Manuscript number: bg-2017-469
First of all I would like to thank the authors (Turpault et al.) for their response. However, I am quite unsatisfied with the revised manuscript, although Turpault et al. answered all comments of reviewers # 1 & 2 in an extensive way.
I know, errare humanum est (to err is human) and I do not want to be too fussy, but the amount of errors in the current manuscript is just too big to be ignored, which makes it really frustrating to read and to review the article at all. This is especially annoying as this manuscript was approved by five (!) authors in its current form.
From my point of view the manuscript in its current form is not publishable, although I think the results generally are of interest for the readers of BIOGEOSCIENCES.
I recommend Turpault et al. a second and careful major revision of their manuscript. In this context, the authors should address the following points:
• Please double-check the citations and the reference list according to the following points:
- A lot of citations were deleted (especially in the introduction), but still appear in the reference list (e.g., Iler, 1979; McKeague and Cline, 1963; Dixon and Weed, 1989) on the one hand.
- On the other hand, a lot of citations were added, but are not listed in the reference list (e.g., Struyf and Conley, 2012; Puppe et al., 2014; Conley, 2002).
- Some citations are not correct at all (e.g., ‘Sommers et al.’ should be ‘Sommer et al.’, what is ‘Conley et al., 2002’? Do you mean ‘Conley, 2002’?).
- Please avoid redundant credits (e.g., change ‘Cornelis et al., 2010a; Cornelis et al., 2011a’ to ‘Cornelis et al. 2010a, 2011a’).
- Please correct ‘et al’ to ‘et al.’.
• If you introduce an abbreviation you should use it (so please change ‘biogenic Si’ to ‘BSi’).
• Diatoms and testate amoebae are no animals by definition (animals are multicellular, eukaryotic organisms). Please correct to ‘Other important producers of BSi are sponges and protists (diatoms, testate amoebae)…’.
• Please change ‘Dsi’ to ‘DSi’.
• I would recommend adding ‘Maguire et al.’ in the introduction as this article is quite important regarding the current knowledge of the scientific background of your study.
• You state in your answers that ‘all samples were observed with binocular microscope but only some samples of fine roots were observed by SEM-EDX (see part 2.3.4. Microscopic analysis)’. However, in the corresponding section of your manuscript I can read ‘The samples were examined at the GeoResources laboratory … using a scanning electron microscope…’. This suggests that all samples were analyzed with SEM-EDX. Please specify in your manuscript which samples were analyzed and how these samples were chosen. In addition, you should, of course, mention (if only shortly) the results of these analyses in your manuscript, because checking your fine root samples for adhering soil particles (as a Si source) is crucial for your work.
• You state in your answers that ‘the Kruskal-Wallis test is also a non-parametric test used to test at least three samples’. This is correct. However, in the corresponding point of criticism in my first review I referred to your statement ‘The significance of differences in element content between the gravitational and bound solutions and between plots was tested by the Student’s t-test’ in your manuscript. So again my point: If your data are not normally distributed (as you said before) you should use nonparametric tests only (i.e., the Mann-Whitney U test instead of the Student’s t-test).
• L. 382/383: Please correct ‘2.4.106’ and 7.2.105’ to ‘2.4 x 106’ and 7.2 x 105’.
• I miss a reference to figures 6 and 7 in your results section.
• L. 436: Please correct ‘…fine roots was very higher…’ to ‘…fine roots was higher…’
• L. 439: Too many dots after ‘sugar maple fine roots’.
• L. 441 & 443: You still use incorrect units (‘t.ha-1’). Please follow the rules of the ‘International System of Units’.
• L. 477: Please correct ‘…a part of the Si from the phytoliths belonged to the protozoic Si pool’ to ‘…a part of the BSi belonged to the protozoic Si pool’.
• By the way, you did not explain ‘protozoic Si pools’ in your introduction. This makes it difficult for the reader to follow, as not every reader is a specialist in Si cycling and BSi pools. You should give all relevant knowledge for the understanding of your work in the introduction or at least give a short explanation in the corresponding passage.
• L. 493: What is meant by ‘(51 6)’?
• L. 567: Please cite ‘Bauer, Elbaum & Weiss’ as ‘Bauer et al.’.
• Fig. 2: Please correct the unit (y-axis).
• Fig. 3: I miss a caption of the y-axis.
• Fig. 4: Please correct the units (y-axis).
• Fig. 6: Not all data are given in the corresponding colors (see data for ‘organic horizons’ and ‘small dead woods’).
• Fig. 7: Please state references for ‘L’ in the caption of Fig. 7 and add units for the presented data.