Sedimentation stress in a scleractinian coral exposed to terrestrial and marine sediments with contrasting physical, organic and geochemical properties

摘要: Terrestrial runoff increases siltation and nutrient availability on coastal coral reefs worldwide. However the factors determining stress in corals when exposed to short-term sedimentation, including interactions between sediments nutrients, are little understood. We ten different sediment types at environmentally relevant concentrations (33 160 mg DW cm−2) exposure times (12 60 h) laboratory field experiments. The originated from 2 estuaries, nearshore one offshore locations also included ground-up aragonite. For two of these sediments, three grain size fractions were used (silt < 63 μm, fine sand: 63–250 μm, medium 250–500 μm). Sediments characterised by 19 parameters grouped into “physical”, “organic nutrient-related” “geochemical” parameters. Changes photosynthetic yield Montipora peltiformis was measured pulse–amplitude modulated chlorophyll fluorometry (PAM) as proxy for photophysiological exposure, determine rates recovery. Different exerted greatly contrasting levels corals. Our results show that organic nutrient-related properties key sedimentation after exposure. Photophysiological measurable 36 h most silt-sized recovery incomplete 48 96 h time. four sandy caused no same concentration Stress strongly related values sediment, weakly physical unrelated geochemical measured. M. removed classes more easily than silt, nutrient-poor nutrient-rich sediments. Anoxia developed surfaces silts, which had become slimy smelled hydrogen sulphide, suggesting increased bacterial activity. finding can short while or silts affect a lesser extent, will help refining predictions threats given environmental conditions.