THE WATERS OF THE EARTH

INLAND WATERS

· Inland bodies of water are mainly streams, lakes, and ground water.

· A stream is consists of running water in a naturally formed channel which begins in elevated area and usually ends in the sea or lake.

· Rivers are permanently streams with flowing water throughout the year.

· Brooks, creeks, and rivulets are smaller channels of running water which may or may not be permanent.

· A stream on a steep slope with fast flowing water forms a rapid.

· A stream dropping over a precipice or the vertical side of a mountain forms a waterfall.

· The Philippines has over 700 principal rivers.

· Cagayan River in Northeastern Luzon is the longest and largest.

· Lakes are large bodies of standing held in deepened areas of land called basins.

· Ponds are much smaller and shallower bodies of standing water than lakes.

· Swamps are generally wider than ponds or lakes but are shallower because of sediment deposited at the bottom. Swamps are usually overgrown with vegetation.

THE DISSOLVED SUBSTANCES IN INLAND WATER

· The most important gases dissolved in water are oxygen and carbon dioxide.

· Oxygen is needed for the respiration of aquatic animals.

· The maximum concentration of dissolved oxygen in water decreases as the temperature of water increases.

· At the same temperature, more oxygen dissolves in inland fresh water than in sea or ocean water due to high salinity in sea or ocean water.

· Pollution affects the dissolved oxygen in water. Bacteria in the water break down the pollutants into simpler and not harmful substances. The process uses dissolved oxygen. Large amounts of pollutants remove large amounts of dissolved oxygen.

· Dissolved carbon dioxide in water is used by aquatic plants, mostly microscopic organisms known as plankton, in photosynthesis. Photosynthesis occurs in sunlight. The carbon dioxide concentration of water, therefore, decreases in daylight and increases at night.

· Some amount of carbon dioxide combines with water to form carbonic acid. Carbonic acid can dissolve calcium carbonate in seashells. Given time, the shells of dead animals of can be dissolved by carbonic acid and be made available for further shell formation of aquatic animals.

· Hydrogen sulfide, methane, free ammonia, nitrogen and few other gases also dissolve in inland waters. Most of them are dissolved from the atmosphere. Hydrogen sulfide and methane are also produced when decomposition caused by bacteria takes place in water.

· In sea water, the most abundant dissolved solid is sodium chloride. In fresh water, calcium and magnesium are generally more abundant. Calcium is needed by aquatic animals for shell formation. Magnesium is used by plants in the formation of chlorophyll, a substance needed for photosynthesis.

CARE OF THE EARTH’S WATERS

· Good quality water in lakes and rivers as well as in seas and oceans encourages an abundance of fish and other living things to bred and thrive in them.

· Good quality inland waters are also source of water supply for drinking, cooking, cleansing, and other domestic uses.

· Many modern activities lead to the destruction of water areas. Boats and ships leak oil into the water. Sea oil exploration and extraction destroy the breeding places of fish and seashells and pollute and industrial chemicals run off into water bodies and seep into ground water reservoirs to pollute them. Mining destroys ground water deposits. Industrial plants, mines and cities should remove pollutants from waste water before draining it into rivers and lakes.

· Excessive use of water can be avoided in many little ways at home. Never leave tap water running while you soap and rub your hands or brush your teeth. Open it only when you are ready to use water. Reuse water whenever possible. Wash water used in washing clothes can be reused for cleaning floors and toilets. Take care not to pollute bodies of water. Rivers and lakes should not be used as garbage and waste water dumps.

· Treated sewage and waste-water released into rivers, lakes, and seas are less damaging than the untreated. Forests hold water longer in the ground. Prevent flooding in the surrounding lower areas, and supply water during the dry months. The denudations of forests reverse these effects. During the rainy months, water can be collected in man-made dams and reservoirs.