Reading material for a youngster regarding aquatic ecosystems

I was hoping someone here might be able to help.
I'm looking for a book or some other such educational material for children roughly 9-12 years old.
Basics on freshwater North American aquatic ecosystems would be great.
Any leads great or small, above or below the age suggested would be very much appreciated.

Project WET has a few. I saw a children's storybook involving a diving beetle a few weeks ago here at the office; I'll try to dig it up and give you its title.

Thanks Nathan. I like some of those books and I think they are more activity oriented and better suited for the younger than 9~12 group and a great find. Looks like a I'll get a couple for my daughter.
It's strangely difficult to determine if a book is suitable for a combination of real learning and the age group I'm interested in.
I guess I should mention that I believe many in the 9~12 age group welcome books without activities and photos on every page. They seem proud they are capable of reading chapter books. Now don't get me wrong, a picture says a thousand words but a picture to fill a page is not a picture to teach a child. Gosh I'm picky!

I agree, those books are not really suitable for your stated age bracket. I got a kick out of the Golden Guide to pond life at that age. It's mostly pictures of organisms with short pieces of info, but also contains a pretty good short synopsis of pond ecology at the beginning. If I recall right, things like food webs, the water cycle, and succession are explored. It isn't aimed specifically at kids, but is written in a very accessible way. http://www.amazon.co...89927461&sr=1-5

I agree, the "Pond Life" book is great for that age group. In fact, I think it's great for any age group that is new to aquatic ecology and can read at a basic level. Even adults find it interesting. It's a book that will last the kid a long time.

That looks pretty good! I searched like heck via Amazon and didn't manage to find that! Thanks Nathan.