Harmful algal blooms

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. This section includes articles related to general information about harmful algal blooms and some of their impacts. 

Source: Sound Science 2007.

Due to the 'Red Tide' misnomer, blooms of red-colored algae, like this Noctiluca sp. (a dinoflagellate) seen here in Eastsound, Washington (July 2016), can cause undue public concern about harmful algal blooms. Photo: Jordan Cole

OVERVIEW

Harmful algal blooms in the Salish Sea

Formerly known as “Red Tide”, harmful algal blooms are a health concern for both wildlife and humans. The following is a brief review of some of these algae and their effects.

RELATED ARTICLES

Monitoring devices deployed by NOAA for detecting harmful algal blooms. Photo by Rachael Mueller.
7/12/2016

Salish Sea snapshots: Detecting harmful algal blooms

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. 

Algal bloom. Photo: Eutrophication&Hypoxia (CC BY 2.0) https://www.flickr.com/photos/48722974@N07/5120831456
2/26/2016

Harmful algal blooms in Puget Sound

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.

Infographic describing impacts of low oxygen on Puget Sound aquatic life
5/11/2023

Impacts of low oxygen on Puget Sound aquatic life (infographic)

Chronic stress from lack of oxygen can make aquatic organisms more vulnerable to disease, pollution, or predation. Low oxygen can also result in reduced habitat for some species. Aquatic species may escape, acclimate, adapt, or die with exposure.

Report cover
1/20/2023

Eyes Over Puget Sound: A Decade in Review

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.

View of Puget Sound with red-orange water near the shoreline and blue sky with clouds above land in the distant background.
12/5/2022

Understanding the causes of low oxygen in Puget Sound

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

Microscopic view of diatoms in various shapes and sizes.
12/4/2022

Tiny plankton play a mighty role in the health of Puget Sound

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.

Report cover
12/2/2020

2019 Puget Sound Marine Waters Overview

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.

Map showing a marine heat wave known as "the blob" which spread across the northeastern Pacific Ocean from 2014 to 2016. Image: Joshua Stevens/NASA Earth Observatory, Data: Coral Reef Watch
7/24/2020

'The blob' revisited: Marine heat waves and the Salish Sea

Years after the appearance of the devastating marine heat wave known as "the blob," scientists are still working to understand how it has affected the Salish Sea. In some ways, they say, it is like the blob never left.

Locations of shellfish beds in the Salish Sea (left) compared to regions predicted by the Salish Sea Model to have high microplastic accumulation (right). Maps: PNNL
3/30/2020

Ecosystem models expand our understanding of the Salish Sea

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.

Eyes Over Puget Sound report cover
8/7/2019

Eyes Over Puget Sound: Surface Conditions Report - July 29, 2019

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.

Predicted annual average Δ in surface temperature and salinity over (a) the entire Salish Sea domain, as well as (b) in the nearshore intertidal regions of the Snohomish River estuary (see Khangaonkar et al. 2019 for details).  Image courtesy of Journal of Geophysical Research: Oceans.
7/15/2019

Salish Sea Model looks at climate impacts on the nearshore

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.

11/15/2018

LiveOcean: Pacific Northwest ocean and estuary forecasts

LiveOcean is a computer model simulating ocean water properties in Puget Sound and the Pacific Northwest. It is produced by the University of Washington Ocean Modeling Group and makes three-day forecasts of currents, temperature, salinity and many biogeochemical fields including harmful algal blooms.

Chinook salmon leaping at the Ballard Locks in Seattle. Photo: Ingrid Taylar (CC BY 2.0) https://www.flickr.com/photos/taylar/29739921130
7/16/2018

New studies on emerging threats to salmon

Chemicals, disease and other stressors can increase a salmon's chance of being eaten or reduce its ability to catch food. We wrap up our series on the Salish Sea Marine Survival Project with a look at some of the lesser-known, but still significant factors contributing to salmon declines in the Salish Sea.

A milky, turquoise, phytoplankton bloom in Hood Canal visible from space. Natural color MODIS image from Landsat 8 acquired July 24, 2016. Photo: NASA Earth Observatory https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=88454
3/6/2018

Does Puget Sound need a diet? Concerns grow over nutrients

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.

The Budd Inlet sewage treatment plant. Photo courtesy of LOTT Clean Water Alliance
3/6/2018

Sewage treatment plant in Olympia a leader in nitrogen removal

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.

The rapid growth of a red-orange algae, Noctiluca scintillans, dramatically colors the waters of Puget Sound near Edmonds on May 16, 2013. Such algae blooms have been seen more frequently in recent years. Photo: Jeri Cusimano via WA Ecology (CC BY-NC 2.0) https://www.flickr.com/photos/ecologywa/8744775119
2/28/2018

Dead plankton leave clues to a food-web mystery

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.

Image describing low oxygen "dead zones"; image courtesy of NOAA
2/26/2018

How the state assesses low oxygen in Puget Sound

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. 

Steller Sea Lion (Eumetopias jubatus). Photo by NOAA Fisheries.
12/18/2017

Year-round algal toxin exposure in free-ranging sea lions

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.

Puget Sound Marine Waters 2015 report cover
9/27/2016

2015 Puget Sound Marine Waters Overview

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.

2013 Swinomish Tribe clam bake. Photo: Copyright Northwest Treaty Tribes https://www.flickr.com/photos/nwifc/9517621153
8/31/2016

Clam hunger

Social scientists around the Salish Sea are predicting the effects of environmental change through the lens of culturally important foods.

Report cover for State of Knowledge: Climate Change in Puget Sound
11/16/2015

State of Knowledge: Climate Change in Puget Sound

A 2015 report from the University of Washington provides the most comprehensive assessment to date of the expected impacts of climate change on the Puget Sound region.

The float plane prepares to take off. Photo by Jeff Rice for the Encyclopedia of Puget Sound.
6/19/2013

About the Eyes Over Puget Sound monitoring program

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.