Oyster larvae living in a multi-stressor world : vulnerabilities and potential for persistence

• Main Authors: Ko, Wai-kuen, 高慧娟
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Hong Kong (Pokfulam, Hong Kong) 2016
• Subjects: Effect of stress on - Oysters; Pacific; Ocean acidification; Pacific oyster
• Online Access: http://hdl.handle.net/10722/241408

Oysters are ecologically and economically important shellfish that have a complex life cycle involving several critical processes such as larval calcification and metamorphosis. Rising anthropogenic CO2 levels that cause ocean warming and ocean acidification are predicted to make coastal and surface oceans increasingly unsuitable for several calcifying marine invertebrates including oysters. Simultaneously, climate change-induced heavy precipitation in some parts of the world is expected to reduce ocean surface salinity. These multiple climate change stressors may not only reduce the calcification rate of marine calcifying species but also depress their metabolism. The impact of future climate change on the sensitive processes involved in the oyster’s complex life cycle, particularly metamorphosis, could be a bottleneck for population recruitment success. For example, in the U.S., oyster aquaculture is already failing to produce seeds due to climate change, providing evidence that oyster recruitment and populations may not be sustainable in future oceans. This is a stark warning to China, not only as a centre of oyster biodiversity, but also as the main producer of >80% of the world’s oysters. To avoid the possibility of future socioeconomic crisis and seafood insecurity, we need to assess how commercially important oyster species can tolerate future climate conditions. Therefore, the primary goal of this thesis is to understand how multiple climate change stressors, interactively and individually, can affect the economically and ecologically important edible oyster species, the Pacific oyster, at developmental, physiological, and molecular levels. The results demonstrated that long-term ocean acidification and exposure to multiple climate stressors had varying effects on the multiple life stages of larvae of the Chinese Pacific oyster. By analyzing multiple physical parameters (larval growth, respiration and feeding efficiency during metamorphosis, energy reserve for growth, metamorphosis success, early ...