Microscopic plankton turns Hood Canal a milky, greenish tint

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NASA photo showing a detailed view of the bloom on July 27th, as observed by the Operational Land Imager (OLI) on the Landsat 8 satellite.

BRINNON  (AP)  –  A rare bloom of light-colored phytoplankton has turned most of the Hood Canal green.

According to NASA scientists, on July 21st, Teri King of Washington Sea Grant caught a glimpse of the bloom while driving along Hood Canal.   She was headed to a training session for “Sound Toxins,” volunteer-based monitoring program that documents harmful algal blooms, unusual bloom events, and new species.

King stopped and took a water sample, confirming the color was due to a coccolithophore bloom.   That’s a big word for microscopic plankton, that’s plated with white calcium carbonate.  The plates can add a milky, turquoise color to the water.

Scientists say the microscopic, one-celled organisms coat themselves in limestone plating, the reason for the brilliant color.  King equated the color to that of water surrounding the Cayman Islands, a shade of teal somewhere between lime and turquoise.

“It is hard to miss a bloom of this color,” King wrote on Facebook, “We don’t see them often, but when we do it is remarkable.”

The last large bloom of coccolithophore in Hood Canal was in July and August of 2007.

Last month, NASA’s Moderate Resolution Imaging Spectroradiometer, an instrument on the agency’s “Aqua” satellite took a natural-color image of the bloom.

The second image shows a more detailed view of the bloom on July 27 as observed by the Operational Land Imager on the Landsat 8 satellite.

NASA’s “Earth Observatory” web page quotes Jan Newton, an oceanographer at the University of Washington, who says Hood Canal can be quite a productive area for this type of bloom.

“It has also been very sunny lately, so that begets blooms,” she said.

Scientists are concerned about blooms in Hood Canal since they they could lead to hypoxia, a depletion of oxygen in the water.

The water has changed colors from the Hood Canal Bridge to Tahuya, at the southern end of the canal.

NASA satellite images show the deepest green hues in and around Dabob Bay and Seabeck.

Officials say the bloom isn’t a threat to humans and shellfish can still be harvested.