Characteristics of alkenones synthesized by a bloom of Emiliania huxleyi in the Bering Sea
Characteristics of alkenones synthesized by a bloom of Emiliania huxleyi in the Bering Sea
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DOI：
10.1016/s0016-7037(02)01318-2
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发表时间：
2003-04-01
影响因子：
5
通讯作者：
Nakatani, T
中科院分区：
文献类型：
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作者：
Harada, N;Shin, KH;Nakatani, T
我们调查了2000年白令海东部的一次水华Emiliania huxleyi产生的烯酮的特征。在北纬57度至63度之间的表层沃茨中检测到了烯酮，这里磷酸盐浓度低，铵/硝酸盐比率高。总烯酮含量（C-37：2，C-37：3，和C-37：4）范围从22.0至349微克（-1）悬浮颗粒和从0.109至1.42微克9 1在表层沉积物。这表明，在地表水中合成的颗粒状烯酮大部分在水柱内和/或在白令大陆架的水-沉积物界面处迅速降解。C-37：3烯酮稳定碳同位素组成（δ（13）C）的变化不能仅用表层水[CO2（aq）]的变化来解释，还取决于E. huxleyi。用三个方程将烯酮不饱和指数（U-37（K '））转化为烯酮“温度”（Prahl等人，1988; Sikes等人，1997; Miiller等人，1998）; Sikes等人（1997）方程与东白令海实测海表温度（SST）的相关性最好。然而，一些温度估计由赛克斯等人。根据U-37（K '）得出的公式与观测到的SST不同，这可能是因为在对数生长阶段烯酮合成速率变化迅速，或在营养物有限时烯酮合成速率较低。由表层沉积物中U-37（K '）估算的温度（6.8 - 8.2 ℃）与9月观测到的SST（7- 8 ℃）相匹配，但与4 - 5 ℃的年平均SST不同，这表明白令海东部的大部分烯酮是在有限的时期合成的，例如9月。C-37：3烯酮占总烯酮的比例（称为C-37：4%）的相对量很高，范围为18.3%至41.4%。低盐度水（
We investigated the characteristics of the alkenones produced by a bloom of Emiliania huxleyi in the eastern Bering Sea in 2000. Alkenones were detected in surface waters between 57degreesN and 63degreesN, where phosphate concentrations were low and the ammonium/nitrate ratio was high. The total alkenone content (C-37:2, C-37:3, and C-37:4) ranged from 22.0 to 349 mug g(-1) in suspended particles and from 0.109 to 1.42 mug 9 1 in surface sediments. This suggests that a large proportion of the particulate alkenones synthesized in the surface water rapidly degraded within the water column and/or at the water-sediment interface of the Bering Shelf. The change in the stable carbon isotopic composition (delta(13)C) of C-37:3 alkenone could not be explained only by variation in [CO2(aq)] in the surface water but also depended on the growth rate of E. huxleyi. The alkenone unsaturation index (U-37(K')) was converted into an alkenone "temperature" with three equations (Prahl et al., 1988; Sikes et al., 1997; Miiller et al., 1998); Sikes et al.'s (1997) equation gave the best correlation with the observed sea surface temperature (SST) in the eastern Bering Sea. However, some temperatures estimated by Sikes et al.'s (1997) equation from the U-37(K') varied from the observed SST, possibly because of the rapidly changing rate of alkenone synthesis in the logarithmic growth stage or the low rate of alkenone synthesis when nutrients were limiting. Temperatures estimated from U-37(K') in the surface sediments (6.8 - 8.2degreesC) matched the observed SST in September (7-8degreesC) but differed from the annual average SST of 4 to 5degreesC, suggesting that most of the alkenone in the eastern Bering Sea was synthesized during limited periods, for instance, in September. The relative amounts of C-37:3 alkenone as proportions of the total alkenones (referred to as C-37:4%) were high, ranging from 18.3 to 41.4%. Low-salinity water (