These are some of the biggest vessels humans have ever built!
Ironically, the lowly barnacle is a principal enemy of these sea-going behemoths…
This is a story of how a
Big Business crucial to the
Global Economy can be
brought low by a
Tiny but Stubborn
little creature!
Even though it is tiny, the barnacle is a formidable creature. It hangs on to hard surfaces using one of the strongest glues in the world, as it nets its food from the water. This seriously damages the efficiency of a ship; it causes drag,and drag can be both expensive and dangerous - both wasteful of fuel and making it impossible to steer.
Mariners call it “fouling”, and they have been fighting it for centuries.
At one time, ancient sailors chipped the intruders off the hull with hammers.
Modern shipping industry switched to toxic paint, which poisoned harbours and waterways more than the barnacles.
Now, the search is on for a new method, to keep both our ships and our oceans clean.
Segment 1 - Know Your Enemy!
(A “Blue-Chip” Natural History of the Barnacle)
Rocky shores round the oceans of the world are a hostile and difficult place to live, ...
but they are home to a huge and diverse community of plants and animals.
This is because they are deluged with food, millions of microscopic creatures that live in the constantly swirling water. If an animal can hang on, and has a filter or net system for gathering this free food, it can flourish.
The competition is intense – everyone who can make it wants to live here.
Barnacle larvae are hardly bigger than the food particles in the water.
They look like tiny shrimps, with jointed legs and antennae.
When the time comes to settle down, the larva glues its antennae to the rock, secretes a stony shell round itself, and spends the rest of its life standing on its head sweeping food particles into its mouth with its legs.
Its mating behaviour is very strange to our eyes, but perfectly normal to a barnacle...
With a penis several times longer than the rest of its body, the barnacle reaches out across the colony to mate with a neighbour several doors down the street!
There is no problem in choosing a partner, because all barnacles are female as well as male. The barnacle colony forms the basis of a community of other equally strange animals.
Competition for good feeding spaces on the wave-lashed rocks is intense, and critters in this community have to defend their tiny territories any way they can.
Mussels look rooted to their spots and helpless, but, as we shall see, are amazingly good at defending themselves.
When a predatory dog whelk, (a snail-like creature that feedsby drilling through the mussel’s shell) attempts an attack, a blue mussel can use its byssal threads – the same amazingly strong, rope-like fibres that hold him to the rocks -- to grab theattacking snail, yank it off its rock and leave it upside down ... to starve to death.
It is a competition as fierce as the lions and hyenas of the Serengeti,
except that it’s a slow-motion battle over a few inches of wet rocks knee-deep in cold water.
All this rich assembly of life is a source of wonder to us – but it is a cause of grief and anger amongst mariners…
Segment 2 – Battling Barnacles Through the Ages
Ever since humans first sailed the seas, they have battled the barnacle.
Roman galleys, and all wooden ships for centuries afterwards, had to be beached and careened, turned on their side to be scraped clean (from the Roman word for a keel, carina). If this wasn’t done, the ship could become unusable in a matter of years.
As we learned in Segment One, our seas are a rich soup of microscopic organisms.
Imagine putting an enormous new surface into this environment, by launching a huge ship.
Such is the pressure of life that within one minute the new surface will be settled by living organisms.
Only tiny bacteria, sure, but they are the start of a process that can end in a densely packed city of filtering animals.
We shall show in time-lapse photography just how quick and complete this encrusting process can be.
In the eighteenth century, a massive breakthrough was the invention of the copper bottom, a very expensive but effective way of preventing encrustation.
When biologists realised why this works – because copper is poisonous to marine life – new coatings were invented, anti-fouling paints using tin as well as copper to keep the hulls clean.
These coatings work by continuously releasing small amounts of poison into the water.
This keeps the slime and barnacles at bay, but the toxins sink to the bottom, poisoning harbours and other enclosed waterways such as ship canals.
Today, the sediments in most major ports are thick with metal toxins that have “rained” down on them for decades from anti-fouling paints.
This rain of poison has other strange, unexpected effects…
In one case, the toxins that have lain in the muck for decades can alter the sex hormones in the dog whelks that prey on mussels and barnacles.
The effect is that the male side of each whelk overwhelms the female side. With a shortage of functioning females, the whelks can no longer breed. This might be good news for mussels and barnacles - but very bad news for the rocky shore community, which needs there to be some ecological balance, if other creatures are to flourish.
Segment 3 – Big Technology vs. Little Critters
Despite decades of environmental warnings, toxic anti-fouling paints continue to rain poison on the sea bed.
Authorities at many major international ports are banning poison-based paints, while others are still locked in debates – fearful that strict environmental rules may dive business elsewhere.
Meanwhile, most Military craft are exempt from such regulations, and continue to leach poisons as they patrol the oceans of the world.
As government regulators continue to push the debate forward, some enlightened commercial ship operators have sought non-poisonous technological alternatives.
In their struggle to find environmental solutions that make economic sense, some commercial operators are looking to nature for a solution.
Like big ships, whales often suffer from barnacles …
… and yet whale sharks do not!
The shark’s secret lies in the design of their skin.
Seen under a electron microscope, the shark’s seemingly smooth skin is actually an intricate pattern of overlapping hard armour plates.
This tough, forbidding surface resists slime, and makes it impossible for barnacles to attach.
Through an approach called bio-mimicry, technologists are developing a number of products that imitate this microscopic strategy, and are applying it to some of the largest commercial vessels and cruise ships.
The age-old battle of the barnacles was once waged by the ancient Romans with primitive hammers and chisels …
… now continues with a vast arsenal of technological weapons; underwater power brooms, sophisticated, hi-tech coatings filled with micro-shards of tempered glass, and a host of other exotic new technologies being developed everyday.
The scale of an operation like this is huge, and requires special expertise, expensive, custom made equipment - and no small amount of danger.
The world’s biggest vessels are having to take some extraordinary steps to battle some of the world’s tiniest creatures.
How can these giants prevail without destroying the oceans?
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