Photographer David Liittschwager did something very interesting recently. He took a few drops of seawater and zoomed in 25x. He then captured the image and posted it for the world to see.
This is what you swim in when you go to the beach.
Of course, this whole exercise is just for fun. It may seem a little creepy that you are floating in all that stuff, but the reality is that you would find similar results if you magnified anything 25x. Heck, if you did it to your cell phone, you would notice something far more horrific than what is in that droplet of seawater.
Still, it is fun to know what exactly seawater is comprised of.
Source: Viral Nova