Convective snow bands forming over the Baltic Sea can result in heavy precipitation along the Swedish east coast. Forecasting these events well is of great importance to prevent road traffic injuries, increased pressure at hospitals and cancelled bus traffic. This thesis project aims to evaluate the performance of the high-resolution non-hydrostatic convection permitting model HIRLAM ALADIN Reasearch on Mesoscale Operational NWP In Euromed (HARMONIE) in simulating convective snow bands. Its horizontal respresentation of precipitation rates, area, placement and timing was examined in a case study of two events. The case of 2007 during the 12-14th of November, formed over the Gulf of Finland and resulted in Nynäshamn receiving ≥ 55 mm precipitation during the 37 hours long event. Areas south of this precipitation maxima also recieved heavy precipitation. The second case, 21-23rd of March 2008, formed over the Gulf of Bothnia during north-easterly  winds and resulted in a total precipitation of 10 mm at Gävle. The precipitation maxima was observed offshore, north of Gävle, with ≥ 16 mm precipiation in 34 hours. Convective snow bands were also observed over Vänern and Vättern in both cases.  HARMONIE simulated convective snow bands well in terms of intensity, timing, placement and area, in both cases, compared to datasets from radar, radar with merged gauge data and separate observational data from weather stations. Areas south of the local maxima at Nynäshamn in the case of 2007 were however overestimated by a total of 10-15 mm, most likely due to a simulated shift in wind direction during some of the most intense hours. In the case of 2008 the model also captured weak convective snow bands at Vänern and Vättern accurately in terms of precipitation area, timing and accumulated precipitation. Further case studies of snow bands are however necessary to obtain a more comprehensive view of the performance of HARMONIE.

When implementing major European transport corridors, such as the Core network corridors (CNC) which is a part of the European Trans-European Network for Transports (TEN-T), the number of stakeholders affected is huge. A governance framework for the CNC’s implementation was introduced in EU Regulation No. 1315/2013, and is now being enacted. Sustainable development and stakeholder involvement are crucial areas in the implementation. This interview study investigated the need for complementary governance, here meaning governance in addition to the governance framework set in the regulation. The interviews involved 23 individuals from the Baltic Sea Region, who are affiliated to the four categories public authority, infrastructure organisation/company, private company and other organisation. The results confirm the importance of an inclusive approach. Further, the results showed a need to ensure that all three social, economic and ecological dimensions of sustainability are considered. Summarising the interview results, four areas for attention in the further CNC implementation process were identified: more and directed information, extended involvement of private sector transport stakeholders, extended involvement of regional and local stakeholders, and involvement of stakeholders located geographically outside the immediate corridor. Complementary governance can be a tool to address these areas, as governance structures and processes can involve stakeholders and steer towards desired outcomes. The interviewees own ideas for complementary governance are presented in this paper. The CNC implementation is currently an on-going process and these results will be further utilised in the process, as a basis for stakeholder discussions of changes in practice.

Within temperate coastal seascapes, macroalgae provide habitats for different organisms such as invertebrates and fish. In analogy to seagrass meadows, macroalgae beds are known for their importance as fish nurseries. However, within the Baltic Sea the importance of the canopy forming macroalgae Fucus vesiculosus for coastal fish communities, especially the juveniles, is unclear. In order to address this knowledge gap, fish communities in areas with and without F. vesiculosus were investigated around Askö, an island in the archipelago of the Baltic Sea. Sites were subjected to different exposures (sheltered, exposed or very exposed) and three different methods were used for sampling (underwater visual census (UVCs), beach seine netting and remote underwater videos (RUVs)). Overall, fish community composition differed significantly among locations and fish abundance and fish biomass were significantly higher in sites with F. vesiculosus than sites without. There was no significant relationship between algae cover or habitat complexity and fish abundance/biomass in sites with F. vesiculosus. Fish behaviour differed between sites with and without F. vesiculosus, with fish feeding more in sites with F. vesiculosus and traveling more in sites without F. vesiculosus. Only one location, Knabberskär, had significantly higher species richness in F. vesiculosus than in sites without F. vesiculosus. There were no differences in juvenile abundance among sites with or without F. vesiculosus and abundance of adult fish was higher than juvenile fish, regardless of location, site or species. Mean invertebrate abundance was a twice as high in the sheltered location Husbåtsviken than in Knabberskär. Higher fish abundance, fish biomass and species richness in sites with F. vesiculosus compared to sites without, suggest that macroalgae may play an important role in the Baltic Sea, however it might not be as important for juvenile fishes as predicted. The three different sampling methods provided similar results for fish abundance, but not for fish biomass. Continued studies where the relationship between fish communities and aspects of F. vesiculosus structure (such as canopy height) as well as linkage with other habitats is recommended for further understanding and better protection of F. vesiculosus habitats.

Energy balance of large-scale and small-scale scenarios of macroalgae harvesting for biogas production was assessed from the energy balance perspective. Evaluation was based on primary energy Input Output (IO) ratio where all primary energy inputs into the stages of the process life-cycle were summarized and divided by the final energy output from the system. Estimations were made for three cases of possible methane yield from macroalgae as well as for different scenarios of macroalgae co-digestion with other feedstock. Anaerobic digestion of macroalgae as a single substrate both on a small- and large-scale is energy efficient only in case when their methane potential is at the average or high level with the IO ratio of 0.47 and 0.32 correspondently. In general co-digestion with other substrates is more preferable with respect to process condition and energy balance. Large-scale scenario is more stable and efficient than small-scale with the lowest IO ratio for co-digestion with crops. This is explained by the fact that biogas plant operation is among the most energy demanding stages which on the small-scale requires about 65 % of the input energy when this number for large-scale plant does not exceed 28 %. Energy inputs into digestate handling, feedstock pre-treatment and biogas upgrading, that are next most energy consuming stages, is greatly affected by the assumptions made about amount of substrate, produced biogas and transportation distance. When considering the maximal distance between macroalgae harvesting point and biogas production site and to which at which the energy balance remains positive then digestate handling becomes the most energy demanding process stage.

<p>NR 20140805</p>

Eutrophication of the Baltic Sea has been an issue for decades and the pollution constantly continues with oxygen deficient bottoms and a damaged marine life as a result. One of the main causes of eutrophication are elevated levels of the nutrient phosphorus. Phosphorus leaks to the sea from various human activities such as agriculture, animal farming and sewage. In Sweden, the onsite wastewater treatment systems are a big problem since they load the Baltic Sea with nearly as much phosphorus as all Swedish municipal wastewater treatment plants. The need for a reduced impact on the Baltic Sea is major and the individual wastewater treatment systems must therefore be looked over. While phosphorus is a contributing factor to eutrophication, it is one of the most important nutrients for all life. Phosphorus builds up our DNA, helps transport of various substances in and out of our cells and provides energy to the cell's processes. We would simply not be able to survive without phosphorus. We ingest phosphorus through the food we eat, which in turn is dependent on fertilizers containing phosphorus. Phosphorus is mined from phosphate ore and the majority of it is used to produce fertilizers. Unfortunately, phosphate ore is not a finite resource and in the last few years it has been realized that the economically extractable phosphorus is a dwindling resource. To be able to produce food for the world's growing population, we need to find ways to recycle phosphorus. In individual drainage systems there is a large potential to catch up phosphorus and then reuse it on agricultural land. This thesis deals with the problems of onsite wastewater treatment systems and suggests measures to improve their status. Ways to recycle phosphorus in combination with having a well-functioning drainage is being investigated and difficulties about the regulations are being discussed. To recover phosphorus and at the same time reduce the burden on the environment should be seen as an incredibly important action, since our sea’s health is acute but lack of the nutrient could have devastating consequences.

For decades the Baltic Sea has been subject to eutrophication due to heavy anthropogenic nutrient loads on the aquatic ecosystem. Quantitative projections of its effects require an understanding of its driving mechanisms, i.e., the hydrodynamics that are responsible for the physical transport and mixing and the biogeochemical nutrients pathways within the algal ecosystem and between the particulate and dissolved phases in the water and in the sediments. A simple basin-scale hydrodynamic framework is set for the Gulf of Finland to test different descriptions of the biogeochemical transformations and determine the most robust modelling strategy. A recently developed criterion to determine the occurrence of anoxic events, based on the amount of fresh carbon detritus in the sediments is implemented in comparison with the classical criterion based on the oxygen concentration in the bottom water. Time-averaging of the hydrodynamics over larger than daily intervals is proved to hinder the capture of rapid mixing events jeopardizing irremediably the water quality simulation. The new carbon based criterion for anoxia shows a better dynamic response and is less sensitive to the model’s internal parameters. An internal source in the sediments correlated to the amount of fresh detritus, to represent the release of iron-bound phosphorus is confirmed as a versatile modelling assumption.

Eutrophication is a major problem in the Baltic Sea and is the result mainly of the increase of the anthropogenic nutrient loading. Thus, the links among water quality, sediments, and eutrophication have to be understood in order to predict the consequences of our actions and of the climate change on the Baltic Sea. Therefore, water quality models that take into account the hydrodynamics have to be developed to help policy makers. In that perspective, the Kiirikki model, an ecosystem and sediment model, coupled to a box approach has been used to describe the water quality of the Baltic Sea. The latter has been divided into twelve sub-basins according to the topography, each of them separated into two vertical layers. The Kiirikki model has been implemented on each sub-basin and the hydrodynamics are used to link sub-basins between them. After calibration, it can be seen that the model results are consistent with the monitoring data for the southern part, even if the dissolved inorganic nitrogen levels are too high during the winter and some phase shifts are observed. For the northern part, the primary production is well modelled but there is an offset concerning the dissolved inorganic nutrient. Thus, it can be concluded that the implementation of the Kiirikki model is a realistic tool to describe the water quality and eutrophication of the Baltic Sea. However, the differences indicate that the Baltic Sea model cannot be use for policy making yet and more work is needed to improve the model such as a global sensitivity analysis as well as the use of site specific parameters.

The Carbon dioxide (CO2) concentration in the atmosphere has increased dramatically since the start of the industrialisation. The effects that the increase of CO2 has on the future climate are still not fully investigated. CO2 in the atmosphere contributes to the, for all life on earth, necessary greenhouse effect. It is confirmed that higher CO2 concentration in the atmosphere increases the green house effect, which results in higher temperature. The main source to the increase of CO2 is burning of fossil fuels. The change in land use is also a contribution to the increase of the CO2 concentration in the atmosphere. The largest sinks of CO2 are organic consumption and oceanic uptake. The organic consumption of CO2 varies a lot at higher latitudes due to the difference in vegetation between the seasons. During the warmer seasons the consumption of CO2 is large and during the winters the consumptions of CO2 is practically zero. The ocean uptake of CO2 varies also a lot during the year because the CO2 dissolves more easily in cold water. The purpose of this study is to analyse CO2 concentration and air-sea fluxes of CO2 measured at Östergarnsholm, a small flat island east of Gotland in the Baltic Sea, and compare the results to previous studies. The CO2 concentration data was collected between 1997 – 1999 and 2001 – 2003. The CO2 flux data was collected between 2001 and 2003. The analysis of the CO2 concentration showed that for the period 1997 to 1999, the CO2 concentration at Östergarnsholm was lower than for the reference series from a Polish site in the Baltic Sea. A correction was made by adding 27 ppm to the Östergarnsholm series. The annual fluctuations of CO2 concentration at Östergarnsholm are significant (about 40 ppm). During the summer 1998, the expected decrease was not as large as it should be because of the El Niño outbreak 97/98 and the locally cold and rainy summer. The direct measured CO2 fluxes were corrected with the well known Webb correction before they were analysed. The CO2 fluxes are wind dependant – higher wind speed give higher CO2 flux. The CO2 fluxes are also dependant of the difference in partial pressure between the air and the water. Parameterised CO2fluxes were calculated and compared to the direct measured CO2 fluxes. The parameterisations use a quadratic as well as a cubic wind dependency. To calculate the parameterised CO2 fluxes, a fixed value of the difference in partial pressure between the air and the water was used because the CO2 in the water was not measured. The parameterised CO2 fluxes wind dependency agreed with the direct measured CO2 fluxes. / Koldioxid(CO2)-koncentrationen i atmosfären har ökat stadigt sen början av industrialiseringen. Effekten som de ökade CO2-halterna kommer ha på framtidens klimat är ännu inte helt utrett. CO2 bidrar till den livsviktiga växthuseffekten. Det är en ökning av växthusgaser, bland annat CO2, som leder till en ökning av växthuseffekten. Ökad växthuseffekt leder till högre temperatur på jorden. Den största ökningen av CO2 i atmosfären beror på förbränning av fossila bränslen. Även förändringen i markanvändning leder till ökade halter av CO2. De största sänkorna av CO2 är den organiska konsumtionen av CO2 och havens upptag av CO2. Den organiska konsumtionen av CO2 varierar mycket under året och är som störst under de varmare månaderna. Havens upptag av CO2 varierar också mycket under året eftersom havens förmåga att lösa CO2 beror på vattnets temperatur. Syftet med den här studien är att analysera CO2-koncentrationen och CO2-flödena mellan hav och luft på Östergarnsholm, en liten, låg ö öster om Gotland. Resultaten jämförs med tidigare studier. CO2-koncentrationsdata samlades in mellan 1997 – 1999 och 2001 – 2003. CO2-flödesdata samlades in mellan 2001 och 2003. Analysen av CO2-koncentrationen visar att under perioden 1997 till 1999 är CO2- halterna för låga på Östergarnsholm. En korrektion gjordes genom att lägga till 27 ppm till de uppmätta CO2-halterna. Årsvariationerna av CO2-halterna är mycket tydliga men sommaren 1998 sjunker inte CO2-halten till så låga värden som de borde vara. Att CO2-halterna inte sjönk mer beror dels på El Niño-utbrottet 97/98 och dels på den lokalt kalla och regniga sommaren. De direkt mätta CO2-flödena korrigerades med hjälp av den välkända Webbkorrektionen innan de analyserades. CO2-flödena är beroende av vindhastigheten – högre vindhastighet ger högre CO2-flöden. CO2-flödena beror också på skillnaden i CO2-halt mellan luften och havet. Parameteriserade CO2-flöden beräknades och jämfördes med de direkt mätta CO2-flödena. De parameteriserade CO2-flödena beräknas antingen med kvadratiskt eller kubiskt vindberoende. För att beräkna parameteriserade CO2-flöden användes ett fast värde på skillnaden i CO2-halt mellan luften och vattnet eftersom CO2-halten i vattnet inte mäts. De parameteriserade CO2- flödenas vindberoende stämde överrens med de direkt mätta CO2-flödena.

Eutrophication is one of the greatest threats for the Baltic Sea, and one of its more critical consequences is bottom water hypoxia. Nutrient enrichment and oxygen-depletion affect both the deep central basins and a number of coastal areas, even though strategies for nutrient reduction have lately been implemented. In order to better understand why those threats are expanding and formulate more effective remediation strategies two main achievements are needed: (1) new data on benthic nutrient dynamics should be available in order to develop updated budgets for sensitive Baltic areas; (2) the main transformation processes and their regulation mechanisms (i.e. oxygen availability, presence of macrofauna, different organic loading scenarios) should be better constrained. Paper I was able to demonstrate that re-oxygenation of previously anoxic sediment has a positive effect on the ecosystem because of better retention of nutrients and efficient conversion of fixed nitrogen to nitrogen gas. Sediment colonization by the invasive genus Marenzelleria counteracts some of the positive aspects provided by benthic oxygenation (in particular, nutrient retention, N2 loss). A possible explanation for this reversal can be that Marenzelleria does stimulate anaerobic more that aerobic metabolism. Results from Paper II suggest that at the outermost stations of Himmerfjärden denitrification follows a pronounced seasonal pattern, primarily regulated by bottom water temperatures. At the innermost and impacted site oxygen level in the bottom water varies considerably during the year and causes denitrification/DNRA predominance to be the main nitrate reduction pathway. On an annual scale, the net amount of lost N2 is comparable at the four sampling sites and accounts for 96% of the total DIN discharged from the sewage treatment plant, suggesting that denitrification in the estuarine sediment acts as a major nitrogen sink for external N inputs.