Subterranean estuaries (STEs) play an important role in linking nutrient cycling between marine and terrestrial systems. As being the primary drivers of nutrient cycling, the composition of microbial communities and their adaptation towards both, terrestrial and marine conditions are of special interest. While bacterial communities of STEs have received increasing scientific attention, archaeal and meiofaunal diversity was mostly neglected. Previous studies at the investigated sampling site, the STE of a mesotidal beach at the German North Sea island of Spiekeroog, focused on spatial and seasonal patterns of geochemical and bacterial diversity. By additionally investigating the archaeal and meiofaunal diversity and distribution, we now aimed to fill this gap of knowledge to understand the microbial response to submarine groundwater discharge (SGD). The topography of Spiekeroog beach and associated geochemical gradients in porewater displayed a distinct cross-shore zonation, with seawater infiltration on the upper beach at the high water line (HWL), and saline and brackish porewater exfiltration (SGD) at the ridge-runnel structure and the low water line (LWL) on the lower beach. This led to a higher evenness of prokaryotic communities in lower beach areas impacted by SGD compared to unimpacted areas. Archaea contributed 1-4% to the 16S rRNA gene sequence dataset. Those were dominated by Nitrosopumilaceae, corresponding well to higher concentrations of NH4+ in the discharge area of the STE. The unimpacted sites had elevated abundances of Wosearchaeia, which were also detected previously in impacted areas of an STE at Mobile Bay (Gulf of Mexico). While a large proportion of prokaryotes were present in the entire intertidal area, meiofaunal community compositions were site specific and dominated by nematodes. Nematode communities of the high-water line differed distinctively from the other sites. Overall, our data indicates that the three domains of life display distinctly different adaptations when facing the same conditions within the STE. Therefore, distribution patterns of any domain can only be understood if all of them, together with basic environmental information are investigated in an integrated context.

中文翻译：

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高能海滩浅层河口泄洪区内的三个生命域

地下河口（STE）在连接海洋和陆地系统之间的养分循环方面起着重要作用。作为养分循环的主要驱动力，微生物群落的组成及其对陆地和海洋条件的适应性特别令人关注。尽管STE的细菌群落受到了越来越多的科学关注，但古细菌和藻类的多样性却大多被忽略了。先前在被调查的采样点德国北海史匹克罗格岛的一个中生代海滩的STE的研究重点是地球化学和细菌多样性的空间和季节模式。通过额外研究古细菌和半金属的多样性和分布，我们现在旨在填补这一知识空白，以了解微生物对海底地下水排放（SGD）的反应。Spiekeroog海滩的地形和相关的孔隙水地球化学梯度显示出明显的跨岸带，高水位线（HWL）的上部海滩有海水渗透，而岭-结构的盐水和微咸的孔隙水渗透（SGD）以及较低海滩上的低水位线（LWL）。与未受影响的地区相比，这导致了受到SGD影响的较低海滩地区的原核生物群落更加平坦。古细菌对16S rRNA基因序列数据集贡献1-4％。那些以亚硝基眼科（Natrosopumilaceae）为主，这与STE排放区域中较高的NH4 +浓度相对应。未受影响的地点的沃氏菌的丰度较高，以前也曾在莫比尔湾（墨西哥湾）的STE的受影响区域中发现过这些沃氏菌。虽然在整个潮间带存在大量的原核生物，但动植物群落组成是特定于地点的，并以线虫为主。高水位线虫的线虫群落与其他地点明显不同。总体而言，我们的数据表明，当面对STE中的相同条件时，三个生活领域显示出截然不同的适应。因此，只有在综合环境下研究所有领域以及基本环境信息，才能理解任何领域的分布模式。我们的数据表明，当面对STE中的相同条件时，三个生活领域显示出截然不同的适应。因此，只有在综合环境下研究所有领域以及基本环境信息，才能理解任何领域的分布模式。我们的数据表明，当面对STE中的相同条件时，三个生活领域显示出截然不同的适应。因此，只有在综合环境下研究所有领域以及基本环境信息，才能理解任何领域的分布模式。