The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel.
The Interuniversity Institute for Marine Sciences, Eilat 88103, Israel.
Sci Rep. 2017 Jan 9;7:40288. doi: 10.1038/srep40288.
Climate change, including ocean acidification (OA), represents a major threat to coral-reef ecosystems. Although previous experiments have shown that OA can negatively affect the fitness of reef corals, these have not included the long-term effects of competition for space on coral growth rates. Our multispecies year-long study subjected reef-building corals from the Gulf of Aqaba (Red Sea) to competitive interactions under present-day ocean pH (pH 8.1) and predicted end-of-century ocean pH (pH 7.6). Results showed coral growth is significantly impeded by OA under intraspecific competition for five out of six study species. Reduced growth from OA, however, is negligible when growth is already suppressed in the presence of interspecific competition. Using a spatial competition model, our analysis indicates shifts in the competitive hierarchy and a decrease in overall coral cover under lowered pH. Collectively, our case study demonstrates how modified competitive performance under increasing OA will in all likelihood change the composition, structure and functionality of reef coral communities.
气候变化，包括海洋酸化（OA），对珊瑚礁生态系统构成了重大威胁。尽管先前的实验表明 OA 可能会对珊瑚的适应能力产生负面影响，但这些实验并未包括对珊瑚生长率的空间竞争的长期影响。我们的多物种为期一年的研究在当前海洋 pH 值（8.1）和预测本世纪末海洋 pH 值（7.6）下，使来自亚喀巴湾（红海）的造礁珊瑚承受种内竞争的相互作用。结果表明，在 6 种研究物种中的 5 种中，OA 会显著抑制珊瑚的生长。然而，当种间竞争已经抑制了生长时，OA 导致的生长减少可以忽略不计。利用空间竞争模型，我们的分析表明，在降低 pH 值的情况下，竞争层次会发生变化，整体珊瑚覆盖率会下降。总的来说，我们的案例研究表明，在不断增加的 OA 下，竞争表现的变化很可能会改变珊瑚礁群落的组成、结构和功能。
