So I was playing Minecraft java and I found a strange glitch that caused kelp to create water source blocks. I made a new world (Upped the tick speed so it would be shorter) and demonstrated the weird glitch in the video below.  (Uploaded to YouTube due to file size limit.)

https://youtu.be/k8Dvs0LlvdE

Steps to reproduce

1. Place 1 bucket of water and let it flow.
2. Dig down a certain amount of blocks under the flowing water. (2 for this example)
3. Place kelp and wait for it to grow.
4. Once grown, break kelp.
5. Use buckets to get 4 water from 1 source block.