Trace element composition of modern planktic foraminifera from an oxygen minimum zone: Potential proxies for an enigmatic environment
Trace element composition of modern planktic foraminifera from an oxygen minimum zone: Potential proxies for an enigmatic environment
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DOI：
10.3389/fmars.2023.1145756
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
C. V. Davis;S. Doherty;J. Fehrenbacher;K. Wishner
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文献类型：
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作者：
C. V. Davis;S. Doherty;J. Fehrenbacher;K. Wishner
氧气有限的海洋环境，如氧气最低区，对全球营养循环和垂直栖息地的可用性具有深远的重要意义。虽然可以理解，氧气最小区的范围和强度是对气候的反应，有限的一套可行的代理低氧远洋环境继续构成一个真实的障碍，古气候的解释。在这里，我们调查代理潜在的微量元素（镁，锰，锌，锶）的数组，钙比从Globorotaloides hexagonus，一个热带特有的温带有孔虫通过温带氧气最低区的外壳。提出了一个种属特异性的Mg/Ca与温度的关系，用于定量重建氧最小带古温度。Mn/Ca和Zn/Ca比值均随氧浓度的变化而变化，可用于G. hexagonus栖息地，其中主要信号可以从成岩叠加中区分出来。最后，一个强大的Sr/Ca比和溶解氧之间的相关性表明，作为一个指标的氧最小区强度，可能通过有孔虫的生长速率Sr的作用。这些相对传统的微量元素的比例在一个氧最小区物种的壳的分析有巨大的潜力，以促进多代理重建从这个谜一样的环境。
Oxygen limited marine environments, such as oxygen minimum zones, are of profound importance for global nutrient cycling and vertical habitat availability. While it is understood that the extent and intensity of oxygen minimum zones are responsive to climate, the limited suite of viable proxies for low oxygen pelagic environments continues to pose a real barrier for paleoclimate interpretations. Here we investigate the proxy potential of an array of trace element (Mg, Mn, Zn, and Sr) to Ca ratios from the shells of Globorotaloides hexagonus, a planktic foraminifer endemic to tropical through temperate oxygen minimum zones. A species-specific relationship between Mg/Ca and temperature is proposed for quantitative reconstruction of oxygen minimum zone paleotemperatures. Both Mn/Ca and Zn/Ca ratios vary with oxygen concentration and could be useful for reconstructing G. hexagonus habitat where the primary signal can be d\istinguished from diagenetic overprinting. Finally, a robust correlation between Sr/Ca ratios and dissolved oxygen demonstrates a role for Sr as an indicator of oxygen minimum zone intensity, potentially via foraminiferal growth rate. The analysis of these relatively conventional trace element ratios in the shells of an oxygen minimum zone species has tremendous potential to facilitate multiproxy reconstructions from this enigmatic environment.