Beyond the traditional threats, coral reefs are at risk of damage from land-based microbes finds a new study published in the journal Applied and Environmental Microbiology.
Scientists at University of Minnesota, Duluth, speculate that coral reefs are undergoing further damage from invading bacteria and fungi coming from land-based sources, such as outfall from sewage treatment plants and coastal inlets. The study raised the possibility that microbes from these sources are invading reefs off of the southeastern coast of Florida.
For the study scientists took water samples from coastal inlets, and from oceanic outfall effluent from water treatment plants along Florida’s southeastern coast, as well as from water and coral tissues in reefs. They found presence of some bacterial species and fungal families both in the land-based sources and in water and tissues within the coral reefs.
To identify and quantify the bacteria and fungi in the samples collected, scientists used techniques called “high throughput next generation DNA sequencing” and post that analysis, they used a software called SourceTracker “to evaluate and quantify the potential contributions from each of the land-based sources to the reef”.
Authors have a certain degree of confidence that because previous studies have failed to find on other reefs the microbes that appear both on nearby land and on reefs in this study, it means that those microbes have invaded these reefs. The data strongly indicates anthropogenic input sources are becoming established on reefs.
Scientists point out that assuming the hypothetical invaders actually are invaders, these microbes will have almost certainly changed the community structure of the reef microbiome, which could have damaging effect because the microbiome “plays various roles in nutrient cycling, coral health, and creating a habitat that is conducive to the various animals and plants that live in the reef”.