Titelboim Danna, Dedman Craig J, Hodgson Rose Pian, Knowles Lucy S, Liu Xuan, Lenzi Luca, Tudor Jack, Vamos Edith, Rickaby Rosalind E M
University of Oxford, Oxford, UK.
University of Sheffield, Sheffield, UK.
Proc Biol Sci. 2025 Jun;292(2049):20250596. doi: 10.1098/rspb.2025.0596. Epub 2025 Jun 18.
Many marine calcifiers engage in obligatory algal symbiosis which is threatened by ocean warming. Large benthic foraminifera are prominent carbonate and sand producers in shallow environments with a wide range of species-specific thermal tolerances assumed to be related to their diverse algal symbionts. We examine two diatom-bearing benthic foraminifera species which differ in their thermal physiological tolerance and symbiont community composition. Our findings demonstrate that the less thermally tolerant host, Larsen, 1976, 'shuffles' the dominant players of the internal symbiont community with increasing temperature while the more thermally tolerant host McCulloch, 1977, is dominated by Medlin, 1990, at all temperatures. Although this diatom species was present in from all treatments, it became more abundant only under the most severe temperature stress. Symbionts were isolated from the thermally tolerant foraminifera , with only one species of symbiont surviving at 35°C, while the others failed to survive at 32°C. Supplementation of isolated symbionts reduced bleaching of under heat stress suggesting that while increased temperature creates shuffling at the family level, heat tolerance of the holobiont is related to changes at the species level of the symbiont algae.
许多海洋钙化生物会进行 obligatory 藻类共生，而这种共生正受到海洋变暖的威胁。大型底栖有孔虫是浅水环境中重要的碳酸盐和沙子生产者，它们具有广泛的物种特异性热耐受性，据推测这与它们多样的藻类共生体有关。我们研究了两种含硅藻的底栖有孔虫物种，它们在热生理耐受性和共生体群落组成上存在差异。我们的研究结果表明，热耐受性较差的宿主（Larsen，1976）会随着温度升高“洗牌”内部共生体群落的主要成员，而热耐受性较强的宿主（McCulloch，1977）在所有温度下都以（Medlin，1990）为主导。尽管这种硅藻物种在所有处理中都存在，但只有在最严重的温度胁迫下它才变得更加丰富。共生体从热耐受性有孔虫中分离出来，只有一种共生体在35°C下存活，而其他共生体在32°C时未能存活。添加分离出的共生体减少了热胁迫下（此处原文缺失具体物种）的白化现象，这表明虽然温度升高会在科水平上造成“洗牌”，但共生体藻类的物种水平变化与共生生物整体的耐热性有关。
