Warming, acidification, and lack of oxygen are creating conditions in the oceans that could lead to “a phase of extinction of marine species unprecedented in human history,” according to an article from the Environmental News Service.
A report from a panel of international marine experts warns that these stressors are causing degeneration “far faster than anyone has predicted.”
"The findings are shocking," said Dr. Alex Rogers, scientific director of the International Programme on the State of the Ocean. "As we considered the cumulative effect of what humankind does to the ocean, the implications became far worse than we had individually realized."
Although this article doesn’t mention the massive swarms of jellyfish that have been showing up worldwide, my suspicion is that this is a consequence of that degeneration.