Despite the vast icy expanse of Antarctica, beneath the surrounding sea ice lies a unique ecosystem teeming with green and brown algae.
Previously accessible only to marine life or highly trained divers, these underwater algal forests are now being mapped with unprecedented detail using cutting-edge autonomous underwater vehicles.
Antarctic sea ice algae begin their growth in early spring, relying on the faint sunlight that penetrates the ice. They play a crucial role in the Antarctic food web, providing energy for krill and other small marine organisms.
Based on these measurements, scientists can predict the total growth of algae beneath the ice.
The diving drones are 8.2 feet (2.5 meters) long and are shaped like torpedoes. The devices are deployed from holes that the researchers cut into the thick ice using an oil burner and a steam drill. The carefully carved holes also happen to be an ideal entry point for hunting seals, and sometimes, the researchers have to share their space with seals and sea lions that crowd around the heaters set up to keep the holes from icing over.
Algae attached to the underside of sea ice absorb different wavelengths of light. Each torpedo-shaped drone is equipped with a radiometer to precisely measure the light absorbed by algal clusters, allowing scientists to estimate total growth beneath the ice.
