[Microbial biomass and its correlations with carbon, nitrogen, and phosphorus in the sediments of Taihu Lake].

To explore the responses and feedbacks of the microbes in the sediments of Taihu Lake to the sediment nutrients, an investigation was made on the microbial biomass carbon (MB(C)), microbial biomass nitrogen (MB(N)), microbial biomass phosphorus (MB(P)), and their correlations with the total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) in the sediments. The microbial biomass in the sediments was 184.66 mg x kg(-1), being higher at the lakeside than in the mid-lake region. The MB(C) was higher in the western coastal region, Zhushan Bay, and Meiliang Bay, with an average of 127.57 mg x kg(-1), MB(N) was higher in Meiliang Bay, Gonghu Bay, mid-lake region close to Meiliang Bay and Gonghu Bay, and eastern costal region, with an average of 19.25 mg x kg(-1), and MB(P) was higher in the eastern region and parts of the mid-lake region, with an average was 19.09 mg x kg(-1). The TOC high value zone (> or = 2.30 g x kg(-1)) was mainly in Zhushan Bay, western coastal region, Meiliang Bay, and Gonghu Bay, with an average of 1.59 g x kg(-1), TN high value zone (> or = 0.30 g x kg(-1)) was mainly in the Gonghu Bay, Meiliang Bay, Zhushan Bay, and western costal region, with an average of 0.21 g x kg(-1), and TP high value zone (> or = 1.20 g x kg(-1)) was mainly in the eastern coastal region and parts of the mid-lake region, with an average of 0.55 g x kg(-1). The TOC/TN ratio in the sediments was 7-19, with an average of 8.97, which showed that the organic substances in the sediments had obvious dual sources, among which, terrestrial organisms were mainly in the west side of the lake. The microbial biomass in the sediments was significantly positively correlated with sediment TOC and TN but had less correlation with sediment TP, and the MB(C)/MB(N) was significantly correlated with sediment TOC/TN, suggesting that the microbes in the sediments of Taihu Lake were mainly affected by the sediment TOC and TN, and the changes of the TOC/TN had significant effects on the microbial community structure.