Water Ecosystem

One should understand what is ecosystem first in order to understand the concept of water ecosystem and its importance.


The biological environment with all the living and non living organisms in a specific area is known as ecosystem. All the organisms that inhabit a particular area are known to be community. These eco systems could either be permanent or temporary. As you could see, in an ecosystem, every organism depends on every other organism.

Water Ecosystem:

Water ecosystem is a system that is found in a water body. It could be better explained and understood using an example. Let’s take marine ecosystem as an example; 71% of our planet earth is covered by this ecosystem and 98% of our earth’s water is contained in this system. It is a home for many species which could range from small planktonic organisms to enormous mammals like sharks, and whales. Apart from those species, ocean is also home for variety of fishes. In a nutshell, all these species depend on aquatic ecosystem for their survival.

Unique qualities of marine ecosystem:

The dissolved salts in this ecosystem make it different from other aquatic ecosystems. There are various types of salts dissolved in the ocean such as Sodium (85%), and Chlorine. The salinity, amount of substances that are dissolved per kg, of sea water is known to be 35 parts per Kilogram of sea water. This salinity is known to change everyday among various marine ecosystems depending on different factors such as seasons, currents, and weather.

In certain areas,


varies due to outside influences such as tidal and freshwater from streams and rivers. Therefore, marine organisms are forced to adapt to changing salinity levels. However, some species are known to be intolerant to these changes in salinity, whereas some other organisms such as mussels, barnacles, and clams are adaptable to these kinds of changes.

Marine ecosystem and productivity:

Just like any other ecosystems, nutrients and light are main components to generate enough food and energy to sustain lives in marine ecosystems. However, these are the factors that limit the productivity in marine ecosystem.

Fresh water ecosystems:

These are considered to be the water systems that consist of drinkable water. Only 3% of our water supply is portable, and around 99% of it is frozen or concealed in aquifers such as wetlands, and ground water. The rest of it could be found in water systems such as lakes, rivers, and ponds. These fresh water sources are the main water suppliers for our industry, sanitation, agriculture, and as well as our drinking water resources.

These aquatic systems are home for more than 40% of our planet’s fish species.

Fresh water ecosystems’ threats:

Due to various human activities, most of world’s rivers, lakes, and other fresh water supplies are being affected every day.

Over 20% of known fresh water fishes are either extinct now or identified as endangered species in the recent years.

One of the main reasons why most of the fish species are facing extinction is because creation of dams and other water-diversion systems usually block the migration routes for fishes and disturbs there habitats.

Humans withdraw excess amount of water for various uses. As a result, fresh water species’ habitats either shrink or degrade.

Various wetlands around the globe are being drained for development purposes, which is also a reason for the depletion of fresh water resources.

In addition to the above factors, pollution is also one of the main reasons that threaten fresh water ecosystem.


  • Farming industry could be encouraged to reduce their use of pesticides through giving them incentives.
  • Establishing protected fresh water supplies such as wetlands.
  • Limit the dam constructions.
  • Regulate different water withdrawals.

Why should we preserve it?

We can not live without water, whether through direct consumption or indirectly through vegetables, meat juices or fruit. We could even live without food for several weeks but, we can not deprive us of water for more than three days. If we do then we would be endangering our health. The dieticians advice us to drink up to 1.5 to 2 liters of water a day to stay healthy.

If the population growth rate continues as it is now, by 2050 there will be 9.5 billion people on Earth and the population will stabilize around 11 billion people a century later.

In the West, each person consumes an average of between 50 and 100 liters of water per day, 50% more when you live in families with children. That is about 40 meter cube of water per year per person. Multiply that by several billion people with access to safe drinking water and you could calculate the amount of fresh water we need to live and grow. Double this number to know the amount of water we humans need in total. That’s about 20 times the capacity of Lake Nasser’s Aswan Dam, and half of the capacity of reservoir dam of Three Gorges!

Although water supplies are not available where people need it the most (the sources are generally in temperate latitudes while the biggest potential customers are located in the tropics), theoretically we have enough reservoirs of fresh water to meet those needs. But these reservoirs are being polluted or dried up. Considering the needs of the population and industries, the water will no doubt be one of the major challenges of the coming decades, “blue gold” of the XXI century.

If we do not protect the resource of human impact in the long run, we are endangering our survival by interfering with the natural cycle of water and aquatic ecosystems, the consequences could be irreparable. How can we act to preserve this resource?

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