Diseases are omnipresent in aquatic ecosystems but there are numerous signs that some parts of our oceans/freshwater systems are more affected. The number of disease outbreaks in marine organisms is increasing in several key groups of marine animals, which include marine mammals and corals, but other less well-studied organisms may be equally affected. Also unprecedented mass mortality and rapid disappearance of once-common species imply an unbalanced system or an introduced pathogen, or both. As causes for the outbreak of marine diseases strong environmental drivers are key, such as eutrophication (sewage and agricultural runoff) or rising global temperatures (climate change) but also pollution, invasion of new/exotic species, and destruction of coastal habitats can serve as stresses that interact in complex ways with the microbiota and their hosts. Diseases in some marine animals affect humans directly, for example through cultural or economic costs – others more indirectly through the degradation of ecosystem productivity.
Animals and plants form a distinct habitat for microbial communities (microbiomes), and these microbial associations are integral to life. Host-associated communities colonize every accessible host tissue, have an impact on host function and contribute to host fitness and health. There is accumulating evidence from studies that show links between diseases and the diversity of an organism’s microbiome. Disturbing the balance between the host and its colonizing microbiota appears to foster diseases. Vibrios are important bacterial pathogens for animals reared in aquaculture but are at the same time symbionts of several vertebrate and invertebrate hosts, such as fish, sea anemones, sponges, molluscs, and zooplankton.
The objective of the project was to gain a better understanding of how environmental stress affects the assembly of host-associated microbial communities and how these host-associated communities influence disease emergence.
