Molecular and Isotopic Coupling between Pelagic and Benthic Carbon Cycling-a Proof of Concept

有机物在水柱中下落与在海底沉积物中积累之间的定量关系是理解海洋有机化学的主要挑战之一。虽然海洋上层生物产生的有机物将海洋化学特征转移到沉积物中，但表层沉积物中的有机物看起来非常不同：它的成分不同，显然富含陆地生物标志物，放射性碳年龄表明旧的改造物质的输入。在这项研究中，斯基德韦海洋学研究所的科学家将使用沉积物捕集器和底层沉积物中收集的有机物配对样本，推断在下沉有机物积累在海底之前从下沉有机物中降解（从而被去除）的有机物的化学特性。首先，他们将确定来自各种海洋环境的沉积物圈闭/沉积物对中关键生物标志物的分子和同位素特征。其次，他们将利用分子和同位素分布来限制在水柱中和沉积物-水界面上降解的大量有机碳的性质，有机碳的损失决定了沉积物中可以积累和保存在沉积记录中的有机碳的性质。

ABSTRACTOCE-9911678The quantitative relationship between organic matter falling through the water column and that accumulating in seafloor sediments presents one of the major challenges to understanding the organic chemistry of the ocean. Although organic matter produced biologically in the upper ocean transfers a marine chemical signature to the sediments, the organic matter in surface sediments looks very different: it is compositionally different, apparently enriched with terrestrial biomarkers and having radiocarbon ages suggesting input of old reworked material. In this study, scientists at the Skidaway Institute of Oceanography will use paired samples of organic matter collected in sediment traps and underlying sediments to deduce the chemical character of the organic matter that is degraded (and thus removed) from sinking organic matter before it accumulates on the seafloor. First, they will determine the molecular and isotopic character of key biomarkers in sediment trap/sediment pairs from a variety of oceanic environments. Secondly, they will use molecular and isotopic distributions to constrain the character of the bulk of organic carbon that is degraded in the water column and at the sediment-water interface, the loss of which determines the nature of the organic carbon that can be accumulated in sediments and preserved in the sedimentary record.