Lights in the Deep: reading passage and questions

Kai pressed his nose against the cold window of the submersible and watched the blue water turn dark. The little research submarine, named Mira, carried three people: Kai's aunt Marisol, a pilot named Joss, and Kai himself. Fifteen minutes ago the surface had been bright. Now the light was fading fast, and the water outside was cold and still.

"We are in the twilight zone," said Aunt Marisol. "It starts about two hundred meters down, and only a little light reaches it." She pointed to a gauge. "Soon even that will be gone." Kai watched the blue fade to gray, and then to a blackness so deep that the lights of the submersible looked like two tiny moons.

Joss switched off the outside lamps to save power. The cabin was silent except for the hum of the machines. At first Kai saw nothing at all. He held his breath and waited. Then something blinked, a tiny blue spark, and then another. Soon the whole dark water was full of drifting sparks, as if someone had thrown a handful of stars into the sea.

"Bioluminescence," said Aunt Marisol softly. "Many animals in the deep sea make their own light." Kai leaned closer and watched with his whole body. She explained that sunlight does not reach down here, so the animals make light for themselves. "They use it to find food, to find mates and to protect themselves," she said. "Down here, light is a language."

An hour later, Joss steered the submersible lower. Out of the blackness came a fish with a glowing lure dangling in front of its mouth. The lure swayed back and forth like a tiny lantern. "An anglerfish," said Aunt Marisol. "The glowing tip holds bacteria that make light." Kai laughed. The fish was ugly and wonderful at the same time.

They passed through a snowstorm of tiny white flakes that drifted slowly down past the window. "Marine snow," said Aunt Marisol. "It is bits of food falling from the upper ocean. Many deep-sea animals eat it." Kai held out his hand to the glass, as if he could catch a flake. The ocean felt like a giant, quiet room with the lights turned low.

At last Joss turned on the lamps, and the submersible began to rise. Kai did not want to go. The deep ocean was cold and dark, but it was full of living light. "People have explored only a small part of it," said Aunt Marisol. Kai made himself a promise: someday he would come back and look again.