Earlier studies on the relationship between mercury concentration in fish – or alternatively bioavailability of mercury in aquatic systems – and different abiotic oceanographic factors such as water temperature, pH and salinity, have shown that such associations often exist. The results are not always consistent between studies, however. The aim of this study is to investi­gate if this type of relationships can be established in Baltic herring, Clupea harengus, with the use of temporal monitoring data from the northern Bothnian Bay (northern Sweden), compiled within Swedish monitoring programmes. The abiotic factors being assessed in this study are water temperature, salinity, dissolved oxygen, pH and measurements of nutrient content in the water; phosphate, total phosphorus and total nitrogen. Relationships between these parameters and mercury concentration in herring were investi­gated using multiple linear regression. Generally however, relationships were absent, and only one significant association was found, a positive relationship between total phosphorus in water and herring mercury load. Difficulty to reveal relationships in the presence of confoun­ding factors, which cannot be controlled for when using monitoring data from the field, is suggested as one reason for the absence of such relationships. Furthermore, the somewhat incomplete monitoring data of abiotic factors likely made it hard to detect any relationships.

Arctic soils store half of the global soil organic carbon (OC) pool and twice as much C as is currently present in the atmosphere. A considerable part of these carbon pools are stored in permafrost. Amplified climate warming in the Arctic will thaw permafrost and remobilize some of these substantial carbon stocks into the active carbon cycle, potentially causing positive feedback to global warming. Despite the global importance of this mechanism, our understanding of the fate of these thawing organic carbon (OC) pools is still poor, particularly regarding its degradation potential. This makes good estimates on greenhouse gas emissions versus coastal reburial impossible. This doctoral thesis aims to improve our understanding on the fate of high-latitude terrestrial OC during fluvial and coastal transport. In two study regions, the Bothnian Bay and the East Siberian Sea, we apply a wide range of bulk, molecular and isotopic geochemical analyses to reveal information on sources, age, degradation and transport routes. Our results show that both study regions receive and store large amounts of terrestrial OC, largely derived from peatlands (paper I, II and IV). This terrestrial matter undergoes extensive degradation in both the water column and surface sediments (paper I, III and IV). Surface sediments in the East Siberian Sea show a offshore-decreasing input of riverine OC and a considerable and constant input of OC from coastal erosion. The strong imprint of rapidly settling coastal OC far out on the shelf may be explained by a strong benthic boundary layer transport in combination with offshore ice-transport and selective preservation of erosion OC compared to riverine OC (paper IV). Molecular radiocarbon data allowed us to distinguish between two (sub-)Arctic soil OC pools that show a remarkably different susceptibility to degradation upon arrival in the coastal system; a young and easily degradable pool originating in surface peatlands, and an old and recalcitrant pool originating in deep mineral soils and coastal mineral Pleistocene deposits (paper III and IV). Our first estimates suggest that, in the Bothnian Bay coastal system, mineral soil OC is at least 20 times less susceptible to degradation than peatland OC (paper III). Hence, a considerable part of the thaw-released mineral OC pool may simply be relocated to coastal sediments instead of being emitted to the atmosphere. / At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Accepted. Paper 4: Manuscript.

Abstract Many plant species inhabiting the seashore meadows of the Bothnian Bay, especially early successional ones, have become threatened. Isostatic land uplift creates virgin land for early successional species to colonise. However, at the same time it gradually elevates the habitat and eventually makes the habitat unsuitable for them. Disturbances of the waterfront may slow down succession and create new empty sites. In order to persist on the shores, pioneer species have to be able to colonise new sites by seeds, vegetative propagules or growth. In this thesis I studied the status of an endangered early successional grass species, A. fulva var. pendulina, at the Liminka Bay. According to a matrix population model based on eight years of observations (1992–1999), the population seemed not to be in immediate danger of extinction. However, simulations based on four-year field observations (2000–2003) indicated that if the current trend continues, the species will decrease considerably in area in the next 30 years. In the field studies no seedlings or viable seeds of A. fulva were found. In spite of this, high genotypic diversity was found in the A. fulva population, suggesting that sexual reproduction has taken place at some time during the history of the population. Analysis of the population structure revealed a low level of genotypic differentiation between subpopulations and significant sub-structuring within subpopulations. The overall pattern of genetic variation suggests that the population has characters of both stepping-stone and metapopulation models. The results of the study on the ability of a seashore plant Potentilla anserina ssp. egedii to change its allocation of resources to sexual and vegetative reproduction according to competitive stress implied that the species can modify the allocation of resources to different life-history traits. For a plant living in disturbance-prone environment, it may be beneficial to be able to rapidly track the competition-free space formed by disturbances by changing its reproductive pattern. Management studies on three endangered seashore plant species showed that deterioration of suitable habitats of A. fulva and Primula nutans var. jokelae could be slowed down by management, and the vegetative and/or sexual reproduction of these species was enhanced. However, in the case of Puccinellia phryganodes, no positive response to management was observed.

Abstract Many waders are in decline, and the number of endangered species and populations is increasing. Their protection and management requires knowledge of both ecological and genetic state of the populations. In this thesis, I studied the distribution-wide genetic variation, structure and phylogeography of the Temminck’s Stint (Calidris temminckii) and Terek Sandpiper (Xenus cinereus) using microsatellites and sequence data from the mitochondrial control region and cytochrome oxidase I gene. I compared these regionally endangered species to other waders with varying evolutionary histories, breeding systems and habitat preferences to examine the levels of genetic variation and structure at different spatial scales. In addition, I studied the genetic structure of the endangered Baltic population of the Southern Dunlin (Calidris alpina schinzii) with microsatellites. I used genetic information in all three study species to determine units for conservation. The Temminck’s Stint and Terek Sandpiper, both not restricted to the Arctic, had low distribution-wide structuring. They also had quite low levels of variation when compared to other species breeding at similar latitudes, indicating reductions in population sizes during past climate changes. Especially the peripheral breeding populations were differentiated and showed signs of inbreeding and genetic drift when compared to the main range. The Temminck’s Stint populations at the Bothnian Bay and Yakutia, and Terek Sandpiper populations in Finland and Belarus, should be treated as separate management units. The broader interspecific comparison of waders suggests that habitat availability, mating system and the extent of philopatry may affect the genetic composition of species. The genetic analyses of the Southern Dunlin indicated strong effects of philopatry and inbreeding throughout the range. Local subpopulations at the Bothnian Bay and in Sweden need to be considered as separate management units. Management efforts at the Baltic should be focused on increasing connectivity and providing large enough breeding habitats for potential immigrants and recruits. / Tiivistelmä Useat kahlaajapopulaatiot ovat pienentyneet ja uhanalaistuneet maailmanlaajuisesti. Lajien ja populaatioiden ekologiaa ja genetiikkaa on tunnettava, jotta suojelutoimia voidaan kohdistaa oikein. Tutkin väitöskirjassani lapinsirrin (Calidris temminckii) ja rantakurvin (Xenus cinereus) geneettistä rakennetta, muuntelua ja fylogeografiaa levinneisyysalueen laajuisesti mikrosatelliittien ja mitokondrion kontrollialueen ja sytokromioksidaasi I -geenin sekvenssien avulla. Tutkin, mitkä tekijät vaikuttavat geneettisen rakenteeseen ja muunteluun vertaamalla näitä lajeja muihin kahlaajiin, joilla on erilaisia lisääntymisstrategioita, jotka pesivät vaihtelevissa ympäristöissä ja joista monet eroavat toisistaan myös fylogeografialtaan. Lisäksi tutkin Itämeren rannalla pesivän etelänsuosirrin (Calidris alpina schinzii) geneettistä populaatiorakennetta mikrosatelliittien avulla. Käytin geneettistä tietoa hyväksi luonnonsuojeluyksikköjen määrittämisessä kaikille kolmelle tutkimuslajilleni. Lapinsirrin ja rantakurvin fylogeografinen historia oli samankaltainen. Geneettisen muuntelun määrä oli vähäisempää verrattuna muihin, samankaltaisissa ympäristöissä pesiviin kahlaajiin. Molemmat lajit ovat todennäköisesti kärsineet historiallisten ilmaston-muutosten aiheuttamasta populaatioiden pienenemisestä. Erityisesti levinneisyysalueen reunoilla pesivät populaatiot olivat erilaistuneita, ja niissä näkyi sukusiitoksen ja geneettisen satunnaisajautumisen merkkejä. Perämeren ja Jakutian lapinsirri- sekä Valko-Venäjän ja Suomen rantakurvipopulaatioita tulee kohdella erillisinä suojeluyksiköinään. Vertailu muihin kahlaajiin osoitti, että niin pesimä- ja talvehtimisalueiden laajuus kuin lisääntymisstrategiat ja paikkauskollisuus voivat vaikuttaa lajien geneettiseen koostumukseen. Etelänsuosirrin geneettiset analyysit paljastivat merkkejä sukusiitoksesta, joita paikkauskollisuus ja populaatioiden pienuus ovat voimistaneet. Perämeren ja Ruotsin populaatioita tulee kohdella erillisinä suojeluyksiköinään. Suojelutoimet on kohdistettava tarpeeksi suurien, hyvälaatuisten pesimäpaikkaverkostojen ylläpitämiseen.

One of the challenges today ́s planners face with the urbanization is how to adapt the city to the climate changes, with the increasing precipitation that causes flooding. The concept of Sustainable stormwater management aims to prevent flooding and ensure good water quality, which complies with the EU Water Framework Directive. The aim of this thesis is to investigate how Sustainable stormwater management and climate adaption is implemented in municipal planning in the Bothnian Bay Water District and to map the prevailing conditions and obstacles that may occur. Semi-structured interviews were conducted with municipal planners in Luleå, Umeå, Haparanda, Kiruna, Boden, Piteå and Skellefteå. The answers were analyzed using a deductive thematic analysis method. The interview answers were coded at different levels with the research questions as a focus. This resulted in main themes and subcategories. The result shows that five of seven interviewed municipalities are in the process of implementing Sustainable stormwater management. The municipalities are aware of pollution in stormwater and the importance of good water quality, the goal is to achieve a natural flow of stormwater. Most of the municipalities work with the stormwater issue across administrative boundaries in collaboration. The climate adaptation work in the municipalities consists mainly of rainfall mapping and elevation of buildings. The greatest obstacles to the implementation are unclear division of responsibilities, lack of resources and knowledge and the question of land use. Regarding the municipality's size and geographical locations, factors such as terrain, watercourses / recipients, demographics, finances and human resources are of importance. / En av utmaningarna som urbaniseringen för med sig och som dagens planerare måste hantera är hur staden ska anpassas till klimatförändringarna; med den ökande nederbörden som orsakar översvämningar. Konceptet Långsiktigt hållbar dagvattenhantering syftar till att förhindra översvämningar och säkerställa god vattenkvalitet, vilket överensstämmer med EU: s Vattendirektiv. Syftet med denna studie är att undersöka hur Långsiktigt hållbar dagvattenhantering och klimatanpassning implementeras i kommunal planering i Bottenvikens vattendistrikt och att kartlägga rådande förutsättningar och hinder för denna implementering. Semi-strukturerade intervjuer genomfördes med tjänstepersoner i Luleå, Umeå, Haparanda, Kiruna, Boden, Piteå och Skellefteå. Svaren analyserades med hjälp av en deduktiv tematisk analysmetod. Intervjusvaren kodades på olika nivåer med forskningsfrågorna som fokus. Detta resulterade i huvudteman och underkategorier. Resultatet visar att fem av sju intervjuade kommuner arbetar med att implementera Långsiktigt hållbar dagvattenhantering. Kommunerna är medvetna om föroreningar i dagvatten och vikten av god vattenkvalitet, målet är att uppnå ett naturligt flöde av dagvatten. De flesta av kommunerna arbetar i förvaltningsövergripande samverkan med dagvattenfrågan. Klimatanpassningsarbetet i kommunerna består främst av skyfallskartering och höjdsättning av byggnader. De största hindren för implementeringen  är oklar ansvarsfördelning, brist på resurser och kunskap och frågan om markanvändning. När det gäller kommunens storlek och geografiska läge är faktorer som terräng, vattendrag / recipienter, demografi, finansiering och humankapital av betydelse.