Graduation Date
Spring 2018
Document Type
Thesis
Program
Master of Science degree with a major in Biology
Committee Chair Name
Dr. Paul Bourdeau
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Dr. Bengt Allen
Second Committee Member Affiliation
Community Member or Outside Professional
Third Committee Member Name
Dr. Eric Bjorkstedt
Third Committee Member Affiliation
HSU Faculty or Staff
Fourth Committee Member Name
Dr. Jeffrey Abell
Fourth Committee Member Affiliation
HSU Faculty or Staff
Fifth Committee Member Name
Dr. Joe Tyburczy
Fifth Committee Member Affiliation
HSU Faculty or Staff
Subject Categories
Biology
Abstract
Research shows ocean acidification (OA) can have largely negative impacts on marine organisms and ecosystems. Prior laboratory studies show that shelled marine invertebrates (e.g., molluscs) exhibit reduced growth rates and weaker shells when experiencing OA-related stress. However, populations of the critical intertidal mussel species, Mytilus californianus, which experience naturally acidic water due to upwelling in certain parts of Northern California have been observed to have relatively stronger and thicker shells and higher growth rates than those that experience less frequent exposure to upwelling. To address the discrepancies between negative effects of OA exposure in the laboratory and seemingly positive effects off OA exposure in the field we collected juvenile mussels from four separate locations on the northern California coast that vary in exposure to upwelling-driven OA and raised them under ambient, constantly acidified, or intermittently acidified seawater conditions. Half of the mussels in each of the experimental treatments were given access to either ambient or elevated food concentrations. Although higher food availability increased shell and overall mussel growth, variation in mussel life-history traits among locations appears to be driven primarily by inherent differences (i.e. genetics or epigenetics). In particular, overall growth, soft tissue mass, and shell dissolution in mussels were associated with source-specific upwelling strength while adductor muscle mass along with shell growth and strength of mussels were associated with source-specific levels of predation risk. Oxygen consumption of mussels did not significantly vary among food, pH or source location treatments, suggesting that differences in growth rates were not due to differences in differences in metabolic or energetic efficiencies between individuals. Although not statistically significant, mussels from areas of high crab predation risk tended to survive crab attacks in the lab better than mussels from other areas. My data suggests that the adaptive potential of M. californianus to respond to future OA conditions is dependent on local environmental factors such as upwelling strength, food availability, and predation risk. My study addresses a significant gap in our understanding of the mechanism behind conflicting observations of increased growth in the field associated with low pH and previous laboratory results, demonstrating the importance of environmental context in shaping the organismal response to current and future OA conditions.
Citation Style
APA
Recommended Citation
Man, Tharadet Daniel, "The interactive effects of ocean acidification, food availability, and source location on the growth and physiology of the California mussel" (2018). Cal Poly Humboldt theses and projects. 139.
https://digitalcommons.humboldt.edu/etd/139