Spatial and diel patterns of volatile organic compounds, DMSP-derived compounds, and planktonic microorganisms around a tropical scleractinian coral colony

Volatile organic compounds (VOCs) are constituents of marine ecosystems including coral reefs, where they sources atmospheric reactivity, indicators ecosystem state, components defense strategies, and infochemicals. Most VOCs result from sunlight-related processes; however, their light-driven dynamics still poorly understood. We studied the spatial variability a suite VOCs, dimethylsulfide (DMS), other dimethylsulfoniopropionate-derived (DMSPCs), namely, DMSP, acrylate, dimethylsulfoxide (DMSO), in waters around colonies two scleractinian corals ( Acropora pulchra Pocillopora sp.) brown seaweed Turbinaria ornata Mo’orean French Polynesia. Concentration gradients indicated that were DMSPCs, but less or null than DMS, while was source carbonyl sulfide (COS), poly-halomethanes. A focused study conducted an A. colony VOC DMSPC concentrations free-living microorganism abundances monitored every 6 h over 30 h. near polyps paralleled sunlight intensity, with large diurnal increases nocturnal decrease. rDNA metabarcoding metagenomics allowed determination microbial diversity relative abundance target functional genes. Seawater enriched DMS as only VOC, plus DMSO, increase during day, coinciding high symbiodiniacean sequences. Only 10 cm below, skeleton colonized by turf alga, much lower community significantly different. Two meters down current coral, DMSPCs decreased further more similar to alga. Several DMSP cycling genes near-polyp respect down-current waters, eukaryotic production oxidation encoding genes, attributed algal symbiont, prokaryotic gene dddD , harbored coral-associated Gammaproteobacteria . Our results suggest solar radiation-induced oxidative stress caused release holobiont, either directly through symbiont expulsion. Strong chemical biological occurred water between branches, which we attribute layered hydrodynamics.