Brown Kristen T, Bender-Champ Dorothea, Hoegh-Guldberg Ove, Dove Sophie
School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St Lucia, Queensland 4072, Australia.
R Soc Open Sci. 2020 Dec 23;7(12):201797. doi: 10.1098/rsos.201797. eCollection 2020 Dec.
Understanding the effects of natural processes on coral-algal competition is an important step in identifying the role of macroalgae in perturbed coral reef ecosystems. However, studies investigating coral-algal interactions are often conducted in response to a disturbance, and rarely incorporate seasonal variability. Here, naturally occurring coral-algal interactions were assessed four times a year over 2 years across eight sites spanning diverse benthic communities. In over 6500 recorded coral-algal interactions, cyanobacteria and turf algae were found to be the most damaging regardless of season, resulting in visible damage to coral in greater than 95% of interactions. Macroalgae that primarily compete using chemical mechanisms were found to be more damaging than those that compete using physical mechanisms (e.g. abrasion), with both groups demonstrating decreased competitive ability in summer. While crustose coralline algae were the least damaging to competing coral, during summer, it became three times more competitive. Our results demonstrate that the competitive ability of macroalgae and the outcomes of coral-algal competition can fluctuate in seasonal cycles that may be related to biomass, production of chemical defences and/or physical toughness. The results of this study have important implications for understanding the trajectory and resilience of coral reef ecosystems into the future.
了解自然过程对珊瑚 - 藻类竞争的影响是确定大型藻类在受到干扰的珊瑚礁生态系统中作用的重要一步。然而，研究珊瑚 - 藻类相互作用的研究通常是针对干扰进行的，很少考虑季节变化。在这里，在两年时间里，每年对跨越不同底栖生物群落的八个地点进行四次自然发生的珊瑚 - 藻类相互作用评估。在超过6500次记录的珊瑚 - 藻类相互作用中，发现蓝藻和草皮藻无论季节如何都是最具破坏性的，在超过95%的相互作用中对珊瑚造成可见损害。发现主要利用化学机制竞争的大型藻类比利用物理机制（如磨损）竞争的大型藻类更具破坏性，两组在夏季的竞争能力都有所下降。虽然壳状珊瑚藻对竞争珊瑚的损害最小，但在夏季，其竞争力提高了两倍。我们的结果表明，大型藻类的竞争能力和珊瑚 - 藻类竞争的结果可能会在季节性周期中波动，这可能与生物量、化学防御的产生和/或物理韧性有关。这项研究的结果对于理解未来珊瑚礁生态系统的发展轨迹和恢复力具有重要意义。
