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San Diego Scientists Turn Ocean Pink To Study Pollution

Pink dye floating along the shoreline near Imperial Beach.

Credit: Rob Grenzeback

Above: Pink dye floating along the shoreline near Imperial Beach.

If you’re seeing pink at the beach near the U.S.-Mexico border, it’s not your imagination.

Over the last few weeks, scientists from both sides of the border have been injecting the ocean with non-toxic florescent pink dye.

It's part of an unusual experiment to track how pollutants and other contaminants travel across the U.S.-Mexico border. The goal is to use the data to develop computer models that will help water officials make beach closure decisions.

“The U.S. population is concentrated at the coasts,” said Falk Feddersen, a Scripps Oceanography professor and project leader in a press release. “Despite the importance of clean coastal waters to our economy and well-being, declining water quality from pollutants, such as sewage, entering the ocean threatens coastal ecosystems and human health.”

“By tracking dye released both north and south of the border, we can understand the rate of pollutant transport along the coast, how it dilutes, and learn how to develop accurate models for when it will be okay or not to go in the ocean— similar to weather models,” Feddersen said.

The Cross Surfzone/Inner-shelf Dye Exchange is being funded by the National Science Foundation.

The project includes researchers from the Scripps Institution of Oceanography, Jacobs School of Engineering, Autonomous University of Baja California and several other Mexican environmental groups.

Stretches of coastline in South County are often closed after heavy rains due to sewage-contaminated runoff from the Tijuana River.

Falk Feddersen, a Scripps Oceanography professor and project leader, talks with KPBS' Amita Sharma about using pink dye to study ocean pollution.

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