Impacts of temperature on the molecular response of shellfish
Crandall, Grace Alan
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Climate change is causing the average global ocean temperature to increase. In the face of ocean warming, the majority of marine organisms will be impacted by this shift in thermal regimes. There will likely be some species, and some life stages of species, that will fare better than others. In this thesis, this concept is explored in two organisms. The first organism is the Pacific oyster (Crassostrea gigas), which is a valuable aquaculture product that also provides important ecosystem benefits. Larval Pacific oysters were grown in two temperature treatments, 23 ˚C and 29 ˚C, and proteomics was used to determine how temperature impacted the molecular response in the oysters. Processes related to growth and development were more abundant in oysters grown in 29˚C, while processes related to immune response were less abundant. The second organism is the Alaska Tanner crab (Chionoecetes bairdi), which is an important species in a commercial fishery. Specifically, I focused on southeast Alaska Tanner crab populations, which have a high prevalence of infection with an endoparasite called Hematodinium sp., and will have to face ocean warming. Tanner crab infected with Hematodinium sp. and uninfected crab were exposed to different temperature treatments - ambient (7.5˚C), elevated (10˚C), and decreased (4˚C). Transcriptomics was used to determine how temperature and infection with Hematodinium sp. influenced the molecular response in Tanner crab. Primary processes that were influenced by temperature were lipid storage, transcription, and morphogenesis. The genes associated with lipid storage and transcription have roles in immune function and clear expression pattern differences between temperature treatments. There were no distinct expression patterns of the genes associated with morphogenesis, and while it is a process that is less expected, it could be attributed to hemocyte morphology or type change in response to temperature or infection with Hematodinium sp. This thesis provides insight into how increasing ocean temperature will affect two important shellfish species, and the data associated with each project can be used for further research into shellfish physiology.
- Fisheries