Ocean

“Man overboard!” The dreaded call that starts a race against time and the often treacherous sea. Sadly, the sea often wins, mainly due to reaction times. Researchers at the Technical University of Denmark (DTU) are now developing an onboard drone that aids rescues without human intervention.

A semi-submersible aquaculture rig that holds more than 14 million gallons of water – 20 Olympic swimming pools' worth – has begun operating in the waters off Hainan Province. It's expected to produce more than 4,000 tonnes of fish in its first year.

It was nine years ago that we told you about the intriguing Pioneer mini-ROV (underwater Remotely Operated Vehicle), made by Norway's Blueye Robotics. Well, it's now got not one but two more capable siblings, in the forms of the ocean-exploring X3 Ultra and X7.

It isn't easy harnessing the power of waves to generate electricity, but a Spanish engineering firm is giving it the ol' college try with a giant floating buoy. IDOM is testing its low-power wave-energy converter off the coast of Northern Spain.

Poseidon is probably still getting used to our growth from wooden boats to enormous cruise ships. Imagine his shock when he sees electric boats casually pulling up to recharge right in the middle of the sea, thanks to a new offshore charging system.

Chinese scientists have revealed plans for a new tourist-centered panoramic-view submersible that will take people on an affordable trip 3,280 feet (1,000 m) into the deep – and they say the first prototype will be ready before the end of the year.

In the South China Sea, the aqua-colored waters of an expansive shallow reef platform suddenly gives way to a near vertical shaft of vast darkness – an ocean sinkhole almost entirely devoid of oxygen and, in turn, marine life as we know it.

A team of Australian bodyboarding ratbags has managed to capture staggering footage of an extraordinary oceanic phenomenon: a place where four 12-ft (3.7-m) waves regularly converge into an oval dip, with explosive results.

Later this month, German water sports enthusiast and environmental activist Michael Walther will attempt to cross the Atlantic Ocean on an SUP. If he succeeds, he will be only the second person to ever do so.

Deep sea mining has been off limits because it's awfully hard, and because governments haven't yet firmed up regulations around extracting minerals offshore. That might soon change with The Metal Company's latest move – perhaps sooner than it should.

If you're setting out to build an underwater robot that's speedy, maneuverable and versatile, why not just copy what already works in the natural world? That's exactly what Beatbot has done, with its bio-inspired Amphibious RoboTurtle.

Researchers have prototyped sensor-packed robot bugs that mimic biological digestive systems to meet energy needs, employ a Janus interface for a steady supply of nutrients and move on the water's surface like a water strider.