Monterey Bay’s latest trick: turning turquoise

The water in the Monterey Bay, including off Marina State Beach, has been a turquoise color in the past few days because of the presence of coccolithophores, a single-celled phytoplankton that develops scales that reflect the sun. (Vern Fisher – Monterey Herald)

Monterey >> Our corner of the sea is turning a brighter shade of blue.

An odd and little-understood ocean phenomenon is taking place on Monterey Bay right now, and you may have noticed it: the waters are turning an almost tropical turquoise color. Derived from an abundance of a harmless microorganism, the colorful blooms are usually found in the open sea.

But Monterey Bay’s is the second bloom along the California coast in a month. It is due to the presence of coccolithophores, a single-celled phytoplankton that develops hubcap-shaped limestone scales that reflect the sun, turning the water pastel colored.

“The optics of the water when one gets coccolithophores blooms, it looks like this,” said Debora Iglesias-Rodriguez, a biological oceanographer with UC Santa Barbara, noting how odd it is to see a bloom along the shore. “This is really unusual.”

The organisms shed their scales in the water, with the phenomenon usually occurring in northern seas. When you have billions of them, they can impact huge stretches of the open sea, a visual that can be bizarre and stunning in its intensity.

“The blooms are so bright you have to wear sunglasses,” Iglesias-Rodriguez said.

In fact, coccolithophores are responsible for something most people are familiar with: the White Cliffs of Dover, along the English Channel. The striking white cliff faces were created from sediment filled with the organism’s discarded scales.

The first bloom showed up last month in the Santa Barbara Channel. Iglesias-Rodriguez said she is researching why it happened there, including whether the recent oil spill is a factor.

But late last week, it started showing up in Monterey Bay. Satellite data shows the waters from Point Pinos in the south to Natural Bridges State Beach in the north colored a vibrant hue.

Iglesias-Rodriguez is in touch with colleagues at the Monterey Bay Aquarium Research Institute in the hopes of comparing water samples. She said she can only find one unofficial record of the phenomenon occurring off Santa Barbara, dating to the 1990s.

“We are trying to figure out: Why now?” she said.

Coccolithophores seem to thrive when other phytoplankton cannot, particularly when marine phosphorous levels are low. They typically bloom in early summer.

“This would be the right time for them,” Iglesias-Rodriguez said.

This image from Saturday was created using data from NASA’s AQUA satellite, with help from biological oceanographer John Ryan at the Monterey Bay Aquarium Research Institute. The turquoise water is created by the presence of a microorganism. (Courtesy MBARI)

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