Harmful algal blooms in the Salish Sea

Identifying kelp stocks that are tolerant of warmer waters could help the Salish Sea’s iconic underwater forests survive climate change.

They rival tropical forests in their richness and diversity, but Puget Sound's kelp beds have declined steeply in recent decades. Scientists are just starting to understand the extent of these losses. What they are finding is bringing kelp to the forefront of Puget Sound's environmental concerns.

Scientists are trying to learn how to restore Puget Sound’s diminishing kelp forests in an effort to stave off habitat loss for rockfish and other threatened species.

Environmental samplers may provide early detection of harmful algal blooms (HABs) in Puget Sound. This toxic algae is expected to increase as the climate changes, bringing with it new and potentially more severe outbreaks of shellfish poisonings. 

An algal bloom is a rapid increase or accumulation in the population of algae in a water system. While most are innocuous, there are a small number of algae species that produce harmful toxins to humans and animals.

A 2023 report from the Puget Sound Ecosystem Monitoring Program presents an overview of selected recent monitoring and research activities focused on toxic contaminants in the Salish Sea. 

This article is the latest in a series about computer models and their uses within the Puget Sound ecosystem. Today, we look at the Salish Sea Model, one of several models in the region helping to predict water circulation, water quality and food-web relationships.

In June we observed a widespread Noctiluca bloom in Central Puget Sound, evident by bright orange streaks in the water. Noctiluca blooms in Puget Sound have lasted much longer and occurred on a much larger scale than in previous years.

Estuaries around the world including Puget Sound perform an amazing feat of continuous water mixing called estuarine exchange flow. 

Nitrogen is a chemical element that is essential for the growth of all life on earth. But too much nitrogen can lead to low dissolved oxygen and other problems such as toxic algal blooms that can harm or kill aquatic organisms. 

In many parts of Puget Sound, hypoxic waters are thought to be at least in part due to overgrowth of microscopic algae, which is triggered by excess nitrogen. That means it’s important to understand the dynamics of primary productivity – the rate at which those microscopic algae, known as phytoplankton, produce organic matter through photosynthesis and in this way provide the base of the food web. Researchers are investigating different types of phytoplankton and rates of primary productivity throughout the Salish Sea, and seeking to understand how primary productivity is likely to change as climate change alters patterns of coastal upwelling and freshwater flow into the Sound.

The search goes on for a set of definitions and thresholds to represent low-oxygen concentrations that threaten various aquatic creatures. Over the years, ecologists have relocated, reshaped and revised the word “hypoxia” to describe these conditions. In part four of our series "Oxygen for life" we look at how scientists determine whether oxygen levels are low enough to be considered harmful to sea life. 

Scientists are reporting a decline in oxygen-rich waters throughout the world. Causes for the decline vary from place to place but may involve climate change and increasing discharges of tainted water. In Puget Sound, low oxygen levels can occur naturally or due to eutrophication from human-caused pollution. In this five-part series, we describe the critical nature of oxygen to Puget Sound sea life. Scientists are finding that changes in oxygen levels can lead to physiological adjustments, shifts in predator-prey relationships and other repercussions throughout the food web.

Each year, the Puget Sound Ecosystem Monitoring Program (PSEMP) releases a Puget Sound Marine Waters Overview, a report combining a wealth of data from numerous comprehensive environmental monitoring programs. The latest report provides an overview of marine conditions in 2021 and represents the collective effort of 76 contributors from federal, tribal, state, and local agencies, academia, nonprofits, and private and volunteer groups. 

The Washington State Department of Ecology has reached one hundred Eyes Over Puget Sound reports. Since 2011, Ecology has provided aerial observations and documented visible features at the surface of Puget Sound from a floatplane. This unique perspective from the air featured Puget Sound's natural beauty, its oceanographic complexity, and its ecological treasures. It also raised awareness of the challenges that the water body is facing today. Our image-rich documentation of known eutrophication indicators ranges from algal and Noctiluca blooms to macroalgae, jellyfish, and human stressors. It provides a visually captivating time-capsule of issues facing Puget Sound. The report is rich in educational and outreach material, inspired numerous news reports, and drew academic and public attention during the period of marine heat wave of the north Pacific, The Blob.

The report comes after a third year of La Nina conditions. Weak upwelling off the coast and low river flows of major rivers meant less cold, nutrient-rich, upwelled water was being entrained into Puget Sound in late summer and fall. Water conditions in Puget Sound in October were generally expected while Willapa Bay and Grays Harbor were both unusually warm and salty. Smoky air restricted our flight to Southern Puget and Central Sound where we saw blooms in terminal bays as well as patches of jellyfish. Sediment in Commencement Bay and along shorelines in Totten Inlet was unusual for a dry fall. A healthy foodweb has at its base a balance of nutrients. Explore what we found over the period of two decades of monitoring.

How do excess nutrients trigger low oxygen conditions in Puget Sound and what do those conditions mean for the species that live here?

Diverse communities of microscopic organisms called phytoplankton make up the base of the aquatic food web. In that role, they are essential to the tiny animals that eat them, but phytoplankton are not dependent on others. Thanks to chlorophyl, these tiny organisms can generate their own energy from nutrients and sunlight. Despite their critical importance to a great diversity of sea life in Puget Sound, phytoplankton can also contribute to low-oxygen conditions, and some can be harmful in other ways.

In a new series we are calling Ask a Scientist we interview local researchers to get their thoughts on some of the important but lesser-known scientific facts about the Puget Sound ecosystem. Today, we speak with University of Washington oceanographer Parker MacCready about Puget Sound’s “underwater Amazon” and why it has profound implications for Puget Sound science and policy. It all begins, he says, with the mixing of fresh and salt water and something called the estuarine exchange flow.

Puget Sound Restoration Fund has launched a network to track declining kelp populations in the Salish Sea. The three-year initiative aims to support and standardize underwater monitoring to improve kelp conservation in the region.

Low air temperatures, rain, and late snow accumulation pushed back the discharge of meltwater to Puget Sound this season. The water temperature in Puget Sound was mostly at expected levels, but cooler in South Sound by May. Central Sound saw more oxygenated conditions. This year, La Niña weather made flying for aerial photography challenging, but by June, sunny days made up for it, revealing a high number of schooling fish, unusually low tides, and a glimpse of macroalgae to come. Internal waves in Central Basin and Puget Sound, and the beauty of Puget Sound from the air, are a reminder of the unique place we live in.

The winter was cold and wet, resulting in a good snowpack in the mountains to sustain river flows into summer. In Puget Sound, saltier waters in summer transitioned to fresher conditions by fall 2021. Water temperatures in late winter 2022 are now colder and oxygen levels are high. From the air, Puget Sound looks spectacular, with few events to report. First signs of the spring bloom were visible in protected bays and passes. Port Susan and Carr Inlet already show sizable patches of drifting organic material. Small jellyfish patches were  present in Eld Inlet.

The year 2021 was generally drier and warmer including a heat wave in June. Higher river flows followed a rainy and cloudy fall. In 2021, EOPS aerial images continued to capture the diversity of phenomena on the water, with support from its wonderful contributors who documented visible water quality issues across the larger Puget Sound region. With our Artists Corner and story maps on critters in the mud, we hope to continue to inspire, educate, and motivate our community to keep curious and watchful eyes over the environment.

The tenth annual Puget Sound Marine Waters Overview looks at marine water quality and other conditions in the region in 2020. According to the report, there were few extreme weather or ecological events in 2020, but overall, conditions in Puget Sound were generally warmer, sunnier, and wetter than in typical years. The overview also examines patterns and trends in numerous environmental parameters, including plankton, water quality, climate, and marine life. 

Bull kelp is easily recognized by its wavy leaves and long, floating stipes that sometimes wash ashore like slimy green bullwhips. In that sense, it is one of the more familiar types of seaweed in Puget Sound. But as kelp forests decline throughout the region, scientists are finding that there is much about this increasingly rare species that remains a mystery.

This summer river flows were generally lower than in 2020. And in August, high air temperatures and low precipitation continued, following a drought emergency declaration in mid-July that affected also marine conditions.  The higher-than-normal salinity anomaly which persisted during summer in Puget Sound marine water is, however, eroding away, and lower-than-normal oxygen conditions developed in Central Sound in the month of August. Many blooms and organic material were reported by citizens throughout summer, and by September many colorful blooms in bays across the region continue to be active. Patches of macro-algae and organic debris are still numerous in South and Central Sound and in Padilla Bay. Jellyfish are occurring in unusual places. While we document water quality issues, we are also showcasing the natural beauty of Puget Sound through photography.

Despite a La Niña, precipitation and rain have been lower since March, leaving only snow-fed rivers running high. Due to lower rainfall and warm summer temperatures the salinity of Puget Sound is now generally higher. Strong blooms and large patches of organic material and macro-algae are building up in many places and wash onto beaches. During very hot summer days, tidal mudflats and beaches can get really warm. Beach wrack can harbor increased bacteria numbers now. See SCUBA cleaning up at Redondo beach.

The Salish Sea Model is a computer model used to predict spatial and temporal patterns related to water circulation in the Salish Sea. It was developed at the United States Department of Energy's Pacific Northwest National Laboratory with funding from the Environmental Protection Agency. It is housed at the University of Washington Center for Urban Waters which is affiliated with the Encyclopedia of Puget Sound.  

We are in a weakening La Niña, coastal downwelling has lessened and we are getting out of a cold and wet stretch, hurray. In March, rivers have almost returned to normal and carry clear water. It’s a good time to go diving if you don’t mind cold water. The productive season has only started in some places and patches of jellyfish are visible. Have a look at this edition and marvel about the secrets of the dead, or mysterious sediment clouds and the oil sheen spotted near Lummi Bay.

Rivers are flowing higher than normal since 2020. Winter weather has been warmer and wetter. In marine waters, temperatures have become too cool for Northern Pacific anchovies to tolerate in North Sound. From patches of jellyfish and snow geese, to sediment and early blooms, there is more happening in the winter than you might expect. Puget Sound has many species worth showcasing such as the heart crab – a shy critter that wears its heart on its shell.

The Washington State Department of Ecology has prepared a summary review of its Eyes Over Puget Sound surface condition reports from 2020.

A new report from the Puget Sound Ecosystem Monitoring Program details the effects of a changing climate on Puget Sound in 2019, and documents how these changes moved through the ecosystem to affect marine life and seafood consumers.

After a relatively warm summer and fall, and La Niña forming in the tropics, stream flows in the Puget Sound region are now relatively normal. Summer in Puget Sound produced lots of algal and organic material in the water and on beaches, which by October have disappeared. Kelp beds look strong in northern Puget Sound and the Straits; and the harvest of the annual chum salmon run is in full swing in Hood Canal. Jellyfish aggregations are visible in Budd and Sinclair Inlets — and some of the jellyfish might conceal a beast of another kind within. Oil sheens on the water are currently numerous.

A warm and dry summer ended with a smoky September due to massive wildfires that were followed by strong rain. As a consequence, muddy river plumes in Puget Sound are very visible, especially near the Nooksack River. During summer, many wonderful citizen contributions documented the large formation of organic material in Central Sound and helped us cover the gap in EOPS flight from April-September. By September when we started flying again, a few bays still had red-brown blooms. Nevertheless, schools of fish are abundant, and jellyfish are sparse, which is good news. Meet our new ocean acidification experts.

After a wet January, precipitation has been low and air temperatures have been cooler.  As a result, rivers gages are lower than expected, a pattern that has continued since last year. In March we approached the coldest water temperatures of the year. Herring are spawning in Port Madison. Although these cool temperatures are good for herring, temperatures are close to the survival limits for anchovies. If you can handle these temperatures, now is a good time to go diving to benefit of good underwater visibility, just avoid windy days near wave-exposed beaches. If you are lucky, you might see the kelp humpback shrimp, a master of camouflage.

Scientists are using computer models to address complex issues in the Salish Sea like the rise of harmful algal blooms and the movement of toxic PCBs. LiveOcean, Atlantis and the Salish Sea Model are three systems that are changing the game for ecologists and other researchers.

The Washington State Department of Ecology has prepared a summary review of its Eyes Over Puget Sound surface condition reports from 2019. The year started with snow, and a summer drought kept river flows low. As a result, salinities in Puget Sound were elevated year round. Warmer surface water temperatures in spring gradually extended to greater depth by late summer. The spring bloom was strong, and South Sound provided optimal conditions for anchovies that showed up in high numbers. A coccolithophore bloom stained Hood Canal turquoise, and Port Angeles and Discovery Bay were colored red-brown by strong blooms. Noctiluca and macroalgae, both known eutrophication indicators in coastal regions, were abundant in Central Sound, and extended into South Sound and Whidbey Basin. Large numbers of jellyfish occurred in Quartermaster Harbor, Sinclair Inlet, and parts of Orcas Island.

Last summer, scientists met at the University of Washington to address alarming findings concerning the rapid acidification of the world's oceans. Experts at that symposium warned that wildlife in the Salish Sea, from salmon to shellfish, may start to see significant effects from changing water chemistry within the next 10 to 20 years. This article summarizes the symposium's key findings and was commissioned and edited by the Washington Ocean Acidification Center which hosted the gathering. Funds for the article were provided by the Washington state legislature. [A version of this article was originally published by the Washington Ocean Acidification Center.]

After a dry early summer followed by more than expected rain, rivers mostly remained lower than in 2018. In October air temperatures dropped, but water temperatures remained warm enough for spawning anchovies in South and Central Sound and herring and salmon optimal growth in Whidbey Basin. By the end of October many red-brown blooms vanished, yet the waters of South Sound are still green, adorned with rafts of organic debris in many places. Read what happened the year before in the Puget Sound Marine Waters 2018 Overview.

A new report from the Puget Sound Ecosystem Monitoring Program says climate change altered the base of Puget Sound's food web in 2018, diminishing microscopic phytoplankton necessary for marine life. Scientists also observed lower abundances of fish, seabirds, and marine mammals.

This year, air temperatures were warmer than in previous years, and this pattern is predicted to continue. Precipitation was low and is now improving, yet river flows remain low. By August, Puget Sound surface water temperatures were 0.6 °C warmer across all regions; this could have shifted the timing of optimal temperatures for some marine organisms. In September, blooms are limited to inlets. Jellyfish are abundant in Sinclair Inlet, and anchovies reside in Eld Inlet. Macroalgae are still plentiful. Learn about the benefits of beach wrack and a DNA barcoding project supported by Ecology.

In July, the recent trends of warm, dry conditions lessened; however, river flows remain low. Extensive macroalgae drifted through South and Central Sound and washed up on beaches. Macroalgae growth is fueled by excessive nutrients and sunshine. When it washes onto the beach, it is called beach wrack, and it can be a health risk to beachgoers because of bacteria it can harbor. From our aerial photography, we saw that Southern Hood Canal looks tropical because of a bloom of coccolithophores coloring the water turquoise. Schools of fish congregate in South Sound and southern Hood Canal. Jellyfish are abundant in Quartermaster Harbor.

A 2019 paper in the Journal of Geophysical Research: Oceans outlines how the Salish Sea Model describes the impacts of climate change, sea level rise and nutrient loads on the region's nearshore environment.

Warm and dry conditions this spring are predicted to persist into summer, resulting in saltier and warmer than normal Puget Sound water conditions. Early upwelling and a premature melt of the snowpack means nutrient-rich ocean water likely already entered Puget Sound. This sets the stage for a lot of biological activity. From the air, it is obvious that the productive season is in full swing. We saw large algae blooms in Central Sound along with abundant Noctiluca.  Huge numbers of anchovies were documented in Case Inlet and other finger inlets in South Sound, attracting hundreds of marine mammals.

A 2019 report from the Puget Sound Ecosystem Monitoring Program presents an overview of selected recent monitoring and research activities focused on toxic contaminants in the Salish Sea. 

Although fall and winter were warm, February brought cold snowy weather and low river flows. Despite colder air temperatures, the productive season has already started in Hood Canal and Holmes Harbor. Puget Sound waters were warmer than expected through January, and the warmest waters were in Hood Canal, possibly creating a thermal refuge for cold-sensitive species such as anchovies. We saw lots of sea lions feasting on anchovies in Case Inlet, and we may have captured some herring spawning activity. Unusual for mid-winter, we saw jellyfish patches in Eld and Budd inlets. See the new publication about ocean acidification featuring twenty-five years of our marine monitoring data!

In 2018, water temperatures were slightly warmer than normal. Aerial photos revealed many spawning herring and baitfish as well as algal blooms. We also saw abundant macro-algae, a persistent Noctiluca bloom, and countless red blooms. Were these observations related to the cool, wet spring followed by a warm, dry, and sunny summer? Or did the neutral boundary conditions in the Pacific Ocean also play a role? A full summary is available in the report. 

The Puget Sound Ecosystem Monitoring Program has released its seventh annual Marine Waters Overview. The report provides an assessment of marine conditions for the year 2017 and includes updates on water quality as well as status reports for select plankton, seabirds and fish.

Air temperatures have remained high with precipitation and river flows below normal, extending the summer’s unusual conditions. Water temperatures were warmer in August, perhaps too warm for bull kelp and some salmon species in South Sound. In contrast, Hood Canal, North Sound, and the San Juan Islands provide optimal growth temperatures for herring and salmon. Many terminal inlets of Puget Sound are experiencing extensive red-brown blooms. Jellyfish patches are developing in South Sound finger Inlets and remnants of floating macroalgae occur in the nearshore areas of South Sound and in Useless Bay. At times floating organic material we see from the air ends up on the shoreline were our BEACH team documents it.

During June, near normal air temperatures and continued low precipitation have resulted in highly variable freshwater inputs to Puget Sound. A large Noctiluca bloom extends across the South Central Basin of Puget Sound. Coccolithophores are blooming in Hood Canal. Macroalgae is drifting as mats on the water in Port Madison, South Central Basin, and South Sound. They are also piling up on beaches in South and Central Puget Sound and Whidbey Basin. Juvenile fish are migrating out of the estuaries and meeting a complex thermal habitat. New infrared images tell the story. Meet our ocean acidification expert, Stephen Gonski.

Rainfall in May was extremely low: The third lowest amount ever recorded. Rivers are responding differently depending upon whether they received water from rain or snow, which is melting rapidly. With projected drier and warmer conditions, can the remaining snowpack maintain healthy streamflows this summer? Seawater is already getting saltier than normal in response to the lack of rain. We see algal blooms in many colors. What is that orange stuff out there? It’s a Noctiluca bloom and organic material drifting at the surface stretching from South to Central Sound and Whidbey Basin.

Kelps are large seaweeds in the order Laminariales that form dense canopies in temperate rocky intertidal and subtidal habitats less than 30 m in depth. The kelp flora of the Pacific Northwest is one of the most diverse in the world.

As the region's population grows, scientists say we can expect to see increasing amounts of nitrogen and other elements flowing into Puget Sound. Known as “nutrients” these elements are naturally occurring and even necessary for life, but officials worry that nutrients from wastewater and other human sources are tipping the balance. That could mean big problems for fish and other marine life, gradually depleting the water of oxygen and altering the food web.

A regional sewage-treatment system in Thurston County has helped contain  low-oxygen problems in Budd Inlet as the population continues to grow. The system cleans up some of the effluent for replenishing groundwater supplies.

High amounts of elements such as nitrogen can cause blooms of phytoplankton that sometimes trigger perturbations throughout the food web. This occurs most often in the spring and summer after the long, dark, cloudy days of winter begin to fade.

Under the federal Clean Water Act, states are required to assess the quality of their surface waters and compile a list of polluted water bodies. The law mandates cleanup plans to address pollution and other water-quality problems. This article describes how this process works in Washington state for dissolved oxygen. 

The Washington Marine Resources Advisory Council has released an addendum to the 2012 report Ocean Acidification: From Knowledge to Action. The original report established a statewide strategy for addressing ocean acidification in Washington. The addendum identifies updates based on emerging science and management practices and is intended to be a companion to the 2012 report. 

Sea lions living along the coast of Washington are at risk from harmful algal blooms throughout the year, according to a 2017 study published in the Marine Ecology Progress Series.

The Puget Sound Ecosystem Monitoring Program has released its sixth annual Marine Waters Overview. The report provides an assessment of marine conditions for the year 2016 and includes updates on water quality as well as status reports for select plankton, seabirds and fish.

The Puget Sound Ecosystem Monitoring Program (PSEMP) is an independent program established by state and federal statute to monitor environmental conditions in Puget Sound. 

Invasive species are considered a top threat to the balance of ecosystems worldwide. New discoveries of non-native green crabs in Puget Sound have highlighted that concern here at home, but invasive species can impact more than just the food web. Some introduced species can produce toxins that accumulate in shellfish or by directly infecting the human body.

The Puget Sound Ecosystem Monitoring Program released its fifth annual Marine Waters Overview this week. The report provides an assessment of marine conditions for the year 2015 and includes updates on water quality as well as status reports for select plankton, seabirds, fish and marine mammals.

Through June, air temperatures and sunlight were higher than normal. Recent rain generally improved river flows. However, the Fraser river flow remains extremely low, reducing water exchange with the ocean. Water temperatures are still breaking records, yet dissolved oxygen levels are normal. Coastal bays are influenced by upwelling and exhibit lower oxygen and higher salinities. Puget Sound algae are thriving with blooms observed in many South Sound inlets. Macro-algae is seen piling up on beaches and drifting in Central Sound. Jellyfish smacks are numerous in Eld and Budd Inlets. Our fliers notice seals hanging out at the beach!

It turns out that a gooey substance known as biofilm is a big deal for Salish Sea shorebirds, providing critical food for some species. But could a proposed port expansion in Vancouver threaten this slimy resource?

Researchers are studying how persistent pollutants such as PCBs avoid settling to the bottom of Puget Sound. This article continues our coverage of new theories on the spread of toxic chemicals in the food web. 

Lake Washington was heavily contaminated by untreated sewage until extensive pollution controls by the city of Seattle. 

A report from NOAA and the Puget Sound Ecosystem Monitoring Program provides an overview of 2014 marine water quality and conditions in Puget Sound from comprehensive monitoring and observing programs.

A report from the Puget Sound Ecosystem Monitoring Program provides an overview of 2013 marine water quality and conditions in Puget Sound from comprehensive monitoring and observing programs.

The Puget Sound Marine Waters 2012 Overview from the Puget Sound Ecosystem Monitoring Program synthesizes conditions measured in 2012 and has been expanded to include observations on seabirds that rely on marine waters. Read an excerpt below, or download the full report.

Once a month, Washington State Department of Ecology marine scientists take to the air to obtain high-resolution aerial photo observations and gather water data at the agency's monitoring stations and via state ferry transects. This provides a visual picture of the health of Puget Sound, which they call Eyes Over Puget Sound or EOPS.

An independent review conducted by the Puget Sound Institute (PSI) is featured in findings by the Environmental Protection Agency and the Washington State Department of Ecology that there is currently “no compelling evidence” that humans are the cause for recent trends in declines in dissolved oxygen in Hood Canal.

The Puget Sound Marine Waters 2011 report is now available. The report was produced by the Puget Sound Ecosystem Monitoring Program and assesses the condition and quality of the waters of Puget Sound. 

Non-native species are those that do not naturally occur in an ecosystem. A non-native species is considered invasive when it is capable of aggressively establishing itself and causing environmental damage to an ecosystem. Plants, animals, and pathogens all can be invasive.