Tiny pieces of plastic in the ocean might seem innocuous on their own, but their growing presence is . The particles’ small size makes them difficult to clean up, and it also allows them to easily burrow into marine environments or even get ingested by ocean organisms.

Two 91爆料 researchers are using very different methods to investigate the issue of marine microplastics. , a 91爆料 associate professor of aquatic and fishery sciences, to study how microplastics are affecting coral reef ecosystems. , a 91爆料 assistant professor of mechanical engineering, to study how microplastics move across the ocean surface.

For Earth Day, 91爆料 News asked them to discuss their research.

Professor Padilla-Gami帽o, your lab鈥檚 experimental study in 2019 showed that corals are ingesting microplastics along with their typical food. Why are microplastics a problem for corals and other marine organisms?

Jacqueline Padilla-Gami帽o: This material can prevent them from feeding, or damage their tissues. Plastics also contain plasticizers 鈥� chemicals used to provide flexibility and to reduce brittleness 鈥� which may cause hormone disruption and affect the organisms’ reproduction.

What have you learned since then?

JPG: We have continued to explore the abundance and diversity of microplastics in coral reefs, including in water, sediments and other organisms, such as sea cucumbers.

We are also doing other experiments to learn how different types of plastics can affect the performance of corals, because not all plastics are the same.

It鈥檚 scary to think that corals and other marine organisms, which are already stressed by warming and acidifying oceans, are at the same time also consuming microplastics. How can research offer any hope?

JPG: Research can help us to understand what species are more sensitive to plastics. It can also help us to generate ecological baselines that can be used to assess impacts. Both can help us design strategies to reduce plastic pollution’s impacts.

What motivated you to incorporate microplastics into your wider area of research on how climate change affects marine organisms?

JPG: Plastic pollution is a global problem and it is also a carbon dioxide problem. The process of plastic manufacturing creates more than a . At least end up in the ocean every year. We need to understand the impacts of these plastics in marine ecosystems.

Professor DiBenedetto, what motivated you to study the movement of microplastics?

Michelle DiBenedetto: Plastic pollution is a relatively new issue and there is still a lot we do not know about what happens to plastic once it is in the ocean. For example, we do not know exactly how long it takes to degrade in the ocean, where it might settle out or at what rates it will be deposited on our beaches.

Many of these processes are influenced by the fluid dynamics in the ocean, such as waves, turbulence, wind and currents. How plastic behaves and is transported in the ocean is an interesting problem because plastic is different from traditionally studied ocean topics, such as bubbles, oil spills, sediment and biology. Thus, it leads to a lot of interesting physical questions that we can study in the lab.

Can you describe what those experiments look like?

MD: We turn on an adjustable wind tunnel that blows over the surface of a wave tank. This creates waves, turbulence and current in the water.

Next, we release particles upstream in the tank. In the middle of the tank, we have an area where we can take images of the particles. We use cameras and lighting to illuminate the particles so we can track their position and orientation (when using non-spherical particles). We either track the particle shadows, or we track the particles themselves.

How will tracking the particles in this way better inform our knowledge of microplastics transport in the ocean? Could this potentially help us design future cleanup methods?

MD: The goal of this research is to be able to develop a fundamental model for microplastics’ vertical distribution at the ocean surface: How far below the surface do we expect buoyant microplastics to be mixed under different conditions?

This model would increase the accuracy of simulations of microplastics transport (ocean currents are typically faster at the surface) and degradation rates (sunlight degrades microplastics and is strongest at the surface). A model would also decrease uncertainty in measurements 鈥� we have many surface measurements of microplastics, but these need to be corrected for the number of microplastics mixed below the surface.

To design effective cleanup methods, we need to know how fast microplastics leave the ocean surface naturally, so that we can decide the value in designing cleanup methods 鈥� or focus our energies on polluting less plastic in the first place. This work’s goal is to better our understanding of plastic’s natural transport and fate in the ocean so we can decide how best to manage it.

For more information, contact Padilla-Gami帽o at jpgamino@uw.edu and DiBenedetto at mdiben@uw.edu.

Coral reefs聽are among the most diverse ecosystems in the world, protecting coastlines from erosion and supporting more than 500 million people through tourism and fishing livelihoods.聽But at the current rate of global warming, mass coral bleaching is expected to become more frequent and severe worldwide.

Coral bleaching is a significant problem for the world鈥檚 ocean ecosystems: When coral becomes bleached, it loses the algae that live inside it, turning it white. Corals can survive a bleaching event, but while they are bleached they are at higher risk for disease and death.

Now an international consortium of scientists, including a coral researcher from the 91爆料, has created the first-ever common framework for increasing comparability of research findings on coral bleaching. The work, described in a paper Nov. 21 in the journal Ecological Applications, provides a common language and reference points for researchers to compare results across studies.

鈥淚t is very important to find better and more efficient ways to perform experiments that can help us to understand the vulnerability, tolerance and resilience of these ecosystems,鈥� said co-author , an assistant professor in the 91爆料 School of Aquatic and Fishery Sciences who studies coral physiology and reproduction. 鈥淥ur work will provide an incredible platform that scientists around the world can use to develop more open and collaborative science.鈥�

The framework covers a broad range of variables that scientists generally monitor in their experiments, including temperature, water flow, light and other factors. It does not dictate what levels of each should be present during an experiment into the causes of coral bleaching; rather, it offers a common framework for increasing comparability of reported variables.

鈥淐oral bleaching is a major crisis, and we have to find a way to move the science forward faster,鈥� said聽lead author , professor of聽earth sciences聽at The Ohio State University.

The consortium leading this effort is the聽, an international group of coral researchers. Twenty-seven scientists, representing 21 institutions around the world, worked together as part of a workshop at Ohio State in May 2019 to develop the common framework.

The goals are to allow scientists to compare their work, make the most of the coral samples they collect and find ways to create a common framework for coral experimentation.

Their recommendations include guidelines for experiments that help scientists understand what happens when corals are exposed to changes in light or temperature over a short period of time, a moderate period and long periods. The guidelines include a collection of the most common methods used for recording and reporting physical and biological parameters in a coral bleaching experiment.

鈥淩eefs are in crisis,鈥� Grottoli said. 鈥淎nd as scientists, we have a responsibility to do our jobs as quickly, cost-effectively, professionally and as well as we can. The proposed common framework is one mechanism for enhancing that.鈥�

That such a framework hasn鈥檛 already been established is not surprising: The scientific field that seeks to understand the causes of and solutions for coral bleaching is relatively young. The first reported bleaching occurred in 1971 in Hawaii; the first widespread bleaching event was reported in Panama and was connected with the 1982-83 El Ni帽o.

But experiments to understand coral bleaching didn鈥檛 really start in earnest until the 1990s 鈥� and a companion paper by many of the same authors found that two-thirds of the scientific papers about coral bleaching have been published in the last 10 years.

Researchers are still trying to understand why some coral species seem to be more vulnerable to bleaching than others, and setting up experiments with consistency will help the science move forward more quickly and economically.

鈥淲e鈥檇 be able to better collaborate, and to build on one another鈥檚 work more easily. It would help us progress in our understanding of coral bleaching 鈥� and because of climate change and the vulnerability of the coral, we need to progress more quickly,鈥� Grottoli said.

Other paper co-authors are from University of Hawaii at M膩noa, Florida Institute of Technology, University of Delaware, Texas A&M University, Pennsylvania State University, University of North Carolina at Chapel Hill, University at Buffalo 鈥� State University of New York, John G. Shedd Aquarium, Oregon State University, Duke University, University of Alabama at Birmingham, University of Southern California, Smithsonian Tropical Research Institute, U.S. Geological Survey, University of Technology Sydney, National Oceanic and Atmospheric Administration, Stanford University and University of Konstanz.

This work was funded by the National Science Foundation.

Adapted from an Ohio State .

Plastic pollution is an increasingly present threat to marine life and one which can potentially impact your dinner table.聽

Oysters, and other economically valuable shellfish, filter their food from the water where they may also inadvertently capture tiny microplastics. The ingestion and accumulation of these microplastics can have detrimental effects on their health and may be passed to other animals, including humans, through the food chain.

In a recent interdisciplinary study, 91爆料 researchers at the School of Aquatic and Fishery Sciences, Department of Chemistry and Department of Materials Science and Engineering used advanced methodologies to accurately identify and catalog microplastics in Pacific oysters from the Salish Sea. They have discovered that the abundance of tiny microplastic contaminants in these oysters is much lower than previously thought. The were published in January in the journal Science of the Total Environment.

鈥淯ntil now, not a lot of chemical analysis has been done on microplastics in oysters,鈥� said co-author , a 91爆料 doctoral student in chemistry. 鈥淭he microplastics that chemists have looked at in previous studies are slightly bigger and easy to visually recognize, but with oysters, the microplastics are much smaller and harder to identify.鈥�

In their study, the team sampled wild Pacific oysters harvested from Washington鈥檚 state parks throughout the Salish Sea. Using standard processing methods, the oysters鈥� tissue is dissolved and the remaining solution is passed through a filter. The filter collects all of the possible microplastic particles.

鈥淥bservation of filters is the method researchers have typically used, so if we had stopped there, we would have thought all the oysters had microplastics because small particles were present in most of the filters,鈥� said lead author , a 91爆料 postdoctoral researcher at the School of Aquatic and Fishery Sciences.聽聽

Martinelli鈥檚 initial observations under a dissecting microscope revealed what were thought to be high numbers of microplastics left behind in the testing filters, but when Phan further analyzed those filters with three advanced chemical identification techniques, they realized that most of what was left in the filters was not actually plastic.

鈥淲hen we’re characterizing plastics, or any polymers in chemistry in general, we have to use multiple techniques, and not every technique will give you a full picture. It’s half a picture or just part of the picture,鈥� said Phan. 鈥淲hen you put all those pictures and characterizations together, you can have a more complete understanding of what the composition or identities of these particles are.鈥�

During their analyses, the team realized that many of the particles were, in fact, shell fragments, minerals, salts and even fibers from the testing filters themselves. In the end, they found that only about 2% of the particles distilled from the oysters could be confirmed as plastics.聽

鈥淢ost people so far have not used the combination of techniques or instruments that we used,鈥� said Martinelli. 鈥淚t’s really easy to stop at the first part and say, 鈥極h, there’s a lot of particles here. They look like plastic. They must be plastic.鈥� But when you actually go deeper into the chemical composition, they might not be.鈥�

The number of plastic particles that the team found was relatively low compared to the total number of particles analyzed; however, they stress that while it appears Pacific oysters are not accumulating large amounts of plastic, they could not identify 40% of the particles observed due to technical limitations. The researchers also acknowledge that while using a combination of instruments is the most complete way to analyze these particles, access to the equipment, elevated costs and the extremely time-consuming nature of the work are limiting factors for widespread use.

As suspension feeders, oysters pull in water and the particles present in it when they inhale. Particles are then sorted in and out of the animal through their gills. Previous experiments have shown that when oysters are given microfibers or microbeads, they expel the majority of them either immediately or after a few hours. The hypothesis is that oysters鈥� gill anatomy and physiology might be the reason why the team did not see large amounts of plastic accumulation in their samples.

鈥淎 lot of this has to do with how the oysters process water through their gills and how they get rid of particles,鈥� said Martinelli. 鈥淚t doesn’t mean microplastics are not in the water, it means that the animals are better at expelling them.鈥澛�

In agreement with this, it has been suggested that suspension-feeding bivalves like oysters might not be good indicators of pollution in estuaries because they naturally expel microplastics instead of ingesting them, which is good news for consumers that like eating oysters.

Other co-authors are , a 91爆料 professor of materials science and engineering, and , a 91爆料 assistant professor of aquatic and fishery sciences.

This research was supported by NOAA-SK and the Royal Research Fund awarded to Padilla-Gami帽o. Part of this work was conducted at the Molecular Analysis Facility, a National Nanotechnology Coordinated Infrastructure site at the 91爆料 supported in part by the National Science Foundation, the 91爆料, the Molecular Engineering & Sciences Institute and the Clean Energy Institute, and the Washington Research Foundation.

For more information, contact Martinelli at julimar@uw.edu and Phan at samphan@uw.edu.

Grant number:聽 NNCI-1542101 (NSF)

Tiny microplastic particles are about as common in the ocean today as plastic is in our daily lives.

Synthetic clothing, containers, bottles, plastic bags and cosmetics all degrade and release microplastics into the environment. Corals and other marine organisms are eating microplastics that enter the waterway. Studies in this emerging field show some harmful effects, but it’s largely unknown how this ubiquitous material is impacting ocean life.

A new experiment by the 91爆料 has found that some corals are more likely to eat microplastics when they are consuming other food, yet microplastics alone are undesirable. Two coral species tested responded differently to the synthetic material, suggesting variations in how corals are adapting to life with microplastics. The was published Dec. 3 in the journal Scientific Reports.

“The more plastic we use, the more microplastics there are, and the more corals are going to be exposed,” said lead author , a 91爆料 doctoral student in the School of Aquatic and Fishery Sciences. “Our study found that some corals probably won’t eat microplastics and will keep going about their daily business. But some might 鈥� and if they happen to be sensitive to warmer ocean temperatures or other stressors, this is just another compounding factor to be worried about.”

Corals are tiny animals that are rooted to the reef or rocks on the ocean floor. They use tentacle-like arms to sweep food into their mouths. Many rely on algae for energy, but most also consume drifting animals for survival.

This study is the first to examine whether corals eat microplastics when exposed to warmer water, which is expected to accelerate with climate change. Rising ocean temperatures can be deadly for coral: warm water stresses them, causing corals to lose their symbiotic algae partner that undergoes photosynthesis and provides energy for them to survive. When this happens, coral bleaching and eventual death can occur.

But some corals have adapted to bleaching by shifting their diets to feed on tiny marine organisms called zooplankton, which provide an alternate energy source. As they munch on these small animals 鈥� often the same size as microplastics 鈥� the research team wondered whether they also were ingesting plastic fragments.

The experiment shows corals do eat microplastics when they switch to a zooplankton diet, adding one more stressor for corals in a changing ocean environment.

“Microplastics are not as simple as a life-or-death threat for corals 鈥� it’s not that black or white,” said senior author , assistant professor at the 91爆料 School of Aquatic and Fishery Sciences. “It’s about total energy lost. If corals constantly are dealing with microplastics, it might not kill them, but there will be less energy for them to grow and to reproduce.”

The researchers collected two species of common corals off the east coast of Oahu, Hawaii, and exposed half of each species to warmer water for several weeks to induce stress and bleaching. Then they ran four different feeding experiments on both bleached and non-bleached corals: corals were fed only microplastics; only a type of zooplankton; microplastics and zooplankton; or nothing.

After dissecting the coral polyps, researchers found that corals stressed by warmer temperatures actually ate much less than their counterparts in normal seawater. This was unexpected and possibly due to stress from high water temperatures. However, one of the two species, known for its voracious eating habits in the wild, consumed microplastics only while also eating zooplankton. Neither coral species ate microplastics alone.

The researchers don’t know why one species of coral readily ate microplastics in the presence of other food, but avoided microplastics when they were the only thing on the menu. They suspect that this species of coral can read certain chemical or physical cues from the plastics and the prey, but might not be able to distinguish between the two when both are present.

It’s also possible the plastic used in this experiment is less desirable to corals, and that plastics with a different chemical makeup could, in fact, be tasty to corals. The researchers plan to test the “tastiness” of other types of microplastics, such as synthetic fibers from clothing.

Ultimately, some coral species likely face greater risks from exposure to microplastics than others, the study found. The researchers will look next at impacts on the physiology of corals that are exposed over a longer period to microplastics.

“Knowing that will provide a lot more context to this work,” Axworthy said. “We need to know the full physiological impacts of chronic exposure to microplastics on corals, especially at increased temperatures, to understand how serious the problem is.”

In the meantime, the problem of microplastics isn’t going away. A 2014 estimate found between 15 and 51 trillion microplastic particles in the oceans, and plastic waste entering the oceans is expected to increase tenfold between 2010 and 2025.

“It’s important when talking about waste management to think big picture 鈥� what are we putting in the oceans?” Padilla-Gami帽o said. “We don鈥檛 know where plastic goes, where it stays, who grabs it, and what are the mechanisms by which we get it back. We are just at the tip of understanding these implications.”

This research was funded by the National Science Foundation.

For more information, contact Axworthy at jeremyax@uw.edu and Padilla-Gami帽o at jpgamino@uw.edu.

Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to published July 4 in the journal Marine Ecology Progress Series. The researchers found that the number of young corals on tropical reefs has declined by 85%聽鈥� and doubled on subtropical reefs聽鈥� during the last four decades.

鈥淐limate change seems to be redistributing coral reefs, the same way it is shifting many other marine species,鈥� said lead author , a senior research scientist at Bigelow Laboratory for Ocean Sciences in Maine. 鈥淭he clarity in this trend is stunning, but we don鈥檛 yet know whether the new reefs can support the incredible diversity of tropical systems.鈥�

As climate change warms the ocean, subtropical environments are becoming more favorable for corals than the equatorial waters where they traditionally thrived. This is allowing drifting coral larvae to settle and grow in new regions. These subtropical reefs could provide refuge for other species challenged by climate change and new opportunities to protect these fledgling ecosystems.

“This study is a great example of the importance of collaborating internationally to assess global trends associated with climate change and project future ecological interactions,” said co-author , an assistant professor at the 91爆料 School of Aquatic and Fishery Sciences. “It also provides a nugget of hope for the resilience and survival of coral reefs.”

The researchers believe that only certain types of coral are able to reach these new locations, based on how far the microscopic larvae can swim and drift on currents before they run out of their limited fat stores. The exact composition of most new reefs is currently unknown, due to the expense of collecting genetic and species diversity data.

鈥淲e are seeing ecosystems transition to new blends of species that have never coexisted, and it鈥檚 not yet clear how long it takes for these systems to reach equilibrium,鈥� said co-author , an associate professor at Okinawa Institute of Science and Technology Graduate University who earned his doctorate at the 91爆料. 鈥淭he lines are really starting to blur about what a native species is, and when ecosystems are functioning or falling apart.鈥�

New coral reefs grow when larvae settle on suitable seafloor away from the reef where they originated. The research team examined latitudes up to 35 degrees north and south of the equator, and found that the expansion of coral reefs is perfectly mirrored on either side. The paper assesses where and when 鈥渞efugee corals鈥� could settle in the future聽鈥� potentially bringing new resources and opportunities such as fishing and tourism.

The researchers, an international group from 17 institutions in six countries, compiled a global database of studies dating back to 1974, when record-keeping began. They hope that other scientists will add to the database, making it increasingly comprehensive and useful to other research questions.

鈥淭he results of this paper highlight the importance of truly long-term studies documenting change in coral reef communities,鈥� said co-author , a professor at California State University, Northridge. 鈥淭he trends we identified in this analysis are exceptionally difficult to detect, yet of the greatest importance in understanding how reefs will change in the coming decades. As the coral reef crisis deepens, the international community will need to intensify efforts to combine and synthesize results as we have been able to accomplish with this study.鈥�

Coral reefs are intricately interconnected systems, and it is the interplay between species that enables their healthy functioning. It is unclear which other species, such as coralline algae that facilitate the survival of vulnerable coral larvae, are also expanding into new areas 颅鈥� or how successful young corals can be without them. Price wants to investigate the relationships and diversity of species in new reefs to understand the dynamics of these evolving ecosystems.

鈥淪o many questions remain about which species are and are not making it to these new locations, and we don鈥檛 yet know the fate of these young corals over longer time frames,鈥� Price said. 鈥淭he changes we are seeing in coral reef ecosystems are mind-boggling, and we need to work hard to document how these systems work and learn what we can do to save them before it鈥檚 too late.鈥�

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For more information, contact Padilla-Gami帽o at jpgamino@uw.edu.

This post was adapted from a Bigelow Laboratory for Ocean Sciences .

There’s聽an area of the ocean known as the聽聽that is still largely unexplored 鈥� where waters are about 100 to at least 500 feet deep, and little to no light breaks through.聽Little is known about the coral reefs at that depth because it’s just beyond where conventional divers can go.

, an assistant professor in the 91爆料 School of Aquatic and Fishery Sciences,聽spent up to eight hours at a time in the cramped quarters of a submersible watercraft, studying the largest known coral reef in the mesophotic zone, located in the Hawaiian Archipelago. With a robotic arm, her research team collected specimens of coral, and captured video footage and photos of underwater life that has rarely been seen by humans.

Her work documented life along the coral reef, finding a surprising amount of coral living in areas where light levels are less than 1% of the light available at the surface.

鈥淚t鈥檚 a really unbelievable place,鈥� Padilla-Gami帽o said. 鈥淲hat is surprising is that, in theory, these corals should not be there because there鈥檚 so little light. Now we鈥檙e finally understanding how they function to be able to live there.鈥�

Read more about the mesophotic coral study in a related .

Just beyond where conventional scuba divers can go is an area of the ocean that still is largely unexplored. In waters this deep 鈥� about 100 to at least 500 feet below the surface 鈥� little to no light breaks through.

Researchers must rely on submersible watercraft or sophisticated diving equipment to be able to study ocean life at these depths, known as the . These deep areas span the world’s oceans and are home to extensive coral reef communities, though little is known about them because it is so hard to get there.

A collaborative research team from the 91爆料, College of Charleston, University of California Berkeley, University of Hawaii and other institutions has explored the largest known coral reef in the mesophotic zone, located in the Hawaiian Archipelago, through a series of submersible dives. There, they documented life along the coral reef, finding a surprising amount of coral living in areas where light levels are less than 1% of the light available at the surface.

Their were published this spring in the journal Limnology and Oceanography.

“Because mesophotic corals live close to the limits of what is possible, understanding their physiology will give us clues of the extraordinary strategies corals use to adapt to low-light environments,” said lead author , an assistant professor in the 91爆料 School of Aquatic and Fishery Sciences.

Knowing how these deep coral reefs function is important because they appear to be hotspots for biodiversity, and home to many species found only in those locations, Padilla-Gami帽o explained. Additionally, close to half of all corals in the ocean have died in the past 30 years, mostly due to warm water temperatures that stress their bodies, causing them to bleach and eventually die. This has been documented mostly in shallower reefs where more research has occurred. Scientists say that more information about deeper reefs in the mesophotic zone is critical for preserving that habitat.

“Mesophotic reefs in Hawaii are stunning in their sheer size and abundance,” said co-author at College of Charleston. “Although mesophotic environments are not easily seen, they are still potentially impacted by underwater development, such as cabling and anchoring, and need to be protected for future generations. We are on the tip of the iceberg in terms of understanding what makes these astounding reefs tick.”

Padilla-Gami帽o was on board during two of the team’s eight submersible dives off the coast of Maui that took place from 2010 to 2011. Each dive was a harrowing adventure: Researchers spent up to eight hours in cramped quarters in the submersible that was tossed from the back of a larger boat, then disconnected once the submersible reached the water.

Once in the mesophotic zone, they collected specimens using a robot arm, and captured video footage and photos of life that has rarely been seen by humans.

“It’s a really unbelievable place,” Padilla-Gami帽o said. “What is surprising is that, in theory, these corals should not be there because there’s so little light. Now we’re finally understanding how they function to be able to live there.”

By collecting coral samples and analyzing their physiology, the researchers found that different corals in the mesophotic zone use different strategies to deal with low amounts of light. For example, some species of corals change the amount of pigments at deeper depths, while other species change the type and size of symbionts, which are microscopic seaweeds living inside the tissue of corals, Padilla-Gami帽o explained. These changes allow corals to acquire and maximize the light available to perform photosynthesis and obtain energy.

Additionally, the corals at deeper depths are likely eating other organisms like zooplankton to increase their energy intake and survive under very low light levels. They probably do this by filter feeding, Padilla-Gami帽o said, but more research is needed to know for sure.

The researchers hope to collect more live coral samples from the mesophotic zone to be able to study in the lab how the symbionts, and the corals they live inside, function.

“The more we can study this, the more information we can have about how life works. This is a remarkable system with enormous potential for discovery,” Padilla-Gami帽o said. “Our studies provide the foundation to explore physiological 铿俥xibility, identify novel mechanisms to acquire light and challenge current paradigms on the limitations of photosynthetic organisms like corals living in deeper water.”

Other co-authors are Celia Smith at University of Hawaii at M膩noa; Melissa Roth at UC Berkeley; Lisa Rodrigues at Villanova University; Christina Bradley at Salisbury University; and Robert Bidigare and Ruth Gates at Hawaii Institute of Marine Biology.

The study was funded by the National Oceanic and Atmospheric Administration and the National Science Foundation.

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For more information, contact Padilla-Gami帽o at jpgamino@uw.edu or 206-543-7878.