Taucher J, Lechtenbörger AK, Bouquet JM, Spisla C, Boxhammer T, Minutolo F, Bach LT, Lohbeck KT, Sswat M, Dörner I, Ismar-Rebitz SMH, Thompson EM, Riebesell U.

The appendicularian Oikopleura dioica can enhance carbon export in a high CO2 ocean.

Glob Chang Biol. 2023 Nov 10:e17020. doi: 10.1111/gcb.17020.

“pelagic mesocosms [...], each extending to a depth of 21 m (19 m cylindrical bag and 2 m full size/diameter conical sediment trap attached to the bottom of the bag) and enclosing about 60 m3 of the natural water column.” “Average pCO2 during the experiment ranged between ~320 (“ambient”) and 1700 μatm (“high CO2,” corresponding to a drop in pH by 0.57 units compared to ambient conditions).” “a custom-built net (50 μm mesh size; 20 cm in diameter) with a modified, non-filtering cod end (3.8 L clear polycarbonate beaker) and reduced towing speeds (0.15 m s−1) was applied in order to collect alive and undamaged O. dioica specimen.” “The peak biomass of O. dioica was approximately twice as high in the high CO2 mesocosms (2.5 vs. 1.3 μgC L−1) and occurred earlier (days 13–17) than under ambient conditions (day 21)”. “female O. dioica were cultured in mesocosm water (pre-filtered through a 50-μm mesh) of the respective CO2 conditions until they achieved maturity and produced eggs.” “The fecundity of O. dioica was significantly elevated under lower pH, with females producing 278 (±107) eggs under ambient and 334 (±14) eggs in the OA treatment“