Direct Determination of Carbon and Nitrogen Contents of Natural Bacterial Assemblages in Marine Environments

作者：Rumi Fukuda, Hiroshi Ogawa, Toshi Nagata, Isao Koike · 发表于：Applied and Environmental Microbiology · 年份：1998 · DOI：10.1128/aem.64.9.3352-3358.1998 · 被引用次数：635 · 研究领域：Microbial Community Ecology and Physiology、Marine and coastal ecosystems、Methane Hydrates and Related Phenomena

In order to better estimate bacterial biomass in marine environments, we developed a novel technique for direct measurement of carbon and nitrogen contents of natural bacterial assemblages. Bacterial cells were separated from phytoplankton and detritus with glass fiber and membrane filters (pore size, 0.8 &mgr;m) and then concentrated by tangential flow filtration. The concentrate was used for the determination of amounts of organic carbon and nitrogen by a high-temperature catalytic oxidation method, and after it was stained with 4',6-diamidino-2-phenylindole, cell abundance was determined by epifluorescence microscopy. We found that the average contents of carbon and nitrogen for oceanic bacterial assemblages were 12.4 +/- 6.3 and 2.1 +/- 1.1 fg cell-1 (mean +/- standard deviation; n = 6), respectively. Corresponding values for coastal bacterial assemblages were 30.2 +/- 12.3 fg of C cell-1 and 5.8 +/- 1.5 fg of N cell-1 (n = 5), significantly higher than those for oceanic bacteria (two-tailed Student's t test; P < 0.03). There was no significant difference (P > 0.2) in the bacterial C:N ratio (atom atom-1) between oceanic (6.8 +/- 1.2) and coastal (5.9 +/- 1.1) assemblages. Our estimates support the previous proposition that bacteria contribute substantially to total biomass in marine environments, but they also suggest that the use of a single conversion factor for diverse marine environments can lead to large errors in assessing the role of bacteria in food webs and biog...