Thank-you everyone for the compliments! The problem with the population is sheer idiocy on my behalf, as the population bounding box only seems to cover the right portion of the screen. I'd love to render it in a higher resolution, but I don't yet have the deep version (an upgrade that i'm planning to get, since i'm working on a project that will probably need renders at roughly 2048x2048 size, but the purchase will have to wait a bit), although this image was cropped (the sand by the lake - why did I put sand by a lake!? - didn't work with the rest of the scene) , so i could re-render and show a bit more sky, or something.
The seaweed was an accident really, and it's only convincing in the darkness that the scene is in (it is a sunset scene quite similar to the one posted above). I put too much displacement on a small fakestone layer, and added a water shader to make it look wet. It looks kind of like wrackspurt (I think, I'm not so good with seaweed varieties) but I'm sure the fractals could be tweaked to make it look better.
