Earth and Environmental Systems, Indiana State University, Terre Haute, IN, 47808, USA.
Integrative Oceanography Division, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA, 92093-0218, USA.
Sci Rep. 2018 Jun 21;8(1):9456. doi: 10.1038/s41598-018-27793-4.
The negative consequences of fossil fuel burning for the oceans will likely include warming, acidification and deoxygenation, yet predicting future deoxygenation is difficult. Sensitive proxies for oxygen concentrations in ancient deep-ocean bottom-waters are needed to learn from patterns of marine deoxygenation during global warming conditions in the geological past. Understanding of past oxygenation effects related to climate change will better inform us about future patterns of deoxygenation. Here we describe a new, quantitative biological proxy for determining ocean paleo-oxygen concentrations: the surface area of pores (used for gas exchange) in the tests of deep-sea benthic foraminifera collected alive from 22 locations (water depths: 400 to 4100 m) at oxygen levels ranging from ~ 2 to ~ 277 μmol/l. This new proxy is based on species that are widely distributed geographically, bathymetrically and chronologically, and therefore should have broad applications. Our calibration demonstrates a strong, negative logarithmic correlation between bottom-water oxygen concentrations and pore surface area, indicating that pore surface area of fossil epifaunal benthic foraminifera can be used to reconstruct past changes in deep ocean oxygen and redox levels.
燃烧化石燃料对海洋造成的负面影响可能包括海水升温、酸化和脱氧，然而预测未来脱氧情况十分困难。我们需要敏感的古深海底层水氧浓度替代指标，以便从地质历史时期全球变暖条件下海洋脱氧的模式中学习。了解与气候变化相关的过去的富氧效应将使我们更好地了解未来脱氧的模式。在这里，我们描述了一种新的、定量的生物指标，用于确定海洋古氧浓度：从 22 个地点（水深：400 至 4100 米）采集的、活着的深海底栖有孔虫的壳上的孔隙表面积（用于气体交换），这些有孔虫的氧含量范围从2 到277 μmol/l。这个新的指标基于广泛分布在地理、水深和时间上的物种，因此应该有广泛的应用。我们的标定表明，底层水氧浓度与孔隙表面积之间存在强烈的负对数相关性，表明化石外附生底栖有孔虫的孔隙表面积可用于重建深海氧气和氧化还原水平的过去变化。
