Dictionary of Meaning

<<Back
Please select a letter:
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

Sea nettle

*** Shopping-Tip: Sea nettle
{{Taxobox | color = pink | name = Sea nettle | image = Six-Sea-Nettles.jpg | image_width = 240px | regnum = Animalia | phylum = Cnidaria | classis = Scyphozoa | ordo = Semaeostomeae | familia = Pelagiidae | genus = ''Chrysaora'' | species = '''''C. quinquecirrha''''' | binomial = ''Chrysaora quinquecirrha'' | binomial_authority = (Desor, 1848) }} The stinging '''sea nettle''' (''Chrysaora quinquecirrha'') is a species of jellyfish occurring particularly in Atlantic estuary estuaries. It is a bell-shaped invertebrate, usually semi-transparent and with small, white dots and reddish-brown stripes; Sea nettles without stripes have a bell that appears white or opaque. The nettle's sting (biology) sting is rated from "moderate" to "severe", and can be pernicious to smaller prey; it is not, however, potent enough to cause human death, except by allergy allergic reaction. The sea nettle is symmetry symmetrical, marine, and carnivore carnivorous. Its mouth is located at the center of one end of the body, which opens to a gastrovascular cavity that is used for digestion. It has tentacles that surround the mouth to capture food. Nettles have no excretory or respiratory organ (anatomy) organs.

Life cycle and reproduction
The nettle passes though two different body forms during its biological life cycle life cycle. The most familiar form is the Medusa (biology) medusa, while the smaller form is the larval stage. The male sea nettle fertilizes the female by releasing its sperm into the surrounding the water. The female must then pump the sperm past her eggs, at which point the sperm should fuse with the ovum ova and the reproductive process will begin. After that, early embryotic development begins either inside the female or in brood pouches along the oral arms. Next, small, swimming larvae (planulae) leave the mouth or brood pouches and enter the water column. Soon after, the larvae seek shade and attach to the bottom of the water, forming polyps. The polyps then divide and bud into young jellyfish (ephyra). In a few weeks, an ephyra will grow into an adult medusa, completing its complex life cycle. The resulting jellyfish should live for three to six months in favourable circumstances.

Habitat
Sea nettles are most commonly seen near the coasts during the summer. Salinity and temperature are the two most important factors for a sea nettle habitat. They prefer water with little salinity, but can easily adapt. They eat their favorite meal, combjelly combjellies, in the Chesapeake Bay; because of their ubiquitous presence there, the Bay is usually unswimmable in late summer and fall.

Feeding habits
Stinging sea nettles are carnivore carnivorous. They generally feed on zooplankton, ctenophores, other jellies, and sometimes crustaceans. Nettles immobilize and obtain their prey using their stinging tentacles. After that, the prey is transported to the gastrovascular cavity where it is subsequently digested. Nettles also eat young minnows, bay anchovy eggs, worms, and mosquito larvae.

Defense mechanisms
Image:Sea nettle.jpg thumb|200px|right|A group of Sea nettles. Each nettle tentacle is coated with thousands of microscopic nematocysts; in turn, every individual nematocyst has a "trigger" (cnidocil) paired with a capsule containing a coiled stinging filament. Upon contact, the cnidocil will immediantly initiate a process which ejects the venom-coated filament from its capsule and into the target. This will inject toxins capable of killing smaller prey or stunning perceived predators. On humans, this will most likely cause a nonlethal, but nevertheless painful rash typically persisting for about 20 minutes. Some earlier cases of nettle stings from the Philippines reportedly had more severe effects: one account describes a sting causing vascular insufficiency, and another mononeuritis. {{ref|Caravati}} Rather than toxic substances, some nematocysts contain adhesion used to entangle or anchor its target.

External link

- NOAA forecast of sea nettle distribution in the Chesapeake Bay

References
#{{note|Caravati}} {{cite book | last = Caravati| first = E Martin| title = Medical Toxicology | pages = 1626| year = 2004| publisher = Lippincott Williams & Wilkins| id = ISBN 0781728452}} *{{cite book | last = MacKay| first = Bryan| title = Hiking, Cycling, and Canoeing in Maryland: A Family Guide | pages = 244-245| year = 1995| publisher = Johns Hopkins University Press| id = ISBN 0801850355}} Category:Cnidarians

*** Shopping-Tip: Sea nettle