Chronic trace metals effects of mine tailings on estuarine assemblages revealed by environmental DNA
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Abstract
Mine tailing disasters have occurred worldwide and contemporary release of tailings of large proportions raise concerns of the chronic impacts that trace metals associated with tailings may have on the aquatic biodiversity. Environmental metabarcoding (eDNA) offers an yet poorly explored opportunity for biological monitoring of impacted aquatic ecosystems from mine tailings and contaminated sediments. eDNA has been increasingly recognized to be an effective method to detect previously unrecognized small-sized Metazoan taxa, but their ecological responses to environmental pollution has not been assessed by metabarcoding. Here we evaluated chronic effects of trace metal contamination from sediment eDNA of the Rio Doce estuary, 1.7 years after the Samarco mine tailing disaster, which released over 40 million m3of iron tailings in the Rio Doce river basin. We identified 123 new sequence variants (eOTUs) of benthic taxa and an assemblage composition dominated by Nematoda, Crustacea and Platyhelminthes; typical of other estuarine ecosystems. We detected environmental filtering on the meiofaunal assemblages and multivariate analysis revealed strong influence of Fe contamination, supporting chronic impacts from mine tailing deposition in the estuary. This was in contrast to environmental filtering of meiofaunal assemblages of non-polluted estuaries. Here we suggest that the eDNA metabarcoding technique provides an opportunity to fill up biodiversity gaps in coastal marine ecology and may become a valid method for long term monitoring studies in mine tailing disasters and estuarine ecosystems with high trace metals content.
Cite this as
2019. Chronic trace metals effects of mine tailings on estuarine assemblages revealed by environmental DNA. PeerJ Preprints 7:e27924v1 https://doi.org/10.7287/peerj.preprints.27924v1note This preprint is not peer-reviewed. You may wish to reference the subsequent peer-reviewed version of this article.
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This is a submission to PeerJ for review. This is a preprint submission to PeerJ Preprints.
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Supplemental Information
List of Metazoan taxa determined from eDNA
Table S1. List of marine eOTUs of aquatic Metazoan taxa recovered from sediment eDNA samples from the Rio Doce estuary. Note: unassigned species identities are indicated as notID.
List of dominant meiofaunal eOTUs
Table S2. Dominant meiofaunal OTUs with > 0.1% of sequence variant reads included in multivariate analysis
Spearman correlation tests of trace metals in sediments of the Rio Doce estuary in August 2017
Table S3. Results of paired spearman correlation analysis of trace metals concentrations in sediment samples from the Rio Doce estuary in August 2017.Variables were considered co-variating when the correlation coefficient (Pearson’s r) was not equal to 0 with p ≤ 0.05. Significant results (p < 0.05) are in bold.
Number of sequence variant reads from Metazoan taxa from the Rio Doce estuary in August 2017
Number of sequence variant reads from Metazoan taxa from the Rio Doce estuary in August 2017, distributed across sites sampled
Additional Information
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Angelo F Bernardino conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Fabiano S Pais performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Louisi S Oliveira performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Fabricio A Gabriel performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Tiago O Ferreira performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Hermano M Queiroz performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Ana Carolina A Mazzuco performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Field Study Permissions
The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):
Field sampling was approved by the SISBIO-IBAMA.
Data Deposition
The following information was supplied regarding data availability:
The raw data and supplementary tables are provided in supplementary files 1 and 2. The raw data shows all sequence reads from metazoans identified by eDNA metabarcoding.
Funding
This work was funded by grants to AFB and TOF from Fundação de Amparo do Espirito Santo (FAPES Rio Doce 77683544/2017, Sinapse 81712405/2018), CAPES and CNPq (grant numbers 301161/2017-8 and 305996/2018-5). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.