), is used both in human- and veterinary medicine as an indicator for patients who have developing proteinuria. Proteinuria can be prerenal, renal or postrenal which is important to establish during an investigation. With conventional methods decreased renal function is not detected until 70 % of renal function is lost. The ability to detect and start a treatment earlier might reverse or slow the progression of disease.
The purpose of this study was to investigate the reliability of Heska® E.R.D.-Health Screen?, a test for microalbuminuria in dogs, to detect albuminuria.
Historiska emissioner av bly och arsenik till luft från Åfors Glasbruk och deras konsekvenser för miljön.
Åfors glasswork was a company which started in 1876 and closed in 2012 due to the bad economical situation in the company. After its closure, the glasswork left behind contaminated soil with different concentrations of heavy metals such as, arsenic from arsenic trioxide, a chemical used to remove bubbles during the melting of glass, and lead oxide, a chemical used in the production of crystal glass. Crystal glass?s production occurred under 1921-1971, but emissions of lead into the air from Åfors glasswork continued until 2011, because of the artist Bertil Valliens? artglas was made in Åfors glasswork from 1970?s and onwards.The aim of this study was to estimate how much lead (Pb) and arsenic (As) that were released by Åfors Glasswork into the atmosphere during the operational period of the glasswork in comparison with how much of lead and arsenic were purchased for the company. Added to the assistance of the data from National Archives the variations in the activities of Åfors glasswork could be shown.
Insect communities inhabiting Inonotus radiatus growing on Alnus glutinosa trees at northern and southern shores of boreal lakes
This is a study of the insect community associated to the wood-decaying fungus Inonotus radiatus found on Alnus glutinosa trees growing in riparian forests at the northern and southern shores of boreal lakes in the province Uppland. Little is known about this particular bracket fungus and its inhabitants. Insects were reared out at the laboratory from samples of fruiting bodies of the fungus taken at five lakes. During the fieldwork in 2009, data about several environmental variables was also taken. After the rearing period, these variables and their effects over the insects were analyzed.