Did You Know? Because the architecture and chemistry of coral is so similar to human bone, coral has been used to replace bone grafts in helping human bone to heal quickly and cleanly.

Did You Know? Antarctica has as much ice as the Atlantic Ocean has water. Each year, three times as much rubbish is dumped into the world's oceans as the weight of fish caught

Chapter 8 Questions ISN pg. 37 Text Pg. 8-9 Complete study questions 1-9 Text pg. 8-22 read Ocean Acidification and answer the following questions: 1. Based on the reading, what is the major concern of scientists in recent years regarding ocean acidification? 2. What evidence are they using to validate these concerns? TODAY is your only day in class to work on these!

Goal: Explain water’s chemical bonds. Notes: ISN 23 Seawater Goal: Explain water’s chemical bonds. Notes: ISN 23

The Water Budget Evaporation Condensation Precipitation Transpiration Ocean- 97% of all water on Earth Determines Sea Level Has changed in the last 12,000 years (last Ice Age)

Covalent Bond between oxygen and hydrogen The hydrogen and oxygen are held together by sharing electrons. This is called a covalent bond.

Polar (dipolar) molecule The hydrogen end has a positive charge and the oxygen end has a negative charge. This allows water to bond with other water molecules via hydrogen bonds

HYDROGEN BONDS The negative oxygen side of a water molecule is attracted to the positive hydrogen side of another molecule. This holds water together.

STRENGTH OF HYDROGEN BONDS The hydrogen bonds joining water molecules are weak, about 1/20th as strong as covalent bonds. They form, break, and reform with great frequency

STRENGTH OF HYDROGEN BONDS Extraordinary Properties that are a result of hydrogen bonds. Liquid at room temperature because H bonds hold molecules together, causing more energy to turn to gas. Cohesive behavior – water molecules stick to one another. Adhesive – water molecules stick to other materials. Viscous – water has a higher viscosity (tendency to resist flow) because the H bonds hold molecules together Surface tension – a skin-like surface which resists objects attempting to penetrate its surface. Ice floats – as water cools, it takes a crystal structure, taking up more space than liquid (less dense). If ice didn’t float, Earth’s climate might be too cold for life.

strong, flexible “skin” over water surface caused by cohesion Surface tension – water’s resistance to objects attempting to penetrate its surface. strong, flexible “skin” over water surface caused by cohesion What would happen if soap was added the this water The soap would break the bonds that cause surface tension & the insect would fall in the water

Viscosity

Specific Heat is the amount of heat that must be absorbed or lost for one gram of a substance to change its temperature by 1oC. Three-fourths of the earth is covered by water. The water serves as a large heat sink responsible for: Prevention of temperature fluctuations that are outside the range suitable for life. Coastal areas having a mild climate A stable marine environment

Solutions and Mixtures in Water Solution – molecules of one substance are evenly dispersed among the molecules of another substance. Water is the solvent the solute is the substance being dissolved. WATER IS THE UNIVERSAL SOLVENT (many substances can dissolve into water)

Solutions and Mixtures in Water There are two types of mixtures 1. Homogeneous – uniform in appearance. 2. Heterogenous – is not uniform and consists of visibly different substance. Seawater is a homogeneous solution because water’s polar molecules pull apart the salt (NaCl), causing them to become ions (charged particles). This keeps the salt in solution.

What is salinity? Salinity is the total concentration of all dissolved inorganic solids. The major sea salts are NaCl (sodium chloride) and other salts including KCl (potassium chloride).

Salinity Measured in parts per thousand (º/oo) Seawater ~35º/oo How do you figure out the percent of salt? Divide ppt by 10 & you get the percent. Soooo…. What is the percent salt of ocean water on average? 3.5%

What is the composition of ocean water? Water (Solvent) (96.5%) + Dissolved substances (Solute)(3.5%) = Product (Solution) NaCl is Sodium Chloride= Salt Dipolar water dissociates easily and is Attracted to the positive & negative charge of H2O

Salinity of Water Brackish water results when fresh water mixes with seawater in estuaries. Brine water is saturated with dissolved salts in areas with high evaporation and little inflow of fresh water. Salinity is determined by scientists by using a salinometer which determines the electrical conductivity of water.

Colligative Properties of Seawater Colligative properties – properties of a liquid that may be altered by the presence of a solute Raised boiling point and decreased freezing temperature Ability to create osmotic pressure Electrically conductive Decreased heat capacity Slowed evaporation

What factors affect seawater’s pH? Pure water has a pH of 7. Seawater has a pH of 7.8 to 8.3 (mildly alkaline). pH scale ranges from 1-14. A pH of <7 is acidic, 7 is neutral, and >7 is basic (alkaline).

Carbon cycle and pH of ocean The upper sunlit depths (photic zone) usually have a higher pH because photosynthetic organisms use the carbon dioxide which makes ocean water more acidic.

Photic zone Depths determined by how rapidly seawater absorbs light & converts it to heat energy Influences Dissolved substances Suspended sediments Plankton population

Factors Affecting Water Density Turbidity: measure of how cloudy water is. As turbidity increases, density also increases. Salinity increase or Temp decrease =Density increase

What is the pycnocline? The thermocline and halocline together make a zone in which density increases with increasing depth.

Buoyancy Buoyancy - the upward force on an object in a fluid that is equal to the weight of the displaced fluid.

Pressure 1 atmosphere (atm) at sea level Increase 1 atm for every 10 meters increase in depth Solubility of dissolved gases increases w/ decreased temperature Nitrogen Carbon dioxide Oxygen

http://www. youtube. com/watch http://www.youtube.com/watch?v=0B0EhuxJsts&safety_mode=true&persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=cEnJITnn_4U&safety_mode=true&persist_safety_mode=1&safe=active

What is the difference between osmosis and diffusion? Diffusion – movement from high concentration to low concentration. Heat speeds up diffusion. Osmosis – diffusion through a semipermeable cell membrane. Water moves through the cell from high concentration of water to lower concentration of water.

Osmosis & Diffusion Diffusion Osmosis Write the definitions. http://www.youtube.com/watch?v=STLAJH7_zkY&feature=related&safety_mode=true&persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=6Rd2bEp380w&feature=related&safety_mode=true&persist_safety_mode=1&safe=active Osmosis Write the definitions.

What types of solutions Are these? Watch the clip and think salinity instead of tonicity. Hypotonic Isotonic Hypertonic http://www.youtube.com/watch?v=6MWl3DCa2uM&safe=active

Osmoregulators – organisms with the ability to adapt to sur- rounding salinity changes

Active Transport vs. Passive Transport. Passive transport does not require energy (example: osmosis) Which requires energy? Active Osmoregulators would use which of the following? Active transport

Osmoconformers Osmoconformers cannot control their internal water concentration. Their internal salinity rises and falls along with the surrounding seawater’s salinity.