title: Optical microsensors for analysis of microbial communities.
abstract: Fiber-optic microprobes connected to sensitive light meters are ideal tools to resolve the steep gradients of light intensity and spectral composition that prevail in aggregates and surface-associated microbial communities in sediments, biofilms, and microbial mats. They allow for a detailed mapping of light fields and enable insights to the complex optical properties of such highly light-scattering and -absorbing microbial systems. Used in combination with microsensors for chemical species, fiber-optic irradiance microprobes allow for detailed studies of photosynthesis regulation and of the photobiology of microbial phototrophs in intact samples under ambient microenvironmental conditions of the natural habitat. Fiber-optic microprobes connected to sensitive fluorometers enable microscale fluorescence measurements, which can be used to map (i) diffusivity and flow; (ii) distribution of photosynthetic microbes, via their photopigment autofluorescence; and (iii) activity of oxygenic photosynthesis via variable chlorophyll fluorescence measurements. Furthermore, by immobilizing optical indicator dyes on the end of optical fibers, fiber-optic microsensors for temperature, salinity, and chemical species such as oxygen, pH, and CO2 can be realized.
authors.affiliation: Marine Biological Laboratory, Institute of Biology, University of Copenhagen, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Kühl
mesh_terms: D018441:Biofilms; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D004058:Diffusion; D004783:Environmental Microbiology; D005336:Fiber Optic Technology / Q000295:instrumentation; D005453:Fluorescence; D005470:Fluorometry; D019015:Geologic Sediments / Q000382:microbiology; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000032:analysis; D049449:Luminescence; D008832:Microchemistry / Q000295:instrumentation; D055100:Optical Fibers; D010788:Photosynthesis; D012212:Rheology / Q000295:instrumentation; D012542:Scattering, Radiation; D013499:Surface Properties
chemical_list: D045342:Light-Harvesting Protein Complexes