Characterization of Colored Dissolved Organic Matter (CDOM) in surface and ground waters in South Florida was conducted using fluorescence and absorption spectroscopy. Waters of the West Florida Shelf are heavily influenced by many river systems on Florida's Gulf Coast that, to the first order control CDOM distributions on the shelf. Seasonal surveys revealed that changes in the underwater light field as a result of major hurricanes and resuspension events are linked closely with a number of factors prior to a storm's passing such as the presence of persistant blooms, rainfall and discharge. Additionally, storm track and wind direction were found to play a significant role in CDOM signatures. A study of ten riversheds located between the Mississippi / Atchafalya River system and the Shark River in the Everglades revealed a wide range in CDOM seasonality. A regional dependence of CDOM was also found, where highest aromaticity and concentration of organic material was found for the southernmost watersheds. Basin characteristics, vegetation differences, land use and climatic patterns are implicated in the cause for regional differences. In addition to surface flow, organic material in groundwater was measured in deep and shallow aquifers surrounding the Tampa Bay Estuary. As a result of strong hydrologic links between shallow aquifers and the overlying surface waters, CDOM in both reservoirs were found to be quite similar. Deep aquifers (> 150 ft) however are less concentrated and have CDOM signatures more similar to marine waters. This suggests similar biogeochemical pathways of the material, including the influence of the aquatic microbial community. Furthermore, multi-spectral CDOM fluorescence measurements were shown to be a potential indicator of groundwater presence in Tampa Bay during times of low surficial discharge to the bay, and when some rivers are almost entirely spring-fed. Investigating CDOM distribution and signatures is vital to carbon budget and cycling questions. The amount and quality of organic material has significant implications for ecosystems, thereby affecting organisms that use CDOM as a food source, light availability for photosynthesis, UV shading provided to biota, satellite estimates of chlorophyll a, metal binding, materials transport and overall water quality.

The global carbon cycle is intimately linked with the earth’s climate system. Knowledge about carbon cycling in the biosphere is therefore crucial for predictions of climate change. This thesis investigates the carbon dioxide balance of Swedish boreal lakes, its regulation, significance to the carbon budget of the boreal landscape, and sensitivity to climate change. Swedish boreal lakes were almost exclusively supersaturated in CO2 with respect to the atmosphere, resulting in an emission of CO2 from lakes to the atmosphere. Lake pCO2 was closely related to the concentration of terrigenous dissolved organic carbon (DOC), indicating that the utilization of terrigenous DOC by lake bacteria is a major source of CO2. This conclusion is supported by independent field studies, showing that net plankton respiration accounts for most of the CO2 emitted from Swedish boreal lakes, while photochemical mineralization and sediment respiration were less important. Mineralization of terrigenous DOC and subsequent emission of CO2 from lakes to the atmosphere was a major carbon loss factor in 21 major Swedish boreal catchments, removing 30-80% of the organic carbon exported from terrestrial soils to surface waters. Lake CO2 emission is in the same order of magnitude as organic carbon accumulation in boreal forest soils, and should therefore be included in the carbon budget of the boreal landscape. In a set of nearly 5000 global lakes, DOC concentration was a much more important regulator of lake pCO2 than temperature. Climate change will therefore affect the carbon balance of lakes primarily via alterations in terrestrial DOC export, rather than via changes in temperature per se. Both current observations and models of future climate suggest an increasing export of terrigenous DOC from many Scandinavian catchments. Hence, there probably is a current trend towards higher CO2 emission from Swedish boreal lakes, which is likely to continue in the future.

Two small bordering catchments in Bispgården, Central Sweden, wereinvestigated in regard to soil solution and stream water chemistry during the frostfree seasons of 2003-2007. Both catchments were drained by first order streams,Fanbergsbäcken and Gråbergsbäcken, and in Fanbergsbäckens catchment anextensive investigation of the soil and soil solution chemistry was conducted bylysimeter and centrifugation sampling. The area of intensive soil solutioninvestigation was situated in a slope towards a stream incorporating a rechargearea, with podzolic soil, and a discharge area close to the stream with an arenosolsoil. Samples were continuously taken in both the recharge- and the discharge areaof the slope, and stream water was sampled in the streams of both catchments. Themain variables of interest of the study were the interactions, the influence ofdissolved organic carbon and the effects of wood ash application to soil solutionand stream water.The natural variations and the interactions between soil solution and streamwater were monitored during 2003-2004. In soil solution, most of the investigatedsubstances tended to increase during the growing season, due to weathering andmicrobial degradation of biota. Ca, Mg, Al and Fe were highly associated todissolved organic carbon (DOC) throughout the catchment. The low molecularfraction of DOC seemed to have a higher impact on the soil processes in therecharge area, while high molecular DOC was more important for transport ofcations in the discharge area and the stream water.The concentration of different substances in the two streams differedsignificantly, even though the catchments were similar in size, shape andforestation. The seasonal patterns of most of the substances measured weresignificantly correlated between the streams, however. Cations and pH correlatedwell with DOC and flow. The flow pattern driven by precipitation seems to be thedriver of the stream water chemistry.Wood ash was applied at a dosage of 3 ton/ha to one of the catchments in theautumn of 2004, to investigate the initial effects on the soil solution- and streamwater chemistry. WAA is recommended by the Swedish Forest Agency tocounteract acidification in soil and runoff that may be caused by an intensivebiomass harvesting. The impact of the WAA was studied during 2005-2006.Compared to the control temporarily higher concentrations of K, Ca and SO4 wereobserved in the soil solution of the ashed area. In the stream water the effects of theWAA were easier to distinguish due to higher sampling frequency. The strongesteffect was seen for K, but increases in the stream water were also noted for DOC,Ca, Mg, Si, Cl and malonate. No increase in pH could be statistically verifiedhowever, and overall the initial effects of the WAA seem mild. / Två angränsande avrinningsområden i Bispgården i centrala Sverigeundersöktes under den snöfria säsongen 2003-2006. Båda avrinningsområdenadränerades av första ordningens bäckar och i det ena, Fanbergsbäckensavrinningsområde, gjordes en omfattande undersökning av mark och markvattenkemin.Markvatten provtogs genom centrifugering och med lysimetrar.Provtagningen gjordes i inströmningsområdet där jordmånen var en typiskpodzol samt närmare bäcken, i utströmningsområdet, där jordmånen var enarenosol. Bäckvatten provtogs i båda avrinningsområdena. Interaktioner mellanmark, markvatten och bäckvatten undersöktes med särskilt fokus på inverkan avorganiskt kol samt påverkan av askåterföring.De naturliga variationerna i markkemin samt interaktionerna mellan mark- ochbäck vatten undersöktes 2003-2004. I markvatten ökade merparten av de studeradeämnena under provtagningssäsongen beroende av ökad vittring och recirkulationav biota och fallförna. Ca, Al och Fe var i stor utsträckning associerade till löstorganiskt kol (DOC). Den lågmolekylära fraktionen av DOC hade en störreinverkan på markprocesserna i inströmningsområdet, medan den högmolekyläradelen var viktigare för transport av katjoner i utströmningsområdet samt ibäckvattnet.Koncentrationsnivåerna av olika substanser i bäckarna uppvisade skillnadertrots avrinningsområdenas yttre likheter med avseende på storlek, form ochbeskogning. Trots de kvantitativa skillnaderna erhölls emellertid liknandesäsongsvariationer i koncentrationerna, vilket indikerade att kemin i huvudsakstyrdes av mängden DOC som i sin tur berodde av avrinningen som drevs avnederbörden. Höga halter av Ca, Mg, Al och Fe återfanns associerade tillhögmolekylärt DOC i bäckvattnet i en utsträckning som inte rapporterats tidigare.På hösten 2004 spreds 3 ton aska/ha till Fanbergsbäckens avrinningsområde föratt undersöka de initiala effekterna på mark- och bäckvatten kemin. Askåterföringbör ske minst en gång per omloppstid vid helträdsavverkning, i enlighet medSkogsstyrelsens rekommendationer, främst för att motverka försurning i mark ochavrinnande vatten som antas uppstå vid intensivt uttag av biomassa. De initialaeffekterna av askåterföringen på mark- och bäckvattnets kemi studerades under2005-2006 och Gråbergsbäcken kunde användas som obehandlad kontroll vidundersökning av vattenkemin i Fanbergsbäcken. I undersökningen av markvattenviåterfanns stora säsongsvariationer, vilket gjorde det svårt att urskilja eventuellaeffekter av askåterföringen. Tillfälligt högre värden av K, Ca och SO4 återfannsdock i det askade området i jämförelse med kontrollområdet. På grund av högreprovtagningsfrekvens i bäckvattnet var det lättare att påvisa förändringar ibäckvatten kemin. Framförallt märktes en signifikant ökning av K jämfört medkontrollbäcken. Sådana ökningar, om än inte lika markanta återfanns också förDOC, Ca, Mg, Si, Cl och malonat. En tendens till ökat pH kunde observeras, mendenna kunde inte verifieras statistiskt. De initiala effekterna av askåterföringen varsåledes till synes milda, och den eftertraktade pH-effekten erhölls ej i dennaundersökning.

Inland waters have long been neglected in the global carbon cycle. They represent only 2,8% of the land area, but it has come clear that inland waters play a key role in the transformation of terrestrial fixed carbon to the atmosphere. Human activities do have an impact on the carbon cycling and it is important to understand how these changes affects natural biogeochemical and climatological processes. The purpose of this report was to investigate how forestry impacts the emission of carbon dioxide from boreal lakes and to evaluate which role lakes play in the global carbon cycle. The study was accomplished as a literature study and the search words that have been used are carbon cycling, carbon dioxide, forestry, boreal lakes, dissolved organic carbon and pCO2. The results show that in many studies does forestry increase the export of dissolved organic carbon from terrestrial environments to boreal lakes. This increase subsidies the net heterotrophy in boreal lakes, making them net sources of carbon dioxide to the atmosphere. The processes behind increased concentrations and emissions are however complex and factors like local topography, hydrology and climate are thought to have impacts on how much carbon dioxide that is produced at a given level of dissolved organic carbon. Forestry seems to have an increasing effect on the carbon dioxide emissions, but the key drivers behind this process are expressed differently between regions and the reasons underlying these differences remain to be explored in order to make precise global carbon models.

I analyzed the 21 year dynamics of dissolved organic carbon (DOC) in 55 lakes in five sites across Eastern Canada in relation to regional and global variables. Regional variables included total solar radiation (TSR), precipitation (PPTN), air temperature (T) and sulfate deposition (SO4). Global variables included the Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation (PDO). A synchronous pattern in DOC was found among lakes within each region; however, a synchronous pattern in DOC was not found between sites, except for Kejimkujik and Yarmouth which were only 80 km apart from each other. This suggested that the variation of the long-term DOC pattern was in response to the temporal pattern of regional variables, and it supports the recent understanding that regional factors have a strong influence on many lake properties. Significant long-term trends in DOC were not evident except at the Experimental Lakes Area (ELA), where an increase in DOC was observed together with a decrease in summer TSR and an increase in summer precipitation. Annual mean air temperature has increased at the Nova Scotia and Turkey lakes sites over the study period. The relationship between the long-term pattern in DOC with the regional and global variables was analyzed for each study site to determine the key variables that could best explain the variation in the long-term pattern in DOC. TSR and PPTN were important independent variables across all sites, except for the Turkey Lakes Watershed site (TLW). Summer TSR (annual TSR for Kejimkujik and Yarmouth) had a negative relationship, while summer precipitation had a positive relationship with the long-term DOC pattern for all sites except TLW. TSR and PPTN explained 78%, 49% and 84% of the variation in the long-term DOC pattern at Dorset, ELA, and Nova Scotia (NS) sites, respectively. In contrast, the long-term pattern in DOC at TLW only had a weak relationship with the regional and global variables considered. A General model was developed to compare the strength of the response of DOC to the regional variables among sites. Therefore, only the variables which had a significant linear correlation with DOC across sites were selected. If a site had no variables in common with other sites, it was excluded from the general model. This resulted in TLW being excluded from the general model because the long-term DOC pattern at TLW was not significantly correlated with any regional variables. The best general model included TSR from Dorset, ELA and NS sites and precipitation from only the NS site. The strengths of the response of DOC to precipitation were weak at Dorset and ELA compared to NS, therefore, they were excluded. The general model explained 91% of the site-to-site variation of DOC among sites. Among them, TSR was an important negative variable which contributed 56% of the explanation to the general model. Precipitation at NS was an important positive variable for the general model. It contributed 34% of the explanation to the model. As the response of the long-term DOC pattern to the changes of environmental variables (TSR and PPTN) was very strong at NS, the NS site dominated the general model, and its temporal (year-to-year) variation in the long-term DOC pattern explained 60% of the site-to-site variation of DOC in Eastern Canada. The other two sites, Dorset and ELA, had weak contributions (20% and 11%, respectively) to the general model.

Understanding the mechanisms of non-point source carbon and nutrients in urban watersheds will help to develop policies to maintain surface water quality and prevention of eutrophication. The purpose of this dissertation is to investigate the impact of sodium on carbon and nutrient leaching from the two main contributors; soil and leaf litter, and calculate the sodium exports in a humid subtropical urban river basin. The first chapter reviews the current literature on urbanization in watersheds. Chapter II quantifies the carbon and nutrient in intact soil core leachates and in water extractable solution from urban soils collected from 33 towns and cities across the state of Texas. Chapter III investigates the impact of sodicity and salinity on water extractable organic carbon and nitrogen from vegetation. Chapter IV investigates the export of sodium and chloride from the upper Trinity River basin. The results derived from this study indicate that sodium exports are elevated in urban watersheds and further that sodium in irrigation water elevates the loss of carbon and nutrients from both watershed soil and senesced vegetation and that this may contribute to high concentrations in urban freshwaters.

I analyzed the 21 year dynamics of dissolved organic carbon (DOC) in 55 lakes in five sites across Eastern Canada in relation to regional and global variables. Regional variables included total solar radiation (TSR), precipitation (PPTN), air temperature (T) and sulfate deposition (SO4). Global variables included the Southern Oscillation Index (SOI), North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation (PDO). A synchronous pattern in DOC was found among lakes within each region; however, a synchronous pattern in DOC was not found between sites, except for Kejimkujik and Yarmouth which were only 80 km apart from each other. This suggested that the variation of the long-term DOC pattern was in response to the temporal pattern of regional variables, and it supports the recent understanding that regional factors have a strong influence on many lake properties. Significant long-term trends in DOC were not evident except at the Experimental Lakes Area (ELA), where an increase in DOC was observed together with a decrease in summer TSR and an increase in summer precipitation. Annual mean air temperature has increased at the Nova Scotia and Turkey lakes sites over the study period. The relationship between the long-term pattern in DOC with the regional and global variables was analyzed for each study site to determine the key variables that could best explain the variation in the long-term pattern in DOC. TSR and PPTN were important independent variables across all sites, except for the Turkey Lakes Watershed site (TLW). Summer TSR (annual TSR for Kejimkujik and Yarmouth) had a negative relationship, while summer precipitation had a positive relationship with the long-term DOC pattern for all sites except TLW. TSR and PPTN explained 78%, 49% and 84% of the variation in the long-term DOC pattern at Dorset, ELA, and Nova Scotia (NS) sites, respectively. In contrast, the long-term pattern in DOC at TLW only had a weak relationship with the regional and global variables considered. A General model was developed to compare the strength of the response of DOC to the regional variables among sites. Therefore, only the variables which had a significant linear correlation with DOC across sites were selected. If a site had no variables in common with other sites, it was excluded from the general model. This resulted in TLW being excluded from the general model because the long-term DOC pattern at TLW was not significantly correlated with any regional variables. The best general model included TSR from Dorset, ELA and NS sites and precipitation from only the NS site. The strengths of the response of DOC to precipitation were weak at Dorset and ELA compared to NS, therefore, they were excluded. The general model explained 91% of the site-to-site variation of DOC among sites. Among them, TSR was an important negative variable which contributed 56% of the explanation to the general model. Precipitation at NS was an important positive variable for the general model. It contributed 34% of the explanation to the model. As the response of the long-term DOC pattern to the changes of environmental variables (TSR and PPTN) was very strong at NS, the NS site dominated the general model, and its temporal (year-to-year) variation in the long-term DOC pattern explained 60% of the site-to-site variation of DOC in Eastern Canada. The other two sites, Dorset and ELA, had weak contributions (20% and 11%, respectively) to the general model.

According to the literature, the deterioration of water quality in pipeline networks of water distribution is not solely due to the deterioration of raw water quality outlet from water treatment plants, but primarily due to the multiplication of microorganisms in water distribution pipelines, a phenomenon known as after-growth or re-growth. Presently, the most effective method of a biological stability in treated water for controlling microbial re-growth is by limiting nutrients, including nitrogen, phosphorus, and organic carbon. The content of assimilable organic carbon (AOC) within organic carbon is considered to be the most main factor for controlling the growth of microorganisms in the water distribution systems. The objects of this work were to study the Cheng Ching Lake Water Treatment Plant (CCLWTP) in Kaohsiung and the Gong Yuan Water Treatment Plant (GYWTP) in Chiayi. Water samples were collected once a month from December 2008 to November 2009. The major difference between the study objects was that front one is an advanced water treatment plant, and the other a traditional one. In order to understand the difference in biological stability between these two water treatment plants, AOC meaurement was conducted. The goals of this study were: (1) to understand the water purification process of advanced and traditional water treatment plants, and to understand the concentration in AOC fluctuation in their water distribution networks; (2) to learn about differences in how the two water treatment plants remove AOC, and to know where is improvement ; (3) to use program analysis to produce a simple formula and AOC-related water quality parameters for the two water treatment plants, providing AOC control and management strategies in the future. The results concluded that the raw water of the two water treatment plants was primarily a hybrid of hydrophobic and hydrophilic molecules, and the highest values of AOC were found in winter. The CCLWTP had an overall removal rate of 54 %, and the GYWTP had an overall removal rate of 36 %. The CCLWTP conformed to the additions of an advanced water purification unit, but the water treatment process was relatively complex. Its AOC concentration varied considerably during the course of the water treatment process, while that of the GYWTP showed more stable measurements. The CCLWTP used coagulation precipitation, rapid filtration, and biological activated carbon filtration to effectively remove the AOC. The coagulation precipitation unit used by the GYWTP was most effective process in the removal of AOC and rapid filtering was less effective one. The treated water of CCLWTP maintained an AOC concentration under 51 £gg acetate-C/L in its water distribution network, while the treated water of GYWTP mostly kept a concentration of AOC lower than 71 £gg acetate-C/L. Although the CCLWTP water pipe network had lower AOC values, it demonstrated unstable changes in levels of AOC concentration. This shows that oxidation and disinfectants in the water treatment process cannot successfully oxidize all organic matter into AOC. In contrast, the GYWTP showed a more stable removal in AOC content. For the artificial neural network system simulation, the simulation values of CCLWTP water treatment process and water distribution network are correlated less closely with the measured actual value than those of the GYWTP do. This is found to be mostly due to the relatively large fluctuations in AOC in the CCLWTP. The AOC values in the CCLWTP water treatment process and water distribution network are highly correlated to TOC, TDS, and NH3-N. For the GYWTP, AOC values were mostly correlated to TOC, temperature, and NH3-N. Finally, the two common factors for water quality at both water plants were TOC and NH3-N, we recommend that these two items can be taken into consideration to control and manage AOC in water treatment.

Because of high intense population is in Taiwan, households water use requires a considerable amount. It is substantially reduce daily water use to share primary water resources, if we can reclaim domestic wastewater properly and make it support. Currently, reclaiming water is an emerging requirement for management and application. If we can adequately monitor and treat reclaimed water, reducing environmental contaminants, costs, and environmental feedback is possible. The study treated domestic wastewater of Feng-Shan river using GAC trickling filter with two column in a series and the removal efficiency of organic carbon was observed. The experimental results indicated that removal efficiency of organic carbon concentration was decreased as the empty-bed contact time (EBCT) increased. The best average removal efficiency of TOC and DOC was about 72% and 78%. According to the TOC removal rates using GAC at different temperatures, the TOC removal rates at room temperature and 4¢Jwere respectively 95% and 90% in the first column of the experiment and 85% and 80% in the second column. The removal rates of dissolved organic carbon (DOC) using GAC folter system at room temperature and 4¢J were respectively 95% and 90% in the first column of the experiment and 90% and 87% in the second column. Obviously,the TOC removal rate treated using GAC filter system at room temperature was superior to that treated at 4¢J In comparing treated water and recycled water,most of the water quality parameters (temperature¡BSuspended solids¡BBOD¡BCOD¡BpH) were to meet recycled water quality standards.However, the system due to use GAC trickling filter system treatment that easily decrease dissolved oxygen in treated water but conductivity in treated water without changes. These two water parameters were failed to meet the recycled water standards. By the way, we found trained GAC through SEM irradiation the biofilm area of trained GAC surface at 25¢Jwas superior to that treated at 4¢J. It corresponds to the removal efficiency of organic carbon, the removal efficiency of 25¢J was higher than result of 4¢J. Therefore, a certain relationship between the biofilm area and removal efficiency of organic carbon is existed in this work.

Carters Creek in Brazos County, Texas, like many surface water reaches in the Texas Gulf Coast region, has been identified for bacteria and nutrient impairment on the Texas Commission on Environmental Quality (TCEQ) 303(d) List. Carters Creek drains a rapidly urbanizing watershed and has been found to carry high concentrations of dissolved organic carbon (DOC), nitrate, phosphate and sodium. These constituents have a severe impact on the creek?s capacity for healthy aquatic life and increase the potential for eutrophication downstream. The creek has also had chronic high Escherichia coli counts, making the creek unsuitable for contact recreation according to the accepted standard for surface water quality, which is a geometric mean of 126 CFU per 100 ml. In this study, grab samples were taken twice monthly from fifteen sites on Carters Creek and its subcatchments from July 2007 to June 2008. The samples were analyzed for E. coli, DOC, total N, NO3-N, NH4-N, Na+, K+, Mg2+, Ca2+, F-, Cl-, Br-, NO2-, SO42- and PO4-3. Mean annual DOC concentrations varied from 24.8 mg/L in Carter at Boonville Road to 55.5 mg/L in Wolfpen Creek; sodium varied from 33 mg/L in Carter at Old Reliance Road to 200 mg/L, also in Wolfpen Creek. Burton 4, the subcatchment with the highest geometric mean for E. coli with 2547 CFU/100 mL, was also sampled with greater geographical intensity for E. coli and optical brightener fluorescence at 445 nm to identify any leaking sewer pipes, but no evidence of defective pipes was found. During both the spring season and annual high flow (storm events), E. coli counts were positively correlated with total urban land use, probably caused by storm runoff carrying residues from impervious surfaces into the stream. High flow E. coli also had a negative relationship with potassium and a positive relationship with calcium, possibly suggesting a bioflocculation effect. Sites downstream of wastewater treatment plants (WWTPs) showed higher nitrate, phosphate, sodium, potassium, chloride and fluoride than other urban subcatchments. Creeks with golf courses carried more phosphate, sodium and fluoride than subcatchments without golf courses or WWTPs.