Ethan peered up into the glacier’s depths and saw a thin line running through the ice parallel to the horizon.
‘That’s a sedimentary layer,’ Chandler explained. ‘If we went up there and excavated it we’d find soil, twigs and leaves embedded within it, all of them three to five millions of years old. The ice here is a relatively recent geological event – prior to this, Antarctica was a tropical rainforest.’
‘You’re telling me that Antarctica was like Brazil?’ Hannah uttered in amazement.
‘Scientists routinely excavate petrified logs from the depths of glaciers just like this one that must have come from extremely large trees. We’re even able to slice into the fossil trees and count the rings demarking their growth. The most amazing thing about that is the requirement for many of those species to have coped with the Antarctic winter, during which it’s dark for six months of the year.’
‘Trees grow through photosynthesis don’t they?’ Ethan said. ‘Wouldn’t they die?’
‘Experiments at the University of Sheffield in the United Kingdom showed that planets like the Ginkgo, an ancient species considered a “living fossil” by science, could survive in simulated Antarctic conditions quite well. Although they used up food stores in the winter, they more than made up for this by their ability to photosynthesise twenty four hours a day in the summer.’
Saunders ducked under the tree and moved on, Ethan following as Hannah spoke to Chandler behind him.
‘So if Antarctica was a normal land mass before the ice, then wouldn’t it have had animals living on it?’
‘Many,’ Chandler confirmed, ‘and as we’re talking about a period from one hundred million years ago, then there would have been dinosaurs roaming this continent just like any other.’
‘Dinosaurs?’ Hannah echoed. ‘Seriously?’
‘Absolutely,’ Chandler said. ‘Researchers at the Victoria Museum in Australia have found many dinosaur fossils in southern Australia at a location that was once positioned just off the east coast of Antarctica. Their work has shown that not only did dinosaurs live on Antarctica, but that they did so year-round. Specimens of the species
Leaellynasaura
showed adaptions of the skull which indicate that the animal had enlarged optic lobes, designed to offer acute night vision well suited to the prolonged winter darkness.’
Hannah smiled nervously.
‘Let’s hope that none of them are left wandering about down here then, shall we?’
Saunders chuckled.
‘The species died out tens of millions of years ago, and was a plant eater no bigger than a kangaroo,’ he said. ‘You’d have had nothing to fear from it.’
Ahead of them, Lieutenant Riggs slowed as he looked down at a scanner he held in his hand.
‘Well, something’s ahead of us,’ he said. ‘I’m getting a much stronger signal now. We’re close.’
***
XXI
The ice channel’s water glistened in the glare from the team’s mounted flashlights as Ethan followed Saunders over a series of rugged, icy boulders blocking their path, likely deposited by the fast moving waters that had forged the tunnel.
Ethan could see that the water itself was still icy cold, possessed of a faint blue hue that betrayed its frigid depths as not much above freezing.
‘This water,’ he said, glancing back at Saunders, ‘how come it’s warmer than the rest? Something must be heating it?’
Ethan found it tough to believe that rainforests haunted by small dinosaurs once flourished where the thick ice sheets now existed, but he knew that the evidence of science never lied.
‘The geological record provides irrefutable evidence of dramatic climate fluctuations that have occurred throughout our planet’s history,’ Chandler replied, scrambling over a rocky boulder. ‘In the past fifty years the Antarctic Peninsula has warmed by nearly three degrees Centigrade, faster than any other part of the world. These ice channels may now be common beneath the ice sheets but normally we just can’t see them, and so we can’t tell if they’re flowing in from the oceans around Antarctica somehow, or are coming from within it and spilling into the oceans around the continent instead.’
Ethan surveyed the depths of the tunnel ahead thoughtfully.
‘Water doesn’t typically flow into continents from outside, it falls as rain or snow.’
‘Correct,’ Chandler replied, ‘and that leaves only one possible cause of the warming we’re seeing here: volcanism.’
‘There are volcanoes here too?’ Hannah uttered. ‘You’re really selling the place.’
‘Mount Erebus is currently the most active volcano in Antarctica and is the current eruptive zone of the Erebus hotspot. The summit contains a persistent convecting phonolitic lava lake, one of only five long-lasting lava lakes on the planet. Scientific study of the volcano is also facilitated by its proximity to McMurdo Station. Mount Erebus is classified as a polygenetic stratovolcano – that is that the bottom half of the volcano is a shield and the top half is a stratocone like most volcanoes. The whole system has been active for some time.’
Ethan tried not to consider what that meant for the expedition, currently some two hundred feet beneath the ice of an unstable glacier being weakened by volcanically warmed water rushing by just feet from where they walked. He was about to change the subject when Saunders called out.
‘Hey, you guys see that?’
Ethan looked up ahead, and in the gloom he saw something shimmering against the ice. The team stopped and stared ahead in silence at the glistening light, as though a star had fallen through the ice and was sparkling where it had become trapped. Ethan squinted, tried not to look directly at the glow but to one side of it where his eyes could detect it more easily.
‘Is it a reflection of some kind, from our lights?’ Hannah asked.
Lieutenant Riggs called out. ‘Everybody shut off your lights.’
Ethan obeyed instantly, turning his LED light off as did everybody else in the team. The tunnel was plunged into an absolute darkness so deep that Ethan was forced to put a gloved hand onto the ice wall alongside him to keep his balance. He peered into the distance as his eyes adjusted to the darkness, and saw the soft blue glow spread across the tunnel far ahead of them.
‘What’s causing that?’
Hannah’s voice sounded disembodied in the blackness, echoing back and forth within the confines of the chamber as Ethan noticed the glow getting brighter, his eyes adjusting quickly to the gloom.
Then Saunders’ voice echoed from somewhere ahead.
‘It’s getting brighter, and it’s coming closer.’
Ethan’s eyes widened as he realized that the light was closing in on them, illuminating the tunnel around it in a blue halo of light. Lieutenant Riggs reacted instantly.
‘Everybody down, stand by!’
Ethan crouched down, one gloved hand resting on the 9mm pistol holstered on his belt as he watched the light growing in intensity before them. Like the hazy halo of a blue sunrise it reflected off the ice of the tunnel and seemed to sparkle as though alive, shimmering through the glassy ice. Ethan’s first fear that it was some kind of man-made light attached to a craft on the water began to dissolve as he realized that the light had no natural proximal source.
‘I can’t see a target on the water,’ Saunders whispered harshly, sighting the glow down the barrel of his M-16 rifle’s telescopic sight.
It was Lieutenant Riggs who replied.
‘It’s not on the water,’ he said. ‘It
is
the water.’
Ethan stared in amazement as from the darkness the water flowing through the tunnel suddenly began to glow a bright blue, illuminating the ice cave around the team with enough light for Ethan to make out the way far ahead.
‘What the hell is going on?’ Hannah asked, her voice hushed as they watched the bizarrely glowing water swirl past them in flickering eddies of light.
Doctor Chandler stepped forward and crouched at the edge of the flow as he peered down into the water.
‘It’s mareel,’ he said as he identified the source of the glow. ‘The water’s filled with bioluminescent bacteria and dinoflagellates called
Noctiluca scintillans,
or perhaps a similar species called
Vibrio harveyi
. I’ve heard of Navy pilots coming in to land on aircraft carriers at night being helped by this glow of the water in the wake of the ship, the glowing wake guiding them in the absence of any other light source. It’s caused by a disturbance in the water and is often seen by mariners out in the oceans at night.’
Ethan stared down at the glowing water, which was now illuminating the team’s faces in a neon blue light as though they were all staring at computer monitors. The ice cave around them was bathed in the blue glow, the ice sparkling vibrantly above their heads.
‘What’s causing the disturbance?’ he asked.
Chandler shook his head.
‘I’ve heard of the discharge of pollutants into water being capable of generating algae blooms that then glow as a result of the chemicals on which they feed,’ he said thoughtfully as he looked up river toward the glowing depths of the cave. ‘But the ice below this glacier should be pristine unless the volcano itself is discharging chemicals into the water.’
Lieutenant Riggs peered into the distant tunnels.
‘You think that it’s likely to erupt soon?’
Chandler shook his head.
‘Mount Erebus is notable for what are called ice fumeroles, ice towers that form around gases that escape from vents in the surface of the volcano. The ice caves associated with the fumaroles, like the one we’re standing in, are usually dark because polar alpine environments are starved in organics. The life is sparse, mainly bacteria and fungi which is of special interest for studying
oligotrophs
- organisms that can survive on minimal amounts of resources.’
‘That’s not what I asked,’ Riggs snapped.
Chandler glared at the soldier, apparently unintimidated.
‘I hadn’t finished. The caves on Erebus are of especial interest for astrobiology as most surface caves are influenced by human activities, or by organics from the surface brought in by animals or ground water. The caves at Erebus are high altitude, yet accessible for study. There is no chance of photosynthetic based organics or of animals in a food chain based on photosynthetic life, and no overlying soil to wash down into them. Organics can only come from the atmosphere, or from ice algae that grow on the surface in summer, which may eventually find their way into caves like this one through burial and melting. As a result most micro-organisms here are chemolithoautotrophic - microbes like
Chloroflexi
and
Acidobacteria
that get all of their energy from chemical reactions with the rocks and don’t depend on any other lifeforms to survive.’ Chandler shook his head. ‘But they would not be present in such numbers and concentrations through natural sources as we’re seeing here. Something must have happened upstream to cause this.’
Lieutenant Riggs pushed his point.
‘Something man-made, like a chemical leak?’
Chandler stood up and nodded.
‘Something exactly like that,’ he agreed. ‘This cave could become highly poisonous at any time, and we know that it has broken close to the surface above us in recent months, perhaps recent weeks. If it floods again…’
‘We get the picture,’ Riggs cut in. ‘Keep moving.’
Ethan followed Saunders as they picked their way forward through the tunnel, the glowing waters now illuminating their path as they advanced ever deeper into the glacier. Ethan knew that the water had to be flowing downhill to reach the ocean somewhere on the Antarctic coast, so technically they were going uphill. Thus, the immense mass of ice above them would likely be getting thicker with every step that they took. He had read somewhere that at its thickest the Antarctic ice sheet was three miles deep, all of it snow compacted until it became as hard as granite. The thought of the warm water weakening that immense mass of ice and bringing it down on the team, either crushing them instantly to death or trapping them to freeze for all eternity was too terrible to contemplate, so he put his head down and pushed on, Hannah just behind him.
They walked for several more minutes until Saunders’ harsh voice snapped just loudly enough to be heard over the rushing water.
‘Enemy!’
***
XXII
Ethan’s response was almost as swift as that of the SEALS. In an instant he dropped into a crouch, his pistol appearing in his hand as he drew it and aimed alongside Saunders, who had dropped into a similar crouch and was holding his rifle tight into his shoulder and aiming down the tunnels. To Ethan’s surprise and delight he saw Hannah’s pistol just to the right of his head, the former FBI agent covering him and aiming in the same direction.
The rest of the SEAL team had mirrored their actions, all eight of their rifles aiming over or around their civilian charges as they sought the enemy that Saunders had seen.
Ethan peered into the shimmering blue depths ahead of them and saw a figure standing on the ledge, the clear shape of a rifle in his grasp. Ethan aimed at the figure as he heard Saunders challenge the man.
‘On your knees, put your weapon down
now
!’
Ethan watched the figure, waiting for him to capitulate as he identified the soldiers massed before him, but the man was either suicidal or fearless for he did not move.
‘Last chance!’ Saunders snapped. ‘Down on the ground!’
The command echoed above the freezing water rushing by them, rolling into the empty darkness, and was answered with silence. Ethan peered at the shadowy figure for a few moments longer and then Saunders fired a single shot.
The crack of the rifle was ear shatteringly loud in the tunnel’s confines, and even in the faint bioluminescence of the blue water he saw the shot impact the man in the center of his chest with a sharp secondary crack and a brief flash of light.
To his amazement, the figure did not move and Saunders lowered his rifle and looked over his shoulder, somewhat confused.
‘Sorry, trick of the light I guess.’
Ethan frowned. ‘Had me fooled too.’