Effects of the increase of temperature and CO2 concentration on polychaetae Nereis diversicolor: simulating extreme scenarios of climate change in marine sediments

In order to evaluate the effects of elevated temperature and pCO₂ on the polychaete Nereis diversicolor from the Río San Pedro estuary in Spain, multifactorial stressor experiments were performed in various combinations: at two temperatures (ambient temperature and temperature estimated for the year 2100) and at three pHNBS levels (estimated level in cases of CO₂ leakage, at the level used in the high and moderate CO₂ treatment, and present-day ambient pH levels). Experimental temperature treatments were designed within the context of a high-emission CO₂, “business as usual” scenario, with an approximate median increase in temperature of 3.7–4.8°C by the year 2100. In this study, it was investigated whether oxidative stress occurs in cellular responses to elevated temperatures and CO₂ levels in N. diversicolor. It was measured the levels of oxidative stress biomarkers, of hemoglobin, and of the carbonate system. The effects of ocean acidification on these organisms are almost unknown. This study has shown that when subject to pH and temperature stress, the Nereidid polychaete N. diversicolor exhibits reduced survival rates. Also the biomarker (Lipid Peroxidation—LPO) was also found to be sensitive to the pH versus temperature relationship.