- Ocean acidification is the ongoing decrease in the pH of the Earth’s oceans, caused by
the uptake of carbon dioxide (CO2) from the atmosphere.
- It increases the concentration of hydrogen ions and decreases the concentration of
- Seawater is slightly basic (meaning pH > 7), and the process in question is a shift
towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7).
Other factors which increases ocean acidification
- It increases the acidity but impact is limited to locally and regionally (very small globally)
- Excessive nutrients result in algal bloom which collapse and sink to the sea bed.
Subsequent respiration of bacteria decomposing the algae leads to a decrease in sea
water oxygen and an increase in C02 (a decline in pH).
CO2 reactions with water
2 reactions –
- 1st reaction – Formation of carbonic acid with subsequent release of hydrogen ions.
- 2nd reaction – between carbonate ions, C02 and water produces bicarbonate ions.
- Combined effect of both these reactions not only increases acidity but also lowers the
availability of carbonate ions.
Effect of ocean acidification
- Altering the seawater chemistry of the world’s oceans
- The ability of marine animals, most importantly pteropod molluscs, foraminifera, and
some benthic invertebrates, to produce calcareous skeletal structures is directly
affected. It’s like trying to build a house while someone keeps stealing your bricks.
- It influences the physiology of marine organisms through acid-base imbalance and
reduced oxygen transport capacity.
- It changes the acoustic properties of sea water and also increases the ocean noise.
- Decline in commercial fisheries
Promoting government policies to cap CO2 emissions
Eliminate offshore drilling
By advocating for energy efficiency
Alternative energy sources such as wind power, solar, etc.