On a clear June day in 1975, Bob Buchanan and two Oslo colleagues pulled up water samples from a lake in Norway, examining the microorganisms growing at various depths. “When we got to 6 meters,” Buchanan recalls, “there was a band ofChlorobiumgrowing,” referring to a genus of green bacteria (now calledChlorobaculum) that belongs to a unique class of organisms called photolithotrophs. These bacteria require sunlight for photosynthesis but obtain cellular reductants from sulfur compounds rather than water. The bacteria buck the traditional chemical pathways for energy production and carbon fixation and instead use pathways discovered by Buchanan, a member of the National Academy of Sciences and emeritus professor at the University of California, Berkeley.

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Bob B. Buchanan的个人资料

1975年6月的一个晴天，鲍勃·布坎南（Bob Buchanan）和两位奥斯陆同事从挪威一个湖中抽取了水样，检查了各种深度生长的微生物。布坎南回忆说：“当我们到达6米时，就出现了一条成排的绿球藻，”这是指一种绿色细菌（现在称为绿藻）属，属于一类独特的生物，称为光生物。这些细菌需要阳光来进行光合作用，但会从硫化合物而不是水获得细胞还原剂。这种细菌打破了传统的化学途径来产生能量和固碳，而是利用了布坎南发现的途径，布坎南是美国国家科学院院士，加州大学伯克利分校的名誉教授。