Ocean foam
Encyclopedia
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 protein
s, lignin
s, and lipid
s) derived from sources such as the offshore breakdown of algal bloom
s. These compounds can act as surfactant
s or foaming agent
s. As the seawater is churned by breaking wave
s 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 beach
face inland onto sidewalks and streets.
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.
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 detergent
s 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 dinoflagellate
s 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.
, 29°26′S 153°21′W on 24 August 2007, and attracted world-wide media attention.
Other sea foam occurrences at Caloundra 26°48′S 153°08′E and Point Cartwright
, 26°40′47.8"S 153°08′18.1"E, 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.
Foam
-Definition:A foam is a substance that is formed by trapping gas in a liquid or solid in a divided form, i.e. by forming gas regions inside liquid regions, leading to different kinds of dispersed media...
created by the agitation of seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
, particularly when it contains higher concentrations of dissolved organic matter (including protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s, lignin
Lignin
Lignin or lignen is a complex chemical compound most commonly derived from wood, and an integral part of the secondary cell walls of plants and some algae. The term was introduced in 1819 by de Candolle and is derived from the Latin word lignum, meaning wood...
s, and lipid
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
s) derived from sources such as the offshore breakdown of algal bloom
Algal bloom
An algal bloom is a rapid increase or accumulation in the population of algae in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration...
s. These compounds can act as surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
s or foaming agent
Foaming agent
A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....
s. As the seawater is churned by breaking wave
Breaking wave
In fluid dynamics, a breaking wave is a wave whose amplitude reaches a critical level at which some process can suddenly start to occur that causes large amounts of wave energy to be transformed into turbulent kinetic energy...
s in the surf zone adjacent to the shore, the presence of these surfactants under these turbulent conditions traps air, forming persistent bubbles
Liquid bubble
A bubble is a globule of one substance in another, usually gas in a liquid.Due to the Marangoni effect, bubbles may remain intact when they reach the surface of the immersive substance.-Common examples:...
which stick to each other through surface tension
Surface tension
Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects to run on the water surface...
. Due to its low density and persistence, foam can be blown by strong on-shore winds from the beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
face inland onto sidewalks and streets.
Hazards
Where polluted stormwater
Stormwater
Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...
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
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
discharged from tankers at sea, or motor oil
Motor oil
Motor oil or engine oil is an oil used for lubrication of various internal combustion engines. The main function is to lubricate moving parts; it also cleans, inhibits corrosion, improves sealing, and cools the engine by carrying heat away from moving parts.Motor oils are derived from...
, sewage
Sewage
Sewage is water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as wastewater, it is more than 99% water and is characterized by volume or rate of flow, physical condition, chemical constituents and the bacteriological organisms that it contains...
and detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...
s from polluted stormwater are present, the resulting sea foam is even more persistent, and can have a chocolate mousse
Mousse
Mousse is derived from the French word mousse which means "lather" or "foam". A mousse is a prepared food that incorporates air bubbles to give it a light and airy texture...
texture.
If the foam forms from the breakdown of a harmful algal bloom (including those caused by some dinoflagellate
Dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...
s 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.
Notable occurrences
A large buildup of sea foam occurred on the coast of Yamba, northern New South WalesYamba, New South Wales
Yamba is a town in northern New South Wales, Australia at the mouth of the Clarence River. The first European to visit the area was Matthew Flinders, who stopped by in Yamba Bay for six days in July 1799....
, 29°26′S 153°21′W on 24 August 2007, and attracted world-wide media attention.
Other sea foam occurrences at Caloundra 26°48′S 153°08′E and Point Cartwright
Mooloolaba, Queensland
Mooloolaba is a suburb and tourist resort township on the Sunshine Coast in Queensland, Australia. It is located north of the state capital, Brisbane, and is part of the Maroochydore urban centre.- Etymology :...
, 26°40′47.8"S 153°08′18.1"E, on Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
's Sunshine Coast
Sunshine Coast, Queensland
The Sunshine Coast is an urban area in South East Queensland, north of the state capital of Brisbane on the Pacific Ocean coastline. Although it does not have a central business district, by population it ranks as the 10th largest metropolis in Australia and the third largest in...
in January–February 2008, also attracted world-wide media attention.
During live coverage of Hurricane Irene in Ocean City, Maryland
Ocean City, Maryland
Ocean City, sometimes known as OC, or OCMD, is an Atlantic Ocean resort town in Worcester County, Maryland, United States. Ocean City is widely known in the Mid-Atlantic region of the United States and is a frequent destination for vacationers in that area...
, Tucker Barnes was covered in sea foam.
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