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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Protection of the Environment of the Baltic Sea under the 1992 Helsinki Convention and the Law of European Community / Baltijos jūros aplinkos apsauga pagal 1992 m. Helsinkio konvenciją ir Europos Bendrijos teisę

Klumbytė, Skirmantė 23 January 2008 (has links)
Summary of dissertation explains the object and tasks of the research, outlines its sources and methods, reveals academic novelty and practical importance of the study, lists the main theses of the dissertation and elaborates on the conclusions and proposals. / Disertacijos santraukoje nurodomas tyrimo objektas, tikslas ir uždaviniai, apžvelgiami tyrimo šaltiniai, atskleidžiamas darbo mokslinis naujumas ir praktinė reikšmė, nurodomi pagrindiniai disertacijos teiginiai, pateikiamos išvados ir pasiūlymai.
82

Study of the south-eastern Baltic Sea development applying geological modeling methods / Pietrytinės Baltijos jūros raidos analizė taikant geologinio modeliavimo metodus

Šečkus, Jonas 07 July 2009 (has links)
The main subject of the present research is the geological development of the south-eastern Baltic Sea in Holocene (11000 – 0 calendar years before the present) and prediction of its development in the future (0-1000 calendar years after the present). The present is calendar years 2000AD. The working area is estimated between longitude 18ºE - 21º30’E and latitude between 54ºN - 56º30’N including the onshore and offshore of Lithuania. The quantitative and qualitative geological information and the geological interpretation allowed the 4D modeling of the south-eastern Baltic Sea. Detailed comparison of the influence of isostatic and eustatic components has made it possible to distinguish between these two factors and to create the isostatic intensity models. Last investigations of the global sea level rise (IPCC 2001, 2007) and the model of the recent tectonic activity in the region were used for creation of the prognosis scenarios of relief development in the future. The 4D models created in this dissertation are very well understandable for specialists and for wider readership not engaged in scientific research. The results presented in the dissertation can be useful also by archaeologists and biologists. The results of the model show all the drawbacks of geological material collected so far and outline new perspectives for marine geologists, i.e. demonstrate what works should be done in the future to get more precise results. / Pagrindinis tyrimų tikslas buvo atkurti pietrytinės Baltijos jūros raidą holocene (11000 – 0 kalendorinių metų iki dabar) ir atlikti jūros raidos prognozę iki 1000 metų nuo dabar. Tirtasis regionas apima Lietuvos teritoriją (tiek atviroje jūroje, tiek sausumoje), jo koordinatės yra 18ºE - 21º30’E rytų ilgumos ir 54ºN - 56º30‘N šiaurės platumos. Kokybinė ir kiekybinė geologinė informacija bei jos geologinė interpretacija leido sukurti pietrytinės Baltijos jūros raidos 4D modelius. Detalus kiekybinis eustatinių bei izostatinių vandens lygio pokyčių palyginimas leido atskirti šiuos faktorius bei nustatyti izostatinio komponento intensyvumą holoceno metu. Kiekybiškai įvertinus tektoninius judesius ir vandens lygio pokyčius buvo atlikta pietrytinės Baltijos jūros raidos prognozė. Erdviniai 4 D modeliai pateikti šiame darbe yra lengvai suprantami ne tik specialistams, tačiau ir plačiai visuomenei. Disertacijoje pateikti modeliai gali būti naudingi archeologams bei biologams, tuo pačiu geologams parodydami esančių duomenų trūkumus bei nubrėžiantys naujas perspektyvas tyrimams, kurie turėtų būti atlikti norint gauti kiek galima detalesnius rezultatus.
83

Study of the south-eastern Baltic Sea development applying geological modeling methods / Pietrytinės Baltijos jūros raidos analizė taikant geologinio modeliavimo metodus

Šečkus, Jonas 07 July 2009 (has links)
The main subject of the present research is the geological development of the south-eastern Baltic Sea in Holocene (11000 – 0 calendar years before the present) and prediction of its development in the future (0-1000 calendar years after the present). The present is calendar years 2000AD. The working area is estimated between longitude 18ºE - 21º30’E and latitude between 54ºN - 56º30’N including the onshore and offshore of Lithuania. The quantitative and qualitative geological information and the geological interpretation allowed the 4D modeling of the south-eastern Baltic Sea. Detailed comparison of the influence of isostatic and eustatic components has made it possible to distinguish between these two factors and to create the isostatic intensity models. Last investigations of the global sea level rise (IPCC 2001, 2007) and the model of the recent tectonic activity in the region were used for creation of the prognosis scenarios of relief development in the future. The 4D models created in this dissertation are very well understandable for specialists and for wider readership not engaged in scientific research. The results presented in the dissertation can be useful also by archaeologists and biologists. The results of the model show all the drawbacks of geological material collected so far and outline new perspectives for marine geologists, i.e. demonstrate what works should be done in the future to get more precise results. / Pagrindinis tyrimų tikslas buvo atkurti pietrytinės Baltijos jūros raidą holocene (11000 – 0 kalendorinių metų iki dabar) ir atlikti jūros raidos prognozę iki 1000 metų nuo dabar. Tirtasis regionas apima Lietuvos teritoriją (tiek atviroje jūroje, tiek sausumoje), jo koordinatės yra 18ºE - 21º30’E rytų ilgumos ir 54ºN - 56º30‘N šiaurės platumos. Kokybinė ir kiekybinė geologinė informacija bei jos geologinė interpretacija leido sukurti pietrytinės Baltijos jūros raidos 4D modelius. Detalus kiekybinis eustatinių bei izostatinių vandens lygio pokyčių palyginimas leido atskirti šiuos faktorius bei nustatyti izostatinio komponento intensyvumą holoceno metu. Kiekybiškai įvertinus tektoninius judesius ir vandens lygio pokyčius buvo atlikta pietrytinės Baltijos jūros raidos prognozė. Erdviniai 4 D modeliai pateikti šiame darbe yra lengvai suprantami ne tik specialistams, tačiau ir plačiai visuomenei. Disertacijoje pateikti modeliai gali būti naudingi archeologams bei biologams, tuo pačiu geologams parodydami esančių duomenų trūkumus bei nubrėžiantys naujas perspektyvas tyrimams, kurie turėtų būti atlikti norint gauti kiek galima detalesnius rezultatus.
84

Pirmininkavimas Europos Sąjungai ir Baltijos jūros valstybių regioninis bendradarbiavimas / Presidency of the Council of the European Union (EU) and regional cooperation of Baltic Sea states

Karaliūtė, Greta 07 June 2012 (has links)
Pirmininkavimas Europos Sąjungos (ES) Tarybai yra vienas iš būdų įgyvendinti bendrą ES politiką, bet valstybės narės siekia pasinaudoti šia pareigybe sprendžiant savo šaliai ar regionui aktualius klausimus. Besiplėtojantys ekonominiai, politiniai ir kultūriniai ryšiai Baltijos jūros regione gali atskleisti bendrus kaimyninių valstybių prioritetus formuojant ES Tarybos darbotvarkę. Šiame tyrime Baltijos jūros regionu laikomos Danija, Švedija, Suomija ir Lietuva. Šiaurės valstybės (Suomija, Švedija, Danija) ir Lietuva turi gana skirtingus socialinio ir ekonominio vystymosi modelius, todėl tai gali reikšti, jog jų regioniniai ryšiai gali būti ne tokie stiprūs kaip ryšiai su kitomis ES valstybėmis. Tai gali turėti įtakos valstybių laikysenai pirmininkaujant ES Tarybai. Šiame tyrime siekiama patvirtinti arba paneigti hipotezę, kad Baltijos jūros regiono valstybės pirmininkaudamos ES Tarybai sureikšmina vienus ir tuos pačius regionui svarbius klausimus. Tiriami Baltijos regiono valstybių paskutiniai pirmininkavimai (Suomijos 2006 m., Švedijos 2009 m., Danija pirmininkauja šiuo metu, 2012 m., o Lietuva pirmininkaus 2013 m. antrojoje pusėje). Pasirinktos energetikos, aplinkosaugos ir susisiekimo, sritys, kaip pagrindinės probleminės sferos skatinančios regioninį bendradarbiavimą. Remiantis šiomis politikos sritimis siekiama išsiaiškinti pirmininkavimo prioritetų ir regionalizmo ryšį bei išanalizuoti valstybių keliamų prioritetų bendrumus ir skirtumus. / The Presidency of the Council of the EU can be conceived as the one of tools implementing common policy of the EU. Member states try to profit this position meeting the issues relevant for their own country or region. Evolving economic, political and cultural relations in the Baltic Sea region may reveal a number of priorities of neighboring countries in shaping the agenda of the Council of the EU. In this research the Baltic Sea region means Denmark, Sweden, Finland and Lithuania. Nordic countries (Finland, Sweden, Denmark) and Lithuania have quite different social and economic development models, and this may cause that their regional ties may not be as strong as the relationship with other EU countries. This can affect the attitude of the country in presidency of the EU. This investigation aims to confirm or refute the hypothesis that the Baltic Sea region states chairing the EU Council at the central room put the same and one of the most important regional issues. It is analyzing the most recent presidencies of the Baltic Sea region states (Finland in 2006, Sweden in 2009, Denmark is chairing currently, 2012, and Lithuania will hold presidency in the second half of 2013). Particular policy areas are chosen, precisely energy, environment and transport, as the main problems leading to regional cooperation. Based on these policies the aim is to find the link between the presidency priorities and regionalism and to describe the commonalities and differences of it.
85

Fate of perfluoroalkyl acids in the aquatic environment with a focus on mass balance studies

Filipovic, Marko January 2015 (has links)
Perfluoroalkyl substances (PFASs) are man-made chemicals. Their unique properties make them beneficial for a wide range of industrial and consumer product applications, such as in aqueous film forming foam (AFFF), durable water repellent clothing, hydraulic oils and food packaging materials. Perfluoroalkyl acids (PFAAs), a class of PFASs, are highly persistent in the environment, and long chain PFAAs are bioaccumulative and toxic. International regulation and voluntary actions by the industry have been implemented and led to a recent reduction of primary emissions of PFAAs to the environment. However, point sources such as AFFF training sites as well as diffuse sources continue to contaminate water bodies, soil and biota. Reducing environmental pollution with PFAAs has therefore become a regulatory priority. Designing successful measures to reduce the PFAA contamination requires an understanding of the sources, transport and fate of PFAAs in the environment. Four scientific publications are included in this PhD thesis, which aimed at increasing the holistic understanding of the fate of PFAAs in aquatic systems. This was achieved by chemical trace analysis combined with mass balance modeling. The following topics were covered: Dispersion and fate of PFAAs from an AFFF-impacted site (Paper I), recirculation of PFAAs in the aquatic environment with focus on waste water treatment plants (WWTPs, Paper II), mass balance of PFAAs in the Baltic Sea (Paper III) and transport and fate of PFAAs in two pristine boreal stream catchments (Paper IV). Results from Paper I showed that AFFF-impacted sites at a former military airfield, which was abandoned for more than 30 years, continue to be point sources of PFAAs to recipients. The sum of PFAAs in the ground water and surface waters ranged from 740 to 51000 ng L-1 and &lt;0.5 to 79 ng L-1, respectively. PFOS in muscle tissue of European perch from a nearby lake ranged from 77 to 370 ng g-1 wet weight, representing among the highest values reported worldwide for fish muscle. In Paper II the relative importance of environmental recirculation of PFAAs versus new releases from the technosphere was investigated for PFAAs in WWTP influents. It was shown that tap water can be an important source of PFAAs to WWTPs in areas with elevated environmental levels. This needs to be taken into account when calculating emissions via WWTP effluents. PFAA mass balances over the WWTPs suggested that PFHxA and PFOA were formed from precursor compounds within the plants. Assembled PFAA mass balances for the Baltic Sea (Paper III) showed that river inflow and atmospheric deposition were the dominant input pathways, while wastewater treatment plant (WWTP) effluents discharging directly into the Baltic Sea made a minor contribution. The inputs of PFAAs were estimated to be higher than the outputs, suggesting a current increase of the PFAA inventory in the Baltic Sea. Also the mass balance study of PFAAs in two remote stream catchments presented in Paper IV revealed that inputs dominated over outputs for both catchments, indicating that a considerable portion of the PFAAs deposited from the atmosphere is retained in soil or in deep ground water and may be released to surface and marine water environments in the future / Perfluoralkilne tvari (PFASs) su umjetne kemikalije. Zbog svojih jedinstvenih svojstava široko su primjenjive u industriji i izradi proizvoda krajnje potrošnje kao što su pjena za gašenje požara (AFFF), vodootporna odjeća, hidraulična ulja i pakiranja za hranu. Perfluoralkilna kiselina (PFAAs) iz skupine perfluoralkilnih tvari iznimno je dugotrajna u okolišu, a dugolančane PFAAs su bioakumulativne i otrovne. Poduzeta međunarodna regulativa i dobrovoljne akcije vodile su nedavno smanjenoj primarnoj emisiji PFAAs u okoliš. Unatoč tome, primarni izvori, kao što su mjesta na kojima se provode treninzi za gašenje požara i difuzni izvori i dalje zagađuju vode, tlo i biotu. Zbog toga, smanjenje onečišćenja okoliša izazvanog PFAAs predstavlja regulatorni prioritet. Stvaranje uspješnih mjera kojima bi se smanjilo onečišćenje izazvano PFAAs zahtjeva razumijevanje izvora, prijenosa i sudbine tih tvari u okolišu. U ovaj doktorat uključena su četiri znanstvena članka kojima je cilj povećati sveukupno razumijevanje sudbine PFAAs u vodenim sustavima. To je postignuto kemijskom analizom elemenata u tragovima u kombinaciji s modeliranjem masene ravnoteže. Obrađene su sljedeće teme: Širenje i sudbina PFAAs na područjima zahvaćenim AFFF (Članak I), ponovna cirkulacija PFAAs u vodenom okolišu s naglaskom na postrojenja za pročišćavanje otpadnih voda (Članak II), masena ravnoteža PFAAs u Baltičkom moru (Članak III) te prijenos i sudbina PFAAs u dva udaljena sjeverna vodena toka (Članak IV).   Rezultati iz Članka I pokazali su da su područja zahvaćena AFFF na bivšem vojnom aerodromu napuštenom prije 30 godina i dalje je glavni izvor PFAA zagadenja okolisa. Zbroj PFAAs u podzemnim i površinskim vodama kreće se u rasponu od 740 do 51000 ng L-1 i &lt;0.5 do 79 ng L-1. PFOS u mišićnom tkivu grgeča iz obližnjeg jezera kreće se od 77 do 370 ng g-1 mokre težine, predstavljajući jednu od najviših vrijednosti u svijetu za riblje mišiće. Članak II istražuje relativnu važnost ponovne cirkulacije PFAAs imajući na umu novu emisiju PFAAs iz tehnosfere u postrojenjima za pročišćavanje otpadnih voda. Cirkulacija/kruženje u okolišu može se pojaviti kada PFAAs iz sustava pitke voda (rijeka, bunara i jezera) odlaze u otpadne vode. Prikazano je kako voda iz slavine može biti važan izvor PFAAs sustavima za pročišćavanje otpadnih voda u područjima s povišenim razinama zaštite okoliša. To se treba uzeti u obzir pri računanju emisije putem strojeva koji se koriste za pročišćenje otpadnih voda. Masena ravnoteža PFAA u postrojenjima za pročišćavanje otpadnih voda upućuje na to da su PFHxA i PFOA stvoreni kao prethodni spojevi unutar postrojenja. Prikupljene masene ravnoteže PFAA za Baltičko more (Članak III) pokazale su da su pritoke rijeka i atmosfersko taloženje dominantni ulazni putovi, dok postrojenja za pročišćenje otpadnih voda pridonose tek u manjoj mjeri. Ulaz PFAAs je procijenjen višim od izlaza, što objašnjava trenutno povećanje sadržaja PFAA u Baltičkom moru. Masena ravnoteža PFAAs u dva udaljena riječna toka predstavljena u Članku IV otkriva da ulaz dominira nad izlazom za oba riječna toka, što upućuje na značajan udio PFAAs koji je iz atmosfere zadržan u tlu ili podzemnim vodama te može biti ispušten u područja površinskih voda i mora. / Perfluorerade alkylsyror (PFAA) är kemikalier som är producerade av människan. Deras unika egenskaper gör att de kan användas i många olika industriella applikationer. PFAAs används i brandsläckningsskum, vattenavvisande kläder, hydrauliska oljor och matförpackningar. PFAAs har visat sig vara persistenta i miljön, och långkedjiga PFAA-homologer har visat sig vara bioackumulerbara samt ha en toxisk verkan. Reglering på internationell nivå tillsammans med initiativ från industrin har lett till minskning av direkta utsläpp. Punktkällor som brandövningsplatser samt andra diffusa källor fortsätter att förorena omgivande vattendrag, jordlager och fauna. Den utbredda föroreningen av PFAAs har därför blivit prioriterad för reglering. För att förstå utsläppen av PFAAs i miljön, hur de transporteras samt deras öde i miljön, är det viktigt att utföra studier som belyser dessa områden.   Denna doktorsavhandling inkluderar fyra vetenskapliga publikationer. Syftet med de underliggande studierna var att öka den holistiska förståelsen av PFAAs rörelse i akvatiska system. Studierna gjordes genom att kombinera kemiska analysmetoder med modellering. Följande  studier genomfördes; Transport och spridning av PFAAs från en brandövningsplats (Paper I), recyklering av PFAAs i den akvatiska miljön med fokus på vattenreningsverk (Paper II), massbalans av PFAAs i Östersjön (Paper III), transport och öde av PFAAs i två pristina vattendrag (Paper IV).   Resultat från (Paper I) visade att brandövningsplatser vid en flygplats som inte har varit i bruk i mer än 30 år, fortfarande är punktkällor av PFAAs till omgivande vattendrag. Summan av PFAAs koncentrationer i grundvattnet och ytvattnet sträckte sig från 740 till 51000 ng L-1 och &lt;0.5 till 79 ng L-1 i respektive vattendrag. Koncentrationen av PFOS i muskelvävnad från  aborre i en av sjöarna var 77 till 370 ng g-1 våtvikt. Dessa värden representerar några av de högsta uppmätta koncentrationerna i världen. I Paper II testades betydelsen av PFAAs från recirkulering i miljön i jämförelse med nya utsläpp från teknosfären. Recirkulering av PFAAs i miljön kan förekomma då PFAAs i inkommande vatten till reningsverk kommer från dricksvatten. Denna studie visar att dricksvatten kan vara en påtaglig källa av PFAAs till vattenreningsverk i områden med förhöjda halter av PFAAs i miljön. Detta måste tas hänsyn till när man beräknar emissioner med utgående vatten från vattenreningsverk. Massbalanser av PFAAs i reningsverken visar att PFHxA och PFOA bildades av prekursorämnen i vattenreningsverken. I Paper III beräknades massbalanserna av PFAAs i Östersjön, beräkningarna visar att floder och atmosfärisk nedebörd var de viktigaste källorna medan utsläppen från vattenreningsverk var markant lägre. Importen av PFAAs estimerades vara högre än exporten, varför vi tror att PFAAs mängden I Östersjön kommer att öka över tid. Vidare gjordes en mass balans av PFAAs i två avlägsna avrinningsområden (Paper IV). Resultaten visar att importen av PFAAs dominerar över exporten från båda avrinningsområdena. Detta indikerar att en stor del av PFAAs som kommer ner via nederbörd kommer att ansamlas i jorden eller i grundvattnet. Dessa PFAAs kan vid senare tillfälle komma att släppas ut till floder som rinner ut i marina vatten. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p><p> </p>
86

Control factors of the marine nitrogen cycle : The role of meiofauna, macrofauna, oxygen and aggregates

Bonaglia, Stefano January 2015 (has links)
The ocean is the most extended biome present on our planet. Recent decades have seen a dramatic increase in the number and gravity of threats impacting the ocean, including discharge of pollutants, cultural eutrophication and spread of alien species. It is essential therefore to understand how different impacts may affect the marine realm, its life forms and biogeochemical cycles. The marine nitrogen cycle is of particular importance because nitrogen is the limiting factor in the ocean and a better understanding of its reaction mechanisms and regulation is indispensable. Furthermore, new nitrogen pathways have continuously been described. The scope of this project was to better constrain cause-effect mechanisms of microbially mediated nitrogen pathways, and how these can be affected by biotic and abiotic factors. This thesis demonstrates that meiofauna, the most abundant animal group inhabiting the world’s seafloors, considerably alters nitrogen cycling by enhancing nitrogen loss from the system. In contrast, larger fauna such as the polychaete Marenzelleria spp. enhance nitrogen retention, when they invade eutrophic Baltic Sea sediments. Sediment anoxia, caused by nutrient excess, has negative consequences for ecosystem processes such as nitrogen removal because it stops nitrification, which in turn limits both denitrification and anammox. This was the case of Himmerfjärden and Byfjord, two estuarine systems affected by anthropogenic activities, such as treated sewage discharges. When Byfjord was artificially oxygenated, nitrate reduction mechanisms started just one month after pumping. However, the balance between denitrification and nitrate ammonification did not favor either nitrogen removal or its retention. Anoxia is also present in aggregates of the filamentous cyanobacteria Nodularia spumigena. This thesis shows that even in fully oxic waters, millimetric aggregates can host anaerobic nitrogen processes, with clear implications for the pelagic compartment. While the thesis contributed to our knowledge on marine nitrogen cycling, more data need to be collected and experiments performed in order to understand key processes and regulation mechanisms of element cycles in the ocean. In this way, stakeholders may follow and take decisions in order to limit the continuous flow of human metabolites and impacts on the marine environment. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p>
87

Effects of light and carbon on phytoplankton production and phyto-microzooplankton trophic interactions in the Baltic Sea: a mesocosm experiment

Rahman, Mohammad Habibur January 2015 (has links)
A mesocosm experiment with four triplicated treatments (control, clear carbon, pigment and dissolved organic matter) was carried out to investigate the effects of light (by pigment addition) and carbon (C) on phytoplankton communities and on the grazing pressure of microzooplankton on phytoplankton in the Baltic Sea. Phytoplankton concentration and species composition were determined by using an inverted microscope following the Utermöhl method. In order to measure differences in phyto-zooplankton trophic interactions between treatments, a dilution experiment was performed at the end of the mesocosm experiment. Surprisingly, the results show that light attenuation was beneficial to phytoplankton production while carbon enrichment had negative effects on phytoplankton production, the highest phytoplankton production was in the low light treatment and lowest phytoplankton production was in the clear C treatment. Cyanobacteria were the most dominant group, representing over 95% of the phytoplankton community. Diatoms were the least dominant group, representing less than 5% of the phytoplankton community. Microzooplankton grazing pressure was affected by light attenuation and C enrichment. Grazing pressure was highest on cyanobacteria in the clear C treatment, but chrysophytes experienced low grazing pressure and had high growth rates in the Control treatment where microzooplankton fed selectively on chrysophytes. The least abundant group, diatoms, decreased although they experienced no grazing pressure in the Control and clear C treatments. This experiment resulted in two surprising findings. First, increased light intensity reduced phytoplankton biomass, especially in the clear C treatment, and second, cyanobacteria constituted an important food source for microzooplankton grazers. This study adds to the increasing evidence that light effects can be counterintuitive and that cyanobacteria are not necessarily grazing resistant and can meditate nutrient transport to higher trophic levels.
88

Ecology of juvenile turbot and flounder in the Central Baltic Sea : Implications for recruitment

Martinsson, Jesper January 2011 (has links)
Our understanding of turbot and flounder ecology in the Baltic Sea is insufficient for sound management decisions. This thesis aims to fill some gaps in current knowledge by providing information of the ecology of turbot and flounder within their juvenile habitat, and to relate these findings to issues assumed relevant for recruitment variation. Main focus is on turbot due to its relatively low abundance and high variability in recruitment. The distribution of both species was studied on different scales, as was environmental effects on food consumption in 0-group turbot. The 0-group turbot display a relatively restricted spatial distribution compared to flounder. This is possibly due to a more specialized diet, which may make them more vulnerable to habitat degradation, especially eutrophication as a strong negative correlation was found with the organic content in the sediment. The species show high temporal and spatial overlap when settling in July-September, with peak abundances in August, and at depths &lt;1 m. Both species display sedentary behavior within the nursery ground. Compared to flounder, turbot was more mobile potentially due to its restricted diet calling for extended searches. For turbot, feeding conditions appear to vary between size groups, which potentially could cause variations in survival between years through size-selective mortality. But, the predation may be low in central Baltic Sea as the abundance of the main predator, brown shrimp are comparatively low during flatfish occupancy. A significant positive relationship was found between the recruitment of turbot and flounder, which suggests that no inter-specific interactions during the juvenile stage affect recruitment. This co-variation also suggests that the recruitment of the species is determined by the same phenomena, potentially by large scale abiotic factors during the egg- and larval stage. For turbot, additional variability is potentially generated during the juvenile stage due to its relatively restricted food and habitat requirements. The specific habitat demands of turbot revealed in this thesis may be used to protect and restore essentially nursery grounds. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 3: Submitted. Paper 4: Submitted.
89

Energy intake of Common Guillemot, Uria aalge, chicks at Stora Karlsö, Sweden : influence of changes in the Baltic Sea

Enekvist, Elisabeth January 2003 (has links)
Observations of feeding behaviour of common guillemots, Uria aalge, in June 2002 at the island Stora Karlsö in the Baltic Sea proper, and measurements of morphology and energy density in the prey fish sprat, Sprattus sprattus, showed that fish delivered to chicks at present are shorter and weigh less than in the 1970s. Long lasting attending periods and a feeding rate of 4.6 feeds per day indicate that parents are feeding their chicks at a maximum rate. Because of a decline in the energy density in sprat (22.4 kJg-1 dry weight) the daily energy intake of common guillemot chicks have declined noticeably. This could probably explain the observed decrease in fledging body weight of chicks through the 1990s. Baltic common guillemots do not seem to be able to select more energy-dense prey sizes or to switch to other prey species.
90

Pathological changes in seals in Swedish waters : the relation to environmental pollution : tendencies during a 25-year period /

Bergman, Anders January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2008. / Härtill 6 uppsatser.

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