Tag Archives: Jan Newton

Low-oxygen scenario following unusual course this year in Hood Canal

Death came early to Hood Canal this year, demonstrating just how odd and unpredictable ocean conditions can be.

Fish kills caused by low-oxygen conditions in southern Hood Canal usually occur in late September or October. That’s when low-oxygen waters near the seabed are pushed upward by an intrusion of heavier water coming in from the Pacific Ocean and creeping along the bottom. Winds out of the south can quickly blow away the surface waters, leaving the fish with no escape.

That’s basically what happened over the past month, as conditions developed about a month earlier than normal. South winds led to reports of fish dying and deep-water animals coming to the surface to get enough oxygen, with the worst conditions occurring on Friday. Check out the video on this page by Seth Book, a biologist with the Skokomish Tribe, who found deep-water ratfish swimming near the surface.

The story of this year’s strange conditions actually begins about a year ago and involves a 1,000-mile-long “blob” of unusually warm ocean water off the West Coast. State Climatologist Nick Bond, who coined the term “blob,” explains its formation in an article in Geophysical Research Letters with a summarized description by Hannah Hickey in UW Today.

The warm, low-density coastal waters related to the blob came into Hood Canal on schedule last fall, but they were not dense enough to flush out the low-oxygen waters, according to University of Washington oceanographer Jan Newton.

Hood Canal entered 2015 with the least-dense waters at depth over the past 10 years. They remained in a hypoxic state, meaning that levels were below 2.5 parts per million. Sea creatures unable to swim away can be unduly stressed and unable to function normally at that level. Conditions worsened into the summer, when the hypoxic layer at Hoodsport grew to about 300 feet thick.

By then, the annual intrusion of deep seawater with somewhat elevated oxygen levels was on its way into Hood Canal, spurred on by upwelling off the coast. This year’s waters are more normal in density, though their arrival is at least a month early. By August 9, the hypoxic layer at Hoodsport was reduced from 300 to 60 feet, pushed upward by the denser water.

It’s always interesting to see this dynamic play out. The layer of extreme low-oxygen water becomes sandwiched between the higher-oxygen water pushing in from the ocean and the surface water, which ordinarily stays oxygenated by winds and incoming streams. Without south winds, the middle low-oxygen layer eventually comes up and mixes into the surface layer.

If south winds come on strong, however, the surface layer is blown to the north, causing the low oxygen water to rise to the surface. Fish, shrimp and other creatures swim upward toward the surface, trying to stay ahead of the rising low-oxygen layer. When the low-oyygen layer reaches the surface, fish may struggle to breathe in the uppermost mixing layer. Unfortunately, the fish have no way of knowing that safer conditions lie down below — beneath the low-oxygen layer and within waters arriving from the ocean.

Jan Newton reported that the low oxygen levels in southern Hood Canal earlier this year were the most extreme measured over the past 10 years. So far, however, the fish kills don’t seem as bad as those in 2003, 2006 and 2010, she said.

The graph below shows how the deep layer coming in from the ocean at 279 feet deep contains more oxygen than the middle layer at 66 feet deep. The surface layer, which normally contains the most oxygen, dipped to extremes several times near the beginning of August and again on Friday, Aug. 28. These data, recorded from a buoy near Hoodsport, are considered unverified.

Graph

You, too, can observe oxygen changes in Hood Canal

I’m becoming something of a nerd when it comes to oxygen levels in southern Hood Canal. I’m sure it stems from the realization that we now have the technology to predict when fish will react to low-oxygen conditions by swimming to the surface, acting sluggish and sometimes dying.

Wolf eels at Sund Rocks in Hood Canal are disturbed by low-oxygen conditions.
Photo courtesy of Pat Lynch

In a story published in Monday’s Kitsap Sun, I took a step back from the immediate low-oxygen conditions and discussed our knowledge of Hood Canal, along with plans being formulated to address the low-oxygen problem.

Low-oxygen conditions reared their ugly head during the last week in September (Water Ways, Sept. 27). No major fish kills were reported before things began to improve somewhat by Friday (Water Ways, Sept. 30).

I’m keeping my eye on the charts and graphs and noticed a couple things that we can talk about. Compare the two oxygen profiles below with an eye to the surface conditions at Hoodsport (blue line) and deeper waters there below 40 meters.

Oxygen profile from Sept. 30
Oxygen profile today (Oct. 5)

The first thing I noticed was that the top of the hypoxic layer moved up from about 17 to 10 meters. That means if fish are avoiding that low-oxygen water, they will also move up. As far as I know, divers have not reported any observations to confirm or deny that change. One explanation is that the heavy ocean layer at the bottom is pushing up the entire water column. It also could mean that the surface layer has grown thinner, such as when south winds blow or north winds stop.

Meanwhile, the bottom of that middle hypoxic layer has moved up from about 70 to 50 meters and the edge has smoothed. That is an indication that the heavy ocean water, which contains more oxygen, is mixing with the bottom of the hypoxic layer.

One may also notice that the deep water at Twanoh (turquoise line) has become more oxygenated all the way through and is sharply higher in oxygen at the bottom. Perhaps this is an indication that the heavy ocean water has reached Twanoh and is mixing at the bottom, while winds and tides mix the water at the top.

University of Washington oceanographer Jan Newton has noticed a decline in the oxygen concentration in the middle layer at Hoodsport. She raises the prospect that this could result, in part, from low-oxygen water being pushed back from Lower Hood Canal by the annual intrusion of heavy ocean water. It needs to be checked further, she said.

I hope we get some diver observations this weekend or sooner. In discussing the current conditions with Dan Hannifious of Hood Canal Salmon Enhancement Group, we both wondered when deep-water fish will move back to their normal depth. What would it take for them to break through the middle low-oxygen layer to reach deeper water that is higher in oxygen.

If you would like to become an armchair observer of these conditions in Hood Canal, check out the graphs on the website of the Hood Canal Dissolved Oxygen Program. You’ll have to save old graphs to compare them closely, although another graph on the Nanoos website shows you changes in oxygen levels and other parameters over time for selected depths. (Click on “Regions” then “Puget Sound” and locate the Hoodsport buoy to find the graphs.)

Will the conditions in Hood Canal get better or worse this year? I’ll let you know, but if you see something unusual, feel free to post a comment here.

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.

A poetic approach to the wonders of Hood Canal

Kitsap Sun photo (Click to view fullsize.)

Marc Ramirez of the Seattle Times seems to have discovered Hood Canal for the first time, or maybe he just took a fresh look at it. He begins his travel piece with a colorful and fitting description:

It’s one of Washington’s hidden jewels, a fishhook-shaped natural fjord dividing the Olympic and Kitsap peninsulas. It’s a deep breath, a moment of silence. That place you want to run to, to get away from it all? It’s the Hood Canal.

But while it’s no secret to locals, who cite the glacially carved waterway’s natural features — mountains, forest, wildlife, sunsets, water — as their reasons for living here, what might stand out to visitors is something else entirely: A sense of utter calm.

Jan Newton, a University of Washington oceanographer known for her studies of the canal’s low-oxygen condition, offered her own colorful observation, removed from the usual scientific objectivity:

“Any time humans are in a landscape where there’s a strong scale of the land and you feel very little, you feel really special. It’s like being in a theater — you see so much in front of you.”

For those of us familiar with Hood Canal and it’s many features, Ramirez’ piece offers an opportunity to step back and see the waterway with a newcomer’s eye.

Would anyone care to offer a personal observation about Hood Canal, maybe mentioning a favorite place or a special memory? I would love to see some comments on this.

If you’re interested in my writing about Hood Canal, here are the opening lines from the book “Hood Canal: Splendor At Risk”:

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