New research on seagrass microbiomes shows that bacteria living in seagrass roots help the plants survive toxic sediments and store carbon. The studies, covered by Resilience, found that seagrass depends on these microbes much like humans depend on gut bacteria. When antibiotics from sewage and fish farms reach the ocean, they can disrupt that relationship. In lab experiments, seagrass exposed to common antibiotics for one week grew slower, lost pigment, and flipped from a net carbon sink to a net carbon source. That raises concerns for blue carbon projects and coastal restoration. If polluted water kills the helpful bacteria, planting seagrass alone may not restore a functioning carbon sink. The research also points to practical next steps: better wastewater treatment, limits on antibiotic use in aquaculture, and careful site selection for restoration. For anyone tracking blue carbon or coastal climate policy, this is a useful update on why microbial health matters.
