Nitrate Level Up, Boosts Algae Growth

Warm temperatures have brought out more than bikers and joggers along Upper Newport Bay this season. A new stretch of green algae has crept up, bringing with it a stench that has residents complaining.

“This is probably the worst I’ve seen it,” said Dan Weymouth as he stopped for a break from jogging along Jamboree Road where it crosses over the San Diego Creek Channel. Weymouth said he has lived in the area for seven years and jogs almost daily.

“I’ll probably find another route until this thing goes away,” he said.

The problem is not only an aesthetic one for the residents and businesses bordering the bay, but could also pose a health threat to the fish there, according to the state Water Quality Control Board.

“It can deplete the dissolved oxygen in the water and hurt the fish and wildlife in the area,” said Hope Smythe, an environmental specialist with the state agency.

Although the algae is present throughout the year, low water levels and high temperatures at this time of year increase the algae growth, Smythe said.

The most likely culprit are nurseries and other agricultural users along the San Diego Creek, whose runoff of fertilizers spawns the growth. Since 1986, the state has regulated the amount of nutrients those users discharge.

“Our data is telling us that the nitrate concentrations are as much as 10 times greater than any of the other channels, and that’s exceedingly high,” said Lane Waldner, supervisor of environmental studies with the county Environmental Management Agency.

Water samples from the upper and lower bay show that there are 100 milligrams of nitrates per liter, compared to the 10-year average of 60 milligrams per liter, Waldner said.

Because of the drastic increase in algae this year, the state and county agencies will team up to test the water at four different sites along channels of the creek for other sources of the problem.

“One of the things that we’re thinking is it might be rising ground water that is heavy in nitrates,” Smythe said, adding that development in the Irvine area may be causing the ground water to rise.

Waldner suggested that the problem also may stem from the rise of the perched water table which is just below the surface and can contain a high level of nitrates.

If the source is an agricultural user, the state can enforce more water-efficient methods of irrigation which reduce the amount of overflow from the fields, Waldner said. Many nurseries and orchards along the creek have installed drip irrigation systems to achieve this, he said.

Prevention is the only way to keep the high concentrations of nitrates out of the bay, Waldner said.

“There’s nothing that we can really do,” he said. “It’s not like you have another chemical that you can go in there and treat it with.”

Fish and other wildlife may be threatened if the algae continues to grow at a high rate, dies off and becomes food for bacteria that feed off of it at the bottom of the bay, Waldner said. The bacteria use up oxygen that is essential for the fish.