The effects of nickel on the reproductive ability of three different marine copepods

Lethal and sublethal toxicity of Nickel (Ni) to three marine copepods Tigriopus japonicus, Apocyclops borneoensis and Acartia pacifica was investigated. The 48-h LC50 values were 17.70, 13.05 and 2.36 mg l(-1) Ni, respectively. A. pacifica was found to be the most sensitive to Ni in acute exposure tests. In order to assess sublethal effects of Ni on copepod reproduction, the test organisms were exposed to four nominal Ni concentrations 0, 10, 100, 1000 mu g l(-1) Ni. The results indicated that offspring production of T. japonicus and A. borneoensis was significantly reduced after exposure to 10 mu g l(-1) Ni. Whereas egg production and egg hatching success of A. pacifica were significantly reduced at 100 and 10 mu g l(-1) Ni, respectively. Exposure of copepods to the highest Ni concentration caused a severely reduced nauplii production from T. japonicus, A. borneoensis and A. pacifica by 87.8, 56.9 and 65.8%, respectively, and a significantly reduced egg production of A. pacifica by 74.4%. These results show that Ni excess in the coastal environment can have detrimental effects on reproduction of copepods.