A robot boat and submersible has won XPRIZE to find the best new technology to map the seabed.
The surface and the underwater combination demonstrated their abilities in a timed test in the Mediterranean, landing depths down to 4 km.
In aggregate of the international GEBCO-NF Alumni team, autonomous duo is now likely to play a role in meeting the challenge "Seabed 2030".
The aim of this is to have the earth's seabed fully mapped to a high standard.
Currently, only 20% of the world's sub-topography has been resolved to an acceptable level of accuracy.
"The global science community has come together to try to face this challenge, but if we will need it, we will need new technology, says Dr Jyotika Virmani, CEO of Shell Ocean Discovery XPRIZE.
"Through this competition, I believe some of these technologies are now ready. Some are more robust than others, but with a little more R&D I think we want a number of different approaches, so we must do this, she told BBC News.
GEBCO-NF Alumni team was always a strong favorite to win the Shell Ocean Discovery XPRIZE $ 7m (£ 5.5m). The members all had extensive experience in the relevant fields.
The group triumphed by packing an existing, state-of-the-art solution with a new twist.
So Although the HUGIN Autonomous Submarine Vehicle (AUV) is an established industrial tool for echo sounding of the depths, its unprotected surface vessel (USV) which was distributed and restored parts, was developed specifically for the competition.
This boat, called Sea-Kit Maxlimer, was designed in Essex, UK.
In fact, there were headlines in another setting three weeks ago by carrying oysters and beer between Belgium and England ̵[ads1]1; the first commercial cargo runs across the North Sea by a watertight robot.
All the teams that made it to the Mediterranean Final were asked to send their un-piloted vehicles to a competition box about 15 miles (28km) from the Greek port of Kalamata.
Upon arrival, the technologies selected only had 24 hours to create a comprehensive, high resolution (5m or better) bathymetric (depth) map; and take more pictures of the seabed.
GEBCO-NF covered over 250 square kilometers in its allotted time, and returned more than 10 images of identifiable geological features.
In a gala ceremony in Monaco on Friday, the group was presented with the Grand Prize winner trophy and $ 4M. The copyright, the Kuroshio team from Japan, was awarded $ 1m.
As part of the competition, XPRIZE also ran a separate effort in collaboration with the US National Oceanic and Atmospheric Administration (NOAA).
This made teams "sniff out" a simulated pollutant in waters off Puerto Rico and track it to the source.
The prize was split between California's Junior Quest youth school and claimed $ 800,000 as the winner, and Tampa Deep Sea Xplorers, from Florida, takes $ 200,000 as a runner-up.
Both were able to lock on the pollution (in fact, just a harmless dye), but it was also unable to trace the origin in the time that was allowed.
The XPRIZE organizers jumped somewhat surprisingly on their Monaco gala by announcing an additional "Moonshot Award" worth $ 200,000.
This went to the British Team Tao, which was created by Tyneside-based Underwater Engineer Soil Machine Dynamics Ltd (SMD) and Newcastle University.
Team Tao does not meet the smallest criteria for success in the Mediterranean finals, but the judges believed that the highly innovative approach would nevertheless be highlighted for special praise.
The group has developed "Bathypelagic Excursion Modules" (BEMs) – or as team members like to call them "cubesats of the ocean". It is a reference to the miniaturized technology that is now emerging in space research
Developed from a USV, these are compact, low cost, torpedo-like devices that descend and rise into the water, using the echo sounder to map the seabed when they moves over a grid. But their up and down maneuvers allow the modules to also try the water column.
Team Tao plans to equip BEMs with multiple sensors.
Better seabed maps are needed for a number of reasons.
They are essential for navigation of course and for laying underwater cables and pipelines.
They are also important for fisheries management and conservation, because it lies around the underwater mountains as wildlife tends to gather. Each seamount is a biodiversity hotspot.
In addition, the rugged ocean surface affects the behavior of ocean currents and the vertical mixture of water.
This is information required to improve the models that forecast future climate change – because it is the oceans that play an important role in moving the heat around the planet.