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78-455: Spindrift (more rarely spoondrift ) is the spray blown from cresting waves during a gale . This spray, which "drifts" in the direction of the gale, is one of the characteristics of a wind speed of 8 Beaufort and higher at sea. In Greek and Roman mythology, Leucothea was the goddess of spindrift. Spindrift is derived from the Scots language , but its further etymology is uncertain. Although

156-489: A terrestrial gross primary production of 123±8 Gt carbon (NOT carbon dioxide) per year during 1998-2005 In areal terms, it was estimated that land production was approximately 426 g C m yr (excluding areas with permanent ice cover), while that for the oceans was 140 g C m yr . Another significant difference between the land and the oceans lies in their standing stocks - while accounting for almost half of total production, oceanic autotrophs only account for about 0.2% of

234-419: A collapse of the bubble cavity and are ejected from the sea surface in the form of a vertical jet. In windy conditions, water droplets are mechanically torn off from crests of breaking waves. Sea spray droplets generated via such a mechanism are called spume droplets and are typically larger in size and have less residence time in air. Impingement of plunging waves on sea surface also generates sea spray in

312-400: A measure of net photosynthesis (i.e. oxygen production via photosynthesis subtract oxygen consumption by respiration). Gross primary production is then obtained by adding oxygen consumption in the dark vessel to net oxygen production in the light vessel. The technique of using C incorporation (added as labelled Na 2 CO 3 ) to infer primary production is most commonly used today because it

390-490: A new indicator of sustainable development based precisely on the estimation of the human appropriation of NPP: he coined it "HANPP" (Human Appropriation of Net Primary Production) and introduced it at the inaugural conference of the European Society for Ecological Economics. HANPP has since been further developed and widely applied in research on ecological economics and in policy analysis for sustainability. HANPP represents

468-400: A number of comprehensive reviews of the field methods used to estimate NPP. Estimates of ecosystem respiration , the total carbon dioxide produced by the ecosystem, can also be made with gas flux measurements . The major unaccounted pool is belowground productivity, especially production and turnover of roots. Belowground components of NPP are difficult to measure. BNPP (below-ground NPP)

546-506: A proxy of the human impact on nature and can be applied to different geographical and global scales. The extensive degree of human use of the Planet's resources, mostly via land use , results in various levels of impact on actual NPP (NPP act ). Although in some regions, such as the Nile valley, irrigation has resulted in a considerable increase in primary production, in most of the Planet, there

624-473: Is sunlight but a minute fraction of primary production is driven by lithotrophic organisms using the chemical energy of inorganic molecules. Regardless of its source, this energy is used to synthesize complex organic molecules from simpler inorganic compounds such as carbon dioxide (CO 2 ) and water (H 2 O). The following two equations are simplified representations of photosynthesis (top) and (one form of) chemosynthesis (bottom): In both cases,

702-406: Is "consumed" in plants by the processes of photosynthesis (see above) and transpiration . The latter process (which is responsible for about 90% of water use) is driven by the evaporation of water from the leaves of plants. Transpiration allows plants to transport water and mineral nutrients from the soil to growth regions, and also cools the plant. Diffusion of water vapour out of a leaf,

780-431: 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. Primary production In ecology , primary production

858-448: Is a notable trend of NPP reduction due to land changes (ΔNPP LC ) of 9.6% across global land-mass. In addition to this, end consumption by people raises the total HANPP to 23.8% of potential vegetation (NPP 0 ). It is estimated that, in 2000, 34% of the Earth's ice-free land area (12% cropland ; 22% pasture ) was devoted to human agriculture. This disproportionate amount reduces

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936-867: Is almost always the desired variable, and estimation techniques involve various methods of estimating dry-weight biomass changes over time. Biomass estimates are often converted to an energy measure, such as kilocalories, by an empirically determined conversion factor. In terrestrial ecosystems, researchers generally measure net primary production (NPP). Although its definition is straightforward, field measurements used to estimate productivity vary according to investigator and biome. Field estimates rarely account for below ground productivity, herbivory, turnover, litterfall , volatile organic compounds , root exudates, and allocation to symbiotic microorganisms. Biomass based NPP estimates result in underestimation of NPP due to incomplete accounting of these components. However, many field measurements correlate well to NPP. There are

1014-540: Is also used to refer to fine sand or snow that is blown off the ground by the wind. Sea spray Sea spray is directly (and indirectly, through SSA) responsible for a significant degree of the heat and moisture fluxes between the atmosphere and the ocean, affecting global climate patterns and tropical storm intensity. Sea spray also influences plant growth and species distribution in coastal ecosystems and increases corrosion of building materials in coastal areas. When wind, whitecaps, and breaking waves mix air into

1092-681: Is assumed to measure NPP. In systems with persistent standing litter, live biomass is commonly reported. Measures of peak biomass are more reliable if the system is predominantly annuals. However, perennial measurements could be reliable if there were a synchronous phenology driven by a strong seasonal climate. These methods may underestimate ANPP in grasslands by as much as 2 ( temperate ) to 4 ( tropical ) fold. Repeated measures of standing live and dead biomass provide more accurate estimates of all grasslands, particularly those with large turnover, rapid decomposition, and interspecific variation in timing of peak biomass. Wetland productivity (marshes and fens)

1170-633: Is attested later than spindrift and it seems unlikely that the Scots spelling would have superseded the English one, and because the early use of the word in the form spenedrift by James Melville (1556–1614) is unlikely to have derived from spoondrift . In any case, spindrift was popularized in England through its use in the novels of the Scottish-born author William Black (1841–1898). Spindrift or spoondrift

1248-414: Is done by performing a Winkler titration . The other two vessels are incubated, one each in under light and darkened. After a fixed period of time, the experiment ends, and the oxygen concentration in both vessels is measured. As photosynthesis has not taken place in the dark vessel, it provides a measure of ecosystem respiration . The light vessel permits both photosynthesis and respiration, so provides

1326-491: Is exacerbated where summertime solar heating and reduced winds increases vertical stratification and leads to a strong thermocline , since this makes it more difficult for wind mixing to entrain deeper water. Consequently, between mixing events, primary production (and the resulting processes that leads to sinking particulate material) constantly acts to consume nutrients in the mixed layer, and in many regions this leads to nutrient exhaustion and decreased mixed layer production in

1404-423: Is logistically difficult to measure. Shallow water aquatic systems can also face this problem. Scale also greatly affects measurement techniques. The rate of carbon assimilation in plant tissues, organs, whole plants, or plankton samples can be quantified by biochemically based techniques , but these techniques are decidedly inappropriate for large scale terrestrial field situations. There, net primary production

1482-499: Is most often used as the unit of measurement. Note that a distinction is sometimes drawn between "production" and "productivity", with the former the quantity of material produced (g C m ), the latter the rate at which it is produced (g C m yr ), but these terms are more typically used interchangeably. On the land, almost all primary production is now performed by vascular plants , with a small fraction coming from algae and non-vascular plants such as mosses and liverworts . Before

1560-409: Is not an issue (though its salinity can be). Similarly, temperature, while affecting metabolic rates (see Q 10 ), ranges less widely in the ocean than on land because the heat capacity of seawater buffers temperature changes, and the formation of sea ice insulates it at lower temperatures. However, the availability of light, the source of energy for photosynthesis, and mineral nutrients ,

1638-404: Is observed that there is some reduction in the air/sea momentum flux. This reduction in momentum flux manifests as saturation of air/sea drag coefficient . Some studies have identified spray effects as one of the potential reasons for the air/sea drag coefficient saturation. It has been shown through several numerical and theoretical studies that sea spray, if present in significant amounts in

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1716-470: Is often estimated based on a ratio of ANPP:BNPP (above-ground NPP:below-ground NPP) rather than direct measurements. Gross primary production can be estimated from measurements of net ecosystem exchange (NEE) of carbon dioxide made by the eddy covariance technique . During night, this technique measures all components of ecosystem respiration. This respiration is scaled to day-time values and further subtracted from NEE. Most frequently, peak standing biomass

1794-531: Is performed by algae, with a small fraction contributed by vascular plants and other groups. Algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds . They include photoautotrophs from a variety of groups. Eubacteria are important photosynthetizers in both oceanic and terrestrial ecosystems, and while some archaea are phototrophic , none are known to utilise oxygen-evolving photosynthesis. A number of eukaryotes are significant contributors to primary production in

1872-434: 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 . At high winds the droplet evaporation layer (DEL) influences the surface energy heat exchange of

1950-525: Is referred to as net primary production (NPP). Net primary production is the rate at which all the autotrophs in an ecosystem produce net useful chemical energy. Net primary production is available to be directed toward growth and reproduction of primary producers. As such it is available for consumption by herbivores. Both gross and net primary production are typically expressed in units of mass per unit area per unit time interval. In terrestrial ecosystems, mass of carbon per unit area per year (g C m yr )

2028-760: Is reflected in the composition of sea spray. Generally speaking, sea spray has slightly lower concentrations of microbes than the water it is produced from. However, the microbial community in sea spray is often distinct from nearby water and sandy beaches, suggesting that some species are more biased towards SSA transportation than others. Sea spray from one beach can contain thousands of operational taxonomic units (OTUs). Nearly 10,000 different OTUs have been discovered in sea spray just between San Francisco, CA and Monterey, CA, with only 11% of them found ubiquitously. This suggests that sea spray in every coastal region likely has its own unique assemblage of microbial diversity, with thousands of new OTUs yet to be discovered. Many of

2106-433: Is sensitive, and can be used in all ocean environments. As C is radioactive (via beta decay ), it is relatively straightforward to measure its incorporation in organic material using devices such as scintillation counters . Depending upon the incubation time chosen, net or gross primary production can be estimated. Gross primary production is best estimated using relatively short incubation times (1 hour or less), since

2184-436: Is shallower than the critical depth. Both the magnitude of wind mixing and the availability of light at the ocean's surface are affected across a range of space- and time-scales. The most characteristic of these is the seasonal cycle (caused by the consequences of the Earth's axial tilt ), although wind magnitudes additionally have strong spatial components . Consequently, primary production in temperate regions such as

2262-553: Is similarly measured. In Europe , annual mowing makes the annual biomass increment of wetlands evident. Methods used to measure forest productivity are more diverse than those of grasslands. Biomass increment based on stand specific allometry plus litterfall is considered a suitable although incomplete accounting of above-ground net primary production (ANPP). Field measurements used as a proxy for ANPP include annual litterfall, diameter or basal area increment ( DBH or BAI), and volume increment. In aquatic systems, primary production

2340-522: Is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide . It principally occurs through the process of photosynthesis , which uses light as its source of energy, but it also occurs through chemosynthesis , which uses the oxidation or reduction of inorganic chemical compounds as its source of energy. Almost all life on Earth relies directly or indirectly on primary production. The organisms responsible for primary production are known as primary producers or autotrophs , and form

2418-422: Is typically measured using one of six main techniques: The technique developed by Gaarder and Gran uses variations in the concentration of oxygen under different experimental conditions to infer gross primary production. Typically, three identical transparent vessels are filled with sample water and stoppered . The first is analysed immediately and used to determine the initial oxygen concentration; usually this

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2496-505: Is using the triple oxygen isotopes of sulfate . Together these records suggest large shifts in primary production throughout Earth's past with notable rises associated with Earth's Great Oxidation Event (approximately 2.4 to 2.0 billion years ago) and the Neoproterozoic (approximately 1.0 to 0.54 billion years ago). Human societies are part of the Earth's NPP cycle but disproportionately influence it. In 1996, Josep Garí designed

2574-567: The Oxford English Dictionary suggests it is a variant of spoondrift based on the way that word was pronounced in southwest Scotland, from spoon or spoom ("to sail briskly with the wind astern, with or without sails hoisted") and drift ("a mass of matter driven or forced onward together in a body, etc., especially by wind or water"), this is doubted by the Scottish National Dictionary , because spoondrift

2652-476: The North Atlantic is highly seasonal, varying with both incident light at the water's surface (reduced in winter) and the degree of mixing (increased in winter). In tropical regions, such as the gyres in the middle of the major basins , light may only vary slightly across the year, and mixing may only occur episodically, such as during large storms or hurricanes . Mixing also plays an important role in

2730-624: The biosphere is an important part of the carbon cycle , estimating it at the global scale is important in Earth system science . However, quantifying primary production at this scale is difficult because of the range of habitats on Earth, and because of the impact of weather events (availability of sunlight, water) on its variability. Using satellite -derived estimates of the Normalized Difference Vegetation Index (NDVI) for terrestrial habitats and sea-surface chlorophyll for

2808-590: The evolution of vascular plants, non-vascular plants likely played a more significant role. Primary production on land is a function of many factors, but principally local hydrology and temperature (the latter covaries to an extent with light, specifically photosynthetically active radiation (PAR), the source of energy for photosynthesis). While plants cover much of the Earth's surface, they are strongly curtailed wherever temperatures are too extreme or where necessary plant resources (principally water and PAR) are limiting, such as deserts or polar regions . Water

2886-415: The littoral zone and adjacent shallow waters, where they can attach to the underlying substrate but still be within the photic zone . There are exceptions, such as Sargassum , but the vast majority of free-floating production takes place within microscopic organisms. The factors limiting primary production in the ocean are also very different from those on land. The availability of water, obviously,

2964-445: The advantage of providing estimates of respiration rates in the light without the need of incubations in the dark. Among them, the method of the triple oxygen isotopes and O 2 /Ar have the additional advantage of not needing incubations in closed containers and O 2 /Ar can even be measured continuously at sea using equilibrator inlet mass spectrometry (EIMS) or a membrane inlet mass spectrometry (MIMS). However, if results relevant to

3042-421: 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. The effects of sea spray transport in the atmospheric boundary layer is not yet completely understood. Sea spray droplets alter the air-sea momentum fluxes by being accelerated and decelerated by the winds. In hurricane-force winds, it

3120-512: The animation, the boreal forests of Canada and Russia experience high productivity in June and July and then a slow decline through fall and winter. Year-round, tropical forests in South America, Africa, Southeast Asia, and Indonesia have high productivity, not surprising with the abundant sunlight, warmth, and rainfall. However, even in the tropics, there are variations in productivity over the course of

3198-430: The atmospheric boundary layer, leads to saturation of air-sea drag coefficients. 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

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3276-450: The base of the food chain . In terrestrial ecoregions , these are mainly plants , while in aquatic ecoregions algae predominate in this role. Ecologists distinguish primary production as either net or gross , the former accounting for losses to processes such as cellular respiration , the latter not. Primary production is the production of chemical energy in organic compounds by living organisms . The main source of this energy

3354-424: The building blocks for new growth, play crucial roles in regulating primary production in the ocean. Available Earth System Models suggest that ongoing ocean bio-geochemical changes could trigger reductions in ocean NPP between 3% and 10% of current values depending on the emissions scenario. The sunlit zone of the ocean is called the photic zone (or euphotic zone). This is a relatively thin layer (10–100 m) near

3432-403: The carbon cycle are desired, it is probably better to rely on methods based on carbon (and not oxygen) isotopes. It is important to notice that the method based on carbon stable isotopes is not simply an adaptation of the classic C method, but an entirely different approach that does not suffer from the problem of lack of account of carbon recycling during photosynthesis. As primary production in

3510-428: The contribution of sea spray DMS to the atmosphere is linked to the global sulfur cycle . 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. The proportion of organic matter in sea spray can impact reflectance , determine

3588-473: The end point is a polymer of reduced carbohydrate , (CH 2 O) n , typically molecules such as glucose or other sugars . These relatively simple molecules may be then used to further synthesise more complicated molecules, including proteins , complex carbohydrates , lipids , and nucleic acids , or be respired to perform work . Consumption of primary producers by heterotrophic organisms, such as animals , then transfers these organic molecules (and

3666-492: The energy available to other species, having a marked impact on biodiversity , flows of carbon, water, and energy, and ecosystem services , . Scientists have questioned how large this fraction can be before these services break down. Reductions in NPP are also expected in the ocean as a result of ongoing climate change, potentially impacting marine ecosystems (~10% of global biodiversity) and goods and services (1-5% of global total) that

3744-510: The energy stored within them) up the food web , fueling all of the Earth 's living systems. Gross primary production (GPP) is the amount of chemical energy, typically expressed as carbon biomass , that primary producers create in a given length of time. Some fraction of this fixed energy is used by primary producers for cellular respiration and maintenance of existing tissues (i.e., "growth respiration" and " maintenance respiration "). The remaining fixed energy (i.e., mass of photosynthate)

3822-420: The experimental species used. Aside from those caused by the physiology of the experimental subject itself, potential losses due to the activity of consumers also need to be considered. This is particularly true in experiments making use of natural assemblages of microscopic autotrophs, where it is not possible to isolate them from their consumers. The methods based on stable isotopes and O 2 /Ar ratios have

3900-420: The focus. Gross production is almost always harder to measure than net, because of respiration, which is a continuous and ongoing process that consumes some of the products of primary production (i.e. sugars) before they can be accurately measured. Also, terrestrial ecosystems are generally more difficult because a substantial proportion of total productivity is shunted to below-ground organs and tissues, where it

3978-657: The force that drives transpiration, is regulated by structures known as stomata . These structures also regulate the diffusion of carbon dioxide from the atmosphere into the leaf, such that decreasing water loss (by partially closing stomata) also decreases carbon dioxide gain. Certain plants use alternative forms of photosynthesis, called Crassulacean acid metabolism (CAM) and C4 . These employ physiological and anatomical adaptations to increase water-use efficiency and allow increased primary production to take place under conditions that would normally limit carbon fixation by C3 plants (the majority of plant species). As shown in

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4056-477: The form of splash droplets . 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

4134-437: The limitation of primary production by nutrients. Inorganic nutrients, such as nitrate , phosphate and silicic acid are necessary for phytoplankton to synthesise their cells and cellular machinery. Because of gravitational sinking of particulate material (such as plankton , dead or fecal material), nutrients are constantly lost from the photic zone, and are only replenished by mixing or upwelling of deeper water. This

4212-409: The loss of incorporated C (by respiration and organic material excretion / exudation) will be more limited. Net primary production is the fraction of gross production remaining after these loss processes have consumed some of the fixed carbon. Loss processes can range between 10 and 60% of incorporated C according to the incubation period, ambient environmental conditions (especially temperature) and

4290-570: 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. 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

4368-428: The mixing state. A lesser studied area of sea spray generation is the formation of sea spray as a result of rain drop impact on the sea surface . In addition to the local conditions that influence sea spray formation, there are also consistent spatial patterns in sea spray production and composition. Because sea spray is generated when air is mixed into the ocean, formation gradients are established by turbulence of

4446-485: The more common OTUs have been identified to the following taxa: Cryptophyta (order), Stramenopiles (order) and OM60 (family). Many have even been identified to genus: Persicirhabdus, Fluviicola, Synecococcus, Vibrio, and Enterococcus. Scientists have conjectured a stream of airborne microorganisms circles the planet above weather systems but below commercial air lanes. Some of these peripatetic microorganisms are swept up from terrestrial dust storms, but most originate from

4524-1041: The ocean but increases with increasing wind speed. Salt deposition from sea spray is correlated with a decrease in plant height and significant scarring, shoot reduction, stem height decrease, and tissue death on the windward side of shrubs and trees. Variation in salt deposition also influences competition between plants and establishes gradients of salt tolerance. While the salts within sea spray can severely inhibit plant growth in coastal ecosystems, selecting for salt-tolerant species, sea spray can also bring vital nutrients to these habitats. For example, one study showed that sea spray in Wales, UK delivers roughly 32 kg of potassium per hectare to coastal sand dunes each year. Because dune soils leach nutrients very quickly, sea spray fertilization could be very influential to dune ecosystems, especially for plants that are less competitive in nutrient-limited environments. Viruses, bacteria, and plankton are ubiquitous in sea water, and this biodiversity

4602-445: The ocean surface turbulent enough to produce significant sea spray is called the whitecap fraction. The only other production mechanism of sea spray in the open ocean is through direct wind action, where strong winds actually break the surface tension of the water and lift particles into the air. However, particles of seawater generated in this way are often too heavy to remain suspended in the atmosphere and usually are deposited back to

4680-424: The ocean's surface where there is sufficient light for photosynthesis to occur. For practical purposes, the thickness of the photic zone is typically defined by the depth at which light reaches 1% of its surface value. Light is attenuated down the water column by its absorption or scattering by the water itself, and by dissolved or particulate material within it (including phytoplankton). Net photosynthesis in

4758-449: The ocean, including green algae , brown algae and red algae , and a diverse group of unicellular groups. Vascular plants are also represented in the ocean by groups such as the seagrasses . Unlike terrestrial ecosystems, the majority of primary production in the ocean is performed by free-living microscopic organisms called phytoplankton . Larger autotrophs, such as the seagrasses and macroalgae ( seaweeds ) are generally confined to

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4836-481: 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

4914-490: The oceans is dust from the Earth's deserts , picked up and delivered by the wind as aeolian dust . In regions of the ocean that are distant from deserts or that are not reached by dust-carrying winds (for example, the Southern and North Pacific oceans), the lack of iron can severely limit the amount of primary production that can occur. These areas are sometimes known as HNLC (High-Nutrient, Low-Chlorophyll) regions, because

4992-612: The oceans, it is estimated that the total (photoautotrophic) primary production for the Earth was 104.9 petagrams of carbon per year (Pg C yr ; equivalent to the non- SI Gt C yr ). Of this, 56.4 Pg C yr (53.8%), was the product of terrestrial organisms, while the remaining 48.5 Pg C yr , was accounted for by oceanic production. Scaling ecosystem-level GPP estimations based on eddy covariance measurements of net ecosystem exchange (see above) to regional and global values using spatial details of different predictor variables, such as climate variables and remotely sensed fAPAR or LAI led to

5070-457: The overall cooling effect of SSAs, and slightly alter the capacity for SSAs to form cloud condensation nuclei (17). Even small changes in SSA levels can affect the global radiation budget leading to implications for global climate. SSA has a low albedo , but its presence overlaid on the darker ocean surface affects absorption and reflectance of incoming solar radiation. The influence of sea spray on

5148-402: The photic zone, to being much deeper than the photic zone. When it is much deeper than the photic zone, this results in phytoplankton spending too much time in the dark for net growth to occur. The maximum depth of the mixed layer in which net growth can occur is called the critical depth . As long as there are adequate nutrients available, net primary production occurs whenever the mixed layer

5226-594: The properties of the water from which it was produced, the composition of sea spray experiences extreme seasonal variation. During the summer, dissolved organic carbon (DOC) can constitute 60-90% of sea spray mass. Even though much more sea spray is produced during the stormy winter season, the composition is nearly all salt because of the low primary production. The organic matter in sea spray consists of dissolved organic carbon (DOC) and even microbes themselves, like bacteria and viruses. The amount of organic matter in sea spray depends on microbiological processes, though

5304-432: The scarcity of iron both limits phytoplankton growth and leaves a surplus of other nutrients. Some scientists have suggested introducing iron to these areas as a means of increasing primary productivity and sequestering carbon dioxide from the atmosphere. The methods for measurement of primary production vary depending on whether gross vs net production is the desired measure, and whether terrestrial or aquatic systems are

5382-425: 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. Film droplets make up the majority of the smaller particles created by the initial burst, while jet droplets are generated by

5460-422: 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. Additionally,

5538-445: The sea within a few dozen meters of transport. During winter months, the ocean typically experiences stormy, windy conditions that generate more air inundation into the sea and therefore more sea spray. Calmer summer months result in lower overall production of sea spray. During peak primary productivity in the summer, increased organic matter in the surface ocean drives subsequent increases in sea spray. Given that sea spray retains

5616-520: The summer (even in the presence of abundant light). However, as long as the photic zone is deep enough, primary production may continue below the mixed layer where light-limited growth rates mean that nutrients are often more abundant. Another factor relatively recently discovered to play a significant role in oceanic primary production is the micronutrient iron . This is used as a cofactor in enzymes involved in processes such as nitrate reduction and nitrogen fixation . A major source of iron to

5694-445: The surface heat and moisture exchange peaks during times of greatest difference between air and sea temperatures. When air temperature is low, sea spray sensible heat flux can be nearly as great as the spray latent heat flux at high latitudes. In addition, sea spray enhances the air/sea enthalpy flux during high winds as a result of temperature and humidity redistribution in the marine boundary layer . Sea spray droplets injected into

5772-413: The surface water. Wave action along coastal shorelines is generally where turbulence is greatest, so this is where sea spray production is the highest. Particles generated in turbulent coastal areas can travel horizontally up to 25 km within the planetary boundary layer . As distance from shore decreases, sea spray production declines to a level sustained almost exclusively by whitecaps. The proportion of

5850-425: The total biomass. Present day primary productivity can be estimated through a variety of methodologies including ship-board measurements, satellites and terrestrial observatories. Historical estimates have relied on biogeochemical models and geochemical proxies. One example is using barium , where barite concentrations in marine sediments rise in line with carbon export production at the surface. Another example

5928-432: 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

6006-432: The water column is determined by the interaction between the photic zone and the mixed layer . Turbulent mixing by wind energy at the ocean's surface homogenises the water column vertically until the turbulence dissipates (creating the aforementioned mixed layer). The deeper the mixed layer, the lower the average amount of light intercepted by phytoplankton within it. The mixed layer can vary from being shallower than

6084-476: The year. For example, the Amazon basin exhibits especially high productivity from roughly August through October - the period of the area's dry season. Because the trees have access to a plentiful supply of ground water that builds up in the rainy season, they grow better when the rainy skies clear and allow more sunlight to reach the forest. In a reversal of the pattern on land, in the oceans, almost all photosynthesis

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