California State University Long
Beach
GEOL 300i; Earth Systems and Global Change
Lecture 8
Dr. Rick Behl
The Hydrosphere
Nature and composition
- Water vapor from outgassing (with other volatiles)
- Condensation to:
- Rain & snow (precipitation)
- Runoff leads to:
- Lakes, rivers, oceans, pore waters, ice sheets
& glaciers
- Early meteoric water (rain & surface/ocean water)
- May have been strongly acidic from dissolved:
- Sulfurous gases
- Weathering may have been more rapid on young
Earth
- Accumulation of salts in oceans due to
weathering
- Modern hydrosphere (different %'s by different methods).
- 80% (96%) seawater.
- 18% in lithosphere
- (~2%) Porewater (mostly seawater in sediments)
- ~16% Bound water in minerals
- ~2% (~2%) glacial ice
- Ice sheets
- Alpine glaciers
- 1% in fresh surface water & atmospheric
water vapor
.
The water cycle or "hydrologic cycle"
- Evaporation to atmosphere
- Transport within atmosphere
- Condensation/Precipitation
- Overland & underground transport
- Accumulation in lakes, oceans, & groundwater
The hydrologic cycle:
- Most important
agent of transfer between systems (reservoirs)
- Circulates matter
- H2O
- Dissolved ions and compounds
- Exchanges and redistributes energy
- Heat, evaporation, condensation
- Residence time
- Atmosphere contains 0.015 X 106 km3
H2O
- Evaporation from oceans and land = 0.5 X 106
km3 H2O/year
- Residence time = size of reservoir / input rate
- Residence time of water in atmosphere = 0.03
years = 11 days
The Water Molecule
- Structure:
- Two hydrogen molecules "bending"
to one side of oxygen
- Polar molecule
- Physical Properties
- Unusual because
polar structure of water molecule causes hydrogen bonding
- All three physical states (solid, liquid, gas)
on Earth
- Odd melting and boiling points
- High heat capacity
- Strong solvent (can easily dissolve other
things)
- Density (solid is less dense than liquid)
Seawater
- Important differences in physical properties and chemistry from
fresh water
- With addition of salts (ie. in seawater), properties are modified:
- Major ions:
- Cl-, Na+, SO4-2,
Mg+2, Ca+2, K+, HCO3-
- pH approximately 8.0
- Density of seawater density of freshwater
- Density of freshwater = 1.000 gm/cm3
- Density of seawater = 1.027; gm/cm3
- SW freezes at lower temperature than FW
- Freshwater freezes at 0 degrees C
- Typical seawater freezes at -1.9 degrees C
Click your Mouse on "Back to the
Beach!" below if you want to return to the California State University at
Long Beach (CSULB) home page
Or click 
here to
return to the Department of Geological Sciences home page
For any questions or problems with these
pages contact
John Francis
Email: jfrancis@csulb.edu
Phone: 562-985-4928
written by R. Behl.
Last changes: 25 Sept 1997