We report the results of an aquaria-based experiment testing the effects of suspended particles generated during potential mining activities, on a common habitat-building coral species in the Azores, Dentomuricea aff. meteor. Coral fragments were maintained in 10-L aquaria and exposed to three experimental treatments for a period of four weeks at the DeepSeaLab aquaria facilities (Okeanos-University of the Azores): (1) control conditions (no added sediments); (2) suspended polymetallic sulphide (PMS) particles; (3) suspended quartz particles. Gene expression profiles in D. aff. meteor were used to evaluate the physiological pathways involved in the response to exposure to PMS and quartz particles. Coral fragments were collected from each treatment at times 0, 3, and 13 days and for the control and quartz treatments also at time 27 days. The study targeted genes involved in cellular stress and antioxidant reaction system (heat shock protein, superoxide dismutase, ferritin), cell structure/integrity (α-carbonic anhydrase, receptor-type protein tyrosine phosphatase) and immune responses (toll-like receptor, lysozyme, rel homology domain, ferritin).

Gene expression profiles in D. aff. meteor exposed to the different treatmentsHKG: House Keeping Genes (18S and β-actin)RHD: rel homology domain TLR: toll-like receptor HSP70: heat shock protein RP Tyr-PH: receptor-type protein tyrosine phosphatase SOD: superoxide dismutaseCarb Anhy: α-carbonic anhydraseCt = cycle threshold (nº of cycles in an RT-PCR required for the signal to exceed the background level)Relative gene expression of the gene = Relative quantity gene / Geometric mean of the relative quantities of each housekeeping gene (=RQ gene/Geomean RQ HKGs)Relative quantity (RQ) = (efficiency of the gene)^ΔCT