Manikandan B, Sawant P, Maurya P K, Pal Ashish, Naik T A, Ravindran J, Paul Sayeri, Lad T, Prabhudesai S, Jayakumar K
CSIR-National Institute of Oceanography, Donapaula, Goa, 403004, India.
CSIR-National Institute of Oceanography, Donapaula, Goa, 403004, India.
Mar Environ Res. 2025 Oct;211:107453. doi: 10.1016/j.marenvres.2025.107453. Epub 2025 Aug 14.
The ever increasing dominance of macroalgae on coral reefs is posing new challenges for coral growth and reef resilience. As a part of the continuous coral community monitoring program in Gulf of Mannar Marine Biosphere Reserve (GoMBR) in India, we observed that a few species of macroalgae were persistent throughout the year and remained in physical contact with corals. The effects of such competitive macroalgal interaction on the functional traits of corals are least understood. A series of insitu experiments were conducted to investigate the impact of three macroalgal species on the calcification rates of two Indo-Pacific corals, Acropora muricata and Porites lutea, through alterations in seawater carbonate chemistry. The experimental results showed that macroalgae increased the pH and aragonite saturation state (Ω) throughout the day, that remained stable at night. This created a conducive environment for the corals to maintain their net calcification even at night. However, the corals A. muricata and P. lutea displayed a mixed response, wherein the net calcification rate of the former was enhanced and the latter was significantly reduced in the presence of macroalgae, irrespective of the species. Such disparity in the calcification rates between coral species indicates both affirmative and detrimental effects of coral-macroalgal interactions, highlighting the significance of considering the species-specific interactions between corals and macroalgae in the context of climate change and coral-macroalgal phase-shifts.
大型海藻在珊瑚礁上的优势地位不断增强，这给珊瑚生长和珊瑚礁恢复力带来了新挑战。作为印度马纳尔湾海洋生物保护区（GoMBR）持续进行的珊瑚群落监测项目的一部分，我们观察到一些大型海藻物种全年都存在，并与珊瑚保持物理接触。这种竞争性大型海藻相互作用对珊瑚功能性状的影响鲜为人知。我们进行了一系列原位实验，通过改变海水碳酸盐化学性质，研究三种大型海藻物种对两种印度 - 太平洋珊瑚——多孔鹿角珊瑚（Acropora muricata）和淡黄滨珊瑚（Porites lutea）钙化率的影响。实验结果表明，大型海藻全天都能提高海水pH值和文石饱和度状态（Ω），夜间保持稳定。这为珊瑚创造了一个有利环境，使其即使在夜间也能维持净钙化。然而，多孔鹿角珊瑚和淡黄滨珊瑚表现出不同的反应，在有大型海藻存在的情况下，前者的净钙化率提高，而后者则显著降低，且与大型海藻物种无关。珊瑚物种之间钙化率的这种差异表明了珊瑚 - 大型海藻相互作用既有积极影响也有不利影响，凸显了在气候变化和珊瑚 - 大型海藻相移背景下考虑珊瑚与大型海藻物种特异性相互作用的重要性。
