The RNA/DNA ratio is used as indicator of growth in various marine organisms and to assess physiological status at species or community level. To evaluate the utility of the RNA/DNA ratio as a proxy of phytoplankton primary production, the relationships between phytoplankton RNA/DNA, taxon-specific diatom and dinoflagellate 18S rRNA/rDNA ratios and autotrophic phytoplankton biomass were investigated as a first step. Significant correlations between all phytoplankton ratios and total phytoplankton, diatom and dinoflagellate biomass as chlorophyll a (chl a) and carbon content were found. Diatoms showed higher correlation than dinoflagellates (18S rRNA/rDNA vs. chl a, r_s = 0.74 and 0.64, P < 0.001; 18S rRNA/rDNA vs. carbon, r_s = 0.66 and 0.53, P < 0.001, respectively), because they represented the most abundant and frequent group within sampled assemblages. Further, phytoplankton biomass production is known to be linked to protein biosynthesis and significant relationships between RNA/DNA ratios and protein content of phytoplankton assemblage were found (r_s = 0.62 and 0.52, P < 0.001 for diatom and dinoflagellates, respectively). As taxon-specific RNA/DNA ratios were correlated with biomass and protein content, our results can be regarded as the first step toward further studies on the applicability of RNA/DNA ratios as indicators of growth rate and primary production in phytoplankton assemblages.

中文翻译：

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沿海海洋生态系统中的浮游植物 RNA/DNA 和 18S rRNA/rDNA 比率

RNA/DNA 比率被用作各种海洋生物的生长指标，并用于评估物种或群落水平的生理状态。为了评估 RNA/DNA 比率作为浮游植物初级生产代理的效用，首先研究了浮游植物 RNA/DNA、分类群特异性硅藻和甲藻 18S rRNA/rDNA 比率和自养浮游植物生物量之间的关系。所有浮游植物比率和总浮游植物，硅藻和甲藻生物质作为叶绿素之间的相关性显著一个（CHL一个被发现）和碳含量。硅藻显示比甲藻较高的相关性（18S rRNA基因/ rDNA序列与叶绿素一个，- [R_小号 = 0.74和0.64，P < 0.001; 18S rRNA/rDNA 与碳，r _s  = 0.66 和 0.53  ，分别为P < 0.001），因为它们代表了采样组合中最丰富和最频繁的组。此外，已知浮游植物生物量产生与蛋白质生物合成有关，并且发现 RNA/DNA 比率与浮游植物组合的蛋白质含量之间存在显着关系（r _s  = 0.62 和 0.52，P < 0.001 对于硅藻和鞭毛藻，分别）。由于分类群特异性 RNA/DNA 比率与生物量和蛋白质含量相关，我们的结果可以被视为进一步研究 RNA/DNA 比率作为浮游植物组合中生长速率和初级生产指标的适用性的第一步。