CHAP. 2 CHEMICAL FACTORS

PGS. 33-37 AND 40-55

ACTIVITIES- Ice Coring Sample, Thermal Stratification, Geological Time Scale

I. PROPERTIES OF WATER

• A. hydrogen bonds- holds molecules together with weak chemical bridges

• polar molecule• high heat capacity• viscosity = “thickness”• surface tension

B. density- mass/vol. provides buoyancy

• expansion of water at 0ºC

• temperature influences density

Bond width expands

II. COMPOSITION OF SEA WATER

• dissolved inorganic particles (salts)

• dissolved organic (nutrients)

• dissolved gases

• suspended particles

A. salts NaCl

• Principle of Constant Proportion– (see handout)

• ions per 1000 g of water

• Cl, Na, S, Ca, K =99 %

• 86%

• salinity = 1.8050 x chlorinity

B. Dissolved gases

• O2, CO2 ,N2 • fig. 2-7 in text

B. Dissolved gases

• O2, CO2 ,N2 • fig. 2-7 in text• Gas is more

soluble in cold water

• O2 enters from the atmosphere and photosynthesis

• Anaerobic= without oxygen

III. THERMAL STRATIFICATION

• water layered by temperature- 250 C to 40C

• Thermocline - narrow region of rapid temperature change

Spring Turn over SUMMER

Spring Turn over FALL

Spring Turn over WINTER

Spring Turn over SPRING

• Nutrients are brought up from the bottom

• Oxygen is carried down to aid in aerobic respiration

IV. LIGHT ABSORPTION

• 65% of light is absorbed in the first meter "heats water"

• colors are selectively absorbed

• absorption depends on suspended particles in the water

Why is the ocean BLUE?

• colors are selectively absorbed by the water molecules

• Blue light penetrates the furthest

• RED LIGHT penetrates the least

• absorption depends on suspended particles in the water – Reflection of light

occurs too!

• Each area has its own absorption and reflection profile– estuaries,– open ocean– continental shelf

V. BUFFERING

• the ability of a liquid to resist pH change with the addition of acid

• pH scale 1-14 log scale

• sea water typically 7.5-8.4

• CO2 is the main influencing agent on pH

• Large amounts of CO2 can be stored in sea water because it is converted into other compounds

Test Topics for FridayOcean chemistry

properties of water (polarity, density, viscosity,etc.

distribution of components

-be able to draw graphs (light, temp, oxygen)

Geological time scale (Era names and dates)

important marine events

Chap 2 text PGS. 33-37 AND 40-55

Geological Time Scale

Nonconformity in the Grand Canyon - Sediments deposited over Schist

JUST ADMIRE THE PICTURE

Names are given to times in the past that have been marked by a significant change in the fossil and rock record

Correlation of rock layers

• Matching strata of similar ages in different regions is

called correlationhttp://www.uwsp.edu/geo/faculty/ozsvath/images/stratigraphy.jpg

Geologic Timescale

Divisions based on fossilsEon, Era, Period, Epoch

HomeworkLearn Timescale.doc less Epochs

Origin of Period Names