Planktonic foraminifera stable isotopes and water column structure: Disentangling ecological signals
Planktonic foraminifera stable isotopes and water column structure: Disentangling ecological signals
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DOI：
10.1016/j.marmicro.2013.02.002
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发表时间：
2013-05-01
影响因子：
1.9
通讯作者：
O'Regan, Matthew
中科院分区：
文献类型：
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作者：
Birch, Heather;Coxall, Helen K.;O'Regan, Matthew
不同的碳和氧稳定同位素（三角洲C-13和三角洲O-18）分馏之间的浮游有孔虫测试方解石和海水有关的生态和生命阶段混淆重建古水柱温度和碳梯度的潜力。多物种分析和严格选择的测试大小是有用的方法来确定这些分馏过程，也被称为“生命效应”，在化石类群。然而，有足够的大小控制的数据集，在现代地面真实的方法所需的物种数量有限。在这里，我们报告三角洲C-13和三角洲O-18测量12种现代浮游有孔虫在一个范围内的14个严格限制的大小窗口，从热带印度洋的核心顶部样品。该数据集包括每个物种更多的测试尺寸窗口，特别是从最小的（可识别的）测试尺寸类，以及比以前尝试的更广泛的物种。我们使用的大小控制三角洲O-18方解石轨迹推断深度栖息地和计算物种特异性钙化温度。温度，然后用来限制物种特定的钙化深度沿着现代垂直温度分布在热带印度洋西部。通过覆盖当地水柱三角洲C-13（DIC）配置文件上的每种三角洲C-13方解石轨迹，我们估计，如果和何时（即在哪些测试尺寸）的南极有孔虫物种调查方法环境三角洲C-13（DIC）值。分析表明，在某些生命/生长阶段，所有物种的δ C-13与海水值之间存在显著的尺寸控制偏差，我们将其归因于（i）混合层光共生分类群在类似于300 μ m的测试中的代谢分馏。对于大多数物种来说，有一个大小窗口，这些影响似乎处于最低限度和/或平衡状态。一种名为“Bamboo”的小蜜蜂（
Differential carbon and oxygen stable isotope (delta C-13 and delta O-18) fractionation between planktonic foraminifera test calcite and sea water related to ecology and life stage confound the potential for reconstructing palaeo-water column temperature and carbon gradients. Multi-species analysis and strict selection of test sizes are useful methods for identifying these fractionation processes, also known as 'vital effects', in fossil taxa. However, there are a limited number of species with adequate size-controlled data sets, needed for ground truthing the approach in the modern. Here we report delta C-13 and delta O-18 measurements made on twelve species of modern planktonic foraminifera across a range of fourteen tightly constrained size windows from a tropical Indian Ocean core top sample. This data set includes more test size windows per species, especially from the smallest (identifiable) test size-classes, and a wider range of species than previously attempted. We use the size controlled delta O-18 calcite trajectories to infer depth habitats and calculate species-specific calcification temperatures. The temperatures are then used to constrain species-specific calcification depths along the modern vertical temperature profile in the western tropical Indian Ocean. By overlaying the per species delta C-13 calcite trajectories on local water column delta C-13(DIC) profiles, we estimate if and when (i.e. at which test sizes) the planktonic foraminifera species investigated approach ambient delta C-13(DIC) values. The profiling shows significant size-controlled delta C-13 deviation from seawater values in all species at some life/growth stage, which we attribute to (i) metabolic fractionation in tests similar to 300 mu m) of mixed layer photosymbiotic taxa. For most species there is a size-window where these effects appear to be at a minimum, and/or in balance. Exceptions are Globigerinita glutinata, a small (