Question

explain why water needs conservation even though large oceans surrounds the landmass

Answer 1

   Even though the Earth planet is covered by water (in the oceans) up to 75% or more, most of that water is not potable or fresh.  Only 2.5% of the water on the surface is potable or fresh. The water in the oceans is salty and is not drinkable directly.  Most of the water is dirty and contains a lot of different salts, that could be harmful to us.  The process of purifying water from the oceans and extracting drinking water is expensive and consumes energy.  Perhaps in future it will be feasible and cheap, we do not know yet.

   Also sources of pure ice and pure water are at the poles and on the mountain peaks. But there ar not many people living there. Using that water for the needs of all people living on Earth will damage the environment and ecosystem.

   In the lands we live in, we have some sources of water though water falls, rivers and streams, in addition to the rain water.  Year by year the population is growing at an alarming rate. So also the needs of water for drinking or for cleaning or manufacturing processes in industries.

   Further, the rainfall and distribution of water resources are not uniform around the Earth.  Hence, we need to conserve water very carefully.  Without sufficient water we cannot live at all.  If we use up all the ground water too quickly and waste it, then we will not have a lot of water for the future generations.  In order that our children, grand children and so on, live happily with sufficient water, we need to conserve.

Answer 2

Water constitutes more than 70% of the total earth surface.

Out of this only 2.7% is freshwater and is used by human beings for themselves for agriculture and for animal husbandry.

Marine water is not uniformly available over the different parts of the earth.

Moreover Terrestrial and freshwater forms cannot utilise saline water of oceans.