Abstract Lake water salinity, an important indicator of lake hydrological conditions, is critical to deciphering terrestrial paleoclimatic and paleoenvironmental changes. The proportion of C37:4 alkenone to total C37 alkenones (%C37:4) and the relative abundance of archaeol to caldarchaeol (ACE) are promising salinity indices in lacustrine settings. Developing regional calibrations for both indicators is challenging due to limited datasets and a poor understanding of the factors that influence them. Here we present %C37:4 and ACE data collected from 55 lakes in mid-latitude Asia with a wide salinity range, to evaluate how well the two proxies can be correlated with salinity and to infer potential influencing factors. The %C37:4 values only show a weak negative correlation with salinity from all investigated lakes. The occurrence of C37:3 alkenone isomer and abnormal values in the alkenone C37/C38 ratio might signal species shifts or environmental factors that compromise the %C37:4-salinity relationship in our data set. Seasonal bias in alkenone production could further obscure this %C37:4-salinity relationship. A stronger relationship emerges after removing samples influenced by these factors: %C37:4 = − 8.56 ⁎ log 10 (salinity) + 80.6, r 2 = 0.62 , n = 37 ; or %C37:4 = − 13.46 ⁎ log 10 (salinity) + 101.48, with uncertainty in both variables considered. The ACE values show a strong positive correlation with salinity from all investigated lakes: ACE = 2.27 ⁎ 10 − 4 ⁎ salinity + 25.4 , r 2 = 0.75 , n = 68 ; or ACE = 1.86 ⁎ 10 − 4 ⁎ salinity + 38.1 , with uncertainty in both variables considered. However, substantial deviations of the ACE values in low salinity range (

中文翻译：

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亚洲中纬度湖泊烯酮和古菌醚盐度指标的评价

摘要 湖水盐度是反映湖泊水文状况的重要指标，是解读陆地古气候和古环境变化的关键。C37:4 烯酮与总 C37 烯酮 (%C37:4) 的比例以及古菌与钙藻醇 (ACE) 的相对丰度是湖泊环境中很有希望的盐度指数。由于数据集有限且对影响它们的因素了解不足，为这两个指标制定区域校准具有挑战性。在这里，我们展示了从亚洲中纬度 55 个湖泊中收集的 %C37:4 和 ACE 数据，这些湖泊的盐度范围很广，以评估这两个代理与盐度的相关程度并推断潜在的影响因素。%C37:4 值仅显示与所有调查湖泊的盐度呈微弱的负相关。C37的发生：3 烯酮异构体和烯酮 C37/C38 比率的异常值可能表明物种变化或环境因素会损害我们数据集中的 %C37:4 盐度关系。烯酮生产的季节性偏差可能会进一步掩盖这种 %C37:4-盐度关系。去除受以下因素影响的样本后出现更强的关系： %C37:4 = − 8.56 ⁎ log 10 (盐度) + 80.6, r 2 = 0.62 , n = 37 ; 或 %C37:4 = − 13.46 ⁎ log 10（盐度）+ 101.48，同时考虑两个变量的不确定性。ACE 值与所​​有调查湖泊的盐度呈强正相关：ACE = 2.27 ⁎ 10 − 4 ⁎ 盐度 + 25.4 , r 2 = 0.75 , n = 68 ；或 ACE = 1.86 ⁎ 10 − 4 ⁎ 盐度 + 38.1 ，考虑两个变量的不确定性。然而，低盐度范围内的 ACE 值有很大偏差（