Europe, Italy, Campania, Amalfi Coast, small bay at Conca dei Marini
Name in Italian:
Grotta dello Smeraldo
> 45 m
Small but interesting is Grotta dello Smeraldo - Emerald Grotto - partly submerged cave in Amalfi Coast, Italy. Sunlight enters the cave indirectly - through the seawater and most of the visible spectrum is absorbed. Thus the water in one corner of the cave shines in a beautiful emerald green - blue color.
One more blue grotto
Most likely some locals knew about this cave in earlier times - but wider society learned about it in 1932, when local fisherman Luigi Buoncore entered the cave and told about the beauty of the emerald light.
Back in those times cave was accessible only by diving 7 m deep under the cliffs. Today it has been turned into tourist attraction and is available with much comfort - by an elevator (but also for free - by a ladder). As the elevator descends, tourists can enter the boats and take a tour around the cave.
The development of tourist infrastructure (and some extra possibilities for cash collection) have taken away much of the natural beauty in the cave - mainly psychologically, especially if the guides are stubbornely telling nonsense about the cave. Amalfi Coast is that beautiful that one cave with emerald light in the corner does not seem to add anything of value. Nevertheless this cave is an interesting landmark which can tell its story about the local natural history - if one cares to read it.
Geology and biology
Cave room is 45 by 32 m large, ceiling rises up to 24 m above the water. This large cavity has been formed by tectonic (bradyseism) and karst processes in the times when this rock was rised above the sea level, some 5 - 6 thousand years ago.
When the cave was above the water level, stalactites and stalagmites formed in it. Some stalactites grew until they met their respective stalagmites and formed up to 10 m tall columns.
Now these beautiful cave formations are partly inundated - bradyseism descended and sea water entered the cave.
Rare sea anemone (Anemonactis mazeli) lives in the cave and has adapted to the lack of light. The very rare leopard-spotted goby (Gobius forsteri) has also been spotted here.
Cave is not explored yet - there are two underwater passages in the north wall of the cave, which are waiting for their explorers.
Italian television and Sorento Diver's Club had a weird idea back in 1956 - to dive in the Emerald Cave and to place there a nativity scene made from clay figurines. Now this has turned into a tradition - divers are coming here with a procession every Christmas. They dive and place flowers at the statue of Jesus Christ. This has greatly helped the club to get some more attention and new members.