Nerdy Science Archives - Seattle Aquarium

Hidden science superheroes: Meet the Seattle Aquarium’s water quality team

Posted on November 21, 2023June 17, 2024 by Emma Leiser

This story is part of our Nerdy Science Series—how we’re using research and technology in service of a healthy ocean.

From basket stars to fur seals, what do all animals at the Seattle Aquarium have in common? They need just the right conditions in their water to flourish. The mission of maintaining the Aquarium’s water quality every minute of every day is undertaken by a small but skilled group of chemists using both new technology and ancient solutions.

Water Quality Manager Hannah Mewhirter says her team is usually the first to notice when there’s a problem with a habitat’s water. That’s mainly because many water quality issues don’t change the water’s appearance.

The team tests 20–40 water samples from the main Aquarium and offsite Animal Care Center each day. They check several physical properties of the water like salinity, pH levels, dissolved oxygen levels and temperature. And they test for nutrients like ammonia, nitrate, nitrite and phosphate. All these parameters need to be balanced for aquatic animals to thrive.

The team also collects daily data, which helps them identify changes and guides their actions. When they notice an imbalance, they work with members of the engineering team and animal care teams to identify what caused the issue and how to amend it.

“It’s a collaborative process,” Hannah says. “We tell the animal care teams what their water quality looks like. They tell us what they need for their animals, and we work together. It’s like creating a customized plan.”

Many species at the Aquarium are from the Puget Sound region. To accommodate them, the Aquarium brings in seawater from Elliott Bay. After a little filtration and supplementation, this water is pumped into our animal habitats. We then filter and return the water back into Puget Sound.

Although seawater looks like an unlimited resource, it’s not. We want to be the best stewards of that seawater because it is the lifeblood of the Seattle Aquarium.

Hannah Mewhirter

Water Quality Manager, Seattle Aquarium

Ocean Pavilion brings changes

The Ocean Pavilion—which opens in 2024 and will feature tropical plants, fish and invertebrates from the Coral Triangle region of the Pacific Ocean—uses a different system. It’s designed to clean and recirculate 96% of the salt water in its habitats, saving both water and energy. Recaptured heat from the warm water will also help heat the building.

“The Seattle Aquarium has embraced a paradigm shift,” Hannah says. “Water quality is far more complex and sensitive in a closed-mode aquarium than in an open-flow aquarium. That will require daily testing and looking at more parameters because we are intentional about reusing the water.”

Innovative technology helps the team stay on top of water quality testing. One tool that Hannah is particularly excited about is the ion chromatograph, which tests nine different chemical properties at once. The tool not only cuts down on the time, energy and chemical reagents needed to conduct those individual tests but also reduces the amount of plastic packaging.

“Ammonia is one of the most sensitive parameters we test,” Hannah says. “We’re never going to miss ammonia testing. If anything, we’re going to add ammonia testing, especially in a fully recirculating water system. But thinking of doing that while adding environmental costs with all that plastic—it just didn’t sit well with me. So, we’re going to pursue a greener method using an ion-selective electrode.”

These sustainable choices also align with the Aquarium’s goal of becoming a zero-waste operating facility by 2025.

Finding solutions

The most powerful tool the team uses to keep water clean is low-tech but no less meticulous: bacteria.

When animals eat food, they convert some of it into energy and the rest into waste products, which contain a lot of nitrogen. In large quantities, nitrogen could create harmful conditions.

Nitrifying bacteria break down the nitrogen-rich waste products and help balance the chemistry in animal habitats. These bacteria create their own waste that other bacteria eat in turn, creating a sustainable cycle. The water quality team monitors the bacterial population to create a biological filtration system that maintains water quality 24/7.

Hannah sees her work as a puzzle with many pieces. Chemistry, creativity and collaboration help Hannah and her team keep the Aquarium’s water in the clear.

“Things are relatively stable from day to day—and we want them to be. But when they’re not, that is a challenge that brings out the joy of problem-solving. I like figuring out what has changed and collaborating on how we need to fix it,” Hannah says.

She sees sea otters by the nearshore: Tracking sea otter populations with Dr. Shawn Larson

Posted on September 27, 2023June 17, 2024 by Emma Leiser

This story is part of our Nerdy Science Series—how we’re using research and technology in service of a healthy ocean.

Guests at the Seattle Aquarium know how fun it is to watch sea otters eat and play. But for sea otter researchers, watching these adorable animals on Washington’s outer coast also provides valuable scientific information. By keeping track of wild sea otter populations through regular surveys, Dr. Shawn Larson of the Seattle Aquarium and her team hope to better understand the important role otters play in the marine ecosystem and what the future might hold for them.

Searching for sea otters on Washington’s outer coast

Each June for the past 23 years, Seattle Aquarium researchers have participated in a statewide, multiday survey of the Washington sea otter population, organized by the U.S. Fish and Wildlife Service and the Washington State Department of Fish and Wildlife.

Shawn and other Seattle Aquarium staff assist by forming ground teams at specific locations along the coast to carefully count all the otters in an area. The team usually leaves bright and early to hike to the observation point, where they set up their spotting scopes and start looking for otters.

They also record information on the otters’ ages and behaviors. During the survey, a plane circles above large groups of otters—known as rafts—to take high-quality digital photographs. Researchers count the otters in these photos later.

The otters tend to float about a kilometer (a little over half a mile) from the shore in groups of up to 1,000. It can be hard, at that distance, to distinguish rafts from clumps of kelp floating nearby. But Shawn, a seasoned otter spotter, knows to look for heads and flippers. Otters also tend to appear black, while kelp looks dark brown.

The Seattle Aquarium also does surveys of the local population monthly, documenting their numbers and diets. Like us, otters have preferred foods. If they’re available, otters will go for sea urchins, crabs and clams. When those become scarce, otters will turn to snails, mussels and sea cucumbers. Shawn has even seen otters eat a giant Pacific octopus!

“Their diet starts to diversify…and that’s when we know that their population has pretty much reached its carrying capacity—meaning the limit for that area,” Shawn says.

Happily, the sea otters in Washington are doing well. Their population is steadily growing with an increase of about 10% each year. They’re growing large and raising many pups, suggesting that these days, there’s plenty of their favorite foods on the outer coast.

Scientists still have a lot of questions about sea otters

Despite decades of research, scientists are still uncovering new information about sea otters. We know that otters eat sea urchins that would otherwise consume kelp. So, where there are otters, there are usually also healthy kelp forests, which serve as habitats for an array of nearshore marine life. However, researchers seek a deeper understanding of how sea otters impact nearshore environments.

"They're kind of a mystery in a lot of ways. There's a lot we do know about them, but there's a lot we don’t."

Dr. Shawn Larson, senior conservation research manager, Seattle Aquarium

“We know that sea otters tend to structure the nearshore where they live, but exactly how does that work? What are the pieces of the puzzle that make it work?” Shawn says.

To unravel the mystery, the Aquarium is in the early stages of using a remotely operated vehicle, or ROV, to study otter foraging behavior in kelp forests on the outer coast. By going underwater to where the action is, the ROV will provide in-depth footage and data on sea otter foraging behavior.

A better understanding of sea otters and kelp can’t come soon enough. Kelp is highly effective at sequestering carbon, which could help offset some effects of climate change.

"I hope that we continue to do this work for decades to come… The food sea otters are able to catch really will show how they are able to adapt or not to oceanic changes."

Dr. Shawn Larson, senior conservation research manager, Seattle Aquarium

Another question researchers are exploring is how sea otters will react to climate change.

With up to 1 million hairs per square inch, their dense coats keep them warm in the chilly waters of the Pacific. But otters have trouble expelling heat. Rising ocean temperatures could push them farther north. At the same time, otters tend to thrive in nearshore environments. Rising sea levels and melting sea ice could provide more habitat for them.

“We just don’t know. There could be dramatic negatives with climate change for sea otters and there could be dramatic positives,” Shawn says.

How to help sea otters in the wild

One thing we do know is that sea otters need a clean home. Trash that ends up in the sea can reach them via ocean currents. By properly disposing of trash, you can help keep the ocean clean for sea otters and other marine life.

Consider reducing plastic consumption and choosing reusable options when you can. Better yet, volunteer at a beach cleanup to remove plastic and other trash from our shores. You can even get your friends involved!

For more ways to help the ocean and all that depend on it (including humans!) check out our Act for the Ocean page.

How can we stop sharks from going extinct?

Posted on August 15, 2023June 17, 2024 by Emma Leiser

This story is part of our Nerdy Science Series—how we’re using research and technology in service of a healthy ocean.

Sharks have roamed the ocean since before dinosaurs walked the earth. But today, around a third of the world’s 500+ shark species are threatened with extinction. New research co-authored by Riley Pollom of the Seattle Aquarium offers a way forward.

Why are sharks going extinct?

In a word: overfishing. Fishing—legal and illegal—kills around 100 million sharks every year. Sharks are targeted as sources of food and products; they’re also caught as bycatch in the hunt for other species. Because sharks take longer on average than other ocean animals to mature and reproduce, their populations often don’t recover quickly. Sometimes they don’t come back at all.

When shark species go extinct, the loss has a ripple effect. Ocean food webs are delicate, and the disappearance of a major predator can wreak havoc, sometimes causing the populations of other animals in the system to swell or shrink in unpredictable ways. The impact of these big changes often falls on coastal communities who rely on small-scale fishing for food and income. But as we lose species at an unprecedented rate, all of us will be affected.

Aquariums have the knowledge and capacity to play an important role in population management when things get dire. There’s a point of no return, and we need to avoid it.

Riley Pollom, species recovery program manager, Seattle Aquarium

A clue on how to turn the tide

A team of researchers that included Riley analyzed shark populations throughout the Western Atlantic Ocean over decades.

The team’s newest paper, “Conservation successes and challenges for wide-ranging sharks and rays,” focuses on 26 wide-ranging coastal sharks and rays in the Western Atlantic. All are on the IUCN Red List of Threatened Species. For decades, the Western Atlantic has faced a heavy demand for fishing. And sharks there have suffered, often as bycatch in the industry.

But—as the research team found—sharks in the Northwest and Western Central Atlantic are now making a comeback. In fact, some species that were on the verge of collapse in the 1980s and 1990s are now at stable or even growing populations.

Meanwhile, the situation is very different in the Southwest Atlantic. There, almost all populations of shark species—including many of the same species that are recovering in other regions—are still in trouble.

What’s fueled the difference? The answer, researchers found, is strong fisheries management.

Fisheries management refers to setting, enforcing and monitoring strict limits on how many animals can be caught, where and when they can be caught, and other important rules. Where these practices are robust, like the Northwest and Western Central Atlantic, shark and ray populations are rebounding. Where they are weak or nonexistent, many species are on the verge of extinction or heading that way.

“If strong fisheries management measures are implemented elsewhere, we would expect to see similar recovery,” Riley says.

Avoiding the extinction vortex

As the new research shows, protective measures work. But in some cases, those measures aren’t enough.

In a situation that conservationists call the “extinction vortex,” the population of an endangered species drops so low that even if other threats are removed, the species will not recover and may still go extinct. That’s because when populations are small enough, males and females have trouble finding each other. Those that do risk inbreeding, introducing genetic defects and weakening fitness.

In some cases, direct intervention by people might be the only way to avoid the extinction vortex. Increasingly, aquariums are getting involved in this work.

In 2020, the Seattle Aquarium helped launch ReShark—a global collective to recover threatened shark and ray species. ReShark’s first project is to breed and release Indo-Pacific leopard sharks, which have all but vanished from their home waters off the coast of Raja Ampat, Indonesia. Projects like this are still novel for aquariums—but so far, ReShark has had early success rearing shark eggs born in aquariums for release into their marine-protected home waters. (Read National Geographic’s coverage.)

As species recovery program manager, Riley is helping to lead the Aquarium’s growing programs and partnerships to bring back threatened species in Washington State and internationally.

What can individuals do?

Wherever you live, “Vote with the ocean in mind,” Riley says. “Learn and understand politicians’ stances on ocean policies and fisheries management policies.” When we’re informed, we can advocate for setting and enforcing strong fisheries management. Join the Aquarium’s email list to receive alerts on how you can support our state and federal advocacy on behalf of the ocean.

Hawai’i is facing more marine heatwaves. What does that mean for its fish?

Posted on July 28, 2023June 17, 2024 by Emma Leiser

This story is part of our Nerdy Science Series—how we’re using research and technology in service of a healthy ocean.

During 2014, a mass of warm water nicknamed “the blob” simmered and spread in the Pacific Ocean. It lingered until early 2016, wreaking havoc on marine ecosystems and causing a mass coral bleaching event in Hawaiʻi’. Then in 2019, another marine heat wave struck Hawaiʻi, reminiscent of the blob. Smaller heatwaves have followed.

Seattle Aquarium research technician Amy Olsen was born and raised on Hawaiʻi’s Big Island. Rising ocean temperatures, which most scientists attribute to climate change, are transforming her home. Today, as a marine scientist for the Aquarium, Amy is leading scientific papers that analyze how those changes are affecting fish populations off the Big Island’s coast.

"By 2025, marine heatwaves are likely to occur every year. There is an urgent need to see what’s happening now and how we can anticipate and mitigate those changes."

Amy Olsen, research technician, Seattle Aquarium

Working Far Beyond our Walls

For nearly 40 years, Hawaiʻi ecosystems have been part of the Seattle Aquarium experience. If you’ve visited the Aquarium, you’ve likely marveled at Pacific Coral Reef, a lush community of corals, puffers, tangs, wrasses and other members of tropical reefs.

But what isn’t visible to Aquarium visitors is the scientific research that takes place outside its walls. Since 2009, Aquarium researchers have traveled to Hawaiʻi and donned scuba gear to track fish populations in eight locations off the west coast of the Big Island.

Their goal: to provide long-term data on the health of fish populations.

Connecting Research and Home

“This research is a way to give back to the place where I was raised,” Amy says.

She joined the Aquarium’s Hawaiʻi research team in 2014, the same year the blob struck. She later decided to focus her master’s thesis on how marine heat waves affected groups of fish, using Aquarium data gathered between 2009 and 2019.

Amy works closely with Dr. Shawn Larson, senior conservation research manager—who launched the Aquarium’s Hawaiʻi research—and a multidisciplinary Aquarium team that includes conservation researchers, dive experts and scientists who specialize in fish and invertebrates.

The team uses a unique method to measure fish populations each year. It’s the same method we’ve used to monitor local Salish Sea fish populations for decades. Researchers dive along defined 100-meter sections (transects) of the ocean while wearing underwater cameras. As they swim along a transect, they speak into a microphone, narrating the species and number of fish in their line of sight and creating a recording that can be analyzed later. The team uses GPS coordinates and visual notes to return to the same spots year after year without leaving behind physical markers that could impact marine life.

This method proved so efficient in the Aquarium’s Hawaiʻi research—where divers often had more than 100 species in sight—that the team published a special methods paper to share it with other researchers.

Troubled Findings and a Call to Action

Amy’s thesis—published in the journal Marine Ecology Progress Series last year—analyzed changes in different subgroups of fish following the heatwaves.

The groups included predators, “secondary consumers” (typically small fish that eat other fish or plants), planktivores (animals that eat plankton), corallivores (animals that eat coral), browsers (which eat algae), grazers (which eat short, fibrous turf algae) and scrapers (which effectively clear algae from corals). Why so many groups? Each plays a unique role in their delicate food web.

The research showed that after the 2014–2015 heat wave, fish populations in all groups increased. The group that grew the most were the grazers, tiny fish that eat turf algae.

“One hypothesis is that the heat wave encouraged more algae to grow,” Amy explains. “Fish that graze on it did well because they had more food.”

But any change to ocean food webs is complex. The same warming events that benefitted fish are devastating coral. The breakdown of coral will mean less food for the creatures that eat coral and fewer hiding spots for larger fish. The bottom line: Pulling a thread in ocean food webs can unravel the entire sweater.

My goal is that our scientific partners use this research to inform decision-making and policy. For individuals, I hope it encourages curiosity, behavior change and hope—because our actions do make a difference.

Amy Olsen, research technician, Seattle Aquarium

What can individuals do to help slow marine heatwaves and protect reefs?

A lot, Amy says. One simple action is to use reef-safe sunscreen, whether we’re swimming in Pacific Northwest or tropical waters. Coral reefs exist in both. With this small step, we can do less harm to wild populations of coral, which are already stressed.

Climate change remains one of the biggest challenges we and the ocean face. Shifting our day-to-day habits—from how much we drive to what we eat—matters. So does large-scale policy change. The Aquarium advocates for policies that address climate change and protect our ocean. Get involved by learning more and signing up for Seattle Aquarium action alerts.

AI goes below the surface: Using technology to make a difference for local kelp

Posted on April 19, 2023June 17, 2024 by Emma Leiser

This story is part of our Nerdy Science Series—how we’re using research and technology in service of a healthy ocean.

On Saturday, April 22, 2023, Xbox and the Seattle Aquarium joined together for a live Earth Day celebration, including a demonstration of our remotely operated vehicle, Nereo!

Kelp forests are critical for ecosystem health. They provide food and habitat for marine species of all kinds, including endangered salmon and southern resident orcas. They also sequester carbon, mitigating the effects of ocean acidification. (Watch The Kelp Highway to learn more about the importance of kelp forests in the Salish Sea.)

Bull kelp forms the “trees” in these underwater forests. It attaches to hard surfaces on the seafloor and grows with incredible speed: up to 2 feet per day, reaching lengths of up to 100 feet in a single season.

But that’s if it’s growing. Once abundant throughout the Salish Sea, kelp forests have declined drastically over the past several decades, with a reported 60% overall loss of bull kelp in our local waters since 1980, and up to 95% in some areas.

What’s puzzling researchers, though, is that kelp forests continue to thrive in parts of the Salish Sea, including sections of Elliott Bay along Seattle’s urban waterfront (and directly below the Aquarium’s pier).

Partnering with the Port of Seattle to Learn More

Now the Seattle Aquarium is partnering with the Port of Seattle to study kelp forests in Elliott Bay using a remotely operated vehicle, or ROV, which we’ve fondly named ROV Nereo—short for Nereocystis luetkeana, the scientific name for bull kelp.

Research of this kind has typically been undertaken with scientific scuba divers doing surveys below the surface or via satellite imagery captured from far above. Both methods have their drawbacks: while divers can observe many species along the seafloor, they’re limited by the amount of gas they can carry on their backs and, ultimately, can’t cover much ground. Satellites, of course, can cover much larger areas—but aren’t able to capture kelp that hasn’t reached the water’s surface, or other species that live below it.

Enter the ROV. The compact ROV, that is. Historically, these machines have been large, bulky and expensive, and deployed from large vessels to explore deep water, which isn’t what’s needed to study kelp forests in relatively shallow depths.

ROV Nereo from Blue Robotics is small, relatively inexpensive, customizable and maneuverable—all critically important features when navigating long ropes of kelp and floating fronds. With cameras facing forward and downward, lights and sensor equipment, it can capture images of more species over a larger area than a scientific diver. ROV Nereo is easy to deploy and pilot, and equipped with sonar—so it will stay at a consistent altitude above seafloor—as well as GPS to track real-time positioning. All that, and it’s operated with an Xbox controller! You can learn more about the ROV and see video taken along the seafloor on the ROV development GitHub.

Kelp Conservation Meets Artificial Intelligence

Since the summer of 2022, led by the Aquarium’s Research Scientist Dr. Zachary Randell, we’ve been using ROV Nereo for benthic, or seafloor, surveys at eight sites in Elliott Bay. And here’s where things get even more futuristic: we’re harnessing the power of artificial intelligence (AI) to interpret the still images and video being captured by ROV Nereo’s cameras. Open-source AI algorithms can be “taught” to review images and identify what’s in them at a speed that simply wouldn’t be possible for a human being, or even a team of humans.

Using ROV Nereo and AI, we can learn about kelp abundance and distribution—in other words, the number of kelp plants and where they are—in Elliott Bay; see surfaces it’s growing, or not growing, on; and discover which animal species are present, competing with kelp, eating it or simply living within it.

With this information in hand, we’ll better understand why bull kelp is growing in some places but not others, and learn what conditions are needed for healthy, abundant kelp forests. That knowledge can help inform habitat restoration efforts underway throughout the region by our partners at the Puget Sound Restoration Fund and others. The ultimate goal? To reverse declines of local kelp forests, in Elliott Bay and throughout Washington waters, and develop solutions to rebuild the essential habitat that they provide.

Expanding Work

We were recently thrilled to learn that Dr. Randell and team have been awarded a grant by the Habitat Strategic Initiative Lead with funds originally from the Environmental Protection Agency to Washington Department of Fish and Wildlife and Washington Department of Natural Resources. This research, scheduled to begin later this year, will expand their work on bull kelp conservation and restoration. The team also received notice that they’d won a Sustainable Century Award in the category of “Environmental Innovation” from the Port of Seattle in April.

Ocean Pavilion brings changes

Finding solutions

Searching for sea otters on Washington’s outer coast

Scientists still have a lot of questions about sea otters

How to help sea otters in the wild

Why are sharks going extinct?

A clue on how to turn the tide

Avoiding the extinction vortex

What can individuals do?

Working Far Beyond our Walls

Connecting Research and Home

Troubled Findings and a Call to Action

On Saturday, April 22, 2023, Xbox and the Seattle Aquarium joined together for a live Earth Day celebration, including a demonstration of our remotely operated vehicle, Nereo!

Partnering with the Port of Seattle to Learn More

Kelp Conservation Meets Artificial Intelligence

Expanding Work

Website maintenance

Cyber Weekend Sale