During their molting season, the concentration of methyl mercury in the seawater at Año Nuevo State Reserve was 17 times higher than normal. Scientists then found the toxin inside the shedded skin and hair that had been taken for analysis.

The mercury in the elephant seals comes from the fish and mussels they consume, which themselves have been exposed to high mercury levels in the seawater.

In the past, coral research has focused on radar and sonar mapping of the seafloor. With this kit, which is being used for the first time, biological samples can also be collected for analysis.

Currently on board the Okeanos Explorer’s Hohonu Moana, the compact kit can quickly extract tissues and preserve the sample’s DNA for analysis. This enables scientists to archive large amounts of the genetic material. Doing so can reveal important information about the evolutionary relationships amongst species.

Developed by roboticists from Queensland University of Technology, this is the world's first robot designed to search and destroy (so to speak) the dreaded crown-of-thorns starfish (COTS). It does this by seeking them out, identifying them and then administering a lethal injection of bile salts.

Its creators, Dr Matthew Dunbabin and Dr Feras Dayoub, equipped the robot with GPS, stereoscopic cameras for depth perception, thrusters to improve stability, pitch-and-roll sensors as well as the pneumatic injection arm.

Back when intrepid men donned hard hats to plumb the depths, they didn’t leave the surface without a trusty sheath knife. Wood-handled beauties like the brass-encased Morse MK V are works of art, and they make a great collectors item. But I can’t imagine any reason why I’d take one underwater.