Working with Grant on the project are UCI environmental engineer Brett Sanders, oceanographer Clinton Winant and biological oceanographer Lisa Levin of the Scripps Institution of Oceanography in La Jolla, and marine ecologist Richard Ambrose of UCLA. The group will study the Tijuana Estuary, San Diego Bay, Mission Bay, San Dieguito Lagoon, Upper/Lower Newport Bay, the Santa Ana River sloughs, the Ballona wetlands and the Mugu Lagoon.
Researchers are motivated by an alarming increase in the number of beaches in California that are posted as unfit for swimming because of high levels of fecal pollution. The UCI-led study will help resolve a growing controversy over whether coastal wetlands filter out fecal pollution from urban sources or generate it.
"We've known for some time that coastal wetlands are a critical habitat for rare and endangered species," Grant said. "The issue is whether animal feces released from coastal wetlands are contributing to beach closings in Southern California."
Traditional thought is it that wetlands are highly desirable both for the habitat they provide and because they act like nature's filter removing nutrients, heavy metals and pathogens from contaminated surface water.
"The problem is that virtually everything we know about wetland treatment is based on studies of freshwater systems, not the tidal saltwater marshes found along the Southern California coast," Ambrose said.
"A key issue is the amount of time water spends in the wetland," Levin said. "Longer water residence time will enhance deposition of contaminants and allow bacteria to die. This project will provide the primary data necessary to restore coastal wetlands so that they minimally impact and ideally improve coastal water quality."
In recent research, Grant and Sanders found that bird droppings in the Talbert Marsh contributed fecal matter to coastal Huntington Beach where high bacteria levels have led to numerous beach postings over the past three years. "We want to know if our results at Talbert Marsh are unique to that one location or if this is a more widespread problem," Sanders said.
Specifically, the research group will collect data on how:
- wetland landscape and circulation features affect fecal pollution levels;
- specific wetland intervention strategies, such as restoration of tidal flushing, influence coastal water quality;
- the wetland ecology influences pollutant removal rates;
- the surrounding watershed affects pollutant levels in the wetland and adjacent coastline.
"The results of this research project will be of immediate use for local, state and federal agencies concerned with coastal wetland restoration, beach water quality and coastal zone management," Winant said.
The Henry Samueli School of Engineering encompasses five departments: biomedical engineering, civil and environmental engineering, chemical engineering and materials science, electrical and computer engineering, and mechanical and aerospace engineering. The school also is home to numerous research centers, including the Center for Pervasive Communications, National Fuel Cell Research Center and Center for Biomedical Engineering. Additional information is available at www.eng.uci.edu.
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