Those who live in the Brightwaters are the soft ones. They are the closest to the sun, which is not a friend to all that resides in the blessed waters, and some of them even choose to live in the dead water (freshwater). Clearly they may have a little too much in common with the dry-breathers...and you know some of them even trust that kind of magic? The one born of unnatural studies?? Clearly they did not learn their history as they should, and therefore should not be trusted.
Conversely, those on the Surface must be very brave to deal with those on land, because they are very strange and live lives that are so different from ours. They know about exotic fashions and customs and might even have a piece of something made on land. They are the most likely to have and make use of shipwrecks (which are considered the common property of anyone who finds them until a purpose has been established), and magical items from the dry lands are fairly easy to acquire in this area. Or at least ones that make sense under the waves. Have you heard of that truly ridiculous one?? A pouch, that spouts water of all things! Why would you ever choose to be far enough away from water to not have it when you need it? It simply doesn't make sense!