La salinité des océans influence le climat, aujourd'hui comme dans le passé de la Terre. © peangdao, Adobe Stock

The salt of the oceans would have played a role in the habitability of the earth

The composition ofthe atmosphere has a direct impact on the climate, that is now taken for granted. The multitude of paleoclimatic studies has also highlighted the great influence of atmospheric composition on the evolution of the Earth’s climate, and has done so since the formation of the structure of the globe…” data-image=”https ://cdn.futura- /images/midioriginal/8/4/f/84ff7edce5_123534_terre-apollo8.jpg” data-url=” earth-earth-4725/” data-more=” Read more”>Earth. However, the composition of the oceans played an equally important, even decisive role in maintaining favorable climatic conditions for the emergence of life at the dawn of our planet’s history. The chemical exchange between the ocean and the atmosphere is indeed very intense and allows the regulation of certain processes, especially at the level of “ f/b9f0872ae1_50084221_ges2011-poilaumenton-flickr-01.jpg” data-url=” planete/definitions/climatology-gas-greenhouse-effect-5381/” data-more=”Read more”>greenhouse gases. In this context, the amount of salt in the oceans would be a non-negligible factor.

The salinity of the oceans influences the climate

Ocean salinity and climate are two related parameters. If that’s what it’s currently about the influence of climate on salinity due to global warming and the evaporation caused by this, the opposite is also true: the salinity is one of …” data-image=” – mesure-salinite-captain-robert-pawlowski-noaa.jpg” data-url=”” data-more=”Read more”>salinity of the oceans has the ability to influence the climate. That shows a new study published in the journal Geophysical Research Letters.

The oceans have the ability to store gases in dissolved form. This is especially true for CO2 we talk about it so much right now. However, the solubility of gases in water is closely related to the concentration of monatomic and polyatomic ions, cations and anions.
Ions can be monatomic if they consist of only one type of atom, or polyatomic…” data-image=” /2/d/ 3/2d3b08d8ec_100849_ion- definition.jpg” data-url=”” data-more=”Read more”>ions dissolved in the oceans. Knowing that the salinity of the oceans is defined by the concentration of ions sodium (N / A+) and chloride (Cl) the solubility of gases seems to decrease with increasing salinity: a saline ocean will therefore be less receptive greenhouse gasesthat remain in the atmosphere.

The multiple effects of salt

However, the effects of salt do not stop there. The salinity also directly influences the density of the water (salt water is denser than fresh water), which affects the circulation cycles of the oceans and thereby changes the temperature exchange between water and ocean.Airespecially at the high level Note that one can imagine… data-url=”” data-more=”Read more”>latitudes. As a well-known effect, salt also lowers the freezing point of seawater, preventing the formation of ice on the sea surface. This phenomenon limits the formation of sea ice : The higher the salinity, the lower the temperature must be reached for ice to form.

All of these effects are closely related, and their combination means that variation in salinity can have significant effects on ocean circulation and heat transport. Physicists call heat thermal energy. In the international system, it is therefore measured in joules (J). Heat more closely corresponds to a transfer…” data-image=”” data-url=” https :/ /” data-more=”Read more”>warmth towards high latitudes and on the formation of sea ice. However, even small variations in ice cover can lead to significant climate changes by modifying the reflective surface that ice represents.

A variety of causes can lead to fluctuations in the amount of salt in the oceans: fluctuations in water level, fluctuations in external inputs (rivers, etc.) or cold water level (hence… “Data -image=”https://cdn.futura-sciences .com/buildsv6/images/midioriginal/c/8/7/c878191838_50037682_sechmasource-cnrs.jpg” data-url=” planet /definitions/oceanography-hydrothermal-source-10993/” data -more=”Read more”>hydrothermal ventsIncrease or decrease in the rate of weathering of continental rocks… All of these variables make it easy to imagine that ocean salinity could have changed significantly over the course of Earth’s history.

A saltier Archean ocean would have resulted in a warm climate, despite a sun that was still weak

Based on a climate model that takes into account oceanic and atmospheric dynamics, the team of American scientists show that the more saline the oceans, the warmer the climate. The results of the study suggest that increasing the amount of salt in seawater from 20 to 50 g/kg would result in a 71% reduction in sea ice. These estimates are valid in the current configuration, but also for the past.

During the archaic and its empirical limits
The first forms of terrestrial life, prokaryotes, would have appeared during this period, marked by the appearance…” data-image=” 1/ 4/5146e57183_46763_earth-archeen-charlie-meeks.jpg” data-url=”” data-more=”Read more”>archaiccorresponding to the Earth’s first geological period, the scientists show that the presence of a saltier ocean than the current one could have allowed the maintenance of a warm climate associated with high concentrations of greenhouse gases2 and CH4) in the air. This conclusion is important because at this time of the earth’s youth the The sun was much less bright then (about 20% less than today). Thus, the presence of a very saline ocean could have prevented the Earth from turning into a ball of ice and, in particular, created favorable conditions for the emergence and development of life.

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