Hydrosphere

What is Hydrosphere?
The hydrosphere is the combined mass of water found on, under,
and above the surface of the earth. It has been estimated that there
are 1386 million cubic kilometres of water on earth. This includes
water in liquid and frozen forms in groundwater, oceans, lakes and
streams. Approximately 75% of Earth’s surface, an area of some 361
million square kilometres, is covered by ocean.
Oceans, lakes, rivers, underground water, streams, ice lands
and water vapour in the atmosphere are collectively called the
hydrosphere.

Hydrological Cycle/Water Cycle

The hydrological cycle transfers water from one state or reservoir to
another.
There are four steps in the Water cycle. Those are evaporation,
condensation, precipitation and surface run-off.
 1. Evaporation : Water from lakes, oceans, streams, etc.
evaporates by the sun’s heat. This transformation of state from
liquid to gas is called evaporation.
2. Condensation; Water vapour carried away by hot air starts to
cool when it goes higher from the earth’s surface. Later it
transforms in the form of clouds. This process is known as
condensation.
3. precipitation : When the water accumulates in the clouds, it
becomes heavy and starts to fall back in the form of snow or rain
depending upon the temperature of the atmosphere. This process is
known as precipitation.
4. surface run-off : When it rains, a small quantity of water is
absorbed by the soil and becomes groundwater. The remaining part
flows through the hills, mountains and is collected in different parts
of the hydrosphere. This process is termed as surface run-off.

Most evaporation comes from the oceans and is returned to the

earth as snow or rain.
Importance of Hydrosphere
As we all know, the survival of living organisms without water is
impossible. Life on the earth entirely depends upon water. Hence
earth is known as a water planet. Hydrosphere plays a vital role in
our daily life. A few importance of hydrosphere are as follows:

1. One of the Basic Needs of Human

Apart from drinking, water is essential for cooking, cleaning,
washing and even for the functioning of so many industries. In
addition to this, water is necessary for agriculture and the
generation of electricity through hydropower. It is difficult to
imagine a day without water.

2. Part of a Living Cell

The main component in the cells of all living organisms is water. It is
found that 75% of the cell is composed of water. Most of the
chemical reactions occurring in the cells are mainly due to the
presence of water. Survival of a cell is impossible without water. In
plants, the energy transportation is done with the help of these
water molecules only.

3. Habitat for Many Organisms

Hydrosphere is the habitat for numerous aquatic plants and
animals. The number of living organisms in water is high when
compared to the number of organisms that are living on land.

4. Regulates Temperature
One of the important features of the hydrosphere is that it helps to
regulate the temperature of the environment. Water takes time to
heat as well as to cool. So the places surrounded by water bodies
like oceans and lakes tend to have a balanced climate.

5. Atmosphere Existence
Hydrosphere plays an important role in the present form of
atmosphere. Above 400 million years ago, the earth’s atmosphere
was covered with helium and hydrogen. Earth’s atmosphere was
very thin and was similar to the planet Mercury’s present
atmosphere and the temperature was around 600°C. Later on,
when the earth's surface cooled and as a result of so many chemical
reactions, the water bodies and atmosphere formed in massive
amounts.

Uses of Water
1.We all use water for drinking, cooking, bathing, cleaning, washing,
etc.
2.Factories and large industries use water in large quantities for
producing various products required for human welfare.
3.Farmers also use water for irrigating and cultivating crops.
Thus, water is necessary for many activities; therefore, it is
an essential requirement of life.

Why is water essential to the human body?

Water serves as an essential nutrient to our body, and it plays a vital
role in the following:
• Lubricates joints
• Maintains the body temperature
• Removes toxins and other wastes from the body
• Moistens the tissues of the eyes, nose and mouth
• Transportation of nutrients and oxygen to different cells,
tissues and organs.

Sources of water
The major sources of water include:
1. Groundwater:
1. Any water source below the soil layer is referred to as
groundwater.
2. Groundwater can be found in the soil or in the spaces between
rocks and other materials
3. Among these 30% is groundwater.
2. Surface-water:
1. Surface water refers to the source of water that is found above
the ground such as rivers, ponds, lakes, and oceans.
2. 80 percent of water used by humans is surface water.
3. Rainwater:
1. It is one of the major sources of water that is the result of
evaporation, condensation, and precipitation (water cycle).
2. Rainwater can be reused by adapting the method called
rainwater harvesting.

Aquatic Ecosystem
The aquatic ecosystem definition states it is a water-based
environment, wherein, living organisms interact with both physical
and chemical features of the environment. These living creatures
whose food, shelter, reproduction, and other essential activities
depend on a water-based environment are known as aquatic
organisms.

Types of Aquatic Ecosystem

there are two types of aquatic ecosystems, namely marine
ecosystems and freshwater ecosystems
1. Freshwater Ecosystem
• Freshwater ecosystems only cover about 1 percent of the
earth's surface.
• Lakes, ponds, rivers and streams, marshes, swamps, bogs, and
ephemeral pools are all examples of freshwater.
• Freshwater ecosystems are divided into three types: lotic,
lentic, wetlands, and swamps.

(a) Lotic Ecosystems

Lotic ecosystems primarily refer to unidirectionally flowing, quickly
flowing waterways such as rivers and streams.
(b)Lentic Ecosystems : They encompass all ecosystems with
standing water.
(c)Wetlands and Swamps : A swamp is an area in the forest that is
permanently filled with water.If there is no forest around, then it is
termed as a wetland.
•
2. Marine Ecosystem
• The marine environment spans the majority of the earth's
surface area.
• Oceans, seas, the intertidal zone, reefs, the seabed, estuaries
• Aquatic animals cannot exist outside of water.
• Their bodies are designed to survive in saltwater and will swell
if placed in less salty water
(a)Ocean Ecosystems
The Pacific, Indian, Arctic, and Atlantic Oceans are the five primary
oceans on earth
(b) Estuaries
Estuaries are critical forms of natural habitats which are typically
formed where the sea and the rivers meet.
(c) Coral Reefs
Coral reefs are underwater structures built from the skeletons of
marine vertebrates,
(d) Coastal Systems
Coastal ecosystems are made up of open systems of land and water
that are linked together.
Uses of Water
Water can be used for direct and indirect purposes. Direct purposes
include bathing, drinking, and cooking, while examples of indirect
purposes are the use of water in processing wood to make paper
and in producing steel for automobiles. The bulk of the world’s
water use is for agriculture, industry, and electricity. The most
common water uses include:
• Drinking and Household Needs
• Recreation
• Industry and Commerce
• Agriculture
• Energy
Properties of Water
1.Water is the chemical substance with chemical formula H2O; one
molecule of water has two hydrogen atoms covalently bonded to a
single oxygen atom.[25]
2.Water is a tasteless, odorless .
3. It has capacity to dissolve salt, sugar &other solvents.
4. The freezing point is 00c.
5. The boiling point is 99.980c

Water Pollution
Water pollution can be defined as the contamination of water
bodies. Water pollution is caused when water bodies such as rivers,
lakes, oceans, groundwater and aquifers get contaminated with
industrial and agricultural effluents.
When water gets polluted, it adversely affects all lifeforms that
directly or indirectly depend on this source. The effects of water
contamination can be felt for years to come.
Sources Of Water Pollution
The key causative of water pollution in India are:
• Urbanization.
• Deforestation.
• Industrial effluents.
• Social and Religious Practices.
• Use of Detergents and Fertilizers.
• Agricultural run-offs- Use of insecticides and pesticides.
Water Pollution – A Modern Epidemic

One of the primary causes of water pollution is the contamination

of water bodies by toxic chemicals. As seen in the example
mentioned above, the dumped plastic bottles, tins, water cans and
other wastes pollute the water bodies. These result in water
pollution, which harms not just humans, but the whole ecosystem.
Toxins drained from these pollutants, travel up to the food chain
and eventually affect humans. In most cases, the outcome is
destructive to only the local population and species, but it can have
an impact on a global scale too.
The Causes of Water Pollution
There are many causes of water pollution. Below, we will focus on
seven of the major ways that water can become polluted.
1. Industrial Waste
Industries and industrial sites across the world are a major
contributor to water pollution. Many industrial sites produce waste
in the form of toxic chemicals and pollutants, and though regulated,
some still do not have proper waste management systems in place.
In those rare cases, industrial waste is dumped into nearby
freshwater systems. When industrial waste is not treated properly
(or worse, not treated at all), it can very easily pollute the
freshwater systems that it comes into contact with.

It make water unsafe for human consumption, they can also cause
the temperature in freshwater systems to change.

2. Marine Dumping
The process of marine dumping is exactly what it sounds like,
dumping garbage into the waters of the ocean. It might seem crazy,
but household garbage is still collected and dumped into oceans by
many countries across the world.

3. Sewage and Wastewater

Harmful chemicals, bacteria and pathogens can be found in sewage
and wastewater even when it’s been treated. Sewage and
wastewater from each household is released into the sea with fresh
water. The pathogens and bacteria found in that wastewater breed
disease, and therefore are a cause of health-related issues in
humans and animals alike.
4. Oil Leaks and Spills
The age-old phrase “like water and oil” is used when describing two
things that do not mix easily or at all. Just as the saying states,
water and oil do not mix, and oil does not dissolve in water. Large
oil spills and oil leaks, while often accidental, are a major cause of
water pollution. Leaks and spills often are caused by oil drilling
operations in the ocean or ships that transport oil. wildlife.
5. Agriculture
In order to protect their crops from bacteria and insects, farmers
often use chemicals and pesticides. When these substances seep
into the groundwater, they can harm animals, plants and humans.
Additionally, when it rains, the chemicals mix with rainwater, which
then flows into rivers and streams that filter into the ocean, causing
further water pollution.
6. Global Warming
Rising temperatures due to global warming are a major concern in
terms of water pollution. Global warming causes water
temperatures to rise, which can kill water-dwelling animals.
7. Radioactive Waste : While creating nuclear energy radioactive
waste can be hazardous to the environment must be disposed of
properly. Uranium, the element of creation of nuclear energy is
highly toxic.
Pollutants
The following are general categories of drinking water contaminants
and examples of each:
 Physical contaminants primarily impact the physical
appearance or other physical properties of water. Examples of
physical contaminants are sediment or organic material
suspended in the water of lakes, rivers and streams from soil
erosion.
 Chemical contaminants are elements or compounds. These
contaminants may be naturally occurring or man-made.
Examples of chemical contaminants include nitrogen, bleach,
salts, pesticides, metals, toxins produced by bacteria, and
human or animal drugs.
 Biological contaminants are organisms in water. They are also
referred to as microbes or microbiological contaminants.
Examples of biological or microbial contaminants include
bacteria, viruses, protozoa, and parasites.
 Radiological contaminants are chemical elements with an
unbalanced number of protons and neutrons resulting in
unstable atoms that can emit ionizing radiation. Examples of
radiological contaminants include cesium, plutonium and
uranium.

Effects Of Water Pollution

The effect of water pollution depends upon the type of pollutants
and their concentration. Also, the location of water bodies is an
important factor to determine the levels of pollution.
• Water bodies in the vicinity of urban areas are extremely
polluted. This is the result of dumping garbage and toxic chemicals
by industrial and commercial establishments.
• Water pollution drastically affects aquatic life. It affects their
metabolism, and behaviour, and causes illness and eventual death.
• The effect of water pollution can have a huge impact on the
food chain. It disrupts the food chain. Cadmium and lead are some
toxic substances, these pollutants upon entering the food chain
through animals (fish when consumed by animals, humans) can
continue to disrupt at higher levels.
• Humans are affected by pollution and can contract diseases
such as hepatitis through faecal matter in water sources. Poor
drinking water treatment and unfit water can always cause an
outbreak of infectious diseases such as cholera, etc.
• The ecosystem can be critically affected, modified and
destructured because of water pollution.

Pollution of the Ganges—Case study

Some rivers, lakes, and groundwater are rendered unfit for usage.
In India, the River Ganges is the sixth most polluted river in the
world. This is unsurprising as hundreds of industries nearby release
their effluents into the river. Furthermore, religious activities such
as burials and cremations near the shore contribute to pollution.
Apart from the ecological implications, this river poses a serious
health risks as it can cause diseases like typhoid and cholera.
Pollution of the Ganges is also driving some of the distinct fauna to
extinction. The Ganges River shark is a critically endangered species
that belong to the order Carcharhiniformes. The Ganges River
dolphin is another endangered species of dolphin that is found in
the tributaries of the Ganges and Brahmaputra rivers.

Four steps to control water pollution

Step 1: Implementing Control measures
This is the first step of the process, and strict control measures
should be implemented for the activities causing water pollution.
The community should reduce activities such as plastic usage and
sewage dumping. There are many things that society can do to
implement control measures for water pollution.
Step 2: Wastewater treatment
This is the next step in controlling water pollution. We can control
water pollution by reducing the proportion of wasted water. The
pollutants should be removed from water through chemical,
biological or physical treatments.
Step 3: Purification
Further, water purification initiatives should be carried out
thoroughly to destroy the pollutants and harmful elements from
water to a substantial extent.
Step 4: Spreading awareness
After all these three steps, spreading awareness and raising public
consciousness for better participation in reducing water pollution
are necessary steps. The combined initiatives from all communities
to reduce water pollution can increase or maintain water quality in
the long run.
Problems of the hydrosphere
Water pollution,
river damming, wetland drainage,
climate change, and
irrigation have all changed the hydrosphere.

Conservation of Water
Conservation of water mainly refers to protect, preserve, and control
the usage of water and its resources. It is the system introduced to
manage freshwater, reduce the wastage and protect the water and its
resources.
There are several ways to conserve water. Here are some important
and easy ways for the conservation of water
 Keeping the tap closed when not in use.
 Check for the openings or leaks in water distribution pipes.
 Make sure to use collected rainwater for gardening or washing
purpose.
 Always have a measure of how many buckets of water is wasted
in a day and try to reduce.
 Do not run more water than necessary while washing and
cleaning clothes, utensils, etc.
 Do not prolong your bathing. Go for a quick shower rather than
wasting buckets of water
 Rainwater harvesting is one of the best method used for
conserving water. There are different methods used to preserve
rainwater instead of getting it wasted.
Rainwater Harvesting Diagram
Rainwater harvesting is the simple process or technology used to
conserve rainwater by collecting, storing, conveying and purifying of
rainwater that runs off from rooftops, parks, roads, open grounds,
etc. for later use.
Here, let us have a look at the diagram of rainwater harvesting
system.