MEPS 579:67-79 (2017)  -  DOI: https://doi.org/10.3354/meps12275

ABSTRACT: Exposure to environmental stressors such as pollutants early in life may have latent effects visible only in later life stages. Sea urchin Evechinus chloroticus larvae were exposed briefly (2 d) to 4 treatments of low levels of copper (2 to 10 µg l^-1). Juveniles were re-exposed to a further short pulse of copper (10 µg l^-1) to investigate potential resistance to pollution. No major direct effects of larval exposure to copper were observed on larval growth, survival or settlement success. However, complex latent effects started to appear from 8 d post-settlement onwards in individuals exposed as larvae to the highest concentration of copper. Juveniles had strongly impaired growth from 8 to 25 d post-settlement, with average radial length and spine to body ratio decreasing by 24% for both variables. In addition, juveniles previously exposed to the highest tested concentration of copper as larvae were more vulnerable to a subsequent pulse, with up to 4 times higher mortality in groups previously exposed to copper during the larval stage. On the other hand, survivors had a 35% higher growth rate than naive juveniles (i.e. no previous exposure). These results demonstrate that exposure to a concentration of copper similar to that found in many polluted bays and harbours (10 µg l^-1) for as little as 48 h in early life impacts juvenile performance and leaves them more vulnerable to a subsequent exposure. This highlights the importance of considering latent effects when evaluating the impacts of pollution.

KEY WORDS: Latent effects · Copper toxicity · Sea urchin · Early life stages · Evechinus chloroticus