Meeting Abstract

P1-166  Thursday, Jan. 4 15:30 – 17:30  Combined effects of acidification and hypoxia on the estuarine ctenophore, Mnemiopsis leidyi MOSO, E/M; ENZOR, L/A*; HANKINS, C; BARRON, M/G; EPA; EPA; EPA; EPA moso.elizabeth@epa.gov

Estuaries are transitive zones which experience large fluctuations in environmental parameters (temperature, dissolved oxygen, pH, etc.). The interactive effects of reduced dissolved oxygen (DO) and elevated pCO₂ on estuarine organisms is not currently well understood. Ctenophores are an important factor in estuarine planktonic trophic pathways because they are voracious consumers of planktonic organisms. Ctenophores have shown a resistance to the negative effects of hypoxia, however, there is little information about their resistance to acidification and combined effects of hypoxia and acidification. This study determined acute sensitivity by measuring the survivability at two life stages of the ctenophore Mnemiopsis leidyi, larval (early cydippid) and adult (reproductive lobate). Over a 5-day test period ctenophores were exposed to four treatments: ambient, elevated pCO₂ (1300µatm, IPCC RCP 8.5 scenario), hypoxic (low dissolved oxygen, 2 mg/L), combined (elevated pCO₂ and hypoxic). Preliminary research suggests a sensitivity to elevated pCO₂ and combined treatments, and no effect in the hypoxic treatment.