Aggregates feeding and pellet production from Microsetella norvegica collected during METEOR cruise M87/1 in Aril 2012

Harpacticoid Microsetella norvegica was fed with 5 concentrations of aggregates, collected from the station 1 (experiment 1) or from station 2 (experiment 2). The aggregates at station 1 were of phytoplankton origin and consisted mainly of Phaeocystis sp. and radiolarians; aggregates at station 2 were detritus collected from deep Mocness tows. M. norvegica was starved in filtered sea water for > 12 h, after which it was incubated together with aggregates for 8 h. After the incubation, pellets were counted and Microsetella and remaining aggregates were counted and measured. Pellet production of M. norvegica reflects feeding so that when pellet production is plotted against aggregate concentration, a functional response can be obtained.

Effects of feeding and light intensity on the response of the coral Porites rus to ocean acidification

Recently, it has been suggested that there are conditions under which some coral species appear to be resistant to the effects of ocean acidification. To test if such resistance can be explained by environmental factors such as light and food availability, the present study investigated the effect of 3 feeding regimes crossed with 2 light levels on the response of the coral Porites rus to 2 levels of pCO2 at 28 °C. After 1, 2, and 3 weeks of incubation under experimental conditions, none of the factors-including pCO2-significantly affected area-normalized calcification and biomass-normalized calcification. Biomass also was unaffected during the first 2 weeks, but after 3 weeks, corals that were fed had more biomass per unit area than starved corals. These results suggest that P. rus is resistant to short-term exposure to high pCO2, regardless of food availability and light intensity. P. rus might therefore represent a model system for exploring the genetic basis of tolerance to OA.