Contribution of Atmospheric Depositions to Inventory of Nutrients in the Coastal Waters of Crimea
Nicole Jeffery
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
We are grateful for the reviewer, who have suggested in depth reviews for our manuscript and proposed many helpful remarks. We have accounted all remarks and made appropriate changes in our initial text. We have followed and made the suggested changes in many cases and we have added the requested explanations to clear our messages in some cases.
We have carefully read and have improved the English language in the article. All changes in the text have been made in the trace changes mode to make them easy for identification. Yet, we suggest also our comments below for all issues raised by the reviewers.
Reviewer 1.
- “The dataset is also valuable, for additional studies and to provide independent verification of your results. I don’t see a link in the paper as to how the data will be shared with the community.”
Data Availability Statement: All the data and additional information supporting the findings of this study are available from the corresponding authors upon reasonable request.
- “Throughout the analysis, uncertainties are not computed and not included in figures. Measurement errors are given but not propagated through calculations.”
We have added requested information on measurements errors and uncertainties throughout the text, where it is appropriate.
- “A regression expression is stated (with missing units) and used over 2009-2014 but not validated over 2004-2008 or 2015-present. How good is the fit over time periods where you have data? This needs to be done.”
We have validated the used regression expression and added information to the text.
- “Simple calculations are missing. For example, what is the correlation between VWM and precipitation volume in your study area? Does the regression expression reproduce this relationship? How does the total input of a given nutrient for each rain event compare to the mixed layer content of that nutrient? From that comparison you can calculate an estimate of the maximum possible increase from precip. alone. How does this compare to what you actually measure in the surface?”
Some calculations have been done and information is added to the text. Yet, we cannot “estimate the maximum possible increase from precipitations alone” for that reason that it depends on later water dynamics and vertical exchange, which are variable. The suggested simple calculations would request a 3-D modeling including water dynamics and biogeochemical simulations. We have limited our analysis to observational data and calculated with the verified regression expression. The major purpose of this work is to demonstrate that atmospheric precipitations, which are often neglected, are important for a short term events on the scale of several days. Yet, when averaged on the annual time scale the role of coastal sources of nutrients remains primary.
- “Where do the ambient nutrient values come from? There are no references for this, and from methods, there’s no indication that surface layer sampling was done before precipitation events. In general, references are insufficient. If the authors quote a measurement, procedure or estimate from another source, then it should reference (see paragraph L63-73, L86, L209-210...)”
We have added information to the text. We have considered typically measured background values as ambient values. The purpose of our work is to demonstrate a substantial increase of the measured concentrations of nutrients after events of atmospheric precipitations. This is usually neglected comparing to other sources of nutrients. Yet, this source is important even for coastal areas, but it’s importance is recognized at the time scale of days.
- “How much data was collected? I have no idea. This should be in the Methods. How many precipitation events occurred between 2004-2008 for example? How many surface water samples were collected? In Table 1 and 2, the Max / Min of your data set is not particularly informative. How about some seasonal information? Or the mean of the total nitrogen deposited?”
This information has been added to the text.
- “The Figures and figure captions are incomplete and have multiple errors. All need uncertainties/error bars. Where is figure 2? Figure 3 to 6 – Instead of just an arrow and the word precipitation, include the atmospheric nutrient deposition flux associated with the precipitation event. Figure 5 caption says phosphorus and silica but the y-axis says inorganic nitrogen? Again, what is the ambient value? Table 1 “statics”. Figure 8 define flux(1:5), Units? How did you fill the missing values? Interpolation? What are the dash dotted lines? Figure 7. VWM vs precipitation amount is given only for nitrogen. What are the relationships for phosphorus and silica? Provide some physical explanation for these relationships, and why they might be the same or different. Is this a result of seasonality in emission sources or rather more due to atmospheric processes?”
We have corrected errors. That was our fault. We have also added the requested additional information and plots.
- “Discussion: Your explanations and conclusions need more support. In the intro you state that during heavy rains, the runoff volume from the Chernaya River may be comparable to the Bay volume. How are you separating the impact of direct precipitation from enhanced river-runoff? Is there gauge data to support your conclusions? You also provide evidence that stormwater runoff of wastewater is high in nitrate and phosphate. How are you accounting for these sources during heavy rains?”
Some explanations have been added to the text. We have chosen the site for seawater sampling far enough from all local coastal sources of nutrients, including the river mouth and outlets. Those sources do contribute to the budget of nutrients in the bay, but it works due to water mixing in the bay on the time scale of weeks to months.
- “Strong stratification and weak mixing are discussed but no values are given and no measurements provided from other sources. Similarly, advective transport of pollutants from other sources is hypothesized to have occurred on July 4. Why only then?”
We have added a plot and information in the text.
- “Introduction needs a better description of the study area waters, depth, mixed layer depths, stratification, their seasonality. Less on motivation that is never discussed again (for example, dead zones).”
Some changes in the text have been made following these suggestions.
- “You need to clearly indicate throughout whether you mean precipitation or wet plus dry deposition. Your results suggest that dry deposition may be important particularly for phosphorus and silica. Can you elaborate in the discussion? For example, do you expect to see comparable dry deposition fluxes outside of precipitation events?”
We have added information to recognize between wet and dry depositions. To make it clear. Dry depositions are also events for long-range dust transportation. We have demonstrated this issues in other publications (Varenik, A.V.; Kalinskaya, D.V. The Effect of Dust Transport on the Concentration of Chlorophyll-A in the Surface Layer of the Black Sea. Appl. Sci. 2021, 11, 4692. https://doi.org/10.3390/app1110469; D. V. Kalinskaya, A. V. Varenik, "The research of the dust transport impact on the biogeochemical characteristics of the Black Sea surface layer" Proc.SPIE 11208, 25th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, 1120845 (18 December 2019); doi:10.1117/12.2540432).
- “VWM for silica in rain is lower than mean oceanic surface values. Comment on this. What are the implications?”
This means that rains are not important to raise the concentration of silica in seawater.
- “Paragraph 313-330 needs uncertainties.”
We have taken these values from the referenced publications and sites.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments on Contribution of atmospheric depositions to inventory of nutrients in the coastal waters of Crimea
General:
The author presented a consistent set of data, including concentrations in the rainfall measured during large periods that would yield very interesting research. However, the approach is not quite supported in evidences of science. Many pitfalls were presented concerning the writing, organization and concepts within my following comments. An extensive rethinking of the approach is necessary in order to have these data ublished in a scientific journal. I strongly advise authors to do this job, because your data are very interesting.
Abstract
Line 11: undesirable is way too vague, indicate pollution, environmental degradation, or other…
Line 13: Why you limit impact to surface layer of seawater?
Line 18: regression was used to calculate the relationship between concentrations (which is very clear) and meteorological conditions (which is not clear). Would you explain the Variable?
Line 20: This is far from clear: What you mean for shorter time scales? Why fluxes are smaller in shorter time scales? Normally, fluxes are smaller in drier periods.
Line 23: Ambient concentration? Isn’t it upper layer water concentration?
Introduction
A careful revision of the English has to be done. There is a lot of issues nd loose words. For instance, line 29 inputs are not introduced to the budged. Input should go into the marine environment… Processes of organic matter recycling. Actually, processes is an useless word. An so on…
Line 36: I’m not perceiving the meaning of this word scale. It has for you probably a different meaning. This should be corrected.
Line 40: a reference is necessary for this statement.
Figure 1: The quality of the figure should be considerably improved. The path of the river is barely visible. On the other hand a smaller map showing the position of the study area on a broader map is necessary
Line 55: km3 per year is a very difficult unit. Try m3 per second. In the sequence, it cannot be higher in rainy periods, because the unit is given by year, so it included rainy periods.
Line 57: give some figures. What is the volume of the bay, how long can las a heavy rain? Just give these figures between parantheses).
Line 60: hould be rephrased. What you mean for water area? I did not understand how nutrient input support high input of organic matter. It may support a primary production that becomes organic matter, but how could it influence the input of organic matter?
It is strange that you present a brief introduction and then starts to describe the study area, on line 63 you go back to a theoretical reference, discussin sources of contaminants to the atmosphere.
The following paragraph (from line 63). All these figures, sources of contaminants to the atmosphere should have their own reference. The las one in the paragraph should not so broad to justify all the statements.
Line 84: This period requires a reference
Line 88: You should name the authors, because the reference appears after.
Line 90: another unit 56 million m3 per year. It becomes very difficult to compare.
Line 91: What is an emergency outlet? Is it wet weather sewage outlet?
Line 92: Do you refer to the water that is released from these “emergency” outlets?
Line 99: Is your focus on atmospheric inputs, or on biogeochemical cycle. It is not cleat from the last paragraph of the introduction.
Material and Methods
Line 108: I Guess now is already last year. In five uears it will continue to be now. Just put the last sampling year.
Figure 1 on line 110 is the second Figure 1. A less pictorial map should be better. Besides, it looks like this image is a fragment of another map. Beware with rights of this map.
Line 112: Samples were collected..
Line 118 collect the sun… do you mean summation? Or total
Line 122: A map with the position of the sampling sites is absolutely necessary. How many samples. How were them collected? Surface, sub-surface? Is there a sampling strategy?
Lines 131 and forward: I need references for the methods to analyze nitrite, nitrate, phosphate and dissolved silica. For the method for the analysis of ammonium, a brief description of the method is necessary, because the reference in not current, broadly applied method. The simple statement that the methods attained a 10% error is not enough. You should described how you reach this precision, repeated analyses of the same sample? Reference material? Blanks? Other?
Calculation of the volume weighted mean concentrations: A better explanation of this concept is necessary. I wonder you did not weighed rainfall volumes, nor did you measured concentrations by weighting something, so why did you used this term?
Multiple nonlinear regression: when you calculated the multiple regression to estimate nitrogen concentrations for the period 2009-2014 there is probably a considerable imprecision associated. In order to evaluate this precision you should apply this equations to the years you have concentrations. That would a sort of calibration of the method to your own samples.
Line 180-183: This is useless. Just remove this paragraph, because you have already state the aim of your work in the introduction
Lines 195-198: You took the decision of separating results from discussion. Although it is broadly applied, in my opinion this is a bad choice. But I’d would accept this choice. However, in these lines you start interpreting your differences, which is a matter for discussions. In the results part you just present your data. In the discussion you present your interpretations (although, as I said, it is a bad choice). Whether you can change this to a gathered results and discussion (meaning you have to re-write and reorganize everything) , otherwise you can stick to the separate form, but respecting their characteristics.
Lines 199-200: just remove this period.
Lines 200-207: Where is this information obtained from? Is there a graph, a table that shows the concentrations during summer and winter. You must mention it here.
Figure 3: It is evident that now a detailed description of the strategics for sampling bay water is missing in the material and methods. Why did you sampled only on the days of 2018?
Figure 4: Where did you get these “ambient values”?
Lines 224-225: More interpretation…
Lines 235-248: Do you have any evidence (CTD) of this lack of stratification? So it is difficult to state this hypothesis.
I just wonder that normally when you have large rainfall events, riverine inputs are rapidly intensified and promote modification of the quality of the water in the adjacent systems (bays and coastal areas). This increase in concentrations/flows are mainly due to leaching of the soils and sediments of the drainage. I’m not convinced that the concentrations are mainly from rainfall concentrations. Actually, I’m quite sure.
Discussion
Well, you start your discussion showing new data. These VWM results were not shown in the part results.
Line 280: I could not find any Figure 9a. Do you mean 8a?
In the sequence, it is difficult to be convinced with your statements: First I still did not understand well what is your VWM. This should be better explained in the material and methods. Second, When I see your graphs, it is possible to see that you chose semestrial averages, which is not consistent with variations in rainfall. Sometimes you have very short events that contribute with all nutrients of one month and getting average of one whole semester further complicate things.
Line 288: where did you get this expected (or calculated) data that fit well measured values?
I think that the discussion that follows, which is a kind of nutrients balance of inputs to the bay lacks a main point which is leaching of the soils during heavy rains. This should be the inputs attributed to rivers in your balance, but are also associated with rainfall. However, concentrations of the rainfall are not responsible for the increase in concentrations.
Lines 366-367. You have to cite at least 3 of these references that confirm your point.
Line 367: the reference was located in the wrong place. Please correct it.
Conclusions:
The first paragraph is not really a conclusion of your research. I’d suggest it to be withdrew.
Your conclusion is quite simplified, which is not bad, but some support has to be stated in this part of the text. I think you don’t have this support. You have a quite extensive amount of data in the rainfall, which can bee a relevant contribution to the understanding of nutrients in rainfall, however, I think your approach is incorrect and you should rethink your data.
Author Response
We are grateful for the reviewers, who have suggested in depth reviews for our manuscript and proposed many helpful remarks. We have accounted all remarks and made appropriate changes in our initial text. We have followed and made the suggested changes in many cases and we have added the requested explanations to clear our messages in some cases.
We have carefully read and have improved the English language in the article. All changes in the text have been made in the trace changes mode to make them easy for identification. Yet, we suggest also our comments below for all issues raised by the reviewers
- “Line 11: undesirable is way too vague, indicate pollution, environmental degradation, or other…”
We have done it.
- “Line 13: Why you limit impact to surface layer of seawater?”
Yet, the major purpose of our work is to demonstrate the importance of atmospheric precipitations of nutrients for the euphotic zone, where nutrients are utilized by phytoplankton. It would take 3-D modeling in combination with high resolution monitoring to account for the entire volume of waters. But that would also result in many other uncertainties.
- “Line 18: regression was used to calculate the relationship between concentrations (which is very clear) and meteorological conditions (which is not clear). Would you explain the Variable?”
We have done it in the text.
- “Line 20: This is far from clear: What you mean for shorter time scales? Why fluxes are smaller in shorter time scales? Normally, fluxes are smaller in drier periods.”
We demonstrate that atmospheric precipitations are important on the time scale of these events, hours to days. When integrated on the annual scale, these sources of nutrients are less important than other coastal sources.
- “Line 23: Ambient concentration? Isn’t it upper layer water concentration?
We have added information to the text. We have considered typically measured background values as ambient values.
- A careful revision of the English has to be done. There is a lot of issues and loose words. For instance, line 29 inputs are not introduced to the budged. Input should go into the marine environment… Processes of organic matter recycling. Actually, processes is an useless word. An so on…”
We have done appropriate changes in the text.
- “Line 36: I’m not perceiving the meaning of this word scale. It has for you probably a different meaning. This should be corrected.”
We have done it.
- “Line 40: a reference is necessary for this statement.”
It has been added.
- “Figure 1: The quality of the figure should be considerably improved. The path of the river is barely visible. On the other hand a smaller map showing the position of the study area on a broader map is necessary.”
We have done it.
- “Line 55: km3 per year is a very difficult unit. Try m3 per second. In the sequence, it cannot be higher in rainy periods, because the unit is given by year, so it included rainy periods.”
We have done it.
- “Line 57: give some figures. What is the volume of the bay, how long can last a heavy rain? Just give these figures between parentheses.”
We have added information.
- “Line 60: Should be rephrased. What you mean for water area? I did not understand how nutrient input support high input of organic matter. It may support a primary production that becomes organic matter, but how could it influence the input of organic matter?
It is strange that you present a brief introduction and then starts to describe the study area, on line 63 you go back to a theoretical reference, discussion sources of contaminants to the atmosphere.”
We have made some changed in the text to make it clearer.
- “The following paragraph (from line 63). All these figures, sources of contaminants to the atmosphere should have their own reference. The last one in the paragraph should not so broad to justify all the statements.”
We have done it.
- “Line 84: This period requires a reference
We have done it.
- “Line 88: You should name the authors, because the reference appears after.
Line 90: another unit 56 million m3 per year. It becomes very difficult to compare.”
We have corrected the text.
- “Line 91: What is an emergency outlet? Is it wet weather sewage outlet?”
Yes, it is a wet weather sewage outlet. We have made changes in the text.
- “Line 92: Do you refer to the water that is released from these “emergency” outlets?”
Yes, we do. We reference and suggest information on various coastal sources of nutrients.
- “Line 99: Is your focus on atmospheric inputs, or on biogeochemical cycle. It is not clear from the last paragraph of the introduction.”
- We have made appropriate changes in the text. We focus on atmospheric inputs.
- “Line 108: I Guess now is already last year. In five uears it will continue to be now. Just put the last sampling year.”
We have corrected this part of the text.
- “Figure 1 on line 110 is the second Figure 1. A less pictorial map should be better. Besides, it looks like this image is a fragment of another map. Beware with rights of this map.”
We have changed the plot and added references.
- “Line 112: Samples were collected..”
We have corrected it.
- “Line 118 collect the sun… do you mean summation? Or total”
We have made appropriate changes.
- “Line 122: A map with the position of the sampling sites is absolutely necessary. How many samples. How were them collected? Surface, sub-surface? Is there a sampling strategy?”
We have made appropriate changes in the figure and in the text to answer these questions.
- “Lines 131 and forward: I need references for the methods to analyze nitrite, nitrate, phosphate and dissolved silica. For the method for the analysis of ammonium, a brief description of the method is necessary, because the reference in not current, broadly applied method. The simple statement that the methods attained a 10% error is not enough. You should described how you reach this precision, repeated analyses of the same sample? Reference material? Blanks? Other?”
We have added this information to the text.
- “Calculation of the volume weighted mean concentrations: A better explanation of this concept is necessary. I wonder you did not weighed rainfall volumes, nor did you measured concentrations by weighting something, so why did you used this term?”
It is the standard method to average concentrations for several precipitation events of various intensity. Data on concentrations and precipitation amounts are used to get mean values of concentrations. [Bhuyan, P., Ahmed, M.S., Hopke, P.K. and Hoque, R.R. (2020). Understanding the Chemistry and Sources of Precipitation Ions in the mid-Brahmaputra Valley of Northeastern India. Aerosol Air Qual. Res. 20: 2690–2704. https://doi.org/10.4209/aaqr.2020.02.0072].
- “Multiple nonlinear regression: when you calculated the multiple regression to estimate nitrogen concentrations for the period 2009-2014 there is probably a considerable imprecision associated. In order to evaluate this precision you should apply this equations to the years you have concentrations. That would a sort of calibration of the method to your own samples.”
Information has been added to the text.
- “Line 180-183: This is useless. Just remove this paragraph, because you have already state the aim of your work in the introduction.”
This paragraph has been deleted.
- “Lines 195-198: You took the decision of separating results from discussion. Although it is broadly applied, in my opinion this is a bad choice. But I’d would accept this choice. However, in these lines you start interpreting your differences, which is a matter for discussions. In the results part you just present your data. In the discussion you present your interpretations (although, as I said, it is a bad choice). Whether you can change this to a gathered results and discussion (meaning you have to re-write and reorganize everything), otherwise you can stick to the separate form, but respecting their characteristics.”
We agree and we have joined two sections together.
- “Lines 199-200: just remove this period.”
We have done it.
- “Lines 200-207: Where is this information obtained from? Is there a graph, a table that shows the concentrations during summer and winter. You must mention it here.”
We have added data and information to the text.
- “Figure 3: It is evident that now a detailed description of the strategics for sampling bay water is missing in the material and methods. Why did you sampled only on the days of 2018?
Figure 4: Where did you get these “ambient values”?”
We have added information to the text.
- “Lines 235-248: Do you have any evidence (CTD) of this lack of stratification? So it is difficult to state this hypothesis.”
We have added another plot and explanations to the text.
- “I just wonder that normally when you have large rainfall events, riverine inputs are rapidly intensified and promote modification of the quality of the water in the adjacent systems (bays and coastal areas). This increase in concentrations/flows are mainly due to leaching of the soils and sediments of the drainage. I’m not convinced that the concentrations are mainly from rainfall concentrations. Actually, I’m quite sure.”
Some explanations have been added to the text. We have chosen the site for seawater sampling far enough from all local coastal sources of nutrients, including the river mouth and outlets. Those sources do contribute to the budget of nutrients in the bay, but it works due to water mixing in the bay on the time scale of weeks to months.
- “Line 280: I could not find any Figure 9a. Do you mean 8a?”
It has been corrected.
- “In the sequence, it is difficult to be convinced with your statements: First I still did not understand well what is your VWM. This should be better explained in the material and methods. Second, When I see your graphs, it is possible to see that you chose semestrial averages, which is not consistent with variations in rainfall. Sometimes you have very short events that contribute with all nutrients of one month and getting average of one whole semester further complicate things.”
We have added information in the text. It is the major issue of this paper. When annual contributions of nutrients are compared, atmospheric precipitations are far less important than coastal sources. Yet, atmospheric precipitations are important at the daily time scale when precipitation happens.
- “Line 288: where did you get this expected (or calculated) data that fit well measured values? I think that the discussion that follows, which is a kind of nutrients balance of inputs to the bay lacks a main point which is leaching of the soils during heavy rains. This should be the inputs attributed to rivers in your balance, but are also associated with rainfall. However, concentrations of the rainfall are not responsible for the increase in concentrations.”
We have added information to the text.
- “Lines 366-367. You have to cite at least 3 of these references that confirm your point.”
We have added references to the text.
- “Line 367: the reference was located in the wrong place. Please correct it.”
We have done it.
- “Conclusions:
The first paragraph is not really a conclusion of your research. I’d suggest it to be withdrew. Your conclusion is quite simplified, which is not bad, but some support has to be stated in this part of the text. I think you don’t have this support. You have a quite extensive amount of data in the rainfall, which can be a relevant contribution to the understanding of nutrients in rainfall, however, I think your approach is incorrect and you should rethink your data.”
We have corrected the text of conclusions.
Round 2
Reviewer 2 Report
I'm quite satisfied with the new version. Just a few comments. English is to be improved in the final version. There are still many style pitfalls. The introduction of the article do not describe the context of the research and should be further improved. There are many analytical details in the methods that are not necessary, because the chemical procedures are broadly applied in the literature.
The presentation of the results and the discussions are considerably clearer and the improvements made the research interesting.
Author Response
We are thankful to the reviewer for comments. We have accepted them and made appropriate changes in the text. We have carefully read and improved English in the article.
