Characteristics and sources of chromophoric dissolved organic matter in lakes of the Yungui Plateau,China,differing in trophic state and altitude
Yunlin Zhang,a,*,1Enlou Zhang,a Yan Yin,a Mark A.van Dijk,b Longqing Feng,c Zhiqiang Shi,a Mingliang Liu,a and Boqiang Qin a
a Taihu
Lake Laboratory Ecosystem Research Station,State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing,China
b Netherlands Institute of Ecology (NIOO-KNAW),Department of Microbial Ecology,Nieuwersluis,The Netherlands
c College of Resource an
d Environment Science,Nanjing Agricultural University,Nanjing,China
Abstract
The high-mountain lakes on the Yungui Plateau in China are exposed to high-intensity ultraviolet radiation,and contain low concentrations of chromophoric dissolved organic matter (CDOM).We determined CDOM absorption,fluorescence,composition,and source in 38lakes on the Yungui Plateau at altitudes of 1516to 4591m above sea level.Total nitrogen (TN),total phosphorus (TP),and chlorophyll a (Chl a )concentrations significantly increased with increasing trophic state,and decreased with altitude.The CDOM absorption coefficient a CDOM (280)significantly increased with increasing trophic state,but not with altitude.There were significant and negative correlations between altitude and TN,TP,Chl a concentrations,and a CDOM (280).Parallel factor analysis identified two humic-like and two protein-like fluorescent components.Humic-like component 1was terrestrially derived and positively correlated to CDOM https://www.doczj.com/doc/f15600788.html,ponent 2was similar to a marine humic-like substance originating from biological degradation of https://www.doczj.com/doc/f15600788.html,ponents 3and 4were autochthonous tryptophan-like and tyrosine-like fluorophores.CDOM was,thus,a mixture of material from the catchment and autochthonous material produced by biota in the lake.CDOM fluorescence characteristics of oligotrophic and mesotrophic lakes were dominated by the spectral signatures of protein-like components,but marine and terrestrial humic-like components dominated in eutrophic lakes.The fluorescence indices FI 255,FI 310,and FI 370were useful tools for readily defining and classifying CDOM characteristics in the Yungui Plateau lake waters.
Dissolved organic matter (DOM)is mainly composed of humic substances,carbohydrates,and proteinaceous mate-rial,and plays an important role in the global carbon cycle (Benner 2002).Chromophoric dissolved organic matter (CDOM)is the colored fraction of DOM with chemical properties that cause it to absorb energy,and re-emit it as fluorescence.It originates from in situ microbial decompo-sition of plant matter and extracellular release by aquatic organisms (autochthonous [Wang et al.2007;Zhang et al.2009]),as well as from partially degraded organic material from the surrounding terrestrial environment transported by rivers and groundwater (allochthonous;Murphy et al.2008).As an optically active substance,the CDOM concentration can significantly influence the underwater light field (Laurion et al.2000).Furthermore,photo-degradation and microbial degradation of CDOM result in the emission of the greenhouse gases CO 2and CH 4,accelerating global warming (Stedmon et al.2007;Tranvik et al.2009).
Although the ultraviolet-B (UV-B)radiation-penetration inhibiting properties and ecological significance of CDOM have often been reported in plateau and high-mountain lakes (Sommaruga and Psenner 1997;Laurion et al.2000;Sommaruga 2001),little is known about the composition,sources,dynamics,and fate of CDOM in these environ-ments (Mladenov et al.2008).Both the trophic state and altitude of a lake can be expected to have a fundamental effect on dissolved organic carbon (DOC)concentration and composition (Williamson et al.1999;Sobek et al.2007;Webster et al.2008).Eutrophication by increased terrestrial nutrient input will significantly increase the CDOM concentration by increasing algal blooms (Tzortziou et al.2008;Zhang et al.2009).Altitude affects CDOM in three ways:(1)high altitude inhibits human activity and,thus,decreases anthropogenic CDOM input;(2)UV-B radiation increases with altitude,which leads to higher increases in the photochemical degradation rate of CDOM,which further lowers the equilibrium CDOM concentration and alters CDOM composition;(3)the natural export of CDOM from terrestrial to aquatic ecosystems will decrease as terrestrial productivity and the size of the catchment area decreases with increasing altitude (Jansson et al.2008).CDOM is a complex mixture of organic materials and,therefore,it is very difficult to identify every constituent.However,optical techniques including spectrophotometry and three-dimensional excitation-emission spectra (EEMs)fluorometry have provided useful information about the DOM composition,sources,and molecular size (Kowalc-zuk et al.2005;Liu et al.2007;Wang et al.2007).EEMs is considered the simplest and most effective technique for studying the composition and source of CDOM,due to its simplicity and sensitivity.However,there has been a limitation because the EEMs of CDOM from natural waters are composed of overlapping signals of various types of fluorophores,making it very difficult to assess the
*Corresponding author:ylzhang@https://www.doczj.com/doc/f15600788.html,;yunlinzhang@https://www.doczj.com/doc/f15600788.html,
1Present address:Nanjing Institute of Geography and Limnol-ogy,Chinese Academy of Sciences,Nanjing,P.R.China
Limnol.Oceanogr.,55(6),2010,2645–2659
E
2010,by the American Society of Limnology and Oceanography,Inc.doi:10.4319/lo.2010.55.6.2645
2645
dynamics of CDOM based solely on the apparent EEMs. To address this,Stedmon et al.(2003)applied a statistical modeling approach called Parallel Factor Analysis(PAR-AFAC)to decompose EEMs into individual fluorescent components.This approach provides a considerable advantage over traditional methods in interpreting the multidimensional nature of EEMs data sets.
In the present study,we determined the absorption, fluorescence,and source characteristics of CDOM in38 lakes on the Yungui Plateau of southwest China,which differed in their trophic state and altitude.The main objectives of this study were to:(1)determine CDOM absorption coefficients along gradients of trophic state and altitude;(2)characterize CDOM components from EEMs, and determine their potential sources,using the PAR-AFAC model and fluorescence index;and(3)determine the correlations between CDOM fluorescence and the absorp-tion coefficient,and other water-quality parameters.Methods
Study lakes—Thirty-eight lakes on the Yungui Plateau in southwest China,with elevations from1516m to4591m above sea level,and of various trophic states,were sampled in October2006and2007(Table1).The study included all lakes larger than1km2,with the exception of Lake Dianchi,which was excluded due to high,wind-induced waves.The lakes were classified into three trophic-state classes:oligotrophic(n519),mesotrophic(n514),and eutrophic(n55).The trophic state was assessed according to four water-quality indices:Secchi disk depth(SDD); total nitrogen(TN);total phosphorus(TP);and chloro-phyll a(Chl a),using the Trophic State Index(TSI;Jing et al.2008).
To analyze regional variations,we arranged the data according to three trophic states(oligotrophic,mesotro-phic,and eutrophic),and three altitude categories
Table1.Location,area,and trophic state of the38lakes on the Yungui Plateau,China.The trophic states are:E5eutrophic,M5 mesotrophic,O5oligotrophic.nd5no data.
Lake Latitude
(N)
Longitude
(E)
Altitude
(m)
Area
(km2)
Trophic
state
No.of samples
20062007
Bigutianchi27.62399.64238090.21M11 Bitahai27.82899.9443568 1.4M11 Chenhai26.45–26.633100.633–100.683155077.2M03 Cheou29.262100.0354446,1M11 Cibihu26.16699.94120338.5O10 Cuoniba30.30299.5524400,1O10 Cuonibapang30.32099.5614483,1O11 Dahaikou27.324102.4563192,1E10 Daxueshantianchi28.59199.8654506,1O11 Erhai25.600–25.967100.010–100.3001954249M08 Fuxianhu24.350–24.633102.817–102.951720211O18 Hegou27.355100.0704121,1O01 Lashihai26.872100.143243514.4M01 Lietahu29.092101.5724291,1M11 Litanghu29.474100.2074591 1.5O10 Longchang29.410100.2784292,1M01 Luguhu27.683–2.75100.75–100.833269148.5O03 Poshankou25.589103.1132173,1M10 Pugelian27.324102.4553237,1M01 Qiaohai27.783–27.867102.267–102.35151631.0M10 Qiluhu24.133–24.217102.717–102.817180136.9E11 Qingdagou30.215101.0662906,1O01 Qingshuihai25.594103.11221827.2O11 Shadecuo29.745101.3584423,1O11 Shadehe129.681101.4083255,1O01 Shadehe229.714101.4003639,1O01 Shadehe329.727101.3883821,1O01 Shuduhu27.91399.9523611 1.1E11 Tagonghu130.300101.2944323,1O10 Tagonghu230.302101.3034299,1O10 Wuxuhai29.491101.4023625,1O11 Xinyicuo129.393100.1044392,1O11 Xinyicuo229.395100.0944389,1O11 Xinyunhu24.283–24.383102.750–102.800173234.7E13 Yangzonghai24.850–24.967102.967–103.017177531.7O13 Yihai28.733102.2352274,1M11 Yuejinshuiku nd nd2496,1E10 Zheduoshanyakou30.078101.7964194,1O10 2646Zhang et al.
(#2000m,2000–4000m,and $4000m).We also qualitatively assessed the effect of trophic state on CDOM concentration and composition using the correlations between the value of TSI and CDOM absorption,and the fluorescent component intensity.
Sample collection—To determine CDOM absorption,fluorescence,Chl a ,and nutrient concentrations,water from 0-m to 1.0-m depth was collected in 4-liter acid-cleaned plastic bottles,and held on ice in the field.Single samples were collected from the center in most lakes between 07and 30September 2006,and between 25September and 30October 2007;in addition,several evenly distributed samples were collected in some lakes between 25September and 30October 2007(Table 1).The SDD was measured in situ with a 30-cm-diameter black and white quadrant https://www.doczj.com/doc/f15600788.html,titude,longitude,and altitude,were recorded in situ using a Global Positioning System.Absorption measurement—All samples were filtered at low pressure,first through a precombusted Whatman GF/F filter (0.7m m),and then through a prerinsed 25-mm Millipore membrane cellulose filter (0.22m m)into glass bottles precombusted at 550u C for 6h.
The absorption spectra of CDOM were obtained between 240nm and 800nm,at 1-nm intervals,using a Shimadzu UV-2401PC UV-Vis recording spectrophotom-eter with matching 4-cm quartz https://www.doczj.com/doc/f15600788.html,li-Q water was used as reference.Absorbance spectra (l )were baseline-corrected,by subtracting the mean absorbance for the spectral range from 650nm to 700nm.Absorption coefficients were obtained by using the following equation:
a CDOM l eT~2:303OD l eT=r
e1T
where a CDOM (l )is the CDOM absorption coefficient,OD(l )is the corrected optical density,and r is the cuvette path length in m.In this study,the concentration of CDOM is expressed using a CDOM (280).
The spectral slope of the CDOM absorption curve,(S ),is calculated by nonlinear regression over the 280–500-nm wavelength range,according to the equation of Stedmon et al.(2000):
a CDOM l eT~a CDOM l 0eTexp S l 0{l eT? z K
e2T
where a CDOM (l )is the absorption coefficient,a CDOM (l 0)is the absorption coefficient at reference wavelength l 0,which is generally chosen to be 440nm,and S is the spectral slope as a measure of absorption decrease with increasing wavelength.K is a background parameter accounting for baseline shifts or attenuation due to factors other than CDOM.
A diversity of linear,nonlinear,and hyperbolic fittings across different spectral ranges have previously been used to obtain values for the spectral slope S ,making inter-laboratory comparisons very difficult (Twardowski et al.2004;Zhang et al.2007).To eliminate such variability,Helms et al.(2008),by comparing CDOM from water from wetlands to photo-bleached oceanic water,advocated that the spectral slope ratio (S R )of two narrow wavelength ranges (275–295nm and 350–400nm)can be used to
indicate the molecular weight,source,and the degree of photo-bleaching of CDOM.We adopted this approach,and calculated S by applying nonlinear regression using Eq.2from 280nm to 500nm,275nm to 295nm,and 350nm to 400nm,then S R was defined as S 275–295:S 350–400.Three-dimensional fluorescence measurement—EEMs of CDOM were measured using a Hitachi F-7000fluorescence spectrometer (Hitachi High-Technologies)with a 700-voltage xenon lamp.The scanning ranges we used were 200–450nm for excitation,and 250–600nm for emission.Readings were collected in ratio mode at 5-nm intervals for excitation,and at 1-nm intervals for emission,using a scanning speed of 2400nm min 21.The band-passes were 5nm for both excitation and emission.A Milli-Q water blank of the EEMs was subtracted to eliminate the water Raman scatter peaks.
In order to be able to make comparisons with other studies using different fluorometers,a correction of the spectra for instrumental response was conducted according to the procedure recommended by Hitachi (Hitachi F-7000Instruction Manual;Cory et al.2010),which comprised both excitation and emission calibration.First,excitation was calibrated by using Rhodamine B as standard (quantum counter),and a single-side frosted red filter in excitation scan mode.Then,emission was calibrated with a diffuser in synchronous scan mode.The excitation and emission spectra obtained over the range 200–600nm were applied internally by the instrument (through fluorescence solutions 2.1software)to correct the subsequent spectra.In order to eliminate the inner-filter effect,the EEMs were corrected for absorbance by multiplying each value in the EEMs with a correction factor,based on the premise that the average path length of absorption of the excitation and emission light is one-half the cuvette length (McKnight et al.2001).
Fluorescence intensity was calibrated in quinine sulfate units (QSU),where 1QSU is the maximum fluorescence intensity of 0.01mg L 21of quinine (qs)in 1mol L 21H 2SO 4at the excitation wavelength of 350nm and emission wavelength of 450nm (Hoge et al.1993;Wada et al.2007).Rayleigh scatter effects were removed from the data set by excluding any emission measurements made at wavelengths #excitation wavelength +5nm,and at wavelengths $excitation wavelength +300nm.Values in the two triangle regions (emission wavelength #excitation wavelength +5nm,and $excitation wavelength +300nm)were substituted by zeroes in the EEMs.The contour figures of the EEMs were drawn using Origin 6.0.
Calculation of fluorescence index—To characterize CDOM in the Yungui Plateau lakes,we used three different indices;FI 255,FI 310(Zsolnay et al.1999;Huguet et al.2009),and FI 370(McKnight et al.2001).Each of these is now briefly described.
The humification index (FI 254)introduced by Zsolnay et al.(1999),was based on location of emission spectra,and initially used to estimate the degree of maturation of DOM in soil;subsequently,it was used by Huguet et al.(2009)to define and classify DOM characteristics in estuarine waters.
CDOM in lakes of the Yungui Plateau
2647
FI254is defined as the ratio between the average fluores-cence intensity from300nm to345nm,divided by the average from435nm to480nm,both excited at254nm(in the present study,255nm was used—hence,FI255).When the degree of aromaticity of DOM increases,the emission spectrum excited at254nm becomes red-shifted;thus,FI254 increases.High FI254values correspond to a maximal fluorescence intensity at long wavelengths and,thus,to the presence of complex molecules such as high-molecular-weight aromatics(Senesi et al.1991).
The index of recent autochthonous contribution,indi-cating the presence of the autochthonous biological activity (FI310)was introduced by Huguet et al.(2009),and was determined as the ratio of fluorescence intensity at380nm, divided by that at430nm,both excited at310nm.High values of FI310(.1)corresponded to a predominantly autochthonous origin of DOM and to the presence of organic matter freshly released into water,whereas a low value of FI310(0.6–0.7)indicates lower autochthonous DOM production in natural waters.
To distinguish sources of isolated aquatic fulvic acids, McKnight et al.(2001)presented a fluorescence index(FI370) from the ratio of fluorescence intensity at an emission wavelength of450nm divided by fluorescence intensity at an emission wavelength of500nm,both excited at370nm.This index has a value of,1.9for microbially derived fulvic acids,and,1.4for terrestrially derived fulvic acids.
The PARAFAC modeling—PARAFAC statistically de-composes the EEMs of the complex mixture of DOM fluorophores to determine the components,without any assumptions about the shape of their spectra,or concen-tration,or number.The data signal is decomposed into a set of three linear terms and a residual array(Stedmon et al. 2003).The number of fluorescent components found using PARAFAC ranges from4to13for diverse marine and freshwater environment(Cory and McKnight2005;Yama-shita et al.2008;Kowalczuk et al.2009).
Stedmon and Bro(2008)described how to characterize DOM fluorescence with PARAFAC,including a split-half analysis used to validate the identified fluorescent compo-nents.Split-half analysis involves dividing the data set into two random,typically equal-sized groups,and then making a PARAFAC model of both halves independently.If the correct number of components is chosen,the loadings from both models should be the same,due to the uniqueness of the PARAFAC model.
The PARAFAC analysis in our study was carried out in matrix laboratory(MATLAB)with the dissolved organic matter fluorescence(DOMFluor)toolbox for MATLAB, according to Stedmon and Bro(2008).For PARAFAC modeling,excitation wavelengths from200nm to220nm, and emission wavelengths from250nm to300nm,were deleted from each EEMs because of the unreliable data in these regions.Two samples were removed after inter-comparison of the data set to determine whether samples contained measurement errors.
Other water-quality parameters—TN and TP were analyzed by the molybdenum blue method using a Shimadzu UV2401UV-Vis spectrophotometer.Water samples were first filtered through Whatman GF/F filters (0.7m m)to analyze total dissolved nitrogen(TDN),and total dissolved phosphorus(TDP).The filtered water samples were then digested by alkaline potassium persul-phate in a high-pressure sterilization vessel at120u C,prior to determination of TDN and TDP concentrations with the spectrophotometer(Zhu et al.2008).The TDN and TDP concentrations were measured only for the2007samples.
Samples(250mL–2liters)for Chl a were collected on Whatman GF/F filters.The Chl a was extracted with ethanol(90%)at80u C and analyzed spectrophotometrical-ly at750,663,645,and630nm(SCOR-UNESCO1966).
Statistical analyses—Statistical analyses(mean value, linear,nonlinear fitting,and multiple regression)were performed with Statistical Program for Social Sciences (SPSS)11.0software.Differences in parameters between the three different trophic states(oligotrophic,mesotro-phic,and eutrophic states),and the three different altitudes (#2000m,2000–4000m,and$4000m),were assessed with an independent samples t-test using a p-value of0.05 to determine significance.Regression and correlation analyses were used to examine the relationships between variables(CDOM absorption,fluorescence,water-quality parameters,and altitude)using a p-value of0.05. Results
General characteristics—The38lakes comprised19 oligotrophic,14mesotrophic,and5eutrophic lakes.The percentage of lakes that were oligotrophic increased with increasing altitude,accounting for28.6%,47.1%,and 78.6%at the three altitude categories of#2000m,2000–4000m,and$4000m,respectively.There was no eutrophic lake at an altitude higher than4000m,due to the natural changes in catchment properties and low human activities with increased altitude.
From oligotrophic to mesotrophic,and further to eutrophic lakes,the TN,TP,and Chl a concentrations increased significantly:for TN from0.2360.11(mean value6SD)to0.5660.29,and further to 1.776 0.69mg L21;for TP from0.01260.006to0.02760.014, and further to0.11860.076mg L21;and for Chl a from 1.046 1.07to 5.696 4.32,and further to37.56 26.7m g L21(t-test,p,0.001;Table2).With increasing altitude from#2000m to2000–4000m,and further to$ 4000m,TN,TP,and Chl a concentrations significantly decreased(t-test,p#0.05;Table2).Significant and negative correlations were found between altitude and TN,TP,Chl a concentrations,and TSI(Fig.1).However, altitude explained,39%of the variability in TN,TP,and Chl a concentrations,indicating that other variables also affected the variability in TN,TP,and Chl a concentra-tions.
Optical properties of CDOM—Among the38lakes, a CDOM(280)ranged from0.73m21to22.07m21,with a mean of6.6365.33m21.The lowest a CDOM(280)was recorded in the oligotrophic lake Daxueshantianchi,lying
2648Zhang et al.
at4506m above sea level,and the highest a CDOM(280)was recorded in the eutrophic lake Qiluhu at1767m.With increasing trophic state,CDOM absorption increased significantly(t-test,p,0.001),with the mean a CDOM(280) ranging from3.0361.60m21to7.7462.91m21and further to16.5864.86m21for oligotrophic,mesotrophic, and eutrophic lakes,respectively(Table2).A significant and positive linear relationship was found between TSI and a CDOM(280)(r250.46,p,0.001).
When all three trophic states were considered together,
a CDOM(280)decreased from8.1266.34m21to6.666
4.93m21,and further to4.3262.98m21,in the three altitude categories of#2000m,2000–4000m,and$ 4000m;but this decrease was not statistically significant. However,a significant negative linear relationship was found between log-transformed a CDOM(280)and log-transformed altitude(r250.07,p,0.05).The multiple linear regression analysis showed that a higher determina-tion coefficient was recorded(r250.51,p,0.001)when TSI and altitude were used as variable inputs than when any single variable was used.
The mean spectral slope S280–500based on all data was 18.8869.41m m21.From the oligotrophic to mesotrophic state,S280–500increased significantly(t-test,t523.824,df 565,p,0.001),and S R decreased significantly(t-test,t5 4.519,df565,p,0.001).From the mesotrophic to eutrophic state,there was almost no change in S280–500,and no statistically significant change in S R.There was a significant positive linear relationship between TSI and S280–500(r250.29,p,0.001),and a significant negative linear relationship between TSI and S R(r250.09,p, 0.01).With increasing altitude from#2000m to2000–4000m,S280–500and S R decreased significantly(t-test,t5 23.548,df555,p50.001and t-test,t52.381,df555,p 50.021),but from2000–4000m to$4000m,S280–500and S R did not change significantly(Table2).The significant and negative linear relationships were found between log-transformed altitude and S280–500(r250.12,p,
0.005),
Table2.Mean values of water-quality parameters and CDOM absorption grouped as:all sites(all),all oligotrophic sties(O),all mesotrophic sites(M),all eutrophic sites(E),all sites with altitude,2km(#2km),all sites with altitude between2km and4km(2–4km),and all sites with altitude.4km($4km).
Item TN(mg L21)TP(mg L21)Chl a(m g L21)a CDOM(280;m21)S280–500(m m21)S R n*
All0.5960.620.03360.0477.85615.81 6.6365.3318.8969.41 3.1361.8378(38)
O0.2360.110.01260.006 1.0461.07 3.0361.6014.64610.65 4.1861.6939(19)
M0.5660.290.02760.014 5.6964.327.7462.9123.1866.02 2.3561.5228(14)
E 1.7760.690.11860.07637.5626.716.5864.8623.0463.46 1.5960.3011(5)
#2km0.8860.760.05160.06414.48621.858.1266.3423.5169.58 3.6862.0332(7)
2–4km0.4560.390.02460.021 5.3268.66 6.6664.9315.1367.80 2.5761.2725(17) $4km0.2060.060.01260.0050.7460.89 4.3262.9816.3168.17 2.9861.9221(14)
*First value in the column n is the number of samples,second value in brackets is the number of lakes.
CDOM in lakes of the Yungui Plateau2649
and between log-transformed altitude and S R (r 250.07,p ,0.05).
EEMs characterization of CDOM—For all 76samples,four marked fluorescence peaks were recorded,based on the EEMs ‘peak picking’technique;the peaks comprised two humic-like fluorescence peaks and two protein-like fluorescence peaks (Coble 1996).An example of measured EEMs for each trophic state is shown in Fig.2.The first humic-like fluorescence peak was in the ultraviolet range (Ex max ,250nm,Em max 5400–430nm),and the second was in the visible range (Ex max 5300–340nm,Em max 5400–450nm).The first protein-like fluorescence peak was at shorter excitation wavelengths (Ex max 5220–240nm,Em max 5340–350nm),due to tryptophan fluorescence,and the second protein-like peak,at a longer excitation wavelength (Ex max 5260–280nm,Em max 5330–350nm)was also due to tryptophan fluorescence.
The fluorescence properties of CDOM differed substan-tially with trophic state.In an oligotrophic lake,such as Lake Daxueshantianchi,the protein-like fluorescence peaks were markedly higher than the humic-like fluorescence peaks.In contrast,in a eutrophic lake,such as Lake Qiluhu,the humic-like fluorescence peaks were markedly higher than the protein-like fluorescence peaks.
Four fluorescent components were identified by PAR-AFAC,based on the split-half validation procedure (Fig.3).The largely overlapping excitation and emission loadings of the four components,modeled on the halves of the data set,and on the whole data set,are shown in Fig.3.All fluorescent components had single emission maxima,and single or multiple excitation maxima.The excitation and emission characteristics of these CDOM fluorescent components we identified are given in Table 3,together with examples of matching components identified by other researchers who have modeled CDOM EEMs in aquatic environments using the PARAFAC model.
The four components we identified from the fluorescence spectra were a terrestrial humic-like component (C1),a biological degradation humic component (C2;named as marine humic-like component in marine environment),and protein-like components (C3and C4;Table 3).Component 1displayed two excitation maxima (at 255nm and 350nm)corresponding to a single emission maximum (at 471nm),similar to the humic-like fluorophores defined by Coble (1996)and Coble et al.(1998),with excitation maxima in the ultraviolet region (peak A)and the visible region (peak C).Component 2had similar excitation and emission maxima as the M peak and N peak observed in the ocean and in phytoplankton degradation experiments (Coble 1996;Coble et al.1998;Zhang et al.2009).Peak fluorescence in this region is considered to be coupled to phytoplankton productivity,because it is most often observed in the open ocean environment,and has also been found to be produced and altered by microbial reprocessing during a mesocosm experiment with CDOM produced by plankton (Stedmon and Markager 2005a ).Components 3and 4had excitation and emission characteristics similar to an autochthonous protein-like compound (Coble et al.1998;Yamashita et al.2008;Kowalczuk et al.2009).Component 3had excitation and emission characteristics similar to tyrosine,and component 4had excitation and emission characteristics similar to tryptophan.These two components represent DOM that contains autochthonous CDOM.
The mean fluorescence intensity of the four components,and their respective contribution to total CDOM fluores-cence intensity (the percentage of fluorescence maximum score for each component to the total fluorescence maximum scores of all components),as derived by the PARAFAC model,differed per trophic state and altitude (Fig.4).For oligotrophic lakes,the fluorescence intensities of the autochthonous fluorophores (C3and C4)were especially high (43.3%and 34.6%,respectively),and those of the allochthonous fluorophores (C1)were especially low (5.2%).In contrast,for eutrophic lakes,the contribution of allochthonous fluorophores (C1)was substantially higher,from 5.2%to 15.3%.
With the increase of trophic state,when all altitudes were considered together,the total fluorescence intensity
signif-
Fig.2.Examples of EEMs for one water sample from each trophic state ([A]oligotrophic;[B]mesotrophic;[C]eutrophic).Fluorescence is in QSU units.
2650Zhang et al.
icantly increased from 8.4963.93to 10.6363.52,and to 13.9462.95QSU (t -test,p ,0.05).Correspondingly,the fluorescence intensities and the contributions of C1and C2significantly increased (t -test,p ,0.01),and the contribu-tions of C3and C4decreased,but not significantly.From the oligotrophic state to mesotrophic,and further to eutrophic,the contributions of C1and C2significantly increased from 5.2%and 16.9%,to 9.9%and 24.2%,and further to 15.3%and 42.0%(t -test,p ,0.01).In parallel,the contributions of C3and C4decreased from 43.3%and 34.6%,to 38.6%and 27.3%,and further to 30.6%and 12.2%,but these decreases were not significantly different.There were significant and positive linear relationships between TSI and C1intensity (r 250.31,p ,0.001),and between TSI and C2intensity (r 250.58,p ,0.001),but no linear relationships between TSI and C3intensity,or between TSI and C4intensity.
We demonstrated trends for changes in intensity and contribution of all four fluorescent components with increase of altitude,regardless of trophic state.With increasing altitude from #2000m to 2000–4000m and further to $4000m,the total fluorescence intensity and the respective intensities of C1,C3,and C4firstly increased and then decreased,but not significantly.With increasing altitude from #2000m to 2000–4000m and further to $4000m,the intensity of C2first slightly (but not significantly)decreased ,then significantly decreased (t -test,t 52.352df 543,p 50.023).Of the four components,only the contribution of C2significantly decreased from #2000m to 2000–4000m (t -test,t 52.333,df 554,p 50.023);there was no statistically significant difference for any of the other three components and altitude.Significant and negative linear relationships were present between log-
transformed altitude and the intensity (r 250.10,p ,0.01),and contribution (r 250.10,p ,0.01)of C2.
The multiple linear regression analysis showed that a higher determination coefficient was recorded when TSI and altitude were used as variable inputs for C1(r 250.46,p ,0.001)and C2(r 250.61,p ,0.001)than when TSI was used as variable input for C1(r 250.31,p ,0.001)and C2(r 250.58,p ,0.001),and when altitude was as variable input for C1(r 250.00,p .0.05)and C2(r 250.10,p ,0.01).However,there was still no significant linear relationship for C3and C4.
Fluorescence index—The variations in the three fluores-cence indices,according to different trophic states and altitude,are shown in Fig.5.The FI 255ranged from 0.23to 6.00,with a mean of 1.5761.14,and a coefficient of variation (CV)of 72.3%for all samples.From the oligotrophic state to mesotrophic,and further to eutrophic,the mean value of FI 255significantly increased from 0.9960.62to 1.7761.02and further to 3.0461.35(t -test,p ,0.005).A significant and positive linear relationship was found between TSI and FI 255(r 250.20,p ,0.001).In contrast,from the altitudes of #2000m to 2000–4000m,and to $4000m,the mean values of FI 255did not vary significantly (1.6360.88,1.6661.50,1.3760.99),and there was no significant linear relationship between altitude and FI 255.
The FI 310ranged from 0.60to 1.54,with a mean of 0.9360.18(CV 519.6%)for all samples.From the oligotrophic to mesotrophic state,the mean value of FI 310significantly decreased,from 1.0060.19to 0.8360.15(t -test,t 53.865,df 565,p ,0.001).However,no significant differences were found for FI 310between the
mesotrophic
Fig.3.The PARAFAC model output showing fluorescence signatures of the four fluorescent components.(A–D)The contour plots present spectral shapes of excitation and emission.(E–H)The line plots present split-half validation results;excitation (left)and emission (right)spectra were estimated from two independent halves of the data set (red and green lines),and the complete data set (black lines).A perfect validation is obtained if loadings from the two halves are identical.
CDOM in lakes of the Yungui Plateau 2651
and eutrophic state,or between the oligotrophic and eutrophic state.No significant linear relationship was found between TSI and FI310.With increasing altitude from#2000m to2000–4000m,and further to$4000m, FI310first significantly decreased(t-test,t54.693,df555, p,0.001),then slightly(but not significantly)increased.A significant and negative linear relationship was found between log-transformed altitude and FI310(r250.21,p ,0.001).
The FI370ranged from1.14to1.80,with a mean of1.37 60.12(CV58.6%)for all samples,suggesting that CDOM was a mixture of allochthonous humic material from the surrounding environment,and autochthonous material produced by biota in the lake.From the oligotrophic to mesotrophic state,the mean value of FI370 significantly decreased from1.4060.13to1.3260.10(t-test,t52.764,df565,p50.007).However,no significant differences were found for FI370between the mesotrophic and eutrophic state,or between the oligotrophic and eutrophic state.No significant linear relationship was found between TSI and FI370.With the increase of altitude from#2000m to2000–4000m,and further to$4000m, FI370firstly significantly decreased(t-test,t52.349,df5 55,p50.023),then slightly and not significantly decreased.
A significant and negative linear relationship was found between log-transformed altitude and FI370(r250.10,p, 0.01).
Correlations between CDOM fluorescence and absorption coefficient,and other water-quality parameters—The deter-mination coefficients and the significance level of the linear relationships between CDOM absorption,the four fluo-rescent components,and five water-quality parameters are shown in Table4.The significant and positive linear correlations between TN and TDN,TP,and TDP (Table4),and the high percentage of TDN in TN(61.0 619.8%)and of TDP in TP(48.2625.7%),showed that dissolved nutrients were an important part of the total nutrient budget.The higher determination coefficients (positive linear relationships)between TN,TDN,and Chl a than between TP,TDP,and Chl a(Table4),suggested that the phytoplankton biomass was mainly controlled by the nitrogen concentration,and that nitrogen was the probable limiting factor of phytoplankton growth in the Yungui Plateau lakes.
The significant and positive linear correlations between CDOM absorption a CDOM(280)and TN,TDN,TP,and TDP showed a close relationship between CDOM and nutrients.The significant and positive correlation between CDOM absorption and Chl a in the Yungui Plateau lakes
Table3.Spectral characteristics of excitation(Ex max)and emission(Em max)maxima of the four fluorescent components identified by Parallel Factor Analysis(PARAFAC)modeling for the whole EEM data set,compared with previously identified sources.
Component
No.Ex max(nm)*Em max(nm)
Coble(1996),
Coble et al.(1998)*
Comparison with other
studies using PARAFAC*
Description and
probable source
C1255(350)471A peak:Ex max5230–260and
Em max5380–460C3:Ex max5270(360)and
Em max5478{
Terrestrial humic-like
substances
C peak:Ex max5320–360and
Em max5420–480C4:Ex max5250(360)and Em max5440{
C2235(290)397M peak:Ex max5290–310and
Em max5370–420C3:Ex max5295and
Em max53981
Marine humic-like
substances
(phytoplankton
degradation)
N peak:Ex max5280and Em max5370C2:Ex max5315and
Em max5418I
C6:Ex max5325(,260)and Em max5385"
C3#225(275)322B peak:Ex max5225–230(275)
and Em max5305–310C4:Ex max5275and
Em max53061
Autochthonous
tyrosine-like
fluorescence C8:Ex max5275and
Em max5304{
C1:Ex max5275and
Em max,300I
C7:Ex max5270and
Em max5299"
C4#225(285)344T peak:Ex max5225–230(275)
and Em max5340–350C6:Ex max5280and
Em max53381
Autochthonous
tryptophan-like
fluorescence
C7:Ex max5280and
Em max5344{
C6:Ex max5250(290)and
Em max5356#
*Secondary excitation band is given in brackets.
{Stedmon et al.(2003).
{Stedmon and Markager(2005b).
1Stedmon and Markager(2005a).
I Murphy et al.(2008).
"Yamashita et al.(2008).
#Kowalczuk et al.(2009).
2652Zhang et al.
indicated that phytoplankton accumulation and decompo-sition were a contributing source of CDOM.
The a CDOM (280)was strongly and positively correlated with the fluorescence of the two humic-like peaks,but only weakly and negatively correlated,or not correlated,with the fluorescence of the two protein-like peaks (Table 4;Fig.6).This result was consistent with prior studies that showed a stronger correlation between CDOM absorption and the humic-like peak than between CDOM absorption and the protein-like peak (Baker and Spencer 2004;Kowalczuk et al.2005).
Table 4shows that components 1and 2,and compo-nents 3and 4,were strongly and positively linearly correlated,suggesting that each pair (humic-like and protein-like fluorescence)had a common source or the same variation.The absence of significant correlation between components 1,2and components 3,4showed that the humic-like and protein-like fluorescence originated from different sources.
Discussion
The effect of trophic state and altitude on lake CDOM—Compared with previous results,CDOM absorption in lakes of the Yungui Plateau are markedly lower than those in lakes in the middle and lower reaches of the Yangtze River (Zhang et al.2005).We have shown that both trophic state and altitude significantly affected CDOM absorption in the Yungui Plateau lakes.With the increase of trophic state,CDOM increased significantly,and this would be expected to decrease the attenuation depth of UV radiation (UVR [Morris and Hargreaves 1997;Laurion et al.2000]).Several mechanisms can explain this significant effect of trophic state on CDOM absorption.The increase of CDOM absorption with trophic state may be partly due to increased anthropogenic and terrestrial input caused by human activity in the catchment area,and partly due to climate change,especially for the low-altitude lakes.In a large database of DOC concentrations and other
param-
https://www.doczj.com/doc/f15600788.html,position of CDOM fluorescence intensity (QSU)of (A,B)four components and (C,D)their respective percent contribution (%)to total CDOM fluorescence intensity derived by the PARAFAC model,differing by trophic state (O 5oligotrophic,M 5mesotrophic,and E 5eutrophic)and
altitude.
Fig.5.Variations in fluorescence indices FI 255,FI 310,and FI 370,according to (A)trophic state (O 5oligotrophic,M 5mesotrophic,and E 5eutrophic)and (B)altitude.The left scale is for FI 255and the right scale is for FI 310and FI 370.
CDOM in lakes of the Yungui Plateau 2653
eters (for 7514lakes on six continents),Sobek et al.(2007)found that the catchment,the soil,and the climate significantly affected DOC concentrations.Furthermore,the input of nutrients accelerated the growth of phyto-plankton,which would increase CDOM absorption,accompanied by CDOM release from phytoplankton degradation (Zhang et al.2009).Additionally,the increase of CDOM may cause the increase of nutrients through photo-degradation and microbial degradation (Stedmon et al.2007;Piccini et al.2009;Tranvik et al.2009).Considering the interactions between CDOM and trophic state,some researchers have proposed to define lake trophic status using the nutrient-color paradigm,which represents CDOM absorption (Williamson et al.1999;Webster et al.2008).
The significant increase of humic-like components (C1and C2)with the increase of trophic state,and the significant positive linear relationships between TSI and C1and C2,showed that trophic state mainly affected the two fluorescence substances.The increase of trophic state,due to the input of terrestrial nutrients from the catchment,would increase the terrestrial humic-like component (C1).The increase of trophic state attributed to the increase of phytoplankton biomass,would increase the production of humic component (C2)during biological degradation processes.Our previous phytoplankton degradation exper-iment,and other similar observations,also demonstrated the rapid increase of this fluorescent substance (Miller et al.2009;Zhang et al.2009).
For the lakes of the Yungui Plateau,there was a significant negative linear relationship between log-trans-formed altitude and log-transformed a CDOM (280),suggest-ing that altitude significantly affected CDOM absorption;however,there were no significant differences between CDOM absorption a CDOM (280)at the three different altitudes when raw data were analyzed.Sobek et al.(2007)also found a significant negative correlation between altitude and DOC concentrations based on a large database of 7514lakes from six continents.As mentioned in the introduction,altitude affects CDOM through decreasing human activity,increasing photochemical degradation,and decreasing terrestrial CDOM input due to the decreases of terrestrial productivity and reducing the catchment area for high-altitude lakes.For example,Morris and Hargreaves (1997)found that a CDOM (320)and the specific absorption a *CDOM (320;the ratio of CDOM absorption to DOC concentration),decreased by 35–52%and 31–48%,respec-tively,during 7d of exposure to incident solar radiation in an experiment on three lakes on the Pocono Plateau.Also in the present study,altitude was also a master variable that incorporated climatic,topographic,and edaphic effects on CDOM,as Sobek et al.(2007)pointed out.
Our multiple linear analysis showed that higher deter-mination coefficients were recorded for CDOM absorption,
Table 4.Determination coefficients and significance levels of the linear relationships between chromophoric dissolved organic matter (CDOM)absorption,fluorescent components,and water-quality parameters.TN:total nitrogen;TDN:total dissolved nitrogen;TP:total phosphorus;TDP:total dissolved phosphorus;Chl a :chlorophyll a ;a CDOM (280):CDOM absorption coefficient at 280nm;C1–C4:Components 1–4.
TN
TDN TP TDP Chl a a CDOM (280)C1C2C3C4TN 1.00—————————TDN 0.90* 1.00————————TP 0.48*0.61* 1.00———————TDP 0.31*0.41*0.88* 1.00——————Chl a
0.86*0.84*0.34*0.16** 1.00—————a CDOM (280)0.66*0.68*0.48*0.31*0.53* 1.00————C10.43*0.31*0.32*0.18**0.38*0.80* 1.00———C20.76*0.76*0.64*0.51*0.64*0.86*0.72* 1.00——C30.000.000.030.000.010.010.030.02 1.00—C4
0.02
0.01
0.01
0.02
0.01
0.08***
0.05
0.02
0.16**
1.00
*p #0.001;**p #0.005;***p #
0.05.
Fig.6.Correlations between the fluorescence intensities of components 1(open squares)and 2(closed circles),and the CDOM absorption coefficients a CDOM (280).
2654Zhang et al.
and for the C1and C2components of fluorescence intensity,when TSI and altitude were used together as variable input,than when any single variable was used. This indicated that trophic state and altitude were likely to be linked each other,and affected CDOM concentration and composition altogether.However,we also noted a marked increase of the determination coefficient when TSI was added,but only a slight increase of the determination coefficient when altitude was added in the multiple linear analysis,which indicated a more important effect of trophic state on CDOM concentration and composition compared to altitude.Of course,altitude might also affect CDOM concentration and composition through the indirect effect of altitude on trophic state,due to the effects of altitude on nutrient input and on human activity,particularly land use. As our results showed,there was a significant negative linear relationship between TSI and altitude.
CDOM fluorescence as a tracer for inland waters—The number of components identified by PARAFAC modeling, and the spectral characteristics of the CDOM EEMs for the Yungui Plateau lakes,were similar to those found previously in aquatic environments(Table3[Cory and McKnight2005;Yamashita et al.2008;Kowalczuk et al. 2009]).For example,Stedmon et al.(2003)observed five peaks belonging to terrestrial and autochthonous organic matter in the Baltic Sea,including components with spectral characteristics that are comparable to those of components1and2found in the present study(Table3). The characteristics of the excitation and emission spectra of component2that we recorded fall in the transition zone between terrestrial and marine humic-like components (Stedmon et al.2003).Component2has excitation and emission maxima at shorter wavelengths than component 1,and is similar to peak M and peak N(Coble et al.1998), which are believed to belong to marine humic-like fluorophores or to be associated with phytoplankton productivity(Coble1996;Coble et al.1998;Wang et al. 2007).In a phytoplankton degradation experiment(Zhang et al.2009),a fluorescent component similar to component 2in the present study significantly increased,which supports the hypothesis that component2is of biological origin and is not exclusively a marine component.Further evidence that component2is derived from phytoplankton degradation can be deduced from the fact that there was a marked increase of component2in the transition from the mesotrophic to eutrophic state(from2.3960.67to5.856 1.61QSU).The increase of component2may be related to the significant increase in the Chl a concentration from the mesotrophic to the eutrophic lakes(from5.6964.32to 37.5626.7m g L21).
The peak position of component2(Ex max and Em max: 235(290)and397nm)was the result of blue-shifting (toward shorter wavelengths)of the Ex max and Em max peaks of component1(Ex max and Em max:255(350)and 471nm),which was dominated by the terrestrial humic-like fluorophore.This blue-shifting resulted from the increase of autochthonous humic substances from phytoplankton degradation(microbial activities;Boehme and Wells2006). Previously,Coble(1996)observed blue-shifting of a humic-like fluorescence peak,with Ex max and Em max of340nm and448nm in the river,342nm and442nm in the nearshore area,and310nm and423nm in the transition zone of a shallow sea.More recently,Her et al.(2003)and Boehme and Wells(2006)observed similar shifts in open-water areas compared to nearshore areas,due to the increase of autochthonous humic substances in the former location.
By using the relative contributions of the various components to the total fluorescence intensity as markers of CDOM properties,we have characterized a distinct CDOM fluorescence pattern in the Yungui Plateau lakes of each of the three different trophic states.For oligotro-phic lake waters,the CDOM fluorescence was dominated by the spectral characteristics of protein-like components (C3and C4),with minor contributions of humic-like components(C1and C2).Two protein-like components accounted for77.9%of the total fluorescence.These properties closely matched the CDOM fluorescence com-position of autochthonous production associated with biological degradation of CDOM(Coble et al.1998; Stedmon and Markager2005b).For mesotrophic lakes, the CDOM fluorescence was still dominated by the presence of the protein-like components(C3and C4 accounting for38.6%and27.3%,respectively).However, the contribution of humic-like components(C1and C2) increased significantly from22.0%to34.1%compared to oligotrophic lake waters.For eutrophic lake waters, the CDOM fluorescence was dominated by the humic-like components(C1and C2accounting for15.3%and 42.0%,respectively),and the protein-like components contributed only42.7%.These properties closely match the CDOM fluorescence composition of allochthonous input from the catchment,and from phytoplankton degradation(Coble et al.1998;Stedmon and Markager 2005b;Zhang et al.2009).However,we also note that autochthonous protein-like components still formed an important contribution to total fluorescence.
For lake waters of all three trophic states,the higher contribution of C2than C1suggests that a larger portion of the humic-like component was microbially(algal)derived rather than being derived from the surrounding catchment. Past similar results have been reported in alpine and subalpine lakes(Hood et al.2003;Miller et al.2009).For example,Hood et al.(2003)reported that the changes in the fluorescence properties of fulvic acids at the highest elevation sites,suggested that the DOC derived from algal and microbial biomass in the lakes was a more important source of DOC above the tree line during late summer and autumn than other seasons.
Significance of fluorescence indices—The characteristics of DOM(CDOM)associated with the values for each of the three established fluorescent indices are shown in Table5.In the present study,instead of254nm,255nm was used as excitation wavelength for one of the indices, because the EEMs of CDOM were measured at5-nm intervals for excitation.Therefore,the range of FI255values used to differentiate CDOM characteristics was slightly different from the FI254value in Table5.The low FI255
CDOM in lakes of the Yungui Plateau2655
values(0.23–6.00)reported here indicated that the CDOM in the Yungui Plateau lakes partly originated from autochthonous biological activity.The highest FI255values were associated with higher trophic state lakes,due to the increased contribution of terrigeneous humic fluorophores from the catchment,which is consistent with previous studies(Huguet et al.2009;Table5).The increase of humic components C1and C2with increasing trophic state (Fig.4)further demonstrates that FI255could be used to characterize CDOM source and composition.The corre-sponding range of FI255in Table5for CDOM in lakes of the Yungui Plateau should be,1.5,1.5–3,3–6,.6.The four values corresponded to CDOM with biological or aquatic bacterial origin;weak humic character and important recent autochthonous component;strong humic character and weak recent autochthonous component;and strong humic character and high terrigeneous contribution, respectively.The marked difference between the ranges of FI255and FI254reported by Huguet et al.(2009)was attributed to the following four aspects:(1)the different excitation wavelength(255nm vs.254nm);(2)the difference in filter pore(CDOM with the filter pore of 0.22m m vs.DOM with the filter pore of0.7m m);(3) instrument response correction(excitation correction vs.no excitation correction);and(4)water type(inland waters vs. estuarine waters).
The FI310values(0.60–1.54)in the present study fell into the range reported by Huguet et al.(2009),and could be used to differentiate between CDOM from oligotrophic and mesotrophic states.For eutrophic waters,the mean value of0.9060.14indicated CDOM from biological or aquatic bacterial origin(Fig.5).However,the EEMs and PARAFAC model showed the importance of CDOM of terrestrial origin in the eutrophic state.One possible interpretation of this inconsistency is that there were high rates of microbial production of CDOM,but that the spectral signal may have been masked by the more strongly fluorescing terrestrially derived humic CDOM.
FI370ranged from1.14to1.80,with a mean of1.376 0.12(CV58.6%)for all samples,which was similar to the value reported by McKnight et al.(2001).For oligotrophic Yungui lakes,the mean value of1.4060.13for FI370was similar to the value of1.4reported by McKnight et al. (2001)as indicative of terrestrially and microbially derived fulvic acids.From the oligotrophic to mesotrophic state, and further to the eutrophic state,FI370decreased, indicating the decrease of autochthonous CDOM.The significant decrease from1.4060.13to1.3260.10from the oligotrophic to the mesotrophic state,but no significant decrease from oligotrophic to eutrophic,or from mesotro-phic to eutrophic,were inconsistent with the result of EEM spectra and the PARAFAC model.
There were significantly positive correlations between FI310and FI370(p,0.001),and significant negative correlations between FI255and both FI310and FI370(p, 0.001),showing that the indication significance of FI310and FI370was similar.FI255was the only fluorescence index for which significant differences were found among the three different trophic states,suggesting that this index could best used to determine the effect of trophic state on CDOM.Furthermore,significant negative linear relation-ships were found between log-transformed altitude and both FI310and FI370,but no significant correlation between log-transformed altitude and FI255,suggesting that FI310 and FI370could be used to characterize the effect of altitude on CDOM,but FI255could not.Based on the above analysis,FI255,FI310,and FI370could be used in combina-tion to assess the effects of trophic state and altitude on CDOM sources and composition in the Yungui Plateau lakes.
Implications for the study of CDOM in lakes—Many studies,including the present one,have shown that CDOM absorption was the major factor determining attenuation of UVR in plateau and alpine lakes,and some empirical correlations have been developed to model UVR attenua-
Table5.DOM and CDOM characteristics associated with ranges of values for fluorescence indices FI254(Huguet et al.2009),FI255 (this study),FI310(Huguet et al.2009),and FI370(McKnight et al.2001).
Fluorescence index and range Characteristics
FI254for DOM FI255for CDOM
,4,1.5Biological or aquatic bacterial origin
4–6 1.5–3Weak humic character and important recent autochthonous
component
6–103–6Strong humic character and weak recent autochthonous component .16.6Strong humic character and high terrigeneous contribution FI310for DOM
0.6–0.7Low autochthonous component
0.7–0.8Intermediate autochthonous component
0.8–1Strong autochthonous component
.1Biological or aquatic bacterial origin
FI370for DOM
,1.4Terrestrially derived fulvic acids
1.4–1.9Terrestrially and microbially derived fulvic acids
.1.9Microbially derived fulvic acids
2656Zhang et al.
tion using CDOM absorption coefficients(Scully and Lean 1994;Laurion et al.1997;Huovinen et al.2003).The optical and fluorescence properties of CDOM,and its chemical composition and source,play a vital role in plateau and alpine lake ecosystems.Especially in clear oligotrophic lakes,small changes in CDOM absorption and specific absorption are likely to lead to major changes in the water-column UVR(Williamson et al.1996;Morris and Hargreaves1997),and in the biologically important UVR and visible spectral balance(Laurion et al.1997).
The ecosystems of plateau lakes are highly sensitivity to climate change due to the tight coupling between climate, catchments,and the biogeochemistry of lakes.Changes in climate,such as the ozone-layer–related increase in UV-B radiation,will affect the CDOM in lakes,which will in turn affect ecosystem structure and functioning,and thereby alter significant biogeochemical fluxes,such as the emission of CO2from lakes to the atmosphere(Zepp et al.2007; Tranvik et al.2009).The increase of CO2emission from photo-degradation of CDOM in lakes will affect global warming(Tranvik et al.2009).
Much of the above discussion is based on extrapolation of local measurements to a regional scale.It is,however, difficult to obtain data sets on UV-B attenuation and CDOM absorption for remote plateau and alpine lakes. Remote sensing is,therefore,a suitable alternative for providing more direct information on the CDOM distri-bution in these remote plateau and alpine lakes(Winn et al. 2009).If the appropriate sensors are flown,then the estimation of DOC concentrations and CO2emission of plateau lakes by remote sensing is possible,using regional correlations between CDOM and DOC,and CO2(Kutser et al.2005a,b).In summary,the study of CDOM in plateau lakes has potential applications not only in UV-B radiation attenuation,but also in global carbon cycle studies. Acknowledgments
X.Wang and R.Wang assisted with field work and laboratory analyses.We also thank the anonymous reviewers for their constructive comments and helpful suggestions.
This study was jointly funded by the National Natural Science Foundation of China(grants40971252,40825004,40730529, 40601099),the Major Projects on Control and Rectification of Water Body Pollution(2009ZX07101-013)and the Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-YW-QN312).
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Associate editor:Stephen P.Opsahl
Received:09April2010
Accepted:12August2010
Amended:07September2010
CDOM in lakes of the Yungui Plateau2659
尊重的素材（为人处世） 思路 人与人之间只有互相尊重才能友好相处 要让别人尊重自己，首先自己得尊重自己 尊重能减少人与人之间的摩擦 尊重需要理解和宽容 尊重也应坚持原则 尊重能促进社会成员之间的沟通 尊重别人的劳动成果 尊重能巩固友谊 尊重会使合作更愉快 和谐的社会需要彼此间的尊重 名言 施与人，但不要使对方有受施的感觉。帮助人，但给予对方最高的尊重。这是助人的艺术，也是仁爱的情操。—刘墉 卑己而尊人是不好的，尊己而卑人也是不好的。———徐特立 知道他自己尊严的人，他就完全不能尊重别人的尊严。———席勒 真正伟大的人是不压制人也不受人压制的。———纪伯伦 草木是靠着上天的雨露滋长的，但是它们也敢仰望穹苍。———莎士比亚 尊重别人，才能让人尊敬。———笛卡尔 谁自尊，谁就会得到尊重。———巴尔扎克 人应尊敬他自己，并应自视能配得上最高尚的东西。———黑格尔 对人不尊敬，首先就是对自己的不尊敬。———惠特曼
每当人们不尊重我们时，我们总被深深激怒。然而在内心深处，没有一个人十分尊重自己。———马克·吐温 忍辱偷生的人，绝不会受人尊重。———高乃依 敬人者，人恒敬之。———《孟子》 人必自敬，然后人敬之；人必自侮，然后人侮之。———扬雄 不知自爱反是自害。———郑善夫 仁者必敬人。———《荀子》 君子贵人而贱己，先人而后己。———《礼记》 尊严是人类灵魂中不可糟蹋的东西。———古斯曼 对一个人的尊重要达到他所希望的程度，那是困难的。———沃夫格纳 经典素材 1元和200元 （尊重劳动成果） 香港大富豪李嘉诚在下车时不慎将一元钱掉入车下，随即屈身去拾，旁边一服务生看到了，上前帮他拾起了一元钱。李嘉诚收起一元钱后，给了服务生200元酬金。 这里面其实包含了钱以外的价值观念。李嘉诚虽然巨富，但生活俭朴，从不挥霍浪费。他深知亿万资产，都是一元一元挣来的。钱币在他眼中已抽象为一种劳动，而劳动已成为他最重要的生存方式，他的所有财富，都是靠每天20小时以上的劳动堆积起来的。200元酬金，实际上是对劳动的尊重和报答，是不能用金钱衡量的。 富兰克林借书解怨 （尊重别人赢得朋友）
Source Insight实质上是一个支持多种开发语言（java,c ,c 等等） 的编辑器，只不过由于其查找、定位、彩色显示等功能的强大，常被我 们当成源代码阅读工具使用。 作为一个开放源代码的操作系统，Linux附带的源代码库使得广大爱好者有了一个广泛学习、深入钻研的机会，特别是Linux内核的组织极为复杂，同时，又不能像windows平台的程序一样，可以使用集成开发环境通过察看变量和函数，甚至设置断点、单步运行、调试等手段来弄清楚整个程序的组织结构，使得Linux内核源代码的阅读变得尤为困难。 当然Linux下的vim和emacs编辑程序并不是没有提供变量、函数搜索，彩色显示程序语句等功能。它们的功能是非常强大的。比如，vim和emacs就各自内嵌了一个标记程序，分别叫做ctag和etag，通过配置这两个程序，也可以实现功能强大的函数变量搜索功能，但是由于其配置复杂，linux附带的有关资料也不是很详细，而且，即使建立好标记库，要实现代码彩色显示功能，仍然需要进一步的配置（在另一片文章，我将会讲述如何配置这些功能），同时，对于大多数爱好者来说，可能还不能熟练使用vim和emacs那些功能比较强大的命令和快捷键。 为了方便的学习Linux源程序，我们不妨回到我们熟悉的window环境下，也算是“师以长夷以制夷”吧。但是在Window平台上，使用一些常见的集成开发环境，效果也不是很理想，比如难以将所有的文件加进去，查找速度缓慢，对于非Windows平台的函数不能彩色显示。于是笔者通过在互联网上搜索，终于找到了一个强大的源代码编辑器，它的卓越性能使得学习Linux内核源代码的难度大大降低，这便是Source Insight3.0，它是一个Windows平台下的共享软件，可以从https://www.doczj.com/doc/f15600788.html,/上边下载30天试用版本。由于Source Insight是一个Windows平台的应用软件，所以首先要通过相应手段把Linux系统上的程序源代码弄到Windows平台下，这一点可以通过在linux平台上将 /usr/src目录下的文件拷贝到Windows平台的分区上，或者从网上光盘直接拷贝文件到Windows平台的分区来实现。 下面主要讲解如何使用Source Insight，考虑到阅读源程序的爱好者都有相当的软件使用水平，本文对于一些琐碎、人所共知的细节略过不提，仅介绍一些主要内容，以便大家能够很快熟练使用本软件，减少摸索的过程。 安装Source Insight并启动程序，可以进入图1界面。在工具条上有几个值得注意的地方，如图所示，图中内凹左边的是工程按钮，用于显示工程窗口的情况；右边的那个按钮按下去将会显示一个窗口，里边提供光标所在的函数体内对其他函数的调用图，通过点击该窗体里那些函数就可以进入该函数所在的地方。
INF文件详解 INF文件格式要求 一个INF文件是以段组织的简单的文本文件。一些段油系统定义(System-Defined)的名称，而另一些段由INF文件的编写者命名。每个段包含特定的条目和命名，这些命名用于引用INF文件其它地方定义的附加段。 INF文件的语法规则： 1、要求的内容：在特定的INF文件中所要求的必选段和可选段、条目及命令依赖于所要安装的设备组件。端点顺序可以是任意的，大多数的INF文件安装惯用的次序来安排各个段。 2、段名：INF文件的每个段从一个括在方括号[]中的段名开始。段名可以由系统定义或INF编写者定义 在Windows 2000中，段名的最大长度为255个字符。在Windows 98中，段名不应该超过28个字符。如果INF设计要在两个平台上运行，必须遵守最小的限制。段名、条目和命令不分大小写。在一个INF文件中如果有两个以上的段有相同的名字，系统将把其条目和命令合并成一个段。每个段以另一个新段的开始或文件的结束为结束。 3、使用串标记：在INF文件中的许多值，包括INF编写者定义的段名都可以标示成%strkey%形式的标记。每个这样的strkey必须在INF文件的Strings 段中定义为一系列显示可见字符组成的值。 4、行格式、续行及注释：段中的每个条目或命令以回车或换行符结束。在条目或命令中，“\”可以没用做一个显示的续行符；分好“；”标示后面的内容是注释；可以用都好“，”分隔条目和命令中提供的多个值。 INF文件举例 下面是一个完整的.inf文件，它是Windows 2000 DDK提供的USB批量阐述驱动程序范例中所附的.inf文件。 ; Installation inf for the Intel 82930 USB Bulk IO Test Board ; ; (c) Copyright 1999 Microsoft ; [Version] Signature="$CHICAGO$" Class=USB ClassGUID={36FC9E60-C465-11CF-8056-444553540000} provider=%MSFT% DriverVer=08/05/1999 [SourceDisksNames] 1="BulkUsb Installation Disk",,, [SourceDisksFiles] BULKUSB.sys = 1 BULKUSB.inf = 1
安装完SI后，会在安装一个如下的文件 我的文档\Source Insight\c.tom c.tom的功能与C语言中的#define类似。打开这个文件，会看到有很多空格分割的字符串，SI在我们阅读代码时，自自动将空格前的字符串替换为空格后的字符串（仅仅是影响阅读，不影响编译喔）。 举两个例子。 #define AP_DECLARE(type) type AP_DECLARE(int) ap_calc_scoreboard_size(void) { .... } source insight 把AP_DECLARE当作了函数,当想查ap_calc_scoreboard_size的时候总是很麻烦,不能直接跳转. 我的文档\Source Insight\c.tom 加入 AP_DECLARE(type) type 如下的代码如何让SI 识别出f是一个函数？ #define EXPORT_CALL(return,functionname) return functionname EXPORT_CALL (int, f1()) 我的文档\Source Insight\c.tom 加入 EXPORT_CALL(return,functionname) return functionname 同时，在#define中，标准只定义了#和##两种操作。#用来把参数转换成字符串，##则用来连接前后两个参数，把它们变成一个字符串。（c.tom的功能与支持##，不支持#好像） 这个技巧我在阅读zebra的命令行代码时也用到了。 比如下吗一段代码:(DEFUN是一个宏定义，这个文件中有很多这样的DEFUN。不修改c.tom 之前看到的是这样的)
source命令与“.”点命令 source 命令是bash shell 的内置命令，从C Shell 而来。 source 命令的另一种写法是点符号，用法和source 相同，从Bourne Shell而来。 source 命令可以强行让一个脚本去立即影响当前的环境。 source 命令会强制执行脚本中的全部命令,而忽略文件的权限。 source 命令通常用于重新执行刚修改的初始化文件，如.bash_profile 和.profile 等等。source 命令可以影响执行脚本的父shell的环境，而export 则只能影响其子shell的环境。 使用方法举例： $source ~/.bashrc 或者： $. ~/.bashrc 执行后~/.bashrc 中的内容立即生效。 一个典型的用处是，在使用Android 的mm 等相关命令时，需要先执行以下命令：$cd
谈如何尊重人尊重他人，我们赢得友谊；尊重他人，我们收获真诚；尊重他人，我们自己也 获得尊重；相互尊重，我们的社会才会更加和谐. ——题记 尊重是对他人的肯定，是对对方的友好与宽容。它是友谊的润滑剂，它是和谐的调节器， 它是我们须臾不可脱离的清新空气。“主席敬酒，岂敢岂敢？”“尊老敬贤，应该应该！”共和 国领袖对自己老师虚怀若谷，这是尊重；面对许光平女士，共和国总理大方的叫了一 声“婶婶”，这种和蔼可亲也是尊重。 尊重不仅会让人心情愉悦呼吸平顺，还可以改变陌生或尖锐的关系，廉颇和蔺相如便是 如此。将相和故事千古流芳:廉颇对蔺相如不满，处处使难，但蔺相如心怀大局，对廉颇相 当的尊重，最后也赢得了廉颇的真诚心，两人结为好友，共辅赵王，令强秦拿赵国一点办法 也没有。蔺相如与廉颇的互相尊重，令得将相和的故事千百年令无数后人膜拜。 现在，给大家举几个例子。在美国，一个颇有名望的富商在散步 时，遇到一个瘦弱的摆地摊卖旧书的年轻人，他缩着身子在寒风中啃着发霉的面包。富 商怜悯地将8美元塞到年轻人手中，头也不回地走了。没走多远，富商忽又返回，从地摊上 捡了两本旧书，并说：“对不起，我忘了取书。其实，您和我一样也是商人！”两年后，富商 应邀参加一个慈善募捐会时，一位年轻书商紧握着他的手，感激地说：“我一直以为我这一生 只有摆摊乞讨的命运，直到你亲口对我说，我和你一样都是商人，这才使我树立了自尊和自 信，从而创造了今天的业绩??”不难想像，没有那一 句尊重鼓励的话，这位富商当初即使给年轻人再多钱，年轻人也断不会出现人生的巨变， 这就是尊重的力量啊 可见尊重的量是多吗大。大家是不是觉得一个故事不精彩，不够明确尊重的力量，那再 来看下一个故事吧！ 一家国际知名的大企业，在中国进行招聘，招聘的职位是该公司在中国的首席代表。经 过了异常激烈的竞争后，有五名年轻人，从几千名应聘者中脱颖而出。最后的胜出者，将是 这五个人中的一位。最后的考试是一场面试，考官们都 作文话题素材之为人处世篇：尊重 思路 人与人之间只有互相尊重才能友好相处 要让别人尊重自己，首先自己得尊重自己 尊重能减少人与人之间的摩擦 尊重需要理解和宽容 尊重也应坚持原则 尊重能促进社会成员之间的沟通 尊重别人的劳动成果 尊重能巩固友谊 尊重会使合作更愉快 和谐的社会需要彼此间的尊重 名言 施与人，但不要使对方有受施的感觉。帮助人，但给予对方最高的尊重。这是助人的艺 术，也是仁爱的情操。———刘墉 卑己而尊人是不好的，尊己而卑人也是不好的。———徐特立 知道他自己尊严的人，他就完全不能尊重别人的尊严。———席勒 真正伟大的人是不压制人也不受人压制的。———纪伯伦 草木是靠着上天的雨露滋长的，但是它们也敢仰望穹苍。———莎士比亚
Source Insight工程的说明 说明：source insight 是我们在工作中最常用到的软件，它对我们查找函数，变量，修改代码起到了不可估量的作用。熟练运用source insight可以提高工作效率，了解整个工程的架构是很有帮助的。 一source Insight工程的建立步骤 1、打开source insight 如下图所示：
2、工程目录的旁边建立一个文件夹，名字为code_s（文件夹名字自己可以为任意，最好能够区 分工程）。 3、在source insight里面，状态栏上，根据如下顺序，建立工程project- new project，点击后如 下图所示：
在上图中，new project name : 创建你要建立的source insight 工程的名字。例如我们创建为M53_code. Where do you want to stor the project data files? 是我们要将创建的工程文件放入的路径是什么？我们选择刚才我们创建的code_s文件夹的路径。最后如图所示。 4、按OK后，进入如下图所示的界面。 在这个界面里，所有的选项我们都默认，但是选择工程路径是我们需要建立的工程路径。例如我们现在要建立的工程路径是F:\M53\code那么，我们就要选择我们的工程路径。如图下图所示
5、按OK，进入下一个窗口。如图所示。 我们选择，后，如下图所示， 我们在前面全部选择，然后按OK。进行搜索源工程文件，搜索完成后，如图所示。 工程不同，文件的数量不同。这里有7472个文件。我们按确定后，按close,关闭上述窗口。工程建立成功。 二source insight 工程与源工程同步 在上述，工程建立之后，由于我们需要在source insight修改的时候，修改源工程，那么我们需
尊重他人的写作素材 导读：——学生最需要礼貌 著名数学家陈景润回厦门大学参加 60 周年校庆，向欢迎的人们说的第一句话是：“我非常高兴回到母校，我常常怀念老师。”被人誉为“懂得人的价值”的著名经济学家、厦门大学老校长王亚南，曾经给予陈景润无微不至的关心和帮助。陈景润重返母校，首先拜访这位老校长。校庆的第三天，陈景润又出现在向“哥德巴赫猜想”进军的启蒙老师李文清教授家中，陈景润非常尊重和感激他。他还把最新发表的数学论文敬送李教授审阅，并在论文扉页上工工整整写了以下的字：“非常感谢老师的长期指导和培养——您的学生陈景润。”陈景润还拜访了方德植教授，方教授望着成就斐然而有礼貌的学生，心里暖暖的。 ——最需要尊重的人是老师 周恩来少年时在沈阳东关模范学校读书期间 , 受到进步教师高盘之的较大影响。他常用的笔名“翔宇”就是高先生为他取的。周恩来参加革命后不忘师恩 , 曾在延安答外国记者问时说：“少年时代我在沈阳读书 , 得山东高盘之先生教诲与鼓励 , 对我是个很大的 促进。” 停奏抗议的反思 ——没有礼仪就没有尊重 孔祥东是著名的钢琴演奏家。 1998 年 6 月 6 日晚，他在汕头
举办个人钢琴独奏音乐会。演出之前，节目主持人再三强调，场内观众不要随意走动，关掉 BP 机、手提电话。然而，演出的过程中，这种令人遗憾的场面却屡屡发生：场内观众随意走动， BP 机、手提电话响声不绝，致使孔祥东情绪大受干扰。这种情况，在演奏舒曼作品时更甚。孔祥东只好停止演奏，静等剧场安静。然而，观众还误以为孔祥东是在渴望掌声，便报以雷鸣般的掌声。这件事，令孔祥东啼笑皆非。演出结束后，孔祥东说：有个 BP 机至少响了 8 次，观众在第一排来回走动，所以他只得以停奏抗议。 “礼遇”的动力 ——尊重可以让人奋发 日本的东芝公司是一家著名的大型企业，创业已经有 90 多年的历史，拥有员工 8 万多人。不过，东芝公司也曾一度陷入困境，土光敏夫就是在这个时候出任董事长的。他决心振兴企业，而秘密武器之一就是“礼遇”部属。身为偌大一个公司的董事长，他毫无架子，经常不带秘书，一个人步行到工厂车间与工人聊天，听取他们的意见。更妙的是，他常常提着酒瓶去慰劳职工，与他们共饮。对此，员工们开始都感到很吃惊，不知所措。渐渐地，员工们都愿意和他亲近，他赢得了公司上下的好评。他们认为，土光董事长和蔼可亲，有人情味，我们更应该努力，竭力效忠。因此，土光上任不久，公司的效益就大力提高，两年内就把亏损严重、日暮途穷的公司重新支撑起来，使东芝成为日本最优秀的公司之一。可见，礼，不仅是调节领导层之间关
尊重_议论文素材 "礼遇"的动力 --尊重可以让人奋发 日本的东芝公司是一家著名的大型企业，创业已经有90 多年的历史，拥有员工8 万多人。不过，东芝公司也曾一度陷入困境，土光敏夫就是在这个时候出任董事长的。他决心振兴企业，而秘密武器之一就是"礼遇"部属。身为偌大一个公司的董事长，他毫无架子，经常不带秘书，一个人步行到工厂车间与工人聊天，听取他们的意见。更妙的是，他常常提着酒瓶去慰劳职工，与他们共饮。对此，员工们开始都感到很吃惊，不知所措。渐渐地，员工们都愿意和他亲近，他赢得了公司上下的好评。他们认为，土光董事长和蔼可亲，有人情味，我们更应该努力，竭力效忠。因此，土光上任不久，公司的效益就大力提高，两年内就把亏损严重、日暮途穷的公司重新支撑起来，使东芝成为日本最优秀的公司之一。可见，礼，不仅是调节领导层之间关系的纽带，也是调节上下级之间关系，甚至和一线工人之间关系的纽带。世界知识产权日 --尊重知识 在2000 年10 月召开的世界知识产权组织第35 届成员国大会上，我国提议将 4 月26 日定为"世界知识产权日"。这个提案经世界知识产权组织成员国大会得到了确定。2001 年4 月26 日成为第一个"世界知识产权日"。这是我国尊重知识的具体表现。 屠格涅夫与乞丐 --尊重比金钱更重要 俄罗斯文豪屠格涅夫一日在镇上散步，路边有一个乞丐伸手向他讨钱。他很想有所施与，从口袋掏钱时才知道没有带钱袋。见乞丐的手伸得高高地等着，屠格涅夫面有愧色，只好握着乞丐的手说："对不起，我忘了带钱出来。"乞丐笑了，含泪说："不，我宁愿接受您的握手。" 孙中山尊重护士 --尊重不分社会地位 有一天，孙中山先生病了，住院治疗。当时，孙中山已是大总统、大元帅了。但是，他对医务人员很尊重，对他们讲话很谦逊。平时，无论是早晨或是晚间，每当接到护士送来的药品，他总是微笑着说声"谢谢您"，敬诚之意溢于言辞。 1925 年孙中山患肝癌，弥留之际，当一位护理人员为他搬掉炕桌时，孙中山先生安详地望着她，慈祥地说："谢谢您，您的工作太辛苦了，过后您应该好好休息休息，这阵子您太辛苦了! "听了这话，在场的人都泣不成声。 毛泽东敬酒 --敬老尊贤是一种美德 1959 年6 月25 日，毛泽东回到离别30 多年的故乡韶山后，请韶山老人毛禹珠来吃饭，并特地向他敬酒。毛禹珠老人说："主席敬酒，岂敢岂敢! "毛泽东接着说："敬老尊贤，应该应该。" 周恩来不穿拖鞋接待外宾 --衣着整齐体现对人的尊重 周恩来晚年病得很重，由于工作的需要，他还要经常接待外宾。后来，他病得连脚都肿起来了，原先的皮鞋、布鞋都不能穿，他只能穿着拖鞋走路，可是，有些重要的外事活动，他还是坚持参加。他身边的工作人员出于对总理的爱护和关心，对他说："您就穿着拖鞋接待外
[原创] WinCE中sources文件中targetlibs与sourcelibs的作用与区别[复制链接] wwfiney 当前离 线 最后登录2011-12-23 在线时间488 小时权威 71 金币 1455 注册时间2009-2-9 阅读权限200 帖子 1286 精华 4 积分 1707 UID 86 管理员 权威 71 金币 1455 阅读权限200 积分 1707 精华 4 电梯直达 主题贴 wwfiney 发表于2009-2-11 17:23:04 |只看该作者|倒序浏览 在WinCE里面，编译和链接的必备文件sources，做过WinCE BSP开发的一定都很熟悉，其中有2个关键字，targetlibs和sourcelibs，一直让我对其中的区别很感兴趣，故查阅了一些资料，与大家分享。 其实只要搜索以下就会得到一些基本的答案，比如： TARGETLIBS，如果一个库以DLL的形式提供给调用者，就需要用TARGETLIBS，它只链接一个函数地址，系统执行时会将被链接的库加载。比如coredll.lib就是这样的库文件。即动态链接。 SOURCELIBS，将库中的函数实体链接进来。即静态链接，用到的函数会在我们的文件中形成一份拷贝。 这个答案已经基本解决问题了，但是这个答案让我们能看到更深入的东西： This is componentization feature of Windows CE. The link has two steps. First, whatever is in SOURCELIBS gets combined in a signle library yourproductname_ALL.lib. In the second step, executable module is linked from that library and all the targetlibs. This is done to allow stubs to be conditionally linked: if the function is defined into your source already, stubs get excluded. If it is not there, stubbed version (returning ERROR_NOT_IMPLEMENTED or something to that effect) gets linked in instead. If the link were to be performed in just one step, it would be impossible to predict which version (real or stub) would get included. As it is, implemented functions have a priority over stubs. -- Sergey Solyanik Windows CE Core OS 总的来说就是先编译了你自己在sources里指定的源文件，在链接阶段，先将所有的sourcelibs链接在一起成为一个lib，然后与targetlibs指定的lib一起参与链接。 当然这里targetlibs指定的可以是dll的lib文件，在CE的帮助文件中，
关于尊重的论点和论据素材 关于尊重的论点 1.尊重需要理解和宽容。 2.尊重也应该坚持原则。 3.尊重知识是社会进步的表现。 4.尊重别人就要尊重别人的劳动。 5.尊重人才是社会发展的需要。 6.人与人之间需要相互尊重。 7.只有尊重别人才会受到别人的尊重。 8.尊重能促进人与人之间的沟通。 9.我们应该养成尊重他人的习惯。 10.对人尊重，常会产生意想不到的善果。 关于尊重的名言 1.仁者必敬人。《荀子》 2.忍辱偷生的人决不会受人尊重。高乃依 3.尊重别人的人不应该谈自己。高尔基 4.尊重别人，才能让人尊敬。笛卡尔 5.谁自尊，谁就会得到尊重。巴尔扎克 6.君子贵人而贱己，先人而后己。《礼记》 7.卑己而尊人是不好的，尊己而卑人也是不好的。徐特立 8.对人不尊敬，首先就是对自己的不尊敬。惠特曼
9.为人粗鲁意味着忘记了自己的尊严。车尔尼雪夫斯基 10.对人不尊敬的人，首先就是对自己不尊重。陀思妥耶夫斯基 11.对于应尊重的事物，我们应当或是缄默不语，或是大加称颂。尼采 12.尊重老师是我们中华民族的传统美德，我们每一个人都不应该忘记。xx 13.尊重劳动、尊重知识、尊重人才、尊重创造。《xx 大报告》 14.对别人的意见要表示尊重。千万别说：你错了。卡耐基 15.尊重人才，培养人才，是通用电器长久不败的法宝。杰克韦尔奇 16.君子之于人也，当于有过中求无过，不当于无过中求有过。程颐 17.施与人，但不要使对方有受施的感觉。帮助人，但给予对方最高的尊重。这是助人的艺术，也是仁爱的情操。刘墉 18.要尊重每一个人，不论他是何等的卑微与可笑。要记住活在每个人身上的是和你我相同的性灵。叔本华 19.要喜欢我们所不尊重的人是很难的;但要喜欢
sources文件详解 在Windows CE中，所有的驱动程序都以dll形式存在。Dll文件可以用EVC来开发，也可以使用PB来开发，使用PB开发驱动程序，可以跟NK同时进行编译，要比EVC来的方便一点。这篇文章就只要介绍用PB来进行dll库开发的方法。 使用PB来开发，首先应该在你的工作平台下面建立一个目录，用来存放源文件，同时要修改dir文件，使得编译的时候能够进到源文件所在的目录。 编写dll的方法这里就不说了，反正就是写一堆的函数，这里主要解释一下使用PB编译，需要增加的文件。 第一个文件是sources文件，这里给出了一个sources文件的例子： TARGETNAME=led 使用TARGETNAME来指示生成目标的文件名（不包含扩展名，扩展名PB会自动加上） RELEASETYPE=PLATFORM RELEASETYPE指示该文件将要生成的类型，一共有五个取值： SDK：使用该类型将使得生成的目标文件被存储 到%_PUBLICROOT%\Oak目录，而lib文件被放置
到%_PUBLICROOT%\Sdk目录 DDK：使用该类型将使得生成的目标文件被存储 到%_PUBLICROOT%\Oak目录，而lib文件被放置 到%_PUBLICROOT%\Ddk PLATFORM：使用该类型将使得生成的文件受平台控制LOCAL：该类型使得生成的文件全部放置到当前路径CUSTOM：该类型使得生成的文件放置到TARGETPATH 制定的位置（也就是说必须要有TARGETPATH参数设置）TARGETTYPE=DYNLINK 生成的目标类型，LIBRARY表示是一个lib库，DYNLINK 则表示是dll，而PROGRAM则是一个exe文件TARGETLIBS= $(_COMMONSDKROOT)\lib\$(_CPUINDPATH)\coredll.lib TARGETLIBS指示连接需要的库的名字 SOURCELIBS=mm.lib SOURCELIBS指示将于某一个lib一起连接。上面一个lib 是需要什么就取什么，而这个lib则是连接所有的。DEFFILE=led.def DLL文件的def文件名 INCLUDES=..\..\inc 指定include的路径 SOURCES=
关于学会尊重的高中作文1000字以上 尊重是一杯清茶，只有真正懂它的人才能忽略它的寡淡，品出它深处的热烈。下面橙子为大家搜集整理有关学会尊重的高中作文，希望可以帮助到大家! 高中作文学会尊重曾经听说这样一个故事： 一位商人看到一个衣衫破烂的铅笔推销员，顿生一股怜悯之情。他不假思索地将10元钱塞到卖铅笔人的手中，然后头也不回地走开了。走了没几步，他忽然觉得这样做不妥，于是连忙返回来，并抱歉地解释说自己忘了取笔，希望不要介意。最后，他郑重其事地说：“您和我一样，都是商人。” 一年之后，在一个商贾云集、热烈隆重的社交场合，一位西装革履、风度翩翩的推销商迎上这位商人，不无感激地自我介绍道：“您可能早已忘记我了，而我也不知道您的名字，但我永远不会忘记您。您就是那位重新给了我自尊和自信的人。我一直觉得自己是个推销铅笔的乞丐，直到您亲口对我说，我和您一样都是商人为止。” 没想到商人这么—句简简单单的话，竟使一个不无自卑的人顿然树立起自尊，使—个处境窘迫的人重新找回了自信。正是有了这种自尊与自信，才使他看到了自己的价值和优势，终于通过努力获得了成功。不难想象，倘若当初没有那么—句尊重鼓励的话，纵然给他几千元也无济于事，断不会出现从自认乞丐到自信自强的巨变，这就是尊1 / 7
重，这就是尊重的力量! 尊重，是—种修养，一种品格，一种对别人不卑不亢的平等相待，一种对他人人格与价值的的充分肯定。任何人都不可能尽善尽美，完美无缺，我们没有理由以高山仰止的目光审视别人，也没有资格用不屑一顾的神情去嘲笑他人。假如别人在某些方面不如自己，我们不能用傲慢和不敬去伤害别人的自尊;假如自己在有些地方不如他人，我们不必以自卑或嫉妒去代替理应有的尊重。一个真正懂得尊重别人的人，必然会以平等的心态、平常的心情、平静的心境，去面对所有事业上的强者与弱者、所有生活中的幸运者与不幸者。 尊重是一缕春风，一泓清泉，一颗给人温暖的舒心丸，一剂催人奋进的强心剂。它常常与真诚、谦逊、宽容、赞赏、善良、友爱相得益彰，与虚伪、狂妄、苛刻、嘲讽、凶恶、势利水火不容。给成功的人以尊重，表明了自己对别人成功的敬佩、赞美与追求;表明了自己对别人失败后的同情、安慰与鼓励。只有要尊重在，就有人间的真情在，就有未来的希望在，就有成功后的继续奋进，就有失败后的东山再起。 尊重不是盲目的崇拜，更不是肉麻的吹捧;不是没有原则的廉价逢迎，更不是没有自卑的低三下四。懂得了尊重别人的重要，并不等于学会了如何尊重别人，从这个意义上说，尊重他人也是一门学问，学会了尊重他人，就学会了尊重自己，也就学会和掌握了人生的一大要义。 2 / 7
2015年高考作文素材：关于文明的作文素材 高考作文素材点拨及运用思路：文明 一、素材链接: 言语类 (一)名人名言 1.礼仪的目的与作用本在使得本来的顽梗变柔顺，使人们的气质变温和，使他尊重别人，和别人合得来。约翰?洛克 2.善气迎人，亲如弟兄;恶气迎人，害于戈兵。管仲 3.天下有大勇者，猝然临之而不惊，不故加之而不怒。苏轼 4.我们应该注意自己不用言语去伤害别的同志，但是，当别人用语言来伤害自己的时候，也应该受得起。刘少奇 5.礼貌使人类共处的金钥匙。松苏内吉 6.讲话气势汹汹，未必就是言之有理。萨迪 7.火气甚大，容易引起愤怒底烦扰，是一种恶习而使心灵向着那不正当的事情，那是一时冲动而没有理性的行动。彼得.阿柏拉德 8.青年人应当不伤人，应当把个人所得的给予各人，应当避免虚伪与欺骗，应当显得恳挚悦人，这样学着去行正直。夸美纽斯 9.礼貌是儿童与青年所应该特别小心地养成习惯的第一件大事。约翰.洛克 10.不论你是一个男子还是一个女人，待人温和宽大才配得上人的名称。一个人的真 11.正的英勇果断，决不等于用拳头制止别人发言。萨迪 12.礼貌使有礼貌的人喜悦，也使那些授人以礼貌相待的人们喜悦。孟德斯鸠 13.坏事情一学就会，早年沾染的恶习，从此以后就会在所有的行为和举动中显现出来，不论是说话或行动上的毛病，三岁至老，六十不改。克雷洛夫 14.礼貌经常可以替代最高贵的感情。梅里美 15.礼貌是最容易做到的事，也是最珍贵的东西。冈察尔 16.脾气暴躁是人类较为卑劣的天性之一，人要是发脾气就等于在人类进步的阶梯上倒退了一步。达尔文 17.蜜蜂从花中啜蜜，离开时营营的道谢。浮夸的蝴蝶却相信花是应该向他道谢的。泰戈尔
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写尊重的初中素材作文 学会尊重 曾看过一个《尊重》的故事：一个商人看到一个衣衫褴褛的铅笔推销员，不假思索地 将10元塞进卖铅笔人的手中，当做施舍。走了没几步，他觉得这样做不妥，连忙返回来，抱歉地向卖铅笔人解释自己忘了取笔。最后郑重其事地说：“您和我一样，都是商人。” 没想到的是，在一年后，在一个热烈隆重的社交场合上，一位西装革履的推销商迎上这位 商人，感激地说：“您可能早已忘记我，但我永远也不会忘记您。您就是那位重新给了我 自尊和自信的人。” 尊重，其实并不难，而在于学会怎样去尊重别人。如果这位商人只是施舍10元后便 离开，那个卖铅笔人也许到今天还认为自己是一个乞丐，也就不会有今天的成就。而这位 商人意识到了那样做是把卖铅笔人看做乞丐，是不尊重他的行为。所以他立即返回，抱歉 地取回铅笔，把卖铅笔人看做和自己一样是商人，应当得到平等的待遇，受到尊重。这虽 然只是一句普通的话，但给予了卖铅笔人的，又岂只是10元，更重要的是自尊和自信， 使得他对自己改变了看法，重塑自尊心，使一个一贫如洗的人看到了自己的优势和价值， 凭艰苦奋斗和自强不息的努力获得了事业的成功，这就是尊重的力量。 我们需要尊重 我们十四岁，风华正茂;我们十四岁，热情奔放。十四岁的我们，尊重别人，同样也 需要别人尊重。 十四岁是一个多思的年华。在生活中，我们学会了思考。看到世间万物，芸芸众生， 我们都要想一想，于是就出现了---日记本。 今天不上晚自习，我没有预先告诉妈妈，想给她一个惊喜。 我轻手轻脚的上了楼，门是虚掩着的，我从门缝往里一看，妈妈正在我的抽屉里翻着 什么。天哪!我的日记本! 我冲了进去，大叫一声:"妈妈!" 妈妈惊讶的转向我，手里的日记本滑落到了地上，手足无措地说:"你，你今天怎么就，就回来了。我，我到你房间打扫卫生，看你抽，抽屉没关好，就¨¨¨" 我气愤地看着满脸惊慌的妈妈，用怨恨的目光瞪了她一眼，就跑出去了。 夕阳淡淡的，忧伤的晚霞笼罩着大地江河。我独自来到桥上，望着点点金光闪烁的河面，心里久久不能平静。
【篇一】高考作文素材 1.关爱得到尊重 懂得关爱别人的人是受世人尊敬的。以前有个加拿大科学家在做实验时，不小心使两块铀移动了，并且相互冲了过去。若这两块铀相接触，其威力不亚于一颗小原子弹的爆炸。就在这危急的时刻，科学家用自己的双手，硬是把这两块铀掰开了。 一次危机渡过了，可这位科学家也因受到太多辐射，而不幸以身殉职。政府为了表彰其伟大的博爱精神，而授予了他"用手分开原子弹的人"的称号。他用他伟大的爱，无私地关爱别人，关爱全人类，他赢得了人们对他永恒的敬佩和赞叹。 【篇二】高考作文素材 2.诺基亚的成功 一个企业置身商界犹如一个人置身社会，其生命的旅途中，形形色色的诱惑是很多的，也是容易走上歧途的，可贵的是世界企业一旦认准了属于自己的一点之后，不仅能抗拒诱惑，而且为了将全部力量集中在这一点上，敢于舍弃其他的一切，最典型的例子是诺基亚。1990年的诺基亚，因产业领域过宽而濒于破产，后来老总决定只认准一点--手机，将其他产业全部舍弃(包括卖掉一个年利润800万美元的制药厂)，5年后它便东山再起了。 【篇三】高考作文素材 3.蚂蚁的启示 蚂蚁给了我们许多启示--团结就是力量，永不气馁等。这里我也来讲一个关于蚂蚁的故事：两只蚂蚁想到墙那边去找食物，一只蚂蚁顺着墙往上爬，刚爬到一半就掉下来了，如此反复了几次。另一只蚂蚁看到这种情况，就绕过墙到了另一边，等到第一只蚂蚁爬过墙时，那只蚂蚁已将食物吃完了。第一只蚂蚁秉着那永不气馁、永不放弃的"美德"让自己失去了食物。 这种事不仅发生在头脑简单的蚁国，在我们发达的人类社会里也屡见不鲜：一些作家一味地总结自己的成功经验，结果让自己以后的作品与以前的作品一个风格，毫无创新，毫无新意。这难道不是一种不放弃的悲哀D愫蒙以说放弃就是新的突破，是超越自我的前提。轻言放弃是弱者，不言放弃是愚者，懂得如何放弃才是智者。
尊重人才，我们要做的还有很多 中共中央、国务院近日印发了《国家中长期人才发展规划纲要（2020－2020年）》，纲要确立了我国2020年跻身世界人才强国行列这一目标，这的确令人欣喜。而面对我国当前的人才现状，如何能够保证这一目标的实现呢？我们不妨先讲一个关于人才的故事：1929年，年仅26岁的冯·诺依曼接到了普林斯顿大学的一封客座教授聘书，并承诺如果他愿意留在美国定居，将增加薪金并一年以后聘为正式教授，这意味着更加优厚的研究条件和待遇。此时的他，不过是汉堡大学的一个兼职讲师，不过这并不是因为他水平不够，恰恰相反，此时的他在学术界已经声名鹊起。但当时德国大学的学术体系更在乎资历和行政官员的评价，毫无疑问，博士毕业仅仅三年的诺依曼很难有很大的发挥空间。 于是诺依曼欣然接受邀请，远赴美国，并与爱因斯坦一同成为普林斯顿大学高级研究院的首批教授。在其后来的学术生涯中，他创造性地提出“二进制”和“程序内存”思想，被称为“计算机之父”。 诺依曼的故事，是美国人才战略的一个经典案例。而与他几乎同时，有一大批欧洲科学家因国籍、种族、血统、出生地、资历等原因，离开欧洲奔赴美国，这其中不乏爱因斯坦、“中子物理学之父”费米、“火箭之父”冯·卡门、“氢弹之父”爱德华·泰勒等顶级科学家，这对于奠定美国世界头号强国地位，无疑有着举足轻重的推动作用。 诺依曼等一大批科学家的经历，非常值得我们思考。不拘一格，尊重人才，是美国得以吸引这些人才的重要原因。而尊重人才，不单单是一句话，而是一个体系，涵盖了人才强国战略的方方面面。正如胡锦涛总书记所言，要切实做好人才服务各项工作，努力为人才发展营造良好环境。 服务人才工作，最重要的莫过于做到人尽其才，能够让其通过自身努力取得成就，这是吸引人才、留住人才的最好方式，即“用事业聚才育才”。而要发挥才能，取得成就，就必须拥有一个充分发挥才干的空间和平台，即“创业有机会、干事有舞台、发展有空间”，如果德国的大学能够不囿于传统的学术资历，给诺依曼一个更大的空间，那么也不会失去这样一个杰出的人才。 除此之外，对于人才还应给予足够的宽容，要鼓励创新、爱护创新，使一切创新想法得到尊重、一切创新举措得到支持、一切创新才能得到发挥、一切创新成果得到肯定，营造鼓励创新、容许失误的工作环境。杨振宁曾经这样评价“氢弹之父”泰勒：“泰勒几乎每天都有十个新想法，其中有九个半是错误的，但他并不在乎，而是以非凡的勇气对那半个正确的想法进行大胆的创新。正是凭着每天半个正确想法的创新积累，泰勒博士获得了巨大的成功。”这无疑也是值得我们思考和借鉴的。 营造良好工作环境之外，还应当在生活上免除人才的后顾之忧，正如温家宝总理所言，要关心和改善人才的生活条件，解决好他们在住房、医疗、就业、子女教育、社保等方面的实际问题。这同样是服务于人才工作。 上世纪初的美国，科技创新实力远远落后于欧洲，然而正是因为其采用了正确的人才战略，得以一举跃升成为世界头号科技强国。如今我国的发展正处在转型关键时期，唯有不拘一格培育人才，发掘人才，才能进一步提高自主创新能力，实现民族伟大复兴。