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.

Earth Science: THE MOVEMENT OF OCEAN WATERS

1. WAVES

• The highest point of a wave is the CREST, and the lower point, the TROUGH.

• The length of a wave is the distance from one crest to the next crest, or from one trough to the next trough.

• The stronger the winds blow, the bigger the waves formed

• In open ocean, the longer distance the waves travel, the higher and longer they become.

• A Mass or rocks and soil that slides into thw ater from the edge of land disturbs the water and forms waves. This is a LANDSLIDE into the sea.

• The larger the mass of the rocks hitting the water, the larger the waves formed.

• In May 1960, giant waves from the Pacific Ocean hit the shores of Polollo Island off Quezon province. In August, 1976 giant waves destroyed the coastal towns of Cotabato and Davao. Undersea earthquakes were reported as the cause in both events.

• TSUNAMI refers to the giant waves formed by undersea earthquakes, volcanic eruptions and landslide.

• Tsunami are about 150 km long, traveling at about 800 km/h. They increase in height while traveling, rising as high as 30 m as they approach shore.

2. OCEAN SURFACE CURRENTS

• Flowing water carries floating objects away. The flow of the surface water of seas and oceans is known as surface currents. Surface currents mix and redistribute water in the oceans.

• Records of sailing ships and data from observations made by oceanographers show that ocean surface waters flow in large circulating currents. These circulating currents maintain their directions.

• Surface currents are driven mainly by winds. The easterly winds pushing surface water toward the equator form the equatorial currents.

• The presence of land in the path of the equatorial currents turn them to the right in the northern hemisphere and to the left in the southern hemisphere. Beyond the 30 N ans S latitudes the westerly winds push the currents. The turning to the right in the northern hemisphere and to the left in the southern hemisphere is called the Coriolis effect which is caused by the earth's rotation.

• The Gulf Stream of the North Atlantic Circulation is the fastest and strongest of the major currents. Part of the Benguela Current from the South Atlantic Circulation joins the Gulf stream and adds to its volume and speed.

• The current in the Indian Ocean is the only one which changes direction with the monsoon seasons. When the southwest monsoon wind blows, the Indian Ocean Current flows eastwest monsoon wind blows, the Indian Ocean season Current flows eastward. When the northern monsoon wind blows, the current flows westward.

• The Antarctic Circumpolar Current flows in a west to east direction around the Antarctic Continent. There are no land masses block and turn it. Being driven by winds coming from the west, it is also called the West Wind Drift.

• In the middle of each circulation is calm water. The best known of them is the Sargasso Sea in the North Atlantic Circulation. The name Sargasso is taken from the brown seaweed Sargassum growing abundantly in its calm water. Once caught there, they had to wait long for strong winds to push their sails and get them out.

• Surface currents are still useful today in water transportation. Although modern ships run on fuel, they move faster on less fuel by following the currents.

3. DENSITY CURRENTS (to be continued)