Image courtesy of yeowatzup via flickr
Call it the bacterial coup de grace: according to new research presented at the Society for General Microbiology's 162nd meeting, coral reefs weakened by the effects of global warming could be dying because of changes in their surrounding microflora. John Bythell, a biologist from Newcastle University, attributes many of the most recent mass coral deaths, such as the 1998 one in which 17% of the world's reefs perished, to slight variations in the microbes that live in and around them.As sea temperatures rise, Bythell explains that corals, already weakened by the loss of their zooxanthellae, become more prone to attack by pathogenic bacteria; at the same time, the symbiotic bacteria that live in the corals' guts and assist in their digestive process are weakened, enabling the harmful bacteria to multiply and wreak havoc on the corals. The corals' most effective defensive mechanism, a surface mucus that acts as a shield against pathogens, may also be inhibited by the combined impact of rising temperatures and the bacteria's assault.
What is lacking in current research efforts, Bythell and his colleagues argue, is a concerted effort by molecular biologists and reef scientists to study the causes of disease and bleaching in coral reefs. Future research could benefit from combining the separate disciplines' techniques and lead to new breakthroughs - and, hopefully, some hints as to how we may yet help rehabilitate an imperiled group of species.