Seawater warming intensifies nickel toxicity to a marine copepod: a multigenerational perspective

Due to human activities, marine organisms are frequently co-stressed with nickel (Ni) pollution and seawater warming; nevertheless, very scarce information is known about their interaction in marine biota under a multigenerational scenario. Here, after verifying the interaction of Ni and warming via a 48-h acute test, we conducted a multigenerational experiment (F0-F2), in which the marine copepod Tigriopus japonicus was exposed to Ni at environmentally realistic concentrations (0, 2, and 20 µg/L) under ambient (22℃) and predicted seawater warming (26℃) conditions. Ni accumulation and the important life history traits were analyzed for each generation. Results showed that Ni exposure caused Ni bioaccumulation and thus compromised the survivorship and egg production of T. japonicus. In particular, seawater warming significantly increased Ni accumulation, thus intensifying the negative effects of Ni on its survivorship and development. Overall, this study suggests that Ni multigenerational exposure even at environmentally realistic concentrations could produce a significant impact on marine copepod's health, and this impact would be intensified under the projected seawater warming, providing a mechanistic understanding of the interaction between warming and Ni pollution in marine organisms from a multigenerational perspective.