Production of 15N-depleted biomass during cyanobacterial N2-fixation at high Fe concentrations
Production of 15N-depleted biomass during cyanobacterial N2-fixation at high Fe concentrations
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DOI：
10.1029/2007jg000651
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发表时间：
2008-09
影响因子：
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通讯作者：
A. Zerkle;C. Junium;D. Canfield;C. House
中科院分区：
文献类型：
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作者：
A. Zerkle;C. Junium;D. Canfield;C. House
[1] 在这项研究中，我们研究了不同的 Fe、Mo 和 P 浓度对蓝藻鱼腥藻固定 N 2 过程中 δ 15 N 分馏的影响。我们表明，当在富含 Fe 的培养基 ([Fe] > 50 nM) 中生长时，该生物体在 δ 15 N 中产生的生物量比在 Fe 有限的培养基 ([Fe] < 50 nM) 中生长时低 3%。将我们的数据与之前固定 N 2 的蓝藻中 δ 15 N 的测量值进行汇编，揭示了在较高 Fe 浓度下产生更多 15 N 贫化生物质的总体趋势。我们在太古代和一些显生宙沉积物中保存的负 δ 15 N 值的背景下讨论了我们的结果，这通常归因于在营养动态波动期间通过 N 2 固定（以及潜在的 NH4 再生）产生具有低 δ 15 N 的海洋有机物。我们认为，在广泛的海洋缺氧期间，提高铁的可用性可以进一步刺激固氮生物体产生 15 N 贫化生物量，从而有助于同位素记录。
[1] In this study we examine the effects of varying Fe, Mo, and P concentrations on δ 15 N fractionation during N 2 fixation in the cyanobacterium Anabaena variabilis. We show that when grown in Fe-enriched media ([Fe] > 50 nM), this organism produces biomass up to 3%o lower in δ 15 N than when grown in Fe-limited media ([Fe] < 50 nM). A compilation of our data with previous measurements of δ 15 N in N 2 -fixing cyanobacteria reveals a general trend toward the production of more 15 N-depleted biomass at higher Fe concentrations. We discuss our results in the context of negative δ 15 N values preserved in Archean and some Phanerozoic sediments, generally attributed to the production of marine organic matter with low δ 15 N by N 2 fixation (and potentially NH4 regeneration) during periods of fluctuating nutrient dynamics. We suggest that enhanced Fe availability during periods of widespread ocean anoxia can further stimulate the production of 15 N-depleted biomass by N 2 -fixing organisms, contributing to the isotopic record.