The Pressure Drop

The Pacific looked bigger from a thousand feet up. Polly tilted her head into the wind. Her glasses had slid down her beak a little; she shook them back into place and went on watching. Far below, a small white ship was cutting south-west from Guam. From this height its wake trailed behind it like a chalk line drawn across blue paper.

She descended in long, easy spirals. The deck below was busy with figures in orange jackets, and lashed to it was the submersible, silver and blunt, about the size of a small minivan. Polly came in low.

The salt air was warm and heavy, the diesel exhaust sharp in her green-feathered chest. She tucked her blue-teal wings and landed on the railing near the bow, where the ship's name was painted in tall white letters: PRESSURE DROP. The brass was warm under her yellow feet. Her glasses caught the last of the afternoon light.

The crew did not seem to notice her. They were busy with cables and crates and a slow, careful choreography that suggested they had done all this before. Polly preferred to be ignored at first. It made watching easier.

She cocked her green head at the submersible. The thing was almost spherical at its core, with skids and floats grafted to the outside, looking less like a submarine and more like a steel pumpkin with intentions. Above the hatch, in small black letters: DSV LIMITING FACTOR.

A young engineer was running a checklist on a clipboard. He spoke quietly, almost as if to himself: "Sphere pressure-tested. Trim weights confirmed. Battery state ninety-eight percent." Polly memorised the words the way she memorised birdcalls.

A coiled cable as thick as her own neck lay on the deck near her feet. Two crew members spoke a kind of half-Spanish, half-English she did not entirely follow, laughing as they wound it onto a drum the size of a wheelbarrow.

The sun was setting fast. Off to the east, the sky had taken on the colour of a peach. Polly hopped along the railing to keep the sun in view, the wood warm under her yellow feet.

A cook stepped out of the galley for a cigarette, wiped his hands on a white apron, and squinted at the sky. He did not see Polly. She watched him, and he watched the horizon, and the only sound for a long moment was the slow slap of water against the hull.

The light went orange, then red, then went out altogether. Floodlights hummed on along the deck. The submersible's silver skin reflected them in patches. Polly fluffed her feathers against the cooling air.

In every direction, no land. Below the hull, somewhere down in the dark, the Mariana Trench began: a long, narrow scar in the seabed, dropping more than ten kilometres into a place no sunlight had ever reached.

She tucked her head under her wing. Tomorrow, the descent.