Mixotrophic dinoflagellates are photosynthetically active, but are also heterotrophic. Further research has explored reflectance of ultraviolet and photosynthetically active radiation. The main source of photosynthetically derived energy is phytoplankton. Cyanobacteria are also photosynthetically active and can therefore meet carbon requirements independently. Plants within the genus "Cuscuta" generally do not contain chlorophyll, nor are they photosynthetically active. Photographic estimation of photosynthetically active radiation&colon; evaluation of a computerized technique. Mounds receive the highest amount of photosynthetically active radiation (PAR) and pits the lowest amount. Quite apart from its effect on temperature, incident radiation is also important photosynthetically. Salt marshes are quite photosynthetically active and are extremely productive habitats. This also results in lowered "photorespiration" due to less photosynthetically generated oxygen. He concluded that the most photosynthetically active regions will have the highest concentrations of bacteria. It is red-pigmented, not being photosynthetically active. Photosynthetically fixed carbon in terrestrial plants is depleted in C compared to atmospheric CO. This range is called "Photosynthetically Active Radiation (PAR)".