Meteorological and Limnological Precursors to Cyanobacterial Blooms in Seneca and Owasco Lakes, New York, USA

Round 1

Reviewer 1 Report

This study analyzes the role of meteorological and water quality conditions in two lakes, in order to understand their effects in promoting cyanobacteria blooms. The manuscript includes a large dataset and it is properly written. However, the methods of data analysis and their presentation should be improved.

In order to understand if a specific range of values of wind speed, rainfall, temperature and light intensity can favor Cyanobacterial blooms, the authors should consider a normalized frequency of occurrence of these events (i.e. ratio between bloom and no bloom counts for each interval of these meteorological parameters), rather than their total counts (as shown in the Figures 4, 5, 6, 7). It is evident that weak winds, no rain and an intermediate temperature are the most common conditions observed in these lakes and, as a consequence, both bloom and no bloom counts are the highest ones during these meteorological conditions. However, only a variation in the relative frequency of occurrence of the blooms compared to no bloom cases can prove an enhancing effect of a specific meteorological forcing. The Conclusions of the study should be also revised accordingly to the analysis of the frequency of occurrence of the blooms.

There are also other typographic issues that can be improved by the editing of the manuscript:

In the text of the manuscript, the references are indicated both in Arabic and Roman numerals. The typographic rules of WATER indicate that the references have to be identified only with Arabic numerals.

At the end of the captions of several Figures (2, 4, 5, 6, 8, 9, 10, 13) there are two dots “. .” instead that one.

Tables: The main text of the manuscript contains tables that are not essential for this study. Table 2 (data recovery and completeness) might be moved in an Appendix, maintaining in the body of the manuscript only its overall explanation. Table 3 (data statistics) is quite large and difficult to read: it might be also showed in an Appendix and discussed in the text.

Figure 2. This figure does not show the linear interpolation of water temperature in Seneca Lake (Panel b), which is mentioned at the lines 139-141. Moreover, it is not easy to understand the relationship between Cyanobacterial blooms and water temperature in this figure, as it shows only an overall interval of years in which the blooms have occurred.

Lines 141-142: Please, explain better this sentence: “At the start of the season, CyanoHABs sightings occurred a few weeks after maximum surface water temperatures exceeding 25°C.” Looking at the Figure 2, it seems that the water temperature exceeds 25°C frequently in the Seneca Lake, but almost never in the Owasco Lake.

Figure 3e: I suppose that this panel shows bloom count data from 7:00 AM to 6:00 PM.

Figure 4a,b: Please, correct the titles of X-axes “Water temperature (°C)“.

Figures 4, 5, 6, 7: as previously mentioned, in order to detect if specific environmental conditions can enhance these blooms, the authors should clearly show also the frequency of occurrence of the blooms for each meteorological parameter (i.e. ratio between bloom and no bloom counts), together to the total number of bloom and no bloom cases. For the Figure 5, it is evident that periods with a weak wind are the most frequent ones and that the number of bloom and no bloom counts are the highest ones during calm weather conditions. Similarly, this frequency of occurrence should be calculated also for the other environmental parameters (rainfall, temperature and light intensity).

Comments for author File: Comments.pdf

The quality of the English is fine.

Author Response

In order to understand if a specific range of values of wind speed, rainfall, temperature and light intensity can favor Cyanobacterial blooms, the authors should consider a normalized frequency of occurrence of these events (i.e. ratio between bloom and no bloom counts for each interval of these meteorological parameters), rather than their total counts (as shown in the Figures 4, 5, 6, 7). It is evident that weak winds, no rain and an intermediate temperature are the most common conditions observed in these lakes and, as a consequence, both bloom and no bloom counts are the highest ones during these meteorological conditions. However, only a variation in the relative frequency of occurrence of the blooms compared to no bloom cases can prove an enhancing effect of a specific meteorological forcing. The Conclusions of the study should be also revised accordingly to the analysis of the frequency of occurrence of the blooms.

Bloom / No Bloom ratio plots are included for water temperature, wind speed, solar intensity and air temperature in the appropriate figures, figure captions, and discussed in the text (lines: 184, 193-197, 200-201, 209-210, 217-218.  We did not calculate bloom / no bloom ratios for wind direction nor rainfall, as these were different types of plots. 

There are also other typographic issues that can be improved by the editing of the manuscript:

In the text of the manuscript, the references are indicated both in Arabic and Roman numerals. The typographic rules of WATER indicate that the references have to be identified only with Arabic numerals.

Fixed.

At the end of the captions of several Figures (2, 4, 5, 6, 8, 9, 10, 13) there are two dots “. .” instead that one.

Fixed. 

Tables: The main text of the manuscript contains tables that are not essential for this study. Table 2 (data recovery and completeness) might be moved in an Appendix, maintaining in the body of the manuscript only its overall explanation. Table 3 (data statistics) is quite large and difficult to read: it might be also showed in an Appendix and discussed in the text.

We moved Table 2 and 3 to supplementary materials.  We also split Table 3 into two tables, blooms detection, and data means, standard deviations and maximum values for easier readability. 

Figure 2. This figure does not show the linear interpolation of water temperature in Seneca Lake (Panel b), which is mentioned at the lines 139-141. Moreover, it is not easy to understand the relationship between Cyanobacterial blooms and water temperature in this figure, as it shows only an overall interval of years in which the blooms have occurred.

The width of the best fit trend lines was increased for better visibility. 

Lines 141-142: Please, explain better this sentence: “At the start of the season, CyanoHABs sightings occurred a few weeks after maximum surface water temperatures exceeding 25°C.” Looking at the Figure 2, it seems that the water temperature exceeds 25°C frequently in the Seneca Lake, but almost never in the Owasco Lake.

This sentence was reworked and moved as it is more appropriate later in the text, where an example HABs season temperature plot shows the first blooms of the season after the peak in summer warmth (see Fig. 11 & line 263). 

Figure 3e: I suppose that this panel shows bloom count data from 7:00 AM to 6:00 PM.

Correct.  Figure caption modified as indicated. 

Figure 4a,b: Please, correct the titles of X-axes “Water temperature (°C)“.

Fixed.

Figures 4, 5, 6, 7: as previously mentioned, in order to detect if specific environmental conditions can enhance these blooms, the authors should clearly show also the frequency of occurrence of the blooms for each meteorological parameter (i.e. ratio between bloom and no bloom counts), together to the total number of bloom and no bloom cases. For the Figure 5, it is evident that periods with a weak wind are the most frequent ones and that the number of bloom and no bloom counts are the highest ones during calm weather conditions. Similarly, this frequency of occurrence should be calculated also for the other environmental parameters (rainfall, temperature and light intensity).

Done – See comments above. 

Author Response File: Author Response.docx

Reviewer 2 Report

The reviewed paper dedicated the investigation of conditions of CyanoHABs origination. It is an important topic in conditions of global climatic warming. The authors analyzed the results of 4-years detailed studies. Meteorological and limnological data were collected using the appropriate methodology. The manuscript is well illustrated. The conclusions are supported by data. The authors studied the modern literature on the topic of study.

I can recommend the MS for publication after the minor revision.

Suggestions to authors

1.      In the last paragraph of Introduction necessary to write the aim of the study.

2.      What was the species composition of cyanobacteria in the studied CyanoHABs? Please, insert information about it into Introduction (if you did not study this matter) or Results and Discussion (if you have got it yourself).

3.      Line 110: correct Results & Discussion to Results and Discussion

4.      Please, correct the number of references to Arabic (see Water template).

5.      Modify the Tables 1, 2 and 3 according to journal requirements.

6.      Please, transfer Table 3 to Supplementary material, it is too large.

7.      Please, enlarge Figures 2-7, 12.

 

8.      Improve the visibility of labels on Figure 14, especially in its upper part.

Author Response

1. In the last paragraph of Introduction necessary to write the aim of the study.

The aim of the study was already included in the first sentence of this last paragraph.  Line 56 was modified to emphasize our aim more completely. 

2. What was the species composition of cyanobacteria in the studied CyanoHABs? Please, insert information about it into Introduction (if you did not study this matter) or Results and Discussion (if you have got it yourself).

A paragraph with phytoplankton composition was included in the results section.  Lines 142-155.

3. Line 110: correct Results & Discussion to Results and Discussion

Fixed.  Line 113.

4. Please, correct the number of references to Arabic (see Water template).

Fixed. 

5. Modify the Tables 1, 2 and 3 according to journal requirements.

Fixed. 

6. Please, transfer Table 3 to Supplementary material, it is too large.

Tables 2 and 3 were moved to the supplementary materials as requested by Reviewr 1. 

7. Please, enlarge Figures 2-7, 12.

 Figures were enlarged. 

8. Improve the visibility of labels on Figure 14, especially in its upper part.

Font enlarged, and a few labels moved to the side of their column with tag lines. 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have revised the manuscript according to my comments and, for this reason, I suggest its publication in the present version.

Only one typographical error remains to be corrected: in the Table S3 the correct symbol (plus/minus) changed in (question mark).