Kunert et al., Biogeoschiences, 2019, reviewer comments

Abstract

General comments The authors report on the ice nucleating ability of 112 strains from 65 different Fusarium species. Using standard, valid and well characterized drop freezing assays TINA and LINDA, the authors determined that 18/112 of the tests strains showed initial freezing temperatures of-3.5 to-11.2 oC and that 7/65 species had IN-"active" strains. The authors subsequently use some of the INactive strains and submit them to physical processing by filtering and by refreezing the strains as well as to chemical processing by bubbling ozone and NO2 through the extract solution. Most of these processing experiments led to null results. These results are certainly publishable, bring value to the field of bioaerosols and fit the scope of the journal. The manuscript can be accepted after the following comments C1 BGD Interactive comment Printer-friendly version Discussion paper have been addressed, and likely after changes are made to improve the discussion of the results, including further quantification, blank data, reproducibility discussion and additional references for the context of the work. Specific comments 1. Title: The title is misleading: the authors' conclusion is that 16% of the tested strains were ice active above-14 oC. I would argue that this percentage does not equate to "widespread". The authors also did substantial work with physical and chemical processing of their material which is not reflected in the title, but could be. For example, something along the lines of "Ice nucleation ability of 65 different Fusarium species: Effects of storage, size and chemical processing" 2. Abstract Why did the authors choose-14 oC as their threshold? This discussion should be added here in the abstract (and in the text as well).