Brown
Anya L.
Brown
Anya L.
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ArticleReshuffling of the coral microbiome during dormancy(American Society for Microbiology, 2022-11-16) Brown, Anya L. ; Sharp, Koty ; Apprill, AmyQuiescence, or dormancy, is a response to stressful conditions in which an organism slows or halts physiological functioning. Although most species that undergo dormancy maintain complex microbiomes, there is little known about how dormancy influences and is influenced by the host's microbiome, including in the temperate coral Astrangia poculata. Northern populations of undergo winter quiescence. Here, we characterized wild microbiomes in a high-resolution sampling time series before, during, and after quiescence using 16S rRNA gene sequencing on active (RNA) and present (DNA) microbiomes. We observed a restructuring of the coral microbiome during quiescence that persisted after reemergence. Upon entering quiescence, corals shed copiotrophic microbes, including putative pathogens, suggesting a removal of these taxa as corals cease normal functioning. During and after quiescence, bacteria and archaea associated with nitrification were enriched, suggesting that the quiescent microbiome may replace essential functions through supplying nitrate to corals and/or microbes. Overall, this study demonstrates that key microbial groups related to quiescence in may play a role in the onset or emergence from dormancy and long-term regulation of the microbiome composition. The predictability of dormancy in provides an ideal natural manipulation system to further identify factors that regulate host-microbial associations.Using a high-resolution sampling time series, this study is the first to demonstrate a persistent microbial community shift with quiescence (dormancy) in a marine organism, the temperate coral. Furthermore, during this period of community turnover, there is a shedding of putative pathogens and copiotrophs and an enhancement of the ammonia-oxidizing bacteria () and archaea ("Nitrosopumilus"). Our results suggest that quiescence represents an important period during which the coral microbiome can reset, shedding opportunistic microbes and enriching for the reestablishment of beneficial associates, including those that may contribute nitrate while the coral animal is not actively feeding. We suggest that this work provides foundational understanding of the interplay of microbes and the host's dormancy response in marine organisms.
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ArticleLocal versus site-level effects of algae on coral microbial communities(The Royal Society, 2021-09-15) Briggs, Amy A. ; Brown, Anya L. ; Osenberg, Craig W.Microbes influence ecological processes, including the dynamics and health of macro-organisms and their interactions with other species. In coral reefs, microbes mediate negative effects of algae on corals when corals are in contact with algae. However, it is unknown whether these effects extend to larger spatial scales, such as at sites with high algal densities. We investigated how local algal contact and site-level macroalgal cover influenced coral microbial communities in a field study at two islands in French Polynesia, Mo'orea and Mangareva. At 5 sites at each island, we sampled prokaryotic microbial communities (microbiomes) associated with corals, macroalgae, turf algae and water, with coral samples taken from individuals that were isolated from or in contact with turf or macroalgae. Algal contact and macroalgal cover had antagonistic effects on coral microbiome alpha and beta diversity. Additionally, coral microbiomes shifted and became more similar to macroalgal microbiomes at sites with high macroalgal cover and with algal contact, although the microbial taxa that changed varied by island. Our results indicate that coral microbiomes can be affected by algae outside of the coral's immediate vicinity, and local- and site-level effects of algae can obscure each other's effects when both scales are not considered.
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ArticleEffects of two common antibiotics on the skin microbiome of ornamental reef fishes: Implications for manipulative experiments in microbial dynamics(Wiley, 2024-05-16) Pereira, Ana ; Brown, Anya L. ; Strobel, Davis ; Soares, Marta C. ; Xavier, Raquel ; Apprill, Amy ; Sikkel, Paul C.An understanding of the mechanistic drivers of animal-microbial symbiosis and associations generally requires experiments that manipulate specific symbionts or microbial communities. As part of an ongoing study of the mechanisms that drive microbial communities in coral reef fishes, and specifically the role of cleanerfish in microbial transmission, we tested the effects of the commonly used antibiotics Enrofloxacin and Nitrofurazone on the skin microbiome of three ornamental reef fish species: the four-eyed butterflyfish, Chaetodon capistratus (Chaetodontidae), the cleanerfish neon goby Elacatinus oceanops (Gobiidae) and the beaugregory damselfish Stegastes leucostictus (Pomacentridae). Our main aim was to characterize dysbiosis prompted by the delivery of the two antibiotics and understand whether both could be used to establish good starting points for microbial transmission experiments. We bathed the fish in antibiotic (or no exposure in the controls), sampled the skin microbiota via swabbing at zero (before treatment) and 3 and 7 days during the treatments, and examined the microbial community using a 16S rRNA gene sequencing approach. Nitrofurazone reduced skin-associated microbial diversity in all species, whereas the same effect for Enrofloxacin was only seen in S. leucostictus. Although each antibiotic had its own, unique impact in microbial community, all treatments showed positive and negative shifts in the most abundant microbial taxa over time. Moreover, soon after the delivery of both antibiotics, increases in the abundance of opportunistic bacteria or potential pathogens, such as Alteromonas and Vibrio, were observed. Although both antibiotics are effective, Nitrofurazone more successfully reduces microbial diversity and therefore may be more ideal for experiments seeking to disrupt fish microbiomes.