Dissolved organic matter and nutrient dynamics of a coastal freshwater forested wetland in Winyah Bay, South Carolina

Chow, Alex T.; Dai, Jianing; Conner, William H.; Hitchcock, Daniel R.; Wang, Junjian

doi:10.1007/s10533-012-9750-z

Cited by 54 publications

(51 citation statements)

References 47 publications

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“…The cause of the seasonal shifts in the spectral slope ratio might be indicative of change in the dissolved matter origin, or due to different photochemical, biological or aggregation processes that are known to alter DOC MW and aromaticity (Floge and Wells, 2007;Helms et al, 2008). These findings as applied to the LD system could indicate the following: (1) Steep increases in spectral ratio associated with rain events bring in un-degraded organic material-compared with the ratios associated with older decomposed detrital matter of stagnant waters-as a fresh source of organic matter that provides a fresh carbon source (Chow et al, 2013). (2) The increase in rain-associated cloud cover causes a decrease in DOC photobleaching, the sunlight-induced conversion of larger, aromatic DOC molecules (larger spectral slope) into smaller MW molecules (smaller spectral slope), as demonstrated by Helms et al (2008).…”

Section: Discussionmentioning

confidence: 99%

Ecological succession among iron-oxidizing bacteria

et al. 2013

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Despite over 125 years of study, the factors that dictate species dominance in neutrophilic iron-oxidizing bacterial (FeOB) communities remain unknown. In a freshwater wetland, we documented a clear ecological succession coupled with niche separation between the helical stalk-forming Gallionellales (for example, Gallionella ferruginea) and tubular sheath-forming Leptothrix ochracea. Changes in the iron-seep community were documented using microscopy and cultivation-independent methods. Quantification of Fe-oxyhydroxide morphotypes by light microscopy was coupled with species-specific fluorescent in situ hybridization (FISH) probes using a protocol that minimized background fluorescence caused by the Fe-oxyhydroxides. Together with scanning electron microscopy, these techniques all indicated that Gallionellales dominated during early spring, with L. ochracea becoming more abundant for the remainder of the year. Analysis of tagged pyrosequencing reads of the small subunit ribosomal RNA gene (SSU rRNA) collected during seasonal progression supported a clear Gallionellales to L. ochracea transition, and community structure grouped according to observed dominant FeOB forms. Axis of redundancy analysis of physicochemical parameters collected from iron mats during the season, plotted with FeOB abundance, corroborated several field and microscopy-based observations and uncovered several unanticipated relationships. On the basis of these relationships, we conclude that the ecological niche of the stalk-forming Gallionellales is in waters with low organic carbon and steep redoxclines, and the sheath-forming L. ochracea is abundant in waters that contain high concentrations of complex organic carbon, high Fe and Mn content and gentle redoxclines. Finally, these findings identify a largely unexplored relationship between FeOB and organic carbon.

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Section: Discussionmentioning

confidence: 99%

Ecological succession among iron-oxidizing bacteria

et al. 2013

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“…24 Specifically, the pH and SC were measured using an Accumet XL60 dual channel pH/ion/conductivity meter. The DOC and TDN were determined by a Shimadzu TOC/TN analyzer (SM 5310B).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Wildfire Altering Terrestrial Precursors of Disinfection Byproducts in Forest Detritus

Wang

Dahlgren

Erşan

et al. 2015

Environ. Sci. Technol.

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Wildfire occurrence and intensity are increasing worldwide causing severe disturbances to forest watersheds used for potable water supply. The effects of wildfire on drinking water quality are not well understood, especially in terms of terrestrial dissolved organic matter (DOM) and DOM-associated formation of disinfection byproducts (DBP). As the forest floor layer is a major source of terrestrial DOM, we investigated characteristics and DBP formation of water extractable organic matter (WEOM) from the 0−5 cm depth of nonburned detritus (control) and burned detritus with black ash (moderate severity) and white ash (high severity) associated with the 2013 Rim Fire in California. Spectroscopic results suggested that the aromaticity of WEOM followed white ash > control > black ash and fluorescence region II (excitation 220−250 nm; emission 330−380 nm) of the emission-excitation-matrix was identified as a potential burn severity indicator. Compared to the control, WEOM from white and black ashes had lower reactivity in forming trihalomethanes (55%-of-control) and haloacetic acids (67%-of-control), but higher reactivity in forming the more carcinogenic haloacetonitrile after chlorination (244%-of-control) and N-nitrosodimethylamine after chloramination (229%-of-control). There was no change in reactivity for chloral hydrate formation, while WEOM from black ash showed a higher reactivity for haloketone formation (150%-of-control). Because wildfire consumed a large portion of organic matter from the detritus layer, there was lower water extractable organic carbon (27%-of-control) and organic nitrogen (19%-of-control) yields in ashes. Consequently, the wildfire caused an overall reduction in water extractable terrestrial DBP precursor yield from detritus materials.

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“…Timing and length of inundation periods can also be determinant in the concentration and chemical characteristics of dissolved nutrients (Chow et al, 2013). These serve as electron acceptors in the microbial degradation of organic matter and more specifically, the dissolved organic carbon (DOC) serve as substrate for methanogenic bacteria (Clymo et al, 1995;Chasar et al, 2000;Glatzel et al, 2004).…”

Section: Ch 4 Fluxes and Hydrologymentioning

confidence: 99%

“…November), could have been the result of an increase in DOC from cypress and some macrophytes fresh litter that usually peaks in late September and early October (Duever et al, 1984). For example, Chow et al (2013) found highest DOC inputs to be from litter fall in a coastal forested wetland in South Carolina, with its actual concentrations through the wet and dry seasons regulated mainly by hydrology. More research in the underlying biochemical processes involved in CH 4 emissions from these communities and its variation through the different inundation phases at a field scale is still needed.…”

Section: Ch 4 Fluxes and Hydrologymentioning

confidence: 99%