The late-night mist glides along the water, cloaking a black creature moving swiftly through the murk. The creaks and moans of the carcasses of rusty bikes are barely audible beneath the cries of frogs and the chirps of birds.

This is not your bathtub, kids; this is the UCSB Lagoon.

Though many run quickly past it late at night for fear of running into the terrible Swamp Yang or complain about its stench at certain times of the year, the Lagoon is actually a healthy habitat, carefully watched and tended by researchers from the campus Cheadle Center for Biodiversity and Ecological Restoration. And the most dangerous creatures in or around it are the lurking skunks or raccoons at night, or the abundant poison oak on Lagoon Island, said Natural Areas Director Lisa Stratton.

Formed eons ago by Ice Age rivers and volcanic uplift, what is now the Lagoon gradually became a dry salty bed seven feet above sea level. Sand deposits partially separated it from the ocean. Water filled it when it rained, but summer inevitably chased the moisture away.

When UCSB founders purchased the campus from the U.S. Military in the mid-1950s, the area of the “lagoon” was more of a salty marsh, smelly and not very pretty to look at.

Researchers began the long process of revitalizing it in 1964, completing the cut-off from the ocean using sand. At 800 gallons per minute, the researchers pumped in purified sea water used by the Marine Science Institute on the east side of campus. They built a weir on the west side to let excess water drain into the ocean.

There are eight storm drains that feed the Lagoon from different areas around campus. Although the Lagoon water is usually salty, Stratton said rain runoff can turn the water very fresh. It is this mixing of different nutrients in the water as well as the warmth that creates algae, which becomes more abundant in the summer heat. When the algae dies, it forms black mats that can smell unpleasant, however, the Lagoon normally smells just like the ocean.

In an effort to curb the nutrient level in the lagoon, Stratton said the center created a system of bioswales in Manzanita Village, where runoff flows through a bed of native plants before it reaches the Lagoon.

The water quality is safe, and is only two meters at its deepest, but Stratton said it’s not really for swimming. Indeed, the Center pulls out at least 12 bikes a year from the Lagoon, so there’s no telling what a swimmer might find.

“You can’t really drown, but people are not encouraged to go in,” Stratton said. “It’s a little murky.”

The UCSB Crew team uses the Lagoon a few weeks out of the year for practice, but most of the year their gray plastic dock is a prime spot for coastal birds. The dock gets moved out and anchored to the middle of the lagoon to confine the birds, their guano – and their stench – to the water. Birds also frequent the shallow manmade islands along the water’s edge, foraging for the five types of fish that swim around the Lagoon’s waters.

Birds also like the poison oak that naturally grows on Lagoon Island. If you’re running off your Freshman 15 with a lap around the lagoon sometime this year, just remember, leaves of three, let them be.

“Unfortunately, poison oak is a bird habitat, so we’re not going to control it,” Stratton said.

The researchers do try to control the weeds, non-native plants and iceplant that pop up around the Lagoon and on the island. This summer, the California Coastal Commission approved a proposal by the center and graduate student Alice Levine to do a controlled burn once a year for three years to try to curb the unwelcome visitors and encourage more native plants to live in the area. Last fall, the team planted 1,000 oaks along the west side of the Lagoon, which are now 20 to 40 centimeters high and visible because they’re still in their blue protective tubes.

The concrete-covered area by Campus Point is one of the next projects on the Cheadle Center’s list. The concrete, left over from when the campus was owned by the military, covers a Chumash Indian archaeological site. Stratton said Native Americans used the plants and resources on Lagoon Island long before local community members used the paths for recreation.

The work in and around the Lagoon is ongoing, and Stratton said there are positions available through the center on an intern or volunteer-basis to help keep the Lagoon beautiful and surrounded by native plants.

Even if it is a little scary at night, UCSB is the only UC that can boast something as cool as a lagoon on campus and an ocean bordering on two sides. And don’t worry, the Swamp Yang hasn’t been seen for many years.