Reduced pH increases mortality and genotoxicity in an Arctic coastal copepod, Acartia longiremis

Highlights: • The fast micromethod for DNA damage analysis was modified for use on copepods. • Lowered seawater pH causes elevated mortality in Acartia longiremis. • DNA damage in A. longiremis was elevated after long-term exposure to lowered pH. This study investigates DNA damage and mortality in an Arctic marine copepod after long-term exposure to lowered pH. Acartia longiremis were collected from northern Norway and incubated in ambient pH 8.1, and reduced pH 7.6 and 7.2 over 3-4 weeks. Cumulative mortality was significantly elevated in the lowered pH treatments in all exposures. The fluorescence-based fast micromethod for analysis of DNA strand breaks and alkali-labile sites was modified for use on crustaceous zooplankton. DNA damage initially increased in the lowered pH treatments, decreasing after >14 days, and DNA damage was significantly higher in lowered pH conditions. This method is ideal for investigating oxidative stress and genotoxicity response to low pH in Arctic marine copepods exposed to future ocean acidification conditions.