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Link to sea spray sandbox: [[User:Vickeroodle/SandboxSeaSpray]]
[[File:Sea spray sea foam connection.png|thumb|Connection between sea foam and sea spray formation. The dark orange line indicates the processes that are common to formation of both sea spray and sea foam.]]

[[File:Sea spray sea foam connection.png|thumb|Sea spray sea foam connection]]


For other uses, see [[Sea foam (disambiguation)]].
For other uses, see [[Sea foam (disambiguation)]].


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)[21] derived from sources such as the offshore breakdown of algal blooms<sup>[1]</sup>. 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. Sea foam is a global phenomenon [21], and populations of sea foam vary depending on their location and the potential influence of the surrounding marine, freshwater, and/or terrestrial environments [27]. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beachface inland.
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''' (21). 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 surfactants under these turbulent conditions trap air, forming persistent '''bubbles''' that stick to each other through '''surface tension'''. Sea foam is a global phenomenon (21) and it varies depending on location and the potential influence of the surrounding marine, freshwater, and/or terrestrial environments [27]. Due to its low density and persistence, foam can be blown by strong on-shore winds from the '''beach face''' inland.


== Formation ==
== Formation ==
Sea foam is formed under conditions that are favorable for formation of sea spray, but one of the main distinctions from sea spray formation is the presence of higher concentrations of dissolves organic matter from macrophytes and phytoplankton. The dissolved organic matter in surface water provides some stability to the resulting sea foam [29]. The physical processes that are common to the formation of sea spray and sea foam are breaking of surface waves, and related phenomena like bubble entrainment and whitecap formation. Breaking of surface waves leads to entrainment of bubbles in the water column, the bubbles in the water column get transported around the top few meters of the surface ocean due to buoyancy effects. Smallest of the bubbles entrained in the water column dissolve entirely leading to higher ratios of dissolved gases in the wave affected surface ocean. The bubbles that do not dissolve eventually make it back to the surface, while traveling to the surface these bubbles accumulate hydrophobic substances. Once at the surface the bubble thins and eventually bursts releasing a slew sea spray into the atmosphere. Presence of dissolved organic matter stabilizes the bubble and these stabilized bubbles aggregates are together called as sea foam. Sometimes the sources of the sea foam is from the surrounding terrestrial vegetation [21]. Since wave breaking is one of the first steps in the formation of sea foam, there is an increased abundance of sea foam in the high winds condition [27]. Rain drops falling on the sea surface are one of the least studied mechanisms of sea spray and sea foam formation, these falling rain drops can lead to breaking of the sea surface into sprays and foam [cite Veron paper]. Thus there have been some non-mechanistic studies demonstrating increased sea foam formation due to high rainfall events [27]. Turbulence in the surface mixed layer can affect the concentration of dissolved organic matter and thus aid in the formation of nutrient-dense foam that is high in concentration of particulate organic matter [28]. Some studies on sea foam report that breaking of algal cells in times of heavy swells adds to the likelihood of sea foam production [29].
Sea foam is formed under conditions that are similar to the formation of '''sea spray'''. One of the main distinctions from sea spray formation is the presence of higher concentrations of dissolved organic matter from '''macrophytes''' and '''phytoplankton'''. The dissolved organic matter in the surface water, which can be derived from the natural environment or human-made sources, provides stability to the resulting sea foam [29]. The physical processes that contribute to sea foam formation are breaking '''surface waves''', '''bubble entrainment,''' and '''whitecap formation'''. Breaking of surface waves injects air from the atmosphere into the water column, leading to bubble creation. These bubbles get transported around the top few meters of the surface ocean due to their '''buoyancy'''. The smallest bubbles entrained in the water column dissolve entirely leading to higher ratios of dissolved gases in the surface ocean. The bubbles that do not dissolve eventually make it back to the surface. As they rise, these bubbles accumulate '''hydrophobic''' substances. Presence of dissolved organic matter stabilizes the bubbles, aggregating together as sea foam (21). Some studies on sea foam report that breaking of algal cells in times of heavy swells makes sea foam production more likely [29].

Falling rain drops on the sea surface can also contribute to sea foam formation and destruction <sup>[Veron paper]</sup>. There have been some non-mechanistic studies demonstrating increased sea foam formation due to high rainfall events [27]. Turbulence in the '''surface mixed layer''' can affect the concentration of dissolved organic matter and aids in the formation of nutrient-dense foam [28].


== Composition ==
== Composition ==
The composition of sea foam is generally a mixture of decomposed organic materials, including '''zooplankton''', '''phytoplankton''', '''algae''' (including '''diatoms'''<sup>[[User:Vickeroodle/SandboxSeaFoam#cite%20note-1|[3]]]</sup> [23]), '''bacteria''', '''fungi''', '''protozoans''', and plant matter, though each occurrence of sea foam varies in its specific contents. In some areas, sea foam is found to be made up of 22.85% '''protein''', dominant in both fresh and old foam, 10.76% '''lipids''', and 3.07% '''carbohydrates'''. The high protein and low carbohydrate concentration suggest that '''sugars''' originally present in the surrounding mucilage created by algae or plant matter has been quickly consumed by bacteria. [29] Additional research has shown that between 0.05% and 0.16% of sea foam measured by dry weight is '''organic carbon,''' which contains '''phenolics''', sugars, '''amino sugars''', and '''amino acids'''. In the '''Bay of Fundy''', high mortality rates of an abundant tube-dwelling '''amphipod''' (''Corophium volutator)'' by natural die-offs as well as predation by migrating seabirds contributed to amino sugars released in the surrounding environment and thus, in sea foam. [28] It is thought that the carbon in sea foam is primarily derived from '''vascular plant''' detritus. [28] The organic matter in sea foam has been found to increase dramatically during '''phytoplankton blooms''' in the area. [19]
The composition of sea foam is generally a mixture of decomposed organic materials, including '''zooplankton''', '''phytoplankton''', '''algae''' (including '''diatoms'''<sup>[[User:Vickeroodle/SandboxSeaFoam#cite%20note-1|[3]]]</sup> [23]), '''bacteria''', '''fungi''', '''protozoans''', and vascular plant '''detritus''' (28), though each occurrence of sea foam varies in its specific contents. In some areas, sea foam is found to be made up of primarily '''protein''', dominant in both fresh and old foam, as well as '''lipids''' and '''carbohydrates'''. The high protein and low carbohydrate concentration suggest that '''sugars''' originally present in the surrounding mucilage created by algae or plant matter has been quickly consumed by bacteria. [29] Additional research has shown that between a small fraction of sea foam measured by dry weight is '''organic carbon,''' which contains '''phenolics''', sugars, '''amino sugars''', and '''amino acids'''. In the '''Bay of Fundy''', high mortality rates of an abundant tube-dwelling '''amphipod''' (''Corophium volutator)'' by natural die-offs as well as predation by migrating seabirds contributed to amino sugars released in the surrounding environment and thus, in sea foam. [28]


Some research has shown very high concentrations of '''microplankton''' in sea foam, with significantly higher numbers of '''autotrophic''' phytoplankton than '''heterotrophs'''. [23] Some foams are particularly rich in their diatom population which can make up 80.1-96.3% of the microalgal '''biomass''' in some cases<sup>[3]</sup>. [23] A diversity of bacteria is also present in sea foam; old foam tends to have a higher density of bacteria. One study found that 95% of sea foam bacteria was rod-shaped, while the surrounding surface water contained mostly coccoid-form bacteria and only 5% - 10% rod-shaped bacteria. [29] There is also seasonal variability of sea foam composition [28]; in some regions there is a seasonal occurrence of pollen in sea foam which can alter its chemistry. [27] Though foam is not inherently toxic, it may contain high concentrations of contaminants. [21] The boundary layer between the air and ocean surface ('''surface microlayer''', or SML) is a place where materials that will not be absorbed further into the water column gather. Foam bubbles can be coated with or contain these materials which can include '''petroleum compounds''', '''pesticides''', and '''herbicides'''. [21]
The organic matter in sea foam has been found to increase dramatically during '''phytoplankton blooms''' in the area. [19] Some research has shown very high concentrations of '''microplankton''' in sea foam, with significantly higher numbers of '''autotrophic''' phytoplankton than '''heterotrophs'''. [23] Some foams are particularly rich in their diatom population which can make up the majority of the microalgal '''biomass''' in some cases. [23] A diversity of bacteria is also present in sea foam; old foam tends to have a higher density of bacteria. One study found that 95% of sea foam bacteria was '''rod-shaped''', while the surrounding surface water contained mostly '''coccoid-form''' bacteria and only 5% - 10% rod-shaped bacteria. [29] There is also seasonal variability of sea foam composition [28]; in some regions there is a seasonal occurrence of pollen in sea foam which can alter its chemistry. [27] Though foam is not inherently toxic, it may contain high concentrations of contaminants. [21] Foam bubbles can be coated with or contain these materials which can include '''petroleum compounds''', '''pesticides''', and '''herbicides'''. [21]


== Longevity and stability ==
== Longevity and stability ==
Structurally, sea foam is '''thermodynamically''' unstable, though some sea foam can persist in the environment for several days at most. There are two types of sea foam categorized based on their stability: 1) Unstable or transient foams have very short lifetimes of only seconds. The bubbles formed in sea foam may burst releasing aerosols into the air, contributing to '''sea spray'''. 2) Metastable foams can have a lifetime of several hours to several days; their duration is sometimes attributed to small particles of '''silica''', '''calcium''', or '''iron''' which contribute to foam stability and longevity. [21] Additionally, seawater that contains released dissolved organic material from phytoplankton and macrophytic algae that is then agitated in its environment is most likely to produce stable, longer-lasting foam when compared with seawater lacking one of those components. For example, filtered seawater with added with the fronds of the '''kelp''', ''Ecklonia maxima,'' produced foam but it lacked the stability that unfiltered seawater provided. Additionally, kelp fronds that were maintained in flowing water therefore reducing their mucus coating, were unable to help foam form. [29] Different types of salt are also found to have varying effects on bubble proximity within sea foam, therefore contributing to its stability. [21]
Structurally, sea foam is '''thermodynamically''' unstable, though some sea foam can persist in the environment for several days at most. There are two types of sea foam categorized based on their stability: 1) Unstable or transient foams have very short lifetimes of only seconds. The bubbles formed in sea foam may burst releasing aerosols into the air, contributing to '''sea spray'''. 2) Metastable foams can have a lifetime of several hours to several days; their duration is sometimes attributed to small particles of '''silica''', '''calcium''', or '''iron''' which contribute to foam stability and longevity. [21] Additionally, seawater that contains released dissolved organic material from phytoplankton and macrophytic algae that is then agitated in its environment is most likely to produce stable, longer-lasting foam when compared with seawater lacking one of those components. For example, filtered seawater with added with the fronds of the '''kelp''', ''Ecklonia maxima,'' produced foam but it lacked the stability that unfiltered seawater provided. Additionally, kelp fronds that were maintained in flowing water therefore reducing their '''mucus''' coating, were unable to help foam form. [29] Different types of salt are also found to have varying effects on bubble proximity within sea foam, therefore contributing to its stability. [21]


== Ecological role ==
== Ecological role ==


=== '''Food Source''' ===
=== '''Food Source''' ===
The presence of sea foam in the marine environment plays a number of ecological roles including providing sources of food and creating habitat. As a food source, sea foam with a stable composition is more important ecologically, as it is able to persist longer and can transport nutrients within the marine environment. [29] Longer decay times result in a higher chance that energy contained in sea foam will move up the food web into higher '''trophic levels'''. [29] In the Bay of Fundy, for example, a tube-dwelling '''amphipod''', ''Corophium volutator,'' can potentially attain 70% of its nutritional requirements from the sugars and amino acids derived from sea foam in its environment. At times, however, the sea foam was found to be toxic to this species. It is thought that high concentrations of '''phenolics''' and/or the occasional presence of heavy metals or pesticides incorporated into the sea foam from the sea surface contributed to its toxicity. [28] On the west coast of '''Cape Peninsula''', '''South Africa''', sea foam often occurs in nearshore marine areas with large kelp beds during periods of strong westerly winds. It is thought that the foam generated in these conditions is an important food source for local organisms due to the presence of organic '''detritus''' in the sea foam. [29]
The presence of sea foam in the marine environment plays a number of ecological roles including providing sources of food and creating habitat. As a food source, sea foam with a stable composition is more important ecologically, as it is able to persist longer and can transport nutrients within the marine environment. [29] Longer decay times result in a higher chance that energy contained in sea foam will move up the food web into higher '''trophic levels'''. [29] In the Bay of Fundy for example, a tube-dwelling '''amphipod''', ''Corophium volutator,'' can potentially attain 70% of its nutritional requirements from the sugars and amino acids derived from sea foam in its environment. At times however, the sea foam was found to be toxic to this species. It is thought that high concentrations of '''phenolics''' and/or the occasional presence of heavy metals or pesticides incorporated into the sea foam from the sea surface contributed to its toxicity. [28] On the west coast of '''Cape Peninsula''', '''South Africa''', sea foam often occurs in nearshore marine areas with large kelp beds during periods of strong westerly winds. It is thought that the foam generated in these conditions is an important food source for local organisms due to the presence of organic '''detritus''' in the sea foam. [29]


=== '''Material Transport''' ===
=== '''Material Transport''' ===
It also acts as a mode of transport for both organisms and nutrients within the marine environment and, at times, into the '''intertidal''' or terrestrial environments. Wave action can deposit foam into intertidal areas where it can remain when the tide recedes, bringing nutrients to the intertidal zone. [28] Additionally, sea foam can become airborne in windy conditions, resulting in '''sea spray''' and therefore serving as a mode of transport for materials between marine and terrestrial environments. [27] The ability of sea foam to transport materials is also thought to benefit '''macroalgal''' organisms, as macroalgae propagules can be carried to different microenvironments, thus influencing the tidal landscape and contributing to new possible ecological interactions. [20] As sea foam is a wet environment, it is conducive habitat to algal spores where propagules can attach and advect to the substrate and avoid risk of dissemination. [20] When sea foam contains fungi, it can also aid in the decomposition of plant and animal remains in coastal ecosystems. [27]
Sea foam also acts as a mode of transport for both organisms and nutrients within the marine environment and, at times, into the '''intertidal''' or terrestrial environments. Wave action can deposit foam into intertidal areas where it can remain when the tide recedes, bringing nutrients to the intertidal zone. [28] Additionally, sea foam can become airborne in windy conditions, transporting materials between marine and terrestrial environments. [27] The ability of sea foam to transport materials is also thought to benefit '''macroalgal''' organisms, as macroalgae propagules can be carried to different microenvironments, thus influencing the tidal landscape and contributing to new possible ecological interactions. [20] As sea foam is a wet environment, it is conducive habitat to algal spores where '''propagules''' can attach to the substrate and avoid risk of '''dissemination'''. [20] When sea foam contains fungi, it can also aid in the decomposition of plant and animal remains in coastal ecosystems. [27]

=== '''Habitat''' ===
Additionally, sea foam is a habitat for a number of marine '''microorganisms'''. Some research has shown the presence of various microphytoplanktonic, nanophytoplanktonic, and diatom groups in seafoam; the phytoplankton groups appeared in significantly higher abundance than in sea surface film and the top '''pelagic zone'''. [23]


== Hazards ==
== Hazards ==
=== Toxicity ===
=== Toxicity ===
Naturally occurring sea foam is not inherently toxic; however, it can be exposed to high concentrations of contaminants in the '''sea surface microlayer''' derived from the breakdown of algal blooms, fossil fuel production and transport, and stormwater runoff (21). These contaminants contribute to the formation of noxious sea foam through '''adsorption''' onto bubbles in the surface layer. Bubbles may burst and release toxins into the atmosphere in the form of '''sea spray''' or aerosol, or they may persist in foams. Toxins released through aerosols and breaking of bubbles as foams degrade can be inhaled by humans. The microorganisms that occupy sea foams as habitat have increased susceptibility for contaminant exposure (38). Consequently, these toxic substances can be integrated into the trophic food chain (21).
Naturally occurring sea foam is not inherently '''toxic'''; however, it can be exposed to high concentrations of contaminants in the '''surface microlayer''' derived from the breakdown of algal blooms, fossil fuel production and transport, and stormwater runoff (21). These contaminants contribute to the formation of noxious sea foam through '''adsorption''' onto bubbles. Bubbles may burst and release toxins into the atmosphere in the form of sea spray or '''aerosol''', or they may persist in foams. Toxins released through aerosols and breaking bubbles can be inhaled by humans. The microorganisms that occupy sea foams as habitat have increased susceptibility for contaminant exposure (38). Consequently, these toxic substances can be integrated into the trophic '''food web''' (21).

==== Harmful algal blooms ====
Foams can form following the degradation of '''harmful algal blooms''' (HABs), primarily composed of algal species, but can also consist of dinoflagellates and cyanobacteria (30). Sea foam serves as a critical wet environment for algal spores where propagules can attach to bubbles (20). Biomass from algae in the bloom is integrated into sea foam in the '''sea surface microlayer''' (19). When the impacted sea foam deteriorates, toxins from the algae are released into the air causing breathing issues and occasionally initiating asthma attacks (37).


=== '''Harmful algal blooms''' ===
''Phaeocystis globosa'' is one algal species that is considered problematic. Its high biomass accumulation allows it to create large quantities of toxic foam that often wash onto beaches (30). ''P. globosa'' blooms are initiated in areas of high nutrient availability, often affiliated with coastal locations with a lot of freshwater or stormwater runoff, and eutrophication. Studies suggest that the development of foam is directly correlated to blooms caused by ''P. globosa'', despite that foam formation typically occurs approximately two weeks after the appearance of an algal bloom offshore (30). Organic material from ''P. globosa'' was observed decomposing while suspended at the sea surface, but was not observed lower in the water column. ''P. globosa'' is also considered a nuisance species whose large foam formations impairs the public’s ability to enjoy the beach (30).
Foams can form following the degradation of '''harmful algal blooms''' (HABs). These are primarily composed of algal species, but can also consist of '''dinoflagellates''' and '''cyanobacteria''' (30). Biomass from algae in the bloom is integrated into sea foam in the sea surface microlayer (19). When the impacted sea foam breaks down, toxins from the algae are released into the air causing respiratory issues and occasionally initiating asthma attacks (37). ''Phaeocystis globosa'' is one algal species that is considered problematic, as observed in a study in the Netherlands (30). Its high biomass accumulation allows it to create large quantities of toxic foam that often wash onto beaches. ''P. globosa'' blooms are initiated in areas of high nutrient availability, often affiliated with coastal locations with a lot of stormwater runoff and '''eutrophication'''. Studies suggest that the development of foam is directly correlated to blooms caused by ''P. globosa'', despite that foam formation typically occurs approximately two weeks after the appearance of an algal bloom offshore. Organic material from ''P. globosa'' was observed decomposing while suspended at the sea surface, but was not observed lower in the water column. ''P. globosa'' is also considered a nuisance species because its large foam formations impair the public’s ability to enjoy the beach (30).


==== Human activities ====
=== '''Human activities''' ===
While sea foam is a common result of the agitation of seawater mixing with organic material in the surface ocean, human activities can contribute to the production of excess and often toxic foam (21). In addition to the organic oils, acids, and proteins that amass in the '''sea surface microlayer''', compounds derived from petroleum production and transport, synthetic surfactants, and pesticide use can enter the sea surface and be incorporated into foam (21). The pollutants present can also affect the persistence of the foam produced. Crude oil discharged from tankers, motor oil, sewage, and detergents from polluted runoff can create longer-lasting foams (21). In one study, [[Polychlorinated biphenyl|polychlorinated biphenyls]] (PCBs), a persistent organic pollutant, were found to amass in sea foams (38).
While sea foam is a common result of the agitation of seawater mixing with organic material in the surface ocean, human activities can contribute to the production of excess and often toxic foam (21). In addition to the organic oils, acids, and proteins that amass in the '''sea surface microlayer''', compounds derived from petroleum production and transport, synthetic surfactants, and pesticide use can enter the sea surface and be incorporated into foam. The pollutants present can also affect the persistence of the foam produced. Crude oil discharged from tankers, motor oil, sewage, and detergents from polluted runoff can create longer-lasting foams (21). In one study, [[Polychlorinated biphenyl|polychlorinated biphenyls]] (PCBs), a persistent organic pollutant, were found to amass in sea foams (38).


'''Natural gas terminals''' have been cited as contributors to the production of modified foams due to the process of using seawater to convert natural gas to '''liquified natural gas''' (25). One study showed a much greater abundance of heterotrophic '''prokaryotes''' (archaea and bacteria) and cyanobacteria in foam that was generated near a liquified natural gas terminal. These prokaryotes were able to recycle chemical materials discharged from the terminal, which enhanced microbial growth (25). Additionally, higher levels of '''total organic carbon''' (TOC) and plankton biomass were recorded in foam generated in close proximity to the terminal. Organic carbon was transferred readily into the pelagic food web after uptake my prokaryotes and ingestion by grazers (25).
'''Natural gas terminals''' have been cited as contributors to the production of modified foams due to the process of using seawater to convert natural gas to '''liquified natural gas''' (25). One study showed a much greater abundance of heterotrophic '''prokaryotes''' (archaea and bacteria) and cyanobacteria in foam that was generated near a liquified natural gas terminal. These prokaryotes were able to recycle chemical materials discharged from the terminal, which enhanced microbial growth. Additionally, higher levels of '''total organic carbon''' (TOC) and plankton biomass were recorded in foam generated in close proximity to the terminal. Organic carbon was transferred readily into the pelagic food web after uptake my prokaryotes and ingestion by grazers (25).


== Notable occurrences ==
== Notable occurrences ==
Sea spray has frequently appeared in the literature and media, some interesteing instances of which include but are not limited to:
<nowiki>**</nowiki>Tori add news links, puppies, sea snakes, danger!


* January 2018: Storm Eleanor causes widespread foam to appear across coastal Europe. <ref>{{Cite web|url=https://www.bbc.co.uk/news/av/world-europe-42561598/dog-enjoys-beach-covered-in-sea-foam-caused-by-storm-eleanor|title=Eleanor whips up sea foam party for dog|website=BBC News|access-date=2018-01-04}}</ref>
* Southern Barents Sea, August 31, 1987 [23]
*12 December 2017 large amount of sea foam brought by thunderstorm and strong winds to the [[Ostia (Rome)|Ostia]] beach shore, in [[Rome]]. A rare event for the Mediterranean Sea.
* There is a notable summer occurrence of sea foam in the North Sea due to the presence of ''Phaeocystis cf. pouchetii,'' a phytoplankton species that produces a large quantity of mucilaginous material in the process of primary production. The mucus collects in a dissolved form and easily foams as it is polymeric in structure. There is an observed increase in the phenomenon as levels of nutrients such as nitrogen, phosphorus, and silica rise due to anthropogenic input.   [26]
*16 October 2017: [[Hurricane Ophelia]] covered [[Cleveleys]], [[Lancashire]] with spume.<ref>[https://www.independent.co.uk/news/uk/home-news/storm-ophelia-latest-news-hurricane-town-foam-weather-water-flooding-cleveleys-lancashire-a8004911.html#gallery] The Independent, 16 October 2017. Retrieved 18 October 2017.</ref>
* The water turns reddish-brown. Meters tall. Bätje and Michaelis (1986) [21]
*28 March 2017: sea foam brought by [[Cyclone Debbie]] at Sarina Beach in Queensland, Australia.<ref>{{Cite web|url=http://www.abc.net.au/news/2017-03-28/thick-sea-foam-rolls-onto-sarina-beach-during/8393836|title=Thick sea foam rolls onto Sarina Beach during Cyclone Debbie|date=28 March 2017|publisher=abc.net.au|accessdate=11 September 2017}}</ref>
* ** There are a lot more listed in [21]
*June 2016: sea foam occurred across the East coast of Australia, whipped up by storms.<ref>{{Cite web|url=http://www.abc.net.au/news/2016-06-07/sea-foam-whipped-up-by-storms-could-be-hazardous/7483750|title=East coast low: Sea foam whipped up by storms could be hazardous to health, toxicologist warns|date=7 June 2016|publisher=abc.net.au|accessdate=11 September 2017}}</ref>
** A large buildup of sea foam occurred on the coast of [[Yamba, New South Wales|Yamba, northern New South Wales]], {{coord|29|26|S|153|21|E|display=inline}} on 24 August 2007, and attracted world-wide media attention.<ref>Samantha Williams, [http://www.dailytelegraph.com.au/news/nsw-act/yamba-hit-by-foam-lather/story-e6freuzi-1111114272509 Yamba hit by foam lather], ''The Daily Telegraph'', 27 August 2007. Accessed 5 November 2010</ref><ref>Richard Shears, [http://www.dailymail.co.uk/news/article-478041/Cappuccino-Coast-The-day-Pacific-whipped-ocean-froth.html Cappuccino Coast: The day the Pacific was whipped up into an ocean of froth], ''Mail Online'', 28 August 2007. Accessed 5 November 2010</ref><ref>Eric Shackle, [http://english.ohmynews.com/articleview/article_view.asp?menu=c10400&no=381567&rel_no=1&isPrint=print Australia Foams at the Mouth], ''OhmyNews'', 26 January 2008. Accessed 5 November 2010</ref><ref>Brett M.Christensen, [http://www.hoax-slayer.com/whipped-ocean-foam.shtml Whipped Ocean – Beach Foam at Yamba New South Wales], ''Hoax-Slayer.com'', August 2008. Accessed 5 November 2010</ref>
*Between 27 and 28 January 2013, the [[Sunshine Coast, Queensland|Sunshine Coast]] in [[Queensland]], [[Australia]], had masses of foam wash up on land from ex-tropical cyclone [[2012–13 Australian region cyclone season#Tropical Cyclone Oswald|Oswald]].<ref>{{Cite web|url=http://news.ninemsn.com.au/national/2013/01/28/12/21/sunshine-coast-winter-wonderland|title=Sunshine Coast Winter Wonderland|date=28 January 2013|publisher=Ninemsn|archiveurl=https://web.archive.org/web/20130129144234/http://news.ninemsn.com.au/national/2013/01/28/12/21/sunshine-coast-winter-wonderland|archivedate=29 January 2013|url-status=dead|accessdate=28 January 2013}}</ref>
** Other sea foam occurrences at [[Caloundra]] {{coord|26|48|S|153|08|E|display=inline}} and [[Mooloolaba, Queensland|Point Cartwright]], {{coord|26|40|47.8|S|153|08|18.1|E|display=inline}}, on [[Queensland]]'s [[Sunshine Coast, Queensland|Sunshine Coast]] in January–February 2008, also attracted world-wide media attention.<ref name="Lander2">A. Lander, [http://www.sunshinecoastdaily.com.au/story/2008/02/20/foam-back/ The foam is back!], ''Sunshine Coast Daily'', 20 February 2008. Accessed 5 November 2010</ref><ref>A. Lander, [http://www.sunshinecoastdaily.com.au/story/2008/01/24/monster-deep-emerge-sea-foam/ No place like foam] ''Sunshine Coast Daily'', 24 January 2008. Accessed 5 November 2010</ref><ref>Mark Furler, [http://www.sunshinecoastdaily.com.au/story/2008/01/26/foam-global-hit/ Foam a global hit], ''Sunshine Coast Daily'', 26 January 2008. Accessed 5 November 2010</ref>
** During live coverage of [[Hurricane Irene]] in [[Ocean City, Maryland]], [[Tucker Barnes]] was covered in sea foam.<ref>{{Cite web|url=http://www.myfoxdc.com/dpp/weather/storm_chasers/tucker-barnes-braves-the-sea-foam-in-ocean-city-082711|title=FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City|publisher=Fox 5|archiveurl=https://web.archive.org/web/20120116043250/http://www.myfoxdc.com/dpp/weather/storm_chasers/tucker-barnes-braves-the-sea-foam-in-ocean-city-082711|archivedate=January 16, 2012|deadurl=yes}}</ref>
*Following storms and high winds on 24/25 September 2012, the beach front of the Footdee area of Aberdeen was engulfed with sea foam.<ref>{{Cite web|url=https://www.bbc.co.uk/news/uk-scotland-19710226|title=Foam swept in as gales hit Scotland|date=28 September 2012|publisher=BBC News|accessdate=30 November 2012}}</ref>
*During live coverage in 2012 of [[Hurricane Irene]] in [[Ocean City, Maryland]], [[Tucker Barnes]] was covered in sea foam.<ref>{{Cite web|url=http://www.myfoxdc.com/dpp/weather/storm_chasers/tucker-barnes-braves-the-sea-foam-in-ocean-city-082711|title=FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City|publisher=Fox 5|archiveurl=https://web.archive.org/web/20120116043250/http://www.myfoxdc.com/dpp/weather/storm_chasers/tucker-barnes-braves-the-sea-foam-in-ocean-city-082711|archivedate=January 16, 2012|url-status=dead}}</ref>
** In December 2011, the coast road at [[Cleveleys]], [[Lancashire]] was swamped by metre high drifts of sea foam.<ref>{{Cite web|url=https://www.bbc.co.uk/news/uk-england-lancashire-16354575|title=Sea foam swamps cars at seaside resort of Cleveleys|date=29 December 2011|publisher=BBC News|accessdate=30 November 2012}}</ref>
*In December 2011, the coast road at [[Cleveleys]], [[Lancashire]] was swamped by metre high drifts of sea foam.<ref>{{Cite web|url=https://www.bbc.co.uk/news/uk-england-lancashire-16354575|title=Sea foam swamps cars at seaside resort of Cleveleys|date=29 December 2011|publisher=BBC News|accessdate=30 November 2012}}</ref>
*Other sea foam occurrences at [[Caloundra]] {{coord|26|48|S|153|08|E|display=inline}} and [[Mooloolaba, Queensland|Point Cartwright]], {{coord|26|40|47.8|S|153|08|18.1|E|display=inline}}, on [[Queensland]]'s [[Sunshine Coast, Queensland|Sunshine Coast]] in January–February 2008, also attracted world-wide media attention.<ref name="Lander2">A. Lander, [http://www.sunshinecoastdaily.com.au/story/2008/02/20/foam-back/ The foam is back!], ''Sunshine Coast Daily'', 20 February 2008. Accessed 5 November 2010</ref><ref>A. Lander, [http://www.sunshinecoastdaily.com.au/story/2008/01/24/monster-deep-emerge-sea-foam/ No place like foam] ''Sunshine Coast Daily'', 24 January 2008. Accessed 5 November 2010</ref><ref>Mark Furler, [http://www.sunshinecoastdaily.com.au/story/2008/01/26/foam-global-hit/ Foam a global hit], ''Sunshine Coast Daily'', 26 January 2008. Accessed 5 November 2010</ref>
** Following storms and high winds on 24/25 September 2012, the beach front of the Footdee area of Aberdeen was engulfed with sea foam.<ref>{{Cite web|url=https://www.bbc.co.uk/news/uk-scotland-19710226|title=Foam swept in as gales hit Scotland|date=28 September 2012|publisher=BBC News|accessdate=30 November 2012}}</ref>
*A large buildup of sea foam occurred on the coast of [[Yamba, New South Wales|Yamba, northern New South Wales]], {{coord|29|26|S|153|21|E|display=inline}} on 24 August 2007, and attracted world-wide media attention.<ref>Samantha Williams, [http://www.dailytelegraph.com.au/news/nsw-act/yamba-hit-by-foam-lather/story-e6freuzi-1111114272509 Yamba hit by foam lather], ''The Daily Telegraph'', 27 August 2007. Accessed 5 November 2010</ref><ref>Richard Shears, [http://www.dailymail.co.uk/news/article-478041/Cappuccino-Coast-The-day-Pacific-whipped-ocean-froth.html Cappuccino Coast: The day the Pacific was whipped up into an ocean of froth], ''Mail Online'', 28 August 2007. Accessed 5 November 2010</ref><ref>Eric Shackle, [http://english.ohmynews.com/articleview/article_view.asp?menu=c10400&no=381567&rel_no=1&isPrint=print Australia Foams at the Mouth], ''OhmyNews'', 26 January 2008. Accessed 5 November 2010</ref><ref>Brett M.Christensen, [http://www.hoax-slayer.com/whipped-ocean-foam.shtml Whipped Ocean – Beach Foam at Yamba New South Wales], ''Hoax-Slayer.com'', August 2008. Accessed 5 November 2010</ref>
** Between 27 and 28 January 2013, the [[Sunshine Coast, Queensland|Sunshine Coast]] in [[Queensland]], [[Australia]], had masses of foam wash up on land from ex-tropical cyclone [[2012–13 Australian region cyclone season#Tropical Cyclone Oswald|Oswald]].<ref>{{Cite web|url=http://news.ninemsn.com.au/national/2013/01/28/12/21/sunshine-coast-winter-wonderland|title=Sunshine Coast Winter Wonderland|date=28 January 2013|publisher=Ninemsn|archiveurl=https://web.archive.org/web/20130129144234/http://news.ninemsn.com.au/national/2013/01/28/12/21/sunshine-coast-winter-wonderland|archivedate=29 January 2013|deadurl=yes|accessdate=28 January 2013|df=}}</ref>
*A notable summer occurrence of sea foam in the North Sea due to the presence of ''Phaeocystis cf. pouchetii,'' a phytoplankton species that produces a large quantity of mucilaginous material in the process of primary production. The mucus collects in a dissolved form and easily foams as it is polymeric in structure. There is an observed increase in the phenomenon as levels of nutrients such as nitrogen, phosphorus, and silica rise due to anthropogenic input.   [26]
** June 2016: sea foam across the East coast of Australia, whipped up by storms.<ref>{{Cite web|url=http://www.abc.net.au/news/2016-06-07/sea-foam-whipped-up-by-storms-could-be-hazardous/7483750|title=East coast low: Sea foam whipped up by storms could be hazardous to health, toxicologist warns|date=7 June 2016|publisher=abc.net.au|accessdate=11 September 2017}}</ref>
* Records of the ocean water turning reddish-brown and reaching heights of meters tall. Bätje and Michaelis (1986) [21]
** 28 March 2017: sea foam brought by [[Cyclone Debbie]] at Sarina Beach in Queensland, Australia.<ref>{{Cite web|url=http://www.abc.net.au/news/2017-03-28/thick-sea-foam-rolls-onto-sarina-beach-during/8393836|title=Thick sea foam rolls onto Sarina Beach during Cyclone Debbie|date=28 March 2017|publisher=abc.net.au|accessdate=11 September 2017}}</ref>
** 16 October 2017: [[Hurricane Ophelia]] covered [[Cleveleys]], [[Lancashire]] with spume.<ref>[https://www.independent.co.uk/news/uk/home-news/storm-ophelia-latest-news-hurricane-town-foam-weather-water-flooding-cleveleys-lancashire-a8004911.html#gallery] The Independent, 16 October 2017. Retrieved 18 October 2017.</ref>
** 12 December 2017 large amount of sea foam brought by thunderstorm and strong winds to the [[Ostia (Rome)|Ostia]] beach shore, in [[Rome]]. A rare event for the Mediterranean Sea.
** January 2018: Storm Eleanor causes widespread foam across Europe. <ref>{{Cite web|url=https://www.bbc.co.uk/news/av/world-europe-42561598/dog-enjoys-beach-covered-in-sea-foam-caused-by-storm-eleanor|title=Eleanor whips up sea foam party for dog|website=BBC News|access-date=2018-01-04}}</ref>


== References ==
== References ==
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Latest revision as of 21:30, 11 June 2022

Connection between sea foam and sea spray formation. The dark orange line indicates the processes that are common to formation of both sea spray and sea foam.

For other uses, see Sea foam (disambiguation).

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 (21). 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 surfactants under these turbulent conditions trap air, forming persistent bubbles that stick to each other through surface tension. Sea foam is a global phenomenon (21) and it varies depending on location and the potential influence of the surrounding marine, freshwater, and/or terrestrial environments [27]. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beach face inland.

Formation

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Sea foam is formed under conditions that are similar to the formation of sea spray. One of the main distinctions from sea spray formation is the presence of higher concentrations of dissolved organic matter from macrophytes and phytoplankton. The dissolved organic matter in the surface water, which can be derived from the natural environment or human-made sources, provides stability to the resulting sea foam [29]. The physical processes that contribute to sea foam formation are breaking surface waves, bubble entrainment, and whitecap formation. Breaking of surface waves injects air from the atmosphere into the water column, leading to bubble creation. These bubbles get transported around the top few meters of the surface ocean due to their buoyancy. The smallest bubbles entrained in the water column dissolve entirely leading to higher ratios of dissolved gases in the surface ocean. The bubbles that do not dissolve eventually make it back to the surface. As they rise, these bubbles accumulate hydrophobic substances. Presence of dissolved organic matter stabilizes the bubbles, aggregating together as sea foam (21). Some studies on sea foam report that breaking of algal cells in times of heavy swells makes sea foam production more likely [29].

Falling rain drops on the sea surface can also contribute to sea foam formation and destruction [Veron paper]. There have been some non-mechanistic studies demonstrating increased sea foam formation due to high rainfall events [27]. Turbulence in the surface mixed layer can affect the concentration of dissolved organic matter and aids in the formation of nutrient-dense foam [28].

Composition

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The composition of sea foam is generally a mixture of decomposed organic materials, including zooplankton, phytoplankton, algae (including diatoms[3] [23]), bacteria, fungi, protozoans, and vascular plant detritus (28), though each occurrence of sea foam varies in its specific contents. In some areas, sea foam is found to be made up of primarily protein, dominant in both fresh and old foam, as well as lipids and carbohydrates. The high protein and low carbohydrate concentration suggest that sugars originally present in the surrounding mucilage created by algae or plant matter has been quickly consumed by bacteria. [29] Additional research has shown that between a small fraction of sea foam measured by dry weight is organic carbon, which contains phenolics, sugars, amino sugars, and amino acids. In the Bay of Fundy, high mortality rates of an abundant tube-dwelling amphipod (Corophium volutator) by natural die-offs as well as predation by migrating seabirds contributed to amino sugars released in the surrounding environment and thus, in sea foam. [28]

The organic matter in sea foam has been found to increase dramatically during phytoplankton blooms in the area. [19] Some research has shown very high concentrations of microplankton in sea foam, with significantly higher numbers of autotrophic phytoplankton than heterotrophs. [23] Some foams are particularly rich in their diatom population which can make up the majority of the microalgal biomass in some cases. [23] A diversity of bacteria is also present in sea foam; old foam tends to have a higher density of bacteria. One study found that 95% of sea foam bacteria was rod-shaped, while the surrounding surface water contained mostly coccoid-form bacteria and only 5% - 10% rod-shaped bacteria. [29] There is also seasonal variability of sea foam composition [28]; in some regions there is a seasonal occurrence of pollen in sea foam which can alter its chemistry. [27] Though foam is not inherently toxic, it may contain high concentrations of contaminants. [21] Foam bubbles can be coated with or contain these materials which can include petroleum compounds, pesticides, and herbicides. [21]

Longevity and stability

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Structurally, sea foam is thermodynamically unstable, though some sea foam can persist in the environment for several days at most. There are two types of sea foam categorized based on their stability: 1) Unstable or transient foams have very short lifetimes of only seconds. The bubbles formed in sea foam may burst releasing aerosols into the air, contributing to sea spray. 2) Metastable foams can have a lifetime of several hours to several days; their duration is sometimes attributed to small particles of silica, calcium, or iron which contribute to foam stability and longevity. [21] Additionally, seawater that contains released dissolved organic material from phytoplankton and macrophytic algae that is then agitated in its environment is most likely to produce stable, longer-lasting foam when compared with seawater lacking one of those components. For example, filtered seawater with added with the fronds of the kelp, Ecklonia maxima, produced foam but it lacked the stability that unfiltered seawater provided. Additionally, kelp fronds that were maintained in flowing water therefore reducing their mucus coating, were unable to help foam form. [29] Different types of salt are also found to have varying effects on bubble proximity within sea foam, therefore contributing to its stability. [21]

Ecological role

[edit]

Food Source

[edit]

The presence of sea foam in the marine environment plays a number of ecological roles including providing sources of food and creating habitat. As a food source, sea foam with a stable composition is more important ecologically, as it is able to persist longer and can transport nutrients within the marine environment. [29] Longer decay times result in a higher chance that energy contained in sea foam will move up the food web into higher trophic levels. [29] In the Bay of Fundy for example, a tube-dwelling amphipod, Corophium volutator, can potentially attain 70% of its nutritional requirements from the sugars and amino acids derived from sea foam in its environment. At times however, the sea foam was found to be toxic to this species. It is thought that high concentrations of phenolics and/or the occasional presence of heavy metals or pesticides incorporated into the sea foam from the sea surface contributed to its toxicity. [28] On the west coast of Cape Peninsula, South Africa, sea foam often occurs in nearshore marine areas with large kelp beds during periods of strong westerly winds. It is thought that the foam generated in these conditions is an important food source for local organisms due to the presence of organic detritus in the sea foam. [29]

Material Transport

[edit]

Sea foam also acts as a mode of transport for both organisms and nutrients within the marine environment and, at times, into the intertidal or terrestrial environments. Wave action can deposit foam into intertidal areas where it can remain when the tide recedes, bringing nutrients to the intertidal zone. [28] Additionally, sea foam can become airborne in windy conditions, transporting materials between marine and terrestrial environments. [27] The ability of sea foam to transport materials is also thought to benefit macroalgal organisms, as macroalgae propagules can be carried to different microenvironments, thus influencing the tidal landscape and contributing to new possible ecological interactions. [20] As sea foam is a wet environment, it is conducive habitat to algal spores where propagules can attach to the substrate and avoid risk of dissemination. [20] When sea foam contains fungi, it can also aid in the decomposition of plant and animal remains in coastal ecosystems. [27]

Habitat

[edit]

Additionally, sea foam is a habitat for a number of marine microorganisms. Some research has shown the presence of various microphytoplanktonic, nanophytoplanktonic, and diatom groups in seafoam; the phytoplankton groups appeared in significantly higher abundance than in sea surface film and the top pelagic zone. [23]

Hazards

[edit]

Toxicity

[edit]

Naturally occurring sea foam is not inherently toxic; however, it can be exposed to high concentrations of contaminants in the surface microlayer derived from the breakdown of algal blooms, fossil fuel production and transport, and stormwater runoff (21). These contaminants contribute to the formation of noxious sea foam through adsorption onto bubbles. Bubbles may burst and release toxins into the atmosphere in the form of sea spray or aerosol, or they may persist in foams. Toxins released through aerosols and breaking bubbles can be inhaled by humans. The microorganisms that occupy sea foams as habitat have increased susceptibility for contaminant exposure (38). Consequently, these toxic substances can be integrated into the trophic food web (21).

Harmful algal blooms

[edit]

Foams can form following the degradation of harmful algal blooms (HABs). These are primarily composed of algal species, but can also consist of dinoflagellates and cyanobacteria (30). Biomass from algae in the bloom is integrated into sea foam in the sea surface microlayer (19). When the impacted sea foam breaks down, toxins from the algae are released into the air causing respiratory issues and occasionally initiating asthma attacks (37). Phaeocystis globosa is one algal species that is considered problematic, as observed in a study in the Netherlands (30). Its high biomass accumulation allows it to create large quantities of toxic foam that often wash onto beaches. P. globosa blooms are initiated in areas of high nutrient availability, often affiliated with coastal locations with a lot of stormwater runoff and eutrophication. Studies suggest that the development of foam is directly correlated to blooms caused by P. globosa, despite that foam formation typically occurs approximately two weeks after the appearance of an algal bloom offshore. Organic material from P. globosa was observed decomposing while suspended at the sea surface, but was not observed lower in the water column. P. globosa is also considered a nuisance species because its large foam formations impair the public’s ability to enjoy the beach (30).

Human activities

[edit]

While sea foam is a common result of the agitation of seawater mixing with organic material in the surface ocean, human activities can contribute to the production of excess and often toxic foam (21). In addition to the organic oils, acids, and proteins that amass in the sea surface microlayer, compounds derived from petroleum production and transport, synthetic surfactants, and pesticide use can enter the sea surface and be incorporated into foam. The pollutants present can also affect the persistence of the foam produced. Crude oil discharged from tankers, motor oil, sewage, and detergents from polluted runoff can create longer-lasting foams (21). In one study, polychlorinated biphenyls (PCBs), a persistent organic pollutant, were found to amass in sea foams (38).

Natural gas terminals have been cited as contributors to the production of modified foams due to the process of using seawater to convert natural gas to liquified natural gas (25). One study showed a much greater abundance of heterotrophic prokaryotes (archaea and bacteria) and cyanobacteria in foam that was generated near a liquified natural gas terminal. These prokaryotes were able to recycle chemical materials discharged from the terminal, which enhanced microbial growth. Additionally, higher levels of total organic carbon (TOC) and plankton biomass were recorded in foam generated in close proximity to the terminal. Organic carbon was transferred readily into the pelagic food web after uptake my prokaryotes and ingestion by grazers (25).

Notable occurrences

[edit]

Sea spray has frequently appeared in the literature and media, some interesteing instances of which include but are not limited to:

References

[edit]
  1. ^ "Eleanor whips up sea foam party for dog". BBC News. Retrieved 2018-01-04.
  2. ^ [1] The Independent, 16 October 2017. Retrieved 18 October 2017.
  3. ^ "Thick sea foam rolls onto Sarina Beach during Cyclone Debbie". abc.net.au. 28 March 2017. Retrieved 11 September 2017.
  4. ^ "East coast low: Sea foam whipped up by storms could be hazardous to health, toxicologist warns". abc.net.au. 7 June 2016. Retrieved 11 September 2017.
  5. ^ "Sunshine Coast Winter Wonderland". Ninemsn. 28 January 2013. Archived from the original on 29 January 2013. Retrieved 28 January 2013.
  6. ^ "Foam swept in as gales hit Scotland". BBC News. 28 September 2012. Retrieved 30 November 2012.
  7. ^ "FOX 5's Tucker Barnes Braves the Sea Foam in Ocean City". Fox 5. Archived from the original on January 16, 2012.
  8. ^ "Sea foam swamps cars at seaside resort of Cleveleys". BBC News. 29 December 2011. Retrieved 30 November 2012.
  9. ^ A. Lander, The foam is back!, Sunshine Coast Daily, 20 February 2008. Accessed 5 November 2010
  10. ^ A. Lander, No place like foam Sunshine Coast Daily, 24 January 2008. Accessed 5 November 2010
  11. ^ Mark Furler, Foam a global hit, Sunshine Coast Daily, 26 January 2008. Accessed 5 November 2010
  12. ^ Samantha Williams, Yamba hit by foam lather, The Daily Telegraph, 27 August 2007. Accessed 5 November 2010
  13. ^ 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
  14. ^ Eric Shackle, Australia Foams at the Mouth, OhmyNews, 26 January 2008. Accessed 5 November 2010
  15. ^ Brett M.Christensen, Whipped Ocean – Beach Foam at Yamba New South Wales, Hoax-Slayer.com, August 2008. Accessed 5 November 2010