Copepod vital rates under CO2-induced acidification: a calanoid species and a cyclopoid species under short-term exposures

11 pages, 3 figures, 2 tablesAlthough copepods have been considered tolerant against the direct influence of the ocean acidification (OA) projected for the end of the century, some recent studies have challenged this view. Here, we have examined the direct impact of short-term exposure to a pCO2/pH level relevant for the year 2100 (pHNBS, control: 8.18, low pH: 7.78), on the physiological performance of two representative marine copepods: the calanoid Acartia grani and the cyclopoid Oithona davisae. Adults of both species, from laboratory cultures, were preconditioned for four consecutive days in algal suspensions (Akashiwo sanguinea) prepared with filtered sea water pre-adjusted to the targeted pH values via CO2 bubbling. We measured the feeding and respiratory activity and reproductive output of those pre-conditioned females. The largely unaffected fatty acid composition of the prey offered between OA treatments and controls supports the absence in the study of indirect OA effects (i.e. changes of food nutritional quality). Our results show no direct effect of acidification on the vital rates examined in either copepod species. Our findings are compared with results from previous short-and long-term manipulative experiments on other copepod species. © 2015 The AuthorThis work was supported by the project CROA (LS8-1893), implemented within the framework of the Action «Supporting Postdoctoral Researchers» of the Operational Program “Education and Lifelong Learning” (Action’s Beneficiary: General Secretariat for Research and Technology), co-financed by the European Social Fund (ESF) and the Greek State. The participation of ES and CP was supported with funding by the Spanish Ministry of Economy and Competitivity through projects CTM2011-23480 and CTM2012-32017, respectivelyPeer Reviewe