Tag Archives: plankton

How do we address Hood Canal’s oxygen deficit?

Five years ago, a lot of people were wondering why fish were dying more often in southern Hood Canal during the fall.

Researchers knew that Hood Canal was sensitive to nitrogen. In other words, when nitrogen was introduced to the canal during summer months, nearly all of it was taken up by plankton, which grew into large blooms. When the plankton died, they sank to the bottom, where bacterial decay sucked up the available oxygen.

Beyond that, the questions were numerous: What were the most critical sources of nitrogen affecting the low-oxygen problem? What role does weather and water circulation play? And what can humans do to help the problem — or at least keep it from getting worse.

After a five-year, $4-million study, these questions can be answered with some certainty, as I point out in a story in Sunday’s Kitsap Sun. Now it is time for researchers to convey this information to political leaders and the public, as the Hood Canal Coordinating Council prepares a plan of action.

Scott Brewer, executive director of the HCCC, told me that the eventual plan is likely to include a suite of actions to address nitrogen inputs to the canal, particularly from human sources.
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Oxygen in Hood Canal reaches dangerous levels

I hate to be the voice of doom, but low-oxygen conditions in Hood Canal have never been worse — if you can believe the data gathered since the 1950s, alongside more intense monitoring the past several years.

In the southern portion of Hood Canal, you only need to go down about 30 feet to begin to see stressful oxygen levels in the range of 2 milligrams per liter. For current conditions at Hoodsport, go directly to the Hood Canal Dissolved Oxygen Program’s website, which lists data sent back from the Ocean Remote Chemical Analyzer (ORCA).

Sea creatures are beginning to show signs of stress, according to scuba diver Janna Nichols, who described her findings to me Wednesday after a dive in Hood Canal. She talked about fish “panting” as their gills moved in and out rapidly. Some fish, shrimp and other sealife had moved into shallower water. Watch Janna’s video of a wolf eel and other visuals she captured on the dive.

When low-oxygen conditions are that close to the surface, the danger is that a south wind will blow away the surface layer and bring low-oxygen water right to the surface, leaving fish with no place to go.

Of course, I have no desire to see a massive fish kill, but we already know that fish are probably dying in deep water due to the stressful conditions. I collect this information and offer these reports so that people can alert researchers when something happens. Being on the scene when fish are dying could provide important information about the nature of the low-oxygen problem. For details, please check out my stories in the Kitsap Sun Sept. 7 and Sept. 15 as well as the more technical report from Jan Newton on Sept. 7 (PDF 320 kb).

The phone number to report fish kills or oil spills is (800) 258-5990 or (800) OILS-911

If you haven’t heard, the worst low oxygen conditions normally occur in the fall after a summer of burgeoning numbers of plankton, encouraged by nitrogen and sunlight. By fall, much of the plankton has died and dropped to the bottom, where decay consumes the available of oxygen.

While there are plenty of natural sources of nitrogen in Hood Canal, computer models have demonstrated that human inputs from septic systems and stormwater can push things over the edge in the fall.

Officials are hoping that a new sewage-treatment plant in Belfair will begin to reduce the inputs of nitrogen into Lynch Cove. Another treatment plant is being planned in Potlatch. Stormwater upgrades also are being proposed for Belfair and other areas.

In addition to the low-oxygen problem, Hood Canal was closed to the harvest of oysters after people became sick from vibriosis, a natural bacteria that multiplies in warm conditions. See Kitsap Sun story Sept. 10 and Washington Department of Health maps.

The orange triangles represent this year's composite oxygen levels for the south half of Hood Canal. The latest reading, near the end of August, is the lowest ever seen.

Plankton blooms sometimes offer dramatic visuals

We’re getting reports from all over Hood Canal as well as other waterways about plankton blooms that are coloring the water red, reddish orange and other dramatic colors. See the story in today’s Kitsap Sun.

<i>Plankton bloom near Seabeck yesterday</i><br><small> Photo by Don Paulson, Seabeck</small>
Plankton bloom near Seabeck on Hood Canal yesterday (Click to enlarge)
Photo by Don Paulson, Seabeck

Health authorities and researchers are checking to make sure the plankton are not the kind that create toxins that can poison people, pets or sea creatures. So far, reports indicate that most of the plankton belong to the genus Noctiluca, which don’t appear to cause a safety problem.

I’ve heard some great descriptions regarding “ribbons” of color lining the shore in various places. Folks often have trouble capturing the visual drama in a photograph. A rare exception is a picture we received today from Don Paulson of Don Paulson Photography. Paulson says he captured this picture yesterday at his home near Seabeck.

If anyone else has been able to get a good image, please send it along to me by e-mail, and I’ll post the best.

It’s spring, and the plankton are in bloom in Hood Canal

Don’t be alarmed, but the waters in southern Hood Canal are beginning to look like autumn leaves.

<i>A multicolored plankton bloom has been seen at Twanoh State Park and other areas. </i><br><small>Photo courtesy of Hood Canal Salmon Enhancement Group</small>
A multicolored plankton bloom has been seen at Twanoh State Park and other areas.
Photo courtesy of Hood Canal Salmon Enhancement Group

The color results from the growth of a species of plankton called Noctiluca, which multiplies rapidly in the presence of nutrients and sunlight. Conditions were ideal over the weekend for the water to turn colors — reported as red, orange or yellow. (The photo contains green hues, doesn’t it?)

The plankton aren’t harmful, experts say, and it is too early to say whether the plankton growth we are seeing will contribute to a decline in oxygen levels this fall. These colors are temporary and disappear as the waters get stirred up.

Hood Canal Dissolved Oxygen Program offers more information on its Web site.

Here is a brief story I prepared for Wednesday’s Kitsap Sun:
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