okinawa 4

This time I'm going to talk about the oceans is Okinawa.
Although the oceans in Okinawa are beautiful, the number of coral reefs have decreased recently.
It is said that many many years ago, the main island in Okinawa was not bigger than it is now.
The island used to be surrounded by a huge coral reefs.
Only the northern part of the island was a big hill, and other parts of Okinawa ( middle and south ) were in the Ocean and had coral reefs.
Then, the sea level changed and those coral reefs became grounds, which means that middle and south part of Okinawa is made of dead coral reefs and mud in the bottom of the ocean.
So I think that in the old times, the ocean in Okinawa could have been soooo beautiful.
Nowadays, we face global warming, and the number of coral reefs has decreased, even in Kerama islands, which are well known for its beauty of coral reefs.