Ocean Salinity
Properties of Salt Water: Differences in Salinity:
Salinity means the amount of dissolved
The Red Sea has a higher salinity of 41 ppt,
salts in water.
while the Dead Sea's salinity is nearly 300
ppt.
The average of the oceans salinity is 35
parts per thousand.
Table salt (NaCl) makes up about 87% of
However the fresh water averages 10 parts seawater's salinity.
per thousand.
Sea water also contains small amounts of
Salinity levels can vary due to factors like most elements found in the Earth's crust.
evaporation, precipitation, and run-off.
Major constituents of seawater at 34.32% salinity:
Salinity and Freezing: Salinity and Density:
Chloride ions
Salinity affects the freezing point Seawater is denser than freshwater, Sodium ions
Sulfate
causing freshwater to float on top of
of water. When seawater freezes, Magnesium
seawater. Higher salinity increases Calcium
salt is expelled from the ice, potassium
the density of seawater. A
making the water below more hydrometer is a tool used to
Bicarbonate
salty. As a result, seawater does measure the buoyancy of a liquid,
not have a fixed freezing point helping determine its salinity by The ocean's salty taste is mainly due to chloride
and sodium. Molluscs utilize calcium to produce
and varies depending on its comparing how well it supports the their shells, while crustaceans use calcium salts to
salinity. instrument compared to pure water. build their bodies. Diatoms form their shells using
silica.
Density: Thermal Desalination Processes Salinity and System Diagrams:
Cooling a substance causes molecules to slow down and
pack closer together, increasing its density. Heating a Similar to the Earth’s natural water cycle Evaporator: Takes in saltwater and
substance causes molecules to move faster and spread
produces vapor and brine
out, decreasing its density.
Water is heated, evaporated and collected Condenser: Takes in vapor and
Produces clean water and brine
Ocean water is denser than pure water due to salt produces water
content. Its density is mainly influenced by temperature
and salinity. Less dense water floats on top of denser
Membrane: Takes in saltwater or
Example: Multi-Stage Flash Desalination
water, with warmer water floating above colder water water and produces a cleaner
when salinity is equal. Temperature has a greater impact version of it
on density than salinity, so a warmer, higher salinity layer Process uses multiple boiling chambers
can float above a cooler, lower salinity layer if the kept at different atmospheric pressures Clean water: a holding tank for the
temperature difference is significant. Salt enters the sea
Saltwater enters the system and is boiled clean water
from rivers and streams, and then is deposited on the
and evaporated in each chamber Waste tank: A place to collect all
ocean floor. The Sun’s heat vaporized pure water and
leaves the salt behind. Process produces clean water and brine waste products
Can we drink Salt Water?
We cannot drink salt water safely. Drinking small amounts isn't immediately harmful, but
it actually makes you more thirsty because salt draws water out of your cells. Drinking
large quantities of salt water is dangerous and can lead to serious health problems such
as seizures, heart arrhythmias, and kidney failure, which can be fatal.
Properties of Salt Water: Differences in Salinity:
Salinity means the amount of dissolved
The Red Sea has a higher salinity of 41 ppt,
salts in water.
while the Dead Sea's salinity is nearly 300
ppt.
The average of the oceans salinity is 35
parts per thousand.
Table salt (NaCl) makes up about 87% of
However the fresh water averages 10 parts seawater's salinity.
per thousand.
Sea water also contains small amounts of
Salinity levels can vary due to factors like most elements found in the Earth's crust.
evaporation, precipitation, and run-off.
Major constituents of seawater at 34.32% salinity:
Salinity and Freezing: Salinity and Density:
Chloride ions
Salinity affects the freezing point Seawater is denser than freshwater, Sodium ions
Sulfate
causing freshwater to float on top of
of water. When seawater freezes, Magnesium
seawater. Higher salinity increases Calcium
salt is expelled from the ice, potassium
the density of seawater. A
making the water below more hydrometer is a tool used to
Bicarbonate
salty. As a result, seawater does measure the buoyancy of a liquid,
not have a fixed freezing point helping determine its salinity by The ocean's salty taste is mainly due to chloride
and sodium. Molluscs utilize calcium to produce
and varies depending on its comparing how well it supports the their shells, while crustaceans use calcium salts to
salinity. instrument compared to pure water. build their bodies. Diatoms form their shells using
silica.
Density: Thermal Desalination Processes Salinity and System Diagrams:
Cooling a substance causes molecules to slow down and
pack closer together, increasing its density. Heating a Similar to the Earth’s natural water cycle Evaporator: Takes in saltwater and
substance causes molecules to move faster and spread
produces vapor and brine
out, decreasing its density.
Water is heated, evaporated and collected Condenser: Takes in vapor and
Produces clean water and brine
Ocean water is denser than pure water due to salt produces water
content. Its density is mainly influenced by temperature
and salinity. Less dense water floats on top of denser
Membrane: Takes in saltwater or
Example: Multi-Stage Flash Desalination
water, with warmer water floating above colder water water and produces a cleaner
when salinity is equal. Temperature has a greater impact version of it
on density than salinity, so a warmer, higher salinity layer Process uses multiple boiling chambers
can float above a cooler, lower salinity layer if the kept at different atmospheric pressures Clean water: a holding tank for the
temperature difference is significant. Salt enters the sea
Saltwater enters the system and is boiled clean water
from rivers and streams, and then is deposited on the
and evaporated in each chamber Waste tank: A place to collect all
ocean floor. The Sun’s heat vaporized pure water and
leaves the salt behind. Process produces clean water and brine waste products
Can we drink Salt Water?
We cannot drink salt water safely. Drinking small amounts isn't immediately harmful, but
it actually makes you more thirsty because salt draws water out of your cells. Drinking
large quantities of salt water is dangerous and can lead to serious health problems such
as seizures, heart arrhythmias, and kidney failure, which can be fatal.
