Setting out to look for deep-sea creatures, a team of researchers were in for a surprise to find mysterious objects on the seafloor of the Atlantic waters around 5 000 meters deep. While exploring the seafloor and taking pictures, they noticed that their gear, known as an epibenthic sled, that was used to collect samples was getting stuck onto unknown things along the seabed. Later, when the equipment returned to the surface, they found that the reason behind was a bunch of manganese nodules from an extremely large deposit – the largest ever discovered by humans.
The epibenthic sled used to capture both samples and pictures from the seabed. Photo credits: Thomas Walter.
The scientists were bewildered at such a finding. The lead researcher, Colin Devey, said in a press release: “We did not expect that at this point“.
Images taken by the epibenthic sled showing the closely-packed manganese nodules. Photo credits: Nils Brenke, CeNak
The formation of nodules is a process that occurs at a slow pace and can last for millions of years. Small pieces of deep-sea bone, rock and fossils are covered with manganese hydroxide together with other metals like zinc, copper, iron and cobalt, that crystallise over and around them. Adding even one centimeter to the diameter of the nodule might take hundreds and hundreds of years. The nodules normally have an irregular shape and are flattened.
The recently discovered nodules are peculiar though since they deflect from the normal occurrences and are much rounder than expected. Furthermore, the size has caught the attention of the scientists even further. The nodules in the deposit were the size of a bowling ball, but some were much smaller.
Manganese nodules. Photo credits: Thomas Walter.
It is thought that the samples might be more than 10 million years old.
”Manganese nodules are found in all oceans. But the largest deposits are known to occur in the Pacific. Nodules of this size and density in the Atlantic are not known,” Devey explained.
Yet again, scientists have been confronted with one of the most compelling facts of life: the more we know, the more we understand that we know practically nothing.
A scientist from the University of Hamburg, Angelika Brandt, attested to it by making the following statement:
“This discovery shows us how little we know of the seabed of the abyssal ocean, and how many exciting discoveries are still waiting for us. At this station, very few organisms were found in the nets which captured the manganese nodules. It is quite possible that living creatures find the immediate vicinity of the nodules quite inhospitable. The second haul with the epibenthic sled at this station, which sampled over a continuous manganese crust with a thick layer of sediment on top, was quite different. Here the net collected many organisms which we were able to see with the naked eye, and we are already looking forward to the analysis of this sample.”
The manganese nodules will now be analysed. It is believed that they might shed light on the Earth of the past, including aspects like ocean conditions and climate.
“We will continue our planned program. But the samples obtained here will definitely be examined in detail in our land-based laboratories. We are now excited to see what surprises the Atlantic might still hold for us,” Devey concluded.