Abstract Numerous studies on zooplankton resting eggs have focused on subtidal seafloors, but ignored intertidal zones. The hypothesis that intertidal zones have comparable community of resting eggs as subtidal seafloors was tested by investigating the mudflats and creeks of the Yangtze River Estuary with the reference of nearby subtidal sediments. A total of 25 species of resting eggs were identified using DNA barcoding of the mitochondrial gene cytochrome c oxidase subunit I. Rotifers and copepods occupied 32% and 24% of taxa, respectively. The remaining species included cladocerans, insects, arachnids, sponges and bryozoans. Both the abundance and species richness of resting eggs did not differ significantly between the intertidal and subtidal zones. Similarly, the intertidal zones had the comparable community structure as the subtidal seafloors. The intertidal mudflats and creeks, however, differed significantly in the abundance, species richness, and community structure of resting eggs. The distance to the low-tide mark, clay content, and chlorophyll a explained the main variations of egg communities. Most abundance and species richness of resting eggs occurred within the upper 15 cm sediments and greatly declined with increasing depth. Zooplankton communities were reconstructed by combining the sedimentation rate and the vertical distribution of resting eggs. Freshwater cladocerans and rotifers declined with an increase of estuarine and coastal copepods over past ten years. These results demonstrate that resting eggs in intertidal mudflats and creeks were comparable to these in subtidal zones, and were natural archives for zooplankton responses to estuarine environments. They may serve as a new link between intertidal zones and open waters, facilitate zooplankton dispersal by waterbirds, and recover past communities.

中文翻译：

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河口潮间带泥滩和小溪浮游动物产卵多样性及群落结构

摘要 大量关于浮游动物休眠卵的研究都集中在潮下带海底，而忽略了潮间带。通过调查长江口的泥滩和小溪并参考附近的潮下带沉积物，验证了潮间带具有与潮下带海底相似的休眠卵群落的假设。使用线粒体基因细胞色素 c 氧化酶亚基 I 的 DNA 条形码鉴定了总共 25 种休眠卵。轮虫和桡足类分别占分类群的 32% 和 24%。其余物种包括枝角类动物、昆虫、蜘蛛、海绵和苔藓动物。静息卵的丰度和物种丰富度在潮间带和潮下带之间没有显着差异。相似地，潮间带的群落结构与潮下海底具有可比性。然而，潮间带泥滩和小溪在休眠卵的丰度、物种丰富度和群落结构方面存在显着差异。到低潮线的距离、粘土含量和叶绿素 a 解释了卵群落的主要变化。休眠卵的大多数丰度和物种丰富度发生在上部 15 cm 沉积物中，随着深度的增加而大大下降。结合沉降速率和休眠卵的垂直分布重建浮游动物群落。淡水枝角类动物和轮虫在过去十年中随着河口和沿海桡足类动物的增加而减少。这些结果表明，潮间带泥滩和小溪中的休眠卵与潮下带的卵相似，并且是浮游动物对河口环境反应的自然档案。它们可以作为潮间带和开阔水域之间的新纽带，促进水鸟对浮游动物的传播，并恢复过去的群落。