I can't remember what exact flavor of marine scientist he was, so that's why I used a vague title, but he suggested that we not break up our glass, or crush our cans, because when they are whole many marine creatures can use them for habitat on the ocean floor (until the glass or cans biodegrade).

So we would save them in a bucket and then have a "sinking session." By that I mean that we would fill each bottle/can with seawater before dropping it over the side. We didn't want them to float long enough to get near shore anywhere (and of course we were doing this in deep water, so the glass/cans would be waaaay down at the bottom when they sank.

CCA-Boater