- Author: GREAT MASTER VIKRANT ROHIN
- Date: MAY 3, 2023
Science may not be aware of up to two-thirds of the deep ocean species.
As a new era of deep sea mining is about to begin, a new study attempting to grasp this variety discovered that 60% of DNA sequences from marine sediments could not be classified at a higher taxonomic level. This finding highlights the enormous gap in scientific understanding.
Since so much of the richness of the deep bottom has yet to be uncovered by science, it may be up to three times as diverse as the waters above it.
According to a study that examined hundreds of sand samples collected during excursions across the world’s oceans, the deep sea’s variety remains unknown in over two-thirds of cases. Some of these entirely new life forms might be connected to the biological carbon pump, which serves to control the climate of the planet.
‘It’s been known since at least the 1960s that life is extraordinarily diverse on the ocean floor, and that the majority of species that are found in the deep sea are undescribed,’ says Dr. Andrew Gooday, co-author and scientific associate at the Museum. What is unusual about this study is that a sizable amount of this novel variety occurs at a higher taxonomic level, indicating that the deep sea is home to numerous undiscovered species of animals. Instead of the larger creatures that most studies concentrate on, the majority of these new lineages are likely to be small protozoans.
The possibility for seabed mining in some areas has spurred discussion about the potential effects on marine ecosystems, even though the majority of the deep bottom is still largely unexplored by humans. The study’s authors, who wrote about it in the journal Science Advances, hoped that it would strengthen the case for protection in this final unexplored area of Earth.
The Unexplored Ocean
In comparison to the land, the oceans are relatively understudied, with just 21% of the seafloor being mapped at high resolution. This is despite the oceans covering 71% of the Earth’s surface. As a result, a large portion of the life that inhabits it is unknown; according to one study, up to 91% of the species in the ocean have not yet been identified.
The vast immensity of the ocean is one of the major challenges in finding these species. At Challenger Deep, the deepest point of the ocean, marine species are distributed vertically from the surface to a depth of 11,000 metres, but terrestrial life is often restricted to the planet’s surface.
The challenges of studying the environment of the deep ocean, such as the high pressure, lack of light and the great depth, makes the discovery of species that live there even more difficult, particularly when they live beyond the sunlit and twilight zones of the water column.
This has also meant that the abyssal regions of the ocean, which are deeper, have remained mostly unaltered. This might not be the case for very long, though, given the presence of precious metal deposits on the ocean floor.
Deep sea mining proponents assert that these metals are necessary for the creation of environmentally friendly technology like electric vehicles and wind turbines, which need the materials to produce and store electricity.
Because of the increasing demand for these metals, their extraction from the seabed could assist to reduce shortages, greenhouse gas emissions, and the effects of terrestrial mining.
However, there may be catastrophic effects on marine life because of the lack of information about the ecosystems of the seabed. The sediment plumes produced by the mining could harm habitats, disrupt nutrient cycles, and deplete oxygen across larger areas in addition to the effects of the mining trucks themselves.
Deep sea mining should be prohibited or at the very least delayed until its effects are more well known, according to opponents.
Deep seabed mining will undoubtedly have some impact, at least locally, but Andrew thinks it’s currently difficult to predict how it will affect the richness of the deep sea. Many species are probably still undiscovered, while others may only have been discovered in a single sample.We are unsure if this is because they are uncommon but only found in limited locations, putting them at risk of extinction due to mining, or if they are common but only found in limited areas. The chance of extinction would be significantly lower in the latter scenario.
Commercial mining activities may not be too far away, even though they are now still in the exploration stage. The country of Nauru started a two-year countdown for the implementation in June 2021.
As such, the race is on for scientists to understand marine diversity before the impact of mining begins.
The Depth Of Diversity
The group of international researchers examined 418 sand samples from various depths and regions of oceans throughout the world to gauge the variety of oceanic life. Then, these were contrasted with tens of thousands of samples from the surrounding water that had been collected during earlier excursions.
Nearly two billion DNA sequences, divided into 240,000 sequence variants, were the result. As a result, they were able to compare the DNA of species that live on the seafloor for the first time with that of organisms that have dropped from the higher seas.
According to an analysis of the data, there are much more species of life in marine sediment than there are in the waters above. Nematode worms, along with amoebae, ciliates, foraminifera, and a variety of other single-celled creatures, dominated among the primary groupings that could be discovered at the seafloor.
Given our existing understanding of marine life, 60% of the deep sea DNA sequence variants could not be classified in any known higher-level grouping. The scientists hypothesised that the unidentified DNA might represent entire, unrecognised lineages of marine life.
It was discovered that some of these lineages are connected to the biological carbon pump, a natural cycle that moves a significant quantity of atmospheric carbon in the deep oceans. These organisms carry the carbon with them as they perish and descend to the ocean’s floor. This may be maintained in the deep marine sediment for all time or may ultimately resurface in the upper ocean.
According to Andrew, the study sheds fresh information on the transfer of carbon to the seafloor, which is crucial in the context of climate change because “some of the unknown taxa seem to be involved in this process.”
