Not to detract from the man's project (which I think is cool), but every little piece of garbage in the ocean does add up. Oceanographers have mapped garbage patches in each of the oceans, e.g.:
The Great Pacific Garbage Patch (http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch) is a real problem. Estimates put its size between 270,000 sq miles 5,800,000 sq miles of floating trash, most of which is plastic. It pollutes the water, kills marine life, and introduces toxins into the food chain which can end up on your dinner plate.
Saying 2000 bottles is not a big deal in the grand scheme of things is shortsighted and irresponsible. Millions of tons of garbage doesn't appear in the ocean for no reason. It exists because everyone thinks to themselves "hey, the ocean is a really big place... what harm does a few bottles really have?" The problem is only getting worse, and after all.. we haven't had plastics for that long.
There's no justification for throwing plastic bottles in the ocean. It doesn't improve the environment in any way, but it currently negatively affects hundreds of species.
A one-off deposit of 2000 bottles has a negligible impact on the Patch. To tackle that, we need to fundamentally re-think a lot of the ways we conduct ourselves.
Perhaps a better, and more rational argument, is that we should care more about the oil being burned around the world, and not less about the amount of trash being thrown into the ocean.
http://www.wired.com/wiredscience/2010/08/atlantic-plastic/