Size Distribution and Variation in Surface-Suspended Sediments in the North Passage Estuarine Turbidity Maximum of the Yangtze Estuary

Round 1

Reviewer 1 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The authors have done a good job in revising the manuscript which is now much improved. However, the manuscript reads more like a graduate thesis and a technical report. The paper may become publishable if additional improvement can be made, including:

1)      restructuring sections 3 and 4 by removing subtitles 3.2.1, 3.2.2, 3.2.3., 3.3.1, 3.3.2, 3.3.3, and 4; and changing 4.1 to 3.4 and changing 4.2 to 3.5; and renumbering all 5 with 4

2)      the manuscript should be proof-read by a proficient English writer before submission

3)      highlight the scientific merit of this work in abstract and conclusions

 

Some specifics:

There are many language grammar and usage errors. I gave up to correct them all.

Line 18: Please spell out “ETM” when it first time appears.

Line 24: Please spell out “SSSC” when it first time appears.

Lien 193: Change “m3s-1” to “m³ s^-1” throughout the manuscript

Line 200: Change “kgm-3” to “kg m^-3” throughout the manuscript

Line 212: Change “ms-1” to “m s^-1”. Let me be clear here: No one should be allowed to graduate from Hohai University with this kind of technical carelessness

Line 351: Change “studied period” to “study period”

Line 360: Change “figure” to “Figure”

Line 368: Change “lost” to “loss”

Comments on the Quality of English Language

There are many language grammar and usage errors. I gave up to correct them all.

Author Response

the File has been uploaded 

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

The manuscript focuses on the distribution and variation of surface suspended sediments in the North Passage of the Yangtze Estuary. The researchers collected data on sediment concentration and particle size at 15 hydrological sites over a period of three years, from 2016 to 2018. The main objective of the study is to analyze the spatial and temporal patterns of sediment and particle size and their potential impact on the estuary. The findings indicate that extreme weather events have an influence on the hydrological and subsequently sediment dynamics of the area.

 

Significant research efforts have been made in understanding sediment dynamics in estuarine turbidity maximum using various approaches such as remote sensing, numerical modeling, and field data analysis. However, a reader would appreciate more detailed information on how the current major findings compare to the other case studies in the recent literature. 

 

I do not think that the use of climate change being responsible for the trends discussed herein has been sufficiently substantiated. I would suggest removing or justifying its use in the main text. 

 

Introduce the full text before any abbreviation (eg Line 18 amongst others).

 

Avoid needlessly using non-standard text formatting e.g. capitalisation unless necessary (eg. Line 18 amongst others).

 

Please use consistent formatting throughout the document (e.g. see indentation for the first three paragraphs in section 1).

This also applies to the formatting of sub-headers that have mixed and inconsistent formatting - not according to the journal guidance.

 

Is Figure 2 missing?

 

Text in Fig. 1 is illegible: please rectify by increasing the text font size in any figure text.

Likewise the text font size in the sub-figure axes for Fig 3 show increase and style between figures kept consistent and uniform.

 

Check that Fig 4 and 5 are correctly referenced given that 5 was misplaced before fig 4.

 

Place each fig on its own column not in a two column format for Figs 4-7. Ensure the text is legible and formatted consistently for the resulting figures - also for fig 15 and 16 (for that figure also remove the frame in the figure and caption).

 

There is a lot of data shown in all the figures provided but it is unclear whether all these are needed and if there are properly and fully discussed. As a guideline, one should avoid plotting a figure just because they want to show data points - instead one should focus on showing and prioritising the figures with data that are well discussed and contribute towards the main trends that are the focus of this manuscript.

Comments on the Quality of English Language

Ok

Author Response

the file has been uploaded 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The authors have made meaningful changes and the structure of the paper is good now. The manuscript sees to have cited 52 papers, but the references includes only 31.The authors must do a thorough citation check.

Additionally, some mirror changes should be taken before the paper can be published:

 

- Tang et al (13), in line 54 is missing in References.

- All citations beyond 31 are missing in References

- Line  396: remove ":"

- Line 489: remove ":"

 

Comments on the Quality of English Language

The quality of English in fine.

Author Response

The response's file has been uploaded

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

Thanks for considering my comments

Author Response

The response's file has been uploaded

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 Review report: SIZE DISTRIBUTION AND VARIATION OF SURFACE SUS-2 PENDED SEDIMENTS IN NORTH PASSAGE OF YANGTZE 3 ESTUARY

 

Recommendation: Decline the submission

           

            This article reports suspended solid concentration and bed particle size, collected at 15 stations during 2016-2018 at the Chongming River mouth, Yangtze estuary. Reading from its title and its Introduction, I felt excited and expected to see the correlation between the hydrodynamics and the sediment variation between these jetties. Unfortunately, after reading the Method and the Results, the authors disappointingly failed to make any correlation or in-depth analysis. The result is just a simple field report on suspended solid concentration and bed particle size during spring tide and neap tide, even ignoring flood tide, ebb tide, river runoff, and wave actions.

            Moreover, most references are quite old (more than 5 years ago). I guess that the authors must have written this article 5 years ago. Although there are tens of published articles on this topic, the authors did not update their literature review.

 

            Introduction

            - I admit that the Introduction is written well. Reading it feels ambitious. The gap in the literature mentioned in Line 77-79 is interesting. Nevertheless, the authors did not analyze anything they mentioned except simply report the suspended solid concentration and bed particle size. Not even a hydrological condition and seasonal variation is presented.

            - The estuary mouth is complex, especially wave action, wave shoaling, and breaking. Moreover, the sampling stations were inside the jetties, making the water current flow even more complex. It is an interesting study site, but the authors failed to present the hydrodynamics between the jetty and the navigation channel.

 

            Materials and Methods

            - The study area was only at the estuary mouth, thus the article’s title is misleading. The Yangtze River is 6,300 Km long. The study cannot represent the whole river.

            - Ln 107, the information is too old. Only 2015? That is why I presume that this article was written many years ago. The authors did not update the data and the related literature.

            - What method did you use to collect the samples?

            - How did you measure the water current velocity? An ADCP? How did you consider water stratification? Did you assume the depth-averaged velocity?

            - No information about wave actions, despite the fact that this area is subjected to waves. Waves have great impacts on water current and suspended sediment concentration.

            - Line 143-152; if you tabulate the date and time of the data collection, you will realize that your sampling time is questionable.

            - Did you collect the suspended solid concentration and bed particle size at the same hour? Did you know that tide and wave characteristics at the river mouth change hourly?  Imagine, if you collect a sampling at Station A, then sail your boat to collect at Station C, D, E. The time you spent to relocate will move from flood tide to ebb tide. Definitely, flow direction and velocity will change, and the suspended sediment concentration will inevitably change.   

 

           

            Results and Discussion

            - This is the most disappointing section. The authors did not even report the water current measurements covering flood tide, ebb tide, water discharge volume, tidal variation, tidal range, and gradient. They simply presented the suspended solid concentration and bed particle size along their 9 stations.

            - The correlations of hydrological and wave conditions with the suspended solid concentration and bed particle size are required. The authors just completely failed to reach the gap that they ambitiously wrote in the Introduction.

 

            I still have many more minor comments (I did not type it here), but I believe that my abovementioned opinion is enough to support the Editor to decline this submission.     

             

 

Comments on the Quality of English Language

-

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript needs substantial improvement before it can be accepted. The paper lacks clear description of science merit, research objectives, and testable hypotheses of this study. The paper reads like a technical report, rather than a research article, without an in-depth discussion of the findings.  Numerous studies have been conducted in the Yangtze River estuary and other coastal rivers. The authors need to introduce what is known, what is unknown, and what is the goal of this study on grain size distribution. The research methods are rudimental lacking novel numeric analysis. Also the paper needs a thorough editing by a proficient English writer. 

 

Introduction:

There have been numerous studies on sediment transport and geomorphology of the Yangtze River estuary. Some of the recent studies should be introduced to give the readers a background about the subject, including:

 Tang, Ming, Heqin Cheng, Y. Jun Xu, Hao Hu, Shuwei Zheng, Bo Wang, Zongyong Yang, Lizhi Teng, Wei Xu, Ge Yan, Erfeng Zhang, Jiufa Li. 2022. Channel bed adjustment of the lowermost Yangtze River Estuary from 1983 to 2018: Causes and implications. Water,  https://doi.org/10.3390/w14244135

Zheng, S., Y.J. Xu, H. Cheng, B. Wang, W. Xu, and S. Wu. 2018. Riverbed erosion of the final 565 kilometers of the Yangtze River (Changjiang) following construction of the Three Gorges Dam. Scientific Reports doi:10.1038/s41598-018-30441-6.

Wu, S., H. Cheng, Y.J. Xu, J. Li, S. Zheng and W. Xu. 2016. Riverbed Micromorphology of the Yangtze River Estuary, China. Water doi:10.3390/w8050190.

Wu, S. H. Cheng, Y.J. Xu, J. Li, S. Zheng. 2016. Decadal changes in bathymetry of the Yangtze River Estuary: Human impacts and potential saltwater intrusion. Estuarine, Coastal and Shelf Science doi:10.1016/j.ecss.2016.10.002.

Zhang, Weiguo, Y. Jun Xu, Leicheng Guo, Nina S.-N. Lam, Kehui Xu, Shilun Yang, Qiang Yao, Kam-biu Liu. 2022. Comparing the Yangtze and Mississippi River Deltas in the light of coupled natural-human dynamics: Lessons learned and implications for management. Geomorphology doi:10.1016/j.geomorph.2021.108075.

L38-40: "recently"? That is not true. Suspended sediment transport in rivers has been investigated intensively and extensively in the world for at least half a century.

L56: Change "Estuarine" to "estuarine"

L59: SSC is typically used for suspended sediment concentration, not characteristics.

L79-85: I'd suggest to focus on science merit of this study.

L98-101: What are the specific objectives of this? Please list them here.

Methods:

L108-109: In the recent decades, the lower Yangtze River has a much lower sediment load, i.e., less than 1/4 of 480MT/yr-1. 

Results:

This section is too lengthy and should be shortened. For instance, remove "a. b, c year" subtitles; Instead, explain the difference among the years.

This section is too lengthy and should be shortened. For instance, remove "a. b, c year" subtitles; Instead, explain the difference among the years.

Have you done any statistical testing to see if the grain size distribution is statistically different among the seasons and years?

L196: Change  "kgm-3" to "kg m^-3"

L188-189: Remove the sentence

Conclusions:

The Conclusions section in its current form reads like a mix of discussion and summary. I'd suggest the authors to remove all the citations and, instead, write a separate Discussion section. 

The Conclusions section should highlight what is new in this study, and what are the implications for management. 

Comments on the Quality of English Language

The paper needs a thorough editing by a proficient English writer.