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Title: Characteristics of dissolved organic carbon revealed by ultraviolet/visible absorbance and fluorescence spectroscopy: The current status and future exploration

Author
item ZHANG, MINGCHU - University Of Alaska
item He, Zhongqi

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/18/2015
Publication Date: 10/2/2015
Citation: Zhang, M., He, Z. 2015. Characteristics of dissolved organic carbon revealed by ultraviolet/visible absorbance and fluorescence spectroscopy: The current status and future exploration. In: He, H, Wu, F., editors. Labile Organic Matter - Chemical Composition, Functions, and Significance in Soil and the Environment. SSSA Special Publication 62. Madison, WI:Soil Science Society of America. p. 1-22.

Interpretive Summary: Dissolved organic carbon (DOC) is an important research subject for various disciplines. The objectives of this chapter are to review and summarize recent advancement in ultraviolet/visible and fluorescence spectroscopic characterization of DOC and to identify the information gaps for future researches. Research efforts have been placed at least in four disciplinary areas for DOC: 1) impact of DOC on surface water (fresh and sea water) ecosystems; 2) treatment efficiency of sewage water treatment facilities or processes; 3) detecting trace DOC in drinking water, and 4) DOC and dissolved organic nitrogen (DON) in soil system as affected by management, and land use changes. Nevertheless, these research accomplishments are still far behind from providing a comprehensive understanding of the relationship between terrestrial land management practice and DOC in surface water. Further research in the DOC area will likely continue until a full understanding on agriculture soil management practice and its impact on surface water.

Technical Abstract: Dissolved organic carbon (DOC) is an important research subject for various disciplines. The objectives of this chapter are to review and summarize recent advancement in characterization of DOC by ultraviolet/visible (UV/Vis) and fluorescence spectroscopies and to identify the information gaps for future researches. The search for causes of rising DOC in rivers and lakes in Europe and North America has lead no exclusive conclusion, especially from DOC exported from arable land. More studies are still needed in this area. Most of UV/Vis and fluorescence methods developed in the past are still widely used in the current studies in the literature such as specific ultraviolet absorbance (SUVA), spectral slope for UV/Vis, and excitation and emission matrix (EEM) , fluorescence indexes (i.e. FI, Feff) for fluorescence spectroscopy. A few new methods are developed and tested such as ratio of tryptophan-like to fulvic/humic-like, self-organizing map and classification/regression tree for EEM data analysis, and UV spectral deconvolution. Nevertheless, these new methods are tested in limited sites and studies. Critics on current fluorescence methods can also be found in literature, such quenching agents in DOC solutions and interaction of DOC fluorophores. Future research should include standardizing test conditions (e .g. pH, ionic strength, ion composition) as such parameters would affect fluorescence yield of DOC. In addition, new data analysis methods should be developed and tested.