Response of the ubiquitous pelagic diatom Fragilariopsis doliolus to manganese nodule exposure

Abstract

Increasing in metal demand and rising in its commodity prices have aroused a shift of exploration and development expenditure to the marine mineral resources from deep seabed. Before starting the mining from deep seabed, the biological impact of tailing disposal of mineral should be evaluated for sustainable development of the marine environment. Diatoms are a good indicator of aquatic quality due to their sensitivity to pollutants. Most of ecotoxicity tests using diatom, however have been conducted to the fresh water or coasts, there was no candidate diatom for ecotoxicity test in the ocean environment. The primary objective of this study was to evaluate the effect of manganese nodule on the pelagic diatom Fragilariopsis doliolus. We tested the effects of the particles of manganese nodule and its leachate on the growth of the diatom. All cultures were able to survive in the presence of particle of manganese nodule and its leachate. The growth rate of diatom did not effect in exposure of the leachate, but it was inhibited with increasing of the particle concentration (96h EC50=0.35 g L-1). Although we only based on the growth rate of the diatom, F. doliolus may be a suitable organism to assess the effects of toxicity in ocean in situ bioassay because the diatom is ubiquity and suitability for use under laboratory conditions. In future works, the other endpoints such as gene expression and deformity of diatom will be