In an ambitious, bi-national investigation of how pollution spreads along beaches, Scripps Institution of Oceanography scientists will release pink dye into the ocean north and south of the border three times over the next four weeks.

The spread of the non-toxic dye will be tracked along the shoreline, from boats and Jet Skis, and by airplanes. Study results will be used by policy makers to guide beach closure decisions.

Unhealthy water conditions due to pathogens, sewage, and other contaminants often threaten water quality along the shoreline. This happened earlier this month when San Diego County beaches from the Mexican border to Coronado were closed due to pollutants flooding into the ocean from heavy rain.

“The U.S. population is concentrated at the coasts. 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,” said Falk Feddersen, a Scripps professor.

“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,” said Feddersen.

The National Science Foundation-funded project includes researchers from Scripps, UC San Diego and several Mexican institutions. The study builds on data from a similar use of dye in 2009.

Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.