The effects of dissolved organic matter supplements on the metabolism of corals under heat stress

Octocorals represent a major alternative group in the benthic community of reefs that have diverged from hexacoral dominance. Despite their phototrophic symbionts, supplementing their diet with heterotrophic sources may promote their growth, particularly when compared to hexacorals in bleaching conditions. However, limited comprehensive data exists on octocorals' trophic ecology, especially regarding their ability to feed on dissolved organic matter (DOM), which comprises the largest pool of organic matter in reefs. This study aims to investigate the ability of two octocorals (Sarcophyton glaucum and Lobophytum sp.) to feed on DOM and compare this ability to that of hexacorals, such as Stylophora pistillata and Turbinaria reniformis. The study measured the net fluxes of DOM under varying DOM concentrations and under heat stress. The results demonstrate that all coral species were net producers of DOM at ambient concentrations, but became net consumers once seawater was supplemented with...

八放珊瑚（Octocorals）是脱离六放珊瑚主导格局的珊瑚礁底栖群落中的主要类群。尽管其体内存在光合共生体，但通过异养来源补充营养或可促进其生长，相较于白化环境中的六放珊瑚，这一效应尤为显著。然而，目前关于八放珊瑚营养生态学的综合研究数据仍较为匮乏，尤其是针对其摄取溶解有机物（dissolved organic matter, DOM）的能力——溶解有机物是珊瑚礁中体量最大的有机物库。本研究旨在探究两种八放珊瑚，即肉质软珊瑚（Sarcophyton glaucum）与肉芝软珊瑚属未定种（Lobophytum sp.）对溶解有机物的摄取能力，并将该能力与杯形珊瑚（Stylophora pistillata）、盾形陀螺珊瑚（Turbinaria reniformis）等六放珊瑚的同类能力进行对比。本研究测定了不同溶解有机物浓度以及热胁迫条件下的溶解有机物净通量。结果显示，所有珊瑚物种在环境浓度下均为溶解有机物的净生产者，但当海水补充添加……