Final Notes from Lecture - Environmental Issues I. II. III....

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Environmental Issues I. Contaminants a. 50% or more of marine litter is in some form of plastic b. 135,000 tons of plastic trash are dumped into the ocean c. 149,000 tons of fishing gear are lost or discarded in the ocean d. 7,000,000 tons of trash are added to the ocean II. Plastics a. Their lightweight is deadly to the marine environment b/c they can float on the surface of the ocean or within the water column b. Composed of long chains of hydrocarbons (hydrogen and carbon atoms that are bound together tightly) c. Micro-organisms such as plankton (tiny plants and animals that live in the water) do not have the ability to break down these bonds d. Plastics do not decompose easily III. Other Forms of Marine Pollutants a. Toxicants – PCBs, pesticides, heavy metals (nickel, lead, zinc, chromium, copper, cadmium, silver) b. Nutrients – Inorganic (phosphorous, nitrogen, sulfates, “Plant Food”) and organic (sewage sludge, “Bacteria and archaea food”) IV. Pollution in Rivers a. Cuyahoga River in Ohio i. Caught on fire several times between 1936 and 1969 ii. Debris and oil concentrated on the water’s surface were ignited V. Pollution from sewage disposal a. Sewage Effluent i. Before 1972, U.S. law allowed discharge of anything into a body of water until it was “polluted” ii. Federal Clean Water Act – effort to make U.S. water “fishable and swimmable”; mandated the upgrade of sewage treatment to secondary level by 1977 b. Modern Urban Sewer Systems i. Primary screening ii. Primary clarifiers iii. Aeration tank iv. Final clarifier: chlorination VI. Pollution by toxicants a. Polychlorinated Biphenyls (PCBs) i. Insoluble by water ii. Don’t burn except at high temperatures iii. Don’t conduct electricity
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iv. Do not degrade during use v. Conduct heat very well vi. Excellent candidates for a variety of uses in electric power equipment, electronics, the printing industry, and elsewhere b. Dichlor-diphenyl-trichlorethylene (DDT) i. Pesticide used on crops to kill mosquitoes ii. Use of DDT was banned in the US at the end of 1972 iii. White, crystalline, powder with little odor iv. Low solubility in water v. Relatively high solubility in fats VII. Eutrophication a. Problem of over dose of nutrients to living organisms b. Will increase productivity, sedimentation of organic matter, bacterial respirations, reduction of dissolved oxygen c. Overabundance of carbon and lack of oxygen d. Pycnocline – rapid change in density with depth e. Inorganic nutrients (N, P, S) are added to the system f. Phytoplankton increases in number g. Zooplankton feed of the algae, increase in number, and respire h. Zooplankton die and sink to the bottom i. Bacteria decompose the zooplankton and use up oxygen j. Hypoxic and anoxic conditions are produced VIII. The Carbon Cycle a. Photosynthesis – CO2 + H2O CH2O + O2 b. Respiration – CH2O + O2 CO2 + H2O c. Biological Pump – the sum of suite of biologically-mediated procceses that transport carbon (CO2) from the surface
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This note was uploaded on 09/21/2011 for the course MARS 1020 taught by Professor Binder during the Fall '08 term at University of Georgia Athens.

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Final Notes from Lecture - Environmental Issues I. II. III....

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