Patterns of Change in Metabolic Capabilities of Sediment Microbial Communities in River and Lake Ecosystems.

Adam Oest,Ali Alsaffar,Sonia M Tiquia-Arashiro,Mitchell Fenner,Dominic Azzopardi

doi:10.1155/2018/6234931

Adam Oest, Ali Alsaffar + Show 3 more

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https://doi.org/10.1155/2018/6234931

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Abstract

Information on the biodegradation potential of lake and river microbial communities is essential for watershed management. The water draining into the lake ecosystems often carries a significant amount of suspended sediments, which are transported by rivers and streams from the local drainage basin. The organic carbon processing in the sediments is executed by heterotrophic microbial communities, whose activities may vary spatially and temporally. Thus, to capture and apprehend some of these variabilities in the sediments, we sampled six sites: three from the Saint Clair River (SC1, SC2, and SC3) and three from Lake Saint Clair in the spring, summer, fall, and winter of 2016. Here, we investigated the shifts in metabolic profiles of sediment microbial communities, along Saint Clair River and Lake Saint Clair using Biolog EcoPlates, which test for the oxidation of 31 carbon sources. The number of utilized substrates was generally higher in the river sediments (upstream) than in the lake sediments (downstream), suggesting a shift in metabolic activities among microbial assemblages. Seasonal and site-specific differences were also found in the numbers of utilized substrates, which were similar in the summer and fall, and spring and winter. The sediment microbial communities in the summer and fall showed more versatile substrate utilization patterns than spring and winter communities. The functional fingerprint analyses clearly distinguish the sediment microbial communities from the lake sites (downstream more polluted sites), which showed a potential capacity to use more complex carbon substrates such as polymers. This study establishes a close linkage between physical and chemical properties (temperature and organic matter content) of lake and river sediments and associated microbial functional activities.

Highlights

Lake Saint Clair and the Saint Clair River are important resources for about six million U.S and Canadian residents who live close to the watershed [1, 2]. e lake and river are defining natural features of Southeast Michigan and Southwestern Ontario and are used for fishing, recreational boating, drinking, and commercial navigation. ey are dynamic parts of the larger Great Lakes system
We investigated the shifts in metabolic profiles of sediment microbial communities, along Saint Clair River and Lake Saint Clair using Biolog EcoPlates, which test for the oxidation of 31 carbon sources. e number of utilized substrates was generally higher in the river sediments than in the lake sediments, suggesting a shift in metabolic activities among microbial assemblages
Lake Saint Clair and the Saint Clair River connect between the upper and lower Great Lakes and are used for both commercial navigation and fish and wildlife that live in or move across the area [3]. ey are the outlet for the three upper Great Lakes, with more than 90% of the average annual water supply to Lake Erie and nearly 75% of the supply to Lake

Summary

Introduction

Lake Saint Clair and the Saint Clair River are important resources for about six million U.S and Canadian residents who live close to the watershed [1, 2]. e lake and river are defining natural features of Southeast Michigan and Southwestern Ontario and are used for fishing, recreational boating, drinking, and commercial navigation. ey are dynamic parts of the larger Great Lakes system. Pollutants in the Saint Clair River and Lake Saint Clair sediments include toxic organic compounds such as organochlorine insecticides, PCBs, chlorobenzenes, chlorotoluenes, and chlorostyrenes [2, 5,6,7]. Sediment microorganisms play key roles in nutrient cycling, heavy metal immobilization [21,22,23], and degradation of organic compounds [24] As such, they can be used as a potential bioremediation strategy to overcome pollution problems associated with a local river or lake [8, 22, 25, 26]. Nutrients and heavy metal contamination have been shown to cause changes in bacterial biomass, diversity, and function [21]

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