Spatial variation in bacterial community in natural wetland‐river‐sea ecosystems

Abstract

Wetland-estuarine-marine environments are typical oxic/anoxic transition zones and have complex water flow-paths within the zone of mixing where freshwater interacts with ocean water. Little is known about the impact of this interaction on bacterial community structures or the relationship between bacterial community and geochemical factors in such transitional mixing environments. Hence, we investigated the distribution patterns and diversity in bacterial communities in the Yellow River estuary-coastal wetland-Bohai Sea transition zone by analyzing 39 samples from 13 ordered sites. High-throughput sequencing of the 16S rRNA gene revealed significant shifts in diversity and distribution of bacterial community in sediments from the Yellow River estuary to the Bohai Sea. Yellow River sediment was dominated by hydrogen-, nitrogen-, and iron-cycling bacteria, such as Hydrogenophaga, Nitrospira, Pseudomonas, and Thiobacillus. The coastal wetland had a haloduric community associated with different functions, such as Planctomyces, Marinobacter, Halomonas, Salinivibrio, and Salinibacter. The Bohai Sea sediment had a higher relative abundance of Lutimonas, Desulfococcus, Photobacterium, Propionigenium, and Vibrio. Spatial variation in bacterial community was correlated with pH, salinity and sulfate (SO42-) concentration in such coastal environments. The major bacterial taxa were significantly different across the wetland, estuary, and coastal marine ecosystems, indicating substantial spatial heterogeneity among the three ecosystems. Statistical analysis revealed strong links between variation in bacterial community structure and ecosystem type. Our results demonstrate the importance of geographic and geochemical factors in structuring the bacterial community in natural environments.

Planktonic Bacterial and Archaeal Communities in an Artificially Irrigated Estuarine Wetland: Diversity, Distribution, and Responses to Environmental Parameters

“…Temporal and spatial variations in microbial biodiversity have been previously observed in natural wetlands [9,31,35] and constructed wetlands [4,14,30,32], but these studies have mostly emphasized soils [4,9,14,31,32], sediments [9,35] and rhizospheres [30]. The present study revealed the temporal and spatial dynamics of bacterial and archaeal richness, diversity and evenness in the water of an estuarine wetland.…”

Synchronous microbial vanadium (V) reduction and denitrification in groundwater using hydrogen as the sole electron donor

“…4b). Primary examples included the genera Dechloromonas and Hydrogenophaga which are reported to be autohydrogenotrophic denitrifiers (Zhang et al, 2009b;Zhang et al, 2017b) and Geobacter which promotes the reduction of V(V) (Ortiz-Bernad et al, 2004). Enriched Nitrospira, Ideonella and Methyloversatilis took part in nitrogen cycling (Shi et al, 2017;Pepe-Ranney et al, 2015;Baytshtok et al, 2009).…”

The differentiation of iron-reducing bacterial community and iron-reduction activity between riverine and marine sediments in the Yellow River estuary

“…It is also has the second largest sediment load flux to the ocean of any river (Poulton and Raiswell 2002;Pan et al 2013). Previous studies (Liu et al 2003;Qiao et al 2007;Gong et al 2015;Sheng et al 2015;Zhang et al 2017) have shown that the concentrations of ferrous iron (Fe(II)), ferric iron (Fe(III)), total iron (Fe), and ammonium (NH 4 + -N) were higher in the coastal marine sediment than in the Yellow River sediment, whereas the concentration of nitrate (NO 3 − -N) was higher in the riverine sediment than in coastal marine sediment. Patterns of IRB abundance and diversity can indicate their contribution to the biogeochemical cycles, while changes in community structures are associated with spatial variations in nutrients [i.e.,NO 3 − -N, NH 4 + -N, Fe(II), Fe(III)] in different habitats.…”

“…Salinity and pH in the overlying water at each site were measured with an electronic probe (Hydrolab MS5, HACH, USA). Nitrate (NO 3 − -N), ammonium (NH 4 + -N), total organic carbon (TOC) and total nitrogen (TN) in sediment samples, and the concentration of sulfate (SO 4 2− ) in the sediment pore waters were determined, as described in Zhang et al (2017). Dissolved ferrous iron (Fe(II)) was measured using a ferrozine-based assay (Lovley and Phillips 1987;Stookey 1970).…”

“…Here, there are steep gradients in iron, nitrogen, sulfur, oxygen, and other elements (MacDonald et al 2014). The variable river flow may result in these environments having a high variability in the concentrations of electron acceptors and electron donors (Zhang et al 2017), which are the main controlling factors of IRB community structure. These gradients, which are associated with water movement, may affect the iron-reducing bacterial community structure and their biogeochemical processes.…”