Artificial seawater

Last updated

Artificial seawater (abbreviated ASW) is a mixture of dissolved mineral salts (and sometimes vitamins) that simulates seawater. Artificial seawater is primarily used in marine biology and in marine and reef aquaria, and allows the easy preparation of media appropriate for marine organisms (including algae, bacteria, plants and animals). From a scientific perspective, artificial seawater has the advantage of reproducibility over natural seawater since it is a standardized formula. Artificial seawater is also known as synthetic seawater and substitute ocean water.

Contents

Example

The tables below present an example of an artificial seawater (35.00 of salinity) preparation devised by Kester, Duedall, Connors and Pytkowicz (1967). [1] The recipe consists of two lists of mineral salts, the first of anhydrous salts that can be weighed out, the second of hydrous salts that should be added to the artificial seawater as a solution.

Gravimetric salts
SaltMolecular weight g kg−1 solution
Sodium chloride (NaCl)58.4423.926
Sodium sulfate (Na2SO4)142.044.008
Potassium chloride (KCl)74.560.677
Sodium bicarbonate (NaHCO3)84.000.196
Potassium bromide (KBr)119.010.098
Boric acid (H3BO3)61.830.026
Sodium fluoride (NaF)41.990.003
Volumetric salts
SaltMolecular weight mol kg−1 solution
Magnesium chloride (MgCl2.6H2O)203.330.05327
Calcium chloride (CaCl2.2H2O)147.030.01033
Strontium chloride (SrCl2.6H2O)266.640.00009

While all of the compounds listed in the recipe above are inorganic, mineral salts, some artificial seawater recipes, such as Goldman and McCarthy (1978), [2] make use of trace solutions of vitamins or organic compounds.

Standard

The International Standard for making artificial seawater can be found at ASTM International. [3] The current standard is named ASTM D1141-98 [4] (The original standard was ASTM D1141-52) and describes the standard practice for the preparation of substitute ocean water. The ASTM D1141-98 standard comes in a ready-made artificial seawater form or a "Sea Salt" mix that can be prepared by engineers and hobbyists. Generally, the ready-made artificial seawater comes in 1 gallon and 5 gallon containers, whereas the "Sea Salt" mix comes in 20lb pails (makes approximately 57 gallons) and 50lb pails (makes approximately 143 gallons).

Uses and applications

There are various applications for ASTM D1141-98 synthetic seawater including corrosion studies, ocean instrument calibration and chemical processing. [5] Typically, laboratory-grade water is used when making synthetic salts [6]

See also

Related Research Articles

<span class="mw-page-title-main">Acantharea</span> Class of single-celled organisms

The Acantharea (Acantharia) are a group of radiolarian protozoa, distinguished mainly by their strontium sulfate skeletons. Acantharians are heterotrophic marine microplankton that range in size from about 200 microns in diameter up to several millimeters. Some acantharians have photosynthetic endosymbionts and hence are considered mixotrophs.

<span class="mw-page-title-main">Salinity</span> Proportion of salt dissolved in water

Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. It is usually measured in g/L or g/kg.

<span class="mw-page-title-main">Biological pump</span> Carbon capture process in oceans

The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments. In other words, it is a biologically mediated process which results in the sequestering of carbon in the deep ocean away from the atmosphere and the land. The biological pump is the biological component of the "marine carbon pump" which contains both a physical and biological component. It is the part of the broader oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump).

<span class="mw-page-title-main">Magnesium sulfate</span> Chemical compound with formula MgSO4

Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula MgSO4, consisting of magnesium cations Mg2+ (20.19% by mass) and sulfate anions SO2−4. It is a white crystalline solid, soluble in water but not in ethanol.

<span class="mw-page-title-main">Seawater</span> Water from a sea or an ocean

Seawater, or sea water, 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 35 grams (1.2 oz) of dissolved salts. The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier: the measured temperature was −2.6 °C (27.3 °F).

<span class="mw-page-title-main">Magnesium chloride</span> Inorganic salt: MgCl2 and its hydrates

Magnesium chloride is an inorganic compound with the formula MgCl2. It forms hydrates MgCl2·nH2O, where n can range from 1 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.

<span class="mw-page-title-main">Purified water</span> Water treated to remove all impurities

Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently purified by other processes including capacitive deionization, reverse osmosis, carbon filtering, microfiltration, ultrafiltration, ultraviolet oxidation, or electrodeionization. Combinations of a number of these processes have come into use to produce ultrapure water of such high purity that its trace contaminants are measured in parts per billion (ppb) or parts per trillion (ppt).

A bromide ion is the negatively charged form (Br) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant materials, and cell stains. Although uncommon, chronic toxicity from bromide can result in bromism, a syndrome with multiple neurological symptoms. Bromide toxicity can also cause a type of skin eruption, see potassium bromide. The bromide ion has an ionic radius of 196 pm.

<span class="mw-page-title-main">Carbonate rock</span> Class of sedimentary rock

Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolostone), which is composed of mineral dolomite (CaMg(CO3)2). They are usually classified based on texture and grain size. Importantly, carbonate rocks can exist as metamorphic and igneous rocks, too. When recrystallized carbonate rocks are metamorphosed, marble is created. Rare igneous carbonate rocks even exist as intrusive carbonatites and, even rarer, there exists volcanic carbonate lava.

The (oceanic) water column is a concept used in oceanography to describe the physical and chemical characteristics of seawater at different depths for a defined geographical point. Generally, vertical profiles are made of temperature, salinity, chemical parameters at a defined point along the water column. The water column is the largest, yet one of the most under-explored, habitats on the planet; it is explored to better understand the ocean as a whole, including the huge biomass that lives there and its importance to the global carbon and other biogeochemical cycles. Studying the water column also provides understanding on the links between living organisms and environmental parameters, large-scale water circulation and the transfer of matter between water masses.

The salt spray test is a standardized and popular corrosion test method, used to check corrosion resistance of materials and surface coatings. Usually, the materials to be tested are metallic and finished with a surface coating which is intended to provide a degree of corrosion protection to the underlying metal.

<span class="mw-page-title-main">Microbial loop</span>

The microbial loop describes a trophic pathway where, in aquatic systems, dissolved organic carbon (DOC) is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by phytoplankton-zooplankton-nekton. In soil systems, the microbial loop refers to soil carbon. The term microbial loop was coined by Farooq Azam, Tom Fenchel et al. in 1983 to include the role played by bacteria in the carbon and nutrient cycles of the marine environment.

<span class="mw-page-title-main">Aquarium</span> Transparent tank of water for fish and water-dwelling species

An aquarium is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquatic reptiles, such as turtles, and aquatic plants. The term aquarium, coined by English naturalist Philip Henry Gosse, combines the Latin root aqua, meaning 'water', with the suffix -arium, meaning 'a place for relating to'.

<span class="mw-page-title-main">Marine snow</span> Shower of organic detritus in the ocean

In the deep ocean, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below, which is referred to as the biological pump. Export production is the amount of organic matter produced in the ocean by primary production that is not recycled (remineralised) before it sinks into the aphotic zone. Because of the role of export production in the ocean's biological pump, it is typically measured in units of carbon. The term was coined by explorer William Beebe as observed from his bathysphere. As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthetic activity and ocean currents. Marine snow can be an important food source for organisms living in the aphotic zone, particularly for organisms that live very deep in the water column.

<span class="mw-page-title-main">Outline of water</span> Overview of and topical guide to water

The following outline is provided as an overview of and topical guide to water:

Deuterium-depleted water (DDW) is water which has a lower concentration of deuterium than occurs naturally at sea level on Earth.

<span class="mw-page-title-main">Viral shunt</span>

The viral shunt is a mechanism that prevents marine microbial particulate organic matter (POM) from migrating up trophic levels by recycling them into dissolved organic matter (DOM), which can be readily taken up by microorganisms. The DOM recycled by the viral shunt pathway is comparable to the amount generated by the other main sources of marine DOM.

Charles Remington Goldman is an American limnologist and ecologist.

Cindy Lee is a retired Distinguished Professor known for her research characterizing the compounds that comprise marine organic matter.

References

  1. Kester, D. R., Duedall, I. W., Connors, D. N. and Pytkowicz, R. M. (1967). Preparation of Artificial Seawater Archived 2008-12-17 at the Wayback Machine . Limnology & Oceanography12, 176–179.
  2. Goldman, J. C. and McCarthy, J. J. (1978). Steady-state growth and ammonium uptake of a fast-growing marine diatom Archived 2008-12-17 at the Wayback Machine . Limnology & Oceanography23, 695–703.
  3. "Standard Practice for the Preparation of Substitute Ocean Water". ASTM International. Retrieved 16 June 2014.
  4. "ASTM D1141-98 Standard Practice for Preparation of Substitute Ocean Water". ASTM International.
  5. ""Artificial Seawater" ASTM D1141-98 Lake Products Company LLC".
  6. "Preparation of Substitute Ocean Water". G2MT Labs. 2018-11-08. Retrieved 10 November 2018.