Brown surf attributed to plankton

The foam that people occasionally see in the water and blowing along the coastal beaches is another form of diatom,’ Bolm said.

A photograph showing the brown water appeared in the March 10 edition of the News-Times under the heading, “A muddy-looking surf.” In the caption under that photo, Allen Milligan, an associate professor/senior researcher at the botany and plant pathology departments at OSU, was quoted as saying, “I’ve never seen it that brown just from diatoms,” and he speculated the discoloration could be a combination of diatoms and outfall from the Georgia-Pacific pipeline located offshore from Nye Beach, which discharges water from GP’s mill in Toledo.

Georgia-Pacific officials took exception to Milligan’s statement, saying outfall from their pipeline was not causing the water to turn brown, and that they had been in touch with researchers from NOAA and Hatfield. In an email this week to the News-Times, Jonathan Farmer, public affairs manager for Georgia-Pacific in Toledo, asked the newspaper to set the record straight. He pointed out that GP’s pipeline enters the ocean more than a mile offshore, and the city of Newport has a pipeline in that area that discharges treated wastewater even closer to shore. These pipelines “did not have dark discharge causing the ‘muddy-looking surf,’” he wrote.

Bolm said if the pipelines did contribute to the color of the water in any way, it was by providing nutrients that allowed the diatoms to thrive and multiply. “It’s possible that the plankton is getting some nutrients from the GP outfall, but this is happening in other areas along the coast — it’s not unique to Nye Beach.”

The waters off of Nye Beach do seem to provide the right mix of conditions for such a large presence of the plankton, she said, such as the ocean turbulence at that location and nutrients being washed around in surf rather than sand.

Bolm also said the brownish color could be partially attributed to clay particles caught up in the plankton as it is churned around in the water.

As far as how long these conditions remain visible at any location, Bolm said, “My understanding is that it depends on the weather, but I would say a week on average is a fair expectation. Of course if conditions are favorable, the population could persist for longer, and vice versa.”

Along the Oregon coast, the “brown waves” are more likely to occur during the winter, Bolm said, when the winds are strong and pushing water onshore — building waves — versus the strong winds that push water offshore in the summer. She said her own research takes place a bit further offshore, “so I don’t have firsthand experience sampling these events every year, but I would think there’s a chance of the accumulation happening multiple times a year, or not every year. There are multiple factors at play; not only wind and waves, but nutrients, sunlight, and broader scale events like El Nino.”