The oceans are the biggest, wildest, least understood part of the planet. But we’re getting to know them better every day, thanks to a host of technologies that are fathoming the depths in new and inventive ways.
Some researchers are capturing things from the sea and transporting them into the lab to study in detail; others are rigging the oceans with novel sensors and devices, or probing them with algorithms. Together, these approaches are offering brand new views of the underwater world, at a time when it’s never been more important to decipher the inner workings of the oceans.
From coral reefs to deep-dwelling jellies, the oceans’ living inhabitants face greater threats from human activities than ever before. The seas are polluted and overfished, marine habitats are being destroyed, and new impacts – such as deep-sea mining – are fast approaching.
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It’s also becoming increasingly clear just how critical the oceans are for the rest of life on Earth. These enormous, ever-shifting waters play a vital role in weather and climate systems, provide food and livelihoods for human populations around the world, and are home to great swathes of unknown biodiversity. In order to understand and protect life on this planet, we have to look to the oceans.
Virtual e-reef builders
Not so long ago, the main way that marine biologists studied coral reefs was to scuba dive for an hour or so at a time and note down what they saw on waterproof slates. Now, during a single dive, they can take photographs that can be stitched together into an intricate, three-dimensional view of the reef.
“It’s underwater virtual reality,” says Prof Stuart Sandin, a marine biologist at Scripps Institution of Oceanography, UC San Diego. “It makes you feel like you’re immersed.”
Using a system with two cameras rigged at different angles, a diver swims up and down a reef as if they are ‘mowing the lawn’. Around 3,000 images taken from a standard 10 x 10m plot are then analysed by computer using a technique known as ‘structure from motion.
The result for a 10 x 10m plot is a three-dimensional digital model of the reef, made up of a billion coloured dots.
The technique, which took Sandin years to develop by collaborating with teams of computer scientists and engineers, is now being rolled out around the world.
So far, 30 hectares of reef have been mapped, equivalent to dozens of city blocks, at a resolution of one millimetre. Besides producing stunning underwater vistas, all sorts of valuable information can be extracted from these e-reefs.
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At Boston University, undergraduate student researcher Coretta Granberry meticulously traces on a digital tablet the outlines of individual corals, so she can calculate their areas and make comparisons over time. “You get a very detailed, intimate image of the reef and how everything is connected,” she says.
The corals she studies are growing thousands of miles away, in the Phoenix Islands in the middle of the Pacific. Her professor, Dr Randi Rotjan, leads expeditions every three to five years to these extremely remote reefs. “Out there, the closest people to you are on the International Space Station,” says Rotjan.