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!
Do you know the significance of the number 42? Bottlenose dolphins sing a song about Earth’s destruction; quick, ask them before they leave the planet!
The world’s about to be destroyed There’s no point getting all annoyed Lie back and let the planet dissolve around you
Never mind; the dolphins are too busy. Forty-two is the answer to the ultimate question of life, the universe, and everything—at least, according to the super computer Deep Thought and Douglas Adams in The Hitchhiker’s Guide to the Galaxy!
For me, this is the 42nd post on this blog, and I thought I’d be funny about it. So, no, the world is not going to end and all the bottlenose dolphins aren’t breaking out into song before jetting themselves out of the ocean and into space. If you haven’t seen the movie or read the books, I highly recommend them.
Now, let’s get back to our regularly scheduled programming!
The common bottlenose dolphin, Tursiops truncatus, is one of the most exposed dolphins in the world. They are very common in zoos and aquariums. They make appearances in movies or even star in them, like Flipper. They also like to hang around boats and can be seen close to the beach. When people think of dolphins, they usually imagine a T. truncatus.
Bottlenose dolphins are found in a variety of habitats around the world. Their distribution stretches from the temperate waters of the Northern Hemisphere to the temperate waters of the Southern Hemisphere. Local populations of the common bottlenose dolphin can be found along every continent but Antarctica.
Tursiops truncatus have a wide head and body, short stubby beak, long flippers, and a relatively tall dorsal fin. These dolphins have a crease between the beak and the melon that allows researchers to distinguish common bottlenose dolphins from similar-looking species, like the Rough-toothed dolphins.
The common bottlenose can be found inshore of most coasts, living in or near bays, estuaries, coral reefs, or even the mouths of rivers that link directly to the sea. Other populations of dolphins can be found offshore in deeper waters. Offshore bottlenose dolphins look a little different from their inshore relatives with thicker, darker bodies and shorter flippers, though genetically they are the same species.
Bottlenose dolphins are extremely sociable creatures, between themselves and other animals as well, including pilot whales and human swimmers. Despite their stereotypical friendliness, they have been reported to be unfriendly towards other species of dolphins. Along with acting sociable, dolphins emit a wide variety of clicks, squeaks, and squeals that they use to communicate with each other and other pods of bottlenose. Research suggests that each dolphin has a specific sound associated with it, like a name, that other dolphins use.
T. truncatus are highly intelligent creatures. Depending on their prey, the dolphins use various tools and techniques to catch their food. Some use echolocation, the emission of high frequency sound, to locate and confuse fish. Others have been seen rushing a school toward the shore, getting the fish nearly beached before the dolphins catch and eat them.
The diet of the dolphin changes depending on where the pod is located. For instance, inshore dolphins may have more crustaceans and shrimp in their diet while offshore bottlenose have more deep sea fish and squids in theirs. Bottlenose dolphins are remarkably adaptable, even to the extent of learning to identify fishing vessels and shrimp boats, and incorporating the fisherman’s actions into their hunting behavior.
Overall, their population numbers are good. The species as a whole is not a concern for extinction. Local populations, however, are decreasing due to viral outbreaks, weaker immune systems due to biotoxins and pollution, loss of habitat, and depleted fishing stocks. On a smaller scale, many local populations of inshore bottlenose dolphins need help.
When I first got interested in the ocean, I wanted to work with dolphins. In elementary school, I had a well-worn book on dolphins and sharks that was a companion novel to a Magic Treehouse book. I was so proud of it!
Now my focus has changed to coral, and I have a love/hate relationship with dolphins. I absolutely love dolphins; they are beautiful, intelligent creatures that want nothing more than to eat and play—and boy, do they play! However, sometimes I feel that they get too much attention from the public, and other sea creatures are hurt by it, as in the example of dolphin-safe tuna.
I don’t have time to get into the history and nuances of dolphin-safe tuna; I’ll leave that topic for a future post. The common bottlenose is one species that I’ve loved since I was a child. My biggest complaint is that dolphins get more empathy—because they are warm-blooded creatures like us—than any other creature in the ocean, except for maybe polar bears. This lack of human empathy toward cold-blooded creatures can have a negative impact on the ocean, and, ultimately, dolphins to.
After spending some time talking about the horrors of invasive species, let me throw you a curve ball. We should all agree that invasive/nonnative species are harmful to us and the environments that they infiltrate. However, not all native species are good for their environment either.
How can organisms that are part of the natural balance of their environment be bad for it?
The simplest explanation I can give is this example. Our bodies need potassium to function properly, which we get from food like bananas. If our bodies don’t have enough potassium, then our muscles cramp and we can become stiff and sore. If we consume too much potassium, then it can poison and even kill us. Don’t worry, though; you would have to consume a truck load of bananas in a single day for that to happen.
Like our own bodies, environments need everything in moderation.
Alexandrium monilatum is a single-celled dinoflagellate found in the warm waters of the Atlantic Ocean, Gulf of Mexico, Caribbean Sea, parts of the Pacific Ocean, and the Chesapeake Bay. It is a special kind of bioluminescent algae; when agitated, the organism produces its own light in the form of a soft blue glow.
This dinoflagellate can reproduce sexually and asexually, meaning it can use its own genetic material to make copies of itself without the use of other individuals. It can also produce chains of individuals, ranging from 2 to 80 A. monilatum per strand.
A. monilatum uses photosynthesis to create its own food, making it a phototroph. It is preyed upon by small fish and filter feeders, making it part of the base of the food chain. So how can this armored alga be a bad thing? It sounds so productive, and it even glows blue at night when waves stirs the water!
The problem with A. monilatum is that it is considered a Harmful Algal Bloom (HAB) species. When conditions are right, this species will reproduce faster than it can be consumed by its predators, causing an algal bloom in the water. Blooms are large patches of algae that are seen by the naked eye, meaning there are millions of individuals concentrated in a single area.
Blooms are considered a problem because the water contains a finite amount of nutrients available to the algae. Once the supply runs out, it’ll take time to replace those needed nutrients. So these blooms are extremely productive for a short time, before the algae run out of food and die. When they die, they start to decompose. The process of decomposition takes up a lot of oxygen, and without the photosynthesizers there to replace the oxygen being used, the water becomes hypoxic—or worse, anoxic.
Once the amount of dissolved oxygen in the water is depleted, the area becomes a dead zone, and all the fish and other marine organisms either leave or suffocate in the water. Dead zones aren’t always permanent; however, they are still an inconvenience to the marine life and to us and should be prevented at all cost.
It is not my purpose to make Alexandrium monilatum out to be a bad guy, just to show that even native species can harm their environment under certain conditions. Algal blooms, or red tides, can be caused by a steep increase in important nutrients found in fertilizers, which enter the water as run-off from nearby farms, gardens, and agricultural facilities. A boom in available food causes a boom in creatures that depend on it, and that’s true no matter the species.
Bioluminescent algae are fascinating. I was lucky enough to swim at night in a lake full of a species of bioluminescent algae, though I’m uncertain what species it was. It was a magical experience that I will never forget, so I was excited to talk about A. monilatum and to discuss the importance of balance within an ecosystem.
Invasive is such a harsh word. How can a natural creature be considered an invasive species? Nobody likes weeds, but everyone likes pretty fish and colorful birds—so, how can those be considered dangerous?
An invasive species is any living organism that is found outside of their native environment and has or will cause harm. The harm it can cause can be to the nonnative environment itself, the economy, or humans, or a combination of the three.
The zebra mussels that I’ve spoken about are an example of an invasive species in the United States. They are native to the freshwaters of Eurasia but somehow made it to the United States in the 1980s. Wherever the zebra mussels have been found, outside of Eurasia, they have outcompeted all native species and have changed the environments that they have invaded.
Another example is the lionfish. Its native habitat is the Indo-Pacific Ocean, however, it has made its way to the Atlantic Ocean. It reproduces rather successfully and has no natural predators in the Atlantic waters, so it has decimated many coral reef populations by devouring the herbivorous fish that help keep the reefs clean of algae. Without the algae eaters, the coral are smothered by the thick blankets of algae that naturally grow on them.
Not all invasive species are easy to comprehend at first. For instance, in many countries, domesticated cats and dogs are considered to be invasive species. How can Mittens or Spike be considered invasive? Humans absolutely love them and they (mostly) love us!
Dogs, and especially cats, are considered invasive species in many countries outside of Europe. They were brought over during the time of colonization, and their populations quickly grew unchecked. Dogs threaten native small animal populations, and cats wreak havoc on the native bird populations. For example, the Galapagos penguin population has been hit hard by the invasive house cat populations in South America.
Invasive species don’t have to look exotic. Sometimes they look normal, or they’re hard to notice at all. Invasive species can include plants, animals, fungi, insects, and microbes. And their effects on the local populations can be devastating, as when settlers first encountered native people, and the germs the settlers brought with them killed a lot of the native people of the land who did not have the same immunities built up as the settlers did.
Invasive species can also cause harm in other ways. New microbes introduced to an area can cause illness in people. Insects that have hitchhiked in shipping containers can run wild in new places and hurt the people there, like invasive species of hornets or spiders. Invasive jellyfish can fill the waters and harm beach goers.
Invasive species can even cause harm economically. Invasive hornets destroy beehives that produce honey to be sold. Zebra mussels clog pipes and encrust boats; it costs a lot of money to remove them, and it’s usually not a one-time expense. Lionfish have made coral reefs barren, reducing the populations of game and harvestable fish to low numbers, and impacting aquatic tourism.
Luckily, there are ways to handle invasive species. The best way is to prevent them from entering delicate ecosystems that they don’t belong to. For humans, that means being more careful when transporting food and supplies over long distances. It means finding new owners for exotic animals when you no longer want or can care for them—don’t just release them into the wild!
There are also ways to reduce invasive species numbers. For instance, many places around Florida and the Caribbean offer cash prizes for lionfish through spear-hunting competitions. Or you can encourage local chefs and restaurants to serve invasive species on the menu. The National Aquarium in Baltimore, Maryland frequently serves invasive fish in their diner.
I’ve eaten lionfish, and it’s pretty tasty! Mine was served Jamaican style, featuring a lot of spices that I wasn’t used to, but if prepared properly, it’s a great fish to eat. I’ve also had invasive catfish that was found in our local waters, and it didn’t taste that different from the native catfish, just maybe a little sweeter. So there are all kinds of ways to deal with invasive species, but it’s up to us to keep them in check!
Species: D. polymorpha
Today, we’re going to talk about zebra mussels. We’re not going to talk about zebra muscles like I had originally written down on my blog schedule. Honestly, why would I talk about the muscles of a zebra? They’re not even aquatic!
I know that was a lame introduction. It just doesn’t have enough strength to land a clever opening—maybe it needs more mussels…
Okay, I’ll stop!
Zebra mussels, D. polymorha, are freshwater bivalves native to Eurasia. Bivalves are shelled creatures; specifically mollusks with two shells that close together, like clams and oysters. Zebra mussels are about an inch long and are shaped liked a stretched out “D”. They are named from the black, zigzag patterning on their shells.
Humans can be so creative with their naming schemes.
Zebra mussels have a relatively short life span, between 2‒5 years, reaching reproductive maturity at 2 years of age. Each female can produce up to a million eggs per year, spewing them into the surrounding water and using the currents to transport the eggs.
The reason I’m bring up D. polymorpha is because it is an invasive species in the United States and Canada. The mussels were first discovered in the early 1980s near the Great Lakes and are believed to have been transported by accident in the ballast water of a ship. Since then they have been found in the Great Lakes, the Mississippi and St. Croix rivers, and the Chesapeake Bay.
Why are the zebra mussels bad for these environments? Don’t they help filter the water in their surroundings, and isn’t that a good thing?
In their natural habitat their job as filter feeders is absolutely amazing; in other habitats, it can have devastating effects. In fact, zebra mussels are so efficient as filter feeders that they can clean a body of water of particulates in record time, faster than the native filter feeders. But this is not a good thing.
The environments that the mussels invade have a special balance that is maintained by the native populations of animals. If you change one aspect of that balance, then it creates a domino effect.
Let’s say that we have an imaginary river, the River Sága, which is home to large, healthy beds of freshwater bivalves called blue purses (not a real bivalve). In this river there are also a few species of fish that go there to spawn and where the juvenile fish live until they’re big enough to move on. One day, an old fisherman dumps water into the River Sága from his boat and unknowingly releases several thousand eggs of the zebra mussel. A couple of years later, the river is no longer the same. The once-healthy beds of blue purses are now completely covered in smaller bivalves, smothering the native species. The water of the river is the clearest it’s ever been, but downstream there are enormous patches of algae, and there are no fish to be seen. What was once a nice fishing spot for man and animal alike is now barren, save for the zebra mussels and the algae.
Zebra mussels, like any invasive species, are horrible for the environments that they infiltrate because they have no natural predators, and they often outcompete the native species. Because zebra mussels are so good at filtering the water, it makes it easier for predators to find their prey in the water, whether it’s a larger fish or a bird hunting the juveniles that have spawned there. And because zebra mussels reproduce so much, they can easily smother their competitors, becoming the dominate species of the environment and changing it for the worse.
Zebra mussels also have an impact on human property. They have been known to block the drainage pipes of factories. They can incapacitate boats by clogging pipes and engines, or even by covering the sides of the boat and making it too heavy to float properly. It can take an absurd amount of money to remove them, and we have to do it often because they regularly come back and are so hard to eliminate.
I wanted to talk about zebra mussels because they have been noticed in the Chesapeake Bay, which is an important part of my life, and because it helps introduce the topic of invasive species. From what I understand, there is not much you can do once the zebra mussels appear, only that we must strive to prevent their spread elsewhere. But this also means that there is a potential opportunity for you, because maybe you can find a way to remove them from their nonnative habitats.
I absolutely love the written word. Why? Because we can have so many names for the same subject/object and it can confuse those who don’t know all the different words.
For instance, estuaries can also called be bays, sounds, sloughs, or lagoons. Though, a coastal lagoon is different from an estuary, but we’ll get to that in a later post—let’s just agree for now that common names are a blessing and a curse.
Estuary is a very broad term because it includes both fresh and brackish water ecosystems, and there are three types of estuaries: salt-wedge, partially mixed, and fully mixed. Each type of estuary is determined by how the fresh and salt water mix.
Today, we’ll just start with a broad overview of coastal estuaries.
An estuary is an area where fresh water from a large stream or river mixes with the salt water from the ocean. This mixing results in brackish water, a chaotic medium between fresh and salt water. Brackish water is too salty to be considered fresh water, but not salty enough to be sea water.
What do I mean by chaotic? The salinity of an estuary changes with every season, passing day, and cycle of the tides. For instance, at high tide the salinity will be higher than at low tide because there is more ocean water mixing with the river water. During the rainy season, the salinity will be lower because the river/stream will have a lot more fresh water from the land runoff than normal, mixing more fresh water than usual with the ocean water. This chaotic nature makes estuaries interesting ecosystems for organisms to adapt to.
Due to their long, funnel-like shape, most estuaries don’t experience a gradual rise and fall of the tides. Instead, the tides rush into the estuary with such force that they create strong currents and even wall-like waves called tidal bores. With the tide comes offshore sediments that get deposited in the estuary as mud, and with the high rate of sedimentation, this mud builds up and creates special habitats within the estuary. In the tropics, these mud areas are called mangrove swamps; everywhere else, they’re called tidal mudflats and salt marshes—but I’ll discuss these habitats in detail later.
Estuaries are crucial to both the land and the ocean.
Estuaries provide a rich source of food for waders and shorebirds. Various types of migratory birds will stop at an estuary to consume worms and crustaceans that live in the mud before continuing on their way. Estuaries also provide breeding grounds for both land and aquatic animals.
One of the greatest functions of an estuary is that it is a natural water filter, helping to ensure that the water coming from the land is as clean as possible before entering the ocean. The process of filtration is complicated and requires a lot more explanation than I have time for today.
When we speak, hum, sing, etc. we make those noises by vibrating our vocal cords. Sometimes, when you hum or hold a note, you can even feel the vocal cords in your throat. Whales can also sing. In fact, male humpback whales sing to communicate and can be heard for miles by other whales, each “song” lasting up to about 30 minutes.
Fun fact: scientists don’t know how humpbacks pull off singing, because they have no vocal cord.
Humpback whales get their common name from the way they arch their back when diving. They aren’t the largest or heaviest whales in the world, but they do have the longest flippers. Their fluke and wing-like flippers can help you identify the whale as a Megatera novaeangliae, and the unique white splash-like markings on those appendages allow scientists to distinguish between individuals, like a fingerprint.
These creatures can be found in all of the world’s oceans, in both tropical and polar regions, though they don’t venture too far up into the poles.
M. novaeangliae are a type of baleen whale, meaning that they don’t have teeth like we do, and they take in large amounts of water that, hopefully, contain a lot of krill and small fish. Humpback whales are different from other baleens because they can actually trap their prey through a process that is better to watch in a video or documentary (e.g. Blue Planet).
When humpbacks find swarms of krill or schools of small fish, they will try to gather them together. They do this by exhaling air while they spiral around their prey. This action creates a “bubble-netting” that confuses and traps the prey, allowing humpbacks to dive below and lunge upward to feed upon their prey. Like I said, I highly recommend watching this on a video or a documentary because it’s incredible to see, and if you get a chance to see it in person, all the better!
I feel like humpback whales are underappreciated. I first learned about them when I started watching nature documentaries in high school, but it wasn’t until college that they started getting more fleshed out in my mind.
They’re amazing creatures that produce eerily beautiful songs. I should know; I had to listen to some in a lab class in college, and they have a unique feeding behavior for baleen whales. While they’re not endangered or threatened, their populations have been reduced to a fifth of what it once was due to whaling practices—that’s mind-blowing to me!
If what you’ve read has piqued your interest, please take the time to learn more about these creatures. There’s so much that I couldn’t add, and who knows, maybe your curiosity will lead you into a job that will allow you to understand the mysteries of their singing.