Pinnow Nicole, Chibani Cynthia M, Güllert Simon, Weiland-Bräuer Nancy
General Microbiology, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
Current address: Sysmex Inostics GmbH, Falkenried 88, 20251, Hamburg, Germany.
Anim Microbiome. 2023 Sep 21;5(1):45. doi: 10.1186/s42523-023-00266-4.
Climate change globally endangers certain marine species, but at the same time, such changes may promote species that can tolerate and adapt to varying environmental conditions. Such acclimatization can be accompanied or possibly even be enabled by a host's microbiome; however, few studies have so far directly addressed this process. Here we show that acute, individual rises in seawater temperature and salinity to sub-lethal levels diminished host fitness of the benthic Aurelia aurita polyp, demonstrated by up to 34% reduced survival rate, shrinking of the animals, and almost halted asexual reproduction. Changes in the fitness of the polyps to environmental stressors coincided with microbiome changes, mainly within the phyla Proteobacteria and Bacteroidota. The absence of bacteria amplified these effects, pointing to the benefit of a balanced microbiota to cope with a changing environment. In a future ocean scenario, mimicked by a combined but milder rise of temperature and salinity, the fitness of polyps was severely less impaired, together with condition-specific changes in the microbiome composition. Our results show that the effects on host fitness correlate with the strength of environmental stress, while salt-conveyed thermotolerance might be involved. Further, a specific, balanced microbiome of A. aurita polyps supports the host's acclimatization. Microbiomes may provide a means for acclimatization, and microbiome flexibility can be a fundamental strategy for marine animals to adapt to future ocean scenarios and maintain biodiversity and ecosystem functioning.
全球气候变化危及某些海洋物种，但与此同时，这种变化可能会促进能够耐受和适应不断变化的环境条件的物种。这种适应过程可能伴随着宿主的微生物群，甚至可能由其促成；然而，到目前为止，很少有研究直接探讨这一过程。在这里，我们表明，海水温度和盐度急剧、个体性地上升到亚致死水平会降低底栖海月水母水螅体的宿主适应性，这表现为存活率降低高达34%、动物体型缩小以及无性繁殖几乎停止。水螅体对环境应激源适应性的变化与微生物群的变化同时发生，主要发生在变形菌门和拟杆菌门内。细菌的缺失放大了这些影响，表明平衡的微生物群有助于应对不断变化的环境。在未来海洋情景中，模拟温度和盐度的联合但较温和的上升，水螅体的适应性受到的损害要小得多，同时微生物群组成也有特定条件下的变化。我们的结果表明，对宿主适应性的影响与环境应激的强度相关，而盐传递的耐热性可能也起作用。此外，海月水母水螅体特定的、平衡的微生物群支持宿主的适应。微生物群可能提供一种适应方式，微生物群的灵活性可能是海洋动物适应未来海洋情景并维持生物多样性和生态系统功能的基本策略。
