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Factoring Ocean Acidification into California Water Quality Standards

Workshop participants

Oceans absorb approximately one-third of global carbon dioxide (CO2) emissions. While the oceans role in absorbing CO2 has helped mitigate the effects of emissions on earth’s climate, it has caused fundamental changes in ocean chemistry through a phenomenon known as ocean acidification (OA). Emerging research indicates this global challenge will have some of the earliest and most severe effects on the coastal communities and ecosystems of North America’s west coast. 

Fortunately, political momentum is developing in California’s executive and legislative branches to support the development of the best science to address this issue. Specifically, there is state-level traction to identify how best to incorporate OA effects in updated water quality standards under the Clean Water Act and California’s Ocean Plan. Building on this momentum, Stanford’s Center for Ocean Solutions (COS) and the Stanford Woods Institute for the Environment partnered with the Ocean Protection Council and the Southern California Coastal Water Resources Project to host an Uncommon Dialogue on Ocean Acidification: Setting Water Quality Goals. 

Held on October 17–18, 2016, the meeting brought together experts from the academic, NGO, philanthropic, and California, Oregon and Washington state and federal management community to discuss research priorities. The meeting served as a critical starting point for strategic discussion around the need for, and content of, new OA water quality goals. 

Steve Weisberg, Executive Director of the Southern California Coastal Water Research Project, outlined the meeting’s goals: “The workshop aimed to first identify chemical water quality parameters and biological indicators that could be used in the near term for identifying waters threatened by ocean acidification, and then to identify short term research needs to fully describe water quality goals.”

Participants identified measurements of acidity (pH) and the concentration of certain carbon-based minerals in seawater (carbonate saturation state; an environmental factor shown to affect the shell and skeleton forming abilities of coral reefs and other marine organisms) as two chemical parameters that are candidates for near-term adoption as water quality goals. Values for these two parameters can be obtained using available technology, the parameters have been documented through both laboratory and field studies to affect animal and plant life, and their widespread use in ongoing monitoring programs provides context for how the parameters vary naturally in the ocean environment.

The participants also identified the shell condition of pteropods—small marine snails living in the water column—as the most fully developed indicator of OA’s effects on the health of sensitive biological organisms. Pteropod shell condition rose above other candidate biological indicators because pteropods are widely distributed, methods to measure their shell condition are standardized and readily transferable, and shell condition has been linked to organism growth and survival. Pteropod population trends are also predictive of higher-level ecosystem trends and therefore shell condition represents a measurable early-warning indicator of ecosystem health.

“Water quality goals are needed not just for setting state standards for coastal waters, but also for interpreting monitoring data and water quality model outputs. We need some baseline against which to interpret monitoring and modeling results,” said Jenn Phillips, Program Manager at the Ocean Protection Council and California Natural Resources Agency.

Meeting participants developed a list of key research needs, including a better understanding of natural variability in pH and carbonate saturation state along the California coast, standardized operating procedures for measuring carbonate parameters (including pH), and validation of lab findings with field studies.

The meeting also generated a list of actions that should help set the stage for revision or development of new water quality criteria in the state. These included verifying that local nutrient and carbon inputs are meaningful contributors to ocean acidification and can be distinguished from the effects of global CO2 emissions; describing natural variability in the system to demonstrate quantifiable change; validating laboratory findings with field studies; and maintaining motivation and resources by defining the action path for all audiences and connecting the need to species and ecosystems of concern.

“It is exciting to be able to contribute to the bold initiative by the State of California to get ahead of climate change impacts on our oceans,” said the dialogue’s organizer Ali Boehm, the Clare Booth Luce Professor of Civil and Environmental Engineering and Senior Fellow at the Stanford Woods Institute for the Environment.

>Ocean Acidification in Monterey Story

>Ocean Tipping Points