General Comments

• Main Author: V. Schoemann
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Southern Ocean
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.518.4955; http://www.cosis.net/copernicus/EGU/bgd/6/S1179/bgd-6-S1179_p.pdf?PHPSESSID=5b6c49c724f2f2b30175e68391760c6d

This laboratory study examines the influence of organic ligands on iron (Fe) solubility and Fe bioavailability to Southern Ocean phytoplankton isolates. In general, the ex-periments are well conceived and executed. In particular, the experiments examining polysaccharide ligands as Fe sources are novel and merit publication. Similarly, the experiments examining the effects of these ’model ’ ligands on Fe solubility are poten-tially of great interest and relevance. However, I have a number of serious concerns regarding the design and interpretation of the short-term Fe and C uptake experiments, which I detail below. Provided these concerns are addressed I think this paper merits S1179 publication as it will provide new insights into the processes governing Fe speciation and bioavailability. Specific Comments I have a number of questions regarding the design and interpretation of the Fe and C uptake experiments. I’ve particular concern with the author’s use of short-term Fe and C uptake rates to infer the degree of Fe-limitation and/or Fe requirements of the strains