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

1. 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.

2. 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)

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), 

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

1. 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.

2. 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 m³   and  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.

3. 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.

4. 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”

5. 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.

5. 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

1. 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

1. 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.

2. 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)

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.

3. 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). 

3. 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.

4. 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