Subject: Does land use effect the organisms in a river?

I am an A-level student studying organisms in a river in order to write a 
piece of coursework for my final grade.  i am studying a minor industrial 
area, farming (where fertiliser has been used), housing and a control 
area.  I understand that eutrophication will have an effect on the 
organisms through lack of oxygen, but what will these effects be?

Re: Does land use effect the organisms in a river?