Effects of Warming on Aquatic Snails and Periphyton in Freshwater Ecosystems with and without Predation by Common Carp

Round 1

Reviewer 1 Report

This MS is interesting, the main concept is correct. This what should be changed is that warming and predation couldn’t be treated similarly. There were two experiments/treatments in which fish was present; one at environmental temperature, and the second at increased temperature, i.e. warming conditions. So, increased predation could be result of warming, but this is just an variable influenced by warming. In both treatmnets we have predation (or fish feeding with snails). In other two treatments fish was not present. So, these two different systems (with fish and without fish at different temperatures should be compared separately – C and W, and separately F and WF.

Title

Having in mind mention above, title is confusion and should be changed. Some suggestions:

¾    The influence of warming on fish-snail-periphyton interactions in shallow ecosystems (this is not completely correct, as you had two different groups of treatments)

¾    The influence of warming on the benthic composition in shallow ecosystems

Abstract

Should be corrected according to the comments above and bellow

Introduction

Lines 76-82: Should be written clearly, in line with the main comment.

Materials and Methods

Line 88: B. aeruginosa - providing food for some fish (e.g, black carp, Mylopharyngodon piceus) – do we have the evidence for common carp?

Lines 108-109. “Both snail species recovered from the collected sediments and no differences in the initial biomass and density were found for the snails in different treatments.”- What was the initial density?? It should be written here?

Lines 114-116: Treatment F and WF. This should be clearly written. As I understood: W treatment is also “predation treatment” (i.e. treatment when fish is present; what I would prefer) at “normal temperatures, while treatment WF “predation treatment” is the treatment when fish is present at increased temperature. - All treatments should be clearly explained. There were two treatment without fish, one at environmental temperature and one at increased temperature; and then two treatments where fish is added, one at environmental and one at increased temperature…

So, this is the most important part that shows direction of this paper. In the contest of the title – it is only warming effect. Predation is something that is normal when carp is present in the system, and it is just another variable that is changed by warming. For this reason, I suggest to include predation just as one variable that will differ depending on the temperature conditions.

Line 122: carps (not carp)

Line 130-131: spec-130 spectrophotometric analysis WERE (not “was”)

Lines: 158 and further – when explaining the treatment, add the treatment abbreviation.

Line 167 and further: exclude “carp predation” written on this way. In the experiments with carp, situation changed, but as an effect of the temperature (warming). Carp is just feeding with different amount of feed, what is dependent on the temperature. And you should clearly explain the effect of the warming in two different systems: with fish (F and WF) and without fish (C and W). This means that comparing four systems you are making confusion.

Lines: 188-195- this should be clearly written together with corrected English, having in mind previous comments. Briefly explain results of each system (two treatments) including comparison two comparable systems.

Lines: 229 – 231: Again, warming temperature and carp predation. It couldn’t be “warming and carp predation”, but could be that predation was higher at increased warming conditions (you have predation at environmental temperature and at environmental temperature). This should be corrected in the whole manuscript. In discussion and conclusions, as well. Example – lines 298 and 318…

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Warming and predation by common carp reduce snail popula-2 tions and increase the growth of periphyton: A mesocosm study

Cheng et al.

I have reviewed the revised manuscript “Warming and predation by common carp reduce snail popula-2 tions and increase the growth of periphyton: A mesocosm study” by Cheng et al., which looks at two species of snail feeding on the periphyton community in a mesocosm, with addition pressures by fish preadtors and warming. I think this paper is really interesting, clearly written, and easy to follow.

Please find my specific comments in the pdf. My general recommendations on this version are as follows:

1.      I think you could include a little more information on the predator. Comments in the pdf.

2.      I’m troubled that there seems to be no literature on snail predation and feeding, are you sure about that? It’s not my expertise and I can’t recommend any papers off-hand, but would suggest you check the American and European literature if you haven’t already.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf