1. Chemical Oceanography
Objectives:
Define salinity, dissolved oxygen, and temperature, and their influence on marine life.
Discuss chemical properties of ocean water and their influence on marine life.

2. Where do the ions in seawater come from?
Weather of rocks
Carried to the sea by rivers
Sodium, Potassium, Magnesium
Hydrothermal vents and volcanoes (to rain)
Chloride, Sulfide

3. Composition of Seawater
96.5 % hydrogen and oxygen (H2O)
Solids dissolved in seawater
85% = chlorine, sodium
magnesium, sulfur, calcium, potassium, carbon, silicon, and nitrogen
Ca and Mg carbonates are used by organisms to build shells, bones, and coral skeletons

4. Salinity – the total amount of dissolved salts in the water
Average salinity of the ocean is between 33 and 35 parts per thousand (ppt)
Ppt = parts per thousand = # of grams of salt left if 1,000 water is evaporated
2. Salinity and temperature determine the density of seawater
Increase in salinity - increase in density
Decrease in temperature - increase in density

5. Salinity – cont.
Salinity and temperature help form currents called thermohaline circulation
bring up nutrient- rich, deep water to the surface

6. Dissolved Oxygen Sources: Adaptations to get oxygen: Phytoplankton
O2 diffuses into the atmosphere from the ocean
Adaptations to get oxygen:
gills are respiratory surfaces that have evolved large surface areas to maximize diffusion

7. Application to Ecosystems
Estuaries
Salinity highest at the mouth of stream or river
Higher the salinity, less dissolved oxygen
Extremes
Red Sea > 40 ppt (very productive)
Dead Sea >300 ppt (bacteria)
Great Salt Lake ppt (brine shrimp

8. Transparency Allows sunlight to penetrate
Sunlight contains all colors of the visible spectrum
Not all penetrate seawater equally well
Most transparent to blue light

9. Application to deep sea
After m
A “blue world” due to absorption
Animals are adapted to see blue not reds
Dragon Fish
Illuminate red light, other fish won’t see it

10. Temperature ocean temperature ranges from 28F to 86F
Heat from the sun drives winds, that control ocean surface currents
Currents affects the distribution of marine organisms