Bioavailability of dissolved organic carbon and fulvic acid from an Australian floodplain river and billabong

2007 ◽  
Vol 58 (2) ◽  
pp. 222 ◽  
Author(s):  
Suzanne McDonald ◽  
Jennifer M. Pringle ◽  
Paul D. Prenzler ◽  
Andrea G. Bishop ◽  
Kevin Robards
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Fulvic Acid ◽  
Heterotrophic Bacteria ◽  
Fulvic Acids ◽  
Lag Phase ◽  
Floodplain Ecosystems ◽  
Vital Resource ◽  
Number Of Bacteria

Dissolved organic carbon (DOC) is a vital resource for heterotrophic bacteria in aquatic ecosystems. The bioavailability of fulvic acid, which comprises the majority of aquatic DOC, is not well understood. The present study examined the bioavailability of bulk DOC and fulvic acid from two contrasting but inter-related water bodies: the Murrumbidgee River and adjacent Berry Jerry Lagoon. Bacteria utilised fulvic acids; however, bulk DOC was more bioavailable. Bacteria were able to utilise Murrumbidgee River DOC and fulvic acid more readily than Berry Jerry Lagoon DOC and fulvic acid, suggesting that the quality of carbon may be an important factor to consider when evaluating lateral exchange of nutrients between the main channel and floodplain. Chemical characteristics of fulvic acids appeared to explain some of the variation in fulvic acid bioavailability. The higher the molecular weight and complexity of the fulvic acid, the longer it took for bacteria to utilise the substrate (lag phase), but the larger the number of bacteria that grew on the substrate. The present study calls attention to the need for further multidisciplinary studies to address the quality of carbon in riverine-floodplain ecosystems.

Rate of Cd2+ Release from Dissolved Fulvic Acid and Natural Dissolved Organic Carbon as a Function of UVB Dose

2006 ◽  
Vol 3 (6) ◽  
pp. 433 ◽  
Author(s):  
R. Néron ◽  
J. C. Auclair ◽  
C. Fortin
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Fulvic Acid ◽  
Surface Waters ◽  
Iron Concentration ◽  
Fulvic Acids ◽  
Ion Concentration ◽  
Uvb Radiation ◽  
Free Ion ◽  
Uv Dose

Environmental Context. Atmospheric ozone depletion results in an increase of UVB radiation impinging on the surface waters of aquatic ecosystems. Radiative absorption by dissolved humic substances results in bleaching and photochemical decomposition to smaller molecular weight dissolved components. With respect to the lake biota, this can reduce the effectiveness of a natural absorptive protective UV screen, as well as enrich the surface waters with microbial substrates and previously bound biologically unavailable trace metals. In controlled experiments using low-level Cd-contaminated dissolved fulvic acids and natural lakewater dissolved organic carbon, we examine the relationship between increasing UV dose and cadmium free-ion (Cd2+) concentrations. Abstract. Using controlled UVB exposures in a laboratory incubator, the photolytic release of bound cadmium from cadmium-contaminated dissolved fulvic acid and cadmium-amended natural lakewater dissolved organic carbon was examined using an ion-exchange technique, developed to measure the cadmium free-ion concentration (Cd2+). In the fulvic acid experiments, with increasing UVB dose, the increasing cadmium free-ion concentration followed an exponential saturation function, whereas the decrease in dissolved organic carbon was linear. Experiments using natural lakewaters did not reveal any increase in Cd2+, even at high UVB exposures. Given the much greater dissolved iron concentration in humic natural lakewaters, relative to the fulvic acid medium, iron photoreduction and reoxidation produces fresh amorphous iron oxide surfaces. We hypothesize that these bind the cadmium free-ion, thus reducing its aqueous concentration. Depending on Cd2+ affinity to biological surfaces, this mechanism might thus competitively further protect the biota from trace metal toxicity.

Impact of Cyanobacterial Associate and Heterotrophic Bacteria on Dissolved Organic Carbon and Metal in Moss and Peat Leachate: Application to Permafrost Thaw in Aquatic Environments

2017 ◽  
Vol 23 (5-6) ◽  
pp. 331-358 ◽  
Author(s):  
Liudmila S. Shirokova ◽  
Joachim Labouret ◽  
Melissa Gurge ◽  
Emmanuelle Gérard ◽  
Irina S. Ivanova ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Heterotrophic Bacteria ◽  
Aquatic Environments ◽  
Permafrost Thaw

Humic Colloid Generation of Transuranic Elements in Groundwater and Their Migration Behaviour

1986 ◽  
Vol 84 ◽  
Author(s):  
J.I. Kim ◽  
G. Buckau ◽  
W. Zhuang
Keyword(s):  
Heavy Metal ◽  
Humic Acid ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Metal Ions ◽  
Fulvic Acid ◽  
Photoacoustic Spectroscopy ◽  
Heavy Metal Ions ◽  
Colloidal Form ◽  
Doc Concentration

AbstractThe generation of humic colloids of Am(III) has been investigated in Gorleben groundwaters containing different amounts of humic substances. Dissolved organic carbon (DOC) in these groundwaters consists mainly of humic acid and fulvic acid, which is present in a colloidal form through aggregation with trace heavy metal ions of groundwater constituents. Concentrations of these heavy metal ions are proportional to the DOC concentration. The generation of Am(III) pseudocolloids through geochemical interactions with humic colloids in different groundwaters is quantified by ultrafiltration as well as ultracentrifugation by the aid of radiometric concentration measurements. The speciation of dissolved Am(III) species in groundwaters is carried out by laser induced photoacoustic spectroscopy (LPAS).

Monitoring advanced oxidation of Suwannee River fulvic acid

2010 ◽  
Vol 7 (3) ◽  
pp. 225 ◽  
Author(s):  
Janey V. Camp ◽  
Dennis B. George ◽  
Martha J. M. Wells ◽  
Pedro E. Arce
Keyword(s):  
Organic Carbon ◽  
Fluorescence Spectroscopy ◽  
Fulvic Acid ◽  
Electrical Discharge ◽  
Fulvic Acids ◽  
Pilot Scale ◽  
Suwannee River ◽  
Suwannee River Fulvic Acid ◽  
Pulsed Electrical Discharge ◽  
By Products

Environmental context.Potentially toxic disinfection by-products form when water containing humic and fulvic acids is chlorinated to destroy pathogenic microorganisms. A pulsed electrical discharge was examined for its ability to destroy an aquatic fulvic acid by oxidation. Spectroscopically, changes in the organic structures were observed, but carbon content and disinfection by-products were not reduced. Abstract.A pilot-scale pulsed electrical discharge (PED) system was used to treat Suwannee River fulvic acid (SRFA) as a representative precursor material for the formation of disinfection by-products (DBPs), specifically trihalomethane compounds. Ultraviolet-visible and fluorescence spectroscopy, dissolved organic carbon (DOC), and the trihalomethane formation potential (THMFP) were used as analytical parameters to monitor the effects of treatment on the substrate. The potential for SRFA degradation (5 mg L–1 DOC) was examined over 60 min at each of four operational configurations, varying pulse energy and frequency (0.15 J and 60 Hz, 0.15 J and 120 Hz, 0.4 J and 60 Hz, and 0.4 J and 120 Hz) in a factorial design. Statistically significant changes occurred for UV254, EX254EM460, and EX328EM460 under selected conditions; however, concomitant changes in DOC and THMFP were not observed. The composition of SRFA changed, but organic carbon was not mineralised to carbon dioxide. In addition to showing degradation by PED, the significance of the preliminary findings of this research was to demonstrate that spectroscopic monitoring of precursor degradation alone can be misleading, and that whereas ultraviolet-visible and fluorescence spectroscopy indicated degradation of precursor compounds, DOC and THMFP measurements were unchanged and did not support the occurrence of mineralisation in this system.

scholarly journals High-frequency measurements explain quantity and quality of dissolved organic carbon mobilization in a headwater catchment

2019 ◽  
Vol 16 (22) ◽  
pp. 4497-4516 ◽  
Author(s):  
Benedikt J. Werner ◽  
Andreas Musolff ◽  
Oliver J. Lechtenfeld ◽  
Gerrit H. de Rooij ◽  
Marieke R. Oosterwoud ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
High Frequency ◽  
Riparian Zone ◽  
Quality Parameters ◽  
Riparian Zones ◽  
Frequency Measurements ◽  
Seasonal Scale ◽  
Headwater Catchment

Abstract. Increasing dissolved organic carbon (DOC) concentrations and exports from headwater catchments impact the quality of downstream waters and pose challenges to water supply. The importance of riparian zones for DOC export from catchments in humid, temperate climates has generally been acknowledged, but the hydrological controls and biogeochemical factors that govern mobilization of DOC from riparian zones remain elusive. A high-frequency dataset (15 min resolution for over 1 year) from a headwater catchment in the Harz Mountains (Germany) was analyzed for dominant patterns in DOC concentration (CDOC) and optical DOC quality parameters SUVA254 and S275−295 (spectral slope between 275 and 295 nm) on event and seasonal scales. Quality parameters and CDOC systematically changed with increasing fractions of high-frequency quick flow (Qhf) and antecedent hydroclimatic conditions, defined by the following metrics: aridity index (AI60) of the preceding 60 d and the quotient of mean temperature (T30) and mean discharge (Q30) of the preceding 30 d, which we refer to as discharge-normalized temperature (DNT30). Selected statistical multiple linear regression models for the complete time series (R2=0.72, 0.64 and 0.65 for CDOC, SUVA254 and S275−295, resp.) captured DOC dynamics based on event (Qhf and baseflow) and seasonal-scale predictors (AI60, DNT30). The relative importance of seasonal-scale predictors allowed for the separation of three hydroclimatic states (warm and dry, cold and wet, and intermediate). The specific DOC quality for each state indicates a shift in the activated source zones and highlights the importance of antecedent conditions and their impact on DOC accumulation and mobilization in the riparian zone. The warm and dry state results in high DOC concentrations during events and low concentrations between events and thus can be seen as mobilization limited, whereas the cold and wet state results in low concentration between and during events due to limited DOC accumulation in the riparian zone. The study demonstrates the considerable value of continuous high-frequency measurements of DOC quality and quantity and its (hydroclimatic) key controlling variables in quantitatively unraveling DOC mobilization in the riparian zone. These variables can be linked to DOC source activation by discharge events and the more seasonal control of DOC production in riparian soils.

scholarly journals Concentration of Total Organic Carbon and Its Fractions in Surface Water in Poland and Germany

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 35
Author(s):  
Patrycja Sobczak ◽  
Agata Rosińska
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Rhine River ◽  
Bacteriological Quality ◽  
Quality Of Water ◽  
Biodegradable Dissolved Organic Carbon

Total organic carbon (TOC) present in surface water consists of different fractions like dissolved organic carbon (DOC) or biodegradable dissolved organic carbon (BDOC). BDOC may have an impact on the bacteriological quality of water as it can be a source of carbon and energy for microorganisms. It is important to consider this parameter in case of the distribution of drinking water. The aim of this research was to compare the qualities of chosen surface water in Poland and Germany in terms of concentration of total organic carbon and its fractions. The samples were taken from the reservoir in Poland and Rhine River in Germany. The first one is a source of drinking water for humans. The research showed that, considering the analyzed compounds, the water from the river has better quality.

scholarly journals Bacterial enzymatic activity and bioavailability of heavy metals in sediments from Boa Viagem Beach (Guanabara Bay)

2003 ◽  
Vol 26 ◽  
pp. 60-68
Author(s):  
Mirian Crapez ◽  
José Antonio Baptista Neto ◽  
M. G. S. Bispo
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Organic Carbon ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Carbon Turnover ◽  
Guanabara Bay ◽  
Organic Matter Quality ◽  
Number Of Bacteria

This study focuses on the quality of the organic matter that reaches the sediment from Boa Viagem Beach and through the evaluation of the total bacterial count, the electron transport system activity (ETSA), the esterase activity (EST), as well as the protein and the organic matter contents. Seasonal variations of organic matter, protein content and the number of bacteria were particularly notable in the summer. ETSA reached a maximum of 7.48 µl O2 h-1 g-1 in the summer. EST activity presented a different pattern once it reached a maximum of 0.17 µg fluorescein h-1 g-1 in the winter. The temporal variation of ETSA and EST activity indicated that biopolymers predominated in the winter, and oligomers or monomers predominated in the summer. These results suggest that organic carbon turnover is more likely to be controlled by organic matter quality. The heavy metals concentrations, especially for Cu, Zn, Ni and Cr, indicated absence of the inhibition of dehydrogenase activity, and they are not bioavailable in the EC50 values

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