Browsing by Author "Coy, Samantha R."

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    Consumer feces impact coral health in guild-specific ways
    (Frontiers Media S.A., 2023) Grupstra, Carsten G. B.; Howe-Kerr, Lauren I.; van der Meulen, Jesse A.; Veglia, Alex J.; Coy, Samantha R.; Correa, Adrienne M. S.
    Animal waste products are an important component of nutrient cycles and result in the trophic transmission of diverse microorganisms. There is growing recognition that the feces of consumers, such as predators, may impact resource species, their prey, via physical effects and/or microbial activity. We tested the effect of feces from distinct fish trophic groups on coral health and used heat-killed fecal controls to tease apart physical versus microbial effects of contact with fecal material. Fresh grazer/detritivore fish feces caused lesions more frequently on corals, and lesions were 4.2-fold larger than those from sterilized grazer/detritivore feces; in contrast, fresh corallivore feces did not cause more frequent or larger lesions than sterilized corallivore feces. Thus, microbial activity in grazer/detritivore feces, but not corallivore feces, was harmful to corals. Characterization of bacterial diversity in feces of 10 reef fish species, ranging from obligate corallivores to grazer/detritivores, indicated that our experimental findings may be broadly generalizable to consumer guild, since feces of some obligate corallivores contained ~2-fold higher relative abundances of coral mutualist bacteria (e.g., Endozoicomonadaceae), and lower abundances of the coral pathogen, Vibrio coralliilyticus, than feces of some grazer/detritivores. These findings recontextualize the ecological roles of consumers on coral reefs: although grazer/detritivores support coral reef health in various ways (e.g., promoting coral settlement and herbivory through the removal of detritus and sediments from the algal matrix), they also disperse coral pathogens. Corallivore predation can wound corals, yet their feces contain potentially beneficial coral-associated bacteria, supporting the hypothesized role of consumers, and corallivores in particular, in coral symbiont dispersal. Such consumer-mediated microbial dispersal as demonstrated here has broad implications for environmental management.
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    Visualization of RNA virus infection in a marine protist with a universal biomarker
    (Springer Nature, 2023) Coy, Samantha R.; Utama, Budi; Spurlin, James W.; Kim, Julia G.; Deshmukh, Harshavardhan; Lwigale, Peter; Nagasaki, Keizo; Correa, Adrienne M. S.
    Half of the marine virosphere is hypothesized to be RNA viruses (kingdom Orthornavirae) that infect abundant micro-eukaryotic hosts (e.g. protists). To test this, quantitative approaches that broadly track infections in situ are needed. Here, we describe a technique—dsRNA-Immunofluorescence (dsRIF)—that uses a double-stranded RNA (dsRNA) targeting monoclonal antibody to assess host infection status based on the presence of dsRNA, a replicative intermediate of all Orthornavirae infections. We show that the dinoflagellate Heterocapsa circularisquama produces dsRIF signal ~ 1000 times above background autofluorescence when infected by the + ssRNA virus HcRNAV. dsRNA-positive virocells were detected across > 50% of the 48-h infection cycle and accumulated to represent at least 63% of the population. Photosynthetic and chromosomal integrity remained intact during peak replication, indicating HcRNAV infection does not interrupt these processes. This work validates the use of dsRIF on marine RNA viruses and their hosts, setting the stage for quantitative environmental applications that will accelerate understanding of virus-driven ecosystem impacts.