In situ fluorescence measurements in coastal waters

Blue fluorescence of seawater resulting from ultraviolet excitation has been used to study various aspects of the marine carbon cycle. The optical properties of dissolved organic matter affect ocean color and control the quantity and quality of sunlight that penetrates seawater. While most fluorescence measurements involve discrete sampling, this paper presents some instrumental developments that allow real-time in situ measurements with high temporal and spatial resolution in coastal waters. Fluorescence is used to study benthic fluxes of organic compounds, to estimate fluxes of dissolved organic matter (DOM) off continental margins, and to identify sources and sinks of DOM in coastal waters.