Assessing the Role of pH and Elevated Temperature on Larval Development, Population Demographics and Connectivity of Three Coastal Mussel Species in San Diego

EPA Grant Number: FP916973
Title: Assessing the Role of pH and Elevated Temperature on Larval Development, Population Demographics and Connectivity of Three Coastal Mussel Species in San Diego
Investigators: Tanner, Christina A.
Institution: Scripps Institution of Oceanography
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2008 through August 31, 2011
RFA: STAR Graduate Fellowships (2008) RFA Text |  Recipients Lists
Research Category: Academic Fellowships


How will larval life stages persist in a high CO2 world? Furthermore, will temperature increases act synergistically with pH effects, and will this alter population demographics? I am studying the effects of ocean acidification on an economically and environmentally significant group of coastal mussels. Results of larval studies will contribute to a model that will assess variability in larval trajectories and its implications for population connectivity. Also, I will investigate the potential stress of acidification and warming on juveniles and adults in order to assess whether these stresses have implications for natural populations.

I will be focusing on the role of pH as an environmental parameter in altering marine ecosystems, specifically through its influence on planktonic dispersing larvae, patterns of connectivity, effects on juveniles and adults, and implications for natural populations.


In vivo experiments will be conducted with three levels of pH and three levels of temperature that are representative of projected surface water changes by 2100 in order to evaluate the stresses experienced by larvae, juveniles, and adults. An existing numerical circulation model (Regional Ocean Modeling System) will be utilized to target the larval trajectories of each species based upon estimations of survival and planktonic larval duration from the in vivo experiments. Additional experiments will investigate the effects of seawater carbonate chemistry have on juveniles and adults. Then by assessing the population demographics of the study species, I will determine the potential implications that pH and temperature will have on natural populations.

Expected Results:

Anticipated results include reduced fertilization, abnormal developmental growth, and extended plankton larval duration of larvae in lower pH treatments. For juveniles and adults I expect altered physiological responses, and a potential reallocation of energy demands that would result in a decrease in gonadal tissue. Incorporating increased temperature into the treatments will aid in discerning whether temperature and pH act synergistically or independently from each other in controlling rates of larval development, and juvenile and adult physiology. If they act synergistically with each other, this could present a nonlinear response and have implications for the persistence of these populations. I also expect that variation in PLD as a response to ocean acidification will alter larval connectivity of the study species’ populations.

Supplemental Keywords:

pH, temperature, larvae, mussels, connectivity, population demographics,

Progress and Final Reports:

  • 2009
  • 2010
  • Final