Functionally diverse microbial communities show resilience in response to a record-breaking rain event

Abstract

Estuaries provide many ecosystem services and host a majority of the world’s population. Here, the response of microbial communities after a record-breaking flood event in a highly urbanized estuary was followed. Hurricane Harvey (hereafter Harvey) was a category 4 hurricane that made landfall on the Texas coast in 2017 and lashed the Houston area with 1.4–1.7 × 1010 m3 of rainfall, disrupting the natural gradients of nutrients and salinity. Here, we utilized metagenomics to analyze how Harvey altered the microbial community of Galveston Bay over five weeks following the storm. We hypothesized that the community would shift from a marine dominated community to that of a terrestrial and freshwater origin. We found that following the storm there were changes in the distribution of species with specific metabolic capacities, such as Cyanobacteria, enriched in oxygenic photosynthesis and nitrogen fixation genes, as well as Verrucomicrobia and Betaproteobacteria, with high prevalence of the SOX complex and anoxygenic photosynthesis genes. On the other hand, dominant members of the community with more diverse metabolic capabilities showed less fluctuations in their distribution. Our results highlight how massive precipitation disturbances can alter microbial communities and how the coalescence of diverse microorganisms creates a resilient community able to maintain ecosystem services even when the system is in an altered state.

Response of a phytoplankton community in a subtropical estuary to a pulse disturbance driven by a combo hurricane and rainfall event.

“…6). These shifts in physiology align with ndings on the genomic potential of the microbial community (Walker et al 2022). Brie y, using KEGG classi cations, they found that genes associated with common photosynthetic processes (photosystems I and II, cytochrome b6f, and photosynthetic antenna proteins) decreased and never fully recovered to pre-Harvey levels.…”

“…While it appears that in some cases phytoplankton communities can quickly return to their original composition and abundance, their resilience, or their ability to recover after a pulse disturbance requires further study (Shade et al 2012;Huang et al 2021). Important characteristics of resilient microbes (bacteria, archaea, phytoplankton) are thought to be dormancy, speciation rates, horizontal gene transfer, community composition, functionality (e.g., Philippot et al 2021;Walker et al 2022), while environmental characteristics in estuaries such as water residence times, distance from in ows and magnitude/duration of river discharge are often examined (Roelke et al 2013; Pinckney et al 2017;Paerl et al 2019). It has been observed amongst bacteria that there are dominant "core" taxonomic and functional groups that remain in ecosystems despite changes induced during disturbances (Kurm et al 2019; Walker et al 2022); this is one form of community resilience which can be measured quantitatively.…”

“…Important characteristics of resilient microbes (bacteria, archaea, phytoplankton) are thought to be dormancy, speciation rates, horizontal gene transfer, community composition, functionality (e.g., Philippot et al 2021;Walker et al 2022), while environmental characteristics in estuaries such as water residence times, distance from in ows and magnitude/duration of river discharge are often examined (Roelke et al 2013; Pinckney et al 2017;Paerl et al 2019). It has been observed amongst bacteria that there are dominant "core" taxonomic and functional groups that remain in ecosystems despite changes induced during disturbances (Kurm et al 2019; Walker et al 2022); this is one form of community resilience which can be measured quantitatively. Similarly, amongst the phytoplankton, cyanobacteria and diatoms often are the rst to respond after a disturbance in estuarine or marine waters (Dorado et al 2015;Steichen et al 2020).…”

When biodiversity preservation meets biotechnology: The challenge of developing synthetic microbiota for resilient sustainable crop production

“…A variegate functional composition of a microbiota should be preserved to make the community capable of facing environmental perturbations (Walker et al, 2022). Some measurables are needed to define the relationship between ecosystem function and diversity.…”