Light environment and synthesis of bacteriochlorophyll by populations of Chromatium okenii under natural environmental conditions

Abstract

In the meromictic alpine Lake Cadagno a dense layer of phototrophic bacteria, mainly Chromatium okenii and Amoebobacter purpureus, develop annually at the chemocline at about 10 to 11 m depth. Radiometric spectral profiles of the incident sunlight demonstrate different attenuation coefficients in the mixolimnion and in the chemocline not only for the visible light effective at each depth (photosynthetically available radiation), but also for selected photosynthetically active wavelengths used by oxygenic and anoxygenic phototrophs. Ph Show more