Candidate indicators for NORI-D

Report: DPSIR Components and Candidate Indicators for Polymetallic Nodule Mining within the NORI-D Lease of the Clarion-Clipperton Zone

• A set of ecosystem indicators was developed to monitor the environmental impacts of deep-sea mining in the NORI-D lease area.
• The DPSIR framework (Driver-Pressure-State-Impact-Response) was used to link mining activities to ecosystem changes and guide management responses.
• The study identified 13 pelagic and 18 benthic indicators under worst-case scenarios, and 3 pelagic and 17 benthic indicators under Project Zero scenarios.

This report outlines a science-based approach to identifying environmental indicators for monitoring the impacts of deep-sea mining in the Clarion Clipperton Zone (CCZ), focusing on the NORI-D lease area. The work was led by CSIRO and its research partners, using the DPSIR framework to connect mining activities to environmental pressures, potential changes in ecosystem state, and potential impacts to ecosystem values, functions and services, while also evaluating effectiveness of management responses.

To build the framework, experts in deep-sea ecology were selected through a global literature review and invited to workshops in London, UK, and Long Beach, USA. These experts helped construct qualitative mathematical models – called signed digraphs – for both pelagic (open water) and benthic (abyssal seafloor) ecosystems. These models mapped out how different species and ecosystem processes interact, and how they might respond to mining-related pressures.

The models were tested and validated using known ecological patterns, such as how light affects phytoplankton with depth. Two types of scenarios were then assessed:

• Worst-case scenarios, where all potential mining and non-mining pressures were applied.
• Project Zero scenarios, which included only those pressures The Metals Company believes can’t be avoided or mitigated.

The models predicted how different parts of the ecosystem would respond to these pressures. From this, the team identified candidate indicators – species or ecosystem features that show clear, predictable responses to mining impacts. These indicators are essential for monitoring and managing environmental change.

In the worst-case scenarios, 13 environmental indicators were identified for the pelagic system and 18 for the benthic system. Under the Project Zero scenario, fewer pelagic environmental indicators (3) were identified due to greater uncertainty, but 17 benthic indicators were still found to be useful.

This work provides a foundation for evidence-based environmental monitoring and informs the development of responsible deep-sea mining should commercial-scale operations commence.