Ecological niche segregation of anaerobic ammonium oxidizing (anammox) bacteria under saline environments remains unresolved despite its ecological and practical importance. In this study, niche segregation by salinity for Ca. Brocadia sinica, Ca. Jettenia caeni, Ca. Kuenenia stuttgartiensis and Ca. Scalindua sp. was systematically studied. The inhibitory effect of salinity on specific anammox activity (SAA) was measured experimentally and model-fitted to obtain the salinity-dependent maximum specific growth rates (µmax). The resulting µmax were incorporated into a Monod growth model with nitrite as the limiting substrate to predict which anammox bacterial species would dominate at a given salinity. The model predictions revealed that there were threshold salinity ranges where specific growth rates were comparable and the determining factor for the dominant species was the availability of nitrite. Ca. B sinica, Ca. J. caeni, and Ca. K. stuttgartiensis could compete at 0 - 0.5% salinity, while Ca. K. stuttgartiensis and Ca. Scalindua sp. could coexist at around 2% salinity. The model prediction was validated by conducting interspecific competition experiments among the four anammox species in nitrite-limiting membrane bioreactors (MBRs) under different salinity concentrations. The interspecific competition experiments showed that Ca. K. stuttgartiensis with relatively high affinity for nitrite was dominant at a wide range of salinities from 0.25 to 1.75%. Outside this salinity range, Ca. B. sinica was dominant at salinity 0 %, and Ca. Scalindua sp. outcompeted exclusively the other species due to its high salinity tolerance at salinities above 2.0%. These experimental results are in good agreement with the model predictions, demonstrating the validity of the Monod model in accounting for salinity inhibition and reflecting the salinity-dependent distributions of anammox bacteria reported in a variety of engineered and natural saline environments.

中文翻译：

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不同盐度下厌氧氨氧化菌的种间竞争和适应：盐度抑制 Monod 生长模型的实验验证


尽管厌氧氧化铵 （anammox） 细菌具有生态和实际重要性，但在盐水环境中的生态位分离仍未解决。在这项研究中，系统研究了 Ca. Brocadia sinica、Ca. Jettenia caeni、Ca. Kuenenia stuttgartiensis 和 Ca. Scalindua sp. 的盐度生态位分离。通过实验测量盐度对比厌氧氨氧化活性 （SAA） 的抑制作用，并进行模型拟合以获得盐度依赖性最大比生长速率 （μmax）。将得到的 μmax 纳入以亚硝酸盐为限制底物的 Monod 生长模型中，以预测在给定盐度下哪些厌氧氨氧化细菌物种将占主导地位。模型预测显示，存在阈值盐度范围，其中比增长率相当，主要物种的决定因素是亚硝酸盐的可用性。Ca. B sinica、Ca. J. caeni 和 Ca. K. stuttgartiensis 可以在 0 - 0.5% 的盐度下竞争，而 Ca. K. stuttgartiensis 和 Ca. Scalindua sp. 可以在大约 2% 的盐度下共存。通过在不同盐度浓度下亚硝酸盐限制膜生物反应器 （MBR） 中对 4 种厌氧氨氧化物质进行种间竞争实验，验证了模型预测的有效性。种间竞争实验表明，对亚硝酸盐具有相对较高的亲和力的 Ca. K. stuttgartiensis 在 0.25 至 1.75% 的宽盐度范围内占主导地位。在这个盐度范围之外，Ca. B. sinica 在盐度为 0 % 时占主导地位，而 Ca. Scalindua sp. 由于在盐度高于 2.0% 时具有高耐盐性，因此完全胜过其他物种。 这些实验结果与模型预测非常吻合，证明了 Monod 模型在解释盐度抑制方面的有效性，并反映了在各种工程和天然盐分环境中报告的厌氧氨氧化细菌的盐度依赖性分布。