Temporary swim ban at 3 local beaches

Sophie Richman noticed the James River behind her Hilton area home take on a red tint Tuesday.

"It looked like someone poured Rit Dye in there," she said.

By Saturday the area around Hilton smelled like dead and decaying fish.

And when Richman took her dog Lucy for a walk down by the riverbank she noticed something odd: crabs and small hogchoker fish seemed to be jumping out of the water only to die on the sand.

"Since I've lived here, and we moved in here in 1995, I've never experienced this," she said.

On Friday, after receiving similar complaints about the color and smell of the James River water, the Peninsula Health District closed the Anderson, Huntington and Hilton beaches to swimming.

The two beaches are expected to remain closed until at least Monday, when new water samples can be tested, said director Dr. David Trump.

"We aren't sure what caused it," Trump said.

Tests done on the water Friday found no evidence of bacteria, which occasionally occurs in the James River and closes beaches, he said.

But they did find higher than normal amounts of fresh water and protoplankton, single-cell plant-like organisms.

That would be constant with what's known as a red tide, or an algal bloom.

Protoplankton live in the water all the time, but when conditions are ideal they can reproduce at an accelerated rate, forming a giant cloud and discoloring the water a deep reddish-brown.

"When conditions are right, they can amplify very, very rapidly," said Jeffrey Shields, a professor with the Virginia Institute of Marine Science.

The exact cause of a red tide, which can last for two to three weeks, is rarely known.

But Shields said that typically the organisms need two things to grow uncontrolled: warm weather and elevated levels of nitrogen in the water.

About 30 percent of the nitrogen found in area waters occurs naturally, Shields said.

The rest is man-made - chemicals that run off the land and into the water from farms, lawns and septic systems.

In fact, Shields said that the higher than normal concentrations of fresh water found in the James last week may be last week's rain water, which could have brought with it the nitrogen that these organisms needed to bloom.

The protoplankton that typically lives in area waters - a dinoflagellata known as Cochlodinium - is not believed to be harmful to humans, Shields said.

But when it dies, bacteria move in to eat the dead plant material, which in turn robs the water of the oxygen other organisms need to live.

"Some animals will not live in that water and they'll end up coming right up on the shore looking for oxygen," Shields said. "That's the really harmful aspect of this."