A Ten-Year Record Shows Warming Inside the Belize Barrier Reef Lagoon

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper reports temperatures taken at multiple shallow depths at Wee-Wee Cay in Belize between 2004 and 2014 and compares them with temperatures obtained in Carrie Bow Cay. It concludes that temperatures were rising during this period, and that thermal regimes in Belize may differ from those of the rest of the Caribbean.

Temperature data taken close to coral reefs are valuable, particularly if they span long periods of time and they are taken below the sea surface.  The article is clearly written (except for two sections) and involves an exhaustive analysis of the data.  I recommend that it is published after some revision.

Specific comments:

This is an article about temperatures.  Temperatures are directly related to coral bleaching, and the discussion about these organisms is relevant and well-put. It is less clear why the section about endemic and threatened fishes has been included.  For one thing, it is doubtful that the slight increases of temperatures affect the listed species of fish, and for another this is one of the two sections in which expression could be improved.  I recommend that this section is removed, because the paper will not suffer from such shortening. After all, a ten page article based on a single series of temperature observations may be too much.

The second section that needs attention is the one labeled “3.4.  Mean monthly temperatures”.  These data are worth showing, but the text does nothing but repeat in a confusing way what readers can see more clearly in the Table.

I would also recommend that the x axis labeling of Fig. 4 be modified.  The dates marking the tick marks are written in the American way, with the month preceding the day, and the year following the day.  For the rest of the world this convention makes no sense, and (because all dates are less than12) it will be difficult even for Americans to ascertain which system is being used.  I suggest that a letter is substituted for the month and that the year is placed below.

Finally, the availability of these data (upon request from the authors) if not sufficient in these days of FAIR data accessibility. They should be placed in Dryad or another public database, where they will outlive the carriers of the authors and maybe even be updated.

Comments on the Quality of English Language

Fine

Author Response

We thank the reviewers for their helpful comments. As the reviewers note, this is not a comprehensive study by any means. It was a pilot project that was conducted just to track water temperatures at our study site at WWC. Of course, after 10 years we identified the warming trend. The purpose of this paper is to document this occurrence. We did follow the suggestion by one reviewer to include satellite data. We had previously explored this; but could not obtain it. However, NOAA’s new website allows free downloads and were able to compare the satellite data with our logger data. This took us some extra time and we are sorry for the delay over the holidays in getting the revision resubmitted sooner.

The hope is that future researchers will tackle this kind monitoring more comprehensively with an emphasis on obtaining comparable data from temperature loggers at the same depth over a much wider geographic area. . 

Specific comments:

This is an article about temperatures.  Temperatures are directly related to coral bleaching, and the discussion about these organisms is relevant and well-put. It is less clear why the section about endemic and threatened fishes has been included.  For one thing, it is doubtful that the slight increases of temperatures affect the listed species of fish, and for another this is one of the two sections in which expression could be improved.  I recommend that this section is removed, because the paper will not suffer from such shortening. After all, a ten page article based on a single series of temperature observations may be too much.

We wrote in the discussion, “Overall, much more is known about the thermal tolerances of coral species than for fishes.” The purpose of this section is to draw attention to the fact that most studies only talk about corals being impacted by warming. The impact of temperature on fishes has only been discussed for one fish in Belize; see references [21,22]. The point here is that these fishes are confined to the MBR and Bay of Honduras region and if temperature CONTINUES to increase, these fish species are at risk. The definition of endemic means that they are not found elsewhere so conditions inside the lagoon are of concern to not just corals.

The second section that needs attention is the one labeled “3.4.  Mean monthly temperatures”.  These data are worth showing, but the text does nothing but repeat in a confusing way what readers can see more clearly in the Table. 

This is the results section and we need to have text summarizing the data shown in the table.  We are not sure what the reviewer is suggesting in terms of confusing text??? It simply states the facts as shown in the Table, which needs to be referred to in the text.

I would also recommend that the x axis labeling of Fig. 4 be modified.  The dates marking the tick marks are written in the American way, with the month preceding the day, and the year following the day.  For the rest of the world this convention makes no sense, and (because all dates are less than12) it will be difficult even for Americans to ascertain which system is being used.  I suggest that a letter is substituted for the month and that the year is placed below.

We have changed the figure 4 caption as suggested

Finally, the availability of these data (upon request from the authors) if not sufficient in these days of FAIR data accessibility. They should be placed in Dryad or another public database, where they will outlive the carriers of the authors and maybe even be updated.

We have added the data as a supplemental Table S1 in excel spreadsheet format so that anyone can access.

 

Reviewer 2 Report

Comments and Suggestions for Authors

A Ten-Year record shows increased warming inside the Mesoamerican Barrier Reef Lagoon, Belize.

Review

This paper takes a very basic data set of one location over a 10 year period and highlights how changes can be observed. This is useful as a building block to more sophisticated studies but I do encourage the authors to integrate more factors to the study such as wind and rain long term changes if possible. My comments are minor in this respect.

 

Line 59 is there a picture of the loggers? Can the logger location be shown on the figure 2?

Line 70 ‘in blue’ refers to which figure?  

Line 70 Also four loggers are mentioned at various depths , why were not these loggers left for longer?

Figures 4 & 5 linear regressions of the long term data are not entirely useful. Small changes are masked and outliers have disproportionately influenced the slope. A more sophisticated approach is really required here where by some data is removed and the trend is modelled with prediction as the key mechanism to evaluation.  Showing the variance is always useful here too. The subsequent sections that show the days exceeding a threshold such as degree-heating-weeks is better, especially if the paper is about the biological impact.

Table 4. why does the SST comparison not match the studies time period? There must be SST data for that same region for that same period?

Figure 8 and lines 145 show the temperature and tide heights. The interactions between the surface conditions (wind, rainfall etc) and the temperature need to be explored more. What wind conditions prevailed and is this a significant factor? The temperature dropped significantly in the 10 day collection period. What factors are at play here? Is upwelling an event here?

Line 191 has there been any other observed changes in the lagoon? Such as macroalgae cover etc.? Is there any other survey data to shed light on changes that might be occurring in the ecology?

 

 

 

 

Author Response

This paper takes a very basic data set of one location over a 10 year period and highlights how changes can be observed. This is useful as a building block to more sophisticated studies but I do encourage the authors to integrate more factors to the study such as wind and rain long term changes if possible. My comments are minor in this respect.

Thank you for this suggestion. We agree that this study is just a building block for future studies. There were and are no wind or rain monitoring stations at WWC. We are advocating for someone to start such a rigorous monitoring program (see our discussion).

Line 59 is there a picture of the loggers? Can the logger location be shown on the figure 2? The logger location was on the dock piling adajacent to this photo in Fig 2.

We did not take a photo of the logger underwater, regrettably. The type of logger we used can be viewed at the manufactures website.             https://www.onsetcomp.com/products/dataloggers/utbi001?creative=178262173812&keyword=&matchtype=&network=g&device=c&gclid=CjwKCAiAbmsBhAGEiwAoaQNmgRJ0NNBSSmcLEXCVrSNxRRhvaKkC6s5MtKJzIl50L5JT9PJthdDtBoCJmAQAvD_BwE

Line 70 ‘in blue’ refers to which figure?  Line 70 is in the methods, It refers to Figure 8, as noted in the results section.

We deleted (in blue) from methods and it is now in results section 3.5 along with figure 8.

Line 70 Also four loggers are mentioned at various depths, why were not these loggers left for longer?

 It was not feasible to do so within the scope of this study.

Figures 4 & 5 linear regressions of the long term data are not entirely useful. Small changes are masked and outliers have disproportionately influenced the slope. A more sophisticated approach is really required here where by some data is removed and the trend is modelled with prediction as the key mechanism to evaluation.  Showing the variance is always useful here too. The subsequent sections that show the days exceeding a threshold such as degree-heating-weeks is better, especially if the paper is about the biological impact.

Our objective is to only reveal the trend thru time. We added additional figures 9 and 10 which eliminate outliers. Fig 10 shows variance (%CI) among months.

Table 4. why does the SST comparison not match the studies time period? There must be SST data for that same region for that same period?

We added direct comparison to satellite data in TWO NEW FIGURES (9 & 10).

Figure 8 and lines 145 show the temperature and tide heights. The interactions between the surface conditions (wind, rainfall etc) and the temperature need to be explored more. What wind conditions prevailed and is this a significant factor? The temperature dropped significantly in the 10 day collection period. What factors are at play here? Is upwelling an event here?

All good questions but are beyond the scope of this study. The purpose here is to note the overall increase in water temperature inside of the lagoon. The reviewer makes a good point but to do a proper study of weather and other factors, a larger area and additional loggers should be used. We write in the discussion “A consideration for future researchers deploying temperature loggers is to standardize depth of the logger stations to provide better comparability of the data from different locations.”

Line 191 has there been any other observed changes in the lagoon? Such as macroalgae cover etc.? Is there any other survey data to shed light on changes that might be occurring in the ecology?

There have been studies of coral bleaching. We hope this paper alerts future researchers that monitoring needs to be done and studies on fishes thermal tolerances are also needed.