The hydrosphere is a term designating all the areas of a planet where water is present.
It concerns water in all its forms, liquid(oceans, rivers, groundwater...), solid(eternal snows, glaciers, ice floes...),or in gaseous form with water vapor!
There is therefore a cross-over with the notions of cryosphere for water in the solid state, and the atmosphere for water vapor!
The volume of terrestrial hydrosphere is estimated at about 1.5 billion cubic kilometers, of which 93.9 % is in the oceans, which cover about three-quarters of the earth's surface.
Its total mass is estimated at
1 385 990 800 million tonnes.
This is equivalent to about 0.023 % of the total mass of the Earth.
The terrestrial hydrosphere consists of approximately 97 % salt water with sodium(Na +) and chlorine (Cl-) ions.
The terrestrial hydrosphere would be relatively stable.
Every year, the Earth loses about
90,000 tons of hydrogen in space and gains about 50,000 tons of various materials, some of which is water!
Water having a high specific heat, the hydrosphere constitutes an enormous reservoir of heat and its thermal inertia and its currents influence the climates and the winds of the Earth.
One realizes this by remembering that the latitude of Montreal, New York, and Bordeaux are sensibly at the latitude of Barcelona; However, the usual winters of the two cities of the Americas being inconsistent with those of their European counterparts.
The water of the hydrosphere is in perpetual motion:
Currents, waves and tides agitate seas, lakes and rivers, glaciers slip on the continents, icebergs sail adrift, driven by winds and currents, thousands of rivulets infiltrate the rock, digging Caves and loading themselves with salt while they run towards the sea.
The hydrosphere models the lithosphere by eroding it, but also by transporting the debris and accumulating it to the point of forming new geological structures.
The seas are large masses of salt water determined by archipelagos, large islands or peninsulas or by relatively close land.
The oceans, much larger, separate the continents and reach a much greater depth.
The continents are extended under the water by a continental platform of about 200meters deep!
This platform ends by a steep drop, the continental slope, which reaches the great depths towards 3000 m depth!
Although the oceans and seas communicate with each other, their salinity, density and temperature are different.
Thus the tropical waters are more saltythan the waters where the great rivers flow, and the cold seas because of the greater evaporation, or because the salts dissolvesbetter in hot water.
The highest salinity is found in the RedSea (44 g / L on average and up to 300 g / L locally), the lowest in the Baltic Sea(2 g / L) with an average salinity of 35 g/ L!
There are two large zones of relatively homogeneous depth and characteristics:
The euphotic zone and the aphotic zone!
Concerning the euphotic zone:
The term euphotic comes from the Greek "eu" (good) and photos (light).
It is a shallow area, where light still arrives, where many plants live and where oxygenation is maximum.
It is divided into a hemi-peleagic zone(0 to 50 meters deep) and in a mesopelagic zone (-50 to -200 m) that only the ultraviolet reaches and the only plants are red and brown algae!
The aphotic zone encompasses everything else!
The darkness is total, the infra-pelagic zone(-200 to -600m) is distinguished,
enriched in nutrients by the proximity of the coasts and the euphotic zone populated by numerous animal species;
The bathypelagic zone(-600 to -2500m), which comprises most of the waters and where only large carnivores and species adapted to the depths live;
And finally the abyssopelagic zone(-2500m and more ), almost deserted!
The pressure increases with the depth of about 1000 hectoPascal every 10 meters.
At 200m below sea level, each square centimeter must support 1,023kg.
The temperature decreases irregularly and differently according to latitude.
At the equator it is on average 30 degrees C to the surface, 15 degrees C to -250 m, 8degrees to -500 m, 5 degrees C to -1000 m and stabilizes between 5 and 0 degrees C to -4000 m!
Thus the temperature commonly found on the surface at the poles is found only 4000 m deep at the equator!
In addition, more than 90% of the world's water is in the oceans, which have an average depth of 3800m!
Finally, the inland seas and lakes are important reservoirs of more or less sweet water.
Depending on their origin, there are:
The glaciers(of elongated and irregular shape) resulting from the melting of old glaciers,
Tectonics(irregularly shaped) formed by movements of the earth's crust, such as the Dead Sea,
The coastal(formed of brackish water),
The Karstics(occupying the clay depressions),
Residual lakes, which are remnants of ancient seas or gulfs, such as the CaspianSea,
The alluvial originated by the massive fall of rain,
And finally, the dams, whether natural or artificial, that the engineer, or the architect was a beaver or a man!
Rivers are fed by atmospheric precipitation via torrents or melting glaciers and are characterized by a permanent flow of water!
The amount of water that passes through a section of a water course at every second is called its flow.
It is measured in cubic meters of water/ sec.
Maximum flow during flooding and minimum during low water.
The region covering all the tributaries of a river constitutes its watershed!
The three main satellites of Jupiter also have notable hydrospheres!
Europe, whose surface is covered with ice, presented a subglacial ocean a hundred kilometers deep under the entire ice watercrust
Ganymede would probably have a hydrosphere analogous to that of Europe with the presence of an ocean caught between two layers of ice.
Callisto could also have an ocean under its surface!
Finally, Gliese 581 c, which is the most similar known exoplanet to the Earth, gravitating in the habitable area of Gliese 581,
has an average temperature which could be between 0 degree and 40 degree celcius, which would allow the presence of Water in the liquid state on its surface!
The biosphere is the set of living organisms and their living environments!
The biosphere is the totality of the ecosystems present in the lithosphere, the hydrosphère and the atmosphere!
The presence of water and photosynthesis are an essential element and mechanism of the biosphere!
The biosphere or symbiosphere(which is an expression invented by Joel Fromet de Rosnay, French scientist and writer) is the planetary level of integration of all the scales of the Alive!
This pyramid goes from the gene to the sum of the biomes, without which the oxygene and therefore the ozone layer would not exist!
The gene is represented separately because it is not alive as such, but it supports the information and the basis of the living.
The more you climb into the pyramid, the more global the scale is, and the more complexity but also the stability and resilience of the system seems to increase!
The holistic and interdisciplinary biosphere concept has gradually been associated
with astronomy, geophysics, meteorology, biogeography, evolutionary biology, geology, geochemistry, ecology and in a general way all that is related to The Earth and the living.
Geochemists also give the term biosphere the meaning of the total sum of living organisms, which is commonly called biomass or biota by biologists and ecologists.
According to this definition, the biosphere is one of the four constituents of the geochemical model, with the lithosphere, the hydrosphere and the atmosphere!
Some believe that the semantic and conceptual vagueness surrounding the term biosphere is reflected in the current debates on biodiversity, or sustainable development...
According to them, the use of the term biosphere derived from the vocabulary of geochemists would be a consequence of the highly specialized organization of current science.
As a painter, I deplore it... the specialists always end up lacking in "height" and holistic "vue"!
Some now, prefer the term "ecosphere", which dates back to the 1960s-70s, when the notion of an ecological crisis that threatened the whole biosphere appeared!
James lovelock also proposed the name "symbiosphere" to emphasize the interdependence between the species and the whole that they constitute.
Finally, it was Vernadsky who defined ecology as the science of the biosphere in 1926!
Name dropping when you hold us!
The biosphere is the global, self-sustaining, or autocatalytic ecological system.
It integrates all living beings and the relationships they create between themselves and with the compartmentsof the lithosphere(rocks),
The hydrosphere(water), and the atmosphere (air), in a metabolism that continually transforms the surface of the Earth by recycling or storing the elementsand creating complexity.
The concept of the biosphere intersted, in a religious context, Teilhard de Chardin, a French Jesuit priest, a researcher, a paleontologist, a philosopher, and a theologian.
He also used the term "noosphere", constituted by the human phenomenon, above the biosphere.
Beyond the beliefs, understanding the concepts of modern scientific ecology has popularized the appellation
and developed the perception of the environment of planetEarth, host of the biosphere!
Moreover, the deep biosphere is the deepest and underwater part of the biosphere and probably the least known!
It consists essentially of bacteria, arches(archeobacteria), and marine virusesadapted to life in extreme conditions.
The exchanges between the different envelopes of the Earth are multiple, complex and permanent.
Life on our planet is closely linked to the atmosphere, as a reservoir of chemical elements like carbon, hydrogen, oxygen, nitrogen, sulfur...
The atmosphere is a privileged stage of the circulation of the abiotic chemical elements used for the edification of living beings!
Indeed, living organisms need about fortyelements to synthesize their own matter
Carbon( C ), nitrogen( N ), hydrogen( H ), oxygen(O ), sulfur and phosphorus!
These are the most important because they constitute the essential part of livingmatter; They alone account for about 95 % of the atomic make-up of living beings.
Macroelements such as potassium, calcium, magnesium, sodium...
They are necessary in "relative" large quantity.
Trace elements like zinc, copper... needed in very small quantities.
These elements pass alternately from livingmatter to mineral matter through cycles of varying length and complexity: biogeochemical cycles.
A given element can thus pass through the biosphere, along the food chains, to find itself in the atmosphere ...
Then in the oceans, be stored for very long periods in sediments before being released and reused again by living organisms!
It must be emphasized, however, that the biogeochemical cycles of these various elements do not necessarily pass through the atmosphere such as phosphorus, for example.
In addition, we must mention the essential role of water( H2O ) whose cycle intervenes in almost all the mechanisms intervening on Earth: climate, erosion, life...
Oxygen and carbon constitute 83.5 % of the atoms of the human body.
Organized in molecules with hydrogen and nitrogen, they constitute the major part of the organic matter characteristic of livingbeings.
The carbon atom has very special characteristics:
On the one hand, it behaves like a neutralatom capable of combining with electropositive atoms and electronegativeatoms;
On the other hand, each carbon atom is capable of forming four bonds with other atoms and about one million different compounds of carbon are presently listed.
In addition, carbon and oxygen play a predominant role in the energy mechanisms essential to living beings.
From an energy point of view, there are two types of living things:
Autotrophs, which are organisms capable of building their own material from the various mineral elements of their environment.
For example, during photosynthesis, chlorophyll plants are able to form their organic matter from carbon dioxide(CO2), water and mineral salts, using light energy.
Dioxygen released into the atmosphere can be considered a waste of photosynthesis.
Heterotrophs, which are organisms that elaborate their organic matter from moleculesmade by other living or dead beings.
They use them as raw materials and as a source of energy for two different mechanisms:
Fermentation in an anaerobic(dioxygen free) environment in which organic molecules are degraded incompletely and with release of CO2,
such as the transformation of glucose into ethanol during the alcoholic fermentation carried out by certain bacteria.
Aerobic respiration(with dioxygen) in which all energy molecules are degraded to CO2 and H2O that are released to the atmosphere,
such as during the transformation of glucose during animal or plant respiration.
The yield of respiration is much higher than that of fermentation!
Thus, the degradation of one mole of glucose released has nearly 45 times more energy during breathing than during fermentation.
So breathe, rather than rot!
The chemical composition of the atmosphere is determined by constant exchanges between the four reservoirs or spheres of the terrestrial environment: the atmosphere, the hydrosphère with the oceans, the lithosphere for the soil and the rocks of the subsoil, And finally the biosphere!
The different elements are permanently recycled, moving continuously from one sphere to the other, under the influence of various processes!
Carbon, which is in finite quantity on Earth is continually recycled!
It is present on Earth in different réservoirs and in various forms.
The tanks presented are initially the atmosphere with carbon in the form of carbon dioxide and the biosphere composed of organic matter, then dissolved forms and carbonates of the hydrosphere.
The last reservoir presented is the lithosphere in which we find carbonaceous rocks and sedimentary rocks!
There are two cycles of carbon, a shortcycle, and a long cycle!
The short cycle is directly related to the living.
It is limited to surface exchanges through the mechanisms of photosynthesis, respiration and fermentation, both at the continental and oceanic levels.
To enter the long cycle you have to change the time scale and count in millions of years!
The long cycle concerns calcareous rocks and sediments whose rise depends on tectonic movements.
The idea of long-term carbon capture by the lithosphere is illustrated by the example of coal and petroleum,
as well as a slow enrichment of the atmosphere with carbon dioxide by volcanic activity.
There is an annual equilibrium of the shortcycle flows betwen the biosphere and the atmosphere.
The equilibrium of the long cycle is also realized but on a geological time scale!
The contents of the tanks therefore remain substantially constant.
For 10,000 years and until 1850, the amount of atmospheric carbon dioxide has remained stable around 275 parts per million.
Since 1850, the concentration has increased from 275 ppm to 393 ppm in January 2012... human action is responsible!
The main factors are the use of fossil fuels, the transformation of limestones to make cement without forgetting deforestation.
Increasing the atmospheric carbon dioxide content increases the greenhouse effect and increases the temperature.
While the exodus CO2 absorption is constant in the oceans( 26 %), the same magnitude is variable at continental level (20 % to 78 %) depending on the year!
Atmospheric oxygen, although it may result from the dissociation of water, is essentially of phosynthetic origin.
As a result, the oxygen cycle is often associated with that of the carbon to which it is antiparallel in its main path: combustion and respiration deplete the oxygen that is reconstituted by photosynthesis.
In fact, the oxygen cycle, because of its ability to participate in multiple chemical combinations is very complex.
For example, the formation of ozone(3O2<-> 2O3 ), or the oxidation of minerals such as iron ( 4FeO + O2 -> 2FeO3)...
The oxygen cycle is a biogeochemical cycle that explains the transformations of oxygen in the terrestrial biosphere.
It is inseparable from the carbon cycle,because carbon dioxide is used during photosynthesis.
The latter produces dioxygen, which, through respiration, burns the carbon components produced by photosynthesis to give back carbon dioxide.
Photosynthesis and respiration are at the origin of the production and the equilibrium of atmospheric gases.
The two mechanisms CO2 + H2O -> sugars + dioxygen and vice versa, condition the circulation of carbon and oxygen.
This cycle explains the phenomenon of the appearance of ozone.
The use of cars emits nitrogen dioxide(NO2).
This, by decomposition and then recomposition with the ambient dioxygen(O2), forms ozone(O3).
However, this ozone is detrimental to health and is even considered a pollutant.
However, in the upper atmosphere, ozone forms a layer which is essential, indeed it acts as a filter with respect to the UV emitted by the sun.
Thus, and in a simplified manner, we have:
NO2 -> NO + O
O + O2 → O3.
The love of formulas....