disappearing resources

[Bralmicaan]

the game had 4 sources of uranium. none in any AI teritory.. I have the satelite up so I can see all the terain. searching for the resource finds no others. but suddenly 1 of the 4 is gone. and perhaps just as odd another AI player suddenly seems to have 3 to trade with. that whilst there are none in his teritory?

how can this be? -> this could be caused by scientific progress I think there is one which gives you 3 per turn and a giant death robot in your capital city.

however still missing a uranium deposit

 

[Pfeffersack]

Perhaps rising sea level has drowned a tile with a deposit permanently? Not sure if in this case the search still brings the ressource up.