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A jellyfish bloom is defined as a substantial increase in a jellyfish population within a short time period; the result of a higher reproduction rate. [2] Since jellyfish naturally have high reproductive rates, high-density blooms can occur as a result of both behavioral and ecological causes.
Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in fresh water. Large, often colorful, jellyfish are common in coastal zones worldwide.
Unlike the hydrozoan jellyfish, Hydromedusae, Scyphomedusae lack a vellum, which is a circular membrane beneath the umbrella that helps propel the (usually smaller) Hydromedusae through the water. However, a ring of muscle fibres is present within the mesoglea around the rim of the dome, and the jellyfish swims by alternately contracting and ...
Cubozoa is a group commonly known as box jellyfish, that occur in tropical and warm temperate seas. They have cube-shaped, transparent medusae and are heavily-armed with venomous nematocysts. Cubozoans have planula larvae, which settle and develop into sessile polyps, which subsequently metamorphose into sexual medusae, [ 11 ] the oral end of ...
Among the radiata, jellyfish and their kin, the main form of swimming is to flex their cup shaped bodies. All jellyfish are free-swimming, although many of these spend most of their time swimming passively. Passive swimming is akin to gliding; the organism floats, using currents where it can, and does not exert any energy into controlling its ...
Jellyfish are slow swimmers, and most species form part of the plankton. Traditionally jellyfish have been viewed as trophic dead ends, minor players in the marine food web, gelatinous organisms with a body plan largely based on water that offers little nutritional value or interest for other organisms apart from a few specialised predators such as the ocean sunfish and the leatherback sea turtle.
The fluorescent proteins have been shown to help these predators obtain food as well. These proteins cause light to reflect off of the jellyfish, which makes it appear fluorescent. This light in the water can invoke supernormal stimuli. This stimuli will attract the prey closer to the flower hat jellyfish, where they can capture their next meal.
The medusa are pelagic, swimming organisms in the jellyfish form. [2] In the medusa stage, sperm and egg cells release into the water and fertilize to form polyps on benthic substrates. [7] Jellyfish tend to be more abundant in spring seasons, as the temperature and resource concentrations are ideal for an increase in reproduction during this ...