Australian Institute of Marine Science (AIMS), Townsville, QLD and Perth, WA, Australia.
Western Australian Marine Science Institution, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Sci Rep. 2020 Mar 16;10(1):4762. doi: 10.1038/s41598-020-61712-w.
Dredging increases suspended sediment concentrations (SSCs), causing elevated water turbidity (cloudiness) and light attenuation. Close to dredging, low light periods can extend over many days, affecting phototrophic epibenthic organisms like corals. To improve the ability to predict and manage dredging impacts, we tested the response of corals to an extended period of elevated turbidity using an automated sediment dosing system that precisely controlled SSCs and adjusted light availability accordingly. Replicates of four common species of corals encompassing different morphologies were exposed to turbidity treatments of 0-100 mg L SSC, corresponding to daily light integrals of 12.6 to 0 mol quanta m d, over a period of ∼7 weeks. Symbiotic dinoflagellate density and algal pigment concentration, photosynthetic yields, lipid concentrations and ratios and growth varied among the turbidity treatments, with corals exhibiting photoacclimation within low turbidity treatments. A range of physiological responses were observed within the high turbidity treatments (low light), including bleaching and changes in lipid levels and ratios. Most corals, except P. damicornis, were capable of adjusting to a turbidity treatment involving a mean light level of 2.3 mol photons m d in conjunction with a SSC of 10 mg L over the 7 week period.
疏浚会增加悬浮泥沙浓度 (SSC)，导致水体浊度升高 (浑浊) 和光衰减。在疏浚附近，低光期可能会持续数天，影响珊瑚等光养附生生物。为了提高预测和管理疏浚影响的能力，我们使用自动化泥沙投加系统测试了珊瑚对延长高浊度期的反应，该系统能够精确控制 SSC，并相应调整光的可用性。我们将四种常见珊瑚的重复样本暴露于 0-100mg/L SSC 的浊度处理中，对应的每日光积分分别为 12.6 至 0mol 量子 m d，持续约 7 周。共生甲藻密度和藻类色素浓度、光合作用产量、脂质浓度和比例以及生长在浊度处理之间有所不同，珊瑚在低浊度处理中表现出光驯化。在高浊度处理（低光）中观察到一系列生理反应，包括白化和脂质水平和比例的变化。除了 P. damicornis 外，大多数珊瑚都能够适应持续 7 周、平均光照水平为 2.3mol 光子 m d 并伴有 10mg/L SSC 的浊度处理。
