Hollywood director James Cameron mourned a "tragic loss" after a deep-sea research vessel imploded nearly 10 kilometres beneath the surface of the Pacific Ocean.
The Nereus robotic research vehicle was exploring the Kermadec Trench, several hundred kilometres north of New Zealand, when it was crushed by the extreme water pressure.
"I feel like I've lost a friend," Cameron posted yesterday on the Facebook page of the US-based research body the Woods Hole Oceanographic Institution, which was operating the Nereus.
"Nereus was an amazing, groundbreaking robot and the only currently active vehicle that could reach the extreme depths of the ocean trenches. This is a tragic loss for deep science."
The Titanic and Avatar director, who is also a renowned deep-sea explorer, added: "They've not only lost a child, they've lost a great opportunity to explore one of the ocean's deep trenches - the last great frontier for exploration on our planet."