Eutrophication of seas, particularly near the coasts, is a topic of high current concern. Itleads to increased primary production and a higher frequency of algal blooms. The enhancedprimary production also increases the turbidity of the water, making it harder for ecologicallyimportant benthic macro algae, e.g. seaweed, to colonize bottoms on deeper waters. EU directives, as well as national law, demand decreases in nutrients, e.g. nitrogen, reachingthe sea. Another approach to decreasing the amount of nutrients in the sea could be musselfarming. Mussel farming is an established, albeit small, industry on the Swedish west coast. The useof mussels to remove nitrogen, however, is a more recent application. Lysekil municipalityhas been granted exemption from improving the nitrogen removal in Långevik waste watertreatment plant. Instead, mussel farms are used to remove nitrogen, which was estimated to bea less costly solution. This thesis investigates the advantages in money and energy in using mussel farming. Theuse of a mussel farm to remove nitrogen from sea water is compared with removing nitrogenin a WWTP. In addition, the production of mussel fertilizer, through a composting process, iscompared with producing a corresponding amount of artificial fertilizers. The results show that mussel farms are neither more economic nor energy efficient inremoving nitrogen and producing fertilizer than the conventional alternatives examined Mussel fertilizer, however, is not the most lucrative product that the mussels from the farmcan give. Alternatives, such as fodder or human consumption, are discussed in the report. Furthermore, the mussel fertilizer qualifies as organic fertilizer. A comparison with otherorganic fertilizers could prove mussels more economic or energy efficient, but such acomparison is out of the scope for this thesis. Finally, some data, e.g. the energy demand for nitrogen removal in the WWTP, were roughestimations. More research and investigations are needed in order to achieve more accurateconclusions. / Eutrofiering i haven, speciellt kustnära vatten, är ett högaktuellt problem. Det leder till ökadprimärproduktion och frekvens av algblomningar. Den förhöjda primärproduktionen lederäven till ökad turbiditet, något som försvårar för ekologiskt viktiga bentiska arter, t.ex. sjögräs(ålgräs), att kolonisera bottnar på djupare vatten. Så väl EU-direktiv som nationell lagstiftning kräver en minskning i näringsämnen, bl.a.kväve, som når havet. Ett verktyg för att klara av dessa minskningar kan vara musselodlingar. Musselodling är en etablerad, men liten, industri på den svenska västkusten. Musslor som enkväveavskiljningsmetod är däremot en ny tillämpning. Lysekil kommun har fått undantag frånatt bygga ut kvävereningen i Långevik vattenreningsverk. I stället används musselodlingar föratt ta bort kväve, vilket ansågs vara en billigare metod. Detta examensarbete undersöker fördelarna i pengar och energi i att användamusselodlingar för att få bort kväve från havsvatten, jämfört med att avskilja kväve ivattenreningsverk. Dessutom jämförs produktionen av musselgödning, genom att komposteramusslor från musselodlingen, med att producera motsvarande mängder med konstgödsel. Resultaten visar att musselodlingar vare sig är billigare eller mer energieffektiva än dekonventionella alternativen för att ta bort kväve och producera gödsel. Musselgödning är däremot inte den mest lönsamma produkt som musslorna frånmusselodlingen kan ge. Alternativ som foder och mänsklig konsumption diskuteras i rapporten. Vidare kan musselgödning godkännas som KRAV-gödsel. I en jämförelse mot andraKRAV-gödsel kan musselgödning visa sig mer ekonomisk eller energieffektiv, men en sådan jämförelse ligger utanför detta arbetes tidsram. Slutligen var vissa data grova uppskattningar, t.ex. energiåtgången för kväveavskiljning i vattenreningsverk. Mer forskning och undersökningar behövs för att nå mer tillförlitligaslutsatser. / www.ima.kth.se

The current explanation for the absence, or low abundance, of filter-feeding invertebrates from some rocky shores is that because of local variation in nearshore oceanographic conditions, larvae do not arrive in sufficient numbers to establish populations. One putative consequence of this is that macroalgae are able to establish dominance in areas where filter-feeders (especially mussels) do not recruit well. While macroalgae have been transplanted to mussel-dominated shores with varying success, the survival, growth and reproduction of transplanted mussels has not been tested in areas dominated by macroalgae. To determine specifically what tips the balance between shores dominated by filter-feeding invertebrates and those dominated by macroalgae, I monitored the recruitment of intertidal mussels at four sites on the Kaikoura coast: two with mussels present and two algal-dominated. No significant differences in mussel recruitment rates were found between habitats and recruitment intensity at all sites was found to be very low. Recruitment limitation is not the reason for the absence of mussels from algal dominated shores but some form of limitation does occur to reduce the number of arriving mussels. Predation effects were examined by transplanting juvenile mussels into caged, uncaged and control treatments. No significant differences in predation rates between habitats were found and transplanted mussels in open cages at all sites were removed within 3 days. Mobile fish predators appeared to be the most likely cause of this intense predation. Growth of transplanted mussels into algal and mussel habitats was found to be significantly different. Mussels grew faster in mussel dominated habitats and after 6 months in algal dominated habitats, all mussels had died. The outcome of these experiments indicates that there is a close relationship between recruitment, survival and growth which tips the balance and allows the existence of mussel beds along the Kaikoura coastline.

Environmental genotoxicants/carcinogens in the aquatic environment induce complex detrimental impacts on aquatic organisms. Integrated approach is required to comprehensively assess such impacts in terms of animal and environmental health. Biomarkers at different levels of biological organisations, including clearance rates (at individual level), histopathological alterations (at tissue level), DNA strand breaks using comet assay (at cellular level) and transcriptional alterations of key genes determined by real-time quantitative PCR (at molecular level), were designed and applied to analyse the impacts in marine bivalve: Mytilus sp., a classic bio-indicator species for environmental health monitoring, following exposure to selected environmental contaminants (i.e. Benzo(α)Pyrene (B(α)P), C60 fullerene, and tritium). The performance of biomarkers changed in response to exposures with higher sensitivity for DNA strand breaks and transcriptional alterations of selected genes. In particular, genes representing 7 gene groups (tumour suppressor gene - p53, proto-oncogene - ras, cytochrome P450 family - cyp4y1, MAPKs family - jnk, Bcl-2 family - bax, MDM2 - mdm2 and RAD family - rad51) showed tissue- and chemical-specific expression profiles under selected experimental conditions. A comparison revealed similarity of interplay among these highly conserved genes with mammalian models, suggesting Mytilus sp. could be an ideal model for signalling research in the carcinogenesis process. To my knowledge, this is the first research to detect tissue specific transcriptional alteration of p53 and ras genes in the organism for the analysis of detrimental impacts induced by different environmental genotoxicant/carcinogen exposures. Furthermore, the study is also the first one to include genes which can interplay with each other to function in the regulation of DNA repair, apoptosis and cell cycle arrest in marine organisms. The results suggested that the applied integrated biomarker approach is a comprehensive and sensitive method to monitor environmental health and, marine bivalve Mytilus sp. is an ideal model organism for research on genotoxicant induced carcinogenesis and will shed light on the mechanisms of this complex process in higher organisms, including humans.

Anthropogenic activities are fundamentally altering the chemistry of the world’s oceans. Many of these modifications could have a significant impact on the health of marine organisms. Yet, despite being proposed as one of the most significant threats that marine ecosystems face, to date very little is known about the impact of anthropogenic climate change, and ocean acidification in particular, on host defence. The aims of this thesis are to investigate the impact of environmental stressors on the invertebrate immune response, providing empirical data on how anthropogenically induced stressors will impact the invertebrate immune system and how this will impact organism condition and subsequent physiological trade-offs. Exposure to reduced seawater pH and increased temperature significantly reduced the immune response in the blue mussel, Mytilus edulis. This reduction in immune response could indicate stress-induced immune dysfunction. However, the immune system protects an organism from infectious disease, ensuring survival, and should therefore be evaluated functionally rather than immunologically. By subsequently exposing mussels to a bacterial challenge this study demonstrated that an earlier study which measured a reduction in host defence represented a trade-off of immune system maintenance costs, with mussels maintaining a capacity to up-regulate immune defence when required. However, whilst this immune plasticity ensures mussels are able to survive a pathogen exposure, such a strategy appears to be physiologically costly. This cost is seen as a reduction in reproductive investment, an altered energy metabolism and an altered fatty acid composition in organisms exposed to low pH. Therefore the overarching picture that emerges is, without measuring physiological processes functionally, and in neglecting any physiological trade-offs, it is possible that many studies may misinterpret the complex physiological responses of marine organisms to ocean acidification.

Copper (Cu) is a heavy metal that is essential for life but toxic at high concentrations. This toxic effect is used on boats to prevent biofouling on boat hulls by painting the hulls with antifouling paint that contain high levels of Cu. The Cu is slowly diffused out in the water and accumulated by animals higher up in the food chain. In order to test the effects of marinas on Cu bioaccumulation in invertebrates, I sampled molluscs at seven marinas and seven shore sites on the Swedish west coast. Two molluscs with different feeding behaviours, one grazer, the periwinkle (Littorina littorea) and one filter feeder, the blue mussel (Mytilus edulis) were used as study organisms. Both species were sampled at each location within 50 m from each other. Body Cu concentration of both species was measured with a Flame Atomic Absorption Spectrometer (FAAS). Cu concentration of periwinkle soft body tissue was generally higher than in mussel soft body tissue. In addition, periwinkle tissue Cu concentration reacted strongly positively to the presence of marinas, whereas mussel tissue Cu concentrations did not. This shows that contamination from marinas affects the grazing periwinkle but not the filter feeding blue mussel. Thus, for biomonitoring purposes, grazers may be more suited as indicator organisms.

No description available.

Cyanobacteria produce a variety of secondary metabolites which possess amongst others antifungal, antibacterial, and antiviral properties. Being primary producers they are also a vital component within the food web. However, certain strains also produce toxic metabolites such as the hepatotoxins microcystin (MC) and nodularin (NOD). Their toxicity in combination with the increasing global occurrence has resulted in a drinking water guideline limit of 1 μg L-1 being issued by the World Health Organisation (WHO). However, these toxins are not only present in water, but can be accumulated by fish and shellfish. Currently, no regulations regarding cyanotoxin contaminated seafood has been established despite similar toxicity to routinely monitored marine toxins such as domoic acid (DA). To facilitate regular monitoring, a high performance liquid chromatography photo diode array (HPLC-PDA) analysis method for the detection of DA was optimised to enable the simultaneous detection of DA and nine cyanotoxins. This method was then utilised to determine cyanotoxin concentration in laboratory cyanobacteria strains. To assess the accumulation and depuration of cyanotoxins in the common blue mussel Mytilus edulis, three feeding trials were performed. During these, mussels were exposed to two cyanobacteria strains, Nodularia spumigena KAC66, Microcystis aeruginosa PCC 7813, both individually and simultaneously. A rapid dose dependent accumulation of cyanotoxins was observed with maximum concentration of 3.4 -17 μg g-1 ww accumulated by M. edulis, which was followed by a much slower depuration observed. During the final feeding trial, with N. spumigena KAC 66 and M. aeruginosa PCC7813, cyanotoxins were still detectable following 27 days of depuration. Mortality in all studies was 7% or less indicating that most mussels were unaffected by the maximum dose of 480 μg L-1 NOD (feeding study 1), 390 μg L-1 MC (feeding study 2), or 130 μg L-1 total cyanotoxins (feeding trial 3), respectively. Mortality in negative control tanks was lower throughout all three feeding trials ( < 1 - 2.6%). Consumption of a typical portion size (20 mussels) would result in ingestion of cyanotoxins at levels significantly higher than the WHO recommended tolerable daily intake (TDI) of 2.4 μg NOD and/or MCs for a 60 kg adult. This value was exceeded not only during the exposure period (maximum levels 270 - 1370 μg cyanotoxins per 20 mussels), but also at the end of the depuration period 39-600 μg cyanotoxins per 20 mussels. These results illustrated that cyanotoxin monitoring of seafood should be considered not only during, but also following bloom events. In an attempt to investigate the cyanotoxin budget of the experimental system, not only mussels, but cyanobacteria cultures, the tank water, and the mussel faeces were also analysed for their cyanotoxin content. Results showed that large quantities of MCs and NOD were unaccounted for during all exposure trials. The combined effect of cyanotoxin metabolism in M. edulis, biotic and/or abiotic degradation, protein binding, and losses during the extraction and analysis were thought to have contributed to the unaccounted cyanotoxin fraction. Mussel flesh was analysed for the presence of glutathione or cysteine conjugates, however, there was no evidence of their occurrence in the samples tested. Due to these discrepancies in the toxin budget of the system, the introduction of correction factors for the analysis of cyanotoxins in M. edulis was suggested in order to protect the general public.

Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 154-174.

Current protection of the marine environment from radiation is based largely on measuring, estimating and modelling accumulation and impact(s) of radionuclides in a few marine species. Using a relevant marine organism, this thesis focusses on investigating some poorly described phenomena that could cause deviations from predicted measurements. Paper I investigated the biological transformation of tritium (radioactive hydrogen) into an organic compound. The resulting organically bound tritium (OBT) showed increased accumulation in mussels, unique incorporation into a key biological molecule (DNA), extended persistence in tissues, and greater toxicity than the inorganic form. Paper II demonstrated significant disparity in OBT accumulation between functionally similar microalgae species and that OBT in algae is readily transferred to a consumer. Highly radioactive particles are a complex issue in radioecology due to their concentrated dose geometry, potentially inducing very different impacts in organisms, compared to external irradiation. Paper III developed a method to introduce radioactive particles that would facilitate their recovery, improve dose-calculation, and aid the measurement of toxicological endpoints. It also showed that such particles can be incorporated into mussel tissues, causing significant effects. In Paper IV, hypoxia – another major ecological hazard in the marine environment – was expected to reduce radiosensitivity. The minimal observable effect from radiation prevented identification of such an interaction, and indicates drawbacks in the (otherwise sensitive) endpoints used. It appears that stressors like hypoxia may be more of a health hazard to marine organisms than environmental levels of ionising radiation. By understanding such causes of variation in accumulation and impact, it is possible to improve risk assessment, providing more justification for regulations chosen and minimising conservatism in setting environmental standards. / <p>At the time of doctoral defense, the following papers were not published and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>

Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (February 17, 2010) Includes bibliographical references (50-54)