Controls on shell Mg/Ca and Sr/Ca in cultured planktonic foraminiferan, Globigerinoides ruber (white)
Controls on shell Mg/Ca and Sr/Ca in cultured planktonic foraminiferan, Globigerinoides ruber (white)
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DOI：
10.1016/j.epsl.2008.06.026
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发表时间：
2008-09-15
影响因子：
5.3
通讯作者：
Erez, J.
中科院分区：
文献类型：
--
作者：
Kisakuerek, B.;Eisenhauer, A.;Erez, J.
Mg/Ca和Sr/Ca比值测定了一个单一物种的浮游有孔虫，Globigerinoides ruber（白色），收集自埃拉特湾，并在海水中培养在五个不同的盐度（32至44），五个温度（18至30摄氏度）和四个pH值（7.9至8.4）。培养的G. ruber（指数斜率为8 +/- 3%/℃）与先前发表的岩心顶部和沉积物捕集器校准结果一致。然而，Mg/Ca对盐度的依赖性（指数斜率为5 +/- 3%/psu）也很重要，应包括在校准方程中。为此，我们计算了G的校准方程。在95%的置信限内，Mg/Ca（mmol/mol）= exp[0.06（+/- 0.02）*S（psu）+ 0.08（+/- 0.02）*T（degrees C）2.8（+/- 1.0）]，R-2 = 0.95在环境海水pH值（8.1 ~ 8.3）下，pH值对Mg/Ca比值的影响可忽略不计。然而，当海水pH值低于8.0时，我们观察到对壳Mg/Ca的主导pH控制。Sr/Ca在G.红宝石与平均生长率呈显著正相关。据推测，在壳锶/钙在地质记录的变化的一部分是与有孔虫的生长速度的变化，作为对不断变化的环境条件的反应。(C)2008 Elsevier B. V.保留所有权利。
Mg/Ca and Sr/Ca ratios were determined on a single species of planktonic foraminiferan, Globigerinoides ruber (white), collected from the Gulf of Eilat and cultured in seawater at five different salinities (32 to 44), five temperatures (18 to 30 degrees C) and four pH values (7.9 to 8.4). The Mg/Ca-temperature calibration of cultured G. ruber (with an exponential slope of 8 +/- 3%/degrees C) agrees well with previously published calibrations from core-tops and sediment traps. However, the dependence of Mg/Ca on salinity (with an exponential slope of 5 +/- 3%/psu) is also significant and should be included in the calibration equation. With this purpose, we calculated a calibration equation for G. ruber dependent on both temperature and salinity within the 95% confidence limits:Mg/Ca(mmol/mol) = exp[0.06(+/- 0.02)*S(psu) + 0.08(+/- 0.02)*T(degrees C)2.8(+/- 1.0)], R-2 = 0.95The influence of pH on Mg/Ca ratios is negligible at ambient seawater pH (8.1 to 8.3). However, we observe a dominating pH control on shell Mg/Ca when the pH of seawater is lower than 8.0. Sr/Ca in G. ruber shows a significant positive correlation with average growth rate. Presumably, part of the variability in shell Sr/Ca in the geological record is linked to changes in growth rates of foraminifera as a response to changing environmental conditions. (C) 2008 Elsevier B.V. All rights reserved.