Scripps oceanographer helps Navy SEALs safely swim to shore

SanDiegoSource: Scripps oceanographer helps Navy SEALs safely swim to shore
It seems like fluorescent pink dye and Navy SEALs would have very little to do with each other. But for Bob Guza, a scientist at the Scripps Institution of Oceanography, they do.

Guza studies how waves and currents affect the spread of contamination along the ocean’s beaches and receives Navy funding for that work because it benefits sailors, especially Navy SEALs, who swim onto foreign shores.

“In a lot of places, raw sewage and worse is routinely dumped in the water,” he said. “It’s nasty.”

Guza was among five San Diego scientists who received Department of Defense grants through the Defense University Research Instrumentation Program last week. His $301,400 award will allow him to buy refined instruments to study the composition of ocean water.

That’s where the pink dye comes in.

Although Guza studies the spread of pollution, he said he cannot work with actual contaminants because “no one would work for me.”

Instead, he employs the dye as a type of fake pollution to simulate a scenario involving a contaminant leak or spill. Guza and his team trickle the dye into the ocean and then ride Jet Skis equipped with GPS and instruments called fluorometers to measure the amount of dye in the water.

The fluorometers gauge how much light is reflected by the dye as a way of determining the amount of dye in the ocean water, and were paid for by Guza’s most recent Defense University Research Instrumentation Program grant. They can take measurements five times a second, and then that information, along with the Jet Ski’s GPS position, is transmitted in real time to Guza’s lab.

These sophisticated measurement techniques collect far more data points with much greater accuracy than old methods, Guza said.

“Imagine armies of graduate students running around with bottles, picking up water samples and us having to guess where they are,” he said. “That’s history.”

Guza and his team do much of their research at Imperial Beach, where contamination from the Tijuana River can sometimes pollute the shoreline and give swimmers and surfers infections.

“When it rains, you do not even want to look at that water,” Guza said.

The team released the dye about five miles from the Mexican border and found it moved fairly quickly during a southern swell, reaching the Imperial Beach pier in two hours. Also, its dilution was “not gigantic,” Guza said, meaning it remained fairly concentrated.

Next, the researchers will head to Marine Corps Base Camp Lejeune in North Carolina, where a river inlet on the coast will allow them to study what the dye does in a different set of currents.

All of this information is compiled into computer models developed by Falk Fedderson, another Scripps researcher, to create simulations and estimates of how pollution travels along foreign shores where Navy SEALs might need to land.

“By understanding what happens in Imperial Beach, we can try to decide what will happen in places where you can’t put dye in the water and use Jet Skis because people on shore will shoot you,” Guza said.

But, he cautioned, creation of these models is not easy and requires as much hard data as possible.

“It’s not a simple one step from Imperial Beach to Vietnam or North Korea,” he said. “But we can gather enough information to make inferences about what happens there.”

Although ocean conditions can vary between U.S. and foreign beaches, the fundamentals of water’s behavior are the same everywhere, Guza said.

“Waves are waves,” he said.