Microbial predictors of environmental perturbations in coral reef ecosystems

Abstract

22times less affected by the environment and their community assembly patterns were 34 generally less uniform. Further, seawater microbial community data provided an 35 accurate prediction on the environmental state, highlighting the diagnostic value of 36 microorganisms and illustrating how long-term coral reef monitoring initiatives could 37 be enhanced by incorporating assessments of microbial communities in seawater. 38

Peer Review #1 of "Microbiome dynamics in the tissue and mucus of acroporid corals differ in relation to host and environmental parameters (v0.1)"

“…Microbial communities associated with corals are continually exposed to fluctuations in the surrounding environment and the physiology of their host. Previous studies have demonstrated changes in the coral microbiome in response to thermal stress (Ainsworth & Hoegh-Guldberg, 2009;Grottoli et al, 2018;Lee et al, 2015;Thurber et al, 2009), ocean acidification (Grottoli et al, 2018;Thurber et al, 2009), organic matter enrichment (Garren & Azam, 2012), bleaching events (Bourne et al, 2008) and other environmental and physiological factors (Glasl et al, 2019a;Guppy & Bythell, 2006;Kelly et al, 2014;Li et al, 2015;Pollock et al, 2018). However, the coral microbiome is not homogenous across the animal and an improved understanding of the sensitivity of the microorganisms inhabiting each coral compartment is needed.…”

“…Manuscript to be reviewed Samples (n = 3 per sample type and per sampling event) for molecular analysis were collected as part of the Australian Microbiome Initiative and the sample procedure has previously been outlined by Glasl et al (2019a). In brief, coral nubbins (approximately cm tall) of both Acropora species were collected, rinsed with 0.2 µm filter-sterilized seawater and placed into cryogenic vials.…”

“…Coral nubbins, mucus swabs and Sterivex filters were immediately snap frozen in liquid nitrogen after collection and stored at -80°C until further processing. To acquire environmental information, water and sediment samples were collected in duplicate for each sampling event as described in Glasl et al (2019a) and further analyzed according to the standard procedures of Australian Institute of Marine Science (Devlin & Lourey, 2000). The environmental information processed includes common reef water quality measures such as salinity, particulate organic carbon, total suspended solids, concentrations of chlorophyll a, ammonium, the sum of nitrite and nitrate, particulate nitrogen, nitrite, total nitrogen, non-purgeable organic carbon, non-purgeable inorganic carbon, phosphate and silica as well as total organic carbon in the sediment, total organic nitrogen in the sediment and grainsize percentage of sediments < 0.63 m, between 0.63 m and 2 mm, and > 2 mm.…”

“…A table containing the samples and their read abundances was created and the zOTUs were taxonomically classified with SILVA v132 database (Yilmaz et al, 2014) using MOTHUR's implementation of the Wang classifier (Wang et al, 2007) and a 60% Bayesian probability cut-off. This sequencing dataset has already been used in a previous contribution by the research group (Glasl et al, 2019a), but in the current study it is analyzed from a different perspective aiming at comparing temporal microbiome dynamics between two distinct coral compartments.…”

“…For instance, Li et al (2015) reported a dynamic relationship between the community structure of coral-associated bacteria and the seasonal variation in environmental parameters such as dissolved oxygen and rainfall. Glasl et al (2019a) showed that although host-associated microbiomes were five-times less responsive to the environment compared to the seawater microbiome, they were still affected by environmental factors (e.g. temperature, turbidity, and nutrient concentration).…”