A cruise run by the Aquarium of the Pacific in Long Beach, Calif., exposes guests to the "urban ocean" in the country's biggest shipping terminal.
In front of the aquarium, school kids are running around, eager to go inside and pet the sharks and see the penguins. There's also a marina, where a small passenger boat called the Cristina shoves off from sunny Shoreline Aquatic Park.
Instead of taking a left for a scenic cruise down along the famous beaches of Southern California, it veers right, and into the country's busiest shipping terminal and the mouth of the L.A. River.
"This river right here will dump into the ocean, bringing lots of stuff with it, including trash and chemicals," tour guide Kera Mathes explains.
Mathes, an educator with the aquarium, says those chemicals include domoic acid, which has been blamed for sickening the local sea lion population.
"Pretty much any of the trash that you see today in the water will probably have come from this L.A. River," she tells the group. "It's not necessarily the beach-goers, but it's people that live all around the watersheds, which could be all the way up into the mountains."
The 20 million people living in the greater Los Angeles area do a lot — intentionally or not — that harms this ocean. The tour is an eye-opener for Cristina Duffy, who brought her young daughter, Emily, aboard.
"When we were at the pier, she saw the bottles, the trash in the water, and she was really concerned about that," Duffy says.
Mathes says a lot of the pollution problems here stem from the 1930s, when the Navy built an eight-mile strip of breakwater. It acts like a big net, catching the trash, spilled fuel and all sorts of nasty things from all the industrial activity here.
But Mathes says the breakwater also allowed the ports of Los Angeles and Long Beach to become the busiest in the nation.
"If you have something that doesn't say 'Made in the USA,' chances are it came through this port," she says, "including our clothes, shoes, some food, some of our electronics, basically comes through this port. Half the stuff is right through here."
This summer, the passenger boat Cristina will be a common sight, chugging between the giant cargo ships and cranes, giving aquarium visitors a rare, close-up look at the ports and the environment around them.