Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter (including proteins, lignins, and lipids) derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. As the seawater is churned by breaking waves in the surf zone adjacent to the shore, the presence of these surfactants under these turbulent conditions traps air, forming persistent bubbles that stick to each other through surface tension. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beachface inland.
Where polluted stormwater from rivers or drains discharges to the coast, sea foam formed on adjacent beaches can be polluted with viruses and other contaminants, and may have an unpleasant odour.
If crude oil discharged from tankers at sea, or motor oil, sewage and detergents from polluted stormwater are present, the resulting sea foam is even more persistent, and can have a chocolate mousse texture.
If the foam forms from the breakdown of a harmful algal bloom (including those caused by some dinoflagellates and cyanobacteria), direct contact with the foam, or inhalation of aerosols derived from the foam as it dries, can cause skin irritations or respiratory discomfort.
On rare occasions large amounts of sea foam up to several metres thick can accumulate at the coast and constitute a physical hazard to beach users, through concealing large rocks and voids, storm debris and, in northern New South Wales, even sea snakes.
Notable occurrences 
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- A large buildup of sea foam occurred on the coast of Yamba, northern New South Wales, on 24 August 2007, and attracted world-wide media attention.
- Other sea foam occurrences at Caloundra and Point Cartwright, , on Queensland's Sunshine Coast in January–February 2008, also attracted world-wide media attention.
- During live coverage of Hurricane Irene in Ocean City, Maryland, Tucker Barnes was covered in sea foam.
- In December 2011, the coast road at Cleveleys, Lancashire was swamped by metre high drifts of sea foam.
- Following storms and high winds on 24/25 September 2012, the beach front of the Footdee area of Aberdeen was engulfed with sea foam.
- Between 27 and 28 January 2013, the Sunshine Coast in Queensland, Australia, had masses of foam wash up on land from ex-tropical cyclone Oswald.
See also 
- Spume Island
- Books about sea foam
- Nocturne, Opus 1: Sea Foam, Norene Moskalski. Divinity Press, October 2012. ISBN 978-0-988-38117-9; Library of Congress 2012950579
- James G. Acker, What is that foam in the surf? CoastalBC.com. Accessed 5 November 2010
- Jon Atkins, Warnings on sea foam on beaches, ABC North Coast: Emergency, 24 May 2009. Accessed 5 November 2010
- A. Lander, The foam is back!, Sunshine Coast Daily, 20 February 2008. Accessed 5 November 2010
- Sam Benger, Murky foam has residents in lather, Sunshine Coast Daily, 17 January 2008.
- Samantha Williams, Yamba hit by foam lather, The Daily Telegraph, 27 August 2007. Accessed 5 November 2010
- Richard Shears, Cappuccino Coast: The day the Pacific was whipped up into an ocean of froth, Mail Online, 28 August 2007. Accessed 5 November 2010
- Eric Shackle, Australia Foams at the Mouth, OhmyNews, 26 January 2008. Accessed 5 November 2010
- Brett M.Christensen, Whipped Ocean – Beach Foam at Yamba New South Wales, Hoax-Slayer.com, August 2008. Accessed 5 November 2010
- A. Lander, No place like foam Sunshine Coast Daily, 24 January 2008. Accessed 5 November 2010
- Mark Furler, Foam a global hit, Sunshine Coast Daily, 26 January 2008. Accessed 5 November 2010
- "FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City". Fox 5.[dead link]
- "Sea foam swamps cars at seaside resort of Cleveleys". BBC News. 29 December 2011. Retrieved 30 November 2012.
- "Foam swept in as gales hit Scotland". BBC News. 28 September 2012. Retrieved 30 November 2012.
- "Sunshine Coast Winter Wonderland". 28 January 2013. Retrieved 28 January 2013. Unknown parameter
- April 2007 Storm Photo Gallery Lane Memorial Library, Hampton, New Hampshire. Accessed 5 November 2010
- How foam forms on ocean waves Newscientist.com, Issue 1837, 5 September 1992. Article preview. Accessed 5 November 2010
- Blanket of white foam covers Aberdeen coast - Guardian video. Accessed 25 September 2012