藻源性有机质对高原深水湖泊沉积物矿化作用的激发效应  

Priming effects of algae-derived organic matter on sediment mineralization in a deep-water plateau lake

作　　者：沈悦 杜先 张璐 张一泉 荀凡 柯凡[1] 冯慕华[1] Shen Yue;Du Xian;Zhang Lu;Zhang Yiquan;Xun Fan;Ke Fan;Feng Muhua(State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,P.R.China;University of Chinese Academy of Sciences,Beijing 100049,P.R.China;Geological Environment Monitoring and Protection Station of Shiyan,Shiyan 442099,P.R.China;College of Hydrology and Water Resources,Hohai University,Nanjing 210098,P.R.China)

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]中国科学院大学,北京100049 [3]湖北省十堰地质环境监测保护站,十堰442099 [4]河海大学水文水资源学院,南京210098

出　　处：《湖泊科学》2023年第1期103-117,I0005,I0006,共17页Journal of Lake Sciences

基　　金：国家自然科学基金项目(41877482,41471075);NSFC-云南联合基金项目(U2102216);江苏省高校水处理技术与材料协同创新中心项目联合资助。

摘　　要：湖泊营养水平提升,浮游植物快速增殖,大量藻类碎屑沉降到沉积物表面。藻屑作为新生不稳定有机质,对湖泊沉积物有机质(SOM)产生激发效应,影响湖泊沉积物碳循环过程。本文以深水湖泊抚仙湖南湖心沉积物为研究对象,采用优势种水华束丝藻(Aphanizomenon flos-aquae),进行不同浓度藻屑添加(×1倍组、×5倍组和×10倍组)的培养实验。应用碳同位素在线监测仪,探究藻屑添加对于SOM矿化作用的激发效应并预测可能产生的环境效应。结果表明:(1)添加的藻屑对上覆水和间隙水发光性溶解性有机质(CDOM)组成和性质产生影响,前期CDOM中类蛋白组分含量显著增加,但后期CDOM腐殖化程度升高。同时,藻屑的添加使二氧化碳(CO_(2))释放量增大,蛋白酶活性和转化酶活性增强;(2)3个不同浓度的藻屑添加组均检测到不同程度激发效应,其中×1倍组和×5倍组对SOM矿化过程前期体现为正激发效应,最大值分别达到(12.18±0.65)和(26.60±9.14)μg/(mL ws),后期两个组别都转为负激发效应;×10倍组则在整个实验过程中均表现为负激发效应;(3)藻屑的添加使得间隙水易于富集亚铁离子(Fe^(2+))和硫离子(S^(2-));且沉积物反硝化作用受到抑制,易于富集硝酸根(NO_(3)^(-));同时沉积物碱性磷酸酶活性升高,促进活性磷释放,藻屑的添加增大了抚仙湖沉积物产生黑色物质和水体富营养化的风险。因此系统研究新生有机质输入对抚仙湖SOM的生物地球化学过程的影响将为保护抚仙湖提供理论依据。With the improvement of aquatic trophic level,phytoplankton proliferates rapidly,and a large amount of algae debris finally settled on the surface of sediments.Priming effect would occur on the sediment organic matter(SOM)due to the deposition of algae debris,a fresh labile organic matter,which would affect the cycling process of carbon in sediments.In the current study,the sediments in the southern lake center of Lake Fuxian,the second deepest lake in China,was selected as the research object,and the dominant species Aphanizomenon flos-aquae in Lake Fuxian was chosen to carry out the cultivation experiments with different concentrations of algae debris(×1,×5 and×10 treatments).The carbon isotope on-line monitor was conducted to explore the priming effect of algae debris on SOM mineralization and to predict the possible environmental influence.The results revealed that:(1)the addition of algae debris increased the concentrations of CDOM,and influenced the compositions and properties of chromophoric dissolved organic matter(CDOM)in both overlying water and porewater of sediments.It significantly increased the content of protein-like components in CDOM at the earlier stage,and the humification degree of CDOM at the later stage.The addition of algae debris increased the release of CO_(2) and the activity of proteinase and invertase simultaneously as well;(2)different levels of priming effect were detected in the algae debris addition treatments.The positive priming effect on the SOM mineralization was found in×1 and×5 treatments at the early stage,and then turned into negative excitation effect afterwards,with the highest priming effects of(12.18±0.65)and(26.60±9.14)μg/(mL ws),respectively,while the negative priming effect was shown in×10 treatment during the whole experiment;(3)the addition of algae debris improved the enrichment of Fe^(2+)and S^(2-)in porewater and inhibited the denitrification rate,of sediments,which helps to enrich NO_(3)^(-).The activity of alkaline phosphatase in sediments increased d

关 键 词：藻源性有机质 CDOM 激发效应 环境效应 抚仙湖 

分 类 号：X524[环境科学与工程—环境工程]