Chase T J, Pratchett M S, McWilliam M J, Hein M Y, Tebbett S B, Hoogenboom M O
Marine Biology and Aquaculture Group, College of Science and Engineering, James Cook University, Townsville, Queensland, 4811, Australia.
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia.
R Soc Open Sci. 2020 Apr 29;7(4):192074. doi: 10.1098/rsos.192074. eCollection 2020 Apr.
Mutualisms play a critical role in ecological communities; however, the importance and prevalence of mutualistic associations can be modified by external stressors. On coral reefs, elevated sediment deposition can be a major stressor reducing the health of corals and reef resilience. Here, we investigated the influence of severe sedimentation on the mutualistic relationship between small damselfishes ( and ) and their coral host (). In an aquarium experiment, corals were exposed to sedimentation rates of approximately 100 mg cm d, with and without fishes present, to test whether: (i) fishes influence the accumulation of sediments on coral hosts, and (ii) fishes moderate partial colony mortality and/or coral tissue condition. Colonies with fishes accumulated much less sediment compared with colonies without fishes, and this effect was strongest for colonies with (fivefold less sediment than controls) as opposed to (twofold less sediment than controls). Colonies with symbiont fishes also had up to 10-fold less sediment-induced partial mortality, as well as higher chlorophyll and protein concentrations. These results demonstrate that fish mutualisms vary in the strength of their benefits, and indicate that some mutualistic or facilitative interactions might become more important for species health and resilience at high-stress levels.
互利共生在生态群落中发挥着关键作用；然而，互利共生关系的重要性和普遍性会受到外部压力源的影响。在珊瑚礁上，沉积物沉积增加可能是一个主要压力源，会降低珊瑚的健康状况和珊瑚礁的恢复力。在此，我们研究了严重沉积对小型雀鲷（ 和 ）与其珊瑚宿主（ ）之间互利共生关系的影响。在一项水族箱实验中，让珊瑚暴露于沉积速率约为100毫克/平方厘米·天的环境中，分别设置有鱼和无鱼的情况，以测试：（i）鱼是否会影响珊瑚宿主上沉积物的积累，以及（ii）鱼是否能减轻部分群体死亡率和/或珊瑚组织状况。有鱼的群体比无鱼的群体积累的沉积物少得多，对于有 （沉积物比对照组少五倍）的群体，这种影响最为明显，而有 （沉积物比对照组少两倍）的群体则相对较弱。有共生鱼的群体沉积物诱导的部分死亡率也低至十分之一，同时叶绿素和蛋白质浓度更高。这些结果表明，鱼类互利共生在其益处的强度上存在差异，并表明在高压力水平下，一些互利或促进性相互作用可能对物种健康和恢复力变得更加重要。
