Ocean Properties and Chemistry. Ocean Properties.
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Transcript of Ocean Properties and Chemistry. Ocean Properties.
Ocean Properties and Chemistry
Ocean Properties
Physical Properties of Water
• Importance of water: We are made of 70% of water and some ocean organisms are made up to 90% water
• Polar• Excellent solvent• Hydrogen bonds
(makes water sticky= cohesion, keeps water stable at different temps.
• Specific heat (ability to hold onto heat)
• Ability of light to penetrate water
Ability of light to penetrate water
150 meters
150 meters
900 meters
900 meters
1000 meters or more
1000 meters or more
Chemical Properties of Water
• Acidity and alkalinity• pH scale– 0-7 acidic– 7 neutral– 7-14 alkaline
• Seawater is slightly alkaline between 8.0-8.6 on average– Acid:_amount of hydrogen ions H+– Base:_amount of hydroxide ions OH-
More Chemistry
Importance of pH in the oceans• When carbon dioxide (CO2) is absorbed by
seawater, chemical reactions occur that reduce seawater pH, and saturation states of biologically important calcium carbonate minerals
No calcium Carbonate, No shells
• Projected sea water in 2100 will dissolve the shells of all sea life
Gases in Seawater
• Gases from biological processes– Photosynthesis________– Cellular respiration______– Decomposition________
• Oxygen-minimum zone• Solubility of gases in seawater• Environmental variables affect amount
of gases:__________
Oxygen Levels In the ocean 700 m -1200 m OMZ
Composition of Seawater• Ionic salts– Sodium (Na+)– Magnesium (Mg2+)– Calcium (Ca2+)– Potassium (K+)– Chloride (Cl-)– Sulfate (SO4
2-)
• Trace elements
Salinity
Salinity: How much salt is dissolved in water, it is measured in ppt (parts per thousand) oceans are around 30 ppt
• 3.5% salt and 96.5% water by mass
Salinity• Salinity changes due to:• evaporation: high salinity • precipitation and runoff: low salinity
Salinity in Bays and Estuaries• Less than 25 ppt is called brackish, meaning a
combination of salt water and fresh water. • Bays and Estuaries have Brackish water
Tides (Changes Salinity)• Low Tide: Low
salinity• High Tide: Normal
Salinity• (Bays Estuaries)
Physical Properties of Water1. List 5 physical properties of ocean water2. What is Salinity? Where does it change in the
oceans?3. How does the oxygen content change in the
ocean?4. What is the difference between an acid and a
base?5. Describe how light travels in water.6. Give an example of a polar molecule and how it
dissolves other polar substances.