‘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.’
It was Hannah who spoke up in the SEAL’s defense.
‘That’s no trick of the light, stay sharp.’
The SEALS did not respond except to keep their weapons trained on the shadowy figure and begin advancing as one, edging their away around the scientists crouched on the path and moving toward the figure.
Ethan moved into position behind them with Hannah alongside him as they crept forward and began to emerge onto a slender ledge that jutted out on a curve in the tunnel, where the water had once washed around a smooth bend and scoured from the ice a wider platform. Ethan lowered his pistol as he saw the SEALs relax, and then his jaw dropped as he realized what Saunders had seen.
The light from the water was piercing the ice walls of the tunnel, creating an illusion of open air instead of the solid ice that confronted them. There, trapped within that ice was the shape of a man, a rifle held in his long dead hands. Ethan heard Hannah gasp as she noted the uniform the man was wearing.