Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Permian–Triassic extinction event:

"

If it continues to rise, the consequence could be another bio-calcification crisis, as seems to have occurred in the fossil record, which would have disastrous consequences for modern marine ecosystems.[citation needed]