Biodiversity The Jelly Fish Case

Earths biodiversity includes variety of organisms that made our world really colorful and blissful to live on. Among these rich biodiversity are the marine organisms living underwater. In order to know more about a particular marine organism-how they really look like and how they can be of great importance to our environment, I visited the Audubon Aquarium of the Americas in New Orleans, Louisiana. At the Aquarium, I am very amazed to the different sea creatures that were living and breathing as if they were in their natural habitat.

With the intention of relating what I learned in the class, I focused my attention to a particular type of sea creature-the jellyfish. I eventually knew the specific type of jellyfish I am observing. I actually observed three different jellyfish comb jellies, Atlantic moon jellyfish and the Northern sea nettle.
All of the three jellyfish can be praised for their colorful appearance or transparent look with colorful pigmentation and their gradual slow motion in the water. They appeared so intricate but undeniably beautiful. The variation in number of tentacles and the position of the mouth of each type of jellyfish was also observed in the aquarium. For example, the comb jellies appear to have two tentacles with eight comb rows which can actually be seen in the water. On the other hand, the moon jellyfish can be distinguishable due to its unique spots and streaks.

Comb Jellies
Comb jellies is a small phylum of marine animals called Ctenophora which contains about 100-150 species. Having the ability to produce blue and green light, Ctenophora appears to be among the beautiful species undersea. In comparison with the cnidarians, they also continue to exist without hard skeletal parts and teeth.

Under the Domain Eukaryota, Kingdom,Animalia, and Subkingdom Eumetazoa, Ctenophoras most undeniable body feature is its comb rows. Highly observable, comb rows follow a wave pattern that moves from the aboral   to the oral end. The movement of a comb prompts the next comb to make its own stroke, thus, making a series of strokes that lead to the formation of the wave-like movement of the comb jellies. Unlike the cnidarian which exhibits a stop-and-go motion, ctenophora follow a smooth motion (Campbell, Neil et al., p. 54)

Nearly all the species of comb jellies favor living in warmer water and in tropical areas. Almost all ctenophora live deep down the sea or found around the poles. Some species also reach up to a depth of 2000 to 3000 meters.

Body Characteristics and Features
A sense organ present at the end opposite the mouth is one of the key features of the ctenophora. It holds a statolith that dictates the orientation of the comb jelly. Like cnidarians, it is at its tissue level of organization with its body exterior wrapped with thin ectoderm. This ectoderm enters the mouth and lines the pharynx. In digestion, the ectoderm serves as the agent of the extracellular digestion occurring in the stomach or stomodaeum.

Ctenophores body is consists of Epidermis, Gastrodermis and Mesoglea which is actually layers of cells. The eight sets of cilia present in its body is use by the organisms to swim and to maintain its original water orientation. They are also considered carnivorous since the classes of Ctenophore, Tentaculata and Nuda both catch fish or other creatures in the sea and feeds same ctenophores exclusively. The comb jellies that I observed possessed two main tentacles with sub-tentacles on its side. This proves that the ctenophore that I have watched is the Tantaculata class. Nuda is the other class of Ctenophore which has very large mouth present in their bell-shaped bodies (Campbell, Neil et al., p.56). This class can eat organisms more than half their size and contains half of the total number of Ctenophores species.

Distinct from Cnidarians, ctenophores have no polyp phase. Almost all ctenophores are hermaphrodites (possesses both the male and female reproductive organ) which in turn produces both sperm and egg cells at the same time. The gonads release the egg and sperm cells in the water through the mouth. External fertilization happens to the egg which in turn develops it to a tiny larva. This larva develops cydippid-like paired tentacles which lessen its number through the course of the life span.

Atlantic Moon Jellyfish
Atlantic moon jellyfish is a specific kind of moon jellyfish that can be found in the Atlantic Ocean. Moon jellyfish scientifically known as Aurelia Aurita is a Cnidarian species under the Ulmaridae Family and Genus Aurelia. The common name moon jelly can be accounted to the moon shaped-gonads at the center of the bell. They can be mostly found in warm and tropical waters near coastlines- withstanding temperatures as low as 6 degree Celsius and as high as 31 degree Celsius. Locally found in Virginias water, they can also be found in many oceans in the world. Moon jellyfish are also present in the Pacific Ocean- from Alaska to Southern California (Coleman, N., p. 69)

Known for its fine and beautiful coloration, moon jellyfish sizes from 5 up to 40 cm in diameter. How they react in the environment depends on external conditions like availability of food. Also observable in the moon jellyfish is its four violet or pink crescent shaped gonads located in its underside. I can also recognize the thickness of the bell of the moon jellyfish in the middle which tends to appear thinner across its edges. The limitation on its movement only allows them to be near the surface of the water. Upon its stay near the surface of the water, its tentacles spread throughout the area, thus, maintaining the largest possible area for the catchment of food.

As we learned in our discussions in the class, Cnidarians have two main stages in life the polyp stage and the medusa stage. Like all cnidarians, moon jellyfish also follow the same life cycle. Aurelia auritas polyp stage or asexual reproduction can be described as a mature polyp reproduce through budding forming. This process develops and in time produces ephyra or small medusae through budding. Upon the maturity of the said medusae, it reproduces sexually allowing a zygote to be formed out of the egg and sperm cells. The next stage will be planula (larva) which in turn leaves the adult medusae.

Considered as carnivorous, moon jellys primary foods include small planknton organisms like crustaceans, nematodes, copepods, protozoans and diatoms. They also eat small ctenophores and hydromedusae. The sting cells present in their bodies prevent the prey from being active allowing the moon jelly to entangle them in mucus. Moreover, the food is passed through the mouth, along the eight canals inside the body. This brings the food directly to the stomach where it is digested by the enzymes.  

Northern Sea Nettle
The northern sea nettle also known as Japanese sea nettle (Chrysaora melanaster) is a species of jellyfish local to eastern Pacific Ocean. Sometimes referred to as Pacific Sea nettle, northern sea nettle is a cnidarian under the class Scypozoa and Pelagiidae family. Common near surface water, northern sea nettle have a bell ranging from 25-30 cm in size and possesses long tentacles which ranges from 3-6 meters. Unlike other cnidarians, the northern sea nettle has no respiratory organs.

As also observed in the aquarium, the northern sea nettle is transparent and contains red-brown stripes and white dots. The sting present in the body is rated from moderate to severe. Causing discomfort and irritation to any organism, the sea nettles sting cannot cause human death.

Chrysaora melanaster as a carnivorous organism uses its mouth as the main hole for digestion. Located at the center of one end of the body, the mouth contains a gastrovascular cavity that is chiefly used for digestion. Northern sea nettle immobilizes their prey through the use of their stinging tentacles.  The common prey ranges from ctenophores, jellies, and zooplankton.

Jellyfish like every other organism gives our environment the benefit of balancing the life underwater. Aside from that, it gave the underwater the colorful place for exploration that in turn will make us appreciate the blessings our Creator gave us.


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