Physiological and ecological responses and changes of Phaeodactylum tricornutum under long-term stress of naphthalene

Abstract

Naphthalene, as a common polycyclic aromatic hydrocarbon (PAHs), attracts broad attention due to its toxicity to human and marine organisms. This study investigate the effects of naphthalene on growth, maximum photochemical efficiency (Fv/Fm), total esterase activity and reactive oxygen species production of Phaeodactylum tricornutum. The study explored how algal physiological characteristics change under naphthalene’s long-term exposure and analyzed the correlation between photosynthetic efficiency with growth, total esterase activity and reactive oxygen species production, respectively. The study shows that low-concentration naphthalene promotes slightly or doesn’t affect algal growth, total esterase activity and reactive oxygen species while it promotes Fv/Fm significantly. On the other hand, high-concentration naphthalene inhibits algal growth, total esterase activity and Fv/Fm significantly, while it stimulates reactive oxygen species production and the stimulation increases with time. The study also shows that growth and Fv/Fm of P. tricornutum are correlative and the correlation is related with naphthalene concentration. Fv/Fm of P. tricornutum is significantly positively-related with total esterase activity, while is significantly negatively-related with reactive oxygen species.