Category Archives: Pollution and spills

Stormwater projects in Silverdale offer hope for a degraded Clear Creek

Detailed planning and design, followed by thoughtful construction projects, have begun to tame the stormwater menace in Clear Creek, an important salmon stream that runs through Silverdale in Central Kitsap.

A renovated stormwater pond at Quail Hollow near Silverdale includes a walking trail and enhanced wildlife habitat. Photo: C. Dunagan
A renovated stormwater pond at Quail Hollow near Silverdale includes a walking trail and enhanced wildlife habitat. // Photo: C. Dunagan

Stormwater has been identified as the greatest pollution threat to Puget Sound. In Kitsap County, many folks believed that the dense development pattern in and around Silverdale has doomed Clear Creek to functioning as a large drainage ditch for runoff into Dyes Inlet.

But reducing stormwater pollution is not beyond the reach of human innovation, as I learned this week on a tour of new and planned stormwater facilities in the Clear Creek drainage area. The trick is to filter the stormwater by any means practical, according to Chris May, director of Kitsap County’s Stormwater Division and a key player in the multi-agency Clean Water Kitsap program.

Projects in and around Silverdale range from large regional ponds of several acres to small filtration devices fitted into confined spaces around homes and along roadways.

On the small side, below-grade planter boxes have been installed along Silverdale Way, Bucklin Hill Road and Ridgetop Boulevard to filter runoff flowing into storm drains. One can spot these innovative devices by looking for the protective “cages” that keep people from trampling the young plants.

Rain gardens, another filtering technique, can be installed in people’s yards, along a roadway or anyplace where they can capture a relatively small volume of stormwater. Several housing developments, including Shadow Glen north of Silverdale, have been given the name “green streets” for infiltrating stormwater into the ground rather than passing it into Clear Creek.

On a somewhat larger scale, one strategy widely used in Kitsap County is to reconstruct stormwater ponds in old developments. Old stormwater facilities typically contain a single open pond surrounded by a chain link fence. Such ponds can be enlarged and divided into sections, known as cells. Contaminated sediments settle out in the first cell before the water passes into the second cell, and so on.

The old “stormwater prisons,” as Chris May calls them, may slow down the flow of water, but they have limited abilities to reduce pollutants. New ponds are built more like miniature wetlands, where vegetation helps to settle and absorb the toxic runoff.

Often the edges of an old pond can be sloped more gradually than what was done in the original construction. That reduces the drowning hazard of the old ponds and allows the chain link fencing to be eliminated. Many of the new ponds are now surrounded by a split-rail fence.

Tuesday’s tour, which included public officials and interested citizens, stopped at the Quail Hollow development north of Silverdale, where an old pond was turned into a new wetland with high-tech functions — including a metered discharge and solar-powered aerator. The aerator boosts oxygen levels to keep the water from becoming stagnant during low-flow periods.

A walking trail, which loops around Quail Hollow Regional Pond, will eventually connect to the Clear Creek Trail. As people on the tour walked around the pond, a great blue heron gazed out from the middle of the stormwater wetland.

Amenities like the walking trail and improved wildlife habitat make the new stormwater ponds more appealing to nearby residents, Chris noted.

“I’m told by the birders that this is a nice place to watch birds,” he said.

The next “stormwater park” to be developed will be at Whispering Firs north of Silverdale. It will be another natural pond surrounded by a split-rail fence with a trail eventually connecting to the local trail system.

The Duwe'iq stormwater project near Ross Dress for Less treats stormwater from two nearby shopping centers. Photo: C.Dunagan
The Duwe’iq stormwater project in Silverdale’s commercial district treats stormwater from two nearby shopping centers. // Photo: C.Dunagan

Another multi-celled stormwater system was constructed on vacant land behind two shopping centers in Silverdale’s commercial area. The project, adjacent to the Clear Creek Trail on the west side of the stream, captures water from the adjacent parking lots and includes a trail connection between T.J. Maxx and Ross Dress for Less.

Chris also showed the group several large culverts, which replaced small ones that had impeded the passage of salmon. One culvert on Sunde Road was replaced with a foot bridge for students going to and from Clear Creek School. Neighbors supported the project, because it eliminated a road that was used as a shortcut by motorists passing through the neighborhood on the way to the school, Chris said.

“A question you should always ask,” he said, “is ‘Do you really need this road?’”

Eliminating the road also created a safe place for people to watch salmon swimming in Clear Creek and a place for students to release salmon as part of the Salmon in the Classroom program.

Tuesday’s tour ended at the Clear Creek floodplain project, which I discussed in Water Ways last September. That $3-million project involved the removal of 30,000 cubic yards of material across 21 acres, including the former Schold Farm on the west side of Silverdale Way and the Markwick property on the east side. The project is designed to slow the flow of water downstream while providing a rich habitat for fish and wildlife.

Rocky Hrachovec, principal engineer for Natural Systems Design, said the key to restoration projects is to understand the history of an area, including the former elevations of the stream at various locations.

“It’s important to understand what was here before and how close we can get to that,” he said. “For salmon, you want some places with shallow, fast water and other places with deeper, slower water.”

During heavy rains, Clear Creek is expected to spill over its banks within the restored floodplain and even shift the location of its streambed over time. Logjams have been carefully located to create hard points to confine the flow within the property, he said. The restored floodplain will essentially store excess stormwater and release it slowly back into Clear Creek.

Andy Nelson, director of Kitsap County Public Works, said the efforts to restore Clear Creek did not come about by accident.

“Everything we have seen here today is the result of a thought process, a vision,” Andy said, commending Chris May for his leadership and the hiring of innovative design teams and construction firms.

Andy also gave credit to other innovators, including those who developed a nursery to produce the wetland plants used in many of the projects and those who organized volunteers to safely capture fish so that they wouldn’t be killed during construction. He also commended many others — from volunteers to construction companies to elected officials.

Clear Creek is not the only watershed in Kitsap County where stormwater is being tamed by removing its powers of pollution and erosion, but it stands as an example of what can be done in heavily urbanized watersheds. While habitat loss along the stream cannot be easily replaced, the various stormwater projects go a long way to restoring the health of Clear Creek.

Invasive species need to be on Legislative agenda

With invasive green crabs entering Puget Sound from the north and invasive mussels discovered in Montana to the east, the Legislature will be called on to make some critical funding decisions to ward off potential invaders.

Zebra mussels cover a native mussel in the Great Lakes. Photo: U.S. Fish and Wildlife Service
Zebra mussels cover a native mussel in the Great Lakes. // Photo: U.S. Fish and Wildlife Service

Green crabs and freshwater zebra and quagga mussels are not the only aquatic invasive species of concern. As I described in a story published in the Encyclopedia of Puget Sound, state officials worry about the potential import of all sorts of harmful species via ballast water and the hulls of vessels.

To fully address the threats through prevention and enforcement, the Washington Department of Fish and Wildlife estimates that $5.2 million per year is needed. That would move Washington ahead of Oregon and Idaho in addressing the problems. Each of those states spent about $1.3 million in 2014, while California spent about $10.7 million. Washington’s current budget for dealing with aquatic invasive species is one of the lowest in the country at $900,000 a year.

Increases in the program would be phased in over six years, increasing from $900,000 a year in the current budget to $2.3 million in the next biennium, according to a proposal to be submitted to the Legislature. It would go to $4.7 million five years from now.

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New toxic chemical law begins to review most-dangerous compounds

The first 10 toxic chemicals to be reviewed under the amended Toxic Substances Control Act were announced this week by the Environmental Protection Agency. After review, these chemicals could be banned or significantly restricted in their use.

Photo:André Künzelmann, Wikimedia commons
Photo:André Künzelmann, Wikimedia commons

As specified by law, the first 10 chemicals were chosen from 90 listed in the TSCA Work Plan, based on their high hazard and the likelihood of human and environmental exposure.

Incidentally, seven of the 10 chemicals to be reviewed are contaminants that have reached sources of drinking water at various sites across the country. Six of the seven are known or suspected of causing cancer in humans.

These are the seven chemicals known to contaminate drinking water:

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What comes next under water-quality standards imposed by the EPA?

The Environmental Protection Agency approved new water-quality standards for Washington state this week, overriding a plan approved by Gov. Jay Inslee and the state Department of Ecology.

It was a rare posture for the EPA. Now the state will be pressured to appeal the EPA standards to federal court. Cities and counties as well as some industrial organizations are clearly unhappy with the EPA’s action, while environmental and tribal representatives got most of what they wanted.

The basic structure of polychlorinated biphenyls, where the number and location of chlorine atoms can vary.
The basic structure of polychlorinated biphenyls, where the number and location of chlorine atoms can vary.

The EPA action is especially unusual, given that this state is known for some of the strongest environmental regulations in the country. After much dispute, Ecology finally agreed to much higher fish-consumption rates without increasing the cancer-risk rate, leading to more stringent standards for many of the chemicals. But Ecology had its own ideas for the most troublesome compounds with implications for human health. They include polychlorinated biphenyls (PCBs), arsenic and mercury. For background, see Water Ways, Oct. 18, 2015.

Some news reports I saw this week said EPA’s action will lead to salmon that are safer to eat. But that’s not at all certain, and opponents say it is unlikely that the revised limits on chemical pollution will have any practical effect on compounds that affect human health.

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Understanding how rogue chemicals affect people and marine life

Scientists are just beginning to understand the profound impact that synthetic chemicals are having on humans and other animals in the Puget Sound region.

As a major predator, harbor seals accumulate more than their share of toxic chemicals, including flame retardants. A legal ban on certain chemicals seems to be reducing levels in their tissues. Photo: hj_west, www.flickr.com/photos/hjwest/
As a major predator, harbor seals accumulate more than their share of toxic chemicals, including flame retardants. A legal ban on certain chemicals seems to be reducing average levels in their tissues.
Photo: hj_west

My latest story for the Encyclopedia of Puget Sound addresses so-called chemicals of emerging concern. Please check out “Concerns rise over rogue chemicals in the environment.”

While talking to researchers and investigating a variety of biologically active compounds, I began to realize the complexity of the body’s internal chemistry. I thought I knew something about the endocrine system, but I never fully considered how one hormone can trigger responses in multiple organs, including the release of additional hormones, even creating feedback loops.

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Death of female orca with young son raises worries about the future

It has been hard to take the news that J-28, a 23-year-old female killer whale named Polaris, is now missing and presumed dead — even though I knew this news has been coming since August. It now appears likely that her 11-month-old son J-54, named Dipper, will not survive either.

On Oct. 2, J-28, named Polaris, was photographed with an indentation behind her blow hole, a condition known as “peanut head.” Polaris has now been confirmed as dead, and her son is probably dead as well, researchers say.
On Oct. 2, J-28, named Polaris, was photographed with an indentation behind her blow hole, a condition known as “peanut head” and related to malnutrition. Her 11-month-old son, shown with her, also was struggling to survive. Polaris has now been confirmed as dead, and researchers say her son is probably dead as well.
Photo: Ken Balcomb, Center for Whale Research

I sadly reported on Polaris’ “super-gaunt” condition in Water Ways (Aug. 24) after talking to Ken Balcomb of the Center for Whale Research. Until recently, various whale-watching folks, including CWR researchers, have reported that Polaris was still alive. She was generally seen moving slowly and in poor shape, but at times she seemed to have more energy, raising hopes that she might recover. But the last sighting of Polaris was Oct. 19 in the Strait of Juan de Fuca.

During a press conference Friday, Ken announced the death of Polaris, as he spoke out to raise awareness about the plight of Puget Sound orcas.

Ken said Dipper’s sister and aunt were attempting to care for the young orphan, but no other lactating females have moved in to provide milk, so he likely will die if he is not already dead.

Ken read a personally penned obituary for Polaris, noting that she was popular with whale watchers, in part because she was easily identified by a nick in her dorsal fin. She acquired the distinctive mark when she was nine years old.

At the press conference, Ken talked about the most concerning problem facing the orcas: a shortage of chinook salmon, their primary prey. The food shortage is exacerbated when the whales burn fats stored in their blubber, causing the release of toxic chemicals from their blubber into their bloodstream. Chemicals can affect the immune and reproductive systems, as well as other hormonal systems.

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A difference between chum and coho salmon may be in their blood

On the outside, chum and coho salmon don’t seem all that different from one another, not when you consider the variety of fish in Puget Sound — from herring to halibut along with dozens of other odd-looking creatures (EoPS).

But we know that if you place coho in stormwater taken from a heavily traveled roadway, the coho are likely to die within hours. But if you do the same thing with chum, these hardy fish will barely notice the difference.

In this photo taken two years ago, Jenifer McIntyre describes her discoveries about rain gardens at the Washington Stormwater Center in Puyallup. Photo: Meegan Reid, Kitsap Sun
In this photo taken two years ago, Jenifer McIntyre describes her discoveries about rain gardens at the Washington Stormwater Center in Puyallup.
Photo: Meegan M. Reid, Kitsap Sun

Researchers began to observe the varying effects of pollution on different species of salmon years ago. In 2006, I reported on studies by researcher Nat Scholz of the National Marine Fisheries Service, who discovered that coho would swim into Seattle’s heavily polluted creeks to spawn, but they wouldn’t get very far. Within hours, they would become disoriented, then keel over and die. (Kitsap Sun, June 10, 2006)

Later, Jenifer McIntyre, a researcher with Washington State University, collaborated with Scholz to refine the studies, exposing adult coho and later young coho to stormwater under controlled conditions. Much of that work was done at the Suquamish Tribe’s Grover’s Creek Hatchery in North Kitsap. The researchers also measured the physiological effects of pollution on zebrafish embryos during their early stages of development.

Working at the Washington Stormwater Center in Puyallup, Jen made a remarkable discovery that has dramatically changed people’s thinking about stormwater treatment. She found that if you run the most heavily polluted stormwater through a soil medium containing compost, the water will no longer have a noticeable effect on the sensitive coho. Rain gardens really do work.

Jen’s findings and related stormwater issues were described in a story I wrote two years ago for the Kitsap Sun, “Stormwater solutions key in fight for Puget Sound.” The story is part of a two-year project we called “Taking the Pulse of Puget Sound.”

Now, Jen, who recently joined the faculty of WSU, is beginning a new phase of her research, probing deeper into the physiological responses of coho salmon when exposed to polluted stormwater. She told me that the varying responses of coho and chum offer clues about where to look for problems.

“It is very interesting,” she said. “As biologists, we understand that there is variability among species. But we would expect, at least among salmon, that things would be pretty much the same.”

Researchers in Japan have discovered that different kinds of fish have different subunits in their hemoglobin, which are the proteins in red blood cells that carry oxygen to the vital organs. Since coho and other salmon may have different forms of hemoglobin, oxygen transport in the blood is a good place to start this investigation, she said.

From there, the issues of blood chemistry get a little technical, but the ability of red blood cells to carry oxygen can depend not only on the form of hemoglobin but also on the pH (acidity) of the blood, she said, and that can be altered by drugs and other chemicals.

Another thing that researchers may be seeing is “disseminated intravascular coagulation,” a condition that results from clotting in the lining of the capillaries. DIC can reduce or block blood flow where it is most needed and eventually cause organ damage. That’s an area for more research, Jen said, noting that these investigations are moving forward in collaboration with researchers at NMFS and the U.S. Fish and Wildlife Service.

Meanwhile, Jen is working with chemists at the University of Washington’s Center for Urban Waters in Tacoma to figure out which substances — out of hundreds of chemicals found in stormwater — could be causing these deadly effects on fish.

If isolating the dangerous compounds proves too difficult, researchers might be able to start with the original toxic sources, perhaps exposing fish to chemicals found in tires, oil, antifreeze and so on, Jen said. For those effects, it might be good to begin the investigation with the well-studied zebrafish embryos, which are transparent and can be observed closely throughout their embryonic development.

Needless to say, this is a field of intense interest. If researchers can discover what is killing coho, they might begin to understand why the recovery of chinook salmon in Puget Sound has been so slow. Chinook, which could be added to Jen’s studies, are listed as a threatened species under the Endangered Species Act and are the preferred prey of Puget Sound’s killer whales, which are listed as endangered.

Two recent articles discussed the relative hardiness of the chum compared to coho salmon:

Struggle for clean water criteria coming to a close

The long-running controversy over Washington state’s water quality standards for toxic chemicals is nearly over. We will soon know just how pure the water must be to get a clean bill of health.

chinook

We still don’t know whether the Environmental Protection Agency will approve the new state standards adopted this week or impose more stringent standards that EPA developed for several key pollutants. The EPA has already taken public comments on its proposed standards.

“We believe our new rule is strong, yet reasonable,” said Maia Bellon, director of the Washington Department of Ecology, in a news release. “It sets standards that are protective and achievable. With this rule now complete, we will continue to press forward to reduce and eliminate toxics from every-day sources.”

For more than two years, much of the controversy focused on the fish-consumption rate — an assumption about how much fish that people eat. The FCR is a major factor in the equation used to set the concentration of chemicals allowed in water before the waterway is declared impaired. (See early discussions in Water Ways, Nov. 11, 2010.)

Initially, after plenty of debate, the state proposed increasing the FCR from 6.5 grams per day to 175 grams per day — a 27-fold increase. The initial proposal counter-balanced the effect somewhat by increasing the cancer-risk rate from one in a million to one in 100,000 — a 10-fold shift. Eventually, the state agreed to retain the one-in-a-million rate.

As I described in Water Ways last October, some key differences remain between the state and EPA proposals. Factors used by the EPA result in more stringent standards. The state also proposes a different approach for PCBs, mercury and arsenic, which are not easily controlled by regulating industrial facilities and sewage-treatment plants — the primary point sources of pollution.

PCB standards proposed by the EPA make representatives of industry and sewage-treatment systems very nervous. Water-quality standards are the starting points for placing legal limits on discharges, and EPA’s standard of 7.6 picograms per liter cannot be attained in many cases without much higher levels of treatment, experts say.

“Available data indicate that most state waters would not meet the EPA proposed criteria and that most (federally permitted) wastewater treatment plants will have to apply membrane filtration treatment and additional treatment technologies to address PCBs,” according to a letter from five industrial organizations and a dozen major businesses (PDF 3 mb).

Entities in Eastern Washington are in the midst of planning efforts to control pollution in the Spokane River, and major sewer upgrades are under consideration, the letter says.

“If Ecology were to follow the same approach on Puget Sound that it has on the Spokane River, this would amount to a range of compliance costs from nearly $6 billion to over $11 billion for just the major permits identified by EPA,” the letter continues. “A more stringent PCB criterion is also likely to impact how stormwater is managed, as PCB concentrations have been detected in stormwater throughout the state.”

For pulp and paper mills using recycled paper, the primary source of PCBs is the ink containing the toxic compounds at EPA-allowed concentrations, the letter says. Other major sources are neighborhoods, where PCBs are used in construction materials, and fish hatcheries, where PCBs come from fishmeal.

sailing

The letter points out similar problems for EPA’s proposed mercury standard, calling the level “overly conservative and unattainable in Washington (and the rest of the United States), as the levels of mercury in fish are consistently higher than the proposed criterion.”

When water-quality criteria cannot be attained for certain chemicals using existing water-treatment technology, facilities may be granted a variance or placed under a compliance schedule. Both environmentalists and facility owners have expressed concern over uncertainties about how the agencies might use these approaches.

Despite the uncertainties, environmentalists and Indian tribes in Washington state generally support the more stringent standards proposed by the EPA.

“Tribes concur that water quality discharge standards are only a part of the toxic chemical problem in the state of Washington and that more efforts toward source control and toxic cleanup are needed,” writes Lorraine Loomis of the Northwest Indian Fisheries Commission. “However, the standards are an essential anchor for determining where and how to deploy toxic reduction efforts and monitor enforcement.”

When I said this controversy is nearly over, I was referring to a time schedule imposed this week by U.S. District Judge Barbara Rothstein, who ruled that the EPA missed its own deadlines for updating water quality criteria.

Rothstein, responding to claims from five environmental groups, imposed a new deadline based on EPA’s own suggested dates. Because the state has finalized its rule, the EPA now has until Nov. 15 to either approve the state’s criteria or sign a notice imposing its own standards. Checkout the judge’s ruling (PDF 494 kb).

The new criteria won’t have any practical effect until applied to federal discharge permits for specific facilities or in developing cleanup plans for specific bodies of water — although state inspectors could use the new state criteria for enforcing state laws if they discover illegal discharges.

If you want to dig a little deeper, view the full list of comments about Ecology’s proposal, many of which refer to the alternate EPA proposal as well. Ecology posts its information on its “Water Quality Rulemaking” page. EPA posts its information on the “Washington Water Quality Standards” page.

Amusing Monday: Strange creatures and other ocean phenomena

Once in a while, a video shows up featuring some amazing phenomena not well known by most people. This is the case with a YouTube video by Mind Warehouse called “Ten Ocean Phenomena You Won’t Believe Actually Exist.”

I’ve featured several of the phenomena you’ll see in this video from my “Amusing Monday” series, but I admit that I did not know that some of these things even exist — and at least one photo appears to be a hoax that fooled the producers of the video on this page.

I’ve searched out a little more about each of the phenomena with links if you would like to learn more about any of these strange goings on.

Giant pyrosome

Thousands of self-cloned animals called tunicates occasionally come together to form a giant hollow tube that may grow to 60 feet long, according to Oceana’s Ocean Animal Encyclopedia. Giant pyrosomes are bioluminescent, producing their own light.

Because the tunicates can reproduce by cloning, the colony can regenerate its damaged parts to keep the tube intact. The tunicates that form pyrosomes are related to those found in the Salish Sea. Check out Emerald Diving’s tunicates page.

Megan Garber has written a story for The Atlantic, accompanied by a video, called “12 reasons pyrosomes are my new favorite terrifying sea creatures.”

Circles on the ocean bed

In 1995, divers discovered what looked like strange “crop circles” like those reported in farm fields, but these were on the ocean bottom near Japan. Other circles were found, but it took a decade before it was determined that male pufferfish make the circles as part of a mating ritual.

“When the circles are finished, females come to inspect them,” according to an article in LiveScience by Douglas Main. “If they like what they see, they reproduce with the males, said Hiroshi Kawase, the curator of the Coastal Branch of Natural History Museum and Institute in Chiba, Japan. But nobody knows exactly what the females are looking for in these circles or what traits they find desirable, Kawase told LiveScience.”

Striped icebergs

Most icebergs are white, but all sorts of blue-striped icebergs can be found in nature. They are the result of water filling a crevice and freezing so fast that no bubbles form. Green stripes form when algae-rich water freezes. Brown, yellow and black are the result of sediments being picked up by the water before it freezes. See undocumented photos and story by Mihai Andrei in ZME Science.

Red tide

Red tides can be found all over the world. Although “red tide” is a term often associated with poisonous plankton, many of the orange and red tides do not produce toxins harmful to people or marine life.

In Puget Sound, blooms of a dinoflagellate called Noctiluca sometimes create what appear to be works of art, as I described in Water Ways in June of 2013. Eyes Over Puget Sound, a program that monitors surface conditions, frequently presents pictures of colorful algae blooms, including a new edition published this morning.

Whirlpool

One of the strongest whirlpools in the world is at Saltstraumen, a fjord in Norway where a massive exchange of water rushes through an opening just 500 feet wide. Review the video “Deepest Hole in the Ocean.”

Brinicle

When salt-rich water streams into the sea, it can form an underwater finger of ice called a brinicle, sometimes referred to as “the ice finger of death.” The super-cooled briny water is colder than the surrounding sea, so the stream reaches out and freezes as it goes. See the article by Douglas Main in LiveScience or check out the blog post in Water Ways from November 2011.

Killer wave

When big waves come together at sea, the result is often a giant wave large enough to wreck an ocean-going ship or rush to shore with tremendous force. In January of this year, a killer wave — also known as a rogue wave — was recorded along the Pacific Coast in Grays Harbor County at a stream called Joe Creek. See Q-13 TV video “Rogue Wave …”

Frost flowers

When the air is considerably colder than a calm sea or lake, ice crystal can be extruded above the surface to form structures that resemble flowers. This occurs when water vapor sublimes from thin surface ice into the air without passing through the liquid phase. The warm moist air at the surface of the ice rises and quickly freezes in the colder air above.

Conditions leading to frost flowers often occur in the polar regions as new sea ice forms. Once the ice grows a little thicker, the surface cools down and the temperature difference between the ice and atmosphere are too close for the vapor to rise and then freeze.

Robert Krulwich, who hosted a science show for National Public Radio, discussed the phenomenon from the point of view of Jeff Bowman, a University of Washington graduate student in 2009 when he spotted frost flowers on his way back from an expedition to the Arctic.

Baltic and North sea meeting point

In the Mind Warehouse video, the narrator discusses a bunch of pictures purportedly showing the meeting point of the Baltic and North seas. I have been unable to track down all these photos or confirm that any of them were taken at the convergence zone of the Baltic and North seas.

One of the photos appears to have been taken in Alaska, showing the melt water from a glacier converging with ocean water. As in Puget Sound, the lower-density freshwater tends to form a layer over the salty seawater. See Kent Smith’s photo, taken from a cruise ship, and a story about research by the U.S. Geological Survey taken in the Gulf of Alaska.

It’s amusing to see all the myth-versus-fact posts on various Internet sites regarding the question of whether waters from the Baltic Sea actually mix with waters from the North Sea. (Search for “Baltic and North sea mixing.”) I gave up trying to find credible photos, but there exists an actual phenomenon regarding the mixing of the two seas. Wikipedia provides this explanation:

“The Baltic Sea flows out through the Danish straits; however, the flow is complex. A surface layer of brackish water discharges 940 km3 (230 cu mi) per year into the North Sea. Due to the difference in salinity, by salinity permeation principle, a sub-surface layer of more saline water moving in the opposite direction brings in 475 km3 (114 cu mi) per year. It mixes very slowly with the upper waters, resulting in a salinity gradient from top to bottom, with most of the salt water remaining below 40 to 70 m (130 to 230 ft) deep. The general circulation is anti-clockwise: northwards along its eastern boundary, and south along the western one.”

Bioluminescence

Living organisms can be seen to glow during a chemical reaction that involves a light-emitting pigment and an enzyme that serves as a catalyst for the reaction. Depending on the species, bioluminescence may be used to escape from prey, attract prey or signal for a mate. Sometimes researchers can’t tell why an animal has the ability to light up. One of the best write-ups I’ve seen is in Wikipedia.

Last fall, I featured in “Amusing Monday” a tiny creature called a sea sapphire that flashes brilliant hues of green, blue and purple then seems to disappear before your eyes. The organism is a copepod that is able to shift its plates to adjust the wavelength of light reflected from crystals underneath. When the reflected light is shifted far enough into the ultraviolet, the little animals nearly disappear.

Edith Widder, a specialist in bioluminescence, gives a fascinating TED talk on the subject in 2011. You can watch the video called “The Weird, Wonderful World of Bioluminescence,” in which she brings some glowing organisms to the stage.

Finding answers for dangerous decline of Puget Sound steelhead

Harbor seals have become prime suspects in the deaths of millions of young steelhead trout that die each year in Puget Sound, but the seals may not be working alone.

Trends

Disease and/or various environmental factors could play a part, perhaps weakening the young steelhead as they begin their migratory journey from the streams of Puget Sound out to the open ocean. Something similar is happening to steelhead on the Canadian side of the border in the Salish Sea.

More than 50 research projects are underway in Puget Sound and Georgia Strait to figure out why salmon runs are declining — and steelhead are a major focus of the effort. Unlike most migratory salmon, steelhead don’t hang around long in estuaries that can complicate the mortality investigation for some species.

The steelhead initiative was launched by the Washington Department of Fish and Wildlife and Puget Sound Partnership with funding from the Legislature. The steelhead work is part of the Salish Sea Marine Survival Project, which is halfway through its five-year term, according to Michael Schmidt of Long Live the Kings, which coordinates the effort in the U.S. The larger project involves at least 60 organizations, including state and federal agencies, Indian tribes and universities.

A new report on research findings for steelhead (PDF 9.8 mb) describes the most significant results to date for our official state fish, which was listed as “threatened” in 2007. While steelhead populations on the Washington Coast and Columbia River have rebounded somewhat since their lowest numbers in the 1980s, steelhead in the Salish Sea remain at historical lows — perhaps 10 percent of their previous average.

“Because steelhead are bigger and move fast through the system, they are easier to study (than other salmon species),” Michael told me. “It has been a lot easier to feel confident about what you are finding.”

Abundance

Steelhead can be imbedded with tiny acoustic transmitters, which allow them to be tracked by acoustic receivers along their migration routes to the ocean. It appears that the tagged fish survive their freshwater journey fairly well, but many soon disappear once they reach Puget Sound. The longer they travel, the more likely they are to perish before they leave the sound.

While steelhead are susceptible to being eaten by a few species of birds, their primary predators appear to be harbor seals. These findings are supported by a new study that placed acoustic receivers on seals and observed that some of the transmitters embedded in steelhead ended up where the seals hang out, suggesting that the fish were probably eaten.

In a different kind of tagging study, Canadian researchers placed smaller passive integrated transponder (PIT) tags in a large number of coho salmon and attached devices to read the PIT tags on coho salmon.

“What is most interesting to date,” states a new report from the Pacific Salmon Foundation,“ (PDF 4 mb), “is that we only have confirmed feeding on tagged coho salmon by four of the 20 seals equipped with receivers. This suggests that feeding on juvenile salmon may be an opportunistic behavior acquired by a limited number of seals.”

New studies are underway to confirm steelhead predation by looking at fecal samples from seals in South Puget Sound. Researchers hope to figure out what the seals are eating and estimate steelhead consumption.

As I mentioned at the outset of this blog post, it may be more than a simple case of seals eating steelhead. For one thing, seal populations may have increased while their other food choices have decreased. Would the seals be eating as many steelhead if Puget Sound herring populations were close to their historical averages?

Other factors may be making young steelhead vulnerable to predation. A leading candidate is a parasite called Nanophyetus salmincola, which can infest steelhead and perhaps increase their risk of predation. The parasite’s life cycle requires a snail and a warm-blooded animal, as I described in a story I wrote for the Encyclopedia of Puget Sound — part of a larger piece about disease as a powerful ecological force. Anyway, the snail is found only in streams in South Puget Sound, which might help explain why steelhead deaths are higher among these South Sound populations.

Experiments are underway to compare the survival of two groups of identical steelhead, one group infested with Nanophyetus and one not.

Depending on funding and proper design, another experiment could test whether treating a stream to temporarily eliminate the snail — an intermediate host — could increase the survival of steelhead. If successful, treating streams to remove these snails could be one way of helping the steelhead. For these and other approved and proposed studies, check out the Marine Survival Project’s “2015-2017 Research Work Plan” (PDF 9.3 mb).

Other factors under review that could play a role in steelhead survival are warming temperatures and pollution in Puget Sound, which could help determine the amount and type of plankton available for steelhead and salmon. Could a shift in plankton result in less food for the small fish? It’s a major question to be answered.

I’ve mentioned in Water Ways (3/15/2010) that transient killer whales, which eat seals, sea lions and harbor porpoises, may be helping their distant cousins, the Southern Resident killer whales, which eat fish. Those smaller marine mammals compete for the adult salmon eaten by the Southern Residents. By clearing out some of those competitors, the transients could be leaving more salmon for the Southern Residents.

It may be too early to draw any firm conclusions, Michael Schmidt told me, but transient killer whales may be helping steelhead as well. Last year, when transients ventured into South Puget Sound and stayed longer than usual, the survival rate for steelhead from the nearby Nisqually River was the highest it has been in a long time.

Were the whales eating enough seals to make a difference for steelhead, or were the seals hiding out and not eating while the whales were around. Whether there were benefits for the steelhead, we could be seeing what happens when a major predator (orcas) encounters an abundance of prey (seals).