Biogeochemical processes in the saline meromictic Lake Kaiike, Japan: implications from molecular isotopic evidences of photosynthetic pigments.
Biogeochemical processes in the saline meromictic Lake Kaiike, Japan: implications from molecular isotopic evidences of photosynthetic pigments.
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DOI：
10.1111/j.1462-2920.2005.00772.x
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发表时间：
2005-07
影响因子：
5.1
通讯作者：
N. Ohkouchi;Y. Nakajima;H. Okada;N. Ogawa;Hisami Suga;K. Oguri;H. Kitazato
中科院分区：
文献类型：
--
作者：
N. Ohkouchi;Y. Nakajima;H. Okada;N. Ogawa;Hisami Suga;K. Oguri;H. Kitazato
为研究自然环境中光合自养生物的种间地球化学过程，测定了从日本海池湖分离纯化的光合色素的碳、氮稳定同位素组成。在缺氧monimolimonion和底栖微生物垫，BChls e和isorenieratene相关的棕色菌株的绿色硫细菌的碳同位素组成基本上（约千分之10）耗尽（13）C相对于那些发现在化跃层。结合16 SrDNA证据，强有力地表明，褐黄水虱在缺氧的单池和底栖微生物垫中通过利用（13）C-贫化的再生CO（2）进行光合作用。相比之下，无论是Chl a和BChl a的monimolimonion和微生物垫有相似的同位素组成，因为他们在化跃层，这意味着源生物只生活在化跃层。在化跃层中，BChl e同系物的氮同位素组成为-7.7 ‰ ~-6.5 ‰，而BChl a同系物的氮同位素组成为-2.1 ‰。这些同位素组成表明，绿色硫细菌Chlorobium phaeovibrioides在化跃层中进行固氮，而紫色硫细菌Halochromatium sp.和蓝藻Synechococcus sp.可能同化亚硝酸盐。
Stable carbon and nitrogen isotopic compositions were determined for individual photosynthetic pigments isolated and purified from the saline meromictic Lake Kaiike, Japan, to investigate species-independent biogeochemical processes of photoautotrophs in the natural environment. In the anoxic monimolimnion and benthic microbial mats, the carbon isotopic compositions of BChls e and isorenieratene related to brown-coloured strains of green sulfur bacteria are substantially ( approximately 10 per thousand) depleted in (13)C relative to those found in the chemocline. In conjunction with 16S rDNA evidence reported previously, it strongly suggests that Pelodyctyon luteolum inhabited and photosynthesized in the anoxic monimolimnion and benthic microbial mats by using (13)C-depleted regenerated CO(2). By contrast, both Chl a and BChl a in the monimolimnion and microbial mats have similar isotopic compositions as they do in the chemocline, implying that the source organisms live only in the chemocline. In the chemocline, the nitrogen isotopic compositions of BChl e homologues ranges from -7.7 to-6.5 per thousand, whereas that of BChl a is -2.1 per thousand. These isotopic compositions suggest that green sulfur bacteria Chlorobium phaeovibrioides would conduct nitrogen fixation in the chemocline, whereas purple sulfur bacteria Halochromatium sp. and cyanobacteria Synechococcus sp. may assimilate nitrite.