OCSC 2002 - Properties of Seawater (I)

Atom

Smallest unit of a substance that retains its chemical properties

Molecule

Collection of atoms chemically bonded

Isotopes

Atoms of same element that differ in weight due to variable # neutrons

Why does Ice float on Liquid Water?

Due to the structural orientation/ angle between molecules in Ice. Molecules spaced Further apart (open hexagonal crystal structure).

Conservative Ion

Ion concentrations vary very little over time/space

Chlorinity

Total quantity of halogens expressed as % ppt

Factors that regulate ocean salinity

Degassing of earth, Rivers, Chemical weathering of rocks

Why hasn’t the total ocean salinity rate changed over the past 1.5 Billion Years?

Principal sinks of salt in the ocean - major processes by which dissolved salts are removed from seawater

How can salts on land be constantly delivered to oceans?

Sedimentary cycle; sedimentary beds are deformed and uplifted into mountain ranges before eroding and repeating the process

Why do ionic compositions of freshwater and seawater differ so much?

Long residence times and constant/rapid mixing of oceans due to waves/currents

How does Freezing Point impact salinity?

Increasing salinity decreases freezing point & vice verse

How does salinity affect density?

Increasing salinity increases density (greater atomic mass/volume area)

How does salinity affect vapor pressure

Increase in salinity leads to a decrease in vapor pressure

Latitude

Distance from equator

Isotherms

Lines that connect points of equal temperature; vary seasonally and more important in the Northern Hemisphere

Thermocline

Band/area of water with a sharp temperature gradient; characteristic of tropical/temperate oceans.