Photosynthesis oxygen and

Redox intensity or electron activity in natural waters is usually determined by the balance between those processes which introduce oxygen (e.g. dissolution of atmospheric oxygen, photosynthesis) and those which remove oxygen (e.g. microbial decomposition of organic matter). Often these processes are controlled by the availability of inorganic nutrients such as phosphate and nitrate, e.g. as utilized in the formation of organic matter during photosynthesis (see Section 3.3.4). 

Paerl, H. W., Bebout, B. M., and Pmfert, L. E. (1988). Naturally-occurring patterns of oxygenic photosynthesis and N2 fixation in a marine microbial mat physiological and ecological ramifications. In Proc. 2nd Ind. Symp. on Microbial Mats. ASM Publications, Rosenberg/Edat, Israel, pp. 326—341. 

As will be discussed below, respiration requires electron acceptors, and many of the lithotrophic modes of metabolism require oxygen, making many believe that they were rather late metabolic inventions, occurring only after the world was oxic, or at least after oxygen respiration was invented. This is not necessarily the case, for a variety of reasons first, the invention of oxygenic photosynthesis, and the resulting... 

The overall consequence of the co-evolution of oxygenic photosynthesis and the redox state of the ocean is a relatively well-defined trace-element composition of the bulk phytoplankton. Analogous to Redfield s relationship between the macronutrients, trace-element analyses of phytoplankton reveals a relation for trace elements normahzed to cell phosphorus of (C125N16P1S13... 

Bebout B. M., Paerl H. W., Crocker H. W., and Prufert L. E. (1987) Diel interactions of oxygenic photosynthesis and N2 fixation (acetylene reduction) in a marine microbial mat community. A/7/7/. Environ. Microbiol. 53, 2353-2362. 

Since the Precambrian, oxygenic photosynthesis and aerobic respiration have been the dominant reactions in the cycling of organic carbon (Des Marais et al., 1992) (see Section 8.09.5). The production of organic matter by oxygenic photosynthesis can be illustrated by the production of glucose ... 

Gloeobacter violaceus is a unicellular cyanobacteria that besides the outer wall layer only has one membrane the cell membrane. It performs oxygenic photosynthesis and the photosynthetic complexes are localised in the cell membrane (Rippka et al, 1974). Long phycobilisomes are oriented perpendicular to the cell membrane and the phycobiliproteins carry phycoerythrobilin, phycourobilin, phycocyanin and allophycocyanin (Guglielmi et al, 1981, Bryant era/., 1981)... 

Note that the presence of biogenic gases such as O2/O3 + CH4 may imply the presence of an active biosphere, but their absence does not imply the absence of life. Life existed on Earth before the interplay between oxygenic photosynthesis and carbon cycling produced an oxygen-rich atmosphere (see 5.6). 

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