Seasonal Distribution of Epipelic Diatom Assemblages and Relations to Environmental Variables in a Mesotrophic Pond

Abstract

The seasonal succession of diatom species in the epipelon of shallow, mesotrophic pond OMU Pond I (Turkey) with special attention to diatoms (particularly Navicula) is described. The composition of epipelic algal assemblages changed over time in both higher taxonomic groupings and species representations. September month was characterised by a dominance of Navicula hungarica var. capitata. The occurrence of diatom species also correlated with water temperature. However, although the growth of some species was restricted to a particular month, other species or species complexes had more extended growth periods. Navicula cryptocephala and Amphora ovalis species have been selected to demonstrate variation in temporal distribution within species complexes. Using the epipelic diatoms as indicators of environmental conditions, OMU Pond I was characterised with regard to their water chemistry. Samples were collected, species richness and diversity (Shannon-Wiener, H’) were measured monthly. The results of analysis have supported the results of the counting method. Multivariate analyses indicated that both the regional distribution and seasonal variation of benthic diatoms are mainly driven by nutrient concentration. Diatoms are predominantly affected by geochemical characteristics including temperature and dissolved oxygen levels. © 2016, Scibulcom Ltd. All rights reserved.