You are here:
Factors Influencing Trends in pH in the Wootton et al. (2008) Dataset
Citation:
Brown, C. Factors Influencing Trends in pH in the Wootton et al. (2008) Dataset. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R/12/676, 2012.
Impact/Purpose:
Wootton et al. (2008) analyzed an 8-year dataset collected in a tidepool on Tatoosh Island, Washington and found that this region was experiencing a rapid decline in pH, which was an order of magnitude greater than that predicted by models relating atmospheric carbon dioxide (CO2) to oceanic pH levels. In this report, the dataset collected by Wootton is analyzed to assess whether the apparent rapid decline in the pH at Tatoosh Island can be explained by other more localized processes. Analyses presented in this report suggest that pH levels at Tatoosh Island may be influenced by the interaction of the Fraser and Columbia River plumes. The Fraser River has a stronger influence on pH levels at Tatoosh Island than the Columbia River and declining Fraser River flow appears to result in the transport of more low pH water into the vicinity of Tatoosh Island. The analyses presented in this report suggest that climate change might influence nearshore pH levels through alterations in river discharge, modulating the degree of coupling between the nearshore and upwelling of deep low pH water.
Description:
In this report, the dataset collected by Wootton at Tatoosh Island during 2000 through 2010 is analyzed to assess whether the apparent rapid decline in the pH data can be explained by other more localized processes. Specifically, we focused on the role of river discharge on pH levels at Tatoosh Island. In addition, we analyzed temporal trends in another long-term dataset collected in Yaquina Estuary, Oregon, to assess whether it is appropriate to extrapolate the long-term temporal trend observed at Tatoosh Island over a larger region.