Sea spray

Formation and sea spray formation. The dark orange line indicates processes common to the formation of both sea spray and sea foam. When wind, whitecaps, and breaking waves mix air into the sea surface, the air regroups to form bubbles, floats to the surface, and bursts at the air-sea interface. When they burst, they release up to a thousand particles of sea spray, which range in size from nanometers to micrometers and can be expelled up to 20 cm from the sea surface.''. The composition of the sea spray depends primarily on the composition of the water from which it is produced, but broadly speaking is a mixture of salts and organic matter. Several factors determine the production flux of sea spray, especially wind speed, swell height, swell period, humidity, and temperature differential between the atmosphere and the surface water. Production and size distribution rate of SSAs are thus sensitive to the mixing state. Calmer summer months result in lower overall production of sea spray. (DOC) and even microbes themselves, like bacteria and viruses. The amount of organic matter in sea spray depends on microbiological processes, though the total effect of these processes is still unknown. Chlorophyll-a is often used as a proxy for primary production and organic matter content in sea spray, but its reliability for estimating dissolved organic carbon concentrations is controversial. Biomass often enters sea spray through the death and lysis of algal cells, often caused by viral infections. Cells are broken apart into the dissolved organic carbon that is propelled into the atmosphere when surface bubbles pop. When primary productivity peaks during the summer, algal blooms can generate an enormous amount of organic matter that is eventually incorporated into sea spray. In the right conditions, aggregation of the dissolved organic carbon can also form surfactant or sea foam. == Climate interactions ==

At high winds the droplet evaporation layer (DEL) influences the surface energy heat exchange of the ocean. The latent heat flux of sea spray generated at the droplet evaporation layer has been cited as an important addition to climate modeling efforts, particularly in simulations assessing air/sea heat balance as related to hurricanes and cyclones formed during high wind events. During the formation of whitecaps, sea spray droplets exhibit the same properties as the ocean surface, but rapidly adapt to surrounding air. Some sea spray droplets immediately reabsorb into the sea while others evaporate entirely and contribute salt particles like dimethyl sulfide (DMS) to the atmosphere where they can be transported via turbulence to cloud layers and serve as cloud condensation nuclei. The formation of these cloud condensation nuclei like dimethyl sulfide have climate implications as well, due to their influence on cloud formation and interaction with solar radiation. Understanding total forcing from natural sources like sea spray can illuminate critical constraints posed by anthropogenic influence and can be coupled with ocean chemistry, biology and physics to predict future ocean and atmospheric variability. Sea spray droplets injected into the air thermally equilibrate ~1% of their mass. This leads to the addition of sensible heat prior to ocean reentry, enhancing their potential for significant enthalpy input. It has been shown through several numerical and theoretical studies that sea spray, if present in significant amounts in the atmospheric boundary layer, leads to saturation of air-sea drag coefficients. == Ecology ==

Coastal ecosystems Salt deposition from sea spray is the primary factor influencing distribution of plant communities in coastal ecosystems. Ion concentrations of sea spray deposited on land generally mirror their concentrations in the ocean, except that potassium is often higher in sea spray. Deposition of salts on land generally decreases with distance from the ocean but increases with increasing wind speed. Variation in salt deposition also influences competition between plants and establishes gradients of salt tolerance. Some of these peripatetic microorganisms are swept up from terrestrial dust storms, but most originate from the marine microorganisms in sea spray. In 2018 a team of scientists reported that hundreds of millions of viruses and tens of millions of bacteria are deposited daily on every square meter around the planet. == Chemical resistance ==

Sea spray is largely responsible for corrosion of metallic objects near the coastline, as the salts accelerate the corrosion process in the presence of abundant atmospheric oxygen and moisture. Salts do not dissolve in air directly, but are suspended as fine particulates, or dissolved in microscopic airborne water droplets. The salt spray test is a measure of material endurance or resistance to corrosion, particularly if the material will be used outdoors and must perform in a mechanical load bearing or otherwise critical role. These results are often of great interest to marine industries, whose products may suffer extreme acceleration of corrosion and subsequent failure due to salt water exposure. ==See also==