Comment from where I got this:

Hey I live there, so a few things: 1. The picture is wrong, that's nowhere in Malta. 2. The actual salt pans ARE Roman. 3. Salt pans are designed to dip underwater at high tide, so they've been coming in and out of the sea since they were built lol. Climate change has altered the exact times when they are above sea level though, and very drastic climate change will mean that they will eventually remain underwater indefinitely.

Edit from @Skua's comment below, fact checking this fact check:

Not sure about that comment, since those pools really are at Sliema in Malta https://www.google.com/maps/place/Roman+baths/@35.9165797,14.5036778,73m/data=!3m1!1e3!4m14!1m7!3m6!1s0x130e453d17183bff:0x2f6d720c7897d7de!2sFond+Għadir+Beach!8m2!3d35.9155994!4d14.5047453!16s%2Fg%2F11c0r4z3k8!3m5!1s0x130e453d997aaaab:0x2aaf0dc1de0d774e!8m2!3d35.9165157!4d14.5038595!16s%2Fg%2F11sskr6_j9?entry=ttu

But according to the local council’s facebook page when it shared this photo (they didn’t take the photo), they were built during the British period https://www.facebook.com/story.php/?story_fbid=878845397617697&id=100064767334211&paipv=0&eav=AfYRGKX34jrDJ5AuxuFU5SHiG8WiLpg42yMEYXZDkFKFtbbZPeS2GXwntwik1u1PZkc&_rdr