Oxygen, the molecule that supports intelligent life as we know it, is largely produced by plants. Whether underwater or on land, they do this by photosynthesizing carbon dioxide. However, a recent study demonstrates that oxygen can be produced without the need to live at depths inaccessible to light.

The authors of a recent publication in Nature Geoscience were collecting samples of deep ocean sediments to determine the rate of oxygen consumption at the seafloor through things like organisms or sediments that can react with oxygen. But in several of their experiments, they actually found that oxygen increased instead of decreasing as they would have expected. This led them to wonder how this oxygen was produced.

They discovered that this “dark” production of oxygen on the sea floor only appears to occur in the presence of mineral concentrates called polymetallic nodules and deposits of metals called metalliferous sediments. The authors believe the nodules contain the right mix of metals and are dense enough that an electric current can pass through them for electrolysiscreating enough energy to separate hydrogen (H) and oxygen (O) from water (H₂O).

The authors also suggest that the amount of oxygen created may fluctuate depending on the number and mix of nodules on the ocean floor.

This research team was trying to understand the implications of extracting seabed metals such as lithium, cobalt or copper, funded by an extraction company with the aim of ensuring that deep sea mining generates a net benefit for humanity and the planet. Earth system. Lithium and cobalt are used, for example, to make rechargeable batteries for cell phones, laptops and electric vehicles. Copper is essential for electrical wiring in devices such as televisions and radios, as well as for roofing and plumbing.

The investigation focused on the Clarion-Clipperton area of ​​the Pacific Ocean, a vast plain between Hawaii and Mexico where millions of tons of these metals have been found. However, scientists believe mining on this scale is potentially unpredictable and can destroy habitats vital to ocean ecosystems. Deep sea mining can also introduce plumes of harmful sediment fragile ecosystems, which leads a growing number of countries to call for a moratorium.

Dark oxygen for life

The implications of this discovery may also play a role in life elsewhere.

Oxygen is essential to complex life as we know it. Complex life evolved and developed alongside photosynthesizers, which actually produce oxygen as a waste product. However, this oxygen allows organisms to metabolisms to be much more effective than without it.

Without photosynthetic bacteria, life on Earth’s dependence on oxygen may never have occurred, in addition to the evolutionary path to biodiversity as we know it. However, this study shows that the rich nodules on the sea floor may have provided an additional source of oxygen to the biosphere, the zone of life on Earth encompassing all living organisms.

We cannot understand how these nodules may have affected evolution until we better understand how they formed. deeper in time. For now, all we really know is that these nodules themselves would have needed oxygen to form.

Studies like this show how much of the origin of life on Earth still remains a mystery.

This article was originally published on The conversation by Lewis Alcott at the University of Bristol. Read the original article here.