Geostatistics and Structure from Motion Techniques for Coastal Pollution Assessment along the Policoro Coast (Southern Italy)
Round 1
Reviewer 1 Report
The paper is enhanced from the first version, but still needs some work.
1) Line 147: Specify why "whitout the influence of high or low tide"
2) Line 194: Specify the "instrumental detection limit" for each metal
3) Results and discussion: try to better comment the performed measurements, evidencing, if any, the correlations among the analytes, and among the analytes, the sampling points, the natural and human-induced inputs.
Author Response
REVIEWER 1
1) Line 147: Specify why "without the influence of high or low tide"
The reason why was specified in lines 152-154
2) Line 194: Specify the "instrumental detection limit" for each metal
The instrumental detection limit for each metal was specified in brackets, in lines 207-209
3) Results and discussion: try to better comment the performed measurements, evidencing, if any, the correlations among the analytes, and among the analytes, the sampling points, the natural and human-induced inputs.
In order to better comment the performed measurements, Table 3 and Table 4 were added and commented
Reviewer 2 Report
Caption of Figure 2 is not well aligned, as the raws 143-147.
Raw 183-185: the Authors report UNI EN ISO 11885:200 as methodology, but it refers to water quality analyses, is it the right reference? The Authors don't report the sediments sampling technique and conservation methodology.
Raw 238-239: substitue ',' with '.' as decimal separator.
Author Response
REVIEWER 2
1) Caption of Figure 2 is not well aligned, as the raws 143-147.
Captions and raws were aligned
2) Raw 183-185: the Authors report UNI EN ISO 11885:200 as methodology, but it refers to water quality analyses, is it the right reference? The Authors don't report the sediments sampling technique and conservation methodology.
The methodology UNI EN ISO 11885:2009 has been removed. The correct methodology is D.M. 13/9/99 n° 248 21/10/99 already included in the text.
The sampling technique and conservation methodology was specified.
3) Raw 238-239: substitute ',' with '.' as decimal separator.
The substitution was made
Reviewer 3 Report
Although the manuscript has been improved, there is still a lack of consistency in the Results and Discussion section.
Figures 6 to 9 are redundant.
Figure 10 has to be explained and related to the results obtained.
Table 3 has to be deeply described and explained.
The applicability of the research has to be highlighted.
Line 60 to 62 has to be rewritten in two sentences.
Section 1.1 and 1.2 could be shortened.
Author Response
REVIEWER 3
1) Figures 6 to 9 are redundant.
Figures 6 to 8 were canceled.
2) Figure 10 has to be explained and related to the results obtained.
Explanation was added in lines 258-264
3) Table 3 has to be deeply described and explained.
Table 3 (now Table 5) was described and explained in lines 269-275
4) The applicability of the research has to be highlighted.
Since this was a preliminar study to test this methodology, the applicability has to be evaluated (lines 292-295)
5) Line 60 to 62 has to be rewritten in two sentences.
Lines were rewritten in two sentences (63-66)
6) Section 1.1 and 1.2 could be shortened.
We’d prefer to not shorten section 1.1, because we were asked to specify the production activities in the area and their influence on the environment. Section 1.2 was shortened, the names of the species were probably superfluous and were canceled.
Round 2
Reviewer 3 Report
Line 87. There is no need to describe the flora and fauna in so many details in the manuscript since the aim of the study is to apply geostatistical methods. Moreover, the names of the species are not properly written. They must be italics.
English needs to be improved.
Line 217. The information provides in Table 2 is repeated in the text and the Figure 6.
Line 218. Is statistically significant the correlation performed? Which is the significance level? Which one is the statistical programmed and version used?This information must be included en Material and Methods.
Line 254. The amount of heavy metal concentration by sampling point provides the information you are looking for, it is, the distribution of pollution, and the identification of more pollution areas...so what it the advance of the method? Is it possible to predict the pollution level in a random point between samples? This would be a powerful tool.
Although the Results and Discussion are improved this section is still not well-argued.
Author Response
Line 87. There is no need to describe the flora and fauna in so many details in the manuscript since the aim of the study is to apply geostatistical methods. Moreover, the names of the species are not properly written. They must be italics.
English needs to be improved.
The paragraph was shortened.
Line 217. The information provides in Table 2 is repeated in the text and the Figure 6.
Table 2 was deleted.
Line 218. Is statistically significant the correlation performed? Which is the significance level? Which one is the statistical programmed and version used?This information must be included en Material and Methods.
Answers were added in lines 194-195 and 223-227
Line 254. The amount of heavy metal concentration by sampling point provides the information you are looking for, it is, the distribution of pollution, and the identification of more pollution areas...so what it the advance of the method? Is it possible to predict the pollution level in a random point between samples? This would be a powerful tool.
Answered in Results and Discussion (262-265)
Although the Results and Discussion are improved this section is still not well-argued.
Results and Discussion section was improved (262-265)
Round 3
Reviewer 3 Report
The manuscript has been improved.
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
Broad comments:
According to Scopus, no recent papers about the studied area (Policoro) were published, so the paper can be defined “original and interesting” for the zone, but not for the investigation methods, that are widely used in environmental assessment both together and alone.
Clear enough is the geostatistics part.
The presence of only one sample for each sampling station gives the environmental status at the sampling time, but doesn’t provide any information about the evolution of the studied parameters, so this paper should be intended as a “preliminary report” or as a “feasibility test”.
The description of the experiment is quite well detailed for what concerns the UAV (although the flight dates and times are missing), while no information is given about the analytical methods used for sand samples, and in particular about their detection limits.
Specific comments:
Add some informations about land and sea uses of the studied zone and its nearbys, so to evidence possible anthropic influences both on the litoral morphology and on the presence and tipology of pollutants (e.g. rivers, piers, industries…) Add some informations about winds and sea currents Figure 2 should be preceeded by a map of Italy, to better understand where Policoro is Add flight dates and times, specifying the presence of low or high tides and related variations in emerged land Add a description of the analytical methods, their sensitivity and limitations Figure 8 should use a Y axis scale better enabling to understand the concentrations of all metals and show their correlations (if any) Try to better specify the “human activities” (line 175)
Reviewer 2 Report
General comments
This manuscript reports a method to represent the distribution of heavy metals in a marine coastal area. The innovation is the application of new measurement platforms, such as UAV, to environmental studies, specifically to support the sampling strategy.
However the innovation level and the method that supports innovation are not well explained. Some elements are missing, especially the aspects that clarify the importance and the degree of innovation of the work.
More generally the paper reports a methodological work more than an "environmental" analysis. Indeed, it is not clear how the contamination of a small portion of the protected area can be representative of an environmental impact as there is no information on the biotic component and on the health of the ecosystem. The only environmental component taken into consideration in choosing the sampling points is in fact the detailed geomorphology.
Moreover the Authors propose a 'technique for coastal pollution modelling', but the results report the representation of a distribution not a model.
Specific comments
Abstract
The abstract reports a specific objective 'to assess the health of the coastal environment in a natural protected area in Policoro' which is not described in the manuscript.
The main innovation of the work is the orthophoto and data processing techniques for the identification of sampling points, but it is not fully described in the manuscript.
Introduction
The introduction needs an explanation on why Authors study the Policoro area and analyse metals to assess the health of this environment without taking into account the biotic component of the protected area.
The Authors talk at length about geostatistical techniques while they don't describe SfM one or how the environmental health can be affected by contaminants.
The statistical method (IDW and Spline) is reported in the introduction but it is not deepened in materials and methods also taking into account the interpolation error analysis .
The geological and sedimentological characteristics of the study area are well described, while the biotic components is omitted. Moreover give an explanation of hoe the small sampling area can be representative of the entire Policoro protected area.
Materials and Methods
Technical characteristics of the AUV and the payload is required; it was used as the method to identify sampling areas but there is no theoretical comparison with any other method.
The analytical methods used for the chemical analysis and the confidence interval of the analyses carried out are missing. There is a long description of heavy metals analyses results but no specification of how these results can be useful for the main objective of the work. No mention to the potential origin of these contaminants and their effect on the ecosystem.
A more detailed description of how the geostatistical method was applied and the related error analysis is required. A description or a representation of how 395 images produced by AUV were used for the scope and how SfM technique was applied.
In conclusion, instead of detailing the methodological approach and the technological innovation, the Authors assumed that 8 measures chosen through a method to be tested (there is no methodological comparison) in a small area are sufficient to analyse the state of health of the environment without any comparison with the state of health of the protected area biotic component.
I suggest to adjust the manuscript in a methodological point of view, highlighting how the use of the AUV can represent an innovation and an advantage compared to traditional methods (statistical, geographical and/or ecological) to plan a sampling strategy.
Figure 2 very low resolution; it doesn't report the extension of the protected area
Figure 3 very low resolution, the sampling point IDs are not clearly visible
Raw 18 chose a more correct term for 'model'
Raw 24 add a citation for pollution definition
Raw 53 a more appropriate reference for both the interpolation techniques
Raw 62 Specify: the area is protected for the presence of what?
Raw 88 more details about the technical characteristics of platform and instruments used for the study
Raw 114 specify and add reference for sampling technique, conservation and analyses.
Raw 119 specify the reason for the choice of these elements: are they connected with particular dynamic process or influence on some habitat or species. Do you have evidence of their presence from previous studies or from known sources (natural or anthropic)?
Reviewer 3 Report
Modeling environmental data is a fundamental step to understand environmental variability. Thus, this kind of study is of great interest; nevertheless, this manuscript has to be deeply improved before to be accepted. There are some suggestions to further improve the quality of the manuscript:
Introduction:
Line 32-34 Rewritten to harmonize the text
Line 45. Reference is needed
Line 51. Reference is needed
Line 59. The aim of the study has to be explained. It is necessary to highlight the novelty of the work, what other researches have done and its contribution to the field.
Line 85. Further details of the geostatistical techniques are needed.
Material and methods:
Line 119. The methods used to determine the concentration are missing. The reference of the method for each element is needed.
Results and Discussion:
Line 127. The information provide in Table 2 is repeated in the text and the Figures. The model distribution and the asses of the environment are not either explained or discussed. The applicability of this study is missing.
