23 THE FIRST NIGHT

CHAPTER 23 THE FIRST NIGHT The water was shallow enough that Roz could watch the sun moving across the sky. While she marched along the bottom, the bright ball of light wiggled and wobbled through the wavy surface overhead and sank toward the western horizon. The water turned orange and then purple and then black. Roz's first night in the ocean had begun. The robot activated her headlights—click—and light beamed out from her eyes. To one side, fish darted away. To the other side, the seabed dropped sharply into the deep ocean. And that's when Roz noticed the migration. At the very edge of her vision, where her light beams faded to darkness, there was movement. Up from the deep came hundreds, thousands, millions of sea creatures. Most were microscopic, the tiniest life- forms imaginable. Others were bigger, like fish and squid and bizarre jelly creatures. Each night, they ascended to the starlight. Then before the sun returned, they descended back into the deep. Around the world, countless sea creatures made this great vertical

migration every night. Their movement churned the water, spreading nutrients throughout the depths, helping to keep the oceans healthy. And now our robot got to witness a small part of this natural wonder for herself. At that time of year, the nights were short, and a few brief hours after the sun had set in the west, it was already rising in the east. The migratory sea creatures disappeared back down into the abyss. The water turned purple and then orange and then bright blue. Roz's first night in the ocean had ended.