Effect of Maritime Traffic on Water Quality Parameters in Santa Marta, Colombia
María Del Pilar Suárez
Round 1
Reviewer 1 Report
This is a nice local (but of international importance!) study of the environmental effects of marine traffic. The paper is concise and informative. Its main problem is the quality of writing. As for the scientific and technical sides of this paper, I think small amendments are required (see below). I guess this will be really good paper after improvements.
- 1: is this your own drawing? If not, please, indicate the source and confirm the permission to republish this.
- Subsection 2.2: please, provide more details about the analyses. What is the lab? Please, explain why only these parameters were measured (e.g., why not heavy metal content or water transparency?).
- Lines 121-123: what is given in bold font here?
- Lines 160-161: what is water quality index?
- Discussion: I encourage to compare your findings to results of some other, similar studies in the other parts of the world.
- Discussion: do your results indicate that tourism-related marine traffic has serious environmental effect? Please, conceptualize and add the general literature. Look at these sources and the literature cited there:
https://link.springer.com/article/10.1007/BF02241824
https://www.mdpi.com/2076-3263/10/6/242
https://www.mdpi.com/2073-4441/11/6/1265/htm
I think these and some (many!) other works can be considered and cited.
- Why not to provide photos of the discussed area?
- The language and some phrasing need heavy correction. Please, ask any English native-speaking colleague to help.
Author Response
Comment: This is a nice local (but of international importance!) study of the environmental effects of marine traffic. The paper is concise and informative. Its main problem is the quality of writing. As for the scientific and technical sides of this paper, I think small amendments are required (see below). I guess this will be really good paper after improvements.
Response: Thank you for your comments. We appreciate the opportunity to improve the manuscript.
Comment: 2.1: is this your own drawing? If not, please, indicate the source and confirm the permission to republish this.
Response: Yes, the map was produced using QGis software
Comment: Subsection 2.2: please, provide more details about the analyses. What is the lab? Please, explain why only these parameters were measured (e.g., why not heavy metal content or water transparency?).
Response: All data used in the present study were obtained from “open data” made available by Surveillance Network for the Conservation and Protection of Marine and Coastal Waters of Colombia. This database has not information on trace metals levels or water transparency.
Comment: Lines 121-123: what is given in bold font here?
Response: This was an error in the reference manager software. Corrected
Comment: Lines 160-161: what is water quality index?
Response: The meaning of water quality levels was provided throughout the manuscript in this new version.
Comment: Discussion: I encourage to compare your findings to results of some other, similar studies in the other parts of the world.
Response: Studies estimating maritime traffic indicators and their influence on water quality variables in space and time are limited, most of the works using traffic variable are carried out by the quantity of vessels, amount of cargo or tourists transported, and the variables studied generally include just metals and hydrocarbons
Comment: Discussion: do your results indicate that tourism-related marine traffic has serious environmental effect? Please, conceptualize and add the general literature. Look at these sources and the literature cited there: https://link.springer.com/article/10.1007/BF02241824, https://www.mdpi.com/2076-3263/10/6/242, https://www.mdpi.com/2073-4441/11/6/1265/htm
I think these and some (many!) other works can be considered and cited.
Response: References included as recommended
Comment: Why not to provide photos of the discussed area?
Response: Photos of the studied areas are not relevant to the study. If the editor requests them, they can be provided although they have little potential to contribute to the results and discussions presented
Comment: The language and some phrasing need heavy correction. Please, ask any English native-speaking colleague to help.
Response: The written language was reviewed by a professional
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript (JMSE-1160534) of Rodríguez-Grimón et al entitled "Effect of maritime traffic on water quality parameters in Santa Marta, Colombia”, constitutes the first report on the proposal of the maritime traffic indicator as a tool for evaluating the impact of naval activities on environmental quality.
The manuscript is well structured and written but the experimental design requires a thorough review as well as the presentation of the results obtained. Then, I present a series of questions and considerations for authors.
In the summary, it would be necessary to indicate to which the acronym PNNT corresponds
In the introductory section, paragraph “This approach is especially relevant in busy naval traffic areas located in coastal zones, where contaminant releases are more likely to occur”, it would be convenient to change it to “This approach is especially relevant in busy naval traffic areas located in coastal zones, where pollutant discharges are more likely to occur ”
In the materials and methods:
- An updated bibliographic citation is required to accompany this paragraph “The coastal fringe of Santa Marta is a highly dynamic zone, in which many different socioeconomic as tourism, fishing, commerce trade and carbon transport and storage activities take place”
- Delete the following sentence and its reference ” However, such activities are known to impact environment conditions [32]”, since it is indicates the study area, not the consequences of human activity in this area.
- In line 90 of materials and methods, the study area called Bahía Internacional de Santa Marta appears with the acronym BSM but in the rest of the article as well as tables and figures, it is shown as SM.
- Why did the authors take only one sampling location within the area called Sm rather than two for PNNT? This makes the statistical treatment of the data extremely difficult.
- Both study areas (SM and PNNT) are under the influence of pollution to a greater or lesser extent. Why did the authors not take an uncontaminated area as a zero reference point to compare them with the other two, and thus be able to enhance the diagnostic capacity of the Maritime Traffic Indicator?
- According to the authors, the study period covers the years 2015-2017. However, in the next paragraph “In Santa Marta, during the studied years (2014-2017), the average of pluviometry indexes in the dry season were 7.3 mm, while in the rainy reaches 72.7 mm” 2014 is mentioned. I guess she is a typo, please correct it.
- in figure 2 it would be necessary to indicate to which the IDEAM acronym corresponds.
- Did the authors test some type of mathematical transformation of the data of the variables in order to fulfill the assumptions of normality and homoscedasticity?
- Change that sentence “For all the tests, an error p < 0.05 was assumed” to this other "Statistical significance was set at P <0.05".
- In my opinion, I believe that an analysis of the correlations between the analyzed variables is lacking, since later the authors, in different sections of the article, are speculating on the relationship or correlation between different variables.
- The statistical treatment of the data was carried out with the mean values of all the data for each variable, or on the contrary, was it carried out with all the data obtained during the years 2015-2017?
In the results:
1. In the first paragraph of section 3.1 of results, the authors indicate a coliforms average (TC) of 438 MPN/100 ml in SM; however, table 1 shows an average value of 250 MPN/100 ml. Where is the error, in the text or in the table?
2. I consider it necessary to give the most detailed data in Table 1 (by year analyzed, wet and dry season), in such a way that the spatial and temporal variation of the different variables analyzed can be really seen. The variation of the data for VEc, VEe and VEt could have been included in table 1.
3. In relation to the next sentence " The number of boats docked in different 206 places of the PNNT, showed a gradual increase over the years (2015= 3150 boats, 2016= 207 3795 boats and 2017 = 3872 boats). During 2015 Concha Bay (CB) and Nenguange (Neg) 208 received 11% of the total number of boats going to PNNT and in 2017 this number 209 increased to 23% ".
According to those described by the authors, the number of boats in other areas of the PNNT park is much higher compared to the two areas chosen for this study (CB and Neg), why weren't more places analyzed in order to obtain a quantity real representative of the ships within the PNNT?
4. In relation to the next sentence “The gradual increase in boats amounts visiting PNNT presented a direct correspondence with the total number of visitors to the national park (Figure 3)”.
And what was the degree of correlation? With figure 3, I can deduce that it would not be very high, especially since the number of ships taken into account is much lower than the real one.
5. Again, figure 3 is too simple and does not give enough information. It would be necessary to break it down into years, season and place of sampling.
6. In section 3.3 of results, the authors do not give the percentage of the variability explained for the first and second components, as well as the variables with which the first component is most related.
In discussion:
- In addition, boat traffic 239 was also significantly correlated to TC and DDPH concentrations (p < 0.01) (Figure 4A). But the authors do not provide the degree of correlation (value of R) between the mentioned variables.
- The high concentrations of TC registered in SM, was related to proximity with urban zones and number of visitors. In Santa Marta, the main source of TC to coastal waters is a sewage outfall that drains wastewater generated in the city towards Santa Marta bay. It is important to highlight that previous studies have demonstrated episodes of overflow and spillage in this system during the rainy seasons [42, 52].
I don't think reference 52 is the most appropriate for the written paragraph. This reference is related to the presence of estrogens in sediments in an estuary in Brazil. The authors measure coliforms in water, not estrogens. In addition, for this paragraph the authors rely only on two citations and both in Spanish. It is necessary to carry out a bibliographic search of what could have happened in a similar way in other places, and compare them with those obtained by the authors.
- TC levels significant raised during rainy season in SM. In contrast, TC values decreased towards BC and Neg establishing a spatial and temporal contamination gradient.
However, as the authors have presented the data, it is very difficult to verify this spatial and temporal variation.
- Despite this, TC values recommended as limit for recreational use by primary and secondary contact, were never surpassed [53].
What do you mean by primary and secondary contact?
- This assertion is supported by several scientific publications reporting petroleum hydrocarbons impacts in areas under the influence of ports (commercial and fishing) and tourist marinas even in pristine areas [54].
Furthermore, the reference 54 is not appropriate, since it is not an investigative article but an order from the Colombian government. There are immense articles of research and reviews in this regard.
- Hurricanes in Atlantic Ocean are quite common phenomena between the months of June and November. Such extreme events, originated over warm waters surface, play an essential role in the ship and boat traffic in Santa Marta. The historical distribution percentages indicate Caribbean Sea (11%) and western Pacific areas (39%) with highest probability of hurricane incidence [59].
Again the reference is not related to the phrase.
- Hence, Santa Marta present a major yacht affluence during dry seasons avoiding hurricane seasons [61].
- This reference is too old since the authors intend to relate the hurricane rate between 2015-2017 with the influx of ships in the SM area. There will be no more up-to-date references.
Author Response
Comment: The manuscript (JMSE-1160534) of Rodríguez-Grimón et al entitled "Effect of maritime traffic on water quality parameters in Santa Marta, Colombia”, constitutes the first report on the proposal of the maritime traffic indicator as a tool for evaluating the impact of naval activities on environmental quality. The manuscript is well structured and written but the experimental design requires a thorough review as well as the presentation of the results obtained. Then, I present a series of questions and considerations for authors.
Response: Thank you for your comments. We appreciate the opportunity to improve the manuscript.
Comment: In the summary, it would be necessary to indicate to which the acronym PNNT corresponds
Response: The acronym PNNT was indicated in the abstract
Comment: In the introductory section, paragraph “This approach is especially relevant in busy naval traffic areas located in coastal zones, where contaminant releases are more likely to occur”, it would be convenient to change it to “This approach is especially relevant in busy naval traffic areas located in coastal zones, where pollutant discharges are more likely to occur”
Response: Corrected as recommended
In the materials and methods:
Comment: An updated bibliographic citation is required to accompany this paragraph “The coastal fringe of Santa Marta is a highly dynamic zone, in which many different socioeconomic as tourism, fishing, commerce trade and carbon transport and storage activities take place”
Response: Corrected as recommended, citation included (35).
Comment: Delete the following sentence and its reference” However, such activities are known to impact environment conditions [32]”, since it is indicates the study area, not the consequences of human activity in this area.
Response: The sentence was deleted as recommended
Comment: In line 90 of materials and methods, the study area called Bahía Internacional de Santa Marta appears with the acronym BSM but in the rest of the article as well as tables and figures, it is shown as SM.
Response: These acronyms were double cheeked throughout the manuscript. However, the is a difference. SM = International Santa Marta Marine and BSM = Santa Marta Bay
Comment: Why did the authors take only one sampling location within the area called Sm rather than two for PNNT? This makes the statistical treatment of the data extremely difficult.
Response: Contaminants reaching water bodies are spatially distributed under the influence of different oceanographic forces such as tides, coastal currents, winds, etc. In the present study, one of the main questions was whether PNNT would be affected by these variables. Thinking on that, the points distribution strategy was chosen. Also, the sampling points were dependent on the station monitored since all physicochemical and microbiological variables used in the present study were obtained from “open data” made available by Surveillance Network for the Conservation and Protection of Marine and Coastal Waters of Colombia
Comment: Both study areas (SM and PNNT) are under the influence of pollution to a greater or lesser extent. Why did the authors not take an uncontaminated area as a zero reference point to compare them with the other two, and thus be able to enhance the diagnostic capacity of the Maritime Traffic Indicator?
Response: Because the traffic and water quality monitoring data at the time of study were open data (dataset), and the "less polluted" sites have no water quality monitoring or traffic reporting.
Comment: According to the authors, the study period covers the years 2015-2017. However, in the next paragraph “In Santa Marta, during the studied years (2014-2017), the average of pluviometry indexes in the dry season were 7.3 mm, while in the rainy reaches 72.7 mm” 2014 is mentioned. I guess she is a typo, please correct it.
Response: Corrected as recommended
Comment: in figure 2 it would be necessary to indicate to which the IDEAM acronym corresponds.
Response: Corrected as recommended
Comment: Did the authors test some type of mathematical transformation of the data of the variables in order to fulfill the assumptions of normality and homoscedasticity?
Response: No data transformation was performed to fulfill normality and homoscedasticity assumptions.
Comment: Change that sentence “For all the tests, an error p < 0.05 was assumed” to this other "Statistical significance was set at P <0.05".
Response: Changed as recommended
Comment: In my opinion, I believe that an analysis of the correlations between the analyzed variables is lacking, since later the authors, in different sections of the article, are speculating on the relationship or correlation between different variables.
Response: We improved the wording in the manuscript, giving clarity to the interpretation of the PCA result.
Comment: The statistical treatment of the data was carried out with the mean values of all the data for each variable, or on the contrary, was it carried out with all the data obtained during the years 2015-2017?
Response: Statistical analysis was performed on all data obtained during the years 2015-2017.
In the results:
Comment: In the first paragraph of section 3.1 of results, the authors indicate a coliforms average (TC) of 438 MPN/100 ml in SM; however, table 1 shows an average value of 250 MPN/100 ml. Where is the error, in the text or in the table?
Response: There is no error; we proceeded to improve the visibility of results in table 1 according to the presentation of the text. 438 MPN/100 mL was the average TC concentration during the rainy season, while 250 MPN/100 mL was the annual average between 2015 - 2017.
Comment: I consider it necessary to give the most detailed data in Table 1 (by year analyzed, wet and dry season), in such a way that the spatial and temporal variation of the different variables analyzed can be really seen. The variation of the data for VEc, VEe and VEt could have been included in table 1.
Response: Changed as recommended
Comment: In relation to the next sentence "The number of boats docked in different 206 places of the PNNT, showed a gradual increase over the years (2015= 3150 boats, 2016= 207 3795 boats and 2017 = 3872 boats). During 2015 Concha Bay (CB) and Nenguange (Neg) 208 received 11% of the total number of boats going to PNNT and in 2017 this number 209 increased to 23% ". According to those described by the authors, the number of boats in other areas of the PNNT park is much higher compared to the two areas chosen for this study (CB and Neg), why weren't more places analyzed in order to obtain a quantity real representative of the ships within the PNNT?
Response: Because water quality data is only available for BC and Neg, which are the most popular sites for tourists.
Comment: In relation to the next sentence “The gradual increase in boats amounts visiting PNNT presented a direct correspondence with the total number of visitors to the national park (Figure 3)”. And what was the degree of correlation? With figure 3, I can deduce that it would not be very high, especially since the number of ships taken into account is much lower than the real one.
Response: Figure 3 was modified to show the result of the regression, which was fitted to a quadratic model and was significant (p<0.05) but not strong. The number of ships to PNNT is the total reported by the port authority, which controls maritime access to the protected area.
Comment: Again, figure 3 is too simple and does not give enough information. It would be necessary to break it down into years, season and place of sampling.
Response: Changed as recommended
Figure 3..(A) Number of boats per month visiting Santa Marta, Bahía Concha, Nenguanje between season and (B) total number of boats in relation to the number of visitors per month to the PNNT.
Comment: In section 3.3 of results, the authors do not give the percentage of the variability explained for the first and second components, as well as the variables with which the first component is most related.
Response: Inserted as recommended
In discussion:
Comment: In addition, boat traffic 239 was also significantly correlated to TC and DDPH concentrations (p < 0.01) (Figure 4A). But the authors do not provide the degree of correlation (value of R) between the mentioned variables.
Response: Traffic - TC: r = 0.741; Traffic - DDPH: r = 0.313 (inserted in the text)
Comment: The high concentrations of TC registered in SM, was related to proximity with urban zones and number of visitors. In Santa Marta, the main source of TC to coastal waters is a sewage outfall that drains wastewater generated in the city towards Santa Marta bay. It is important to highlight that previous studies have demonstrated episodes of overflow and spillage in this system during the rainy seasons [42, 52].I don't think reference 52 is the most appropriate for the written paragraph. This reference is related to the presence of estrogens in sediments in an estuary in Brazil. The authors measure coliforms in water, not estrogens. In addition, for this paragraph the authors rely only on two citations and both in Spanish. It is necessary to carry out a bibliographic search of what could have happened in a similar way in other places, and compare them with those obtained by the authors.
Response: There was a numbering error in the references, which was corrected in this new version
Comment: TC levels significant raised during rainy season in SM. In contrast, TC values decreased towards BC and Neg establishing a spatial and temporal contamination gradient.
However, as the authors have presented the data, it is very difficult to verify this spatial and temporal variation.
Response: We made the changes The table was included to clarify the temporal variation
Comment: Despite this, TC values recommended as limit for recreational use by primary and secondary contact, were never surpassed [53].What do you mean by primary and secondary contact?
Response: According to Colombian decree 1594 of 1984 for uses of water and liquid wastes
Quality water criteria used for recreational purposes are: (1) Primary contact, as in swimming and diving, including medicinal baths as (2) Secondary contact as in water sports and fishing.
The limit for primary and secondary contact are 1000 (MPN/100 mL) and 5000 (MPN/100 mL) respectively. This information was now provided.
Comment: This assertion is supported by several scientific publications reporting petroleum hydrocarbons impacts in areas under the influence of ports (commercial and fishing) and tourist marinas even in pristine areas [54]. Furthermore, the reference 54 is not appropriate, since it is not an investigative article but an order from the Colombian government. There are immense articles of research and reviews in this regard.
Response: There was a numbering error in the references, which was corrected in this new version
Comment: Hurricanes in Atlantic Ocean are quite common phenomena between the months of June and November. Such extreme events, originated over warm waters surface, play an essential role in the ship and boat traffic in Santa Marta. The historical distribution percentages indicate Caribbean Sea (11%) and western Pacific areas (39%) with highest probability of hurricane incidence [59]. Again the reference is not related to the phrase. Hence, Santa Marta present a major yacht affluence during dry seasons avoiding hurricane seasons [61]. This reference is too old since the authors intend to relate the hurricane rate between 2015-2017 with the influx of ships in the SM area. There will be no more up-to-date references.
Response: There was a numbering error in the references, which was corrected in this new version.
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors report a basic method for the estimation of the maritime traffic effect on the water quality parameters. While the general idea is promising and might be a first prognosis in terms of traffic effects, there is a lack of profound data distinguishment between urban and real marine traffic effects on the contamination. How do the authors distinguish "marine traffic sources" data from "urban inland sources" in real data aspects? This question should definitely be addressed more properly with regard to the manuscript in terms of data presentation / discussion. Besides that there should be a proper check in terms of grammar and style.
Author Response
Comment: The authors report a basic method for the estimation of the maritime traffic effect on the water quality parameters. While the general idea is promising and might be a first prognosis in terms of traffic effects, there is a lack of profound data distinguishment between urban and real marine traffic effects on the contamination.
Response: Thank you for your comments. We appreciate the opportunity to improve the manuscript.
Comment: How do the authors distinguish "marine traffic sources" data from "urban inland sources" in real data aspects? This question should definitely be addressed more properly with regard to the manuscript in terms of data presentation / discussion.
Response: Contaminants reaching water bodies are spatially distributed under the influence of different oceanographic forces such as tides, coastal currents, winds, runoff from land, etc. In the present study, one of the main questions was whether PNNT would be affected by these variables. Thinking on that, the points distribution strategy was chosen. Also, the sampling points were dependent on the station monitored since all physicochemical and microbiological variables used in the present study were obtained from “open data” made available by Surveillance Network for the Conservation and Protection of Marine and Coastal Waters of Colombia. We improved the wording in the manuscript, giving clarity to the interpretation of the results.
Comment: There should be a proper check in terms of grammar and style.
Response: The written language was reviewed by a professional
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The review made by the authors of the considerations and doubts raised by the reviewer have been answered satisfactorily. In such a way that now the research work presented by the authors to the JMSE journal can be presented for publication.
Author Response
Thank you for your comments. We appreciate the opportunity to improve the manuscript.
Reviewer 3 Report
The authors did not dramatically change the first manuscript version, respectively in view of the conclusion section the requested discussion on resu "marine traffic sources" and "urban inland sources" in real data aspects is not yet found clearly enough.
Author Response
Comment: The authors did not dramatically change the first manuscript version, respectively in view of the conclusion section the requested discussion on resu "marine traffic sources" and "urban inland sources" in real data aspects is not yet found clearly enough.
Response: From our point of view, this issue was clear in the original version of the manuscript. However, we made some changes in discussion and conclusion sections seeking to better clarify this point. Please see:
Lines 278-282: New sentences inserted > "Moreover, urban inland sources, not directly related to naval traffic, also contribute to the observed levels. Thus, it is not possible to distinguish contamination sources based on the measured concentrations. Despite this, the statistical approach used in the present study indicates the influence of marine traffic on observed variations."
Lines 283-289: Sentences that were already in the original manuscript> In Santa Marta, TC's main source of coastal waters is a sewage outfall that drains wastewater generated in the city towards Santa Marta bay. It is important to highlight that previous studies have demonstrated overflow and spillage episodes in this system during the rainy seasons [35, 55]. TC levels significantly raised during the rainy season in SM. In contrast, TC values decreased towards BC and Neg, establishing a spatial and temporal contamination gradient. In fact, this indicator of organic contamination was related to water drainage from the urban area and visitors seasonally, presenting increments during tourist seasons in the months of July and August.
Lines 352-353: Sentences that were already in the original manuscript> The high levels of TC and DDPH in SM were explained by the proximity to urban contamination sources associated with intense maritime traffic in Santa Marta bay.
lines 353-355: New sentence inserted > Although it is not possible to distinguish contributions from each source, the statistical approach showed a strong relationship between analyzed variables and naval traffic.
Author Response File: Author Response.pdf
