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Published research suggests that the total phosphorus ( TP) thresholds for the regime shifts between a clear-water state dominated by submersed macrophytes and a turbid-water state dominated by phytoplankton in shallow lakes vary with forms of lake basins and climates. However, such hypotheses remain untested by direct field evidence. We therefore tested the hypotheses with empirical data from subtropical lakes on the Yangtze floodplain and also from other lakes in temperate to tropical zones., TP thresholds were found to vary little at moderate depths, but to decrease notably when depth exceeds a level of probably 3-4 m, and increase sharply when depth is below a level of around 1-2 m., TP thresholds were found to be nearly equal in shallow lakes (1-2 m

Dolman (2014) argued that our recent finding (Wang et al., 2014) of no marked effect of submerged macrophytes on the chlorophyll a (Chl a) to total phosphorus ( TP) relationship in Yangtze subtropical lakes may not necessarily be valid due to the statistical procedure used to analyse the relationship between these two variables., We agree with Dolman (2014) that a likelihood ratio test could provide an alternative statistical approach to analyse the effect of macrophytes on Chl a versus TP. However, we do not consider it would be appropriate to use the test on only a limited sub-data set corresponding to where TP values overlap for the vegetated and non-vegetated states, as suggested by Dolman (2014)., Besides testing slopes of the log10(Chl a)-log10( TP) relationship, we compared log10(Chl a)/log10( TP) values between vegetated and non-vegetated lakes at a range of overlapping TP concentrations (Wang et al., 2014)., The conclusion drawn by Dolman (2014) from a highly cited work on subtropical lakes in Florida was shown to be invalid. Re-analysis of these lakes demonstrated similar results to those found in Yangtze subtropical lakes. We therefore consider that our original conclusions are valid and that submersed macrophytes in subtropical lakes do not necessarily exert the same strong effects on algal turbidity as in temperate lakes. [ABSTRACT FROM AUTHOR]