The deep sea, by far the largest habitat on our planet, is virtually unexplored: humanity knows more about the far side of the moon than about Earth's oceans. Only 20% of the deep sea has been mapped – yet it covers almost two-thirds of our planet's surface. A team led by Katherine Bell has now investigated just how profound our ignorance actually is.
To date, deep-sea expeditions have visually recorded only 0.001%. To put this in perspective: one thousandth of one per cent, or one hundred-thousandth.
Furthermore, these surveys are highly unevenly distributed: the analysis of 44,000 deep-sea dives since 1958 reveals that nearly two-thirds took place in areas belonging to Japan, New Zealand, and the USA (within their Exclusive Economic Zones, EEZ, i.e. the 200-nautical-mile zones). When France and Germany are included, the expeditions of these five countries account for 95% of all deep-sea dives.
Consequently, we have a highly distorted picture of this 336 million square kilometre habitat. It is undoubtedly far more diverse than this minimal snapshot suggests: Belgium is ten times larger. While several canyons and seamounts are well researched, the vast plains in between remain one colossal blank space on the world ocean map.
What this makes clear is that with such limited knowledge, we cannot even define the necessary safe boundaries for our activities (“how far can we go before we jeopardise something?”). If we do not know what is there, we cannot know what we are damaging or destroying.
How deep-sea mining can be promoted or permitted under these circumstances remains incomprehensible. The consequences could be severe – and here too, our knowledge is virtually non-existent: how does the deep sea, as the most critical carbon sink and climate regulator, influence us? What habitats for a largely undiscovered fauna are affected by this exploitation? We do not know. Therefore, hands off the deep sea!
