Genetic toxicology of zooplankton in a changing marine environment

Abstract

Understanding organism responses to pollutants and environment stressors is important in light of climate change shifting regimes of temperature, pH, and spread of contaminants at rates previously not experienced in stable marine environments. Organisms el icit responses in the form of detoxification, stress response mechanisms, and damage repair processes. Impacts and damage at the genetic level can underpin higher level effects in physiology, behaviour, survival, and transgenerational impacts, which can dr ive population and species level changes. Species can vary in their sensitivity to genetic stress as well as their capacity to respond and adapt. Comparative experiments with Acartia longiremis and Calanus spp. provide insight into sensitivity and resilien ce of Arctic zooplankton populations. Water conditions simulating predicted Arctic ocean acidification cause genotoxicological impacts in A. longiremis in the form of DNA strand breaks, with indications that older life stages are more susceptible to genoto xic impacts compared with individuals collected from earlier in the summer season. Genetic damage was also detected in Calanus spp. exposed to multistressor conditions of ocean acidification and warming, and A. longiremis exposed to combined temperature and copper conditions, and A. longiremis is more resilient to DNA damage compared with Calanus spp. Ongoing gene expression analyses will investigate the comparative capacity for DNA repair between the two species, and develop tools for transcriptional biomarkers of oxidative stress to determine the molecular mechanisms driving adverse effects and mortality. Arctic genetic ecotoxicology of zooplankton can inform on wider ecosystem vulnerability to future climate and pollution conditions.