Effect of nitrate enrichment and diatoms on the bioavailability of Fe(III) oxyhydroxide colloids in seawater.
Effect of nitrate enrichment and diatoms on the bioavailability of Fe(III) oxyhydroxide colloids in seawater.
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DOI：
10.1016/j.chemosphere.2015.12.098
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发表时间：
2016-03
期刊：
影响因子：
8.8
通讯作者：
Fengjiao Liu;Bang-qin Huang;Shunxing Li;Feng-ying Zheng;Xuguang Huang
中科院分区：
文献类型：
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作者：
Fengjiao Liu;Bang-qin Huang;Shunxing Li;Feng-ying Zheng;Xuguang Huang
胶体铁羟基氧化物的光转化是海岸系统中生物可利用铁的重要来源。硅藻在沿海和上升流区的浮游植物群落中占主导地位。硅藻经常暴露于富营养化。我们研究了不同种类的硅藻，细胞密度，光照时间，和硝酸盐添加对Fe（III）羟基氧化物胶体在海水中的生物利用度的影响。随着光照时间的增加（1 ~ 4 h），不含硅藻的海水中溶解态总铁（DFe）与胶体铁氢氧化物的比值和Fe（II）与DFe的比值分别增加到24.3%和23.9%，中肋骨条藻为45.6%和30.2%，海链藻为44.3%和29.7%。首次证实了沿海硅藻自身（不包括藻类分泌的溶解有机物）对海水中铁的形态转化（包括Fe（III）羟基氧化物胶体的光诱导溶解和Fe（III）光还原为Fe（II））的光化学活性。中肋骨藻和海链藻对胶体氢氧化铁的光转化能力没有显着差异。硝酸盐的加入可以抑制海水中溶解态Fe（II）和DFe的光生作用。
The photoconversion of colloidal iron oxyhydroxides was a significant source of bioavailable iron in coastal systems. Diatoms dominate phytoplankton communities in coastal and upwelling regions. Diatoms are often exposed to eutrophication. We investigated the effects of different species of diatom, cell density, illumination period, and nitrate additions on the bioavailability of Fe(III) oxy-hydroxide colloids in seawaters. With the increase of illumination period from 1 to 4 h, the ratios of concentrations of total dissolved Fe (DFe) to colloidal iron oxyhydroxides and Fe(II) to DFe increased up to 24.3% and 23.9% for seawater without coastal diatoms, 45.6% and 30.2% forSkeletonema costatum, 44.3% and 29.7% forThalassiosira weissflogii, respectively. The photochemical activity of coastal diatoms themselves (excluding the dissolved organic matter secreted by algae) on the species transformation of iron in seawater (including the light-induced dissolution of Fe(III) oxyhydroxide colloids and the photo-reduction of Fe(III) into Fe(II)) was confirmed for the first time. There was no significant difference of the ability ofS. costatumandThalassiosira weissflogiion the photoconversion of colloidal iron oxyhydroxides. The photoproduction of dissolved Fe(II) and DFe in the seawater with or without diatoms could be depressed by the nitrate addition.