Interactive effects of temperature, ocean acidification, and pyrene on Calanus glacialis nauplii

Abstract

Climate change is increasing the earth’s temperature and acidifying its ocean. These changes are expected to be more severe in the Arctic region. Higher temperatures in the Arctic Ocean will reduce its sea ice and open it up for shipping and petroleum activity, which will expose the Arctic to polycyclic aromatic hydrocarbons (PAHs) such as pyrene. This study is a part of the Nansen legacy project, and aims to look at the effect of warming, ocean acidification, and pyrene on the nauplii of Calanus glacialis. Adult C. glacialis females were sampled from the Northern Barents Sea in March of 2021 and brought back to the University of Oslo for the experiments. The eggs from C. glacialis were placed in tubes in eight different combinations of Temperature, pH, and Pyrene concentrations. The tubes were checked every day for 1.5 months and the survival and development of the nauplii were noted. It was found that elevated temperatures decreased the development time to nauplii stage 3. Almost no nauplii developed to nauplii stage 3 in the pyrene exposed treatment at lower temperatures possibly due to the narcotic effect of pyrene. Mortality was highest in the pyrene exposed nauplii at the higher temperature. More nauplii reached nauplii 3 at higher temperatures with pyrene than at the lower temperatures. Due to methodological challenges, the effect of future OA could not be concluded. Other studies however point to the nauplii being tolerant to ocean acidification due to genetic expression. Interactive effects between higher temperatures and pyrene toxicity were found, indicating that C. glacialis will be exposed to higher PAH toxicity in a future warmer Arctic.