Wednesday, September 10, 2014

Æeolian Jellyfish

Æeolian Jellyfish, linocut with chine collé and glow-in-the dark in, 18 cm x 18 cm, by Ele Willoughby, 2014
This is a whimsical mini lino block print of the Æeolian Jellyfish, a widely unknown, and quite possibly, completely imaginary creature. Unlike other jellies, the Aeolian Jellyfish floats in the upper ocean of air, which blankets our planet.

The printed area is only 10 cm (3.9 inches) squared. The jellies have collaged or chine collé fine translucent white Japanese paper with visible fibres. The jellies are printed in UV-activated glow-in-the-dark ink. If exposed to ultraviolet light, including direct sunlight, the jellies glow. Each sheet is 18 cm (7.1 inches) squared and printed on white Japanese kozo (or mulberry) paper. There are 15 prints in this first edition.

The Aeolian jellyfish (Æolia noctiluca) looks much like its sea-borne cousin Pelagia noctiluca (where "Pelagia" means of the sea, "nocti-" refers to night and "luca" to light). Similarly "Æolia" and Aeolian come from the Greek Æolus, the keeper of the winds, and refers to its air- or wind-borne nature. Also, both jellies are bioluminescent. That is, they have the ability to glow in the dark. There are some important differences between the two, including, of course, habitat. While both animals have radial symmetry, the Pelagia noctiluca has a single body cavity, called the gastrovascular cavity. In contrast, the Aeolian jellyfish has both an outer gastrovascular cavity and an inner air bladder. This latter organ performs analogously to the swim bladder found in some variety of fish (though more closely related to the swim bladder found in Siphonophore colonies like the Portuguese man o' war). It is essentially an enclosed, impermeable, gas balloon, which can expand and contract to allow the Aeolian jellyfish to rise or fall in the air column by adjusting its shape such that the pressure in the air bladder matches that of ambient pressure. The Aeolian jellyfish also has a special adaptation to evade predators like birds; it can rapidly metabolize any food to produce a flash of heat in the gastrovascular cavity wall, lining the swim bladder. This allows the trapped air balloon to be heated, causing it to rapidly expand and the Aeolian jellyfish to rise. To move laterally, the Aeolian jellyfish employs its tentacles to ride the winds.
Æeolian Jellyfish, glowing in the dark

As you might expect for a bioluminescent animal, the Aeolian jellyfish is noctunal. During the day the jelly passive rises as it warms in the sun and its air bladder heats and expands. Thus it spends the heat of the day in the stratosphere, out of reach of predators. As temperature falls at sunset, so does the Aeolian jellyfish, disguised as a twinkling star to the flying insects who are its prey. Hence, while lulled to complacency by this lovely light display, it's death from above for these unsuspecting insects.

Like many jellyfish (but not the Pelagia noctiluca), the Aeolian jellyfish begins its life as a bottom-dwelling polyp - where "bottom" refers not to the seafloor, but the ocean-air interface. They have been found on certain recently-discovered very shallow seamounts in the Pacific. Thus the polyps rest with their holdfast on these plateau-like features, bathed in seawater, while their "mouths" reach out into the air. When they metamorphose into the medusa form, the jellies float up into the sky.

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