South China Sea Mining Trial Coincides With Shifts in Microbial Nutrient-Cycling Genes

Comparing water and DNA before and during mining

According to the reported study, cobalt-rich rocks were retrieved during a mining trial about 1,300 meters below sea level. Researchers collected water before and during mining, as well as DNA samples from rocks and water, and found changes in nutrient-related microbial gene signals during the activity.

The reported study compares samples collected before mining with samples collected during a 2020 trial, but does not specify the interval between those collections.

During mining, water samples showed lower abundances of genes associated with nitrogen fixation and nitrite reduction, while genes associated with denitrification and dissimilatory sulfate reduction increased in the reported samples.

Observations limited to one trial’s conditions

The observations connect a single deep-sea mining trial to measurable changes in microbial processes that transform nutrients near the seafloor. They are limited to the sampled conditions of that trial and do not establish the timing of the changes or longer-term effects.