Urbanization Altered Bacterial and Archaeal Composition in Tidal Freshwater Wetlands Near Washington DC, USA, and Buenos Aires, Argentina.

Martina Gonzalez Mateu,Andrew Baldwin,Stephanie Yarwood,Cedric Park,Cullen Mcaskill

doi:10.3390/microorganisms7030072

Martina Gonzalez Mateu, Andrew Baldwin + Show 3 more

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https://doi.org/10.3390/microorganisms7030072

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Journal: Microorganisms	Publication Date: Mar 6, 2019
Citations: 3	License type: CC BY 4.0

Affiliation: University of Maryland, College Park

Abstract

Urban expansion causes coastal wetland loss, and environmental stressors associated with development can lead to wetland degradation and loss of ecosystem services. This study investigated the effect of urbanization on prokaryotic community composition in tidal freshwater wetlands. Sites in an urban, suburban, and rural setting were located near Buenos Aires, Argentina, and Washington D.C., USA. We sampled soil associated with two pairs of functionally similar plant species, and used Illumina sequencing of the 16S rRNA gene to examine changes in prokaryotic communities. Urban stressors included raw sewage inputs, nutrient pollution, and polycyclic aromatic hydrocarbons. Prokaryotic communities changed along the gradient (nested PerMANOVA, Buenos Aires: p = 0.005; Washington D.C.: p = 0.001), but did not differ between plant species within sites. Indicator taxa included Methanobacteria in rural sites, and nitrifying bacteria in urban sites, and we observed a decrease in methanogens and an increase in ammonia-oxidizers from rural to urban sites. Functional profiles in the Buenos Aires communities showed higher abundance of pathways related to nitrification and xenobiotic degradation in the urban site. These results suggest that changes in prokaryotic taxa across the gradient were due to surrounding stressors, and communities in urban and rural wetlands are likely carrying out different functions.

Highlights

Global urbanization has rapidly increased throughout the last 60 years, and by 2050, two-thirds of the world population will live in urban settlements [1]
In Washington D.C., pH increased from rural to urban sites, while %SOM decreased along the gradient
In Buenos Aires, %SOM and %clay were significantly correlated to community composition (R2 = 0.63, p = 0.001 and R2 = 0.41, p = 0.014, respectively), and those variables were correlated to each other (r = 0.78)

Summary

Introduction

Global urbanization has rapidly increased throughout the last 60 years, and by 2050, two-thirds of the world population will live in urban settlements [1]. Population growth and the resulting urban expansion is a major cause of wetland loss worldwide [2,3]. Coastal wetlands are susceptible to loss and habitat degradation, as the most dramatic population growth has occurred in cities located near coastlines [4,5]. Urban development has a direct effect on wetland ecosystem services, and the loss and degradation of these systems can impact human health and well-being [6]. Increased impervious surfaces facilitate the transport of pollutants into waterways and directly impact wetland habitat quality [7]. Urban wetlands tend to have more non-native plant species, typically favored by nutrient inputs, and higher sediment concentrations of heavy metals and organic chemicals [11,12]

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