Microorganisms Collected from the Surface of Freshwater Lakes Using a Drone Water Sampling System (DOWSE)
, Philipp Baloh 2, Craig W. Powers 3, Hinrich Grothe 2 and David G. Schmale 1,*Round 1
Reviewer 1 Report
The manuscript submitted by Benson et al. presents the use of an UAV for sampling surface water for culture-based microbiology analyses. It is nicely written and it presents interesting results.
I have only two comments:
The Introduction should better present the importance of such an approach in comparison to "classical" sampling approaches. Why should an environmental microbiologist choose such a sampling system?
As the samples (filters) were kept for up to two weeks before cultivation, the results may not present actual cultivable diversity in the surface water of investigated lakes. This should be discussed accordingly.
Author Response
Reviewer Comments: The Introduction should better present the importance of such an approach in comparison to "classical" sampling approaches. Why should an environmental microbiologist choose such a sampling system?
Author Response. We have added additional language in the introduction to address traditional sampling methods, and importance of our approach in the context of these methods.
Reviewer Comments: As the samples (filters) were kept for up to two weeks before cultivation, the results may not present actual cultivable diversity in the surface water of investigated lakes. This should be discussed accordingly.
Response. This is an excellent point. We have added additional language to the discussion to address this, particularly in the context of the lower concentrations compared to other published work.
Reviewer 2 Report
This paper combines a drone sampling methodology for freshwaters with an analysis of freshwater bacteria on two different agars. The paper is well written, and presented.
The paper tests two hypotheses - (1) concentration of culturable microorganism in freshwater lakes would vary with distance from the shore and (2) the frequency of ice-nucleating strains of Pseudomonas spp. would vary across different freshwater lakes. However, I cannot see any background in the introduction that explains the rationale for these hypotheses. Nor do the authors do not explain why these hypotheses are of interest.
In the discussion the bacterial data is interpreted in relation to factors such as depth and different lake type, however, there is no environmental water quality data that would put this data into context, and help explain any observed patterns.
Overall beyond the sampling of water using a drone, I cannot see the novelty of the results presented, and the authors need to be clearer as to the rationale for their study and the importance of the data they collect, and questions they seek to answer with the data.
Author Response
Reviewer comments: The paper tests two hypotheses - (1) concentration of culturable microorganism in freshwater lakes would vary with distance from the shore and (2) the frequency of ice-nucleating strains of Pseudomonas spp. would vary across different freshwater lakes. However, I cannot see any background in the introduction that explains the rationale for these hypotheses. Nor do the authors do not explain why these hypotheses are of interest.
Author response: Excellent points. We have added additional language to the introduction to address the rationale and importance of our hypotheses.
Reviewer comments. In the discussion the bacterial data is interpreted in relation to factors such as depth and different lake type, however, there is no environmental water quality data that would put this data into context, and help explain any observed patterns.
Author response. Unfortunately, we did not make any additional water quality measurements, and all of our samples were filtered and plated. We have added additional language to the discussion to address the limitation in our study, and to query the possibility of these measurements in the future.
Reviewer comments: Overall beyond the sampling of water using a drone, I cannot see the novelty of the results presented, and the authors need to be clearer as to the rationale for their study and the importance of the data they collect, and questions they seek to answer with the data.
Author response. We have added additional clarity to the introduction and discussion to address the rationale behind our hypotheses and novelty of the study.
Reviewer 3 Report
Journal: Water
Title: Microorganisms collected from the surface of freshwater lakes using a drone water sampling system (DOWSE)
Manuscript ID: water-387387
In this manuscript a study on a development of a system to collect water samples from the surface of lakes using a 3D-printed sampling device tethered to a drone. This sampling system enablesthe collection and characterization of microbes without the potential of cross-contamination across samples.
Two hypotheses were at the base of this study, in one case the fact that concentrations of culturable microorganisms in freshwater lakes would vary with distance from the shore, in the other the fact that the frequency of ice-nucleating strains of Pseudomonas spp. would vary across different freshwater lakes.
Sampling were carried out by using sterile tubes tethered to a drone, the latter called DWOSE, DrOne Water Sampling SystEM. Water samples were harvested from eight lakes in Austria.
Each water sample collected from the lakes, recovered by an operator and sterile tube was substituted. Each water sample was processed by filtering and culturing microorganisms.
This manuscript shows the first report of a drone water sampling system for studying microorganisms in aquatic habitats. The novelty of the manuscript is very important. In fact, before, in unmanned serfon vehicle (USV) developed to collect microorganisms, one limitation was represented by the potential for cross-sample contamination, since the same hose was used for collecting multiple samples. Sterility is maintained and observed at each sampling site, thus conferring validity for sampling in a microbiological context. The described water sampling system has the potential to be used in a variety of hard-to-reach aquatic environments, such as high-altitude alpine lakes and ponds.
The manuscript is well written and reports a novel study where, for the first time, a drone system was used to sampling water from aquatic habitats for microbiological analyses.
Revisions:
Page 5 line 169: (Mohan and Schaad, 1987): this reference is not reported in the reference list;
Page 14 lines 417, 419: “Pseudomonas syringae” change to the Italic style;
Page 15 page 447: Gibberella zeae change to the Italic style;
Page 15 lines 454, 459: “Pseudomonas syringae” change to the Italic style;
Author Response
Page 5 line 169: (Mohan and Schaad, 1987): this reference is not reported in the reference list
Response. This reference has been added.
Page 14 lines 417, 419: “Pseudomonas syringae” change to the Italic style
Response. This is now in italics.
Page 15 page 447: Gibberella zeae change to the Italic style.
Response. This is now in italics.
Page 15 lines 454, 459: “Pseudomonas syringae” change to the Italic style.
Response. This is now in italics.
Round 2
Reviewer 2 Report
The authors have responded to my earlier concerns and have added extra text to both the introduction and the discussion. The manuscript is excellently written and is presented in a clear manner.
Author Response
Thank you.
