Publications

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1992
Chen, RF, Bada JL.  1992.  The Fluorescence of Dissolved Organic-Matter in Seawater. Marine Chemistry. 37:191-221.   10.1016/0304-4203(92)90078-o   AbstractWebsite

A total of 28 vertical profiles of seawater fluorescence was measured in the Sargasso Sea, the Straits of Florida, the Southern California Borderlands, and the central Pacific Ocean. In all cases, surface seawater fluorescence was low as a result of photochemical bleaching which occurs on the timescale of hours. Fluorescence of deep water was 2-2.5 times higher than that of surface waters, and was constant, implying a long residence time for fluorescent organic matter, possibly of the order of thousands of years. Fluorescence correlates well with nutrients (NO3-, PO43-) in mid-depth waters ( 100-1000 m) in the Sargasso Sea and the central North Pacific, consistent with results in the central Pacific and the coastal seas of Japan. This suggests that regeneration or formation of fluorescent materials accompanies the oxidation and remineralization of settling organic particles. The various sources and sinks of fluorescent organic matter in the global oceans are assessed. The major sources are particles and in situ formation; rivers, rain, diffusion from sediments, and release from organisms are minor sources. The major sink is photochemical bleaching.

1990
Chen, RF, Bada JL.  1990.  A Laser-Based Fluorometry System for Investigations of Seawater and Porewater Fluorescence. Marine Chemistry. 31:219-230.   10.1016/s0304-4203(05)80014-3   AbstractWebsite

A highly sensitive laser-induced fluorescence (LIF) system has been developed to study the fluorescence of dissolved organic carbon (DOC) in the marine environment. The LIF detector has a detection limit of approximately 10 attomoles (10x10(-18) moles) of pterin and eliminates internal quenching in highly fluorescent samples such as anoxic porewaters encountered when using conventional fluorometry. LIF analysis is rapid, reproducible, and uses only 100 mu-l of a sample. This small size requirement permits fluorescence analyses of samples often available only in limited amounts, such as pore-waters, hydrothermal vent waters, and rainwaters. In addition, the LIF detection system may greatly simplify extraction and separation procedures required to characterize the fluorescent components of DOC.