Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | p < ), specific UV absorbance 1,2 250 : 365 E . In most sampling locations, CDOM a , and J. H. Ma 1 0.01). Principal component analysis (PCA) 5896 5895 ) indicated that CDOM in river waters had higher p < r S , J. Du 1 , Y. Zhao 1 , K. S. Song 1 ), and spectral slope ratio ( 254 This discussion paper is/has beenSciences under (HESS). review Please for refer the to journal the Hydrology corresponding and final Earth paper System in HESS if available. Northeast Institute of Geography andCollege Agroecology, CAS, of Changchun, Resource China and Environment, University of Chinese Academy of Sciences, aromaticity, molecular weight, and vascularFurthermore, plant results contribution showed that than DOC inproportion concentration, terminal of CDOM light waters. autochthonous absorption, sources andin of the CDOM other in freshwater plateauintense rivers waters were ultraviolet reported all irradiance in higherresponsible and than the for the landscape literature. above features phenomenon. The Redundancyenvironmental of strong analysis variables TSM, (RDA) Hulun evapoconcentration, TN, indicated and that Buir EC the characteristics, had plateau a followed strong by may correlation TDS with be and lightwas chlorophyll absorption the dominantalgal particles non-water often light-absorbing exceededthese substance. that optical-physicochemical correlations by Light is phytoplanktoninfluence absorption helpful in of in the by water the plateau quality evaluation non- environments. waters. of And factors Study the the on study of potential non-water on organicto light carbon global absorption in carbon plateau in balance lakes estimation. had cold a plateau vital contribution water (SUVA indicated that non-watermight be light the causes absorption ofCDOM the and absorption diversity of anthropogenic in water0.01). nutrient quality river Analysis parameters of waters disturbances in ratio of Hulun was absorption Buir at significantly plateau. 250–365 nm lower ( than terminal waters ( Abstract Spectral characteristics ofexamined in chromophoric conjunction dissolved26 with terminal organic environmental waters in factors matter(DOC), Hulun in total (CDOM) Buir the plateau, nitrogen were waters northeastterminal (TN), China. of waters and Dissolved 22 total than organic rivers carbon phosphorous rivers and (TP) waters were ( significantly higher in 1 2 Beijing, China Received: 30 March 2015 – Accepted: 21Correspondence May to: 2015 K. – S. Published: Song 22 ([email protected]) June 2015 Published by Copernicus Publications on behalf of the European Geosciences Union. Influence of environmental factors on spectral characteristic of chromophoric dissolved organic matter (CDOM) inMongolia Inner Plateau, China Z. D. Wen Hydrol. Earth Syst. Sci. Discuss.,www.hydrol-earth-syst-sci-discuss.net/12/5895/2015/ 12, 5895–5929, 2015 doi:10.5194/hessd-12-5895-2015 © Author(s) 2015. CC Attribution 3.0 License. 5 15 20 25 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) a ), are (chl cients, S a ffi ) and other λ ( erent aquatic ff (440) was loosely CDOM a CDOM a ) was used to track changes 250 : 365 erent conclusions due to regional concentrations was identified in the ff E ) and CDOM spectral slopes ( a λ concentration by remote image sensing a CDOM a 5898 5897 nm ( λ (300) and chl is dependent on the calculated wavelength intervals, and CDOM may also correlate with the ratio of fulvic acid (FA) to humic S a ect the temporal and spatial variation of CDOM, and some S ff ), as a dimensionless parameter, could avoid the limitations of r S concentration has received widespread attention. A significant a erent models were established based on this correlation in Lake ff ) was found to have strong correlation with DOM aromaticity as measured by 254 cients at specific wavelengths ffi Recent studies have proven that CDOM in aquatic ecosystems exerts an impact Spectral analysis of CDOM (absorption and fluorescence) has been used to trace CNMR spectroscopy (Weishaar et al., 2003); two optical parameters, the absorption correlations among them have beenfound established; between a dissolved significant positive organic correlation carbon was (DOC) and CDOM absorption coe spectral wavelength measurements (Helmsanalysis et of these al., spectral 2008;CDOM indices variations Spencer in was et the useful aquatic al., for environment. 2012). understanding The spatial andon temporal ecosystem productivity,(Zhang optical et properties al., 2007). ofunderstood However, regional water, in CDOM and characteristics diverseparameters are biochemical of aquatic still processes water not environments (Findlay thoroughly andhave because been Sinsabaugh, proposed 2003). of to Many various water a quality physico-chemical parameters the ratio of the slope ( and a series ofTaihu (Zhang et di al., 2007), thein Yangtze River (Zhang the et USA al., 2005), (Yacobi and etwhich the interferes al., Georgia with 2003). river the determination CDOM(Siegel of strongly chl et absorbs in al., theof 2005), blue CDOM therefore spectral with region, thelinear chl relationship relationship between between thecentral spectral eastern Mediterranean characteristics Basin (Bracchini etet al., al., 2010), 2006), the and Atlantic Ocean therelated (Kitidis Baltic to Sea (Kowalczuk pigment et al., concentrationsSea 2006), (Organelli in et but al., the 2014). 0–400 Furthermore,physico-chemical m parameters the depth relationship of between water, layer such(TP), of salinity, as and NW total extracellular enzyme nitrogen Mediterranean activities (Gonnelli (TN),2006; et total al., Niu phosphorous 2013; et Kowalczuk et al., al.,environments. 2014; However, these Phong studies etvariations reached al., in water di 2014), quality. were all investigated in di in the size of DOM(SUVA molecules (De13 Haan and De Boer, 1987); specificcoe UV absorbance 1 Introduction Chromophoric dissolved organic matter (CDOM) isorganic the colored component matter of dissolved contributed (DOM) by terrestrial in inputsexcretion, the and zooplankton river natural and dischargeaquatic in bacterial waters ecosystems coastal (Coble, metabolism waters. environment. 2007). Phytoplankton arelargest As CDOM an reservoir the important of major is constituentcarbon organic of CDOM principally carbon DOM, cycle sources which on (Gonnelli isCDOM in Earth, the et absorbs CDOM solar al., plays radiationshield 2013; a in biota vital Mopper the from role harmful UV andproperties in UV and Kieber, radiation, of the visible 2002). and ranges natural global itCDOM of More water is also the (Organelli influences largely importantly, the light responsible et inversion spectrum for accuracy al., of the to remote 2014). bio-optical sensing of The chlorophyll absorption characteristic of Xie et al.,understand 2014). DOM Understanding cycling in the aquaticabsorption ecosystem. spectral According of to characteristics previous CDOM of studies, oftenoptical the CDOM light decreases wavelength may in (Coble, help aproperties 2007; to near-exponential of Zhang manner et CDOM withdeveloped. The al., increasing from ratio of 2010). absorption absorption at In 250–365 spectra, nm ( order several to spectral characterize indices the have been universally recognized proxies ofet al., CDOM 2008). Furthermore, concentration and molecular origin (Helms its origin and chemical composition (Stedmon et al., 2000; Vodacek et al., 1997; acid (HA). In fact, the use of and other suspended solids (Siegel et al., 2005; Song et al., 2014). 5 5 10 15 20 25 10 20 15 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , and most of them are ff E). The average altitude of 0 4 ◦ ects on CDOM optical properties ff –126 0 12 ◦ 5900 5899 N, 97 0 23 ◦ –53 0 24 ◦ (37 2 Inner Mongolia Plateau in China is located in an arid and cold climate zone with In this study, we investigated CDOM in lakes and rivers in Inner Mongolia plateau Studies published to date have focused on the relationship between CDOM (Graeber et al., 2012;The Gueguen properties et of al.,due 2011; CDOM to Mavi the in et uniqueDOM plateau al., natural 2012; composition water environmental Song intwo at andand et Tibetan climatic high al., exhibited features 2013b). altitude alpine a ofCDOM have lakes these parameters high attracted in showed waters. biolability three interest The autochthonous a intermontane DOM of or plateau limited DOM rivers DOC derived terrigenous from inpool anthropogenic (Spencer western sources DOM (Spencer dominated US et the et indicated DOM factors that al., al., in 2012). 2014). plateaus However,physicochemical The the correlations area analysis is relationship critical has of of of CDOM for in been CDOM understanding plateau water to the less environmentsquality and source factors environmental evaluating on well and the non-water potential distribution light studied. influence absorption. of water Analysis ofsparse annual these rainfall. optical- vast The grasslands plateau and isare forest. covered These with supplied lakes numerous withnoncontributing are lakes lakes water surrounded located (Tao by by far etclimatic away al., precipitation factor from 2015). and in the Theproperties river arid ocean unique compared and runo with and geographical the environmentare cold bulk saline, and plateau which of allows inland regionset higher water. al., may carbon Moreover, 2008; storages over lead Song levels 80 et than %global to al., carbon fresh of balance 2013b). alterations water the estimation. The lakes in lakes plateau (Duarte lakes CDOM therefore play anwith important role the in followingcharacteristic variations objectives: of (1) CDOMarid characterization in regions; plateau (2) of rivers assessing the and the terminal distribution relationships waters between and in CDOM spectral cold optical and properties and the whole regionof is Hulun over Buir, 1000 XilinGol, m,reservoirs Ulanqab, and and Bayannur, other Alxa, it surface andcollected is water Erdos water areas basically samples plateaus. account a were for Rivers,characterized taken 0.8 lakes, plateau by % from a of landform Hulun typical the semi-humid Buir composed intensive and whole Plateau solar semi-arid area. (Fig. radiation continental All 1). monsoon throughout the climate This thewith with a year. plateau Hulun windy is spring, Buir a Plateaudry hot has winter. and distinct The rainless seasons plateau summer, aand is windy forests, dotted and and with short the numerous autumn, twoMongolia lakes and largest surrounded are a freshwater by cold located lakes vast (Hulun infilled grasslands Lake with this terminal and waters area. Buir due Lake) Most torivers the of lakes flow particular Inner through climate in Hulun and this geographic Buirand location. area Plateau, Several Zhadun including are Rivers. the inland Wuerxun Kerulen,north River Ergun, stagnant originates Wuerxun, and lakes Hailar, from empties Buirand Lake’s into finally northern Hulun into shore, the Lake. flows north Ergun Kerulen River. to The River join Zhadun the flows River Ergun east flows River. into through A the total Hulun Hailar of River, Lake, flowing 22 river waters and 24 terminal waters were relevant physico-chemical parametersof of CDOM water; to andstudy the (3) enhances total our evaluating understanding the non-waterconditions of in contribution light inland CDOM waters in absorption. variation aridcorrelation with and The analysis cold respect plateau information could to region. The contribute environmental obtainedsatellite optical-physicochemical to remote in improved sensing understanding imagery this in and this allow area. the use of 2 Material and methods 2.1 Study sites Inner Mongolia Autonomous Regionabout is 1.18 located million in the km north of China with an area of properties and environmentaland factors; watershed characteristics results all indicate have important that e salinity, solar radiation, 5 5 15 20 25 10 10 15 20 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | (1) (2) C). ) is ◦ 0 λ 2 ) was cients ( r ± S ffi CDOM a ered acetone ff ), the measured β cients (Bricaud et al., ) was calculated using cients at wavelengths ffi ffi ) (Weishaar et al., 2003). 1 − 250 : 365 E ) between wavelengths 275–295 nm values were calculated by dividing the . 254 350–400 ) was calculated from the measured water 400 440) were selected to express the CDOM S − 5902 5901 350 CDOM CDOM S and a a to 295 ) − cient ( λ 275–295 − ffi S 0 275 λ ( ) (3) S S λ /L ( e λ S · ) ) was extracted from water samples by 90 % bu 0 a OD OD λ · · ( ) is the CDOM absorption at a given wavelength, and V S 335) and 440 nm ( λ · ( (chl CDOM 2.303 a a CDOM = is the cuvette path length (0.01 m) and 2.303 is the conversion factor. = ) 2.303 CDOM 0 ) a L λ λ = ( ( is the average optical density. The absorption coe ) λ ( λ CDOM spectral slopes ( Particulate absorption was determined by quantitative membrane filter technique CDOM CDOM PB 335 nm (a where concentration (Miller, 1998). CDOMabsorbance absorption at ratio 250 nm ( and 365 nm. SUVA OD UV absorbance at 254 nm by the DOC concentration (mgL and 350–400 nm were bothto calculated the absorption using spectrum a according nonlinear to fit the Eq. of (2) ana (Bricaud exponential et function al., 1981; Jerlov, 1968). Where (QFT) (Cleveland andthrough Weidemann, 0.7 1993). µm Aabsorption glass of certain fiber total volume particulate membranespectrophotometer trapped of (Whatman, (Shimadzu, on water 2660) the GF/F filter wascorrection with 1825–047), membrane of filtered virgin was and the wet determined path the membrane by length UV as light with reference. path After length amplification factor ( optical densitiesaccording were to the Eq. transformed (3) (Bricaud into and Stramski, 1990). totala particulate absorption coe optical density (OD) following the Eq. (1). a 1981). The absorption coe Chlorophyll collected in this studyBecause Hulun with Lake respect and Buir toare Lake classified both are as watershed river connected water with characteristics samples rivers, and in and the lake the subsequent2.2 water size. analysis samples in this Water study. sampling and water qualityWater measurement samples wereduring taken September from 2012 (Fig. 46at each 1). sampling site The approximately sites surface 4within L water in 24 and h. (0.5–1 carried Hulun m) Chemical back sampleand Buir to and laboratory was physical Plateau, EC in collected parameters, a China, e.g., werequality portable analyzer pH, refrigerator determined (YSI6600, total US). dissolved inwith Concentrations solid of unfiltered sampling (TDS) DOC, water TN, sitususpended and samples TP matter by by were (TSM) measured a a2013a). Water standard was portable turbidity procedure determined (Turb) multi-parameter was(Shangfen, (APHA determined by 7230) water et by gravimetrical with a al., UV analysis Milli-Q 1998). spectrophotometer (Song water in Total 680 as et nm solution, reference al., and at the(Shimadzu, room UV-2600PC) by concentrations temperature the method (20 were detailed in determined Song et2.3 with al. (2013a). a Non-water light UV absorption analysis spectrophotometer CDOM was extracted fromglass the fiber membrane collected (Whatman, GF/F water 1825-047)0.22 samples and µm then by was polycarbonate filtering further filtered through through finished membrane a with (Whatman, 2 0.7 µm days 110606). inwas order analyzed The to within avoid 12 filtering alteration h byquartz throughout microbial process cuvette. UV-2600 activity. spectrophotometer CDOM was Absorbance absorption quipped scanswater using 1 were was cm performed used fromabsorbance as 200 at reference. to In 700 nm 800 order nm, was to and used Milli-Q eliminate to the correct internal absorption backscattering, the coe calculated as the ratio of the absorption at a reference wavelength (440 nm). The spectral slope ratio ( 5 5 25 10 20 25 15 10 15 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) a ). ). in 1 1 λ − ( 1 − − is the PB a S 0.63 mgL 0.01). Strong is the volume ± erent sampling V ff erence between p < ff ), and 2 cient was calculated using ffi ) was the di λ 0.001) and TP ( erence was found between river ff phy a p < cient ( ffi 5903 5904 ) was determined and calculated as the λ cient greater than 20. A Monte Carlo permutation NAP ffi a erence of DOC was also observed between these two ff 0.94). Regression analyses were also conducted, and = ) in river waters were both lower than in terminal waters, 2 1 R − ) (4) λ ). 0.82). ( 3 = 0.05). 2 NAP ≤ R ) according to the Eq. (4). a erences were observed for TN ( 0.001). The DOC concentration ranged from 8.44 to 39.74 mgL λ ff p ( − 0.04 mgL ) 0.50). The average nutrient concentrations for TN (1.33 ± ) is the total particulate absorption at a given wavelength (nm), λ p < ( NAP = λ ( a 2 PB a R PB a = ) ) and cient of non-algal particles ( 0.68). A positive correlation between DOC and TP was found in surface water in λ λ ( ffi ( = ective area of the deposited particle on the fiber membrane (m PCA was performed for all the sampling locations with ten water environment The above fiber membranes loaded with total particulate were soaked in the 2 PB phy ff a linear relationship between(Fig. EC 2b; and DOC was shown based on the collected data and TP (0.11 linear relationships were shown betweenR TN and DOC inthis Hulun area Buir (Fig. Plateau 2c; (Fig. 2c; variables (Fig. 3a).61.0 The % first of two theRelatively principal variability high components in loadings (PC)showed all on high of negative the PC1 the loadings. selected The(TN were PCA second and variables TSM explained PCA TP). (PC1, axis and Theseshowed revealed 36.4 gradients Turb, all %; high of whereas had negative PC2, nutrients positive loadings DOCwaters 24.6 loadings %). on and and on PC2. CDOM PC2. A terminalproximity Furthermore, clear to waters di TDS each (Fig. and otherexception chl 3b). of and one Terminal were point) in water distributedpositive Fig. side on 3b, samples of and PC2. the river clustered negative waters clustered in side almost of close exclusively on PC2 the (with the and significant di locations was assessed4.5 by for principal Windowswater component with quality analyses centered parametersRedundancy (PCA) and and analysis using (RDA) standardized light using CANOCO selected variables. CANOCO absorption 4.5, as Correlations characteristics and explanatory water between were quality variables. parameters determined The were by regression coe Further, the terminalThe waters positive relationship also betweenPlateau had DOC waters and higher (Fig. alkalinity 2a, alkalinity was and established in EC Hulun than Buir river waters. The contributions ofwater CDOM, light phytoplankton, absorption and atRetuerta 440 non-algal et nm al., particles were 2010). calculated (NAP) The using variation to Origin of non- water 8.0 quality software parameters (Ortega- in di 2.4 Statistical analysis The phytoplankton lighta absorption coe a SPSS 5.0. Becausethey the were responding first screened variables through Canonical maythe Correspondence variables Analysis exist (CCA) with in to an remove the inflation high coe autocorrelation, 3 Results 3.1 Water quality The collected riverquality and (Table 1). A terminal significant di water samples exhibitedriver large waters, variations and exhibited in higher water values in the terminal waters (23.03–300.5 mgL e test was conductedsignificantly and related indicated toreduced that light model, the absorption selected characteristics environmental (499 permutations variables under were the water types ( of the filtered water (m sodium hypochlorite solution in ordercoe to remove the pigments, and the light absorption Where 5 5 15 10 10 15 20 25 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) p > CDOM ), and a values 1 . There 275–295 1 − − m 1 nm − 350–400 3 − S 10 (335) and ), and the majority 1 × − nm CDOM 3 a 0.57 L mg C − ± 10 × 4.05 was clearly higher in river waters ± 254 3.48 in the river and terminal waters values in the river waters ranged from between 17.11–17.82 ± 19.25 = 254 in Hulun Lake were both lower than Buir Lake. 5906 5905 erence in the relative contributions of CDOM, 275–295 ff S (mean 350–400 1 S − erence between the two types of waters. Furthermore, ff nm and 2.30, and 8.02 3 ) ranges were both calculated as the indicators (Table 1). − 0.01). In order to confirm the source and composition of ± ) than the terminal waters (1.90 1 erence when compared with terminal waters. , and the mean SUVA ff − 10 1 p < − × m 275–295 350–400 1 m S − 1 − erent types of waters, the spectral slopes in the 275–295 nm (S to 26.79 ff values in the waters examined ranged from 5.43 to 20.73, and the 3 − values showed a wide variation in the river water samples ranging from diagonal), the more inhomogenous light contributions were observed (Fig. 5). 10 1.08 LmgC ◦ × ± 250 : 365 To assess the distribution of light absorption in the waters of Hulun Buir Plateau, E 275–295 in Fig. 4. There was no obvious di plotted based onlight the absorption numbers at of 440contributions sampling nm were using locations arranged a and from Pareto–Lorenzpoints their high curve are to contributions (Lorenz, represented low. to 1905). on Subsequently, theon the total The the cumulative abscissa relative vertical sampling axis, axis. and Theline more the (45 the cumulative curve contributions deviated plotted fromAccording the to theoretical the perfect Pareto evenness principle, theabscissa value of axis, vertical being axis was used incurve to accordance with interpret deviation 20 % the (Fig. Pareto- 5),substances Lorenz in it curves. Hulun was From Buir the Plateau observedthem, area degree that presented of CDOM inhomogenous the phenomena. absorption lightabsorption Among components. absorption was CDOM of light the absorption opticallywith by most 5.03 active 20 % % representative of of the the relativealgal samples cumulative corresponded particles to CDOM and contributions other phytoplankton,0.51 to % non-water 20 non-water of % absorption. cumulative of light Forwater the non- absorption absorption samples contributions, types, respectively. corresponded Thus, it withdominant for was compared all 1.46 observed with the and that non-algal non- CDOM particles and light phytoplankton. absorption was numerically levels of light absorption due to CDOM, phytoplankton and non-algal particles were and 350–400 nm (S S 14.80 phytoplankton and non-algal particles0.5). between At river all waters the andwater sampling terminal light waters locations, absorption ( the wasthe mean 52.78 % relative contribution with contribution of the2.01 CDOM of range up to non-algal varied to the particles from 97.13 totallight %. was 2.87 absorption non- Phytoplankton to on with absorption the 97.23 mean %, playedCDOM mean a was and 39.84 7.61 %, %. the minor dominant In ranging role non-water most light-absorbing from in water substance. total samples examined non-water in this study, mean values were 7.80 CDOM in di (440) both showed thatabsorption the than terminal river waters waters (Table exhibited 1). significantly higher CDOM light (2.74 this was significant ( 3.2 Spectral characteristics of CDOM CDOM absorption spectra ofas the waters collected the from Hulunultraviolet classical Buir to Plateau near-exponential decreased thespectra manner visible has with been spectralet increasing observed region. al., in wavelengths 2009; This many Xie fromof near-exponential et natural sampling al., the waters CDOM 2014). waters (Bricaud The absorption in et comparative the analysis al., was study, 1981; conducted and Spencer in the two mean types values of respectively. The majority1.09–3.56 of LmgC the SUVA of river waters in the study exhibited also showed no significantthe di mean values of was not a significant di 3.3 Light absorption of CDOM andDetailed particulates knowledge regarding thenon-algal relative contributions particles of to CDOM, theand phytoplankton total and biogeochemical non-water light models, absorption and are the essential in relative bio-optical contributions at 440 nm are shown 5 5 15 20 25 10 10 15 25 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ) is p < 335 1 ects − ff 275–295 S CDOM α 46). There 0.515, = = p n 6.64 mgL r ± 46). concentration. The = 0.05, a n p > 0.01, 46) and TSM ( p < ) (Fig. 6). = concentration. However, . The land use types around the n ff a 0.985, 275–295 concentration ( S 0.01, = were best correlated to light absorption of a p r a and chl ) between water quality and light absorption p < p 5908 5907 r 275–295 0.377, S cients ( = ffi p r . TDS, TP, and DOC were most closely corrected to CDOM a 46). Light absorption of pigments at 440 nm showed a significantly = cients between environmental variables with axes in RDA indicated n ffi 440) showed a significantly positive correlation with TN, TP, TDS, and DOC 0.01, and leaching, and can accumulate in terminal waters due to lower microbial 46), and there was also no linear relationship with chl ff = p < CDOM n 0.01), but had no correlation with chl α The Pearson correlation coe Many monitoring data indicate that DOC concentration in rivers shows a tendency to p < 4 Discussion 4.1 Dissolved organic carbon in riverPrevious and studies terminal waters showed thatwith DOC concentrations the in inlandphotobleaching in waters prolongation humid always regions decrease (Curtiswith of and long Adams, water 1995). water residence However,this terminal times study. waters exhibited residence The higher most DOCis likely values times explanation that than for the the the due riverin most opposite waters pattern refractory semi-arid in to of DOC regions DOMthe is concentration biodegradation (Song diluted terminal et in and al., waters(Table humid 1). 2013b). The regions compared sodicity and Further, of with waterconcentration) evapoconcentrated the could would river also result higher increase in waters DOM alkalinity decreased solubility. osmotic may Increasing and potential, EC which EC explain (salt has in negative the e inverse pattern on microbial activity (Mavi etvia al., runo 2012). DOM along withactivity. other Furthermore, nutrients the come average from DOC soil concentration in rivers (25.99 obviously higher than inet rivers al., reported 2012, in 2010). DOC othercharacteristics levels studies in (Jiang (Song rivers et are et al., linked al., 2014).rivers to The 2013b; climate could elevated Spencer and DOC be watershed concentrations landscape attributedthe in to these arid plateau evaporation, environment which ofis would Inner located be Mongolia in expected Plateau. semiarid toplateau Furthermore, climatic be waters Inner zones extreme Mongolia mainly with in region lowsampling depended rainfall, locations on and were surface mainly thethe runo grassland impoundment waters and of highlights forest. these the The organic-rich high nature DOC of these concentration ecosystems. in increase year by year, potentiallyet due al., to 2007). acid depositionconcentrations DOC (Evans are concentrations et high, and al., in increase 2005; surface as Monteith acidic water anion are concentrations decrease depressed (Evans when acid anion 3.4 Correlations between water quality parametersThe and RDA light absorption data showedthe that variability the of forward light selected absorptionof characteristics explanatory 0.781 with variables (Fig. species-environment could correlations light 6). explain absorption The characteristics of first2, all two the 9.4 %). axes collected water Coe of samples RDA (axis 1, explained 34.3 43.7 %; % axis of totallight variability absorption in (Fig. 6). TSM, TN, and chl characteristics presented in Table 2 indicate that CDOM light absorption ( that TSM, TN, andfollowed by EC TDS had and a chl strong correlation with light absorption characteristics, phytoplankton, non-algal particulates, and totalpH particulates were at related 440 to nm (Fig. the 6). CDOM EC spectral and slope ( and ( presented a significantlywater positive ( correlation with DOC, pH, and EC in this plateau positive correlation with TN ( was also no correlation between 0.01, light absorption ata 440 significant nm positive of correlation with total TSM particulates ( and non-algal particulates both had 5 5 10 20 15 25 10 15 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , = 2 2 R erent ff erent lakes ff mean values in 30 US ect the respiration and ff 0.001) (Lapierre and del p < 250 : 365 shown in Fig. 3a indicated that E a 0.34, = 2 r erent sampling locations. ff values indicate a decrease in aromaticity and 5909 5910 for the tracking of changes in CDOM molecule 250 : 365 E 250 : 365 E ) (Song et al., 2013b). Researchers reported that the structure 1 − 1000 µscm from the waters. TN and TP concentrations could a > 2 PCA was performed in order to explain the variations in water quality in the di Relationship between CDOM properties and nutrients (TN and TP) may be used showed that whenlinear TP regressions concentrations on were log-transformed data at ( very low level, DOC and TP fitted rivers ranged from 5.00 to 6.50 (Spencer et al., 2012), and in the Elizabeth River and were grassland andrelationship forest between with TN high andforested nitrogen DOC wetlands and in was the organic also Shibetsuof shown watershed, matter Japan during 14 content. (Jiang rainfall et A boreal in al., similar 2014). agricultural and Investigations and temperate regions of Québec (Canada) with 198 di which could have aorganic pronounced matter influence (Findlayinvestigation on and and the Sinsabaugh, statistical analysis relationship 2003). to between This verify it nutrient speculation further. and needs more data molecular weight (MW) ofin CDOM, river and waters thelow had results CDOM higher of MW aromaticity thisMW in and study CDOM terminal MW showed were waters than destroyed thattime implied by terminal CDOM and photolysis that irradiation. waters. with In chromophores The the terminalCDOM associated prolongation relatively waters, caused with of the change hydraulic by high of retention Furthermore, bond molecular previous cleavage, structure studies in resulted showed high that in MW the its bulk of transformation to a low MW pool. to track thenutrients plant-derived (TN source. and TP) StrongFig. and linear 2d). DOC The in relationships types theto were of surface land shown waters the use of between around nutrition Hulun the Buir levels water Plateau sampling in (Fig. locations 2c, may the be a waters. crucial The main land types in Hulun Buir Plateau 0.50). A positive correlation between DOCcentral and Alberta, EC was Canada also (Curtis reportedMongolia in and Plateau semi-arid are Adams, east- saline lakes, 1995). and Morehigher. the salinity than in Prior 80 the % collected research waters ofconcentrations was lakes generally has of in DOC shown Inner of in that DOC semi-arid in inland various region watersregions saline (Arts were in found China et lakes to (Song increase al., et always with al., 2000). salinity 2013b). contain in Also, semi-humid/semi-arid higher concentrations Giorgio, 2012). We suspect that theseof relationships CO may be connected withreproduction the of escape microbes and phytoplankton leading to the conversion of DOC to CO sampling waters (Fig. 3).be involved From in the the locationsdistinguishes non-water particulate light of light absorption, the absorption which from variablespositive may CDOM loadings in be light on one absorption. Fig. PC2 important TN indicated 3a,disturbance. and factor that The PC1 TP that PC2 close with could may juxtaposition be of related TDS to and anthropogenic chl nutrient 4.2 Analysis of CDOM spectral characteristic Terminal waters exhibited significantly higher(Table CDOM light 1). absorption Terminal thanvalue river waters waters ( in the study were almost brackish watersize with has high been EC Song practically et al., demonstrated 2013b). by Increasing many researchers (Helms et al., 2008; and composition of DOMRobarts, alters 2000). obviously The after use flowing of into saline lakes (Waiser and TDS concentration may be linked to phytoplanktonthat metabolism. The non-water PCA light also indicated absorptioncauses of and the anthropogenic diversity nutrient of water disturbance quality might in di be the et al., 2005). The responsein of the water alkalinity parameters to measurements.and acid In alkalinity deposition this would indicated study, bePlateau that the apparent waters an positive for relationship empirical estimating betweenby DOC model DOC a storage might based comprehensive be on dataset.salinity, established water which Within alkalinity, in could with semi-arid Hulun calibration reflectaccumulation regions, Buir the (Curtis DOC water was and residencebetween always Adams, times DOC related 1995; and and to Song dissolved EC et organic was al., matter established 2013b). based A on positive the correlation collected data (Fig. 2b; 5 5 25 25 20 20 10 15 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1 × − m 1 values 275–295 − S S revealed that the 254 and hydrophobic organic ), an indicator of CDOM 0.84) than other plain rivers R 254 S ± values in this study indicated S values indicate that the aquatic systems 1.47, 7.38 ± 254 could be used as indicator for terrigenous values contained greater allochthonous and 5912 5911 in the Songnen Plain waters ranged from 2.3 R S 254 values with the production of low MW CDOM. Two values were always comparable to HPOA, and the (Spencer et al., 2010). A possible driver of this 275–295 C-NMR (Weishaar et al., 2003). In this study, the S 1 ) (Spencer et al., 2012), and the Congo River (12.34 − 254 13 values (9.05 1 m − 1 250 : 365 − E values indicated that the organic matter in aquatic systems nm 3 values have been proven to have a correlation with DOM − 250 : 365 254 values. The intense solar irradiance in this region potentially E 10 2.8 SD) (Song et al., 2013b), in the tropical Epulu river ranged 254 ± × measurements in terminal waters indicated that the aromatic moieties values in 30 US rivers examined ranged from 1.31 to 4.56 LmgC 250 : 365 E 254 254 values in the river waters in this study were lower than the following rivers: ) (Spencer et al., 2009), which indicated the proportion of autochthonous 1 254 − nm 3 − ect of photodegradation and microbial degradation with prolonged water residence 0.14 SD) to 8.7 ( The majority of river waters in the study exhibited significantly higher SUVA ff ± sources CDOM and photolysisthan of allochthonous freshwater CDOM in rivers.molecular plateau The weight waters was and ratio higher that source of river (Helms water spectral et samples slopes al., with 2008; ( lower Spencer et al., 2010), indicated 10 values than allochthonous-dominated freshrivers (13.00–16.50 waters which include the majority of US higher MW DOM than terminal waters. Previous studies have proven that were inversely proportionaldecreasing to aromaticity, and a CDOM shallower spectral MW,content slope with signifing (Gonnelli an et a increasing aromatic al., steeper 2013; spectral Helms slope et signifing al., 2008). DOC percentage in bodiesthe of percentage of water terrigenous (Gonnelliknown DOC et geological is al., history higher of 2013). in thethe Our Hulun region, Halaha results Lake Buir river than Lake and indicate Buir is outflowpattern that from a Lake. in the throughput From Buir Wuerxun lake the river with Lakeaccepts to inflow watersheds the Hulun from shows Lake. Wuerxun potential Also, River the desertification.the flowing land Kerulun Hulun use from River. Lake Buir Natural notin Lake, grassland only but Hulun with also Lake the receives fresh watersheds.account the The organic for the water rich geographical larger from layers location percentage was and of dominant terrigenous land DOM use in Hulun pattern Lake. together that the percentage of highin MW Buir humic Lake, acid whereas inthe the CDOM reverse proportion in trend. of Hulun fulvic Lake Furthermore, was acid greater and than aromatic compounds showed waters, and thewaters. high Shorter residence MW time DOM offlow DOM was water in river shortened more waters the and abundantphenomenon photo-oxidation the (Song of quick in et exchange DOM, al., fresh rates which of 2013b; waters could Spencer et be than al., responsible 2012). terminal for the contribution of vascular plant matter to DOM in rivers might be greater than the terminal mean SUVA CDOM characteristic indegradation these and photobleaching plateau with strong rivers plateau ultraviolet2014, radiation is (Spencer 2009). et coupled al., SUVA evapoconcentration, photo- rivers in thealso intermontane presented plateaus higher of(Spencer the et western al., 2012). US with intense solar irradiance ( from 3.08 to 3.57 L mg C aromaticity as determinedlower by SUVA of CDOM ine this environment weretimes. lower From compared the within conclusions river of some waters studies due on to SUVA the was dominated by allochthonouset sources with al., significant 2007; vascular plant Spencer inputs et (Cory al., 2012). In this study, the SUVA Chesapeake Bay estuary rangedwith from the 4.33 reported to riverhigher 6.23 waters, mean (Helms the et plateauenhances al., rivers the photochemical 2008). in degradation Compared the of allochthonouscausing study DOM an presented and increase high in significantly MW the CDOM, (Spencer et al., 2012), while SUVA acid fraction (HPOA), the SUVA conjecture could be reached that lowwith SUVA little vasculardominated plant the input, organic and matterConversely, high content the SUVA (Spencer autochthonous et sources al., 2008; (algal Weishaar or et microbial) al., 2003). 5 5 10 15 20 25 15 20 25 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | concentration a cients and TN, TP, and and chl ffi 275–295 S concentration. The significant positive a 5914 5913 erent catchment properties and water quality ff ect the agglomeration or dissociation of particles ff n et al., 2011), the Epulu river (Spencer et al., 2010), as well as many ffi Pareto–Lorenz curve analysis indicated that in Hulun Buir Plateau and the similar substances might be estimated basedcontributions on in these this absorption study. valuestype Then and and the evaluate the regional cumulative estimated homogeneity value of non-water could light be absorption. used to identify water geographical aquatic environment,water we samples could to randomly analyze select the 20 % light of absorption, the the collected contributions of optically active parameters could bewaters. responsible Other for studies the havewater (Sieczko shown variation and Peduzzi, that 2014). in EC CDOMshowed values optical a in absorption rivers classification wide was and range, lakes of related whichand of Hulun CDOM may to these Buir a in Plateau the the EC waterslocated and near of indirectly the influence paddy lighthuman filed absorption. activities and (Graeber In built-up et addition, al., areas, in 2012). water lakes quality is greatly influenced by Plateau lakes with higherstudies salinity also may be showed responsibleof that for phytoplankton light this absorption in phenomenon.Frenette Previous by shallow, et non-algal inland al., 2003). particles lakesdominant In often and most light-absorbing exceeds water coastal substance samples that due waters even examined to when in (Carder photobleaching this the in et study, summer.(approximately CDOM CDOM al., The 50 % was absorption large 1991; at the contribution was 440 of nm(Parslow minimal et in CDOM al., the to 1998). surface total The layer) large absorption was contributionenvironments, of also such CDOM shown as was in also a the identified fluvial(Bricaud in Sepik lake other et River water (Frenette al., et 2002), and al., theindicated 2003), Ligurian that the Sea the equatorial (Organelli waters et Pacific in al.,in area Hulun all 2014). Buir the The Plateau water above were analysis samples Case-2 (Morelof water and surface with Prieur, waters CDOM 1977). (Prieur According present and toand Sathyendranath, the 1981), terminal optical the water classification majority samples of inwater, the Hulun and collected Buir river others Plateau could were be “NAP-type”. classified Di as “CDOM-type” At all the samplingnon-water light locations, absorption phytoplankton (Fig. absorption 4). played The a low minor levels of role phytoplankton on in total the Hulun Buir had no correlation;(BOUSSOLE a site) and similar the Mediterranean phenomenon2010; Sea has (central Organelli eastern been et basin) (Bracchini identifieddid al., et not al., in 2014). originate the These entirelythat results Ligurian from terrestrial the indicated input Sea and release that microbial andand CDOM activities dissociation properties all in of play of the an naturalFurthermore, important phytoplankton, CDOM waters strong role and solar (Ogawa in radiation the et inthe generation the al., photobleaching plateau 2001; area of and Rochelle-NewallCDOM. CDOM, the Inner and open resulting Mongolian ocean Fisher, in enhanced Plateaulakes 2002). variation has in in high the region levels theshrinkage of have structural shrunk and wind composition remarkably resuspension and in of of dust,influence recent lakes and the decades as a (Tao optical a et number characteristicscorrelation result al., of between and of 2015). light The climatic chl absorption conditions withHulun may TSM Buir Plateau seriously may with be alternating relatedto of to be windy, the rainless, further and unique studied. frigid climate conditions, of which need 4.4 Contribution of CDOM to light absorption 4.3 Correlations between water quality parametersStrong and positive light absorption correlations betweenDOC CDOM concentrations absorption in all coe waterbe samples indicated explained that by CDOMPrevious variations light absorbance studies in could have nutrients shownused and that as DOC CDOM an concentration absorption proxybasin to in for (Gri a a DOC range greater inUS of extent. many rivers spectra (Spencer inland could et water be in al., bodies, 2012), the including and aquatic our the environment results Kolyma of once river again Hulun support Buir this Plateau. relationship 5 5 25 20 15 10 10 15 20 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ect on CDOM properties in the waters of Hulun Buir ff a cients of living phytoplankton and ffi 5916 5915 in the presence of productivity degradation products, J. Geophys. a This study was financially supported by the National Natural Science 0.01). The non-water light absorption and anthropogenic nutrient p < erence in water quality was observed between river and terminal waters in Hulun nonalgal biogenousSargasso matter: Sea, Limnol. a Oceanogr., 35, comparison 562–582, 1990. betweensubstance) the in the Peru UV and upwelling visible domains, area Limnol. Oceanogr.,JGOFS-equatorial 26, and Pacific 43–53, program: 1981. a the contribution toDeep-Sea the Res. knowledge Pt. of II, the 49, equatorial 2583–2599, system, doi:10.1016/S0967-0645(02)00049-8, 2002. for quantifying chlorophyll Res.-Oceans, 96, 20599–20611, 1991. scattering correction for galss-fiber filters, Limnol. Oceanogr., 38, 1321–1327,402–418, 1993. , doi:10.1021/cr050350 2007. of fulvictransformations, acids J. Geophys. from Res., 112, G04S51, Arctic doi:10.1029/2006jg000343, 2007. surfacefreshwater waters: and microbialdoi:10.1007/bf02181040, contributions saltwater 1995. and lakes photochemical in east-centralof concentration and Alberta, molecular size ofWater Biogeochemistry, dissolved Res., organic 21, carbon 30, 731–734, in 1987. humic 59–76, Laken Tjeukemeer, Lange, H. J.: The attenuationof of wetlands ultraviolet and radiation lakes in on high the dissolved northern organic Great carbon Plains,analysis waters Limnol. of Oceanogr., CDOM 45, spectral slope 292–99, in 2000. eastern artificial and Mediterranean natural samples: Basin, an2010. application Aquat. in the Sci., central 72, 485–498, doi:10.1007/s00027-010-0150-y, ff Bricaud, A., Morel, A., and Prieur, L.: Absorption by dissolved organicBricaud, matter of the A., sea (Yekkow Roesler, C. S., Parslow, J. S., andCarder, K. Ishizaka, L., Hawes, J.: S., Baker, Bio-optical K., Smith, studies R., Steward, during R., and the Mitchell, B.: Reflectance model Cleveland, J. S. and Weidemann, A. D.: Quantifying absorption by aquatic particlesCoble, – P. a G.: multiple- Marine optical biogeochemistry: the chemistryCory, of R. ocean M., color, McKnight, Chem. D. Rev., M., 107, Chin, Y.-P., Miller, P., and Jaros, C. L.:Curtis, Chemical characteristics P. J. and Adams, H.De Haan, E.: H. and De Dissolved Boer, T.: organic Applicability of light matter absorbance and quantity fluorescence as and measures quality from References Arts, M. T., Robarts, R. D., Kasai, F., Waiser, M. J., Tumber, V. P., Plante, A.Bracchini, J., Rai, L., H., Tognazzi, and A., de Dattilo, A., Decembrini, F., Rossi, C., and Loiselle, S.: Sensitivity Bricaud, A. and Stramski, D.: Spectral absorption coe 5 Conclusions Knowledge of CDOMplateaus properties areas is and not wellareas their conducted. with The relationship unique to dry environmental conditions environmental and of plateau factors cold in climates have an important e Foundation of China (No.Academy 41171293) of and Sciences the granted “One to Hundred Kaishan Talents Song. Program” of the Chinese and potential implicationswas conducted for in carbonnumerous Hulun cycling Buir non-contributing in plateau lakesinformation which on inland the with includes water water. quality several high andplateaus An CDOM freshwater regions. in salinity. Also river rivers intensive and it The terminal and providesand study waters insight climate study in into in cold CDOM and inland primarily arid properties water.di The linked provides following to conclusions water were quality obtained: (1) A significant plateau. Study of thepotential optical-physicochemical influence correlation of is watercold helpful quality plateau for factors evaluating water the on environments,remote sensing non-water and data light it of absorption plateau is inland in useful water. arid forAcknowledgements. and the understanding the satellite Buir plateau ( disturbance might be the(2) main CDOM causes in of river thethan waters wide in had range terminal higher waters of in aromaticity, water cold MW,to quality and and the arid parameters; vascular strong plateau plant regions evapoconcentration, and intense contribution features; other ultraviolet (3) fresh irradiance water Environmental and rivers variables due plateaulight TSM, landscape absorption TN, characteristics, and followed EC by had TDS and a Chl strong correlation with 5 5 20 30 10 15 25 25 10 20 15 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | ect of salinity, sodicity and texture, Sci. Total ff 5918 5917 ries, D. S., Vuorenmaa, J., Keller, B., Kopacek, J., and ff ected soils: e ff CO(2) vs. DOC relationship across northern landscapes, J. Geophys. p erent land uses, Hydrol. Process., 28, 5105–5121,, doi:10.1002/hyp.9996 ff erences in the lake n, C. G., Frey, K. E., Rogan, J., and Holmes, R. M.: Spatial and interannual variability of ff ffi Environ., 435, 337–344,, doi:10.1016/j.scitotenv.2012.07.009 2012. Substances: Ecology and Biogeochemistry, Springer, Berlin, 1998. Wilander, A., Skjelkvale, B. L., Je in thedoi:10.1016/j.marchem.2005.12.005, 2006. Baltic Sea fromdi season, salinity and chlorophyll, Mar. Chem., 101, 1–11, Vesely, J.: Dissolved organic carbon trends resultingchemistry, from Nature, changes 450, in 537–540, atmospheric doi:10.1038/nature06316, deposition 2007. nitrogen and phosphorus, in:by: Carlson, Biogeochemistry D. of A. H. Marine A., Dissolved Academic Organic Press, San Matter,,doi:10.4319/lo.1977.22.4.0709 Diego, edited 1977. 455–507, 2002. of real-time monitoringa of chromophoric water dissolved quality organicdoi:10.3390/s140711580, in matter 2014. fluorescence a sensor, large Sensors, shallow 14, lake 11580–11594, (Lakeorganic Taihu, matter China) by using bacteria, Science, 292, 917–920,, doi:10.1126/science.1057627 2001. absorption by chromophoric dissolved organic matter(BOUSSOLE (CDOM) site), in Deep-Sea the Res. NW Pt. Mediterranean I, Sea 91, 72–85,, doi:10.1016/j.dsr.2014.05.003 2014. Res., 117, G03015, doi:10.1029/2012jg001945, 2012. 209–219, 1905. dissolved organic matter in salt-a 2014. Variability of chromophoric organic matter inRes. surface Pt. waters II, of 53, the 1666–1684, Atlantic 2006. Ocean, Deep-Sea organic carbon: observations, possible137, causes 55–71, and, doi:10.1016/j.envpol.2004.12.031 environmental 2005. impacts, Environ. Pollut., Matter, Academic Press, Elsevier Science, USA, 2003. in a,doi:10.1023/a:1022133530244 2003. fluvial lake (Lakeenzymatic Saint-Pierre, activity. A biophysical St-Lawrence approachChem., to 182, River), understand 79–85, the, doi:10.1016/j.bpc.2013.06.016 marine 2013. Aquat. carbon cycle, Biophys. Ecol.,changed 37, the amount 77–85, headwater and streams, Sci. composition Total Environ.,2012. of 438, 435–446, dissolved, doi:10.1016/j.scitotenv.2012.08.087 organic matter indissolved Central organic matter European in theJ. Kolyma Geophys. River, Res., East 116, Siberia, G03018, observed using, doi:10.1029/2010jg001634 satellite 2011. imagery, dissolved organic matter inMarine Hudson Syst., Bay 88, and 423–433, Hudson, doi:10.1016/j.jmarsys.2010.12.001 Strait 2011. using parallel factorAbsorption analysis, spectral J. slopes andphotobleaching slope of ratios chromophoric dissolved as organic,doi:10.4319/lo.2008.53.3.0955 indicators matter, 2008. of Limnol. molecular Oceanogr., 53, weight, 955–569, source, and Factors controlling nitrogen andwatersheds dissolved with organic di carbon exports across timescales in two Miller, W. L.: Photochemical principlesMonteith, D. and T., experimental Stoddard, considerations, J. Aquatic L., Evans, Humic C. D., de Wit, H. A., Forsius, M., Hogasen, T., Mopper, K. and Kieber, D. J.: Chapter 9 – Photochemistry and the cycling of carbon, sulfur, Niu, C., Zhang, Y. L., Zhou, Y. Q., Shi, K., Liu, X. H., and Qin, B. Q.: TheOgawa, potential H., applications Amagai, Y., Koike, I., Kaiser, K., and Benner,Organelli, R.: Production of E., refractory dissolved Bricaud, A., Antoine, D., and Matsuoka, A.: Seasonal dynamics of light Morel, A. and Prieur, L.: Analysis of variations in ocean color, Limnol. Oceanogr., 22, 709–722, Lorenz, M. O.: Methods of measuring theMavi, concentration M. of S., wealth, Sanderman, Publ. Am. J., Chittleborough, Stat. D. Assoc., J., 9, Cox, J. W., and Marschner, P.: Sorption of Kitidis, V., Stubbins, A. P.,Uher, G., Upstill Goddard, R. C., Law, C. S., and Woodward, E. M. S.: Gueguen, C., Granskog, M. A., McCullough, G., and Barber, D. G.: Characterisation of colored Helms, J. R., Stubbins, A., Ritchie, J. D., Minor, E. C., Kieber, D. J., and Mopper, K.: Jerlov, N. G.: Optical Oceanography, OceanographyJiang, Series, R., 5, Elsevier, Hatano, Amsterdam, R., 1968. Zhao, Y., Kuramochi, K., Hayakawa, A., Woli, K. P., and Shimizu, M.: Kowalczuk, P., A. Stedmon, C.,Lapierre, and J.-F. and Markager, del S.: Giorgio, P. Modeling A.: Geographical absorption and environmental by drivers CDOM of regional Evans, C. D., Monteith, D. T., and Cooper, D. M.: Long-term increases in surface water dissolved Findlay, S. E. G. and Sinsabaugh, R. L.: Aquatic EcosystemsFrenette, Interactivity of Dissolved J. Organic J., Arts, M.Gonnelli, M., T., Vestri, S., and and Santinelli, C.: Chromophoric Morin, dissolved organic matter and J.: microbial SpectralGraeber, D., gradients Gelbrecht, J., of Pusch, M. downwelling T., Anlanger, light C., and von Schiller, D.:Gri Agriculture has 5 5 10 15 20 25 30 30 10 15 20 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | in turbid inland a 5920 5919 erent seasons, Environ. Sci. Pollut. R., 21, 7678–7688, doi:10.1007/s11356-014-2704-3 , ff spatial variability in dissolved organicbasin, matter Alaska, quantity Global and Biogeochem. composition Cy., 22, from GB4002, the, doi:10.1029/2008gb003231 Yukon River 2008. Dyda, R. Y.,Photochemical degradation of Mwamba, dissolved organic V. matterCongo and River, L., dissolved J. lignin Geophys. phenols Mangangu, Res.-Biogeo., from 114, the G03010, A. doi:10.1029/2009jg000968, 2009. M.,Temporal Wabakanghanzi, controls J. ontropical dissolved N., river, organic and Democratic matterdoi:10.1029/2009jg001180, Six, 2010. Republic and J.: of lignin Congo, biogeochemistry J. in Geophys.dissolved a organic Res.-Biogeo., pristine matter 115, propertiesdoi:10.1029/2011jg001928, 2012. G03013, of rivers in the USA, J.Source Geophys. and Res., biolability 117, of ancient G03001, the dissolved Tibetan organic Plateau, Geochim. matter Cosmochim. in Ac.,2014. glacier 142, and 64–74, doi:10.1016/j.gca.2014.08.006, lake ecosystems on dissolved organic matter (CDOM) in Danish278, coastal, doi:10.1006/ecss.2000.0645 waters, 2000. Estuar. Coast. Shelf S., 51, 267– Rapid loss of lakes,doi:10.1073/pnas.1411748112 2015. on the Mongolian Plateau, P. Natl.Seasonal Acad. variation Sci. of USA,photooxidation, CDOM 112, Limnol. and 2281–2286, Oceanogr., 42, DOC 674–686, in 1997. the Middlein Atlantic a Bight: prairie saline terrestrial lake, inputs Limnol. Oceanogr., and 45, 763–774,Evaluation 2000. of specificand ultraviolet absorbance reactivity asdoi:10.1021/es030360x, an of 2003. indicator of dissolved the organic chemical composition carbon, Environ. Sci. Technol., 37, 4702–4708, and photoreactivity of(Southern chromophoric Ocean), Mar. dissolved Chem., 118, organic 129–139,, doi:10.1016/j.marchem.2009.11.008 matter 2010. incharacteristics the Antarctic of Peninsula Proceedings, Hawaii, oceans 10–13 November 1998. around Australia,organic matter Ocean for andi optics artificial coastal XIV lake (Shiwha) conference and the papers, upstream catchments at two 2014. on the specificmatter, spectral and other absorption particulate materials, curves Limnol. of Oceanogr., 26, phytoplankton 671–689,matter 1981. pigments, fluorescence dissolved in organic of marine phytoplankton, Mar. and Chem., estuarine 77, 7–21, environments:, doi:10.1016/s0304-4203(01)00072-x an 2002. investigationduring into flood the and non-flood role Aquat. conditions Sci., 76, in 115–129, a doi:10.1007/s00027-013-0318-3 , river-floodplain 2014. system ofinterdependencies the Danube among (Austria), assumption, global J. Geophys. Res., ocean 110, C07011, doi:10.1029/2004jc002527, color 2005. properties:phycocyanin in potable reassessing water95, sources the 68–80, through, doi:10.1016/j.isprsjprs.2014.06.008 an 2014. bio-optical adaptive model, ISPRS J. Photogramm., Li, Z. C., Shi, K., and Zhao, Y.: Remote estimation of chlorophyll waters: three-band model,doi:10.1016/j.rse.2013.05.017 2013a. vs. GA-PLS model, Remoteand Sens. Liu, L.: Environ., Spatiotemporalhumid/semi-arid characterization 136, region, of China, 342–357, dissolved Hydrol.17-4269-2013, carbon Earth 2013b. for Syst. inland Sci., waters 17, in 4269–4281, semi- doi:10.5194/hess- Rochelle-Newall, E. J. and Fisher, T. R.:Sieczko, A. Production and of Peduzzi, P.: Origin, chromophoric enzymatic response dissolved and organic fate of dissolvedSiegel, organic matter D. A., Maritorena, S., Nelson, N.Song, B., K., and Li, Behrenfeld, L., Tedesco, M. L. J.: P., Independence Li, S., and Hall, B. E., and Du, J.: Remote quantification of Prieur, L. and Sathyendranath, S.: An optical classification of coastal and oceanic waters based Song, K. S., Li, L., Tedesco, L. P., Li, S., Duan, H. T., Liu, D. W., Hall, B. E., Du, J., Song, K. S., Zang, S. Y., Zhao, Y., Li, L., Du, J., Zhang, N. N., Wang, X. D., Shao, T. T., Guan, Y., Spencer, R. G. M., Aiken, G. R., Wickland, K. P., Striegl, R. G., and Hernes, P. J.:Spencer, Seasonal R. and G. M., Stubbins, A., Hernes, P. J., Baker, A., Mopper, K.,Spencer, Aufdenkampe, R. A. G. K., M., Hernes, P. J., Ruf, R., Baker, A., Dyda, R.Spencer, Y., R. Stubbins, G. M., A., Butler, and K. D., Six, and Aiken, J.: G. R.: Dissolved organic carbon andSpencer, R. chromophoric G. M., Guo, W., Raymond, P.A., Dittmar, T., Hood, E., Fellman, J., and Stubbins, A.: Stedmon, C. A., Markager, S., and Kaas, H.: Optical properties and signatures of chromophoric Tao, S., Fang, J., Zhao, X., Zhao, S., Shen,Vodacek, H., Hu, A., H., Blough, Tang, Z., N. Wang, Z., V., and DeGrandpre, Guo,Waiser, M. Q.: J. M. and Robarts, R. D., D.: Changes Peltzer, in compositionWeishaar, and E. reactivity J. of L., T., allochthonous DOM Aiken, and G. R., Nelson, Bergamaschi, R. B. A., K.: Fram, M. S., Fujii, R., and Mopper, K.: Ortega-Retuerta, E., Reche, I., Pulido-Villena, E., Agusti, S., and Duarte,Parslow, C. J. M.: Distribution S., Clementson, L. A.,Phong, D. Turnbull, D., A. Lee, Y., Shin, R., K. and H., and McKenzie, Hur, J.: D. Spatial C.: variability in Bio-optical chromophoric dissolved 5 5 15 25 30 10 20 20 10 15 25 30 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | a 24) = n is chlorophyll a ). Chl ). Turb represents water 1 1 − − 30.275.103.48 10.47–158.24 0.57 0.83–26.21 5.47–20.73 0.79–3.74 68.793.801.87 23.03–300.50 642.159715.26 1.39–19.03 96.00–2906.40 1236–41483.34 000.00 0.12–6.31 608.75 93.10–1505.00 1.75–2521.20 0.09 0.91–1.25 11.06 0–41.07 0.004 0.015–0.031 ± ± ± ± ± ± ± ± ± ± ± ± ± ± . 1 − m 5922 5921 1 − 22) Terminal water ( = n was LmgC 254 9.87 4.71–40.07 36.16 53.60 48.00–298.5670.62 53.40–372.00 652.70 743.59 6.64 8.44–39.74 83.83 1.68 0.60–7.14 5.60 2.301.08 5.43–12.30 1.08–4.79 8.02 1.90 0.004 0.015–0.027 0.02 0.630.04 0.64–3.51141.64 0.06–0.23 106.70–745.0020.80 5729.69 3.95 2.19–83.84 4.58 1.52 0.04–11.06 273.79 0.17 6.27 0.73–1.35 1.05 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ering in trophic state and altitude, Limnol. Oceanogr., 55, 2645–2659, River water ( ff Mean Min–Max Mean Min–Max ). The unit SUVA 7.80 2.74 4.62 1.00 1 0.019 − Water quality and CDOM absorption parameters of water samples collected in Hulun 440 2.68 335 18.29 254 a 250 : 365 275–295 R CDOM CDOM (CDOM) in first-year,doi:10.1016/j.marchem.2014.07.007 sea 2014. ice in the westerndissolved organic Canadian carbon in Arctic, Georgia (USA)Limnol., Mar. rivers: 62, the Chem., 41–46, impact 2003. of 165, molecular size 25–35, distribution, J. Characteristics and sources of chromophoricPlateau, dissolved organic China, matter di in, lakesdoi:10.4319/lo.2010.55.6.2645 of 2010. the Yungui and fluorescencemiddle of and chromophoric,doi:10.1080/02705060.2005.9664760 lower 2005. dissolved reaches organic of matter the inmatter Yangtze (CDOM) shallow absorption River, characteristicsa lakes in J. large relation shallow in Freshwater subtropical to lake,6, fluorescence the Hydrobiologia, Ecol., 2007. in 581, Lake 43–52, 20, Taihu, doi:10.1007/s10750-006-0520- China, 451–459, DOC 25.99 a E SUVA S TNTPTAlkECTDS 1.33 Turb 156.22 0.11 Chl 325.95 a 163.07 20.21 S concentration (µgL TN, TP, TDS, TSM, TAlk and DOCmatter, total represent alkalinity total and nitrogen, dissolved total organic phosphorus, carbon total concentration, dissolved respectively solids, (mg total L suspended turbidity (NTU), and EC represents the electrical conductivity of water samples (µscm Table 1. Buir plateau. Xie, H., Aubry, C., Zhang, Y.,Yacobi, Y. and Z., Alberts, J. Song, J., Takacs, M., G.: and Mcelvaine, Chromophoric M.: Absorption spectroscopy dissolved of colored organicZhang, Y., matter Zhang, E., Yin, Y., van Dijk, M. A.,Zhang, Feng, Y. L., L., Qin, Shi, B. Z., Q., Liu, Zhang, M., L., and Zhu, Qin, G.Zhang, B.: Y. L., W., Qin, B. and Q., Zhu, Chen, G. W., Zhang, W. L., M.: and Yang, L. Spectral Y.: Chromophoric dissolved absorption organic 5 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , b b b 1 − 0.073 275–2295 − S b (440) 0.0680.024 0.015 0.131 0.377 0.083 0.567 0.089 0.264 0.164 0.985 − − − − NAP a concentrations unit is µgL a b b , chl (440) 1 − 0.515 0.377 phy a b a (440) 0.0070.1210.056 0.151 0.026 0.224 0.048 0.178 0.078 0.194 0.062 0.151 5924 5923 0.288 PB − − − − a cients for general water quality and light absorption b b b b ffi (440) 0.083 0.055 0.081 0.050 0.506 0.411 0.548 0.401 0.534 − CDOM a b b b b (335) . 1 0.01. 0.024 − 0.021 0.084 − CDOM p < a b Pearson correlation coe Study area location and sampling station distribution. a 0.05; p < EC DOCpH 0.527 Chl TSM 0.192 0.021 0.129 0.045 0.985 TPTDS 0.508 0.483 TN 0.574 EC unit is µscm a Units of DOC, TN, TP, TDS, TSM, and DOC concentrations are mgL Figure 1. Table 2. properties. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | factors loading (a) represents river waters.  5926 5925 represents terminal waters, and • sample scores. (b) Correlation between DOC and alkalinity, EC, TN, and TP in Hulun Buir plateau water. PCA of the physico-chemical characteristics of all collected waters, data, and Figure 3. Figure 2. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 5928 5927 Relative contributions of CDOM, phytoplankton and non-algal particles to total non- Pareto–Lorenz curves derived from the total non-water light absorption at 440 nm. Figure 5. Figure 4. water light absorption at 440 nm. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 44). = n 5929 RDA of CDOM adsorption data and water quality parameters ( Figure 6.