Exploring temporal trend of morphological variability of a dominant diatom in response to environmental factors in a large subtropical river

摘要

The temporal trend of morphological variability of Aulacoseira granulate (Ehrenberg) Simonsen and its response to environments was studied within the downstream region of a large subtropical river, the Pearl River (China), through time-series sampling during 2009. Both wavelet analysis and redundancy analysis (RDA) were used to demonstrate not only the correlations between morphological parameters but also the correlations between morphology and environments. High coherence between morphological parameters, especially cell size, was confirmed; but the coherence, especially that between cell and filament, could easily be impacted by water turbulence which was associated with discharge, this might reflect the interaction between life cycle and size selectivity. Moreover, phase angles in wavelet figures illustrated that cell diameter was the most sensitive parameter to environmental variations, and changes in cell diameter triggered the size change in both cell and filament; thus through this way cell and filament size variations could be related.