1. Acid rain and pollution

2. Acid rain Rain is naturally acidic (pH 5.6) because it mixes with CO 2 making water acidic Rain is naturally acidic (pH 5.6) because it mixes with CO 2 making water acidic Precipitation with pH lower than 5.6 is acid rain Precipitation with pH lower than 5.6 is acid rain Aquatic life prefer pH 6-8- excessive amounts of acid rain leads to trouble with reproduction and lack of plant growth Aquatic life prefer pH 6-8- excessive amounts of acid rain leads to trouble with reproduction and lack of plant growth Acid rain dissolves calcium, eventually leading to snail-eating birds having eggs with thinner shells Acid rain dissolves calcium, eventually leading to snail-eating birds having eggs with thinner shells

3. Causes of Acid rain SO 2, SO 3, NO, NO 2 - created by industrial process and fuel combustion SO 2, SO 3, NO, NO 2 - created by industrial process and fuel combustion –Aside from acid rain, these compounds cause airway constriction Once these compounds mix with oxygen- containing compounds, form sulfuric and nitric acids Once these compounds mix with oxygen- containing compounds, form sulfuric and nitric acids These acids fall with precipitation- both are strong acids These acids fall with precipitation- both are strong acids

4. What can be done about acid rain? catalytic converters in cars- converts nitrogen oxide to N 2 and O 2 to be emitted catalytic converters in cars- converts nitrogen oxide to N 2 and O 2 to be emitted Scrubbing- exposing sulfur dioxide to lime solution to form calcium sulfite- non-toxic, but is disposed of in a landfill Scrubbing- exposing sulfur dioxide to lime solution to form calcium sulfite- non-toxic, but is disposed of in a landfill Draw your version of the picture on page 439 (about how acid rain forms) Draw your version of the picture on page 439 (about how acid rain forms)

5. Oceans How they were formed How they were formed –Hot planet cooled down In cooling process, water vapor released, then condensed to form bodies of water In cooling process, water vapor released, then condensed to form bodies of water –Amount of water the same as the age of the dinosaurs –Hydrosphere- water layer of Earth- 97% of water in form of oceans –Lithosphere is solid layer that covers Earth –Oceans fed by rivers, groundwater, rain,

6. Sources of salt Weathering of rocks on land Weathering of rocks on land –Contribute silica, sodium, calcium, potassium, and magnesium ions –Bicarbonate (HCO 3 ) added by rivers from dissolved limestone Chemical reactions b/t seawater and volcanic eruptions on ocean floor Chemical reactions b/t seawater and volcanic eruptions on ocean floor Volcanic eruptions on land Volcanic eruptions on land

7. Composition of seawater 99% ions- Cl, Na, SO 4, Mg, Ca, K and more than 70 small amounts of trace elements (like iron) 99% ions- Cl, Na, SO 4, Mg, Ca, K and more than 70 small amounts of trace elements (like iron) Salinity- refers to amount of salt dissolved in 1kg of water Salinity- refers to amount of salt dissolved in 1kg of water Misc. components of seawater: Misc. components of seawater: –Organic materials from living organisms –Dissolved gases (N 2, O 2, CO 2, H 2, and others Salinity constant over the years b/c of balance Salinity constant over the years b/c of balance –Ex: rivers provide salts and minerals, organisms use ions to build shells and skeletons, excess substances deposit on rocks, etc.

8. Excess of carbon dioxide revisited Photosynthesis and respiration of organisms release oxygen and carbon dioxide in the water- normal Photosynthesis and respiration of organisms release oxygen and carbon dioxide in the water- normal Excess Carbon dioxide- would make pH lower, but calcium carbonate buffer neutralizes it to keep pH about 8- but what if buffer fails? Excess Carbon dioxide- would make pH lower, but calcium carbonate buffer neutralizes it to keep pH about 8- but what if buffer fails?

9. Pollution and ocean food chain Pollution enters oceans via dumping and flow from rivers and streams Pollution enters oceans via dumping and flow from rivers and streams –Raw sewage, toxic chemicals, heavy metals, petroleum –Once enter ocean- diffuses Pollutants are passed through the food chain and concentrate in tissues of marine organisms Pollutants are passed through the food chain and concentrate in tissues of marine organisms

10. Pollution passed up the food chain food chainfood chain Producers absorb pollutants in process of making energy Producers absorb pollutants in process of making energy Herbivores eat producers, and acquire energy and pollutants absorb in fatty tissue Herbivores eat producers, and acquire energy and pollutants absorb in fatty tissue Carnivores eat herbivores, acquire energy and higher concentrations of pollutants Carnivores eat herbivores, acquire energy and higher concentrations of pollutants –Toxins can sometimes be passed along to young