Interactions between nitrogen form, loading rate, and light intensity on Microcystis and Planktothrix growth and microcystin production
Interactions between nitrogen form, loading rate, and light intensity on Microcystis and Planktothrix growth and microcystin production
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DOI：
10.1016/j.hal.2018.02.001
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发表时间：
2018-03-01
期刊：
影响因子：
6.6
通讯作者：
Dick, Gregory J.
中科院分区：
文献类型：
--
作者：
Chaffin, Justin D.;Davis, Timothy W.;Dick, Gregory J.
产生毒素、形成水华的蓝藻属微囊藻属和浮游发藻属需要固定氮（N），例如硝酸盐、铵或有机N（例如，尿素）用于微囊藻毒素（MC）的生长和产生。生物可利用氮可以通过支流排放和湖内循环以脉冲方式进入湖泊，从而维持低的氮浓度。此外，光强被认为在MC产生中发挥作用。本研究探讨了三种形式的氮（硝酸盐，铵，尿素）与氮负荷率（一个大脉冲与许多小脉冲）和光强度的相互作用，以刺激微囊藻和浮游发藻的生长和MC生产营养富集实验。硝酸盐，铵和尿素的富集导致更大的蓝藻生物体积和MC浓度比磷只富集，脉冲（100 μ mol/L）和按处理（8.3 μ mol/L，每4小时）之间没有差异。mcyD成绩单的分析表明，在4小时内的铵和尿素富集显着上调。高光照强度（300 μ mol光子/m（2）/s）与N富集导致更大的蓝藻生物体积和MC浓度比低光照强度（30和3 μ mol光子/m（2）/s）。总的来说，结果表明微囊藻和浮游发藻可以使用多种形式的N和高光强度提高MC生产在N浓度升高。此外，这里的结果进一步证明了在旨在减轻蓝藻水华的管理策略中考虑N和P的重要性。(C)2018 Elsevier B. V.版权所有。
The toxin-producing, bloom-forming cyanobacterial genera Microcystis and Planktothrix require fixed nitrogen (N), such as nitrate, ammonium, or organic N (e.g., urea) for growth and production of microcystins (MC). Bioavailable N can enter lakes in pulses via tributary discharge and through in-lake recycling, which can maintain low N concentrations. Additionally, light intensity has been suggested to play a role in MC production. This study examined how three forms of N (nitrate, ammonium, and urea) interacted with N loading rate (one large pulse vs. many small pulses) and light intensity to stimulate Microcystis and Planktothrix growth and MC production using nutrient enrichment experiments. Enrichments of nitrate, ammonium, and urea resulted in greater cyanobacterial biovolumes and MC concentrations than phosphorus-only enrichments, and there was no difference between pulse (100 mu mol/L) and press treatments (8.3 mu mol/L every 4 h). Analysis of mcyD transcripts showed significant up-regulation within 4 h of ammonium and urea enrichment. High light intensities (300 mu mol photons/m(2)/s) with N enrichment resulted in greater cyanobacterial biovolumes and MC concentrations than lower light intensities (30 and 3 mu mol photons/m(2)/s). Overall, the results suggest Microcystis and Planktothrix can use many forms of N and that high light intensities enhance MC production during elevated N concentrations. Moreover, the results here further demonstrate the importance of considering N, as well as P, in management strategies aimed at mitigating cyanobacterial blooms. (C) 2018 Elsevier B.V. All rights reserved.