Macrofaunal colonization of mine tailings impacted sediments

Area of Science:

• Marine Biology
• Environmental Science
• Ecotoxicology

Background:

• Marine mine tailings disposal can impact benthic ecosystems.
• Understanding macrofaunal colonization is key to assessing ecosystem recovery.
• Previous studies have not systematically compared colonization across different tailings types.

Purpose of the Study:

• To compare macrofaunal colonization of thin mine tailings layers on marine sediments.
• To evaluate the effects of different Norwegian mine tailings on benthic communities.
• To assess the influence of tailings characteristics, including chemical content, on colonization.

Main Methods:

• Experimental boxes with marine sediments capped with mine tailings were deployed on the seabed.
• Colonization was monitored over six and twelve months.
• Three types of Norwegian mine tailings and a control (no tailings) were used.

Main Results:

• Fine-grained tailings with flotation chemicals exhibited significantly lower macrofaunal colonization.
• All treatments, including tailings, supported species-rich communities.
• Annelid abundance generally decreased, while mollusk abundance increased in tailings treatments compared to controls.
• Differences in faunal density between control and tailings treatments were more pronounced at six months than twelve months.

Conclusions:

• Mine tailings affect benthic macrofaunal colonization, with variations based on tailings composition.
• The findings have implications for the management of marine tailings and understanding recovery from seabed disturbances.
• This study provides a systematic comparison of tailings colonization potential, informing ecological risk assessments.