Denitrification Aligns with N2 Fixation in Red Sea Corals
Denitrification Aligns with N2 Fixation in Red Sea Corals
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DOI：
10.1038/s41598-019-55408-z
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发表时间：
2019-12
影响因子：
4.6
通讯作者：
A. Tilstra;Y. El-Khaled;F. Roth;Nils Rädecker;C. Pogoreutz;C. Voolstra;C. Wild
中科院分区：
文献类型：
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作者：
A. Tilstra;Y. El-Khaled;F. Roth;Nils Rädecker;C. Pogoreutz;C. Voolstra;C. Wild
反硝化作用可能会潜在地减轻珊瑚全氮生物体内的过量氮(N)有效性，以维持珊瑚组织中有利的N/P比率。然而，人们对珊瑚中的反硝化细菌的丰度和活性知之甚少。本研究使用irSmark基因作为反硝化潜力的替代指标，并测量了红海比较珊瑚分类框架中的反硝化速率：红海尖顶孢藻、米孢子藻和颗粒侧耳藻。对与这些常见珊瑚组织相关的Sgene拷贝数进行了评估，并与全氮水平上的反硝化率进行了比较。此外，还对氮素固定率、共生菌科的细胞密度和放氧量进行了评估，为反硝化提供了环境背景。我们发现，iSgene的相对丰度是Ina的16倍和17倍。汤姆比他贵得多。DichoomaA和P.颗粒细胞分别为。与之一致的是，最高的反硝化速率被测得在硝酸铵。Hemprichii，然后是M。DichoomaA和P.颗粒状。反硝化速率与固氮率和共生菌科细胞密度呈正相关。我们的结果表明，反硝化作用可能会抵消珊瑚全息藻中N2固定所带来的N输入，我们推测这些过程可能受到共生生物科释放的光合作用的限制。
Denitrification may potentially alleviate excess nitrogen (N) availability in coral holobionts to maintain a favourable N to phosphorous ratio in the coral tissue. However, little is known about the abundance and activity of denitrifiers in the coral holobiont. The present study used thenirSmarker gene as a proxy for denitrification potential along with measurements of denitrification rates in a comparative coral taxonomic framework from the Red Sea:Acropora hemprichii,Millepora dichotoma, andPleuractis granulosa. RelativenirSgene copy numbers associated with the tissues of these common corals were assessed and compared with denitrification rates on the holobiont level. In addition, dinitrogen (N2) fixation rates, Symbiodiniaceae cell density, and oxygen evolution were assessed to provide an environmental context for denitrification. We found that relative abundances of thenirSgene were 16- and 17-fold higher inA. hemprichiicompared toM. dichotomaandP. granulosa, respectively. In concordance, highest denitrification rates were measured inA. hemprichii, followed byM. dichotomaandP. granulosa. Denitrification rates were positively correlated with N2fixation rates and Symbiodiniaceae cell densities. Our results suggest that denitrification may counterbalance the N input from N2fixation in the coral holobiont, and we hypothesize that these processes may be limited by photosynthates released by the Symbiodiniaceae.