Temporal variation of benthic diatom assemblages in tidal flat of Geunso Bay, Korea

Abstract

Benthic diatoms are ubiquitous in tidal flats and play major roles in maintaining coastal ecosystems. We investigated the temporal variation of benthic diatom composition by MiSeq sequencing of rbcL gene in a total of 80 samples collected from May 2009 to May 2015 at tidal flat in Guenso Bay, Korea. In result of meta-barcoding, Navicula was the most abundant genus, followed by Nitzschia, Amphora, Sellaphora, and Entomoneis. The concentration of chlorophyll a in the study area was high in winter and spring, and the relative frequency of Navicula and Ntizschia increased mainly during this period. On the other hand, the relative frequency of Amphora and Sellaphora was increased in summer with low chlorophyll a concentration. Major species in this study area were Navicula salinarum, Ntizschia bergii, Amphora sp., Halamphora montana. Of the 44 OTUs with a relative frequency of 5% or more, only 18 showed more than 98% similarity to the reference database. Based on the results of CCA analysis, it was confirmed that major factors affecting the change of community structure of benthic diatoms in tidal flat were the grain size and sand ratio. In addition, we observed changes in community structure of benthic diatoms due to artificial changes in sediment particle size. The results from the study will establish a basis of benthic diatom dynamics and give us a more advanced way to monitor benthic diatoms that are essential to mrom May 2009 to May 2015 at tidal flat in Guenso Bay, Korea. In result of meta-barcoding, Navicula was the most abundant genus, followed by Nitzschia, Amphora, Sellaphora, and Entomoneis. The concentration of chlorophyll a in the study area was high in winter and spring, and the relative frequency of Navicula and Ntizschia increased mainly during this period. On the other hand, the relative frequency of Amphora and Sellaphora was increased in summer with low chlorophyll a concentration. Major species in this study area were Navicula salinarum, Ntizschia bergii, Amphora sp., Halamphora montana. Of the 44 OTUs with a relative frequency of 5% or more, only 18 showed more than 98% similarity to the reference database. Based on the results of CCA analysis, it was confirmed that major factors affecting the change of community structure of benthic diatoms in tidal flat were the grain size and sand ratio. In addition, we observed changes in community structure of benthic diatoms due to artificial changes in sediment particle size. The results from the study will establish a basis of benthic diatom dynamics and give us a more advanced way to monitor benthic diatoms that are essential to m