Deformities in larvae and juvenile European lobster ( Homarus gammarus ) exposed to lower pH at two different temperatures

• Published in: Biogeosciences
• Main Authors: A.-L. Agnalt, E. S. Grefsrud, E. Farestveit, M. Larsen, F. Keulder
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2013
• Subjects: Ecology; QH540-549.5; Life; QH501-531; Geology; QE1-996.5; European lobster; Homarus gammarus; Ocean acidification
• Online Access: https://doi.org/10.5194/bg-10-7883-2013; https://doaj.org/article/d55934b98feb43fa98971dabad565f46

The ongoing warming and acidification of the world's oceans are expected to influence the marine ecosystems, including benthic marine resources. Ocean acidification may especially have an impact on calcifying organisms, and the European lobster ( Homarus gammarus ) is among those species at risk. A project was initiated in 2011 aiming to investigate long-term effects of ocean acidification on the early life-cycle of lobster under two temperatures. Larvae were exposed to p CO 2 levels of ambient water (water intake at 90 m depth), medium 750 (pH = 7.79) and high 1200 μatm p CO 2 (pH = 7.62) at temperatures 10 and 18 °C. The water parameters in ambient water did not stay stable and were very low towards the end of the experiment in the larval phase at 10 °C,with pH between 7.83 and 7.90. At 18°, pH in ambient treatment was even lower, between 7.76 and 7.83, i.e. close to medium p CO 2 treatment. Long-term exposure lasted 5 months. At 18 °C the development from stage 1 to 4 lasted 14 to 16 days, as predicted under optimal water conditions. Growth was very slow at 10 °C and resulted in three larvae reaching stage 4 in high p CO 2 treatment only. There were no clear effects of p CO 2 treatment, on either carapace length or dry weight. However, deformities were observed in both larvae and juveniles. The proportion of larvae with deformities increased with increasing p CO 2 exposure, independent of temperature. In the medium treatment about 23% were deformed, and in the high treatment about 43% were deformed. None of the larvae exposed to water of pH >7.9 developed deformities. Curled carapace was the most common deformity found in larvae raised in medium p CO 2 treatment, irrespective of temperature, but damages in the tail fan occurred in addition to a bent rostrum. Curled carapace was the only deformity found in high p CO 2 treatment at both temperatures. Occurrence of deformities after five months of exposure was 33 and 44% in juveniles raised in ambient and low p CO 2 levels, respectively, and 21% in juveniles ...