| Popis: |
Data have been collected on the abundance of obligately aerobic, bacteriochlorophyll-a-containing bacteria in a marine microbial mat on the West Frisian Island of Texel, The Netherlands. Plate counts on media rich in organic matter revealed average numbers of 3∗105·cm−3 sediment in the top 10 mm of the mat; the number of purple non-sulphur bacteria was of the same magnitude. Due to the relatively small dimensions of obligately aerobic anoxygenic phototrophic bacteria and purple non-sulphur bacteria, compared to those of purple sulphur bacteria, the contributions of either of the two former groups to the biomass of Bchl-a-containing organisms was approximately 3%. The specific Bchl-a-content of the isolated obligately aerobic phototrophs was very low (0.8 to 1.0 μg·mg−1 protein) compared to that of purple non-sulphur bacteria (16 to 20 μg·mg−1 protein), and purple sulphur bacteria (27 to 30 μg·mg−1). As a consequence, the relative contribution to the total Bchl a concentration of the two former groups (0.1% and 2.1%, respectively) was negligible, compared to that of the purple sulphur bacteria (97.8%). Salinities 140. |
