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Macrotritopus is a familiar-looking creature in the crazy world of plankton
 

Black-water diving has become the latest craze in macro photography. Whether it is hanging from an open line in the middle of deep water, or doing a “bonfire” dive close to shore, the idea is the same. At night, the billions of tiny creatures that we call plankton come up out of the twilight zone to feed on even smaller creatures in shallow water. These creatures are some of the most bizarre and alien animals that you can find on Earth, so no wonder photographers are flocking to find them.

The trick to photographing any animal in its natural environment is to understand its behavior and how they live. If you know this, you stand a better chance of knowing what you see in the darkness. If you know what you are shooting, then you increase your odds of getting that fantastic “money shot.”

We keep hearing about plankton in the ocean, and we always describe their population as “countless.” But have you ever really looked at them closely? Have you wondered why they look the way they do? Some of them might even appear surprisingly familiar: Take a look below and see if some of them might look like bigger creatures you’ve seen on day dives.
 

Larval lionfish, a giant in the planktonic world
 

Larval wunderpus, probably the creature that really ignited the current black-water craze

What Exactly Is Plankton?

Some of the animals in the images above are probably not new to you, but yes, they are all plankton. “Plankton” is a collective term that refers to all drifters in the ocean. They could be in deep water or shallow coastal areas, but all of them live and drift aimlessly in the water column. In fact, the name “plankton” aptly comes from the Greek word planktos, which means “drifter” or “wanderer.”

The volume of these creatures in the water is unbelievable. Check out the video below for an excellent example of what we are talking about. To shoot this, we set up two video lights about 3cm (an inch and a bit) apart and pointed them at each other. We then set a camera—a Panasonic Lumix GH5 with an Olympus 60mm macro lens and Nauticam SMC wet lens—to shoot super slow-motion, manually focused on an area of less than two square centimeters (about one-third of a square inch). We’ve called this black-water “blowtorch” diving.

These creatures have always been there, but for a long time divers and photographers took little interest in them. For years, we swam right by them in our incursions underwater because we naturally tend to look for critters on the seafloor. All the while, they have been floating around us and above us in midwater.
 

A random sample of what we filmed: We ended up shooting nine hours of slow-motion on a single dive!
 

There has been growing interest in photographically documenting plankton not only because of their novelty but also because they look otherworldly. Take, for instance, larval fishes (albeit planktonic only until they grow into their swim-capable adult versions): These young critters are transparent-bodied to compensate for their poor swimming skills with invisibility. This developmental design has enabled them to wander unseen in the water column alongside unsuspecting predators.

Because of this characteristic, as is typical with other “meroplankton”—critters that go through a temporary planktonic phase only—larval fishes do not look anything like their adult versions. A common larval fish in the coastal areas that shows up on night dives is a larval flounder.
 

The larval flounder is even wilder looking than when it is fully grown!
 

The ethereal beauty of a sea butterfly

Physical Characteristics

A distinct physical manifestation giving many plankton—especially larval crustaceans—a unique appearance are bodily spikes. Presumably, these spikes deter predation in their hapless free-swimming state. The spikes on the soft-bodied zoea below, a crab in its early developmental stage, will eventually be shed and replaced with the hard protective carapace we see in common adult crabs.
 

Like an invader from Mars, the crab zoea
 

Color is another physical characteristic that gives plankton their out-of-this-world look. Ctenophores, for example, not only use their cilia to gently propel themselves around but also to generate a mesmerizing internal light show. They can somewhat resemble a UFO underwater and could inspire artistic representations of extraterrestrial spaceships! Ctenophores are sometimes referred to as “comb jellies,” too, because they have comb rows as evident when they put on their light show.
 

Ctenophore, or comb jelly, putting on a light show
 

Some plankton is just plain bizarre looking. Holoplankton, or those critters that remain planktonic throughout their life cycle, often take on shapes or appearances that we are just not used to seeing underwater—or on land for that matter. This pelagic gastropod mollusk shown below, a holoplankton, is totally unlike other mollusks we know. The only seeming similarity is that it bears a tiny shell typical of the mollusks we are familiar with. It has even been said that their small and fragile shells are highly sought after by conchologists, those who have an interest in collecting and studying shell specimens.
 

The pelagic gastropod mollusk could be something straight out of Star Wars

Planktonic Behavior

There are many more exciting peculiarities about the planktonic cosmos. Do not be fooled by their unusual and appealing beauty, and seemingly harmless demeanor: The tiny planktonic universe is a very violent world. A superficial look at their physical attributes, as we have just done, suggests that genetic evolution has been at work, with a focus on equipping them with specialized physical attributes for surviving a harsh world filled with predation.

Some people would surmise that plankton exists to be eaten—food for fellow plankton, fish, and also massive filter feeders like whale sharks and manta rays. This would only be true if we view plankton from our gigantic sized world. In their tiny cosmos, some of them are the giants. In the microscopic world of plankton, there’s always something smaller to feed on, like the little juvenile squid, below, feeding on an even tinier shrimp.
 

There’s always a bigger (or smaller) fish: A juvenile squid eating a larval mantis shrimp
 

The fact that plankton form the basis of the entire oceanic food chain is why their numbers are so vast. Whether they are fully grown, or an animal still in a juvenile stage, the plankton of the world represents a stunningly large percentage of the world’s biomass. Their world may be small, but it is no less fascinating to observe. Indeed, the unconventional combination of intense beauty and violence in the world of plankton only makes you want to learn more about them.
 

Melibe: You can even find nudibranchs in the planktonic swarm
 

About Ram Yoro: Ram is a recreational scuba instructor, tech diver and underwater photographer based in the macro capital of the Philippines, Anilao. Aside from being a pioneer in the bonfire method for photographing plankton, he is also active in exploring caves, wrecks, and reefs in the region. Some of his recent works are published in “Let’s Go Dive: Guide to Anilao” and “Legends Beneath the Waves: Philippines,” where he is co-author with Andrew Marriott. He is also one of the contributors in the book “Black Is the New Blue, Volume 2,” which features the works of avid black-water and bonfire photographers. When not in exploration or shooting mode, Ram regularly conducts underwater photography workshops and partakes in judging photo competitions. Outside his Facebook and Instagram pages, he regularly shares his works through the dive expos in the region.