From Live Science:
Mass extinctions that wiped entire species off the face of the Earth in a relative blink of the eye are often blamed on catastrophic occurrences, such as an asteroid crash or large volcanic eruption. But a new hypothesis points to a different culprit: lowly algae.
In the past 540 million years, five massive extinctions are thought to have killed off, in each case, some 50 percent to 90 percent of animal species. A new study suggests that toxins from algae played a major role in all five extinctions, including the most recent and most well-known – the death of the dinosaurs 65 million years ago. The idea was presented at the annual Geological Society of America meeting Oct. 19.
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