Ingestion rate and egg production of copepods collected in the upper 100m in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The phytoplankton dataset is based on samples taken during March-April 2008 in Libyan Sea, Southern Aegean Sea and Northern Aegean Sea. Ingestion rates were estimated from experiments performed at all the third priority stations during the cruise according to DoW of Sesame project. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 100 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Calanus helgolandicus and Centropages typicus according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs/female/day) collected in the 0-100m layer. Copepod egg production was measured for the copepods Eucalanus monachus, Centropages typicus and Calanus helgolandicus. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mg/m**2/day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Seawater carbonate chemistry, survival rate, shell size, calcification rate of the planktonic foraminifer Neogloboquadrina pachyderma (sinistral) in a laboratory experiment

The present study investigated the effects of ocean acidification and temperature increase on Neogloboquadrina pachyderma (sinistral), the dominant planktonic foraminifer in the Arctic Ocean. Due to the naturally low concentration of [CO3] 2- in the Arctic, this foraminifer could be particularly sensitive to the forecast changes in seawater carbonate chemistry. To assess potential responses to ocean acidification and climate change, perturbation experiments were performed on juvenile and adult specimens by manipulating seawater to mimic the present-day carbon dioxide level and a future ocean acidification scenario (end of the century) under controlled (in situ) and elevated temperatures (1 and 4 °C, respectively). Foraminifera mortality was unaffected under all the different experiment treatments. Under low pH, N. pachyderma (s) shell net calcification rates decreased. This decrease was higher (30 %) in the juvenile specimens than decrease observed in the adults (21 %) ones. However, decrease in net calcification was moderated when both, pH decreased and temperature increased simultaneously. When only temperature increased, a net calcification rate for both life stages was not affected. These results show that forecast changes in seawater chemistry would impact calcite production in N. pachyderma (s), possibly leading to a reduction of calcite flux contribution and consequently a decrease in biologic pump efficiency.