Calibration of Mg/Ca thermometry in planktonic foraminifera from a sediment trap time series
Calibration of Mg/Ca thermometry in planktonic foraminifera from a sediment trap time series
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DOI：
10.1029/2002pa000846
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发表时间：
2003-06-21
期刊：
影响因子：
--
通讯作者：
Conte, MH
中科院分区：
文献类型：
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作者：
Anand, P;Elderfield, H;Conte, MH
[1]对浮游有孔虫（G.红白色、G. ruber pink、G. sacculifer，囊囊藻G. Lactobatus，G. aequilateralis，O. universa，普通拟步行虫N. dutertrei、大斑拟步行虫P. inflata，鼓藻G. truncatulinoides，G. hirsuta和G. crassoformis）的时间序列来定义有孔虫Mg/Ca对钙化温度的敏感性。根据历史温度和盐度数据，通过比较有孔虫的δ（18）O与平衡方解石，估计了生境深度和钙化温度。当一起考虑时，除两种物质外，所有物质的Mg/Ca（mmol/ mol）均显示出与温度（T ℃）的显著（r = 0.93）关系，即Mg/Ca = 0.38（+/- 0.02）exp 0.090（+/- 0.003）T，相当于温度变化1 ℃，Mg/Ca变化9.0 +/- 0.3%。物种之间以及同一物种的不同粒度组分之间的校准存在微小差异。O. universa和G. aequilateralis的Mg/Ca比其他物种高，一般来说，所有物种的数据可以用相同的温度敏感性和序列O中的指前常数来描述。universa > G. aequilateralis与G. bulloides > G. ruber与G.与其他种接近的囊状体。这种方法在估计钙化温度时的准确度为+/- 1.2 ℃。9%的温度敏感度与已发表的培养和核心顶部校准研究相似，但与一些文献中的指前常数值存在差异。不同的清洗方法和人工制品的核心顶部溶解可能牵连，也许环境因素尚未了解。浮游有孔虫Mg/Ca温度估计可用于重建表面温度和混合温跃层温度（使用G。ruber pink、G. ruber白色、G. sacculifer、拟囊叶蝉N. dutertrei、斜孔P. obliquiloculata等）。一个单一的Mg测温方程的存在是有价值的灭绝的物种，虽然使用物种特有的方程，在统计上显着，提供更准确的评估Mg/Ca古温度。
[1] Paired Mg/Ca and delta(18)O measurements on planktonic foraminiferal species ( G. ruber white, G. ruber pink, G. sacculifer, G. conglobatus, G. aequilateralis, O. universa, N. dutertrei, P. obliquiloculata, G. inflata, G. truncatulinoides, G. hirsuta, and G. crassaformis) from a 6-year sediment trap time series in the Sargasso Sea were used to define the sensitivity of foraminiferal Mg/Ca to calcification temperature. Habitat depths and calcification temperatures were estimated from comparison of delta(18)O of foraminifera with equilibrium calcite, based on historical temperature and salinity data. When considered together, Mg/Ca ( mmol/ mol) of all species, except two, show a significant ( r = 0.93) relationship with temperature ( T degreesC) of the form Mg/Ca = 0.38 (+/- 0.02) exp 0.090 ( +/- 0.003) T, equivalent to a 9.0 +/- 0.3% change in Mg/Ca for a 1 degreesC change in temperature. Small differences exist in calibrations between species and between different size fractions of the same species. O. universa and G. aequilateralis have higher Mg/Ca than other species, and in general, data can be best described with the same temperature sensitivity for all species and pre-exponential constants in the sequence O. universa > G. aequilateralis approximate to G. bulloides > G. ruber approximate to G. sacculifer approximate to other species. This approach gives an accuracy of +/- 1.2 degreesC in the estimation of calcification temperature. The similar to9% sensitivity to temperature is similar to published studies from culture and core top calibrations, but differences exist from some literature values of pre-exponential constants. Different cleaning methodologies and artefacts of core top dissolution are probably implicated, and perhaps environmental factors yet understood. Planktonic foraminiferal Mg/Ca temperature estimates can be used for reconstructing surface temperatures and mixed and thermocline temperatures ( using G. ruber pink, G. ruber white, G. sacculifer, N. dutertrei, P. obliquiloculata, etc.). The existence of a single Mg thermometry equation is valuable for extinct species, although use of species-specific equations will, where statistically significant, provide more accurate evaluation of Mg/Ca paleotemperature.