Changes in Functional Response of Soil Microbial Community along Chronosequence of Spontaneous Succession on Post Mining Forest Sites Evaluated by Biolog and SIR Methods

Round 1

Reviewer 1 Report

In this study, shifts in functional activity of soil microbial communities along a chronosequence on post mining forest sites were assessed using two common approaches - BIOLOG and SIR. Unreclaimed post-mining sites seem to be an interesting object in order to research soil formation and ecosystem functions recovery. Comparing two methods indicating potential microbial activity is also an important task.

The study was done very well in terms of experiment design and providing correct conditions for microbial activity measurements. The results obtained are relevant for the development of approaches to the evaluation of microbial activity. However, currently it is not very clear from the abstract and introduction parts, what was exactly the goal of the authors? Did authors compare two methods, or did they study the microbial response using these methods? Why is it important to compare mentioned methods? The lead line of the article should be therefore written more clearly. Also, there are some unclear statements in the article, and the authors have to read the article again and correct the language. Finally, it is necessary to revise the Abstract and Introduction as well as make some adjustments and remove some speculations from the Discussion.

Abstract:

P.1.L.16 – «Microbial catabolic activity is an important characteristic of soil ecosystems». The first sentence is very general and does not reflect the subject matter of the article itself. I guess, it should describe the problems of soil formation and ecosystem restoration in post-mining sites rather than microbial catabolic activity somewhere.

P.1.L.20-22 Information on the number of substrates is redundant in abstract and should be removed.

P.1.L.30-31 «Both methods 30 revealed microbial community change along the chronosequence» - this sentence is meaningless. What changes were observed? And what has been changed?

P.1.L.32-34. The last sentence is unclear and obscure. I suggest removing it from the abstract.

Introduction:

P.2.L.57-60. This information is not needed in Introduction.

In general, you have not to write about the number of substrates used or how to add microorganisms or soil suspension into the well in Introduction part. Here, two major points should be mentioned: 1) the importance microbial activity as a soil parameter indicating shifts in ecosystem functioning; 2) despite the active spread of molecular methods based on soil DNA and RNA analysis, it is still necessary to measure the real activity (active or potential) of the processes when studying soil processes or ecosystem functions recovery.

P.2.L.62-64. “Although two methods detect different microbial community response, variation of the microbial catabolic profile in chronosequence would detect in two methods” - not clear. Please rewrite.

P.2. L.65. This paragraph appears inconsistently. You need to make a bridge from methods to the description of soil characteristics in chronosequences. Moreover, are any results on shifts in microbial community structure or other microbial activity parameters with succession in post-mining-like ecosystems?

P.2.L.72-74. “We tested the hypothesis that using microbial catabolic activity profiles obtained with Biolog and SIR methods during succession microbial activity will increase and the catabolic profile will become more diverse.” – not clear. Please rewrite.

P.2.L.74-76. “We also expect the community will become more adapted to utilize more complex resources and the proportion of cultivable bacteria in community will decrease.” - Where will it be more adapted?

Discussion:

When comparing your results on community level physiological profiling with the data obtained in previous studies please mention whether a storage of soil samples and the further incubation conditions were the same or not. I guess it should be mentioned that the way of storing soil samples before an analysis and incubation conditions during an analysis might significantly affect the results when you determine microbial activity.

P.9.L.298-299 “Microbial catabolic profile would change following soil biological and  physicochemical changes in chronosequence of post-mining site.” – not clear what it means. Please rewrite.

Author Response

In this study, shifts in functional activity of soil microbial communities along a chronosequence on post mining forest sites were assessed using two common approaches - BIOLOG and SIR. Unreclaimed post-mining sites seem to be an interesting object in order to research soil formation and ecosystem functions recovery. Comparing two methods indicating potential microbial activity is also an important task.

The study was done very well in terms of experiment design and providing correct conditions for microbial activity measurements. The results obtained are relevant for the development of approaches to the evaluation of microbial activity. However, currently it is not very clear from the abstract and introduction parts, what was exactly the goal of the authors? Did authors compare two methods, or did they study the microbial response using these methods? Why is it important to compare mentioned methods? The lead line of the article should be therefore written more clearly. Also, there are some unclear statements in the article, and the authors have to read the article again and correct the language. Finally, it is necessary to revise the Abstract and Introduction as well as make some adjustments and remove some speculations from the Discussion.

Reply to the reviewer

Thank you for your significant comments and beneficial suggestion. We revised our MS following your suggestion.

First of all, goal of this study is understanding microbial response along chronosequence. But also, we would like to compare two methods, Biolog and SIR. Because these two methods detect different microbial response. We correct the MS following your suggestion, goal of the study become clear.

Abstract:

P.1.L.16 – «Microbial catabolic activity is an important characteristic of soil ecosystems». The first sentence is very general and does not reflect the subject matter of the article itself. I guess, it should describe the problems of soil formation and ecosystem restoration in post-mining sites rather than microbial catabolic activity somewhere.

Reply to the reviewer

We change this sentence as your suggestion.

P.1.L.20-22 Information on the number of substrates is redundant in abstract and should be removed.

Reply to the reviewer

As your suggestion, we removed the number.

P.1.L.30-31 «Both methods 30 revealed microbial community change along the chronosequence» - this sentence is meaningless. What changes were observed? And what has been changed?

Reply to the reviewer

We changed “microbial community” to “microbial catabolic profile”.

P.1.L.32-34. The last sentence is unclear and obscure. I suggest removing it from the abstract.

Reply to the reviewer

As your suggestion, we removed the last sentence.

Introduction:

P.2.L.57-60. This information is not needed in Introduction.

In general, you have not to write about the number of substrates used or how to add microorganisms or soil suspension into the well in Introduction part. Here, two major points should be mentioned: 1) the importance microbial activity as a soil parameter indicating shifts in ecosystem functioning; 2) despite the active spread of molecular methods based on soil DNA and RNA analysis, it is still necessary to measure the real activity (active or potential) of the processes when studying soil processes or ecosystem functions recovery.

Reply to the reviewer

As your suggestion, we removed the last sentence. And we add the following sentence in the end of first paragraph. “Despite molecular methods based on soil DNA analysis are useful for understanding gene profile, it is still necessary to measure the real microbial catabolic activity in soil processes and ecosystem functions recovery.”

P.2.L.62-64. “Although two methods detect different microbial community response, variation of the microbial catabolic profile in chronosequence would detect in two methods” - not clear. Please rewrite.

Reply to the reviewer

We changed the sentence.

P.2. L.65. This paragraph appears inconsistently. You need to make a bridge from methods to the description of soil characteristics in chronosequences. Moreover, are any results on shifts in microbial community structure or other microbial activity parameters with succession in post-mining-like ecosystems?

Reply to the reviewer

We add the following sentence “Microbial catabolic profile would change in soil process.”

P.2.L.72-74. “We tested the hypothesis that using microbial catabolic activity profiles obtained with Biolog and SIR methods during succession microbial activity will increase and the catabolic profile will become more diverse.” – not clear. Please rewrite.

Reply to the reviewer

We rewrite this sentence.

P.2.L.74-76. “We also expect the community will become more adapted to utilize more complex resources and the proportion of cultivable bacteria in community will decrease.” - Where will it be more adapted?

Reply to the reviewer

We add following phrase “than easily decomposing substrate” in the sentence.

Discussion:

When comparing your results on community level physiological profiling with the data obtained in previous studies please mention whether a storage of soil samples and the further incubation conditions were the same or not. I guess it should be mentioned that the way of storing soil samples before an analysis and incubation conditions during an analysis might significantly affect the results when you determine microbial activity.

Reply to the reviewer

This is the first study for understanding microbial catabolic profile, so we cannot compare storing way and incubation conditions.

P.9.L.298-299 “Microbial catabolic profile would change following soil biological and  physicochemical changes in chronosequence of post-mining site.” – not clear what it means. Please rewrite.

Reply to the reviewer

We rewrite this sentence.

Reviewer 2 Report

The manuscript entitled "Changes in functional response of soil microbial
community along chronosequence of spontaneous
 succession on post mining forest sites' present important and useful information on mining site restoration.

The abstract: 

To check for:

...the important drivers were same.

Sampling: 95 Soils were sampled from the top 0 to 5 cm of soil. The soil samples were passed through a 2-mm
96 sieve and stored at 4°C. 

How many samples were collected. please, indicate this.

Author Response

The abstract:

To check for:

...the important drivers were same.

Sampling: 95 Soils were sampled from the top 0 to 5 cm of soil. The soil samples were passed through a 2-mm

96 sieve and stored at 4°C.

How many samples were collected. please, indicate this.

Reply to reviewer

  We deleted this sentence.