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Tuesday, February 9, 2010

Lagoon Jellyfish

Lagoon jellyfish (Mastigia papau) is another one of the more interesting species of Jellyfish. If you have heard about the Golden Mastiga at the Jellyfish Lake, you may be interested to know that they are actually descendants of the Lagoon jellyfish and over the years have adapted to the conditions of the marine lake. In nature, lagoon jellyfish are found in bays, harbors and lagoons in temperate waters mostly around the Pacific Ocean.

Just like the upside down jellyfish, the lagoon jellyfish also maintains a symbiotic relationship with unicellular algae called zooxanthellae. These algae are photosynthetic and use sunlight to produce carbon rich nutrition. The lagoon jellyfish then absorbs the nutritional leftovers from this process of photosynthesis. Lagoon jellyfish depend on this source of food in large measure, although it does not provide them with all the nutrition they need, and so the lagoon jellyfish also feed on planktons and zooplanktons.

Unlike the upside down jellyfish, the lagoon jellyfish do not keep their bellies exposed to the sun. Instead they undertake daily migration. During the day, they migrate eastwards to take the highest advantage of available sunlight. By noon, they start migrating westwards and stay in the west until day break. This fascinating process allows them maximum exposure to sunlight and higher quantities of algae waste matter. Their dependence on the sunlight also ensures that they are mostly very close to the surface of the water, unlike the upside down jellyfish that tend to settle on the surface of the water bed. Mostly at night, jellyfish sink towards the bottom to catch prey for feeding. Like most jellyfish, the lagoon jellyfish is also capable of vertical motion and is able to sink downwards or thrusting itself upwards by forcing water in and out of its body.

Unlike most species of jellyfish, the lagoon jellyfish does not have thing long extending tentacles. Instead the lagoon jellyfish only has oral arms. However, these orals arms are not like the joined arms of the cannonball jellyfish, but are more like thick spider legs. What is interesting is that these oral arms are not meant for transporting food to the mouth. Instead they each have a tiny mouth themselves! Considering that the size of their mouth is extremely small, they can only feed on microscopic plankton and zooplankton. However, since they also receive nutrition from the waste matter of the photosynthetic process of the algae, planktons provide enough additional nourishment.

Even though the lagoon jellyfish does not have tentacles, the oral arms are equipped with venom filled nematocysts for defending the jellyfish and for procuring its food. These nematocysts are controlled by nerve endings, and whenever any pressure is applied, the nematocysts inject powerful venom into their victim or prey. The stings of the lagoon jellyfish can be quite painful for humans. Lagoon jellyfish have very powerful venom that can cause a variety of effects on the human body. Symptons include rashes, severe itch, nausea and vomiting. However, no stings of the lagoon jellyfish have ever been considered fatal.

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