Browsing by Issue Date, starting with "2024-04-12"
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- Regulatory mechanism of bivalve shell biomineralization and its response to global climate changePublication . Peng, Maoxiao; Power, Deborah M.; Cardoso, João Carlos dos ReisBivalves are one of the most diverse animal groups in the ocean and are found everywhere on Earth. They provide important ecosystem services in the marine environment as they filter environmental waters but also contribute to the nutrient and carbon cycle and are a rich source of nutrients for humans and other animals. Aquaculture of marine bivalve is an economically important industry worldwide that is currently expanding and because bivalve production is environmental-friendly they can provide an alternative protein source to meet the growing demand for food by the growing world population. Bivalves are characterized by possessing two valves that form the shell that is secreted by the mantle which is essential for their survival since it protects them from the environment and predators but also serves as a store of minerals. How bivalves produce and maintain their shells has been the topic of many studies especially because this structure is considered to be highly sensitive to changes in the ocean environment as a consequence of climate change and environmental pollution compromising their existence and survival. However, the large biodiversity of bivalves, the limited number of species studied and the diversity of exuberant shells with different mineralized structures suggests that the mechanisms of shell formation and growth and their susceptibility to environmental stressors might be species-specific. The main objective of this thesis is to increase knowledge about bivalve shell biomineralization by exploring and comparing the molecular factors that regulate shell growth and maintenance and composition in two commercially important aquaculture species that occupy the same ecological niche but possess different shell morphologies the Pacific oyster (Magallana gigas) and the Mediterranean mussel (Mytilus galloprovincialis) using animal experimentation, and multi-omics analysis using available bivalve genomes and transcriptomes, biochemical and gene knock down approaches. The results of this thesis revealed that: 1) long non-coding RNAs (lncRNA) and non-matrix protein encoding genes are important factors in the regulation of shell matrix protein (SMP) and non-SMP genes that modify shell structure (Chapter 2), 2) shell growth in M. gigas and M. galloprovincialis is hampered by OA but the two animals respond differently and M. galloprovincialis employs a larger number of biomineralization genes and most likely invests more energy to maintain the shell (Chapter 3) and 3) there is a large diversity of CHS (Chitin-synthase) isoforms with a complex evolutionary history and that M. gigas and M. galloprovincialis (Chapter 4). The tissue distribution of CHS indicates a far more complex suite of actions than the production of part of the organic scaffold for calcium carbonate crystal deposition in the shell. Furthermore, CHS respond differently to OA implying plasticity in the response of chitin production and an involvement in modulating the production of the shell.
- Strategic environmental leverage of a sport tourism event: approaching the global challenge locallyPublication . Martins, Rute; Pereira, Elsa; Mascarenhas, MargaridaThe proactivity in the management of sport events is essential to maximise environmental benefits for the host communities through strategic leverage. Therefore, this study aimed to understand the process of strategic environmental leverage in an internationalnature-based non-mega event of sport tourism (Sintra PRO 2022 -stage of the IBC World Bodyboarding Tour) by means of action research. Data collection combined several methods and sources, namely, document research, nominal group sessions, field observation, and interviews conducted with organisers and partners of the event. Three actions, which synergistically linked the environmental values of community projects and the sport subculture, were implemented in order to focus stakeholders' attention on the environmental topics. The availability of local resources and the involvement of the network of local partners facilitated the implementation of environmental leverage. On the other hand, the lack of communication between those involved in the operationalisation and promotion of environmental leverage actions was a constraint in the process. This study highlights several implications for environmental leverage in sport events, as well as for the applicability of the environmental leverage model to promote strategic planning and the implementation of the resulting strategic environmental leverage actions in sport events.