Simulated future conditions of ocean warming and acidification disrupt the microbiome of the calcifying foraminifera Marginopora vertebralis across life stages

Foraminifera host diverse microbial communities that can shift in response to changing environmental conditions. To characterize climate change impacts on the foraminifera microbiome across life stages, we exposed adult\ua0Marginopora vertebralis\ua0(Large Benthic Foraminifera) to\ua0pCO2\ua0and temperature scenarios representing present day, 2050 and 2100 levels and raised juveniles under present day and 2050 conditions. While treatment condition had no significant effect on the seawater microbial communities, exposure to future scenarios significantly altered both adult and juvenile microbiomes. In adults, divergence between present day and 2050 or 2100 conditions was primarily driven by a reduced relative abundance of Oxyphotobacteria under elevated temperature and\ua0pCO2. In juveniles, the microbial shift predominantly resulted from changes in the proportion of Proteobacteria. Indicator species analysis identified numerous treatment‐specific indicator taxa, most of which were indicative of present day conditions. Oxyphotobacteria, previously reported as putative symbionts of foraminifera, were indicative of present day and 2050 conditions in adults, but of present day conditions only in juveniles. Overall, we show that the sensitivity of the\ua0M. vertebralis\ua0microbiome to climate change scenarios extends to both life stages and primarily correlates with declines in Oxyphotobacteria and shifts in Proteobacteria under elevated temperature and\ua0pCO2

Effects of chlorpyrifos on cholinesterase activity and stress markers in the tropical reef fish Acanthochromis polyacanthus

Tropical coastal ecosystems, including the Great Barrier Reef (GBR) of Australia are increasingly threatened by pollution; yet few studies have investigated the sensitivity of GBR species to these pollutants. Here we exposed juveniles of the tropical reef fish Acanthochromis polyacanthus (spiny damselfish) to three concentrations of the insecticide chlorpyrifos (CPF) and measured (i) muscle cholinesterase (ChE) activity; (ii) hepatic glutathione-S-transferase (GST) activity; and (iii) coenzyme Q (CoQ) redox balance, after 6 h and 96 h of exposure. After 96 h, muscle ChE activity was significantly inhibited by 26%, 49% and 53% when fish were exposed to 1, 10 or 100 μg/L CPF, respectively. Muscle ChE characterization revealed three types of ChEs, including two atypical forms. Hepatic CoQ antioxidant form significantly increased at 10 μg/L after 6 h of exposure, potentially demonstrating an early response to CPF-induced oxidative stress in liver. Hepatic GST was not affected by CPF exposure