Sea foam

For other uses, see Sea foam (disambiguation).

Sea foam in San Francisco.

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)^[1] 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 which 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 onto sidewalks and streets.

Hazards

Close-up of sea foam on a tide pool

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.^[2]

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,^[2][3] and may have an unpleasant odour.^[4]

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.^[3]

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 the foam as it dries, can cause skin irritations or other respiratory discomfort.^[1][2]

Notable occurrences

A large buildup of sea foam occurred on the coast of Yamba, northern New South Wales, 29°26′S 153°21′W / 29.433°S 153.35°W / -29.433; -153.35 on 24 August 2007, and attracted world-wide media attention.^[5][6][7][8]

Other sea foam occurrences at Caloundra 26°48′S 153°08′E / 26.8°S 153.133°E / -26.8; 153.133 and Point Cartwright, 26°40′47.8″S 153°08′18.1″E / 26.679944°S 153.138361°E / -26.679944; 153.138361, on Queensland's Sunshine Coast in January–February 2008, also attracted world-wide media attention.^[3][9][10]

During live coverage of Hurricane Irene in Ocean City, Maryland, Tucker Barnes was covered in sea foam.^[11]

See also

• Spume Island

References

1. ^ ^{a b} James G. Acker, What is that foam in the surf? CoastalBC.com. Accessed 5 November 2010
2. ^ ^{a b c} Jon Atkins, Warnings on sea foam on beaches, ABC North Coast: Emergency, 24 May 2009. Accessed 5 November 2010
3. ^ ^{a b c} A. Lander, The foam is back!, Sunshine Coast Daily, 20 February 2008. Accessed 5 November 2010
4. ^ Sam Benger, Murky foam has residents in lather, Sunshine Coast Daily, 17 January 2008.
5. ^ Samantha Williams, Yamba hit by foam lather, The Daily Telegraph, 27 August 2007. Accessed 5 November 2010
6. ^ 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
7. ^ Eric Shackle, Australia Foams at the Mouth, OhmyNews, 26 January 2008. Accessed 5 November 2010
8. ^ Brett M.Christensen, Whipped Ocean – Beach Foam at Yamba New South Wales, Hoax-Slayer.com, August 2008. Accessed 5 November 2010
9. ^ A. Lander, No place like foam Sunshine Coast Daily, 24 January 2008. Accessed 5 November 2010
10. ^ Mark Furler, Foam a global hit, Sunshine Coast Daily, 26 January 2008. Accessed 5 November 2010
11. ^ FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City

External links

• 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