Heterotrophic microorganisms are important for the flow of carbon and nutrients in the sea. Bacteria, nanoflagellates and ciliates are relevant components of the pelagic food web. In order to be able to predict the outcome of e.g. eutrophication or climate change we need to know how the different components of the pelagic food web are regulated. With the focus on the northern Baltic Sea food web, this thesis deals with limitation and control of heterotrophic protists, the effect of resource heterogeneity on food web efficiency and diversity of nanoflagellates. In-situ microcosm experiments showed that the net growth of heterotrophic flagellates were resource limited throughout the year. Field data confirmed that the abundance of flagellates was bottom-up controlled. Furthermore, field data also showed that the annual average biomass of protists, flagellates and ciliates increased with primary productivity. On a smaller seasonal scale temperature and bacterial biomass were able to explain most of the variation in flagellate biovolume. The temporal variation in ciliate biovolume could not be explained by any bottom-up factors like bacterial biomass, flagellate biomass or chlorophyll a. This and an in-situ microcosm experiment implied that the seasonal dynamics of ciliates were more regulated by predators like mesozooplankton. The food web efficiency i.e. how much of production at the resource level is converted to production at the top trophic level, may be affected by specific size or type of resource. Indoor mesocosms revealed that the food web efficiency was 11 times lower when heterotrophic bacteria dominated basal production instead of nano- and micro-sized phytoplankton. This was due to a lengthening of the food web when pico-sized bacteria constituted the main resource. The PCR-DGGE molecular biological method was used to study the diversity of heterotrophic or mixotrophic chrysomonads. The focus was set on chrysomonads due to their relatively large contribution to the nanoflagellate community. Group-specific PCR primers were optimized for the target group. A field survey in the northern Baltic Sea showed that a handful of chrysomonad sequences were present throughout the year. Significantly more chrysomonads were recorded in the basin with higher primary productive and salinity. In total 15-16 different chrysomonad sequences were recorded. Most of them matched uncultured chrysomonad clones.

Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą] / The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text]

The evaluation of the passive admixture transfer in the marine environment is very significant from the point of view of environmental protection. A particular attention is devoted to the Baltic Sea ecological state, which is strongly influenced by the peculiarities of the sea bottom, weak connection with the World Ocean, climatic and hydrometeorological conditions. During the recent decades, the tendency of increment of the amount of anthropogenic pollutants is observed. The development of nuclear energetics and technology inevitably causes the spread of radionuclides of technical origin in the marine environment. The major attention is paid to the investigation of the radionuclide 137Cs distribution, since the investigations show the high values of the volumetric activity of this radionuclide to be present in the sea water thus far. Besides that, 137Cs radionuclide can be used as a tracer in investigations of the migration of other passive admixtures in the Baltic Sea water. Quite a number of scientists research the problems related with the amounts of the radionuclide of technical origin, their spread and impact on the marine environment. However, the works considering a problem of the variations of volumetric activity of radionuclides and their transfer in the coastal waters of the Baltic Sea practically are not encountered. Considering that, the volumetric activity of radionuclide 137Cs in the coastal surface waters of the Lithuanian territorial zone of the Baltic Sea... [to full text] / Pasyviųjų priemaišų jūrinėje aplinkoje įvertinimas ypač svarbus gamtosauginiu aspektu. Ypatingas dėmesys skiriamas Baltijos jūros ekologinei būklei, kurią lemia jūros dubens ypatybės, silpnas ryšys su Pasauliniu vandenynu, klimatinės ir hidrometeorologinės sąlygos. Pastaraisiais dešimtmečiais jūros baseine didėja antropogeninės kilmės teršalų kiekis. Branduolinės fizikos ir technikos plėtra neišvengiamai sukelia technogeninės kilmės radionuklidų patekimą į jūrinę aplinką. Daug dėmesio skiriama 137Cs radionuklidui, nes iki šiol jūros vandens tyrimai rodo aukštas šio radionuklido tūrinio aktyvumo reikšmes. Be to, 137Cs radionuklidas geras indikatorius, tiriant kitų pasyviųjų priemaišų migraciją Baltijos jūros vandenyje. Daug mokslininkų nagrinėja problemas, susijusias su technogeninės kilmės radionuklidų kiekiais, jų sklaida ir poveikiu jūrinei aplinkai. Tačiau darbų, kuriuose būtų nagrinėjama radionuklidų tūrinių aktyvumų pokyčių bei pernašos Baltijos jūros priekrantės vandenyje problema, praktiškai nėra. Atsižvelgiant į tai, šiame darbe nustatytas 137Cs radionuklido tūrinis aktyvumas Baltijos jūros Lietuvos priekrantės paviršiniame vandenyje bei įvertinti hidrometeorologiniai parametrai. 137Cs radionuklido tūrinis aktyvumas Baltijos jūros vandenyje nėra pastovus, todėl aktualu parinkti tinkamus nustatymo metodus ir vertinti jo pokyčių tendencijas. Įvertinus radiocezio tūrinio aktyvumo pokyčius priekrantės vandenyje, galima modeliuoti ir prognozuoti taršos šaltinio atsiradimo... [toliau žr. visą tekstą]

Surface elevation is likely the most fundamental property of our planet. In contrast to land topography, bathymetry, its underwater equivalent, remains uncertain in many parts of the World ocean. Bathymetry is relevant for a wide range of research topics and for a variety of societal needs. Examples, where knowing the exact water depth or the morphology of the seafloor is vital include marine geology, physical oceanography, the propagation of tsunamis and documenting marine habitats. Decisions made at administrative level based on bathymetric data include safety of maritime navigation, spatial planning along the coast, environmental protection and the exploration of the marine resources. This thesis covers different aspects of ocean mapping from the collection of echo sounding data to the application of Digital Bathymetric Models (DBMs) in Quaternary marine geology and physical oceanography. Methods related to DBM compilation are developed, namely a flexible handling and storage solution for heterogeneous sounding data and a method for the interpolation of such data onto a regular lattice. The use of bathymetric data is analyzed in detail for the Baltic Sea. With the wide range of applications found, the needs of the users are varying. However, most applications would benefit from better depth data than what is presently available. Based on glaciogenic landforms found in the Arctic Ocean seafloor morphology, a possible scenario for Quaternary Arctic Ocean glaciation is developed. Our findings suggest large ice shelves around parts of the Arctic Ocean during Marine Isotope Stage 6, 130–200 ka. Steered by bathymetry, deep water from the Amerasian Basin of the Arctic Ocean flows over the central Lomonosov Ridge into the Eurasian Basin. This water mass is traced on its continuing way towards Greenland and the Fram Strait. At the Morris Jesup Rise, bathymetry plays an important role in the partial re-circulation of the water into the Amerasian Basin. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Submitted.</p>

The Lithuanian coastal area represents a specific region of great economic and rcreational importance. This research has been focused on a few tens of kilometres of the wide continental coastal sector, the northern parts of the Curonian Spit and the Curonian Lagoonal area. The geological material and results of absolute dating collected from numerous sediment samples have served as the basis for the essential specification of the boundaries, age, genesis and palaeo-sedimentation conditions at different Baltic Sea development stages. / Lietuvos pajūrio geologinės sandaros pažinimas, jo geologinės raidos žinojimas, čia vykstančių geologinių procesų suvokimas neabejotinai buvo, yra ir bus ypač aktualūs. Tyrimų objektas apėmė kelių dešimčių kilometrų pločio Baltijos jūros pakrantės ruožą žemyniniame krante, Lietuvai priklausančias šiaurines Kuršių nerijos ir Kuršių marių akvatorijos dalis. Absoliutaus datavimo metodų taikymas nuosėdų ir moliuskų liekanų amžiui nustatyti, iškastinių moliuskų liekanų apibūdinimas, nauji paleobotaninių tyrimų rezultatai bei kita gausi geologinė informacija leido patikslinti Baltijos paleobaseinų vandens lygio (kranto linijos) kaitą vėlyvajame ledynmetyje ir holocene, sudaryti seriją paleogeografinių rekonstrukcijų – kartoschemų skirtingų Baltijos jūros raidos stadijų baseinams.

During summer, the Baltic Sea is subjected to the world’s largest cyanobacterial blooms. These blooms are linked to eutrophication and raise many questions concerning their effects on the ecosystem. To understand their impacts on the food web dynamics, it is essential to assess growth responses of grazers to these cyanobacteria. In the northern Baltic proper, copepods are the most important herbivores providing an essential link between the primary producers and higher trophic levels. In this Thesis, Papers I &amp; II evaluate methods to estimate copepod growth in response to feeding conditions in situ. The most conspicuous diazotrophic filamentous cyanobacterium in the Baltic Sea is Nodularia spumigena, a producer of nodularin which is highly toxic to vertebrates, yet its ecological role is largely unknown. In Paper III, reciprocal interactions between cyanobacteria, sympatric algae and copepods are studied. The results suggest that nodularin is likely involved in allelopathic interactions, but it is not an inducible defense against grazers. Furthermore, the results of Papers IV &amp; V, indicate that natural assemblages of N. spumigena and Anabaena spp. may support copepod reproduction and that total diazotrophic filamentous cyanobacteria appear to provide a beneficial feeding environment for the feeding stages of copepod nauplii, most probably by stimulating the microbial communities that nauplii feed upon. Since cyanobacterial blooms are projected to increase due to global climate change, the combined effects of toxic cyanobacteria, ocean acidification and global warming predicted for year 2100 are further investigated on copepods in Paper IV. Taken together, these studies indicate that filamentous diazotrophic cyanobacteria contribute to sustaining secondary productivity and have potential implications of management practices with respect to combating eutrophication, global climate change and sustaining fish feeding conditions. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.</p>

This thesis focuses on toxicity and occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in Baltic Sea biota. The aims were to assess OH-PBDEs potency for disruption of oxidative phosphorylation (OXPHOS) and determine their and related compounds exposure in Baltic blue mussel, herring and long-tailed duck. A method for analysis of OH-PBDEs in herring and long-tailed duck plasma was also evaluated. Relevant OH-PBDEs were tested in vitro for OXPHOS disruption, using a classic rat mitochondrial respiration assay and a cell mitochondrial membrane potential assay. All compounds were found to disrupt OXPHOS either by protonophoric uncoupling and/or via inhibition of the electron transport chain. 6-OH-BDE47 and 6-OH-BDE85, were identified as particularly potent OXPHOS disruptors. Strong synergism was observed when OH-PBDEs were tested as a mixture corresponding to what is present in Baltic blue mussels. Baltic blue mussel is main feed for several species of mussel feeding sea ducks which have decreased dramatically in numbers. To assess long-tailed ducks exposure to brominated substances, liver tissue from long-tailed ducks wintering in the Baltic Sea and blue mussels were analysed. The result confirms that long-tailed duck are exposed to OH-PBDEs via their diet. However, low concentrations were found in the duck livers, which suggest low retention of these compounds despite daily intake. How the nutritional value of blue mussels as feed for sea ducks are affected by OH-PBDE exposure still needs further studies. Other species of sea ducks foraging on Baltic blue mussels during summer months can also be more exposed due to seasonal variation in primary production. Herring sampled in the Baltic Proper and Bothnian Sea, were found to contain OH-PBDEs and high levels of their methylated counterpart, MeO-PBDEs. As demethylation of MeO-PBDEs is known to occur in fish, MeO-PBDEs may pose as additional source for more toxic OH-PBDEs in herring and their roe. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.</p>

The purpose of this study is to examine how Viking Line, Tallink Silja and Birka Cruises work with economic and environmental sustainability, and also to see how they work with new environmental legislations. In 2015 a new environmental legislation will be introduced, by the name Sulphur directive. The Sulphur directive entails a reduction in Sulphur dioxide emissions from ships where the emissions cannot exceed 0,1 percent. There are three alternatives to achieve the new environmental legislation, the use of Marine Gas Oil, LNG or scrubbers. All three alternatives will lead to increasing costs for the shipping industry. The three companies exerts its shipping traffic in the Baltic Sea, a sea that is highly sensitive to external impacts. In the study qualitative methods were used, three personal interviews and five telephone interviews. Five theories were used to understand how the companies work, their estimations and their decisions: Strategic Tourism Planning Process, the Triple Bottom Line, the COSO model, The Decision-making Process and Responsible Cruise Tourism. The results of the study show that all three companies are facing an uncertain economic sustainable future and the deciding factors will be technological development, fuel prices and competitiveness.

During the Late Bronze Age, the number of metal objects in the Baltic Sea region increased tremendously.  Mobility and interaction in this northern inland sea intensified. This occurred in a period of prehistory when the ship was the predominant symbol in southern Scandinavia. The ship can be found in rock carvings, on bronze objects and by way of erected stone monuments: stone ship settings. These stone ships are mainly to be found in the Baltic Sea region, with a marked concentration on Gotland. The stone ship settings and their landscape context are the focus of this dissertation. The objective is to clarify whether it is possible to find evidence of social groupings of people in the Nordic Late Bronze Age (1100-500 BC), by focusing on the stone ship monument, adopting a maritime approach. These people might have been part of a maritime institution specializing in trade and long distance journeys during this period, thus achieving a more advanced maritime way of life in the Baltic Sea. Are the ship settings an expression of these specific groups of people, who utilized their practices to position and articulate themselves in the landscape? If such maritime institutions can in fact be traced, there must also be uniformly structured locations for these groups of people to meet in, some kind of antecedents of harbours. By taking an inland sea, the Baltic Sea, as a geographical demarcation, a different perspective of prehistory is attained. The area in the Late Bronze Age and earliest Iron Age (950/900-200 BC) differed from the Nordic Bronze Age sphere. The communities around the Baltic Sea, through the establishment and sharing of mutual interests, seem to have reached a certain degree of consensus. This concordance might well be largely explained by the complex dependency on metal. Such a manifestation would not have been possible without an infrastructure or network, in this case a maritime one. This is something which has previously been overlooked in discussions on the Bronze Age in the Baltic Sea.

Benthic diatoms are valuable tools for biological monitoring and paleo-ecological reconstruction of past environmental conditions. This thesis aims at describing size-related properties of benthic diatoms and suggests that data assessment for community analysis can be improved by considering the importance of scale. It investigates which environmental factors structure epilithic diatom communities on the coast of the Gulf of Bothnia and identifies environmental factors correlated with phytobenthic biomass. It also contributes to the floristic knowledge of the Baltic Sea. Diatom species show large variation in size. The responses of large species (≥1000 μm3) in diatom communities to environmental factors are underestimated if solely measured as relative abundance, as is the common practice. However, relative abundance gives the best gradient resolution, as compared to surface area and biovolume, if species are counted separately in two biovolume classes. Small and large species in the same community may respond differently to the same environmental factors. To assess the principal environmental factors structuring diatom communities in the Gulf of Bothnia, 270 quantitative samples were collected from submerged stones. Sampling was carried out in spring in four areas of the Bothnian Bay, characterized by a stable north-south salinity gradient (0.4-3.3 psu), and in three areas of the Bothnian Sea which has a rather uniform salinity of ca. 5 psu. Canonical correspondence analysis (CCA) identified salinity and exposure to wave action as the principal factors structuring the diatom communities of the Bothnian Bay, whereas exposure to wave action was the principal factor in the Bothnian Sea. Measurements of relative ignition loss suggested that the cover of macroalgae, and thereby the higher abundance of epiphytic diatoms in the epilithic samples, was positively correlated with salinity in the Bothnian Bay and with water movement in the Bothnian Sea. Two new brackish water species are described, Navicula sjoersii S. Busse &amp; Snoeijs and N. bossvikensis S. Busse &amp; Snoeijs. The new species are compared with N. perminuta Grunow, a common brackish-water species.