this is the members' tanks forum. you should post this in "new reefkeepers".
the green is algae, from what i imagine is a brand new tank, going through normal cycles. the black i'm not sure of. i'm betting on just some of the colorful stuff that you purchased it with, dying off. don't be alarmed. if it is infact a new tank, all that stuff that turned black will color back up in due time.
how about more information- how old is the tank, when did you add the rock, what are your water parameters...actually, even a picture would be a big help.