Environ Earth Sci (2017) 76:142 DOI 10.1007/s12665-017-6427-x ORIGINAL ARTICLE Influence of sediment DOM on environmental factors in shallow eutrophic lakes in the middle reaches of the Yangtze River in China 1,4 1,2 1,3 1 1 Yiwen Wu • Yingjie Li • Jingjing Lv • Beidou Xi • Lieyu Zhang • 1,4 1 1 1,4 Tianxue Yang • Guowen Li • Caole Li • Hongliang Liu Received: 23 March 2016 / Accepted: 17 January 2017 / Published online: 10 February 2017 Ó Springer-Verlag Berlin Heidelberg 2017 Abstract Both three-dimensional excitation–emission environments. Components C1, C2, and C4 were correlated matrix fluorescence spectroscopy and parallel factor anal- positively with PC1 axis (factor 1), while C3 was opposite. ysis were utilized to identify dissolved organic matter Component C1 and C3 showed positive correlations with (DOM) components in sediments of thirty eutrophic shal- PC2 axis (factor 2). The CCA and Pearson correlation low lakes in the middle reaches of the Yangtze River in analysis showed that sediment DOC was correlated sig- China. Four distinct DOM components were identified: two nificantly with sediment variables (TN, OM, and conduc- 3- main components regarding terrestrial humic-like materials tivity), water quality variables (TN, PO4 , and Chl a), and (C1 and C2), one about terrestrial fulvic/humic-like mate- DOM components C1 and C3. All DOM components were rials (C3), and one related to autochthonous tryptophan- related significantly to different environment variables, like materials (C4). The dominance of terrestrial fluores- including water quality variables especially nutrient ele- - cence materials in DOM indicated that terrestrial inputs ments (NO3 , TN, Chl a, and DOC) and sediment variables ? have critical effects on the surveyed lakes. The Principal (OM, NH4 , and HCl–P). The relationship between DOC Component Analysis (PCA) and Canonical Corresponding and the lake comprehensive nutritive index TLI was mar- Analysis (CCA) were applied to analyze DOM components ginally significant. and their relationship with the environmental variables. PCA graphs showed that there were spatial differences in Keywords DOM Á Environmental variables Á PCA Á CCA Á DOM fluorophores among lakes with various Shallow eutrophic lakes & Beidou Xi Introduction [email protected] & Lieyu Zhang As the largest substance pool in lake ecosystems, sediment [email protected] receives organic matter (OM) primarily from terrene and 1 State Environmental Protection Key Laboratory of residues of aquatic organisms (Zhu and Chen 2001). Dur- Simulation and Control of Groundwater Pollution, Chinese ing the process of organic matter mineralization, a large Research Academy of Environmental Sciences, amount of oxygen was consumed, and nutrient elements No. 8 Dayangfang, Beiyuan Road, Chaoyang District, such as carbon (C), nitrogen (N), phosphorus (P), and Beijing 100012, People’s Republic of China 2 sulfur (S) were released into water column, which could College of Resource and Environmental Engineering, cause serious deterioration of water quality (e.g., water Wuhan University of Technology, Wuhan 430070, People’s Republic of China eutrophication) (D’Angelo and Reddy 1994). In deep lakes, 85% of the OM was oxidized before it reached the ther- 3 School of Energy and Environment, Zhongyuan University of Technology, Zhengzhou 450007, People’s Republic of China mocline (Eadie et al. 1984) and the organic particles in deep lake sediments were not necessarily proportional to 4 CNHOMELAND Environmental Protection Water Pollution Governance Academician Workstation, Guangzhou 510000, those in the surface water, so the influence of OM on water People’s Republic of China quality in deep lakes is not critical (Xu et al. 2015). But in 123 142 Page 2 of 13 Environ Earth Sci (2017) 76:142 shallow lakes, there is no thermocline, and the substance River region have been under mesotrophic or eutrophic can be readily released from sediment to overlying water conditions (Wang et al. 2005a). Previous studies focused by wind, waves, and bioturbation (Kenney et al. 2016). mainly on the eutrophication process in one or two lakes in Thus, the OM in sediments plays an important role in this region. However, the trophic status in many other lakes controlling biogeochemical processes and influencing of this region is still poorly understood, and we know less water pollution in shallow lakes. about how DOM composition varies spatially across the As an active part of the OM, dissolved organic matter different lakes and what abiotic factors determine the (DOM) is comprised of a series of OM which could dis- spatial DOM variation in the Yangtze River region. As the solve in water and pass through 0.45 lm filter membrane aims of this study were: (1) to investigate the trophic status (Kalbitz et al. 2000). DOM includes organic acids carbo- of the shallow lakes in the middle reaches of the Yangtze hydrates, free amino acid, humic substances, phenolic, River region; (2) to analyze the sediment DOM compo- carbonyl, enzymes and so on (Hur et al. 2011; Jones and nents in eutrophic lakes using EEMs–PARAFAC method; Bryan 1998). DOM played important roles in influencing (3) to determine the relationship between environmental global C, N, and P bioavailability (Inamdar et al. 2012), variables and sediments DOM in the lakes of Yangtze altering metal speciation and transportation (Louis et al. River region. 2014; Neculita et al. 2011), and accepting electrons from microbial respiration (Lovley et al. 1996) in lake ecosys- tems. Residues and metabolites of microorganisms such as Methods phytoplankton and bacteria in water column provided the autochthonous resources for DOM in sediments (Birdwell Sample origin and Engel 2010), while terrigenous materials such as plants’ residues and humic substances are the allochtho- Ninety water samples and sixty sediment samples were nous inputs for DOM components (Li et al. 2015). Sedi- collected between August and September in 2014 from ments seems to be the main place for producing DOM thirty shallow lakes (GPS coordinates: 108°210–116°070 E, components, and the complexing ability of humic acid 29°050–33°200 N; waterbody size [10 km2; Fig. 1; from sediments was much stronger than those from waste Table 2) in Hubei Province, which is located in middle water (Ghosh and Banerjee 1997). These components course of the Yangtze River. This region has subtropical could enter the overlying water from sediment by water monsoon climate, with average annual temperature of upwelling, diffusion, and gas bubbles rising (Malmqvist 16 °C. The investigated lakes are located along Han River and Maki 1994). DOM might also precipitate from the and the Yangtze River. Palm red soil, yellow–brown soil, water column into the sediments (Ward 1994), and this and paddy soil are the main bottom types in the middle processes might occur more often in eutrophic freshwater course plain of the Yangtze River (Wang and Dou 1998). systems (Thomas 1997). Phytoplankton assemblages in the lakes were composed Three-dimensional excitation–emission matrix (EEM) mainly of Anabaena flos-aquae, Merismopedia glauca, fluorescence spectroscopy combined with parallel factor Microcystis aeruginosa,Cyclotella hubeiana, Synedra acus, analysis (PARAFAC) has been widely used to analyze the Cryptomonas ovata, etc.(Yan et al. 2015). Zizania aquatica DOM from numerous types of freshwater system in recent L, Potamogeton distinctus, Hydrilla verticillata, Nelumbo decade (Birdwell and Valsaraj 2010; Carstea et al. 2014). nucifera were the common aquatic macrophytes in these Fluorescence spectroscopy can provide sufficient infor- lakes (Wang and Dou 1998). mation on DOM source and composition with only small amount of sample and little sample isolation or preparation Water and sediment collections and physiochemical (Coble 1996; Birdwell and Valsaraj 2010; Guo et al. 2014). analysis PARAFAC is a powerful statistical method, which can effectively decompose fluorescence EEMs into different The water samples were taken from 0.5 m below the water independent groups of fluorescent compounds (Singh et al. surface by a 1.0 L plastic water sampler, and the surface 2010). Thus, utilization of both EEM and PARAFAC could sediment samples were collected by a 1/16 Peterson give a better understanding of DOM characteristics in the dredger. In the field, pH and dissolved oxygen (DO) in sediment of shallow lakes. water column were measured by the YSI ProDSS (digital Due to the economic and social development in the sampling system) handheld multiparameter meter (YSI- Yangtze River region, a lot of nutrient elements associated 556MPS, YSI) and water transparency (Sacchi depth, SD) with sewage waste were anthropogenically released into was measured by the Sacchi disk. Water and sediment the rivers and lakes in the Yangtze River region. Most of samples were kept at 4 °C and taken immediately to the the lakes in the middle and lower reaches of the Yangtze laboratory for chemical analysis. Then, sediments samples 123 Environ Earth Sci (2017) 76:142 Page 3 of 13 142 Fig. 1 Map of the thirty surveyed lakes in Hubei Province. Lake number-name: 1-Bao’an Lake, 2-Baoxie Lake, 3-Ce Lake, 4-Chidong Lake, 5- Chong Lake, 6-Daye Lake, 7- Dongxicha Lake, 8-Futou Lake, 9-Hanyang Dong Lake, 10- Hong Lake, 11-Hou Lake, 12- Huama Lake, 13-Liangzi Lake, 14-Longgan Lake, 15-Lu Lake, 16-Niulang Lake, 17-Niushan Lake, 18-San Lake, 19-Sanshan Lake, 20-Shangjin Lake, 21- Shangshe Lake, 22-Taibai Lake, 23-Tangxun Lake, 24-Tongjia Lake, 25-Wu Lake, 26-Xiliang Lake, 27-Yezhu Lake, 28- Chang Lake, 29-Zhangdu Lake, 30-Zhupo Lake were freeze dried and filtered through 100 lm meshes 0.45 lm glass fiber filter (Whatman GF/F, burned at sieve in the laboratory, and stored at 4 °C for later use. 450 °C for 4 h) for later analysis. The dissolved organic In laboratory, chlorophyll a (Chl a) in water samples carbon (DOC) content in DOM leaching liquor (sedi- was determined using 90% of the hot ethanol extraction ments: water 1:10) was determined by a total organic method (Papista et al.