|This shows invading bacteria-algae (yellow arrows) in the Devonian reef-building corals. – ©Science China Press|
The coral-stromatoporoid reef disappearing from the planet earth was one of the most significant and representative phenomena for the Late Devonian F-F transitional mass extinction event. Professor GONG Yiming and his group (Wu Yibu, Feng Qi etc.) from State Key Laboratory of Biogeology and Environmental Geology of China University of Geosciences are trying to tackle this problem. After several years of continuous research, they have discovered that blooming and invading of bacteria and algae played an important role for before 370 Ma (Late Devonian F-F transition) coral-stromatoporoid reef disappearing from the planet earth. And this may be the key that unlock mystery of the modern reef-building coral bleaching. Their work, entitled “blooming of bacteria and algae is a biokiller for mass-extinction of Devonian coral-stromatoporoid reef ecosystems”, was published in SCIENCE CHINA Earth Sciences, 2013, Vol. 56, No.7.
Modern coral reefs are widespread in tropical and subtropical shallow sea, while coral-stromatoporoid reefs were much more widespread and spectacular before 370 Ma. But the former keep reducing because of reef-building corals bleaching; while the latter were extincted before 370 Ma. Why these happened? Are there any relationships between them? Bacteria and algae may be the most potent killer for both of them.
The innovation of this study is that evidences of direct interactions between bacteria and algae and living reef-building coral-stromatoporoids in the Devonian fossil records have been found in terms of the relationships between organisms and environments, as well as interactions between microbes and macro-organisms. These evidences include many kinds of invading bacteria and algae in “living” Devonian reef-builders in thin sections (as shown in the Figure 1). Bacteria and algae prevented growth of coral-stromatoporoids and the latter had the ability of self-healing(as shown in the Figure 2). Hence they suggested that blooming and invading of bacteria and algae was a possible biokiller for before 370 Ma coral-stromatoporoid reef disappearing from the planet earth. It is worth noting that similar phenomena have been widely reported in modern coral reefs.
This study may give the key to unlock mystery of the modern reef-building coral bleaching and also provide a warning and revelation in prevention and treatment of modern coral reef bleaching.