The Swarm by Frank Schätzing Page A

we’re almost certainly dealing with the species Hesiocaeca methanicola , also known as the ice worm.’
    â€˜The methane-eater.’
    â€˜Wrong, but never mind. Anyway, that’s the first point. The second is that we’re baffled by its highly developed jaws and teeth, which usually indicate that the worm is a predator or that it gets its food by burrowing or grinding. Ice worms don’t need teeth like that, so their jaws are significantly smaller. They live symbiotically, grazing off the bacteria that live on gas hydrates…’
    â€˜Hydrates? asked Sverdrup.
    Johanson glanced at Lund. ‘You explain it,’ she said.
    â€˜It’s quite simple, really,’ said Johanson. ‘You’ve probably heard that the sea is full of methane.’
    â€˜So the papers keep telling us.’
    â€˜Well, methane is a gas. It’s stored in vast quantities beneath the ocean floor and in the continental slopes. Some of it freezes on the surface of the seabed - it combines with water to form ice. It only happens in conditions of high pressure and low temperature, so you have to go pretty deep before you find it. The ice is called methane hydrate. Does that make sense?’
    Sverdrup nodded.
    â€˜Hordes of bacteria inhabit the oceans, and some live off methane. They take it in and give out hydrogen sulphide. They’re microscopically small, but they congregate in such large numbers that they cover the seabed like a vast mat - a “bacterial mat”. They’re often found in places where there are big deposits of methane hydrate.’
    â€˜So far, so good,’ said Sverdrup. ‘I expect this is where the worm comes in.’
    â€˜Precisely. Certain species of worm live off the chemicals expelled by bacteria. In some cases, they swallow the bacteria and carry them around inside them; in others, the bacteria live on their outer casing. Either way, that’s how the worms get their food. And it explains why they’re attracted to gas hydrates. They make themselves comfortable, help themselves to the bacteria, and relax. They don’t have to burrow because they’re not eating the ice, just the bacteria on it. The only effect theyhave on the ice is through their movement, which melts it, leaving a shallow depression, and that’s where they stay.’
    â€˜I see,’ said Sverdrup, slowly. ‘So there’s no need for them to dig, whereas other worms have to?’
    â€˜Some species eat sediment, or substances present in it, and others eat any detritus that sinks to the seabed - corpses, particles, remains of any kind. Worms that don’t live symbiotically with bacteria have powerful jaws for catching prey or burrowing.’
    â€˜So ice worms don’t need jaws.’
    â€˜Well, they might need them for grinding tiny quantities of hydrate or filtering out bacteria - and, like I said, they’ve got jaws. But not like the ones on Tina’s worms.’
    Sverdrup seemed to be getting into the discussion. ‘But if Tina’s worms live symbiotically with bacteria…’
    â€˜We need to figure out why they have such killer teeth and jaws.’ Johanson nodded. ‘And that’s where it gets interesting. The taxonomists have found a second worm with that jaw structure. It’s called Nereis and it’s a predator found in ocean depths all over the world. Tina’s worms have Nereis’s teeth and jaws but in other respects they resemble its prehistoric forebears - a kind of Tyran-nereis rex .’
    â€˜Sounds ominous.’
    â€˜I’d say it sounds like a hybrid. We’ll have to wait for the results of the microscopy and the DNA analysis.’
    â€˜There’s no end of methane hydrate on the continental slope…,’ said Lund, playing with her lip ‘…so that would fit.’
    â€˜Let’s wait and see.’ Johanson cleared his throat. ‘What do you do, Kare? Are you in oil