Sea under the sea under the sea

The year is 2082. Most of the planet is covered with water, and the composition of marine fauna has changed dramatically. Humanity has about 500 million people, most living where mountains used to be. You are in the Carpathian port. A team of researchers found an anomaly in the Black Sea. The signal shows that part of the seabed has begun to rise. Everything indicates that a new island has f…