Washington's heat wave has marine scientists keeping a close eye on Puget Sound

TACOMA, Wash. - As Washington residents flocked to beaches during this week's heat, a very different scene was unfolding beneath the surface of Puget Sound.

Twice a week this summer, divers from the Point Defiance Zoo & Aquarium have been surveying bull kelp forests off Owen Beach in Tacoma, documenting the underwater ecosystem and tracking changes from year to year as part of a broader statewide effort to restore 10,000 acres of underwater forest by 2040.

"It's like descending through the canopy of a rainforest that you would see in the tropics," said Adam Schare, a diver helping lead the project.

Once underwater, Schare says the towering kelp can be so dense that "you're picking your way through it like you're walking through a bramble of blackberries."

For Schare, the work is as inspiring as it is important.

"The ocean will humble you and makes you feel small. In the most magical way," he said.

But the surveys are also documenting a sobering reality. The Washington State Department Natural Resources reports Puget Sound has lost about 80% of these underwater forests over the past century, making annual monitoring increasingly important.

Divers document what's happening below the surface

Each survey begins with a boat ride into Commencement Bay before Schare and dive partner Elisabeth descend beneath the surface.

Because they can't speak underwater, the pair communicate using waterproof notepads while following a 30-meter transect tape to stay together and measure their survey area.

During a roughly 60-minute dive, they're documenting eight different species of kelp, the types of seafloor where they grow and the marine life living among them.

Warm water is adding stress to kelp

During the FOX 13 dive, Schare recorded a water temperature of 55 degrees Fahrenheit at a depth of 39 feet.

"During the winter that's even considered pretty high," he said. "To see that tens of feet underwater in the summer is quite alarming."

He said rising surface temperatures are putting additional stress on bull kelp, which thrives in cooler water, generally in the upper 40s to low 50s Fahrenheit.

He also said changing nutrient loads flowing from the Puyallup River are another factor affecting kelp in Commencement Bay.

Why bull kelp matters

Schare says bull kelp provides critical habitat for salmon and other marine species while also helping absorb carbon dioxide, reducing the effects of ocean acidification.

"They are critical for the salmon fisheries," he said.

Bull kelp is an annual species that begins growing in the spring, reaches its peak during the summer and typically dies back by October or November.

"We're intrinsically connected to these kelp forests whether you know it or not," said Schare.

As divers continue their surveys throughout the summer, Schare hopes their work helps people better understand the ecosystem hidden beneath Puget Sound's surface.

His goal, he said, is to "put light on the very dark, emerald waters that we have below us."

MORE NEWS FROM FOX 13 SEATTLE

UW report says Washington driver data was used in 58 immigration arrests

3 women injured in North Seattle shooting

Teens do $50K in damage to WA Air Force veteran's vacant home

WA health expert explains cyclosporiasis symptoms, safe food practices

Seattle Aurora Avenue sweep: Multiple arrested, victims rescued

Here's where fires in Washington state are burning

To get the best local news, weather and sports in Seattle for free, sign up for the daily FOX Seattle Newsletter.

Download the free FOX LOCAL app for mobile in the Apple App Store or Google Play Store for live Seattle news, top stories, weather updates and more local and national news.

EnvironmentWashingtonTacomaNews