Review Reports - Assessing Climate and Human Activity Effects on Hypersaline Lake Ecosystem: Case Study of Saki Lake, Crimea

Round 1

Reviewer 1 Report

The manuscript addresses the climate assessment and human activity effects on hypersaline lake ecosystem for a case study of Saki Lake, Crimea.

The context for the research is clearly stated. The background and need for the research is well justified.

The paper covers a suitable research gap. So, it i recommended for publication in terms of scientific content.

The paper is well structured and well written. However, English should be proofread.

Methodology is well explained.

Results are compared with literature and there is good critical discussion within the section.

Conclusions are well justified and related to the main findings. However, future recommendations linked to main outcomes could be provided.

Some minor amendments are needed:

-Standard deviation for the results obtained are needed. Reliability of results? Reproducibility? Figure 7 to 13.

-Formatting of figures is different, so it should be consistent.

Author Response

Dear Referee,

Thank you very much for comments and recommendations, which are useful for improving of the present manuscript. They are helpful for me in my future study also.

There are the explanations of the your comments

The standard deviations were added in the Table 1 and Fig. 13. In Fig, 7 the values of precipitation are present, which were obtained in the Internet resources https://nuipogoda.ru/, thus it’s impossible to add SD.

About reliability and reproducibility of the results. The distribution of the bribe shrimp Artemia in the water body varies widely and depends on the wind, phytoplankton, depth and other factors. That’s why the results presented in Table 1 varied also and SD is high. However, we would like to demonstrate high variability of the brine shrimps concentr4ation in three reference places in the tested water body and use SD for this. As for hatching rate determination, we analyzed this parameter in laboratory condition in triplicates for every tested sample, and the obtained data were reliability.

Figures are revised, the additional data which we obtained in our field studies in December (Dec,14) were introduced in the figures. English was revised also and corrections were introduced in text/

Thank you very much for your attention tour manuscript and very useful comments.

Yours sincerely,

Prof Irina Rudneva

Author Response File: Author Response.pdf

Reviewer 2 Report

Good paper, but to improve the scientific quality, I will suggest some recommendations, and I will suggest to be accepted after minor correction

- In the title added (South of Ukraine)

- In the introduction, more explain the impact of climate change on water resources in other regions in the world (added the references of):

Y Hamed, R Hadji, B Redhaounia, K Zighmi, F Bâali, A El Gayar 2018. Climate impact on surface and groundwater in North Africa: a global synthesis of findings and recommendations. Euro-Mediterranean Journal for Environmental Integration 3 (1), 1-15

Y Hamed, M Zairi, W Ali, HB Dhia 2010. Estimation of residence times and recharge area of groundwater in the Moulares mining basin by using carbon and oxygen isotopes (South Western Tunisia). Journal of Environmental Protection 1 (04), 466

AE Gayar, Y Hamed 2017. Climate change and water resources management in Arab countries. Euro-Mediterranean Conference for Environmental Integration, 89-91

H Besser, L Dhaouadi, R Hadji, Y Hamed, H Jemmali 2021. Ecologic and economic perspectives for sustainable irrigated agriculture under arid climate conditions: An analysis based on environmental indicators for southern Tunisia. Journal of African Earth Sciences 177, 104134

- More detail the fluctuation between (lake levels and shallow aquifer levels),

- More detail the medical and economic significance of this lake

- Added a conceptual model showing the hydrodynamic of the lake and the impact of natural and the anthropogenic activities

- More detail the climate oscillations durinf 6500 and 7000 Years

- Added some recommendations

-Revise the english

Author Response

Dear Referee,

Thank you very much for comments and recommendations, which are useful for improving of the present manuscript. They are helpful for me in my future study also.

There are the explanations of the your comments

- In the title added (South of Ukraine)

I am sorry, but at present Crimea belongs to Russia, the aim of then present manuscript was to study the natural history, not heopolitics.

In the introduction, more explain the impact of climate change on water resources in other regions in the world (added the references of):

The explanations and corresponding references were added in the section Discussion and References ( red color)

AE Gayar, Y Hamed 2017. Climate change and water resources management in Arab countries. Euro-Mediterranean Conference for Environmental Integration, 89-91

- More detail the fluctuation between (lake levels and shallow aquifer levels),

We did not study the correlations between lake level and shallow aquifer levels, however in future we try to make this study

- More detail the medical and economic significance of this lake

This information was added

- Added a conceptual model showing the hydrodynamic of the lake and the impact of natural and the anthropogenic activities

- More detail the climate oscillations durinf 6500 and 7000 Years

Unfortunately, we at present study we have not this information, and it was not the aim of the present investigation

- Added some recommendations

The recommendations are present in the text: to use the artificial hydrotechnical system for the regulation of water level and salinity in the lake

-Revise the English

English was revised

Thanks a lot for the comments,

Regards,

Prof. Irina Rudneva

Author Response File: Author Response.pdf

Reviewer 3 Report

The article concerns hydrologically interesting objects that are hypersline lakes. I recommend the article for publication after referring to the following comments.

In Figure 1 it is worth showing the bathymetry of Saki lake.

How do the characteristics of the catchment affect the analyzed parameters? What is its area? How is the structure of use?

How does the year 2022 compare to a longer period of several/decades? I mean was it wet/dry, warm/cool? What relevance does this have to the results obtained?

The Discussion chapter needs a thorough rewrite-especially in the context of relating the obtained results to other studies of this type in the world.

Much of the Discussion chapter is a duplication of the Introduction chapter. This should be changed.

The conclusions about the gradual increase in air temperature and then its decrease are obvious- they do not bring any new content.

Author Response

In Fig 1. It is worth chowing the batymetry of Saki Lake

In Fig. 1 the general overview of the Saki Lake location and surroundings are present, such as Black Sea, other lakes, roads, cities, end etc., because it is important to present the main sources of natural (climate and meteorological ) and anthropogenic factors, affected Saki Lake. In more details Saki Lake and its Eastern Basin are present in Fig. 3, where the 7 water bodies, man-made hydrotechnical system with its channels, damps, and etc. are shown.

How do the characteristics of the catchment affect the analyzed parameters? What is its area? How is the structure of use?

The area of the Eastern Basin is 1.27 km², the volume of the brine is 1270 000 m³and the volume of the mud is 446700 m³. The coordinates of the location of the lake and sampling sites were determined using a Samsung Galaxy A5 smartphone (Samsung Electronics, CoLtd, South Korea). Water samples were taken at a 10-cm depth using a special device. All observations were made at the control station in the reservoir (N 45°07’24.91”, E 33°35’25.63”; WGS 84 system).

The sediments are extracted from the bottom and transported to the clinics, where hey are used for medical purposes. In the Fig. you can see the dynamics of withdrawal of peloids from the bottom of Eastern Basin of Saki Lake ( with the permission of the colleagues of Saki Hydrogeological Regime Station)

The main factors affecting the ecosystem of Eastern Basin of Saki lake and other basins are climate, meteorological and anthropogenic, which we describe in our paper.

How does the year 2022 compare to a longer period of several/decades? I mean was it wet/dry, warm/cool? What relevance does this have to the results obtained?

Of course, the meteorological parameters of the studied area fluctuated annual. For example, the average sum of precipitation is estimated as 300–400mm per year, and 2022 was not exception. However, sometimes we observed high increase of the precipitation above 700 mm ( 1997), or decrease to150 mm (1993). The evaporation of the water in Saki Lake is estimated as 800 mm/year, and in several cases it increases to 1800 mm in 2009. The lowest value was found in 1997 (630 mm).Therefore, as we see, the evaporation level is higher, than precipitation level, which caused the growth of the salinity in the brine. To protect this and save the optimal salinity the man-made hydrotechnial system was constructed. All this information was obtained from our colleagues in Saki Hydrogeological Regime Station, who monitor Saki Lake during long time. It’s a good idea to compare the long-term climate change and its influence on tested parameters (air and brine temperature, precipitation, evaporation) for understanding the main trends of salt lake ecological state modification. We will realize this in future.

The Discussion chapter needs a thorough rewrite-especially in th3e context of relating the obtained results to other studies of this type in the world.

Section “Discussion” was re-organized and the duplications were reject. The information of the dynamics of other salt lakes are added in the section “Discussion” and additional references are added in the section “References”

Much of the Discussion chapter is a duplication of the Introduction chapter. This should be changed.

The information, which was the similar as in the Introduction, was reject from Discussion section.

The conclusions about the gradual increase in air temperature and then its decrease are obviously do not bring any new content. were revised and re-organized.

Thanks a lot for the comments,

All of them are very helpful for the improving manuscript and for further study.

Sincerely,

Prof. Irina Rudneva

Author Response File: Author Response.pdf

Reviewer 4 Report

This case/field study is interesting and provides useful data for the fluctuation of hypersalinity in natural water bodies. My points of concern are as follows.

1. What are the resources for salinity changes throughout the year? Natural or anthropogenic, if anthropogenic, what are the sources?

2. How about the accuracy and precision of the measuring device used in this study.

3. It is better to mention the statistical error along with true data.

4. Fif. 10 . Few data points are not readable.

Author Response

Dear Referee,

Thank you very much for comments and recommendations, which are useful for improving of the present manuscript. They are helpful for me in my future study also.

There are the explanations of the your comments

What are the resources for salinity changes throughout the year? Natural or anthropogenic, if anthropogenic, what are the sources?

The main sources for salinity changes in Saki Lake are the following

Natural sources for salinity changes

- atmospheric precipitation,

- ground waters,

- marine water, which entering from the sea via soil barrier ( see Fig)

- man-made hydrotechnical system, where the marine water entering to the basin via the channel. It was constructed for the artificial regulation of the salinity in the Eastern Basin of Saki Lake, especially in the hot season.

The anthropogenic sources of salinity changes in Saki Lake are the following:

the freshwater from the fields and vegetables garden,
sewage from the enterprises
the extraction of the peloids from the bottom of the lake

In the Table you can see the changes of the mineralization (salinity) in the Eastern basin of the Saki Lake during 2005-2011.

Table. Seasonal fluctuations of the salinity in the Eastern Basin of Saki Lake at the period from 2005 to 2018 ( with the permission of the colleagues of Saki Hydrogeological Regime Station)

*Eastern Basin*
Year	2005	2006	2007	2008	2009	2010	2011
Brine (winter, summer)	139	134	130	135	141	133	129
Brine (winter, summer)	184	177	194	211	173	169	174
Peloid solutrion (winter, summer)	167	162	190	168	174	180	170
Peloid solutrion (winter, summer)	170	184	184	184	183	181	178
Year	2012	2013	2014	2015	2016	2017	2018
Brine (winter, summer)	133	143	146	145	151	138	145
Brine (winter, summer)	201	196	184	200	192	199	196
Peloid solution (winter, summer)	175	170	185	180	179	180	180
Peloid solution (winter, summer)	182	183	190	185	191	193	173

The data presented in the Table demonstrated the increase of salinity in summer period, which is not good for the ecosystem and especially biota. For the decrease of salinity to optimal values the marine water input ( 500 000 m³ ) and remove of the brine ( 50 000 m³)nd is necessary to obtain optimal salinity 150 g/l.

How about the accuracy and precision of the measuring device used in this study.

All equipment which we used in present study have the certificates of quality, and they are present at the web-site www.ecosolution.ru and www.ionomer.ru. All their characteristics correspond the fluctuations of tested parameters ( temperature, pH, Eh, concentration O₂, optical density, transparency, humidity and light).

It is better to mention the statistical error along with true data.

The SD was present in Table 1 and Fig. 13. In other cases in figures we determined the parameters in triplicates and the values were nod changes each from other.

Fif. 10 . Few data points are not readable.

The fig. 10 was changed.

Thank you very much for your attention tour manuscript and very useful comments.

Yours sincerely,

Prof Irina Rudneva

Author Response File: Author Response.pdf