It’s been a year since Ocean Gate, the catastrophic incident involving the commercial Titan submarine brought into question the risks, ethics and future of underwater exploration. It has been a week since the recent discovery of “dark oxygen” modules on the ocean floor, emphasising the untold majesty of what lies below, and what might still be left to discover. At the intersection of these two events, the Concrete Science Section is going on a deep (ish) dive into the past, present, and future potential of deep-sea exploration.  

As of June 2024, only 26.1% of the ocean (which covers 70% of Earth’s surface) is mapped. The deepest point, plunging over 11km below sea level, lies the Challenger Deep in the Mariana Trench, first discovered in 1875 during the expedition of the eponymous “HMS Challenger”. Using 291km of Italian hemp rope, 492 soundings were completed, with the expedition discovering over 4,500 new marine species.  

It would take only another 85 years for the first manned vessel to reach the ocean’s depth, in the two-man bathyscaphe Trieste in 1960. A landmark victory in deep-sea engineering, the next of which would follow shortly behind in Alvin, the 1964 vessel still used today. It was in Alvin in which the revolutionary discovery of hydrothermal vents was made in the late 70s.  The discovery of these vents challenged our understanding of life on Earth, confirming the theory of chemosynthesis (using molecules with carbon in for energy instead of sunlight), proving life could be sustained without the sun. From the bottom of the ocean, this radical change in understanding extends its influence to the outer expanses of space, moulding theories about, and the search for, extra-terrestrial life. 

 Since then, exploration has taken advantage of the development of remotely operated and autonomous vehicles, exploring inaccessible and hazardous regions without endangering human lives, the grisly consequences of which were demonstrated one year ago, when the commercially operated Titan submersible (owned by OceanGate) imploded, resulting in 5 fatalities. The failure of the vehicle underscored alarming gaps in regulation along with concerns about the ethics of such trips, and the actions of the wealthy. While criticised for weak safety standards now, it was still the first privately owned vehicle capable of reaching such depths and made several successful dives despite having such a unique construction (such as using carbon fibre instead of the industry standard titanium), which highlights just how much room is left for innovation in the engineering aspect of the industry. 

Thus the story catches up with modern day, and the new discovery of dark oxygen – potato sized nodules acting like batteries on the sea floor, electrolysing (using electricity to force a chemical reaction) water molecules and producing oxygen deep in the water, without photosynthesis. The nodules have been the jewel of the eye of deep-sea mining industries, but the discovery of their oxygen production implies this could cause catastrophic consequences for delicate marine ecosystems. If proven true and further researched, it could have an impact comparable to that of geothermal vents – with a hypothesis they could be what sparked life on Earth.  

In a similar way to which the Titan disaster emphasised the danger of deep-sea exploration, the discovery of dark oxygen has reminded us of its rich potential, of which the ambitious Seabed 2030 is attempting to unlock. The project, recognised as a flagship programme of the UN developed “Decade of Ocean Science for Sustainable Development”, aims to produce a “definitive map” of the ocean, accessible to all, by the year 2030. Indeed, progress of the project is immediately seen, comparing the 6% mapping at the project’s initiation in 2017 to the 26.1% announced on this years “World Hydrography Day”. This mapping of our oceans will not just increase global understanding of the ocean floor, but have wide practical applications, such as navigation, resource management, disaster prevention, and aid in environmental protection. Reactions across differing industries show the importance of such projects: commercial mining companies and conservation groups alike anticipate the outcome of the project, with benefits clear, but concerns it will present an easy “treasure map” for harmful mining practices and resource disputes.  

For those looking for a career in marine sciences, the ongoing discoveries and advancements suggest the field is far from slowing down, with the ocean still representing Earths final frontier. In spite of the risks our hubris can bring, continued exploration holds immense potential for new discoveries, deeper understanding and solutions to some of the most pressing global challenges – if we commit to protecting it.  

Photo credits: Wikimedia Commons