Abstract
High mineral demands drive a worldwide increase in mining activity. In Norway, mine tailing disposal in fjords is practiced at several locations, raising environmental concern due to the spreading of particulate matter in the water column and the potential release of metals and process chemicals. In this study, Calanus finmarchicus nauplii stage 6 were exposed to three different tailing types; pure calcium carbonate particles (Par), marble tailings (Marble) and copper mine tailings (Copper), in high (H; nominally 750 000 particles/mL) and low (L; nominally 37500 particles/mL) concentrations on rotating wheels for 15 days. At each sampling point (six in total) one bottle from each treatment were sampled. Analysed endpoints included stage determination, biometry and respiration. Copepods in all treatment groups reached copepodite stage 4 by the last sampling, but with a lower proportion of stage 4 present in the high treatments and ParL. Biometric measurements at the last sampling point revealed a significant difference in body length (H(7) = 49.63, p < 0.0001) and lipid sac area (H(7) = 54.39), p < 0.0001), where the body length of ParL and MarbleH, and the lipid sac area of ParL and CopperH differed significantly from Control. In addition, respiration rates differed significantly (F(6,21) = 11.96, p < 0.0001), with ParL, MarbleH and CopperH having significantly lower respiration rates compared to Control. Our results show that developing C. finmarchicus are affected by the presence of tailings, generally with higher suspension concentrations having a stronger impact, with copepods in the treatment groups having a lower body length, lipid sac area and respiration rate at the end of the study. The absence of a flocculation agent is the most likely reason for the marked response of ParL, causing particles to be present in the water column for a longer time.
