Microscale alkenone heterogeneity and replicability of ultra-high-resolution temperature records from marine sediments

作者：Jannis Viola, Lars Woermer, Kai‐Uwe Hinrichs, Thomas Laepple · 发表于：Climate of the past · 年份：2026 · DOI：10.5194/cp-22-1023-2026 · 被引用次数：1 · 研究领域：Geology and Paleoclimatology Research、Archaeology and ancient environmental studies、Geological formations and processes

Abstract. The alkenone-derived UK37 proxy is crucial for the reconstruction of past sea surface temperatures in marine sedimentary archives. Recent advances in mass spectrometry imaging (MSI) now allow to measure alkenone abundance at the micrometer scale. Such an approach can theoretically provide proxy records as highly resolved as observational records and hold the promise of continuously reconstructing climate variability from subseasonal or interannual to centennial and millennial timescales. However, due to processes occurring during and after deposition, as well as during sampling and measurement, it is unclear how much climate signal is preserved in the proxy signal at these small spatial scales. Here, we investigated this question on sediment records from the Santa Barbara Basin (SBB), off California. We performed replicated MSI measurements on sediments with varying degrees of lamination to analyze the spatial structure and spatial reproducibility of the alkenone signal. We find that alkenone distributions are spatially heterogeneous even within laminae but exhibit small scale clustering over the range of ~0.5–1 mm. Measurements along laminated horizons show longer ranges of similarity and less overall variability compared to measurements across depth. Signal to noise ratios (SNR), the amount of shared variance between proxy records derived from the replicates across varying sediment conditions range from ~1 SNR at interannual resolution to ~3 SNR at subdecadal time...