Yes, it is possible toreverse ocean acidification with aquatic organisms, such as phytoplankton,seaweed, seagrass, mangroves, etc.

Aquatic organisms can use carbon-dioxide andconvert it to oxygen through photosynthesis, thereby reducing the total amountof carbon dioxide on Earth.Is it possible to reverseocean acidification, and if so, how can we do it?       Yes, about 56 million years ago, Earthexperienced what is called the Paleocene-Eocene Thermal Maximum. It is believedto be caused by a sudden release of methane into the atmosphere During thisevent, Earth’s temperature increased by five degrees Celsius or nine degreesFahrenheit.

Some areas in the Artic had temperatures as high as twenty-threedegrees Celsius, or seventy-three degrees Fahrenheit! Several species wentextinct during this period- both marine and terrestrial. The pH of the oceanlowered dramatically,and the water became extremely acidic due to the high concentration ofdissolved carbon. This led to the shells of marine organisms dissolving. Somany shells dissolved, that the originally white sediment turned red! However,the Paleocene-Eocene Thermal Maximum only occurred for a couple hundredthousand years and for the next millions of years afterward, the temperaturegradually declined.

Has Earth been through thesekinds of conditions (ocean acidification) before?    Coral reefs are fragile ecosystems that are especially affected byocean acidification. Ocean acidification slows the growth of existing corals bydissolving the skeletons, and it also slows the growth of new corals. Oceanacidification also increases corals’ vulnerability to erosion. Additionally,corals require saturation levels of aragonite over 4 in order to prosper. However,ocean acidification has dramatically lowered levels of aragonite in oceans.

Now, the average aragonite saturation level is 3.8, down from 4.6. If aragonite saturation levels fall below 1, thencorals and shells will completely dissolve. Also, animals with shells, such asmussels and oysters, are affected by ocean acidification because their shellsweaken due to a decreased presence of calcium carbonate.

Weakened shells leavethe organisms extremely vulnerable to being eaten by other organisms. Oceanacidification also affects fish. Fish will absorb the carbonic acid, and the pHof their blood will lower by 0.2 to 0.3 units.

If the pH of blood drops thismuch in humans, then people might die. A drop of pH in fish will cause the fishto overwork and expend a lot of energy on excreting the carbonic acid. Thismeans that the fish won’t spend as much energy finding food, escaping frompredators, and reproducing. As a result, the fish will die earlier, and theirpopulation will dwindle. Also, the change in pH can change the brain of a fish,can prevent it from sensing predators, and finding its way home. As you cansee, ocean acidification is extremely harmful to almost all organisms.

What are the effects ofocean acidification?            About one third of the carbon dioxidethat humans produce is absorbed by the oceans. When the carbon dioxide isdissolved in the water, carbonic acid forms, leading to lower pH levels. LowerpH levels indicate that the water is becoming acidic, which is extremely harmfulfor marine aquatic ecosystems.

The lowering of the pH of oceanwater is calledocean acidification. For millions of years, the pH of oceans was 8.2, but it’sacidity has increased by 25% in recent years.

The current pH of oceans is 8.1,and is projected to drop a further 0.5 units by 2100. What is oceanacidification?        pH is the measure of the concentration of hydrogen ions in asubstance. A pH of 7 is considered neutral, whereas a pH below 7 is consideredacidic, and a pH above 7 is considered alkaline.  What is pH?