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The ocean wildlife …. What is there in that vast ocean? By Rachel Kent and Cameron Gonet Life in the Oceans Objectives Ocean Chemistry and Marine Life Sunlight and Marine Life Ocean Environments Life in the Oceans
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The ocean wildlife…. What is there in that vast ocean? By Rachel Kent and Cameron Gonet
Life in the Oceans Objectives • Ocean Chemistry and Marine Life • Sunlight and Marine Life • Ocean Environments
Life in the Oceans • From fossils we know that life started in the oceans more than 3 billion years ago • Marine organisms have changed to match the changes in the physical and chemical properties of the oceans • Most marine organism depend on two major factors for their survival; • Essential nutrients available in seawater • Sunlight
Ocean Chemistry and Marine Life • Marine plants and animals take nutrients and dissolved gasses from the water and return other nutrients and gasses • Nearly all ocean life is regulated by the life processes of plants, the oceans’ primary producers • Plants absorbed carbon, hydrogen, oxygen and sulfur, but there is too much of these substances for plants to diminish • They also absorb nitrogen, phosphorus and silicon which are far less abundant • Areas that are depleted of nutrients are barren of plants
Ocean Chemistry (continued) • Organism absorb nutrients and store them in their tissues. When the die, bacteria breakdown tissues and the nutrients return to the water • Nutrients are pulled by gravity away from the surface to the bottom where nutrients concentrations are highest • For the nutrients to be used to support life in the sunlit zone again, the nutrients have to be transported to the surface • Transport occurs two ways: • Upwelling occurs when surface water is blown offshore and is replaced by deeper water • Wave and tide action cause deep water to mix with surface water
Sunlight and Marine Life • All plants and many microscopic organisms require sunlight, so plant growth is restricted to the upper 100 meters of the ocean • Deeper than 100 M there is not enough light to sustain photosynthesis • Where there is enough light there is usually an abundance of two types of plankton: • Phytoplankton (plants) which use photosynthesis for energy • Zooplankton (animals) which feed upon phytoplankton
Sunlight (continued) • Plankton are eaten by nekton, which are organisms that can swim and hunt for food • Fish, squid dolphins are all nekton • Plankton are consumed primarily by small fish and squid which are, in turn, eaten by larger animals: • Organisms that live on the bottom are called benthos • Sea anemones, corals, crabs and oysters are all benthos
Organisms Plankton Phytoplankton Zooplankton Nekton Larval Fish Humpback Whale
NOT IN THE BOOK • Until the discovery of deep, geothermal vents off the Galapagos Islands, it was thought that all life on earth depended on energy derived from the sun through photosynthesis • The discovery of “chemoautotrophic organisms” living on chemical energy coming from the vents changed that theory
Ocean Environments • Two general environments in the ocean • Benthic or bottom • Intertidal zone: shallowest with most light • Sublittoral Zone: shallow, always submerged • Bathyal Zone: Begins at Continental Slope to 4,000 M • Abyssal Zone: No light, 4,000 to 6000 M • Hadal Zone: Deeper than 6,000 M, confined to Ocean trenches • Pelagic or water • Neritic Zone: Water column above the Continental Shelf, with abundant sunlight and moderate temperatures • Oceanic Zone: Extends into the deep and open ocean waters beyond the Continental Shelf • Epipelagic Zone, Mesopelagic Zone, Bathypelagic Zone and Abyssolpelagic Zone
Chapter 21.3 Section Objectives ~Describe three important resources of the ocean. ~Explain the threat to ocean life posed by water pollution
Vocabulary Words • Distillation~~ Extraction of salt in salt water by boiling it. • Aquaculture~~ The farming of the ocean; Developing and raising special breeds of marine animals and plants that yield large amounts of food.
Fresh Water from the Ocean ~Throughout the world the need for fresh water is increasing rapidly. ~The increasing demand for water can be met in two ways. First, the fresh water now available can be conserved to avoid waste. Second, the amount of available fresh water can be increased. The water supply can be increased by finding ways to convert ocean water to fresh water.
Continued… ~Distillation is one means of getting fresh water from the ocean, which involves boiling the water. Heat causes the liquid water to evaporate, leaving dissolved salts behind. However, evaporating liquid involves a great deal of heat and consistency of heat. ~Another method of desalinating ocean water involves freezing the water. When water freezes, the first ice crystals that form are free of salt. The salt remains in pockets of liquid water in the ice. The ice can be removed and melted to obtain fresh water.
Food from the Ocean ~Of all the resources that the ocean is capable of supplying, the one in greatest demand is protein-rich food. At this time a large part of the population of the world has a starchy diet. Such a diet can maintain life, but the lack of protein to build strong tissues decreases the ability of a person’s body to fight disease. Perhaps half a billion people in the world suffer from some form of disease caused by a lack of protein in their diet. ~In the future aquaculture, the farming of the ocean, will become an important part source of food production. Aquaculture involves developing and raising special breeds of marine animals and plants that yield large amounts of food. Aquaculture has already been used to successfully grow catfish, salmon, oysters, and shrimp on large aquatic farms.
Ocean-Water Pollution ~The oceans have been used as a dumping ground for many kinds of wastes, including garbage, sewage, and nuclear wastes. Until recently, most wastes were diluted, or destroyed as they spread throughout the ocean. But the growth of the world population and the increased use of more toxic substances have changed the situation. The ability of the ocean to absorb waists and renew its self cannot match the increasing amount of waste that is being produced worldwide.
Continued… ~Productive coastal waters are in the greatest danger. Pollution has destroyed clam and oyster beds in some local areas. Sea birds have been found tangled in plastic products. Beaches have been closed because of sewage, medical wastes, and oil washed onto the sand.