Acute and chronic effects of polymetallic nodule leachate in the marine copepod Tigriopus japonicus

Abstract

Seafloor mineral resources has attracted the attention from around world due to increased demand for metals and resource depletion. Polymetallic nodules, one of metal resources from ocean, is contains primarily manganese and iron and other metals. However, leachate from polymetallic nodules would be discharged into oceans during mining process. It could cause problems in the marine ecosystem and have adverse effects on marine organisms. Thus, we investigated the acute and chronic effects of polymetallic nodules leachate extracted for 5 days and 10 days on life cycle parameters (e.g., mortality, development, and fecundity) in the marine copepod Tigriopus japonicus. Also, we investigated single and complex metals effects for Mn, Fe, Pb, Nd, Cu and Co that have difference in concentration between two types of leachates. There was no significant change in mortality but the developmental time and fecundity were significantly increased in response to leachate in T. japonicus, respectively. Compared results of two leachate, the effect of the leachate extracted for 10 days were lower than another. Suggesting that Nd has adverse effects on development and fecundity in T. japonicus and it could cause difference between two leachates. In this study, we could not find adverse effect for leachate from polymetallic nodule but extraction time of leachate will be considered when developing mining process to minimize effects on marine organisms.