One reason why I’m so drawn to the ocean is that it’s never boring. Every hike along the coast, every day sailing the sea and every plunge beneath the waves is full of surprises.
The ocean is peaceful: so calm that the vessel you’re aboard may as well be slicing through glass, as you gaze towards the horizon that in this moment doesn’t exist, for in this moment the sea and sky are one.
The ocean is angry: its turbulent waves dwarfing even the grandest of ships, breaking spirits, taking lives and destroying cities.
The ocean is generous, feeding millions of people daily; the ocean is cruel, merciless for countless adventurers at the limit of their abilities. The ocean is a metropolis, teeming with an unfathomable diversity of life; the ocean is a desert, immense and empty for miles on end.
The ocean is full of contradictions, as are its inhabitants.
When we first arrived in Punta Galeta, Colón for our two-day excursion, I must admit that I was disappointed. We were staying at one of STRI’s renowned marine field stations on Panama’s gorgeous Caribbean coast, where waters are warm, waves are gentle and marine life is abundant. Part of what makes Panama’s coastline so unique and the perfect space to study marine ecosystems is the diversity of habitats that are observed in a relatively small area.
The immediate surroundings of the Galeta research station feature dense mangrove forests, blurring the border between land and sea, lush beds of seagrass, perfect for grazers such as manatees and sea turtles, and vibrant coral reefs, home to a dizzying plethora of brightly-patterned tropical species.
While the first two weeks of the course were undoubtedly exciting and inspiring—from waking up to howler monkey calls on Barro Colorado Island to breathtaking views atop the forest canopy from a research crane, to the warmth and hospitality of the indigenous groups of Lake Bayano—I couldn’t help but impatiently anticipate the amazing time we were going to have snorkelling in Galeta.
Unfortunately, we were met with unusually windy weather and turbulent, turbid waters. Heavy undercurrents made it dangerous to swim out onto the reefs, and underwater visibility was so poor that it was pointless to attempt to do so anyways.
Nevertheless, we still had a great time carrying out a predation experiment in and around the mangroves. And any disappointment I felt from being unable to identify said predators due to the murky conditions quickly evaporated, as a lone alien creature slowly and almost ominously drifted past while we were in the water.
At first glance, you might mistake them for a plastic bag or a discarded inflatable—we certainly saw a fair share of rubbish washing onto the shores. But then, there’s something off that you can’t quite place—you might be taken by how smoothly it cruises the waves, uncharacteristic for inanimate marine debris. And when you stop what you’re doing and squint your eyes to make sense of what you’re seeing, you’re struck by its brilliant magentas and blues, and the ethereal folding patterns of its crest above the waves—like a delicately glass-blown sculpture. As it dawns on you exactly what you’re witnessing, you forget about the experiment you’ve been setting up and just gaze in awe as it drifts by, wondering if it has any agency in deciding its path. You suddenly tense up when you remember its long tentacles trailing beneath the surface, unsure of whether you’re within range of their paralysing venom.
We saw four or five of these perplexing creatures during our brief stay, and they never failed to enchant me. Even its name, the Portuguese man-of-war, is intriguing, mysterious and a little unsettling.
The Portuguese man-of-war is the common name for Physalia physalis. They are not jellyfish but a species of siphonophore, which are organisms comprised of a colony of clones (called zooids) working as one. These zooids are unable to survive alone, which is why they’re physiologically integrated, each specializing to perform a specific function.
The part of a Portuguese man-of-war one usually sees is its translucent gas-filled bladder, or pneumatophore, which rests at the surface of the water. This bladder can be up to six inches tall and acts as a sail, letting the wind (as well as currents and tides) propel its course. The float is said to look like the sails of an 18th century Portuguese warship, hence its name. Portuguese man-of-war are said to live in groups of up to 1 000 or more, though we only saw lone individuals.
Beneath the surface lurk the man-of-war’s tentacles, which can be up to ten metres long. Covered in venomous needle-like nematocysts, they permanently drag through the water like abandoned fishing lines, stunning the likes of small fish, shrimp and copepods. The man-of-war’s potent cocktail of venoms includes compounds that lyse cells and break down proteins and fats, beginning digestion almost immediately. Their prey is then drawn up towards zooids specialised in later-stage digestion.
One fish species has taken advantage of the Portuguese man-o-war’s menacing anatomy: the man-of-war fish lives within the Portuguese man-of-war’s deadly tentacles, presumably as a form of protection from would-be predators and is even known to feed on the siphonophore itself. The fish has limited immunity to the siphonophore’s venom, and gambles using incredible flexibility and agility to avoid being stung by its tentacles.
Besides these basic facts, not too much more is known about Portuguese man-of-war’s life histories or ecology. They are usually found in the open ocean, are impossible to tag, and do not live long in captivity.
They are a perfect example of the self-contradicting nature of the ocean: capturing the intrigue of naturalists, artists and beachgoers alike, daring its observers to take a closer look—only to punish them should they overstep their bounds. As beautiful as they are deadly.