Seawater carbonate chemistry and shell length of Mediterranean pteropod Cavolinia inflexa larvae during experiments

Larvae of the Mediterranean pteropod Cavolinia inflexa were maintained at controlled pHT values of 8.1, 7.82 and 7.51, equivalent respectively to pCO2 levels of 380, 857 and 1713 µatm. At pHT 7.82 larvae exhibited malformations and lower shell growth, compared to the control condition. At pHT 7.51 the larvae did not make shells but were viable and showed a normal development. However, smaller shells or no shells will have both ecological (food web) and biogeochemical (export of carbon and carbonate) consequences. These results confirm that 1pteropods, as well as the species dependent upon them as a food resource, will be severely impacted by ocean acidification.

Prosome length as well as carbon and nitrogen content of Calanus finmarchicus from the North Atlantic collected during Maria S. Merian cruise MSM26 in spring 2013

The prosome length of copepods from each station was measured on board with a dissecting microscope equipped with an ocular micrometer. Individuals were placed in pre-weighed tin caps and dried for 48 h at 60°C on board. Dry samples were transferred to the AWI and weighed again. Copepod dry mass was then calculated as the difference between the empty weight and the weight of the tin cap containing one individual. The content of carbon (C) and nitrogen (N) then was analysed with a CN-analyser (EuroEA Element Analyser, Hekatech) with acetanilide as standard.