Abstract:

Of all the biochemical inventions in the history of life, photosynthesis is surely one of the grandest, since the production of oxygen as a waste product resulted from the photosynthesis also profoundly changed the composition of the worlds oceans, continents and atmosphere. However, the definitive evidence of the origin and evolution of photosynthesis such as the essential biological process, i.e. the nature of the earliest photosynthetic organisms as well as the problem dealing with how photosynthetic organisms obtain their photosynthetic apparatus and so on, may be lost forever. Thus, studies on the origin and evolution of photosynthesis became an important and enchanting scientific theme.Stromatolites may be Earth’s oldest macroscopic fossils; however, it remains controversy what, if any, biological processes are recorded in their morphology.Interestingly and enchantingly, two aspects of innovating cognitions have been obtained from the study on the biological process of stromatolites: (1)a qualitative similarity between conical stromatolites and some modern microbial mats suggests a photosynthetic origin for ancient stromatolites; (2) conical stromatolites are thought to be robust indicators of the presence of photosynthetic microbes in aquatic environments as early as 3 .5 billion years ago, and the cyanobacterial production of oxygen in the tips of modern conical aggregates implies not only that cyanobacteria built conical stromatolites but also that oxygen bubbles resulted from the photosynthesis may constrain the timing of the evolution of oxygenic photosynthesis. Therefore, many innovating cognitions obtained from studies on the morphological nature and its photosynthetic signals of the conical stromatolite, not only delegate an important advancement on the study of stromatolites but also become a typical paradigm to interpret the biological process from sedimentological feature. Ultimately,it is meaningful to trace this aspect of studies for the further understanding of both the sedimentological feature and the biological nature of stromatolites.

Key words: photosynthetic signal, morphological nature, conical stromatolite, research advancement