Microbial Communities in the Chemocline of a Hypersaline Deep-Sea Basin (Urania Basin, Mediterranean Sea)
Microbial Communities in the Chemocline of a Hypersaline Deep-Sea Basin (Urania Basin, Mediterranean Sea)
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高盐深海盆地（地中海乌拉尼亚盆地）化学跃层中的微生物群落
DOI：
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发表时间：
2001
影响因子：
4.4
通讯作者：
J. Overmann
中科院分区：
文献类型：
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作者：
A. Sass;H. Sass;M. Coolen;H. Cypionka;J. Overmann
乌拉尼亚盆地是地中海东部海底的一个高盐度硫化物卤水湖。由于该盆地位于海平面以下3,500米的深度，它只接受少量的浮游植物有机碳。在本研究中，细菌组合之间的界面上的高盐卤水和上覆海水进行了调查。硫化物浓度从0增加到10毫米内的垂直间隔为5米的界面。在这一化学跃层内，细菌细胞总数和胞外酶活性升高。采用11种培养方法，共分离出70株细菌。16 S核糖体DNA序列的32株是相同的环境序列中检测到的化跃层的培养独立的分子方法。这些菌株被鉴定为黄细菌、Alteromonas macleodii和Halomonasaquamarina。所有70株菌都能在好氧条件下生长。66株生长蛋白胨，酪蛋白水解产物和酵母提取物，而只有15株不利用聚合碳水化合物。其中21个菌株既能化能有机营养生长，又能化能无机营养生长。虽然在大多数情况下最可能的数量范围在总细胞计数的0.006至4.3%之间，但在含有氨基酸作为碳源和能源的培养基中，在趋化曲线以上确定了一个异常高的值54%。我们的研究结果表明，在乌拉尼亚盆地缺氧-缺氧界面繁衍生息的可培养细菌与其他化跃层栖息地典型的化能无机自养细菌有很大不同。
ABSTRACT The Urania basin is a hypersaline sulfidic brine lake at the bottom of the eastern Mediterranean Sea. Since this basin is located at a depth of ∼3,500 m below the sea surface, it receives only a small amount of phytoplankton organic carbon. In the present study, the bacterial assemblages at the interface between the hypersaline brine and the overlaying seawater were investigated. The sulfide concentration increased from 0 to 10 mM within a vertical interval of 5 m across the interface. Within this chemocline, the total bacterial cell counts and the exoenzyme activities were elevated. Employing 11 cultivation methods, we isolated a total of 70 bacterial strains. The 16S ribosomal DNA sequences of 32 of the strains were identical to environmental sequences detected in the chemocline by culture-independent molecular methods. These strains were identified as flavobacteria, Alteromonas macleodii, and Halomonas aquamarina. All 70 strains could grow chemoorganoheterotrophically under oxic conditions. Sixty-six strains grew on peptone, casein hydrolysate, and yeast extract, whereas only 15 strains did not utilize polymeric carbohydrates. Twenty-one of the isolates could grow both chemoorganotrophically and chemolithotrophically. While the most probable numbers in most cases ranged between 0.006 and 4.3% of the total cell counts, an unsually high value of 54% was determined above the chemocline with media containing amino acids as the carbon and energy source. Our results indicate that culturable bacteria thriving at the oxic-anoxic interface of the Urania basin differ considerably from the chemolithoautotrophic bacteria typical of other chemocline habitats.