Mg isotopes in chlorophyll-a and coccoliths of cultured coccolithophores (Emiliania huxleyi) by MC-ICP-MS
Mg isotopes in chlorophyll-a and coccoliths of cultured coccolithophores (Emiliania huxleyi) by MC-ICP-MS
复制标题
DOI：
10.1016/j.marchem.2010.07.004
复制
发表时间：
2010-10
期刊：
影响因子：
3
通讯作者：
K. Ra;H. Kitagawa;Y. Shiraiwa
中科院分区：
文献类型：
--
作者：
K. Ra;H. Kitagawa;Y. Shiraiwa
我们提出的镁同位素组成和分馏叶绿素a和颗石培养的颗石藻生长在三个不同的温度。在10 ~ 25°C的温度范围内，叶绿素a和球石δ 26 Mg值的总体变化分别为1.91‰和1.37‰。叶绿素a和球孢子体E.相对于培养基，huxleyi的较重同位素略微耗尽。球孢子相对于培养基的同位素分馏比叶绿素a大。叶绿素a和颗石体的δ 26 Mg对温度的依赖性分别为0.10‰/°C和0.06-0.10‰/°C。稳定期叶绿素a和颗石体的δ 26 Mg值比指数期晚期的δ 26 Mg值轻得多。球形藻的δ ~（26）Mg值与叶绿素a值之间存在显著的相关性，表明球形藻从培养液中获取Mg的过程中存在一个生长速率依赖性步骤。此外，叶绿素a和球石体的ε 26 Mg与生长速率呈正相关，表明Mg同位素分馏受生长速率的影响。对颗石藻中Mg同位素的进一步研究可能为颗石藻的生产力提供有用的工具，特别是关于颗石藻的生长速率。
We present the Mg isotope composition and fractionation of chlorophyll-a and coccoliths using cultured coccolithophores that were grown at three different temperatures. The overall variations in δ26Mg values over a range of temperatures from 10 to 25°C were 1.91‰ and 1.37‰ for chlorophyll-a and coccoliths, respectively. Chlorophyll-a and coccoliths of E. huxleyi were slightly depleted in heavier isotopes relative to the culture medium. The isotope fractionation of coccoliths relative to culture medium was larger than that of chlorophyll-a. δ26Mg of chlorophyll-a and coccoliths showed temperature dependence of about 0.10‰/°C for chlorophyll-a and 0.06–0.10‰/°C for coccoliths. δ26Mg values in chlorophyll-a and coccoliths from the stationary phase were isotopically much lighter than those from the late exponential phase. There was a significant correlation between the δ26Mg values of coccoliths and chlorophyll-a, suggesting that a growth rate-dependent step occurs during the initial acquisition of Mg from the culture medium. Additionally, a positive relationship was observed between ε26Mg of either chlorophyll-a or coccoliths and the growth rates, indicating that Mg isotopic fractionation could be influenced by the growth rate. Further Mg isotope studies in coccoliths may provide a useful tool for coccolithophores productivity, especially with respect to the coccoliths' growth rate.