Roughly 90% of the ocean is taken up by the deep sea—any ocean area below 200 meters (656 feet) in depth—making it one of the largest ecosystems on the planet. These cold, dark waters contain extensive marine biodiversity, uniquely adapted to extreme conditions, yet humans have explored only a tiny fraction of this crucial environment.
Despite our limited understanding of the deep sea, several countries and private companies are pushing for the international community to allow commercial-scale mining on the ocean floor for raw materials—such as cobalt and nickel—that could be used to produce batteries, advanced electronics, and renewable energy technologies.
However, many scientists and policy experts believe that greater precautions must be taken as human activities continue to expand into these delicate habitats.
Deep-sea biologist and 2022 Pew marine fellow Diva Amon, director and founder of the nonprofit group SpeSeas and science adviser at the Benioff Ocean Science Laboratory at the University of California, Santa Barbara, is among those who argue that deep-sea mining could lead to irreversible environmental damage—and that further study of the deep ocean is needed to fully understand any potential environmental ramifications.
This interview with Amon has been edited for clarity and length.
A. The deep ocean is essential to us being here on this planet. Deep-sea biodiversity has critical functions that are linked to ecosystem services, such as support for the fisheries that billions of people around the world rely on as their primary source of protein. It also helps with climate regulation and provides nonrenewable resources. However, I think the role that is often overlooked is our cultural connection to the deep ocean. For example, it’s a huge source of inspiration for movies, books, and art. And there is just beginning to be a realization that this ecosystem has a spiritual significance to communities around the world. There are a lot of ways that the deep sea impacts us every day that we don’t even realize.
A. We have better maps of the moon, Mars, and Venus than we do of our ocean floor. There are likely hundreds of thousands of species waiting to be discovered, which means we still have a lot of work to do just to understand and answer the basic question of “What lives there?” And knowing the answer to that question is vital to understanding the ecology of these animals—how they live and what role they play.
A. We need a robust understanding of this environment to be able to make informed decisions about what constitutes irreversible harm or significant adverse change, and to then know how to mitigate it; and if we can’t mitigate it, whether we, humankind, are OK with that. To be able to answer those questions, we need to understand what’s there, how it works, and how it will potentially be impacted.
A. Several colleagues and I started SpeSeas because we saw that, while Trinidad and Tobago—where SpeSeas is based—uses the ocean a lot, it’s mainly in an extractive and recreational way. Our organization is helping to fill a critical gap by conducting marine research and then using it to help increase ocean literacy, as well as to advocate for effective policy change toward stewardship of our ocean. As part of my Pew fellowship, we plan to visit schools to share about the deep ocean as well as to open conversations with stakeholders throughout the country.
A. The deep ocean is incredible, but it’s also extremely fragile. Life in the deep ocean takes place on remarkably slow timescales that are very different to what you and I are used to. Animals move slowly, grow slowly, reproduce slowly, and recover from impact slowly. The expansion of human activities into the deep ocean is already happening, so we need to take precautions and provide clear scientific guidance to decision-makers about potential impacts.
A. We’ve dumped our trash in the deep ocean for centuries and fished it for decades. Now there’s the possibility of deep-sea mining, which may take place on an enormous scale. And the methods being projected for this activity will cause long-lasting or possibly even irreversible impacts. We will not see ecosystems recover except over centuries or millennia, if at all. The projected spatial and temporal scales of deep-sea mining impacts are at odds with the sustainable use of resources and ecosystems. So we need to think very carefully about how we’re going to move forward in the deep ocean, given that it’s such a lifeline for the planet.
A. That’s hard to answer, because on every research cruise, we’re exploring and studying places that no one else has ever been, so I’m constantly surprised and awed by what we come across. Life in the deep ocean has been evolving over millions of years—those species aren’t just surviving under crushing pressure, in the absence of sunlight and in near-freezing temperatures; they’re thriving.
A. The deep ocean is not an ecosystem that many of us will ever interact with directly. Still, we need to think carefully about our actions, because every single one has an impact somewhere. For example, scientists have found microplastics in every part of the deep ocean that they’ve explored, so the plastic bag you pick up at the store may end up down there in the future. The deep ocean is out of sight and out of mind for most, but it is absolutely under pressure from us.
The most important thing I would say is that the destructive industries trying to exploit the deep ocean benefit from how obscure the deep sea is. So we need to bring the deep ocean, its wonders, its importance, and its vulnerability to the hearts and minds of as many people as possible. If you do anything after reading this article, go and tell someone something you’ve learned about the deep ocean and encourage them to learn more.