THE Royal College of Surgeons in Ireland hosted its annual outreach lecture last week.
The speaker was the Cambridge microbiologist Brian Ford, whose theme was the extraordinary stratagems of bacteria and single-celled animals in their battle for survival.
Professor Ford has an axe to grind.
He says journalists and broadcasters ignore the world of the minute. Animal media stars are mammals, birds or reptiles.
Fish get a share of the limelight and insects and spiders have 15 minutes of fame, occasionally. The tiny creatures on which everything else depends never get a look in. Even when microbiology features in science documentaries, computer graphics are used rather than actual footage.
Since attending the lecture, I’ve been watching for micro-creatures to write about on the Outdoors page. Professor Ford is right; there are fascinating stories available and one of them is appropriate now. On March 31, 1909, the hull of the Titanic was launched in Belfast. It was the largest moving object on the earth. April 15, 2012 is the 100th anniversary of the ship’s tragic end. But its story is not over. The wreck was located, and explored, using a robotic under-water device in September, 1985. The site, it was hoped, would become a memorial, but, alas, it won’t.
Brown, icicle-like structures are growing on the rusty metal.
The spikes are porous, so that water flows in and out of them. At least 27 micro-organisms reside in these ‘stalactites’.
Among them, a strange species of bacterium has been discovered. It has been named Halomonas titanica, after the ship.
This tiny organism has a strange diet; it eats iron. The huge sheets of rusting metal have become covered with the little conical structures, and the bacteria inside them are slowly reducing the wreck to knob-like mounds of powder.
Henrietta Mann, of Dalhousie University, in Nova Scotia, a co-author of scientific papers on the mysterious organism, says all traces of the iconic ship may be gone 30 years from now.
That a bacterium can attack steel plates seems extraordinary. Iron may be the fourth commonest element in the Earth’s crust, but it’s not found in its metallic form anywhere.
Apart from rare meteorite fragments, some of which are composed of iron-nickel alloys, this metal only occurs, combined with other elements, as iron ore. It’s such an elusive substance that it took us millennia even to discover its existence.
Fragments of meteorites are easy to find on bare expanses of desert, so it’s not surprising that, 5,000 years ago, the ancient Egyptians were the first people to use iron.
The so-called Iron Age did not begin until 3,300 years ago, when ore was quarried and smelted for the first time in what is now eastern Turkey.
But humans are not the only creatures to exploit iron.
The oldest organisms on Earth are bacteria that flourish in the absence of oxygen. In the intense heat, deep underground, some of them began altering the chemical combinations of iron salts, releasing energy they needed for themselves in the process.
The earliest life-forms, it was thought until recently, used sulphur to get going but, in 1998, Derek Lovley, of the University of Massachusetts, argued that the crucial element was iron. He cited geological research which showed that sulphur, in a form to support life, was not present on the early Earth. Magnetite, an oxide of iron, was abundant. Following a series of experiments using species of modern bacteria that live in high-temperature environments, he argued that iron was the crucial element back then.
If he’s right, iron-eating bacteria could be the ancestors of the creatures, including ourselves, roaming the Earth today.
But how did such a bacterium get to the wreck of the Titanic, 3.5km below the surface of the sea and hundreds of kilometres from land? It could hardly have evolved from another bacterium in such a short time, so it was a passenger on the ship when it sailed.
If so, Halomonas is the ultimate Titanic survivor.
a d v e r t i s e m e n t
This appeared in the printed version of the Irish Examiner Monday, June 20, 2011
