Environmental DNA Biomonitoring Reveals the Interactive Effects of Dams and Nutrient Enrichment on Aquatic Multitrophic Communities

Abstract

Dam construction and nutrient enrichment are two pervasive stressors in rivers worldwide, which trigger a sharp decline in biodiversity and ecosystem services. However, the interactive effects of both stressors on multitrophic taxonomic groups remain largely unclear. Here, we used the multitrophic datasets captured by the environmental DNA (eDNA) approach to reveal the interactions between dams and nutrient enrichment on aquatic communities from the aspects of taxonomic α diversity, β diversity, and food webs. First, our data showed that dams and nutrient enrichment jointly shaped a unique spatial pattern of aquatic communities across the four river systems, and the dissimilarity of community structure significantly declined (i.e., structural homogenization) under both stressors. Second, dams and nutrients together explained 40–50% of the variations in aquatic communities, and dams had a stronger impact on fish, aquatic insects, and bacteria, yet nutrients had a stronger power to drive protozoa, fungi, and eukaryotic algae. Finally, we found that additive, synergistic, and antagonistic interactions of dams and nutrient enrichment were common and coexisted in river systems and led to significantly simplified aquatic food webs, with decreases in modularity (synergistic) and robustness (additive) and an increase in coherence (synergistic). Overall, our study highlights that eDNA-based datasets can provide multitrophic perspectives for fostering the understanding of the interactive effects of multiple stressors on rivers.

Commonly Used Engineered Nanomaterials Improve Soil Health via Suppressing Soil-Borne Fusarium and Positively Altering Soil Microbiome

“…Approximately 0.5 g of freeze-dried soil was used for DNA extraction using the protocol of DNeasy PowerSoil Pro Kit (QIAGEN, Germany). Two primer sets were used for polymerase chain reaction (PCR). , Specifically, 799F and 1107R primer sets were used to amplify the ∼450 bp fragment of the 16S rRNA gene V3–V4 region for the detection of bacteria, and the Euka02F and Euka02R primer sets were used to amplify the ∼150 bp fragment of the 18S rRNA gene V7 region for the detection of fungi . All PCR reactions including DNA samples and blank controls (DNase/RNase-free ddH 2 O as DNA template) were performed in 20 μL of reaction mixtures.…”

Aloe Vera Extract Gel-Biosynthesized Selenium Nanoparticles Enhance Disease Resistance in Lettuce by Modulating the Metabolite Profile and Bacterial Endophytes Composition

“…Ten percent PhiX was used as a positive sequencing quality control for all MiSeq assays. 58 kRaw sequences were merged and denoised using the VSEARCH pipeline in QIIME toolkit v1.91. All cleaned sequences were clustered into Operational Taxonomic Units (OTUs) with 97% nucleotide similarity, and OTUs annotations were matched using the SILVA 138 database.…”

“…Subsequently, all PCR products were purified and pooled with equimolar quantities for library preparation and high throughput sequencing on an Illumina MiSeq PE 250 platform (Illumina, USA). Ten percent PhiX was used as a positive sequencing quality control for all MiSeq assays …”

Maximizing the Impact of Research Featuring Nucleic-Acid Sequencing Methods in Environmental Science & Technology and Environmental Science & Technology Letters

“…They have provided insights into the role of microorganisms in wastewater treatment processes, 1,2 drinking water systems, 3 and consortia capable of degrading chemical pollutants. 4,5 They have provided important insights into anthropogenic impacts on aquatic food webs 6 and the response of model organisms to chemical exposures. 7 At Environmental Science & Technology (ES&T) and Environmental Science & Technology Letters (ES&T Letters), we receive large numbers of papers utilizing nucleic-acid sequencing tools, but these papers do not always effectively address research questions or evaluate hypotheses.…”