When I talk to the public about the deep sea, I am always reminded of the New Yorker’s famous 1983 cartoon, depicting a group of ladies having tea. One says, “I don’t know why I don’t care about the bottom of the ocean, but I don’t.” The thing is, many people do care about the bottom of the ocean, finding it mysterious, exciting, and – thanks to programmes like Blue Planet 2 – its beauty has been revealed. But the cartoon still resonates in that most people don’t understand why they should care. In the words of Monty Python, they may ask: what has the deep sea ever done for me?
Firstly, we should understand that society’s wellbeing is linked to the health of the deep sea through a wide range of ‘ecosystem services’. Ecosystem services are the benefits derived from ecosystems that make human life possible, such as bees pollinating crops; without bees we wouldn’t have crops, and so no food. Bees are therefore important in the ecosystem service that provides humans with food.
In a similar way, the animals that live in the deep sea play an important role in ecosystem services, such as supporting healthy and productive fisheries; provision of new medicines like antibiotics, anti-virus treatments, and anti-cancer drugs; and mitigation of climate change through locking carbon away in things like coral skeletons. We take these ecosystem services for granted, but it is the biodiversity of the natural world that make these things happen.
Deep-sea biodiversity is increasingly under threat from our activities. People are aware of some of the problems faced by our oceans. You may have seen litter on the beaches and become aware of issues around over-fishing, but people tend to think the deep sea is an untouched wilderness. While it is true that most human activities impact coastal environments, the deep sea is increasingly subject to a variety of human uses. Fishing activities reach ocean depths of 2 kilometres. Oil and gas activities have been pushing into waters more than 3 kilometres deep, with rare but well documented catastrophic consequences like the Deepwater Horizon oil platform disaster. A new industry is now taking its first steps in mining the sea bed for deep-sea mineral resources, used in the manufacture of electronic devices like mobile phones.
Additionally, climate change is affecting the deep sea in many different ways with unpredictable consequences for the animals that live there, and in turn, the ecosystem services they provide us. To compound matters, the animals that live in the deep sea may be far more sensitive to disturbance and change than shallow water animals, meaning that although the human footprint is smaller, it is more powerfully felt.
So, what has the deep sea done for us? The deep sea supports our healthy planet, and in turn support us. Our very existence depends on a healthy, functioning deep sea environment, so we must do better at looking after it.