太湖沉积物微生物生物量及其与碳、氮、磷的相关性

对太湖沉积物中微生物生物量碳(MBc)、氮(MBN)、磷(MBp),以及沉积物总有机碳(TOC)、总氮(TN)、总磷(TP)进行测定并进行相关性分析,揭示太湖沉积物微生物对太湖沉积物营养盐的响应及反馈特征.结果表明:沉积物微生物生物量(MB)在湖体沿岸地区大于湖心区,平均值为184.66 mg·kg-1,MBc在西部沿岸区以及竺山湾和梅梁湾区域较高,平均值为127.57 mg·kg-1；MBN在梅梁湾、贡湖部分区域以及靠近梅梁湾和贡湖的湖心区域和东部沿岸区较高,平均值为19.25 mg·kg-1；MBp在东部沿岸区及其附近的湖心区最高,平均值为19.09 mg·kg-1；沉积物TOC高值区(≥2.30 g· kg-1)主要集中在竺山湾、西部沿岸区、梅梁湾、贡湖地区,平均值为1.59 g·kg-1；沉积物TN高值区(≥0.30g· kg-1)主要集中在贡湖、梅梁湾、竺山湾部分地区以及西部沿岸区,平均值为0.21 g·kg-1；沉积物TP高值区(≥1.20g·kg-1)主要集中在东部沿岸区以及湖心部分区域,平均值为0.55 g·kg-1；太湖沉积物TOC/TN在7～19,平均值为8.97,表明太湖沉积物中的有机质具有明显的双重来源,其中陆源有机质主要集中在西部沿岸区；太湖沉积物MB与沉积物TOC和TN呈显著正相关,与沉积物TP相关性不显著；沉积物MBc/MBN与沉积物TOC/TN显著相关.太湖沉积物微生物主要受沉积物TOC、TN影响,且沉积物TOC/TN的变化显著影响微生物群落结构.

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(MBC),microbial biomass nitrogen(MBN),microbial biomass phosphorus(MBP),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·kg-1,being higher at the lakeside than in the mid-lake region.The MBC was higher in the western coastal region,Zhushan Bay,and Meiliang Bay,with an average of 127.57 mg·kg-1,MBN 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·kg-1,and MBP was higher in the eastern region and parts of the mid-lake region,with an average was 19.09 mg·kg-1.The TOC high value zone(≥2.30 g·kg-1) was mainly in Zhushan Bay,western coastal region,Meiliang Bay,and Gonghu Bay,with an average of 1.59 g·kg-1,TN high value zone(≥0.30 g·kg-1) was mainly in the Gonghu Bay,Meiliang Bay,Zhushan Bay,and western costal region,with an average of 0.21 g·kg-1,and TP high value zone(≥1.20 g·kg-1) was mainly in the eastern coastal region and parts of the mid-lake region,with an average of 0.55 g·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 MBC/MBN 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.