Scientists have begun to consider an organism as a sum of it’s parts, that is its associated microbes. Rather than the old view of all microbes being foes and definitively separate from the organism (host), it’s becoming more clear that most, if not close to all microbes, under ambient conditions are beneficial symbionts of the animal that can also be host- or tissue-specific. The human microbiome is a popular example of this, where associated bacterial community differences are correlated with location in or on the body (e.g. gut vs. skin on hand, even left vs. right hand) as well as ethnicity (e.g. specific enzymes and microbes help people of Japanese-origin digest seaweed).
There has been strong support for the human microbiome project and in parallel coral scientists have also focused more on the microbiome associated with corals, termed the coral holobiont. This emphasis has in large part been a response to better understand coral health and result of increasing disease occurrences. Much like in human health studies, research has highlighted that the coral holobiont is a complex metaorganism, which contains many more facets: archaea, bacteria, fungi, protists, viruses. The functions these players and their interactions with each are poorly understood. Today and yesterday’s lectures on coral health and immunity outlined some of the many victories, as well as large gaps that still remain. Over the last 70 years progress has been made in understanding the coral-animal as well as its health, however new sequencing tools are making it clear that we’ve only begun to scrape the surface of our understanding of these simple, yet complex and microbially-diverse organisms.
More on these advancements and gaps soon.