1. Chapter 6 and 7 Marine biology Michael Slemp

2. Polar bear Ursus Maritimus  Native largely within the Arctic circle  Largest land carnivore (eats meat)  Largest bear (together with Kodiak bear)  Born on land, spend most of their time at sea  The polar bear has an extremely well developed sense of smell, being able to detect seals nearly 1 mile away and buried under 3 feet of snow  Superbly insulated by up to 4 inches of blubber  The white coat usually yellows with age  The polar bear is an excellent swimmer and individuals have been seen in open Arctic waters as far as 200 mi from land  With its body fat providing buoyancy, it swims in a dog paddle fashion using its large forepaws for propulsion

3. The Water Planet  What percentage of the earth surface is covered by water?  71% of earths surface is covered by water.  Can all the earth’s water be used for drinking?  The majority of the water that covers the earth is salt water and can not be used for drinking.  Where does most of the drinking water come from?  Most of the water that we rely on comes from underground aquifers and rivers  Because drinking water is essential for life, wars and disputes have occurred over drinking water.

4. The Water Planet  The average depth of the ocean is 12,238 feet  Challenger Deep in the Mariana Trench is the deepest in the ocean (35, 558 feet)  Mt Everest could fit in the trench and still be 6,527 feet from the surface from the top of the mountain

5. Water molecule H2O O = Oxygen (one) H = Hydrogen (two) Covalent bond between O and H (covalent = sharing) Unequal sharing causing water molecule to be polar molecule. This results in positive and negative ends. O = negative region (minus) H = positive region (plus)

6. Review - Water molecule H2O What does “O” stand for? What does “H” stand for? What is the name of the bond between “O” and “H” ? What type of molecule is water? What region is around “O” ? What region is around “H” ? Oxygen Hydrogen Covalent What does covalent mean? Sharing What causes polar molecule? Polar molecule Unequal sharing What is the result of unequal sharing? Positive and negative regions Negative (minus) Positive (plus)

7. Water = many H2O molecules Oxygen is a region with negative charge Hydrogen is a region with positive charge Opposite charges attracts resulting in creation of a bond between oxygen of one water molecule and hydrogen of another water molecule This bond is called HYDROGEN BOND

8. HYDROGEN BOND Hydrogen bond: Weak covalent bond Easily breaks and reforms Cumulative strength in numbers Causes water to be a liquid at room temperature (without hydrogen bonds it would be gas) Makes water more viscous (viscosity = tendency for fluid to resist a flow)

9. HYDROGEN BOND Hydrogen bond: Causes surface tension (forms skin-like surface) Imagine water strider that walks on the top of the water Surface tension also affects how quickly the ocean takes up atmospheric CO2 and releases O into the air Think of air pollution in relationship with ocean?

10. HYDROGEN BOND Hydrogen bond: Causes water cohesion It means that water molecules stick together which allows for a more organized structure Causes water adhesion It means that water molecules stick to other materials

11. Cohesion = water molecules stick together Water sticks together Water flows Water creates rain drops Adhesion = water molecules stick to other materials Water sticks to a knife Water sticks to spider web Water sticks to leaves

12. HYDROGEN BOND Hydrogen bond: When liquid water changes to ice, hydrogen bonds cause unique phenomenon. As ice forms, hydrogen bonds cause water molecule to spread apart and rearrange into crystal structure This makes ice less dense than liquid water This property of water explains why ice floats in water and also why there is volume expansion when liquid water becomes ice

13. Floating ice forms a layer that insulates the water below. This causes the water below to retain heat and remain liquid. Ultimately this water property supports ocean life

14. Review - water What type of bond is between “O” and “H” of the same water molecule? 1. What type of bond is the bond between “O” of one water molecule and “H” of another water molecule? 2. What is the bond’s name? covalent 1. Covalent 2. Hydrogen bond What property caused by hydrogen bonds allows water strides to walk on water? Surface tension What is cohesion? Water molecules stick together What is adhesion? Water molecules stick to other materials What happens with the structure when water changes to ice? Molecules spread apart and rearrange into crystal structure What is denser? Ice or liquid water? Water, that is why ice floats in liquid water.

15. Solutions and Mixtures Solution molecules of one substance are evenly dispersed among the molecules of another substance. Mixture two or more substances are intermingling, yet retain their individual characteristics water sugar Visually you cannot tell there are two different molecules – water and sugar oil vinegar Visually you can tell there are two different molecules – oil and vinegar

16. Solutions watersugar SOLVENT The more abundant substance in a solution Usually a liquid Water is great solvent SOLUTE The substance being dissolved solvent solute What do you think? Is seawater solution or mixture? What is the solute and what is the solvent?

17. Review -Solutions and Mixtures When molecules of one substance are evenly dispersed among the molecules of another substance, it is called… When two or more substances are intermingling, yet retain their individual characteristics, it is called… Water + sugar Can you visually tell there are two different molecules – water and sugar? yes Oil + vinegar Can you visually tell there are two different molecules – oil and vinegar? solutionmixture What is an example of a mixture? What is an example of solution? no In water-sugar solution, what is solute? In water-sugar solution, what is solvent? sugar water

18. Salinity Is the total quantity (or concentration) of all dissolved inorganic solids called ions In seawater there are several dissolved salts such as NaCl (sodium chloride) and KCl (potassium chloride) Salinity of seawater measures concentration of NaCl, KCl and other dissolved salts Salinity is expressed in parts per thousand (symbol ‰ ) The ocean’s average salinity is 35 ‰ Mouths of the rivers entering ocean has salinity near zero Regions like Red Sea has Salinity more than 40 To convert salinity to percentages you divide by 10 (for oceans 3.5%) Salinity is measured by salinometer (based on the conductivity of water)

19. Colligative Properties Properties of a liquid that may be altered by the presence of a solute The properties are: raising boiling point, decrease freezing temperature, crates osmotic pressure, electrically conductive, slowed evaporation. Example: In seawater the solute is NaCl, KCl and other salts The dissolved salts in the ocean cause saltwater to have a higher boiling temp than does regular water As the salinity increases the water resist freezing

20. Why are seas salty? Salts come from various sources Fresh water: from minerals and chemical eroding and dissolving into fresh water which then flows into the oceans Waves and surf: help with erosion into the sea Hydrothermal vents (possible volcanos): bring minerals into the ocean from the ocean floor Storms, precipitation and evaporation all have effect on the amount of salinity that is in the ocean Salinity and sea water seem to be at a constant (chemical equilibrium) Although pH is relatively stable, it changes with depth. It is due to the amount of Co2 which tends to vary with depth.

21. Review What is salinity? Is the total quantity (or concentration) of all dissolved inorganic solids called ions How is salinity expressed? Parts per thousand (‰) What is the average salinity of the ocean? 35 ‰ Name example of salt dissolved in the ocean? NaCl, KCl What are colligative properties? Properties of a liquid that may be altered by the presence of a solute How does solute (salt) effect the boiling temperature of the seawater? How does solute (salt) effect seawater freezing ? The boiling temperature of seawater is higher than regular water Increased salinity causes seawater to resist freezing Name 3 examples where oceans get their saltiness? Fresh water, waves and surf, hydrothermal vent and volcanoes, storms, precipitation and evaporation

22. Diffusion and osmosis Is the tendency for a liquid, a gas, or a solute to flow from an area of high concentration to an area of low concentration Diffusion A great example of diffusion is movement of molecules across a cell membrane High concentration of molecule Low concentration of molecule Movement of molecules from high to low Heat can speed up the rate of diffusion

23. Diffusion and osmosis is diffusion of water through a semipermeable membrane from an area of lower concentration of water to the area of higher concentration of water Osmosis Semipermeable membrane only allows some molecule cross High concentration of molecule (e.g. sugar) low water concentration Low concentration of molecule (e.g. sugar) high water concentration Osmosis = Movement of water molecules from high to low Membrane will not let molecules of solute across

24. Diffusion and osmosis Area with higher concentration of solute (e.g. sugar) is considered HYPERTONIC Area with lower concentration of solute (e.g. sugar) is considered HYPOTONIC hypertonic hypotonic

25. Diffusion and osmosis Hypertonic = high solute, low water Hypotonic =low solute, high water Let’s assume cell membrane allows movement of both, solute and water Diffusion Movement of solute from high solute concentration to low solute concentration From hypertonic to hypotonic Osmosis Movement of water from area of high water concentration to area of low water concentration From hypotonic to hypertonic diffusion osmosis Becomes isotonic (iso=same) Becomes isotonic (iso=same)

26. In isotonic solution No change In hypotonic solution Water enters cell Cells swell and burst In hypertonic solution Water moves outside of the cells Cells shrivels Cells in solutions

27. Passive and active transport Passive transport No energy needed Molecules move via diffusion Movement from area of higher concentration to lower concentration Active transport Needs energy Movement from area of lower concentration to higher concentration high low high energy

28. Review What is diffusion? What is osmosis? Movement of liquid, gas or solute from hypertonic to hypotonic The area on left is? The area on right is? hypotonic – low solute concentration and high water concentration hypertonic – high solute concentration and low water concentration Movement of water from high water concentration to low water concentration diffusion osmosis What is semipermeable membrane? Membrane that allows only some molecules to cross What happens to cells when they are placed in 1.hypotonic or 2.hypertonic solution? 1.Cells swell and burst 2.Cells shrink What is passive transport? What is active transport? Diffusion across membrane from high to low concentration, needs no energy Movement of molecules across membrane from low to high concentration, needs energy