Next generation Advanced Laser Fluorometry (ALF) for characterization of natural aquatic environments: new instruments.

The new optical design allows single- or multi-wavelength excitation of laser-stimulated emission (LSE), provides optimized LSE optical collection for spectral and temporal analyses, and incorporates swappable modules for flow-through and small-volume sample measurements. The basic instrument configuration uses 510 nm laser excitation for assessments of chlorophyll-a, phycobiliprotein pigments, variable fluorescence (F(v)/F(m)) and chromophoric dissolved organic matter (CDOM) in CDOM-rich waters. The three-laser instrument configuration (375, 405, and 510 nm excitation) provides additional Fv/Fm measurements with 405 nm excitation, CDOM assessments in a broad concentration range, and potential for spectral discrimination between oil and CDOM fluorescence. The new measurement protocols, analytical algorithms and examples of laboratory and field measurements are discussed.