What makes you think the top shots are in AdobeRGB colour space?
The only reason I ask is because they appear on the monitor to have clipped channels and look awful, as they do if I import them into CS2 where my working space id AdobeRGB. However, if I assign sRGB to them in CS2 they suddenly acquire all that detail back and look correctly saturated.
The top of each of the pairs are the Adobe98 images.
We're having a similar discussion in another thread about the same series of images. Smugmug claims, in their help section, to automatically convert Adobe98 to sRGB; that might explain why there is no indication of the color profile in the file. I assure you that nothing is clipped in either the sRGB or Adobe98 images. I use NX to create tif files in Adobe98 and then resized and converted the images to jpg sRGB.
These sRGB images came out dull; quite disappointing. I took the sRGB images into Photoshop and converted to Adobe98 and saved them in a different location and re-uploaded them to another gallery. As I mentioned above Smugmug automatically converts them to sRGB.
I'm at a loss to explain the difference in the images since they are both apparently sRGB images. An explanation might be the software they use to convert the profiles.