Award: OCE-1801367

On August 25, Hurricane Harvey made landfall on San Jose Island, TX as a category 4 storm. During the subsequent five days, precipitation reached over 130 cm of rain in the Houston area, causing city-wide flooding. Large amounts of freshwater from the floodwater/runoff inundated Galveston Bay, causing decreases in salinity and increases in organic material. We performed a transect from the mouth of the San Jacinto river to the Gulf of Mexico over the six weeks following the storm. Metagenomics was used to chracterize the changes in diversity and metabolic potential of nannoplankton, prokaryotes and viruses. Hurricane Harvey flooding introduced freshwater, terrestrial, and sedimentary bacteria in Galveston Bay. The prokaryotic communities bounced back to pre-Harvey composition within six weeks. Metagenomics revealed a progression of metabolic pathways after the storm from acommunity dominated by heterotrophs to a community dominated by primary producers after recovery. The storm washed out the viruses, slowing down viral activity. As viral activity came back, the incidence of viral infections remained higher than pre-Harvey levels. The same trend was observed for the incidence of lysogeny, suggesting a large role of viruses in their host resilience to change. This study shows that microbial communities can quickly recover from an extreme event such as a hurricane or flooding event to maintain the ecosystem equilibrium. Due to the intensifying conditions of hurricanes, it is important to understand how the marine microbial community is impacted and how it recovers after a severe environmental stressor. Last Modified: 02/28/2020 Submitted by: Jessica Labonte