Response Of Bacterial Community And Physical And Chemical Factors To Algal Bloom In Xinglin Bay

In this study,physical and chemical factors?temperature?T?,dissolved oxygen?DO?,ammonia nitrogen?NH₄⁺-N?,oxidation-reduction potential?ORP?,total nitrogen?TN?,nitrite nitrogen?NO₂^--N?,total phosphorus?TP?,chlorophyll a?Chl a??were monitored duiring the algal bloom period and non-algal bloom period from August 2016 to November 2016 at the upper reaches of Xinglin Bay Reservoir in Xiamen.The diversity of bacteria communities in water was determined by high-throughput sequencing molecular biology technique.?1?The results showed that there was a significant difference in the concentration of chlorophyll a between bloom and non-bloom periods?p<0.001?.There was no significant correlation between the physical and chemical factors and chlorophyll a.Except for water temperature,oxidation-reduction potential,ammonia nitrogen,total phosphorus and phosphate phosphorus,the other factors in the two periods were significantly?p<0.005?or extremely significantly different?p<0.001?.The comprehensive nutrient index showed that the water area was in a severe eutrophication state by Carlon's nutritional state method,which was 78.32±2.63in the bloom period and 72.24±2.57 in the non-bloom period.?2?the abundance of bacteria during the algal bloom period was lower than that in non the algal bloom period.Bacterial diversity was significantly different in the two periods?p<0.05?.Shannon-Wiener diversity index?H'?of the bacterial communities ranged from 5.50 to 7.60,with an average of 6.03 and 7.10 for the two periods,respectively.There were significant differences in diversity index between the two pools?p<0.05?.The network analysis showed that the species diversity in non-algal bloom period was higher than that in the algal bloom period.The results of high throughput sequencing showed that the dominant flora in the two stages belonged to Cyanobacteria,Proteobacteria and Actinobacteria.Neutral model showed that the microbial community was less affected by environmental factors,which might be related to the long-term severe eutrophication in the water.