SEAFOAM: An unexpected hazard


Last month a sudden and tragic event involving an extreme case of sea foam shocked the Dutch surf community and claimed the lives of five surfers. In response to this event, experts at Surfrider Europe had a closer look at sea foam also known as “spume”. What are the health risks today?  

“Cappucino Coast”

Although the event in the Netherlands caught the surf community by surprise, heavy foam occurrences like this are not a new phenomenon. In many parts of the globe including coastal stretches of the U.S., Scotland, and Eastern Australia, sea foam or ‘spume’ has been documented completely covering city streets in some bizarre videos online after heavy storms, an event characterized by the term “Cappuccino Coast.” Instances of foam have also been found around lakes and rivers.  

Foam science

Surfrider’s beachapedia explains that sea foam is created when wind or waves stir up seawater that contains high concentrations of dissolved organic matter (proteins, fats, dead algae). In an environment like a surf zone close where waves break regularly, these substances act as foaming agents, trapping air under turbulent conditions and forming persistent bubbles which stick to each other through surface tension. Due to its low density and persistence, foam can be blown by strong onshore winds from nearshore waters onto the beach. Algal blooms are a common source of thick sea foams due to the large amount of dissolved organic matter. The nutrient matter found in algal blooms is usually from fertilizer and animal agriculture runoff. The presence of this matter, combined with an abundance of sunlight and high wind, can create extreme foam conditions.  

Sea foam can hold algal toxins or surface-active pollutants in its bubbles which release into the air and may cause irritation to eyes or pose a health risk for those with pre-existing respiratory health conditions. While there is no scientific evidence to suggest that sea foam increases a risk of drowning, one resource suggests that foam can become so thick, that in some extreme cases it poses an additional risk to children.  


Early this month, the Royal Netherlands Institute for Sea Research (NIOZ) released a report stating that: “The metres high seafoam during the fatal accident involving five surfers on 11 May in Scheveningen most probably arose due to an exceptional combination of many algal remains and, for this time of the year, an unusually strong north-northeasterly wind ... At present, the scientists advise providing information and training to lifeguards and people who practise water sports, because the development of a sufficiently automated warning system will take more time.”

What do we know about the type of foam?

Scientists at NIOZ tested foam samples collected on the day of the event and found large Phaeocystis Globose algae colony remains in high amounts never before recorded. The week before the incident was very sunny, providing the algae with a perfect environment to flourish. On May 10th, heavy clouds blew in which caused the algae colonies to die off and release their protein to create extreme amounts of foam.   

Looking back into their database of satellite images and weather patterns, NIOZ found that the conditions for high foam events occur annually between April and May. From this study, we can conclude that ocean users in this area of the Netherlands should take special care in Spring while there are strong onshore winds. 

What don't we know about Phaeocystis Globose?

Increased preventative measures over the past several years have led to a decrease in algal blooms caused by nutrient runoff reaching the North Sea. However, according to NIOZ, the Phaeocystis Globose algae has defied this trend and remains extremely present in large colonies. Does the Phaeocystis Globose feed on other nutrients that we are not yet aware of? Was this unprecedented bloom an isolated incident or can we expect more events like these in the future? Research on Phaeocystis Globose and their part in the foam event, and predictability of future events is still ongoing. In addition, it still has not been officially confirmed how the foam played a role in the five casualties in the Netherlands. Both of these uncertainties will be monitored by Surfrider Europe, and updated in this article as soon as we have it.  

In small amounts, seafoam should not pose any danger to ocean users. However, this horrible loss reminds us that there are no rules in nature and abnormalities can occur at any time. Always check your local water quality, currents and other hazards before entering the ocean and be especially vigilant of high sea foam events during Spring season. To help reduce nutrient runoff and preserve water quality in your local area, please have a look at our Ocean Friendly Garden project

Our deepest condolences to the family and friends of the surfers, as well as the surf community in the Netherlands.

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