Not everything that looks like a sponge is a sponge. Covered by the “tunics” that give them their names, outwardly, tunicates resemble sponges and can be hard to tell apart from them. But their internal architecture is much more complex than sponges. IT’S THE “TUNIC” PART OF TUNICS’ ANATOMY THAT GIVES THEM THEIR SUPERFICIAL RESEMBLANCE TO SPONGES. The stiff, cellulose coverings that conceal tunicates’ inner workings may be very different from sponges’ walls of individual
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What are Copepods? They’re tiny, ungainly crustaceans. Often barely visible to us, they aren’t on anyone’s must see list. But they’re everywhere in the oceans, and one of the foundations of the web of life in the sea. Appreciate them. NOBODY GOES DIVING TO LOOK AT COPEPODS, AND IF THEY DO SEE THEM THEY’RE LIKELY TO BE GROSSED OUT. Generically, they’re just tiny crustaceans, mostly almost invisible, vaguely similar to shrimps and crabs, that happen
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What are fire corals? Well, they’re not true corals, although their talent for stinging certainly lives up to the fire part of its name. The tiny animals behind them are hydrocorals, hydroids that build calcium carbonate dwellings. They’re closer to jellyfishes than to the stony corals they sort of resemble. THE FIRST THING TO SAY ABOUT FIRE CORALS IS A WARNING: THEY LOOK TOTALLY INNOCENT. But touching them, presumably accidently, has caused many a diver
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What are sea urchins? Members of Class Echinoidea, they’re distant cousins of starfishes that boast imposing defenses and bad reputations. Do sea urchins sting? Not really. It’s more that they impale. But, if you don’t bother them, these oceanic pincushions won’t bother you. The trick is in not accidentally bothering them. RATHER THAN APPRECIATING SEA URCHINS, MOST PEOPLE FLEE FROM THEM, CAREFULLY. After all, the likely result of interacting with these oceanic pincushions while doing
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Basket stars are the starfish relatives you’re least likely to see in their full glory. Key basket star fact: They do their work of unfolding their tangled arms and capturing passing prey in the dead of night. Another: If you come across one during a night dive and stop to look at it – shining a light on it, of course – it’s going to fold right up and not quite disappear in front of
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Coral reefs are constantly being built up and simultaneously torn down, but Crown of Thorns Starfishes throw that equation out the window. Left to their own devices during population outbreaks, Acanthaster planci devour coral polyps and devastate reef habitats. Herewith: Crown of thorns starfish facts. IF CROWN OF THORNS STARFISHES HAD A THEME SONG, it would be Darth Vader-type music. So destructive are these rogue echinoderms that their very name is synonymous with bad news
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UNLIKELY ANIMALS THEY MAY SEEM TO OUR EYES, but feather stars are full-fledged members of the animal kingdom. Here’s a key feather star fact: They may seem to be fixed in place in their perches on coral heads or sponges or sea rods, but these crinoid creatures eat, reproduce and move like other animals. As a bonus, they’re often beautiful and compelling. TECHNICALLY, FEATHER STARS HAVE ARMS JUST LIKE THEIR STARFISH AND BRITTLESTAR COUSINS. At
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If you think of brittlestars as just a variation on the familiar, pointy starfish, think again. They’re made quite differently, they act differently and they live quite a different lifestyle. It’s all in the long, whip-like arms. BRITTLESTARS ARE MORE THAN JUST TRADITIONAL STARFISHES WITH LONG, SINUOUS ARMS AND LAID-BACK ATTITUDES. Actually, there are many differences between brittlestars and star-shaped starfishes, both in body design and behavior. In contrast to sea stars, brittlestars have flexible,
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Researchers have discovered that seemingly benign upside-down jellyfish utilize a unique, previously unrecognized weapon to capture prey: “Stinging mucus grenades.” It explains the “stinging water” pain that divers, snorkelers and waders sometimes experience without coming into actual contact with the jellies. Upside-down jellyfish have been recognized for some 200 years, but nobody knew this until now. TO ALL APPEARANCES, UPSIDE-DOWN JELLYFISH LIKE CASSIOPEA XAMACHANA spend their days resting on the shallow bottoms of reefs and
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What are sponges? They’re animals, perhaps animals that stretch our conception of the term, but animals for sure. It’s easy to dismiss them as just backdrop scenery to more exotic stuff on the reef. But ocean sponges come in amazing shapes and colors, chug along with body features unique in the animal kingdom and perform important reef-related roles. Sponges were among the earliest arrivals in the ocean. And, if corals disappear, sponges may be the
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