Table of Contents
What is hydrosphere?
The hydrosphere is the total amount of water in the Earth’s sphere, i.e., it is the combined total of water on the surface of the earth, underground, and in the atmosphere. All these make up the hydrosphere. It can also be seen as one of the spheres of the Earth along with the biosphere, lithosphere, and atmosphere known as the four spheres of the Earth.
Although the hydrosphere is primarily composed of water, there are some “impurities” or additions to this water, such as dissolved minerals, dissolved gases, and particulates. Some of these cause pollutions, while others are necessary for the health of the ecosystem. Too much sediment, for example, is harmful to the surrounding ecosystems, whereas low levels of dissolved oxygen in the water cause hypoxic conditions that can harm ecosystems. Thus, healthy ecosystems that surround various components of the hydrosphere require a delicate balance, hence the need for a cycle to balance the components of the hydrosphere.
The hydrologic cycle is based on the movement of the hydrosphere and the exchange of water between the hydrosphere and the cryosphere. The constant movement and exchange of water contribute to the formation of currents that transport warm water from the tropics to the poles, thereby helping to regulate the Earth’s temperature. This feature of water exchange makes it an essential component of the hydrosphere.
Definition of the hydrosphere
The hydrosphere can simply be defined as the component of the Earth sphere that contains all of the planet’s liquid water. Oceans, seas, lakes, ponds, rivers, and streams are all examples of water storage areas in the hydrosphere.
Overall, the hydrosphere is vast, with the oceans alone covering roughly 71% of the Earth’s surface area. Because a thorough analysis of the hydrosphere has estimated that the total volume of water on the Earth is 1.36 billion cubic kilometers (332 million cubic miles), which includes liquid and frozen forms of groundwater, oceans, lakes, and streams to mention a few.
Further analysis shows that freshwater accounts for only 2.5 percent of this total, while saltwater accounts for 97.5 percent. However, it is also observed that 68.9 percent of this freshwater is in the form of ice and permanent snow cover in the Arctic, Antarctic, and mountain glaciers. A further breakdown of the freshwater shows that 30.8 percent is in the form of fresh groundwater, and only 0.3 percent is in easily accessible lakes, reservoirs, and river systems.
Definition of hydrosphere in biology
Hydrosphere in biology is defined as the combined mass of water found on, beneath, and on top of a planet’s surface.
What is in the hydrosphere?
- Surface freshwater
- Groundwater freshwater
- Glacial water
- Atmospheric water vapor
The above mentioned are found in the hydrosphere and are briefly described below;
The vast majority of the water on Earth is saltwater, and the oceans hold the vast majority of this saltwater. Some examples of oceans are the Arctic, Southern, Indian, Pacific, and Atlantic Oceans.
This component of the hydrosphere is much less abundant than saltwater and is stored in a variety of locations. The freshwater is divided into surface and groundwater.
A large portion of the Earth’s freshwater flows on the surface of the Earth’s sphere known as surface freshwater. Some of the sources of this type of water are lakes, rivers, and streams.
A small portion of the fresh water on Earth is held beneath the ground or geosphere (another sphere found in the Earth sphere).
This is the water that melts from glaciers.
Atmospheric water vapor
These are evaporated water molecules found in the atmosphere, another sphere of the Earth
Examples of hydrosphere
- The Pacific, Indian, Atlantic, Arctic, and Antarctic oceans are all included as examples of the hydrosphere.
- Seas (the Black Sea, Caspian Sea, Persian Gulf, Adriatic Sea, Mediterranean Sea, and the Red Sea).
- Glaciers, such as the world’s largest glacier, the Lambert Glacier in Antarctica is a great hydrosphere example.
- Another example of the hydrosphere is the clouds.
Facts of hydrosphere
- The total volume of water on Earth is approximately 333 million cubic miles (1,386 million cubic kilometers).
- The hydrosphere is made up of the following percentages of water: 97.6 percent of the ocean, 0.008 percent in saline lakes and inland seas, Glaciers and ice caps account for 1.9 percent of the total, 0.5 percent is for groundwater, 0.01 percent for soil moisture, lakes account for 0.009% of the total water in the Earth’s sphere, 0.0001 percent of freshwater rivers, and 0.0009 percent of the atmosphere.
- Permanent snow contains approximately 68.7 percent of the world’s freshwater and this can be found in the Arctic and Antarctic regions, as well as on mountain glaciers.
- The Earth is known as a water planet because life on Earth is entirely dependent on the water that exists in the hydrosphere.
- The hydrologic cycle is the primary means by which the hydrosphere interacts with the atmosphere and the lithosphere.
- The hydrologic cycle is propelled by solar energy and the water cycle consists of four major steps namely; evaporation, condensation, precipitation, and an additional step known as transpiration, runoff, and infiltration.
- The amount of water on the Earth’s surface, according to scientists, does not change over time. This means that the amount of water available on Earth today is the same as it was when dinosaurs roamed the planet.
- Temperature and pressure are thought to vary significantly with depth in the hydrosphere and the average depth of the Earth’s oceans is said to be 12,447 feet or 3794 meters. This is five times the average height of the continents.
- The Earth’s system is made up of four interconnected or overlapping spheres: the hydrosphere, lithosphere, atmosphere, and biosphere.
- It is estimated that the total mass of water on Earth is approximately 300 times that of the climate.
- According to some scientists, Jupiter’s moon Europa contains another hydrosphere, and t his hydrosphere is made up of a frozen outer layer and a massive liquid layer beneath it.
- The Pacific Ocean is the world’s deepest ocean and it also has the world’s deepest trench, the Mariana trench. The Pacific Ocean is nearly circular, whereas the Atlantic Ocean has an ‘S’ shape and it has the world’s longest coastline.
- There is only one ocean whose name is derived from a country and it is the Indian Ocean, which is deeper than the Atlantic. Furthermore, the Indian Ocean contains more Continental Islands than Volcanic Islands.
- The Arctic Ocean is the world’s tiniest body of water and it is located within the Arctic Circle, with the North Pole in the center.
- The Sun’s and Moon’s gravitational pull causes seawater to expand and contract which causes the surface layer to rise and fall, a phenomenon known as tides. The tides are at their highest during the full and new moons known as spring tides and the lowest tide is known as a neap tide. The neap tide happens during each quarter of the month as a result of the Sun’s vertical relationship to the Moon.
- Ocean currents always flow from east to west as the Earth rotates from west to east and the currents are stronger near the equator, where the Coriolis force is close to zero. The Northern and Southern Oceanic equatorial currents generate a counter-equatorial current, which fills the water void. Similarly, countercurrents, similar to equatorial currents, frequently flow beneath from polar to equatorial regions.
- The hydrosphere, like the environment, is thought to be in constant motion.
- Human activities are influencing the Earth’s hydrosphere and the water cycle.
- Rivers, which are vital to the water cycle, are diverted and dammed by humans.
- Humans are depleting groundwater sources faster than the water cycle can replenish them.
Characteristic of hydrosphere
- It is the layer that encompasses the earth.
- Its physical state is constantly changing as the water within it circulates.
- It requires the sun to change the state of the water.
- The seas have a salinity of 35 gr/l.
- Its temperature varies according to latitude and depth.
- Its density is affected by salinity.
- Water contains the same gases that are found in the air.
The above listed are some of the hydrosphere’s characteristics.
Importance of hydrosphere
- The hydrosphere is the source of water and water is a substance found in living cells.
- Home to many life forms
- Helps in Climate Control
- Part of Atmosphere Existence
- An important human requirement
The hydrosphere is extremely important because it is essential to the survival of all life forms. The hydrosphere performs the following important functions on Earth as discussed below.
A Substance Found in Living Cells
In each living cell, there is at least 75% water that promotes the cell’s normal functioning. The majority of chemical reactions in living organisms involve materials that are dissolved in water. Without water, no cell would survive or be able to carry out its normal functions. The hydrosphere houses the water and serves as a source and reservoir of water to living organisms.
Home to many life forms
The hydrosphere is home to a wide variety of plants and animals, for example, water dissolves many nutrients such as nitrate, nitrite, and ammonium ions, as well as gases such as carbon dioxide and oxygen that are critical compounds to the survival of life in water.
Aids in Climate Control
Water has a high specific heat, which is one of its distinguishing characteristics. Water, in particular, takes a long time not only to heat up but also to cool down this is important in regulating temperatures on Earth, ensuring that temperatures remain within a range suitable for the existence of life. Ocean currents are also important in heat dispersion.
The hydrosphere contributes significantly to the existence of the atmosphere in its current form, for instance, when the earth was formed, it had only a thin atmosphere. This atmosphere, like Mercury’s current atmosphere, was densely packed with helium and hydrogen, then helium and hydrogen were eventually ejected from the atmosphere. This was a result of the cooling of the Earth’s sphere and introducing water vapor and other gasses in the process. Other gases and water vapor were also released by the volcanoes and entered the atmosphere and this process is thought to have occurred approximately 400 million years ago.
Humans benefit from the hydrosphere in a variety of ways. Aside from drinking, water is used for cooking and cleaning, as well as for industrial purposes it can also be used for transportation, agriculture, and hydropower to generate electricity.
Structure of hydrosphere
The hydrosphere is made up of all of the earth’s waters, including water that is liquid, such as that found in oceans, seas, rivers, lakes, streams, and groundwater; solid-state water exists in Antarctica, the Arctic, and glaciers, and lastly, water vapor a type of gaseous water is found in the atmosphere and the ocean is the largest source of water vapor because it holds over 70% of the world’s water.
Human Influences on the Hydrosphere
Humans have significantly altered the hydrosphere in recent history. It has been altered by water pollution, river damming, wetland drainage, climate change, and irrigation. The release of fertilizers and sewage into water storage areas has caused eutrophication, which has artificially enriched aquatic environments with nutrients resulting in excessive algal blooms that cause dangerous hypoxic conditions in the water. Acid rain on the other hand is caused by SOx and NOx emissions from fossil fuel combustion has acidified hydrosphere components, harming surrounding ecosystems.
On a whole, when humans alter the natural flow of water in the hydrosphere by diverting and damming rivers, they harm the ecosystems that rely on the water source. This can also cause some aquatic areas to dry out and excessive sediment to enter streams and rivers.
Effect of the hydrosphere on climate
The hydrosphere’s properties and motion are critical in maintaining the world’s diverse climates; for example, the ocean, which contains 97 percent of the water on Earth, is critical to the climate system and it acts as a reservoir, influencing how much solar radiation is absorbed. Because the ocean is so vast, it absorbs a large amount of solar energy which helps to reduce ultraviolet rays and keep the Earth’s sphere cool, calm, and collected. The ocean is also important to the climatic system because it limits how quickly the climate can change as it serves to redistribute energy and heat around the world, contributing to the various average temperatures that exist around the world.
What is in the hydrosphere?
- Surface freshwater
- Groundwater freshwater
- Glacial water
- Atmospheric water vapor
The above-mentioned are found in the hydrosphere.