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Impact of a wastewater treatment plant on microbial community composition and function in a hyporheic zone of a eutrophic river.

Atashgahi S, Aydin R, Dimitrov MR, Sipkema D, Hamonts K, Lahti L, Maphosa F, Kruse T, Saccenti E, Springael D, Dejonghe W, Smidt H - Sci Rep (2015)

Bottom Line: Pyrosequencing of bacterial 16S rRNA gene fragments in sediment cores showed reduced relative abundance of heterotrophs and fermenters such as Chloroflexi and Firmicutes in more oxic and nutrient poor post-WWTP sediments.This transition in the trophic state of the hyporheic sediments reduced but did not abolish the VC respiration potential in the post-WWTP sediments as an important hyporheic sediment function.Our results highlight effective nutrient load reduction and parallel microbial ecological state restoration of a human-stressed urban river as a result of installation of a WWTP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands.

ABSTRACT
The impact of the installation of a technologically advanced wastewater treatment plant (WWTP) on the benthic microbial community of a vinyl chloride (VC) impacted eutrophic river was examined two years before, and three and four years after installation of the WWTP. Reduced dissolved organic carbon and increased dissolved oxygen concentrations in surface water and reduced total organic carbon and total nitrogen content in the sediment were recorded in the post-WWTP samples. Pyrosequencing of bacterial 16S rRNA gene fragments in sediment cores showed reduced relative abundance of heterotrophs and fermenters such as Chloroflexi and Firmicutes in more oxic and nutrient poor post-WWTP sediments. Similarly, quantitative PCR analysis showed 1-3 orders of magnitude reduction in phylogenetic and functional genes of sulphate reducers, denitrifiers, ammonium oxidizers, methanogens and VC-respiring Dehalococcoides mccartyi. In contrast, members of Proteobacteria adapted to nutrient-poor conditions were enriched in post-WWTP samples. This transition in the trophic state of the hyporheic sediments reduced but did not abolish the VC respiration potential in the post-WWTP sediments as an important hyporheic sediment function. Our results highlight effective nutrient load reduction and parallel microbial ecological state restoration of a human-stressed urban river as a result of installation of a WWTP.

No MeSH data available.


Related in: MedlinePlus

Sediment core characteristics.Total organic carbon and total nitrogen content (a) and 16S rRNA gene copy numbers of bacteria and D. mccartyi (as measured by qPCR) (b) in duplicate (filled (A) and open (B) symbols) sediment core taken in 2005 (top), 2010 (middle) and 2011 (bottom). Each qPCR value represents the average value obtained from triplicate reactions. Sediment-surface water interface was considered as the zero-depth. cmbsf: centimetres below surface.
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f1: Sediment core characteristics.Total organic carbon and total nitrogen content (a) and 16S rRNA gene copy numbers of bacteria and D. mccartyi (as measured by qPCR) (b) in duplicate (filled (A) and open (B) symbols) sediment core taken in 2005 (top), 2010 (middle) and 2011 (bottom). Each qPCR value represents the average value obtained from triplicate reactions. Sediment-surface water interface was considered as the zero-depth. cmbsf: centimetres below surface.

Mentions: No obvious trends were observed in surface water temperature, concentrations of anions and cations (except Fe) in the surface water during the experimental period (Table 1): none of the q-values for the Spearman ρ correlation was found significant at the 0.25 level after Benjamini-Hochberg correction for multiple testing (Supplementary Table S3). However, dissolved organic carbon (DOC) (ρ = −0.89, q-value = 0.09), oxygen (ρ = + 0.71, q-value = 0.09), pH (ρ = −0.66, q-value = 0.09), Fe (ρ = −0.7, q-value = 0.14) and conductivity (ρ = −0.52, q-value = 0.24) showed significant differences. In particular we observed that the dissolved oxygen content in the surface water increased to above 3 mg/L in 2007 and on average above 4 mg/L after 2008 (q-value = 0.2, Kruskal-Wallis test). DOC concentrations in the surface water decreased from an average of 51 ± 27 mg/L in the period Dec 2005-May 2006 to an average of 7 ± 1 mg/L in May-Sept 2011 (q-value = 0.24). The DOC and sulphate values in interstitial water (ISW) collected by means of permanent pore water samplers were not significantly different (Table 2). The concentrations of nitrate and nitrite were always below detection limit. The total organic carbon (TOC) significantly decreased with depth (Fig. 1a, Supplementary Table S4,5) in most cores except for core-A in 2010 (ρ = −0.83, q-value = 0.29) and core-B in 2011 (ρ = 0.29, q-value = 0.87). The total nitrogen (TN) content on the other hand decreased with depth only for core-B in 2005 (ρ = −0.67, q-value = 0.19) and core-A in 2010 (ρ = −0.89, q-value = 0.19). A significant decrease over time for both TOC and TN values was observed only in the top 20 cm sediment horizon (Kruskal-Wallis q-values of 0.01 and 0.01, respectively) (Supplementary Table S6).


Impact of a wastewater treatment plant on microbial community composition and function in a hyporheic zone of a eutrophic river.

Atashgahi S, Aydin R, Dimitrov MR, Sipkema D, Hamonts K, Lahti L, Maphosa F, Kruse T, Saccenti E, Springael D, Dejonghe W, Smidt H - Sci Rep (2015)

Sediment core characteristics.Total organic carbon and total nitrogen content (a) and 16S rRNA gene copy numbers of bacteria and D. mccartyi (as measured by qPCR) (b) in duplicate (filled (A) and open (B) symbols) sediment core taken in 2005 (top), 2010 (middle) and 2011 (bottom). Each qPCR value represents the average value obtained from triplicate reactions. Sediment-surface water interface was considered as the zero-depth. cmbsf: centimetres below surface.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660315&req=5

f1: Sediment core characteristics.Total organic carbon and total nitrogen content (a) and 16S rRNA gene copy numbers of bacteria and D. mccartyi (as measured by qPCR) (b) in duplicate (filled (A) and open (B) symbols) sediment core taken in 2005 (top), 2010 (middle) and 2011 (bottom). Each qPCR value represents the average value obtained from triplicate reactions. Sediment-surface water interface was considered as the zero-depth. cmbsf: centimetres below surface.
Mentions: No obvious trends were observed in surface water temperature, concentrations of anions and cations (except Fe) in the surface water during the experimental period (Table 1): none of the q-values for the Spearman ρ correlation was found significant at the 0.25 level after Benjamini-Hochberg correction for multiple testing (Supplementary Table S3). However, dissolved organic carbon (DOC) (ρ = −0.89, q-value = 0.09), oxygen (ρ = + 0.71, q-value = 0.09), pH (ρ = −0.66, q-value = 0.09), Fe (ρ = −0.7, q-value = 0.14) and conductivity (ρ = −0.52, q-value = 0.24) showed significant differences. In particular we observed that the dissolved oxygen content in the surface water increased to above 3 mg/L in 2007 and on average above 4 mg/L after 2008 (q-value = 0.2, Kruskal-Wallis test). DOC concentrations in the surface water decreased from an average of 51 ± 27 mg/L in the period Dec 2005-May 2006 to an average of 7 ± 1 mg/L in May-Sept 2011 (q-value = 0.24). The DOC and sulphate values in interstitial water (ISW) collected by means of permanent pore water samplers were not significantly different (Table 2). The concentrations of nitrate and nitrite were always below detection limit. The total organic carbon (TOC) significantly decreased with depth (Fig. 1a, Supplementary Table S4,5) in most cores except for core-A in 2010 (ρ = −0.83, q-value = 0.29) and core-B in 2011 (ρ = 0.29, q-value = 0.87). The total nitrogen (TN) content on the other hand decreased with depth only for core-B in 2005 (ρ = −0.67, q-value = 0.19) and core-A in 2010 (ρ = −0.89, q-value = 0.19). A significant decrease over time for both TOC and TN values was observed only in the top 20 cm sediment horizon (Kruskal-Wallis q-values of 0.01 and 0.01, respectively) (Supplementary Table S6).

Bottom Line: Pyrosequencing of bacterial 16S rRNA gene fragments in sediment cores showed reduced relative abundance of heterotrophs and fermenters such as Chloroflexi and Firmicutes in more oxic and nutrient poor post-WWTP sediments.This transition in the trophic state of the hyporheic sediments reduced but did not abolish the VC respiration potential in the post-WWTP sediments as an important hyporheic sediment function.Our results highlight effective nutrient load reduction and parallel microbial ecological state restoration of a human-stressed urban river as a result of installation of a WWTP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands.

ABSTRACT
The impact of the installation of a technologically advanced wastewater treatment plant (WWTP) on the benthic microbial community of a vinyl chloride (VC) impacted eutrophic river was examined two years before, and three and four years after installation of the WWTP. Reduced dissolved organic carbon and increased dissolved oxygen concentrations in surface water and reduced total organic carbon and total nitrogen content in the sediment were recorded in the post-WWTP samples. Pyrosequencing of bacterial 16S rRNA gene fragments in sediment cores showed reduced relative abundance of heterotrophs and fermenters such as Chloroflexi and Firmicutes in more oxic and nutrient poor post-WWTP sediments. Similarly, quantitative PCR analysis showed 1-3 orders of magnitude reduction in phylogenetic and functional genes of sulphate reducers, denitrifiers, ammonium oxidizers, methanogens and VC-respiring Dehalococcoides mccartyi. In contrast, members of Proteobacteria adapted to nutrient-poor conditions were enriched in post-WWTP samples. This transition in the trophic state of the hyporheic sediments reduced but did not abolish the VC respiration potential in the post-WWTP sediments as an important hyporheic sediment function. Our results highlight effective nutrient load reduction and parallel microbial ecological state restoration of a human-stressed urban river as a result of installation of a WWTP.

No MeSH data available.


Related in: MedlinePlus