Scyphozoan Life Cycle

1. Planula : The free-swimming medusa is either female or male and produces eggs or sperm which combine to produce a larva, called a planula. The planula is planktonic and will float around until it finds a substrate to bind to.

2. Scyphistoma : Once the planula binds to a substrate it develops into a scyphistoma. Scyphistoma is a feeding polyp with protruding tentacles on top used to catch food particles.

3. Strobila : The polyp soon turns into a reproductive polyp with stacks of strobilae. The strobilae are immature medusa that are being asexually reproduced by the polyp.

4. Ephyra : When a strobila is mature it breaks away from the reproductive polyp as a planktonic ephyra.

5. Medusa : The ephyra matures into a full grown medusa.

Check out these yellow zoanthids! Zoanthids are invertebrates related to reef-building corals and sea anemones. 

These were spotted colonizing the base of a dead golden octocoral in the deep waters of National Marine Sanctuary of American Samoa! 

(Photo courtesy of the NOAA Office of Ocean Exploration and Research, 2017 American Samoa) 

Have you ever seen coral under the microscope?

Well now you have! This is a coral called Frogspawn coral. One of its tentacles had to be removed because it was attacking another coral! See the bleached edges of the red plate coral?

This is a common behavior among corals and sea anemones. They can send out those extended tentacles filled with stinging nematocysts, which are basically poisonous harpoons. Some of you might have had some personal experience with nematocysts- if you’ve ever had close contact with a jellyfish, that’s what caused the stinging! Makes sense, since jellyfish and corals are actually closely related

And that’s what they look like at high magnification. The arrow on the left is pointing to the spiny string that can penetrate like a hypodermic needle. The arrow on the right is the empty cell were the nematocyst was previously coiled up. Overlaying the cell is a cell with a nematocyst that has not yet been released. Note all the strings in the background- those are more nematocysts! 

You’ll notice that the tentacle is chock-full of little red-brown dots. Those are actually symbiotic algae called zooxanthellae (don’t ask me to pronounce that) that live in coral by the millions and help the coral gain energy. To be more specific, those algae are dinoflagellates, which I’ve featured on my blog before

There’s a whole world to discover in Olympic Coast National Marine Sanctuary tidepools! 

These are giant green anemones, which can often be spotted in the rocky tidepools lining the sanctuary. Their brilliant green color comes from symbiotic algae that live within their tissues! 

(Photo: Shawn Sheltren/NPS)


Aquarist Confession: I don’t have a lot of coral experience, so my options aren’t as diverse as a hobbyist or coral enthusiast, but frogspawn coral has got to be one of the prettiest corals I have ever worked with.



Aerial checks of more than 900 individual reefs showed the spread varies dramatically along its 2,300 kilometres, from 90 per cent north of Port Douglas to less than 10 per cent south of Mackay.  

Coral bleaching is when abnormal environmental conditions cause coral to expel tiny photosynthetic algae, called zooxanthellae. Loss of colourful algae causes coral to turn white and “bleach” -Bleached coral can recover if the temperature drops and zooxanthellae are able to recolonise them, otherwise it may die.

The Great Barrier Reef has been threatened with mass bleaching due to weather conditions El Niño and the rapid climate change. 

The southern third of the Great Barrier Reef fortunately cooled down late in summer due to ex-cyclone Winston. Researchers expect the central and southern corals to regain their colour and recover over the next few months

Requested by @shadowskiel, @calvin-reads-problem-sleuth, and anonymously

Nihilego is a fantastic combination of two terrifying things: jellyfish and parasites. Nihilego’s pokédex entry states “it’s unclear whether or not this Pokémon is sentient,” and that’s as good of a description of a jellyfish as any.

Jellyfish don’t have brains, bones, hearts, or blood. They don’t have a respiratory system (lungs or gills) to breathe, but they do absorb oxygen through their skin. Some are microscopic, and others longer than a blue whale. Some of them are immortal and can de-age themselves. They’re made of 98% water, they barely have a nervous system…and yet these creatures have been around on our planet for more than 650 million years, so they must be doing something right. In fact, jellyfish are the oldest multi-organ creatures on the planet. Despite everything they lack, jellyfish do have some organs: a mouth and a digestive system, and reproductive organs, for example.

There are over 2000 different species of jellyfish, so let’s just narrow it down to those who, like Nihilego, are also parasites: the myxozoans. Myxozoans are in the same phylum as jellyfish, Cnidaria, but are curious little organisms who go one step beyond jellyfish, not even having a mouth or guts. And like many parasites, they literally can’t survive unless they are infecting a host. They do still have stinging tentacles, though, so I guess that’s good.

Myxozoans live inside the bones and cartilage of fish, where they can reproduce inside and cripple their host, or even to some extent, control the fish. Some Myxozoans cause neurological damage that causes a fish to uncontrollably swim in circles. 

When their hosts die, myxozoans use their little jellyfish stingers to sting, therefore infecting, a new fish. 

As shown in Pokémon Sun and Moon, Nihilego has some adverse neurological effects when it infects a host: namely, what it did with Lusamine. If Nihilego is like a Myxozoan, it needs to bond with a human in order to reproduce: and it likely would have killed Lusamine if it could have completed the process.

Nihilego is a jellyfish-like parasitic Myxozoan. It does not have a brain, a respiratory system, a mouth, or guts. It infects hosts and often causes neurological damage.

Come sail away with this Velella velella in Cordell Bank National Marine Sanctuary! 

Vellela vellela, or the by-the-wind sailor, is a small, unique species of jellyfish that has a vertical sail atop its float, helping it to travel. This sail is oriented at a diagonal to the animal’s body axis, allowing it to take advantage of prevailing wind currents that push the animal across the sea. Scientists have found that populations along the California coast tend to have sails oriented to the right, while populations farther west in the Pacific tend to have sails oriented to the left, reflecting differing wind patterns in their respective regions! 

(Photo: NOAA)