Impacts of an industrial deep-sea mining trial on macrofaunal biodiversity

Eva C D Stewart ^1,2, Helena Wiklund ^3,4,5, Lenka Neal ³

⁰Natural History Museum, London, UK. e.stewart@nhm.ac.uk.

Nature Ecology & Evolution +

|

December 5, 2025

View abstract on PubMed

Summary

Deep-sea mining significantly reduced macrofaunal density and species richness in mining tracks. Sediment plumes altered species dominance, impacting overall biodiversity in the abyssal plain.

Area Of Science

Marine Biology
Deep-Sea Ecology
Environmental Science

Background

Deep-sea mining is a developing industry with potential environmental impacts.
Understanding the effects of polymetallic nodule extraction on abyssal fauna is crucial.

Purpose Of The Study

To assess the spatio-temporal variation in macrofaunal abundance and biodiversity following deep-sea mining tests.
To differentiate direct mining impacts from natural environmental variability.

Main Methods

Quantitative species-level analysis of sediment-dwelling macrofauna.
Comparison of data from 2 years pre-mining and 2 months post-mining.
Investigation of areas directly mined and affected by sediment plumes.

Main Results

Macrofaunal density decreased by 37% and species richness by 32% within mining tracks.
Community multivariate dispersion significantly increased in mined areas.
Sediment plumes altered species dominance but did not affect faunal abundance.

Conclusions

Deep-sea mining causes significant local biodiversity loss, particularly in mining tracks.
Species-level taxonomic data is vital for assessing biodiversity risks.
Effective baseline and impact surveys are essential for managing deep-sea mining.