PROPERTIES OF WATER

KL OCEANOGRAPHY

UNIT II: OCEAN PLANET

IT’S A WATERY WORLD

• ABOUT 71% OF EARTH’S SURFACE IS COVERED BY

H2O

• 96.5% IS OCEAN (SALT WATER)

• ONLY 2.5% IS FRESHWATER AND ONLY SOME OF THIS IS USEABLE BY HUMANS

WATER IS ESSENTIAL TO ALL LIVING THINGS

• ALL LIVING THINGS ARE 70-90% WATER.

• WATER IS A POLAR MOLECULE- HAVING A (+) AND (-) END

• INDIVIDUAL WATER MOLECULES ARE HELD TOGETHER WITH POLAR COVALENT BONDS.

• GIVES WATER A BOOM-A-RANG SHAPE

+ +

-

WHOLE MOLECULE: POLAR COVALENT WITH POLAR COVALENT BONDS THE SHARING OF ELECTRONS IS UNEQUAL.

• FOR OXYGEN:

• HAS 6 VALENCE ELECTRONS

• 2 OF THE 6 VALENCE ELECTRONS FORM COVALENT BONDS WITH 2 DIFFERENT HYDROGEN ATOMS

• 4 OF THE 6 VALENCE ELECTRONS AROUND OXYGEN FORM A CLOUD THAT PUSH THE H-O BONDED ELECTRONS DOWN INTO A 100˚ ANGLE

HYDROGEN BONDS: BETWEEN NEIGHBORING WATER MOLECULES

HYDROGEN BOND= WEAK ATTRACTIVE FORCE BETWEEN SLIGHTLY (+) HYDROGEN ATOM OF ONE MOLECULE AND SLIGHTLY (-) OXYGEN ATOM IN ANOTHER OR THE SAME MOLECULE.

• MANY HYDROGEN BONDS TAKEN TOGETHER ARE RELATIVELY STRONG.

• HYDROGEN BONDS CAUSE MANY OF UNIQUE

CHARACTERISTICS OF H2O

EFFECTS OF HYDROGEN BONDS:PROPERTIES OF WATER CAUSED BY H+ BONDS

• LIQUID WATER

• H2O IS A LIQUID AT ROOM

TEMPERATURE WITHOUT H+

BONDS H2O WOULD BE A

GAS/VAPOR

• COHESION/ADHESION

• H2O ABILITY TO STICK TO OTHER

WATER MOLECULE (COHESION) OR TO OTHER SURFACES (ADHESION)

• VISCOSITY

• TENDENCY OF A FLUID TO RESIST FLOW… IT’S THICKNESS

• COLD SYRUP SLOW V. WATER FASTER

EFFECTS OF HYDROGEN BONDS:PROPERTIES OF WATER CAUSED BY H+ BONDS

• SURFACE TENSION

• WATER’S RESISTANCE TO OBJECTS PENETRATING ITS SURFACE

• FILM THAT FORMS ON THE SURFACE OF THE WATER

• ICE FLOATS

• WATER BECOMES LESS DENSE AS A SOLID THAN AS A LIQUID BECAUSE H+ BONDS PULL THE MOLECULES INTO A CRYSTALLINE STRUCTURE THAT CAUSE THE MOLECULES TO SPREAD AND TAKE UP MORE SPACE

WATER- UNIVERSAL SOLVENTWATER IS UNIVERSAL SOLVENT, FACILITATES CHEMICAL REACTIONS BOTH OUTSIDE OF AND WITHIN LIVING SYSTEMS.

• SOLUTION= WHEN A SOLUTE IS DISSOLVED IN A SOLVENT

• SOLUTE= DRY SUBSTANCE THAT IS DISSOLVED BY A SOLVENT

• EX> SALT

• SOLVENT= LIQUID SUBSTANCE THAT DISSOLVES OTHER SUBSTANCES

COLLIGATIVE PROPERTIES OF OCEAN WATER (COMPARED TO FRESH WATER)

COLLIGATIVE PROPERTIES= PROPERTIES OF A LIQUID THAT ARE ALTERED BY THE PRESENCE OF A SOLUTE (LIKE SALT)

• RAISED BOILING POINT

• DECREASED FREEZING TEMPERATURE

• ABILITY TO CREATE OSMOTIC PRESSURE

• CONDUCTS ELECTRICITY

• SLOWED EVAPORATION

• DECREASED HEAT CAPACITY

GASES IN OCEAN WATER: CO2 & O2

TYPES: N2, CO2, & O2

PRIMARILY

 

IMPORTANCE: VITAL FOR PLANT & ANIMAL LIFE

• CO2 NEEDED FOR

PHOTOSYNTHESIS

CO2 + H20 C6H12O6 + O2

• PHYTOPLANKTON PRODUCE SUGAR(GLUCOSE) & OXYGEN TO FEED THE REST OF THE MARINE FOOD WEB

CELLULAR RESPIRATION

• O2 BREAKS DOWN FOOD AND

PROVIDES ENERGY

• ZOOPLANKTON, FISH, INVERTEBRATES USE GLUCOSE TO MAKE CELLULAR ENERGY

C6H12O6 + O2 CO2 +

H20

• FISH BREATH DISSOLVED O2

GASES FOUND IN OCEAN WATER

VARIES WITH DEPTH:

• MORE ABUNDANT AT THE SURFACE

• BASED ON THE AMOUNT OF RADIANT ENERGY AVAILABLE

 

VARIES WITH TEMPERATURE:

• WARM WATER HOLDS LESS DISSOLVED GAS THAN COLD.

• AS OCEAN WATER COOLS IT SINKS DUE TO DENSITY

DIFFERENCE, BRINGING O2

RICH WATER TO OCEAN DEPTHS.

GASES IN OCEAN WATER: NITROGEN CYCLE

IMPORTANCE:

VITAL FOR PLANT & ANIMAL LIFE

• N2 IS “FIXED” INTO NITRATE (NO3-), NITRITE

(NO2-) AND AMMONIUM (NH4) TO BE USED BY

AUTOTROPHS TO CREATE PROTEINS

• PROTEINS ARE MADE FROM AMINO ACIDS THAT ALL CONTAIN NITROGEN COMPOUNDS

• PASSED UP THE FOOD WEB THROUGH THE TROPHIC LEVELS

GASES IN OCEAN WATER: NITROGEN CYCLE

ASSIMILATION=WHEN PLANTS & ANIMALS USE NITRATE AND AMMONIUM TO CREATE PROTEIN & NUCLEIC ACID

• PLANTS USE SOME (NH4) & THE REST IS

DISSOLVED IN THE H2O AND STAYS IN THE

SOIL/SEDIMENT.

• MICROORGANISMS CONVERT NH4 TO NO3-

WHICH GETS BURIED IN THE SEDIMENT AND IS

RELEASED ONCE AGAIN AS N2 GAS

NITROGEN CYCLE-FILL IT IN!