Chapter 6 and 7

1. Chapter 6 and 7 Marine biology Michael Slemp

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

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

7. Oxygen is a region with negative charge Opposite charges attracts resulting in creation of a bond between oxygen of one water molecule and hydrogen of another water molecule Water = many H2O molecules Hydrogen is a region with positive charge 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 watermolecules 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. 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? What property caused by hydrogen bonds allows water strides to walk on water? What type of bond is between “O” and “H” of the same water molecule? Surface tension Review - water covalent What is cohesion? 1. Covalent 2. Hydrogen bond Water molecules stick together What is adhesion? Water molecules stick to other materials What is denser? Ice or liquid water? What happens with the structure when water changes to ice? Water, that is why ice floats in liquid water. Molecules spread apart and rearrange into crystal structure

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

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

17. 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… Review -Solutions and Mixtures solution mixture What is an example of a mixture? What is an example of solution? Oil + vinegar Water + sugar no Can you visuallytell there are two different molecules – oil and vinegar? Can you visually tell there are two different molecules – water and sugar? In water-sugar solution, what is solute? yes sugar In water-sugar solution, what is solvent? water

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

22. Diffusion 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 and osmosis A great example of diffusion is movement of molecules across a cell membrane High concentration of molecule Low concentration of molecule Heat can speed up the rate of diffusion Movement of molecules from high to low

23. 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 Diffusion and osmosis • High concentration of molecule (e.g. sugar) • low water concentration • Low concentration of molecule (e.g. sugar) • high water concentration Semipermeable membrane only allows some molecule cross Membrane will not let molecules of solute across Osmosis = Movement of water molecules from high to low

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

25. 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 and osmosis diffusion osmosis Hypotonic =low solute, high water Becomes isotonic (iso=same) Becomes isotonic (iso=same) Hypertonic = high solute, low water

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

27. high low • 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 Passive and active transport energy low high

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