Distribution and Demography of Antarctic Krill and Salps in the Atlantic Sector of the Southern Ocean during Austral Summer 2021–2022
, Ernest Z. Samyshev 3, Natalia I. Minkina 3, Victor V. Melnikov 3,*, Elena S. Chudinovskih 3, Sergei I. Usachev 1, Pavel A. Salyuk 4, Alexander N. Serebrennikov 5, Oleg A. Zuev 6 and Alexei M. Orlov 6,7Round 1
Reviewer 1 Report
I made several annotations in the original PDF file. Please address them. I also wrote in extent to the Editor, I hope he/she shares the most significant passages of my assessment with you.
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer 1 Comments
Review
Paper title: Distribution and Demography of Antarctic Krill and Salps in the Atlantic Sector of the Southern Ocean during Austral Summer 2021–2022
The authors are grateful to respected reviewer for valuable comments and suggestions.
A detailed list can be found below:
L1: Type of the Paper (Rewiev). We changed it to “Article”
Sorry for our inattention. This text was unintentionally retained from the journal’s template, so we removed it.
L3, 25, 47: “of the Antarctic during Austral Summer 2021–2022”
Corrected: “Antarctic” changed to “the Southern Ocean”
L.24 The study was aimed to investigate krill
Sorry for our inattention: word “was” has been deleted
L25: «Comprehensive material was obtained…
The respected reviewer is absolutely right. We decided to change it to «Samples were»
L27: “Sex differences in sex”
L26: Sorry for our inattention: “in sex” – deleted
L30: "salp fields"
Corrected: the word “fields” was deleted
L31, 32: The result indicates the continuing long-term trend of replacement of the Antarctic krill populations by gelatinous zoo-plankton.
This is a good idea not to use the word “trend” because it implies statistical research. We changed this phrase to “The result indicates the replacement of the Antarctic krill populations by gelatinous zooplankton”. In this case, we are talking only about the results of this study
L37: "catching" as a Keyword
Excluded.
L41: "Euphausiacea order"
L40: Corrected: the word “order” was deleted
L47, 55, 161, 548, 622, 628: " of the Antarctic (AsA)"
Corrected: the “Antarctic” has been changed to “the Southern Ocean”. The abbreviation AsA has been changed throughout the text to “ASO”. Lines 46, 47, 49, 54, 159, 393, 442, 546, 568, 616, 622.
L49-50: Phrase “Analysis of krill abundance dynamics over the past 80 years [8] demonstrated almost halved amount decrease in AsA”
L48-49: Rephrased – “Over the past 80 years krill abundance has shown almost halved decrease in the ASO”
L69: “until disintegrate”
L67: Changed to “until they disintegrate”
L87: “The situation has been deteriorating since the 1970s due to the growing penetration of salps into the high latitudes of the southern hemisphere and their ability to form large aggregations”
L85-86: The respected reviewer is absolutely right that it is incorrect phrase. Changed to “Krill abundance has been declining since the 1970s due to the penetration of salps into the high latitudes of the Southern Hemisphere”.
L91-93: “The latter causes legitimate concern since the feeding activity of tunicates is high, and the diet composition of these species coincide, i.e. salps are feeding competitors of both krill and mesozooplankton”
L89: Changed to “The latter causes legitimate concern since the feeding rate of tunicates is high, and the diet composition of these species, i.e. salps are feeding competitors of both krill and mesozooplankton”.
L99-100: “Salps are known to demonstrate the fastest growth rate among metazoans”
L98: Changed to “Salps are also well known for their fast growth rate among metazoans”
L105: “in wind activity”
L104: Changed to “wind patterns”
L112, 594: “Comprehensive oceanographic studies”
L110, 591: Changed to “Oceanographic studies”. Word “Comprehensive” has been deleted
L133: “Contact research methods”
L131: The respected reviewer is absolutely right: better to write “CTD measurements and sampling”
L161 abbreviation “AsA”
Changed to “ASO”
L269, 272, 274, 276, 532, 533: “salinity with a maximum of 34.55 psu”
L267, 272, 274, 530, 531 Corrected: abbreviation “psu” deleted everywhere
L314-317: “Relatively high values of chlorophyll a concentration (1-2 mg/m3 according to ship measurements and 0.5-1 mg/m3 according to satellite data) were observed in the Bransfield Strait closer to the South Shetland Islands during all periods of expedition works in this area: January 20-25, February 1-2 and February 13-14, 2022.
L312-314: Corrected to “Relatively high values of chlorophyll a concentration (1-2 mg/m3 according to ship measurements and 0.5-1 mg/m3 according to satellite data) were observed in the Bransfield Strait closer to the South Shetland Islands” (There is no point in detailing, since we are talking about the entire period of research)
L.346: Figure 7
This figure has been combined with Figure 12. Part of the text has been moved from L.386-395 (because Figure 12 has been deleted). Description in Figure 7 was changed. Misspelling of the word “Length” has been corrected everywhere (L350, 419, 439: Figure 7, Figure 12, Figure 15)
L350, 419, 439: Figure 7, Figure 8, Figure 12, Figure 15
Figure 7 has been combined with Figure 12. Misspelling of the word “Length” has been corrected everywhere. The caption of Figure 7 has been changed.
L352: Phrase “The condition of sexual maturity of krill impacts greatly on this relationship”.
Corrected – moved to Discussion
L397, 398, 473, 474: abbreviation “Ind”
Sorry for our inattention: abbreviation for individuals must be ended with dot.
L409: reference for Figure 13
Changed to Figure 12
L423: Figure 13
Changed to Figure 12
L427: reference for Figure 14
Changed to Figure 13
L427: Figure 14
Changed to Figure 13
L437: reference for Figure 15
Changed to Figure 14
L440: Figure 15
Changed to Figure 14
L.466: reference for Figures 17-18
Changed to Figure16
L.471: Figure 16
Changed to Figure15
L.472-475: Figure 17
Figure 17 has been deleted
L.477: Figure 18
Changed to Figure16
L.481: Figure 19
Changed to Figure17
L501: “Our research data”
Corrected to “Our data”
L580: “Changes in abundance and the response of krill and salp populations to environmental changes are still poorly understood [82−84]. We recorded an almost complete absence of krill at the stations in the Powell Basin. This area was studied by various expeditions on different sections [68,69,71,72,85]”
The respected reviewer is absolutely right that we need to modify this phrase. Changed to” We recorded an almost complete absence of krill at the stations in the Powell Basin. This area was studied by various expeditions on different sections [68,69,71,72,82−85].
- 602, 604, 608, 609: “chlorophyll a” and “mg/m3”
Changed to chlorophyll a” and “mg/m3”
- 631: “Our studies have shown a steady long-term trend towards a decrease in the population of Antarctic krill (from 38 to 75% per decade) and its successive replacement by salps in 632 this water area [8,14,15,90]
Changed to “The result indicates the replacement of the Antarctic krill populations by gelatinous zooplankton, a steady long-term tendency towards a decrease in the population of Antarctic krill (from 38 to 75% per decade) and its successive replacement by salps in this area [8,14,15,90].”
- 635-639: Double text
Deleted
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors,
Your study presents interesting data from a hard-to-reach area. First of all, I recommend correcting English of your manuscript. A lot of sentences do not look as proper English. They are too long, like in the lines 60-65.
Other recommendations for improving your manuscript:
1) Lines 104-109. The purpose of your study should be separated into a separate paragraph, because in the presented form it is lost in the text of the manuscript.
2) In my opinion, the conclusion to your manuscript is too long. First of all, the conclusion implies a brief summary of the content of the paper.
3) Lines 634-639. Here is repeat with lines 640-644.
4) Line 24. Here is an erratum. The name of the species should be in italics.
Author Response
Response to Reviewer 2 Comments
Review
Paper title: Distribution and Demography of Antarctic Krill and Salps in the Atlantic Sector of the Southern Ocean during Austral Summer 2021–2022
The authors are grateful to respected reviewer for valuable comments and suggestions
Point 1: Your study presents interesting data from a hard-to-reach area. First of all, I recommend correcting English of your manuscript. A lot of sentences do not look as proper English. They are too long, like in the lines 60-65.
Response 1: The respected reviewer is absolutely right that the initial version of the paper needs significant improvement of the quality of the English and we have made many corrections that can be seen in the attached text. The text between lines 60-65 has been significantly changed and divided into four sentences:
“During summer, adult part of krill population is located in the surface water layer, usually above the seasonal pycnocline, at an average depth of about 50 m. They have an irregular spatial distribution, which can be explained by their active behavior. Krill often forms surface patches and can search for more favorable environmental conditions. Water dynamics can also have both a direct impact (cumulative effect of gyres) and an indirect one (for example, through changing of the phytoplankton abundance).”
Point 2: Lines 104-109. The purpose of your study should be separated into a separate paragraph, because in the presented form it is lost in the text of the manuscript..
Response 2: The respected reviewer is right: the purpose of our study should be separated into a separate paragraph. Corrected.
Point 3: In my opinion, the conclusion to your manuscript is too long. First of all, the conclusion implies a brief summary of the content of the paper.
Response 3: Yes, the conclusion to our manuscript is too long and we shortened the first paragraph:
A comprehensive analysis of the obtained data demonstrated that, although any significant shifts in the thermohaline structure and in the currents of the upper 200m water layer in the area of the Antarctic Peninsula were not pronounced compared with the previous observations, distinct local changes were identified. These changes in the currents and structure of waters in the Bransfield Strait and Antarctic Sound can have a significant impact on the entire region.
Changed to:
The analysis of the obtained data demonstrated significant shifts in the thermohaline structure and currents of the upper 200-meter water layer in the Antarctic Peninsula area.
Point 4: Lines 634-639. Here is repeat with lines 640-644.
Response 4: Sorry for our inattention. Corrected
Point 5: Line 24. Here is an erratum. The name of the species should be in italics.
Response 5: Formatted
Author Response File: Author Response.docx
