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Unit 6 Human Impact What we do to the oceans. Human Impact • Pollution – anything introduced into the environment by humans that is harmful oChemicals, trash, noise, heat, sewage, etc. o Biodegradable – can be broken down by bacteria. (paper) o Nonbiodegradable – can not be broken down by bacteria (plastic) Where does the pollution come from? • Most of the pollution (75%) come from human activities • How do marine species handle pollutants? o Depends on • Its sensitivity • Toxicity of pollutants oPersistence – how long it remains in the remains in the environment Pollutants Oil • Natural leaks only account for 10% of the 6 million metric tons that enter into the ocean Effects of Oil on Marine Life • Can be ingested through food o Interferes with reproduction, development, and growth o Young are most affected • Birds and Mammals o Can get trapped in fur or feathers o Inhibits ability to stay warm or to fly Oil spill clean up • worst oil spills • Fencing Off o Use fire-retardant booms to contain oil • Skimmers o Scrape oil off of surface of water • Dispersants o Chemicals that break oil into small droplets o Dispersants can be toxic • Hot or Cold Water Washing o To remove oil from shorelines o Can be harmful to microorganisms • Bioremediation o Use of engineered bacteria to detect and break down oil Heavy Metals • High molecular weight elements that can cause damage to organisms in small concentrations o Interfers with a cells normal metabolism o Found in industrial waste, land fills, gasoline o Human activities release 5X more than natural soruces • Examples: oMercury, Cadmium, Nickel, Lead, Zinc, Copper, Chromium Mercury • Sources: incineration of mercury containing waste (hospital waste, mercury lamps, metal recycling smelters, coal power plants (#1)), dental wastewater (fillings), Caribbean folk medicine, gold mining http://www.chicagotribune.com/news/chi-mercury-htmlpage,0,6027124.htmlpage • Most harmful when in form of methyl mercury (converted by bacteria) [CH3Hg]+ • Can accumulate in seafood • Causes brain, kidney, and liver damage and birth defects in people Pesticides • Enter oceans: wind, runoff o Farmers spray crops o It can blow in o It can be washed in by rain • Created to kill life • Can affect reproduction and growth of marine organisms • Biological amplification occurs with pesticides too DDT: dichloro-diphenyl-trichloroethane • • • • Pesticide to kill mosquitoes Killed many birds and fish Is currently banned in the US Used in third world countries where diseases like malaria are prevalent • Solid Waste o we generate over 1100 million metric tons of solid waste a year per person! • Plastic – 10% o Basically doesn’t degrade for 1000s of years or never! What is the solution to all this solid waste? • Sediment o Runoff from mining, farming, forestry o Destroys coastal ecosystems (marshes) o Kill reefs • Sewage o Treated sewage water o Contributes to eutrophication Biological Amplification • Persistent chemicals do not break down • Organisms absorb or digest pollutants • Pollutants accumulate in top predators • Phytoplankton absorb mercury • Shrimp eat thousands of phytoplankton • Small fish eats hundreds of these shrimp • Large tuna eats thousands of these fish • This is why pregnant women shouldn’t eat too much fish Alien Species • Any species that is not native to the environment • Harmful for several reasons: o May carry parasites o No natural predator o Compete with natives for resources • Enter other oceans through ballast water o (Water holds in cargo ships) Endangered Species • Extinction of marine animals can be caused by oOverfishing/overhunting oHabitat destruction oPollution oCompetition with alien species Whaling: Hunting of Whales • Led to all whales being endangered • 1994 many countries banned whaling in Antarctica o Except: Norway and Japan • Started hunting dolphins instead The costs of pollution Habitat Destruction • Estuaries o Dredged for ships o Filled in for building on o 1/3 of estuaries have disappeared in the US • Mangroves o Similar to estuaries o Also cut for timber and fuel • Coral Reefs o Clearing of rainforests: causes soil to wash into the water o Explosives for hunting fish o Bleaching Global Changes • Ozone depletion o UV damages DNA • Climate change o Increase in ocean temperatures • Harms sea life • Increases sea levels • Changes in weather patterns • Changes in ocean currents What can be done? • • • • • • Slow population growth Cut down on consumption Be careful what you buy Conservation Reduce your waste recycle