A novel biomarker-based proxy for the spring phytoplankton bloom in Arctic and sub-arctic settings - HBI T25
A novel biomarker-based proxy for the spring phytoplankton bloom in Arctic and sub-arctic settings - HBI T25
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DOI：
10.1016/j.epsl.2019.06.038
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发表时间：
2019-10-01
影响因子：
5.3
通讯作者：
Husum, Katrine
中科院分区：
文献类型：
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作者：
Belt, Simon T.;Smik, Lukas;Husum, Katrine
春季浮游植物水华是现代中高纬度地区的一个特征，但在古记录中识别可能具有挑战性。在目前的研究中，我们调查了绝对和相对分布的两个ESTA衍生的三不饱和高度支化的类异戊二烯（HBI）脂质，其中至少有一个以前被认为是一个可能的代理生产区域的边缘冰区（MIZ）在极地地区。它们的分布在表层沉积物中的巴伦支海和邻近地区的一系列海洋学参数的比较的基础上，我们确定，通过主成分分析，两个HBIs和卫星派生的春季叶绿素a（叶绿素a）浓度的相对比例之间的强关联。此外，凝聚层次聚类的基础上，我们确定了两个集群的HBI生物标志物比率和春季叶绿素a与潜在的阈值生物标志物比率（称为HBI TR 25）的春季浮游植物水华。HBI TR 25的修改版本（即HBI T-25）提供了一个潜在的更直接的春季浮游植物水华的二进制措施。HBI TR 25和HBI T-25值在一系列短（跨越近几个世纪）和长（全新世）沉积物岩心从该地区的分析提供了一个初步的评估，这种新的代理在古记录的适用性。结果主要是一致的调查结果，从表面沉积物和其他代理为基础的重建，包括过去的海冰覆盖，这是众所周知的影响该地区的初级生产的估计。事实上，我们认为，新的HBI T-25浮游植物水华代理也可能是一个重要的新工具，用于表征MIZ的古记录，特别是当使用的同时，完善的海冰代理，如IP 25和PIP 25。尽管这项研究在很大程度上是经验性的，但我们也为观察到的生物标志物比率与叶绿素a的关系提供了一种可能的解释。因此，先前的实验室调查表明，本文分析的相同的两种HBIs在其可能的来源（即，Ringosolenia setigera）中的分布受到培养温度和生长速率的强烈影响。然而，要确认我们的研究结果的普遍性以及HBI T-25和春季浮游植物水华之间的因果关系，还需要在未来进行进一步的实验室和实地研究。(C)2019作者（S）出版社：Elsevier B. V.
The spring phytoplankton bloom is a characteristic feature of mid-high latitudes in modern times, but can be challenging to identify in palaeo records. In the current study, we investigated the absolute and relative distributions of two diatom-derived tri-unsaturated highly branched isoprenoid (HBI) lipids, at least one of which has previously been suggested to be a possible proxy for the productive region of the marginal ice zone (MIZ) in the Polar Regions. Based on a comparison of their distributions in surface sediments from the Barents Sea and neighbouring regions with a range of oceanographic parameters, we identify, via principal component analysis, a strong association between the relative proportion of the two HBIs and satellite-derived spring chlorophyll a (chl a) concentration. Further, based on agglomerative hierarchical clustering, we identify two clusters of HBI biomarker ratios and spring chl a together with a potential threshold biomarker ratio (termed HBI TR25) for the spring phytoplankton bloom. A modified version of HBI TR25 (i.e. HBI T-25) provides a potentially more straightforward binary measure of the spring phytoplankton bloom. Analysis of HBI TR25 and HBI T-25 values in a series of short (spanning recent centuries) and long (Holocene) sediment cores from the region provides an initial evaluation of the applicability of this novel proxy in the palaeo record. Outcomes are mainly consistent with the findings from the surface sediments and with other proxy-based reconstructions, including estimates of past sea ice cover, which is well-known to influence primary production in the region. Indeed, we suggest that the new HBI T-25 phytoplankton bloom proxy may also represent an important new tool for characterising the MIZ in palaeo records, especially when used alongside well-established sea ice proxies, such as IP25 and PIP25. Despite the largely empirical nature of the study, we also provide a possible explanation for the observed biomarker ratio-chl a relationship. Thus, a previous laboratory investigation showed that the distributions of the same two HBIs analysed herein in their likely source (viz. Rhizosolenia setigera) was strongly influenced by culture temperature and growth rate. Confirmation of the generality of our findings and of the causal relationship between HBI T-25 and the spring phytoplankton bloom will, however, require further laboratory- and field-based studies in the future. (C) 2019 The Author(s). Published by Elsevier B.V.