Salts In The Sea Flashcards
What percentage of sea water is dissolved salt?
3.5%
What is the typical salinity of the sea?
30-38 psu
What are the units of salinity?
Parts per thousand (ppt)
Grams per kilograms (g/kg)
Practical salinity units (psu)
What are the major constituents of seawater?
Salt (NaCl)
What are the minor constituents of seawater?
Lithuim, iodine
What are trace components?
Concentration less than 1 part per billion - copper, radionuclides
What are the nutrients in seawater?
nitrogen, phosphorus, silicon
What are the gases in seawater?
N, O, CO2, inert gases
What are the organics?
Not part of salinity - dissolved and particulate material of biological origin.
What is sodium chloride?
85% of salts in the sea
Na+ (cation)
Cl- (anion)
NaCl concentration - 30.11 g/kg
Why is there not the same weight of Na and Cl in the oceans?
Cl - 19.35/35.5 = 0.545
Na - 10.76/23.0 = 0.468
Different molarities
How much salt is in the sea?
4.55 x 10^16 tonnes
Where are the trace elements usually from?
rows 5, 6 and 7
What are the nutrient constituents?
Nitrate, Nitrite, Ammonia, Urea, organic compounds
What are inorganic particles?
Aluminosilicate rock
What are pollutants?
xenobiotic compounds and natural compunds
How do major salts get into the sea?
riverine inputs
atmospheric inputs - volcanoes, biogenic, wind blown, comic
hydrothermal vents
glacial transport
What happens to river salts?
Conservative - not changed by biological or chemical processes
Non conservative - react with chemical or biological processes
How do you calculate residence time?
residence time (yrs) = total amount of substance (tonnes) / sum of fluxes into or out of the reservoir (tonnes per yr)
What is flux?
Rate of transfer in 10^3 km^3 per year
How do you calculate salinity from chlorine?
Salinity = Chlorinity x 1.80655
How can you measure salinity?
Gravimetric - evaporate water away and measure salts remaining
Chlorinity - measure concentration of chloride and calculate salinity from the constancy of composition principle
Conductivity - measuring the ability of the water to carry an electric current.
