Speaker spotlight: Dr Helen Scales

Helen Scales is a diver, surfer, broadcaster and writer who, as a marine biologist, has spent hundreds of hours underwater watching fish. She has spoken about the mysteries of the deep sea with Robin Ince and Brian Cox on BBC Radio 4's The Infinite Monkey Cage and donated an imaginary tank of seahorses to The Museum of Curiosity. On 28th March at 3-4pm at the Cambridge Festival she will talk about her new book, The Brilliant Abyss, which draws on the collections at the Zoology Museum in Cambridge to illuminate the majesty and marvels of the deep sea.

Can you describe how fast the pace of discovery about the deep ocean has been in the last decade?

We’ve seen a huge acceleration in deep sea discoveries in the last decade or so, thanks to a suite of powerful new technologies that give scientists access to the deep ocean. Remotely operated vehicles, first developed in the oil and gas offshore industry, offer a real-time view of the deep with high definition video feed from thousands of metres underwater. Autonomous devices are deployed and left to wander the ocean, gathering data by themselves. All in all, we know more than ever before about the deep ocean, what lives there and how this enormous living biome works.

How does what we are finding compare with previous hypotheses on life in the deep ocean?

Not so very long ago, in the mid-to-late nineteenth century, it was generally thought nothing at all lives in the deep ocean. Below the top few hundred metres, the ocean was just a vast, empty void. There’s no light down there, very little food, it’s cold and there’s the extreme pressure to deal with, so how could anything survive? Now, we know life occupies the entire ocean, all the way into the very greatest depths. There are animals and microbes living at the bottom of trenches in the hadal zone, including the very deepest, the Mariana Trench, around 11 kilometres beneath the waves.

Can you single out any discovery which highlights the potential for good from our exploration of the deep ocean?

Recently, scientists from Plymouth University discovered a chemical in a deep ocean sponge that kills the superbug MRSA. Time will tell whether or not that particular discovery leads to a new antibiotic, but it’s one of hundreds of new compounds being discovered in the deep ocean that are showing enormous potential for developing a new generation of pharmaceuticals. Deep ocean corals and sponges, in particular, are brimming with potent chemicals. Just as plants on land have traditionally been a tremendous source of medicines, corals and sponges have similarly evolved chemical defences against attack, and these are precisely the kinds of chemicals that are useful as agents against all sorts of human pathogens. In the years ahead, I think we will start seeing a lot more deep-inspired medicines in modern treatments.

What can the deep ocean tell us about climate change?

The deep ocean tells us that climate change is impacting our entire planet, and also that we have the ocean to thank for averting a devastating rise in temperature. More than 90 percent of the extra heat trapped by human-emitted carbon dioxide has been taken up by the oceans. Without the ocean’s vast volume of water, global temperatures on land would already be over 30 degrees Celsius higher than preindustrial times.

The deep also offers incontrovertible proof - should you need it - that anthropogenic greenhouse gases are driving climate change. A 2020 study revealed that the temperature in the top 2,000 metres of the ocean has been relentlessly rising since the 1980s. The only reasonable explanation for this temperature rise is those extra heat-trapping gases human activities are releasing.

How can we best protect the ocean from potentially disastrous exploitation?

There are two key things that need to happen.

Deep-sea trawling on giant underwater volcanoes, called seamounts, needs to be brought to a halt. This form of fishing has devastating impacts, stripping away corals that have been growing for hundreds and thousands of years, and demolishing ecosystems that show few signs of recovery many decades later. Most of these fisheries are only marginally economically viable because of substantial government subsidies. Take those subsidies away and deep-sea trawl fisheries would quickly become unprofitable.

Various countries and corporations are vying to become the first deep-sea miners for valuable minerals and metals. Many are declaring seabed metals to be the key for a green future, to build solar panels, wind turbines and electric car batteries. But scientific studies are warning the seabed mines would destroy vital ecosystems, destabilise ocean health and potentially make climate change even worse. There are alternatives to seabed metals that don’t risk triggering new and unknown threats to the planet and technological advances could reduce humanity’s dependence on these metals. Deep-sea mining is not a fait accompli and there are growing calls for a global moratorium.