Physiology of the widespread pulsating soft coral Xenia umbellata is affected by food sources, but not by water flow

Coral energy and nutrient acquisition strategies are complex and sensitive to environmental conditions such as water flow. While high water flow can enhance feeding in hard corals, knowledge about the effects of water flow on the feeding of soft corals, particularly those pulsating, is still limited. In this study, we thus investigated the effects of feeding and water flow on the physiology of the pulsating soft coral Xenia umbellata. We crossed three feeding treatments i) no feeding, ii) particulate organic matter [POM] as phytoplankton, and iii) dissolved organic carbon [DOC] as glucose, with four water volume exchange rates (200, 350, 500 and 650 Lh-1) over 15 days. Various ecophysiological parameters were assessed including pulsation rate, growth rate, isotopic and elemental ratios of carbon (C) and nitrogen (N) as well as photo-physiological parameters of the Symbiodiniaceae (cell density, chlorophyll-a and mitotic index). Water flow had no significant effect but feeding had a subs..., An aquarium experiment was carried out on soft coral Xenia umbellata at the University of Bremen, Germany, crossing 3 feeding treatments (no feeding, phytoplankton and DOC) with four water flow treatments (200, 350, 500 and 650 Lh-1). Various physiological parameters were assessed. Data was subsequently analysed using R statistical software., Microsoft Excel

珊瑚的能量与营养获取策略复杂且对水流等环境条件极为敏感。尽管高水流可增强硬珊瑚的摄食能力，但当前学界对水流影响软珊瑚（尤其是搏动型软珊瑚）摄食的认知仍较为有限。本研究以搏动型软珊瑚伞形接枝珊瑚（Xenia umbellata）为研究对象，探究了摄食与水流对其生理特性的影响。实验设置3种摄食处理组：①无投喂组、②以浮游植物为基质的颗粒有机物（Particulate Organic Matter, POM）投喂组、③以葡萄糖为基质的溶解有机碳（Dissolved Organic Carbon, DOC）投喂组，并与4种水体体积交换速率（200、350、500及650 Lh⁻¹）开展交叉实验，实验周期共计15天。本研究评估了多项生态生理参数，包括搏动频率、生长速率、碳（C）与氮（N）的同位素及元素比值，以及虫黄藻（Symbiodiniaceae）的光生理参数（细胞密度、叶绿素a含量与有丝分裂指数）。水流未产生显著影响，但摄食对相关指标存在显著作用（原文内容截断）。本实验于德国不来梅大学开展伞形接枝珊瑚的水族箱饲养实验，将3种摄食处理与4种水流处理进行交叉设计，并测定了多项生理参数。后续实验数据采用R统计软件与Microsoft Excel进行分析。