Jack opened his mouth when he saw her approach, but then smiled, and turned back to enjoy the show himself.

“That could be an oar fish,” Mironov said.

“Or was once,” Greg responded, also getting up, quickly followed by Abby.

“They’re quite rare you know.” Mironov leant forward in his throne-like chair, leaning on his knees. “Maybe this variety has adapted for a dark-water lifestyle.”

“Very possible; it takes thousands of generations to evolve a new capability… or lose one. But the stranger thing is, we are not at any great depth just yet. In the ocean, varieties such as the flashlight fish, bristlemouth, anglerfish, and viperfish, all use bioluminescence for capturing prey, attracting mates, or signaling. But they operate well below this level. We’re still at mid-mesopelagic, and that reaches down to six hundred and fifty feet. Below that is the bathypelagic, where we’d expect the real deep-sea life.”

“How deep can they go?” Abby asked.

“I have seen them before,” Yegor rumbled. “But, yes, much deeper than this.”

Cate rested one hand on Jack’s shoulder, but snatched it away, and folded her arms. “They can get down to the abyssopelagic – the abyssal zone – that’s about thirteen thousand feet down. Down there, you might find little more than Isopods, tube worms, snail fish and a few other soft-bodied organisms. Most of them grow extremely large.”

“Deep sea gigantism,” Greg said. “For example, in the deeps, normally tiny Isopods are ten times normal size, and very aggressive. They’re usually scavengers, but when they’re big, they’ll attack and eat live prey.”

Cate nodded. “When food is scare, I guess you gotta be prepared to fight for it…” She straightened. “…and be big enough to win those fights. But then that’s it for most sea life. Below that we have the hadopelagic – the hadal zone – the deep-sea trenches. Down to twenty-eight thousand feet and counting. Who knows what’s really down there.”

Cate pulled at her collar, feeling a run of perspiration down the center of her back and under her arms. She leant forward again. “Jack, it’s getting real hot in here; what’s the outside temperature?”

Jack looked down at a small screen on his panel, quickly reading off some of the numbers. “Eighty-two degrees – yeah, damned warm.” He turned to her. “But there’re no coolers in here, only some internal heaters. Deep water is usually cold, so no one expected they’d need to stay cool.”

“Five hundred feet, leveling off.” Yegor leaned across to them. “Maybe we can increase the dehumidifier load. This will make it dryer in cabin and at least make it feel cooler.”

“Good idea.” Jack nodded. “But what about power usage; they’re damned hungry aren’t they?”

Yegor bobbed his large head. “Da, yes, but they can run for thirty hours before impacting on battery life. We should be back home in less than that.”

“Let’s do it,” Jack said, winking up at Cate. “Make us a little more comfortable, anyway.”