your answer is a <em>habitat</em>
The red blood cells would look just fine or normal in the person who has drowned. Water wouldn't be lost because it wouldn't be attracted to the concentration of the salt water and the salt water would be too large to break the barriers.
Fish poop.
Tropical white beaches get their pearly white color from the excrement of fish far off of the coast which eat coral and other things that reside on the ocean floor. When they eat they swallow some sand into their mouths as well, and process it with the food they just ate. Their stomachs can't really digest the sand, tiny minute rocks essentially, and thus turn their color white. Or the rock forming the sand can be naturally pigmented a whitish tone as well.
