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Ecological Aspects of Deep-Sea Mining

The Joint Action Ecological Aspects of Deep-Sea Mining assessed the long-term impacts of polymetallic nodule mining on the deep-sea environment.


The Joint Action gathered 32 partners from 10 different countries. They conducted an independent scientific monitoring of the impact of an industrial test to harvest manganese nodules in the Clarion Clipperton Zone.




  • Concluded



€ 22,900,000


Feb 2013 - Aug 2022

Type of action

Joint Call

Lead country


Participating countries


The Joint Action gathered 32 partners from 10 different countries. They conducted an independent scientific monitoring of the impact of an industrial test to harvest manganese nodules in the Clarion Clipperton Zone. 

Since 2018, the MiningImpact 2 project followed up on the results of the first JPI Oceans supported MiningImpact project (2015-2017). While the initial project investigated experimental and rather small disturbances of the seafloor over decadal timescales, the new project conducted a comprehensive monitoring programme to ensure an independent scientific investigation of the environmental impacts of a manganese nodule collector system by the Belgian company Global Sea Mineral Resources (DEME-GSR). 

The fieldwork of the MiningImpact 2 project consisted of two research cruises. The first expedition took place in 2019 on the German research vessel RV SONNE, during which environmental baseline data were collected in the Clarion-Clipperton Fracture Zone (CCZ) in the Northeast Pacific. Initially, the environmental studies in 2019 were planned to take place in parallel to a manganese nodule collector trial. That trial was, however, postponed due to a technical failure of the collector system. In the spring of 2021, MiningImpact 2 finally conducted the independent scientific monitoring of DEME-GSR’s first industrial nodule collector test.


MiningImpact 2 aimed to close existing knowledge gaps and reduce uncertainties on the environmental impacts of deep-sea mining of polymetallic nodules. The project specifically worked towards policy recommendations and includes the International Seabed Authority as a partner. It further contributed to the preparation of environmental impact assessments (EIAs) for future European deep-sea pilot mining tests that are requested by the ISA and to the Horizon2020 technology development projects Blue Atlantis and Blue Nodules.


In general, the cost-effective joint use of research infrastructure facilitates the development of a common understanding and integration of national research activities around a common scientific objective. The collaborative approach has also enabled more effective collective European contributions to international policy-making.

Both MiningImpact projects delivered input into the development of the international Mining Code, a set of regulations for the exploitation of polymetallic nodules in the deep seabed beyond the limits of national jurisdiction, which the International Seabed Authority (ISA) is in the process of negotiating. In 2016, MiningImpact presented these results at an ISA meeting in order to ensure that the international deep sea mining regime builds on the best available scientific knowledge.

The scientific findings of the first project were:

  • Nodule ecosystems support a highly diverse fauna of sessile and mobile species.
  • Faunal communities & environmental parameters show a high variability even on a very local spatial scale.
  • Benthic fauna communities differ significantly between seamounts and nodule habitats.
  • Loss of seafloor integrity by nodule and sediment removal generally reduces population densities and ecosystem functions.
  • Biogeochemical remineralization processes and the productivity of the benthic community are both impacted by nodule removal.
  • Disturbance impacts on nodule ecosystems last for many decades, affect numerous ecosystem compartments and functions

 More details can be found in a booklet describing the final results of the project.

Why is this important?

The last decade has seen a steady increase of interest in deep-sea mining to secure mankind’s future demands in raw materials. Several European countries, i.e. Belgium, France, Germany, United Kingdom, Russia, and a consortium of former Soviet Union countries, have registered claims with the International Seabed Authority to explore mineral resources in the abyss. The ISA is currently developing its international regulatory framework governing the exploitation of mineral seabed resources in areas beyond national jurisdiction, the “Mining Code”.

With deep-sea mining inevitably causing disturbances to abyssal ecosystems, because mineral deposits in focus cover extended areas of the inhabited seafloor that will be disturbed directly and indirectly by mining operations, it is important that international legislation is based on the best available knowledge. JPI Oceans aimed to contribute to the development of the Mining Code by filling knowledge gaps in the field.