Rise of collagen-eating microbes may help explain gaps in the fossil record

Commenters focused on how collagen-eating microbes could affect the preservation of animal remains and help explain gaps in the fossil record. One commenter highlighted collagen’s unusual biology: hydroxyproline is made by modifying proline after protein synthesis, a process dependent on vitamin C, while bromine is needed to produce a modification found in collagen IV. Others drew broader implications, suggesting that enzymes capable of digesting collagen might illuminate collagen-related diseases, and that similar evolutionary changes could eventually enable microbes to break down plastics. The discussion also raised the possibility that overlooked nutritional requirements, such as bromine’s role as a trace element, could matter for long-term human spaceflight.

Several commenters compared collagen’s resistance to breakdown with lignin, whose early accumulation in plants has been proposed as one explanation for Carboniferous coal deposits. One commenter emphasized the theory that lignin-degrading fungi eventually changed that balance; another argued that coal’s exceptional abundance likely reflects both biological and geological conditions, including climate, productivity, and waterlogged basins. The exchange also distinguished bromine from iodine: commenters noted that bromide is commonly present in salt, whereas iodine deficiency has been widespread enough to prompt salt fortification. Together, the comments treated evolutionary innovations in decomposition as potentially important, while differing on whether a single biological change can explain major patterns in the geological record.