In what is becoming an annual event, portions of Hood Canal have
changed colors in recent days, the result of a large bloom of
armored plankton called coccolithophores.
Coccolithophore from Hood
Canal’s Dabob Bay viewed with scanning electron microscope.
Image: Brian Bill, Northwest Fisheries Science
Center
Teri King, a plankton expert with Washington Sea Grant, has been
among the first to take notice of the turquoise blooms each year
they occur.
“Guess who is back?” Teri wrote in the blog
Bivalves for Clean Water. “She showed up June 24 in Dabob Bay
and has been shining her Caribbean blueness throughout the bay and
spreading south toward Quilcene Bay.”
Yesterday, I noticed a turquoise tinge in Southern Hood Canal
from Union up to Belfair, although the color was not as intense as
I’ve seen in past years.
The color is the result of light reflecting off elaborate
platelets of calcium carbonate, called coccoliths, which form
around the single-celled coccolithophores. The species in Hood
Canal is typically Emiliania huxleyi.
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.
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, 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
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
