The effects of acidified seawater on the polychaete Nereis virens Sars, 1835

The ragworm Nereis virens was maintained in seawater over a pH range of 5.1–8.1 (control). At 18°C the worms were active and demonstrated deleterious effects at pH ≤6.5 within 10 days, shown by mortality, burrowing activity and dry weight; survivors below pH 6 showed significantly reduced glycogen levels, indicating that stored reserves were needed to maintain metabolism within this short period. At 9°C the worms were comparatively inactive, showing no significant mortalities over 30 days; again, body weight was significantly depressed below pH 6.5. Glycogen levels gave the clearest indication of stress, with a significant decline below pH 6.5. It is concluded that such low pH levels are deleterious to N. virens, and also that monitoring body glycogen levels gives a useful indication of stress over timescales where whole animal responses may be poorly indicative.