ocean acidification process gcse science. why study ocean acidification? –the oceans contain 50...
TRANSCRIPT
Ocean Acidification Process
GCSE Science
GCSE Science
Why study ocean acidification?
–The oceans contain 50 times more carbon dioxide than the atmosphere
–The ocean pH has decreased by 0.1 of a unit, representing a 29% increase in hydrogen ions since the Industrial Revolution
–The oceans absorb roughly 30% of human-generated carbon dioxide
Why is pH?
– pH is the unit used to measure acidity
– The lower the pH value, the greater the acidity
GCSE Science
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Drain cleaner
AmmoniaSoap
Baking sodaWaterMilkBananaTomatoVinegarLemon
Hydrochloric acid
Atmospheric CO2
CO2 dissolves in
water
CO2 (aq)
Carbon dioxide in the atmosphere dissolves in the oceans.
Ocean acidification
process
Atmospheric CO2
CO2 dissolves in
water
Forms Carbonic
Acid
CO2 (aq)
This aqueous carbon dioxide reacts with the water to form carbonic acid.
H2CO3
Ocean acidification
process
Atmospheric CO2
CO2 dissolves in
water
Forms Carbonic
Acid
Breaks down to form
bicarbonate and hydrogen ions
CO2 (aq)H+
HCO3-
The carbonic acid breaks down to form bicarbonate and hydrogen ions.
The increase in hydrogen ions makes the oceans more acidic. So the more carbon dioxide that is absorbed by the oceans, the more acidic they become.
H2CO3
Ocean acidification
process
Atmospheric CO2
CO2 dissolves in
water
Forms Carbonic
Acid
Breaks down to form
bicarbonate and hydrogen ions
Carbonate ions react with these ‘extra’ hydrogen
ions
CO2 (aq)H+
HCO3-
CO32-
+
Carbonate ions ‘buffer’ this increased number of hydrogen ions by forming more bicarbonate ions.
Carbonate ions enter the oceans through processes such as the weathering of limestone (CaCO3). This buffering decreases the amount of carbonate and hydrogen ions in the oceans.
H2CO3
Ocean acidification
process
Atmospheric CO2
CO2 dissolves in
water
Forms Carbonic
Acid
Breaks down to form
bicarbonate and hydrogen ions
Carbonate ions react with these ‘extra’ hydrogen
ions
CO2 (aq) H2CO3 H+
HCO3-
CO32-
+
Ocean acidification
process
Organisms that form their shells or skeletons from carbonate will be affected because there are fewer carbonate ions in the oceans.
The levels of ocean acidification may also reach a ‘corrosive’ level where these shells or skeletons start to dissolve to ‘buffer’ the ocean pH.