环境科学  2024, Vol. 45 Issue (11): 6574-6582   PDF    
寒旱区高盐湖泊溶解性有机质的光学特征及来源解析
王世欢1,2, 史小红1,2, 赵胜男1,2, 陶玉龙1,2,3, 孙标1,2, 冯伟莹4, 张生1,2     
1. 内蒙古农业大学水利与土木建筑工程学院, 呼和浩特 010018;
2. 内蒙古乌梁素海湿地生态系统国家定位观测研究站, 巴彦淖尔 015000;
3. 呼伦贝尔市北方寒冷干旱地区内陆湖泊研究院, 呼伦贝尔 021000;
4. 北京航空航天大学空间与环境学院, 北京 100191
摘要: 为了解生态脆弱的农牧交错地区典型湖泊岱海水体的溶解性有机质(DOM)的成分特征及其来源信息, 使用三维荧光光谱(3DEEM)、平行因子分析模型(PARAFAC)和荧光吸收峰(B、T、A、M、C、D、N)对水体DOM荧光特征进行研究, 探究岱海水体DOM荧光特征与环境因子的关系. 结果表明, 岱海水体整体呈弱碱性, 营养盐浓度较高, 有机污染严重. 岱海水体DOM具有陆源与内源的双重特性, 生物源组分占比较高. PARAFAC解析出3种组分:类色氨酸C1组分、微生物来源腐殖质C2组分和类酪氨酸C3组分. 其中类色氨酸C1组分和微生物来源腐殖质C2组分占DOM总荧光强度的80%左右;荧光吸收峰分析结果显示, 类蛋白荧光吸收峰(B、T、N)总占比为49.67%, 陆源输入主要来源于密集的农业活动和流域生态环境的快速恶化. DOM的组成、转化过程主要与水体营养状态和高盐环境下的微生物过程密切相关, NH4+-N、DOP、TP、DO、高锰酸盐指数等环境因子在此过程中具有显著影响(P < 0.05). 通过揭示岱海水环境现状与DOM环境特征, 可以岱海为例的寒旱区内陆湖泊的环境治理提供基础数据与思路.
关键词: 内陆高盐湖泊      溶解性有机质(DOM)      三维荧光光谱(3DEEM)      平行因子分析(PARAFAC)      荧光吸收峰     
Optical Characteristics and Source Analysis of Dissolved Organic Matter in Hypersaline Lakes in Cold and Arid Regions
WANG Shi-huan1,2 , SHI Xiao-hong1,2 , ZHAO Sheng-nan1,2 , TAO Yu-long1,2,3 , SUN Biao1,2 , FENG Wei-ying4 , ZHANG Sheng1,2     
1. College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China;
2. National Positioning Observatory for Ecosystems in the Ulangsuhai Wetland, Bayannur 015000, China;
3. Inland Lakes Research Institute for Cold and Arid Northern Areas in Hulunbuir, Hulunbuir 021000, China;
4. School of Space and Environment, Beihang University, Beijing 100191, China
Abstract: The composition and source information of the aquatic dissolved organic matter (DOM) in the Daihai Lake, a typical saline lake at the ecologically fragile agro-pastoral area, were explored with three-dimensional excitation and emission matrix fluorescence (3DEEM), parallel factor analysis (PARAFAC), and fluorescence peaks (B, T, A, M, C, D, and N). Further, the relationship between aquatic DOM fluorescence characteristics and environmental factors were analyzed using correlation analysis in the Daihai Lake. The results showed that the water of Daihai was weakly alkaline, with high nutrient salt concentration and serious organic pollution. Two protein-like substances (C1 and C3) and one humic-like substance (C2) were identified using PARAFAC. The sum of C1 + C2 accounted for 80% of DOM. The results of fluorescence peaks showed that the total percentage of protein-like fluorescence absorption peaks (B, T, and N) was 49.67%. Aquatic DOM of Daihai demonstrated both terrigenous and endogenous characteristics. Terrestrial inputs were mainly from intensive agricultural activities and rapid ecological degradation of the watershed leading to large amounts of organic matter entering the lake. The environmental behavior of DOM was highly correlated with the metabolic activity of organisms and nutrient status of lakes. NH4+-N, DOP, TP, DO, and permanganate index characterized the effect of the lake trophic state on DOM composition. DO, SAL, and Chla were mainly related to microbial metabolic processes (P < 0.05). This study provides basic data and insights for the improvement of inland lake environments in saline lakes.
Key words: highly saline inland lakes      dissolved organic matter (DOM)      three-dimensional excitation and emission matrix fluorescence (3DEEM)      parallel factor analysis (PARAFAC)      fluorescence peaks     

在气候变化和人类活动的影响下, 湖面快速萎缩、水资源短缺、水生态退化和盐碱化是寒旱区湖泊普遍面临的问题[1 ~ 3].有研究表明, 内蒙古各典型湖泊呈现不同程度的富营养化状态[4], 其中岱海、达里诺尔湖[5]、通古淖尔和巴丹湖(西)[2]盐碱化严重, 其对于寒冷-干旱-强季风下的动态多变气候较其他淡水湖泊更为敏感.湖泊盐碱化过程中将改变水体营养盐转化过程[6, 7]、生物群落结构[8]以及其他生物地球化学过程, 并导致更高的有机质累积[9].因此, 了解高盐湖泊的环境特征和溶解性有机质(DOM)特性, 对于寒旱区高盐湖泊生态系统的物质循环和环境修复具有重要意义.

溶解性有机质(DOM)是由脂质、蛋白质、腐植酸和其他活性有机化合物组成的化学复杂的非均质有机混合物, 其广泛存在于天然水体中, 是湖泊生态系统的重要组成部分[10, 11].DOM的数量与质量是由其来源和水环境的生物地球化学过程共同影响的结果.天然水体中的DOM来源可以按内源和外源区分[12], 内源与水体生物活动联系密切, 即水体中水生植物、藻类、细菌等生物的分泌物和新陈代谢产物生成, 表现为以类蛋白质为主[12];外源则是大气、陆地系统中的有机质通过降雨、地表径流和下渗等方式进入水体, 主要表现为类腐殖质物质[13, 14]. DOM的结构与组成决定着其在生态系统中的作用, 一些具有高化学活性的组分可以影响水环境中的一系列生物、物理和化学过程[15, 16], 例如络合、生物降解和光降解等[17 ~ 19], 同时也通过相互作用影响着入湖污染物的分布、转化、生物利用度和毒性等环境行为过程(如重金属、微塑料等)[20 ~ 22].

目前国内外表征DOM的方法众多, 如傅里叶变换离子共振质谱(FT-ICR-MS)、傅里叶红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)、三维荧光光谱(EEMS)和高效液相色谱法等[23, 24].三维荧光光谱结合平行因子分析(PARAFAC)获取批量数据的共性荧光峰而被广泛应用, 荧光区域积分法(FRI)和荧光峰(B、T、A、M、C、D、N)可以定量揭示DOM各组分的特征[25], 荧光参数(FI、βα、BIX和HIX)可在一定程度上为DOM的腐殖化程度、微生物活性、来源及其环境行为提供相关信息[26 ~ 28].

岱海是我国北方干旱与半干旱地区典型的内陆封闭咸水湖泊, 在维持区域生态系统服务方面发挥着重要的作用.近年来在人类活动和气候变化的影响下, 岱海湖泊生态系统退化加速, 入湖水量锐减使得岱海水位持续下降, 湖面萎缩[29]、湖水盐渍化和有机质累积等问题严峻, 流域生态系统已处于崩溃边缘[30].2005年以来岱海水质恶化严重, 其TP、TN和高锰酸盐指数是其主要污染指标[31], 在过去的15年间, 岱海ρ(TP)、ρ(TN)和高锰酸盐指数分别由0.072、1.506和16.73 mg·L-1增长至0.126、3.695和19.83 mg·L-1, 增长幅度分别达74.53%、145.38%和18.52%.大量学者对岱海水质、湖泊富营养化及微生物等方面进行研究[1, 32, 33], 但尚缺乏对岱海为代表的高盐和高矿化度寒区湖泊水体DOM特征的了解.本文通过三维荧光光谱结合平行因子分析模型对岱海DOM进行研究, 对岱海溶解性有机质组成及其主要来源进行探究, 并剖析了寒区高盐环境下湖泊营养状态与生态特征对水体DOM的影响, 以期为寒旱区内陆高盐湖泊的环境治理提供基础数据与思路.

1 材料与方法 1.1 研究区域概况

岱海位于内蒙古自治区乌兰察布市凉城县境内, 是国家级重要湿地.岱海流域位于农牧交错带, 流域面积约2 312.75 km2, 生态环境脆弱, 主要受中温带半干旱大陆性季风气候的影响.岱海四周环山, 属于典型的内陆咸水湖泊, 水体盐度和总溶解性固体ρ(TDS)均值分别为15.42‰和16 442.21 mg·L-1.湖泊水域面积约为47.86 km2(2021年), 南北宽约为8 km, 东西长为13 km, 平均水深为4.64 m, 降水少而蒸发强度大, 多年平均降水量为406.32 mm, 而多年平均蒸发量为2 043.36 mm, 二者相差5倍左右.湖泊的主要补给源为湖面降水、地表径流和地下水补给.

1.2 样品采集与处理

依据水深、湖形及湖底地形等要素在岱海均匀布设取样点(图 1), 于2021年4月下旬进行野外调研和样品采集, 使用便携式多参数水质分析仪(YSI)现场测定pH值、溶解氧(DO)、电导率(Cond)、总溶解性固体(TDS)、盐度(SAL)和水温(T)等指标, 使用塞氏盘测定透明度(SD).采集样品保存于无菌聚乙烯取样瓶中, 于4℃的保温箱中避光保存, 带回实验室并进行相关指标测定.原水样测定叶绿素a(Chla)、总氮(TN)、总磷(TP)、重铬酸盐指数、高锰酸盐指数和五日生化需氧量(BOD5)等指标.用于荧光光谱测定的水样使用0.7 μm的玻璃纤维滤膜(Whatman, 450 ℃灼烧4 h)抽滤, 并测定溶解性总磷(DTP)、溶解性无机磷(DIP)、氨氮(NH4+-N)和溶解性有机碳(DOC)等指标, 具体步骤按照《水和废水监测分析方法》进行.

图 1 岱海流域及取样点布设示意 Fig. 1 Location of Daihai Lake and sampling sites

1.3 分析方法

使用荧光分光光度计(Lab Solutions RF-6000)进行三维荧光光谱测定, 以当日Mill-Q水为空白样对三维荧光光谱进行校正, 以减少仪器和拉曼散射对荧光光谱的影响.原水样用Mill-Q超纯水进行稀释, 使其在波长254 nm处的紫外吸光度小于0.1, 以降低荧光淬灭作用.扫描波长范围为激发波长(Ex)200~450 nm, 间隔和激发光带宽度分别为2.0 nm和5.0 nm, 发射波长(Em)为250~600 nm, 间隔和发射光带宽度为1.0 nm和5.0 nm.

平行因子分析法(PARARAC).利用MATLAB 2016a软件DOMFluor工具箱运行PARARAC模型对三维荧光光谱数据进行分析, 首先, 将瑞利散射明显区域(发射波长-激发波长 < 20 nm)置0来消除一级和二级瑞利散射对光谱的影响, 通过杠杆测试去除异常样本值, 然后依次构建2~7个组分的数学模型, 使用裂半分析(split-half analysis)和Tucker's全等系数来验证模型的可靠性, 并计算相关荧光参数[11, 13].具体相关参数如表 1所示.

表 1 三维荧光光谱的相关参数描述 Table 1 Parameters of 3D-EEM

荧光吸收峰.不同的荧光峰(B、T、A、M、C、D和N)代表着不同的有机质组分[25], B峰(Ex/Em = 275 nm/305 nm)为类酪氨酸, T峰(Ex/Em = 275 nm/340 nm)为类色氨酸, A峰(Ex/Em = 260 nm/400~460 nm)为紫外区类腐殖质, C峰(Ex/Em = 320~360 nm/420~460 nm)为可见光区类腐殖质, M峰(Ex/Em = 290~310 nm/370~410 nm)为微生物来源的腐殖质, D峰(Ex/Em = 390 nm/509 nm)为陆源富里酸, N峰(Ex/Em = 280 nm/370 nm)为生物源DOM.

1.4 数据分析

使用MATLAB 2016a进行三维荧光光谱平行因子分析和荧光吸收峰计算;Pearson相关分析和RDA分析使用R语言进行;各数据的标准化、均值和单因素方差分析(One-Way ANOVA)使用IBM SPSS Statistics 22软件进行.

2 结果与分析 2.1 岱海水环境现状

岱海水体pH均值为9.03(范围为8.95~9.06), 呈弱碱性, 水温均值为10.94 ℃(范围为9.3~14.5 ℃), Cond均值为18.50 μS·cm-1(范围为17.75~20.16 μS·cm-1), 见图 2.根据《地表水环境质量标准》(GB 3838-2002), 检测结果表明, TN浓度、有机污染物指标高锰酸盐指数和重铬酸钾指数都已超过Ⅴ类水最高限值, 为劣Ⅴ类, 其中重铬酸钾指数为Ⅴ类水最高限值的4.8倍, ρ(TP)均值为0.13 mg·L-1, 为Ⅴ类.根据单因素方差分析(ANOVA)结果显示, 表层水体的水温、DO和Cond显著高于底层水体(P < 0.05), 表层水体Chla浓度显著低于底层水体(P < 0.01).

图 2 岱海主要水质指标 Fig. 2 Major physical and chemical index

2.2 水体DOM的表征分析

利用PARAFAC分析模型对岱海水体DOM的三维荧光光谱矩阵数据进行分析, 并解析出3个荧光组分(表 2图 3).C1和C3分别表示类色氨酸和类酪氨酸DOM, 代表来自微生物形成代谢的蛋白质化合物, 如氨基酸、肽类物质和游离态或结合态的蛋白质[36, 37];C2组分为微生物代谢相关的腐殖质, 主要为陆源输入腐殖质组分受微生物转化的产物, 为新产生且相对不稳定的DOM组分, 在淡水生态系统中广泛存在[38].

表 2 3种组分的荧光光谱特征 Table 2 Characteristics of fluorescence spectrum

图 3 基于PARAFAC模型的3种荧光组分及波长 Fig. 3 Fluorescence component and wavelength based on PARAFAC model

岱海水体3种DOM荧光组分空间分布差异较大(图 4).其中各组分占总荧光强度的比例, 在表层为:C2(47.72%) > C1(33.36%) > C3(18.92%), 在中层为:C1(40.98%) > C2(39.12%) > C3(19.90%), 在底层为:C1(47.68%) > C2(34.29%) > C3(18.03%).由此可见, 岱海水体DOM主要由C1和C2组成, 占总荧光强度的80%左右, 并且由表层水体至底层水体C1组分荧光强度占比增加, C2组分则为与之相反的变化特征.水体中较高含量的类色氨酸和微生物来源腐殖质与其他盐湖特征相似, 各组分荧光强度明显的垂向变化特征则可能是受沉积物中微生物代谢活动的影响[45].

1.表层, 2.中层, 3.底层 图 4 岱海水体DOM组分荧光相对丰度 Fig. 4 Relative abundance of fluorescence of DOM fractions

为进一步探索岱海水体DOM的组成信息, 选取EEM固定荧光吸收峰(B、T、A、M、C、D和N)进行研究, 其占比关系如图 5所示.岱海水体中M峰(15.95%~35.33%)占比显著高于其他荧光峰(P < 0.01), 其次是T峰(17.29%~22.22%)占比相对较高, C峰(13.23%~19.81%)和N峰(12.42%~17.20%)占比相近, 这一结果与EEM-PARAFAC的分析结果基本一致.整体上, 岱海水体DOM类蛋白组分(B、T和N)总占比为49.67%, 说明水体中生物过程较为显著.

1.表层, 2.中层, 3.底层 图 5 岱海水体荧光吸收峰占比情况 Fig. 5 Percentage of fluorescence absorption peaks

2.3 水体DOM来源解析

岱海表层、中层、底层水体FI均值分别为1.54、1.59和1.57(表 3), 表明岱海水体DOM既有外源输入, 又有内源释放, 即河流补给所携带的陆源有机质与水体微生物代谢产生的有机质, 与上述PARAFAC分析和荧光吸收峰的分析结果一致.水体HIX值范围为0.86~1.81, 表明水体DOM腐质化程度较弱;BIX值和β:α范围分别为1~2.07和0.97~1.93, 表明岱海水体DOM中腐殖化程度较低, 生物源有机组分较多, 这与东非的索纳奇等盐湖和高盐河口区域的特征类似[27, 46].

表 3 岱海水体DOM荧光参数 Table 3 Parameters of DOM fluorescence

2.4 环境因子与DOM荧光组分及参数的相关性

为进一步了解环境因子与岱海水体DOM的关系, 对水环境因子(T、DO、NH4+-N、TP、Chla、高锰酸盐指数、DOP和Cond)与水体DOM组分及荧光参数进行Pearson相关分析(图 6).水体Chla可在一定程度上揭示内源有机质生产潜力, 岱海水体中Chla与C1组分和C2组分呈显著正相关(P < 0.05), 表明水体DOM降解转化过程中生物作用显著, C2组分可能源于细菌与藻类细胞释放的胞外腐殖质. FI与C1组分、Chla呈显著相关(P < 0.05), 说明岱海水体DOM组分与来源具有一致性变化.

1. T, 2. DO, 3. NH4+-N, 4. TP, 5. Chla, 6. 高锰酸盐指数, 7. DOP, 8. Cond, 9. C1, 10. C3, 11. C2, 12. FI, 13. βα, 14. BIX, 15. HIX 图 6 岱海水体环境因子与DOM特征的关系 Fig. 6 Relationship between environmental factors and DOM characteristics of Daihai Lake

3 讨论 3.1 岱海水体不同DOM成分的来源解析

不同来源有机质有着独特的荧光特征, 岱海水体DOM的荧光特征和相关参数分析结果显示(图3~5表 3), 岱海水体有机质具有内源和陆源的双重特征, 其中C1和C2荧光强度约为52.28%.岱海是典型的内陆封闭湖泊, 流域范围内大量的陆源有机质在岱海汇集并沉积[47], 其中部分陆源有机质在微生物作用下转化为内源性有机物[46], 并在沉积物受到扰动时向上覆水体释放.此外, 土地利用变化[48]与水体浮游植物群落结构[49]的改变也是影响岱海水体DOM组分特征重要的因素.

近20 a来, 岱海流域耕地面积增加了15.01%[50], 水域面积由91.47 km2(2004年)减少到48.3 km2(2020年)[51], 密集的农业活动和生态环境的快速恶化导致大量污染物与有机质在雨水冲刷和渗透作用下进入湖体, 造成了水体中陆源腐殖质组分(C2)和营养盐的增加.湖泊干化、盐化以及水体营养盐浓度的增加导致岱海优势藻属由硅藻(2001年)[52]和绿藻(2014年)[53]转变为蓝藻(2021年)[4], 而蓝藻对类色氨酸组分(C1)的增加有正向影响[48], 这也与Zhang等[48]对于浮游植物是介导土地利用变化对水体DOM特征的观点相吻合.

3.2 环境因子与湖泊DOM的响应分析

岱海水体DOM荧光组分特征受多种环境因子的共同影响(图 7), 其中NH4+-N、DOP、TP、DO和高锰酸盐指数与岱海水体DOM组分显著相关.湖泊水体的营养状态及氮磷的养分循环与DOM组成关系密切.岱海在1989年达到中营养状态[54], 现为中度富营养状态.富营养状态促使水体藻类的大量生长与繁殖[55], 增加自生源DOM释放与积累[56], 同时又驱动着细菌对DOM的利用.与其他富营养化湖泊不同的是, 岱海DOM的生物源组分较多、腐质化程度低且含有更少的含硫化合物[24, 57], 这表明岱海较南方湖泊受人类活动影响较小[16, 24], 其生物源组分较多、腐质化程度低与多数盐湖特征类似[27].此外, 高盐、高矿化度的环境特征使得岱海藻类和水生植物生存期缩短、丰度降低, Chla浓度要显著低于南方的富营养状态湖泊[24], 这也是在本研究中Chla浓度未与C3组分呈显著相关的重要原因.

图 7 岱海DOM组分与水体环境因子的RDA排序 Fig. 7 RDA ranking of DOM components with environmental factors in Daihai Lake

DO是影响有机质降解转化的重要环境因子. 一方面, 有机质的降解过程会大量消耗水DO;另一方面, DO会影响水体微生物的群落结构与代谢活动. 有研究表明, 低DO、高营养盐的特征使得岱海沉积物细菌群落比上覆水体细菌群体具有更高的丰富度和均匀度[58], 这进一步促使岱海底层水体DOM受到更强烈的生物作用(图 4). Gao等[33]研究也表明岱海DOM组成与结构受厚壁菌门(Firmicutes)、放线菌门(Actinomarinales)、α-变形菌门(α-Proteobacteria)和酸微菌纲(Acidimicrobiia)等盐湖中典型类群微生物的影响.

3.3 寒旱区内陆湖泊盐碱化的环境影响

湖泊咸化、萎缩是干旱与半干旱地区内陆闭塞湖必然趋势, 但近代以来人类活动加速了这一过程.受气候变化和水资源过度开发利用等原因, 30 a间岱海年均入湖流量补给由7 800万m3[59]减少到312.59万m3(2019年), 水域面积减少了一半以上(1989年水域面积115.36 km2[29], 盐度增长了将近4倍[59], 是相同气候区乌梁素海和呼伦湖的10倍, 是达里诺尔湖的2倍.高盐环境下岱海生物多样性减少, 湖体有机、无机污染物累积严重、水环境持续恶化.随着湖泊盐度的增加, 水体DOC浓度逐渐增高, 整体上高盐湖泊的DOC要显著高于淡水湖泊(表 4).

表 4 不同湖泊盐度、DOC浓度及面积对比1) Table 4 Comparison of salinity and DOC concentration in different lakes

湖泊盐渍化会严重影响有机质的生物过程和光化学过程. 盐度的增加会改变微生物群落结构与代谢作用进而影响水体DOM的组成, 高盐湖泊微生物在抵御高盐胁迫的过程中需开发更广泛的可利用碳源[8]并逐渐进化出降解顽固有机质(木质素和纤维素等)的能力[60], 多数的盐湖DOM受显著微生物活动的影响. 水体中耐光降解和生物降解的DOM组分会在湖泊内累积(脂肪族化合物、木质素等), 易受微生物降解和光降解的有机质(脂类、碳水化合物和不饱和碳氢化合物)则被消耗[61].此外, 湖面的大幅萎缩、水体盐碱化和富营养化、生物多样性锐减等特征表明岱海的生命已岌岌可危, 采取必要的生态补水、控制陆源DOM的输入以及疏浚等生态干预工程, 改善水体盐度和矿化度, 可在一定程度上减轻岱海的环境压力.

4 结论

岱海水体呈弱碱性, TN、TP、高锰酸盐指数和化学需氧量是其主要污染指标.岱海水体DOM具有内源与外源的双重特性, 腐质化程度较低, 类色氨酸C1和微生物来源腐殖质C2占总DOM总荧光强度的80%左右.陆源输入主要是来自于密集的农业活动和流域生态环境的快速恶化导致大量的有机质进入湖体, 水体DOM的转化过程与水体营养状态及高盐环境下的微生物过程密切相关.

参考文献
[1] Yang W H, Ma J, Zhen Y, et al. Community characteristics and functional gene response analysis of phosphorus-metabolizing bacteria in plateau saline lake sediments[J]. Frontiers in Environmental Science, 2022, 10. DOI:10.3389/fenvs.2022.994104
[2] 王欣远, 潘保柱, 王立新, 等. 内蒙古典型湖泊水环境特征及水质评价[J]. 环境科学, 2023, 44(12): 6744-6753.
Wang X Y, Pan B Z, Wang L X, et al. Water environment characteristics and water quality assessment of typical Lakes in Inner Mongolia[J]. Environmental Science, 2023, 44(12): 6744-6753.
[3] 吴用, 史小红, 赵胜男, 等. 内蒙古高原3大典型湖泊水化学特征及其控制因素分析[J]. 生态环境学报, 2015, 24(7): 1202-1208.
Wu Y, Shi X H, Zhao S N, et al. Major ion chemistry and influencing factors of three typical lakes in Inner Mongolia Plateau[J]. Ecology and Environmental Sciences, 2015, 24(7): 1202-1208.
[4] 王世欢, 张生, 武蓉, 等. 寒旱区湖泊浮游植物特征及其对营养状态的指示作用[J]. 中国环境科学, 2023, 43(1): 311-320.
Wang S H, Zhang S, Wu R, et al. Characteristics of phytoplankton in cold and arid areas and their indicator of trophic status[J]. China Environmental Science, 2023, 43(1): 311-320.
[5] 杨富亿, 文波龙, 李晓宇, 等. 达里诺尔湿地水环境和鱼类多样性调查Ⅱ. 达里湖水体的碱度、pH和硬度[J]. 湿地科学, 2020, 18(6): 646-652.
Yang F Y, Wen B L, Li X Y, et al. Investigation of water environment and fish diversity in Dalinor Wetlands Ⅱ. Alkalinity, pH and hardness of the water of Dali Lake[J]. Wetland Science, 2020, 18(6): 646-652.
[6] Wu R, Liu Y, Zhang S, et al. Characterization of nitrogen and phosphorus at the ice-water-sediment interface and the effect of their migration on overlying water quality in Daihai Lake (China) during the freezing period[J]. Science of the Total Environment, 2023, 893. DOI:10.1016/j.scitotenv.2023.164863
[7] Jiang X Y, Liu C Q, Hu Y, et al. Climate-induced salinization may lead to increased lake nitrogen retention[J]. Water Research, 2023, 228. DOI:10.1016/j.watres.2022.119354
[8] Oren A. Thermodynamic limits to microbial life at high salt concentrations[J]. Environmental Microbiology, 2011, 13(8): 1908-1923. DOI:10.1111/j.1462-2920.2010.02365.x
[9] Hornick K M, Buschmann A H. Insights into the diversity and metabolic function of bacterial communities in sediments from Chilean salmon aquaculture sites[J]. Annals of Microbiology, 2018, 68(2): 63-77. DOI:10.1007/s13213-017-1317-8
[10] Zhi E Q, Yu H B, Duan L, et al. Characterization of the composition of water DOM in a surface flow constructed wetland using fluorescence spectroscopy coupled with derivative and PARAFAC[J]. Environmental Earth Sciences, 2015, 73(9): 5153-5161. DOI:10.1007/s12665-015-4148-6
[11] Liu D, Du Y X, Yu S J, et al. Human activities determine quantity and composition of dissolved organic matter in lakes along the Yangtze River[J]. Water Research, 2020, 168. DOI:10.1016/j.watres.2019.115132
[12] McIntyre A M, Guéguen C. Binding interactions of algal-derived dissolved organic matter with metal ions[J]. Chemosphere, 2013, 90(2): 620-626. DOI:10.1016/j.chemosphere.2012.08.057
[13] Duan P F, Wei M J, Yao L G, et al. Relationship between non-point source pollution and fluorescence fingerprint of riverine dissolved organic matter is season dependent[J]. Science of the Total Environment, 2022, 823. DOI:10.1016/j.scitotenv.2022.153617
[14] Butman D, Raymond P A. Significant efflux of carbon dioxide from streams and rivers in the United States[J]. Nature Geoscience, 2011, 4(12): 839-842. DOI:10.1038/ngeo1294
[15] Kellerman A M, Dittmar T, Kothawala D N, et al. Chemodiversity of dissolved organic matter in lakes driven by climate and hydrology[J]. Nature Communications, 2014, 5. DOI:10.1038/ncomms4804
[16] Shang Y X, Wen Z D, Song K S, et al. Natural versus anthropogenic controls on the dissolved organic matter chemistry in lakes across China: insights from optical and molecular level analyses[J]. Water Research, 2022, 221. DOI:10.1016/j.watres.2022.118779
[17] Hansen A M, Kraus T E C, Pellerin B A, et al. Optical properties of dissolved organic matter (DOM): effects of biological and photolytic degradation[J]. Limnology and Oceanography, 2016, 61(3): 1015-1032. DOI:10.1002/lno.10270
[18] 薛飞扬, 秦华伟, 李凤超, 等. 黄河口近岸海域有色溶解有机质的时空分布及光降解特性[J]. 环境化学, 2023, 42(3): 904-917.
Xue F Y, Qin H W, Li F C, et al. Spatial-temporal distribution and photodegradation of chromophoric dissolved organic matter in the coastal waters of the Yellow River Estuary[J]. Environmental Chemistry, 2023, 42(3): 904-917.
[19] Xia X H, Dai Z N, Rabearisoa A H, et al. Comparing humic substance and protein compound effects on the bioaccumulation of perfluoroalkyl substances by Daphnia magna in water[J]. Chemosphere, 2015, 119: 978-986. DOI:10.1016/j.chemosphere.2014.09.034
[20] 刘新, 吴定桂, 江和龙, 等. 草源型可溶性有机物降解过程中活性氧物种产生过程[J]. 湖泊科学, 2020, 32(2): 440-449.
Liu X, Wu D G, Jiang H L, et al. The production process of reactive oxygen radicals in the degradation process of grass-source dissolved organic matter[J]. Journal of Lake Sciences, 2020, 32(2): 440-449.
[21] 肖艳春, 于会彬, 宋永会. 河流底泥DOM、营养盐与重金属空间分异特征及响应关系[J]. 环境科学, 2022, 43(5): 2489-2499.
Xiao Y C, Yu H B, Song Y H. Spatial differentiation characteristics and response relationship of DOM, nutrients, and heavy metals in river sediments[J]. Environmental Science, 2022, 43(5): 2489-2499.
[22] 何泽琴, 李亚飞, 李俊, 等. 典型微塑料对水库缓流区消落带土壤Cu形态的影响及其与DOM的关联[J]. 环境科学学报, 2023, 43(9): 346-356.
He Z Q, Li Y F, Li J, et al. Effect of typical microplastics on soil copper speciation and its association with DOM in water-level-fluctuation zone of slow-flowing area of the reservoir[J]. Acta Scientiae Circumstantiae, 2023, 43(9): 346-356.
[23] Williams C J, Frost P C, Morales-Williams A M, et al. Human activities cause distinct dissolved organic matter composition across freshwater ecosystems[J]. Global Change Biology, 2016, 22(2): 613-626. DOI:10.1111/gcb.13094
[24] Liu S S, Hou J W, Suo C Y, et al. Molecular-level composition of dissolved organic matter in distinct trophic states in Chinese lakes: implications for eutrophic lake management and the global carbon cycle[J]. Water Research, 2022, 217. DOI:10.1016/j.watres.2022.118438
[25] Carstea E M, Bridgeman J, Baker A, et al. Fluorescence spectroscopy for wastewater monitoring: a review[J]. Water Research, 2016, 95: 205-219. DOI:10.1016/j.watres.2016.03.021
[26] Lavonen E E, Kothawala D N, Tranvik L J, et al. Tracking changes in the optical properties and molecular composition of dissolved organic matter during drinking water production[J]. Water Research, 2015, 85: 286-294. DOI:10.1016/j.watres.2015.08.024
[27] Huguet A, Vacher L, Relexans S, et al. Properties of fluorescent dissolved organic matter in the Gironde Estuary[J]. Organic Geochemistry, 2009, 40(6): 706-719. DOI:10.1016/j.orggeochem.2009.03.002
[28] Ni M F, Li S Y. Biodegradability of riverine dissolved organic carbon in a Dry-Hot Valley region: initial trophic controls and variations in chemical composition[J]. Journal of Hydrology, 2019, 574: 430-435. DOI:10.1016/j.jhydrol.2019.04.069
[29] 马倩, 王冉, 谭荣杰, 等. 近40a岱海水域面积与水量变化遥感监测[J]. 人民黄河, 2022, 44(S1): 57-59.
[30] 郭鹏程, 杨司嘉. 岱海水质变化规律及成因分析[J]. 华北水利水电大学学报(自然科学版), 2021, 42(1): 40-46.
Guo P C, Yang S J. Analysis on the characteristics and reasons of Daihai Lake quality change[J]. Journal of North China University of Water Resources and Electric Power (Natural Science Edition), 2021, 42(1): 40-46.
[31] 周云凯, 姜加虎, 黄群, 等. 内蒙古岱海水体营养状况分析[J]. 干旱区地理, 2006, 29(1): 42-46.
Zhou Y K, Jiang J H, Huang Q, et al. Analysis on the trophic status of the Daihai lake in Inner Mongolia[J]. Arid Land Geography, 2006, 29(1): 42-46. DOI:10.3321/j.issn:1000-6060.2006.01.007
[32] 白妙馨, 杨芳, 冯伟莹, 等. 典型半干旱区内陆湖泊富营养化特征分析与评价——以岱海为例[A]. 见: 《环境工程》2019年全国学术年会论文集(下册)[C]. 北京: 《环境工程》编辑部, 2019. 186-196.
[33] Gao J Y, Feng W Y, Yang F, et al. Effects of water quality and bacterial community composition on dissolved organic matter structure in Daihai lake and the mechanisms[J]. Environmental Research, 2022, 214. DOI:10.1016/j.envres.2022.114109
[34] Zsolnay A, Baigar E, Jimenez M, et al. Differentiating with fluorescence spectroscopy the sources of dissolved organic matter in soils subjected to drying[J]. Chemosphere, 1999, 38(1): 45-50. DOI:10.1016/S0045-6535(98)00166-0
[35] 宁成武, 包妍, 黄涛, 等. 夏季巢湖入湖河流溶解性有机质来源及其空间变化[J]. 环境科学, 2021, 42(8): 3743-3752.
Ning C W, Bao Y, Huang T, et al. Sources and spatial variation of dissolved organic matter in summer water of inflow rivers along Chaohu Lake watershed[J]. Environmental Science, 2021, 42(8): 3743-3752.
[36] Eder A, Weigelhofer G, Pucher M, et al. Pathways and composition of dissolved organic carbon in a small agricultural catchment during base flow conditions[J]. Ecohydrology & Hydrobiology, 202, 22(1): 96-112.
[37] Stedmon C A, Thomas D N, Papadimitriou S, et al. Using fluorescence to characterize dissolved organic matter in Antarctic sea ice brines[J]. Journal of Geophysical Research: Biogeosciences, 2011, 116(G3). DOI:10.1029/2011JG001716
[38] Fouché J, Christiansen C T, Lafrenière M J, et al. Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter[J]. Nature Communications, 2020, 11(1). DOI:10.1038/s41467-020-18331-w
[39] Yamashita Y, Scinto L J, Maie N, et al. Dissolved organic matter characteristics across a subtropical wetland's landscape: Application of optical properties in the assessment of environmental dynamics[J]. Ecosystems, 2010, 13(7): 1006-1019. DOI:10.1007/s10021-010-9370-1
[40] Galletti Y, Gonnelli M, Retelletti Brogi S, et al. DOM dynamics in open waters of the Mediterranean Sea: new insights from optical properties[J]. Deep Sea Research Part Ⅰ: Oceanographic Research Papers, 2019, 144: 95-114. DOI:10.1016/j.dsr.2019.01.007
[41] Osburn C L, Mikan M P, Etheridge J R, et al. Seasonal variation in the quality of dissolved and particulate organic matter exchanged between a salt marsh and its adjacent estuary[J]. Journal of Geophysical Research: Biogeosciences, 2015, 120(7): 1430-1449. DOI:10.1002/2014JG002897
[42] Yamashita Y, Cory R M, Nishioka J, et al. Fluorescence characteristics of dissolved organic matter in the deep waters of the Okhotsk Sea and the northwestern North Pacific Ocean[J]. Deep Sea Research Part Ⅱ: Topical Studies in Oceanography, 2010, 57(16): 1478-1485. DOI:10.1016/j.dsr2.2010.02.016
[43] Romero C M, Engel R E, D'Andrilli J, et al. Compositional tracking of dissolved organic matter in semiarid wheat-based cropping systems using fluorescence EEMs-PARAFAC and absorbance spectroscopy[J]. Journal of Arid Environments, 2019, 167: 34-42. DOI:10.1016/j.jaridenv.2019.04.013
[44] Gonçalves-Araujo R, Stedmon C A, Heim B, et al. From fresh to marine waters: characterization and fate of dissolved organic matter in the Lena River Delta Region, Siberia[J]. Frontiers in Marine Science, 2015, 2. DOI:10.3389/fmars.2015.00108
[45] Wen Z D, Song K S, Shang Y X, et al. Differences in the distribution and optical properties of DOM between fresh and saline lakes in a semi-arid area of Northern China[J]. Aquatic Sciences, 2018, 80(2). DOI:10.1007/s00027-018-0572-5
[46] Butturini A, Herzsprung P, Lechtenfeld O J, et al. Dissolved organic matter in a tropical saline-alkaline lake of the East African Rift Valley[J]. Water Research, 2020, 173. DOI:10.1016/j.watres.2020.115532
[47] Xu L C, Liu Y, Sun Q L, et al. Climate change and human occupations in the Lake Daihai basin, north-central China over the last 4500 years: a geo-archeological perspective[J]. Journal of Asian Earth Sciences, 2017, 138: 367-377. DOI:10.1016/j.jseaes.2017.02.019
[48] Zhang Y X, Cheng D D, Ren Y X, et al. Influence of land cover types and phytoplankton community on the distribution and fate of dissolved organic matter in a typical river located in the semi-arid regions of China[J]. Journal of Hydrology, 2022, 610. DOI:10.1016/j.jhydrol.2022.127818
[49] Wei M J, Gao C, Zhou Y J, et al. Variation in spectral characteristics of dissolved organic matter in inland rivers in various trophic states, and their relationship with phytoplankton[J]. Ecological Indicators, 2019, 104: 321-332. DOI:10.1016/j.ecolind.2019.05.020
[50] 梁旭, 刘华民, 纪美辰, 等. 北方半干旱区土地利用/覆被变化对湖泊水质的影响: 以岱海流域为例(2000-2018年)[J]. 湖泊科学, 2021, 33(3): 727-736.
Liang X, Liu H M, Ji M C, et al. Effects of land use/cover change on lake water quality in the semi-arid region of northern China: a case study in Lake Daihai Basin (2000-2018)[J]. Journal of Lake Sciences, 2021, 33(3): 727-736.
[51] Wang S H, Xu C, Zhang W C, et al. Human-Induced water loss from closed inland Lakes: hydrological simulations in China's Daihai lake[J]. Journal of Hydrology, 2022, 607. DOI:10.1016/j.jhydrol.2022.127552
[52] 蓝学恒, 张翔宇, 张帆, 等. 岱海生物群落结构的演变及其对渔业发展的影响[J]. 湖泊科学, 2001, 13(2): 180-186.
Lan X H, Zhang X Y, Zhang F, et al. Evolution of biological community and fisheries development in Daihai lake, Inner Mongolia[J]. Journal of Lake Sciences, 2001, 13(2): 180-186. DOI:10.3321/j.issn:1003-5427.2001.02.013
[53] 吴东浩, 徐兆安, 马桂芬, 等. 内蒙古典型湖泊夏季浮游植物群落结构特征及变化[J]. 水文, 2012, 32(6): 80-85.
Wu D H, Xu Z A, Ma G F, et al. Characteristics and variation of phytoplankton assemblage in typical lakes of Inner Mongolia[J]. Journal of China Hydrology, 2012, 32(6): 80-85. DOI:10.3969/j.issn.1000-0852.2012.06.017
[54] 赵斌, 蔡庆华, 黎道丰, 等. 岱海水质咸化过程中营养状况的变化[J]. 水生生物学报, 2000, 24(5): 509-513.
Zhao B, Cai Q H, Li D F, et al. Preliminary study on the changes of trophic state during the process of water salinization in Daihai lake, China[J]. Acta Hydrobiologica Sinica, 2000, 24(5): 509-513. DOI:10.3321/j.issn:1000-3207.2000.05.018
[55] 彭宁彦, 戴国飞, 张伟, 等. 鄱阳湖不同湖区营养盐状态及藻类种群对比[J]. 湖泊科学, 2018, 30(5): 1295-1308.
Peng N Y, Dai G F, Zhang W, et al. Differences in nutrition condition and algae population in different areas of Poyang Lake[J]. Journal of Lake Sciences, 2018, 30(5): 1295-1308.
[56] Zhou Y Q, Davidson T A, Yao X L, et al. How autochthonous dissolved organic matter responds to eutrophication and climate warming: evidence from a cross-continental data analysis and experiments[J]. Earth-Science Reviews, 2018, 185: 928-937. DOI:10.1016/j.earscirev.2018.08.013
[57] Hu C K, Xu H, Shi S W, et al. Sedimentary organic matter molecular composition reveals the eutrophication of the past 500 years in Lake Daihai, Inner Mongolia[J]. Environmental Research, 2023, 227. DOI:10.1016/j.envres.2023.115753
[58] 张雨晴, 邵克强, 胡洋, 等. 岱海水体及沉积物细菌多样性及群落组成特征[J]. 湖泊科学, 2022, 34(6): 2070-2082.
Zhang Y Q, Shao K Q, Hu Y, et al. Bacterial diversity and community composition in lake water and sediment of Lake Daihai[J]. Journal of Lake Sciences, 2022, 34(6): 2070-2082.
[59] 姜加虎, 黄群. 我国西部地区湖泊水资源利用与湖水咸化状况分析[J]. 干旱区地理, 2004, 27(3): 300-304.
Jiang J H, Huang Q. Analysis on utilization of the lacustrine water resources and the Salinization of lacustring water in west China[J]. Arid Land Geography, 2004, 27(3): 300-304. DOI:10.3321/j.issn:1000-6060.2004.03.004
[60] Cortes-Tolalpa L, Norder J, van Elsas J D, et al. Halotolerant microbial consortia able to degrade highly recalcitrant plant biomass substrate[J]. Applied Microbiology and Biotechnology, 2018, 102(6): 2913-2927. DOI:10.1007/s00253-017-8714-6
[61] Xu W, Gao Q, He C, et al. Using ESI FT-ICR MS to characterize dissolved organic matter in salt lakes with different salinity[J]. Environmental Science & Technology, 2020, 54(20): 12929-12937.
[62] 刘文. 青藏高原北部湖泊有机质构成与微生物降解过程及其对盐度响应的研究[D]. 武汉: 中国地质大学, 2020.
Liu W. Study on organic matter composition and microbial degradation in response to salinity in Northern Qinghai-Tibetan lakes[D]. Wuhan: China University of Geosciences, 2020.