How we can protect the vast living space of the deep ocean

‘Speak, thou vast and venerable head … Of all divers, thou hast dived the deepest. That head upon which the upper sun now gleams, has moved amid this world’s foundations.’ So says Captain Ahab as he peers over the side of his whaling ship, Pequod, at the head of a sperm whale.

Herman Melville would have been astounded to know what sperm whales encounter as they hunt in the deep sea. When Moby Dick (1851) was published, the scientific establishment still generally held the view that below the upper 300 fathoms (around 550 metres) the ocean was empty of life. In truth, the deep is not only a ghoulish realm of shipwreck and pirate victims, as Melville imagined, it’s home to a tremendous panoply of strange animals. Sperm whales dive well past the 200-metre mark – the official beginning of the deep – to at least 2,000 metres. As they chase after enormous squid, sperm whales pass so many lifeforms unlike anything on land.

The rules of life are very different in this pitch-dark, chilled, high-pressure environment, leading evolution down different paths. There are intricate, jelly-based creatures illuminated by their own twinkling lights, and gossamer worms spinning in tight, twirling circles. There are fish that look like sock puppets, their mouths unfolding to preposterous proportions to swallow whatever prey comes by. Bone-eating worms with red tufted gills and plant-like roots await the bodies of sunken dead whales and their stripped-back bones, after the scavenging crabs, sharks and snails have taken turns at the feast that falls from above.

Life in the deep goes far beyond the reach of sperm whales – all the way to the very bottom of the sea in fact. Tumbling down from the edges of continental shelves in every named ocean, the deep has an average depth of around 4 km and drops into trenches almost 11 km deep. In total, the deep ocean is roughly 1 billion cubic km in size and makes up roughly 95 per cent of the available living space on Earth. It’s tempting to assume the deep is too big and too remote for humans to impact in any meaningful way, and for all forms of deep-sea exploitation to be insignificant on a planetary scale. But those assumptions are simply wrong.

Hunting for sperm whales, from Melville’s time into the 20th century, was the first global industry to exploit the deep ocean. Sperm whales are air breathers but in truth they’re denizens of the deep that spend three-quarters of their lives hundreds of metres underwater. In the 20th century alone, at least 760,000 sperm whales were slaughtered, more than twice the number thought to exist today. The loss of so many whales was a catastrophe for the species and also altered the functioning of the planet. Sperm whales are one of many living elements of the global carbon pump that draws carbon dioxide out of the atmosphere and stores it in the deep ocean for millennia. During brief rests at the surface between dives, sperm whales defecate and fertilise blooms of carbon-fixing phytoplankton. Some of these minute algae die and sink into the abyss, clumped in particles known as marine ‘snow’ and taking carbon with them. Before industrial whaling, sperm whales removed millions of tonnes of carbon from the atmosphere each year, a service to climate regulation that has become drastically diminished.

The whale massacre did, however, come to an end before all the whales were gone. In 1986, a moratorium banned the commercial hunt for all the great whales, including sperm whales. Within a few short years, whales were no longer an industrial resource to be exploited but cherished wildlife deemed worthy of protection.

The history of whaling is a stark warning of the damage people can cause to the living world. Perhaps more importantly, it’s a rare reminder that we humans can change our minds over what is important and worth looking after, even in most distant, unseen places such as the deep ocean. We’ve done it before, and we now need to do it again.

The deep is under grave t

   d’aprés : aeon.co