Electric robots are mapping the seafloor, Earth's last frontier

Seatrec and Bedrock Ocean Exploration are two startups taking electric robots to new depths in an attempt to map the ocean floor.

Getting a fuller picture would enable us to navigate ships more safely, create more accurate climate models, lay down telecommunication cables, build offshore windfarms and protect marine species -- all part of what's known as the "blue economy," projected to be worth $3 trillion by 2030.

Underwater robotic vehicles equipped with sensors are helping gather that data quicker and more cheaply than ever before. But many of these vehicles rely on batteries with a limited lifespan, and need to return to a boat or the shore to recharge, making it difficult for them to map more remote parts of the sea.