Change in the concentrations of iron in different size fractions during growth of the oceanic diatom Chaetoceros sp.: importance of small colloidal iron
Change in the concentrations of iron in different size fractions during growth of the oceanic diatom Chaetoceros sp.: importance of small colloidal iron
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海洋硅藻角毛藻生长过程中不同尺寸部分铁浓度的变化：小胶体铁的重要性
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. Takeda
中科院分区：
文献类型：
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作者：
J. Nishioka;S. Takeda
摘要：通过实验室培养实验研究了海洋硅藻 Chaetoceros sp. 生长过程中尺寸分级 Fe 浓度的变化。 Fe浓度按三个尺寸部分进行估计：大的不稳定颗粒（>0.2μm）、小胶体颗粒（0.2μm至200kDa）和可溶性物质（<200kDa）。在添加 FeCl3 溶液后 4 天内，不含硅藻细胞的营养富集过滤海水培养基中的尺寸分级 Fe 浓度变得稳定。白色荧光管以 14 小时光照：10 小时黑暗循环进行光照射并没有显着改变尺寸分级 Fe 的浓度。对于浮游植物培养实验，将缺铁的硅藻细胞接种到添加 FeCl3 后老化 19 天的营养丰富的培养基中。随着硅藻细胞的生长，在 7 天的培养过程中，总酸不稳定 Fe 浓度从 0.60 nM 降至 0.46 nM。然而，只有小胶体颗粒的浓度出现了明显的下降；其他尺寸部分的浓度保持相对恒定。尽管培养基仍然含有足够量的大不稳定颗粒和可溶性物质铁，但一旦小胶体颗粒铁被耗尽，硅藻细胞似乎铁含量有限。这些结果表明，小胶体颗粒部分中的 Fe 是硅藻 Chaetoceros sp 生长过程中最具动态的尺寸部分。此外，为了更好地了解海洋中的铁动态，我们必须考虑浮游植物生长对小胶体铁的影响（通常包含在溶解的铁部分（<0.2μm）中）。
Abstract Laboratory culture experiments were performed to study the changes in size-fractionated Fe concentrations during the growth of the oceanic diatom Chaetoceros sp. Fe concentration was estimated for three size fractions: large labile particles (>0.2 μm), small colloidal particles (0.2 μm to 200 kDa) and soluble species (<200 kDa). The size-fractionated Fe concentration in the nutrient-enriched filtered seawater medium without diatom cells became stable within 4 d after the spike of FeCl3 solution. Light irradiation by white fluorescent tubes with a 14 h light:10 h dark cycle did not significantly alter concentrations of the size-fractionated Fe. For the phytoplankton culture experiment, Fe-starved diatom cells were inoculated into the nutrient-enriched media aged for 19 d after the addition of FeCl3. With the growth of diatom cells, total acid-labile Fe concentrations decreased from 0.60 to 0.46 nM during 7 d of incubation. However, only the concentration of the small colloidal particles showed a significant decrease; the concentration of the other size fractions remained relatively constant. Although the media still contained sufficient amounts Fe as large labile particles and soluble species, diatom cells appeared to be Fe-limited once Fe as small colloidal particles had been used up. These results suggest that Fe in the small colloidal particle fraction was the most dynamic size fraction during the growth of the diatom Chaetoceros sp. In addition, to better understand Fe dynamics in the ocean, we must consider the influence of phytoplankton growth on small colloidal Fe [which is typically included in the dissolved Fe fraction (<0.2 μm)].