Last week of February, last issue before this blogs one year anniversary. Over the last few months this series has really metamorphosis into something I’m proud of, much like the Tiger Swallowtail from last week, and it’s thanks to the support of you, the reader. And that includes readers like @transcendence who nominated the first of our ‘gelatinous trio’ (others to be release in March) for this weeks issue. Hope you guys enjoy.
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Issue #56 - Immortal Jellyfish
Kingdom – Animalia
Phylum – Cindara
Class – Hydrazoa
Order – Anthoacetteta
Family – Oceaniidae
Genus – Turritopsis
Species – dohrnii
Related Species - The family Oceaniidae contains around fifty species spread across ten geneses (1)
Range
One Step towards Immortality
The Immortal Jellyfish adheres to the classic jellyfish body plan, with a bell at one end and trailing tentacles at the other. At only half a centimetre in length and width, the adult medusa is part of the zoo plankton, and is usually found in the top two hundred meters of the water column. Like its relatives, the internal organs of the Immortal Jellyfish are highly simple, or in some cases non-existent, and in the case of the aforementioned species, the only visible organ is the bright red stomach (2).
When hunting the jellyfish trawls through the plankton, catching prey with its trailing tentacles, which are lined with stinging cells to immobilize its target, before drawing them back to the stomach in the bell. Despite its name, the Immortal Jellyfish is preyed on by larger jellyfish and other larger plankton feeders. The term immortal refers to a process called transdifferentiation, the process of resetting the bodies’ mature cells back into unmodified stem cells. And while several animals use this process to grow or replace new organs, the only animal that completely regenerates this way is the Immortal Jellyfish, and potentially other members of the genus Turritopsis (3).
The environmental pressures that cause the Immortal Jellyfish to revert, from a free swimming medusa to a stationary polyp, are linked to food shortage, disease and physical injury. These polyps form colonies and eventually bud into adult medusa, with the original animal essentially bypassing death, capable of reproducing in the standard jellyfish fashion or returning back to their polyp form when injured. That said, all studies of transdifferentiation in the Immortal Jellyfish have taken place in laboratory conditions, and hasn’t been observed occurring in the wild.
Ecology 101: A Guide to Environmental Mechanics - #5 Jellyfish Blooms
Despite being biologically simple Jellyfish are some of the most successful animal groups on the planet. And while large swarms of species such as the Moon Jellyfish (Aurellia aurita) are well documented, many species have started appearing in large ‘blooms’. While this is due in part to the constant stream of eggs (or sperm) released into the ocean by the free swimming adult medusa, there is more to these occurrences then this going on.
While such blooms may be initially trivial, such explosions in population have severe economic and ecological effects. Since jellyfish are indiscriminate feeders, they will take small fish as readily as zooplankton as well as other jellyfish. In addition to reducing vital fish stocks, sheer volume of individuals can cause damage to boats as well as causing human fatalities (4). Such blooms are possible due to a combination of global warming, depletion of predators and the creation of more anchor points for juvenile polyps. And while jellyfish are largely reliant on currents to spread themselves around the world, large numbers now hitch rides in the ballast of ships, often spreading to oceans where they have no natural predators.
At current there is no solution to reduce jellyfish numbers, and at current there is no sign that these blooms are decreasing in size or frequency. Few species reliably feed on large numbers of jellyfish, and those that do such as the Leatherback Turtle (Dermochelys coriacea) and Sunfish (Mola mola) are highly endangered, mostly due to human interaction. As such it’s theorised that humanity may have to adapt to living in a world were ‘the Jellyfish Invasion’ is the norm and not an unusual occurrence as it currently is.
Bibliography
1 - www.arkive.org
2 - Kramp, P. L. (1961). "Synopsis of the medusae of the world". Journal of the Marine Biological Association of the United Kingdom40: 1–469
3 - M. P. Miglietta, S. Piraino, S. Kubota, P. Schuchert (2007). "Species in the genus Turritopsis (Cnidaria, Hydrozoa): a molecular evaluation". Journal of Zoological Systematics and Evolutionary Research45 (1): 11–19
4 - http://qz.com/133251/jellyfish-are-taking-over-the-seas-and-it-might-be-too-late-to-stop-them/
Picture References
1 - http://2.bp.blogspot.com/-_aGOgV5JgFQ/UTc1TqnuqRI/AAAAAAAABgE/_IySfqjG_5Q/s1600/The+Immortal+Jellyfish.png
2 - http://www.discoverlife.org/mp/20m?map=Turritopsis+nutricula
3 - http://www.immortal-jellyfish.com/images/immortal_jellyfish.png
4 - https://qzprod.files.wordpress.com/2013/10/jellyfish-map-featured.png?w=940
And as we process that terrifying future where the Immortal Jellyfish overlord rules the oceans, we must think onto another animal, in this case the king of the Kaiju himself. But until then critic, comment and check out past issues in Impurest’s Bestiary
Many Thanks
Impurest Cheese
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