Soil And Marine Life Hugely Destroyed Due To Offshore Mining
We all know that the ocean is rich in immense marine biodiversity, but that’s not all. It also offers a great diversity of minerals in its depths, which are already being mined. This type of work has a high cost and many risks. Currently, there is no commercial scale mining at sea and there is no specific technique for marine mining, points out Luigi Jovane, associate professor at USP’s Oceanographic Institute (IO).
“Some companies built some equipment and had a research project to study exploration techniques, but new machines are still being developed to optimize efficiency and minimize the impacts caused by plumes in sediment mobilization on the seabed, which are the greatest risks. Remotely operated underwater vehicles can be used to locate the main extraction and collection sites on the seabed,” he says. Companies, mostly Asian, Chinese and Japanese, are developing projects to collect polymetallic nodules with hydraulic pumps, a hose system that takes the extracted materials to vessels or platforms on the surface.
Volcanic mud, iron-manganese crusts, polymetallic nodules and polymetallic sulfide deposits can be exploited to extract e-tech elements, that is, critical and essential elements for modern technologies. Hydrothermal vents are rich in copper, gold, lead, silver and other precious metals. In addition, phosphorites, carbonaceous granules, lithothamnium and other types of seaweed are used for fertilizers, animal supplements, among many other uses.
According to Professor Jovane, these samples are transported for processing, which can be done directly on the ship or with more complex techniques in metallurgy stages. “There are several methods for each of these materials to collect. The machines that are fundamentally used are a type of dredger with a suction system, but there are also other types of techniques such as ultrasound, pneumatic hammers, which manage to disaggregate and fragment the rocks and then take them to the surface”. The plume component is very important because it can increase toxicity and generate a large amount of suspended material, which can be carried away by currents. This can change many physical and chemical characteristics of water over very long distances and can have impacts that are not known today.
Extraction does not use toxic materials directly for mining, but other jobs carry risks. The professor explains that, for the metallurgy part, the extraction of rare earths and metals from the crusts, from the nodules, a large amount of energy and chemical products that are highly toxic and polluting are required.
Impacts
There is a lack of studies on the environmental effects of long-term offshore mining. The most direct impacts on mining sites are the destruction of natural soil forms and marine life (micro and macrofauna), the compaction of the sea floor and the creation of sediment plumes that disturb aquatic life. Released material can travel great distances. It can leave, for example, the South Atlantic and reach Ireland, the North Sea in Europe and have a huge impact on the climate, fishing, on water conditions elsewhere in the world, because all the currents are interconnected. In addition, impacts also create noise, light, electromagnetic effects or interruption of larval supply, contamination and alteration of fluid flow.
Several environmental impacts on species can be detailed, such as the disturbance in ecological diversity. The more tolerant species will survive, while the less tolerant ones may become extinct. Disturbance in the supply of larvae will cause certain species to decline. Even more important: the habitat of benthic organisms (micro or macro) could be destroyed, as their substrate would be extracted. Hydrothermal vents contain thriving habitat unless careful studies and research are not carried out prior to mining.
The International Seabed Authority (ISA), an international organization established in accordance with the United Nations Convention on the Law of the Sea, decides to whom (country or company) and under what conditions the exploration contract should be awarded. The International Seabed Authority exploration license contracts are well explained and their aim is to study all aspects of deep sea mining, with a special focus on environmental impacts. So far, there are no exploration (commercial) contracts granted by ISA.