Recent Ostracod Fauna of the Western Ross Sea (Antarctica): A Poorly Known Ingredient of Polar Carbonate Factories

Round 1

Reviewer 1 Report

Manuscript “Recent ostracod fauna of the Western Ross Sea (Antarctica): A poorly known ingredient of polar carbonate factories” fills some important gaps in or knowledge of Southern Ocean biota and their ecology, for this reason it is important piece of work. I am not sure, however” if “Minerals” is the best choice to publish these data.

Anyhow, there are several major points that should be considered by the authors while revising this work.

1.      The major bathymetric features of the RS are the shallow-water banks, which differ with the rest of the continental shelf by different bathymetry, temp, salinity, and sediment type. It would be good to better mark/highlight these features on all maps, including Fig. 1.

2.      Fig. 2 shows bottom not surface water temperatures and salinities, right? This should be clearly stated. If so, the banks should be clearly recognizable on this maps and they are not. This point may have serious indications. It is not clear what are temp and salinity data used for further statistics. Were these actual measurements at sample sites or they were taken from interpolation showed on Fig. 2? If the second, I have a major problem if these interpolations, not accounting for bathymetry as I expect, reflect real values near the sea floor.

3.      I also have a problem with design of the study and the Conclusions. First of all, ostracods analyzed by the authors are benthic, but there is not a single environmental variable referring to the sediment itself. For this reason, stating in point 2 of the Conclusions that “Salinity and temperature are the oceanographic variables that explain the main variance in the examined samples” may be deceptive. Sediments in the RS may differ substantially depending on bathymetry, local productivity, winnowing, IRD delivery etc. Authors should try to include this factor in their analysis, and my guess is, sediment properties may be more important than temp and salinity (water masses), especially if you consider #2, above. Authors had access to the sediments. Why not to do basic grain-size analysis for sed type, and add TOC and biosilica content for its composition? These data would greatly add to discussion and interpretation!

 

Not so critical, but also important:

It would be good to discuss in a few sentences differences in methods used for recovering samples at different locations. Now, a general info is provided only in the supplementary table. It is good to know if at all sites the water-sediment interface was actually sampled, which is important if we compare “living” assemblages. For comparison between different sites, perhaps surface area of the samples would be more important that its mass/volume. I realize, it may be impossible to keep to a single standard when using archived materials, but a discussion of eventual problems would be helpful.

l. 294-298; all these species are in Cluster 1. Perhaps it is important. And BTW, it would be good to see another figure with a distribution map of these clusters.

l. 312-313; these values look really low. Maybe CCA analysis including only the Clusters, not particular species, would do better. Please see Caulle et al. Live (Rose Bengal stained) foraminiferal faunas from the northern Arabian Sea: faunal succession within and below the OMZ, Biogeosciences, 11, 1155–1175.

Table 3. These data could be better comparable if seen on a graph.

Fig. 6 and all the other figs showing interpolation of ostracod data. These are based on all samples not excluding the barren samples, right? For clarity it would be useful to mark barren samples, or those lacking a particular species for Figs 7 etc with a different color/blank. In Fig. 6A, I have a problem with the scale. In violet, number of species is 0-1. It would be good to distinguish between these two.

Fig. 7 is missing

You have listed three detailed goals of this study. It would help if you structure the Discussion by adding subchapter titles referring to these goals

For discussion of dissolution, broader referring to other calcareous microfossils, which are better studied in the RS (i.e., foraminifera) is needed

In the last point of the Conclusions it is stated “Rising values of the ostracod assemblages were also recorded in and near Terra Nova”. Do you mean diversity and standardized abundances? I do not see it for the inset of TNB in Fig. 6; just south of it yes, but not in the inset.

In many figures letter fonts are very small and difficult to read.

 

Minor points

Abstract; Do not introduce acronyms at this point if not used in the Abstract.

Line 31; “density e diversity” change into “abundance and diversity”

l.58; Ostracods are also…

l.100; Weddell

l.115; introduce WRSS here not in l.120

l.143-146; a reference needed

l. 167 and throughout; avoid single-sentence paragraphs

l. 249; cannot not can’t

l. 396; “undisclosed ostracod diffusion…” I am not sure what you mean.

l. 402; what “its” means - size of the region, population?

l. 427; diffusion?

l. 433; consider these being cryptic species

l.441 etc; do not start sentences with abbreviated genus names.

l.550-552; italics

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

read carefully the notes to the manuscript

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf