Mass extinction 183 million years ago offers dire warning for modern oceans

Earth has endured multiple mass extinctions during its existence—the Toarcian Oceanic Anoxic Event (T-OAE), for example, decimated the planet’s marine ecosystems. But according to a new study from international researchers at Caltech, George Mason University, the University of Naples, and elsewhere,Sexdolls kaufen the T-OAE’s destructive fallout over 300,000-to-500,00 years may pale in comparison to what humanity can accomplish in a fraction of the time.

Around 183 million years ago, cataclysmic volcanic activity in modern-day South Africa spewed roughly 20,500 gigatons of carbon dioxide into the atmosphere, increasing sea levels, water temperatures, and acidification in the process. The resulting deoxygenation (called anoxia) initiated a mass extinction of marine life that would take as long as half-a-million years to recover.Realistische Sexpuppen While researchers have long known about the T-OAE, they haven’t fully understood its true scope. This is particularly a problem when it comes to predicting how future anoxic ocean scenarios could affect the planet.

“Despite recognition of the T-OAE as a potential analog for future ocean deoxygenation,Vollbusige Sexpuppen current knowledge on the severity of global ocean anoxia is limited largely to studies of the trace element and isotopic composition of black shales, which are commonly affected by local processes,” the team explained in the abstract of their paper published on June 24 in Proceedings of the National Academy of Sciences. So to better comprehend the T-OAE’s dynamics, researchers turned to uranium isotopes for help.Japanische Sexpuppen

As an accompanying Caltech announcement explains, the amount of uranium isotopes in the ocean is directly related to anoxia levels. If you can measure uranium samples’ isotopic composition, then you can estimate seawater’s oxygen levels (or lack thereof). Although it’s impossible to directly sample water from the T-OAE, rocks like limestone offer records of the time thanks to their uranium levels.Neue Sexpuppen Uranium generally remains soluble in water when oceans are oxygen-rich, but precipitate and settle into the ocean floor during periods of anoxia. By examining how much uranium is in ocean sediment dated from the T-OAE, experts can estimate how bad things truly got during the extinction event.