Lipid biomarkers archived in marine sediments include widely applied proxies to reconstruct sea surface temperature (SST). Two prominent groups of SST sensitive biomarkers are long‐chain alkenones from haptophyte algae and glycerol dibiphytanyl glycerol tetraethers (GDGTs) from planktonic Thaumarchaeota. The corresponding proxies, and TEX₈₆, respectively, are strongly correlated with mean annual SST. However, culture experiments suggest that other factors such as nutrients could also influence the proxy signals. We created monthly resolved records of molecular SST proxies via mass spectrometry imaging at 200‐μm resolution in varved sediments from Santa Barbara Basin deposited between 1984 and 2009. Direct comparison to coeval water column data determined at seasonal resolution allows new mechanistic insights into environmental parameters influencing proxy signal formation. The responds sensitively to SST variations, while also being influenced by seasonal variations in nutrient concentrations. Surface water nitrate concentrations above or below ~2 μmol/L are associated with values that overestimate or underestimate actual SST, respectively. Distributions of the two major GDGTs, expressed as the Crenarchaeol‐Caldarchaeol‐Tetraether index (CCaT), are highly similar to those of the minor cycloalkylated compounds GDGT‐1 to GDGT‐3, presented as the corresponding ring index. The CCaT is correlated with subsurface chemical properties, which are controlled by interannual variations in upwelling intensity linked to dynamics of the California Current System. This relationship is attributed to the impact of nutrients on thaumarchaeal growth rates and GDGT cyclization. The coupling of CCaT to SST was weak but enhanced for temperatures averaged across the upper 100 m of the water column.

中文翻译：

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通过比较南加利福尼亚州圣塔芭芭拉盆地的水底数据和工具的年年解析沉积记录，对分子代理进行机械分析。

沉积在海洋沉积物中的脂质生物标志物包括广泛用于重建海面温度（SST）的代理。SST敏感生物标志物的两个主要组是来自触藻类藻类的长链烯酮和来自浮游Thaumarchaeota的甘油二双二十烷酰基甘油四醚（GDGT）。相应的代理，以及TEX ₈₆分别与年平均SST密切相关。但是，培养实验表明，其他因素（例如营养素）也可能影响代用信号。我们通过质谱成像在1984年至2009年之间沉积的圣塔芭芭拉盆地的脉状沉积物中以200 µm的分辨率创建了分子SST代理的月度解析记录。直接与以季节分辨率确定的同龄水柱数据进行比较，可以提供新的机制洞察力，以了解影响环境的参数代理信号形成。在同时受到养分浓度季节变化影响到SST变化敏感响应。高于或低于〜2μmol/ L的地表水中硝酸盐浓度与分别高估或低估实际SST的值。两种主要的GDGT的分布表示为Crenarchaeol-Caldarchaeol-Tetraether指数（CCaT），与较小的环烷基化化合物GDGT-1至GDGT-3的分布高度相似，以相应的环指数表示。CCaT与地下化学性质相关，该化学性质由上升强度的年际变化控制，该上升强度与“加州现行系统”的动力学有关。这种关系归因于养分对拟南芥生长速率和GDGT环化的影响。CCaT与SST的耦合较弱，但对于水柱上部100 m的平均温度而言，耦合作用增强。