Living Ribbons of the Twilight Zone

In the dim, blue waters of the ocean’s twilight zone, long, transparent ribbons drift through the darkness. Some pulse softly with bioluminescent light. Others trail delicate tentacles, like threads of glass. They are the mysterious siphonophores—creatures that are not just one animal; they are an entire colony, living as a single being.

Siphonophore
Ecology & Science

Many bodies, one life

A siphonophore is composed of hundreds, sometimes thousands, of tiny individuals called zooids. Each zooid is genetically identical, yet specialised for a particular task. Some swim, some feed, some reproduce, and some have stinging cells that they use not only to kill prey, but also to defend the colony.

Though each zooid is a separate animal, none can survive independently. Over the abyss of time in which siphonophores evolved, they became so integrated that the colony functions as one organism.

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The Charm of Jellyfish: Crystal Creatures From the Magical Depths

Jellyfish are graceful, delicate and mesmerising life forms that have inhabited the world’s oceans for millions of years. Pietro Cimmino explores the characteristics of jellyfish, their role in marine ecosystems and their importance in our scientific future.

Words:
Pietro Cimmino
Images:
Lorenzo Moscia
➥ Download the full article as pdf ⬅︎
Ecology & Science

Jellyfish are among the most fascinating and mysterious creatures in the oceans. Their crystalline appearance, slow, hypnotic movements and long evolutionary history have made them the subject of legends and scientific studies for centuries. These fragile and delicate-looking animals hide a surprising side: they have survived in the Earth’s seas for over 500 million years, making them some of the oldest living creatures on the planet. 

How upside-down jellyfish can make the water sting

When this species of upside-down jellyfish feels threatened, it sends out popcorn-shaped packages that pack a punch that can't be ignored.

Here's what the Cassiopea xamachana jellyfish looks like. Photo taken at aquarium in Loro Parque
Ecology & Science

In some tropical waters like the Florida Keys mangrove forests, for snorkellers to stay safe, it’s not enough to not touch anything. It may not be a good idea to enter the water in the first place.

That’s because sometimes it seems that the water itself can sting, causing rashes on a snorkeller's skin.

The real culprit is not some mutant strain of water molecules. Rather, it is a species of upside-down jellyfish that lives on the ocean floor. Called Cassiopea xamachana, this jellyfish can also be found in places like the Caribbean Sea and the Gulf of Mexico.

How upside-down jellyfish can make the water sting

When this species of upside-down jellyfish feels threatened, it sends out popcorn-shaped packages that pack a punch that can't be ignored.

Ecology & Science

In some tropical waters like the Florida Keys mangrove forests, for snorkellers to stay safe, it’s not enough to not touch anything. It may not be a good idea to enter the water in the first place.

That’s because sometimes it seems that the water itself can sting, causing rashes on a snorkeller's skin.

The real culprit is not some mutant strain of water molecules. Rather, it is a species of upside-down jellyfish that lives on the ocean floor. Called Cassiopea xamachana, this jellyfish can also be found in places like the Caribbean Sea and the Gulf of Mexico.

How upside-down jellyfish can make the water sting

When this species of upside-down jellyfish feels threatened, it sends out popcorn-shaped packages that pack a punch that can't be ignored.

Here's what the Cassiopea xamachana jellyfish looks like. Photo taken at aquarium in Loro Parque
Ecology & Science

In some tropical waters like the Florida Keys mangrove forests, for snorkellers to stay safe, it’s not enough to not touch anything. It may not be a good idea to enter the water in the first place.

That’s because sometimes it seems that the water itself can sting, causing rashes on a snorkeller's skin.

The real culprit is not some mutant strain of water molecules. Rather, it is a species of upside-down jellyfish that lives on the ocean floor. Called Cassiopea xamachana, this jellyfish can also be found in places like the Caribbean Sea and the Gulf of Mexico.

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Animals with Missiles

What? Animals in the sea armed with missiles? And thousands of them? Yes, you’ve read correctly. No, sea lions or dolphins have not been stealing Tomahawk missiles from any of the American navy bases. But did you know that jellyfishes, sea anemones and corals contain thousands of “miniature missiles” to kill prey and sting intruders? We will look at bit closer at this missile battery mechanism here.

Words:
Michael Arvedlund
Peter Symes
Images:
Tyge Dahl Hermansen
Michael Arvedlund
Peter Symes
Download the full article as pdf ⬇︎
Ecology & Science

Cnidaria

The stinging cells – the cnidae contain each an reversible hollow tube arranged in a spiral, with a harpoon like end (see b/w photo above and drawing net page). They are placed in the surface of the tentacles and the oral disk of the Cnidarians.

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Coral Bleaching

Can tropical stony corals adapt to bleaching?

Words:
Michael Arvedlung and Peter Symes
Images:
Download the full article as pdf ⬇︎
Ecology & Science

But what is coral bleaching actually? No, it is not mum that has stinted bleach over the lovely colourful tropical corals….although it looks like it. The explanation is quite different. Normally, tropical shallow-water stony corals only exist to dept’s where sunlight is able to reach. This is because they contain in their tissue a specialized kind of brown algae called zooxanthellae. These algae are crucial for the survival of the coral.

 

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