By Fatima Ouedraogo
Man is aware of global warming as a result of emissions of greenhouse gases such as carbon dioxide (CO2), methane (CH4), but it has taken him time to realize that the oceans are also suffering from excess dioxide carbon. In her book The 6th Extinction: An Unnatural History, Elizabeth Kolbert reported that of all the carbon dioxide that man has released into the air so far, one-third has been absorbed by the oceans. He added that this corresponds to 150 billion tons. Unfortunately, this absorption has consequences; In fact, an acidification of the oceans is observed, characterized by a reduction in the pH of the waters due to the increase in the amount of dissolved CO2 that comes from the atmosphere.
Chain reaction illustration
Dissolved CO2 interacts with water molecules and carbonic acid is formed that will have consequences on marine fauna and flora: species such as starfish, urchins, oysters, reefs, etc. they are in danger. Indeed, they will not be able to manufacture their shells and skeletons because of the decrease in carbonate ions or aragonite. In addition, its protection will be less solid due to the corrosive effect of the water that will dissolve it.
Apart from the shells, the behavior can be damaged. One study showed the effect of acidification on squid development. Indeed, squid that were in a more acidic place had a slower development and were smaller than the average. In addition, the organs that allow them to orient themselves were affected as well.
Greenpeace reports that 25% of the ocean's species live on coral reefs. Acidification of the oceans could cause chain reactions. Some animals will not have food because pteropods or sea snails, important elements of the marine food chain, have their shells dissolving; or some will not have a shelter because of the destruction of the reefs. All that touches us; Apart from the lack of one type of food, it could have economic consequences: what will happen to the fishing industry, gastronomy? The oyster farmers are already suffering; in 2006 many oysters died on the west coast of the US and ocean acidification was considered the cause.
Experts reveal that the acidity of the oceans increased by 30% in 250 years: since the beginning of the industrial revolution, the pH has dropped from 8.2 to 8.1. That's worrying because the phenomenon is faster now compared to the same one that occurred 252 million years ago in the past and that resulted in the largest mass extinction on Earth (known as the great Permian extinction). How to fight against the acidification of the oceans? The reduction of greenhouse gas emissions is the key to our problems; It will contribute to the mitigation of global warming as well as the acidification of the oceans.