MICROBIOLOGICAL STUDY ON THE METHANE PRODUCTION IN MARINE

与大多数细菌不同，产甲烷细菌的膜脂是由特殊的乙醚连接的甘油脂组成的。因此，可以通过测定海洋沉积物中的脂肪成分来估计海洋产甲烷细菌的生物量和活性。东京湾、Aburatsubo Inlet和Suruga湾最内侧的近岸富营养化沉积物中，间隙水样中甲烷浓度为0.12-93nmol/g，脂肪浓度为17-152 ng/g，这些值在每个沉积物中密切相关。对这些沉积物样品的培养实验表明，沉积物中存在几类产甲烷细菌，如利用醋酸盐、氢气+二氧化碳气体和甲醇等。它们的活性远高于从近海沉积物中获得的致病菌。在Sagami和Suruga Bays等近海沉积物中，间隙水甲烷浓度为0.32-0.65nmol/g，脂肪浓度为4.6-21 ng/g，培养实验中观察到甲醇利用率远低于富营养化沉积物。研究了常见浮游动物如桡足类和真甲藻等肠道微生物的产甲烷活性。测得30份真甲藻粪球的产甲烷活性为1.8微摩尔/粒。在另一个实验中，在60天的培养中产生了615微摩尔/克的甲烷。微生物区系为利用甲醇的微生物区系。

Membrane lipids of methanogenic bacteria are composed of special ether-linked glycerelipids, different from most of bacteria. So it is possible to estimate biomass of marine methanogenic bacteria and their activity by determining the lipid components in marine sediments. In the coastal eutrophicated sediments, such as Tokyo Bay, Aburatsubo Inlet and inner most part of Suruga Bay, methane concentrations were observed 0.12-93 nmol/g in the interstitial water samples, and lipid concentrations were 17-152 ng/g. These values were closely related in each sediment. Incubation experiments with these sediment samples showed that there are several groups of methanogenic bacteria in the sediments, such as utilizers of acetate, hydrogen+carbon dixide gasses, and methanol. Their activities were much higher than the mrethanogens obtained from off shore sediments. In the sediments of off shore waters like Sagami and Suruga Bays, methane concentrations were 0.32-0.65 nmol/g in the interstitial waters, and lipid concentrations were 4.6-21 ng/g. It was observed in the incubation experiments that methanol utilizers were much lower compared with eutrophicated sediments. Methanogenic activities of the intestinal micro flora of common zooplankton like copepods and euphausia were studies. Methanogenic activities were observed to be 1.8 micro mole per fecal pellets of 30 specimens of euphausia. In another experiment 615micro mols/g of methane were produced during 60 days of incubation. The microflora were observed to be methanol utilizers.