Early life stages under ocean acidifcation : direct effects, parental influence, and adaptation

• Main Author: Lane, Ackley Charles
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Hong Kong (Pokfulam, Hong Kong) 2014
• Subjects: Ocean acidification - Environmental aspects; Balanus amphitrite; Tube worms; Ocean acidification
• Online Access: https://doi.org/10.5353/th_b5295507; http://hdl.handle.net/10722/216228

Anthropogenic carbon dioxide (CO2) emissions are forcing shifts in seawater carbonate chemistry. Having already caused the global average oceanic pH to drop from from 8.2 to 8.1, the trend is expected to continue in the coming centuries resulting in pH levels as low or lower than 7.4. This anthropogenically driven process is called ocean acidification, or OA. Reduced calcium carbonate due to OA threatens calcifiers as it is the building block used to calcify. For most species the process of OA will encompass many generations, and biological responses to OA will be shaped by evolutionary adaptation as the centuries progress. Adaptations to new environments can occur over tens of generations, and as such, evolution may provide an escape for some ostensibly vulnerable animals. So it is important to consider factors like multigenerational change and the potential for evolutionary adaptation when estimating the likelihood of success for any given species. In this thesis I present 1 study on the early life stages of the barnacle Balanus amphitrite and 4 studies on the early life stages of the calcifying tube worm Hydroides elegans and how they are affected by OA. By combining several controlled experiments that include quantitative genetics, fertilization kinetics, and multigenerational responses I present an in-depth, multi-perspective study of how an economically important biofouling species may fare as conditions shift over a relatively long period of time. (1) Larval survival, metamorphosis, and post-larvae calcification in response to multiple levels of seawater pH in both species. (2) Parental influence on fertilization success under future OA conditions in the broadcast spawning tube worm H. elegans. (3) Quantitative genetic analysis of multiple life history parameters, using offspring from a total of 48 mated pairs from 20 males and 13 females of H. elegans. (4) Influence of parental pH environment on performance of offspring in H. elegans. Major findings: (1) Observable effects of OA on the early life stages ...