08 - 1 These are Changing Times for Earth’s Ocean…...

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Unformatted text preview: 1 These are Changing Times for Earth’s Ocean… Earth image by Apollo 17 Dec.7, 1972 • Chemical and Solid Water Pollution • Unsustainable Depletion of Biological Resources • Coastal Overdevelopment • CO 2 Emissions • Overpopulation The Bad News for Today’s Ocean… Guest lectures: • PhD student Ruben van Hooidonk – coral bleaching • Dr. Jim Ogg – overfishing • Dr. Marisol Sepulveda – toxins in fish Coral bleaching: expulsion by the corals of the single-celled algae (zooxanthellae) which normally live in their tissues, and on which they depend as a major food source. Increasing cases of widespread bleaching may be a consequence of global warming. Guest lectures: • PhD student Ruben van Hooidonk – coral bleaching • Dr. Jim Ogg – overfishing • Dr. Marisol Sepulveda – toxins in fish A century of dramatic decline in the fisheries (left) and commercial slaughter of the five largest whale species, 1940–85 (below). Unsustainable Depletion of Marine Biological Resources 2 Guest lectures: • PhD student Ruben van Hooidonk – coral bleaching • Dr. Jim Ogg – overfishing • Dr. Marisol Sepulveda – toxins in fish Effects of contaminants on aquatic organisms Inadvertent experimentation • Our species has always exercised its capacity to consume resources and pollute its surroundings, but only in the last few generations have our efforts affected the ocean and atmosphere on a planetary scale. • The introduction into the biosphere of unnatural compounds (or natural compounds in unnatural quantities) has had, and will continue to have, unexpected detrimental effects. • The destruction of marine habitats and the uncontrolled harvesting of the ocean's living resources have also disturbed delicate ecological balances. • We have embarked on a time of inadvertent global experimentation and find ourselves in difficult situations for which solutions do not come easily. Demands for the ocean’s recreational space, physical, and biological resources are increasing. Can growth continue at this rate? Water pollutants Characteristics of a pollutant? – Quantity - the amount of a particular pollutant present – Toxicity - the amount of a pollutant required to cause damage – Persistence - the length of time a pollutant lasts in an environment Fig. 18-1, p. 507 3 Sources of water pollution? • Toxins that come from industrial and municipal wastewaters , runoff from farms and urban areas , and the erosion of soils . – These toxins can include naturally-occurring chemicals that are present in higher concentrations because of human activities as well as new, man-made compounds such as DDT. • biostimulants from sewage and industrial wastes • oil from runoffs, accidental spills, and oil and gas production • sediments from erosion caused by farming, forestry, mining, and development • plastics and other debris from ships, fishing nets, and containers • thermal pollution from the cooling water that comes from power and industrial plants...
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08 - 1 These are Changing Times for Earth’s Ocean…...

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