Effect of extracted algal metabolites on larval microbiomes of Pocillopora acuta from Singapore

In controlled experiments, Pocillopora acuta larvae were placed in beakers and exposed to algal exudates from four macroalgae species (Bryopsis sp., Endosiphonia horrida, Hypnea pannosa, and Lobophora sp.) collected from reefs in Singapore. All algal treatments were run at three different exposure concentrations (Low= 0.01mg/ml, Medium= 0.05mg/ml, or High= 0.1mg/ml). Additional control replicates containing sterile seawater and ethanol were also run. Following the 96-hour exposure to algal exudates, the larvae from each beaker (which contained between 20-28 larvae at the start of the experiment) were pooled as a single sample replicate for 16S rRNA gene sequencing of the V4 region. Samples contained a combination of settled and free-swimming larvae. Larvae that died due to the experimental treatment disintegrated quickly; therefore, none of those larvae were included for sequencing.