Colour and Light in the Bloodstream

By using shading maps I'm now trying to create a graphic art style in my Maya sets. Before did that I added a polygon plane to be the blood surface, so it can be coloured separately.

 I tested the image plane behind the set to see what the change may look once rendered.

 I feel the shading maps have worked well in bringing out the silhouettes of the trees. This render resembles a silk screen painting, which is the effect I want.

 I added a directional light, which seems to show up boldly on the next render, but when I removed the light and added the backdrop with the shading maps applied, it created a reflective water effect. I have no idea what caused this but some how the image plane  made the water surface reflect the land and the trees. I really like this effect but I'd rather not render this scene with an image plane. I'd rather add that in After Effects. So if anyone has any ideas of how to get this reflective effect with out the image plane, PLEASE TELL ME.