Most people do not like jellyfish, fortunately, they appear on the coast only from time to time. But imagine a place where they exist constantly and in large numbers. Presented? There is such a place! This is Lake Medusa in Palau.
Rocky islands
The Republic of Palau is located in the Pacific Ocean, approximately 800 kilometers from the Philippines. It is completely located on the islands and impresses with its nature. One of its archipelagos - the Rocky Islands - was even called the "underwater wonder of the world." Its coastal waters are inhabited by more than a thousand species of fish and marine mammals, many of which are rare.
It is not surprising that the "monastery of jellyfish" is located here. A lake with inhabitants unusual for such reservoirs appeared 12 thousand years ago. Now it is inhabited by several million jellyfish. The number of tourists arriving to look at them, also does not lag behind this figure. Due to this, snorkeling is developing here - surface swimming with a tube and glasses, with which you can watch the “jelly-like” for hours.
Where is Lake Medusa located? It is located in the eastern part of the coral island of Ayl-Malk. The lake is not too big, but elongated. In the widest place, the reservoir reaches 160 meters, in the longest - 460 meters. Its depth does not exceed 50 meters.
Features of Lake Medusa in Palau
There are about ten lakes like this on the island, but it is the largest. It is interesting not only for its inhabitants. So, the reservoir belongs to meromectic or two-layer lakes. Its surface and deep waters differ and practically do not mix with each other.
The upper layer of Lake Medusa in Palau is saturated with oxygen. It extends to a depth of 15 meters. Within it, most living organisms live, and atmospheric precipitation and flowing water also accumulate. The lower layer is devoid of oxygen, but it contains hydrogen sulfide, phosphates and ammonia. Due to the harm of such water to humans, diving is prohibited here. The upper level of the layer is inhabited by bacteria.
The lake formed in the natural depression of the island, which appeared as a result of the movement of the earth's crust. It is not completely cut off from the "big water"; it connects to the ocean through holes and cracks in limestone rocks.
Lake inhabitants
How jellyfish ended up in the lake is not exactly known. Most likely, young individuals came here along with water passing through the tunnels of rocks. According to another version, they have been living in the pond since its inception: after lowering the sea level, part of the water, along with its “population”, remained on the island, forming lakes.
Here, under fairly favorable conditions and the absence of natural enemies, jellyfish increased their numbers by several thousand times. Now the lake is just teeming with them. Two main species that live in it: golden jellyfish and moon. In addition to them, several species of fish and crustaceans inhabit the pond.
The way of life of golden jellyfish is closely related to the green algae that settle inside them. Organisms "concluded" a kind of contract, providing each other with useful substances. Algae needs light, so during the day, jellyfish move after the sun, describing circles around the lake. At night, they descend into the lower layers to get saturated with nitrogen.
Jellyfish life
The accepted names of jellyfish species living in the lake are only conditional. So, the golden jellyfish most likely refers to Mastigias papua, and the lunar jellyfish - to aurelia (Aurelia aurita). It is difficult to classify local inhabitants, because they have significant differences with related species living in the open sea off the coast of the islands.
Despite the small connection with the ocean, Lake Medusa in Palau is quite isolated. This could not but affect the lives of its inhabitants. Scientists suggest that a long separate existence contributed to some internal and external changes, as a result of which separate subspecies of jellyfish were formed.
Both the golden jellyfish and the lunar jellyfish belong to the class of scyphoid or creeping. As a rule, on their tentacles there are special cells that allow them to sting the enemy. Lonely and cloudless existence on the island contributed to the death of these cells.
