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dc.contributor.authorVentura, Alexander
dc.date.accessioned2018-03-22T12:29:24Z
dc.date.available2018-03-22T12:29:24Z
dc.date.issued2018-03-22
dc.identifier.urihttp://hdl.handle.net/2077/55377
dc.description.abstractAnthropogenic CO2 emissions are leading to a gradual decrease in ocean pH and changes in seawater carbonate chemistry, a process known as ocean acidification (OA). Such changes in oceanic environmental conditions will have negative consequences for marine life and organisms producing calcium carbonate (CaCO3) structures are amongst the most vulnerable due to the additional costs associated with calcification and maintenance of calcified structures under more acidic conditions. As calcifying animals of particular commercial and ecological relevance, bivalve molluscs have frequently been the object of OA research. In this thesis, responses to changes in seawater acidity in commercially important bivalve species were investigated with the aim of understanding their adaptation potential to OA. As the main focus was on blue mussels, the first part of the thesis provided an introduction to blue musselspecies complex in Europe which is characterized by the three species Mytilus edulis, M. galloprovincialis and M. trossulus. An analysis of potential consequences of interspecies hybridization for the aquaculture industry, especially in the context of changing environmental conditions, was provided. Possible positive and negative effects of hybridization were identified, the complexity of the blue mussel-species complex was highlighted and the implications of hybridization for adaptation were discussed. In the following section of the thesis, responses of Mytilus edulis larvae from a Swedish west coast population to elevated seawater acidity were investigated. By exposing larvae to a wide range of seawater acidity, the physiological tolerance threshold for normal shell development was identified and corresponded to pHT (pH on the total scale) ~ 7.8 which approximates the lower extremes of the local pH range naturally experienced by the larvae. This suggests that these mussels are well adapted to their local environment characterized by considerable fluctuations in seawater pH. Additionally, this result allowed selecting an appropriate pH level (pHT ~ 7.5, beyond the present range of natural variability), representing a realistic OA scenario for the investigated population and driving enough biological response to further investigate adaptation potential. This was achieved by measuring genetic variance and heritability of larval fitness-related traits (i.e. size and malformation of shell) through a crossbreeding experimental design and quantitative genetic techniques. Results showed high trait heritability under elevated seawater acidity, an indication of the potential of adapting to OA. Finally, in order to understand what functions and genes may be targeted by natural selection in the context of OA, genes involved in the initial phases of shell formation in Pacific oyster (Crassostrea gigas) larvae were identified. With a genome available, the Pacific oyster was an ideal candidate for this task. The identified genes were attributed to four categories (metabolic genes, transmembrane proteins, shell matrix proteins and protease inhibitors) and are candidates for genes under selection in the context of an acidifying ocean. Altogether the results of this thesis contribute to a better understanding of bivalve adaptation potential to global changes and provide critical information for future work (e.g. investigation of allelespecific associated tolerance to changes in environmental parameters).sv
dc.language.isoengsv
dc.relation.haspartMichalek, K., Ventura, A. & Sanders, T., 2016. Mytilus hybridisation and impact on aquaculture: a minireview. Marine genomics 27, pp.3-7. ::doi::10.1016/j.margen.2016.04.008sv
dc.relation.haspartVentura, A., Schulz, S. & Dupont, S., 2016. Maintained larval growth in mussel larvae exposed to acidified under-saturated seawater. Scientific Reports 6, 23728. ::doi::10.1038/srep23728sv
dc.relation.haspartVentura, A., Wegner, K. M., Lazareff, H. & Dupont, S., (manuscript). Assessing adaptation potential to ocean acidification in blue mussels, Mytilus edulis, from the Swedish west coast.sv
dc.relation.haspartDe Wit, P., Durland, E., Ventura, A. & Langdon, C. J., 2018. Gene expression correlated with delay in shell formation in larval Pacific oysters (Crassostrea gigas) exposed to experimental ocean acidification provides insights into shell formation mechanisms. BMC Genomics 19:160. ::doi::10.1186/s12864-018-4519-ysv
dc.subjectocean acidificationsv
dc.subjectCO2sv
dc.subjectadaptationsv
dc.subjectlarvaesv
dc.subjectMytilus edulissv
dc.subjectCrassostrea gigassv
dc.titleBivalves in the face of ocean acidificationsv
dc.typeTextswe
dc.type.svepDoctoral thesiseng
dc.gup.mailalexander.ventura@bioenv.gu.sesv
dc.type.degreeDoctor of Philosophysv
dc.gup.originUniversity of Gothenburg. Faculty of Sciencesv
dc.gup.departmentDepartment of Biological and Environmental Sciences ; Institutionen för biologi och miljövetenskapsv
dc.gup.defenceplacekl. 13:00, hörsalen på Sven Lovén Centrum för Marin Infrastruktur, Kristineberg, institutionen för biologi och miljövetenskap, Kristineberg 566, 45178 Fiskebäckskilsv
dc.gup.defencedate2018-04-13
dc.gup.dissdb-fakultetMNF


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