Bio-optical Characteristics and the Vertical Distribution of Photosynthetic Pigments and Photosynthesis in an Artificial Cyanobacterial Mat.

摘要: Zonations of photosynthesis and photopigments in artificial cyanobacterial mats were studied with (i) oxygen pH microsensors, (ii) fiber-optic microprobes for field radiance, scalar irradiance, PSII fluorescence, (iii) a light microscope equipped spectrometer spectral absorbance fluorescence measurements. Our analysis revealed the presence several distinct 1–2 mm thick layers mixed patches anoxygenic photosynthetic bacteria. Strong attenuation visible confined euphotic zone to uppermost 3 mat, where levels 3–4 times air saturation peak up 8.8 observed under saturating irradiance (413 μmol photon m−2 s−1). Oxygen penetration was 5 decreased 1 darkness. Volumetric consumption photic aphotic zones illuminated mat 5.5 2.9 higher, respectively, than dark incubated mats. Scalar reached 100–150% incident upper 0.5 due intense scattering matrix cells, exopolymers, carbonate precipitates. In deeper nearly exponentially, highest coefficients 6–7 mm−1 found layers, photopigment also peaked. Visible attenuated >100 more strongly near infrared light. Microscope spectrometry on thin sections allowed detailed measurements at defined positions relative surface. Besides strong signals (Chl phycobiliproteins), both green purple bacteria evident from Bchl c. Microprofiles correlated well microdistributions phototrophs determined an accompanying study.