Creature: Marine Life

Creatures that primarily inhabit oceans, seas, and other saltwater environments.

Featured Creature: Seahorse

What animal swims upright and is one of the few where males carry the pregnancy?

The seahorse (Hippocampus)!

West Australian Seahorse, Hippocampus subelongatus
Image Credit: J. Martin Crossley via iNaturalist

Introducing Our Spiny Friends

In celebration of my niece’s first birthday, my family and I visited the The New England Aquarium in Boston. As I watched her stare in awe through the glass, taking in all the colors and shapes of various plants and animals, I couldn’t help but tap into my own wonder. Together we brushed the smooth backs of Cownose rays, took in the loud calls of the African penguins, and spent quite a bit of time trying to find the seahorses in their habitats. Eventually we did find them, at the bottom, with their tails curled around bits of seagrass. Now, I already knew a couple details about seahorses: that they were named that way because of their equine appearance, and that they swam vertically. But, crouching there next to my niece, who was looking at them in such curiosity (and confusion), I began to feel…the same way. Why do they curl their tails around plants? Are they tired? How exactly do they eat if they don’t swim around? So when I got home that day I did what any curious person in the 21st century would do, I took to the internet and started learning more about them.

The Small Horses of the Sea

With a long-snouted head and a flexible, well-defined neck reminiscent of that of a horse, the seahorse is aptly named. Its scientific name, Hippocampus, comes from Ancient Greek: hippos, meaning “horse,” and kampos, meaning “sea monster.” In fact, the hippocampus in our brains is named that way because its shape resembles the seahorse.

These creatures can be as small as the nail on your thumb or up to more than a foot long. Out of all 46 species, the smallest seahorse in the world is Satomi’s pygmy seahorse, Hippocampus satomiae. Found in Southeast Asia, it grows to be just over half an inch long. The world’s largest is the Big-belly seahorse, Hippocampus abdominalis, which can reach 35 centimeters long (more than a foot), and is found in the waters off South Australia and New Zealand.

Big-belly Seahorse, H. abdominalis 
(Image Credit: Paul Sorensen via iNaturalist (CC-BY-NC))

Instead of scales like other fish, seahorses have skin stretched over an exoskeleton of bony plates, arranged in rings throughout their bodies. Each species has a crown-like structure on top of its head called a coronet, which acts like a unique identifier, similar to how humans can be distinguished from each other by their fingerprints.

A well-known characteristic of seahorses is that they swim upright. Since they don’t have a caudal (tail) fin, they are particularly poor swimmers, only able to propel themselves with the dorsal fin on their back, and steer with the pectoral fins on either side of their head behind their eyes. Would you have guessed that the slowest moving fish in the world is a seahorse? The dwarf seahorse, Hippocampus zosterae, which grows to an average of 2 to 2.5 centimeters (0.8-1 in.) has a top speed of about 1.5 meters (5 ft.) per hour. Due to their poor swimming capability, seahorses are more likely to be found resting with their tails wound around something stationary like coral, or linking themselves to floating vegetation or (sadly) marine debris to travel long distances. Seahorses are the only type of fish that have these prehensile tails, ones that can grasp or wrap around things. 

Dwarf seahorses in their tank at The New England Aquarium (Photo by author)

How Do Seahorses Eat? By Suction!

Most seahorse species live in the shallow, temperate and tropical waters of seaweed or seagrass beds, mangroves, coral reefs, and estuaries around the world. They are important predators of bottom-dwelling organisms like small crustaceans, tiny fish, and copepods, and they have a particularly excellent strategy to catch and eat prey. As less-than-stellar swimmers, seahorses rely on stealth and camouflage. The shape of their heads helps them move through the water almost silently, which allows them to get really close to their prey.

Denise’s pygmy seahorse, Hippocampus denise
(Jack McKee via iNaturalist
Pimenta via iNaturalist (CC-BY-NC-ND)

Can you find the seahorse in the picture above? As one of the many creatures that have chromatophores, pigment-containing cells that allow them to change color, seahorses mimic the patterns of their surroundings and ambush tiny organisms that come within striking range. They do what’s called pivot-feeding, rotating their trumpet-like snouts at high speed and sucking in their prey. With a predatory kill rate of 90%, I’d say this strategy works. Check out this video below to watch seahorses in action!

Mr. Mom

One of the most interesting characteristics of seahorses is that they flip the script of nature: males are the ones who get pregnant and give birth instead of the females! Before mating, seahorses form pair bonds, swimming alongside each other holding tails, wheeling around in unison, and changing color. They dance with each other for several minutes daily to confirm their partner is alive and well, to reinforce their bond, and to synchronize their reproductive states. When it’s time, the seahorses drift upward snout to snout and mate in the middle of the water, where the female deposits her eggs in the male’s brood pouch.

After carrying them for anywhere between 14-45 days (depending on the species) the eggs hatch in the pouch where the salinity of water is regulated, preparing newborns for life in the sea. Once they’re fully developed (but very small) the male seahorse gives birth to an average of 100-1,000 babies, releasing them into the water to fend for themselves. While the survival rate of seahorse fry is fairly high in comparison to other fish because they’re protected during gestation, less than 0.5% of infants survive to adulthood, explaining the extremely large brood.

White’s seahorse, Hippocampus whitei
(Image Credit: David Harasti via iNaturalist (CC-BY-NC))

A Flagship Species

Alongside sea turtles, seahorses are considered a flagship species: well-known organisms that represent ecosystems, used to raise awareness and support for conservation and helping to protect the habitats they’re found in. As one of the many creatures that generate public interest and support for various conservation efforts in habitats around the world, seahorses have a significant role.

Not only do these creatures act as a symbol for marine conservation, but seahorses also provide us with a unique chance to learn more about reproductive ecology. They are important predators of small crustaceans, tiny fish, and copepods while being crucial prey for invertebrates, fish, sea turtles, seabirds, and marine mammals. 

How Are Seahorses Threatened?

Climate change and pollution are deteriorating coral reefs and seagrass beds and reducing seahorse habitats, but the biggest threat to seahorses is human activities. Overfishing and habitat destruction has reduced seahorse populations significantly. Bycatch in many areas has high cumulative effects on seahorses, with an estimated 37 million creatures being removed annually over 21 countries. Bottom trawling, fisheries, and illegal wildlife trade are all threats to seahorse populations. The removal of seahorses from their habitat alters the food web and disrupts the entire ecosystem, but seahorses are still dried and sold to tourists as street food or keepsakes, or even for pseudo-medicinal purposes in China, Japan, and Korea. They are also illegally caught for the pet trade and home aquariums (even though they fare poorly in captivity, often dying quickly). 

Supporting environmentally responsible fishers and marine protected areas is a great way to start advocating for the ocean and its creatures. Avoiding non-sustainably caught seafood and avoiding purchasing seahorses or products made from them are ways to protect them too.

Project Seahorse, a marine conservation organization, is working to control illegal, unreported, and unregulated (IUU) fishing and wildlife trade for sustainability and legality, end bottom trawling and harmful subsidies, and expand protected areas. The organization also consistently urges the implementation and fulfillment of laws and promises to advance conservation for our global ocean.

The Life We Share

All creatures on this Earth rely on us to make sure the ecosystems they call home are healthy and protected. The ocean is not just an empty expanse of featureless water, but a highly configured biome rich in plants and animals, many of them at risk. So the next time you go to the aquarium and see those little seahorses with their tails wrapped around a piece of grass, remember that we are all part of the same world. Just as these creatures rely on us, we rely on them too.

Abigail

Abigail Gipson is an environmental advocate with a bachelor’s degree in humanitarian studies from Fordham University. Working to protect the natural world and its inhabitants, Abigail is specifically interested in environmental protection, ecosystem-based adaptation, and the intersection of climate change with human rights and animal welfare. She loves autumn, reading, and gardening.

Sources and Further Reading:

Featured Creature: Moon Snail

What seemingly cute, small creature is, in fact, a terrifying killer that drills a hole into their prey, liquifies it, and then sucks it out like a smoothie?

The moon snail (Naticidae)!

Lewis’s Moon Snail, Neverita lewisii (Image Credit: Siobhan O’Neill via iNaturalist)

Have you ever noticed those shells at the beach with perfectly round holes in them? I’ve always wondered how they end up like that. I thought, “surely it is not a coincidence that jewelry-ready shells are left in the sand for a craft-lover like me.” Amazingly, the neat holes are the work of the moon snail.

Take a look at holes made by the moon snail; maybe you’ve seen them before too.

The Small Snowplows of the Ocean

The moon snail is a predatory sea snail from the Naticidae family, named for the half-moon shaped opening on the underside of its globular shell. They are smooth and shiny and come in a variety of colors and patterns depending on the species: white, gray, brown, blue, or orange, with different spiral bands or waves. The size of moon snails also varies by species, ranging from as small as a marble to as large as a baseball. To traverse the ocean floor, moon snails use a big, fleshy foot to burrow through the sand. They pump water into the foot’s hollow sinuses to expand it in front of and over the shell, making it easier to travel along the ocean floor, like a snowplow. (Or should we call it a sand plow?)

Northern Moonsnail, Euspira heros (Image Credit: Cassidy Best via iNaturalist)
Lewis’s Moon Snail, Neverita lewisii (Image Credit: BrewBooks, CC BY-SA 2.0  via Wikimedia Commons)

Moon snails live in various saltwater habitats along the coast of North America. A diversity of species can be found along both the Atlantic Coast between Canada down to North Carolina, and the Pacific Coast from British Columbia down to Baja California, Mexico. They live on silty, sandy substrates at a variety of depths depending on the species, from the intertidal zone and shallow waters below the tidemark to muddy bottoms off the coast 500 meters deep (about 1640 feet, which is greater than the height of the Empire State Building!). You might find a moon snail during a full moon, when the tide is higher and more seashells wash up on shore, plowing through the sand looking for its next meal.

Northern Moonsnail, Euspira heros (Image Credit: Ian Manning via iNaturalist)

When a moon snail fills its muscular foot with water, it can almost cover its entire shell!

Lewis’s Moon Snail, Neverita lewisii (Image Credit: Ed Bierman via Wikimedia Commons)

The moon snail is part of a taxonomic class called Gastropoda, which describes a group of animals that includes snails, slugs, and nudibranchs. The word gastropod comes from Greek and translates to “stomach foot.” The moon snail is a part of this belly-crawler club because it has a foot that runs along the underside of its belly that it uses to get around! 

What’s on the menu? Clam chowder!

What does the moon snail eat? These ocean invertebrates prey primarily on other mollusks that share their habitat, like clams and mussels. They use chemoreception (a process by which organisms respond to chemical stimuli in their environment) to locate a mollusk and envelop it in their inflated foot, dragging it farther into the sand. 

Nearly all gastropods have a radula (think of a tongue with a lot of tiny, sharp teeth) that they use to consume smaller pieces of food or scrape algae off rocks. Moon snails are different. After their prey is captured, moon snails use their radula to grind away at a spot on their prey’s shell. With the help of enzymes and acids secreted from glands on the bottom of their foot, they drill completely through the shell of their victim at a rate of half a millimeter per day. Once the drilling is complete, moon snails inject digestive fluids into the mollusk, liquefying its innards, and slurp up the chowder inside with their tubular proboscis. The entire process takes about four to five days. Vicious, right? And what is even more brutal is that sometimes, moon snails are cannibalistic!

What role does the moon snail play in its environment?

Phytoplankton and algae form the foundation of the marine food web, providing food and energy to the entire ecosystem of sea creatures. Organisms that fall prey to moon snails, like clams and mussels, consume this microscopic algae, as well as other bacteria and plant detritus. The moon snail is a vital link in this interconnected food chain because not only is it important prey for predators like crabs, lobsters, and shorebirds, but it also provides these organisms with energy and key nutrients. Through decomposition, moon snails’ feces, dead bodies, and shells become nutrients for producers like phytoplankton and algae. 

Unfortunately, many things can harm moon snails and their habitats. Meteorological events like hurricanes can cause fluctuations in the species’ abundance. During heatwaves, when record high temperatures combine with extreme low tides like the one in the Pacific Northwest in 2021, moon snails can become extended from their shells, leading to desiccation and death.

The Earth’s temperature has risen at a rate of approximately 0.2°C per decade since 1982, making 2023 the warmest year since global records began in 1850. If yearly greenhouse gas emissions continue to rapidly increase, the global temperature will be at least 5 degrees Fahrenheit warmer and possibly as much as 10.2 degrees warmer by 2100. This continuous increase in temperature puts not just moon snails but humans and the Earth’s biodiversity at large at risk, not only because of more frequent heat waves, but because oceans are becoming more acidic as the water absorbs excess carbon dioxide from the atmosphere. As reporter Hari Sreenivasan explained in the PBS NewsHour report, Acidifying Waters Corrode Northwest Shellfish, ocean acidification affects shellfish a lot like how osteoporosis causes bones to become brittle in humans. The increasing acidity in the ocean reduces the amount of carbonate in the seawater, making it more difficult for moon snails and other shellfish to build and maintain strong calcium carbonate shells.

Colorful Moon Snail, Naticarius canrena (Image Credit: Joe Tomoleoni via iNaturalist)

Human activities also threaten marine creatures like moon snails. Shoreline hardening, aquaculture operations, and water management disturbs the food web and drives species towards extinction. Building structures on the shore to protect against erosion, storm surge, and sea level rise; projects such as geoduck farming; and creating dams and other water diversions disrupts animal communities and results in considerable habitat change. Fortunately, there are environmentally friendly alternatives, like living shorelines. These use plants and other natural features like rocks and shells to stabilize sediments, absorb wave energy, and protect against erosion. 

What can you do to protect these clam-chowing sand plows and the biodiversity of the marine sediment?

Martín Munizaga Kappes via iNaturalist
Clare Kilgour via iNaturalist

One thing you can do to help moon snails is protect their egg casings. In the summer, more moon snails emerge in the shallow, intertidal habitats because it’s time for them to breed. To lay eggs, the female moon snail covers her entire foot in a thick layer of sand that she cements together with mucus. After laying tiny eggs on top, she sandwiches them between another layer of sand and detaches herself from the firm, gelatinous egg mass and leaves them to hatch in a few weeks. These collar-shaped egg casings can sometimes look like pieces of plastic or trash, so make sure you don’t pick them up and throw them away!

Moon snails can be found washed up on dry parts of the beach as well as in submerged parts of sand flats during low tide. If you pick up a moon snail, remember to put it back in the water so it doesn’t dry out in the sun. 

The biodiversity in the marine sediment rivals even coral reefs and tropical rainforests. The organisms that live in this part of the ocean and the services they provide are essential for life on Earth. They cycle nutrients, break down pollutants, filter water, and feed commercial species like cod and scallop that humans eat all the time. Historical fishing activities, bottom trawling, habitat destruction, pollution, climate change, food web modification, and invasive species threaten biodiversity, functions, and services of marine sedimentary habitats. While there are many unknowns and ongoing threats to ocean life, that also means there are more opportunities for research and discovery that can inform effective ocean conservation policies. Supporting these policies that protect oceans and marine life is a way to protect moon snails too.

In ecology, there is a principle that suggests that each ecological niche is occupied by a distinct organism uniquely suited to it. This means organisms exist everywhere, and they have evolved to exist in these places in specific ways. The moon snail’s unique characteristics – notably the way it uses its radula to drill into its prey – shows us that in almost any niche, the organism which occupies it has similarly adapted to optimize its place in that habitat. I’m curious to learn what other unique traits organisms have evolved to adapt to their unique niche.

Off to shell-ebrate the beauty of our oceans and their creatures,

Abigail

Abigail Gipson is an environmental advocate with a bachelor’s degree in humanitarian studies from Fordham University. Working to protect the natural world and its inhabitants, Abigail is specifically interested in environmental protection, ecosystem-based adaptation, and the intersection of climate change with human rights and animal welfare. She loves autumn, reading, and gardening.

Sources and Further Reading:

Conservation Organizations

Articles & Papers

    Featured Creature: Eastern Emerald Elysia

    What creature steals photosynthesis, can go a year without eating, and blurs the animal-plant boundary? 

    The Eastern Emerald Elysia (Elysia chlorotica)!

    Image Credit: Patrick J. Krugg

    “It’s a leaf,” my friend said when I showed her the photograph.

    “Look closely. It’s not a leaf,” I replied.

    “What is it then? Some insect camouflaged as a leaf?” she asked, still staring at the photo.

    “It’s a slug. A sea slug. It starts as an animal and then… becomes plant-like. It steals chloroplasts. It can photosynthesize,” I almost yelled in excitement.

    “What do you mean, it steals chloroplasts? Is there some symbiotic relationship with bacteria that allows it to photosynthesize?” my friend asked—she’s a nature nerd.

    “No, not at all,” I said, feeling overwhelmed. “I don’t quite understand how it works yet. I am not sure anyone truly does.”

    It had only been a few hours since I learned about the Eastern Emerald Elysia (Elysia chlorotica). Since then, I haven’t been able to stop sharing this incredible discovery with anyone who crosses my path—whether they’re interested or not—I’ll share anyway. 

           At first glance, Elysia chlorotica might seem relatively modest. Image Credit: bow_brown_brook via iNaturalist via Maryland Biodiversity 

    Photosynthesis in Nature through Symbiosis

    Days later, as I write, I contemplate my friend’s first instinct. In nature, if you’re not a plant and want to photosynthesize, you usually rely on symbiosis. The first thing that comes to mind are corals. Corals host tiny algae called zooxanthellae within their tissues. The algae photosynthesize,  providing the coral with food and energy in exchange for protection and access to sunlight. 

    But I became curious — What other species in nature photosynthesize through symbiosis? 

    I learned that some sea anemones, sponges, giant clams, hydras and, surprisingly, yellow-spotted salamanders—the only known vertebrate that photosynthesizes—also rely on similar symbiotic relationships, though that’s a story for another time.

    And … lichens, too. 

    In his book Entangled Life: How Fungi Make Our Worlds, biologist and author Merlin Sheldrake describes lichens as “places where an organism unravels into an ecosystem, and where an ecosystem congeals into an organism. They flicker between ‘wholes’ and ‘collections of parts’. Shuttling between the two perspectives is a confusing experience.”

    Indeed, it is a confusing experience. There’s this consistent thread of life forms rejecting the categories we impose on them. Lichens blur the lines between fungi and plants, comprising fungi, algae, and bacteria—organisms from three kingdoms of life, each with a specific ecological role crucial to the whole—a miniature ecosystem. 

    But the Eastern Emerald Elysia (Elysia chlorotica) once more challenges categorization, blurring the lines between the animal and plant world. 

    Where does the animal stop and the plant begin?

    Upon a closer look, Elysia chlorotica proves to be more than ordinary. Transformation in color from brown-reddish to green upon stealing chloroplasts from the Vaucheria litorea algae. The transformation occurs in about 48 hours. Smithsonian Environmental Research Center (CC BY 2.0 via Wikimedia Commons 1, 2, 3)

    Elysia Chlorotica’s Way of Being: Living In Between Worlds 

    I am learning that Elysia chlorotica can be found very close to where I live on the eastern coast of the United States. My friend noted several sightings of them on iNaturalist in states like Massachusetts, Rhode Island, New Jersey, and Connecticut. In fact, the highest concentration of Elysia Chloratica is on Martha’s Vineyard in Massachusetts.  

    Their preferred habitat is shallow tidal marshes and pools with water less than 1.5 feet deep. 

    They are shy, flat, and between 1 and 2 inches long.  

    And although they belong to the clade Sacoglossans, they are often mistaken for Nudibranchs. What differentiates the two is their diet. Nudibranchs are carnivorous, while the Sacoglossans are herbivores. 

    Sacoglossans are also known as sap-sucking slugs due to their feeding behavior. Elysia chlorotica feeds exclusively on the yellow-green macroalga Vaucheria litorea, the two living in close proximity. 

    Selected quote from the video: “It then lives on the food made by these chloroplasts.
    It is a fascinating story of endosymbiosis.”

    The term “feeding” might be a bit misleading. Elysia chlorotica does eat the algae, yet it uses its radula, a specialized set of piercing teeth, to puncture it and suck out all of its contents – “kinda” like a straw. In the process of feeding, it begins to digest everything else, except it leaves the chloroplasts intact – the tiny organelles responsible for photosynthesis in plants.

    The undigested chloroplasts become incorporated into the slug’s digestive tract, visible on its back as a branching pattern that resembles the venation found on a leaf or the structure of our lungs. This process is known as kleptoplasty, derived from the Greek word “klepto,” meaning thief. As chloroplasts accumulate, the slug’s color changes from reddish-brown to green due to the chlorophyll in about 48 hours.

     Karen N. Pelletreau et al., (CC BY 4.0 via Wikimedia Commons)

    When I read this, I engage in a thought exercise—I imagine I am eating a salad. The salad is composed of cucumbers, sesame seeds, and dill (my favorite!) with a bit of olive oil, vinegar, and salt. In the process of eating, I digest everything except the dill, which I leave intact within me. Once the dill gets to my digestive tract, within a matter of 48 hours, I start turning green and gain the ability to photosynthesize—to eat light, to fix CO2, and emit oxygen in return. 

    Of course, this is impossible (or doesn’t yet happen) for humans and animals. Repurposing chloroplasts into one’s physiology, even without digesting them, is a feat that is far from straightforward. It involves complex genes, proteins, and mechanisms—thousands of them—ensuring that this process functions correctly. There’s a precise interaction, akin to a lock-and-key mechanism, that makes this extraordinary adaptation possible. It is more of a dialogue, an evolutionary dialogue—an activation. 

    What is even more extraordinary is that Elysia chlorotica can maintain functioning chloroplasts for its entire life cycle, approximately 12 months. It only needs to eat once. Normally, chloroplasts need a lot of support from the plant’s own genes to keep functioning. When they are inside an animal cell, they are far from their original plant environment. And one cannot ignore the immune system, which upon sensing a foreign body, should initiate an attack. 

    This intrigues scientists. For example, there are many other species that are kleptoplasts, including a few other Sacoglossans sea slugs. I learned that some ciliates and foraminiferans are, too. And there’s a marine flatworm that can steal chloroplasts from diatoms. 

    However, none of them can maintain intact chloroplasts as long as Elysia chlorotica. 

    At first you might have been surprised by just how it incorporates plant-like processes into an animal body. But then the question transforms into how it maintains these processes. Maintenance, it seems, is still a mystery. And for what? 

    For a more in-depth exploration of Elysia chlorotica, watch this video and
    refer to its description for scientific papers and additional readings.

    Yet What is This Chloroplast Maintenance For? Does It Need Photosynthesis to Survive? 

    From the video above that does an excellent job summarizing various scientific discoveries and Ed Yong’s article “Solar-Powered Slugs Are Not Solar-Powered,” I was able to understand the development of a mental model and the nature of scientific inquiry through experimentation and challenging assumptions surrounding the sea slug. 

    Initially: It was believed that Elysia chlorotica stole chloroplasts and relied entirely on photosynthesis for survival.

    Then: It was found that sunlight isn’t crucial for its survival—starvation, light or darkness–it doesn’t matter.

    Finally: Research on other species of sea slugs Elysia timida and Plakobranchus ocellatus showed that while these slugs convert CO2 into sugars in the presence of light, they don’t need photosynthesis to survive. They concluded that chloroplasts might act as a food reserve, hoarded for future needs.

    However: The mystery remains of how chloroplasts perform photosynthesis in an animal body. The hypothesis that chloroplasts function due to gene theft was disproven. Chloroplasts need thousands of genes, mostly from the host cell’s nucleus, but that is left behind during chloroplast theft. Nobody truly understands how the chloroplasts continue to function under these conditions. 

    I’m left confused, moving from thinking photosynthesis was essential to realizing it’s not required for survival, yet chloroplasts still perform photosynthesis. 

    If you also feel confused, please know, this uncertainty and surrendering to the unknown is crucial when studying and learning from the natural world. Questions like ‘why they need photosynthesis at all’ and ‘how it happens’ remain unanswered. 

    Due to the difficulty of raising Elysia chlorotica in the lab, and the need to carefully limit their collection to protect wild populations, research on them is highly challenging. Climate change and habitat fragmentation make this task even more difficult.

    I look forward to following the progress of this research and am grateful to the scientists who continue to push boundaries and deepen our understanding of these remarkable creatures. This is one more example of why it is so important to protect and restore the Earth’s ecosystems.  

    The Genesis of Symbiosis. The Origin of The Chloroplast. The Becoming of the Earth.

    Researching Elysia chlorotica took me on an entirely different path. I have always been interested in the origin of things, how something emerges, and the question of what is the origin of the chloroplasts intuitively unfolded. 

    I tried to understand symbiosis as defined by evolutionary biologist Lynn Margulis. At the recommendation of Bio4Climate staff biologist Jim Laurie, I watched (and then re-watched) the documentary Symbiotic Earth: How Lynn Margulis Rocked The Boat and Started a Scientific Revolution.

    It led me to Symbiogenesis. Symbiogenesis, as defined by Lynn Margulis, is the theory that new organisms and complex features evolve through symbiotic relationships, where one organism engulfs and integrates another. 

    In a moment of serendipity, I was surprised to see in one of the scenes in the documentary that the Elysia chlorotica was on the cover of the book titled “Symbiogenesis: A New Principle of Evolution” by Boris Mikhaylovich Kozo-Polyanksy. One of its editors is Lynn Margulis. 

    Photograph I took of a projected scene from the documentary Symbiotic Earth: How Lynn Margulis Rocked the Boat and Started a Scientific Revolution.

    I never considered the genesis of symbiosis before–its connection with the genesis of life on Earth as we know it and with the biogeochemical cycles, fundamental processes that make our planet habitable. 

    This serendipitous moment, coupled with my learning process of Elysia chlorotica feels like some sort of beginning for me–a new understanding of how to perceive the becoming of the Earth.

    Lynn Margulis, through her Serial Endosymbiotic Theory (SET), proposed that chloroplasts and mitochondria were originally free-living bacteria that entered into symbiotic relationships. 

    I am becoming aware that these primordial organelles have been integral to life’s evolution, part of a biological legacy that has shaped the Earth’s emergence of life for billions of years. And it all started with bacteria! 

    Elysia chlorotica, with its ability to steal chloroplasts, has reminded me that when studying the natural world, there is always something that doesn’t quite fit into our predetermined categories of knowledge and that life inevitably discovers a way to persist through new configurations of interacting and being.

    We now understand that classifying nature goes beyond just physical appearances. There are hidden processes at play—molecular, genetic, and biogeochemical—that allow us to trace the origins of life and understand it in ways that extend beyond mere morphology. Nature, ultimately, defies rules—this seems to be the only rule. The once-ordered tree of life gives way to fluid boundaries and intricate entanglements. This emerging complexity reflects the true essence of life: dynamic, interconnected, ever-evolving, filled with irregular rhythms.

    And now, I have a new category, a new lens through which to perceive nature: “Animals That Can Photosynthesize.” (hear Lynn Margulis talk about this topic in the first 10 minutes of the podcast). 

    Left: Chloroplasts. Photo Credit: Kristian Peters-Fabelfroh (CC BY-SA 3.0 via Wikimedia Commons)
    Right: Project Apollo Archive (Public Domain via Wikimedia Commons)

    Without chloroplasts, there would be no plants, sea slugs, and oxygen-rich Earth. And without cyanobacteria—the believed progenitors of chloroplasts—much of the life we know of today, and perhaps countless other forms yet to be discovered, would not exist.

    I hope you can look beyond the form of living systems and envision how life emerged through symbiosis. 

    Picture this emergence on various scales, from the microscopic chloroplast to the scale of an entire planet.

    With gratitude, yet green with chloroplast envy, 

    Alexandra

    Alexandra Ionescu is an Ecological Artist and Certified Biomimicry Professional. She currently works at Bio4Climate as the Associate Director of Regenerative Projects, focusing on the Miyawaki Forest Program. Her aim is to inspire learning from and about diverse non-human intelligences, cultivating propensities for ecosystem regeneration through co-existence, collaboration and by making the invisible visible. She hopes to motivate others to ask “How can humans give back to the web of life?” by raising awareness of biodiversity and natural cycles to challenge human-centric infrastructures. In her spare time, Alexandra is part of the Below and Above Collective, an interdisciplinary group that combines art with ecological functionality to construct floating wetlands and is a 2024 Curatorial Fellow with Creature Conserve where she organized a webinar and “Read/Reflect/Create” club centered on beavers.

    Sources and Further Reading:

    Videos

    Articles

    Scientific Papers

    Featured Creature: Coelacanth

    What 200-pound nocturnal sea creature, thought to be extinct for millions of years, has one of the longest gestation periods among vertebrates? 

    The Coelacanth!

    Bruce A.S. Henderson (Wikimedia Commons)

    This sea creature was thought to be extinct for 65 million years before it was rediscovered in 1938. Ancient and rare, the coelacanth is a fish so named from its fossil. Scientists knew this fish once existed but never expected to find it alive in the depths of the ocean. The coelacanth (pronounced seel-a-canth) is about 200 pounds and can grow to over 6.5 feet in length.  Two species exist today – the Indonesian coelacanth (Latimeria menadoensis)  and the African coelacanth (Latimeria chalumnae).

    Anatomy

    Coelacanth is derived from Latin and means “hollow spine” due to their hollow caudal fin rays. They have thick scales giving them an ancient appearance.These fish lack boney vertebrae. Instead, they have a notochord which is a fluid-filled rod beneath the spinal cord. Coelacanths also use a rostral organ to detect the electrical impulses of nearby prey much like stingrays and sharks. Most distinctive is the coelacanth’s limb-like pectoral fins that appear more like an arm than a fin. The coelacanth has a very unique anatomy. No other fish on Earth possesses these special features. 

    Ji-Elle (CC BY-SA 3.0 via Wikimedia Commons)

    Diet

    The next discovery of a live coelacanth came in 1952 – 14 years after the first revelation. But why did it take so long for another fish to be caught? Coelacanths live at great very deep depths, often over 500 feet beneath the surface of the ocean. When they venture into shallower waters, they tend to do so at night. Coelacanths are nocturnal predators.They hide under rock formations and in caves until nightfall when they emerge to hunt other fish, crabs, eels, and squid.They use their hinged skull which enlarges their gape to swallow prey.

    Population

    The IUCN has listed the coelacanth as critically endangered. It is estimated that only 500 coelacanths exist today. Although not considered an edible fish, as its meat is too oily for consumption, the coelacanth still falls prey to deep-sea fishing nets. If caught as by-catch, coelacanths can die from the stress. These threats can deeply affect the population because coelacanths have an unusually long gestation period of three years – the longest of any vertebrate species. Such factors make coelacanths extremely vulnerable to extinction. 

    Dean Falk Schnabel (CC BY-SA 4.0 via Wikimedia Commons)

    The story of the coelacanth proves there is always more to discover. Biodiversity fosters a sense of curiosity about the endless possibilities of the natural world.

    I wonder, if a creature like this still exists, what other species remain unknown to humanity?

    Swimming away for now, Joely

    Joely Hart is a wildlife enthusiast writing to inspire curiosity about Earth’s creatures. She holds a Bachelor’s degree in creative writing from the University of Central Florida and has a special interest in obscure, lesser-known species.

    Sources and Further Reading:
    https://a-z-animals.com/animals/mouse-deer-chevrotain
    https://www.khaosok.com/national-park/mouse-deer
    https://www.ultimateungulate.com/Artiodactyla/Hyemoschus_aquaticus.html
    https://factanimal.com/chevrotain/
    https://www.npr.org/2019/11/11/778312670/silver-backed-chevrotain-with-fangs-and-hooves-photographed-in-wild-for-first-ti

    Featured Creature: Blue Whale

    Which creature who helps fight climate change has newborns the size of an adult elephant and is not a fan of boats?

    The Blue Whale!

    Photo from National Marine Sanctuaries (via Wikimedia Commons)

    Big, bigger, and biggest

    Blue whales are the largest creature to ever grace this Earth. They can grow to around 100 ft (33 meters), which is more than twice the size of a T-Rex dinosaur! Newborn calves are around the same size as an adult African elephant – about 23 ft (7 meters). To get more of an idea of how huge these animals are, picture this: a blue whale’s heart is the size of a car, and their blood vessels are so wide a person can swim through them!

    Despite their large size, blue whales eat tiny organisms. Their favorite food is krill, small shrimp-like creatures. They can eat up to 40 million of these every day. They do so by opening their mouths really wide, and after getting a mouthful, they’ll close their mouths and force out the swallowed water with their tongue, while trapping the krill behind their baleen plates – this method is known as filter feeding.

    Photo by Don Ramey Logan (CC BY-SA 3.0 via Wikimedia Commons)

    From coast to coast

    Blue whales live in every ocean except the Arctic. They usually travel alone or in small groups of up to four, but when there are plenty of krill to go around, more than 60 of these mega-creatures will gather around and feast. 

    Blue whales can communicate across 1,000 miles (over 1600 km)! Their calls are loud and deep, reaching up to 188 decibels – so loud that it would be too painful for human ears to bear. Scientists believe that these calls produce sonar – helping the whales navigate through dark ocean depths.

    Climate Regulator

    All that krill has to go somewhere, meaning out the other end. Whale poop helps maintain the health of oceans by fertilizing microscopic plankton. Plankton is the bedrock of all sea life, as it feeds the smallest of critters, and these critters then feed larger creatures (and on goes the food chain). Plankton include algae and cyanobacteria that get their energy through photosynthesis, and they are abundant throughout Earth’s oceans. These microorganisms contribute to carbon storage by promoting the cycling of carbon in the ocean, rather than its emission in the form of carbon dioxide.  Without whales, we wouldn’t have as much plankton, and without plankton, the food cycle would collapse, and more gas would rise to the atmosphere. Therefore, whale poop acts as a climate stabilizer.

    Learn more about this whale-based nutrient cycle here:

    Size doesn’t equal protection

    Unfortunately, the sheer size of blue whales isn’t enough to prevent them from harm. Blue whales were heavily hunted until last century, and although a global ban was imposed in 1966, they are still considered endangered. 

    Today, blue whales must navigate large and cumbersome fishing gear. When they get entangled, the gear attached to them can cause severe injury. Dragging all that gear adds a lot of weight, so this also zaps their energy sources. Since blue whales communicate through calls intended to travel long distances, increased ocean noise either from ships or underwater military tests can also disrupt their natural behaviors. 

    Another threat blue whales face are vessel strikes. They can swim up to 20 miles an hour, but only for short bursts. Usually, blue whales travel at a steady pace of 5 miles per hour. This means that they aren’t fast enough to dodge incoming vessels, and these collisions can lead to injuries or even death for the whales. In areas where traffic is high, such as ports and shipping lanes, this threat becomes even more prominent.

    To protect blue whales, and our oceans, we can implement sustainable fishing practices that use marine mammal-friendly gear. We can also reduce man-made noise, and utilize precautionary measures when venturing out to sea. That way we avoid vessel strikes and have a higher chance of witnessing the largest creature to ever grace our planet.

    For creatures big, bigger, and biggest,
    Tania

    Tania graduated from Tufts University with a Master of Science in Animals and Public Policy. Her academic research projects focused on wildlife conservation efforts, and the impacts that human activities have on wild habitats. As a writer and activist, Tania emphasizes the connections between planet, human, and animal health. She is a co-founder of the podcast Closing the Gap, and works on outreach and communications for Sustainable Harvest International. She loves hiking, snorkeling, and advocating for social justice.

    Sources and Further Reading:
    https://us.whales.org/whales-dolphins/facts-about-blue-whales/
    https://www.natgeokids.com/uk/discover/animals/sea-life/10-blue-whale-facts/
    https://www.fisheries.noaa.gov/species/blue-whale 
    https://www.greatwhaleconservancy.org/how-whales-help-the-ocean

    Featured Creature: Banded Sea Krait

    What semiaquatic creature has a paddle-like tail, swims through crevices, and can even climb trees?

    The banded sea krait!

    Photo by Bernard Dupont, CC BY-SA 2.0 via Wikimedia Commons

    Did you know that some snakes can swim? Beyond the legends of mighty and fearsome sea serpents, sea snakes exist, and swim through waters around the world, not just the pages of myth and folklore. 

    The banded sea krait is a type of sea snake that inhabits the Pacific and Indian Oceans. Males are about 30 inches long, while females can be up to 50 inches long. As the name may hint, the banded sea krait’s bluish-gray body is scored by thick, dark blue bands numbering from 20 to 65. The top half of its body is colored more darkly than its underside, a kind of pigmentation called countershading unique to many sea creatures. Countershading is a type of aquatic camouflage that helps the sea krait blend in with its environment, an adaptation that contributes to these creatures’ survival.

    By appearing dark from above, the sea krait becomes challenging to differentiate from the water. By appearing lighter from below, it melds with the sunlight of shallow water. This makes it difficult for predatory birds to spot the sea krait from the sky and conceals the reptile from prey watching below.

    The banded sea krait boasts a specialized tail shaped like a paddle that enables it to swim quickly through the water. These creatures also have valved nostrils to keep out water when diving. Despite spending most of its life in the ocean, the banded sea krait lacks gills and must breathe air. However, it can hold its breath for up to 30 minutes. A unique organ called the saccular lung helps banded sea kraits take in more oxygen when they come up for air. This lung acts like a diver’s oxygen tank. 

    Photo by Matt Berger, CC BY 4.0 via Wikimedia Commons

    Formidable Feeding Habits

    The banded sea krait hunts fish and eels. Its cylindrical body easily weaves through coral reefs and mangrove roots to reach the hiding spots of its prey. Females are up to three times larger than males and prefer to hunt Conger eels due to their size while males often select the smaller Moray eel. Like terrestrial snakes, banded sea kraits swallow their prey whole and can consume eels much larger than themselves. Such a massive meal hinders the ability to swim properly, so the krait must come ashore to digest. This digestion process can take weeks to finish. Talk about a satisfying meal!

    Amphibious Nature

    Banded sea kraits venture on land to digest food, shed skin, drink freshwater, and lay eggs. They spend about 25% of their time on islands, mangrove forests, or rocky inlets and the rest in the sea. Despite their paddle-like tail better suited for swimming, they travel remarkably well on land, and have even been observed climbing trees. 

    Banded sea kraits use rocks to shelter beneath while waiting to digest their food and to rub against to help shed their skin. These reptiles must consume freshwater to survive and find lakes, streams, or puddles of rainwater on land to drink. When it comes to reproduction, eggs are laid under the sand by female banded sea kraits.

    Photo by Matt Berger, CC BY 4.0 via Wikimedia Commons

    Venom

    Banded sea kraits are highly venomous. They inject venom through their fangs, and itis 10 times more potent than a rattlesnake’s! This comes in handy when it’s time to hunt. A banded sea krait may hide among coral crevices and wait to strike a passing eel. Its venom works quickly to paralyze the prey. 

    Don’t be alarmed – humans are rarely bitten by these kraits, as they have a very docile and non-confrontational nature. Some people, mostly fishermen hauling up nets, have been bitten in the past (symptoms include seizures, muscle paralysis, and respiratory failure). 

    Life Cycle

    Aside from their other land-based activities, female banded sea kraits come ashore to lay eggs. They may lay between 5 – 20 eggs, which then hatch in about 4 months. Babies emerge fully capable of surviving the ocean environment and appear as miniature versions of the adult banded sea krait. They will hunt smaller prey until they grow larger enough to take on eels. Banded sea kraits are estimated to live for 20 years in the wild.

    Take a look at some of their activities in action: 

    And if you’re wondering how a sea krait can swallow an eel whole, watch this video:

    From well-recognized animals like the humpback whale and dolphin to the lesser known banded sea krait, the ocean is a haven rich in biodiversity.

    Swimming away for now,
    Joely

    Joely Hart is a wildlife enthusiast writing to inspire curiosity about Earth’s creatures. She holds a Bachelor’s degree in creative writing from the University of Central Florida and has a special interest in obscure, lesser-known species.

    Sources and Further Reading:
    https://earthsky.org/earth/lifeform-of-the-week-banded-sea-krait-is-a-two-headed-swimming-snake/
    https://animaldiversity.org/accounts/Laticauda_colubrina
    https://oceana.org/marine-life/banded-sea-krait/
    https://www.dovemed.com/diseases-conditions/common-yellow-lipped-sea-krait-bite

    Featured Creature: Atlantic Puffin

    What striking seabird is a master of adaptability in the ocean and the air? 

    The Atlantic Puffin!

    Image by Anne-Ed C. from Pixabay

    Nestled around the edges of the North Atlantic, the Atlantic Puffin, or Fratercula arctica, is a seabird of great charm and adaptability. Resembling a penguin in its coloration, yet distinguished by its multicolored and uniquely shaped bill, this captivating creature is often affectionately dubbed the “sea parrot.” 

    Atlantic puffins have also been known as “sea clowns” because of that funky flattened bill, but make no mistake – these are some seriously impressive seabirds. With sophisticated burrows, skillful hunting, and dedication to raising families with determined care, these bright birds are marvels of the ocean.

    Image by Mario from Pixabay

    Aquatic Aviators

    Atlantic puffins spend the majority of their lives navigating the vast expanse of the North Atlantic, where they are found on islands and coastal shores from North America to Scandinavia. With wings that double as paddles, they can “fly” through the water, propelled by powerful flippers and webbed feet.

    These adept swimmers dive to impressive depths of up to 200 feet, hunting small fish like sand eels and herring with remarkable precision. In addition to their aquatic prowess, puffins can also fly, though they are unable to soar like other broad winged seabirds. Instead, using wings that can flap up to 400 times per minute, Atlantic puffins are able to reach speeds of up to 55 miles per hour (88.5 km/h).

    Image by Decokon from Pixabay

    Family Life

    During the breeding season, thousands of puffins gather in colonies along the coasts and islands of the North Atlantic. These colonies provide safety in numbers, shielding the birds from larger predators like skuas and gulls that patrol the skies above. The breeding season sees puffins at their most colorful, with those distinctive bills featuring their blue-gray triangles accented in bright yellow. When the season is over, the bills’ outermost layers actually molt, and revert to a partly gray and partly orange color combination. 

    Puffins exhibit strong pair bonds, often forming lifelong partnerships with their mates. They engage in affectionate behaviors such as rubbing and tapping beaks, reinforcing their bond year after year. Remarkably, these avian couples frequently return to the same burrow to raise their young each season.

    Using their beaks and claws, they construct deep burrows that nestle between rocky crags and crevices. These generally feature separate tunnels that are used as a bathroom area, and a main nesting chamber that serves as a safe haven for incubating eggs, which hatch after a period of 42 days. 

    Pufflings, as these chicks are called, are adorned with fluffy feathers that will eventually facilitate their ability to swim and fly. Both parents play an active role in incubating the egg and caring for their offspring once it has hatched, fetching food for the young puffling with skill and dedication. They make use of a unique adaptation of small spines along their bills, tongues, and the roofs of their mouths that allow them to hold bunches of fish in place as they fly from their hunts on open waters back to the nests where their young ones wait. It is estimated that during the time a puffling stays in its burrow dependent on this care, its parents will make close to 12,400 dives total to keep up the steady supply of food.

    Image by Simon Marlow from Pixabay

    Persevering Under Threat

    Despite their remarkable adaptability, Atlantic puffins face a number of challenges in the modern world. From habitat loss and predation to climate change and human disturbances, these beloved seabirds are confronted with an uncertain future, and they are currently classified as Vulnerable by the IUCN (International Union for Conservation of Nature). In particular, as ocean temperatures rise and fish populations decline or shift their habitat, puffins struggle to find food with enough frequency and reliability to get by. Conservation and restoration measures can help ease these pressures by preventing overfishing, ensuring abundant marine ecosystems, and allowing all forms of ocean life, from underwater critters to seabirds, to survive and adapt. While the intersecting challenges of a warming and increasingly chaotic planet may be complex, modifying human behaviors has made a tremendous difference for these colorful creatures before. 

    Take a look at the story of their bounce back from near extinction in the 20th century:

    May we take hope in our power to shape our planet’s future for the better, and show the same love and dedication to these sweet seabirds as they do to their young pufflings. 

    Flapping away now,

    Maya

    Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

    Sources and Further Reading:
    https://www.allaboutbirds.org/guide/Atlantic_Puffin/overview#
    https://www.nationalgeographic.com/animals/birds/facts/atlantic-puffin
    https://kids.nationalgeographic.com/animals/birds/facts/atlantic-puffin
    https://www.audubon.org/field-guide/bird/atlantic-puffin
    https://abcbirds.org/bird/atlantic-puffin/
    https://www.science.org/content/article/watch-puffin-use-tool-scratch-itch
    Recent changes in the diet and survival of Atlantic puffin chicks in the face of climate change and commercial fishing in midcoast Maine, USA. Stephen W. Kress, Paula Shannon, Christopher O’Neal. FACETS 21 April 2016. https://doi.org/10.1139/facets-2015-0009

    Featured Creature: Flamingo

    What long-legged creatures are known for their beauty, social habits, and fabulous flamboyance?

    Flamingos!

    Image by Alexa from Pixabay

    Flamingos are among the most recognizable birds in the world. These long-legged wading birds are known for their vibrant pink plumage and distinctive S-shaped necks, and rank among the most iconic inhabitants of wetlands across the globe. 

    They are known to congregate in large flocks, standing (often perched on one leg) in the shallows of their habitat. Given their unmistakably flashy appearance, it is apt that a group of flamingos is known as a “flamboyance.”

    Image by Gunnar Mallon from Pixabay

    Flamingos boast a slender body, stilt-like legs, and a characteristic downward-bending bill, making them instantly recognizable. Though they are most often depicted as a bright pink, their plumage ranges from a subtle pink to crimson. This hue is actually derived from carotenoid pigments found in their diet of algae, crustaceans, and small invertebrates. So as flamingos’ range and available food sources vary, so too might their color. Interestingly, this same pigment responsible for the flamingo’s iconic pink is also what makes carrots orange and ripened tomatoes red. 

    Flamingos thrive in saline or alkaline lakes, mudflats, and shallow lagoons, where they feed on algae, invertebrates, larvae, small seeds, and crustaceans like brine shrimp. Their long legs enable them to wade into deeper waters, utilizing their uniquely adapted bills to filter food from the mud and water. In fact, though the term usually calls to mind creatures like oysters or whales, flamingos are also considered “filter feeders” in their behavior and diet.

    Image by Paul from Pixabay 

    While most flamingo species are not endangered, habitat loss and human activities pose significant threats to their populations. Conservation initiatives, such as the establishment of protected reserves and the monitoring of wild populations, are crucial for safeguarding these charismatic birds and their habitats. As indicators of environmental health and key feeders in the wetlands, flamingos play a vital role in maintaining the delicate balance of their ecosystems. 

    Lifestyle and relationships

    Flamingos are highly social creatures, forming large flocks that can number in the thousands. They engage in intricate mating displays and rituals, characterized by synchronized movements and vocalizations. Once a couple has chosen to mate, breeding pairs construct simple mud nests, where they raise their offspring, feeding them a specialized “crop milk” produced in their upper digestive tract.

    With a lifespan of 20 to 30 years in the wild, and up to 50 years in captivity, flamingos exhibit remarkable longevity. They typically lay a single chalky-white egg, which both parents incubate and care for until hatching. Young flamingos, born with gray downy feathers, gradually develop their iconic pink plumage over time.

    Image by Pfüderi from Pixabay

    Over time, these bright birds form strong social bonds that characterize their lives and behaviors. Remarkably, it has been observed that some flamingos will make friends for decades. Researchers have speculated that the bonds, which are influenced by factors such as personality traits and physical characteristics, may aid survival.

    This long lasting affinity has led to comparisons and speculations about different forms of love in the animal kingdom. Though we see lots of courtship, pairing, and even mating for life in different species, friendship is one of those underrated forms of love well worth celebrating. And while these social relationships may indeed help with survival, it also might just be true that life is better with friends by your side.  

    Feeling the love,

    Maya

    Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

    Sources and Further Reading:
    https://animals.sandiegozoo.org/animals/flamingo
    https://kids.nationalgeographic.com/animals/birds/facts/flamingo
    https://nationalzoo.si.edu/animals/american-flamingo
    https://www.audubon.org/birds-of-america/american-flamingo
    https://www.nationalgeographic.com/animals/article/flamingos-make-friends-for-life
    https://nationalzoo.si.edu/animals/news/why-are-flamingos-pink-and-other-flamingo-facts

    Featured Creature: Humpback Whale

    What species of tremendous size and grace undertakes the largest mammal migration on Earth? 

    The humpback whale!

    Image by Brigitte Werner from Pixabay

    In the vast expanses of the world’s oceans, a symphony of moans, cries, and howls fills the water, echoing across great distances. This stunning serenade is the song of the humpback whale, one of the most majestic creatures to grace the seas. 

    Scientifically known as Megaptera novaeangliae, the humpback whale derives its common name from the distinctive hump on its back. With dark backs, light bellies, and long pectoral fins that resemble wings, these whales are a sight to behold. Their Latin name, signifying “big wing of New England,” pays homage to those impressive pectoral fins and early encounters European whalers had with these graceful giants off the coast of New England. 

    Image by Monica Max West from Pixabay

    Humpback whales are renowned for their enchanting songs, which echo through the ocean depths for great distances. These compositions, which consist of moans, howls, and cries, are among the longest and most complex in the animal kingdom. Scientists speculate that these melodic masterpieces serve as a means of communication and courtship, with male humpbacks serenading potential mates during the breeding season for minutes to hours at a time. Songs have also been observed during coastal migrations and hunts. Many artists have taken inspiration from these songs, and you can even listen to eight-hour mixes of them to help you get to sleep. Check it out:

    Another marvel of the humpback are their awe-inspiring displays of acrobatics, from flipper slapping to full-body breaching. Despite their colossal size, these creatures display remarkable agility and grace. With lengths of up to 62.5 feet (19m, or one school bus!) and weights of 40 tons (40,000 kg), humpback whales are true behemoths of the ocean.

    Life on the move

    Life for a humpback whale is a tale of two halves—a perpetual journey between polar feeding grounds and tropical breeding waters. These remarkable migrations span thousands of miles and rank as one of the longest animal migrations on the planet, and the longest among mammals. 

    Feasting on plankton, krill, and small schooling fish, humpback whales are skilled hunters, capable of consuming up to 1,360 kilograms of food per day. Employing innovative techniques such as bubble-netting and kick-feeding, they ensnare their prey with precision and efficiency. Generally these whales stay in small and dynamic groups, and they use their social intelligence and coordination to orchestrate these group hunting mechanisms. 

    Ecological powerhouses

    Humpback whales’ feeding and movement contributes to more than just their own wellbeing. As these majestic creatures feed on zooplankton, copepods, and other food sources in the oceans’ depths, and subsequently ascend to the surface, they disrupt the thermocline—a boundary between surface and deep waters—facilitating greater mixing of ocean layers. This enhanced mixing fosters increased nutrient availability, benefiting a myriad of marine organisms. 

    They also cycle nutrients through their own consumption and excretion, contributing to a phenomenon known as the “biological pump.” These whales ingest biomass and nutrients from microscopic and small macroscopic organisms in deeper waters, digest it, and excrete their own waste in large macroscopic fecal plumes on the ocean’s surface. This cyclical process effectively transports nutrients from the ocean depths back to the surface, replenishing vital elements such as nitrogen for algae and phytoplankton growth. In regions like the Gulf of Maine, the nitrogen influx from whale feces surpasses that of all nearby rivers combined, underscoring the profound impact of these marine giants on nutrient cycling. Finally, when a whale’s life has come to an end, its own massive body sinks to the ocean floor and countless organisms are nourished by it in the decomposition process.

    Image by shadowfaxone from Pixabay

    Conservation and Resurgence

    Understanding the multifaceted lives and roles of humpback whales underscores the urgency of their conservation. Historically valued solely for commercial exploitation, these majestic creatures now emerge as essential components of oceanic ecosystems. Though humpback whales have faced centuries of exploitation and habitat degradation, concerted conservation efforts offer hope for their survival, not only safeguarding whales themselves but also preserving the intricate ecological processes that sustain marine life and biodiversity. 

    Whales continue to face threats from ship collisions, entanglement in fishing gear, noise pollution, and the disruption of habitat for their food sources due to trawling, pollution, and encroachment. But strong advocacy has brought these creatures back from the brink before, and our conservation and restoration work can safeguard the future of these enchanting giants and ensure that their songs continue to echo through the seas for generations to come.

    Take a look at Sir David Attenborough’s tale of their resurgence and beauty:

    May we steward the ocean with love and care,

    Maya

    Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

    Sources and Further Reading:
    https://www.fisheries.noaa.gov/species/humpback-whale
    https://www.nationalgeographic.com/animals/mammals/facts/humpback-whale
    https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Humpback-Whale
    https://us.whales.org/whales-dolphins/species-guide/humpback-whale/
    https://www.pbs.org/wnet/nature/blog/humpback-whale-fact-sheet/
    https://conservationconnections.blogspot.com/2012/05/importance-of-whale-poop-interview-with.html
    https://www.youtube.com/watch?v=uRY9giOUTrI (Whales as Keystone Species – Cycling Nutrients, Carbon and Heat with Joe Roman at Bio4Climate’s Restoring Oceans conference)

    Featured Creature: Whale Shark

    What creature is the largest of its kind, sports beautiful patterns, and holds a reputation for being a ‘gentle giant’? 

    The whale shark!

    Photo by Shiyam ElkCloner (CC BY-SA 3.0 via Wikimedia Commons)

    Filter feeding for giants 

    The majestic whale shark is famed for being the largest fish in existence. With a length of up to 33 feet and weight up to 20 tons, they are not only the largest living fish, but thought to be the largest fish that ever lived on this planet. Though their name might suggest otherwise, whale sharks are not a type of whale at all, but instead a member of the shark family. It is their enormous size (akin to a school bus) that led them to be compared with whales. 

    Like their other shark relatives, these creatures are excellent swimmers and true masters of the deep. People are coming to recognize that all sharks, even carnivorous species that hunt marine mammals, fish, or other invertebrates, have been unfairly mischaracterized as threatening, and whale sharks are another species you need not be afraid of. 

    In fact, one of the most fascinating traits of the whale shark is its diet. Despite their own large size, whale sharks subsist on some of the smallest ocean inhabitants, plankton. Much like the enormous blue whale, whale sharks are a living example of one of the most interesting links in the food chain, where nutrients are cycled from microscopic life to macroscopic organisms. 

    They filter-feed by opening their mouths and letting plankton-rich waters pass through, as well as ingesting other small fish or unlucky invertebrates along the way. But even in this habit they are unique. Whale sharks use a technique called “cross-flow filtration,” in which particles do not actually catch on the filter (the way it works when we drain pasta through a strainer or breathe through an N95 mask). Instead, water is directed away through the gills while particles move towards the back of the mouth. A bolus (or a spinning ball of food) grows in size as more particles are concentrated, finally triggering a swallowing reflex in the throat. This avoids clogging any filters in the process and is a particularly efficient method of filter feeding. 

    Because they are so large, whale sharks need a lot of food to sustain themselves, and so they journey long distances in order to eat enough for their great big appetites. They can be observed throughout the world in warm tropical waters and tend to lead solitary lives. Where there is an abundance of plankton, however, whale sharks are sure to follow. For example, in the Springtime many whale sharks migrate to the continental shelf of the Central West Coast of Australia, where Ningaloo Reef is the site of a great coral spawning that produces water rich with plankton for our giant fishy friends to enjoy.

    Photo by Leonardo Lamas from Pexels

    Big fish in a complex sea

    The whale shark contributes to nutrient cycling throughout its lifespan, providing important benefits to the ecosystems they are a part of. Some of the warm tropical waters that whale sharks call home tend to be low in nutrients and productivity, and in these areas whale sharks can make a big difference due to their size and force. As they undertake migrations or even as they go about daily swimming and feeding activities, their motion stimulates small ocean currents that can help nutrients travel from areas of high productivity to waters where they are much less concentrated. 

    Their own eating habits rely on an abundance of microscopic creatures and the nutrients they metabolize, and eventually each mighty whale shark passes on and becomes food itself, returning those nutrients to the ocean food web. After death, whale sharks sink to the ocean floor and the benthic organisms that reside there find food and shelter in the great carcasses. It can take decades for this decomposition to occur, and in the meantime hundreds of creatures benefit from the habitat and nutrients left behind.  

    In life as well, whale sharks can provide refuge to smaller species of fish that travel around their great bodies, taking advantage of the shelter these gentle giants create. As largely docile creatures, whale sharks can be quite approachable and playful with divers who are also interested in tagging along: 

    In a couple of instances, humans have even pushed their luck so far as to ride along on a whale shark’s back! Such close contact is discouraged by conservationists to protect the personal space of these beautiful animals, but whale sharks’ friendly reputation remains. 

    Though they may be steady, generous members of the ocean community, whale sharks are struggling to survive in changing conditions. They are an endangered species, and while some protections for these creatures have been enacted across the coastal waters of the world, they are still hunted for meat, fins, and oil, or captured or killed as bycatch in industrial fishing operations. Whale sharks also suffer from the plastic pollution in our oceans, as microplastics mingle with the food they rely on. Like the rest of us, whale sharks need clean, healthy, abundant environments in which to live and co-create. 

    Whale shark in the Maldives (Photo by Sebastian Pena Lambarri from Unsplash)

    Unique beauties

    Whale sharks may be known for their size, but that’s not the only special thing about their anatomy and appearance. Each whale shark sports a beautiful pattern of white markings on its dark gray back. Not only does this make these creatures look like giant mobile modern art pieces, but the patterns also uniquely identify whale shark individuals.

    It is not conclusively determined why whale sharks carry these unique signatures, their own version of the human fingerprint. Some scientists speculate that the patterns, which tend to be common among carpet sharks and other species that find such markings useful for camouflage as they traverse the ocean floor, indicate a close evolutionary link among these organisms.  

    The World Wildlife Fund has used these markings to identify individuals in the waters around the Philippines and keep track of whale shark population numbers there, so that humans can make the interventions needed to mindfully coexist with our marine friends. Whatever its distant origin or function today, this feature makes it clear that each whale shark is a special and irreplaceable member of our blue planet. 

    For gentle giants and filtering friends,
    Maya

    Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

    Sources and Further Reading:
    https://www.worldwildlife.org/species/whale-shark
    https://www.georgiaaquarium.org/animal/whale-shark/
    https://www.nationalgeographic.com/animals/fish/facts/whale-shark
    https://en.wikipedia.org/wiki/Whale_shark
    https://earth.org/endangered-species/whale-sharks/
    https://www.4ocean.com/pages/whale-shark-cause-of-the-month

    Featured Creature: Clamworm

    Photo by Alexander Semenov

    What sort of worm is festooned with sensitive tentacles all the way down its sides and – though it can’t bark – has a nasty bite?


    That would be the “clam worm” or alitta succinea, a denizen of estuarial waters.

    Photo by Alexander Semenov

    Alternative names

    I’ve always called them “seaworms” but they are normally known as “clam worms,” “ragworms,” “sand worms” or “pile worms”, and they are a species of annelid, the phylum of segmented worms.

    Size and habitat

    The clam worm can reach up to 15 cm (almost 6 inches) but most are smaller. This worm is reddish-brown in color, and has four eyes, tentacles or flaps all the way down its sides which can also function as gills, and sensory feelers at its head. 

    When hungry, it uses a long internal mouthpart called a proboscis, along with two hooks that unfold to capture and then draw prey into a mouth at its front end. These worms are themselves an important food source for fish and crustaceans, and are widely used as fishing bait. Their typical habitat is rocks, vegetation, reefs, and mud. They burrow into the mud or sand, or hide under rocks, to be safe from many potential predators.

    Photo from wikimedia.org

    My own first encounter 

    In my early teens, my father and I used to fish for striped bass with a flashy lure with a seaworm strung on a hook behind it. “Here’s how you do it,” my father counseled me. “Just poke the worm in its mouth and, as soon as it opens, insert the hook point.”

    “Owww!!!” I exclaimed. “This worm bit me!” My father laughed, almost as hard as during one of my earlier ‘learning moments’ in a Maine field, when halfway over an electric fence I got shocked! On neither occasion did I expect the bite, but I eventually learned to be more careful. Those pincers were sharp! 

    The pincers’ zinc content makes them strong while keeping them very lightweight. They certainly drew my blood that first time! The fish surely liked these worms, but eventually I gave them up for flies (less messy and easier on the worms).

    Spawning behavior 

    During the full and new moon tides in the late spring and early summer, these clam worms undergo a process called epigamy, which enlarges their parapodia (tentacles) so they can swim more easily to the surface to release their eggs and sperm, at which point their bodies rupture and disintegrate. Talk about dying to reproduce! One hopes at least they have fun on their way out. Their fertilized eggs then settle to the bottom and hatch into a new generation.

    Replacement parts 

    These worms can replace various body parts, and make new worms from broken pieces, such as when their tails are pulled off by a predator. But rear body segments are more readily repaired than heads, which are much harder to replace – those of us our heads still on can probably relate!

    Check out a short video on clam worms and their special properties:

    Their role in marine ecosystems 

    The tunneling and boring of marine worms irrigate and oxygenate the shallow water pools encouraging beneficial plant and algae growth. Whether it’s in tide pools, lowland waters or oceanic reefs, the marine worm’s primary ecological contribution is as sustenance for aquatic animals further up the food chain. Species of these worms respond quickly to increased amounts of pollution in the water and on the ocean bottom. Their presence or absence may indicate important changes in the marine environment.

    Some subspecies are at risk, but clam worms are OK 

    Most of this species is doing just fine, at least when not being used for bait or eaten by humans. However, you might just want to think twice before skinny dipping on May-June new or full moon tides!

    By Fred Jennings

    Featured Creature: Giant Barrel Sponge

    What creature grows tall and sturdy, cleans up its neighborhood, and defends itself from predators – all without moving a muscle?

    The Giant Barrel Sponge, or Xestospongia muta!

    Photo By Twilight Zone Expedition Team 2007, NOAA-OE – NOAA Photo Library (Public Domain, via Wikimedia Commons)

    A Giant Barrel by any other name… 

    Giant barrel sponges are aptly named for their shape and great size. They grow over 1 m tall, but only grow an average of about 1.5 cm a year. After all, good things take time! 

    Giant barrel sponges come in a range of colors, depending on the presence of the cyanobacteria that they work with in symbiosis. They can be pink, purple, brown, reddish brown, and gray, and tend to be different colors at different depths. 

    You may be wondering why this “giant barrel” doesn’t look very much like Spongebob Squarepants, or the sponge you use to clean up in the kitchen. Well sponges, or animals of the phylum Porifera, come in all shapes and sizes, and there is great diversity among the 8,550 species of them. Sponges are quite ancient, with their oldest fossil records dating back 600 million years, so they’ve had time to differentiate and find their own ecological niches.

    The giant barrel sponge is known as the “Redwood of the Sea.” The phrase comes from the fact that giant barrel sponges share the tendency for individuals to live long lives, from a few hundred to thousands of years old. In fact, the oldest known giant barrel sponge is over 2000 years old. 

    Old age isn’t the only thing they have in common with their counterparts on land. Like the magnificent redwoods, they do wonders to clean up and support the environment around them. Giant barrel sponges can filter up to 50,000 times their own volume in water in a single day. They also provide habitat to several small fish and other invertebrates that can be found living inside or on the surface of the sponge.

    Photo by Andre Oortgijs (CC BY-SA 3.0 via Wikimedia Commons)

    How does such a giant creature sustain itself?

    Although giant barrel sponges are, well, giant, their diet is anything but. These creatures, like many species of whales, sustain their size not by eating very large sources of food, but by eating large volumes of it. Giant barrel sponges are filter feeders, and consume microorganisms from the water around them that they pump through their bodies. The sponges have special cells along their inner cavities called choanocytes, which work to facilitate the movement of water and the capture of food from it.

    In their ocean food chain, giant barrel sponges take their place above their symbiotic partners cyanobacteria, and are consumed in turn by macroorganisms like fishes, turtles, and sea urchin. They try to defend themselves by releasing chemicals to repel their predators, but there’s only so much they can do when stuck in one place, waiting to be ingested by so many types of marine life. Like other filter feeders, giant barrel sponges ultimately form an important branch in the transfer of nutrients from very small to much larger life forms.  

    They don’t even have tissues, let alone organs, but their simple structure is more than enough to ensure their survival and proliferation. Giant barrel sponges reproduce by spawning, and are one of the few species of sponge that undertake sexual reproduction. Males and females release sperm and egg cells into the ocean synchronously, so that when the time comes, they have a chance of contributing to a fertilized egg that grows into a larva and, after being carried by currents to a new spot of the ocean floor, establishes itself as an independent sponge. 

    Check out this short video of the spawning phenomenon:

    A valued community member

    Giant barrel sponges are native to the oceans of the Americas, found primarily in the Caribbean Sea, and observed as far south as the coasts of Venezuela. 

    Due to their filtration capabilities, giant barrel sponges are real assets to the ecosystems they are a part of, but boosting water quality is not the only ecological role they play. As mentioned, many other creatures live in and around the cavernous sponges, and giant barrel sponges are one of the largest organisms in the coral reef environments where they are found. They are thought to help coral anchor to substrate (the mix of mineral, rock, and skeleton that binds reefs together), and themselves make up about 9% of coral reef substrate in certain areas where they are found. By helping in this binding process, giant barrel sponges can play an important role in reef regeneration. 

    Though the giant barrel sponge is not currently classified as threatened, like all of us, it is living in vulnerable times, as reef habitats are weakened in warming, acidifying waters. It is susceptible to a disease called Sponge Orange Band disease that afflicts all kinds of sponges. They can also be damaged or killed by human activities that disturb reefs and break sponges off from their surroundings. 

    On the flip side, when these great creatures are doing well, they enable the thriving of life all around them. May all of us aspire to say the same.

    With one giant smile,
    Maya

    Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

    Sources and Further Reading:
    https://animaldiversity.org/accounts/Xestospongia_muta
    https://oceana.org/marine-life/corals-and-other-invertebrates/giant-barrel-sponge
    https://en.wikipedia.org/wiki/Giant_barrel_sponge
    https://www.americanoceans.org/species/giant-barrel-sponge
    https://oceanservice.noaa.gov/facts/sponge.html

    Featured Creature: Pacific Salmon

    This week we ask,

    What creatures navigate oceans, climb mountains, feed forests, and motivate us to destroy renewable energy infrastructure?

    The Pacific Salmon!

    USEPA Environmental Protection Agency (Public Domain via Wikimedia Commons)

    How do salmon find their way home?

    Pacific salmon are famous for their migrations from the saltwater habitats they live in as mature adults to the freshwater rivers and streams where they were born and return to spawn. Salmon have two means of finding their way back to where they first hatched, often to the very same patch of gravel.

    In the open ocean, they have a GPS system based on the earth’s magnetic fields sensed through their lateral line (a highly-sensitive line of nerves running down each side of their bodies). When they get near shore, they then follow smells that they imprinted from their natal river up to where they originally hatched, to spawn again and continue this cycle.

    How do salmon manage to get back upstream?

    Salmon make their way back home against the current of streams and rivers, even climbing mountains in the process. As they go, they feed upland forests by transporting ocean nutrients into the headwaters of their natal streams, supporting all kinds of life in the process (and not just hungry bears)!

    Istvan Banyai (CC BY-SA 3.0 via Wikimedia Commons)

    What happens to Pacific salmon after they successfully spawn?

    Spawned-out Pacific salmon all die after completing their journey. In late fall, on a salmon river, rotting corpses and dying fish appear everywhere, white with mold and stinking with decay. In doing so, they feed forests and the aquatic life that sustains the next generation of fish when they hatch in the spring. We don’t really know why they all die after spawning, unlike the Atlantic salmon, which live after the process is complete. 

    Bears also increase the ecological reach of these salmon by catching them in rivers and streams and carrying them deep into the forest to feast. This brings their helpful nutrients, particularly nitrogen, into dense stretches of forest where they can fertilize the ecosystem and help trees grow. In fact, it is estimated that eighty percent of the nitrogen in the trees of the Great Bear Forest in Canada comes from salmon. Learn about the interdependent links of salmon, bears, and forest health here.

    Where do we find Pacific salmon?

    Pacific salmon are an anadromous species, which means they live in seawater but spawn in freshwater. They hatch from eggs in gravel and spend their early years in freshwater rivers up high in the mountains and forests along the Pacific coast. Then, once they reach about 6-8 inches in length, they move down through the estuarial waters to spend several years in the open ocean, feeding and growing large, before they journey upstream to spawn and die.

    What is the cultural significance of these fish?

    Pacific salmon are part of a religious cycle of life for Indigenous peoples on the American and Canadian West coasts as well as across the planet. Their annual return is celebrated as part of a natural process in which Autumn brings a bountiful harvest of fish to add to other stores of food to last through a long cold winter. Salmon are objects of worship by coastal native inhabitants, human and nonhuman alike, who depend on the annual return of these salmon in the fall to help them get through a long cold winter.

    A Shoshone-Paiute tribal member during the reintroduction of the Chinook Salmon
    into the East Fork Owyhee River by the Shosone-Paiute Tribe (May 28, 2015)
    (Photo by Jeff Allen, Northwest Power and Conservation Council)

    We want renewable energy sources! So why are we destroying them for these salmon?

    From the 18th into the 20th centuries, our human thirst for factory power had us constructing many dams on our rivers, with little attention to their harmful ecological impact. Many of our anadromous fish species – adapted to the specific conditions of their river watersheds – were lost forever when dams left them unable to complete their journeys upstream.

    It is only in recent decades that a powerful movement for dam removal and habitat restoration has been gaining momentum as a means of saving these precious species. The beneficial effects of removing these barriers have been spectacular, as rivers – freed from their shackles – blossom with new life. Along with the salmon have come a revival of other runs, including steelhead, herring, eels, shad and other diadromous fish (ones that transition between freshwater and saltwater environments), as well as birds and wildlife previously not seen in these areas. Our rivers are showing us all that we had lost and all the flourishing that is possible once we get out of their way.

    How are human activities impacting these salmon?

    Pacific salmon are in serious trouble. A thirst for hydropower has placed them at dire risk of extinction. We are removing dams, building fish ladders on existing dams (since their proper design is crucial), making sure culverts and other means of fish passage stay open and unhindered. But salmon are cold water species, so a warming planet puts them in peril.

    However, there is much we can do to protect them, and restore them once they are threatened or lost. Several short but informative videos on salmon restoration efforts can be found here and here.

    May we keep supporting the Pacific Salmon,

    Fred

    Fred is from Ipswich, MA, where he has spent most of his life. He is an ecological economist with a B.A. from Harvard and a Ph.D. from Stanford, both in economics. Fred is also an avid conservationist and fly fisherman. He enjoys the outdoors, and has written about natural processes and about economic theory. He has 40 years of teaching and research experience, first in academics and then in economic litigation. He also enjoys his seasonal practice as a saltwater fly fishing guide in Ipswich, MA. Fred joined Biodiversity for a Livable Climate in 2016.