Indirect control of the intracellular nitrate pool of intertidal sediment by the polychaete Hediste diversicolor
Indirect control of the intracellular nitrate pool of intertidal sediment by the polychaete Hediste diversicolor
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DOI：
10.3354/meps09464
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发表时间：
2012-01-01
影响因子：
2.5
通讯作者：
Stief, Peter
中科院分区：
文献类型：
--
作者：
Heisterkamp, Ines M.;Kamp, Anja;Stief, Peter
在德国瓦登海的一个潮间带，发现了一个巨大的细胞内硝酸盐沉积池，远远超过了自由溶解在孔隙水中的硝酸盐池。细胞内硝酸盐甚至存在于缺氧沉积物层的深处，在那里它可能用于厌氧呼吸过程。通过室内实验研究了细胞内硝酸盐库的来源和一些生态控制因素。泥沙微环境的建立有和没有丰富的多毛体Hediste diversicolor，已知刺激硝酸盐生产的微生物硝化作用的沉积物。在附加处理中添加氨以模拟蠕虫的氨排泄，或添加丙烯基硫脲（ATU）以抑制沉积物细菌的硝化作用。异色h和铵增加，ATU减少沉积物胞内硝酸盐库。孔隙水硝酸盐微传感器分析结果表明，蚯蚓和铵盐的加入对细菌硝化作用有促进作用。因此，硝化作用为沉积物胞内硝酸盐库提供了重要的硝酸盐供应。细胞内硝酸盐的垂直分布与光色素叶绿素a和岩藻黄素的垂直分布一致，强烈表明硅藻是主要的硝酸盐储存生物。因此，细胞内硝酸盐的形成是由系统发育上相距遥远的生物群的相互作用刺激的：蠕虫通过以颗粒有机物为食、排泄铵并使沉积物氧化来增强硝化作用；细菌在含氧沉积层中将铵氧化为硝酸盐；硅藻在细胞内储存硝酸盐。
In an intertidal flat of the German Wadden Sea, a large sedimentary pool of intracellular nitrate was discovered that by far exceeded the pool of nitrate that was freely dissolved in the porewater. Intracellular nitrate was even present deep in anoxic sediment layers where it might be used for anaerobic respiration processes. The origin and some of the ecological controls of this intracellular nitrate pool were investigated in a laboratory experiment. Sediment microcosms were set up with and without the abundant polychaete Hediste diversicolor that is known to stimulate nitrate production by microbial nitrification in the sediment. Additional treatments were amended with ammonium to mimic ammonium excretion by the worms or with allylthiourea (ATU) to inhibit nitrification by sediment bacteria. H. diversicolor and ammonium increased, while ATU decreased the intracellular nitrate pool in the sediment. Microsensor profiles of porewater nitrate showed that bacterial nitrification was enhanced by worms and ammonium addition. Thus, nitrification formed an important nitrate supply for the intracellular nitrate pool in the sediment. The vertical distribution of intracellular nitrate matched that of the photopigments chlorophyll a and fucoxanthin, strongly suggesting that diatoms were the main nitrate-storing organisms. Intracellular nitrate formation is thus stimulated by the interaction of phylogenetically distant groups of organisms: worms enhance nitrification by feeding on particulate organic matter, excreting ammonium and oxygenating the sediment; bacteria oxidise ammonium to nitrate in oxic sediment layers; and diatoms store nitrate intracellularly.