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195 Uppsatser om Boreal lake - Sida 4 av 13
Näringsretention i återskapad våtmark på betesmark : studier av en mad vid Bornsjön
It is important to construct or recreate different types of wetlands and study their retention of nutrients, since knowledge of their effectiveness in this matter is poor. In 2003 a wetland was constructed on an old meadow on the western shore of Lake Bornsjön in central Sweden. The main purpose of the wetland was to reduce the amount of phosphorus entering the lake, which is the back-up water supply for Stockholm when the city cannot obtain water from Lake Mälaren. Large areas around Lake Bornsjön consist of agricultural land and the nutrient concentrations in the inflows to the lake are usually relatively high (approx. 1 mg/l total nitrogen and 0.05-0.1 mg/l total phosphorus).
Simulering av översvämningar i Byälven
Severe floods caused by heavy autumn rains in year 2000 raised the question whether measures to reduce the damage from high water levels, in the area surrounding lake Glafsfjorden and along the river Byälven down to lake Vänern, are possible. One option is to reduce flow resistance along the river and thereby lower the maximum water level a given inflow would cause. Good knowledge of hydraulic and hydrological conditions is necessary in order to estimate the effect of such flow-reducing measures. In order to quantify such effect a 1-dimensional hydraulic flow model has been set up for the river Byälven using the software package MIKE 11. The model is more detailed, especially concerning topography and bathymetry, than earlier models used for studies of the river.
Alnarps rehabiliteringsskog : ett gestalningsförslag
The understanding of the role of nature for rehabilitation of both physical and psychological
afflictions has greatly increased in the last few years. There?s a lot of science that describes
the healing effects of nature. The rehabilitation garden in Alnarp has contributed with very
positive results from the treatments of patients with burnout syndrome. In the first stages of
rehabilitation, the need for calm is very important and a demand-less and stress-free
environment is of essence.
Habitat use and ranging behaviour of GPS tracked juvenile golden eagles (Aquila chrysaetos)
Throughout its wide distribution in the northern hemisphere, the golden eagle occurs in a diverse range of environments, e.g., mountainous, forest and open areas. The literature on juvenile golden eagles is limited, and this study provides further knowledge on habitat use and ranging behaviour during the post-fledging period in boreal Sweden. A total of 14 golden eagle juveniles were tagged with GPS transmitters during 2010 and 2011, and nine could be followed during the entire post-fledging period from fledging until migration.
The juveniles fledged at the end of July and beginning of August and initiated migration during October and beginning of November. The length of the post-fledging period, until migration started, ranged from 49 to 97 days. During this period, the juveniles? distance from their natal nest and their GPS height increased with time as their flying abilities developed.
Utvärdering av Naturvårdsverkets bedömningsgrunder för makrofyter i sjöar
According to the Water Framework Directive of the European Union, macrophytes should be used as indicators in the ecological and environmental monitoring of lakes. In the member state Sweden the Environmental Protection Agency has elaborated assessment criteria for determining lake status based on macrophytes. The main focus of this thesis is to evaluate the efficiency of the assessment criteria for macrophytes. In addition the concordance between the ecological status classes of the four quality factors included was analysed.The assessment criteria for macrophytes are based on the total phosphorus preference of the respective species. The focus is thus mainly on the nutrient level of the investigated lakes and the environmental problem monitored is eutrophication.
Gröna värden i Lidingö och Lomma : inventering av upplevelsekvaliteter i grönområden som metodi kommunal planering
The aim of this study was to increase the knowledge about whooper swan (Cygnus cygnus) ecology to enhance the ability to predict and also to prevent the crop damage they cause. The largest proportion of damage in Sweden has been reported at stopover sites during spring migration in February, March and April. Therefore, this study focused on an important stopover site, Lake Tysslingen, situated in south-central Sweden. Specifically, the relation between the duration and period migrating swans stage at the stopover site and mean temperature (measured at three different weather stations) for the years 2001-2010 was studied. Furthermore, the swans´ selection for certain fields in relation to field type, distance to roosting site, a supplemental feeding site and forest edge within agricultural land surrounding the lake was analyzed.
Skärvstenshögar med människoben i norra Mälarområdet
Mounds of fire-cracked stones is a typical Bronze Age monument for the region around lake Mälaren. They are usually, because of their content, interpreted as piles of rubbish. But as they often have kerbs, are situated on cemeteries and sometimes contain human bones, the traditional interpretation is not fully satisfactory.The main focus of this essay is on the mounds of fire-cracked stones which contain human bones in the region north of lake Mälaren. With a detailed study of these, and a comparison with those without human bones, my aim is to get closer to an explanation why the human bones were deposited. The essay consist of a compilation of 98 excavated mounds and a database with various information gathered from excavation reports and archive documents.With different kinds of osteological aspects taken in consideration, the study shows that human bones have been found in about a third of the mounds.
Löslighet och metylering av kvicksilver i en förorenad sjö (Ala-Lombolo) i Kiruna kommun :
Transformation of inorganic mercury (Hg) to methyl mercury (MeHg) is a biotic process that is proposed to be conducted primarily by sulphate reducing bacteria (SRB). The formation of MeHg is of great interest because it is the mercury species that biomagnifies to the greatest extent in the aquatic food webs; about 90 % of all Hg in fish is MeHg. Our understanding of factors involved in the production of MeHg is very important for making a reliable risk assessment. The purposes of this study were to investigate the different factors that control the solubility of Hg and the production of MeHg in a contaminated lake sediment.
The lake Ala-Lombolo, Kiruna municipality, is well-known to be contaminated by mercury from different sources. Sediment cores were sampled at three different locations (N, SW and SE) in the lake and divided in three different layers; 0-5, 5-10 and 10-15 cm.
Individuell tillväxt och substratval hos en lokalt differentierad population av Asellus aquaticus
Local differentiation may occur during a short period of time and is part of the formation of new species. The isopod Asellus aquaticus is an example of a species in which local adaptation has occurred during a short period of time. An establishment of stonewort (Chara spp.) vegetation in Lake Tåkern (in the 2000) resulted in two different Asellus ecotypes; a lighter pigmented, smaller one that lives among stoneworts grazing periphytic algae, and a darker, larger ecotype that feeds on decaying leaves in reed (Phragmites australis vegetation. The purpose of this study was to examine whether there are differences in growth between ecotypes, depending on whether the food was periphytic algae or leaves, and to study the choice of substrates between the two food types. For the study, animals from both habitats were brought in from Lake Tåkern to the laboratory.
Environmental variables determining the occurrence of Cladonia parasitica and Hertelidea botryosa, two boreal lichens confined to wood
Biodiversity is essential for human well-being and it is defined as the genetic variation within species and the variety of species and ecosystems. Biodiversity provides several ecosystem services which are necessary for human beings but there are different threats towards the
biodiversity. The biodiversity linked to the forest in Sweden are threatened, about 50 % of the red-listed species in Sweden are associated with forests. This is linked to the commercial exploitation of the boreal forest in Sweden which started 200 years ago. The forestry the last
50 years, with clear-cuts, have contributed to a fragmented forest landscape.
Utbildning och ideologi-en komparativ analys av medborgerlig och politisk bildning i en svensk respektive kubansk kontext
Hunting ground graves were distinguished as a separate category during the 1930s. There is however no clear definition of what a hunting ground grave is. They have been constructed over a large area over a long period of time (200 BC-1200 AD) and their morphology varies.This paper investigates how the archaeologists have discussed the hunting ground graves since they were distinguished as a separate category until today. It investigates what concepts that have been used to define and categorize the graves as a group. It also investigates if the choices of concepts are depending on a broader societal perspective.To find the answers to these questions two surveys have been done.
Framtidens kongresshus : Stadsbyggnadsvisionen i Jönköping
Since a couple of decades the community of Jönköping has worked out an urban vision of how the city should be appropriated expanded. The prospect extends to around year 2040 and deals with the area south of lake Munksjön in Jönköping, Sweden. Today there is a proposal of how this would look like and what main public functions that should be located there. One issue in the so-called urban vision 2.0 indicates a congressional building. This report describes how such an object can be designed according to the urban vision conditions.The work is focused on three main themes;* Architectural concept and a modern form of expression.* A functional attractive congress building in a new planned town centre.* General concept of a realistic structure system that meet the spatial and architectural possibilities.Various concepts in the meeting industry and in the architecture field are identified in order to understand the concepts and ideas with today´s congress buildings.
Trädföryngring i låga gropar uppkomna vid brand i boreal naturskog :
This study was conducted in the "Kåtaberget" forest reserve in Västerbotten in the summer of 1999. In the summer of 1995, a prescribed burning was performed in the reserve. In some places where coarse dry woody debris (logs and stumps) was present, the fire consumed the wood, as well as parts of the humus layer, creating deep-burned patches. The low intensity ground fire also created dead woody debris by burning off living trees with open fire scars, as well as standing dead trees.
In this study, the post-fire tree seedling establishment was examined, with special attention given to the former presence of woody debris. The study also includes a survey of the areal extent of deep-burned patches, as well as an examination of tree seedling establishment in these patches, compared to other burnt ground.
Privat och kollektivt : Lås- och nyckelanvändning under sen järnålder i Mälardalen
The aim of this work is to give a broader and more nuanced picture of the use of locks and keys during the Iron Age, in particular the late Iron Age, in the Lake Mälaren region. This has been done by comparing two buildings: the hall on Helgö and the living quarters in the garrison on Birka. Here we can see two very different areas where locks and keys were important parts of the daily life. The study also includes a typology of padlocks based on the findings from the same places as the building study and their surroundings..
Vattensänkningar : en analys av orsaker och effekter
There are records of lowering of the water level in a lot of the Swedish lakes from the middleof the 1700th century. The aim was gaining more areable land to meet the needs of more foodto support the expanding population. In areas with top soil which contents of clay or loam asin the southwest of Scania in southern Sweden this was proven to be a successful wayexpanding the total outcome of the harvest.The studied area in the northeast of Scania, though, consists of morain with a lot of mires -much less nutritious conditions. When the water level is lowered the atmosphere gets accessto the peat. The dissolving of the organic matter that has been suppressed by the lack ofoxygene below water level continues.