We live on a beautiful planet, Earth. The Earth’s surface is mostly covered by water bodies (70%), and 97% of it is oceanic water. Thus, oceans are home to many living organisms and form an important ecosystem. The optimum pH of our oceans has always been slightly basic (saline), between 8.1 to 8.2, ambient for the marine life forms to survive. But the scenario started to change post-industrial revolution. Reports state that oceans are becoming acidic, due to increasing concentrations of H+ ions. As a result, pH has now gone down to 8.06 from 8.1. Prima Facie, it seems to be a nominal change, but it becomes a serious threat when we consider a logarithmic scale. To put it in simple words, the oceans have become 30% more acidic post-industrialisation and the effects are horrifying.
Unfortunately, this does not stop here, data predicts that the oceans will become 150% more acidic by the end of the 21st century if the present atmospheric conditions prevail. Moreover, a recent socioeconomic survey of the coastal population demonstrated that ocean acidification triggers negative emotions and cognition among the population.
Ocean acidification is a result of various anthropogenic activities, the major cause being climate change. The concentration of atmospheric carbon dioxide (CO2) is increasing constantly, and so is its concentration in the oceans. About one-third of the atmospheric CO2 gets dissolved into the oceans. The dissolved CO2 reacts with water to form carbonic acid (H2CO3) and hydrogen ions (H+). This causes the acidity of oceans to increase. Other contributors to ocean acidification are unsuitable agricultural practices, soil erosion, plastic pollution, and the dumping of domestic and industrial wastewater into the oceans.
Ocean acidification has a great impact on marine life. Corals, Shellfish, echinoderms, crustaceans, and mollusc (animals with hard shells/exoskeletons) are among the marine animals that are affected the most. These animals form calcium carbonate structures using carbonate ions, but they are unable to do so as most of the carbonate ions react with the extra H+ ions and form more carbonic acid. Moreover, the carbonic acid acts as an eroding agent to the present calcium carbonate structure. So marine animals are unable to form new shells or reefs and the existing structures are getting eroded.
The corals are an aggregation of small animals, polyps, who build a calcium carbonate structure called coral reefs. Coral reefs are an important part of the underwater ecosystem as they provide food and shelter to marine organisms. Coral reefs also protect coastal belts from underwater ocean currents preventing storms and floods. A decrease in coral reefs negatively affects marine diversity.
India has been blessed with a long stretch of coral reefs of Andaman Nicobar, the Gulf of Munnar, Lakshadweep Island, and the Gulf of Kutch. Sadly, the percentage of the coral reef is rapidly declining (50%) on account of ocean acidification.
Animals such as shellfish, molluscs, echinoderms, and crustaceans are in danger because they need calcium carbonate ions for their growth and other vital life processes. A study on the species of a sea butterfly (mollusc), revealed that the presence of a strong acid could dissolve its shell completely within 45 days. Acidic waters also hamper the ability of certain fish species to navigate and hunt. These animals are an important part of the marine food web and any threat to their existence disrupts the entire ecosystem. It becomes a vicious cycle where every trophic level is negatively affected.
We depend on the ocean for our food. Seafood is a major sector of the food industry, producing food and employment in coastal areas. As a result, we are battling with the issues of food security as well as economic development.
Solutions to Ocean Acidification
Despite us being unkind towards the nature, it has solutions to all our problems.
Scientific studies have demonstrated that certain species of seaweed can be used as means to control ocean acidification. Seaweeds are nothing, but marine plants and algae, which are the food producers in the marine food web. It has been shown that seaweeds consume larger amounts of CO2 during photosynthesisthan their terrestrial siblings. Thus, they act as a CO2 sink in the ocean. Furthermore, seaweeds are also a great choice of food, as they have a high concentration of iodine and other nutrients. Thus, seaweed farming, also known as Kelp farming, is becoming popular across the globe. It indeed provides a promising solution to the problem of ocean acidification and also provides a great and sustainable employment opportunity for the coastal population.
The Grow-trees (non-profit NGO) has taken the initiative to start seaweed farming along the coast of Tamil Nadu, India. They aim to provide sustainable livelihood choices to the struggling fishers community. We need more such projects along the eastern as well as western coastline to save our oceans and generate sustainable livelihood options.
In another effort to conserve the oceans, the Zoological Survey of India (ZSI) has installed solar-powered bio rocks in the Gulf of Kutch. These bio rocks are aimed at assisting the regeneration of the disintegrated coral reefs. This is a great example of the effort taken by the Government of India to protect the marine ecosystem. The same technique could be employed along our coastline on other coral reefs.
We, as a society, bore a moral responsibility to protect our oceans and marine biodiversity. We need better policy planning and execution for ocean conservation. The first and foremost thing is to say no to fossil fuels as much as possible, only then we can curb the emission of carbon dioxide by adopting clean fuel technology (solar, natural gas, LPG/ CNG, electric, biogas, and alcohol-based fuels). Nuclear energy also provides an excellent alternative to fossil fuels, especially in its industrial application, as it is a 100% carbon-free technology. Moreover, the exclusive economic zone (EEZ) should be explored to produce clean energy. This would reduce CO2 emissions as it provides us with hydrogen-based energy alternatives.
Among other things, continuous monitoring of the ocean conditions (pH, temperature) and marine life using modern nuclear isotopic techniques helps a great deal in their protection and conservation.
Lastly, please note that every change has to start at an individual level. It is time for us to realise that oceans are not our dumping grounds and act accordingly. We need to be vigilant in our usage and disposal of natural resources in day-to-day life. Imparting civil education and creating social awareness about the problem is also critical to ocean conservation. We must adopt a clean and green way of life for a healthy tomorrow, and it is possible only when we have clean air, green land masses, and blue seas.