The Black Sea underwent dramatic changes in salinity from the last glacial maximum to Holocene as it evolved from a large inland lake to become a part of the global ocean due to post-glacial sea level rise. However, the detailed history of the re-connection of the Black Sea to the Mediterranean and the resulting Black Sea salinity variations have been heavily debated. We take advantage of our recent study on alkenones from phylogenetically classified haptophyte groups and their association with variable salinity levels in modern environments to reconstruct detailed salinity changes in the Black Sea over the past 16,000 years. We report the first discovery and documentation of alkenones from Group I Isochrysidales in relation to past salinity changes in the Unit III sediment. Our data indicate that the Black Sea surface salinity gradually increased from near fresh at ∼16 ka (∼1-2 psu) to oligohaline (∼ 5-6 psu) at ∼ 9.4 ka, the time of initial marine inflow, suggesting a negative regional hydrological balance. Although the IMI (initial marine inflow) occurred at 9.4 ka, the relatively low surface water salinity levels persisted to the beginning of sapropel formation at 7.6 ka, suggesting a strongly positive regional hydrological balance. Alkenone profiles also indicate a period of significantly reduced salinity between 3.5 and 1.6 ka, differing from the previous proposed peak salinity at 2.7 ka based on alkenone hydrogen isotope values. We demonstrate that the mismatch originates from the predominance of previously unidentified Group II Isochrysidales over E. huxleyi during this time interval, and when species-specific hydrogen isotopic fractionation of alkenones is taken into consideration, the isotope-inferred salinity between 3.5 and 1.6 ka is consistent with our proposal. Our new assessment of the Black Sea salinity evolution since the last glacial shows broad agreement with other regional records and provides a new basis for evaluating the impact of regional hydrological changes on Neolithic human migrations to Europe.

黑海经历了从最后一次冰川期到全新世的盐度变化，由于冰川后海平面上升，黑海从一个大的内陆湖泊演变成为全球海洋的一部分。但是，关于黑海与地中海重新连接的详细历史以及由此产生的黑海盐度变化已经引起了激烈的争论。我们利用最近对系统发育分类触角植物类烯酮及其与现代环境中不同盐度水平的关联的研究来重建过去16,000年黑海中详细的盐度变化。我们报告了第一类等位线虫烯酮与第三单元沉积物中过去盐度变化有关的首次发现和文献记载。我们的数据表明，黑海的盐度从最初的约16 ka（〜1-2 psu）的近新鲜水逐渐增加到最初的海洋流入时间约9.4 ka的寡盐盐（〜5-6 psu），表明该区域为负值。水文平衡。尽管IMI（初始海洋流入量）发生在9.4 ka，但相对较低的地表水盐度水平一直持续到7.6 ka的腐腐土形成，表明区域水文平衡非常强。基于烯酮氢同位素值，烯酮的分布图还表明了盐度在3.5和1.6 ka之间显着降低的时期，这不同于先前提出的在2.7 ka时的盐度峰值。我们证明，这种失配源于先前未鉴定的第二类等轴虫的优势。初始海洋流入的时间，表明区域水文平衡为负值。尽管IMI（初始海洋流入量）发生在9.4 ka，但相对较低的地表水盐度水平一直持续到7.6 ka的腐腐土形成，表明区域水文平衡非常强。基于烯酮氢同位素值，烯酮的分布图还表明了盐度在3.5和1.6 ka之间显着降低的时期，这不同于先前提出的在2.7 ka时的盐度峰值。我们证明，这种失配源于先前未鉴定的第二类等轴虫的优势。初始海洋流入的时间，表明区域水文平衡为负值。尽管IMI（初始海洋流入量）发生在9.4 ka，但相对较低的地表水盐度水平一直持续到7.6 ka的腐腐土形成，表明区域水文平衡非常强。烯酮的分布还表明，盐度在3.5和1.6 ka之间显着降低，这与之前基于烯酮氢同位素值提出的在2.7 ka时出现的峰值盐度不同。我们证明，这种失配源于先前未鉴定的第二类等轴虫的优势。相对较低的地表水盐度水平一直持续到7.6 ka腐腐菌形成的开始，这表明该地区的水文平衡非常强。烯酮的分布还表明，盐度在3.5和1.6 ka之间显着降低，这与之前基于烯酮氢同位素值提出的在2.7 ka时出现的峰值盐度不同。我们证明，这种失配源于先前未鉴定的第二类等轴虫的优势。相对较低的地表水盐度水平一直持续到7.6 ka腐腐菌形成的开始，这表明该地区的水文平衡非常强。烯酮的分布还表明，盐度在3.5和1.6 ka之间显着降低，这与之前基于烯酮氢同位素值提出的在2.7 ka时出现的峰值盐度不同。我们证明，这种失配源于先前未鉴定的第二类等轴虫的优势。E.贺胥此时间间隔期间，并且当烯酮的物种特异性氢同位素分馏考虑到，3.5和1.6之间か同位素推断盐度是我们的建议相一致。自上次冰川以来，我们对黑海盐度演变的新评估显示出与其他区域记录的广泛共识，并为评估区域水文学变化对新石器时代人类向欧洲迁移的影响提供了新的依据。