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8.3 ocean resources and currentsPresentation Transcript
Ocean Resources Mr. Silva Ag Earth Science
Fresh Water from the Ocean• Fresh water supplies are limited• Many developing countries lack a source of fresh water.• Distillation, is starting to increase. – Three methods: • Heating • Freezing • High pressure
Mineral from the Ocean• The ocean is a large source of minerals, its just very costly to harvest the minerals.• Each cubic kilometer= 6kg of gold• Nodules high in iron, copper, nickel, cobalt, phosphates.• Only grow 1-10 mm every million years!• Petroleum (oil)- limited supply and is being depleted faster than produced.
Food from the Ocean• Over half a billion people in the world lack protein in their diet.• Fish is a great source of protein.• Aquaculture (farming of the ocean), can solve many of those problems.• Problem is a lot of nutrients are on the bottom of the ocean.
Ocean-Water Pollution• Until recently, most waste was diluted, or destroyed as it spread throughout the ocean.• Increased about of – Lead – Insecticides – Plastic
Ocean Currents• A. Surface Currents Move in a Circular Motion!! – 1. Winds affect surface currents a. Wind provides energy to the water, causing movement b. Winds move along latitude lines in opposite directions • i. Tradewinds: Above & below the equator • Currents blow toward the equator line – Westerlies: In the middle latitude zones – Currents blow toward the poles
Ocean Currents• 2. Earth’s rotation affects surface currents – a. The Coriolis effect is the deflection of the earth’s winds and ocean currents caused by the earth’s rotation – b. The water flows in a circular motion • Northern Hemisphere: clockwise • Southern Hemisphere: counter-clockwise
Ocean Currents• B. Deep Ocean and Air Currents – 1. Currents move in a circular motion that is affected by temperature – 2. Temperature inversion: when warm temperatures are above the cooler temperatures either in the oceans or the atmosphere • Cold water (near the poles) sinks because it is more dense • Warm water (near the equator) rises because it is less dense
Ocean Currents3. Convection: the circular pattern made by water or air caused by the differential heating of earth a. Ocean water is heated unevenly due to the depth of the ocean and the heat energy from the sun – Pressure differences in the atmosphere (warm air is less dense, cold air is more dense) cause uneven heating and form convection cells around the earth• These patterns of circulation globally distribute the heat among ocean waters and the atmosphere