[orgo814]

I was given a pourbaix diagram for uranium and was asked the following:
a) If the lake is well aerated and not polluted, in what form will the uranium be found? Will it be present in solution or found in the sludge at the bottom of the lake?
b) If the lake is well aerated but is highly contaminated with acid rain (pH = 3), in what form will the uranium be found? Will it be present in solution or found in the sludge at the bottom of the lake?
c) Suppose some metallic uranium is dropped into this lake (with pH = 3), but it falls to the bottom of the lake, where oxygen is absent and reducing impurities (from decaying organic matter) are present. Will it remain as elemental uranium? If not, write a balanced chemical reaction for what will happen and describe its vigor

I am having trouble uploading a picture of the specific pourbaix diagram and the ones I found online are differerent but since these questions can apply to any pourbaix diagram I'm just trying to get the theory down and can hopefully figure it out based on that. My biggest question is the first one. Given a pourbaix diagram with all these different forms of uranium at different pHs, how do I know which form will be found if the lake is well aerated and not polluted? I know how to determine if it will be present in solution or found in the sludge. For part B, I would just start from whatever form I got in part A and go horizontally to a pH of 3 to determine the form after acid rain. For part C, elemental uranium is being dropped into a lake towards the bottom where it is surrounded by many reducing agents. Would it just remain as elemental uranium since it really is already reduced? Help would be appreciated especially on part A.