Tag Archives: Coccolithophore

Hood Canal changes color again, thanks to plankton bloom

Hood Canal has changed colors again, shifting to shades of bimini green, as it did in 2016, when satellite photos showed the canal standing out starkly among all other waters in the Northwest.

Hood Canal has changed colors as a result of a plankton bloom, as shown in this aerial photo taken in Northern Hood Canal.
Photo: Eyes Over Puget Sound, Washington Ecology

The color change is caused by a bloom of a specific type of plankton called a coccolithophore, which shows up in nutrient-poor waters. The single-celled organism produces shells made of calcite, which reflect light to produce the unusual color.

Observers are now waiting for the clouds to depart, so we can get new satellite images of the green waters.

The plankton bloom started June 1 in Quilcene and Dabob bays, according to Teri King of Washington Sea Grant. It came about a week earlier than last year and has since spread through Hood Canal. Observers in the Seabeck area reported seeing the bloom the past few days. The bimini green color, which gets its name from an island in the Bahamas, is especially noticeable when the sun comes out.

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Hood Canal changes color from growth of white plankton

Hood Canal cloaked in light green from heavy plankton growth. NASA image: Jeff Schmaltz, LANCE/EOSDIS Rapid Response
Hood Canal cloaked in light green from heavy plankton growth.
NASA image: Jeff Schmaltz, LANCE/EOSDIS Rapid Response

From space, Hood Canal is easily recognized by its new shade of bimini green, a color that stands out clearly from the rest of Puget Sound and the Pacific Ocean, as shown in the photo above.

The color is caused by a large bloom of coccolithophore, a single-celled phytoplankton bearing a shell made of white calcium carbonate.

A more detailed image of the plankton bloom. NASA image: Jesse Allen, using Landsat data from USGS
A more detailed image of the plankton bloom.
NASA image: Jesse Allen, with Landsat data from USGS

Teri King of Washington Sea Grant spotted the unusual color more than a week ago from the ground while driving along Hood Canal.

“I thought to myself, ‘Am I dreaming of the Cayman Islands?’” she reported on her Facebook page. “I pulled over to the side and took a few photos to document my observations. I then had an opportunity to grab a water sample. Yep, a Coccolithophore bloom from Quilcene to Lilliwaup.

“It is hard to miss a bloom of this color,” Teri continued on Facebook. “We don’t see them often, but when we do it is remarkable. The water takes on a tropical blue green appearance with white speckles.”

Scanning electron micrograph of plankton Emiliania huxleyi
Scanning electron micrograph of plankton Emiliania huxleyi
Image: Alison R. Taylor, U. of North Carolina Wilmington

The photo from space (top) was taken last Sunday from NASA’s Aqua satellite with equipment used to capture the natural color. On Wednesday, a more detailed image (second photo) was taken from the Landsat 8 satellite.

Reporter Tristan Baurick describes the phenomenon in yesterday’s Kitsap Sun. The single-celled plankton are not harmful to people or animals, so the bloom won’t affect shellfish harvesting. Hood Canal, as we’ve discussed many times, is prone to low-oxygen conditions, often exacerbated by massive blooms of plankton, which reduce oxygen through the process of decay.

The last major bloom of this kind in Hood Canal was noted in northern Hood Canal during the summer of 2007. Samples taken at that time showed the species of coccolithophorid to be Emiliania huxleyi, according to a report for the Hood Canal Dissolved Oxygen Program.

NASA’s photos and description of the latest bloom can be found on the Earth Observatory website, which also includes just about all you need to know about coccolithophores.

Hood Canal is green alright, up close and far away. Photo: Meegan M. Reid, Kitsap Sun
Hood Canal is green alright, up close and far away.
Photo: Meegan M. Reid, Kitsap Sun