β-N-methylamino-L-alanine (BMAA) is one of the more recently discovered bioactive compounds produced by cyanobacteria. BMAA is a non-protein amino acid reported present in human brain tissues of patients deceased from a neurodegenerative disease, such as Alzheimer´s disease or amyotrophic lateral sclerosis (ALS). This observation in combination with its neurotoxic effects in eukaryotes (in vivo and in vitro) and its potential to incorporate into (human) proteins, causing protein aggregation, suggests BMAA as a possible causative environmental agent for neurodegenerative diseases. Due to the ubiquitous nature of cyanobacteria with a wide occurrence in both aquatic and terrestrial environments, BMAA could be globally spread. Hence, investigations of a possible coupling between BMAA and neurodegeneration are urgently needed as well as to identify sources of BMAA in Nature. The aim of this thesis was to examine the potential occurrence of BMAA in bloom forming cyanobacteria of the Baltic Sea and its possible transfer to other organisms of this ecosystem. Of importance was also to reveal any likely routes for human BMAA exposure in the Baltic Sea region and to further investigate BMAA as a triggering agent for neurodegenerative diseases. Acknowledged difficulties of analysing BMAA in biological samples also inferred method development as part of the experimental studies. Investigating the role of BMAA in its producers was another purpose of the thesis, which may be crucial for future management of BMAA-producing cyanobacteria. By screening natural populations of the major filamentous bloom forming cyanobacteria of the Baltic Sea, we discovered the presence of BMAA throughout the entire summer season of two consecutive years, using a highly specific analytical method (liquid chromatography-tandem mass spectrometry; LC-MS/MS). BMAA was found to bioaccumulate in zooplankton and fish, as well as in mussels and oysters from the Swedish west coast. To improve the understanding of BMAA analyses in natural samples, the formation of carbamate adducts in the presence of bicarbonate was examined. Using two derivatization techniques in combination with LC-MS/MS, we could show that BMAA detection was not hindered by carbamate formation. Exogenously added BMAA inhibited nitrogen fixation in the model cyanobacterium Nostoc sp. PCC 7120, which was also hampered in growth and displayed signs of nitrogen starvation. Finally, BMAA was detected in cerebrospinal fluid in three of 25 Swedish test individuals, and represents the first confirmation of BMAA in the human central nervous system using LC-MS/MS as the primary analytical method. However, the association of BMAA to neurodegenerative diseases could not be verified as BMAA was present in both control individuals (two) and in one ALS-patient. Nevertheless, the finding of a known neurotoxic compound in the human central nervous system is alarming and potential consequences should be investigated. The discovery of the neurotoxic compound BMAA in Baltic Sea organisms, and in the central nervous system of humans potentially consuming fish from this ecosystem is concerning and warrants continued investigations of BMAA occurrence and human exposure. Further knowledge on the function and regulation of BMAA may help in developing strategies aiming to minimise human exposure. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p>

This thesis deals with the question of whether planktonic protits of the genus Dinophysis have permanent plastids (=chloroplasts) or practice kleptoplasty, i.e. acquire plastids via predation on other microorganisms. Sequencing the plastid 16S rDNA of Dinophysis spp. collected from 4 different geographical regions unveiled two different plastid genotypes within this genera: one that was found at all locations investigated, identical to that of the free-living cryptophyte Teleaulax amphioxeia, and another found only in the Greenland Sea, closely related to that of the cryptophyte Geminigera cryophila. Both types were found within the species D. acuminata. These findings imply that the plastids in Dinophysis spp. were not inherited from a common ancestor, but acquired from feeding. By using flow cytometry in combination with an acidotrophic probe, it was shown that 71 % of the cells in a D. norvegica population in the aphotic zone of the Baltic Sea had food-vacuoles. Dinophysis used to be regarded as a primarily phototrophic organism, and this was a higher proportion of cells with food-vacuoles than reported earlier. To further study if Dinophysis needs constant refill of new plastids from the environment, a new method combining flow-cytometry and quantitative real-time PCR was developed to compare the levels of nuclear and plastid DNA in different phases of the cell-cycle. Results showed that plastid acquisition in Dinophysis was uncoupled with the cell-cycle, which is different than the pattern seen in microalgal species with permanent plastids. Furthermore, when quantitative real-time PCR combined with flow-cytometry was used to follow D. caudata cultures during a 65 days starvation/feeding experiment, the cells first went through a steady decrease in plastid DNA during starvation. In contrast, after feeding on the ciliate Myrionecta rubra, plastid DNA in starved cells increased 7-fold, thereby directly revealing the kleptoplastic behavior. The main conclusion from this thesis is that Dinophysis cells are actively taking up kleptoplastids from the ciliates on which they feed, and that kleptoplasty is an important key to understand Dinophysis ecology. Part of this thesis work has also been dedicated to the application and optimization of new methods, and it shows how quantitative real-time PCR, flow cytometry and molecular methods in different combinations can be used as powerful tools for the study of plankton ecology.

Baltic archipelago areas have high nature values despite being polluted from various antrophogenic activities within the Baltic Sea catchment area and from long-range transport of airborne substances. The discovery of environmental problems in the Baltic Sea in the 1960s led to countermeasures that gradually gave results in reducing the toxic pollution, e.g. from PCBs. Today, much of the environmental management is focused on reducing the effects of eutrophication. There is a demand from society on science to develop strategies that can direct remedial actions so that the cost-effectiveness is maximised. This work focuses on how mass-balance models can be used to understand how coastal ecosystems are controlled by abiotic processes and to predict the response to changes in loading of different substances. Advection, sedimentation and burial are examples of general transport processes that are regulated by morphometrical characteristics, e.g. size, form, effective fetch and topographical openness. This is why different coastal areas have different sensitivity to loading of pollutants. A comparison of six phosphorus and chlorophyll models of different complexity showed that the model performance was not improved with more state variables of total phosphorus (TP) than two water and two sediment compartments. Modelling chlorophyll as a separate state variable did not improve the results for individual values compared to a simple regression against total phosphorus in surface water. Field investigations of the phosphorus content in accumulation sediments along the coast of Svealand showed a distribution pattern that probably is related to differences in the redox status. The average content of mobile phosphorus was much higher than previously found in offshore Baltic sediments indicating that sediments may play an important role for the phosphorus turnover in Baltic archipelago areas. A one-year field study to measure the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in water, sediments and fish during different seasons was carried out in Kallrigafjärden Bay. The collected data set was used to test a mass-balance model for PCCD/F-turnover. It was possible to reproduce the concentrations of different PCDD/F-congeners with high accuracy using a general model approach, including one water compartment and two sediment compartments, indicating that the applied model has the necessary qualifications for successful predictions of PCDD/F-turnover in Baltic coastal areas. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 736

129I is a radioactive isotope (T1/2= 15.7 million years) produced through natural and anthropogenic pathways, but the anthropogenic production is presently dominating the Earth’s surface environments. Sparse data from previous investigations in the Baltic Sea clearly indicated the occurrence of 129I at levels 3-4 orders higher than natural pre-atomic era (before 1940) without comprehensive evaluation of distribution and inventory. In this thesis extensive data on the distribution and inventory of iodine isotopes, 129I and 127I, and their species in waters of the Baltic Sea, Kattegat and Skagerrak are presented and used for estimation of water masses exchange and impact on the environment.  To fulfill these objectives seawater samples were collected in August 2006 and April 2007 in the Baltic Proper, Kattegat and Skagerrak as well as in December 2009 in the Bothnian Sea. After elaborative chemical separation of total iodine and iodine species, the analysis was performed using ICP-MS for 127I and AMS for 129I. The results reveal considerable differences in 129I concentration in terms of spatial and temporal variability and expose relatively high concentrations in the deep waters. Inventory estimates show higher amounts of 129I in August 2006 (24.2 ±15.4 kg) than in April 2007 (14.4± 8.3 kg) within the southern and central Baltic Proper, whereas almost a constant inventory is found in the Kattegat Basin. Relatively high 127I-/127IO3- and 129I-/129IO3- values in water of the Baltic Proper suggest effective reduction of iodate at a maximum rate of  8×10-7 (127IO3-) and 6×10-14 (129IO3-) (g/m3.day). The combination of 129I and 127I as tracers of water circulation in the Baltic Sea suggest that upwelling deep basinal water occurs into the surface along the Gotland deep and intrusion of North Atlantic water into southern Baltic. Furthermore, 129I-based model inventory reveals inflow of 330 km3/y (230-450 km3/y) water from the Kattegat into the Baltic Proper. Water exchange between the Baltic Proper and the Bothnian Sea and vice versa is estimated at 980 km3/y (600-1400 km3/y) and 1180 km3/y (780-1600 km3/y) respectively. Finally, an environmental assessment of radioactivity associated with 129I burden in the Baltic Sea region is discussed.

The European Commission manages fish stocks by applying a fishing mortality based on the maximum sustainable yield concept. So far most Baltic Sea fishing maximum sustainable yieldmodels have focused on one species at a time. The few existing multi-species models have assumed that a species’ maturity and growth is dependent on the availability of food. Our two-species models make it possible to investigate if there is a conflict between fishing maximum sustainable yield for cod and herring in the Baltic Sea. This two-species model of cod, as a predator and herring as prey, takes into account environmental drivers on cod and herring recruitment. Reproductive volume together with year-growth, (a year specific effect on growth of external variables like food availability) and predation by grey seals was included in the cod model. The herring model was dependent on cod spawning stock biomass and year-growth. The result shows that the reproductive volume is the main factor that affects the maximum sustainable yield for cod. The spawning stock biomass at maximum sustainable yield is more sensitive to reproductive volume than year-growth. When predation from seals is added in mortality and high environmental factors occurs the spawning stock biomass would be 50% compared to the spawning stock biomass at high environmental effects without seal predation. Four simulations of high cod spawning stock biomass were devastating for the herring population that was eradicated with high predation pressure. The herring maximum sustainable yield depends on the amount of cod spawning stack biomass i.e. the effect of high or low reproductive volume. Two analyses were made on a current environmental state for both species. The first analysis had a natural mortality of 0.2 for cod, which gave an fishing mortality of 0.20 and maximum sustainable yield of 410 000 tons. The herring had a fishing mortality of 0.03 and maximum sustainable yield of 11 000 tons. The second simulation included seal predation in cod mortality which decreased the cod maximum sustainable yield by 98% at a fishing mortality of 0.02, which gave a fishing mortality of 0.19 and maximum sustainable yield of 275 000 tons for herring. This gives a 25 times increase of herring maximum sustainable yield compared to the result without predation on cod. The cod population dynamics is vulnerable to environmental changes and to secure a healthy and productive cod population the target fishing mortality should be kept in phase with current reproductive volume. / Europeiska kommissionen förvaltar fiskbestånden genom att tillämpa fiskekvoter baserat på konceptet maximalt hållbart uttag. Hittills har de flesta maximalt hållbara fiske-fångst modeller för Östersjön fokuserat på en art i taget. De få befintliga fler-arts-modeller har antagit att en arts mognad och tillväxt är beroende av tillgången på föda. Vår två-arts-modell gör det möjligt att undersöka om det finns en konflikt mellan maximal hållbar fiske-fångst på torsk och sill i Östersjön. Denna två-arts-modell med torsk som ett rovdjur och sill som byte, tar hänsyn till miljön som drivkraft på deras rekrytering. I torskmodellen ingick reproduktiv volym tillsammans med årlig tillväxt (ett års specifika effekt på tillväxten beroende av externa variabler som tillgången till föda) och predation av gråsäl. Sill-modellen var beroende av årlig tillväxt och lekbeståndets biomassa hos torsk. Resultaten visar att den viktigaste faktorn som påverkar maximalt hållbart uttag för torsk är reproduktiv volym. Lekbeståndets biomassa vid maximalt hållbart uttag är mer känsligt för förändringar i reproduktiv volym än årlig tillväxt. När predation från säl tillsätts och höga gynnsamma miljöfaktorer råder är lekbeståndets biomassa 50 % jämfört med lekbeståndets biomassa vid höga gynnsamma miljöeffekter utan säl predation. Fyra simuleringar gav hög lekbestånds biomassa för torsk vilket var förödande för sillpopulationen som utrotades pga. högt predationstryck. Sillens maximala hållbara uttag beror på mängden lekbestånds biomassa hos torsk, d.v.s. effekten av hög eller låg reproduktiv volym. Två analyser gjordes på nuvarande miljömässiga nivåer för båda arterna. Den första analysen hade en naturlig dödlighet på 0,2 för torsk, vilket gav en fiske-mortalitet på 0,20 och maximalt hållbart uttag på 410 000 ton. Sillen hade en fiske-mortalitet på 0,03 och maximalt hållbart uttag på 11 000 ton. I den andra simuleringen ingår sälpredation på torsk vilket minskade torskens maximala hållbara uttag med 98 % vid en fiske-mortalitet på 0,02, vilket gav en fiske-mortalitet på 0,19 och maximalt hållbart uttag på 275 000 ton för sill. Detta ger en ökning av maximalt hållbart uttag för sill 25 gånger jämfört med resultatet utan predation på torsk. Torskens populationsdynamik är sårbar för miljöförändringar och för att säkra ett sunt och produktivt torskbestånd bör fiskemortaliteten hållas i fas med nuvarande reproduktiva volym.

This paper proposes the notion that words mirror ideas, perspectives and worldviews. Etymologies and meanings of general words for ‘islands’ in a number of languagesin North and West Europe are then discussed. Here, islands are shown to be etymologicallyconstituted by the interplay between land and water, and which of these two is emphasizedvaries. In the third section, a number of Swedish island words are surveyed, in an attemptto illuminate the principle of linguistic relativity. Finally, the implications of these findingsfor island studies are discussed.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 4 uppsatser.

Drawing on a theoretical framework based on securitization and threat construction, the attempt in this study was to broaden the understanding of how the perception of a Russian threat in the Baltic Sea is influencing Swedish defence and security policy. The method used was based on Bacchis WPR-approach. Three questions were asked at the beginning of this study, regardning how Russia is viewed in Sweden, how the representation of Russia has changed from the war in Georgia in 2008 until 2018, as well as how Sweden is to strengthen it's defence capacity, nationally and through cooperation, to tacle the Russian threat. Four key aspects of Russian behaviour that is considered threatening were identified. Russia is viewed as a country with power ambitions and expansionist tendencies; characterised as tactically unpredictable; looked upon as a risk calculating actor; and considered misstrusting in its views of the West. The perception of Russia is complex which creates difficulties regarding how the threat is to be met. Policy makers have urged the strengthening of Swedish national defence capacity to create a conflict threshold in the region. To further strengthen this threshold, the bilateral defence cooperation with Finland has deepened. In addition, the question of military non-alignment has been raised in relation to a possible Swedish membership in Nato. The answer to whether or not Sweden should join depends on political affiliation. This underlines the theoretical assumptions; security and defence policy is not merely a response to an external circumstance, but rather the result of an interplay between circumstance and actor.