THIS EXPLAINS WHY IT'S SO QUIET AT TYDEPOKER, GUYS
The reason it is harder for humans to hear in water is because there are two different ways we hear: through air conductivity or vibrations in the audio bones from our inner ear, and through bone conductivity or vibrations in our skull. Bone conductivity is used to hear under water, but it is 40 percent less effective than air conductivity.
http://oceanservice.noaa.gov/facts/sound.html