Thesis--Copenhagen. / "Niels Haislund ... has undertaken the translation."--Pref. "Dansk resumé": p. [481]-490. Bibliography: p. [467]-477.

Målet med denna studie var att undersöka inverkan av brus, normaliseringen av Laplacianen, antalet kluster k och antalet grannar i närhetsgrafen knn på en implementation av spektral klustring. Med hjälp av den framtagna klustringen skulle lämpligheten att använda spektral klustring i en oceanografisk tillämpning utvärderas. Undersökningen utfördes på SMHIs data från två väderstationer under två olika tidpunkter: Vinga (Juli, 2019) och Visby (Juli, 1987). Datan behandlades med hjälp av MATLABs zscore-funktion och användes sedan i den spektrala klustringsalgoritmen. Klustringens kvalitet avgjordes genom att betrakta den spektrala tätheten, beräkna den genomsnittliga variansen mellan kluster och granska egenvärdenas storlek. Resultaten visade att bruset kunde försummas, att den icke-normaliserade Laplacianen var att föredra samt att k = 12 och knn = 15 var ett optimalt parameterval förVinga 2019. Dessutom tycktes vissa oceanografiska fenomen, såsom tidvatten och Ekmaneffekten, återfinnas i klustringen. Slutligen tycks spektral klustring vara en lämplig metod för enklare oceanografiska tillämpningar, även om valet av parametrar måste testas för varje applikation av algoritmen.

The Baltic Sea is a sensitive and unique ecosystem that has been strongly affected by human activity in the area. It is an important cultural and natural resource that contributes with several economic benefits. Among the many documents aiming to protect the Baltic Sea, this thesis concerns two of the action plans; An Agenda for the Baltic Sea Region – Baltic 21 and HELCOM Baltic Sea Action Plan, which are two of the most recognised documents aiming at protecting the Baltic Sea area. The two documents was analysed using three different types of text analysis. As the main goal in all environmental protection is to urge preventive action in protecting the environment, the two documents will be analysed with the aim of investigating whether preventive action is advocated in the protection of the Baltic Sea, even though the region is threatened and have many problems from an environmental point of view. The two documents differ structurally as their approaches differ. The HELCOM Baltic Sea Action Plan (BSAP) has an ecosystem approach, whiles the Baltic 21 has sustainable development as its primarily approach. The results of the study further show that preventive action is advocated in both documents. However, the BSAP presents a cleared preventive approach and suggests more preventive action than Baltic 21. Baltic 21 lack a clear connection to the Baltic Sea and instead focus in the whole Baltic Sea area. There are few clearly preventive action presented in the protection of the actual Baltic Sea in Baltic 21. Instead the Baltic 21 shows a vague argumentation and few actions aiming at preventing environmental harm to the Baltic Sea.

<p>The Baltic Sea is a sensitive and unique ecosystem that has been strongly affected by human activity in the area. It is an important cultural and natural resource that contributes with several economic benefits. Among the many documents aiming to protect the Baltic Sea, this thesis concerns two of the action plans; An Agenda for the Baltic Sea Region – Baltic 21 and HELCOM Baltic Sea Action Plan, which are two of the most recognised documents aiming at protecting the Baltic Sea area. The two documents was analysed using three different types of text analysis.</p><p>As the main goal in all environmental protection is to urge preventive action in protecting the environment, the two documents will be analysed with the aim of investigating whether preventive action is advocated in the protection of the Baltic Sea, even though the region is threatened and have many problems from an environmental point of view.</p><p>The two documents differ structurally as their approaches differ. The HELCOM Baltic Sea Action Plan (BSAP) has an ecosystem approach, whiles the Baltic 21 has sustainable development as its primarily approach. The results of the study further show that preventive action is advocated in both documents. However, the BSAP presents a cleared preventive approach and suggests more preventive action than Baltic 21. Baltic 21 lack a clear connection to the Baltic Sea and instead focus in the whole Baltic Sea area. There are few clearly preventive action presented in the protection of the actual Baltic Sea in Baltic 21. Instead the Baltic 21 shows a vague argumentation and few actions aiming at preventing environmental harm to the Baltic Sea.</p>

The aim of this paper is to reveal how the European – Russian political cooperation in the common Baltic Sea Region developed over the last twenty years, ending up at the recently adopted European Union Strategy for the Baltic Sea Region, which excludes Russian participation. This single case study is divided into two well-defined historical periods: starting from the fall of the Berlin Wall until the Eastern Bloc European enlargement and from 2004 to the adoption of the European Union Strategy for the Baltic Sea region in 2009; where comparison and process-tracing methods are applied to connect different variables that matter for clarifying the current state of relations. Furthermore, the analysis is conducted with the help of Constructivist and Neo-Realist theories for two purposes – to achieve stronger scientific explanation and to avoid too loose interpretation of the events. The results show that the Strategy for the Baltic Sea Region is often seen and understood differently by the various political actors, but consequently this leads to a situation in which the role of Russia in the common region remains unclear. When it comes to defining the Russian position today, the Baltic Sea Region provides a good climate for collaboration but so far, the European Union has failed to recognize that the Russian Federation although with a limited access to the sea, remains an actor that should not be ignored. Russia, as well appears confused about its overall foreign policy towards the European Union. Nevertheless, another significant outcome reveals that the levels of regional cooperation have been continuously increasing over the last twenty years, which is an indicator that the Russian presence did not diminish. Finally, the study suggests the European Union Strategy for the Baltic Sea Region is perhaps the beginning of a new tendency towards macro-regional policy development, which will play a future important role in the international relations.

Commercial fishing in the Baltic Sea has led to decrease in abundance of large predatory fish and as a result the predation pressure on smaller fish species has been reduced. Three-spined stickleback (Gasterosteus aculeatus) is among the species that have benefited from reduced predation pressure. Sticklebacks are a small fish species that spends its juvenile stage in coastal habitat and its adult stage in the open sea with a yearly migration from the sea to coastal habitat and lakes for spawning. Sticklebacks have been shown to have a negative effect on fry of coastal species, such as perch (Perca fluviatilis). Therefore an increase in stickleback abundance, as a consequence of reduced predation pressure, can potentially further reduce abundance of fry of coastal species, such as perch. On the other hand sticklebacks could be subject to predation from adult perch. This two-species interaction is studied in the perspective of general ecological IGP (intra guild predation) theory. In order to determine how the observed increase of three-spined sticklebacks negatively or positively affects the growth of different stages of perch, a time series of operculum bones from perch collected by the coastal monitoring program prior to the increase of sticklebacks and up until present was analyzed. Three areas along the Swedish coast showing increased stickleback abundance (Gaviksfjärden, Norrbyn and Holmön) were compared to areas that had no sticklebacks or only a small increase in abundance (Kinnbäcksfjärden, Råneåfjärden, Långvindsfjärden) prior and after the general increase in stickleback density. In addition to the growth analysis, a dietary analysis of perch was carried out in order to determine to what extent perch utilize sticklebacks as a food source. I found that there were significant differences in regard to perch growth between the two time periods; however there was no significant difference in growth between the control areas and the stickleback areas except for perch of medium size. Further, this difference in growth between the control and stickleback areas was present both before and after the stickleback increase and could therefore not be tied directly to stickleback increase. Consequently, results from a multiple regression showed that stickleback abundance was not able to significantly explain the observed changes in perch growth. The dietary analysis showed that larger and intermediate perch tend to consume sticklebacks as well as benthic fauna and other fish species while smaller perch tended to feed exclusively on smaller invertebrates. This study concluded that the increase in stickleback abundance had only a very weak effect on perch growth.

Microorganisms play central roles in planet Earth’s geochemical cycles, in food production, and in health and disease of humans and livestock. In spite of this, most microbial life forms remain unknown and unnamed, their ecological importance and potential technological applications beyond the realm of speculation. This is due both to the magnitude of microbial diversity and to technological limitations. Of the many advances that have enabled microbiology to reach new depth and breadth in the past decade, one of the most important is affordable high-throughput DNA sequencing. This technology plays a central role in each paper in this thesis. Papers I and II are focused on developing methods to survey microbial diversity based on marker gene amplification and sequencing. In Paper I we proposed a computational strategy to design primers with the highest coverage among a given set of sequences and applied it to drastically improve one of the most commonly used primer pairs for ecological surveys of prokaryotes. In Paper II this strategy was applied to an eukaryotic marker gene. Despite their importance in the food chain, eukaryotic microbes are much more seldom surveyed than bacteria. Paper II aimed at making this domain of life more amenable to high-throughput surveys. In Paper III, the primers designed in papers I and II were applied to water samples collected up to twice weekly from 2011 to 2013 at an offshore station in the Baltic proper, the Linnaeus Microbial Observatory. In addition to tracking microbial communities over these three years, we created predictive models for hundreds of microbial populations, based on their co-occurrence with other populations and environmental factors. In paper IV we explored the entire metagenomic diversity in the Linnaeus Microbial Observatory. We used computational tools developed in our group to construct draft genomes of abundant bacteria and archaea and described their phylogeny, seasonal dynamics and potential physiology. We were also able to establish that, rather than being a mixture of genomes from fresh and saline water, the Baltic Sea plankton community is composed of brackish specialists which diverged from other aquatic microorganisms thousands of years before the formation of the Baltic itself. / <p>QC 20150505</p>

<p>Övergödning utgör ett av de allvarligaste hoten mot Östersjöns miljö. Storleken av näringsbelastningen till havet behöver därför bestämmas med hjälp av tillgängliga matematiska modeller. Modellen ”Generalised Watershed Loading Functions” (GWLF), en ickedistribuerad parametermodell som uppskattar hydrologi och månatlig näringsbelastning, tillämpades på avrinningsområdet till Daugava som mynnar i Östersjön. Syftet med studien var att genom modellering av historisk transport av näringsämnen till Östersjön ta fram parametrar och indata som sedan kan användas vid applicering av GWLF på omkringliggande avrinningsområden. Data från 1990-talet användes för kalibrering av modellen och data från 1980-talet för validering. Årlig kvävebelastning modellerades med R2värdet 0,78 för kalibreringsperioden. Modellerad årlig kvävebelastning för valideringsperioden underskattades med ungefär 30 % vilket troligen beror på att kvävekoncentrationer i grundvatten och ytavrinning minskade mellan 1980- och 1990-talen.</p><p>Fosforbelastningen underskattades jämfört med rapporterade värden vilket troligen beror på att enskilda avlopp inte inkluderades och att rapporterade punktutsläpp är för låga.</p><p>Modifikationer av modellen föreslås för prediktion av näringsbelastningar under lång tid och behovet av harmoniserad, uppdaterad och lättillgänglig data för näringstransportsmodellering diskuteras.</p> / <p>Eutrophication is one of the most serious threats to the Baltic Sea environment. Nutrient loading into the sea therefore needs to be quantified by available mathematical models. The Generalised Watershed Loading Functions (GWLF), a lumpedparameter model that predicts hydrology and monthly nutrient loads, was applied to the Daugava River Basin, discharging into the Baltic Sea. The aim of the study was to model historic transport of nutrients into the Baltic Sea and thereby produce estimates of parameters and input data needed for a spatial extension of the GWLF to surrounding river basins.</p><p>Calibration data were taken from the 1990’s and validation data from the 1980’s. Yearly nitrogen loads were modelled with an R2 value of 0.78 for the calibration period. Predicted yearly nitrogen loads for the validation period were about 30 % lower than reported values, probably depending on decreasing groundwater and runoff concentrations between the 1980’s and 1990’s. Phosphorus loads were underestimated compared to reported values, the main reason probably being the exclusion of septic systems and too low reported point sources.</p><p>Modifications of the model are suggested for longterm predictions of nutrient loads and the need for harmonised, uptodate and generally accessible data for nutrient transport modelling discussed.</p>

Eutrophication caused by nutrient loads from human activities is considered as one of the most serious environmental threats to the Baltic Sea. Due to climate change, cyanobacterial blooms are expected to increase in the future. This could affect people’s utility of beach recreation negatively in countries surrounding the Baltic. Based on a web survey carried out in south-eastern Sweden, public’s reactions and attitudes to cyanobacterial blooms are analysed. Possible economic impact on Gotland of more widespread blooms are estimated, and public demand for better information is evaluated. The result shows that 30% of the respondents from south-eastern Sweden would consider cancelling their plans of travelling to Gotland with knowledge about forthcoming algal blooms around the island. Determinants of tourists’ tendency to cancel their travel arrangements are earlier negative experiences of algal blooms and concerns regarding their pets’ bathing. The annual local economic loss for Gotland’s tourism industry is estimated to between 15 and 221 million SEK. The median willingness to pay for a mobile application which provides one-day forecasts of algal blooms is 25 SEK on Gotland and 20 SEK in southeastern Sweden. Boat owners, people who visit beaches often and those who travel to Gotland frequently, are more likely to pay for the mobile application. People who think algal blooms are natural show less demand for information.

Temperature dependence of marine plankton respiration is an important factor in understanding the function and changes in the ecosystem of the ocean. The aim of this study is to test the temperature sensitivity (Q10) of plankton respiration. The oxygen optode method was used to measure plankton respiration. Natural water samples from the Baltic Sea was incubated at short (in situ +1, +2, +3°C) and long (in situ +5, +10, +20°C) temperature intervals with influence of dissolved organic matter (DOC). The Arrhenius equation and Q10-model was used to determine the temperature dependence (Q10) of respiration at different temperatures. There was a significant difference in Q10 between short temperature intervals at low temperatures (p=0,008) and long temperature intervals at higher temperatures. There was no significant difference between long and short temperature intervals when DOC was added (p=0,094). A significant effect could be seen with the DOC enrichment at low temperatures, where the Q10-values became significantly lower (p=0,002) after DOC addition. This effect could, however, not be seen at higher temperatures (p=0,117). Together with results from earlier studies it was concluded that the difference in temperature depends on the actual temperature and not the length of the interval. Lowered temperature dependence at raised DOC concentration, was the opposite of what was expected. The results suggest that the importance of temperature for CO2 emissions and development of hypoxia in the sea may have been underestimated.