Fig. 1: Overview of the sampling area in the Drake Passage and the Western Antarctic Peninsula.

Twenty-two in situ stations were sampled during the Polarstern expeditions PS97 (red dots), including BIO1 as station West and BIO3 as station East, as well as during PS112 (yellow dots). For station West and East, initial concentrations of dissolved iron (dFe), dissolved manganese (dMn), chlorophyll a (Chla) as well as the 1h-dark-adapted maximum photosystem II quantum yield (Fv/Fm) are shown in the dark box.