Barnacles

Barnacles. Not a very sexy topic, I think we can all agree. They are just like carbuncles (almost a pseudo-anagram) on the surface of any object that spends long enough under seawater: boats, breakwaters, rocks, wrecks, even submarines, turtles and whales.

By the way, in a quick digression, scientists have just discovered an enormous 'whale graveyard' in the Diamantina fracture, four miles down at the bottom of the Indian Ocean. The graveyard is about  745 miles long and contains fossilised whale skeletal remains dating as far back as 5 million years ago, including several now-extinct species, as well as recent and currently decomposing bodies. Amazing or what?

Back to barnacles. Not very sexy, as I was saying, but tenacious little beggars. They've been around some 300 million years - i.e. way before there were boats or breakwaters to stick onto, so it must have been rocks, turtles and the occasional whale in those far off millennia. They are crustacea and there are are some 2,000 different species of them. They are exclusively marine invertebrates, less fanciful cousins of the crab and the lobster and nothing like limpets, which are molluscs.

Barnacles live mainly in shallow and tidal waters and are sessile (my word of the week) meaning they have no natural mobility, excepting during the larval stage, when they are busily floating around looking for a suitable surface to adhere to. Once they've found their spot, they secrete a water-resistant glue from glands in their heads, stick themselves head-first to their chosen substrate, and that's it, cemented in place for life, often upside down. Many species are hermaphroditic, and it only takes one to start a colony!

Mariners hate them, because barnacle colonies can form weighty encrustations on the hulls of boats, giving rise to what's called hydrodynamic drag, increased weight and reduced sailing efficiency. The only remedy is to scrape them off in dry dock, a laborious process.

a boat's bottom weighed down by barnacles

By the way, too many of them encrusting the shell of a sea turtle can make life difficult for the turtle as well, the extra weight, the increased drag, so animal conservationists often intervene to de-barnacle badly affected creatures by scraping the blighters off.

The most common barnacles have their own hard outer carapace or shell, made up of six calcareous plates which protect the organism inside. They open up to feed, waving their feathery legs around as in the diagram below to entrap floating plankton and pull their prey down into their shells. They are heartless creatures, literally it appears. They have stomachs, guts, an anus but no heart that anyone has been able to find, and no brain to speak of. They are just eating, shitting and reproducing automatons, serving no useful purpose as far as I can see.

a barnacle opening up to feed

And yes, reproduction. I've said barnacles are not very sexy. However, because they can't move around once glued in place, if they want to mate they have to be able to penetrate the nearest barnacle, which may be quite some distance away. As a result, barnacles have the largest (i.e. longest) penis in relation to body size of any animal. If you take nothing else away from this blog, take that surprising fact. It may come in useful one quiz night. 

I don't have anything more of interest to say on the subject.

an anchor's flukes encrusted with barnacles

Usually I find myself posting these blogs quite late on a Saturday, sometimes only just before midnight, but I've set myself a deadline of 10:30pm because I plan to watch Morocco in their opening world cup fixture against Brazil and that kicks off at 11:00 pm. 

I haven't written an acrostic poem in a while, so thought I'd give it a try this evening.

Barnacles

Briny little beggars,  sessile too.  Moored  headfast for life, stuck to their spot,
A seaside breakwater, a rock, or if  they're lucky a ship's hull, perhaps a whale,
Rare opportunity to get around, see a bit of the world, except they've no eyes.
No heart either, for that matter, briny little beggars from Carboniferous times,
Aquatic automata  made to eat, shit, reproduce without advance for millennia.
Clam up  at low tide, though they're not clams  but simple, stubborn crustacea
Look a bit volcanic, then opening up like Tracy Island,  waving those tentacles 
Enticingly to fill their stomachs with passing  plankton and tiny marine debris.
Surprising fact: their penis in ratio to body size, largest in the animal kingdom. 

Thanks for reading, S ;-)

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Barnacles

What with celebrating some significant birthdays (including mine) and the opening of a new bridge then time has been a bit of a problem this week. Especially when it came to examining the topic of Barnacles. I know nothing about barnacles except that they stick to the bottom of boats and the skin of whales.

barnacles

With that in mind I’m making no apologies (well, a small one) for taking the following information virtually direct from a web site called AskNature. It states that:

‘We exist to encourage everyone, everywhere to have a direct experience with nature that is founded on respect and curiosity. We have designed this tool to provide guidance to students, educators, engineers, scientists, designers, artists, naturalists, and those from yet to be defined disciplines. Our hope is that this is a homecoming for anyone on a journey to make the future better for all of our planetary neighbours. This page was produced in part with the assistance of AI, which is allowing us to greatly expand the volume of content available on AskNature. All of the content has been reviewed for accuracy and appropriateness by human editors. To provide feedback or to get involved with the project, contact us. Last Updated January 30, 2025’

Introduction:
Barnacle larvae, the juvenile stage of these familiar marine crustaceans, exhibit a remarkable ability to permanently adhere to underwater surfaces. Found in oceans worldwide, barnacles attach to rocks, ship hulls, and other structures, often forming dense colonies. Their adhesive is one of nature’s most durable underwater glues, capable of withstanding harsh conditions like strong currents and waves. The mechanism behind this adhesion lies in a sophisticated interplay between lipids (fat-like molecules) and proteins, creating a permanent bond that is strong and versatile.

The Strategy:
Barnacle larvae use their adhesive to secure themselves to surfaces when they settle into a permanent home. This process begins with the secretion of a complex mixture of biological materials including proteins, which form the structural framework of the glue, and lipids, which play a supportive but equally essential role.

barnacle adhesion

The proteins in the adhesive are responsible for forming strong bonds with the surface and with each other. These molecules have unique properties that allow them to stick even in wet environments, where water typically weakens adhesives. The lipids serve to create a waterproof barrier on the surface, helping the proteins adhere by repelling water and ensuring that the glue remains intact over time. Together, these components work synergistically to produce a bond that is both strong and highly resistant to environmental wear.

The barnacles’ strategy is especially effective because the adhesive is self-organizing. As the larvae secrete the adhesive, the lipids and proteins automatically arrange themselves into layers, with lipids coating the surface first, followed by proteins that solidify the bond. This layered structure maximizes durability and adhesion while maintaining flexibility to adapt to different surface textures.

The Potential:
The barnacle larvae’s adhesive offers inspiration for developing advanced, environmentally friendly glues that work in wet conditions or underwater. Such adhesives could revolutionize industries like construction, medicine, and marine technology. For example, medical adhesives inspired by this strategy have been used to expedite wound healing, providing strong, biocompatible bonds under varied conditions.

Well, I found that really interesting. The above is about the future so for the poem I’ll go to the past with this poem by Sidney Lanier.

Barnacles

My soul is sailing through the sea,
But the Past is heavy and hindereth me.
The Past hath crusted cumbrous shells
That hold the flesh of cold sea-mells
About my soul.
The huge waves wash, the high waves roll,
Each barnacle clingeth and worketh dole
And hindereth me from sailing!

Old Past let go, and drop i' the sea
Till fathomless waters cover thee!
For I am living but thou art dead;
Thou drawest back, I strive ahead
The Day to find.
Thy shells unbind! Night comes behind,
I needs must hurry with the wind
And trim me best for sailing.

                                    Sidney Lanier, 1867

Thanks for reading, Terry Q.

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