The Swarm

'And does the sediment tell us what caused it?'

'Methane,' said Bohrmann. 'The sea temperature seems to have risen, causing large quantities of hydrates to become unstable. The continental slopes collapsed, resulting in underwater landslides that exposed further deposits of methane. Over a period of only thousands – or maybe hundreds – of years, billions of tonnes of gas were released into the ocean, and dispersed into the atmosphere. It was a vicious circle. Methane has thirty times the global-warming potential of carbon dioxide. The temperature rose all over the planet, including in the oceans, prompting the hydrates to dissociate, and setting the whole thing in motion all over again. The Earth became a gigantic oven.' Bohrmann turned to Johanson. 'The temperature in the depths reached fifteen degrees. Nowadays it's between two and four. That's a pretty major shift.'

'Disastrous for some species, but as for the rest… I guess they got off to a warm start. I see what you're saying. Next up is the extinction of mankind, I suppose?'

Sahling smiled. 'Things aren't that drastic yet. But you're right. There's reason to believe that we're currently in a phase of climatic fluctuation. The hydrate reserves in the oceans are highly volatile. That's why we're paying so much attention to your worm.'

'But what's a worm got to do with the stability of hydrates?'

'In theory, nothing. The layers of hydrate are hundreds of metres thick. The worms stay on the top layer, melt a centimetre or two of ice, and sit there contentedly with their bacteria.'

'But our worm's got vast jaws.'

'Our worm makes no sense at all. Come and see for yourself.'

They walked over towards a semi-circular control panel at the back of the room. It reminded Johanson of the control desk for Victor, but this one was significantly bigger. Most of the two dozen or so monitors had been switched on and were transmitting pictures from inside the tank. The technician on duty greeted them.

'We keep tabs on what's happening with the help of twenty-two cameras. In addition to that, we're constantly taking readings from every cubic centimetre,' explained Bohrmann. 'See those white patches on the upper row of monitors? They're hydrates. We set down two of your polychaetes just on the left here. That was yesterday morning.'

Johanson squinted up at the screens. 'I see ice, but no worms,' he said.

'Take a closer look.'

Johanson scrutinized every detail of the pictures. Suddenly he noticed in two dark patches. He pointed to them. 'What are those? Indentations in the ice?'

Sahling said something to the technician. The picture changed. All of a sudden the worms came into view.

'The dark spots are holes,' said Sahling. 'Let's look at the sequence in time-lapse.'

Johanson watched the worms wriggle over the ice. They crawled around for a bit, as though they were on the scent of something. Speeded up, their movements were alien and disturbing. On either side of their pink bodies, their bristles quivered as though they were charged.

'Now, watch carefully.'

One of the worms had stopped crawling. Wave-like movements pulsed through its body. Then it disappeared into the ice.

Johanson gave a low whistle. 'My God! It's burrowed in.'

The second worm was still on the surface, a little further to one side. Its head moved and suddenly its proboscis shot forward, revealing its jaws.

'They're eating their way into the ice!' exclaimed Johanson.

He stood, paralysed, in front of the screens. There's no reason to be shocked, he told himself. The worms live symbiotically with bacteria that break down hydrates, but they're equipped with jaws for burrowing.

The solution was obvious. The worms were trying to reach the bacteria buried deeper in the ice. He watched them, fascinated, as they dug into the hydrates, their rear ends wiggling. Then they were gone. Only the holes remained, two dark patches in the ice.

It's nothing to get worked up about, he thought. Some worm species spend their whole lives burrowing. But why would they burrow into hydrates? 'Where are they now?' he asked.

Sahling glanced at the monitor. 'They're dead.'

'Dead?' Johanson echoed.

'They suffocated. Worms need oxygen.'

'I know – that's the whole point of the symbiosis. The bacteria produce nutrients for the worm, and the worm provides oxygen for the bacteria. What went wrong?'

'They dug themselves to death. They chomped their way through the ice, fell into the pocket of methane and died.'

'Kamikaze worms,' muttered Johanson.

'It does look like suicide.'

Johanson thought for a moment. 'Unless they were thrown off-course by something.'

'Maybe. But what^? There's nothing in the hydrates that could explain such behaviour.'

'Maybe the gas pocket.'

Bohrmann scratched his chin. 'We wondered about that, but it doesn't explain why they'd dig their way to death.'

Johanson pictured the mass of wriggling worms at the bottom of the ocean. He was feeling increasingly uneasy. What would happen if millions of worms burrowed into the ice?

Bohrmann seemed to hear his thoughts. 'The worms can't destabilise the ice,' he said. 'On the seabed the hydrate layers are infinitely thicker than they are here. Even crazy creatures like these would only dent the surface. They'd manage a tenth at most before death reeled them in.'

'So, what's the next step? Will you test some more specimens?'

'We can use the worms we kept in reserve. Ideally, though, we'd like to examine them in situ. That should please Statoil. In a few weeks' time the RV Sonne will be leaving for Greenland. If we set sail a little earlier, we could stop off at the place where they first showed up and take a look.' Bohrmann shrugged 'It's not up to me, though. We'll have to wait for a decision. It was just an idea I developed with Heiko.'

Johanson glanced back at the tank and thought of the dead worms. 'It's an excellent idea,' he said.

AFTER A WHILE JOHANSON went back to the hotel to get changed. He tried to reach Lund, but she wasn't picking up. He imagined her lying in Sverdrup's arms and hung up.

Bohrmann had invited him to dinner that evening in one of Kiel's best restaurants. He went into the bathroom and inspected himself in the mirror. His beard needed trimming, he thought. It was at least two millimetres too long. Everything else was just right, though. His once-brown hair was thick and shiny, despite the strands of grey, and his eyes still twinkled beneath heavy brows. At times he found it hard to resist his own charisma. One of his female students had told him that he looked like the actor Maximilian Schell. Johanson had felt flattered – until he found out Schell was over seventy.

He rummaged through his suitcase, pulled out a zip-neck sweater and put it on, then struggled to force his suit jacket over the top. He wrapped a scarf round his neck. He didn't look well dressed, but that was how he liked it. He cultivated a scruffy look. It took him longer to achieve his dishevelled hairstyle than most people would spend on a respectable coiffure.

He flashed himself a smile in the mirror, left the hotel, and took a taxi to the restaurant.

Bohrmann was waiting for him. They had a few glasses of wine with their dinner, but eventually the conversation drifted back to the ocean. Over desert Bohrmann asked casually, 'How much do you know about Statoil's plans?'

'Only the basic details,' said Johanson. 'I'm not especially well informed about oil.'

'What are they planning? It can't be a platform – it's too far out to sea.'

'It's not a platform.'

'I don't want to pressure you and I've no idea how confidential these things are…'

'I shouldn't worry about that. I've been told, it can't be very secret.'

Bohrmann laughed. 'So, what are they building out there?'