Polerecky Lubos, Bachar Ami, Schoon Raphaela, Grinstein Mor, Jørgensen Bo Barker, de Beer Dirk, Jonkers Henk M
Max-Planck-Institute for Marine Microbiology, Celsiusstrasse 1, DE-28359 Bremen, Germany.
Environ Microbiol. 2007 Aug;9(8):2007-24. doi: 10.1111/j.1462-2920.2007.01317.x.
In dense stratified systems such as microbial mats, photosynthesis and respiration are coupled due to a tight spatial overlap between oxygen-producing and -consuming microorganisms. We combined microsensors and a membrane inlet mass spectrometer with two independent light sources emitting in the visible (VIS) and near infrared (NIR) regions to study this coupling in more detail. Using this novel approach, we separately quantified the activity of the major players in the oxygen cycle in a hypersaline microbial mat: gross photosynthesis of cyanobacteria, NIR light-dependent respiration of Chloroflexus-like bacteria (CLB) and respiration of aerobic heterotrophs. Illumination by VIS light induced oxygen production in the top approximately 1 mm of the mat. In this zone CLB were found responsible for all respiration, while the contribution of the aerobic heterotrophs was negligible. Additional illumination of the mat with saturating NIR light completely switched off CLB respiration, resulting in zero respiration in the photosynthetically active zone. We demonstrate that microsensor-based quantification of gross and net photosyntheses in dense stratified systems should carefully consider the NIR light-dependent behaviour of CLB and other anoxygenic phototrophic groups.
在诸如微生物席这样的致密分层系统中，由于产氧微生物和耗氧微生物在空间上紧密重叠，光合作用和呼吸作用相互耦合。我们将微传感器和膜进样质谱仪与两个分别在可见光（VIS）和近红外（NIR）区域发光的独立光源相结合，以更详细地研究这种耦合关系。使用这种新方法，我们分别量化了高盐度微生物席中氧循环主要参与者的活性：蓝细菌的总光合作用、类绿弯菌属细菌（CLB）的近红外光依赖呼吸作用以及好氧异养菌的呼吸作用。可见光照射在微生物席顶部约1毫米处诱导产生氧气。在这个区域，发现CLB负责所有呼吸作用，而好氧异养菌的贡献可以忽略不计。用饱和近红外光对微生物席进行额外照射完全关闭了CLB的呼吸作用，导致光合活性区域的呼吸作用为零。我们证明，在致密分层系统中，基于微传感器对总光合作用和净光合作用的量化应仔细考虑CLB和其他无氧光合营养菌群的近红外光依赖行为。
