Estuaries provide critical ecosystem services, and yet are increasingly under threat from urbanization. Non-invasive approaches to monitor biodiversity resident to or migrating through estuaries is critical to evaluate the holistic health of these ecosystems, often based entirely on water quality. In this study we compared tree of life metabarcoding (ToL-metabarcoding) biodiversity detections with measurements of physico-chemical variables (chlorophyll a, turbidity, total nitrogen, total phosphorous, dissolved oxygen) at eight sites of varying degrees of water quality in the Gold Coast Broadwater Estuary (Queensland, Australia). These sites were ranked according to an adapted Water Quality Index (WQI) score. Here, we detected 787 unique taxa, adding 137 new biodiversity records to the region, mostly micro-organisms such as bacteria, ciliates, diatoms, dinoflagellates, and cryptomonads. Sites with the lowest WQI were characterised by higher turbidity, lower dissolved oxygen, as well as higher total nitrogen and phosphorous, which correlated with an increased diversity of bacteria, ciliates, and green algae. Similarly, the composition of taxa was significantly different between sites with variable WQI values for most taxa but was less apparent for larger vertebrate groups. These findings suggest that rapid ToL-metabarcoding biodiversity detections, particularly for lower order taxonomic groups, can serve as valuable indicators of flora and fauna across the tree of life associated with dynamically shifting estuarine health along urbanized coastlines.

中文翻译：

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从陆地到海洋：环境 DNA 与城市化河口的长期水质指标相关


河口提供重要的生态系统服务，但日益受到城市化的威胁。采用非侵入性方法来监测河口栖息或迁徙的生物多样性对于评估这些生态系统的整体健康状况至关重要，通常完全基于水质。在这项研究中，我们将生命之树元条形码 (ToL-metabarcoding) 生物多样性检测与金矿区不同水质程度的八个地点的物理化学变量（叶绿素 a、浊度、总氮、总磷、溶解氧）测量结果进行了比较。海岸布罗德沃特河口（澳大利亚昆士兰州）。这些地点根据调整后的水质指数 (WQI) 评分进行排名。在这里，我们检测到了 787 个独特的类群，为该地区增加了 137 个新的生物多样性记录，其中大部分是细菌、纤毛虫、硅藻、甲藻和隐藻等微生物。 WQI 最低的地点具有较高的浊度、较低的溶解氧以及较高的总氮和磷，这与细菌、纤毛虫和绿藻多样性的增加相关。同样，对于大多数类群而言，WQI 值可变的地点之间的类群组成存在显着差异，但对于较大的脊椎动物群体而言，差异不太明显。这些发现表明，快速 ToL 元条形码生物多样性检测，尤其是低阶分类群的生物多样性检测，可以作为与沿城市化海岸线动态变化的河口健康相关的整个生命树动植物群的宝贵指标。