Portuguese man-o-war

A Portuguese man-of-war (Physalia physalis) washed up on a beach. Photo by Dr. Alex Mustard, more can be found at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Hydrozoa
Order: Siphonophorae
Family: Physaliidae
Genus: Physalia
Species: Physalia physalis

It’s summer time, the time of year I get to listen to the “jellyfish invasion.” Now, don’t get me wrong; jellies are increasing in number, and there are concerns about their large populations. However, Portuguese man-o-wars are not jellyfish—they’re siphonophores!

Siphonophores are the misunderstood cousins to jellyfish, especially Physalia physalis. Jellyfish are typically a single individual with a polyp stage. Siphonophores are a colony of individual organisms called polyps, and each group of individuals does a specific job for the colony.

Portuguese man-o-wars are made up of four separate polyps: the sails, the tentacles, the digestive organs, and reproductive system. Imagine that you and three of your clones, called zooids, live in an RV together. You are in charge of driving the RV, one clone is in charge of gathering food to feed everyone, one is the cook, and the other is responsible for replacing damaged or missing zooids. Without one of your clones, everyone in the RV would die, and RV would eventually stop moving. Same can be said about siphonophores and P. physalis.

The pneumatophore is the gas-filled bladder at the top; it’s the purple-bluish structure you can see floating on top of the water. This zooid is responsible for the colony’s movement. However, the gas-filled bladder works more like a sail; the wind and surface currents do the actual moving of the colony. This is how they got their name, because the gas-filled bladder resembled the sails of man-o-wars, a type of naval ship.

The tentacles are another organism, or zooid, of P. physalis. On average, the tentacles can extend 30 feet below water, but a single colony was recorded with tentacles as long as 165 feet! The tentacles contain venom-filled nematocysts, which they use to paralyze and capture prey. Portuguese man-o-wars feed on fish, shrimp, and other small creatures.

Gastrozooids are the polys in charge of digesting the prey and distributing the nutrients to the other polyps in the colony. Essentially, they are the digestive system of the colony. Unlike the sail and the tentacles, they have no distinctive “structure” on the colony, so they can’t be identified in a photograph.

The last type of zooid is responsible for reproduction. These polyps create other polyps for each of the groups, replacing those that have died or have been damaged. They are also responsible for exchanging genetic material with other Portuguese man-o-wars.

Portuguese man-o-wars are found in tropical and subtropical waters, and they can be found floating in large numbers—even in the thousands. I know in the US every summer, media warns the East Coast about these siphonophores washing up on public beaches.

P. phyaslis can be harmful to humans. I’d hate to be out swimming and get stung by the long tentacles! While live man-o-wars can be harmful to swimmers, dead ones are also a concern. While the venom is rarely fatal, it hurts worse than an army of wasp stings, and the nematocysts can still sting humans after death. So if you seem a dead one wash up on the beach—DON’T TOUCH IT!

If you notice Portuguese man-o-wars in the water or washed up, notify the lifeguards and everyone around you immediately. If you’ve been stung, do not use urine or vinegar on the inflamed area.

Dive manuals suggest that you carefully remove any remaining tentacles and flush the area with sea water, never fresh water. As soon as possible, immerse the affected area in hot water of at least 112°F for twenty minutes. This will denature the toxin and break up the chemicals.

I have never seen a Portuguese man-o-war in person despite living on the eastern coast of the United States and frequenting beaches in the summer. However, I don’t think I’m terribly upset with the idea, because with my luck, I’d get stung! Siphonophores are pretty interesting, though, and I can’t wait to share more with you!

Links and sources:
Reef Creature Identification Florida Caribbean Bahamas 3rd edition by Paul Humann, Ned DeLoach, and Les Wilk ⇐had the info on how to treat the sting
https://www.nationalgeographic.com/animals/invertebrates/p/portuguese-man-of-war/ ⇐in-depth look into the sections of the man-o-wars
https://oceanservice.noaa.gov/facts/portuguese-man-o-war.html ⇐simplified info
https://www.britannica.com/animal/Portuguese-man-of-war

Mushroom Coral

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Fungiidae
Genus: Fungia
Species: Fungia scruposa

Do you know what gets my attention? An old article about a species of coral that was documented eating jellyfish. But I’ll get to that later; first, I want to introduce you to Fungia scruposa, or the mushroom coral!

Found in the tropical waters of the Red Sea, Indian Ocean, and western Pacific Ocean, mushroom coral are unique for a few reasons. Unlike other hard corals, F. scruposa lives as a single individual instead of as a colony, much like the Atlantic mushroom coral of the family Mussidae. Don’t let their similar common names fool you, though. These two corals are not closely related to each other.

Juvenile mushroom coral start out as raised disks that attach to dead coral or rock. When they grow to about an inch in diameter, they detach themselves from their substrate. However, this does not mean that they’re super mobile. Instead, mushroom coral typically stay in the same area and inhabit the sediment or rubble.

But what happens if a strong wave comes through and turns them over? Fungia scruposa use their tentacles to right themselves when knocked over by waves or by another animal.

Mushroom coral get their name from their appearance. They have an irregular disk shape that is about 1 inch in diameter, sometimes a little larger. At the center of the disk is a raised mound with a deep-looking cut, which is the polyp’s mouth. The coral’s hard exoskeleton has several thin ridges that spread out from the center, making it look like the underside of some mushrooms.

Fun fact: did you know that the ridges on the undersides of mushrooms are called gills?

I’ve yet to see this coral while diving, but I absolutely cannot wait! Mushroom coral are unique for their class, because they live as solitary polyps and spend their adult lives not attached to anything. But on top of all that, they were also recorded eating whole jellyfish in the late 2000s—something that was completely unheard of!

There are some species of sea anemones—distant cousins to coral—that are known to eat jellyfish. However, these are the first hard corals that scientists have seen eating jellies. Unfortunately, the divers were only able to see the jellies disappear into the mouths of several mushroom coral, but they could never see how the mushroom coral captured the moon jellies. Still, it’s absolutely fascinating and may prove how resilient hard coral can be in a changing ocean environment.

And maybe you can be the researcher that discovers how they do it! Maybe you can discover more species of coral that will dine on jellyfish when the opportunity presents itself.

Sources and links:
Ocean The Definitive Visual Guide made by American Museum of Natural History
http://www.coralsoftheworld.org/species_factsheets/species_factsheet_summary/fungia-scruposa/
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8350000/8350972.stm ⇐an article about mushroom coral eating jellies
https://link.springer.com/article/10.1007/s00338-009-0507-7 ⇐another article about them eating jellies but with more detail

Sea Whip

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Gorgonacae
Family: Gorgoniidae
Genus: Leptogorgia
Species: Leptogorgia virgulata

I’ve realized that so far the only corals I have mentioned have been hard corals—reef builders. I will admit, that I like more hard corals than soft, but that doesn’t mean soft corals aren’t worth talking about. Continuing with my Chesapeake Bay theme, I’m going to talk about a native soft coral, the Sea Whip.

Cue the 80s music: “Crack that whip!” “Just whip it!”

The major difference between hard and soft corals is the composition of their bodies. Hard corals have permanent, rigid exoskeletons that house the coral polyps. These structures require large amounts of energy to build, which is why it can take a year for hard corals to grow just an inch, at best. Soft corals, however, lack that rigid calcium carbonate skeleton. Instead, soft corals are mostly made of living tissue that allows the soft corals to assume more creative shapes.

Sea whips, Leptogorgia virgulata, have long, thin branches that can grow up to a meter long. Their coloring can vary from red, to tan or orange, to purple. The polyps are always white, so sea whips look like they’re covered in white fuzz. Most soft corals are more colorful than their harder cousins.

Sea whips are found in reef environments and can tolerate low levels of salinity, so they are most common in nearshore areas that are more influenced by the tide. They range from New York to the Chesapeake Bay and from Florida to Brazil. In the Chesapeake Bay they thrive in the salty waters of the lower section of the bay.

L. virgulata are suspension feeders, so the polyps use their long tentacles to snag plankton and other tiny particles that are suspended in the water. When sea whips are born, the tiny polyps are carried by waves and currents. When they reach adulthood, so to speak, they become sessile meaning they cannot move from the hard substrate they land on. So they rely heavily on water circulation to stir up the water and bring in more plankton and nutrients for them to feed on.

I have yet to see a sea whip while diving, which is something I wish to change. But I wanted to share this soft coral to show that not all corals are found in tropical places, and that corals can be a lot more diverse than we think. And I’m happy to report that as of this writing, the populations of sea whips in the Chesapeake Bay and other monitored areas are considered stable!

Sources and more info:
https://www.chesapeakebay.net/discover/field-guide/entry/whip_coral
http://www.dnr.sc.gov/marine/sertc/octocoral%20guide/Leptogorgia_virgulata.htm
https://naturalhistory2.si.edu/smsfp/IRLSpec/Leptog_virgul.htm

Atlantic Mushroom Coral

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Mussidae
Genus: Scolymia
Species: Scolymia lacera

Not all hard coral grow to be great big structures. And while most coral are considered to be a colony of polyps—i.e., individuals living together—there are some that are quite solitary. Some of them, like the cup corals, live a bit differently than their cousins and distant relatives.

Atlantic Mushroom coral, or Scolymia lacera, is one of a few cup corals found in the Western Atlantic Ocean. In fact, they occasionally can be found in deep-reef environments and on reef walls in the waters around Florida, the Bahamas, and the Caribbean. They prefer well-lit areas on rocky surfaces and outcroppings, somewhere nice and stable with enough light to help out their zooxanthellae friends.

S. lacera varies in color from shades of light gray to green, blue-green, and brown. The few that I have seen while diving were a mix of blues and greens, almost like an alternating stripped pattern—though this isn’t the same of all individuals.

Unlike other coral, the whole structure that is S. lacera is made up of a single polyp. That’s right; this species of coral is not a colony like its other hard coral cousins. Instead, it is a single large, fleshy, roundish polyp that looks a bit rough around the edges—texture-wise, that is. The whole structure that you see is the corallite, or the skeletal cup in which an individual polyp sits in and can retract into. For S. lacera, the center of the corallite can be either flat or curved inward; rarely is it seen with a raised center.

The Atlantic Mushroom coral can grow to between 2.5 and 6 inches and is the only type of cup coral that you can identify in person if it’s larger than 4 inches in diameter. Any specimen smaller than 4 inches has to have its corallite structure examined for identification.

During the night and in turbid, cloudy conditions, the polys will extend their tentacles in the hopes of grabbing food.

I think these guys are really cool because they break the mold, so to speak, when it comes to most hard corals. Instead of being a colony of individuals, each structure is a single large individual. They’re also pretty neat to spot on the reefs because they can be these bright colorful spots amongst drab shades. When I first saw them I didn’t think they were coral. It wasn’t until I started taking classes and we discussed them that I learned what they were.

Sources:
Reef Coral Identification: Florida, Caribbean, Bahamas 3rd edition Paul Humann and Ned DeLoach

https://coralpedia.bio.warwick.ac.uk/en/corals/scolymia_lacera <–At the time of posting this article, I hadn’t gotten the rights to share any photos of the coral, but you can see pictures of this species at the link–please take a look!

Cannonball Jellyfish

Pictured here is a cannonball jellyfish. Notice the brown coloring around the bottom of its bell.

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
Order: Rhizostomeae
Family: Stomolophidae
Genus: Stomolophus
Species: Stomolophus meleargis

For today’s species we’re going to head back to the phylum Cnidaria! Honestly, it’s one of my favorite phyla because it has coral, jellyfish, and siphonophores which are all really cool creatures to check out. So let’s go ahead and cannonball into today’s topic…

I’m trying too hard again, aren’t I?

Stomolophus meleagris, also known as the Cannonball Jellyfish, is aptly named because it is about the size and shape of a cannonball used to load cannons in the days of massive sea voyages, pirates, and colonization.

Though, compared to cannonballs, S. meleagris can be a lot prettier to look at. They range in color from white to brown and will have very neat looking markings of various colors around the bases of their dome heads. Unlike other jellyfish, cannonball jellies don’t have tentacles. Instead, they have short, forked oral arms that extend out and away from the dome a little.

Cannonball jellyfish are native in both the Atlantic and the Pacific oceans, found right off the coast and in estuaries. They’re most abundant in the waters off the southeastern United States and the Gulf of Mexico. S. meleagris populations span from New England to Brazil in the Atlantic Ocean, and from the Sea of Japan to the South China Sea in the Pacific.

In fact, they are considered a common menu item in Asian markets and are dried and processed right after capture. Humans aren’t the only species that eats these guys; the most important is the endangered leatherback turtle, which only eats S. meleagris.

The jellies themselves eat macrocrustaceans, certain fish larvae, and zooplankton; and they eat by sucking water in where several tiny “mouths” are located. Fun fact: their scientific name roughly translates to “many mouthed hunter”.

Like other cnidarians, these guys do have stinging cells, however they don’t pose much of a threat to people. The pain of their stings isn’t too great, and it will cause mild irritation though, if you get stung in the eye that is a whole other can of worms—so make sure you always wear protective eyewear when in the ocean!

I first saw these jellies in aquariums growing up, and I always thought they looked a little goofy. I love watching them move about their tanks, and I can watch them for hours—just ask my husband!

I’ve never seen these guys while diving or snorkeling, which is a little disappointing, but there’s always next time. I’ve also not come across them while playing in the ocean on beach days, though I have seen plenty of them wash up on the sand. In fact, during one of my internships, I watched a few of them get pulled into estuaries during high tide, and it looked like they were just rolling with the current like a runaway cannonball!

Sources and cool links:
https://animaldiversity.org/accounts/Stomolophus_meleagris/ (totally check this out, it has a lot of good information!)
https://sites.google.com/site/barrierislandecology2013/aquatic-fauna/cannonball-jellyfish (this one also has more links and things to check out at the end.)
https://animalsake.com/facts-about-cannonball-jellyfish

Giant/Boulder Brain Coral

A boulder brain coral (Colpophyllia natans) growing on a coral reef. Photo taken by D. Alex Mustard, more can be found at www.amustard.com

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidarian
Class: Anthozoa
Order: Scleractinia
Family: Mussidae
Genus: Colpophyllia
Species: C. natans

First let me state that I have a love/hate relationship with common names. Most people call the Colpophyllia natans the Boulder Brain Coral; however, there are some texts and articles that call it the Giant Brain Coral. Why is this frustrating and worth mentioning? I spent a good chunk of time trying to confirm that these guys are the same species with different common names—I really didn’t want to make a fool of myself!

C. natans are named Boulder Brain Coral because they typically form large rounded structures that look like, drum roll please, boulders. They can also form large rounded plate-like structures, encrusting over rocks and existing coral colonies.

Like other brain coral, C. natans look like someone gave a chisel to a child and told them to go wild on the coral, creating a random pattern of valleys and ridges on the surface. A thin groove runs along the very top of the ridges, though you usually can’t see it when diving because you’re too far away (and if you’re not, you should be).

A second line is found halfway down the ridge where the angle decreases and slopes to create the valleys. The valleys are usually long and wandering, almost path-like, but sometimes they’re closed up and look more like individual cells squished together. The coral polyps are found within the valleys; the long ones containing multiple individuals, while the closed ones hold one or two polyps.

The ridges and valleys are normally different colors from each other. Ridges are either brown or gray while the valleys can be green, tan, or whitish.

You can commonly find them on reef tops or seaward reef slopes in the tropical waters of the Gulf of Mexico and the Caribbean. They can grow to have a diameter of up to 16 feet and can live as long as 100 years! C. natans are extremely popular tourist attractions, especially in the Florida Keys. But divers aren’t the only things these guys attract; they also attract all kinds of fish, including some gobies that live permanently on the coral.

I’ve only ever seen these guys during day dives—which, trust me, is still really cool to find them because of their size and coloring. However, they’re even better to see on a night dive because that’s when the polyps let out their tentacles to fish for zooplankton. I’ve been told that the coral can look completely different at night, and I can’t wait to see it for myself in person!

Sources and cool links:
Coral Reef Identification: Florida, Caribbean, Bahamas 3rd Edition by Paul Humann and Ned DeLoach
Ocean The Definitive Visual Guide made by the American Museum of Natural History
http://species-identification.org/species.php?species_group=caribbean_diving_guide&menuentry=soorten&id=305&tab=beschrijving
http://www.coralsoftheworld.org/species_factsheets/species_factsheet_summary/colpophyllia-natans/
https://www.sealifebase.ca/summary/Colpophyllia-natans.html
http://www.wildernessclassroom.com/wilderness-library/giant-brain-coral/

Golden Jellyfish

Photo of a Golden Jellyfish taken by Dr. Alexander Mustard. More of his photos can be found at http://www.amustard.com

Domain: Eurkaryota
Kingdom: Animalia
Phylum: Cnidaria
Class: Scyphozoa
Order: Rhizostomeae
Family: Mastigiidae
Genius: Mastigias
Species: papua etpisoni

Last time, we talked about Jellyfish Lake in the Palau region of the Caroline Islands archipelago. We learned that the meromictic lake, which has distinct layers of water that do not intermix, is the only place you can find Golden Jellyfish.

I highly recommend putting this place on your bucket list, not only would you get killer pictures but you’ll experience something unlike anywhere else in the world! Now, let’s move on to the special guest of the day.

Golden Jellyfish (Mastigias papua etpisoni) are a species of jellyfish that are closely related to the spotted jellyfish that can be found in the lagoons near Jellyfish Lake. Like coral, they benefit from a close relationship with zooxanthellae. What, did you think coral were the only ones to be best friends with the greatest algae of the ocean?

Like coral, the jellyfish house the zooxanthellae in their tissue which gives the jellyfish their golden color. They also have a mutualistic relationship with the algae; the golden jellies provide housing, waste that the algae uses for nutrients, and sunlight in exchange for the sugar that the zooxanthellae don’t use from photosynthesis.

In fact, it’s the sugar that gives the jellies all the energy they need to grow and reproduce, because they don’t gather food on their own since they lost their ability to sting prey through untold years of evolution. It also allows them to propel and migrate through the water, giving the zooxanthellae access to sunlight throughout the day as the sun moves across the sky, casting shadows on the lake.

This migration has a positive effect on the lake’s ecosystem, by stirring up the nutrients and microorganisms found in the water, providing one of the only sources of circulation in the layers they inhabit. So in this scenario everyone wins: the zooxanthellae get everything they need to make food, the jellies get all the leftovers, and the surface of the lake gets stirred up for the other organisms that call it home.

But the jellies aren’t without predators. They’re preyed upon by anemones that concentrate in areas that the jellies frequently migrate through, creating a bottleneck effect. Thankfully, the sheer number of Golden Jellyfish provide their predators a healthy diet without affecting the population too much.

I find these guys to be really cool creatures to study just because of their relationship with the zooxanthellae and their ecosystem. In general, the whole lake is fascinating and worth the time to read about. It’s a wonderful example of how crazy nature can become when isolated from what used to be similar environments and/or species.

Sources and cool links to check out:
https://palaudiveadventures.com/palau-jellyfish-lake/#Golden
https://www.nationalgeographic.com/animals/invertebrates/g/golden-jellyfish/