The funds are available as a convenience... If the check you deposited doesn't clear, the funds are taken back... I JUST had this happen with BofA with painful consequences, as I had spent the deposit (which ended up as an overdraft on my account because the deposit was taken back).

Only problems I see here are that: 1. Melt water is fresh (and therefore less dense than the seawater is would be displacing) 2. The Artic Ocean (and all the oceans once you go down enough) are already pretty close to that temp (~3C).