Research conducted showed that metal nodules have an important function in deep-sea ecosystem as they provide hard substrate for different organisms, such as stalked sponges. Removing these nodules leads to a loss of the fauna that is directly or indirectly dependent on them which can be 20% in the Peru Basin and in the Clarion-Clipperton Fracture Zone. However, nodule associated fauna has a very limited role in abyssal carbon cycling. Hence, depending on whether the impacts of deep-seabed mining on biodiversity or on carbon cycling are studied, research should either focus on fauna (biodiversity) or the microbial loop (carbon cycling)