What Causes Sea Foam

The formation of Sea Foam is found in different coastal regions around the world, some places worse than others, intriguing many people that witness it. Sea Foam is considered a natural phenomenon but its occurrence can be due to human activities in certain parts of the world making it a toxic problem to residents living along the coast. How it’s developed is a bit of a mystery. What causes Sea Foam?

Sea Foam, also called ocean & beach foam is created by the agitation of seawater close to shore, particularly when it contains high concentrations of dissolved organic matter. The foam is formed by air, water, and a key third ingredient called a surfactant that is derived from sources offshore.

Seafoam is a global phenomenon and it varies depending on location and the potential influence of the surrounding marine, freshwater, and/or terrestrial environments. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beach face inland and can cause some trouble to coastal dwellers filling city streets with blankets of foam.


How Does Seafoam Form

When high concentrations of decay accumulate in the oceans happens they usually end up washing up and look like a brown or reddish type of foam in the surf. Large amounts of decaying algal matter often wash ashore. Foam forms as this organic matter are churned up by the surf. Sometimes referred to as the ‘Red Tide’ it can be caused by the presence of waste products created by human activities. In order for foam to form, you need air, water, and a key third ingredient called a surfactant.

A Surfactant a kind of sticky molecule that clings to the surface between water and air. This molecule is man-made and comes from fertilizers, industrial waste, and even sewage in the ocean. All Surfactants have one thing in common. It’s that

  • One end of the molecule is hydrophilic which means it’s attracted to water
  • The other end of the molecule is hydrophobic which means it’s repelled by water.


Air can be trapped inside these waste product proteins, fats, dead algae, and form bubble close to the shore brought in by tides, currents, or wind, which stick to each other through surface tension.

Red tide is a phenomenon when a large population of phytoplankton, a single-celled plant, grows very fast or “blooms” and accumulates into dense, visible patches near the water surface. Nutrient pollution along with higher water temperature can fuel this colored foaming. Red color happening more in marine or seawater. Researchers say that the presence of the single-celled alga – phytoplankton – can cause the foam to take the reddish or brownish hue blue-green algae.

Cyanobacteria mainly occur in freshwater bodies and are a type of photosynthetic bacteria also known as blue-green algae, which are often the cause of algal blooms in freshwater and occasionally in marine water.

There are two kinds of Ocean Foams that can be formed – the White Seafoam and the Reddish-Brown colored foam that is churned up in the surf zone and blown inland where the waves are at their strongest. Essentially Sea Foam is totally natural and is not a big event compared to other natural occurrences.

Sea Foam can contain pollution or contaminants from Sewer or Stormwater drains that are in the vicinity of the blankets of Seafoam that are accumulated and end on the beach.


What Color is Seafoam

Foam on the sea excluding these causes is white in tinge. Single-celled alga which is powdered finely is regarded to be the causation of the white sea foam-forming as their powdery substance emanates sea foam-forming protein which in turn results in in in the formation of foam. The disruption of the surface tension allows for air to mix with the water and form bubbles. The foam can be different colors depending on the surfactant, which can contain detergents and soap.


  • Decomposing or decomposed materials from the seas like plants, animals, and excreta are churned by the continuous movement of the tides and form cloistered bubbles of air, are retained beneath the sea waves, and are whipped towards the shore and pulled by currents. These waves are frothy and when they crash against the shore, the froth at the top is left behind which causes the foamy effect
  • Alternatively, single-celled alga which is powdered finely is regarded to be the causation of the white sea foam-forming as their powdery substance emanates sea foam-forming protein which in turn results in the formation of foam
  • Chemical waste discharges by industries and sewerage into the oceans and seas also cause such foam to be formed on the sea


Is Sea Foam Toxic


In Southeast Queen’s land Australia Seafoam has become more than a natural occurrence at certain times of the year. The foaming from their coastal towns has made its way from the surf to the beach to inside city streets where this phenomenon has become a danger to its residents and wildlife. Most Sea Foam is not harmful and is often a sign of a healthy ecosystem. Still, when large healthy alga blooms decay too close to shore they have the potential for a negative impact on human health and the environment.

During these events, the Seafoam creates bubbles that become airborne. Toxins from alga blooms involved with Sea Foam bubbles can release them in an aerosol form. This form can have effects on people with chronic respiratory illnesses like asthma or can irritate the eyes of beachgoers and poses a health risk for children and pets.

Along Gulf coast beaches during blooms of Karenia brevis, for example, popping sea foam bubbles are one way that algal toxins become airborne. The resulting aerosol can irritate the eyes of beach goers and poses a health risk for those with asthma or other respiratory conditions.

Scientists studying the cause of a seabird die-offs off California in 2007 and in the Pacific Northwest in 2009 also found a soap-like foam from a decaying Akashiwo sanguinea algae bloom had removed the waterproofing on feathers, making it harder for birds to fly. This led to the onset of fatal hypothermia in many birds.   From the article –Attack of the Sea Foam, It’s Not Whale Sperm-2019 -Craig McClain is the Executive Director of the Lousiana University Marine Consortium. 


The presence of Seafoam could be dangerous as it contains noxious substances that could harm not only the local population but also the birds and other creatures. This could result in health problems and also problems pertaining to the presence of other harmful creatures that could hide in this froth and cause irreparable damage to the natives. I had no idea how serious this Sea foaming is too populated coastline communities until the video shows just how bad the problem is.



Before you start playing in the Ocean Foam which is kinda tempting when you see it, understand that it could be dangerous. This mixing of impurities in the ocean like salts, chemicals, pollution, dead plants, decomposed fish, normal seaweed excretions, copepod poo, and just about everything fantastic in the ocean creates bubbles that stick together and form the foam. The layers of foam don’t contain the wale sperm that is mentioned in the article.


Still, Researchers say that the foam contains ingredients of decaying algal blooms that concentrated and become aerosol that is not very healthy to breathe or have long contact with skin and recommend that as fun as it might be for you or pet dog to run around in for a while that it might be safer to keep the playtime at a minimum.

Algae are a beneficial part of natural environments and only a few are harmful but what’s in the Sea Foam is still a mystery and not worth gambling with the possible health issues. Read more about this phenomenon in another article from MyWaterEarth&Sky called Is Sea Foam Dangerous?




JimGalloway Author/Editor




National Oceanic & Atmospheric Administration

Chemistry WorldFrothed at sea






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