\documentclass[10pt]{article} \usepackage{fullpage} \usepackage{setspace} \usepackage{parskip} \usepackage{titlesec} \usepackage[section]{placeins} \usepackage{xcolor} \usepackage{breakcites} \usepackage{lineno} \usepackage{hyphenat} \PassOptionsToPackage{hyphens}{url} \usepackage[colorlinks = true, linkcolor = blue, urlcolor = blue, citecolor = blue, anchorcolor = blue]{hyperref} \usepackage{etoolbox} \makeatletter \patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{% \errmessage{\noexpand\@combinedblfloats could not be patched}% }% \makeatother \usepackage[round]{natbib} \let\cite\citep \renewenvironment{abstract} {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize} {\bigskip} \titlespacing{\section}{0pt}{*3}{*1} \titlespacing{\subsection}{0pt}{*2}{*0.5} \titlespacing{\subsubsection}{0pt}{*1.5}{0pt} \usepackage{authblk} \usepackage{graphicx} \usepackage[space]{grffile} \usepackage{latexsym} \usepackage{textcomp} \usepackage{longtable} \usepackage{tabulary} \usepackage{booktabs,array,multirow} \usepackage{amsfonts,amsmath,amssymb} \providecommand\citet{\cite} \providecommand\citep{\cite} \providecommand\citealt{\cite} % You can conditionalize code for latexml or normal latex using this. \newif\iflatexml\latexmlfalse \providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}% \AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}} \usepackage[utf8]{inputenc} \usepackage[ngerman,english]{babel} \begin{document} \title{Comments on ``An empirical test of the temperature dependence of carrying capacity''} \author[1]{Kristina Riemer}% \author[1]{Hao Ye}% \affil[1]{University of Florida}% \vspace{-1em} \date{\today} \begingroup \let\center\flushleft \let\endcenter\endflushleft \maketitle \endgroup \selectlanguage{english} \begin{abstract} This is a preprint review of~\textbf{An empirical test of the temperature dependence of carrying capacity} by Joey Bernhardt, Jennifer M. Sunday, and Mary I. O'Connor. The preprint was originally posted on bioRxiv on October 28, 2017 (DOI:~\url{https://doi.org/10.1101/210690}).% \end{abstract}% \sloppy ~ ~ In this manuscript, the authors use an experimental approach to determine how temperature affects population carrying capacity. As predicted by metabolic scaling theory, carrying capacity decreases with higher temperatures because individuals use more resources. However, carrying capacity did not scale as a simple function of the activation energy of metabolism, because of a concomitant decrease in body size due to temperature increase, which somewhat reduced resource requirements per individual. \par\null The authors do an excellent job of showing that there is a gap in our collective knowledge about how temperatures impact carrying capacities of populations. This then motivates their chosen experimental design in which temperatures of mesocosms containing a phytoplankton species were manipulated and the resulting photosynthesis and respiration rates were measured. They also calculated expected carrying capacities based on several theoretical equations, which were explained very clearly.~~ \par\null We have two suggestions for how this manuscript could be improved. First, the abstract mentions that the results of this work could have implications for global change scenarios and the final sentence mentions the impacts of the results on various ecological levels. Expanding on these possible implications in the discussion would strengthen the paper and provide potential next steps. For example: \begin{itemize} \tightlist \item what are the potential impacts in ecological communities when species respond differentially or have interdependencies? \item how could changing nutrient uptake impact ecosystem-level processes? \end{itemize} Second, some of the experimental temperatures seemed to surpass the thermal optimum for the study species. It might be useful to present these results in a supplement, including the non-linear activation energy trend, photosynthesis rates, and body sizes for these temperatures. If global temperatures increase above species' thermal optima, these data are beneficial for understanding species responses. \par\null The following are minor concerns about the manuscript: \begin{itemize} \tightlist \item Clarification of the terms ``density'' and ``abundance'' early in the introduction would be helpful. For instance, line 38 in the abstract refers to~\(K\) as ``population abundance at carrying capacity'', while lines 55-56, and line 166 seem to refer to~\(K\)~as density. Strictly speaking, they are not the same, and interchanging their usage will be confusing to some readers. \item The derivation in lines 141-143 seem to assume that~\(E(M) = E_0\), which seems like it could contradict the assumption in lines 131-132 that~\(E(M)\) is linearly related to mass. Can you clarify? \item The description of the hypotheses (lines 188-200) is somewhat dense with technical jargon. Can it be clarified (possibly with simple equations) for the non-specialized reader? This would help to frame the remainder of the paper, too. For example, it's not clear at first glance that hypothesis 2 is about the relationship between temperature and body mass as opposed to temperature and carrying capacity. \item Why is there a difference in light concentrations on lines 218 and 244? \item Small improvements to Fig. 1 including making the tick marks for temperature in \selectlanguage{ngerman}°C match the values that were tested (and include those on lines 214-215 in the methods) and fixing the typo in ``oyxygen'' in the y axis. \item Would be helpful at beginning of results, first sentence, to clarify that the activation energy is estimated from the slope of the line in Figure 1. Similarly, on lines 235-237 of the methods. \item It would be useful to specify why chlorophyll-a was measured in these experiments - is it an additional control measure of productivity? \item The results described on lines 305-307 (population-level chlorophyll decreases with temperature) do not seem to have an associated figure. \end{itemize} Overall, we greatly enjoyed reading the paper and think it makes substantial contributions to the applications of metabolic scaling theory to population ecology. We would have been happy to receive this work as reviewers and hope it sees publication soon in an appropriate journal. \selectlanguage{english} \FloatBarrier \end{document}