School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, New South Wales, Australia.
Commonwealth Scientific and Industrial Research Organisation Land and Water, Lucas Heights, New South Wales, Australia.
Environ Toxicol Chem. 2021 Jul;40(7):1894-1907. doi: 10.1002/etc.5039. Epub 2021 May 13.
The Southeast Asia and Melanesia region has extensive nickel (Ni)-rich lateritic regoliths formed from the tropical weathering of ultramafic rocks. As the global demand for Ni continues to rise, these lateritic regoliths are increasingly being exploited for their economic benefit. Mining of these regoliths contributes to the enrichment of coastal sediments in trace metals, especially Ni. The present study used high-throughput sequencing (metabarcoding) to determine changes in eukaryote (18s v7 recombinant DNA [rDNA] and diatom-specific subregion of the 18s v4 rDNA) and prokaryote (16s v4 rDNA) community compositions along a sediment Ni concentration gradient offshore from a large lateritized ultramafic regolith in New Caledonia (Vavouto Bay). Significant changes in the eukaryote, diatom, and prokaryote community compositions were found along the Ni concentration gradient. These changes correlated most with the dilute-acid extractable concentration of Ni in the sediments, which explained 26, 23, and 19% of the variation for eukaryote, diatom, and prokaryote community compositions, respectively. Univariate analyses showed that there was no consistent change in indices of biodiversity, evenness, or richness. Diatom richness and diversity did, however, decrease as sediment acid extractable-Ni concentrations increased. Threshold indicator taxa analysis was conducted separately for each of the 3 targeted genes to detect changes in taxa whose occurrences decreased or increased along the acid extractable-Ni concentration gradient. Based on these data, 46 mg acid extractable-Ni/kg was determined as a threshold value where sensitive species began to disappear. In the case of the estuarine sediments offshore from lateritized ultramafic regolith in New Caledonia, this is recommended as an interim threshold value until further lines of evidence can contribute to a region-specific Ni sediment quality guideline value. Environ Toxicol Chem 2021;40:1894-1907. © 2021 SETAC.
东南亚和美拉尼西亚地区拥有广泛的镍（Ni）丰富的红土风化壳，这些风化壳是由超镁铁质岩石在热带气候条件下形成的。随着全球对 Ni 的需求持续增长，这些红土风化壳正越来越多地被开采利用，以获取经济效益。这些风化壳的开采导致沿海沉积物中痕量金属，特别是 Ni 的富集。本研究使用高通量测序（宏条形码）来确定在新喀里多尼亚（瓦武托湾）大型红土风化超镁铁质风化壳沿岸从一个大的红土风化超镁铁质风化壳沿沉积物 Ni 浓度梯度的真核生物（18s v7 重组 DNA [rDNA]和 18s v4 rDNA 硅藻特定位点）和原核生物（16s v4 rDNA）群落组成的变化。在 Ni 浓度梯度上发现真核生物、硅藻和原核生物群落组成发生了显著变化。这些变化与沉积物中稀酸可提取的 Ni 浓度最相关，分别解释了真核生物、硅藻和原核生物群落组成变化的 26%、23%和 19%。单变量分析表明，生物多样性、均匀度或丰富度的指数没有一致的变化。然而，随着沉积物酸可提取-Ni 浓度的增加，硅藻丰富度和多样性确实减少了。分别对 3 个目标基因中的每一个进行了阈值指示种分析，以检测随着酸可提取-Ni 浓度梯度变化而出现或减少的类群的变化。根据这些数据，确定 46mg 酸可提取-Ni/kg 为一个阈值，在此阈值下，敏感物种开始消失。对于来自新喀里多尼亚红土风化超镁铁质风化壳的河口沉积物，建议在进一步的证据可以为特定地区的 Ni 沉积物质量指导值做出贡献之前，将其作为一个临时阈值。Environ Toxicol Chem 2021;40:1894-1907。©2021 SETAC。
