In this study, we show that the deep-sea meiofauna community at the Brazilian Equatorial Margin (BEM) is strongly influenced by the Amazon River. Our comparison across four deep ocean basins including Amazon, Pará-Maranhão, Barreirinhas, and Ceará showed that the former supports a completely distinct meiofaunal community. Meiofaunal richness increased with increasing distance from the Amazon, reflecting changes in sediment proprieties among basins. Total phytopigment content at Amazon sediments was threefold higher than at other basins. The chlorophyll a/Phaeo mean ratio, however, was lower than 1, suggesting a predominant degraded bulk organic matter derived from the Amazon River discharge. Nematode assemblages from Amazon strongly differed from the other basins mostly due to higher genus richness, trophic diversity, and variations in the abundance of Sabatieria, which in turn led into higher dissimilarity values and turnover rate. Furthermore, the bathymetric distribution of nematode assemblages at Amazon and Ceará basins differed significantly among depth zones, especially due to the higher abundance and diversity at Amazon basin. Our findings show that the Amazon River plays a critical role in structuring and shaping the deep-sea meiofauna and nematode biodiversity at the BEM. Increasing impacts on the Amazon rainforest will certainly affect the amount of freshwater discharge, and the quantity and quality of organic material transported to the Atlantic Ocean, which in turn will have effects on the deep-sea communities.

中文翻译：

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亚马逊河排放影响深海小型动物群

在这项研究中，我们表明巴西赤道边缘（BEM）的深海小型动物群落受到亚马逊河的强烈影响。我们对亚马逊、Pará-Maranhão、Barreirinhas 和 Ceará 等四个深海盆地的比较表明，前者支持一个完全不同的小型动物群落。小型动物丰富度随着距亚马逊河距离的增加而增加，反映了流域之间沉积物特性的变化。亚马逊沉积物的总植物色素含量是其他盆地的三倍。叶绿素a然而，/Phaeo 平均比率低于 1，表明主要降解的散装有机物来自亚马逊河排放。亚马逊的线虫组合与其他盆地有很大不同，主要是由于更高的属丰富度、营养多样性和Sabatieria丰度的变化，这反过来又导致更高的差异值和周转率。此外，亚马逊盆地和塞阿拉盆地线虫组合的测深分布在深度区域之间存在显着差异，特别是由于亚马逊盆地的丰度和多样性较高。我们的研究结果表明，亚马逊河在构建和塑造 BEM 的深海小型动物和线虫生物多样性方面发挥着关键作用。对亚马逊雨林的影响越来越大，肯定会影响淡水排放量，以及输送到大西洋的有机物质的数量和质量，进而对深海群落产生影响。