system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: Why do drowned bodies sink and then float?
gpt
As someone who has recovered bodies from waterways... The bodies are almost neutral bouyancy at time of death, but then take water in and loose air from those balloons we call lungs after death causing the remains to sink.

Go float in a pool, and exhale. See how fast you sink without that air in your lungs.

The resurfacing occurs due to mostly natural bacterial flora inside your body beginning the decomposition process. This produces gasses inside the carcass, causing swelling and bloating. This eventually acts just like the air in your lungs and the body resurfaces. Actually much more boyant.