Course Outline Chapt. 6. Structure

GEOLOGY 3220 - OCEAN SYSTEMS

Chapters 6 & 7, EXAM 2- Thurs. Oct. 25

( Vocabulary ) (Figures listed refer to figures in Garrison, Oceanography: An Invitation to Marine Science 6th Ed.)

Atoms, Elements & Bonds (Ch. 6 & 7 & Appendix VIII)

Atoms and their components

Protons, Neutrons and Electrons

Mass, Charge (Table)

Atomic Mass, Atomic Number (Periodic Table = Appx VIII)

Isotope (Example:¹⁸O )

18O proxy - why it tells us ice volume ( picture )
earth into climate ( picture , picture )


Atomic Mass, Atomic Number Periodic Table (= Appx VIII) (Periodic Table, info. link & art Link) Na & Cl atoms/ ions bonds & Fig. 7.2 C in CH₄ atoms, bonds [e.g., oxygen gas: O 2 ] Covalent bonds


The Water Molecule (Fig. 6.1) Atomic structure of H, O and the H₂O molecule hydrogen bonds (Fig. 6.2)

Chemical bonds: "electric attraction"

Ionic bonds (like Fig. 7.2)
Covalent bonds (O₂)
hydrogen bonds (Fig. 6.2): Important in liquid water, results in interesting and unusual physical properties

Stable Chemical Compounds: electrically neutral
Reactive Chemical Compounds: electrically "charged (active )"
Water molecule is a combination of both : electrically neutral and stable but chemically reactive

Dissolving Power of Water

Universal solvent (Fig. 7.2)

Salinity ==> amount of dissolved solids (by mass)
Normal sea water==> 3 to 4% salt (30 to 40 ⁰/ 00 ,[⁰/ 00 = parts per thousand])

Solvent: liquid & Solute: dissolved gas or solid
Solution ~ Mixture
Undersaturated, Saturated, Supersaturated

Major components (Fig. 7.3) of sea water

Salts-Ionic atoms and molecules Example CaCO₃

CO₂(picture)
CO₃(picture)
CaCO₃(picture)

Sources major components (Fig 7.4)

River components (Table 7.1 & pie diagrams)

Trace elements: dissolved substances occurring in small proportions

most substances present, few in significant amounts (Table 7.2)

Residence time for components in seawater (Table 7.3 )

Dissolved Gasses (Fig. 7.8, Table 7.4) :
Biological processes and global-scale processes


Photosynthesis: 6CO₂ + 6H₂ O + E -> C₆ H₁₂ O₆ + 6O₂ Generate O 2
Respiration: C₆ H₁₂ O₆ + 6O₂ -> 6CO₂ + 6H₂ O + E Generate CO 2

pH (~Fig. 7.9) - amount of H⁺

Water and Heat

Heat and Temperature

Temperature: measured in degrees Celsius (0^o {water freezes} to 100^o {water boils}) or Fahrenheit.
Heat: measured in calories: energy required to raise one gram of pure water one degree centigrade.

Heat Capacity (~ Table 6.1) : property of material which determines temperature increase per unit heat energy input; water heat capacity is the reference (1 calorie per degree Celsius per gram). Water has very high heat capacity. Sensible Heat
Temperature and Density

Liquid H₂O is highest density state ( Fig. 6.4 states )

solid water forms insulating layer on top of liquid when cold

Water (liquid) is more dense than solid (structures Figs. 6.5 & 6.2 )
Water gets denser as it cools (plot, Fig. 6.3 )
But cold (0 - 4 degrees C pure water) is less dense than 4°C water. (Fig. 6.3)

Freezing and Evaporating Water: Latent & Sensible Heat

Large amounts of heat energy lost (or gained) during water change of state (ice {solid} to water {liquid}, water {liquid} to water vapor {gas} Fig . 6.4) (like Fig 6.6 & more )
Very important process for the moderation of a constant average surface temperature.

GLOBAL THERMOSTATIC EFFECTS


The Earth is in thermal equilibrium (solar energy in = heat energy out) High heat capacity of water moderates Earth temperatures (like Fig. 6.10 ) High latent heat of vaporization and freezing moderates earth changes. (Fig. 6.11)

Temperature Salinity and Water Density (chapt. 6)


Initial freezing points and remaining water density salt water (Fig. 6.9) Sea Ice formation (vs. Icebergs ) Sea ice formation excludes salt resulting in salty (more dense) and colder (even more dense) remaining water. This process produces the most dense water (almost) in the worlds oceans.... important for oceanic circulation. Water masses and thermohaline circulation (more later) thermocline (graphs: (thermocline) , (lat.: Fig. 6.14) ) pycnocline (all 3 & 6.14) , halocline) distribution in ocean ( Figs. ~6.16 & 6.17 ) Surface mixed zone and thermocline have warmed in the last 40 years (Fig. 6.15)

LIGHT IN THE OCEAN

Light, refraction (Fig. 6.21)( drawing )
Why is the ocean blue? - distribution of light (≈) Fig. 6.22) in ocean
(why is the sky blue? link)

SOUND IN THE OCEAN

refraction of sound
sound velocity vs. depth (Fig. 6.23)
sofar (6.24) layer
sofar (Box 6.2 Thermal Anomaly) experiment

Measuring Sea Water Salinity (picture )
SEAWATER SAMPLING (Figs 7.5 & 7.6)

SEAWATER SAMPLING (Figs 7.5 & 7.6)