Underwater photograph of a school of fish taken from the island of Saint Barthelemy.
©Marcel Moshe / Agence France-Presse
During the past 500 million years, some cataclysmic event led to the deaths of 75 to more than 90% of all species that arose on Earth, during mass extinctions. According to oceanographers Curtis Deutsch and Justin Penn, lessons from these disasters can be learned in the context of the biodiversity crisis, the fight against climate change and the conservation of marine species.
Atlantico: According to some researchers (oceanographers Curtis Deutsch and Justin Benn), Mass extinctions are currently occurring in our oceans. What is the reason for that?
Francois Sarano: Mass extinction, I don’t know. A radical erosion of diversity for sure. We are the actors, fishing and destroying coastal areas, pollution with all biocides has already weakened most species. Global warming will change all the leaves of marine life. why ? Because by heating the surface waters and increasing evaporation in some places, the density of the masses will change and the ocean currents will be completely modified. Water quality will change, as will marine circulation. However, most marine life is plankton, which are organisms dependent on currents and temperature. Almost all marine animals, even large fish, have a planktonic phase during their lifetime. So all the cards will be modified, but we have no idea what will happen. Mass extinction is one among many scenarios. Let’s not be arrogant. We ignore many things. There are hundreds of thousands of species that we know nothing about, not to mention the impact of hydrological changes on their interrelationships. What is certain is that the changes will be drastic. Species that cannot move, such as corals, will be most affected. But most of them will move and take advantage of the currents to colonize areas where they could not live before.
How can it still be stopped or slowed down?
If we want to change this, we must drastically reduce our energy consumption, and give up all our electronic devices. When I see bright ad screens showing up that brag about saving energy, I tell myself we’re on our heads. We must also drastically reduce greenhouse gas emissions…and I hear we’re going to turn to shale gas, which is the worst thing we can do against life. Change is inevitable, but it doesn’t deserve to be criminally irresponsible. It all depends on us, the consumers. For once, let us exercise our freedom of action: not to consume. If marine ecosystems are threatened, it is primarily because of our insatiable withdrawals. We eat a lot of fish. Above all, we use trawls that destroy entire ecosystems. Trawling is carried out even in protected areas. If we want to preserve marine life, we have to create real marine reserves, where nothing is taken. And because we don’t know exactly what will happen, we must change our behavior now.
Scientists are trying to understand what really happened under the sea during the year of the great ocean calm
250 million years ago, the Permian-Triassic extinction or the Permian extinction, according to some analyzes, killed 96% of marine species due to global warming. Are there lessons to be learned from our knowledge at the time about how to prevent this from happening again?
The Permian era, the confluence between the primary and secondary era. At that time, there were already significant changes and many species disappeared. But our knowledge is limited to the species in which we have fossils. The lesson is that it is not worth waiting for other studies. ? We can’t say we don’t know. We know what needs to change to give our children a livable world. So let’s act with complete responsibility/freedom. Let’s be sane adults.
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