Finding a barnacle inhibitor that will have any remote chance of being commercial must meet a major hurdle – the cost.

Having been a fish developmental biologist in my younger days and a biomedical scientist in my middle years, my own passion for barnacle research did not come until later, after meeting Prof. Dan Rittschof at Duke University Marine Laboratory and Sister Avelin Mary at Sacred Heart Marine Research Centre (SHMRC) in the early 1990s. Barnacles are not exactly the cute furry creatures one can get passionate about, so I have to admit that the interest was partially clouded by my capitalistic pursuits. That was the time when the ban on tributyl tin (TBT) was just looming on the horizon and there was a mad pursuit to discover the ultimate nontoxic barnacle settlement inhibitor. The search for TBT-free antifouling was the ‘holy grail’ of the marine paint business.

Before discussing my version of business evolution at Poseidon Ocean Sciences, I wish to digress a little to talk about Darwin and the barnacle. Like many of us in this business, we write about the barnacle, Balanus amphitrite amphitrite Darwin, and yet do not give any thought to why Darwin’s name came to be part of this nomenclature. So, let me tell you why.

Charles Darwin

The Charles Darwin we are all familiar with is the English naturalist who wrote On the Origin of Species by Means of Natural Selection in 1859, which has since become the foundation for our understanding of evolution and the unifying explanation for the diversity of life on earth. He wrote about his theory in 1844, then quickly shelved it inside his desk drawer, specifically instructing his wife to release it for publication only if he died unexpectedly. Darwin was a modest man who shied away from controversies, and he knew his theory would be controversial; it remains so even on this year’s 150th anniversary of writing On the Origin of Species.

For 20 years, this document remained hidden until he received a letter from a young English naturalist, Alfred Russell Wallace, then living in an island of what is now Indonesia. In a malarial fit, Wallace remembered reading Thomas Malthus’ 1798 Essay on the Principle of Population (which coincidentally also inspired Darwin) and reached his own Eureka moment totally independently. He quickly dispatched a letter to Darwin describing an almost identical theory of evolution. In the typical Darwin sense of fair play, he presented Wallace’s ideas and his own at the same time during the meeting of the prestigious Linnean Society, giving equal credit to the idea of Wallace and the share of the controversy as well. Yet, Darwin is credited with the theory of natural selection because his ideas were written while Wallace was yet in his teens, over 20 years before.

Then, you may ask, what did he do for those 20 years? Besides dealing with his failing health and the tragedies in his life, he was consumed by the passion of cataloguing barnacles. His interest in these tiny, ugly creatures began during his famous around-the-world voyage in HMS Beagle. Then, at the age of 26, young Darwin was exploring the Chilean coastline looking for biological specimens when he came upon a conch shell with its thick shell riddled with tiny boreholes. Inside the hole was a microscopic creature, attached by its head to the shell and waving six tiny legs. Knowing that it was a barnacle without a shell, Darwin became even more fascinated since it had never before been described by any naturalist. He was a disciplined taxonomist and organized the chaotic nomenclature of this organism that number over 1000 species. Most of the species were often misnamed during his lifetime. Upon his return to England and immediately after writing his ideas on natural selection, at great expense to his health, he began his day and night obsession with barnacles that lasted for eight years (1846-1854), cataloguing the collection from his voyage and from the hundreds more sent to him by mail from around the world.

What drove this passion about such a mundane organism? Perhaps a clue comes from an earlier anonymous publication in 1844 of a controversial, incendiary, speculative book, Vestiges of the Natural History of Creation (later confirmed to be the work of Robert Chambers, a Scottish medical journalist). Widely panned and mocked for its evolutionary ideas even by Darwin’s friends, the failure of the book was a great personal disappointment because Darwin expected a similar response to his own ideas in On the Origin of Species. Even his best friend, the noted botanist Joseph Hooker wrote, “no one has the right to examine the origin of species who has not minutely described many.” Perhaps, one reason for this obsession was indeed to minutely observe a distinct part of the natural world and in so doing earn his right to question their origins. Whatever the reason might be, Darwin started us all on a path of research towards understanding barnacle biology and the commercial opportunities that follow in its wake.

Development of Poseidon Ocean Coatings Research

Though not as dramatic as Darwin’s, my adventure towards discovering the ultimate barnacle settlement inhibitors followed similar paths as many of us. The 1990s was a time when marine biotechnology was in its heyday and a lot a promise for a ‘cure all’ was just beyond the horizon. Scientists were extracting every marine organism they could get a hold of and looking for bioactive chemicals. For us in the marine paint industry, the goals were purely mercenary – finding one chemical, that ‘magic bullet’ that would bring great income opportunity especially for fledgling companies like mine.

At the time, the main workhorse in barnacle research utilized the method developed by Dan Rittschof called the barnacle cyprid assay, which still remains the best method to date. Here, the larvae are artificially cultured until they reach the stage called cyprid when they are competent to attach to surfaces. The cyprid assay still remains the best screening method to date. But, it was labor intensive and needed a green thumb to culture the barnacle larvae (and all the microalgae needed as food to sustain them artificially). Considering the sheer number of chemicals I wanted to test and the limited time available, Dan Rittschof suggested I collaborate with Sister Avelin Mary, who was his post-doctoral student and had since returned to India to establish her own laboratory. Sister Avelin got her Ph.D. in biology to become one of India’s most celebrated marine scientists. Because the internet had not yet reached her place in the port city of Tuticorin in the mid-1990s, collaboration depended solely on snail mail and fax (both unreliable even at the best of times) between New York and Tuticorin. I often wonder at how patient we were in those days. Yet, we were able to identify an active fragment from the purified extract called juncelin, named after Sister Avelin and the soft coral, Juncela. Through computer simulations of the structure of the fragment, we were able to identify the molecular structures that likely would repel barnacles, not kill them.

Barnacle Inhibition Development

Finding a barnacle inhibitor that will have any remote chance of being commercial must meet a major hurdle – the cost. Marine paint biocides are an industrial commodity, huge volumes at low cost; a commodity that should cost no more than US $100 per kilogram. Knowing what the structure should look like, we began cross-matching known compounds that are relatively cheap and used either as food ingredients or in pharmaceuticals for human and veterinary use. This was Poseidon’s Natural Bioproducts Screening Programme. Our presumption was that we would likely find from such a known inventory a series of compounds, we referred to as the NB series, with similar structures that were reasonably safe and could be mass produced cheaply. Years later, we narrowed our search of NB compounds to small molecules with menthol-like configurations, finally settling on a menthol derivative called menthol propyleneglycol carbonate, a GRAS (generally recognized as safe) food ingredient used as cooling agent in chewing gum and cosmetics (Figure 1). This chemical, based on tests, had repellent characteristics not only against barnacles, but also flies, mosquitoes, termites and even head lice. I suppose barnacles are nothing more than simply bugs in the sea! No wonder agro-chemical companies are taking their crop protection chemicals and testing them out against barnacles too. We just did it the hard way, starting from the ocean. Millions of dollars of R&D money and a decade later, I was hoping for a more exotic looking chemical besides a menthol derivative.

Field Testing