Linking Rising pCO2 and Temperature to the Larval Development, Physiology and Gene Expression of the American Lobster (Homarus americanus)

• Main Author: Waller, Jesica
• Format: Text
• Language: unknown
• Published: DigitalCommons@UMaine 2016
• Subjects: Lobster; Ocean acidification; climate change; Marine Biology; Canada; Northwest Atlantic
• Online Access: https://digitalcommons.library.umaine.edu/etd/2527; https://digitalcommons.library.umaine.edu/context/etd/article/3587/viewcontent/M_JWaller_final.pdf

Anthropogenic warming and ocean acidification are occurring as CO2 continues to accumulate in the atmosphere (OA). Few studies have evaluated the joint effects of elevated temperature and partial pressure of CO2 (pCO2)on marine organisms. In this study we investigated the interactive effects of Intergovernmental Panel on Climate Change (IPCC) predicted temperature and pCO2 for the end of the 21st century on key aspects of larval development of the American lobster, Homarus americanus, an otherwise well-studied, iconic, and commercially prominent species in the northeastern United States and Atlantic Canada. Our experiments showed that larvae (stages I-III) and postlarvae (stage IV) reared at the temperature projected for the Northwest Atlantic by the year 2100 (19 °C) experienced significantly lower survival, developed twice as fast, and had significantly higher oxygen consumption rates, than those in 16 °treatments. Larvae from the high pCO2 (750 ppm) treatment at 16 °C had significantly longer carapace lengths, and greater dry masses in stages I-III and C: N ratios in the postlarval stage than postlarvae from all other treatments. Postlarvae raised in the high pCO2 treatment at 19 °C had significantly higher feeding rates and swimming speeds compared to postlarvae from the other three treatments. Together these results suggest that projected end-century warming will have greater adverse effects than increased pCO2 on larval survival, however the interactive effects of increased temperature and pCO2 have an additive impact on larval metabolism and behavior. To complement and expand upon our suite of results, we examined gene expression in postlarvae raised in each of the two pCO2 treatments at 16 °C. We selected 13 annotated genes of interest (GOIs) that were differentially expressed between postlarvae from the two pCO2 treatments. We found 11 GOIs related to cuticle formation that were significantly downregulated in postlarvae from the high pCO2 treatment, and two GOIs related to metabolism and stress response ...