Elwha River

The Algae “Strike Back”: Post Dam Removal Benthic Surveys at the Elwha River Mouth

By Sean Sheldrake, Steve Rubin, and Rob Pedersen

EPA science diver photographs kelp samples on board boat.

EPA diver Rob Pedersen photographs samples.

Some of you may have followed our previous blog posts about EPA’s scientific diving program, including 2011 and 2012 reports from the Elwha River mouth in the Strait of Juan de Fuca.

The field site is downstream from the largest dam removal and restoration project to date, a large scale effort to restore wild salmon habitat and other aspects of the natural ecosystem. (For a great overview of the project, check out the webinar series posted by Olympic National Park.)

In this 2013 installment, we share some interesting findings about our benthic survey on how the dam removal is affecting things at the mouth of the river.

This survey involves counting 72 species of invertebrates and 13 species of algae—all of which are experiencing changes, some dramatic, as a result of the largest dam removal and restoration project to date: an experiment of grand scale for Elwha River mouth seafloor residents!  The survey is led by the U.S. Geologic Survey, and the team includes Washington Sea Grant, the Lower Elwha Klallam Tribe, and EPA divers.

Stationary light sensor placed near the Elwha River mouth.

Stationary light sensor placed near the Elwha River mouth.

Although divers reported seeing fewer algae, the scientists are still crunching the numbers. Early indications suggest a decrease in algae abundance, including the famed, forest-forming “bull kelp” since the removal of the dam. These changes may be due to decreased light levels, a loss of suitable substrate (a growing surface like a rock of some size, or even as small as gravel), or a combination of the two.  The team of divers used light sensors at many stations to help to document whether changes in light penetration were occurring at the dive sites to supplement quantitative data about the changes in the seafloor substrate.

In addition, it seems that tubeworms are on the increase in some areas.

This year, early reports indicate a late growing season for algae, perhaps due to the “silt cloud” hanging over areas near the river mouth. A few surprises may be in the works, too, such as the appearance of the rare kelp species pictured below, a sample the team of scientific divers could not immediately identify underwater—a discovery suggesting that as algae are faced with reduced light levels, a species or two not found during previous surveys might be trying to join the party.

Diver holds kelp sample underwater.

Mystery kelp.

Early suspicions from USGS and other experts narrowed down the mystery alga to either Laminaria ephemera or Laminaria yezoensis, and follow up examination confirmed it to be Laminaria ephemera. The unfolding story was covered in the local Peninsula Daily News.

To answer a few questions you might be wondering about all this:

  • Why does algae matter?
    Answer: Well it’s quite a nursery for young marine life and a grocery store for young and old that live in the sea.  It’s not unusual to see gray whales and their young grazing in the ‘kelp forest.’ Changes for shellfish are also of great importance to local fisheries.  The river is connected to the ocean in so many ways—and the silt keeps coming!
  • What other changes are there?
    Answer: The ongoing study will show changes for nearly 100 species of algae and invertebrates, in addition to fish, for the largest dam removal effort in North America to date.

For more information on the USGS-led study, see: http://www.usgs.gov/elwha, http://pubs.usgs.gov/sir/2011/5120/seaLife/.  For a full set of 2013 photographs, see: Elwha 2013.

Read more about the latest in EPA scientific diving at facebook.com/EPADivers.

About the AuthorsSean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon.  Sean Sheldrake serves on the EPA diving safety board, responsible for setting EPA diving policy requirements, where Rob Pedersen has served for many years.  In addition, they both work to share contaminated water diving expertise with first responders and others.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Diving the wilds of the Strait of Juan de Fuca; should we stay or should we go?

By Sean Sheldrake, Steve Rubin, and Alan Humphrey 

EPA Survey Crew: from left, Rob Pedersen, Alan Humphrey, Scott Grossman, and Sean Sheldrake.

Survey crew, from the left: Rob Pedersen, Alan Humphrey, Scott Grossman, Sean Sheldrake.

Some of you may have followed our previous blog posts about EPA’s scientific diving program, including part two of the Elwha River story.   

In this third and final part of our story, we return to the Elwha River to talk more about the challenges involved with the survey of invertebrates and algae. 

Between the divers and the boat operator aboard the EPA Monitor (our 30-foot research vessel), we’ve got over a century of boating experience, but making safe boating decisions is by no means easy.  We’ve got a big job to do in collecting data on this first survey after the largest dam removal in North American history.  The total amount of sediment behind the dam is 19 million cubic meters, enough to fill the stadium of the Seattle Sounders Football Club, eight times.   USGS estimates indicate ¼ to ½ of this material could be transported from the former reservoir areas, eventually finding its way to the coast.  The survey will evaluate the impact on the ocean seafloor. 

However, while conducting the survey at the meeting place of the Olympic peninsula and the wild waters of the Strait of Juan de Fuca, we’ve got to stay safe. 

While doing our work, small craft advisories were issued alerting vessels in our class that danger may be approaching.  Would rough seas really hit our boat, or our area, making it treacherous to retrieve divers from the water? 

EPA Boat Captain Doc Thompson. (Photo by Alan Humphrey)

Doc Thompson, a veteran boat operator for EPA, tells our crew, “That’s it boys: it’s blowing too hard out here.”  Doc is an understated fellow—we all know that when he’s concerned, WE’RE concerned.  Out of the clear blue, gale force winds popped up.  We recall the divers and secure our gear to get back to port as soon as possible! 

When over 40 years of boating experience tells Doc it’s time to go, it’s time to get back to port.  But we were back to finishing our survey the next day.  As budgets allow, we’ll be back in 2013 to evaluate the next phase of sediment release from the mighty Elwha River into the Strait of Juan de Fuca. 

For more information on the USGS led study, see: http://www.usgs.gov/elwha

Read more about the latest in EPA scientific diving at facebook.com/EPADivers [http://www.facebook.com/EPADivers]. 

About the authors:  Sean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon.  Sean Sheldrake and Alan Humphrey both serve on the EPA diving safety board, responsible for setting EPA diving policy requirements.  In addition, they both work to share contaminated water diving expertise with first responders and others.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

What’s changed? Post dam removal benthic surveys start at the mouth of the Elwha River

By Sean Sheldrake, Steve Rubin, and Alan Humphrey

Tube worms

Schizobranchia insignis tubeworms, Photo by Sean Sheldrake, USEPA.

In this second part of our story (see our earlier blog post), we return to the Elwha to talk more about the techniques involved with the survey.

This USGS-led survey involves counting over 65 species of invertebrates and 23 species of algae—all of which we had to memorize before the survey began.  As if that wasn’t enough homework for the dive crews, you have to “sneak” up on your critters to actually count them!

Species like Mya truncata clams can “see” you coming and will retract if they can feel the pressure wave of the diver approaching.  Likewise, tubeworms are also underwater detectives with their own early warning sensors for approaching divers.  Once Schizobranchia insignis or Eudistylia polymorpha tubeworms retract they look remarkably similar!

In buddy teams, divers go down and count algae (kelp, for example) on one side of the transect, and invertebrates (such as clams) on the other.  Our divers must adjust for this “shy” behavior when they reach the bottom and “change things up.”   Since each diver must count critters and algae on one side of the transect only, the invertebrate scientist tries to count on the downcurrent side of the transect line.  After all, the algae-counting scientist has the benefit of their “prey” not running away from them!

Diver along a transect

EPA diver Scott Grossman conducts a uniform point count along a straight line "transect" placed on the ocean floor. Photo by Alan Humphrey, USEPA.

In addition to counting all the species within one meter of the transect tape for 30 meters for algae and invertebrates respectively, a separate survey is done called a “uniform point count.”  Every ½ meter, the diver puts their finger down along the transect tape and counts only what is beneath it. (Even if the most amazing anemone is an inch away, it doesn’t count!) Statistically, the point count and overall tally of species will give a representative assessment of life in the ocean ecosystem near the Elwha River mouth.

Early survey results included a decrease in algae abundance compared to levels seen before the start of dam removal.  The decrease may have been due to light deprivation rather than loss of suitable substrate as there was little obvious accumulation of sand or mud on the seafloor.  The divers deployed light sensors at many stations to help to document what sort of change in light penetration was occurring at each site.  In addition, it seems that tubeworms are on the increase.

What other changes are there?  The study will show the changes for the nearly 100 species of algae and invertebrates, in addition to fish, for the largest dam removal effort in North America to date.

Find out more about the wild survey conditions next week in part three of our story.

For more information on the study, see: http://www.usgs.gov/elwha.

For more information about the EPA dive program, check out their Facebook page at: http://www.facebook.com/EPADivers.

About the authors: Sean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon.  He and Alan Humphrey both serve on the EPA diving safety board, responsible for setting EPA diving policy requirements.  In addition, they both work to share contaminated water diving expertise with first responders and others.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

Diving in the Silt Plume of the Elwha River

By Chad Schulze, Steve Rubin, and Sean Sheldrake

Mouth of the Elwha River

Overlooking the mouth of the Elwha River.

Some of you may have followed our previous blog posts about EPA’s scientific diving program in It’s Our Environment, but we also wanted to share some recent work led by U.S. Geological Survey (USGS) and supported by EPA divers near the mouth of Washington State’s Elwha River here in It All Starts with Science.

Now that removal of the Elwha River dams is well under way, USGS scientists, assisted by divers with the Lower Elwha Klallam Tribe, EPA, and Washington Sea Grant, will continue studying the impacts of removal-related sediment to the Strait of Juan de Fuca.

As the first EPA crew to visit the site this year, we didn’t know what to expect.

What we did know—the removal of the Elwha River dams will affect marine habitats in the Strait of Juan de Fuca, primarily from the flow and deposition of released sediment that had accumulated behind the dams for nearly 100 years. That sediment can affect marine life in many ways, including: burial, reduced aquatic reproduction, shading and light reduction, damage to animal gills and filter feeding structures, and changing how different species behave individually and together with their different tolerances and responses to the sediment.

EPA Scientific Diver

Diver Steve Rubin, USGS shooting video of a transect to compare to baseline conditions.

Diving in on the first day, we found the conditions to be very different from before the dams were in place—last year visibility might be up to 50 feet!  Not so this year, with some freshwater layers discharging from the Elwha with maybe 6 inches of visibility.

As we descended through this floating “halocline” of different salinity layers (less dense freshwater will sometimes float over the ocean saltwater until it mixes), it was like a “cloud” over the saltwater below.  Visibility improved when we made it through, but it was DARK.  Where last year the sun was sometimes visible on the seafloor, this year, we needed lights to see the bottom.

Things have changed. For starters, where there had been algal forests, we found much less growth compared to last year. We and our partners will continue to survey Elwha nearshore undersea communities during and after dam removal.  Measuring responses to short and long term changes in deposited and suspended sediments offers an unprecedented opportunity to gain insight relevant to managing these important marine resources, and will help to inform how future dam removal projects can be conducted to minimize impact to downstream plants, insects, fish and animals.

For more information on the study, please see this story on the USGS web site: http://walrus.wr.usgs.gov/elwha/

We’ll follow up with another post as we continue to work. Stay tuned!

About the authors:  Sean Sheldrake and Chad Schulze are part of the Seattle EPA Dive unit.  Chad is the lead pesticide enforcement in the Northwest, and Sean is also a project manager working on the Portland Harbor cleanup in Oregon.  Steve Rubin is an aquatic biologist specializing in algal species with the USGS and a lead scientist on the survey.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.