 okay here's a bit of soil chemistry so I'm holding this piece of mud that I just took off from the surface of the soil and it's interesting because you see a brownish layer on top here a thin one it's about maybe extends about two three millimeters deep into the soil on top of that is actually a bit more greenish yeah and then underneath of that we have this dark gray blackish soil and that's basically what's happened happening in a flooded soil it's what we call a chemical reaction which is actually driven by microbial processes reducing the iron compounds from iron II iron III oxides and hydroxides which have a reddish color into iron II compounds which have a grayish color so what we have up here is basically a layer where the oxygen jet still comes in from the water that we put on and though that always stays oxidized and underneath of that we have this highly anaerobic reduced soil in which the roots are but this is also up here very biologically active layer which is why it's greenish on top so you've got algae living on top doing nitrogen fixation and all kind of things