Reddit reviews Blueheart

Blueheart by Allison Sinclair is about a colony on a water world that is reaching a crisis point between the first settlers who were genetically altered to make living on a aquatic world easier, and the settlers who came after the colony was established and were never altered. There's a lot of tension between the two groups that could spark civil war.

It's got politics and economics, and is still pretty topical for some of its themes.